[llvm] r241127 - [SanitizerCoverage] Don't add instrumentation to unreachable blocks.

[Alexey Samsonov]

Author: samsonov
Date: Tue Jun 30 18:11:45 2015
New Revision: 241127

URL: http://llvm.org/viewvc/llvm-project?rev=241127&view=rev
Log:
[SanitizerCoverage] Don't add instrumentation to unreachable blocks.

Modified:
    llvm/trunk/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
    llvm/trunk/test/Instrumentation/SanitizerCoverage/coverage.ll

Modified: llvm/trunk/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/SanitizerCoverage.cpp?rev=241127&r1=241126&r2=241127&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/SanitizerCoverage.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/SanitizerCoverage.cpp Tue Jun 30 18:11:45 2015
@@ -375,6 +375,13 @@ void SanitizerCoverageModule::SetNoSanit
 
 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,

Modified: llvm/trunk/test/Instrumentation/SanitizerCoverage/coverage.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Instrumentation/SanitizerCoverage/coverage.ll?rev=241127&r1=241126&r2=241127&view=diff
==============================================================================
--- llvm/trunk/test/Instrumentation/SanitizerCoverage/coverage.ll (original)
+++ llvm/trunk/test/Instrumentation/SanitizerCoverage/coverage.ll Tue Jun 30 18:11:45 2015
@@ -119,3 +119,12 @@ entry:
 ; CHECK4: call void @__sanitizer_cov_indir_call16({{.*}},[[CACHE:.*]])
 ; CHECK4-NOT: call void @__sanitizer_cov_indir_call16({{.*}},[[CACHE]])
 ; CHECK4: ret void
+
+define void @call_unreachable() uwtable sanitize_address {
+entry:
+  unreachable
+}
+
+; CHECK4-LABEL: define void @call_unreachable
+; CHECK4-NOT: __sanitizer_cov
+; CHECK4: unreachable