Autodetect clang-cl by using Probe

This allows to build projects without calling "qbs setup-toolchains"
first by simply calling "qbs build qbs.toolchainType:clang-cl"

Change-Id: I86d135ddf2cb588f322709e4e7a265cb6fd7772f
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

9 files changed, 384 insertions, 113 deletions

diff --git a/share/qbs/imports/qbs/Probes/ClangClBinaryProbe.qbs b/share/qbs/imports/qbs/Probes/ClangClBinaryProbe.qbs
new file mode 100644
index 000000000..f4916a37a
--- /dev/null
+++ b/share/qbs/imports/qbs/Probes/ClangClBinaryProbe.qbs
@@ -0,0 +1,73 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 Ivan Komissarov (abbapoh@gmail.com)
+** Contact: http://www.qt.io/licensing
+**
+** This file is part of Qbs.
+**
+** 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 http://www.qt.io/terms-conditions. For further information
+** use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, The Qt Company gives you certain additional
+** rights.  These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+import qbs.FileInfo
+import qbs.ModUtils
+import qbs.Utilities
+import "path-probe.js" as PathProbeConfigure
+
+BinaryProbe {
+    // output
+    property string vcvarsallPath;
+
+    configure: {
+        var _selectors;
+        var results = PathProbeConfigure.configure(_selectors, names, nameSuffixes, nameFilter,
+                                                   candidateFilter, searchPaths, pathSuffixes,
+                                                   platformSearchPaths, environmentPaths,
+                                                   platformEnvironmentPaths, pathListSeparator);
+        var compilerPath;
+        if (results.found)
+            compilerPath = results.files[0].filePath;
+        var compilers = Utilities.installedClangCls(compilerPath);
+        if (compilers.length >= 1) {
+            var result = {};
+            result.fileName = "clang-cl.exe";
+            result.path = compilers[0].toolchainInstallPath;
+            result.filePath = FileInfo.joinPaths(result.path, result.fileName);
+            result.candidatePaths = result.filePath;
+            result.vcvarsallPath = compilers[0].vcvarsallPath;
+            results.found = true;
+            results.files = [result];
+        }
+
+        found = results.found;
+        allResults = results.files;
+
+        if (allResults.length === 1) {
+            var result = allResults[0];
+            candidatePaths = result.candidatePaths;
+            path = result.path;
+            filePath = result.filePath;
+            fileName = result.fileName;
+            vcvarsallPath = result.vcvarsallPath;
+        }
+    }
+}
diff --git a/share/qbs/modules/cpp/windows-clang-cl.qbs b/share/qbs/modules/cpp/windows-clang-cl.qbs
index d57f5a7ad..a34a67ad2 100644
--- a/share/qbs/modules/cpp/windows-clang-cl.qbs
+++ b/share/qbs/modules/cpp/windows-clang-cl.qbs
@@ -40,7 +40,7 @@ MsvcBaseModule {
                qbs.toolchain && qbs.toolchain.contains('clang-cl')
     priority: 100
 
-    Probes.BinaryProbe {
+    Probes.ClangClBinaryProbe {
         id: clangPathProbe
         condition: !toolchainInstallPath && !_skipAllChecks
         names: ["clang-cl"]
@@ -78,7 +78,7 @@ MsvcBaseModule {
         driverLinkerFlags: "-fuse-ld=" + linkerVariant
     }
 
-    property string vcvarsallPath
+    property string vcvarsallPath : clangPathProbe.found ? clangPathProbe.vcvarsallPath : undefined
 
     compilerName: "clang-cl.exe"
     linkerName: "lld-link.exe"
diff --git a/src/app/qbs-setup-toolchains/clangclprobe.cpp b/src/app/qbs-setup-toolchains/clangclprobe.cpp
index ee445a2fb..6eff83217 100644
--- a/src/app/qbs-setup-toolchains/clangclprobe.cpp
+++ b/src/app/qbs-setup-toolchains/clangclprobe.cpp
@@ -44,6 +44,7 @@
 #include "../shared/logging/consolelogger.h"
 
