llvm.org GIT mirror llvm / release_80 lib / Target / X86 / X86WinEHState.cpp
release_80

Tree @release_80 (Download .tar.gz)

X86WinEHState.cpp @release_80raw · history · blame

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
//===-- X86WinEHState - Insert EH state updates for win32 exceptions ------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// All functions using an MSVC EH personality use an explicitly updated state
// number stored in an exception registration stack object. The registration
// object is linked into a thread-local chain of registrations stored at fs:00.
// This pass adds the registration object and EH state updates.
//
//===----------------------------------------------------------------------===//

#include "X86.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/EHPersonalities.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/WinEHFuncInfo.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/Debug.h"
#include <deque>

using namespace llvm;

#define DEBUG_TYPE "winehstate"

namespace {
const int OverdefinedState = INT_MIN;

class WinEHStatePass : public FunctionPass {
public:
  static char ID; // Pass identification, replacement for typeid.

  WinEHStatePass() : FunctionPass(ID) {
    initializeWinEHStatePassPass(*PassRegistry::getPassRegistry());
  }

  bool runOnFunction(Function &Fn) override;

  bool doInitialization(Module &M) override;

  bool doFinalization(Module &M) override;

  void getAnalysisUsage(AnalysisUsage &AU) const override;

  StringRef getPassName() const override {
    return "Windows 32-bit x86 EH state insertion";
  }

private:
  void emitExceptionRegistrationRecord(Function *F);

  void linkExceptionRegistration(IRBuilder<> &Builder, Function *Handler);
  void unlinkExceptionRegistration(IRBuilder<> &Builder);
  void addStateStores(Function &F, WinEHFuncInfo &FuncInfo);
  void insertStateNumberStore(Instruction *IP, int State);

  Value *emitEHLSDA(IRBuilder<> &Builder, Function *F);

  Function *generateLSDAInEAXThunk(Function *ParentFunc);

  bool isStateStoreNeeded(EHPersonality Personality, CallSite CS);
  void rewriteSetJmpCallSite(IRBuilder<> &Builder, Function &F, CallSite CS,
                             Value *State);
  int getBaseStateForBB(DenseMap<BasicBlock *, ColorVector> &BlockColors,
                        WinEHFuncInfo &FuncInfo, BasicBlock *BB);
  int getStateForCallSite(DenseMap<BasicBlock *, ColorVector> &BlockColors,
                          WinEHFuncInfo &FuncInfo, CallSite CS);

  // Module-level type getters.
  Type *getEHLinkRegistrationType();
  Type *getSEHRegistrationType();
  Type *getCXXEHRegistrationType();

  // Per-module data.
  Module *TheModule = nullptr;
  StructType *EHLinkRegistrationTy = nullptr;
  StructType *CXXEHRegistrationTy = nullptr;
  StructType *SEHRegistrationTy = nullptr;
  Constant *SetJmp3 = nullptr;
  Constant *CxxLongjmpUnwind = nullptr;

  // Per-function state
  EHPersonality Personality = EHPersonality::Unknown;
  Function *PersonalityFn = nullptr;
  bool UseStackGuard = false;
  int ParentBaseState;
  Constant *SehLongjmpUnwind = nullptr;
  Constant *Cookie = nullptr;

  /// The stack allocation containing all EH data, including the link in the
  /// fs:00 chain and the current state.
  AllocaInst *RegNode = nullptr;

  // The allocation containing the EH security guard.
  AllocaInst *EHGuardNode = nullptr;

  /// The index of the state field of RegNode.
  int StateFieldIndex = ~0U;

  /// The linked list node subobject inside of RegNode.
  Value *Link = nullptr;
};
}

FunctionPass *llvm::createX86WinEHStatePass() { return new WinEHStatePass(); }

char WinEHStatePass::ID = 0;

