1 //===-- Value.cpp - Implement the Value class -----------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the Value, ValueHandle, and User classes.
12 //===----------------------------------------------------------------------===//
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/ADT/SetVector.h"
19 #include "llvm/IR/CallSite.h"
20 #include "llvm/IR/Constant.h"
21 #include "llvm/IR/Constants.h"
22 #include "llvm/IR/DataLayout.h"
23 #include "llvm/IR/DerivedTypes.h"
24 #include "llvm/IR/DerivedUser.h"
25 #include "llvm/IR/GetElementPtrTypeIterator.h"
26 #include "llvm/IR/InstrTypes.h"
27 #include "llvm/IR/Instructions.h"
28 #include "llvm/IR/IntrinsicInst.h"
29 #include "llvm/IR/Module.h"
30 #include "llvm/IR/Operator.h"
31 #include "llvm/IR/Statepoint.h"
32 #include "llvm/IR/ValueHandle.h"
33 #include "llvm/IR/ValueSymbolTable.h"
34 #include "llvm/Support/Debug.h"
35 #include "llvm/Support/ErrorHandling.h"
36 #include "llvm/Support/ManagedStatic.h"
37 #include "llvm/Support/raw_ostream.h"
42 static cl::opt<unsigned> NonGlobalValueMaxNameSize(
43 "non-global-value-max-name-size", cl::Hidden, cl::init(1024),
44 cl::desc("Maximum size for the name of non-global values."));
46 //===----------------------------------------------------------------------===//
48 //===----------------------------------------------------------------------===//
49 static inline Type *checkType(Type *Ty) {
50 assert(Ty && "Value defined with a null type: Error!");
54 Value::Value(Type *ty, unsigned scid)
55 : VTy(checkType(ty)), UseList(nullptr), SubclassID(scid),
56 HasValueHandle(0), SubclassOptionalData(0), SubclassData(0),
57 NumUserOperands(0), IsUsedByMD(false), HasName(false) {
58 static_assert(ConstantFirstVal == 0, "!(SubclassID < ConstantFirstVal)");
59 // FIXME: Why isn't this in the subclass gunk??
60 // Note, we cannot call isa<CallInst> before the CallInst has been
62 if (SubclassID == Instruction::Call || SubclassID == Instruction::Invoke)
63 assert((VTy->isFirstClassType() || VTy->isVoidTy() || VTy->isStructTy()) &&
64 "invalid CallInst type!");
65 else if (SubclassID != BasicBlockVal &&
66 (/*SubclassID < ConstantFirstVal ||*/ SubclassID > ConstantLastVal))
67 assert((VTy->isFirstClassType() || VTy->isVoidTy()) &&
68 "Cannot create non-first-class values except for constants!");
69 static_assert(sizeof(Value) == 2 * sizeof(void *) + 2 * sizeof(unsigned),
74 // Notify all ValueHandles (if present) that this value is going away.
76 ValueHandleBase::ValueIsDeleted(this);
77 if (isUsedByMetadata())
78 ValueAsMetadata::handleDeletion(this);
80 #ifndef NDEBUG // Only in -g mode...
81 // Check to make sure that there are no uses of this value that are still
82 // around when the value is destroyed. If there are, then we have a dangling
83 // reference and something is wrong. This code is here to print out where
84 // the value is still being referenced.