 #include <logging/translator.h>
+#include <tools/clangclinfo.h>
 #include <tools/hostosinfo.h>
 #include <tools/msvcinfo.h>
 #include <tools/profile.h>
@@ -55,6 +56,7 @@
 
 using qbs::Settings;
 using qbs::Profile;
+using qbs::Internal::ClangClInfo;
 using qbs::Internal::HostOsInfo;
 using qbs::Internal::MSVC;
 using qbs::Internal::MSVCInstallInfo;
@@ -63,11 +65,6 @@ using qbs::Internal::Tr;
 
 namespace {
 
-QString getToolchainInstallPath(const QFileInfo &compiler)
-{
-    return compiler.path(); // 1 level up
-}
-
 Profile createProfileHelper(
         Settings *settings,
         const QString &profileName,
@@ -88,90 +85,13 @@ Profile createProfileHelper(
     return profile;
 }
 
-std::vector<MSVCInstallInfo> compatibleMsvcs()
-{
-    auto msvcs = MSVCInstallInfo::installedMSVCs(ConsoleLogger::instance());
-    auto filter = [](const MSVCInstallInfo &info)
-    {
-        const auto versions = info.version.split(QLatin1Char('.'));
-        if (versions.empty())
-            return true;
-        bool ok = false;
-        const int major = versions.at(0).toInt(&ok);
-        return !(ok && major >= 15); // support MSVC2017 and above
-    };
-    const auto it = std::remove_if(msvcs.begin(), msvcs.end(), filter);
-    msvcs.erase(it, msvcs.end());
-    for (const auto &msvc: msvcs) {
-        auto vcvarsallPath = msvc.findVcvarsallBat();
-        if (vcvarsallPath.isEmpty())
-            continue;
-    }
-    return msvcs;
-}
-
-QString findCompatibleVcsarsallBat(const std::vector<MSVCInstallInfo> &msvcs)
+QString findClangCl()
 {
-    for (const auto &msvc: msvcs) {
-        const auto vcvarsallPath = msvc.findVcvarsallBat();
-        if (!vcvarsallPath.isEmpty())
-            return vcvarsallPath;
-    }
-    return {};
-}
-
-QString wow6432Key()
-{
-#ifdef Q_OS_WIN64
-    return QStringLiteral("\\Wow6432Node");
-#else
-    return {};
-#endif
-}
-
-// Function can modify passed list in case it has found clang in one of the VS installation -
-// in that case, there's no point in looking for vcvarsall.bat among all installed VSs, we just
-// use .bat file corresponding to that particular VS installation
-QString findClangCl(std::vector<MSVCInstallInfo> *msvcs)
-{
-    Q_ASSERT(msvcs);
     const auto compilerName = HostOsInfo::appendExecutableSuffix(QStringLiteral("clang-cl"));
     const auto compilerFromPath = findExecutable(compilerName);
     if (!compilerFromPath.isEmpty())
         return compilerFromPath;
 
-    const QSettings registry(
-            QStringLiteral("HKEY_LOCAL_MACHINE\\SOFTWARE%1\\LLVM\\LLVM").arg(wow6432Key()),
-            QSettings::NativeFormat);
-    const auto key = QStringLiteral(".");
-    if (registry.contains(key)) {
-        const auto compilerPath = QDir::fromNativeSeparators(registry.value(key).toString())
-                + QStringLiteral("/bin/") + compilerName;
-        if (QFileInfo(compilerPath).exists())
-            return compilerPath;
-    }
-
-    // this branch can be useful in case user had two LLVM installations (e.g. 32bit & 64bit)
-    // but uninstalled one - in that case, registry will be empty
-    static const char * const envVarCandidates[] = {"ProgramFiles", "ProgramFiles(x86)"};
-    for (const auto &envVar : envVarCandidates) {
-        const auto value
-                = QDir::fromNativeSeparators(QString::fromLocal8Bit(qgetenv(envVar)));
-        const auto compilerPath = value + QStringLiteral("/LLVM/bin/") + compilerName;
-        if (QFileInfo(compilerPath).exists())
-            return compilerPath;
-    }
-
-    // If we didn't find custom LLVM installation, try to find if it's installed with Visual Studio
-    for (const auto &msvc : *msvcs) {
-        const auto compilerPath = QStringLiteral("%1/VC/Tools/Llvm/bin/%2")
-                .arg(msvc.installDir, compilerName);
-        if (QFileInfo(compilerPath).exists()) {
-            *msvcs = {msvc}; // reduce list to one installation
-            return compilerPath;
-        }
-    }
-
     return {};
 }
 