INITIALIZE_PASS(WinEHStatePass, "x86-winehstate",
                "Insert stores for EH state numbers", false, false)

bool WinEHStatePass::doInitialization(Module &M) {
  TheModule = &M;
  return false;
}

bool WinEHStatePass::doFinalization(Module &M) {
  assert(TheModule == &M);
  TheModule = nullptr;
  EHLinkRegistrationTy = nullptr;
  CXXEHRegistrationTy = nullptr;
  SEHRegistrationTy = nullptr;
  SetJmp3 = nullptr;
  CxxLongjmpUnwind = nullptr;
  SehLongjmpUnwind = nullptr;
  Cookie = nullptr;
  return false;
}

void WinEHStatePass::getAnalysisUsage(AnalysisUsage &AU) const {
  // This pass should only insert a stack allocation, memory accesses, and
  // localrecovers.
  AU.setPreservesCFG();
}

bool WinEHStatePass::runOnFunction(Function &F) {
  // Don't insert state stores or exception handler thunks for
  // available_externally functions. The handler needs to reference the LSDA,
  // which will not be emitted in this case.
  if (F.hasAvailableExternallyLinkage())
    return false;

  // Check the personality. Do nothing if this personality doesn't use funclets.
  if (!F.hasPersonalityFn())
    return false;
  PersonalityFn =
      dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts());
  if (!PersonalityFn)
    return false;
  Personality = classifyEHPersonality(PersonalityFn);
  if (!isFuncletEHPersonality(Personality))
    return false;

  // Skip this function if there are no EH pads and we aren't using IR-level
  // outlining.
  bool HasPads = false;
  for (BasicBlock &BB : F) {
    if (BB.isEHPad()) {
      HasPads = true;
      break;
    }
  }
  if (!HasPads)
    return false;

  Type *Int8PtrType = Type::getInt8PtrTy(TheModule->getContext());
  SetJmp3 = TheModule->getOrInsertFunction(
      "_setjmp3", FunctionType::get(
                      Type::getInt32Ty(TheModule->getContext()),
                      {Int8PtrType, Type::getInt32Ty(TheModule->getContext())},
                      /*isVarArg=*/true));

  // Disable frame pointer elimination in this function.
  // FIXME: Do the nested handlers need to keep the parent ebp in ebp, or can we
  // use an arbitrary register?
  F.addFnAttr("no-frame-pointer-elim", "true");

  emitExceptionRegistrationRecord(&F);

  // The state numbers calculated here in IR must agree with what we calculate
  // later on for the MachineFunction. In particular, if an IR pass deletes an
  // unreachable EH pad after this point before machine CFG construction, we
  // will be in trouble. If this assumption is ever broken, we should turn the
  // numbers into an immutable analysis pass.
  WinEHFuncInfo FuncInfo;
  addStateStores(F, FuncInfo);

  // Reset per-function state.
  PersonalityFn = nullptr;
  Personality = EHPersonality::Unknown;
  UseStackGuard = false;
  RegNode = nullptr;
  EHGuardNode = nullptr;

  return true;
}

/// Get the common EH registration subobject:
///   typedef _EXCEPTION_DISPOSITION (*PEXCEPTION_ROUTINE)(
///       _EXCEPTION_RECORD *, void *, _CONTEXT *, void *);
///   struct EHRegistrationNode {
///     EHRegistrationNode *Next;
///     PEXCEPTION_ROUTINE Handler;
///   };
Type *WinEHStatePass::getEHLinkRegistrationType() {
  if (EHLinkRegistrationTy)
    return EHLinkRegistrationTy;
  LLVMContext &Context = TheModule->getContext();
  EHLinkRegistrationTy = StructType::create(Context, "EHRegistrationNode");
  Type *FieldTys[] = {
      EHLinkRegistrationTy->getPointerTo(0), // EHRegistrationNode *Next
      Type::getInt8PtrTy(Context) // EXCEPTION_DISPOSITION (*Handler)(...)
  };
  EHLinkRegistrationTy->setBody(FieldTys, false);
  return EHLinkRegistrationTy;
}

/// The __CxxFrameHandler3 registration node:
///   struct CXXExceptionRegistration {
///     void *SavedESP;
///     EHRegistrationNode SubRecord;
///     int32_t TryLevel;
///   };
Type *WinEHStatePass::getCXXEHRegistrationType() {
  if (CXXEHRegistrationTy)
    return CXXEHRegistrationTy;
  LLVMContext &Context = TheModule->getContext();
  Type *FieldTys[] = {
      Type::getInt8PtrTy(Context), // void *SavedESP
      getEHLinkRegistrationType(), // EHRegistrationNode SubRecord
      Type::getInt32Ty(Context)    // int32_t TryLevel
  };
  CXXEHRegistrationTy =
      StructType::create(FieldTys, "CXXExceptionRegistration");
  return CXXEHRegistrationTy;
}

