xref: /freebsd/contrib/llvm-project/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCCodeEmitter.cpp (revision 1db9f3b21e39176dd5b67cf8ac378633b172463e)
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 getLit16IntEncoding(uint16_t Val, const MCSubtargetInfo &STI) {
120   uint16_t IntImm = getIntInlineImmEncoding(static_cast<int16_t>(Val));
121   return IntImm == 0 ? 255 : IntImm;
122 }
123 
124 static uint32_t getLit16Encoding(uint16_t Val, const MCSubtargetInfo &STI) {
125   uint16_t IntImm = getIntInlineImmEncoding(static_cast<int16_t>(Val));
126   if (IntImm != 0)
127     return IntImm;
128 
129   if (Val == 0x3800) // 0.5
130     return 240;
131 
132   if (Val == 0xB800) // -0.5
133     return 241;
134 
135   if (Val == 0x3C00) // 1.0
136     return 242;
137 
138   if (Val == 0xBC00) // -1.0
139     return 243;
140 
141   if (Val == 0x4000) // 2.0
142     return 244;
143 
144   if (Val == 0xC000) // -2.0
145     return 245;
146 
147   if (Val == 0x4400) // 4.0
148     return 246;
149 
150   if (Val == 0xC400) // -4.0
151     return 247;
152 
153   if (Val == 0x3118 && // 1.0 / (2.0 * pi)
154       STI.hasFeature(AMDGPU::FeatureInv2PiInlineImm))
155     return 248;
156 
157   return 255;
158 }
159 
160 static uint32_t getLit32Encoding(uint32_t Val, const MCSubtargetInfo &STI) {
161   uint32_t IntImm = getIntInlineImmEncoding(static_cast<int32_t>(Val));
162   if (IntImm != 0)
163     return IntImm;
164 
165   if (Val == llvm::bit_cast<uint32_t>(0.5f))
166     return 240;
167 
168   if (Val == llvm::bit_cast<uint32_t>(-0.5f))
169     return 241;
170 
171   if (Val == llvm::bit_cast<uint32_t>(1.0f))
172     return 242;
173 
174   if (Val == llvm::bit_cast<uint32_t>(-1.0f))
175     return 243;
176 
177   if (Val == llvm::bit_cast<uint32_t>(2.0f))
178     return 244;
179 
180   if (Val == llvm::bit_cast<uint32_t>(-2.0f))
181     return 245;
182 
183   if (Val == llvm::bit_cast<uint32_t>(4.0f))
184     return 246;
185 
186   if (Val == llvm::bit_cast<uint32_t>(-4.0f))
187     return 247;
188 
189   if (Val == 0x3e22f983 && // 1.0 / (2.0 * pi)
190       STI.hasFeature(AMDGPU::FeatureInv2PiInlineImm))
191     return 248;
192 
193   return 255;
194 }
195 
196 static uint32_t getLit64Encoding(uint64_t Val, const MCSubtargetInfo &STI) {
197   uint32_t IntImm = getIntInlineImmEncoding(static_cast<int64_t>(Val));
198   if (IntImm != 0)
199     return IntImm;
200 
201   if (Val == llvm::bit_cast<uint64_t>(0.5))
202     return 240;
203 
204   if (Val == llvm::bit_cast<uint64_t>(-0.5))
205     return 241;
206 
207   if (Val == llvm::bit_cast<uint64_t>(1.0))
208     return 242;
209 
210   if (Val == llvm::bit_cast<uint64_t>(-1.0))
211     return 243;
212 
213   if (Val == llvm::bit_cast<uint64_t>(2.0))
214     return 244;
215 
216   if (Val == llvm::bit_cast<uint64_t>(-2.0))
217     return 245;
218 
219   if (Val == llvm::bit_cast<uint64_t>(4.0))
220     return 246;
221 
222   if (Val == llvm::bit_cast<uint64_t>(-4.0))
223     return 247;
224 
225   if (Val == 0x3fc45f306dc9c882 && // 1.0 / (2.0 * pi)
226       STI.hasFeature(AMDGPU::FeatureInv2PiInlineImm))
227     return 248;
228 
229   return 255;
230 }
231 
232 std::optional<uint32_t>
233 AMDGPUMCCodeEmitter::getLitEncoding(const MCOperand &MO,
