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Value.cpp
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1 //===-- Value.cpp - Implement the Value class -----------------------------===//
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 Value, ValueHandle, and User classes.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/IR/Value.h"
15 #include "LLVMContextImpl.h"
16 #include "llvm/ADT/DenseMap.h"
17 #include "llvm/ADT/SmallString.h"
18 #include "llvm/IR/Constant.h"
19 #include "llvm/IR/Constants.h"
20 #include "llvm/IR/DerivedTypes.h"
21 #include "llvm/IR/InstrTypes.h"
22 #include "llvm/IR/Instructions.h"
23 #include "llvm/IR/Module.h"
24 #include "llvm/IR/Operator.h"
26 #include "llvm/Support/Debug.h"
32 #include <algorithm>
33 using namespace llvm;
34 
35 //===----------------------------------------------------------------------===//
36 // Value Class
37 //===----------------------------------------------------------------------===//
38 
39 static inline Type *checkType(Type *Ty) {
40  assert(Ty && "Value defined with a null type: Error!");
41  return const_cast<Type*>(Ty);
42 }
43 
44 Value::Value(Type *ty, unsigned scid)
45  : SubclassID(scid), HasValueHandle(0),
46  SubclassOptionalData(0), SubclassData(0), VTy((Type*)checkType(ty)),
47  UseList(0), Name(0) {
48  // FIXME: Why isn't this in the subclass gunk??
49  // Note, we cannot call isa<CallInst> before the CallInst has been
50  // constructed.
51  if (SubclassID == Instruction::Call || SubclassID == Instruction::Invoke)
52  assert((VTy->isFirstClassType() || VTy->isVoidTy() || VTy->isStructTy()) &&
53  "invalid CallInst type!");
54  else if (SubclassID != BasicBlockVal &&
55  (SubclassID < ConstantFirstVal || SubclassID > ConstantLastVal))
56  assert((VTy->isFirstClassType() || VTy->isVoidTy()) &&
57  "Cannot create non-first-class values except for constants!");
58 }
59 
61  // Notify all ValueHandles (if present) that this value is going away.
62  if (HasValueHandle)
64 
65 #ifndef NDEBUG // Only in -g mode...
66  // Check to make sure that there are no uses of this value that are still
67  // around when the value is destroyed. If there are, then we have a dangling
68  // reference and something is wrong. This code is here to print out what is
69  // still being referenced. The value in question should be printed as
70  // a <badref>
71  //
72  if (!use_empty()) {
73  dbgs() << "While deleting: " << *VTy << " %" << getName() << "\n";
74  for (use_iterator I = use_begin(), E = use_end(); I != E; ++I)
75  dbgs() << "Use still stuck around after Def is destroyed:"
76  << **I << "\n";
77  }
78 #endif
79  assert(use_empty() && "Uses remain when a value is destroyed!");
80 
81  // If this value is named, destroy the name. This should not be in a symtab
82  // at this point.
83  if (Name && SubclassID != MDStringVal)
84  Name->Destroy();
85 
86  // There should be no uses of this object anymore, remove it.
88 }
89 
90 /// hasNUses - Return true if this Value has exactly N users.
91 ///
92 bool Value::hasNUses(unsigned N) const {
93  const_use_iterator UI = use_begin(), E = use_end();
94 
95  for (; N; --N, ++UI)
96  if (UI == E) return false; // Too few.
97  return UI == E;
98 }
99 
100 /// hasNUsesOrMore - Return true if this value has N users or more. This is
101 /// logically equivalent to getNumUses() >= N.
102 ///
103 bool Value::hasNUsesOrMore(unsigned N) const {
104  const_use_iterator UI = use_begin(), E = use_end();
105 
106  for (; N; --N, ++UI)
107  if (UI == E) return false; // Too few.
108 
109  return true;
110 }
111 
112 /// isUsedInBasicBlock - Return true if this value is used in the specified
113 /// basic block.
114 bool Value::isUsedInBasicBlock(const BasicBlock *BB) const {
115  // This can be computed either by scanning the instructions in BB, or by
116  // scanning the use list of this Value. Both lists can be very long, but
117  // usually one is quite short.
