SjLjEHPrepare.cpp revision 204792
1198090Srdivacky//===- SjLjEHPass.cpp - Eliminate Invoke & Unwind instructions -----------===// 2198090Srdivacky// 3198090Srdivacky// The LLVM Compiler Infrastructure 4198090Srdivacky// 5198090Srdivacky// This file is distributed under the University of Illinois Open Source 6198090Srdivacky// License. See LICENSE.TXT for details. 7198090Srdivacky// 8198090Srdivacky//===----------------------------------------------------------------------===// 9198090Srdivacky// 10198090Srdivacky// This transformation is designed for use by code generators which use SjLj 11198090Srdivacky// based exception handling. 12198090Srdivacky// 13198090Srdivacky//===----------------------------------------------------------------------===// 14198090Srdivacky 15198090Srdivacky#define DEBUG_TYPE "sjljehprepare" 16198090Srdivacky#include "llvm/Transforms/Scalar.h" 17198090Srdivacky#include "llvm/Constants.h" 18198090Srdivacky#include "llvm/DerivedTypes.h" 19198090Srdivacky#include "llvm/Instructions.h" 20198090Srdivacky#include "llvm/Intrinsics.h" 21198090Srdivacky#include "llvm/LLVMContext.h" 22198090Srdivacky#include "llvm/Module.h" 23198090Srdivacky#include "llvm/Pass.h" 24198090Srdivacky#include "llvm/CodeGen/Passes.h" 25198090Srdivacky#include "llvm/Transforms/Utils/BasicBlockUtils.h" 26198090Srdivacky#include "llvm/Transforms/Utils/Local.h" 27198090Srdivacky#include "llvm/ADT/Statistic.h" 28198090Srdivacky#include "llvm/ADT/SmallVector.h" 29198090Srdivacky#include "llvm/Support/CommandLine.h" 30198090Srdivacky#include "llvm/Support/Debug.h" 31198090Srdivacky#include "llvm/Support/raw_ostream.h" 32198090Srdivacky#include "llvm/Target/TargetLowering.h" 33198090Srdivackyusing namespace llvm; 34198090Srdivacky 35198090SrdivackySTATISTIC(NumInvokes, "Number of invokes replaced"); 36198090SrdivackySTATISTIC(NumUnwinds, "Number of unwinds replaced"); 37198090SrdivackySTATISTIC(NumSpilled, "Number of registers live across unwind edges"); 38198090Srdivacky 39198090Srdivackynamespace { 40198892Srdivacky class SjLjEHPass : public FunctionPass { 41198090Srdivacky 42198090Srdivacky const TargetLowering *TLI; 43198090Srdivacky 44198090Srdivacky const Type *FunctionContextTy; 45198090Srdivacky Constant *RegisterFn; 46198090Srdivacky Constant *UnregisterFn; 47198090Srdivacky Constant *BuiltinSetjmpFn; 48198090Srdivacky Constant *FrameAddrFn; 49198090Srdivacky Constant *LSDAAddrFn; 50198090Srdivacky Value *PersonalityFn; 51198090Srdivacky Constant *SelectorFn; 52198090Srdivacky Constant *ExceptionFn; 53203954Srdivacky Constant *CallSiteFn; 54198090Srdivacky 55198090Srdivacky Value *CallSite; 56198090Srdivacky public: 57198090Srdivacky static char ID; // Pass identification, replacement for typeid 58198090Srdivacky explicit SjLjEHPass(const TargetLowering *tli = NULL) 59198090Srdivacky : FunctionPass(&ID), TLI(tli) { } 60198090Srdivacky bool doInitialization(Module &M); 61198090Srdivacky bool runOnFunction(Function &F); 62198090Srdivacky 63198090Srdivacky virtual void getAnalysisUsage(AnalysisUsage &AU) const { } 64198090Srdivacky const char *getPassName() const { 65198090Srdivacky return "SJLJ Exception Handling preparation"; 66198090Srdivacky } 67198090Srdivacky 68198090Srdivacky private: 69204792Srdivacky void insertCallSiteStore(Instruction *I, int Number, Value *CallSite); 70204792Srdivacky void markInvokeCallSite(InvokeInst *II, int InvokeNo, Value *CallSite, 71198090Srdivacky SwitchInst *CatchSwitch); 72198090Srdivacky void splitLiveRangesLiveAcrossInvokes(SmallVector<InvokeInst*,16> &Invokes); 73198090Srdivacky bool insertSjLjEHSupport(Function &F); 74198090Srdivacky }; 75198090Srdivacky} // end anonymous namespace 76198090Srdivacky 77198090Srdivackychar SjLjEHPass::ID = 0; 78198090Srdivacky 79198090Srdivacky// Public Interface To the SjLjEHPass pass. 80198090SrdivackyFunctionPass *llvm::createSjLjEHPass(const TargetLowering *TLI) { 81198090Srdivacky return new SjLjEHPass(TLI); 82198090Srdivacky} 83198090Srdivacky// doInitialization - Set up decalarations and types needed to process 84198090Srdivacky// exceptions. 