| //===-- llvm/Value.h - Definition of the Value class ------------*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file declares the Value class. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_VALUE_H |
| #define LLVM_VALUE_H |
| |
| #include "llvm/AbstractTypeUser.h" |
| #include "llvm/Use.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/ADT/Twine.h" |
| #include "llvm/Support/Casting.h" |
| #include <string> |
| |
| namespace llvm { |
| |
| class Constant; |
| class Argument; |
| class Instruction; |
| class BasicBlock; |
| class GlobalValue; |
| class Function; |
| class GlobalVariable; |
| class GlobalAlias; |
| class InlineAsm; |
| class ValueSymbolTable; |
| class TypeSymbolTable; |
| template<typename ValueTy> class StringMapEntry; |
| template <typename ValueTy = Value> |
| class AssertingVH; |
| typedef StringMapEntry<Value*> ValueName; |
| class raw_ostream; |
| class AssemblyAnnotationWriter; |
| class ValueHandleBase; |
| class LLVMContext; |
| |
| //===----------------------------------------------------------------------===// |
| // Value Class |
| //===----------------------------------------------------------------------===// |
| |
| /// This is a very important LLVM class. It is the base class of all values |
| /// computed by a program that may be used as operands to other values. Value is |
| /// the super class of other important classes such as Instruction and Function. |
| /// All Values have a Type. Type is not a subclass of Value. All types can have |
| /// a name and they should belong to some Module. Setting the name on the Value |
| /// automatically updates the module's symbol table. |
| /// |
| /// Every value has a "use list" that keeps track of which other Values are |
| /// using this Value. A Value can also have an arbitrary number of ValueHandle |
| /// objects that watch it and listen to RAUW and Destroy events see |
| /// llvm/Support/ValueHandle.h for details. |
| /// |
| /// @brief LLVM Value Representation |
| class Value { |
| const unsigned char SubclassID; // Subclass identifier (for isa/dyn_cast) |
| unsigned char HasValueHandle : 1; // Has a ValueHandle pointing to this? |
| protected: |
| /// SubclassOptionalData - This member is similar to SubclassData, however it |
| /// is for holding information which may be used to aid optimization, but |
| /// which may be cleared to zero without affecting conservative |
| /// interpretation. |
| unsigned char SubclassOptionalData : 7; |
| |
| /// SubclassData - This member is defined by this class, but is not used for |
| /// anything. Subclasses can use it to hold whatever state they find useful. |
| /// This field is initialized to zero by the ctor. |
| unsigned short SubclassData; |
| private: |
| PATypeHolder VTy; |
| Use *UseList; |
| |
| friend class ValueSymbolTable; // Allow ValueSymbolTable to directly mod Name. |
| friend class SymbolTable; // Allow SymbolTable to directly poke Name. |
| friend class ValueHandleBase; |
| ValueName *Name; |
| |
| void operator=(const Value &); // Do not implement |
| Value(const Value &); // Do not implement |
| |
| public: |
| Value(const Type *Ty, unsigned scid); |
| virtual ~Value(); |
| |
| /// dump - Support for debugging, callable in GDB: V->dump() |
| // |
| virtual void dump() const; |
| |
| /// print - Implement operator<< on Value. |
| /// |
| void print(raw_ostream &O, AssemblyAnnotationWriter *AAW = 0) const; |
| |
| /// All values are typed, get the type of this value. |
| /// |
| inline const Type *getType() const { return VTy; } |
| |
| /// All values hold a context through their type. |
| LLVMContext &getContext() const; |
| |
| // All values can potentially be named... |
| inline bool hasName() const { return Name != 0; } |
| ValueName *getValueName() const { return Name; } |
| |
| /// getName() - Return a constant reference to the value's name. This is cheap |
| /// and guaranteed to return the same reference as long as the value is not |
| /// modified. |
| /// |
| /// This is currently guaranteed to return a StringRef for which data() points |
| /// to a valid null terminated string. The use of StringRef.data() is |
| /// deprecated here, however, and clients should not rely on it. If such |
| /// behavior is needed, clients should use expensive getNameStr(), or switch |
| /// to an interface that does not depend on null termination. |
| StringRef getName() const; |
| |
| /// getNameStr() - Return the name of the specified value, *constructing a |
| /// string* to hold it. This is guaranteed to construct a string and is very |
| /// expensive, clients should use getName() unless necessary. |
