PchManager: Split pch tasks in project and system pch tasks

Like you can see in the task numbers this patch is touching many different
areas. So I will only touch the main parts. It is using a clang action
instead of an extra process which will be enabling the handling of
generated files in PCHs. The flags from the project part are now not
anymore transformed in a command line but they are saved in the container
semantically aware so that they can later be merged. Most of this patch is
simply polishing of other patches.

Task-number: QTCREATORBUG-21346
Task-number: QTCREATORBUG-21380
Task-number: QTCREATORBUG-21382
Task-number: QTCREATORBUG-21383
Task-number: QTCREATORBUG-21693
Task-number: QTCREATORBUG-21778
Change-Id: I9b0c02d8149b554254e819448fbc61eeaa5b7494
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

114 files changed, 3748 insertions, 1793 deletions

diff --git a/src/libs/clangsupport/clangsupport-lib.pri b/src/libs/clangsupport/clangsupport-lib.pri
index 03713650ad..221ccfd001 100644
--- a/src/libs/clangsupport/clangsupport-lib.pri
+++ b/src/libs/clangsupport/clangsupport-lib.pri
@@ -44,7 +44,6 @@ SOURCES += \
     $$PWD/pchmanagerserverinterface.cpp \
     $$PWD/pchmanagerserverproxy.cpp \
     $$PWD/precompiledheadersupdatedmessage.cpp \
-    $$PWD/projectpartcontainerv2.cpp \
     $$PWD/projectpartpch.cpp \
     $$PWD/readmessageblock.cpp \
     $$PWD/refactoringclientinterface.cpp \
@@ -87,7 +86,8 @@ SOURCES += \
     $$PWD/baseserverproxy.cpp \
     $$PWD/updategeneratedfilesmessage.cpp \
     $$PWD/removegeneratedfilesmessage.cpp \
-    $$PWD/generatedfiles.cpp
+    $$PWD/generatedfiles.cpp \
+    $$PWD/projectpartcontainer.cpp
 
 HEADERS += \
     $$PWD/cancelmessage.h \
@@ -138,7 +138,6 @@ HEADERS += \
     $$PWD/pchmanagerserverinterface.h \
     $$PWD/pchmanagerserverproxy.h \
     $$PWD/precompiledheadersupdatedmessage.h \
-    $$PWD/projectpartcontainerv2.h \
     $$PWD/projectpartpch.h \
     $$PWD/readmessageblock.h \
     $$PWD/refactoringclientinterface.h \
@@ -205,6 +204,9 @@ HEADERS += \
     $$PWD/generatedfiles.h \
     $$PWD/generatedfilesinterface.h \
     $$PWD/progressmessage.h \
-    $$PWD/progresscounter.h
+    $$PWD/progresscounter.h \
+    $$PWD/includesearchpath.h \
+    $$PWD/commandlinebuilder.h \
+    $$PWD/projectpartcontainer.h
 
 contains(QT_CONFIG, reduce_exports):CONFIG += hide_symbols
diff --git a/src/libs/clangsupport/commandlinebuilder.h b/src/libs/clangsupport/commandlinebuilder.h
new file mode 100644
index 0000000000..af9c0f1baf
--- /dev/null
+++ b/src/libs/clangsupport/commandlinebuilder.h
@@ -0,0 +1,258 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include "filepathview.h"
+
+#include <compilermacro.h>
+#include <includesearchpath.h>
+
+#include <utils/smallstringvector.h>
+#include <utils/cpplanguage_details.h>
+
+namespace ClangBackEnd {
+
+template<typename ProjectInfo, typename OutputContainer = std::vector<std::string>>
+class CommandLineBuilder
+{
+public:
+    CommandLineBuilder(const ProjectInfo &projectInfo,
+                       const Utils::SmallStringVector &toolChainArguments = {},
+                       FilePathView sourcePath = {},
+                       FilePathView outputPath = {},
+                       FilePathView includePchPath = {})
+    {
+        commandLine.reserve(128);
+
+        addCompiler(projectInfo.language);
+        addToolChainArguments(toolChainArguments);
+        addLanguage(projectInfo);
+        addLanguageVersion(projectInfo);
+        addNoStdIncAndNoStdLibInc();
+        addProjectIncludeSearchPaths(
+            sortedIncludeSearchPaths(projectInfo.projectIncludeSearchPaths));
+        addSystemAndBuiltInIncludeSearchPaths(
+            sortedIncludeSearchPaths(projectInfo.systemIncludeSearchPaths));
+        addIncludePchPath(includePchPath);
+        addOutputPath(outputPath);
+        addSourcePath(sourcePath);
+    }
+
+    void addCompiler(Utils::Language language)
+    {
+        if (language == Utils::Language::Cxx)
+            commandLine.emplace_back("clang++");
+        else
+            commandLine.emplace_back("clang");
+    }
+
+    void addToolChainArguments(const Utils::SmallStringVector &toolChainArguments)
+    {
+        for (Utils::SmallStringView argument : toolChainArguments)
+            commandLine.emplace_back(argument);
+    }
+
+    static const char *language(const ProjectInfo &projectInfo)
+    {
+        switch (projectInfo.language) {
+        case Utils::Language::C:
+            if (projectInfo.languageExtension && Utils::LanguageExtension::ObjectiveC)
+                return "objective-c-header";
+
+            return "c-header";
+        case Utils::Language::Cxx:
+            if (projectInfo.languageExtension && Utils::LanguageExtension::ObjectiveC)
+                return "objective-c++-header";
+        }
+
+        return "c++-header";
+    }
+
+    void addLanguage(const ProjectInfo &projectInfo)
+    {
+        commandLine.emplace_back("-x");
+        commandLine.emplace_back(language(projectInfo));
+    }
+
+    const char *standardLanguageVersion(Utils::LanguageVersion languageVersion)
+    {
+        switch (languageVersion) {
+        case Utils::LanguageVersion::C89:
+            return "-std=c89";
+        case Utils::LanguageVersion::C99:
+            return "-std=c99";
+        case Utils::LanguageVersion::C11:
+            return "-std=c11";
+        case Utils::LanguageVersion::C18:
+            return "-std=c18";
+        case Utils::LanguageVersion::CXX98:
+            return "-std=c++98";
+        case Utils::LanguageVersion::CXX03:
+            return "-std=c++03";
+        case Utils::LanguageVersion::CXX11:
+            return "-std=c++11";
+        case Utils::LanguageVersion::CXX14:
+            return "-std=c++14";
+        case Utils::LanguageVersion::CXX17:
+            return "-std=c++17";
+        case Utils::LanguageVersion::CXX2a:
+            return "-std=c++2a";
+        }
+
+        return "-std=c++2a";
+    }
+
+    const char *gnuLanguageVersion(Utils::LanguageVersion languageVersion)
+    {
+        switch (languageVersion) {
+        case Utils::LanguageVersion::C89:
+            return "-std=gnu89";
+        case Utils::LanguageVersion::C99:
+            return "-std=gnu99";
+        case Utils::LanguageVersion::C11:
+            return "-std=gnu11";
+        case Utils::LanguageVersion::C18:
+            return "-std=gnu18";
+        case Utils::LanguageVersion::CXX98:
+            return "-std=gnu++98";
+        case Utils::LanguageVersion::CXX03:
+            return "-std=gnu++03";
+        case Utils::LanguageVersion::CXX11:
+            return "-std=gnu++11";
+        case Utils::LanguageVersion::CXX14:
+            return "-std=gnu++14";
+        case Utils::LanguageVersion::CXX17:
+            return "-std=gnu++17";
+        case Utils::LanguageVersion::CXX2a:
+            return "-std=gnu++2a";
+        }
+
+        return "-std=gnu++2a";
+    }
+
+    const char *includeOption(IncludeSearchPathType type)
+    {
+        switch (type) {
+        case IncludeSearchPathType::User:
+        case IncludeSearchPathType::System:
+        case IncludeSearchPathType::BuiltIn:
+            return "-isystem";
+        case IncludeSearchPathType::Framework:
+            return "-F";
+        case IncludeSearchPathType::Invalid:
+            return "";
+        }
+
+        return "-I";
+    }
+
+    void addLanguageVersion(const ProjectInfo &projectInfo)
+    {
+        if (projectInfo.languageExtension && Utils::LanguageExtension::Gnu)
+            commandLine.emplace_back(gnuLanguageVersion(projectInfo.languageVersion));
+        else
+            commandLine.emplace_back(standardLanguageVersion(projectInfo.languageVersion));
+    }
+
+    IncludeSearchPaths sortedIncludeSearchPaths(const IncludeSearchPaths &unsortedPaths)
+    {
+        IncludeSearchPaths paths = unsortedPaths;
+        std::sort(paths.begin(), paths.end(), [](const auto &first, const auto &second) {
+            return first.index < second.index;
+        });
+
+        return paths;
+    }
+
+    void addProjectIncludeSearchPaths(const IncludeSearchPaths &projectIncludeSearchPaths)
+    {
+        for (const IncludeSearchPath &path : projectIncludeSearchPaths) {
+            commandLine.emplace_back("-I");
+            commandLine.emplace_back(path.path);
+        }
+    }
+
+    void addSystemAndBuiltInIncludeSearchPaths(const IncludeSearchPaths &systemIncludeSearchPaths)
+    {
+        addSystemIncludeSearchPaths(systemIncludeSearchPaths);
+        addBuiltInSystemSearchPaths(systemIncludeSearchPaths);
+    }
+
+    void addSystemIncludeSearchPaths(const IncludeSearchPaths &systemIncludeSearchPaths)
+    {
+        for (const IncludeSearchPath &path : systemIncludeSearchPaths) {
+            if (path.type != IncludeSearchPathType::BuiltIn) {
+                commandLine.emplace_back(includeOption(path.type));
+                commandLine.emplace_back(path.path);
+            }
+        }
+    }
+
+    void addBuiltInSystemSearchPaths(const IncludeSearchPaths &systemIncludeSearchPaths)
+    {
+        for (const IncludeSearchPath &path : systemIncludeSearchPaths) {
+            if (path.type == IncludeSearchPathType::BuiltIn) {
+                commandLine.emplace_back(includeOption(path.type));
+                commandLine.emplace_back(path.path);
+            }
+        }
+    }
+
+    void addOutputPath(FilePathView outputPath)
+    {
+        if (!outputPath.isEmpty()) {
+            commandLine.emplace_back("-o");
+            commandLine.emplace_back(outputPath);
+        }
+    }
+
+    void addSourcePath(FilePathView sourcePath)
+    {
+        if (!sourcePath.isEmpty())
+            commandLine.emplace_back(sourcePath);
+    }
+
+    void addIncludePchPath(FilePathView includePchPath)
+    {
+        if (!includePchPath.isEmpty()) {
+            commandLine.emplace_back("-Xclang");
+            commandLine.emplace_back("-include-pch");
+            commandLine.emplace_back("-Xclang");
+            commandLine.emplace_back(includePchPath);
+        }
+    }
+
+    void addNoStdIncAndNoStdLibInc()
+    {
+        commandLine.emplace_back("-nostdinc");
+        commandLine.emplace_back("-nostdlibinc");
+    }
+
+public:
+    OutputContainer commandLine;
+};
+
+} // namespace ClangBackEnd
diff --git a/src/libs/clangsupport/filepath.h b/src/libs/clangsupport/filepath.h
index 9ff019de76..e08f3f4996 100644
--- a/src/libs/clangsupport/filepath.h
+++ b/src/libs/clangsupport/filepath.h
@@ -51,6 +51,14 @@ public:
         m_slashIndex = view.slashIndex();
     }
 
+    explicit FilePath(Utils::SmallStringView &&filePath)
+        : Utils::PathString(filePath)
+    {
+        FilePathView view{*this};
+
+        m_slashIndex = view.slashIndex();
+    }
+
     FilePath(FilePathView filePathView)
         : Utils::PathString(filePathView.toStringView()),
           m_slashIndex(filePathView.slashIndex())
diff --git a/src/libs/clangsupport/filepathview.h b/src/libs/clangsupport/filepathview.h
index 27dac8377f..09b940fa61 100644
--- a/src/libs/clangsupport/filepathview.h
+++ b/src/libs/clangsupport/filepathview.h
@@ -37,6 +37,7 @@ template <char WindowsSlash>
 class AbstractFilePathView : public Utils::SmallStringView
 {
 public:
+    constexpr AbstractFilePathView() = default;
     explicit AbstractFilePathView(const char *const string, const size_type size) noexcept
         : Utils::SmallStringView(string, size),
           m_slashIndex(lastSlashIndex(*this))
diff --git a/src/libs/clangsupport/includesearchpath.h b/src/libs/clangsupport/includesearchpath.h
new file mode 100644
index 0000000000..239af9c1a4
--- /dev/null
+++ b/src/libs/clangsupport/includesearchpath.h
@@ -0,0 +1,102 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include <utils/smallstringio.h>
+
+#include <QDataStream>
+
+#include <vector>
+
+namespace ClangBackEnd {
+
+enum class IncludeSearchPathType : unsigned char {
+    Invalid,
+    User,
+    BuiltIn,
+    System,
+    Framework,
+};
+
+class IncludeSearchPath
+{
+public:
+    IncludeSearchPath() = default;
+    IncludeSearchPath(Utils::PathString &&path, int index, IncludeSearchPathType type)
+        : path(std::move(path))
+        , index(index)
+        , type(type)
+    {}
+
+    IncludeSearchPath(Utils::PathString &&path, int index, int type)
+        : path(std::move(path))
+        , index(index)
+        , type(static_cast<IncludeSearchPathType>(type))
+    {}
+
+    friend QDataStream &operator<<(QDataStream &out, const IncludeSearchPath &includeSearchPath)
+    {
+        out << includeSearchPath.path;
+        out << includeSearchPath.index;
+        out << static_cast<unsigned char>(includeSearchPath.type);
+
+        return out;
+    }
+
+    friend QDataStream &operator>>(QDataStream &in, IncludeSearchPath &includeSearchPath)
+    {
+        unsigned char type;
+
+        in >> includeSearchPath.path;
+        in >> includeSearchPath.index;
+        in >> type;
+
+        includeSearchPath.type = static_cast<IncludeSearchPathType>(type);
+
+        return in;
+    }
+
+    friend bool operator==(const IncludeSearchPath &first, const IncludeSearchPath &second)
+    {
+        return std::tie(first.type, first.index, first.path)
+               == std::tie(second.type, second.index, second.path);
+    }
+
+    friend bool operator<(const IncludeSearchPath &first, const IncludeSearchPath &second)
+    {
+        return std::tie(first.path, first.index, first.type)
+               < std::tie(second.path, second.index, second.type);
+    }
+
+public:
+    Utils::PathString path;
+    int index = -1;
+    IncludeSearchPathType type = IncludeSearchPathType::Invalid;
+};
+
+using IncludeSearchPaths = std::vector<IncludeSearchPath>;
+
+} // namespace ClangBackEnd
diff --git a/src/libs/clangsupport/progresscounter.h b/src/libs/clangsupport/progresscounter.h
index 1958f6ef8c..fbdc9dda45 100644
--- a/src/libs/clangsupport/progresscounter.h
+++ b/src/libs/clangsupport/progresscounter.h
@@ -40,23 +40,29 @@ public:
 
     void addTotal(int total)
     {
-        m_total += total;
+        if (total) {
+            m_total += total;
 
-        m_progressCallback(m_progress, m_total);
+            m_progressCallback(m_progress, m_total);
+        }
     }
 
     void removeTotal(int total)
     {
-        m_total -= total;
+        if (total) {
+            m_total -= total;
 
-        sendProgress();
+            sendProgress();
+        }
     }
 
     void addProgress(int progress)
     {
-        m_progress += progress;
+        if (progress) {
+            m_progress += progress;
 
-        sendProgress();
+            sendProgress();
+        }
     }
 
     void sendProgress()
diff --git a/src/libs/clangsupport/projectpartcontainerv2.cpp b/src/libs/clangsupport/projectpartcontainer.cpp
index 7d03f9486d..a51e927db5 100644
--- a/src/libs/clangsupport/projectpartcontainerv2.cpp
+++ b/src/libs/clangsupport/projectpartcontainer.cpp
@@ -23,22 +23,19 @@
 **
 ****************************************************************************/
 
-#include "projectpartcontainerv2.h"
+#include "projectpartcontainer.h"
 
 namespace ClangBackEnd {
-namespace V2 {
 
 QDebug operator<<(QDebug debug, const ProjectPartContainer &container)
 {
     debug.nospace() << "ProjectPartContainer("
                     << container.projectPartId << ","
-                    << container.arguments << ", "
+                    << container.toolChainArguments << ", "
                     << container.headerPathIds << ", "
                     << container.sourcePathIds
                     << ")";
 
     return debug;
 }
-
-} // namespace V2
 } // namespace ClangBackEnd
diff --git a/src/libs/clangsupport/projectpartcontainer.h b/src/libs/clangsupport/projectpartcontainer.h
new file mode 100644
index 0000000000..d805ef5aad
--- /dev/null
+++ b/src/libs/clangsupport/projectpartcontainer.h
@@ -0,0 +1,164 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include "clangsupport_global.h"
+
+#include "compilermacro.h"
+#include "filepathid.h"
+#include "includesearchpath.h"
+
+#include <utils/cpplanguage_details.h>
+#include <utils/smallstringio.h>
+
+namespace ClangBackEnd {
+
+class ProjectPartContainer
+{
+    using uchar = unsigned char;
+public:
+    ProjectPartContainer() = default;
+    ProjectPartContainer(Utils::SmallString &&projectPartId,
+                         Utils::SmallStringVector &&arguments,
+                         CompilerMacros &&compilerMacros,
+                         IncludeSearchPaths &&systemIncludeSearchPaths,
+                         IncludeSearchPaths &&projectIncludeSearchPaths,
+                         FilePathIds &&headerPathIds,
+                         FilePathIds &&sourcePathIds,
+                         Utils::Language language,
+                         Utils::LanguageVersion languageVersion,
+                         Utils::LanguageExtension languageExtension)
+        : projectPartId(std::move(projectPartId))
+        , toolChainArguments(std::move(arguments))
+        , compilerMacros(std::move(compilerMacros))
+        , systemIncludeSearchPaths(std::move(systemIncludeSearchPaths))
+        , projectIncludeSearchPaths(std::move(projectIncludeSearchPaths))
+        , headerPathIds(std::move(headerPathIds))
+        , sourcePathIds(std::move(sourcePathIds))
+        , language(language)
+        , languageVersion(languageVersion)
+        , languageExtension(languageExtension)
+    {
+    }
+
+    friend QDataStream &operator<<(QDataStream &out, const ProjectPartContainer &container)
+    {
+        out << container.projectPartId;
+        out << container.toolChainArguments;
+        out << container.compilerMacros;
+        out << container.systemIncludeSearchPaths;
+        out << container.projectIncludeSearchPaths;
+        out << container.headerPathIds;
+        out << container.sourcePathIds;
+        out << uchar(container.language);
+        out << uchar(container.languageVersion);
+        out << uchar(container.languageExtension);
+        return out;
+    }
+
+    friend QDataStream &operator>>(QDataStream &in, ProjectPartContainer &container)
+    {
+        uchar language;
+        uchar languageVersion;
+        uchar languageExtension;
+
+        in >> container.projectPartId;
+        in >> container.toolChainArguments;
+        in >> container.compilerMacros;
+        in >> container.systemIncludeSearchPaths;
+        in >> container.projectIncludeSearchPaths;
+        in >> container.headerPathIds;
+        in >> container.sourcePathIds;
+        in >> language;
+        in >> languageVersion;
+        in >> languageExtension;
+
+        container.language = static_cast<Utils::Language>(language);
+        container.languageVersion = static_cast<Utils::LanguageVersion>(languageVersion);
+        container.languageExtension = static_cast<Utils::LanguageExtension>(languageExtension);
+
+        return in;
+    }
+
+    friend bool operator==(const ProjectPartContainer &first, const ProjectPartContainer &second)
+    {
+        return first.projectPartId == second.projectPartId
+            && first.toolChainArguments == second.toolChainArguments
+            && first.compilerMacros == second.compilerMacros
+            && first.systemIncludeSearchPaths == second.systemIncludeSearchPaths
+            && first.projectIncludeSearchPaths == second.projectIncludeSearchPaths
+            && first.headerPathIds == second.headerPathIds
+            && first.sourcePathIds == second.sourcePathIds&& first.language == second.language
+               && first.languageVersion == second.languageVersion
+               && first.languageExtension == second.languageExtension;
+    }
+
+    friend bool operator<(const ProjectPartContainer &first, const ProjectPartContainer &second)
+    {
+        return std::tie(first.projectPartId,
+                        first.toolChainArguments,
+                        first.compilerMacros,
+                        first.systemIncludeSearchPaths,
+                        first.projectIncludeSearchPaths,
+                        first.headerPathIds,
+                        first.sourcePathIds,
+                        first.language,
+                        first.languageVersion,
+                        first.languageExtension)
+               < std::tie(second.projectPartId,
+                          second.toolChainArguments,
+                          second.compilerMacros,
+                          second.systemIncludeSearchPaths,
+                          second.projectIncludeSearchPaths,
+                          second.headerPathIds,
+                          second.sourcePathIds,
+                          second.language,
+                          second.languageVersion,
+                          second.languageExtension);
+    }
+
+    ProjectPartContainer clone() const
+    {
+        return *this;
+    }
+
+public:
+    Utils::SmallString projectPartId;
+    Utils::SmallStringVector toolChainArguments;
+    CompilerMacros compilerMacros;
+    IncludeSearchPaths systemIncludeSearchPaths;
+    IncludeSearchPaths projectIncludeSearchPaths;
+    FilePathIds headerPathIds;
+    FilePathIds sourcePathIds;
+    Utils::Language language = Utils::Language::Cxx;
+    Utils::LanguageVersion languageVersion = Utils::LanguageVersion::CXX98;
+    Utils::LanguageExtension languageExtension = Utils::LanguageExtension::None;
+};
+
+using ProjectPartContainers = std::vector<ProjectPartContainer>;
+
+QDebug operator<<(QDebug debug, const ProjectPartContainer &container);
+} // namespace ClangBackEnd
diff --git a/src/libs/clangsupport/projectpartcontainerv2.h b/src/libs/clangsupport/projectpartcontainerv2.h
deleted file mode 100644
index be21ad874f..0000000000
--- a/src/libs/clangsupport/projectpartcontainerv2.h
+++ /dev/null
@@ -1,125 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2016 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of Qt Creator.
-**
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 3 as published by the Free Software
-** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-3.0.html.
-**
-****************************************************************************/
-
-#pragma once
-
-#include "clangsupport_global.h"
-
-#include "compilermacro.h"
-#include "filepathid.h"
-
-#include <utils/smallstringio.h>
-
-namespace ClangBackEnd {
-namespace V2 {
-
-class ProjectPartContainer
-{
-public:
-    ProjectPartContainer() = default;
-    ProjectPartContainer(Utils::SmallString &&projectPartId,
-                         Utils::SmallStringVector &&arguments,
-                         CompilerMacros &&compilerMacros,
-                         Utils::SmallStringVector &&includeSearchPaths,
-                         FilePathIds &&headerPathIds,
-                         FilePathIds &&sourcePathIds)
-        : projectPartId(std::move(projectPartId)),
-          arguments(std::move(arguments)),
-          compilerMacros(std::move(compilerMacros)),
-          includeSearchPaths(std::move(includeSearchPaths)),
-          headerPathIds(std::move(headerPathIds)),
-          sourcePathIds(std::move(sourcePathIds))
-    {
-    }
-
-    friend QDataStream &operator<<(QDataStream &out, const ProjectPartContainer &container)
-    {
-        out << container.projectPartId;
-        out << container.arguments;
-        out << container.compilerMacros;
-        out << container.includeSearchPaths;
-        out << container.headerPathIds;
-        out << container.sourcePathIds;
-
-        return out;
-    }
-
-    friend QDataStream &operator>>(QDataStream &in, ProjectPartContainer &container)
-    {
-        in >> container.projectPartId;
-        in >> container.arguments;
-        in >> container.compilerMacros;
-        in >> container.includeSearchPaths;
-        in >> container.headerPathIds;
-        in >> container.sourcePathIds;
-
-        return in;
-    }
-
-    friend bool operator==(const ProjectPartContainer &first, const ProjectPartContainer &second)
-    {
-        return first.projectPartId == second.projectPartId
-            && first.arguments == second.arguments
-            && first.compilerMacros == second.compilerMacros
-            && first.includeSearchPaths == second.includeSearchPaths
-            && first.headerPathIds == second.headerPathIds
-            && first.sourcePathIds == second.sourcePathIds;
-    }
-
-    friend bool operator<(const ProjectPartContainer &first, const ProjectPartContainer &second)
-    {
-        return std::tie(first.projectPartId,
-                        first.arguments,
-                        first.compilerMacros,
-                        first.includeSearchPaths,
-                        first.headerPathIds,
-                        first.sourcePathIds)
-             < std::tie(second.projectPartId,
-                        second.arguments,
-                        second.compilerMacros,
-                        first.includeSearchPaths,
-                        second.headerPathIds,
-                        second.sourcePathIds);
-    }
-
-    ProjectPartContainer clone() const
-    {
-        return *this;
-    }
-
-public:
-    Utils::SmallString projectPartId;
-    Utils::SmallStringVector arguments;
-    CompilerMacros compilerMacros;
-    Utils::SmallStringVector includeSearchPaths;
-    FilePathIds headerPathIds;
-    FilePathIds sourcePathIds;
-};
-
-using ProjectPartContainers = std::vector<ProjectPartContainer>;
-
-QDebug operator<<(QDebug debug, const ProjectPartContainer &container);
-} // namespace V2
-} // namespace ClangBackEnd
diff --git a/src/libs/clangsupport/projectpartpch.h b/src/libs/clangsupport/projectpartpch.h
index 6048a0b2f0..a413915b76 100644
--- a/src/libs/clangsupport/projectpartpch.h
+++ b/src/libs/clangsupport/projectpartpch.h
@@ -28,6 +28,7 @@
 #include "clangsupport_global.h"
 
 #include <utils/smallstringio.h>
+#include <filepath.h>
 
 namespace ClangBackEnd {
 
@@ -36,15 +37,16 @@ class ProjectPartPch
 public:
     ProjectPartPch() = default;
     ProjectPartPch(Utils::SmallString &&projectPartId,
-                   Utils::SmallString &&pchPath,
+                   FilePath &&pchPath,
                    long long lastModified)
         : projectPartId(std::move(projectPartId)),
           pchPath(std::move(pchPath)),
           lastModified(lastModified)
     {}
+
     ProjectPartPch(Utils::SmallStringView pchPath,
                    long long lastModified)
-        : pchPath(pchPath),
+        : pchPath(FilePathView(pchPath)),
           lastModified(lastModified)
     {}
 
@@ -78,7 +80,7 @@ public:
 
 public:
     Utils::SmallString projectPartId;
-    Utils::SmallString pchPath;
+    FilePath pchPath;
     long long lastModified = -1;
 };
 
diff --git a/src/libs/clangsupport/refactoringdatabaseinitializer.h b/src/libs/clangsupport/refactoringdatabaseinitializer.h
index 94665409fe..44c23e18a0 100644
--- a/src/libs/clangsupport/refactoringdatabaseinitializer.h
+++ b/src/libs/clangsupport/refactoringdatabaseinitializer.h
@@ -125,7 +125,8 @@ public:
         const Sqlite::Column &projectPartNameColumn = table.addColumn("projectPartName", Sqlite::ColumnType::Text);
         table.addColumn("compilerArguments", Sqlite::ColumnType::Text);
         table.addColumn("compilerMacros", Sqlite::ColumnType::Text);
-        table.addColumn("includeSearchPaths", Sqlite::ColumnType::Text);
+        table.addColumn("systemIncludeSearchPaths", Sqlite::ColumnType::Text);
+        table.addColumn("projectIncludeSearchPaths", Sqlite::ColumnType::Text);
         table.addUniqueIndex({projectPartNameColumn});
 
         table.initialize(database);
diff --git a/src/libs/clangsupport/removeprojectpartsmessage.h b/src/libs/clangsupport/removeprojectpartsmessage.h
index 1f45cc5f52..0aea092fea 100644
--- a/src/libs/clangsupport/removeprojectpartsmessage.h
+++ b/src/libs/clangsupport/removeprojectpartsmessage.h
@@ -25,7 +25,7 @@
 
 #pragma once
 
-#include "projectpartcontainerv2.h"
+#include "projectpartcontainer.h"
 
 namespace ClangBackEnd {
 
diff --git a/src/libs/clangsupport/updateprojectpartsmessage.h b/src/libs/clangsupport/updateprojectpartsmessage.h
index e923d7ba03..b1c6ca1f61 100644
--- a/src/libs/clangsupport/updateprojectpartsmessage.h
+++ b/src/libs/clangsupport/updateprojectpartsmessage.h
@@ -26,7 +26,7 @@
 #pragma once
 
 #include "filecontainerv2.h"
-#include "projectpartcontainerv2.h"
+#include "projectpartcontainer.h"
 
 namespace ClangBackEnd {
 
@@ -34,11 +34,13 @@ class UpdateProjectPartsMessage
 {
 public:
     UpdateProjectPartsMessage() = default;
-    UpdateProjectPartsMessage(V2::ProjectPartContainers &&projectsParts)
+    UpdateProjectPartsMessage(ProjectPartContainers &&projectsParts,
+                              Utils::SmallStringVector &&toolChainArguments)
         : projectsParts(std::move(projectsParts))
+        , toolChainArguments(toolChainArguments)
     {}
 
-    V2::ProjectPartContainers takeProjectsParts()
+    ProjectPartContainers takeProjectsParts()
     {
         return std::move(projectsParts);
     }
@@ -46,6 +48,7 @@ public:
     friend QDataStream &operator<<(QDataStream &out, const UpdateProjectPartsMessage &message)
     {
         out << message.projectsParts;
+        out << message.toolChainArguments;
 
         return out;
     }
@@ -53,6 +56,7 @@ public:
     friend QDataStream &operator>>(QDataStream &in, UpdateProjectPartsMessage &message)
     {
         in >> message.projectsParts;
+        in >> message.toolChainArguments;
 
         return in;
     }
@@ -60,7 +64,8 @@ public:
     friend bool operator==(const UpdateProjectPartsMessage &first,
                            const UpdateProjectPartsMessage &second)
     {
-        return first.projectsParts == second.projectsParts;
+        return first.projectsParts == second.projectsParts
+               && first.toolChainArguments == second.toolChainArguments;
     }
 
     UpdateProjectPartsMessage clone() const
@@ -69,7 +74,8 @@ public:
     }
 
 public:
-    V2::ProjectPartContainers projectsParts;
+    ProjectPartContainers projectsParts;
+    Utils::SmallStringVector toolChainArguments;
 };
 
 CLANGSUPPORT_EXPORT QDebug operator<<(QDebug debug, const UpdateProjectPartsMessage &message);
diff --git a/src/libs/utils/cpplanguage_details.h b/src/libs/utils/cpplanguage_details.h
index 1853d8ed0a..a4defb3262 100644
--- a/src/libs/utils/cpplanguage_details.h
+++ b/src/libs/utils/cpplanguage_details.h
@@ -60,4 +60,16 @@ enum class LanguageExtension : unsigned char {
 
 Q_DECLARE_FLAGS(LanguageExtensions, LanguageExtension)
 
+constexpr enum LanguageExtension operator|(const LanguageExtension first,
+                                           const LanguageExtension second)
+{
+    return static_cast<LanguageExtension>(
+        (static_cast<unsigned char>(first) | static_cast<unsigned char>(second)));
+}
+
+constexpr bool operator&&(const LanguageExtension first, const LanguageExtension second)
+{
+    return static_cast<unsigned char>(first) & static_cast<unsigned char>(second);
+}
+
 } // namespace Utils
diff --git a/src/plugins/clangpchmanager/projectupdater.cpp b/src/plugins/clangpchmanager/projectupdater.cpp
index a2c97c9d14..74b63a8f1a 100644
--- a/src/plugins/clangpchmanager/projectupdater.cpp
+++ b/src/plugins/clangpchmanager/projectupdater.cpp
@@ -36,6 +36,7 @@
 
 #include <cpptools/compileroptionsbuilder.h>
 #include <cpptools/projectpart.h>
+#include <cpptools/headerpathfilter.h>
 
 #include <utils/algorithm.h>
 
@@ -64,10 +65,11 @@ ProjectUpdater::ProjectUpdater(ClangBackEnd::ProjectManagementServerInterface &s
 {
 }
 
-void ProjectUpdater::updateProjectParts(const std::vector<CppTools::ProjectPart *> &projectParts)
+void ProjectUpdater::updateProjectParts(const std::vector<CppTools::ProjectPart *> &projectParts,
+                                        Utils::SmallStringVector &&toolChainArguments)
 {
-    m_server.updateProjectParts(
-                ClangBackEnd::UpdateProjectPartsMessage{toProjectPartContainers(projectParts)});
+    m_server.updateProjectParts(ClangBackEnd::UpdateProjectPartsMessage{
+        toProjectPartContainers(projectParts), std::move(toolChainArguments)});
 }
 
 void ProjectUpdater::removeProjectParts(const QStringList &projectPartIds)
@@ -147,11 +149,21 @@ HeaderAndSources ProjectUpdater::headerAndSourcesFromProjectPart(
     return headerAndSources;
 }
 
-QStringList ProjectUpdater::compilerArguments(CppTools::ProjectPart *projectPart)
+QStringList ProjectUpdater::toolChainArguments(CppTools::ProjectPart *projectPart)
 {
     using CppTools::CompilerOptionsBuilder;
     CompilerOptionsBuilder builder(*projectPart, CppTools::UseSystemHeader::Yes);
-    return builder.build(CppTools::ProjectFile::CXXHeader, CppTools::UsePrecompiledHeaders::No);
+
+    builder.addWordWidth();
+    builder.addPicIfCompilerFlagsContainsIt();
+    builder.addTargetTriple();
+    builder.addExtraCodeModelFlags();
+    builder.undefineClangVersionMacrosForMsvc();
+    builder.undefineCppLanguageFeatureMacrosForMsvc2015();
+    builder.addProjectConfigFileInclude();
+    builder.addMsvcCompatibilityVersion();
+
+    return builder.options();
 }
 
 ClangBackEnd::CompilerMacros ProjectUpdater::createCompilerMacros(const ProjectExplorer::Macros &projectMacros)
@@ -167,43 +179,102 @@ ClangBackEnd::CompilerMacros ProjectUpdater::createCompilerMacros(const ProjectE
     return macros;
 }
 
-Utils::SmallStringVector ProjectUpdater::createIncludeSearchPaths(
-        const ProjectExplorer::HeaderPaths &projectPartHeaderPaths)
+namespace  {
+ClangBackEnd::IncludeSearchPathType convertType(ProjectExplorer::HeaderPathType sourceType)
 {
-    Utils::SmallStringVector includePaths;
-
-    for (const ProjectExplorer::HeaderPath &projectPartHeaderPath : projectPartHeaderPaths) {
-        if (!projectPartHeaderPath.path.isEmpty())
-            includePaths.emplace_back(projectPartHeaderPath.path);
+    using ProjectExplorer::HeaderPathType;
+    using ClangBackEnd::IncludeSearchPathType;
+
+    switch (sourceType) {
+    case HeaderPathType::User:
+        return IncludeSearchPathType::User;
+    case HeaderPathType::System:
+        return IncludeSearchPathType::System;
+    case HeaderPathType::BuiltIn:
+        return IncludeSearchPathType::BuiltIn;
+    case HeaderPathType::Framework:
+        return IncludeSearchPathType::Framework;
     }
 
-    std::sort(includePaths.begin(), includePaths.end());
+    return IncludeSearchPathType::Invalid;
+}
+
+ClangBackEnd::IncludeSearchPaths convertToIncludeSearchPaths(ProjectExplorer::HeaderPaths headerPaths)
+{
+    ClangBackEnd::IncludeSearchPaths paths;
+    paths.reserve(Utils::usize(headerPaths));
+
+    int index = 0;
+    for (const ProjectExplorer::HeaderPath &headerPath : headerPaths)
+        paths.emplace_back(headerPath.path, ++index, convertType(headerPath.type));
+
+    std::sort(paths.begin(), paths.end());
+
+    return paths;
+}
 
-    return includePaths;
+ClangBackEnd::IncludeSearchPaths convertToIncludeSearchPaths(
+    ProjectExplorer::HeaderPaths headerPaths, ProjectExplorer::HeaderPaths headerPaths2)
+{
+    ClangBackEnd::IncludeSearchPaths paths;
+    paths.reserve(Utils::usize(headerPaths) + Utils::usize(headerPaths2));
+
+    int index = 0;
+    for (const ProjectExplorer::HeaderPath &headerPath : headerPaths)
+        paths.emplace_back(headerPath.path, ++index, convertType(headerPath.type));
+
+    for (const ProjectExplorer::HeaderPath &headerPath : headerPaths2)
+        paths.emplace_back(headerPath.path, ++index, convertType(headerPath.type));
+
+    std::sort(paths.begin(), paths.end());
+
+    return paths;
+}
+
+} // namespace
+
+ProjectUpdater::SystemAndProjectIncludeSearchPaths ProjectUpdater::createIncludeSearchPaths(
+    const CppTools::ProjectPart &projectPart)
+{
+    CppTools::HeaderPathFilter filter(projectPart,
+                                      CppTools::UseTweakedHeaderPaths::Yes,
+                                      CLANG_VERSION,
+                                      CLANG_RESOURCE_DIR);
+    filter.process();
+
+    return {convertToIncludeSearchPaths(filter.systemHeaderPaths, filter.builtInHeaderPaths),
+            convertToIncludeSearchPaths(filter.userHeaderPaths)};
 }
 
-ClangBackEnd::V2::ProjectPartContainer ProjectUpdater::toProjectPartContainer(
+ClangBackEnd::ProjectPartContainer ProjectUpdater::toProjectPartContainer(
         CppTools::ProjectPart *projectPart) const
 {
 
-    QStringList arguments = compilerArguments(projectPart);
+    QStringList arguments = toolChainArguments(projectPart);
 
     HeaderAndSources headerAndSources = headerAndSourcesFromProjectPart(projectPart);
 
-    return ClangBackEnd::V2::ProjectPartContainer(projectPart->id(),
-                                                  Utils::SmallStringVector(arguments),
-                                                  createCompilerMacros(projectPart->projectMacros),
-                                                  createIncludeSearchPaths(projectPart->headerPaths),
-                                                  std::move(headerAndSources.headers),
-                                                  std::move(headerAndSources.sources));
+    auto includeSearchPaths = createIncludeSearchPaths(*projectPart);
+
+    return ClangBackEnd::ProjectPartContainer(projectPart->id(),
+                                              Utils::SmallStringVector(arguments),
+                                              createCompilerMacros(projectPart->projectMacros),
+                                              std::move(includeSearchPaths.system),
+                                              std::move(includeSearchPaths.project),
+                                              std::move(headerAndSources.headers),
+                                              std::move(headerAndSources.sources),
+                                              projectPart->language,
+                                              projectPart->languageVersion,
+                                              static_cast<Utils::LanguageExtension>(
+                                                  int(projectPart->languageExtensions)));
 }
 
-std::vector<ClangBackEnd::V2::ProjectPartContainer> ProjectUpdater::toProjectPartContainers(
+ClangBackEnd::ProjectPartContainers ProjectUpdater::toProjectPartContainers(
         std::vector<CppTools::ProjectPart *> projectParts) const
 {
     using namespace std::placeholders;
 
-    std::vector<ClangBackEnd::V2::ProjectPartContainer> projectPartContainers;
+    std::vector<ClangBackEnd::ProjectPartContainer> projectPartContainers;
     projectPartContainers.reserve(projectParts.size());
 
     std::transform(projectParts.begin(),
diff --git a/src/plugins/clangpchmanager/projectupdater.h b/src/plugins/clangpchmanager/projectupdater.h
index fd4ff95538..896a02def0 100644
--- a/src/plugins/clangpchmanager/projectupdater.h
+++ b/src/plugins/clangpchmanager/projectupdater.h
@@ -31,6 +31,8 @@
 #include <filecontainerv2.h>
 #include <filepathcachinginterface.h>
 #include <generatedfiles.h>
+#include <includesearchpath.h>
+#include <projectpartcontainer.h>
 
 #include <projectexplorer/headerpath.h>
 
@@ -46,10 +48,6 @@ class ProjectFile;
 
 namespace ClangBackEnd {
 class ProjectManagementServerInterface;
-
-namespace V2 {
-class ProjectPartContainer;
-}
 }
 
 QT_FORWARD_DECLARE_CLASS(QStringList)
@@ -64,33 +62,39 @@ class PchManagerClient;
 class CLANGPCHMANAGER_EXPORT ProjectUpdater
 {
 public:
+    struct SystemAndProjectIncludeSearchPaths
+    {
+        ClangBackEnd::IncludeSearchPaths system;
+        ClangBackEnd::IncludeSearchPaths project;
+    };
+
     ProjectUpdater(ClangBackEnd::ProjectManagementServerInterface &server,
                    ClangBackEnd::FilePathCachingInterface &filePathCache);
 
-    void updateProjectParts(const std::vector<CppTools::ProjectPart *> &projectParts);
+    void updateProjectParts(const std::vector<CppTools::ProjectPart *> &projectParts,
+                            Utils::SmallStringVector &&toolChainArguments);
     void removeProjectParts(const QStringList &projectPartIds);
 
     void updateGeneratedFiles(ClangBackEnd::V2::FileContainers &&generatedFiles);
     void removeGeneratedFiles(ClangBackEnd::FilePaths &&filePaths);
 
-unittest_public:
     void setExcludedPaths(ClangBackEnd::FilePaths &&excludedPaths);
     const ClangBackEnd::FilePaths &excludedPaths() const;
 
     const ClangBackEnd::GeneratedFiles &generatedFiles() const;
 
     HeaderAndSources headerAndSourcesFromProjectPart(CppTools::ProjectPart *projectPart) const;
-    ClangBackEnd::V2::ProjectPartContainer toProjectPartContainer(
+    ClangBackEnd::ProjectPartContainer toProjectPartContainer(
             CppTools::ProjectPart *projectPart) const;
-    std::vector<ClangBackEnd::V2::ProjectPartContainer> toProjectPartContainers(
+    ClangBackEnd::ProjectPartContainers toProjectPartContainers(
             std::vector<CppTools::ProjectPart *> projectParts) const;
     void addToHeaderAndSources(HeaderAndSources &headerAndSources,
                                const CppTools::ProjectFile &projectFile) const;
-    static QStringList compilerArguments(CppTools::ProjectPart *projectPart);
+    static QStringList toolChainArguments(CppTools::ProjectPart *projectPart);
     static ClangBackEnd::CompilerMacros createCompilerMacros(
             const ProjectExplorer::Macros &projectMacros);
-    static Utils::SmallStringVector createIncludeSearchPaths(
-            const ProjectExplorer::HeaderPaths &projectPartHeaderPaths);
+    static SystemAndProjectIncludeSearchPaths createIncludeSearchPaths(
+        const CppTools::ProjectPart &projectPart);
     static ClangBackEnd::FilePaths createExcludedPaths(
             const ClangBackEnd::V2::FileContainers &generatedFiles);
 
diff --git a/src/plugins/clangpchmanager/qtcreatorprojectupdater.h b/src/plugins/clangpchmanager/qtcreatorprojectupdater.h
index 9be66f1444..9521475692 100644
--- a/src/plugins/clangpchmanager/qtcreatorprojectupdater.h
+++ b/src/plugins/clangpchmanager/qtcreatorprojectupdater.h
@@ -71,7 +71,8 @@ public:
 
     void projectPartsUpdated(ProjectExplorer::Project *project)
     {
-        ProjectUpdaterType::updateProjectParts(Internal::createProjectParts(project));
+
+        ProjectUpdaterType::updateProjectParts(Internal::createProjectParts(project), {}); // TODO add support for toolchainarguments
     }
 
     void projectPartsRemoved(const QStringList &projectPartIds)
diff --git a/src/plugins/clangrefactoring/refactoringprojectupdater.cpp b/src/plugins/clangrefactoring/refactoringprojectupdater.cpp
index 648e458fd5..99b028e522 100644
--- a/src/plugins/clangrefactoring/refactoringprojectupdater.cpp
+++ b/src/plugins/clangrefactoring/refactoringprojectupdater.cpp
@@ -35,7 +35,7 @@ void RefactoringProjectUpdater::precompiledHeaderUpdated(const QString &projectP
 {
     auto projectPart = m_cppModelManager.projectPartForId(projectPartId);
     if (projectPart)
-        updateProjectParts({projectPart.data()});
+        updateProjectParts({projectPart.data()}, {});
 }
 
 void RefactoringProjectUpdater::precompiledHeaderRemoved(const QString &projectPartId)
diff --git a/src/plugins/cpptools/compileroptionsbuilder.cpp b/src/plugins/cpptools/compileroptionsbuilder.cpp
index c721946593..c3b8f115f2 100644
--- a/src/plugins/cpptools/compileroptionsbuilder.cpp
+++ b/src/plugins/cpptools/compileroptionsbuilder.cpp
@@ -249,6 +249,12 @@ void CompilerOptionsBuilder::addExtraCodeModelFlags()
     add(m_projectPart.extraCodeModelFlags);
 }
 
+void CompilerOptionsBuilder::addPicIfCompilerFlagsContainsIt()
+{
+    if (m_projectPart.compilerFlags.contains("-fPIC"))
+        add("-fPIC");
+}
+
 void CompilerOptionsBuilder::addCompilerFlags()
 {
     add(m_compilerFlags.flags);
diff --git a/src/plugins/cpptools/compileroptionsbuilder.h b/src/plugins/cpptools/compileroptionsbuilder.h
index 64c07b5fa3..0d0ca84488 100644
--- a/src/plugins/cpptools/compileroptionsbuilder.h
+++ b/src/plugins/cpptools/compileroptionsbuilder.h
@@ -63,6 +63,7 @@ public:
 
     void addTargetTriple();
     void addExtraCodeModelFlags();
+    void addPicIfCompilerFlagsContainsIt();
     void addCompilerFlags();
     void insertWrappedQtHeaders();
     void addLanguageVersionAndExtensions();
diff --git a/src/plugins/cpptools/cppprojectinfogenerator.cpp b/src/plugins/cpptools/cppprojectinfogenerator.cpp
index 29c251bdd4..c177c7a7d9 100644
--- a/src/plugins/cpptools/cppprojectinfogenerator.cpp
+++ b/src/plugins/cpptools/cppprojectinfogenerator.cpp
@@ -164,6 +164,7 @@ ProjectPart::Ptr ProjectInfoGenerator::createProjectPart(
     part->extraCodeModelFlags = tcInfo.extraCodeModelFlags;
     part->compilerFlags = flags.commandLineFlags;
     part->warningFlags = flags.warningFlags;
+    part->language = language;
     part->languageExtensions = flags.languageExtensions;
 
