1 //===-- AMDGPUTargetStreamer.cpp - Mips Target Streamer Methods -----------===//
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 // This file provides AMDGPU specific target streamer methods.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "AMDGPUTargetStreamer.h"
14 #include "AMDGPUPTNote.h"
15 #include "AMDKernelCodeT.h"
16 #include "Utils/AMDGPUBaseInfo.h"
17 #include "Utils/AMDKernelCodeTUtils.h"
18 #include "llvm/BinaryFormat/AMDGPUMetadataVerifier.h"
19 #include "llvm/BinaryFormat/ELF.h"
20 #include "llvm/MC/MCContext.h"
21 #include "llvm/MC/MCELFStreamer.h"
22 #include "llvm/MC/MCSectionELF.h"
23 #include "llvm/Support/AMDGPUMetadata.h"
24 #include "llvm/Support/AMDHSAKernelDescriptor.h"
25 #include "llvm/Support/FormattedStream.h"
26 
27 using namespace llvm;
28 using namespace llvm::AMDGPU;
29 
30 //===----------------------------------------------------------------------===//
31 // AMDGPUTargetStreamer
32 //===----------------------------------------------------------------------===//
33 
34 static void convertIsaVersionV2(uint32_t &Major, uint32_t &Minor,
35                                 uint32_t &Stepping, bool Sramecc, bool Xnack) {
36   if (Major == 9 && Minor == 0) {
37     switch (Stepping) {
38       case 0:
39       case 2:
40       case 4:
41       case 6:
42         if (Xnack)
43           Stepping++;
44     }
45   }
46 }
47 
48 bool AMDGPUTargetStreamer::EmitHSAMetadataV2(StringRef HSAMetadataString) {
49   HSAMD::Metadata HSAMetadata;
50   if (HSAMD::fromString(HSAMetadataString, HSAMetadata))
51     return false;
52   return EmitHSAMetadata(HSAMetadata);
53 }
54 
55 bool AMDGPUTargetStreamer::EmitHSAMetadataV3(StringRef HSAMetadataString) {
56   msgpack::Document HSAMetadataDoc;
57   if (!HSAMetadataDoc.fromYAML(HSAMetadataString))
58     return false;
59   return EmitHSAMetadata(HSAMetadataDoc, false);
60 }
61 
62 StringRef AMDGPUTargetStreamer::getArchNameFromElfMach(unsigned ElfMach) {
63   AMDGPU::GPUKind AK;
64 
65   switch (ElfMach) {
66   default: llvm_unreachable("Unhandled ELF::EF_AMDGPU type");
67   case ELF::EF_AMDGPU_MACH_R600_R600:      AK = GK_R600;    break;
68   case ELF::EF_AMDGPU_MACH_R600_R630:      AK = GK_R630;    break;
69   case ELF::EF_AMDGPU_MACH_R600_RS880:     AK = GK_RS880;   break;
70   case ELF::EF_AMDGPU_MACH_R600_RV670:     AK = GK_RV670;   break;
71   case ELF::EF_AMDGPU_MACH_R600_RV710:     AK = GK_RV710;   break;
72   case ELF::EF_AMDGPU_MACH_R600_RV730:     AK = GK_RV730;   break;
73   case ELF::EF_AMDGPU_MACH_R600_RV770:     AK = GK_RV770;   break;
74   case ELF::EF_AMDGPU_MACH_R600_CEDAR:     AK = GK_CEDAR;   break;
75   case ELF::EF_AMDGPU_MACH_R600_CYPRESS:   AK = GK_CYPRESS; break;
76   case ELF::EF_AMDGPU_MACH_R600_JUNIPER:   AK = GK_JUNIPER; break;
77   case ELF::EF_AMDGPU_MACH_R600_REDWOOD:   AK = GK_REDWOOD; break;
78   case ELF::EF_AMDGPU_MACH_R600_SUMO:      AK = GK_SUMO;    break;
79   case ELF::EF_AMDGPU_MACH_R600_BARTS:     AK = GK_BARTS;   break;
80   case ELF::EF_AMDGPU_MACH_R600_CAICOS:    AK = GK_CAICOS;  break;
81   case ELF::EF_AMDGPU_MACH_R600_CAYMAN:    AK = GK_CAYMAN;  break;
82   case ELF::EF_AMDGPU_MACH_R600_TURKS:     AK = GK_TURKS;   break;
83   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX600:  AK = GK_GFX600;  break;
84   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX601:  AK = GK_GFX601;  break;
85   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX602:  AK = GK_GFX602;  break;
86   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX700:  AK = GK_GFX700;  break;
87   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX701:  AK = GK_GFX701;  break;
88   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX702:  AK = GK_GFX702;  break;
89   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX703:  AK = GK_GFX703;  break;
90   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX704:  AK = GK_GFX704;  break;
91   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX705:  AK = GK_GFX705;  break;
92   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX801:  AK = GK_GFX801;  break;
93   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX802:  AK = GK_GFX802;  break;
94   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX803:  AK = GK_GFX803;  break;
95   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX805:  AK = GK_GFX805;  break;
96   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX810:  AK = GK_GFX810;  break;
97   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX900:  AK = GK_GFX900;  break;
98   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX902:  AK = GK_GFX902;  break;
99   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX904:  AK = GK_GFX904;  break;
100   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX906:  AK = GK_GFX906;  break;
101   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX908:  AK = GK_GFX908;  break;
102   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX909:  AK = GK_GFX909;  break;
103   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX90A:  AK = GK_GFX90A;  break;
104   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX90C:  AK = GK_GFX90C;  break;
105   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1010: AK = GK_GFX1010; break;
106   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1011: AK = GK_GFX1011; break;
107   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1012: AK = GK_GFX1012; break;
