[PATCH] D131059: [Timer][Statistics] Make global constructor ordering more robust

[Nicolai Hähnle via Phabricator via llvm-commits]

nhaehnle created this revision.
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It was observed in D129117 <https://reviews.llvm.org/D129117> that the subtle dependency between statistic
and timer code is not entirely robust: the global destructor
~StatisticInfo indirectly calls CreateInfoOutputFile, which requires
the LibSupportInfoOutputFilename to not have been destructed.

By constructing LibSupportInfoOutputFilename before the StatisticInfo
object, the order of destruction is guaranteed.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D131059

Files:
  llvm/include/llvm/Support/Timer.h
  llvm/lib/Support/Statistic.cpp
  llvm/lib/Support/Timer.cpp


Index: llvm/lib/Support/Timer.cpp
===================================================================
--- llvm/lib/Support/Timer.cpp
+++ llvm/lib/Support/Timer.cpp
@@ -499,7 +499,8 @@
   return delim;
 }
 
-void TimerGroup::ConstructTimerLists() {
+void TimerGroup::ConstructForStatistics() {
+  (void)getLibSupportInfoOutputFilename();
   (void)*NamedGroupedTimers;
 }
 
Index: llvm/lib/Support/Statistic.cpp
===================================================================
--- llvm/lib/Support/Statistic.cpp
+++ llvm/lib/Support/Statistic.cpp
@@ -120,8 +120,9 @@
 }
 
 StatisticInfo::StatisticInfo() {
-  // Ensure timergroup lists are created first so they are destructed after us.
-  TimerGroup::ConstructTimerLists();
+  // Ensure that necessary timer global objects are created first so they are
+  // destructed after us.
+  TimerGroup::ConstructForStatistics();
 }
 
 // Print information when destroyed, iff command line option is specified.
Index: llvm/include/llvm/Support/Timer.h
===================================================================
--- llvm/include/llvm/Support/Timer.h
+++ llvm/include/llvm/Support/Timer.h
@@ -231,10 +231,10 @@
   /// Prints all timers as JSON key/value pairs.
   static const char *printAllJSONValues(raw_ostream &OS, const char *delim);
 
-  /// Ensure global timer group lists are initialized. This function is mostly
-  /// used by the Statistic code to influence the construction and destruction
-  /// order of the global timer lists.
-  static void ConstructTimerLists();
+  /// Ensure global objects required for statistics printing are initialized.
+  /// This function is used by the Statistic code to ensure correct order of
+  /// global constructors and destructors.
+  static void ConstructForStatistics();
 
   /// This makes the default group unmanaged, and lets the user manage the
   /// group's lifetime.


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