1 //===-- llvm-dwp.cpp - Split DWARF merging tool for llvm ------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // A utility for merging DWARF 5 Split DWARF .dwo files into .dwp (DWARF
11 // package files).
12 //
13 //===----------------------------------------------------------------------===//
14 #include "DWPError.h"
15 #include "DWPStringPool.h"
16 #include "llvm/ADT/MapVector.h"
17 #include "llvm/ADT/STLExtras.h"
18 #include "llvm/ADT/StringSet.h"
19 #include "llvm/CodeGen/AsmPrinter.h"
20 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
21 #include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
22 #include "llvm/MC/MCAsmInfo.h"
23 #include "llvm/MC/MCContext.h"
24 #include "llvm/MC/MCInstrInfo.h"
25 #include "llvm/MC/MCObjectFileInfo.h"
26 #include "llvm/MC/MCRegisterInfo.h"
27 #include "llvm/MC/MCSectionELF.h"
28 #include "llvm/MC/MCStreamer.h"
29 #include "llvm/MC/MCTargetOptionsCommandFlags.h"
30 #include "llvm/Object/ObjectFile.h"
31 #include "llvm/Support/Compression.h"
32 #include "llvm/Support/DataExtractor.h"
33 #include "llvm/Support/Error.h"
34 #include "llvm/Support/FileSystem.h"
35 #include "llvm/Support/MathExtras.h"
36 #include "llvm/Support/MemoryBuffer.h"
37 #include "llvm/Support/Options.h"
38 #include "llvm/Support/TargetRegistry.h"
39 #include "llvm/Support/TargetSelect.h"
40 #include "llvm/Support/raw_ostream.h"
41 #include "llvm/Target/TargetMachine.h"
42 #include <deque>
43 #include <iostream>
44 #include <memory>
45 
46 using namespace llvm;
47 using namespace llvm::object;
48 using namespace cl;
49 
50 OptionCategory DwpCategory("Specific Options");
51 static list<std::string> InputFiles(Positional, OneOrMore,
52                                     desc("<input files>"), cat(DwpCategory));
53 
54 static opt<std::string> OutputFilename(Required, "o",
55                                        desc("Specify the output file."),
56                                        value_desc("filename"),
57                                        cat(DwpCategory));
58 
writeStringsAndOffsets(MCStreamer & Out,DWPStringPool & Strings,MCSection * StrOffsetSection,StringRef CurStrSection,StringRef CurStrOffsetSection)59 static void writeStringsAndOffsets(MCStreamer &Out, DWPStringPool &Strings,
60                                    MCSection *StrOffsetSection,
61                                    StringRef CurStrSection,
62                                    StringRef CurStrOffsetSection) {
63   // Could possibly produce an error or warning if one of these was non-null but
64   // the other was null.
65   if (CurStrSection.empty() || CurStrOffsetSection.empty())
66     return;
67 
68   DenseMap<uint32_t, uint32_t> OffsetRemapping;
69 
70   DataExtractor Data(CurStrSection, true, 0);
71   uint32_t LocalOffset = 0;
72   uint32_t PrevOffset = 0;
73   while (const char *s = Data.getCStr(&LocalOffset)) {
74     OffsetRemapping[PrevOffset] =
75         Strings.getOffset(s, LocalOffset - PrevOffset);
76     PrevOffset = LocalOffset;
77   }
78 
79   Data = DataExtractor(CurStrOffsetSection, true, 0);
80 
81   Out.SwitchSection(StrOffsetSection);
82 
83   uint32_t Offset = 0;
84   uint64_t Size = CurStrOffsetSection.size();
85   while (Offset < Size) {
86     auto OldOffset = Data.getU32(&Offset);
87     auto NewOffset = OffsetRemapping[OldOffset];
88     Out.EmitIntValue(NewOffset, 4);
89   }
90 }
91 
