[llvm-commits] [llvm] r73963 - /llvm/trunk/lib/Support/Timer.cpp

[Owen Anderson]

Author: resistor
Date: Tue Jun 23 12:33:37 2009
New Revision: 73963

URL: http://llvm.org/viewvc/llvm-project?rev=73963&view=rev
Log:
Make the lazy initialization of DefaultTimerGroup threadsafe.

Modified:
    llvm/trunk/lib/Support/Timer.cpp

Modified: llvm/trunk/lib/Support/Timer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Timer.cpp?rev=73963&r1=73962&r2=73963&view=diff

==============================================================================
--- llvm/trunk/lib/Support/Timer.cpp (original)
+++ llvm/trunk/lib/Support/Timer.cpp Tue Jun 23 12:33:37 2009
@@ -52,8 +52,20 @@
 
 static TimerGroup *DefaultTimerGroup = 0;
 static TimerGroup *getDefaultTimerGroup() {
-  if (DefaultTimerGroup) return DefaultTimerGroup;
-  return DefaultTimerGroup = new TimerGroup("Miscellaneous Ungrouped Timers");
+  TimerGroup* tmp = DefaultTimerGroup;
+  sys::MemoryFence();
+  if (!tmp) {
+    llvm_acquire_global_lock();
+    tmp = DefaultTimerGroup;
+    if (!tmp) {
+      tmp = new TimerGroup("Miscellaneous Ungrouped Timers");
+      sys::MemoryFence();
+      DefaultTimerGroup = tmp;
+    }
+    llvm_release_global_lock();
+  }
+  
+  return tmp;
 }
 
 Timer::Timer(const std::string &N)
@@ -377,11 +389,5 @@
     if (OutStream != cerr.stream() && OutStream != cout.stream())
       delete OutStream;   // Close the file...
   }
-
-  // Delete default timer group!
-  if (NumTimers == 0 && this == DefaultTimerGroup) {
-    delete DefaultTimerGroup;
-    DefaultTimerGroup = 0;
-  }
 }