1 //===- SjLjEHPass.cpp - Eliminate Invoke & Unwind instructions -----------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This transformation is designed for use by code generators which use SjLj
11 // based exception handling.
13 //===----------------------------------------------------------------------===//
15 #define DEBUG_TYPE "sjljehprepare"
16 #include "llvm/Transforms/Scalar.h"
17 #include "llvm/Constants.h"
18 #include "llvm/DerivedTypes.h"
19 #include "llvm/Instructions.h"
20 #include "llvm/Intrinsics.h"
21 #include "llvm/LLVMContext.h"
22 #include "llvm/Module.h"
23 #include "llvm/Pass.h"
24 #include "llvm/CodeGen/Passes.h"
25 #include "llvm/Target/TargetLowering.h"
26 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
27 #include "llvm/Transforms/Utils/Local.h"
28 #include "llvm/Support/Debug.h"
29 #include "llvm/ADT/DenseMap.h"
30 #include "llvm/ADT/SmallVector.h"
31 #include "llvm/ADT/Statistic.h"
35 STATISTIC(NumInvokes, "Number of invokes replaced");
36 STATISTIC(NumUnwinds, "Number of unwinds replaced");
37 STATISTIC(NumSpilled, "Number of registers live across unwind edges");
40 class SjLjEHPass : public FunctionPass {
41 const TargetLowering *TLI;
42 Type *FunctionContextTy;
44 Constant *UnregisterFn;
45 Constant *BuiltinSetjmpFn;
46 Constant *FrameAddrFn;
47 Constant *StackAddrFn;
48 Constant *StackRestoreFn;
52 Constant *ExceptionFn;
54 Constant *DispatchSetupFn;
56 DenseMap<InvokeInst*, BasicBlock*> LPadSuccMap;
58 static char ID; // Pass identification, replacement for typeid
59 explicit SjLjEHPass(const TargetLowering *tli = NULL)
60 : FunctionPass(ID), TLI(tli) { }
61 bool doInitialization(Module &M);
62 bool runOnFunction(Function &F);
64 virtual void getAnalysisUsage(AnalysisUsage &AU) const {}
65 const char *getPassName() const {
66 return "SJLJ Exception Handling preparation";
70 void insertCallSiteStore(Instruction *I, int Number, Value *CallSite);
71 void markInvokeCallSite(InvokeInst *II, int InvokeNo, Value *CallSite,
72 SwitchInst *CatchSwitch);
73 void splitLiveRangesAcrossInvokes(SmallVector<InvokeInst*,16> &Invokes);
74 void splitLandingPad(InvokeInst *II);
75 bool insertSjLjEHSupport(Function &F);
77 } // end anonymous namespace
79 char SjLjEHPass::ID = 0;
81 // Public Interface To the SjLjEHPass pass.
82 FunctionPass *llvm::createSjLjEHPass(const TargetLowering *TLI) {
83 return new SjLjEHPass(TLI);
85 // doInitialization - Set up decalarations and types needed to process
87 bool SjLjEHPass::doInitialization(Module &M) {
88 // Build the function context structure.
89 // builtin_setjmp uses a five word jbuf
90 Type *VoidPtrTy = Type::getInt8PtrTy(M.getContext());
91 Type *Int32Ty = Type::getInt32Ty(M.getContext());
93 StructType::get(VoidPtrTy, // __prev
95 ArrayType::get(Int32Ty, 4), // __data
96 VoidPtrTy, // __personality
98 ArrayType::get(VoidPtrTy, 5), // __jbuf
100 RegisterFn = M.getOrInsertFunction("_Unwind_SjLj_Register",
101 Type::getVoidTy(M.getContext()),
102 PointerType::getUnqual(FunctionContextTy),
105 M.getOrInsertFunction("_Unwind_SjLj_Unregister",
106 Type::getVoidTy(M.getContext()),
107 PointerType::getUnqual(FunctionContextTy),
109 FrameAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::frameaddress);
110 StackAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::stacksave);
111 StackRestoreFn = Intrinsic::getDeclaration(&M, Intrinsic::stackrestore);
112 BuiltinSetjmpFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_setjmp);
113 LSDAAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_lsda);
114 SelectorFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_selector);
115 ExceptionFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_exception);
116 CallSiteFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_callsite);
118 = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_dispatch_setup);
124 /// insertCallSiteStore - Insert a store of the call-site value to the
126 void SjLjEHPass::insertCallSiteStore(Instruction *I, int Number,
128 ConstantInt *CallSiteNoC = ConstantInt::get(Type::getInt32Ty(I->getContext()),
130 // Insert a store of the call-site number
131 new StoreInst(CallSiteNoC, CallSite, true, I); // volatile
134 /// splitLandingPad - Split a landing pad. This takes considerable care because
135 /// of PHIs and other nasties. The problem is that the jump table needs to jump
136 /// to the landing pad block. However, the landing pad block can be jumped to
137 /// only by an invoke instruction. So we clone the landingpad instruction into
138 /// its own basic block, have the invoke jump to there. The landingpad
139 /// instruction's basic block's successor is now the target for the jump table.
