ASan: use getTypeAllocSize instead of getTypeStoreSize.

This change replaces getTypeStoreSize with getTypeAllocSize in AddressSanitizer
instrumentation for stack allocations.

One case where old behaviour produced undesired results is an optimization in
InstCombine pass (PromoteCastOfAllocation), which can replace  alloca(T) with
alloca(S), where S has the same AllocSize, but a smaller StoreSize. Another
case is memcpy(long double => long double), where ASan will poison bytes 10-15
of a stack-allocated long double (StoreSize  10, AllocSize 16,
sizeof(long double) = 16).

See http://llvm.org/bugs/show_bug.cgi?id=12047 for more context.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151887 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index ce5d43a68f..123e399042 100644
--- a/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -167,7 +167,7 @@ struct AddressSanitizer : public ModulePass {
 
   uint64_t getAllocaSizeInBytes(AllocaInst *AI) {
     Type *Ty = AI->getAllocatedType();
-    uint64_t SizeInBytes = TD->getTypeStoreSizeInBits(Ty) / 8;
+    uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
     return SizeInBytes;
   }
   uint64_t getAlignedSize(uint64_t SizeInBytes) {