/// The _except_handler3/4 registration node:
///   struct EH4ExceptionRegistration {
///     void *SavedESP;
///     _EXCEPTION_POINTERS *ExceptionPointers;
///     EHRegistrationNode SubRecord;
///     int32_t EncodedScopeTable;
///     int32_t TryLevel;
///   };
Type *WinEHStatePass::getSEHRegistrationType() {
  if (SEHRegistrationTy)
    return SEHRegistrationTy;
  LLVMContext &Context = TheModule->getContext();
  Type *FieldTys[] = {
      Type::getInt8PtrTy(Context), // void *SavedESP
      Type::getInt8PtrTy(Context), // void *ExceptionPointers
      getEHLinkRegistrationType(), // EHRegistrationNode SubRecord
      Type::getInt32Ty(Context),   // int32_t EncodedScopeTable
      Type::getInt32Ty(Context)    // int32_t TryLevel
  };
  SEHRegistrationTy = StructType::create(FieldTys, "SEHExceptionRegistration");
  return SEHRegistrationTy;
}

// Emit an exception registration record. These are stack allocations with the
// common subobject of two pointers: the previous registration record (the old
// fs:00) and the personality function for the current frame. The data before
// and after that is personality function specific.
void WinEHStatePass::emitExceptionRegistrationRecord(Function *F) {
  assert(Personality == EHPersonality::MSVC_CXX ||
         Personality == EHPersonality::MSVC_X86SEH);

  // Struct type of RegNode. Used for GEPing.
  Type *RegNodeTy;

  IRBuilder<> Builder(&F->getEntryBlock(), F->getEntryBlock().begin());
  Type *Int8PtrType = Builder.getInt8PtrTy();
  Type *Int32Ty = Builder.getInt32Ty();
  Type *VoidTy = Builder.getVoidTy();

  if (Personality == EHPersonality::MSVC_CXX) {
    RegNodeTy = getCXXEHRegistrationType();
    RegNode = Builder.CreateAlloca(RegNodeTy);
    // SavedESP = llvm.stacksave()
    Value *SP = Builder.CreateCall(
        Intrinsic::getDeclaration(TheModule, Intrinsic::stacksave), {});
    Builder.CreateStore(SP, Builder.CreateStructGEP(RegNodeTy, RegNode, 0));
    // TryLevel = -1
    StateFieldIndex = 2;
    ParentBaseState = -1;
    insertStateNumberStore(&*Builder.GetInsertPoint(), ParentBaseState);
    // Handler = __ehhandler$F
    Function *Trampoline = generateLSDAInEAXThunk(F);
    Link = Builder.CreateStructGEP(RegNodeTy, RegNode, 1);
    linkExceptionRegistration(Builder, Trampoline);

    CxxLongjmpUnwind = TheModule->getOrInsertFunction(
        "__CxxLongjmpUnwind",
        FunctionType::get(VoidTy, Int8PtrType, /*isVarArg=*/false));
    cast<Function>(CxxLongjmpUnwind->stripPointerCasts())
        ->setCallingConv(CallingConv::X86_StdCall);
  } else if (Personality == EHPersonality::MSVC_X86SEH) {
    // If _except_handler4 is in use, some additional guard checks and prologue
    // stuff is required.
    StringRef PersonalityName = PersonalityFn->getName();
    UseStackGuard = (PersonalityName == "_except_handler4");

    // Allocate local structures.
    RegNodeTy = getSEHRegistrationType();
    RegNode = Builder.CreateAlloca(RegNodeTy);
    if (UseStackGuard)
      EHGuardNode = Builder.CreateAlloca(Int32Ty);

