xref: /freebsd/contrib/llvm-project/llvm/lib/Target/AArch64/Disassembler/AArch64Disassembler.cpp (revision 6be3386466ab79a84b48429ae66244f21526d3df)
1 //===- AArch64Disassembler.cpp - Disassembler for AArch64 -----------------===//
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 //
10 //===----------------------------------------------------------------------===//
11 
12 #include "AArch64Disassembler.h"
13 #include "AArch64ExternalSymbolizer.h"
14 #include "MCTargetDesc/AArch64AddressingModes.h"
15 #include "MCTargetDesc/AArch64MCTargetDesc.h"
16 #include "TargetInfo/AArch64TargetInfo.h"
17 #include "Utils/AArch64BaseInfo.h"
18 #include "llvm-c/Disassembler.h"
19 #include "llvm/MC/MCDisassembler/MCRelocationInfo.h"
20 #include "llvm/MC/MCFixedLenDisassembler.h"
21 #include "llvm/MC/MCInst.h"
22 #include "llvm/MC/MCRegisterInfo.h"
23 #include "llvm/MC/MCSubtargetInfo.h"
24 #include "llvm/Support/Compiler.h"
25 #include "llvm/Support/Debug.h"
26 #include "llvm/Support/ErrorHandling.h"
27 #include "llvm/Support/TargetRegistry.h"
28 #include <algorithm>
29 #include <memory>
30 
31 using namespace llvm;
32 
33 #define DEBUG_TYPE "aarch64-disassembler"
34 
35 // Pull DecodeStatus and its enum values into the global namespace.
36 using DecodeStatus = MCDisassembler::DecodeStatus;
37 
38 // Forward declare these because the autogenerated code will reference them.
39 // Definitions are further down.
40 static DecodeStatus DecodeFPR128RegisterClass(MCInst &Inst,
41                                               unsigned RegNo, uint64_t Address,
42                                               const void *Decoder);
43 static DecodeStatus DecodeFPR128_loRegisterClass(MCInst &Inst,
44                                                  unsigned RegNo,
45                                                  uint64_t Address,
46                                                  const void *Decoder);
47 static DecodeStatus DecodeFPR64RegisterClass(MCInst &Inst, unsigned RegNo,
48                                              uint64_t Address,
49                                              const void *Decoder);
50 static DecodeStatus DecodeFPR32RegisterClass(MCInst &Inst, unsigned RegNo,
51                                              uint64_t Address,
52                                              const void *Decoder);
53 static DecodeStatus DecodeFPR16RegisterClass(MCInst &Inst, unsigned RegNo,
54                                              uint64_t Address,
55                                              const void *Decoder);
56 static DecodeStatus DecodeFPR8RegisterClass(MCInst &Inst, unsigned RegNo,
57                                             uint64_t Address,
58                                             const void *Decoder);
59 static DecodeStatus DecodeGPR64commonRegisterClass(MCInst &Inst, unsigned RegNo,
60                                              uint64_t Address,
61                                              const void *Decoder);
62 static DecodeStatus DecodeGPR64RegisterClass(MCInst &Inst, unsigned RegNo,
63                                              uint64_t Address,
64                                              const void *Decoder);
65 static DecodeStatus DecodeGPR64spRegisterClass(MCInst &Inst,
66                                                unsigned RegNo, uint64_t Address,
67                                                const void *Decoder);
68 static DecodeStatus DecodeGPR32RegisterClass(MCInst &Inst, unsigned RegNo,
69                                              uint64_t Address,
70                                              const void *Decoder);
71 static DecodeStatus DecodeGPR32spRegisterClass(MCInst &Inst,
72                                                unsigned RegNo, uint64_t Address,
73                                                const void *Decoder);
74 static DecodeStatus DecodeQQRegisterClass(MCInst &Inst, unsigned RegNo,
75                                           uint64_t Address,
76                                           const void *Decoder);
77 static DecodeStatus DecodeQQQRegisterClass(MCInst &Inst, unsigned RegNo,
78                                            uint64_t Address,
79                                            const void *Decoder);
80 static DecodeStatus DecodeQQQQRegisterClass(MCInst &Inst, unsigned RegNo,
81                                             uint64_t Address,
82                                             const void *Decoder);
83 static DecodeStatus DecodeDDRegisterClass(MCInst &Inst, unsigned RegNo,
84                                           uint64_t Address,
85                                           const void *Decoder);
86 static DecodeStatus DecodeDDDRegisterClass(MCInst &Inst, unsigned RegNo,
87                                            uint64_t Address,
88                                            const void *Decoder);
89 static DecodeStatus DecodeDDDDRegisterClass(MCInst &Inst, unsigned RegNo,
90                                             uint64_t Address,
91                                             const void *Decoder);
92 static DecodeStatus DecodeZPRRegisterClass(MCInst &Inst, unsigned RegNo,
93                                            uint64_t Address,
94                                            const void *Decoder);
95 static DecodeStatus DecodeZPR_4bRegisterClass(MCInst &Inst, unsigned RegNo,
96                                               uint64_t Address,
97                                               const void *Decoder);
98 static DecodeStatus DecodeZPR_3bRegisterClass(MCInst &Inst, unsigned RegNo,
99                                               uint64_t Address,
100                                               const void *Decoder);
101 static DecodeStatus DecodeZPR2RegisterClass(MCInst &Inst, unsigned RegNo,
102                                             uint64_t Address,
103                                             const void *Decoder);
104 static DecodeStatus DecodeZPR3RegisterClass(MCInst &Inst, unsigned RegNo,
105                                             uint64_t Address,
106                                             const void *Decoder);
107 static DecodeStatus DecodeZPR4RegisterClass(MCInst &Inst, unsigned RegNo,
108                                             uint64_t Address,
109                                             const void *Decoder);
110 static DecodeStatus DecodePPRRegisterClass(MCInst &Inst, unsigned RegNo,
111                                            uint64_t Address,
112                                            const void *Decoder);
113 static DecodeStatus DecodePPR_3bRegisterClass(MCInst &Inst, unsigned RegNo,
114                                               uint64_t Address,
115                                               const void *Decoder);
116 
117 static DecodeStatus DecodeFixedPointScaleImm32(MCInst &Inst, unsigned Imm,
118                                                uint64_t Address,
119                                                const void *Decoder);
120 static DecodeStatus DecodeFixedPointScaleImm64(MCInst &Inst, unsigned Imm,
121                                                uint64_t Address,
122                                                const void *Decoder);
123 static DecodeStatus DecodePCRelLabel19(MCInst &Inst, unsigned Imm,
124                                        uint64_t Address, const void *Decoder);
125 static DecodeStatus DecodeMemExtend(MCInst &Inst, unsigned Imm,
126                                     uint64_t Address, const void *Decoder);
127 static DecodeStatus DecodeMRSSystemRegister(MCInst &Inst, unsigned Imm,
128                                             uint64_t Address, const void *Decoder);
129 static DecodeStatus DecodeMSRSystemRegister(MCInst &Inst, unsigned Imm,
130                                             uint64_t Address, const void *Decoder);
131 static DecodeStatus DecodeThreeAddrSRegInstruction(MCInst &Inst, uint32_t insn,
132                                                    uint64_t Address,
133                                                    const void *Decoder);
134 static DecodeStatus DecodeMoveImmInstruction(MCInst &Inst, uint32_t insn,
135                                              uint64_t Address,
136                                              const void *Decoder);
137 static DecodeStatus DecodeUnsignedLdStInstruction(MCInst &Inst, uint32_t insn,
138                                                   uint64_t Address,
139                                                   const void *Decoder);
140 static DecodeStatus DecodeSignedLdStInstruction(MCInst &Inst, uint32_t insn,
141                                                 uint64_t Address,
142                                                 const void *Decoder);
143 static DecodeStatus DecodeExclusiveLdStInstruction(MCInst &Inst, uint32_t insn,
144                                                    uint64_t Address,
145                                                    const void *Decoder);
146 static DecodeStatus DecodePairLdStInstruction(MCInst &Inst, uint32_t insn,
147                                               uint64_t Address,
148                                               const void *Decoder);
149 static DecodeStatus DecodeAuthLoadInstruction(MCInst &Inst, uint32_t insn,
150                                               uint64_t Address,
151                                               const void *Decoder);
152 static DecodeStatus DecodeAddSubERegInstruction(MCInst &Inst, uint32_t insn,
153                                                 uint64_t Address,
154                                                 const void *Decoder);
155 static DecodeStatus DecodeLogicalImmInstruction(MCInst &Inst, uint32_t insn,
156                                                 uint64_t Address,
157                                                 const void *Decoder);
158 static DecodeStatus DecodeModImmInstruction(MCInst &Inst, uint32_t insn,
159                                             uint64_t Address,
160                                             const void *Decoder);
161 static DecodeStatus DecodeModImmTiedInstruction(MCInst &Inst, uint32_t insn,
162                                                 uint64_t Address,
163                                                 const void *Decoder);
164 static DecodeStatus DecodeAdrInstruction(MCInst &Inst, uint32_t insn,
165                                          uint64_t Address, const void *Decoder);
166 static DecodeStatus DecodeAddSubImmShift(MCInst &Inst, uint32_t insn,
167                                          uint64_t Address, const void *Decoder);
168 static DecodeStatus DecodeUnconditionalBranch(MCInst &Inst, uint32_t insn,
169                                               uint64_t Address,
170                                               const void *Decoder);
171 static DecodeStatus DecodeSystemPStateInstruction(MCInst &Inst, uint32_t insn,
172                                                   uint64_t Address,
173                                                   const void *Decoder);
174 static DecodeStatus DecodeTestAndBranch(MCInst &Inst, uint32_t insn,
175                                         uint64_t Address, const void *Decoder);
176 
177 static DecodeStatus DecodeFMOVLaneInstruction(MCInst &Inst, unsigned Insn,
178                                               uint64_t Address,
179                                               const void *Decoder);
180 static DecodeStatus DecodeVecShiftR64Imm(MCInst &Inst, unsigned Imm,
181                                          uint64_t Addr, const void *Decoder);
182 static DecodeStatus DecodeVecShiftR64ImmNarrow(MCInst &Inst, unsigned Imm,
183                                                uint64_t Addr,
184                                                const void *Decoder);
185 static DecodeStatus DecodeVecShiftR32Imm(MCInst &Inst, unsigned Imm,
186                                          uint64_t Addr, const void *Decoder);
187 static DecodeStatus DecodeVecShiftR32ImmNarrow(MCInst &Inst, unsigned Imm,
188                                                uint64_t Addr,
189                                                const void *Decoder);
190 static DecodeStatus DecodeVecShiftR16Imm(MCInst &Inst, unsigned Imm,
191                                          uint64_t Addr, const void *Decoder);
192 static DecodeStatus DecodeVecShiftR16ImmNarrow(MCInst &Inst, unsigned Imm,
193                                                uint64_t Addr,
194                                                const void *Decoder);
195 static DecodeStatus DecodeVecShiftR8Imm(MCInst &Inst, unsigned Imm,
196                                         uint64_t Addr, const void *Decoder);
197 static DecodeStatus DecodeVecShiftL64Imm(MCInst &Inst, unsigned Imm,
198                                          uint64_t Addr, const void *Decoder);
199 static DecodeStatus DecodeVecShiftL32Imm(MCInst &Inst, unsigned Imm,
200                                          uint64_t Addr, const void *Decoder);
201 static DecodeStatus DecodeVecShiftL16Imm(MCInst &Inst, unsigned Imm,
202                                          uint64_t Addr, const void *Decoder);
203 static DecodeStatus DecodeVecShiftL8Imm(MCInst &Inst, unsigned Imm,
204                                         uint64_t Addr, const void *Decoder);
205 static DecodeStatus DecodeWSeqPairsClassRegisterClass(MCInst &Inst,
206                                                       unsigned RegNo,
207                                                       uint64_t Addr,
208                                                       const void *Decoder);
209 static DecodeStatus DecodeXSeqPairsClassRegisterClass(MCInst &Inst,
210                                                       unsigned RegNo,
211                                                       uint64_t Addr,
212                                                       const void *Decoder);
213 static DecodeStatus DecodeSVELogicalImmInstruction(llvm::MCInst &Inst,
214                                                    uint32_t insn,
215                                                    uint64_t Address,
216                                                    const void *Decoder);
217 template<int Bits>
218 static DecodeStatus DecodeSImm(llvm::MCInst &Inst, uint64_t Imm,
219                                uint64_t Address, const void *Decoder);
220 template <int ElementWidth>
221 static DecodeStatus DecodeImm8OptLsl(MCInst &Inst, unsigned Imm,
222                                      uint64_t Addr, const void *Decoder);
223 static DecodeStatus DecodeSVEIncDecImm(MCInst &Inst, unsigned Imm,
224                                        uint64_t Addr, const void *Decoder);
225 
226 static bool Check(DecodeStatus &Out, DecodeStatus In) {
227   switch (In) {
228     case MCDisassembler::Success:
229       // Out stays the same.
