-//===- LowerInvoke.cpp - Eliminate Invoke & Unwind instructions -----------===//
+//===- LowerInvoke.cpp - Eliminate Invoke instructions --------------------===//
//
// The LLVM Compiler Infrastructure
//
//===----------------------------------------------------------------------===//
//
// This transformation is designed for use by code generators which do not yet
-// support stack unwinding. This pass supports two models of exception handling
-// lowering, the 'cheap' support and the 'expensive' support.
-//
-// 'Cheap' exception handling support gives the program the ability to execute
-// any program which does not "throw an exception", by turning 'invoke'
-// instructions into calls and by turning 'unwind' instructions into calls to
-// abort(). If the program does dynamically use the unwind instruction, the
-// program will print a message then abort.
-//
-// 'Expensive' exception handling support gives the full exception handling
-// support to the program at the cost of making the 'invoke' instruction
-// really expensive. It basically inserts setjmp/longjmp calls to emulate the
-// exception handling as necessary.
-//
-// Because the 'expensive' support slows down programs a lot, and EH is only
-// used for a subset of the programs, it must be specifically enabled by an
-// option.
-//
-// Note that after this pass runs the CFG is not entirely accurate (exceptional
-// control flow edges are not correct anymore) so only very simple things should
-// be done after the lowerinvoke pass has run (like generation of native code).
-// This should not be used as a general purpose "my LLVM-to-LLVM pass doesn't
-// support the invoke instruction yet" lowering pass.
+// support stack unwinding. This pass converts 'invoke' instructions to 'call'
+// instructions, so that any exception-handling 'landingpad' blocks become dead
+// code (which can be removed by running the '-simplifycfg' pass afterwards).
//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "lowerinvoke"
#include "llvm/Transforms/Scalar.h"
-#include "llvm/Constants.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/Instructions.h"
-#include "llvm/Intrinsics.h"
-#include "llvm/LLVMContext.h"
-#include "llvm/Module.h"
-#include "llvm/Pass.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Compiler.h"
-#include "llvm/Target/TargetLowering.h"
-#include <csetjmp>
-#include <set>
using namespace llvm;
-STATISTIC(NumInvokes, "Number of invokes replaced");
-STATISTIC(NumUnwinds, "Number of unwinds replaced");
-STATISTIC(NumSpilled, "Number of registers live across unwind edges");
+#define DEBUG_TYPE "lowerinvoke"
-static cl::opt<bool> ExpensiveEHSupport("enable-correct-eh-support",
- cl::desc("Make the -lowerinvoke pass insert expensive, but correct, EH code"));
+STATISTIC(NumInvokes, "Number of invokes replaced");
namespace {
- class VISIBILITY_HIDDEN LowerInvoke : public FunctionPass {
- // Used for both models.
- Constant *WriteFn;
- Constant *AbortFn;
- Value *AbortMessage;
- unsigned AbortMessageLength;
-
- // Used for expensive EH support.
- const Type *JBLinkTy;
- GlobalVariable *JBListHead;
- Constant *SetJmpFn, *LongJmpFn;
-
- // We peek in TLI to grab the target's jmp_buf size and alignment
- const TargetLowering *TLI;
-
+ class LowerInvoke : public FunctionPass {
public:
static char ID; // Pass identification, replacement for typeid
- explicit LowerInvoke(const TargetLowering *tli = NULL)
- : FunctionPass(&ID), TLI(tli) { }
- bool doInitialization(Module &M);
- bool runOnFunction(Function &F);
-
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- // This is a cluster of orthogonal Transforms
- AU.addPreservedID(PromoteMemoryToRegisterID);
- AU.addPreservedID(LowerSwitchID);
- AU.addPreservedID(LowerAllocationsID);
+ explicit LowerInvoke() : FunctionPass(ID) {
+ initializeLowerInvokePass(*PassRegistry::getPassRegistry());
}
-
- private:
- void createAbortMessage(Module *M);
- void writeAbortMessage(Instruction *IB);
- bool insertCheapEHSupport(Function &F);
- void splitLiveRangesLiveAcrossInvokes(std::vector<InvokeInst*> &Invokes);
- void rewriteExpensiveInvoke(InvokeInst *II, unsigned InvokeNo,
- AllocaInst *InvokeNum, SwitchInst *CatchSwitch);
- bool insertExpensiveEHSupport(Function &F);
+ bool runOnFunction(Function &F) override;
};
}
char LowerInvoke::ID = 0;
-static RegisterPass<LowerInvoke>
-X("lowerinvoke", "Lower invoke and unwind, for unwindless code generators");
+INITIALIZE_PASS(LowerInvoke, "lowerinvoke",
+ "Lower invoke and unwind, for unwindless code generators",
+ false, false)
-const PassInfo *const llvm::LowerInvokePassID = &X;
+char &llvm::LowerInvokePassID = LowerInvoke::ID;
// Public Interface To the LowerInvoke pass.
