13e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner//===- PruneEH.cpp - Pass which deletes unused exception handlers ---------===// 2fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman// 3b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell// The LLVM Compiler Infrastructure 4b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell// 54ee451de366474b9c228b4e5fa573795a715216dChris Lattner// This file is distributed under the University of Illinois Open Source 64ee451de366474b9c228b4e5fa573795a715216dChris Lattner// License. See LICENSE.TXT for details. 7fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman// 8b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell//===----------------------------------------------------------------------===// 93e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner// 103e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner// This file implements a simple interprocedural pass which walks the 1194c22716d60ff5edf6a98a3c67e0faa001be1142Sylvestre Ledru// call-graph, turning invoke instructions into calls, iff the callee cannot 12cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands// throw an exception, and marking functions 'nounwind' if they cannot throw. 13cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands// It implements this as a bottom-up traversal of the call-graph. 143e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner// 153e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner//===----------------------------------------------------------------------===// 163e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner 171e2385b941242f2f96398dc62767420622856149Chris Lattner#include "llvm/Transforms/IPO.h" 18d04a8d4b33ff316ca4cf961e06c9e312eff8e64fChandler Carruth#include "llvm/ADT/SmallPtrSet.h" 19d04a8d4b33ff316ca4cf961e06c9e312eff8e64fChandler Carruth#include "llvm/ADT/SmallVector.h" 20d04a8d4b33ff316ca4cf961e06c9e312eff8e64fChandler Carruth#include "llvm/ADT/Statistic.h" 21ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines#include "llvm/Support/raw_ostream.h" 22d04a8d4b33ff316ca4cf961e06c9e312eff8e64fChandler Carruth#include "llvm/Analysis/CallGraph.h" 233251e81d793a293b78f4914be6093b405c24fc2aChandler Carruth#include "llvm/Analysis/CallGraphSCCPass.h" 24cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar#include "llvm/Analysis/EHPersonalities.h" 2536b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines#include "llvm/IR/CFG.h" 260b8c9a80f20772c3793201ab5b251d3520b9cea3Chandler Carruth#include "llvm/IR/Constants.h" 270b8c9a80f20772c3793201ab5b251d3520b9cea3Chandler Carruth#include "llvm/IR/Function.h" 28cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar#include "llvm/IR/InlineAsm.h" 290b8c9a80f20772c3793201ab5b251d3520b9cea3Chandler Carruth#include "llvm/IR/Instructions.h" 300b8c9a80f20772c3793201ab5b251d3520b9cea3Chandler Carruth#include "llvm/IR/IntrinsicInst.h" 310b8c9a80f20772c3793201ab5b251d3520b9cea3Chandler Carruth#include "llvm/IR/LLVMContext.h" 32f26801b0e6ab958001f796fd42367e93e9feb96eChris Lattner#include <algorithm> 331e2385b941242f2f96398dc62767420622856149Chris Lattnerusing namespace llvm; 34d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 35dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines#define DEBUG_TYPE "prune-eh" 36dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines 3786453c52ba02e743d29c08456e51006500041456Chris LattnerSTATISTIC(NumRemoved, "Number of invokes removed"); 3886453c52ba02e743d29c08456e51006500041456Chris LattnerSTATISTIC(NumUnreach, "Number of noreturn calls optimized"); 393e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner 4086453c52ba02e743d29c08456e51006500041456Chris Lattnernamespace { 416726b6d75a8b679068a58cb954ba97cf9d1690baNick Lewycky struct PruneEH : public CallGraphSCCPass { 42ecd94c804a563f2a86572dcf1d2e81f397e19daaNick Lewycky static char ID; // Pass identification, replacement for typeid 43081c34b725980f995be9080eaec24cd3dfaaf065Owen Anderson PruneEH() : CallGraphSCCPass(ID) { 44081c34b725980f995be9080eaec24cd3dfaaf065Owen Anderson initializePruneEHPass(*PassRegistry::getPassRegistry()); 45081c34b725980f995be9080eaec24cd3dfaaf065Owen Anderson } 46794fd75c67a2cdc128d67342c6d88a504d186896Devang Patel 473e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner // runOnSCC - Analyze the SCC, performing the transformation if possible. 