230       return true;
231     case MCDisassembler::SoftFail:
232       Out = In;
233       return true;
234     case MCDisassembler::Fail:
235       Out = In;
236       return false;
237   }
238   llvm_unreachable("Invalid DecodeStatus!");
239 }
240 
241 #include "AArch64GenDisassemblerTables.inc"
242 #include "AArch64GenInstrInfo.inc"
243 
244 #define Success MCDisassembler::Success
245 #define Fail MCDisassembler::Fail
246 #define SoftFail MCDisassembler::SoftFail
247 
248 static MCDisassembler *createAArch64Disassembler(const Target &T,
249                                                const MCSubtargetInfo &STI,
250                                                MCContext &Ctx) {
251   return new AArch64Disassembler(STI, Ctx);
252 }
253 
254 DecodeStatus AArch64Disassembler::getInstruction(MCInst &MI, uint64_t &Size,
255                                                  ArrayRef<uint8_t> Bytes,
256                                                  uint64_t Address,
257                                                  raw_ostream &CS) const {
258   CommentStream = &CS;
259 
260   Size = 0;
261   // We want to read exactly 4 bytes of data.
262   if (Bytes.size() < 4)
263     return Fail;
264   Size = 4;
265 
266   // Encoded as a small-endian 32-bit word in the stream.
267   uint32_t Insn =
268       (Bytes[3] << 24) | (Bytes[2] << 16) | (Bytes[1] << 8) | (Bytes[0] << 0);
269 
270   // Calling the auto-generated decoder function.
271   return decodeInstruction(DecoderTable32, MI, Insn, Address, this, STI);
272 }
273 
274 static MCSymbolizer *
275 createAArch64ExternalSymbolizer(const Triple &TT, LLVMOpInfoCallback GetOpInfo,
276                                 LLVMSymbolLookupCallback SymbolLookUp,
277                                 void *DisInfo, MCContext *Ctx,
278                                 std::unique_ptr<MCRelocationInfo> &&RelInfo) {
279   return new AArch64ExternalSymbolizer(*Ctx, std::move(RelInfo), GetOpInfo,
280                                        SymbolLookUp, DisInfo);
281 }
282 
283 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeAArch64Disassembler() {
284   TargetRegistry::RegisterMCDisassembler(getTheAArch64leTarget(),
285                                          createAArch64Disassembler);
286   TargetRegistry::RegisterMCDisassembler(getTheAArch64beTarget(),
287                                          createAArch64Disassembler);
288   TargetRegistry::RegisterMCSymbolizer(getTheAArch64leTarget(),
289                                        createAArch64ExternalSymbolizer);
290   TargetRegistry::RegisterMCSymbolizer(getTheAArch64beTarget(),
291                                        createAArch64ExternalSymbolizer);
292   TargetRegistry::RegisterMCDisassembler(getTheAArch64_32Target(),
293                                          createAArch64Disassembler);
294   TargetRegistry::RegisterMCSymbolizer(getTheAArch64_32Target(),
295                                        createAArch64ExternalSymbolizer);
296 
297   TargetRegistry::RegisterMCDisassembler(getTheARM64Target(),
298                                          createAArch64Disassembler);
299   TargetRegistry::RegisterMCSymbolizer(getTheARM64Target(),
300                                        createAArch64ExternalSymbolizer);
301   TargetRegistry::RegisterMCDisassembler(getTheARM64_32Target(),
302                                          createAArch64Disassembler);
303   TargetRegistry::RegisterMCSymbolizer(getTheARM64_32Target(),
304                                        createAArch64ExternalSymbolizer);
305 }
306 
307 static const unsigned FPR128DecoderTable[] = {
308     AArch64::Q0,  AArch64::Q1,  AArch64::Q2,  AArch64::Q3,  AArch64::Q4,
309     AArch64::Q5,  AArch64::Q6,  AArch64::Q7,  AArch64::Q8,  AArch64::Q9,
310     AArch64::Q10, AArch64::Q11, AArch64::Q12, AArch64::Q13, AArch64::Q14,
311     AArch64::Q15, AArch64::Q16, AArch64::Q17, AArch64::Q18, AArch64::Q19,
312     AArch64::Q20, AArch64::Q21, AArch64::Q22, AArch64::Q23, AArch64::Q24,
313     AArch64::Q25, AArch64::Q26, AArch64::Q27, AArch64::Q28, AArch64::Q29,
314     AArch64::Q30, AArch64::Q31
315 };
316 
317 static DecodeStatus DecodeFPR128RegisterClass(MCInst &Inst, unsigned RegNo,
318                                               uint64_t Addr,
319                                               const void *Decoder) {
320   if (RegNo > 31)
321     return Fail;
322 
323   unsigned Register = FPR128DecoderTable[RegNo];
324   Inst.addOperand(MCOperand::createReg(Register));
325   return Success;
326 }
327 
328 static DecodeStatus DecodeFPR128_loRegisterClass(MCInst &Inst, unsigned RegNo,
329                                                  uint64_t Addr,
330                                                  const void *Decoder) {
331   if (RegNo > 15)
332     return Fail;
333   return DecodeFPR128RegisterClass(Inst, RegNo, Addr, Decoder);
334 }
335 
336 static const unsigned FPR64DecoderTable[] = {
337     AArch64::D0,  AArch64::D1,  AArch64::D2,  AArch64::D3,  AArch64::D4,
338     AArch64::D5,  AArch64::D6,  AArch64::D7,  AArch64::D8,  AArch64::D9,
339     AArch64::D10, AArch64::D11, AArch64::D12, AArch64::D13, AArch64::D14,
340     AArch64::D15, AArch64::D16, AArch64::D17, AArch64::D18, AArch64::D19,
341     AArch64::D20, AArch64::D21, AArch64::D22, AArch64::D23, AArch64::D24,
342     AArch64::D25, AArch64::D26, AArch64::D27, AArch64::D28, AArch64::D29,
343     AArch64::D30, AArch64::D31
344 };
345 
346 static DecodeStatus DecodeFPR64RegisterClass(MCInst &Inst, unsigned RegNo,
347                                              uint64_t Addr,
348                                              const void *Decoder) {
349   if (RegNo > 31)
350     return Fail;
351 
352   unsigned Register = FPR64DecoderTable[RegNo];
353   Inst.addOperand(MCOperand::createReg(Register));
354   return Success;
355 }
356 
357 static const unsigned FPR32DecoderTable[] = {
358     AArch64::S0,  AArch64::S1,  AArch64::S2,  AArch64::S3,  AArch64::S4,
359     AArch64::S5,  AArch64::S6,  AArch64::S7,  AArch64::S8,  AArch64::S9,
360     AArch64::S10, AArch64::S11, AArch64::S12, AArch64::S13, AArch64::S14,
361     AArch64::S15, AArch64::S16, AArch64::S17, AArch64::S18, AArch64::S19,
362     AArch64::S20, AArch64::S21, AArch64::S22, AArch64::S23, AArch64::S24,
363     AArch64::S25, AArch64::S26, AArch64::S27, AArch64::S28, AArch64::S29,
364     AArch64::S30, AArch64::S31
365 };
366 
367 static DecodeStatus DecodeFPR32RegisterClass(MCInst &Inst, unsigned RegNo,
368                                              uint64_t Addr,
369                                              const void *Decoder) {
370   if (RegNo > 31)
371     return Fail;
372 
373   unsigned Register = FPR32DecoderTable[RegNo];
374   Inst.addOperand(MCOperand::createReg(Register));
375   return Success;
376 }
377 
378 static const unsigned FPR16DecoderTable[] = {
379     AArch64::H0,  AArch64::H1,  AArch64::H2,  AArch64::H3,  AArch64::H4,
380     AArch64::H5,  AArch64::H6,  AArch64::H7,  AArch64::H8,  AArch64::H9,
381     AArch64::H10, AArch64::H11, AArch64::H12, AArch64::H13, AArch64::H14,
382     AArch64::H15, AArch64::H16, AArch64::H17, AArch64::H18, AArch64::H19,
383     AArch64::H20, AArch64::H21, AArch64::H22, AArch64::H23, AArch64::H24,
384     AArch64::H25, AArch64::H26, AArch64::H27, AArch64::H28, AArch64::H29,
385     AArch64::H30, AArch64::H31
386 };
387 
388 static DecodeStatus DecodeFPR16RegisterClass(MCInst &Inst, unsigned RegNo,
389                                              uint64_t Addr,
390                                              const void *Decoder) {
391   if (RegNo > 31)
392     return Fail;
393 
394   unsigned Register = FPR16DecoderTable[RegNo];
395   Inst.addOperand(MCOperand::createReg(Register));
396   return Success;
397 }
398 
399 static const unsigned FPR8DecoderTable[] = {
400     AArch64::B0,  AArch64::B1,  AArch64::B2,  AArch64::B3,  AArch64::B4,
401     AArch64::B5,  AArch64::B6,  AArch64::B7,  AArch64::B8,  AArch64::B9,
402     AArch64::B10, AArch64::B11, AArch64::B12, AArch64::B13, AArch64::B14,
403     AArch64::B15, AArch64::B16, AArch64::B17, AArch64::B18, AArch64::B19,
404     AArch64::B20, AArch64::B21, AArch64::B22, AArch64::B23, AArch64::B24,
405     AArch64::B25, AArch64::B26, AArch64::B27, AArch64::B28, AArch64::B29,
406     AArch64::B30, AArch64::B31
407 };
408 
409 static DecodeStatus DecodeFPR8RegisterClass(MCInst &Inst, unsigned RegNo,
410                                             uint64_t Addr,
411                                             const void *Decoder) {
412   if (RegNo > 31)
413     return Fail;
414 
415   unsigned Register = FPR8DecoderTable[RegNo];
416   Inst.addOperand(MCOperand::createReg(Register));
417   return Success;
418 }
419 
420 static const unsigned GPR64DecoderTable[] = {
421     AArch64::X0,  AArch64::X1,  AArch64::X2,  AArch64::X3,  AArch64::X4,
422     AArch64::X5,  AArch64::X6,  AArch64::X7,  AArch64::X8,  AArch64::X9,
423     AArch64::X10, AArch64::X11, AArch64::X12, AArch64::X13, AArch64::X14,
424     AArch64::X15, AArch64::X16, AArch64::X17, AArch64::X18, AArch64::X19,
425     AArch64::X20, AArch64::X21, AArch64::X22, AArch64::X23, AArch64::X24,
426     AArch64::X25, AArch64::X26, AArch64::X27, AArch64::X28, AArch64::FP,
427     AArch64::LR,  AArch64::XZR
428 };
429 
430 static DecodeStatus DecodeGPR64commonRegisterClass(MCInst &Inst, unsigned RegNo,
431                                                    uint64_t Addr,
