Clang: Save compilation database to the build directory

For example CMake puts compile_commands.json into the build
directory and it makes sense because it uses some target-specific
command line options.

Change-Id: I92a5b391f35e3f75bbcf41b8efff448f197895bb
Reviewed-by: Marco Bubke <marco.bubke@qt.io>
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

3 files changed, 14 insertions, 11 deletions

diff --git a/src/plugins/clangcodemodel/clangcodemodelplugin.cpp b/src/plugins/clangcodemodel/clangcodemodelplugin.cpp
index 11de94c395..a4a1591cf4 100644
--- a/src/plugins/clangcodemodel/clangcodemodelplugin.cpp
+++ b/src/plugins/clangcodemodel/clangcodemodelplugin.cpp
@@ -68,13 +68,12 @@ void ClangCodeModelPlugin::generateCompilationDB() {
     using namespace CppTools;
 
     ProjectExplorer::Project *project = ProjectExplorer::SessionManager::startupProject();
-    if (!project)
+    if (!project || !project->activeTarget())
         return;
 
-    m_generatorWatcher.setFuture(QtConcurrent::run(
-                                     &Utils::generateCompilationDB,
-                                     project->projectDirectory(),
-                                     CppModelManager::instance()->projectInfo(project)));
+    m_generatorWatcher.setFuture(
+        QtConcurrent::run(&Utils::generateCompilationDB,
+                          CppModelManager::instance()->projectInfo(project)));
 }
 
 static bool isDBGenerationEnabled(ProjectExplorer::Project *project)
diff --git a/src/plugins/clangcodemodel/clangutils.cpp b/src/plugins/clangcodemodel/clangutils.cpp
index c8e74f663f..599b561011 100644
--- a/src/plugins/clangcodemodel/clangutils.cpp
+++ b/src/plugins/clangcodemodel/clangutils.cpp
@@ -313,9 +313,9 @@ static ::Utils::FileName compilerPath(const CppTools::ProjectPart &projectPart)
     return toolchain->compilerCommand();
 }
 
-static ::Utils::FileName buildDirectory(const CppTools::ProjectPart &projectPart)
+static ::Utils::FileName buildDirectory(const ProjectExplorer::Project &project)
 {
-    ProjectExplorer::Target *target = projectPart.project->activeTarget();
+    ProjectExplorer::Target *target = project.activeTarget();
     if (!target)
         return ::Utils::FileName();
 
@@ -386,17 +386,21 @@ static QJsonObject createFileObject(const ::Utils::FileName &buildDir,
     return fileObject;
 }
 
-void generateCompilationDB(::Utils::FileName projectDir, CppTools::ProjectInfo projectInfo)
+void generateCompilationDB(CppTools::ProjectInfo projectInfo)
 {
-    QFile compileCommandsFile(projectDir.toString() + "/compile_commands.json");
+    const ::Utils::FileName buildDir = buildDirectory(*projectInfo.project());
+    QTC_ASSERT(!buildDir.isEmpty(), return;);
 
+    QDir dir(buildDir.toString());
+    if (!dir.exists())
+        dir.mkpath(dir.path());
+    QFile compileCommandsFile(buildDir.toString() + "/compile_commands.json");
     const bool fileOpened = compileCommandsFile.open(QIODevice::WriteOnly | QIODevice::Truncate);
     if (!fileOpened)
         return;
     compileCommandsFile.write("[");
 
     for (ProjectPart::Ptr projectPart : projectInfo.projectParts()) {
-        const ::Utils::FileName buildDir = buildDirectory(*projectPart);
         const QStringList args = projectPartArguments(*projectPart);
         for (const ProjectFile &projFile : projectPart->files) {
             const QJsonObject json = createFileObject(buildDir, args, *projectPart, projFile);
diff --git a/src/plugins/clangcodemodel/clangutils.h b/src/plugins/clangcodemodel/clangutils.h
index 4db869896b..8ced14f5ad 100644
--- a/src/plugins/clangcodemodel/clangutils.h
+++ b/src/plugins/clangcodemodel/clangutils.h
@@ -70,7 +70,7 @@ QString diagnosticCategoryPrefixRemoved(const QString &text);
 
 ::Utils::CodeModelIcon::Type iconTypeForToken(const ClangBackEnd::TokenInfoContainer &token);
 
-void generateCompilationDB(::Utils::FileName projectDir, CppTools::ProjectInfo projectInfo);
+void generateCompilationDB(CppTools::ProjectInfo projectInfo);
 
 class DiagnosticTextInfo
 {