llvm.org GIT mirror llvm / 31ec888 lib / Transforms / Instrumentation / IndirectCallPromotion.cpp
31ec888

Tree @31ec888 (Download .tar.gz)

IndirectCallPromotion.cpp @31ec888raw · 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
//===-- IndirectCallPromotion.cpp - Optimizations based on value profiling ===//
//
//                      The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the transformation that promotes indirect calls to
// conditional direct calls when the indirect-call value profile metadata is
// available.
//
//===----------------------------------------------------------------------===//

#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/Analysis/IndirectCallPromotionAnalysis.h"
#include "llvm/Analysis/IndirectCallSiteVisitor.h"
#include "llvm/Analysis/OptimizationDiagnosticInfo.h"
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/PassManager.h"
#include "llvm/IR/Type.h"
#include "llvm/Pass.h"
#include "llvm/PassRegistry.h"
#include "llvm/PassSupport.h"
#include "llvm/ProfileData/InstrProf.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Transforms/PGOInstrumentation.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include <cassert>
#include <cstdint>
#include <vector>

using namespace llvm;

#define DEBUG_TYPE "pgo-icall-prom"

STATISTIC(NumOfPGOICallPromotion, "Number of indirect call promotions.");
STATISTIC(NumOfPGOICallsites, "Number of indirect call candidate sites.");

// Command line option to disable indirect-call promotion with the default as
// false. This is for debug purpose.
static cl::opt<bool> DisableICP("disable-icp", cl::init(false), cl::Hidden,
                                cl::desc("Disable indirect call promotion"));

// Set the cutoff value for the promotion. If the value is other than 0, we
// stop the transformation once the total number of promotions equals the cutoff
// value.
// For debug use only.
static cl::opt<unsigned>
    ICPCutOff("icp-cutoff", cl::init(0), cl::Hidden, cl::ZeroOrMore,
              cl::desc("Max number of promotions for this compilation"));

// If ICPCSSkip is non zero, the first ICPCSSkip callsites will be skipped.
// For debug use only.
static cl::opt<unsigned>
    ICPCSSkip("icp-csskip", cl::init(0), cl::Hidden, cl::ZeroOrMore,
              cl::desc("Skip Callsite up to this number for this compilation"));

// Set if the pass is called in LTO optimization. The difference for LTO mode
// is the pass won't prefix the source module name to the internal linkage
// symbols.
static cl::opt<bool> ICPLTOMode("icp-lto", cl::init(false), cl::Hidden,
                                cl::desc("Run indirect-call promotion in LTO "
                                         "mode"));

// Set if the pass is called in SamplePGO mode. The difference for SamplePGO
// mode is it will add prof metadatato the created direct call.
static cl::opt<bool>
    ICPSamplePGOMode("icp-samplepgo", cl::init(false), cl::Hidden,
                     cl::desc("Run indirect-call promotion in SamplePGO mode"));

// If the option is set to true, only call instructions will be considered for
// transformation -- invoke instructions will be ignored.
static cl::opt<bool>
    ICPCallOnly("icp-call-only", cl::init(false), cl::Hidden,
                cl::desc("Run indirect-call promotion for call instructions "
                         "only"));

// If the option is set to true, only invoke instructions will be considered for
// transformation -- call instructions will be ignored.
static cl::opt<bool> ICPInvokeOnly("icp-invoke-only", cl::init(false),
                                   cl::Hidden,
                                   cl::desc("Run indirect-call promotion for "
                                            "invoke instruction only"));

// Dump the function level IR if the transformation happened in this
// function. For debug use only.
static cl::opt<bool>
    ICPDUMPAFTER("icp-dumpafter", cl::init(false), cl::Hidden,
                 cl::desc("Dump IR after transformation happens"));

namespace {
class PGOIndirectCallPromotionLegacyPass : public ModulePass {
public:
  static char ID;

  PGOIndirectCallPromotionLegacyPass(bool InLTO = false, bool SamplePGO = false)
      : ModulePass(ID), InLTO(InLTO), SamplePGO(SamplePGO) {
    initializePGOIndirectCallPromotionLegacyPassPass(
        *PassRegistry::getPassRegistry());
  }

  void getAnalysisUsage(AnalysisUsage &AU) const override {
    AU.addRequired<ProfileSummaryInfoWrapperPass>();
  }

