llvm/lib/ObjectYAML/DWARFEmitter.cpp

   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 "llvm/ADT/ArrayRef.h"
  16 #include "llvm/ADT/StringMap.h"
  17 #include "llvm/ADT/StringRef.h"
  18 #include "llvm/ADT/StringSwitch.h"
  19 #include "llvm/BinaryFormat/Dwarf.h"
  20 #include "llvm/ObjectYAML/DWARFYAML.h"
  21 #include "llvm/Support/Errc.h"
  22 #include "llvm/Support/Error.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 "llvm/TargetParser/Host.h"
  31 #include <cassert>
  32 #include <cstddef>
  33 #include <cstdint>
  34 #include <memory>
  35 #include <optional>
  36 #include <string>
  37 #include <vector>
  38
  39 using namespace llvm;
  40
  41 template <typename T>
  42 static void writeInteger(T Integer, raw_ostream &OS, bool IsLittleEndian) {
  43   if (IsLittleEndian != sys::IsLittleEndianHost)
  44     sys::swapByteOrder(Integer);
  45   OS.write(reinterpret_cast<char *>(&Integer), sizeof(T));
  46 }
  47
  48 static Error writeVariableSizedInteger(uint64_t Integer, size_t Size,
  49                                        raw_ostream &OS, bool IsLittleEndian) {
  50   if (8 == Size)
  51     writeInteger((uint64_t)Integer, OS, IsLittleEndian);
  52   else if (4 == Size)
  53     writeInteger((uint32_t)Integer, OS, IsLittleEndian);
  54   else if (2 == Size)
  55     writeInteger((uint16_t)Integer, OS, IsLittleEndian);
  56   else if (1 == Size)
  57     writeInteger((uint8_t)Integer, OS, IsLittleEndian);
  58   else
  59     return createStringError(errc::not_supported,
  60                              "invalid integer write size: %zu", Size);
  61
  62   return Error::success();
  63 }
  64
  65 static void ZeroFillBytes(raw_ostream &OS, size_t Size) {
  66   std::vector<uint8_t> FillData(Size, 0);
  67   OS.write(reinterpret_cast<char *>(FillData.data()), Size);
  68 }
  69
  70 static void writeInitialLength(const dwarf::DwarfFormat Format,
  71                                const uint64_t Length, raw_ostream &OS,
  72                                bool IsLittleEndian) {
  73   bool IsDWARF64 = Format == dwarf::DWARF64;
  74   if (IsDWARF64)
  75     cantFail(writeVariableSizedInteger(dwarf::DW_LENGTH_DWARF64, 4, OS,
  76                                        IsLittleEndian));
  77   cantFail(
  78       writeVariableSizedInteger(Length, IsDWARF64 ? 8 : 4, OS, IsLittleEndian));
  79 }
  80
  81 static void writeDWARFOffset(uint64_t Offset, dwarf::DwarfFormat Format,
  82                              raw_ostream &OS, bool IsLittleEndian) {
  83   cantFail(writeVariableSizedInteger(Offset, Format == dwarf::DWARF64 ? 8 : 4,
  84                                      OS, IsLittleEndian));
  85 }
  86
  87 Error DWARFYAML::emitDebugStr(raw_ostream &OS, const DWARFYAML::Data &DI) {
  88   for (StringRef Str : *DI.DebugStrings) {
  89     OS.write(Str.data(), Str.size());
  90     OS.write('\0');
  91   }
  92
  93   return Error::success();
  94 }
  95
  96 StringRef DWARFYAML::Data::getAbbrevTableContentByIndex(uint64_t Index) const {
  97   assert(Index < DebugAbbrev.size() &&
  98          "Index should be less than the size of DebugAbbrev array");
  99   auto It = AbbrevTableContents.find(Index);
 100   if (It != AbbrevTableContents.cend())
 101     return It->second;
 102
 103   std::string AbbrevTableBuffer;
 104   raw_string_ostream OS(AbbrevTableBuffer);
 105
 106   uint64_t AbbrevCode = 0;
 107   for (const DWARFYAML::Abbrev &AbbrevDecl : DebugAbbrev[Index].Table) {
 108     AbbrevCode = AbbrevDecl.Code ? (uint64_t)*AbbrevDecl.Code : AbbrevCode + 1;
 109     encodeULEB128(AbbrevCode, OS);
 110     encodeULEB128(AbbrevDecl.Tag, OS);
 111     OS.write(AbbrevDecl.Children);
 112     for (const auto &Attr : AbbrevDecl.Attributes) {
 113       encodeULEB128(Attr.Attribute, OS);
 114       encodeULEB128(Attr.Form, OS);
 115       if (Attr.Form == dwarf::DW_FORM_implicit_const)
 116         encodeSLEB128(Attr.Value, OS);
 117     }
 118     encodeULEB128(0, OS);
 119     encodeULEB128(0, OS);
 120   }
 121
 122   // The abbreviations for a given compilation unit end with an entry
 123   // consisting of a 0 byte for the abbreviation code.
 124   OS.write_zeros(1);
 125
 126   AbbrevTableContents.insert({Index, AbbrevTableBuffer});
 127
 128   return AbbrevTableContents[Index];
 129 }
 130
 131 Error DWARFYAML::emitDebugAbbrev(raw_ostream &OS, const DWARFYAML::Data &DI) {
 132   for (uint64_t I = 0; I < DI.DebugAbbrev.size(); ++I) {
 133     StringRef AbbrevTableContent = DI.getAbbrevTableContentByIndex(I);
 134     OS.write(AbbrevTableContent.data(), AbbrevTableContent.size());
 135   }
 136
 137   return Error::success();
 138 }
 139
 140 Error DWARFYAML::emitDebugAranges(raw_ostream &OS, const DWARFYAML::Data &DI) {
 141   assert(DI.DebugAranges && "unexpected emitDebugAranges() call");
 142   for (const auto &Range : *DI.DebugAranges) {
 143     uint8_t AddrSize;
 144     if (Range.AddrSize)
 145       AddrSize = *Range.AddrSize;
 146     else
 147       AddrSize = DI.Is64BitAddrSize ? 8 : 4;
 148
 149     uint64_t Length = 4; // sizeof(version) 2 + sizeof(address_size) 1 +
 150                          // sizeof(segment_selector_size) 1
 151     Length +=
 152         Range.Format == dwarf::DWARF64 ? 8 : 4; // sizeof(debug_info_offset)
 153
 154     const uint64_t HeaderLength =
 155         Length + (Range.Format == dwarf::DWARF64
 156                       ? 12
 157                       : 4); // sizeof(unit_header) = 12 (DWARF64) or 4 (DWARF32)
 158     const uint64_t PaddedHeaderLength = alignTo(HeaderLength, AddrSize * 2);
 159
 160     if (Range.Length) {
 161       Length = *Range.Length;
 162     } else {
 163       Length += PaddedHeaderLength - HeaderLength;
 164       Length += AddrSize * 2 * (Range.Descriptors.size() + 1);
 165     }
 166
 167     writeInitialLength(Range.Format, Length, OS, DI.IsLittleEndian);
 168     writeInteger((uint16_t)Range.Version, OS, DI.IsLittleEndian);
 169     writeDWARFOffset(Range.CuOffset, Range.Format, OS, DI.IsLittleEndian);
 170     writeInteger((uint8_t)AddrSize, OS, DI.IsLittleEndian);
 171     writeInteger((uint8_t)Range.SegSize, OS, DI.IsLittleEndian);
 172     ZeroFillBytes(OS, PaddedHeaderLength - HeaderLength);
 173
 174     for (const auto &Descriptor : Range.Descriptors) {
