1 //===- DWARFContext.cpp ---------------------------------------------------===//
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 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
10 #include "llvm/ADT/STLExtras.h"
11 #include "llvm/ADT/SmallString.h"
12 #include "llvm/ADT/SmallVector.h"
13 #include "llvm/ADT/StringRef.h"
14 #include "llvm/ADT/StringSwitch.h"
15 #include "llvm/BinaryFormat/Dwarf.h"
16 #include "llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h"
17 #include "llvm/DebugInfo/DWARF/DWARFCompileUnit.h"
18 #include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
19 #include "llvm/DebugInfo/DWARF/DWARFDebugAddr.h"
20 #include "llvm/DebugInfo/DWARF/DWARFDebugArangeSet.h"
21 #include "llvm/DebugInfo/DWARF/DWARFDebugAranges.h"
22 #include "llvm/DebugInfo/DWARF/DWARFDebugFrame.h"
23 #include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
24 #include "llvm/DebugInfo/DWARF/DWARFDebugLoc.h"
25 #include "llvm/DebugInfo/DWARF/DWARFDebugMacro.h"
26 #include "llvm/DebugInfo/DWARF/DWARFDebugPubTable.h"
27 #include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
28 #include "llvm/DebugInfo/DWARF/DWARFDebugRnglists.h"
29 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
30 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
31 #include "llvm/DebugInfo/DWARF/DWARFGdbIndex.h"
32 #include "llvm/DebugInfo/DWARF/DWARFSection.h"
33 #include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
34 #include "llvm/DebugInfo/DWARF/DWARFVerifier.h"
35 #include "llvm/MC/MCRegisterInfo.h"
36 #include "llvm/Object/Decompressor.h"
37 #include "llvm/Object/MachO.h"
38 #include "llvm/Object/ObjectFile.h"
39 #include "llvm/Object/RelocationResolver.h"
40 #include "llvm/Support/Casting.h"
41 #include "llvm/Support/DataExtractor.h"
42 #include "llvm/Support/Error.h"
43 #include "llvm/Support/Format.h"
44 #include "llvm/Support/LEB128.h"
45 #include "llvm/Support/MemoryBuffer.h"
46 #include "llvm/Support/Path.h"
47 #include "llvm/Support/TargetRegistry.h"
48 #include "llvm/Support/raw_ostream.h"
49 #include <algorithm>
50 #include <cstdint>
51 #include <deque>
52 #include <map>
53 #include <string>
54 #include <utility>
55 #include <vector>
56 
57 using namespace llvm;
58 using namespace dwarf;
59 using namespace object;
60 
61 #define DEBUG_TYPE "dwarf"
62 
63 using DWARFLineTable = DWARFDebugLine::LineTable;
64 using FileLineInfoKind = DILineInfoSpecifier::FileLineInfoKind;
65 using FunctionNameKind = DILineInfoSpecifier::FunctionNameKind;
66 
67 DWARFContext::DWARFContext(std::unique_ptr<const DWARFObject> DObj,
68                            std::string DWPName,
69                            std::function<void(Error)> RecoverableErrorHandler,
70                            std::function<void(Error)> WarningHandler)
71     : DIContext(CK_DWARF), DWPName(std::move(DWPName)),
72       RecoverableErrorHandler(RecoverableErrorHandler),
73       WarningHandler(WarningHandler), DObj(std::move(DObj)) {}
74 
75 DWARFContext::~DWARFContext() = default;
76 
77 /// Dump the UUID load command.
78 static void dumpUUID(raw_ostream &OS, const ObjectFile &Obj) {
79   auto *MachO = dyn_cast<MachOObjectFile>(&Obj);
80   if (!MachO)
81     return;
82   for (auto LC : MachO->load_commands()) {
83     raw_ostream::uuid_t UUID;
84     if (LC.C.cmd == MachO::LC_UUID) {
85       if (LC.C.cmdsize < sizeof(UUID) + sizeof(LC.C)) {
86         OS << "error: UUID load command is too short.\n";
87         return;
88       }
89       OS << "UUID: ";
90       memcpy(&UUID, LC.Ptr+sizeof(LC.C), sizeof(UUID));
91       OS.write_uuid(UUID);
92       Triple T = MachO->getArchTriple();
93       OS << " (" << T.getArchName() << ')';
94       OS << ' ' << MachO->getFileName() << '\n';
95     }
96   }
97 }
98 
99 using ContributionCollection =
100     std::vector<Optional<StrOffsetsContributionDescriptor>>;
101 
102 // Collect all the contributions to the string offsets table from all units,
103 // sort them by their starting offsets and remove duplicates.
104 static ContributionCollection
105 collectContributionData(DWARFContext::unit_iterator_range Units) {
106   ContributionCollection Contributions;
107   for (const auto &U : Units)
108     if (const auto &C = U->getStringOffsetsTableContribution())
109       Contributions.push_back(C);
110   // Sort the contributions so that any invalid ones are placed at
111   // the start of the contributions vector. This way they are reported
112   // first.
113   llvm::sort(Contributions,
114              [](const Optional<StrOffsetsContributionDescriptor> &L,
115                 const Optional<StrOffsetsContributionDescriptor> &R) {
116                if (L && R)
117                  return L->Base < R->Base;
118                return R.hasValue();
119              });
120 
121   // Uniquify contributions, as it is possible that units (specifically
122   // type units in dwo or dwp files) share contributions. We don't want
123   // to report them more than once.
124   Contributions.erase(
125       std::unique(Contributions.begin(), Contributions.end(),
126                   [](const Optional<StrOffsetsContributionDescriptor> &L,
127                      const Optional<StrOffsetsContributionDescriptor> &R) {
128                     if (L && R)
129                       return L->Base == R->Base && L->Size == R->Size;
130                     return false;
131                   }),
132       Contributions.end());
133   return Contributions;
134 }
135 
136 // Dump a DWARF string offsets section. This may be a DWARF v5 formatted
137 // string offsets section, where each compile or type unit contributes a
138 // number of entries (string offsets), with each contribution preceded by
139 // a header containing size and version number. Alternatively, it may be a
140 // monolithic series of string offsets, as generated by the pre-DWARF v5
141 // implementation of split DWARF; however, in that case we still need to
142 // collect contributions of units because the size of the offsets (4 or 8
143 // bytes) depends on the format of the referencing unit (DWARF32 or DWARF64).
144 static void dumpStringOffsetsSection(raw_ostream &OS, DIDumpOptions DumpOpts,
145                                      StringRef SectionName,
146                                      const DWARFObject &Obj,
147                                      const DWARFSection &StringOffsetsSection,
148                                      StringRef StringSection,
149                                      DWARFContext::unit_iterator_range Units,
150                                      bool LittleEndian) {
151   auto Contributions = collectContributionData(Units);
152   DWARFDataExtractor StrOffsetExt(Obj, StringOffsetsSection, LittleEndian, 0);
153   DataExtractor StrData(StringSection, LittleEndian, 0);
154   uint64_t SectionSize = StringOffsetsSection.Data.size();
155   uint64_t Offset = 0;
156   for (auto &Contribution : Contributions) {
157     // Report an ill-formed contribution.
158     if (!Contribution) {
159       OS << "error: invalid contribution to string offsets table in section ."
160          << SectionName << ".\n";
161       return;
162     }
163 
164     dwarf::DwarfFormat Format = Contribution->getFormat();
165     int OffsetDumpWidth = 2 * dwarf::getDwarfOffsetByteSize(Format);
166     uint16_t Version = Contribution->getVersion();
167     uint64_t ContributionHeader = Contribution->Base;
168     // In DWARF v5 there is a contribution header that immediately precedes
169     // the string offsets base (the location we have previously retrieved from
170     // the CU DIE's DW_AT_str_offsets attribute). The header is located either
171     // 8 or 16 bytes before the base, depending on the contribution's format.
172     if (Version >= 5)
173       ContributionHeader -= Format == DWARF32 ? 8 : 16;
174 
175     // Detect overlapping contributions.
176     if (Offset > ContributionHeader) {
177       DumpOpts.RecoverableErrorHandler(createStringError(
178           errc::invalid_argument,
179           "overlapping contributions to string offsets table in section .%s.",
180           SectionName.data()));
181     }
182     // Report a gap in the table.
183     if (Offset < ContributionHeader) {
184       OS << format("0x%8.8" PRIx64 ": Gap, length = ", Offset);
185       OS << (ContributionHeader - Offset) << "\n";
186     }
187     OS << format("0x%8.8" PRIx64 ": ", ContributionHeader);
188     // In DWARF v5 the contribution size in the descriptor does not equal
189     // the originally encoded length (it does not contain the length of the
190     // version field and the padding, a total of 4 bytes). Add them back in
191     // for reporting.
192     OS << "Contribution size = " << (Contribution->Size + (Version < 5 ? 0 : 4))
193        << ", Format = " << dwarf::FormatString(Format)
194        << ", Version = " << Version << "\n";
195 
196     Offset = Contribution->Base;
197     unsigned EntrySize = Contribution->getDwarfOffsetByteSize();
198     while (Offset - Contribution->Base < Contribution->Size) {
199       OS << format("0x%8.8" PRIx64 ": ", Offset);
200       uint64_t StringOffset =
201           StrOffsetExt.getRelocatedValue(EntrySize, &Offset);
202       OS << format("%0*" PRIx64 " ", OffsetDumpWidth, StringOffset);
203       const char *S = StrData.getCStr(&StringOffset);
204       if (S)
205         OS << format("\"%s\"", S);
206       OS << "\n";
207     }
208   }
209   // Report a gap at the end of the table.
210   if (Offset < SectionSize) {
211     OS << format("0x%8.8" PRIx64 ": Gap, length = ", Offset);
212     OS << (SectionSize - Offset) << "\n";
213   }
214 }
215 
216 // Dump the .debug_addr section.
217 static void dumpAddrSection(raw_ostream &OS, DWARFDataExtractor &AddrData,
218                             DIDumpOptions DumpOpts, uint16_t Version,
219                             uint8_t AddrSize) {
220   uint64_t Offset = 0;
221   while (AddrData.isValidOffset(Offset)) {
222     DWARFDebugAddrTable AddrTable;
223     uint64_t TableOffset = Offset;
224     if (Error Err = AddrTable.extract(AddrData, &Offset, Version, AddrSize,
225                                       DumpOpts.WarningHandler)) {
226       DumpOpts.RecoverableErrorHandler(std::move(Err));
227       // Keep going after an error, if we can, assuming that the length field
228       // could be read. If it couldn't, stop reading the section.
229       if (auto TableLength = AddrTable.getFullLength()) {
230         Offset = TableOffset + *TableLength;
231         continue;
232       }
233       break;
234     }
235     AddrTable.dump(OS, DumpOpts);
236   }
237 }
238 
239 // Dump the .debug_rnglists or .debug_rnglists.dwo section (DWARF v5).
240 static void dumpRnglistsSection(
241     raw_ostream &OS, DWARFDataExtractor &rnglistData,
242     llvm::function_ref<Optional<object::SectionedAddress>(uint32_t)>
243         LookupPooledAddress,
244     DIDumpOptions DumpOpts) {
245   uint64_t Offset = 0;
246   while (rnglistData.isValidOffset(Offset)) {
247     llvm::DWARFDebugRnglistTable Rnglists;
248     uint64_t TableOffset = Offset;
249     if (Error Err = Rnglists.extract(rnglistData, &Offset)) {
250       DumpOpts.RecoverableErrorHandler(std::move(Err));
251       uint64_t Length = Rnglists.length();
252       // Keep going after an error, if we can, assuming that the length field
253       // could be read. If it couldn't, stop reading the section.
