X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FConstant.h;h=d925fdb618ed96871847dcb0c9473d2dbea03478;hb=afba8fe662d65b25b4baf46bb26cc18e1f9cc0a5;hp=529603a559b4f61e9eccf642d707871be4d10c23;hpb=e45a76c85ba199d24432f2dc6453c10a7048c8c2;p=oota-llvm.git diff --git a/include/llvm/Constant.h b/include/llvm/Constant.h index 529603a559b..d925fdb618e 100644 --- a/include/llvm/Constant.h +++ b/include/llvm/Constant.h @@ -1,10 +1,10 @@ //===-- llvm/Constant.h - Constant class definition -------------*- C++ -*-===// -// +// // The LLVM Compiler Infrastructure // // This file was developed by the LLVM research group and is distributed under // the University of Illinois Open Source License. See LICENSE.TXT for details. -// +// //===----------------------------------------------------------------------===// // // This file contains the declaration of the Constant class. @@ -18,30 +18,67 @@ namespace llvm { +/// This is an important base class in LLVM. It provides the common facilities +/// of all constant values in an LLVM program. A constant is a value that is +/// immutable at runtime. Functions are constants because their address is +/// immutable. Same with global variables. +/// +/// All constants share the capabilities provided in this class. All constants +/// can have a null value. They can have an operand list. Constants can be +/// simple (integer and floating point values), complex (arrays and structures), +/// or expression based (computations yielding a constant value composed of +/// only certain operators and other constant values). +/// +/// Note that Constants are immutable (once created they never change) +/// and are fully shared by structural equivalence. This means that two +/// structurally equivalent constants will always have the same address. +/// Constant's are created on demand as needed and never deleted: thus clients +/// don't have to worry about the lifetime of the objects. +/// @brief LLVM Constant Representation class Constant : public User { + void operator=(const Constant &); // Do not implement + Constant(const Constant &); // Do not implement protected: - inline Constant(const Type *Ty) : User(Ty, Value::ConstantVal) {} - ~Constant() {} + Constant(const Type *Ty, ValueTy vty, Use *Ops, unsigned NumOps) + : User(Ty, vty, Ops, NumOps) {} void destroyConstantImpl(); public: - // setName - Specialize setName to handle symbol table majik... - virtual void setName(const std::string &name, SymbolTable *ST = 0); - /// Static constructor to get a '0' constant of arbitrary type... /// static Constant *getNullValue(const Type *Ty); + /// Static constructor to get a '-1' constant. This supports integers and + /// vectors. + /// + static Constant *getAllOnesValue(const Type *Ty); + /// isNullValue - Return true if this is the value that would be returned by /// getNullValue. virtual bool isNullValue() const = 0; virtual void print(std::ostream &O) const; + void print(std::ostream *O) const { if (O) print(*O); } + + /// canTrap - Return true if evaluation of this constant could trap. This is + /// true for things like constant expressions that could divide by zero. + bool canTrap() const; - /// isConstantExpr - Return true if this is a ConstantExpr - /// - virtual bool isConstantExpr() const { return false; } + /// ContaintsRelocations - Return true if the constant value contains + /// relocations which cannot be resolved at compile time. + bool ContainsRelocations() const; + // Specialize get/setOperand for Constant's as their operands are always + // constants as well. + Constant *getOperand(unsigned i) { + return static_cast(User::getOperand(i)); + } + const Constant *getOperand(unsigned i) const { + return static_cast(User::getOperand(i)); + } + void setOperand(unsigned i, Constant *C) { + User::setOperand(i, C); + } /// destroyConstant - Called if some element of this constant is no longer /// valid. At this point only other constants may be on the use_list for this @@ -50,20 +87,14 @@ public: /// available cached constants. Implementations should call /// destroyConstantImpl as the last thing they do, to destroy all users and /// delete this. - /// - /// Note that this call is only valid on non-primitive constants: You cannot - /// destroy an integer constant for example. This API is used to delete - /// constants that have ConstantPointerRef's embeded in them when the module - /// is deleted, and it is used by GlobalDCE to remove ConstantPointerRefs that - /// are unneeded, allowing globals to be DCE'd. - /// virtual void destroyConstant() { assert(0 && "Not reached!"); } - //// Methods for support type inquiry through isa, cast, and dyn_cast: static inline bool classof(const Constant *) { return true; } + static inline bool classof(const GlobalValue *) { return true; } static inline bool classof(const Value *V) { - return V->getValueType() == Value::ConstantVal; + return V->getValueID() >= ConstantFirstVal && + V->getValueID() <= ConstantLastVal; } /// replaceUsesOfWithOnConstant - This method is a special form of @@ -76,8 +107,7 @@ public: /// use Value::replaceAllUsesWith, which automatically dispatches to this /// method as needed. /// - virtual void replaceUsesOfWithOnConstant(Value *From, Value *To, - bool DisableChecking = false) { + virtual void replaceUsesOfWithOnConstant(Value *, Value *, Use *) { // Provide a default implementation for constants (like integers) that // cannot use any other values. This cannot be called at runtime, but needs // to be here to avoid link errors. @@ -85,6 +115,13 @@ public: "implemented for all constants that have operands!"); assert(0 && "Constants that do not have operands cannot be using 'From'!"); } + + /// getStringValue - Turn an LLVM constant pointer that eventually points to a + /// global into a string value. Return an empty string if we can't do it. + /// Parameter Chop determines if the result is chopped at the first null + /// terminator. + /// + std::string getStringValue(bool Chop = true, unsigned Offset = 0); }; } // End llvm namespace