87 dbgs() << "While deleting: " << *VTy << " %" << getName() << "\n";
88 for (auto *U : users())
89 dbgs() << "Use still stuck around after Def is destroyed:" << *U << "\n";
92 assert(use_empty() && "Uses remain when a value is destroyed!");
94 // If this value is named, destroy the name. This should not be in a symtab
99 void Value::deleteValue() {
100 switch (getValueID()) {
101 #define HANDLE_VALUE(Name) \
102 case Value::Name##Val: \
103 delete static_cast<Name *>(this); \
105 #define HANDLE_MEMORY_VALUE(Name) \
106 case Value::Name##Val: \
107 static_cast<DerivedUser *>(this)->DeleteValue( \
108 static_cast<DerivedUser *>(this)); \
110 #define HANDLE_INSTRUCTION(Name) /* nothing */
111 #include "llvm/IR/Value.def"
113 #define HANDLE_INST(N, OPC, CLASS) \
114 case Value::InstructionVal + Instruction::OPC: \
115 delete static_cast<CLASS *>(this); \
117 #define HANDLE_USER_INST(N, OPC, CLASS)
118 #include "llvm/IR/Instruction.def"
121 llvm_unreachable("attempting to delete unknown value kind");
125 void Value::destroyValueName() {
126 ValueName *Name = getValueName();
129 setValueName(nullptr);
132 bool Value::hasNUses(unsigned N) const {
133 const_use_iterator UI = use_begin(), E = use_end();
136 if (UI == E) return false; // Too few.
140 bool Value::hasNUsesOrMore(unsigned N) const {
141 const_use_iterator UI = use_begin(), E = use_end();
144 if (UI == E) return false; // Too few.
149 bool Value::isUsedInBasicBlock(const BasicBlock *BB) const {
150 // This can be computed either by scanning the instructions in BB, or by
151 // scanning the use list of this Value. Both lists can be very long, but
152 // usually one is quite short.
154 // Scan both lists simultaneously until one is exhausted. This limits the
155 // search to the shorter list.
156 BasicBlock::const_iterator BI = BB->begin(), BE = BB->end();
157 const_user_iterator UI = user_begin(), UE = user_end();
158 for (; BI != BE && UI != UE; ++BI, ++UI) {
159 // Scan basic block: Check if this Value is used by the instruction at BI.
160 if (is_contained(BI->operands(), this))
162 // Scan use list: Check if the use at UI is in BB.
163 const auto *User = dyn_cast<Instruction>(*UI);
164 if (User && User->getParent() == BB)
170 unsigned Value::getNumUses() const {
171 return (unsigned)std::distance(use_begin(), use_end());
174 static bool getSymTab(Value *V, ValueSymbolTable *&ST) {
176 if (Instruction *I = dyn_cast<Instruction>(V)) {
177 if (BasicBlock *P = I->getParent())
178 if (Function *PP = P->getParent())
179 ST = PP->getValueSymbolTable();
180 } else if (BasicBlock *BB = dyn_cast<BasicBlock>(V)) {
181 if (Function *P = BB->getParent())
182 ST = P->getValueSymbolTable();
183 } else if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
184 if (Module *P = GV->getParent())
185 ST = &P->getValueSymbolTable();
186 } else if (Argument *A = dyn_cast<Argument>(V)) {
187 if (Function *P = A->getParent())
188 ST = P->getValueSymbolTable();
190 assert(isa<Constant>(V) && "Unknown value type!");
191 return true; // no name is setable for this.
196 ValueName *Value::getValueName() const {
197 if (!HasName) return nullptr;
199 LLVMContext &Ctx = getContext();
200 auto I = Ctx.pImpl->ValueNames.find(this);
201 assert(I != Ctx.pImpl->ValueNames.end() &&
202 "No name entry found!");
207 void Value::setValueName(ValueName *VN) {
208 LLVMContext &Ctx = getContext();
210 assert(HasName == Ctx.pImpl->ValueNames.count(this) &&
211 "HasName bit out of sync!");
215 Ctx.pImpl->ValueNames.erase(this);
221 Ctx.pImpl->ValueNames[this] = VN;
224 StringRef Value::getName() const {
225 // Make sure the empty string is still a C string. For historical reasons,
226 // some clients want to call .data() on the result and expect it to be null
229 return StringRef("", 0);
230 return getValueName()->getKey();
233 void Value::setNameImpl(const Twine &NewName) {
234 // Fast-path: LLVMContext can be set to strip out non-GlobalValue names
235 if (getContext().shouldDiscardValueNames() && !isa<GlobalValue>(this))
238 // Fast path for common IRBuilder case of setName("") when there is no name.
