xref: /freebsd/contrib/llvm-project/llvm/lib/DWP/DWP.cpp (revision fcaf7f8644a9988098ac6be2165bce3ea4786e91) 
1 //===-- llvm-dwp.cpp - Split DWARF merging tool for llvm ------------------===//
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 // A utility for merging DWARF 5 Split DWARF .dwo files into .dwp (DWARF
10 // package files).
11 //
12 //===----------------------------------------------------------------------===//
13 #include "llvm/DWP/DWP.h"
14 #include "llvm/DWP/DWPError.h"
15 #include "llvm/MC/MCContext.h"
16 #include "llvm/MC/MCObjectFileInfo.h"
17 #include "llvm/MC/MCTargetOptionsCommandFlags.h"
18 #include "llvm/Object/Decompressor.h"
19 #include "llvm/Object/ELFObjectFile.h"
20 #include "llvm/Support/MemoryBuffer.h"
21 
22 using namespace llvm;
23 using namespace llvm::object;
24 
25 static mc::RegisterMCTargetOptionsFlags MCTargetOptionsFlags;
26 
27 // Returns the size of debug_str_offsets section headers in bytes.
28 static uint64_t debugStrOffsetsHeaderSize(DataExtractor StrOffsetsData,
29                                           uint16_t DwarfVersion) {
30   if (DwarfVersion <= 4)
31     return 0; // There is no header before dwarf 5.
32   uint64_t Offset = 0;
33   uint64_t Length = StrOffsetsData.getU32(&Offset);
34   if (Length == llvm::dwarf::DW_LENGTH_DWARF64)
35     return 16; // unit length: 12 bytes, version: 2 bytes, padding: 2 bytes.
36   return 8;    // unit length: 4 bytes, version: 2 bytes, padding: 2 bytes.
37 }
38 
39 static uint64_t getCUAbbrev(StringRef Abbrev, uint64_t AbbrCode) {
40   uint64_t Offset = 0;
41   DataExtractor AbbrevData(Abbrev, true, 0);
42   while (AbbrevData.getULEB128(&Offset) != AbbrCode) {
43     // Tag
44     AbbrevData.getULEB128(&Offset);
45     // DW_CHILDREN
46     AbbrevData.getU8(&Offset);
47     // Attributes
48     while (AbbrevData.getULEB128(&Offset) | AbbrevData.getULEB128(&Offset))
49       ;
50   }
51   return Offset;
52 }
53 
54 static Expected<const char *>
55 getIndexedString(dwarf::Form Form, DataExtractor InfoData, uint64_t &InfoOffset,
56                  StringRef StrOffsets, StringRef Str, uint16_t Version) {
57   if (Form == dwarf::DW_FORM_string)
58     return InfoData.getCStr(&InfoOffset);
59   uint64_t StrIndex;
60   switch (Form) {
61   case dwarf::DW_FORM_strx1:
62     StrIndex = InfoData.getU8(&InfoOffset);
63     break;
64   case dwarf::DW_FORM_strx2:
65     StrIndex = InfoData.getU16(&InfoOffset);
66     break;
67   case dwarf::DW_FORM_strx3:
68     StrIndex = InfoData.getU24(&InfoOffset);
69     break;
70   case dwarf::DW_FORM_strx4:
71     StrIndex = InfoData.getU32(&InfoOffset);
72     break;
73   case dwarf::DW_FORM_strx:
74   case dwarf::DW_FORM_GNU_str_index:
75     StrIndex = InfoData.getULEB128(&InfoOffset);
76     break;
77   default:
78     return make_error<DWPError>(
79         "string field must be encoded with one of the following: "
80         "DW_FORM_string, DW_FORM_strx, DW_FORM_strx1, DW_FORM_strx2, "
81         "DW_FORM_strx3, DW_FORM_strx4, or DW_FORM_GNU_str_index.");
82   }
83   DataExtractor StrOffsetsData(StrOffsets, true, 0);
84   uint64_t StrOffsetsOffset = 4 * StrIndex;
85   StrOffsetsOffset += debugStrOffsetsHeaderSize(StrOffsetsData, Version);
86 
87   uint64_t StrOffset = StrOffsetsData.getU32(&StrOffsetsOffset);
88   DataExtractor StrData(Str, true, 0);
89   return StrData.getCStr(&StrOffset);
90 }
91 
92 static Expected<CompileUnitIdentifiers>
93 getCUIdentifiers(InfoSectionUnitHeader &Header, StringRef Abbrev,
94                  StringRef Info, StringRef StrOffsets, StringRef Str) {
95   DataExtractor InfoData(Info, true, 0);
96   uint64_t Offset = Header.HeaderSize;
97   if (Header.Version >= 5 && Header.UnitType != dwarf::DW_UT_split_compile)
98     return make_error<DWPError>(
99         std::string("unit type DW_UT_split_compile type not found in "
100                     "debug_info header. Unexpected unit type 0x" +
101                     utostr(Header.UnitType) + " found"));
102 
103   CompileUnitIdentifiers ID;
104 
105   uint32_t AbbrCode = InfoData.getULEB128(&Offset);
106   DataExtractor AbbrevData(Abbrev, true, 0);
107   uint64_t AbbrevOffset = getCUAbbrev(Abbrev, AbbrCode);
108   auto Tag = static_cast<dwarf::Tag>(AbbrevData.getULEB128(&AbbrevOffset));
109   if (Tag != dwarf::DW_TAG_compile_unit)
110     return make_error<DWPError>("top level DIE is not a compile unit");
111   // DW_CHILDREN
112   AbbrevData.getU8(&AbbrevOffset);
113   uint32_t Name;
114   dwarf::Form Form;
115   while ((Name = AbbrevData.getULEB128(&AbbrevOffset)) |
