CMake: Remove magic configuration from CMake

Get rid of magic configuration handling in the CMakeProjectManager.

* Use CMakeCache.txt as the sole source of truth, do not keep
  a shadow copy of configuration in the .user file
* Have initial CMake arguments that are easy to edit in batch
  (Fixes: QTCREATORBUG-18179) used whenever no CMakeCache.txt
  file is in the build directory. These allow for any thing that
  can be passed to CMake on the command line.
  (Fixes: QTCREATORBUG-16296)
* Ask when changes to CMake configuration were not applied
  (Fixes: QTCREATORBUG-18504)
* Run cmake with arguments effecting its configuration only when
  the CMake settings are changed in the UI, run CMake without any
  special arguments in all other cases.
* Get rid of the confusing dialog used to keep settings in sync between
  what is in CMakeCache.txt and Creator (Fixes: QTCREATORBUG-23218)

Change-Id: I26d55be7df733f084f5691ecf7d7b4352f58b8e7
Reviewed-by: Cristian Adam <cristian.adam@qt.io>

18 files changed, 432 insertions, 504 deletions

diff --git a/src/plugins/cmakeprojectmanager/builddirparameters.cpp b/src/plugins/cmakeprojectmanager/builddirparameters.cpp
index 8522029e679..82b4b91d22b 100644
--- a/src/plugins/cmakeprojectmanager/builddirparameters.cpp
+++ b/src/plugins/cmakeprojectmanager/builddirparameters.cpp
@@ -49,6 +49,17 @@ BuildDirParameters::BuildDirParameters(CMakeBuildConfiguration *bc)
 {
     QTC_ASSERT(bc, return );
 
+    const Utils::MacroExpander *expander = bc->macroExpander();
+
+    initialCMakeArguments = Utils::transform(bc->initialCMakeArguments(),
+                                             [expander](const QString &s) {
+                                                 return expander->expand(s);
+                                             });
+    extraCMakeArguments = Utils::transform(bc->extraCMakeArguments(),
+                                             [expander](const QString &s) {
+                                                 return expander->expand(s);
+                                             });
+
     const Target *t = bc->target();
     const Kit *k = t->kit();
     const Project *p = t->project();
@@ -70,23 +81,6 @@ BuildDirParameters::BuildDirParameters(CMakeBuildConfiguration *bc)
         environment.appendOrSetPath(settings->ninjaPath().toString());
 
     cmakeToolId = CMakeKitAspect::cmakeToolId(k);
-
-    auto tc = ToolChainKitAspect::cxxToolChain(k);
-    if (tc)
-        cxxToolChainId = tc->id();
-    tc = ToolChainKitAspect::cToolChain(k);
-    if (tc)
-        cToolChainId = tc->id();
-
-    expander = k->macroExpander();
-
-    configuration = bc->configurationForCMake();
-
-    generator = CMakeGeneratorKitAspect::generator(k);
-    extraGenerator = CMakeGeneratorKitAspect::extraGenerator(k);
-    platform = CMakeGeneratorKitAspect::platform(k);
-    toolset = CMakeGeneratorKitAspect::toolset(k);
-    generatorArguments = CMakeGeneratorKitAspect::generatorArguments(k);
 }
 
 bool BuildDirParameters::isValid() const
diff --git a/src/plugins/cmakeprojectmanager/builddirparameters.h b/src/plugins/cmakeprojectmanager/builddirparameters.h
index 7318ef03d86..5074a62fba3 100644
--- a/src/plugins/cmakeprojectmanager/builddirparameters.h
+++ b/src/plugins/cmakeprojectmanager/builddirparameters.h
@@ -54,21 +54,13 @@ public:
     Utils::FilePath sourceDirectory;
     Utils::FilePath buildDirectory;
     Utils::FilePath workDirectory; // either buildDirectory or a QTemporaryDirectory!
-    Utils::Environment environment;
-    Core::Id cmakeToolId;
-
-    QByteArray cxxToolChainId;
-    QByteArray cToolChainId;
 
-    Utils::MacroExpander *expander = nullptr;
+    Utils::Environment environment;
 
-    CMakeConfig configuration;
+    Core::Id cmakeToolId;
 
-    QString generator;
-    QString extraGenerator;
-    QString platform;
-    QString toolset;
-    QStringList generatorArguments;
+    QStringList initialCMakeArguments;
+    QStringList extraCMakeArguments;
 };
 
 } // namespace Internal
diff --git a/src/plugins/cmakeprojectmanager/cmakebuildconfiguration.cpp b/src/plugins/cmakeprojectmanager/cmakebuildconfiguration.cpp
index 0a28a902ff0..25ba5986e58 100644
--- a/src/plugins/cmakeprojectmanager/cmakebuildconfiguration.cpp
+++ b/src/plugins/cmakeprojectmanager/cmakebuildconfiguration.cpp
@@ -61,6 +61,41 @@ static Q_LOGGING_CATEGORY(cmakeBuildConfigurationLog, "qtc.cmake.bc", QtWarningM
 
 const char CONFIGURATION_KEY[] = "CMake.Configuration";
 
+// -----------------------------------------------------------------------------
+// Helper:
+// -----------------------------------------------------------------------------
+
+static QStringList defaultInitialCMakeArguments(const Kit *k, const QString buildType)
+{
+    // Generator:
+    QStringList initialArgs = CMakeGeneratorKitAspect::generatorArguments(k);
+
+    // CMAKE_BUILD_TYPE:
+    if (!buildType.isEmpty())
+        initialArgs.append(QString::fromLatin1("-DCMAKE_BUILD_TYPE:String=%1").arg(buildType));
+
+    // Cross-compilation settings:
+    const QString sysRoot = SysRootKitAspect::sysRoot(k).toString();
+    if (!sysRoot.isEmpty()) {
+        initialArgs.append(QString::fromLatin1("-DCMAKE_SYSROOT:PATH=%1").arg(sysRoot));
+        if (ToolChain *tc = ToolChainKitAspect::cxxToolChain(k)) {
+            const QString targetTriple = tc->originalTargetTriple();
+            initialArgs.append(
+                QString::fromLatin1("-DCMAKE_C_COMPILER_TARGET:STRING=%1").arg(targetTriple));
+            initialArgs.append(
+                QString::fromLatin1("-DCMAKE_CXX_COMPILER_TARGET:STRING=%1").arg(targetTriple));
+        }
+    }
+
+    initialArgs += CMakeConfigurationKitAspect::toArgumentsList(k);
+
+    return initialArgs;
+}
+
+// -----------------------------------------------------------------------------
+// CMakeBuildConfiguration:
+// -----------------------------------------------------------------------------
+
 CMakeBuildConfiguration::CMakeBuildConfiguration(Target *target, Core::Id id)
     : BuildConfiguration(target, id)
 {
@@ -88,41 +123,31 @@ CMakeBuildConfiguration::CMakeBuildConfiguration(Target *target, Core::Id id)
             return Utils::nullopt;
         });
 
+    addAspect<InitialCMakeArgumentsAspect>();
+
     appendInitialBuildStep(Constants::CMAKE_BUILD_STEP_ID);
     appendInitialCleanStep(Constants::CMAKE_BUILD_STEP_ID);
 
     setInitializer([this, target](const BuildInfo &info) {
-        CMakeConfig config;
-        config.append({"CMAKE_BUILD_TYPE", info.typeName.toUtf8()});
-
-        Kit *k = target->kit();
-        const QString sysRoot = SysRootKitAspect::sysRoot(k).toString();
-        if (!sysRoot.isEmpty()) {
-            config.append(CMakeConfigItem("CMAKE_SYSROOT", sysRoot.toUtf8()));
-            if (ToolChain *tc = ToolChainKitAspect::cxxToolChain(k)) {
-                const QByteArray targetTriple = tc->originalTargetTriple().toUtf8();
-                config.append(CMakeConfigItem("CMAKE_C_COMPILER_TARGET", targetTriple));
-                config.append(CMakeConfigItem("CMAKE_CXX_COMPILER_TARGET ", targetTriple));
-            }
-        }
+        const Kit *k = target->kit();
+
+        QStringList initialArgs = defaultInitialCMakeArguments(k, info.typeName);
 
+        // Android magic:
         if (DeviceTypeKitAspect::deviceTypeId(k) == Android::Constants::ANDROID_DEVICE_TYPE) {
             buildSteps()->appendStep(Android::Constants::ANDROID_BUILD_APK_ID);
             const auto &bs = buildSteps()->steps().constLast();
-            m_initialConfiguration.prepend(CMakeProjectManager::CMakeConfigItem{"ANDROID_NATIVE_API_LEVEL",
-                                                                                CMakeProjectManager::CMakeConfigItem::Type::STRING,
-                                                                                "Android native API level",
-                                                                                bs->data(Android::Constants::AndroidNdkPlatform).toString().toUtf8()});
+            initialArgs.append(
+                QString::fromLatin1("-DANDROID_NATIVE_API_LEVEL:STRING=%1")
+                    .arg(bs->data(Android::Constants::AndroidNdkPlatform).toString()));
             auto ndkLocation = bs->data(Android::Constants::NdkLocation).value<FilePath>();
-            m_initialConfiguration.prepend(CMakeProjectManager::CMakeConfigItem{"ANDROID_NDK",
-                                                                                CMakeProjectManager::CMakeConfigItem::Type::PATH,
-                                                                                "Android NDK PATH",
-                                                                                ndkLocation.toString().toUtf8()});
+            initialArgs.append(
+                QString::fromLatin1("-DANDROID_NDK:PATH=%1").arg(ndkLocation.toString()));
 
