1 //===- SjLjEHPrepare.cpp - Eliminate Invoke & Unwind instructions ---------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This transformation is designed for use by code generators which use SjLj
10 // based exception handling.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "llvm/CodeGen/SjLjEHPrepare.h"
15 #include "llvm/ADT/SetVector.h"
16 #include "llvm/ADT/SmallPtrSet.h"
17 #include "llvm/ADT/SmallVector.h"
18 #include "llvm/ADT/Statistic.h"
19 #include "llvm/CodeGen/Passes.h"
20 #include "llvm/IR/Constants.h"
21 #include "llvm/IR/DataLayout.h"
22 #include "llvm/IR/DerivedTypes.h"
23 #include "llvm/IR/IRBuilder.h"
24 #include "llvm/IR/Instructions.h"
25 #include "llvm/IR/Intrinsics.h"
26 #include "llvm/IR/Module.h"
27 #include "llvm/InitializePasses.h"
28 #include "llvm/Pass.h"
29 #include "llvm/Support/Debug.h"
30 #include "llvm/Support/raw_ostream.h"
31 #include "llvm/Target/TargetMachine.h"
32 #include "llvm/Transforms/Utils/Local.h"
33 using namespace llvm;
34
35 #define DEBUG_TYPE "sjlj-eh-prepare"
36
37 STATISTIC(NumInvokes, "Number of invokes replaced");
38 STATISTIC(NumSpilled, "Number of registers live across unwind edges");
39
40 namespace {
41 class SjLjEHPrepareImpl {
42 IntegerType *DataTy = nullptr;
43 Type *doubleUnderDataTy = nullptr;
44 Type *doubleUnderJBufTy = nullptr;
45 Type *FunctionContextTy = nullptr;
46 FunctionCallee RegisterFn;
47 FunctionCallee UnregisterFn;
48 Function *BuiltinSetupDispatchFn = nullptr;
49 Function *FrameAddrFn = nullptr;
50 Function *StackAddrFn = nullptr;
51 Function *StackRestoreFn = nullptr;
52 Function *LSDAAddrFn = nullptr;
53 Function *CallSiteFn = nullptr;
54 Function *FuncCtxFn = nullptr;
55 AllocaInst *FuncCtx = nullptr;
56 const TargetMachine *TM = nullptr;
57
58 public:
SjLjEHPrepareImpl(const TargetMachine * TM=nullptr)59 explicit SjLjEHPrepareImpl(const TargetMachine *TM = nullptr) : TM(TM) {}
60 bool doInitialization(Module &M);
61 bool runOnFunction(Function &F);
62
63 private:
64 bool setupEntryBlockAndCallSites(Function &F);
65 void substituteLPadValues(LandingPadInst *LPI, Value *ExnVal, Value *SelVal);
66 Value *setupFunctionContext(Function &F, ArrayRef<LandingPadInst *> LPads);
67 void lowerIncomingArguments(Function &F);
68 void lowerAcrossUnwindEdges(Function &F, ArrayRef<InvokeInst *> Invokes);
69 void insertCallSiteStore(Instruction *I, int Number);
70 };
71
72 class SjLjEHPrepare : public FunctionPass {
73 SjLjEHPrepareImpl Impl;
74
75 public:
76 static char ID; // Pass identification, replacement for typeid
SjLjEHPrepare(const TargetMachine * TM=nullptr)77 explicit SjLjEHPrepare(const TargetMachine *TM = nullptr)
78 : FunctionPass(ID), Impl(TM) {}
doInitialization(Module & M)79 bool doInitialization(Module &M) override { return Impl.doInitialization(M); }
runOnFunction(Function & F)80 bool runOnFunction(Function &F) override { return Impl.runOnFunction(F); };
81
getPassName() const82 StringRef getPassName() const override {
83 return "SJLJ Exception Handling preparation";
84 }
85 };
86
87 } // end anonymous namespace
88
run(Function & F,FunctionAnalysisManager & FAM)89 PreservedAnalyses SjLjEHPreparePass::run(Function &F,
90 FunctionAnalysisManager &FAM) {
91 SjLjEHPrepareImpl Impl(TM);
92 Impl.doInitialization(*F.getParent());
93 bool Changed = Impl.runOnFunction(F);
94 return Changed ? PreservedAnalyses::none() : PreservedAnalyses::all();
95 }
96
97 char SjLjEHPrepare::ID = 0;
98 INITIALIZE_PASS(SjLjEHPrepare, DEBUG_TYPE, "Prepare SjLj exceptions",
99 false, false)
100
101 // Public Interface To the SjLjEHPrepare pass.