118  //
119  // Scan both lists simultaneously until one is exhausted. This limits the
120  // search to the shorter list.
121  BasicBlock::const_iterator BI = BB->begin(), BE = BB->end();
122  const_use_iterator UI = use_begin(), UE = use_end();
123  for (; BI != BE && UI != UE; ++BI, ++UI) {
124  // Scan basic block: Check if this Value is used by the instruction at BI.
125  if (std::find(BI->op_begin(), BI->op_end(), this) != BI->op_end())
126  return true;
127  // Scan use list: Check if the use at UI is in BB.
128  const Instruction *User = dyn_cast<Instruction>(*UI);
129  if (User && User->getParent() == BB)
130  return true;
131  }
132  return false;
133 }
134 
135 
136 /// getNumUses - This method computes the number of uses of this Value. This
137 /// is a linear time operation. Use hasOneUse or hasNUses to check for specific
138 /// values.
139 unsigned Value::getNumUses() const {
140  return (unsigned)std::distance(use_begin(), use_end());
141 }
142 
143 static bool getSymTab(Value *V, ValueSymbolTable *&ST) {
144  ST = 0;
145  if (Instruction *I = dyn_cast<Instruction>(V)) {
146  if (BasicBlock *P = I->getParent())
147  if (Function *PP = P->getParent())
148  ST = &PP->getValueSymbolTable();
149  } else if (BasicBlock *BB = dyn_cast<BasicBlock>(V)) {
150  if (Function *P = BB->getParent())
151  ST = &P->getValueSymbolTable();
152  } else if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
153  if (Module *P = GV->getParent())
154  ST = &P->getValueSymbolTable();
155  } else if (Argument *A = dyn_cast<Argument>(V)) {
156  if (Function *P = A->getParent())
157  ST = &P->getValueSymbolTable();
158  } else if (isa<MDString>(V))
159  return true;
160  else {
161  assert(isa<Constant>(V) && "Unknown value type!");
162  return true; // no name is setable for this.
163  }
164  return false;
165 }
166 
168  // Make sure the empty string is still a C string. For historical reasons,
169  // some clients want to call .data() on the result and expect it to be null
170  // terminated.
171  if (!Name) return StringRef("", 0);
172  return Name->getKey();
173 }
174 
175 void Value::setName(const Twine &NewName) {
176  assert(SubclassID != MDStringVal &&
177  "Cannot set the name of MDString with this method!");
178 
179  // Fast path for common IRBuilder case of setName("") when there is no name.
180  if (NewName.isTriviallyEmpty() && !hasName())
181  return;
182 
183  SmallString<256> NameData;
184  StringRef NameRef = NewName.toStringRef(NameData);
185 
186  // Name isn't changing?
187  if (getName() == NameRef)
188  return;
189 
190  assert(!getType()->isVoidTy() && "Cannot assign a name to void values!");
191 
192  // Get the symbol table to update for this object.
194  if (getSymTab(this, ST))
195  return; // Cannot set a name on this value (e.g. constant).
196 
197  if (Function *F = dyn_cast<Function>(this))
199 
200  if (!ST) { // No symbol table to update? Just do the change.
201  if (NameRef.empty()) {
202  // Free the name for this value.
203  Name->Destroy();
204  Name = 0;
205  return;
206  }
207 
208  if (Name)
209  Name->Destroy();
210 
211  // NOTE: Could optimize for the case the name is shrinking to not deallocate
212  // then reallocated.
213 
214  // Create the new name.
215  Name = ValueName::Create(NameRef.begin(), NameRef.end());
216  Name->setValue(this);
217  return;
218  }
219 
220  // NOTE: Could optimize for the case the name is shrinking to not deallocate
221  // then reallocated.
222  if (hasName()) {
223  // Remove old name.
224  ST->removeValueName(Name);
225  Name->Destroy();
226  Name = 0;
227 
228  if (NameRef.empty())
229  return;
230  }
231 
232  // Name is changing to something new.
233  Name = ST->createValueName(NameRef, this);
234 }
235 
236 
237 /// takeName - transfer the name from V to this value, setting V's name to
238 /// empty. It is an error to call V->takeName(V).