141 /// But because of PHI nodes, we need to create another basic block for the jump
142 /// table to jump to. This is definitely a hack, because the values for the PHI
143 /// nodes may not be defined on the edge from the jump table. But that's okay,
144 /// because the jump table is simply a construct to mimic what is happening in
145 /// the CFG. So the values are mysteriously there, even though there is no value
146 /// for the PHI from the jump table's edge (hence calling this a hack).
147 void SjLjEHPass::splitLandingPad(InvokeInst *II) {
148 SmallVector<BasicBlock*, 2> NewBBs;
149 SplitLandingPadPredecessors(II->getUnwindDest(), II->getParent(),
150 ".1", ".2", this, NewBBs);
152 // Create an empty block so that the jump table has something to jump to
153 // which doesn't have any PHI nodes.
154 BasicBlock *LPad = NewBBs[0];
155 BasicBlock *Succ = *succ_begin(LPad);
156 BasicBlock *JumpTo = BasicBlock::Create(II->getContext(), "jt.land",
157 LPad->getParent(), Succ);
158 LPad->getTerminator()->eraseFromParent();
159 BranchInst::Create(JumpTo, LPad);
160 BranchInst::Create(Succ, JumpTo);
161 LPadSuccMap[II] = JumpTo;
163 for (BasicBlock::iterator I = Succ->begin(); isa<PHINode>(I); ++I) {
164 PHINode *PN = cast<PHINode>(I);
165 Value *Val = PN->removeIncomingValue(LPad, false);
166 PN->addIncoming(Val, JumpTo);
170 /// markInvokeCallSite - Insert code to mark the call_site for this invoke
171 void SjLjEHPass::markInvokeCallSite(InvokeInst *II, int InvokeNo,
173 SwitchInst *CatchSwitch) {
174 ConstantInt *CallSiteNoC= ConstantInt::get(Type::getInt32Ty(II->getContext()),
176 // The runtime comes back to the dispatcher with the call_site - 1 in
177 // the context. Odd, but there it is.
178 ConstantInt *SwitchValC = ConstantInt::get(Type::getInt32Ty(II->getContext()),
181 // If the unwind edge has phi nodes, split the edge.
182 if (isa<PHINode>(II->getUnwindDest()->begin())) {
183 // FIXME: New EH - This if-condition will be always true in the new scheme.
184 if (II->getUnwindDest()->isLandingPad())
187 SplitCriticalEdge(II, 1, this);
189 // If there are any phi nodes left, they must have a single predecessor.
190 while (PHINode *PN = dyn_cast<PHINode>(II->getUnwindDest()->begin())) {
191 PN->replaceAllUsesWith(PN->getIncomingValue(0));
192 PN->eraseFromParent();
196 // Insert the store of the call site value
197 insertCallSiteStore(II, InvokeNo, CallSite);
199 // Record the call site value for the back end so it stays associated with
201 CallInst::Create(CallSiteFn, CallSiteNoC, "", II);
203 // Add a switch case to our unwind block.
204 if (BasicBlock *SuccBB = LPadSuccMap[II]) {
205 CatchSwitch->addCase(SwitchValC, SuccBB);
207 CatchSwitch->addCase(SwitchValC, II->getUnwindDest());
210 // We still want this to look like an invoke so we emit the LSDA properly,
211 // so we don't transform the invoke into a call here.
214 /// MarkBlocksLiveIn - Insert BB and all of its predescessors into LiveBBs until
215 /// we reach blocks we've already seen.