108   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1013: AK = GK_GFX1013; break;
109   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1030: AK = GK_GFX1030; break;
110   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1031: AK = GK_GFX1031; break;
111   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1032: AK = GK_GFX1032; break;
112   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1033: AK = GK_GFX1033; break;
113   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1034: AK = GK_GFX1034; break;
114   case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1035: AK = GK_GFX1035; break;
115   case ELF::EF_AMDGPU_MACH_NONE:           AK = GK_NONE;    break;
116   }
117 
118   StringRef GPUName = getArchNameAMDGCN(AK);
119   if (GPUName != "")
120     return GPUName;
121   return getArchNameR600(AK);
122 }
123 
124 unsigned AMDGPUTargetStreamer::getElfMach(StringRef GPU) {
125   AMDGPU::GPUKind AK = parseArchAMDGCN(GPU);
126   if (AK == AMDGPU::GPUKind::GK_NONE)
127     AK = parseArchR600(GPU);
128 
129   switch (AK) {
130   case GK_R600:    return ELF::EF_AMDGPU_MACH_R600_R600;
131   case GK_R630:    return ELF::EF_AMDGPU_MACH_R600_R630;
132   case GK_RS880:   return ELF::EF_AMDGPU_MACH_R600_RS880;
133   case GK_RV670:   return ELF::EF_AMDGPU_MACH_R600_RV670;
134   case GK_RV710:   return ELF::EF_AMDGPU_MACH_R600_RV710;
135   case GK_RV730:   return ELF::EF_AMDGPU_MACH_R600_RV730;
136   case GK_RV770:   return ELF::EF_AMDGPU_MACH_R600_RV770;
137   case GK_CEDAR:   return ELF::EF_AMDGPU_MACH_R600_CEDAR;
138   case GK_CYPRESS: return ELF::EF_AMDGPU_MACH_R600_CYPRESS;
139   case GK_JUNIPER: return ELF::EF_AMDGPU_MACH_R600_JUNIPER;
140   case GK_REDWOOD: return ELF::EF_AMDGPU_MACH_R600_REDWOOD;
141   case GK_SUMO:    return ELF::EF_AMDGPU_MACH_R600_SUMO;
142   case GK_BARTS:   return ELF::EF_AMDGPU_MACH_R600_BARTS;
143   case GK_CAICOS:  return ELF::EF_AMDGPU_MACH_R600_CAICOS;
144   case GK_CAYMAN:  return ELF::EF_AMDGPU_MACH_R600_CAYMAN;
145   case GK_TURKS:   return ELF::EF_AMDGPU_MACH_R600_TURKS;
146   case GK_GFX600:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX600;
147   case GK_GFX601:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX601;
148   case GK_GFX602:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX602;
149   case GK_GFX700:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX700;
150   case GK_GFX701:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX701;
151   case GK_GFX702:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX702;
152   case GK_GFX703:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX703;
153   case GK_GFX704:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX704;
154   case GK_GFX705:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX705;
155   case GK_GFX801:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX801;
156   case GK_GFX802:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX802;
157   case GK_GFX803:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX803;
158   case GK_GFX805:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX805;
159   case GK_GFX810:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX810;
160   case GK_GFX900:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX900;
161   case GK_GFX902:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX902;
162   case GK_GFX904:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX904;
163   case GK_GFX906:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX906;
164   case GK_GFX908:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX908;
165   case GK_GFX909:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX909;
166   case GK_GFX90A:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX90A;
167   case GK_GFX90C:  return ELF::EF_AMDGPU_MACH_AMDGCN_GFX90C;
168   case GK_GFX1010: return ELF::EF_AMDGPU_MACH_AMDGCN_GFX1010;
169   case GK_GFX1011: return ELF::EF_AMDGPU_MACH_AMDGCN_GFX1011;
170   case GK_GFX1012: return ELF::EF_AMDGPU_MACH_AMDGCN_GFX1012;
171   case GK_GFX1013: return ELF::EF_AMDGPU_MACH_AMDGCN_GFX1013;
172   case GK_GFX1030: return ELF::EF_AMDGPU_MACH_AMDGCN_GFX1030;
173   case GK_GFX1031: return ELF::EF_AMDGPU_MACH_AMDGCN_GFX1031;
174   case GK_GFX1032: return ELF::EF_AMDGPU_MACH_AMDGCN_GFX1032;
175   case GK_GFX1033: return ELF::EF_AMDGPU_MACH_AMDGCN_GFX1033;
176   case GK_GFX1034: return ELF::EF_AMDGPU_MACH_AMDGCN_GFX1034;
177   case GK_GFX1035: return ELF::EF_AMDGPU_MACH_AMDGCN_GFX1035;
178   case GK_NONE:    return ELF::EF_AMDGPU_MACH_NONE;
179   }
180 
181   llvm_unreachable("unknown GPU");
182 }
183 
184 //===----------------------------------------------------------------------===//
185 // AMDGPUTargetAsmStreamer
186 //===----------------------------------------------------------------------===//
187 
188 AMDGPUTargetAsmStreamer::AMDGPUTargetAsmStreamer(MCStreamer &S,
189                                                  formatted_raw_ostream &OS)
190     : AMDGPUTargetStreamer(S), OS(OS) { }
191 
192 // A hook for emitting stuff at the end.
193 // We use it for emitting the accumulated PAL metadata as directives.
194 // The PAL metadata is reset after it is emitted.
195 void AMDGPUTargetAsmStreamer::finish() {
196   std::string S;
197   getPALMetadata()->toString(S);
198   OS << S;
199 
200   // Reset the pal metadata so its data will not affect a compilation that
201   // reuses this object.
