xref: /freebsd/contrib/llvm-project/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCCodeEmitter.cpp (revision 7fdf597e96a02165cfe22ff357b857d5fa15ed8a)
1 //===-- AMDGPUMCCodeEmitter.cpp - AMDGPU Code Emitter ---------------------===//
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 /// \file
10 /// The AMDGPU code emitter produces machine code that can be executed
11 /// directly on the GPU device.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "MCTargetDesc/AMDGPUFixupKinds.h"
16 #include "MCTargetDesc/AMDGPUMCTargetDesc.h"
17 #include "SIDefines.h"
18 #include "Utils/AMDGPUBaseInfo.h"
19 #include "llvm/ADT/APInt.h"
20 #include "llvm/MC/MCCodeEmitter.h"
21 #include "llvm/MC/MCContext.h"
22 #include "llvm/MC/MCExpr.h"
23 #include "llvm/MC/MCInstrInfo.h"
24 #include "llvm/MC/MCRegisterInfo.h"
25 #include "llvm/MC/MCSubtargetInfo.h"
26 #include "llvm/Support/Casting.h"
27 #include "llvm/Support/EndianStream.h"
28 #include "llvm/TargetParser/SubtargetFeature.h"
29 #include <optional>
30 
31 using namespace llvm;
32 
33 namespace {
34 
35 class AMDGPUMCCodeEmitter : public MCCodeEmitter {
36   const MCRegisterInfo &MRI;
37   const MCInstrInfo &MCII;
38 
39 public:
40   AMDGPUMCCodeEmitter(const MCInstrInfo &MCII, const MCRegisterInfo &MRI)
41       : MRI(MRI), MCII(MCII) {}
42 
43   /// Encode the instruction and write it to the OS.
44   void encodeInstruction(const MCInst &MI, SmallVectorImpl<char> &CB,
45                          SmallVectorImpl<MCFixup> &Fixups,
46                          const MCSubtargetInfo &STI) const override;
47 
48   void getMachineOpValue(const MCInst &MI, const MCOperand &MO, APInt &Op,
49                          SmallVectorImpl<MCFixup> &Fixups,
50                          const MCSubtargetInfo &STI) const;
51 
52   void getMachineOpValueT16(const MCInst &MI, unsigned OpNo, APInt &Op,
53                             SmallVectorImpl<MCFixup> &Fixups,
54                             const MCSubtargetInfo &STI) const;
55 
56   void getMachineOpValueT16Lo128(const MCInst &MI, unsigned OpNo, APInt &Op,
57                                  SmallVectorImpl<MCFixup> &Fixups,
58                                  const MCSubtargetInfo &STI) const;
59 
60   /// Use a fixup to encode the simm16 field for SOPP branch
61   ///        instructions.
62   void getSOPPBrEncoding(const MCInst &MI, unsigned OpNo, APInt &Op,
63                          SmallVectorImpl<MCFixup> &Fixups,
64                          const MCSubtargetInfo &STI) const;
65 
66   void getSMEMOffsetEncoding(const MCInst &MI, unsigned OpNo, APInt &Op,
67                              SmallVectorImpl<MCFixup> &Fixups,
68                              const MCSubtargetInfo &STI) const;
69 
70   void getSDWASrcEncoding(const MCInst &MI, unsigned OpNo, APInt &Op,
71                           SmallVectorImpl<MCFixup> &Fixups,
72                           const MCSubtargetInfo &STI) const;
73 
74   void getSDWAVopcDstEncoding(const MCInst &MI, unsigned OpNo, APInt &Op,
75                               SmallVectorImpl<MCFixup> &Fixups,
76                               const MCSubtargetInfo &STI) const;
77 
78   void getAVOperandEncoding(const MCInst &MI, unsigned OpNo, APInt &Op,
79                             SmallVectorImpl<MCFixup> &Fixups,
80                             const MCSubtargetInfo &STI) const;
81 
82 private:
83   uint64_t getImplicitOpSelHiEncoding(int Opcode) const;
84   void getMachineOpValueCommon(const MCInst &MI, const MCOperand &MO,
85                                unsigned OpNo, APInt &Op,
86                                SmallVectorImpl<MCFixup> &Fixups,
87                                const MCSubtargetInfo &STI) const;
88 
89   /// Encode an fp or int literal.
