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

1 files changed, 3 insertions, 2 deletions

diff --git a/lib/Transforms/IPO/SimplifyLibCalls.cpp b/lib/Transforms/IPO/SimplifyLibCalls.cpp
index 58aac20b70..63ab333430 100644
--- a/lib/Transforms/IPO/SimplifyLibCalls.cpp
+++ b/lib/Transforms/IPO/SimplifyLibCalls.cpp
@@ -311,7 +311,8 @@ public:
     if (!memcpy_func) {
       const Type *SBP = PointerType::get(Type::SByteTy);
       memcpy_func = M->getOrInsertFunction("llvm.memcpy", Type::VoidTy,SBP, SBP,
-                                           Type::UIntTy, Type::UIntTy, 0);
+                                           Type::UIntTy, Type::UIntTy,
+                                           (Type *)0);
     }
     return memcpy_func;
   }
@@ -319,7 +320,7 @@ public:
   Function* get_floorf() {
     if (!floorf_func)
       floorf_func = M->getOrInsertFunction("floorf", Type::FloatTy,
-                                           Type::FloatTy, 0);
+                                           Type::FloatTy, (Type *)0);
     return floorf_func;
   }