X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FConstant.h;h=601b37bb64e4df165db1a12111b1d1d953de845f;hb=d6a49773ffbe35847baa7a68773ebbb326120dd0;hp=e48a9c5d74078fc457c25d1d26b1a1ec307c06ea;hpb=ed455c8fa25dd37a13b33f0afa66be03ac49b5bb;p=oota-llvm.git diff --git a/include/llvm/Constant.h b/include/llvm/Constant.h index e48a9c5d740..601b37bb64e 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. // //===----------------------------------------------------------------------===// // @@ -17,6 +17,9 @@ #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 @@ -32,57 +35,62 @@ namespace llvm { /// 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 +/// 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 + protected: - Constant(const Type *Ty, ValueTy vty, Use *Ops, unsigned NumOps) - : User(Ty, vty, Ops, NumOps) {} + Constant(Type *ty, ValueTy vty, Use *Ops, unsigned NumOps) + : User(ty, vty, Ops, NumOps) {} void destroyConstantImpl(); - static void destroyThis(Constant*v) { - User::destroyThis(v); - } - friend class Value; public: - /// 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; + bool isNullValue() const; + + /// isNegativeZeroValue - Return true if the value is what would be returned + /// by getZeroValueForNegation. + bool isNegativeZeroValue() const; - 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; - /// 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); - } + /// 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; + + /// getVectorElements - This method, which is only valid on constant of vector + /// type, returns the elements of the vector in the specified smallvector. + /// This handles breaking down a vector undef into undef elements, etc. For + /// constant exprs and other cases we can't handle, we return an empty vector. + void getVectorElements(SmallVectorImpl &Elts) 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 @@ -119,13 +127,23 @@ public: "implemented for all constants that have operands!"); assert(0 && "Constants that do not have operands cannot be using 'From'!"); } + + static Constant *getNullValue(Type* Ty); + + /// @returns the value for an 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); - /// 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); + /// 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