Make getParamAlignment use argument numbers

The method is called "get *Param* Alignment", and is only used for
return values exactly once, so it should take argument indices, not
attribute indices.

Avoids confusing code like:
  IsSwiftError = CS->paramHasAttr(ArgIdx, Attribute::SwiftError);
  Alignment  = CS->getParamAlignment(ArgIdx + 1);

Add getRetAlignment to handle the one case in Value.cpp that wants the
return value alignment.

This is a potentially breaking change for out-of-tree backends that do
their own call lowering.

llvm-svn: 301682

1 files changed, 6 insertions, 2 deletions

diff --git a/llvm/lib/IR/Attributes.cpp b/llvm/lib/IR/Attributes.cpp
index f0db6b4e71a..62f127bd02e 100644
--- a/llvm/lib/IR/Attributes.cpp
+++ b/llvm/lib/IR/Attributes.cpp
@@ -1191,8 +1191,12 @@ Attribute AttributeList::getAttribute(unsigned Index, StringRef Kind) const {
   return getAttributes(Index).getAttribute(Kind);
 }
 
-unsigned AttributeList::getParamAlignment(unsigned Index) const {
-  return getAttributes(Index).getAlignment();
+unsigned AttributeList::getRetAlignment() const {
+  return getAttributes(ReturnIndex).getAlignment();
+}
+
+unsigned AttributeList::getParamAlignment(unsigned ArgNo) const {
+  return getAttributes(ArgNo + 1).getAlignment();
 }
 
 unsigned AttributeList::getStackAlignment(unsigned Index) const {