234                                     const MCOperandInfo &OpInfo,
235                                     const MCSubtargetInfo &STI) const {
236   int64_t Imm;
237   if (MO.isExpr()) {
238     const auto *C = dyn_cast<MCConstantExpr>(MO.getExpr());
239     if (!C)
240       return 255;
241 
242     Imm = C->getValue();
243   } else {
244 
245     assert(!MO.isDFPImm());
246 
247     if (!MO.isImm())
248       return {};
249 
250     Imm = MO.getImm();
251   }
252 
253   switch (OpInfo.OperandType) {
254   case AMDGPU::OPERAND_REG_IMM_INT32:
255   case AMDGPU::OPERAND_REG_IMM_FP32:
256   case AMDGPU::OPERAND_REG_IMM_FP32_DEFERRED:
257   case AMDGPU::OPERAND_REG_INLINE_C_INT32:
258   case AMDGPU::OPERAND_REG_INLINE_C_FP32:
259   case AMDGPU::OPERAND_REG_INLINE_AC_INT32:
260   case AMDGPU::OPERAND_REG_INLINE_AC_FP32:
261   case AMDGPU::OPERAND_REG_IMM_V2INT32:
262   case AMDGPU::OPERAND_REG_IMM_V2FP32:
263   case AMDGPU::OPERAND_REG_INLINE_C_V2INT32:
264   case AMDGPU::OPERAND_REG_INLINE_C_V2FP32:
265   case AMDGPU::OPERAND_INLINE_SPLIT_BARRIER_INT32:
266     return getLit32Encoding(static_cast<uint32_t>(Imm), STI);
267 
268   case AMDGPU::OPERAND_REG_IMM_INT64:
269   case AMDGPU::OPERAND_REG_IMM_FP64:
270   case AMDGPU::OPERAND_REG_INLINE_C_INT64:
271   case AMDGPU::OPERAND_REG_INLINE_C_FP64:
272   case AMDGPU::OPERAND_REG_INLINE_AC_FP64:
273     return getLit64Encoding(static_cast<uint64_t>(Imm), STI);
274 
275   case AMDGPU::OPERAND_REG_IMM_INT16:
276   case AMDGPU::OPERAND_REG_INLINE_C_INT16:
277   case AMDGPU::OPERAND_REG_INLINE_AC_INT16:
278     return getLit16IntEncoding(static_cast<uint16_t>(Imm), STI);
279   case AMDGPU::OPERAND_REG_IMM_FP16:
280   case AMDGPU::OPERAND_REG_IMM_FP16_DEFERRED:
281   case AMDGPU::OPERAND_REG_INLINE_C_FP16:
282   case AMDGPU::OPERAND_REG_INLINE_AC_FP16:
283     // FIXME Is this correct? What do inline immediates do on SI for f16 src
284     // which does not have f16 support?
285     return getLit16Encoding(static_cast<uint16_t>(Imm), STI);
286   case AMDGPU::OPERAND_REG_IMM_V2INT16:
287   case AMDGPU::OPERAND_REG_INLINE_C_V2INT16:
288   case AMDGPU::OPERAND_REG_INLINE_AC_V2INT16:
289     return AMDGPU::getInlineEncodingV2I16(static_cast<uint32_t>(Imm))
290         .value_or(255);
291   case AMDGPU::OPERAND_REG_IMM_V2FP16:
292   case AMDGPU::OPERAND_REG_INLINE_C_V2FP16:
293   case AMDGPU::OPERAND_REG_INLINE_AC_V2FP16:
294     return AMDGPU::getInlineEncodingV2F16(static_cast<uint32_t>(Imm))
295         .value_or(255);
296   case AMDGPU::OPERAND_KIMM32:
297   case AMDGPU::OPERAND_KIMM16:
298     return MO.getImm();
299   default:
300     llvm_unreachable("invalid operand size");
301   }
302 }
303 
304 uint64_t AMDGPUMCCodeEmitter::getImplicitOpSelHiEncoding(int Opcode) const {
305   using namespace AMDGPU::VOP3PEncoding;
306   using namespace AMDGPU::OpName;
307 
308   if (AMDGPU::hasNamedOperand(Opcode, op_sel_hi)) {
309     if (AMDGPU::hasNamedOperand(Opcode, src2))
310       return 0;
311     if (AMDGPU::hasNamedOperand(Opcode, src1))
312       return OP_SEL_HI_2;
313     if (AMDGPU::hasNamedOperand(Opcode, src0))
314       return OP_SEL_HI_1 | OP_SEL_HI_2;
315   }
316   return OP_SEL_HI_0 | OP_SEL_HI_1 | OP_SEL_HI_2;
317 }
318 
319 static bool isVCMPX64(const MCInstrDesc &Desc) {
