Clang: Fix system pre include search path

We now get the resource path from creator. The -fPIC case is working now
too.

Change-Id: Id191e89e6d46706748d50440038a06a349972cc9
Reviewed-by: Ivan Donchevskii <[email protected]>

42 files changed, 397 insertions, 233 deletions

diff --git a/share/qtcreator/indexer_preincludes/QtCore/qconfig.h b/share/qtcreator/indexer_preincludes/QtCore/qconfig.h
new file mode 100644
index 00000000000..9534d0d8bf4
--- /dev/null
+++ b/share/qtcreator/indexer_preincludes/QtCore/qconfig.h
@@ -0,0 +1,2 @@
+#include_next <QtCore/qconfig.h>
+#undef QT_REDUCE_RELOCATIONS
diff --git a/share/qtcreator/indexer_preincludes/QtCore/qglobal.h b/share/qtcreator/indexer_preincludes/QtCore/qglobal.h
new file mode 120000
index 00000000000..1ff1b445120
--- /dev/null
+++ b/share/qtcreator/indexer_preincludes/QtCore/qglobal.h
@@ -0,0 +1 @@
+../qglobal.h
\ No newline at end of file
diff --git a/share/qtcreator/static.pro b/share/qtcreator/static.pro
index cda672829a9..7f39ae2faed 100644
--- a/share/qtcreator/static.pro
+++ b/share/qtcreator/static.pro
@@ -22,7 +22,8 @@ DATA_DIRS = \
     qml-type-descriptions \
     modeleditor \
     glsl \
-    cplusplus
+    cplusplus \
+    indexer_preincludes
 macx: DATA_DIRS += scripts
 
 for(data_dir, DATA_DIRS) {
diff --git a/src/libs/clangsupport/clangsupport-lib.pri b/src/libs/clangsupport/clangsupport-lib.pri
index 0eaa7b8938d..201c5bf5380 100644
--- a/src/libs/clangsupport/clangsupport-lib.pri
+++ b/src/libs/clangsupport/clangsupport-lib.pri
@@ -217,6 +217,7 @@ HEADERS += \
     $$PWD/projectpartcontainer.h \
     $$PWD/sourceentry.h \
     $$PWD/modifiedtimecheckerinterface.h \
+    $$PWD/environment.h \
     $$PWD/modifiedtimechecker.h
 
 contains(QT_CONFIG, reduce_exports):CONFIG += hide_symbols
diff --git a/src/libs/clangsupport/commandlinebuilder.h b/src/libs/clangsupport/commandlinebuilder.h
index db11d773d45..dedcf1c518a 100644
--- a/src/libs/clangsupport/commandlinebuilder.h
+++ b/src/libs/clangsupport/commandlinebuilder.h
@@ -49,7 +49,8 @@ public:
                        InputFileType sourceType = InputFileType::Header,
                        FilePathView sourcePath = {},
                        FilePathView outputPath = {},
-                       FilePathView includePchPath = {})
+                       FilePathView includePchPath = {},
+                       NativeFilePathView preIncludeSearchPath = {})
     {
         commandLine.reserve(1024);
 
@@ -61,7 +62,7 @@ public:
         addLanguageVersion(projectInfo);
         addNoStdIncAndNoStdLibInc(projectInfo.language);
         addCompilerMacros(projectInfo.compilerMacros);
-        addPreIncludeSearchPath();
+        addPreIncludeSearchPath(preIncludeSearchPath);
         addProjectIncludeSearchPaths(
             sortedIncludeSearchPaths(projectInfo.projectIncludeSearchPaths));
         addSystemAndBuiltInIncludeSearchPaths(
@@ -220,18 +221,12 @@ public:
             commandLine.emplace_back(Utils::SmallString{"-D", macro.key, "=", macro.value});
     }
 
-    QString resourcePath() const
+    void addPreIncludeSearchPath(NativeFilePathView preIncludeSearchPath)
     {
-        return QDir::cleanPath(QCoreApplication::applicationDirPath() + '/' + RELATIVE_DATA_PATH
-                               + "/indexing_preincludes");
-    }
-
-    void addPreIncludeSearchPath()
-    {
-        static NativeFilePath preIncludeSearchPath{FilePath{resourcePath()}};
-
-        commandLine.emplace_back("-I");
-        commandLine.emplace_back(preIncludeSearchPath);
+        if (!preIncludeSearchPath.empty()) {
+            commandLine.emplace_back("-isystem");
+            commandLine.emplace_back(preIncludeSearchPath);
+        }
     }
 
     IncludeSearchPaths sortedIncludeSearchPaths(const IncludeSearchPaths &unsortedPaths)
diff --git a/src/tools/clangpchmanagerbackend/source/environment.h b/src/libs/clangsupport/environment.h
index 7f575fe169b..ffa4d907cc2 100644
--- a/src/tools/clangpchmanagerbackend/source/environment.h
+++ b/src/libs/clangsupport/environment.h
@@ -25,7 +25,7 @@
 
 #pragma once
 
-#include <QString>
+#include <nativefilepath.h>
 
 namespace ClangBackEnd {
 
@@ -36,8 +36,9 @@ public:
     Environment(const Environment &) = delete;
     Environment &operator=(const Environment &) = delete;
 
-    virtual QString pchBuildDirectory() const = 0;
+    virtual Utils::PathString pchBuildDirectory() const = 0;
     virtual uint hardwareConcurrency() const = 0;
+    virtual NativeFilePathView preIncludeSearchPath() const = 0;
 
 protected:
     ~Environment() = default;
diff --git a/src/plugins/clangpchmanager/pchmanagerconnectionclient.cpp b/src/plugins/clangpchmanager/pchmanagerconnectionclient.cpp
index a8e7e7a2ef4..536d80bfb3e 100644
--- a/src/plugins/clangpchmanager/pchmanagerconnectionclient.cpp
+++ b/src/plugins/clangpchmanager/pchmanagerconnectionclient.cpp
@@ -56,7 +56,8 @@ ClangPchManager::PchManagerConnectionClient::PchManagerConnectionClient(
     pchsDirectory.cd("pchs");
     m_processCreator.setArguments({connectionName(),
                                    Core::ICore::cacheResourcePath() + "/symbol-experimental-v1.db",
-                                   pchsDirectory.absolutePath()});
+                                   pchsDirectory.absolutePath(),
+                                   Core::ICore::resourcePath()});
 
     stdErrPrefixer().setPrefix("PchManagerConnectionClient.stderr: ");
     stdOutPrefixer().setPrefix("PchManagerConnectionClient.stdout: ");
diff --git a/src/plugins/clangpchmanager/projectupdater.cpp b/src/plugins/clangpchmanager/projectupdater.cpp
index f2bd14b383e..df611ef1bc7 100644
--- a/src/plugins/clangpchmanager/projectupdater.cpp
+++ b/src/plugins/clangpchmanager/projectupdater.cpp
@@ -153,7 +153,6 @@ QStringList ProjectUpdater::toolChainArguments(CppTools::ProjectPart *projectPar
     CompilerOptionsBuilder builder(*projectPart, CppTools::UseSystemHeader::Yes);
 
     builder.addWordWidth();
-    builder.addPicIfCompilerFlagsContainsIt();
     // builder.addTargetTriple(); TODO resarch why target triples are different
     builder.addExtraCodeModelFlags();
     builder.undefineClangVersionMacrosForMsvc();
diff --git a/src/plugins/clangrefactoring/refactoringconnectionclient.cpp b/src/plugins/clangrefactoring/refactoringconnectionclient.cpp
index a42ed38a161..e94e8a311ff 100644
--- a/src/plugins/clangrefactoring/refactoringconnectionclient.cpp
+++ b/src/plugins/clangrefactoring/refactoringconnectionclient.cpp
@@ -48,8 +48,9 @@ RefactoringConnectionClient::RefactoringConnectionClient(RefactoringClientInterf
     , m_serverProxy(client)
 {
     m_processCreator.setTemporaryDirectoryPattern("clangrefactoringbackend-XXXXXX");
-    m_processCreator.setArguments(
-        {connectionName(), Core::ICore::cacheResourcePath() + "/symbol-experimental-v1.db"});
+    m_processCreator.setArguments({connectionName(),
+                                   Core::ICore::cacheResourcePath() + "/symbol-experimental-v1.db",
+                                   Core::ICore::resourcePath()});
 
     stdErrPrefixer().setPrefix("RefactoringConnectionClient.stderr: ");
     stdOutPrefixer().setPrefix("RefactoringConnectionClient.stdout: ");
diff --git a/src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp b/src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp
index f8b71f61b9a..0ce49e829dd 100644
--- a/src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp
+++ b/src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp
@@ -95,23 +95,22 @@ public:
 class ApplicationEnvironment final : public ClangBackEnd::Environment
 {
 public:
-    ApplicationEnvironment(const QString &pchsPath)
-        : m_pchBuildDirectoryPath(pchsPath)
+    ApplicationEnvironment(const QString &pchsPath, const QString &preIncludeSearchPath)
+        : m_pchBuildDirectoryPath(pchsPath.toStdString())
+        , m_preIncludeSearchPath(ClangBackEnd::FilePath{preIncludeSearchPath})
     {
     }
 
-    QString pchBuildDirectory() const override
+    Utils::PathString pchBuildDirectory() const override { return m_pchBuildDirectoryPath; }
+    uint hardwareConcurrency() const override { return std::thread::hardware_concurrency(); }
+    ClangBackEnd::NativeFilePathView preIncludeSearchPath() const override
     {
-        return m_pchBuildDirectoryPath;
-    }
-
-    uint hardwareConcurrency() const override
-    {
-        return std::thread::hardware_concurrency();
+        return m_preIncludeSearchPath;
     }
 
 private:
-    QString m_pchBuildDirectoryPath;
+    Utils::PathString m_pchBuildDirectoryPath;
+    ClangBackEnd::NativeFilePath m_preIncludeSearchPath;
 };
 
 QStringList processArguments(QCoreApplication &application)
@@ -123,6 +122,7 @@ QStringList processArguments(QCoreApplication &application)
     parser.addPositionalArgument(QStringLiteral("connection"), QStringLiteral("Connection"));
     parser.addPositionalArgument(QStringLiteral("databasepath"), QStringLiteral("Database path"));
     parser.addPositionalArgument(QStringLiteral("pchspath"), QStringLiteral("PCHs path"));
+    parser.addPositionalArgument(QStringLiteral("resourcepath"), QStringLiteral("Resource path"));
 
     parser.process(application);
 