  StringRef getPassName() const override { return "PGOIndirectCallPromotion"; }

private:
  bool runOnModule(Module &M) override;

  // If this pass is called in LTO. We need to special handling the PGOFuncName
  // for the static variables due to LTO's internalization.
  bool InLTO;

  // If this pass is called in SamplePGO. We need to add the prof metadata to
  // the promoted direct call.
  bool SamplePGO;
};
} // end anonymous namespace

char PGOIndirectCallPromotionLegacyPass::ID = 0;
INITIALIZE_PASS_BEGIN(PGOIndirectCallPromotionLegacyPass, "pgo-icall-prom",
                      "Use PGO instrumentation profile to promote indirect "
                      "calls to direct calls.",
                      false, false)
INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)
INITIALIZE_PASS_END(PGOIndirectCallPromotionLegacyPass, "pgo-icall-prom",
                    "Use PGO instrumentation profile to promote indirect "
                    "calls to direct calls.",
                    false, false)

ModulePass *llvm::createPGOIndirectCallPromotionLegacyPass(bool InLTO,
                                                           bool SamplePGO) {
  return new PGOIndirectCallPromotionLegacyPass(InLTO, SamplePGO);
}

namespace {
// The class for main data structure to promote indirect calls to conditional
// direct calls.
class ICallPromotionFunc {
private:
  Function &F;
  Module *M;

  // Symtab that maps indirect call profile values to function names and
  // defines.
  InstrProfSymtab *Symtab;

  bool SamplePGO;

  OptimizationRemarkEmitter &ORE;

  // A struct that records the direct target and it's call count.
  struct PromotionCandidate {
    Function *TargetFunction;
    uint64_t Count;
    PromotionCandidate(Function *F, uint64_t C) : TargetFunction(F), Count(C) {}
  };

  // Check if the indirect-call call site should be promoted. Return the number
  // of promotions. Inst is the candidate indirect call, ValueDataRef
  // contains the array of value profile data for profiled targets,
  // TotalCount is the total profiled count of call executions, and
  // NumCandidates is the number of candidate entries in ValueDataRef.
  std::vector<PromotionCandidate> getPromotionCandidatesForCallSite(
      Instruction *Inst, const ArrayRef<InstrProfValueData> &ValueDataRef,
      uint64_t TotalCount, uint32_t NumCandidates);

  // Promote a list of targets for one indirect-call callsite. Return
  // the number of promotions.
  uint32_t tryToPromote(Instruction *Inst,
                        const std::vector<PromotionCandidate> &Candidates,
                        uint64_t &TotalCount);

  // Noncopyable
  ICallPromotionFunc(const ICallPromotionFunc &other) = delete;
  ICallPromotionFunc &operator=(const ICallPromotionFunc &other) = delete;

public:
  ICallPromotionFunc(Function &Func, Module *Modu, InstrProfSymtab *Symtab,
                     bool SamplePGO, OptimizationRemarkEmitter &ORE)
      : F(Func), M(Modu), Symtab(Symtab), SamplePGO(SamplePGO), ORE(ORE) {}

  bool processFunction(ProfileSummaryInfo *PSI);
};
} // end anonymous namespace

bool llvm::isLegalToPromote(Instruction *Inst, Function *F,
                            const char **Reason) {
  // Check the return type.
  Type *CallRetType = Inst->getType();
  if (!CallRetType->isVoidTy()) {
    Type *FuncRetType = F->getReturnType();
    if (FuncRetType != CallRetType &&
        !CastInst::isBitCastable(FuncRetType, CallRetType)) {
      if (Reason)
        *Reason = "Return type mismatch";
      return false;
    }
  }

  // Check if the arguments are compatible with the parameters
  FunctionType *DirectCalleeType = F->getFunctionType();
  unsigned ParamNum = DirectCalleeType->getFunctionNumParams();
  CallSite CS(Inst);
  unsigned ArgNum = CS.arg_size();

  if (ParamNum != ArgNum && !DirectCalleeType->isVarArg()) {
    if (Reason)
      *Reason = "The number of arguments mismatch";
    return false;
  }

  for (unsigned I = 0; I < ParamNum; ++I) {
    Type *PTy = DirectCalleeType->getFunctionParamType(I);
    Type *ATy = CS.getArgument(I)->getType();
    if (PTy == ATy)
      continue;
    if (!CastInst::castIsValid(Instruction::BitCast, CS.getArgument(I), PTy)) {
      if (Reason)
        *Reason = "Argument type mismatch";
      return false;
    }
  }