@@ -180,18 +100,13 @@ QString findClangCl(std::vector<MSVCInstallInfo> *msvcs)
 void createClangClProfile(const QFileInfo &compiler, Settings *settings,
                           const QString &profileName)
 {
-    const auto compilerName = QStringLiteral("clang-cl");
-    const auto vcvarsallPath = findCompatibleVcsarsallBat(compatibleMsvcs());
-    if (vcvarsallPath.isEmpty()) {
-        qbsWarning()
-                << Tr::tr("%1 requires installed Visual Studio 2017 or newer, but none was found.")
-                   .arg(compilerName);
+    const auto clangCl = ClangClInfo::fromCompilerFilePath(
+            compiler.filePath(), ConsoleLogger::instance());
+    if (clangCl.isEmpty())
         return;
-    }
-
-    const auto toolchainInstallPath = getToolchainInstallPath(compiler);
     const auto hostArch = QString::fromStdString(HostOsInfo::hostOSArchitecture());
-    createProfileHelper(settings, profileName, toolchainInstallPath, vcvarsallPath, hostArch);
+    createProfileHelper(
+            settings, profileName, clangCl.toolchainInstallPath, clangCl.vcvarsallPath, hostArch);
 }
 
 /*!
@@ -200,33 +115,24 @@ void createClangClProfile(const QFileInfo &compiler, Settings *settings,
 */
 void clangClProbe(Settings *settings, std::vector<Profile> &profiles)
 {
-    auto msvcs = compatibleMsvcs();
-
     const auto compilerName = QStringLiteral("clang-cl");
     qbsInfo() << Tr::tr("Trying to detect %1...").arg(compilerName);
-    const QString compilerFilePath = findClangCl(&msvcs);
-    if (compilerFilePath.isEmpty()) {
+    const auto clangCls = ClangClInfo::installedCompilers(
+            {findClangCl()}, ConsoleLogger::instance());
+    if (clangCls.empty()) {
         qbsInfo() << Tr::tr("%1 was not found.").arg(compilerName);
         return;
     }
-    const QFileInfo compiler(compilerFilePath);
-    const auto vcvarsallPath = findCompatibleVcsarsallBat(msvcs);
-    if (vcvarsallPath.isEmpty()) {
-        qbsWarning()
-                << Tr::tr("%1 requires installed Visual Studio 2017 or newer, but none was found.")
-                        .arg(compilerName);
-        return;
-    }
 
+    const auto clangCl = clangCls.front();
     const QString architectures[] = {
         QStringLiteral("x86_64"),
         QStringLiteral("x86")
     };
-    const auto toolchainInstallPath = getToolchainInstallPath(compiler);
     for (const auto &arch: architectures) {
         const auto profileName = QStringLiteral("clang-cl-%1").arg(arch);
         auto profile = createProfileHelper(
-                settings, profileName, toolchainInstallPath, vcvarsallPath, arch);
+                settings, profileName, clangCl.toolchainInstallPath, clangCl.vcvarsallPath, arch);
         profiles.push_back(std::move(profile));
     }
 }
diff --git a/src/lib/corelib/corelib.qbs b/src/lib/corelib/corelib.qbs
index bd44ac3ed..619c0f0e3 100644
--- a/src/lib/corelib/corelib.qbs
+++ b/src/lib/corelib/corelib.qbs
@@ -395,6 +395,8 @@ QbsLibrary {
             "buildgraphlocker.cpp",
             "buildgraphlocker.h",
             "buildoptions.cpp",
+            "clangclinfo.cpp",
+            "clangclinfo.h",
             "cleanoptions.cpp",
             "codelocation.cpp",
             "commandechomode.cpp",
diff --git a/src/lib/corelib/jsextensions/utilitiesextension.cpp b/src/lib/corelib/jsextensions/utilitiesextension.cpp
index 2d29cb7c5..6c693cb61 100644
--- a/src/lib/corelib/jsextensions/utilitiesextension.cpp
+++ b/src/lib/corelib/jsextensions/utilitiesextension.cpp
@@ -72,6 +72,7 @@ struct fat_arch_64 {
 
