diff --git a/src/plugins/cmakeprojectmanager/builddirmanager.cpp b/src/plugins/cmakeprojectmanager/builddirmanager.cpp
index be570ad6812..4e3a67e3397 100644
--- a/src/plugins/cmakeprojectmanager/builddirmanager.cpp
+++ b/src/plugins/cmakeprojectmanager/builddirmanager.cpp
@@ -47,6 +47,7 @@
 #include <QDir>
 #include <QLoggingCategory>
 #include <QMessageBox>
+#include <QPointer>
 #include <QPushButton>
 #include <QSet>
 
@@ -95,6 +96,18 @@ Utils::FilePath BuildDirManager::workDirectory(const BuildDirParameters &paramet
     return Utils::FilePath::fromString(tmpDirIt->second->path());
 }
 
+void BuildDirManager::updateReparseParameters(const int parameters)
+{
+    m_reparseParameters |= parameters;
+}
+
+int BuildDirManager::takeReparseParameters()
+{
+    int result = m_reparseParameters;
+    m_reparseParameters = REPARSE_DEFAULT;
+    return result;
+}
+
 void BuildDirManager::emitDataAvailable()
 {
     if (!isParsing())
@@ -108,6 +121,14 @@ void BuildDirManager::emitErrorOccured(const QString &message) const
     m_isHandlingError = false;
 }
 
+void BuildDirManager::emitReparseRequest() const
+{
+    if (m_reparseParameters & REPARSE_URGENT)
+        emit requestReparse();
+    else
+        emit requestDelayedReparse();
+}
+
 void BuildDirManager::updateReaderType(const BuildDirParameters &p,
                                        std::function<void()> todo)
 {
@@ -208,7 +229,7 @@ void BuildDirManager::stopParsingAndClearState()
 }
 
 void BuildDirManager::setParametersAndRequestParse(const BuildDirParameters &parameters,
-                                                   int reparseOptions)
+                                                   const int reparseParameters)
 {
     if (!parameters.cmakeTool()) {
         TaskHub::addTask(Task::Error,
@@ -222,9 +243,9 @@ void BuildDirManager::setParametersAndRequestParse(const BuildDirParameters &par
 
     m_parameters = parameters;
     m_parameters.workDirectory = workDirectory(parameters);
+    updateReparseParameters(reparseParameters);
 
-    updateReaderType(m_parameters,
-                     [this, reparseOptions]() { emit requestReparse(reparseOptions); });
+    updateReaderType(m_parameters, [this]() { emitReparseRequest(); });
 }
 
 CMakeBuildConfiguration *BuildDirManager::buildConfiguration() const
@@ -248,7 +269,8 @@ void BuildDirManager::becameDirty()
     if (!tool->isAutoRun())
         return;
 
-    emit requestReparse(REPARSE_CHECK_CONFIGURATION | REPARSE_SCAN);
+    updateReparseParameters(REPARSE_CHECK_CONFIGURATION | REPARSE_SCAN);
+    emit requestReparse();
 }
 
 void BuildDirManager::resetData()
@@ -276,19 +298,30 @@ bool BuildDirManager::persistCMakeState()
     return true;
 }
 
-void BuildDirManager::parse(int reparseParameters)
+void BuildDirManager::requestFilesystemScan()
 {
-    qCDebug(cmakeBuildDirManagerLog)
-        << "Parse called with flags:" << flagsString(reparseParameters);
+    updateReparseParameters(REPARSE_SCAN);
+}
 
+bool BuildDirManager::isFilesystemScanRequested() const
+{
+    return m_reparseParameters & REPARSE_SCAN;
+}
+
+void BuildDirManager::parse()
+{
     QTC_ASSERT(m_parameters.isValid(), return );
     QTC_ASSERT(m_reader, return);
-    QTC_ASSERT((reparseParameters & REPARSE_IGNORE) == 0, return);
 
     m_reader->stop();
 
     TaskHub::clearTasks(ProjectExplorer::Constants::TASK_CATEGORY_BUILDSYSTEM);
 