240  assert(SubclassID != MDStringVal && "Cannot take the name of an MDString!");
241 
242  ValueSymbolTable *ST = 0;
243  // If this value has a name, drop it.
244  if (hasName()) {
245  // Get the symtab this is in.
246  if (getSymTab(this, ST)) {
247  // We can't set a name on this value, but we need to clear V's name if
248  // it has one.
249  if (V->hasName()) V->setName("");
250  return; // Cannot set a name on this value (e.g. constant).
251  }
252 
253  // Remove old name.
254  if (ST)
255  ST->removeValueName(Name);
256  Name->Destroy();
257  Name = 0;
258  }
259 
260  // Now we know that this has no name.
261 
262  // If V has no name either, we're done.
263  if (!V->hasName()) return;
264 
265  // Get this's symtab if we didn't before.
266  if (!ST) {
267  if (getSymTab(this, ST)) {
268  // Clear V's name.
269  V->setName("");
270  return; // Cannot set a name on this value (e.g. constant).
271  }
272  }
273 
274  // Get V's ST, this should always succed, because V has a name.
275  ValueSymbolTable *VST;
276  bool Failure = getSymTab(V, VST);
277  assert(!Failure && "V has a name, so it should have a ST!"); (void)Failure;
278 
279  // If these values are both in the same symtab, we can do this very fast.
280  // This works even if both values have no symtab yet.
281  if (ST == VST) {
282  // Take the name!
283  Name = V->Name;
284  V->Name = 0;
285  Name->setValue(this);
286  return;
287  }
288 
289  // Otherwise, things are slightly more complex. Remove V's name from VST and
290  // then reinsert it into ST.
291 
292  if (VST)
293  VST->removeValueName(V->Name);
294  Name = V->Name;
295  V->Name = 0;
296  Name->setValue(this);
297 
298  if (ST)
299  ST->reinsertValue(this);
300 }
301 
302 
304  assert(New && "Value::replaceAllUsesWith(<null>) is invalid!");
305  assert(New != this && "this->replaceAllUsesWith(this) is NOT valid!");
306  assert(New->getType() == getType() &&
307  "replaceAllUses of value with new value of different type!");
308 
309  // Notify all ValueHandles (if present) that this value is going away.
310  if (HasValueHandle)
312 
313  while (!use_empty()) {
314  Use &U = *UseList;
315  // Must handle Constants specially, we cannot call replaceUsesOfWith on a
316  // constant because they are uniqued.
317  if (Constant *C = dyn_cast<Constant>(U.getUser())) {
318  if (!isa<GlobalValue>(C)) {
319  C->replaceUsesOfWithOnConstant(this, New, &U);
320  continue;
321  }
322  }
323 
324  U.set(New);
325  }
326 
327  if (BasicBlock *BB = dyn_cast<BasicBlock>(this))
328  BB->replaceSuccessorsPhiUsesWith(cast<BasicBlock>(New));
329 }
330 
331 namespace {
332 // Various metrics for how much to strip off of pointers.
334  PSK_ZeroIndices,
335  PSK_ZeroIndicesAndAliases,
336  PSK_InBoundsConstantIndices,
337  PSK_InBounds
338 };
339 
340 template <PointerStripKind StripKind>
341 static Value *stripPointerCastsAndOffsets(Value *V) {
342  if (!V->getType()->isPointerTy())
343  return V;
344 
345  // Even though we don't look through PHI nodes, we could be called on an
346  // instruction in an unreachable block, which may be on a cycle.