@@ -172,9 +172,9 @@ struct Data // because we have a cycle dependency
 {
     using TaskScheduler = ClangBackEnd::TaskScheduler<PchCreatorManager, ClangBackEnd::PchTaskQueue::Task>;
 
-    Data(const QString &databasePath, const QString &pchsPath)
+    Data(const QString &databasePath, const QString &pchsPath, const QString &preIncludeSearchPath)
         : database{Utils::PathString{databasePath}, 100000ms}
-        , environment{pchsPath}
+        , environment{pchsPath, preIncludeSearchPath}
     {}
     Sqlite::Database database;
     ClangBackEnd::RefactoringDatabaseInitializer<Sqlite::Database> databaseInitializer{database};
@@ -205,7 +205,8 @@ struct Data // because we have a cycle dependency
                                             projectTaskScheduler,
                                             pchCreationProgressCounter,
                                             preCompiledHeaderStorage,
-                                            database};
+                                            database,
+                                            environment};
     ClangBackEnd::PchTasksMerger pchTaskMerger{pchTaskQueue};
     ClangBackEnd::BuildDependenciesStorage<> buildDependencyStorage{database};
     ClangBackEnd::BuildDependencyCollector buildDependencyCollector{filePathCache,
@@ -266,8 +267,9 @@ int main(int argc, char *argv[])
         const QString connectionName = arguments[0];
         const QString databasePath = arguments[1];
         const QString pchsPath = arguments[2];
+        const QString preIncludeSearchPath = arguments[3] + "/indexer_preincludes";
 
-        Data data{databasePath, pchsPath};
+        Data data{databasePath, pchsPath, preIncludeSearchPath};
 
         data.includeWatcher.setNotifier(&data.clangPchManagerServer);
 
diff --git a/src/tools/clangpchmanagerbackend/source/builddependencycollector.cpp b/src/tools/clangpchmanagerbackend/source/builddependencycollector.cpp
index 1d08442c517..2bd0b87af0d 100644
--- a/src/tools/clangpchmanagerbackend/source/builddependencycollector.cpp
+++ b/src/tools/clangpchmanagerbackend/source/builddependencycollector.cpp
@@ -33,7 +33,7 @@
 #include <utils/smallstring.h>
 
 #include <algorithm>
-#include <iostream>
+
 namespace ClangBackEnd {
 
 namespace {
@@ -68,18 +68,26 @@ FilePaths generatedFilePaths(const V2::FileContainers &containers) {
 
 BuildDependency BuildDependencyCollector::create(const ProjectPartContainer &projectPart)
 {
-    CommandLineBuilder<ProjectPartContainer, Utils::SmallStringVector>
-        builder{projectPart, projectPart.toolChainArguments, InputFileType::Source};
+    if (projectPart.sourcePathIds.size()) {
+        CommandLineBuilder<ProjectPartContainer, Utils::SmallStringVector> builder{
+            projectPart,
+            projectPart.toolChainArguments,
+            InputFileType::Source,
+            {},
+            {},
+            {},
+            m_environment.preIncludeSearchPath()};
 
-    addFiles(projectPart.sourcePathIds, std::move(builder.commandLine));
+        addFiles(projectPart.sourcePathIds, std::move(builder.commandLine));
 
-    setExcludedFilePaths(m_filePathCache.filePaths(projectPart.headerPathIds +
-                                                   projectPart.sourcePathIds) +
-                         generatedFilePaths(m_generatedFiles.fileContainers()));
+        setExcludedFilePaths(
+            m_filePathCache.filePaths(projectPart.headerPathIds + projectPart.sourcePathIds)
+            + generatedFilePaths(m_generatedFiles.fileContainers()));
 
-    addUnsavedFiles(m_generatedFiles.fileContainers());
+        addUnsavedFiles(m_generatedFiles.fileContainers());
 
-    collect();
+        collect();
+    }
 
     auto buildDependency = std::move(m_buildDependency);
 
@@ -147,7 +155,7 @@ void BuildDependencyCollector::setExcludedFilePaths(ClangBackEnd::FilePaths &&ex
 void BuildDependencyCollector::addFiles(const FilePathIds &filePathIds,
                                         Utils::SmallStringVector &&arguments)
 {
-    m_clangTool.addFile(FilePath{m_environment.pchBuildDirectory().toStdString(), "dummy.cpp"},
+    m_clangTool.addFile(FilePath{m_environment.pchBuildDirectory(), "dummy.cpp"},
                         generateFakeFileContent(filePathIds),
                         std::move(arguments));
     m_buildDependency.sourceFiles.insert(m_buildDependency.sourceFiles.end(),
diff --git a/src/tools/clangpchmanagerbackend/source/clangpchmanagerbackend-source.pri b/src/tools/clangpchmanagerbackend/source/clangpchmanagerbackend-source.pri
index bbf3bf16f44..6b79e2e71fb 100644
--- a/src/tools/clangpchmanagerbackend/source/clangpchmanagerbackend-source.pri
+++ b/src/tools/clangpchmanagerbackend/source/clangpchmanagerbackend-source.pri
@@ -12,7 +12,6 @@ HEADERS += \
     $$PWD/pchmanagerserver.h \
     $$PWD/clangpchmanagerbackend_global.h \
     $$PWD/pchnotcreatederror.h \
-    $$PWD/environment.h \
     $$PWD/pchcreatorinterface.h \
     $$PWD/projectpartsmanager.h \
     $$PWD/projectpartsmanagerinterface.h \
diff --git a/src/tools/clangpchmanagerbackend/source/pchcreator.cpp b/src/tools/clangpchmanagerbackend/source/pchcreator.cpp
index 9b8683bcac5..9dd1bf36476 100644
--- a/src/tools/clangpchmanagerbackend/source/pchcreator.cpp
+++ b/src/tools/clangpchmanagerbackend/source/pchcreator.cpp
@@ -104,7 +104,8 @@ Utils::SmallStringVector PchCreator::generateClangCompilerArguments(const PchTas
                                         InputFileType::Header,
                                         {},
                                         pchOutputPath,
-                                        pchTask.systemPchPath};
+                                        pchTask.systemPchPath,
+                                        pchTask.preIncludeSearchPath};
 
     return builder.commandLine;
 }
@@ -117,7 +118,7 @@ void PchCreator::generatePch(PchTask &&pchTask)
     auto content = generatePchIncludeFileContent(pchTask.includes);
     auto pchOutputPath = generatePchFilePath();
 
-    FilePath headerFilePath{m_environment.pchBuildDirectory().toStdString(), "dummy.h"};
+    FilePath headerFilePath{m_environment.pchBuildDirectory(), "dummy.h"};
     Utils::SmallStringVector commandLine = generateClangCompilerArguments(pchTask, pchOutputPath);
 
     m_clangTool.addFile(std::move(headerFilePath), content.clone(), std::move(commandLine));
diff --git a/src/tools/clangpchmanagerbackend/source/pchtask.h b/src/tools/clangpchmanagerbackend/source/pchtask.h
index 7d8879fcbd4..74b410831e4 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtask.h
+++ b/src/tools/clangpchmanagerbackend/source/pchtask.h
@@ -94,8 +94,8 @@ public:
                && first.systemIncludeSearchPaths == second.systemIncludeSearchPaths
                && first.projectIncludeSearchPaths == second.projectIncludeSearchPaths
                && first.toolChainArguments == second.toolChainArguments
-               && first.language == second.language
-               && first.languageVersion == second.languageVersion
+               && first.preIncludeSearchPath == second.preIncludeSearchPath
+               && first.language == second.language && first.languageVersion == second.languageVersion
                && first.languageExtension == second.languageExtension;
     }
 
@@ -110,6 +110,7 @@ public:
     IncludeSearchPaths systemIncludeSearchPaths;
     IncludeSearchPaths projectIncludeSearchPaths;
     Utils::SmallStringVector toolChainArguments;
+    NativeFilePathView preIncludeSearchPath;
     Utils::Language language = Utils::Language::Cxx;
     Utils::LanguageVersion languageVersion = Utils::LanguageVersion::CXX98;
     Utils::LanguageExtension languageExtension = Utils::LanguageExtension::None;
diff --git a/src/tools/clangpchmanagerbackend/source/pchtaskqueue.cpp b/src/tools/clangpchmanagerbackend/source/pchtaskqueue.cpp
index d2507ee8641..1edbe15806b 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtaskqueue.cpp
+++ b/src/tools/clangpchmanagerbackend/source/pchtaskqueue.cpp
@@ -25,6 +25,7 @@
 
 #include "pchtaskqueue.h"
 