90   std::optional<uint32_t> getLitEncoding(const MCOperand &MO,
91                                          const MCOperandInfo &OpInfo,
92                                          const MCSubtargetInfo &STI) const;
93 
94   void getBinaryCodeForInstr(const MCInst &MI, SmallVectorImpl<MCFixup> &Fixups,
95                              APInt &Inst, APInt &Scratch,
96                              const MCSubtargetInfo &STI) const;
97 };
98 
99 } // end anonymous namespace
100 
101 MCCodeEmitter *llvm::createAMDGPUMCCodeEmitter(const MCInstrInfo &MCII,
102                                                MCContext &Ctx) {
103   return new AMDGPUMCCodeEmitter(MCII, *Ctx.getRegisterInfo());
104 }
105 
106 // Returns the encoding value to use if the given integer is an integer inline
107 // immediate value, or 0 if it is not.
108 template <typename IntTy>
109 static uint32_t getIntInlineImmEncoding(IntTy Imm) {
110   if (Imm >= 0 && Imm <= 64)
111     return 128 + Imm;
112 
113   if (Imm >= -16 && Imm <= -1)
114     return 192 + std::abs(Imm);
115 
116   return 0;
117 }
118 
119 static uint32_t getLit16Encoding(uint16_t Val, const MCSubtargetInfo &STI) {
120   uint16_t IntImm = getIntInlineImmEncoding(static_cast<int16_t>(Val));
121   if (IntImm != 0)
122     return IntImm;
123 
124   if (Val == 0x3800) // 0.5
125     return 240;
126 
127   if (Val == 0xB800) // -0.5
128     return 241;
129 
130   if (Val == 0x3C00) // 1.0
131     return 242;
132 
133   if (Val == 0xBC00) // -1.0
134     return 243;
135 
136   if (Val == 0x4000) // 2.0
137     return 244;
138 
139   if (Val == 0xC000) // -2.0
140     return 245;
141 
142   if (Val == 0x4400) // 4.0
143     return 246;
144 
145   if (Val == 0xC400) // -4.0
146     return 247;
147 
148   if (Val == 0x3118 && // 1.0 / (2.0 * pi)
149       STI.hasFeature(AMDGPU::FeatureInv2PiInlineImm))
150     return 248;
151 
152   return 255;
153 }
154 
155 static uint32_t getLitBF16Encoding(uint16_t Val) {
156   uint16_t IntImm = getIntInlineImmEncoding(static_cast<int16_t>(Val));
157   if (IntImm != 0)
158     return IntImm;
159 
160   // clang-format off
161   switch (Val) {
162   case 0x3F00: return 240; // 0.5
163   case 0xBF00: return 241; // -0.5
164   case 0x3F80: return 242; // 1.0
165   case 0xBF80: return 243; // -1.0
166   case 0x4000: return 244; // 2.0
167   case 0xC000: return 245; // -2.0
168   case 0x4080: return 246; // 4.0
169   case 0xC080: return 247; // -4.0
170   case 0x3E22: return 248; // 1.0 / (2.0 * pi)
171   default:     return 255;
172   }
173   // clang-format on
174 }
175 
176 static uint32_t getLit32Encoding(uint32_t Val, const MCSubtargetInfo &STI) {
177   uint32_t IntImm = getIntInlineImmEncoding(static_cast<int32_t>(Val));
178   if (IntImm != 0)
179     return IntImm;
180 
181   if (Val == llvm::bit_cast<uint32_t>(0.5f))
182     return 240;
183 
184   if (Val == llvm::bit_cast<uint32_t>(-0.5f))
185     return 241;
186 
187   if (Val == llvm::bit_cast<uint32_t>(1.0f))
188     return 242;
189 
190   if (Val == llvm::bit_cast<uint32_t>(-1.0f))
191     return 243;
192 
193   if (Val == llvm::bit_cast<uint32_t>(2.0f))
194     return 244;
195 
196   if (Val == llvm::bit_cast<uint32_t>(-2.0f))
197     return 245;
198 
199   if (Val == llvm::bit_cast<uint32_t>(4.0f))
200     return 246;
201 
202   if (Val == llvm::bit_cast<uint32_t>(-4.0f))
