SjLjEHPrepare.cpp revision 8b818d7e98309125c6058c4ea72a7dc73b031db2
18b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach//===- SjLjEHPass.cpp - Eliminate Invoke & Unwind instructions -----------===// 28b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// 38b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// The LLVM Compiler Infrastructure 48b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// 58b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// This file is distributed under the University of Illinois Open Source 68b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// License. See LICENSE.TXT for details. 78b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// 88b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach//===----------------------------------------------------------------------===// 98b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// 108b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// This transformation is designed for use by code generators which use SjLj 118b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// based exception handling. 128b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// 138b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach//===----------------------------------------------------------------------===// 148b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 158b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#define DEBUG_TYPE "sjljehprepare" 168b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/Transforms/Scalar.h" 178b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/Constants.h" 188b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/DerivedTypes.h" 198b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/Instructions.h" 208b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/Intrinsics.h" 218b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/LLVMContext.h" 228b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/Module.h" 238b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/Pass.h" 248b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/CodeGen/Passes.h" 258b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/Transforms/Utils/BasicBlockUtils.h" 268b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/Transforms/Utils/Local.h" 278b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/ADT/Statistic.h" 288b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/Support/CommandLine.h" 298b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/Support/Compiler.h" 308b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/Support/Debug.h" 318b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/Support/raw_ostream.h" 328b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include "llvm/Target/TargetLowering.h" 338b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach#include <set> 348b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbachusing namespace llvm; 358b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 368b818d7e98309125c6058c4ea72a7dc73b031db2Jim GrosbachSTATISTIC(NumInvokes, "Number of invokes replaced"); 378b818d7e98309125c6058c4ea72a7dc73b031db2Jim GrosbachSTATISTIC(NumUnwinds, "Number of unwinds replaced"); 388b818d7e98309125c6058c4ea72a7dc73b031db2Jim GrosbachSTATISTIC(NumSpilled, "Number of registers live across unwind edges"); 398b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 408b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbachnamespace { 418b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach class VISIBILITY_HIDDEN SjLjEHPass : public FunctionPass { 428b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 438b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach const TargetLowering *TLI; 448b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 458b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach const Type *FunctionContextTy; 468b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Constant *RegisterFn; 478b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Constant *UnregisterFn; 488b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Constant *ResumeFn; 498b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Constant *BuiltinSetjmpFn; 508b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Constant *FrameAddrFn; 518b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Constant *LSDAAddrFn; 528b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *PersonalityFn; 538b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Constant *Selector32Fn; 548b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Constant *Selector64Fn; 558b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Constant *ExceptionFn; 568b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 578b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *CallSite; 588b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach public: 598b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach static char ID; // Pass identification, replacement for typeid 608b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach explicit SjLjEHPass(const TargetLowering *tli = NULL) 618b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach : FunctionPass(&ID), TLI(tli) { } 628b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach bool doInitialization(Module &M); 638b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach bool runOnFunction(Function &F); 648b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 658b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach virtual void getAnalysisUsage(AnalysisUsage &AU) const { } 668b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach const char *getPassName() const { 678b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach return "SJLJ Exception Handling preparation"; 688b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 698b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 708b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach private: 718b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach void markInvokeCallSite(InvokeInst *II, unsigned InvokeNo, 728b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *CallSite, 738b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach SwitchInst *CatchSwitch); 748b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach void splitLiveRangesLiveAcrossInvokes(std::vector<InvokeInst*> &Invokes); 758b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach bool insertSjLjEHSupport(Function &F); 768b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach }; 778b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach} // end anonymous namespace 788b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 798b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbachchar SjLjEHPass::ID = 0; 808b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 818b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// Public Interface To the SjLjEHPass pass. 828b818d7e98309125c6058c4ea72a7dc73b031db2Jim GrosbachFunctionPass *llvm::createSjLjEHPass(const TargetLowering *TLI) { 838b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach return new SjLjEHPass(TLI); 848b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach} 858b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// doInitialization - Make sure that there is a prototype for abort in the 868b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// current module. 