forked from OSchip/llvm-project
95 lines
3.1 KiB
C++
95 lines
3.1 KiB
C++
//===- LowerInvoke.cpp - Eliminate Invoke instructions --------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This transformation is designed for use by code generators which do not yet
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// support stack unwinding. This pass converts 'invoke' instructions to 'call'
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// instructions, so that any exception-handling 'landingpad' blocks become dead
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// code (which can be removed by running the '-simplifycfg' pass afterwards).
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Utils/LowerInvoke.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/Module.h"
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#include "llvm/Pass.h"
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#include "llvm/Transforms/Scalar.h"
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using namespace llvm;
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#define DEBUG_TYPE "lowerinvoke"
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STATISTIC(NumInvokes, "Number of invokes replaced");
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namespace {
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class LowerInvokeLegacyPass : public FunctionPass {
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public:
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static char ID; // Pass identification, replacement for typeid
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explicit LowerInvokeLegacyPass() : FunctionPass(ID) {
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initializeLowerInvokeLegacyPassPass(*PassRegistry::getPassRegistry());
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}
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bool runOnFunction(Function &F) override;
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};
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}
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char LowerInvokeLegacyPass::ID = 0;
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INITIALIZE_PASS(LowerInvokeLegacyPass, "lowerinvoke",
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"Lower invoke and unwind, for unwindless code generators",
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false, false)
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static bool runImpl(Function &F) {
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bool Changed = false;
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for (BasicBlock &BB : F)
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if (InvokeInst *II = dyn_cast<InvokeInst>(BB.getTerminator())) {
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SmallVector<Value *, 16> CallArgs(II->op_begin(), II->op_end() - 3);
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// Insert a normal call instruction...
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CallInst *NewCall =
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CallInst::Create(II->getCalledValue(), CallArgs, "", II);
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NewCall->takeName(II);
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NewCall->setCallingConv(II->getCallingConv());
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NewCall->setAttributes(II->getAttributes());
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NewCall->setDebugLoc(II->getDebugLoc());
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II->replaceAllUsesWith(NewCall);
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// Insert an unconditional branch to the normal destination.
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BranchInst::Create(II->getNormalDest(), II);
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// Remove any PHI node entries from the exception destination.
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II->getUnwindDest()->removePredecessor(&BB);
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// Remove the invoke instruction now.
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BB.getInstList().erase(II);
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++NumInvokes;
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Changed = true;
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}
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return Changed;
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}
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bool LowerInvokeLegacyPass::runOnFunction(Function &F) {
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return runImpl(F);
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}
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namespace llvm {
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char &LowerInvokePassID = LowerInvokeLegacyPass::ID;
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// Public Interface To the LowerInvoke pass.
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FunctionPass *createLowerInvokePass() { return new LowerInvokeLegacyPass(); }
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PreservedAnalyses LowerInvokePass::run(Function &F,
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FunctionAnalysisManager &AM) {
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bool Changed = runImpl(F);
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if (!Changed)
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return PreservedAnalyses::all();
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return PreservedAnalyses::none();
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}
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}
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