203     return 247;
204 
205   if (Val == 0x3e22f983 && // 1.0 / (2.0 * pi)
206       STI.hasFeature(AMDGPU::FeatureInv2PiInlineImm))
207     return 248;
208 
209   return 255;
210 }
211 
212 static uint32_t getLit16IntEncoding(uint32_t Val, const MCSubtargetInfo &STI) {
213   return getLit32Encoding(Val, STI);
214 }
215 
216 static uint32_t getLit64Encoding(uint64_t Val, const MCSubtargetInfo &STI) {
217   uint32_t IntImm = getIntInlineImmEncoding(static_cast<int64_t>(Val));
218   if (IntImm != 0)
219     return IntImm;
220 
221   if (Val == llvm::bit_cast<uint64_t>(0.5))
222     return 240;
223 
224   if (Val == llvm::bit_cast<uint64_t>(-0.5))
225     return 241;
226 
227   if (Val == llvm::bit_cast<uint64_t>(1.0))
228     return 242;
229 
230   if (Val == llvm::bit_cast<uint64_t>(-1.0))
231     return 243;
232 
233   if (Val == llvm::bit_cast<uint64_t>(2.0))
234     return 244;
235 
236   if (Val == llvm::bit_cast<uint64_t>(-2.0))
237     return 245;
238 
239   if (Val == llvm::bit_cast<uint64_t>(4.0))
240     return 246;
241 
242   if (Val == llvm::bit_cast<uint64_t>(-4.0))
243     return 247;
244 
245   if (Val == 0x3fc45f306dc9c882 && // 1.0 / (2.0 * pi)
246       STI.hasFeature(AMDGPU::FeatureInv2PiInlineImm))
247     return 248;
248 
249   return 255;
250 }
251 
252 std::optional<uint32_t>
253 AMDGPUMCCodeEmitter::getLitEncoding(const MCOperand &MO,
254                                     const MCOperandInfo &OpInfo,
255                                     const MCSubtargetInfo &STI) const {
256   int64_t Imm;
257   if (MO.isExpr()) {
258     const auto *C = dyn_cast<MCConstantExpr>(MO.getExpr());
259     if (!C)
260       return 255;
261 
262     Imm = C->getValue();
263   } else {
264 
265     assert(!MO.isDFPImm());
266 
267     if (!MO.isImm())
268       return {};
269 
270     Imm = MO.getImm();
271   }
272 
273   switch (OpInfo.OperandType) {
274   case AMDGPU::OPERAND_REG_IMM_INT32:
275   case AMDGPU::OPERAND_REG_IMM_FP32:
276   case AMDGPU::OPERAND_REG_IMM_FP32_DEFERRED:
277   case AMDGPU::OPERAND_REG_INLINE_C_INT32:
278   case AMDGPU::OPERAND_REG_INLINE_C_FP32:
279   case AMDGPU::OPERAND_REG_INLINE_AC_INT32:
280   case AMDGPU::OPERAND_REG_INLINE_AC_FP32:
281   case AMDGPU::OPERAND_REG_IMM_V2INT32:
282   case AMDGPU::OPERAND_REG_IMM_V2FP32:
283   case AMDGPU::OPERAND_REG_INLINE_C_V2INT32:
284   case AMDGPU::OPERAND_REG_INLINE_C_V2FP32:
285   case AMDGPU::OPERAND_INLINE_SPLIT_BARRIER_INT32:
286     return getLit32Encoding(static_cast<uint32_t>(Imm), STI);
287 
288   case AMDGPU::OPERAND_REG_IMM_INT64:
289   case AMDGPU::OPERAND_REG_IMM_FP64:
290   case AMDGPU::OPERAND_REG_INLINE_C_INT64:
291   case AMDGPU::OPERAND_REG_INLINE_C_FP64:
292   case AMDGPU::OPERAND_REG_INLINE_AC_FP64:
293     return getLit64Encoding(static_cast<uint64_t>(Imm), STI);
294 
295   case AMDGPU::OPERAND_REG_IMM_INT16:
296   case AMDGPU::OPERAND_REG_INLINE_C_INT16:
297   case AMDGPU::OPERAND_REG_INLINE_AC_INT16:
298     return getLit16IntEncoding(static_cast<uint32_t>(Imm), STI);
299 
300   case AMDGPU::OPERAND_REG_IMM_FP16:
301   case AMDGPU::OPERAND_REG_IMM_FP16_DEFERRED:
302   case AMDGPU::OPERAND_REG_INLINE_C_FP16:
303   case AMDGPU::OPERAND_REG_INLINE_AC_FP16:
304     // FIXME Is this correct? What do inline immediates do on SI for f16 src
305     // which does not have f16 support?
