lib/Target/MBlaze/MBlazeMCCodeEmitter.cpp

   1 //===-- MBlazeMCCodeEmitter.cpp - Convert MBlaze code to machine code -----===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements the MBlazeMCCodeEmitter class.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #define DEBUG_TYPE "mccodeemitter"
  15 #include "MBlaze.h"
  16 #include "MBlazeInstrInfo.h"
  17 #include "llvm/MC/MCCodeEmitter.h"
  18 #include "llvm/MC/MCExpr.h"
  19 #include "llvm/MC/MCInst.h"
  20 #include "llvm/MC/MCSymbol.h"
  21 #include "llvm/MC/MCFixup.h"
  22 #include "llvm/ADT/Statistic.h"
  23 #include "llvm/Support/raw_ostream.h"
  24 using namespace llvm;
  25
  26 STATISTIC(MCNumEmitted, "Number of MC instructions emitted");
  27
  28 namespace {
  29 class MBlazeMCCodeEmitter : public MCCodeEmitter {
  30   MBlazeMCCodeEmitter(const MBlazeMCCodeEmitter &); // DO NOT IMPLEMENT
  31   void operator=(const MBlazeMCCodeEmitter &); // DO NOT IMPLEMENT
  32   const TargetMachine &TM;
  33   const TargetInstrInfo &TII;
  34   MCContext &Ctx;
  35
  36 public:
  37   MBlazeMCCodeEmitter(TargetMachine &tm, MCContext &ctx)
  38     : TM(tm), TII(*TM.getInstrInfo()), Ctx(ctx) {
  39   }
  40
  41   ~MBlazeMCCodeEmitter() {}
  42
  43   // getBinaryCodeForInstr - TableGen'erated function for getting the
  44   // binary encoding for an instruction.
  45   unsigned getBinaryCodeForInstr(const MCInst &MI) const;
  46
  47   /// getMachineOpValue - Return binary encoding of operand. If the machine
  48   /// operand requires relocation, record the relocation and return zero.
  49   unsigned getMachineOpValue(const MCInst &MI,const MCOperand &MO) const;
  50   unsigned getMachineOpValue(const MCInst &MI, unsigned OpIdx) const {
  51     return getMachineOpValue(MI, MI.getOperand(OpIdx));
  52   }
  53
  54   static unsigned GetMBlazeRegNum(const MCOperand &MO) {
  55     // FIXME: getMBlazeRegisterNumbering() is sufficient?
  56     assert(0 && "MBlazeMCCodeEmitter::GetMBlazeRegNum() not yet implemented.");
  57     return 0;
  58   }
  59
  60   void EmitByte(unsigned char C, unsigned &CurByte, raw_ostream &OS) const {
  61     // The MicroBlaze uses a bit reversed format so we need to reverse the
  62     // order of the bits. Taken from:
  63     // http://graphics.stanford.edu/~seander/bithacks.html
  64     C = ((C * 0x80200802ULL) & 0x0884422110ULL) * 0x0101010101ULL >> 32;
  65
  66     OS << (char)C;
  67     ++CurByte;
  68   }
  69
  70   void EmitRawByte(unsigned char C, unsigned &CurByte, raw_ostream &OS) const {
  71     OS << (char)C;
  72     ++CurByte;
  73   }
  74
  75   void EmitConstant(uint64_t Val, unsigned Size, unsigned &CurByte,
  76                     raw_ostream &OS) const {
  77     assert(Size <= 8 && "size too big in emit constant");
  78
  79     for (unsigned i = 0; i != Size; ++i) {
  80       EmitByte(Val & 255, CurByte, OS);
  81       Val >>= 8;
  82     }
  83   }
  84
  85   void EmitIMM(const MCOperand &imm, unsigned &CurByte, raw_ostream &OS) const;
  86   void EmitIMM(const MCInst &MI, unsigned &CurByte, raw_ostream &OS) const;
  87
  88   void EmitImmediate(const MCInst &MI, unsigned opNo, bool pcrel,
  89                      unsigned &CurByte, raw_ostream &OS,
  90                      SmallVectorImpl<MCFixup> &Fixups) const;
  91
  92   void EncodeInstruction(const MCInst &MI, raw_ostream &OS,
  93                          SmallVectorImpl<MCFixup> &Fixups) const;
  94 };
  95
  96 } // end anonymous namespace
  97
  98
  99 MCCodeEmitter *llvm::createMBlazeMCCodeEmitter(const Target &,
 100                                                TargetMachine &TM,
 101                                                MCContext &Ctx) {
 102   return new MBlazeMCCodeEmitter(TM, Ctx);
 103 }
 104
 105 /// getMachineOpValue - Return binary encoding of operand. If the machine
 106 /// operand requires relocation, record the relocation and return zero.
 107 unsigned MBlazeMCCodeEmitter::getMachineOpValue(const MCInst &MI,
 108                                              const MCOperand &MO) const {
 109   if (MO.isReg())
 110     return MBlazeRegisterInfo::getRegisterNumbering(MO.getReg());
 111   else if (MO.isImm())
 112     return static_cast<unsigned>(MO.getImm());
 113   else if (MO.isExpr())
 114       return 0; // The relocation has already been recorded at this point.