347  SmallPtrSet<Value *, 4> Visited;
348 
349  Visited.insert(V);
350  do {
351  if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
352  switch (StripKind) {
353  case PSK_ZeroIndicesAndAliases:
354  case PSK_ZeroIndices:
355  if (!GEP->hasAllZeroIndices())
356  return V;
357  break;
358  case PSK_InBoundsConstantIndices:
359  if (!GEP->hasAllConstantIndices())
360  return V;
361  // fallthrough
362  case PSK_InBounds:
363  if (!GEP->isInBounds())
364  return V;
365  break;
366  }
367  V = GEP->getPointerOperand();
368  } else if (Operator::getOpcode(V) == Instruction::BitCast ||
369  Operator::getOpcode(V) == Instruction::AddrSpaceCast) {
370  V = cast<Operator>(V)->getOperand(0);
371  } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
372  if (StripKind == PSK_ZeroIndices || GA->mayBeOverridden())
373  return V;
374  V = GA->getAliasee();
375  } else {
376  return V;
377  }
378  assert(V->getType()->isPointerTy() && "Unexpected operand type!");
379  } while (Visited.insert(V));
380 
381  return V;
382 }
383 } // namespace
384 
386  return stripPointerCastsAndOffsets<PSK_ZeroIndicesAndAliases>(this);
387 }
388 
390  return stripPointerCastsAndOffsets<PSK_ZeroIndices>(this);
391 }
392 
394  return stripPointerCastsAndOffsets<PSK_InBoundsConstantIndices>(this);
395 }
396 
398  APInt &Offset) {
399  if (!getType()->isPointerTy())
400  return this;
401 
402  assert(Offset.getBitWidth() == DL.getPointerSizeInBits(cast<PointerType>(
403  getType())->getAddressSpace()) &&
404  "The offset must have exactly as many bits as our pointer.");
405 
406  // Even though we don't look through PHI nodes, we could be called on an
407  // instruction in an unreachable block, which may be on a cycle.
408  SmallPtrSet<Value *, 4> Visited;
409  Visited.insert(this);
410  Value *V = this;
411  do {
412  if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
413  if (!GEP->isInBounds())
414  return V;
415  APInt GEPOffset(Offset);
416  if (!GEP->accumulateConstantOffset(DL, GEPOffset))
417  return V;
418  Offset = GEPOffset;
419  V = GEP->getPointerOperand();
420  } else if (Operator::getOpcode(V) == Instruction::BitCast) {
421  V = cast<Operator>(V)->getOperand(0);
422  } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
423  V = GA->getAliasee();
424  } else {
425  return V;
426  }
427  assert(V->getType()->isPointerTy() && "Unexpected operand type!");
428  } while (Visited.insert(V));
429 
430  return V;
431 }
432 
434  return stripPointerCastsAndOffsets<PSK_InBounds>(this);
435 }
436 
437 /// isDereferenceablePointer - Test if this value is always a pointer to
438 /// allocated and suitably aligned memory for a simple load or store.
439 static bool isDereferenceablePointer(const Value *V,
441  // Note that it is not safe to speculate into a malloc'd region because
442  // malloc may return null.
443  // It's also not always safe to follow a bitcast, for example:
444  // bitcast i8* (alloca i8) to i32*
445  // would result in a 4-byte load from a 1-byte alloca. Some cases could
446  // be handled using DataLayout to check sizes and alignments though.
447 
448  // These are obviously ok.
449  if (isa<AllocaInst>(V)) return true;
450 
451  // Global variables which can't collapse to null are ok.
452  if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
453  return !GV->hasExternalWeakLinkage();
454 
455  // byval arguments are ok.
456  if (const Argument *A = dyn_cast<Argument>(V))
457  return A->hasByValAttr();
458 
459  // For GEPs, determine if the indexing lands within the allocated object.
460  if (const GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
461  // Conservatively require that the base pointer be fully dereferenceable.
462  if (!Visited.insert(GEP->getOperand(0)))
463  return false;
464  if (!isDereferenceablePointer(GEP->getOperand(0), Visited))
465  return false;
466  // Check the indices.
468  for (User::const_op_iterator I = GEP->op_begin()+1,
469  E = GEP->op_end(); I != E; ++I) {
470  Value *Index = *I;
471  Type *Ty = *GTI++;
472  // Struct indices can't be out of bounds.
473  if (isa<StructType>(Ty))
474  continue;
475  ConstantInt *CI = dyn_cast<ConstantInt>(Index);
476  if (!CI)
477  return false;
478  // Zero is always ok.
479  if (CI->isZero())
480  continue;
481  // Check to see that it's within the bounds of an array.