     // Toolchain macros and language version
diff --git a/src/plugins/cpptools/projectpart.h b/src/plugins/cpptools/projectpart.h
index bd5fbee764..e357db3a3d 100644
--- a/src/plugins/cpptools/projectpart.h
+++ b/src/plugins/cpptools/projectpart.h
@@ -39,6 +39,8 @@
 
 #include <cplusplus/Token.h>
 
+#include <utils/cpplanguage_details.h>
+
 #include <QString>
 #include <QSharedPointer>
 
@@ -91,6 +93,7 @@ public:
     QString callGroupId;
 
     // Versions, features and extensions
+    ::Utils::Language language = Utils::Language::Cxx;
     ::Utils::LanguageVersion languageVersion = ::Utils::LanguageVersion::LatestCxx;
     ::Utils::LanguageExtensions languageExtensions = ::Utils::LanguageExtension::None;
     CPlusPlus::LanguageFeatures languageFeatures;
diff --git a/src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp b/src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp
index db4dc76aaa..4e2b19db8b 100644
--- a/src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp
+++ b/src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp
@@ -23,18 +23,24 @@
 **
 ****************************************************************************/
 
+#include <builddependenciesprovider.h>
+#include <builddependenciesstorage.h>
+#include <builddependencycollector.h>
 #include <clangpathwatcher.h>
 #include <connectionserver.h>
 #include <environment.h>
 #include <generatedfiles.h>
+#include <modifiedtimechecker.h>
 #include <pchcreator.h>
 #include <pchmanagerserver.h>
 #include <pchmanagerclientproxy.h>
+#include <pchtaskgenerator.h>
+#include <pchtaskqueue.h>
+#include <pchtasksmerger.h>
 #include <precompiledheaderstorage.h>
 #include <processormanager.h>
 #include <progresscounter.h>
 #include <projectparts.h>
-#include <projectpartqueue.h>
 #include <filepathcaching.h>
 #include <refactoringdatabaseinitializer.h>
 #include <sqlitedatabase.h>
@@ -42,12 +48,12 @@
 
 #include <QCommandLineParser>
 #include <QCoreApplication>
+#include <QDateTime>
 #include <QFileSystemWatcher>
 #include <QLoggingCategory>
 #include <QProcess>
 #include <QTemporaryDir>
 #include <QTimer>
-
 #include <chrono>
 #include <thread>
 
@@ -62,6 +68,8 @@ using ClangBackEnd::PchManagerServer;
 using ClangBackEnd::PrecompiledHeaderStorage;
 using ClangBackEnd::ProjectParts;
 using ClangBackEnd::FilePathCache;
+using ClangBackEnd::FilePathView;
+using ClangBackEnd::TimeStamp;
 
 class PchManagerApplication final : public QCoreApplication
 {
@@ -93,11 +101,6 @@ public:
         return m_pchBuildDirectoryPath;
     }
 
-    QString clangCompilerPath() const override
-    {
-        return QString(CLANG_COMPILER_PATH);
-    }
-
     uint hardwareConcurrency() const override
     {
         return std::thread::hardware_concurrency();
@@ -132,13 +135,11 @@ public:
     PchCreatorManager(const ClangBackEnd::GeneratedFiles &generatedFiles,
                       ClangBackEnd::Environment &environment,
                       Sqlite::Database &database,
-                      PchManagerServer &pchManagerServer,
-                      ClangBackEnd::ClangPathWatcherInterface &fileSystemWatcher)
+                      PchManagerServer &pchManagerServer)
         : ProcessorManager(generatedFiles),
           m_environment(environment),
           m_database(database),
-          m_pchManagerServer(pchManagerServer),
-          m_fileSystemWatcher(fileSystemWatcher)
+          m_pchManagerServer(pchManagerServer)
     {}
 
 protected:
@@ -146,25 +147,22 @@ protected:
     {
         return std::make_unique<PchCreator>(m_environment,
                                             m_database,
-                                            *m_pchManagerServer.client(),
-                                            m_fileSystemWatcher);
+                                            *m_pchManagerServer.client());
     }
 
 private:
     ClangBackEnd::Environment &m_environment;
     Sqlite::Database &m_database;
     ClangBackEnd::PchManagerServer &m_pchManagerServer;
-    ClangBackEnd::ClangPathWatcherInterface &m_fileSystemWatcher;
 };
 
 struct Data // because we have a cycle dependency
 {
-    using TaskScheduler = ClangBackEnd::TaskScheduler<PchCreatorManager, ClangBackEnd::ProjectPartQueue::Task>;
+    using TaskScheduler = ClangBackEnd::TaskScheduler<PchCreatorManager, ClangBackEnd::PchTaskQueue::Task>;
 
-    Data(const QString &databasePath,
-         const QString &pchsPath)
-        : database{Utils::PathString{databasePath}, 100000ms},
-          environment{pchsPath}
+    Data(const QString &databasePath, const QString &pchsPath)
+        : database{Utils::PathString{databasePath}, 100000ms}
+        , environment{pchsPath}
     {}
     Sqlite::Database database;
     ClangBackEnd::RefactoringDatabaseInitializer<Sqlite::Database> databaseInitializer{database};
@@ -173,12 +171,39 @@ struct Data // because we have a cycle dependency
     ApplicationEnvironment environment;
     ProjectParts projectParts;
     GeneratedFiles generatedFiles;
-    PchCreatorManager pchCreatorManager{generatedFiles, environment, database, clangPchManagerServer, includeWatcher};
+    PchCreatorManager pchCreatorManager{generatedFiles, environment, database, clangPchManagerServer};
     PrecompiledHeaderStorage<> preCompiledHeaderStorage{database};
-    ClangBackEnd::ProgressCounter progressCounter{[&] (int progress, int total) { clangPchManagerServer.setProgress(progress, total); }};
-    TaskScheduler taskScheduler{pchCreatorManager, projectPartQueue, progressCounter, std::thread::hardware_concurrency()};
-    ClangBackEnd::ProjectPartQueue projectPartQueue{taskScheduler, preCompiledHeaderStorage, database, progressCounter};
-    PchManagerServer clangPchManagerServer{includeWatcher, projectPartQueue, projectParts, generatedFiles};
+    ClangBackEnd::ProgressCounter progressCounter{
+        [&](int progress, int total) { clangPchManagerServer.setProgress(progress, total); }};
+    TaskScheduler systemTaskScheduler{pchCreatorManager,
+                                      pchTaskQueue,
+                                      progressCounter,
+                                      std::thread::hardware_concurrency(),
+                                      ClangBackEnd::CallDoInMainThreadAfterFinished::No};
+    TaskScheduler projectTaskScheduler{pchCreatorManager,
+                                       pchTaskQueue,
+                                       progressCounter,
+                                       std::thread::hardware_concurrency(),
+                                       ClangBackEnd::CallDoInMainThreadAfterFinished::Yes};
+    ClangBackEnd::PchTaskQueue pchTaskQueue{systemTaskScheduler,
+                                            projectTaskScheduler,
+                                            progressCounter,
+                                            preCompiledHeaderStorage,
+                                            database};
+    ClangBackEnd::PchTasksMerger pchTaskMerger{pchTaskQueue};
+    ClangBackEnd::BuildDependenciesStorage<> buildDependencyStorage{database};
+    ClangBackEnd::BuildDependencyCollector buildDependencyCollector{filePathCache};
+    std::function<TimeStamp(FilePathView filePath)> getModifiedTime{
+        [&](ClangBackEnd::FilePathView path) -> TimeStamp {
+            return QFileInfo(QString(path)).lastModified().toSecsSinceEpoch();
+        }};
+    ClangBackEnd::ModifiedTimeChecker modifiedTimeChecker{getModifiedTime, filePathCache};
+    ClangBackEnd::BuildDependenciesProvider buildDependencyProvider{buildDependencyStorage,
+                                                                    modifiedTimeChecker,
+                                                                    buildDependencyCollector,
+                                                                    database};
+    ClangBackEnd::PchTaskGenerator pchTaskGenerator{buildDependencyProvider, pchTaskMerger};
+    PchManagerServer clangPchManagerServer{includeWatcher, pchTaskGenerator, projectParts, generatedFiles};
 };
 
 int main(int argc, char *argv[])
diff --git a/src/tools/clangpchmanagerbackend/source/builddependenciesprovider.cpp b/src/tools/clangpchmanagerbackend/source/builddependenciesprovider.cpp
index 7f97599fac..d58da0f27c 100644
--- a/src/tools/clangpchmanagerbackend/source/builddependenciesprovider.cpp
+++ b/src/tools/clangpchmanagerbackend/source/builddependenciesprovider.cpp
@@ -53,7 +53,7 @@ OutputContainer setUnion(InputContainer1 &&input1,
     return results;
 }
 
-BuildDependency BuildDependenciesProvider::create(const V2::ProjectPartContainer &projectPart)
+BuildDependency BuildDependenciesProvider::create(const ProjectPartContainer &projectPart)
 {
     SourceEntries includes = createSourceEntriesFromStorage(projectPart.sourcePathIds,
                                                             projectPart.projectPartId);
diff --git a/src/tools/clangpchmanagerbackend/source/builddependenciesprovider.h b/src/tools/clangpchmanagerbackend/source/builddependenciesprovider.h
index 386eca587e..4a89ace732 100644
--- a/src/tools/clangpchmanagerbackend/source/builddependenciesprovider.h
+++ b/src/tools/clangpchmanagerbackend/source/builddependenciesprovider.h
@@ -50,7 +50,7 @@ public:
         , m_transactionBackend(transactionBackend)
     {}
 
-    BuildDependency create(const V2::ProjectPartContainer &projectPart) override;
+    BuildDependency create(const ProjectPartContainer &projectPart) override;
 
 private:
     BuildDependency createBuildDependencyFromStorage(SourceEntries &&includes) const;
diff --git a/src/tools/clangpchmanagerbackend/source/builddependenciesproviderinterface.h b/src/tools/clangpchmanagerbackend/source/builddependenciesproviderinterface.h
index 0bfaeed06c..7af8c054cc 100644
--- a/src/tools/clangpchmanagerbackend/source/builddependenciesproviderinterface.h
+++ b/src/tools/clangpchmanagerbackend/source/builddependenciesproviderinterface.h
@@ -27,14 +27,14 @@
 
 #include "builddependency.h"
 
-#include "projectpartcontainerv2.h"
+#include "projectpartcontainer.h"
 
 namespace ClangBackEnd {
 
 class BuildDependenciesProviderInterface
 {
 public:
-    virtual BuildDependency create(const V2::ProjectPartContainer &projectPart) = 0;
+    virtual BuildDependency create(const ProjectPartContainer &projectPart) = 0;
 
 protected:
     ~BuildDependenciesProviderInterface() = default;
diff --git a/src/tools/clangpchmanagerbackend/source/builddependencycollector.cpp b/src/tools/clangpchmanagerbackend/source/builddependencycollector.cpp
index 4ba3e8c0e6..bfbfbf20cd 100644
--- a/src/tools/clangpchmanagerbackend/source/builddependencycollector.cpp
+++ b/src/tools/clangpchmanagerbackend/source/builddependencycollector.cpp
@@ -26,6 +26,7 @@
 #include "builddependencycollector.h"
 
 #include "collectbuilddependencytoolaction.h"
+#include "commandlinebuilder.h"
 
 #include <utils/smallstring.h>
 
@@ -44,9 +45,12 @@ FilePathIds operator+(const FilePathIds &first, const FilePathIds &second)
 }
 }
 
-BuildDependency BuildDependencyCollector::create(const V2::ProjectPartContainer &projectPart)
+BuildDependency BuildDependencyCollector::create(const ProjectPartContainer &projectPart)
 {
-    addFiles(projectPart.sourcePathIds, projectPart.arguments);
+    CommandLineBuilder<ProjectPartContainer, Utils::SmallStringVector> builder{
+        projectPart, projectPart.toolChainArguments};
+
+    addFiles(projectPart.sourcePathIds, builder.commandLine);
 
     setExcludedFilePaths(
         m_filePathCache.filePaths(projectPart.headerPathIds + projectPart.sourcePathIds));
diff --git a/src/tools/clangpchmanagerbackend/source/builddependencycollector.h b/src/tools/clangpchmanagerbackend/source/builddependencycollector.h
index cab749c316..2ea7fb7c90 100644
--- a/src/tools/clangpchmanagerbackend/source/builddependencycollector.h
+++ b/src/tools/clangpchmanagerbackend/source/builddependencycollector.h
@@ -42,7 +42,7 @@ public:
     {
     }
 
-    BuildDependency create(const V2::ProjectPartContainer &projectPart) override;
+    BuildDependency create(const ProjectPartContainer &projectPart) override;
 
     void collect();
 
diff --git a/src/tools/clangpchmanagerbackend/source/builddependencygeneratorinterface.h b/src/tools/clangpchmanagerbackend/source/builddependencygeneratorinterface.h
index f6e13f3a1a..0c368e7e25 100644
--- a/src/tools/clangpchmanagerbackend/source/builddependencygeneratorinterface.h
+++ b/src/tools/clangpchmanagerbackend/source/builddependencygeneratorinterface.h
@@ -27,14 +27,14 @@
 
 #include "builddependency.h"
 
-#include "projectpartcontainerv2.h"
+#include "projectpartcontainer.h"
 
 namespace ClangBackEnd {
 
 class BuildDependencyGeneratorInterface
 {
 public:
-    virtual BuildDependency create(const V2::ProjectPartContainer &projectPart) = 0;
+    virtual BuildDependency create(const ProjectPartContainer &projectPart) = 0;
 
 protected:
     ~BuildDependencyGeneratorInterface() = default;
diff --git a/src/tools/clangpchmanagerbackend/source/clangpchmanagerbackend-source.pri b/src/tools/clangpchmanagerbackend/source/clangpchmanagerbackend-source.pri
index 693e110402..fa8d6e527a 100644
--- a/src/tools/clangpchmanagerbackend/source/clangpchmanagerbackend-source.pri
+++ b/src/tools/clangpchmanagerbackend/source/clangpchmanagerbackend-source.pri
@@ -4,7 +4,6 @@ SOURCES += \
     $$PWD/builddependenciesprovider.cpp \
     $$PWD/pchmanagerserver.cpp \
     $$PWD/projectparts.cpp \
-    $$PWD/projectpartqueue.cpp \
     $$PWD/pchtaskgenerator.cpp \
     $$PWD/pchtasksmerger.cpp \
     $$PWD/pchtaskqueue.cpp
@@ -17,9 +16,7 @@ HEADERS += \
     $$PWD/projectparts.h \
     $$PWD/pchcreatorinterface.h \
     $$PWD/projectpartsinterface.h \
-    $$PWD/projectpartqueue.h \
     $$PWD/queueinterface.h \
-    $$PWD/projectpartqueueinterface.h \
     $$PWD/processormanagerinterface.h \
     $$PWD/processorinterface.h \
     $$PWD/taskscheduler.h \
@@ -40,7 +37,11 @@ HEADERS += \
     $$PWD/pchtasksmergerinterface.h \
     $$PWD/pchtasksmerger.h \
     $$PWD/pchtaskqueueinterface.h \
-    $$PWD/pchtaskqueue.h
+    $$PWD/pchtaskqueue.h \
+    $$PWD/generatepchactionfactory.h \
+    $$PWD/pchtaskgeneratorinterface.h \
+    $$PWD/toolchainargumentscache.h \
+    $$PWD/modifiedtimechecker.h
 
 !isEmpty(LIBTOOLING_LIBS) {
 SOURCES += \
diff --git a/src/tools/clangpchmanagerbackend/source/environment.h b/src/tools/clangpchmanagerbackend/source/environment.h
index a7deea2b80..7f575fe169 100644
--- a/src/tools/clangpchmanagerbackend/source/environment.h
+++ b/src/tools/clangpchmanagerbackend/source/environment.h
@@ -37,7 +37,6 @@ public:
     Environment &operator=(const Environment &) = delete;
 
     virtual QString pchBuildDirectory() const = 0;
-    virtual QString clangCompilerPath() const = 0;
     virtual uint hardwareConcurrency() const = 0;
 
 protected:
diff --git a/src/tools/clangpchmanagerbackend/source/generatepchactionfactory.h b/src/tools/clangpchmanagerbackend/source/generatepchactionfactory.h
new file mode 100644
index 0000000000..47a64eda92
--- /dev/null
+++ b/src/tools/clangpchmanagerbackend/source/generatepchactionfactory.h
@@ -0,0 +1,41 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include <clang/Tooling/Tooling.h>
+
+#include "clang/Frontend/FrontendActions.h"
+
+namespace ClangBackEnd {
+class GeneratePCHActionFactory final : public clang::tooling::FrontendActionFactory
+{
+public:
+    clang::FrontendAction *create() override
+    {
+        return new clang::GeneratePCHAction;
+    }
+};
+} // namespace ClangBackEnd
diff --git a/src/tools/clangpchmanagerbackend/source/modifiedtimechecker.h b/src/tools/clangpchmanagerbackend/source/modifiedtimechecker.h
new file mode 100644
index 0000000000..9e67a27b14
--- /dev/null
+++ b/src/tools/clangpchmanagerbackend/source/modifiedtimechecker.h
@@ -0,0 +1,149 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include "modifiedtimecheckerinterface.h"
+
+#include <filepathcachinginterface.h>
+
+#include <algorithm>
+#include <iterator>
+
+namespace ClangBackEnd {
+
+class ModifiedTimeChecker final : public ModifiedTimeCheckerInterface
+{
+public:
+    using GetModifiedTime = std::function<ClangBackEnd::TimeStamp(ClangBackEnd::FilePathView filePath)>;
+    ModifiedTimeChecker(GetModifiedTime &getModifiedTime, FilePathCachingInterface &filePathCache)
+        : m_getModifiedTime(getModifiedTime)
+        , m_filePathCache(filePathCache)
+    {}
+
+    bool isUpToDate(const SourceEntries &sourceEntries) const
+    {
+        if (sourceEntries.empty())
+            return false;
+
+        updateCurrentSourceTimeStamps(sourceEntries);
+
+        return compareEntries(sourceEntries);
+    }
+
+    void pathsChanged(const FilePathIds &filePathIds)
+    {
+        using SourceTimeStampPointers = std::vector<SourceTimeStamp*>;
+
+        class BackInserterIterator : public std::back_insert_iterator<SourceTimeStampPointers>
+        {
+        public:
+            BackInserterIterator(SourceTimeStampPointers &container)
+                : std::back_insert_iterator<SourceTimeStampPointers>(container)
+            {}
+
+            BackInserterIterator &operator=(SourceTimeStamp &timeStamp)
+            {
+                container->push_back(&timeStamp);
+
+                return *this;
+            }
+
+            BackInserterIterator &operator*() { return *this; }
+        };
+
+        SourceTimeStampPointers timeStampsToUpdate;
+        timeStampsToUpdate.reserve(filePathIds.size());
+
+        std::set_intersection(m_currentSourceTimeStamps.begin(),
+                              m_currentSourceTimeStamps.end(),
+                              filePathIds.begin(),
+                              filePathIds.end(),
+                              BackInserterIterator(timeStampsToUpdate));
+
+        for (SourceTimeStamp *sourceTimeStamp : timeStampsToUpdate) {
+            sourceTimeStamp->lastModified = m_getModifiedTime(
+                m_filePathCache.filePath(sourceTimeStamp->sourceId));
+        }
+    }
+
+private:
+    bool compareEntries(const SourceEntries &sourceEntries) const
+    {
+        SourceTimeStamps currentSourceTimeStamp;
+        currentSourceTimeStamp.reserve(sourceEntries.size());
+        std::set_intersection(m_currentSourceTimeStamps.begin(),
+                              m_currentSourceTimeStamps.end(),
+                              sourceEntries.begin(),
+                              sourceEntries.end(),
+                              std::back_inserter(currentSourceTimeStamp));
+
+        return std::equal(currentSourceTimeStamp.begin(),
+                          currentSourceTimeStamp.end(),
+                          sourceEntries.begin(),
+                          sourceEntries.end(),
+                          [](SourceTimeStamp first, SourceTimeStamp second) {
+                              return first.lastModified <= second.lastModified;
+                          });
+    }
+
+    void updateCurrentSourceTimeStamps(const SourceEntries &sourceEntries) const
+    {
+        SourceTimeStamps sourceTimeStamps = newSourceTimeStamps(sourceEntries);
+
+        for (SourceTimeStamp &newSourceTimeStamp : sourceTimeStamps) {
+            newSourceTimeStamp.lastModified = m_getModifiedTime(
+                m_filePathCache.filePath(newSourceTimeStamp.sourceId));
+        }
+
+        auto split = sourceTimeStamps.insert(sourceTimeStamps.end(),
+                                        m_currentSourceTimeStamps.begin(),
+                                        m_currentSourceTimeStamps.end());
+        std::inplace_merge(sourceTimeStamps.begin(), split, sourceTimeStamps.end());
+
+        m_currentSourceTimeStamps = sourceTimeStamps;
+    }
+
+    SourceTimeStamps newSourceTimeStamps(const SourceEntries &sourceEntries) const
+    {
+        SourceTimeStamps newTimeStamps;
+        newTimeStamps.reserve(sourceEntries.size() + m_currentSourceTimeStamps.size());
+
+        std::set_difference(sourceEntries.begin(),
+                            sourceEntries.end(),
+                            m_currentSourceTimeStamps.begin(),
+                            m_currentSourceTimeStamps.end(),
+                            std::back_inserter(newTimeStamps));
+
+        return newTimeStamps;
+    }
+
+private:
+    mutable SourceTimeStamps m_currentSourceTimeStamps;
+    GetModifiedTime &m_getModifiedTime;
+    FilePathCachingInterface &m_filePathCache;
+};
+
+} // namespace ClangBackEnd
diff --git a/src/tools/clangpchmanagerbackend/source/pchcreator.cpp b/src/tools/clangpchmanagerbackend/source/pchcreator.cpp
index 79062b5e2d..ea9d7c3e37 100644
--- a/src/tools/clangpchmanagerbackend/source/pchcreator.cpp
+++ b/src/tools/clangpchmanagerbackend/source/pchcreator.cpp
@@ -25,8 +25,10 @@
 
 #include "pchcreator.h"
 
-#include "environment.h"
 #include "builddependencycollector.h"
+#include "commandlinebuilder.h"
+#include "environment.h"
+#include "generatepchactionfactory.h"
 #include "pchnotcreatederror.h"
 
 #include <clangpathwatcherinterface.h>
@@ -45,41 +47,6 @@
 namespace ClangBackEnd {
 
 namespace {
-template <typename Source,
-          typename Target>
-void append(Target &target, const Source &source)
-{
-    using ValueType = typename Target::value_type;
-    Source clonedSource = source.clone();
-
-    target.reserve(target.size() + source.size());
-
-    for (auto &&entry : clonedSource)
-        target.push_back(ValueType(std::move(entry)));
-}
-
-void appendFilePathId(ClangBackEnd::FilePaths &target,
-                      const ClangBackEnd::FilePathIds &source,
-                      const ClangBackEnd::FilePathCachingInterface &filePathCache)
-{
-    for (FilePathId id : source)
-        target.emplace_back(filePathCache.filePath(id));
-}
-
-Utils::PathStringVector generatedFilePaths(const V2::FileContainers &generaredFiles)
-{
-    Utils::PathStringVector generaredFilePaths;
-    generaredFilePaths.reserve(generaredFiles.size());
-
-    for (const V2::FileContainer &generatedFile : generaredFiles)
-        generaredFilePaths.push_back(generatedFile.filePath.path());
-
-    return generaredFilePaths;
-}
-
-}
-
-namespace {
 
 std::size_t contentSize(const FilePaths &includes)
 {
@@ -106,239 +73,72 @@ Utils::SmallString PchCreator::generatePchIncludeFileContent(const FilePathIds &
 }
 
 
-bool PchCreator::generatePch(Utils::SmallStringVector &&compilerArguments)
-{
-    QProcess process;
-
-    process.setProcessChannelMode(QProcess::ForwardedChannels);
-    process.setArguments(QStringList(compilerArguments));
-    process.setProgram(QString(m_environment.clangCompilerPath()));
-
-    process.start();
-    process.waitForFinished(300000);
-
-    return process.exitStatus() == QProcess::NormalExit && process.exitCode() == 0;
-}
-
-QStringList PchCreator::convertToQStringList(const Utils::SmallStringVector &compilerArguments)
-{
-    QStringList qStringList;
-
-    append(qStringList, compilerArguments);
-
-    return qStringList;
-}
-
-namespace {
-
-void hashProjectPart(QCryptographicHash &hash, const V2::ProjectPartContainer &projectPart)
-{
-    const auto &projectPartId = projectPart.projectPartId;
-    hash.addData(projectPartId.data(), int(projectPartId.size()));
-
-    for (const auto &argument : projectPart.arguments)
-        hash.addData(argument.data(), int(argument.size()));
-}
-}
-
-Utils::SmallStringVector PchCreator::generateProjectPartCommandLine(
-        const V2::ProjectPartContainer &projectPart) const
-{
-    const Utils::SmallStringVector &arguments = projectPart.arguments;
-
-    Utils::SmallStringVector commandLine;
-    commandLine.reserve(arguments.size() + 1);
-
-    commandLine.emplace_back(m_environment.clangCompilerPath());
-
-    append(commandLine , arguments);
-
-    return commandLine;
-}
-
-Utils::SmallString PchCreator::generateProjectPartPchFilePathWithoutExtension(
-        const V2::ProjectPartContainer &projectPart) const
-{
-    QByteArray fileName = m_environment.pchBuildDirectory().toUtf8();
-    fileName += '/';
-    fileName += projectPartHash(projectPart);
-
-    return Utils::SmallString::fromQByteArray(fileName);
-}
-
-Utils::PathStringVector PchCreator::generateProjectPartHeaders(
-        const V2::ProjectPartContainer &projectPart) const
-{
-   Utils::PathStringVector headerPaths;
-   headerPaths.reserve(projectPart.headerPathIds.size() + m_unsavedFiles.size());
-
-   std::transform(projectPart.headerPathIds.begin(),
-                  projectPart.headerPathIds.end(),
-                  std::back_inserter(headerPaths),
-                  [&] (FilePathId filePathId) {
-       return m_filePathCache.filePath(filePathId);
-   });
-
-   Utils::PathStringVector generatedPath = generatedFilePaths(m_unsavedFiles);
-
-   std::copy(std::make_move_iterator(generatedPath.begin()),
-             std::make_move_iterator(generatedPath.end()),
-             std::back_inserter(headerPaths));
-
-   return headerPaths;
-}
-
-namespace {
-
-std::size_t sizeOfContent(const ClangBackEnd::FilePaths &paths)
-{
-    return std::accumulate(paths.begin(),
-                           paths.end(),
-                           std::size_t(0),
-                           [] (std::size_t size, const auto &path) {
-        const char includeTemplate[] = "#include \"\"\n";
-        return size + path.size() + sizeof(includeTemplate);
-    });
-}
-
-Utils::SmallString concatContent(const ClangBackEnd::FilePaths &paths, std::size_t size)
-{
-    Utils::SmallString content;
-    content.reserve(size);
-
-    for (const ClangBackEnd::FilePath &path : paths) {
-        content += "#include \"";
-        content +=  path;
-        content += "\"\n";
-    };
-
-    return content;
-}
-
-}
-
-Utils::SmallString PchCreator::generateProjectPartSourcesContent(
-        const V2::ProjectPartContainer &projectPart) const
-{
-    ClangBackEnd::FilePaths paths = generateProjectPartSourcePaths(projectPart);
-
-    return concatContent(paths, sizeOfContent(paths));
-}
-
-ClangBackEnd::FilePaths PchCreator::generateProjectPartSourcePaths(
-    const V2::ProjectPartContainer &projectPart) const
-{
-    ClangBackEnd::FilePaths includeAndSources;
-    includeAndSources.reserve(projectPart.sourcePathIds.size());
-
-    appendFilePathId(includeAndSources, projectPart.sourcePathIds, m_filePathCache);
-
-    return includeAndSources;
-}
-
-SourceEntries PchCreator::generateProjectPartPchIncludes(
-        const V2::ProjectPartContainer &projectPart) const
+bool PchCreator::generatePch()
 {
-    Utils::SmallString jointedFileContent = generateProjectPartSourcesContent(projectPart);
-    Utils::SmallString jointedFilePath = generateProjectPartSourceFilePath(projectPart);
-    auto jointFile = generateFileWithContent(jointedFilePath, jointedFileContent);
-    Utils::SmallStringVector arguments = generateProjectPartCommandLine(projectPart);
-    FilePath filePath{Utils::PathString(jointedFilePath)};
-
-    BuildDependencyCollector collector(m_filePathCache);
-
-    collector.setExcludedFilePaths(generateProjectPartSourcePaths(projectPart));
+    clang::tooling::ClangTool tool = m_clangTool.createOutputTool();
 
-    collector.addFile(filePath, projectPart.sourcePathIds, arguments);
+    auto action = std::make_unique<GeneratePCHActionFactory>();
 
-    collector.addUnsavedFiles(m_unsavedFiles);
-
-    collector.collect();
-
-    jointFile->remove();
-
-    return collector.includeIds();
+    return tool.run(action.get()) != 1;
 }
 
-Utils::SmallString PchCreator::generateProjectPathPchHeaderFilePath(
-        const V2::ProjectPartContainer &projectPart) const
+FilePath PchCreator::generatePchHeaderFilePath() const
 {
-    return Utils::SmallString{generateProjectPartPchFilePathWithoutExtension(projectPart), ".h"};
-}
+    std::uniform_int_distribution<std::mt19937_64::result_type> distribution;
 
-Utils::SmallString PchCreator::generateProjectPartPchFilePath(
-        const V2::ProjectPartContainer &projectPart) const
-{
-    return Utils::SmallString{generateProjectPartPchFilePathWithoutExtension(projectPart), ".pch"};
+    return FilePathView{Utils::PathString{Utils::SmallString(m_environment.pchBuildDirectory()),
+                                          "/",
+                                          std::to_string(distribution(randomNumberGenator)),
+                                          ".h"}};
 }
 
-Utils::SmallString PchCreator::generateProjectPartSourceFilePath(const V2::ProjectPartContainer &projectPart) const
+FilePath PchCreator::generatePchFilePath() const
 {
-    return Utils::SmallString{generateProjectPartPchFilePathWithoutExtension(projectPart), ".cpp"};
-}
+    std::uniform_int_distribution<std::uint_fast64_t> distribution(
+        1, std::numeric_limits<std::uint_fast64_t>::max());
 
-Utils::SmallStringVector PchCreator::generateProjectPartPchCompilerArguments(
-        const V2::ProjectPartContainer &projectPart) const
-{
-    Utils::SmallStringVector arguments;
-    arguments.reserve(5);
-
-    arguments.emplace_back("-x");
-    arguments.emplace_back("c++-header");
-    arguments.emplace_back("-Xclang");
-    arguments.emplace_back("-emit-pch");
-    arguments.emplace_back("-o");
-    arguments.emplace_back(generateProjectPartPchFilePath(projectPart));
-    arguments.emplace_back(generateProjectPathPchHeaderFilePath(projectPart));
-
-    return arguments;
+    return FilePathView{Utils::PathString{Utils::SmallString(m_environment.pchBuildDirectory()),
+                                          "/",
+                                          std::to_string(distribution(randomNumberGenator)),
+                                          ".pch"}};
 }
 
-Utils::SmallStringVector PchCreator::generateProjectPartClangCompilerArguments(
-        const V2::ProjectPartContainer &projectPart) const
+std::vector<std::string> PchCreator::generateClangCompilerArguments(
+    PchTask &&pchTask,
+    FilePathView sourceFilePath,
+    FilePathView pchOutputPath)
 {
-    Utils::SmallStringVector compilerArguments = projectPart.arguments.clone();
-    const auto pchArguments = generateProjectPartPchCompilerArguments(projectPart);
-
-    append(compilerArguments, pchArguments);
+    CommandLineBuilder<PchTask> builder{pchTask,
+                                        pchTask.toolChainArguments,
+                                        sourceFilePath,
+                                        pchOutputPath,
+                                        pchTask.systemPchPath};
 
-    return compilerArguments;
+    return builder.commandLine;
 }
 
-IdPaths PchCreator::generateProjectPartPch(const V2::ProjectPartContainer &projectPart)
+void PchCreator::generatePch(PchTask &&pchTask)
 {
     long long lastModified = QDateTime::currentSecsSinceEpoch();
-    auto includes = generateProjectPartPchIncludes(projectPart);
-    auto content = generatePchIncludeFileContent(topIncludeIds(includes));
-    auto pchIncludeFilePath = generateProjectPathPchHeaderFilePath(projectPart);
-    auto pchFilePath = generateProjectPartPchFilePath(projectPart);
-    generateFileWithContent(pchIncludeFilePath, content);
+    auto content = generatePchIncludeFileContent(pchTask.includes);
+    auto pchSourceFilePath = generatePchHeaderFilePath();
+    auto pchOutputPath = generatePchFilePath();
+    generateFileWithContent(pchSourceFilePath, content);
 
-    bool success = generatePch(generateProjectPartClangCompilerArguments(projectPart));
+    m_clangTool.addFile(
+        pchSourceFilePath.directory(),
+        pchSourceFilePath.name(),
+        "",
+        generateClangCompilerArguments(std::move(pchTask), pchSourceFilePath, pchOutputPath));
 
-    m_projectPartPch.projectPartId = projectPart.projectPartId;
+    bool success = generatePch();
+
+    m_projectPartPch.projectPartId = pchTask.projectPartId();
 
     if (success) {
-        m_projectPartPch.pchPath = std::move(pchFilePath);
+        m_projectPartPch.pchPath = std::move(pchOutputPath);
         m_projectPartPch.lastModified = lastModified;
     }
-
-    return {projectPart.projectPartId.clone(), allIncludeIds(includes)};
-}
-
-void PchCreator::generatePchDeprecated(const V2::ProjectPartContainer &projectPart)
-{
-    m_projectIncludeIds = generateProjectPartPch(projectPart);
-}
-
-void PchCreator::generatePch(const PchTask &pchTask)
-{
-
-}
-
-IdPaths PchCreator::takeProjectIncludes()
-{
-    return std::move(m_projectIncludeIds);
 }
 
 const ProjectPartPch &PchCreator::projectPartPch()
@@ -363,19 +163,12 @@ bool PchCreator::isUsed() const
 
 void PchCreator::clear()
 {
-    m_projectPartPch = ProjectPartPch{};
-    m_projectIncludeIds = IdPaths{};
+    m_projectPartPch = {};
 }
 
 void PchCreator::doInMainThreadAfterFinished()
 {
     m_pchManagerClient.precompiledHeadersUpdated(ProjectPartPchs{m_projectPartPch});
-    m_fileSystemWatcher.updateIdPaths({takeProjectIncludes()});
-}
-
-const IdPaths &PchCreator::projectIncludes() const
-{
-    return m_projectIncludeIds;
 }
 
 const FilePathCaching &PchCreator::filePathCache()
@@ -383,9 +176,8 @@ const FilePathCaching &PchCreator::filePathCache()
     return m_filePathCache;
 }
 
-std::unique_ptr<QFile> PchCreator::generateFileWithContent(
-        const Utils::SmallString &filePath,
-        const Utils::SmallString &content)
+std::unique_ptr<QFile> PchCreator::generateFileWithContent(const Utils::SmallString &filePath,
+                                                           const Utils::SmallString &content)
 {
     std::unique_ptr<QFile> precompiledIncludeFile(new QFile(QString(filePath)));
 
@@ -397,41 +189,4 @@ std::unique_ptr<QFile> PchCreator::generateFileWithContent(
     return precompiledIncludeFile;
 }
 
-FilePathIds PchCreator::topIncludeIds(const SourceEntries &includes)
-{
-    FilePathIds topIncludes;
-    topIncludes.reserve(includes.size());
-
-    for (SourceEntry include : includes) {
-        if (include.sourceType == SourceType::TopProjectInclude)
-            topIncludes.push_back(include.sourceId);
-    }
-
-    return topIncludes;
-}
-
-FilePathIds PchCreator::allIncludeIds(const SourceEntries &includes)
-{
-    FilePathIds allIncludes;
-    allIncludes.reserve(includes.size());
-
-    std::transform(includes.begin(),
-                   includes.end(),
-                   std::back_inserter(allIncludes),
-                   [](auto &&entry) { return entry.sourceId; });
-
-    return allIncludes;
-}
-
-QByteArray PchCreator::projectPartHash(const V2::ProjectPartContainer &projectPart)
-{
-    QCryptographicHash hash(QCryptographicHash::Sha1);
-
-    hashProjectPart(hash, projectPart);
-
-    auto result = hash.result();
-
-    return result.toBase64(QByteArray::Base64UrlEncoding | QByteArray::OmitTrailingEquals);
-}
-
 } // namespace ClangBackEnd
diff --git a/src/tools/clangpchmanagerbackend/source/pchcreator.h b/src/tools/clangpchmanagerbackend/source/pchcreator.h
index 34170e2bb5..ce1b7ab1eb 100644
--- a/src/tools/clangpchmanagerbackend/source/pchcreator.h
+++ b/src/tools/clangpchmanagerbackend/source/pchcreator.h
@@ -29,12 +29,14 @@
 
 #include "idpaths.h"
 #include "sourceentry.h"
+#include "clangtool.h"
 
 #include <filepathcaching.h>
 #include <projectpartpch.h>
-#include <projectpartcontainerv2.h>
+#include <projectpartcontainer.h>
 
 #include <vector>
+#include <random>
 
 QT_FORWARD_DECLARE_CLASS(QFile)
 QT_FORWARD_DECLARE_CLASS(QCryptographicHash)
@@ -60,18 +62,13 @@ class PchCreator final : public PchCreatorInterface
 public:
     PchCreator(Environment &environment,
                Sqlite::Database &database,
-               PchManagerClientInterface &pchManagerClient,
-               ClangPathWatcherInterface &fileSystemWatcher)
-        : m_filePathCache(database),
-          m_environment(environment),
-          m_pchManagerClient(pchManagerClient),
-          m_fileSystemWatcher(fileSystemWatcher)
-    {
-    }
-
-    void generatePchDeprecated(const V2::ProjectPartContainer &projectsPart) override;
-    void generatePch(const PchTask &pchTask) override;
-    IdPaths takeProjectIncludes() override;
+               PchManagerClientInterface &pchManagerClient)
+        : m_filePathCache(database)
+        , m_environment(environment)
+        , m_pchManagerClient(pchManagerClient)
+    {}
+
+    void generatePch(PchTask &&pchTask) override;
     const ProjectPartPch &projectPartPch() override;
     void setUnsavedFiles(const V2::FileContainers &fileContainers) override;
     void setIsUsed(bool isUsed) override;
@@ -79,56 +76,27 @@ public:
     void clear() override;
     void doInMainThreadAfterFinished() override;
 
-    const IdPaths &projectIncludes() const;
     const FilePathCaching &filePathCache();
 
     Utils::SmallString generatePchIncludeFileContent(const FilePathIds &includeIds) const;
-    bool generatePch(Utils::SmallStringVector &&commandLineArguments);
-
-    static QStringList convertToQStringList(const Utils::SmallStringVector &convertToQStringList);
-
-    Utils::SmallStringVector generateProjectPartCommandLine(
-            const V2::ProjectPartContainer &projectPart) const;
-    Utils::SmallString generateProjectPartPchFilePathWithoutExtension(
-            const V2::ProjectPartContainer &projectPart) const;
-    Utils::PathStringVector generateProjectPartHeaders(
-            const V2::ProjectPartContainer &projectPart) const;
-    Utils::SmallString generateProjectPartSourcesContent(
-            const V2::ProjectPartContainer &projectPart) const;
-    ClangBackEnd::FilePaths generateProjectPartSourcePaths(
-            const V2::ProjectPartContainer &projectPart) const;
-    SourceEntries generateProjectPartPchIncludes(
-            const V2::ProjectPartContainer &projectPart) const;
-    Utils::SmallString generateProjectPathPchHeaderFilePath(
-            const V2::ProjectPartContainer &projectPart) const;
-    Utils::SmallString  generateProjectPartPchFilePath(
-           const V2::ProjectPartContainer &projectPart) const;
-    Utils::SmallString  generateProjectPartSourceFilePath(
-           const V2::ProjectPartContainer &projectPart) const;
-    Utils::SmallStringVector generateProjectPartPchCompilerArguments(
-            const V2::ProjectPartContainer &projectPart) const;
-    Utils::SmallStringVector generateProjectPartClangCompilerArguments(
-             const V2::ProjectPartContainer &projectPart) const;
-    IdPaths generateProjectPartPch(
-            const V2::ProjectPartContainer &projectPart);
-    static std::unique_ptr<QFile> generateFileWithContent(
-            const Utils::SmallString &filePath,
-            const Utils::SmallString &content);
-
-    static FilePathIds topIncludeIds(const SourceEntries &includes);
-    static FilePathIds allIncludeIds(const SourceEntries &includes);
+    bool generatePch();
 
-private:
-    static QByteArray projectPartHash(const V2::ProjectPartContainer &projectPart);
+    FilePath generatePchHeaderFilePath() const;
+    FilePath generatePchFilePath() const;
+    static std::vector<std::string> generateClangCompilerArguments(PchTask &&pchTask,
+                                                                   FilePathView includePchHeaderPath,
+                                                                   FilePathView pchPath);
+    static std::unique_ptr<QFile> generateFileWithContent(const Utils::SmallString &filePath,
+                                                          const Utils::SmallString &content);
 
 private:
+    mutable std::mt19937_64 randomNumberGenator{std::random_device{}()};
+    ClangTool m_clangTool;
     ProjectPartPch m_projectPartPch;
-    IdPaths m_projectIncludeIds;
     FilePathCaching m_filePathCache;
     V2::FileContainers m_unsavedFiles;
     Environment &m_environment;
     PchManagerClientInterface &m_pchManagerClient;
-    ClangPathWatcherInterface &m_fileSystemWatcher;
     bool m_isUsed = false;
 };
 
diff --git a/src/tools/clangpchmanagerbackend/source/pchcreatorinterface.h b/src/tools/clangpchmanagerbackend/source/pchcreatorinterface.h
index caa2d67649..dd16e78f59 100644
--- a/src/tools/clangpchmanagerbackend/source/pchcreatorinterface.h
+++ b/src/tools/clangpchmanagerbackend/source/pchcreatorinterface.h
@@ -31,7 +31,7 @@
 #include "processorinterface.h"
 
 #include <filecontainerv2.h>
-#include <projectpartcontainerv2.h>
+#include <projectpartcontainer.h>
 
 namespace ClangBackEnd {
 
@@ -42,9 +42,7 @@ public:
     PchCreatorInterface(const PchCreatorInterface &) = delete;
     PchCreatorInterface &operator=(const PchCreatorInterface &) = delete;
 
-    virtual void generatePchDeprecated(const V2::ProjectPartContainer &projectsPart) = 0;
-    virtual void generatePch(const PchTask &pchTask) = 0;
-    virtual IdPaths takeProjectIncludes() = 0;
+    virtual void generatePch(PchTask &&pchTask) = 0;
     virtual const ProjectPartPch &projectPartPch() = 0;
 
 protected:
diff --git a/src/tools/clangpchmanagerbackend/source/pchmanagerserver.cpp b/src/tools/clangpchmanagerbackend/source/pchmanagerserver.cpp
index 0bc5c10879..2f53560632 100644
--- a/src/tools/clangpchmanagerbackend/source/pchmanagerserver.cpp
+++ b/src/tools/clangpchmanagerbackend/source/pchmanagerserver.cpp
@@ -28,7 +28,7 @@
 #include <pchmanagerclientinterface.h>
 #include <precompiledheadersupdatedmessage.h>
 #include <progressmessage.h>
-#include <projectpartqueue.h>
+#include <pchtaskgeneratorinterface.h>
 #include <removegeneratedfilesmessage.h>
 #include <removeprojectpartsmessage.h>
 #include <updategeneratedfilesmessage.h>
@@ -41,11 +41,11 @@
 namespace ClangBackEnd {
 
 PchManagerServer::PchManagerServer(ClangPathWatcherInterface &fileSystemWatcher,
-                                   ProjectPartQueueInterface &projectPartQueue,
+                                   PchTaskGeneratorInterface &pchTaskGenerator,
                                    ProjectPartsInterface &projectParts,
                                    GeneratedFilesInterface &generatedFiles)
     : m_fileSystemWatcher(fileSystemWatcher),
-      m_projectPartQueue(projectPartQueue),
+      m_pchTaskGenerator(pchTaskGenerator),
       m_projectParts(projectParts),
       m_generatedFiles(generatedFiles)
 {
@@ -55,12 +55,14 @@ PchManagerServer::PchManagerServer(ClangPathWatcherInterface &fileSystemWatcher,
 void PchManagerServer::end()
 {
     QCoreApplication::exit();
-
 }
 
 void PchManagerServer::updateProjectParts(UpdateProjectPartsMessage &&message)
 {
-    m_projectPartQueue.addProjectParts(m_projectParts.update(message.takeProjectsParts()));
+    m_toolChainsArgumentsCache.update(message.projectsParts, message.toolChainArguments);
+
+    m_pchTaskGenerator.addProjectParts(
+        m_projectParts.update(message.takeProjectsParts()), std::move(message.toolChainArguments));
 }
 
 void PchManagerServer::removeProjectParts(RemoveProjectPartsMessage &&message)
@@ -69,7 +71,9 @@ void PchManagerServer::removeProjectParts(RemoveProjectPartsMessage &&message)
 
     m_projectParts.remove(message.projectsPartIds);
 
-    m_projectPartQueue.removeProjectParts(message.projectsPartIds);
+    m_pchTaskGenerator.removeProjectParts(message.projectsPartIds);
+
+    m_toolChainsArgumentsCache.remove(message.projectsPartIds);
 }
 
 void PchManagerServer::updateGeneratedFiles(UpdateGeneratedFilesMessage &&message)
@@ -84,7 +88,12 @@ void PchManagerServer::removeGeneratedFiles(RemoveGeneratedFilesMessage &&messag
 
 void PchManagerServer::pathsWithIdsChanged(const Utils::SmallStringVector &ids)
 {
-    m_projectPartQueue.addProjectParts(m_projectParts.projects(ids));
+    ArgumentsEntries entries = m_toolChainsArgumentsCache.arguments(ids);
+
+    for (ArgumentsEntry &entry : entries) {
+        m_pchTaskGenerator.addProjectParts(
+            m_projectParts.projects(entry.ids), std::move(entry.arguments));
+    }
 }
 
 void PchManagerServer::pathsChanged(const FilePathIds &/*filePathIds*/)
diff --git a/src/tools/clangpchmanagerbackend/source/pchmanagerserver.h b/src/tools/clangpchmanagerbackend/source/pchmanagerserver.h
index b3ff135f52..0c4bd0cc66 100644
--- a/src/tools/clangpchmanagerbackend/source/pchmanagerserver.h
+++ b/src/tools/clangpchmanagerbackend/source/pchmanagerserver.h
@@ -30,6 +30,7 @@
 #include "pchcreatorinterface.h"
 #include "pchmanagerserverinterface.h"
 #include "projectpartsinterface.h"
+#include "toolchainargumentscache.h"
 