+    int reparseParameters = takeReparseParameters();
+
+    qCDebug(cmakeBuildDirManagerLog)
+        << "Parse called with flags:" << flagsString(reparseParameters);
+
     const QString cache = m_parameters.workDirectory.pathAppended("CMakeCache.txt").toString();
     if (!QFileInfo::exists(cache)) {
         reparseParameters |= REPARSE_FORCE_CONFIGURATION | REPARSE_FORCE_CMAKE_RUN;
@@ -323,8 +356,10 @@ QVector<FilePath> BuildDirManager::takeProjectFilesToWatch()
 
     if (!toWatch.isEmpty()) {
         connect(project(), &Project::projectFileIsDirty, this, [this]() {
-            if (m_parameters.cmakeTool() && m_parameters.cmakeTool()->isAutoRun())
-                requestReparse(REPARSE_DEFAULT);
+            if (m_parameters.cmakeTool() && m_parameters.cmakeTool()->isAutoRun()) {
+                updateReparseParameters(REPARSE_DEFAULT);
+                emit requestReparse();
+            }
         });
     } else {
         disconnect(project(), nullptr, this, nullptr);
@@ -452,8 +487,6 @@ QString BuildDirManager::flagsString(int reparseFlags)
             result += " CHECK_CONFIG";
         if (reparseFlags & REPARSE_SCAN)
             result += " SCAN";
-        if (reparseFlags & REPARSE_IGNORE)
-            result += " IGNORE";
     }
     return result.trimmed();
 }
diff --git a/src/plugins/cmakeprojectmanager/builddirmanager.h b/src/plugins/cmakeprojectmanager/builddirmanager.h
index 99a1e7adb0b..136ebc1c686 100644
--- a/src/plugins/cmakeprojectmanager/builddirmanager.h
+++ b/src/plugins/cmakeprojectmanager/builddirmanager.h
@@ -60,6 +60,17 @@ class BuildDirManager : public QObject
     Q_OBJECT
 
 public:
+    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
+        REPARSE_SCAN = (1 << 3),                // Run filesystem scan
+        REPARSE_URGENT = (1 << 4),              // Do not delay the parser run by 1s
+    };
+
+    static QString flagsString(int reparseFlags);
+
     BuildDirManager(CMakeProject *project);
     ~BuildDirManager() final;
 
@@ -67,7 +78,8 @@ public:
 
     void stopParsingAndClearState();
 
-    void setParametersAndRequestParse(const BuildDirParameters &parameters, int reparseOptions);
+    void setParametersAndRequestParse(const BuildDirParameters &parameters,
+                                      const int reparseOptions);
     // nullptr if the BC is not active anymore!
     CMakeBuildConfiguration *buildConfiguration() const;
     CMakeProject *project() const {return m_project; }
@@ -78,7 +90,9 @@ public:
     void resetData();
     bool persistCMakeState();
 
-    void parse(int reparseParameters);
+    void requestFilesystemScan();
+    bool isFilesystemScanRequested() const;
+    void parse();
 
     QVector<Utils::FilePath> takeProjectFilesToWatch();
     std::unique_ptr<CMakeProjectNode> generateProjectTree(const QList<const ProjectExplorer::FileNode *> &allFiles,
@@ -91,32 +105,20 @@ public:
     static CMakeConfig parseCMakeConfiguration(const Utils::FilePath &cacheFile,
                                                QString *errorMessage);
 
-    enum ReparseParameters {
-        REPARSE_DEFAULT = BuildSystem::PARAM_DEFAULT, // use defaults
-        REPARSE_URGENT = BuildSystem::PARAM_URGENT,   // Do not wait for more requests, start ASAP
-        REPARSE_IGNORE = BuildSystem::PARAM_IGNORE,
-
-        REPARSE_FORCE_CMAKE_RUN = (1
-                                   << (BuildSystem::PARAM_CUSTOM_OFFSET + 0)), // Force cmake to run
-        REPARSE_FORCE_CONFIGURATION = (1 << (BuildSystem::PARAM_CUSTOM_OFFSET
-                                             + 1)), // Force configuration arguments to cmake
-        REPARSE_CHECK_CONFIGURATION
-        = (1 << (BuildSystem::PARAM_CUSTOM_OFFSET
-                 + 2)), // Check and warn if on-disk config and QtC config differ
-        REPARSE_SCAN = (1 << (BuildSystem::PARAM_CUSTOM_OFFSET + 3)), // Run filesystem scan
-    };
-
-    static QString flagsString(int reparseFlags);
-
 signals:
-    void requestReparse(int reparseParameters) const;
+    void requestReparse() const;
+    void requestDelayedReparse() const;
     void parsingStarted() const;
     void dataAvailable() const;
     void errorOccured(const QString &err) const;
 
 private:
+    void updateReparseParameters(const int parameters);
+    int takeReparseParameters();
+
     void emitDataAvailable();
     void emitErrorOccured(const QString &message) const;
+    void emitReparseRequest() const;
     bool checkConfiguration();
 
