Reapply: 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.

The original commit did not remap byval types when linking modules, which broke
LTO. This version fixes that.

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: 362128

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/IR/Function.cpp b/llvm/lib/IR/Function.cpp
index b00deb677b3..a4a78ca4deb 100644
--- a/llvm/lib/IR/Function.cpp
+++ b/llvm/lib/IR/Function.cpp
@@ -113,6 +113,11 @@ unsigned Argument::getParamAlignment() const {
   return getParent()->getParamAlignment(getArgNo());
 }
 
+Type *Argument::getParamByValType() const {
+  assert(getType()->isPointerTy() && "Only pointers have byval types");
+  return getParent()->getParamByValType(getArgNo());
+}
+
 uint64_t Argument::getDereferenceableBytes() const {
   assert(getType()->isPointerTy() &&
          "Only pointers have dereferenceable bytes");