From c4c31e2020a7ad36f055a668eca10902e1d724e9 Mon Sep 17 00:00:00 2001
From: Erich Keane <erich.keane@intel.com>
Date: Thu, 16 Feb 2017 20:19:49 +0000
Subject: [PATCH] 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

llvm-svn: 295370
---
 llvm/lib/Support/Timer.cpp | 19 +++----------------
 1 file changed, 3 insertions(+), 16 deletions(-)

diff --git a/llvm/lib/Support/Timer.cpp b/llvm/lib/Support/Timer.cpp
index fbd73d0b6b3b..8d68c6ae9682 100644
--- a/llvm/lib/Support/Timer.cpp
+++ b/llvm/lib/Support/Timer.cpp
@@ -72,22 +72,9 @@ std::unique_ptr<raw_fd_ostream> llvm::CreateInfoOutputFile() {
   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_ostream &OS) {
   // 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';