1//===- AliasSetTracker.cpp - Alias Sets Tracker implementation-------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the AliasSetTracker and AliasSet classes.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Analysis/AliasSetTracker.h"
15#include "llvm/Analysis/AliasAnalysis.h"
16#include "llvm/IR/DataLayout.h"
17#include "llvm/IR/InstIterator.h"
18#include "llvm/IR/Instructions.h"
19#include "llvm/IR/IntrinsicInst.h"
20#include "llvm/IR/Module.h"
21#include "llvm/IR/LLVMContext.h"
22#include "llvm/IR/Type.h"
23#include "llvm/Pass.h"
24#include "llvm/Support/Debug.h"
25#include "llvm/Support/ErrorHandling.h"
26#include "llvm/Support/raw_ostream.h"
27using namespace llvm;
28
29/// mergeSetIn - Merge the specified alias set into this alias set.
30///
31void AliasSet::mergeSetIn(AliasSet &AS, AliasSetTracker &AST) {
32  assert(!AS.Forward && "Alias set is already forwarding!");
33  assert(!Forward && "This set is a forwarding set!!");
34
35  // Update the alias and access types of this set...
36  Access |= AS.Access;
37  Alias  |= AS.Alias;
38  Volatile |= AS.Volatile;
39
40  if (Alias == SetMustAlias) {
41    // Check that these two merged sets really are must aliases.  Since both
42    // used to be must-alias sets, we can just check any pointer from each set
43    // for aliasing.
44    AliasAnalysis &AA = AST.getAliasAnalysis();
45    PointerRec *L = getSomePointer();
46    PointerRec *R = AS.getSomePointer();
47
48    // If the pointers are not a must-alias pair, this set becomes a may alias.
49    if (AA.alias(MemoryLocation(L->getValue(), L->getSize(), L->getAAInfo()),
50                 MemoryLocation(R->getValue(), R->getSize(), R->getAAInfo())) !=
51        MustAlias)
52      Alias = SetMayAlias;
53  }
54
55  bool ASHadUnknownInsts = !AS.UnknownInsts.empty();
56  if (UnknownInsts.empty()) {            // Merge call sites...
57    if (ASHadUnknownInsts) {
58      std::swap(UnknownInsts, AS.UnknownInsts);
59      addRef();
60    }
61  } else if (ASHadUnknownInsts) {
62    UnknownInsts.insert(UnknownInsts.end(), AS.UnknownInsts.begin(), AS.UnknownInsts.end());
63    AS.UnknownInsts.clear();
64  }
65
66  AS.Forward = this;  // Forward across AS now...
67  addRef();           // AS is now pointing to us...
68
69  // Merge the list of constituent pointers...
70  if (AS.PtrList) {
71    *PtrListEnd = AS.PtrList;
72    AS.PtrList->setPrevInList(PtrListEnd);
73    PtrListEnd = AS.PtrListEnd;
74
75    AS.PtrList = nullptr;
76    AS.PtrListEnd = &AS.PtrList;
77    assert(*AS.PtrListEnd == nullptr && "End of list is not null?");
78  }
79  if (ASHadUnknownInsts)
80    AS.dropRef(AST);
81}
82
83void AliasSetTracker::removeAliasSet(AliasSet *AS) {
84  if (AliasSet *Fwd = AS->Forward) {
85    Fwd->dropRef(*this);
86    AS->Forward = nullptr;
87  }
88  AliasSets.erase(AS);
89}
90
91void AliasSet::removeFromTracker(AliasSetTracker &AST) {
92  assert(RefCount == 0 && "Cannot remove non-dead alias set from tracker!");
93  AST.removeAliasSet(this);
94}
95
96void AliasSet::addPointer(AliasSetTracker &AST, PointerRec &Entry,
97                          uint64_t Size, const AAMDNodes &AAInfo,
98                          bool KnownMustAlias) {
99  assert(!Entry.hasAliasSet() && "Entry already in set!");
100
101  // Check to see if we have to downgrade to _may_ alias.