getCUAbbrev(StringRef Abbrev,uint64_t AbbrCode)92 static uint32_t getCUAbbrev(StringRef Abbrev, uint64_t AbbrCode) {
93   uint64_t CurCode;
94   uint32_t Offset = 0;
95   DataExtractor AbbrevData(Abbrev, true, 0);
96   while ((CurCode = AbbrevData.getULEB128(&Offset)) != AbbrCode) {
97     // Tag
98     AbbrevData.getULEB128(&Offset);
99     // DW_CHILDREN
100     AbbrevData.getU8(&Offset);
101     // Attributes
102     while (AbbrevData.getULEB128(&Offset) | AbbrevData.getULEB128(&Offset))
103       ;
104   }
105   return Offset;
106 }
107 
108 struct CompileUnitIdentifiers {
109   uint64_t Signature = 0;
110   const char *Name = "";
111   const char *DWOName = "";
112 };
113 
114 static Expected<const char *>
getIndexedString(uint32_t Form,DataExtractor InfoData,uint32_t & InfoOffset,StringRef StrOffsets,StringRef Str)115 getIndexedString(uint32_t Form, DataExtractor InfoData, uint32_t &InfoOffset,
116                  StringRef StrOffsets, StringRef Str) {
117   if (Form == dwarf::DW_FORM_string)
118     return InfoData.getCStr(&InfoOffset);
119   if (Form != dwarf::DW_FORM_GNU_str_index)
120     return make_error<DWPError>(
121         "string field encoded without DW_FORM_string or DW_FORM_GNU_str_index");
122   auto StrIndex = InfoData.getULEB128(&InfoOffset);
123   DataExtractor StrOffsetsData(StrOffsets, true, 0);
124   uint32_t StrOffsetsOffset = 4 * StrIndex;
125   uint32_t StrOffset = StrOffsetsData.getU32(&StrOffsetsOffset);
126   DataExtractor StrData(Str, true, 0);
127   return StrData.getCStr(&StrOffset);
128 }
129 
getCUIdentifiers(StringRef Abbrev,StringRef Info,StringRef StrOffsets,StringRef Str)130 static Expected<CompileUnitIdentifiers> getCUIdentifiers(StringRef Abbrev,
131                                                          StringRef Info,
132                                                          StringRef StrOffsets,
133                                                          StringRef Str) {
134   uint32_t Offset = 0;
135   DataExtractor InfoData(Info, true, 0);
136   InfoData.getU32(&Offset); // Length
137   uint16_t Version = InfoData.getU16(&Offset);
138   InfoData.getU32(&Offset); // Abbrev offset (should be zero)
139   uint8_t AddrSize = InfoData.getU8(&Offset);
140 
141   uint32_t AbbrCode = InfoData.getULEB128(&Offset);
142 
143   DataExtractor AbbrevData(Abbrev, true, 0);
144   uint32_t AbbrevOffset = getCUAbbrev(Abbrev, AbbrCode);
145   uint64_t Tag = AbbrevData.getULEB128(&AbbrevOffset);
146   if (Tag != dwarf::DW_TAG_compile_unit)
147     return make_error<DWPError>("top level DIE is not a compile unit");
148   // DW_CHILDREN
149   AbbrevData.getU8(&AbbrevOffset);
150   uint32_t Name;
151   uint32_t Form;
152   CompileUnitIdentifiers ID;
153   while ((Name = AbbrevData.getULEB128(&AbbrevOffset)) |
154              (Form = AbbrevData.getULEB128(&AbbrevOffset)) &&
155          (Name != 0 || Form != 0)) {
156     switch (Name) {
157     case dwarf::DW_AT_name: {
158       Expected<const char *> EName =
159           getIndexedString(Form, InfoData, Offset, StrOffsets, Str);
160       if (!EName)
161         return EName.takeError();
162       ID.Name = *EName;
163       break;
164     }
165     case dwarf::DW_AT_GNU_dwo_name: {
166       Expected<const char *> EName =
167           getIndexedString(Form, InfoData, Offset, StrOffsets, Str);
168       if (!EName)
169         return EName.takeError();