    // SavedESP = llvm.stacksave()
    Value *SP = Builder.CreateCall(
        Intrinsic::getDeclaration(TheModule, Intrinsic::stacksave), {});
    Builder.CreateStore(SP, Builder.CreateStructGEP(RegNodeTy, RegNode, 0));
    // TryLevel = -2 / -1
    StateFieldIndex = 4;
    ParentBaseState = UseStackGuard ? -2 : -1;
    insertStateNumberStore(&*Builder.GetInsertPoint(), ParentBaseState);
    // ScopeTable = llvm.x86.seh.lsda(F)
    Value *LSDA = emitEHLSDA(Builder, F);
    LSDA = Builder.CreatePtrToInt(LSDA, Int32Ty);
    // If using _except_handler4, xor the address of the table with
    // __security_cookie.
    if (UseStackGuard) {
      Cookie = TheModule->getOrInsertGlobal("__security_cookie", Int32Ty);
      Value *Val = Builder.CreateLoad(Int32Ty, Cookie, "cookie");
      LSDA = Builder.CreateXor(LSDA, Val);
    }
    Builder.CreateStore(LSDA, Builder.CreateStructGEP(RegNodeTy, RegNode, 3));

    // If using _except_handler4, the EHGuard contains: FramePtr xor Cookie.
    if (UseStackGuard) {
      Value *Val = Builder.CreateLoad(Int32Ty, Cookie);
      Value *FrameAddr = Builder.CreateCall(
          Intrinsic::getDeclaration(TheModule, Intrinsic::frameaddress),
          Builder.getInt32(0), "frameaddr");
      Value *FrameAddrI32 = Builder.CreatePtrToInt(FrameAddr, Int32Ty);
      FrameAddrI32 = Builder.CreateXor(FrameAddrI32, Val);
      Builder.CreateStore(FrameAddrI32, EHGuardNode);
    }

    // Register the exception handler.
    Link = Builder.CreateStructGEP(RegNodeTy, RegNode, 2);
    linkExceptionRegistration(Builder, PersonalityFn);

    SehLongjmpUnwind = TheModule->getOrInsertFunction(
        UseStackGuard ? "_seh_longjmp_unwind4" : "_seh_longjmp_unwind",
        FunctionType::get(Type::getVoidTy(TheModule->getContext()), Int8PtrType,
                          /*isVarArg=*/false));
    cast<Function>(SehLongjmpUnwind->stripPointerCasts())
        ->setCallingConv(CallingConv::X86_StdCall);
  } else {
    llvm_unreachable("unexpected personality function");
  }

  // Insert an unlink before all returns.
  for (BasicBlock &BB : *F) {
    Instruction *T = BB.getTerminator();
    if (!isa<ReturnInst>(T))
      continue;
    Builder.SetInsertPoint(T);
    unlinkExceptionRegistration(Builder);
  }
}

Value *WinEHStatePass::emitEHLSDA(IRBuilder<> &Builder, Function *F) {
  Value *FI8 = Builder.CreateBitCast(F, Type::getInt8PtrTy(F->getContext()));
  return Builder.CreateCall(
      Intrinsic::getDeclaration(TheModule, Intrinsic::x86_seh_lsda), FI8);
}

/// Generate a thunk that puts the LSDA of ParentFunc in EAX and then calls
/// PersonalityFn, forwarding the parameters passed to PEXCEPTION_ROUTINE:
///   typedef _EXCEPTION_DISPOSITION (*PEXCEPTION_ROUTINE)(
///       _EXCEPTION_RECORD *, void *, _CONTEXT *, void *);
/// We essentially want this code:
///   movl $lsda, %eax
///   jmpl ___CxxFrameHandler3
Function *WinEHStatePass::generateLSDAInEAXThunk(Function *ParentFunc) {
  LLVMContext &Context = ParentFunc->getContext();
  Type *Int32Ty = Type::getInt32Ty(Context);
  Type *Int8PtrType = Type::getInt8PtrTy(Context);
  Type *ArgTys[5] = {Int8PtrType, Int8PtrType, Int8PtrType, Int8PtrType,
                     Int8PtrType};
  FunctionType *TrampolineTy =
      FunctionType::get(Int32Ty, makeArrayRef(&ArgTys[0], 4),
                        /*isVarArg=*/false);
  FunctionType *TargetFuncTy =
      FunctionType::get(Int32Ty, makeArrayRef(&ArgTys[0], 5),
                        /*isVarArg=*/false);
  Function *Trampoline =
      Function::Create(TrampolineTy, GlobalValue::InternalLinkage,
                       Twine("__ehhandler$") + GlobalValue::dropLLVMManglingEscape(
                                                   ParentFunc->getName()),
                       TheModule);
  if (auto *C = ParentFunc->getComdat())
    Trampoline->setComdat(C);
  BasicBlock *EntryBB = BasicBlock::Create(Context, "entry", Trampoline);
  IRBuilder<> Builder(EntryBB);
  Value *LSDA = emitEHLSDA(Builder, ParentFunc);
  Value *CastPersonality =
      Builder.CreateBitCast(PersonalityFn, TargetFuncTy->getPointerTo());
  auto AI = Trampoline->arg_begin();
  Value *Args[5] = {LSDA, &*AI++, &*AI++, &*AI++, &*AI++};
  CallInst *Call = Builder.CreateCall(CastPersonality, Args);
  // Can't use musttail due to prototype mismatch, but we can use tail.
  Call->setTailCall(true);
  // Set inreg so we pass it in EAX.
  Call->addParamAttr(0, Attribute::InReg);
  Builder.CreateRet(Call);
  return Trampoline;
}

