Merge the C/C++ include scanners

We had one scanner for every type of file in the C family, all of which
collected the same set of includes, but under a different entry in the
scanner cache. Thus, lots of header files were unnecessarily re-scanned.
We fix this by making the scanner plugins declare a *list* of tags they
can handle and passing the currently active tags in the open() function.

========== Performance data for Rule Execution ==========
    Old instruction count: 3775190973
    New instruction count: 3441085735
    Relative change: -9 %
    Old peak memory usage: 18174216 Bytes
    New peak memory usage: 17307600 Bytes
    Relative change: -5 %

Change-Id: I222d1ec4bbfbc06ecd8c81faa55a500bc0da1ee6
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

6 files changed, 35 insertions, 19 deletions

diff --git a/src/lib/corelib/buildgraph/depscanner.cpp b/src/lib/corelib/buildgraph/depscanner.cpp
index d88759f3b..824c3cf75 100644
--- a/src/lib/corelib/buildgraph/depscanner.cpp
+++ b/src/lib/corelib/buildgraph/depscanner.cpp
@@ -88,12 +88,13 @@ QStringList PluginDependencyScanner::collectSearchPaths(Artifact *artifact)
     }
 }
 
-QStringList PluginDependencyScanner::collectDependencies(FileResourceBase *file)
+QStringList PluginDependencyScanner::collectDependencies(FileResourceBase *file,
+                                                         const char *fileTags)
 {
     QSet<QString> result;
     QString baseDirOfInFilePath = file->dirPath();
     const QString &filepath = file->filePath();
-    void *scannerHandle = m_plugin->open(filepath.utf16(), ScanForDependenciesFlag);
+    void *scannerHandle = m_plugin->open(filepath.utf16(), fileTags, ScanForDependenciesFlag);
     if (!scannerHandle)
         return QStringList();
     forever {
@@ -150,8 +151,9 @@ QStringList UserDependencyScanner::collectSearchPaths(Artifact *artifact)
     return evaluate(artifact, m_scanner->searchPathsScript);
 }
 
-QStringList UserDependencyScanner::collectDependencies(FileResourceBase *file)
+QStringList UserDependencyScanner::collectDependencies(FileResourceBase *file, const char *fileTags)
 {
+    Q_UNUSED(fileTags);
     // ### support user dependency scanners for file deps
     Artifact *artifact = dynamic_cast<Artifact *>(file);
     if (!artifact)
diff --git a/src/lib/corelib/buildgraph/depscanner.h b/src/lib/corelib/buildgraph/depscanner.h
index 342d88b3c..e0fe52028 100644
--- a/src/lib/corelib/buildgraph/depscanner.h
+++ b/src/lib/corelib/buildgraph/depscanner.h
@@ -63,7 +63,7 @@ public:
     virtual ~DependencyScanner() {}
 
     virtual QStringList collectSearchPaths(Artifact *artifact) = 0;
-    virtual QStringList collectDependencies(FileResourceBase *file) = 0;
+    virtual QStringList collectDependencies(FileResourceBase *file, const char *fileTags) = 0;
     virtual bool recursive() const = 0;
     virtual const void *key() const = 0;
 };
@@ -75,7 +75,7 @@ public:
 
 private:
     QStringList collectSearchPaths(Artifact *artifact);
-    QStringList collectDependencies(FileResourceBase *file);
+    QStringList collectDependencies(FileResourceBase *file, const char *fileTags);
     bool recursive() const;
     const void *key() const;
 
@@ -90,7 +90,7 @@ public:
 
 private:
     QStringList collectSearchPaths(Artifact *artifact);
-    QStringList collectDependencies(FileResourceBase *file);
+    QStringList collectDependencies(FileResourceBase *file, const char *fileTags);
     bool recursive() const;
     const void *key() const;
 
diff --git a/src/lib/corelib/buildgraph/inputartifactscanner.cpp b/src/lib/corelib/buildgraph/inputartifactscanner.cpp
index 560ac0a9f..882b9627c 100644
--- a/src/lib/corelib/buildgraph/inputartifactscanner.cpp
+++ b/src/lib/corelib/buildgraph/inputartifactscanner.cpp
@@ -115,16 +115,6 @@ static void resolveDepencency(const ScanResultCache::Dependency &dependency,
         result->filePath = absFilePath;
 }
 