-            m_initialConfiguration.prepend(CMakeProjectManager::CMakeConfigItem{"CMAKE_TOOLCHAIN_FILE",
-                                                                                CMakeProjectManager::CMakeConfigItem::Type::PATH,
-                                                                                "Android CMake toolchain file",
-                                                                                ndkLocation.pathAppended("build/cmake/android.toolchain.cmake").toString().toUtf8()});
+            initialArgs.append(
+                QString::fromLatin1("-DCMAKE_TOOLCHAIN_FILE:PATH=%1")
+                    .arg(
+                        ndkLocation.pathAppended("build/cmake/android.toolchain.cmake").toString()));
 
             auto androidAbis = bs->data(Android::Constants::AndroidABIs).toStringList();
             QString preferredAbi;
@@ -133,29 +158,19 @@ CMakeBuildConfiguration::CMakeBuildConfiguration(Target *target, Core::Id id)
             } else {
                 preferredAbi = androidAbis.first();
             }
-            // FIXME: configmodel doesn't care about our androidAbis list...
-            m_initialConfiguration.prepend(CMakeProjectManager::CMakeConfigItem{"ANDROID_ABI",
-                                                                                CMakeProjectManager::CMakeConfigItem::Type::STRING,
-                                                                                "Android ABI",
-                                                                                preferredAbi.toLatin1(),
-                                                                                androidAbis});
+            initialArgs.append(QString::fromLatin1("-DANDROID_ABI:STRING=%1").arg(preferredAbi));
 
             QtSupport::BaseQtVersion *qt = QtSupport::QtKitAspect::qtVersion(k);
             if (qt->qtVersion() >= QtSupport::QtVersionNumber{5, 14, 0}) {
                 auto sdkLocation = bs->data(Android::Constants::SdkLocation).value<FilePath>();
-                m_initialConfiguration.prepend(CMakeProjectManager::CMakeConfigItem{"ANDROID_SDK",
-                                                                                    CMakeProjectManager::CMakeConfigItem::Type::PATH,
-                                                                                    "Android SDK PATH",
-                                                                                    sdkLocation.toString().toUtf8()});
-
+                initialArgs.append(
+                    QString::fromLatin1("-DANDROID_SDK:PATH=%1").arg(sdkLocation.toString()));
             }
 
-            m_initialConfiguration.prepend(CMakeProjectManager::CMakeConfigItem{"ANDROID_STL",
-                                                                                CMakeProjectManager::CMakeConfigItem::Type::STRING,
-                                                                                "Android STL",
-                                                                                "c++_shared"});
+            initialArgs.append(QString::fromLatin1("-DANDROID_STL:STRING=cxx_shared"));
 
-            m_initialConfiguration.prepend(CMakeProjectManager::CMakeConfigItem{"CMAKE_FIND_ROOT_PATH", "%{Qt:QT_INSTALL_PREFIX}"});
+            initialArgs.append(
+                QString::fromLatin1("-DCMAKE_FIND_ROOT_PATH:PATH=%{Qt:QT_INSTALL_PREFIX}"));
         }
 
         if (info.buildDirectory.isEmpty()) {
@@ -165,13 +180,11 @@ CMakeBuildConfiguration::CMakeBuildConfiguration(Target *target, Core::Id id)
                                                    info.buildType));
         }
 
-        setConfigurationForCMake(config);
+        setInitialCMakeArguments(initialArgs);
     });
 
     const auto qmlDebuggingAspect = addAspect<QtSupport::QmlDebuggingAspect>();
     qmlDebuggingAspect->setKit(target->kit());
-    connect(qmlDebuggingAspect, &QtSupport::QmlDebuggingAspect::changed,
-            this, &CMakeBuildConfiguration::configurationForCMakeChanged);
 }
 
 CMakeBuildConfiguration::~CMakeBuildConfiguration()
@@ -182,9 +195,6 @@ CMakeBuildConfiguration::~CMakeBuildConfiguration()
 QVariantMap CMakeBuildConfiguration::toMap() const
 {
     QVariantMap map(ProjectExplorer::BuildConfiguration::toMap());
-    const QStringList config
-            = Utils::transform(m_configurationForCMake, [](const CMakeConfigItem &i) { return i.toString(); });
-    map.insert(QLatin1String(CONFIGURATION_KEY), config);
     return map;
 }
 
@@ -198,7 +208,29 @@ bool CMakeBuildConfiguration::fromMap(const QVariantMap &map)
                                                [](const QString &v) { return CMakeConfigItem::fromString(v); }),
                               [](const CMakeConfigItem &c) { return !c.isNull(); });
 
-    setConfigurationForCMake(conf);
+    // TODO: Upgrade from Qt Creator < 4.13: Remove when no longer supported!
+    const QString buildTypeName = [this]() {
+        switch (buildType()) {
+        case Debug:
+            return QString("Debug");
+        case Profile:
+            return QString("RelWithDebInfo");
+        case Release:
+            return QString("Release");
+        case Unknown:
+        default:
+            return QString("");
+        }
+    }();
+    if (initialCMakeArguments().isEmpty()) {
+        QStringList initialArgs = defaultInitialCMakeArguments(target()->kit(),
+                                                               buildTypeName)
+                                  + Utils::transform(conf, [this](const CMakeConfigItem &i) {
+                                        return i.toArgument(macroExpander());
+                                    });
+
+        setInitialCMakeArguments(initialArgs);
+    }
 
     return true;
 }
@@ -244,54 +276,34 @@ CMakeConfig CMakeBuildConfiguration::configurationFromCMake() const
     return m_configurationFromCMake;
 }
 
-void CMakeBuildConfiguration::setConfigurationFromCMake(const CMakeConfig &config)
+QStringList CMakeBuildConfiguration::extraCMakeArguments() const
 {
-    m_configurationFromCMake = config;
+    return m_extraCMakeArguments;
 }
 
-void CMakeBuildConfiguration::setConfigurationForCMake(const QList<ConfigModel::DataItem> &items)
+QStringList CMakeBuildConfiguration::initialCMakeArguments() const
 {
-    const CMakeConfig newConfig = Utils::transform(items, [](const ConfigModel::DataItem &i) {
-        CMakeConfigItem ni;
-        ni.key = i.key.toUtf8();
-        ni.value = i.value.toUtf8();
-        ni.documentation = i.description.toUtf8();
-        ni.isAdvanced = i.isAdvanced;
-        ni.isUnset = i.isUnset;
-        ni.inCMakeCache = i.inCMakeCache;
-        ni.values = i.values;
-        switch (i.type) {
-        case CMakeProjectManager::ConfigModel::DataItem::BOOLEAN:
-            ni.type = CMakeConfigItem::BOOL;
-            break;
-        case CMakeProjectManager::ConfigModel::DataItem::FILE:
-            ni.type = CMakeConfigItem::FILEPATH;
-            break;
-        case CMakeProjectManager::ConfigModel::DataItem::DIRECTORY:
-            ni.type = CMakeConfigItem::PATH;
-            break;
-        case CMakeProjectManager::ConfigModel::DataItem::STRING:
-            ni.type = CMakeConfigItem::STRING;
-            break;
-        case CMakeProjectManager::ConfigModel::DataItem::UNKNOWN:
-        default:
-            ni.type = CMakeConfigItem::INTERNAL;
-            break;
-        }
-        return ni;
-    });
+    return aspect<InitialCMakeArgumentsAspect>()->value().split('\n', Qt::SkipEmptyParts);
+}
 
-    const CMakeConfig config = configurationForCMake() + newConfig;
-    setConfigurationForCMake(config);
+void CMakeBuildConfiguration::setExtraCMakeArguments(const QStringList &args)
+{
+    if (m_extraCMakeArguments == args)
+        return;
 
-    if (Utils::indexOf(newConfig, [](const CMakeConfigItem &item){
-            return item.key.startsWith("ANDROID_BUILD_ABI_");
-        }) != -1) {
-        // We always need to clean when we change the ANDROID_BUILD_ABI_ variables
-        BuildManager::buildLists({cleanSteps()});
-    }
+    qCDebug(cmakeBuildConfigurationLog)
+        << "Extra Args changed from" << m_extraCMakeArguments << "to" << args << "...";
+    m_extraCMakeArguments = args;
 }
 
+void CMakeBuildConfiguration::setConfigurationFromCMake(const CMakeConfig &config)
+{
+    m_configurationFromCMake = config;
+}
+
+// FIXME: Run clean steps when a setting starting with "ANDROID_BUILD_ABI_" is changed.
+// FIXME: Warn when kit settings are overridden by a project.
+
 void CMakeBuildConfiguration::clearError(ForceEnabledChanged fec)
 {
     if (!m_error.isEmpty()) {
@@ -320,37 +332,9 @@ static CMakeConfig removeDuplicates(const CMakeConfig &config)
     return result;
 }
 