116              (Form = static_cast<dwarf::Form>(
117                   AbbrevData.getULEB128(&AbbrevOffset))) &&
118          (Name != 0 || Form != 0)) {
119     switch (Name) {
120     case dwarf::DW_AT_name: {
121       Expected<const char *> EName = getIndexedString(
122           Form, InfoData, Offset, StrOffsets, Str, Header.Version);
123       if (!EName)
124         return EName.takeError();
125       ID.Name = *EName;
126       break;
127     }
128     case dwarf::DW_AT_GNU_dwo_name:
129     case dwarf::DW_AT_dwo_name: {
130       Expected<const char *> EName = getIndexedString(
131           Form, InfoData, Offset, StrOffsets, Str, Header.Version);
132       if (!EName)
133         return EName.takeError();
134       ID.DWOName = *EName;
135       break;
136     }
137     case dwarf::DW_AT_GNU_dwo_id:
138       Header.Signature = InfoData.getU64(&Offset);
139       break;
140     default:
141       DWARFFormValue::skipValue(
142           Form, InfoData, &Offset,
143           dwarf::FormParams({Header.Version, Header.AddrSize, Header.Format}));
144     }
145   }
146   if (!Header.Signature)
147     return make_error<DWPError>("compile unit missing dwo_id");
148   ID.Signature = *Header.Signature;
149   return ID;
150 }
151 
152 static bool isSupportedSectionKind(DWARFSectionKind Kind) {
153   return Kind != DW_SECT_EXT_unknown;
154 }
155 
156 namespace llvm {
157 // Convert an internal section identifier into the index to use with
158 // UnitIndexEntry::Contributions.
159 unsigned getContributionIndex(DWARFSectionKind Kind, uint32_t IndexVersion) {
160   assert(serializeSectionKind(Kind, IndexVersion) >= DW_SECT_INFO);
161   return serializeSectionKind(Kind, IndexVersion) - DW_SECT_INFO;
162 }
163 } // namespace llvm
164 
165 // Convert a UnitIndexEntry::Contributions index to the corresponding on-disk
166 // value of the section identifier.
167 static unsigned getOnDiskSectionId(unsigned Index) {
168   return Index + DW_SECT_INFO;
169 }
170 
171 static StringRef getSubsection(StringRef Section,
172                                const DWARFUnitIndex::Entry &Entry,
173                                DWARFSectionKind Kind) {
174   const auto *Off = Entry.getContribution(Kind);
175   if (!Off)
176     return StringRef();
177   return Section.substr(Off->Offset, Off->Length);
178 }
179 
180 static void
181 addAllTypesFromDWP(MCStreamer &Out,
182                    MapVector<uint64_t, UnitIndexEntry> &TypeIndexEntries,
183                    const DWARFUnitIndex &TUIndex, MCSection *OutputTypes,
184                    StringRef Types, const UnitIndexEntry &TUEntry,
185                    uint32_t &TypesOffset, unsigned TypesContributionIndex) {
186   Out.switchSection(OutputTypes);
187   for (const DWARFUnitIndex::Entry &E : TUIndex.getRows()) {
188     auto *I = E.getContributions();
189     if (!I)
190       continue;
191     auto P = TypeIndexEntries.insert(std::make_pair(E.getSignature(), TUEntry));
192     if (!P.second)
193       continue;
194     auto &Entry = P.first->second;
195     // Zero out the debug_info contribution
196     Entry.Contributions[0] = {};
197     for (auto Kind : TUIndex.getColumnKinds()) {
198       if (!isSupportedSectionKind(Kind))
199         continue;
200       auto &C =
201           Entry.Contributions[getContributionIndex(Kind, TUIndex.getVersion())];
202       C.Offset += I->Offset;
203       C.Length = I->Length;
204       ++I;
205     }
206     auto &C = Entry.Contributions[TypesContributionIndex];
207     Out.emitBytes(Types.substr(
208         C.Offset - TUEntry.Contributions[TypesContributionIndex].Offset,
209         C.Length));
210     C.Offset = TypesOffset;
211     TypesOffset += C.Length;
212   }
213 }
214 
215 static void addAllTypesFromTypesSection(
216     MCStreamer &Out, MapVector<uint64_t, UnitIndexEntry> &TypeIndexEntries,
217     MCSection *OutputTypes, const std::vector<StringRef> &TypesSections,
218     const UnitIndexEntry &CUEntry, uint32_t &TypesOffset) {
219   for (StringRef Types : TypesSections) {
220     Out.switchSection(OutputTypes);
221     uint64_t Offset = 0;
222     DataExtractor Data(Types, true, 0);
223     while (Data.isValidOffset(Offset)) {
224       UnitIndexEntry Entry = CUEntry;
225       // Zero out the debug_info contribution
226       Entry.Contributions[0] = {};
227       auto &C = Entry.Contributions[getContributionIndex(DW_SECT_EXT_TYPES, 2)];
228       C.Offset = TypesOffset;
229       auto PrevOffset = Offset;
230       // Length of the unit, including the 4 byte length field.