-FunctionPass *llvm::createLowerInvokePass(const TargetLowering *TLI) {
- return new LowerInvoke(TLI);
-}
-
-// doInitialization - Make sure that there is a prototype for abort in the
-// current module.
-bool LowerInvoke::doInitialization(Module &M) {
- const Type *VoidPtrTy = PointerType::getUnqual(Type::Int8Ty);
- AbortMessage = 0;
- if (ExpensiveEHSupport) {
- // Insert a type for the linked list of jump buffers.
- unsigned JBSize = TLI ? TLI->getJumpBufSize() : 0;
- JBSize = JBSize ? JBSize : 200;
- const Type *JmpBufTy = ArrayType::get(VoidPtrTy, JBSize);
-
- { // The type is recursive, so use a type holder.
- std::vector<const Type*> Elements;
- Elements.push_back(JmpBufTy);
- OpaqueType *OT = OpaqueType::get();
- Elements.push_back(PointerType::getUnqual(OT));
- PATypeHolder JBLType(StructType::get(Elements));
- OT->refineAbstractTypeTo(JBLType.get()); // Complete the cycle.
- JBLinkTy = JBLType.get();
- M.addTypeName("llvm.sjljeh.jmpbufty", JBLinkTy);
- }
-
- const Type *PtrJBList = PointerType::getUnqual(JBLinkTy);
-
- // Now that we've done that, insert the jmpbuf list head global, unless it
- // already exists.
- if (!(JBListHead = M.getGlobalVariable("llvm.sjljeh.jblist", PtrJBList))) {
- JBListHead = new GlobalVariable(M, PtrJBList, false,
- GlobalValue::LinkOnceAnyLinkage,
- Constant::getNullValue(PtrJBList),
- "llvm.sjljeh.jblist");
- }
-
-// VisualStudio defines setjmp as _setjmp via #include <csetjmp> / <setjmp.h>,
-// so it looks like Intrinsic::_setjmp
-#if defined(_MSC_VER) && defined(setjmp)
-#define setjmp_undefined_for_visual_studio
-#undef setjmp
-#endif
-
- SetJmpFn = Intrinsic::getDeclaration(&M, Intrinsic::setjmp);
-
-#if defined(_MSC_VER) && defined(setjmp_undefined_for_visual_studio)
-// let's return it to _setjmp state in case anyone ever needs it after this
-// point under VisualStudio
-#define setjmp _setjmp
-#endif
-
- LongJmpFn = Intrinsic::getDeclaration(&M, Intrinsic::longjmp);
- }
-
- // We need the 'write' and 'abort' functions for both models.
- AbortFn = M.getOrInsertFunction("abort", Type::VoidTy, (Type *)0);
-#if 0 // "write" is Unix-specific.. code is going away soon anyway.