 175       if (Error Err = writeVariableSizedInteger(Descriptor.Address, AddrSize,
 176                                                 OS, DI.IsLittleEndian))
 177         return createStringError(errc::not_supported,
 178                                  "unable to write debug_aranges address: %s",
 179                                  toString(std::move(Err)).c_str());
 180       cantFail(writeVariableSizedInteger(Descriptor.Length, AddrSize, OS,
 181                                          DI.IsLittleEndian));
 182     }
 183     ZeroFillBytes(OS, AddrSize * 2);
 184   }
 185
 186   return Error::success();
 187 }
 188
 189 Error DWARFYAML::emitDebugRanges(raw_ostream &OS, const DWARFYAML::Data &DI) {
 190   const size_t RangesOffset = OS.tell();
 191   uint64_t EntryIndex = 0;
 192   for (const auto &DebugRanges : *DI.DebugRanges) {
 193     const size_t CurrOffset = OS.tell() - RangesOffset;
 194     if (DebugRanges.Offset && (uint64_t)*DebugRanges.Offset < CurrOffset)
 195       return createStringError(errc::invalid_argument,
 196                                "'Offset' for 'debug_ranges' with index " +
 197                                    Twine(EntryIndex) +
 198                                    " must be greater than or equal to the "
 199                                    "number of bytes written already (0x" +
 200                                    Twine::utohexstr(CurrOffset) + ")");
 201     if (DebugRanges.Offset)
 202       ZeroFillBytes(OS, *DebugRanges.Offset - CurrOffset);
 203
 204     uint8_t AddrSize;
 205     if (DebugRanges.AddrSize)
 206       AddrSize = *DebugRanges.AddrSize;
 207     else
 208       AddrSize = DI.Is64BitAddrSize ? 8 : 4;
 209     for (const auto &Entry : DebugRanges.Entries) {
 210       if (Error Err = writeVariableSizedInteger(Entry.LowOffset, AddrSize, OS,
 211                                                 DI.IsLittleEndian))
 212         return createStringError(
 213             errc::not_supported,
 214             "unable to write debug_ranges address offset: %s",
 215             toString(std::move(Err)).c_str());
 216       cantFail(writeVariableSizedInteger(Entry.HighOffset, AddrSize, OS,
 217                                          DI.IsLittleEndian));
 218     }
 219     ZeroFillBytes(OS, AddrSize * 2);
 220     ++EntryIndex;
 221   }
 222
 223   return Error::success();
 224 }
 225
 226 static Error emitPubSection(raw_ostream &OS, const DWARFYAML::PubSection &Sect,
 227                             bool IsLittleEndian, bool IsGNUPubSec = false) {
 228   writeInitialLength(Sect.Format, Sect.Length, OS, IsLittleEndian);
 229   writeInteger((uint16_t)Sect.Version, OS, IsLittleEndian);
 230   writeInteger((uint32_t)Sect.UnitOffset, OS, IsLittleEndian);
 231   writeInteger((uint32_t)Sect.UnitSize, OS, IsLittleEndian);
 232   for (const auto &Entry : Sect.Entries) {
 233     writeInteger((uint32_t)Entry.DieOffset, OS, IsLittleEndian);
 234     if (IsGNUPubSec)
 235       writeInteger((uint8_t)Entry.Descriptor, OS, IsLittleEndian);
 236     OS.write(Entry.Name.data(), Entry.Name.size());
 237     OS.write('\0');
 238   }
 239   return Error::success();
 240 }
 241
 242 Error DWARFYAML::emitDebugPubnames(raw_ostream &OS, const Data &DI) {
 243   assert(DI.PubNames && "unexpected emitDebugPubnames() call");
 244   return emitPubSection(OS, *DI.PubNames, DI.IsLittleEndian);
 245 }
 246
 247 Error DWARFYAML::emitDebugPubtypes(raw_ostream &OS, const Data &DI) {
 248   assert(DI.PubTypes && "unexpected emitDebugPubtypes() call");
 249   return emitPubSection(OS, *DI.PubTypes, DI.IsLittleEndian);
 250 }
 251
 252 Error DWARFYAML::emitDebugGNUPubnames(raw_ostream &OS, const Data &DI) {
 253   assert(DI.GNUPubNames && "unexpected emitDebugGNUPubnames() call");
 254   return emitPubSection(OS, *DI.GNUPubNames, DI.IsLittleEndian,
 255                         /*IsGNUStyle=*/true);
 256 }
 257
 258 Error DWARFYAML::emitDebugGNUPubtypes(raw_ostream &OS, const Data &DI) {
 259   assert(DI.GNUPubTypes && "unexpected emitDebugGNUPubtypes() call");
 260   return emitPubSection(OS, *DI.GNUPubTypes, DI.IsLittleEndian,
 261                         /*IsGNUStyle=*/true);
 262 }
 263
 264 static Expected<uint64_t> writeDIE(const DWARFYAML::Data &DI, uint64_t CUIndex,
 265                                    uint64_t AbbrevTableID,
 266                                    const dwarf::FormParams &Params,
 267                                    const DWARFYAML::Entry &Entry,
 268                                    raw_ostream &OS, bool IsLittleEndian) {
 269   uint64_t EntryBegin = OS.tell();
 270   encodeULEB128(Entry.AbbrCode, OS);
 271   uint32_t AbbrCode = Entry.AbbrCode;
 272   if (AbbrCode == 0 || Entry.Values.empty())
 273     return OS.tell() - EntryBegin;
 274
 275   Expected<DWARFYAML::Data::AbbrevTableInfo> AbbrevTableInfoOrErr =
 276       DI.getAbbrevTableInfoByID(AbbrevTableID);
 277   if (!AbbrevTableInfoOrErr)
 278     return createStringError(errc::invalid_argument,
 279                              toString(AbbrevTableInfoOrErr.takeError()) +
 280                                  " for compilation unit with index " +
 281                                  utostr(CUIndex));
 282
 283   ArrayRef<DWARFYAML::Abbrev> AbbrevDecls(
 284       DI.DebugAbbrev[AbbrevTableInfoOrErr->Index].Table);
 285
 286   if (AbbrCode > AbbrevDecls.size())
 287     return createStringError(
 288         errc::invalid_argument,
 289         "abbrev code must be less than or equal to the number of "
 290         "entries in abbreviation table");
 291   const DWARFYAML::Abbrev &Abbrev = AbbrevDecls[AbbrCode - 1];
 292   auto FormVal = Entry.Values.begin();
 293   auto AbbrForm = Abbrev.Attributes.begin();
 294   for (; FormVal != Entry.Values.end() && AbbrForm != Abbrev.Attributes.end();
 295        ++FormVal, ++AbbrForm) {
 296     dwarf::Form Form = AbbrForm->Form;
 297     bool Indirect;
 298     do {
 299       Indirect = false;
 300       switch (Form) {
 301       case dwarf::DW_FORM_addr:
 302         // TODO: Test this error.
 303         if (Error Err = writeVariableSizedInteger(
 304                 FormVal->Value, Params.AddrSize, OS, IsLittleEndian))
 305           return std::move(Err);
 306         break;
 307       case dwarf::DW_FORM_ref_addr:
 308         // TODO: Test this error.
