llvm/lib/Target/SystemZ/Disassembler/SystemZDisassembler.cpp

   1 //===-- SystemZDisassembler.cpp - Disassembler for SystemZ ------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "MCTargetDesc/SystemZMCTargetDesc.h"
  10 #include "TargetInfo/SystemZTargetInfo.h"
  11 #include "llvm/MC/MCDecoderOps.h"
  12 #include "llvm/MC/MCDisassembler/MCDisassembler.h"
  13 #include "llvm/MC/MCInst.h"
  14 #include "llvm/MC/MCSubtargetInfo.h"
  15 #include "llvm/MC/TargetRegistry.h"
  16 #include "llvm/Support/MathExtras.h"
  17 #include <cassert>
  18 #include <cstdint>
  19
  20 using namespace llvm;
  21
  22 #define DEBUG_TYPE "systemz-disassembler"
  23
  24 typedef MCDisassembler::DecodeStatus DecodeStatus;
  25
  26 namespace {
  27
  28 class SystemZDisassembler : public MCDisassembler {
  29 public:
  30   SystemZDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx)
  31     : MCDisassembler(STI, Ctx) {}
  32   ~SystemZDisassembler() override = default;
  33
  34   DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
  35                               ArrayRef<uint8_t> Bytes, uint64_t Address,
  36                               raw_ostream &CStream) const override;
  37 };
  38
  39 } // end anonymous namespace
  40
  41 static MCDisassembler *createSystemZDisassembler(const Target &T,
  42                                                  const MCSubtargetInfo &STI,
  43                                                  MCContext &Ctx) {
  44   return new SystemZDisassembler(STI, Ctx);
  45 }
  46
  47 // NOLINTNEXTLINE(readability-identifier-naming)
  48 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeSystemZDisassembler() {
  49   // Register the disassembler.
  50   TargetRegistry::RegisterMCDisassembler(getTheSystemZTarget(),
  51                                          createSystemZDisassembler);
  52 }
  53
  54 /// tryAddingSymbolicOperand - trys to add a symbolic operand in place of the
  55 /// immediate Value in the MCInst.
  56 ///
  57 /// @param Value      - The immediate Value, has had any PC adjustment made by
  58 ///                     the caller.
  59 /// @param isBranch   - If the instruction is a branch instruction
  60 /// @param Address    - The starting address of the instruction
  61 /// @param Offset     - The byte offset to this immediate in the instruction
  62 /// @param Width      - The byte width of this immediate in the instruction
  63 ///
  64 /// If the getOpInfo() function was set when setupForSymbolicDisassembly() was
  65 /// called then that function is called to get any symbolic information for the
  66 /// immediate in the instruction using the Address, Offset and Width.  If that
  67 /// returns non-zero then the symbolic information it returns is used to create
  68 /// an MCExpr and that is added as an operand to the MCInst.  If getOpInfo()
  69 /// returns zero and isBranch is true then a symbol look up for immediate Value
  70 /// is done and if a symbol is found an MCExpr is created with that, else
  71 /// an MCExpr with the immediate Value is created.  This function returns true
  72 /// if it adds an operand to the MCInst and false otherwise.