| std::string getNameStr() const; |
| |
| /// setName() - Change the name of the value, choosing a new unique name if |
| /// the provided name is taken. |
| /// |
| /// \arg Name - The new name; or "" if the value's name should be removed. |
| void setName(const Twine &Name); |
| |
| |
| /// 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 takeName(Value *V); |
| |
| /// replaceAllUsesWith - Go through the uses list for this definition and make |
| /// each use point to "V" instead of "this". After this completes, 'this's |
| /// use list is guaranteed to be empty. |
| /// |
| void replaceAllUsesWith(Value *V); |
| |
| // uncheckedReplaceAllUsesWith - Just like replaceAllUsesWith but dangerous. |
| // Only use when in type resolution situations! |
| void uncheckedReplaceAllUsesWith(Value *V); |
| |
| /// clearOptionalData - Clear any optional optimization data from this Value. |
| /// Transformation passes must call this method whenever changing the IR |
| /// in a way that would affect the values produced by this Value, unless |
| /// it takes special care to ensure correctness in some other way. |
| void clearOptionalData() { SubclassOptionalData = 0; } |
| |
| //---------------------------------------------------------------------- |
| // Methods for handling the chain of uses of this Value. |
| // |
| typedef value_use_iterator<User> use_iterator; |
| typedef value_use_iterator<const User> use_const_iterator; |
| |
| bool use_empty() const { return UseList == 0; } |
| use_iterator use_begin() { return use_iterator(UseList); } |
| use_const_iterator use_begin() const { return use_const_iterator(UseList); } |
| use_iterator use_end() { return use_iterator(0); } |
| use_const_iterator use_end() const { return use_const_iterator(0); } |
| User *use_back() { return *use_begin(); } |
| const User *use_back() const { return *use_begin(); } |
| |
| /// hasOneUse - Return true if there is exactly one user of this value. This |
| /// is specialized because it is a common request and does not require |
| /// traversing the whole use list. |
| /// |
| bool hasOneUse() const { |
| use_const_iterator I = use_begin(), E = use_end(); |
| if (I == E) return false; |
| return ++I == E; |
| } |
| |
| /// hasNUses - Return true if this Value has exactly N users. |
| /// |
| bool hasNUses(unsigned N) const; |
| |
| /// hasNUsesOrMore - Return true if this value has N users or more. This is |
| /// logically equivalent to getNumUses() >= N. |
| /// |
| bool hasNUsesOrMore(unsigned N) const; |
| |
| bool isUsedInBasicBlock(const BasicBlock *BB) const; |
| |
| /// getNumUses - This method computes the number of uses of this Value. This |
| /// is a linear time operation. Use hasOneUse, hasNUses, or hasMoreThanNUses |
| /// to check for specific values. |
| unsigned getNumUses() const; |
| |
| /// addUse - This method should only be used by the Use class. |
| /// |
| void addUse(Use &U) { U.addToList(&UseList); } |
| |
| /// An enumeration for keeping track of the concrete subclass of Value that |
| /// is actually instantiated. Values of this enumeration are kept in the |
| /// Value classes SubclassID field. They are used for concrete type |
| /// identification. |
| enum ValueTy { |
| ArgumentVal, // This is an instance of Argument |
| BasicBlockVal, // This is an instance of BasicBlock |
| FunctionVal, // This is an instance of Function |
| GlobalAliasVal, // This is an instance of GlobalAlias |
| GlobalVariableVal, // This is an instance of GlobalVariable |
| UndefValueVal, // This is an instance of UndefValue |
| ConstantExprVal, // This is an instance of ConstantExpr |
| ConstantAggregateZeroVal, // This is an instance of ConstantAggregateNull |
| ConstantIntVal, // This is an instance of ConstantInt |
| ConstantFPVal, // This is an instance of ConstantFP |
| ConstantArrayVal, // This is an instance of ConstantArray |
| ConstantStructVal, // This is an instance of ConstantStruct |
| ConstantVectorVal, // This is an instance of ConstantVector |
| ConstantPointerNullVal, // This is an instance of ConstantPointerNull |
| MDNodeVal, // This is an instance of MDNode |
| MDStringVal, // This is an instance of MDString |
| NamedMDNodeVal, // This is an instance of NamedMDNode |
| InlineAsmVal, // This is an instance of InlineAsm |
| PseudoSourceValueVal, // This is an instance of PseudoSourceValue |
| InstructionVal, // This is an instance of Instruction |
| |
| // Markers: |
| ConstantFirstVal = FunctionVal, |
| ConstantLastVal = ConstantPointerNullVal |
| }; |
| |
| /// getValueID - Return an ID for the concrete type of this object. This is |