254       if (Length == 0)
255         break;
256       Offset = TableOffset + Length;
257     } else {
258       Rnglists.dump(rnglistData, OS, LookupPooledAddress, DumpOpts);
259     }
260   }
261 }
262 
263 std::unique_ptr<DWARFDebugMacro>
264 DWARFContext::parseMacroOrMacinfo(MacroSecType SectionType) {
265   auto Macro = std::make_unique<DWARFDebugMacro>();
266   auto ParseAndDump = [&](DWARFDataExtractor &Data, bool IsMacro) {
267     if (Error Err = IsMacro ? Macro->parseMacro(SectionType == MacroSection
268                                                     ? compile_units()
269                                                     : dwo_compile_units(),
270                                                 SectionType == MacroSection
271                                                     ? getStringExtractor()
272                                                     : getStringDWOExtractor(),
273                                                 Data)
274                             : Macro->parseMacinfo(Data)) {
275       RecoverableErrorHandler(std::move(Err));
276       Macro = nullptr;
277     }
278   };
279   switch (SectionType) {
280   case MacinfoSection: {
281     DWARFDataExtractor Data(DObj->getMacinfoSection(), isLittleEndian(), 0);
282     ParseAndDump(Data, /*IsMacro=*/false);
283     break;
284   }
285   case MacinfoDwoSection: {
286     DWARFDataExtractor Data(DObj->getMacinfoDWOSection(), isLittleEndian(), 0);
287     ParseAndDump(Data, /*IsMacro=*/false);
288     break;
289   }
290   case MacroSection: {
291     DWARFDataExtractor Data(*DObj, DObj->getMacroSection(), isLittleEndian(),
292                             0);
293     ParseAndDump(Data, /*IsMacro=*/true);
294     break;
295   }
296   case MacroDwoSection: {
297     DWARFDataExtractor Data(DObj->getMacroDWOSection(), isLittleEndian(), 0);
298     ParseAndDump(Data, /*IsMacro=*/true);
299     break;
300   }
301   }
302   return Macro;
303 }
304 
305 static void dumpLoclistsSection(raw_ostream &OS, DIDumpOptions DumpOpts,
306                                 DWARFDataExtractor Data,
307                                 const MCRegisterInfo *MRI,
308                                 const DWARFObject &Obj,
309                                 Optional<uint64_t> DumpOffset) {
310   uint64_t Offset = 0;
311 
312   while (Data.isValidOffset(Offset)) {
313     DWARFListTableHeader Header(".debug_loclists", "locations");
314     if (Error E = Header.extract(Data, &Offset)) {
315       DumpOpts.RecoverableErrorHandler(std::move(E));
316       return;
317     }
318 
319     Header.dump(Data, OS, DumpOpts);
320 
321     uint64_t EndOffset = Header.length() + Header.getHeaderOffset();
322     Data.setAddressSize(Header.getAddrSize());
323     DWARFDebugLoclists Loc(Data, Header.getVersion());
324     if (DumpOffset) {
325       if (DumpOffset >= Offset && DumpOffset < EndOffset) {
326         Offset = *DumpOffset;
327         Loc.dumpLocationList(&Offset, OS, /*BaseAddr=*/None, MRI, Obj, nullptr,
328                              DumpOpts, /*Indent=*/0);
329         OS << "\n";
330         return;
331       }
332     } else {
333       Loc.dumpRange(Offset, EndOffset - Offset, OS, MRI, Obj, DumpOpts);
334     }
335     Offset = EndOffset;
336   }
337 }
338 
339 static void dumpPubTableSection(raw_ostream &OS, DIDumpOptions DumpOpts,
340                                 DWARFDataExtractor Data, bool GnuStyle) {
341   DWARFDebugPubTable Table;
342   Table.extract(Data, GnuStyle, DumpOpts.RecoverableErrorHandler);
343   Table.dump(OS);
344 }
345 
346 void DWARFContext::dump(
347     raw_ostream &OS, DIDumpOptions DumpOpts,
348     std::array<Optional<uint64_t>, DIDT_ID_Count> DumpOffsets) {
349   uint64_t DumpType = DumpOpts.DumpType;
350 
351   StringRef Extension = sys::path::extension(DObj->getFileName());
352   bool IsDWO = (Extension == ".dwo") || (Extension == ".dwp");
353 
354   // Print UUID header.
355   const auto *ObjFile = DObj->getFile();
356   if (DumpType & DIDT_UUID)
357     dumpUUID(OS, *ObjFile);
358 
359   // Print a header for each explicitly-requested section.
360   // Otherwise just print one for non-empty sections.
361   // Only print empty .dwo section headers when dumping a .dwo file.
362   bool Explicit = DumpType != DIDT_All && !IsDWO;
363   bool ExplicitDWO = Explicit && IsDWO;
364   auto shouldDump = [&](bool Explicit, const char *Name, unsigned ID,
365                         StringRef Section) -> Optional<uint64_t> * {
366     unsigned Mask = 1U << ID;
367     bool Should = (DumpType & Mask) && (Explicit || !Section.empty());
368     if (!Should)
369       return nullptr;
370     OS << "\n" << Name << " contents:\n";
371     return &DumpOffsets[ID];
372   };
373 
374   // Dump individual sections.
375   if (shouldDump(Explicit, ".debug_abbrev", DIDT_ID_DebugAbbrev,
376                  DObj->getAbbrevSection()))
377     getDebugAbbrev()->dump(OS);
378   if (shouldDump(ExplicitDWO, ".debug_abbrev.dwo", DIDT_ID_DebugAbbrev,
379                  DObj->getAbbrevDWOSection()))
380     getDebugAbbrevDWO()->dump(OS);
381 
382   auto dumpDebugInfo = [&](const char *Name, unit_iterator_range Units) {
383     OS << '\n' << Name << " contents:\n";
384     if (auto DumpOffset = DumpOffsets[DIDT_ID_DebugInfo])
385       for (const auto &U : Units)
386         U->getDIEForOffset(DumpOffset.getValue())
387             .dump(OS, 0, DumpOpts.noImplicitRecursion());
388     else
389       for (const auto &U : Units)
390         U->dump(OS, DumpOpts);
391   };
392   if ((DumpType & DIDT_DebugInfo)) {
393     if (Explicit || getNumCompileUnits())
394       dumpDebugInfo(".debug_info", info_section_units());
395     if (ExplicitDWO || getNumDWOCompileUnits())
396       dumpDebugInfo(".debug_info.dwo", dwo_info_section_units());
397   }
398 
399   auto dumpDebugType = [&](const char *Name, unit_iterator_range Units) {
400     OS << '\n' << Name << " contents:\n";
401     for (const auto &U : Units)
402       if (auto DumpOffset = DumpOffsets[DIDT_ID_DebugTypes])
403         U->getDIEForOffset(*DumpOffset)
404             .dump(OS, 0, DumpOpts.noImplicitRecursion());
405       else
406         U->dump(OS, DumpOpts);
407   };
408   if ((DumpType & DIDT_DebugTypes)) {
409     if (Explicit || getNumTypeUnits())
410       dumpDebugType(".debug_types", types_section_units());
411     if (ExplicitDWO || getNumDWOTypeUnits())
412       dumpDebugType(".debug_types.dwo", dwo_types_section_units());
413   }
414 
415   DIDumpOptions LLDumpOpts = DumpOpts;
416   if (LLDumpOpts.Verbose)
417     LLDumpOpts.DisplayRawContents = true;
418 
419   if (const auto *Off = shouldDump(Explicit, ".debug_loc", DIDT_ID_DebugLoc,
420                                    DObj->getLocSection().Data)) {
421     getDebugLoc()->dump(OS, getRegisterInfo(), *DObj, LLDumpOpts, *Off);
422   }
423   if (const auto *Off =
424           shouldDump(Explicit, ".debug_loclists", DIDT_ID_DebugLoclists,
425                      DObj->getLoclistsSection().Data)) {
426     DWARFDataExtractor Data(*DObj, DObj->getLoclistsSection(), isLittleEndian(),
427                             0);
428     dumpLoclistsSection(OS, LLDumpOpts, Data, getRegisterInfo(), *DObj, *Off);
429   }
430   if (const auto *Off =
431           shouldDump(ExplicitDWO, ".debug_loclists.dwo", DIDT_ID_DebugLoclists,
432                      DObj->getLoclistsDWOSection().Data)) {
433     DWARFDataExtractor Data(*DObj, DObj->getLoclistsDWOSection(),
434                             isLittleEndian(), 0);
435     dumpLoclistsSection(OS, LLDumpOpts, Data, getRegisterInfo(), *DObj, *Off);
436   }
437 
438   if (const auto *Off =
439           shouldDump(ExplicitDWO, ".debug_loc.dwo", DIDT_ID_DebugLoc,
440                      DObj->getLocDWOSection().Data)) {
441     DWARFDataExtractor Data(*DObj, DObj->getLocDWOSection(), isLittleEndian(),
442                             4);
443     DWARFDebugLoclists Loc(Data, /*Version=*/4);
444     if (*Off) {
445       uint64_t Offset = **Off;
446       Loc.dumpLocationList(&Offset, OS,
447                            /*BaseAddr=*/None, getRegisterInfo(), *DObj, nullptr,
448                            LLDumpOpts, /*Indent=*/0);
449       OS << "\n";
450     } else {
451       Loc.dumpRange(0, Data.getData().size(), OS, getRegisterInfo(), *DObj,
452                     LLDumpOpts);
453     }
454   }
455 
456   if (const Optional<uint64_t> *Off =
457           shouldDump(Explicit, ".debug_frame", DIDT_ID_DebugFrame,
458                      DObj->getFrameSection().Data)) {
459     if (Expected<const DWARFDebugFrame *> DF = getDebugFrame())
460       (*DF)->dump(OS, DumpOpts, getRegisterInfo(), *Off);
461     else
462       RecoverableErrorHandler(DF.takeError());
463   }
464 
465   if (const Optional<uint64_t> *Off =
466           shouldDump(Explicit, ".eh_frame", DIDT_ID_DebugFrame,
467                      DObj->getEHFrameSection().Data)) {
468     if (Expected<const DWARFDebugFrame *> DF = getEHFrame())
469       (*DF)->dump(OS, DumpOpts, getRegisterInfo(), *Off);
470     else
471       RecoverableErrorHandler(DF.takeError());
472   }
473 
474   if (shouldDump(Explicit, ".debug_macro", DIDT_ID_DebugMacro,
475                  DObj->getMacroSection().Data)) {
476     if (auto Macro = getDebugMacro())
477       Macro->dump(OS);
478   }
479 
480   if (shouldDump(Explicit, ".debug_macro.dwo", DIDT_ID_DebugMacro,
481                  DObj->getMacroDWOSection())) {
482     if (auto MacroDWO = getDebugMacroDWO())
483       MacroDWO->dump(OS);
484   }
485 
486   if (shouldDump(Explicit, ".debug_macinfo", DIDT_ID_DebugMacro,
487                  DObj->getMacinfoSection())) {
488     if (auto Macinfo = getDebugMacinfo())
489       Macinfo->dump(OS);
490   }
491 
492   if (shouldDump(Explicit, ".debug_macinfo.dwo", DIDT_ID_DebugMacro,
