xref: /llvm-project/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp (revision 7116e8963df0f3507b86c36953b22d4958b299f1)
1 //===- AMDGPUDisassembler.cpp - Disassembler for AMDGPU ISA ---------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //===----------------------------------------------------------------------===//
11 //
12 /// \file
13 ///
14 /// This file contains definition for AMDGPU ISA disassembler
15 //
16 //===----------------------------------------------------------------------===//
17 
18 // ToDo: What to do with instruction suffixes (v_mov_b32 vs v_mov_b32_e32)?
19 
20 #include "Disassembler/AMDGPUDisassembler.h"
21 #include "AMDGPU.h"
22 #include "AMDGPURegisterInfo.h"
23 #include "SIDefines.h"
24 #include "Utils/AMDGPUBaseInfo.h"
25 #include "llvm-c/Disassembler.h"
26 #include "llvm/ADT/APInt.h"
27 #include "llvm/ADT/ArrayRef.h"
28 #include "llvm/ADT/Twine.h"
29 #include "llvm/BinaryFormat/ELF.h"
30 #include "llvm/MC/MCContext.h"
31 #include "llvm/MC/MCDisassembler/MCDisassembler.h"
32 #include "llvm/MC/MCExpr.h"
33 #include "llvm/MC/MCFixedLenDisassembler.h"
34 #include "llvm/MC/MCInst.h"
35 #include "llvm/MC/MCSubtargetInfo.h"
36 #include "llvm/Support/Endian.h"
37 #include "llvm/Support/ErrorHandling.h"
38 #include "llvm/Support/MathExtras.h"
39 #include "llvm/Support/TargetRegistry.h"
40 #include "llvm/Support/raw_ostream.h"
41 #include <algorithm>
42 #include <cassert>
43 #include <cstddef>
44 #include <cstdint>
45 #include <iterator>
46 #include <tuple>
47 #include <vector>
48 
49 using namespace llvm;
50 
51 #define DEBUG_TYPE "amdgpu-disassembler"
52 
53 using DecodeStatus = llvm::MCDisassembler::DecodeStatus;
54 
55 inline static MCDisassembler::DecodeStatus
56 addOperand(MCInst &Inst, const MCOperand& Opnd) {
57   Inst.addOperand(Opnd);
58   return Opnd.isValid() ?
59     MCDisassembler::Success :
60     MCDisassembler::SoftFail;
61 }
62 
63 static int insertNamedMCOperand(MCInst &MI, const MCOperand &Op,
64                                 uint16_t NameIdx) {
65   int OpIdx = AMDGPU::getNamedOperandIdx(MI.getOpcode(), NameIdx);
66   if (OpIdx != -1) {
67     auto I = MI.begin();
68     std::advance(I, OpIdx);
69     MI.insert(I, Op);
70   }
71   return OpIdx;
72 }
73 
74 static DecodeStatus decodeSoppBrTarget(MCInst &Inst, unsigned Imm,
75                                        uint64_t Addr, const void *Decoder) {
76   auto DAsm = static_cast<const AMDGPUDisassembler*>(Decoder);
77 
78   APInt SignedOffset(18, Imm * 4, true);
79   int64_t Offset = (SignedOffset.sext(64) + 4 + Addr).getSExtValue();
80 
81   if (DAsm->tryAddingSymbolicOperand(Inst, Offset, Addr, true, 2, 2))
82     return MCDisassembler::Success;
83   return addOperand(Inst, MCOperand::createImm(Imm));
84 }
85 
86 #define DECODE_OPERAND(StaticDecoderName, DecoderName) \
87 static DecodeStatus StaticDecoderName(MCInst &Inst, \
88                                        unsigned Imm, \
89                                        uint64_t /*Addr*/, \
90                                        const void *Decoder) { \
91   auto DAsm = static_cast<const AMDGPUDisassembler*>(Decoder); \
92   return addOperand(Inst, DAsm->DecoderName(Imm)); \
93 }
94 
95 #define DECODE_OPERAND_REG(RegClass) \
96 DECODE_OPERAND(Decode##RegClass##RegisterClass, decodeOperand_##RegClass)
97 
98 DECODE_OPERAND_REG(VGPR_32)
99 DECODE_OPERAND_REG(VS_32)
100 DECODE_OPERAND_REG(VS_64)
101 DECODE_OPERAND_REG(VS_128)
102 
103 DECODE_OPERAND_REG(VReg_64)
104 DECODE_OPERAND_REG(VReg_96)
105 DECODE_OPERAND_REG(VReg_128)
106 
107 DECODE_OPERAND_REG(SReg_32)
108 DECODE_OPERAND_REG(SReg_32_XM0_XEXEC)
109 DECODE_OPERAND_REG(SReg_32_XEXEC_HI)
110 DECODE_OPERAND_REG(SReg_64)
111 DECODE_OPERAND_REG(SReg_64_XEXEC)
112 DECODE_OPERAND_REG(SReg_128)
113 DECODE_OPERAND_REG(SReg_256)
114 DECODE_OPERAND_REG(SReg_512)
115 
116 static DecodeStatus decodeOperand_VSrc16(MCInst &Inst,
117                                          unsigned Imm,
118                                          uint64_t Addr,
119                                          const void *Decoder) {
120   auto DAsm = static_cast<const AMDGPUDisassembler*>(Decoder);
121   return addOperand(Inst, DAsm->decodeOperand_VSrc16(Imm));
122 }
123 
124 static DecodeStatus decodeOperand_VSrcV216(MCInst &Inst,
125                                          unsigned Imm,
126                                          uint64_t Addr,