     Utils::FilePath workDirectory(const BuildDirParameters &parameters) const;
@@ -129,6 +131,7 @@ private:
     void becameDirty();
 
     BuildDirParameters m_parameters;
+    int m_reparseParameters;
     CMakeProject *m_project = nullptr;
     mutable std::unordered_map<Utils::FilePath, std::unique_ptr<Utils::TemporaryDirectory>> m_buildDirToTempDir;
     mutable std::unique_ptr<BuildDirReader> m_reader;
diff --git a/src/plugins/cmakeprojectmanager/cmakebuildconfiguration.cpp b/src/plugins/cmakeprojectmanager/cmakebuildconfiguration.cpp
index 2a96c9b1f43..26c7327a0bc 100644
--- a/src/plugins/cmakeprojectmanager/cmakebuildconfiguration.cpp
+++ b/src/plugins/cmakeprojectmanager/cmakebuildconfiguration.cpp
@@ -93,12 +93,13 @@ CMakeBuildConfiguration::CMakeBuildConfiguration(Target *parent, Core::Id id)
     BuildSystem *bs = qobject_cast<CMakeBuildSystem *>(project()->buildSystem());
 
     // BuildDirManager:
-    connect(&m_buildDirManager, &BuildDirManager::requestReparse, this, [this, bs](int options) {
-        if (isActive()) {
-            qCDebug(cmakeBuildConfigurationLog)
-                << "Passing on reparse request with flags" << BuildDirManager::flagsString(options);
-            bs->requestParse(options);
-        }
+    connect(&m_buildDirManager, &BuildDirManager::requestReparse, this, [this, bs]() {
+        if (isActive())
+            bs->requestParse();
+    });
+    connect(&m_buildDirManager, &BuildDirManager::requestDelayedReparse, this, [this, bs]() {
+        if (isActive())
+            bs->requestDelayedParse();
     });
     connect(&m_buildDirManager,
             &BuildDirManager::dataAvailable,
diff --git a/src/plugins/cmakeprojectmanager/cmakebuildsystem.cpp b/src/plugins/cmakeprojectmanager/cmakebuildsystem.cpp
index a0203742965..200f8018541 100644
--- a/src/plugins/cmakeprojectmanager/cmakebuildsystem.cpp
+++ b/src/plugins/cmakeprojectmanager/cmakebuildsystem.cpp
@@ -30,38 +30,6 @@
 #include "cmakeprojectconstants.h"
 #include "cmakeprojectnodes.h"
 
-#if 0
-#include "cmakebuildstep.h"
-#include "cmakekitinformation.h"
-#include "cmakeprojectmanager.h"
-#include "cmakeprojectnodes.h"
-
-#include <cpptools/cpprawprojectpart.h>
-#include <cpptools/cpptoolsconstants.h>
-
-#include <cpptools/projectinfo.h>
-#include <projectexplorer/buildsteplist.h>
-#include <projectexplorer/buildtargetinfo.h>
-#include <projectexplorer/deploymentdata.h>
-#include <projectexplorer/headerpath.h>
-#include <projectexplorer/kitinformation.h>
-#include <projectexplorer/kitmanager.h>
-#include <projectexplorer/projectexplorerconstants.h>
-#include <projectexplorer/toolchain.h>
-#include <qmljs/qmljsmodelmanagerinterface.h>
-#include <qtsupport/baseqtversion.h>
-#include <qtsupport/qtkitinformation.h>
-
-#include <utils/algorithm.h>
-#include <utils/hostosinfo.h>
-#include <utils/qtcprocess.h>
-#include <utils/stringutils.h>
-
-#include <QDir>
-#include <QElapsedTimer>
-#include <QSet>
-#endif
-
 #include <coreplugin/progressmanager/progressmanager.h>
 #include <cpptools/cppprojectupdater.h>
 #include <cpptools/generatedcodemodelsupport.h>
@@ -79,85 +47,12 @@
 using namespace ProjectExplorer;
 using namespace Utils;
 
-namespace {
-
-CMakeProjectManager::Internal::CMakeBuildConfiguration *activeBc(Project *p)
-{
-    if (!p)
-        return nullptr;
-
-    return qobject_cast<CMakeProjectManager::Internal::CMakeBuildConfiguration *>(
-        p->activeTarget() ? p->activeTarget()->activeBuildConfiguration() : nullptr);
-}
-
-} // namespace
-
 namespace CMakeProjectManager {
 
 using namespace Internal;
 