306     return getLit16Encoding(static_cast<uint16_t>(Imm), STI);
307 
308   case AMDGPU::OPERAND_REG_IMM_BF16:
309   case AMDGPU::OPERAND_REG_IMM_BF16_DEFERRED:
310   case AMDGPU::OPERAND_REG_INLINE_C_BF16:
311   case AMDGPU::OPERAND_REG_INLINE_AC_BF16:
312     // We don't actually need to check Inv2Pi here because BF16 instructions can
313     // only be emitted for targets that already support the feature.
314     return getLitBF16Encoding(static_cast<uint16_t>(Imm));
315 
316   case AMDGPU::OPERAND_REG_IMM_V2INT16:
317   case AMDGPU::OPERAND_REG_INLINE_C_V2INT16:
318   case AMDGPU::OPERAND_REG_INLINE_AC_V2INT16:
319     return AMDGPU::getInlineEncodingV2I16(static_cast<uint32_t>(Imm))
320         .value_or(255);
321 
322   case AMDGPU::OPERAND_REG_IMM_V2FP16:
323   case AMDGPU::OPERAND_REG_INLINE_C_V2FP16:
324   case AMDGPU::OPERAND_REG_INLINE_AC_V2FP16:
325     return AMDGPU::getInlineEncodingV2F16(static_cast<uint32_t>(Imm))
326         .value_or(255);
327 
328   case AMDGPU::OPERAND_REG_IMM_V2BF16:
329   case AMDGPU::OPERAND_REG_INLINE_C_V2BF16:
330   case AMDGPU::OPERAND_REG_INLINE_AC_V2BF16:
331     return AMDGPU::getInlineEncodingV2BF16(static_cast<uint32_t>(Imm))
332         .value_or(255);
333 
334   case AMDGPU::OPERAND_KIMM32:
335   case AMDGPU::OPERAND_KIMM16:
336     return MO.getImm();
337   default:
338     llvm_unreachable("invalid operand size");
339   }
340 }
341 
342 uint64_t AMDGPUMCCodeEmitter::getImplicitOpSelHiEncoding(int Opcode) const {
343   using namespace AMDGPU::VOP3PEncoding;
344   using namespace AMDGPU::OpName;
345 
346   if (AMDGPU::hasNamedOperand(Opcode, op_sel_hi)) {
347     if (AMDGPU::hasNamedOperand(Opcode, src2))
348       return 0;
349     if (AMDGPU::hasNamedOperand(Opcode, src1))
350       return OP_SEL_HI_2;
351     if (AMDGPU::hasNamedOperand(Opcode, src0))
352       return OP_SEL_HI_1 | OP_SEL_HI_2;
353   }
354   return OP_SEL_HI_0 | OP_SEL_HI_1 | OP_SEL_HI_2;
355 }
356 
357 static bool isVCMPX64(const MCInstrDesc &Desc) {
358   return (Desc.TSFlags & SIInstrFlags::VOP3) &&
359          Desc.hasImplicitDefOfPhysReg(AMDGPU::EXEC);
360 }
361 
362 void AMDGPUMCCodeEmitter::encodeInstruction(const MCInst &MI,
363                                             SmallVectorImpl<char> &CB,
364                                             SmallVectorImpl<MCFixup> &Fixups,
365                                             const MCSubtargetInfo &STI) const {
366   int Opcode = MI.getOpcode();
367   APInt Encoding, Scratch;
368   getBinaryCodeForInstr(MI, Fixups, Encoding, Scratch,  STI);
369   const MCInstrDesc &Desc = MCII.get(MI.getOpcode());
370   unsigned bytes = Desc.getSize();
371 
372   // Set unused op_sel_hi bits to 1 for VOP3P and MAI instructions.
373   // Note that accvgpr_read/write are MAI, have src0, but do not use op_sel.
374   if ((Desc.TSFlags & SIInstrFlags::VOP3P) ||
375       Opcode == AMDGPU::V_ACCVGPR_READ_B32_vi ||
376       Opcode == AMDGPU::V_ACCVGPR_WRITE_B32_vi) {
377     Encoding |= getImplicitOpSelHiEncoding(Opcode);
378   }
379 
380   // GFX10+ v_cmpx opcodes promoted to VOP3 have implied dst=EXEC.
381   // Documentation requires dst to be encoded as EXEC (0x7E),
382   // but it looks like the actual value encoded for dst operand
383   // is ignored by HW. It was decided to define dst as "do not care"
384   // in td files to allow disassembler accept any dst value.