85198090Srdivackybool SjLjEHPass::doInitialization(Module &M) { 86198090Srdivacky // Build the function context structure. 87198090Srdivacky // builtin_setjmp uses a five word jbuf 88198090Srdivacky const Type *VoidPtrTy = 89198090Srdivacky Type::getInt8PtrTy(M.getContext()); 90198090Srdivacky const Type *Int32Ty = Type::getInt32Ty(M.getContext()); 91198090Srdivacky FunctionContextTy = 92198090Srdivacky StructType::get(M.getContext(), 93198090Srdivacky VoidPtrTy, // __prev 94198090Srdivacky Int32Ty, // call_site 95198090Srdivacky ArrayType::get(Int32Ty, 4), // __data 96198090Srdivacky VoidPtrTy, // __personality 97198090Srdivacky VoidPtrTy, // __lsda 98198090Srdivacky ArrayType::get(VoidPtrTy, 5), // __jbuf 99198090Srdivacky NULL); 100198090Srdivacky RegisterFn = M.getOrInsertFunction("_Unwind_SjLj_Register", 101198090Srdivacky Type::getVoidTy(M.getContext()), 102198090Srdivacky PointerType::getUnqual(FunctionContextTy), 103198090Srdivacky (Type *)0); 104198090Srdivacky UnregisterFn = 105198090Srdivacky M.getOrInsertFunction("_Unwind_SjLj_Unregister", 106198090Srdivacky Type::getVoidTy(M.getContext()), 107198090Srdivacky PointerType::getUnqual(FunctionContextTy), 108198090Srdivacky (Type *)0); 109198090Srdivacky FrameAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::frameaddress); 110198090Srdivacky BuiltinSetjmpFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_setjmp); 111198090Srdivacky LSDAAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_lsda); 112198090Srdivacky SelectorFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_selector); 113198090Srdivacky ExceptionFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_exception); 114203954Srdivacky CallSiteFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_callsite); 115198090Srdivacky PersonalityFn = 0; 116198090Srdivacky 117198090Srdivacky return true; 118198090Srdivacky} 119198090Srdivacky 120204792Srdivacky/// insertCallSiteStore - Insert a store of the call-site value to the 121204792Srdivacky/// function context 122204792Srdivackyvoid SjLjEHPass::insertCallSiteStore(Instruction *I, int Number, 123204792Srdivacky Value *CallSite) { 124204792Srdivacky ConstantInt *CallSiteNoC = ConstantInt::get(Type::getInt32Ty(I->getContext()), 125204792Srdivacky Number); 126204792Srdivacky // Insert a store of the call-site number 127204792Srdivacky new StoreInst(CallSiteNoC, CallSite, true, I); // volatile 128204792Srdivacky} 129204792Srdivacky 130198090Srdivacky/// markInvokeCallSite - Insert code to mark the call_site for this invoke 131204792Srdivackyvoid SjLjEHPass::markInvokeCallSite(InvokeInst *II, int InvokeNo, 132198090Srdivacky Value *CallSite, 133198090Srdivacky SwitchInst *CatchSwitch) { 134198090Srdivacky ConstantInt *CallSiteNoC= ConstantInt::get(Type::getInt32Ty(II->getContext()), 135204792Srdivacky InvokeNo); 136198090Srdivacky // The runtime comes back to the dispatcher with the call_site - 1 in 137198090Srdivacky // the context. Odd, but there it is. 138198090Srdivacky ConstantInt *SwitchValC = ConstantInt::get(Type::getInt32Ty(II->getContext()), 139198090Srdivacky InvokeNo - 1); 140198090Srdivacky 141198090Srdivacky // If the unwind edge has phi nodes, split the edge. 142198090Srdivacky if (isa<PHINode>(II->getUnwindDest()->begin())) { 143198090Srdivacky SplitCriticalEdge(II, 1, this); 144198090Srdivacky 145198090Srdivacky // If there are any phi nodes left, they must have a single predecessor. 