 Q_LOGGING_CATEGORY(cmakeBuildSystemLog, "qtc.cmake.buildsystem", QtWarningMsg);
 
-// --------------------------------------------------------------------
-// BuildSystem:
-// --------------------------------------------------------------------
-
-BuildSystem::BuildSystem(Project *project)
-    : m_project(project)
-{
-    QTC_CHECK(project);
-
-    // Timer:
-    m_delayedParsingTimer.setSingleShot(true);
-
-    connect(&m_delayedParsingTimer, &QTimer::timeout, this, &BuildSystem::triggerParsing);
-}
-
-BuildSystem::~BuildSystem() = default;
-
-Project *BuildSystem::project() const
-{
-    return m_project;
-}
-
-bool BuildSystem::isWaitingForParse() const
-{
-    return m_delayedParsingTimer.isActive();
-}
-
-void BuildSystem::requestParse(int reparseParameters)
-{
-    QTC_ASSERT(!(reparseParameters & PARAM_ERROR), return );
-    if (reparseParameters & PARAM_IGNORE)
-        return;
-
-    m_delayedParsingTimer.setInterval((reparseParameters & PARAM_URGENT) ? 0 : 1000);
-    m_delayedParsingTimer.start();
-    m_delayedParsingParameters = m_delayedParsingParameters | reparseParameters;
-}
-
-void BuildSystem::triggerParsing()
-{
-    int parameters = m_delayedParsingParameters;
-    m_delayedParsingParameters = BuildSystem::PARAM_DEFAULT;
-
-    QTC_CHECK(!m_project->isParsing());
-    QTC_ASSERT((parameters & BuildSystem::PARAM_ERROR) == 0, return );
-    if (parameters & BuildSystem::PARAM_IGNORE)
-        return;
-
-    // Clear buildsystem specific parameters before passing them on!
-    parameters = parameters
-                 & ~(BuildSystem::PARAM_ERROR | BuildSystem::PARAM_IGNORE
-                     | BuildSystem::PARAM_URGENT);
-
-    {
-        ParsingContext ctx(m_project->guardParsingRun(), parameters, m_project, activeBc(m_project));
-        if (validateParsingContext(ctx))
-            parseProject(std::move(ctx));
-    }
-}
-
 // --------------------------------------------------------------------
 // CMakeBuildSystem:
 // --------------------------------------------------------------------
@@ -227,13 +122,12 @@ void CMakeBuildSystem::parseProject(ParsingContext &&ctx)
     m_currentContext = std::move(ctx);
 
     auto bc = qobject_cast<CMakeBuildConfiguration *>(m_currentContext.buildConfiguration);
-
-    int parameters = m_currentContext.parameters;
+    QTC_ASSERT(bc, return );
 
     if (m_allFiles.isEmpty())
-        parameters |= BuildDirManager::REPARSE_SCAN;
+        bc->m_buildDirManager.requestFilesystemScan();
 
-    m_waitingForScan = parameters & BuildDirManager::REPARSE_SCAN;
+    m_waitingForScan = bc->m_buildDirManager.isFilesystemScanRequested();
     m_waitingForParse = true;
     m_combinedScanAndParseResult = true;
 
@@ -246,7 +140,7 @@ void CMakeBuildSystem::parseProject(ParsingContext &&ctx)
                                        "CMake.Scan.Tree");
     }
 
-    bc->m_buildDirManager.parse(parameters);
+    bc->m_buildDirManager.parse();
 }
 
 void CMakeBuildSystem::handleTreeScanningFinished()
diff --git a/src/plugins/cmakeprojectmanager/cmakebuildsystem.h b/src/plugins/cmakeprojectmanager/cmakebuildsystem.h
index c30a29d5a78..1170a38e120 100644
--- a/src/plugins/cmakeprojectmanager/cmakebuildsystem.h
+++ b/src/plugins/cmakeprojectmanager/cmakebuildsystem.h
@@ -25,20 +25,12 @@
 
 #pragma once
 
-#include <projectexplorer/project.h>
-#include <projectexplorer/treescanner.h>
-
-#include <QTimer>
+#include <projectexplorer/buildsystem.h>
 
 namespace CppTools {
 class CppProjectUpdater;
 } // namespace CppTools
 
-namespace ProjectExplorer {
-class BuildConfiguration;
-class ExtraCompiler;
-} // namespace ProjectExplorer
-
 namespace CMakeProjectManager {
 
 class CMakeProject;
@@ -47,88 +39,11 @@ namespace Internal {
 class CMakeBuildConfiguration;
 } // namespace Internal
 