createSjLjEHPreparePass(const TargetMachine * TM)102 FunctionPass *llvm::createSjLjEHPreparePass(const TargetMachine *TM) {
103 return new SjLjEHPrepare(TM);
104 }
105
106 // doInitialization - Set up decalarations and types needed to process
107 // exceptions.
doInitialization(Module & M)108 bool SjLjEHPrepareImpl::doInitialization(Module &M) {
109 // Build the function context structure.
110 // builtin_setjmp uses a five word jbuf
111 Type *VoidPtrTy = PointerType::getUnqual(M.getContext());
112 unsigned DataBits =
113 TM ? TM->getSjLjDataSize() : TargetMachine::DefaultSjLjDataSize;
114 DataTy = Type::getIntNTy(M.getContext(), DataBits);
115 doubleUnderDataTy = ArrayType::get(DataTy, 4);
116 doubleUnderJBufTy = ArrayType::get(VoidPtrTy, 5);
117 FunctionContextTy = StructType::get(VoidPtrTy, // __prev
118 DataTy, // call_site
119 doubleUnderDataTy, // __data
120 VoidPtrTy, // __personality
121 VoidPtrTy, // __lsda
122 doubleUnderJBufTy // __jbuf
123 );
124
125 return false;
126 }
127
128 /// insertCallSiteStore - Insert a store of the call-site value to the
129 /// function context
insertCallSiteStore(Instruction * I,int Number)130 void SjLjEHPrepareImpl::insertCallSiteStore(Instruction *I, int Number) {
131 IRBuilder<> Builder(I);
132
133 // Get a reference to the call_site field.
134 Type *Int32Ty = Type::getInt32Ty(I->getContext());
135 Value *Zero = ConstantInt::get(Int32Ty, 0);
136 Value *One = ConstantInt::get(Int32Ty, 1);
137 Value *Idxs[2] = { Zero, One };
138 Value *CallSite =
139 Builder.CreateGEP(FunctionContextTy, FuncCtx, Idxs, "call_site");
140
141 // Insert a store of the call-site number
142 ConstantInt *CallSiteNoC = ConstantInt::get(DataTy, Number);
143 Builder.CreateStore(CallSiteNoC, CallSite, true /*volatile*/);
144 }
145
146 /// MarkBlocksLiveIn - Insert BB and all of its predecessors into LiveBBs until
147 /// we reach blocks we've already seen.
MarkBlocksLiveIn(BasicBlock * BB,SmallPtrSetImpl<BasicBlock * > & LiveBBs)148 static void MarkBlocksLiveIn(BasicBlock *BB,
149 SmallPtrSetImpl<BasicBlock *> &LiveBBs) {
150 if (!LiveBBs.insert(BB).second)
151 return; // already been here.
152
153 LiveBBs.insert_range(inverse_depth_first(BB));
154 }
155
156 /// substituteLPadValues - Substitute the values returned by the landingpad
157 /// instruction with those returned by the personality function.
substituteLPadValues(LandingPadInst * LPI,Value * ExnVal,Value * SelVal)158 void SjLjEHPrepareImpl::substituteLPadValues(LandingPadInst *LPI, Value *ExnVal,
159 Value *SelVal) {
160 SmallVector<Value *, 8> UseWorkList(LPI->users());
161 while (!UseWorkList.empty()) {
162 Value *Val = UseWorkList.pop_back_val();
163 auto *EVI = dyn_cast<ExtractValueInst>(Val);
164 if (!EVI)
165 continue;
166 if (EVI->getNumIndices() != 1)
167 continue;
168 if (*EVI->idx_begin() == 0)
169 EVI->replaceAllUsesWith(ExnVal);
170 else if (*EVI->idx_begin() == 1)
171 EVI->replaceAllUsesWith(SelVal);
172 if (EVI->use_empty())
173 EVI->eraseFromParent();
174 }
175
176 if (LPI->use_empty())
177 return;
178
179 // There are still some uses of LPI. Construct an aggregate with the exception
180 // values and replace the LPI with that aggregate.