432                                                    const void *Decoder) {
433   if (RegNo > 30)
434     return Fail;
435 
436   unsigned Register = GPR64DecoderTable[RegNo];
437   Inst.addOperand(MCOperand::createReg(Register));
438   return Success;
439 }
440 
441 static DecodeStatus DecodeGPR64RegisterClass(MCInst &Inst, unsigned RegNo,
442                                              uint64_t Addr,
443                                              const void *Decoder) {
444   if (RegNo > 31)
445     return Fail;
446 
447   unsigned Register = GPR64DecoderTable[RegNo];
448   Inst.addOperand(MCOperand::createReg(Register));
449   return Success;
450 }
451 
452 static DecodeStatus DecodeGPR64spRegisterClass(MCInst &Inst, unsigned RegNo,
453                                                uint64_t Addr,
454                                                const void *Decoder) {
455   if (RegNo > 31)
456     return Fail;
457   unsigned Register = GPR64DecoderTable[RegNo];
458   if (Register == AArch64::XZR)
459     Register = AArch64::SP;
460   Inst.addOperand(MCOperand::createReg(Register));
461   return Success;
462 }
463 
464 static const unsigned GPR32DecoderTable[] = {
465     AArch64::W0,  AArch64::W1,  AArch64::W2,  AArch64::W3,  AArch64::W4,
466     AArch64::W5,  AArch64::W6,  AArch64::W7,  AArch64::W8,  AArch64::W9,
467     AArch64::W10, AArch64::W11, AArch64::W12, AArch64::W13, AArch64::W14,
468     AArch64::W15, AArch64::W16, AArch64::W17, AArch64::W18, AArch64::W19,
469     AArch64::W20, AArch64::W21, AArch64::W22, AArch64::W23, AArch64::W24,
470     AArch64::W25, AArch64::W26, AArch64::W27, AArch64::W28, AArch64::W29,
471     AArch64::W30, AArch64::WZR
472 };
473 
474 static DecodeStatus DecodeGPR32RegisterClass(MCInst &Inst, unsigned RegNo,
475                                              uint64_t Addr,
476                                              const void *Decoder) {
477   if (RegNo > 31)
478     return Fail;
479 
480   unsigned Register = GPR32DecoderTable[RegNo];
481   Inst.addOperand(MCOperand::createReg(Register));
482   return Success;
483 }
484 
485 static DecodeStatus DecodeGPR32spRegisterClass(MCInst &Inst, unsigned RegNo,
486                                                uint64_t Addr,
487                                                const void *Decoder) {
488   if (RegNo > 31)
489     return Fail;
490 
491   unsigned Register = GPR32DecoderTable[RegNo];
492   if (Register == AArch64::WZR)
493     Register = AArch64::WSP;
494   Inst.addOperand(MCOperand::createReg(Register));
495   return Success;
496 }
497 static const unsigned ZPRDecoderTable[] = {
498     AArch64::Z0,  AArch64::Z1,  AArch64::Z2,  AArch64::Z3,
499     AArch64::Z4,  AArch64::Z5,  AArch64::Z6,  AArch64::Z7,
500     AArch64::Z8,  AArch64::Z9,  AArch64::Z10, AArch64::Z11,
501     AArch64::Z12, AArch64::Z13, AArch64::Z14, AArch64::Z15,
502     AArch64::Z16, AArch64::Z17, AArch64::Z18, AArch64::Z19,
503     AArch64::Z20, AArch64::Z21, AArch64::Z22, AArch64::Z23,
504     AArch64::Z24, AArch64::Z25, AArch64::Z26, AArch64::Z27,
505     AArch64::Z28, AArch64::Z29, AArch64::Z30, AArch64::Z31
506 };
507 
508 static DecodeStatus DecodeZPRRegisterClass(MCInst &Inst, unsigned RegNo,
509                                            uint64_t Address,
510                                            const void* Decoder) {
511   if (RegNo > 31)
512     return Fail;
513 
514   unsigned Register = ZPRDecoderTable[RegNo];
515   Inst.addOperand(MCOperand::createReg(Register));
516   return Success;
517 }
518 
519 static DecodeStatus DecodeZPR_4bRegisterClass(MCInst &Inst, unsigned RegNo,
520                                               uint64_t Address,
521                                               const void *Decoder) {
522   if (RegNo > 15)
523     return Fail;
524   return DecodeZPRRegisterClass(Inst, RegNo, Address, Decoder);
525 }
526 
527 static DecodeStatus DecodeZPR_3bRegisterClass(MCInst &Inst, unsigned RegNo,
528                                               uint64_t Address,
529                                               const void *Decoder) {
530   if (RegNo > 7)
531     return Fail;
532   return DecodeZPRRegisterClass(Inst, RegNo, Address, Decoder);
533 }
534 
535 static const unsigned ZZDecoderTable[] = {
536   AArch64::Z0_Z1,   AArch64::Z1_Z2,   AArch64::Z2_Z3,   AArch64::Z3_Z4,
537   AArch64::Z4_Z5,   AArch64::Z5_Z6,   AArch64::Z6_Z7,   AArch64::Z7_Z8,
538   AArch64::Z8_Z9,   AArch64::Z9_Z10,  AArch64::Z10_Z11, AArch64::Z11_Z12,
539   AArch64::Z12_Z13, AArch64::Z13_Z14, AArch64::Z14_Z15, AArch64::Z15_Z16,
540   AArch64::Z16_Z17, AArch64::Z17_Z18, AArch64::Z18_Z19, AArch64::Z19_Z20,
541   AArch64::Z20_Z21, AArch64::Z21_Z22, AArch64::Z22_Z23, AArch64::Z23_Z24,
542   AArch64::Z24_Z25, AArch64::Z25_Z26, AArch64::Z26_Z27, AArch64::Z27_Z28,
543   AArch64::Z28_Z29, AArch64::Z29_Z30, AArch64::Z30_Z31, AArch64::Z31_Z0
544 };
545 
546 static DecodeStatus DecodeZPR2RegisterClass(MCInst &Inst, unsigned RegNo,
547                                             uint64_t Address,
548                                             const void* Decoder) {
549   if (RegNo > 31)
550     return Fail;
551   unsigned Register = ZZDecoderTable[RegNo];
552   Inst.addOperand(MCOperand::createReg(Register));
553   return Success;
554 }
555 
556 static const unsigned ZZZDecoderTable[] = {
557   AArch64::Z0_Z1_Z2,    AArch64::Z1_Z2_Z3,    AArch64::Z2_Z3_Z4,
558   AArch64::Z3_Z4_Z5,    AArch64::Z4_Z5_Z6,    AArch64::Z5_Z6_Z7,
559   AArch64::Z6_Z7_Z8,    AArch64::Z7_Z8_Z9,    AArch64::Z8_Z9_Z10,
560   AArch64::Z9_Z10_Z11,  AArch64::Z10_Z11_Z12, AArch64::Z11_Z12_Z13,
561   AArch64::Z12_Z13_Z14, AArch64::Z13_Z14_Z15, AArch64::Z14_Z15_Z16,
562   AArch64::Z15_Z16_Z17, AArch64::Z16_Z17_Z18, AArch64::Z17_Z18_Z19,
563   AArch64::Z18_Z19_Z20, AArch64::Z19_Z20_Z21, AArch64::Z20_Z21_Z22,
564   AArch64::Z21_Z22_Z23, AArch64::Z22_Z23_Z24, AArch64::Z23_Z24_Z25,
565   AArch64::Z24_Z25_Z26, AArch64::Z25_Z26_Z27, AArch64::Z26_Z27_Z28,
566   AArch64::Z27_Z28_Z29, AArch64::Z28_Z29_Z30, AArch64::Z29_Z30_Z31,
567   AArch64::Z30_Z31_Z0,  AArch64::Z31_Z0_Z1
568 };
569 
570 static DecodeStatus DecodeZPR3RegisterClass(MCInst &Inst, unsigned RegNo,
571                                             uint64_t Address,
572                                             const void* Decoder) {
573   if (RegNo > 31)
574     return Fail;
575   unsigned Register = ZZZDecoderTable[RegNo];
576   Inst.addOperand(MCOperand::createReg(Register));
577   return Success;
578 }
579 
580 static const unsigned ZZZZDecoderTable[] = {
581   AArch64::Z0_Z1_Z2_Z3,     AArch64::Z1_Z2_Z3_Z4,     AArch64::Z2_Z3_Z4_Z5,
582   AArch64::Z3_Z4_Z5_Z6,     AArch64::Z4_Z5_Z6_Z7,     AArch64::Z5_Z6_Z7_Z8,
583   AArch64::Z6_Z7_Z8_Z9,     AArch64::Z7_Z8_Z9_Z10,    AArch64::Z8_Z9_Z10_Z11,
584   AArch64::Z9_Z10_Z11_Z12,  AArch64::Z10_Z11_Z12_Z13, AArch64::Z11_Z12_Z13_Z14,
585   AArch64::Z12_Z13_Z14_Z15, AArch64::Z13_Z14_Z15_Z16, AArch64::Z14_Z15_Z16_Z17,
586   AArch64::Z15_Z16_Z17_Z18, AArch64::Z16_Z17_Z18_Z19, AArch64::Z17_Z18_Z19_Z20,
587   AArch64::Z18_Z19_Z20_Z21, AArch64::Z19_Z20_Z21_Z22, AArch64::Z20_Z21_Z22_Z23,
588   AArch64::Z21_Z22_Z23_Z24, AArch64::Z22_Z23_Z24_Z25, AArch64::Z23_Z24_Z25_Z26,
589   AArch64::Z24_Z25_Z26_Z27, AArch64::Z25_Z26_Z27_Z28, AArch64::Z26_Z27_Z28_Z29,
590   AArch64::Z27_Z28_Z29_Z30, AArch64::Z28_Z29_Z30_Z31, AArch64::Z29_Z30_Z31_Z0,
591   AArch64::Z30_Z31_Z0_Z1,   AArch64::Z31_Z0_Z1_Z2
592 };
593 
594 static DecodeStatus DecodeZPR4RegisterClass(MCInst &Inst, unsigned RegNo,
595                                             uint64_t Address,
596                                             const void* Decoder) {
597   if (RegNo > 31)
598     return Fail;
599   unsigned Register = ZZZZDecoderTable[RegNo];
600   Inst.addOperand(MCOperand::createReg(Register));
601   return Success;
602 }
603 
604 static const unsigned PPRDecoderTable[] = {
605   AArch64::P0,  AArch64::P1,  AArch64::P2,  AArch64::P3,
606   AArch64::P4,  AArch64::P5,  AArch64::P6,  AArch64::P7,
607   AArch64::P8,  AArch64::P9,  AArch64::P10, AArch64::P11,
608   AArch64::P12, AArch64::P13, AArch64::P14, AArch64::P15
609 };
610 
611 static DecodeStatus DecodePPRRegisterClass(MCInst &Inst, unsigned RegNo,
612                                            uint64_t Addr, const void *Decoder) {
613   if (RegNo > 15)
614     return Fail;
615 
616   unsigned Register = PPRDecoderTable[RegNo];
617   Inst.addOperand(MCOperand::createReg(Register));
618   return Success;
619 }
620 
621 static DecodeStatus DecodePPR_3bRegisterClass(MCInst &Inst, unsigned RegNo,
622                                               uint64_t Addr,
623                                               const void* Decoder) {
624   if (RegNo > 7)
625     return Fail;
626 
627   // Just reuse the PPR decode table
628   return DecodePPRRegisterClass(Inst, RegNo, Addr, Decoder);
629 }
630 
631 static const unsigned VectorDecoderTable[] = {
632     AArch64::Q0,  AArch64::Q1,  AArch64::Q2,  AArch64::Q3,  AArch64::Q4,
633     AArch64::Q5,  AArch64::Q6,  AArch64::Q7,  AArch64::Q8,  AArch64::Q9,
634     AArch64::Q10, AArch64::Q11, AArch64::Q12, AArch64::Q13, AArch64::Q14,
635     AArch64::Q15, AArch64::Q16, AArch64::Q17, AArch64::Q18, AArch64::Q19,
636     AArch64::Q20, AArch64::Q21, AArch64::Q22, AArch64::Q23, AArch64::Q24,
637     AArch64::Q25, AArch64::Q26, AArch64::Q27, AArch64::Q28, AArch64::Q29,
638     AArch64::Q30, AArch64::Q31
639 };
640 