216 static void MarkBlocksLiveIn(BasicBlock *BB, std::set<BasicBlock*> &LiveBBs) {
217 if (!LiveBBs.insert(BB).second) return; // already been here.
219 for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
220 MarkBlocksLiveIn(*PI, LiveBBs);
223 /// splitLiveRangesAcrossInvokes - Each value that is live across an unwind edge
224 /// we spill into a stack location, guaranteeing that there is nothing live
225 /// across the unwind edge. This process also splits all critical edges
226 /// coming out of invoke's.
227 /// FIXME: Move this function to a common utility file (Local.cpp?) so
228 /// both SjLj and LowerInvoke can use it.
230 splitLiveRangesAcrossInvokes(SmallVector<InvokeInst*,16> &Invokes) {
231 // First step, split all critical edges from invoke instructions.
232 for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
233 InvokeInst *II = Invokes[i];
234 SplitCriticalEdge(II, 0, this);
236 // FIXME: New EH - This if-condition will be always true in the new scheme.
237 if (II->getUnwindDest()->isLandingPad())
240 SplitCriticalEdge(II, 1, this);
242 assert(!isa<PHINode>(II->getNormalDest()) &&
243 !isa<PHINode>(II->getUnwindDest()) &&
244 "Critical edge splitting left single entry phi nodes?");
247 Function *F = Invokes.back()->getParent()->getParent();
249 // To avoid having to handle incoming arguments specially, we lower each arg
250 // to a copy instruction in the entry block. This ensures that the argument
251 // value itself cannot be live across the entry block.
252 BasicBlock::iterator AfterAllocaInsertPt = F->begin()->begin();
253 while (isa<AllocaInst>(AfterAllocaInsertPt) &&
254 isa<ConstantInt>(cast<AllocaInst>(AfterAllocaInsertPt)->getArraySize()))
255 ++AfterAllocaInsertPt;
256 for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
258 Type *Ty = AI->getType();
259 // Aggregate types can't be cast, but are legal argument types, so we have
260 // to handle them differently. We use an extract/insert pair as a
261 // lightweight method to achieve the same goal.
262 if (isa<StructType>(Ty) || isa<ArrayType>(Ty) || isa<VectorType>(Ty)) {
263 Instruction *EI = ExtractValueInst::Create(AI, 0, "",AfterAllocaInsertPt);
264 Instruction *NI = InsertValueInst::Create(AI, EI, 0);
266 AI->replaceAllUsesWith(NI);
267 // Set the operand of the instructions back to the AllocaInst.
268 EI->setOperand(0, AI);
269 NI->setOperand(0, AI);
271 // This is always a no-op cast because we're casting AI to AI->getType()
272 // so src and destination types are identical. BitCast is the only
274 CastInst *NC = new BitCastInst(
275 AI, AI->getType(), AI->getName()+".tmp", AfterAllocaInsertPt);
276 AI->replaceAllUsesWith(NC);
277 // Set the operand of the cast instruction back to the AllocaInst.
278 // Normally it's forbidden to replace a CastInst's operand because it
279 // could cause the opcode to reflect an illegal conversion. However,
280 // we're replacing it here with the same value it was constructed with.
281 // We do this because the above replaceAllUsesWith() clobbered the
282 // operand, but we want this one to remain.
283 NC->setOperand(0, AI);
287 // Finally, scan the code looking for instructions with bad live ranges.
288 for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
289 for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E; ++II) {
290 // Ignore obvious cases we don't have to handle. In particular, most
291 // instructions either have no uses or only have a single use inside the
292 // current block. Ignore them quickly.
293 Instruction *Inst = II;
294 if (Inst->use_empty()) continue;
295 if (Inst->hasOneUse() &&
296 cast<Instruction>(Inst->use_back())->getParent() == BB &&
297 !isa<PHINode>(Inst->use_back())) continue;
299 // If this is an alloca in the entry block, it's not a real register
301 if (AllocaInst *AI = dyn_cast<AllocaInst>(Inst))
302 if (isa<ConstantInt>(AI->getArraySize()) && BB == F->begin())
305 // Avoid iterator invalidation by copying users to a temporary vector.