 #include <generatedfilesinterface.h>
 #include <ipcclientprovider.h>
@@ -37,7 +38,7 @@
 namespace ClangBackEnd {
 
 class SourceRangesAndDiagnosticsForQueryMessage;
-class ProjectPartQueueInterface;
+class PchTaskGeneratorInterface;
 
 class PchManagerServer : public PchManagerServerInterface,
                          public ClangPathWatcherNotifier,
@@ -46,7 +47,7 @@ class PchManagerServer : public PchManagerServerInterface,
 {
 public:
     PchManagerServer(ClangPathWatcherInterface &fileSystemWatcher,
-                     ProjectPartQueueInterface &projectPartQueue,
+                     PchTaskGeneratorInterface &pchTaskGenerator,
                      ProjectPartsInterface &projectParts,
                      GeneratedFilesInterface &generatedFiles);
 
@@ -63,9 +64,10 @@ public:
 
 private:
     ClangPathWatcherInterface &m_fileSystemWatcher;
-    ProjectPartQueueInterface &m_projectPartQueue;
+    PchTaskGeneratorInterface &m_pchTaskGenerator;
     ProjectPartsInterface &m_projectParts;
     GeneratedFilesInterface &m_generatedFiles;
+    ToolChainsArgumentsCache m_toolChainsArgumentsCache;
 };
 
 } // namespace ClangBackEnd
diff --git a/src/tools/clangpchmanagerbackend/source/pchtask.h b/src/tools/clangpchmanagerbackend/source/pchtask.h
index a78b199215..071cbfcb6b 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtask.h
+++ b/src/tools/clangpchmanagerbackend/source/pchtask.h
@@ -28,8 +28,11 @@
 #include "builddependency.h"
 
 #include <compilermacro.h>
+#include <filepath.h>
+#include <includesearchpath.h>
 
 #include <utils/smallstringvector.h>
+#include <utils/cpplanguage_details.h>
 
 namespace ClangBackEnd {
 
@@ -39,21 +42,45 @@ public:
     PchTask(Utils::SmallString &&projectPartId,
             FilePathIds &&includes,
             CompilerMacros &&compilerMacros,
-            UsedMacros &&usedMacros)
+            UsedMacros &&usedMacros,
+            Utils::SmallStringVector toolChainArguments,
+            IncludeSearchPaths systemIncludeSearchPaths,
+            IncludeSearchPaths projectIncludeSearchPaths,
+            Utils::Language language = Utils::Language::Cxx,
+            Utils::LanguageVersion languageVersion = Utils::LanguageVersion::CXX98,
+            Utils::LanguageExtension languageExtension = Utils::LanguageExtension::None)
         : projectPartIds({projectPartId})
         , includes(includes)
         , compilerMacros(compilerMacros)
         , usedMacros(usedMacros)
+        , systemIncludeSearchPaths(std::move(systemIncludeSearchPaths))
+        , projectIncludeSearchPaths(std::move(projectIncludeSearchPaths))
+        , toolChainArguments(std::move(toolChainArguments))
+        , language(language)
+        , languageVersion(languageVersion)
+        , languageExtension(languageExtension)
     {}
 
     PchTask(Utils::SmallStringVector &&projectPartIds,
             FilePathIds &&includes,
             CompilerMacros &&compilerMacros,
-            UsedMacros &&usedMacros)
+            UsedMacros &&usedMacros,
+            Utils::SmallStringVector toolChainArguments,
+            IncludeSearchPaths systemIncludeSearchPaths,
+            IncludeSearchPaths projectIncludeSearchPaths,
+            Utils::Language language = Utils::Language::Cxx,
+            Utils::LanguageVersion languageVersion = Utils::LanguageVersion::CXX98,
+            Utils::LanguageExtension languageExtension = Utils::LanguageExtension::None)
         : projectPartIds(std::move(projectPartIds))
         , includes(includes)
         , compilerMacros(compilerMacros)
         , usedMacros(usedMacros)
+        , systemIncludeSearchPaths(std::move(systemIncludeSearchPaths))
+        , projectIncludeSearchPaths(std::move(projectIncludeSearchPaths))
+        , toolChainArguments(std::move(toolChainArguments))
+        , language(language)
+        , languageVersion(languageVersion)
+        , languageExtension(languageExtension)
     {}
 
     friend bool operator==(const PchTask &first, const PchTask &second)
@@ -61,17 +88,29 @@ public:
         return first.systemPchPath == second.systemPchPath
                && first.projectPartIds == second.projectPartIds && first.includes == second.includes
                && first.compilerMacros == second.compilerMacros
-               && first.usedMacros == second.usedMacros;
+               && first.usedMacros == second.usedMacros
+               && first.systemIncludeSearchPaths == second.systemIncludeSearchPaths
+               && first.projectIncludeSearchPaths == second.projectIncludeSearchPaths
+               && first.toolChainArguments == second.toolChainArguments
+               && first.language == second.language
+               && first.languageVersion == second.languageVersion
+               && first.languageExtension == second.languageExtension;
     }
 
     Utils::SmallStringView projectPartId() const { return projectPartIds.front(); }
 
 public:
-    Utils::PathString systemPchPath;
+    FilePath systemPchPath;
     Utils::SmallStringVector projectPartIds;
     FilePathIds includes;
     CompilerMacros compilerMacros;
     UsedMacros usedMacros;
+    IncludeSearchPaths systemIncludeSearchPaths;
+    IncludeSearchPaths projectIncludeSearchPaths;
+    Utils::SmallStringVector toolChainArguments;
+    Utils::Language language = Utils::Language::Cxx;
+    Utils::LanguageVersion languageVersion = Utils::LanguageVersion::CXX98;
+    Utils::LanguageExtension languageExtension = Utils::LanguageExtension::None;
 };
 
 class PchTaskSet
diff --git a/src/tools/clangpchmanagerbackend/source/pchtaskgenerator.cpp b/src/tools/clangpchmanagerbackend/source/pchtaskgenerator.cpp
index 37311aa238..8159dbeb12 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtaskgenerator.cpp
+++ b/src/tools/clangpchmanagerbackend/source/pchtaskgenerator.cpp
@@ -34,7 +34,8 @@
 
 namespace ClangBackEnd {
 
-void PchTaskGenerator::create(V2::ProjectPartContainers &&projectParts)
+void PchTaskGenerator::addProjectParts(ProjectPartContainers &&projectParts,
+                                       Utils::SmallStringVector &&toolChainArguments)
 {
     PchTaskSets pchTaskSets;
     pchTaskSets.reserve(projectParts.size());
@@ -46,18 +47,33 @@ void PchTaskGenerator::create(V2::ProjectPartContainers &&projectParts)
         filter.filter(projectPart.compilerMacros);
 
         pchTaskSets.emplace_back(PchTask{projectPart.projectPartId.clone(),
-                                         std::move(filter.systemIncludes),
+                                         std::move(filter.topSystemIncludes),
                                          std::move(filter.systemCompilerMacros),
-                                         std::move(filter.systemUsedMacros)
-
-                                 },
+                                         std::move(filter.systemUsedMacros),
+                                         projectPart.toolChainArguments,
+                                         projectPart.systemIncludeSearchPaths,
+                                         projectPart.projectIncludeSearchPaths,
+                                         projectPart.language,
+                                         projectPart.languageVersion,
+                                         projectPart.languageExtension},
                                  PchTask{std::move(projectPart.projectPartId),
-                                         std::move(filter.projectIncludes),
+                                         std::move(filter.topProjectIncludes),
                                          std::move(filter.projectCompilerMacros),
-                                         std::move(filter.projectUsedMacros)});
+                                         std::move(filter.projectUsedMacros),
+                                         projectPart.toolChainArguments,
+                                         projectPart.systemIncludeSearchPaths,
+                                         projectPart.projectIncludeSearchPaths,
+                                         projectPart.language,
+                                         projectPart.languageVersion,
+                                         projectPart.languageExtension});
     }
 
-    m_pchTasksMergerInterface.mergeTasks(std::move(pchTaskSets));
+    m_pchTasksMergerInterface.mergeTasks(std::move(pchTaskSets), std::move(toolChainArguments));
+}
+
+void PchTaskGenerator::removeProjectParts(const Utils::SmallStringVector &projectsPartIds)
+{
+    m_pchTasksMergerInterface.removePchTasks(projectsPartIds);
 }
 
 } // namespace ClangBackEnd
diff --git a/src/tools/clangpchmanagerbackend/source/pchtaskgenerator.h b/src/tools/clangpchmanagerbackend/source/pchtaskgenerator.h
index d7a7937d80..b5669b7b3f 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtaskgenerator.h
+++ b/src/tools/clangpchmanagerbackend/source/pchtaskgenerator.h
@@ -26,8 +26,9 @@
 #pragma once
 
 #include "pchtask.h"
+#include "pchtaskgeneratorinterface.h"
 
-#include <projectpartcontainerv2.h>
+#include <projectpartcontainer.h>
 
 namespace ClangBackEnd {
 
@@ -35,7 +36,7 @@ class PchTasksMergerInterface;
 
 class BuildDependenciesProviderInterface;
 
-class PchTaskGenerator
+class PchTaskGenerator : public PchTaskGeneratorInterface
 {
 public:
     PchTaskGenerator(BuildDependenciesProviderInterface &buildDependenciesProvider,
@@ -44,7 +45,9 @@ public:
         , m_pchTasksMergerInterface(pchTasksMergerInterface)
     {}
 
-    void create(V2::ProjectPartContainers &&projectParts);
+    void addProjectParts(ProjectPartContainers &&projectParts,
+                         Utils::SmallStringVector &&toolChainArguments);
+    void removeProjectParts(const Utils::SmallStringVector &projectsPartIds);
 
 private:
     BuildDependenciesProviderInterface &m_buildDependenciesProvider;
diff --git a/src/tools/clangpchmanagerbackend/source/projectpartqueueinterface.h b/src/tools/clangpchmanagerbackend/source/pchtaskgeneratorinterface.h
index 0b705fe312..4546284265 100644
--- a/src/tools/clangpchmanagerbackend/source/projectpartqueueinterface.h
+++ b/src/tools/clangpchmanagerbackend/source/pchtaskgeneratorinterface.h
@@ -25,19 +25,20 @@
 
 #pragma once
 
-#include "queueinterface.h"
-
-#include <projectpartcontainerv2.h>
+#include <projectpartcontainer.h>
 
 namespace ClangBackEnd {
 
-class ProjectPartQueueInterface : public QueueInterface
+class PchTaskGeneratorInterface
 {
 public:
-    virtual void addProjectParts(V2::ProjectPartContainers &&projectParts) = 0;
+    virtual void addProjectParts(ProjectPartContainers &&projectParts,
+                                 Utils::SmallStringVector &&toolChainArguments)
+        = 0;
     virtual void removeProjectParts(const Utils::SmallStringVector &projectsPartIds) = 0;
 
 protected:
-    ~ProjectPartQueueInterface() = default;
+    ~PchTaskGeneratorInterface() = default;
 };
+
 } // namespace ClangBackEnd
diff --git a/src/tools/clangpchmanagerbackend/source/pchtaskqueue.cpp b/src/tools/clangpchmanagerbackend/source/pchtaskqueue.cpp
index 6b82290ef1..6c1a09fd3e 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtaskqueue.cpp
+++ b/src/tools/clangpchmanagerbackend/source/pchtaskqueue.cpp
@@ -52,8 +52,6 @@ void PchTaskQueue::addPchTasks(PchTasks &&newPchTasks, PchTasks &destination)
     destination = std::move(mergedPchTasks);
 
     m_progressCounter.addTotal(int(destination.size() - oldSize));
-
-    processEntries();
 }
 
 void PchTaskQueue::removePchTasksByProjectPartId(const Utils::SmallStringVector &projectsPartIds,
@@ -143,22 +141,17 @@ std::vector<PchTaskQueue::Task> PchTaskQueue::createProjectTasks(PchTasks &&pchT
 
     auto convert = [this](auto &&pchTask) {
         return [pchTask = std::move(pchTask), this](PchCreatorInterface &pchCreator) mutable {
-            Sqlite::DeferredTransaction readTransaction(m_transactionsInterface);
+            const auto projectPartId = pchTask.projectPartId();
             pchTask.systemPchPath = m_precompiledHeaderStorage.fetchSystemPrecompiledHeaderPath(
-                pchTask.projectPartId());
-            readTransaction.commit();
-            pchCreator.generatePch(pchTask);
+                projectPartId);
+            pchCreator.generatePch(std::move(pchTask));
             const auto &projectPartPch = pchCreator.projectPartPch();
-            Sqlite::ImmediateTransaction writeTransaction(m_transactionsInterface);
             if (projectPartPch.pchPath.empty()) {
-                m_precompiledHeaderStorage.deleteProjectPrecompiledHeader(pchTask.projectPartId());
+                m_precompiledHeaderStorage.deleteProjectPrecompiledHeader(projectPartId);
             } else {
-                m_precompiledHeaderStorage
-                    .insertProjectPrecompiledHeader(pchTask.projectPartId(),
-                                                    projectPartPch.pchPath,
-                                                    projectPartPch.lastModified);
+                m_precompiledHeaderStorage.insertProjectPrecompiledHeader(
+                    projectPartId, projectPartPch.pchPath, projectPartPch.lastModified);
             }
-            writeTransaction.commit();
         };
     };
 
@@ -176,21 +169,17 @@ std::vector<PchTaskQueue::Task> PchTaskQueue::createSystemTasks(PchTasks &&pchTa
     tasks.reserve(pchTasks.size());
 
     auto convert = [this](auto &&pchTask) {
-        return [pchTask = std::move(pchTask), this](PchCreatorInterface &pchCreator) {
-            pchCreator.generatePch(pchTask);
+        return [pchTask = std::move(pchTask), this](PchCreatorInterface &pchCreator) mutable {
+            const auto projectPartIds = pchTask.projectPartIds;
+            pchCreator.generatePch(std::move(pchTask));
             const auto &projectPartPch = pchCreator.projectPartPch();
-            Sqlite::ImmediateTransaction transaction(m_transactionsInterface);
-            for (Utils::SmallStringView projectPartId : pchTask.projectPartIds) {
-                if (projectPartPch.pchPath.empty()) {
-                    m_precompiledHeaderStorage.deleteSystemPrecompiledHeader(projectPartId);
-                } else {
-                    m_precompiledHeaderStorage
-                        .insertSystemPrecompiledHeader(projectPartId,
-                                                       projectPartPch.pchPath,
-                                                       projectPartPch.lastModified);
-                }
+            if (projectPartPch.pchPath.empty()) {
+                m_precompiledHeaderStorage.deleteSystemPrecompiledHeaders(projectPartIds);
+            } else {
+                m_precompiledHeaderStorage.insertSystemPrecompiledHeaders(projectPartIds,
+                                                                          projectPartPch.pchPath,
+                                                                          projectPartPch.lastModified);
             }
-            transaction.commit();
         };
     };
 
diff --git a/src/tools/clangpchmanagerbackend/source/pchtasksmerger.cpp b/src/tools/clangpchmanagerbackend/source/pchtasksmerger.cpp
index a241c60764..9ace04e09d 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtasksmerger.cpp
+++ b/src/tools/clangpchmanagerbackend/source/pchtasksmerger.cpp
@@ -29,7 +29,8 @@
 
 namespace ClangBackEnd {
 
-void PchTasksMerger::mergeTasks(PchTaskSets &&taskSets)
+void PchTasksMerger::mergeTasks(PchTaskSets &&taskSets,
+                                Utils::SmallStringVector &&/*toolChainArguments*/)
 {
     PchTasks systemTasks;
     systemTasks.reserve(taskSets.size());
@@ -46,4 +47,9 @@ void PchTasksMerger::mergeTasks(PchTaskSets &&taskSets)
     m_pchTaskQueue.processEntries();
 }
 
+void PchTasksMerger::removePchTasks(const Utils::SmallStringVector &projectPartIds)
+{
+    m_pchTaskQueue.removePchTasks(projectPartIds);
+}
+
 } // namespace ClangBackEnd
diff --git a/src/tools/clangpchmanagerbackend/source/pchtasksmerger.h b/src/tools/clangpchmanagerbackend/source/pchtasksmerger.h
index 97bed64e99..9c777b8a7c 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtasksmerger.h
+++ b/src/tools/clangpchmanagerbackend/source/pchtasksmerger.h
@@ -39,7 +39,8 @@ public:
         : m_pchTaskQueue(pchTaskQueue)
     {}
 
-    void mergeTasks(PchTaskSets &&taskSets) override;
+    void mergeTasks(PchTaskSets &&taskSets, Utils::SmallStringVector &&toolChainArguments) override;
+    void removePchTasks(const Utils::SmallStringVector &projectPartIds) override;
 
 private:
     PchTaskQueueInterface &m_pchTaskQueue;
diff --git a/src/tools/clangpchmanagerbackend/source/pchtasksmergerinterface.h b/src/tools/clangpchmanagerbackend/source/pchtasksmergerinterface.h
index 4fe96581bc..a691766b49 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtasksmergerinterface.h
+++ b/src/tools/clangpchmanagerbackend/source/pchtasksmergerinterface.h
@@ -31,7 +31,8 @@ namespace ClangBackEnd {
 class PchTasksMergerInterface
 {
 public:
-    virtual void mergeTasks(PchTaskSets &&taskSets) = 0;
+    virtual void mergeTasks(PchTaskSets &&taskSets, Utils::SmallStringVector &&toolChainArguments) = 0;
+    virtual void removePchTasks(const Utils::SmallStringVector &projectPartIds) = 0;
 
 protected:
     ~PchTasksMergerInterface() = default;
diff --git a/src/tools/clangpchmanagerbackend/source/precompiledheaderstorage.h b/src/tools/clangpchmanagerbackend/source/precompiledheaderstorage.h
index 67ee9b4fe6..022f5d926b 100644
--- a/src/tools/clangpchmanagerbackend/source/precompiledheaderstorage.h
+++ b/src/tools/clangpchmanagerbackend/source/precompiledheaderstorage.h
@@ -48,8 +48,8 @@ public:
     }
 
     void insertProjectPrecompiledHeader(Utils::SmallStringView projectPartName,
-                                 Utils::SmallStringView pchPath,
-                                 long long pchBuildTime) override
+                                        Utils::SmallStringView pchPath,
+                                        long long pchBuildTime) override
     {
         try {
             Sqlite::ImmediateTransaction transaction{m_database};
@@ -76,42 +76,44 @@ public:
         }
     }
 
-    void insertSystemPrecompiledHeader(Utils::SmallStringView projectPartName,
-                                       Utils::SmallStringView pchPath,
-                                       long long pchBuildTime) override
+    void insertSystemPrecompiledHeaders(const Utils::SmallStringVector &projectPartNames,
+                                        Utils::SmallStringView pchPath,
+                                        long long pchBuildTime) override
     {
         try {
             Sqlite::ImmediateTransaction transaction{m_database};
 
-            m_insertProjectPartStatement.write(projectPartName);
-            m_insertSystemPrecompiledHeaderStatement.write(projectPartName, pchPath, pchBuildTime);
-
+            for (Utils::SmallStringView projectPartName : projectPartNames) {
+                m_insertProjectPartStatement.write(projectPartName);
+                m_insertSystemPrecompiledHeaderStatement.write(projectPartName, pchPath, pchBuildTime);
+            }
             transaction.commit();
         } catch (const Sqlite::StatementIsBusy) {
-            insertSystemPrecompiledHeader(projectPartName, pchPath, pchBuildTime);
+            insertSystemPrecompiledHeaders(projectPartNames, pchPath, pchBuildTime);
         }
     }
 
-    void deleteSystemPrecompiledHeader(Utils::SmallStringView projectPartName) override
+    void deleteSystemPrecompiledHeaders(const Utils::SmallStringVector &projectPartNames) override
     {
         try {
             Sqlite::ImmediateTransaction transaction{m_database};
 
-            m_deleteSystemPrecompiledHeaderStatement.write(projectPartName);
+            for (Utils::SmallStringView projectPartName : projectPartNames)
+                m_deleteSystemPrecompiledHeaderStatement.write(projectPartName);
 
             transaction.commit();
         } catch (const Sqlite::StatementIsBusy) {
-            deleteSystemPrecompiledHeader(projectPartName);
+            deleteSystemPrecompiledHeaders(projectPartNames);
         }
     }
 
-    Utils::PathString fetchSystemPrecompiledHeaderPath(Utils::SmallStringView projectPartName) override
+    FilePath fetchSystemPrecompiledHeaderPath(Utils::SmallStringView projectPartName) override
     {
         try {
             Sqlite::DeferredTransaction transaction{m_database};
 
-            auto value = m_fetchSystemPrecompiledHeaderPathStatement
-                             .template value<Utils::PathString>(projectPartName);
+            auto value = m_fetchSystemPrecompiledHeaderPathStatement.template value<FilePath>(
+                projectPartName);
 
             if (value)
                 return value.value();
@@ -121,7 +123,7 @@ public:
             return fetchSystemPrecompiledHeaderPath(projectPartName);
         }
 
-        return Utils::SmallStringView("");
+        return FilePath("");
     }
 
 public:
diff --git a/src/tools/clangpchmanagerbackend/source/precompiledheaderstorageinterface.h b/src/tools/clangpchmanagerbackend/source/precompiledheaderstorageinterface.h
index 2ade4e885a..2a7e11604b 100644
--- a/src/tools/clangpchmanagerbackend/source/precompiledheaderstorageinterface.h
+++ b/src/tools/clangpchmanagerbackend/source/precompiledheaderstorageinterface.h
@@ -25,7 +25,9 @@
 
 #pragma once
 
-#include <utils/smallstring.h>
+#include <filepath.h>
+
+#include <utils/smallstringvector.h>
 
 namespace ClangBackEnd {
 
@@ -42,13 +44,12 @@ public:
                                                 long long pchBuildTime)
         = 0;
     virtual void deleteProjectPrecompiledHeader(Utils::SmallStringView projectPartName) = 0;
-    virtual void insertSystemPrecompiledHeader(Utils::SmallStringView projectPartName,
-                                               Utils::SmallStringView pchPath,
-                                               long long pchBuildTime)
+    virtual void insertSystemPrecompiledHeaders(const Utils::SmallStringVector &projectPartNames,
+                                                Utils::SmallStringView pchPath,
+                                                long long pchBuildTime)
         = 0;
-    virtual void deleteSystemPrecompiledHeader(Utils::SmallStringView projectPartName) = 0;
-    virtual Utils::PathString fetchSystemPrecompiledHeaderPath(
-        Utils::SmallStringView projectPartName) = 0;
+    virtual void deleteSystemPrecompiledHeaders(const Utils::SmallStringVector &projectPartNames) = 0;
+    virtual FilePath fetchSystemPrecompiledHeaderPath(Utils::SmallStringView projectPartName) = 0;
 
 protected:
     ~PrecompiledHeaderStorageInterface() = default;
diff --git a/src/tools/clangpchmanagerbackend/source/projectpartqueue.cpp b/src/tools/clangpchmanagerbackend/source/projectpartqueue.cpp
deleted file mode 100644
index 48f133f7d7..0000000000
--- a/src/tools/clangpchmanagerbackend/source/projectpartqueue.cpp
+++ /dev/null
@@ -1,137 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2018 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of Qt Creator.
-**
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 3 as published by the Free Software
-** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-3.0.html.
-**
-****************************************************************************/
-
-#include "projectpartqueue.h"
-
-#include <pchcreatorinterface.h>
-#include <precompiledheaderstorageinterface.h>
-#include <progresscounter.h>
-#include <sqlitetransaction.h>
-
-namespace ClangBackEnd {
-
-void ProjectPartQueue::addProjectParts(V2::ProjectPartContainers &&projectParts)
-{
-    auto compare = [](const V2::ProjectPartContainer &first, const V2::ProjectPartContainer &second) {
-        return first.projectPartId < second.projectPartId;
-    };
-
-    const std::size_t oldSize = m_projectParts.size();
-
-    V2::ProjectPartContainers mergedProjectParts;
-    mergedProjectParts.reserve(m_projectParts.size() + projectParts.size());
-    std::set_union(std::make_move_iterator(projectParts.begin()),
-                   std::make_move_iterator(projectParts.end()),
-                   std::make_move_iterator(m_projectParts.begin()),
-                   std::make_move_iterator(m_projectParts.end()),
-                   std::back_inserter(mergedProjectParts),
-                   compare);
-
-    m_projectParts = std::move(mergedProjectParts);
-
-    m_progressCounter.addTotal(int(m_projectParts.size() - oldSize));
-
-    processEntries();
-}
-
-class CompareDifference
-{
-public:
-    bool operator()(const V2::ProjectPartContainer &first, const Utils::SmallString &second)
-    {
-        return first.projectPartId < second;
-    }
-
-    bool operator()(const Utils::SmallString &first, const V2::ProjectPartContainer &second)
-    {
-        return first < second.projectPartId;
-    }
-};
-
-void ProjectPartQueue::removeProjectParts(const Utils::SmallStringVector &projectsPartIds)
-{
-    const std::size_t oldSize = m_projectParts.size();
-
-    V2::ProjectPartContainers notToBeRemovedProjectParts;
-    notToBeRemovedProjectParts.reserve(m_projectParts.size());
-    std::set_difference(std::make_move_iterator(m_projectParts.begin()),
-                        std::make_move_iterator(m_projectParts.end()),
-                        projectsPartIds.begin(),
-                        projectsPartIds.end(),
-                        std::back_inserter(notToBeRemovedProjectParts),
-                        CompareDifference{});
-
-    m_projectParts = std::move(notToBeRemovedProjectParts);
-
-    m_progressCounter.removeTotal(int(oldSize - m_projectParts.size()));
-}
-
-void ProjectPartQueue::processEntries()
-{
-    uint taskCount = m_taskScheduler.slotUsage().free;
-
-    auto newEnd = std::prev(m_projectParts.end(), std::min<int>(int(taskCount), int(m_projectParts.size())));
-    m_taskScheduler.addTasks(
-                createPchTasks({std::make_move_iterator(newEnd),
-                                std::make_move_iterator(m_projectParts.end())}));
-    m_projectParts.erase(newEnd, m_projectParts.end());
-}
-
-const V2::ProjectPartContainers &ProjectPartQueue::projectParts() const
-{
-    return m_projectParts;
-}
-
-std::vector<ProjectPartQueue::Task> ProjectPartQueue::createPchTasks(
-        V2::ProjectPartContainers &&projectParts) const
-{
-    std::vector<Task> tasks;
-    tasks.reserve(projectParts.size());
-
-    auto convert = [this] (auto &&projectPart) {
-        return [projectPart=std::move(projectPart), this] (PchCreatorInterface &pchCreator) {
-            pchCreator.generatePchDeprecated(projectPart);
-            const auto &projectPartPch = pchCreator.projectPartPch();
-            Sqlite::ImmediateTransaction transaction(m_transactionsInterface);
-            if (projectPartPch.pchPath.empty()) {
-                m_precompiledHeaderStorage.deleteProjectPrecompiledHeader(projectPartPch.projectPartId);
-            } else {
-                m_precompiledHeaderStorage.insertProjectPrecompiledHeader(projectPartPch.projectPartId,
-                                                                   projectPartPch.pchPath,
-                                                                   projectPartPch.lastModified);
-            }
-            transaction.commit();
-        };
-    };
-
-    std::transform(std::make_move_iterator(projectParts.begin()),
-                   std::make_move_iterator(projectParts.end()),
-                   std::back_inserter(tasks),
-                   convert);
-
-    return tasks;
-}
-
-} // namespace ClangBackEnd
diff --git a/src/tools/clangpchmanagerbackend/source/projectpartqueue.h b/src/tools/clangpchmanagerbackend/source/projectpartqueue.h
deleted file mode 100644
index 9365d7e5cc..0000000000
--- a/src/tools/clangpchmanagerbackend/source/projectpartqueue.h
+++ /dev/null
@@ -1,74 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2018 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of Qt Creator.
-**
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 3 as published by the Free Software
-** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-3.0.html.
-**
-****************************************************************************/
-
-#pragma once
-
-#include "projectpartqueueinterface.h"
-#include "taskschedulerinterface.h"
-
-namespace Sqlite {
-class TransactionInterface;
-}
-
-namespace ClangBackEnd {
-
-class PrecompiledHeaderStorageInterface;
-class ProgressCounter;
-class PchTaskSchedulerInterface;
-class PchCreatorInterface;
-
-class ProjectPartQueue final : public ProjectPartQueueInterface
-{
-public:
-    using Task = std::function<void (PchCreatorInterface&)>;
-
-    ProjectPartQueue(TaskSchedulerInterface<Task> &taskScheduler,
-                     PrecompiledHeaderStorageInterface &precompiledHeaderStorage,
-                     Sqlite::TransactionInterface &transactionsInterface,
-                     ProgressCounter &progressCounter)
-        : m_taskScheduler(taskScheduler),
-          m_precompiledHeaderStorage(precompiledHeaderStorage),
-          m_transactionsInterface(transactionsInterface),
-          m_progressCounter(progressCounter)
-    {}
-
-    void addProjectParts(V2::ProjectPartContainers &&projectParts);
-    void removeProjectParts(const Utils::SmallStringVector &projectsPartIds);
-
-    void processEntries();
-
-    const V2::ProjectPartContainers &projectParts() const;
-
-    std::vector<Task> createPchTasks(V2::ProjectPartContainers &&projectParts) const;
-
-private:
-    V2::ProjectPartContainers m_projectParts;
-    TaskSchedulerInterface<Task> &m_taskScheduler;
-    PrecompiledHeaderStorageInterface &m_precompiledHeaderStorage;
-    Sqlite::TransactionInterface &m_transactionsInterface;
-    ProgressCounter &m_progressCounter;
-};
-
-} // namespace ClangBackEnd
diff --git a/src/tools/clangpchmanagerbackend/source/projectparts.cpp b/src/tools/clangpchmanagerbackend/source/projectparts.cpp
index 6be06380bf..bf2235fd13 100644
--- a/src/tools/clangpchmanagerbackend/source/projectparts.cpp
+++ b/src/tools/clangpchmanagerbackend/source/projectparts.cpp
@@ -25,7 +25,7 @@
 
 #include "projectparts.h"
 
-#include <projectpartcontainerv2.h>
+#include <projectpartcontainer.h>
 
 #include <algorithm>
 
@@ -33,7 +33,7 @@ namespace ClangBackEnd {
 
 inline namespace Pch {
 
-V2::ProjectPartContainers ProjectParts::update(V2::ProjectPartContainers &&projectsParts)
+ProjectPartContainers ProjectParts::update(ProjectPartContainers &&projectsParts)
 {
     auto updatedProjectPartContainers = newProjectParts(std::move(projectsParts));
 
@@ -44,7 +44,7 @@ V2::ProjectPartContainers ProjectParts::update(V2::ProjectPartContainers &&proje
 
 void ProjectParts::remove(const Utils::SmallStringVector &ids)
 {
-    auto shouldRemove = [&] (const V2::ProjectPartContainer &projectPart) {
+    auto shouldRemove = [&] (const ProjectPartContainer &projectPart) {
         return std::find(ids.begin(), ids.end(), projectPart.projectPartId) != ids.end();
     };
 
@@ -52,23 +52,23 @@ void ProjectParts::remove(const Utils::SmallStringVector &ids)
     m_projectParts.erase(newEnd, m_projectParts.end());
 }
 
-V2::ProjectPartContainers ProjectParts::projects(const Utils::SmallStringVector &projectPartIds) const
+ProjectPartContainers ProjectParts::projects(const Utils::SmallStringVector &projectPartIds) const
 {
-    V2::ProjectPartContainers projectPartsWithIds;
+    ProjectPartContainers projectPartsWithIds;
 
     std::copy_if(m_projectParts.begin(),
                  m_projectParts.end(),
                  std::back_inserter(projectPartsWithIds),
-                 [&] (const V2::ProjectPartContainer &projectPart) {
+                 [&] (const ProjectPartContainer &projectPart) {
         return std::binary_search(projectPartIds.begin(), projectPartIds.end(), projectPart.projectPartId);
     });
 
     return projectPartsWithIds;
 }
 
-V2::ProjectPartContainers ProjectParts::newProjectParts(V2::ProjectPartContainers &&projectsParts) const
+ProjectPartContainers ProjectParts::newProjectParts(ProjectPartContainers &&projectsParts) const
 {
-    V2::ProjectPartContainers updatedProjectPartContainers;
+    ProjectPartContainers updatedProjectPartContainers;
     updatedProjectPartContainers.reserve(projectsParts.size());
 
     std::set_difference(std::make_move_iterator(projectsParts.begin()),
@@ -80,12 +80,12 @@ V2::ProjectPartContainers ProjectParts::newProjectParts(V2::ProjectPartContainer
     return updatedProjectPartContainers;
 }
 
-void ProjectParts::mergeProjectParts(const V2::ProjectPartContainers &projectsParts)
+void ProjectParts::mergeProjectParts(const ProjectPartContainers &projectsParts)
 {
-    V2::ProjectPartContainers newProjectParts;
+    ProjectPartContainers newProjectParts;
     newProjectParts.reserve(m_projectParts.size() + projectsParts.size());
 
-    auto compare = [] (const V2::ProjectPartContainer &first, const V2::ProjectPartContainer &second) {
+    auto compare = [] (const ProjectPartContainer &first, const ProjectPartContainer &second) {
         return first.projectPartId < second.projectPartId;
     };
 
@@ -99,7 +99,7 @@ void ProjectParts::mergeProjectParts(const V2::ProjectPartContainers &projectsPa
     m_projectParts = newProjectParts;
 }
 
-const V2::ProjectPartContainers &ProjectParts::projectParts() const
+const ProjectPartContainers &ProjectParts::projectParts() const
 {
     return m_projectParts;
 }
diff --git a/src/tools/clangpchmanagerbackend/source/projectparts.h b/src/tools/clangpchmanagerbackend/source/projectparts.h
index c0d9c61e7f..dfe03fa037 100644
--- a/src/tools/clangpchmanagerbackend/source/projectparts.h
+++ b/src/tools/clangpchmanagerbackend/source/projectparts.h
@@ -38,17 +38,17 @@ inline namespace Pch {
 class ProjectParts final : public ProjectPartsInterface
 {
 public:
-    V2::ProjectPartContainers update(V2::ProjectPartContainers &&projectsParts) override;
+    ProjectPartContainers update(ProjectPartContainers &&projectsParts) override;
     void remove(const Utils::SmallStringVector &projectPartIds) override;
-    V2::ProjectPartContainers projects(const Utils::SmallStringVector &projectPartIds) const override;
+    ProjectPartContainers projects(const Utils::SmallStringVector &projectPartIds) const override;
 
 unittest_public:
-    V2::ProjectPartContainers newProjectParts(V2::ProjectPartContainers &&projectsParts) const;
-    void mergeProjectParts(const V2::ProjectPartContainers &projectsParts);
-    const V2::ProjectPartContainers &projectParts() const;
+    ProjectPartContainers newProjectParts(ProjectPartContainers &&projectsParts) const;
+    void mergeProjectParts(const ProjectPartContainers &projectsParts);
+    const ProjectPartContainers &projectParts() const;
 
 private:
-    V2::ProjectPartContainers m_projectParts;
+    ProjectPartContainers m_projectParts;
 };
 
 } // namespace Pch
diff --git a/src/tools/clangpchmanagerbackend/source/projectpartsinterface.h b/src/tools/clangpchmanagerbackend/source/projectpartsinterface.h
index 97d6c5bfc2..f84ad98090 100644
--- a/src/tools/clangpchmanagerbackend/source/projectpartsinterface.h
+++ b/src/tools/clangpchmanagerbackend/source/projectpartsinterface.h
@@ -25,7 +25,7 @@
 
 #pragma once
 
-#include <projectpartcontainerv2.h>
+#include <projectpartcontainer.h>
 
 namespace ClangBackEnd {
 
@@ -36,9 +36,9 @@ public:
     ProjectPartsInterface(const ProjectPartsInterface &) = delete;
     ProjectPartsInterface &operator=(const ProjectPartsInterface &) = delete;
 
-    virtual V2::ProjectPartContainers update(V2::ProjectPartContainers &&projectsParts) = 0;
+    virtual ProjectPartContainers update(ProjectPartContainers &&projectsParts) = 0;
     virtual void remove(const Utils::SmallStringVector &projectPartIds) = 0;
-    virtual V2::ProjectPartContainers projects(const Utils::SmallStringVector &projectPartIds) const = 0;
+    virtual ProjectPartContainers projects(const Utils::SmallStringVector &projectPartIds) const = 0;
 
 protected:
     ~ProjectPartsInterface() = default;
diff --git a/src/tools/clangpchmanagerbackend/source/sourceentry.h b/src/tools/clangpchmanagerbackend/source/sourceentry.h
index 3cc0fb455a..e903baf3f6 100644
--- a/src/tools/clangpchmanagerbackend/source/sourceentry.h
+++ b/src/tools/clangpchmanagerbackend/source/sourceentry.h
@@ -56,41 +56,81 @@ public:
     int64 value = -1;
 };
 
-class SourceEntry
+class SourceTimeStamp
 {
+protected:
     using int64 = long long;
 public:
+    SourceTimeStamp(int sourceId, int64 lastModified)
+        : lastModified(lastModified)
+        , sourceId(sourceId)
+    {}
+
+    SourceTimeStamp(FilePathId sourceId, TimeStamp lastModified)
+        : lastModified(lastModified)
+        , sourceId(sourceId)
+    {}
+
+    friend bool operator<(SourceTimeStamp first, SourceTimeStamp second)
+    {
+        return first.sourceId < second.sourceId;
+    }
+
+    friend bool operator<(SourceTimeStamp first, FilePathId second)
+    {
+        return first.sourceId < second;
+    }
+
+    friend bool operator<(FilePathId first, SourceTimeStamp second)
+    {
+        return first < second.sourceId;
+    }
+
+    friend bool operator==(SourceTimeStamp first, SourceTimeStamp second)
+    {
+        return first.sourceId == second.sourceId && first.lastModified == second.lastModified;
+    }
+
+    friend bool operator!=(SourceTimeStamp first, SourceTimeStamp second)
+    {
+        return !(first == second);
+    }
+
+public:
+    TimeStamp lastModified;
+    FilePathId sourceId;
+};
+
+using SourceTimeStamps = std::vector<SourceTimeStamp>;
+
+class SourceEntry : public SourceTimeStamp
+{
+
+public:
     SourceEntry(int sourceId, int64 lastModified, int sourceType)
-        : lastModified(lastModified),
-          sourceId(sourceId),
-          sourceType(static_cast<SourceType>(sourceType))
+        : SourceTimeStamp(sourceId, lastModified)
+        , sourceType(static_cast<SourceType>(sourceType))
     {}
 
     SourceEntry(FilePathId sourceId, SourceType sourceType, TimeStamp lastModified)
-        : lastModified(lastModified),
-          sourceId(sourceId),
-          sourceType(sourceType)
+        : SourceTimeStamp(sourceId, lastModified)
+        , sourceType(sourceType)
     {}
 
-    friend
-    bool operator<(SourceEntry first, SourceEntry second)
+    friend bool operator<(SourceEntry first, SourceEntry second)
     {
         return first.sourceId < second.sourceId;
     }
 
-    friend
-    bool operator==(SourceEntry first, SourceEntry second)
+    friend bool operator==(SourceEntry first, SourceEntry second)
     {
-        return first.sourceId == second.sourceId
-            && first.sourceType == second.sourceType
-            && first.lastModified == second.lastModified ;
+        return first.sourceId == second.sourceId && first.sourceType == second.sourceType
+               && first.lastModified == second.lastModified;
     }
 
     friend bool operator!=(SourceEntry first, SourceEntry second) { return !(first == second); }
 
 public:
-    TimeStamp lastModified;
-    FilePathId sourceId;
     SourceType sourceType = SourceType::UserInclude;
 };
 
diff --git a/src/tools/clangpchmanagerbackend/source/taskscheduler.h b/src/tools/clangpchmanagerbackend/source/taskscheduler.h
index e2891a1163..621baef090 100644
--- a/src/tools/clangpchmanagerbackend/source/taskscheduler.h
+++ b/src/tools/clangpchmanagerbackend/source/taskscheduler.h
@@ -56,6 +56,8 @@ class ProcessorManagerInterface;
 class QueueInterface;
 class SymbolStorageInterface;
 
+enum class CallDoInMainThreadAfterFinished : char { Yes, No };
+
 template <typename ProcessorManager,
           typename Task>
 class TaskScheduler : public TaskSchedulerInterface<Task>
@@ -68,23 +70,22 @@ public:
                   QueueInterface &queue,
                   ProgressCounter &progressCounter,
                   uint hardwareConcurrency,
+                  CallDoInMainThreadAfterFinished callDoInMainThreadAfterFinished,
                   std::launch launchPolicy = std::launch::async)
-        : m_processorManager(processorManager),
-          m_queue(queue),
-          m_progressCounter(progressCounter),
-          m_hardwareConcurrency(hardwareConcurrency),
-          m_launchPolicy(launchPolicy)
+        : m_processorManager(processorManager)
+        , m_queue(queue)
+        , m_progressCounter(progressCounter)
+        , m_hardwareConcurrency(hardwareConcurrency)
+        , m_launchPolicy(launchPolicy)
+        , m_callDoInMainThreadAfterFinished(callDoInMainThreadAfterFinished)
     {}
 
     void addTasks(std::vector<Task> &&tasks)
     {
         for (auto &task : tasks) {
-            auto callWrapper = [&, task=std::move(task)] (auto processor)
-                    -> ProcessorInterface& {
+            auto callWrapper = [&, task = std::move(task)](auto processor) -> ProcessorInterface & {
                 task(processor.get());
-                executeInLoop([&] {
-                    m_queue.processEntries();
-                });
+                executeInLoop([&] { m_queue.processEntries(); });
 
                 return processor;
             };
@@ -130,9 +131,10 @@ private:
 
         auto split = std::partition(m_futures.begin(), m_futures.end(), notReady);
 
-        std::for_each(split, m_futures.end(), [] (Future &future) {
+        std::for_each(split, m_futures.end(), [&] (Future &future) {
             ProcessorInterface &processor = future.get();
-            processor.doInMainThreadAfterFinished();
+            if (m_callDoInMainThreadAfterFinished == CallDoInMainThreadAfterFinished::Yes)
+                processor.doInMainThreadAfterFinished();
             processor.setIsUsed(false);
             processor.clear();
         });
@@ -191,6 +193,7 @@ private:
     uint m_hardwareConcurrency;
     std::launch m_launchPolicy;
     bool m_isDisabled = false;
+    CallDoInMainThreadAfterFinished m_callDoInMainThreadAfterFinished;
 };
 
 } // namespace ClangBackEnd
diff --git a/src/tools/clangpchmanagerbackend/source/toolchainargumentscache.h b/src/tools/clangpchmanagerbackend/source/toolchainargumentscache.h
new file mode 100644
index 0000000000..4921b29a21
--- /dev/null
+++ b/src/tools/clangpchmanagerbackend/source/toolchainargumentscache.h
@@ -0,0 +1,187 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include <projectpartcontainer.h>
+
+#include <functional>
+
+namespace ClangBackEnd {
+
+struct ArgumentsEntry
+{
+    ArgumentsEntry(Utils::SmallStringVector &&ids, const Utils::SmallStringVector &arguments)
+        : ids(std::move(ids))
+        , arguments(arguments)
+    {}
+
+    ArgumentsEntry(const Utils::SmallStringVector &ids, const Utils::SmallStringVector &arguments)
+        : ids(ids)
+        , arguments(arguments)
+    {}
+
+    void mergeIds(Utils::SmallStringVector &&newIds)
+    {
+        Utils::SmallStringVector mergedIds;
+        mergedIds.reserve(ids.size() + newIds.size());
+
+        std::set_union(std::make_move_iterator(ids.begin()),
+                       std::make_move_iterator(ids.end()),
+                       std::make_move_iterator(newIds.begin()),
+                       std::make_move_iterator(newIds.end()),
+                       std::back_inserter(mergedIds));
+
+        ids = mergedIds;
+    }
+
+    void removeIds(const Utils::SmallStringVector &idsToBeRemoved)
+    {
+        Utils::SmallStringVector idsWithout;
+        idsWithout.reserve(ids.size());
+        std::set_difference(std::make_move_iterator(ids.begin()),
+                            std::make_move_iterator(ids.end()),
+                            idsToBeRemoved.begin(),
+                            idsToBeRemoved.end(),
+                            std::back_inserter(idsWithout));
+
+        ids = idsWithout;
+    }
+
+    Utils::SmallStringVector ids;
+    Utils::SmallStringVector arguments;
+};
+
+using ArgumentsEntries = std::vector<ArgumentsEntry>;
+
+class ToolChainsArgumentsCache
+{
+public:
+    void update(const ProjectPartContainers &projectParts,
+                const Utils::SmallStringVector &arguments)
+    {
+        struct Compare
+        {
+            bool operator()(const ArgumentsEntry &entry, const Utils::SmallStringVector &arguments)
+            {
+                return entry.arguments < arguments;
+            }
+
+            bool operator()(const Utils::SmallStringVector &arguments, const ArgumentsEntry &entry)
+            {
+                return arguments < entry.arguments;
+            }
+        };
+
+        auto found = std::lower_bound(m_argumentEntries.begin(),
+                                      m_argumentEntries.end(),
+                                      arguments,
+                                      Compare{});
+
+        if (found != m_argumentEntries.end() && found->arguments == arguments) {
+            auto ids = createIds(projectParts);
+            auto removeIds = [&] (ArgumentsEntry &entry) {
+                entry.removeIds(ids);
+            };
+            std::for_each(m_argumentEntries.begin(), found, removeIds);
+            std::for_each(std::next(found), m_argumentEntries.end(), removeIds);
+            found->mergeIds(std::move(ids));
+        } else {
+            auto ids = createIds(projectParts);
+            for (ArgumentsEntry &entry : m_argumentEntries)
+                entry.removeIds(ids);
+            found = m_argumentEntries.emplace(found, std::move(ids), arguments);
+        }
+
+        removeEmptyEntries();
+    }
+
+    void remove(const Utils::SmallStringVector &idsToBeRemoved)
+    {
+        ArgumentsEntries entries;
+        for (ArgumentsEntry &entry : m_argumentEntries) {
+            Utils::SmallStringVector usedIds;
+            std::set_difference(entry.ids.begin(),
+                                entry.ids.end(),
+                                idsToBeRemoved.begin(),
+                                idsToBeRemoved.end(),
+                                std::back_inserter(usedIds));
+
+            entry.ids = std::move(usedIds);
+        }
+
+        removeEmptyEntries();
+    }
+
+    ArgumentsEntries arguments(const Utils::SmallStringVector &ids) const
+    {
+        ArgumentsEntries entries;
+        for (const ArgumentsEntry &entry : m_argumentEntries) {
+            Utils::SmallStringVector usedIds;
+            std::set_intersection(entry.ids.begin(),
+                                  entry.ids.end(),
+                                  ids.begin(),
+                                  ids.end(),
+                                  std::back_inserter(usedIds));
+
+            if (!usedIds.empty())
+                entries.emplace_back(usedIds, entry.arguments);
+        }
+
+        return entries;
+    }
+
+    std::size_t size() const
+    {
+        return m_argumentEntries.size();
+    }
+
+private:
+    static Utils::SmallStringVector createIds(const ProjectPartContainers &projectParts)
+    {
+        Utils::SmallStringVector ids;
+        ids.reserve(projectParts.size());
+        for (const auto &projectPart : projectParts)
+            ids.emplace_back(projectPart.projectPartId);
+
+        std::sort(ids.begin(), ids.end());
+
+        return ids;
+    }
+
+    void removeEmptyEntries()
+    {
+        auto newEnd = std::remove_if(m_argumentEntries.begin(),
+                                     m_argumentEntries.end(),
+                                     [](const auto &entry) { return entry.ids.empty(); });
+
+        m_argumentEntries.erase(newEnd, m_argumentEntries.end());
+    }
+
+private:
+    std::vector<ArgumentsEntry> m_argumentEntries;
+};
+
+}
diff --git a/src/tools/clangpchmanagerbackend/source/usedmacrofilter.h b/src/tools/clangpchmanagerbackend/source/usedmacrofilter.h
index 459eab6282..05e6a8eaf6 100644
--- a/src/tools/clangpchmanagerbackend/source/usedmacrofilter.h
+++ b/src/tools/clangpchmanagerbackend/source/usedmacrofilter.h
@@ -52,6 +52,8 @@ public:
     {
         systemIncludes.reserve(includes.size());
         projectIncludes.reserve(includes.size());
+        topSystemIncludes.reserve(includes.size() / 10);
+        topProjectIncludes.reserve(includes.size() / 10);
 
         for (SourceEntry include : includes)
             filterInclude(include);
@@ -76,10 +78,16 @@ private:
     {
         switch (include.sourceType) {
         case SourceType::TopSystemInclude:
+            topSystemIncludes.emplace_back(include.sourceId);
+            systemIncludes.emplace_back(include.sourceId);
+            break;
         case SourceType::SystemInclude:
             systemIncludes.emplace_back(include.sourceId);
             break;
         case SourceType::TopProjectInclude:
+            topProjectIncludes.emplace_back(include.sourceId);
+            projectIncludes.emplace_back(include.sourceId);
+            break;
         case SourceType::ProjectInclude:
             projectIncludes.emplace_back(include.sourceId);
             break;
@@ -173,6 +181,8 @@ private:
 public:
     FilePathIds projectIncludes;
     FilePathIds systemIncludes;
+    FilePathIds topProjectIncludes;
+    FilePathIds topSystemIncludes;
     UsedMacros projectUsedMacros;
     UsedMacros systemUsedMacros;
     CompilerMacros projectCompilerMacros;
diff --git a/src/tools/clangrefactoringbackend/source/clangtool.cpp b/src/tools/clangrefactoringbackend/source/clangtool.cpp
index e2df298c8d..dea6e1190a 100644
--- a/src/tools/clangrefactoringbackend/source/clangtool.cpp
+++ b/src/tools/clangrefactoringbackend/source/clangtool.cpp
@@ -50,9 +50,9 @@ void ClangTool::addFile(std::string &&directory,
                         std::vector<std::string> &&commandLine)
 {
     m_fileContents.emplace_back(toNativePath(std::move(directory)),
-                              std::move(fileName),
-                              std::move(content),
-                              std::move(commandLine));
+                                std::move(fileName),
+                                std::move(content),
+                                std::move(commandLine));
 
     const auto &fileContent = m_fileContents.back();
 