181 Type *LPadType = LPI->getType();
182 Value *LPadVal = PoisonValue::get(LPadType);
183 auto *SelI = cast<Instruction>(SelVal);
184 IRBuilder<> Builder(SelI->getParent(), std::next(SelI->getIterator()));
185 LPadVal = Builder.CreateInsertValue(LPadVal, ExnVal, 0, "lpad.val");
186 LPadVal = Builder.CreateInsertValue(LPadVal, SelVal, 1, "lpad.val");
187
188 LPI->replaceAllUsesWith(LPadVal);
189 }
190
191 /// setupFunctionContext - Allocate the function context on the stack and fill
192 /// it with all of the data that we know at this point.
193 Value *
setupFunctionContext(Function & F,ArrayRef<LandingPadInst * > LPads)194 SjLjEHPrepareImpl::setupFunctionContext(Function &F,
195 ArrayRef<LandingPadInst *> LPads) {
196 BasicBlock *EntryBB = &F.front();
197
198 // Create an alloca for the incoming jump buffer ptr and the new jump buffer
199 // that needs to be restored on all exits from the function. This is an alloca
200 // because the value needs to be added to the global context list.
201 auto &DL = F.getDataLayout();
202 const Align Alignment = DL.getPrefTypeAlign(FunctionContextTy);
203 FuncCtx = new AllocaInst(FunctionContextTy, DL.getAllocaAddrSpace(), nullptr,
204 Alignment, "fn_context", EntryBB->begin());
205
206 // Fill in the function context structure.
207 for (LandingPadInst *LPI : LPads) {
208 IRBuilder<> Builder(LPI->getParent(),
209 LPI->getParent()->getFirstInsertionPt());
210
211 // Reference the __data field.
212 Value *FCData =
213 Builder.CreateConstGEP2_32(FunctionContextTy, FuncCtx, 0, 2, "__data");
214
215 // The exception values come back in context->__data[0].
216 Value *ExceptionAddr = Builder.CreateConstGEP2_32(doubleUnderDataTy, FCData,
217 0, 0, "exception_gep");
218 Value *ExnVal = Builder.CreateLoad(DataTy, ExceptionAddr, true, "exn_val");
219 ExnVal = Builder.CreateIntToPtr(ExnVal, Builder.getPtrTy());
220
221 Value *SelectorAddr = Builder.CreateConstGEP2_32(doubleUnderDataTy, FCData,
222 0, 1, "exn_selector_gep");
223 Value *SelVal =
224 Builder.CreateLoad(DataTy, SelectorAddr, true, "exn_selector_val");
225
226 // SelVal must be Int32Ty, so trunc it
227 SelVal = Builder.CreateTrunc(SelVal, Type::getInt32Ty(F.getContext()));
228
229 substituteLPadValues(LPI, ExnVal, SelVal);
230 }
231
232 // Personality function
233 IRBuilder<> Builder(EntryBB->getTerminator());
234 Value *PersonalityFn = F.getPersonalityFn();
235 Value *PersonalityFieldPtr = Builder.CreateConstGEP2_32(
236 FunctionContextTy, FuncCtx, 0, 3, "pers_fn_gep");
237 Builder.CreateStore(PersonalityFn, PersonalityFieldPtr, /*isVolatile=*/true);
238
239 // LSDA address
240 Value *LSDA = Builder.CreateCall(LSDAAddrFn, {}, "lsda_addr");
241 Value *LSDAFieldPtr =
242 Builder.CreateConstGEP2_32(FunctionContextTy, FuncCtx, 0, 4, "lsda_gep");
243 Builder.CreateStore(LSDA, LSDAFieldPtr, /*isVolatile=*/true);
244
245 return FuncCtx;
246 }
247
248 /// lowerIncomingArguments - To avoid having to handle incoming arguments
249 /// specially, we lower each arg to a copy instruction in the entry block. This
250 /// ensures that the argument value itself cannot be live out of the entry
251 /// block.