306 SmallVector<Instruction*,16> Users;
307 for (Value::use_iterator UI = Inst->use_begin(), E = Inst->use_end();
309 Instruction *User = cast<Instruction>(*UI);
310 if (User->getParent() != BB || isa<PHINode>(User))
311 Users.push_back(User);
314 // Find all of the blocks that this value is live in.
315 std::set<BasicBlock*> LiveBBs;
316 LiveBBs.insert(Inst->getParent());
317 while (!Users.empty()) {
318 Instruction *U = Users.back();
321 if (!isa<PHINode>(U)) {
322 MarkBlocksLiveIn(U->getParent(), LiveBBs);
324 // Uses for a PHI node occur in their predecessor block.
325 PHINode *PN = cast<PHINode>(U);
326 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
327 if (PN->getIncomingValue(i) == Inst)
328 MarkBlocksLiveIn(PN->getIncomingBlock(i), LiveBBs);
332 // Now that we know all of the blocks that this thing is live in, see if
333 // it includes any of the unwind locations.
334 bool NeedsSpill = false;
335 for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
336 BasicBlock *UnwindBlock = Invokes[i]->getUnwindDest();
337 if (UnwindBlock != BB && LiveBBs.count(UnwindBlock)) {
342 // If we decided we need a spill, do it.
343 // FIXME: Spilling this way is overkill, as it forces all uses of
344 // the value to be reloaded from the stack slot, even those that aren't
345 // in the unwind blocks. We should be more selective.
348 DemoteRegToStack(*Inst, true);
353 /// CreateLandingPadLoad - Load the exception handling values and insert them
354 /// into a structure.
355 static Instruction *CreateLandingPadLoad(Function &F, Value *ExnAddr,
357 BasicBlock::iterator InsertPt) {
358 Value *Exn = new LoadInst(ExnAddr, "exn", false,
360 Type *Ty = Type::getInt8PtrTy(F.getContext());
361 Exn = CastInst::Create(Instruction::IntToPtr, Exn, Ty, "", InsertPt);
362 Value *Sel = new LoadInst(SelAddr, "sel", false, InsertPt);
364 Ty = StructType::get(Exn->getType(), Sel->getType(), NULL);
365 InsertValueInst *LPadVal = InsertValueInst::Create(llvm::UndefValue::get(Ty),
367 "lpad.val", InsertPt);
368 return InsertValueInst::Create(LPadVal, Sel, 1, "lpad.val", InsertPt);
371 /// ReplaceLandingPadVal - Replace the landingpad instruction's value with a
372 /// load from the stored values (via CreateLandingPadLoad). This looks through
373 /// PHI nodes, and removes them if they are dead.
374 static void ReplaceLandingPadVal(Function &F, Instruction *Inst, Value *ExnAddr,
376 if (Inst->use_empty()) return;
378 while (!Inst->use_empty()) {
379 Instruction *I = cast<Instruction>(Inst->use_back());
381 if (PHINode *PN = dyn_cast<PHINode>(I)) {
382 ReplaceLandingPadVal(F, PN, ExnAddr, SelAddr);
383 if (PN->use_empty()) PN->eraseFromParent();
387 I->replaceUsesOfWith(Inst, CreateLandingPadLoad(F, ExnAddr, SelAddr, I));
391 bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
392 SmallVector<ReturnInst*,16> Returns;
393 SmallVector<UnwindInst*,16> Unwinds;
394 SmallVector<InvokeInst*,16> Invokes;
396 // Look through the terminators of the basic blocks to find invokes, returns
398 for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
399 if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
400 // Remember all return instructions in case we insert an invoke into this
402 Returns.push_back(RI);
403 } else if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
404 Invokes.push_back(II);
405 } else if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
406 Unwinds.push_back(UI);
410 NumInvokes += Invokes.size();
411 NumUnwinds += Unwinds.size();
413 // If we don't have any invokes, there's nothing to do.
414 if (Invokes.empty()) return false;
416 // Find the eh.selector.*, eh.exception and alloca calls.
418 // Remember any allocas() that aren't in the entry block, as the
419 // jmpbuf saved SP will need to be updated for them.
421 // We'll use the first eh.selector to determine the right personality
422 // function to use. For SJLJ, we always use the same personality for the
423 // whole function, not on a per-selector basis.
424 // FIXME: That's a bit ugly. Better way?