- WriteFn = M.getOrInsertFunction("write", Type::VoidTy, Type::Int32Ty,
- VoidPtrTy, Type::Int32Ty, (Type *)0);
-#else
- WriteFn = 0;
-#endif
- return true;
+FunctionPass *llvm::createLowerInvokePass() {
+ return new LowerInvoke();
}
-void LowerInvoke::createAbortMessage(Module *M) {
- if (ExpensiveEHSupport) {
- // The abort message for expensive EH support tells the user that the
- // program 'unwound' without an 'invoke' instruction.
- Constant *Msg =
- ConstantArray::get("ERROR: Exception thrown, but not caught!\n");
- AbortMessageLength = Msg->getNumOperands()-1; // don't include \0
-
- GlobalVariable *MsgGV = new GlobalVariable(*M, Msg->getType(), true,
- GlobalValue::InternalLinkage,
- Msg, "abortmsg");
- std::vector<Constant*> GEPIdx(2, Constant::getNullValue(Type::Int32Ty));
- AbortMessage = ConstantExpr::getGetElementPtr(MsgGV, &GEPIdx[0], 2);
- } else {
- // The abort message for cheap EH support tells the user that EH is not
- // enabled.
- Constant *Msg =
- ConstantArray::get("Exception handler needed, but not enabled."
- "Recompile program with -enable-correct-eh-support.\n");
- AbortMessageLength = Msg->getNumOperands()-1; // don't include \0
-
- GlobalVariable *MsgGV = new GlobalVariable(*M, Msg->getType(), true,
- GlobalValue::InternalLinkage,
- Msg, "abortmsg");
- std::vector<Constant*> GEPIdx(2, Constant::getNullValue(Type::Int32Ty));
- AbortMessage = ConstantExpr::getGetElementPtr(MsgGV, &GEPIdx[0], 2);
- }
-}
-
-
-void LowerInvoke::writeAbortMessage(Instruction *IB) {
-#if 0
- if (AbortMessage == 0)
- createAbortMessage(IB->getParent()->getParent()->getParent());
-
- // These are the arguments we WANT...
- Value* Args[3];
- Args[0] = ConstantInt::get(Type::Int32Ty, 2);
- Args[1] = AbortMessage;
- Args[2] = ConstantInt::get(Type::Int32Ty, AbortMessageLength);
- (new CallInst(WriteFn, Args, 3, "", IB))->setTailCall();
-#endif
-}
-
-bool LowerInvoke::insertCheapEHSupport(Function &F) {
+bool LowerInvoke::runOnFunction(Function &F) {
bool Changed = false;
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
- std::vector<Value*> CallArgs(II->op_begin()+3, II->op_end());
+ SmallVector<Value*,16> CallArgs(II->op_begin(), II->op_end() - 3);
// Insert a normal call instruction...
CallInst *NewCall = CallInst::Create(II->getCalledValue(),
- CallArgs.begin(), CallArgs.end(), "",II);
+ CallArgs, "", II);
NewCall->takeName(II);
NewCall->setCallingConv(II->getCallingConv());
NewCall->setAttributes(II->getAttributes());
+ NewCall->setDebugLoc(II->getDebugLoc());
II->replaceAllUsesWith(NewCall);
// Insert an unconditional branch to the normal destination.
BB->getInstList().erase(II);
++NumInvokes; Changed = true;
- } else if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
- // Insert a new call to write(2, AbortMessage, AbortMessageLength);
- writeAbortMessage(UI);
-
- // Insert a call to abort()
- CallInst::Create(AbortFn, "", UI)->setTailCall();
-
- // Insert a return instruction. This really should be a "barrier", as it
- // is unreachable.
- ReturnInst::Create(F.getReturnType() == Type::VoidTy ? 0 :
- Constant::getNullValue(F.getReturnType()), UI);
-
- // Remove the unwind instruction now.
- BB->getInstList().erase(UI);
-
- ++NumUnwinds; Changed = true;
}
return Changed;
}
-
-/// rewriteExpensiveInvoke - Insert code and hack the function to replace the
-/// specified invoke instruction with a call.