493                  DObj->getMacinfoDWOSection())) {
494     if (auto MacinfoDWO = getDebugMacinfoDWO())
495       MacinfoDWO->dump(OS);
496   }
497 
498   if (shouldDump(Explicit, ".debug_aranges", DIDT_ID_DebugAranges,
499                  DObj->getArangesSection())) {
500     uint64_t offset = 0;
501     DWARFDataExtractor arangesData(DObj->getArangesSection(), isLittleEndian(),
502                                    0);
503     DWARFDebugArangeSet set;
504     while (arangesData.isValidOffset(offset)) {
505       if (Error E =
506               set.extract(arangesData, &offset, DumpOpts.WarningHandler)) {
507         RecoverableErrorHandler(std::move(E));
508         break;
509       }
510       set.dump(OS);
511     }
512   }
513 
514   auto DumpLineSection = [&](DWARFDebugLine::SectionParser Parser,
515                              DIDumpOptions DumpOpts,
516                              Optional<uint64_t> DumpOffset) {
517     while (!Parser.done()) {
518       if (DumpOffset && Parser.getOffset() != *DumpOffset) {
519         Parser.skip(DumpOpts.WarningHandler, DumpOpts.WarningHandler);
520         continue;
521       }
522       OS << "debug_line[" << format("0x%8.8" PRIx64, Parser.getOffset())
523          << "]\n";
524       Parser.parseNext(DumpOpts.WarningHandler, DumpOpts.WarningHandler, &OS,
525                        DumpOpts.Verbose);
526     }
527   };
528 
529   auto DumpStrSection = [&](StringRef Section) {
530     DataExtractor StrData(Section, isLittleEndian(), 0);
531     uint64_t Offset = 0;
532     uint64_t StrOffset = 0;
533     while (StrData.isValidOffset(Offset)) {
534       Error Err = Error::success();
535       const char *CStr = StrData.getCStr(&Offset, &Err);
536       if (Err) {
537         DumpOpts.WarningHandler(std::move(Err));
538         return;
539       }
540       OS << format("0x%8.8" PRIx64 ": \"", StrOffset);
541       OS.write_escaped(CStr);
542       OS << "\"\n";
543       StrOffset = Offset;
544     }
545   };
546 
547   if (const auto *Off = shouldDump(Explicit, ".debug_line", DIDT_ID_DebugLine,
548                                    DObj->getLineSection().Data)) {
549     DWARFDataExtractor LineData(*DObj, DObj->getLineSection(), isLittleEndian(),
550                                 0);
551     DWARFDebugLine::SectionParser Parser(LineData, *this, normal_units());
552     DumpLineSection(Parser, DumpOpts, *Off);
553   }
554 
555   if (const auto *Off =
556           shouldDump(ExplicitDWO, ".debug_line.dwo", DIDT_ID_DebugLine,
557                      DObj->getLineDWOSection().Data)) {
558     DWARFDataExtractor LineData(*DObj, DObj->getLineDWOSection(),
559                                 isLittleEndian(), 0);
560     DWARFDebugLine::SectionParser Parser(LineData, *this, dwo_units());
561     DumpLineSection(Parser, DumpOpts, *Off);
562   }
563 
564   if (shouldDump(Explicit, ".debug_cu_index", DIDT_ID_DebugCUIndex,
565                  DObj->getCUIndexSection())) {
566     getCUIndex().dump(OS);
567   }
568 
569   if (shouldDump(Explicit, ".debug_tu_index", DIDT_ID_DebugTUIndex,
570                  DObj->getTUIndexSection())) {
571     getTUIndex().dump(OS);
572   }
573 
574   if (shouldDump(Explicit, ".debug_str", DIDT_ID_DebugStr,
575                  DObj->getStrSection()))
576     DumpStrSection(DObj->getStrSection());
577 
578   if (shouldDump(ExplicitDWO, ".debug_str.dwo", DIDT_ID_DebugStr,
579                  DObj->getStrDWOSection()))
580     DumpStrSection(DObj->getStrDWOSection());
581 
582   if (shouldDump(Explicit, ".debug_line_str", DIDT_ID_DebugLineStr,
583                  DObj->getLineStrSection()))
584     DumpStrSection(DObj->getLineStrSection());
585 
586   if (shouldDump(Explicit, ".debug_addr", DIDT_ID_DebugAddr,
587                  DObj->getAddrSection().Data)) {
588     DWARFDataExtractor AddrData(*DObj, DObj->getAddrSection(),
589                                    isLittleEndian(), 0);
590     dumpAddrSection(OS, AddrData, DumpOpts, getMaxVersion(), getCUAddrSize());
591   }
592 
593   if (shouldDump(Explicit, ".debug_ranges", DIDT_ID_DebugRanges,
594                  DObj->getRangesSection().Data)) {
595     uint8_t savedAddressByteSize = getCUAddrSize();
596     DWARFDataExtractor rangesData(*DObj, DObj->getRangesSection(),
597                                   isLittleEndian(), savedAddressByteSize);
598     uint64_t offset = 0;
599     DWARFDebugRangeList rangeList;
600     while (rangesData.isValidOffset(offset)) {
601       if (Error E = rangeList.extract(rangesData, &offset)) {
602         DumpOpts.RecoverableErrorHandler(std::move(E));
603         break;
604       }
605       rangeList.dump(OS);
606     }
607   }
608 
609   auto LookupPooledAddress = [&](uint32_t Index) -> Optional<SectionedAddress> {
610     const auto &CUs = compile_units();
611     auto I = CUs.begin();
612     if (I == CUs.end())
613       return None;
614     return (*I)->getAddrOffsetSectionItem(Index);
615   };
616 
617   if (shouldDump(Explicit, ".debug_rnglists", DIDT_ID_DebugRnglists,
618                  DObj->getRnglistsSection().Data)) {
619     DWARFDataExtractor RnglistData(*DObj, DObj->getRnglistsSection(),
620                                    isLittleEndian(), 0);
621     dumpRnglistsSection(OS, RnglistData, LookupPooledAddress, DumpOpts);
622   }
623 
624   if (shouldDump(ExplicitDWO, ".debug_rnglists.dwo", DIDT_ID_DebugRnglists,
625                  DObj->getRnglistsDWOSection().Data)) {
626     DWARFDataExtractor RnglistData(*DObj, DObj->getRnglistsDWOSection(),
627                                    isLittleEndian(), 0);
628     dumpRnglistsSection(OS, RnglistData, LookupPooledAddress, DumpOpts);
629   }
630 
631   if (shouldDump(Explicit, ".debug_pubnames", DIDT_ID_DebugPubnames,
632                  DObj->getPubnamesSection().Data)) {
633     DWARFDataExtractor PubTableData(*DObj, DObj->getPubnamesSection(),
634                                     isLittleEndian(), 0);
635     dumpPubTableSection(OS, DumpOpts, PubTableData, /*GnuStyle=*/false);
636   }
637 
638   if (shouldDump(Explicit, ".debug_pubtypes", DIDT_ID_DebugPubtypes,
639                  DObj->getPubtypesSection().Data)) {
640     DWARFDataExtractor PubTableData(*DObj, DObj->getPubtypesSection(),
641                                     isLittleEndian(), 0);
642     dumpPubTableSection(OS, DumpOpts, PubTableData, /*GnuStyle=*/false);
643   }
644 
645   if (shouldDump(Explicit, ".debug_gnu_pubnames", DIDT_ID_DebugGnuPubnames,
646                  DObj->getGnuPubnamesSection().Data)) {
647     DWARFDataExtractor PubTableData(*DObj, DObj->getGnuPubnamesSection(),
648                                     isLittleEndian(), 0);
649     dumpPubTableSection(OS, DumpOpts, PubTableData, /*GnuStyle=*/true);
650   }
651 
652   if (shouldDump(Explicit, ".debug_gnu_pubtypes", DIDT_ID_DebugGnuPubtypes,
653                  DObj->getGnuPubtypesSection().Data)) {
654     DWARFDataExtractor PubTableData(*DObj, DObj->getGnuPubtypesSection(),
655                                     isLittleEndian(), 0);
656     dumpPubTableSection(OS, DumpOpts, PubTableData, /*GnuStyle=*/true);
657   }
658 
659   if (shouldDump(Explicit, ".debug_str_offsets", DIDT_ID_DebugStrOffsets,
660                  DObj->getStrOffsetsSection().Data))
661     dumpStringOffsetsSection(
662         OS, DumpOpts, "debug_str_offsets", *DObj, DObj->getStrOffsetsSection(),
663         DObj->getStrSection(), normal_units(), isLittleEndian());
664   if (shouldDump(ExplicitDWO, ".debug_str_offsets.dwo", DIDT_ID_DebugStrOffsets,
665                  DObj->getStrOffsetsDWOSection().Data))
666     dumpStringOffsetsSection(OS, DumpOpts, "debug_str_offsets.dwo", *DObj,
667                              DObj->getStrOffsetsDWOSection(),
668                              DObj->getStrDWOSection(), dwo_units(),
669                              isLittleEndian());
670 
671   if (shouldDump(Explicit, ".gdb_index", DIDT_ID_GdbIndex,
672                  DObj->getGdbIndexSection())) {
673     getGdbIndex().dump(OS);
674   }
675 
676   if (shouldDump(Explicit, ".apple_names", DIDT_ID_AppleNames,
677                  DObj->getAppleNamesSection().Data))
678     getAppleNames().dump(OS);
679 
680   if (shouldDump(Explicit, ".apple_types", DIDT_ID_AppleTypes,
681                  DObj->getAppleTypesSection().Data))
682     getAppleTypes().dump(OS);
683 
684   if (shouldDump(Explicit, ".apple_namespaces", DIDT_ID_AppleNamespaces,
685                  DObj->getAppleNamespacesSection().Data))
686     getAppleNamespaces().dump(OS);
687 
688   if (shouldDump(Explicit, ".apple_objc", DIDT_ID_AppleObjC,
689                  DObj->getAppleObjCSection().Data))
690     getAppleObjC().dump(OS);
691   if (shouldDump(Explicit, ".debug_names", DIDT_ID_DebugNames,
692                  DObj->getNamesSection().Data))
693     getDebugNames().dump(OS);
694 }
695 
696 DWARFCompileUnit *DWARFContext::getDWOCompileUnitForHash(uint64_t Hash) {
697   parseDWOUnits(LazyParse);
698 
699   if (const auto &CUI = getCUIndex()) {
700     if (const auto *R = CUI.getFromHash(Hash))
701       return dyn_cast_or_null<DWARFCompileUnit>(
702           DWOUnits.getUnitForIndexEntry(*R));
703     return nullptr;
704   }
705 
706   // If there's no index, just search through the CUs in the DWO - there's
707   // probably only one unless this is something like LTO - though an in-process
708   // built/cached lookup table could be used in that case to improve repeated
709   // lookups of different CUs in the DWO.
710   for (const auto &DWOCU : dwo_compile_units()) {
711     // Might not have parsed DWO ID yet.
712     if (!DWOCU->getDWOId()) {
713       if (Optional<uint64_t> DWOId =
714           toUnsigned(DWOCU->getUnitDIE().find(DW_AT_GNU_dwo_id)))
715         DWOCU->setDWOId(*DWOId);
716       else
717         // No DWO ID?