127                                          const void *Decoder) {
128   auto DAsm = static_cast<const AMDGPUDisassembler*>(Decoder);
129   return addOperand(Inst, DAsm->decodeOperand_VSrcV216(Imm));
130 }
131 
132 #define DECODE_SDWA(DecName) \
133 DECODE_OPERAND(decodeSDWA##DecName, decodeSDWA##DecName)
134 
135 DECODE_SDWA(Src32)
136 DECODE_SDWA(Src16)
137 DECODE_SDWA(VopcDst)
138 
139 #include "AMDGPUGenDisassemblerTables.inc"
140 
141 //===----------------------------------------------------------------------===//
142 //
143 //===----------------------------------------------------------------------===//
144 
145 template <typename T> static inline T eatBytes(ArrayRef<uint8_t>& Bytes) {
146   assert(Bytes.size() >= sizeof(T));
147   const auto Res = support::endian::read<T, support::endianness::little>(Bytes.data());
148   Bytes = Bytes.slice(sizeof(T));
149   return Res;
150 }
151 
152 DecodeStatus AMDGPUDisassembler::tryDecodeInst(const uint8_t* Table,
153                                                MCInst &MI,
154                                                uint64_t Inst,
155                                                uint64_t Address) const {
156   assert(MI.getOpcode() == 0);
157   assert(MI.getNumOperands() == 0);
158   MCInst TmpInst;
159   HasLiteral = false;
160   const auto SavedBytes = Bytes;
161   if (decodeInstruction(Table, TmpInst, Inst, Address, this, STI)) {
162     MI = TmpInst;
163     return MCDisassembler::Success;
164   }
165   Bytes = SavedBytes;
166   return MCDisassembler::Fail;
167 }
168 
169 DecodeStatus AMDGPUDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
170                                                 ArrayRef<uint8_t> Bytes_,
171                                                 uint64_t Address,
172                                                 raw_ostream &WS,
173                                                 raw_ostream &CS) const {
174   CommentStream = &CS;
175   bool IsSDWA = false;
176 
177   // ToDo: AMDGPUDisassembler supports only VI ISA.
178   if (!STI.getFeatureBits()[AMDGPU::FeatureGCN3Encoding])
179     report_fatal_error("Disassembly not yet supported for subtarget");
180 
181   const unsigned MaxInstBytesNum = (std::min)((size_t)8, Bytes_.size());
182   Bytes = Bytes_.slice(0, MaxInstBytesNum);
183 
184   DecodeStatus Res = MCDisassembler::Fail;
185   do {
186     // ToDo: better to switch encoding length using some bit predicate
187     // but it is unknown yet, so try all we can
188 
189     // Try to decode DPP and SDWA first to solve conflict with VOP1 and VOP2
190     // encodings
191     if (Bytes.size() >= 8) {
192       const uint64_t QW = eatBytes<uint64_t>(Bytes);
193       Res = tryDecodeInst(DecoderTableDPP64, MI, QW, Address);
194       if (Res) break;
195 
196       Res = tryDecodeInst(DecoderTableSDWA64, MI, QW, Address);
197       if (Res) { IsSDWA = true;  break; }
198 
199       Res = tryDecodeInst(DecoderTableSDWA964, MI, QW, Address);
200       if (Res) { IsSDWA = true;  break; }
201 
202       if (STI.getFeatureBits()[AMDGPU::FeatureUnpackedD16VMem]) {
203         Res = tryDecodeInst(DecoderTableGFX80_UNPACKED64, MI, QW, Address);
204         if (Res) break;
205       }
206     }
207 
208     // Reinitialize Bytes as DPP64 could have eaten too much
209     Bytes = Bytes_.slice(0, MaxInstBytesNum);
210 
211     // Try decode 32-bit instruction
212     if (Bytes.size() < 4) break;
213     const uint32_t DW = eatBytes<uint32_t>(Bytes);
214     Res = tryDecodeInst(DecoderTableVI32, MI, DW, Address);
215     if (Res) break;
216 
217     Res = tryDecodeInst(DecoderTableAMDGPU32, MI, DW, Address);
218     if (Res) break;
219 
220     Res = tryDecodeInst(DecoderTableGFX932, MI, DW, Address);
221     if (Res) break;
222 
223     if (Bytes.size() < 4) break;
224     const uint64_t QW = ((uint64_t)eatBytes<uint32_t>(Bytes) << 32) | DW;
225     Res = tryDecodeInst(DecoderTableVI64, MI, QW, Address);
226     if (Res) break;
227 
228     Res = tryDecodeInst(DecoderTableAMDGPU64, MI, QW, Address);
229     if (Res) break;
230 
231     Res = tryDecodeInst(DecoderTableGFX964, MI, QW, Address);
232   } while (false);
233 
234   if (Res && (MI.getOpcode() == AMDGPU::V_MAC_F32_e64_vi ||
235               MI.getOpcode() == AMDGPU::V_MAC_F32_e64_si ||
236               MI.getOpcode() == AMDGPU::V_MAC_F16_e64_vi)) {
237     // Insert dummy unused src2_modifiers.
