lib/Target/PowerPC/PPCSubtarget.h

//=====-- PPCSubtarget.h - Define Subtarget for the PPC -------*- C++ -*--====//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by Nate Begeman and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares the PowerPC specific subclass of TargetSubtarget.
//
//===----------------------------------------------------------------------===//

#ifndef POWERPCSUBTARGET_H
#define POWERPCSUBTARGET_H

#include "llvm/Target/TargetInstrItineraries.h"
#include "llvm/Target/TargetSubtarget.h"

#include <string>

// GCC #defines PPC on Linux but we use it as our namespace name
#undef PPC

namespace llvm {

namespace PPC {
  // -m directive values.
  enum {
    DIR_32,
    DIR_601, 
    DIR_602, 
    DIR_603, 
    DIR_7400,
    DIR_750, 
    DIR_970, 
    DIR_64  
  };
}

class Module;
class GlobalValue;
class TargetMachine;
  
class PPCSubtarget : public TargetSubtarget {
public:
  enum AsmWriterFlavorTy {
    OldMnemonic, NewMnemonic, Unset
  };
protected:
  const TargetMachine &TM;
  
  /// stackAlignment - The minimum alignment known to hold of the stack frame on
  /// entry to the function and which must be maintained by every function.
  unsigned StackAlignment;
  
  /// Selected instruction itineraries (one entry per itinerary class.)
  InstrItineraryData InstrItins;
  
  /// Which cpu directive was used.
  unsigned DarwinDirective;

  /// AsmFlavor - Which PPC asm dialect to use.
  AsmWriterFlavorTy AsmFlavor;

  /// Used by the ISel to turn in optimizations for POWER4-derived architectures
  bool IsGigaProcessor;
  bool Has64BitSupport;
  bool Use64BitRegs;
  bool IsPPC64;
  bool HasAltivec;
  bool HasFSQRT;
  bool HasSTFIWX;
  bool IsDarwin;
  bool HasLazyResolverStubs;
public:
  /// This constructor initializes the data members to match that
  /// of the specified module.
  ///
  PPCSubtarget(const TargetMachine &TM, const Module &M,
               const std::string &FS, bool is64Bit);
  
  /// ParseSubtargetFeatures - Parses features string setting specified 
  /// subtarget options.  Definition of function is auto generated by tblgen.
  void ParseSubtargetFeatures(const std::string &FS, const std::string &CPU);
  
  /// SetJITMode - This is called to inform the subtarget info that we are
  /// producing code for the JIT.
  void SetJITMode();

  /// getStackAlignment - Returns the minimum alignment known to hold of the
  /// stack frame on entry to the function and which must be maintained by every
  /// function for this subtarget.
  unsigned getStackAlignment() const { return StackAlignment; }
  
  /// getDarwinDirective - Returns the -m directive specified for the cpu.
  ///
  unsigned getDarwinDirective() const { return DarwinDirective; }
  
  /// getInstrItins - Return the instruction itineraies based on subtarget 
  /// selection.
  const InstrItineraryData &getInstrItineraryData() const { return InstrItins; }

  /// getTargetDataString - Return the pointer size and type alignment
  /// properties of this subtarget.
  const char *getTargetDataString() const {
    return isPPC64() ? "E-p:64:64-f64:32:64-i64:32:64"
                     : "E-p:32:32-f64:32:64-i64:32:64";
  }

  /// isPPC64 - Return true if we are generating code for 64-bit pointer mode.
  ///
  bool isPPC64() const { return IsPPC64; }
  
  /// has64BitSupport - Return true if the selected CPU supports 64-bit
  /// instructions, regardless of whether we are in 32-bit or 64-bit mode.
  bool has64BitSupport() const { return Has64BitSupport; }
  
  /// use64BitRegs - Return true if in 64-bit mode or if we should use 64-bit
  /// registers in 32-bit mode when possible.  This can only true if
  /// has64BitSupport() returns true.
  bool use64BitRegs() const { return Use64BitRegs; }
  
  /// hasLazyResolverStub - Return true if accesses to the specified global have
  /// to go through a dyld lazy resolution stub.  This means that an extra load
  /// is required to get the address of the global.
  bool hasLazyResolverStub(const GlobalValue *GV) const;
  
  // Specific obvious features.
  bool hasFSQRT() const { return HasFSQRT; }
  bool hasSTFIWX() const { return HasSTFIWX; }
  bool hasAltivec() const { return HasAltivec; }
  bool isGigaProcessor() const { return IsGigaProcessor; }

  bool isDarwin() const { return IsDarwin; }

  unsigned getAsmFlavor() const {
    return AsmFlavor != Unset ? unsigned(AsmFlavor) : 0;
  }
};
} // End llvm namespace

#endif