X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FVMCore%2FValue.cpp;h=c952b7888cddcf3a3dce97c14ac5846887dcf32b;hb=7ce720b448c581b822577aaf44b73a5aa9689dfc;hp=402171be36ab10a421c801f018ef7e14b492a955;hpb=d1e693f2a3883dacf213aa2b477540c57b53b714;p=oota-llvm.git diff --git a/lib/VMCore/Value.cpp b/lib/VMCore/Value.cpp index 402171be36a..c952b7888cd 100644 --- a/lib/VMCore/Value.cpp +++ b/lib/VMCore/Value.cpp @@ -1,14 +1,32 @@ //===-- Value.cpp - Implement the Value class -----------------------------===// // -// This file implements the Value and User classes. +// 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 Value, ValueHandle, and User classes. // //===----------------------------------------------------------------------===// -#include "llvm/InstrTypes.h" -#include "llvm/SymbolTable.h" +#include "llvm/Constant.h" +#include "llvm/Constants.h" #include "llvm/DerivedTypes.h" -#include "Support/LeakDetector.h" +#include "llvm/InstrTypes.h" +#include "llvm/Instructions.h" +#include "llvm/Module.h" +#include "llvm/ValueSymbolTable.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/LeakDetector.h" +#include "llvm/Support/ManagedStatic.h" +#include "llvm/Support/ValueHandle.h" +#include "llvm/System/RWMutex.h" +#include "llvm/System/Threading.h" +#include "llvm/ADT/DenseMap.h" #include +using namespace llvm; //===----------------------------------------------------------------------===// // Value Class @@ -19,93 +37,551 @@ static inline const Type *checkType(const Type *Ty) { return Ty; } -Value::Value(const Type *ty, ValueTy vty, const std::string &name) - : Name(name), Ty(checkType(ty), this) { - VTy = vty; +Value::Value(const Type *ty, unsigned scid) + : SubclassID(scid), HasValueHandle(0), SubclassData(0), VTy(checkType(ty)), + UseList(0), Name(0) { + if (isa(this) || isa(this)) + assert((VTy->isFirstClassType() || VTy == Type::VoidTy || + isa(ty) || VTy->getTypeID() == Type::StructTyID) && + "invalid CallInst type!"); + else if (!isa(this) && !isa(this)) + assert((VTy->isFirstClassType() || VTy == Type::VoidTy || + isa(ty)) && + "Cannot create non-first-class values except for constants!"); } Value::~Value() { + // Notify all ValueHandles (if present) that this value is going away. + if (HasValueHandle) + ValueHandleBase::ValueIsDeleted(this); + #ifndef NDEBUG // Only in -g mode... // Check to make sure that there are no uses of this value that are still // around when the value is destroyed. If there are, then we have a dangling // reference and something is wrong. This code is here to print out what is - // still being referenced. The value in question should be printed as + // still being referenced. The value in question should be printed as // a // - if (Uses.begin() != Uses.end()) { - std::cerr << "While deleting: " << Ty << "%" << Name << "\n"; - for (use_const_iterator I = Uses.begin(); I != Uses.end(); ++I) - std::cerr << "Use still stuck around after Def is destroyed:" - << **I << "\n"; + if (!use_empty()) { + cerr << "While deleting: " << *VTy << " %" << getNameStr() << "\n"; + for (use_iterator I = use_begin(), E = use_end(); I != E; ++I) + cerr << "Use still stuck around after Def is destroyed:" + << **I << "\n"; } #endif - assert(Uses.begin() == Uses.end()); + assert(use_empty() && "Uses remain when a value is destroyed!"); + // If this value is named, destroy the name. This should not be in a symtab + // at this point. + if (Name) + Name->Destroy(); + // There should be no uses of this object anymore, remove it. LeakDetector::removeGarbageObject(this); } -void Value::replaceAllUsesWith(Value *D) { - assert(D && "Value::replaceAllUsesWith() is invalid!"); - assert(D != this && "V->replaceAllUsesWith(V) is NOT valid!"); - assert(D->getType() == getType() && - "replaceAllUses of value with new value of different type!"); - while (!Uses.empty()) { - User *Use = Uses.back(); -#ifndef NDEBUG - unsigned NumUses = Uses.size(); -#endif - Use->replaceUsesOfWith(this, D); +/// hasNUses - Return true if this Value has exactly N users. +/// +bool Value::hasNUses(unsigned N) const { + use_const_iterator UI = use_begin(), E = use_end(); -#ifndef NDEBUG // only in -g mode... - if (Uses.size() == NumUses) - std::cerr << "Use: " << *Use << "replace with: " << *D; -#endif - assert(Uses.size() != NumUses && "Didn't remove definition!"); + for (; N; --N, ++UI) + if (UI == E) return false; // Too few. + return UI == E; +} + +/// hasNUsesOrMore - Return true if this value has N users or more. This is +/// logically equivalent to getNumUses() >= N. +/// +bool Value::hasNUsesOrMore(unsigned N) const { + use_const_iterator UI = use_begin(), E = use_end(); + + for (; N; --N, ++UI) + if (UI == E) return false; // Too few. + + return true; +} + +/// isUsedInBasicBlock - Return true if this value is used in the specified +/// basic block. +bool Value::isUsedInBasicBlock(const BasicBlock *BB) const { + for (use_const_iterator I = use_begin(), E = use_end(); I != E; ++I) { + const Instruction *User = dyn_cast(*I); + if (User && User->getParent() == BB) + return true; + } + return false; +} + + +/// getNumUses - This method computes the number of uses of this Value. This +/// is a linear time operation. Use hasOneUse or hasNUses to check for specific +/// values. +unsigned Value::getNumUses() const { + return (unsigned)std::distance(use_begin(), use_end()); +} + +static bool getSymTab(Value *V, ValueSymbolTable *&ST) { + ST = 0; + if (Instruction *I = dyn_cast(V)) { + if (BasicBlock *P = I->getParent()) + if (Function *PP = P->getParent()) + ST = &PP->getValueSymbolTable(); + } else if (BasicBlock *BB = dyn_cast(V)) { + if (Function *P = BB->getParent()) + ST = &P->getValueSymbolTable(); + } else if (GlobalValue *GV = dyn_cast(V)) { + if (Module *P = GV->getParent()) + ST = &P->getValueSymbolTable(); + } else if (Argument *A = dyn_cast(V)) { + if (Function *P = A->getParent()) + ST = &P->getValueSymbolTable(); + } else { + assert(isa(V) && "Unknown value type!"); + return true; // no name is setable for this. + } + return false; +} + +/// getNameStart - Return a pointer to a null terminated string for this name. +/// Note that names can have null characters within the string as well as at +/// their end. This always returns a non-null pointer. +const char *Value::getNameStart() const { + if (Name == 0) return ""; + return Name->getKeyData(); +} + +/// getNameLen - Return the length of the string, correctly handling nul +/// characters embedded into them. +unsigned Value::getNameLen() const { + return Name ? Name->getKeyLength() : 0; +} + +/// isName - Return true if this value has the name specified by the provided +/// nul terminated string. +bool Value::isName(const char *N) const { + unsigned InLen = strlen(N); + return InLen == getNameLen() && memcmp(getNameStart(), N, InLen) == 0; +} + + +std::string Value::getNameStr() const { + if (Name == 0) return ""; + return std::string(Name->getKeyData(), + Name->getKeyData()+Name->getKeyLength()); +} + +void Value::setName(const std::string &name) { + setName(&name[0], name.size()); +} + +void Value::setName(const char *Name) { + setName(Name, Name ? strlen(Name) : 0); +} + +void Value::setName(const char *NameStr, unsigned NameLen) { + if (NameLen == 0 && !hasName()) return; + assert(getType() != Type::VoidTy && "Cannot assign a name to void values!"); + + // Get the symbol table to update for this object. + ValueSymbolTable *ST; + if (getSymTab(this, ST)) + return; // Cannot set a name on this value (e.g. constant). + + if (!ST) { // No symbol table to update? Just do the change. + if (NameLen == 0) { + // Free the name for this value. + Name->Destroy(); + Name = 0; + return; + } + + if (Name) { + // Name isn't changing? + if (NameLen == Name->getKeyLength() && + !memcmp(Name->getKeyData(), NameStr, NameLen)) + return; + Name->Destroy(); + } + + // NOTE: Could optimize for the case the name is shrinking to not deallocate + // then reallocated. + + // Create the new name. + Name = ValueName::Create(NameStr, NameStr+NameLen); + Name->setValue(this); + return; + } + + // NOTE: Could optimize for the case the name is shrinking to not deallocate + // then reallocated. + if (hasName()) { + // Name isn't changing? + if (NameLen == Name->getKeyLength() && + !memcmp(Name->getKeyData(), NameStr, NameLen)) + return; + + // Remove old name. + ST->removeValueName(Name); + Name->Destroy(); + Name = 0; + + if (NameLen == 0) + return; } + + // Name is changing to something new. + Name = ST->createValueName(NameStr, NameLen, this); } -// refineAbstractType - This function is implemented because we use -// potentially abstract types, and these types may be resolved to more -// concrete types after we are constructed. For the value class, we simply -// change Ty to point to the right type. :) + +/// takeName - transfer the name from V to this value, setting V's name to +/// empty. It is an error to call V->takeName(V). +void Value::takeName(Value *V) { + ValueSymbolTable *ST = 0; + // If this value has a name, drop it. + if (hasName()) { + // Get the symtab this is in. + if (getSymTab(this, ST)) { + // We can't set a name on this value, but we need to clear V's name if + // it has one. + if (V->hasName()) V->setName(0, 0); + return; // Cannot set a name on this value (e.g. constant). + } + + // Remove old name. + if (ST) + ST->removeValueName(Name); + Name->Destroy(); + Name = 0; + } + + // Now we know that this has no name. + + // If V has no name either, we're done. + if (!V->hasName()) return; + + // Get this's symtab if we didn't before. + if (!ST) { + if (getSymTab(this, ST)) { + // Clear V's name. + V->setName(0, 0); + return; // Cannot set a name on this value (e.g. constant). + } + } + + // Get V's ST, this should always succed, because V has a name. + ValueSymbolTable *VST; + bool Failure = getSymTab(V, VST); + assert(!Failure && "V has a name, so it should have a ST!"); Failure=Failure; + + // If these values are both in the same symtab, we can do this very fast. + // This works even if both values have no symtab yet. + if (ST == VST) { + // Take the name! + Name = V->Name; + V->Name = 0; + Name->setValue(this); + return; + } + + // Otherwise, things are slightly more complex. Remove V's name from VST and + // then reinsert it into ST. + + if (VST) + VST->removeValueName(V->Name); + Name = V->Name; + V->Name = 0; + Name->setValue(this); + + if (ST) + ST->reinsertValue(this); +} + + +// uncheckedReplaceAllUsesWith - This is exactly the same as replaceAllUsesWith, +// except that it doesn't have all of the asserts. The asserts fail because we +// are half-way done resolving types, which causes some types to exist as two +// different Type*'s at the same time. This is a sledgehammer to work around +// this problem. // -void Value::refineAbstractType(const DerivedType *OldTy, const Type *NewTy) { - assert(Ty.get() == OldTy && "Can't refine anything but my type!"); - if (OldTy == NewTy && !OldTy->isAbstract()) - Ty.removeUserFromConcrete(); - Ty = NewTy; +void Value::uncheckedReplaceAllUsesWith(Value *New) { + // Notify all ValueHandles (if present) that this value is going away. + if (HasValueHandle) + ValueHandleBase::ValueIsRAUWd(this, New); + + while (!use_empty()) { + Use &U = *UseList; + // Must handle Constants specially, we cannot call replaceUsesOfWith on a + // constant because they are uniqued. + if (Constant *C = dyn_cast(U.getUser())) { + if (!isa(C)) { + C->replaceUsesOfWithOnConstant(this, New, &U); + continue; + } + } + + U.set(New); + } } -void Value::killUse(User *i) { - if (i == 0) return; - use_iterator I = find(Uses.begin(), Uses.end(), i); +void Value::replaceAllUsesWith(Value *New) { + assert(New && "Value::replaceAllUsesWith() is invalid!"); + assert(New != this && "this->replaceAllUsesWith(this) is NOT valid!"); + assert(New->getType() == getType() && + "replaceAllUses of value with new value of different type!"); + + uncheckedReplaceAllUsesWith(New); +} + +Value *Value::stripPointerCasts() { + if (!isa(getType())) + return this; + Value *V = this; + do { + if (ConstantExpr *CE = dyn_cast(V)) { + if (CE->getOpcode() == Instruction::GetElementPtr) { + for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i) + if (!CE->getOperand(i)->isNullValue()) + return V; + V = CE->getOperand(0); + } else if (CE->getOpcode() == Instruction::BitCast) { + V = CE->getOperand(0); + } else { + return V; + } + } else if (GetElementPtrInst *GEP = dyn_cast(V)) { + if (!GEP->hasAllZeroIndices()) + return V; + V = GEP->getOperand(0); + } else if (BitCastInst *CI = dyn_cast(V)) { + V = CI->getOperand(0); + } else { + return V; + } + assert(isa(V->getType()) && "Unexpected operand type!"); + } while (1); +} - assert(I != Uses.end() && "Use not in uses list!!"); - Uses.erase(I); +Value *Value::getUnderlyingObject() { + if (!isa(getType())) + return this; + Value *V = this; + unsigned MaxLookup = 6; + do { + if (Instruction *I = dyn_cast(V)) { + if (!isa(I) && !isa(I)) + return V; + V = I->getOperand(0); + } else if (ConstantExpr *CE = dyn_cast(V)) { + if (CE->getOpcode() != Instruction::BitCast && + CE->getOpcode() != Instruction::GetElementPtr) + return V; + V = CE->getOperand(0); + } else { + return V; + } + assert(isa(V->getType()) && "Unexpected operand type!"); + } while (--MaxLookup); + return V; } -User *Value::use_remove(use_iterator &I) { - assert(I != Uses.end() && "Trying to remove the end of the use list!!!"); - User *i = *I; - I = Uses.erase(I); - return i; +/// DoPHITranslation - If this value is a PHI node with CurBB as its parent, +/// return the value in the PHI node corresponding to PredBB. If not, return +/// ourself. This is useful if you want to know the value something has in a +/// predecessor block. +Value *Value::DoPHITranslation(const BasicBlock *CurBB, + const BasicBlock *PredBB) { + PHINode *PN = dyn_cast(this); + if (PN && PN->getParent() == CurBB) + return PN->getIncomingValueForBlock(PredBB); + return this; } //===----------------------------------------------------------------------===// -// User Class +// ValueHandleBase Class //===----------------------------------------------------------------------===// -User::User(const Type *Ty, ValueTy vty, const std::string &name) - : Value(Ty, vty, name) { +/// ValueHandles - This map keeps track of all of the value handles that are +/// watching a Value*. The Value::HasValueHandle bit is used to know whether or +/// not a value has an entry in this map. +typedef DenseMap ValueHandlesTy; +static ManagedStatic ValueHandles; +static ManagedStatic > ValueHandlesLock; + +/// AddToExistingUseList - Add this ValueHandle to the use list for VP, where +/// List is known to point into the existing use list. +void ValueHandleBase::AddToExistingUseList(ValueHandleBase **List) { + assert(List && "Handle list is null?"); + + // Splice ourselves into the list. + Next = *List; + *List = this; + setPrevPtr(List); + if (Next) { + Next->setPrevPtr(&Next); + assert(VP == Next->VP && "Added to wrong list?"); + } +} + +/// AddToUseList - Add this ValueHandle to the use list for VP. +void ValueHandleBase::AddToUseList() { + assert(VP && "Null pointer doesn't have a use list!"); + if (VP->HasValueHandle) { + // If this value already has a ValueHandle, then it must be in the + // ValueHandles map already. + sys::SmartScopedReader Reader(&*ValueHandlesLock); + ValueHandleBase *&Entry = (*ValueHandles)[VP]; + assert(Entry != 0 && "Value doesn't have any handles?"); + AddToExistingUseList(&Entry); + return; + } + + // Ok, it doesn't have any handles yet, so we must insert it into the + // DenseMap. However, doing this insertion could cause the DenseMap to + // reallocate itself, which would invalidate all of the PrevP pointers that + // point into the old table. Handle this by checking for reallocation and + // updating the stale pointers only if needed. + sys::SmartScopedWriter Writer(&*ValueHandlesLock); + ValueHandlesTy &Handles = *ValueHandles; + const void *OldBucketPtr = Handles.getPointerIntoBucketsArray(); + + ValueHandleBase *&Entry = Handles[VP]; + assert(Entry == 0 && "Value really did already have handles?"); + AddToExistingUseList(&Entry); + VP->HasValueHandle = true; + + // If reallocation didn't happen or if this was the first insertion, don't + // walk the table. + if (Handles.isPointerIntoBucketsArray(OldBucketPtr) || + Handles.size() == 1) { + return; + } + + // Okay, reallocation did happen. Fix the Prev