@@ -140,4 +140,13 @@ clang::tooling::ClangTool ClangTool::createTool() const
     return tool;
 }
 
+clang::tooling::ClangTool ClangTool::createOutputTool() const
+{
+    clang::tooling::ClangTool tool = createTool();
+
+    tool.clearArgumentsAdjusters();
+
+    return tool;
+}
+
 } // namespace ClangBackEnd
diff --git a/src/tools/clangrefactoringbackend/source/clangtool.h b/src/tools/clangrefactoringbackend/source/clangtool.h
index 9f0676a397..deee71599b 100644
--- a/src/tools/clangrefactoringbackend/source/clangtool.h
+++ b/src/tools/clangrefactoringbackend/source/clangtool.h
@@ -91,6 +91,7 @@ public:
     void addUnsavedFiles(const V2::FileContainers &unsavedFiles);
 
     clang::tooling::ClangTool createTool() const;
+    clang::tooling::ClangTool createOutputTool() const;
 
 private:
     RefactoringCompilationDatabase m_compilationDatabase;
diff --git a/src/tools/clangrefactoringbackend/source/projectpartartefact.cpp b/src/tools/clangrefactoringbackend/source/projectpartartefact.cpp
index 13856e1411..1c62bec8fe 100644
--- a/src/tools/clangrefactoringbackend/source/projectpartartefact.cpp
+++ b/src/tools/clangrefactoringbackend/source/projectpartartefact.cpp
@@ -33,16 +33,7 @@
 
 namespace ClangBackEnd {
 
-ProjectPartArtefact::ProjectPartArtefact(Utils::SmallStringView compilerArgumentsText,
-                                         Utils::SmallStringView compilerMacrosText,
-                                         Utils::SmallStringView includeSearchPaths,
-                                         int projectPartId)
-    : compilerArguments(toStringVector(compilerArgumentsText)),
-      compilerMacros(toCompilerMacros(compilerMacrosText)),
-      includeSearchPaths(toStringVector(includeSearchPaths)),
-      projectPartId(projectPartId)
-{
-}
+
 
 Utils::SmallStringVector ProjectPartArtefact::toStringVector(Utils::SmallStringView jsonText)
 {
@@ -58,19 +49,35 @@ Utils::SmallStringVector ProjectPartArtefact::toStringVector(Utils::SmallStringV
 
 CompilerMacros ProjectPartArtefact::createCompilerMacrosFromDocument(const QJsonDocument &document)
 {
-    QJsonObject object = document.object();
+    QJsonArray array = document.array();
     CompilerMacros macros;
-    macros.reserve(object.size());
+    macros.reserve(array.size());
 
-    int index = 0;
-    for (auto current = object.constBegin(); current != object.constEnd(); ++current)
-        macros.emplace_back(current.key(), current.value().toString(), ++index);
+    for (const QJsonValueRef entry : array) {
+        const QJsonArray entryArray = entry.toArray();
+        macros.emplace_back(
+            entryArray[0].toString(), entryArray[1].toString(), entryArray[2].toInt());
+    }
 
     std::sort(macros.begin(), macros.end());
 
     return macros;
 }
 
+IncludeSearchPaths ProjectPartArtefact::createIncludeSearchPathsFromDocument(const QJsonDocument &document)
+{
+    QJsonArray array = document.array();
+    IncludeSearchPaths paths;
+    paths.reserve(array.size());
+
+    for (const QJsonValueRef entry : array) {
+        const QJsonArray entryArray = entry.toArray();
+        paths.emplace_back(entryArray[0].toString(), entryArray[1].toInt(), entryArray[2].toInt());
+    }
+
+    return paths;
+}
+
 CompilerMacros ProjectPartArtefact::toCompilerMacros(Utils::SmallStringView jsonText)
 {
     if (jsonText.isEmpty())
@@ -93,6 +100,17 @@ QJsonDocument ProjectPartArtefact::createJsonDocument(Utils::SmallStringView jso
     return document;
 }
 
+IncludeSearchPaths ProjectPartArtefact::toIncludeSearchPaths(Utils::SmallStringView jsonText)
+{
+
+    if (jsonText.isEmpty())
+        return {};
+
+    QJsonDocument document = createJsonDocument(jsonText, "Include search paths parsing error");
+
+    return createIncludeSearchPathsFromDocument(document);
+}
+
 void ProjectPartArtefact::checkError(const char *whatError, const QJsonParseError &error)
 {
     if (error.error != QJsonParseError::NoError) {
@@ -104,7 +122,9 @@ void ProjectPartArtefact::checkError(const char *whatError, const QJsonParseErro
 bool operator==(const ProjectPartArtefact &first, const ProjectPartArtefact &second)
 {
     return first.compilerArguments == second.compilerArguments
-            && first.compilerMacros == second.compilerMacros;
+           && first.compilerMacros == second.compilerMacros
+           && first.systemIncludeSearchPaths == second.systemIncludeSearchPaths
+           && first.projectIncludeSearchPaths == second.projectIncludeSearchPaths;
 }
 
 } // namespace ClangBackEnd
diff --git a/src/tools/clangrefactoringbackend/source/projectpartartefact.h b/src/tools/clangrefactoringbackend/source/projectpartartefact.h
index ee508abe27..44ca9acadb 100644
--- a/src/tools/clangrefactoringbackend/source/projectpartartefact.h
+++ b/src/tools/clangrefactoringbackend/source/projectpartartefact.h
@@ -30,6 +30,7 @@
 #include <utils/smallstringvector.h>
 
 #include <compilermacro.h>
+#include <includesearchpath.h>
 
 QT_FORWARD_DECLARE_CLASS(QJsonDocument)
 QT_FORWARD_DECLARE_STRUCT(QJsonParseError)
@@ -41,27 +42,30 @@ class ProjectPartArtefact
 public:
     ProjectPartArtefact(Utils::SmallStringView compilerArgumentsText,
                         Utils::SmallStringView compilerMacrosText,
-                        Utils::SmallStringView includeSearchPaths,
-                        int projectPartId);
+                        Utils::SmallStringView systemIncludeSearchPathsText,
+                        Utils::SmallStringView projectIncludeSearchPathsText,
+                        int projectPartId)
+        : compilerArguments(toStringVector(compilerArgumentsText))
+        , compilerMacros(toCompilerMacros(compilerMacrosText))
+        , systemIncludeSearchPaths(toIncludeSearchPaths(systemIncludeSearchPathsText))
+        , projectIncludeSearchPaths(toIncludeSearchPaths(projectIncludeSearchPathsText))
+        , projectPartId(projectPartId)
+    {}
 
-    static
-    Utils::SmallStringVector toStringVector(Utils::SmallStringView jsonText);
-    static
-    CompilerMacros createCompilerMacrosFromDocument(const QJsonDocument &document);
-    static
-    CompilerMacros toCompilerMacros(Utils::SmallStringView jsonText);
-    static
-    QJsonDocument createJsonDocument(Utils::SmallStringView jsonText,
-                                     const char *whatError);
-    static
-    void checkError(const char *whatError, const QJsonParseError &error);
-    friend
-    bool operator==(const ProjectPartArtefact &first, const ProjectPartArtefact &second);
+    static Utils::SmallStringVector toStringVector(Utils::SmallStringView jsonText);
+    static CompilerMacros createCompilerMacrosFromDocument(const QJsonDocument &document);
+    static IncludeSearchPaths createIncludeSearchPathsFromDocument(const QJsonDocument &document);
+    static CompilerMacros toCompilerMacros(Utils::SmallStringView jsonText);
+    static QJsonDocument createJsonDocument(Utils::SmallStringView jsonText, const char *whatError);
+    static IncludeSearchPaths toIncludeSearchPaths(Utils::SmallStringView jsonText);
+    static void checkError(const char *whatError, const QJsonParseError &error);
+    friend bool operator==(const ProjectPartArtefact &first, const ProjectPartArtefact &second);
 
 public:
     Utils::SmallStringVector compilerArguments;
     CompilerMacros compilerMacros;
-    Utils::SmallStringVector includeSearchPaths;
+    IncludeSearchPaths systemIncludeSearchPaths;
+    IncludeSearchPaths projectIncludeSearchPaths;
     int projectPartId = -1;
 };
 
diff --git a/src/tools/clangrefactoringbackend/source/symbolindexer.cpp b/src/tools/clangrefactoringbackend/source/symbolindexer.cpp
index 47a02e9fa3..0a45d361d9 100644
--- a/src/tools/clangrefactoringbackend/source/symbolindexer.cpp
+++ b/src/tools/clangrefactoringbackend/source/symbolindexer.cpp
@@ -25,8 +25,10 @@
 
 #include "symbolindexer.h"
 
-#include <symbolscollectorinterface.h>
-#include <symbolindexertaskqueue.h>
+#include "symbolscollectorinterface.h"
+#include "symbolindexertaskqueue.h"
+
+#include <commandlinebuilder.h>
 
 #include <chrono>
 #include <iostream>
@@ -65,7 +67,7 @@ SymbolIndexer::SymbolIndexer(SymbolIndexerTaskQueueInterface &symbolIndexerTaskQ
                              Sqlite::TransactionInterface &transactionInterface)
     : m_symbolIndexerTaskQueue(symbolIndexerTaskQueue),
       m_symbolStorage(symbolStorage),
-      m_usedMacroAndSourceStorage(usedMacroAndSourceStorage),
+      m_buildDependencyStorage(usedMacroAndSourceStorage),
       m_pathWatcher(pathWatcher),
       m_filePathCache(filePathCache),
       m_fileStatusCache(fileStatusCache),
@@ -74,20 +76,22 @@ SymbolIndexer::SymbolIndexer(SymbolIndexerTaskQueueInterface &symbolIndexerTaskQ
     pathWatcher.setNotifier(this);
 }
 
-void SymbolIndexer::updateProjectParts(V2::ProjectPartContainers &&projectParts)
+void SymbolIndexer::updateProjectParts(ProjectPartContainers &&projectParts)
 {
-        for (V2::ProjectPartContainer &projectPart : projectParts)
+        for (ProjectPartContainer &projectPart : projectParts)
             updateProjectPart(std::move(projectPart));
 }
 
-void SymbolIndexer::updateProjectPart(V2::ProjectPartContainer &&projectPart)
+void SymbolIndexer::updateProjectPart(ProjectPartContainer &&projectPart)
 {
     Sqlite::ImmediateTransaction transaction{m_transactionInterface};
     const auto optionalArtefact = m_symbolStorage.fetchProjectPartArtefact(projectPart.projectPartId);
-    int projectPartId = m_symbolStorage.insertOrUpdateProjectPart(projectPart.projectPartId,
-                                                                  projectPart.arguments,
-                                                                  projectPart.compilerMacros,
-                                                                  projectPart.includeSearchPaths);
+    int projectPartId = m_symbolStorage.insertOrUpdateProjectPart(
+        projectPart.projectPartId,
+        projectPart.toolChainArguments,
+        projectPart.compilerMacros,
+        projectPart.systemIncludeSearchPaths,
+        projectPart.projectIncludeSearchPaths);
     if (optionalArtefact)
         projectPartId = optionalArtefact->projectPartId;
     const Utils::optional<ProjectPartPch> optionalProjectPartPch = m_symbolStorage.fetchPrecompiledHeader(projectPartId);
@@ -97,14 +101,20 @@ void SymbolIndexer::updateProjectPart(V2::ProjectPartContainer &&projectPart)
     if (sourcePathIds.empty())
         return;
 
-    const Utils::SmallStringVector arguments = compilerArguments(projectPart.arguments,
-                                                                 optionalProjectPartPch);
+    using Builder = CommandLineBuilder<ProjectPartContainer, Utils::SmallStringVector>;
+    Builder commandLineBuilder{projectPart,
+                               projectPart.toolChainArguments,
+                               {},
+                               {},
+                               optionalProjectPartPch
+                                   ? FilePathView{optionalProjectPartPch.value().pchPath}
+                                   : FilePathView{}};
 
     std::vector<SymbolIndexerTask> symbolIndexerTask;
     symbolIndexerTask.reserve(projectPart.sourcePathIds.size());
     for (FilePathId sourcePathId : projectPart.sourcePathIds) {
-        auto indexing = [projectPartId, arguments, sourcePathId, this]
-                (SymbolsCollectorInterface &symbolsCollector) {
+        auto indexing = [projectPartId, arguments = commandLineBuilder.commandLine, sourcePathId, this](
+                            SymbolsCollectorInterface &symbolsCollector) {
             symbolsCollector.setFile(sourcePathId, arguments);
 
             symbolsCollector.collectSymbols();
@@ -114,14 +124,14 @@ void SymbolIndexer::updateProjectPart(V2::ProjectPartContainer &&projectPart)
             m_symbolStorage.addSymbolsAndSourceLocations(symbolsCollector.symbols(),
                                                          symbolsCollector.sourceLocations());
 
-            m_symbolStorage.updateProjectPartSources(projectPartId,
-                                                     symbolsCollector.sourceFiles());
+            m_symbolStorage.updateProjectPartSources(projectPartId, symbolsCollector.sourceFiles());
 
-            m_usedMacroAndSourceStorage.insertOrUpdateUsedMacros(symbolsCollector.usedMacros());
+            m_buildDependencyStorage.insertOrUpdateUsedMacros(symbolsCollector.usedMacros());
 
-            m_usedMacroAndSourceStorage.insertFileStatuses(symbolsCollector.fileStatuses());
+            m_buildDependencyStorage.insertFileStatuses(symbolsCollector.fileStatuses());
 
-            m_usedMacroAndSourceStorage.insertOrUpdateSourceDependencies(symbolsCollector.sourceDependencies());
+            m_buildDependencyStorage.insertOrUpdateSourceDependencies(
+                symbolsCollector.sourceDependencies());
 
             transaction.commit();
         };
@@ -155,22 +165,23 @@ void SymbolIndexer::updateChangedPath(FilePathId filePathId,
     m_fileStatusCache.update(filePathId);
 
     Sqlite::DeferredTransaction transaction{m_transactionInterface};
-    const Utils::optional<ProjectPartArtefact> optionalArtefact = m_symbolStorage.fetchProjectPartArtefact(filePathId);
+    const Utils::optional<ProjectPartArtefact> optionalArtefact = m_symbolStorage.fetchProjectPartArtefact(
+        filePathId);
     if (!optionalArtefact)
         return;
 
-    const Utils::optional<ProjectPartPch> optionalProjectPartPch = m_symbolStorage.fetchPrecompiledHeader(optionalArtefact->projectPartId);
+    const Utils::optional<ProjectPartPch> optionalProjectPartPch = m_symbolStorage.fetchPrecompiledHeader(
+        optionalArtefact->projectPartId);
     transaction.commit();
 
     if (!optionalArtefact.value().compilerArguments.empty()) {
-
         const ProjectPartArtefact &artefact = optionalArtefact.value();
 
         const Utils::SmallStringVector arguments = compilerArguments(artefact.compilerArguments,
                                                                      optionalProjectPartPch);
 
-        auto indexing = [projectPartId=artefact.projectPartId, arguments, filePathId, this]
-                (SymbolsCollectorInterface &symbolsCollector) {
+        auto indexing = [projectPartId = artefact.projectPartId, arguments, filePathId, this](
+                            SymbolsCollectorInterface &symbolsCollector) {
             symbolsCollector.setFile(filePathId, arguments);
 
             symbolsCollector.collectSymbols();
@@ -182,39 +193,43 @@ void SymbolIndexer::updateChangedPath(FilePathId filePathId,
 
             m_symbolStorage.updateProjectPartSources(projectPartId, symbolsCollector.sourceFiles());
 
-            m_usedMacroAndSourceStorage.insertOrUpdateUsedMacros(symbolsCollector.usedMacros());
+            m_buildDependencyStorage.insertOrUpdateUsedMacros(symbolsCollector.usedMacros());
 
-            m_usedMacroAndSourceStorage.insertFileStatuses(symbolsCollector.fileStatuses());
+            m_buildDependencyStorage.insertFileStatuses(symbolsCollector.fileStatuses());
 
-            m_usedMacroAndSourceStorage.insertOrUpdateSourceDependencies(symbolsCollector.sourceDependencies());
+            m_buildDependencyStorage.insertOrUpdateSourceDependencies(
+                symbolsCollector.sourceDependencies());
 
             transaction.commit();
         };
 
-        symbolIndexerTask.emplace_back(filePathId, optionalArtefact->projectPartId, std::move(indexing));
+        symbolIndexerTask.emplace_back(filePathId,
+                                       optionalArtefact->projectPartId,
+                                       std::move(indexing));
     }
 }
 
 bool SymbolIndexer::compilerMacrosOrIncludeSearchPathsAreDifferent(
-        const V2::ProjectPartContainer &projectPart,
+        const ProjectPartContainer &projectPart,
         const Utils::optional<ProjectPartArtefact> &optionalArtefact) const
 {
     if (optionalArtefact) {
         const ProjectPartArtefact &artefact = optionalArtefact.value();
         return projectPart.compilerMacros != artefact.compilerMacros
-             || projectPart.includeSearchPaths != artefact.includeSearchPaths;
+               || projectPart.systemIncludeSearchPaths != artefact.systemIncludeSearchPaths
+               || projectPart.projectIncludeSearchPaths != artefact.projectIncludeSearchPaths;
     }
 
     return true;
 }
 
-FilePathIds SymbolIndexer::filterChangedFiles(const V2::ProjectPartContainer &projectPart) const
+FilePathIds SymbolIndexer::filterChangedFiles(const ProjectPartContainer &projectPart) const
 {
     FilePathIds ids;
     ids.reserve(projectPart.sourcePathIds.size());
 
     for (const FilePathId &sourceId : projectPart.sourcePathIds) {
-        long long oldLastModified = m_usedMacroAndSourceStorage.fetchLowestLastModifiedTime(sourceId);
+        long long oldLastModified = m_buildDependencyStorage.fetchLowestLastModifiedTime(sourceId);
         long long currentLastModified =  m_fileStatusCache.lastModifiedTime(sourceId);
         if (oldLastModified < currentLastModified)
             ids.push_back(sourceId);
@@ -223,7 +238,7 @@ FilePathIds SymbolIndexer::filterChangedFiles(const V2::ProjectPartContainer &pr
     return ids;
 }
 
-FilePathIds SymbolIndexer::updatableFilePathIds(const V2::ProjectPartContainer &projectPart,
+FilePathIds SymbolIndexer::updatableFilePathIds(const ProjectPartContainer &projectPart,
                                                 const Utils::optional<ProjectPartArtefact> &optionalArtefact) const
 {
     if (compilerMacrosOrIncludeSearchPathsAreDifferent(projectPart, optionalArtefact))
@@ -233,8 +248,8 @@ FilePathIds SymbolIndexer::updatableFilePathIds(const V2::ProjectPartContainer &
 }
 
 Utils::SmallStringVector SymbolIndexer::compilerArguments(
-        Utils::SmallStringVector arguments,
-        const Utils::optional<ProjectPartPch> optionalProjectPartPch) const
+    Utils::SmallStringVector arguments,
+    const Utils::optional<ProjectPartPch> optionalProjectPartPch) const
 {
     if (optionalProjectPartPch) {
         arguments.emplace_back("-Xclang");
diff --git a/src/tools/clangrefactoringbackend/source/symbolindexer.h b/src/tools/clangrefactoringbackend/source/symbolindexer.h
index d9070005ce..55f62ffa5f 100644
--- a/src/tools/clangrefactoringbackend/source/symbolindexer.h
+++ b/src/tools/clangrefactoringbackend/source/symbolindexer.h
@@ -31,7 +31,7 @@
 #include "builddependenciesstorageinterface.h"
 #include "clangpathwatcher.h"
 
-#include <projectpartcontainerv2.h>
+#include <projectpartcontainer.h>
 #include <filecontainerv2.h>
 
 namespace ClangBackEnd {
@@ -49,8 +49,8 @@ public:
                   FileStatusCache &fileStatusCache,
                   Sqlite::TransactionInterface &transactionInterface);
 
-    void updateProjectParts(V2::ProjectPartContainers &&projectParts);
-    void updateProjectPart(V2::ProjectPartContainer &&projectPart);
+    void updateProjectParts(ProjectPartContainers &&projectParts);
+    void updateProjectPart(ProjectPartContainer &&projectPart);
 
     void pathsWithIdsChanged(const Utils::SmallStringVector &ids) override;
     void pathsChanged(const FilePathIds &filePathIds) override;
@@ -58,22 +58,23 @@ public:
                            std::vector<SymbolIndexerTask> &symbolIndexerTask);
 
     bool compilerMacrosOrIncludeSearchPathsAreDifferent(
-            const V2::ProjectPartContainer &projectPart,
+            const ProjectPartContainer &projectPart,
             const Utils::optional<ProjectPartArtefact> &optionalArtefact) const;
 
     FilePathIds filterChangedFiles(
-            const V2::ProjectPartContainer &projectPart) const;
+            const ProjectPartContainer &projectPart) const;
 
-    FilePathIds updatableFilePathIds(const V2::ProjectPartContainer &projectPart,
+    FilePathIds updatableFilePathIds(const ProjectPartContainer &projectPart,
                                      const Utils::optional<ProjectPartArtefact> &optionalArtefact) const;
 
-    Utils::SmallStringVector compilerArguments(Utils::SmallStringVector arguments,
-                                               const Utils::optional<ProjectPartPch> optionalProjectPartPch) const;
+    Utils::SmallStringVector compilerArguments(
+        Utils::SmallStringVector arguments,
+        const Utils::optional<ProjectPartPch> optionalProjectPartPch) const;
 
 private:
     SymbolIndexerTaskQueueInterface &m_symbolIndexerTaskQueue;
     SymbolStorageInterface &m_symbolStorage;
-    BuildDependenciesStorageInterface &m_usedMacroAndSourceStorage;
+    BuildDependenciesStorageInterface &m_buildDependencyStorage;
     ClangPathWatcherInterface &m_pathWatcher;
     FilePathCachingInterface &m_filePathCache;
     FileStatusCache &m_fileStatusCache;
diff --git a/src/tools/clangrefactoringbackend/source/symbolindexing.cpp b/src/tools/clangrefactoringbackend/source/symbolindexing.cpp
index 4f62b859f0..529396e9fa 100644
--- a/src/tools/clangrefactoringbackend/source/symbolindexing.cpp
+++ b/src/tools/clangrefactoringbackend/source/symbolindexing.cpp
@@ -27,7 +27,7 @@
 
 namespace ClangBackEnd {
 
-void SymbolIndexing::updateProjectParts(V2::ProjectPartContainers &&projectParts)
+void SymbolIndexing::updateProjectParts(ProjectPartContainers &&projectParts)
 {
     m_indexer.updateProjectParts(std::move(projectParts));
 }
diff --git a/src/tools/clangrefactoringbackend/source/symbolindexing.h b/src/tools/clangrefactoringbackend/source/symbolindexing.h
index 10e1be0358..6f52f863d8 100644
--- a/src/tools/clangrefactoringbackend/source/symbolindexing.h
+++ b/src/tools/clangrefactoringbackend/source/symbolindexing.h
@@ -81,12 +81,16 @@ public:
                    FilePathCachingInterface &filePathCache,
                    const GeneratedFiles &generatedFiles,
                    ProgressCounter::SetProgressCallback &&setProgressCallback)
-        : m_filePathCache(filePathCache),
-          m_usedMacroAndSourceStorage(database),
-          m_symbolStorage(database),
-          m_collectorManger(generatedFiles, database),
-          m_progressCounter(std::move(setProgressCallback)),
-          m_indexerScheduler(m_collectorManger, m_indexerQueue, m_progressCounter, std::thread::hardware_concurrency())
+        : m_filePathCache(filePathCache)
+        , m_buildDependencyStorage(database)
+        , m_symbolStorage(database)
+        , m_collectorManger(generatedFiles, database)
+        , m_progressCounter(std::move(setProgressCallback))
+        , m_indexerScheduler(m_collectorManger,
+                             m_indexerQueue,
+                             m_progressCounter,
+                             std::thread::hardware_concurrency(),
+                             CallDoInMainThreadAfterFinished::Yes)
     {
     }
 
@@ -109,12 +113,12 @@ public:
         }
     }
 
-    void updateProjectParts(V2::ProjectPartContainers &&projectParts) override;
+    void updateProjectParts(ProjectPartContainers &&projectParts) override;
 
 private:
     using SymbolIndexerTaskScheduler = TaskScheduler<SymbolsCollectorManager, SymbolIndexerTask::Callable>;
     FilePathCachingInterface &m_filePathCache;
-    BuildDependenciesStorage m_usedMacroAndSourceStorage;
+    BuildDependenciesStorage m_buildDependencyStorage;
     SymbolStorage m_symbolStorage;
     ClangPathWatcher<QFileSystemWatcher, QTimer> m_sourceWatcher{m_filePathCache};
     FileStatusCache m_fileStatusCache{m_filePathCache};
@@ -124,7 +128,7 @@ private:
     SymbolIndexerTaskQueue m_indexerQueue{m_indexerScheduler, m_progressCounter};
     SymbolIndexer m_indexer{m_indexerQueue,
                             m_symbolStorage,
-                            m_usedMacroAndSourceStorage,
+                            m_buildDependencyStorage,
                             m_sourceWatcher,
                             m_filePathCache,
                             m_fileStatusCache,
diff --git a/src/tools/clangrefactoringbackend/source/symbolindexinginterface.h b/src/tools/clangrefactoringbackend/source/symbolindexinginterface.h
index 70e16d7429..3feb9e1b9f 100644
--- a/src/tools/clangrefactoringbackend/source/symbolindexinginterface.h
+++ b/src/tools/clangrefactoringbackend/source/symbolindexinginterface.h
@@ -25,7 +25,7 @@
 
 #pragma once
 
-#include <projectpartcontainerv2.h>
+#include <projectpartcontainer.h>
 #include <filecontainerv2.h>
 
 namespace ClangBackEnd {
@@ -37,7 +37,7 @@ public:
     SymbolIndexingInterface(const SymbolIndexingInterface&) = delete;
     SymbolIndexingInterface &operator=(const SymbolIndexingInterface&) = delete;
 
-    virtual void updateProjectParts(V2::ProjectPartContainers &&projectParts) = 0;
+    virtual void updateProjectParts(ProjectPartContainers &&projectParts) = 0;
 
 protected:
     ~SymbolIndexingInterface() = default;
diff --git a/src/tools/clangrefactoringbackend/source/symbolstorage.h b/src/tools/clangrefactoringbackend/source/symbolstorage.h
index 02d52bfb50..0be04c04b6 100644
--- a/src/tools/clangrefactoringbackend/source/symbolstorage.h
+++ b/src/tools/clangrefactoringbackend/source/symbolstorage.h
@@ -31,6 +31,7 @@
 #include <sqliteexception.h>
 #include <sqlitetransaction.h>
 #include <sqlitetable.h>
+#include <includesearchpath.h>
 
 #include <QJsonArray>
 #include <QJsonDocument>
@@ -68,45 +69,39 @@ public:
     }
 
     int insertOrUpdateProjectPart(Utils::SmallStringView projectPartName,
-                                   const Utils::SmallStringVector &commandLineArguments,
-                                   const CompilerMacros &compilerMacros,
-                                   const Utils::SmallStringVector &includeSearchPaths) override
+                                  const Utils::SmallStringVector &commandLineArguments,
+                                  const CompilerMacros &compilerMacros,
+                                  const IncludeSearchPaths &systemIncludeSearchPaths,
+                                  const IncludeSearchPaths &projectIncludeSearchPaths) override
     {
-        m_database.setLastInsertedRowId(-1);
-
         Utils::SmallString compilerArguementsAsJson = toJson(commandLineArguments);
         Utils::SmallString compilerMacrosAsJson = toJson(compilerMacros);
-        Utils::SmallString includeSearchPathsAsJason = toJson(includeSearchPaths);
-
-        WriteStatement &insertStatement = m_insertProjectPartStatement;
-        insertStatement.write(projectPartName,
-                              compilerArguementsAsJson,
-                              compilerMacrosAsJson,
-                              includeSearchPathsAsJason);
-
-        if (m_database.lastInsertedRowId() == -1) {
-            WriteStatement &updateStatement = m_updateProjectPartStatement;
-            updateStatement.write(compilerArguementsAsJson,
-                                  compilerMacrosAsJson,
-                                  includeSearchPathsAsJason,
-                                  projectPartName);
-        }
+        Utils::SmallString systemIncludeSearchPathsAsJason = toJson(systemIncludeSearchPaths);
+        Utils::SmallString projectIncludeSearchPathsAsJason = toJson(projectIncludeSearchPaths);
+
+        m_insertOrUpdateProjectPartStatement.write(projectPartName,
+                                                   compilerArguementsAsJson,
+                                                   compilerMacrosAsJson,
+                                                   systemIncludeSearchPathsAsJason,
+                                                   projectIncludeSearchPathsAsJason);
+
+        auto projectPartId = m_getProjectPartIdStatement.template value<int>(projectPartName);
 
-        return int(m_database.lastInsertedRowId());
+        return projectPartId.value();
     }
 
     Utils::optional<ProjectPartArtefact> fetchProjectPartArtefact(FilePathId sourceId) const override
     {
         ReadStatement &statement = m_getProjectPartArtefactsBySourceId;
 
-        return statement.template value<ProjectPartArtefact, 4>(sourceId.filePathId);
+        return statement.template value<ProjectPartArtefact, 5>(sourceId.filePathId);
     }
 
     Utils::optional<ProjectPartArtefact> fetchProjectPartArtefact(Utils::SmallStringView projectPartName) const override
     {
         ReadStatement &statement = m_getProjectPartArtefactsByProjectPartName;
 
-        return statement.template value<ProjectPartArtefact, 4>(projectPartName);
+        return statement.template value<ProjectPartArtefact, 5>(projectPartName);
     }
 
     void updateProjectPartSources(int projectPartId,
@@ -137,12 +132,25 @@ public:
     static Utils::SmallString toJson(const CompilerMacros &compilerMacros)
     {
         QJsonDocument document;
-        QJsonObject object;
+        QJsonArray array;
 
         for (const CompilerMacro &macro : compilerMacros)
-            object.insert(QString(macro.key), QString(macro.value));
+            array.push_back(QJsonArray{{QString(macro.key), QString(macro.value), macro.index}});
 
-        document.setObject(object);
+        document.setArray(array);
+
+        return document.toJson(QJsonDocument::Compact);
+    }
+
+    static Utils::SmallString toJson(const IncludeSearchPaths &includeSearchPaths)
+    {
+        QJsonDocument document;
+        QJsonArray array;
+
+        for (const IncludeSearchPath &path : includeSearchPaths)
+            array.push_back(QJsonArray{{path.path.data(), path.index, int(path.type)}});
+
+        document.setArray(array);
 
         return document.toJson(QJsonDocument::Compact);
     }
@@ -299,14 +307,12 @@ public:
         "DELETE FROM newLocations",
         m_database
     };
-    WriteStatement m_insertProjectPartStatement{
-        "INSERT OR IGNORE INTO projectParts(projectPartName, compilerArguments, compilerMacros, includeSearchPaths) VALUES (?,?,?,?)",
-        m_database
-    };
-    WriteStatement m_updateProjectPartStatement{
-        "UPDATE projectParts SET compilerArguments = ?, compilerMacros = ?, includeSearchPaths = ? WHERE projectPartName = ?",
-        m_database
-    };
+    WriteStatement m_insertOrUpdateProjectPartStatement{
+        "INSERT INTO projectParts(projectPartName, compilerArguments, compilerMacros, "
+        "systemIncludeSearchPaths, projectIncludeSearchPaths) VALUES (?001,?002,?003,?004,?005) ON "
+        "CONFLICT(projectPartName) DO UPDATE SET compilerArguments=?002, compilerMacros=?003, "
+        "systemIncludeSearchPaths=?004, projectIncludeSearchPaths=?005",
+        m_database};
     mutable ReadStatement m_getProjectPartIdStatement{
         "SELECT projectPartId FROM projectParts WHERE projectPartName = ?",
         m_database
@@ -324,13 +330,14 @@ public:
         m_database
     };
     mutable ReadStatement m_getProjectPartArtefactsBySourceId{
-        "SELECT compilerArguments, compilerMacros, includeSearchPaths, projectPartId FROM projectParts WHERE projectPartId = (SELECT projectPartId FROM projectPartsSources WHERE sourceId = ?)",
-        m_database
-    };
+        "SELECT compilerArguments, compilerMacros, systemIncludeSearchPaths, projectIncludeSearchPaths, "
+        "projectPartId FROM projectParts WHERE projectPartId = (SELECT projectPartId FROM "
+        "projectPartsSources WHERE sourceId = ?)",
+        m_database};
     mutable ReadStatement m_getProjectPartArtefactsByProjectPartName{
-        "SELECT compilerArguments, compilerMacros, includeSearchPaths, projectPartId FROM projectParts WHERE projectPartName = ?",
-        m_database
-    };
+        "SELECT compilerArguments, compilerMacros, systemIncludeSearchPaths, "
+        "projectIncludeSearchPaths, projectPartId FROM projectParts WHERE projectPartName = ?",
+        m_database};
     mutable ReadStatement m_getPrecompiledHeader{
         "SELECT projectPchPath, projectPchBuildTime FROM precompiledHeaders WHERE projectPartId = ?",
         m_database
diff --git a/src/tools/clangrefactoringbackend/source/symbolstorageinterface.h b/src/tools/clangrefactoringbackend/source/symbolstorageinterface.h
index 0cb1dafd4f..3e51302c20 100644
--- a/src/tools/clangrefactoringbackend/source/symbolstorageinterface.h
+++ b/src/tools/clangrefactoringbackend/source/symbolstorageinterface.h
@@ -34,6 +34,8 @@
 #include "symbolentry.h"
 #include "usedmacro.h"
 
+#include <includesearchpath.h>
+
 #include <sqlitetransaction.h>
 
 #include <compilermacro.h>
@@ -48,15 +50,20 @@ public:
     SymbolStorageInterface &operator=(const SymbolStorageInterface &) = delete;
 
     virtual void addSymbolsAndSourceLocations(const SymbolEntries &symbolEntries,
-                                              const SourceLocationEntries &sourceLocations) = 0;
-    virtual int insertOrUpdateProjectPart(Utils::SmallStringView projectPartName,
-                                          const Utils::SmallStringVector &commandLineArguments,
-                                          const CompilerMacros &compilerMacros,
-                                          const Utils::SmallStringVector &includeSearchPaths) = 0;
-    virtual void updateProjectPartSources(int projectPartId,
-                                          const FilePathIds &sourceFilePathIds) = 0;
-    virtual Utils::optional<ProjectPartArtefact> fetchProjectPartArtefact(FilePathId sourceId) const = 0;
-    virtual Utils::optional<ProjectPartArtefact> fetchProjectPartArtefact(Utils::SmallStringView projectPartName) const = 0;
+                                              const SourceLocationEntries &sourceLocations)
+        = 0;
+    virtual int insertOrUpdateProjectPart(
+        Utils::SmallStringView projectPartName,
+        const Utils::SmallStringVector &commandLineArguments,
+        const CompilerMacros &compilerMacros,
+        const ClangBackEnd::IncludeSearchPaths &systemIncludeSearchPaths,
+        const ClangBackEnd::IncludeSearchPaths &projectIncludeSearchPaths)
+        = 0;
+    virtual void updateProjectPartSources(int projectPartId, const FilePathIds &sourceFilePathIds) = 0;
+    virtual Utils::optional<ProjectPartArtefact> fetchProjectPartArtefact(
+        FilePathId sourceId) const = 0;
+    virtual Utils::optional<ProjectPartArtefact> fetchProjectPartArtefact(
+        Utils::SmallStringView projectPartName) const = 0;
     virtual Utils::optional<ProjectPartPch> fetchPrecompiledHeader(int projectPartId) const = 0;
 
 protected:
diff --git a/tests/unit/unittest/builddependenciesprovider-test.cpp b/tests/unit/unittest/builddependenciesprovider-test.cpp
index cb39ec2bdf..2a5372c55d 100644
--- a/tests/unit/unittest/builddependenciesprovider-test.cpp
+++ b/tests/unit/unittest/builddependenciesprovider-test.cpp
@@ -63,18 +63,28 @@ protected:
                                                      mockModifiedTimeChecker,
                                                      mockBuildDependenciesGenerator,
                                                      mockSqliteTransactionBackend};
-    ClangBackEnd::V2::ProjectPartContainer projectPart1{"ProjectPart1",
-                                                        {"--yi"},
-                                                        {{"YI", "1", 1}},
-                                                        {"/yi"},
-                                                        {1},
-                                                        {2}};
-    ClangBackEnd::V2::ProjectPartContainer projectPart2{"ProjectPart2",
-                                                        {"--er"},
-                                                        {{"ER", "2", 1}},
-                                                        {"/er"},
-                                                        {1},
-                                                        {2, 3, 4}};
+    ClangBackEnd::ProjectPartContainer projectPart1{
+        "ProjectPart1",
+        {"--yi"},
+        {{"YI", "1", 1}},
+        {{"/includes", 1, ClangBackEnd::IncludeSearchPathType::BuiltIn}},
+        {{"/project/yi", 1, ClangBackEnd::IncludeSearchPathType::User}},
+        {1},
+        {2},
+        Utils::Language::C,
+        Utils::LanguageVersion::C11,
+        Utils::LanguageExtension::All};
+    ClangBackEnd::ProjectPartContainer projectPart2{
+        "ProjectPart2",
+        {"--er"},
+        {{"ER", "2", 1}},
+        {{"/includes", 1, ClangBackEnd::IncludeSearchPathType::BuiltIn}},
+        {{"/project/er", 1, ClangBackEnd::IncludeSearchPathType::User}},
+        {1},
+        {2, 3, 4},
+        Utils::Language::C,
+        Utils::LanguageVersion::C11,
+        Utils::LanguageExtension::All};
     SourceEntries firstSources{{1, SourceType::UserInclude, 1},
                                {2, SourceType::UserInclude, 1},
                                {10, SourceType::UserInclude, 1}};
diff --git a/tests/unit/unittest/builddependencycollector-test.cpp b/tests/unit/unittest/builddependencycollector-test.cpp
index 7a65361edb..1b42f143a0 100644
--- a/tests/unit/unittest/builddependencycollector-test.cpp
+++ b/tests/unit/unittest/builddependencycollector-test.cpp
@@ -529,25 +529,27 @@ TEST_F(BuildDependencyCollector, MissingInclude)
 
