r120013 dropped passing in the precomputed file size to 
MemoryBuffer::getFile, causing us to pick up a fstat for
every file.  Restore the optimization.

llvm-svn: 120032
diff --git a/clang/lib/Basic/FileManager.cpp b/clang/lib/Basic/FileManager.cpp
index 9572aaad..b884388 100644
--- a/clang/lib/Basic/FileManager.cpp
+++ b/clang/lib/Basic/FileManager.cpp
@@ -394,11 +394,12 @@
 getBufferForFile(const FileEntry *Entry, std::string *ErrorStr) {
   llvm::StringRef Filename = Entry->getName();
   if (FileSystemOpts.WorkingDir.empty())
-    return llvm::MemoryBuffer::getFile(Filename, ErrorStr);
+    return llvm::MemoryBuffer::getFile(Filename, ErrorStr, Entry->getSize());
   
   llvm::sys::Path FilePath(Filename);
   FixupRelativePath(FilePath, FileSystemOpts);
-  return llvm::MemoryBuffer::getFile(FilePath.c_str(), ErrorStr);
+  return llvm::MemoryBuffer::getFile(FilePath.c_str(), ErrorStr,
+                                     Entry->getSize());
 }
 
 llvm::MemoryBuffer *FileManager::
diff --git a/clang/lib/Basic/FileSystemStatCache.cpp b/clang/lib/Basic/FileSystemStatCache.cpp
index 3e13740..738af41 100644
--- a/clang/lib/Basic/FileSystemStatCache.cpp
+++ b/clang/lib/Basic/FileSystemStatCache.cpp
@@ -24,7 +24,6 @@
   if (Result == CacheMiss)
     Result = ::stat(Path, &StatBuf) ? CacheHitMissing : CacheHitExists;
   
-  
   // Do not cache failed stats, it is easy to construct common inconsistent
   // situations if we do, and they are not important for PCH performance (which
   // currently only needs the stats to construct the initial FileManager