878b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbachbool SjLjEHPass::doInitialization(Module &M) { 888b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Build the function context structure. 898b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // builtin_setjmp uses a five word jbuf 908b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach const Type *VoidPtrTy = 918b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach PointerType::getUnqual(Type::getInt8Ty(M.getContext())); 928b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach const Type *Int32Ty = Type::getInt32Ty(M.getContext()); 938b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach FunctionContextTy = 948b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach StructType::get(M.getContext(), 958b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach VoidPtrTy, // __prev 968b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Int32Ty, // call_site 978b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach ArrayType::get(Int32Ty, 4), // __data 988b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach VoidPtrTy, // __personality 998b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach VoidPtrTy, // __lsda 1008b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach ArrayType::get(VoidPtrTy, 5), // __jbuf 1018b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach NULL); 1028b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach RegisterFn = M.getOrInsertFunction("_Unwind_SjLj_Register", 1038b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Type::getVoidTy(M.getContext()), 1048b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach PointerType::getUnqual(FunctionContextTy), 1058b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach (Type *)0); 1068b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach UnregisterFn = 1078b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach M.getOrInsertFunction("_Unwind_SjLj_Unregister", 1088b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Type::getVoidTy(M.getContext()), 1098b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach PointerType::getUnqual(FunctionContextTy), 1108b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach (Type *)0); 1118b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach ResumeFn = 1128b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach M.getOrInsertFunction("_Unwind_SjLj_Resume", 1138b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Type::getVoidTy(M.getContext()), 1148b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach VoidPtrTy, 1158b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach (Type *)0); 1168b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach FrameAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::frameaddress); 1178b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach BuiltinSetjmpFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_setjmp); 1188b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach LSDAAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_lsda); 1198b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Selector32Fn = Intrinsic::getDeclaration(&M, Intrinsic::eh_selector_i32); 1208b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Selector64Fn = Intrinsic::getDeclaration(&M, Intrinsic::eh_selector_i64); 1218b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach ExceptionFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_exception); 1228b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 1238b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach return true; 1248b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach} 1258b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 1268b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach/// markInvokeCallSite - Insert code to mark the call_site for this invoke 1278b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbachvoid SjLjEHPass::markInvokeCallSite(InvokeInst *II, unsigned InvokeNo, 1288b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *CallSite, 1298b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach SwitchInst *CatchSwitch) { 1308b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach ConstantInt *CallSiteNoC= ConstantInt::get(Type::getInt32Ty(II->getContext()), 1318b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach InvokeNo); 1328b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // The runtime comes back to the dispatcher with the call_site - 1 in 1338b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // the context. Odd, but there it is. 1348b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach ConstantInt *SwitchValC = ConstantInt::get(Type::getInt32Ty(II->getContext()), 1358b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach InvokeNo - 1); 1368b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 1378b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // If the unwind edge has phi nodes, split the edge. 1388b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (isa<PHINode>(II->getUnwindDest()->begin())) { 1398b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach SplitCriticalEdge(II, 1, this); 1408b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 1418b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // If there are any phi nodes left, they must have a single predecessor. 1428b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach while (PHINode *PN = dyn_cast<PHINode>(II->getUnwindDest()->begin())) { 1438b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach PN->replaceAllUsesWith(PN->getIncomingValue(0)); 1448b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach PN->eraseFromParent(); 1458b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 1468b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 1478b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 1488b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Insert a store of the invoke num before the invoke and store zero into the 1498b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // location afterward. 1508b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach new StoreInst(CallSiteNoC, CallSite, true, II); // volatile 1518b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 1528b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Add a switch case to our unwind block. 