[llvm-commits] [llvm] r151887 - /llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp

[Evgeniy Stepanov]

Author: eugenis
Date: Fri Mar  2 04:41:08 2012
New Revision: 151887

URL: http://llvm.org/viewvc/llvm-project?rev=151887&view=rev
Log:
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.


Modified:
    llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp

Modified: llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp?rev=151887&r1=151886&r2=151887&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp Fri Mar  2 04:41:08 2012
@@ -167,7 +167,7 @@
 
   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) {