239 if (NewName.isTriviallyEmpty() && !hasName())
242 SmallString<256> NameData;
243 StringRef NameRef = NewName.toStringRef(NameData);
244 assert(NameRef.find_first_of(0) == StringRef::npos &&
245 "Null bytes are not allowed in names");
247 // Name isn't changing?
248 if (getName() == NameRef)
251 // Cap the size of non-GlobalValue names.
252 if (NameRef.size() > NonGlobalValueMaxNameSize && !isa<GlobalValue>(this))
254 NameRef.substr(0, std::max(1u, (unsigned)NonGlobalValueMaxNameSize));
256 assert(!getType()->isVoidTy() && "Cannot assign a name to void values!");
258 // Get the symbol table to update for this object.
259 ValueSymbolTable *ST;
260 if (getSymTab(this, ST))
261 return; // Cannot set a name on this value (e.g. constant).
263 if (!ST) { // No symbol table to update? Just do the change.
264 if (NameRef.empty()) {
265 // Free the name for this value.
270 // NOTE: Could optimize for the case the name is shrinking to not deallocate
274 // Create the new name.
275 setValueName(ValueName::Create(NameRef));
276 getValueName()->setValue(this);
280 // NOTE: Could optimize for the case the name is shrinking to not deallocate
284 ST->removeValueName(getValueName());
291 // Name is changing to something new.
292 setValueName(ST->createValueName(NameRef, this));
295 void Value::setName(const Twine &NewName) {
296 setNameImpl(NewName);
297 if (Function *F = dyn_cast<Function>(this))
298 F->recalculateIntrinsicID();
301 void Value::takeName(Value *V) {
302 ValueSymbolTable *ST = nullptr;
303 // If this value has a name, drop it.
305 // Get the symtab this is in.
306 if (getSymTab(this, ST)) {
307 // We can't set a name on this value, but we need to clear V's name if
309 if (V->hasName()) V->setName("");
310 return; // Cannot set a name on this value (e.g. constant).
315 ST->removeValueName(getValueName());
319 // Now we know that this has no name.
321 // If V has no name either, we're done.
322 if (!V->hasName()) return;
324 // Get this's symtab if we didn't before.
326 if (getSymTab(this, ST)) {
329 return; // Cannot set a name on this value (e.g. constant).
333 // Get V's ST, this should always succed, because V has a name.
334 ValueSymbolTable *VST;
335 bool Failure = getSymTab(V, VST);
336 assert(!Failure && "V has a name, so it should have a ST!"); (void)Failure;
338 // If these values are both in the same symtab, we can do this very fast.
339 // This works even if both values have no symtab yet.
342 setValueName(V->getValueName());
343 V->setValueName(nullptr);
344 getValueName()->setValue(this);
348 // Otherwise, things are slightly more complex. Remove V's name from VST and
349 // then reinsert it into ST.
352 VST->removeValueName(V->getValueName());
353 setValueName(V->getValueName());
354 V->setValueName(nullptr);
355 getValueName()->setValue(this);
358 ST->reinsertValue(this);
361 void Value::assertModuleIsMaterializedImpl() const {
363 const GlobalValue *GV = dyn_cast<GlobalValue>(this);
366 const Module *M = GV->getParent();
369 assert(M->isMaterialized());
374 static bool contains(SmallPtrSetImpl<ConstantExpr *> &Cache, ConstantExpr *Expr,
376 if (!Cache.insert(Expr).second)
379 for (auto &O : Expr->operands()) {
382 auto *CE = dyn_cast<ConstantExpr>(O);
385 if (contains(Cache, CE, C))
391 static bool contains(Value *Expr, Value *V) {
395 auto *C = dyn_cast<Constant>(V);
399 auto *CE = dyn_cast<ConstantExpr>(Expr);
403 SmallPtrSet<ConstantExpr *, 4> Cache;
404 return contains(Cache, CE, C);
408 void Value::doRAUW(Value *New, bool NoMetadata) {
409 assert(New && "Value::replaceAllUsesWith(<null>) is invalid!");
410 assert(!contains(New, this) &&
411 "this->replaceAllUsesWith(expr(this)) is NOT valid!");
412 assert(New->getType() == getType() &&
413 "replaceAllUses of value with new value of different type!");
415 // Notify all ValueHandles (if present) that this value is going away.
