1 //===- DWARFEmitter - Convert YAML to DWARF binary data -------------------===// 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 DWARF component of yaml2obj. Provided as library code for tests. 11 /// 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/ObjectYAML/DWARFEmitter.h" 15 #include "DWARFVisitor.h" 16 #include "llvm/ADT/StringMap.h" 17 #include "llvm/ADT/StringRef.h" 18 #include "llvm/BinaryFormat/Dwarf.h" 19 #include "llvm/ObjectYAML/DWARFYAML.h" 20 #include "llvm/Support/Errc.h" 21 #include "llvm/Support/Error.h" 22 #include "llvm/Support/Host.h" 23 #include "llvm/Support/LEB128.h" 24 #include "llvm/Support/MathExtras.h" 25 #include "llvm/Support/MemoryBuffer.h" 26 #include "llvm/Support/SourceMgr.h" 27 #include "llvm/Support/SwapByteOrder.h" 28 #include "llvm/Support/YAMLTraits.h" 29 #include "llvm/Support/raw_ostream.h" 30 #include <algorithm> 31 #include <cassert> 32 #include <cstddef> 33 #include <cstdint> 34 #include <memory> 35 #include <string> 36 #include <vector> 37 38 using namespace llvm; 39 40 template <typename T> 41 static void writeInteger(T Integer, raw_ostream &OS, bool IsLittleEndian) { 42 if (IsLittleEndian != sys::IsLittleEndianHost) 43 sys::swapByteOrder(Integer); 44 OS.write(reinterpret_cast<char *>(&Integer), sizeof(T)); 45 } 46 47 static Error writeVariableSizedInteger(uint64_t Integer, size_t Size, 48 raw_ostream &OS, bool IsLittleEndian) { 49 if (8 == Size) 50 writeInteger((uint64_t)Integer, OS, IsLittleEndian); 51 else if (4 == Size) 52 writeInteger((uint32_t)Integer, OS, IsLittleEndian); 53 else if (2 == Size) 54 writeInteger((uint16_t)Integer, OS, IsLittleEndian); 55 else if (1 == Size) 56 writeInteger((uint8_t)Integer, OS, IsLittleEndian); 57 else 58 return createStringError(errc::not_supported, 59 "invalid integer write size: %zu", Size); 60 61 return Error::success(); 62 } 63 64 static void ZeroFillBytes(raw_ostream &OS, size_t Size) { 65 std::vector<uint8_t> FillData; 66 FillData.insert(FillData.begin(), Size, 0); 67 OS.write(reinterpret_cast<char *>(FillData.data()), Size); 68 } 69 70 static void writeInitialLength(const DWARFYAML::InitialLength &Length, 71 raw_ostream &OS, bool IsLittleEndian) { 72 writeInteger((uint32_t)Length.TotalLength, OS, IsLittleEndian); 73 if (Length.isDWARF64()) 74 writeInteger((uint64_t)Length.TotalLength64, OS, IsLittleEndian); 75 } 76 77 static void writeInitialLength(const dwarf::DwarfFormat Format, 78 const uint64_t Length, raw_ostream &OS, 79 bool IsLittleEndian) { 80 bool IsDWARF64 = Format == dwarf::DWARF64; 81 if (IsDWARF64) 82 cantFail(writeVariableSizedInteger(dwarf::DW_LENGTH_DWARF64, 4, OS, 83 IsLittleEndian)); 84 cantFail( 85 writeVariableSizedInteger(Length, IsDWARF64 ? 