202   getPALMetadata()->reset();
203 }
204 
205 void AMDGPUTargetAsmStreamer::EmitDirectiveAMDGCNTarget() {
206   OS << "\t.amdgcn_target \"" << getTargetID()->toString() << "\"\n";
207 }
208 
209 void AMDGPUTargetAsmStreamer::EmitDirectiveHSACodeObjectVersion(
210     uint32_t Major, uint32_t Minor) {
211   OS << "\t.hsa_code_object_version " <<
212         Twine(Major) << "," << Twine(Minor) << '\n';
213 }
214 
215 void
216 AMDGPUTargetAsmStreamer::EmitDirectiveHSACodeObjectISAV2(uint32_t Major,
217                                                          uint32_t Minor,
218                                                          uint32_t Stepping,
219                                                          StringRef VendorName,
220                                                          StringRef ArchName) {
221   convertIsaVersionV2(Major, Minor, Stepping, TargetID->isSramEccOnOrAny(), TargetID->isXnackOnOrAny());
222   OS << "\t.hsa_code_object_isa " << Twine(Major) << "," << Twine(Minor) << ","
223      << Twine(Stepping) << ",\"" << VendorName << "\",\"" << ArchName << "\"\n";
224 }
225 
226 void
227 AMDGPUTargetAsmStreamer::EmitAMDKernelCodeT(const amd_kernel_code_t &Header) {
228   OS << "\t.amd_kernel_code_t\n";
229   dumpAmdKernelCode(&Header, OS, "\t\t");
230   OS << "\t.end_amd_kernel_code_t\n";
231 }
232 
233 void AMDGPUTargetAsmStreamer::EmitAMDGPUSymbolType(StringRef SymbolName,
234                                                    unsigned Type) {
235   switch (Type) {
236     default: llvm_unreachable("Invalid AMDGPU symbol type");
237     case ELF::STT_AMDGPU_HSA_KERNEL:
238       OS << "\t.amdgpu_hsa_kernel " << SymbolName << '\n' ;
239       break;
240   }
241 }
242 
243 void AMDGPUTargetAsmStreamer::emitAMDGPULDS(MCSymbol *Symbol, unsigned Size,
244                                             Align Alignment) {
245   OS << "\t.amdgpu_lds " << Symbol->getName() << ", " << Size << ", "
246      << Alignment.value() << '\n';
247 }
248 
249 bool AMDGPUTargetAsmStreamer::EmitISAVersion() {
250   OS << "\t.amd_amdgpu_isa \"" << getTargetID()->toString() << "\"\n";
251   return true;
252 }
253 
254 bool AMDGPUTargetAsmStreamer::EmitHSAMetadata(
255     const AMDGPU::HSAMD::Metadata &HSAMetadata) {
256   std::string HSAMetadataString;
257   if (HSAMD::toString(HSAMetadata, HSAMetadataString))
258     return false;
259 
260   OS << '\t' << HSAMD::AssemblerDirectiveBegin << '\n';
261   OS << HSAMetadataString << '\n';
262   OS << '\t' << HSAMD::AssemblerDirectiveEnd << '\n';
263   return true;
264 }
265 
266 bool AMDGPUTargetAsmStreamer::EmitHSAMetadata(
267     msgpack::Document &HSAMetadataDoc, bool Strict) {
268   HSAMD::V3::MetadataVerifier Verifier(Strict);
269   if (!Verifier.verify(HSAMetadataDoc.getRoot()))
270     return false;
271 
272   std::string HSAMetadataString;
273   raw_string_ostream StrOS(HSAMetadataString);
274   HSAMetadataDoc.toYAML(StrOS);
275 
276   OS << '\t' << HSAMD::V3::AssemblerDirectiveBegin << '\n';
277   OS << StrOS.str() << '\n';
278   OS << '\t' << HSAMD::V3::AssemblerDirectiveEnd << '\n';
279   return true;
280 }
281 
282 bool AMDGPUTargetAsmStreamer::EmitCodeEnd(const MCSubtargetInfo &STI) {
283   const uint32_t Encoded_s_code_end = 0xbf9f0000;
284   const uint32_t Encoded_s_nop = 0xbf800000;
285   uint32_t Encoded_pad = Encoded_s_code_end;
286 
287   // Instruction cache line size in bytes.
288   const unsigned Log2CacheLineSize = 6;
289   const unsigned CacheLineSize = 1u << Log2CacheLineSize;
290 
291   // Extra padding amount in bytes to support prefetch mode 3.
292   unsigned FillSize = 3 * CacheLineSize;
293 
294   if (AMDGPU::isGFX90A(STI)) {
295     Encoded_pad = Encoded_s_nop;
296     FillSize = 16 * CacheLineSize;
297   }
298 
299   OS << "\t.p2alignl " << Log2CacheLineSize << ", " << Encoded_pad << '\n';
300   OS << "\t.fill " << (FillSize / 4) << ", 4, " << Encoded_pad << '\n';
301   return true;
302 }
303 
304 void AMDGPUTargetAsmStreamer::EmitAmdhsaKernelDescriptor(
305     const MCSubtargetInfo &STI, StringRef KernelName,
306     const amdhsa::kernel_descriptor_t &KD, uint64_t NextVGPR, uint64_t NextSGPR,
307     bool ReserveVCC, bool ReserveFlatScr) {
308   IsaVersion IVersion = getIsaVersion(STI.getCPU());
309 
310   OS << "\t.amdhsa_kernel " << KernelName << '\n';
311 
312 #define PRINT_FIELD(STREAM, DIRECTIVE, KERNEL_DESC, MEMBER_NAME, FIELD_NAME)   \
313   STREAM << "\t\t" << DIRECTIVE << " "                                         \