1538b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach CatchSwitch->addCase(SwitchValC, II->getUnwindDest()); 1548b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // We still want this to look like an invoke so we emit the LSDA properly 1558b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // FIXME: ??? Or will this cause strangeness with mis-matched IDs like 1568b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // when it was in the front end? 1578b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach} 1588b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 1598b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach/// MarkBlocksLiveIn - Insert BB and all of its predescessors into LiveBBs until 1608b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach/// we reach blocks we've already seen. 1618b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbachstatic void MarkBlocksLiveIn(BasicBlock *BB, std::set<BasicBlock*> &LiveBBs) { 1628b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (!LiveBBs.insert(BB).second) return; // already been here. 1638b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 1648b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) 1658b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach MarkBlocksLiveIn(*PI, LiveBBs); 1668b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach} 1678b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 1688b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// live across unwind edges. Each value that is live across an unwind edge 1698b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// we spill into a stack location, guaranteeing that there is nothing live 1708b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// across the unwind edge. This process also splits all critical edges 1718b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// coming out of invoke's. 1728b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbachvoid SjLjEHPass:: 1738b818d7e98309125c6058c4ea72a7dc73b031db2Jim GrosbachsplitLiveRangesLiveAcrossInvokes(std::vector<InvokeInst*> &Invokes) { 1748b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // First step, split all critical edges from invoke instructions. 1758b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (unsigned i = 0, e = Invokes.size(); i != e; ++i) { 1768b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach InvokeInst *II = Invokes[i]; 1778b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach SplitCriticalEdge(II, 0, this); 1788b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach SplitCriticalEdge(II, 1, this); 1798b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach assert(!isa<PHINode>(II->getNormalDest()) && 1808b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach !isa<PHINode>(II->getUnwindDest()) && 1818b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach "critical edge splitting left single entry phi nodes?"); 1828b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 1838b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 1848b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Function *F = Invokes.back()->getParent()->getParent(); 1858b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 1868b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // To avoid having to handle incoming arguments specially, we lower each arg 1878b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // to a copy instruction in the entry block. This ensures that the argument 1888b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // value itself cannot be live across the entry block. 1898b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach BasicBlock::iterator AfterAllocaInsertPt = F->begin()->begin(); 1908b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach while (isa<AllocaInst>(AfterAllocaInsertPt) && 1918b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach isa<ConstantInt>(cast<AllocaInst>(AfterAllocaInsertPt)->getArraySize())) 1928b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach ++AfterAllocaInsertPt; 1938b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end(); 1948b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach AI != E; ++AI) { 1958b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // This is always a no-op cast because we're casting AI to AI->getType() so 1968b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // src and destination types are identical. BitCast is the only possibility. 1978b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach CastInst *NC = new BitCastInst( 1988b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach AI, AI->getType(), AI->getName()+".tmp", AfterAllocaInsertPt); 1998b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach AI->replaceAllUsesWith(NC); 2008b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Normally its is forbidden to replace a CastInst's operand because it 2018b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // could cause the opcode to reflect an illegal conversion. However, we're 2028b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // replacing it here with the same value it was constructed with to simply 2038b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // make NC its user. 2048b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach NC->setOperand(0, AI); 2058b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 2068b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 2078b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Finally, scan the code looking for instructions with bad live ranges. 2088b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) 2098b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E; ++II) { 2108b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Ignore obvious cases we don't have to handle. In particular, most 2118b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // instructions either have no uses or only have a single use inside the 2128b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // current block. Ignore them quickly. 2138b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Instruction *Inst = II; 2148b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (Inst->use_empty()) continue; 2158b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (Inst->hasOneUse() && 2168b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach cast<Instruction>(Inst->use_back())->getParent() == BB && 2178b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach !isa<PHINode>(Inst->use_back())) continue; 2188b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 2198b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // If this is an alloca in the entry block, it's not a real register 2208b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // value. 2218b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (AllocaInst *AI = dyn_cast<AllocaInst>(Inst)) 2228b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (isa<ConstantInt>(AI->getArraySize()) && BB == F->begin()) 2238b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach continue; 2248b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 2258b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Avoid iterator invalidation by copying users to a temporary vector. 