  DEBUG(dbgs() << " #" << NumOfPGOICallPromotion << " Promote the icall to "
               << F->getName() << "\n");
  return true;
}

// Indirect-call promotion heuristic. The direct targets are sorted based on
// the count. Stop at the first target that is not promoted.
std::vector<ICallPromotionFunc::PromotionCandidate>
ICallPromotionFunc::getPromotionCandidatesForCallSite(
    Instruction *Inst, const ArrayRef<InstrProfValueData> &ValueDataRef,
    uint64_t TotalCount, uint32_t NumCandidates) {
  std::vector<PromotionCandidate> Ret;

  DEBUG(dbgs() << " \nWork on callsite #" << NumOfPGOICallsites << *Inst
               << " Num_targets: " << ValueDataRef.size()
               << " Num_candidates: " << NumCandidates << "\n");
  NumOfPGOICallsites++;
  if (ICPCSSkip != 0 && NumOfPGOICallsites <= ICPCSSkip) {
    DEBUG(dbgs() << " Skip: User options.\n");
    return Ret;
  }

  for (uint32_t I = 0; I < NumCandidates; I++) {
    uint64_t Count = ValueDataRef[I].Count;
    assert(Count <= TotalCount);
    uint64_t Target = ValueDataRef[I].Value;
    DEBUG(dbgs() << " Candidate " << I << " Count=" << Count
                 << "  Target_func: " << Target << "\n");

    if (ICPInvokeOnly && dyn_cast<CallInst>(Inst)) {
      DEBUG(dbgs() << " Not promote: User options.\n");
      ORE.emit(OptimizationRemarkMissed(DEBUG_TYPE, "UserOptions", Inst)
               << " Not promote: User options");
      break;
    }
    if (ICPCallOnly && dyn_cast<InvokeInst>(Inst)) {
      DEBUG(dbgs() << " Not promote: User option.\n");
      ORE.emit(OptimizationRemarkMissed(DEBUG_TYPE, "UserOptions", Inst)
               << " Not promote: User options");
      break;
    }
    if (ICPCutOff != 0 && NumOfPGOICallPromotion >= ICPCutOff) {
      DEBUG(dbgs() << " Not promote: Cutoff reached.\n");
      ORE.emit(OptimizationRemarkMissed(DEBUG_TYPE, "CutOffReached", Inst)
               << " Not promote: Cutoff reached");
      break;
    }

    Function *TargetFunction = Symtab->getFunction(Target);
    if (TargetFunction == nullptr) {
      DEBUG(dbgs() << " Not promote: Cannot find the target\n");
      ORE.emit(OptimizationRemarkMissed(DEBUG_TYPE, "UnableToFindTarget", Inst)
               << "Cannot promote indirect call: target not found");
      break;
    }

    const char *Reason = nullptr;
    if (!isLegalToPromote(Inst, TargetFunction, &Reason)) {
      using namespace ore;
      ORE.emit(OptimizationRemarkMissed(DEBUG_TYPE, "UnableToPromote", Inst)
               << "Cannot promote indirect call to "
               << NV("TargetFunction", TargetFunction) << " with count of "
               << NV("Count", Count) << ": " << Reason);
      break;
    }

    Ret.push_back(PromotionCandidate(TargetFunction, Count));
    TotalCount -= Count;
  }
  return Ret;
}

// Create a diamond structure for If_Then_Else. Also update the profile
// count. Do the fix-up for the invoke instruction.
static void createIfThenElse(Instruction *Inst, Function *DirectCallee,
                             uint64_t Count, uint64_t TotalCount,
                             BasicBlock **DirectCallBB,
                             BasicBlock **IndirectCallBB,
                             BasicBlock **MergeBB) {
  CallSite CS(Inst);
  Value *OrigCallee = CS.getCalledValue();

