Fix PR 23499 - Avoid multiple profile counters for functions in comdat sections.

Counter symbols created for linkonce functions are not discarded by ELF
linkers unless the symbols are placed in the same comdat section as its
associated function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238335 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Instrumentation/InstrProfiling.cpp b/lib/Transforms/Instrumentation/InstrProfiling.cpp
index 0718ddcb6ec75dfde2c0af3c4b4975ebb8c084f6..610ff52ba9db0c3cd5ab8e67a49a4248710c61eb 100644 (file)
--- a/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ b/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -203,6 +203,7 @@ InstrProfiling::getOrCreateRegionCounters(InstrProfIncrementInst *Inc) {
   uint64_t NumCounters = Inc->getNumCounters()->getZExtValue();
   LLVMContext &Ctx = M->getContext();
   ArrayType *CounterTy = ArrayType::get(Type::getInt64Ty(Ctx), NumCounters);
+  Function *Fn = Inc->getParent()->getParent();
 
   // Create the counters variable.
   auto *Counters = new GlobalVariable(*M, CounterTy, false, Name->getLinkage(),
@@ -211,6 +212,10 @@ InstrProfiling::getOrCreateRegionCounters(InstrProfIncrementInst *Inc) {
   Counters->setVisibility(Name->getVisibility());
   Counters->setSection(getCountersSection());
   Counters->setAlignment(8);
+  // Place the counters in the same comdat section as its parent function.
+  // Otherwise, we may get multiple counters for the same function in certain
+  // cases.
+  Counters->setComdat(Fn->getComdat());
 
   RegionCounters[Inc->getName()] = Counters;
 
@@ -235,6 +240,7 @@ InstrProfiling::getOrCreateRegionCounters(InstrProfIncrementInst *Inc) {
   Data->setVisibility(Name->getVisibility());
   Data->setSection(getDataSection());
   Data->setAlignment(8);
+  Data->setComdat(Fn->getComdat());
 
   // Mark the data variable as used so that it isn't stripped out.
   UsedVars.push_back(Data);