718         continue;
719     }
720     if (DWOCU->getDWOId() == Hash)
721       return dyn_cast<DWARFCompileUnit>(DWOCU.get());
722   }
723   return nullptr;
724 }
725 
726 DWARFDie DWARFContext::getDIEForOffset(uint64_t Offset) {
727   parseNormalUnits();
728   if (auto *CU = NormalUnits.getUnitForOffset(Offset))
729     return CU->getDIEForOffset(Offset);
730   return DWARFDie();
731 }
732 
733 bool DWARFContext::verify(raw_ostream &OS, DIDumpOptions DumpOpts) {
734   bool Success = true;
735   DWARFVerifier verifier(OS, *this, DumpOpts);
736 
737   Success &= verifier.handleDebugAbbrev();
738   if (DumpOpts.DumpType & DIDT_DebugInfo)
739     Success &= verifier.handleDebugInfo();
740   if (DumpOpts.DumpType & DIDT_DebugLine)
741     Success &= verifier.handleDebugLine();
742   Success &= verifier.handleAccelTables();
743   return Success;
744 }
745 
746 const DWARFUnitIndex &DWARFContext::getCUIndex() {
747   if (CUIndex)
748     return *CUIndex;
749 
750   DataExtractor CUIndexData(DObj->getCUIndexSection(), isLittleEndian(), 0);
751 
752   CUIndex = std::make_unique<DWARFUnitIndex>(DW_SECT_INFO);
753   CUIndex->parse(CUIndexData);
754   return *CUIndex;
755 }
756 
757 const DWARFUnitIndex &DWARFContext::getTUIndex() {
758   if (TUIndex)
759     return *TUIndex;
760 
761   DataExtractor TUIndexData(DObj->getTUIndexSection(), isLittleEndian(), 0);
762 
763   TUIndex = std::make_unique<DWARFUnitIndex>(DW_SECT_EXT_TYPES);
764   TUIndex->parse(TUIndexData);
765   return *TUIndex;
766 }
767 
768 DWARFGdbIndex &DWARFContext::getGdbIndex() {
769   if (GdbIndex)
770     return *GdbIndex;
771 
772   DataExtractor GdbIndexData(DObj->getGdbIndexSection(), true /*LE*/, 0);
773   GdbIndex = std::make_unique<DWARFGdbIndex>();
774   GdbIndex->parse(GdbIndexData);
775   return *GdbIndex;
776 }
777 
778 const DWARFDebugAbbrev *DWARFContext::getDebugAbbrev() {
779   if (Abbrev)
780     return Abbrev.get();
781 
782   DataExtractor abbrData(DObj->getAbbrevSection(), isLittleEndian(), 0);
783 
784   Abbrev.reset(new DWARFDebugAbbrev());
785   Abbrev->extract(abbrData);
786   return Abbrev.get();
787 }
788 
789 const DWARFDebugAbbrev *DWARFContext::getDebugAbbrevDWO() {
790   if (AbbrevDWO)
791     return AbbrevDWO.get();
792 
793   DataExtractor abbrData(DObj->getAbbrevDWOSection(), isLittleEndian(), 0);
794   AbbrevDWO.reset(new DWARFDebugAbbrev());
795   AbbrevDWO->extract(abbrData);
796   return AbbrevDWO.get();
797 }
798 
799 const DWARFDebugLoc *DWARFContext::getDebugLoc() {
800   if (Loc)
801     return Loc.get();
802 
803   // Assume all units have the same address byte size.
804   auto LocData =
805       getNumCompileUnits()
806           ? DWARFDataExtractor(*DObj, DObj->getLocSection(), isLittleEndian(),
807                                getUnitAtIndex(0)->getAddressByteSize())
808           : DWARFDataExtractor("", isLittleEndian(), 0);
809   Loc.reset(new DWARFDebugLoc(std::move(LocData)));
810   return Loc.get();
811 }
812 
813 const DWARFDebugAranges *DWARFContext::getDebugAranges() {
814   if (Aranges)
815     return Aranges.get();
816 
817   Aranges.reset(new DWARFDebugAranges());
818   Aranges->generate(this);
819   return Aranges.get();
820 }
821 
822 Expected<const DWARFDebugFrame *> DWARFContext::getDebugFrame() {
823   if (DebugFrame)
824     return DebugFrame.get();
825 
826   // There's a "bug" in the DWARFv3 standard with respect to the target address
827   // size within debug frame sections. While DWARF is supposed to be independent
828   // of its container, FDEs have fields with size being "target address size",
829   // which isn't specified in DWARF in general. It's only specified for CUs, but
830   // .eh_frame can appear without a .debug_info section. Follow the example of
831   // other tools (libdwarf) and extract this from the container (ObjectFile
832   // provides this information). This problem is fixed in DWARFv4
833   // See this dwarf-discuss discussion for more details:
834   // http://lists.dwarfstd.org/htdig.cgi/dwarf-discuss-dwarfstd.org/2011-December/001173.html
835   DWARFDataExtractor debugFrameData(*DObj, DObj->getFrameSection(),
836                                     isLittleEndian(), DObj->getAddressSize());
837   auto DF = std::make_unique<DWARFDebugFrame>(getArch(), /*IsEH=*/false);
838   if (Error E = DF->parse(debugFrameData))
839     return std::move(E);
840 
841   DebugFrame.swap(DF);
842   return DebugFrame.get();
843 }
844 
845 Expected<const DWARFDebugFrame *> DWARFContext::getEHFrame() {
846   if (EHFrame)
847     return EHFrame.get();
848 
849   DWARFDataExtractor debugFrameData(*DObj, DObj->getEHFrameSection(),
850                                     isLittleEndian(), DObj->getAddressSize());
851 
852   auto DF = std::make_unique<DWARFDebugFrame>(getArch(), /*IsEH=*/true);
853   if (Error E = DF->parse(debugFrameData))
854     return std::move(E);
855   DebugFrame.swap(DF);
856   return DebugFrame.get();
857 }
858 
859 const DWARFDebugMacro *DWARFContext::getDebugMacro() {
860   if (!Macro)
861     Macro = parseMacroOrMacinfo(MacroSection);
862   return Macro.get();
863 }
864 
865 const DWARFDebugMacro *DWARFContext::getDebugMacroDWO() {
866   if (!MacroDWO)
867     MacroDWO = parseMacroOrMacinfo(MacroDwoSection);
868   return MacroDWO.get();
869 }
870 
871 const DWARFDebugMacro *DWARFContext::getDebugMacinfo() {
872   if (!Macinfo)
873     Macinfo = parseMacroOrMacinfo(MacinfoSection);
874   return Macinfo.get();
875 }
876 
877 const DWARFDebugMacro *DWARFContext::getDebugMacinfoDWO() {
878   if (!MacinfoDWO)
879     MacinfoDWO = parseMacroOrMacinfo(MacinfoDwoSection);
880   return MacinfoDWO.get();
881 }
882 
883 template <typename T>
884 static T &getAccelTable(std::unique_ptr<T> &Cache, const DWARFObject &Obj,
885                         const DWARFSection &Section, StringRef StringSection,
886                         bool IsLittleEndian) {
887   if (Cache)
888     return *Cache;
889   DWARFDataExtractor AccelSection(Obj, Section, IsLittleEndian, 0);
890   DataExtractor StrData(StringSection, IsLittleEndian, 0);
891   Cache.reset(new T(AccelSection, StrData));
892   if (Error E = Cache->extract())
893     llvm::consumeError(std::move(E));
894   return *Cache;
895 }
896 
897 const DWARFDebugNames &DWARFContext::getDebugNames() {
898   return getAccelTable(Names, *DObj, DObj->getNamesSection(),
899                        DObj->getStrSection(), isLittleEndian());
900 }
901 
902 const AppleAcceleratorTable &DWARFContext::getAppleNames() {
903   return getAccelTable(AppleNames, *DObj, DObj->getAppleNamesSection(),
904                        DObj->getStrSection(), isLittleEndian());
905 }
906 
907 const AppleAcceleratorTable &DWARFContext::getAppleTypes() {
908   return getAccelTable(AppleTypes, *DObj, DObj->getAppleTypesSection(),
909                        DObj->getStrSection(), isLittleEndian());
910 }
911 
912 const AppleAcceleratorTable &DWARFContext::getAppleNamespaces() {
913   return getAccelTable(AppleNamespaces, *DObj,
914                        DObj->getAppleNamespacesSection(),
915                        DObj->getStrSection(), isLittleEndian());
916 }
917 
918 const AppleAcceleratorTable &DWARFContext::getAppleObjC() {
919   return getAccelTable(AppleObjC, *DObj, DObj->getAppleObjCSection(),
920                        DObj->getStrSection(), isLittleEndian());
921 }
922 
923 const DWARFDebugLine::LineTable *
924 DWARFContext::getLineTableForUnit(DWARFUnit *U) {
925   Expected<const DWARFDebugLine::LineTable *> ExpectedLineTable =
926       getLineTableForUnit(U, WarningHandler);
927   if (!ExpectedLineTable) {
928     WarningHandler(ExpectedLineTable.takeError());
929     return nullptr;
930   }
931   return *ExpectedLineTable;
932 }
933 
934 Expected<const DWARFDebugLine::LineTable *> DWARFContext::getLineTableForUnit(
935     DWARFUnit *U, function_ref<void(Error)> RecoverableErrorHandler) {
936   if (!Line)
937     Line.reset(new DWARFDebugLine);
938 
939   auto UnitDIE = U->getUnitDIE();
940   if (!UnitDIE)
941     return nullptr;
942 
943   auto Offset = toSectionOffset(UnitDIE.find(DW_AT_stmt_list));
944   if (!Offset)
945     return nullptr; // No line table for this compile unit.
946 
947   uint64_t stmtOffset = *Offset + U->getLineTableOffset();
948   // See if the line table is cached.
949   if (const DWARFLineTable *lt = Line->getLineTable(stmtOffset))
950     return lt;
951 
952   // Make sure the offset is good before we try to parse.
953   if (stmtOffset >= U->getLineSection().Data.size())
954     return nullptr;
955 
956   // We have to parse it first.
957   DWARFDataExtractor lineData(*DObj, U->getLineSection(), isLittleEndian(),
958                               U->getAddressByteSize());
959   return Line->getOrParseLineTable(lineData, stmtOffset, *this, U,
960                                    RecoverableErrorHandler);
961 }
962 
963 void DWARFContext::parseNormalUnits() {
964   if (!NormalUnits.empty())
965     return;
966   DObj->forEachInfoSections([&](const DWARFSection &S) {
967     NormalUnits.addUnitsForSection(*this, S, DW_SECT_INFO);
968   });
969   NormalUnits.finishedInfoUnits();
970   DObj->forEachTypesSections([&](const DWARFSection &S) {
971     NormalUnits.addUnitsForSection(*this, S, DW_SECT_EXT_TYPES);
972   });
973 }
974 
975 void DWARFContext::parseDWOUnits(bool Lazy) {
976   if (!DWOUnits.empty())
977     return;
978   DObj->forEachInfoDWOSections([&](const DWARFSection &S) {
979     DWOUnits.addUnitsForDWOSection(*this, S, DW_SECT_INFO, Lazy);
980   });
981   DWOUnits.finishedInfoUnits();
982   DObj->forEachTypesDWOSections([&](const DWARFSection &S) {
983     DWOUnits.addUnitsForDWOSection(*this, S, DW_SECT_EXT_TYPES, Lazy);
984   });
985 }
986 
987 DWARFCompileUnit *DWARFContext::getCompileUnitForOffset(uint64_t Offset) {
988   parseNormalUnits();
989   return dyn_cast_or_null<DWARFCompileUnit>(
990       NormalUnits.getUnitForOffset(Offset));
991 }
992 
993 DWARFCompileUnit *DWARFContext::getCompileUnitForAddress(uint64_t Address) {
994   // First, get the offset of the compile unit.