  73 static bool tryAddingSymbolicOperand(int64_t Value, bool IsBranch,
  74                                      uint64_t Address, uint64_t Offset,
  75                                      uint64_t Width, MCInst &MI,
  76                                      const MCDisassembler *Decoder) {
  77   return Decoder->tryAddingSymbolicOperand(MI, Value, Address, IsBranch, Offset,
  78                                            Width, /*InstSize=*/0);
  79 }
  80
  81 static DecodeStatus decodeRegisterClass(MCInst &Inst, uint64_t RegNo,
  82                                         const unsigned *Regs, unsigned Size,
  83                                         bool IsAddr = false) {
  84   assert(RegNo < Size && "Invalid register");
  85   if (IsAddr && RegNo == 0) {
  86     RegNo = SystemZ::NoRegister;
  87   } else {
  88     RegNo = Regs[RegNo];
  89     if (RegNo == 0)
  90       return MCDisassembler::Fail;
  91   }
  92   Inst.addOperand(MCOperand::createReg(RegNo));
  93   return MCDisassembler::Success;
  94 }
  95
  96 static DecodeStatus DecodeGR32BitRegisterClass(MCInst &Inst, uint64_t RegNo,
  97                                                uint64_t Address,
  98                                                const MCDisassembler *Decoder) {
  99   return decodeRegisterClass(Inst, RegNo, SystemZMC::GR32Regs, 16);
 100 }
 101
 102 static DecodeStatus DecodeGRH32BitRegisterClass(MCInst &Inst, uint64_t RegNo,
 103                                                 uint64_t Address,
 104                                                 const MCDisassembler *Decoder) {
 105   return decodeRegisterClass(Inst, RegNo, SystemZMC::GRH32Regs, 16);
 106 }
 107
 108 static DecodeStatus DecodeGR64BitRegisterClass(MCInst &Inst, uint64_t RegNo,
 109                                                uint64_t Address,
 110                                                const MCDisassembler *Decoder) {
 111   return decodeRegisterClass(Inst, RegNo, SystemZMC::GR64Regs, 16);
 112 }
 113
 114 static DecodeStatus DecodeGR128BitRegisterClass(MCInst &Inst, uint64_t RegNo,
 115                                                 uint64_t Address,
 116                                                 const MCDisassembler *Decoder) {
 117   return decodeRegisterClass(Inst, RegNo, SystemZMC::GR128Regs, 16);
 118 }
 119
 120 static DecodeStatus
 121 DecodeADDR32BitRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address,
 122                              const MCDisassembler *Decoder) {
 123   return decodeRegisterClass(Inst, RegNo, SystemZMC::GR32Regs, 16, true);
 124 }
 125
 126 static DecodeStatus
 127 DecodeADDR64BitRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address,
 128                              const MCDisassembler *Decoder) {
 129   return decodeRegisterClass(Inst, RegNo, SystemZMC::GR64Regs, 16, true);
 130 }
 131
 132 static DecodeStatus DecodeFP32BitRegisterClass(MCInst &Inst, uint64_t RegNo,
 133                                                uint64_t Address,
 134                                                const MCDisassembler *Decoder) {
 135   return decodeRegisterClass(Inst, RegNo, SystemZMC::FP32Regs, 16);
 136 }
 137
 138 static DecodeStatus DecodeFP64BitRegisterClass(MCInst &Inst, uint64_t RegNo,
 139                                                uint64_t Address,
 140                                                const MCDisassembler *Decoder) {
 141   return decodeRegisterClass(Inst, RegNo, SystemZMC::FP64Regs, 16);
 142 }
 143
 144 static DecodeStatus DecodeFP128BitRegisterClass(MCInst &Inst, uint64_t RegNo,
 145                                                 uint64_t Address,
 146                                                 const MCDisassembler *Decoder) {
 147   return decodeRegisterClass(Inst, RegNo, SystemZMC::FP128Regs, 16);
 148 }
 149
 150 static DecodeStatus DecodeVR32BitRegisterClass(MCInst &Inst, uint64_t RegNo,
 151                                                uint64_t Address,
 152                                                const MCDisassembler *Decoder) {
 153   return decodeRegisterClass(Inst, RegNo, SystemZMC::VR32Regs, 32);
 154 }
 155
 156 static DecodeStatus DecodeVR64BitRegisterClass(MCInst &Inst, uint64_t RegNo,
 157                                                uint64_t Address,
 158                                                const MCDisassembler *Decoder) {