-void CMakeBuildConfiguration::setConfigurationForCMake(const CMakeConfig &config)
+void CMakeBuildConfiguration::setInitialCMakeArguments(const QStringList &args)
 {
-    auto configs = removeDuplicates(config);
-    if (m_configurationForCMake.isEmpty())
-        m_configurationForCMake = removeDuplicates(m_initialConfiguration +
-            CMakeConfigurationKitAspect::configuration(target()->kit()) + configs);
-    else
-        m_configurationForCMake = configs;
-
-    const Kit *k = target()->kit();
-    CMakeConfig kitConfig = CMakeConfigurationKitAspect::configuration(k);
-    bool hasKitOverride = false;
-    foreach (const CMakeConfigItem &i, m_configurationForCMake) {
-        const QString b = CMakeConfigItem::expandedValueOf(k, i.key, kitConfig);
-        if (!b.isNull() && (i.expandedValue(k) != b || i.isUnset)) {
-            hasKitOverride = true;
-            break;
-        }
-    }
-
-    if (hasKitOverride)
-        setWarning(tr("CMake configuration set by the kit was overridden in the project."));
-    else
-        setWarning(QString());
-
-    emit configurationForCMakeChanged();
-}
-
-CMakeConfig CMakeBuildConfiguration::configurationForCMake() const
-{
-    return removeDuplicates(CMakeConfigurationKitAspect::configuration(target()->kit()) + m_configurationForCMake);
+    aspect<InitialCMakeArgumentsAspect>()->setValue(args.join('\n'));
 }
 
 void CMakeBuildConfiguration::setError(const QString &message)
@@ -491,19 +475,7 @@ BuildInfo CMakeBuildConfigurationFactory::createBuildInfo(BuildType buildType)
 
 ProjectExplorer::BuildConfiguration::BuildType CMakeBuildConfiguration::buildType() const
 {
-    QByteArray cmakeBuildTypeName;
-    QFile cmakeCache(buildDirectory().toString() + QLatin1String("/CMakeCache.txt"));
-    if (cmakeCache.open(QIODevice::ReadOnly)) {
-        while (!cmakeCache.atEnd()) {
-            QByteArray line = cmakeCache.readLine();
-            if (line.startsWith("CMAKE_BUILD_TYPE")) {
-                if (int pos = line.indexOf('='))
-                    cmakeBuildTypeName = line.mid(pos + 1).trimmed();
-                break;
-            }
-        }
-        cmakeCache.close();
-    }
+    QByteArray cmakeBuildTypeName = CMakeConfigItem::valueOf("CMAKE_BUILD_TYPE", m_configurationFromCMake);
 
     // Cover all common CMake build types
     const CMakeBuildConfigurationFactory::BuildType cmakeBuildType
@@ -516,5 +488,21 @@ BuildSystem *CMakeBuildConfiguration::buildSystem() const
     return m_buildSystem;
 }
 
+void CMakeBuildConfiguration::runCMakeWithExtraArguments()
+{
+    m_buildSystem->runCMakeWithExtraArguments();
+}
+
+// ----------------------------------------------------------------------
+// - InitialCMakeParametersAspect:
+// ----------------------------------------------------------------------
+
+InitialCMakeArgumentsAspect::InitialCMakeArgumentsAspect()
+{
+    setSettingsKey("CMake.Initial.Parameters");
+    setLabelText(tr("Initial CMake Parameters:"));
+    setDisplayStyle(TextEditDisplay);
+}
+
 } // namespace Internal
 } // namespace CMakeProjectManager
diff --git a/src/plugins/cmakeprojectmanager/cmakebuildconfiguration.h b/src/plugins/cmakeprojectmanager/cmakebuildconfiguration.h
index c3d0f06254f..24a3ca1d43c 100644
--- a/src/plugins/cmakeprojectmanager/cmakebuildconfiguration.h
+++ b/src/plugins/cmakeprojectmanager/cmakebuildconfiguration.h
@@ -28,6 +28,7 @@
 #include "cmakeconfigitem.h"
 #include "configmodel.h"
 
+#include <projectexplorer/buildaspects.h>
 #include <projectexplorer/buildconfiguration.h>
 
 namespace CMakeProjectManager {
@@ -47,9 +48,12 @@ class CMakeBuildConfiguration final : public ProjectExplorer::BuildConfiguration
     ~CMakeBuildConfiguration() final;
 
 public:
-    CMakeConfig configurationForCMake() const;
     CMakeConfig configurationFromCMake() const;
 
+    QStringList extraCMakeArguments() const;
+
+    QStringList initialCMakeArguments() const;
+
     QString error() const;
     QString warning() const;
 
@@ -61,12 +65,12 @@ public:
     void buildTarget(const QString &buildTarget);
     ProjectExplorer::BuildSystem *buildSystem() const final;
 
+    void runCMakeWithExtraArguments();
+
 signals:
     void errorOccurred(const QString &message);
     void warningOccurred(const QString &message);
 
-    void configurationForCMakeChanged();
-
 private:
     QVariantMap toMap() const override;
     BuildType buildType() const override;
@@ -79,13 +83,13 @@ private:
     void clearError(ForceEnabledChanged fec = ForceEnabledChanged::False);
 
     void setConfigurationFromCMake(const CMakeConfig &config);
-    void setConfigurationForCMake(const QList<ConfigModel::DataItem> &items);
-    void setConfigurationForCMake(const CMakeConfig &config);
+
+    void setExtraCMakeArguments(const QStringList &args);
+    void setInitialCMakeArguments(const QStringList &args);
 
     void setError(const QString &message);
     void setWarning(const QString &message);
 
-    CMakeConfig m_configurationForCMake;
     CMakeConfig m_initialConfiguration;
     QString m_error;
     QString m_warning;
@@ -93,6 +97,8 @@ private:
     CMakeConfig m_configurationFromCMake;
     CMakeBuildSystem *m_buildSystem = nullptr;
 
+    QStringList m_extraCMakeArguments;
+
     friend class CMakeBuildSettingsWidget;
     friend class CMakeBuildSystem;
     friend class CMakeProject;
@@ -120,5 +126,13 @@ private:
     friend class CMakeProjectImporter;
 };
 
+class InitialCMakeArgumentsAspect final : public ProjectExplorer::BaseStringAspect
+{
+    Q_OBJECT
+
+public:
+    InitialCMakeArgumentsAspect();
+};
+
 } // namespace Internal
 } // namespace CMakeProjectManager
diff --git a/src/plugins/cmakeprojectmanager/cmakebuildsettingswidget.cpp b/src/plugins/cmakeprojectmanager/cmakebuildsettingswidget.cpp
index c1b4d038c8d..a564bb12529 100644
--- a/src/plugins/cmakeprojectmanager/cmakebuildsettingswidget.cpp
+++ b/src/plugins/cmakeprojectmanager/cmakebuildsettingswidget.cpp
@@ -27,6 +27,7 @@
 
 #include "cmakebuildconfiguration.h"
 #include "cmakebuildsystem.h"
+#include "cmakeconfigitem.h"
 #include "cmakekitinformation.h"
 #include "configmodel.h"
 #include "configmodelitemdelegate.h"
@@ -37,6 +38,7 @@
 #include <projectexplorer/target.h>
 #include <qtsupport/qtbuildaspects.h>
 
+#include <utils/algorithm.h>
 #include <utils/categorysortfiltermodel.h>
 #include <utils/detailswidget.h>
 #include <utils/headerviewstretcher.h>
@@ -101,10 +103,13 @@ CMakeBuildSettingsWidget::CMakeBuildSettingsWidget(CMakeBuildConfiguration *bc)
     connect(buildDirAspect, &ProjectConfigurationAspect::changed, this, [this]() {
         m_configModel->flush(); // clear out config cache...;
     });
-    auto buildDirWidget = new QWidget;
-    LayoutBuilder buildDirWidgetBuilder(buildDirWidget);
-    buildDirAspect->addToLayout(buildDirWidgetBuilder);
-    mainLayout->addWidget(buildDirWidget, row, 0, 1, 2);
+    auto initialCMakeAspect = bc->aspect<InitialCMakeArgumentsAspect>();
+    auto aspectWidget = new QWidget;
+    LayoutBuilder aspectWidgetBuilder(aspectWidget);
+    buildDirAspect->addToLayout(aspectWidgetBuilder);
+    aspectWidgetBuilder.startNewRow();
+    initialCMakeAspect->addToLayout(aspectWidgetBuilder);
+    mainLayout->addWidget(aspectWidget, row, 0, 1, 2);
     ++row;
 
     auto qmlDebugAspect = bc->aspect<QtSupport::QmlDebuggingAspect>();
@@ -270,9 +275,10 @@ CMakeBuildSettingsWidget::CMakeBuildSettingsWidget(CMakeBuildConfiguration *bc)
             m_configTextFilterModel, &QSortFilterProxyModel::setFilterFixedString);
 
     connect(m_resetButton, &QPushButton::clicked, m_configModel, &ConfigModel::resetAllChanges);
-    connect(m_reconfigureButton, &QPushButton::clicked, this, [this]() {
-        m_buildConfiguration->setConfigurationForCMake(m_configModel->configurationForCMake());
-    });
+    connect(m_reconfigureButton,
+            &QPushButton::clicked,
+            m_buildConfiguration,
+            &CMakeBuildConfiguration::runCMakeWithExtraArguments);
     connect(m_unsetButton, &QPushButton::clicked, this, [this]() {
         m_configModel->toggleUnsetFlag(mapToSource(m_configView, m_configView->currentIndex()));
     });
@@ -312,10 +318,7 @@ CMakeBuildSettingsWidget::CMakeBuildSettingsWidget(CMakeBuildConfiguration *bc)
     connect(m_buildConfiguration, &CMakeBuildConfiguration::enabledChanged,
             this, [this]() {
         setError(m_buildConfiguration->disabledReason());
-        setConfigurationForCMake();
     });
-    connect(m_buildConfiguration, &CMakeBuildConfiguration::configurationForCMakeChanged,
-            this, [this]() { setConfigurationForCMake(); });
 
