From cb680661eb84cb0b034a55678a3445aede52bf8c Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Wed, 6 Feb 2013 18:08:37 +0000
Subject: [PATCH] Eliminate a race condition with the global module index.

Essentially, a module file on disk could change size between the time
we stat() it and the time we open it, and we need to be robust against
such a problem.

llvm-svn: 174529
---
 clang/lib/Serialization/GlobalModuleIndex.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Serialization/GlobalModuleIndex.cpp b/clang/lib/Serialization/GlobalModuleIndex.cpp
index 72165bc..5b2ab91 100644
--- a/clang/lib/Serialization/GlobalModuleIndex.cpp
+++ b/clang/lib/Serialization/GlobalModuleIndex.cpp
@@ -536,7 +536,8 @@ namespace {
 bool GlobalModuleIndexBuilder::loadModuleFile(const FileEntry *File) {
   // Open the module file.
   OwningPtr<llvm::MemoryBuffer> Buffer;
-  Buffer.reset(FileMgr.getBufferForFile(File));
+  std::string ErrorStr;
+  Buffer.reset(FileMgr.getBufferForFile(File, &ErrorStr, /*isVolatile=*/true));
   if (!Buffer) {
     return true;
   }
-- 
2.7.4