102  if (isMustAlias() && !KnownMustAlias)
103    if (PointerRec *P = getSomePointer()) {
104      AliasAnalysis &AA = AST.getAliasAnalysis();
105      AliasResult Result =
106          AA.alias(MemoryLocation(P->getValue(), P->getSize(), P->getAAInfo()),
107                   MemoryLocation(Entry.getValue(), Size, AAInfo));
108      if (Result != MustAlias)
109        Alias = SetMayAlias;
110      else                  // First entry of must alias must have maximum size!
111        P->updateSizeAndAAInfo(Size, AAInfo);
112      assert(Result != NoAlias && "Cannot be part of must set!");
113    }
114
115  Entry.setAliasSet(this);
116  Entry.updateSizeAndAAInfo(Size, AAInfo);
117
118  // Add it to the end of the list...
119  assert(*PtrListEnd == nullptr && "End of list is not null?");
120  *PtrListEnd = &Entry;
121  PtrListEnd = Entry.setPrevInList(PtrListEnd);
122  assert(*PtrListEnd == nullptr && "End of list is not null?");
123  addRef();               // Entry points to alias set.
124}
125
126void AliasSet::addUnknownInst(Instruction *I, AliasAnalysis &AA) {
127  if (UnknownInsts.empty())
128    addRef();
129  UnknownInsts.emplace_back(I);
130
131  if (!I->mayWriteToMemory()) {
132    Alias = SetMayAlias;
133    Access |= RefAccess;
134    return;
135  }
136
137  // FIXME: This should use mod/ref information to make this not suck so bad
138  Alias = SetMayAlias;
139  Access = ModRefAccess;
140}
141
142/// aliasesPointer - Return true if the specified pointer "may" (or must)
143/// alias one of the members in the set.
144///
145bool AliasSet::aliasesPointer(const Value *Ptr, uint64_t Size,
146                              const AAMDNodes &AAInfo,
147                              AliasAnalysis &AA) const {
148  if (Alias == SetMustAlias) {
149    assert(UnknownInsts.empty() && "Illegal must alias set!");
150
151    // If this is a set of MustAliases, only check to see if the pointer aliases
152    // SOME value in the set.
153    PointerRec *SomePtr = getSomePointer();
154    assert(SomePtr && "Empty must-alias set??");
155    return AA.alias(MemoryLocation(SomePtr->getValue(), SomePtr->getSize(),
156                                   SomePtr->getAAInfo()),
157                    MemoryLocation(Ptr, Size, AAInfo));
158  }
159
160  // If this is a may-alias set, we have to check all of the pointers in the set
161  // to be sure it doesn't alias the set...
162  for (iterator I = begin(), E = end(); I != E; ++I)
163    if (AA.alias(MemoryLocation(Ptr, Size, AAInfo),
164                 MemoryLocation(I.getPointer(), I.getSize(), I.getAAInfo())))
165      return true;
166
167  // Check the unknown instructions...
168  if (!UnknownInsts.empty()) {
169    for (unsigned i = 0, e = UnknownInsts.size(); i != e; ++i)
170      if (AA.getModRefInfo(UnknownInsts[i],
171                           MemoryLocation(Ptr, Size, AAInfo)) != MRI_NoModRef)
172        return true;
173  }
174
175  return false;
176}
177
178bool AliasSet::aliasesUnknownInst(const Instruction *Inst,
179                                  AliasAnalysis &AA) const {
180  if (!Inst->mayReadOrWriteMemory())
181    return false;
182
183  for (unsigned i = 0, e = UnknownInsts.size(); i != e; ++i) {
184    ImmutableCallSite C1(getUnknownInst(i)), C2(Inst);
185    if (!C1 || !C2 || AA.getModRefInfo(C1, C2) != MRI_NoModRef ||
186        AA.getModRefInfo(C2, C1) != MRI_NoModRef)
187      return true;
188  }
189
190  for (iterator I = begin(), E = end(); I != E; ++I)
191    if (AA.getModRefInfo(Inst, MemoryLocation(I.getPointer(), I.getSize(),
192                                              I.getAAInfo())) != MRI_NoModRef)
193      return true;
194
195  return false;
196}
197
198void AliasSetTracker::clear() {
199  // Delete all the PointerRec entries.