146198090Srdivacky while (PHINode *PN = dyn_cast<PHINode>(II->getUnwindDest()->begin())) { 147198090Srdivacky PN->replaceAllUsesWith(PN->getIncomingValue(0)); 148198090Srdivacky PN->eraseFromParent(); 149198090Srdivacky } 150198090Srdivacky } 151198090Srdivacky 152204792Srdivacky // Insert the store of the call site value 153204792Srdivacky insertCallSiteStore(II, InvokeNo, CallSite); 154204792Srdivacky 155204792Srdivacky // Record the call site value for the back end so it stays associated with 156204792Srdivacky // the invoke. 157203954Srdivacky CallInst::Create(CallSiteFn, CallSiteNoC, "", II); 158198090Srdivacky 159198090Srdivacky // Add a switch case to our unwind block. 160198090Srdivacky CatchSwitch->addCase(SwitchValC, II->getUnwindDest()); 161203954Srdivacky // We still want this to look like an invoke so we emit the LSDA properly, 162203954Srdivacky // so we don't transform the invoke into a call here. 163198090Srdivacky} 164198090Srdivacky 165198090Srdivacky/// MarkBlocksLiveIn - Insert BB and all of its predescessors into LiveBBs until 166198090Srdivacky/// we reach blocks we've already seen. 167198090Srdivackystatic void MarkBlocksLiveIn(BasicBlock *BB, std::set<BasicBlock*> &LiveBBs) { 168198090Srdivacky if (!LiveBBs.insert(BB).second) return; // already been here. 169198090Srdivacky 170198090Srdivacky for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) 171198090Srdivacky MarkBlocksLiveIn(*PI, LiveBBs); 172198090Srdivacky} 173198090Srdivacky 174198090Srdivacky/// splitLiveRangesAcrossInvokes - Each value that is live across an unwind edge 175198090Srdivacky/// we spill into a stack location, guaranteeing that there is nothing live 176198090Srdivacky/// across the unwind edge. This process also splits all critical edges 177198090Srdivacky/// coming out of invoke's. 178198090Srdivackyvoid SjLjEHPass:: 179198090SrdivackysplitLiveRangesLiveAcrossInvokes(SmallVector<InvokeInst*,16> &Invokes) { 180198090Srdivacky // First step, split all critical edges from invoke instructions. 181198090Srdivacky for (unsigned i = 0, e = Invokes.size(); i != e; ++i) { 182198090Srdivacky InvokeInst *II = Invokes[i]; 183198090Srdivacky SplitCriticalEdge(II, 0, this); 184198090Srdivacky SplitCriticalEdge(II, 1, this); 185198090Srdivacky assert(!isa<PHINode>(II->getNormalDest()) && 186198090Srdivacky !isa<PHINode>(II->getUnwindDest()) && 187198090Srdivacky "critical edge splitting left single entry phi nodes?"); 188198090Srdivacky } 189198090Srdivacky 190198090Srdivacky Function *F = Invokes.back()->getParent()->getParent(); 191198090Srdivacky 192198090Srdivacky // To avoid having to handle incoming arguments specially, we lower each arg 193198090Srdivacky // to a copy instruction in the entry block. This ensures that the argument 194198090Srdivacky // value itself cannot be live across the entry block. 195198090Srdivacky BasicBlock::iterator AfterAllocaInsertPt = F->begin()->begin(); 196198090Srdivacky while (isa<AllocaInst>(AfterAllocaInsertPt) && 197198090Srdivacky isa<ConstantInt>(cast<AllocaInst>(AfterAllocaInsertPt)->getArraySize())) 198198090Srdivacky ++AfterAllocaInsertPt; 199198090Srdivacky for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end(); 200198090Srdivacky AI != E; ++AI) { 201198090Srdivacky // This is always a no-op cast because we're casting AI to AI->getType() so 202198090Srdivacky // src and destination types are identical. BitCast is the only possibility. 