417 ValueHandleBase::ValueIsRAUWd(this, New);
418 if (!NoMetadata && isUsedByMetadata())
419 ValueAsMetadata::handleRAUW(this, New);
421 while (!materialized_use_empty()) {
423 // Must handle Constants specially, we cannot call replaceUsesOfWith on a
424 // constant because they are uniqued.
425 if (auto *C = dyn_cast<Constant>(U.getUser())) {
426 if (!isa<GlobalValue>(C)) {
427 C->handleOperandChange(this, New);
435 if (BasicBlock *BB = dyn_cast<BasicBlock>(this))
436 BB->replaceSuccessorsPhiUsesWith(cast<BasicBlock>(New));
439 void Value::replaceAllUsesWith(Value *New) {
440 doRAUW(New, false /* NoMetadata */);
443 void Value::replaceNonMetadataUsesWith(Value *New) {
444 doRAUW(New, true /* NoMetadata */);
447 // Like replaceAllUsesWith except it does not handle constants or basic blocks.
448 // This routine leaves uses within BB.
449 void Value::replaceUsesOutsideBlock(Value *New, BasicBlock *BB) {
450 assert(New && "Value::replaceUsesOutsideBlock(<null>, BB) is invalid!");
451 assert(!contains(New, this) &&
452 "this->replaceUsesOutsideBlock(expr(this), BB) is NOT valid!");
453 assert(New->getType() == getType() &&
454 "replaceUses of value with new value of different type!");
455 assert(BB && "Basic block that may contain a use of 'New' must be defined\n");
457 use_iterator UI = use_begin(), E = use_end();
461 auto *Usr = dyn_cast<Instruction>(U.getUser());
462 if (Usr && Usr->getParent() == BB)
469 // Various metrics for how much to strip off of pointers.
470 enum PointerStripKind {
472 PSK_ZeroIndicesAndAliases,
473 PSK_ZeroIndicesAndAliasesAndInvariantGroups,
474 PSK_InBoundsConstantIndices,
478 template <PointerStripKind StripKind>
479 static const Value *stripPointerCastsAndOffsets(const Value *V) {
480 if (!V->getType()->isPointerTy())
483 // Even though we don't look through PHI nodes, we could be called on an
484 // instruction in an unreachable block, which may be on a cycle.
