1 files changed, 96 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Utils/LowerInvoke.cpp b/llvm/lib/Transforms/Utils/LowerInvoke.cpp
new file mode 100644
index 0000000000000..fe67e191dc62a
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+++ b/llvm/lib/Transforms/Utils/LowerInvoke.cpp
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+//===- LowerInvoke.cpp - Eliminate Invoke instructions --------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This transformation is designed for use by code generators which do not yet
+// support stack unwinding.  This pass converts 'invoke' instructions to 'call'
+// instructions, so that any exception-handling 'landingpad' blocks become dead
+// code (which can be removed by running the '-simplifycfg' pass afterwards).
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Utils/LowerInvoke.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Transforms/Utils.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "lowerinvoke"
+
+STATISTIC(NumInvokes, "Number of invokes replaced");
+
+namespace {
+  class LowerInvokeLegacyPass : public FunctionPass {
+  public:
+    static char ID; // Pass identification, replacement for typeid
+    explicit LowerInvokeLegacyPass() : FunctionPass(ID) {
+      initializeLowerInvokeLegacyPassPass(*PassRegistry::getPassRegistry());
+    }
+    bool runOnFunction(Function &F) override;
+  };
+}
+
+char LowerInvokeLegacyPass::ID = 0;
+INITIALIZE_PASS(LowerInvokeLegacyPass, "lowerinvoke",
+                "Lower invoke and unwind, for unwindless code generators",
+                false, false)
+
+static bool runImpl(Function &F) {
+  bool Changed = false;
+  for (BasicBlock &BB : F)
+    if (InvokeInst *II = dyn_cast<InvokeInst>(BB.getTerminator())) {
+      SmallVector<Value *, 16> CallArgs(II->arg_begin(), II->arg_end());
+      SmallVector<OperandBundleDef, 1> OpBundles;
+      II->getOperandBundlesAsDefs(OpBundles);
+      // Insert a normal call instruction...
+      CallInst *NewCall =
+          CallInst::Create(II->getFunctionType(), II->getCalledValue(),
+                           CallArgs, OpBundles, "", II);
+      NewCall->takeName(II);
+      NewCall->setCallingConv(II->getCallingConv());
+      NewCall->setAttributes(II->getAttributes());
+      NewCall->setDebugLoc(II->getDebugLoc());
+      II->replaceAllUsesWith(NewCall);
+
+      // Insert an unconditional branch to the normal destination.
+      BranchInst::Create(II->getNormalDest(), II);
+
+      // Remove any PHI node entries from the exception destination.
+      II->getUnwindDest()->removePredecessor(&BB);
+
+      // Remove the invoke instruction now.
+      BB.getInstList().erase(II);
+
+      ++NumInvokes;
+      Changed = true;
+    }
+  return Changed;
+}
+
+bool LowerInvokeLegacyPass::runOnFunction(Function &F) {
+  return runImpl(F);
+}
+
+namespace llvm {
+char &LowerInvokePassID = LowerInvokeLegacyPass::ID;
+
+// Public Interface To the LowerInvoke pass.
+FunctionPass *createLowerInvokePass() { return new LowerInvokeLegacyPass(); }
+
+PreservedAnalyses LowerInvokePass::run(Function &F,
+                                       FunctionAnalysisManager &AM) {
+  bool Changed = runImpl(F);
+  if (!Changed)
+    return PreservedAnalyses::all();
+
+  return PreservedAnalyses::none();
+}
+}