170       ID.DWOName = *EName;
171       break;
172     }
173     case dwarf::DW_AT_GNU_dwo_id:
174       ID.Signature = InfoData.getU64(&Offset);
175       break;
176     default:
177       DWARFFormValue::skipValue(Form, InfoData, &Offset, Version, AddrSize);
178     }
179   }
180   return ID;
181 }
182 
183 struct UnitIndexEntry {
184   DWARFUnitIndex::Entry::SectionContribution Contributions[8];
185   std::string Name;
186   std::string DWOName;
187   StringRef DWPName;
188 };
189 
getSubsection(StringRef Section,const DWARFUnitIndex::Entry & Entry,DWARFSectionKind Kind)190 static StringRef getSubsection(StringRef Section,
191                                const DWARFUnitIndex::Entry &Entry,
192                                DWARFSectionKind Kind) {
193   const auto *Off = Entry.getOffset(Kind);
194   if (!Off)
195     return StringRef();
196   return Section.substr(Off->Offset, Off->Length);
197 }
198 
addAllTypesFromDWP(MCStreamer & Out,MapVector<uint64_t,UnitIndexEntry> & TypeIndexEntries,const DWARFUnitIndex & TUIndex,MCSection * OutputTypes,StringRef Types,const UnitIndexEntry & TUEntry,uint32_t & TypesOffset)199 static void addAllTypesFromDWP(
200     MCStreamer &Out, MapVector<uint64_t, UnitIndexEntry> &TypeIndexEntries,
201     const DWARFUnitIndex &TUIndex, MCSection *OutputTypes, StringRef Types,
202     const UnitIndexEntry &TUEntry, uint32_t &TypesOffset) {
203   Out.SwitchSection(OutputTypes);
204   for (const DWARFUnitIndex::Entry &E : TUIndex.getRows()) {
205     auto *I = E.getOffsets();
206     if (!I)
207       continue;
208     auto P = TypeIndexEntries.insert(std::make_pair(E.getSignature(), TUEntry));
209     if (!P.second)
210       continue;
211     auto &Entry = P.first->second;
212     // Zero out the debug_info contribution
213     Entry.Contributions[0] = {};
214     for (auto Kind : TUIndex.getColumnKinds()) {
215       auto &C = Entry.Contributions[Kind - DW_SECT_INFO];
216       C.Offset += I->Offset;
217       C.Length = I->Length;
218       ++I;
219     }
220     auto &C = Entry.Contributions[DW_SECT_TYPES - DW_SECT_INFO];
221     Out.EmitBytes(Types.substr(
222         C.Offset - TUEntry.Contributions[DW_SECT_TYPES - DW_SECT_INFO].Offset,
223         C.Length));
224     C.Offset = TypesOffset;
225     TypesOffset += C.Length;
226   }
227 }
228 
addAllTypes(MCStreamer & Out,MapVector<uint64_t,UnitIndexEntry> & TypeIndexEntries,MCSection * OutputTypes,const std::vector<StringRef> & TypesSections,const UnitIndexEntry & CUEntry,uint32_t & TypesOffset)229 static void addAllTypes(MCStreamer &Out,
230                         MapVector<uint64_t, UnitIndexEntry> &TypeIndexEntries,
231                         MCSection *OutputTypes,
232                         const std::vector<StringRef> &TypesSections,
233                         const UnitIndexEntry &CUEntry, uint32_t &TypesOffset) {
234   for (StringRef Types : TypesSections) {
235     Out.SwitchSection(OutputTypes);
236     uint32_t Offset = 0;
237     DataExtractor Data(Types, true, 0);
238     while (Data.isValidOffset(Offset)) {
239       UnitIndexEntry Entry = CUEntry;
240       // Zero out the debug_info contribution
241       Entry.Contributions[0] = {};
242       auto &C = Entry.Contributions[DW_SECT_TYPES - DW_SECT_INFO];
243       C.Offset = TypesOffset;
244       auto PrevOffset = Offset;
245       // Length of the unit, including the 4 byte length field.
