[WinEH] Rename CatchReturnInst::getParentPad, NFC

Summary:
Rename to getCatchSwitchParentPad, to make it more clear which ancestor
the "parent" in question is.  Add a comment pointing out the key feature
that the returned pad indicates which funclet contains the successor
block.

Reviewers: rnk, andrew.w.kaylor, majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D16222

llvm-svn: 257933

Author: JosephTremoulet

llvm/include/llvm/IR/Instructions.h

@@ -4152,7 +4152,9 @@ class CatchReturnInst : public TerminatorInst {
   }
   unsigned getNumSuccessors() const { return 1; }
 
-  Value *getParentPad() const {
+  /// Get the parentPad of this catchret's catchpad's catchswitch.
+  /// The successor block is implicitly a member of this funclet.
+  Value *getCatchSwitchParentPad() const {
     return getCatchPad()->getCatchSwitch()->getParentPad();
   }
 

llvm/lib/Analysis/EHPersonalities.cpp

@@ -92,7 +92,7 @@ DenseMap<BasicBlock *, ColorVector> llvm::colorEHFunclets(Function &F) {
     BasicBlock *SuccColor = Color;
     TerminatorInst *Terminator = Visiting->getTerminator();
     if (auto *CatchRet = dyn_cast<CatchReturnInst>(Terminator)) {
-      Value *ParentPad = CatchRet->getParentPad();
+      Value *ParentPad = CatchRet->getCatchSwitchParentPad();
       if (isa<ConstantTokenNone>(ParentPad))
         SuccColor = EntryBlock;
       else

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -1206,7 +1206,7 @@ void SelectionDAGBuilder::visitCatchRet(const CatchReturnInst &I) {
   // This will be used by the FuncletLayout pass to determine how to order the
   // BB's.
   // A 'catchret' returns to the outer scope's color.
-  Value *ParentPad = I.getParentPad();
+  Value *ParentPad = I.getCatchSwitchParentPad();
   const BasicBlock *SuccessorColor;
   if (isa<ConstantTokenNone>(ParentPad))
     SuccessorColor = &FuncInfo.Fn->getEntryBlock();

llvm/lib/CodeGen/WinEHPrepare.cpp

@@ -787,7 +787,7 @@ void WinEHPrepare::cloneCommonBlocks(Function &F) {
       FixupCatchrets.clear();
       for (BasicBlock *Pred : predecessors(OldBlock))
         if (auto *CatchRet = dyn_cast<CatchReturnInst>(Pred->getTerminator()))
-          if (CatchRet->getParentPad() == FuncletToken)
+          if (CatchRet->getCatchSwitchParentPad() == FuncletToken)
             FixupCatchrets.push_back(CatchRet);
 
       for (CatchReturnInst *CatchRet : FixupCatchrets)
@@ -802,7 +802,7 @@ void WinEHPrepare::cloneCommonBlocks(Function &F) {
         bool EdgeTargetsFunclet;
         if (auto *CRI =
                 dyn_cast<CatchReturnInst>(IncomingBlock->getTerminator())) {
-          EdgeTargetsFunclet = (CRI->getParentPad() == FuncletToken);
+          EdgeTargetsFunclet = (CRI->getCatchSwitchParentPad() == FuncletToken);
         } else {
           ColorVector &IncomingColors = BlockColors[IncomingBlock];
           assert(!IncomingColors.empty() && "Block not colored!");