995   uint64_t CUOffset = getDebugAranges()->findAddress(Address);
996   // Retrieve the compile unit.
997   return getCompileUnitForOffset(CUOffset);
998 }
999 
1000 DWARFContext::DIEsForAddress DWARFContext::getDIEsForAddress(uint64_t Address) {
1001   DIEsForAddress Result;
1002 
1003   DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
1004   if (!CU)
1005     return Result;
1006 
1007   Result.CompileUnit = CU;
1008   Result.FunctionDIE = CU->getSubroutineForAddress(Address);
1009 
1010   std::vector<DWARFDie> Worklist;
1011   Worklist.push_back(Result.FunctionDIE);
1012   while (!Worklist.empty()) {
1013     DWARFDie DIE = Worklist.back();
1014     Worklist.pop_back();
1015 
1016     if (!DIE.isValid())
1017       continue;
1018 
1019     if (DIE.getTag() == DW_TAG_lexical_block &&
1020         DIE.addressRangeContainsAddress(Address)) {
1021       Result.BlockDIE = DIE;
1022       break;
1023     }
1024 
1025     append_range(Worklist, DIE);
1026   }
1027 
1028   return Result;
1029 }
1030 
1031 /// TODO: change input parameter from "uint64_t Address"
1032 ///       into "SectionedAddress Address"
1033 static bool getFunctionNameAndStartLineForAddress(DWARFCompileUnit *CU,
1034                                                   uint64_t Address,
1035                                                   FunctionNameKind Kind,
1036                                                   DILineInfoSpecifier::FileLineInfoKind FileNameKind,
1037                                                   std::string &FunctionName,
1038                                                   std::string &StartFile,
1039                                                   uint32_t &StartLine) {
1040   // The address may correspond to instruction in some inlined function,
1041   // so we have to build the chain of inlined functions and take the
1042   // name of the topmost function in it.
1043   SmallVector<DWARFDie, 4> InlinedChain;
1044   CU->getInlinedChainForAddress(Address, InlinedChain);
1045   if (InlinedChain.empty())
1046     return false;
1047 
1048   const DWARFDie &DIE = InlinedChain[0];
1049   bool FoundResult = false;
1050   const char *Name = nullptr;
1051   if (Kind != FunctionNameKind::None && (Name = DIE.getSubroutineName(Kind))) {
1052     FunctionName = Name;
1053     FoundResult = true;
1054   }
1055   std::string DeclFile = DIE.getDeclFile(FileNameKind);
1056   if (!DeclFile.empty()) {
1057     StartFile = DeclFile;
1058     FoundResult = true;
1059   }
1060   if (auto DeclLineResult = DIE.getDeclLine()) {
1061     StartLine = DeclLineResult;
1062     FoundResult = true;
1063   }
1064 
1065   return FoundResult;
1066 }
1067 
1068 static Optional<uint64_t> getTypeSize(DWARFDie Type, uint64_t PointerSize) {
1069   if (auto SizeAttr = Type.find(DW_AT_byte_size))
1070     if (Optional<uint64_t> Size = SizeAttr->getAsUnsignedConstant())
1071       return Size;
1072 
1073   switch (Type.getTag()) {
1074   case DW_TAG_pointer_type:
1075   case DW_TAG_reference_type:
1076   case DW_TAG_rvalue_reference_type:
1077     return PointerSize;
1078   case DW_TAG_ptr_to_member_type: {
1079     if (DWARFDie BaseType = Type.getAttributeValueAsReferencedDie(DW_AT_type))
1080       if (BaseType.getTag() == DW_TAG_subroutine_type)
1081         return 2 * PointerSize;
1082     return PointerSize;
1083   }
1084   case DW_TAG_const_type:
1085   case DW_TAG_volatile_type:
1086   case DW_TAG_restrict_type:
1087   case DW_TAG_typedef: {
1088     if (DWARFDie BaseType = Type.getAttributeValueAsReferencedDie(DW_AT_type))
1089       return getTypeSize(BaseType, PointerSize);
1090     break;
1091   }
1092   case DW_TAG_array_type: {
1093     DWARFDie BaseType = Type.getAttributeValueAsReferencedDie(DW_AT_type);
1094     if (!BaseType)
1095       return Optional<uint64_t>();
1096     Optional<uint64_t> BaseSize = getTypeSize(BaseType, PointerSize);
1097     if (!BaseSize)
1098       return Optional<uint64_t>();
1099     uint64_t Size = *BaseSize;
1100     for (DWARFDie Child : Type) {
1101       if (Child.getTag() != DW_TAG_subrange_type)
1102         continue;
1103 
1104       if (auto ElemCountAttr = Child.find(DW_AT_count))
1105         if (Optional<uint64_t> ElemCount =
1106                 ElemCountAttr->getAsUnsignedConstant())
1107           Size *= *ElemCount;
1108       if (auto UpperBoundAttr = Child.find(DW_AT_upper_bound))
1109         if (Optional<int64_t> UpperBound =
1110                 UpperBoundAttr->getAsSignedConstant()) {
1111           int64_t LowerBound = 0;
1112           if (auto LowerBoundAttr = Child.find(DW_AT_lower_bound))
1113             LowerBound = LowerBoundAttr->getAsSignedConstant().getValueOr(0);
1114           Size *= *UpperBound - LowerBound + 1;
1115         }
1116     }
1117     return Size;
1118   }
1119   default:
1120     break;
1121   }
1122   return Optional<uint64_t>();
1123 }
1124 
1125 static Optional<int64_t>
1126 getExpressionFrameOffset(ArrayRef<uint8_t> Expr,
1127                          Optional<unsigned> FrameBaseReg) {
1128   if (!Expr.empty() &&
1129       (Expr[0] == DW_OP_fbreg ||
1130        (FrameBaseReg && Expr[0] == DW_OP_breg0 + *FrameBaseReg))) {
1131     unsigned Count;
1132     int64_t Offset = decodeSLEB128(Expr.data() + 1, &Count, Expr.end());
1133     // A single DW_OP_fbreg or DW_OP_breg.
1134     if (Expr.size() == Count + 1)
1135       return Offset;
1136     // Same + DW_OP_deref (Fortran arrays look like this).
1137     if (Expr.size() == Count + 2 && Expr[Count + 1] == DW_OP_deref)
1138       return Offset;
1139     // Fallthrough. Do not accept ex. (DW_OP_breg W29, DW_OP_stack_value)
1140   }
1141   return None;
1142 }
1143 
1144 void DWARFContext::addLocalsForDie(DWARFCompileUnit *CU, DWARFDie Subprogram,
1145                                    DWARFDie Die, std::vector<DILocal> &Result) {
1146   if (Die.getTag() == DW_TAG_variable ||
1147       Die.getTag() == DW_TAG_formal_parameter) {
1148     DILocal Local;
1149     if (const char *Name = Subprogram.getSubroutineName(DINameKind::ShortName))
1150       Local.FunctionName = Name;
1151 
1152     Optional<unsigned> FrameBaseReg;
1153     if (auto FrameBase = Subprogram.find(DW_AT_frame_base))
1154       if (Optional<ArrayRef<uint8_t>> Expr = FrameBase->getAsBlock())
1155         if (!Expr->empty() && (*Expr)[0] >= DW_OP_reg0 &&
1156             (*Expr)[0] <= DW_OP_reg31) {
1157           FrameBaseReg = (*Expr)[0] - DW_OP_reg0;
1158         }
1159 
1160     if (Expected<std::vector<DWARFLocationExpression>> Loc =
1161             Die.getLocations(DW_AT_location)) {
1162       for (const auto &Entry : *Loc) {
1163         if (Optional<int64_t> FrameOffset =
1164                 getExpressionFrameOffset(Entry.Expr, FrameBaseReg)) {
1165           Local.FrameOffset = *FrameOffset;
1166           break;
1167         }
1168       }
1169     } else {
1170       // FIXME: missing DW_AT_location is OK here, but other errors should be
1171       // reported to the user.
1172       consumeError(Loc.takeError());
1173     }
1174 
1175     if (auto TagOffsetAttr = Die.find(DW_AT_LLVM_tag_offset))
1176       Local.TagOffset = TagOffsetAttr->getAsUnsignedConstant();
1177 
1178     if (auto Origin =
1179             Die.getAttributeValueAsReferencedDie(DW_AT_abstract_origin))
1180       Die = Origin;
1181     if (auto NameAttr = Die.find(DW_AT_name))
1182       if (Optional<const char *> Name = NameAttr->getAsCString())
1183         Local.Name = *Name;
1184     if (auto Type = Die.getAttributeValueAsReferencedDie(DW_AT_type))
1185       Local.Size = getTypeSize(Type, getCUAddrSize());
1186     if (auto DeclFileAttr = Die.find(DW_AT_decl_file)) {
1187       if (const auto *LT = CU->getContext().getLineTableForUnit(CU))
1188         LT->getFileNameByIndex(
1189             DeclFileAttr->getAsUnsignedConstant().getValue(),
1190             CU->getCompilationDir(),
1191             DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath,
1192             Local.DeclFile);
1193     }
1194     if (auto DeclLineAttr = Die.find(DW_AT_decl_line))
1195       Local.DeclLine = DeclLineAttr->getAsUnsignedConstant().getValue();
1196 
1197     Result.push_back(Local);
1198     return;
1199   }
1200 
1201   if (Die.getTag() == DW_TAG_inlined_subroutine)
1202     if (auto Origin =
1203             Die.getAttributeValueAsReferencedDie(DW_AT_abstract_origin))
1204       Subprogram = Origin;
1205 
1206   for (auto Child : Die)
1207     addLocalsForDie(CU, Subprogram, Child, Result);
1208 }
1209 
1210 std::vector<DILocal>
1211 DWARFContext::getLocalsForAddress(object::SectionedAddress Address) {
1212   std::vector<DILocal> Result;
1213   DWARFCompileUnit *CU = getCompileUnitForAddress(Address.Address);
1214   if (!CU)
1215     return Result;
1216 
1217   DWARFDie Subprogram = CU->getSubroutineForAddress(Address.Address);
1218   if (Subprogram.isValid())
1219     addLocalsForDie(CU, Subprogram, Subprogram, Result);
1220   return Result;
1221 }
1222 
1223 DILineInfo DWARFContext::getLineInfoForAddress(object::SectionedAddress Address,
1224                                                DILineInfoSpecifier Spec) {
1225   DILineInfo Result;
1226 
1227   DWARFCompileUnit *CU = getCompileUnitForAddress(Address.Address);
1228   if (!CU)
1229     return Result;
1230 
1231   getFunctionNameAndStartLineForAddress(CU, Address.Address, Spec.FNKind, Spec.FLIKind,
1232                                         Result.FunctionName,
1233                                         Result.StartFileName, Result.StartLine);
1234   if (Spec.FLIKind != FileLineInfoKind::None) {
1235     if (const DWARFLineTable *LineTable = getLineTableForUnit(CU)) {
1236       LineTable->getFileLineInfoForAddress(
1237           {Address.Address, Address.SectionIndex}, CU->getCompilationDir(),
1238           Spec.FLIKind, Result);
1239     }
1240   }
1241   return Result;
1242 }
1243 
1244 DILineInfoTable DWARFContext::getLineInfoForAddressRange(
1245     object::SectionedAddress Address, uint64_t Size, DILineInfoSpecifier Spec) {
1246   DILineInfoTable  Lines;
1247   DWARFCompileUnit *CU = getCompileUnitForAddress(Address.Address);
1248   if (!CU)
1249     return Lines;
1250 
1251   uint32_t StartLine = 0;
1252   std::string StartFileName;
1253   std::string FunctionName(DILineInfo::BadString);
1254   getFunctionNameAndStartLineForAddress(CU, Address.Address, Spec.FNKind, Spec.FLIKind,
1255                                         FunctionName, StartFileName, StartLine);
1256 
1257   // If the Specifier says we don't need FileLineInfo, just
1258   // return the top-most function at the starting address.
