4 files changed, 36 insertions, 3 deletions
diff --git a/include/clang/Basic/FileManager.h b/include/clang/Basic/FileManager.h
index ebd2812ece..d6a0cf34d9 100644
--- a/include/clang/Basic/FileManager.h
+++ b/include/clang/Basic/FileManager.h
@@ -81,7 +81,31 @@ public:
   virtual ~StatSysCallCache() {}
   virtual int stat(const char *path, struct stat *buf) = 0;
 };
- 
+
+/// \brief A stat listener that can be used by FileManager to keep
+/// track of the results of stat() calls that occur throughout the
+/// execution of the front end.
+class MemorizeStatCalls : public StatSysCallCache {
+public:
+  /// \brief The result of a stat() call. 
+  ///
+  /// The first member is the result of calling stat(). If stat()
+  /// found something, the second member is a copy of the stat
+  /// structure.
+  typedef std::pair<int, struct stat> StatResult;
+
+  /// \brief The set of stat() calls that have been 
+  llvm::StringMap<StatResult, llvm::BumpPtrAllocator> StatCalls;
+
+  typedef llvm::StringMap<StatResult, llvm::BumpPtrAllocator>::const_iterator
+    iterator;
+  
+  iterator begin() const { return StatCalls.begin(); }
+  iterator end() const { return StatCalls.end(); }
+
+  virtual int stat(const char *path, struct stat *buf);
+};
+
 /// FileManager - Implements support for file system lookup, file system
 /// caching, and directory search management.  This also handles more advanced
 /// properties, such as uniquing files based on "inode", so that a file with two
diff --git a/include/clang/Frontend/PCHBitCodes.h b/include/clang/Frontend/PCHBitCodes.h
index 436a265a41..f2aed97893 100644
--- a/include/clang/Frontend/PCHBitCodes.h
+++ b/include/clang/Frontend/PCHBitCodes.h
@@ -185,7 +185,10 @@ namespace clang {
       /// This set contains the source location entry for the
       /// predefines buffer and for any file entries that need to be
       /// preloaded.
-      SOURCE_LOCATION_PRELOADS = 16
+      SOURCE_LOCATION_PRELOADS = 16,
+
+      /// \brief Record code for the stat() cache.
+      STAT_CACHE = 17
     };
 
     /// \brief Record types used within a source manager block.
diff --git a/include/clang/Frontend/PCHReader.h b/include/clang/Frontend/PCHReader.h
index 07f2bb260f..a955b80695 100644
--- a/include/clang/Frontend/PCHReader.h
+++ b/include/clang/Frontend/PCHReader.h
@@ -226,6 +226,10 @@ private:
   /// been de-serialized.
   std::multimap<unsigned, AddrLabelExpr *> UnresolvedAddrLabelExprs;
 
+  /// \brief The number of stat() calls that hit/missed the stat
+  /// cache.
+  unsigned NumStatHits, NumStatMisses;
+
   /// \brief The number of source location entries de-serialized from
   /// the PCH file.
   unsigned NumSLocEntriesRead;
diff --git a/include/clang/Frontend/PCHWriter.h b/include/clang/Frontend/PCHWriter.h
index 96c6c79de4..b16058c154 100644
--- a/include/clang/Frontend/PCHWriter.h
+++ b/include/clang/Frontend/PCHWriter.h
@@ -33,6 +33,7 @@ namespace clang {
 
 class ASTContext;
 class LabelStmt;
+class MemorizeStatCalls;
 class Preprocessor;
 class Sema;
 class SourceManager;
@@ -161,6 +162,7 @@ private:
   void WriteBlockInfoBlock();
   void WriteTargetTriple(const TargetInfo &Target);
   void WriteLanguageOptions(const LangOptions &LangOpts);
+  void WriteStatCache(MemorizeStatCalls &StatCalls);
   void WriteSourceManagerBlock(SourceManager &SourceMgr, 
                                const Preprocessor &PP);
   void WritePreprocessor(const Preprocessor &PP);
@@ -183,7 +185,7 @@ public:
   PCHWriter(llvm::BitstreamWriter &Stream);
   
   /// \brief Write a precompiled header for the given semantic analysis.
-  void WritePCH(Sema &SemaRef);
+  void WritePCH(Sema &SemaRef, MemorizeStatCalls *StatCalls);
 
   /// \brief Emit a source location.
   void AddSourceLocation(SourceLocation Loc, RecordData &Record);