logic: only use precompiled headers for compilation database commands that specify the "-include-pch" flag (issue #719)

src/lib_cxx/project/SourceGroupCxxCdb.cpp

@@ -101,7 +101,8 @@ std::shared_ptr<IndexerCommandProvider> SourceGroupCxxCdb::getIndexerCommandProv
 
 	std::vector<std::wstring> compilerFlags = getBaseCompilerFlags();
 	utility::append(compilerFlags, m_settings->getCompilerFlags());
-	utility::append(compilerFlags, utility::getIncludePchFlags(m_settings.get()));
+
+	const std::vector<std::wstring> includePchFlags = utility::getIncludePchFlags(m_settings.get());
 
 	const std::set<FilePath> indexedHeaderPaths = utility::toSet(m_settings->getIndexedHeaderPathsExpandedAndAbsolute());
 	const std::set<FilePathFilter> excludeFilters = utility::toSet(m_settings->getExcludeFiltersExpandedAndAbsolute());
@@ -122,13 +123,17 @@ std::shared_ptr<IndexerCommandProvider> SourceGroupCxxCdb::getIndexerCommandProv
 		if (filesToIndex.find(sourcePath) != filesToIndex.end() &&
 			sourceFilePaths.find(sourcePath) != sourceFilePaths.end())
 		{
-			std::vector<std::wstring> mergedCompilerFlags;
-			mergedCompilerFlags.reserve(compilerFlags.size() + command.CommandLine.size());
-			for (const std::string& arg : command.CommandLine)
+			std::vector<std::wstring> cdbFlags = utility::convert<std::string, std::wstring>(
+				command.CommandLine,
+				[](const std::string& s) { return utility::decodeFromUtf8(s); }
+			);
+
+			utility::removeIncludePchFlag(cdbFlags);
+
+			if (command.CommandLine.size() != cdbFlags.size())
 			{
-				mergedCompilerFlags.emplace_back(utility::decodeFromUtf8(arg));
+				utility::append(cdbFlags, includePchFlags);
 			}
-			mergedCompilerFlags.insert(mergedCompilerFlags.end(), compilerFlags.begin(), compilerFlags.end());
 
 			provider->addCommand(std::make_shared<IndexerCommandCxx>(
 				sourcePath,
@@ -136,7 +141,7 @@ std::shared_ptr<IndexerCommandProvider> SourceGroupCxxCdb::getIndexerCommandProv
 				excludeFilters,
 				std::set<FilePathFilter>(),
 				FilePath(utility::decodeFromUtf8(command.Directory)),
-				mergedCompilerFlags
+				utility::concat(cdbFlags, compilerFlags)
 			));
 		}
 	}

src/lib_cxx/project/utilitySourceGroupCxx.cpp

@@ -1,5 +1,7 @@
 #include "utilitySourceGroupCxx.h"
 
+#include <clang/Tooling/JSONCompilationDatabase.h>
+
 #include "CanonicalFilePathCache.h"
 #include "CxxCompilationDatabaseSingle.h"
 #include "CxxDiagnosticConsumer.h"
@@ -48,6 +50,7 @@ namespace utility
 		const FilePath pchOutputFilePath =
 			pchDependenciesDirectoryPath.getConcatenated(pchInputFilePath.fileName()).replaceExtension(L"pch");
 
+		utility::removeIncludePchFlag(compilerFlags);
 		compilerFlags.push_back(pchInputFilePath.wstr());
 		compilerFlags.push_back(L"-emit-pch");
 		compilerFlags.push_back(L"-o");
@@ -102,6 +105,48 @@ namespace utility
 		);
 	}
 
