xref: /llvm-project/llvm/tools/dsymutil/MachODebugMapParser.cpp (revision d0141ef232dfc2ae9602d1fcdf41e0209826d899)
1 //===- tools/dsymutil/MachODebugMapParser.cpp - Parse STABS debug maps ----===//
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 "BinaryHolder.h"
10 #include "DebugMap.h"
11 #include "MachOUtils.h"
12 #include "llvm/ADT/Optional.h"
13 #include "llvm/ADT/SmallSet.h"
14 #include "llvm/Object/MachO.h"
15 #include "llvm/Support/Path.h"
16 #include "llvm/Support/WithColor.h"
17 #include "llvm/Support/raw_ostream.h"
18 #include <vector>
19 
20 namespace {
21 using namespace llvm;
22 using namespace llvm::dsymutil;
23 using namespace llvm::object;
24 
25 class MachODebugMapParser {
26 public:
27   MachODebugMapParser(llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
28                       StringRef BinaryPath, ArrayRef<std::string> Archs,
29                       StringRef PathPrefix = "",
30                       bool PaperTrailWarnings = false, bool Verbose = false)
31       : BinaryPath(std::string(BinaryPath)), Archs(Archs.begin(), Archs.end()),
32         PathPrefix(std::string(PathPrefix)),
33         PaperTrailWarnings(PaperTrailWarnings), BinHolder(VFS, Verbose),
34         CurrentDebugMapObject(nullptr) {}
35 
36   /// Parses and returns the DebugMaps of the input binary. The binary contains
37   /// multiple maps in case it is a universal binary.
38   /// \returns an error in case the provided BinaryPath doesn't exist
39   /// or isn't of a supported type.
40   ErrorOr<std::vector<std::unique_ptr<DebugMap>>> parse();
41 
42   /// Walk the symbol table and dump it.
43   bool dumpStab();
44 
45 private:
46   std::string BinaryPath;
47   SmallVector<StringRef, 1> Archs;
48   std::string PathPrefix;
49   bool PaperTrailWarnings;
50 
51   /// Owns the MemoryBuffer for the main binary.
52   BinaryHolder BinHolder;
53   /// Map of the binary symbol addresses.
54   StringMap<uint64_t> MainBinarySymbolAddresses;
55   StringRef MainBinaryStrings;
56   /// The constructed DebugMap.
57   std::unique_ptr<DebugMap> Result;
58   /// List of common symbols that need to be added to the debug map.
59   std::vector<std::string> CommonSymbols;
60 
61   /// Map of the currently processed object file symbol addresses.
62   StringMap<Optional<uint64_t>> CurrentObjectAddresses;
63 
64   /// Lazily computed map of symbols aliased to the processed object file.
65   StringMap<Optional<uint64_t>> CurrentObjectAliasMap;
66 
67   /// If CurrentObjectAliasMap has been computed for a given address.
68   SmallSet<uint64_t, 4> SeenAliasValues;
69 
70   /// Element of the debug map corresponding to the current object file.
71   DebugMapObject *CurrentDebugMapObject;
72 
73   /// Holds function info while function scope processing.
74   const char *CurrentFunctionName;
75   uint64_t CurrentFunctionAddress;
76 
77   std::unique_ptr<DebugMap> parseOneBinary(const MachOObjectFile &MainBinary,
78                                            StringRef BinaryPath);
79 
80   void
81   switchToNewDebugMapObject(StringRef Filename,
82                             sys::TimePoint<std::chrono::seconds> Timestamp);
83   void resetParserState();
84   uint64_t getMainBinarySymbolAddress(StringRef Name);
85   std::vector<StringRef> getMainBinarySymbolNames(uint64_t Value);
86   void loadMainBinarySymbols(const MachOObjectFile &MainBinary);
87   void loadCurrentObjectFileSymbols(const object::MachOObjectFile &Obj);
88   void handleStabSymbolTableEntry(uint32_t StringIndex, uint8_t Type,
89                                   uint8_t SectionIndex, uint16_t Flags,
90                                   uint64_t Value);
91 
92   template <typename STEType> void handleStabDebugMapEntry(const STEType &STE) {
93     handleStabSymbolTableEntry(STE.n_strx, STE.n_type, STE.n_sect, STE.n_desc,
94                                STE.n_value);
95   }
96 
97   void addCommonSymbols();
98 
99   /// Dump the symbol table output header.