-// --------------------------------------------------------------------
-// BuildSystem:
-// --------------------------------------------------------------------
-
-class BuildSystem : public QObject
-{
-    Q_OBJECT
-
-public:
-    const static int PARAM_CUSTOM_OFFSET = 3;
-    enum Parameters : int {
-        PARAM_DEFAULT = 0, // use defaults
-
-        PARAM_IGNORE = (1 << (PARAM_CUSTOM_OFFSET - 3)), // Ignore this request without raising a fuss
-        PARAM_ERROR = (1 << (PARAM_CUSTOM_OFFSET - 2)), // Ignore this request and warn
-
-        PARAM_URGENT = (1 << (PARAM_CUSTOM_OFFSET - 1)), // Do not wait for more requests, start ASAP
-    };
-
-    explicit BuildSystem(ProjectExplorer::Project *project);
-    ~BuildSystem() override;
-
-    BuildSystem(const BuildSystem &other) = delete;
-
-    ProjectExplorer::Project *project() const;
-
-    bool isWaitingForParse() const;
-    void requestParse(int reparseParameters); // request a (delayed!) parser run.
-
-protected:
-    class ParsingContext
-    {
-    public:
-        ParsingContext() = default;
-
-        ParsingContext(const ParsingContext &other) = delete;
-        ParsingContext &operator=(const ParsingContext &other) = delete;
-        ParsingContext(ParsingContext &&other) = default;
-        ParsingContext &operator=(ParsingContext &&other) = default;
-
-        ProjectExplorer::Project::ParseGuard guard;
-
-        int parameters = PARAM_DEFAULT;
-        ProjectExplorer::Project *project = nullptr;
-        ProjectExplorer::BuildConfiguration *buildConfiguration = nullptr;
-
-    private:
-        ParsingContext(ProjectExplorer::Project::ParseGuard &&g,
-                       int params,
-                       ProjectExplorer::Project *p,
-                       ProjectExplorer::BuildConfiguration *bc)
-            : guard(std::move(g))
-            , parameters(params)
-            , project(p)
-            , buildConfiguration(bc)
-        {}
-
-        friend class BuildSystem;
-    };
-
-    virtual bool validateParsingContext(const ParsingContext &ctx)
-    {
-        Q_UNUSED(ctx)
-        return true;
-    }
-
-    virtual void parseProject(ParsingContext &&ctx) = 0; // actual code to parse project
-
-private:
-    void triggerParsing();
-
-    ProjectExplorer::Project *m_project;
-
-    QTimer m_delayedParsingTimer;
-    int m_delayedParsingParameters = PARAM_DEFAULT;
-};
-
 // --------------------------------------------------------------------
 // CMakeBuildSystem:
 // --------------------------------------------------------------------
 
-class CMakeBuildSystem : public BuildSystem
+class CMakeBuildSystem : public ProjectExplorer::BuildSystem
 {
     Q_OBJECT
 
diff --git a/src/plugins/cmakeprojectmanager/cmakeproject.cpp b/src/plugins/cmakeprojectmanager/cmakeproject.cpp
index caa8e0eb130..13dae9c4406 100644
--- a/src/plugins/cmakeprojectmanager/cmakeproject.cpp
+++ b/src/plugins/cmakeprojectmanager/cmakeproject.cpp
@@ -85,14 +85,14 @@ static CMakeBuildConfiguration *activeBc(const CMakeProject *p)
 CMakeProject::CMakeProject(const FilePath &fileName)
     : Project(Constants::CMAKEMIMETYPE, fileName)
 {
-    m_buildsystem = std::make_unique<CMakeBuildSystem>(this);
-
     setId(CMakeProjectManager::Constants::CMAKEPROJECT_ID);
     setProjectLanguages(Core::Context(ProjectExplorer::Constants::CXX_LANGUAGE_ID));
     setDisplayName(projectDirectory().fileName());
     setCanBuildProducts();
     setKnowsAllBuildExecutables(false);
     setHasMakeInstallEquivalent(true);
+
+    setBuildSystem(std::make_unique<CMakeBuildSystem>(this));
 }
 
 CMakeProject::~CMakeProject() = default;
diff --git a/src/plugins/cmakeprojectmanager/cmakeproject.h b/src/plugins/cmakeprojectmanager/cmakeproject.h
index 75a8ed81c41..cf7a1f058ee 100644
--- a/src/plugins/cmakeprojectmanager/cmakeproject.h
+++ b/src/plugins/cmakeprojectmanager/cmakeproject.h
@@ -32,10 +32,8 @@
 #include "cmakebuildtarget.h"
 #include "cmakeprojectimporter.h"
 