385   // However, dst is encoded as EXEC for compatibility with SP3.
386   if (AMDGPU::isGFX10Plus(STI) && isVCMPX64(Desc)) {
387     assert((Encoding & 0xFF) == 0);
388     Encoding |= MRI.getEncodingValue(AMDGPU::EXEC_LO) &
389                 AMDGPU::HWEncoding::REG_IDX_MASK;
390   }
391 
392   for (unsigned i = 0; i < bytes; i++) {
393     CB.push_back((uint8_t)Encoding.extractBitsAsZExtValue(8, 8 * i));
394   }
395 
396   // NSA encoding.
397   if (AMDGPU::isGFX10Plus(STI) && Desc.TSFlags & SIInstrFlags::MIMG) {
398     int vaddr0 = AMDGPU::getNamedOperandIdx(MI.getOpcode(),
399                                             AMDGPU::OpName::vaddr0);
400     int srsrc = AMDGPU::getNamedOperandIdx(MI.getOpcode(),
401                                            AMDGPU::OpName::srsrc);
402     assert(vaddr0 >= 0 && srsrc > vaddr0);
403     unsigned NumExtraAddrs = srsrc - vaddr0 - 1;
404     unsigned NumPadding = (-NumExtraAddrs) & 3;
405 
406     for (unsigned i = 0; i < NumExtraAddrs; ++i) {
407       getMachineOpValue(MI, MI.getOperand(vaddr0 + 1 + i), Encoding, Fixups,
408                         STI);
409       CB.push_back((uint8_t)Encoding.getLimitedValue());
410     }
411     CB.append(NumPadding, 0);
412   }
413 
414   if ((bytes > 8 && STI.hasFeature(AMDGPU::FeatureVOP3Literal)) ||
415       (bytes > 4 && !STI.hasFeature(AMDGPU::FeatureVOP3Literal)))
416     return;
417 
418   // Do not print literals from SISrc Operands for insts with mandatory literals
419   if (AMDGPU::hasNamedOperand(MI.getOpcode(), AMDGPU::OpName::imm))
420     return;
421 
422   // Check for additional literals
423   for (unsigned i = 0, e = Desc.getNumOperands(); i < e; ++i) {
424 
425     // Check if this operand should be encoded as [SV]Src
426     if (!AMDGPU::isSISrcOperand(Desc, i))
427       continue;
428 
429     // Is this operand a literal immediate?
430     const MCOperand &Op = MI.getOperand(i);
431     auto Enc = getLitEncoding(Op, Desc.operands()[i], STI);
432     if (!Enc || *Enc != 255)
433       continue;
434 
435     // Yes! Encode it
436     int64_t Imm = 0;
437 
438     if (Op.isImm())
439       Imm = Op.getImm();
440     else if (Op.isExpr()) {
441       if (const auto *C = dyn_cast<MCConstantExpr>(Op.getExpr()))
442         Imm = C->getValue();
443     } else // Exprs will be replaced with a fixup value.
444       llvm_unreachable("Must be immediate or expr");
445 
446     if (Desc.operands()[i].OperandType == AMDGPU::OPERAND_REG_IMM_FP64)
447       Imm = Hi_32(Imm);
448 
449     support::endian::write<uint32_t>(CB, Imm, llvm::endianness::little);
450 
451     // Only one literal value allowed
452     break;
453   }
454 }
455 
456 void AMDGPUMCCodeEmitter::getSOPPBrEncoding(const MCInst &MI, unsigned OpNo,
457                                             APInt &Op,
458                                             SmallVectorImpl<MCFixup> &Fixups,
459                                             const MCSubtargetInfo &STI) const {
460   const MCOperand &MO = MI.getOperand(OpNo);
461 
462   if (MO.isExpr()) {
463     const MCExpr *Expr = MO.getExpr();
464     MCFixupKind Kind = (MCFixupKind)AMDGPU::fixup_si_sopp_br;
465     Fixups.push_back(MCFixup::create(0, Expr, Kind, MI.getLoc()));
466     Op = APInt::getZero(96);
467   } else {
468     getMachineOpValue(MI, MO, Op, Fixups, STI);
469   }
470 }
471 
472 void AMDGPUMCCodeEmitter::getSMEMOffsetEncoding(
473     const MCInst &MI, unsigned OpNo, APInt &Op,
474     SmallVectorImpl<MCFixup> &Fixups, const MCSubtargetInfo &STI) const {
475   auto Offset = MI.getOperand(OpNo).getImm();
476   // VI only supports 20-bit unsigned offsets.