Pointers. + for (ValueHandlesTy::iterator I = Handles.begin(), E = Handles.end(); + I != E; ++I) { + assert(I->second && I->first == I->second->VP && "List invariant broken!"); + I->second->setPrevPtr(&I->second); + } } +/// RemoveFromUseList - Remove this ValueHandle from its current use list. +void ValueHandleBase::RemoveFromUseList() { + assert(VP && VP->HasValueHandle && "Pointer doesn't have a use list!"); + + // Unlink this from its use list. + ValueHandleBase **PrevPtr = getPrevPtr(); + assert(*PrevPtr == this && "List invariant broken"); + + *PrevPtr = Next; + if (Next) { + assert(Next->getPrevPtr() == &Next && "List invariant broken"); + Next->setPrevPtr(PrevPtr); + return; + } + + // If the Next pointer was null, then it is possible that this was the last + // ValueHandle watching VP. If so, delete its entry from the ValueHandles + // map. + sys::SmartScopedWriter Writer(&*ValueHandlesLock); + ValueHandlesTy &Handles = *ValueHandles; + if (Handles.isPointerIntoBucketsArray(PrevPtr)) { + Handles.erase(VP); + VP->HasValueHandle = false; + } +} + + +void ValueHandleBase::ValueIsDeleted(Value *V) { + assert(V->HasValueHandle && "Should only be called if ValueHandles present"); + + // Get the linked list base, which is guaranteed to exist since the + // HasValueHandle flag is set. + ValueHandlesLock->reader_acquire(); + ValueHandleBase *Entry = (*ValueHandles)[V]; + ValueHandlesLock->reader_release(); + assert(Entry && "Value bit set but no entries exist"); + + while (Entry) { + // Advance pointer to avoid invalidation. + ValueHandleBase *ThisNode = Entry; + Entry = Entry->Next; + + switch (ThisNode->getKind()) { + case Assert: +#ifndef NDEBUG // Only in -g mode... + cerr << "While deleting: " << *V->getType() << " %" << V->getNameStr() + << "\n"; +#endif + cerr << "An asserting value handle still pointed to this value!\n"; + abort(); + case Weak: + // Weak just goes to null, which will unlink it from the list. + ThisNode->operator=(0); + break; + case Callback: + // Forward to the subclass's implementation. + static_cast(ThisNode)->deleted(); + break; + } + } + + // All callbacks and weak references should be dropped by now. + assert(!V->HasValueHandle && "All references to V were not removed?"); +} + + +void ValueHandleBase::ValueIsRAUWd(Value *Old, Value *New) { + assert(Old->HasValueHandle &&"Should only be called if ValueHandles present"); + assert(Old != New && "Changing value into itself!"); + + // Get the linked list base, which is guaranteed to exist since the + // HasValueHandle flag is set. + ValueHandlesLock->reader_acquire(); + ValueHandleBase *Entry = (*ValueHandles)[Old]; + ValueHandlesLock->reader_release(); + assert(Entry && "Value bit set but no entries exist"); + + while (Entry) { + // Advance pointer to avoid invalidation. + ValueHandleBase *ThisNode = Entry; + Entry = Entry->Next; + + switch (ThisNode->getKind()) { + case Assert: + // Asserting handle does not follow RAUW implicitly. + break; + case Weak: + // Weak goes to the new value, which will unlink it from Old's list. + ThisNode->operator=(New); + break; + case Callback: + // Forward to the subclass's implementation. + static_cast(ThisNode)->allUsesReplacedWith(New); + break; + } + } +} + +/// ~CallbackVH. Empty, but defined here to avoid emitting the vtable +/// more than once. +CallbackVH::~CallbackVH() {} + + +//===----------------------------------------------------------------------===// +// User Class +//===----------------------------------------------------------------------===// + // replaceUsesOfWith - Replaces all references to the "From" definition with // references to the "To" definition. // void User::replaceUsesOfWith(Value *From, Value *To) { if (From == To) return; // Duh what? + assert((!isa(this) || isa(this)) && + "Cannot call User::replaceUsesofWith on a constant!"); + for (unsigned i = 0, E = getNumOperands(); i != E; ++i) if (getOperand(i) == From) { // Is This operand is pointing to oldval? // The side effects of this setOperand call include linking to @@ -115,4 +591,3 @@ void User::replaceUsesOfWith(Value *From, Value *To) { } } -