[llvm] [Coroutines] fix coroutines + std::unique_ptr with async exceptions validation errors (PR #149691)

[Weibo He via llvm-commits]

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@@ -973,6 +975,178 @@ static StructType *buildFrameType(Function &F, coro::Shape &Shape,
   return FrameTy;
 }
 
+// This function assumes that it is being called on basic block in reversed
+// post-order, meaning predecessors are visited before successors failing to do
+// so will cause VMap to be non-valid and will cause instructions to fail
+// mapping to their corresponding clones
+static void finalizeBasicBlockCloneAndTrackSuccessors(
+    BasicBlock *InitialBlock, BasicBlock *ClonedBlock, ValueToValueMapTy &VMap,
+    SmallSet<BasicBlock *, 20> &SuccessorBlocksSet) {
+  // This code will examine the basic block, fix issues caused by clones
+  //  for example - tailor cleanupret to the corresponding cleanuppad
+  //  it will use VMap to do so
+  // in addition, it will add the node successors to SuccessorBlocksSet
+
+  // Remap the instructions, VMap here aggregates instructions across
+  // multiple BasicBlocks, and we assume that traversal is reversed post-order,
+  // therefore successor blocks (for example instructions having funclet
+  // tags) will be mapped correctly to the new cloned cleanuppad
+  for (Instruction &ClonedBlockInstruction : *ClonedBlock) {
+    RemapInstruction(&ClonedBlockInstruction, VMap,
+                     RF_NoModuleLevelChanges | RF_IgnoreMissingLocals);
+  }
+
+  const auto &InitialBlockTerminator = InitialBlock->getTerminator();
+
+  // If it's cleanupret, find the correspondant cleanuppad (use the VMap to
+  // find it).
+  if (auto *InitialBlockTerminatorCleanupReturn =
+          dyn_cast<CleanupReturnInst>(InitialBlockTerminator)) {
+    // if none found do nothing
+    if (VMap.find(InitialBlockTerminatorCleanupReturn->getCleanupPad()) ==
+        VMap.end()) {
+      return;
+    }
+
+    auto *ClonedBlockTerminatorCleanupReturn =
+        cast<CleanupReturnInst>(ClonedBlock->getTerminator());
+
+    // Assuming reversed post-order traversal
+    llvm::Value *ClonedBlockCleanupPadValue =
+        VMap[InitialBlockTerminatorCleanupReturn->getCleanupPad()];
+    auto *ClonedBlockCleanupPad =
+        cast<CleanupPadInst>(ClonedBlockCleanupPadValue);
+    ClonedBlockTerminatorCleanupReturn->setCleanupPad(ClonedBlockCleanupPad);
+
+    // If it's a branch/invoke, keep track of its successors, we want to
+    // calculate dominance between CoroBegin and them also
+  } else if (auto *InitialBlockTerminatorBranch =
+                 dyn_cast<BranchInst>(InitialBlockTerminator)) {
+    for (unsigned int successorIdx = 0;
+         successorIdx < InitialBlockTerminatorBranch->getNumSuccessors();
+         ++successorIdx) {
+      SuccessorBlocksSet.insert(
+          InitialBlockTerminatorBranch->getSuccessor(successorIdx));
+    }
+  } else if (auto *InitialBlockTerminatorInvoke =
+                 dyn_cast<InvokeInst>(InitialBlockTerminator)) {
+    SuccessorBlocksSet.insert(InitialBlockTerminatorInvoke->getUnwindDest());
+  } else if (isa<ReturnInst>(InitialBlockTerminator)) {
+    // No action needed
+  } else {
+    InitialBlockTerminator->print(dbgs());
+    report_fatal_error("Terminator is not implemented in "
+                       "finalizeBasicBlockCloneAndTrackSuccessors");
+  }
+}
+
+// Dominance issue fixer for each predecessor satisfying predicate function
+void splitIfBasicBlockPredecessors(
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NewSigma wrote:

static void

https://github.com/llvm/llvm-project/pull/149691