-void LowerInvoke::rewriteExpensiveInvoke(InvokeInst *II, unsigned InvokeNo,
- AllocaInst *InvokeNum,
- SwitchInst *CatchSwitch) {
- ConstantInt *InvokeNoC = ConstantInt::get(Type::Int32Ty, InvokeNo);
-
- // If the unwind edge has phi nodes, split the edge.
- if (isa<PHINode>(II->getUnwindDest()->begin())) {
- SplitCriticalEdge(II, 1, this);
-
- // If there are any phi nodes left, they must have a single predecessor.
- while (PHINode *PN = dyn_cast<PHINode>(II->getUnwindDest()->begin())) {
- PN->replaceAllUsesWith(PN->getIncomingValue(0));
- PN->eraseFromParent();
- }
- }
-
- // Insert a store of the invoke num before the invoke and store zero into the
- // location afterward.
- new StoreInst(InvokeNoC, InvokeNum, true, II); // volatile
-
- BasicBlock::iterator NI = II->getNormalDest()->getFirstNonPHI();
- // nonvolatile.
- new StoreInst(Constant::getNullValue(Type::Int32Ty), InvokeNum, false, NI);
-
- // Add a switch case to our unwind block.
- CatchSwitch->addCase(InvokeNoC, II->getUnwindDest());
-
- // Insert a normal call instruction.
- std::vector<Value*> CallArgs(II->op_begin()+3, II->op_end());
- CallInst *NewCall = CallInst::Create(II->getCalledValue(),
- CallArgs.begin(), CallArgs.end(), "",
- II);
- NewCall->takeName(II);
- NewCall->setCallingConv(II->getCallingConv());
- NewCall->setAttributes(II->getAttributes());
- II->replaceAllUsesWith(NewCall);
-
- // Replace the invoke with an uncond branch.
- BranchInst::Create(II->getNormalDest(), NewCall->getParent());
- II->eraseFromParent();
-}
-
-/// MarkBlocksLiveIn - Insert BB and all of its predescessors into LiveBBs until
-/// we reach blocks we've already seen.
-static void MarkBlocksLiveIn(BasicBlock *BB, std::set<BasicBlock*> &LiveBBs) {
- if (!LiveBBs.insert(BB).second) return; // already been here.
-
- for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
- MarkBlocksLiveIn(*PI, LiveBBs);
-}
-
-// First thing we need to do is scan the whole function for values that are
-// live across unwind edges. Each value that is live across an unwind edge
-// we spill into a stack location, guaranteeing that there is nothing live
-// across the unwind edge. This process also splits all critical edges
-// coming out of invoke's.
-void LowerInvoke::
-splitLiveRangesLiveAcrossInvokes(std::vector<InvokeInst*> &Invokes) {
- // First step, split all critical edges from invoke instructions.
- for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
- InvokeInst *II = Invokes[i];
- SplitCriticalEdge(II, 0, this);
- SplitCriticalEdge(II, 1, this);
- assert(!isa<PHINode>(II->getNormalDest()) &&
- !isa<PHINode>(II->getUnwindDest()) &&
- "critical edge splitting left single entry phi nodes?");
- }
-
- Function *F = Invokes.back()->getParent()->getParent();
-
- // To avoid having to handle incoming arguments specially, we lower each arg
- // to a copy instruction in the entry block. This ensures that the argument
- // value itself cannot be live across the entry block.
- BasicBlock::iterator AfterAllocaInsertPt = F->begin()->begin();
- while (isa<AllocaInst>(AfterAllocaInsertPt) &&
- isa<ConstantInt>(cast<AllocaInst>(AfterAllocaInsertPt)->getArraySize()))
- ++AfterAllocaInsertPt;
- for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
- AI != E; ++AI) {
- // This is always a no-op cast because we're casting AI to AI->getType() so
- // src and destination types are identical. BitCast is the only possibility.
- CastInst *NC = new BitCastInst(
- AI, AI->getType(), AI->getName()+".tmp", AfterAllocaInsertPt);
- AI->replaceAllUsesWith(NC);
- // Normally its is forbidden to replace a CastInst's operand because it
- // could cause the opcode to reflect an illegal conversion. However, we're
- // replacing it here with the same value it was constructed with to simply
- // make NC its user.