+#include <environment.h>
 #include <pchcreatorinterface.h>
 #include <precompiledheaderstorageinterface.h>
 #include <progresscounter.h>
@@ -147,6 +148,7 @@ std::vector<PchTaskQueue::Task> PchTaskQueue::createProjectTasks(PchTasks &&pchT
             if (pchTask.includes.size()) {
                 pchTask.systemPchPath = m_precompiledHeaderStorage.fetchSystemPrecompiledHeaderPath(
                     projectPartId);
+                pchTask.preIncludeSearchPath = m_environment.preIncludeSearchPath();
                 pchCreator.generatePch(std::move(pchTask));
                 const auto &projectPartPch = pchCreator.projectPartPch();
                 if (projectPartPch.pchPath.empty()) {
@@ -178,6 +180,7 @@ std::vector<PchTaskQueue::Task> PchTaskQueue::createSystemTasks(PchTasks &&pchTa
         return [pchTask = std::move(pchTask), this](PchCreatorInterface &pchCreator) mutable {
             const auto projectPartIds = pchTask.projectPartIds;
             if (pchTask.includes.size()) {
+                pchTask.preIncludeSearchPath = m_environment.preIncludeSearchPath();
                 pchCreator.generatePch(std::move(pchTask));
                 const auto &projectPartPch = pchCreator.projectPartPch();
                 if (projectPartPch.pchPath.empty()) {
diff --git a/src/tools/clangpchmanagerbackend/source/pchtaskqueue.h b/src/tools/clangpchmanagerbackend/source/pchtaskqueue.h
index 2d6d76ee587..80d96b8e852 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtaskqueue.h
+++ b/src/tools/clangpchmanagerbackend/source/pchtaskqueue.h
@@ -36,6 +36,7 @@ namespace ClangBackEnd {
 class PchCreatorInterface;
 class PrecompiledHeaderStorageInterface;
 class ProgressCounter;
+class Environment;
 
 class PchTaskQueue final : public PchTaskQueueInterface
 {
@@ -46,12 +47,14 @@ public:
                  TaskSchedulerInterface<Task> &projectPchTaskScheduler,
                  ProgressCounter &progressCounter,
                  PrecompiledHeaderStorageInterface &precompiledHeaderStorage,
-                 Sqlite::TransactionInterface &transactionsInterface)
+                 Sqlite::TransactionInterface &transactionsInterface,
+                 const Environment &environment)
         : m_systemPchTaskScheduler(systemPchTaskScheduler)
         , m_projectPchTaskScheduler(projectPchTaskScheduler)
         , m_precompiledHeaderStorage(precompiledHeaderStorage)
         , m_transactionsInterface(transactionsInterface)
         , m_progressCounter(progressCounter)
+        , m_environment(environment)
     {}
 
     void addSystemPchTasks(PchTasks &&pchTasks) override;
@@ -80,6 +83,7 @@ private:
     PrecompiledHeaderStorageInterface &m_precompiledHeaderStorage;
     Sqlite::TransactionInterface &m_transactionsInterface;
     ProgressCounter &m_progressCounter;
+    const Environment &m_environment;
 };
 
 } // namespace ClangBackEnd
diff --git a/src/tools/clangrefactoringbackend/clangrefactoringbackendmain.cpp b/src/tools/clangrefactoringbackend/clangrefactoringbackendmain.cpp
index 9579f760c9c..aaef21b6085 100644
--- a/src/tools/clangrefactoringbackend/clangrefactoringbackendmain.cpp
+++ b/src/tools/clangrefactoringbackend/clangrefactoringbackendmain.cpp
@@ -30,11 +30,12 @@
 #include <QDir>
 
 #include <connectionserver.h>
+#include <environment.h>
 #include <executeinloop.h>
 #include <filepathcaching.h>
 #include <generatedfiles.h>
-#include <refactoringserver.h>
 #include <refactoringclientproxy.h>
+#include <refactoringserver.h>
 #include <symbolindexing.h>
 
 #include <sqliteexception.h>
@@ -59,6 +60,8 @@ QStringList processArguments(QCoreApplication &application)
     parser.addHelpOption();
     parser.addVersionOption();
     parser.addPositionalArgument(QStringLiteral("connection"), QStringLiteral("Connection"));
+    parser.addPositionalArgument(QStringLiteral("databasepath"), QStringLiteral("Database path"));
+    parser.addPositionalArgument(QStringLiteral("resourcepath"), QStringLiteral("Resource path"));
 
     parser.process(application);
 
@@ -85,12 +88,32 @@ public:
     }
 };
 
+class ApplicationEnvironment final : public ClangBackEnd::Environment
+{
+public:
+    ApplicationEnvironment(const QString &preIncludeSearchPath)
+        : m_preIncludeSearchPath(ClangBackEnd::FilePath{preIncludeSearchPath})
+    {}
+
+    Utils::PathString pchBuildDirectory() const override { return {}; }
+    uint hardwareConcurrency() const override { return std::thread::hardware_concurrency(); }
+    ClangBackEnd::NativeFilePathView preIncludeSearchPath() const override
+    {
+        return m_preIncludeSearchPath;
+    }
+
+private:
+    ClangBackEnd::NativeFilePath m_preIncludeSearchPath;
+};
+
 struct Data // because we have a cycle dependency
 {
-    Data(const QString &databasePath)
-        : database{Utils::PathString{databasePath}, 100000ms}
+    Data(const QString &databasePath, const QString &preIncludeSearchPath)
+        : environment{preIncludeSearchPath}
+        , database{Utils::PathString{databasePath}, 100000ms}
     {}
 
+    ApplicationEnvironment environment;
     Sqlite::Database database;
     RefactoringDatabaseInitializer<Sqlite::Database> databaseInitializer{database};
     FilePathCaching filePathCache{database};
@@ -103,7 +126,8 @@ struct Data // because we have a cycle dependency
                                       executeInLoop([&] {
                                           clangCodeModelServer.setProgress(progress, total);
                                       });
-                                  }};
+                                  },
+                                  environment};
 };
 
 #ifdef Q_OS_WIN
@@ -131,8 +155,9 @@ int main(int argc, char *argv[])
         const QStringList arguments = processArguments(application);
         const QString connectionName = arguments[0];
         const QString databasePath = arguments[1];
+        const QString preIncludeSearchPath = arguments[2] + "/indexer_preincludes";
 
-        Data data{databasePath};
+        Data data{databasePath, preIncludeSearchPath};
 
         ConnectionServer<RefactoringServer, RefactoringClientProxy> connectionServer;
         connectionServer.setServer(&data.clangCodeModelServer);
diff --git a/src/tools/clangrefactoringbackend/source/symbolindexer.cpp b/src/tools/clangrefactoringbackend/source/symbolindexer.cpp
index 109e6c5e80a..dd1069736ff 100644
--- a/src/tools/clangrefactoringbackend/source/symbolindexer.cpp
+++ b/src/tools/clangrefactoringbackend/source/symbolindexer.cpp
@@ -29,6 +29,7 @@
 #include "symbolindexertaskqueue.h"
 
 #include <commandlinebuilder.h>
+#include <environment.h>
 
 #include <chrono>
 #include <iostream>
@@ -67,7 +68,8 @@ SymbolIndexer::SymbolIndexer(SymbolIndexerTaskQueueInterface &symbolIndexerTaskQ
                              FileStatusCache &fileStatusCache,
                              Sqlite::TransactionInterface &transactionInterface,
                              ProjectPartsStorageInterface &projectPartsStorage,
-                             ModifiedTimeCheckerInterface<SourceTimeStamps> &modifiedTimeChecker)
+                             ModifiedTimeCheckerInterface<SourceTimeStamps> &modifiedTimeChecker,
+                             const Environment &environment)
     : m_symbolIndexerTaskQueue(symbolIndexerTaskQueue)
     , m_symbolStorage(symbolStorage)
     , m_buildDependencyStorage(buildDependenciesStorage)
@@ -78,6 +80,7 @@ SymbolIndexer::SymbolIndexer(SymbolIndexerTaskQueueInterface &symbolIndexerTaskQ
     , m_transactionInterface(transactionInterface)
     , m_projectPartsStorage(projectPartsStorage)
     , m_modifiedTimeChecker(modifiedTimeChecker)
+    , m_environment(environment)
 {
     pathWatcher.setNotifier(this);
 }
@@ -99,8 +102,10 @@ void SymbolIndexer::updateProjectPart(ProjectPartContainer &&projectPart)
             sourcePathId);
 
         if (!m_modifiedTimeChecker.isUpToDate(dependentTimeStamps)) {
-            auto indexing = [projectPart = std::move(projectPart), sourcePathId, this](
-                                SymbolsCollectorInterface &symbolsCollector) {
+            auto indexing = [projectPart = std::move(projectPart),
+                             sourcePathId,
+                             preIncludeSearchPath = m_environment.preIncludeSearchPath(),
+                             this](SymbolsCollectorInterface &symbolsCollector) {
                 auto collect = [&](const FilePath &pchPath) {
                     using Builder = CommandLineBuilder<ProjectPartContainer, Utils::SmallStringVector>;
                     Builder commandLineBuilder{projectPart,
@@ -108,7 +113,8 @@ void SymbolIndexer::updateProjectPart(ProjectPartContainer &&projectPart)
                                                InputFileType::Source,
                                                {},
                                                {},
-                                               pchPath};
+                                               pchPath,
+                                               preIncludeSearchPath};
                     symbolsCollector.setFile(sourcePathId, commandLineBuilder.commandLine);
 
                     return symbolsCollector.collectSymbols();
@@ -174,13 +180,21 @@ void SymbolIndexer::updateChangedPath(FilePathId filePathId,
 
     SourceTimeStamps dependentTimeStamps = m_symbolStorage.fetchIncludedIndexingTimeStamps(filePathId);
 
-    auto indexing = [optionalArtefact = std::move(optionalArtefact), filePathId, this](
-                        SymbolsCollectorInterface &symbolsCollector) {
+    auto indexing = [optionalArtefact = std::move(optionalArtefact),
+                     filePathId,
+                     preIncludeSearchPath = m_environment.preIncludeSearchPath(),
+                     this](SymbolsCollectorInterface &symbolsCollector) {
         auto collect = [&](const FilePath &pchPath) {
             const ProjectPartArtefact &artefact = *optionalArtefact;
 
             using Builder = CommandLineBuilder<ProjectPartArtefact, Utils::SmallStringVector>;
-            Builder builder{artefact, artefact.toolChainArguments, InputFileType::Source, {}, {}, pchPath};
+            Builder builder{artefact,
+                            artefact.toolChainArguments,
+                            InputFileType::Source,
+                            {},
+                            {},
+                            pchPath,
+                            preIncludeSearchPath};
 
             symbolsCollector.setFile(filePathId, builder.commandLine);
 
diff --git a/src/tools/clangrefactoringbackend/source/symbolindexer.h b/src/tools/clangrefactoringbackend/source/symbolindexer.h
index d574d0e01d8..64b442bf33d 100644
--- a/src/tools/clangrefactoringbackend/source/symbolindexer.h
+++ b/src/tools/clangrefactoringbackend/source/symbolindexer.h
@@ -40,6 +40,7 @@
 namespace ClangBackEnd {
 
 class SymbolsCollectorInterface;
+class Environment;
 
 class SymbolIndexer final : public ClangPathWatcherNotifier
 {
@@ -53,7 +54,8 @@ public:
                   FileStatusCache &fileStatusCache,
                   Sqlite::TransactionInterface &transactionInterface,
                   ProjectPartsStorageInterface &projectPartsStorage,
-                  ModifiedTimeCheckerInterface<SourceTimeStamps> &modifiedTimeChecker);
+                  ModifiedTimeCheckerInterface<SourceTimeStamps> &modifiedTimeChecker,
+                  const Environment &environment);
 
     void updateProjectParts(ProjectPartContainers &&projectParts);
     void updateProjectPart(ProjectPartContainer &&projectPart);
@@ -84,6 +86,7 @@ private:
     Sqlite::TransactionInterface &m_transactionInterface;
     ProjectPartsStorageInterface &m_projectPartsStorage;
     ModifiedTimeCheckerInterface<SourceTimeStamps> &m_modifiedTimeChecker;
+    const Environment &m_environment;
 };
 