485 SmallPtrSet<const Value *, 4> Visited;
489 if (auto *GEP = dyn_cast<GEPOperator>(V)) {
491 case PSK_ZeroIndicesAndAliases:
492 case PSK_ZeroIndicesAndAliasesAndInvariantGroups:
493 case PSK_ZeroIndices:
494 if (!GEP->hasAllZeroIndices())
497 case PSK_InBoundsConstantIndices:
498 if (!GEP->hasAllConstantIndices())
502 if (!GEP->isInBounds())
506 V = GEP->getPointerOperand();
507 } else if (Operator::getOpcode(V) == Instruction::BitCast ||
508 Operator::getOpcode(V) == Instruction::AddrSpaceCast) {
509 V = cast<Operator>(V)->getOperand(0);
510 } else if (auto *GA = dyn_cast<GlobalAlias>(V)) {
511 if (StripKind == PSK_ZeroIndices || GA->isInterposable())
513 V = GA->getAliasee();
515 if (auto CS = ImmutableCallSite(V)) {
516 if (const Value *RV = CS.getReturnedArgOperand()) {
520 // The result of launder.invariant.group must alias it's argument,
521 // but it can't be marked with returned attribute, that's why it needs
523 if (StripKind == PSK_ZeroIndicesAndAliasesAndInvariantGroups &&
524 (CS.getIntrinsicID() == Intrinsic::launder_invariant_group ||
525 CS.getIntrinsicID() == Intrinsic::strip_invariant_group)) {
526 V = CS.getArgOperand(0);
532 assert(V->getType()->isPointerTy() && "Unexpected operand type!");
533 } while (Visited.insert(V).second);
537 } // end anonymous namespace
539 const Value *Value::stripPointerCasts() const {
540 return stripPointerCastsAndOffsets<PSK_ZeroIndicesAndAliases>(this);
543 const Value *Value::stripPointerCastsNoFollowAliases() const {
544 return stripPointerCastsAndOffsets<PSK_ZeroIndices>(this);
547 const Value *Value::stripInBoundsConstantOffsets() const {
548 return stripPointerCastsAndOffsets<PSK_InBoundsConstantIndices>(this);
551 const Value *Value::stripPointerCastsAndInvariantGroups() const {
552 return stripPointerCastsAndOffsets<PSK_ZeroIndicesAndAliasesAndInvariantGroups>(
557 Value::stripAndAccumulateInBoundsConstantOffsets(const DataLayout &DL,
558 APInt &Offset) const {
559 if (!getType()->isPointerTy())
562 assert(Offset.getBitWidth() == DL.getIndexSizeInBits(cast<PointerType>(
563 getType())->getAddressSpace()) &&
564 "The offset bit width does not match the DL specification.");
566 // Even though we don't look through PHI nodes, we could be called on an
567 // instruction in an unreachable block, which may be on a cycle.
568 SmallPtrSet<const Value *, 4> Visited;
569 Visited.insert(this);
570 const Value *V = this;
572 if (auto *GEP = dyn_cast<GEPOperator>(V)) {
573 if (!GEP->isInBounds())
575 APInt GEPOffset(Offset);
576 if (!GEP->accumulateConstantOffset(DL, GEPOffset))
579 V = GEP->getPointerOperand();
580 } else if (Operator::getOpcode(V) == Instruction::BitCast) {
581 V = cast<Operator>(V)->getOperand(0);
582 } else if (auto *GA = dyn_cast<GlobalAlias>(V)) {
583 V = GA->getAliasee();
585 if (auto CS = ImmutableCallSite(V))
586 if (const Value *RV = CS.getReturnedArgOperand()) {
593 assert(V->getType()->isPointerTy() && "Unexpected operand type!");
594 } while (Visited.insert(V).second);
599 const Value *Value::stripInBoundsOffsets() const {
600 return stripPointerCastsAndOffsets<PSK_InBounds>(this);
603 uint64_t Value::getPointerDereferenceableBytes(const DataLayout &DL,
604 bool &CanBeNull) const {
605 assert(getType()->isPointerTy() && "must be pointer");
607 uint64_t DerefBytes = 0;
609 if (const Argument *A = dyn_cast<Argument>(this)) {
610 DerefBytes = A->getDereferenceableBytes();
611 if (DerefBytes == 0 && (A->hasByValAttr() || A->hasStructRetAttr())) {
