[SanitizerCoverage] Fix wrong pointer type return from CreateSecStartEnd()

[yingcong-wu]

Summary

CreateSecStartEnd() will return pointer to the input type, so when called with CreateSecStartEnd(M, SanCovCFsSectionName, IntptrPtrTy), SecStartEnd.first and SecStartEnd.second will have type IntptrPtrPtrTy, not IntptrPtrTy.

This problem should not impact the functionality and with opaque pointer enable, this will not trigger any alarm. But if runs with -no-opaque-pointers, this mismatch pointer type will cause type check assertion in CallInst::init() to fail.

[MaskRay]

This is correct. The test control-flow.ll incorrectly mixes ptr with typed pointers so the issue is not found. At this point I don't think this is more value adding typed pointer tests...

llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp

if (Ctor && Options.PCTable) {
     auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, IntptrTy);
     FunctionCallee InitFunction = declareSanitizerInitFunction(
         M, SanCovPCsInitName, {IntptrPtrTy, IntptrPtrTy});
     IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator());
     IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second});
   }
 
   if (Ctor && Options.CollectControlFlow) {
-    auto SecStartEnd = CreateSecStartEnd(M, SanCovCFsSectionName, IntptrPtrTy);
+    auto SecStartEnd = CreateSecStartEnd(M, SanCovCFsSectionName, IntptrTy);
     FunctionCallee InitFunction = declareSanitizerInitFunction(
         M, SanCovCFsInitName, {IntptrPtrTy, IntptrPtrTy});
     IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator());
     IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second});
   }
 
   appendToUsed(M, GlobalsToAppendToUsed);
   appendToCompilerUsed(M, GlobalsToAppendToCompilerUsed);