246       C.Length = Data.getU32(&Offset) + 4;
247 
248       Data.getU16(&Offset); // Version
249       Data.getU32(&Offset); // Abbrev offset
250       Data.getU8(&Offset);  // Address size
251       auto Signature = Data.getU64(&Offset);
252       Offset = PrevOffset + C.Length;
253 
254       auto P = TypeIndexEntries.insert(std::make_pair(Signature, Entry));
255       if (!P.second)
256         continue;
257 
258       Out.EmitBytes(Types.substr(PrevOffset, C.Length));
259       TypesOffset += C.Length;
260     }
261   }
262 }
263 
264 static void
writeIndexTable(MCStreamer & Out,ArrayRef<unsigned> ContributionOffsets,const MapVector<uint64_t,UnitIndexEntry> & IndexEntries,uint32_t DWARFUnitIndex::Entry::SectionContribution::* Field)265 writeIndexTable(MCStreamer &Out, ArrayRef<unsigned> ContributionOffsets,
266                 const MapVector<uint64_t, UnitIndexEntry> &IndexEntries,
267                 uint32_t DWARFUnitIndex::Entry::SectionContribution::*Field) {
268   for (const auto &E : IndexEntries)
269     for (size_t i = 0; i != array_lengthof(E.second.Contributions); ++i)
270       if (ContributionOffsets[i])
271         Out.EmitIntValue(E.second.Contributions[i].*Field, 4);
272 }
273 
274 static void
writeIndex(MCStreamer & Out,MCSection * Section,ArrayRef<unsigned> ContributionOffsets,const MapVector<uint64_t,UnitIndexEntry> & IndexEntries)275 writeIndex(MCStreamer &Out, MCSection *Section,
276            ArrayRef<unsigned> ContributionOffsets,
277            const MapVector<uint64_t, UnitIndexEntry> &IndexEntries) {
278   if (IndexEntries.empty())
279     return;
280 
281   unsigned Columns = 0;
282   for (auto &C : ContributionOffsets)
283     if (C)
284       ++Columns;
285 
286   std::vector<unsigned> Buckets(NextPowerOf2(3 * IndexEntries.size() / 2));
287   uint64_t Mask = Buckets.size() - 1;
288   size_t i = 0;
289   for (const auto &P : IndexEntries) {
290     auto S = P.first;
291     auto H = S & Mask;
292     auto HP = ((S >> 32) & Mask) | 1;
293     while (Buckets[H]) {
294       assert(S != IndexEntries.begin()[Buckets[H] - 1].first &&
295              "Duplicate unit");
296       H = (H + HP) & Mask;
297     }
298     Buckets[H] = i + 1;
299     ++i;
300   }
301 
302   Out.SwitchSection(Section);
303   Out.EmitIntValue(2, 4);                   // Version
304   Out.EmitIntValue(Columns, 4);             // Columns
305   Out.EmitIntValue(IndexEntries.size(), 4); // Num Units
306   Out.EmitIntValue(Buckets.size(), 4);      // Num Buckets
307 
308   // Write the signatures.
309   for (const auto &I : Buckets)
310     Out.EmitIntValue(I ? IndexEntries.begin()[I - 1].first : 0, 8);
311 
312   // Write the indexes.
313   for (const auto &I : Buckets)
314     Out.EmitIntValue(I, 4);
315 
316   // Write the column headers (which sections will appear in the table)
317   for (size_t i = 0; i != ContributionOffsets.size(); ++i)
318     if (ContributionOffsets[i])
319       Out.EmitIntValue(i + DW_SECT_INFO, 4);
320 
321   // Write the offsets.
322   writeIndexTable(Out, ContributionOffsets, IndexEntries,
323                   &DWARFUnitIndex::Entry::SectionContribution::Offset);
324 
325   // Write the lengths.
326   writeIndexTable(Out, ContributionOffsets, IndexEntries,
327                   &DWARFUnitIndex::Entry::SectionContribution::Length);
328 }
consumeCompressedDebugSectionHeader(StringRef & data,uint64_t & OriginalSize)329 static bool consumeCompressedDebugSectionHeader(StringRef &data,
330                                                 uint64_t &OriginalSize) {
331   // Consume "ZLIB" prefix.
332   if (!data.startswith("ZLIB"))
333     return false;
334   data = data.substr(4);
335   // Consume uncompressed section size (big-endian 8 bytes).
