X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FConstant.h;h=7464dce3303fb0d0283120f969bdd66de4b03c03;hb=3a129c85920404e7ccdb7e655c89fa60a0309cfd;hp=e2b77a7e21a98788138d99c09f2792b6b488cce1;hpb=c5f24a2c2a16681f7816ac053c8f46a2692a3b7a;p=oota-llvm.git diff --git a/include/llvm/Constant.h b/include/llvm/Constant.h index e2b77a7e21a..7464dce3303 100644 --- a/include/llvm/Constant.h +++ b/include/llvm/Constant.h @@ -2,8 +2,8 @@ // // 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 is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // @@ -17,39 +17,87 @@ #include "llvm/User.h" namespace llvm { + class APInt; + template class SmallVectorImpl; + +/// 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. +/// Constants 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 + void operator=(const Constant &) LLVM_DELETED_FUNCTION; + Constant(const Constant &) LLVM_DELETED_FUNCTION; + virtual void anchor(); + protected: - Constant(const Type *Ty, ValueTy vty, Use *Ops, unsigned NumOps, - const std::string& Name = "") - : User(Ty, vty, Ops, NumOps, Name) {} + Constant(Type *ty, ValueTy vty, Use *Ops, unsigned NumOps) + : User(ty, vty, Ops, NumOps) {} void destroyConstantImpl(); public: - /// Static constructor to get a '0' constant of arbitrary type... - /// - static Constant *getNullValue(const Type *Ty); - /// isNullValue - Return true if this is the value that would be returned by /// getNullValue. - virtual bool isNullValue() const = 0; + bool isNullValue() const; - virtual void print(std::ostream &O) const; + /// isAllOnesValue - Return true if this is the value that would be returned by + /// getAllOnesValue. + bool isAllOnesValue() 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); - } + /// isNegativeZeroValue - Return true if the value is what would be returned + /// by getZeroValueForNegation. + bool isNegativeZeroValue() const; + + /// 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; + /// isConstantUsed - Return true if the constant has users other than constant + /// exprs and other dangling things. + bool isConstantUsed() const; + + enum PossibleRelocationsTy { + NoRelocation = 0, + LocalRelocation = 1, + GlobalRelocations = 2 + }; + + /// getRelocationInfo - This method classifies the entry according to + /// whether or not it may generate a relocation entry. This must be + /// conservative, so if it might codegen to a relocatable entry, it should say + /// so. The return values are: + /// + /// NoRelocation: This constant pool entry is guaranteed to never have a + /// relocation applied to it (because it holds a simple constant like + /// '4'). + /// LocalRelocation: This entry has relocations, but the entries are + /// guaranteed to be resolvable by the static linker, so the dynamic + /// linker will never see them. + /// GlobalRelocations: This entry may have arbitrary relocations. + /// + /// FIXME: This really should not be in VMCore. + PossibleRelocationsTy getRelocationInfo() const; + + /// getAggregateElement - For aggregates (struct/array/vector) return the + /// constant that corresponds to the specified element if possible, or null if + /// not. This can return null if the element index is a ConstantExpr, or if + /// 'this' is a constant expr. + Constant *getAggregateElement(unsigned Elt) const; + Constant *getAggregateElement(Constant *Elt) const; + /// 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 /// constant. Any constants on our Use list must also be destroy'd. The @@ -57,14 +105,14 @@ public: /// available cached constants. Implementations should call /// destroyConstantImpl as the last thing they do, to destroy all users and /// delete this. - virtual void destroyConstant() { assert(0 && "Not reached!"); } + virtual void destroyConstant() { llvm_unreachable("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() >= ConstantFirstVal && - V->getValueType() <= ConstantLastVal; + return V->getValueID() >= ConstantFirstVal && + V->getValueID() <= ConstantLastVal; } /// replaceUsesOfWithOnConstant - This method is a special form of @@ -83,13 +131,26 @@ public: // to be here to avoid link errors. assert(getNumOperands() == 0 && "replaceUsesOfWithOnConstant must be " "implemented for all constants that have operands!"); - assert(0 && "Constants that do not have operands cannot be using 'From'!"); + llvm_unreachable("Constants that do not have operands cannot be using " + "'From'!"); } - /// clearAllValueMaps - This method frees all internal memory used by the - /// constant subsystem, which can be used in environments where this memory - /// is otherwise reported as a leak. - static void clearAllValueMaps(); + static Constant *getNullValue(Type* Ty); + + /// @returns the value for an integer or vector of integer constant of the + /// given type that has all its bits set to true. + /// @brief Get the all ones value + static Constant *getAllOnesValue(Type* Ty); + + /// getIntegerValue - Return the value for an integer or pointer constant, + /// or a vector thereof, with the given scalar value. + static Constant *getIntegerValue(Type* Ty, const APInt &V); + + /// removeDeadConstantUsers - If there are any dead constant users dangling + /// off of this constant, remove them. This method is useful for clients + /// that want to check to see if a global is unused, but don't want to deal + /// with potentially dead constants hanging off of the globals. + void removeDeadConstantUsers() const; }; } // End llvm namespace