1259   if (Spec.FLIKind == FileLineInfoKind::None) {
1260     DILineInfo Result;
1261     Result.FunctionName = FunctionName;
1262     Result.StartFileName = StartFileName;
1263     Result.StartLine = StartLine;
1264     Lines.push_back(std::make_pair(Address.Address, Result));
1265     return Lines;
1266   }
1267 
1268   const DWARFLineTable *LineTable = getLineTableForUnit(CU);
1269 
1270   // Get the index of row we're looking for in the line table.
1271   std::vector<uint32_t> RowVector;
1272   if (!LineTable->lookupAddressRange({Address.Address, Address.SectionIndex},
1273                                      Size, RowVector)) {
1274     return Lines;
1275   }
1276 
1277   for (uint32_t RowIndex : RowVector) {
1278     // Take file number and line/column from the row.
1279     const DWARFDebugLine::Row &Row = LineTable->Rows[RowIndex];
1280     DILineInfo Result;
1281     LineTable->getFileNameByIndex(Row.File, CU->getCompilationDir(),
1282                                   Spec.FLIKind, Result.FileName);
1283     Result.FunctionName = FunctionName;
1284     Result.Line = Row.Line;
1285     Result.Column = Row.Column;
1286     Result.StartFileName = StartFileName;
1287     Result.StartLine = StartLine;
1288     Lines.push_back(std::make_pair(Row.Address.Address, Result));
1289   }
1290 
1291   return Lines;
1292 }
1293 
1294 DIInliningInfo
1295 DWARFContext::getInliningInfoForAddress(object::SectionedAddress Address,
1296                                         DILineInfoSpecifier Spec) {
1297   DIInliningInfo InliningInfo;
1298 
1299   DWARFCompileUnit *CU = getCompileUnitForAddress(Address.Address);
1300   if (!CU)
1301     return InliningInfo;
1302 
1303   const DWARFLineTable *LineTable = nullptr;
1304   SmallVector<DWARFDie, 4> InlinedChain;
1305   CU->getInlinedChainForAddress(Address.Address, InlinedChain);
1306   if (InlinedChain.size() == 0) {
1307     // If there is no DIE for address (e.g. it is in unavailable .dwo file),
1308     // try to at least get file/line info from symbol table.
1309     if (Spec.FLIKind != FileLineInfoKind::None) {
1310       DILineInfo Frame;
1311       LineTable = getLineTableForUnit(CU);
1312       if (LineTable && LineTable->getFileLineInfoForAddress(
1313                            {Address.Address, Address.SectionIndex},
1314                            CU->getCompilationDir(), Spec.FLIKind, Frame))
1315         InliningInfo.addFrame(Frame);
1316     }
1317     return InliningInfo;
1318   }
1319 
1320   uint32_t CallFile = 0, CallLine = 0, CallColumn = 0, CallDiscriminator = 0;
1321   for (uint32_t i = 0, n = InlinedChain.size(); i != n; i++) {
1322     DWARFDie &FunctionDIE = InlinedChain[i];
1323     DILineInfo Frame;
1324     // Get function name if necessary.
1325     if (const char *Name = FunctionDIE.getSubroutineName(Spec.FNKind))
1326       Frame.FunctionName = Name;
1327     if (auto DeclLineResult = FunctionDIE.getDeclLine())
1328       Frame.StartLine = DeclLineResult;
1329     Frame.StartFileName = FunctionDIE.getDeclFile(Spec.FLIKind);
1330     if (Spec.FLIKind != FileLineInfoKind::None) {
1331       if (i == 0) {
1332         // For the topmost frame, initialize the line table of this
1333         // compile unit and fetch file/line info from it.
1334         LineTable = getLineTableForUnit(CU);
1335         // For the topmost routine, get file/line info from line table.
1336         if (LineTable)
1337           LineTable->getFileLineInfoForAddress(
1338               {Address.Address, Address.SectionIndex}, CU->getCompilationDir(),
1339               Spec.FLIKind, Frame);
1340       } else {
1341         // Otherwise, use call file, call line and call column from
1342         // previous DIE in inlined chain.
1343         if (LineTable)
1344           LineTable->getFileNameByIndex(CallFile, CU->getCompilationDir(),
1345                                         Spec.FLIKind, Frame.FileName);
1346         Frame.Line = CallLine;
1347         Frame.Column = CallColumn;
1348         Frame.Discriminator = CallDiscriminator;
1349       }
1350       // Get call file/line/column of a current DIE.
1351       if (i + 1 < n) {
1352         FunctionDIE.getCallerFrame(CallFile, CallLine, CallColumn,
1353                                    CallDiscriminator);
1354       }
1355     }
1356     InliningInfo.addFrame(Frame);
1357   }
1358   return InliningInfo;
1359 }
1360 
1361 std::shared_ptr<DWARFContext>
1362 DWARFContext::getDWOContext(StringRef AbsolutePath) {
1363   if (auto S = DWP.lock()) {
1364     DWARFContext *Ctxt = S->Context.get();
1365     return std::shared_ptr<DWARFContext>(std::move(S), Ctxt);
1366   }
1367 
1368   std::weak_ptr<DWOFile> *Entry = &DWOFiles[AbsolutePath];
1369 
1370   if (auto S = Entry->lock()) {
1371     DWARFContext *Ctxt = S->Context.get();
1372     return std::shared_ptr<DWARFContext>(std::move(S), Ctxt);
1373   }
1374 
1375   Expected<OwningBinary<ObjectFile>> Obj = [&] {
1376     if (!CheckedForDWP) {
1377       SmallString<128> DWPName;
1378       auto Obj = object::ObjectFile::createObjectFile(
1379           this->DWPName.empty()
1380               ? (DObj->getFileName() + ".dwp").toStringRef(DWPName)
1381               : StringRef(this->DWPName));
1382       if (Obj) {
1383         Entry = &DWP;
1384         return Obj;
1385       } else {
1386         CheckedForDWP = true;
1387         // TODO: Should this error be handled (maybe in a high verbosity mode)
1388         // before falling back to .dwo files?
1389         consumeError(Obj.takeError());
1390       }
1391     }
1392 
1393     return object::ObjectFile::createObjectFile(AbsolutePath);
1394   }();
1395 
1396   if (!Obj) {
1397     // TODO: Actually report errors helpfully.
1398     consumeError(Obj.takeError());
1399     return nullptr;
1400   }
1401 
1402   auto S = std::make_shared<DWOFile>();
1403   S->File = std::move(Obj.get());
1404   S->Context = DWARFContext::create(*S->File.getBinary());
1405   *Entry = S;
1406   auto *Ctxt = S->Context.get();
1407   return std::shared_ptr<DWARFContext>(std::move(S), Ctxt);
1408 }
1409 
1410 static Error createError(const Twine &Reason, llvm::Error E) {
1411   return make_error<StringError>(Reason + toString(std::move(E)),
1412                                  inconvertibleErrorCode());
1413 }
1414 
1415 /// SymInfo contains information about symbol: it's address
1416 /// and section index which is -1LL for absolute symbols.
1417 struct SymInfo {
1418   uint64_t Address;
1419   uint64_t SectionIndex;
1420 };
1421 
1422 /// Returns the address of symbol relocation used against and a section index.
1423 /// Used for futher relocations computation. Symbol's section load address is
1424 static Expected<SymInfo> getSymbolInfo(const object::ObjectFile &Obj,
1425                                        const RelocationRef &Reloc,
1426                                        const LoadedObjectInfo *L,
1427                                        std::map<SymbolRef, SymInfo> &Cache) {
1428   SymInfo Ret = {0, (uint64_t)-1LL};
1429   object::section_iterator RSec = Obj.section_end();
1430   object::symbol_iterator Sym = Reloc.getSymbol();
1431 
1432   std::map<SymbolRef, SymInfo>::iterator CacheIt = Cache.end();
1433   // First calculate the address of the symbol or section as it appears
1434   // in the object file
1435   if (Sym != Obj.symbol_end()) {
1436     bool New;
1437     std::tie(CacheIt, New) = Cache.insert({*Sym, {0, 0}});
1438     if (!New)
1439       return CacheIt->second;
1440 
1441     Expected<uint64_t> SymAddrOrErr = Sym->getAddress();
1442     if (!SymAddrOrErr)
1443       return createError("failed to compute symbol address: ",
1444                          SymAddrOrErr.takeError());
1445 
1446     // Also remember what section this symbol is in for later
1447     auto SectOrErr = Sym->getSection();
1448     if (!SectOrErr)
1449       return createError("failed to get symbol section: ",
1450                          SectOrErr.takeError());
1451 
1452     RSec = *SectOrErr;
1453     Ret.Address = *SymAddrOrErr;
1454   } else if (auto *MObj = dyn_cast<MachOObjectFile>(&Obj)) {
1455     RSec = MObj->getRelocationSection(Reloc.getRawDataRefImpl());
1456     Ret.Address = RSec->getAddress();
1457   }
1458 
1459   if (RSec != Obj.section_end())
1460     Ret.SectionIndex = RSec->getIndex();
1461 
1462   // If we are given load addresses for the sections, we need to adjust:
1463   // SymAddr = (Address of Symbol Or Section in File) -
1464   //           (Address of Section in File) +
1465   //           (Load Address of Section)
1466   // RSec is now either the section being targeted or the section
1467   // containing the symbol being targeted. In either case,
1468   // we need to perform the same computation.
1469   if (L && RSec != Obj.section_end())
1470     if (uint64_t SectionLoadAddress = L->getSectionLoadAddress(*RSec))
1471       Ret.Address += SectionLoadAddress - RSec->getAddress();
1472 
1473   if (CacheIt != Cache.end())
1474     CacheIt->second = Ret;
1475 
1476   return Ret;
1477 }
1478 
1479 static bool isRelocScattered(const object::ObjectFile &Obj,
1480                              const RelocationRef &Reloc) {
1481   const MachOObjectFile *MachObj = dyn_cast<MachOObjectFile>(&Obj);
1482   if (!MachObj)
1483     return false;
1484   // MachO also has relocations that point to sections and
1485   // scattered relocations.