 309         if (Error Err = writeVariableSizedInteger(FormVal->Value,
 310                                                   Params.getRefAddrByteSize(),
 311                                                   OS, IsLittleEndian))
 312           return std::move(Err);
 313         break;
 314       case dwarf::DW_FORM_exprloc:
 315       case dwarf::DW_FORM_block:
 316         encodeULEB128(FormVal->BlockData.size(), OS);
 317         OS.write((const char *)FormVal->BlockData.data(),
 318                  FormVal->BlockData.size());
 319         break;
 320       case dwarf::DW_FORM_block1: {
 321         writeInteger((uint8_t)FormVal->BlockData.size(), OS, IsLittleEndian);
 322         OS.write((const char *)FormVal->BlockData.data(),
 323                  FormVal->BlockData.size());
 324         break;
 325       }
 326       case dwarf::DW_FORM_block2: {
 327         writeInteger((uint16_t)FormVal->BlockData.size(), OS, IsLittleEndian);
 328         OS.write((const char *)FormVal->BlockData.data(),
 329                  FormVal->BlockData.size());
 330         break;
 331       }
 332       case dwarf::DW_FORM_block4: {
 333         writeInteger((uint32_t)FormVal->BlockData.size(), OS, IsLittleEndian);
 334         OS.write((const char *)FormVal->BlockData.data(),
 335                  FormVal->BlockData.size());
 336         break;
 337       }
 338       case dwarf::DW_FORM_strx:
 339       case dwarf::DW_FORM_addrx:
 340       case dwarf::DW_FORM_rnglistx:
 341       case dwarf::DW_FORM_loclistx:
 342       case dwarf::DW_FORM_udata:
 343       case dwarf::DW_FORM_ref_udata:
 344       case dwarf::DW_FORM_GNU_addr_index:
 345       case dwarf::DW_FORM_GNU_str_index:
 346         encodeULEB128(FormVal->Value, OS);
 347         break;
 348       case dwarf::DW_FORM_data1:
 349       case dwarf::DW_FORM_ref1:
 350       case dwarf::DW_FORM_flag:
 351       case dwarf::DW_FORM_strx1:
 352       case dwarf::DW_FORM_addrx1:
 353         writeInteger((uint8_t)FormVal->Value, OS, IsLittleEndian);
 354         break;
 355       case dwarf::DW_FORM_data2:
 356       case dwarf::DW_FORM_ref2:
 357       case dwarf::DW_FORM_strx2:
 358       case dwarf::DW_FORM_addrx2:
 359         writeInteger((uint16_t)FormVal->Value, OS, IsLittleEndian);
 360         break;
 361       case dwarf::DW_FORM_data4:
 362       case dwarf::DW_FORM_ref4:
 363       case dwarf::DW_FORM_ref_sup4:
 364       case dwarf::DW_FORM_strx4:
 365       case dwarf::DW_FORM_addrx4:
 366         writeInteger((uint32_t)FormVal->Value, OS, IsLittleEndian);
 367         break;
 368       case dwarf::DW_FORM_data8:
 369       case dwarf::DW_FORM_ref8:
 370       case dwarf::DW_FORM_ref_sup8:
 371       case dwarf::DW_FORM_ref_sig8:
 372         writeInteger((uint64_t)FormVal->Value, OS, IsLittleEndian);
 373         break;
 374       case dwarf::DW_FORM_sdata:
 375         encodeSLEB128(FormVal->Value, OS);
 376         break;
 377       case dwarf::DW_FORM_string:
 378         OS.write(FormVal->CStr.data(), FormVal->CStr.size());
 379         OS.write('\0');
 380         break;
 381       case dwarf::DW_FORM_indirect:
 382         encodeULEB128(FormVal->Value, OS);
 383         Indirect = true;
 384         Form = static_cast<dwarf::Form>((uint64_t)FormVal->Value);
 385         ++FormVal;
 386         break;
 387       case dwarf::DW_FORM_strp:
 388       case dwarf::DW_FORM_sec_offset:
 389       case dwarf::DW_FORM_GNU_ref_alt:
 390       case dwarf::DW_FORM_GNU_strp_alt:
 391       case dwarf::DW_FORM_line_strp:
 392       case dwarf::DW_FORM_strp_sup:
 393         cantFail(writeVariableSizedInteger(FormVal->Value,
 394                                            Params.getDwarfOffsetByteSize(), OS,
 395                                            IsLittleEndian));
 396         break;
 397       default:
 398         break;
 399       }
 400     } while (Indirect);
 401   }
 402
 403   return OS.tell() - EntryBegin;
 404 }
 405
 406 Error DWARFYAML::emitDebugInfo(raw_ostream &OS, const DWARFYAML::Data &DI) {
 407   for (uint64_t I = 0; I < DI.Units.size(); ++I) {
 408     const DWARFYAML::Unit &Unit = DI.Units[I];
 409     uint8_t AddrSize;
 410     if (Unit.AddrSize)
 411       AddrSize = *Unit.AddrSize;
 412     else
 413       AddrSize = DI.Is64BitAddrSize ? 8 : 4;
 414     dwarf::FormParams Params = {Unit.Version, AddrSize, Unit.Format};
 415     uint64_t Length = 3; // sizeof(version) + sizeof(address_size)
 416     Length += Params.getDwarfOffsetByteSize(); // sizeof(debug_abbrev_offset)
 417     if (Unit.Version >= 5) {
 418       ++Length; // sizeof(unit_type)
 419       switch (Unit.Type) {
 420       case dwarf::DW_UT_compile:
 421       case dwarf::DW_UT_partial:
 422       default:
 423         break;
 424       case dwarf::DW_UT_type:
 425       case dwarf::DW_UT_split_type:
 426         // sizeof(type_signature) + sizeof(type_offset)
 427         Length += 8 + Params.getDwarfOffsetByteSize();
 428         break;
 429       case dwarf::DW_UT_skeleton:
 430       case dwarf::DW_UT_split_compile:
 431         Length += 8; // sizeof(dwo_id)
 432       }
 433     }
 434
 435     // Since the length of the current compilation unit is undetermined yet, we
 436     // firstly write the content of the compilation unit to a buffer to
 437     // calculate it and then serialize the buffer content to the actual output
 438     // stream.
 439     std::string EntryBuffer;
 440     raw_string_ostream EntryBufferOS(EntryBuffer);
 441
 442     uint64_t AbbrevTableID = Unit.AbbrevTableID.value_or(I);
 443     for (const DWARFYAML::Entry &Entry : Unit.Entries) {
 444       if (Expected<uint64_t> EntryLength =
 445               writeDIE(DI, I, AbbrevTableID, Params, Entry, EntryBufferOS,
 446                        DI.IsLittleEndian))
 447         Length += *EntryLength;
 448       else
 449         return EntryLength.takeError();
 450     }
 451
 452     // If the length is specified in the YAML description, we use it instead of
 453     // the actual length.
 454     if (Unit.Length)
 455       Length = *Unit.Length;
 456
 457     writeInitialLength(Unit.Format, Length, OS, DI.IsLittleEndian);
 458     writeInteger((uint16_t)Unit.Version, OS, DI.IsLittleEndian);
 459
 460     uint64_t AbbrevTableOffset = 0;
 461     if (Unit.AbbrOffset) {
 462       AbbrevTableOffset = *Unit.AbbrOffset;
 463     } else {
 464       if (Expected<DWARFYAML::Data::AbbrevTableInfo> AbbrevTableInfoOrErr =
 465               DI.getAbbrevTableInfoByID(AbbrevTableID)) {
 466         AbbrevTableOffset = AbbrevTableInfoOrErr->Offset;
 467       } else {
 468         // The current compilation unit may not have DIEs and it will not be
 469         // able to find the associated abbrev table. We consume the error and
 470         // assign 0 to the debug_abbrev_offset in such circumstances.
