PTH: Cache stat information for files in the PTH file. Hook up FileManager

 to use this stat information in the PTH file using a 'StatSysCallCache' object.

Performance impact (Cocoa.h, PTH):
- number of stat calls reduces from 1230 to 425
- fsyntax-only: time improves by 4.2% 

We can reduce the number of stat calls to almost zero by caching negative stat
calls and directory stat calls in the PTH file as well.

llvm-svn: 64353

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/lib/Lex/Preprocessor.cpp b/clang/lib/Lex/Preprocessor.cpp
index db5ca2bd7fe..69aa7cb51a6 100644
--- a/clang/lib/Lex/Preprocessor.cpp
+++ b/clang/lib/Lex/Preprocessor.cpp
@@ -32,6 +32,7 @@
 #include "clang/Lex/ScratchBuffer.h"
 #include "clang/Lex/LexDiagnostic.h"
 #include "clang/Basic/SourceManager.h"
+#include "clang/Basic/FileManager.h"
 #include "clang/Basic/TargetInfo.h"
 #include "llvm/ADT/APFloat.h"
 #include "llvm/ADT/SmallVector.h"
@@ -117,6 +118,11 @@ Preprocessor::~Preprocessor() {
   delete Callbacks;
 }
 
+void Preprocessor::setPTHManager(PTHManager* pm) {
+  PTH.reset(pm);
+  FileMgr.setStatCache(PTH->createStatCache());
+}
+
 void Preprocessor::DumpToken(const Token &Tok, bool DumpFlags) const {
   llvm::cerr << tok::getTokenName(Tok.getKind()) << " '"
              << getSpelling(Tok) << "'";