lowerIncomingArguments(Function & F)252 void SjLjEHPrepareImpl::lowerIncomingArguments(Function &F) {
253 BasicBlock::iterator AfterAllocaInsPt = F.begin()->begin();
254 while (isa<AllocaInst>(AfterAllocaInsPt) &&
255 cast<AllocaInst>(AfterAllocaInsPt)->isStaticAlloca())
256 ++AfterAllocaInsPt;
257 assert(AfterAllocaInsPt != F.front().end());
258
259 for (auto &AI : F.args()) {
260 // Swift error really is a register that we model as memory -- instruction
261 // selection will perform mem-to-reg for us and spill/reload appropriately
262 // around calls that clobber it. There is no need to spill this
263 // value to the stack and doing so would not be allowed.
264 if (AI.isSwiftError())
265 continue;
266
267 Type *Ty = AI.getType();
268
269 // Use 'select i8 true, %arg, poison' to simulate a 'no-op' instruction.
270 Value *TrueValue = ConstantInt::getTrue(F.getContext());
271 Value *PoisonValue = PoisonValue::get(Ty);
272 Instruction *SI = SelectInst::Create(
273 TrueValue, &AI, PoisonValue, AI.getName() + ".tmp", AfterAllocaInsPt);
274 AI.replaceAllUsesWith(SI);
275
276 // Reset the operand, because it was clobbered by the RAUW above.
277 SI->setOperand(1, &AI);
278 }
279 }
280
281 /// lowerAcrossUnwindEdges - Find all variables which are alive across an unwind
282 /// edge and spill them.
lowerAcrossUnwindEdges(Function & F,ArrayRef<InvokeInst * > Invokes)283 void SjLjEHPrepareImpl::lowerAcrossUnwindEdges(Function &F,
284 ArrayRef<InvokeInst *> Invokes) {
285 // Finally, scan the code looking for instructions with bad live ranges.
286 for (BasicBlock &BB : F) {
287 for (Instruction &Inst : BB) {
288 // Ignore obvious cases we don't have to handle. In particular, most
289 // instructions either have no uses or only have a single use inside the
290 // current block. Ignore them quickly.
291 if (Inst.use_empty())
292 continue;
293 if (Inst.hasOneUse() &&
294 cast<Instruction>(Inst.user_back())->getParent() == &BB &&
295 !isa<PHINode>(Inst.user_back()))
296 continue;
297
298 // If this is an alloca in the entry block, it's not a real register
299 // value.
300 if (auto *AI = dyn_cast<AllocaInst>(&Inst))
301 if (AI->isStaticAlloca())
302 continue;
303
304 // Avoid iterator invalidation by copying users to a temporary vector.
305 SmallVector<Instruction *, 16> Users;
306 for (User *U : Inst.users()) {
307 Instruction *UI = cast<Instruction>(U);
308 if (UI->getParent() != &BB || isa<PHINode>(UI))
309 Users.push_back(UI);
310 }
311
312 // Find all of the blocks that this value is live in.
313 SmallPtrSet<BasicBlock *, 32> LiveBBs;
314 LiveBBs.insert(&BB);
315 while (!Users.empty()) {
316 Instruction *U = Users.pop_back_val();
317
318 if (!isa<PHINode>(U)) {
319 MarkBlocksLiveIn(U->getParent(), LiveBBs);
320 } else {
321 // Uses for a PHI node occur in their predecessor block.
322 PHINode *PN = cast<PHINode>(U);
323 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
324 if (PN->getIncomingValue(i) == &Inst)
325 MarkBlocksLiveIn(PN->getIncomingBlock(i), LiveBBs);
326 }
327 }
328
329 // Now that we know all of the blocks that this thing is live in, see if
330 // it includes any of the unwind locations.
331 bool NeedsSpill = false;
332 for (InvokeInst *Invoke : Invokes) {
333 BasicBlock *UnwindBlock = Invoke->getUnwindDest();
334 if (UnwindBlock != &BB && LiveBBs.count(UnwindBlock)) {
335 LLVM_DEBUG(dbgs() << "SJLJ Spill: " << Inst << " around "
336 << UnwindBlock->getName() << "\n");
337 NeedsSpill = true;
338 break;
339 }
340 }
341
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.
346 if (NeedsSpill) {
347 DemoteRegToStack(Inst, true);
348 ++NumSpilled;
349 }
350 }
351 }
352
353 // Go through the landing pads and remove any PHIs there.