477   assert(!AMDGPU::isVI(STI) || isUInt<20>(Offset));
478   Op = Offset;
479 }
480 
481 void AMDGPUMCCodeEmitter::getSDWASrcEncoding(const MCInst &MI, unsigned OpNo,
482                                              APInt &Op,
483                                              SmallVectorImpl<MCFixup> &Fixups,
484                                              const MCSubtargetInfo &STI) const {
485   using namespace AMDGPU::SDWA;
486 
487   uint64_t RegEnc = 0;
488 
489   const MCOperand &MO = MI.getOperand(OpNo);
490 
491   if (MO.isReg()) {
492     unsigned Reg = MO.getReg();
493     RegEnc |= MRI.getEncodingValue(Reg);
494     RegEnc &= SDWA9EncValues::SRC_VGPR_MASK;
495     if (AMDGPU::isSGPR(AMDGPU::mc2PseudoReg(Reg), &MRI)) {
496       RegEnc |= SDWA9EncValues::SRC_SGPR_MASK;
497     }
498     Op = RegEnc;
499     return;
500   } else {
501     const MCInstrDesc &Desc = MCII.get(MI.getOpcode());
502     auto Enc = getLitEncoding(MO, Desc.operands()[OpNo], STI);
503     if (Enc && *Enc != 255) {
504       Op = *Enc | SDWA9EncValues::SRC_SGPR_MASK;
505       return;
506     }
507   }
508 
509   llvm_unreachable("Unsupported operand kind");
510 }
511 
512 void AMDGPUMCCodeEmitter::getSDWAVopcDstEncoding(
513     const MCInst &MI, unsigned OpNo, APInt &Op,
514     SmallVectorImpl<MCFixup> &Fixups, const MCSubtargetInfo &STI) const {
515   using namespace AMDGPU::SDWA;
516 
517   uint64_t RegEnc = 0;
518 
519   const MCOperand &MO = MI.getOperand(OpNo);
520 
521   unsigned Reg = MO.getReg();
522   if (Reg != AMDGPU::VCC && Reg != AMDGPU::VCC_LO) {
523     RegEnc |= MRI.getEncodingValue(Reg);
524     RegEnc &= SDWA9EncValues::VOPC_DST_SGPR_MASK;
525     RegEnc |= SDWA9EncValues::VOPC_DST_VCC_MASK;
526   }
527   Op = RegEnc;
528 }
529 
530 void AMDGPUMCCodeEmitter::getAVOperandEncoding(
531     const MCInst &MI, unsigned OpNo, APInt &Op,
532     SmallVectorImpl<MCFixup> &Fixups, const MCSubtargetInfo &STI) const {
533   unsigned Reg = MI.getOperand(OpNo).getReg();
534   unsigned Enc = MRI.getEncodingValue(Reg);
535   unsigned Idx = Enc & AMDGPU::HWEncoding::REG_IDX_MASK;
536   bool IsVGPROrAGPR = Enc & AMDGPU::HWEncoding::IS_VGPR_OR_AGPR;
537 
538   // VGPR and AGPR have the same encoding, but SrcA and SrcB operands of mfma
539   // instructions use acc[0:1] modifier bits to distinguish. These bits are
540   // encoded as a virtual 9th bit of the register for these operands.