320   return (Desc.TSFlags & SIInstrFlags::VOP3) &&
321          Desc.hasImplicitDefOfPhysReg(AMDGPU::EXEC);
322 }
323 
324 void AMDGPUMCCodeEmitter::encodeInstruction(const MCInst &MI,
325                                             SmallVectorImpl<char> &CB,
326                                             SmallVectorImpl<MCFixup> &Fixups,
327                                             const MCSubtargetInfo &STI) const {
328   int Opcode = MI.getOpcode();
329   APInt Encoding, Scratch;
330   getBinaryCodeForInstr(MI, Fixups, Encoding, Scratch,  STI);
331   const MCInstrDesc &Desc = MCII.get(MI.getOpcode());
332   unsigned bytes = Desc.getSize();
333 
334   // Set unused op_sel_hi bits to 1 for VOP3P and MAI instructions.
335   // Note that accvgpr_read/write are MAI, have src0, but do not use op_sel.
336   if ((Desc.TSFlags & SIInstrFlags::VOP3P) ||
337       Opcode == AMDGPU::V_ACCVGPR_READ_B32_vi ||
338       Opcode == AMDGPU::V_ACCVGPR_WRITE_B32_vi) {
339     Encoding |= getImplicitOpSelHiEncoding(Opcode);
340   }
341 
342   // GFX10+ v_cmpx opcodes promoted to VOP3 have implied dst=EXEC.
343   // Documentation requires dst to be encoded as EXEC (0x7E),
344   // but it looks like the actual value encoded for dst operand
345   // is ignored by HW. It was decided to define dst as "do not care"
346   // in td files to allow disassembler accept any dst value.
347   // However, dst is encoded as EXEC for compatibility with SP3.
348   if (AMDGPU::isGFX10Plus(STI) && isVCMPX64(Desc)) {
349     assert((Encoding & 0xFF) == 0);
350     Encoding |= MRI.getEncodingValue(AMDGPU::EXEC_LO) &
351                 AMDGPU::HWEncoding::REG_IDX_MASK;
352   }
353 
354   for (unsigned i = 0; i < bytes; i++) {
355     CB.push_back((uint8_t)Encoding.extractBitsAsZExtValue(8, 8 * i));
356   }
357 
358   // NSA encoding.
359   if (AMDGPU::isGFX10Plus(STI) && Desc.TSFlags & SIInstrFlags::MIMG) {
360     int vaddr0 = AMDGPU::getNamedOperandIdx(MI.getOpcode(),
361                                             AMDGPU::OpName::vaddr0);
362     int srsrc = AMDGPU::getNamedOperandIdx(MI.getOpcode(),
363                                            AMDGPU::OpName::srsrc);
364     assert(vaddr0 >= 0 && srsrc > vaddr0);
365     unsigned NumExtraAddrs = srsrc - vaddr0 - 1;
366     unsigned NumPadding = (-NumExtraAddrs) & 3;
367 
368     for (unsigned i = 0; i < NumExtraAddrs; ++i) {
369       getMachineOpValue(MI, MI.getOperand(vaddr0 + 1 + i), Encoding, Fixups,
370                         STI);
371       CB.push_back((uint8_t)Encoding.getLimitedValue());
372     }
373     CB.append(NumPadding, 0);
374   }
375 
376   if ((bytes > 8 && STI.hasFeature(AMDGPU::FeatureVOP3Literal)) ||
377       (bytes > 4 && !STI.hasFeature(AMDGPU::FeatureVOP3Literal)))
378     return;
379 
380   // Do not print literals from SISrc Operands for insts with mandatory literals
381   if (AMDGPU::hasNamedOperand(MI.getOpcode(), AMDGPU::OpName::imm))
382     return;
383 
384   // Check for additional literals
385   for (unsigned i = 0, e = Desc.getNumOperands(); i < e; ++i) {
386 
387     // Check if this operand should be encoded as [SV]Src
388     if (!AMDGPU::isSISrcOperand(Desc, i))
389       continue;
390 
391     // Is this operand a literal immediate?