 
 #ifdef Q_OS_WIN
+#include <tools/clangclinfo.h>
 #include <tools/msvcinfo.h>
 #include <tools/vsenvironmentdetector.h>
 #endif
@@ -88,6 +89,10 @@ struct fat_arch_64 {
 namespace qbs {
 namespace Internal {
 
+class DummyLogSink : public ILogSink {
+    void doPrintMessage(LoggerLevel, const QString &, const QString &) override { }
+};
+
 class UtilitiesExtension : public QObject, QScriptable
 {
     Q_OBJECT
@@ -111,6 +116,7 @@ public:
     static QScriptValue js_msvcCompilerInfo(QScriptContext *context, QScriptEngine *engine);
     static QScriptValue js_clangClCompilerInfo(QScriptContext *context, QScriptEngine *engine);
     static QScriptValue js_installedMSVCs(QScriptContext *context, QScriptEngine *engine);
+    static QScriptValue js_installedClangCls(QScriptContext *context, QScriptEngine *engine);
 
     static QScriptValue js_versionCompare(QScriptContext *context, QScriptEngine *engine);
 
@@ -530,7 +536,11 @@ QScriptValue UtilitiesExtension::js_clangClCompilerInfo(QScriptContext *context,
                                    QStringLiteral("clangClCompilerInfo expects 4 arguments"));
 
     const QString compilerFilePath = context->argument(0).toString();
-    QString arch = context->argument(1).toString();
+    // architecture cannot be empty as vcvarsall.bat requires at least 1 arg, so fallback
+    // to host architecture if none is present
+    QString arch = !context->argument(1).isNull() && !context->argument(1).isUndefined()
+            ? context->argument(1).toString()
+            : QString::fromStdString(HostOsInfo::hostOSArchitecture());
     QString vcvarsallPath = context->argument(2).toString();
     const QString compilerLanguage = context->argumentCount() > 3
             ? context->argument(3).toString()
@@ -570,9 +580,7 @@ QScriptValue UtilitiesExtension::js_installedMSVCs(QScriptContext *context, QScr
             ? value0.toString()
             : hostArch;
 
-    class LogSink : public ILogSink {
-        void doPrintMessage(LoggerLevel, const QString &, const QString &) override { }
-    } dummySink;
+    DummyLogSink dummySink;
     Logger dummyLogger(&dummySink);
     auto msvcs = MSVC::installedCompilers(dummyLogger);
 
@@ -589,6 +597,32 @@ QScriptValue UtilitiesExtension::js_installedMSVCs(QScriptContext *context, QScr
 #endif
 }
 
