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/examples/HowToUseJIT/HowToUseJIT.cpp b/examples/HowToUseJIT/HowToUseJIT.cpp
index 192c76d..5ba8a7f 100644
--- a/examples/HowToUseJIT/HowToUseJIT.cpp
+++ b/examples/HowToUseJIT/HowToUseJIT.cpp
@@ -51,7 +51,8 @@ int main() {
   // Create the add1 function entry and insert this entry into module M.  The
   // function will have a return type of "int" and take an argument of "int".
   // The '0' terminates the list of argument types.
-  Function *Add1F = M->getOrInsertFunction("add1", Type::IntTy, Type::IntTy, 0);
+  Function *Add1F = M->getOrInsertFunction("add1", Type::IntTy, Type::IntTy,
+                                           (Type *)0);
 
   // Add a basic block to the function. As before, it automatically inserts
   // because of the last argument.
@@ -76,7 +77,7 @@ int main() {
 
   // Now we going to create function `foo', which returns an int and takes no
   // arguments.
-  Function *FooF = M->getOrInsertFunction("foo", Type::IntTy, 0);
+  Function *FooF = M->getOrInsertFunction("foo", Type::IntTy, (Type *)0);
 
   // Add a basic block to the FooF function.
   BB = new BasicBlock("EntryBlock", FooF);