r210604 - Revert "Clang changes to support LLVM removal of runtime multithreading"

[Zachary Turner]

Author: zturner
Date: Tue Jun 10 18:17:11 2014
New Revision: 210604

URL: http://llvm.org/viewvc/llvm-project?rev=210604&view=rev
Log:
Revert "Clang changes to support LLVM removal of runtime multithreading"

This reverts r210601.

Modified:
    cfe/trunk/tools/libclang/CIndex.cpp

Modified: cfe/trunk/tools/libclang/CIndex.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/tools/libclang/CIndex.cpp?rev=210604&r1=210603&r2=210604&view=diff
==============================================================================
--- cfe/trunk/tools/libclang/CIndex.cpp (original)
+++ cfe/trunk/tools/libclang/CIndex.cpp Tue Jun 10 18:17:11 2014
@@ -2556,8 +2556,8 @@ buildPieces(unsigned NameFlags, bool IsM
 // Misc. API hooks.
 //===----------------------------------------------------------------------===//               
 
-static llvm::sys::Mutex LoggingMutex;
-static std::once_flag InstalledErrorHandlerFlag;
+static llvm::sys::Mutex EnableMultithreadingMutex;
+static bool EnabledMultithreading;
 
 static void fatal_error_handler(void *user_data, const std::string& reason,
                                 bool gen_crash_diag) {
@@ -2575,8 +2575,15 @@ CXIndex clang_createIndex(int excludeDec
   if (!getenv("LIBCLANG_DISABLE_CRASH_RECOVERY"))
     llvm::CrashRecoveryContext::Enable();
 
-  std::call_once(InstalledErrorHandlerFlag,
-      []() {llvm::install_fatal_error_handler(fatal_error_handler, nullptr);});
+  // Enable support for multithreading in LLVM.
+  {
+    llvm::sys::ScopedLock L(EnableMultithreadingMutex);
+    if (!EnabledMultithreading) {
+      llvm::install_fatal_error_handler(fatal_error_handler, nullptr);
+      llvm::llvm_start_multithreaded();
+      EnabledMultithreading = true;
+    }
+  }
 
   CIndexer *CIdxr = new CIndexer();
   if (excludeDeclarationsFromPCH)
@@ -6952,7 +6959,7 @@ Logger &cxindex::Logger::operator<<(cons
 cxindex::Logger::~Logger() {
   LogOS.flush();
 
-  llvm::sys::ScopedLock L(LoggingMutex);
+  llvm::sys::ScopedLock L(EnableMultithreadingMutex);
 
   static llvm::TimeRecord sBeginTR = llvm::TimeRecord::getCurrentTime();