392     const MCOperand &Op = MI.getOperand(i);
393     auto Enc = getLitEncoding(Op, Desc.operands()[i], STI);
394     if (!Enc || *Enc != 255)
395       continue;
396 
397     // Yes! Encode it
398     int64_t Imm = 0;
399 
400     if (Op.isImm())
401       Imm = Op.getImm();
402     else if (Op.isExpr()) {
403       if (const auto *C = dyn_cast<MCConstantExpr>(Op.getExpr()))
404         Imm = C->getValue();
405 
406     } else if (!Op.isExpr()) // Exprs will be replaced with a fixup value.
407       llvm_unreachable("Must be immediate or expr");
408 
409     if (Desc.operands()[i].OperandType == AMDGPU::OPERAND_REG_IMM_FP64)
410       Imm = Hi_32(Imm);
411 
412     support::endian::write<uint32_t>(CB, Imm, llvm::endianness::little);
413 
414     // Only one literal value allowed
415     break;
416   }
417 }
418 
419 void AMDGPUMCCodeEmitter::getSOPPBrEncoding(const MCInst &MI, unsigned OpNo,
420                                             APInt &Op,
421                                             SmallVectorImpl<MCFixup> &Fixups,
422                                             const MCSubtargetInfo &STI) const {
423   const MCOperand &MO = MI.getOperand(OpNo);
424 
425   if (MO.isExpr()) {
426     const MCExpr *Expr = MO.getExpr();
427     MCFixupKind Kind = (MCFixupKind)AMDGPU::fixup_si_sopp_br;
428     Fixups.push_back(MCFixup::create(0, Expr, Kind, MI.getLoc()));
429     Op = APInt::getZero(96);
430   } else {
431     getMachineOpValue(MI, MO, Op, Fixups, STI);
432   }
433 }
434 
435 void AMDGPUMCCodeEmitter::getSMEMOffsetEncoding(
436     const MCInst &MI, unsigned OpNo, APInt &Op,
437     SmallVectorImpl<MCFixup> &Fixups, const MCSubtargetInfo &STI) const {
438   auto Offset = MI.getOperand(OpNo).getImm();
439   // VI only supports 20-bit unsigned offsets.
440   assert(!AMDGPU::isVI(STI) || isUInt<20>(Offset));
441   Op = Offset;
442 }
443 
444 void AMDGPUMCCodeEmitter::getSDWASrcEncoding(const MCInst &MI, unsigned OpNo,
445                                              APInt &Op,
446                                              SmallVectorImpl<MCFixup> &Fixups,
447                                              const MCSubtargetInfo &STI) const {
448   using namespace AMDGPU::SDWA;
449 
450   uint64_t RegEnc = 0;
451 
452   const MCOperand &MO = MI.getOperand(OpNo);
453 
454   if (MO.isReg()) {
455     unsigned Reg = MO.getReg();
456     RegEnc |= MRI.getEncodingValue(Reg);
457     RegEnc &= SDWA9EncValues::SRC_VGPR_MASK;
458     if (AMDGPU::isSGPR(AMDGPU::mc2PseudoReg(Reg), &MRI)) {
459       RegEnc |= SDWA9EncValues::SRC_SGPR_MASK;
460     }
461     Op = RegEnc;
462     return;
463   } else {
464     const MCInstrDesc &Desc = MCII.get(MI.getOpcode());
465     auto Enc = getLitEncoding(MO, Desc.operands()[OpNo], STI);
466     if (Enc && *Enc != 255) {
467       Op = *Enc | SDWA9EncValues::SRC_SGPR_MASK;
468       return;
469     }
470   }
471 
472   llvm_unreachable("Unsupported operand kind");
473 }
474 
475 void AMDGPUMCCodeEmitter::getSDWAVopcDstEncoding(
476     const MCInst &MI, unsigned OpNo, APInt &Op,
477     SmallVectorImpl<MCFixup> &Fixups, const MCSubtargetInfo &STI) const {
