[WinEH] Update catchrets with cloned successors

Summary:
Add a pass to update catchrets when their successors get cloned; the
existing pass doesn't catch these because it walks the funclet whose
blocks are being cloned but the catchret is in a child funclet.

Also update the test for removing incoming PHI values; when the
predecessor is a catchret, the relevant color is the catchret's parentPad,
not its block's color.


Reviewers: andrew.w.kaylor, rnk, majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D15840

llvm-svn: 256689

1 files changed, 38 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/WinEHPrepare.cpp b/llvm/lib/CodeGen/WinEHPrepare.cpp
index 83507894b49..3d1c3803194 100644
--- a/llvm/lib/CodeGen/WinEHPrepare.cpp
+++ b/llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -598,6 +598,11 @@ void WinEHPrepare::cloneCommonBlocks(Function &F) {
   for (auto &Funclets : FuncletBlocks) {
     BasicBlock *FuncletPadBB = Funclets.first;
     std::vector<BasicBlock *> &BlocksInFunclet = Funclets.second;
+    Value *FuncletToken;
+    if (FuncletPadBB == &F.getEntryBlock())
+      FuncletToken = ConstantTokenNone::get(F.getContext());
+    else
+      FuncletToken = FuncletPadBB->getFirstNonPHI();
 
     std::vector<std::pair<BasicBlock *, BasicBlock *>> Orig2Clone;
     ValueToValueMapTy VMap;
@@ -669,15 +674,44 @@ void WinEHPrepare::cloneCommonBlocks(Function &F) {
         RemapInstruction(&I, VMap,
                          RF_IgnoreMissingEntries | RF_NoModuleLevelChanges);
 
+    // Catchrets targeting cloned blocks need to be updated separately from
+    // the loop above because they are not in the current funclet.
+    SmallVector<CatchReturnInst *, 2> FixupCatchrets;
+    for (auto &BBMapping : Orig2Clone) {
+      BasicBlock *OldBlock = BBMapping.first;
+      BasicBlock *NewBlock = BBMapping.second;
+
+      FixupCatchrets.clear();
+      for (BasicBlock *Pred : predecessors(OldBlock))
+        if (auto *CatchRet = dyn_cast<CatchReturnInst>(Pred->getTerminator()))
+          if (CatchRet->getParentPad() == FuncletToken)
+            FixupCatchrets.push_back(CatchRet);
+
+      for (CatchReturnInst *CatchRet : FixupCatchrets)
+        CatchRet->setSuccessor(NewBlock);
+    }
+
     auto UpdatePHIOnClonedBlock = [&](PHINode *PN, bool IsForOldBlock) {
       unsigned NumPreds = PN->getNumIncomingValues();
       for (unsigned PredIdx = 0, PredEnd = NumPreds; PredIdx != PredEnd;
            ++PredIdx) {
         BasicBlock *IncomingBlock = PN->getIncomingBlock(PredIdx);
-        ColorVector &IncomingColors = BlockColors[IncomingBlock];
-        bool BlockInFunclet = IncomingColors.size() == 1 &&
-                              IncomingColors.front() == FuncletPadBB;
-        if (IsForOldBlock != BlockInFunclet)
+        bool EdgeTargetsFunclet;
+        if (auto *CRI =
+                dyn_cast<CatchReturnInst>(IncomingBlock->getTerminator())) {
+          EdgeTargetsFunclet = (CRI->getParentPad() == FuncletToken);
+        } else {
+          ColorVector &IncomingColors = BlockColors[IncomingBlock];
+          assert(!IncomingColors.empty() && "Block not colored!");
+          assert((IncomingColors.size() == 1 ||
+                  llvm::all_of(IncomingColors,
+                               [&](BasicBlock *Color) {
+                                 return Color != FuncletPadBB;
+                               })) &&
+                 "Cloning should leave this funclet's blocks monochromatic");
+          EdgeTargetsFunclet = (IncomingColors.front() == FuncletPadBB);
+        }
+        if (IsForOldBlock != EdgeTargetsFunclet)
           continue;
         PN->removeIncomingValue(IncomingBlock, /*DeletePHIIfEmpty=*/false);
         // Revisit the next entry.