-static void scanWithScannerPlugin(DependencyScanner *scanner,
-                                  FileResourceBase *fileToBeScanned,
-                                  ScanResultCache::Result *scanResult)
-{
-    QStringList dependencies = scanner->collectDependencies(fileToBeScanned);
-    foreach (const QString &s, dependencies)
-        scanResult->deps += ScanResultCache::Dependency(s);
-    scanResult->valid = true;
-}
-
 InputArtifactScanner::InputArtifactScanner(Artifact *artifact, InputArtifactScannerContext *ctx,
                                            const Logger &logger)
     : m_artifact(artifact), m_context(ctx), m_newDependencyAdded(false), m_logger(logger)
@@ -176,6 +166,10 @@ void InputArtifactScanner::scanForFileDependencies(Artifact *inputArtifact)
     QList<FileResourceBase *> filesToScan;
     filesToScan.append(inputArtifact);
     const QSet<DependencyScanner *> scanners = scannersForArtifact(inputArtifact);
+    if (scanners.isEmpty())
+        return;
+    m_fileTagsForScanner = inputArtifact->fileTags().toStringList().join(QLatin1Char(','))
+            .toLatin1().constData();
     while (!filesToScan.isEmpty()) {
         FileResourceBase *fileToBeScanned = filesToScan.takeFirst();
         const QString &filePathToBeScanned = fileToBeScanned->filePath();
@@ -364,6 +358,17 @@ void InputArtifactScanner::handleDependency(ResolvedDependency &dependency)
     }
 }
 
+void InputArtifactScanner::scanWithScannerPlugin(DependencyScanner *scanner,
+                                                 FileResourceBase *fileToBeScanned,
+                                                 ScanResultCache::Result *scanResult)
+{
+    const QStringList &dependencies
+            = scanner->collectDependencies(fileToBeScanned, m_fileTagsForScanner);
+    for (const QString &s : dependencies)
+        scanResult->deps += ScanResultCache::Dependency(s);
+    scanResult->valid = true;
+}
+
 InputArtifactScannerContext::DependencyScannerCacheItem::DependencyScannerCacheItem() : valid(false)
 {
 }
diff --git a/src/lib/corelib/buildgraph/inputartifactscanner.h b/src/lib/corelib/buildgraph/inputartifactscanner.h
index 62f976d5d..39304879c 100644
--- a/src/lib/corelib/buildgraph/inputartifactscanner.h
+++ b/src/lib/corelib/buildgraph/inputartifactscanner.h
@@ -140,9 +140,12 @@ private:
             const ScanResultCache::Result &scanResult, QList<FileResourceBase *> *artifactsToScan,
             InputArtifactScannerContext::ScannerResolvedDependenciesCache &cache);
     void handleDependency(ResolvedDependency &dependency);
+    void scanWithScannerPlugin(DependencyScanner *scanner, FileResourceBase *fileToBeScanned,
+                               ScanResultCache::Result *scanResult);
 
     Artifact * const m_artifact;
     InputArtifactScannerContext *const m_context;
+    const char *m_fileTagsForScanner;
     bool m_newDependencyAdded;
     Logger m_logger;
 };
diff --git a/src/lib/corelib/buildgraph/qtmocscanner.cpp b/src/lib/corelib/buildgraph/qtmocscanner.cpp
index be133630b..fc0e54d77 100644
--- a/src/lib/corelib/buildgraph/qtmocscanner.cpp
+++ b/src/lib/corelib/buildgraph/qtmocscanner.cpp
@@ -92,7 +92,9 @@ static ScanResultCache::Result runScanner(ScannerPlugin *scanner, const Artifact
     ScanResultCache::Result scanResult = scanResultCache->value(scanner, filepath);
     if (!scanResult.valid) {
         scanResult.valid = true;
-        void *opaq = scanner->open(filepath.utf16(),
+        const char * const tagsForScanner
+                = artifact->fileTags().toStringList().join(QLatin1Char(',')).toLatin1().constData();
+        void *opaq = scanner->open(filepath.utf16(), tagsForScanner,
                                    ScanForDependenciesFlag | ScanForFileTagsFlag);
         if (!opaq || !scanner->additionalFileTags)
             return scanResult;
diff --git a/src/lib/corelib/tools/scannerpluginmanager.cpp b/src/lib/corelib/tools/scannerpluginmanager.cpp
index 12e38c1de..883eb7c56 100644
--- a/src/lib/corelib/tools/scannerpluginmanager.cpp
+++ b/src/lib/corelib/tools/scannerpluginmanager.cpp
@@ -75,8 +75,12 @@ QList<ScannerPlugin *> ScannerPluginManager::scannersForFileTag(const FileTag &f
 
 void ScannerPluginManager::loadPlugins(ScannerPlugin **plugins)
 {
-    for (int i = 0; plugins[i] != 0; ++i)
-        m_scannerPlugins[FileTag(plugins[i]->fileTag)] += plugins[i];
+    for (int i = 0; plugins[i] != 0; ++i) {
+        const FileTags &fileTags = FileTags::fromStringList(
+                    QString::fromLatin1(plugins[i]->fileTags).split(QLatin1Char(',')));
+        for (const FileTag &tag : fileTags)
+        m_scannerPlugins[tag] += plugins[i];
+    }
 }
 
 void ScannerPluginManager::loadPlugins(const QStringList &pluginPaths, const Logger &logger)