231       C.Length = Data.getU32(&Offset) + 4;
232 
233       Data.getU16(&Offset); // Version
234       Data.getU32(&Offset); // Abbrev offset
235       Data.getU8(&Offset);  // Address size
236       auto Signature = Data.getU64(&Offset);
237       Offset = PrevOffset + C.Length;
238 
239       auto P = TypeIndexEntries.insert(std::make_pair(Signature, Entry));
240       if (!P.second)
241         continue;
242 
243       Out.emitBytes(Types.substr(PrevOffset, C.Length));
244       TypesOffset += C.Length;
245     }
246   }
247 }
248 
249 static std::string buildDWODescription(StringRef Name, StringRef DWPName,
250                                        StringRef DWOName) {
251   std::string Text = "\'";
252   Text += Name;
253   Text += '\'';
254   if (!DWPName.empty()) {
255     Text += " (from ";
256     if (!DWOName.empty()) {
257       Text += '\'';
258       Text += DWOName;
259       Text += "' in ";
260     }
261     Text += '\'';
262     Text += DWPName;
263     Text += "')";
264   }
265   return Text;
266 }
267 
268 static Error createError(StringRef Name, Error E) {
269   return make_error<DWPError>(
270       ("failure while decompressing compressed section: '" + Name + "', " +
271        llvm::toString(std::move(E)))
272           .str());
273 }
274 
275 static Error
276 handleCompressedSection(std::deque<SmallString<32>> &UncompressedSections,
277                         SectionRef Sec, StringRef Name, StringRef &Contents) {
278   auto *Obj = dyn_cast<ELFObjectFileBase>(Sec.getObject());
279   if (!Obj ||
280       !(static_cast<ELFSectionRef>(Sec).getFlags() & ELF::SHF_COMPRESSED))
281     return Error::success();
282   bool IsLE = isa<object::ELF32LEObjectFile>(Obj) ||
283               isa<object::ELF64LEObjectFile>(Obj);
284   bool Is64 = isa<object::ELF64LEObjectFile>(Obj) ||
285               isa<object::ELF64BEObjectFile>(Obj);
286   Expected<Decompressor> Dec = Decompressor::create(Name, Contents, IsLE, Is64);
287   if (!Dec)
288     return createError(Name, Dec.takeError());
289 
290   UncompressedSections.emplace_back();
291   if (Error E = Dec->resizeAndDecompress(UncompressedSections.back()))
292     return createError(Name, std::move(E));
293 
294   Contents = UncompressedSections.back();
295   return Error::success();
296 }
297 
298 namespace llvm {
299 // Parse and return the header of an info section compile/type unit.
