[PATCH] D56516: [SanitizerCoverage] Don't create comdat for weak functions.

[Matt Morehouse via Phabricator via llvm-commits]

morehouse created this revision.
morehouse added reviewers: eugenis, pcc.
Herald added a subscriber: hiraditya.

Comdat groups override weak symbol behavior, allowing the linker to keep
the comdats for weak symbols in favor of comdats for strong symbols.

Fixes the issue described in:
https://bugs.chromium.org/p/chromium/issues/detail?id=918662#c24


https://reviews.llvm.org/D56516

Files:
  llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp


Index: llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
===================================================================
--- llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -577,7 +577,7 @@
       *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage,
       Constant::getNullValue(ArrayTy), "__sancov_gen_");
 
-  if (TargetTriple.supportsCOMDAT())
+  if (TargetTriple.supportsCOMDAT() && !F.hasWeakLinkage())
     if (auto Comdat =
             GetOrCreateFunctionComdat(F, TargetTriple, CurModuleUniqueId))
       Array->setComdat(Comdat);


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