314          << AMDHSA_BITS_GET(KERNEL_DESC.MEMBER_NAME, FIELD_NAME) << '\n';
315 
316   OS << "\t\t.amdhsa_group_segment_fixed_size " << KD.group_segment_fixed_size
317      << '\n';
318   OS << "\t\t.amdhsa_private_segment_fixed_size "
319      << KD.private_segment_fixed_size << '\n';
320   OS << "\t\t.amdhsa_kernarg_size " << KD.kernarg_size << '\n';
321 
322   PRINT_FIELD(OS, ".amdhsa_user_sgpr_count", KD,
323               compute_pgm_rsrc2,
324               amdhsa::COMPUTE_PGM_RSRC2_USER_SGPR_COUNT);
325 
326   if (!hasArchitectedFlatScratch(STI))
327     PRINT_FIELD(
328         OS, ".amdhsa_user_sgpr_private_segment_buffer", KD,
329         kernel_code_properties,
330         amdhsa::KERNEL_CODE_PROPERTY_ENABLE_SGPR_PRIVATE_SEGMENT_BUFFER);
331   PRINT_FIELD(OS, ".amdhsa_user_sgpr_dispatch_ptr", KD,
332               kernel_code_properties,
333               amdhsa::KERNEL_CODE_PROPERTY_ENABLE_SGPR_DISPATCH_PTR);
334   PRINT_FIELD(OS, ".amdhsa_user_sgpr_queue_ptr", KD,
335               kernel_code_properties,
336               amdhsa::KERNEL_CODE_PROPERTY_ENABLE_SGPR_QUEUE_PTR);
337   PRINT_FIELD(OS, ".amdhsa_user_sgpr_kernarg_segment_ptr", KD,
338               kernel_code_properties,
339               amdhsa::KERNEL_CODE_PROPERTY_ENABLE_SGPR_KERNARG_SEGMENT_PTR);
340   PRINT_FIELD(OS, ".amdhsa_user_sgpr_dispatch_id", KD,
341               kernel_code_properties,
342               amdhsa::KERNEL_CODE_PROPERTY_ENABLE_SGPR_DISPATCH_ID);
343   if (!hasArchitectedFlatScratch(STI))
344     PRINT_FIELD(OS, ".amdhsa_user_sgpr_flat_scratch_init", KD,
345                 kernel_code_properties,
346                 amdhsa::KERNEL_CODE_PROPERTY_ENABLE_SGPR_FLAT_SCRATCH_INIT);
347   PRINT_FIELD(OS, ".amdhsa_user_sgpr_private_segment_size", KD,
348               kernel_code_properties,
349               amdhsa::KERNEL_CODE_PROPERTY_ENABLE_SGPR_PRIVATE_SEGMENT_SIZE);
350   if (IVersion.Major >= 10)
351     PRINT_FIELD(OS, ".amdhsa_wavefront_size32", KD,
352                 kernel_code_properties,
353                 amdhsa::KERNEL_CODE_PROPERTY_ENABLE_WAVEFRONT_SIZE32);
354   PRINT_FIELD(OS,
355               (hasArchitectedFlatScratch(STI)
356                    ? ".amdhsa_enable_private_segment"
357                    : ".amdhsa_system_sgpr_private_segment_wavefront_offset"),
358               KD, compute_pgm_rsrc2,
359               amdhsa::COMPUTE_PGM_RSRC2_ENABLE_PRIVATE_SEGMENT);
360   PRINT_FIELD(OS, ".amdhsa_system_sgpr_workgroup_id_x", KD,
361               compute_pgm_rsrc2,
362               amdhsa::COMPUTE_PGM_RSRC2_ENABLE_SGPR_WORKGROUP_ID_X);
363   PRINT_FIELD(OS, ".amdhsa_system_sgpr_workgroup_id_y", KD,
364               compute_pgm_rsrc2,
365               amdhsa::COMPUTE_PGM_RSRC2_ENABLE_SGPR_WORKGROUP_ID_Y);
366   PRINT_FIELD(OS, ".amdhsa_system_sgpr_workgroup_id_z", KD,
367               compute_pgm_rsrc2,
368               amdhsa::COMPUTE_PGM_RSRC2_ENABLE_SGPR_WORKGROUP_ID_Z);
369   PRINT_FIELD(OS, ".amdhsa_system_sgpr_workgroup_info", KD,
370               compute_pgm_rsrc2,
371               amdhsa::COMPUTE_PGM_RSRC2_ENABLE_SGPR_WORKGROUP_INFO);
372   PRINT_FIELD(OS, ".amdhsa_system_vgpr_workitem_id", KD,
373               compute_pgm_rsrc2,
374               amdhsa::COMPUTE_PGM_RSRC2_ENABLE_VGPR_WORKITEM_ID);
375 
376   // These directives are required.
377   OS << "\t\t.amdhsa_next_free_vgpr " << NextVGPR << '\n';
378   OS << "\t\t.amdhsa_next_free_sgpr " << NextSGPR << '\n';
379 
380   if (AMDGPU::isGFX90A(STI))
381     OS << "\t\t.amdhsa_accum_offset " <<
382       (AMDHSA_BITS_GET(KD.compute_pgm_rsrc3,
383                        amdhsa::COMPUTE_PGM_RSRC3_GFX90A_ACCUM_OFFSET) + 1) * 4
384       << '\n';
385 
386   if (!ReserveVCC)
387     OS << "\t\t.amdhsa_reserve_vcc " << ReserveVCC << '\n';
388   if (IVersion.Major >= 7 && !ReserveFlatScr && !hasArchitectedFlatScratch(STI))
389     OS << "\t\t.amdhsa_reserve_flat_scratch " << ReserveFlatScr << '\n';
390 
391   if (Optional<uint8_t> HsaAbiVer = getHsaAbiVersion(&STI)) {
392     switch (*HsaAbiVer) {
393     default:
394       break;
395     case ELF::ELFABIVERSION_AMDGPU_HSA_V2:
396       break;
397     case ELF::ELFABIVERSION_AMDGPU_HSA_V3:
398     case ELF::ELFABIVERSION_AMDGPU_HSA_V4:
399       if (getTargetID()->isXnackSupported())
400         OS << "\t\t.amdhsa_reserve_xnack_mask " << getTargetID()->isXnackOnOrAny() << '\n';
401       break;
402     }
403   }
404 
405   PRINT_FIELD(OS, ".amdhsa_float_round_mode_32", KD,