203198090Srdivacky CastInst *NC = new BitCastInst( 204198090Srdivacky AI, AI->getType(), AI->getName()+".tmp", AfterAllocaInsertPt); 205198090Srdivacky AI->replaceAllUsesWith(NC); 206198090Srdivacky // Normally its is forbidden to replace a CastInst's operand because it 207198090Srdivacky // could cause the opcode to reflect an illegal conversion. However, we're 208198090Srdivacky // replacing it here with the same value it was constructed with to simply 209198090Srdivacky // make NC its user. 210198090Srdivacky NC->setOperand(0, AI); 211198090Srdivacky } 212198090Srdivacky 213198090Srdivacky // Finally, scan the code looking for instructions with bad live ranges. 214198090Srdivacky for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) 215198090Srdivacky for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E; ++II) { 216198090Srdivacky // Ignore obvious cases we don't have to handle. In particular, most 217198090Srdivacky // instructions either have no uses or only have a single use inside the 218198090Srdivacky // current block. Ignore them quickly. 219198090Srdivacky Instruction *Inst = II; 220198090Srdivacky if (Inst->use_empty()) continue; 221198090Srdivacky if (Inst->hasOneUse() && 222198090Srdivacky cast<Instruction>(Inst->use_back())->getParent() == BB && 223198090Srdivacky !isa<PHINode>(Inst->use_back())) continue; 224198090Srdivacky 225198090Srdivacky // If this is an alloca in the entry block, it's not a real register 226198090Srdivacky // value. 227198090Srdivacky if (AllocaInst *AI = dyn_cast<AllocaInst>(Inst)) 228198090Srdivacky if (isa<ConstantInt>(AI->getArraySize()) && BB == F->begin()) 229198090Srdivacky continue; 230198090Srdivacky 231198090Srdivacky // Avoid iterator invalidation by copying users to a temporary vector. 232198090Srdivacky SmallVector<Instruction*,16> Users; 233198090Srdivacky for (Value::use_iterator UI = Inst->use_begin(), E = Inst->use_end(); 234198090Srdivacky UI != E; ++UI) { 235198090Srdivacky Instruction *User = cast<Instruction>(*UI); 236198090Srdivacky if (User->getParent() != BB || isa<PHINode>(User)) 237198090Srdivacky Users.push_back(User); 238198090Srdivacky } 239198090Srdivacky 240198090Srdivacky // Find all of the blocks that this value is live in. 241198090Srdivacky std::set<BasicBlock*> LiveBBs; 242198090Srdivacky LiveBBs.insert(Inst->getParent()); 243198090Srdivacky while (!Users.empty()) { 244198090Srdivacky Instruction *U = Users.back(); 245198090Srdivacky Users.pop_back(); 246198090Srdivacky 247198090Srdivacky if (!isa<PHINode>(U)) { 248198090Srdivacky MarkBlocksLiveIn(U->getParent(), LiveBBs); 249198090Srdivacky } else { 250198090Srdivacky // Uses for a PHI node occur in their predecessor block. 251198090Srdivacky PHINode *PN = cast<PHINode>(U); 252198090Srdivacky for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) 253198090Srdivacky if (PN->getIncomingValue(i) == Inst) 254198090Srdivacky MarkBlocksLiveIn(PN->getIncomingBlock(i), LiveBBs); 255198090Srdivacky } 256198090Srdivacky } 257198090Srdivacky 258198090Srdivacky // Now that we know all of the blocks that this thing is live in, see if 259198090Srdivacky // it includes any of the unwind locations. 