336   DataExtractor extractor(data, false, 8);
337   uint32_t Offset = 0;
338   OriginalSize = extractor.getU64(&Offset);
339   if (Offset == 0)
340     return false;
341   data = data.substr(Offset);
342   return true;
343 }
344 
buildDWODescription(StringRef Name,StringRef DWPName,StringRef DWOName)345 std::string buildDWODescription(StringRef Name, StringRef DWPName, StringRef DWOName) {
346   std::string Text = "\'";
347   Text += Name;
348   Text += '\'';
349   if (!DWPName.empty()) {
350     Text += " (from ";
351     if (!DWOName.empty()) {
352       Text += '\'';
353       Text += DWOName;
354       Text += "' in ";
355     }
356     Text += '\'';
357     Text += DWPName;
358     Text += "')";
359   }
360   return Text;
361 }
362 
handleCompressedSection(std::deque<SmallString<32>> & UncompressedSections,StringRef & Name,StringRef & Contents)363 static Error handleCompressedSection(
364     std::deque<SmallString<32>> &UncompressedSections, StringRef &Name,
365     StringRef &Contents) {
366   if (!Name.startswith("zdebug_"))
367     return Error();
368   UncompressedSections.emplace_back();
369   uint64_t OriginalSize;
370   if (!zlib::isAvailable())
371     return make_error<DWPError>("zlib not available");
372   if (!consumeCompressedDebugSectionHeader(Contents, OriginalSize) ||
373       zlib::uncompress(Contents, UncompressedSections.back(), OriginalSize) !=
374           zlib::StatusOK)
375     return make_error<DWPError>(
376         ("failure while decompressing compressed section: '" + Name + "\'")
377             .str());
378   Name = Name.substr(1);
379   Contents = UncompressedSections.back();
380   return Error();
381 }
382 
handleSection(const StringMap<std::pair<MCSection *,DWARFSectionKind>> & KnownSections,const MCSection * StrSection,const MCSection * StrOffsetSection,const MCSection * TypesSection,const MCSection * CUIndexSection,const MCSection * TUIndexSection,const SectionRef & Section,MCStreamer & Out,std::deque<SmallString<32>> & UncompressedSections,uint32_t (& ContributionOffsets)[8],UnitIndexEntry & CurEntry,StringRef & CurStrSection,StringRef & CurStrOffsetSection,std::vector<StringRef> & CurTypesSection,StringRef & InfoSection,StringRef & AbbrevSection,StringRef & CurCUIndexSection,StringRef & CurTUIndexSection)383 static Error handleSection(
384     const StringMap<std::pair<MCSection *, DWARFSectionKind>> &KnownSections,
385     const MCSection *StrSection, const MCSection *StrOffsetSection,
386     const MCSection *TypesSection, const MCSection *CUIndexSection,
387     const MCSection *TUIndexSection, const SectionRef &Section, MCStreamer &Out,
388     std::deque<SmallString<32>> &UncompressedSections,
389     uint32_t (&ContributionOffsets)[8], UnitIndexEntry &CurEntry,
390     StringRef &CurStrSection, StringRef &CurStrOffsetSection,
391     std::vector<StringRef> &CurTypesSection, StringRef &InfoSection,
392     StringRef &AbbrevSection, StringRef &CurCUIndexSection,
393     StringRef &CurTUIndexSection) {
394   if (Section.isBSS())
395     return Error();
396 
397   if (Section.isVirtual())
398     return Error();
399 
400   StringRef Name;
401   if (std::error_code Err = Section.getName(Name))
402     return errorCodeToError(Err);
403 
404   Name = Name.substr(Name.find_first_not_of("._"));
405 
406   StringRef Contents;
407   if (auto Err = Section.getContents(Contents))
408     return errorCodeToError(Err);
409 
410   if (auto Err = handleCompressedSection(UncompressedSections, Name, Contents))
411     return Err;
412 
413   auto SectionPair = KnownSections.find(Name);
414   if (SectionPair == KnownSections.end())
415     return Error();
416 