612 Type *PT = cast<PointerType>(A->getType())->getElementType();
614 DerefBytes = DL.getTypeStoreSize(PT);
616 if (DerefBytes == 0) {
617 DerefBytes = A->getDereferenceableOrNullBytes();
620 } else if (auto CS = ImmutableCallSite(this)) {
621 DerefBytes = CS.getDereferenceableBytes(AttributeList::ReturnIndex);
622 if (DerefBytes == 0) {
623 DerefBytes = CS.getDereferenceableOrNullBytes(AttributeList::ReturnIndex);
626 } else if (const LoadInst *LI = dyn_cast<LoadInst>(this)) {
627 if (MDNode *MD = LI->getMetadata(LLVMContext::MD_dereferenceable)) {
628 ConstantInt *CI = mdconst::extract<ConstantInt>(MD->getOperand(0));
629 DerefBytes = CI->getLimitedValue();
631 if (DerefBytes == 0) {
633 LI->getMetadata(LLVMContext::MD_dereferenceable_or_null)) {
634 ConstantInt *CI = mdconst::extract<ConstantInt>(MD->getOperand(0));
635 DerefBytes = CI->getLimitedValue();
639 } else if (auto *AI = dyn_cast<AllocaInst>(this)) {
640 if (!AI->isArrayAllocation()) {
641 DerefBytes = DL.getTypeStoreSize(AI->getAllocatedType());
644 } else if (auto *GV = dyn_cast<GlobalVariable>(this)) {
645 if (GV->getValueType()->isSized() && !GV->hasExternalWeakLinkage()) {
646 // TODO: Don't outright reject hasExternalWeakLinkage but set the
648 DerefBytes = DL.getTypeStoreSize(GV->getValueType());
655 unsigned Value::getPointerAlignment(const DataLayout &DL) const {
656 assert(getType()->isPointerTy() && "must be pointer");
659 if (auto *GO = dyn_cast<GlobalObject>(this)) {
660 // Don't make any assumptions about function pointer alignment. Some
661 // targets use the LSBs to store additional information.
662 if (isa<Function>(GO))
664 Align = GO->getAlignment();
666 if (auto *GVar = dyn_cast<GlobalVariable>(GO)) {
667 Type *ObjectType = GVar->getValueType();
668 if (ObjectType->isSized()) {
669 // If the object is defined in the current Module, we'll be giving
670 // it the preferred alignment. Otherwise, we have to assume that it
671 // may only have the minimum ABI alignment.
672 if (GVar->isStrongDefinitionForLinker())
673 Align = DL.getPreferredAlignment(GVar);
675 Align = DL.getABITypeAlignment(ObjectType);
679 } else if (const Argument *A = dyn_cast<Argument>(this)) {
680 Align = A->getParamAlignment();
682 if (!Align && A->hasStructRetAttr()) {
683 // An sret parameter has at least the ABI alignment of the return type.
684 Type *EltTy = cast<PointerType>(A->getType())->getElementType();
685 if (EltTy->isSized())
686 Align = DL.getABITypeAlignment(EltTy);
688 } else if (const AllocaInst *AI = dyn_cast<AllocaInst>(this)) {
689 Align = AI->getAlignment();
691 Type *AllocatedType = AI->getAllocatedType();
692 if (AllocatedType->isSized())
693 Align = DL.getPrefTypeAlignment(AllocatedType);
695 } else if (auto CS = ImmutableCallSite(this))
696 Align = CS.getAttributes().getRetAlignment();
697 else if (const LoadInst *LI = dyn_cast<LoadInst>(this))
698 if (MDNode *MD = LI->getMetadata(LLVMContext::MD_align)) {
699 ConstantInt *CI = mdconst::extract<ConstantInt>(MD->getOperand(0));
700 Align = CI->getLimitedValue();
706 const Value *Value::DoPHITranslation(const BasicBlock *CurBB,
707 const BasicBlock *PredBB) const {
708 auto *PN = dyn_cast<PHINode>(this);
709 if (PN && PN->getParent() == CurBB)
710 return PN->getIncomingValueForBlock(PredBB);
714 LLVMContext &Value::getContext() const { return VTy->getContext(); }
716 void Value::reverseUseList() {
717 if (!UseList || !UseList->Next)
718 // No need to reverse 0 or 1 uses.