300 Expected<InfoSectionUnitHeader> parseInfoSectionUnitHeader(StringRef Info) {
301   InfoSectionUnitHeader Header;
302   Error Err = Error::success();
303   uint64_t Offset = 0;
304   DWARFDataExtractor InfoData(Info, true, 0);
305   std::tie(Header.Length, Header.Format) =
306       InfoData.getInitialLength(&Offset, &Err);
307   if (Err)
308     return make_error<DWPError>("cannot parse compile unit length: " +
309                                 llvm::toString(std::move(Err)));
310 
311   if (!InfoData.isValidOffset(Offset + (Header.Length - 1))) {
312     return make_error<DWPError>(
313         "compile unit exceeds .debug_info section range: " +
314         utostr(Offset + Header.Length) + " >= " + utostr(InfoData.size()));
315   }
316 
317   Header.Version = InfoData.getU16(&Offset, &Err);
318   if (Err)
319     return make_error<DWPError>("cannot parse compile unit version: " +
320                                 llvm::toString(std::move(Err)));
321 
322   uint64_t MinHeaderLength;
323   if (Header.Version >= 5) {
324     // Size: Version (2), UnitType (1), AddrSize (1), DebugAbbrevOffset (4),
325     // Signature (8)
326     MinHeaderLength = 16;
327   } else {
328     // Size: Version (2), DebugAbbrevOffset (4), AddrSize (1)
329     MinHeaderLength = 7;
330   }
331   if (Header.Length < MinHeaderLength) {
332     return make_error<DWPError>("unit length is too small: expected at least " +
333                                 utostr(MinHeaderLength) + " got " +
334                                 utostr(Header.Length) + ".");
335   }
336   if (Header.Version >= 5) {
337     Header.UnitType = InfoData.getU8(&Offset);
338     Header.AddrSize = InfoData.getU8(&Offset);
339     Header.DebugAbbrevOffset = InfoData.getU32(&Offset);
340     Header.Signature = InfoData.getU64(&Offset);
341     if (Header.UnitType == dwarf::DW_UT_split_type) {
342       // Type offset.
343       MinHeaderLength += 4;
344       if (Header.Length < MinHeaderLength)
345         return make_error<DWPError>("type unit is missing type offset");
346       InfoData.getU32(&Offset);
347     }
348   } else {
349     // Note that, address_size and debug_abbrev_offset fields have switched
350     // places between dwarf version 4 and 5.
351     Header.DebugAbbrevOffset = InfoData.getU32(&Offset);
352     Header.AddrSize = InfoData.getU8(&Offset);
353   }
354 
355   Header.HeaderSize = Offset;
356   return Header;
357 }
358 
359 void writeStringsAndOffsets(MCStreamer &Out, DWPStringPool &Strings,
360                             MCSection *StrOffsetSection,
361                             StringRef CurStrSection,
362                             StringRef CurStrOffsetSection, uint16_t Version) {
363   // Could possibly produce an error or warning if one of these was non-null but
364   // the other was null.
365   if (CurStrSection.empty() || CurStrOffsetSection.empty())
366     return;
367 
368   DenseMap<uint64_t, uint32_t> OffsetRemapping;
369 
370   DataExtractor Data(CurStrSection, true, 0);
371   uint64_t LocalOffset = 0;
372   uint64_t PrevOffset = 0;
373   while (const char *S = Data.getCStr(&LocalOffset)) {
374     OffsetRemapping[PrevOffset] =
375         Strings.getOffset(S, LocalOffset - PrevOffset);
376     PrevOffset = LocalOffset;
377   }
378 
379   Data = DataExtractor(CurStrOffsetSection, true, 0);
380 
381   Out.switchSection(StrOffsetSection);
382 
383   uint64_t HeaderSize = debugStrOffsetsHeaderSize(Data, Version);
384   uint64_t Offset = 0;
385   uint64_t Size = CurStrOffsetSection.size();
386   // FIXME: This can be caused by bad input and should be handled as such.
387   assert(HeaderSize <= Size && "StrOffsetSection size is less than its header");
388   // Copy the header to the output.
389   Out.emitBytes(Data.getBytes(&Offset, HeaderSize));
390   while (Offset < Size) {
391     auto OldOffset = Data.getU32(&Offset);
392     auto NewOffset = OffsetRemapping[OldOffset];
393     Out.emitIntValue(NewOffset, 4);
394   }
395 }
396 
397 void writeIndexTable(
398     MCStreamer &Out, ArrayRef<unsigned> ContributionOffsets,
399     const MapVector<uint64_t, UnitIndexEntry> &IndexEntries,
400     uint32_t DWARFUnitIndex::Entry::SectionContribution::*Field) {
401   for (const auto &E : IndexEntries)
402     for (size_t I = 0; I != array_lengthof(E.second.Contributions); ++I)
403       if (ContributionOffsets[I])
404         Out.emitIntValue(E.second.Contributions[I].*Field, 4);
405 }
406 
407 void writeIndex(MCStreamer &Out, MCSection *Section,
408                 ArrayRef<unsigned> ContributionOffsets,
409                 const MapVector<uint64_t, UnitIndexEntry> &IndexEntries,
410                 uint32_t IndexVersion) {
411   if (IndexEntries.empty())
412     return;
413 
414   unsigned Columns = 0;
415   for (auto &C : ContributionOffsets)
416     if (C)
417       ++Columns;
418 
419   std::vector<unsigned> Buckets(NextPowerOf2(3 * IndexEntries.size() / 2));
420   uint64_t Mask = Buckets.size() - 1;
421   size_t I = 0;
422   for (const auto &P : IndexEntries) {
423     auto S = P.first;
424     auto H = S & Mask;
425     auto HP = ((S >> 32) & Mask) | 1;
426     while (Buckets[H]) {
427       assert(S != IndexEntries.begin()[Buckets[H] - 1].first &&
428              "Duplicate unit");
429       H = (H + HP) & Mask;
430     }
431     Buckets[H] = I + 1;
432     ++I;
433   }
434 
435   Out.switchSection(Section);
436   Out.emitIntValue(IndexVersion, 4);        // Version
437   Out.emitIntValue(Columns, 4);             // Columns
438   Out.emitIntValue(IndexEntries.size(), 4); // Num Units
439   Out.emitIntValue(Buckets.size(), 4);      // Num Buckets
440 
441   // Write the signatures.
