When a function takes a variable number of pointer arguments, with a zero
pointer marking the end of the list, the zero *must* be cast to the pointer
type. An un-cast zero is a 32-bit int, and at least on x86_64, gcc will
not extend the zero to 64 bits, thus allowing the upper 32 bits to be
random junk.
The new END_WITH_NULL macro may be used to annotate a such a function
so that GCC (version 4 or newer) will detect the use of un-casted zero
at compile time.
llvm-svn: 23888
diff --git a/llvm/lib/Transforms/Scalar/LowerAllocations.cpp b/llvm/lib/Transforms/Scalar/LowerAllocations.cpp
index 1502fab..f1721b3 100644
--- a/llvm/lib/Transforms/Scalar/LowerAllocations.cpp
+++ b/llvm/lib/Transforms/Scalar/LowerAllocations.cpp
@@ -83,7 +83,7 @@
MallocFunc = M.getOrInsertFunction("malloc", FT);
}
if (FreeFunc == 0)
- FreeFunc = M.getOrInsertFunction("free" , Type::VoidTy, SBPTy, 0);
+ FreeFunc = M.getOrInsertFunction("free" , Type::VoidTy, SBPTy, (Type *)0);
return true;
}