2268b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach std::vector<Instruction*> Users; 2278b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (Value::use_iterator UI = Inst->use_begin(), E = Inst->use_end(); 2288b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach UI != E; ++UI) { 2298b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Instruction *User = cast<Instruction>(*UI); 2308b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (User->getParent() != BB || isa<PHINode>(User)) 2318b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Users.push_back(User); 2328b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 2338b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 2348b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Scan all of the uses and see if the live range is live across an unwind 2358b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // edge. If we find a use live across an invoke edge, create an alloca 2368b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // and spill the value. 2378b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach std::set<InvokeInst*> InvokesWithStoreInserted; 2388b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 2398b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Find all of the blocks that this value is live in. 2408b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach std::set<BasicBlock*> LiveBBs; 2418b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach LiveBBs.insert(Inst->getParent()); 2428b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach while (!Users.empty()) { 2438b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Instruction *U = Users.back(); 2448b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Users.pop_back(); 2458b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 2468b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (!isa<PHINode>(U)) { 2478b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach MarkBlocksLiveIn(U->getParent(), LiveBBs); 2488b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } else { 2498b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Uses for a PHI node occur in their predecessor block. 2508b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach PHINode *PN = cast<PHINode>(U); 2518b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) 2528b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (PN->getIncomingValue(i) == Inst) 2538b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach MarkBlocksLiveIn(PN->getIncomingBlock(i), LiveBBs); 2548b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 2558b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 2568b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 2578b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Now that we know all of the blocks that this thing is live in, see if 2588b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // it includes any of the unwind locations. 2598b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach bool NeedsSpill = false; 2608b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (unsigned i = 0, e = Invokes.size(); i != e; ++i) { 2618b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach BasicBlock *UnwindBlock = Invokes[i]->getUnwindDest(); 2628b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (UnwindBlock != BB && LiveBBs.count(UnwindBlock)) { 2638b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach NeedsSpill = true; 2648b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 2658b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 2668b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 2678b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // If we decided we need a spill, do it. 2688b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (NeedsSpill) { 2698b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach ++NumSpilled; 2708b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach DemoteRegToStack(*Inst, true); 2718b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 2728b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 2738b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach} 2748b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 2758b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbachbool SjLjEHPass::insertSjLjEHSupport(Function &F) { 2768b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach std::vector<ReturnInst*> Returns; 2778b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach std::vector<UnwindInst*> Unwinds; 2788b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach std::vector<InvokeInst*> Invokes; 2798b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 2808b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Look through the terminators of the basic blocks to find invokes, returns 2818b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // and unwinds 2828b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) 2838b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) { 2848b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Remember all return instructions in case we insert an invoke into this 2858b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // function. 2868b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Returns.push_back(RI); 2878b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } else if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) { 2888b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Invokes.push_back(II); 2898b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } else if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) { 2908b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Unwinds.push_back(UI); 2918b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 2928b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // If we don't have any invokes or unwinds, there's nothing to do. 2938b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (Unwinds.empty() && Invokes.empty()) return false; 2948b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 2958b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach NumInvokes += Invokes.size(); 2968b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach NumUnwinds += Unwinds.size(); 2978b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 2988b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 2998b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (!Invokes.empty()) { 3008b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // We have invokes, so we need to add register/unregister calls to get 3018b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // this function onto the global unwind stack. 