- NC->setOperand(0, AI);
- }
-
- // Finally, scan the code looking for instructions with bad live ranges.
- for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
- for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E; ++II) {
- // Ignore obvious cases we don't have to handle. In particular, most
- // instructions either have no uses or only have a single use inside the
- // current block. Ignore them quickly.
- Instruction *Inst = II;
- if (Inst->use_empty()) continue;
- if (Inst->hasOneUse() &&
- cast<Instruction>(Inst->use_back())->getParent() == BB &&
- !isa<PHINode>(Inst->use_back())) continue;
-
- // If this is an alloca in the entry block, it's not a real register
- // value.
- if (AllocaInst *AI = dyn_cast<AllocaInst>(Inst))
- if (isa<ConstantInt>(AI->getArraySize()) && BB == F->begin())
- continue;
-
- // Avoid iterator invalidation by copying users to a temporary vector.
- std::vector<Instruction*> Users;
- for (Value::use_iterator UI = Inst->use_begin(), E = Inst->use_end();
- UI != E; ++UI) {
- Instruction *User = cast<Instruction>(*UI);
- if (User->getParent() != BB || isa<PHINode>(User))
- Users.push_back(User);
- }
-
- // Scan all of the uses and see if the live range is live across an unwind
- // edge. If we find a use live across an invoke edge, create an alloca
- // and spill the value.
- std::set<InvokeInst*> InvokesWithStoreInserted;
-
- // Find all of the blocks that this value is live in.
- std::set<BasicBlock*> LiveBBs;
- LiveBBs.insert(Inst->getParent());
- while (!Users.empty()) {
- Instruction *U = Users.back();
- Users.pop_back();
-
- if (!isa<PHINode>(U)) {
- MarkBlocksLiveIn(U->getParent(), LiveBBs);
- } else {
- // Uses for a PHI node occur in their predecessor block.
- PHINode *PN = cast<PHINode>(U);
- for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
- if (PN->getIncomingValue(i) == Inst)
- MarkBlocksLiveIn(PN->getIncomingBlock(i), LiveBBs);
- }
- }
-
- // Now that we know all of the blocks that this thing is live in, see if
- // it includes any of the unwind locations.
- bool NeedsSpill = false;
- for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
- BasicBlock *UnwindBlock = Invokes[i]->getUnwindDest();
- if (UnwindBlock != BB && LiveBBs.count(UnwindBlock)) {
- NeedsSpill = true;
- }
- }
-
- // If we decided we need a spill, do it.
- if (NeedsSpill) {
- ++NumSpilled;
- DemoteRegToStack(*Inst, true);
- }
- }
-}
-
-bool LowerInvoke::insertExpensiveEHSupport(Function &F) {
- std::vector<ReturnInst*> Returns;
- std::vector<UnwindInst*> Unwinds;
- std::vector<InvokeInst*> Invokes;
-
- for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
- if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
- // Remember all return instructions in case we insert an invoke into this
- // function.
- Returns.push_back(RI);
- } else if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
- Invokes.push_back(II);
- } else if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
- Unwinds.push_back(UI);
- }
-
- if (Unwinds.empty() && Invokes.empty()) return false;
-
- NumInvokes += Invokes.size();
- NumUnwinds += Unwinds.size();
-
- // TODO: This is not an optimal way to do this. In particular, this always
- // inserts setjmp calls into the entries of functions with invoke instructions
- // even though there are possibly paths through the function that do not
- // execute any invokes. In particular, for functions with early exits, e.g.
- // the 'addMove' method in hexxagon, it would be nice to not have to do the
- // setjmp stuff on the early exit path. This requires a bit of dataflow, but
- // would not be too hard to do.
-
- // If we have an invoke instruction, insert a setjmp that dominates all
- // invokes. After the setjmp, use a cond branch that goes to the original
- // code path on zero, and to a designated 'catch' block of nonzero.