 TEST_F(BuildDependencyCollector, Create)
 {
+    using ClangBackEnd::IncludeSearchPathType;
     ClangBackEnd::BuildDependencyCollector collector{filePathCache};
-    ClangBackEnd::V2::ProjectPartContainer
-        projectPart{"project1",
-                    {"cc",
-                     "-I",
-                     TESTDATA_DIR "/builddependencycollector/external",
-                     "-I",
-                     TESTDATA_DIR "/builddependencycollector/project",
-                     "-isystem",
-                     TESTDATA_DIR "/builddependencycollector/system"},
-                    {},
-                    {},
-                    {
-                        id(TESTDATA_DIR "/builddependencycollector/project/header1.h"),
-                        id(TESTDATA_DIR "/builddependencycollector/project/header2.h"),
-                        id(TESTDATA_DIR "/builddependencycollector/project/missingfile.h"),
-                        id(TESTDATA_DIR "/builddependencycollector/project/macros.h"),
-                    },
-                    {id(TESTDATA_DIR "/builddependencycollector/project/main4.cpp")}};
+    ClangBackEnd::ProjectPartContainer projectPart{
+        "project1",
+        {},
+        {},
+        {{TESTDATA_DIR "/builddependencycollector/system", 1, IncludeSearchPathType::System}},
+        {
+            {TESTDATA_DIR "/builddependencycollector/project", 1, IncludeSearchPathType::User},
+            {TESTDATA_DIR "/builddependencycollector/external", 2, IncludeSearchPathType::User},
+        },
+        {
+            id(TESTDATA_DIR "/builddependencycollector/project/header1.h"),
+            id(TESTDATA_DIR "/builddependencycollector/project/header2.h"),
+            id(TESTDATA_DIR "/builddependencycollector/project/missingfile.h"),
+            id(TESTDATA_DIR "/builddependencycollector/project/macros.h"),
+        },
+        {id(TESTDATA_DIR "/builddependencycollector/project/main4.cpp")},
+        Utils::Language::Cxx,
+        Utils::LanguageVersion::CXX11,
+        Utils::LanguageExtension::None};
 
     auto buildDependency = collector.create(projectPart);
 
diff --git a/tests/unit/unittest/commandlinebuilder-test.cpp b/tests/unit/unittest/commandlinebuilder-test.cpp
new file mode 100644
index 0000000000..6cf673bf83
--- /dev/null
+++ b/tests/unit/unittest/commandlinebuilder-test.cpp
@@ -0,0 +1,481 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#include "googletest.h"
+
+#include <commandlinebuilder.h>
+#include <pchtask.h>
+#include <projectpartcontainer.h>
+
+namespace {
+template<typename ProjectInfo>
+using Builder = ClangBackEnd::CommandLineBuilder<ProjectInfo>;
+
+using ClangBackEnd::IncludeSearchPathType;
+
+template <typename ProjectInfo>
+class CommandLineBuilder : public testing::Test
+{
+};
+
+template <>
+class CommandLineBuilder<ClangBackEnd::PchTask> : public testing::Test
+{
+public:
+    CommandLineBuilder()
+    {
+        cppProjectInfo.language = Utils::Language::Cxx;
+    }
+
+public:
+    ClangBackEnd::PchTask emptyProjectInfo{"empty", {}, {}, {}, {}, {}, {}};
+    ClangBackEnd::PchTask cppProjectInfo{"project1", {}, {}, {}, {}, {}, {}};
+};
+
+template <>
+class CommandLineBuilder<ClangBackEnd::ProjectPartContainer> : public testing::Test
+{
+public:
+    CommandLineBuilder()
+    {
+        cppProjectInfo.language = Utils::Language::Cxx;
+    }
+
+public:
+    ClangBackEnd::ProjectPartContainer emptyProjectInfo{"empty",
+                                                        {},
+                                                        {},
+                                                        {},
+                                                        {},
+                                                        {},
+                                                        {},
+                                                        Utils::Language::Cxx,
+                                                        Utils::LanguageVersion::CXX98,
+                                                        Utils::LanguageExtension::None};
+    ClangBackEnd::ProjectPartContainer cppProjectInfo{"project1",
+                                                      {},
+                                                      {},
+                                                      {},
+                                                      {},
+                                                      {},
+                                                      {},
+                                                      Utils::Language::Cxx,
+                                                      Utils::LanguageVersion::CXX98,
+                                                      Utils::LanguageExtension::None};
+};
+
+using ProjectInfos = testing::Types<ClangBackEnd::PchTask, ClangBackEnd::ProjectPartContainer>;
+TYPED_TEST_SUITE(CommandLineBuilder, ProjectInfos);
+
+TYPED_TEST(CommandLineBuilder, AddToolChainArguments)
+{
+    Builder<TypeParam> builder{this->emptyProjectInfo, {"-m64", "-PIC"}, {}};
+
+    ASSERT_THAT(builder.commandLine, AllOf(Contains("-m64"), Contains("-PIC")));
+}
+
+TYPED_TEST(CommandLineBuilder, CTask)
+{
+    this->emptyProjectInfo.language = Utils::Language::C;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::C11;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.c"};
+
+    ASSERT_THAT(
+        builder.commandLine,
+        ElementsAre("clang", "-x", "c-header", "-std=c11", "-nostdinc", "-nostdlibinc", "/source/file.c"));
+}
+
+TYPED_TEST(CommandLineBuilder, ObjectiveCTask)
+{
+    this->emptyProjectInfo.language = Utils::Language::C;
+    this->emptyProjectInfo.languageExtension = Utils::LanguageExtension::ObjectiveC;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::C11;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.c"};
+
+    ASSERT_THAT(builder.commandLine,
+                ElementsAre("clang",
+                            "-x",
+                            "objective-c-header",
+                            "-std=c11",
+                            "-nostdinc",
+                            "-nostdlibinc",
+                            "/source/file.c"));
+}
+
+TYPED_TEST(CommandLineBuilder, CppTask)
+{
+    this->emptyProjectInfo.language = Utils::Language::Cxx;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::CXX98;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp"};
+
+    ASSERT_THAT(builder.commandLine,
+                ElementsAre("clang++",
+                            "-x",
+                            "c++-header",
+                            "-std=c++98",
+                            "-nostdinc",
+                            "-nostdlibinc",
+                            "/source/file.cpp"));
+}
+
+TYPED_TEST(CommandLineBuilder, ObjectiveCppTask)
+{
+    this->emptyProjectInfo.language = Utils::Language::Cxx;
+    this->emptyProjectInfo.languageExtension = Utils::LanguageExtension::ObjectiveC;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::CXX98;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp"};
+
+    ASSERT_THAT(builder.commandLine,
+                ElementsAre("clang++",
+                            "-x",
+                            "objective-c++-header",
+                            "-std=c++98",
+                            "-nostdinc",
+                            "-nostdlibinc",
+                            "/source/file.cpp"));
+}
+
+TYPED_TEST(CommandLineBuilder, Cpp98)
+{
+    this->emptyProjectInfo.language = Utils::Language::Cxx;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::CXX98;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=c++98"));
+}
+
+TYPED_TEST(CommandLineBuilder, Cpp03)
+{
+    this->emptyProjectInfo.language = Utils::Language::Cxx;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::CXX03;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=c++03"));
+}
+
+TYPED_TEST(CommandLineBuilder, Cpp11)
+{
+    this->emptyProjectInfo.language = Utils::Language::Cxx;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::CXX11;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=c++11"));
+}
+
+TYPED_TEST(CommandLineBuilder, Cpp14)
+{
+    this->emptyProjectInfo.language = Utils::Language::Cxx;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::CXX14;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=c++14"));
+}
+
+TYPED_TEST(CommandLineBuilder, Cpp17)
+{
+    this->emptyProjectInfo.language = Utils::Language::Cxx;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::CXX17;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=c++17"));
+}
+
+TYPED_TEST(CommandLineBuilder, Cpp20)
+{
+    this->emptyProjectInfo.language = Utils::Language::Cxx;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::CXX2a;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=c++2a"));
+}
+
+TYPED_TEST(CommandLineBuilder, GnuCpp98)
+{
+    this->emptyProjectInfo.language = Utils::Language::Cxx;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::CXX98;
+    this->emptyProjectInfo.languageExtension = Utils::LanguageExtension::Gnu;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=gnu++98"));
+}
+
+TYPED_TEST(CommandLineBuilder, GnuCpp03)
+{
+    this->emptyProjectInfo.language = Utils::Language::Cxx;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::CXX03;
+    this->emptyProjectInfo.languageExtension = Utils::LanguageExtension::Gnu;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=gnu++03"));
+}
+
+TYPED_TEST(CommandLineBuilder, GnuCpp11)
+{
+    this->emptyProjectInfo.language = Utils::Language::Cxx;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::CXX11;
+    this->emptyProjectInfo.languageExtension = Utils::LanguageExtension::Gnu;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=gnu++11"));
+}
+
+TYPED_TEST(CommandLineBuilder, GnuCpp14)
+{
+    this->emptyProjectInfo.language = Utils::Language::Cxx;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::CXX14;
+    this->emptyProjectInfo.languageExtension = Utils::LanguageExtension::Gnu;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=gnu++14"));
+}
+
+TYPED_TEST(CommandLineBuilder, GnuCpp17)
+{
+    this->emptyProjectInfo.language = Utils::Language::Cxx;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::CXX17;
+    this->emptyProjectInfo.languageExtension = Utils::LanguageExtension::Gnu;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=gnu++17"));
+}
+
+TYPED_TEST(CommandLineBuilder, GnuCpp20)
+{
+    this->emptyProjectInfo.language = Utils::Language::Cxx;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::CXX2a;
+    this->emptyProjectInfo.languageExtension = Utils::LanguageExtension::Gnu;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=gnu++2a"));
+}
+
+TYPED_TEST(CommandLineBuilder, C89)
+{
+    this->emptyProjectInfo.language = Utils::Language::C;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::C89;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.c"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=c89"));
+}
+
+TYPED_TEST(CommandLineBuilder, C99)
+{
+    this->emptyProjectInfo.language = Utils::Language::C;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::C99;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.c"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=c99"));
+}
+
+TYPED_TEST(CommandLineBuilder, C11)
+{
+    this->emptyProjectInfo.language = Utils::Language::C;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::C11;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.c"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=c11"));
+}
+
+TYPED_TEST(CommandLineBuilder, C18)
+{
+    this->emptyProjectInfo.language = Utils::Language::C;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::C18;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.c"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=c18"));
+}
+
+TYPED_TEST(CommandLineBuilder, GnuC89)
+{
+    this->emptyProjectInfo.language = Utils::Language::C;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::C89;
+    this->emptyProjectInfo.languageExtension = Utils::LanguageExtension::Gnu;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.c"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=gnu89"));
+}
+
+TYPED_TEST(CommandLineBuilder, GnuC99)
+{
+    this->emptyProjectInfo.language = Utils::Language::C;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::C99;
+    this->emptyProjectInfo.languageExtension = Utils::LanguageExtension::Gnu;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.c"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=gnu99"));
+}
+
+TYPED_TEST(CommandLineBuilder, GnuC11)
+{
+    this->emptyProjectInfo.language = Utils::Language::C;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::C11;
+    this->emptyProjectInfo.languageExtension = Utils::LanguageExtension::Gnu;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.c"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=gnu11"));
+}
+
+TYPED_TEST(CommandLineBuilder, GnuC18)
+{
+    this->emptyProjectInfo.language = Utils::Language::C;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::C18;
+    this->emptyProjectInfo.languageExtension = Utils::LanguageExtension::Gnu;
+
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.c"};
+
+    ASSERT_THAT(builder.commandLine, Contains("-std=gnu18"));
+}
+
+TYPED_TEST(CommandLineBuilder, IncludesOrder)
+{
+    this->emptyProjectInfo.language = Utils::Language::Cxx;
+    this->emptyProjectInfo.languageVersion = Utils::LanguageVersion::CXX11;
+    this->emptyProjectInfo.projectIncludeSearchPaths = {{"/include/bar", 2, IncludeSearchPathType::User},
+                                           {"/include/foo", 1, IncludeSearchPathType::User}};
+    this->emptyProjectInfo.systemIncludeSearchPaths = {{"/system/bar", 4, IncludeSearchPathType::System},
+                                          {"/system/foo", 3, IncludeSearchPathType::Framework},
+                                          {"/builtin/bar", 2, IncludeSearchPathType::BuiltIn},
+                                          {"/builtin/foo", 1, IncludeSearchPathType::BuiltIn}};
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp"};
+
+    ASSERT_THAT(builder.commandLine,
+                ElementsAre("clang++",
+                            "-x",
+                            "c++-header",
+                            "-std=c++11",
+                            "-nostdinc",
+                            "-nostdlibinc",
+                            "-I",
+                            "/include/foo",
+                            "-I",
+                            "/include/bar",
+                            "-F",
+                            "/system/foo",
+                            "-isystem",
+                            "/system/bar",
+                            "-isystem",
+                            "/builtin/foo",
+                            "-isystem",
+                            "/builtin/bar",
+                            "/source/file.cpp"));
+}
+
+TYPED_TEST(CommandLineBuilder, EmptySourceFile)
+{
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, {}};
+
+    ASSERT_THAT(builder.commandLine,
+                ElementsAre("clang++", "-x", "c++-header", "-std=c++98", "-nostdinc", "-nostdlibinc"));
+}
+
+TYPED_TEST(CommandLineBuilder, SourceFile)
+{
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp"};
+
+    ASSERT_THAT(builder.commandLine,
+                ElementsAre("clang++",
+                            "-x",
+                            "c++-header",
+                            "-std=c++98",
+                            "-nostdinc",
+                            "-nostdlibinc",
+                            "/source/file.cpp"));
+}
+
+
+TYPED_TEST(CommandLineBuilder, EmptyOutputFile)
+{
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp", ""};
+
+    ASSERT_THAT(builder.commandLine,
+                ElementsAre("clang++",
+                            "-x",
+                            "c++-header",
+                            "-std=c++98",
+                            "-nostdinc",
+                            "-nostdlibinc",
+                            "/source/file.cpp"));
+}
+
+TYPED_TEST(CommandLineBuilder, OutputFile)
+{
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp", "/output/file.o"};
+
+    ASSERT_THAT(builder.commandLine,
+                ElementsAre("clang++",
+                            "-x",
+                            "c++-header",
+                            "-std=c++98",
+                            "-nostdinc",
+                            "-nostdlibinc",
+                            "-o",
+                            "/output/file.o",
+                            "/source/file.cpp"));
+}
+
+TYPED_TEST(CommandLineBuilder, IncludePchPath)
+{
+    Builder<TypeParam> builder{this->emptyProjectInfo, {}, "/source/file.cpp", "/output/file.o", "/pch/file.pch"};
+
+    ASSERT_THAT(builder.commandLine,
+                ElementsAre("clang++",
+                            "-x",
+                            "c++-header",
+                            "-std=c++98",
+                            "-nostdinc",
+                            "-nostdlibinc",
+                            "-Xclang",
+                            "-include-pch",
+                            "-Xclang",
+                            "/pch/file.pch",
+                            "-o",
+                            "/output/file.o",
+                            "/source/file.cpp"));
+}
+
+} // namespace
diff --git a/tests/unit/unittest/google-using-declarations.h b/tests/unit/unittest/google-using-declarations.h
index fbf4e249f4..e8bbd52800 100644
--- a/tests/unit/unittest/google-using-declarations.h
+++ b/tests/unit/unittest/google-using-declarations.h
@@ -38,6 +38,7 @@ using testing::Assign;
 using testing::ByMove;
 using testing::ByRef;
 using testing::Contains;
+using testing::ContainerEq;
 using testing::ElementsAre;
 using testing::Field;
 using testing::HasSubstr;
diff --git a/tests/unit/unittest/googletest.h b/tests/unit/unittest/googletest.h
index e5d221d6a8..b685b83c78 100644
--- a/tests/unit/unittest/googletest.h
+++ b/tests/unit/unittest/googletest.h
@@ -33,6 +33,7 @@
 #include <gmock/gmock-matchers.h>
 #include <gtest/gtest.h>
 #include <gtest/gtest-printers.h>
+#include <gtest/gtest-typed-test.h>
 
 #include "compare-operators.h"
 
diff --git a/tests/unit/unittest/gtest-creator-printing.cpp b/tests/unit/unittest/gtest-creator-printing.cpp
index 36e9cdf891..8b2fbcd226 100644
--- a/tests/unit/unittest/gtest-creator-printing.cpp
+++ b/tests/unit/unittest/gtest-creator-printing.cpp
@@ -42,6 +42,7 @@
 #include <filestatus.h>
 #include <filepath.h>
 #include <fulltokeninfo.h>
+#include <includesearchpath.h>
 #include <nativefilepath.h>
 #include <pchcreator.h>
 #include <pchtask.h>
@@ -56,6 +57,7 @@
 #include <symbolindexertaskqueue.h>
 #include <symbol.h>
 #include <tooltipinfo.h>
+#include <toolchainargumentscache.h>
 #include <projectpartentry.h>
 #include <usedmacro.h>
 
@@ -181,6 +183,100 @@ std::ostream &operator<<(std::ostream &out, const LineColumn &lineColumn)
     return out << "(" << lineColumn.line << ", " << lineColumn.column << ")";
 }
 
+const char * toText(Utils::Language language)
+{
+    using Utils::Language;
+
+    switch (language) {
+    case Language::C:
+        return "C";
+    case Language::Cxx:
+        return "Cxx";
+    }
+
+    return "";
+}
+
+std::ostream &operator<<(std::ostream &out, const Utils::Language &language)
+{
+    return out << "Utils::" << toText(language);
+}
+
+const char * toText(Utils::LanguageVersion languageVersion)
+{
+    using Utils::LanguageVersion;
+
+    switch (languageVersion) {
+    case LanguageVersion::C11:
+        return "C11";
+    case LanguageVersion::C18:
+        return "C18";
+    case LanguageVersion::C89:
+        return "C89";
+    case LanguageVersion::C99:
+        return "C99";
+    case LanguageVersion::CXX03:
+        return "CXX03";
+    case LanguageVersion::CXX11:
+        return "CXX11";
+    case LanguageVersion::CXX14:
+        return "CXX14";
+    case LanguageVersion::CXX17:
+        return "CXX17";
+    case LanguageVersion::CXX2a:
+        return "CXX2a";
+    case LanguageVersion::CXX98:
+        return "CXX98";
+    }
+
+    return "";
+}
+
+std::ostream &operator<<(std::ostream &out, const Utils::LanguageVersion &languageVersion)
+{
+     return out << "Utils::" << toText(languageVersion);
+}
+
+const std::string toText(Utils::LanguageExtension extension, std::string prefix = {})
+{
+    std::stringstream out;
+    using Utils::LanguageExtension;
+
+    if (extension == LanguageExtension::None) {
+        out << prefix << "None";
+    } else if (extension == LanguageExtension::All) {
+        out << prefix << "All";
+    } else {
+        std::string split = "";
+        if (extension == LanguageExtension::Gnu) {
+            out << prefix << "Gnu";
+            split = " | ";
+        }
+        if (extension == LanguageExtension::Microsoft) {
+            out << split << prefix << "Microsoft";
+            split = " | ";
+        }
+        if (extension == LanguageExtension::Borland) {
+            out << split << prefix << "Borland";
+            split = " | ";
+        }
+        if (extension == LanguageExtension::OpenMP) {
+            out << split << prefix << "OpenMP";
+            split = " | ";
+        }
+        if (extension == LanguageExtension::ObjectiveC) {
+            out << split << prefix << "ObjectiveC";
+        }
+    }
+
+    return out.str();
+}
+
+std::ostream &operator<<(std::ostream &out, const Utils::LanguageExtension &languageExtension)
+{
+    return out << toText(languageExtension, "Utils::");
+}
+
 void PrintTo(Utils::SmallStringView text, ::std::ostream *os)
 {
     *os << "\"" << text << "\"";
@@ -1061,7 +1157,15 @@ std::ostream &operator<<(std::ostream &out, const PchCreatorIncludes &includes)
 std::ostream &operator<<(std::ostream &out, const PchTask &task)
 {
     return out << "(" << task.projectPartIds << ", " << task.includes << ", " << task.compilerMacros
-               << ", " << task.usedMacros << ")";
+               << ", " << task.usedMacros << ", " << toText(task.language) << ", "
+               << task.systemIncludeSearchPaths << ", " << task.projectIncludeSearchPaths << ", "
+               << task.toolChainArguments << ", " << toText(task.languageVersion) << ", "
+               << toText(task.languageExtension) << ")";
+}
+
+std::ostream &operator<<(std::ostream &out, const PchTaskSet &taskSet)
+{
+    return out << "(" << taskSet.system << ", " << taskSet.project << ")";
 }
 
 std::ostream &operator<<(std::ostream &out, const BuildDependency &dependency)
@@ -1105,6 +1209,50 @@ std::ostream &operator<<(std::ostream &out, const SourceEntry &entry)
     return out  << "(" << entry.sourceId << ", " << sourceTypeString(entry.sourceType) << ")";
 }
 
+const char *typeToString(IncludeSearchPathType type)
+{
+    switch (type) {
+    case IncludeSearchPathType::Invalid:
+        return "Invalid";
+    case IncludeSearchPathType::User:
+        return "User";
+    case IncludeSearchPathType::System:
+        return "System";
+    case IncludeSearchPathType::BuiltIn:
+        return "BuiltIn";
+    case IncludeSearchPathType::Framework:
+        return "Framework";
+    }
+
+    return nullptr;
+}
+
+std::ostream &operator<<(std::ostream &out, const IncludeSearchPathType &pathType)
+{
+    return out << "IncludeSearchPathType::" << typeToString(pathType);
+}
+
+std::ostream &operator<<(std::ostream &out, const IncludeSearchPath &path)
+{
+    return out << "(" << path.path << ", " << path.index << ", " << typeToString(path.type) << ")";
+}
+
+std::ostream &operator<<(std::ostream &out, const ArgumentsEntry &entry)
+{
+    return out << "(" << entry.ids << ", " << entry.arguments << ")";
+}
+
+std::ostream &operator<<(std::ostream &out, const ProjectPartContainer &container)
+{
+    out << "(" << container.projectPartId << ", " << container.toolChainArguments << ", "
+        << container.headerPathIds << ", " << container.sourcePathIds << ", "
+        << container.compilerMacros << ", " << container.systemIncludeSearchPaths << ", "
+        << container.projectIncludeSearchPaths << ", " << toText(container.language) << ", "
+        << toText(container.languageVersion) << ", " << toText(container.languageExtension) << ")";
+
+    return out;
+}
+
 void PrintTo(const FilePath &filePath, ::std::ostream *os)
 {
     *os << filePath;
@@ -1138,19 +1286,6 @@ std::ostream &operator<<(std::ostream &os, const FileContainer &container)
     return os;
 }
 
-std::ostream &operator<<(std::ostream &out, const ProjectPartContainer &container)
-{
-    out << "("
-        << container.projectPartId << ", "
-        << container.arguments << ", "
-        << container.headerPathIds << ", "
-        << container.sourcePathIds << ", "
-        << container.compilerMacros << ", "
-        << container.includeSearchPaths << ")";
-
-    return out;
-}
-
 std::ostream &operator<<(std::ostream &os, const SourceLocationContainer &container)
 {
     os << "("
diff --git a/tests/unit/unittest/gtest-creator-printing.h b/tests/unit/unittest/gtest-creator-printing.h
index 0f2184fc11..ec54af3085 100644
--- a/tests/unit/unittest/gtest-creator-printing.h
+++ b/tests/unit/unittest/gtest-creator-printing.h
@@ -25,6 +25,7 @@
 
 #pragma once
 
+#include <utils/cpplanguage_details.h>
 #include <utils/smallstringio.h>
 #include <utils/optional.h>
 
@@ -74,6 +75,9 @@ class LineColumn;
 class SmallStringView;
 
 std::ostream &operator<<(std::ostream &out, const LineColumn &lineColumn);
+std::ostream &operator<<(std::ostream &out, const Utils::Language &language);
+std::ostream &operator<<(std::ostream &out, const Utils::LanguageVersion &languageVersion);
+std::ostream &operator<<(std::ostream &out, const Utils::LanguageExtension &languageExtension);
 
 template <typename Type>
 std::ostream &operator<<(std::ostream &out, const Utils::optional<Type> &optional)
@@ -176,10 +180,15 @@ class SymbolIndexerTask;
 class ProgressMessage;
 class PchCreatorIncludes;
 class PchTask;
+class PchTaskSet;
 class BuildDependency;
 class SourceEntry;
 class FilePathCaching;
 class SlotUsage;
+class IncludeSearchPath;
+enum class IncludeSearchPathType : unsigned char;
+class ArgumentsEntry;
+class ProjectPartContainer;
 
 std::ostream &operator<<(std::ostream &out, const SourceLocationEntry &entry);
 std::ostream &operator<<(std::ostream &out, const IdPaths &idPaths);
@@ -262,9 +271,14 @@ std::ostream &operator<<(std::ostream &out, const SymbolIndexerTask &task);
 std::ostream &operator<<(std::ostream &out, const ProgressMessage &message);
 std::ostream &operator<<(std::ostream &out, const PchCreatorIncludes &includes);
 std::ostream &operator<<(std::ostream &out, const PchTask &task);
+std::ostream &operator<<(std::ostream &out, const PchTaskSet &taskSet);
 std::ostream &operator<<(std::ostream &out, const BuildDependency &dependency);
 std::ostream &operator<<(std::ostream &out, const SourceEntry &entry);
 std::ostream &operator<<(std::ostream &out, const SlotUsage &slotUsage);
+std::ostream &operator<<(std::ostream &out, const IncludeSearchPathType &pathType);
+std::ostream &operator<<(std::ostream &out, const IncludeSearchPath &path);
+std::ostream &operator<<(std::ostream &out, const ArgumentsEntry &entry);
+std::ostream &operator<<(std::ostream &out, const ProjectPartContainer &container);
 
 void PrintTo(const FilePath &filePath, ::std::ostream *os);
 void PrintTo(const FilePathView &filePathView, ::std::ostream *os);
@@ -272,12 +286,10 @@ void PrintTo(const FilePathId &filePathId, ::std::ostream *os);
 
 namespace V2 {
 class FileContainer;
-class ProjectPartContainer;
 class SourceRangeContainer;
 class SourceLocationContainer;
 
 std::ostream &operator<<(std::ostream &out, const FileContainer &container);
-std::ostream &operator<<(std::ostream &out, const ProjectPartContainer &container);
 std::ostream &operator<<(std::ostream &out, const SourceLocationContainer &container);
 std::ostream &operator<<(std::ostream &out, const SourceRangeContainer &container);
 }  // namespace V2
diff --git a/tests/unit/unittest/mockbuilddependenciesprovider.h b/tests/unit/unittest/mockbuilddependenciesprovider.h
index 2a1fd8f93f..a4a57db33b 100644
--- a/tests/unit/unittest/mockbuilddependenciesprovider.h
+++ b/tests/unit/unittest/mockbuilddependenciesprovider.h
@@ -34,5 +34,5 @@ class MockBuildDependenciesProvider : public ClangBackEnd::BuildDependenciesProv
 public:
     MOCK_METHOD1(
         create,
-        ClangBackEnd::BuildDependency(const ClangBackEnd::V2::ProjectPartContainer &projectPart));
+        ClangBackEnd::BuildDependency(const ClangBackEnd::ProjectPartContainer &projectPart));
 };
diff --git a/tests/unit/unittest/mockbuilddependencygenerator.h b/tests/unit/unittest/mockbuilddependencygenerator.h
index 91b8a1422d..abd6c223d0 100644
--- a/tests/unit/unittest/mockbuilddependencygenerator.h
+++ b/tests/unit/unittest/mockbuilddependencygenerator.h
@@ -33,6 +33,6 @@ class MockBuildDependencyGenerator : public ClangBackEnd::BuildDependencyGenerat
 {
 public:
     MOCK_METHOD1(create,
-                 ClangBackEnd::BuildDependency (const ClangBackEnd::V2::ProjectPartContainer &projectPart));
+                 ClangBackEnd::BuildDependency (const ClangBackEnd::ProjectPartContainer &projectPart));
 };
 
diff --git a/tests/unit/unittest/mockpchcreator.h b/tests/unit/unittest/mockpchcreator.h
index 992976d4de..86a34ac04f 100644
--- a/tests/unit/unittest/mockpchcreator.h
+++ b/tests/unit/unittest/mockpchcreator.h
@@ -30,18 +30,21 @@
 #include <filecontainerv2.h>
 #include <pchcreatorinterface.h>
 #include <projectpartpch.h>
-#include <projectpartcontainerv2.h>
+#include <projectpartcontainer.h>
 
 class MockPchCreator : public ClangBackEnd::PchCreatorInterface
 {
 public:
-    MOCK_METHOD1(generatePchDeprecated, void(const ClangBackEnd::V2::ProjectPartContainer &projectPart));
     MOCK_METHOD1(generatePch, void(const ClangBackEnd::PchTask &pchTask));
-    MOCK_METHOD0(takeProjectIncludes, ClangBackEnd::IdPaths());
     MOCK_METHOD0(projectPartPch, const ClangBackEnd::ProjectPartPch &());
     MOCK_METHOD1(setUnsavedFiles, void(const ClangBackEnd::V2::FileContainers &fileContainers));
     MOCK_METHOD0(clear, void());
     MOCK_METHOD0(doInMainThreadAfterFinished, void());
     MOCK_CONST_METHOD0(isUsed, bool());
     MOCK_METHOD1(setIsUsed, void(bool));
+
+    void generatePch(ClangBackEnd::PchTask &&pchTask) override
+    {
+        generatePch(pchTask);
+    }
 };
diff --git a/tests/unit/unittest/mockpchtaskgenerator.h b/tests/unit/unittest/mockpchtaskgenerator.h
new file mode 100644
index 0000000000..4934d7a9a6
--- /dev/null
+++ b/tests/unit/unittest/mockpchtaskgenerator.h
@@ -0,0 +1,46 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include "googletest.h"
+
+#include <pchtaskgeneratorinterface.h>
+
+class MockPchTaskGenerator : public ClangBackEnd::PchTaskGeneratorInterface
+{
+public:
+    MOCK_METHOD2(addProjectParts,
+                 void(const ClangBackEnd::ProjectPartContainers &projectParts,
+                      const Utils::SmallStringVector &toolChainArguments));
+    MOCK_METHOD1(removeProjectParts,
+                 void (const Utils::SmallStringVector &projectsPartIds));
+
+    void addProjectParts(ClangBackEnd::ProjectPartContainers &&projectParts,
+                         Utils::SmallStringVector &&toolChainArguments) override
+    {
+        addProjectParts(projectParts, toolChainArguments);
+    }
+};
diff --git a/tests/unit/unittest/mockpchtasksmerger.h b/tests/unit/unittest/mockpchtasksmerger.h
index c320159d34..39e73f9f55 100644
--- a/tests/unit/unittest/mockpchtasksmerger.h
+++ b/tests/unit/unittest/mockpchtasksmerger.h
@@ -32,7 +32,15 @@
 class MockPchTasksMerger : public ClangBackEnd::PchTasksMergerInterface
 {
 public:
-    MOCK_METHOD1(mergeTasks, void(const ClangBackEnd::PchTaskSets &pchTaskSets));
+    MOCK_METHOD2(mergeTasks,
+                 void(const ClangBackEnd::PchTaskSets &pchTaskSets,
+                      const Utils::SmallStringVector &toolChainArguments));
 
-    void mergeTasks(ClangBackEnd::PchTaskSets &&pchTaskSets) override { mergeTasks(pchTaskSets); }
+    MOCK_METHOD1(removePchTasks, void(const Utils::SmallStringVector &projectPartIds));
+
+    void mergeTasks(ClangBackEnd::PchTaskSets &&pchTaskSets,
+                    Utils::SmallStringVector &&toolChainArguments) override
+    {
+        mergeTasks(pchTaskSets, toolChainArguments);
+    }
 };
diff --git a/tests/unit/unittest/mockprecompiledheaderstorage.h b/tests/unit/unittest/mockprecompiledheaderstorage.h
index c267ecb535..a2bc0fddf0 100644
--- a/tests/unit/unittest/mockprecompiledheaderstorage.h
+++ b/tests/unit/unittest/mockprecompiledheaderstorage.h
@@ -37,11 +37,12 @@ public:
                       Utils::SmallStringView pchPath,
                       long long pchBuildTime));
     MOCK_METHOD1(deleteProjectPrecompiledHeader, void(Utils::SmallStringView projectPartName));
-    MOCK_METHOD3(insertSystemPrecompiledHeader,
-                 void(Utils::SmallStringView projectPartName,
+    MOCK_METHOD3(insertSystemPrecompiledHeaders,
+                 void(const Utils::SmallStringVector &projectPartNames,
                       Utils::SmallStringView pchPath,
                       long long pchBuildTime));
-    MOCK_METHOD1(deleteSystemPrecompiledHeader, void(Utils::SmallStringView projectPartName));
+    MOCK_METHOD1(deleteSystemPrecompiledHeaders,
+                 void(const Utils::SmallStringVector &projectPartNames));
     MOCK_METHOD1(fetchSystemPrecompiledHeaderPath,
-                 Utils::PathString(Utils::SmallStringView projectPartName));
+                 ClangBackEnd::FilePath(Utils::SmallStringView projectPartName));
 };
diff --git a/tests/unit/unittest/mockprojectpartqueue.h b/tests/unit/unittest/mockprojectpartqueue.h
index 8d1ec1f66c..022878c73a 100644
--- a/tests/unit/unittest/mockprojectpartqueue.h
+++ b/tests/unit/unittest/mockprojectpartqueue.h
@@ -33,13 +33,13 @@ class MockProjectPartQueue : public ClangBackEnd::ProjectPartQueueInterface
 {
 public:
     MOCK_METHOD1(addProjectParts,
-                 void (const ClangBackEnd::V2::ProjectPartContainers &projectParts));
+                 void (const ClangBackEnd::ProjectPartContainers &projectParts));
     MOCK_METHOD1(removeProjectParts,
                  void (const Utils::SmallStringVector &projectsPartIds));
 
     MOCK_METHOD0(processEntries, void ());
 
-    void addProjectParts(ClangBackEnd::V2::ProjectPartContainers &&projectParts) override
+    void addProjectParts(ClangBackEnd::ProjectPartContainers &&projectParts) override
     {
         addProjectParts(projectParts);
     }
diff --git a/tests/unit/unittest/mockprojectparts.h b/tests/unit/unittest/mockprojectparts.h
index 611e12b9fe..f81eabc91c 100644
--- a/tests/unit/unittest/mockprojectparts.h
+++ b/tests/unit/unittest/mockprojectparts.h
@@ -33,13 +33,13 @@ class MockProjectParts : public ClangBackEnd::ProjectPartsInterface
 {
 public:
     MOCK_METHOD1(update,
-                 ClangBackEnd::V2::ProjectPartContainers(const ClangBackEnd::V2::ProjectPartContainers &projectsParts));
+                 ClangBackEnd::ProjectPartContainers(const ClangBackEnd::ProjectPartContainers &projectsParts));
     MOCK_METHOD1(remove,
                  void(const Utils::SmallStringVector &projectPartIds));
     MOCK_CONST_METHOD1(projects,
-                       ClangBackEnd::V2::ProjectPartContainers(const Utils::SmallStringVector &projectPartIds));
+                       ClangBackEnd::ProjectPartContainers(const Utils::SmallStringVector &projectPartIds));
 
-    ClangBackEnd::V2::ProjectPartContainers update(ClangBackEnd::V2::ProjectPartContainers &&projectsParts) override
+    ClangBackEnd::ProjectPartContainers update(ClangBackEnd::ProjectPartContainers &&projectsParts) override
     {
         return update(projectsParts);
     }
diff --git a/tests/unit/unittest/mocksqlitereadstatement.cpp b/tests/unit/unittest/mocksqlitereadstatement.cpp
index 128b3d899f..79fb9879b7 100644
--- a/tests/unit/unittest/mocksqlitereadstatement.cpp
+++ b/tests/unit/unittest/mocksqlitereadstatement.cpp
@@ -145,15 +145,22 @@ MockSqliteReadStatement::value<Utils::PathString>(const Utils::SmallStringView &
 }
 
 template <>
+Utils::optional<ClangBackEnd::FilePath>
+MockSqliteReadStatement::value<ClangBackEnd::FilePath>(const Utils::SmallStringView &path)
+{
+    return valueReturnFilePath(path);
+}
+
+template <>
 Utils::optional<ClangBackEnd::ProjectPartArtefact>
-MockSqliteReadStatement::value<ClangBackEnd::ProjectPartArtefact, 4>(const int& sourceId)
+MockSqliteReadStatement::value<ClangBackEnd::ProjectPartArtefact, 5>(const int& sourceId)
 {
     return valueReturnProjectPartArtefact(sourceId);
 }
 
 template <>
 Utils::optional<ClangBackEnd::ProjectPartArtefact>
-MockSqliteReadStatement::value<ClangBackEnd::ProjectPartArtefact, 4>(const Utils::SmallStringView &projectPartName)
+MockSqliteReadStatement::value<ClangBackEnd::ProjectPartArtefact, 5>(const Utils::SmallStringView &projectPartName)
 {
     return valueReturnProjectPartArtefact(projectPartName);
 }
diff --git a/tests/unit/unittest/mocksqlitereadstatement.h b/tests/unit/unittest/mocksqlitereadstatement.h
index 4fbdda2a6d..a5c15e46b7 100644
--- a/tests/unit/unittest/mocksqlitereadstatement.h
+++ b/tests/unit/unittest/mocksqlitereadstatement.h
@@ -99,6 +99,9 @@ public:
     MOCK_METHOD1(valueReturnPathString,
                  Utils::optional<Utils::PathString>(Utils::SmallStringView));
 
+    MOCK_METHOD1(valueReturnFilePath,
+                 Utils::optional<ClangBackEnd::FilePath>(Utils::SmallStringView));
+
     MOCK_METHOD1(valueReturnSmallString,
                  Utils::optional<Utils::SmallString>(int));
 
@@ -213,6 +216,10 @@ Utils::optional<int>
 MockSqliteReadStatement::value<int>(const Utils::PathString&);
 
 template <>
+Utils::optional<ClangBackEnd::FilePath>
+MockSqliteReadStatement::value<ClangBackEnd::FilePath>(const Utils::SmallStringView&);
+
+template <>
 Utils::optional<int>
 MockSqliteReadStatement::value<int>(const int&, const Utils::SmallStringView&);
 
@@ -230,11 +237,11 @@ MockSqliteReadStatement::value<Utils::PathString>(const Utils::SmallStringView&)
 
 template <>
 Utils::optional<ClangBackEnd::ProjectPartArtefact>
-MockSqliteReadStatement::value<ClangBackEnd::ProjectPartArtefact, 4>(const int&);
+MockSqliteReadStatement::value<ClangBackEnd::ProjectPartArtefact, 5>(const int&);
 
 template <>
 Utils::optional<ClangBackEnd::ProjectPartArtefact>
-MockSqliteReadStatement::value<ClangBackEnd::ProjectPartArtefact, 4>(const int&);
+MockSqliteReadStatement::value<ClangBackEnd::ProjectPartArtefact, 5>(const int&);
 
 template <>
 Utils::optional<ClangBackEnd::ProjectPartPch>
diff --git a/tests/unit/unittest/mocksqlitewritestatement.h b/tests/unit/unittest/mocksqlitewritestatement.h
index 8da4db8ef5..7e2cb0270a 100644
--- a/tests/unit/unittest/mocksqlitewritestatement.h
+++ b/tests/unit/unittest/mocksqlitewritestatement.h
@@ -78,6 +78,12 @@ public:
                        Utils::SmallStringView,
                        Utils::SmallStringView));
 
+    MOCK_METHOD5(write,
+                 void (Utils::SmallStringView,
+                      Utils::SmallStringView,
+                      Utils::SmallStringView,
+                      Utils::SmallStringView,
+                      Utils::SmallStringView));
     MOCK_METHOD1(write,
                  void (Utils::SmallStringView));
 
diff --git a/tests/unit/unittest/mocksymbolindexing.h b/tests/unit/unittest/mocksymbolindexing.h
index 048840d976..c502f62d77 100644
--- a/tests/unit/unittest/mocksymbolindexing.h
+++ b/tests/unit/unittest/mocksymbolindexing.h
@@ -33,9 +33,9 @@ class MockSymbolIndexing : public ClangBackEnd::SymbolIndexingInterface
 {
 public:
    MOCK_METHOD1(updateProjectParts,
-                void(const ClangBackEnd::V2::ProjectPartContainers &projectParts));
+                void(const ClangBackEnd::ProjectPartContainers &projectParts));
 
-   void updateProjectParts(ClangBackEnd::V2::ProjectPartContainers &&projectParts) override
+   void updateProjectParts(ClangBackEnd::ProjectPartContainers &&projectParts) override
    {
        updateProjectParts(projectParts);
    }
diff --git a/tests/unit/unittest/mocksymbolstorage.h b/tests/unit/unittest/mocksymbolstorage.h
index c9de142bd4..5b2451bf5a 100644
--- a/tests/unit/unittest/mocksymbolstorage.h
+++ b/tests/unit/unittest/mocksymbolstorage.h
@@ -37,11 +37,12 @@ public:
    MOCK_METHOD2(addSymbolsAndSourceLocations,
                 void(const ClangBackEnd::SymbolEntries &symbolEentries,
                      const ClangBackEnd::SourceLocationEntries &sourceLocations));
-   MOCK_METHOD4(insertOrUpdateProjectPart,
+   MOCK_METHOD5(insertOrUpdateProjectPart,
                 int(Utils::SmallStringView projectPartName,
                     const Utils::SmallStringVector &commandLineArgument,
                     const ClangBackEnd::CompilerMacros &compilerMacros,
-                    const Utils::SmallStringVector &includeSearchPaths));
+                    const ClangBackEnd::IncludeSearchPaths &systemIncludeSearchPaths,
+                    const ClangBackEnd::IncludeSearchPaths &projectIncludeSearchPaths));
    MOCK_METHOD2(updateProjectPartSources,
                 void(int projectPartId,
                      const ClangBackEnd::FilePathIds &sourceFilePathIds));
diff --git a/tests/unit/unittest/modifiedtimechecker-test.cpp b/tests/unit/unittest/modifiedtimechecker-test.cpp
new file mode 100644
index 0000000000..8e0c881b38
--- /dev/null
+++ b/tests/unit/unittest/modifiedtimechecker-test.cpp
@@ -0,0 +1,109 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#include "googletest.h"
+
+#include <filepathcaching.h>
+#include <modifiedtimechecker.h>
+#include <refactoringdatabaseinitializer.h>
+
+namespace {
+
+using ClangBackEnd::SourceEntries;
+using ClangBackEnd::SourceType;
+using ClangBackEnd::FilePathView;
+
+
+class ModifiedTimeChecker : public testing::Test
+{
+protected:
+
+    ClangBackEnd::FilePathId id(const Utils::SmallStringView &path) const
+    {
+        return filePathCache.filePathId(ClangBackEnd::FilePathView{path});
+    }
+
+
+    ModifiedTimeChecker()
+    {
+        ON_CALL(getModifiedTimeCallback, Call(Eq(FilePathView("/path1")))).WillByDefault(Return(50));
+        ON_CALL(getModifiedTimeCallback, Call(Eq(FilePathView("/path2")))).WillByDefault(Return(30));
+    }
+    NiceMock<MockFunction<ClangBackEnd::TimeStamp(ClangBackEnd::FilePathView filePath)>> getModifiedTimeCallback;
+    Sqlite::Database database{":memory:", Sqlite::JournalMode::Memory};
+    ClangBackEnd::RefactoringDatabaseInitializer<Sqlite::Database> databaseInitializer{database};
+    ClangBackEnd::FilePathCaching filePathCache{database};
+    decltype(getModifiedTimeCallback.AsStdFunction()) callback = getModifiedTimeCallback
+                                                                     .AsStdFunction();
+    ClangBackEnd::ModifiedTimeChecker checker{callback, filePathCache};
+    SourceEntries upToDateEntries = {{id("/path1"), SourceType::UserInclude, 100},
+                                     {id("/path2"), SourceType::SystemInclude, 30}};
+    SourceEntries notUpToDateEntries = {{id("/path1"), SourceType::UserInclude, 50},
+                                        {id("/path2"), SourceType::SystemInclude, 20}};
+};
+
+TEST_F(ModifiedTimeChecker, IsUpToDate)
+{
+    auto isUpToDate = checker.isUpToDate(upToDateEntries);
+
+    ASSERT_TRUE(isUpToDate);
+}
+
+TEST_F(ModifiedTimeChecker, IsNotUpToDateIfSourceEntriesAreEmpty)
+{
+    auto isUpToDate = checker.isUpToDate({});
+
+    ASSERT_FALSE(isUpToDate);
+}
+
+TEST_F(ModifiedTimeChecker, IsNotUpToDate)
+{
+    auto isUpToDate = checker.isUpToDate({});
+
+    ASSERT_FALSE(isUpToDate);
+}
+
+TEST_F(ModifiedTimeChecker, PathChangesUpdatesTimeStamps)
+{
+    checker.isUpToDate(upToDateEntries);
+
+    EXPECT_CALL(getModifiedTimeCallback, Call(Eq(FilePathView("/path1"))));
+    EXPECT_CALL(getModifiedTimeCallback, Call(Eq(FilePathView("/path2"))));
+
+    checker.pathsChanged({id(FilePathView("/path1")), id(FilePathView("/path2")), id(FilePathView("/path3"))});
+}
+
+TEST_F(ModifiedTimeChecker, IsNotUpToDateAnyMoreAfterUpdating)
+{
+    checker.isUpToDate(upToDateEntries);
+    ON_CALL(getModifiedTimeCallback, Call(Eq(FilePathView("/path1")))).WillByDefault(Return(120));
+    ON_CALL(getModifiedTimeCallback, Call(Eq(FilePathView("/path2")))).WillByDefault(Return(30));
+
+    checker.pathsChanged({id(FilePathView("/path1")), id(FilePathView("/path2")), id(FilePathView("/path3"))});
+
+    ASSERT_FALSE(checker.isUpToDate(upToDateEntries));
+}
+
+} // namespace
diff --git a/tests/unit/unittest/pchcreator-test.cpp b/tests/unit/unittest/pchcreator-test.cpp
index 8b556af6b7..68c67ecdd5 100644
--- a/tests/unit/unittest/pchcreator-test.cpp
+++ b/tests/unit/unittest/pchcreator-test.cpp
@@ -50,22 +50,25 @@ using ClangBackEnd::FilePathIds;
 using ClangBackEnd::FilePathView;
 using ClangBackEnd::GeneratedFiles;
 using ClangBackEnd::IdPaths;
+using ClangBackEnd::IncludeSearchPathType;
+using ClangBackEnd::PchTask;
 using ClangBackEnd::ProjectPartPch;
 using ClangBackEnd::SourceEntries;
 using ClangBackEnd::SourceEntry;
 using ClangBackEnd::SourceType;
 using ClangBackEnd::V2::FileContainer;
-using ClangBackEnd::V2::ProjectPartContainer;
+using ClangBackEnd::ProjectPartContainer;
 
 using Utils::PathString;
 using Utils::SmallString;
 
 using UnitTests::EndsWith;
 
-MATCHER_P2(HasIdAndType, sourceId, sourceType,
-           std::string(negation ? "hasn't" : "has") +
-               PrintToString(ClangBackEnd::SourceEntry(sourceId, sourceType,
-                                                       -1)))
+MATCHER_P2(HasIdAndType,
+           sourceId,
+           sourceType,
+           std::string(negation ? "hasn't" : "has")
+               + PrintToString(ClangBackEnd::SourceEntry(sourceId, sourceType, -1)))
 {
     const ClangBackEnd::SourceEntry &entry = arg;
     return entry.sourceId == sourceId && entry.sourceType == sourceType;
@@ -74,7 +77,7 @@ MATCHER_P2(HasIdAndType, sourceId, sourceType,
 class PchCreator: public ::testing::Test
 {
 protected:
-    void SetUp()
+    PchCreator()
     {
         creator.setUnsavedFiles({generatedFile});
     }
@@ -96,86 +99,26 @@ protected:
     TestEnvironment environment;
     FileContainer generatedFile{{TESTDATA_DIR, generatedFileName}, "#pragma once", {}};
     NiceMock<MockPchManagerClient> mockPchManagerClient;
-    NiceMock<MockClangPathWatcher> mockClangPathWatcher;
-    ClangBackEnd::PchCreator creator{environment, database, mockPchManagerClient, mockClangPathWatcher};
-    ProjectPartContainer projectPart1{"project1",
-                                      {"-I", TESTDATA_DIR, "-I", TESTDATA_DIR "/builddependencycollector/external", "-I", TESTDATA_DIR "/builddependencycollector/project", "-isystem", TESTDATA_DIR "/builddependencycollector/system", "-Wno-pragma-once-outside-header"},
-                                      {{"DEFINE", "1", 1}},
-                                      {TESTDATA_DIR "/builddependencycollector/external", TESTDATA_DIR "/builddependencycollector/project"},
-                                      {id(header1Path)},
-                                      {id(main1Path)}};
-    ProjectPartContainer projectPart2{"project2",
-                                      {"-I", TESTDATA_DIR, "-I", TESTDATA_DIR "/builddependencycollector/external", "-I", TESTDATA_DIR "/builddependencycollector/project", "-x", "c++-header", "-Wno-pragma-once-outside-header"},
-                                      {{"DEFINE", "1", 1}},
-                                      {TESTDATA_DIR "/builddependencycollector/external", TESTDATA_DIR "/builddependencycollector/project"},
-                                      {id(header2Path)},
-                                      {id(main2Path)}};
+    ClangBackEnd::PchCreator creator{environment, database, mockPchManagerClient};
+    PchTask pchTask1{
+        "project1",
+        {id(TESTDATA_DIR "/builddependencycollector/project/header2.h"),
+         id(TESTDATA_DIR "/builddependencycollector/external/external1.h"),
+         id(TESTDATA_DIR "/builddependencycollector/external/external2.h")},
+        {},
+        {},
+        {},
+        {{TESTDATA_DIR "/builddependencycollector/system", 2, IncludeSearchPathType::BuiltIn},
+         {TESTDATA_DIR "/builddependencycollector/external", 1, IncludeSearchPathType::System}},
+        {{TESTDATA_DIR "/builddependencycollector/project", 1, IncludeSearchPathType::User}},
+    };
 };
 using PchCreatorSlowTest = PchCreator;
 using PchCreatorVerySlowTest = PchCreator;
 