200  for (PointerMapType::iterator I = PointerMap.begin(), E = PointerMap.end();
201       I != E; ++I)
202    I->second->eraseFromList();
203
204  PointerMap.clear();
205
206  // The alias sets should all be clear now.
207  AliasSets.clear();
208}
209
210
211/// mergeAliasSetsForPointer - Given a pointer, merge all alias sets that may
212/// alias the pointer. Return the unified set, or nullptr if no set that aliases
213/// the pointer was found.
214AliasSet *AliasSetTracker::mergeAliasSetsForPointer(const Value *Ptr,
215                                                    uint64_t Size,
216                                                    const AAMDNodes &AAInfo) {
217  AliasSet *FoundSet = nullptr;
218  for (iterator I = begin(), E = end(); I != E;) {
219    iterator Cur = I++;
220    if (Cur->Forward || !Cur->aliasesPointer(Ptr, Size, AAInfo, AA)) continue;
221
222    if (!FoundSet) {      // If this is the first alias set ptr can go into.
223      FoundSet = &*Cur;   // Remember it.
224    } else {              // Otherwise, we must merge the sets.
225      FoundSet->mergeSetIn(*Cur, *this);     // Merge in contents.
226    }
227  }
228
229  return FoundSet;
230}
231
232/// containsPointer - Return true if the specified location is represented by
233/// this alias set, false otherwise.  This does not modify the AST object or
234/// alias sets.
235bool AliasSetTracker::containsPointer(const Value *Ptr, uint64_t Size,
236                                      const AAMDNodes &AAInfo) const {
237  for (const AliasSet &AS : *this)
238    if (!AS.Forward && AS.aliasesPointer(Ptr, Size, AAInfo, AA))
239      return true;
240  return false;
241}
242
243bool AliasSetTracker::containsUnknown(const Instruction *Inst) const {
244  for (const AliasSet &AS : *this)
245    if (!AS.Forward && AS.aliasesUnknownInst(Inst, AA))
246      return true;
247  return false;
248}
249
250AliasSet *AliasSetTracker::findAliasSetForUnknownInst(Instruction *Inst) {
251  AliasSet *FoundSet = nullptr;
252  for (iterator I = begin(), E = end(); I != E;) {
253    iterator Cur = I++;
254    if (Cur->Forward || !Cur->aliasesUnknownInst(Inst, AA))
255      continue;
256    if (!FoundSet)            // If this is the first alias set ptr can go into.
257      FoundSet = &*Cur;       // Remember it.
258    else if (!Cur->Forward)   // Otherwise, we must merge the sets.
259      FoundSet->mergeSetIn(*Cur, *this);     // Merge in contents.
260  }
261  return FoundSet;
262}
263
264
265
266
267/// getAliasSetForPointer - Return the alias set that the specified pointer
268/// lives in.
269AliasSet &AliasSetTracker::getAliasSetForPointer(Value *Pointer, uint64_t Size,
270                                                 const AAMDNodes &AAInfo,
271                                                 bool *New) {
272  AliasSet::PointerRec &Entry = getEntryFor(Pointer);
273
274  // Check to see if the pointer is already known.
275  if (Entry.hasAliasSet()) {
276    // If the size changed, we may need to merge several alias sets.
277    // Note that we can *not* return the result of mergeAliasSetsForPointer
278    // due to a quirk of alias analysis behavior. Since alias(undef, undef)
279    // is NoAlias, mergeAliasSetsForPointer(undef, ...) will not find the
280    // the right set for undef, even if it exists.
281    if (Entry.updateSizeAndAAInfo(Size, AAInfo))
282      mergeAliasSetsForPointer(Pointer, Size, AAInfo);
283    // Return the set!
284    return *Entry.getAliasSet(*this)->getForwardedTarget(*this);
285  }
286
287  if (AliasSet *AS = mergeAliasSetsForPointer(Pointer, Size, AAInfo)) {
288    // Add it to the alias set it aliases.
289    AS->addPointer(*this, Entry, Size, AAInfo);
290    return *AS;
291  }
292
293  if (New) *New = true;
294  // Otherwise create a new alias set to hold the loaded pointer.
