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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23888 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/IntrinsicLowering.cpp b/lib/CodeGen/IntrinsicLowering.cpp
index b2dd57b..a570ef5 100644
--- a/lib/CodeGen/IntrinsicLowering.cpp
+++ b/lib/CodeGen/IntrinsicLowering.cpp
@@ -110,7 +110,8 @@
case Intrinsic::memset:
M.getOrInsertFunction("memset", PointerType::get(Type::SByteTy),
PointerType::get(Type::SByteTy),
- Type::IntTy, (--(--I->arg_end()))->getType(), 0);
+ Type::IntTy, (--(--I->arg_end()))->getType(),
+ (Type *)0);
break;
case Intrinsic::isunordered:
EnsureFunctionExists(M, "isunordered", I->arg_begin(), I->arg_end(),