442   for (const auto &I : Buckets)
443     Out.emitIntValue(I ? IndexEntries.begin()[I - 1].first : 0, 8);
444 
445   // Write the indexes.
446   for (const auto &I : Buckets)
447     Out.emitIntValue(I, 4);
448 
449   // Write the column headers (which sections will appear in the table)
450   for (size_t I = 0; I != ContributionOffsets.size(); ++I)
451     if (ContributionOffsets[I])
452       Out.emitIntValue(getOnDiskSectionId(I), 4);
453 
454   // Write the offsets.
455   writeIndexTable(Out, ContributionOffsets, IndexEntries,
456                   &DWARFUnitIndex::Entry::SectionContribution::Offset);
457 
458   // Write the lengths.
459   writeIndexTable(Out, ContributionOffsets, IndexEntries,
460                   &DWARFUnitIndex::Entry::SectionContribution::Length);
461 }
462 
463 Error buildDuplicateError(const std::pair<uint64_t, UnitIndexEntry> &PrevE,
464                           const CompileUnitIdentifiers &ID, StringRef DWPName) {
465   return make_error<DWPError>(
466       std::string("duplicate DWO ID (") + utohexstr(PrevE.first) + ") in " +
467       buildDWODescription(PrevE.second.Name, PrevE.second.DWPName,
468                           PrevE.second.DWOName) +
469       " and " + buildDWODescription(ID.Name, DWPName, ID.DWOName));
470 }
471 
472 Error handleSection(
473     const StringMap<std::pair<MCSection *, DWARFSectionKind>> &KnownSections,
474     const MCSection *StrSection, const MCSection *StrOffsetSection,
475     const MCSection *TypesSection, const MCSection *CUIndexSection,
476     const MCSection *TUIndexSection, const MCSection *InfoSection,
477     const SectionRef &Section, MCStreamer &Out,
478     std::deque<SmallString<32>> &UncompressedSections,
479     uint32_t (&ContributionOffsets)[8], UnitIndexEntry &CurEntry,
480     StringRef &CurStrSection, StringRef &CurStrOffsetSection,
481     std::vector<StringRef> &CurTypesSection,
482     std::vector<StringRef> &CurInfoSection, StringRef &AbbrevSection,
483     StringRef &CurCUIndexSection, StringRef &CurTUIndexSection,
484     std::vector<std::pair<DWARFSectionKind, uint32_t>> &SectionLength) {
485   if (Section.isBSS())
486     return Error::success();
487 
488   if (Section.isVirtual())
489     return Error::success();
490 
491   Expected<StringRef> NameOrErr = Section.getName();
492   if (!NameOrErr)
493     return NameOrErr.takeError();
494   StringRef Name = *NameOrErr;
495 
496   Expected<StringRef> ContentsOrErr = Section.getContents();
497   if (!ContentsOrErr)
498     return ContentsOrErr.takeError();
499   StringRef Contents = *ContentsOrErr;
500 
501   if (auto Err = handleCompressedSection(UncompressedSections, Section, Name,
502                                          Contents))
503     return Err;
504 
505   Name = Name.substr(Name.find_first_not_of("._"));
506 
507   auto SectionPair = KnownSections.find(Name);
508   if (SectionPair == KnownSections.end())
509     return Error::success();
510 
511   if (DWARFSectionKind Kind = SectionPair->second.second) {
512     if (Kind != DW_SECT_EXT_TYPES && Kind != DW_SECT_INFO) {
513       SectionLength.push_back(std::make_pair(Kind, Contents.size()));
514     }
515 
516     if (Kind == DW_SECT_ABBREV) {
517       AbbrevSection = Contents;
518     }
519   }
520 
521   MCSection *OutSection = SectionPair->second.first;
522   if (OutSection == StrOffsetSection)
523     CurStrOffsetSection = Contents;