 471         consumeError(AbbrevTableInfoOrErr.takeError());
 472       }
 473     }
 474
 475     if (Unit.Version >= 5) {
 476       writeInteger((uint8_t)Unit.Type, OS, DI.IsLittleEndian);
 477       writeInteger((uint8_t)AddrSize, OS, DI.IsLittleEndian);
 478       writeDWARFOffset(AbbrevTableOffset, Unit.Format, OS, DI.IsLittleEndian);
 479       switch (Unit.Type) {
 480       case dwarf::DW_UT_compile:
 481       case dwarf::DW_UT_partial:
 482       default:
 483         break;
 484       case dwarf::DW_UT_type:
 485       case dwarf::DW_UT_split_type:
 486         writeInteger(Unit.TypeSignatureOrDwoID, OS, DI.IsLittleEndian);
 487         writeDWARFOffset(Unit.TypeOffset, Unit.Format, OS, DI.IsLittleEndian);
 488         break;
 489       case dwarf::DW_UT_skeleton:
 490       case dwarf::DW_UT_split_compile:
 491         writeInteger(Unit.TypeSignatureOrDwoID, OS, DI.IsLittleEndian);
 492         break;
 493       }
 494     } else {
 495       writeDWARFOffset(AbbrevTableOffset, Unit.Format, OS, DI.IsLittleEndian);
 496       writeInteger((uint8_t)AddrSize, OS, DI.IsLittleEndian);
 497     }
 498
 499     OS.write(EntryBuffer.data(), EntryBuffer.size());
 500   }
 501
 502   return Error::success();
 503 }
 504
 505 static void emitFileEntry(raw_ostream &OS, const DWARFYAML::File &File) {
 506   OS.write(File.Name.data(), File.Name.size());
 507   OS.write('\0');
 508   encodeULEB128(File.DirIdx, OS);
 509   encodeULEB128(File.ModTime, OS);
 510   encodeULEB128(File.Length, OS);
 511 }
 512
 513 static void writeExtendedOpcode(const DWARFYAML::LineTableOpcode &Op,
 514                                 uint8_t AddrSize, bool IsLittleEndian,
 515                                 raw_ostream &OS) {
 516   // The first byte of extended opcodes is a zero byte. The next bytes are an
 517   // ULEB128 integer giving the number of bytes in the instruction itself (does
 518   // not include the first zero byte or the size). We serialize the instruction
 519   // itself into the OpBuffer and then write the size of the buffer and the
 520   // buffer to the real output stream.
 521   std::string OpBuffer;
 522   raw_string_ostream OpBufferOS(OpBuffer);
 523   writeInteger((uint8_t)Op.SubOpcode, OpBufferOS, IsLittleEndian);
 524   switch (Op.SubOpcode) {
 525   case dwarf::DW_LNE_set_address:
 526     cantFail(writeVariableSizedInteger(Op.Data, AddrSize, OpBufferOS,
 527                                        IsLittleEndian));
 528     break;
 529   case dwarf::DW_LNE_define_file:
 530     emitFileEntry(OpBufferOS, Op.FileEntry);
 531     break;
 532   case dwarf::DW_LNE_set_discriminator:
 533     encodeULEB128(Op.Data, OpBufferOS);
 534     break;
 535   case dwarf::DW_LNE_end_sequence:
 536     break;
 537   default:
 538     for (auto OpByte : Op.UnknownOpcodeData)
 539       writeInteger((uint8_t)OpByte, OpBufferOS, IsLittleEndian);
 540   }
 541   uint64_t ExtLen = Op.ExtLen.value_or(OpBuffer.size());
 542   encodeULEB128(ExtLen, OS);
 543   OS.write(OpBuffer.data(), OpBuffer.size());
 544 }
 545
 546 static void writeLineTableOpcode(const DWARFYAML::LineTableOpcode &Op,
 547                                  uint8_t OpcodeBase, uint8_t AddrSize,
 548                                  raw_ostream &OS, bool IsLittleEndian) {
 549   writeInteger((uint8_t)Op.Opcode, OS, IsLittleEndian);
 550   if (Op.Opcode == 0) {
 551     writeExtendedOpcode(Op, AddrSize, IsLittleEndian, OS);
 552   } else if (Op.Opcode < OpcodeBase) {
 553     switch (Op.Opcode) {
 554     case dwarf::DW_LNS_copy:
 555     case dwarf::DW_LNS_negate_stmt:
 556     case dwarf::DW_LNS_set_basic_block:
 557     case dwarf::DW_LNS_const_add_pc:
 558     case dwarf::DW_LNS_set_prologue_end:
 559     case dwarf::DW_LNS_set_epilogue_begin:
 560       break;
 561
 562     case dwarf::DW_LNS_advance_pc:
 563     case dwarf::DW_LNS_set_file:
 564     case dwarf::DW_LNS_set_column:
 565     case dwarf::DW_LNS_set_isa:
 566       encodeULEB128(Op.Data, OS);
 567       break;
 568
 569     case dwarf::DW_LNS_advance_line:
 570       encodeSLEB128(Op.SData, OS);
 571       break;
 572
 573     case dwarf::DW_LNS_fixed_advance_pc:
 574       writeInteger((uint16_t)Op.Data, OS, IsLittleEndian);
 575       break;
 576
 577     default:
 578       for (auto OpData : Op.StandardOpcodeData) {
 579         encodeULEB128(OpData, OS);
 580       }
 581     }
 582   }
 583 }
 584
 585 static std::vector<uint8_t>
 586 getStandardOpcodeLengths(uint16_t Version, std::optional<uint8_t> OpcodeBase) {
 587   // If the opcode_base field isn't specified, we returns the
 588   // standard_opcode_lengths array according to the version by default.
 589   std::vector<uint8_t> StandardOpcodeLengths{0, 1, 1, 1, 1, 0,
 590                                              0, 0, 1, 0, 0, 1};
 591   if (Version == 2) {
 592     // DWARF v2 uses the same first 9 standard opcodes as v3-5.
 593     StandardOpcodeLengths.resize(9);
 594   } else if (OpcodeBase) {
 595     StandardOpcodeLengths.resize(*OpcodeBase > 0 ? *OpcodeBase - 1 : 0, 0);
 596   }
 597   return StandardOpcodeLengths;
 598 }
 599
 600 Error DWARFYAML::emitDebugLine(raw_ostream &OS, const DWARFYAML::Data &DI) {
 601   for (const DWARFYAML::LineTable &LineTable : DI.DebugLines) {
 602     // Buffer holds the bytes following the header_length (or prologue_length in
 603     // DWARFv2) field to the end of the line number program itself.
 604     std::string Buffer;
 605     raw_string_ostream BufferOS(Buffer);
 606
 607     writeInteger(LineTable.MinInstLength, BufferOS, DI.IsLittleEndian);
 608     // TODO: Add support for emitting DWARFv5 line table.