641 static DecodeStatus DecodeVectorRegisterClass(MCInst &Inst, unsigned RegNo,
642                                               uint64_t Addr,
643                                               const void *Decoder) {
644   if (RegNo > 31)
645     return Fail;
646 
647   unsigned Register = VectorDecoderTable[RegNo];
648   Inst.addOperand(MCOperand::createReg(Register));
649   return Success;
650 }
651 
652 static const unsigned QQDecoderTable[] = {
653   AArch64::Q0_Q1,   AArch64::Q1_Q2,   AArch64::Q2_Q3,   AArch64::Q3_Q4,
654   AArch64::Q4_Q5,   AArch64::Q5_Q6,   AArch64::Q6_Q7,   AArch64::Q7_Q8,
655   AArch64::Q8_Q9,   AArch64::Q9_Q10,  AArch64::Q10_Q11, AArch64::Q11_Q12,
656   AArch64::Q12_Q13, AArch64::Q13_Q14, AArch64::Q14_Q15, AArch64::Q15_Q16,
657   AArch64::Q16_Q17, AArch64::Q17_Q18, AArch64::Q18_Q19, AArch64::Q19_Q20,
658   AArch64::Q20_Q21, AArch64::Q21_Q22, AArch64::Q22_Q23, AArch64::Q23_Q24,
659   AArch64::Q24_Q25, AArch64::Q25_Q26, AArch64::Q26_Q27, AArch64::Q27_Q28,
660   AArch64::Q28_Q29, AArch64::Q29_Q30, AArch64::Q30_Q31, AArch64::Q31_Q0
661 };
662 
663 static DecodeStatus DecodeQQRegisterClass(MCInst &Inst, unsigned RegNo,
664                                           uint64_t Addr, const void *Decoder) {
665   if (RegNo > 31)
666     return Fail;
667   unsigned Register = QQDecoderTable[RegNo];
668   Inst.addOperand(MCOperand::createReg(Register));
669   return Success;
670 }
671 
672 static const unsigned QQQDecoderTable[] = {
673   AArch64::Q0_Q1_Q2,    AArch64::Q1_Q2_Q3,    AArch64::Q2_Q3_Q4,
674   AArch64::Q3_Q4_Q5,    AArch64::Q4_Q5_Q6,    AArch64::Q5_Q6_Q7,
675   AArch64::Q6_Q7_Q8,    AArch64::Q7_Q8_Q9,    AArch64::Q8_Q9_Q10,
676   AArch64::Q9_Q10_Q11,  AArch64::Q10_Q11_Q12, AArch64::Q11_Q12_Q13,
677   AArch64::Q12_Q13_Q14, AArch64::Q13_Q14_Q15, AArch64::Q14_Q15_Q16,
678   AArch64::Q15_Q16_Q17, AArch64::Q16_Q17_Q18, AArch64::Q17_Q18_Q19,
679   AArch64::Q18_Q19_Q20, AArch64::Q19_Q20_Q21, AArch64::Q20_Q21_Q22,
680   AArch64::Q21_Q22_Q23, AArch64::Q22_Q23_Q24, AArch64::Q23_Q24_Q25,
681   AArch64::Q24_Q25_Q26, AArch64::Q25_Q26_Q27, AArch64::Q26_Q27_Q28,
682   AArch64::Q27_Q28_Q29, AArch64::Q28_Q29_Q30, AArch64::Q29_Q30_Q31,
683   AArch64::Q30_Q31_Q0,  AArch64::Q31_Q0_Q1
684 };
685 
686 static DecodeStatus DecodeQQQRegisterClass(MCInst &Inst, unsigned RegNo,
687                                            uint64_t Addr, const void *Decoder) {
688   if (RegNo > 31)
689     return Fail;
690   unsigned Register = QQQDecoderTable[RegNo];
691   Inst.addOperand(MCOperand::createReg(Register));
692   return Success;
693 }
694 
695 static const unsigned QQQQDecoderTable[] = {
696   AArch64::Q0_Q1_Q2_Q3,     AArch64::Q1_Q2_Q3_Q4,     AArch64::Q2_Q3_Q4_Q5,
697   AArch64::Q3_Q4_Q5_Q6,     AArch64::Q4_Q5_Q6_Q7,     AArch64::Q5_Q6_Q7_Q8,
698   AArch64::Q6_Q7_Q8_Q9,     AArch64::Q7_Q8_Q9_Q10,    AArch64::Q8_Q9_Q10_Q11,
699   AArch64::Q9_Q10_Q11_Q12,  AArch64::Q10_Q11_Q12_Q13, AArch64::Q11_Q12_Q13_Q14,
700   AArch64::Q12_Q13_Q14_Q15, AArch64::Q13_Q14_Q15_Q16, AArch64::Q14_Q15_Q16_Q17,
701   AArch64::Q15_Q16_Q17_Q18, AArch64::Q16_Q17_Q18_Q19, AArch64::Q17_Q18_Q19_Q20,
702   AArch64::Q18_Q19_Q20_Q21, AArch64::Q19_Q20_Q21_Q22, AArch64::Q20_Q21_Q22_Q23,
703   AArch64::Q21_Q22_Q23_Q24, AArch64::Q22_Q23_Q24_Q25, AArch64::Q23_Q24_Q25_Q26,
704   AArch64::Q24_Q25_Q26_Q27, AArch64::Q25_Q26_Q27_Q28, AArch64::Q26_Q27_Q28_Q29,
705   AArch64::Q27_Q28_Q29_Q30, AArch64::Q28_Q29_Q30_Q31, AArch64::Q29_Q30_Q31_Q0,
706   AArch64::Q30_Q31_Q0_Q1,   AArch64::Q31_Q0_Q1_Q2
707 };
708 
709 static DecodeStatus DecodeQQQQRegisterClass(MCInst &Inst, unsigned RegNo,
710                                             uint64_t Addr,
711                                             const void *Decoder) {
712   if (RegNo > 31)
713     return Fail;
714   unsigned Register = QQQQDecoderTable[RegNo];
715   Inst.addOperand(MCOperand::createReg(Register));
716   return Success;
717 }
718 
719 static const unsigned DDDecoderTable[] = {
720   AArch64::D0_D1,   AArch64::D1_D2,   AArch64::D2_D3,   AArch64::D3_D4,
721   AArch64::D4_D5,   AArch64::D5_D6,   AArch64::D6_D7,   AArch64::D7_D8,
722   AArch64::D8_D9,   AArch64::D9_D10,  AArch64::D10_D11, AArch64::D11_D12,
723   AArch64::D12_D13, AArch64::D13_D14, AArch64::D14_D15, AArch64::D15_D16,
724   AArch64::D16_D17, AArch64::D17_D18, AArch64::D18_D19, AArch64::D19_D20,
725   AArch64::D20_D21, AArch64::D21_D22, AArch64::D22_D23, AArch64::D23_D24,
726   AArch64::D24_D25, AArch64::D25_D26, AArch64::D26_D27, AArch64::D27_D28,
727   AArch64::D28_D29, AArch64::D29_D30, AArch64::D30_D31, AArch64::D31_D0
728 };
729 
730 static DecodeStatus DecodeDDRegisterClass(MCInst &Inst, unsigned RegNo,
731                                           uint64_t Addr, const void *Decoder) {
732   if (RegNo > 31)
733     return Fail;
734   unsigned Register = DDDecoderTable[RegNo];
735   Inst.addOperand(MCOperand::createReg(Register));
736   return Success;
737 }
738 
739 static const unsigned DDDDecoderTable[] = {
740   AArch64::D0_D1_D2,    AArch64::D1_D2_D3,    AArch64::D2_D3_D4,
741   AArch64::D3_D4_D5,    AArch64::D4_D5_D6,    AArch64::D5_D6_D7,
742   AArch64::D6_D7_D8,    AArch64::D7_D8_D9,    AArch64::D8_D9_D10,
743   AArch64::D9_D10_D11,  AArch64::D10_D11_D12, AArch64::D11_D12_D13,
744   AArch64::D12_D13_D14, AArch64::D13_D14_D15, AArch64::D14_D15_D16,
745   AArch64::D15_D16_D17, AArch64::D16_D17_D18, AArch64::D17_D18_D19,
746   AArch64::D18_D19_D20, AArch64::D19_D20_D21, AArch64::D20_D21_D22,
747   AArch64::D21_D22_D23, AArch64::D22_D23_D24, AArch64::D23_D24_D25,
748   AArch64::D24_D25_D26, AArch64::D25_D26_D27, AArch64::D26_D27_D28,
749   AArch64::D27_D28_D29, AArch64::D28_D29_D30, AArch64::D29_D30_D31,
750   AArch64::D30_D31_D0,  AArch64::D31_D0_D1
751 };
752 
753 static DecodeStatus DecodeDDDRegisterClass(MCInst &Inst, unsigned RegNo,
754                                            uint64_t Addr, const void *Decoder) {
755   if (RegNo > 31)
756     return Fail;
757   unsigned Register = DDDDecoderTable[RegNo];
758   Inst.addOperand(MCOperand::createReg(Register));
759   return Success;
760 }
761 
762 static const unsigned DDDDDecoderTable[] = {
763   AArch64::D0_D1_D2_D3,     AArch64::D1_D2_D3_D4,     AArch64::D2_D3_D4_D5,
764   AArch64::D3_D4_D5_D6,     AArch64::D4_D5_D6_D7,     AArch64::D5_D6_D7_D8,
765   AArch64::D6_D7_D8_D9,     AArch64::D7_D8_D9_D10,    AArch64::D8_D9_D10_D11,
766   AArch64::D9_D10_D11_D12,  AArch64::D10_D11_D12_D13, AArch64::D11_D12_D13_D14,
767   AArch64::D12_D13_D14_D15, AArch64::D13_D14_D15_D16, AArch64::D14_D15_D16_D17,
768   AArch64::D15_D16_D17_D18, AArch64::D16_D17_D18_D19, AArch64::D17_D18_D19_D20,
769   AArch64::D18_D19_D20_D21, AArch64::D19_D20_D21_D22, AArch64::D20_D21_D22_D23,
770   AArch64::D21_D22_D23_D24, AArch64::D22_D23_D24_D25, AArch64::D23_D24_D25_D26,
771   AArch64::D24_D25_D26_D27, AArch64::D25_D26_D27_D28, AArch64::D26_D27_D28_D29,
772   AArch64::D27_D28_D29_D30, AArch64::D28_D29_D30_D31, AArch64::D29_D30_D31_D0,
773   AArch64::D30_D31_D0_D1,   AArch64::D31_D0_D1_D2
774 };
775 
776 static DecodeStatus DecodeDDDDRegisterClass(MCInst &Inst, unsigned RegNo,
777                                             uint64_t Addr,
778                                             const void *Decoder) {
779   if (RegNo > 31)
780     return Fail;
781   unsigned Register = DDDDDecoderTable[RegNo];
782   Inst.addOperand(MCOperand::createReg(Register));
783   return Success;
784 }
785 
786 static DecodeStatus DecodeFixedPointScaleImm32(MCInst &Inst, unsigned Imm,
787                                                uint64_t Addr,
788                                                const void *Decoder) {
789   // scale{5} is asserted as 1 in tblgen.
790   Imm |= 0x20;
791   Inst.addOperand(MCOperand::createImm(64 - Imm));
792   return Success;
793 }
794 
795 static DecodeStatus DecodeFixedPointScaleImm64(MCInst &Inst, unsigned Imm,
796                                                uint64_t Addr,
797                                                const void *Decoder) {
798   Inst.addOperand(MCOperand::createImm(64 - Imm));
799   return Success;
800 }
801 
802 static DecodeStatus DecodePCRelLabel19(MCInst &Inst, unsigned Imm,
803                                        uint64_t Addr, const void *Decoder) {
804   int64_t ImmVal = Imm;
805   const AArch64Disassembler *Dis =
806       static_cast<const AArch64Disassembler *>(Decoder);
807 
808   // Sign-extend 19-bit immediate.
809   if (ImmVal & (1 << (19 - 1)))
810     ImmVal |= ~((1LL << 19) - 1);
811 
812   if (!Dis->tryAddingSymbolicOperand(Inst, ImmVal *  4, Addr,
813                                      Inst.getOpcode() != AArch64::LDRXl, 0, 4))
814     Inst.addOperand(MCOperand::createImm(ImmVal));
815   return Success;
816 }
817 
818 static DecodeStatus DecodeMemExtend(MCInst &Inst, unsigned Imm,
819                                     uint64_t Address, const void *Decoder) {
820   Inst.addOperand(MCOperand::createImm((Imm  >> 1) & 1));
821   Inst.addOperand(MCOperand::createImm(Imm & 1));
822   return Success;
823 }
824 
825 static DecodeStatus DecodeMRSSystemRegister(MCInst &Inst, unsigned Imm,
826                                             uint64_t Address,
827                                             const void *Decoder) {
828   Inst.addOperand(MCOperand::createImm(Imm));
829 
830   // Every system register in the encoding space is valid with the syntax
831   // S<op0>_<op1>_<Cn>_<Cm>_<op2>, so decoding system registers always succeeds.
