[PATCH] D120218: [BOLT][NFC] Fix data race in ShrinkWrapping stats

[Amir Ayupov via Phabricator via llvm-commits]

Amir created this revision.
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Fix data race reported by ThreadSanitizer in clang.test:

  ThreadSanitizer: data race /data/llvm-project/bolt/lib/Passes/ShrinkWrapping.cpp:1359:28
  in llvm::bolt::ShrinkWrapping::moveSaveRestores()

The issue is with incrementing global counters from multiple threads.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D120218

Files:
  bolt/include/bolt/Passes/ShrinkWrapping.h
  bolt/lib/Passes/ShrinkWrapping.cpp


Index: bolt/lib/Passes/ShrinkWrapping.cpp
===================================================================
--- bolt/lib/Passes/ShrinkWrapping.cpp
+++ bolt/lib/Passes/ShrinkWrapping.cpp
@@ -710,8 +710,8 @@
   IsInitialized = true;
 }
 
-uint64_t ShrinkWrapping::SpillsMovedRegularMode = 0;
-uint64_t ShrinkWrapping::SpillsMovedPushPopMode = 0;
+std::atomic_uint64_t ShrinkWrapping::SpillsMovedRegularMode{0};
+std::atomic_uint64_t ShrinkWrapping::SpillsMovedPushPopMode{0};
 
 using BBIterTy = BinaryBasicBlock::iterator;
 
Index: bolt/include/bolt/Passes/ShrinkWrapping.h
===================================================================
--- bolt/include/bolt/Passes/ShrinkWrapping.h
+++ bolt/include/bolt/Passes/ShrinkWrapping.h
@@ -308,8 +308,8 @@
   std::vector<MCInst *> BestSavePos;
 
   /// Pass stats
-  static uint64_t SpillsMovedRegularMode;
-  static uint64_t SpillsMovedPushPopMode;
+  static std::atomic_uint64_t SpillsMovedRegularMode;
+  static std::atomic_uint64_t SpillsMovedPushPopMode;
 
   Optional<unsigned> AnnotationIndex;
 


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