 609     if (LineTable.Version >= 4)
 610       writeInteger(LineTable.MaxOpsPerInst, BufferOS, DI.IsLittleEndian);
 611     writeInteger(LineTable.DefaultIsStmt, BufferOS, DI.IsLittleEndian);
 612     writeInteger(LineTable.LineBase, BufferOS, DI.IsLittleEndian);
 613     writeInteger(LineTable.LineRange, BufferOS, DI.IsLittleEndian);
 614
 615     std::vector<uint8_t> StandardOpcodeLengths =
 616         LineTable.StandardOpcodeLengths.value_or(
 617             getStandardOpcodeLengths(LineTable.Version, LineTable.OpcodeBase));
 618     uint8_t OpcodeBase = LineTable.OpcodeBase
 619                              ? *LineTable.OpcodeBase
 620                              : StandardOpcodeLengths.size() + 1;
 621     writeInteger(OpcodeBase, BufferOS, DI.IsLittleEndian);
 622     for (uint8_t OpcodeLength : StandardOpcodeLengths)
 623       writeInteger(OpcodeLength, BufferOS, DI.IsLittleEndian);
 624
 625     for (StringRef IncludeDir : LineTable.IncludeDirs) {
 626       BufferOS.write(IncludeDir.data(), IncludeDir.size());
 627       BufferOS.write('\0');
 628     }
 629     BufferOS.write('\0');
 630
 631     for (const DWARFYAML::File &File : LineTable.Files)
 632       emitFileEntry(BufferOS, File);
 633     BufferOS.write('\0');
 634
 635     uint64_t HeaderLength =
 636         LineTable.PrologueLength ? *LineTable.PrologueLength : Buffer.size();
 637
 638     for (const DWARFYAML::LineTableOpcode &Op : LineTable.Opcodes)
 639       writeLineTableOpcode(Op, OpcodeBase, DI.Is64BitAddrSize ? 8 : 4, BufferOS,
 640                            DI.IsLittleEndian);
 641
 642     uint64_t Length;
 643     if (LineTable.Length) {
 644       Length = *LineTable.Length;
 645     } else {
 646       Length = 2; // sizeof(version)
 647       Length +=
 648           (LineTable.Format == dwarf::DWARF64 ? 8 : 4); // sizeof(header_length)
 649       Length += Buffer.size();
 650     }
 651
 652     writeInitialLength(LineTable.Format, Length, OS, DI.IsLittleEndian);
 653     writeInteger(LineTable.Version, OS, DI.IsLittleEndian);
 654     writeDWARFOffset(HeaderLength, LineTable.Format, OS, DI.IsLittleEndian);
 655     OS.write(Buffer.data(), Buffer.size());
 656   }
 657
 658   return Error::success();
 659 }
 660
 661 Error DWARFYAML::emitDebugAddr(raw_ostream &OS, const Data &DI) {
 662   for (const AddrTableEntry &TableEntry : *DI.DebugAddr) {
 663     uint8_t AddrSize;
 664     if (TableEntry.AddrSize)
 665       AddrSize = *TableEntry.AddrSize;
 666     else
 667       AddrSize = DI.Is64BitAddrSize ? 8 : 4;
 668
 669     uint64_t Length;
 670     if (TableEntry.Length)
 671       Length = (uint64_t)*TableEntry.Length;
 672     else
 673       // 2 (version) + 1 (address_size) + 1 (segment_selector_size) = 4
 674       Length = 4 + (AddrSize + TableEntry.SegSelectorSize) *
 675                        TableEntry.SegAddrPairs.size();
 676
 677     writeInitialLength(TableEntry.Format, Length, OS, DI.IsLittleEndian);
 678     writeInteger((uint16_t)TableEntry.Version, OS, DI.IsLittleEndian);
 679     writeInteger((uint8_t)AddrSize, OS, DI.IsLittleEndian);
 680     writeInteger((uint8_t)TableEntry.SegSelectorSize, OS, DI.IsLittleEndian);
 681
 682     for (const SegAddrPair &Pair : TableEntry.SegAddrPairs) {
 683       if (TableEntry.SegSelectorSize != yaml::Hex8{0})
 684         if (Error Err = writeVariableSizedInteger(Pair.Segment,
 685                                                   TableEntry.SegSelectorSize,
 686                                                   OS, DI.IsLittleEndian))
 687           return createStringError(errc::not_supported,
 688                                    "unable to write debug_addr segment: %s",
 689                                    toString(std::move(Err)).c_str());
 690       if (AddrSize != 0)
 691         if (Error Err = writeVariableSizedInteger(Pair.Address, AddrSize, OS,
 692                                                   DI.IsLittleEndian))
 693           return createStringError(errc::not_supported,
 694                                    "unable to write debug_addr address: %s",
 695                                    toString(std::move(Err)).c_str());
 696     }
 697   }
 698
 699   return Error::success();
 700 }
 701
 702 Error DWARFYAML::emitDebugStrOffsets(raw_ostream &OS, const Data &DI) {
 703   assert(DI.DebugStrOffsets && "unexpected emitDebugStrOffsets() call");
 704   for (const DWARFYAML::StringOffsetsTable &Table : *DI.DebugStrOffsets) {
 705     uint64_t Length;
 706     if (Table.Length)
 707       Length = *Table.Length;
 708     else
 709       // sizeof(version) + sizeof(padding) = 4
 710       Length =
 711           4 + Table.Offsets.size() * (Table.Format == dwarf::DWARF64 ? 8 : 4);
 712
 713     writeInitialLength(Table.Format, Length, OS, DI.IsLittleEndian);
 714     writeInteger((uint16_t)Table.Version, OS, DI.IsLittleEndian);
 715     writeInteger((uint16_t)Table.Padding, OS, DI.IsLittleEndian);
 716
 717     for (uint64_t Offset : Table.Offsets)
 718       writeDWARFOffset(Offset, Table.Format, OS, DI.IsLittleEndian);
 719   }
 720
 721   return Error::success();
 722 }
 723
 724 namespace {
 725 /// Emits the header for a DebugNames section.
 726 void emitDebugNamesHeader(raw_ostream &OS, bool IsLittleEndian,
 727                           uint32_t NameCount, uint32_t AbbrevSize,
 728                           uint32_t CombinedSizeOtherParts) {
 729   // Use the same AugmentationString as AsmPrinter.
 730   StringRef AugmentationString = "LLVM0700";
 731   size_t TotalSize = CombinedSizeOtherParts + 5 * sizeof(uint32_t) +
 732                      2 * sizeof(uint16_t) + sizeof(NameCount) +
 733                      sizeof(AbbrevSize) + AugmentationString.size();
 734   writeInteger(uint32_t(TotalSize), OS, IsLittleEndian); // Unit length
 735
 736   // Everything below is included in total size.
 737   writeInteger(uint16_t(5), OS, IsLittleEndian); // Version
 738   writeInteger(uint16_t(0), OS, IsLittleEndian); // Padding
 739   writeInteger(uint32_t(1), OS, IsLittleEndian); // Compilation Unit count
 740   writeInteger(uint32_t(0), OS, IsLittleEndian); // Local Type Unit count
 741   writeInteger(uint32_t(0), OS, IsLittleEndian); // Foreign Type Unit count
 742   writeInteger(uint32_t(0), OS, IsLittleEndian); // Bucket count
 743   writeInteger(NameCount, OS, IsLittleEndian);
 744   writeInteger(AbbrevSize, OS, IsLittleEndian);
 745   writeInteger(uint32_t(AugmentationString.size()), OS, IsLittleEndian);
 746   OS.write(AugmentationString.data(), AugmentationString.size());
 747 }
 748
 749 /// Emits the abbreviations for a DebugNames section.
 750 std::string
 751 emitDebugNamesAbbrev(ArrayRef<DWARFYAML::DebugNameAbbreviation> Abbrevs) {
 752   std::string Data;
 753   raw_string_ostream OS(Data);
 754   for (const DWARFYAML::DebugNameAbbreviation &Abbrev : Abbrevs) {
 755     encodeULEB128(Abbrev.Code, OS);
 756     encodeULEB128(Abbrev.Tag, OS);
 757     for (auto [Idx, Form] : Abbrev.Indices) {
 758       encodeULEB128(Idx, OS);
 759       encodeULEB128(Form, OS);
 760     }
 761     encodeULEB128(0, OS);
 762     encodeULEB128(0, OS);
 763   }
 764   encodeULEB128(0, OS);
 765   return Data;
 766 }
 767
 768 /// Emits a simple CU offsets list for a DebugNames section containing a single
 769 /// CU at offset 0.
 770 std::string emitDebugNamesCUOffsets(bool IsLittleEndian) {
 771   std::string Data;
 772   raw_string_ostream OS(Data);
 773   writeInteger(uint32_t(0), OS, IsLittleEndian);
 774   return Data;
 775 }
 776
 777 /// Emits the "NameTable" for a DebugNames section; according to the spec, it
 778 /// consists of two arrays: an array of string offsets, followed immediately by
 779 /// an array of entry offsets. The string offsets are emitted in the order
 780 /// provided in `Entries`.
 781 std::string emitDebugNamesNameTable(
 782     bool IsLittleEndian,
 783     const DenseMap<uint32_t, std::vector<DWARFYAML::DebugNameEntry>> &Entries,
 784     ArrayRef<uint32_t> EntryPoolOffsets) {
 785   assert(Entries.size() == EntryPoolOffsets.size());
 786
 787   std::string Data;
 788   raw_string_ostream OS(Data);
 789
 790   for (uint32_t Strp : make_first_range(Entries))
 791     writeInteger(Strp, OS, IsLittleEndian);
 792   for (uint32_t PoolOffset : EntryPoolOffsets)
 793     writeInteger(PoolOffset, OS, IsLittleEndian);
 794   return Data;
 795 }
 796
 797 /// Groups entries based on their name (strp) code and returns a map.
