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, 3 insertions, 0 deletions

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;
 };