-TEST_F(PchCreator, ConvertToQStringList)
+TEST_F(PchCreator, CreateProjectPartPchFileContent)
 {
-    auto arguments = creator.convertToQStringList({"-I", TESTDATA_DIR});
-
-    ASSERT_THAT(arguments, ElementsAre(QString("-I"), QString(TESTDATA_DIR)));
-}
-
-TEST_F(PchCreator, CreateProjectPartCommandLine)
-{
-    auto commandLine = creator.generateProjectPartCommandLine(projectPart1);
-
-    ASSERT_THAT(commandLine, ElementsAre(environment.clangCompilerPath(), "-I", TESTDATA_DIR, "-I", TESTDATA_DIR "/builddependencycollector/external", "-I", TESTDATA_DIR "/builddependencycollector/project", "-isystem", TESTDATA_DIR "/builddependencycollector/system", "-Wno-pragma-once-outside-header"));
-}
-
-TEST_F(PchCreator, CreateProjectPartHeaders)
-{
-    auto includeIds = creator.generateProjectPartHeaders(projectPart1);
-
-    ASSERT_THAT(includeIds, UnorderedElementsAre(header1Path, generatedFilePath));
-}
-
-TEST_F(PchCreator, CreateProjectPartSources)
-{
-    auto includeIds = creator.generateProjectPartSourcePaths(projectPart1);
-
-    ASSERT_THAT(includeIds, UnorderedElementsAre(main1Path));
-}
-
-TEST_F(PchCreatorSlowTest, CreateProjectPartPchIncludes)
-{
-    using ClangBackEnd::PchCreatorIncludes;
-
-    auto includeIds = creator.generateProjectPartPchIncludes(projectPart1);
-
-    ASSERT_THAT(
-        includeIds,
-        AllOf(
-            Contains(HasIdAndType(
-                id(TESTDATA_DIR "/builddependencycollector/project/header2.h"),
-                SourceType::TopProjectInclude)),
-            Contains(HasIdAndType(
-                id(TESTDATA_DIR "/builddependencycollector/system/system1.h"),
-                SourceType::TopSystemInclude)),
-            Contains(HasIdAndType(
-                id(TESTDATA_DIR
-                   "/builddependencycollector/system/indirect_system.h"),
-                SourceType::SystemInclude)),
-            Contains(HasIdAndType(
-                id(TESTDATA_DIR
-                   "/builddependencycollector/external/external1.h"),
-                SourceType::TopProjectInclude)),
-            Contains(HasIdAndType(
-                id(TESTDATA_DIR
-                   "/builddependencycollector/external/external2.h"),
-                SourceType::TopProjectInclude))));
-}
-
-TEST_F(PchCreatorSlowTest, CreateProjectPartPchFileContent)
-{
-    auto includes = creator.generateProjectPartPchIncludes(projectPart1);
-
-    auto content = creator.generatePchIncludeFileContent(creator.topIncludeIds(includes));
+    auto content = creator.generatePchIncludeFileContent(pchTask1.includes);
 
     ASSERT_THAT(std::string(content),
                 AllOf(HasSubstr("#include \"" TESTDATA_DIR "/builddependencycollector/project/header2.h\"\n"),
@@ -183,11 +126,10 @@ TEST_F(PchCreatorSlowTest, CreateProjectPartPchFileContent)
                       HasSubstr("#include \"" TESTDATA_DIR "/builddependencycollector/external/external2.h\"\n")));
 }
 
-TEST_F(PchCreatorSlowTest, CreateProjectPartPchIncludeFile)
+TEST_F(PchCreator, CreatePchIncludeFile)
 {
-    auto includes = creator.generateProjectPartPchIncludes(projectPart1);
-    auto content = creator.generatePchIncludeFileContent(creator.topIncludeIds(includes));
-    auto pchIncludeFilePath = creator.generateProjectPathPchHeaderFilePath(projectPart1);
+    auto content = creator.generatePchIncludeFileContent(pchTask1.includes);
+    auto pchIncludeFilePath = creator.generatePchHeaderFilePath();
     auto file = creator.generateFileWithContent(pchIncludeFilePath, content);
     file->open(QIODevice::ReadOnly);
 
@@ -199,38 +141,63 @@ TEST_F(PchCreatorSlowTest, CreateProjectPartPchIncludeFile)
                       HasSubstr("#include \"" TESTDATA_DIR "/builddependencycollector/external/external2.h\"\n")));
 }
 
-TEST_F(PchCreator, CreateProjectPartPchCompilerArguments)
-{
-    auto arguments = creator.generateProjectPartPchCompilerArguments(projectPart1);
-
-    ASSERT_THAT(arguments, AllOf(Contains("-x"),
-                                 Contains("c++-header"),
-                                 Contains("-Xclang"),
-                                 Contains("-emit-pch"),
-                                 Contains("-o"),
-                                 Contains(EndsWith(".pch"))));
-}
-
 TEST_F(PchCreator, CreateProjectPartClangCompilerArguments)
 {
-    auto arguments = creator.generateProjectPartClangCompilerArguments(projectPart1);
-
-    ASSERT_THAT(arguments, AllOf(Contains(TESTDATA_DIR),
-                                 Contains("-emit-pch"),
-                                 Contains("-o"),
-                                 Not(Contains(environment.clangCompilerPath()))));
-}
-
-TEST_F(PchCreatorVerySlowTest, IncludesForCreatePchsForProjectParts)
-{
-    creator.generatePchDeprecated(projectPart1);
-
-    ASSERT_THAT(creator.takeProjectIncludes().id, "project1");
+    auto arguments = creator.generateClangCompilerArguments(std::move(pchTask1),
+                                                            "project.h",
+                                                            "project.pch");
+
+    ASSERT_THAT(arguments,
+                ElementsAre("clang++",
+                            "-x",
+                            "c++-header",
+                            "-std=c++98",
+                            "-nostdinc",
+                            "-nostdlibinc",
+                            "-I",
+                            TESTDATA_DIR "/builddependencycollector/project",
+                            "-isystem",
+                            TESTDATA_DIR "/builddependencycollector/external",
+                            "-isystem",
+                            TESTDATA_DIR "/builddependencycollector/system",
+                            "-o",
+                            "project.pch",
+                            "project.h"));
+}
+
+TEST_F(PchCreator, CreateProjectPartClangCompilerArgumentsWithSystemPch)
+{
+    pchTask1.systemPchPath = "system.pch";
+
+    auto arguments = creator.generateClangCompilerArguments(std::move(pchTask1),
+                                                            "project.h",
+                                                            "project.pch");
+
+    ASSERT_THAT(arguments,
+                ElementsAre("clang++",
+                            "-x",
+                            "c++-header",
+                            "-std=c++98",
+                            "-nostdinc",
+                            "-nostdlibinc",
+                            "-I",
+                            TESTDATA_DIR "/builddependencycollector/project",
+                            "-isystem",
+                            TESTDATA_DIR "/builddependencycollector/external",
+                            "-isystem",
+                            TESTDATA_DIR "/builddependencycollector/system",
+                            "-Xclang",
+                            "-include-pch",
+                            "-Xclang",
+                            "system.pch",
+                            "-o",
+                            "project.pch",
+                            "project.h"));
 }
 
 TEST_F(PchCreatorVerySlowTest, ProjectPartPchsSendToPchManagerClient)
 {
-    creator.generatePchDeprecated(projectPart1);
+    creator.generatePch(std::move(pchTask1));
 
     EXPECT_CALL(mockPchManagerClient,
                 precompiledHeadersUpdated(
@@ -240,30 +207,10 @@ TEST_F(PchCreatorVerySlowTest, ProjectPartPchsSendToPchManagerClient)
     creator.doInMainThreadAfterFinished();
 }
 
-TEST_F(PchCreatorVerySlowTest, UpdateFileWatcherIncludes)
-{
-    creator.generatePchDeprecated(projectPart1);
-
-    EXPECT_CALL(mockClangPathWatcher,
-                updateIdPaths(ElementsAre(creator.projectIncludes())));
-
-    creator.doInMainThreadAfterFinished();
-}
 
-TEST_F(PchCreatorVerySlowTest, IdPathsForCreatePchsForProjectParts)
+TEST_F(PchCreatorVerySlowTest, ProjectPartPchForCreatesPchForPchTask)
 {
-    creator.generatePchDeprecated(projectPart1);
-
-    ASSERT_THAT(creator.takeProjectIncludes(),
-                AllOf(Field(&IdPaths::id, "project1"),
-                      Field(&IdPaths::filePathIds, AllOf(Contains(id(TESTDATA_DIR "/builddependencycollector/project/header2.h")),
-                                                         Contains(id(TESTDATA_DIR "/builddependencycollector/external/external1.h")),
-                                                         Contains(id(TESTDATA_DIR "/builddependencycollector/external/external2.h"))))));
-}
-
-TEST_F(PchCreatorVerySlowTest, ProjectPartPchForCreatesPchForProjectPart)
-{
-    creator.generatePchDeprecated(projectPart1);
+    creator.generatePch(std::move(pchTask1));
 
     ASSERT_THAT(creator.projectPartPch(),
                 AllOf(Field(&ProjectPartPch::projectPartId, Eq("project1")),
@@ -273,52 +220,29 @@ TEST_F(PchCreatorVerySlowTest, ProjectPartPchForCreatesPchForProjectPart)
 
 TEST_F(PchCreatorVerySlowTest, ProjectPartPchCleared)
 {
-    creator.generatePchDeprecated(projectPart1);
+    creator.generatePch(std::move(pchTask1));
 
     creator.clear();
 
     ASSERT_THAT(creator.projectPartPch(), ClangBackEnd::ProjectPartPch{});
 }
 
-
-TEST_F(PchCreatorVerySlowTest, ProjectIncludesCleared)
-{
-    creator.generatePchDeprecated(projectPart1);
-
-    creator.clear();
-
-    ASSERT_THAT(creator.projectIncludes(), ClangBackEnd::IdPaths{});
-}
-
-TEST_F(PchCreatorVerySlowTest, FaultyProjectPartPchForCreatesNoPchForProjectPart)
+TEST_F(PchCreatorVerySlowTest, FaultyProjectPartPchForCreatesFaultyPchForPchTask)
 {
-    ProjectPartContainer faultyProjectPart{"faultyProject",
-                                           {"-I", TESTDATA_DIR},
-                                           {{"DEFINE", "1", 1}},
-                                           {"/includes"},
-                                           {},
-                                           {id(TESTDATA_DIR "/builddependencycollector/project/faulty.cpp")}};
+    PchTask faultyPchTask{"faultyProjectPart",
+                          {id(TESTDATA_DIR "/builddependencycollector/project/faulty.cpp")},
+                          {{"DEFINE", "1", 1}},
+                          {},
+                          {},
+                          {{TESTDATA_DIR "/builddependencycollector/external", 1, IncludeSearchPathType::System}},
+                          {{TESTDATA_DIR "/builddependencycollector/project", 1, IncludeSearchPathType::User}}};
 
-    creator.generatePchDeprecated(faultyProjectPart);
+    creator.generatePch(std::move(faultyPchTask));
 
     ASSERT_THAT(creator.projectPartPch(),
-                AllOf(Field(&ProjectPartPch::projectPartId, Eq("faultyProject")),
+                AllOf(Field(&ProjectPartPch::projectPartId, Eq("faultyProjectPart")),
                       Field(&ProjectPartPch::pchPath, IsEmpty()),
                       Field(&ProjectPartPch::lastModified, Eq(-1))));
 }
 
-TEST_F(PchCreator, CreateProjectPartSourcesContent)
-{
-    auto content = creator.generateProjectPartSourcesContent(projectPart1);
-
-    ASSERT_THAT(content, Eq("#include \"" TESTDATA_DIR "/builddependencycollector/project/main3.cpp\"\n"));
-}
-
-TEST_F(PchCreator, Call)
-{
-    auto content = creator.generateProjectPartSourcesContent(projectPart1);
-
-    ASSERT_THAT(content, Eq("#include \"" TESTDATA_DIR "/builddependencycollector/project/main3.cpp\"\n"));
-}
-
 }
diff --git a/tests/unit/unittest/pchmanagerclient-test.cpp b/tests/unit/unittest/pchmanagerclient-test.cpp
index cec39fc73e..d35e595b04 100644
--- a/tests/unit/unittest/pchmanagerclient-test.cpp
+++ b/tests/unit/unittest/pchmanagerclient-test.cpp
@@ -62,10 +62,10 @@ protected:
     ClangBackEnd::FilePathCaching filePathCache{database};
     ClangPchManager::PchManagerProjectUpdater projectUpdater{mockPchManagerServer, client, filePathCache};
     Utils::SmallString projectPartId{"projectPartId"};
-    Utils::SmallString pchFilePath{"/path/to/pch"};
+    ClangBackEnd::FilePath pchFilePath{"/path/to/pch"};
     PrecompiledHeadersUpdatedMessage message{{{projectPartId.clone(), pchFilePath.clone(), 1}}};
     Utils::SmallString projectPartId2{"projectPartId2"};
-    Utils::SmallString pchFilePath2{"/path/to/pch2"};
+    ClangBackEnd::FilePath pchFilePath2{"/path/to/pch2"};
     PrecompiledHeadersUpdatedMessage message2{{{projectPartId2.clone(), pchFilePath2.clone(), 1}}};
 };
 
diff --git a/tests/unit/unittest/pchmanagerclientserverinprocess-test.cpp b/tests/unit/unittest/pchmanagerclientserverinprocess-test.cpp
index 13a4ad3437..a16b3981e4 100644
--- a/tests/unit/unittest/pchmanagerclientserverinprocess-test.cpp
+++ b/tests/unit/unittest/pchmanagerclientserverinprocess-test.cpp
@@ -49,7 +49,7 @@ using ClangBackEnd::UpdateProjectPartsMessage;
 using ClangBackEnd::RemoveGeneratedFilesMessage;
 using ClangBackEnd::RemoveProjectPartsMessage;
 using ClangBackEnd::V2::FileContainer;
-using ClangBackEnd::V2::ProjectPartContainer;
+using ClangBackEnd::ProjectPartContainer;
 using ClangBackEnd::PrecompiledHeadersUpdatedMessage;
 
 using ::testing::Args;
@@ -97,13 +97,18 @@ TEST_F(PchManagerClientServerInProcess, SendAliveMessage)
 
 TEST_F(PchManagerClientServerInProcess, SendUpdateProjectPartsMessage)
 {
-    ProjectPartContainer projectPart2{"projectPartId",
-                                      {"-x", "c++-header", "-Wno-pragma-once-outside-header"},
-                                      {{"DEFINE", "1", 1}},
-                                      {"/includes"},
-                                      {{1, 1}},
-                                      {{1, 2}}};
-    UpdateProjectPartsMessage message{{projectPart2}};
+    ProjectPartContainer projectPart2{
+        "projectPartId",
+        {"-x", "c++-header", "-Wno-pragma-once-outside-header"},
+        {{"DEFINE", "1", 1}},
+        {{"/includes", 1, ClangBackEnd::IncludeSearchPathType::BuiltIn}},
+        {{"/project/includes", 1, ClangBackEnd::IncludeSearchPathType::User}},
+        {{1, 1}},
+        {{1, 2}},
+        Utils::Language::C,
+        Utils::LanguageVersion::C11,
+        Utils::LanguageExtension::All};
+    UpdateProjectPartsMessage message{{projectPart2}, {"-m32"}};
 
     EXPECT_CALL(mockPchManagerServer, updateProjectParts(message));
 
diff --git a/tests/unit/unittest/pchmanagerserver-test.cpp b/tests/unit/unittest/pchmanagerserver-test.cpp
index 77106268d1..9aab088b33 100644
--- a/tests/unit/unittest/pchmanagerserver-test.cpp
+++ b/tests/unit/unittest/pchmanagerserver-test.cpp
@@ -27,7 +27,7 @@
 
 #include "mockclangpathwatcher.h"
 #include "mockpchmanagerclient.h"
-#include "mockprojectpartqueue.h"
+#include "mockpchtaskgenerator.h"
 #include "mockprojectparts.h"
 #include "mockgeneratedfiles.h"
 
@@ -46,7 +46,7 @@ using Utils::PathString;
 using Utils::SmallString;
 using ClangBackEnd::V2::FileContainer;
 using ClangBackEnd::V2::FileContainers;
-using ClangBackEnd::V2::ProjectPartContainer;
+using ClangBackEnd::ProjectPartContainer;
 
 class PchManagerServer : public ::testing::Test
 {
@@ -64,14 +64,15 @@ class PchManagerServer : public ::testing::Test
     }
 
 protected:
-    NiceMock<MockProjectPartQueue> mockProjectPartQueue;
+    NiceMock<MockPchTaskGenerator> mockPchTaskGenerator;
     NiceMock<MockClangPathWatcher> mockClangPathWatcher;
     NiceMock<MockProjectParts> mockProjectParts;
     NiceMock<MockGeneratedFiles> mockGeneratedFiles;
     Sqlite::Database database{":memory:", Sqlite::JournalMode::Memory};
     ClangBackEnd::RefactoringDatabaseInitializer<Sqlite::Database> initializer{database};
     ClangBackEnd::FilePathCaching filePathCache{database};
-    ClangBackEnd::PchManagerServer server{mockClangPathWatcher, mockProjectPartQueue, mockProjectParts, mockGeneratedFiles};
+    ClangBackEnd::PchManagerServer server{
+        mockClangPathWatcher, mockPchTaskGenerator, mockProjectParts, mockGeneratedFiles};
     NiceMock<MockPchManagerClient> mockPchManagerClient;
     SmallString projectPartId1 = "project1";
     SmallString projectPartId2 = "project2";
@@ -80,22 +81,33 @@ protected:
     PathString header1Path = TESTDATA_DIR "/BuildDependencyCollector_header1.h";
     PathString header2Path = TESTDATA_DIR "/BuildDependencyCollector_header2.h";
     ClangBackEnd::IdPaths idPath{projectPartId1, {1, 2}};
-    ProjectPartContainer projectPart1{projectPartId1.clone(),
-                                      {"-I", TESTDATA_DIR, "-Wno-pragma-once-outside-header"},
-                                      {{"DEFINE", "1", 1}},
-                                      {"/includes"},
-                                      {id(header1Path)},
-                                      {id(main1Path)}};
-    ProjectPartContainer projectPart2{projectPartId2.clone(),
-                                      {"-x", "c++-header", "-Wno-pragma-once-outside-header"},
-                                      {{"DEFINE", "1", 1}},
-                                      {"/includes"},
-                                      {id(header2Path)},
-                                      {id(main2Path)}};
+    ProjectPartContainer projectPart1{
+        projectPartId1.clone(),
+        {"-I", TESTDATA_DIR, "-Wno-pragma-once-outside-header"},
+        {{"DEFINE", "1", 1}},
+        {{"/includes", 1, ClangBackEnd::IncludeSearchPathType::BuiltIn}},
+        {{"/project/includes", 1, ClangBackEnd::IncludeSearchPathType::User}},
+        {id(header1Path)},
+        {id(main1Path)},
+        Utils::Language::C,
+        Utils::LanguageVersion::C11,
+        Utils::LanguageExtension::All};
+    ProjectPartContainer projectPart2{
+        projectPartId2.clone(),
+        {"-x", "c++-header", "-Wno-pragma-once-outside-header"},
+        {{"DEFINE", "1", 1}},
+        {{"/includes", 1, ClangBackEnd::IncludeSearchPathType::BuiltIn}},
+        {{"/project/includes", 1, ClangBackEnd::IncludeSearchPathType::User}},
+        {id(header2Path)},
+        {id(main2Path)},
+        Utils::Language::C,
+        Utils::LanguageVersion::C11,
+        Utils::LanguageExtension::All};
     std::vector<ProjectPartContainer> projectParts{projectPart1, projectPart2};
         std::vector<ProjectPartContainer> projectParts2{projectPart2};
     FileContainer generatedFile{{"/path/to/", "file"}, "content", {}};
-    ClangBackEnd::UpdateProjectPartsMessage updateProjectPartsMessage{Utils::clone(projectParts)};
+    ClangBackEnd::UpdateProjectPartsMessage updateProjectPartsMessage{
+        Utils::clone(projectParts), {"toolChainArgument"}};
     ClangBackEnd::RemoveProjectPartsMessage removeProjectPartsMessage{{projectPart1.projectPartId.clone(),
                                                                        projectPart2.projectPartId.clone()}};
 };
@@ -104,8 +116,10 @@ TEST_F(PchManagerServer, FilterProjectPartsAndSendThemToQueue)
 {
     InSequence s;
 
-    EXPECT_CALL(mockProjectParts, update(updateProjectPartsMessage.projectsParts)).WillOnce(Return(projectParts2));
-    EXPECT_CALL(mockProjectPartQueue, addProjectParts(Eq(projectParts2)));
+    EXPECT_CALL(mockProjectParts, update(updateProjectPartsMessage.projectsParts))
+        .WillOnce(Return(projectParts2));
+    EXPECT_CALL(
+        mockPchTaskGenerator, addProjectParts(Eq(projectParts2), ElementsAre("toolChainArgument")));
 
     server.updateProjectParts(updateProjectPartsMessage.clone());
 }
@@ -146,14 +160,17 @@ TEST_F(PchManagerServer, SetPathWatcherNotifier)
 {
     EXPECT_CALL(mockClangPathWatcher, setNotifier(_));
 
-    ClangBackEnd::PchManagerServer server{mockClangPathWatcher, mockProjectPartQueue, mockProjectParts, mockGeneratedFiles};
+    ClangBackEnd::PchManagerServer server{mockClangPathWatcher, mockPchTaskGenerator, mockProjectParts, mockGeneratedFiles};
 }
 
 TEST_F(PchManagerServer, UpdateProjectPartQueueByPathIds)
 {
+    server.updateProjectParts(
+        ClangBackEnd::UpdateProjectPartsMessage{{projectPart1}, {"toolChainArgument"}});
+
     EXPECT_CALL(mockProjectParts, projects(ElementsAre(projectPart1.projectPartId)))
-            .WillOnce(Return(std::vector<ClangBackEnd::V2::ProjectPartContainer>{{projectPart1}}));
-    EXPECT_CALL(mockProjectPartQueue, addProjectParts(ElementsAre(projectPart1)));
+            .WillOnce(Return(std::vector<ClangBackEnd::ProjectPartContainer>{{projectPart1}}));
+    EXPECT_CALL(mockPchTaskGenerator, addProjectParts(ElementsAre(projectPart1), ElementsAre("toolChainArgument")));
 
     server.pathsWithIdsChanged({projectPartId1});
 }
@@ -166,4 +183,17 @@ TEST_F(PchManagerServer, SetProgress)
     server.setProgress(20, 30);
 }
 
+
+TEST_F(PchManagerServer, RemoveToolChainsArguments)
+{
+    server.updateProjectParts(
+        ClangBackEnd::UpdateProjectPartsMessage{{projectPart1}, {"toolChainArgument"}});
+
+    EXPECT_CALL(mockPchTaskGenerator, addProjectParts(_, _)).Times(0);
+    server.removeProjectParts(removeProjectPartsMessage.clone());
+
+    server.pathsWithIdsChanged({projectPart1.projectPartId});
+}
+
+
 }
diff --git a/tests/unit/unittest/pchtaskgenerator-test.cpp b/tests/unit/unittest/pchtaskgenerator-test.cpp
index 0cb4c93583..74610f5170 100644
--- a/tests/unit/unittest/pchtaskgenerator-test.cpp
+++ b/tests/unit/unittest/pchtaskgenerator-test.cpp
@@ -32,10 +32,12 @@
 
 namespace {
 
-using ClangBackEnd::BuildDependency;
 using ClangBackEnd::BuildDependencies;
+using ClangBackEnd::BuildDependency;
 using ClangBackEnd::CompilerMacro;
 using ClangBackEnd::FilePathId;
+using ClangBackEnd::IncludeSearchPath;
+using ClangBackEnd::IncludeSearchPathType;
 using ClangBackEnd::PchTask;
 using ClangBackEnd::PchTaskSet;
 using ClangBackEnd::SourceEntries;
@@ -49,21 +51,29 @@ protected:
     NiceMock<MockBuildDependenciesProvider> mockBuildDependenciesProvider;
     NiceMock<MockPchTasksMerger> mockPchTaskMerger;
     ClangBackEnd::PchTaskGenerator generator{mockBuildDependenciesProvider, mockPchTaskMerger};
-    ClangBackEnd::V2::ProjectPartContainer projectPart1{"ProjectPart1",
-                                                        {"--yi"},
-                                                        {{"YI", "1", 1},
-                                                         {"QI", "7", 1},
-                                                         {"ER", "2", 2},
-                                                         {"SAN", "3", 3},
-                                                         {"SE", "4", 4},
-                                                         {"BA", "8", 4},
-                                                         {"WU", "5", 5},
-                                                         {"LUI", "6", 6},
-                                                         {"JIU", "9", 9},
-                                                         {"SHI", "10", 10}},
-                                                        {"/yi"},
-                                                        {{1, 1}},
-                                                        {{1, 2}}};
+    ClangBackEnd::ProjectPartContainer projectPart1{
+        "ProjectPart1",
+        {"--yi"},
+        {{"YI", "1", 1},
+         {"QI", "7", 1},
+         {"ER", "2", 2},
+         {"SAN", "3", 3},
+         {"SE", "4", 4},
+         {"BA", "8", 4},
+         {"WU", "5", 5},
+         {"LUI", "6", 6},
+         {"JIU", "9", 9},
+         {"SHI", "10", 10}},
+        {IncludeSearchPath{"/system/path", 2, IncludeSearchPathType::System},
+         IncludeSearchPath{"/builtin/path", 3, IncludeSearchPathType::BuiltIn},
+         IncludeSearchPath{"/framework/path", 1, IncludeSearchPathType::System}},
+        {IncludeSearchPath{"/to/path1", 1, IncludeSearchPathType::User},
+         IncludeSearchPath{"/to/path2", 2, IncludeSearchPathType::User}},
+        {{1, 1}},
+        {{1, 2}},
+        Utils::Language::Cxx,
+        Utils::LanguageVersion::CXX11,
+        Utils::LanguageExtension::All};
     SourceEntries firstSources{{1, SourceType::ProjectInclude, 1},
                                {2, SourceType::UserInclude, 1},
                                {3, SourceType::TopProjectInclude, 1},
@@ -73,32 +83,68 @@ protected:
     BuildDependency buildDependency{firstSources, usedMacros, {}, {}, {}};
 };
 
-TEST_F(PchTaskGenerator, Create)
+TEST_F(PchTaskGenerator, AddProjectParts)
+{
+    ON_CALL(mockBuildDependenciesProvider, create(_)).WillByDefault(Return(buildDependency));
+
+    EXPECT_CALL(
+        mockPchTaskMerger,
+        mergeTasks(
+            ElementsAre(AllOf(
+                Field(
+                    &PchTaskSet::system,
+                    AllOf(
+                        Field(&PchTask::projectPartIds, ElementsAre("ProjectPart1")),
+                        Field(&PchTask::includes, ElementsAre(5)),
+                        Field(&PchTask::compilerMacros,
+                              ElementsAre(CompilerMacro{"SE", "4", 4}, CompilerMacro{"WU", "5", 5})),
+                        Field(&PchTask::usedMacros, ElementsAre(UsedMacro{"SE", 4}, UsedMacro{"WU", 5})),
+                        Field(&PchTask::systemIncludeSearchPaths,
+                              ElementsAre(
+                                  IncludeSearchPath{"/system/path", 2, IncludeSearchPathType::System},
+                                  IncludeSearchPath{"/builtin/path", 3, IncludeSearchPathType::BuiltIn},
+                                  IncludeSearchPath{"/framework/path", 1, IncludeSearchPathType::System})),
+                        Field(&PchTask::projectIncludeSearchPaths,
+                              ElementsAre(IncludeSearchPath{"/to/path1", 1, IncludeSearchPathType::User},
+                                          IncludeSearchPath{"/to/path2", 2, IncludeSearchPathType::User})),
+                        Field(&PchTask::toolChainArguments, ElementsAre("--yi")),
+                        Field(&PchTask::language, Eq(Utils::Language::Cxx)),
+                        Field(&PchTask::languageVersion, Eq(Utils::LanguageVersion::CXX11)),
+                        Field(&PchTask::languageExtension, Eq(Utils::LanguageExtension::All)))),
+                AllOf(Field(
+                    &PchTaskSet::project,
+                    AllOf(
+                        Field(&PchTask::projectPartIds, ElementsAre("ProjectPart1")),
+                        Field(&PchTask::includes, ElementsAre(3)),
+                        Field(&PchTask::compilerMacros,
+                              ElementsAre(CompilerMacro{"YI", "1", 1}, CompilerMacro{"SAN", "3", 3})),
+                        Field(&PchTask::usedMacros, ElementsAre(UsedMacro{"YI", 1}, UsedMacro{"SAN", 3})),
+                        Field(&PchTask::systemIncludeSearchPaths,
+                              ElementsAre(
+                                  IncludeSearchPath{"/system/path", 2, IncludeSearchPathType::System},
+                                  IncludeSearchPath{"/builtin/path", 3, IncludeSearchPathType::BuiltIn},
+                                  IncludeSearchPath{"/framework/path", 1, IncludeSearchPathType::System})),
+                        Field(&PchTask::projectIncludeSearchPaths,
+                              ElementsAre(IncludeSearchPath{"/to/path1", 1, IncludeSearchPathType::User},
+                                          IncludeSearchPath{"/to/path2", 2, IncludeSearchPathType::User})),
+                        Field(&PchTask::toolChainArguments, ElementsAre("--yi")),
+                        Field(&PchTask::language, Eq(Utils::Language::Cxx)),
+                        Field(&PchTask::languageVersion, Eq(Utils::LanguageVersion::CXX11)),
+                        Field(&PchTask::languageExtension, Eq(Utils::LanguageExtension::All))))))),
+            ElementsAre(Eq("ToolChainArgument"))));
+
+    generator.addProjectParts({projectPart1}, {"ToolChainArgument"});
+}
+
+TEST_F(PchTaskGenerator, RemoveProjectParts)
 {
     ON_CALL(mockBuildDependenciesProvider, create(_)).WillByDefault(Return(buildDependency));
 
-    EXPECT_CALL(mockPchTaskMerger,
-                mergeTasks(ElementsAre(
-                    AllOf(Field(&PchTaskSet::system,
-                                AllOf(Field(&PchTask::projectPartIds, ElementsAre("ProjectPart1")),
-                                      Field(&PchTask::includes, ElementsAre(4, 5)),
-                                      Field(&PchTask::compilerMacros,
-                                            ElementsAre(CompilerMacro{"SE", "4", 4},
-                                                        CompilerMacro{"WU", "5", 5})),
-                                      Field(&PchTask::usedMacros,
-                                            ElementsAre(UsedMacro{"SE", 4}, UsedMacro{"WU", 5})))),
-                          AllOf(Field(&PchTaskSet::project,
-                                      AllOf(Field(&PchTask::projectPartIds,
-                                                  ElementsAre("ProjectPart1")),
-                                            Field(&PchTask::includes, ElementsAre(1, 3)),
-                                            Field(&PchTask::compilerMacros,
-                                                  ElementsAre(CompilerMacro{"YI", "1", 1},
-                                                              CompilerMacro{"SAN", "3", 3})),
-                                            Field(&PchTask::usedMacros,
-                                                  ElementsAre(UsedMacro{"YI", 1},
-                                                              UsedMacro{"SAN", 3})))))))));
+    EXPECT_CALL(
+        mockPchTaskMerger,
+        removePchTasks(ElementsAre("project1", "project2")));
 
-    generator.create({projectPart1});
+    generator.removeProjectParts({"project1", "project2"});
 }
 
 }
diff --git a/tests/unit/unittest/pchtaskqueue-test.cpp b/tests/unit/unittest/pchtaskqueue-test.cpp
index 2ee1bf3cad..aacd881553 100644
--- a/tests/unit/unittest/pchtaskqueue-test.cpp
+++ b/tests/unit/unittest/pchtaskqueue-test.cpp
@@ -35,6 +35,9 @@
 
 namespace {
 
+using ClangBackEnd::IncludeSearchPath;
+using ClangBackEnd::IncludeSearchPaths;
+using ClangBackEnd::IncludeSearchPathType;
 using ClangBackEnd::PchTask;
 using ClangBackEnd::SlotUsage;
 
@@ -52,42 +55,75 @@ protected:
                                      progressCounter,
                                      mockPrecompiledHeaderStorage,
                                      mockSqliteTransactionBackend};
+    IncludeSearchPaths systemIncludeSearchPaths{
+        {"/includes", 1, IncludeSearchPathType::BuiltIn},
+        {"/other/includes", 2, IncludeSearchPathType::System}};
+    IncludeSearchPaths projectIncludeSearchPaths{
+        {"/project/includes", 1, IncludeSearchPathType::User},
+        {"/other/project/includes", 2, IncludeSearchPathType::User}};
     PchTask systemTask1{"ProjectPart1",
                         {1, 2},
                         {{"YI", "1", 1}, {"SAN", "3", 3}},
-                        {{"LIANG", 0}, {"YI", 1}}};
+                        {{"LIANG", 0}, {"YI", 1}},
+                        {"--yi"},
+                        systemIncludeSearchPaths,
+                        projectIncludeSearchPaths};
     PchTask systemTask2{"ProjectPart2",
                         {1, 2},
                         {{"YI", "1", 1}, {"SAN", "3", 3}},
-                        {{"LIANG", 0}, {"YI", 1}}};
+                        {{"LIANG", 0}, {"YI", 1}},
+                        {"--yi"},
+                        systemIncludeSearchPaths,
+                        projectIncludeSearchPaths};
     PchTask systemTask2b{"ProjectPart2",
                          {3, 4},
                          {{"YI", "1", 1}, {"SAN", "3", 3}},
-                         {{"LIANG", 0}, {"YI", 1}}};
+                         {{"LIANG", 0}, {"YI", 1}},
+                         {"--yi"},
+                         systemIncludeSearchPaths,
+                         projectIncludeSearchPaths};
     PchTask systemTask3{"ProjectPart3",
                         {1, 2},
                         {{"YI", "1", 1}, {"SAN", "3", 3}},
-                        {{"LIANG", 0}, {"YI", 1}}};
+                        {{"LIANG", 0}, {"YI", 1}},
+                        {"--yi"},
+                        systemIncludeSearchPaths,
+                        projectIncludeSearchPaths};
     PchTask projectTask1{"ProjectPart1",
                          {11, 12},
                          {{"SE", "4", 4}, {"WU", "5", 5}},
-                         {{"ER", 2}, {"SAN", 3}}};
+                         {{"ER", 2}, {"SAN", 3}},
+                         {"--yi"},
+                         systemIncludeSearchPaths,
+                         projectIncludeSearchPaths};
     PchTask projectTask2{"ProjectPart2",
                          {11, 12},
                          {{"SE", "4", 4}, {"WU", "5", 5}},
-                         {{"ER", 2}, {"SAN", 3}}};
+                         {{"ER", 2}, {"SAN", 3}},
+                         {"--yi"},
+                         systemIncludeSearchPaths,
+                         projectIncludeSearchPaths};
     PchTask projectTask2b{"ProjectPart2",
                           {21, 22},
                           {{"SE", "4", 4}, {"WU", "5", 5}},
-                          {{"ER", 2}, {"SAN", 3}}};
+                          {{"ER", 2}, {"SAN", 3}},
+                          {"--yi"},
+                          systemIncludeSearchPaths,
+                          projectIncludeSearchPaths};
     PchTask projectTask3{"ProjectPart3",
                          {21, 22},
                          {{"SE", "4", 4}, {"WU", "5", 5}},
-                         {{"ER", 2}, {"SAN", 3}}};
+                         {{"ER", 2}, {"SAN", 3}},
+                         {"--yi"},
+                         systemIncludeSearchPaths,
+                         projectIncludeSearchPaths};
     PchTask systemTask4{Utils::SmallStringVector{"ProjectPart1", "ProjectPart3"},
                         {1, 2},
                         {{"YI", "1", 1}, {"SAN", "3", 3}},
-                        {{"LIANG", 0}, {"YI", 1}}};
+                        {{"LIANG", 0}, {"YI", 1}},
+                        {"--yi"},
+                        systemIncludeSearchPaths,
+                        projectIncludeSearchPaths};
 };
 
 TEST_F(PchTaskQueue, AddProjectPchTask)
@@ -111,28 +147,31 @@ TEST_F(PchTaskQueue, AddSystemPchTask)
 TEST_F(PchTaskQueue, AddProjectPchTasksCallsProcessEntriesForSystemTaskSchedulerIsNotBusy)
 {
     InSequence s;
+    queue.addProjectPchTasks({projectTask1, projectTask2});
 
     EXPECT_CALL(mockSytemPchTaskScheduler, slotUsage()).WillRepeatedly(Return(SlotUsage{2, 0}));
     EXPECT_CALL(mockProjectPchTaskScheduler, slotUsage()).WillRepeatedly(Return(SlotUsage{2, 0}));
     EXPECT_CALL(mockProjectPchTaskScheduler, addTasks(SizeIs(2)));
 
-    queue.addProjectPchTasks({projectTask1, projectTask2});
+    queue.processEntries();
 }
 
 TEST_F(PchTaskQueue, AddProjectPchTasksCallsProcessEntriesForSystemTaskSchedulerIsBusy)
 {
     InSequence s;
+    queue.addProjectPchTasks({projectTask1, projectTask2});
 
     EXPECT_CALL(mockSytemPchTaskScheduler, slotUsage()).WillRepeatedly(Return(SlotUsage{2, 1}));
     EXPECT_CALL(mockProjectPchTaskScheduler, slotUsage()).Times(0);
     EXPECT_CALL(mockProjectPchTaskScheduler, addTasks(_)).Times(0);
 
-    queue.addProjectPchTasks({projectTask1, projectTask2});
+    queue.processEntries();
 }
 
 TEST_F(PchTaskQueue, AddSystemPchTasksCallsProcessEntries)
 {
     InSequence s;
+    queue.addSystemPchTasks({projectTask1, projectTask2});
 
     EXPECT_CALL(mockSytemPchTaskScheduler, slotUsage()).WillRepeatedly(Return(SlotUsage{2, 0}));
     EXPECT_CALL(mockSytemPchTaskScheduler, addTasks(SizeIs(2)));
@@ -140,7 +179,7 @@ TEST_F(PchTaskQueue, AddSystemPchTasksCallsProcessEntries)
     EXPECT_CALL(mockProjectPchTaskScheduler, slotUsage()).Times(0);
     EXPECT_CALL(mockProjectPchTaskScheduler, addTasks(_)).Times(0);
 
-    queue.addSystemPchTasks({projectTask1, projectTask2});
+    queue.processEntries();
 }
 
 TEST_F(PchTaskQueue, AddProjectPchTasksCallsProgressCounter)
@@ -250,20 +289,13 @@ TEST_F(PchTaskQueue, CreateProjectTaskFromPchTask)
     auto projectTask = projectTask1;
     projectTask.systemPchPath = "/path/to/pch";
 
-    EXPECT_CALL(mockSqliteTransactionBackend, lock());
-    EXPECT_CALL(mockSqliteTransactionBackend, deferredBegin());
+
     EXPECT_CALL(mockPrecompiledHeaderStorage, fetchSystemPrecompiledHeaderPath(Eq("ProjectPart1")))
-        .WillOnce(Return(Utils::PathString{"/path/to/pch"}));
-    EXPECT_CALL(mockSqliteTransactionBackend, commit());
-    EXPECT_CALL(mockSqliteTransactionBackend, unlock());
+        .WillOnce(Return(ClangBackEnd::FilePath{"/path/to/pch"}));
     EXPECT_CALL(mockPchCreator, generatePch(Eq(projectTask)));
     EXPECT_CALL(mockPchCreator, projectPartPch()).WillOnce(ReturnRef(projectPartPch));
-    EXPECT_CALL(mockSqliteTransactionBackend, lock());
-    EXPECT_CALL(mockSqliteTransactionBackend, immediateBegin());
     EXPECT_CALL(mockPrecompiledHeaderStorage,
                 insertProjectPrecompiledHeader(Eq("ProjectPart1"), Eq("/path/to/pch"), 99));
-    EXPECT_CALL(mockSqliteTransactionBackend, commit());
-    EXPECT_CALL(mockSqliteTransactionBackend, unlock());
 
     tasks.front()(mockPchCreator);
 }
@@ -277,19 +309,11 @@ TEST_F(PchTaskQueue, DeleteProjectPchEntryInDatabaseIfNoPchIsGenerated)
     auto projectTask = projectTask1;
     projectTask.systemPchPath = "/path/to/pch";
 
-    EXPECT_CALL(mockSqliteTransactionBackend, lock());
-    EXPECT_CALL(mockSqliteTransactionBackend, deferredBegin());
     EXPECT_CALL(mockPrecompiledHeaderStorage, fetchSystemPrecompiledHeaderPath(Eq("ProjectPart1")))
-        .WillOnce(Return(Utils::PathString{"/path/to/pch"}));
-    EXPECT_CALL(mockSqliteTransactionBackend, commit());
-    EXPECT_CALL(mockSqliteTransactionBackend, unlock());
+        .WillOnce(Return(ClangBackEnd::FilePath{"/path/to/pch"}));
     EXPECT_CALL(mockPchCreator, generatePch(Eq(projectTask)));
     EXPECT_CALL(mockPchCreator, projectPartPch()).WillOnce(ReturnRef(projectPartPch));
-    EXPECT_CALL(mockSqliteTransactionBackend, lock());
-    EXPECT_CALL(mockSqliteTransactionBackend, immediateBegin());
     EXPECT_CALL(mockPrecompiledHeaderStorage, deleteProjectPrecompiledHeader(Eq("ProjectPart1")));
-    EXPECT_CALL(mockSqliteTransactionBackend, commit());
-    EXPECT_CALL(mockSqliteTransactionBackend, unlock());
 
     tasks.front()(mockPchCreator);
 }
@@ -310,14 +334,10 @@ TEST_F(PchTaskQueue, CreateSystemTaskFromPchTask)
 
     EXPECT_CALL(mockPchCreator, generatePch(Eq(systemTask4)));
     EXPECT_CALL(mockPchCreator, projectPartPch()).WillOnce(ReturnRef(projectPartPch));
-    EXPECT_CALL(mockSqliteTransactionBackend, lock());
-    EXPECT_CALL(mockSqliteTransactionBackend, immediateBegin());
     EXPECT_CALL(mockPrecompiledHeaderStorage,
-                insertSystemPrecompiledHeader(Eq("ProjectPart1"), Eq("/path/to/pch"), 99));
-    EXPECT_CALL(mockPrecompiledHeaderStorage,
-                insertSystemPrecompiledHeader(Eq("ProjectPart3"), Eq("/path/to/pch"), 99));
-    EXPECT_CALL(mockSqliteTransactionBackend, commit());
-    EXPECT_CALL(mockSqliteTransactionBackend, unlock());
+                insertSystemPrecompiledHeaders(UnorderedElementsAre("ProjectPart1", "ProjectPart3"),
+                                               Eq("/path/to/pch"),
+                                               99));
 
     tasks.front()(mockPchCreator);
 }
@@ -331,12 +351,8 @@ TEST_F(PchTaskQueue, DeleteSystemPchEntryInDatabaseIfNoPchIsGenerated)
 
     EXPECT_CALL(mockPchCreator, generatePch(Eq(systemTask4)));
     EXPECT_CALL(mockPchCreator, projectPartPch()).WillOnce(ReturnRef(projectPartPch));
-    EXPECT_CALL(mockSqliteTransactionBackend, lock());
-    EXPECT_CALL(mockSqliteTransactionBackend, immediateBegin());
-    EXPECT_CALL(mockPrecompiledHeaderStorage, deleteSystemPrecompiledHeader(Eq("ProjectPart1")));
-    EXPECT_CALL(mockPrecompiledHeaderStorage, deleteSystemPrecompiledHeader(Eq("ProjectPart3")));
-    EXPECT_CALL(mockSqliteTransactionBackend, commit());
-    EXPECT_CALL(mockSqliteTransactionBackend, unlock());
+    EXPECT_CALL(mockPrecompiledHeaderStorage,
+                deleteSystemPrecompiledHeaders(UnorderedElementsAre("ProjectPart1", "ProjectPart3")));
 
     tasks.front()(mockPchCreator);
 }
diff --git a/tests/unit/unittest/pchtasksmerger-test.cpp b/tests/unit/unittest/pchtasksmerger-test.cpp
index 8331e69009..6319389e73 100644
--- a/tests/unit/unittest/pchtasksmerger-test.cpp
+++ b/tests/unit/unittest/pchtasksmerger-test.cpp
@@ -29,16 +29,21 @@
 
 #include <pchtasksmerger.h>
 
+namespace {
+
+using ClangBackEnd::IncludeSearchPath;
+using ClangBackEnd::IncludeSearchPathType;
 using ClangBackEnd::PchTask;
 using ClangBackEnd::PchTaskSet;
 
 class PchTasksMerger : public testing::Test
 {
 protected:
-    template<class T>
-    T clone(T entry)
+    PchTask clone(PchTask entry) const
     {
-        return *&entry;
+        // entry.toolChainArguments = toolChainArguments;
+
+        return entry;
     }
 
 protected:
@@ -47,19 +52,44 @@ protected:
     PchTask systemTask1{"ProjectPart1",
                         {1, 2},
                         {{"YI", "1", 1}, {"SAN", "3", 3}},
-                        {{"LIANG", 0}, {"YI", 1}}};
+                        {{"LIANG", 0}, {"YI", 1}},
+                        {"--yi"},
+                        {IncludeSearchPath{"/system/path", 2, IncludeSearchPathType::System},
+                         IncludeSearchPath{"/builtin/path", 3, IncludeSearchPathType::BuiltIn},
+                         IncludeSearchPath{"/framework/path", 1, IncludeSearchPathType::System}},
+                        {IncludeSearchPath{"/to/path1", 1, IncludeSearchPathType::User},
+                         IncludeSearchPath{"/to/path2", 2, IncludeSearchPathType::User}}};
     PchTask projectTask1{"ProjectPart1",
                          {11, 12},
                          {{"SE", "4", 4}, {"WU", "5", 5}},
-                         {{"ER", 2}, {"SAN", 3}}};
+                         {{"ER", 2}, {"SAN", 3}},
+                         {"--yi"},
+                         {IncludeSearchPath{"/system/path", 2, IncludeSearchPathType::System},
+                          IncludeSearchPath{"/builtin/path", 3, IncludeSearchPathType::BuiltIn},
+                          IncludeSearchPath{"/framework/path", 1, IncludeSearchPathType::System}},
+                         {IncludeSearchPath{"/to/path1", 1, IncludeSearchPathType::User},
+                          IncludeSearchPath{"/to/path2", 2, IncludeSearchPathType::User}}};
     PchTask systemTask2{"ProjectPart2",
                         {1, 2},
                         {{"YI", "1", 1}, {"SAN", "3", 3}},
-                        {{"LIANG", 0}, {"YI", 1}}};
+                        {{"LIANG", 0}, {"YI", 1}},
+                        {"--yi"},
+                        {IncludeSearchPath{"/system/path", 2, IncludeSearchPathType::System},
+                         IncludeSearchPath{"/builtin/path", 3, IncludeSearchPathType::BuiltIn},
+                         IncludeSearchPath{"/framework/path", 1, IncludeSearchPathType::System}},
+                        {IncludeSearchPath{"/to/path1", 1, IncludeSearchPathType::User},
+                         IncludeSearchPath{"/to/path2", 2, IncludeSearchPathType::User}}};
     PchTask projectTask2{"ProjectPart2",
                          {11, 12},
                          {{"SE", "4", 4}, {"WU", "5", 5}},
-                         {{"ER", 2}, {"SAN", 3}}};
+                         {{"ER", 2}, {"SAN", 3}},
+                         {"--yi"},
+                         {IncludeSearchPath{"/system/path", 2, IncludeSearchPathType::System},
+                          IncludeSearchPath{"/builtin/path", 3, IncludeSearchPathType::BuiltIn},
+                          IncludeSearchPath{"/framework/path", 1, IncludeSearchPathType::System}},
+                         {IncludeSearchPath{"/to/path1", 1, IncludeSearchPathType::User},
+                          IncludeSearchPath{"/to/path2", 2, IncludeSearchPathType::User}}};
+    Utils::SmallStringVector toolChainArguments = {"toolChainArguments"};
 };
 