406               compute_pgm_rsrc1,
407               amdhsa::COMPUTE_PGM_RSRC1_FLOAT_ROUND_MODE_32);
408   PRINT_FIELD(OS, ".amdhsa_float_round_mode_16_64", KD,
409               compute_pgm_rsrc1,
410               amdhsa::COMPUTE_PGM_RSRC1_FLOAT_ROUND_MODE_16_64);
411   PRINT_FIELD(OS, ".amdhsa_float_denorm_mode_32", KD,
412               compute_pgm_rsrc1,
413               amdhsa::COMPUTE_PGM_RSRC1_FLOAT_DENORM_MODE_32);
414   PRINT_FIELD(OS, ".amdhsa_float_denorm_mode_16_64", KD,
415               compute_pgm_rsrc1,
416               amdhsa::COMPUTE_PGM_RSRC1_FLOAT_DENORM_MODE_16_64);
417   PRINT_FIELD(OS, ".amdhsa_dx10_clamp", KD,
418               compute_pgm_rsrc1,
419               amdhsa::COMPUTE_PGM_RSRC1_ENABLE_DX10_CLAMP);
420   PRINT_FIELD(OS, ".amdhsa_ieee_mode", KD,
421               compute_pgm_rsrc1,
422               amdhsa::COMPUTE_PGM_RSRC1_ENABLE_IEEE_MODE);
423   if (IVersion.Major >= 9)
424     PRINT_FIELD(OS, ".amdhsa_fp16_overflow", KD,
425                 compute_pgm_rsrc1,
426                 amdhsa::COMPUTE_PGM_RSRC1_FP16_OVFL);
427   if (AMDGPU::isGFX90A(STI))
428     PRINT_FIELD(OS, ".amdhsa_tg_split", KD,
429                 compute_pgm_rsrc3,
430                 amdhsa::COMPUTE_PGM_RSRC3_GFX90A_TG_SPLIT);
431   if (IVersion.Major >= 10) {
432     PRINT_FIELD(OS, ".amdhsa_workgroup_processor_mode", KD,
433                 compute_pgm_rsrc1,
434                 amdhsa::COMPUTE_PGM_RSRC1_WGP_MODE);
435     PRINT_FIELD(OS, ".amdhsa_memory_ordered", KD,
436                 compute_pgm_rsrc1,
437                 amdhsa::COMPUTE_PGM_RSRC1_MEM_ORDERED);
438     PRINT_FIELD(OS, ".amdhsa_forward_progress", KD,
439                 compute_pgm_rsrc1,
440                 amdhsa::COMPUTE_PGM_RSRC1_FWD_PROGRESS);
441   }
442   PRINT_FIELD(
443       OS, ".amdhsa_exception_fp_ieee_invalid_op", KD,
444       compute_pgm_rsrc2,
445       amdhsa::COMPUTE_PGM_RSRC2_ENABLE_EXCEPTION_IEEE_754_FP_INVALID_OPERATION);
446   PRINT_FIELD(OS, ".amdhsa_exception_fp_denorm_src", KD,
447               compute_pgm_rsrc2,
448               amdhsa::COMPUTE_PGM_RSRC2_ENABLE_EXCEPTION_FP_DENORMAL_SOURCE);
449   PRINT_FIELD(
450       OS, ".amdhsa_exception_fp_ieee_div_zero", KD,
451       compute_pgm_rsrc2,
452       amdhsa::COMPUTE_PGM_RSRC2_ENABLE_EXCEPTION_IEEE_754_FP_DIVISION_BY_ZERO);
453   PRINT_FIELD(OS, ".amdhsa_exception_fp_ieee_overflow", KD,
454               compute_pgm_rsrc2,
455               amdhsa::COMPUTE_PGM_RSRC2_ENABLE_EXCEPTION_IEEE_754_FP_OVERFLOW);
456   PRINT_FIELD(OS, ".amdhsa_exception_fp_ieee_underflow", KD,
457               compute_pgm_rsrc2,
458               amdhsa::COMPUTE_PGM_RSRC2_ENABLE_EXCEPTION_IEEE_754_FP_UNDERFLOW);
459   PRINT_FIELD(OS, ".amdhsa_exception_fp_ieee_inexact", KD,
460               compute_pgm_rsrc2,
461               amdhsa::COMPUTE_PGM_RSRC2_ENABLE_EXCEPTION_IEEE_754_FP_INEXACT);
462   PRINT_FIELD(OS, ".amdhsa_exception_int_div_zero", KD,
463               compute_pgm_rsrc2,
464               amdhsa::COMPUTE_PGM_RSRC2_ENABLE_EXCEPTION_INT_DIVIDE_BY_ZERO);
465 #undef PRINT_FIELD
466 
467   OS << "\t.end_amdhsa_kernel\n";
468 }
469 
470 //===----------------------------------------------------------------------===//
471 // AMDGPUTargetELFStreamer
472 //===----------------------------------------------------------------------===//
473 
474 AMDGPUTargetELFStreamer::AMDGPUTargetELFStreamer(MCStreamer &S,
475                                                  const MCSubtargetInfo &STI)
476     : AMDGPUTargetStreamer(S), STI(STI), Streamer(S) {}
477 
478 MCELFStreamer &AMDGPUTargetELFStreamer::getStreamer() {
479   return static_cast<MCELFStreamer &>(Streamer);
480 }
481 
482 // A hook for emitting stuff at the end.
483 // We use it for emitting the accumulated PAL metadata as a .note record.
484 // The PAL metadata is reset after it is emitted.
485 void AMDGPUTargetELFStreamer::finish() {
486   MCAssembler &MCA = getStreamer().getAssembler();
487   MCA.setELFHeaderEFlags(getEFlags());
488 
489   std::string Blob;
490   const char *Vendor = getPALMetadata()->getVendor();
491   unsigned Type = getPALMetadata()->getType();
492   getPALMetadata()->toBlob(Type, Blob);
493   if (Blob.empty())
494     return;
495   EmitNote(Vendor, MCConstantExpr::create(Blob.size(), getContext()), Type,
496            [&](MCELFStreamer &OS) { OS.emitBytes(Blob); });
497 
498   // Reset the pal metadata so its data will not affect a compilation that
499   // reuses this object.