482  ArrayType *ATy = dyn_cast<ArrayType>(Ty);
483  if (!ATy)
484  return false;
485  if (CI->getValue().getActiveBits() > 64)
486  return false;
487  if (CI->getZExtValue() >= ATy->getNumElements())
488  return false;
489  }
490  // Indices check out; this is dereferenceable.
491  return true;
492  }
493 
494  // If we don't know, assume the worst.
495  return false;
496 }
497 
498 /// isDereferenceablePointer - Test if this value is always a pointer to
499 /// allocated and suitably aligned memory for a simple load or store.
502  return ::isDereferenceablePointer(this, Visited);
503 }
504 
505 /// DoPHITranslation - If this value is a PHI node with CurBB as its parent,
506 /// return the value in the PHI node corresponding to PredBB. If not, return
507 /// ourself. This is useful if you want to know the value something has in a
508 /// predecessor block.
510  const BasicBlock *PredBB) {
511  PHINode *PN = dyn_cast<PHINode>(this);
512  if (PN && PN->getParent() == CurBB)
513  return PN->getIncomingValueForBlock(PredBB);
514  return this;
515 }
516 
517 LLVMContext &Value::getContext() const { return VTy->getContext(); }
518 
519 //===----------------------------------------------------------------------===//
520 // ValueHandleBase Class
521 //===----------------------------------------------------------------------===//
522 
523 /// AddToExistingUseList - Add this ValueHandle to the use list for VP, where
524 /// List is known to point into the existing use list.
525 void ValueHandleBase::AddToExistingUseList(ValueHandleBase **List) {
526  assert(List && "Handle list is null?");
527 
528  // Splice ourselves into the list.
529  Next = *List;
530  *List = this;
531  setPrevPtr(List);
532  if (Next) {
533  Next->setPrevPtr(&Next);
534  assert(VP.getPointer() == Next->VP.getPointer() && "Added to wrong list?");
535  }
536 }
537 
538 void ValueHandleBase::AddToExistingUseListAfter(ValueHandleBase *List) {
539  assert(List && "Must insert after existing node");
540 
541  Next = List->Next;
542  setPrevPtr(&List->Next);
543  List->Next = this;
544  if (Next)
545  Next->setPrevPtr(&Next);
546 }
547 
548 /// AddToUseList - Add this ValueHandle to the use list for VP.
549 void ValueHandleBase::AddToUseList() {
550  assert(VP.getPointer() && "Null pointer doesn't have a use list!");
551 
552  LLVMContextImpl *pImpl = VP.getPointer()->getContext().pImpl;
553 
554  if (VP.getPointer()->HasValueHandle) {
555  // If this value already has a ValueHandle, then it must be in the
556  // ValueHandles map already.
557  ValueHandleBase *&Entry = pImpl->ValueHandles[VP.getPointer()];
558  assert(Entry != 0 && "Value doesn't have any handles?");
559  AddToExistingUseList(&Entry);
560  return;
561  }
562 
563  // Ok, it doesn't have any handles yet, so we must insert it into the
564  // DenseMap. However, doing this insertion could cause the DenseMap to
565  // reallocate itself, which would invalidate all of the PrevP pointers that
566  // point into the old table. Handle this by checking for reallocation and
567  // updating the stale pointers only if needed.
568  DenseMap<Value*, ValueHandleBase*> &Handles = pImpl->ValueHandles;
569  const void *OldBucketPtr = Handles.getPointerIntoBucketsArray();
570 
571  ValueHandleBase *&Entry = Handles[VP.getPointer()];
572  assert(Entry == 0 && "Value really did already have handles?");
573  AddToExistingUseList(&Entry);
574  VP.getPointer()->HasValueHandle = true;
575 
576  // If reallocation didn't happen or if this was the first insertion, don't
577  // walk the table.
578  if (Handles.isPointerIntoBucketsArray(OldBucketPtr) ||
579  Handles.size() == 1) {
580  return;
581  }
582 
583  // Okay, reallocation did happen. Fix the Prev Pointers.
585  E = Handles.end(); I != E; ++I) {
586  assert(I->second && I->first == I->second->VP.getPointer() &&
587  "List invariant broken!");
588  I->second->setPrevPtr(&I->second);
589  }
590 }
591 
592 /// RemoveFromUseList - Remove this ValueHandle from its current use list.