238     insertNamedMCOperand(MI, MCOperand::createImm(0),
239                          AMDGPU::OpName::src2_modifiers);
240   }
241 
242   if (Res && (MCII->get(MI.getOpcode()).TSFlags & SIInstrFlags::MIMG)) {
243     Res = convertMIMGInst(MI);
244   }
245 
246   if (Res && IsSDWA)
247     Res = convertSDWAInst(MI);
248 
249   // if the opcode was not recognized we'll assume a Size of 4 bytes
250   // (unless there are fewer bytes left)
251   Size = Res ? (MaxInstBytesNum - Bytes.size())
252              : std::min((size_t)4, Bytes_.size());
253   return Res;
254 }
255 
256 DecodeStatus AMDGPUDisassembler::convertSDWAInst(MCInst &MI) const {
257   if (STI.getFeatureBits()[AMDGPU::FeatureGFX9]) {
258     if (AMDGPU::getNamedOperandIdx(MI.getOpcode(), AMDGPU::OpName::sdst) != -1)
259       // VOPC - insert clamp
260       insertNamedMCOperand(MI, MCOperand::createImm(0), AMDGPU::OpName::clamp);
261   } else if (STI.getFeatureBits()[AMDGPU::FeatureVolcanicIslands]) {
262     int SDst = AMDGPU::getNamedOperandIdx(MI.getOpcode(), AMDGPU::OpName::sdst);
263     if (SDst != -1) {
264       // VOPC - insert VCC register as sdst
265       insertNamedMCOperand(MI, createRegOperand(AMDGPU::VCC),
266                            AMDGPU::OpName::sdst);
267     } else {
268       // VOP1/2 - insert omod if present in instruction
269       insertNamedMCOperand(MI, MCOperand::createImm(0), AMDGPU::OpName::omod);
270     }
271   }
272   return MCDisassembler::Success;
273 }
274 
275 // Note that MIMG format provides no information about VADDR size.
276 // Consequently, decoded instructions always show address
277 // as if it has 1 dword, which could be not really so.
278 DecodeStatus AMDGPUDisassembler::convertMIMGInst(MCInst &MI) const {
279 
280   if (MCII->get(MI.getOpcode()).TSFlags & SIInstrFlags::Gather4) {
281     return MCDisassembler::Success;
282   }
283 
284   int VDstIdx = AMDGPU::getNamedOperandIdx(MI.getOpcode(),
285                                            AMDGPU::OpName::vdst);
286 
287   int VDataIdx = AMDGPU::getNamedOperandIdx(MI.getOpcode(),
288                                             AMDGPU::OpName::vdata);
289 
290   int DMaskIdx = AMDGPU::getNamedOperandIdx(MI.getOpcode(),
291                                             AMDGPU::OpName::dmask);
292 
293   int TFEIdx   = AMDGPU::getNamedOperandIdx(MI.getOpcode(),
294                                             AMDGPU::OpName::tfe);
295 
296   assert(VDataIdx != -1);
297   assert(DMaskIdx != -1);
298   assert(TFEIdx != -1);
299 
300   bool IsAtomic = (VDstIdx != -1);
301 
302   unsigned DMask = MI.getOperand(DMaskIdx).getImm() & 0xf;
303   if (DMask == 0)
304     return MCDisassembler::Success;
305 
306   unsigned DstSize = countPopulation(DMask);
307   if (DstSize == 1)
308     return MCDisassembler::Success;
309 
310   bool D16 = MCII->get(MI.getOpcode()).TSFlags & SIInstrFlags::D16;
311   if (D16 && AMDGPU::hasPackedD16(STI)) {
312     DstSize = (DstSize + 1) / 2;
313   }
314 
315   // FIXME: Add tfe support
316   if (MI.getOperand(TFEIdx).getImm())
317     return MCDisassembler::Success;
318 
319   int NewOpcode = -1;
320 
321   if (IsAtomic) {
322     if (DMask == 0x1 || DMask == 0x3 || DMask == 0xF) {
323       NewOpcode = AMDGPU::getMaskedMIMGAtomicOp(*MCII, MI.getOpcode(), DstSize);
324     }
325     if (NewOpcode == -1) return MCDisassembler::Success;
326   } else {
327     NewOpcode = AMDGPU::getMaskedMIMGOp(*MCII, MI.getOpcode(), DstSize);
328     assert(NewOpcode != -1 && "could not find matching mimg channel instruction");
329   }
330 
331   auto RCID = MCII->get(NewOpcode).OpInfo[VDataIdx].RegClass;
332 
333   // Get first subregister of VData
334   unsigned Vdata0 = MI.getOperand(VDataIdx).getReg();
335   unsigned VdataSub0 = MRI.getSubReg(Vdata0, AMDGPU::sub0);
336   Vdata0 = (VdataSub0 != 0)? VdataSub0 : Vdata0;
337 
338   // Widen the register to the correct number of enabled channels.
