[SanitizerCoverage] Don't add instrumentation to unreachable blocks.
llvm-svn: 241127
diff --git a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
index dff39ef..7a5b4cb 100644
--- a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -375,6 +375,13 @@
void SanitizerCoverageModule::InjectCoverageAtBlock(Function &F, BasicBlock &BB,
bool UseCalls) {
+ // Don't insert coverage for unreachable blocks: we will never call
+ // __sanitizer_cov() for them, so counting them in
+ // NumberOfInstrumentedBlocks() might complicate calculation of code coverage
+ // percentage. Also, unreachable instructions frequently have no debug
+ // locations.
+ if (isa<UnreachableInst>(BB.getTerminator()))
+ return;
BasicBlock::iterator IP = BB.getFirstInsertionPt(), BE = BB.end();
// Skip static allocas at the top of the entry block so they don't become
// dynamic when we split the block. If we used our optimized stack layout,