354 for (InvokeInst *Invoke : Invokes) {
355 BasicBlock *UnwindBlock = Invoke->getUnwindDest();
356 LandingPadInst *LPI = UnwindBlock->getLandingPadInst();
357
358 // Place PHIs into a set to avoid invalidating the iterator.
359 SmallPtrSet<PHINode *, 8> PHIsToDemote;
360 for (BasicBlock::iterator PN = UnwindBlock->begin(); isa<PHINode>(PN); ++PN)
361 PHIsToDemote.insert(cast<PHINode>(PN));
362 if (PHIsToDemote.empty())
363 continue;
364
365 // Demote the PHIs to the stack.
366 for (PHINode *PN : PHIsToDemote)
367 DemotePHIToStack(PN);
368
369 // Move the landingpad instruction back to the top of the landing pad block.
370 LPI->moveBefore(UnwindBlock->begin());
371 }
372 }
373
374 /// setupEntryBlockAndCallSites - Setup the entry block by creating and filling
375 /// the function context and marking the call sites with the appropriate
376 /// values. These values are used by the DWARF EH emitter.
setupEntryBlockAndCallSites(Function & F)377 bool SjLjEHPrepareImpl::setupEntryBlockAndCallSites(Function &F) {
378 SmallVector<ReturnInst *, 16> Returns;
379 SmallVector<InvokeInst *, 16> Invokes;
380 SmallSetVector<LandingPadInst *, 16> LPads;
381
382 // Look through the terminators of the basic blocks to find invokes.
383 for (BasicBlock &BB : F)
384 if (auto *II = dyn_cast<InvokeInst>(BB.getTerminator())) {
385 if (Function *Callee = II->getCalledFunction())
386 if (Callee->getIntrinsicID() == Intrinsic::donothing) {
387 // Remove the NOP invoke.
388 BranchInst::Create(II->getNormalDest(), II->getIterator());
389 II->eraseFromParent();
390 continue;
391 }
392
393 Invokes.push_back(II);
394 LPads.insert(II->getUnwindDest()->getLandingPadInst());
395 } else if (auto *RI = dyn_cast<ReturnInst>(BB.getTerminator())) {
396 Returns.push_back(RI);
397 }
398
399 if (Invokes.empty())
400 return false;
401
402 NumInvokes += Invokes.size();
403
404 lowerIncomingArguments(F);
405 lowerAcrossUnwindEdges(F, Invokes);
406
407 Value *FuncCtx =
408 setupFunctionContext(F, ArrayRef(LPads.begin(), LPads.end()));
409 BasicBlock *EntryBB = &F.front();
410 IRBuilder<> Builder(EntryBB->getTerminator());
411
412 // Get a reference to the jump buffer.
413 Value *JBufPtr =
414 Builder.CreateConstGEP2_32(FunctionContextTy, FuncCtx, 0, 5, "jbuf_gep");
415
416 // Save the frame pointer.
417 Value *FramePtr = Builder.CreateConstGEP2_32(doubleUnderJBufTy, JBufPtr, 0, 0,
418 "jbuf_fp_gep");
419
420 Value *Val = Builder.CreateCall(FrameAddrFn, Builder.getInt32(0), "fp");
421 Builder.CreateStore(Val, FramePtr, /*isVolatile=*/true);
422
423 // Save the stack pointer.
424 Value *StackPtr = Builder.CreateConstGEP2_32(doubleUnderJBufTy, JBufPtr, 0, 2,
425 "jbuf_sp_gep");
426
427 Val = Builder.CreateCall(StackAddrFn, {}, "sp");
428 Builder.CreateStore(Val, StackPtr, /*isVolatile=*/true);
429
430 // Call the setup_dispatch intrinsic. It fills in the rest of the jmpbuf.
431 Builder.CreateCall(BuiltinSetupDispatchFn, {});
432
433 // Store a pointer to the function context so that the back-end will know
434 // where to look for it.
435 Builder.CreateCall(FuncCtxFn, FuncCtx);
436
437 // Register the function context and make sure it's known to not throw.