+QScriptValue UtilitiesExtension::js_installedClangCls(
+        QScriptContext *context, QScriptEngine *engine)
+{
+#ifndef Q_OS_WIN
+    Q_UNUSED(engine);
+    return context->throwError(QScriptContext::UnknownError,
+        QStringLiteral("installedClangCls is not available on this platform"));
+#else
+    if (Q_UNLIKELY(context->argumentCount() != 1)) {
+        return context->throwError(QScriptContext::SyntaxError,
+                                   QStringLiteral("installedClangCls expects 1 arguments"));
+    }
+
+    const auto value0 = context->argument(0);
+    const auto path = !value0.isNull() && !value0.isUndefined() ? value0.toString() : QString();
+
+    DummyLogSink dummySink;
+    Logger dummyLogger(&dummySink);
+    auto compilers = ClangClInfo::installedCompilers({path}, dummyLogger);
+    QVariantList result;
+    for (const auto &compiler: compilers)
+        result.append(compiler.toVariantMap());
+    return engine->toScriptValue(result);
+#endif
+}
+
 QScriptValue UtilitiesExtension::js_versionCompare(QScriptContext *context, QScriptEngine *engine)
 {
     if (context->argumentCount() == 2) {
@@ -891,6 +925,8 @@ void initializeJsExtensionUtilities(QScriptValue extensionObject)
                                engine->newFunction(UtilitiesExtension::js_clangClCompilerInfo, 1));
     environmentObj.setProperty(QStringLiteral("installedMSVCs"),
                                engine->newFunction(UtilitiesExtension::js_installedMSVCs, 1));
+    environmentObj.setProperty(QStringLiteral("installedClangCls"),
+                               engine->newFunction(UtilitiesExtension::js_installedClangCls, 1));
     environmentObj.setProperty(QStringLiteral("versionCompare"),
                                engine->newFunction(UtilitiesExtension::js_versionCompare, 2));
     environmentObj.setProperty(QStringLiteral("qmlTypeInfo"),
diff --git a/src/lib/corelib/tools/clangclinfo.cpp b/src/lib/corelib/tools/clangclinfo.cpp
new file mode 100644
index 000000000..4e1022c28
--- /dev/null
+++ b/src/lib/corelib/tools/clangclinfo.cpp
@@ -0,0 +1,176 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 Ivan Komissarov (abbapoh@gmail.com)
+** Contact: http://www.qt.io/licensing
+**
+** This file is part of Qbs.
+**
+** 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 http://www.qt.io/terms-conditions. For further information
+** use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, The Qt Company gives you certain additional
+** rights.  These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#include "clangclinfo.h"
+
+#include "hostosinfo.h"
+#include "msvcinfo.h"
+#include "stlutils.h"
+
+namespace qbs {
+namespace Internal {
+
+static std::vector<MSVCInstallInfo> compatibleMsvcs(Logger &logger)
+{
+    auto msvcs = MSVCInstallInfo::installedMSVCs(logger);
+    auto filter = [](const MSVCInstallInfo &info)
+    {
+        const auto versions = info.version.split(QLatin1Char('.'));
+        if (versions.empty())
+            return true;
+        bool ok = false;
+        const int major = versions.at(0).toInt(&ok);
+        return !(ok && major >= 15); // support MSVC2017 and above
+    };
+    const auto it = std::remove_if(msvcs.begin(), msvcs.end(), filter);
+    msvcs.erase(it, msvcs.end());
+    for (const auto &msvc: msvcs) {
+        auto vcvarsallPath = msvc.findVcvarsallBat();
+        if (vcvarsallPath.isEmpty())
+            continue;
+    }
+    return msvcs;
+}
+
+static QString findCompatibleVcsarsallBat(const std::vector<MSVCInstallInfo> &msvcs)
+{
+    for (const auto &msvc: msvcs) {
+        const auto vcvarsallPath = msvc.findVcvarsallBat();
+        if (!vcvarsallPath.isEmpty())
+            return vcvarsallPath;
+    }
+    return {};
+}
+
+static QString wow6432Key()
+{