void WinEHStatePass::linkExceptionRegistration(IRBuilder<> &Builder,
                                               Function *Handler) {
  // Emit the .safeseh directive for this function.
  Handler->addFnAttr("safeseh");

  Type *LinkTy = getEHLinkRegistrationType();
  // Handler = Handler
  Value *HandlerI8 = Builder.CreateBitCast(Handler, Builder.getInt8PtrTy());
  Builder.CreateStore(HandlerI8, Builder.CreateStructGEP(LinkTy, Link, 1));
  // Next = [fs:00]
  Constant *FSZero =
      Constant::getNullValue(LinkTy->getPointerTo()->getPointerTo(257));
  Value *Next = Builder.CreateLoad(FSZero);
  Builder.CreateStore(Next, Builder.CreateStructGEP(LinkTy, Link, 0));
  // [fs:00] = Link
  Builder.CreateStore(Link, FSZero);
}

void WinEHStatePass::unlinkExceptionRegistration(IRBuilder<> &Builder) {
  // Clone Link into the current BB for better address mode folding.
  if (auto *GEP = dyn_cast<GetElementPtrInst>(Link)) {
    GEP = cast<GetElementPtrInst>(GEP->clone());
    Builder.Insert(GEP);
    Link = GEP;
  }
  Type *LinkTy = getEHLinkRegistrationType();
  // [fs:00] = Link->Next
  Value *Next =
      Builder.CreateLoad(Builder.CreateStructGEP(LinkTy, Link, 0));
  Constant *FSZero =
      Constant::getNullValue(LinkTy->getPointerTo()->getPointerTo(257));
  Builder.CreateStore(Next, FSZero);
}

// Calls to setjmp(p) are lowered to _setjmp3(p, 0) by the frontend.
// The idea behind _setjmp3 is that it takes an optional number of personality
// specific parameters to indicate how to restore the personality-specific frame
// state when longjmp is initiated.  Typically, the current TryLevel is saved.
void WinEHStatePass::rewriteSetJmpCallSite(IRBuilder<> &Builder, Function &F,
                                           CallSite CS, Value *State) {
  // Don't rewrite calls with a weird number of arguments.
  if (CS.getNumArgOperands() != 2)
    return;

  Instruction *Inst = CS.getInstruction();

  SmallVector<OperandBundleDef, 1> OpBundles;
  CS.getOperandBundlesAsDefs(OpBundles);

  SmallVector<Value *, 3> OptionalArgs;
  if (Personality == EHPersonality::MSVC_CXX) {
    OptionalArgs.push_back(CxxLongjmpUnwind);
    OptionalArgs.push_back(State);
    OptionalArgs.push_back(emitEHLSDA(Builder, &F));
  } else if (Personality == EHPersonality::MSVC_X86SEH) {
    OptionalArgs.push_back(SehLongjmpUnwind);
    OptionalArgs.push_back(State);
    if (UseStackGuard)
      OptionalArgs.push_back(Cookie);
  } else {
    llvm_unreachable("unhandled personality!");
  }