832   return Success;
833 }
834 
835 static DecodeStatus DecodeMSRSystemRegister(MCInst &Inst, unsigned Imm,
836                                             uint64_t Address,
837                                             const void *Decoder) {
838   Inst.addOperand(MCOperand::createImm(Imm));
839 
840   return Success;
841 }
842 
843 static DecodeStatus DecodeFMOVLaneInstruction(MCInst &Inst, unsigned Insn,
844                                               uint64_t Address,
845                                               const void *Decoder) {
846   // This decoder exists to add the dummy Lane operand to the MCInst, which must
847   // be 1 in assembly but has no other real manifestation.
848   unsigned Rd = fieldFromInstruction(Insn, 0, 5);
849   unsigned Rn = fieldFromInstruction(Insn, 5, 5);
850   unsigned IsToVec = fieldFromInstruction(Insn, 16, 1);
851 
852   if (IsToVec) {
853     DecodeFPR128RegisterClass(Inst, Rd, Address, Decoder);
854     DecodeGPR64RegisterClass(Inst, Rn, Address, Decoder);
855   } else {
856     DecodeGPR64RegisterClass(Inst, Rd, Address, Decoder);
857     DecodeFPR128RegisterClass(Inst, Rn, Address, Decoder);
858   }
859 
860   // Add the lane
861   Inst.addOperand(MCOperand::createImm(1));
862 
863   return Success;
864 }
865 
866 static DecodeStatus DecodeVecShiftRImm(MCInst &Inst, unsigned Imm,
867                                        unsigned Add) {
868   Inst.addOperand(MCOperand::createImm(Add - Imm));
869   return Success;
870 }
871 
872 static DecodeStatus DecodeVecShiftLImm(MCInst &Inst, unsigned Imm,
873                                        unsigned Add) {
874   Inst.addOperand(MCOperand::createImm((Imm + Add) & (Add - 1)));
875   return Success;
876 }
877 
878 static DecodeStatus DecodeVecShiftR64Imm(MCInst &Inst, unsigned Imm,
879                                          uint64_t Addr, const void *Decoder) {
880   return DecodeVecShiftRImm(Inst, Imm, 64);
881 }
882 
883 static DecodeStatus DecodeVecShiftR64ImmNarrow(MCInst &Inst, unsigned Imm,
884                                                uint64_t Addr,
885                                                const void *Decoder) {
886   return DecodeVecShiftRImm(Inst, Imm | 0x20, 64);
887 }
888 
889 static DecodeStatus DecodeVecShiftR32Imm(MCInst &Inst, unsigned Imm,
890                                          uint64_t Addr, const void *Decoder) {
891   return DecodeVecShiftRImm(Inst, Imm, 32);
892 }
893 
894 static DecodeStatus DecodeVecShiftR32ImmNarrow(MCInst &Inst, unsigned Imm,
895                                                uint64_t Addr,
896                                                const void *Decoder) {
897   return DecodeVecShiftRImm(Inst, Imm | 0x10, 32);
898 }
899 
900 static DecodeStatus DecodeVecShiftR16Imm(MCInst &Inst, unsigned Imm,
901                                          uint64_t Addr, const void *Decoder) {
902   return DecodeVecShiftRImm(Inst, Imm, 16);
903 }
904 
905 static DecodeStatus DecodeVecShiftR16ImmNarrow(MCInst &Inst, unsigned Imm,
906                                                uint64_t Addr,
907                                                const void *Decoder) {
908   return DecodeVecShiftRImm(Inst, Imm | 0x8, 16);
909 }
910 
911 static DecodeStatus DecodeVecShiftR8Imm(MCInst &Inst, unsigned Imm,
912                                         uint64_t Addr, const void *Decoder) {
913   return DecodeVecShiftRImm(Inst, Imm, 8);
914 }
915 
916 static DecodeStatus DecodeVecShiftL64Imm(MCInst &Inst, unsigned Imm,
917                                          uint64_t Addr, const void *Decoder) {
918   return DecodeVecShiftLImm(Inst, Imm, 64);
919 }
920 
921 static DecodeStatus DecodeVecShiftL32Imm(MCInst &Inst, unsigned Imm,
922                                          uint64_t Addr, const void *Decoder) {
923   return DecodeVecShiftLImm(Inst, Imm, 32);
924 }
925 
926 static DecodeStatus DecodeVecShiftL16Imm(MCInst &Inst, unsigned Imm,
927                                          uint64_t Addr, const void *Decoder) {
928   return DecodeVecShiftLImm(Inst, Imm, 16);
929 }
930 
931 static DecodeStatus DecodeVecShiftL8Imm(MCInst &Inst, unsigned Imm,
932                                         uint64_t Addr, const void *Decoder) {
933   return DecodeVecShiftLImm(Inst, Imm, 8);
934 }
935 
936 static DecodeStatus DecodeThreeAddrSRegInstruction(MCInst &Inst, uint32_t insn,
937                                                    uint64_t Addr,
938                                                    const void *Decoder) {
939   unsigned Rd = fieldFromInstruction(insn, 0, 5);
940   unsigned Rn = fieldFromInstruction(insn, 5, 5);
941   unsigned Rm = fieldFromInstruction(insn, 16, 5);
942   unsigned shiftHi = fieldFromInstruction(insn, 22, 2);
943   unsigned shiftLo = fieldFromInstruction(insn, 10, 6);
944   unsigned shift = (shiftHi << 6) | shiftLo;
945   switch (Inst.getOpcode()) {
946   default:
947     return Fail;
948   case AArch64::ADDWrs:
949   case AArch64::ADDSWrs:
950   case AArch64::SUBWrs:
951   case AArch64::SUBSWrs:
952     // if shift == '11' then ReservedValue()
953     if (shiftHi == 0x3)
954       return Fail;
955     LLVM_FALLTHROUGH;
956   case AArch64::ANDWrs:
957   case AArch64::ANDSWrs:
958   case AArch64::BICWrs:
959   case AArch64::BICSWrs:
960   case AArch64::ORRWrs:
961   case AArch64::ORNWrs:
962   case AArch64::EORWrs:
963   case AArch64::EONWrs: {
964     // if sf == '0' and imm6<5> == '1' then ReservedValue()
965     if (shiftLo >> 5 == 1)
966       return Fail;
967     DecodeGPR32RegisterClass(Inst, Rd, Addr, Decoder);
968     DecodeGPR32RegisterClass(Inst, Rn, Addr, Decoder);
969     DecodeGPR32RegisterClass(Inst, Rm, Addr, Decoder);
970     break;
971   }
972   case AArch64::ADDXrs:
973   case AArch64::ADDSXrs:
974   case AArch64::SUBXrs:
975   case AArch64::SUBSXrs:
976     // if shift == '11' then ReservedValue()
977     if (shiftHi == 0x3)
978       return Fail;
979     LLVM_FALLTHROUGH;
980   case AArch64::ANDXrs:
981   case AArch64::ANDSXrs:
982   case AArch64::BICXrs:
983   case AArch64::BICSXrs:
984   case AArch64::ORRXrs:
985   case AArch64::ORNXrs:
986   case AArch64::EORXrs:
987   case AArch64::EONXrs:
988     DecodeGPR64RegisterClass(Inst, Rd, Addr, Decoder);
989     DecodeGPR64RegisterClass(Inst, Rn, Addr, Decoder);
990     DecodeGPR64RegisterClass(Inst, Rm, Addr, Decoder);
991     break;
992   }
993 
994   Inst.addOperand(MCOperand::createImm(shift));
995   return Success;
996 }
997 
998 static DecodeStatus DecodeMoveImmInstruction(MCInst &Inst, uint32_t insn,
999                                              uint64_t Addr,
1000                                              const void *Decoder) {
1001   unsigned Rd = fieldFromInstruction(insn, 0, 5);
1002   unsigned imm = fieldFromInstruction(insn, 5, 16);
1003   unsigned shift = fieldFromInstruction(insn, 21, 2);
1004   shift <<= 4;
1005   switch (Inst.getOpcode()) {
1006   default:
1007     return Fail;
1008   case AArch64::MOVZWi:
1009   case AArch64::MOVNWi:
1010   case AArch64::MOVKWi:
1011     if (shift & (1U << 5))
1012       return Fail;
1013     DecodeGPR32RegisterClass(Inst, Rd, Addr, Decoder);
1014     break;
1015   case AArch64::MOVZXi:
1016   case AArch64::MOVNXi:
1017   case AArch64::MOVKXi:
1018     DecodeGPR64RegisterClass(Inst, Rd, Addr, Decoder);
1019     break;
1020   }
1021 
1022   if (Inst.getOpcode() == AArch64::MOVKWi ||
1023       Inst.getOpcode() == AArch64::MOVKXi)
1024     Inst.addOperand(Inst.getOperand(0));
1025 
1026   Inst.addOperand(MCOperand::createImm(imm));
1027   Inst.addOperand(MCOperand::createImm(shift));
1028   return Success;
1029 }
1030 
1031 static DecodeStatus DecodeUnsignedLdStInstruction(MCInst &Inst, uint32_t insn,
1032                                                   uint64_t Addr,
1033                                                   const void *Decoder) {
1034   unsigned Rt = fieldFromInstruction(insn, 0, 5);
1035   unsigned Rn = fieldFromInstruction(insn, 5, 5);
1036   unsigned offset = fieldFromInstruction(insn, 10, 12);
1037   const AArch64Disassembler *Dis =
1038       static_cast<const AArch64Disassembler *>(Decoder);
1039 
1040   switch (Inst.getOpcode()) {
1041   default:
1042     return Fail;
1043   case AArch64::PRFMui:
1044     // Rt is an immediate in prefetch.
1045     Inst.addOperand(MCOperand::createImm(Rt));
1046     break;
1047   case AArch64::STRBBui:
1048   case AArch64::LDRBBui:
1049   case AArch64::LDRSBWui:
1050   case AArch64::STRHHui:
1051   case AArch64::LDRHHui:
1052   case AArch64::LDRSHWui:
1053   case AArch64::STRWui:
1054   case AArch64::LDRWui:
1055     DecodeGPR32RegisterClass(Inst, Rt, Addr, Decoder);
1056     break;
1057   case AArch64::LDRSBXui:
1058   case AArch64::LDRSHXui:
1059   case AArch64::LDRSWui:
1060   case AArch64::STRXui:
1061   case AArch64::LDRXui:
1062     DecodeGPR64RegisterClass(Inst, Rt, Addr, Decoder);
1063     break;
1064   case AArch64::LDRQui:
1065   case AArch64::STRQui:
1066     DecodeFPR128RegisterClass(Inst, Rt, Addr, Decoder);
1067     break;
1068   case AArch64::LDRDui:
1069   case AArch64::STRDui:
1070     DecodeFPR64RegisterClass(Inst, Rt, Addr, Decoder);
1071     break;
1072   case AArch64::LDRSui:
1073   case AArch64::STRSui:
1074     DecodeFPR32RegisterClass(Inst, Rt, Addr, Decoder);
1075     break;
1076   case AArch64::LDRHui:
1077   case AArch64::STRHui:
1078     DecodeFPR16RegisterClass(Inst, Rt, Addr, Decoder);
1079     break;
1080   case AArch64::LDRBui:
1081   case AArch64::STRBui:
1082     DecodeFPR8RegisterClass(Inst, Rt, Addr, Decoder);
1083     break;
1084   }
1085 
1086   DecodeGPR64spRegisterClass(Inst, Rn, Addr, Decoder);
1087   if (!Dis->tryAddingSymbolicOperand(Inst, offset, Addr, Fail, 0, 4))
1088     Inst.addOperand(MCOperand::createImm(offset));
1089   return Success;
1090 }
1091 
1092 static DecodeStatus DecodeSignedLdStInstruction(MCInst &Inst, uint32_t insn,
1093                                                 uint64_t Addr,
1094                                                 const void *Decoder) {
1095   unsigned Rt = fieldFromInstruction(insn, 0, 5);
1096   unsigned Rn = fieldFromInstruction(insn, 5, 5);
1097   int64_t offset = fieldFromInstruction(insn, 12, 9);
1098 
1099   // offset is a 9-bit signed immediate, so sign extend it to
1100   // fill the unsigned.