100   void dumpSymTabHeader(raw_ostream &OS, StringRef Arch);
101 
102   /// Dump the contents of nlist entries.
103   void dumpSymTabEntry(raw_ostream &OS, uint64_t Index, uint32_t StringIndex,
104                        uint8_t Type, uint8_t SectionIndex, uint16_t Flags,
105                        uint64_t Value);
106 
107   template <typename STEType>
108   void dumpSymTabEntry(raw_ostream &OS, uint64_t Index, const STEType &STE) {
109     dumpSymTabEntry(OS, Index, STE.n_strx, STE.n_type, STE.n_sect, STE.n_desc,
110                     STE.n_value);
111   }
112   void dumpOneBinaryStab(const MachOObjectFile &MainBinary,
113                          StringRef BinaryPath);
114 
115   void Warning(const Twine &Msg, StringRef File = StringRef()) {
116     WithColor::warning() << "("
117                          << MachOUtils::getArchName(
118                                 Result->getTriple().getArchName())
119                          << ") " << File << " " << Msg << "\n";
120 
121     if (PaperTrailWarnings) {
122       if (!File.empty())
123         Result->addDebugMapObject(File, sys::TimePoint<std::chrono::seconds>());
124       if (Result->end() != Result->begin())
125         (*--Result->end())->addWarning(Msg.str());
126     }
127   }
128 };
129 
130 } // anonymous namespace
131 
132 /// Reset the parser state corresponding to the current object
133 /// file. This is to be called after an object file is finished
134 /// processing.
135 void MachODebugMapParser::resetParserState() {
136   CommonSymbols.clear();
137   CurrentObjectAddresses.clear();
138   CurrentObjectAliasMap.clear();
139   SeenAliasValues.clear();
140   CurrentDebugMapObject = nullptr;
141 }
142 
143 /// Commons symbols won't show up in the symbol map but might need to be
144 /// relocated. We can add them to the symbol table ourselves by combining the
145 /// information in the object file (the symbol name) and the main binary (the
146 /// address).
147 void MachODebugMapParser::addCommonSymbols() {
148   for (auto &CommonSymbol : CommonSymbols) {
149     uint64_t CommonAddr = getMainBinarySymbolAddress(CommonSymbol);
150     if (CommonAddr == 0) {
151       // The main binary doesn't have an address for the given symbol.
152       continue;
153     }
154     if (!CurrentDebugMapObject->addSymbol(CommonSymbol, None /*ObjectAddress*/,
155                                           CommonAddr, 0 /*size*/)) {
156       // The symbol is already present.
157       continue;
158     }
159   }
160 }
161 
162 /// Create a new DebugMapObject. This function resets the state of the
163 /// parser that was referring to the last object file and sets
164 /// everything up to add symbols to the new one.
