lib/Target/PowerPC/PPCSubtarget.h

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

#ifndef POWERPCSUBTARGET_H
#define POWERPCSUBTARGET_H

#include "llvm/Target/TargetSubtargetInfo.h"
#include "llvm/MC/MCInstrItineraries.h"
#include "llvm/ADT/Triple.h"
#include <string>

#define GET_SUBTARGETINFO_HEADER
#include "PPCGenSubtargetInfo.inc"

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

namespace llvm {
class StringRef;

namespace PPC {
  // -m directive values.
  enum {
    DIR_NONE,
    DIR_32,
    DIR_440, 
    DIR_601, 
    DIR_602, 
    DIR_603, 
    DIR_7400,
    DIR_750, 
    DIR_970, 
    DIR_64  
  };
}

class GlobalValue;
class TargetMachine;
  
class PPCSubtarget : public PPCGenSubtargetInfo {
protected:
  /// 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;

  /// 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 IsBookE;
  bool HasLazyResolverStubs;
  bool IsJITCodeModel;
  
  /// TargetTriple - What processor and OS we're targeting.
  Triple TargetTriple;

public:
  /// This constructor initializes the data members to match that
  /// of the specified triple.
  ///
  PPCSubtarget(const std::string &TT, const std::string &CPU,
               const std::string &FS, bool is64Bit);
  
  /// ParseSubtargetFeatures - Parses features string setting specified 
  /// subtarget options.  Definition of function is auto generated by tblgen.
  void ParseSubtargetFeatures(StringRef CPU, StringRef FS);
  
  /// 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 {
    // Note, the alignment values for f64 and i64 on ppc64 in Darwin
    // documentation are wrong; these are correct (i.e. "what gcc does").
    return isPPC64() ? "E-p:64:64-f64:64:64-i64:64:64-f128:64:128-n32:64"
                     : "E-p:32:32-f64:64:64-i64:64:64-f128:64:128-n32";
  }

  /// 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 TargetMachine &TM) const;
  
  // isJITCodeModel - True if we're generating code for the JIT
  bool isJITCodeModel() const { return IsJITCodeModel; }

  // Specific obvious features.
  bool hasFSQRT() const { return HasFSQRT; }
  bool hasSTFIWX() const { return HasSTFIWX; }
  bool hasAltivec() const { return HasAltivec; }
  bool isGigaProcessor() const { return IsGigaProcessor; }
  bool isBookE() const { return IsBookE; }

  const Triple &getTargetTriple() const { return TargetTriple; }

  /// isDarwin - True if this is any darwin platform.
  bool isDarwin() const { return TargetTriple.isMacOSX(); }

  bool isDarwinABI() const { return isDarwin(); }
  bool isSVR4ABI() const { return !isDarwin(); }

  /// enablePostRAScheduler - True at 'More' optimization.
  bool enablePostRAScheduler(CodeGenOpt::Level OptLevel,
                             TargetSubtargetInfo::AntiDepBreakMode& Mode,
                             RegClassVector& CriticalPathRCs) const;
};
} // End llvm namespace

#endif