-#include <projectexplorer/extracompiler.h>
+#include <projectexplorer/buildsystem.h>
 #include <projectexplorer/project.h>
-#include <projectexplorer/projectmacro.h>
-#include <projectexplorer/treescanner.h>
 
 #include <utils/fileutils.h>
 
@@ -50,8 +48,6 @@ namespace ProjectExplorer { class FileNode; }
 
 namespace CMakeProjectManager {
 
-class BuildSystem;
-
 namespace Internal {
 class CMakeBuildConfiguration;
 class CMakeBuildSettingsWidget;
@@ -66,8 +62,6 @@ public:
     explicit CMakeProject(const Utils::FilePath &filename);
     ~CMakeProject() final;
 
-    BuildSystem *buildSystem() const { return m_buildsystem.get(); }
-
     ProjectExplorer::Tasks projectIssues(const ProjectExplorer::Kit *k) const final;
 
     void runCMake();
@@ -94,11 +88,6 @@ private:
 
     mutable std::unique_ptr<Internal::CMakeProjectImporter> m_projectImporter;
 
-    std::unique_ptr<CMakeBuildSystem> m_buildsystem;
-
-    // friend class Internal::CMakeBuildConfiguration;
-    // friend class Internal::CMakeBuildSettingsWidget;
-
     friend class CMakeBuildSystem;
 };
 
diff --git a/src/plugins/cmakeprojectmanager/cmakeprojectmanager.cpp b/src/plugins/cmakeprojectmanager/cmakeprojectmanager.cpp
index 21be7d1995d..10f8202ad5d 100644
--- a/src/plugins/cmakeprojectmanager/cmakeprojectmanager.cpp
+++ b/src/plugins/cmakeprojectmanager/cmakeprojectmanager.cpp
@@ -32,12 +32,13 @@
 #include "cmaketoolmanager.h"
 #include "cmakeprojectnodes.h"
 