 798 DenseMap<uint32_t, std::vector<DWARFYAML::DebugNameEntry>>
 799 groupEntries(ArrayRef<DWARFYAML::DebugNameEntry> Entries) {
 800   DenseMap<uint32_t, std::vector<DWARFYAML::DebugNameEntry>> StrpToEntries;
 801   for (const DWARFYAML::DebugNameEntry &Entry : Entries)
 802     StrpToEntries[Entry.NameStrp].push_back(Entry);
 803   return StrpToEntries;
 804 }
 805
 806 /// Finds the abbreviation whose code is AbbrevCode and returns a list
 807 /// containing the expected size of all non-zero-length forms.
 808 Expected<SmallVector<uint8_t>>
 809 getNonZeroDataSizesFor(uint32_t AbbrevCode,
 810                        ArrayRef<DWARFYAML::DebugNameAbbreviation> Abbrevs) {
 811   const auto *AbbrevIt = find_if(Abbrevs, [&](const auto &Abbrev) {
 812     return Abbrev.Code.value == AbbrevCode;
 813   });
 814   if (AbbrevIt == Abbrevs.end())
 815     return createStringError(inconvertibleErrorCode(),
 816                              "did not find an Abbreviation for this code");
 817
 818   SmallVector<uint8_t> DataSizes;
 819   dwarf::FormParams Params{/*Version=*/5, /*AddrSize=*/4, dwarf::DWARF32};
 820   for (auto [Idx, Form] : AbbrevIt->Indices) {
 821     std::optional<uint8_t> FormSize = dwarf::getFixedFormByteSize(Form, Params);
 822     if (!FormSize)
 823       return createStringError(inconvertibleErrorCode(),
 824                                "unsupported Form for YAML debug_names emitter");
 825     if (FormSize == 0)
 826       continue;
 827     DataSizes.push_back(*FormSize);
 828   }
 829   return DataSizes;
 830 }
 831
 832 struct PoolOffsetsAndData {
 833   std::string PoolData;
 834   std::vector<uint32_t> PoolOffsets;
 835 };
 836
 837 /// Emits the entry pool and returns an array of offsets containing the start
 838 /// offset for the entries of each unique name.
 839 /// Verifies that the provided number of data values match those expected by
 840 /// the abbreviation table.
 841 Expected<PoolOffsetsAndData> emitDebugNamesEntryPool(
 842     bool IsLittleEndian,
 843     const DenseMap<uint32_t, std::vector<DWARFYAML::DebugNameEntry>>
 844         &StrpToEntries,
 845     ArrayRef<DWARFYAML::DebugNameAbbreviation> Abbrevs) {
 846   PoolOffsetsAndData Result;
 847   raw_string_ostream OS(Result.PoolData);
 848
 849   for (ArrayRef<DWARFYAML::DebugNameEntry> EntriesWithSameName :
 850        make_second_range(StrpToEntries)) {
 851     Result.PoolOffsets.push_back(Result.PoolData.size());
 852
 853     for (const DWARFYAML::DebugNameEntry &Entry : EntriesWithSameName) {
 854       encodeULEB128(Entry.Code, OS);
 855
 856       Expected<SmallVector<uint8_t>> DataSizes =
 857           getNonZeroDataSizesFor(Entry.Code, Abbrevs);
 858       if (!DataSizes)
 859         return DataSizes.takeError();
 860       if (DataSizes->size() != Entry.Values.size())
 861         return createStringError(
 862             inconvertibleErrorCode(),
 863             "mismatch between provided and required number of values");
 864
 865       for (auto [Value, ValueSize] : zip_equal(Entry.Values, *DataSizes))
 866         if (Error E =
 867                 writeVariableSizedInteger(Value, ValueSize, OS, IsLittleEndian))
 868           return std::move(E);
 869     }
 870     encodeULEB128(0, OS);
 871   }
 872
 873   return Result;
 874 }
 875 } // namespace
 876
 877 Error DWARFYAML::emitDebugNames(raw_ostream &OS, const Data &DI) {
 878   assert(DI.DebugNames && "unexpected emitDebugNames() call");
 879   const DebugNamesSection DebugNames = DI.DebugNames.value();
 880
 881   DenseMap<uint32_t, std::vector<DebugNameEntry>> StrpToEntries =
 882       groupEntries(DebugNames.Entries);
 883
 884   // Emit all sub-sections into individual strings so that we may compute
 885   // relative offsets and sizes.
 886   Expected<PoolOffsetsAndData> PoolInfo = emitDebugNamesEntryPool(
 887       DI.IsLittleEndian, StrpToEntries, DebugNames.Abbrevs);
 888   if (!PoolInfo)
 889     return PoolInfo.takeError();
 890   std::string NamesTableData = emitDebugNamesNameTable(
 891       DI.IsLittleEndian, StrpToEntries, PoolInfo->PoolOffsets);
 892
 893   std::string AbbrevData = emitDebugNamesAbbrev(DebugNames.Abbrevs);
 894   std::string CUOffsetsData = emitDebugNamesCUOffsets(DI.IsLittleEndian);
 895
 896   size_t TotalSize = PoolInfo->PoolData.size() + NamesTableData.size() +
 897                      AbbrevData.size() + CUOffsetsData.size();
 898
 899   // Start real emission by combining all individual strings.
 900   emitDebugNamesHeader(OS, DI.IsLittleEndian, StrpToEntries.size(),
 901                        AbbrevData.size(), TotalSize);
 902   OS.write(CUOffsetsData.data(), CUOffsetsData.size());
 903   // No local TUs, no foreign TUs, no hash lookups table.
 904   OS.write(NamesTableData.data(), NamesTableData.size());
 905   OS.write(AbbrevData.data(), AbbrevData.size());
 906   OS.write(PoolInfo->PoolData.data(), PoolInfo->PoolData.size());
 907
 908   return Error::success();
 909 }
 910
 911 static Error checkOperandCount(StringRef EncodingString,
 912                                ArrayRef<yaml::Hex64> Values,
 913                                uint64_t ExpectedOperands) {
 914   if (Values.size() != ExpectedOperands)
 915     return createStringError(
 916         errc::invalid_argument,
 917         "invalid number (%zu) of operands for the operator: %s, %" PRIu64
 918         " expected",
 919         Values.size(), EncodingString.str().c_str(), ExpectedOperands);
 920
 921   return Error::success();
 922 }
 923
 924 static Error writeListEntryAddress(StringRef EncodingName, raw_ostream &OS,
 925                                    uint64_t Addr, uint8_t AddrSize,
 926                                    bool IsLittleEndian) {
 927   if (Error Err = writeVariableSizedInteger(Addr, AddrSize, OS, IsLittleEndian))
 928     return createStringError(errc::invalid_argument,
 929                              "unable to write address for the operator %s: %s",
 930                              EncodingName.str().c_str(),
 931                              toString(std::move(Err)).c_str());
 932
 933   return Error::success();
 934 }
 935
 936 static Expected<uint64_t>
 937 writeDWARFExpression(raw_ostream &OS,
 938                      const DWARFYAML::DWARFOperation &Operation,
 939                      uint8_t AddrSize, bool IsLittleEndian) {
 940   auto CheckOperands = [&](uint64_t ExpectedOperands) -> Error {
 941     return checkOperandCount(dwarf::OperationEncodingString(Operation.Operator),
 942                              Operation.Values, ExpectedOperands);
 943   };
 944
 945   uint64_t ExpressionBegin = OS.tell();
 946   writeInteger((uint8_t)Operation.Operator, OS, IsLittleEndian);
 947   switch (Operation.Operator) {
 948   case dwarf::DW_OP_consts:
 949     if (Error Err = CheckOperands(1))
 950       return std::move(Err);
 951     encodeSLEB128(Operation.Values[0], OS);
 952     break;
 953   case dwarf::DW_OP_stack_value:
 954     if (Error Err = CheckOperands(0))
 955       return std::move(Err);
 956     break;
 957   default:
 958     StringRef EncodingStr = dwarf::OperationEncodingString(Operation.Operator);
 959     return createStringError(errc::not_supported,