3028b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // 3038b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // First thing we need to do is scan the whole function for values that are 3048b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // live across unwind edges. Each value that is live across an unwind edge 3058b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // we spill into a stack location, guaranteeing that there is nothing live 3068b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // across the unwind edge. This process also splits all critical edges 3078b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // coming out of invoke's. 3088b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach splitLiveRangesLiveAcrossInvokes(Invokes); 3098b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 3108b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach BasicBlock *EntryBB = F.begin(); 3118b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Create an alloca for the incoming jump buffer ptr and the new jump buffer 3128b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // that needs to be restored on all exits from the function. This is an 3138b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // alloca because the value needs to be added to the global context list. 3148b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach unsigned Align = 4; // FIXME: Should be a TLI check? 3158b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach AllocaInst *FunctionContext = 3168b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach new AllocaInst(FunctionContextTy, 0, Align, 3178b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach "fcn_context", F.begin()->begin()); 3188b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 3198b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *Idxs[2]; 3208b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach const Type *Int32Ty = Type::getInt32Ty(F.getContext()); 3218b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *Zero = ConstantInt::get(Int32Ty, 0); 3228b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // We need to also keep around a reference to the call_site field 3238b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Idxs[0] = Zero; 3248b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Idxs[1] = ConstantInt::get(Int32Ty, 1); 3258b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach CallSite = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2, 3268b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach "call_site", 3278b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach EntryBB->getTerminator()); 3288b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 3298b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // The exception selector comes back in context->data[1] 3308b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Idxs[1] = ConstantInt::get(Int32Ty, 2); 3318b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *FCData = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2, 3328b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach "fc_data", 3338b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach EntryBB->getTerminator()); 3348b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Idxs[1] = ConstantInt::get(Int32Ty, 1); 3358b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *SelectorAddr = GetElementPtrInst::Create(FCData, Idxs, Idxs+2, 3368b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach "exc_selector_gep", 3378b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach EntryBB->getTerminator()); 3388b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // The exception value comes back in context->data[0] 3398b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Idxs[1] = Zero; 3408b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *ExceptionAddr = GetElementPtrInst::Create(FCData, Idxs, Idxs+2, 3418b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach "exception_gep", 3428b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach EntryBB->getTerminator()); 3438b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 3448b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Find the eh.selector.* and eh.exception calls. We'll use the first 3458b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // ex.selector to determine the right personality function to use. For 3468b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // SJLJ, we always use the same personality for the whole function, 3478b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // not on a per-selector basis. 3488b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // FIXME: That's a bit ugly. Better way? 3498b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach std::vector<CallInst*> EH_Selectors; 3508b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach std::vector<CallInst*> EH_Exceptions; 3518b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) { 3528b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // for (unsigned i = 0, e = Invokes.size(); i != e; ++i) { 3538b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach// BasicBlock *Pad = Invokes[0]->getUnwindDest(); 3548b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) { 3558b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (CallInst *CI = dyn_cast<CallInst>(I)) { 3568b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (CI->getCalledFunction() == Selector32Fn || 3578b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach CI->getCalledFunction() == Selector64Fn) { 3588b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (!PersonalityFn) PersonalityFn = CI->getOperand(2); 3598b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach EH_Selectors.push_back(CI); 3608b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } else if (CI->getCalledFunction() == ExceptionFn) { 3618b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach EH_Exceptions.push_back(CI); 3628b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 3638b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 3648b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 3658b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 3668b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // The result of the eh.selector call will be replaced with a 3678b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // a reference to the selector value returned in the function 3688b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // context. We leave the selector itself so the EH analysis later 3698b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // can use it. 3708b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (int i = 0, e = EH_Selectors.size(); i < e; ++i) { 3718b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach CallInst *I = EH_Selectors[i]; 3728b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *SelectorVal = new LoadInst(SelectorAddr, "select_val", true, I); 3738b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach I->replaceAllUsesWith(SelectorVal); 3748b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 3758b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // eh.exception calls are replaced with references to the proper 3768b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // location in the context. Unlike eh.selector, the eh.exception 3778b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // calls are removed entirely. 