 TEST_F(PchTasksMerger, AddProjectTasks)
@@ -70,8 +100,8 @@ TEST_F(PchTasksMerger, AddProjectTasks)
     EXPECT_CALL(mockPchTaskQueue, processEntries());
 
     merger.mergeTasks(
-        {{clone(systemTask1), clone(projectTask1)}, {clone(systemTask1), clone(projectTask2)}});
-
+        {{clone(systemTask1), clone(projectTask1)}, {clone(systemTask1), clone(projectTask2)}},
+        std::move(toolChainArguments));
 }
 
 TEST_F(PchTasksMerger, AddSystemTasks)
@@ -82,5 +112,14 @@ TEST_F(PchTasksMerger, AddSystemTasks)
     EXPECT_CALL(mockPchTaskQueue, processEntries());
 
     merger.mergeTasks(
-        {{clone(systemTask1), clone(projectTask1)}, {clone(systemTask2), clone(projectTask2)}});
+        {{clone(systemTask1), clone(projectTask1)}, {clone(systemTask2), clone(projectTask2)}},
+        std::move(toolChainArguments));
+}
+
+TEST_F(PchTasksMerger, RemoveTasks)
+{
+    EXPECT_CALL(mockPchTaskQueue, removePchTasks(ElementsAre("project1", "project2")));
+
+    merger.removePchTasks({"project1", "project2"});
+}
 }
diff --git a/tests/unit/unittest/precompiledheaderstorage-test.cpp b/tests/unit/unittest/precompiledheaderstorage-test.cpp
index 61fdfb5a88..fb65aa7c80 100644
--- a/tests/unit/unittest/precompiledheaderstorage-test.cpp
+++ b/tests/unit/unittest/precompiledheaderstorage-test.cpp
@@ -119,7 +119,7 @@ TEST_F(PrecompiledHeaderStorage, DeleteProjectPrecompiledHeaderStatementIsBusy)
     storage.deleteProjectPrecompiledHeader("project1");
 }
 
-TEST_F(PrecompiledHeaderStorage, InsertSystemPrecompiledHeader)
+TEST_F(PrecompiledHeaderStorage, InsertSystemPrecompiledHeaders)
 {
     InSequence s;
 
@@ -129,12 +129,17 @@ TEST_F(PrecompiledHeaderStorage, InsertSystemPrecompiledHeader)
                 write(TypedEq<Utils::SmallStringView>("project1"),
                       TypedEq<Utils::SmallStringView>("/path/to/pch"),
                       TypedEq<long long>(22)));
+    EXPECT_CALL(insertProjectPartStatement, write(TypedEq<Utils::SmallStringView>("project2")));
+    EXPECT_CALL(insertSystemPrecompiledHeaderStatement,
+                write(TypedEq<Utils::SmallStringView>("project2"),
+                      TypedEq<Utils::SmallStringView>("/path/to/pch"),
+                      TypedEq<long long>(22)));
     EXPECT_CALL(database, commit());
 
-    storage.insertSystemPrecompiledHeader("project1", "/path/to/pch", 22);
+    storage.insertSystemPrecompiledHeaders({"project1", "project2"}, "/path/to/pch", 22);
 }
 
-TEST_F(PrecompiledHeaderStorage, InsertSystemPrecompiledHeaderStatementIsBusy)
+TEST_F(PrecompiledHeaderStorage, InsertSystemPrecompiledHeadersStatementIsBusy)
 {
     InSequence s;
 
@@ -145,32 +150,43 @@ TEST_F(PrecompiledHeaderStorage, InsertSystemPrecompiledHeaderStatementIsBusy)
                 write(TypedEq<Utils::SmallStringView>("project1"),
                       TypedEq<Utils::SmallStringView>("/path/to/pch"),
                       TypedEq<long long>(22)));
+    EXPECT_CALL(insertProjectPartStatement, write(TypedEq<Utils::SmallStringView>("project2")));
+    EXPECT_CALL(insertSystemPrecompiledHeaderStatement,
+                write(TypedEq<Utils::SmallStringView>("project2"),
+                      TypedEq<Utils::SmallStringView>("/path/to/pch"),
+                      TypedEq<long long>(22)));
     EXPECT_CALL(database, commit());
 
-    storage.insertSystemPrecompiledHeader("project1", "/path/to/pch", 22);
+    storage.insertSystemPrecompiledHeaders({"project1", "project2"}, "/path/to/pch", 22);
 }
 
-TEST_F(PrecompiledHeaderStorage, DeleteSystemPrecompiledHeader)
+TEST_F(PrecompiledHeaderStorage, DeleteSystemPrecompiledHeaders)
 {
     InSequence s;
 
     EXPECT_CALL(database, immediateBegin());
-    EXPECT_CALL(deleteSystemPrecompiledHeaderStatement, write(TypedEq<Utils::SmallStringView>("project1")));
+    EXPECT_CALL(deleteSystemPrecompiledHeaderStatement,
+                write(TypedEq<Utils::SmallStringView>("project1")));
+    EXPECT_CALL(deleteSystemPrecompiledHeaderStatement,
+                write(TypedEq<Utils::SmallStringView>("project2")));
     EXPECT_CALL(database, commit());
 
-    storage.deleteSystemPrecompiledHeader("project1");
+    storage.deleteSystemPrecompiledHeaders({"project1", "project2"});
 }
 
-TEST_F(PrecompiledHeaderStorage, DeleteSystemPrecompiledHeaderStatementIsBusy)
+TEST_F(PrecompiledHeaderStorage, DeleteSystemPrecompiledHeadersStatementIsBusy)
 {
     InSequence s;
 
     EXPECT_CALL(database, immediateBegin()).WillOnce(Throw(Sqlite::StatementIsBusy("busy")));
     EXPECT_CALL(database, immediateBegin());
-    EXPECT_CALL(deleteSystemPrecompiledHeaderStatement, write(TypedEq<Utils::SmallStringView>("project1")));
+    EXPECT_CALL(deleteSystemPrecompiledHeaderStatement,
+                write(TypedEq<Utils::SmallStringView>("project1")));
+    EXPECT_CALL(deleteSystemPrecompiledHeaderStatement,
+                write(TypedEq<Utils::SmallStringView>("project2")));
     EXPECT_CALL(database, commit());
 
-    storage.deleteSystemPrecompiledHeader("project1");
+    storage.deleteSystemPrecompiledHeaders({"project1", "project2"});
 }
 
 TEST_F(PrecompiledHeaderStorage, CompilePrecompiledHeaderStatements)
@@ -187,7 +203,7 @@ TEST_F(PrecompiledHeaderStorage, FetchSystemPrecompiledHeaderCalls)
 
     EXPECT_CALL(database, deferredBegin());
     EXPECT_CALL(fetchSystemPrecompiledHeaderPathStatement,
-                valueReturnPathString(TypedEq<Utils::SmallStringView>("project1")));
+                valueReturnFilePath(TypedEq<Utils::SmallStringView>("project1")));
     EXPECT_CALL(database, commit());
 
     storage.fetchSystemPrecompiledHeaderPath("project1");
@@ -196,8 +212,8 @@ TEST_F(PrecompiledHeaderStorage, FetchSystemPrecompiledHeaderCalls)
 TEST_F(PrecompiledHeaderStorage, FetchSystemPrecompiledHeader)
 {
     EXPECT_CALL(fetchSystemPrecompiledHeaderPathStatement,
-                valueReturnPathString(TypedEq<Utils::SmallStringView>("project1")))
-        .WillOnce(Return(Utils::PathString{"/path/to/pch"}));
+                valueReturnFilePath(TypedEq<Utils::SmallStringView>("project1")))
+        .WillOnce(Return(ClangBackEnd::FilePath{"/path/to/pch"}));
 
     auto path = storage.fetchSystemPrecompiledHeaderPath("project1");
 
@@ -207,8 +223,8 @@ TEST_F(PrecompiledHeaderStorage, FetchSystemPrecompiledHeader)
 TEST_F(PrecompiledHeaderStorage, FetchSystemPrecompiledHeaderReturnsEmptyPath)
 {
     EXPECT_CALL(fetchSystemPrecompiledHeaderPathStatement,
-                valueReturnPathString(TypedEq<Utils::SmallStringView>("project1")))
-        .WillOnce(Return(Utils::PathString{}));
+                valueReturnFilePath(TypedEq<Utils::SmallStringView>("project1")))
+        .WillOnce(Return(ClangBackEnd::FilePath{}));
 
     auto path = storage.fetchSystemPrecompiledHeaderPath("project1");
 
@@ -218,8 +234,8 @@ TEST_F(PrecompiledHeaderStorage, FetchSystemPrecompiledHeaderReturnsEmptyPath)
 TEST_F(PrecompiledHeaderStorage, FetchSystemPrecompiledHeaderReturnsNullOptional)
 {
     EXPECT_CALL(fetchSystemPrecompiledHeaderPathStatement,
-                valueReturnPathString(TypedEq<Utils::SmallStringView>("project1")))
-        .WillOnce(Return(Utils::optional<Utils::PathString>{}));
+                valueReturnFilePath(TypedEq<Utils::SmallStringView>("project1")))
+        .WillOnce(Return(Utils::optional<ClangBackEnd::FilePath>{}));
 
     auto path = storage.fetchSystemPrecompiledHeaderPath("project1");
 
diff --git a/tests/unit/unittest/progresscounter-test.cpp b/tests/unit/unittest/progresscounter-test.cpp
index 059bd3bae4..dde6419cc6 100644
--- a/tests/unit/unittest/progresscounter-test.cpp
+++ b/tests/unit/unittest/progresscounter-test.cpp
@@ -56,6 +56,15 @@ TEST_F(ProgressCounter, AddTotal)
     counter.addTotal(7);
 }
 
+TEST_F(ProgressCounter, AddTotalZero)
+{
+    counter.addTotal(5);
+
+    EXPECT_CALL(mockSetProgressCallback, Call(_, _)).Times(0);
+
+    counter.addTotal(0);
+}
+
 TEST_F(ProgressCounter, RemoveTotal)
 {
     counter.addTotal(11);
@@ -66,6 +75,15 @@ TEST_F(ProgressCounter, RemoveTotal)
     counter.removeTotal(7);
 }
 
+TEST_F(ProgressCounter, RemoveTotalZero)
+{
+    counter.addTotal(11);
+
+    EXPECT_CALL(mockSetProgressCallback, Call(_, _)).Times(0);
+
+    counter.removeTotal(0);
+}
+
 TEST_F(ProgressCounter, AddProgress)
 {
     counter.addTotal(11);
@@ -76,6 +94,16 @@ TEST_F(ProgressCounter, AddProgress)
     counter.addProgress(4);
 }
 
+TEST_F(ProgressCounter, AddProgressZero)
+{
+    counter.addTotal(11);
+    counter.addProgress(3);
+
+    EXPECT_CALL(mockSetProgressCallback, Call(_, _)).Times(0);
+
+    counter.addProgress(0);
+}
+
 TEST_F(ProgressCounter, AddTotalAfterFinishingProgress)
 {
     counter.addTotal(11);
diff --git a/tests/unit/unittest/projectpartartefact-test.cpp b/tests/unit/unittest/projectpartartefact-test.cpp
index f7d3a031a4..b38f15333e 100644
--- a/tests/unit/unittest/projectpartartefact-test.cpp
+++ b/tests/unit/unittest/projectpartartefact-test.cpp
@@ -30,30 +30,32 @@
 namespace {
 
 using ClangBackEnd::CompilerMacro;
+using ClangBackEnd::IncludeSearchPath;
+using ClangBackEnd::IncludeSearchPathType;
 
 TEST(ProjectPartArtefact, CompilerArguments)
 {
-    ClangBackEnd::ProjectPartArtefact artefact{"[\"-DFoo\",\"-DBar\"]", "", "", 1};
+    ClangBackEnd::ProjectPartArtefact artefact{"[\"-DFoo\",\"-DBar\"]", "", "", "", 1};
 
     ASSERT_THAT(artefact.compilerArguments, ElementsAre(Eq("-DFoo"), Eq("-DBar")));
 }
 
 TEST(ProjectPartArtefact, EmptyCompilerArguments)
 {
-    ClangBackEnd::ProjectPartArtefact artefact{"", "",  "", 1};
+    ClangBackEnd::ProjectPartArtefact artefact{"", "",  "", "", 1};
 
     ASSERT_THAT(artefact.compilerArguments, IsEmpty());
 }
 
 TEST(ProjectPartArtefact, CompilerArgumentsParseError)
 {
-    ASSERT_THROW(ClangBackEnd::ProjectPartArtefact("\"-DFoo\",\"-DBar\"]", "",  "", 1),
+    ASSERT_THROW(ClangBackEnd::ProjectPartArtefact("\"-DFoo\",\"-DBar\"]", "", "", "", 1),
                  ClangBackEnd::ProjectPartArtefactParseError);
 }
 
 TEST(ProjectPartArtefact, CompilerMacros)
 {
-    ClangBackEnd::ProjectPartArtefact artefact{"", "{\"Foo\":\"1\",\"Bar\":\"42\"}",  "", 1};
+    ClangBackEnd::ProjectPartArtefact artefact{"", R"([["Foo","1",1], ["Bar","42",2]])", "", "", 1};
 
     ASSERT_THAT(artefact.compilerMacros,
                 UnorderedElementsAre(Eq(CompilerMacro{"Foo", "1", 1}), Eq(CompilerMacro{"Bar", "42", 2})));
@@ -61,35 +63,65 @@ TEST(ProjectPartArtefact, CompilerMacros)
 
 TEST(ProjectPartArtefact, EmptyCompilerMacros)
 {
-    ClangBackEnd::ProjectPartArtefact artefact{"", "",  "", 1};
+    ClangBackEnd::ProjectPartArtefact artefact{"", "",  "", "", 1};
 
     ASSERT_THAT(artefact.compilerMacros, IsEmpty());
 }
 
 TEST(ProjectPartArtefact, CompilerMacrosParseError)
 {
-    ASSERT_THROW(ClangBackEnd::ProjectPartArtefact("", "\"Foo\":\"1\",\"Bar\":\"42\"}", "", 1),
+    ASSERT_THROW(ClangBackEnd::ProjectPartArtefact("", R"([["Foo":"1", 1], ["Bar", "42", 2]])", "", "", 1),
                  ClangBackEnd::ProjectPartArtefactParseError);
 }
 
-TEST(ProjectPartArtefact, IncludeSearchPaths)
+TEST(ProjectPartArtefact, SystemIncludeSearchPaths)
 {
-    ClangBackEnd::ProjectPartArtefact artefact{"", "",  "[\"/includes\",\"/other/includes\"]", 1};
+    ClangBackEnd::ProjectPartArtefact artefact{
+        "", "", R"([["/includes", 1, 2], ["/other/includes", 2, 3]])", "", 1};
 
-    ASSERT_THAT(artefact.includeSearchPaths, ElementsAre(Eq("/includes"), Eq("/other/includes")));
+    ASSERT_THAT(
+        artefact.systemIncludeSearchPaths,
+        ElementsAre(Eq(IncludeSearchPath("/includes", 1, IncludeSearchPathType::BuiltIn)),
+                    Eq(IncludeSearchPath("/other/includes", 2, IncludeSearchPathType::System))));
 }
 
-TEST(ProjectPartArtefact, EmptyIncludeSearchPaths)
+TEST(ProjectPartArtefact, EmptySystemIncludeSearchPaths)
 {
-    ClangBackEnd::ProjectPartArtefact artefact{"", "",  "", 1};
+    ClangBackEnd::ProjectPartArtefact artefact{"", "", "", "", 1};
 
-    ASSERT_THAT(artefact.includeSearchPaths, IsEmpty());
+    ASSERT_THAT(artefact.systemIncludeSearchPaths, IsEmpty());
 }
 
-TEST(ProjectPartArtefact, IncludeSearchPathsParseError)
+TEST(ProjectPartArtefact, ProjectIncludeSearchPaths)
 {
-    ASSERT_THROW(ClangBackEnd::ProjectPartArtefact("", "",  "\"/includes\",\"/other/includes\"]", 1),
-                 ClangBackEnd::ProjectPartArtefactParseError);
+    ClangBackEnd::ProjectPartArtefact artefact{
+        "", "", R"([["/project/includes", 1, 1], ["/other/project/includes", 2, 1]])", "", 1};
+
+    ASSERT_THAT(
+        artefact.systemIncludeSearchPaths,
+        ElementsAre(
+            Eq(IncludeSearchPath("/project/includes", 1, IncludeSearchPathType::User)),
+            Eq(IncludeSearchPath("/other/project/includes", 2, IncludeSearchPathType::User))));
+}
+
+TEST(ProjectPartArtefact, EmptyProjectIncludeSearchPaths)
+{
+    ClangBackEnd::ProjectPartArtefact artefact{"", "",  "", "", 1};
+
+    ASSERT_THAT(artefact.projectIncludeSearchPaths, IsEmpty());
 }
 
+TEST(ProjectPartArtefact, IncludeSystemSearchPathsParseError)
+{
+    ASSERT_THROW(
+        ClangBackEnd::ProjectPartArtefact("", "", R"(["/includes", 1, 3], ["/other/includes", 2, 2]])", "", 1),
+        ClangBackEnd::ProjectPartArtefactParseError);
+}
+
+TEST(ProjectPartArtefact, IncludeProjectSearchPathsParseError)
+{
+    ASSERT_THROW(
+        ClangBackEnd::ProjectPartArtefact("", "", R"(["/project/includes", 1, 1], ["/other/project/includes", 2, 1]])", "", 1),
+        ClangBackEnd::ProjectPartArtefactParseError);
+}
 }
diff --git a/tests/unit/unittest/projectpartqueue-test.cpp b/tests/unit/unittest/projectpartqueue-test.cpp
deleted file mode 100644
index 65318a3e91..0000000000
--- a/tests/unit/unittest/projectpartqueue-test.cpp
+++ /dev/null
@@ -1,183 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2018 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of Qt Creator.
-**
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 3 as published by the Free Software
-** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-3.0.html.
-**
-****************************************************************************/
-
-#include "googletest.h"
-
-#include "mocktaskscheduler.h"
-#include "mockpchcreator.h"
-#include "mockprecompiledheaderstorage.h"
-#include "mocksqlitetransactionbackend.h"
-
-#include <projectpartqueue.h>
-#include <progresscounter.h>
-
-namespace {
-
-using ClangBackEnd::SlotUsage;
-using ClangBackEnd::V2::ProjectPartContainer;
-
-class ProjectPartQueue : public testing::Test
-{
-protected:
-    NiceMock<MockTaskScheduler<ClangBackEnd::ProjectPartQueue::Task>> mockTaskScheduler;
-    MockPrecompiledHeaderStorage mockPrecompiledHeaderStorage;
-    MockSqliteTransactionBackend mockSqliteTransactionBackend;
-    NiceMock<MockFunction<void(int, int)>> mockSetProgressCallback;
-    ClangBackEnd::ProgressCounter progressCounter{mockSetProgressCallback.AsStdFunction()};
-    ClangBackEnd::ProjectPartQueue queue{mockTaskScheduler, mockPrecompiledHeaderStorage, mockSqliteTransactionBackend, progressCounter};
-    ClangBackEnd::V2::ProjectPartContainer projectPart1{"ProjectPart1",
-                                                        {"--yi"},
-                                                        {{"YI","1", 1}},
-                                                        {"/yi"},
-                                                        {1},
-                                                        {2}};
-    ClangBackEnd::V2::ProjectPartContainer projectPart2{"ProjectPart2",
-                                                        {"--er"},
-                                                        {{"ER","2", 1}},
-                                                        {"/bar"},
-                                                        {1},
-                                                        {2}};
-    ClangBackEnd::V2::ProjectPartContainer projectPart2b{"ProjectPart2",
-                                                        {"--liang"},
-                                                        {{"LIANG","3", 1}},
-                                                        {"/liang"},
-                                                        {3},
-                                                        {2, 4}};
-    ClangBackEnd::V2::ProjectPartContainer projectPart3{"ProjectPart3",
-                                                        {"--san"},
-                                                        {{"SAN","2", 1}},
-                                                        {"/SAN"},
-                                                        {1},
-                                                        {2}};
-};
-
-TEST_F(ProjectPartQueue, AddProjectPart)
-{
-    queue.addProjectParts({projectPart1});
-
-    queue.addProjectParts({projectPart2});
-
-    ASSERT_THAT(queue.projectParts(), ElementsAre(projectPart1, projectPart2));
-}
-
-TEST_F(ProjectPartQueue, AddProjectPartCallsProcessEntries)
-{
-    InSequence s;
-
-    EXPECT_CALL(mockTaskScheduler, slotUsage()).WillRepeatedly(Return(SlotUsage{2, 0}));
-    EXPECT_CALL(mockTaskScheduler, addTasks(SizeIs(2)));
-
-    queue.addProjectParts({projectPart1, projectPart2});
-}
-
-TEST_F(ProjectPartQueue, AddProjectPartCallsProgressCounter)
-{
-    queue.addProjectParts({projectPart1, projectPart2});
-
-    EXPECT_CALL(mockSetProgressCallback, Call(0, 3));
-
-    queue.addProjectParts({projectPart2b, projectPart3});
-}
-
-TEST_F(ProjectPartQueue, IgnoreIdenticalProjectPart)
-{
-    queue.addProjectParts({projectPart1, projectPart2});
-
-    queue.addProjectParts({projectPart1, projectPart2});
-
-    ASSERT_THAT(queue.projectParts(), ElementsAre(projectPart1, projectPart2));
-}
-
-TEST_F(ProjectPartQueue, ReplaceProjectPartWithSameId)
-{
-    queue.addProjectParts({projectPart1, projectPart2});
-
-    queue.addProjectParts({projectPart1, projectPart2b, projectPart3});
-
-    ASSERT_THAT(queue.projectParts(), ElementsAre(projectPart1, projectPart2b, projectPart3));
-}
-
-TEST_F(ProjectPartQueue, RemoveProjectPart)
-{
-    queue.addProjectParts({projectPart1, projectPart2, projectPart3});
-
-    queue.removeProjectParts({projectPart2.projectPartId});
-
-    ASSERT_THAT(queue.projectParts(), ElementsAre(projectPart1, projectPart3));
-}
-
-TEST_F(ProjectPartQueue, RemoveProjectPartCallsProgressCounter)
-{
-    queue.addProjectParts({projectPart1, projectPart2, projectPart3});
-
-    EXPECT_CALL(mockSetProgressCallback, Call(0, 2));
-
-    queue.removeProjectParts({projectPart2.projectPartId});
-}
-
-TEST_F(ProjectPartQueue, CreateTasksSizeEqualsInputSize)
-{
-    auto tasks = queue.createPchTasks({projectPart1, projectPart2});
-
-    ASSERT_THAT(tasks, SizeIs(2));
-}
-
-TEST_F(ProjectPartQueue, CreateTaskFromProjectPart)
-{
-    InSequence s;
-    MockPchCreator mockPchCreator;
-    ClangBackEnd::ProjectPartPch projectPartPch{"project1", "/path/to/pch", 99};
-    auto tasks = queue.createPchTasks({projectPart1});
-
-    EXPECT_CALL(mockPchCreator, generatePchDeprecated(Eq(projectPart1)));
-    EXPECT_CALL(mockPchCreator, projectPartPch()).WillOnce(ReturnRef(projectPartPch));
-    EXPECT_CALL(mockSqliteTransactionBackend, lock());
-    EXPECT_CALL(mockSqliteTransactionBackend, immediateBegin());
-    EXPECT_CALL(mockPrecompiledHeaderStorage, insertProjectPrecompiledHeader(Eq("project1"), Eq("/path/to/pch"), 99));
-    EXPECT_CALL(mockSqliteTransactionBackend, commit());
-    EXPECT_CALL(mockSqliteTransactionBackend, unlock());
-
-    tasks.front()(mockPchCreator);
-}
-
-TEST_F(ProjectPartQueue, DeletePchEntryInDatabaseIfNoPchIsGenerated)
-{
-    InSequence s;
-    MockPchCreator mockPchCreator;
-    ClangBackEnd::ProjectPartPch projectPartPch{"project1", "", 0};
-    auto tasks = queue.createPchTasks({projectPart1});
-
-    EXPECT_CALL(mockPchCreator, generatePchDeprecated(Eq(projectPart1)));
-    EXPECT_CALL(mockPchCreator, projectPartPch()).WillOnce(ReturnRef(projectPartPch));
-    EXPECT_CALL(mockSqliteTransactionBackend, lock());
-    EXPECT_CALL(mockSqliteTransactionBackend, immediateBegin());
-    EXPECT_CALL(mockPrecompiledHeaderStorage, deleteProjectPrecompiledHeader(Eq("project1")));
-    EXPECT_CALL(mockSqliteTransactionBackend, commit());
-    EXPECT_CALL(mockSqliteTransactionBackend, unlock());
-
-    tasks.front()(mockPchCreator);
-}
-
-}
diff --git a/tests/unit/unittest/projectparts-test.cpp b/tests/unit/unittest/projectparts-test.cpp
index 123a43d28f..87ab509206 100644
--- a/tests/unit/unittest/projectparts-test.cpp
+++ b/tests/unit/unittest/projectparts-test.cpp
@@ -27,7 +27,7 @@
 
 #include <projectparts.h>
 
-#include <projectpartcontainerv2.h>
+#include <projectpartcontainer.h>
 
 namespace {
 
@@ -35,7 +35,7 @@ using testing::ElementsAre;
 using testing::UnorderedElementsAre;
 using testing::IsEmpty;
 
-using ClangBackEnd::V2::ProjectPartContainer;
+using ClangBackEnd::ProjectPartContainer;
 using ClangBackEnd::FilePathId;
 
 class ProjectParts : public testing::Test
@@ -47,24 +47,39 @@ protected:
     FilePathId firstSource{11};
     FilePathId secondSource{12};
     FilePathId thirdSource{13};
-    ProjectPartContainer projectPartContainer1{"id",
-                                               {"-DUNIX", "-O2"},
-                                               {{"DEFINE", "1", 1}},
-                                               {"/includes"},
-                                               {firstHeader, secondHeader},
-                                               {firstSource, secondSource}};
-    ProjectPartContainer updatedProjectPartContainer1{"id",
-                                                      {"-DUNIX", "-O2"},
-                                                      {{"DEFINE", "1", 1}},
-                                                      {"/includes"},
-                                                      {firstHeader, secondHeader},
-                                                      {firstSource, secondSource, thirdSource}};
-    ProjectPartContainer projectPartContainer2{"id2",
-                                              {"-DUNIX", "-O2"},
-                                              {{"DEFINE", "1", 1}},
-                                              {"/includes"},
-                                              {firstHeader, secondHeader},
-                                              {firstSource, secondSource}};
+    ProjectPartContainer projectPartContainer1{
+        "id",
+        {"-DUNIX", "-O2"},
+        {{"DEFINE", "1", 1}},
+        {{"/includes", 1, ClangBackEnd::IncludeSearchPathType::BuiltIn}},
+        {{"/project/includes", 1, ClangBackEnd::IncludeSearchPathType::User}},
+        {firstHeader, secondHeader},
+        {firstSource, secondSource},
+        Utils::Language::C,
+        Utils::LanguageVersion::C11,
+        Utils::LanguageExtension::All};
+    ProjectPartContainer updatedProjectPartContainer1{
+        "id",
+        {"-DUNIX", "-O2"},
+        {{"DEFINE", "1", 1}},
+        {{"/includes", 1, ClangBackEnd::IncludeSearchPathType::BuiltIn}},
+        {{"/project/includes", 1, ClangBackEnd::IncludeSearchPathType::User}},
+        {firstHeader, secondHeader},
+        {firstSource, secondSource, thirdSource},
+        Utils::Language::C,
+        Utils::LanguageVersion::C11,
+        Utils::LanguageExtension::All};
+    ProjectPartContainer projectPartContainer2{
+        "id2",
+        {"-DUNIX", "-O2"},
+        {{"DEFINE", "1", 1}},
+        {{"/includes", 1, ClangBackEnd::IncludeSearchPathType::BuiltIn}},
+        {{"/project/includes", 1, ClangBackEnd::IncludeSearchPathType::User}},
+        {firstHeader, secondHeader},
+        {firstSource, secondSource},
+        Utils::Language::C,
+        Utils::LanguageVersion::C11,
+        Utils::LanguageExtension::All};
 };
 
 TEST_F(ProjectParts, GetNoProjectPartsForAddingEmptyProjectParts)
diff --git a/tests/unit/unittest/projectupdater-test.cpp b/tests/unit/unittest/projectupdater-test.cpp
index 88f438b82c..293a4ef15e 100644
--- a/tests/unit/unittest/projectupdater-test.cpp
+++ b/tests/unit/unittest/projectupdater-test.cpp
@@ -43,6 +43,7 @@
 #include <updategeneratedfilesmessage.h>
 #include <updateprojectpartsmessage.h>
 
+#include <projectexplorer/projectexplorerconstants.h>
 #include <cpptools/compileroptionsbuilder.h>
 #include <cpptools/projectpart.h>
 
@@ -57,8 +58,10 @@ using testing::NiceMock;
 using testing::AnyNumber;
 
 using ClangBackEnd::CompilerMacro;
+using ClangBackEnd::IncludeSearchPath;
+using ClangBackEnd::IncludeSearchPathType;
 using ClangBackEnd::V2::FileContainer;
-using ClangBackEnd::V2::ProjectPartContainer;
+using ClangBackEnd::ProjectPartContainer;
 using CppTools::CompilerOptionsBuilder;
 using ProjectExplorer::HeaderPath;
 
@@ -96,23 +99,31 @@ protected:
         projectPartId2 = projectPart2.id();
 
 
-        Utils::SmallStringVector arguments{ClangPchManager::ProjectUpdater::compilerArguments(
+        Utils::SmallStringVector arguments{ClangPchManager::ProjectUpdater::toolChainArguments(
                         &projectPart)};
-        Utils::SmallStringVector arguments2{ClangPchManager::ProjectUpdater::compilerArguments(
+        Utils::SmallStringVector arguments2{ClangPchManager::ProjectUpdater::toolChainArguments(
                         &projectPart2)};
 
         expectedContainer = {projectPartId.clone(),
                              arguments.clone(),
                              Utils::clone(compilerMacros),
+                             {{CLANG_RESOURCE_DIR, 1, ClangBackEnd::IncludeSearchPathType::BuiltIn}},
                              {},
                              {filePathId(headerPaths[1])},
-                             {filePathIds(sourcePaths)}};
+                             {filePathIds(sourcePaths)},
+                             Utils::Language::Cxx,
+                             Utils::LanguageVersion::LatestCxx,
+                             Utils::LanguageExtension::None};
         expectedContainer2 = {projectPartId2.clone(),
                               arguments2.clone(),
                               Utils::clone(compilerMacros),
+                              {{CLANG_RESOURCE_DIR, 1, ClangBackEnd::IncludeSearchPathType::BuiltIn}},
                               {},
                               {filePathId(headerPaths[1])},
-                              {filePathIds(sourcePaths)}};
+                              {filePathIds(sourcePaths)},
+                              Utils::Language::Cxx,
+                              Utils::LanguageVersion::LatestCxx,
+                              Utils::LanguageExtension::None};
     }
 
 protected:
@@ -145,12 +156,13 @@ protected:
 TEST_F(ProjectUpdater, CallUpdateProjectParts)
 {
     std::vector<CppTools::ProjectPart*> projectParts = {&projectPart2, &projectPart};
-    ClangBackEnd::UpdateProjectPartsMessage message{{expectedContainer.clone(), expectedContainer2.clone()}};
+    ClangBackEnd::UpdateProjectPartsMessage message{
+        {expectedContainer.clone(), expectedContainer2.clone()}, {"toolChainArgument"}};
     updater.updateGeneratedFiles({generatedFile});
 
     EXPECT_CALL(mockPchManagerServer, updateProjectParts(message));
 
-    updater.updateProjectParts(projectParts);
+    updater.updateProjectParts(projectParts, {"toolChainArgument"});
 }
 
 TEST_F(ProjectUpdater, CallUpdateGeneratedFilesWithSortedEntries)
@@ -253,14 +265,109 @@ TEST_F(ProjectUpdater, CreateSortedCompilerMacros)
 
 TEST_F(ProjectUpdater, CreateSortedIncludeSearchPaths)
 {
+    CppTools::ProjectPart projectPart;
     ProjectExplorer::HeaderPath includePath{"/to/path1", ProjectExplorer::HeaderPathType::User};
     ProjectExplorer::HeaderPath includePath2{"/to/path2", ProjectExplorer::HeaderPathType::User};
     ProjectExplorer::HeaderPath invalidPath;
-    ProjectExplorer::HeaderPath frameworkPath{"/framework/path", ProjectExplorer::HeaderPathType::Framework};
+    ProjectExplorer::HeaderPath frameworkPath{"/framework/path",
+                                              ProjectExplorer::HeaderPathType::Framework};
+    ProjectExplorer::HeaderPath builtInPath{"/builtin/path", ProjectExplorer::HeaderPathType::BuiltIn};
+    ProjectExplorer::HeaderPath systemPath{"/system/path", ProjectExplorer::HeaderPathType::System};
+    projectPart.headerPaths = {
+        systemPath, builtInPath, frameworkPath, includePath2, includePath, invalidPath};
+
+    auto paths = updater.createIncludeSearchPaths(projectPart);
+
+    ASSERT_THAT(paths.system,
+                ElementsAre(Eq(IncludeSearchPath{systemPath.path, 1, IncludeSearchPathType::System}),
+                            Eq(IncludeSearchPath{builtInPath.path, 4, IncludeSearchPathType::BuiltIn}),
+                            Eq(IncludeSearchPath{frameworkPath.path, 2, IncludeSearchPathType::Framework}),
+                            Eq(IncludeSearchPath{CLANG_RESOURCE_DIR,
+                                                 3,
+                                                 ClangBackEnd::IncludeSearchPathType::BuiltIn})));
+    ASSERT_THAT(paths.project,
+                ElementsAre(Eq(IncludeSearchPath{includePath.path, 2, IncludeSearchPathType::User}),
+                            Eq(IncludeSearchPath{includePath2.path, 1, IncludeSearchPathType::User})));
+}
+
+TEST_F(ProjectUpdater, ToolChainArguments)
+{
+    projectPart.toolChainTargetTriple = "target";
+    projectPart.extraCodeModelFlags.push_back("extraflags");
+    projectPart.compilerFlags.push_back("-fPIC");
+    projectPart.projectConfigFile = "config.h";
 
-    auto paths = updater.createIncludeSearchPaths({frameworkPath, includePath2, includePath, invalidPath});
+    auto arguments = updater.toolChainArguments(&projectPart);
 
-    ASSERT_THAT(paths, ElementsAre(includePath.path, includePath2.path, frameworkPath.path));
+    ASSERT_THAT(arguments,
+                ElementsAre("-m32", "-fPIC", "--target=target", "extraflags", "-include", "config.h"));
+}
+
+TEST_F(ProjectUpdater, ToolChainArgumentsMSVC)
+{
+    projectPart.toolChainTargetTriple = "target";
+    projectPart.extraCodeModelFlags.push_back("extraflags");
+    projectPart.toolchainType = ProjectExplorer::Constants::MSVC_TOOLCHAIN_TYPEID;
+    projectPart.isMsvc2015Toolchain = true;
+
+    auto arguments = updater.toolChainArguments(&projectPart);
+
+    ASSERT_THAT(arguments,
+                ElementsAre("-m32",
+                            "--target=target",
+                            "extraflags",
+                            "-U__clang__",
+                            "-U__clang_major__",
+                            "-U__clang_minor__",
+                            "-U__clang_patchlevel__",
+                            "-U__clang_version__",
+                            "-U__cpp_aggregate_bases",
+                            "-U__cpp_aggregate_nsdmi",
+                            "-U__cpp_alias_templates",
+                            "-U__cpp_aligned_new",
+                            "-U__cpp_attributes",
+                            "-U__cpp_binary_literals",
+                            "-U__cpp_capture_star_this",
+                            "-U__cpp_constexpr",
+                            "-U__cpp_decltype",
+                            "-U__cpp_decltype_auto",
+                            "-U__cpp_deduction_guides",
+                            "-U__cpp_delegating_constructors",
+                            "-U__cpp_digit_separators",
+                            "-U__cpp_enumerator_attributes",
+                            "-U__cpp_exceptions",
+                            "-U__cpp_fold_expressions",
+                            "-U__cpp_generic_lambdas",
+                            "-U__cpp_guaranteed_copy_elision",
+                            "-U__cpp_hex_float",
+                            "-U__cpp_if_constexpr",
+                            "-U__cpp_inheriting_constructors",
+                            "-U__cpp_init_captures",
+                            "-U__cpp_initializer_lists",
+                            "-U__cpp_inline_variables",
+                            "-U__cpp_lambdas",
+                            "-U__cpp_namespace_attributes",
+                            "-U__cpp_nested_namespace_definitions",
+                            "-U__cpp_noexcept_function_type",
+                            "-U__cpp_nontype_template_args",
+                            "-U__cpp_nontype_template_parameter_auto",
+                            "-U__cpp_nsdmi",
+                            "-U__cpp_range_based_for",
+                            "-U__cpp_raw_strings",
+                            "-U__cpp_ref_qualifiers",
+                            "-U__cpp_return_type_deduction",
+                            "-U__cpp_rtti",
+                            "-U__cpp_rvalue_references",
+                            "-U__cpp_static_assert",
+                            "-U__cpp_structured_bindings",
+                            "-U__cpp_template_auto",
+                            "-U__cpp_threadsafe_static_init",
+                            "-U__cpp_unicode_characters",
+                            "-U__cpp_unicode_literals",
+                            "-U__cpp_user_defined_literals",
+                            "-U__cpp_variable_templates",
+                            "-U__cpp_variadic_templates",
+                            "-U__cpp_variadic_using"));
 }
 
 }
diff --git a/tests/unit/unittest/refactoringclientserverinprocess-test.cpp b/tests/unit/unittest/refactoringclientserverinprocess-test.cpp
index 55af349bbb..659dcf735f 100644
--- a/tests/unit/unittest/refactoringclientserverinprocess-test.cpp
+++ b/tests/unit/unittest/refactoringclientserverinprocess-test.cpp
@@ -52,7 +52,7 @@ using ClangBackEnd::RemoveProjectPartsMessage;
 using ClangBackEnd::UpdateProjectPartsMessage;
 using ClangBackEnd::UpdateGeneratedFilesMessage;
 using ClangBackEnd::V2::FileContainer;
-using ClangBackEnd::V2::ProjectPartContainer;
+using ClangBackEnd::ProjectPartContainer;
 
 class RefactoringClientServerInProcess : public ::testing::Test
 {
@@ -192,10 +192,17 @@ TEST_F(RefactoringClientServerInProcess, SendUpdateProjectPartsMessage)
     ProjectPartContainer projectPart2{"projectPartId",
                                       {"-x", "c++-header", "-Wno-pragma-once-outside-header"},
                                       {{"DEFINE", "1", 1}},
-                                      {"/includes"},
+                                      {IncludeSearchPath{"/system/path", 2, IncludeSearchPathType::System},
+                                       IncludeSearchPath{"/builtin/path", 3, IncludeSearchPathType::BuiltIn},
+                                       IncludeSearchPath{"/framework/path", 1, IncludeSearchPathType::System}},
+                                      {IncludeSearchPath{"/to/path1", 1, IncludeSearchPathType::User},
+                                       IncludeSearchPath{"/to/path2", 2, IncludeSearchPathType::User}},
                                       {{1, 1}},
-                                      {{1, 2}}};
-    UpdateProjectPartsMessage message{{projectPart2}};
+                                      {{1, 2}},
+                                      Utils::Language::C,
+                                      Utils::LanguageVersion::C11,
+                                      Utils::LanguageExtension::All};
+    UpdateProjectPartsMessage message{{projectPart2}, {"toolChainArgument"}};
 
     EXPECT_CALL(mockRefactoringServer, updateProjectParts(message));
 
diff --git a/tests/unit/unittest/refactoringdatabaseinitializer-test.cpp b/tests/unit/unittest/refactoringdatabaseinitializer-test.cpp
index 555d742a60..cfae1d80f0 100644
--- a/tests/unit/unittest/refactoringdatabaseinitializer-test.cpp
+++ b/tests/unit/unittest/refactoringdatabaseinitializer-test.cpp
@@ -88,7 +88,7 @@ TEST_F(RefactoringDatabaseInitializer, AddProjectPartsTable)
 {
     InSequence s;
 
-    EXPECT_CALL(mockDatabase, execute(Eq("CREATE TABLE IF NOT EXISTS projectParts(projectPartId INTEGER PRIMARY KEY, projectPartName TEXT, compilerArguments TEXT, compilerMacros TEXT, includeSearchPaths TEXT)")));
+    EXPECT_CALL(mockDatabase, execute(Eq("CREATE TABLE IF NOT EXISTS projectParts(projectPartId INTEGER PRIMARY KEY, projectPartName TEXT, compilerArguments TEXT, compilerMacros TEXT, systemIncludeSearchPaths TEXT, projectIncludeSearchPaths TEXT)")));
     EXPECT_CALL(mockDatabase, execute(Eq("CREATE UNIQUE INDEX IF NOT EXISTS index_projectParts_projectPartName ON projectParts(projectPartName)")));
 
     initializer.createProjectPartsTable();
@@ -160,7 +160,7 @@ TEST_F(RefactoringDatabaseInitializer, CreateInTheContructor)
     EXPECT_CALL(mockDatabase, execute(Eq("CREATE UNIQUE INDEX IF NOT EXISTS index_sources_directoryId_sourceName ON sources(directoryId, sourceName)")));
     EXPECT_CALL(mockDatabase, execute(Eq("CREATE TABLE IF NOT EXISTS directories(directoryId INTEGER PRIMARY KEY, directoryPath TEXT)")));
     EXPECT_CALL(mockDatabase, execute(Eq("CREATE UNIQUE INDEX IF NOT EXISTS index_directories_directoryPath ON directories(directoryPath)")));
-    EXPECT_CALL(mockDatabase, execute(Eq("CREATE TABLE IF NOT EXISTS projectParts(projectPartId INTEGER PRIMARY KEY, projectPartName TEXT, compilerArguments TEXT, compilerMacros TEXT, includeSearchPaths TEXT)")));
+    EXPECT_CALL(mockDatabase, execute(Eq("CREATE TABLE IF NOT EXISTS projectParts(projectPartId INTEGER PRIMARY KEY, projectPartName TEXT, compilerArguments TEXT, compilerMacros TEXT, systemIncludeSearchPaths TEXT, projectIncludeSearchPaths TEXT)")));
     EXPECT_CALL(mockDatabase, execute(Eq("CREATE UNIQUE INDEX IF NOT EXISTS index_projectParts_projectPartName ON projectParts(projectPartName)")));
     EXPECT_CALL(mockDatabase, execute(Eq("CREATE TABLE IF NOT EXISTS projectPartsSources(projectPartId INTEGER, sourceId INTEGER, sourceType INTEGER)")));
     EXPECT_CALL(mockDatabase, execute(Eq("CREATE UNIQUE INDEX IF NOT EXISTS index_projectPartsSources_sourceId_projectPartId ON projectPartsSources(sourceId, projectPartId)")));
diff --git a/tests/unit/unittest/refactoringprojectupdater-test.cpp b/tests/unit/unittest/refactoringprojectupdater-test.cpp
index 9c878697a4..ceb6d4b15b 100644
--- a/tests/unit/unittest/refactoringprojectupdater-test.cpp
+++ b/tests/unit/unittest/refactoringprojectupdater-test.cpp
@@ -52,7 +52,7 @@ MATCHER_P(IsProjectPartContainer, projectPartId,
           std::string(negation ? "hasn't" : "has")
           + " name " + std::string(projectPartId))
 {
-    const ClangBackEnd::V2::ProjectPartContainer &container = arg;
+    const ClangBackEnd::ProjectPartContainer &container = arg;
 
     return  container.projectPartId == projectPartId;
 }
diff --git a/tests/unit/unittest/refactoringserver-test.cpp b/tests/unit/unittest/refactoringserver-test.cpp
index 42fff8dfd5..b8b97437e4 100644
--- a/tests/unit/unittest/refactoringserver-test.cpp
+++ b/tests/unit/unittest/refactoringserver-test.cpp
@@ -54,18 +54,20 @@ using testing::Property;
 using testing::_;
 
 using ClangBackEnd::FilePath;
+using ClangBackEnd::IncludeSearchPaths;
+using ClangBackEnd::IncludeSearchPathType;
 using ClangBackEnd::RequestSourceLocationsForRenamingMessage;
 using ClangBackEnd::RequestSourceRangesAndDiagnosticsForQueryMessage;
 using ClangBackEnd::RequestSourceRangesForQueryMessage;
 using ClangBackEnd::SourceLocationsContainer;
 using ClangBackEnd::SourceLocationsForRenamingMessage;
 using ClangBackEnd::SourceRangesAndDiagnosticsForQueryMessage;
-using ClangBackEnd::SourceRangesForQueryMessage;
 using ClangBackEnd::SourceRangesContainer;
+using ClangBackEnd::SourceRangesForQueryMessage;
 using ClangBackEnd::V2::FileContainer;
 using ClangBackEnd::V2::FileContainers;
-using ClangBackEnd::V2::ProjectPartContainer;
-using ClangBackEnd::V2::ProjectPartContainers;
+using ClangBackEnd::ProjectPartContainer;
+using ClangBackEnd::ProjectPartContainers;
 
 MATCHER_P2(IsSourceLocation, line, column,
            std::string(negation ? "isn't " : "is ")
@@ -325,18 +327,24 @@ TEST_F(RefactoringServer, RemoveGeneratedFilesSetMemberWhichIsUsedForSymbolIndex
 
 TEST_F(RefactoringServer, UpdateProjectPartsCallsSymbolIndexingUpdateProjectParts)
 {
-    ProjectPartContainers projectParts{{{"projectPartId",
-                                        {"-I", TESTDATA_DIR},
-                                        {{"DEFINE", "1", 1}},
-                                        {"/includes"},
-                                        {filePathId("header1.h")},
-                                        {filePathId("main.cpp")}}}};
-
+    ProjectPartContainers projectParts{
+        {{"projectPartId",
+          {"-I", TESTDATA_DIR},
+          {{"DEFINE", "1", 1}},
+          IncludeSearchPaths{{"/includes", 1, IncludeSearchPathType::BuiltIn},
+                             {"/other/includes", 2, IncludeSearchPathType::System}},
+          IncludeSearchPaths{{"/project/includes", 1, IncludeSearchPathType::User},
+                             {"/other/project/includes", 2, IncludeSearchPathType::User}},
+          {filePathId("header1.h")},
+          {filePathId("main.cpp")},
+          Utils::Language::C,
+          Utils::LanguageVersion::C11,
+          Utils::LanguageExtension::All}}};
 
     EXPECT_CALL(mockSymbolIndexing,
                 updateProjectParts(projectParts));
 
-    refactoringServer.updateProjectParts({Utils::clone(projectParts)});
+    refactoringServer.updateProjectParts({Utils::clone(projectParts), {}});
 }
 