1101   if (offset & (1 << (9 - 1)))
1102     offset |= ~((1LL << 9) - 1);
1103 
1104   // First operand is always the writeback to the address register, if needed.
1105   switch (Inst.getOpcode()) {
1106   default:
1107     break;
1108   case AArch64::LDRSBWpre:
1109   case AArch64::LDRSHWpre:
1110   case AArch64::STRBBpre:
1111   case AArch64::LDRBBpre:
1112   case AArch64::STRHHpre:
1113   case AArch64::LDRHHpre:
1114   case AArch64::STRWpre:
1115   case AArch64::LDRWpre:
1116   case AArch64::LDRSBWpost:
1117   case AArch64::LDRSHWpost:
1118   case AArch64::STRBBpost:
1119   case AArch64::LDRBBpost:
1120   case AArch64::STRHHpost:
1121   case AArch64::LDRHHpost:
1122   case AArch64::STRWpost:
1123   case AArch64::LDRWpost:
1124   case AArch64::LDRSBXpre:
1125   case AArch64::LDRSHXpre:
1126   case AArch64::STRXpre:
1127   case AArch64::LDRSWpre:
1128   case AArch64::LDRXpre:
1129   case AArch64::LDRSBXpost:
1130   case AArch64::LDRSHXpost:
1131   case AArch64::STRXpost:
1132   case AArch64::LDRSWpost:
1133   case AArch64::LDRXpost:
1134   case AArch64::LDRQpre:
1135   case AArch64::STRQpre:
1136   case AArch64::LDRQpost:
1137   case AArch64::STRQpost:
1138   case AArch64::LDRDpre:
1139   case AArch64::STRDpre:
1140   case AArch64::LDRDpost:
1141   case AArch64::STRDpost:
1142   case AArch64::LDRSpre:
1143   case AArch64::STRSpre:
1144   case AArch64::LDRSpost:
1145   case AArch64::STRSpost:
1146   case AArch64::LDRHpre:
1147   case AArch64::STRHpre:
1148   case AArch64::LDRHpost:
1149   case AArch64::STRHpost:
1150   case AArch64::LDRBpre:
1151   case AArch64::STRBpre:
1152   case AArch64::LDRBpost:
1153   case AArch64::STRBpost:
1154     DecodeGPR64spRegisterClass(Inst, Rn, Addr, Decoder);
1155     break;
1156   }
1157 
1158   switch (Inst.getOpcode()) {
1159   default:
1160     return Fail;
1161   case AArch64::PRFUMi:
1162     // Rt is an immediate in prefetch.
1163     Inst.addOperand(MCOperand::createImm(Rt));
1164     break;
1165   case AArch64::STURBBi:
1166   case AArch64::LDURBBi:
1167   case AArch64::LDURSBWi:
1168   case AArch64::STURHHi:
1169   case AArch64::LDURHHi:
1170   case AArch64::LDURSHWi:
1171   case AArch64::STURWi:
1172   case AArch64::LDURWi:
1173   case AArch64::LDTRSBWi:
1174   case AArch64::LDTRSHWi:
1175   case AArch64::STTRWi:
1176   case AArch64::LDTRWi:
1177   case AArch64::STTRHi:
1178   case AArch64::LDTRHi:
1179   case AArch64::LDTRBi:
1180   case AArch64::STTRBi:
1181   case AArch64::LDRSBWpre:
1182   case AArch64::LDRSHWpre:
1183   case AArch64::STRBBpre:
1184   case AArch64::LDRBBpre:
1185   case AArch64::STRHHpre:
1186   case AArch64::LDRHHpre:
1187   case AArch64::STRWpre:
1188   case AArch64::LDRWpre:
1189   case AArch64::LDRSBWpost:
1190   case AArch64::LDRSHWpost:
1191   case AArch64::STRBBpost:
1192   case AArch64::LDRBBpost:
1193   case AArch64::STRHHpost:
1194   case AArch64::LDRHHpost:
1195   case AArch64::STRWpost:
1196   case AArch64::LDRWpost:
1197   case AArch64::STLURBi:
1198   case AArch64::STLURHi:
1199   case AArch64::STLURWi:
1200   case AArch64::LDAPURBi:
1201   case AArch64::LDAPURSBWi:
1202   case AArch64::LDAPURHi:
1203   case AArch64::LDAPURSHWi:
1204   case AArch64::LDAPURi:
1205     DecodeGPR32RegisterClass(Inst, Rt, Addr, Decoder);
1206     break;
1207   case AArch64::LDURSBXi:
1208   case AArch64::LDURSHXi:
1209   case AArch64::LDURSWi:
1210   case AArch64::STURXi:
1211   case AArch64::LDURXi:
1212   case AArch64::LDTRSBXi:
1213   case AArch64::LDTRSHXi:
1214   case AArch64::LDTRSWi:
1215   case AArch64::STTRXi:
1216   case AArch64::LDTRXi:
1217   case AArch64::LDRSBXpre:
1218   case AArch64::LDRSHXpre:
1219   case AArch64::STRXpre:
1220   case AArch64::LDRSWpre:
1221   case AArch64::LDRXpre:
1222   case AArch64::LDRSBXpost:
1223   case AArch64::LDRSHXpost:
1224   case AArch64::STRXpost:
1225   case AArch64::LDRSWpost:
1226   case AArch64::LDRXpost:
1227   case AArch64::LDAPURSWi:
1228   case AArch64::LDAPURSHXi:
1229   case AArch64::LDAPURSBXi:
1230   case AArch64::STLURXi:
1231   case AArch64::LDAPURXi:
1232     DecodeGPR64RegisterClass(Inst, Rt, Addr, Decoder);
1233     break;
1234   case AArch64::LDURQi:
1235   case AArch64::STURQi:
1236   case AArch64::LDRQpre:
1237   case AArch64::STRQpre:
1238   case AArch64::LDRQpost:
1239   case AArch64::STRQpost:
1240     DecodeFPR128RegisterClass(Inst, Rt, Addr, Decoder);
1241     break;
1242   case AArch64::LDURDi:
1243   case AArch64::STURDi:
1244   case AArch64::LDRDpre:
1245   case AArch64::STRDpre:
1246   case AArch64::LDRDpost:
1247   case AArch64::STRDpost:
1248     DecodeFPR64RegisterClass(Inst, Rt, Addr, Decoder);
1249     break;
1250   case AArch64::LDURSi:
1251   case AArch64::STURSi:
1252   case AArch64::LDRSpre:
1253   case AArch64::STRSpre:
1254   case AArch64::LDRSpost:
1255   case AArch64::STRSpost:
1256     DecodeFPR32RegisterClass(Inst, Rt, Addr, Decoder);
1257     break;
1258   case AArch64::LDURHi:
1259   case AArch64::STURHi:
1260   case AArch64::LDRHpre:
1261   case AArch64::STRHpre:
1262   case AArch64::LDRHpost:
1263   case AArch64::STRHpost:
1264     DecodeFPR16RegisterClass(Inst, Rt, Addr, Decoder);
1265     break;
1266   case AArch64::LDURBi:
1267   case AArch64::STURBi:
1268   case AArch64::LDRBpre:
1269   case AArch64::STRBpre:
1270   case AArch64::LDRBpost:
1271   case AArch64::STRBpost:
1272     DecodeFPR8RegisterClass(Inst, Rt, Addr, Decoder);
1273     break;
1274   }
1275 
1276   DecodeGPR64spRegisterClass(Inst, Rn, Addr, Decoder);
1277   Inst.addOperand(MCOperand::createImm(offset));
1278 
1279   bool IsLoad = fieldFromInstruction(insn, 22, 1);
1280   bool IsIndexed = fieldFromInstruction(insn, 10, 2) != 0;
1281   bool IsFP = fieldFromInstruction(insn, 26, 1);
1282 
1283   // Cannot write back to a transfer register (but xzr != sp).
1284   if (IsLoad && IsIndexed && !IsFP && Rn != 31 && Rt == Rn)
1285     return SoftFail;
1286 
1287   return Success;
1288 }
1289 
1290 static DecodeStatus DecodeExclusiveLdStInstruction(MCInst &Inst, uint32_t insn,
1291                                                    uint64_t Addr,
1292                                                    const void *Decoder) {
1293   unsigned Rt = fieldFromInstruction(insn, 0, 5);
1294   unsigned Rn = fieldFromInstruction(insn, 5, 5);
1295   unsigned Rt2 = fieldFromInstruction(insn, 10, 5);
1296   unsigned Rs = fieldFromInstruction(insn, 16, 5);
1297 
1298   unsigned Opcode = Inst.getOpcode();
1299   switch (Opcode) {
1300   default:
1301     return Fail;
1302   case AArch64::STLXRW:
1303   case AArch64::STLXRB:
1304   case AArch64::STLXRH:
1305   case AArch64::STXRW:
1306   case AArch64::STXRB:
1307   case AArch64::STXRH:
1308     DecodeGPR32RegisterClass(Inst, Rs, Addr, Decoder);
1309     LLVM_FALLTHROUGH;
1310   case AArch64::LDARW:
1311   case AArch64::LDARB:
1312   case AArch64::LDARH:
1313   case AArch64::LDAXRW:
1314   case AArch64::LDAXRB:
1315   case AArch64::LDAXRH:
1316   case AArch64::LDXRW:
1317   case AArch64::LDXRB:
1318   case AArch64::LDXRH:
1319   case AArch64::STLRW:
1320   case AArch64::STLRB:
1321   case AArch64::STLRH:
1322   case AArch64::STLLRW:
1323   case AArch64::STLLRB:
1324   case AArch64::STLLRH:
1325   case AArch64::LDLARW:
1326   case AArch64::LDLARB:
1327   case AArch64::LDLARH:
1328     DecodeGPR32RegisterClass(Inst, Rt, Addr, Decoder);
1329     break;
1330   case AArch64::STLXRX:
1331   case AArch64::STXRX:
1332     DecodeGPR32RegisterClass(Inst, Rs, Addr, Decoder);
1333     LLVM_FALLTHROUGH;
1334   case AArch64::LDARX:
1335   case AArch64::LDAXRX:
1336   case AArch64::LDXRX:
1337   case AArch64::STLRX:
1338   case AArch64::LDLARX:
1339   case AArch64::STLLRX:
1340     DecodeGPR64RegisterClass(Inst, Rt, Addr, Decoder);
1341     break;
1342   case AArch64::STLXPW:
1343   case AArch64::STXPW:
1344     DecodeGPR32RegisterClass(Inst, Rs, Addr, Decoder);
1345     LLVM_FALLTHROUGH;
1346   case AArch64::LDAXPW:
1347   case AArch64::LDXPW:
1348     DecodeGPR32RegisterClass(Inst, Rt, Addr, Decoder);
1349     DecodeGPR32RegisterClass(Inst, Rt2, Addr, Decoder);
1350     break;
1351   case AArch64::STLXPX:
1352   case AArch64::STXPX:
1353     DecodeGPR32RegisterClass(Inst, Rs, Addr, Decoder);
1354     LLVM_FALLTHROUGH;
1355   case AArch64::LDAXPX:
1356   case AArch64::LDXPX:
1357     DecodeGPR64RegisterClass(Inst, Rt, Addr, Decoder);
1358     DecodeGPR64RegisterClass(Inst, Rt2, Addr, Decoder);
1359     break;
1360   }
1361 
1362   DecodeGPR64spRegisterClass(Inst, Rn, Addr, Decoder);
1363 
1364   // You shouldn't load to the same register twice in an instruction...
1365   if ((Opcode == AArch64::LDAXPW || Opcode == AArch64::LDXPW ||
1366        Opcode == AArch64::LDAXPX || Opcode == AArch64::LDXPX) &&
1367       Rt == Rt2)
1368     return SoftFail;
1369 
1370   return Success;
1371 }
1372 
1373 static DecodeStatus DecodePairLdStInstruction(MCInst &Inst, uint32_t insn,
1374                                               uint64_t Addr,
1375                                               const void *Decoder) {
1376   unsigned Rt = fieldFromInstruction(insn, 0, 5);
1377   unsigned Rn = fieldFromInstruction(insn, 5, 5);
1378   unsigned Rt2 = fieldFromInstruction(insn, 10, 5);
1379   int64_t offset = fieldFromInstruction(insn, 15, 7);
1380   bool IsLoad = fieldFromInstruction(insn, 22, 1);
1381 
1382   // offset is a 7-bit signed immediate, so sign extend it to
1383   // fill the unsigned.
