3 files changed, 28 insertions, 34 deletions
diff --git a/llvm/include/llvm-c/Core.h b/llvm/include/llvm-c/Core.h
index 0e78ed71fa9..8693a3020ab 100644
--- a/llvm/include/llvm-c/Core.h
+++ b/llvm/include/llvm-c/Core.h
@@ -2848,16 +2848,13 @@ void LLVMDisposePassManager(LLVMPassManagerRef PM);
  * @{
  */
 
-/** Allocate and initialize structures needed to make LLVM safe for
-    multithreading. The return value indicates whether multithreaded
-    initialization succeeded. Must be executed in isolation from all
-    other LLVM api calls.
-    @see llvm::llvm_start_multithreaded */
+/** Deprecated: Multi-threading can only be enabled/disabled with the compile
+    time define LLVM_ENABLE_THREADS.  This function always returns
+    LLVMIsMultithreaded(). */
 LLVMBool LLVMStartMultithreaded(void);
 
-/** Deallocate structures necessary to make LLVM safe for multithreading.
-    Must be executed in isolation from all other LLVM api calls.
-    @see llvm::llvm_stop_multithreaded */
+/** Deprecated: Multi-threading can only be enabled/disabled with the compile
+    time define LLVM_ENABLE_THREADS. */
 void LLVMStopMultithreaded(void);
 
 /** Check whether LLVM is executing in thread-safe mode or not.
diff --git a/llvm/include/llvm/Support/ManagedStatic.h b/llvm/include/llvm/Support/ManagedStatic.h
index 1bb8cea092f..d8fbfeb8e20 100644
--- a/llvm/include/llvm/Support/ManagedStatic.h
+++ b/llvm/include/llvm/Support/ManagedStatic.h
@@ -103,9 +103,6 @@ void llvm_shutdown();
 /// llvm_shutdown() when it is destroyed.
 struct llvm_shutdown_obj {
   llvm_shutdown_obj() { }
-  explicit llvm_shutdown_obj(bool multithreaded) {
-    if (multithreaded) llvm_start_multithreaded();
-  }
   ~llvm_shutdown_obj() { llvm_shutdown(); }
 };
 
diff --git a/llvm/include/llvm/Support/Threading.h b/llvm/include/llvm/Support/Threading.h
index a7e8774558d..75b6ddbfda2 100644
--- a/llvm/include/llvm/Support/Threading.h
+++ b/llvm/include/llvm/Support/Threading.h
@@ -14,32 +14,32 @@
 #ifndef LLVM_SUPPORT_THREADING_H
 #define LLVM_SUPPORT_THREADING_H
 
+#include "llvm/Config/llvm-config.h"
+#include "llvm/Support/Compiler.h"
+#include <mutex>
+
 namespace llvm {
-  /// llvm_start_multithreaded - Allocate and initialize structures needed to
-  /// make LLVM safe for multithreading.  The return value indicates whether
-  /// multithreaded initialization succeeded.  LLVM will still be operational
-  /// on "failed" return, and will still be safe for hosting threading
-  /// applications in the JIT, but will not be safe for concurrent calls to the
-  /// LLVM APIs.
-  /// THIS MUST EXECUTE IN ISOLATION FROM ALL OTHER LLVM API CALLS.
-  bool llvm_start_multithreaded();
-
-  /// llvm_stop_multithreaded - Deallocate structures necessary to make LLVM
-  /// safe for multithreading.
-  /// THIS MUST EXECUTE IN ISOLATION FROM ALL OTHER LLVM API CALLS.
-  void llvm_stop_multithreaded();
-
-  /// llvm_is_multithreaded - Check whether LLVM is executing in thread-safe
-  /// mode or not.
-  bool llvm_is_multithreaded();
 
-  /// acquire_global_lock - Acquire the global lock.  This is a no-op if called
-  /// before llvm_start_multithreaded().
-  void llvm_acquire_global_lock();
+#if LLVM_ENABLE_THREADS != 0
+  typedef std::mutex mutex;
+  typedef std::recursive_mutex recursive_mutex;
+#else
+  class null_mutex {
+  public:
+    void lock() { }
+    void unlock() { }
+    bool try_lock() { return true; }
+  };
+  typedef null_mutex mutex;
+  typedef null_mutex recursive_mutex;
+#endif
 
-  /// release_global_lock - Release the global lock.  This is a no-op if called
-  /// before llvm_start_multithreaded().
-  void llvm_release_global_lock();
+  /// llvm_get_global_lock() - returns the llvm global lock object.
+  llvm::recursive_mutex &llvm_get_global_lock();
+
+  /// llvm_is_multithreaded() - returns true if LLVM is compiled with support
+  /// for multiple threads, and false otherwise.
+  bool llvm_is_multithreaded();
 
   /// llvm_execute_on_thread - Execute the given \p UserFn on a separate
   /// thread, passing it the provided \p UserData.