524   else if (OutSection == StrSection)
525     CurStrSection = Contents;
526   else if (OutSection == TypesSection)
527     CurTypesSection.push_back(Contents);
528   else if (OutSection == CUIndexSection)
529     CurCUIndexSection = Contents;
530   else if (OutSection == TUIndexSection)
531     CurTUIndexSection = Contents;
532   else if (OutSection == InfoSection)
533     CurInfoSection.push_back(Contents);
534   else {
535     Out.switchSection(OutSection);
536     Out.emitBytes(Contents);
537   }
538   return Error::success();
539 }
540 
541 Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
542   const auto &MCOFI = *Out.getContext().getObjectFileInfo();
543   MCSection *const StrSection = MCOFI.getDwarfStrDWOSection();
544   MCSection *const StrOffsetSection = MCOFI.getDwarfStrOffDWOSection();
545   MCSection *const TypesSection = MCOFI.getDwarfTypesDWOSection();
546   MCSection *const CUIndexSection = MCOFI.getDwarfCUIndexSection();
547   MCSection *const TUIndexSection = MCOFI.getDwarfTUIndexSection();
548   MCSection *const InfoSection = MCOFI.getDwarfInfoDWOSection();
549   const StringMap<std::pair<MCSection *, DWARFSectionKind>> KnownSections = {
550       {"debug_info.dwo", {InfoSection, DW_SECT_INFO}},
551       {"debug_types.dwo", {MCOFI.getDwarfTypesDWOSection(), DW_SECT_EXT_TYPES}},
552       {"debug_str_offsets.dwo", {StrOffsetSection, DW_SECT_STR_OFFSETS}},
553       {"debug_str.dwo", {StrSection, static_cast<DWARFSectionKind>(0)}},
554       {"debug_loc.dwo", {MCOFI.getDwarfLocDWOSection(), DW_SECT_EXT_LOC}},
555       {"debug_line.dwo", {MCOFI.getDwarfLineDWOSection(), DW_SECT_LINE}},
556       {"debug_macro.dwo", {MCOFI.getDwarfMacroDWOSection(), DW_SECT_MACRO}},
557       {"debug_abbrev.dwo", {MCOFI.getDwarfAbbrevDWOSection(), DW_SECT_ABBREV}},
558       {"debug_loclists.dwo",
559        {MCOFI.getDwarfLoclistsDWOSection(), DW_SECT_LOCLISTS}},
560       {"debug_rnglists.dwo",
561        {MCOFI.getDwarfRnglistsDWOSection(), DW_SECT_RNGLISTS}},
562       {"debug_cu_index", {CUIndexSection, static_cast<DWARFSectionKind>(0)}},
563       {"debug_tu_index", {TUIndexSection, static_cast<DWARFSectionKind>(0)}}};
564 
565   MapVector<uint64_t, UnitIndexEntry> IndexEntries;
566   MapVector<uint64_t, UnitIndexEntry> TypeIndexEntries;
567 
568   uint32_t ContributionOffsets[8] = {};
569   uint16_t Version = 0;
570   uint32_t IndexVersion = 0;
571 
572   DWPStringPool Strings(Out, StrSection);
573 
574   SmallVector<OwningBinary<object::ObjectFile>, 128> Objects;
575   Objects.reserve(Inputs.size());
576 
577   std::deque<SmallString<32>> UncompressedSections;
578 
579   for (const auto &Input : Inputs) {
580     auto ErrOrObj = object::ObjectFile::createObjectFile(Input);
581     if (!ErrOrObj)
582       return ErrOrObj.takeError();
583 
584     auto &Obj = *ErrOrObj->getBinary();
585     Objects.push_back(std::move(*ErrOrObj));
586 
587     UnitIndexEntry CurEntry = {};
588 
589     StringRef CurStrSection;
590     StringRef CurStrOffsetSection;
591     std::vector<StringRef> CurTypesSection;
592     std::vector<StringRef> CurInfoSection;
593     StringRef AbbrevSection;
594     StringRef CurCUIndexSection;
595     StringRef CurTUIndexSection;
596 
597     // This maps each section contained in this file to its length.
598     // This information is later on used to calculate the contributions,
599     // i.e. offset and length, of each compile/type unit to a section.