  IRBuilder<> BBBuilder(Inst);
  LLVMContext &Ctx = Inst->getContext();
  Value *BCI1 =
      BBBuilder.CreateBitCast(OrigCallee, Type::getInt8PtrTy(Ctx), "");
  Value *BCI2 =
      BBBuilder.CreateBitCast(DirectCallee, Type::getInt8PtrTy(Ctx), "");
  Value *PtrCmp = BBBuilder.CreateICmpEQ(BCI1, BCI2, "");

  uint64_t ElseCount = TotalCount - Count;
  uint64_t MaxCount = (Count >= ElseCount ? Count : ElseCount);
  uint64_t Scale = calculateCountScale(MaxCount);
  MDBuilder MDB(Inst->getContext());
  MDNode *BranchWeights = MDB.createBranchWeights(
      scaleBranchCount(Count, Scale), scaleBranchCount(ElseCount, Scale));
  TerminatorInst *ThenTerm, *ElseTerm;
  SplitBlockAndInsertIfThenElse(PtrCmp, Inst, &ThenTerm, &ElseTerm,
                                BranchWeights);
  *DirectCallBB = ThenTerm->getParent();
  (*DirectCallBB)->setName("if.true.direct_targ");
  *IndirectCallBB = ElseTerm->getParent();
  (*IndirectCallBB)->setName("if.false.orig_indirect");
  *MergeBB = Inst->getParent();
  (*MergeBB)->setName("if.end.icp");

  // Special handing of Invoke instructions.
  InvokeInst *II = dyn_cast<InvokeInst>(Inst);
  if (!II)
    return;

  // We don't need branch instructions for invoke.
  ThenTerm->eraseFromParent();
  ElseTerm->eraseFromParent();

  // Add jump from Merge BB to the NormalDest. This is needed for the newly
  // created direct invoke stmt -- as its NormalDst will be fixed up to MergeBB.
  BranchInst::Create(II->getNormalDest(), *MergeBB);
}

// Find the PHI in BB that have the CallResult as the operand.
static bool getCallRetPHINode(BasicBlock *BB, Instruction *Inst) {
  BasicBlock *From = Inst->getParent();
  for (auto &I : *BB) {
    PHINode *PHI = dyn_cast<PHINode>(&I);
    if (!PHI)
      continue;
    int IX = PHI->getBasicBlockIndex(From);
    if (IX == -1)
      continue;
    Value *V = PHI->getIncomingValue(IX);
    if (dyn_cast<Instruction>(V) == Inst)
      return true;
  }
  return false;
}

// This method fixes up PHI nodes in BB where BB is the UnwindDest of an
// invoke instruction. In BB, there may be PHIs with incoming block being
// OrigBB (the MergeBB after if-then-else splitting). After moving the invoke
// instructions to its own BB, OrigBB is no longer the predecessor block of BB.
// Instead two new predecessors are added: IndirectCallBB and DirectCallBB,
// so the PHI node's incoming BBs need to be fixed up accordingly.
static void fixupPHINodeForUnwind(Instruction *Inst, BasicBlock *BB,
                                  BasicBlock *OrigBB,
                                  BasicBlock *IndirectCallBB,
                                  BasicBlock *DirectCallBB) {
  for (auto &I : *BB) {
    PHINode *PHI = dyn_cast<PHINode>(&I);
    if (!PHI)
      continue;
    int IX = PHI->getBasicBlockIndex(OrigBB);
    if (IX == -1)
      continue;
    Value *V = PHI->getIncomingValue(IX);
    PHI->addIncoming(V, IndirectCallBB);
    PHI->setIncomingBlock(IX, DirectCallBB);
  }
}

// This method fixes up PHI nodes in BB where BB is the NormalDest of an
// invoke instruction. In BB, there may be PHIs with incoming block being
// OrigBB (the MergeBB after if-then-else splitting). After moving the invoke
// instructions to its own BB, a new incoming edge will be added to the original
// NormalDstBB from the IndirectCallBB.
static void fixupPHINodeForNormalDest(Instruction *Inst, BasicBlock *BB,
                                      BasicBlock *OrigBB,
                                      BasicBlock *IndirectCallBB,
                                      Instruction *NewInst) {
  for (auto &I : *BB) {
    PHINode *PHI = dyn_cast<PHINode>(&I);
    if (!PHI)
      continue;
    int IX = PHI->getBasicBlockIndex(OrigBB);
    if (IX == -1)
      continue;
    Value *V = PHI->getIncomingValue(IX);
    if (dyn_cast<Instruction>(V) == Inst) {
      PHI->setIncomingBlock(IX, IndirectCallBB);
      PHI->addIncoming(NewInst, OrigBB);
      continue;
    }
    PHI->addIncoming(V, IndirectCallBB);
  }
}