+#ifdef Q_OS_WIN64
+    return QStringLiteral("\\Wow6432Node");
+#else
+    return {};
+#endif
+}
+
+static QString getToolchainInstallPath(const QFileInfo &compiler)
+{
+    return compiler.path(); // 1 level up
+}
+
+QVariantMap ClangClInfo::toVariantMap() const
+{
+    return {
+        {QStringLiteral("toolchainInstallPath"), toolchainInstallPath},
+        {QStringLiteral("vcvarsallPath"), vcvarsallPath},
+    };
+}
+
+ClangClInfo ClangClInfo::fromCompilerFilePath(const QString &path, Logger &logger)
+{
+    const auto compilerName = QStringLiteral("clang-cl");
+    const auto vcvarsallPath = findCompatibleVcsarsallBat(compatibleMsvcs(logger));
+    if (vcvarsallPath.isEmpty()) {
+        logger.qbsWarning()
+                << Tr::tr("%1 requires installed Visual Studio 2017 or newer, but none was found.")
+                   .arg(compilerName);
+        return {};
+    }
+
+    const auto toolchainInstallPath = getToolchainInstallPath(path);
+    return {toolchainInstallPath, vcvarsallPath};
+}
+
+std::vector<ClangClInfo> ClangClInfo::installedCompilers(
+        const std::vector<QString> &extraPaths, Logger &logger)
+{
+    std::vector<QString> compilerPaths;
+    compilerPaths.reserve(extraPaths.size());
+    std::copy_if(extraPaths.begin(), extraPaths.end(),
+                 std::back_inserter(compilerPaths),
+                 [](const QString &path){ return !path.isEmpty(); });
+    const auto compilerName = HostOsInfo::appendExecutableSuffix(QStringLiteral("clang-cl"));
+
+    const QSettings registry(
+            QStringLiteral("HKEY_LOCAL_MACHINE\\SOFTWARE%1\\LLVM\\LLVM").arg(wow6432Key()),
+            QSettings::NativeFormat);
+    const auto key = QStringLiteral(".");
+    if (registry.contains(key)) {
+        const auto compilerPath = QDir::fromNativeSeparators(registry.value(key).toString())
+                + QStringLiteral("/bin/") + compilerName;
+        if (QFileInfo(compilerPath).exists())
+            compilerPaths.push_back(compilerPath);
+    }
+
+    // this branch can be useful in case user had two LLVM installations (e.g. 32bit & 64bit)
+    // but uninstalled one - in that case, registry will be empty
+    static const char * const envVarCandidates[] = {"ProgramFiles", "ProgramFiles(x86)"};
+    for (const auto &envVar : envVarCandidates) {
+        const auto value
+                = QDir::fromNativeSeparators(QString::fromLocal8Bit(qgetenv(envVar)));
+        const auto compilerPath = value + QStringLiteral("/LLVM/bin/") + compilerName;
+        if (QFileInfo(compilerPath).exists() && !contains(compilerPaths, compilerPath))
+            compilerPaths.push_back(compilerPath);
+    }
+
+    const auto msvcs = compatibleMsvcs(logger);
+    const auto vcvarsallPath = findCompatibleVcsarsallBat(msvcs);
+    if (vcvarsallPath.isEmpty()) {
+        logger.qbsWarning()
+                << Tr::tr("%1 requires installed Visual Studio 2017 or newer, but none was found.")
+                        .arg(compilerName);
+        return {};
+    }
+
+    std::vector<ClangClInfo> result;
+    result.reserve(compilerPaths.size() + msvcs.size());
+
+    for (const auto &path: compilerPaths)
+        result.push_back({getToolchainInstallPath(path), vcvarsallPath});
+
+    // If we didn't find custom LLVM installation, try to find if it's installed with Visual Studio
+    for (const auto &msvc : msvcs) {
+        const auto compilerPath = QStringLiteral("%1/VC/Tools/Llvm/bin/%2")
+                .arg(msvc.installDir, compilerName);
+        if (QFileInfo(compilerPath).exists()) {
+            const auto vcvarsallPath = msvc.findVcvarsallBat();
+            if (vcvarsallPath.isEmpty()) {
+                logger.qbsWarning()
+                        << Tr::tr("Found LLVM in %1, but vcvarsall.bat is missing.")