722 Use *Current = UseList->Next;
723 Head->Next = nullptr;
725 Use *Next = Current->Next;
726 Current->Next = Head;
727 Head->setPrev(&Current->Next);
732 Head->setPrev(&UseList);
735 bool Value::isSwiftError() const {
736 auto *Arg = dyn_cast<Argument>(this);
738 return Arg->hasSwiftErrorAttr();
739 auto *Alloca = dyn_cast<AllocaInst>(this);
742 return Alloca->isSwiftError();
745 //===----------------------------------------------------------------------===//
746 // ValueHandleBase Class
747 //===----------------------------------------------------------------------===//
749 void ValueHandleBase::AddToExistingUseList(ValueHandleBase **List) {
750 assert(List && "Handle list is null?");
752 // Splice ourselves into the list.
757 Next->setPrevPtr(&Next);
758 assert(getValPtr() == Next->getValPtr() && "Added to wrong list?");
762 void ValueHandleBase::AddToExistingUseListAfter(ValueHandleBase *List) {
763 assert(List && "Must insert after existing node");
766 setPrevPtr(&List->Next);
769 Next->setPrevPtr(&Next);
772 void ValueHandleBase::AddToUseList() {
773 assert(getValPtr() && "Null pointer doesn't have a use list!");
775 LLVMContextImpl *pImpl = getValPtr()->getContext().pImpl;
777 if (getValPtr()->HasValueHandle) {
778 // If this value already has a ValueHandle, then it must be in the
779 // ValueHandles map already.
780 ValueHandleBase *&Entry = pImpl->ValueHandles[getValPtr()];
781 assert(Entry && "Value doesn't have any handles?");
782 AddToExistingUseList(&Entry);
786 // Ok, it doesn't have any handles yet, so we must insert it into the
787 // DenseMap. However, doing this insertion could cause the DenseMap to
788 // reallocate itself, which would invalidate all of the PrevP pointers that
789 // point into the old table. Handle this by checking for reallocation and
790 // updating the stale pointers only if needed.
791 DenseMap<Value*, ValueHandleBase*> &Handles = pImpl->ValueHandles;
792 const void *OldBucketPtr = Handles.getPointerIntoBucketsArray();
794 ValueHandleBase *&Entry = Handles[getValPtr()];
795 assert(!Entry && "Value really did already have handles?");
796 AddToExistingUseList(&Entry);
797 getValPtr()->HasValueHandle = true;
799 // If reallocation didn't happen or if this was the first insertion, don't
801 if (Handles.isPointerIntoBucketsArray(OldBucketPtr) ||
802 Handles.size() == 1) {
806 // Okay, reallocation did happen. Fix the Prev Pointers.
807 for (DenseMap<Value*, ValueHandleBase*>::iterator I = Handles.begin(),
808 E = Handles.end(); I != E; ++I) {
809 assert(I->second && I->first == I->second->getValPtr() &&
810 "List invariant broken!");
811 I->second->setPrevPtr(&I->second);
815 void ValueHandleBase::RemoveFromUseList() {
816 assert(getValPtr() && getValPtr()->HasValueHandle &&
817 "Pointer doesn't have a use list!");
819 // Unlink this from its use list.
820 ValueHandleBase **PrevPtr = getPrevPtr();
821 assert(*PrevPtr == this && "List invariant broken");
825 assert(Next->getPrevPtr() == &Next && "List invariant broken");
826 Next->setPrevPtr(PrevPtr);
830 // If the Next pointer was null, then it is possible that this was the last
831 // ValueHandle watching VP. If so, delete its entry from the ValueHandles
833 LLVMContextImpl *pImpl = getValPtr()->getContext().pImpl;
834 DenseMap<Value*, ValueHandleBase*> &Handles = pImpl->ValueHandles;
835 if (Handles.isPointerIntoBucketsArray(PrevPtr)) {
836 Handles.erase(getValPtr());
837 getValPtr()->HasValueHandle = false;
841 void ValueHandleBase::ValueIsDeleted(Value *V) {
842 assert(V->HasValueHandle && "Should only be called if ValueHandles present");
844 // Get the linked list base, which is guaranteed to exist since the
845 // HasValueHandle flag is set.
