Update LLVM for rebase to r212749.

Includes a cherry-pick of:
r212948 - fixes a small issue with atomic calls

Change-Id: Ib97bd980b59f18142a69506400911a6009d9df18

1 files changed, 3 insertions, 38 deletions

diff --git a/lib/Support/Threading.cpp b/lib/Support/Threading.cpp
index 1acfa79b11..ca7f3f64aa 100644
--- a/lib/Support/Threading.cpp
+++ b/lib/Support/Threading.cpp
@@ -7,7 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This file implements llvm_start_multithreaded() and friends.
+// This file defines helper functions for running LLVM in a multi-threaded
+// environment.
 //
 //===----------------------------------------------------------------------===//
 
@@ -19,50 +20,14 @@
 
 using namespace llvm;
 
-static bool multithreaded_mode = false;
-
-static sys::Mutex* global_lock = nullptr;
-
-bool llvm::llvm_start_multithreaded() {
+bool llvm::llvm_is_multithreaded() {
 #if LLVM_ENABLE_THREADS != 0
-  assert(!multithreaded_mode && "Already multithreaded!");
-  multithreaded_mode = true;
-  global_lock = new sys::Mutex(true);
-
-  // We fence here to ensure that all initialization is complete BEFORE we
-  // return from llvm_start_multithreaded().
-  sys::MemoryFence();
   return true;
 #else
   return false;
 #endif
 }
 
-void llvm::llvm_stop_multithreaded() {
-#if LLVM_ENABLE_THREADS != 0
-  assert(multithreaded_mode && "Not currently multithreaded!");
-
-  // We fence here to insure that all threaded operations are complete BEFORE we
-  // return from llvm_stop_multithreaded().
-  sys::MemoryFence();
-
-  multithreaded_mode = false;
-  delete global_lock;
-#endif
-}
-
-bool llvm::llvm_is_multithreaded() {
-  return multithreaded_mode;
-}
-
-void llvm::llvm_acquire_global_lock() {
-  if (multithreaded_mode) global_lock->acquire();
-}
-
-void llvm::llvm_release_global_lock() {
-  if (multithreaded_mode) global_lock->release();
-}
-
 #if LLVM_ENABLE_THREADS != 0 && defined(HAVE_PTHREAD_H)
 #include <pthread.h>