+                                .arg(msvc.installDir);
+            }
+
+            result.push_back({getToolchainInstallPath(compilerPath), vcvarsallPath});
+        }
+    }
+
+    return result;
+}
+
+} // namespace Internal
+} // namespace qbs
diff --git a/src/lib/corelib/tools/clangclinfo.h b/src/lib/corelib/tools/clangclinfo.h
new file mode 100644
index 000000000..76ae169f2
--- /dev/null
+++ b/src/lib/corelib/tools/clangclinfo.h
@@ -0,0 +1,61 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 Ivan Komissarov (abbapoh@gmail.com)
+** Contact: http://www.qt.io/licensing
+**
+** This file is part of Qbs.
+**
+** 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 http://www.qt.io/terms-conditions. For further information
+** use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, The Qt Company gives you certain additional
+** rights.  These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#ifndef QBS_CLANGCLINFO_H
+#define QBS_CLANGCLINFO_H
+
+#include "logging/logger.h"
+
+#include <QtCore/qstring.h>
+
+#include <vector>
+
+namespace qbs {
+namespace Internal {
+
+class ClangClInfo
+{
+public:
+    QString toolchainInstallPath;
+    QString vcvarsallPath;
+
+    bool isEmpty() const { return toolchainInstallPath.isEmpty() && vcvarsallPath.isEmpty(); }
+
+    QBS_EXPORT QVariantMap toVariantMap() const;
+
+    QBS_EXPORT static ClangClInfo fromCompilerFilePath(const QString &path, Logger &logger);
+    QBS_EXPORT static std::vector<ClangClInfo> installedCompilers(
+            const std::vector<QString> &extraPaths, qbs::Internal::Logger &logger);
+};
+
+} // namespace Internal
+} // namespace qbs
+
+#endif // QBS_CLANGCLINFO_H
diff --git a/src/lib/corelib/tools/tools.pri b/src/lib/corelib/tools/tools.pri
index 89d752671..00d87ecc7 100644
--- a/src/lib/corelib/tools/tools.pri
+++ b/src/lib/corelib/tools/tools.pri
@@ -10,6 +10,7 @@ QBS_SYSTEM_SETTINGS_DIR = $$(QBS_SYSTEM_SETTINGS_DIR)
 HEADERS += \
     $$PWD/architectures.h \
     $$PWD/buildgraphlocker.h \
+    $$PWD/clangclinfo.h \
     $$PWD/codelocation.h \
     $$PWD/commandechomode.h \
     $$PWD/dynamictypecheck.h \
@@ -68,6 +69,7 @@ HEADERS += \
 SOURCES += \
     $$PWD/architectures.cpp \
     $$PWD/buildgraphlocker.cpp \
+    $$PWD/clangclinfo.cpp \
     $$PWD/codelocation.cpp \
     $$PWD/commandechomode.cpp \
     $$PWD/error.cpp \
diff --git a/tests/auto/blackbox/tst_blackbox.cpp b/tests/auto/blackbox/tst_blackbox.cpp
index a30d57be9..a1672f4c1 100644
--- a/tests/auto/blackbox/tst_blackbox.cpp
+++ b/tests/auto/blackbox/tst_blackbox.cpp
@@ -3476,10 +3476,25 @@ void TestBlackbox::emptyProfile()
 {
     QDir::setCurrent(testDataDir + "/empty-profile");
 
+    const SettingsPtr s = settings();
+    const Profile buildProfile(profileName(), s.get());
+    const QStringList toolchain = buildProfile.value("qbs.toolchain").toStringList();
+
     QTemporaryDir tempDir;
     QbsRunParameters params;
     params.profile.clear();
     params.settingsDir = tempDir.path(); // should be no settings here
+    if (toolchain.contains(QLatin1String("clang-cl")))
+        params.arguments = QStringList{QStringLiteral("qbs.toolchainType:clang-cl")};
+    else if (toolchain.contains(QLatin1String("msvc")))
+        params.arguments = QStringList{QStringLiteral("qbs.toolchainType:msvc")};
+    else if (toolchain.contains(QLatin1String("xcode")))
+        params.arguments = QStringList{QStringLiteral("qbs.toolchainType:xcode")};
+    else if (toolchain.contains(QLatin1String("clang")))
+        params.arguments = QStringList{QStringLiteral("qbs.toolchainType:clang")};
+    else if (toolchain.contains(QLatin1String("gcc")))
+        params.arguments = QStringList{QStringLiteral("qbs.toolchainType:gcc")};
+
     QCOMPARE(runQbs(params), 0);
 }