600     std::vector<std::pair<DWARFSectionKind, uint32_t>> SectionLength;
601 
602     for (const auto &Section : Obj.sections())
603       if (auto Err = handleSection(
604               KnownSections, StrSection, StrOffsetSection, TypesSection,
605               CUIndexSection, TUIndexSection, InfoSection, Section, Out,
606               UncompressedSections, ContributionOffsets, CurEntry,
607               CurStrSection, CurStrOffsetSection, CurTypesSection,
608               CurInfoSection, AbbrevSection, CurCUIndexSection,
609               CurTUIndexSection, SectionLength))
610         return Err;
611 
612     if (CurInfoSection.empty())
613       continue;
614 
615     Expected<InfoSectionUnitHeader> HeaderOrErr =
616         parseInfoSectionUnitHeader(CurInfoSection.front());
617     if (!HeaderOrErr)
618       return HeaderOrErr.takeError();
619     InfoSectionUnitHeader &Header = *HeaderOrErr;
620 
621     if (Version == 0) {
622       Version = Header.Version;
623       IndexVersion = Version < 5 ? 2 : 5;
624     } else if (Version != Header.Version) {
625       return make_error<DWPError>("incompatible DWARF compile unit versions.");
626     }
627 
628     writeStringsAndOffsets(Out, Strings, StrOffsetSection, CurStrSection,
629                            CurStrOffsetSection, Header.Version);
630 
631     for (auto Pair : SectionLength) {
632       auto Index = getContributionIndex(Pair.first, IndexVersion);
633       CurEntry.Contributions[Index].Offset = ContributionOffsets[Index];
634       ContributionOffsets[Index] +=
635           (CurEntry.Contributions[Index].Length = Pair.second);
636     }
637 
638     uint32_t &InfoSectionOffset =
639         ContributionOffsets[getContributionIndex(DW_SECT_INFO, IndexVersion)];
640     if (CurCUIndexSection.empty()) {
641       bool FoundCUUnit = false;
642       Out.switchSection(InfoSection);
643       for (StringRef Info : CurInfoSection) {
644         uint64_t UnitOffset = 0;
645         while (Info.size() > UnitOffset) {
646           Expected<InfoSectionUnitHeader> HeaderOrError =
647               parseInfoSectionUnitHeader(Info.substr(UnitOffset, Info.size()));
648           if (!HeaderOrError)
649             return HeaderOrError.takeError();
650           InfoSectionUnitHeader &Header = *HeaderOrError;
651 
652           UnitIndexEntry Entry = CurEntry;
653           auto &C = Entry.Contributions[getContributionIndex(DW_SECT_INFO,
654                                                              IndexVersion)];
655           C.Offset = InfoSectionOffset;
656           C.Length = Header.Length + 4;
657           UnitOffset += C.Length;
658           if (Header.Version < 5 ||
659               Header.UnitType == dwarf::DW_UT_split_compile) {
660             Expected<CompileUnitIdentifiers> EID =
661                 getCUIdentifiers(Header, AbbrevSection,
662                                  Info.substr(UnitOffset - C.Length, C.Length),
663                                  CurStrOffsetSection, CurStrSection);
664 
665             if (!EID)
666               return createFileError(Input, EID.takeError());
667             const auto &ID = *EID;
668             auto P = IndexEntries.insert(std::make_pair(ID.Signature, Entry));
669             if (!P.second)
670               return buildDuplicateError(*P.first, ID, "");
671             P.first->second.Name = ID.Name;
672             P.first->second.DWOName = ID.DWOName;
673 
674             FoundCUUnit = true;
675           } else if (Header.UnitType == dwarf::DW_UT_split_type) {
676             auto P = TypeIndexEntries.insert(
677                 std::make_pair(*Header.Signature, Entry));
678             if (!P.second)
679               continue;
680           }
681           Out.emitBytes(Info.substr(UnitOffset - C.Length, C.Length));
682           InfoSectionOffset += C.Length;
683         }
684       }
685 
686       if (!FoundCUUnit)
687         return make_error<DWPError>("no compile unit found in file: " + Input);
688 
689       if (IndexVersion == 2) {
690         // Add types from the .debug_types section from DWARF < 5.