425 SmallVector<CallInst*,16> EH_Selectors;
426 SmallVector<CallInst*,16> EH_Exceptions;
427 SmallVector<Instruction*,16> JmpbufUpdatePoints;
429 for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
430 // Note: Skip the entry block since there's nothing there that interests
431 // us. eh.selector and eh.exception shouldn't ever be there, and we
432 // want to disregard any allocas that are there.
434 // FIXME: This is awkward. The new EH scheme won't need to skip the entry
436 if (BB == F.begin()) {
437 if (InvokeInst *II = dyn_cast<InvokeInst>(F.begin()->getTerminator())) {
438 // FIXME: This will be always non-NULL in the new EH.
439 if (LandingPadInst *LPI = II->getUnwindDest()->getLandingPadInst())
440 if (!PersonalityFn) PersonalityFn = LPI->getPersonalityFn();
446 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
447 if (CallInst *CI = dyn_cast<CallInst>(I)) {
448 if (CI->getCalledFunction() == SelectorFn) {
449 if (!PersonalityFn) PersonalityFn = CI->getArgOperand(1);
450 EH_Selectors.push_back(CI);
451 } else if (CI->getCalledFunction() == ExceptionFn) {
452 EH_Exceptions.push_back(CI);
453 } else if (CI->getCalledFunction() == StackRestoreFn) {
454 JmpbufUpdatePoints.push_back(CI);
456 } else if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
457 JmpbufUpdatePoints.push_back(AI);
458 } else if (InvokeInst *II = dyn_cast<InvokeInst>(I)) {
459 // FIXME: This will be always non-NULL in the new EH.
460 if (LandingPadInst *LPI = II->getUnwindDest()->getLandingPadInst())
461 if (!PersonalityFn) PersonalityFn = LPI->getPersonalityFn();
466 // If we don't have any eh.selector calls, we can't determine the personality
467 // function. Without a personality function, we can't process exceptions.
468 if (!PersonalityFn) return false;
470 // We have invokes, so we need to add register/unregister calls to get this
471 // function onto the global unwind stack.
473 // First thing we need to do is scan the whole function for values that are
474 // live across unwind edges. Each value that is live across an unwind edge we
475 // spill into a stack location, guaranteeing that there is nothing live across
476 // the unwind edge. This process also splits all critical edges coming out of
478 splitLiveRangesAcrossInvokes(Invokes);
481 SmallVector<LandingPadInst*, 16> LandingPads;
482 for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
483 if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator()))
484 // FIXME: This will be always non-NULL in the new EH.
485 if (LandingPadInst *LPI = II->getUnwindDest()->getLandingPadInst())
486 LandingPads.push_back(LPI);
490 BasicBlock *EntryBB = F.begin();
491 // Create an alloca for the incoming jump buffer ptr and the new jump buffer
492 // that needs to be restored on all exits from the function. This is an
493 // alloca because the value needs to be added to the global context list.
494 unsigned Align = 4; // FIXME: Should be a TLI check?
495 AllocaInst *FunctionContext =
496 new AllocaInst(FunctionContextTy, 0, Align,
497 "fcn_context", F.begin()->begin());
500 Type *Int32Ty = Type::getInt32Ty(F.getContext());
501 Value *Zero = ConstantInt::get(Int32Ty, 0);
502 // We need to also keep around a reference to the call_site field
504 Idxs[1] = ConstantInt::get(Int32Ty, 1);
505 CallSite = GetElementPtrInst::Create(FunctionContext, Idxs, "call_site",
506 EntryBB->getTerminator());
508 // The exception selector comes back in context->data[1]
509 Idxs[1] = ConstantInt::get(Int32Ty, 2);
510 Value *FCData = GetElementPtrInst::Create(FunctionContext, Idxs, "fc_data",
511 EntryBB->getTerminator());
512 Idxs[1] = ConstantInt::get(Int32Ty, 1);
513 Value *SelectorAddr = GetElementPtrInst::Create(FCData, Idxs,
515 EntryBB->getTerminator());
516 // The exception value comes back in context->data[0]
518 Value *ExceptionAddr = GetElementPtrInst::Create(FCData, Idxs,
520 EntryBB->getTerminator());
522 // The result of the eh.selector call will be replaced with a a reference to
523 // the selector value returned in the function context. We leave the selector
524 // itself so the EH analysis later can use it.