1384   if (offset & (1 << (7 - 1)))
1385     offset |= ~((1LL << 7) - 1);
1386 
1387   unsigned Opcode = Inst.getOpcode();
1388   bool NeedsDisjointWritebackTransfer = false;
1389 
1390   // First operand is always writeback of base register.
1391   switch (Opcode) {
1392   default:
1393     break;
1394   case AArch64::LDPXpost:
1395   case AArch64::STPXpost:
1396   case AArch64::LDPSWpost:
1397   case AArch64::LDPXpre:
1398   case AArch64::STPXpre:
1399   case AArch64::LDPSWpre:
1400   case AArch64::LDPWpost:
1401   case AArch64::STPWpost:
1402   case AArch64::LDPWpre:
1403   case AArch64::STPWpre:
1404   case AArch64::LDPQpost:
1405   case AArch64::STPQpost:
1406   case AArch64::LDPQpre:
1407   case AArch64::STPQpre:
1408   case AArch64::LDPDpost:
1409   case AArch64::STPDpost:
1410   case AArch64::LDPDpre:
1411   case AArch64::STPDpre:
1412   case AArch64::LDPSpost:
1413   case AArch64::STPSpost:
1414   case AArch64::LDPSpre:
1415   case AArch64::STPSpre:
1416   case AArch64::STGPpre:
1417   case AArch64::STGPpost:
1418     DecodeGPR64spRegisterClass(Inst, Rn, Addr, Decoder);
1419     break;
1420   }
1421 
1422   switch (Opcode) {
1423   default:
1424     return Fail;
1425   case AArch64::LDPXpost:
1426   case AArch64::STPXpost:
1427   case AArch64::LDPSWpost:
1428   case AArch64::LDPXpre:
1429   case AArch64::STPXpre:
1430   case AArch64::LDPSWpre:
1431   case AArch64::STGPpre:
1432   case AArch64::STGPpost:
1433     NeedsDisjointWritebackTransfer = true;
1434     LLVM_FALLTHROUGH;
1435   case AArch64::LDNPXi:
1436   case AArch64::STNPXi:
1437   case AArch64::LDPXi:
1438   case AArch64::STPXi:
1439   case AArch64::LDPSWi:
1440   case AArch64::STGPi:
1441     DecodeGPR64RegisterClass(Inst, Rt, Addr, Decoder);
1442     DecodeGPR64RegisterClass(Inst, Rt2, Addr, Decoder);
1443     break;
1444   case AArch64::LDPWpost:
1445   case AArch64::STPWpost:
1446   case AArch64::LDPWpre:
1447   case AArch64::STPWpre:
1448     NeedsDisjointWritebackTransfer = true;
1449     LLVM_FALLTHROUGH;
1450   case AArch64::LDNPWi:
1451   case AArch64::STNPWi:
1452   case AArch64::LDPWi:
1453   case AArch64::STPWi:
1454     DecodeGPR32RegisterClass(Inst, Rt, Addr, Decoder);
1455     DecodeGPR32RegisterClass(Inst, Rt2, Addr, Decoder);
1456     break;
1457   case AArch64::LDNPQi:
1458   case AArch64::STNPQi:
1459   case AArch64::LDPQpost:
1460   case AArch64::STPQpost:
1461   case AArch64::LDPQi:
1462   case AArch64::STPQi:
1463   case AArch64::LDPQpre:
1464   case AArch64::STPQpre:
1465     DecodeFPR128RegisterClass(Inst, Rt, Addr, Decoder);
1466     DecodeFPR128RegisterClass(Inst, Rt2, Addr, Decoder);
1467     break;
1468   case AArch64::LDNPDi:
1469   case AArch64::STNPDi:
1470   case AArch64::LDPDpost:
1471   case AArch64::STPDpost:
1472   case AArch64::LDPDi:
1473   case AArch64::STPDi:
1474   case AArch64::LDPDpre:
1475   case AArch64::STPDpre:
1476     DecodeFPR64RegisterClass(Inst, Rt, Addr, Decoder);
1477     DecodeFPR64RegisterClass(Inst, Rt2, Addr, Decoder);
1478     break;
1479   case AArch64::LDNPSi:
1480   case AArch64::STNPSi:
1481   case AArch64::LDPSpost:
1482   case AArch64::STPSpost:
1483   case AArch64::LDPSi:
1484   case AArch64::STPSi:
1485   case AArch64::LDPSpre:
1486   case AArch64::STPSpre:
1487     DecodeFPR32RegisterClass(Inst, Rt, Addr, Decoder);
1488     DecodeFPR32RegisterClass(Inst, Rt2, Addr, Decoder);
1489     break;
1490   }
1491 
1492   DecodeGPR64spRegisterClass(Inst, Rn, Addr, Decoder);
1493   Inst.addOperand(MCOperand::createImm(offset));
1494 
1495   // You shouldn't load to the same register twice in an instruction...
1496   if (IsLoad && Rt == Rt2)
1497     return SoftFail;
1498 
1499   // ... or do any operation that writes-back to a transfer register. But note
1500   // that "stp xzr, xzr, [sp], #4" is fine because xzr and sp are different.
1501   if (NeedsDisjointWritebackTransfer && Rn != 31 && (Rt == Rn || Rt2 == Rn))
1502     return SoftFail;
1503 
1504   return Success;
1505 }
1506 
1507 static DecodeStatus DecodeAuthLoadInstruction(MCInst &Inst, uint32_t insn,
1508                                               uint64_t Addr,
1509                                               const void *Decoder) {
1510   unsigned Rt = fieldFromInstruction(insn, 0, 5);
1511   unsigned Rn = fieldFromInstruction(insn, 5, 5);
1512   uint64_t offset = fieldFromInstruction(insn, 22, 1) << 9 |
1513                     fieldFromInstruction(insn, 12, 9);
1514   unsigned writeback = fieldFromInstruction(insn, 11, 1);
1515 
1516   switch (Inst.getOpcode()) {
1517   default:
1518     return Fail;
1519   case AArch64::LDRAAwriteback:
1520   case AArch64::LDRABwriteback:
1521     DecodeGPR64spRegisterClass(Inst, Rn /* writeback register */, Addr,
1522                                Decoder);
1523     break;
1524   case AArch64::LDRAAindexed:
1525   case AArch64::LDRABindexed:
1526     break;
1527   }
1528 
1529   DecodeGPR64RegisterClass(Inst, Rt, Addr, Decoder);
1530   DecodeGPR64spRegisterClass(Inst, Rn, Addr, Decoder);
1531   DecodeSImm<10>(Inst, offset, Addr, Decoder);
1532 
1533   if (writeback && Rt == Rn && Rn != 31) {
1534     return SoftFail;
1535   }
1536 
1537   return Success;
1538 }
1539 
1540 static DecodeStatus DecodeAddSubERegInstruction(MCInst &Inst, uint32_t insn,
1541                                                 uint64_t Addr,
1542                                                 const void *Decoder) {
1543   unsigned Rd = fieldFromInstruction(insn, 0, 5);
1544   unsigned Rn = fieldFromInstruction(insn, 5, 5);
1545   unsigned Rm = fieldFromInstruction(insn, 16, 5);
1546   unsigned extend = fieldFromInstruction(insn, 10, 6);
1547 
1548   unsigned shift = extend & 0x7;
1549   if (shift > 4)
1550     return Fail;
1551 
1552   switch (Inst.getOpcode()) {
1553   default:
1554     return Fail;
1555   case AArch64::ADDWrx:
1556   case AArch64::SUBWrx:
1557     DecodeGPR32spRegisterClass(Inst, Rd, Addr, Decoder);
1558     DecodeGPR32spRegisterClass(Inst, Rn, Addr, Decoder);
1559     DecodeGPR32RegisterClass(Inst, Rm, Addr, Decoder);
1560     break;
1561   case AArch64::ADDSWrx:
1562   case AArch64::SUBSWrx:
1563     DecodeGPR32RegisterClass(Inst, Rd, Addr, Decoder);
1564     DecodeGPR32spRegisterClass(Inst, Rn, Addr, Decoder);
1565     DecodeGPR32RegisterClass(Inst, Rm, Addr, Decoder);
1566     break;
1567   case AArch64::ADDXrx:
1568   case AArch64::SUBXrx:
1569     DecodeGPR64spRegisterClass(Inst, Rd, Addr, Decoder);
1570     DecodeGPR64spRegisterClass(Inst, Rn, Addr, Decoder);
1571     DecodeGPR32RegisterClass(Inst, Rm, Addr, Decoder);
1572     break;
1573   case AArch64::ADDSXrx:
1574   case AArch64::SUBSXrx:
1575     DecodeGPR64RegisterClass(Inst, Rd, Addr, Decoder);
1576     DecodeGPR64spRegisterClass(Inst, Rn, Addr, Decoder);
1577     DecodeGPR32RegisterClass(Inst, Rm, Addr, Decoder);
1578     break;
1579   case AArch64::ADDXrx64:
1580   case AArch64::SUBXrx64:
1581     DecodeGPR64spRegisterClass(Inst, Rd, Addr, Decoder);
1582     DecodeGPR64spRegisterClass(Inst, Rn, Addr, Decoder);
1583     DecodeGPR64RegisterClass(Inst, Rm, Addr, Decoder);
1584     break;
1585   case AArch64::SUBSXrx64:
1586   case AArch64::ADDSXrx64:
1587     DecodeGPR64RegisterClass(Inst, Rd, Addr, Decoder);
1588     DecodeGPR64spRegisterClass(Inst, Rn, Addr, Decoder);
1589     DecodeGPR64RegisterClass(Inst, Rm, Addr, Decoder);
1590     break;
1591   }
1592 
1593   Inst.addOperand(MCOperand::createImm(extend));
1594   return Success;
1595 }
1596 
1597 static DecodeStatus DecodeLogicalImmInstruction(MCInst &Inst, uint32_t insn,
1598                                                 uint64_t Addr,
1599                                                 const void *Decoder) {
1600   unsigned Rd = fieldFromInstruction(insn, 0, 5);
1601   unsigned Rn = fieldFromInstruction(insn, 5, 5);
1602   unsigned Datasize = fieldFromInstruction(insn, 31, 1);
1603   unsigned imm;
1604 
1605   if (Datasize) {
1606     if (Inst.getOpcode() == AArch64::ANDSXri)
1607       DecodeGPR64RegisterClass(Inst, Rd, Addr, Decoder);
1608     else
1609       DecodeGPR64spRegisterClass(Inst, Rd, Addr, Decoder);
1610     DecodeGPR64RegisterClass(Inst, Rn, Addr, Decoder);
1611     imm = fieldFromInstruction(insn, 10, 13);
1612     if (!AArch64_AM::isValidDecodeLogicalImmediate(imm, 64))
1613       return Fail;
1614   } else {
1615     if (Inst.getOpcode() == AArch64::ANDSWri)
1616       DecodeGPR32RegisterClass(Inst, Rd, Addr, Decoder);
1617     else
1618       DecodeGPR32spRegisterClass(Inst, Rd, Addr, Decoder);
1619     DecodeGPR32RegisterClass(Inst, Rn, Addr, Decoder);
1620     imm = fieldFromInstruction(insn, 10, 12);
1621     if (!AArch64_AM::isValidDecodeLogicalImmediate(imm, 32))
1622       return Fail;
1623   }
1624   Inst.addOperand(MCOperand::createImm(imm));
1625   return Success;
1626 }
1627 
1628 static DecodeStatus DecodeModImmInstruction(MCInst &Inst, uint32_t insn,
1629                                             uint64_t Addr,
1630                                             const void *Decoder) {
1631   unsigned Rd = fieldFromInstruction(insn, 0, 5);
1632   unsigned cmode = fieldFromInstruction(insn, 12, 4);
1633   unsigned imm = fieldFromInstruction(insn, 16, 3) << 5;
1634   imm |= fieldFromInstruction(insn, 5, 5);
1635 
1636   if (Inst.getOpcode() == AArch64::MOVID)
1637     DecodeFPR64RegisterClass(Inst, Rd, Addr, Decoder);
1638   else
1639     DecodeVectorRegisterClass(Inst, Rd, Addr, Decoder);
1640 
1641   Inst.addOperand(MCOperand::createImm(imm));
1642 
1643   switch (Inst.getOpcode()) {
1644   default:
1645     break;
1646   case AArch64::MOVIv4i16:
1647   case AArch64::MOVIv8i16:
1648   case AArch64::MVNIv4i16:
1649   case AArch64::MVNIv8i16:
1650   case AArch64::MOVIv2i32:
1651   case AArch64::MOVIv4i32:
1652   case AArch64::MVNIv2i32:
1653   case AArch64::MVNIv4i32:
1654     Inst.addOperand(MCOperand::createImm((cmode & 6) << 2));
1655     break;
1656   case AArch64::MOVIv2s_msl:
1657   case AArch64::MOVIv4s_msl:
1658   case AArch64::MVNIv2s_msl:
1659   case AArch64::MVNIv4s_msl:
1660     Inst.addOperand(MCOperand::createImm((cmode & 1) ? 0x110 : 0x108));
1661     break;
1662   }
1663 
1664   return Success;
1665 }
1666 
1667 static DecodeStatus DecodeModImmTiedInstruction(MCInst &Inst, uint32_t insn,
1668                                                 uint64_t Addr,
1669                                                 const void *Decoder) {
1670   unsigned Rd = fieldFromInstruction(insn, 0, 5);
1671   unsigned cmode = fieldFromInstruction(insn, 12, 4);
1672   unsigned imm = fieldFromInstruction(insn, 16, 3) << 5;
1673   imm |= fieldFromInstruction(insn, 5, 5);
1674 
1675   // Tied operands added twice.