1486   auto RelocInfo = MachObj->getRelocation(Reloc.getRawDataRefImpl());
1487   return MachObj->isRelocationScattered(RelocInfo);
1488 }
1489 
1490 namespace {
1491 struct DWARFSectionMap final : public DWARFSection {
1492   RelocAddrMap Relocs;
1493 };
1494 
1495 class DWARFObjInMemory final : public DWARFObject {
1496   bool IsLittleEndian;
1497   uint8_t AddressSize;
1498   StringRef FileName;
1499   const object::ObjectFile *Obj = nullptr;
1500   std::vector<SectionName> SectionNames;
1501 
1502   using InfoSectionMap = MapVector<object::SectionRef, DWARFSectionMap,
1503                                    std::map<object::SectionRef, unsigned>>;
1504 
1505   InfoSectionMap InfoSections;
1506   InfoSectionMap TypesSections;
1507   InfoSectionMap InfoDWOSections;
1508   InfoSectionMap TypesDWOSections;
1509 
1510   DWARFSectionMap LocSection;
1511   DWARFSectionMap LoclistsSection;
1512   DWARFSectionMap LoclistsDWOSection;
1513   DWARFSectionMap LineSection;
1514   DWARFSectionMap RangesSection;
1515   DWARFSectionMap RnglistsSection;
1516   DWARFSectionMap StrOffsetsSection;
1517   DWARFSectionMap LineDWOSection;
1518   DWARFSectionMap FrameSection;
1519   DWARFSectionMap EHFrameSection;
1520   DWARFSectionMap LocDWOSection;
1521   DWARFSectionMap StrOffsetsDWOSection;
1522   DWARFSectionMap RangesDWOSection;
1523   DWARFSectionMap RnglistsDWOSection;
1524   DWARFSectionMap AddrSection;
1525   DWARFSectionMap AppleNamesSection;
1526   DWARFSectionMap AppleTypesSection;
1527   DWARFSectionMap AppleNamespacesSection;
1528   DWARFSectionMap AppleObjCSection;
1529   DWARFSectionMap NamesSection;
1530   DWARFSectionMap PubnamesSection;
1531   DWARFSectionMap PubtypesSection;
1532   DWARFSectionMap GnuPubnamesSection;
1533   DWARFSectionMap GnuPubtypesSection;
1534   DWARFSectionMap MacroSection;
1535 
1536   DWARFSectionMap *mapNameToDWARFSection(StringRef Name) {
1537     return StringSwitch<DWARFSectionMap *>(Name)
1538         .Case("debug_loc", &LocSection)
1539         .Case("debug_loclists", &LoclistsSection)
1540         .Case("debug_loclists.dwo", &LoclistsDWOSection)
1541         .Case("debug_line", &LineSection)
1542         .Case("debug_frame", &FrameSection)
1543         .Case("eh_frame", &EHFrameSection)
1544         .Case("debug_str_offsets", &StrOffsetsSection)
1545         .Case("debug_ranges", &RangesSection)
1546         .Case("debug_rnglists", &RnglistsSection)
1547         .Case("debug_loc.dwo", &LocDWOSection)
1548         .Case("debug_line.dwo", &LineDWOSection)
1549         .Case("debug_names", &NamesSection)
1550         .Case("debug_rnglists.dwo", &RnglistsDWOSection)
1551         .Case("debug_str_offsets.dwo", &StrOffsetsDWOSection)
1552         .Case("debug_addr", &AddrSection)
1553         .Case("apple_names", &AppleNamesSection)
1554         .Case("debug_pubnames", &PubnamesSection)
1555         .Case("debug_pubtypes", &PubtypesSection)
1556         .Case("debug_gnu_pubnames", &GnuPubnamesSection)
1557         .Case("debug_gnu_pubtypes", &GnuPubtypesSection)
1558         .Case("apple_types", &AppleTypesSection)
1559         .Case("apple_namespaces", &AppleNamespacesSection)
1560         .Case("apple_namespac", &AppleNamespacesSection)
1561         .Case("apple_objc", &AppleObjCSection)
1562         .Case("debug_macro", &MacroSection)
1563         .Default(nullptr);
1564   }
1565 
1566   StringRef AbbrevSection;
1567   StringRef ArangesSection;
1568   StringRef StrSection;
1569   StringRef MacinfoSection;
1570   StringRef MacinfoDWOSection;
1571   StringRef MacroDWOSection;
1572   StringRef AbbrevDWOSection;
1573   StringRef StrDWOSection;
1574   StringRef CUIndexSection;
1575   StringRef GdbIndexSection;
1576   StringRef TUIndexSection;
1577   StringRef LineStrSection;
1578 
1579   // A deque holding section data whose iterators are not invalidated when
1580   // new decompressed sections are inserted at the end.
1581   std::deque<SmallString<0>> UncompressedSections;
1582 
1583   StringRef *mapSectionToMember(StringRef Name) {
1584     if (DWARFSection *Sec = mapNameToDWARFSection(Name))
1585       return &Sec->Data;
1586     return StringSwitch<StringRef *>(Name)
1587         .Case("debug_abbrev", &AbbrevSection)
1588         .Case("debug_aranges", &ArangesSection)
1589         .Case("debug_str", &StrSection)
1590         .Case("debug_macinfo", &MacinfoSection)
1591         .Case("debug_macinfo.dwo", &MacinfoDWOSection)
1592         .Case("debug_macro.dwo", &MacroDWOSection)
1593         .Case("debug_abbrev.dwo", &AbbrevDWOSection)
1594         .Case("debug_str.dwo", &StrDWOSection)
1595         .Case("debug_cu_index", &CUIndexSection)
1596         .Case("debug_tu_index", &TUIndexSection)
1597         .Case("gdb_index", &GdbIndexSection)
1598         .Case("debug_line_str", &LineStrSection)
1599         // Any more debug info sections go here.
1600         .Default(nullptr);
1601   }
1602 
1603   /// If Sec is compressed section, decompresses and updates its contents
1604   /// provided by Data. Otherwise leaves it unchanged.
1605   Error maybeDecompress(const object::SectionRef &Sec, StringRef Name,
1606                         StringRef &Data) {
1607     if (!Decompressor::isCompressed(Sec))
1608       return Error::success();
1609 
1610     Expected<Decompressor> Decompressor =
1611         Decompressor::create(Name, Data, IsLittleEndian, AddressSize == 8);
1612     if (!Decompressor)
1613       return Decompressor.takeError();
1614 
1615     SmallString<0> Out;
1616     if (auto Err = Decompressor->resizeAndDecompress(Out))
1617       return Err;
1618 
1619     UncompressedSections.push_back(std::move(Out));
1620     Data = UncompressedSections.back();
1621 
1622     return Error::success();
1623   }
1624 
1625 public:
1626   DWARFObjInMemory(const StringMap<std::unique_ptr<MemoryBuffer>> &Sections,
1627                    uint8_t AddrSize, bool IsLittleEndian)
1628       : IsLittleEndian(IsLittleEndian) {
1629     for (const auto &SecIt : Sections) {
1630       if (StringRef *SectionData = mapSectionToMember(SecIt.first()))
1631         *SectionData = SecIt.second->getBuffer();
1632       else if (SecIt.first() == "debug_info")
1633         // Find debug_info and debug_types data by section rather than name as
1634         // there are multiple, comdat grouped, of these sections.
1635         InfoSections[SectionRef()].Data = SecIt.second->getBuffer();
1636       else if (SecIt.first() == "debug_info.dwo")
1637         InfoDWOSections[SectionRef()].Data = SecIt.second->getBuffer();
1638       else if (SecIt.first() == "debug_types")
1639         TypesSections[SectionRef()].Data = SecIt.second->getBuffer();
1640       else if (SecIt.first() == "debug_types.dwo")
1641         TypesDWOSections[SectionRef()].Data = SecIt.second->getBuffer();
1642     }
1643   }
1644   DWARFObjInMemory(const object::ObjectFile &Obj, const LoadedObjectInfo *L,
1645                    function_ref<void(Error)> HandleError, function_ref<void(Error)> HandleWarning )
1646       : IsLittleEndian(Obj.isLittleEndian()),
1647         AddressSize(Obj.getBytesInAddress()), FileName(Obj.getFileName()),
1648         Obj(&Obj) {
1649 
1650     StringMap<unsigned> SectionAmountMap;
1651     for (const SectionRef &Section : Obj.sections()) {
1652       StringRef Name;
1653       if (auto NameOrErr = Section.getName())
1654         Name = *NameOrErr;
1655       else
1656         consumeError(NameOrErr.takeError());
1657 
1658       ++SectionAmountMap[Name];
1659       SectionNames.push_back({ Name, true });
1660 
1661       // Skip BSS and Virtual sections, they aren't interesting.
1662       if (Section.isBSS() || Section.isVirtual())
1663         continue;
1664 
1665       // Skip sections stripped by dsymutil.
1666       if (Section.isStripped())
1667         continue;
1668 
1669       StringRef Data;
1670       Expected<section_iterator> SecOrErr = Section.getRelocatedSection();
1671       if (!SecOrErr) {
1672         HandleError(createError("failed to get relocated section: ",
1673                                 SecOrErr.takeError()));
1674         continue;
1675       }
1676 
1677       // Try to obtain an already relocated version of this section.
1678       // Else use the unrelocated section from the object file. We'll have to
1679       // apply relocations ourselves later.
1680       section_iterator RelocatedSection = *SecOrErr;
1681       if (!L || !L->getLoadedSectionContents(*RelocatedSection, Data)) {
1682         Expected<StringRef> E = Section.getContents();
1683         if (E)
1684           Data = *E;
1685         else
1686           // maybeDecompress below will error.
1687           consumeError(E.takeError());
1688       }
1689 
1690       if (auto Err = maybeDecompress(Section, Name, Data)) {
1691         HandleError(createError("failed to decompress '" + Name + "', ",
1692                                 std::move(Err)));
1693         continue;
1694       }
1695 
1696       // Compressed sections names in GNU style starts from ".z",
1697       // at this point section is decompressed and we drop compression prefix.
1698       Name = Name.substr(
1699           Name.find_first_not_of("._z")); // Skip ".", "z" and "_" prefixes.
1700 
1701       // Map platform specific debug section names to DWARF standard section
1702       // names.
1703       Name = Obj.mapDebugSectionName(Name);
1704 
1705       if (StringRef *SectionData = mapSectionToMember(Name)) {
1706         *SectionData = Data;
1707         if (Name == "debug_ranges") {
1708           // FIXME: Use the other dwo range section when we emit it.
1709           RangesDWOSection.Data = Data;
1710         }
1711       } else if (InfoSectionMap *Sections =
1712                      StringSwitch<InfoSectionMap *>(Name)
1713                          .Case("debug_info", &InfoSections)
1714                          .Case("debug_info.dwo", &InfoDWOSections)
1715                          .Case("debug_types", &TypesSections)
1716                          .Case("debug_types.dwo", &TypesDWOSections)
1717                          .Default(nullptr)) {
1718         // Find debug_info and debug_types data by section rather than name as
1719         // there are multiple, comdat grouped, of these sections.
1720         DWARFSectionMap &S = (*Sections)[Section];
1721         S.Data = Data;
1722       }
1723 
1724       if (RelocatedSection == Obj.section_end())
1725         continue;
1726 
1727       StringRef RelSecName;
1728       if (auto NameOrErr = RelocatedSection->getName())
1729         RelSecName = *NameOrErr;
1730       else
1731         consumeError(NameOrErr.takeError());
1732 
1733       // If the section we're relocating was relocated already by the JIT,
1734       // then we used the relocated version above, so we do not need to process
1735       // relocations for it now.
1736       StringRef RelSecData;
1737       if (L && L->getLoadedSectionContents(*RelocatedSection, RelSecData))
1738         continue;
1739 
1740       // In Mach-o files, the relocations do not need to be applied if
1741       // there is no load offset to apply. The value read at the
1742       // relocation point already factors in the section address
1743       // (actually applying the relocations will produce wrong results
1744       // as the section address will be added twice).