 960                              "DWARF expression: " +
 961                                  (EncodingStr.empty()
 962                                       ? "0x" + utohexstr(Operation.Operator)
 963                                       : EncodingStr) +
 964                                  " is not supported");
 965   }
 966   return OS.tell() - ExpressionBegin;
 967 }
 968
 969 static Expected<uint64_t> writeListEntry(raw_ostream &OS,
 970                                          const DWARFYAML::RnglistEntry &Entry,
 971                                          uint8_t AddrSize,
 972                                          bool IsLittleEndian) {
 973   uint64_t BeginOffset = OS.tell();
 974   writeInteger((uint8_t)Entry.Operator, OS, IsLittleEndian);
 975
 976   StringRef EncodingName = dwarf::RangeListEncodingString(Entry.Operator);
 977
 978   auto CheckOperands = [&](uint64_t ExpectedOperands) -> Error {
 979     return checkOperandCount(EncodingName, Entry.Values, ExpectedOperands);
 980   };
 981
 982   auto WriteAddress = [&](uint64_t Addr) -> Error {
 983     return writeListEntryAddress(EncodingName, OS, Addr, AddrSize,
 984                                  IsLittleEndian);
 985   };
 986
 987   switch (Entry.Operator) {
 988   case dwarf::DW_RLE_end_of_list:
 989     if (Error Err = CheckOperands(0))
 990       return std::move(Err);
 991     break;
 992   case dwarf::DW_RLE_base_addressx:
 993     if (Error Err = CheckOperands(1))
 994       return std::move(Err);
 995     encodeULEB128(Entry.Values[0], OS);
 996     break;
 997   case dwarf::DW_RLE_startx_endx:
 998   case dwarf::DW_RLE_startx_length:
 999   case dwarf::DW_RLE_offset_pair:
1000     if (Error Err = CheckOperands(2))
1001       return std::move(Err);
1002     encodeULEB128(Entry.Values[0], OS);
1003     encodeULEB128(Entry.Values[1], OS);
1004     break;
1005   case dwarf::DW_RLE_base_address:
1006     if (Error Err = CheckOperands(1))
1007       return std::move(Err);
1008     if (Error Err = WriteAddress(Entry.Values[0]))
1009       return std::move(Err);
1010     break;
1011   case dwarf::DW_RLE_start_end:
1012     if (Error Err = CheckOperands(2))
1013       return std::move(Err);
1014     if (Error Err = WriteAddress(Entry.Values[0]))
1015       return std::move(Err);
1016     cantFail(WriteAddress(Entry.Values[1]));
1017     break;
1018   case dwarf::DW_RLE_start_length:
1019     if (Error Err = CheckOperands(2))
1020       return std::move(Err);
1021     if (Error Err = WriteAddress(Entry.Values[0]))
1022       return std::move(Err);
1023     encodeULEB128(Entry.Values[1], OS);
1024     break;
1025   }
1026
1027   return OS.tell() - BeginOffset;
1028 }
1029
1030 static Expected<uint64_t> writeListEntry(raw_ostream &OS,
1031                                          const DWARFYAML::LoclistEntry &Entry,
1032                                          uint8_t AddrSize,
1033                                          bool IsLittleEndian) {
1034   uint64_t BeginOffset = OS.tell();
1035   writeInteger((uint8_t)Entry.Operator, OS, IsLittleEndian);
1036
1037   StringRef EncodingName = dwarf::LocListEncodingString(Entry.Operator);
1038
1039   auto CheckOperands = [&](uint64_t ExpectedOperands) -> Error {
1040     return checkOperandCount(EncodingName, Entry.Values, ExpectedOperands);
1041   };
1042
1043   auto WriteAddress = [&](uint64_t Addr) -> Error {
1044     return writeListEntryAddress(EncodingName, OS, Addr, AddrSize,
1045                                  IsLittleEndian);
1046   };
1047
1048   auto WriteDWARFOperations = [&]() -> Error {
1049     std::string OpBuffer;
1050     raw_string_ostream OpBufferOS(OpBuffer);
1051     uint64_t DescriptionsLength = 0;
1052
1053     for (const DWARFYAML::DWARFOperation &Op : Entry.Descriptions) {
1054       if (Expected<uint64_t> OpSize =
1055               writeDWARFExpression(OpBufferOS, Op, AddrSize, IsLittleEndian))
1056         DescriptionsLength += *OpSize;
1057       else
1058         return OpSize.takeError();
1059     }
1060
1061     if (Entry.DescriptionsLength)
1062       DescriptionsLength = *Entry.DescriptionsLength;
1063     else
1064       DescriptionsLength = OpBuffer.size();
1065
1066     encodeULEB128(DescriptionsLength, OS);
1067     OS.write(OpBuffer.data(), OpBuffer.size());
1068
1069     return Error::success();
1070   };
1071
1072   switch (Entry.Operator) {
1073   case dwarf::DW_LLE_end_of_list:
1074     if (Error Err = CheckOperands(0))
1075       return std::move(Err);
1076     break;
1077   case dwarf::DW_LLE_base_addressx:
1078     if (Error Err = CheckOperands(1))
1079       return std::move(Err);
1080     encodeULEB128(Entry.Values[0], OS);
1081     break;
1082   case dwarf::DW_LLE_startx_endx:
1083   case dwarf::DW_LLE_startx_length:
1084   case dwarf::DW_LLE_offset_pair:
1085     if (Error Err = CheckOperands(2))
1086       return std::move(Err);
1087     encodeULEB128(Entry.Values[0], OS);
1088     encodeULEB128(Entry.Values[1], OS);
1089     if (Error Err = WriteDWARFOperations())
1090       return std::move(Err);
1091     break;
1092   case dwarf::DW_LLE_default_location:
1093     if (Error Err = CheckOperands(0))
1094       return std::move(Err);
1095     if (Error Err = WriteDWARFOperations())
1096       return std::move(Err);
1097     break;
1098   case dwarf::DW_LLE_base_address:
1099     if (Error Err = CheckOperands(1))
1100       return std::move(Err);
1101     if (Error Err = WriteAddress(Entry.Values[0]))
1102       return std::move(Err);
1103     break;
1104   case dwarf::DW_LLE_start_end:
1105     if (Error Err = CheckOperands(2))
1106       return std::move(Err);
1107     if (Error Err = WriteAddress(Entry.Values[0]))
1108       return std::move(Err);
1109     cantFail(WriteAddress(Entry.Values[1]));
1110     if (Error Err = WriteDWARFOperations())
1111       return std::move(Err);
1112     break;
1113   case dwarf::DW_LLE_start_length:
1114     if (Error Err = CheckOperands(2))
1115       return std::move(Err);
1116     if (Error Err = WriteAddress(Entry.Values[0]))
1117       return std::move(Err);
1118     encodeULEB128(Entry.Values[1], OS);
1119     if (Error Err = WriteDWARFOperations())
1120       return std::move(Err);
1121     break;
1122   }
1123
1124   return OS.tell() - BeginOffset;
1125 }
1126
1127 template <typename EntryType>
1128 static Error writeDWARFLists(raw_ostream &OS,
1129                              ArrayRef<DWARFYAML::ListTable<EntryType>> Tables,
1130                              bool IsLittleEndian, bool Is64BitAddrSize) {
1131   for (const DWARFYAML::ListTable<EntryType> &Table : Tables) {
1132     // sizeof(version) + sizeof(address_size) + sizeof(segment_selector_size) +
1133     // sizeof(offset_entry_count) = 8
1134     uint64_t Length = 8;
1135
1136     uint8_t AddrSize;
1137     if (Table.AddrSize)
1138       AddrSize = *Table.AddrSize;
1139     else
1140       AddrSize = Is64BitAddrSize ? 8 : 4;
1141
1142     // Since the length of the current range/location lists entry is
1143     // undetermined yet, we firstly write the content of the range/location
1144     // lists to a buffer to calculate the length and then serialize the buffer
1145     // content to the actual output stream.
