PNaCl: Add ExpandSmallArguments pass to widen parameters to 32 bits

This widens i1, i8 and i16 function arguments and return types.

Factor out RecreateFunction() helper function from existing PNaCl
passes since this is a reoccurring code fragment.

BUG=https://code.google.com/p/nativeclient/issues/detail?id=3342
TEST=*.ll tests + PNaCl toolchain trybots + GCC torture tests + LLVM test suite

Review URL: https://codereview.chromium.org/15971007

1 files changed, 1 insertions, 11 deletions

diff --git a/lib/Transforms/NaCl/ExpandVarArgs.cpp b/lib/Transforms/NaCl/ExpandVarArgs.cpp
index 3ea093f8f8..36f58416e2 100644
--- a/lib/Transforms/NaCl/ExpandVarArgs.cpp
+++ b/lib/Transforms/NaCl/ExpandVarArgs.cpp
@@ -72,15 +72,7 @@ static void ExpandVarArgFunc(Function *Func) {
   SmallVector<Type *, 8> Params(FTy->param_begin(), FTy->param_end());
   Params.push_back(PtrType);
   FunctionType *NFTy = FunctionType::get(FTy->getReturnType(), Params, false);
-
-  // In order to change the function's arguments, we have to recreate
-  // the function.
-  Function *NewFunc = Function::Create(NFTy, Func->getLinkage());
-  NewFunc->copyAttributesFrom(Func);
-  Func->getParent()->getFunctionList().insert(Func, NewFunc);
-  NewFunc->takeName(Func);
-  NewFunc->getBasicBlockList().splice(NewFunc->begin(),
-                                      Func->getBasicBlockList());
+  Function *NewFunc = RecreateFunction(Func, NFTy);
 
   // Declare the new argument as "noalias".
   NewFunc->setAttributes(
@@ -95,8 +87,6 @@ static void ExpandVarArgFunc(Function *Func) {
     NewArg->takeName(Arg);
   }
 
-  Func->replaceAllUsesWith(
-      ConstantExpr::getBitCast(NewFunc, FTy->getPointerTo()));
   Func->eraseFromParent();
 
   Value *VarArgsArg = --NewFunc->arg_end();