 159   return decodeRegisterClass(Inst, RegNo, SystemZMC::VR64Regs, 32);
 160 }
 161
 162 static DecodeStatus DecodeVR128BitRegisterClass(MCInst &Inst, uint64_t RegNo,
 163                                                 uint64_t Address,
 164                                                 const MCDisassembler *Decoder) {
 165   return decodeRegisterClass(Inst, RegNo, SystemZMC::VR128Regs, 32);
 166 }
 167
 168 static DecodeStatus DecodeAR32BitRegisterClass(MCInst &Inst, uint64_t RegNo,
 169                                                uint64_t Address,
 170                                                const MCDisassembler *Decoder) {
 171   return decodeRegisterClass(Inst, RegNo, SystemZMC::AR32Regs, 16);
 172 }
 173
 174 static DecodeStatus DecodeCR64BitRegisterClass(MCInst &Inst, uint64_t RegNo,
 175                                                uint64_t Address,
 176                                                const MCDisassembler *Decoder) {
 177   return decodeRegisterClass(Inst, RegNo, SystemZMC::CR64Regs, 16);
 178 }
 179
 180 template<unsigned N>
 181 static DecodeStatus decodeUImmOperand(MCInst &Inst, uint64_t Imm) {
 182   if (!isUInt<N>(Imm))
 183     return MCDisassembler::Fail;
 184   Inst.addOperand(MCOperand::createImm(Imm));
 185   return MCDisassembler::Success;
 186 }
 187
 188 template<unsigned N>
 189 static DecodeStatus decodeSImmOperand(MCInst &Inst, uint64_t Imm) {
 190   if (!isUInt<N>(Imm))
 191     return MCDisassembler::Fail;
 192   Inst.addOperand(MCOperand::createImm(SignExtend64<N>(Imm)));
 193   return MCDisassembler::Success;
 194 }
 195
 196 static DecodeStatus decodeU1ImmOperand(MCInst &Inst, uint64_t Imm,
 197                                        uint64_t Address,
 198                                        const MCDisassembler *Decoder) {
 199   return decodeUImmOperand<1>(Inst, Imm);
 200 }
 201
 202 static DecodeStatus decodeU2ImmOperand(MCInst &Inst, uint64_t Imm,
 203                                        uint64_t Address,
 204                                        const MCDisassembler *Decoder) {
 205   return decodeUImmOperand<2>(Inst, Imm);
 206 }
 207
 208 static DecodeStatus decodeU3ImmOperand(MCInst &Inst, uint64_t Imm,
 209                                        uint64_t Address,
 210                                        const MCDisassembler *Decoder) {
 211   return decodeUImmOperand<3>(Inst, Imm);
 212 }
 213
 214 static DecodeStatus decodeU4ImmOperand(MCInst &Inst, uint64_t Imm,
 215                                        uint64_t Address,
 216                                        const MCDisassembler *Decoder) {
 217   return decodeUImmOperand<4>(Inst, Imm);
 218 }
 219
 220 static DecodeStatus decodeU8ImmOperand(MCInst &Inst, uint64_t Imm,
 221                                        uint64_t Address,
 222                                        const MCDisassembler *Decoder) {
 223   return decodeUImmOperand<8>(Inst, Imm);
 224 }
 225
 226 static DecodeStatus decodeU12ImmOperand(MCInst &Inst, uint64_t Imm,
 227                                         uint64_t Address,
 228                                         const MCDisassembler *Decoder) {
 229   return decodeUImmOperand<12>(Inst, Imm);
 230 }
 231
 232 static DecodeStatus decodeU16ImmOperand(MCInst &Inst, uint64_t Imm,
 233                                         uint64_t Address,
 234                                         const MCDisassembler *Decoder) {
 235   return decodeUImmOperand<16>(Inst, Imm);
 236 }
 237
 238 static DecodeStatus decodeU32ImmOperand(MCInst &Inst, uint64_t Imm,
 239                                         uint64_t Address,
 240                                         const MCDisassembler *Decoder) {
 241   return decodeUImmOperand<32>(Inst, Imm);
 242 }
 243
 244 static DecodeStatus decodeS8ImmOperand(MCInst &Inst, uint64_t Imm,
 245                                        uint64_t Address,
 246                                        const MCDisassembler *Decoder) {
 247   return decodeSImmOperand<8>(Inst, Imm);
 248 }
 249
 250 static DecodeStatus decodeS16ImmOperand(MCInst &Inst, uint64_t Imm,
 251                                         uint64_t Address,
 252                                         const MCDisassembler *Decoder) {
 253   return decodeSImmOperand<16>(Inst, Imm);
 254 }
 255