// Add a bitcast instruction to the direct-call return value if needed.
static Instruction *insertCallRetCast(const Instruction *Inst,
                                      Instruction *DirectCallInst,
                                      Function *DirectCallee) {
  if (Inst->getType()->isVoidTy())
    return DirectCallInst;

  Type *CallRetType = Inst->getType();
  Type *FuncRetType = DirectCallee->getReturnType();
  if (FuncRetType == CallRetType)
    return DirectCallInst;

  BasicBlock *InsertionBB;
  if (CallInst *CI = dyn_cast<CallInst>(DirectCallInst))
    InsertionBB = CI->getParent();
  else
    InsertionBB = (dyn_cast<InvokeInst>(DirectCallInst))->getNormalDest();

  return (new BitCastInst(DirectCallInst, CallRetType, "",
                          InsertionBB->getTerminator()));
}

// Create a DirectCall instruction in the DirectCallBB.
// Parameter Inst is the indirect-call (invoke) instruction.
// DirectCallee is the decl of the direct-call (invoke) target.
// DirecallBB is the BB that the direct-call (invoke) instruction is inserted.
// MergeBB is the bottom BB of the if-then-else-diamond after the
// transformation. For invoke instruction, the edges from DirectCallBB and
// IndirectCallBB to MergeBB are removed before this call (during
// createIfThenElse).
static Instruction *createDirectCallInst(const Instruction *Inst,
                                         Function *DirectCallee,
                                         BasicBlock *DirectCallBB,
                                         BasicBlock *MergeBB) {
  Instruction *NewInst = Inst->clone();
  if (CallInst *CI = dyn_cast<CallInst>(NewInst)) {
    CI->setCalledFunction(DirectCallee);
    CI->mutateFunctionType(DirectCallee->getFunctionType());
  } else {
    // Must be an invoke instruction. Direct invoke's normal destination is
    // fixed up to MergeBB. MergeBB is the place where return cast is inserted.
    // Also since IndirectCallBB does not have an edge to MergeBB, there is no
    // need to insert new PHIs into MergeBB.
    InvokeInst *II = dyn_cast<InvokeInst>(NewInst);
    assert(II);
    II->setCalledFunction(DirectCallee);
    II->mutateFunctionType(DirectCallee->getFunctionType());
    II->setNormalDest(MergeBB);
  }

  DirectCallBB->getInstList().insert(DirectCallBB->getFirstInsertionPt(),
                                     NewInst);

  // Clear the value profile data.
  NewInst->setMetadata(LLVMContext::MD_prof, nullptr);
  CallSite NewCS(NewInst);
  FunctionType *DirectCalleeType = DirectCallee->getFunctionType();
  unsigned ParamNum = DirectCalleeType->getFunctionNumParams();
  for (unsigned I = 0; I < ParamNum; ++I) {
    Type *ATy = NewCS.getArgument(I)->getType();
    Type *PTy = DirectCalleeType->getParamType(I);
    if (ATy != PTy) {
      BitCastInst *BI = new BitCastInst(NewCS.getArgument(I), PTy, "", NewInst);
      NewCS.setArgument(I, BI);
    }
  }

  return insertCallRetCast(Inst, NewInst, DirectCallee);
}

// Create a PHI to unify the return values of calls.
static void insertCallRetPHI(Instruction *Inst, Instruction *CallResult,
                             Function *DirectCallee) {
  if (Inst->getType()->isVoidTy())
    return;

  if (Inst->use_empty())
    return;

  BasicBlock *RetValBB = CallResult->getParent();

  BasicBlock *PHIBB;
  if (InvokeInst *II = dyn_cast<InvokeInst>(CallResult))
    RetValBB = II->getNormalDest();

  PHIBB = RetValBB->getSingleSuccessor();
  if (getCallRetPHINode(PHIBB, Inst))
    return;

  PHINode *CallRetPHI = PHINode::Create(Inst->getType(), 0);
  PHIBB->getInstList().push_front(CallRetPHI);
  Inst->replaceAllUsesWith(CallRetPHI);
  CallRetPHI->addIncoming(Inst, Inst->getParent());
  CallRetPHI->addIncoming(CallResult, RetValBB);
}