593 void ValueHandleBase::RemoveFromUseList() {
594  assert(VP.getPointer() && VP.getPointer()->HasValueHandle &&
595  "Pointer doesn't have a use list!");
596 
597  // Unlink this from its use list.
598  ValueHandleBase **PrevPtr = getPrevPtr();
599  assert(*PrevPtr == this && "List invariant broken");
600 
601  *PrevPtr = Next;
602  if (Next) {
603  assert(Next->getPrevPtr() == &Next && "List invariant broken");
604  Next->setPrevPtr(PrevPtr);
605  return;
606  }
607 
608  // If the Next pointer was null, then it is possible that this was the last
609  // ValueHandle watching VP. If so, delete its entry from the ValueHandles
610  // map.
611  LLVMContextImpl *pImpl = VP.getPointer()->getContext().pImpl;
613  if (Handles.isPointerIntoBucketsArray(PrevPtr)) {
614  Handles.erase(VP.getPointer());
615  VP.getPointer()->HasValueHandle = false;
616  }
617 }
618 
619 
621  assert(V->HasValueHandle && "Should only be called if ValueHandles present");
622 
623  // Get the linked list base, which is guaranteed to exist since the
624  // HasValueHandle flag is set.
625  LLVMContextImpl *pImpl = V->getContext().pImpl;
626  ValueHandleBase *Entry = pImpl->ValueHandles[V];
627  assert(Entry && "Value bit set but no entries exist");
628 
629  // We use a local ValueHandleBase as an iterator so that ValueHandles can add
630  // and remove themselves from the list without breaking our iteration. This
631  // is not really an AssertingVH; we just have to give ValueHandleBase a kind.
632  // Note that we deliberately do not the support the case when dropping a value
633  // handle results in a new value handle being permanently added to the list
634  // (as might occur in theory for CallbackVH's): the new value handle will not
635  // be processed and the checking code will mete out righteous punishment if
636  // the handle is still present once we have finished processing all the other
637  // value handles (it is fine to momentarily add then remove a value handle).
638  for (ValueHandleBase Iterator(Assert, *Entry); Entry; Entry = Iterator.Next) {
639  Iterator.RemoveFromUseList();
640  Iterator.AddToExistingUseListAfter(Entry);
641  assert(Entry->Next == &Iterator && "Loop invariant broken.");
642 
643  switch (Entry->getKind()) {
644  case Assert:
645  break;
646  case Tracking:
647  // Mark that this value has been deleted by setting it to an invalid Value
648  // pointer.
649  Entry->operator=(DenseMapInfo<Value *>::getTombstoneKey());
650  break;
651  case Weak:
652  // Weak just goes to null, which will unlink it from the list.
653  Entry->operator=(0);
654  break;
655  case Callback:
656  // Forward to the subclass's implementation.
657  static_cast<CallbackVH*>(Entry)->deleted();
658  break;
659  }
660  }
661 
662  // All callbacks, weak references, and assertingVHs should be dropped by now.
663  if (V->HasValueHandle) {
664 #ifndef NDEBUG // Only in +Asserts mode...
665  dbgs() << "While deleting: " << *V->getType() << " %" << V->getName()
666  << "\n";
667  if (pImpl->ValueHandles[V]->getKind() == Assert)
668  llvm_unreachable("An asserting value handle still pointed to this"
669  " value!");
670 
671 #endif
672  llvm_unreachable("All references to V were not removed?");
673  }
674 }
675 
676 
678  assert(Old->HasValueHandle &&"Should only be called if ValueHandles present");
679  assert(Old != New && "Changing value into itself!");
680 
681  // Get the linked list base, which is guaranteed to exist since the
682  // HasValueHandle flag is set.
683  LLVMContextImpl *pImpl = Old->getContext().pImpl;
684  ValueHandleBase *Entry = pImpl->ValueHandles[Old];
685 
686  assert(Entry && "Value bit set but no entries exist");
687 
688  // We use a local ValueHandleBase as an iterator so that
689  // ValueHandles can add and remove themselves from the list without
690  // breaking our iteration. This is not really an AssertingVH; we
691  // just have to give ValueHandleBase some kind.