165 void MachODebugMapParser::switchToNewDebugMapObject(
166     StringRef Filename, sys::TimePoint<std::chrono::seconds> Timestamp) {
167   addCommonSymbols();
168   resetParserState();
169 
170   SmallString<80> Path(PathPrefix);
171   sys::path::append(Path, Filename);
172 
173   auto ObjectEntry = BinHolder.getObjectEntry(Path, Timestamp);
174   if (!ObjectEntry) {
175     auto Err = ObjectEntry.takeError();
176     Warning("unable to open object file: " + toString(std::move(Err)),
177             Path.str());
178     return;
179   }
180 
181   auto Object = ObjectEntry->getObjectAs<MachOObjectFile>(Result->getTriple());
182   if (!Object) {
183     auto Err = Object.takeError();
184     Warning("unable to open object file: " + toString(std::move(Err)),
185             Path.str());
186     return;
187   }
188 
189   CurrentDebugMapObject =
190       &Result->addDebugMapObject(Path, Timestamp, MachO::N_OSO);
191   loadCurrentObjectFileSymbols(*Object);
192 }
193 
194 static std::string getArchName(const object::MachOObjectFile &Obj) {
195   Triple T = Obj.getArchTriple();
196   return std::string(T.getArchName());
197 }
198 
199 std::unique_ptr<DebugMap>
200 MachODebugMapParser::parseOneBinary(const MachOObjectFile &MainBinary,
201                                     StringRef BinaryPath) {
202   loadMainBinarySymbols(MainBinary);
203   ArrayRef<uint8_t> UUID = MainBinary.getUuid();
204   Result =
205       std::make_unique<DebugMap>(MainBinary.getArchTriple(), BinaryPath, UUID);
206   MainBinaryStrings = MainBinary.getStringTableData();
207   for (const SymbolRef &Symbol : MainBinary.symbols()) {
208     const DataRefImpl &DRI = Symbol.getRawDataRefImpl();
209     if (MainBinary.is64Bit())
210       handleStabDebugMapEntry(MainBinary.getSymbol64TableEntry(DRI));
211     else
212       handleStabDebugMapEntry(MainBinary.getSymbolTableEntry(DRI));
213   }
214 
215   resetParserState();
216   return std::move(Result);
217 }
218 
219 // Table that maps Darwin's Mach-O stab constants to strings to allow printing.
220 // llvm-nm has very similar code, the strings used here are however slightly
221 // different and part of the interface of dsymutil (some project's build-systems
222 // parse the ouptut of dsymutil -s), thus they shouldn't be changed.
223 struct DarwinStabName {
224   uint8_t NType;
225   const char *Name;
226 };
227 
228 const struct DarwinStabName DarwinStabNames[] = {
229     {MachO::N_GSYM, "N_GSYM"},    {MachO::N_FNAME, "N_FNAME"},
230     {MachO::N_FUN, "N_FUN"},      {MachO::N_STSYM, "N_STSYM"},
231     {MachO::N_LCSYM, "N_LCSYM"},  {MachO::N_BNSYM, "N_BNSYM"},
232     {MachO::N_PC, "N_PC"},        {MachO::N_AST, "N_AST"},
233     {MachO::N_OPT, "N_OPT"},      {MachO::N_RSYM, "N_RSYM"},
234     {MachO::N_SLINE, "N_SLINE"},  {MachO::N_ENSYM, "N_ENSYM"},
235     {MachO::N_SSYM, "N_SSYM"},    {MachO::N_SO, "N_SO"},
236     {MachO::N_OSO, "N_OSO"},      {MachO::N_LSYM, "N_LSYM"},
237     {MachO::N_BINCL, "N_BINCL"},  {MachO::N_SOL, "N_SOL"},
238     {MachO::N_PARAMS, "N_PARAM"}, {MachO::N_VERSION, "N_VERS"},
239     {MachO::N_OLEVEL, "N_OLEV"},  {MachO::N_PSYM, "N_PSYM"},
240     {MachO::N_EINCL, "N_EINCL"},  {MachO::N_ENTRY, "N_ENTRY"},
241     {MachO::N_LBRAC, "N_LBRAC"},  {MachO::N_EXCL, "N_EXCL"},
242     {MachO::N_RBRAC, "N_RBRAC"},  {MachO::N_BCOMM, "N_BCOMM"},
243     {MachO::N_ECOMM, "N_ECOMM"},  {MachO::N_ECOML, "N_ECOML"},
244     {MachO::N_LENG, "N_LENG"},    {0, nullptr}};
245 
246 static const char *getDarwinStabString(uint8_t NType) {
247   for (unsigned i = 0; DarwinStabNames[i].Name; i++) {
248     if (DarwinStabNames[i].NType == NType)
249       return DarwinStabNames[i].Name;
250   }
251   return nullptr;
252 }
253 
254 void MachODebugMapParser::dumpSymTabHeader(raw_ostream &OS, StringRef Arch) {
255   OS << "-----------------------------------"
256         "-----------------------------------\n";
257   OS << "Symbol table for: '" << BinaryPath << "' (" << Arch.data() << ")\n";
258   OS << "-----------------------------------"
259         "-----------------------------------\n";
260   OS << "Index    n_strx   n_type             n_sect n_desc n_value\n";
261   OS << "======== -------- ------------------ ------ ------ ----------------\n";
262 }
263 
264 void MachODebugMapParser::dumpSymTabEntry(raw_ostream &OS, uint64_t Index,
265                                           uint32_t StringIndex, uint8_t Type,
266                                           uint8_t SectionIndex, uint16_t Flags,
267                                           uint64_t Value) {
268   // Index
269   OS << '[' << format_decimal(Index, 6)
270      << "] "
271      // n_strx
272      << format_hex_no_prefix(StringIndex, 8)
273      << ' '
274      // n_type...