 } // namespace ClangBackEnd
diff --git a/src/tools/clangrefactoringbackend/source/symbolindexing.h b/src/tools/clangrefactoringbackend/source/symbolindexing.h
index 10df4e397b0..d4e36499b12 100644
--- a/src/tools/clangrefactoringbackend/source/symbolindexing.h
+++ b/src/tools/clangrefactoringbackend/source/symbolindexing.h
@@ -85,7 +85,8 @@ public:
     SymbolIndexing(Sqlite::Database &database,
                    FilePathCachingInterface &filePathCache,
                    const GeneratedFiles &generatedFiles,
-                   ProgressCounter::SetProgressCallback &&setProgressCallback)
+                   ProgressCounter::SetProgressCallback &&setProgressCallback,
+                   const Environment &environment)
         : m_filePathCache(filePathCache)
         , m_buildDependencyStorage(database)
         , m_precompiledHeaderStorage(database)
@@ -93,6 +94,17 @@ public:
         , m_symbolStorage(database)
         , m_collectorManger(generatedFiles, database)
         , m_progressCounter(std::move(setProgressCallback))
+        , m_indexer(m_indexerQueue,
+                    m_symbolStorage,
+                    m_buildDependencyStorage,
+                    m_precompiledHeaderStorage,
+                    m_sourceWatcher,
+                    m_filePathCache,
+                    m_fileStatusCache,
+                    m_symbolStorage.database,
+                    m_projectPartsStorage,
+                    m_modifiedTimeChecker,
+                    environment)
         , m_indexerScheduler(m_collectorManger,
                              m_indexerQueue,
                              m_progressCounter,
@@ -139,16 +151,7 @@ private:
         }};
     ModifiedTimeChecker<ClangBackEnd::SourceTimeStamps> m_modifiedTimeChecker{getModifiedTime,
                                                                               m_filePathCache};
-    SymbolIndexer m_indexer{m_indexerQueue,
-                            m_symbolStorage,
-                            m_buildDependencyStorage,
-                            m_precompiledHeaderStorage,
-                            m_sourceWatcher,
-                            m_filePathCache,
-                            m_fileStatusCache,
-                            m_symbolStorage.database,
-                            m_projectPartsStorage,
-                            m_modifiedTimeChecker};
+    SymbolIndexer m_indexer;
     SymbolIndexerTaskQueue m_indexerQueue{m_indexerScheduler, m_progressCounter};
     SymbolIndexerTaskScheduler m_indexerScheduler;
 };
diff --git a/tests/unit/mockup/coreplugin/icore.h b/tests/unit/mockup/coreplugin/icore.h
index 579fbc3b56f..8cf88f70376 100644
--- a/tests/unit/mockup/coreplugin/icore.h
+++ b/tests/unit/mockup/coreplugin/icore.h
@@ -12,5 +12,10 @@ inline static QString cacheResourcePath()
     return QDir::tempPath();
 }
 
+inline static QString resourcePath()
+{
+    return QDir::tempPath();
+}
+
 } // namespace ICore
 } // namespace Core
diff --git a/tests/unit/unittest/builddependencycollector-test.cpp b/tests/unit/unittest/builddependencycollector-test.cpp
index 6c2153fe0c4..0d1b9650dce 100644
--- a/tests/unit/unittest/builddependencycollector-test.cpp
+++ b/tests/unit/unittest/builddependencycollector-test.cpp
@@ -737,10 +737,16 @@ TEST_F(BuildDependencyCollector, Create)
         1,
         {},
         {},
-        {{TESTDATA_DIR "/builddependencycollector/system", 1, IncludeSearchPathType::System}},
+        {{TESTDATA_DIR "/builddependencycollector/system",
+          1,
+          ClangBackEnd::IncludeSearchPathType::System}},
         {
-            {TESTDATA_DIR "/builddependencycollector/project", 1, IncludeSearchPathType::User},
-            {TESTDATA_DIR "/builddependencycollector/external", 2, IncludeSearchPathType::User},
+            {TESTDATA_DIR "/builddependencycollector/project",
+             1,
+             ClangBackEnd::IncludeSearchPathType::User},
+            {TESTDATA_DIR "/builddependencycollector/external",
+             2,
+             ClangBackEnd::IncludeSearchPathType::User},
         },
         {
             id(TESTDATA_DIR "/builddependencycollector/project/header1.h"),
@@ -771,6 +777,7 @@ TEST_F(BuildDependencyCollector, Create)
                                  "/builddependencycollector/external/indirect_external2.h"),
                       fileStatus(TESTDATA_DIR "/builddependencycollector/external/external2.h"),
                       fileStatus(TESTDATA_DIR "/builddependencycollector/system/system1.h"),
+                      fileStatus(TESTDATA_DIR "/preincludes/system1.h"),
                       fileStatus(TESTDATA_DIR "/builddependencycollector/system/indirect_system.h"),
                       fileStatus(TESTDATA_DIR
                                  "/builddependencycollector/system/indirect_system2.h"),
@@ -804,7 +811,7 @@ TEST_F(BuildDependencyCollector, Create)
                     HasSource(id(TESTDATA_DIR "/builddependencycollector/external/external2.h"),
                               SourceType::TopProjectInclude),
                     HasSource(id(TESTDATA_DIR "/builddependencycollector/system/system1.h"),
-                              SourceType::TopSystemInclude),
+                              SourceType::SystemInclude),
                     HasSource(id(TESTDATA_DIR "/builddependencycollector/system/indirect_system.h"),
                               SourceType::SystemInclude),
                     HasSource(id(TESTDATA_DIR
@@ -813,7 +820,8 @@ TEST_F(BuildDependencyCollector, Create)
                     HasSource(id(TESTDATA_DIR "/builddependencycollector/project/macros.h"),
                               SourceType::UserInclude),
                     HasSource(id(TESTDATA_DIR "/builddependencycollector/project/generated_file.h"),
-                              SourceType::UserInclude))),
+                              SourceType::UserInclude),
+                    HasSource(id(TESTDATA_DIR "/preincludes/system1.h"), SourceType::TopSystemInclude))),
             Field(&BuildDependency::usedMacros,
                   UnorderedElementsAre(
                       UsedMacro{"IFDEF", id(TESTDATA_DIR "/builddependencycollector/project/macros.h")},
@@ -830,6 +838,7 @@ TEST_F(BuildDependencyCollector, Create)
                       id(TESTDATA_DIR "/builddependencycollector/external/indirect_external2.h"),
                       id(TESTDATA_DIR "/builddependencycollector/external/external2.h"),
                       id(TESTDATA_DIR "/builddependencycollector/system/system1.h"),
+                      id(TESTDATA_DIR "/preincludes/system1.h"),
                       id(TESTDATA_DIR "/builddependencycollector/system/indirect_system.h"),
                       id(TESTDATA_DIR "/builddependencycollector/system/indirect_system2.h"),
                       id(TESTDATA_DIR "/builddependencycollector/project/missingfile.h"),
@@ -854,6 +863,8 @@ TEST_F(BuildDependencyCollector, Create)
                                      id(TESTDATA_DIR
                                         "/builddependencycollector/external/external2.h")),
                     SourceDependency(id(TESTDATA_DIR "/builddependencycollector/project/main4.cpp"),
+                                     id(TESTDATA_DIR "/preincludes/system1.h")),
+                    SourceDependency(id(TESTDATA_DIR "/preincludes/system1.h"),
                                      id(TESTDATA_DIR "/builddependencycollector/system/system1.h")),
                     SourceDependency(id(TESTDATA_DIR "/builddependencycollector/project/main4.cpp"),
                                      id(TESTDATA_DIR "/builddependencycollector/project/macros.h")),
@@ -888,10 +899,16 @@ TEST_F(BuildDependencyCollector, Clear)
         1,
         {},
         {},
-        {{TESTDATA_DIR "/builddependencycollector/system", 1, IncludeSearchPathType::System}},
+        {{TESTDATA_DIR "/builddependencycollector/system",
+          1,
+          ClangBackEnd::IncludeSearchPathType::System}},
         {
-            {TESTDATA_DIR "/builddependencycollector/project", 1, IncludeSearchPathType::User},
-            {TESTDATA_DIR "/builddependencycollector/external", 2, IncludeSearchPathType::User},
+            {TESTDATA_DIR "/builddependencycollector/project",
+             1,
+             ClangBackEnd::IncludeSearchPathType::User},
+            {TESTDATA_DIR "/builddependencycollector/external",
+             2,
+             ClangBackEnd::IncludeSearchPathType::User},
         },
         {
             id(TESTDATA_DIR "/builddependencycollector/project/header1.h"),
@@ -899,14 +916,76 @@ TEST_F(BuildDependencyCollector, Clear)
             id(TESTDATA_DIR "/builddependencycollector/project/missingfile.h"),
             id(TESTDATA_DIR "/builddependencycollector/project/macros.h"),
         },
-        {},
+        {id(TESTDATA_DIR "/builddependencycollector/project/main4.cpp")},
         Utils::Language::Cxx,
         Utils::LanguageVersion::CXX11,
         Utils::LanguageExtension::None};
     collector.create(projectPart);
+    ClangBackEnd::ProjectPartContainer emptyProjectPart{
+        1,
+        {},
+        {},
+        {{TESTDATA_DIR "/builddependencycollector/system",
+          1,
+          ClangBackEnd::IncludeSearchPathType::System}},
+        {
+            {TESTDATA_DIR "/builddependencycollector/project",
+             1,
+             ClangBackEnd::IncludeSearchPathType::User},
+            {TESTDATA_DIR "/builddependencycollector/external",
+             2,
+             ClangBackEnd::IncludeSearchPathType::User},
+        },
+        {
+            id(TESTDATA_DIR "/builddependencycollector/project/header1.h"),
+            id(TESTDATA_DIR "/builddependencycollector/project/header2.h"),
+            id(TESTDATA_DIR "/builddependencycollector/project/missingfile.h"),
+            id(TESTDATA_DIR "/builddependencycollector/project/macros.h"),
+        },
+        {},
+        Utils::Language::Cxx,
+        Utils::LanguageVersion::CXX11,
+        Utils::LanguageExtension::None};
 