846 LLVMContextImpl *pImpl = V->getContext().pImpl;
847 ValueHandleBase *Entry = pImpl->ValueHandles[V];
848 assert(Entry && "Value bit set but no entries exist");
850 // We use a local ValueHandleBase as an iterator so that ValueHandles can add
851 // and remove themselves from the list without breaking our iteration. This
852 // is not really an AssertingVH; we just have to give ValueHandleBase a kind.
853 // Note that we deliberately do not the support the case when dropping a value
854 // handle results in a new value handle being permanently added to the list
855 // (as might occur in theory for CallbackVH's): the new value handle will not
856 // be processed and the checking code will mete out righteous punishment if
857 // the handle is still present once we have finished processing all the other
858 // value handles (it is fine to momentarily add then remove a value handle).
859 for (ValueHandleBase Iterator(Assert, *Entry); Entry; Entry = Iterator.Next) {
860 Iterator.RemoveFromUseList();
861 Iterator.AddToExistingUseListAfter(Entry);
862 assert(Entry->Next == &Iterator && "Loop invariant broken.");
864 switch (Entry->getKind()) {
869 // WeakTracking and Weak just go to null, which unlinks them
871 Entry->operator=(nullptr);
874 // Forward to the subclass's implementation.
875 static_cast<CallbackVH*>(Entry)->deleted();
880 // All callbacks, weak references, and assertingVHs should be dropped by now.
881 if (V->HasValueHandle) {
882 #ifndef NDEBUG // Only in +Asserts mode...
883 dbgs() << "While deleting: " << *V->getType() << " %" << V->getName()
885 if (pImpl->ValueHandles[V]->getKind() == Assert)
886 llvm_unreachable("An asserting value handle still pointed to this"
890 llvm_unreachable("All references to V were not removed?");
894 void ValueHandleBase::ValueIsRAUWd(Value *Old, Value *New) {
895 assert(Old->HasValueHandle &&"Should only be called if ValueHandles present");
896 assert(Old != New && "Changing value into itself!");
897 assert(Old->getType() == New->getType() &&
898 "replaceAllUses of value with new value of different type!");
900 // Get the linked list base, which is guaranteed to exist since the
901 // HasValueHandle flag is set.
902 LLVMContextImpl *pImpl = Old->getContext().pImpl;
903 ValueHandleBase *Entry = pImpl->ValueHandles[Old];
905 assert(Entry && "Value bit set but no entries exist");
907 // We use a local ValueHandleBase as an iterator so that
908 // ValueHandles can add and remove themselves from the list without
909 // breaking our iteration. This is not really an AssertingVH; we
910 // just have to give ValueHandleBase some kind.
911 for (ValueHandleBase Iterator(Assert, *Entry); Entry; Entry = Iterator.Next) {
912 Iterator.RemoveFromUseList();
913 Iterator.AddToExistingUseListAfter(Entry);
914 assert(Entry->Next == &Iterator && "Loop invariant broken.");
916 switch (Entry->getKind()) {
919 // Asserting and Weak handles do not follow RAUW implicitly.
922 // Weak goes to the new value, which will unlink it from Old's list.
923 Entry->operator=(New);
926 // Forward to the subclass's implementation.
927 static_cast<CallbackVH*>(Entry)->allUsesReplacedWith(New);
933 // If any new weak value handles were added while processing the
934 // list, then complain about it now.
935 if (Old->HasValueHandle)
936 for (Entry = pImpl->ValueHandles[Old]; Entry; Entry = Entry->Next)
937 switch (Entry->getKind()) {
939 dbgs() << "After RAUW from " << *Old->getType() << " %"
940 << Old->getName() << " to " << *New->getType() << " %"
941 << New->getName() << "\n";
943 "A weak tracking value handle still pointed to the old value!\n");
950 // Pin the vtable to this file.
951 void CallbackVH::anchor() {}