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, 2 insertions, 1 deletions

diff --git a/llvm/tools/lli/lli.cpp b/llvm/tools/lli/lli.cpp
index bd22b2924bf..c1b7478a376 100644
--- a/llvm/tools/lli/lli.cpp
+++ b/llvm/tools/lli/lli.cpp
@@ -96,7 +96,8 @@ int main(int argc, char **argv, char * const *envp) {
     // If the program didn't explicitly call exit, call exit now, for the program.
     // This ensures that any atexit handlers get called correctly.
     Function *Exit = MP->getModule()->getOrInsertFunction("exit", Type::VoidTy,
-                                                          Type::IntTy, 0);
+                                                          Type::IntTy,
+                                                          (Type *)0);
 
     std::vector<GenericValue> Args;
     GenericValue ResultGV;