417   if (DWARFSectionKind Kind = SectionPair->second.second) {
418     auto Index = Kind - DW_SECT_INFO;
419     if (Kind != DW_SECT_TYPES) {
420       CurEntry.Contributions[Index].Offset = ContributionOffsets[Index];
421       ContributionOffsets[Index] +=
422           (CurEntry.Contributions[Index].Length = Contents.size());
423     }
424 
425     switch (Kind) {
426     case DW_SECT_INFO:
427       InfoSection = Contents;
428       break;
429     case DW_SECT_ABBREV:
430       AbbrevSection = Contents;
431       break;
432     default:
433       break;
434     }
435   }
436 
437   MCSection *OutSection = SectionPair->second.first;
438   if (OutSection == StrOffsetSection)
439     CurStrOffsetSection = Contents;
440   else if (OutSection == StrSection)
441     CurStrSection = Contents;
442   else if (OutSection == TypesSection)
443     CurTypesSection.push_back(Contents);
444   else if (OutSection == CUIndexSection)
445     CurCUIndexSection = Contents;
446   else if (OutSection == TUIndexSection)
447     CurTUIndexSection = Contents;
448   else {
449     Out.SwitchSection(OutSection);
450     Out.EmitBytes(Contents);
451   }
452   return Error();
453 }
454 
455 static Error
buildDuplicateError(const std::pair<uint64_t,UnitIndexEntry> & PrevE,const CompileUnitIdentifiers & ID,StringRef DWPName)456 buildDuplicateError(const std::pair<uint64_t, UnitIndexEntry> &PrevE,
457                     const CompileUnitIdentifiers &ID, StringRef DWPName) {
458   return make_error<DWPError>(
459       std::string("Duplicate DWO ID (") + utohexstr(PrevE.first) + ") in " +
460       buildDWODescription(PrevE.second.Name, PrevE.second.DWPName,
461                           PrevE.second.DWOName) +
462       " and " + buildDWODescription(ID.Name, DWPName, ID.DWOName));
463 }
464 
write(MCStreamer & Out,ArrayRef<std::string> Inputs)465 static Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
466   const auto &MCOFI = *Out.getContext().getObjectFileInfo();
467   MCSection *const StrSection = MCOFI.getDwarfStrDWOSection();
468   MCSection *const StrOffsetSection = MCOFI.getDwarfStrOffDWOSection();
469   MCSection *const TypesSection = MCOFI.getDwarfTypesDWOSection();
470   MCSection *const CUIndexSection = MCOFI.getDwarfCUIndexSection();
471   MCSection *const TUIndexSection = MCOFI.getDwarfTUIndexSection();
472   const StringMap<std::pair<MCSection *, DWARFSectionKind>> KnownSections = {
473       {"debug_info.dwo", {MCOFI.getDwarfInfoDWOSection(), DW_SECT_INFO}},
474       {"debug_types.dwo", {MCOFI.getDwarfTypesDWOSection(), DW_SECT_TYPES}},
475       {"debug_str_offsets.dwo", {StrOffsetSection, DW_SECT_STR_OFFSETS}},
476       {"debug_str.dwo", {StrSection, static_cast<DWARFSectionKind>(0)}},
477       {"debug_loc.dwo", {MCOFI.getDwarfLocDWOSection(), DW_SECT_LOC}},
478       {"debug_line.dwo", {MCOFI.getDwarfLineDWOSection(), DW_SECT_LINE}},
479       {"debug_abbrev.dwo", {MCOFI.getDwarfAbbrevDWOSection(), DW_SECT_ABBREV}},
480       {"debug_cu_index", {CUIndexSection, static_cast<DWARFSectionKind>(0)}},
481       {"debug_tu_index", {TUIndexSection, static_cast<DWARFSectionKind>(0)}}};
482 
483   MapVector<uint64_t, UnitIndexEntry> IndexEntries;
484   MapVector<uint64_t, UnitIndexEntry> TypeIndexEntries;
485 
486   uint32_t ContributionOffsets[8] = {};
487 
488   DWPStringPool Strings(Out, StrSection);
489 
490   SmallVector<OwningBinary<object::ObjectFile>, 128> Objects;
491   Objects.reserve(Inputs.size());
492 
493   std::deque<SmallString<32>> UncompressedSections;
494 
495   for (const auto &Input : Inputs) {
496     auto ErrOrObj = object::ObjectFile::createObjectFile(Input);
497     if (!ErrOrObj)
498       return ErrOrObj.takeError();
499 
