ClangTools: use VFSoverlay if the clang tool supports it

check the help output of a clang tool whether virtual file
system overlay is supported. Prepares for the vfso support
of clazy-standalone.

Change-Id: I157c94de1dda41c83945c9bc8a4c2e132b2e6551
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/clangtools/clangtidyclazyrunner.cpp

@@ -72,21 +72,6 @@ static QStringList clazyChecksArguments(const ClangDiagnosticConfig diagnosticCo
     return {};
 }
 
-static QStringList mainToolArguments(const QString &mainFilePath, const QString &outputFilePath)
-{
-    return {
-        "-export-fixes=" + outputFilePath,
-        QDir::toNativeSeparators(mainFilePath),
-    };
-}
-
-static QString virtualFileSystemOverlay(const QString &overlayFilePath)
-{
-    if (overlayFilePath.isEmpty())
-        return {};
-    return "--vfsoverlay=" + overlayFilePath;
-}
-
 static QStringList clangArguments(const ClangDiagnosticConfig &diagnosticConfig,
                                   const QStringList &baseOptions)
 {
@@ -110,8 +95,7 @@ ClangTidyRunner::ClangTidyRunner(const ClangDiagnosticConfig &config, QObject *p
     setExecutable(clangTidyExecutable());
     setArgsCreator([this, config](const QStringList &baseOptions) {
         return QStringList() << tidyChecksArguments(config)
-                             << mainToolArguments(fileToAnalyze(), outputFilePath())
-                             << virtualFileSystemOverlay(m_overlayFilePath)
+                             << mainToolArguments()
                              << "--"
                              << clangArguments(config, baseOptions);
     });
@@ -124,11 +108,10 @@ ClazyStandaloneRunner::ClazyStandaloneRunner(const ClangDiagnosticConfig &config
     setOutputFileFormat(OutputFileFormat::Yaml);
     setExecutable(clazyStandaloneExecutable());
     setArgsCreator([this, config](const QStringList &baseOptions) {
-        return QStringList()
-            << clazyChecksArguments(config)
-            << mainToolArguments(fileToAnalyze(), outputFilePath())
-            << "--"
-            << clangArguments(config, baseOptions);
+        return QStringList() << clazyChecksArguments(config)
+                             << mainToolArguments()
+                             << "--"
+                             << clangArguments(config, baseOptions);
     });
 }
 

src/plugins/clangtools/clangtoolrunner.cpp

@@ -73,6 +73,29 @@ void ClangToolRunner::init(const QString &outputDirPath,
     connect(&m_process, &QProcess::readyRead, this, &ClangToolRunner::onProcessOutput);
 }
 
+QStringList ClangToolRunner::mainToolArguments() const
+{
+    QStringList result;
+    result << "-export-fixes=" + m_outputFilePath;
+    if (!m_overlayFilePath.isEmpty() && supportsVFSOverlay())
+        result << "--vfsoverlay=" + m_overlayFilePath;
+    result << QDir::toNativeSeparators(m_fileToAnalyze);
+    return result;
+}
+
+bool ClangToolRunner::supportsVFSOverlay() const
+{
+    static QMap<QString, bool> vfsCapabilities;
+    auto it = vfsCapabilities.find(m_executable);
+    if (it == vfsCapabilities.end()) {
+        Utils::SynchronousProcess p;
+        Utils::SynchronousProcessResponse response = p.runBlocking(
+            Utils::CommandLine(m_executable, {"--help"}));
+        it = vfsCapabilities.insert(m_executable, response.allOutput().contains("vfsoverlay"));
+    }
+    return it.value();
+}
+
 ClangToolRunner::~ClangToolRunner()
 {
     if (m_process.state() != QProcess::NotRunning) {

src/plugins/clangtools/clangtoolrunner.h

@@ -59,6 +59,8 @@ public:
     OutputFileFormat outputFileFormat() const { return m_outputFileFormat; }
     QString fileToAnalyze() const { return m_fileToAnalyze; }
     QString outputFilePath() const { return m_outputFilePath; }
+    QStringList mainToolArguments() const;
+    bool supportsVFSOverlay() const;
 
     // compilerOptions is expected to contain everything except:
     //   (1) file to analyze

src/plugins/clangtools/documentclangtoolrunner.cpp

@@ -186,7 +186,7 @@ void DocumentClangToolRunner::run()
                             return createRunner<ClangTidyRunner>(config, env);
                         };
                     }
-                    if (config.isClazyEnabled() && !m_document->isModified()) {
+                    if (config.isClazyEnabled()) {
                         m_runnerCreators << [this, env, config]() {
                             return createRunner<ClazyStandaloneRunner>(config, env);
                         };
@@ -218,7 +218,8 @@ void DocumentClangToolRunner::runNext()
         auto [clangIncludeDir, clangVersion] = getClangIncludeDirAndVersion(m_currentRunner.get());
         qCDebug(LOG) << Q_FUNC_INFO << m_currentRunner->executable() << clangIncludeDir
                      << clangVersion << m_fileInfo.file;
-        if (clangIncludeDir.isEmpty() || clangVersion.isEmpty()) {
+        if (clangIncludeDir.isEmpty() || clangVersion.isEmpty()
+            || (m_document->isModified() && !m_currentRunner->supportsVFSOverlay())) {
             runNext();
         } else {
             AnalyzeUnit unit(m_fileInfo, clangIncludeDir, clangVersion);