  SmallVector<Value *, 5> Args;
  Args.push_back(
      Builder.CreateBitCast(CS.getArgOperand(0), Builder.getInt8PtrTy()));
  Args.push_back(Builder.getInt32(OptionalArgs.size()));
  Args.append(OptionalArgs.begin(), OptionalArgs.end());

  CallSite NewCS;
  if (CS.isCall()) {
    auto *CI = cast<CallInst>(Inst);
    CallInst *NewCI = Builder.CreateCall(SetJmp3, Args, OpBundles);
    NewCI->setTailCallKind(CI->getTailCallKind());
    NewCS = NewCI;
  } else {
    auto *II = cast<InvokeInst>(Inst);
    NewCS = Builder.CreateInvoke(
        SetJmp3, II->getNormalDest(), II->getUnwindDest(), Args, OpBundles);
  }
  NewCS.setCallingConv(CS.getCallingConv());
  NewCS.setAttributes(CS.getAttributes());
  NewCS->setDebugLoc(CS->getDebugLoc());

  Instruction *NewInst = NewCS.getInstruction();
  NewInst->takeName(Inst);
  Inst->replaceAllUsesWith(NewInst);
  Inst->eraseFromParent();
}

// Figure out what state we should assign calls in this block.
int WinEHStatePass::getBaseStateForBB(
    DenseMap<BasicBlock *, ColorVector> &BlockColors, WinEHFuncInfo &FuncInfo,
    BasicBlock *BB) {
  int BaseState = ParentBaseState;
  auto &BBColors = BlockColors[BB];

  assert(BBColors.size() == 1 && "multi-color BB not removed by preparation");
  BasicBlock *FuncletEntryBB = BBColors.front();
  if (auto *FuncletPad =
          dyn_cast<FuncletPadInst>(FuncletEntryBB->getFirstNonPHI())) {
    auto BaseStateI = FuncInfo.FuncletBaseStateMap.find(FuncletPad);
    if (BaseStateI != FuncInfo.FuncletBaseStateMap.end())
      BaseState = BaseStateI->second;
  }

  return BaseState;
}

// Calculate the state a call-site is in.
int WinEHStatePass::getStateForCallSite(
    DenseMap<BasicBlock *, ColorVector> &BlockColors, WinEHFuncInfo &FuncInfo,
    CallSite CS) {
  if (auto *II = dyn_cast<InvokeInst>(CS.getInstruction())) {
    // Look up the state number of the EH pad this unwinds to.
    assert(FuncInfo.InvokeStateMap.count(II) && "invoke has no state!");
    return FuncInfo.InvokeStateMap[II];
  }
  // Possibly throwing call instructions have no actions to take after
  // an unwind. Ensure they are in the -1 state.
  return getBaseStateForBB(BlockColors, FuncInfo, CS.getParent());
}

// Calculate the intersection of all the FinalStates for a BasicBlock's
// predecessors.
static int getPredState(DenseMap<BasicBlock *, int> &FinalStates, Function &F,
                        int ParentBaseState, BasicBlock *BB) {
  // The entry block has no predecessors but we know that the prologue always
  // sets us up with a fixed state.
  if (&F.getEntryBlock() == BB)
    return ParentBaseState;

  // This is an EH Pad, conservatively report this basic block as overdefined.
  if (BB->isEHPad())
    return OverdefinedState;

  int CommonState = OverdefinedState;
  for (BasicBlock *PredBB : predecessors(BB)) {
    // We didn't manage to get a state for one of these predecessors,
    // conservatively report this basic block as overdefined.
    auto PredEndState = FinalStates.find(PredBB);
    if (PredEndState == FinalStates.end())
      return OverdefinedState;

    // This code is reachable via exceptional control flow,
    // conservatively report this basic block as overdefined.
    if (isa<CatchReturnInst>(PredBB->getTerminator()))
      return OverdefinedState;

    int PredState = PredEndState->second;
    assert(PredState != OverdefinedState &&
           "overdefined BBs shouldn't be in FinalStates");
    if (CommonState == OverdefinedState)
      CommonState = PredState;

