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

4 files changed, 11 insertions, 8 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 {
diff --git a/llvm/lib/IR/Function.cpp b/llvm/lib/IR/Function.cpp
index 12f52a3a892..fc61ba7439b 100644
--- a/llvm/lib/IR/Function.cpp
+++ b/llvm/lib/IR/Function.cpp
@@ -84,8 +84,7 @@ bool Argument::hasByValOrInAllocaAttr() const {
 
 unsigned Argument::getParamAlignment() const {
   assert(getType()->isPointerTy() && "Only pointers have alignments");
-  return getParent()->getParamAlignment(getArgNo()+1);
-
+  return getParent()->getParamAlignment(getArgNo());
 }
 
 uint64_t Argument::getDereferenceableBytes() const {
diff --git a/llvm/lib/IR/Value.cpp b/llvm/lib/IR/Value.cpp
index d0e25f35c01..906c5d33535 100644
--- a/llvm/lib/IR/Value.cpp
+++ b/llvm/lib/IR/Value.cpp
@@ -649,7 +649,7 @@ unsigned Value::getPointerAlignment(const DataLayout &DL) const {
         Align = DL.getPrefTypeAlignment(AllocatedType);
     }
   } else if (auto CS = ImmutableCallSite(this))
-    Align = CS.getAttributes().getParamAlignment(AttributeList::ReturnIndex);
+    Align = CS.getAttributes().getRetAlignment();
   else if (const LoadInst *LI = dyn_cast<LoadInst>(this))
     if (MDNode *MD = LI->getMetadata(LLVMContext::MD_align)) {
       ConstantInt *CI = mdconst::extract<ConstantInt>(MD->getOperand(0));
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index b65f3ef386a..29e785b1aa1 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -2772,7 +2772,7 @@ static AttrBuilder getParameterABIAttributes(int I, AttributeList Attrs) {
       Copy.addAttribute(AK);
   }
   if (Attrs.hasParamAttribute(I, Attribute::Alignment))
-    Copy.addAlignmentAttr(Attrs.getParamAlignment(I + 1));
+    Copy.addAlignmentAttr(Attrs.getParamAlignment(I));
   return Copy;
 }
 
@@ -3992,8 +3992,8 @@ void Verifier::visitIntrinsicCallSite(Intrinsic::ID ID, CallSite CS) {
       return isPowerOf2_64(Alignment) && ElementSizeVal.ule(Alignment);
     };
 
-    uint64_t DstAlignment = CS.getParamAlignment(1),
-             SrcAlignment = CS.getParamAlignment(2);
+    uint64_t DstAlignment = CS.getParamAlignment(0),
+             SrcAlignment = CS.getParamAlignment(1);
 
     Assert(IsValidAlignment(DstAlignment),
            "incorrect alignment of the destination argument",