295  AliasSets.push_back(new AliasSet());
296  AliasSets.back().addPointer(*this, Entry, Size, AAInfo);
297  return AliasSets.back();
298}
299
300bool AliasSetTracker::add(Value *Ptr, uint64_t Size, const AAMDNodes &AAInfo) {
301  bool NewPtr;
302  addPointer(Ptr, Size, AAInfo, AliasSet::NoAccess, NewPtr);
303  return NewPtr;
304}
305
306
307bool AliasSetTracker::add(LoadInst *LI) {
308  if (isStrongerThanMonotonic(LI->getOrdering())) return addUnknown(LI);
309
310  AAMDNodes AAInfo;
311  LI->getAAMetadata(AAInfo);
312
313  AliasSet::AccessLattice Access = AliasSet::RefAccess;
314  bool NewPtr;
315  const DataLayout &DL = LI->getModule()->getDataLayout();
316  AliasSet &AS = addPointer(LI->getOperand(0),
317                            DL.getTypeStoreSize(LI->getType()),
318                            AAInfo, Access, NewPtr);
319  if (LI->isVolatile()) AS.setVolatile();
320  return NewPtr;
321}
322
323bool AliasSetTracker::add(StoreInst *SI) {
324  if (isStrongerThanMonotonic(SI->getOrdering())) return addUnknown(SI);
325
326  AAMDNodes AAInfo;
327  SI->getAAMetadata(AAInfo);
328
329  AliasSet::AccessLattice Access = AliasSet::ModAccess;
330  bool NewPtr;
331  const DataLayout &DL = SI->getModule()->getDataLayout();
332  Value *Val = SI->getOperand(0);
333  AliasSet &AS = addPointer(SI->getOperand(1),
334                            DL.getTypeStoreSize(Val->getType()),
335                            AAInfo, Access, NewPtr);
336  if (SI->isVolatile()) AS.setVolatile();
337  return NewPtr;
338}
339
340bool AliasSetTracker::add(VAArgInst *VAAI) {
341  AAMDNodes AAInfo;
342  VAAI->getAAMetadata(AAInfo);
343
344  bool NewPtr;
345  addPointer(VAAI->getOperand(0), MemoryLocation::UnknownSize, AAInfo,
346             AliasSet::ModRefAccess, NewPtr);
347  return NewPtr;
348}
349
350bool AliasSetTracker::add(MemSetInst *MSI) {
351  AAMDNodes AAInfo;
352  MSI->getAAMetadata(AAInfo);
353
354  bool NewPtr;
355  uint64_t Len;
356
357  if (ConstantInt *C = dyn_cast<ConstantInt>(MSI->getLength()))
358    Len = C->getZExtValue();
359  else
360    Len = MemoryLocation::UnknownSize;
361
362  AliasSet &AS =
363      addPointer(MSI->getRawDest(), Len, AAInfo, AliasSet::ModAccess, NewPtr);
364  if (MSI->isVolatile())
365    AS.setVolatile();
366  return NewPtr;
367}
368
369bool AliasSetTracker::addUnknown(Instruction *Inst) {
370  if (isa<DbgInfoIntrinsic>(Inst))
371    return true; // Ignore DbgInfo Intrinsics.
372  if (!Inst->mayReadOrWriteMemory())
373    return true; // doesn't alias anything
374
375  AliasSet *AS = findAliasSetForUnknownInst(Inst);
376  if (AS) {
377    AS->addUnknownInst(Inst, AA);
378    return false;
379  }
380  AliasSets.push_back(new AliasSet());
381  AS = &AliasSets.back();
382  AS->addUnknownInst(Inst, AA);
383  return true;
384}
385
386bool AliasSetTracker::add(Instruction *I) {
387  // Dispatch to one of the other add methods.
388  if (LoadInst *LI = dyn_cast<LoadInst>(I))
389    return add(LI);
390  if (StoreInst *SI = dyn_cast<StoreInst>(I))
391    return add(SI);
392  if (VAArgInst *VAAI = dyn_cast<VAArgInst>(I))
393    return add(VAAI);
394  if (MemSetInst *MSI = dyn_cast<MemSetInst>(I))
395    return add(MSI);
396  return addUnknown(I);
397  // FIXME: add support of memcpy and memmove.