1146     std::string ListBuffer;
1147     raw_string_ostream ListBufferOS(ListBuffer);
1148
1149     // Offsets holds offsets for each range/location list. The i-th element is
1150     // the offset from the beginning of the first range/location list to the
1151     // location of the i-th range list.
1152     std::vector<uint64_t> Offsets;
1153
1154     for (const DWARFYAML::ListEntries<EntryType> &List : Table.Lists) {
1155       Offsets.push_back(ListBufferOS.tell());
1156       if (List.Content) {
1157         List.Content->writeAsBinary(ListBufferOS, UINT64_MAX);
1158         Length += List.Content->binary_size();
1159       } else if (List.Entries) {
1160         for (const EntryType &Entry : *List.Entries) {
1161           Expected<uint64_t> EntrySize =
1162               writeListEntry(ListBufferOS, Entry, AddrSize, IsLittleEndian);
1163           if (!EntrySize)
1164             return EntrySize.takeError();
1165           Length += *EntrySize;
1166         }
1167       }
1168     }
1169
1170     // If the offset_entry_count field isn't specified, yaml2obj will infer it
1171     // from the 'Offsets' field in the YAML description. If the 'Offsets' field
1172     // isn't specified either, yaml2obj will infer it from the auto-generated
1173     // offsets.
1174     uint32_t OffsetEntryCount;
1175     if (Table.OffsetEntryCount)
1176       OffsetEntryCount = *Table.OffsetEntryCount;
1177     else
1178       OffsetEntryCount = Table.Offsets ? Table.Offsets->size() : Offsets.size();
1179     uint64_t OffsetsSize =
1180         OffsetEntryCount * (Table.Format == dwarf::DWARF64 ? 8 : 4);
1181     Length += OffsetsSize;
1182
1183     // If the length is specified in the YAML description, we use it instead of
1184     // the actual length.
1185     if (Table.Length)
1186       Length = *Table.Length;
1187
1188     writeInitialLength(Table.Format, Length, OS, IsLittleEndian);
1189     writeInteger((uint16_t)Table.Version, OS, IsLittleEndian);
1190     writeInteger((uint8_t)AddrSize, OS, IsLittleEndian);
1191     writeInteger((uint8_t)Table.SegSelectorSize, OS, IsLittleEndian);
1192     writeInteger((uint32_t)OffsetEntryCount, OS, IsLittleEndian);
1193
1194     auto EmitOffsets = [&](ArrayRef<uint64_t> Offsets, uint64_t OffsetsSize) {
1195       for (uint64_t Offset : Offsets)
1196         writeDWARFOffset(OffsetsSize + Offset, Table.Format, OS,
1197                          IsLittleEndian);
1198     };
1199
1200     if (Table.Offsets)
1201       EmitOffsets(ArrayRef<uint64_t>((const uint64_t *)Table.Offsets->data(),
1202                                      Table.Offsets->size()),
1203                   0);
1204     else if (OffsetEntryCount != 0)
1205       EmitOffsets(Offsets, OffsetsSize);
1206
1207     OS.write(ListBuffer.data(), ListBuffer.size());
1208   }
1209
1210   return Error::success();
1211 }
1212
1213 Error DWARFYAML::emitDebugRnglists(raw_ostream &OS, const Data &DI) {
1214   assert(DI.DebugRnglists && "unexpected emitDebugRnglists() call");
1215   return writeDWARFLists<DWARFYAML::RnglistEntry>(
1216       OS, *DI.DebugRnglists, DI.IsLittleEndian, DI.Is64BitAddrSize);
1217 }
1218
1219 Error DWARFYAML::emitDebugLoclists(raw_ostream &OS, const Data &DI) {
1220   assert(DI.DebugLoclists && "unexpected emitDebugRnglists() call");
1221   return writeDWARFLists<DWARFYAML::LoclistEntry>(
1222       OS, *DI.DebugLoclists, DI.IsLittleEndian, DI.Is64BitAddrSize);
1223 }
1224
1225 std::function<Error(raw_ostream &, const DWARFYAML::Data &)>
1226 DWARFYAML::getDWARFEmitterByName(StringRef SecName) {
1227   auto EmitFunc =
1228       StringSwitch<
1229           std::function<Error(raw_ostream &, const DWARFYAML::Data &)>>(SecName)
1230           .Case("debug_abbrev", DWARFYAML::emitDebugAbbrev)
1231           .Case("debug_addr", DWARFYAML::emitDebugAddr)
1232           .Case("debug_aranges", DWARFYAML::emitDebugAranges)
1233           .Case("debug_gnu_pubnames", DWARFYAML::emitDebugGNUPubnames)
1234           .Case("debug_gnu_pubtypes", DWARFYAML::emitDebugGNUPubtypes)
1235           .Case("debug_info", DWARFYAML::emitDebugInfo)
1236           .Case("debug_line", DWARFYAML::emitDebugLine)
1237           .Case("debug_loclists", DWARFYAML::emitDebugLoclists)
1238           .Case("debug_pubnames", DWARFYAML::emitDebugPubnames)
1239           .Case("debug_pubtypes", DWARFYAML::emitDebugPubtypes)
1240           .Case("debug_ranges", DWARFYAML::emitDebugRanges)
1241           .Case("debug_rnglists", DWARFYAML::emitDebugRnglists)
1242           .Case("debug_str", DWARFYAML::emitDebugStr)
1243           .Case("debug_str_offsets", DWARFYAML::emitDebugStrOffsets)
1244           .Case("debug_names", DWARFYAML::emitDebugNames)
1245           .Default([&](raw_ostream &, const DWARFYAML::Data &) {
1246             return createStringError(errc::not_supported,
1247                                      SecName + " is not supported");
1248           });
1249
1250   return EmitFunc;
1251 }
1252
1253 static Error
1254 emitDebugSectionImpl(const DWARFYAML::Data &DI, StringRef Sec,
1255                      StringMap<std::unique_ptr<MemoryBuffer>> &OutputBuffers) {
1256   std::string Data;
1257   raw_string_ostream DebugInfoStream(Data);
1258
1259   auto EmitFunc = DWARFYAML::getDWARFEmitterByName(Sec);
1260
1261   if (Error Err = EmitFunc(DebugInfoStream, DI))
1262     return Err;
1263   DebugInfoStream.flush();
1264   if (!Data.empty())
1265     OutputBuffers[Sec] = MemoryBuffer::getMemBufferCopy(Data);
1266
1267   return Error::success();
1268 }
1269
1270 Expected<StringMap<std::unique_ptr<MemoryBuffer>>>
1271 DWARFYAML::emitDebugSections(StringRef YAMLString, bool IsLittleEndian,
1272                              bool Is64BitAddrSize) {
1273   auto CollectDiagnostic = [](const SMDiagnostic &Diag, void *DiagContext) {
1274     *static_cast<SMDiagnostic *>(DiagContext) = Diag;
1275   };
1276
1277   SMDiagnostic GeneratedDiag;
1278   yaml::Input YIn(YAMLString, /*Ctxt=*/nullptr, CollectDiagnostic,
1279                   &GeneratedDiag);
1280
1281   DWARFYAML::Data DI;
1282   DI.IsLittleEndian = IsLittleEndian;
1283   DI.Is64BitAddrSize = Is64BitAddrSize;
1284
1285   YIn >> DI;
1286   if (YIn.error())
1287     return createStringError(YIn.error(), GeneratedDiag.getMessage());
1288
1289   StringMap<std::unique_ptr<MemoryBuffer>> DebugSections;
1290   Error Err = Error::success();
1291
1292   for (StringRef SecName : DI.getNonEmptySectionNames())
1293     Err = joinErrors(std::move(Err),
1294                      emitDebugSectionImpl(DI, SecName, DebugSections));
1295
1296   if (Err)
1297     return std::move(Err);
1298   return std::move(DebugSections);
1299 }