- Value *OldJmpBufPtr = 0;
- if (!Invokes.empty()) {
- // First thing we need to do is scan the whole function for values that are
- // live across unwind edges. Each value that is live across an unwind edge
- // we spill into a stack location, guaranteeing that there is nothing live
- // across the unwind edge. This process also splits all critical edges
- // coming out of invoke's.
- splitLiveRangesLiveAcrossInvokes(Invokes);
-
- BasicBlock *EntryBB = F.begin();
-
- // Create an alloca for the incoming jump buffer ptr and the new jump buffer
- // that needs to be restored on all exits from the function. This is an
- // alloca because the value needs to be live across invokes.
- unsigned Align = TLI ? TLI->getJumpBufAlignment() : 0;
- AllocaInst *JmpBuf =
- new AllocaInst(JBLinkTy, 0, Align,
- "jblink", F.begin()->begin());
-
- std::vector<Value*> Idx;
- Idx.push_back(Constant::getNullValue(Type::Int32Ty));
- Idx.push_back(ConstantInt::get(Type::Int32Ty, 1));
- OldJmpBufPtr = GetElementPtrInst::Create(JmpBuf, Idx.begin(), Idx.end(),
- "OldBuf",
- EntryBB->getTerminator());
-
- // Copy the JBListHead to the alloca.
- Value *OldBuf = new LoadInst(JBListHead, "oldjmpbufptr", true,
- EntryBB->getTerminator());
- new StoreInst(OldBuf, OldJmpBufPtr, true, EntryBB->getTerminator());
-
- // Add the new jumpbuf to the list.
- new StoreInst(JmpBuf, JBListHead, true, EntryBB->getTerminator());
-
- // Create the catch block. The catch block is basically a big switch
- // statement that goes to all of the invoke catch blocks.
- BasicBlock *CatchBB = BasicBlock::Create("setjmp.catch", &F);
-
- // Create an alloca which keeps track of which invoke is currently
- // executing. For normal calls it contains zero.
- AllocaInst *InvokeNum = new AllocaInst(Type::Int32Ty, 0,
- "invokenum",EntryBB->begin());
- new StoreInst(ConstantInt::get(Type::Int32Ty, 0), InvokeNum, true,
- EntryBB->getTerminator());
-
- // Insert a load in the Catch block, and a switch on its value. By default,
- // we go to a block that just does an unwind (which is the correct action
- // for a standard call).
- BasicBlock *UnwindBB = BasicBlock::Create("unwindbb", &F);
- Unwinds.push_back(new UnwindInst(UnwindBB));
-
- Value *CatchLoad = new LoadInst(InvokeNum, "invoke.num", true, CatchBB);
- SwitchInst *CatchSwitch =
- SwitchInst::Create(CatchLoad, UnwindBB, Invokes.size(), CatchBB);
-
- // Now that things are set up, insert the setjmp call itself.
-
- // Split the entry block to insert the conditional branch for the setjmp.
- BasicBlock *ContBlock = EntryBB->splitBasicBlock(EntryBB->getTerminator(),
- "setjmp.cont");
-
- Idx[1] = ConstantInt::get(Type::Int32Ty, 0);
- Value *JmpBufPtr = GetElementPtrInst::Create(JmpBuf, Idx.begin(), Idx.end(),
- "TheJmpBuf",
- EntryBB->getTerminator());
- JmpBufPtr = new BitCastInst(JmpBufPtr, PointerType::getUnqual(Type::Int8Ty),
- "tmp", EntryBB->getTerminator());
- Value *SJRet = CallInst::Create(SetJmpFn, JmpBufPtr, "sjret",
- EntryBB->getTerminator());
-
- // Compare the return value to zero.
- Value *IsNormal = new ICmpInst(EntryBB->getTerminator(),
- ICmpInst::ICMP_EQ, SJRet,
- Constant::getNullValue(SJRet->getType()),
- "notunwind");
- // Nuke the uncond branch.