-    auto buildDependency = collector.create(projectPart);
+    auto buildDependency = collector.create(emptyProjectPart);
 
     ASSERT_THAT(buildDependency.sources, IsEmpty());
 }
+
+TEST_F(BuildDependencyCollector, PreIncludes)
+{
+    using ClangBackEnd::IncludeSearchPathType;
+    ClangBackEnd::BuildDependencyCollector collector{filePathCache, generatedFiles, environment};
+    ClangBackEnd::ProjectPartContainer projectPart{
+        1,
+        {},
+        {},
+        {{TESTDATA_DIR "/builddependencycollector/system",
+          1,
+          ClangBackEnd::IncludeSearchPathType::System}},
+        {
+            {TESTDATA_DIR "/builddependencycollector/project",
+             1,
+             ClangBackEnd::IncludeSearchPathType::User},
+            {TESTDATA_DIR "/builddependencycollector/external",
+             2,
+             ClangBackEnd::IncludeSearchPathType::User},
+        },
+        {
+            id(TESTDATA_DIR "/builddependencycollector/project/header1.h"),
+            id(TESTDATA_DIR "/builddependencycollector/project/header2.h"),
+            id(TESTDATA_DIR "/builddependencycollector/project/missingfile.h"),
+            id(TESTDATA_DIR "/builddependencycollector/project/macros.h"),
+        },
+        {id(TESTDATA_DIR "/builddependencycollector/project/main4.cpp")},
+        Utils::Language::Cxx,
+        Utils::LanguageVersion::CXX11,
+        Utils::LanguageExtension::None};
+
+    auto buildDependency = collector.create(projectPart);
+
+    ASSERT_THAT(buildDependency.sources,
+                Contains(HasSource(id(TESTDATA_DIR "/preincludes/system1.h"),
+                                   SourceType::TopSystemInclude)));
+}
 } // namespace
diff --git a/tests/unit/unittest/clangfollowsymbol-test.cpp b/tests/unit/unittest/clangfollowsymbol-test.cpp
index 628aa076186..e836cc83c66 100644
--- a/tests/unit/unittest/clangfollowsymbol-test.cpp
+++ b/tests/unit/unittest/clangfollowsymbol-test.cpp
@@ -24,7 +24,7 @@
 ****************************************************************************/
 
 #include "googletest.h"
-#include "testenvironment.h"
+#include "unittest-utility-functions.h"
 
 #include <clangsupport_global.h>
 #include <clangfollowsymboljob.h>
@@ -113,7 +113,7 @@ public:
     ClangBackEnd::UnsavedFiles unsavedFiles;
     ClangBackEnd::Documents documents{unsavedFiles};
     Utf8StringVector compilationArguments{
-        TestEnvironment::addPlatformArguments({Utf8StringLiteral("-std=c++14")})};
+        UnitTest::addPlatformArguments({Utf8StringLiteral("-std=c++14")})};
     Document document = {sourceFilePath, compilationArguments, {}, documents};
     Document headerDocument = {headerFilePath, compilationArguments, {}, documents};
     QVector<Utf8String> deps{sourceFilePath, cursorPath};
diff --git a/tests/unit/unittest/clangreferencescollector-test.cpp b/tests/unit/unittest/clangreferencescollector-test.cpp
index acf7c42ac3d..bb04d8c8d1d 100644
--- a/tests/unit/unittest/clangreferencescollector-test.cpp
+++ b/tests/unit/unittest/clangreferencescollector-test.cpp
@@ -24,7 +24,7 @@
 ****************************************************************************/
 
 #include "googletest.h"
-#include "testenvironment.h"
+#include "unittest-utility-functions.h"
 
 #include <clangsupport_global.h>
 #include <clangreferencescollector.h>
@@ -59,7 +59,7 @@ struct Data {
     ClangBackEnd::UnsavedFiles unsavedFiles;
     ClangBackEnd::Documents documents{unsavedFiles};
     Document document{Utf8StringLiteral(TESTDATA_DIR"/references.cpp"),
-                      TestEnvironment::addPlatformArguments({Utf8StringLiteral("-std=c++14")}),
+                      UnitTest::addPlatformArguments({Utf8StringLiteral("-std=c++14")}),
                       {},
                       documents};
 };
diff --git a/tests/unit/unittest/codecompletionsextractor-test.cpp b/tests/unit/unittest/codecompletionsextractor-test.cpp
index ae7559ce788..509dfd49dc4 100644
--- a/tests/unit/unittest/codecompletionsextractor-test.cpp
+++ b/tests/unit/unittest/codecompletionsextractor-test.cpp
@@ -24,7 +24,7 @@
 ****************************************************************************/
 
 #include "googletest.h"
-#include "testenvironment.h"
+#include "unittest-utility-functions.h"
 
 #include <clangcodecompleteresults.h>
 #include <clangdocument.h>
@@ -148,7 +148,7 @@ protected:
 protected:
     ClangBackEnd::UnsavedFiles unsavedFiles;
     ClangBackEnd::Documents documents{unsavedFiles};
-    Utf8StringVector compilationArguments{TestEnvironment::addPlatformArguments()};
+    Utf8StringVector compilationArguments{UnitTest::addPlatformArguments()};
     Document functionDocument{Utf8StringLiteral(TESTDATA_DIR"/complete_extractor_function.cpp"), compilationArguments, {},  documents};
     Document functionOverloadDocument{Utf8StringLiteral(TESTDATA_DIR"/complete_extractor_functionoverload.cpp"), compilationArguments, {},  documents};
     Document variableDocument{Utf8StringLiteral(TESTDATA_DIR"/complete_extractor_variable.cpp"), compilationArguments, {},  documents};
diff --git a/tests/unit/unittest/commandlinebuilder-test.cpp b/tests/unit/unittest/commandlinebuilder-test.cpp
index d16bb008bbe..c5765037dc5 100644
--- a/tests/unit/unittest/commandlinebuilder-test.cpp
+++ b/tests/unit/unittest/commandlinebuilder-test.cpp
@@ -36,6 +36,7 @@ namespace {
 template<typename ProjectInfo>
 using Builder = ClangBackEnd::CommandLineBuilder<ProjectInfo>;
 
+using ClangBackEnd::FilePath;
 using ClangBackEnd::IncludeSearchPathType;
 using ClangBackEnd::InputFileType;
 
@@ -136,8 +137,6 @@ TYPED_TEST(CommandLineBuilder, CHeader)
                             "c-header",
                             "-std=c11",
                             "-nostdinc",
-                            "-I",
-                            toNativePath(resourcePath()),
                             toNativePath("/source/file.c")));
 }
 
@@ -156,8 +155,6 @@ TYPED_TEST(CommandLineBuilder, CSource)
                             "c",
                             "-std=c11",
                             "-nostdinc",
-                            "-I",
-                            toNativePath(resourcePath()),
                             toNativePath("/source/file.c")));
 }
 
@@ -177,8 +174,6 @@ TYPED_TEST(CommandLineBuilder, ObjectiveCHeader)
                             "objective-c-header",
                             "-std=c11",
                             "-nostdinc",
-                            "-I",
-                            toNativePath(resourcePath()),
                             toNativePath("/source/file.c")));
 }
 
@@ -198,8 +193,6 @@ TYPED_TEST(CommandLineBuilder, ObjectiveCSource)
                             "objective-c",
                             "-std=c11",
                             "-nostdinc",
-                            "-I",
-                            toNativePath(resourcePath()),
                             toNativePath("/source/file.c")));
 }
 
@@ -219,8 +212,6 @@ TYPED_TEST(CommandLineBuilder, CppHeader)
                             "-std=c++98",
                             "-nostdinc",
                             "-nostdinc++",
-                            "-I",
-                            toNativePath(resourcePath()),
                             toNativePath("/source/file.cpp")));
 }
 
@@ -240,8 +231,6 @@ TYPED_TEST(CommandLineBuilder, CppSource)
                             "-std=c++98",
                             "-nostdinc",
                             "-nostdinc++",
-                            "-I",
-                            toNativePath(resourcePath()),
                             toNativePath("/source/file.cpp")));
 }
 
@@ -262,8 +251,6 @@ TYPED_TEST(CommandLineBuilder, ObjectiveCppHeader)
                             "-std=c++98",
                             "-nostdinc",
                             "-nostdinc++",
-                            "-I",
-                            toNativePath(resourcePath()),
                             toNativePath("/source/file.cpp")));
 }
 
@@ -284,8 +271,6 @@ TYPED_TEST(CommandLineBuilder, ObjectiveCppSource)
                             "-std=c++98",
                             "-nostdinc",
                             "-nostdinc++",
-                            "-I",
-                            toNativePath(resourcePath()),
                             toNativePath("/source/file.cpp")));
 }
 
@@ -509,7 +494,13 @@ TYPED_TEST(CommandLineBuilder, IncludesOrder)
                                           {"/system/foo", 3, IncludeSearchPathType::Framework},
                                           {"/builtin/bar", 2, IncludeSearchPathType::BuiltIn},
                                           {"/builtin/foo", 1, IncludeSearchPathType::BuiltIn}};
-    Builder<TypeParam> builder{this->emptyProjectInfo, {}, InputFileType::Header, "/source/file.cpp"};
+    Builder<TypeParam> builder{this->emptyProjectInfo,
+                               {},
+                               InputFileType::Header,
+                               "/source/file.cpp",
+                               {},
+                               {},
+                               ClangBackEnd::NativeFilePath{FilePath{"/resource/path"}}};
 