541   bool IsAGPR = false;
542   if (MRI.getRegClass(AMDGPU::AGPR_32RegClassID).contains(Reg) ||
543       MRI.getRegClass(AMDGPU::AReg_64RegClassID).contains(Reg) ||
544       MRI.getRegClass(AMDGPU::AReg_96RegClassID).contains(Reg) ||
545       MRI.getRegClass(AMDGPU::AReg_128RegClassID).contains(Reg) ||
546       MRI.getRegClass(AMDGPU::AReg_160RegClassID).contains(Reg) ||
547       MRI.getRegClass(AMDGPU::AReg_192RegClassID).contains(Reg) ||
548       MRI.getRegClass(AMDGPU::AReg_224RegClassID).contains(Reg) ||
549       MRI.getRegClass(AMDGPU::AReg_256RegClassID).contains(Reg) ||
550       MRI.getRegClass(AMDGPU::AReg_288RegClassID).contains(Reg) ||
551       MRI.getRegClass(AMDGPU::AReg_320RegClassID).contains(Reg) ||
552       MRI.getRegClass(AMDGPU::AReg_352RegClassID).contains(Reg) ||
553       MRI.getRegClass(AMDGPU::AReg_384RegClassID).contains(Reg) ||
554       MRI.getRegClass(AMDGPU::AReg_512RegClassID).contains(Reg) ||
555       MRI.getRegClass(AMDGPU::AGPR_LO16RegClassID).contains(Reg))
556     IsAGPR = true;
557 
558   Op = Idx | (IsVGPROrAGPR << 8) | (IsAGPR << 9);
559 }
560 
561 static bool needsPCRel(const MCExpr *Expr) {
562   switch (Expr->getKind()) {
563   case MCExpr::SymbolRef: {
564     auto *SE = cast<MCSymbolRefExpr>(Expr);
565     MCSymbolRefExpr::VariantKind Kind = SE->getKind();
566     return Kind != MCSymbolRefExpr::VK_AMDGPU_ABS32_LO &&
567            Kind != MCSymbolRefExpr::VK_AMDGPU_ABS32_HI;
568   }
569   case MCExpr::Binary: {
570     auto *BE = cast<MCBinaryExpr>(Expr);
571     if (BE->getOpcode() == MCBinaryExpr::Sub)
572       return false;
573     return needsPCRel(BE->getLHS()) || needsPCRel(BE->getRHS());
574   }
575   case MCExpr::Unary:
576     return needsPCRel(cast<MCUnaryExpr>(Expr)->getSubExpr());
577   case MCExpr::Target:
578   case MCExpr::Constant:
579     return false;
580   }
581   llvm_unreachable("invalid kind");
582 }
583 
584 void AMDGPUMCCodeEmitter::getMachineOpValue(const MCInst &MI,
585                                             const MCOperand &MO, APInt &Op,
586                                             SmallVectorImpl<MCFixup> &Fixups,
587                                             const MCSubtargetInfo &STI) const {
588   if (MO.isReg()){
589     unsigned Enc = MRI.getEncodingValue(MO.getReg());
590     unsigned Idx = Enc & AMDGPU::HWEncoding::REG_IDX_MASK;
591     bool IsVGPR = Enc & AMDGPU::HWEncoding::IS_VGPR_OR_AGPR;
592     Op = Idx | (IsVGPR << 8);
593     return;
594   }
595   unsigned OpNo = &MO - MI.begin();
596   getMachineOpValueCommon(MI, MO, OpNo, Op, Fixups, STI);
597 }
598 
599 void AMDGPUMCCodeEmitter::getMachineOpValueT16(
600     const MCInst &MI, unsigned OpNo, APInt &Op,
601     SmallVectorImpl<MCFixup> &Fixups, const MCSubtargetInfo &STI) const {
602   const MCOperand &MO = MI.getOperand(OpNo);
603   if (MO.isReg()) {
604     unsigned Enc = MRI.getEncodingValue(MO.getReg());
605     unsigned Idx = Enc & AMDGPU::HWEncoding::REG_IDX_MASK;
606     bool IsVGPR = Enc & AMDGPU::HWEncoding::IS_VGPR_OR_AGPR;
607     Op = Idx | (IsVGPR << 8);
608     return;
609   }
610   getMachineOpValueCommon(MI, MO, OpNo, Op, Fixups, STI);
611   // VGPRs include the suffix/op_sel bit in the register encoding, but
612   // immediates and SGPRs include it in src_modifiers. Therefore, copy the
613   // op_sel bit from the src operands into src_modifier operands if Op is
614   // src_modifiers and the corresponding src is a VGPR
615   int SrcMOIdx = -1;
616   assert(OpNo < INT_MAX);
617   if ((int)OpNo == AMDGPU::getNamedOperandIdx(MI.getOpcode(),
618                                               AMDGPU::OpName::src0_modifiers)) {