- EntryBB->getTerminator()->eraseFromParent();
-
- // Put in a new condbranch in its place.
- BranchInst::Create(ContBlock, CatchBB, IsNormal, EntryBB);
-
- // At this point, we are all set up, rewrite each invoke instruction.
- for (unsigned i = 0, e = Invokes.size(); i != e; ++i)
- rewriteExpensiveInvoke(Invokes[i], i+1, InvokeNum, CatchSwitch);
- }
-
- // We know that there is at least one unwind.
-
- // Create three new blocks, the block to load the jmpbuf ptr and compare
- // against null, the block to do the longjmp, and the error block for if it
- // is null. Add them at the end of the function because they are not hot.
- BasicBlock *UnwindHandler = BasicBlock::Create("dounwind", &F);
- BasicBlock *UnwindBlock = BasicBlock::Create("unwind", &F);
- BasicBlock *TermBlock = BasicBlock::Create("unwinderror", &F);
-
- // If this function contains an invoke, restore the old jumpbuf ptr.
- Value *BufPtr;
- if (OldJmpBufPtr) {
- // Before the return, insert a copy from the saved value to the new value.
- BufPtr = new LoadInst(OldJmpBufPtr, "oldjmpbufptr", UnwindHandler);
- new StoreInst(BufPtr, JBListHead, UnwindHandler);
- } else {
- BufPtr = new LoadInst(JBListHead, "ehlist", UnwindHandler);
- }
-
- // Load the JBList, if it's null, then there was no catch!
- Value *NotNull = new ICmpInst(*UnwindHandler, ICmpInst::ICMP_NE, BufPtr,
- Constant::getNullValue(BufPtr->getType()),
- "notnull");
- BranchInst::Create(UnwindBlock, TermBlock, NotNull, UnwindHandler);
-
- // Create the block to do the longjmp.
- // Get a pointer to the jmpbuf and longjmp.
- std::vector<Value*> Idx;
- Idx.push_back(Constant::getNullValue(Type::Int32Ty));
- Idx.push_back(ConstantInt::get(Type::Int32Ty, 0));
- Idx[0] = GetElementPtrInst::Create(BufPtr, Idx.begin(), Idx.end(), "JmpBuf",
- UnwindBlock);
- Idx[0] = new BitCastInst(Idx[0], PointerType::getUnqual(Type::Int8Ty),
- "tmp", UnwindBlock);
- Idx[1] = ConstantInt::get(Type::Int32Ty, 1);
- CallInst::Create(LongJmpFn, Idx.begin(), Idx.end(), "", UnwindBlock);
- new UnreachableInst(UnwindBlock);
-
- // Set up the term block ("throw without a catch").
- new UnreachableInst(TermBlock);
-
- // Insert a new call to write(2, AbortMessage, AbortMessageLength);
- writeAbortMessage(TermBlock->getTerminator());
-
- // Insert a call to abort()
- CallInst::Create(AbortFn, "",
- TermBlock->getTerminator())->setTailCall();
-
-
- // Replace all unwinds with a branch to the unwind handler.
- for (unsigned i = 0, e = Unwinds.size(); i != e; ++i) {
- BranchInst::Create(UnwindHandler, Unwinds[i]);
- Unwinds[i]->eraseFromParent();
- }
-
- // Finally, for any returns from this function, if this function contains an
- // invoke, restore the old jmpbuf pointer to its input value.
- if (OldJmpBufPtr) {
- for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
- ReturnInst *R = Returns[i];
-
- // Before the return, insert a copy from the saved value to the new value.
- Value *OldBuf = new LoadInst(OldJmpBufPtr, "oldjmpbufptr", true, R);
- new StoreInst(OldBuf, JBListHead, true, R);
- }
- }
-
- return true;
-}
-
-bool LowerInvoke::runOnFunction(Function &F) {
- if (ExpensiveEHSupport)
- return insertExpensiveEHSupport(F);
- else
- return insertCheapEHSupport(F);
-}
projects / oota-llvm.git / blobdiff