IR: add optional type to 'byval' function parameters

When we switch to opaque pointer types we will need some way to describe
how many bytes a 'byval' parameter should occupy on the stack. This adds
a (for now) optional extra type parameter.

If present, the type must match the pointee type of the argument.

Note to front-end maintainers: if this causes test failures, it's probably
because the "byval" attribute is printed after attributes without any parameter
after this change.

llvm-svn: 362012

1 files changed, 5 insertions, 3 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
index 8fb1a7b..d887ed7 100644
--- a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -1204,9 +1204,11 @@ bool FastISel::lowerCallTo(CallLoweringInfo &CLI) {
     if (Arg.IsByVal || Arg.IsInAlloca) {
       PointerType *Ty = cast<PointerType>(Arg.Ty);
       Type *ElementTy = Ty->getElementType();
-      unsigned FrameSize = DL.getTypeAllocSize(ElementTy);
-      // For ByVal, alignment should come from FE. BE will guess if this info is
-      // not there, but there are cases it cannot get right.
+      unsigned FrameSize =
+          DL.getTypeAllocSize(Arg.ByValType ? Arg.ByValType : ElementTy);
+
+      // For ByVal, alignment should come from FE. BE will guess if this info
+      // is not there, but there are cases it cannot get right.
       unsigned FrameAlign = Arg.Alignment;
       if (!FrameAlign)
         FrameAlign = TLI.getByValTypeAlignment(ElementTy, DL);