260198090Srdivacky bool NeedsSpill = false; 261198090Srdivacky for (unsigned i = 0, e = Invokes.size(); i != e; ++i) { 262198090Srdivacky BasicBlock *UnwindBlock = Invokes[i]->getUnwindDest(); 263198090Srdivacky if (UnwindBlock != BB && LiveBBs.count(UnwindBlock)) { 264198090Srdivacky NeedsSpill = true; 265198090Srdivacky } 266198090Srdivacky } 267198090Srdivacky 268198090Srdivacky // If we decided we need a spill, do it. 269198090Srdivacky if (NeedsSpill) { 270198090Srdivacky ++NumSpilled; 271198090Srdivacky DemoteRegToStack(*Inst, true); 272198090Srdivacky } 273198090Srdivacky } 274198090Srdivacky} 275198090Srdivacky 276198090Srdivackybool SjLjEHPass::insertSjLjEHSupport(Function &F) { 277198090Srdivacky SmallVector<ReturnInst*,16> Returns; 278198090Srdivacky SmallVector<UnwindInst*,16> Unwinds; 279198090Srdivacky SmallVector<InvokeInst*,16> Invokes; 280198090Srdivacky 281198090Srdivacky // Look through the terminators of the basic blocks to find invokes, returns 282204792Srdivacky // and unwinds. 283204792Srdivacky for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) { 284198090Srdivacky if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) { 285198090Srdivacky // Remember all return instructions in case we insert an invoke into this 286198090Srdivacky // function. 287198090Srdivacky Returns.push_back(RI); 288198090Srdivacky } else if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) { 289198090Srdivacky Invokes.push_back(II); 290198090Srdivacky } else if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) { 291198090Srdivacky Unwinds.push_back(UI); 292198090Srdivacky } 293204792Srdivacky } 294198090Srdivacky // If we don't have any invokes or unwinds, there's nothing to do. 295198090Srdivacky if (Unwinds.empty() && Invokes.empty()) return false; 296198090Srdivacky 297198090Srdivacky // Find the eh.selector.* and eh.exception calls. We'll use the first 298198090Srdivacky // eh.selector to determine the right personality function to use. For 299198090Srdivacky // SJLJ, we always use the same personality for the whole function, 300198090Srdivacky // not on a per-selector basis. 301198090Srdivacky // FIXME: That's a bit ugly. Better way? 302198090Srdivacky SmallVector<CallInst*,16> EH_Selectors; 303198090Srdivacky SmallVector<CallInst*,16> EH_Exceptions; 304198090Srdivacky for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) { 305198090Srdivacky for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) { 306198090Srdivacky if (CallInst *CI = dyn_cast<CallInst>(I)) { 307198090Srdivacky if (CI->getCalledFunction() == SelectorFn) { 308198090Srdivacky if (!PersonalityFn) PersonalityFn = CI->getOperand(2); 309198090Srdivacky EH_Selectors.push_back(CI); 310198090Srdivacky } else if (CI->getCalledFunction() == ExceptionFn) { 311198090Srdivacky EH_Exceptions.push_back(CI); 312198090Srdivacky } 313198090Srdivacky } 314198090Srdivacky } 315198090Srdivacky } 316198090Srdivacky // If we don't have any eh.selector calls, we can't determine the personality 317198090Srdivacky // function. Without a personality function, we can't process exceptions. 318198090Srdivacky if (!PersonalityFn) return false; 319198090Srdivacky 320198090Srdivacky NumInvokes += Invokes.size(); 321198090Srdivacky NumUnwinds += Unwinds.size(); 322198090Srdivacky 323198090Srdivacky if (!Invokes.empty()) { 324198090Srdivacky // We have invokes, so we need to add register/unregister calls to get 325198090Srdivacky // this function onto the global unwind stack. 