619     SrcMOIdx = AMDGPU::getNamedOperandIdx(MI.getOpcode(), AMDGPU::OpName::src0);
620     int VDstMOIdx =
621         AMDGPU::getNamedOperandIdx(MI.getOpcode(), AMDGPU::OpName::vdst);
622     if (VDstMOIdx != -1) {
623       auto DstReg = MI.getOperand(VDstMOIdx).getReg();
624       if (AMDGPU::isHi(DstReg, MRI))
625         Op |= SISrcMods::DST_OP_SEL;
626     }
627   } else if ((int)OpNo == AMDGPU::getNamedOperandIdx(
628                               MI.getOpcode(), AMDGPU::OpName::src1_modifiers))
629     SrcMOIdx = AMDGPU::getNamedOperandIdx(MI.getOpcode(), AMDGPU::OpName::src1);
630   else if ((int)OpNo == AMDGPU::getNamedOperandIdx(
631                             MI.getOpcode(), AMDGPU::OpName::src2_modifiers))
632     SrcMOIdx = AMDGPU::getNamedOperandIdx(MI.getOpcode(), AMDGPU::OpName::src2);
633   if (SrcMOIdx == -1)
634     return;
635 
636   const MCOperand &SrcMO = MI.getOperand(SrcMOIdx);
637   if (!SrcMO.isReg())
638     return;
639   auto SrcReg = SrcMO.getReg();
640   if (AMDGPU::isSGPR(SrcReg, &MRI))
641     return;
642   if (AMDGPU::isHi(SrcReg, MRI))
643     Op |= SISrcMods::OP_SEL_0;
644 }
645 
646 void AMDGPUMCCodeEmitter::getMachineOpValueT16Lo128(
647     const MCInst &MI, unsigned OpNo, APInt &Op,
648     SmallVectorImpl<MCFixup> &Fixups, const MCSubtargetInfo &STI) const {
649   const MCOperand &MO = MI.getOperand(OpNo);
650   if (MO.isReg()) {
651     uint16_t Encoding = MRI.getEncodingValue(MO.getReg());
652     unsigned RegIdx = Encoding & AMDGPU::HWEncoding::REG_IDX_MASK;
653     bool IsHi = Encoding & AMDGPU::HWEncoding::IS_HI;
654     bool IsVGPR = Encoding & AMDGPU::HWEncoding::IS_VGPR_OR_AGPR;
655     assert((!IsVGPR || isUInt<7>(RegIdx)) && "VGPR0-VGPR127 expected!");
656     Op = (IsVGPR ? 0x100 : 0) | (IsHi ? 0x80 : 0) | RegIdx;
657     return;
658   }
659   getMachineOpValueCommon(MI, MO, OpNo, Op, Fixups, STI);
660 }
661 
662 void AMDGPUMCCodeEmitter::getMachineOpValueCommon(
663     const MCInst &MI, const MCOperand &MO, unsigned OpNo, APInt &Op,
664     SmallVectorImpl<MCFixup> &Fixups, const MCSubtargetInfo &STI) const {
665   int64_t Val;
666   if (MO.isExpr() && MO.getExpr()->evaluateAsAbsolute(Val)) {
667     Op = Val;
668     return;
669   }
670 
671   if (MO.isExpr() && MO.getExpr()->getKind() != MCExpr::Constant) {
672     // FIXME: If this is expression is PCRel or not should not depend on what
673     // the expression looks like. Given that this is just a general expression,
674     // it should probably be FK_Data_4 and whatever is producing
675     //
676     //    s_add_u32 s2, s2, (extern_const_addrspace+16
677     //
678     // And expecting a PCRel should instead produce
679     //
680     // .Ltmp1:
681     //   s_add_u32 s2, s2, (extern_const_addrspace+16)-.Ltmp1
682     MCFixupKind Kind;
683     if (needsPCRel(MO.getExpr()))
684       Kind = FK_PCRel_4;
685     else
686       Kind = FK_Data_4;
687 
688     const MCInstrDesc &Desc = MCII.get(MI.getOpcode());
689     uint32_t Offset = Desc.getSize();
690     assert(Offset == 4 || Offset == 8);
691 
692     Fixups.push_back(MCFixup::create(Offset, MO.getExpr(), Kind, MI.getLoc()));
693   }
694 
695   const MCInstrDesc &Desc = MCII.get(MI.getOpcode());
696   if (AMDGPU::isSISrcOperand(Desc, OpNo)) {
697     if (auto Enc = getLitEncoding(MO, Desc.operands()[OpNo], STI)) {
698       Op = *Enc;
699       return;
700     }
701   } else if (MO.isImm()) {
702     Op = MO.getImm();
703     return;
704   }
705 
706   llvm_unreachable("Encoding of this operand type is not supported yet.");
707 }
708 
709 #include "AMDGPUGenMCCodeEmitter.inc"
710