    // At least two predecessors have different FinalStates,
    // conservatively report this basic block as overdefined.
    if (CommonState != PredState)
      return OverdefinedState;
  }

  return CommonState;
}

// Calculate the intersection of all the InitialStates for a BasicBlock's
// successors.
static int getSuccState(DenseMap<BasicBlock *, int> &InitialStates, Function &F,
                        int ParentBaseState, BasicBlock *BB) {
  // This block rejoins normal control flow,
  // conservatively report this basic block as overdefined.
  if (isa<CatchReturnInst>(BB->getTerminator()))
    return OverdefinedState;

  int CommonState = OverdefinedState;
  for (BasicBlock *SuccBB : successors(BB)) {
    // We didn't manage to get a state for one of these predecessors,
    // conservatively report this basic block as overdefined.
    auto SuccStartState = InitialStates.find(SuccBB);
    if (SuccStartState == InitialStates.end())
      return OverdefinedState;

    // This is an EH Pad, conservatively report this basic block as overdefined.
    if (SuccBB->isEHPad())
      return OverdefinedState;

    int SuccState = SuccStartState->second;
    assert(SuccState != OverdefinedState &&
           "overdefined BBs shouldn't be in FinalStates");
    if (CommonState == OverdefinedState)
      CommonState = SuccState;

    // At least two successors have different InitialStates,
    // conservatively report this basic block as overdefined.
    if (CommonState != SuccState)
      return OverdefinedState;
  }

  return CommonState;
}

bool WinEHStatePass::isStateStoreNeeded(EHPersonality Personality,
                                        CallSite CS) {
  if (!CS)
    return false;

  // If the function touches memory, it needs a state store.
  if (isAsynchronousEHPersonality(Personality))
    return !CS.doesNotAccessMemory();

  // If the function throws, it needs a state store.
  return !CS.doesNotThrow();
}

void WinEHStatePass::addStateStores(Function &F, WinEHFuncInfo &FuncInfo) {
  // Mark the registration node. The backend needs to know which alloca it is so
  // that it can recover the original frame pointer.
  IRBuilder<> Builder(RegNode->getNextNode());
  Value *RegNodeI8 = Builder.CreateBitCast(RegNode, Builder.getInt8PtrTy());
  Builder.CreateCall(
      Intrinsic::getDeclaration(TheModule, Intrinsic::x86_seh_ehregnode),
      {RegNodeI8});

  if (EHGuardNode) {
    IRBuilder<> Builder(EHGuardNode->getNextNode());
    Value *EHGuardNodeI8 =
        Builder.CreateBitCast(EHGuardNode, Builder.getInt8PtrTy());
    Builder.CreateCall(
        Intrinsic::getDeclaration(TheModule, Intrinsic::x86_seh_ehguard),
        {EHGuardNodeI8});
  }

  // Calculate state numbers.
  if (isAsynchronousEHPersonality(Personality))
    calculateSEHStateNumbers(&F, FuncInfo);
  else
    calculateWinCXXEHStateNumbers(&F, FuncInfo);

  // Iterate all the instructions and emit state number stores.
  DenseMap<BasicBlock *, ColorVector> BlockColors = colorEHFunclets(F);
  ReversePostOrderTraversal<Function *> RPOT(&F);

  // InitialStates yields the state of the first call-site for a BasicBlock.
  DenseMap<BasicBlock *, int> InitialStates;
  // FinalStates yields the state of the last call-site for a BasicBlock.
  DenseMap<BasicBlock *, int> FinalStates;
  // Worklist used to revisit BasicBlocks with indeterminate
  // Initial/Final-States.
  std::deque<BasicBlock *> Worklist;
  // Fill in InitialStates and FinalStates for BasicBlocks with call-sites.
  for (BasicBlock *BB : RPOT) {
    int InitialState = OverdefinedState;
    int FinalState;
    if (&F.getEntryBlock() == BB)
      InitialState = FinalState = ParentBaseState;
    for (Instruction &I : *BB) {
      CallSite CS(&I);
      if (!isStateStoreNeeded(Personality, CS))
        continue;

      int State = getStateForCallSite(BlockColors, FuncInfo, CS);
      if (InitialState == OverdefinedState)
        InitialState = State;
      FinalState = State;
    }
    // No call-sites in this basic block? That's OK, we will come back to these
    // in a later pass.
    if (InitialState == OverdefinedState) {
      Worklist.push_back(BB);
      continue;
    }
    LLVM_DEBUG(dbgs() << "X86WinEHState: " << BB->getName()
                      << " InitialState=" << InitialState << '\n');
    LLVM_DEBUG(dbgs() << "X86WinEHState: " << BB->getName()
                      << " FinalState=" << FinalState << '\n');
    InitialStates.insert({BB, InitialState});
    FinalStates.insert({BB, FinalState});
  }