525 for (int i = 0, e = EH_Selectors.size(); i < e; ++i) {
526 CallInst *I = EH_Selectors[i];
527 Value *SelectorVal = new LoadInst(SelectorAddr, "select_val", true, I);
528 I->replaceAllUsesWith(SelectorVal);
531 // eh.exception calls are replaced with references to the proper location in
532 // the context. Unlike eh.selector, the eh.exception calls are removed
534 for (int i = 0, e = EH_Exceptions.size(); i < e; ++i) {
535 CallInst *I = EH_Exceptions[i];
536 // Possible for there to be duplicates, so check to make sure the
537 // instruction hasn't already been removed.
538 if (!I->getParent()) continue;
539 Value *Val = new LoadInst(ExceptionAddr, "exception", true, I);
540 Type *Ty = Type::getInt8PtrTy(F.getContext());
541 Val = CastInst::Create(Instruction::IntToPtr, Val, Ty, "", I);
543 I->replaceAllUsesWith(Val);
544 I->eraseFromParent();
547 for (unsigned i = 0, e = LandingPads.size(); i != e; ++i)
548 ReplaceLandingPadVal(F, LandingPads[i], ExceptionAddr, SelectorAddr);
550 // The entry block changes to have the eh.sjlj.setjmp, with a conditional
551 // branch to a dispatch block for non-zero returns. If we return normally,
552 // we're not handling an exception and just register the function context and
555 // Create the dispatch block. The dispatch block is basically a big switch
556 // statement that goes to all of the invoke landing pads.
557 BasicBlock *DispatchBlock =
558 BasicBlock::Create(F.getContext(), "eh.sjlj.setjmp.catch", &F);
560 // Insert a load of the callsite in the dispatch block, and a switch on its
561 // value. By default, we issue a trap statement.
562 BasicBlock *TrapBlock =
563 BasicBlock::Create(F.getContext(), "trapbb", &F);
564 CallInst::Create(Intrinsic::getDeclaration(F.getParent(), Intrinsic::trap),
566 new UnreachableInst(F.getContext(), TrapBlock);
568 Value *DispatchLoad = new LoadInst(CallSite, "invoke.num", true,
570 SwitchInst *DispatchSwitch =
571 SwitchInst::Create(DispatchLoad, TrapBlock, Invokes.size(),
573 // Split the entry block to insert the conditional branch for the setjmp.
574 BasicBlock *ContBlock = EntryBB->splitBasicBlock(EntryBB->getTerminator(),
575 "eh.sjlj.setjmp.cont");
577 // Populate the Function Context
579 // 2. Personality function address
580 // 3. jmpbuf (save SP, FP and call eh.sjlj.setjmp)
584 Idxs[1] = ConstantInt::get(Int32Ty, 4);
585 Value *LSDAFieldPtr =
586 GetElementPtrInst::Create(FunctionContext, Idxs, "lsda_gep",
587 EntryBB->getTerminator());
588 Value *LSDA = CallInst::Create(LSDAAddrFn, "lsda_addr",
589 EntryBB->getTerminator());
590 new StoreInst(LSDA, LSDAFieldPtr, true, EntryBB->getTerminator());
592 Idxs[1] = ConstantInt::get(Int32Ty, 3);
593 Value *PersonalityFieldPtr =
594 GetElementPtrInst::Create(FunctionContext, Idxs, "lsda_gep",
595 EntryBB->getTerminator());
596 new StoreInst(PersonalityFn, PersonalityFieldPtr, true,
597 EntryBB->getTerminator());
599 // Save the frame pointer.
600 Idxs[1] = ConstantInt::get(Int32Ty, 5);
602 = GetElementPtrInst::Create(FunctionContext, Idxs, "jbuf_gep",
603 EntryBB->getTerminator());
604 Idxs[1] = ConstantInt::get(Int32Ty, 0);
606 GetElementPtrInst::Create(JBufPtr, Idxs, "jbuf_fp_gep",
607 EntryBB->getTerminator());
609 Value *Val = CallInst::Create(FrameAddrFn,
610 ConstantInt::get(Int32Ty, 0),
612 EntryBB->getTerminator());
613 new StoreInst(Val, FramePtr, true, EntryBB->getTerminator());
615 // Save the stack pointer.