8 : 4, OS, IsLittleEndian)); 86 } 87 88 Error DWARFYAML::emitDebugStr(raw_ostream &OS, const DWARFYAML::Data &DI) { 89 for (auto Str : DI.DebugStrings) { 90 OS.write(Str.data(), Str.size()); 91 OS.write('\0'); 92 } 93 94 return Error::success(); 95 } 96 97 Error DWARFYAML::emitDebugAbbrev(raw_ostream &OS, const DWARFYAML::Data &DI) { 98 uint64_t AbbrevCode = 0; 99 for (auto AbbrevDecl : DI.AbbrevDecls) { 100 AbbrevCode = AbbrevDecl.Code ? (uint64_t)*AbbrevDecl.Code : AbbrevCode + 1; 101 encodeULEB128(AbbrevCode, OS); 102 encodeULEB128(AbbrevDecl.Tag, OS); 103 OS.write(AbbrevDecl.Children); 104 for (auto Attr : AbbrevDecl.Attributes) { 105 encodeULEB128(Attr.Attribute, OS); 106 encodeULEB128(Attr.Form, OS); 107 if (Attr.Form == dwarf::DW_FORM_implicit_const) 108 encodeSLEB128(Attr.Value, OS); 109 } 110 encodeULEB128(0, OS); 111 encodeULEB128(0, OS); 112 } 113 114 // The abbreviations for a given compilation unit end with an entry consisting 115 // of a 0 byte for the abbreviation code. 116 OS.write_zeros(1); 117 118 return Error::success(); 119 } 120 121 Error DWARFYAML::emitDebugAranges(raw_ostream &OS, const DWARFYAML::Data &DI) { 122 for (auto Range : DI.ARanges) { 123 auto HeaderStart = OS.tell(); 124 writeInitialLength(Range.Format, Range.Length, OS, DI.IsLittleEndian); 125 writeInteger((uint16_t)Range.Version, OS, DI.IsLittleEndian); 126 if (Range.Format == dwarf::DWARF64) 127 writeInteger((uint64_t)Range.CuOffset, OS, DI.IsLittleEndian); 128 else 129 writeInteger((uint32_t)Range.CuOffset, OS, DI.IsLittleEndian); 130 writeInteger((uint8_t)Range.AddrSize, OS, DI.IsLittleEndian); 131 writeInteger((uint8_t)Range.SegSize, OS, DI.IsLittleEndian); 132 133 auto HeaderSize = OS.tell() - HeaderStart; 134 auto FirstDescriptor = alignTo(HeaderSize, Range.AddrSize * 2); 135 ZeroFillBytes(OS, FirstDescriptor - HeaderSize); 136 137 for (auto Descriptor : Range.Descriptors) { 138 if (Error Err = writeVariableSizedInteger( 139 Descriptor.Address, Range.AddrSize, OS, DI.IsLittleEndian)) 140 return createStringError(errc::not_supported, 141 "unable to write debug_aranges address: %s", 142 toString(std::move(Err)).c_str()); 143 cantFail(writeVariableSizedInteger(Descriptor.Length, Range.AddrSize, OS, 144 DI.IsLittleEndian)); 145 } 146 ZeroFillBytes(OS, Range.AddrSize * 2); 147 } 148 149 return Error::success(); 150 } 151 152 Error DWARFYAML::emitDebugRanges(raw_ostream &OS, const DWARFYAML::Data &DI) { 153 const size_t RangesOffset = OS.tell(); 154 uint64_t EntryIndex = 0; 155 for (auto DebugRanges : DI.DebugRanges) { 156 const size_t CurrOffset = OS.tell() - RangesOffset; 157 if (DebugRanges.Offset && (uint64_t)*DebugRanges.Offset < CurrOffset) 158 return createStringError(errc::invalid_argument, 159 "'Offset' for 'debug_ranges' with index " + 160 Twine(EntryIndex) + 161 " must be greater than or equal to the " 162 "number of bytes written already (0x" + 163 Twine::utohexstr(CurrOffset) + ")"); 164 if (DebugRanges.Offset) 165 ZeroFillBytes(OS, *DebugRanges.Offset - CurrOffset); 166 167 uint8_t AddrSize; 168 if (DebugRanges.AddrSize) 169 AddrSize = *DebugRanges.AddrSize; 170 else 171 AddrSize = DI.Is64BitAddrSize ? 