500     auto &Obj = *ErrOrObj->getBinary();
501     Objects.push_back(std::move(*ErrOrObj));
502 
503     UnitIndexEntry CurEntry = {};
504 
505     StringRef CurStrSection;
506     StringRef CurStrOffsetSection;
507     std::vector<StringRef> CurTypesSection;
508     StringRef InfoSection;
509     StringRef AbbrevSection;
510     StringRef CurCUIndexSection;
511     StringRef CurTUIndexSection;
512 
513     for (const auto &Section : Obj.sections())
514       if (auto Err = handleSection(
515               KnownSections, StrSection, StrOffsetSection, TypesSection,
516               CUIndexSection, TUIndexSection, Section, Out,
517               UncompressedSections, ContributionOffsets, CurEntry,
518               CurStrSection, CurStrOffsetSection, CurTypesSection, InfoSection,
519               AbbrevSection, CurCUIndexSection, CurTUIndexSection))
520         return Err;
521 
522     if (InfoSection.empty())
523       continue;
524 
525     writeStringsAndOffsets(Out, Strings, StrOffsetSection, CurStrSection,
526                            CurStrOffsetSection);
527 
528     if (CurCUIndexSection.empty()) {
529       Expected<CompileUnitIdentifiers> EID = getCUIdentifiers(
530           AbbrevSection, InfoSection, CurStrOffsetSection, CurStrSection);
531       if (!EID)
532         return EID.takeError();
533       const auto &ID = *EID;
534       auto P = IndexEntries.insert(std::make_pair(ID.Signature, CurEntry));
535       if (!P.second)
536         return buildDuplicateError(*P.first, ID, "");
537       P.first->second.Name = ID.Name;
538       P.first->second.DWOName = ID.DWOName;
539       addAllTypes(Out, TypeIndexEntries, TypesSection, CurTypesSection,
540                   CurEntry, ContributionOffsets[DW_SECT_TYPES - DW_SECT_INFO]);
541       continue;
542     }
543 
544     DWARFUnitIndex CUIndex(DW_SECT_INFO);
545     DataExtractor CUIndexData(CurCUIndexSection, Obj.isLittleEndian(), 0);
546     if (!CUIndex.parse(CUIndexData))
547       return make_error<DWPError>("Failed to parse cu_index");
548 
549     for (const DWARFUnitIndex::Entry &E : CUIndex.getRows()) {
550       auto *I = E.getOffsets();
551       if (!I)
552         continue;
553       auto P = IndexEntries.insert(std::make_pair(E.getSignature(), CurEntry));
554       Expected<CompileUnitIdentifiers> EID = getCUIdentifiers(
555           getSubsection(AbbrevSection, E, DW_SECT_ABBREV),
556           getSubsection(InfoSection, E, DW_SECT_INFO),
557           getSubsection(CurStrOffsetSection, E, DW_SECT_STR_OFFSETS),
558           CurStrSection);
559       if (!EID)
560         return EID.takeError();
561       const auto &ID = *EID;
562       if (!P.second)
563         return buildDuplicateError(*P.first, ID, Input);
564       auto &NewEntry = P.first->second;
565       NewEntry.Name = ID.Name;
566       NewEntry.DWOName = ID.DWOName;
567       NewEntry.DWPName = Input;
568       for (auto Kind : CUIndex.getColumnKinds()) {
569         auto &C = NewEntry.Contributions[Kind - DW_SECT_INFO];
570         C.Offset += I->Offset;
571         C.Length = I->Length;
572         ++I;
573       }
574     }
575 
576     if (!CurTypesSection.empty()) {
577       if (CurTypesSection.size() != 1)
578         return make_error<DWPError>("multiple type unit sections in .dwp file");
579       DWARFUnitIndex TUIndex(DW_SECT_TYPES);
580       DataExtractor TUIndexData(CurTUIndexSection, Obj.isLittleEndian(), 0);
581       if (!TUIndex.parse(TUIndexData))
582         return make_error<DWPError>("Failed to parse tu_index");
583       addAllTypesFromDWP(Out, TypeIndexEntries, TUIndex, TypesSection,
584                          CurTypesSection.front(), CurEntry,