692  for (ValueHandleBase Iterator(Assert, *Entry); Entry; Entry = Iterator.Next) {
693  Iterator.RemoveFromUseList();
694  Iterator.AddToExistingUseListAfter(Entry);
695  assert(Entry->Next == &Iterator && "Loop invariant broken.");
696 
697  switch (Entry->getKind()) {
698  case Assert:
699  // Asserting handle does not follow RAUW implicitly.
700  break;
701  case Tracking:
702  // Tracking goes to new value like a WeakVH. Note that this may make it
703  // something incompatible with its templated type. We don't want to have a
704  // virtual (or inline) interface to handle this though, so instead we make
705  // the TrackingVH accessors guarantee that a client never sees this value.
706 
707  // FALLTHROUGH
708  case Weak:
709  // Weak goes to the new value, which will unlink it from Old's list.
710  Entry->operator=(New);
711  break;
712  case Callback:
713  // Forward to the subclass's implementation.
714  static_cast<CallbackVH*>(Entry)->allUsesReplacedWith(New);
715  break;
716  }
717  }
718 
719 #ifndef NDEBUG
720  // If any new tracking or weak value handles were added while processing the
721  // list, then complain about it now.
722  if (Old->HasValueHandle)
723  for (Entry = pImpl->ValueHandles[Old]; Entry; Entry = Entry->Next)
724  switch (Entry->getKind()) {
725  case Tracking:
726  case Weak:
727  dbgs() << "After RAUW from " << *Old->getType() << " %"
728  << Old->getName() << " to " << *New->getType() << " %"
729  << New->getName() << "\n";
730  llvm_unreachable("A tracking or weak value handle still pointed to the"
731  " old value!\n");
732  default:
733  break;
734  }
735 #endif
736 }
737 
738 // Pin the vtable to this file.
739 void CallbackVH::anchor() {}
bool isPointerIntoBucketsArray(const void *Ptr) const
Definition: DenseMap.h:238
use_iterator use_end()
Definition: Value.h:152
static void ValueIsDeleted(Value *V)
Definition: Value.cpp:620
Value * stripInBoundsConstantOffsets()
Strips off unneeded pointer casts and all-constant GEPs from the specified value, returning the origi...
Definition: Value.cpp:393
LLVM Argument representation.
Definition: Argument.h:35
static bool isDereferenceablePointer(const Value *V, SmallPtrSet< const Value *, 32 > &Visited)
Definition: Value.cpp:439
bool hasName() const
Definition: Value.h:117
The main container class for the LLVM Intermediate Representation.
Definition: Module.h:112
void setValue(const ValueTy &V)
Definition: StringMap.h:135
bool hasNUses(unsigned N) const
Definition: Value.cpp:92
enable_if_c<!is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:266
bool insert(PtrType Ptr)
Definition: SmallPtrSet.h:253
F(f)
StringRef getName() const
Definition: Value.cpp:167
iterator begin()
Definition: BasicBlock.h:193
static void removeGarbageObject(void *Object)
Definition: LeakDetector.h:47
static Type * checkType(Type *Ty)
Definition: Value.cpp:39
const APInt & getValue() const
Return the constant's value.
Definition: Constants.h:105
#define llvm_unreachable(msg)
Definition: Use.h:60
void setName(const Twine &Name)
Definition: Value.cpp:175
Value * stripAndAccumulateInBoundsConstantOffsets(const DataLayout &DL, APInt &Offset)
Strips like stripInBoundsConstantOffsets but also accumulates the constant offset stripped...
Definition: Value.cpp:397
uint64_t getZExtValue() const
Return the zero extended value.
Definition: Constants.h:116
void Destroy(AllocatorTy &Allocator)
Definition: StringMap.h:217
LLVMContext & getContext() const
getContext - Return the LLVMContext in which this type was uniqued.
Definition: Type.h:128
bool isFirstClassType() const
Definition: Type.h:251
unsigned getActiveBits() const
Compute the number of active bits in the value.