 115   else {
 116 #ifndef NDEBUG
 117     errs() << MO;
 118 #endif
 119     llvm_unreachable(0);
 120   }
 121   return 0;
 122 }
 123
 124 void MBlazeMCCodeEmitter::
 125 EmitIMM(const MCOperand &imm, unsigned &CurByte, raw_ostream &OS) const {
 126   int32_t val = (int32_t)imm.getImm();
 127   if (val > 32767 || val < -32768) {
 128     EmitByte(0x0D, CurByte, OS);
 129     EmitByte(0x00, CurByte, OS);
 130     EmitRawByte((val >> 24) & 0xFF, CurByte, OS);
 131     EmitRawByte((val >> 16) & 0xFF, CurByte, OS);
 132   }
 133 }
 134
 135 void MBlazeMCCodeEmitter::
 136 EmitIMM(const MCInst &MI, unsigned &CurByte,raw_ostream &OS) const {
 137   switch (MI.getOpcode()) {
 138   default: break;
 139
 140   case MBlaze::ADDIK32:
 141   case MBlaze::ORI32:
 142   case MBlaze::BRLID32:
 143     EmitByte(0x0D, CurByte, OS);
 144     EmitByte(0x00, CurByte, OS);
 145     EmitRawByte(0, CurByte, OS);
 146     EmitRawByte(0, CurByte, OS);
 147   }
 148 }
 149
 150 void MBlazeMCCodeEmitter::
 151 EmitImmediate(const MCInst &MI, unsigned opNo, bool pcrel, unsigned &CurByte,
 152               raw_ostream &OS, SmallVectorImpl<MCFixup> &Fixups) const {
 153   assert(MI.getNumOperands()>opNo && "Not enought operands for instruction");
 154
 155   MCOperand oper = MI.getOperand(opNo);
 156
 157   if (oper.isImm()) {
 158     EmitIMM(oper, CurByte, OS);
 159   } else if (oper.isExpr()) {
 160     MCFixupKind FixupKind;
 161     switch (MI.getOpcode()) {
 162     default:
 163       FixupKind = pcrel ? FK_PCRel_2 : FK_Data_2;
 164       Fixups.push_back(MCFixup::Create(0,oper.getExpr(),FixupKind));
 165       break;
 166     case MBlaze::ORI32:
 167     case MBlaze::ADDIK32:
 168     case MBlaze::BRLID32:
 169       FixupKind = pcrel ? FK_PCRel_4 : FK_Data_4;
 170       Fixups.push_back(MCFixup::Create(0,oper.getExpr(),FixupKind));
 171       break;
 172     }
 173   }
 174 }
 175
 176
 177
 178 void MBlazeMCCodeEmitter::
 179 EncodeInstruction(const MCInst &MI, raw_ostream &OS,
 180                   SmallVectorImpl<MCFixup> &Fixups) const {
 181   unsigned Opcode = MI.getOpcode();
 182   const TargetInstrDesc &Desc = TII.get(Opcode);
 183   uint64_t TSFlags = Desc.TSFlags;
 184   // Keep track of the current byte being emitted.
 185   unsigned CurByte = 0;
 186
 187   // Emit an IMM instruction if the instruction we are encoding requires it
 188   EmitIMM(MI,CurByte,OS);
 189
 190   switch ((TSFlags & MBlazeII::FormMask)) {
 191   default: break;
 192   case MBlazeII::FPseudo:
 193     // Pseudo instructions don't get encoded.
 194     return;
 195   case MBlazeII::FRRI:
 196     EmitImmediate(MI, 2, false, CurByte, OS, Fixups);
 197     break;
 198   case MBlazeII::FRIR:
 199     EmitImmediate(MI, 1, false, CurByte, OS, Fixups);
 200     break;
 201   case MBlazeII::FCRI:
 202     EmitImmediate(MI, 1, true, CurByte, OS, Fixups);
 203     break;
 204   case MBlazeII::FRCI:
 205     EmitImmediate(MI, 1, true, CurByte, OS, Fixups);
 206   case MBlazeII::FCCI:
 207     EmitImmediate(MI, 0, true, CurByte, OS, Fixups);
 208     break;
 209   }
 210
 211   ++MCNumEmitted;  // Keep track of the # of mi's emitted
 212   unsigned Value = getBinaryCodeForInstr(MI);
 213   EmitConstant(Value, 4, CurByte, OS);
 214 }
 215
 216 // FIXME: These #defines shouldn't be necessary. Instead, tblgen should
 217 // be able to generate code emitter helpers for either variant, like it
 218 // does for the AsmWriter.
 219 #define MBlazeCodeEmitter MBlazeMCCodeEmitter
 220 #define MachineInstr MCInst
 221 #include "MBlazeGenCodeEmitter.inc"
 222 #undef MBlazeCodeEmitter
 223 #undef MachineInstr