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>

1 files changed, 15 insertions, 10 deletions

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)
 {
 }