8 : 4; 172 for (auto Entry : DebugRanges.Entries) { 173 if (Error Err = writeVariableSizedInteger(Entry.LowOffset, AddrSize, OS, 174 DI.IsLittleEndian)) 175 return createStringError( 176 errc::not_supported, 177 "unable to write debug_ranges address offset: %s", 178 toString(std::move(Err)).c_str()); 179 cantFail(writeVariableSizedInteger(Entry.HighOffset, AddrSize, OS, 180 DI.IsLittleEndian)); 181 } 182 ZeroFillBytes(OS, AddrSize * 2); 183 ++EntryIndex; 184 } 185 186 return Error::success(); 187 } 188 189 Error DWARFYAML::emitPubSection(raw_ostream &OS, 190 const DWARFYAML::PubSection &Sect, 191 bool IsLittleEndian, bool IsGNUPubSec) { 192 writeInitialLength(Sect.Length, OS, IsLittleEndian); 193 writeInteger((uint16_t)Sect.Version, OS, IsLittleEndian); 194 writeInteger((uint32_t)Sect.UnitOffset, OS, IsLittleEndian); 195 writeInteger((uint32_t)Sect.UnitSize, OS, IsLittleEndian); 196 for (auto Entry : Sect.Entries) { 197 writeInteger((uint32_t)Entry.DieOffset, OS, IsLittleEndian); 198 if (IsGNUPubSec) 199 writeInteger((uint8_t)Entry.Descriptor, OS, IsLittleEndian); 200 OS.write(Entry.Name.data(), Entry.Name.size()); 201 OS.write('\0'); 202 } 203 204 return Error::success(); 205 } 206 207 namespace { 208 /// An extension of the DWARFYAML::ConstVisitor which writes compile 209 /// units and DIEs to a stream. 210 class DumpVisitor : public DWARFYAML::ConstVisitor { 211 raw_ostream &OS; 212 213 protected: 214 void onStartCompileUnit(const DWARFYAML::Unit &CU) override { 215 writeInitialLength(CU.Format, CU.Length, OS, DebugInfo.IsLittleEndian); 216 writeInteger((uint16_t)CU.Version, OS, DebugInfo.IsLittleEndian); 217 if (CU.Version >= 5) { 218 writeInteger((uint8_t)CU.Type, OS, DebugInfo.IsLittleEndian); 219 writeInteger((uint8_t)CU.AddrSize, OS, DebugInfo.IsLittleEndian); 220 cantFail(writeVariableSizedInteger(CU.AbbrOffset, 221 CU.Format == dwarf::DWARF64 ? 8 : 4, 222 OS, DebugInfo.IsLittleEndian)); 223 } else { 224 cantFail(writeVariableSizedInteger(CU.AbbrOffset, 225 CU.Format == dwarf::DWARF64 ? 8 : 4, 226 OS, DebugInfo.IsLittleEndian)); 227 writeInteger((uint8_t)CU.AddrSize, OS, DebugInfo.IsLittleEndian); 228 } 229 } 230 231 void onStartDIE(const DWARFYAML::Unit &CU, 232 const DWARFYAML::Entry &DIE) override { 233 encodeULEB128(DIE.AbbrCode, OS); 234 } 235 236 void onValue(const uint8_t U) override { 237 writeInteger(U, OS, DebugInfo.IsLittleEndian); 238 } 239 240 void onValue(const uint16_t U) override { 241 writeInteger(U, OS, DebugInfo.IsLittleEndian); 242 } 243 244 void onValue(const uint32_t U) override { 245 writeInteger(U, OS, DebugInfo.IsLittleEndian); 246 } 247 248 void onValue(const uint64_t U, const bool LEB = false) override { 249 if (LEB) 250 encodeULEB128(U, OS); 251 else 252 writeInteger(U, OS, DebugInfo.IsLittleEndian); 253 } 254 255 void onValue(const int64_t S, const bool LEB = false) override { 256 if (LEB) 257 encodeSLEB128(S, OS); 258 else 259 