478   using namespace AMDGPU::SDWA;
479 
480   uint64_t RegEnc = 0;
481 
482   const MCOperand &MO = MI.getOperand(OpNo);
483 
484   unsigned Reg = MO.getReg();
485   if (Reg != AMDGPU::VCC && Reg != AMDGPU::VCC_LO) {
486     RegEnc |= MRI.getEncodingValue(Reg);
487     RegEnc &= SDWA9EncValues::VOPC_DST_SGPR_MASK;
488     RegEnc |= SDWA9EncValues::VOPC_DST_VCC_MASK;
489   }
490   Op = RegEnc;
491 }
492 
493 void AMDGPUMCCodeEmitter::getAVOperandEncoding(
494     const MCInst &MI, unsigned OpNo, APInt &Op,
495     SmallVectorImpl<MCFixup> &Fixups, const MCSubtargetInfo &STI) const {
496   unsigned Reg = MI.getOperand(OpNo).getReg();
497   unsigned Enc = MRI.getEncodingValue(Reg);
498   unsigned Idx = Enc & AMDGPU::HWEncoding::REG_IDX_MASK;
499   bool IsVGPROrAGPR = Enc & AMDGPU::HWEncoding::IS_VGPR_OR_AGPR;
500 
501   // VGPR and AGPR have the same encoding, but SrcA and SrcB operands of mfma
502   // instructions use acc[0:1] modifier bits to distinguish. These bits are
503   // encoded as a virtual 9th bit of the register for these operands.
504   bool IsAGPR = false;
505   if (MRI.getRegClass(AMDGPU::AGPR_32RegClassID).contains(Reg) ||
506       MRI.getRegClass(AMDGPU::AReg_64RegClassID).contains(Reg) ||
507       MRI.getRegClass(AMDGPU::AReg_96RegClassID).contains(Reg) ||
508       MRI.getRegClass(AMDGPU::AReg_128RegClassID).contains(Reg) ||
509       MRI.getRegClass(AMDGPU::AReg_160RegClassID).contains(Reg) ||
510       MRI.getRegClass(AMDGPU::AReg_192RegClassID).contains(Reg) ||
511       MRI.getRegClass(AMDGPU::AReg_224RegClassID).contains(Reg) ||
512       MRI.getRegClass(AMDGPU::AReg_256RegClassID).contains(Reg) ||
513       MRI.getRegClass(AMDGPU::AReg_288RegClassID).contains(Reg) ||
514       MRI.getRegClass(AMDGPU::AReg_320RegClassID).contains(Reg) ||
515       MRI.getRegClass(AMDGPU::AReg_352RegClassID).contains(Reg) ||
516       MRI.getRegClass(AMDGPU::AReg_384RegClassID).contains(Reg) ||
517       MRI.getRegClass(AMDGPU::AReg_512RegClassID).contains(Reg) ||
518       MRI.getRegClass(AMDGPU::AGPR_LO16RegClassID).contains(Reg))
519     IsAGPR = true;
520 
521   Op = Idx | (IsVGPROrAGPR << 8) | (IsAGPR << 9);
522 }
523 
524 static bool needsPCRel(const MCExpr *Expr) {
525   switch (Expr->getKind()) {
526   case MCExpr::SymbolRef: {
527     auto *SE = cast<MCSymbolRefExpr>(Expr);
528     MCSymbolRefExpr::VariantKind Kind = SE->getKind();
529     return Kind != MCSymbolRefExpr::VK_AMDGPU_ABS32_LO &&
530            Kind != MCSymbolRefExpr::VK_AMDGPU_ABS32_HI;
531   }
532   case MCExpr::Binary: {
533     auto *BE = cast<MCBinaryExpr>(Expr);
534     if (BE->getOpcode() == MCBinaryExpr::Sub)
535       return false;
536     return needsPCRel(BE->getLHS()) || needsPCRel(BE->getRHS());
537   }
538   case MCExpr::Unary:
539     return needsPCRel(cast<MCUnaryExpr>(Expr)->getSubExpr());
540   case MCExpr::Target:
541   case MCExpr::Constant:
542     return false;
543   }
544   llvm_unreachable("invalid kind");
545 }
546 
547 void AMDGPUMCCodeEmitter::getMachineOpValue(const MCInst &MI,
548                                             const MCOperand &MO, APInt &Op,