398}
399
400void AliasSetTracker::add(BasicBlock &BB) {
401  for (auto &I : BB)
402    add(&I);
403}
404
405void AliasSetTracker::add(const AliasSetTracker &AST) {
406  assert(&AA == &AST.AA &&
407         "Merging AliasSetTracker objects with different Alias Analyses!");
408
409  // Loop over all of the alias sets in AST, adding the pointers contained
410  // therein into the current alias sets.  This can cause alias sets to be
411  // merged together in the current AST.
412  for (const AliasSet &AS : AST) {
413    if (AS.Forward)
414      continue; // Ignore forwarding alias sets
415
416    // If there are any call sites in the alias set, add them to this AST.
417    for (unsigned i = 0, e = AS.UnknownInsts.size(); i != e; ++i)
418      add(AS.UnknownInsts[i]);
419
420    // Loop over all of the pointers in this alias set.
421    bool X;
422    for (AliasSet::iterator ASI = AS.begin(), E = AS.end(); ASI != E; ++ASI) {
423      AliasSet &NewAS = addPointer(ASI.getPointer(), ASI.getSize(),
424                                   ASI.getAAInfo(),
425                                   (AliasSet::AccessLattice)AS.Access, X);
426      if (AS.isVolatile()) NewAS.setVolatile();
427    }
428  }
429}
430
431/// remove - Remove the specified (potentially non-empty) alias set from the
432/// tracker.
433void AliasSetTracker::remove(AliasSet &AS) {
434  // Drop all call sites.
435  if (!AS.UnknownInsts.empty())
436    AS.dropRef(*this);
437  AS.UnknownInsts.clear();
438
439  // Clear the alias set.
440  unsigned NumRefs = 0;
441  while (!AS.empty()) {
442    AliasSet::PointerRec *P = AS.PtrList;
443
444    Value *ValToRemove = P->getValue();
445
446    // Unlink and delete entry from the list of values.
447    P->eraseFromList();
448
449    // Remember how many references need to be dropped.
450    ++NumRefs;
451
452    // Finally, remove the entry.
453    PointerMap.erase(ValToRemove);
454  }
455
456  // Stop using the alias set, removing it.
457  AS.RefCount -= NumRefs;
458  if (AS.RefCount == 0)
459    AS.removeFromTracker(*this);
460}
461
462bool
463AliasSetTracker::remove(Value *Ptr, uint64_t Size, const AAMDNodes &AAInfo) {
464  AliasSet *AS = mergeAliasSetsForPointer(Ptr, Size, AAInfo);
465  if (!AS) return false;
466  remove(*AS);
467  return true;
468}
469
470bool AliasSetTracker::remove(LoadInst *LI) {
471  const DataLayout &DL = LI->getModule()->getDataLayout();
472  uint64_t Size = DL.getTypeStoreSize(LI->getType());
473
474  AAMDNodes AAInfo;
475  LI->getAAMetadata(AAInfo);
476
477  AliasSet *AS = mergeAliasSetsForPointer(LI->getOperand(0), Size, AAInfo);
478  if (!AS) return false;
479  remove(*AS);
480  return true;
481}
482
483bool AliasSetTracker::remove(StoreInst *SI) {
484  const DataLayout &DL = SI->getModule()->getDataLayout();
485  uint64_t Size = DL.getTypeStoreSize(SI->getOperand(0)->getType());
486
487  AAMDNodes AAInfo;
488  SI->getAAMetadata(AAInfo);
489
490  AliasSet *AS = mergeAliasSetsForPointer(SI->getOperand(1), Size, AAInfo);
491  if (!AS) return false;
492  remove(*AS);
493  return true;
494}
495
496bool AliasSetTracker::remove(VAArgInst *VAAI) {
497  AAMDNodes AAInfo;
498  VAAI->getAAMetadata(AAInfo);
499
500  AliasSet *AS = mergeAliasSetsForPointer(VAAI->getOperand(0),
501                                          MemoryLocation::UnknownSize, AAInfo);
502  if (!AS) return false;
503  remove(*AS);
504  return true;
505}
506
507bool AliasSetTracker::remove(MemSetInst *MSI) {
508  AAMDNodes AAInfo;
509  MSI->getAAMetadata(AAInfo);
510  uint64_t Len;
511
512  if (ConstantInt *C = dyn_cast<ConstantInt>(MSI->getLength()))
513    Len = C->getZExtValue();
514  else
515    Len = MemoryLocation::UnknownSize;
516
517  AliasSet *AS = mergeAliasSetsForPointer(MSI->getRawDest(), Len, AAInfo);
518  if (!AS)
519    return false;
520  remove(*AS);
521  return true;
522}
523
524bool AliasSetTracker::removeUnknown(Instruction *I) {
525  if (!I->mayReadOrWriteMemory())
526    return false; // doesn't alias anything
527
528  AliasSet *AS = findAliasSetForUnknownInst(I);
529  if (!AS) return false;
530  remove(*AS);
531  return true;
532}
533
534bool AliasSetTracker::remove(Instruction *I) {
535  // Dispatch to one of the other remove methods...