326198090Srdivacky // 327198090Srdivacky // First thing we need to do is scan the whole function for values that are 328198090Srdivacky // live across unwind edges. Each value that is live across an unwind edge 329198090Srdivacky // we spill into a stack location, guaranteeing that there is nothing live 330198090Srdivacky // across the unwind edge. This process also splits all critical edges 331198090Srdivacky // coming out of invoke's. 332198090Srdivacky splitLiveRangesLiveAcrossInvokes(Invokes); 333198090Srdivacky 334198090Srdivacky BasicBlock *EntryBB = F.begin(); 335198090Srdivacky // Create an alloca for the incoming jump buffer ptr and the new jump buffer 336198090Srdivacky // that needs to be restored on all exits from the function. This is an 337198090Srdivacky // alloca because the value needs to be added to the global context list. 338198090Srdivacky unsigned Align = 4; // FIXME: Should be a TLI check? 339198090Srdivacky AllocaInst *FunctionContext = 340198090Srdivacky new AllocaInst(FunctionContextTy, 0, Align, 341198090Srdivacky "fcn_context", F.begin()->begin()); 342198090Srdivacky 343198090Srdivacky Value *Idxs[2]; 344198090Srdivacky const Type *Int32Ty = Type::getInt32Ty(F.getContext()); 345198090Srdivacky Value *Zero = ConstantInt::get(Int32Ty, 0); 346198090Srdivacky // We need to also keep around a reference to the call_site field 347198090Srdivacky Idxs[0] = Zero; 348198090Srdivacky Idxs[1] = ConstantInt::get(Int32Ty, 1); 349198090Srdivacky CallSite = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2, 350198090Srdivacky "call_site", 351198090Srdivacky EntryBB->getTerminator()); 352198090Srdivacky 353198090Srdivacky // The exception selector comes back in context->data[1] 354198090Srdivacky Idxs[1] = ConstantInt::get(Int32Ty, 2); 355198090Srdivacky Value *FCData = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2, 356198090Srdivacky "fc_data", 357198090Srdivacky EntryBB->getTerminator()); 358198090Srdivacky Idxs[1] = ConstantInt::get(Int32Ty, 1); 359198090Srdivacky Value *SelectorAddr = GetElementPtrInst::Create(FCData, Idxs, Idxs+2, 360198090Srdivacky "exc_selector_gep", 361198090Srdivacky EntryBB->getTerminator()); 362198090Srdivacky // The exception value comes back in context->data[0] 363198090Srdivacky Idxs[1] = Zero; 364198090Srdivacky Value *ExceptionAddr = GetElementPtrInst::Create(FCData, Idxs, Idxs+2, 365198090Srdivacky "exception_gep", 366198090Srdivacky EntryBB->getTerminator()); 367198090Srdivacky 368198090Srdivacky // The result of the eh.selector call will be replaced with a 369198090Srdivacky // a reference to the selector value returned in the function 370198090Srdivacky // context. We leave the selector itself so the EH analysis later 371198090Srdivacky // can use it. 372198090Srdivacky for (int i = 0, e = EH_Selectors.size(); i < e; ++i) { 373198090Srdivacky CallInst *I = EH_Selectors[i]; 374198090Srdivacky Value *SelectorVal = new LoadInst(SelectorAddr, "select_val", true, I); 375198090Srdivacky I->replaceAllUsesWith(SelectorVal); 376198090Srdivacky } 377198090Srdivacky // eh.exception calls are replaced with references to the proper 378198090Srdivacky // location in the context. Unlike eh.selector, the eh.exception 379198090Srdivacky // calls are removed entirely. 380198090Srdivacky for (int i = 0, e = EH_Exceptions.size(); i < e; ++i) { 381198090Srdivacky CallInst *I = EH_Exceptions[i]; 382198090Srdivacky // Possible for there to be duplicates, so check to make sure 383198090Srdivacky // the instruction hasn't already been removed. 384198090Srdivacky if (!I->getParent()) continue; 385198090Srdivacky Value *Val = new LoadInst(ExceptionAddr, "exception", true, I); 386198090Srdivacky const Type *Ty = Type::getInt8PtrTy(F.getContext()); 387198090Srdivacky Val = CastInst::Create(Instruction::IntToPtr, Val, Ty, "", I); 388198090Srdivacky 389198090Srdivacky I->replaceAllUsesWith(Val); 390198090Srdivacky I->eraseFromParent(); 391198090Srdivacky } 392198090Srdivacky 393198090Srdivacky // The entry block changes to have the eh.sjlj.setjmp, with a conditional 394198090Srdivacky // branch to a dispatch block for non-zero returns. If we return normally, 395198090Srdivacky // we're not handling an exception and just register the function context 396198090Srdivacky // and continue. 