549                                             SmallVectorImpl<MCFixup> &Fixups,
550                                             const MCSubtargetInfo &STI) const {
551   if (MO.isReg()){
552     unsigned Enc = MRI.getEncodingValue(MO.getReg());
553     unsigned Idx = Enc & AMDGPU::HWEncoding::REG_IDX_MASK;
554     bool IsVGPR = Enc & AMDGPU::HWEncoding::IS_VGPR_OR_AGPR;
555     Op = Idx | (IsVGPR << 8);
556     return;
557   }
558   unsigned OpNo = &MO - MI.begin();
559   getMachineOpValueCommon(MI, MO, OpNo, Op, Fixups, STI);
560 }
561 
562 void AMDGPUMCCodeEmitter::getMachineOpValueT16(
563     const MCInst &MI, unsigned OpNo, APInt &Op,
564     SmallVectorImpl<MCFixup> &Fixups, const MCSubtargetInfo &STI) const {
565   llvm_unreachable("TODO: Implement getMachineOpValueT16().");
566 }
567 
568 void AMDGPUMCCodeEmitter::getMachineOpValueT16Lo128(
569     const MCInst &MI, unsigned OpNo, APInt &Op,
570     SmallVectorImpl<MCFixup> &Fixups, const MCSubtargetInfo &STI) const {
571   const MCOperand &MO = MI.getOperand(OpNo);
572   if (MO.isReg()) {
573     uint16_t Encoding = MRI.getEncodingValue(MO.getReg());
574     unsigned RegIdx = Encoding & AMDGPU::HWEncoding::REG_IDX_MASK;
575     bool IsHi = Encoding & AMDGPU::HWEncoding::IS_HI;
576     bool IsVGPR = Encoding & AMDGPU::HWEncoding::IS_VGPR_OR_AGPR;
577     assert((!IsVGPR || isUInt<7>(RegIdx)) && "VGPR0-VGPR127 expected!");
578     Op = (IsVGPR ? 0x100 : 0) | (IsHi ? 0x80 : 0) | RegIdx;
579     return;
580   }
581   getMachineOpValueCommon(MI, MO, OpNo, Op, Fixups, STI);
582 }
583 
584 void AMDGPUMCCodeEmitter::getMachineOpValueCommon(
585     const MCInst &MI, const MCOperand &MO, unsigned OpNo, APInt &Op,
586     SmallVectorImpl<MCFixup> &Fixups, const MCSubtargetInfo &STI) const {
587 
588   if (MO.isExpr() && MO.getExpr()->getKind() != MCExpr::Constant) {
589     // FIXME: If this is expression is PCRel or not should not depend on what
590     // the expression looks like. Given that this is just a general expression,
591     // it should probably be FK_Data_4 and whatever is producing
592     //
593     //    s_add_u32 s2, s2, (extern_const_addrspace+16
594     //
595     // And expecting a PCRel should instead produce
596     //
597     // .Ltmp1:
598     //   s_add_u32 s2, s2, (extern_const_addrspace+16)-.Ltmp1
599     MCFixupKind Kind;
600     if (needsPCRel(MO.getExpr()))
601       Kind = FK_PCRel_4;
602     else
603       Kind = FK_Data_4;
604 
605     const MCInstrDesc &Desc = MCII.get(MI.getOpcode());
606     uint32_t Offset = Desc.getSize();
607     assert(Offset == 4 || Offset == 8);
608 
609     Fixups.push_back(MCFixup::create(Offset, MO.getExpr(), Kind, MI.getLoc()));
610   }
611 
612   const MCInstrDesc &Desc = MCII.get(MI.getOpcode());
613   if (AMDGPU::isSISrcOperand(Desc, OpNo)) {
614     if (auto Enc = getLitEncoding(MO, Desc.operands()[OpNo], STI)) {
615       Op = *Enc;
616       return;
617     }
618   } else if (MO.isImm()) {
619     Op = MO.getImm();
620     return;
621   }
622 
623   llvm_unreachable("Encoding of this operand type is not supported yet.");
624 }
625 
626 #include "AMDGPUGenMCCodeEmitter.inc"
627