 TEST_F(RefactoringServer, SetProgress)
diff --git a/tests/unit/unittest/symbolindexer-test.cpp b/tests/unit/unittest/symbolindexer-test.cpp
index 37dc4071a0..a5ee83b2b8 100644
--- a/tests/unit/unittest/symbolindexer-test.cpp
+++ b/tests/unit/unittest/symbolindexer-test.cpp
@@ -33,7 +33,7 @@
 
 #include <filepathcaching.h>
 #include <filestatuscache.h>
-#include <projectpartcontainerv2.h>
+#include <projectpartcontainer.h>
 #include <refactoringdatabaseinitializer.h>
 #include <processormanager.h>
 #include <symbolindexer.h>
@@ -54,8 +54,8 @@ using ClangBackEnd::FileStatuses;
 using ClangBackEnd::FilePathId;
 using ClangBackEnd::FilePathIds;
 using ClangBackEnd::FilePathView;
-using ClangBackEnd::V2::ProjectPartContainer;
-using ClangBackEnd::V2::ProjectPartContainers;
+using ClangBackEnd::ProjectPartContainer;
+using ClangBackEnd::ProjectPartContainers;
 using ClangBackEnd::V2::FileContainers;
 using ClangBackEnd::SymbolEntries;
 using ClangBackEnd::SymbolEntry;
@@ -164,24 +164,43 @@ protected:
     ClangBackEnd::FilePathId header1PathId{filePathId(TESTDATA_DIR "/symbolindexer_header2.h")};
     PathString generatedFileName = "BuildDependencyCollector_generated_file.h";
     ClangBackEnd::FilePathId generatedFilePathId21;
+    ClangBackEnd::IncludeSearchPaths systemIncludeSearchPaths{
+        {"/includes", 1, ClangBackEnd::IncludeSearchPathType::BuiltIn},
+        {TESTDATA_DIR, 2, ClangBackEnd::IncludeSearchPathType::System},
+        {"/other/includes", 3, ClangBackEnd::IncludeSearchPathType::System}};
+    ClangBackEnd::IncludeSearchPaths projectIncludeSearchPaths{
+        {"/project/includes", 1, ClangBackEnd::IncludeSearchPathType::User},
+        {"/other/project/includes", 2, ClangBackEnd::IncludeSearchPathType::User}};
     ProjectPartContainer projectPart1{"project1",
-                                      {"-I", TESTDATA_DIR, "-Wno-pragma-once-outside-header"},
+                                      {"-Wno-pragma-once-outside-header"},
                                       {{"BAR", "1", 1}, {"FOO", "1", 2}},
-                                      {"/includes"},
+                                      Utils::clone(systemIncludeSearchPaths),
+                                      Utils::clone(projectIncludeSearchPaths),
                                       {header1PathId},
-                                      {main1PathId}};
+                                      {main1PathId},
+                                      Utils::Language::Cxx,
+                                      Utils::LanguageVersion::CXX14,
+                                      Utils::LanguageExtension::None};
     ProjectPartContainer projectPart2{"project2",
-                                      {"-I", TESTDATA_DIR, "-x", "c++-header", "-Wno-pragma-once-outside-header"},
+                                      {"-Wno-pragma-once-outside-header"},
                                       {{"BAR", "1", 1}, {"FOO", "0", 2}},
-                                      {"/includes"},
+                                      Utils::clone(systemIncludeSearchPaths),
+                                      Utils::clone(projectIncludeSearchPaths),
                                       {header2PathId},
-                                      {main2PathId}};
+                                      {main2PathId},
+                                      Utils::Language::Cxx,
+                                      Utils::LanguageVersion::CXX14,
+                                      Utils::LanguageExtension::None};
     ProjectPartContainer projectPart3{"project3",
-                                      {"-I", TESTDATA_DIR, "-Wno-pragma-once-outside-header"},
+                                      {"-Wno-pragma-once-outside-header"},
                                       {{"BAR", "1", 1}, {"FOO", "1", 2}},
-                                      {"/includes", "/other/includes"},
+                                      Utils::clone(systemIncludeSearchPaths),
+                                      Utils::clone(projectIncludeSearchPaths),
                                       {header1PathId},
-                                      {main1PathId}};
+                                      {main1PathId},
+                                      Utils::Language::Cxx,
+                                      Utils::LanguageVersion::CXX14,
+                                      Utils::LanguageExtension::None};
     FileContainers unsaved{{{TESTDATA_DIR, "query_simplefunction.h"},
                             "void f();",
                             {}}};
@@ -191,8 +210,16 @@ protected:
     UsedMacros usedMacros{{"Foo", 1}};
     FileStatuses fileStatus{{2, 3, 4, false}};
     SourceDependencies sourceDependencies{{1, 2}, {1, 3}};
-    ClangBackEnd::ProjectPartArtefact artefact{"[\"-DFOO\"]", "{\"FOO\":\"1\",\"BAR\":\"1\"}", "[\"/includes\"]", 74};
-    ClangBackEnd::ProjectPartArtefact emptyArtefact{"", "", "", 74};
+    Utils::SmallString systemIncludeSearchPathsText{
+         R"([["/includes", 1, 2], [")" TESTDATA_DIR R"(" ,2 , 3], ["/other/includes", 3, 3]])"};
+    Utils::SmallString projectIncludeSearchPathsText{
+        R"([["/project/includes", 1, 1], ["/other/project/includes", 2, 1]])"};
+    ClangBackEnd::ProjectPartArtefact artefact{R"(["-DFOO"])",
+                                               R"([["FOO","1", 2],["BAR","1", 1]])",
+                                               systemIncludeSearchPathsText,
+                                               projectIncludeSearchPathsText,
+                                               74};
+    ClangBackEnd::ProjectPartArtefact emptyArtefact{"", "", "", "", 74};
     Utils::optional<ClangBackEnd::ProjectPartArtefact > nullArtefact;
     ClangBackEnd::ProjectPartPch projectPartPch{"/path/to/pch", 4};
     NiceMock<MockSqliteTransactionBackend> mockSqliteTransactionBackend;
@@ -204,7 +231,11 @@ protected:
     Manager collectorManger{generatedFiles};
     NiceMock<MockFunction<void(int, int)>> mockSetProgressCallback;
     ClangBackEnd::ProgressCounter progressCounter{mockSetProgressCallback.AsStdFunction()};
-    Scheduler indexerScheduler{collectorManger, indexerQueue, progressCounter, 1};
+    Scheduler indexerScheduler{collectorManger,
+                               indexerQueue,
+                               progressCounter,
+                               1,
+                               ClangBackEnd::CallDoInMainThreadAfterFinished::Yes};
     SymbolIndexerTaskQueue indexerQueue{indexerScheduler, progressCounter};
     ClangBackEnd::SymbolIndexer indexer{indexerQueue,
                                         mockSymbolStorage,
@@ -220,7 +251,25 @@ std::unique_ptr<Data> SymbolIndexer::data;
 
 TEST_F(SymbolIndexer, UpdateProjectPartsCallsAddFilesInCollector)
 {
-    EXPECT_CALL(mockCollector, setFile(main1PathId, projectPart1.arguments));
+    EXPECT_CALL(mockCollector,
+                setFile(main1PathId,
+                        ElementsAre("clang++",
+                                    "-Wno-pragma-once-outside-header",
+                                    "-x",
+                                    "c++-header",
+                                    "-std=c++14",
+                                    "-nostdinc",
+                                    "-nostdlibinc",
+                                    "-I",
+                                    "/project/includes",
+                                    "-I",
+                                    "/other/project/includes",
+                                    "-isystem",
+                                    TESTDATA_DIR,
+                                    "-isystem",
+                                    "/other/includes",
+                                    "-isystem",
+                                    "/includes")));
 
     indexer.updateProjectParts({projectPart1});
 }
@@ -230,14 +279,29 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsAddFilesWithPrecompiledHeaderInColl
     ON_CALL(mockSymbolStorage, fetchProjectPartArtefact(TypedEq<Utils::SmallStringView>(projectPart1.projectPartId))).WillByDefault(Return(emptyArtefact));
     ON_CALL(mockSymbolStorage, fetchPrecompiledHeader(Eq(artefact.projectPartId))).WillByDefault(Return(projectPartPch));
 
-    EXPECT_CALL(mockCollector, setFile(main1PathId,
-                                       ElementsAre(Eq("-I"),
-                                                   Eq(TESTDATA_DIR),
-                                                   Eq("-Wno-pragma-once-outside-header"),
-                                                   Eq("-Xclang"),
-                                                   Eq("-include-pch"),
-                                                   Eq("-Xclang"),
-                                                   Eq("/path/to/pch"))));
+    EXPECT_CALL(mockCollector,
+                setFile(main1PathId,
+                        ElementsAre("clang++",
+                                    "-Wno-pragma-once-outside-header",
+                                    "-x",
+                                    "c++-header",
+                                    "-std=c++14",
+                                    "-nostdinc",
+                                    "-nostdlibinc",
+                                    "-I",
+                                    "/project/includes",
+                                    "-I",
+                                    "/other/project/includes",
+                                    "-isystem",
+                                    TESTDATA_DIR,
+                                    "-isystem",
+                                    "/other/includes",
+                                    "-isystem",
+                                    "/includes",
+                                    "-Xclang",
+                                    "-include-pch",
+                                    "-Xclang",
+                                    "/path/to/pch")));
 
     indexer.updateProjectParts({projectPart1});
 }
@@ -246,10 +310,25 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsAddFilesWithoutPrecompiledHeaderInC
 {
     ON_CALL(mockSymbolStorage, fetchProjectPartArtefact(TypedEq<Utils::SmallStringView>(projectPart1.projectPartId))).WillByDefault(Return(emptyArtefact));
 
-    EXPECT_CALL(mockCollector, setFile(main1PathId,
-                                       ElementsAre(Eq("-I"),
-                                                   Eq(TESTDATA_DIR),
-                                                   Eq("-Wno-pragma-once-outside-header"))));
+    EXPECT_CALL(mockCollector,
+                setFile(main1PathId,
+                        ElementsAre("clang++",
+                                    "-Wno-pragma-once-outside-header",
+                                    "-x",
+                                    "c++-header",
+                                    "-std=c++14",
+                                    "-nostdinc",
+                                    "-nostdlibinc",
+                                    "-I",
+                                    "/project/includes",
+                                    "-I",
+                                    "/other/project/includes",
+                                    "-isystem",
+                                    TESTDATA_DIR,
+                                    "-isystem",
+                                    "/other/includes",
+                                    "-isystem",
+                                    "/includes")));
 
     indexer.updateProjectParts({projectPart1});
 }
@@ -313,14 +392,21 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsAddSymbolsAndSourceLocationsInStora
 
 TEST_F(SymbolIndexer, UpdateProjectPartsCallsUpdateProjectPartsInStorage)
 {
-    EXPECT_CALL(mockSymbolStorage, insertOrUpdateProjectPart(Eq("project1"),
-                                                       ElementsAre("-I", TESTDATA_DIR, "-Wno-pragma-once-outside-header"),
-                                                       ElementsAre(CompilerMacro{"BAR", "1", 1}, CompilerMacro{"FOO", "1", 2}),
-                                                       ElementsAre("/includes")));
-    EXPECT_CALL(mockSymbolStorage, insertOrUpdateProjectPart(Eq("project2"),
-                                                       ElementsAre("-I", TESTDATA_DIR, "-x", "c++-header", "-Wno-pragma-once-outside-header"),
-                                                       ElementsAre(CompilerMacro{"BAR", "1", 1}, CompilerMacro{"FOO", "0", 2}),
-                                                       ElementsAre("/includes")));
+    EXPECT_CALL(mockSymbolStorage,
+                insertOrUpdateProjectPart(
+                    Eq("project1"),
+                    ElementsAre("-Wno-pragma-once-outside-header"),
+                    ElementsAre(CompilerMacro{"BAR", "1", 1}, CompilerMacro{"FOO", "1", 2}),
+                    Eq(systemIncludeSearchPaths),
+                    Eq(projectIncludeSearchPaths)));
+    EXPECT_CALL(
+        mockSymbolStorage,
+        insertOrUpdateProjectPart(
+            Eq("project2"),
+            ElementsAre("-Wno-pragma-once-outside-header"),
+            ElementsAre(CompilerMacro{"BAR", "1", 1}, CompilerMacro{"FOO", "0", 2}),
+            Eq(systemIncludeSearchPaths),
+            Eq(projectIncludeSearchPaths)));
 
     indexer.updateProjectParts({projectPart1, projectPart2});
 }
@@ -328,7 +414,7 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsUpdateProjectPartsInStorage)
 TEST_F(SymbolIndexer, UpdateProjectPartsCallsUpdateProjectPartSourcesWithArtifact)
 {
     ON_CALL(mockSymbolStorage, fetchProjectPartArtefact(TypedEq<Utils::SmallStringView>("project1"))).WillByDefault(Return(artefact));
-    ON_CALL(mockSymbolStorage, insertOrUpdateProjectPart(Eq("project1"), _, _, _)).WillByDefault(Return(-1));
+    ON_CALL(mockSymbolStorage, insertOrUpdateProjectPart(Eq("project1"), _, _, _, _)).WillByDefault(Return(-1));
 
     EXPECT_CALL(mockSymbolStorage, updateProjectPartSources(_, _));
 
@@ -338,7 +424,7 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsUpdateProjectPartSourcesWithArtifac
 TEST_F(SymbolIndexer, UpdateProjectPartsCallsUpdateProjectPartSourcesWithoutArtifact)
 {
     ON_CALL(mockSymbolStorage, fetchProjectPartArtefact(TypedEq<Utils::SmallStringView>("project2"))).WillByDefault(Return(nullArtefact));
-    ON_CALL(mockSymbolStorage, insertOrUpdateProjectPart(Eq("project2"), _, _, _)).WillByDefault(Return(3));
+    ON_CALL(mockSymbolStorage, insertOrUpdateProjectPart(Eq("project2"), _, _, _, _)).WillByDefault(Return(3));
 
     EXPECT_CALL(mockSymbolStorage, updateProjectPartSources(3, ElementsAre(IsFileId(1), IsFileId(23))));
 
@@ -383,11 +469,35 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsInOrderWithoutProjectPartArtifact)
 
     EXPECT_CALL(mockSqliteTransactionBackend, immediateBegin());
     EXPECT_CALL(mockSymbolStorage, fetchProjectPartArtefact(TypedEq<Utils::SmallStringView>(projectPart1.projectPartId))).WillOnce(Return(nullArtefact));
-    EXPECT_CALL(mockSymbolStorage, insertOrUpdateProjectPart(Eq(projectPart1.projectPartId), Eq(projectPart1.arguments), Eq(projectPart1.compilerMacros), Eq(projectPart1.includeSearchPaths))).WillOnce(Return(12));
+    EXPECT_CALL(mockSymbolStorage,
+                insertOrUpdateProjectPart(Eq(projectPart1.projectPartId),
+                                          Eq(projectPart1.toolChainArguments),
+                                          Eq(projectPart1.compilerMacros),
+                                          Eq(projectPart1.systemIncludeSearchPaths),
+                                          Eq(projectPart1.projectIncludeSearchPaths)))
+        .WillOnce(Return(12));
     EXPECT_CALL(mockSymbolStorage, fetchPrecompiledHeader(Eq(12)));
     EXPECT_CALL(mockBuildDependenciesStorage, fetchLowestLastModifiedTime(Eq(main1PathId))).Times(0);
     EXPECT_CALL(mockSqliteTransactionBackend, commit());
-    EXPECT_CALL(mockCollector, setFile(main1PathId, projectPart1.arguments));
+    EXPECT_CALL(mockCollector,
+                setFile(main1PathId,
+                        ElementsAre("clang++",
+                                    "-Wno-pragma-once-outside-header",
+                                    "-x",
+                                    "c++-header",
+                                    "-std=c++14",
+                                    "-nostdinc",
+                                    "-nostdlibinc",
+                                    "-I",
+                                    "/project/includes",
+                                    "-I",
+                                    "/other/project/includes",
+                                    "-isystem",
+                                    TESTDATA_DIR,
+                                    "-isystem",
+                                    "/other/includes",
+                                    "-isystem",
+                                    "/includes")));
     EXPECT_CALL(mockCollector, collectSymbols());
     EXPECT_CALL(mockSqliteTransactionBackend, immediateBegin());
     EXPECT_CALL(mockSymbolStorage, addSymbolsAndSourceLocations(symbolEntries, sourceLocations));
@@ -406,11 +516,35 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsInOrderWithProjectPartArtifact)
 
     EXPECT_CALL(mockSqliteTransactionBackend, immediateBegin());
     EXPECT_CALL(mockSymbolStorage, fetchProjectPartArtefact(TypedEq<Utils::SmallStringView>(projectPart1.projectPartId))).WillRepeatedly(Return(artefact));
-    EXPECT_CALL(mockSymbolStorage, insertOrUpdateProjectPart(Eq(projectPart1.projectPartId), Eq(projectPart1.arguments), Eq(projectPart1.compilerMacros), Eq(projectPart1.includeSearchPaths))).WillOnce(Return(-1));
+    EXPECT_CALL(mockSymbolStorage,
+                insertOrUpdateProjectPart(Eq(projectPart1.projectPartId),
+                                          Eq(projectPart1.toolChainArguments),
+                                          Eq(projectPart1.compilerMacros),
+                                          Eq(projectPart1.systemIncludeSearchPaths),
+                                          Eq(projectPart1.projectIncludeSearchPaths)))
+        .WillOnce(Return(-1));
     EXPECT_CALL(mockSymbolStorage, fetchPrecompiledHeader(Eq(artefact.projectPartId)));
     EXPECT_CALL(mockBuildDependenciesStorage, fetchLowestLastModifiedTime(Eq(main1PathId))).WillOnce(Return(-1));
     EXPECT_CALL(mockSqliteTransactionBackend, commit());
-    EXPECT_CALL(mockCollector, setFile(Eq(main1PathId), Eq(projectPart1.arguments)));
+    EXPECT_CALL(mockCollector,
+                setFile(Eq(main1PathId),
+                        ElementsAre("clang++",
+                                    "-Wno-pragma-once-outside-header",
+                                    "-x",
+                                    "c++-header",
+                                    "-std=c++14",
+                                    "-nostdinc",
+                                    "-nostdlibinc",
+                                    "-I",
+                                    "/project/includes",
+                                    "-I",
+                                    "/other/project/includes",
+                                    "-isystem",
+                                    TESTDATA_DIR,
+                                    "-isystem",
+                                    "/other/includes",
+                                    "-isystem",
+                                    "/includes")));
     EXPECT_CALL(mockCollector, collectSymbols());
     EXPECT_CALL(mockSqliteTransactionBackend, immediateBegin());
     EXPECT_CALL(mockSymbolStorage, addSymbolsAndSourceLocations(symbolEntries, sourceLocations));
@@ -531,22 +665,57 @@ TEST_F(SymbolIndexer, CompilerMacrosAreDifferent)
     ASSERT_TRUE(areDifferent);
 }
 
-TEST_F(SymbolIndexer, IncludeSearchPathsAreDifferent)
+TEST_F(SymbolIndexer, SystemIncludeSearchPathsAreDifferent)
+{
+    ClangBackEnd::IncludeSearchPaths newSystemIncludeSearchPaths{
+        {"/includes", 1, ClangBackEnd::IncludeSearchPathType::BuiltIn},
+        {"/other/includes2", 2, ClangBackEnd::IncludeSearchPathType::System}};
+    ClangBackEnd::IncludeSearchPaths newProjectIncludeSearchPaths{
+        {"/project/includes", 1, ClangBackEnd::IncludeSearchPathType::User},
+        {"/other/project/includes2", 2, ClangBackEnd::IncludeSearchPathType::User}};
+    ProjectPartContainer projectPart3{
+        "project3",
+        {"-I", TESTDATA_DIR, "-Wno-pragma-once-outside-header"},
+        {{"BAR", "1", 1}, {"FOO", "1", 2}},
+        {{"/includes", 1, ClangBackEnd::IncludeSearchPathType::BuiltIn},
+         {"/other/includes2", 2, ClangBackEnd::IncludeSearchPathType::System}},
+        Utils::clone(projectIncludeSearchPaths),
+        {header1PathId},
+        {main1PathId},
+        Utils::Language::C,
+        Utils::LanguageVersion::C11,
+        Utils::LanguageExtension::All};
+    ON_CALL(mockSymbolStorage, fetchProjectPartArtefact(An<Utils::SmallStringView>()))
+        .WillByDefault(Return(artefact));
+
+    auto areDifferent = indexer.compilerMacrosOrIncludeSearchPathsAreDifferent(
+        projectPart3, artefact);
+
+    ASSERT_TRUE(areDifferent);
+}
+
+TEST_F(SymbolIndexer, ProjectIncludeSearchPathsAreDifferent)
 {
-    ProjectPartContainer projectPart3{"project3",
-                                      {"-I", TESTDATA_DIR, "-Wno-pragma-once-outside-header"},
-                                      {{"BAR", "1", 1}, {"FOO", "1", 2}},
-                                      {"/includes", "/other/includes"},
-                                      {header1PathId},
-                                      {main1PathId}};
-    ON_CALL(mockSymbolStorage, fetchProjectPartArtefact(An<Utils::SmallStringView>())).WillByDefault(Return(artefact));
+    ProjectPartContainer projectPart3{
+        "project3",
+        {"-I", TESTDATA_DIR, "-Wno-pragma-once-outside-header"},
+        {{"BAR", "1", 1}, {"FOO", "1", 2}},
+        Utils::clone(systemIncludeSearchPaths),
+        {{"/project/includes", 1, ClangBackEnd::IncludeSearchPathType::User},
+         {"/other/project/includes2", 2, ClangBackEnd::IncludeSearchPathType::User}},
+        {header1PathId},
+        {main1PathId},
+        Utils::Language::C,
+        Utils::LanguageVersion::C11,
+        Utils::LanguageExtension::All};
+    ON_CALL(mockSymbolStorage, fetchProjectPartArtefact(An<Utils::SmallStringView>()))
+        .WillByDefault(Return(artefact));
 
-    auto areDifferent = indexer.compilerMacrosOrIncludeSearchPathsAreDifferent(projectPart3,
-                                                                               artefact);
+    auto areDifferent = indexer.compilerMacrosOrIncludeSearchPathsAreDifferent(
+        projectPart3, artefact);
 
     ASSERT_TRUE(areDifferent);
 }
-
 TEST_F(SymbolIndexer, DontReparseInUpdateProjectPartsIfDefinesAreTheSame)
 {
     InSequence s;
@@ -554,7 +723,12 @@ TEST_F(SymbolIndexer, DontReparseInUpdateProjectPartsIfDefinesAreTheSame)
 
     EXPECT_CALL(mockSqliteTransactionBackend, immediateBegin());
     EXPECT_CALL(mockSymbolStorage, fetchProjectPartArtefact(TypedEq<Utils::SmallStringView>(projectPart1.projectPartId))).WillRepeatedly(Return(artefact));
-    EXPECT_CALL(mockSymbolStorage, insertOrUpdateProjectPart(Eq(projectPart1.projectPartId), Eq(projectPart1.arguments), Eq(projectPart1.compilerMacros), Eq(projectPart1.includeSearchPaths)));
+    EXPECT_CALL(mockSymbolStorage,
+                insertOrUpdateProjectPart(Eq(projectPart1.projectPartId),
+                                          Eq(projectPart1.toolChainArguments),
+                                          Eq(projectPart1.compilerMacros),
+                                          Eq(projectPart1.systemIncludeSearchPaths),
+                                          Eq(projectPart1.projectIncludeSearchPaths)));
     EXPECT_CALL(mockBuildDependenciesStorage, fetchLowestLastModifiedTime(A<FilePathId>())).WillRepeatedly(Return(QDateTime::currentSecsSinceEpoch()));
     EXPECT_CALL(mockSqliteTransactionBackend, commit());
     EXPECT_CALL(mockCollector, setFile(_, _)).Times(0);
@@ -649,6 +823,7 @@ TEST_F(SymbolIndexer, OutdatedFilesAreParsedInUpdateProjectParts)
 TEST_F(SymbolIndexer, UpToDateFilesAreNotParsedInUpdateProjectParts)
 {
     indexer.pathsChanged({main1PathId});
+
     indexerScheduler.syncTasks();
     ON_CALL(mockSymbolStorage, fetchProjectPartArtefact(An<Utils::SmallStringView>())).WillByDefault(Return(artefact));
     ON_CALL(mockBuildDependenciesStorage, fetchLowestLastModifiedTime(A<FilePathId>()))
diff --git a/tests/unit/unittest/symbolindexing-test.cpp b/tests/unit/unittest/symbolindexing-test.cpp
index 68a2cb8c65..41bf3a5c3b 100644
--- a/tests/unit/unittest/symbolindexing-test.cpp
+++ b/tests/unit/unittest/symbolindexing-test.cpp
@@ -30,7 +30,7 @@
 #include <querysqlitestatementfactory.h>
 
 #include <filepathcaching.h>
-#include <projectpartcontainerv2.h>
+#include <projectpartcontainer.h>
 #include <refactoringdatabaseinitializer.h>
 
 #include <QDir>
@@ -45,8 +45,8 @@ using ClangBackEnd::SymbolStorage;
 using ClangBackEnd::FilePathCaching;
 using ClangBackEnd::FilePathId;
 using ClangBackEnd::RefactoringDatabaseInitializer;
-using ClangBackEnd::V2::ProjectPartContainer;
-using ClangBackEnd::V2::ProjectPartContainer;
+using ClangBackEnd::ProjectPartContainer;
+using ClangBackEnd::ProjectPartContainer;
 using ClangRefactoring::SymbolQuery;
 using ClangRefactoring::QuerySqliteStatementFactory;
 using Utils::PathString;
@@ -88,11 +88,15 @@ protected:
     Query query{queryFactory};
     PathString main1Path = TESTDATA_DIR "/symbolindexing_main1.cpp";
     ProjectPartContainer projectPart1{"project1",
-                                      {"cc", "-I", TESTDATA_DIR, "-std=c++1z"},
+                                      {},
                                       {{"DEFINE", "1", 1}},
-                                      {"/includes"},
+                                      {{TESTDATA_DIR, 1, ClangBackEnd::IncludeSearchPathType::System}},
+                                      {},
                                       {},
-                                      {filePathId(main1Path)}};
+                                      {filePathId(main1Path)},
+                                      Utils::Language::Cxx,
+                                      Utils::LanguageVersion::CXX14,
+                                      Utils::LanguageExtension::None};
 };
 
 TEST_F(SymbolIndexing, Locations)
diff --git a/tests/unit/unittest/symbolstorage-test.cpp b/tests/unit/unittest/symbolstorage-test.cpp
index 266540c62b..4a3958212b 100644
--- a/tests/unit/unittest/symbolstorage-test.cpp
+++ b/tests/unit/unittest/symbolstorage-test.cpp
@@ -35,18 +35,21 @@
 
 namespace {
 
-using Utils::PathString;
-using ClangBackEnd::FilePathId;
 using ClangBackEnd::FilePathCachingInterface;
-using ClangBackEnd::SymbolEntries;
-using ClangBackEnd::SymbolEntry;
+using ClangBackEnd::FilePathId;
+using ClangBackEnd::IncludeSearchPath;
+using ClangBackEnd::IncludeSearchPaths;
+using ClangBackEnd::IncludeSearchPathType;
 using ClangBackEnd::SourceLocationEntries;
 using ClangBackEnd::SourceLocationEntry;
-using ClangBackEnd::SymbolIndex;
 using ClangBackEnd::SourceLocationKind;
+using ClangBackEnd::SymbolEntries;
+using ClangBackEnd::SymbolEntry;
+using ClangBackEnd::SymbolIndex;
 using ClangBackEnd::SymbolKind;
 using Sqlite::Database;
 using Sqlite::Table;
+using Utils::PathString;
 
 using Storage = ClangBackEnd::SymbolStorage<MockSqliteDatabase>;
 
@@ -65,8 +68,7 @@ protected:
     MockSqliteWriteStatement &insertNewLocationsInLocationsStatement = storage.m_insertNewLocationsInLocationsStatement;
     MockSqliteWriteStatement &deleteNewSymbolsTableStatement = storage.m_deleteNewSymbolsTableStatement;
     MockSqliteWriteStatement &deleteNewLocationsTableStatement = storage.m_deleteNewLocationsTableStatement;
-    MockSqliteWriteStatement &insertProjectPartStatement = storage.m_insertProjectPartStatement;
-    MockSqliteWriteStatement &updateProjectPartStatement = storage.m_updateProjectPartStatement;
+    MockSqliteWriteStatement &insertOrUpdateProjectPartStatement = storage.m_insertOrUpdateProjectPartStatement;
     MockSqliteReadStatement &getProjectPartIdStatement = storage.m_getProjectPartIdStatement;
     MockSqliteWriteStatement &deleteAllProjectPartsSourcesWithProjectPartIdStatement = storage.m_deleteAllProjectPartsSourcesWithProjectPartIdStatement;
     MockSqliteWriteStatement &insertProjectPartSourcesStatement = storage.m_insertProjectPartSourcesStatement;
@@ -78,7 +80,21 @@ protected:
                                 {2, {"function2USR", "function2", SymbolKind::Function}}};
     SourceLocationEntries sourceLocations{{1, 3, {42, 23}, SourceLocationKind::Declaration},
                                           {2, 4, {7, 11}, SourceLocationKind::Definition}};
-    ClangBackEnd::ProjectPartArtefact artefact{"[\"-DFOO\"]", "{\"FOO\":\"1\"}", "[\"/includes\"]", 74};
+    IncludeSearchPaths systemIncludeSearchPaths{
+        {"/includes", 1, IncludeSearchPathType::BuiltIn},
+        {"/other/includes", 2, IncludeSearchPathType::System}};
+    IncludeSearchPaths projectIncludeSearchPaths{
+        {"/project/includes", 1, IncludeSearchPathType::User},
+        {"/other/project/includes", 2, IncludeSearchPathType::User}};
+    Utils::SmallString systemIncludeSearchPathsText{
+        R"([["/includes",1,2],["/other/includes",2,3]])"};
+    Utils::SmallString projectIncludeSearchPathsText{
+        R"([["/project/includes",1,1],["/other/project/includes",2,1]])"};
+    ClangBackEnd::ProjectPartArtefact artefact{R"(["-DFOO"])",
+                                               R"([["FOO","1",1]])",
+                                               systemIncludeSearchPathsText,
+                                               projectIncludeSearchPathsText,
+                                               74};
 };
 
 TEST_F(SymbolStorage, CreateAndFillTemporaryLocationsTable)
@@ -167,43 +183,24 @@ TEST_F(SymbolStorage, ConvertStringsToJson)
     ASSERT_THAT(jsonText, Eq("[\"foo\",\"bar\",\"foo\"]"));
 }
 
-TEST_F(SymbolStorage, InsertProjectPart)
+TEST_F(SymbolStorage, InsertOrUpdateProjectPart)
 {
     InSequence sequence;
-    ON_CALL(mockDatabase, lastInsertedRowId()).WillByDefault(Return(1));
 
-    EXPECT_CALL(mockDatabase, setLastInsertedRowId(-1));
-    EXPECT_CALL(insertProjectPartStatement,
+    EXPECT_CALL(insertOrUpdateProjectPartStatement,
                 write(TypedEq<Utils::SmallStringView>("project"),
-                      TypedEq<Utils::SmallStringView>("[\"foo\"]"),
-                      TypedEq<Utils::SmallStringView>("{\"FOO\":\"1\"}"),
-                      TypedEq<Utils::SmallStringView>("[\"/includes\"]")));
-    EXPECT_CALL(mockDatabase, lastInsertedRowId()).Times(2);
-
-    storage.insertOrUpdateProjectPart("project",  {"foo"}, {{"FOO", "1", 1}}, {"/includes"});
+                      TypedEq<Utils::SmallStringView>(R"(["foo"])"),
+                      TypedEq<Utils::SmallStringView>(R"([["FOO","1",1]])"),
+                      TypedEq<Utils::SmallStringView>(systemIncludeSearchPathsText),
+                      TypedEq<Utils::SmallStringView>(projectIncludeSearchPathsText)));
+    EXPECT_CALL(
+        getProjectPartIdStatement, valueReturnInt32(TypedEq<Utils::SmallStringView>("project")))
+        .WillOnce(Return(74));
+
+    storage.insertOrUpdateProjectPart(
+        "project", {"foo"}, {{"FOO", "1", 1}}, systemIncludeSearchPaths, projectIncludeSearchPaths);
 }
 
-TEST_F(SymbolStorage, UpdateProjectPart)
-{
-    InSequence sequence;
-    ON_CALL(mockDatabase, lastInsertedRowId()).WillByDefault(Return(-1));
-
-    EXPECT_CALL(mockDatabase, setLastInsertedRowId(-1));
-    EXPECT_CALL(insertProjectPartStatement,
-                write(TypedEq<Utils::SmallStringView>("project"),
-                      TypedEq<Utils::SmallStringView>("[\"foo\"]"),
-                      TypedEq<Utils::SmallStringView>("{\"FOO\":\"1\"}"),
-                      TypedEq<Utils::SmallStringView>("[\"/includes\"]")));
-    EXPECT_CALL(mockDatabase, lastInsertedRowId());
-    EXPECT_CALL(updateProjectPartStatement,
-                write(TypedEq<Utils::SmallStringView>("[\"foo\"]"),
-                      TypedEq<Utils::SmallStringView>("{\"FOO\":\"1\"}"),
-                      TypedEq<Utils::SmallStringView>("[\"/includes\"]"),
-                      TypedEq<Utils::SmallStringView>("project")));
-    EXPECT_CALL(mockDatabase, lastInsertedRowId());
-
-    storage.insertOrUpdateProjectPart("project",  {"foo"}, {{"FOO", "1", 1}}, {"/includes"});
-}
 
 TEST_F(SymbolStorage, UpdateProjectPartSources)
 {
diff --git a/tests/unit/unittest/taskscheduler-test.cpp b/tests/unit/unittest/taskscheduler-test.cpp
index 9afc52a724..7b6d0bbcbf 100644
--- a/tests/unit/unittest/taskscheduler-test.cpp
+++ b/tests/unit/unittest/taskscheduler-test.cpp
@@ -68,14 +68,16 @@ protected:
     NiceMock<MockFunction<void(int, int)>> mockSetProgressCallback;
     ClangBackEnd::ProgressCounter progressCounter{mockSetProgressCallback.AsStdFunction()};
     Scheduler scheduler{mockProcessorManager,
-                mockSymbolIndexerTaskQueue,
-                progressCounter,
-                4};
+                        mockSymbolIndexerTaskQueue,
+                        progressCounter,
+                        4,
+                        ClangBackEnd::CallDoInMainThreadAfterFinished::Yes};
     Scheduler deferredScheduler{mockProcessorManager,
-                mockSymbolIndexerTaskQueue,
-                progressCounter,
-                4,
-                std::launch::deferred};
+                                mockSymbolIndexerTaskQueue,
+                                progressCounter,
+                                4,
+                                ClangBackEnd::CallDoInMainThreadAfterFinished::Yes,
+                                std::launch::deferred};
 };
 
 TEST_F(TaskScheduler, AddTasks)
@@ -146,6 +148,24 @@ TEST_F(TaskScheduler, FreeSlotsCallsCleanupMethodsAfterTheWorkIsDone)
     scheduler.slotUsage();
 }
 
+TEST_F(TaskScheduler, FreeSlotsDoNotCallsDoInMainThreadAfterFinishedAfterTheWorkIsDoneIfForbidden)
+{
+    Scheduler scheduler{mockProcessorManager,
+                        mockSymbolIndexerTaskQueue,
+                        progressCounter,
+                        4,
+                        ClangBackEnd::CallDoInMainThreadAfterFinished::No};
+    scheduler.addTasks({nocall, nocall});
+    scheduler.syncTasks();
+    InSequence s;
+
+    EXPECT_CALL(mockSymbolsCollector, doInMainThreadAfterFinished()).Times(0);
+
+    scheduler.slotUsage();
+    scheduler.syncTasks();
+    QCoreApplication::processEvents();
+}
+
 TEST_F(TaskScheduler, FreeSlotsCallsProgressMethodsAfterTheWorkIsDone)
 {
     scheduler.addTasks({nocall, nocall});
diff --git a/tests/unit/unittest/testenvironment.h b/tests/unit/unittest/testenvironment.h
index 8b6ef89710..a9529c58d5 100644
--- a/tests/unit/unittest/testenvironment.h
+++ b/tests/unit/unittest/testenvironment.h
@@ -44,11 +44,6 @@ public:
         return temporaryDirectory.path();
     }
 
-    QString clangCompilerPath() const override
-    {
-        return QString::fromUtf8(CLANG_COMPILER_PATH);
-    }
-
     uint hardwareConcurrency() const
     {
         return 2;
diff --git a/tests/unit/unittest/toolchainargumentscache-test.cpp b/tests/unit/unittest/toolchainargumentscache-test.cpp
new file mode 100644
index 0000000000..8f032fa43d
--- /dev/null
+++ b/tests/unit/unittest/toolchainargumentscache-test.cpp
@@ -0,0 +1,199 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#include "googletest.h"
+
+#include <toolchainargumentscache.h>
+
+namespace {
+
+using ClangBackEnd::ProjectPartContainer;
+
+MATCHER_P2(IsEntry,
+           projectPartIds,
+           arguments,
+           std::string(negation ? "isn't " : "is ")
+               + PrintToString(ClangBackEnd::ArgumentsEntry(projectPartIds.clone(), arguments)))
+{
+    const ClangBackEnd::ArgumentsEntry &entry= arg;
+
+    return entry.ids == projectPartIds && entry.arguments == arguments;
+}
+
+class ToolChainArgumentsCache : public testing::Test
+{
+public:
+    ClangBackEnd::ToolChainsArgumentsCache cache;
+    ProjectPartContainer projectPart1{"project1", {}, {}, {}, {}, {}, {}, {}, {}, {}};
+    ProjectPartContainer projectPart2{"project2", {}, {}, {}, {}, {}, {}, {}, {}, {}};
+    ProjectPartContainer projectPart3{"project3", {}, {}, {}, {}, {}, {}, {}, {}, {}};
+    ProjectPartContainer projectPart4{"project4", {}, {}, {}, {}, {}, {}, {}, {}, {}};
+    Utils::SmallStringVector arguments1{"yi", "er"};
+    Utils::SmallStringVector arguments2{"san", "se"};
+};
+
+TEST_F(ToolChainArgumentsCache, ArgumentsDoesNotExistForProjectPartId)
+{
+    cache.update({projectPart2, projectPart4}, arguments2);
+
+    ASSERT_THAT(cache.arguments({projectPart1.projectPartId}), IsEmpty());
+}
+
+TEST_F(ToolChainArgumentsCache, AddNewArguments)
+{
+    cache.update({projectPart2, projectPart4}, arguments2);
+
+    cache.update({projectPart1, projectPart3}, arguments1);
+
+    ASSERT_THAT(
+        cache.arguments({projectPart1.projectPartId}),
+        ElementsAre(IsEntry(Utils::SmallStringVector{projectPart1.projectPartId}, arguments1)));
+}
+
+TEST_F(ToolChainArgumentsCache, AddDifferentProjectParts)
+{
+    cache.update({projectPart1, projectPart3}, arguments1);
+
+    cache.update({projectPart2, projectPart4}, arguments1);
+
+    ASSERT_THAT(
+        cache.arguments(Utils::SmallStringVector{projectPart2.projectPartId}),
+        ElementsAre(IsEntry(Utils::SmallStringVector{projectPart2.projectPartId}, arguments1)));
+}
+
+TEST_F(ToolChainArgumentsCache, AddDifferentProjectPartsReverseOrder)
+{
+    cache.update({projectPart2, projectPart3}, arguments1);
+
+    cache.update({projectPart1, projectPart4}, arguments1);
+
+    ASSERT_THAT(
+        cache.arguments(Utils::SmallStringVector{projectPart2.projectPartId}),
+        ElementsAre(IsEntry(Utils::SmallStringVector{projectPart2.projectPartId}, arguments1)));
+}
+
+TEST_F(ToolChainArgumentsCache, AddDifferentProjectPartsDoesNotRemoveOldEntry)
+{
+    cache.update({projectPart1, projectPart3}, arguments1);
+
+    cache.update({projectPart2, projectPart4}, arguments1);
+
+    ASSERT_THAT(
+        cache.arguments(Utils::SmallStringVector{projectPart1.projectPartId}),
+        ElementsAre(IsEntry(Utils::SmallStringVector{projectPart1.projectPartId}, arguments1)));
+}
+
+TEST_F(ToolChainArgumentsCache, AddSameArgumentsDoesNotIncreseEntryCount)
+{
+    cache.update({projectPart1, projectPart3}, arguments1);
+
+    cache.update({projectPart2, projectPart4}, arguments1);
+
+    ASSERT_THAT(cache.size(), 1);
+}
+
+TEST_F(ToolChainArgumentsCache, AddDifferentArgumentsDoesIncreseEntryCount)
+{
+    cache.update({projectPart1, projectPart3}, arguments1);
+
+    cache.update({projectPart2, projectPart4}, arguments2);
+
+    ASSERT_THAT(cache.size(), 2);
+}
+
+TEST_F(ToolChainArgumentsCache, RemoveIdsFromOtherEntries)
+{
+    cache.update({projectPart2, projectPart4}, arguments1);
+    cache.update({projectPart1, projectPart3}, arguments1);
+
+    cache.update({projectPart2, projectPart4}, arguments2);
+
+    ASSERT_THAT(
+        cache.arguments(Utils::SmallStringVector{projectPart2.projectPartId}),
+        ElementsAre(IsEntry(Utils::SmallStringVector{projectPart2.projectPartId}, arguments2)));
+}
+
+TEST_F(ToolChainArgumentsCache, RemoveIdsFromOtherEntriesWithArgumentsAlreadyExists)
+{
+    cache.update({projectPart2, projectPart4}, arguments1);
+    cache.update({projectPart1, projectPart3}, arguments2);
+
+    cache.update({projectPart2, projectPart4}, arguments2);
+
+    ASSERT_THAT(
+        cache.arguments({projectPart2.projectPartId}),
+        ElementsAre(IsEntry(Utils::SmallStringVector{projectPart2.projectPartId}, arguments2)));
+}
+
+TEST_F(ToolChainArgumentsCache, RemoveEntryIfEmpty)
+{
+    cache.update({projectPart2, projectPart4}, arguments2);
+    cache.update({projectPart1, projectPart3}, arguments1);
+
+    cache.update({projectPart2, projectPart4}, arguments1);
+
+    ASSERT_THAT(cache.size(), 1);
+}
+
+TEST_F(ToolChainArgumentsCache, GetMutipleEntries)
+{
+    cache.update({projectPart2, projectPart4}, arguments1);
+    cache.update({projectPart1, projectPart3}, arguments2);
+
+    auto arguments = cache.arguments(
+        {projectPart1.projectPartId, projectPart2.projectPartId, projectPart3.projectPartId});
+
+    ASSERT_THAT(
+        arguments,
+        ElementsAre(IsEntry(Utils::SmallStringVector{projectPart2.projectPartId}, arguments1),
+                    IsEntry(Utils::SmallStringVector{projectPart1.projectPartId,
+                                                     projectPart3.projectPartId},
+                            arguments2)));
+}
+
+TEST_F(ToolChainArgumentsCache, RemoveMutipleIds)
+{
+    cache.update({projectPart2, projectPart4}, arguments1);
+    cache.update({projectPart1, projectPart3}, arguments2);
+
+    cache.remove({projectPart1.projectPartId, projectPart2.projectPartId});
+
+    ASSERT_THAT(
+        cache.arguments(
+            {projectPart1.projectPartId, projectPart2.projectPartId, projectPart3.projectPartId}),
+        ElementsAre(IsEntry(Utils::SmallStringVector{projectPart3.projectPartId}, arguments2)));
+}
+
+TEST_F(ToolChainArgumentsCache, RemoveEntriesIfEntryIsEmptyAfterRemovingIds)
+{
+    cache.update({projectPart2, projectPart4}, arguments1);
+    cache.update({projectPart1, projectPart3}, arguments2);
+
+    cache.remove({projectPart1.projectPartId, projectPart3.projectPartId});
+
+    ASSERT_THAT(cache.size(), 1);
+}
+
+} // namespace
diff --git a/tests/unit/unittest/unittest.pro b/tests/unit/unittest/unittest.pro
index f6eded4a58..431207371d 100644
--- a/tests/unit/unittest/unittest.pro
+++ b/tests/unit/unittest/unittest.pro
@@ -99,7 +99,6 @@ SOURCES += \
     sourcesmanager-test.cpp \
     symbolindexertaskqueue-test.cpp \
     refactoringprojectupdater-test.cpp \
-    projectpartqueue-test.cpp \
     processormanager-test.cpp \
     taskscheduler-test.cpp \
     compileroptionsbuilder-test.cpp \
@@ -111,7 +110,10 @@ SOURCES += \
     usedmacrofilter-test.cpp \
     pchtasksmerger-test.cpp \
     pchtaskqueue-test.cpp \
-    headerpathfilter-test.cpp
+    commandlinebuilder-test.cpp \
+    headerpathfilter-test.cpp \
+    toolchainargumentscache-test.cpp \
+    modifiedtimechecker-test.cpp
 
 !isEmpty(LIBCLANG_LIBS) {
 SOURCES += \
@@ -262,7 +264,8 @@ HEADERS += \
     mockbuilddependenciesstorage.h \
     mockbuilddependencygenerator.h \
     mockpchtasksmerger.h \
-    mockpchtaskqueue.h
+    mockpchtaskqueue.h \
+    mockpchtaskgenerator.h
 
 !isEmpty(LIBCLANG_LIBS) {
 HEADERS += \
diff --git a/tests/unit/unittest/usedmacrofilter-test.cpp b/tests/unit/unittest/usedmacrofilter-test.cpp
index 93a29d9c9a..871d4a8535 100644
--- a/tests/unit/unittest/usedmacrofilter-test.cpp
+++ b/tests/unit/unittest/usedmacrofilter-test.cpp
@@ -69,6 +69,20 @@ TEST_F(UsedMacroFilter, ProjectIncludes)
     ASSERT_THAT(filter.projectIncludes, ElementsAre(FilePathId{3}, FilePathId{5}));
 }
 
+TEST_F(UsedMacroFilter, TopSystemIncludes)
+{
+    ClangBackEnd::UsedMacroFilter filter(includes, usedMacros);
+
+    ASSERT_THAT(filter.topSystemIncludes, ElementsAre(FilePathId{4}));
+}
+
+TEST_F(UsedMacroFilter, TopProjectIncludes)
+{
+    ClangBackEnd::UsedMacroFilter filter(includes, usedMacros);
+
+    ASSERT_THAT(filter.topProjectIncludes, ElementsAre(FilePathId{5}));
+}
+
 TEST_F(UsedMacroFilter, SystemUsedMacros)
 {
     ClangBackEnd::UsedMacroFilter filter(includes, usedMacros);