LLVM API Documentation

TargetMachine.h

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00001 //===-- llvm/Target/TargetMachine.h - Target Information --------*- C++ -*-===//
00002 //
00003 //                     The LLVM Compiler Infrastructure
00004 //
00005 // This file was developed by the LLVM research group and is distributed under
00006 // the University of Illinois Open Source License. See LICENSE.TXT for details.
00007 //
00008 //===----------------------------------------------------------------------===//
00009 //
00010 // This file describes the general parts of a Target machine.
00011 //
00012 //===----------------------------------------------------------------------===//
00013 
00014 #ifndef LLVM_TARGET_TARGETMACHINE_H
00015 #define LLVM_TARGET_TARGETMACHINE_H
00016 
00017 #include "llvm/Target/TargetInstrItineraries.h"
00018 #include <cassert>
00019 #include <string>
00020 
00021 namespace llvm {
00022 
00023 class TargetData;
00024 class TargetSubtarget;
00025 class TargetInstrInfo;
00026 class TargetInstrDescriptor;
00027 class TargetJITInfo;
00028 class TargetLowering;
00029 class TargetFrameInfo;
00030 class MachineCodeEmitter;
00031 class MRegisterInfo;
00032 class Module;
00033 class FunctionPassManager;
00034 class PassManager;
00035 class Pass;
00036 
00037 // Relocation model types.
00038 namespace Reloc {
00039   enum Model {
00040     Default,
00041     Static,
00042     PIC_,         // Cannot be named PIC due to collision with -DPIC
00043     DynamicNoPIC
00044   };
00045 }
00046 
00047 // Code model types.
00048 namespace CodeModel {
00049   enum Model {
00050     Default,
00051     Small,
00052     Kernel,
00053     Medium,
00054     Large
00055   };
00056 }
00057 
00058 //===----------------------------------------------------------------------===//
00059 ///
00060 /// TargetMachine - Primary interface to the complete machine description for
00061 /// the target machine.  All target-specific information should be accessible
00062 /// through this interface.
00063 ///
00064 class TargetMachine {
00065   const std::string Name;
00066 
00067   TargetMachine(const TargetMachine&);   // DO NOT IMPLEMENT
00068   void operator=(const TargetMachine&);  // DO NOT IMPLEMENT
00069 protected: // Can only create subclasses...
00070   TargetMachine(const std::string &name) : Name(name) { };
00071 
00072   /// This constructor is used for targets that support arbitrary TargetData
00073   /// layouts, like the C backend.  It initializes the TargetData to match that
00074   /// of the specified module.
00075   ///
00076   TargetMachine(const std::string &name, const Module &M);
00077 
00078   /// getSubtargetImpl - virtual method implemented by subclasses that returns
00079   /// a reference to that target's TargetSubtarget-derived member variable.
00080   virtual const TargetSubtarget *getSubtargetImpl() const { return 0; }
00081 public:
00082   virtual ~TargetMachine();
00083 
00084   /// getModuleMatchQuality - This static method should be implemented by
00085   /// targets to indicate how closely they match the specified module.  This is
00086   /// used by the LLC tool to determine which target to use when an explicit
00087   /// -march option is not specified.  If a target returns zero, it will never
00088   /// be chosen without an explicit -march option.
00089   static unsigned getModuleMatchQuality(const Module &M) { return 0; }
00090 
00091   /// getJITMatchQuality - This static method should be implemented by targets
00092   /// that provide JIT capabilities to indicate how suitable they are for
00093   /// execution on the current host.  If a value of 0 is returned, the target
00094   /// will not be used unless an explicit -march option is used.
00095   static unsigned getJITMatchQuality() { return 0; }
00096 
00097 
00098   const std::string &getName() const { return Name; }
00099 
00100   // Interfaces to the major aspects of target machine information:
00101   // -- Instruction opcode and operand information
00102   // -- Pipelines and scheduling information
00103   // -- Stack frame information
00104   // -- Selection DAG lowering information
00105   //
00106   virtual const TargetInstrInfo        *getInstrInfo() const { return 0; }
00107   virtual const TargetFrameInfo        *getFrameInfo() const { return 0; }
00108   virtual       TargetLowering    *getTargetLowering() const { return 0; }
00109   virtual const TargetData            *getTargetData() const { return 0; }
00110 
00111   /// getSubtarget - This method returns a pointer to the specified type of
00112   /// TargetSubtarget.  In debug builds, it verifies that the object being
00113   /// returned is of the correct type.
00114   template<typename STC> const STC &getSubtarget() const {
00115     const TargetSubtarget *TST = getSubtargetImpl();
00116     assert(TST && dynamic_cast<const STC*>(TST) &&
00117            "Not the right kind of subtarget!");
00118     return *static_cast<const STC*>(TST);
00119   }
00120 
00121   /// getRegisterInfo - If register information is available, return it.  If
00122   /// not, return null.  This is kept separate from RegInfo until RegInfo has
00123   /// details of graph coloring register allocation removed from it.
00124   ///
00125   virtual const MRegisterInfo*          getRegisterInfo() const { return 0; }
00126 
00127   /// getJITInfo - If this target supports a JIT, return information for it,
00128   /// otherwise return null.
00129   ///
00130   virtual TargetJITInfo *getJITInfo() { return 0; }
00131   
00132   /// getInstrItineraryData - Returns instruction itinerary data for the target
00133   /// or specific subtarget.
00134   ///
00135   virtual const InstrItineraryData getInstrItineraryData() const {  
00136     return InstrItineraryData();
00137   }
00138 
00139   /// getRelocationModel - Returns the code generation relocation model. The
00140   /// choices are static, PIC, and dynamic-no-pic, and target default.
00141   static Reloc::Model getRelocationModel();
00142 
00143   /// setRelocationModel - Sets the code generation relocation model.
00144   static void setRelocationModel(Reloc::Model Model);
00145 
00146   /// getCodeModel - Returns the code model. The choices are small, kernel,
00147   /// medium, large, and target default.
00148   static CodeModel::Model getCodeModel();
00149 
00150   /// setCodeModel - Sets the code model.
00151   static void setCodeModel(CodeModel::Model Model);
00152 
00153   /// CodeGenFileType - These enums are meant to be passed into
00154   /// addPassesToEmitFile to indicate what type of file to emit.
00155   enum CodeGenFileType {
00156     AssemblyFile, ObjectFile, DynamicLibrary
00157   };
00158 
00159   /// addPassesToEmitFile - Add passes to the specified pass manager to get
00160   /// the specified file emitted.  Typically this will involve several steps of
00161   /// code generation.  If Fast is set to true, the code generator should emit
00162   /// code as fast as possible, without regard for compile time.  This method
00163   /// should return true if emission of this file type is not supported.
00164   ///
00165   virtual bool addPassesToEmitFile(PassManager &PM, std::ostream &Out,
00166                                    CodeGenFileType FileType, bool Fast) {
00167     return true;
00168   }
00169 
00170   /// addPassesToEmitMachineCode - Add passes to the specified pass manager to
00171   /// get machine code emitted.  This uses a MachineCodeEmitter object to handle
00172   /// actually outputting the machine code and resolving things like the address
00173   /// of functions.  This method should returns true if machine code emission is
00174   /// not supported.
00175   ///
00176   virtual bool addPassesToEmitMachineCode(FunctionPassManager &PM,
00177                                           MachineCodeEmitter &MCE) {
00178     return true;
00179   }
00180 };
00181 
00182 } // End llvm namespace
00183 
00184 #endif