4836b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines bool runOnSCC(CallGraphSCC &SCC) override; 49d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner 50d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner bool SimplifyFunction(Function *F); 51d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner void DeleteBasicBlock(BasicBlock *BB); 523e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner }; 533e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner} 543e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner 55844731a7f1909f55935e3514c9e713a62d67662eDan Gohmanchar PruneEH::ID = 0; 56ae0a7bc68303ce0c8721f0e981ae602601390e68Owen AndersonINITIALIZE_PASS_BEGIN(PruneEH, "prune-eh", 57ae0a7bc68303ce0c8721f0e981ae602601390e68Owen Anderson "Remove unused exception handling info", false, false) 5836b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen HinesINITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass) 59ae0a7bc68303ce0c8721f0e981ae602601390e68Owen AndersonINITIALIZE_PASS_END(PruneEH, "prune-eh", 60ce665bd2e2b581ab0858d1afe359192bac96b868Owen Anderson "Remove unused exception handling info", false, false) 61844731a7f1909f55935e3514c9e713a62d67662eDan Gohman 62c71ca3cdd2d7a08b043ebb717cad0beadaf47450Devang PatelPass *llvm::createPruneEHPass() { return new PruneEH(); } 63f6fb96f5591de185f45ba8cd6ba3a3d98e04a86dChris Lattner 643e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner 652decb22222cac46bb1d9163e7b89d7e5be8ef65fChris Lattnerbool PruneEH::runOnSCC(CallGraphSCC &SCC) { 666cccf03d02936e16319e7cebf7a158643a8b1040Duncan Sands SmallPtrSet<CallGraphNode *, 8> SCCNodes; 6736b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph(); 68d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner bool MadeChange = false; 69d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner 706cccf03d02936e16319e7cebf7a158643a8b1040Duncan Sands // Fill SCCNodes with the elements of the SCC. Used for quickly 716cccf03d02936e16319e7cebf7a158643a8b1040Duncan Sands // looking up whether a given CallGraphNode is in this SCC. 722decb22222cac46bb1d9163e7b89d7e5be8ef65fChris Lattner for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) 732decb22222cac46bb1d9163e7b89d7e5be8ef65fChris Lattner SCCNodes.insert(*I); 746cccf03d02936e16319e7cebf7a158643a8b1040Duncan Sands 75d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner // First pass, scan all of the functions in the SCC, simplifying them 76d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner // according to what we know. 772decb22222cac46bb1d9163e7b89d7e5be8ef65fChris Lattner for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) 782decb22222cac46bb1d9163e7b89d7e5be8ef65fChris Lattner if (Function *F = (*I)->getFunction()) 79d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner MadeChange |= SimplifyFunction(F); 803e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner 81d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner // Next, check to see if any callees might throw or if there are any external 823e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner // functions in this SCC: if so, we cannot prune any functions in this SCC. 836796629611a07bdc9d6bb79ca1cf6cae78325411Dale Johannesen // Definitions that are weak and not declared non-throwing might be 846796629611a07bdc9d6bb79ca1cf6cae78325411Dale Johannesen // overridden at linktime with something that throws, so assume that. 85ee5457cbe88b7f691f774de8515d9a94226d1b00Chris Lattner // If this SCC includes the unwind instruction, we KNOW it throws, so 863e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner // obviously the SCC might throw. 873e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner // 88d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner bool SCCMightUnwind = false, SCCMightReturn = false; 892decb22222cac46bb1d9163e7b89d7e5be8ef65fChris Lattner for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); 902decb22222cac46bb1d9163e7b89d7e5be8ef65fChris Lattner (!SCCMightUnwind || !SCCMightReturn) && I != E; ++I) { 912decb22222cac46bb1d9163e7b89d7e5be8ef65fChris Lattner Function *F = (*I)->getFunction(); 92dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines if (!F) { 93bc9fa589efdfba8c86a8dee4f8e92b79025a7419Chris Lattner SCCMightUnwind = true; 94d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner SCCMightReturn = true; 955df3186f598163258fabf3448d9372843804d1abDuncan Sands } else if (F->isDeclaration() || F->mayBeOverridden()) { 962b0e8990ab33ec2dad21286d3ce01dbb4bbe63c1Duncan Sands SCCMightUnwind |= !F->doesNotThrow(); 972b0e8990ab33ec2dad21286d3ce01dbb4bbe63c1Duncan Sands SCCMightReturn |= !F->doesNotReturn(); 98d08ddd3300d5244012c1765d34b21cc9e11a80adChris Lattner } else { 992b0e8990ab33ec2dad21286d3ce01dbb4bbe63c1Duncan Sands bool CheckUnwind = !SCCMightUnwind && !F->doesNotThrow(); 1002b0e8990ab33ec2dad21286d3ce01dbb4bbe63c1Duncan Sands bool CheckReturn = !SCCMightReturn && !F->doesNotReturn(); 101cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar // Determine if we should scan for InlineAsm in a naked function as it 102cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar // is the only way to return without a ReturnInst. Only do this for 103cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar // no-inline functions as functions which may be inlined cannot 104cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar // meaningfully return via assembly. 105cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar bool CheckReturnViaAsm = CheckReturn && 106cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar F->hasFnAttribute(Attribute::Naked) && 107cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar F->hasFnAttribute(Attribute::NoInline); 108cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands 109cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands if (!CheckUnwind && !CheckReturn) 110cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands continue; 111d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner 112cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar for (const BasicBlock &BB : *F) { 113cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar const TerminatorInst *TI = BB.getTerminator(); 114cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar if (CheckUnwind && TI->mayThrow()) { 115bc9fa589efdfba8c86a8dee4f8e92b79025a7419Chris Lattner SCCMightUnwind = true; 116cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar } else if (CheckReturn && isa<ReturnInst>(TI)) { 117d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner SCCMightReturn = true; 118d08ddd3300d5244012c1765d34b21cc9e11a80adChris Lattner } 119e0def04e430d741daa48f69b05cfe132adb6db11Chris Lattner 120cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar for (const Instruction &I : BB) { 121cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar if ((!CheckUnwind || SCCMightUnwind) && 122cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar (!CheckReturnViaAsm || SCCMightReturn)) 123cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar break; 124cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar 125cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar // Check to see if this function performs an unwind or calls an 126cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar // unwinding function. 127cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar if (CheckUnwind && !SCCMightUnwind && I.mayThrow()) { 128cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar bool InstMightUnwind = true; 129cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar if (const auto *CI = dyn_cast<CallInst>(&I)) { 130cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar if (Function *Callee = CI->getCalledFunction()) { 131d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner CallGraphNode *CalleeNode = CG[Callee]; 132cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar // If the callee is outside our current SCC then we may throw 133cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar // because it might. If it is inside, do nothing. 134cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar if (SCCNodes.count(CalleeNode) > 0) 135cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar InstMightUnwind = false; 136e0def04e430d741daa48f69b05cfe132adb6db11Chris Lattner } 137e0def04e430d741daa48f69b05cfe132adb6db11Chris Lattner } 138cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar SCCMightUnwind |= InstMightUnwind; 139cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar } 140cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar if (CheckReturnViaAsm && !SCCMightReturn) 141cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar if (auto ICS = ImmutableCallSite(&I)) 142cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar if (const auto *IA = dyn_cast<InlineAsm>(ICS.getCalledValue())) 143cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar if (IA->hasSideEffects()) 144cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar SCCMightReturn = true; 145cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar } 146cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar 147cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar if (SCCMightUnwind && SCCMightReturn) 148cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar break; 149ad9b5f31eaa739940c9ec540cc231afb99343304Chris Lattner } 150d08ddd3300d5244012c1765d34b21cc9e11a80adChris Lattner } 151d08ddd3300d5244012c1765d34b21cc9e11a80adChris Lattner } 1523e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner 153d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner // If the SCC doesn't unwind or doesn't throw, note this fact. 154cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands if (!SCCMightUnwind || !SCCMightReturn) 1552decb22222cac46bb1d9163e7b89d7e5be8ef65fChris Lattner for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) { 1562decb22222cac46bb1d9163e7b89d7e5be8ef65fChris Lattner Function *F = (*I)->getFunction(); 1571750632ee13c51e6191c513b163c5f41e0dab4ebBenjamin Kramer 158cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar if (!SCCMightUnwind && !F->hasFnAttribute(Attribute::NoUnwind)) { 159cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar F->addFnAttr(Attribute::NoUnwind); 160cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar MadeChange = true; 161cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar } 162cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar 163cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar if (!SCCMightReturn && !F->hasFnAttribute(Attribute::NoReturn)) { 164cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar F->addFnAttr(Attribute::NoReturn); 165cae62e34984e413414304eab959797ec5c2cbf32Duncan Sands MadeChange = true; 166cae62e34984e413414304eab959797ec5c2cbf32Duncan Sands } 167cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands } 1683e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner 1692decb22222cac46bb1d9163e7b89d7e5be8ef65fChris Lattner for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) { 1703e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner // Convert any invoke instructions to non-throwing functions in this node 1713e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner // into call instructions with a branch. This makes the exception blocks 1723e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner // dead. 1732decb22222cac46bb1d9163e7b89d7e5be8ef65fChris Lattner if (Function *F = (*I)->getFunction()) 174d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner MadeChange |= SimplifyFunction(F); 1753e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner } 1763e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner 177fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman return MadeChange; 1783e64b2e1a44b0bef896d645e9b293ab84dc16ab8Chris Lattner} 179d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 180d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner 181d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner// SimplifyFunction - Given information about callees, simplify the specified 182d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner// function if we have invokes to non-unwinding functions or code after calls to 183d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner// no-return functions. 184d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattnerbool PruneEH::SimplifyFunction(Function *F) { 185d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner bool MadeChange = false; 186d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) { 187d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) 188cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar if (II->doesNotThrow() && canSimplifyInvokeNoUnwind(F)) { 189cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar SmallVector<Value*, 8> Args(II->arg_begin(), II->arg_end()); 190cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar SmallVector<OperandBundleDef, 1> OpBundles; 191cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar II->getOperandBundlesAsDefs(OpBundles); 192cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar 193cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands // Insert a call instruction before the invoke. 194cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar CallInst *Call = CallInst::Create(II->getCalledValue(), Args, OpBundles, 195cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar "", II); 196cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands Call->takeName(II); 197cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands Call->setCallingConv(II->getCallingConv()); 1980598866c052147c31b808391f58434ce3dbfb838Devang Patel Call->setAttributes(II->getAttributes()); 19965a2f77b0e155f7f1b0a31b0bc9f683b441bc8e2Devang Patel Call->setDebugLoc(II->getDebugLoc()); 200cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands 201cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands // Anything that used the value produced by the invoke instruction 202a541b0fde2ab6b8b037edf113d42da41a2c5aae9Chris Lattner // now uses the value produced by the call instruction. Note that we 203a541b0fde2ab6b8b037edf113d42da41a2c5aae9Chris Lattner // do this even for void functions and calls with no uses so that the 204a541b0fde2ab6b8b037edf113d42da41a2c5aae9Chris Lattner // callgraph edge is updated. 205cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands II->replaceAllUsesWith(Call); 206cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands BasicBlock *UnwindBlock = II->getUnwindDest(); 207cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands UnwindBlock->removePredecessor(II->getParent()); 208cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands 209cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands // Insert a branch to the normal destination right before the 210cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands // invoke. 211051a950000e21935165db56695e35bade668193bGabor Greif BranchInst::Create(II->getNormalDest(), II); 212cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands 213cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands // Finally, delete the invoke instruction! 214cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands BB->getInstList().pop_back(); 215cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands 216cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands // If the unwind block is now dead, nuke it. 217ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines if (pred_empty(UnwindBlock)) 218cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands DeleteBasicBlock(UnwindBlock); // Delete the new BB. 219cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands 220cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands ++NumRemoved; 221cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands MadeChange = true; 222f336983bbcdc21fba7dcc02f4f6cfc06341b1e6dNick Lewycky } 223d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner 224cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) 225280a6e607d8eb7401749a92db624a82de47da777Nick Lewycky if (CallInst *CI = dyn_cast<CallInst>(I++)) 2262b0e8990ab33ec2dad21286d3ce01dbb4bbe63c1Duncan Sands if (CI->doesNotReturn() && !isa<UnreachableInst>(I)) { 227cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands // This call calls a function that cannot return. Insert an 228cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands // unreachable instruction after it and simplify the code. Do this 229cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands // by splitting the BB, adding the unreachable, then deleting the 230cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands // new BB. 231cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands BasicBlock *New = BB->splitBasicBlock(I); 232cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands 233cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands // Remove the uncond branch and add an unreachable. 234cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands BB->getInstList().pop_back(); 235cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar new UnreachableInst(BB->getContext(), &*BB); 23600b16889ab461b7ecef1c91ade101186b7f1fce2Jeff Cohen 237cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands DeleteBasicBlock(New); // Delete the new BB. 238d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner MadeChange = true; 239cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands ++NumUnreach; 240cbb8badce8838ece47cb806a0399c77d76a7e11bDuncan Sands break; 2413c4a26226f30f2e9a022d155586e660af38aba1fNick Lewycky } 242d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner } 243280a6e607d8eb7401749a92db624a82de47da777Nick Lewycky 244d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner return MadeChange; 245d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner} 246d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner 247d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner/// DeleteBasicBlock - remove the specified basic block from the program, 248d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner/// updating the callgraph to reflect any now-obsolete edges due to calls that 249d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner/// exist in the BB. 250d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattnervoid PruneEH::DeleteBasicBlock(BasicBlock *BB) { 251ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines assert(pred_empty(BB) && "BB is not dead!"); 25236b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph(); 253d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner 254d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner CallGraphNode *CGN = CG[BB->getParent()]; 255d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner for (BasicBlock::iterator I = BB->end(), E = BB->begin(); I != E; ) { 256d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner --I; 2571f67ce4aa3f65619f54c8a3072539da5b0022841Dale Johannesen if (CallInst *CI = dyn_cast<CallInst>(I)) { 258ca5bec22e0e04d0712f5ac78fc6aeceabcf80955John McCall if (!isa<IntrinsicInst>(I)) 2591f67ce4aa3f65619f54c8a3072539da5b0022841Dale Johannesen CGN->removeCallEdgeFor(CI); 2601f67ce4aa3f65619f54c8a3072539da5b0022841Dale Johannesen } else if (InvokeInst *II = dyn_cast<InvokeInst>(I)) 261d7b9851c4e634ed3599b1a4c70b1c76c90a11686Duncan Sands CGN->removeCallEdgeFor(II); 262d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner if (!I->use_empty()) 2639e9a0d5fc26878e51a58a8b57900fcbf952c2691Owen Anderson I->replaceAllUsesWith(UndefValue::get(I->getType())); 264d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner } 265d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner 266d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner // Get the list of successors of this block. 267d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner std::vector<BasicBlock*> Succs(succ_begin(BB), succ_end(BB)); 268d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner 269d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner for (unsigned i = 0, e = Succs.size(); i != e; ++i) 270d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner Succs[i]->removePredecessor(BB); 27100b16889ab461b7ecef1c91ade101186b7f1fce2Jeff Cohen 272d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner BB->eraseFromParent(); 273d651f441ae4c5a9e2c77a9a38604f83d0d4261eaChris Lattner} 274