397198090Srdivacky 398198090Srdivacky // Create the dispatch block. The dispatch block is basically a big switch 399198090Srdivacky // statement that goes to all of the invoke landing pads. 400198090Srdivacky BasicBlock *DispatchBlock = 401198090Srdivacky BasicBlock::Create(F.getContext(), "eh.sjlj.setjmp.catch", &F); 402198090Srdivacky 403198090Srdivacky // Insert a load in the Catch block, and a switch on its value. By default, 404198090Srdivacky // we go to a block that just does an unwind (which is the correct action 405198090Srdivacky // for a standard call). 406202375Srdivacky BasicBlock *UnwindBlock = 407202375Srdivacky BasicBlock::Create(F.getContext(), "unwindbb", &F); 408198090Srdivacky Unwinds.push_back(new UnwindInst(F.getContext(), UnwindBlock)); 409198090Srdivacky 410198090Srdivacky Value *DispatchLoad = new LoadInst(CallSite, "invoke.num", true, 411198090Srdivacky DispatchBlock); 412198090Srdivacky SwitchInst *DispatchSwitch = 413202375Srdivacky SwitchInst::Create(DispatchLoad, UnwindBlock, Invokes.size(), 414202375Srdivacky DispatchBlock); 415198090Srdivacky // Split the entry block to insert the conditional branch for the setjmp. 416198090Srdivacky BasicBlock *ContBlock = EntryBB->splitBasicBlock(EntryBB->getTerminator(), 417198090Srdivacky "eh.sjlj.setjmp.cont"); 418198090Srdivacky 419198090Srdivacky // Populate the Function Context 420198090Srdivacky // 1. LSDA address 421198090Srdivacky // 2. Personality function address 422198090Srdivacky // 3. jmpbuf (save FP and call eh.sjlj.setjmp) 423198090Srdivacky 424198090Srdivacky // LSDA address 425198090Srdivacky Idxs[0] = Zero; 426198090Srdivacky Idxs[1] = ConstantInt::get(Int32Ty, 4); 427198090Srdivacky Value *LSDAFieldPtr = 428198090Srdivacky GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2, 429198090Srdivacky "lsda_gep", 430198090Srdivacky EntryBB->getTerminator()); 431198090Srdivacky Value *LSDA = CallInst::Create(LSDAAddrFn, "lsda_addr", 432198090Srdivacky EntryBB->getTerminator()); 433198090Srdivacky new StoreInst(LSDA, LSDAFieldPtr, true, EntryBB->getTerminator()); 434198090Srdivacky 435198090Srdivacky Idxs[1] = ConstantInt::get(Int32Ty, 3); 436198090Srdivacky Value *PersonalityFieldPtr = 437198090Srdivacky GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2, 438198090Srdivacky "lsda_gep", 439198090Srdivacky EntryBB->getTerminator()); 440198090Srdivacky new StoreInst(PersonalityFn, PersonalityFieldPtr, true, 441198090Srdivacky EntryBB->getTerminator()); 442198090Srdivacky 443198090Srdivacky // Save the frame pointer. 444198090Srdivacky Idxs[1] = ConstantInt::get(Int32Ty, 5); 445198090Srdivacky Value *FieldPtr 446198090Srdivacky = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2, 447198090Srdivacky "jbuf_gep", 448198090Srdivacky EntryBB->getTerminator()); 449198090Srdivacky Idxs[1] = ConstantInt::get(Int32Ty, 0); 450198090Srdivacky Value *ElemPtr = 451198090Srdivacky GetElementPtrInst::Create(FieldPtr, Idxs, Idxs+2, "jbuf_fp_gep", 452198090Srdivacky EntryBB->getTerminator()); 453198090Srdivacky 454198090Srdivacky Value *Val = CallInst::Create(FrameAddrFn, 455198090Srdivacky ConstantInt::get(Int32Ty, 0), 456198090Srdivacky "fp", 457198090Srdivacky EntryBB->getTerminator()); 458198090Srdivacky new StoreInst(Val, ElemPtr, true, EntryBB->getTerminator()); 459198090Srdivacky // Call the setjmp instrinsic. It fills in the rest of the jmpbuf 460198090Srdivacky Value *SetjmpArg = 461198090Srdivacky CastInst::Create(Instruction::BitCast, FieldPtr, 462198090Srdivacky Type::getInt8PtrTy(F.getContext()), "", 463198090Srdivacky EntryBB->getTerminator()); 464198090Srdivacky Value *DispatchVal = CallInst::Create(BuiltinSetjmpFn, SetjmpArg, 465198090Srdivacky "dispatch", 466198090Srdivacky EntryBB->getTerminator()); 467198090Srdivacky // check the return value of the setjmp. non-zero goes to dispatcher 468198090Srdivacky Value *IsNormal = new ICmpInst(EntryBB->getTerminator(), 469198090Srdivacky ICmpInst::ICMP_EQ, DispatchVal, Zero, 470198090Srdivacky "notunwind"); 471198090Srdivacky // Nuke the uncond branch. 472198090Srdivacky EntryBB->getTerminator()->eraseFromParent(); 473198090Srdivacky 474198090Srdivacky // Put in a new condbranch in its place. 475198090Srdivacky BranchInst::Create(ContBlock, DispatchBlock, IsNormal, EntryBB); 476198090Srdivacky 477198090Srdivacky // Register the function context and make sure it's known to not throw 478198090Srdivacky CallInst *Register = 479198090Srdivacky CallInst::Create(RegisterFn, FunctionContext, "", 480198090Srdivacky ContBlock->getTerminator()); 481198090Srdivacky Register->setDoesNotThrow(); 482198090Srdivacky 483198090Srdivacky // At this point, we are all set up, update the invoke instructions 484198090Srdivacky // to mark their call_site values, and fill in the dispatch switch 485198090Srdivacky // accordingly. 486198090Srdivacky for (unsigned i = 0, e = Invokes.size(); i != e; ++i) 487198090Srdivacky markInvokeCallSite(Invokes[i], i+1, CallSite, DispatchSwitch); 488198090Srdivacky 489204792Srdivacky // Mark call instructions that aren't nounwind as no-action 490204792Srdivacky // (call_site == -1). Skip the entry block, as prior to then, no function 491204792Srdivacky // context has been created for this function and any unexpected exceptions 492204792Srdivacky // thrown will go directly to the caller's context, which is what we want 493204792Srdivacky // anyway, so no need to do anything here. 494204792Srdivacky for (Function::iterator BB = F.begin(), E = F.end(); ++BB != E;) { 495204792Srdivacky for (BasicBlock::iterator I = BB->begin(), end = BB->end(); I != end; ++I) 496204792Srdivacky if (CallInst *CI = dyn_cast<CallInst>(I)) { 497204792Srdivacky // Ignore calls to the EH builtins (eh.selector, eh.exception) 498204792Srdivacky Constant *Callee = CI->getCalledFunction(); 499204792Srdivacky if (Callee != SelectorFn && Callee != ExceptionFn 500204792Srdivacky && !CI->doesNotThrow()) 501204792Srdivacky insertCallSiteStore(CI, -1, CallSite); 502198090Srdivacky } 503204792Srdivacky } 504198090Srdivacky 505198090Srdivacky // Replace all unwinds with a branch to the unwind handler. 506198090Srdivacky // ??? Should this ever happen with sjlj exceptions? 507198090Srdivacky for (unsigned i = 0, e = Unwinds.size(); i != e; ++i) { 508198090Srdivacky BranchInst::Create(UnwindBlock, Unwinds[i]); 509198090Srdivacky Unwinds[i]->eraseFromParent(); 510198090Srdivacky } 511198090Srdivacky 512198090Srdivacky // Finally, for any returns from this function, if this function contains an 513198090Srdivacky // invoke, add a call to unregister the function context. 514198090Srdivacky for (unsigned i = 0, e = Returns.size(); i != e; ++i) 515198090Srdivacky CallInst::Create(UnregisterFn, FunctionContext, "", Returns[i]); 516198090Srdivacky } 517198090Srdivacky 518198090Srdivacky return true; 519198090Srdivacky} 520198090Srdivacky 521198090Srdivackybool SjLjEHPass::runOnFunction(Function &F) { 522198090Srdivacky bool Res = insertSjLjEHSupport(F); 523198090Srdivacky return Res; 524198090Srdivacky} 525