1745       if (!L && isa<MachOObjectFile>(&Obj))
1746         continue;
1747 
1748       RelSecName = RelSecName.substr(
1749           RelSecName.find_first_not_of("._z")); // Skip . and _ prefixes.
1750 
1751       // TODO: Add support for relocations in other sections as needed.
1752       // Record relocations for the debug_info and debug_line sections.
1753       DWARFSectionMap *Sec = mapNameToDWARFSection(RelSecName);
1754       RelocAddrMap *Map = Sec ? &Sec->Relocs : nullptr;
1755       if (!Map) {
1756         // Find debug_info and debug_types relocs by section rather than name
1757         // as there are multiple, comdat grouped, of these sections.
1758         if (RelSecName == "debug_info")
1759           Map = &static_cast<DWARFSectionMap &>(InfoSections[*RelocatedSection])
1760                      .Relocs;
1761         else if (RelSecName == "debug_info.dwo")
1762           Map = &static_cast<DWARFSectionMap &>(
1763                      InfoDWOSections[*RelocatedSection])
1764                      .Relocs;
1765         else if (RelSecName == "debug_types")
1766           Map =
1767               &static_cast<DWARFSectionMap &>(TypesSections[*RelocatedSection])
1768                    .Relocs;
1769         else if (RelSecName == "debug_types.dwo")
1770           Map = &static_cast<DWARFSectionMap &>(
1771                      TypesDWOSections[*RelocatedSection])
1772                      .Relocs;
1773         else
1774           continue;
1775       }
1776 
1777       if (Section.relocation_begin() == Section.relocation_end())
1778         continue;
1779 
1780       // Symbol to [address, section index] cache mapping.
1781       std::map<SymbolRef, SymInfo> AddrCache;
1782       SupportsRelocation Supports;
1783       RelocationResolver Resolver;
1784       std::tie(Supports, Resolver) = getRelocationResolver(Obj);
1785       for (const RelocationRef &Reloc : Section.relocations()) {
1786         // FIXME: it's not clear how to correctly handle scattered
1787         // relocations.
1788         if (isRelocScattered(Obj, Reloc))
1789           continue;
1790 
1791         Expected<SymInfo> SymInfoOrErr =
1792             getSymbolInfo(Obj, Reloc, L, AddrCache);
1793         if (!SymInfoOrErr) {
1794           HandleError(SymInfoOrErr.takeError());
1795           continue;
1796         }
1797 
1798         // Check if Resolver can handle this relocation type early so as not to
1799         // handle invalid cases in DWARFDataExtractor.
1800         //
1801         // TODO Don't store Resolver in every RelocAddrEntry.
1802         if (Supports && Supports(Reloc.getType())) {
1803           auto I = Map->try_emplace(
1804               Reloc.getOffset(),
1805               RelocAddrEntry{SymInfoOrErr->SectionIndex, Reloc,
1806                              SymInfoOrErr->Address,
1807                              Optional<object::RelocationRef>(), 0, Resolver});
1808           // If we didn't successfully insert that's because we already had a
1809           // relocation for that offset. Store it as a second relocation in the
1810           // same RelocAddrEntry instead.
1811           if (!I.second) {
1812             RelocAddrEntry &entry = I.first->getSecond();
1813             if (entry.Reloc2) {
1814               HandleError(createError(
1815                   "At most two relocations per offset are supported"));
1816             }
1817             entry.Reloc2 = Reloc;
1818             entry.SymbolValue2 = SymInfoOrErr->Address;
1819           }
1820         } else {
1821           SmallString<32> Type;
1822           Reloc.getTypeName(Type);
1823           // FIXME: Support more relocations & change this to an error
1824           HandleWarning(
1825               createError("failed to compute relocation: " + Type + ", ",
1826                           errorCodeToError(object_error::parse_failed)));
1827         }
1828       }
1829     }
1830 
1831     for (SectionName &S : SectionNames)
1832       if (SectionAmountMap[S.Name] > 1)
1833         S.IsNameUnique = false;
1834   }
1835 
1836   Optional<RelocAddrEntry> find(const DWARFSection &S,
1837                                 uint64_t Pos) const override {
1838     auto &Sec = static_cast<const DWARFSectionMap &>(S);
1839     RelocAddrMap::const_iterator AI = Sec.Relocs.find(Pos);
1840     if (AI == Sec.Relocs.end())
1841       return None;
1842     return AI->second;
1843   }
1844 
1845   const object::ObjectFile *getFile() const override { return Obj; }
1846 
1847   ArrayRef<SectionName> getSectionNames() const override {
1848     return SectionNames;
1849   }
1850 
1851   bool isLittleEndian() const override { return IsLittleEndian; }
1852   StringRef getAbbrevDWOSection() const override { return AbbrevDWOSection; }
1853   const DWARFSection &getLineDWOSection() const override {
1854     return LineDWOSection;
1855   }
1856   const DWARFSection &getLocDWOSection() const override {
1857     return LocDWOSection;
1858   }
1859   StringRef getStrDWOSection() const override { return StrDWOSection; }
1860   const DWARFSection &getStrOffsetsDWOSection() const override {
1861     return StrOffsetsDWOSection;
1862   }
1863   const DWARFSection &getRangesDWOSection() const override {
1864     return RangesDWOSection;
1865   }
1866   const DWARFSection &getRnglistsDWOSection() const override {
1867     return RnglistsDWOSection;
1868   }
1869   const DWARFSection &getLoclistsDWOSection() const override {
1870     return LoclistsDWOSection;
1871   }
1872   const DWARFSection &getAddrSection() const override { return AddrSection; }
1873   StringRef getCUIndexSection() const override { return CUIndexSection; }
1874   StringRef getGdbIndexSection() const override { return GdbIndexSection; }
1875   StringRef getTUIndexSection() const override { return TUIndexSection; }
1876 
1877   // DWARF v5
1878   const DWARFSection &getStrOffsetsSection() const override {
1879     return StrOffsetsSection;
1880   }
1881   StringRef getLineStrSection() const override { return LineStrSection; }
1882 
1883   // Sections for DWARF5 split dwarf proposal.
1884   void forEachInfoDWOSections(
1885       function_ref<void(const DWARFSection &)> F) const override {
1886     for (auto &P : InfoDWOSections)
1887       F(P.second);
1888   }
1889   void forEachTypesDWOSections(
1890       function_ref<void(const DWARFSection &)> F) const override {
1891     for (auto &P : TypesDWOSections)
1892       F(P.second);
1893   }
1894 
1895   StringRef getAbbrevSection() const override { return AbbrevSection; }
1896   const DWARFSection &getLocSection() const override { return LocSection; }
1897   const DWARFSection &getLoclistsSection() const override { return LoclistsSection; }
1898   StringRef getArangesSection() const override { return ArangesSection; }
1899   const DWARFSection &getFrameSection() const override {
1900     return FrameSection;
1901   }
1902   const DWARFSection &getEHFrameSection() const override {
1903     return EHFrameSection;
1904   }
1905   const DWARFSection &getLineSection() const override { return LineSection; }
1906   StringRef getStrSection() const override { return StrSection; }
1907   const DWARFSection &getRangesSection() const override { return RangesSection; }
1908   const DWARFSection &getRnglistsSection() const override {
1909     return RnglistsSection;
1910   }
1911   const DWARFSection &getMacroSection() const override { return MacroSection; }
1912   StringRef getMacroDWOSection() const override { return MacroDWOSection; }
1913   StringRef getMacinfoSection() const override { return MacinfoSection; }
1914   StringRef getMacinfoDWOSection() const override { return MacinfoDWOSection; }
1915   const DWARFSection &getPubnamesSection() const override { return PubnamesSection; }
1916   const DWARFSection &getPubtypesSection() const override { return PubtypesSection; }
1917   const DWARFSection &getGnuPubnamesSection() const override {
1918     return GnuPubnamesSection;
1919   }
1920   const DWARFSection &getGnuPubtypesSection() const override {
1921     return GnuPubtypesSection;
1922   }
1923   const DWARFSection &getAppleNamesSection() const override {
1924     return AppleNamesSection;
1925   }
1926   const DWARFSection &getAppleTypesSection() const override {
1927     return AppleTypesSection;
1928   }
1929   const DWARFSection &getAppleNamespacesSection() const override {
1930     return AppleNamespacesSection;
1931   }
1932   const DWARFSection &getAppleObjCSection() const override {
1933     return AppleObjCSection;
1934   }
1935   const DWARFSection &getNamesSection() const override {
1936     return NamesSection;
1937   }
1938 
1939   StringRef getFileName() const override { return FileName; }
1940   uint8_t getAddressSize() const override { return AddressSize; }
1941   void forEachInfoSections(
1942       function_ref<void(const DWARFSection &)> F) const override {
1943     for (auto &P : InfoSections)
1944       F(P.second);
1945   }
1946   void forEachTypesSections(
1947       function_ref<void(const DWARFSection &)> F) const override {
1948     for (auto &P : TypesSections)
1949       F(P.second);
1950   }
1951 };
1952 } // namespace
1953 
1954 std::unique_ptr<DWARFContext>
1955 DWARFContext::create(const object::ObjectFile &Obj, const LoadedObjectInfo *L,
1956                      std::string DWPName,
1957                      std::function<void(Error)> RecoverableErrorHandler,
1958                      std::function<void(Error)> WarningHandler) {
1959   auto DObj =
1960       std::make_unique<DWARFObjInMemory>(Obj, L, RecoverableErrorHandler, WarningHandler);
1961   return std::make_unique<DWARFContext>(std::move(DObj), std::move(DWPName),
1962                                         RecoverableErrorHandler,
1963                                         WarningHandler);
1964 }
1965 
1966 std::unique_ptr<DWARFContext>
1967 DWARFContext::create(const StringMap<std::unique_ptr<MemoryBuffer>> &Sections,
1968                      uint8_t AddrSize, bool isLittleEndian,
1969                      std::function<void(Error)> RecoverableErrorHandler,
1970                      std::function<void(Error)> WarningHandler) {
1971   auto DObj =
1972       std::make_unique<DWARFObjInMemory>(Sections, AddrSize, isLittleEndian);
1973   return std::make_unique<DWARFContext>(
1974       std::move(DObj), "", RecoverableErrorHandler, WarningHandler);
1975 }
1976 
1977 Error DWARFContext::loadRegisterInfo(const object::ObjectFile &Obj) {
1978   // Detect the architecture from the object file. We usually don't need OS
1979   // info to lookup a target and create register info.
1980   Triple TT;
1981   TT.setArch(Triple::ArchType(Obj.getArch()));
1982   TT.setVendor(Triple::UnknownVendor);
1983   TT.setOS(Triple::UnknownOS);
1984   std::string TargetLookupError;
1985   const Target *TheTarget =
1986       TargetRegistry::lookupTarget(TT.str(), TargetLookupError);
1987   if (!TargetLookupError.empty())
1988     return createStringError(errc::invalid_argument,
1989                              TargetLookupError.c_str());
1990   RegInfo.reset(TheTarget->createMCRegInfo(TT.str()));
1991   return Error::success();
1992 }
1993 
1994 uint8_t DWARFContext::getCUAddrSize() {
1995   // In theory, different compile units may have different address byte
1996   // sizes, but for simplicity we just use the address byte size of the
1997   // first compile unit. In practice the address size field is repeated across
1998   // various DWARF headers (at least in version 5) to make it easier to dump
1999   // them independently, not to enable varying the address size.
2000   auto CUs = compile_units();
2001   return CUs.empty() ? 0 : (*CUs.begin())->getAddressByteSize();
2002 }
2003