     updateSelection(QModelIndex(), QModelIndex());
 }
@@ -338,6 +341,42 @@ void CMakeBuildSettingsWidget::updateButtonState()
     const bool hasChanges = m_configModel->hasChanges();
     m_resetButton->setEnabled(hasChanges && !isParsing);
     m_reconfigureButton->setEnabled((hasChanges || m_configModel->hasCMakeChanges()) && !isParsing);
+
+    // Update extra data in buildconfiguration
+    const QList<ConfigModel::DataItem> changes = m_configModel->configurationForCMake();
+
+    const CMakeConfig configChanges = Utils::transform(changes, [](const ConfigModel::DataItem &i) {
+        CMakeConfigItem ni;
+        ni.key = i.key.toUtf8();
+        ni.value = i.value.toUtf8();
+        ni.documentation = i.description.toUtf8();
+        ni.isAdvanced = i.isAdvanced;
+        ni.isUnset = i.isUnset;
+        ni.inCMakeCache = i.inCMakeCache;
+        ni.values = i.values;
+        switch (i.type) {
+        case CMakeProjectManager::ConfigModel::DataItem::BOOLEAN:
+            ni.type = CMakeConfigItem::BOOL;
+            break;
+        case CMakeProjectManager::ConfigModel::DataItem::FILE:
+            ni.type = CMakeConfigItem::FILEPATH;
+            break;
+        case CMakeProjectManager::ConfigModel::DataItem::DIRECTORY:
+            ni.type = CMakeConfigItem::PATH;
+            break;
+        case CMakeProjectManager::ConfigModel::DataItem::STRING:
+            ni.type = CMakeConfigItem::STRING;
+            break;
+        case CMakeProjectManager::ConfigModel::DataItem::UNKNOWN:
+        default:
+            ni.type = CMakeConfigItem::INTERNAL;
+            break;
+        }
+        return ni;
+    });
+
+    m_buildConfiguration->setExtraCMakeArguments(
+        Utils::transform(configChanges, [](const CMakeConfigItem &i) { return i.toArgument(); }));
 }
 
 void CMakeBuildSettingsWidget::updateAdvancedCheckBox()
@@ -371,49 +410,39 @@ void CMakeBuildSettingsWidget::handleQmlDebugCxxFlags()
     const auto aspect = m_buildConfiguration->aspect<QtSupport::QmlDebuggingAspect>();
     const bool enable = aspect->setting() == TriState::Enabled;
 
-    CMakeConfig changedConfig = m_buildConfiguration->configurationForCMake();
     const CMakeConfig configList = m_buildConfiguration->configurationFromCMake();
     const QByteArrayList cxxFlags{"CMAKE_CXX_FLAGS", "CMAKE_CXX_FLAGS_DEBUG",
                                   "CMAKE_CXX_FLAGS_RELWITHDEBINFO"};
     const QByteArray qmlDebug("-DQT_QML_DEBUG");
 
-    for (CMakeConfigItem item : configList) {
-        CMakeConfigItem it(item);
+    CMakeConfig changedConfig;
+
+    for (const CMakeConfigItem &item : configList) {
+        if (!cxxFlags.contains(item.key))
+            continue;
 
-        if (cxxFlags.contains(it.key)) {
-            if (enable) {
-                if (!it.value.contains(qmlDebug)) {
-                    it.value = it.value.append(' ').append(qmlDebug);
-                    changed = true;
-                }
-            } else {
-                int index = it.value.indexOf(qmlDebug);
-                if (index != -1) {
-                    it.value.remove(index, qmlDebug.length());
-                    changed = true;
-                }
+        CMakeConfigItem it(item);
+        if (enable) {
+            if (!it.value.contains(qmlDebug)) {
+                it.value = it.value.append(' ').append(qmlDebug);
+                changed = true;
+            }
+        } else {
+            int index = it.value.indexOf(qmlDebug);
+            if (index != -1) {
+                it.value.remove(index, qmlDebug.length());
+                changed = true;
             }
-            it.value = it.value.trimmed();
-            changedConfig.append(it);
         }
+        it.value = it.value.trimmed();
+        changedConfig.append(it);
     }
 
-    if (!changed)
-        return;
-
-    m_buildConfiguration->setConfigurationForCMake(changedConfig);
-}
-
-void CMakeBuildSettingsWidget::setConfigurationForCMake()
-{
-    QHash<QString, QString> config;
-    const CMakeConfig configList = m_buildConfiguration->configurationForCMake();
-    for (const CMakeConfigItem &i : configList) {
-        config.insert(QString::fromUtf8(i.key),
-                      CMakeConfigItem::expandedValueOf(m_buildConfiguration->target()->kit(),
-                                                       i.key, configList));
+    if (changed) {
+        m_buildConfiguration->setExtraCMakeArguments(
+            Utils::transform(changedConfig,
+                             [](const CMakeConfigItem &i) { return i.toArgument(); }));
     }
-    m_configModel->setConfigurationForCMake(config);
 }
 
 void CMakeBuildSettingsWidget::updateSelection(const QModelIndex &current, const QModelIndex &previous)
diff --git a/src/plugins/cmakeprojectmanager/cmakebuildsettingswidget.h b/src/plugins/cmakeprojectmanager/cmakebuildsettingswidget.h
index 1014d2f6747..49f945230b9 100644
--- a/src/plugins/cmakeprojectmanager/cmakebuildsettingswidget.h
+++ b/src/plugins/cmakeprojectmanager/cmakebuildsettingswidget.h
@@ -68,7 +68,6 @@ private:
     void updateFromKit();
     void handleQmlDebugCxxFlags();
 
-    void setConfigurationForCMake();
     void updateSelection(const QModelIndex &current, const QModelIndex &previous);
     QAction *createForceAction(int type, const QModelIndex &idx);
 
diff --git a/src/plugins/cmakeprojectmanager/cmakebuildsystem.cpp b/src/plugins/cmakeprojectmanager/cmakebuildsystem.cpp
index 48ef90f682a..4501ee7e3af 100644
--- a/src/plugins/cmakeprojectmanager/cmakebuildsystem.cpp
+++ b/src/plugins/cmakeprojectmanager/cmakebuildsystem.cpp
@@ -224,6 +224,7 @@ void CMakeBuildSystem::triggerParsing()
         // is selected while this here is already running.
 
         // Stop old parse run and keep that ParseGuard!
+        qCDebug(cmakeBuildSystemLog) << "Stopping current parsing run!";
         stopParsingAndClearState();
     } else {
         // Use new ParseGuard
@@ -233,10 +234,15 @@ void CMakeBuildSystem::triggerParsing()
 
     qCDebug(cmakeBuildSystemLog) << "ParseGuard acquired.";
 
-    if (m_allFiles.isEmpty())
+    if (m_allFiles.isEmpty()) {
+        qCDebug(cmakeBuildSystemLog)
+            << "No treescanner information available, forcing treescanner run.";
         updateReparseParameters(REPARSE_SCAN);
+    }
+
+    int reparseParameters = takeReparseParameters();
 
-    m_waitingForScan = (m_reparseParameters | REPARSE_SCAN) != 0;
+    m_waitingForScan = (reparseParameters & REPARSE_SCAN) != 0;
     m_waitingForParse = true;
     m_combinedScanAndParseResult = true;
 
@@ -254,30 +260,31 @@ void CMakeBuildSystem::triggerParsing()
 
     TaskHub::clearTasks(ProjectExplorer::Constants::TASK_CATEGORY_BUILDSYSTEM);
 
-    int reparseParameters = takeReparseParameters();
-
     qCDebug(cmakeBuildSystemLog) << "Parse called with flags:"
                                  << reparseParametersString(reparseParameters);
 
     const QString cache = m_parameters.workDirectory.pathAppended("CMakeCache.txt").toString();
     if (!QFileInfo::exists(cache)) {
-        reparseParameters |= REPARSE_FORCE_CONFIGURATION | REPARSE_FORCE_CMAKE_RUN;
+        reparseParameters |= REPARSE_FORCE_INITIAL_CONFIGURATION | REPARSE_FORCE_CMAKE_RUN;
         qCDebug(cmakeBuildSystemLog)
             << "No" << cache
             << "file found, new flags:" << reparseParametersString(reparseParameters);
-    } else if (reparseParameters & REPARSE_CHECK_CONFIGURATION) {
-        if (checkConfiguration()) {
-            reparseParameters |= REPARSE_FORCE_CONFIGURATION | REPARSE_FORCE_CMAKE_RUN;
-            qCDebug(cmakeBuildSystemLog) << "Config check triggered flags change:"
-                                         << reparseParametersString(reparseParameters);
-        }
     }
 