| /// used to implement the classof checks. This should not be used for any |
| /// other purpose, as the values may change as LLVM evolves. Also, note that |
| /// for instructions, the Instruction's opcode is added to InstructionVal. So |
| /// this means three things: |
| /// # there is no value with code InstructionVal (no opcode==0). |
| /// # there are more possible values for the value type than in ValueTy enum. |
| /// # the InstructionVal enumerator must be the highest valued enumerator in |
| /// the ValueTy enum. |
| unsigned getValueID() const { |
| return SubclassID; |
| } |
| |
| /// hasSameSubclassOptionalData - Test whether the optional flags contained |
| /// in this value are equal to the optional flags in the given value. |
| bool hasSameSubclassOptionalData(const Value *V) const { |
| return SubclassOptionalData == V->SubclassOptionalData; |
| } |
| |
| /// intersectOptionalDataWith - Clear any optional flags in this value |
| /// that are not also set in the given value. |
| void intersectOptionalDataWith(const Value *V) { |
| SubclassOptionalData &= V->SubclassOptionalData; |
| } |
| |
| // Methods for support type inquiry through isa, cast, and dyn_cast: |
| static inline bool classof(const Value *) { |
| return true; // Values are always values. |
| } |
| |
| /// getRawType - This should only be used to implement the vmcore library. |
| /// |
| const Type *getRawType() const { return VTy.getRawType(); } |
| |
| /// stripPointerCasts - This method strips off any unneeded pointer |
| /// casts from the specified value, returning the original uncasted value. |
| /// Note that the returned value has pointer type if the specified value does. |
| Value *stripPointerCasts(); |
| const Value *stripPointerCasts() const { |
| return const_cast<Value*>(this)->stripPointerCasts(); |
| } |
| |
| /// getUnderlyingObject - This method strips off any GEP address adjustments |
| /// and pointer casts from the specified value, returning the original object |
| /// being addressed. Note that the returned value has pointer type if the |
| /// specified value does. |
| Value *getUnderlyingObject(); |
| const Value *getUnderlyingObject() const { |
| return const_cast<Value*>(this)->getUnderlyingObject(); |
| } |
| |
| /// 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 *DoPHITranslation(const BasicBlock *CurBB, const BasicBlock *PredBB); |
| |
| const Value *DoPHITranslation(const BasicBlock *CurBB, |
| const BasicBlock *PredBB) const{ |
| return const_cast<Value*>(this)->DoPHITranslation(CurBB, PredBB); |
| } |
| }; |
| |
| inline raw_ostream &operator<<(raw_ostream &OS, const Value &V) { |
| V.print(OS); |
| return OS; |
| } |
| |
| void Use::set(Value *V) { |
| if (Val) removeFromList(); |
| Val = V; |
| if (V) V->addUse(*this); |
| } |
| |
| |
| // isa - Provide some specializations of isa so that we don't have to include |
| // the subtype header files to test to see if the value is a subclass... |
| // |
| template <> inline bool isa_impl<Constant, Value>(const Value &Val) { |
| return Val.getValueID() >= Value::ConstantFirstVal && |
| Val.getValueID() <= Value::ConstantLastVal; |
| } |
| template <> inline bool isa_impl<Argument, Value>(const Value &Val) { |
| return Val.getValueID() == Value::ArgumentVal; |
| } |
| template <> inline bool isa_impl<InlineAsm, Value>(const Value &Val) { |
| return Val.getValueID() == Value::InlineAsmVal; |
| } |
| template <> inline bool isa_impl<Instruction, Value>(const Value &Val) { |
| return Val.getValueID() >= Value::InstructionVal; |
| } |
| template <> inline bool isa_impl<BasicBlock, Value>(const Value &Val) { |
| return Val.getValueID() == Value::BasicBlockVal; |
| } |
| template <> inline bool isa_impl<Function, Value>(const Value &Val) { |
| return Val.getValueID() == Value::FunctionVal; |
| } |
| template <> inline bool isa_impl<GlobalVariable, Value>(const Value &Val) { |
| return Val.getValueID() == Value::GlobalVariableVal; |
| } |
| template <> inline bool isa_impl<GlobalAlias, Value>(const Value &Val) { |
| return Val.getValueID() == Value::GlobalAliasVal; |
| } |
| template <> inline bool isa_impl<GlobalValue, Value>(const Value &Val) { |
| return isa<GlobalVariable>(Val) || isa<Function>(Val) || |
| isa<GlobalAlias>(Val); |
| } |
| |
| |
| // Value* is only 4-byte aligned. |
| template<> |
| class PointerLikeTypeTraits<Value*> { |
| typedef Value* PT; |
| public: |
| static inline void *getAsVoidPointer(PT P) { return P; } |
| static inline PT getFromVoidPointer(void *P) { |
| return static_cast<PT>(P); |
| } |
| enum { NumLowBitsAvailable = 2 }; |
| }; |
| |
| } // End llvm namespace |
| |
| #endif |