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, 5 insertions, 3 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)