616 Idxs[1] = ConstantInt::get(Int32Ty, 2);
618 GetElementPtrInst::Create(JBufPtr, Idxs, "jbuf_sp_gep",
619 EntryBB->getTerminator());
621 Val = CallInst::Create(StackAddrFn, "sp", EntryBB->getTerminator());
622 new StoreInst(Val, StackPtr, true, EntryBB->getTerminator());
624 // Call the setjmp instrinsic. It fills in the rest of the jmpbuf.
626 CastInst::Create(Instruction::BitCast, JBufPtr,
627 Type::getInt8PtrTy(F.getContext()), "",
628 EntryBB->getTerminator());
629 Value *DispatchVal = CallInst::Create(BuiltinSetjmpFn, SetjmpArg,
631 EntryBB->getTerminator());
633 // Add a call to dispatch_setup after the setjmp call. This is expanded to any
634 // target-specific setup that needs to be done.
635 CallInst::Create(DispatchSetupFn, DispatchVal, "", EntryBB->getTerminator());
637 // check the return value of the setjmp. non-zero goes to dispatcher.
638 Value *IsNormal = new ICmpInst(EntryBB->getTerminator(),
639 ICmpInst::ICMP_EQ, DispatchVal, Zero,
641 // Nuke the uncond branch.
642 EntryBB->getTerminator()->eraseFromParent();
644 // Put in a new condbranch in its place.
645 BranchInst::Create(ContBlock, DispatchBlock, IsNormal, EntryBB);
647 // Register the function context and make sure it's known to not throw
649 CallInst::Create(RegisterFn, FunctionContext, "",
650 ContBlock->getTerminator());
651 Register->setDoesNotThrow();
653 // At this point, we are all set up, update the invoke instructions to mark
654 // their call_site values, and fill in the dispatch switch accordingly.
655 for (unsigned i = 0, e = Invokes.size(); i != e; ++i)
656 markInvokeCallSite(Invokes[i], i+1, CallSite, DispatchSwitch);
658 // Mark call instructions that aren't nounwind as no-action (call_site ==
659 // -1). Skip the entry block, as prior to then, no function context has been
660 // created for this function and any unexpected exceptions thrown will go
661 // directly to the caller's context, which is what we want anyway, so no need
662 // to do anything here.
663 for (Function::iterator BB = F.begin(), E = F.end(); ++BB != E;) {
664 for (BasicBlock::iterator I = BB->begin(), end = BB->end(); I != end; ++I)
665 if (CallInst *CI = dyn_cast<CallInst>(I)) {
666 // Ignore calls to the EH builtins (eh.selector, eh.exception)
667 Constant *Callee = CI->getCalledFunction();
668 if (Callee != SelectorFn && Callee != ExceptionFn
669 && !CI->doesNotThrow())
670 insertCallSiteStore(CI, -1, CallSite);
671 } else if (ResumeInst *RI = dyn_cast<ResumeInst>(I)) {
672 insertCallSiteStore(RI, -1, CallSite);
676 // Replace all unwinds with a branch to the unwind handler.
677 // ??? Should this ever happen with sjlj exceptions?
678 for (unsigned i = 0, e = Unwinds.size(); i != e; ++i) {
679 BranchInst::Create(TrapBlock, Unwinds[i]);
680 Unwinds[i]->eraseFromParent();
683 // Following any allocas not in the entry block, update the saved SP in the
684 // jmpbuf to the new value.
685 for (unsigned i = 0, e = JmpbufUpdatePoints.size(); i != e; ++i) {
686 Instruction *AI = JmpbufUpdatePoints[i];
687 Instruction *StackAddr = CallInst::Create(StackAddrFn, "sp");
688 StackAddr->insertAfter(AI);
689 Instruction *StoreStackAddr = new StoreInst(StackAddr, StackPtr, true);
690 StoreStackAddr->insertAfter(StackAddr);
693 // Finally, for any returns from this function, if this function contains an
694 // invoke, add a call to unregister the function context.
695 for (unsigned i = 0, e = Returns.size(); i != e; ++i)
696 CallInst::Create(UnregisterFn, FunctionContext, "", Returns[i]);
701 bool SjLjEHPass::runOnFunction(Function &F) {
702 bool Res = insertSjLjEHSupport(F);