339   auto NewVdata = MRI.getMatchingSuperReg(Vdata0, AMDGPU::sub0,
340                                           &MRI.getRegClass(RCID));
341   if (NewVdata == AMDGPU::NoRegister) {
342     // It's possible to encode this such that the low register + enabled
343     // components exceeds the register count.
344     return MCDisassembler::Success;
345   }
346 
347   MI.setOpcode(NewOpcode);
348   // vaddr will be always appear as a single VGPR. This will look different than
349   // how it is usually emitted because the number of register components is not
350   // in the instruction encoding.
351   MI.getOperand(VDataIdx) = MCOperand::createReg(NewVdata);
352 
353   if (IsAtomic) {
354     // Atomic operations have an additional operand (a copy of data)
355     MI.getOperand(VDstIdx) = MCOperand::createReg(NewVdata);
356   }
357 
358   return MCDisassembler::Success;
359 }
360 
361 const char* AMDGPUDisassembler::getRegClassName(unsigned RegClassID) const {
362   return getContext().getRegisterInfo()->
363     getRegClassName(&AMDGPUMCRegisterClasses[RegClassID]);
364 }
365 
366 inline
367 MCOperand AMDGPUDisassembler::errOperand(unsigned V,
368                                          const Twine& ErrMsg) const {
369   *CommentStream << "Error: " + ErrMsg;
370 
371   // ToDo: add support for error operands to MCInst.h
372   // return MCOperand::createError(V);
373   return MCOperand();
374 }
375 
376 inline
377 MCOperand AMDGPUDisassembler::createRegOperand(unsigned int RegId) const {
378   return MCOperand::createReg(AMDGPU::getMCReg(RegId, STI));
379 }
380 
381 inline
382 MCOperand AMDGPUDisassembler::createRegOperand(unsigned RegClassID,
383                                                unsigned Val) const {
384   const auto& RegCl = AMDGPUMCRegisterClasses[RegClassID];
385   if (Val >= RegCl.getNumRegs())
386     return errOperand(Val, Twine(getRegClassName(RegClassID)) +
387                            ": unknown register " + Twine(Val));
388   return createRegOperand(RegCl.getRegister(Val));
389 }
390 
391 inline
392 MCOperand AMDGPUDisassembler::createSRegOperand(unsigned SRegClassID,
393                                                 unsigned Val) const {
394   // ToDo: SI/CI have 104 SGPRs, VI - 102
395   // Valery: here we accepting as much as we can, let assembler sort it out
396   int shift = 0;
397   switch (SRegClassID) {
398   case AMDGPU::SGPR_32RegClassID:
399   case AMDGPU::TTMP_32RegClassID:
400     break;
401   case AMDGPU::SGPR_64RegClassID:
402   case AMDGPU::TTMP_64RegClassID:
403     shift = 1;
404     break;
405   case AMDGPU::SGPR_128RegClassID:
406   case AMDGPU::TTMP_128RegClassID:
407   // ToDo: unclear if s[100:104] is available on VI. Can we use VCC as SGPR in
408   // this bundle?
409   case AMDGPU::SGPR_256RegClassID:
410   case AMDGPU::TTMP_256RegClassID:
411     // ToDo: unclear if s[96:104] is available on VI. Can we use VCC as SGPR in
412   // this bundle?
413   case AMDGPU::SGPR_512RegClassID:
414   case AMDGPU::TTMP_512RegClassID:
415     shift = 2;
416     break;
417   // ToDo: unclear if s[88:104] is available on VI. Can we use VCC as SGPR in
418   // this bundle?
419   default:
420     llvm_unreachable("unhandled register class");
421   }
422 
423   if (Val % (1 << shift)) {
424     *CommentStream << "Warning: " << getRegClassName(SRegClassID)
425                    << ": scalar reg isn't aligned " << Val;
426   }
427 
428   return createRegOperand(SRegClassID, Val >> shift);
429 }
430 
431 MCOperand AMDGPUDisassembler::decodeOperand_VS_32(unsigned Val) const {
432   return decodeSrcOp(OPW32, Val);
433 }
434 
435 MCOperand AMDGPUDisassembler::decodeOperand_VS_64(unsigned Val) const {
436   return decodeSrcOp(OPW64, Val);
437 }
438 
439 MCOperand AMDGPUDisassembler::decodeOperand_VS_128(unsigned Val) const {
440   return decodeSrcOp(OPW128, Val);
441 }
442 
443 MCOperand AMDGPUDisassembler::decodeOperand_VSrc16(unsigned Val) const {
444   return decodeSrcOp(OPW16, Val);
445 }
446 
447 MCOperand AMDGPUDisassembler::decodeOperand_VSrcV216(unsigned Val) const {
448   return decodeSrcOp(OPWV216, Val);
449 }
450 
451 MCOperand AMDGPUDisassembler::decodeOperand_VGPR_32(unsigned Val) const {
452   // Some instructions have operand restrictions beyond what the encoding
453   // allows. Some ordinarily VSrc_32 operands are VGPR_32, so clear the extra
454   // high bit.