500   getPALMetadata()->reset();
501 }
502 
503 void AMDGPUTargetELFStreamer::EmitNote(
504     StringRef Name, const MCExpr *DescSZ, unsigned NoteType,
505     function_ref<void(MCELFStreamer &)> EmitDesc) {
506   auto &S = getStreamer();
507   auto &Context = S.getContext();
508 
509   auto NameSZ = Name.size() + 1;
510 
511   unsigned NoteFlags = 0;
512   // TODO Apparently, this is currently needed for OpenCL as mentioned in
513   // https://reviews.llvm.org/D74995
514   if (STI.getTargetTriple().getOS() == Triple::AMDHSA)
515     NoteFlags = ELF::SHF_ALLOC;
516 
517   S.PushSection();
518   S.SwitchSection(
519       Context.getELFSection(ElfNote::SectionName, ELF::SHT_NOTE, NoteFlags));
520   S.emitInt32(NameSZ);                                        // namesz
521   S.emitValue(DescSZ, 4);                                     // descz
522   S.emitInt32(NoteType);                                      // type
523   S.emitBytes(Name);                                          // name
524   S.emitValueToAlignment(4, 0, 1, 0);                         // padding 0
525   EmitDesc(S);                                                // desc
526   S.emitValueToAlignment(4, 0, 1, 0);                         // padding 0
527   S.PopSection();
528 }
529 
530 unsigned AMDGPUTargetELFStreamer::getEFlags() {
531   switch (STI.getTargetTriple().getArch()) {
532   default:
533     llvm_unreachable("Unsupported Arch");
534   case Triple::r600:
535     return getEFlagsR600();
536   case Triple::amdgcn:
537     return getEFlagsAMDGCN();
538   }
539 }
540 
541 unsigned AMDGPUTargetELFStreamer::getEFlagsR600() {
542   assert(STI.getTargetTriple().getArch() == Triple::r600);
543 
544   return getElfMach(STI.getCPU());
545 }
546 
547 unsigned AMDGPUTargetELFStreamer::getEFlagsAMDGCN() {
548   assert(STI.getTargetTriple().getArch() == Triple::amdgcn);
549 
550   switch (STI.getTargetTriple().getOS()) {
551   default:
552     // TODO: Why are some tests have "mingw" listed as OS?
553     // llvm_unreachable("Unsupported OS");
554   case Triple::UnknownOS:
555     return getEFlagsUnknownOS();
556   case Triple::AMDHSA:
557     return getEFlagsAMDHSA();
558   case Triple::AMDPAL:
559     return getEFlagsAMDPAL();
560   case Triple::Mesa3D:
561     return getEFlagsMesa3D();
562   }
563 }
564 
565 unsigned AMDGPUTargetELFStreamer::getEFlagsUnknownOS() {
566   // TODO: Why are some tests have "mingw" listed as OS?
567   // assert(STI.getTargetTriple().getOS() == Triple::UnknownOS);
568 
569   return getEFlagsV3();
570 }
571 
572 unsigned AMDGPUTargetELFStreamer::getEFlagsAMDHSA() {
573   assert(STI.getTargetTriple().getOS() == Triple::AMDHSA);
574 
575   if (Optional<uint8_t> HsaAbiVer = getHsaAbiVersion(&STI)) {
576     switch (*HsaAbiVer) {
577     case ELF::ELFABIVERSION_AMDGPU_HSA_V2:
578     case ELF::ELFABIVERSION_AMDGPU_HSA_V3:
579       return getEFlagsV3();
580     case ELF::ELFABIVERSION_AMDGPU_HSA_V4:
581       return getEFlagsV4();
582     }
583   }
584 
585   llvm_unreachable("HSA OS ABI Version identification must be defined");
586 }
587 
588 unsigned AMDGPUTargetELFStreamer::getEFlagsAMDPAL() {
589   assert(STI.getTargetTriple().getOS() == Triple::AMDPAL);
590 
591   return getEFlagsV3();
592 }
593 
594 unsigned AMDGPUTargetELFStreamer::getEFlagsMesa3D() {
595   assert(STI.getTargetTriple().getOS() == Triple::Mesa3D);
596 
597   return getEFlagsV3();
598 }
599 
600 unsigned AMDGPUTargetELFStreamer::getEFlagsV3() {
601   unsigned EFlagsV3 = 0;
602 
603   // mach.
604   EFlagsV3 |= getElfMach(STI.getCPU());
605 
606   // xnack.
607   if (getTargetID()->isXnackOnOrAny())
608     EFlagsV3 |= ELF::EF_AMDGPU_FEATURE_XNACK_V3;
609   // sramecc.
610   if (getTargetID()->isSramEccOnOrAny())
611     EFlagsV3 |= ELF::EF_AMDGPU_FEATURE_SRAMECC_V3;
612 
613   return EFlagsV3;
614 }
615 
616 unsigned AMDGPUTargetELFStreamer::getEFlagsV4() {
617   unsigned EFlagsV4 = 0;
618 
619   // mach.
620   EFlagsV4 |= getElfMach(STI.getCPU());
621 
622   // xnack.
623   switch (getTargetID()->getXnackSetting()) {
624   case AMDGPU::IsaInfo::TargetIDSetting::Unsupported:
625     EFlagsV4 |= ELF::EF_AMDGPU_FEATURE_XNACK_UNSUPPORTED_V4;
626     break;
627   case AMDGPU::IsaInfo::TargetIDSetting::Any:
628     EFlagsV4 |= ELF::EF_AMDGPU_FEATURE_XNACK_ANY_V4;
629     break;
630   case AMDGPU::IsaInfo::TargetIDSetting::Off:
631     EFlagsV4 |= ELF::EF_AMDGPU_FEATURE_XNACK_OFF_V4;
632     break;
633   case AMDGPU::IsaInfo::TargetIDSetting::On:
634     EFlagsV4 |= ELF::EF_AMDGPU_FEATURE_XNACK_ON_V4;
635     break;
636   }
637   // sramecc.
