X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FCodeGen%2FMachineConstantPool.h;h=c82935a251b77ef8a978bb3fe1a6bfa04013e8e3;hb=ea45c5101b9dd048f7f401d3157a3c35f3bcd9cb;hp=0e6c642e8e50626db153128c1ad6b093d4055231;hpb=ea61c358720aa6c7a159d51658b34276316aa841;p=oota-llvm.git diff --git a/include/llvm/CodeGen/MachineConstantPool.h b/include/llvm/CodeGen/MachineConstantPool.h index 0e6c642e8e5..c82935a251b 100644 --- a/include/llvm/CodeGen/MachineConstantPool.h +++ b/include/llvm/CodeGen/MachineConstantPool.h @@ -2,58 +2,175 @@ // // 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. // //===----------------------------------------------------------------------===// // -// The MachineConstantPool class keeps track of constants referenced by a -// function which must be spilled to memory. This is used for constants which -// are unable to be used directly as operands to instructions, which typically -// include floating point and large integer constants. -// -// Instructions reference the address of these constant pool constants through -// the use of MO_ConstantPoolIndex values. When emitting assembly or machine -// code, these virtual address references are converted to refer to the -// address of the function constant pool values. +/// @file +/// This file declares the MachineConstantPool class which is an abstract +/// constant pool to keep track of constants referenced by a function. // //===----------------------------------------------------------------------===// #ifndef LLVM_CODEGEN_MACHINECONSTANTPOOL_H #define LLVM_CODEGEN_MACHINECONSTANTPOOL_H +#include "llvm/ADT/DenseSet.h" +#include "llvm/MC/SectionKind.h" +#include +#include #include namespace llvm { class Constant; +class FoldingSetNodeID; +class DataLayout; +class TargetMachine; +class Type; +class MachineConstantPool; +class raw_ostream; + +/// Abstract base class for all machine specific constantpool value subclasses. +/// +class MachineConstantPoolValue { + virtual void anchor(); + Type *Ty; -class MachineConstantPool { - std::vector Constants; public: + explicit MachineConstantPoolValue(Type *ty) : Ty(ty) {} + virtual ~MachineConstantPoolValue() {} - /// getConstantPoolIndex - Create a new entry in the constant pool or return - /// an existing one. + /// getType - get type of this MachineConstantPoolValue. /// - unsigned getConstantPoolIndex(Constant *C) { - // Check to see if we already have this constant. - // - // FIXME, this could be made much more efficient for large constant pools. - for (unsigned i = 0, e = Constants.size(); i != e; ++i) - if (Constants[i] == C) - return i; - Constants.push_back(C); - return Constants.size()-1; + Type *getType() const { return Ty; } + + /// 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 the same as Constant::getRelocationInfo(). + virtual unsigned getRelocationInfo() const = 0; + + virtual int getExistingMachineCPValue(MachineConstantPool *CP, + unsigned Alignment) = 0; + + virtual void addSelectionDAGCSEId(FoldingSetNodeID &ID) = 0; + + /// print - Implement operator<< + virtual void print(raw_ostream &O) const = 0; +}; + +inline raw_ostream &operator<<(raw_ostream &OS, + const MachineConstantPoolValue &V) { + V.print(OS); + return OS; +} + +/// This class is a data container for one entry in a MachineConstantPool. +/// It contains a pointer to the value and an offset from the start of +/// the constant pool. +/// @brief An entry in a MachineConstantPool +class MachineConstantPoolEntry { +public: + /// The constant itself. + union { + const Constant *ConstVal; + MachineConstantPoolValue *MachineCPVal; + } Val; + + /// The required alignment for this entry. The top bit is set when Val is + /// a target specific MachineConstantPoolValue. + unsigned Alignment; + + MachineConstantPoolEntry(const Constant *V, unsigned A) + : Alignment(A) { + Val.ConstVal = V; + } + MachineConstantPoolEntry(MachineConstantPoolValue *V, unsigned A) + : Alignment(A) { + Val.MachineCPVal = V; + Alignment |= 1U << (sizeof(unsigned) * CHAR_BIT - 1); + } + + /// isMachineConstantPoolEntry - Return true if the MachineConstantPoolEntry + /// is indeed a target specific constantpool entry, not a wrapper over a + /// Constant. + bool isMachineConstantPoolEntry() const { + return (int)Alignment < 0; } - const std::vector &getConstants() const { return Constants; } + int getAlignment() const { + return Alignment & ~(1 << (sizeof(unsigned) * CHAR_BIT - 1)); + } + + Type *getType() const; + + /// 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: + /// + /// 0: This constant pool entry is guaranteed to never have a relocation + /// applied to it (because it holds a simple constant like '4'). + /// 1: This entry has relocations, but the entries are guaranteed to be + /// resolvable by the static linker, so the dynamic linker will never see + /// them. + /// 2: This entry may have arbitrary relocations. + unsigned getRelocationInfo() const; + + SectionKind getSectionKind(const DataLayout *DL) const; +}; + +/// The MachineConstantPool class keeps track of constants referenced by a +/// function which must be spilled to memory. This is used for constants which +/// are unable to be used directly as operands to instructions, which typically +/// include floating point and large integer constants. +/// +/// Instructions reference the address of these constant pool constants through +/// the use of MO_ConstantPoolIndex values. When emitting assembly or machine +/// code, these virtual address references are converted to refer to the +/// address of the function constant pool values. +/// @brief The machine constant pool. +class MachineConstantPool { + unsigned PoolAlignment; ///< The alignment for the pool. + std::vector Constants; ///< The pool of constants. + /// MachineConstantPoolValues that use an existing MachineConstantPoolEntry. + DenseSet MachineCPVsSharingEntries; + const DataLayout &DL; + + const DataLayout &getDataLayout() const { return DL; } + +public: + /// @brief The only constructor. + explicit MachineConstantPool(const DataLayout &DL) + : PoolAlignment(1), DL(DL) {} + ~MachineConstantPool(); + + /// getConstantPoolAlignment - Return the alignment required by + /// the whole constant pool, of which the first element must be aligned. + unsigned getConstantPoolAlignment() const { return PoolAlignment; } + + /// getConstantPoolIndex - Create a new entry in the constant pool or return + /// an existing one. User must specify the minimum required alignment for + /// the object. + unsigned getConstantPoolIndex(const Constant *C, unsigned Alignment); + unsigned getConstantPoolIndex(MachineConstantPoolValue *V, + unsigned Alignment); + + /// isEmpty - Return true if this constant pool contains no constants. + bool isEmpty() const { return Constants.empty(); } + + const std::vector &getConstants() const { + return Constants; + } /// print - Used by the MachineFunction printer to print information about - /// stack objects. Implemented in MachineFunction.cpp + /// constant pool objects. Implemented in MachineFunction.cpp /// - void print(std::ostream &OS) const; + void print(raw_ostream &OS) const; - /// dump - Call print(std::cerr) to be called from the debugger. + /// dump - Call print(cerr) to be called from the debugger. void dump() const; };