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

lib/Transforms/Instrumentation/TraceBasicBlocks.cpp

@@ -46,7 +46,7 @@ static void InsertInstrumentationCall (BasicBlock *BB,
                    << "\", \"" << FnName << "\", " << BBNumber << ")\n");
   Module &M = *BB->getParent ()->getParent ();
   Function *InstrFn = M.getOrInsertFunction (FnName, Type::VoidTy,
-                                             Type::UIntTy, 0);
+                                             Type::UIntTy, (Type *)0);
   std::vector<Value*> Args (1);
   Args[0] = ConstantUInt::get (Type::UIntTy, BBNumber);