-    writeConfigurationIntoBuildDirectory(m_parameters.expander);
+    if ((0 == (reparseParameters & REPARSE_FORCE_EXTRA_CONFIGURATION))
+        && !m_parameters.extraCMakeArguments.isEmpty()) {
+        if (mustApplyExtraArguments())
+            reparseParameters |= REPARSE_FORCE_CMAKE_RUN | REPARSE_FORCE_EXTRA_CONFIGURATION;
+    }
+
+    // Do not add extra args when doing initial configuration
+    if (0 != (reparseParameters & REPARSE_FORCE_INITIAL_CONFIGURATION))
+        reparseParameters = reparseParameters ^ REPARSE_FORCE_EXTRA_CONFIGURATION;
 
     qCDebug(cmakeBuildSystemLog) << "Asking reader to parse";
     m_reader.parse(reparseParameters & REPARSE_FORCE_CMAKE_RUN,
-                   reparseParameters & REPARSE_FORCE_CONFIGURATION);
+                   reparseParameters & REPARSE_FORCE_INITIAL_CONFIGURATION,
+                   reparseParameters & REPARSE_FORCE_EXTRA_CONFIGURATION);
 }
 
 bool CMakeBuildSystem::supportsAction(Node *context, ProjectAction action, const Node *node) const
@@ -350,10 +357,8 @@ QString CMakeBuildSystem::reparseParametersString(int reparseFlags)
             result += " URGENT";
         if (reparseFlags & REPARSE_FORCE_CMAKE_RUN)
             result += " FORCE_CMAKE_RUN";
-        if (reparseFlags & REPARSE_FORCE_CONFIGURATION)
+        if (reparseFlags & REPARSE_FORCE_INITIAL_CONFIGURATION)
             result += " FORCE_CONFIG";
-        if (reparseFlags & REPARSE_CHECK_CONFIGURATION)
-            result += " CHECK_CONFIG";
         if (reparseFlags & REPARSE_SCAN)
             result += " SCAN";
     }
@@ -363,7 +368,8 @@ QString CMakeBuildSystem::reparseParametersString(int reparseFlags)
 void CMakeBuildSystem::setParametersAndRequestParse(const BuildDirParameters &parameters,
                                                     const int reparseParameters)
 {
-    qCDebug(cmakeBuildSystemLog) << "setting parameters and requesting reparse";
+    qCDebug(cmakeBuildSystemLog) << "setting parameters and requesting reparse"
+                                 << reparseParametersString(reparseParameters);
     if (!parameters.cmakeTool()) {
         TaskHub::addTask(
             BuildSystemTask(Task::Error,
@@ -387,42 +393,42 @@ void CMakeBuildSystem::setParametersAndRequestParse(const BuildDirParameters &pa
     }
 }
 
-void CMakeBuildSystem::writeConfigurationIntoBuildDirectory(const Utils::MacroExpander *expander)
+bool CMakeBuildSystem::mustApplyExtraArguments() const
 {
-    QTC_ASSERT(expander, return );
-
-    const FilePath buildDir = workDirectory(m_parameters);
-    QTC_ASSERT(buildDir.exists(), return );
-
-    const FilePath settingsFile = buildDir.pathAppended("qtcsettings.cmake");
-
-    QByteArray contents;
-    contents.append("# This file is managed by Qt Creator, do not edit!\n\n");
-    contents.append(
-        transform(m_parameters.configuration,
-                  [expander](const CMakeConfigItem &item) { return item.toCMakeSetLine(expander); })
-            .join('\n')
-            .toUtf8());
+    if (m_parameters.extraCMakeArguments.isEmpty())
+        return false;
 
-    QFile file(settingsFile.toString());
-    QTC_ASSERT(file.open(QFile::WriteOnly | QFile::Truncate), return );
-    file.write(contents);
+    auto answer = QMessageBox::question(Core::ICore::mainWindow(),
+                                        tr("Apply configuration changes?"),
+                                        tr("Run CMake with \"%1\"?")
+                                            .arg(m_parameters.extraCMakeArguments.join(" ")),
+                                        QMessageBox::Apply | QMessageBox::Discard,
+                                        QMessageBox::Apply);
+    return answer == QMessageBox::Apply;
 }
 
 void CMakeBuildSystem::runCMake()
 {
     BuildDirParameters parameters(cmakeBuildConfiguration());
     qCDebug(cmakeBuildSystemLog) << "Requesting parse due \"Run CMake\" command";
-    setParametersAndRequestParse(parameters,
-                                 REPARSE_CHECK_CONFIGURATION | REPARSE_FORCE_CMAKE_RUN
-                                     | REPARSE_URGENT);
+    setParametersAndRequestParse(parameters, REPARSE_FORCE_CMAKE_RUN | REPARSE_URGENT);
 }
 
 void CMakeBuildSystem::runCMakeAndScanProjectTree()
 {
     BuildDirParameters parameters(cmakeBuildConfiguration());
     qCDebug(cmakeBuildSystemLog) << "Requesting parse due to \"Rescan Project\" command";
-    setParametersAndRequestParse(parameters, REPARSE_CHECK_CONFIGURATION | REPARSE_SCAN);
+    setParametersAndRequestParse(parameters,
+                                 REPARSE_FORCE_CMAKE_RUN | REPARSE_SCAN | REPARSE_URGENT);
+}
+
+void CMakeBuildSystem::runCMakeWithExtraArguments()
+{
+    BuildDirParameters parameters(cmakeBuildConfiguration());
+    qCDebug(cmakeBuildSystemLog) << "Requesting parse due to \"Rescan Project\" command";
+    setParametersAndRequestParse(parameters,
+                                 REPARSE_FORCE_CMAKE_RUN | REPARSE_FORCE_EXTRA_CONFIGURATION
+                                     | REPARSE_URGENT);
 }
 
 void CMakeBuildSystem::buildCMakeTarget(const QString &buildTarget)
@@ -445,20 +451,39 @@ void CMakeBuildSystem::handleTreeScanningFinished()
 
 bool CMakeBuildSystem::persistCMakeState()
 {
-    QTC_ASSERT(m_parameters.isValid(), return false);
+    BuildDirParameters parameters(cmakeBuildConfiguration());
+    QTC_ASSERT(parameters.isValid(), return false);
+
+    parameters.workDirectory = workDirectory(parameters);
+
+    int reparseFlags = REPARSE_DEFAULT;
+    qCDebug(cmakeBuildSystemLog) << "Checking whether build system needs to be persisted:"
+                                 << "workdir:" << parameters.workDirectory
+                                 << "buildDir:" << parameters.buildDirectory
+                                 << "Has extraargs:" << !parameters.extraCMakeArguments.isEmpty()
+                                 << "must apply extra Args:"
+                                 << mustApplyExtraArguments();
+
+    if (parameters.workDirectory == parameters.buildDirectory
+        && !parameters.extraCMakeArguments.isEmpty() && mustApplyExtraArguments()) {
+        reparseFlags = REPARSE_FORCE_EXTRA_CONFIGURATION;
+        qCDebug(cmakeBuildSystemLog) << "   -> must run CMake with extra arguments.";
+    }
+    if (parameters.workDirectory != parameters.buildDirectory
+        && buildConfiguration()->createBuildDirectory()) {
+        reparseFlags = REPARSE_FORCE_INITIAL_CONFIGURATION;
+        qCDebug(cmakeBuildSystemLog) << "   -> must run CMake with initial arguments.";
+    }
 
-    if (m_parameters.workDirectory == m_parameters.buildDirectory)
+    if (reparseFlags == REPARSE_DEFAULT)
         return false;
 
-    if (!buildConfiguration()->createBuildDirectory())
-        return false;
+    if (reparseFlags == REPARSE_FORCE_INITIAL_CONFIGURATION)
+        parameters.workDirectory.clear();
 
-    BuildDirParameters newParameters = m_parameters;
-    newParameters.workDirectory.clear();
-    qCDebug(cmakeBuildSystemLog) << "Requesting parse due to persisting CMake State";
-    setParametersAndRequestParse(newParameters,
-                                 REPARSE_URGENT | REPARSE_FORCE_CMAKE_RUN
-                                     | REPARSE_FORCE_CONFIGURATION | REPARSE_CHECK_CONFIGURATION);
+    qCDebug(cmakeBuildSystemLog) << "Requesting parse to persist CMake State";
+    setParametersAndRequestParse(parameters,
+                                 REPARSE_URGENT | REPARSE_FORCE_CMAKE_RUN | reparseFlags);
     return true;
 }
 
@@ -685,22 +710,20 @@ void CMakeBuildSystem::wireUpConnections(const Project *p)
     connect(KitManager::instance(), &KitManager::kitUpdated, this, [this](Kit *k) {
         if (k != kit())
             return; // not for us...
-        // Build configuration has not changed, but Kit settings might have:
-        // reparse and check the configuration, independent of whether the reader has changed
+        // FIXME: This is no longer correct: QtC now needs to update the initial parameters
+        // FIXME: and then ask to reconfigure.
         qCDebug(cmakeBuildSystemLog) << "Requesting parse due to kit being updated";
         setParametersAndRequestParse(BuildDirParameters(cmakeBuildConfiguration()),
-                                     CMakeBuildSystem::REPARSE_CHECK_CONFIGURATION);
+                                     CMakeBuildSystem::REPARSE_FORCE_CMAKE_RUN);
     });
 