Definition: APInt.h:1276
void replaceAllUsesWith(Value *V)
Definition: Value.cpp:303
static void ValueIsRAUWd(Value *Old, Value *New)
Definition: Value.cpp:677
const void * getPointerIntoBucketsArray() const
Definition: DenseMap.h:245
void takeName(Value *V)
Definition: Value.cpp:239
iterator begin() const
Definition: StringRef.h:97
Value * stripPointerCastsNoFollowAliases()
Strips off any unneeded pointer casts and all-zero GEPs from the specified value, returning the origi...
Definition: Value.cpp:389
#define P(N)
void set(Value *Val)
Definition: Value.h:356
LLVM Basic Block Representation.
Definition: BasicBlock.h:72
LLVM Constant Representation.
Definition: Constant.h:41
Value * stripInBoundsOffsets()
Strips off unneeded pointer casts and any in-bounds offsets from the specified value, returning the original pointer value.
Definition: Value.cpp:433
uint64_t getNumElements() const
Definition: DerivedTypes.h:348
unsigned getBitWidth() const
Return the number of bits in the APInt.
Definition: APInt.h:1252
ValueHandlesTy ValueHandles
User * getUser() const
Definition: Use.cpp:137
iterator end()
Definition: DenseMap.h:57
bool isPointerTy() const
Definition: Type.h:220
IntrinsicIDCacheTy IntrinsicIDCache
LLVMContext & getContext() const
All values hold a context through their type.
Definition: Value.cpp:517
bool isUsedInBasicBlock(const BasicBlock *BB) const
Definition: Value.cpp:114
LLVMContextImpl *const pImpl
Definition: LLVMContext.h:39
Class for constant integers.
Definition: Constants.h:51
Value * DoPHITranslation(const BasicBlock *CurBB, const BasicBlock *PredBB)
Definition: Value.cpp:509
iterator end()
Definition: BasicBlock.h:195
Type * getType() const
Definition: Value.h:111
bool erase(const KeyT &Val)
Definition: DenseMap.h:190
StringRef toStringRef(SmallVectorImpl< char > &Out) const
Definition: Twine.cpp:31
PointerStripKind
Definition: Value.cpp:333
Value * stripPointerCasts()
Strips off any unneeded pointer casts, all-zero GEPs and aliases from the specified value...
Definition: Value.cpp:385
static StringMapEntry * Create(const char *KeyStart, const char *KeyEnd, AllocatorTy &Allocator, InitType InitVal)
Definition: StringMap.h:147
bool isZero() const
Definition: Constants.h:160
raw_ostream & dbgs()
dbgs - Return a circular-buffered debug stream.
Definition: Debug.cpp:101
Class for arbitrary precision integers.
Definition: APInt.h:75
StringRef getKey() const
Definition: StringMap.h:128
Value * getIncomingValueForBlock(const BasicBlock *BB) const
unsigned size() const
Definition: DenseMap.h:70
iterator begin()
Definition: DenseMap.h:53
bool isStructTy() const
Definition: Type.h:212
unsigned getOpcode() const
Definition: Operator.h:51
bool isDereferenceablePointer() const
Definition: Value.cpp:500
use_iterator use_begin()
Definition: Value.h:150
#define I(x, y, z)
Definition: MD5.cpp:54
#define N
unsigned getPointerSizeInBits(unsigned AS=0) const
Definition: DataLayout.h:271
static bool getSymTab(Value *V, ValueSymbolTable *&ST)
Definition: Value.cpp:143
bool hasNUsesOrMore(unsigned N) const
Definition: Value.cpp:103
virtual ~Value()
Definition: Value.cpp:60
bool use_empty() const
Definition: Value.h:149
LLVM Value Representation.
Definition: Value.h:66
bool isTriviallyEmpty() const
Definition: Twine.h:387
iterator end() const
Definition: StringRef.h:99
unsigned getNumUses() const
Definition: Value.cpp:139
const BasicBlock * getParent() const
Definition: Instruction.h:52
bool isVoidTy() const
isVoidTy - Return true if this is 'void'.
Definition: Type.h:140
bool empty() const
empty - Check if the string is empty.
Definition: StringRef.h:110
gep_type_iterator gep_type_begin(const User *GEP)