[llvm] r295370 - Change default TimerGroup singleton to use magic statics

[Erich Keane via llvm-commits]

Author: erichkeane
Date: Thu Feb 16 14:19:49 2017
New Revision: 295370

URL: http://llvm.org/viewvc/llvm-project?rev=295370&view=rev
Log:
Change default TimerGroup singleton to use magic statics

TimerGroup was showing up on a leak in valigrind, and 
used some pretty complex code to implement a singleton.
This patch replaces the implementation with a vastly simpler
one.

Differential Revision: https://reviews.llvm.org/D28367

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=295370&r1=295369&r2=295370&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Timer.cpp (original)
+++ llvm/trunk/lib/Support/Timer.cpp Thu Feb 16 14:19:49 2017
@@ -72,22 +72,9 @@ std::unique_ptr<raw_fd_ostream> llvm::Cr
   return llvm::make_unique<raw_fd_ostream>(2, false); // stderr.
 }
 
-
-static TimerGroup *DefaultTimerGroup = nullptr;
 static TimerGroup *getDefaultTimerGroup() {
-  TimerGroup *tmp = DefaultTimerGroup;
-  sys::MemoryFence();
-  if (tmp) return tmp;
-
-  sys::SmartScopedLock<true> Lock(*TimerLock);
-  tmp = DefaultTimerGroup;
-  if (!tmp) {
-    tmp = new TimerGroup("misc", "Miscellaneous Ungrouped Timers");
-    sys::MemoryFence();
-    DefaultTimerGroup = tmp;
-  }
-
-  return tmp;
+  static TimerGroup DefaultTimerGroup("misc", "Miscellaneous Ungrouped Timers");
+  return &DefaultTimerGroup;
 }
 
 //===----------------------------------------------------------------------===//
@@ -309,7 +296,7 @@ void TimerGroup::PrintQueuedTimers(raw_o
   // If this is not an collection of ungrouped times, print the total time.
   // Ungrouped timers don't really make sense to add up.  We still print the
   // TOTAL line to make the percentages make sense.
-  if (this != DefaultTimerGroup)
+  if (this != getDefaultTimerGroup())
     OS << format("  Total Execution Time: %5.4f seconds (%5.4f wall clock)\n",
                  Total.getProcessTime(), Total.getWallTime());
   OS << '\n';