455   Val &= 255;
456 
457   return createRegOperand(AMDGPU::VGPR_32RegClassID, Val);
458 }
459 
460 MCOperand AMDGPUDisassembler::decodeOperand_VReg_64(unsigned Val) const {
461   return createRegOperand(AMDGPU::VReg_64RegClassID, Val);
462 }
463 
464 MCOperand AMDGPUDisassembler::decodeOperand_VReg_96(unsigned Val) const {
465   return createRegOperand(AMDGPU::VReg_96RegClassID, Val);
466 }
467 
468 MCOperand AMDGPUDisassembler::decodeOperand_VReg_128(unsigned Val) const {
469   return createRegOperand(AMDGPU::VReg_128RegClassID, Val);
470 }
471 
472 MCOperand AMDGPUDisassembler::decodeOperand_SReg_32(unsigned Val) const {
473   // table-gen generated disassembler doesn't care about operand types
474   // leaving only registry class so SSrc_32 operand turns into SReg_32
475   // and therefore we accept immediates and literals here as well
476   return decodeSrcOp(OPW32, Val);
477 }
478 
479 MCOperand AMDGPUDisassembler::decodeOperand_SReg_32_XM0_XEXEC(
480   unsigned Val) const {
481   // SReg_32_XM0 is SReg_32 without M0 or EXEC_LO/EXEC_HI
482   return decodeOperand_SReg_32(Val);
483 }
484 
485 MCOperand AMDGPUDisassembler::decodeOperand_SReg_32_XEXEC_HI(
486   unsigned Val) const {
487   // SReg_32_XM0 is SReg_32 without EXEC_HI
488   return decodeOperand_SReg_32(Val);
489 }
490 
491 MCOperand AMDGPUDisassembler::decodeOperand_SReg_64(unsigned Val) const {
492   return decodeSrcOp(OPW64, Val);
493 }
494 
495 MCOperand AMDGPUDisassembler::decodeOperand_SReg_64_XEXEC(unsigned Val) const {
496   return decodeSrcOp(OPW64, Val);
497 }
498 
499 MCOperand AMDGPUDisassembler::decodeOperand_SReg_128(unsigned Val) const {
500   return decodeSrcOp(OPW128, Val);
501 }
502 
503 MCOperand AMDGPUDisassembler::decodeOperand_SReg_256(unsigned Val) const {
504   return decodeDstOp(OPW256, Val);
505 }
506 
507 MCOperand AMDGPUDisassembler::decodeOperand_SReg_512(unsigned Val) const {
508   return decodeDstOp(OPW512, Val);
509 }
510 
511 MCOperand AMDGPUDisassembler::decodeLiteralConstant() const {
512   // For now all literal constants are supposed to be unsigned integer
513   // ToDo: deal with signed/unsigned 64-bit integer constants
514   // ToDo: deal with float/double constants
515   if (!HasLiteral) {
516     if (Bytes.size() < 4) {
517       return errOperand(0, "cannot read literal, inst bytes left " +
518                         Twine(Bytes.size()));
519     }
520     HasLiteral = true;
521     Literal = eatBytes<uint32_t>(Bytes);
522   }
523   return MCOperand::createImm(Literal);
524 }
525 
526 MCOperand AMDGPUDisassembler::decodeIntImmed(unsigned Imm) {
527   using namespace AMDGPU::EncValues;
528 
529   assert(Imm >= INLINE_INTEGER_C_MIN && Imm <= INLINE_INTEGER_C_MAX);
530   return MCOperand::createImm((Imm <= INLINE_INTEGER_C_POSITIVE_MAX) ?
531     (static_cast<int64_t>(Imm) - INLINE_INTEGER_C_MIN) :
532     (INLINE_INTEGER_C_POSITIVE_MAX - static_cast<int64_t>(Imm)));
533       // Cast prevents negative overflow.
