[SanitizerCoverage] Make Inline8bit and TracePC counters dead stripping resistant.

Summary:
Otherwise, at least on Mac, the linker eliminates unused symbols which
causes libFuzzer to error out due to a mismatch of the sizes of coverage tables.

Issue in Chromium: https://bugs.chromium.org/p/chromium/issues/detail?id=892167

Reviewers: morehouse, kcc, george.karpenkov

Reviewed By: morehouse

Subscribers: kubamracek, llvm-commits

Differential Revision: https://reviews.llvm.org/D53113

llvm-svn: 344345

diff --git a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
index 2a05592..bf461c6 100644 (file)
--- a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -594,6 +594,7 @@ GlobalVariable *SanitizerCoverageModule::CreateFunctionLocalArrayInSection(
   Array->setSection(getSectionName(Section));
   Array->setAlignment(Ty->isPointerTy() ? DL->getPointerSize()
                                         : Ty->getPrimitiveSizeInBits() / 8);
+  GlobalsToAppendToUsed.push_back(Array);
   GlobalsToAppendToCompilerUsed.push_back(Array);
   MDNode *MD = MDNode::get(F.getContext(), ValueAsMetadata::get(&F));
   Array->addMetadata(LLVMContext::MD_associated, *MD);
@@ -631,14 +632,14 @@ SanitizerCoverageModule::CreatePCArray(Function &F,
 
 void SanitizerCoverageModule::CreateFunctionLocalArrays(
     Function &F, ArrayRef<BasicBlock *> AllBlocks) {
-  if (Options.TracePCGuard) {
+  if (Options.TracePCGuard)
     FunctionGuardArray = CreateFunctionLocalArrayInSection(
         AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName);
-    GlobalsToAppendToUsed.push_back(FunctionGuardArray);
-  }
+
   if (Options.Inline8bitCounters)
     Function8bitCounterArray = CreateFunctionLocalArrayInSection(
         AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName);
+
   if (Options.PCTable)
     FunctionPCsArray = CreatePCArray(F, AllBlocks);
 }