536  if (LoadInst *LI = dyn_cast<LoadInst>(I))
537    return remove(LI);
538  if (StoreInst *SI = dyn_cast<StoreInst>(I))
539    return remove(SI);
540  if (VAArgInst *VAAI = dyn_cast<VAArgInst>(I))
541    return remove(VAAI);
542  if (MemSetInst *MSI = dyn_cast<MemSetInst>(I))
543    return remove(MSI);
544  return removeUnknown(I);
545  // FIXME: add support of memcpy and memmove.
546}
547
548
549// deleteValue method - This method is used to remove a pointer value from the
550// AliasSetTracker entirely.  It should be used when an instruction is deleted
551// from the program to update the AST.  If you don't use this, you would have
552// dangling pointers to deleted instructions.
553//
554void AliasSetTracker::deleteValue(Value *PtrVal) {
555  // If this is a call instruction, remove the callsite from the appropriate
556  // AliasSet (if present).
557  if (Instruction *Inst = dyn_cast<Instruction>(PtrVal)) {
558    if (Inst->mayReadOrWriteMemory()) {
559      // Scan all the alias sets to see if this call site is contained.
560      for (iterator I = begin(), E = end(); I != E;) {
561        iterator Cur = I++;
562        if (!Cur->Forward)
563          Cur->removeUnknownInst(*this, Inst);
564      }
565    }
566  }
567
568  // First, look up the PointerRec for this pointer.
569  PointerMapType::iterator I = PointerMap.find_as(PtrVal);
570  if (I == PointerMap.end()) return;  // Noop
571
572  // If we found one, remove the pointer from the alias set it is in.
573  AliasSet::PointerRec *PtrValEnt = I->second;
574  AliasSet *AS = PtrValEnt->getAliasSet(*this);
575
576  // Unlink and delete from the list of values.
577  PtrValEnt->eraseFromList();
578
579  // Stop using the alias set.
580  AS->dropRef(*this);
581
582  PointerMap.erase(I);
583}
584
585// copyValue - This method should be used whenever a preexisting value in the
586// program is copied or cloned, introducing a new value.  Note that it is ok for
587// clients that use this method to introduce the same value multiple times: if
588// the tracker already knows about a value, it will ignore the request.
589//
590void AliasSetTracker::copyValue(Value *From, Value *To) {
591  // First, look up the PointerRec for this pointer.
592  PointerMapType::iterator I = PointerMap.find_as(From);
593  if (I == PointerMap.end())
594    return;  // Noop
595  assert(I->second->hasAliasSet() && "Dead entry?");
596
597  AliasSet::PointerRec &Entry = getEntryFor(To);
598  if (Entry.hasAliasSet()) return;    // Already in the tracker!
599
600  // Add it to the alias set it aliases...
