| //===-- Value.cpp - Implement the Value class -----------------------------===// |
| // |
| // 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 and User classes. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Constant.h" |
| #include "llvm/Constants.h" |
| #include "llvm/DerivedTypes.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 <algorithm> |
| using namespace llvm; |
| |
| //===----------------------------------------------------------------------===// |
| // Value Class |
| //===----------------------------------------------------------------------===// |
| |
| static inline const Type *checkType(const Type *Ty) { |
| assert(Ty && "Value defined with a null type: Error!"); |
| return Ty; |
| } |
| |
| Value::Value(const Type *ty, unsigned scid) |
| : SubclassID(scid), SubclassData(0), VTy(checkType(ty)), |
| UseList(0), Name(0) { |
| if (isa<CallInst>(this) || isa<InvokeInst>(this)) |
| assert((VTy->isFirstClassType() || VTy == Type::VoidTy || |
| isa<OpaqueType>(ty) || VTy->getTypeID() == Type::StructTyID) && |
| "invalid CallInst type!"); |
| else if (!isa<Constant>(this) && !isa<BasicBlock>(this)) |
| assert((VTy->isFirstClassType() || VTy == Type::VoidTy || |
| isa<OpaqueType>(ty)) && |
| "Cannot create non-first-class values except for constants!"); |
| } |
| |
| Value::~Value() { |
| #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 |
| // a <badref> |
| // |
| if (!use_empty()) { |
| DOUT << "While deleting: " << *VTy << " %" << getNameStr() << "\n"; |
| for (use_iterator I = use_begin(), E = use_end(); I != E; ++I) |
| DOUT << "Use still stuck around after Def is destroyed:" |
| << **I << "\n"; |
| } |
| #endif |
| 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); |
| } |
| |
| /// 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(); |
| |
| 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<Instruction>(*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<Instruction>(V)) { |
| if (BasicBlock *P = I->getParent()) |
| if (Function *PP = P->getParent()) |
| ST = &PP->getValueSymbolTable(); |
| } else if (BasicBlock *BB = dyn_cast<BasicBlock>(V)) { |
| if (Function *P = BB->getParent()) |
| ST = &P->getValueSymbolTable(); |
| } else if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) { |
| if (Module *P = GV->getParent()) |
| ST = &P->getValueSymbolTable(); |
| } else if (Argument *A = dyn_cast<Argument>(V)) { |
| if (Function *P = A->getParent()) |
| ST = &P->getValueSymbolTable(); |
| } else { |
| assert(isa<Constant>(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); |
| } |
| |
| |
| /// 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::uncheckedReplaceAllUsesWith(Value *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<Constant>(U.getUser())) { |
| if (!isa<GlobalValue>(C)) { |
| C->replaceUsesOfWithOnConstant(this, New, &U); |
| continue; |
| } |
| } |
| |
| U.set(New); |
| } |
| } |
| |
| void Value::replaceAllUsesWith(Value *New) { |
| assert(New && "Value::replaceAllUsesWith(<null>) 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<PointerType>(getType())) |
| return this; |
| |
| if (ConstantExpr *CE = dyn_cast<ConstantExpr>(this)) { |
| if (CE->getOpcode() == Instruction::BitCast) { |
| return CE->getOperand(0)->stripPointerCasts(); |
| } else if (CE->getOpcode() == Instruction::GetElementPtr) { |
| for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i) |
| if (!CE->getOperand(i)->isNullValue()) |
| return this; |
| return CE->getOperand(0)->stripPointerCasts(); |
| } |
| } else if (BitCastInst *CI = dyn_cast<BitCastInst>(this)) { |
| return CI->getOperand(0)->stripPointerCasts(); |
| } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(this)) { |
| if (GEP->hasAllZeroIndices()) |
| return GEP->getOperand(0)->stripPointerCasts(); |
| } |
| return this; |
| } |
| |
| Value *Value::getUnderlyingObject() { |
| if (!isa<PointerType>(getType())) |
| return this; |
| |
| if (Instruction *I = dyn_cast<Instruction>(this)) { |
| if (isa<BitCastInst>(I) || isa<GetElementPtrInst>(I)) |
| return I->getOperand(0)->getUnderlyingObject(); |
| } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(this)) { |
| if (CE->getOpcode() == Instruction::BitCast || |
| CE->getOpcode() == Instruction::GetElementPtr) |
| return CE->getOperand(0)->getUnderlyingObject(); |
| } |
| return this; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // 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<Constant>(this) || isa<GlobalValue>(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 |
| // "To", adding "this" to the uses list of To, and |
| // most importantly, removing "this" from the use list of "From". |
| setOperand(i, To); // Fix it now... |
| } |
| } |
| |
| void *User::operator new(size_t s, unsigned Us) { |
| void *Storage = ::operator new(s + sizeof(Use) * Us); |
| Use *Start = static_cast<Use*>(Storage); |
| Use *End = Start + Us; |
| User *Obj = reinterpret_cast<User*>(End); |
| Obj->OperandList = Start; |
| Obj->NumOperands = Us; |
| Use::initTags(Start, End); |
| return Obj; |
| } |
| |
| void User::operator delete(void *Usr) { |
| User *Start = static_cast<User*>(Usr); |
| Use *Storage = static_cast<Use*>(Usr) - Start->NumOperands; |
| ::operator delete(Storage == Start->OperandList |
| ? Storage |
| : Usr); |
| } |