     ASSERT_THAT(builder.commandLine,
                 ElementsAre("clang++",
@@ -520,8 +511,8 @@ TYPED_TEST(CommandLineBuilder, IncludesOrder)
                             "-std=c++11",
                             "-nostdinc",
                             "-nostdinc++",
-                            "-I",
-                            toNativePath(resourcePath()),
+                            "-isystem",
+                            toNativePath("/resource/path"),
                             "-I",
                             toNativePath("/include/foo"),
                             "-I",
@@ -549,9 +540,7 @@ TYPED_TEST(CommandLineBuilder, EmptySourceFile)
                             "c++-header",
                             "-std=c++98",
                             "-nostdinc",
-                            "-nostdinc++",
-                            "-I",
-                            toNativePath(resourcePath())));
+                            "-nostdinc++"));
 }
 
 TYPED_TEST(CommandLineBuilder, SourceFile)
@@ -567,8 +556,6 @@ TYPED_TEST(CommandLineBuilder, SourceFile)
                             "-std=c++98",
                             "-nostdinc",
                             "-nostdinc++",
-                            "-I",
-                            toNativePath(resourcePath()),
                             toNativePath("/source/file.cpp")));
 }
 
@@ -586,8 +573,6 @@ TYPED_TEST(CommandLineBuilder, EmptyOutputFile)
                             "-std=c++98",
                             "-nostdinc",
                             "-nostdinc++",
-                            "-I",
-                            toNativePath(resourcePath()),
                             toNativePath("/source/file.cpp")));
 }
 
@@ -608,13 +593,24 @@ TYPED_TEST(CommandLineBuilder, OutputFile)
                             "-std=c++98",
                             "-nostdinc",
                             "-nostdinc++",
-                            "-I",
-                            toNativePath(resourcePath()),
                             "-o",
                             toNativePath("/output/file.o"),
                             toNativePath("/source/file.cpp")));
 }
 
+TYPED_TEST(CommandLineBuilder, PreIncludeSearchPath)
+{
+    Builder<TypeParam> builder{this->emptyProjectInfo,
+                               {},
+                               {},
+                               {},
+                               {},
+                               {},
+                               ClangBackEnd::NativeFilePath{FilePath{"/resource/path"}}};
+
+    ASSERT_THAT(builder.commandLine, Contains(toNativePath("/resource/path")));
+}
+
 TYPED_TEST(CommandLineBuilder, IncludePchPath)
 {
     Builder<TypeParam> builder{this->emptyProjectInfo,
@@ -633,8 +629,6 @@ TYPED_TEST(CommandLineBuilder, IncludePchPath)
                             "-std=c++98",
                             "-nostdinc",
                             "-nostdinc++",
-                            "-I",
-                            toNativePath(resourcePath()),
                             "-Xclang",
                             "-include-pch",
                             "-Xclang",
@@ -660,9 +654,7 @@ TYPED_TEST(CommandLineBuilder, CompilerMacros)
                             "-nostdinc",
                             "-nostdinc++",
                             "-DER=2",
-                            "-DYI=1",
-                            "-I",
-                            toNativePath(resourcePath())));
+                            "-DYI=1"));
 }
 
 } // namespace
diff --git a/tests/unit/unittest/cursor-test.cpp b/tests/unit/unittest/cursor-test.cpp
index e55668d420c..2fa4bff7098 100644
--- a/tests/unit/unittest/cursor-test.cpp
+++ b/tests/unit/unittest/cursor-test.cpp
@@ -26,7 +26,7 @@
 #include "googletest.h"
 
 #include "clangcompareoperators.h"
-#include "testenvironment.h"
+#include "unittest-utility-functions.h"
 
 #include <clangdocument.h>
 #include <clangdocuments.h>
@@ -63,7 +63,7 @@ struct Data {
     ClangBackEnd::Documents documents{unsavedFiles};
     Utf8String filePath{Utf8StringLiteral(TESTDATA_DIR"/cursor.cpp")};
     Document document{filePath,
-                      TestEnvironment::addPlatformArguments({Utf8StringLiteral("-std=c++11")}),
+                      UnitTest::addPlatformArguments({Utf8StringLiteral("-std=c++11")}),
                       {},
                       documents};
     TranslationUnit translationUnit{filePath,
diff --git a/tests/unit/unittest/data/preincludes/system1.h b/tests/unit/unittest/data/preincludes/system1.h
new file mode 100644
index 00000000000..005a65916e3
--- /dev/null
+++ b/tests/unit/unittest/data/preincludes/system1.h
@@ -0,0 +1 @@
+#include_next <system1.h>
diff --git a/tests/unit/unittest/diagnostic-test.cpp b/tests/unit/unittest/diagnostic-test.cpp
index fac44162cd0..3ab382c46b0 100644
--- a/tests/unit/unittest/diagnostic-test.cpp
+++ b/tests/unit/unittest/diagnostic-test.cpp
@@ -23,10 +23,10 @@
 **
 ****************************************************************************/
 
-#include "googletest.h"
 #include "diagnosticcontainer-matcher.h"
+#include "googletest.h"
 #include "rundocumentparse-utility.h"
-#include "testenvironment.h"
+#include "unittest-utility-functions.h"
 
 #include <diagnostic.h>
 #include <diagnosticcontainer.h>
@@ -87,7 +87,7 @@ protected:
     ClangBackEnd::UnsavedFiles unsavedFiles;
     ClangBackEnd::Documents documents{unsavedFiles};
     Document document{Utf8StringLiteral(TESTDATA_DIR"/diagnostic_diagnostic.cpp"),
-                      TestEnvironment::addPlatformArguments({Utf8StringLiteral("-std=c++11")}),
+                      UnitTest::addPlatformArguments({Utf8StringLiteral("-std=c++11")}),
                       {},
                       documents};
     UnitTest::RunDocumentParse _1{document};
diff --git a/tests/unit/unittest/diagnosticset-test.cpp b/tests/unit/unittest/diagnosticset-test.cpp
index f37d00e13fb..b59325e0e71 100644
--- a/tests/unit/unittest/diagnosticset-test.cpp
+++ b/tests/unit/unittest/diagnosticset-test.cpp
@@ -23,9 +23,9 @@
 **
 ****************************************************************************/
 
-#include "googletest.h"
 #include "diagnosticcontainer-matcher.h"
-#include "testenvironment.h"
+#include "googletest.h"
+#include "unittest-utility-functions.h"
 
 #include <clangsupport_global.h>
 #include <clangdocument.h>
@@ -64,7 +64,7 @@ protected:
     ClangBackEnd::UnsavedFiles unsavedFiles;
     ClangBackEnd::Documents documents{unsavedFiles};
     Utf8StringVector compilationArguments{
-        TestEnvironment::addPlatformArguments({Utf8StringLiteral("-pedantic")})};
+        UnitTest::addPlatformArguments({Utf8StringLiteral("-pedantic")})};
     Document document{Utf8StringLiteral(TESTDATA_DIR "/diagnostic_diagnosticset.cpp"),
                       compilationArguments,
                       {},
diff --git a/tests/unit/unittest/highlightingresultreporter-test.cpp b/tests/unit/unittest/highlightingresultreporter-test.cpp
index dfe8dfbd2e0..dd2001e02ff 100644
--- a/tests/unit/unittest/highlightingresultreporter-test.cpp
+++ b/tests/unit/unittest/highlightingresultreporter-test.cpp
@@ -24,7 +24,7 @@
 ****************************************************************************/
 
 #include "googletest.h"
-#include "testenvironment.h"
+#include "unittest-utility-functions.h"
 
 #include <chunksreportedmonitor.h>
 #include <clangdocument.h>
@@ -51,7 +51,7 @@ struct Data {
     UnsavedFiles unsavedFiles;
     Documents documents{unsavedFiles};
     Document document{Utf8StringLiteral(TESTDATA_DIR "/highlightingmarks.cpp"),
-                      TestEnvironment::addPlatformArguments({Utf8StringLiteral("-std=c++14")}),
+                      UnitTest::addPlatformArguments({Utf8StringLiteral("-std=c++14")}),
                       Utf8StringVector(),
                       documents};
 };
diff --git a/tests/unit/unittest/pchcreator-test.cpp b/tests/unit/unittest/pchcreator-test.cpp
index 9c40b7fea76..19bc087ca6d 100644
--- a/tests/unit/unittest/pchcreator-test.cpp
+++ b/tests/unit/unittest/pchcreator-test.cpp
@@ -27,6 +27,7 @@
 
 #include "fakeprocess.h"
 #include "filesystem-utilities.h"
+#include "testenvironment.h"
 
 #include "mockbuilddependenciesstorage.h"
 #include "mockclangpathwatcher.h"
@@ -79,7 +80,11 @@ MATCHER_P2(HasIdAndType,
 class PchCreator: public ::testing::Test
 {
 protected:
-    PchCreator() { creator.setUnsavedFiles({generatedFile}); }
+    PchCreator()
+    {
+        creator.setUnsavedFiles({generatedFile});
+        pchTask1.preIncludeSearchPath = testEnvironment.preIncludeSearchPath();
+    }
 
     ClangBackEnd::FilePathId id(ClangBackEnd::FilePathView path)
     {
@@ -121,6 +126,7 @@ protected:
          {TESTDATA_DIR "/builddependencycollector/external", 1, IncludeSearchPathType::System}},
         {{TESTDATA_DIR "/builddependencycollector/project", 1, IncludeSearchPathType::User}},
     };
+    TestEnvironment testEnvironment;
 };
 using PchCreatorSlowTest = PchCreator;
 using PchCreatorVerySlowTest = PchCreator;
@@ -148,8 +154,8 @@ TEST_F(PchCreator, CreateProjectPartClangCompilerArguments)
                             "-std=c++98",
                             "-nostdinc",
                             "-nostdinc++",
-                            "-I",
-                            toNativePath(resourcePath()),
+                            "-isystem",
+                            toNativePath(TESTDATA_DIR "/preincludes"),
                             "-I",
                             toNativePath(TESTDATA_DIR "/builddependencycollector/project"),
                             "-isystem",
@@ -175,8 +181,8 @@ TEST_F(PchCreator, CreateProjectPartClangCompilerArgumentsWithSystemPch)
                             "-std=c++98",
                             "-nostdinc",
                             "-nostdinc++",
-                            "-I",
-                            toNativePath(resourcePath()),
+                            "-isystem",
+                            toNativePath(TESTDATA_DIR "/preincludes"),
                             "-I",
                             toNativePath(TESTDATA_DIR "/builddependencycollector/project"),
                             "-isystem",
diff --git a/tests/unit/unittest/pchtaskqueue-test.cpp b/tests/unit/unittest/pchtaskqueue-test.cpp
index 4a8c0862eef..0851224d9d0 100644
--- a/tests/unit/unittest/pchtaskqueue-test.cpp
+++ b/tests/unit/unittest/pchtaskqueue-test.cpp
@@ -29,6 +29,7 @@
 #include "mockprecompiledheaderstorage.h"
 #include "mocksqlitetransactionbackend.h"
 #include "mocktaskscheduler.h"
+#include "testenvironment.h"
 