writeInteger(S, OS, DebugInfo.IsLittleEndian); 260 } 261 262 void onValue(const StringRef String) override { 263 OS.write(String.data(), String.size()); 264 OS.write('\0'); 265 } 266 267 void onValue(const MemoryBufferRef MBR) override { 268 OS.write(MBR.getBufferStart(), MBR.getBufferSize()); 269 } 270 271 public: 272 DumpVisitor(const DWARFYAML::Data &DI, raw_ostream &Out) 273 : DWARFYAML::ConstVisitor(DI), OS(Out) {} 274 }; 275 } // namespace 276 277 Error DWARFYAML::emitDebugInfo(raw_ostream &OS, const DWARFYAML::Data &DI) { 278 DumpVisitor Visitor(DI, OS); 279 return Visitor.traverseDebugInfo(); 280 } 281 282 static void emitFileEntry(raw_ostream &OS, const DWARFYAML::File &File) { 283 OS.write(File.Name.data(), File.Name.size()); 284 OS.write('\0'); 285 encodeULEB128(File.DirIdx, OS); 286 encodeULEB128(File.ModTime, OS); 287 encodeULEB128(File.Length, OS); 288 } 289 290 Error DWARFYAML::emitDebugLine(raw_ostream &OS, const DWARFYAML::Data &DI) { 291 for (const auto &LineTable : DI.DebugLines) { 292 writeInitialLength(LineTable.Format, LineTable.Length, OS, 293 DI.IsLittleEndian); 294 uint64_t SizeOfPrologueLength = LineTable.Format == dwarf::DWARF64 ? 8 : 4; 295 writeInteger((uint16_t)LineTable.Version, OS, DI.IsLittleEndian); 296 cantFail(writeVariableSizedInteger( 297 LineTable.PrologueLength, SizeOfPrologueLength, OS, DI.IsLittleEndian)); 298 writeInteger((uint8_t)LineTable.MinInstLength, OS, DI.IsLittleEndian); 299 if (LineTable.Version >= 4) 300 writeInteger((uint8_t)LineTable.MaxOpsPerInst, OS, DI.IsLittleEndian); 301 writeInteger((uint8_t)LineTable.DefaultIsStmt, OS, DI.IsLittleEndian); 302 writeInteger((uint8_t)LineTable.LineBase, OS, DI.IsLittleEndian); 303 writeInteger((uint8_t)LineTable.LineRange, OS, DI.IsLittleEndian); 304 writeInteger((uint8_t)LineTable.OpcodeBase, OS, DI.IsLittleEndian); 305 306 for (auto OpcodeLength : LineTable.StandardOpcodeLengths) 307 writeInteger((uint8_t)OpcodeLength, OS, DI.IsLittleEndian); 308 309 for (auto IncludeDir : LineTable.IncludeDirs) { 310 OS.write(IncludeDir.data(), IncludeDir.size()); 311 OS.write('\0'); 312 } 313 OS.write('\0'); 314 315 for (auto File : LineTable.Files) 316 emitFileEntry(OS, File); 317 OS.write('\0'); 318 319 for (auto Op : LineTable.Opcodes) { 320 writeInteger((uint8_t)Op.Opcode, OS, DI.IsLittleEndian); 321 if (Op.Opcode == 0) { 322 encodeULEB128(Op.ExtLen, OS); 323 writeInteger((uint8_t)Op.SubOpcode, OS, DI.IsLittleEndian); 324 switch (Op.SubOpcode) { 325 case dwarf::DW_LNE_set_address: 326 case dwarf::DW_LNE_set_discriminator: 327 // TODO: Test this error. 