     // Became active/inactive:
     connect(project(), &Project::activeTargetChanged, this, [this](Target *t) {
         if (t == target()) {
-            // Build configuration has switched:
-            // * Check configuration if reader changes due to it not existing yet:-)
-            // * run cmake without configuration arguments if the reader stays
+            // Build configuration has changed along with the target:
             qCDebug(cmakeBuildSystemLog) << "Requesting parse due to active target changed";
             setParametersAndRequestParse(BuildDirParameters(cmakeBuildConfiguration()),
-                                         CMakeBuildSystem::REPARSE_CHECK_CONFIGURATION);
+                                         CMakeBuildSystem::REPARSE_DEFAULT);
         } else {
             stopParsingAndClearState();
         }
@@ -708,12 +731,10 @@ void CMakeBuildSystem::wireUpConnections(const Project *p)
     connect(target(), &Target::activeBuildConfigurationChanged, this, [this](BuildConfiguration *bc) {
         if (cmakeBuildConfiguration()->isActive()) {
             if (cmakeBuildConfiguration() == bc) {
-                // Build configuration has switched:
-                // * Check configuration if reader changes due to it not existing yet:-)
-                // * run cmake without configuration arguments if the reader stays
+                // Build configuration has changed:
                 qCDebug(cmakeBuildSystemLog) << "Requesting parse due to active BC changed";
                 setParametersAndRequestParse(BuildDirParameters(cmakeBuildConfiguration()),
-                                             CMakeBuildSystem::REPARSE_CHECK_CONFIGURATION);
+                                             CMakeBuildSystem::REPARSE_DEFAULT);
             } else {
                 stopParsingAndClearState();
             }
@@ -723,40 +744,22 @@ void CMakeBuildSystem::wireUpConnections(const Project *p)
     // BuildConfiguration changed:
     connect(cmakeBuildConfiguration(), &CMakeBuildConfiguration::environmentChanged, this, [this]() {
         if (cmakeBuildConfiguration()->isActive()) {
-            // The environment on our BC has changed:
-            // * Error out if the reader updates, cannot happen since all BCs share a target/kit.
-            // * run cmake without configuration arguments if the reader stays
+            // The environment on our BC has changed, force CMake run to catch up with possible changes
             qCDebug(cmakeBuildSystemLog) << "Requesting parse due to environment change";
             setParametersAndRequestParse(BuildDirParameters(cmakeBuildConfiguration()),
-                                         CMakeBuildSystem::REPARSE_CHECK_CONFIGURATION);
+                                         CMakeBuildSystem::REPARSE_FORCE_CMAKE_RUN);
         }
     });
     connect(cmakeBuildConfiguration(), &CMakeBuildConfiguration::buildDirectoryChanged, this, [this]() {
         if (cmakeBuildConfiguration()->isActive()) {
             // The build directory of our BC has changed:
-            // * Error out if the reader updates, cannot happen since all BCs share a target/kit.
-            // * run cmake without configuration arguments if the reader stays
-            //   If no configuration exists, then the arguments will get added automatically by
-            //   the reader.
+            // Run with initial arguments!
             qCDebug(cmakeBuildSystemLog) << "Requesting parse due to build directory change";
             setParametersAndRequestParse(BuildDirParameters(cmakeBuildConfiguration()),
-                                         CMakeBuildSystem::REPARSE_CHECK_CONFIGURATION);
+                                         CMakeBuildSystem::REPARSE_FORCE_INITIAL_CONFIGURATION
+                                             | CMakeBuildSystem::REPARSE_FORCE_CMAKE_RUN);
         }
     });
-    connect(cmakeBuildConfiguration(),
-            &CMakeBuildConfiguration::configurationForCMakeChanged,
-            this,
-            [this]() {
-                if (cmakeBuildConfiguration()->isActive()) {
-                    // The CMake configuration has changed on our BC:
-                    // * Error out if the reader updates, cannot happen since all BCs share a target/kit.
-                    // * run cmake with configuration arguments if the reader stays
-                    qCDebug(cmakeBuildSystemLog)
-                        << "Requesting parse due to cmake configuration change";
-                    setParametersAndRequestParse(BuildDirParameters(cmakeBuildConfiguration()),
-                                                 CMakeBuildSystem::REPARSE_FORCE_CONFIGURATION);
-                }
-            });
 
     connect(project(), &Project::projectFileIsDirty, this, [this]() {
         if (cmakeBuildConfiguration()->isActive() && !isParsing()) {
@@ -770,9 +773,11 @@ void CMakeBuildSystem::wireUpConnections(const Project *p)
     });
 
     // Force initial parsing run:
-    if (cmakeBuildConfiguration()->isActive())
+    if (cmakeBuildConfiguration()->isActive()) {
+        qCDebug(cmakeBuildSystemLog) << "Initial run:";
         setParametersAndRequestParse(BuildDirParameters(cmakeBuildConfiguration()),
-                                     CMakeBuildSystem::REPARSE_CHECK_CONFIGURATION);
+                                     CMakeBuildSystem::REPARSE_DEFAULT);
+    }
 }
 
 FilePath CMakeBuildSystem::workDirectory(const BuildDirParameters &parameters)
@@ -824,8 +829,7 @@ void CMakeBuildSystem::becameDirty()
     if (!tool->isAutoRun())
         return;
 
-    setParametersAndRequestParse(BuildDirParameters(cmakeBuildConfiguration()),
-                                 REPARSE_CHECK_CONFIGURATION | REPARSE_SCAN);
+    setParametersAndRequestParse(BuildDirParameters(cmakeBuildConfiguration()), REPARSE_SCAN);
 }
 
 void CMakeBuildSystem::updateReparseParameters(const int parameters)
@@ -840,149 +844,6 @@ int CMakeBuildSystem::takeReparseParameters()
     return result;
 }
 
-bool CMakeBuildSystem::hasConfigChanged()
-{
-    checkConfiguration();
-
-    const QByteArray GENERATOR_KEY = "CMAKE_GENERATOR";
-    const QByteArray EXTRA_GENERATOR_KEY = "CMAKE_EXTRA_GENERATOR";
-    const QByteArray CMAKE_COMMAND_KEY = "CMAKE_COMMAND";
-    const QByteArray CMAKE_C_COMPILER_KEY = "CMAKE_C_COMPILER";
-    const QByteArray CMAKE_CXX_COMPILER_KEY = "CMAKE_CXX_COMPILER";
-
-    const QByteArrayList criticalKeys = {GENERATOR_KEY,
-                                         CMAKE_COMMAND_KEY,
-                                         CMAKE_C_COMPILER_KEY,
-                                         CMAKE_CXX_COMPILER_KEY};
-
-    QString errorMessage;
-    const CMakeConfig currentConfig = cmakeBuildConfiguration()->configurationFromCMake();
-    if (!errorMessage.isEmpty())
-        return false;
-
-    const CMakeTool *tool = m_parameters.cmakeTool();
-    QTC_ASSERT(tool,
-               return false); // No cmake... we should not have ended up here in the first place
-    const QString extraKitGenerator = m_parameters.extraGenerator;
-    const QString mainKitGenerator = m_parameters.generator;
-    CMakeConfig targetConfig = m_parameters.configuration;
-    targetConfig.append(CMakeConfigItem(GENERATOR_KEY,
-                                        CMakeConfigItem::INTERNAL,
-                                        QByteArray(),
-                                        mainKitGenerator.toUtf8()));
-    if (!extraKitGenerator.isEmpty())
-        targetConfig.append(CMakeConfigItem(EXTRA_GENERATOR_KEY,
-                                            CMakeConfigItem::INTERNAL,
-                                            QByteArray(),
-                                            extraKitGenerator.toUtf8()));
-    targetConfig.append(CMakeConfigItem(CMAKE_COMMAND_KEY,
-                                        CMakeConfigItem::INTERNAL,
-                                        QByteArray(),
-                                        tool->cmakeExecutable().toUserOutput().toUtf8()));
-    Utils::sort(targetConfig, CMakeConfigItem::sortOperator());
-
-    bool mustReparse = false;
-    auto ccit = currentConfig.constBegin();
-    auto kcit = targetConfig.constBegin();
-
-    while (ccit != currentConfig.constEnd() && kcit != targetConfig.constEnd()) {
-        if (ccit->key == kcit->key) {
-            if (ccit->value != kcit->value) {
-                if (criticalKeys.contains(kcit->key)) {
-                    clearCMakeCache();
-                    return false; // no need to trigger a new reader, clearCache will do that
-                }
-                mustReparse = true;
-            }
-            ++ccit;
-            ++kcit;
-        } else {
-            if (ccit->key < kcit->key) {
-                ++ccit;
-            } else {
-                ++kcit;
-                mustReparse = true;
-            }
-        }
-    }
-
-    // If we have keys that do not exist yet, then reparse.
-    //
-    // The critical keys *must* be set in cmake configuration, so those were already
-    // handled above.
-    return mustReparse || kcit != targetConfig.constEnd();
-}
-
-bool CMakeBuildSystem::checkConfiguration()
-{
-    if (m_parameters.workDirectory
-        != m_parameters.buildDirectory) // always throw away changes in the tmpdir!
-        return false;
-
-    const CMakeConfig cache = cmakeBuildConfiguration()->configurationFromCMake();
-    if (cache.isEmpty())
-        return false; // No cache file yet.
-
-    CMakeConfig newConfig;
-    QHash<QString, QPair<QString, QString>> changedKeys;
-    foreach (const CMakeConfigItem &projectItem, m_parameters.configuration) {
-        const QString projectKey = QString::fromUtf8(projectItem.key);
-        const QString projectValue = projectItem.expandedValue(m_parameters.expander);
-        const CMakeConfigItem &cmakeItem = Utils::findOrDefault(cache,
-                                                                [&projectItem](
-                                                                    const CMakeConfigItem &i) {
-                                                                    return i.key == projectItem.key;
-                                                                });
-        const QString iCacheValue = QString::fromUtf8(cmakeItem.value);
-        if (cmakeItem.isNull()) {
-            changedKeys.insert(projectKey, qMakePair(tr("<removed>"), projectValue));
-        } else if (iCacheValue != projectValue) {
-            changedKeys.insert(projectKey, qMakePair(iCacheValue, projectValue));
-            newConfig.append(cmakeItem);
-        } else {
-            newConfig.append(projectItem);
-        }
-    }
-
-    if (!changedKeys.isEmpty()) {
-        QStringList keyList = changedKeys.keys();
-        Utils::sort(keyList);
-        QString table = QString::fromLatin1("<table><tr><th>%1</th><th>%2</th><th>%3</th></tr>")
-                            .arg(tr("Key"))
-                            .arg(tr("%1 Project").arg(Core::Constants::IDE_DISPLAY_NAME))
-                            .arg(tr("Changed value"));
-        foreach (const QString &k, keyList) {
-            const QPair<QString, QString> data = changedKeys.value(k);
-            table += QString::fromLatin1("\n<tr><td>%1</td><td>%2</td><td>%3</td></tr>")
-                         .arg(k)
-                         .arg(data.second.toHtmlEscaped())
-                         .arg(data.first.toHtmlEscaped());
-        }
-        table += QLatin1String("\n</table>");
-
-        QPointer<QMessageBox> box = new QMessageBox(Core::ICore::dialogParent());
-        box->setText(tr("The project has been changed outside of %1.")
-                         .arg(Core::Constants::IDE_DISPLAY_NAME));
-        box->setInformativeText(table);
-        auto *defaultButton = box->addButton(tr("Discard External Changes"),
-                                             QMessageBox::RejectRole);
-        auto *applyButton = box->addButton(tr("Adapt %1 Project to Changes")
-                                               .arg(Core::Constants::IDE_DISPLAY_NAME),
-                                           QMessageBox::ApplyRole);
-        box->setDefaultButton(defaultButton);
-
-        box->exec();
-        if (box->clickedButton() == applyButton) {
-            m_parameters.configuration = newConfig;
-            QSignalBlocker blocker(buildConfiguration());
-            cmakeBuildConfiguration()->setConfigurationForCMake(newConfig);
-            return false;
-        } else if (box->clickedButton() == defaultButton)
-            return true;
-    }
-    return false;
-}
-
 CMakeBuildConfiguration *CMakeBuildSystem::cmakeBuildConfiguration() const
 {
     return static_cast<CMakeBuildConfiguration *>(BuildSystem::buildConfiguration());
diff --git a/src/plugins/cmakeprojectmanager/cmakebuildsystem.h b/src/plugins/cmakeprojectmanager/cmakebuildsystem.h
index 5ada71513c6..86d77d7a7d7 100644
--- a/src/plugins/cmakeprojectmanager/cmakebuildsystem.h
+++ b/src/plugins/cmakeprojectmanager/cmakebuildsystem.h
@@ -63,7 +63,7 @@ public:
 