-#include <coreplugin/icore.h>
-#include <coreplugin/messagemanager.h>
+#include <coreplugin/actionmanager/actioncontainer.h>
 #include <coreplugin/actionmanager/actionmanager.h>
 #include <coreplugin/actionmanager/command.h>
-#include <coreplugin/actionmanager/actioncontainer.h>
 #include <coreplugin/editormanager/editormanager.h>
+#include <coreplugin/editormanager/ieditor.h>
+#include <coreplugin/icore.h>
+#include <coreplugin/messagemanager.h>
 #include <projectexplorer/buildmanager.h>
 #include <projectexplorer/projectexplorer.h>
 #include <projectexplorer/projectexplorerconstants.h>
diff --git a/src/plugins/projectexplorer/CMakeLists.txt b/src/plugins/projectexplorer/CMakeLists.txt
index 2e065ea3bf4..0476aea722f 100644
--- a/src/plugins/projectexplorer/CMakeLists.txt
+++ b/src/plugins/projectexplorer/CMakeLists.txt
@@ -21,6 +21,7 @@ add_qtc_plugin(ProjectExplorer
     buildstep.cpp buildstep.h
     buildsteplist.cpp buildsteplist.h
     buildstepspage.cpp buildstepspage.h
+    buildsystem.cpp buildsystem.h
     buildtargetinfo.h
     clangparser.cpp clangparser.h
     codestylesettingspropertiespage.cpp codestylesettingspropertiespage.h codestylesettingspropertiespage.ui
diff --git a/src/plugins/projectexplorer/buildsystem.cpp b/src/plugins/projectexplorer/buildsystem.cpp
new file mode 100644
index 00000000000..84c9b123811
--- /dev/null
+++ b/src/plugins/projectexplorer/buildsystem.cpp
@@ -0,0 +1,102 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#include "buildsystem.h"
+
+#include "buildconfiguration.h"
+#include "target.h"
+
+#include <utils/qtcassert.h>
+
+using namespace Utils;
+
+namespace ProjectExplorer {
+
+// --------------------------------------------------------------------
+// BuildSystem:
+// --------------------------------------------------------------------
+
+BuildSystem::BuildSystem(Project *project)
+    : m_project(project)
+{
+    QTC_CHECK(project);
+
+    // Timer:
+    m_delayedParsingTimer.setSingleShot(true);
+
+    connect(&m_delayedParsingTimer, &QTimer::timeout, this, &BuildSystem::triggerParsing);
+}
+
+Project *BuildSystem::project() const
+{
+    return m_project;
+}
+
+bool BuildSystem::isWaitingForParse() const
+{
+    return m_delayedParsingTimer.isActive();
+}
+
+void BuildSystem::requestParse()
+{
+    requestParse(0);
+}
+
+void BuildSystem::requestDelayedParse()
+{
+    requestParse(1000);
+}
+
+void BuildSystem::requestParse(int delay)
+{
+    m_delayedParsingTimer.setInterval(delay);
+    m_delayedParsingTimer.start();
+}
+
+void BuildSystem::triggerParsing()
+{
+    QTC_CHECK(!project()->isParsing());
+
+    Project *p = project();
+    Target *t = p->activeTarget();
+    BuildConfiguration *bc = t ? t->activeBuildConfiguration() : nullptr;
+
+    MacroExpander *e = nullptr;
+    if (bc)
+        e = bc->macroExpander();
+    else if (t)
+        e = t->macroExpander();
+    else
+        e = p->macroExpander();
+
+    Utils::Environment env = p->activeParseEnvironment();
+
+    ParsingContext ctx(p->guardParsingRun(), p, bc, e, env);
+
+    if (validateParsingContext(ctx))
+        parseProject(std::move(ctx));
+}
+
+} // namespace ProjectExplorer
diff --git a/src/plugins/projectexplorer/buildsystem.h b/src/plugins/projectexplorer/buildsystem.h
new file mode 100644
index 00000000000..dd8456074c8
--- /dev/null
+++ b/src/plugins/projectexplorer/buildsystem.h
@@ -0,0 +1,111 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include "projectexplorer_export.h"
+
+#include "project.h"
+#include "treescanner.h"
+
+#include <QTimer>
+
+namespace ProjectExplorer {
+
+class BuildConfiguration;
+class ExtraCompiler;
+
+// --------------------------------------------------------------------
+// BuildSystem:
+// --------------------------------------------------------------------
+
+class PROJECTEXPLORER_EXPORT BuildSystem : public QObject
+{
+    Q_OBJECT
+
+public:
+    explicit BuildSystem(Project *project);
+
+    BuildSystem(const BuildSystem &other) = delete;
+
+    Project *project() const;
+
+    bool isWaitingForParse() const;
+
+    void requestParse();
+    void requestDelayedParse();
+
+protected:
+    class ParsingContext
+    {
+    public:
+        ParsingContext() = default;
+
+        ParsingContext(const ParsingContext &other) = delete;
+        ParsingContext &operator=(const ParsingContext &other) = delete;
+        ParsingContext(ParsingContext &&other) = default;
+        ParsingContext &operator=(ParsingContext &&other) = default;
+
+        Project::ParseGuard guard;
+
+        Project *project = nullptr;
+        BuildConfiguration *buildConfiguration = nullptr;
+        Utils::MacroExpander *expander = nullptr;
+        Utils::Environment environment;
+
+    private:
+        ParsingContext(Project::ParseGuard &&g,
+                       Project *p,
+                       BuildConfiguration *bc,
+                       Utils::MacroExpander *e,
+                       Utils::Environment &env)
+            : guard(std::move(g))
+            , project(p)
+            , buildConfiguration(bc)
+            , expander(e)
+            , environment(env)
+        {}
+
+        friend class BuildSystem;
+    };
+
+    virtual bool validateParsingContext(const ParsingContext &ctx)
+    {
+        Q_UNUSED(ctx)
+        return true;
+    }
+
+    virtual void parseProject(ParsingContext &&ctx) = 0; // actual code to parse project
+
+private:
+    void requestParse(int delay); // request a (delayed!) parser run.
+    void triggerParsing();
+
+    QTimer m_delayedParsingTimer;
+
+    Project *m_project;
+};
+
+} // namespace ProjectExplorer
diff --git a/src/plugins/projectexplorer/project.cpp b/src/plugins/projectexplorer/project.cpp
index d881c80ce06..1d7cd11d9cc 100644
--- a/src/plugins/projectexplorer/project.cpp
+++ b/src/plugins/projectexplorer/project.cpp
@@ -27,6 +27,7 @@
 