1676   DecodeVectorRegisterClass(Inst, Rd, Addr, Decoder);
1677   DecodeVectorRegisterClass(Inst, Rd, Addr, Decoder);
1678 
1679   Inst.addOperand(MCOperand::createImm(imm));
1680   Inst.addOperand(MCOperand::createImm((cmode & 6) << 2));
1681 
1682   return Success;
1683 }
1684 
1685 static DecodeStatus DecodeAdrInstruction(MCInst &Inst, uint32_t insn,
1686                                          uint64_t Addr, const void *Decoder) {
1687   unsigned Rd = fieldFromInstruction(insn, 0, 5);
1688   int64_t imm = fieldFromInstruction(insn, 5, 19) << 2;
1689   imm |= fieldFromInstruction(insn, 29, 2);
1690   const AArch64Disassembler *Dis =
1691       static_cast<const AArch64Disassembler *>(Decoder);
1692 
1693   // Sign-extend the 21-bit immediate.
1694   if (imm & (1 << (21 - 1)))
1695     imm |= ~((1LL << 21) - 1);
1696 
1697   DecodeGPR64RegisterClass(Inst, Rd, Addr, Decoder);
1698   if (!Dis->tryAddingSymbolicOperand(Inst, imm, Addr, Fail, 0, 4))
1699     Inst.addOperand(MCOperand::createImm(imm));
1700 
1701   return Success;
1702 }
1703 
1704 static DecodeStatus DecodeAddSubImmShift(MCInst &Inst, uint32_t insn,
1705                                          uint64_t Addr, const void *Decoder) {
1706   unsigned Rd = fieldFromInstruction(insn, 0, 5);
1707   unsigned Rn = fieldFromInstruction(insn, 5, 5);
1708   unsigned Imm = fieldFromInstruction(insn, 10, 14);
1709   unsigned S = fieldFromInstruction(insn, 29, 1);
1710   unsigned Datasize = fieldFromInstruction(insn, 31, 1);
1711 
1712   unsigned ShifterVal = (Imm >> 12) & 3;
1713   unsigned ImmVal = Imm & 0xFFF;
1714   const AArch64Disassembler *Dis =
1715       static_cast<const AArch64Disassembler *>(Decoder);
1716 
1717   if (ShifterVal != 0 && ShifterVal != 1)
1718     return Fail;
1719 
1720   if (Datasize) {
1721     if (Rd == 31 && !S)
1722       DecodeGPR64spRegisterClass(Inst, Rd, Addr, Decoder);
1723     else
1724       DecodeGPR64RegisterClass(Inst, Rd, Addr, Decoder);
1725     DecodeGPR64spRegisterClass(Inst, Rn, Addr, Decoder);
1726   } else {
1727     if (Rd == 31 && !S)
1728       DecodeGPR32spRegisterClass(Inst, Rd, Addr, Decoder);
1729     else
1730       DecodeGPR32RegisterClass(Inst, Rd, Addr, Decoder);
1731     DecodeGPR32spRegisterClass(Inst, Rn, Addr, Decoder);
1732   }
1733 
1734   if (!Dis->tryAddingSymbolicOperand(Inst, Imm, Addr, Fail, 0, 4))
1735     Inst.addOperand(MCOperand::createImm(ImmVal));
1736   Inst.addOperand(MCOperand::createImm(12 * ShifterVal));
1737   return Success;
1738 }
1739 
1740 static DecodeStatus DecodeUnconditionalBranch(MCInst &Inst, uint32_t insn,
1741                                               uint64_t Addr,
1742                                               const void *Decoder) {
1743   int64_t imm = fieldFromInstruction(insn, 0, 26);
1744   const AArch64Disassembler *Dis =
1745       static_cast<const AArch64Disassembler *>(Decoder);
1746 
1747   // Sign-extend the 26-bit immediate.
1748   if (imm & (1 << (26 - 1)))
1749     imm |= ~((1LL << 26) - 1);
1750 
1751   if (!Dis->tryAddingSymbolicOperand(Inst, imm * 4, Addr, true, 0, 4))
1752     Inst.addOperand(MCOperand::createImm(imm));
1753 
1754   return Success;
1755 }
1756 
1757 static DecodeStatus DecodeSystemPStateInstruction(MCInst &Inst, uint32_t insn,
1758                                                   uint64_t Addr,
1759                                                   const void *Decoder) {
1760   uint64_t op1 = fieldFromInstruction(insn, 16, 3);
1761   uint64_t op2 = fieldFromInstruction(insn, 5, 3);
1762   uint64_t crm = fieldFromInstruction(insn, 8, 4);
1763   uint64_t pstate_field = (op1 << 3) | op2;
1764 
1765   switch (pstate_field) {
1766   case 0x01: // XAFlag
1767   case 0x02: // AXFlag
1768     return Fail;
1769   }
1770 
1771   if ((pstate_field == AArch64PState::PAN  ||
1772        pstate_field == AArch64PState::UAO  ||
1773        pstate_field == AArch64PState::SSBS) && crm > 1)
1774     return Fail;
1775 
1776   Inst.addOperand(MCOperand::createImm(pstate_field));
1777   Inst.addOperand(MCOperand::createImm(crm));
1778 
1779   const AArch64Disassembler *Dis =
1780       static_cast<const AArch64Disassembler *>(Decoder);
1781   auto PState = AArch64PState::lookupPStateByEncoding(pstate_field);
1782   if (PState && PState->haveFeatures(Dis->getSubtargetInfo().getFeatureBits()))
1783     return Success;
1784   return Fail;
1785 }
1786 
1787 static DecodeStatus DecodeTestAndBranch(MCInst &Inst, uint32_t insn,
1788                                         uint64_t Addr, const void *Decoder) {
1789   uint64_t Rt = fieldFromInstruction(insn, 0, 5);
1790   uint64_t bit = fieldFromInstruction(insn, 31, 1) << 5;
1791   bit |= fieldFromInstruction(insn, 19, 5);
1792   int64_t dst = fieldFromInstruction(insn, 5, 14);
1793   const AArch64Disassembler *Dis =
1794       static_cast<const AArch64Disassembler *>(Decoder);
1795 
1796   // Sign-extend 14-bit immediate.
1797   if (dst & (1 << (14 - 1)))
1798     dst |= ~((1LL << 14) - 1);
1799 
1800   if (fieldFromInstruction(insn, 31, 1) == 0)
1801     DecodeGPR32RegisterClass(Inst, Rt, Addr, Decoder);
1802   else
1803     DecodeGPR64RegisterClass(Inst, Rt, Addr, Decoder);
1804   Inst.addOperand(MCOperand::createImm(bit));
1805   if (!Dis->tryAddingSymbolicOperand(Inst, dst * 4, Addr, true, 0, 4))
1806     Inst.addOperand(MCOperand::createImm(dst));
1807 
1808   return Success;
1809 }
1810 
1811 static DecodeStatus DecodeGPRSeqPairsClassRegisterClass(MCInst &Inst,
1812                                                         unsigned RegClassID,
1813                                                         unsigned RegNo,
1814                                                         uint64_t Addr,
1815                                                         const void *Decoder) {
1816   // Register number must be even (see CASP instruction)
1817   if (RegNo & 0x1)
1818     return Fail;
1819 
1820   unsigned Reg = AArch64MCRegisterClasses[RegClassID].getRegister(RegNo / 2);
1821   Inst.addOperand(MCOperand::createReg(Reg));
1822   return Success;
1823 }
1824 
1825 static DecodeStatus DecodeWSeqPairsClassRegisterClass(MCInst &Inst,
1826                                                       unsigned RegNo,
1827                                                       uint64_t Addr,
1828                                                       const void *Decoder) {
1829   return DecodeGPRSeqPairsClassRegisterClass(Inst,
1830                                              AArch64::WSeqPairsClassRegClassID,
1831                                              RegNo, Addr, Decoder);
1832 }
1833 
1834 static DecodeStatus DecodeXSeqPairsClassRegisterClass(MCInst &Inst,
1835                                                       unsigned RegNo,
1836                                                       uint64_t Addr,
1837                                                       const void *Decoder) {
1838   return DecodeGPRSeqPairsClassRegisterClass(Inst,
1839                                              AArch64::XSeqPairsClassRegClassID,
1840                                              RegNo, Addr, Decoder);
1841 }
1842 
1843 static DecodeStatus DecodeSVELogicalImmInstruction(llvm::MCInst &Inst,
1844                                                    uint32_t insn,
1845                                                    uint64_t Addr,
1846                                                    const void *Decoder) {
1847   unsigned Zdn = fieldFromInstruction(insn, 0, 5);
1848   unsigned imm = fieldFromInstruction(insn, 5, 13);
1849   if (!AArch64_AM::isValidDecodeLogicalImmediate(imm, 64))
1850     return Fail;
1851 
1852   // The same (tied) operand is added twice to the instruction.
1853   DecodeZPRRegisterClass(Inst, Zdn, Addr, Decoder);
1854   if (Inst.getOpcode() != AArch64::DUPM_ZI)
1855     DecodeZPRRegisterClass(Inst, Zdn, Addr, Decoder);
1856   Inst.addOperand(MCOperand::createImm(imm));
1857   return Success;
1858 }
1859 
1860 template<int Bits>
1861 static DecodeStatus DecodeSImm(llvm::MCInst &Inst, uint64_t Imm,
1862                                uint64_t Address, const void *Decoder) {
1863   if (Imm & ~((1LL << Bits) - 1))
1864       return Fail;
1865 
1866   // Imm is a signed immediate, so sign extend it.
1867   if (Imm & (1 << (Bits - 1)))
1868     Imm |= ~((1LL << Bits) - 1);
1869 
1870   Inst.addOperand(MCOperand::createImm(Imm));
1871   return Success;
1872 }
1873 
1874 // Decode 8-bit signed/unsigned immediate for a given element width.
1875 template <int ElementWidth>
1876 static DecodeStatus DecodeImm8OptLsl(MCInst &Inst, unsigned Imm,
1877                                       uint64_t Addr, const void *Decoder) {
1878   unsigned Val = (uint8_t)Imm;
1879   unsigned Shift = (Imm & 0x100) ? 8 : 0;
1880   if (ElementWidth == 8 && Shift)
1881     return Fail;
1882   Inst.addOperand(MCOperand::createImm(Val));
1883   Inst.addOperand(MCOperand::createImm(Shift));
1884   return Success;
1885 }
1886 
1887 // Decode uimm4 ranged from 1-16.
1888 static DecodeStatus DecodeSVEIncDecImm(MCInst &Inst, unsigned Imm,
1889                                        uint64_t Addr, const void *Decoder) {
1890   Inst.addOperand(MCOperand::createImm(Imm + 1));
1891   return Success;
1892 }
1893