691         addAllTypesFromTypesSection(
692             Out, TypeIndexEntries, TypesSection, CurTypesSection, CurEntry,
693             ContributionOffsets[getContributionIndex(DW_SECT_EXT_TYPES, 2)]);
694       }
695       continue;
696     }
697 
698     if (CurInfoSection.size() != 1)
699       return make_error<DWPError>("expected exactly one occurrence of a debug "
700                                   "info section in a .dwp file");
701     StringRef DwpSingleInfoSection = CurInfoSection.front();
702 
703     DWARFUnitIndex CUIndex(DW_SECT_INFO);
704     DataExtractor CUIndexData(CurCUIndexSection, Obj.isLittleEndian(), 0);
705     if (!CUIndex.parse(CUIndexData))
706       return make_error<DWPError>("failed to parse cu_index");
707     if (CUIndex.getVersion() != IndexVersion)
708       return make_error<DWPError>("incompatible cu_index versions, found " +
709                                   utostr(CUIndex.getVersion()) +
710                                   " and expecting " + utostr(IndexVersion));
711 
712     Out.switchSection(InfoSection);
713     for (const DWARFUnitIndex::Entry &E : CUIndex.getRows()) {
714       auto *I = E.getContributions();
715       if (!I)
716         continue;
717       auto P = IndexEntries.insert(std::make_pair(E.getSignature(), CurEntry));
718       StringRef CUInfoSection =
719           getSubsection(DwpSingleInfoSection, E, DW_SECT_INFO);
720       Expected<InfoSectionUnitHeader> HeaderOrError =
721           parseInfoSectionUnitHeader(CUInfoSection);
722       if (!HeaderOrError)
723         return HeaderOrError.takeError();
724       InfoSectionUnitHeader &Header = *HeaderOrError;
725 
726       Expected<CompileUnitIdentifiers> EID = getCUIdentifiers(
727           Header, getSubsection(AbbrevSection, E, DW_SECT_ABBREV),
728           CUInfoSection,
729           getSubsection(CurStrOffsetSection, E, DW_SECT_STR_OFFSETS),
730           CurStrSection);
731       if (!EID)
732         return createFileError(Input, EID.takeError());
733       const auto &ID = *EID;
734       if (!P.second)
735         return buildDuplicateError(*P.first, ID, Input);
736       auto &NewEntry = P.first->second;
737       NewEntry.Name = ID.Name;
738       NewEntry.DWOName = ID.DWOName;
739       NewEntry.DWPName = Input;
740       for (auto Kind : CUIndex.getColumnKinds()) {
741         if (!isSupportedSectionKind(Kind))
742           continue;
743         auto &C =
744             NewEntry.Contributions[getContributionIndex(Kind, IndexVersion)];
745         C.Offset += I->Offset;
746         C.Length = I->Length;
747         ++I;
748       }
749       unsigned Index = getContributionIndex(DW_SECT_INFO, IndexVersion);
750       auto &C = NewEntry.Contributions[Index];
751       Out.emitBytes(CUInfoSection);
752       C.Offset = InfoSectionOffset;
753       InfoSectionOffset += C.Length;
754     }
755 
756     if (!CurTUIndexSection.empty()) {
757       llvm::DWARFSectionKind TUSectionKind;
758       MCSection *OutSection;
759       StringRef TypeInputSection;
760       // Write type units into debug info section for DWARFv5.
761       if (Version >= 5) {
762         TUSectionKind = DW_SECT_INFO;
763         OutSection = InfoSection;
764         TypeInputSection = DwpSingleInfoSection;
765       } else {
766         // Write type units into debug types section for DWARF < 5.
767         if (CurTypesSection.size() != 1)
768           return make_error<DWPError>(
769               "multiple type unit sections in .dwp file");
770 
771         TUSectionKind = DW_SECT_EXT_TYPES;
772         OutSection = TypesSection;
773         TypeInputSection = CurTypesSection.front();
774       }
775 
776       DWARFUnitIndex TUIndex(TUSectionKind);
777       DataExtractor TUIndexData(CurTUIndexSection, Obj.isLittleEndian(), 0);
778       if (!TUIndex.parse(TUIndexData))
779         return make_error<DWPError>("failed to parse tu_index");
780       if (TUIndex.getVersion() != IndexVersion)
781         return make_error<DWPError>("incompatible tu_index versions, found " +
782                                     utostr(TUIndex.getVersion()) +
783                                     " and expecting " + utostr(IndexVersion));
784 
785       unsigned TypesContributionIndex =
786           getContributionIndex(TUSectionKind, IndexVersion);
787       addAllTypesFromDWP(Out, TypeIndexEntries, TUIndex, OutSection,
788                          TypeInputSection, CurEntry,
789                          ContributionOffsets[TypesContributionIndex],
790                          TypesContributionIndex);
791     }
792   }
793 
794   if (Version < 5) {
795     // Lie about there being no info contributions so the TU index only includes
796     // the type unit contribution for DWARF < 5. In DWARFv5 the TU index has a
797     // contribution to the info section, so we do not want to lie about it.
798     ContributionOffsets[0] = 0;
799   }
800   writeIndex(Out, MCOFI.getDwarfTUIndexSection(), ContributionOffsets,
801              TypeIndexEntries, IndexVersion);
802 
803   if (Version < 5) {
804     // Lie about the type contribution for DWARF < 5. In DWARFv5 the type
805     // section does not exist, so no need to do anything about this.
806     ContributionOffsets[getContributionIndex(DW_SECT_EXT_TYPES, 2)] = 0;
807     // Unlie about the info contribution
808     ContributionOffsets[0] = 1;
809   }
810 
811   writeIndex(Out, MCOFI.getDwarfCUIndexSection(), ContributionOffsets,
812              IndexEntries, IndexVersion);
813 
814   return Error::success();
815 }
816 } // namespace llvm
817