  // Try to fill-in InitialStates and FinalStates which have no call-sites.
  while (!Worklist.empty()) {
    BasicBlock *BB = Worklist.front();
    Worklist.pop_front();
    // This BasicBlock has already been figured out, nothing more we can do.
    if (InitialStates.count(BB) != 0)
      continue;

    int PredState = getPredState(FinalStates, F, ParentBaseState, BB);
    if (PredState == OverdefinedState)
      continue;

    // We successfully inferred this BasicBlock's state via it's predecessors;
    // enqueue it's successors to see if we can infer their states.
    InitialStates.insert({BB, PredState});
    FinalStates.insert({BB, PredState});
    for (BasicBlock *SuccBB : successors(BB))
      Worklist.push_back(SuccBB);
  }

  // Try to hoist stores from successors.
  for (BasicBlock *BB : RPOT) {
    int SuccState = getSuccState(InitialStates, F, ParentBaseState, BB);
    if (SuccState == OverdefinedState)
      continue;

    // Update our FinalState to reflect the common InitialState of our
    // successors.
    FinalStates.insert({BB, SuccState});
  }

  // Finally, insert state stores before call-sites which transition us to a new
  // state.
  for (BasicBlock *BB : RPOT) {
    auto &BBColors = BlockColors[BB];
    BasicBlock *FuncletEntryBB = BBColors.front();
    if (isa<CleanupPadInst>(FuncletEntryBB->getFirstNonPHI()))
      continue;

    int PrevState = getPredState(FinalStates, F, ParentBaseState, BB);
    LLVM_DEBUG(dbgs() << "X86WinEHState: " << BB->getName()
                      << " PrevState=" << PrevState << '\n');

    for (Instruction &I : *BB) {
      CallSite CS(&I);
      if (!isStateStoreNeeded(Personality, CS))
        continue;

      int State = getStateForCallSite(BlockColors, FuncInfo, CS);
      if (State != PrevState)
        insertStateNumberStore(&I, State);
      PrevState = State;
    }

    // We might have hoisted a state store into this block, emit it now.
    auto EndState = FinalStates.find(BB);
    if (EndState != FinalStates.end())
      if (EndState->second != PrevState)
        insertStateNumberStore(BB->getTerminator(), EndState->second);
  }

  SmallVector<CallSite, 1> SetJmp3CallSites;
  for (BasicBlock *BB : RPOT) {
    for (Instruction &I : *BB) {
      CallSite CS(&I);
      if (!CS)
        continue;
      if (CS.getCalledValue()->stripPointerCasts() !=
          SetJmp3->stripPointerCasts())
        continue;

      SetJmp3CallSites.push_back(CS);
    }
  }

  for (CallSite CS : SetJmp3CallSites) {
    auto &BBColors = BlockColors[CS->getParent()];
    BasicBlock *FuncletEntryBB = BBColors.front();
    bool InCleanup = isa<CleanupPadInst>(FuncletEntryBB->getFirstNonPHI());

    IRBuilder<> Builder(CS.getInstruction());
    Value *State;
    if (InCleanup) {
      Value *StateField =
          Builder.CreateStructGEP(nullptr, RegNode, StateFieldIndex);
      State = Builder.CreateLoad(StateField);
    } else {
      State = Builder.getInt32(getStateForCallSite(BlockColors, FuncInfo, CS));
    }
    rewriteSetJmpCallSite(Builder, F, CS, State);
  }
}

void WinEHStatePass::insertStateNumberStore(Instruction *IP, int State) {
  IRBuilder<> Builder(IP);
  Value *StateField =
      Builder.CreateStructGEP(nullptr, RegNode, StateFieldIndex);
  Builder.CreateStore(Builder.getInt32(State), StateField);
}