     bool supportsAction(ProjectExplorer::Node *context,
                         ProjectExplorer::ProjectAction action,
-                        const ProjectExplorer::Node *node) const override;
+                        const ProjectExplorer::Node *node) const final;
 
     bool addFiles(ProjectExplorer::Node *context,
                   const QStringList &filePaths, QStringList *) final;
@@ -73,6 +73,7 @@ public:
     // Actions:
     void runCMake();
     void runCMakeAndScanProjectTree();
+    void runCMakeWithExtraArguments();
 
     bool persistCMakeState();
     void clearCMakeCache();
@@ -95,19 +96,20 @@ public:
 private:
     // Actually ask for parsing:
     enum ReparseParameters {
-        REPARSE_DEFAULT = 0,                    // Nothing special:-)
-        REPARSE_FORCE_CMAKE_RUN = (1 << 0),     // Force cmake to run
-        REPARSE_FORCE_CONFIGURATION = (1 << 1), // Force configuration arguments to cmake
-        REPARSE_CHECK_CONFIGURATION
-        = (1 << 2), // Check for on-disk config and QtC config diff // FIXME: Remove this!
-        REPARSE_SCAN = (1 << 3),   // Run filesystem scan
-        REPARSE_URGENT = (1 << 4), // Do not delay the parser run by 1s
+        REPARSE_DEFAULT = 0, // Nothing special:-)
+        REPARSE_FORCE_CMAKE_RUN
+        = (1 << 0), // Force cmake to run, apply extraCMakeArguments if non-empty
+        REPARSE_FORCE_INITIAL_CONFIGURATION
+        = (1 << 1), // Force initial configuration arguments to cmake
+        REPARSE_FORCE_EXTRA_CONFIGURATION = (1 << 2), // Force extra configuration arguments to cmake
+        REPARSE_SCAN = (1 << 3),                      // Run filesystem scan
+        REPARSE_URGENT = (1 << 4),                    // Do not delay the parser run by 1s
     };
     QString reparseParametersString(int reparseFlags);
     void setParametersAndRequestParse(const BuildDirParameters &parameters,
                                       const int reparseParameters);
 
-    void writeConfigurationIntoBuildDirectory(const Utils::MacroExpander *expander);
+    bool mustApplyExtraArguments() const;
 
     // State handling:
     // Parser states:
@@ -155,12 +157,9 @@ private:
     QList<ProjectExplorer::ExtraCompiler *> m_extraCompilers;
     QList<CMakeBuildTarget> m_buildTargets;
 
-    bool checkConfiguration();
-    bool hasConfigChanged();
-
     // Parsing state:
     BuildDirParameters m_parameters;
-    int m_reparseParameters;
+    int m_reparseParameters = REPARSE_DEFAULT;
     mutable std::unordered_map<Utils::FilePath, std::unique_ptr<Utils::TemporaryDirectory>>
         m_buildDirToTempDir;
     FileApiReader m_reader;
diff --git a/src/plugins/cmakeprojectmanager/cmakeconfigitem.cpp b/src/plugins/cmakeprojectmanager/cmakeconfigitem.cpp
index a57d780d453..f979c283f35 100644
--- a/src/plugins/cmakeprojectmanager/cmakeconfigitem.cpp
+++ b/src/plugins/cmakeprojectmanager/cmakeconfigitem.cpp
@@ -284,6 +284,54 @@ static QByteArrayList splitCMakeCacheLine(const QByteArray &line) {
                             << line.mid(equalPos + 1);
 }
 
+static CMakeConfigItem setItemFromString(const QString &input)
+{
+    return CMakeConfigItem::fromString(input);
+}
+
+static CMakeConfigItem unsetItemFromString(const QString &input)
+{
+    CMakeConfigItem item(input.toUtf8(), QByteArray());
+    item.isUnset = true;
+    return item;
+}
+
+QList<CMakeConfigItem> CMakeConfigItem::itemsFromArguments(const QStringList &list)
+{
+    CMakeConfig result;
+    bool inSet = false;
+    bool inUnset = false;
+    for (const QString &i : list) {
+        if (inSet) {
+            inSet = false;
+            result.append(setItemFromString(i));
+            continue;
+        }
+        if (inUnset) {
+            inUnset = false;
+            result.append(unsetItemFromString(i));
+            continue;
+        }
+        if (i == "-U") {
+            inUnset = true;
+            continue;
+        }
+        if (i == "-D") {
+            inSet = true;
+            continue;
+        }
+        if (i.startsWith("-U")) {
+            result.append(unsetItemFromString(i.mid(2)));
+            continue;
+        }
+        if (i.startsWith("-D")) {
+            result.append(setItemFromString(i.mid(2)));
+        }
+        // ignore everything else as that does not define a configuration option
+    }
+    return result;
+}
+
 QList<CMakeConfigItem> CMakeConfigItem::itemsFromFile(const Utils::FilePath &cacheFile, QString *errorMessage)
 {
     CMakeConfig result;
diff --git a/src/plugins/cmakeprojectmanager/cmakeconfigitem.h b/src/plugins/cmakeprojectmanager/cmakeconfigitem.h
index c99f1e64f7e..10c7651f6f7 100644
--- a/src/plugins/cmakeprojectmanager/cmakeconfigitem.h
+++ b/src/plugins/cmakeprojectmanager/cmakeconfigitem.h
@@ -64,6 +64,7 @@ public:
 
     static std::function<bool(const CMakeConfigItem &a, const CMakeConfigItem &b)> sortOperator();
     static CMakeConfigItem fromString(const QString &s);
+    static QList<CMakeConfigItem> itemsFromArguments(const QStringList &list);
     static QList<CMakeConfigItem> itemsFromFile(const Utils::FilePath &input, QString *errorMessage);
     QString toString(const Utils::MacroExpander *expander = nullptr) const;
     QString toArgument(const Utils::MacroExpander *expander = nullptr) const;
diff --git a/src/plugins/cmakeprojectmanager/cmakekitinformation.cpp b/src/plugins/cmakeprojectmanager/cmakekitinformation.cpp
index 89ab5a9aab0..86c9f8114b2 100644
--- a/src/plugins/cmakeprojectmanager/cmakekitinformation.cpp
+++ b/src/plugins/cmakeprojectmanager/cmakekitinformation.cpp
@@ -974,6 +974,12 @@ void CMakeConfigurationKitAspect::fromStringList(Kit *k, const QStringList &in)
     setConfiguration(k, result);
 }
 
+QStringList CMakeConfigurationKitAspect::toArgumentsList(const Kit *k)
+{
+    return Utils::transform(CMakeConfigurationKitAspect::configuration(k),
+                            [](const CMakeConfigItem &i) { return i.toArgument(nullptr); });
+}
+
 CMakeConfig CMakeConfigurationKitAspect::defaultConfiguration(const Kit *k)
 {
     Q_UNUSED(k)
diff --git a/src/plugins/cmakeprojectmanager/cmakekitinformation.h b/src/plugins/cmakeprojectmanager/cmakekitinformation.h
index f2579f3282c..fd6af308cff 100644
--- a/src/plugins/cmakeprojectmanager/cmakekitinformation.h
+++ b/src/plugins/cmakeprojectmanager/cmakekitinformation.h
@@ -101,6 +101,8 @@ public:
     static QStringList toStringList(const ProjectExplorer::Kit *k);
     static void fromStringList(ProjectExplorer::Kit *k, const QStringList &in);
 