601  I = PointerMap.find_as(From);
602  AliasSet *AS = I->second->getAliasSet(*this);
603  AS->addPointer(*this, Entry, I->second->getSize(),
604                 I->second->getAAInfo(),
605                 true);
606}
607
608
609
610//===----------------------------------------------------------------------===//
611//               AliasSet/AliasSetTracker Printing Support
612//===----------------------------------------------------------------------===//
613
614void AliasSet::print(raw_ostream &OS) const {
615  OS << "  AliasSet[" << (const void*)this << ", " << RefCount << "] ";
616  OS << (Alias == SetMustAlias ? "must" : "may") << " alias, ";
617  switch (Access) {
618  case NoAccess:     OS << "No access "; break;
619  case RefAccess:    OS << "Ref       "; break;
620  case ModAccess:    OS << "Mod       "; break;
621  case ModRefAccess: OS << "Mod/Ref   "; break;
622  default: llvm_unreachable("Bad value for Access!");
623  }
624  if (isVolatile()) OS << "[volatile] ";
625  if (Forward)
626    OS << " forwarding to " << (void*)Forward;
627
628
629  if (!empty()) {
630    OS << "Pointers: ";
631    for (iterator I = begin(), E = end(); I != E; ++I) {
632      if (I != begin()) OS << ", ";
633      I.getPointer()->printAsOperand(OS << "(");
634      OS << ", " << I.getSize() << ")";
635    }
636  }
637  if (!UnknownInsts.empty()) {
638    OS << "\n    " << UnknownInsts.size() << " Unknown instructions: ";
639    for (unsigned i = 0, e = UnknownInsts.size(); i != e; ++i) {
640      if (i) OS << ", ";
641      UnknownInsts[i]->printAsOperand(OS);
642    }
643  }
644  OS << "\n";
645}
646
647void AliasSetTracker::print(raw_ostream &OS) const {
648  OS << "Alias Set Tracker: " << AliasSets.size() << " alias sets for "
649     << PointerMap.size() << " pointer values.\n";
650  for (const AliasSet &AS : *this)
651    AS.print(OS);
652  OS << "\n";
653}
654
655#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
656LLVM_DUMP_METHOD void AliasSet::dump() const { print(dbgs()); }
657LLVM_DUMP_METHOD void AliasSetTracker::dump() const { print(dbgs()); }
658#endif
659
660//===----------------------------------------------------------------------===//
661//                     ASTCallbackVH Class Implementation
662//===----------------------------------------------------------------------===//
663
664void AliasSetTracker::ASTCallbackVH::deleted() {
665  assert(AST && "ASTCallbackVH called with a null AliasSetTracker!");
666  AST->deleteValue(getValPtr());
667  // this now dangles!
668}
669
670void AliasSetTracker::ASTCallbackVH::allUsesReplacedWith(Value *V) {
671  AST->copyValue(getValPtr(), V);
672}
673
674AliasSetTracker::ASTCallbackVH::ASTCallbackVH(Value *V, AliasSetTracker *ast)
675  : CallbackVH(V), AST(ast) {}
676
677AliasSetTracker::ASTCallbackVH &
678AliasSetTracker::ASTCallbackVH::operator=(Value *V) {
679  return *this = ASTCallbackVH(V, AST);
680}
681
682//===----------------------------------------------------------------------===//
683//                            AliasSetPrinter Pass
684//===----------------------------------------------------------------------===//
685
686namespace {
687  class AliasSetPrinter : public FunctionPass {
688    AliasSetTracker *Tracker;
689  public:
690    static char ID; // Pass identification, replacement for typeid
691    AliasSetPrinter() : FunctionPass(ID) {
692      initializeAliasSetPrinterPass(*PassRegistry::getPassRegistry());
693    }
694
695    void getAnalysisUsage(AnalysisUsage &AU) const override {
696      AU.setPreservesAll();
697      AU.addRequired<AAResultsWrapperPass>();
698    }
699
700    bool runOnFunction(Function &F) override {
701      auto &AAWP = getAnalysis<AAResultsWrapperPass>();
702      Tracker = new AliasSetTracker(AAWP.getAAResults());
703
704      for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
705        Tracker->add(&*I);
706      Tracker->print(errs());
707      delete Tracker;
708      return false;
709    }
710  };
711}
712
713char AliasSetPrinter::ID = 0;
714INITIALIZE_PASS_BEGIN(AliasSetPrinter, "print-alias-sets",
715                "Alias Set Printer", false, true)
716INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
717INITIALIZE_PASS_END(AliasSetPrinter, "print-alias-sets",
718                "Alias Set Printer", false, true)
719