328 if (Error Err = writeVariableSizedInteger( 329 Op.Data, DI.CompileUnits[0].AddrSize, OS, DI.IsLittleEndian)) 330 return Err; 331 break; 332 case dwarf::DW_LNE_define_file: 333 emitFileEntry(OS, Op.FileEntry); 334 break; 335 case dwarf::DW_LNE_end_sequence: 336 break; 337 default: 338 for (auto OpByte : Op.UnknownOpcodeData) 339 writeInteger((uint8_t)OpByte, OS, DI.IsLittleEndian); 340 } 341 } else if (Op.Opcode < LineTable.OpcodeBase) { 342 switch (Op.Opcode) { 343 case dwarf::DW_LNS_copy: 344 case dwarf::DW_LNS_negate_stmt: 345 case dwarf::DW_LNS_set_basic_block: 346 case dwarf::DW_LNS_const_add_pc: 347 case dwarf::DW_LNS_set_prologue_end: 348 case dwarf::DW_LNS_set_epilogue_begin: 349 break; 350 351 case dwarf::DW_LNS_advance_pc: 352 case dwarf::DW_LNS_set_file: 353 case dwarf::DW_LNS_set_column: 354 case dwarf::DW_LNS_set_isa: 355 encodeULEB128(Op.Data, OS); 356 break; 357 358 case dwarf::DW_LNS_advance_line: 359 encodeSLEB128(Op.SData, OS); 360 break; 361 362 case dwarf::DW_LNS_fixed_advance_pc: 363 writeInteger((uint16_t)Op.Data, OS, DI.IsLittleEndian); 364 break; 365 366 default: 367 for (auto OpData : Op.StandardOpcodeData) { 368 encodeULEB128(OpData, OS); 369 } 370 } 371 } 372 } 373 } 374 375 return Error::success(); 376 } 377 378 Error DWARFYAML::emitDebugAddr(raw_ostream &OS, const Data &DI) { 379 for (const AddrTableEntry &TableEntry : DI.DebugAddr) { 380 uint8_t AddrSize; 381 if (TableEntry.AddrSize) 382 AddrSize = *TableEntry.AddrSize; 383 else 384 AddrSize = DI.Is64BitAddrSize ? 8 : 4; 385 386 uint64_t Length; 387 if (TableEntry.Length) 388 Length = (uint64_t)*TableEntry.Length; 389 else 390 // 2 (version) + 1 (address_size) + 1 (segment_selector_size) = 4 391 Length = 4 + (AddrSize + TableEntry.SegSelectorSize) * 392 TableEntry.SegAddrPairs.size(); 393 394 writeInitialLength(TableEntry.Format, Length, OS, DI.IsLittleEndian); 395 writeInteger((uint16_t)TableEntry.Version, OS, DI.IsLittleEndian); 396 writeInteger((uint8_t)AddrSize, OS, DI.IsLittleEndian); 397 writeInteger((uint8_t)TableEntry.SegSelectorSize, OS, DI.IsLittleEndian); 398 399 for (const SegAddrPair &Pair : TableEntry.SegAddrPairs) { 400 if (TableEntry.SegSelectorSize != 0) 401 if (Error Err = writeVariableSizedInteger(Pair.Segment, 402 TableEntry.SegSelectorSize, 403 OS, DI.IsLittleEndian)) 404 return createStringError(errc::not_supported, 405 "unable to write debug_addr segment: %s", 406 toString(std::move(Err)).c_str()); 407 if (AddrSize != 0) 408 if (Error Err = writeVariableSizedInteger(Pair.Address, AddrSize, OS, 409 DI.IsLittleEndian)) 410 return createStringError(errc::not_supported, 411 "unable to write debug_addr address: %s", 412 toString(std::move(Err)).c_str()); 413 } 414 } 415 416 return Error::success(); 417 } 418 419 using EmitFuncType = Error (*)(raw_ostream &, const DWARFYAML::Data &); 420 421 static Error 422 emitDebugSectionImpl(const DWARFYAML::Data &DI, EmitFuncType EmitFunc, 423 StringRef Sec, 424 StringMap<std::unique_ptr<MemoryBuffer>> &OutputBuffers) { 425 std::string Data; 426 raw_string_ostream DebugInfoStream(Data); 427 if (Error Err = EmitFunc(DebugInfoStream, DI)) 428 return Err; 429 DebugInfoStream.flush(); 430 if (!Data.empty()) 431 OutputBuffers[Sec] = MemoryBuffer::getMemBufferCopy(Data); 432 433 return Error::success(); 434 } 435 436 namespace { 437 class DIEFixupVisitor : public DWARFYAML::Visitor { 438 uint64_t Length; 439 440 public: 441 DIEFixupVisitor(DWARFYAML::Data &DI) : DWARFYAML::Visitor(DI){}; 442 443 protected: 444 void onStartCompileUnit(DWARFYAML::Unit &CU) override { 445 // Size of the unit header, excluding the length field itself. 