 #include "buildconfiguration.h"
 #include "buildinfo.h"
+#include "buildsystem.h"
 #include "deployconfiguration.h"
 #include "editorconfiguration.h"
 #include "kit.h"
@@ -182,6 +183,7 @@ public:
     bool m_knowsAllBuildExecutables = true;
     bool m_hasMakeInstallEquivalent = false;
     bool m_needsBuildConfigurations = true;
+    std::unique_ptr<BuildSystem> m_buildSystem;
     std::unique_ptr<Core::IDocument> m_document;
     std::vector<std::unique_ptr<Core::IDocument>> m_extraProjectDocuments;
     std::unique_ptr<ProjectNode> m_rootProjectNode;
@@ -253,6 +255,11 @@ bool Project::canBuildProducts() const
     return d->m_canBuildProducts;
 }
 
+BuildSystem *Project::buildSystem() const
+{
+    return d->m_buildSystem.get();
+}
+
 Utils::FilePath Project::projectFilePath() const
 {
     QTC_ASSERT(d->m_document, return Utils::FilePath());
@@ -879,6 +886,12 @@ Utils::Environment Project::activeParseEnvironment() const
     return result;
 }
 
+void Project::setBuildSystem(std::unique_ptr<BuildSystem> &&bs)
+{
+    QTC_ASSERT(!bs->parent(), bs->setParent(nullptr));
+    d->m_buildSystem = std::move(bs);
+}
+
 Core::Context Project::projectContext() const
 {
     return Core::Context(d->m_id);
diff --git a/src/plugins/projectexplorer/project.h b/src/plugins/projectexplorer/project.h
index 082010d6c3e..c4f29f0d1a8 100644
--- a/src/plugins/projectexplorer/project.h
+++ b/src/plugins/projectexplorer/project.h
@@ -50,6 +50,7 @@ class MacroExpander;
 namespace ProjectExplorer {
 
 class BuildInfo;
+class BuildSystem;
 class ContainerNode;
 class EditorConfiguration;
 class FolderNode;
@@ -85,6 +86,8 @@ public:
     QString mimeType() const;
     bool canBuildProducts() const;
 
+    BuildSystem *buildSystem() const;
+
     Utils::FilePath projectFilePath() const;
     Utils::FilePath projectDirectory() const;
     static Utils::FilePath projectDirectory(const Utils::FilePath &top);
@@ -234,6 +237,8 @@ public:
     // as the main project file.
     void setExtraProjectFiles(const QVector<Utils::FilePath> &projectDocumentPaths);
 
+    Utils::Environment activeParseEnvironment() const;
+
 signals:
     void projectFileIsDirty(const Utils::FilePath &path);
 
@@ -294,7 +299,7 @@ protected:
     static ProjectExplorer::Task createProjectTask(ProjectExplorer::Task::TaskType type,
                                                    const QString &description);
 
-    Utils::Environment activeParseEnvironment() const;
+    void setBuildSystem(std::unique_ptr<BuildSystem> &&bs); // takes ownership!
 
 private:
     // Helper methods to manage parsing state and signalling
diff --git a/src/plugins/projectexplorer/projectexplorer.pro b/src/plugins/projectexplorer/projectexplorer.pro
index 90e9ed264c9..f8d9045712f 100644
--- a/src/plugins/projectexplorer/projectexplorer.pro
+++ b/src/plugins/projectexplorer/projectexplorer.pro
@@ -13,6 +13,7 @@ HEADERS += projectexplorer.h \
     addrunconfigdialog.h \
     ansifilterparser.h \
     buildinfo.h \
+    buildsystem.h \
     clangparser.h \
     configtaskhandler.h \
     desktoprunconfiguration.h \
@@ -170,6 +171,7 @@ SOURCES += projectexplorer.cpp \
     addrunconfigdialog.cpp \
     ansifilterparser.cpp \
     buildinfo.cpp \
+    buildsystem.cpp \
     clangparser.cpp \
     configtaskhandler.cpp \
     desktoprunconfiguration.cpp \
diff --git a/src/plugins/projectexplorer/projectexplorer.qbs b/src/plugins/projectexplorer/projectexplorer.qbs
index 926e6fc0815..1708495ca25 100644
--- a/src/plugins/projectexplorer/projectexplorer.qbs
+++ b/src/plugins/projectexplorer/projectexplorer.qbs
@@ -40,6 +40,7 @@ Project {
                 "buildstep.cpp", "buildstep.h",
                 "buildsteplist.cpp", "buildsteplist.h",
                 "buildstepspage.cpp", "buildstepspage.h",
+                "buildsystem.cpp", "buildsystem.h",
                 "buildtargetinfo.h",
                 "clangparser.cpp", "clangparser.h",
                 "codestylesettingspropertiespage.cpp", "codestylesettingspropertiespage.h", "codestylesettingspropertiespage.ui",