638   switch (getTargetID()->getSramEccSetting()) {
639   case AMDGPU::IsaInfo::TargetIDSetting::Unsupported:
640     EFlagsV4 |= ELF::EF_AMDGPU_FEATURE_SRAMECC_UNSUPPORTED_V4;
641     break;
642   case AMDGPU::IsaInfo::TargetIDSetting::Any:
643     EFlagsV4 |= ELF::EF_AMDGPU_FEATURE_SRAMECC_ANY_V4;
644     break;
645   case AMDGPU::IsaInfo::TargetIDSetting::Off:
646     EFlagsV4 |= ELF::EF_AMDGPU_FEATURE_SRAMECC_OFF_V4;
647     break;
648   case AMDGPU::IsaInfo::TargetIDSetting::On:
649     EFlagsV4 |= ELF::EF_AMDGPU_FEATURE_SRAMECC_ON_V4;
650     break;
651   }
652 
653   return EFlagsV4;
654 }
655 
656 void AMDGPUTargetELFStreamer::EmitDirectiveAMDGCNTarget() {}
657 
658 void AMDGPUTargetELFStreamer::EmitDirectiveHSACodeObjectVersion(
659     uint32_t Major, uint32_t Minor) {
660 
661   EmitNote(ElfNote::NoteNameV2, MCConstantExpr::create(8, getContext()),
662            ELF::NT_AMD_HSA_CODE_OBJECT_VERSION, [&](MCELFStreamer &OS) {
663              OS.emitInt32(Major);
664              OS.emitInt32(Minor);
665            });
666 }
667 
668 void
669 AMDGPUTargetELFStreamer::EmitDirectiveHSACodeObjectISAV2(uint32_t Major,
670                                                          uint32_t Minor,
671                                                          uint32_t Stepping,
672                                                          StringRef VendorName,
673                                                          StringRef ArchName) {
674   uint16_t VendorNameSize = VendorName.size() + 1;
675   uint16_t ArchNameSize = ArchName.size() + 1;
676 
677   unsigned DescSZ = sizeof(VendorNameSize) + sizeof(ArchNameSize) +
678     sizeof(Major) + sizeof(Minor) + sizeof(Stepping) +
679     VendorNameSize + ArchNameSize;
680 
681   convertIsaVersionV2(Major, Minor, Stepping, TargetID->isSramEccOnOrAny(), TargetID->isXnackOnOrAny());
682   EmitNote(ElfNote::NoteNameV2, MCConstantExpr::create(DescSZ, getContext()),
683            ELF::NT_AMD_HSA_ISA_VERSION, [&](MCELFStreamer &OS) {
684              OS.emitInt16(VendorNameSize);
685              OS.emitInt16(ArchNameSize);
686              OS.emitInt32(Major);
687              OS.emitInt32(Minor);
688              OS.emitInt32(Stepping);
689              OS.emitBytes(VendorName);
690              OS.emitInt8(0); // NULL terminate VendorName
691              OS.emitBytes(ArchName);
692              OS.emitInt8(0); // NULL terminte ArchName
693            });
694 }
695 
696 void
697 AMDGPUTargetELFStreamer::EmitAMDKernelCodeT(const amd_kernel_code_t &Header) {
698 
699   MCStreamer &OS = getStreamer();
700   OS.PushSection();
701   OS.emitBytes(StringRef((const char*)&Header, sizeof(Header)));
702   OS.PopSection();
703 }
704 
705 void AMDGPUTargetELFStreamer::EmitAMDGPUSymbolType(StringRef SymbolName,
706                                                    unsigned Type) {
707   MCSymbolELF *Symbol = cast<MCSymbolELF>(
708       getStreamer().getContext().getOrCreateSymbol(SymbolName));
709   Symbol->setType(Type);
710 }
711 
712 void AMDGPUTargetELFStreamer::emitAMDGPULDS(MCSymbol *Symbol, unsigned Size,
713                                             Align Alignment) {
714   MCSymbolELF *SymbolELF = cast<MCSymbolELF>(Symbol);
715   SymbolELF->setType(ELF::STT_OBJECT);
716 
717   if (!SymbolELF->isBindingSet()) {
718     SymbolELF->setBinding(ELF::STB_GLOBAL);
719     SymbolELF->setExternal(true);
720   }
721 
722   if (SymbolELF->declareCommon(Size, Alignment.value(), true)) {
723     report_fatal_error("Symbol: " + Symbol->getName() +
724                        " redeclared as different type");
725   }
726 
727   SymbolELF->setIndex(ELF::SHN_AMDGPU_LDS);
728   SymbolELF->setSize(MCConstantExpr::create(Size, getContext()));
729 }
730 
731 bool AMDGPUTargetELFStreamer::EmitISAVersion() {
732   // Create two labels to mark the beginning and end of the desc field
733   // and a MCExpr to calculate the size of the desc field.
734   auto &Context = getContext();
735   auto *DescBegin = Context.createTempSymbol();
736   auto *DescEnd = Context.createTempSymbol();
737   auto *DescSZ = MCBinaryExpr::createSub(
738     MCSymbolRefExpr::create(DescEnd, Context),
739     MCSymbolRefExpr::create(DescBegin, Context), Context);
740 
741   EmitNote(ElfNote::NoteNameV2, DescSZ, ELF::NT_AMD_HSA_ISA_NAME,
742            [&](MCELFStreamer &OS) {
743              OS.emitLabel(DescBegin);
744              OS.emitBytes(getTargetID()->toString());
745              OS.emitLabel(DescEnd);
746            });
747   return true;
748 }
749 
750 bool AMDGPUTargetELFStreamer::EmitHSAMetadata(msgpack::Document &HSAMetadataDoc,
751                                               bool Strict) {
752   HSAMD::V3::MetadataVerifier Verifier(Strict);
753   if (!Verifier.verify(HSAMetadataDoc.getRoot()))
754     return false;
755 
756   std::string HSAMetadataString;
757   HSAMetadataDoc.writeToBlob(HSAMetadataString);
758 
759   // Create two labels to mark the beginning and end of the desc field
760   // and a MCExpr to calculate the size of the desc field.