3788b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (int i = 0, e = EH_Exceptions.size(); i < e; ++i) { 3798b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach CallInst *I = EH_Exceptions[i]; 3808b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Possible for there to be duplicates, so check to make sure 3818b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // the instruction hasn't already been removed. 3828b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (!I->getParent()) continue; 3838b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *Val = new LoadInst(ExceptionAddr, "exception", true, I); 3848b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Val = CastInst::Create(Instruction::IntToPtr, Val, 3858b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach PointerType::getUnqual(Type::getInt8Ty(F.getContext())), 3868b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach "", I); 3878b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 3888b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach I->replaceAllUsesWith(Val); 3898b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach I->eraseFromParent(); 3908b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 3918b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 3928b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 3938b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 3948b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 3958b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // The entry block changes to have the eh.sjlj.setjmp, with a conditional 3968b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // branch to a dispatch block for non-zero returns. If we return normally, 3978b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // we're not handling an exception and just register the function context 3988b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // and continue. 3998b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 4008b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Create the dispatch block. The dispatch block is basically a big switch 4018b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // statement that goes to all of the invoke landing pads. 4028b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach BasicBlock *DispatchBlock = 4038b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach BasicBlock::Create(F.getContext(), "eh.sjlj.setjmp.catch", &F); 4048b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 4058b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Insert a load in the Catch block, and a switch on its value. By default, 4068b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // we go to a block that just does an unwind (which is the correct action 4078b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // for a standard call). 4088b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach BasicBlock *UnwindBlock = BasicBlock::Create(F.getContext(), "unwindbb", &F); 4098b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Unwinds.push_back(new UnwindInst(F.getContext(), UnwindBlock)); 4108b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 4118b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *DispatchLoad = new LoadInst(CallSite, "invoke.num", true, 4128b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach DispatchBlock); 4138b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach SwitchInst *DispatchSwitch = 4148b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach SwitchInst::Create(DispatchLoad, UnwindBlock, Invokes.size(), DispatchBlock); 4158b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Split the entry block to insert the conditional branch for the setjmp. 4168b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach BasicBlock *ContBlock = EntryBB->splitBasicBlock(EntryBB->getTerminator(), 4178b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach "eh.sjlj.setjmp.cont"); 4188b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 4198b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Populate the Function Context 4208b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // 1. LSDA address 4218b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // 2. Personality function address 4228b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // 3. jmpbuf (save FP and call eh.sjlj.setjmp) 4238b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 4248b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // LSDA address 4258b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Idxs[0] = Zero; 4268b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Idxs[1] = ConstantInt::get(Int32Ty, 4); 4278b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *LSDAFieldPtr = 4288b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2, 4298b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach "lsda_gep", 4308b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach EntryBB->getTerminator()); 4318b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *LSDA = CallInst::Create(LSDAAddrFn, "lsda_addr", 4328b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach EntryBB->getTerminator()); 4338b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach new StoreInst(LSDA, LSDAFieldPtr, true, EntryBB->getTerminator()); 4348b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 4358b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Idxs[1] = ConstantInt::get(Int32Ty, 3); 4368b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *PersonalityFieldPtr = 4378b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2, 4388b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach "lsda_gep", 4398b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach EntryBB->getTerminator()); 4408b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach new StoreInst(PersonalityFn, PersonalityFieldPtr, true, 4418b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach EntryBB->getTerminator()); 4428b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 4438b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Save the frame pointer. 