+	bool containsIncludePchFlags(std::shared_ptr<clang::tooling::JSONCompilationDatabase> cdb)
+	{
+		for (const clang::tooling::CompileCommand& command : cdb->getAllCompileCommands())
+		{
+			if (command.CommandLine.size() != getWithRemoveIncludePchFlag(utility::convert<std::string, std::wstring>(
+				command.CommandLine,
+				[](const std::string& s) {return utility::decodeFromUtf8(s); }
+				)).size())
+			{
+				return true;
+			}
+		}
+		return false;
+	}
+
+	std::vector<std::wstring> getWithRemoveIncludePchFlag(const std::vector<std::wstring>& args)
+	{
+		std::vector<std::wstring> ret = args;
+		removeIncludePchFlag(ret);
+		return ret;
+	}
+
+	void removeIncludePchFlag(std::vector<std::wstring>& args)
+	{
+		const std::wstring includePchPrefix = L"-include-pch";
+		for (size_t i = 0; i < args.size(); i++)
+		{
+			const std::wstring arg = utility::trim(args[i]);
+			if (utility::isPrefix<std::wstring>(includePchPrefix, arg))
+			{
+				if (i + 1 < args.size() &&
+					!utility::isPrefix<std::wstring>(L"-", utility::trim(args[i + 1])) &&
+					arg == includePchPrefix)
+				{
+					args.erase(args.begin() + i + 1);
+				}
+				args.erase(args.begin() + i);
+				i--;
+			}
+		}
+	}
+
 	std::vector<std::wstring> getIncludePchFlags(const SourceGroupSettingsCxx* settings)
 	{
 		const SourceGroupSettingsWithCxxPchOptions* pchSettings =

src/lib_cxx/project/utilitySourceGroupCxx.h

@@ -5,6 +5,12 @@
 #include <string>
 #include <vector>
 
+namespace clang {
+	namespace tooling {
+		class JSONCompilationDatabase;
+	}
+}
+
 class DialogView;
 class SourceGroupSettingsCxx;
 class StorageProvider;
@@ -15,6 +21,9 @@ namespace utility
 	std::shared_ptr<Task> createBuildPchTask(
 		const SourceGroupSettingsCxx* settings, std::vector<std::wstring> compilerFlags,
 		std::shared_ptr<StorageProvider> storageProvider, std::shared_ptr<DialogView> dialogView);
+	bool containsIncludePchFlags(std::shared_ptr<clang::tooling::JSONCompilationDatabase> cdb);
+	std::vector<std::wstring> getWithRemoveIncludePchFlag(const std::vector<std::wstring>& args);
+	void removeIncludePchFlag(std::vector<std::wstring>& args);
 	std::vector<std::wstring> getIncludePchFlags(const SourceGroupSettingsCxx* settings);
 }
 

src/lib_gui/qt/project_wizard/content/path/QtProjectWizardContentPathCxxPch.cpp

@@ -1,8 +1,13 @@
 #include "QtProjectWizardContentPathCxxPch.h"
 
+#include <QMessageBox>
+
+#include "IndexerCommandCxx.h"
+#include "SourceGroupSettingsCxxCdb.h"
 #include "SourceGroupSettingsWithCxxPchOptions.h"
 #include "utility.h"
 #include "utilityFile.h"
+#include "utilitySourceGroupCxx.h"
 
 QtProjectWizardContentPathCxxPch::QtProjectWizardContentPathCxxPch(
 	std::shared_ptr<SourceGroupSettings> settings,
@@ -40,6 +45,44 @@ void QtProjectWizardContentPathCxxPch::save()
 	m_settingsCxxPch->setPchInputFilePathFilePath(FilePath(m_picker->getText().toStdWString()));
 }
 
+bool QtProjectWizardContentPathCxxPch::check()
+{
+	if (std::shared_ptr<SourceGroupSettingsCxxCdb> cdbSettings = std::dynamic_pointer_cast<SourceGroupSettingsCxxCdb>(m_settings))
+	{
+		const FilePath cdbPath = cdbSettings->getCompilationDatabasePathExpandedAndAbsolute();
+		std::shared_ptr<clang::tooling::JSONCompilationDatabase> cdb = IndexerCommandCxx::loadCDB(cdbPath);
+		if (!cdb)
+		{
+			QMessageBox msgBox;
+			msgBox.setText("Unable to open and read the provided compilation database file.");
+			msgBox.exec();
+			return false;
+		}
+
+		if (utility::containsIncludePchFlags(cdb))
+		{
+			if (m_settingsCxxPch->getPchInputFilePath().empty())
+			{
+				QMessageBox msgBox;
+				msgBox.setText("The provided compilation database file uses precompiled headers. Please specify a Precompiled Header input file.");
+				msgBox.exec();
+				return false;
+			}
+		}
+		else
+		{
+			if (!m_settingsCxxPch->getPchInputFilePath().empty())
+			{
+				QMessageBox msgBox;
+				msgBox.setText("The provided compilation database file does not use precompiled headers. Please do not specify a Precompiled Header input file.");
+				msgBox.exec();
+				return false;
+			}
+		}
+	}
+	return true;
+}
+
 std::shared_ptr<SourceGroupSettings> QtProjectWizardContentPathCxxPch::getSourceGroupSettings()
 {
 	return m_settings;