 256 static DecodeStatus decodeS20ImmOperand(MCInst &Inst, uint64_t Imm,
 257                                         uint64_t Address,
 258                                         const MCDisassembler *Decoder) {
 259   return decodeSImmOperand<20>(Inst, Imm);
 260 }
 261
 262 static DecodeStatus decodeS32ImmOperand(MCInst &Inst, uint64_t Imm,
 263                                         uint64_t Address,
 264                                         const MCDisassembler *Decoder) {
 265   return decodeSImmOperand<32>(Inst, Imm);
 266 }
 267
 268 template <unsigned N>
 269 static DecodeStatus decodeLenOperand(MCInst &Inst, uint64_t Imm,
 270                                      uint64_t Address,
 271                                      const MCDisassembler *Decoder) {
 272   if (!isUInt<N>(Imm))
 273     return MCDisassembler::Fail;
 274   Inst.addOperand(MCOperand::createImm(Imm + 1));
 275   return MCDisassembler::Success;
 276 }
 277
 278 template <unsigned N>
 279 static DecodeStatus decodePCDBLOperand(MCInst &Inst, uint64_t Imm,
 280                                        uint64_t Address, bool isBranch,
 281                                        const MCDisassembler *Decoder) {
 282   assert(isUInt<N>(Imm) && "Invalid PC-relative offset");
 283   uint64_t Value = SignExtend64<N>(Imm) * 2 + Address;
 284
 285   if (!tryAddingSymbolicOperand(Value, isBranch, Address, 2, N / 8,
 286                                 Inst, Decoder))
 287     Inst.addOperand(MCOperand::createImm(Value));
 288
 289   return MCDisassembler::Success;
 290 }
 291
 292 static DecodeStatus decodePC12DBLBranchOperand(MCInst &Inst, uint64_t Imm,
 293                                                uint64_t Address,
 294                                                const MCDisassembler *Decoder) {
 295   return decodePCDBLOperand<12>(Inst, Imm, Address, true, Decoder);
 296 }
 297
 298 static DecodeStatus decodePC16DBLBranchOperand(MCInst &Inst, uint64_t Imm,
 299                                                uint64_t Address,
 300                                                const MCDisassembler *Decoder) {
 301   return decodePCDBLOperand<16>(Inst, Imm, Address, true, Decoder);
 302 }
 303
 304 static DecodeStatus decodePC24DBLBranchOperand(MCInst &Inst, uint64_t Imm,
 305                                                uint64_t Address,
 306                                                const MCDisassembler *Decoder) {
 307   return decodePCDBLOperand<24>(Inst, Imm, Address, true, Decoder);
 308 }
 309
 310 static DecodeStatus decodePC32DBLBranchOperand(MCInst &Inst, uint64_t Imm,
 311                                                uint64_t Address,
 312                                                const MCDisassembler *Decoder) {
 313   return decodePCDBLOperand<32>(Inst, Imm, Address, true, Decoder);
 314 }
 315
 316 static DecodeStatus decodePC32DBLOperand(MCInst &Inst, uint64_t Imm,
 317                                          uint64_t Address,
 318                                          const MCDisassembler *Decoder) {
 319   return decodePCDBLOperand<32>(Inst, Imm, Address, false, Decoder);
 320 }
 321
 322 #include "SystemZGenDisassemblerTables.inc"
 323
 324 DecodeStatus SystemZDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
 325                                                  ArrayRef<uint8_t> Bytes,
 326                                                  uint64_t Address,
 327                                                  raw_ostream &CS) const {
 328   // Get the first two bytes of the instruction.
 329   Size = 0;
 330   if (Bytes.size() < 2)
 331     return MCDisassembler::Fail;
 332
 333   // The top 2 bits of the first byte specify the size.
 334   const uint8_t *Table;
 335   if (Bytes[0] < 0x40) {
 336     Size = 2;
 337     Table = DecoderTable16;
 338   } else if (Bytes[0] < 0xc0) {
 339     Size = 4;
 340     Table = DecoderTable32;
 341   } else {
 342     Size = 6;
 343     Table = DecoderTable48;
 344   }
 345
 346   // Read any remaining bytes.
 347   if (Bytes.size() < Size) {
 348     Size = Bytes.size();
 349     return MCDisassembler::Fail;
 350   }
 351
 352   // Construct the instruction.
 353   uint64_t Inst = 0;
 354   for (uint64_t I = 0; I < Size; ++I)
 355     Inst = (Inst << 8) | Bytes[I];
 356
 357   return decodeInstruction(Table, MI, Inst, Address, this, STI);
 358 }