 #include <pchtaskqueue.h>
 #include <progresscounter.h>
@@ -50,11 +51,13 @@ protected:
     MockSqliteTransactionBackend mockSqliteTransactionBackend;
     NiceMock<MockFunction<void(int, int)>> mockSetProgressCallback;
     ClangBackEnd::ProgressCounter progressCounter{mockSetProgressCallback.AsStdFunction()};
+    TestEnvironment testEnvironment;
     ClangBackEnd::PchTaskQueue queue{mockSytemPchTaskScheduler,
                                      mockProjectPchTaskScheduler,
                                      progressCounter,
                                      mockPrecompiledHeaderStorage,
-                                     mockSqliteTransactionBackend};
+                                     mockSqliteTransactionBackend,
+                                     testEnvironment};
     IncludeSearchPaths systemIncludeSearchPaths{
         {"/includes", 1, IncludeSearchPathType::BuiltIn},
         {"/other/includes", 2, IncludeSearchPathType::System}};
@@ -297,6 +300,7 @@ TEST_F(PchTaskQueue, CreateProjectTaskFromPchTask)
     auto tasks = queue.createProjectTasks({projectTask1});
     auto projectTask = projectTask1;
     projectTask.systemPchPath = "/path/to/pch";
+    projectTask.preIncludeSearchPath = testEnvironment.preIncludeSearchPath();
 
     EXPECT_CALL(mockPrecompiledHeaderStorage, fetchSystemPrecompiledHeaderPath(Eq(1)))
         .WillOnce(Return(ClangBackEnd::FilePath{"/path/to/pch"}));
@@ -316,6 +320,7 @@ TEST_F(PchTaskQueue, DeleteProjectPchEntryInDatabaseIfNoPchIsGenerated)
     auto tasks = queue.createProjectTasks({projectTask1});
     auto projectTask = projectTask1;
     projectTask.systemPchPath = "/path/to/pch";
+    projectTask.preIncludeSearchPath = testEnvironment.preIncludeSearchPath();
 
     EXPECT_CALL(mockPrecompiledHeaderStorage, fetchSystemPrecompiledHeaderPath(Eq(1)))
         .WillOnce(Return(ClangBackEnd::FilePath{"/path/to/pch"}));
@@ -355,8 +360,10 @@ TEST_F(PchTaskQueue, CreateSystemTaskFromPchTask)
     MockPchCreator mockPchCreator;
     ClangBackEnd::ProjectPartPch projectPartPch{{}, "/path/to/pch", 99};
     auto tasks = queue.createSystemTasks({systemTask4});
+    auto systemTask = systemTask4;
+    systemTask.preIncludeSearchPath = testEnvironment.preIncludeSearchPath();
 
-    EXPECT_CALL(mockPchCreator, generatePch(Eq(systemTask4)));
+    EXPECT_CALL(mockPchCreator, generatePch(Eq(systemTask)));
     EXPECT_CALL(mockPchCreator, projectPartPch()).WillOnce(ReturnRef(projectPartPch));
     EXPECT_CALL(mockPrecompiledHeaderStorage,
                 insertSystemPrecompiledHeaders(UnorderedElementsAre(1, 3), Eq("/path/to/pch"), 99));
@@ -370,8 +377,10 @@ TEST_F(PchTaskQueue, DeleteSystemPchEntryInDatabaseIfNoPchIsGenerated)
     MockPchCreator mockPchCreator;
     ClangBackEnd::ProjectPartPch projectPartPch{{}, "", 0};
     auto tasks = queue.createSystemTasks({systemTask4});
+    auto systemTask = systemTask4;
+    systemTask.preIncludeSearchPath = testEnvironment.preIncludeSearchPath();
 
-    EXPECT_CALL(mockPchCreator, generatePch(Eq(systemTask4)));
+    EXPECT_CALL(mockPchCreator, generatePch(Eq(systemTask)));
     EXPECT_CALL(mockPchCreator, projectPartPch()).WillOnce(ReturnRef(projectPartPch));
     EXPECT_CALL(mockPrecompiledHeaderStorage,
                 deleteSystemPrecompiledHeaders(UnorderedElementsAre(1, 3)));
diff --git a/tests/unit/unittest/projectupdater-test.cpp b/tests/unit/unittest/projectupdater-test.cpp
index 21ee3f5781e..494eed57139 100644
--- a/tests/unit/unittest/projectupdater-test.cpp
+++ b/tests/unit/unittest/projectupdater-test.cpp
@@ -351,7 +351,6 @@ TEST_F(ProjectUpdater, ToolChainArguments)
 
     ASSERT_THAT(arguments,
                 ElementsAre(QString{"-m32"},
-                            QString{"-fPIC"},
                             QString{"extraflags"},
                             QString{"-include"},
                             QString{"config.h"}));
diff --git a/tests/unit/unittest/skippedsourceranges-test.cpp b/tests/unit/unittest/skippedsourceranges-test.cpp
index 083f795ec95..fd95dc47797 100644
--- a/tests/unit/unittest/skippedsourceranges-test.cpp
+++ b/tests/unit/unittest/skippedsourceranges-test.cpp
@@ -24,7 +24,7 @@
 ****************************************************************************/
 
 #include "googletest.h"
-#include "testenvironment.h"
+#include "unittest-utility-functions.h"
 
 #include <cursor.h>
 #include <clangdocument.h>
@@ -89,7 +89,7 @@ struct Data {
     ClangBackEnd::UnsavedFiles unsavedFiles;
     ClangBackEnd::Documents documents{unsavedFiles};
     Utf8String filePath = Utf8StringLiteral(TESTDATA_DIR"/skippedsourceranges.cpp");
-    Utf8StringVector compilationArguments{TestEnvironment::addPlatformArguments(
+    Utf8StringVector compilationArguments{UnitTest::addPlatformArguments(
         {Utf8StringLiteral("-std=c++11"), {}, Utf8StringLiteral("-DBLAH")})};
     Document document{filePath, compilationArguments, {}, documents};
     TranslationUnit translationUnit{filePath,
diff --git a/tests/unit/unittest/sourcerange-test.cpp b/tests/unit/unittest/sourcerange-test.cpp
index c66b9854dbc..1b2b44a8f90 100644
--- a/tests/unit/unittest/sourcerange-test.cpp
+++ b/tests/unit/unittest/sourcerange-test.cpp
@@ -25,7 +25,7 @@
 
 #include "googletest.h"
 #include "rundocumentparse-utility.h"
-#include "testenvironment.h"
+#include "unittest-utility-functions.h"
 
 #include <clangtranslationunit.h>
 #include <diagnostic.h>
@@ -75,7 +75,7 @@ struct Data {
     ClangBackEnd::Documents documents{unsavedFiles};
     Utf8String filePath{Utf8StringLiteral(TESTDATA_DIR"/diagnostic_source_range.cpp")};
     Document document{filePath,
-                      {TestEnvironment::addPlatformArguments({Utf8StringLiteral("-pedantic")})},
+                      {UnitTest::addPlatformArguments({Utf8StringLiteral("-pedantic")})},
                       {},
                       documents};
     UnitTest::RunDocumentParse _1{document};
diff --git a/tests/unit/unittest/symbolindexer-test.cpp b/tests/unit/unittest/symbolindexer-test.cpp
index c1373e03c45..35943235325 100644
--- a/tests/unit/unittest/symbolindexer-test.cpp
+++ b/tests/unit/unittest/symbolindexer-test.cpp
@@ -34,6 +34,7 @@
 #include "mocksqlitetransactionbackend.h"
 #include "mocksymbolscollector.h"
 #include "mocksymbolstorage.h"
+#include "testenvironment.h"
 
 #include <filepathcaching.h>
 #include <filestatuscache.h>
@@ -254,6 +255,7 @@ protected:
     NiceMock<MockFunction<void(int, int)>> mockSetProgressCallback;
     ClangBackEnd::ProgressCounter progressCounter{mockSetProgressCallback.AsStdFunction()};
     NiceMock<MockSourceTimeStampsModifiedTimeChecker> mockModifiedTimeChecker;
+    TestEnvironment testEnvironment;
     ClangBackEnd::SymbolIndexer indexer{indexerQueue,
                                         mockSymbolStorage,
                                         mockBuildDependenciesStorage,
@@ -263,7 +265,8 @@ protected:
                                         fileStatusCache,
                                         mockSqliteTransactionBackend,
                                         mockProjectPartsStorage,
-                                        mockModifiedTimeChecker};
+                                        mockModifiedTimeChecker,
+                                        testEnvironment};
     SymbolIndexerTaskQueue indexerQueue{indexerScheduler, progressCounter};
     Scheduler indexerScheduler{collectorManger,
                                indexerQueue,
@@ -290,8 +293,8 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsAddFilesInCollector)
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -324,8 +327,8 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsAddFilesWithPrecompiledHeaderInColl
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -362,8 +365,8 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsAddFilesWithoutPrecompiledHeaderInC
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -402,7 +405,7 @@ TEST_F(SymbolIndexer, UpdateProjectPartsDoesNotCallAddFilesInCollectorForEmptyEv
 