src/lib_gui/qt/project_wizard/content/path/QtProjectWizardContentPathCxxPch.h

@@ -22,6 +22,7 @@ public:
 
 	void load() override;
 	void save() override;
+	bool check() override;
 
 private:
 	std::shared_ptr<SourceGroupSettings> getSourceGroupSettings() override;

testing/project_setup/cxx_cdb/checklist.txt

@@ -13,6 +13,12 @@
 * Validate "Header Files & Directories to Index" contains "src" entry
 * Add "**/Foo.h" to "Excluded Files & Directories"
 * Click "Next"
+* Pick any file at "Precompiled Header File"
+* Click "Next"
+* Validate dialog appears that asks NOT to specify PCH input file
+* Click "OK"
+* Clear "Precompiled Header File"
+* Click "Next"
 * Click "Create"
 * Validate "All files" is the only option selectable
 * Click "Start"

testing/project_setup/cxx_cdb_pch/1_setup.sh

@@ -21,7 +21,7 @@ cp -a $SRC_PATH/. $WORKING_COPY_PATH
 echo "[" >> $CDB_PATH
 echo "  {" >> $CDB_PATH
 echo "    \"directory\": \"${WORKING_COPY_PATH}\"," >> $CDB_PATH
-echo "    \"command\": \"clang-tool -fms-extensions -fms-compatibility -fms-compatibility-version=19 -isystem \\\"${WORKING_COPY_SRC_PATH}/include\\\"  -DCDB_FLAG -D _DEBUG  -D _MT  -D _DLL  -D WIN32  -D _WINDOWS  -D BUILD_TYPE=\\\"\\\"  -D QT_WIDGETS_LIB  -D QT_GUI_LIB  -D QT_CORE_LIB  -D QT_NETWORK_LIB  -D QT_WINEXTRAS_LIB  -D QT_SVG_LIB  -D CMAKE_INTDIR=\\\"Debug\\\"  -D _MBCS -std=c++14 \\\"${WORKING_COPY_SRC_PATH}/main.cpp\\\"\"," >> $CDB_PATH
+echo "    \"command\": \"clang-tool -fms-extensions -fms-compatibility -fms-compatibility-version=19 -isystem \\\"${WORKING_COPY_SRC_PATH}/include\\\"  -DCDB_FLAG -D _DEBUG  -D _MT  -D _DLL  -D WIN32  -D _WINDOWS  -D BUILD_TYPE=\\\"\\\"  -D QT_WIDGETS_LIB  -D QT_GUI_LIB  -D QT_CORE_LIB  -D QT_NETWORK_LIB  -D QT_WINEXTRAS_LIB  -D QT_SVG_LIB  -D CMAKE_INTDIR=\\\"Debug\\\"  -D _MBCS -std=c++14 -include-pch some/file/path \\\"${WORKING_COPY_SRC_PATH}/main.cpp\\\"\"," >> $CDB_PATH
 echo "    \"file\": \"${WORKING_COPY_SRC_PATH}/main.cpp\"" >> $CDB_PATH
 echo "  }" >> $CDB_PATH
 echo "]" >> $CDB_PATH

testing/project_setup/cxx_cdb_pch/checklist.txt

@@ -14,8 +14,11 @@
 * Add "**/Foo.h" to "Excluded Files & Directories"
 * Click "Next"
 * Click "Next"
-* Add "-DCOMPILER_FLAG" to "Additional Compiler Flags"
+* Validate dialog appears that asks to specify PCH input file
+* Click "OK"
 * Add "./src/pch.h" to "Precompiled Header File"
+* Click "Next"
+* Add "-DCOMPILER_FLAG" to "Additional Compiler Flags"
 * Add "-DPCH_FLAG" to "Precompiled Header Flags"
 * Click "Create"
 * Validate "All files" is the only option selectable