4448b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Idxs[1] = ConstantInt::get(Int32Ty, 5); 4458b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *FieldPtr 4468b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2, 4478b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach "jbuf_gep", 4488b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach EntryBB->getTerminator()); 4498b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Idxs[1] = ConstantInt::get(Int32Ty, 0); 4508b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *ElemPtr = 4518b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach GetElementPtrInst::Create(FieldPtr, Idxs, Idxs+2, "jbuf_fp_gep", 4528b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach EntryBB->getTerminator()); 4538b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 4548b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *Val = CallInst::Create(FrameAddrFn, 4558b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach ConstantInt::get(Int32Ty, 0), 4568b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach "fp", 4578b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach EntryBB->getTerminator()); 4588b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach new StoreInst(Val, ElemPtr, true, EntryBB->getTerminator()); 4598b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Call the setjmp instrinsic. It fills in the rest of the jmpbuf 4608b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *SetjmpArg = 4618b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach CastInst::Create(Instruction::BitCast, FieldPtr, 4628b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Type::getInt8Ty(F.getContext())->getPointerTo(), "", 4638b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach EntryBB->getTerminator()); 4648b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *DispatchVal = CallInst::Create(BuiltinSetjmpFn, SetjmpArg, 4658b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach "dispatch", 4668b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach EntryBB->getTerminator()); 4678b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // check the return value of the setjmp. non-zero goes to dispatcher 4688b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *IsNormal = new ICmpInst(EntryBB->getTerminator(), 4698b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach ICmpInst::ICMP_EQ, DispatchVal, Zero, 4708b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach "notunwind"); 4718b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Nuke the uncond branch. 4728b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach EntryBB->getTerminator()->eraseFromParent(); 4738b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 4748b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Put in a new condbranch in its place. 4758b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach BranchInst::Create(ContBlock, DispatchBlock, IsNormal, EntryBB); 4768b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 4778b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Register the function context and make sure it's known to not throw 4788b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach CallInst *Register = 4798b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach CallInst::Create(RegisterFn, FunctionContext, "", 4808b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach ContBlock->getTerminator()); 4818b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Register->setDoesNotThrow(); 4828b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 4838b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // At this point, we are all set up, update the invoke instructions 4848b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // to mark their call_site values, and fill in the dispatch switch 4858b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // accordingly. 4868b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (unsigned i = 0, e = Invokes.size(); i != e; ++i) 4878b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach markInvokeCallSite(Invokes[i], i+1, CallSite, DispatchSwitch); 4888b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 4898b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // The front end has likely added calls to _Unwind_Resume. We need 4908b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // to find those calls and mark the call_site as -1 immediately prior. 4918b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // resume is a noreturn function, so any block that has a call to it 4928b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // should end in an 'unreachable' instruction with the call immediately 4938b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // prior. That's how we'll search. 4948b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // ??? There's got to be a better way. this is fugly. 4958b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) 4968b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if ((dyn_cast<UnreachableInst>(BB->getTerminator()))) { 4978b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach BasicBlock::iterator I = BB->getTerminator(); 4988b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Check the previous instruction and see if it's a resume call 4998b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (I == BB->begin()) continue; 5008b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (CallInst *CI = dyn_cast<CallInst>(--I)) { 5018b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach if (CI->getCalledFunction() == ResumeFn) { 5028b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Value *NegativeOne = ConstantInt::get(Int32Ty, -1); 5038b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach new StoreInst(NegativeOne, CallSite, true, I); // volatile 5048b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 5058b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 5068b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 5078b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 5088b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Replace all unwinds with a branch to the unwind handler. 5098b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // ??? Should this ever happen with sjlj exceptions? 5108b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (unsigned i = 0, e = Unwinds.size(); i != e; ++i) { 5118b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach BranchInst::Create(UnwindBlock, Unwinds[i]); 5128b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach Unwinds[i]->eraseFromParent(); 5138b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 5148b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 5158b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // Finally, for any returns from this function, if this function contains an 5168b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach // invoke, add a call to unregister the function context. 5178b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach for (unsigned i = 0, e = Returns.size(); i != e; ++i) 5188b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach CallInst::Create(UnregisterFn, FunctionContext, "", Returns[i]); 5198b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach } 5208b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 5218b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach return true; 5228b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach} 5238b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach 5248b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbachbool SjLjEHPass::runOnFunction(Function &F) { 5258b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach bool Res = insertSjLjEHSupport(F); 5268b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach return Res; 5278b818d7e98309125c6058c4ea72a7dc73b031db2Jim Grosbach} 528