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

2 files changed, 7 insertions, 5 deletions

diff --git a/llvm/lib/Bytecode/Reader/Reader.cpp b/llvm/lib/Bytecode/Reader/Reader.cpp
index ba9c6ca97f6..daf7577cf00 100644
--- a/llvm/lib/Bytecode/Reader/Reader.cpp
+++ b/llvm/lib/Bytecode/Reader/Reader.cpp
@@ -680,7 +680,8 @@ void BytecodeReader::ParseInstruction(std::vector<unsigned> &Oprnds,
     break;
   case 32: { //VANext_old
     const Type* ArgTy = getValue(iType, Oprnds[0])->getType();
-    Function* NF = TheModule->getOrInsertFunction("llvm.va_copy", ArgTy, ArgTy, 0);
+    Function* NF = TheModule->getOrInsertFunction("llvm.va_copy", ArgTy, ArgTy,
+                                                  (Type *)0);
 
     //b = vanext a, t ->
     //foo = alloca 1 of t
@@ -700,7 +701,8 @@ void BytecodeReader::ParseInstruction(std::vector<unsigned> &Oprnds,
   }
   case 33: { //VAArg_old
     const Type* ArgTy = getValue(iType, Oprnds[0])->getType();
-    Function* NF = TheModule->getOrInsertFunction("llvm.va_copy", ArgTy, ArgTy, 0);
+    Function* NF = TheModule->getOrInsertFunction("llvm.va_copy", ArgTy, ArgTy,
+                                                  (Type *)0);
 
     //b = vaarg a, t ->
     //foo = alloca 1 of t
diff --git a/llvm/lib/Bytecode/Reader/ReaderWrappers.cpp b/llvm/lib/Bytecode/Reader/ReaderWrappers.cpp
index 4db954a3078..1ee27185add 100644
--- a/llvm/lib/Bytecode/Reader/ReaderWrappers.cpp
+++ b/llvm/lib/Bytecode/Reader/ReaderWrappers.cpp
@@ -181,7 +181,7 @@ static ModuleProvider* CheckVarargs(ModuleProvider* MP) {
     const Type* ArgTy = F->getFunctionType()->getReturnType();
     const Type* ArgTyPtr = PointerType::get(ArgTy);
     Function* NF = M->getOrInsertFunction("llvm.va_start",
-                                               RetTy, ArgTyPtr, 0);
+                                          RetTy, ArgTyPtr, (Type *)0);
 
     for(Value::use_iterator I = F->use_begin(), E = F->use_end(); I != E;)
       if (CallInst* CI = dyn_cast<CallInst>(*I++)) {
@@ -204,7 +204,7 @@ static ModuleProvider* CheckVarargs(ModuleProvider* MP) {
     const Type* ArgTy = F->getFunctionType()->getParamType(0);
     const Type* ArgTyPtr = PointerType::get(ArgTy);
     Function* NF = M->getOrInsertFunction("llvm.va_end",
-                                                 RetTy, ArgTyPtr, 0);
+                                          RetTy, ArgTyPtr, (Type *)0);
 
     for(Value::use_iterator I = F->use_begin(), E = F->use_end(); I != E;)
       if (CallInst* CI = dyn_cast<CallInst>(*I++)) {
@@ -230,7 +230,7 @@ static ModuleProvider* CheckVarargs(ModuleProvider* MP) {
     const Type* ArgTy = F->getFunctionType()->getReturnType();
     const Type* ArgTyPtr = PointerType::get(ArgTy);
     Function* NF = M->getOrInsertFunction("llvm.va_copy",
-                                          RetTy, ArgTyPtr, ArgTyPtr, 0);
+                                          RetTy, ArgTyPtr, ArgTyPtr, (Type *)0);
 
     for(Value::use_iterator I = F->use_begin(), E = F->use_end(); I != E;)
       if (CallInst* CI = dyn_cast<CallInst>(*I++)) {