 TEST_F(SymbolIndexer, UpdateProjectPartsCallscollectSymbolsInCollector)
 {
-    EXPECT_CALL(mockCollector, collectSymbols()).Times(2);;
+    EXPECT_CALL(mockCollector, collectSymbols()).Times(2);
 
     indexer.updateProjectParts({projectPart1, projectPart2});
 }
@@ -453,8 +456,8 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsInOrder)
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -492,8 +495,8 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsGetsProjectAndSystemPchPathsAndHasN
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -534,8 +537,8 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsGetsProjectAndSystemPchPathsAndHasE
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -565,8 +568,8 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsGetsProjectAndSystemPchPathsAndHasE
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -608,8 +611,8 @@ TEST_F(SymbolIndexer,
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -639,8 +642,8 @@ TEST_F(SymbolIndexer,
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -670,8 +673,8 @@ TEST_F(SymbolIndexer,
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -707,8 +710,8 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsGetsProjectAndSystemPchPathsAndHasO
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -738,8 +741,8 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsGetsProjectAndSystemPchPathsAndHasO
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -769,8 +772,8 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsGetsProjectAndSystemPchPathsAndHasO
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -806,8 +809,8 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsGetsSystemPchPathsAndHasErrorWithPr
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -847,8 +850,8 @@ TEST_F(SymbolIndexer, UpdateProjectPartsCallsGetsNoPchPathsAndHasErrors)
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -931,7 +934,8 @@ TEST_F(SymbolIndexer, CallSetNotifier)
                                         fileStatusCache,
                                         mockSqliteTransactionBackend,
                                         mockProjectPartsStorage,
-                                        mockModifiedTimeChecker};
+                                        mockModifiedTimeChecker,
+                                        testEnvironment};
 }
 
 TEST_F(SymbolIndexer, PathChangedCallsFetchProjectPartArtefactInStorage)
@@ -1013,8 +1017,8 @@ TEST_F(SymbolIndexer, UpdateChangedPathCallsInOrder)
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -1073,8 +1077,8 @@ TEST_F(SymbolIndexer, PathsChangedCallsGetsProjectAndSystemPchPathsAndHasNoError
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -1118,8 +1122,8 @@ TEST_F(SymbolIndexer, PathsChangedCallsGetsProjectAndSystemPchPathsAndHasErrorWi
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -1149,8 +1153,8 @@ TEST_F(SymbolIndexer, PathsChangedCallsGetsProjectAndSystemPchPathsAndHasErrorWi
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -1194,8 +1198,8 @@ TEST_F(SymbolIndexer, PathsChangedCallsGetsProjectAndSystemPchPathsAndHasErrorWi
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -1225,8 +1229,8 @@ TEST_F(SymbolIndexer, PathsChangedCallsGetsProjectAndSystemPchPathsAndHasErrorWi
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -1256,8 +1260,8 @@ TEST_F(SymbolIndexer, PathsChangedCallsGetsProjectAndSystemPchPathsAndHasErrorWi
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -1296,8 +1300,8 @@ TEST_F(SymbolIndexer, PathsChangedCallsGetsProjectAndSystemPchPathsAndHasOnlyErr
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -1327,8 +1331,8 @@ TEST_F(SymbolIndexer, PathsChangedCallsGetsProjectAndSystemPchPathsAndHasOnlyErr
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -1358,8 +1362,8 @@ TEST_F(SymbolIndexer, PathsChangedCallsGetsProjectAndSystemPchPathsAndHasOnlyErr
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -1398,8 +1402,8 @@ TEST_F(SymbolIndexer, PathsChangedCallsGetsSystemPchPathsAndHasErrorWithProjectP
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -1442,8 +1446,8 @@ TEST_F(SymbolIndexer, PathsChangedCallsGetsNoPchPathsAndHasErrors)
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -1482,8 +1486,8 @@ TEST_F(SymbolIndexer, UpdateChangedPathIsUsingPrecompiledHeader)
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
@@ -1521,8 +1525,8 @@ TEST_F(SymbolIndexer, UpdateChangedPathIsNotUsingPrecompiledHeaderIfItNotExists)
                                     "-nostdinc++",
                                     "-DBAR=1",
                                     "-DFOO=1",
-                                    "-I",
-                                    toNativePath(resourcePath()),
+                                    "-isystem",
+                                    toNativePath(TESTDATA_DIR "/preincludes"),
                                     "-I",
                                     toNativePath("/project/includes"),
                                     "-I",
diff --git a/tests/unit/unittest/symbolindexing-test.cpp b/tests/unit/unittest/symbolindexing-test.cpp
index 6e094951f34..67411efd370 100644
--- a/tests/unit/unittest/symbolindexing-test.cpp
+++ b/tests/unit/unittest/symbolindexing-test.cpp
@@ -24,6 +24,7 @@
 ****************************************************************************/
 
 #include "googletest.h"
+#include "testenvironment.h"
 
 #include <symbolindexing.h>
 #include <symbolquery.h>
@@ -85,7 +86,12 @@ protected:
     ClangBackEnd::GeneratedFiles generatedFiles;
     NiceMock<MockFunction<void(int, int)>> mockSetProgressCallback;
     ClangBackEnd::ProjectPartsStorage<Sqlite::Database> projectPartStorage{database};
-    ClangBackEnd::SymbolIndexing indexing{database, filePathCache, generatedFiles, mockSetProgressCallback.AsStdFunction()};
+    TestEnvironment testEnvironment;
+    ClangBackEnd::SymbolIndexing indexing{database,
+                                          filePathCache,
+                                          generatedFiles,
+                                          mockSetProgressCallback.AsStdFunction(),
+                                          testEnvironment};
     StatementFactory queryFactory{database};
     Query query{queryFactory};
     PathString main1Path = TESTDATA_DIR "/symbolindexing_main1.cpp";
diff --git a/tests/unit/unittest/testenvironment.h b/tests/unit/unittest/testenvironment.h
index a9529c58d55..1e6c7da862c 100644
--- a/tests/unit/unittest/testenvironment.h
+++ b/tests/unit/unittest/testenvironment.h
@@ -27,36 +27,24 @@
 
 #include <environment.h>
 
-#include <utf8string.h>
-#include <utils/hostosinfo.h>
+#include <filepath.h>
 
 #include <QTemporaryDir>
-#include <QVector>
 
 class TestEnvironment final : public ClangBackEnd::Environment
 {
 public:
-    TestEnvironment() {
-        temporaryDirectory.setAutoRemove(true);
-    }
-    QString pchBuildDirectory() const override
-    {
-        return temporaryDirectory.path();
-    }
-
-    uint hardwareConcurrency() const
-    {
-        return 2;
-    }
+    TestEnvironment() { temporaryDirectory.setAutoRemove(true); }
 
-    static QVector<Utf8String> addPlatformArguments(std::initializer_list<Utf8String> arguments = {})
+    Utils::PathString pchBuildDirectory() const override { return temporaryDirectory.path(); }
+    uint hardwareConcurrency() const { return 2; }
+    ClangBackEnd::NativeFilePathView preIncludeSearchPath() const override
     {
-        QVector<Utf8String> result{arguments};
-        if (Utils::HostOsInfo::isWindowsHost())
-            result.append(Utf8StringLiteral("-fno-delayed-template-parsing"));
-        return result;
+        return includeSearchPath;
     }
 
 private:
     QTemporaryDir temporaryDirectory;
+    ClangBackEnd::NativeFilePath includeSearchPath{
+        ClangBackEnd::FilePath{TESTDATA_DIR "/preincludes"}};
 };
diff --git a/tests/unit/unittest/token-test.cpp b/tests/unit/unittest/token-test.cpp
index 3f7c39ea5f3..f5f8a36e3a9 100644
--- a/tests/unit/unittest/token-test.cpp
+++ b/tests/unit/unittest/token-test.cpp
@@ -25,7 +25,7 @@
 
 #include "googletest.h"
 
-#include "testenvironment.h"
+#include "unittest-utility-functions.h"
 
 #include <clangdocument.h>
 #include <clangdocuments.h>
@@ -55,7 +55,7 @@ struct Data {
     ClangBackEnd::Documents documents{unsavedFiles};
     Utf8String filePath{Utf8StringLiteral(TESTDATA_DIR"/token.cpp")};
     Utf8StringVector compilationArguments{
-        TestEnvironment::addPlatformArguments({Utf8StringLiteral("-std=c++11")})};
+        UnitTest::addPlatformArguments({Utf8StringLiteral("-std=c++11")})};
     Document document{filePath, compilationArguments, {}, documents};
     TranslationUnit translationUnit{filePath,
                                     filePath,
diff --git a/tests/unit/unittest/tokenprocessor-test.cpp b/tests/unit/unittest/tokenprocessor-test.cpp
index c96650472d0..285c6d3446f 100644
--- a/tests/unit/unittest/tokenprocessor-test.cpp
+++ b/tests/unit/unittest/tokenprocessor-test.cpp
@@ -24,7 +24,7 @@
 ****************************************************************************/
 
 #include "googletest.h"
-#include "testenvironment.h"
+#include "unittest-utility-functions.h"
 
 #include <clangdocument.h>
 #include <clangdocuments.h>
@@ -128,7 +128,7 @@ struct Data {
     ClangBackEnd::Documents documents{unsavedFiles};
     Utf8String filePath{Utf8StringLiteral(TESTDATA_DIR"/highlightingmarks.cpp")};
     Document document{filePath,
-                      TestEnvironment::addPlatformArguments(
+                      UnitTest::addPlatformArguments(
                           {Utf8StringLiteral("-std=c++14"),
                            Utf8StringLiteral("-I" TESTDATA_DIR)}),
                       {},
diff --git a/tests/unit/unittest/unittest-utility-functions.h b/tests/unit/unittest/unittest-utility-functions.h
index 6d68c1adfcc..5102769e78f 100644
--- a/tests/unit/unittest/unittest-utility-functions.h
+++ b/tests/unit/unittest/unittest-utility-functions.h
@@ -25,10 +25,12 @@
 
 #pragma once
 
+#include <utils/hostosinfo.h>
 #include <utils/smallstring.h>
-
 #include <utils/temporarydirectory.h>
 
+#include <utf8stringvector.h>
+
 inline
 bool operator==(const QString &first, const char *second)
 {
@@ -42,4 +44,12 @@ Utils::PathString temporaryDirPath()
 {
     return Utils::PathString::fromQString(Utils::TemporaryDirectory::masterDirectoryPath());
 }
+
+inline QVector<Utf8String> addPlatformArguments(std::initializer_list<Utf8String> arguments = {})
+{
+    QVector<Utf8String> result{arguments};
+    if (Utils::HostOsInfo::isWindowsHost())
+        result.append(Utf8StringLiteral("-fno-delayed-template-parsing"));
+    return result;
+}
 } // namespace UnitTest