// This function does the actual indirect-call promotion transformation:
// For an indirect-call like:
//     Ret = (*Foo)(Args);
// It transforms to:
//     if (Foo == DirectCallee)
//        Ret1 = DirectCallee(Args);
//     else
//        Ret2 = (*Foo)(Args);
//     Ret = phi(Ret1, Ret2);
// It adds type casts for the args do not match the parameters and the return
// value. Branch weights metadata also updated.
// If \p AttachProfToDirectCall is true, a prof metadata is attached to the
// new direct call to contain \p Count. This is used by SamplePGO inliner to
// check callsite hotness.
// Returns the promoted direct call instruction.
Instruction *llvm::promoteIndirectCall(Instruction *Inst,
                                       Function *DirectCallee, uint64_t Count,
                                       uint64_t TotalCount,
                                       bool AttachProfToDirectCall,
                                       OptimizationRemarkEmitter *ORE) {
  assert(DirectCallee != nullptr);
  BasicBlock *BB = Inst->getParent();
  // Just to suppress the non-debug build warning.
  (void)BB;
  DEBUG(dbgs() << "\n\n== Basic Block Before ==\n");
  DEBUG(dbgs() << *BB << "\n");

  BasicBlock *DirectCallBB, *IndirectCallBB, *MergeBB;
  createIfThenElse(Inst, DirectCallee, Count, TotalCount, &DirectCallBB,
                   &IndirectCallBB, &MergeBB);

  Instruction *NewInst =
      createDirectCallInst(Inst, DirectCallee, DirectCallBB, MergeBB);

  if (AttachProfToDirectCall) {
    SmallVector<uint32_t, 1> Weights;
    Weights.push_back(Count);
    MDBuilder MDB(NewInst->getContext());
    if (Instruction *DI = dyn_cast<Instruction>(NewInst->stripPointerCasts()))
      DI->setMetadata(LLVMContext::MD_prof, MDB.createBranchWeights(Weights));
  }

  // Move Inst from MergeBB to IndirectCallBB.
  Inst->removeFromParent();
  IndirectCallBB->getInstList().insert(IndirectCallBB->getFirstInsertionPt(),
                                       Inst);

  if (InvokeInst *II = dyn_cast<InvokeInst>(Inst)) {
    // At this point, the original indirect invoke instruction has the original
    // UnwindDest and NormalDest. For the direct invoke instruction, the
    // NormalDest points to MergeBB, and MergeBB jumps to the original
    // NormalDest. MergeBB might have a new bitcast instruction for the return
    // value. The PHIs are with the original NormalDest. Since we now have two
    // incoming edges to NormalDest and UnwindDest, we have to do some fixups.
    //
    // UnwindDest will not use the return value. So pass nullptr here.
    fixupPHINodeForUnwind(Inst, II->getUnwindDest(), MergeBB, IndirectCallBB,
                          DirectCallBB);
    // We don't need to update the operand from NormalDest for DirectCallBB.
    // Pass nullptr here.
    fixupPHINodeForNormalDest(Inst, II->getNormalDest(), MergeBB,
                              IndirectCallBB, NewInst);
  }

  insertCallRetPHI(Inst, NewInst, DirectCallee);

  DEBUG(dbgs() << "\n== Basic Blocks After ==\n");
  DEBUG(dbgs() << *BB << *DirectCallBB << *IndirectCallBB << *MergeBB << "\n");

  using namespace ore;
  if (ORE)
    ORE->emit(OptimizationRemark(DEBUG_TYPE, "Promoted", Inst)
              << "Promote indirect call to " << NV("DirectCallee", DirectCallee)
              << " with count " << NV("Count", Count) << " out of "
              << NV("TotalCount", TotalCount));
  return NewInst;
}

// Promote indirect-call to conditional direct-call for one callsite.
uint32_t ICallPromotionFunc::tryToPromote(
    Instruction *Inst, const std::vector<PromotionCandidate> &Candidates,
    uint64_t &TotalCount) {
  uint32_t NumPromoted = 0;

  for (auto &C : Candidates) {
    uint64_t Count = C.Count;
    promoteIndirectCall(Inst, C.TargetFunction, Count, TotalCount, SamplePGO,
                        &ORE);
    assert(TotalCount >= Count);
    TotalCount -= Count;
    NumOfPGOICallPromotion++;
    NumPromoted++;
  }
  return NumPromoted;
}