446 Length = CU.Version >= 5 ? 8 : 7; 447 } 448 449 void onEndCompileUnit(DWARFYAML::Unit &CU) override { CU.Length = Length; } 450 451 void onStartDIE(DWARFYAML::Unit &CU, DWARFYAML::Entry &DIE) override { 452 Length += getULEB128Size(DIE.AbbrCode); 453 } 454 455 void onValue(const uint8_t U) override { Length += 1; } 456 void onValue(const uint16_t U) override { Length += 2; } 457 void onValue(const uint32_t U) override { Length += 4; } 458 void onValue(const uint64_t U, const bool LEB = false) override { 459 if (LEB) 460 Length += getULEB128Size(U); 461 else 462 Length += 8; 463 } 464 void onValue(const int64_t S, const bool LEB = false) override { 465 if (LEB) 466 Length += getSLEB128Size(S); 467 else 468 Length += 8; 469 } 470 void onValue(const StringRef String) override { Length += String.size() + 1; } 471 472 void onValue(const MemoryBufferRef MBR) override { 473 Length += MBR.getBufferSize(); 474 } 475 }; 476 } // namespace 477 478 Expected<StringMap<std::unique_ptr<MemoryBuffer>>> 479 DWARFYAML::emitDebugSections(StringRef YAMLString, bool ApplyFixups, 480 bool IsLittleEndian) { 481 auto CollectDiagnostic = [](const SMDiagnostic &Diag, void *DiagContext) { 482 *static_cast<SMDiagnostic *>(DiagContext) = Diag; 483 }; 484 485 SMDiagnostic GeneratedDiag; 486 yaml::Input YIn(YAMLString, /*Ctxt=*/nullptr, CollectDiagnostic, 487 &GeneratedDiag); 488 489 DWARFYAML::Data DI; 490 DI.IsLittleEndian = IsLittleEndian; 491 YIn >> DI; 492 if (YIn.error()) 493 return createStringError(YIn.error(), GeneratedDiag.getMessage()); 494 495 if (ApplyFixups) { 496 DIEFixupVisitor DIFixer(DI); 497 if (Error Err = DIFixer.traverseDebugInfo()) 498 return std::move(Err); 499 } 500 501 StringMap<std::unique_ptr<MemoryBuffer>> DebugSections; 502 Error Err = emitDebugSectionImpl(DI, &DWARFYAML::emitDebugInfo, "debug_info", 503 DebugSections); 504 Err = joinErrors(std::move(Err), 505 emitDebugSectionImpl(DI, &DWARFYAML::emitDebugLine, 506 "debug_line", DebugSections)); 507 Err = joinErrors(std::move(Err), 508 emitDebugSectionImpl(DI, &DWARFYAML::emitDebugStr, 509 "debug_str", DebugSections)); 510 Err = joinErrors(std::move(Err), 511 emitDebugSectionImpl(DI, &DWARFYAML::emitDebugAbbrev, 512 "debug_abbrev", DebugSections)); 513 Err = joinErrors(std::move(Err), 514 emitDebugSectionImpl(DI, &DWARFYAML::emitDebugAranges, 515 "debug_aranges", DebugSections)); 516 Err = joinErrors(std::move(Err), 517 emitDebugSectionImpl(DI, &DWARFYAML::emitDebugRanges, 518 "debug_ranges", DebugSections)); 519 520 if (Err) 521 return std::move(Err); 522 return std::move(DebugSections); 523 } 524