585                          ContributionOffsets[DW_SECT_TYPES - DW_SECT_INFO]);
586     }
587   }
588 
589   // Lie about there being no info contributions so the TU index only includes
590   // the type unit contribution
591   ContributionOffsets[0] = 0;
592   writeIndex(Out, MCOFI.getDwarfTUIndexSection(), ContributionOffsets,
593              TypeIndexEntries);
594 
595   // Lie about the type contribution
596   ContributionOffsets[DW_SECT_TYPES - DW_SECT_INFO] = 0;
597   // Unlie about the info contribution
598   ContributionOffsets[0] = 1;
599 
600   writeIndex(Out, MCOFI.getDwarfCUIndexSection(), ContributionOffsets,
601              IndexEntries);
602 
603   return Error();
604 }
605 
error(const Twine & Error,const Twine & Context)606 static int error(const Twine &Error, const Twine &Context) {
607   errs() << Twine("while processing ") + Context + ":\n";
608   errs() << Twine("error: ") + Error + "\n";
609   return 1;
610 }
611 
main(int argc,char ** argv)612 int main(int argc, char **argv) {
613 
614   ParseCommandLineOptions(argc, argv, "merge split dwarf (.dwo) files");
615 
616   llvm::InitializeAllTargetInfos();
617   llvm::InitializeAllTargetMCs();
618   llvm::InitializeAllTargets();
619   llvm::InitializeAllAsmPrinters();
620 
621   std::string ErrorStr;
622   StringRef Context = "dwarf streamer init";
623 
624   Triple TheTriple("x86_64-linux-gnu");
625 
626   // Get the target.
627   const Target *TheTarget =
628       TargetRegistry::lookupTarget("", TheTriple, ErrorStr);
629   if (!TheTarget)
630     return error(ErrorStr, Context);
631   std::string TripleName = TheTriple.getTriple();
632 
633   // Create all the MC Objects.
634   std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
635   if (!MRI)
636     return error(Twine("no register info for target ") + TripleName, Context);
637 
638   std::unique_ptr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, TripleName));
639   if (!MAI)
640     return error("no asm info for target " + TripleName, Context);
641 
642   MCObjectFileInfo MOFI;
643   MCContext MC(MAI.get(), MRI.get(), &MOFI);
644   MOFI.InitMCObjectFileInfo(TheTriple, /*PIC*/ false, CodeModel::Default, MC);
645 
646   auto MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, "");
647   if (!MAB)
648     return error("no asm backend for target " + TripleName, Context);
649 
650   std::unique_ptr<MCInstrInfo> MII(TheTarget->createMCInstrInfo());
651   if (!MII)
652     return error("no instr info info for target " + TripleName, Context);
653 
654   std::unique_ptr<MCSubtargetInfo> MSTI(
655       TheTarget->createMCSubtargetInfo(TripleName, "", ""));
656   if (!MSTI)
657     return error("no subtarget info for target " + TripleName, Context);
658 
659   MCCodeEmitter *MCE = TheTarget->createMCCodeEmitter(*MII, *MRI, MC);
660   if (!MCE)
661     return error("no code emitter for target " + TripleName, Context);
662 
663   // Create the output file.
664   std::error_code EC;
665   raw_fd_ostream OutFile(OutputFilename, EC, sys::fs::F_None);
666   if (EC)
667     return error(Twine(OutputFilename) + ": " + EC.message(), Context);
668 
669   MCTargetOptions MCOptions = InitMCTargetOptionsFromFlags();
670   std::unique_ptr<MCStreamer> MS(TheTarget->createMCObjectStreamer(
671       TheTriple, MC, *MAB, OutFile, MCE, *MSTI, MCOptions.MCRelaxAll,
672       MCOptions.MCIncrementalLinkerCompatible,
673       /*DWARFMustBeAtTheEnd*/ false));
674   if (!MS)
675     return error("no object streamer for target " + TripleName, Context);
676 
677   if (auto Err = write(*MS, InputFiles)) {
678     logAllUnhandledErrors(std::move(Err), errs(), "error: ");
679     return 1;
680   }
681 
682   MS->Finish();
683 }
684