534 }
535 
536 static int64_t getInlineImmVal32(unsigned Imm) {
537   switch (Imm) {
538   case 240:
539     return FloatToBits(0.5f);
540   case 241:
541     return FloatToBits(-0.5f);
542   case 242:
543     return FloatToBits(1.0f);
544   case 243:
545     return FloatToBits(-1.0f);
546   case 244:
547     return FloatToBits(2.0f);
548   case 245:
549     return FloatToBits(-2.0f);
550   case 246:
551     return FloatToBits(4.0f);
552   case 247:
553     return FloatToBits(-4.0f);
554   case 248: // 1 / (2 * PI)
555     return 0x3e22f983;
556   default:
557     llvm_unreachable("invalid fp inline imm");
558   }
559 }
560 
561 static int64_t getInlineImmVal64(unsigned Imm) {
562   switch (Imm) {
563   case 240:
564     return DoubleToBits(0.5);
565   case 241:
566     return DoubleToBits(-0.5);
567   case 242:
568     return DoubleToBits(1.0);
569   case 243:
570     return DoubleToBits(-1.0);
571   case 244:
572     return DoubleToBits(2.0);
573   case 245:
574     return DoubleToBits(-2.0);
575   case 246:
576     return DoubleToBits(4.0);
577   case 247:
578     return DoubleToBits(-4.0);
579   case 248: // 1 / (2 * PI)
580     return 0x3fc45f306dc9c882;
581   default:
582     llvm_unreachable("invalid fp inline imm");
583   }
584 }
585 
586 static int64_t getInlineImmVal16(unsigned Imm) {
587   switch (Imm) {
588   case 240:
589     return 0x3800;
590   case 241:
591     return 0xB800;
592   case 242:
593     return 0x3C00;
594   case 243:
595     return 0xBC00;
596   case 244:
597     return 0x4000;
598   case 245:
599     return 0xC000;
600   case 246:
601     return 0x4400;
602   case 247:
603     return 0xC400;
604   case 248: // 1 / (2 * PI)
605     return 0x3118;
606   default:
607     llvm_unreachable("invalid fp inline imm");
608   }
609 }
610 
611 MCOperand AMDGPUDisassembler::decodeFPImmed(OpWidthTy Width, unsigned Imm) {
612   assert(Imm >= AMDGPU::EncValues::INLINE_FLOATING_C_MIN
613       && Imm <= AMDGPU::EncValues::INLINE_FLOATING_C_MAX);
614 
615   // ToDo: case 248: 1/(2*PI) - is allowed only on VI
616   switch (Width) {
617   case OPW32:
618     return MCOperand::createImm(getInlineImmVal32(Imm));
619   case OPW64:
620     return MCOperand::createImm(getInlineImmVal64(Imm));
621   case OPW16:
622   case OPWV216:
623     return MCOperand::createImm(getInlineImmVal16(Imm));
624   default:
625     llvm_unreachable("implement me");
626   }
627 }
628 
629 unsigned AMDGPUDisassembler::getVgprClassId(const OpWidthTy Width) const {
630   using namespace AMDGPU;
631 
632   assert(OPW_FIRST_ <= Width && Width < OPW_LAST_);
633   switch (Width) {
634   default: // fall
635   case OPW32:
636   case OPW16:
637   case OPWV216:
638     return VGPR_32RegClassID;
639   case OPW64: return VReg_64RegClassID;
640   case OPW128: return VReg_128RegClassID;
641   }
642 }
643 
644 unsigned AMDGPUDisassembler::getSgprClassId(const OpWidthTy Width) const {
645   using namespace AMDGPU;
646 
647   assert(OPW_FIRST_ <= Width && Width < OPW_LAST_);
648   switch (Width) {
649   default: // fall
650   case OPW32:
651   case OPW16:
652   case OPWV216:
653     return SGPR_32RegClassID;
654   case OPW64: return SGPR_64RegClassID;
655   case OPW128: return SGPR_128RegClassID;
656   case OPW256: return SGPR_256RegClassID;
657   case OPW512: return SGPR_512RegClassID;
658   }
659 }
660 
661 unsigned AMDGPUDisassembler::getTtmpClassId(const OpWidthTy Width) const {
662   using namespace AMDGPU;
663 
664   assert(OPW_FIRST_ <= Width && Width < OPW_LAST_);
665   switch (Width) {
666   default: // fall
667   case OPW32:
668   case OPW16:
669   case OPWV216:
670     return TTMP_32RegClassID;
671   case OPW64: return TTMP_64RegClassID;
672   case OPW128: return TTMP_128RegClassID;
673   case OPW256: return TTMP_256RegClassID;
674   case OPW512: return TTMP_512RegClassID;
675   }
676 }
677 
678 int AMDGPUDisassembler::getTTmpIdx(unsigned Val) const {
679   using namespace AMDGPU::EncValues;
680 
681   unsigned TTmpMin = isGFX9() ? TTMP_GFX9_MIN : TTMP_VI_MIN;
682   unsigned TTmpMax = isGFX9() ? TTMP_GFX9_MAX : TTMP_VI_MAX;
683 
684   return (TTmpMin <= Val && Val <= TTmpMax)? Val - TTmpMin : -1;
685 }
686 
687 MCOperand AMDGPUDisassembler::decodeSrcOp(const OpWidthTy Width, unsigned Val) const {
688   using namespace AMDGPU::EncValues;
689 
690   assert(Val < 512); // enum9
691 
692   if (VGPR_MIN <= Val && Val <= VGPR_MAX) {
693     return createRegOperand(getVgprClassId(Width), Val - VGPR_MIN);
694   }
695   if (Val <= SGPR_MAX) {
696     assert(SGPR_MIN == 0); // "SGPR_MIN <= Val" is always true and causes compilation warning.
