1 //===- LowerInvoke.cpp - Eliminate Invoke instructions --------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This transformation is designed for use by code generators which do not yet 11 // support stack unwinding. This pass converts 'invoke' instructions to 'call' 12 // instructions, so that any exception-handling 'landingpad' blocks become dead 13 // code (which can be removed by running the '-simplifycfg' pass afterwards). 14 // 15 //===----------------------------------------------------------------------===// 16 17 #include "llvm/Transforms/Scalar.h" 18 #include "llvm/ADT/SmallVector.h" 19 #include "llvm/ADT/Statistic.h" 20 #include "llvm/IR/Instructions.h" 21 #include "llvm/IR/LLVMContext.h" 22 #include "llvm/IR/Module.h" 23 #include "llvm/Pass.h" 24 #include "llvm/Support/CommandLine.h" 25 using namespace llvm; 26 27 #define DEBUG_TYPE "lowerinvoke" 28 29 STATISTIC(NumInvokes, "Number of invokes replaced"); 30 31 namespace { 32 class LowerInvoke : public FunctionPass { 33 public: 34 static char ID; // Pass identification, replacement for typeid 35 explicit LowerInvoke() : FunctionPass(ID) { 36 initializeLowerInvokePass(*PassRegistry::getPassRegistry()); 37 } 38 bool runOnFunction(Function &F) override; 39 }; 40 } 41 42 char LowerInvoke::ID = 0; 43 INITIALIZE_PASS(LowerInvoke, "lowerinvoke", 44 "Lower invoke and unwind, for unwindless code generators", 45 false, false) 46 47 char &llvm::LowerInvokePassID = LowerInvoke::ID; 48 49 // Public Interface To the LowerInvoke pass. 50 FunctionPass *llvm::createLowerInvokePass() { 51 return new LowerInvoke(); 52 } 53 54 bool LowerInvoke::runOnFunction(Function &F) { 55 bool Changed = false; 56 for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) 57 if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) { 58 SmallVector<Value*,16> CallArgs(II->op_begin(), II->op_end() - 3); 59 // Insert a normal call instruction... 60 CallInst *NewCall = CallInst::Create(II->getCalledValue(), 61 CallArgs, "", II); 62 NewCall->takeName(II); 63 NewCall->setCallingConv(II->getCallingConv()); 64 NewCall->setAttributes(II->getAttributes()); 65 NewCall->setDebugLoc(II->getDebugLoc()); 66 II->replaceAllUsesWith(NewCall); 67 68 // Insert an unconditional branch to the normal destination. 69 BranchInst::Create(II->getNormalDest(), II); 70 71 // Remove any PHI node entries from the exception destination. 72 II->getUnwindDest()->removePredecessor(BB); 73 74 // Remove the invoke instruction now. 75 BB->getInstList().erase(II); 76 77 ++NumInvokes; Changed = true; 78 } 79 return Changed; 80 } 81