761   auto &Context = getContext();
762   auto *DescBegin = Context.createTempSymbol();
763   auto *DescEnd = Context.createTempSymbol();
764   auto *DescSZ = MCBinaryExpr::createSub(
765       MCSymbolRefExpr::create(DescEnd, Context),
766       MCSymbolRefExpr::create(DescBegin, Context), Context);
767 
768   EmitNote(ElfNote::NoteNameV3, DescSZ, ELF::NT_AMDGPU_METADATA,
769            [&](MCELFStreamer &OS) {
770              OS.emitLabel(DescBegin);
771              OS.emitBytes(HSAMetadataString);
772              OS.emitLabel(DescEnd);
773            });
774   return true;
775 }
776 
777 bool AMDGPUTargetELFStreamer::EmitHSAMetadata(
778     const AMDGPU::HSAMD::Metadata &HSAMetadata) {
779   std::string HSAMetadataString;
780   if (HSAMD::toString(HSAMetadata, HSAMetadataString))
781     return false;
782 
783   // Create two labels to mark the beginning and end of the desc field
784   // and a MCExpr to calculate the size of the desc field.
785   auto &Context = getContext();
786   auto *DescBegin = Context.createTempSymbol();
787   auto *DescEnd = Context.createTempSymbol();
788   auto *DescSZ = MCBinaryExpr::createSub(
789     MCSymbolRefExpr::create(DescEnd, Context),
790     MCSymbolRefExpr::create(DescBegin, Context), Context);
791 
792   EmitNote(ElfNote::NoteNameV2, DescSZ, ELF::NT_AMD_HSA_METADATA,
793            [&](MCELFStreamer &OS) {
794              OS.emitLabel(DescBegin);
795              OS.emitBytes(HSAMetadataString);
796              OS.emitLabel(DescEnd);
797            });
798   return true;
799 }
800 
801 bool AMDGPUTargetELFStreamer::EmitCodeEnd(const MCSubtargetInfo &STI) {
802   const uint32_t Encoded_s_code_end = 0xbf9f0000;
803   const uint32_t Encoded_s_nop = 0xbf800000;
804   uint32_t Encoded_pad = Encoded_s_code_end;
805 
806   // Instruction cache line size in bytes.
807   const unsigned Log2CacheLineSize = 6;
808   const unsigned CacheLineSize = 1u << Log2CacheLineSize;
809 
810   // Extra padding amount in bytes to support prefetch mode 3.
811   unsigned FillSize = 3 * CacheLineSize;
812 
813   if (AMDGPU::isGFX90A(STI)) {
814     Encoded_pad = Encoded_s_nop;
815     FillSize = 16 * CacheLineSize;
816   }
817 
818   MCStreamer &OS = getStreamer();
819   OS.PushSection();
820   OS.emitValueToAlignment(CacheLineSize, Encoded_pad, 4);
821   for (unsigned I = 0; I < FillSize; I += 4)
822     OS.emitInt32(Encoded_pad);
823   OS.PopSection();
824   return true;
825 }
826 
827 void AMDGPUTargetELFStreamer::EmitAmdhsaKernelDescriptor(
828     const MCSubtargetInfo &STI, StringRef KernelName,
829     const amdhsa::kernel_descriptor_t &KernelDescriptor, uint64_t NextVGPR,
830     uint64_t NextSGPR, bool ReserveVCC, bool ReserveFlatScr) {
831   auto &Streamer = getStreamer();
832   auto &Context = Streamer.getContext();
833 
834   MCSymbolELF *KernelCodeSymbol = cast<MCSymbolELF>(
835       Context.getOrCreateSymbol(Twine(KernelName)));
836   MCSymbolELF *KernelDescriptorSymbol = cast<MCSymbolELF>(
837       Context.getOrCreateSymbol(Twine(KernelName) + Twine(".kd")));
838 
839   // Copy kernel descriptor symbol's binding, other and visibility from the
840   // kernel code symbol.
841   KernelDescriptorSymbol->setBinding(KernelCodeSymbol->getBinding());
842   KernelDescriptorSymbol->setOther(KernelCodeSymbol->getOther());
843   KernelDescriptorSymbol->setVisibility(KernelCodeSymbol->getVisibility());
844   // Kernel descriptor symbol's type and size are fixed.
845   KernelDescriptorSymbol->setType(ELF::STT_OBJECT);
846   KernelDescriptorSymbol->setSize(
847       MCConstantExpr::create(sizeof(KernelDescriptor), Context));
848 
849   // The visibility of the kernel code symbol must be protected or less to allow
850   // static relocations from the kernel descriptor to be used.
851   if (KernelCodeSymbol->getVisibility() == ELF::STV_DEFAULT)
852     KernelCodeSymbol->setVisibility(ELF::STV_PROTECTED);
853 
854   Streamer.emitLabel(KernelDescriptorSymbol);
855   Streamer.emitInt32(KernelDescriptor.group_segment_fixed_size);
856   Streamer.emitInt32(KernelDescriptor.private_segment_fixed_size);
857   Streamer.emitInt32(KernelDescriptor.kernarg_size);
858 
859   for (uint8_t Res : KernelDescriptor.reserved0)
860     Streamer.emitInt8(Res);
861 
862   // FIXME: Remove the use of VK_AMDGPU_REL64 in the expression below. The
863   // expression being created is:
864   //   (start of kernel code) - (start of kernel descriptor)
865   // It implies R_AMDGPU_REL64, but ends up being R_AMDGPU_ABS64.
866   Streamer.emitValue(MCBinaryExpr::createSub(
867       MCSymbolRefExpr::create(
868           KernelCodeSymbol, MCSymbolRefExpr::VK_AMDGPU_REL64, Context),
869       MCSymbolRefExpr::create(
870           KernelDescriptorSymbol, MCSymbolRefExpr::VK_None, Context),
871       Context),
872       sizeof(KernelDescriptor.kernel_code_entry_byte_offset));
873   for (uint8_t Res : KernelDescriptor.reserved1)
874     Streamer.emitInt8(Res);
875   Streamer.emitInt32(KernelDescriptor.compute_pgm_rsrc3);
876   Streamer.emitInt32(KernelDescriptor.compute_pgm_rsrc1);
877   Streamer.emitInt32(KernelDescriptor.compute_pgm_rsrc2);
878   Streamer.emitInt16(KernelDescriptor.kernel_code_properties);
879   for (uint8_t Res : KernelDescriptor.reserved2)
880     Streamer.emitInt8(Res);
881 }
882