+    static QStringList toArgumentsList(const ProjectExplorer::Kit *k);
+
     static CMakeConfig defaultConfiguration(const ProjectExplorer::Kit *k);
 
     // KitAspect interface
diff --git a/src/plugins/cmakeprojectmanager/cmakeprocess.cpp b/src/plugins/cmakeprojectmanager/cmakeprocess.cpp
index e500ac8c2ec..ba6b582896a 100644
--- a/src/plugins/cmakeprojectmanager/cmakeprocess.cpp
+++ b/src/plugins/cmakeprojectmanager/cmakeprocess.cpp
@@ -113,11 +113,7 @@ void CMakeProcess::run(const BuildDirParameters &parameters, const QStringList &
     connect(process.get(), QOverload<int, QProcess::ExitStatus>::of(&QProcess::finished),
             this, &CMakeProcess::handleProcessFinished);
 
-    QStringList args;
-    args += parameters.generatorArguments;
-    args += arguments;
-    args += srcDir;
-    Utils::CommandLine commandLine(cmake->cmakeExecutable(), args);
+    Utils::CommandLine commandLine(cmake->cmakeExecutable(), QStringList({"-S", srcDir, QString("-B"), workDirectory.toString()}) + arguments);
 
     TaskHub::clearTasks(ProjectExplorer::Constants::TASK_CATEGORY_BUILDSYSTEM);
 
diff --git a/src/plugins/cmakeprojectmanager/configmodel.cpp b/src/plugins/cmakeprojectmanager/configmodel.cpp
index b6134b14fa0..c0f075fda6b 100644
--- a/src/plugins/cmakeprojectmanager/configmodel.cpp
+++ b/src/plugins/cmakeprojectmanager/configmodel.cpp
@@ -96,24 +96,6 @@ void ConfigModel::setConfigurationFromKit(const QHash<QString, QString> &kitConf
     setConfiguration(m_configuration);
 }
 
-void ConfigModel::setConfigurationForCMake(const QHash<QString, QString> &config)
-{
-    for (InternalDataItem &i : m_configuration) {
-        if (!config.contains(i.key))
-            continue;
-
-        const QString v = config.value(i.key);
-        if (i.value == v) {
-            i.newValue.clear();
-            i.isUserChanged = false;
-        } else {
-            i.newValue = v;
-            i.isUserChanged = true;
-        }
-    }
-    setConfiguration(m_configuration);
-}
-
 void ConfigModel::flush()
 {
     setConfiguration(QList<InternalDataItem>());
diff --git a/src/plugins/cmakeprojectmanager/configmodel.h b/src/plugins/cmakeprojectmanager/configmodel.h
index 5844c388f96..7c5cfa205b1 100644
--- a/src/plugins/cmakeprojectmanager/configmodel.h
+++ b/src/plugins/cmakeprojectmanager/configmodel.h
@@ -72,7 +72,7 @@ public:
     void setConfiguration(const CMakeConfig &config);
     void setConfiguration(const QList<DataItem> &config);
     void setConfigurationFromKit(const QHash<QString, QString> &kitConfig);
-    void setConfigurationForCMake(const QHash<QString, QString> &config);
+
     void flush();
     void resetAllChanges();
 
diff --git a/src/plugins/cmakeprojectmanager/fileapireader.cpp b/src/plugins/cmakeprojectmanager/fileapireader.cpp
index 5b252f62978..1e25125a80a 100644
--- a/src/plugins/cmakeprojectmanager/fileapireader.cpp
+++ b/src/plugins/cmakeprojectmanager/fileapireader.cpp
@@ -99,47 +99,63 @@ void FileApiReader::resetData()
     m_knownHeaders.clear();
 }
 
-void FileApiReader::parse(bool forceCMakeRun, bool forceConfiguration)
+void FileApiReader::parse(bool forceCMakeRun,
+                          bool forceInitialConfiguration,
+                          bool forceExtraConfiguration)
 {
     qCDebug(cmakeFileApiMode) << "Parse called with arguments: ForceCMakeRun:" << forceCMakeRun
-                              << " - forceConfiguration:" << forceConfiguration;
+                              << " - forceConfiguration:" << forceInitialConfiguration
+                              << " - forceExtraConfiguration:" << forceExtraConfiguration;
     startState();
 
-    if (forceConfiguration) {
-        // Initial create:
-        qCDebug(cmakeFileApiMode) << "FileApiReader: Starting CMake with forced configuration.";
-        const FilePath path = m_parameters.workDirectory.pathAppended("qtcsettings.cmake");
-        startCMakeState(QStringList({QString("-C"), path.toUserOutput()}));
-        // Keep m_isParsing enabled!
-        return;
-    }
+    const QStringList args = (forceInitialConfiguration ? m_parameters.initialCMakeArguments
+                                                        : QStringList())
+                             + (forceExtraConfiguration ? m_parameters.extraCMakeArguments
+                                                        : QStringList());
+    qCDebug(cmakeFileApiMode) << "Parameters request these CMake arguments:" << args;
 
     const QFileInfo replyFi = FileApiParser::scanForCMakeReplyFile(m_parameters.workDirectory);
     // Only need to update when one of the following conditions is met:
-    //  * The user forces the update,
+    //  * The user forces the cmake run,
+    //  * The user provided arguments,
     //  * There is no reply file,
     //  * One of the cmakefiles is newer than the replyFile and the user asked
     //    for creator to run CMake as needed,
     //  * A query file is newer than the reply file
-    const bool mustUpdate = forceCMakeRun || !replyFi.exists()
-                            || (m_parameters.cmakeTool() && m_parameters.cmakeTool()->isAutoRun()
-                                && anyOf(m_cmakeFiles,
-                                         [&replyFi](const FilePath &f) {
-                                             return f.toFileInfo().lastModified()
-                                                    > replyFi.lastModified();
-                                         }))
-                            || anyOf(FileApiParser::cmakeQueryFilePaths(m_parameters.workDirectory), [&replyFi](const QString &qf) {
-                                   return QFileInfo(qf).lastModified() > replyFi.lastModified();
-                               });
+    const bool hasArguments = !args.isEmpty();
+    const bool replyFileMissing = !replyFi.exists();
+    const bool cmakeFilesChanged = m_parameters.cmakeTool() && m_parameters.cmakeTool()->isAutoRun()
+                                   && anyOf(m_cmakeFiles, [&replyFi](const FilePath &f) {
+                                          return f.toFileInfo().lastModified()
+                                                 > replyFi.lastModified();
+                                      });
+    const bool queryFileChanged = anyOf(FileApiParser::cmakeQueryFilePaths(
+                                            m_parameters.workDirectory),
+                                        [&replyFi](const QString &qf) {
+                                            return QFileInfo(qf).lastModified()
+                                                   > replyFi.lastModified();
+                                        });
+
+    const bool mustUpdate = forceCMakeRun || hasArguments || replyFileMissing || cmakeFilesChanged
+                            || queryFileChanged;
+    qCDebug(cmakeFileApiMode) << QString("Do I need to run CMake? %1 "
+                                         "(force: %2 | args: %3 | missing reply: %4 | "
+                                         "cmakeFilesChanged: %5 | "
+                                         "queryFileChanged: %6)")
+                                     .arg(mustUpdate)
+                                     .arg(forceCMakeRun)
+                                     .arg(hasArguments)
+                                     .arg(replyFileMissing)
+                                     .arg(cmakeFilesChanged)
+                                     .arg(queryFileChanged);
 
     if (mustUpdate) {
-        qCDebug(cmakeFileApiMode) << "FileApiReader: Starting CMake with no arguments.";
-        startCMakeState(QStringList());
-        // Keep m_isParsing enabled!
-        return;
+        qCDebug(cmakeFileApiMode) << QString("FileApiReader: Starting CMake with \"%1\".")
+                                         .arg(args.join("\", \""));
+        startCMakeState(args);
+    } else {
+        endState(replyFi);
     }
-
-    endState(replyFi);
 }
 
 void FileApiReader::stop()
diff --git a/src/plugins/cmakeprojectmanager/fileapireader.h b/src/plugins/cmakeprojectmanager/fileapireader.h
index 2319010aa46..0b578511ecb 100644
--- a/src/plugins/cmakeprojectmanager/fileapireader.h
+++ b/src/plugins/cmakeprojectmanager/fileapireader.h
@@ -58,7 +58,7 @@ public:
     void setParameters(const BuildDirParameters &p);
 
     void resetData();
-    void parse(bool forceCMakeRun, bool forceConfiguration);
+    void parse(bool forceCMakeRun, bool forceInitialConfiguration, bool forceExtraConfiguration);
     void stop();
 
     bool isParsing() const;
diff --git a/src/plugins/projectexplorer/buildsystem.h b/src/plugins/projectexplorer/buildsystem.h
index af69ca29e48..5d38e8300c2 100644
--- a/src/plugins/projectexplorer/buildsystem.h
+++ b/src/plugins/projectexplorer/buildsystem.h
@@ -42,6 +42,7 @@ class Node;
 // BuildSystem:
 // --------------------------------------------------------------------
 
+// Check buildsystem.md for more information
 class PROJECTEXPLORER_EXPORT BuildSystem : public QObject
 {
     Q_OBJECT