commit 40e9842854430ff34b0b687cbb94e9f4a044588a
author Jonathan Roelofs <jonathan@codesourcery.com> Tue May 06 21:30:56 2014 +0000
committer Jonathan Roelofs <jonathan@codesourcery.com> Tue May 06 21:30:56 2014 +0000
tree 6f9cfaa242398ebcd758477ff08448196d64ebaf
parent 9c928478f48384ad641a3c895856fbcef0c34f22

On single threaded systems, turn mutexes into nops

http://reviews.llvm.org/D3386

llvm-svn: 208135

libcxxabi/src/cxa_guard.cpp

diff --git a/libcxxabi/src/cxa_guard.cpp b/libcxxabi/src/cxa_guard.cpp
index e403b64..b22fcbb 100644
--- a/libcxxabi/src/cxa_guard.cpp
+++ b/libcxxabi/src/cxa_guard.cpp
@@ -8,8 +8,11 @@
 //===----------------------------------------------------------------------===//
 
 #include "abort_message.h"
+#include "config.h"
 
-#include <pthread.h>
+#if !LIBCXXABI_SINGLE_THREADED
+#  include <pthread.h>
+#endif
 #include <stdint.h>
 
 /*
@@ -59,8 +62,10 @@
 
 #endif
 
+#if !LIBCXXABI_SINGLE_THREADED
 pthread_mutex_t guard_mut = PTHREAD_MUTEX_INITIALIZER;
 pthread_cond_t  guard_cv  = PTHREAD_COND_INITIALIZER;
+#endif
 
 #if defined(__APPLE__) && !defined(__arm__)
 
@@ -161,9 +166,27 @@
 extern "C"
 {
 
+#if LIBCXXABI_SINGLE_THREADED
 int __cxa_guard_acquire(guard_type* guard_object)
 {
-    char* initialized = (char*)guard_object;
+    return !is_initialized(guard_object);
+}
+
+void __cxa_guard_release(guard_type* guard_object)
+{
+    *guard_object = 0;
+    set_initialized(guard_object);
+}
+
+void __cxa_guard_abort(guard_type* guard_object)
+{
+    *guard_object = 0;
+}
+
+#else // !LIBCXXABI_SINGLE_THREADED
+
+int __cxa_guard_acquire(guard_type* guard_object)
+{
     if (pthread_mutex_lock(&guard_mut))
         abort_message("__cxa_guard_acquire failed to acquire mutex");
     int result = *initialized == 0;
@@ -226,6 +249,8 @@
         abort_message("__cxa_guard_abort failed to broadcast condition variable");
 }
 
+#endif // !LIBCXXABI_SINGLE_THREADED
+
 }  // extern "C"
 
 }  // __cxxabiv1