96 lines · cpp
1//===- LowerInvoke.cpp - Eliminate Invoke instructions --------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// This transformation is designed for use by code generators which do not yet10// support stack unwinding. This pass converts 'invoke' instructions to 'call'11// instructions, so that any exception-handling 'landingpad' blocks become dead12// code (which can be removed by running the '-simplifycfg' pass afterwards).13//14//===----------------------------------------------------------------------===//15 16#include "llvm/Transforms/Utils/LowerInvoke.h"17#include "llvm/ADT/SmallVector.h"18#include "llvm/ADT/Statistic.h"19#include "llvm/IR/Instructions.h"20#include "llvm/InitializePasses.h"21#include "llvm/Pass.h"22#include "llvm/Transforms/Utils.h"23using namespace llvm;24 25#define DEBUG_TYPE "lower-invoke"26 27STATISTIC(NumInvokes, "Number of invokes replaced");28 29namespace {30class LowerInvokeLegacyPass : public FunctionPass {31public:32 static char ID; // Pass identification, replacement for typeid33 explicit LowerInvokeLegacyPass() : FunctionPass(ID) {34 initializeLowerInvokeLegacyPassPass(*PassRegistry::getPassRegistry());35 }36 bool runOnFunction(Function &F) override;37};38} // namespace39 40char LowerInvokeLegacyPass::ID = 0;41INITIALIZE_PASS(LowerInvokeLegacyPass, "lowerinvoke",42 "Lower invoke and unwind, for unwindless code generators",43 false, false)44 45static bool runImpl(Function &F) {46 bool Changed = false;47 for (BasicBlock &BB : F)48 if (InvokeInst *II = dyn_cast<InvokeInst>(BB.getTerminator())) {49 SmallVector<Value *, 16> CallArgs(II->args());50 SmallVector<OperandBundleDef, 1> OpBundles;51 II->getOperandBundlesAsDefs(OpBundles);52 // Insert a normal call instruction...53 CallInst *NewCall =54 CallInst::Create(II->getFunctionType(), II->getCalledOperand(),55 CallArgs, OpBundles, "", II->getIterator());56 NewCall->takeName(II);57 NewCall->setCallingConv(II->getCallingConv());58 NewCall->setAttributes(II->getAttributes());59 NewCall->setDebugLoc(II->getDebugLoc());60 II->replaceAllUsesWith(NewCall);61 62 // Insert an unconditional branch to the normal destination.63 BranchInst::Create(II->getNormalDest(), II->getIterator());64 65 // Remove any PHI node entries from the exception destination.66 II->getUnwindDest()->removePredecessor(&BB);67 68 // Remove the invoke instruction now.69 II->eraseFromParent();70 71 ++NumInvokes;72 Changed = true;73 }74 return Changed;75}76 77bool LowerInvokeLegacyPass::runOnFunction(Function &F) {78 return runImpl(F);79}80 81char &llvm::LowerInvokePassID = LowerInvokeLegacyPass::ID;82 83// Public Interface To the LowerInvoke pass.84FunctionPass *llvm::createLowerInvokePass() {85 return new LowerInvokeLegacyPass();86}87 88PreservedAnalyses LowerInvokePass::run(Function &F,89 FunctionAnalysisManager &AM) {90 bool Changed = runImpl(F);91 if (!Changed)92 return PreservedAnalyses::all();93 94 return PreservedAnalyses::none();95}96