// Traverse all the indirect-call callsite and get the value profile
// annotation to perform indirect-call promotion.
bool ICallPromotionFunc::processFunction(ProfileSummaryInfo *PSI) {
  bool Changed = false;
  ICallPromotionAnalysis ICallAnalysis;
  for (auto &I : findIndirectCallSites(F)) {
    uint32_t NumVals, NumCandidates;
    uint64_t TotalCount;
    auto ICallProfDataRef = ICallAnalysis.getPromotionCandidatesForInstruction(
        I, NumVals, TotalCount, NumCandidates);
    if (!NumCandidates ||
        (PSI && PSI->hasProfileSummary() && !PSI->isHotCount(TotalCount)))
      continue;
    auto PromotionCandidates = getPromotionCandidatesForCallSite(
        I, ICallProfDataRef, TotalCount, NumCandidates);
    uint32_t NumPromoted = tryToPromote(I, PromotionCandidates, TotalCount);
    if (NumPromoted == 0)
      continue;

    Changed = true;
    // Adjust the MD.prof metadata. First delete the old one.
    I->setMetadata(LLVMContext::MD_prof, nullptr);
    // If all promoted, we don't need the MD.prof metadata.
    if (TotalCount == 0 || NumPromoted == NumVals)
      continue;
    // Otherwise we need update with the un-promoted records back.
    annotateValueSite(*M, *I, ICallProfDataRef.slice(NumPromoted), TotalCount,
                      IPVK_IndirectCallTarget, NumCandidates);
  }
  return Changed;
}

// A wrapper function that does the actual work.
static bool promoteIndirectCalls(Module &M, ProfileSummaryInfo *PSI,
                                 bool InLTO, bool SamplePGO,
                                 ModuleAnalysisManager *AM = nullptr) {
  if (DisableICP)
    return false;
  InstrProfSymtab Symtab;
  if (Error E = Symtab.create(M, InLTO)) {
    std::string SymtabFailure = toString(std::move(E));
    DEBUG(dbgs() << "Failed to create symtab: " << SymtabFailure << "\n");
    (void)SymtabFailure;
    return false;
  }
  bool Changed = false;
  for (auto &F : M) {
    if (F.isDeclaration())
      continue;
    if (F.hasFnAttribute(Attribute::OptimizeNone))
      continue;

    std::unique_ptr<OptimizationRemarkEmitter> OwnedORE;
    OptimizationRemarkEmitter *ORE;
    if (AM) {
      auto &FAM =
          AM->getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
      ORE = &FAM.getResult<OptimizationRemarkEmitterAnalysis>(F);
    } else {
      OwnedORE = make_unique<OptimizationRemarkEmitter>(&F);
      ORE = OwnedORE.get();
    }

    ICallPromotionFunc ICallPromotion(F, &M, &Symtab, SamplePGO, *ORE);
    bool FuncChanged = ICallPromotion.processFunction(PSI);
    if (ICPDUMPAFTER && FuncChanged) {
      DEBUG(dbgs() << "\n== IR Dump After =="; F.print(dbgs()));
      DEBUG(dbgs() << "\n");
    }
    Changed |= FuncChanged;
    if (ICPCutOff != 0 && NumOfPGOICallPromotion >= ICPCutOff) {
      DEBUG(dbgs() << " Stop: Cutoff reached.\n");
      break;
    }
  }
  return Changed;
}

bool PGOIndirectCallPromotionLegacyPass::runOnModule(Module &M) {
  ProfileSummaryInfo *PSI =
      getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();

  // Command-line option has the priority for InLTO.
  return promoteIndirectCalls(M, PSI, InLTO | ICPLTOMode,
                              SamplePGO | ICPSamplePGOMode);
}

PreservedAnalyses PGOIndirectCallPromotion::run(Module &M,
                                                ModuleAnalysisManager &AM) {
  ProfileSummaryInfo *PSI = &AM.getResult<ProfileSummaryAnalysis>(M);

  if (!promoteIndirectCalls(M, PSI, InLTO | ICPLTOMode,
                            SamplePGO | ICPSamplePGOMode, &AM))
    return PreservedAnalyses::all();

  return PreservedAnalyses::none();
}