697     return createSRegOperand(getSgprClassId(Width), Val - SGPR_MIN);
698   }
699 
700   int TTmpIdx = getTTmpIdx(Val);
701   if (TTmpIdx >= 0) {
702     return createSRegOperand(getTtmpClassId(Width), TTmpIdx);
703   }
704 
705   if (INLINE_INTEGER_C_MIN <= Val && Val <= INLINE_INTEGER_C_MAX)
706     return decodeIntImmed(Val);
707 
708   if (INLINE_FLOATING_C_MIN <= Val && Val <= INLINE_FLOATING_C_MAX)
709     return decodeFPImmed(Width, Val);
710 
711   if (Val == LITERAL_CONST)
712     return decodeLiteralConstant();
713 
714   switch (Width) {
715   case OPW32:
716   case OPW16:
717   case OPWV216:
718     return decodeSpecialReg32(Val);
719   case OPW64:
720     return decodeSpecialReg64(Val);
721   default:
722     llvm_unreachable("unexpected immediate type");
723   }
724 }
725 
726 MCOperand AMDGPUDisassembler::decodeDstOp(const OpWidthTy Width, unsigned Val) const {
727   using namespace AMDGPU::EncValues;
728 
729   assert(Val < 128);
730   assert(Width == OPW256 || Width == OPW512);
731 
732   if (Val <= SGPR_MAX) {
733     assert(SGPR_MIN == 0); // "SGPR_MIN <= Val" is always true and causes compilation warning.
734     return createSRegOperand(getSgprClassId(Width), Val - SGPR_MIN);
735   }
736 
737   int TTmpIdx = getTTmpIdx(Val);
738   if (TTmpIdx >= 0) {
739     return createSRegOperand(getTtmpClassId(Width), TTmpIdx);
740   }
741 
742   llvm_unreachable("unknown dst register");
743 }
744 
745 MCOperand AMDGPUDisassembler::decodeSpecialReg32(unsigned Val) const {
746   using namespace AMDGPU;
747 
748   switch (Val) {
749   case 102: return createRegOperand(FLAT_SCR_LO);
750   case 103: return createRegOperand(FLAT_SCR_HI);
751   case 104: return createRegOperand(XNACK_MASK_LO);
752   case 105: return createRegOperand(XNACK_MASK_HI);
753   case 106: return createRegOperand(VCC_LO);
754   case 107: return createRegOperand(VCC_HI);
755   case 108: assert(!isGFX9()); return createRegOperand(TBA_LO);
756   case 109: assert(!isGFX9()); return createRegOperand(TBA_HI);
757   case 110: assert(!isGFX9()); return createRegOperand(TMA_LO);
758   case 111: assert(!isGFX9()); return createRegOperand(TMA_HI);
759   case 124: return createRegOperand(M0);
760   case 126: return createRegOperand(EXEC_LO);
761   case 127: return createRegOperand(EXEC_HI);
762   case 235: return createRegOperand(SRC_SHARED_BASE);
763   case 236: return createRegOperand(SRC_SHARED_LIMIT);
764   case 237: return createRegOperand(SRC_PRIVATE_BASE);
765   case 238: return createRegOperand(SRC_PRIVATE_LIMIT);
766     // TODO: SRC_POPS_EXITING_WAVE_ID
767     // ToDo: no support for vccz register
768   case 251: break;
769     // ToDo: no support for execz register
770   case 252: break;
771   case 253: return createRegOperand(SCC);
772   default: break;
773   }
774   return errOperand(Val, "unknown operand encoding " + Twine(Val));
775 }
776 
777 MCOperand AMDGPUDisassembler::decodeSpecialReg64(unsigned Val) const {
778   using namespace AMDGPU;
779 
780   switch (Val) {
781   case 102: return createRegOperand(FLAT_SCR);
782   case 104: return createRegOperand(XNACK_MASK);
783   case 106: return createRegOperand(VCC);
784   case 108: assert(!isGFX9()); return createRegOperand(TBA);
785   case 110: assert(!isGFX9()); return createRegOperand(TMA);
786   case 126: return createRegOperand(EXEC);
787   default: break;
788   }
789   return errOperand(Val, "unknown operand encoding " + Twine(Val));
790 }
791 
792 MCOperand AMDGPUDisassembler::decodeSDWASrc(const OpWidthTy Width,
793                                             const unsigned Val) const {
794   using namespace AMDGPU::SDWA;
795   using namespace AMDGPU::EncValues;
796 
797   if (STI.getFeatureBits()[AMDGPU::FeatureGFX9]) {
798     // XXX: static_cast<int> is needed to avoid stupid warning:
799     // compare with unsigned is always true
800     if (SDWA9EncValues::SRC_VGPR_MIN <= static_cast<int>(Val) &&
801         Val <= SDWA9EncValues::SRC_VGPR_MAX) {
802       return createRegOperand(getVgprClassId(Width),
803                               Val - SDWA9EncValues::SRC_VGPR_MIN);
804     }
805     if (SDWA9EncValues::SRC_SGPR_MIN <= Val &&
806         Val <= SDWA9EncValues::SRC_SGPR_MAX) {
807       return createSRegOperand(getSgprClassId(Width),
808                                Val - SDWA9EncValues::SRC_SGPR_MIN);
809     }
810     if (SDWA9EncValues::SRC_TTMP_MIN <= Val &&
811         Val <= SDWA9EncValues::SRC_TTMP_MAX) {
812       return createSRegOperand(getTtmpClassId(Width),
813                                Val - SDWA9EncValues::SRC_TTMP_MIN);
814     }
815 
816     const unsigned SVal = Val - SDWA9EncValues::SRC_SGPR_MIN;
817 
