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

1 files changed, 6 insertions, 5 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/TraceValues.cpp b/llvm/lib/Transforms/Instrumentation/TraceValues.cpp
index 9838ea101ac..eba596b4274 100644
--- a/llvm/lib/Transforms/Instrumentation/TraceValues.cpp
+++ b/llvm/lib/Transforms/Instrumentation/TraceValues.cpp
@@ -130,17 +130,18 @@ void ExternalFuncs::doInitialization(Module &M) {
 
   // uint (sbyte*)
   HashPtrFunc = M.getOrInsertFunction("HashPointerToSeqNum", Type::UIntTy, SBP,
-                                      0);
+                                      (Type *)0);
 
   // void (sbyte*)
   ReleasePtrFunc = M.getOrInsertFunction("ReleasePointerSeqNum",
-                                         Type::VoidTy, SBP, 0);
+                                         Type::VoidTy, SBP, (Type *)0);
   RecordPtrFunc  = M.getOrInsertFunction("RecordPointer",
-                                         Type::VoidTy, SBP, 0);
+                                         Type::VoidTy, SBP, (Type *)0);
 
-  PushOnEntryFunc = M.getOrInsertFunction("PushPointerSet", Type::VoidTy, 0);
+  PushOnEntryFunc = M.getOrInsertFunction("PushPointerSet", Type::VoidTy,
+                                          (Type *)0);
   ReleaseOnReturnFunc = M.getOrInsertFunction("ReleasePointersPopSet",
-                                              Type::VoidTy, 0);
+                                              Type::VoidTy, (Type *)0);
 }