438 CallInst *Register = Builder.CreateCall(RegisterFn, FuncCtx, "");
439 Register->setDoesNotThrow();
440
441 // At this point, we are all set up, update the invoke instructions to mark
442 // their call_site values.
443 for (unsigned I = 0, E = Invokes.size(); I != E; ++I) {
444 insertCallSiteStore(Invokes[I], I + 1);
445
446 ConstantInt *CallSiteNum =
447 ConstantInt::get(Type::getInt32Ty(F.getContext()), I + 1);
448
449 // Record the call site value for the back end so it stays associated with
450 // the invoke.
451 CallInst::Create(CallSiteFn, CallSiteNum, "", Invokes[I]->getIterator());
452 }
453
454 // Mark call instructions that aren't nounwind as no-action (call_site ==
455 // -1). Skip the entry block, as prior to then, no function context has been
456 // created for this function and any unexpected exceptions thrown will go
457 // directly to the caller's context, which is what we want anyway, so no need
458 // to do anything here.
459 for (BasicBlock &BB : F) {
460 if (&BB == &F.front())
461 continue;
462 for (Instruction &I : BB)
463 if (!isa<InvokeInst>(I) && I.mayThrow())
464 insertCallSiteStore(&I, -1);
465 }
466
467 // Following any allocas not in the entry block, update the saved SP in the
468 // jmpbuf to the new value.
469 for (BasicBlock &BB : F) {
470 if (&BB == &F.front())
471 continue;
472 for (Instruction &I : BB) {
473 if (auto *CI = dyn_cast<CallInst>(&I)) {
474 if (CI->getCalledFunction() != StackRestoreFn)
475 continue;
476 } else if (!isa<AllocaInst>(&I)) {
477 continue;
478 }
479 Instruction *StackAddr = CallInst::Create(StackAddrFn, "sp");
480 StackAddr->insertAfter(I.getIterator());
481 new StoreInst(StackAddr, StackPtr, true,
482 std::next(StackAddr->getIterator()));
483 }
484 }
485
486 // Finally, for any returns from this function, if this function contains an
487 // invoke, add a call to unregister the function context.
488 for (ReturnInst *Return : Returns) {
489 Instruction *InsertPoint = Return;
490 if (CallInst *CI = Return->getParent()->getTerminatingMustTailCall())
491 InsertPoint = CI;
492 CallInst::Create(UnregisterFn, FuncCtx, "", InsertPoint->getIterator());
493 }
494
495 return true;
496 }
497
runOnFunction(Function & F)498 bool SjLjEHPrepareImpl::runOnFunction(Function &F) {
499 Module &M = *F.getParent();
500 RegisterFn = M.getOrInsertFunction(
501 "_Unwind_SjLj_Register", Type::getVoidTy(M.getContext()),
502 PointerType::getUnqual(FunctionContextTy->getContext()));
503 UnregisterFn = M.getOrInsertFunction(
504 "_Unwind_SjLj_Unregister", Type::getVoidTy(M.getContext()),
505 PointerType::getUnqual(FunctionContextTy->getContext()));
506
507 PointerType *AllocaPtrTy = M.getDataLayout().getAllocaPtrType(M.getContext());
508
509 FrameAddrFn = Intrinsic::getOrInsertDeclaration(&M, Intrinsic::frameaddress,
510 {AllocaPtrTy});
511 StackAddrFn = Intrinsic::getOrInsertDeclaration(&M, Intrinsic::stacksave,
512 {AllocaPtrTy});
513 StackRestoreFn = Intrinsic::getOrInsertDeclaration(
514 &M, Intrinsic::stackrestore, {AllocaPtrTy});
515 BuiltinSetupDispatchFn =
516 Intrinsic::getOrInsertDeclaration(&M, Intrinsic::eh_sjlj_setup_dispatch);
517 LSDAAddrFn = Intrinsic::getOrInsertDeclaration(&M, Intrinsic::eh_sjlj_lsda);
518 CallSiteFn =
519 Intrinsic::getOrInsertDeclaration(&M, Intrinsic::eh_sjlj_callsite);
520 FuncCtxFn =
521 Intrinsic::getOrInsertDeclaration(&M, Intrinsic::eh_sjlj_functioncontext);
522
523 bool Res = setupEntryBlockAndCallSites(F);
524 return Res;
525 }
526