818     if (INLINE_INTEGER_C_MIN <= SVal && SVal <= INLINE_INTEGER_C_MAX)
819       return decodeIntImmed(SVal);
820 
821     if (INLINE_FLOATING_C_MIN <= SVal && SVal <= INLINE_FLOATING_C_MAX)
822       return decodeFPImmed(Width, SVal);
823 
824     return decodeSpecialReg32(SVal);
825   } else if (STI.getFeatureBits()[AMDGPU::FeatureVolcanicIslands]) {
826     return createRegOperand(getVgprClassId(Width), Val);
827   }
828   llvm_unreachable("unsupported target");
829 }
830 
831 MCOperand AMDGPUDisassembler::decodeSDWASrc16(unsigned Val) const {
832   return decodeSDWASrc(OPW16, Val);
833 }
834 
835 MCOperand AMDGPUDisassembler::decodeSDWASrc32(unsigned Val) const {
836   return decodeSDWASrc(OPW32, Val);
837 }
838 
839 MCOperand AMDGPUDisassembler::decodeSDWAVopcDst(unsigned Val) const {
840   using namespace AMDGPU::SDWA;
841 
842   assert(STI.getFeatureBits()[AMDGPU::FeatureGFX9] &&
843          "SDWAVopcDst should be present only on GFX9");
844   if (Val & SDWA9EncValues::VOPC_DST_VCC_MASK) {
845     Val &= SDWA9EncValues::VOPC_DST_SGPR_MASK;
846 
847     int TTmpIdx = getTTmpIdx(Val);
848     if (TTmpIdx >= 0) {
849       return createSRegOperand(getTtmpClassId(OPW64), TTmpIdx);
850     } else if (Val > AMDGPU::EncValues::SGPR_MAX) {
851       return decodeSpecialReg64(Val);
852     } else {
853       return createSRegOperand(getSgprClassId(OPW64), Val);
854     }
855   } else {
856     return createRegOperand(AMDGPU::VCC);
857   }
858 }
859 
860 bool AMDGPUDisassembler::isVI() const {
861   return STI.getFeatureBits()[AMDGPU::FeatureVolcanicIslands];
862 }
863 
864 bool AMDGPUDisassembler::isGFX9() const {
865   return STI.getFeatureBits()[AMDGPU::FeatureGFX9];
866 }
867 
868 //===----------------------------------------------------------------------===//
869 // AMDGPUSymbolizer
870 //===----------------------------------------------------------------------===//
871 
872 // Try to find symbol name for specified label
873 bool AMDGPUSymbolizer::tryAddingSymbolicOperand(MCInst &Inst,
874                                 raw_ostream &/*cStream*/, int64_t Value,
875                                 uint64_t /*Address*/, bool IsBranch,
876                                 uint64_t /*Offset*/, uint64_t /*InstSize*/) {
877   using SymbolInfoTy = std::tuple<uint64_t, StringRef, uint8_t>;
878   using SectionSymbolsTy = std::vector<SymbolInfoTy>;
879 
880   if (!IsBranch) {
881     return false;
882   }
883 
884   auto *Symbols = static_cast<SectionSymbolsTy *>(DisInfo);
885   auto Result = std::find_if(Symbols->begin(), Symbols->end(),
886                              [Value](const SymbolInfoTy& Val) {
887                                 return std::get<0>(Val) == static_cast<uint64_t>(Value)
888                                     && std::get<2>(Val) == ELF::STT_NOTYPE;
889                              });
890   if (Result != Symbols->end()) {
891     auto *Sym = Ctx.getOrCreateSymbol(std::get<1>(*Result));
892     const auto *Add = MCSymbolRefExpr::create(Sym, Ctx);
893     Inst.addOperand(MCOperand::createExpr(Add));
894     return true;
895   }
896   return false;
897 }
898 
899 void AMDGPUSymbolizer::tryAddingPcLoadReferenceComment(raw_ostream &cStream,
900                                                        int64_t Value,
901                                                        uint64_t Address) {
902   llvm_unreachable("unimplemented");
903 }
904 
905 //===----------------------------------------------------------------------===//
906 // Initialization
907 //===----------------------------------------------------------------------===//
908 
909 static MCSymbolizer *createAMDGPUSymbolizer(const Triple &/*TT*/,
910                               LLVMOpInfoCallback /*GetOpInfo*/,
911                               LLVMSymbolLookupCallback /*SymbolLookUp*/,
912                               void *DisInfo,
913                               MCContext *Ctx,
914                               std::unique_ptr<MCRelocationInfo> &&RelInfo) {
915   return new AMDGPUSymbolizer(*Ctx, std::move(RelInfo), DisInfo);
916 }
917 
918 static MCDisassembler *createAMDGPUDisassembler(const Target &T,
919                                                 const MCSubtargetInfo &STI,
920                                                 MCContext &Ctx) {
921   return new AMDGPUDisassembler(STI, Ctx, T.createMCInstrInfo());
922 }
923 
924 extern "C" void LLVMInitializeAMDGPUDisassembler() {
925   TargetRegistry::RegisterMCDisassembler(getTheGCNTarget(),
926                                          createAMDGPUDisassembler);
927   TargetRegistry::RegisterMCSymbolizer(getTheGCNTarget(),
928                                        createAMDGPUSymbolizer);
929 }
930