275      << format_hex_no_prefix(Type, 2) << " (";
276 
277   if (Type & MachO::N_STAB)
278     OS << left_justify(getDarwinStabString(Type), 13);
279   else {
280     if (Type & MachO::N_PEXT)
281       OS << "PEXT ";
282     else
283       OS << "     ";
284     switch (Type & MachO::N_TYPE) {
285     case MachO::N_UNDF: // 0x0 undefined, n_sect == NO_SECT
286       OS << "UNDF";
287       break;
288     case MachO::N_ABS: // 0x2 absolute, n_sect == NO_SECT
289       OS << "ABS ";
290       break;
291     case MachO::N_SECT: // 0xe defined in section number n_sect
292       OS << "SECT";
293       break;
294     case MachO::N_PBUD: // 0xc prebound undefined (defined in a dylib)
295       OS << "PBUD";
296       break;
297     case MachO::N_INDR: // 0xa indirect
298       OS << "INDR";
299       break;
300     default:
301       OS << format_hex_no_prefix(Type, 2) << "    ";
302       break;
303     }
304     if (Type & MachO::N_EXT)
305       OS << " EXT";
306     else
307       OS << "    ";
308   }
309 
310   OS << ") "
311      // n_sect
312      << format_hex_no_prefix(SectionIndex, 2)
313      << "     "
314      // n_desc
315      << format_hex_no_prefix(Flags, 4)
316      << "   "
317      // n_value
318      << format_hex_no_prefix(Value, 16);
319 
320   const char *Name = &MainBinaryStrings.data()[StringIndex];
321   if (Name && Name[0])
322     OS << " '" << Name << "'";
323 
324   OS << "\n";
325 }
326 
327 void MachODebugMapParser::dumpOneBinaryStab(const MachOObjectFile &MainBinary,
328                                             StringRef BinaryPath) {
329   loadMainBinarySymbols(MainBinary);
330   MainBinaryStrings = MainBinary.getStringTableData();
331   raw_ostream &OS(llvm::outs());
332 
333   dumpSymTabHeader(OS, getArchName(MainBinary));
334   uint64_t Idx = 0;
335   for (const SymbolRef &Symbol : MainBinary.symbols()) {
336     const DataRefImpl &DRI = Symbol.getRawDataRefImpl();
337     if (MainBinary.is64Bit())
338       dumpSymTabEntry(OS, Idx, MainBinary.getSymbol64TableEntry(DRI));
339     else
340       dumpSymTabEntry(OS, Idx, MainBinary.getSymbolTableEntry(DRI));
341     Idx++;
342   }
343 
344   OS << "\n\n";
345   resetParserState();
346 }
347 
348 static bool shouldLinkArch(SmallVectorImpl<StringRef> &Archs, StringRef Arch) {
349   if (Archs.empty() || is_contained(Archs, "all") || is_contained(Archs, "*"))
350     return true;
351 
352   if (Arch.startswith("arm") && Arch != "arm64" && is_contained(Archs, "arm"))
353     return true;
354 
355   SmallString<16> ArchName = Arch;
356   if (Arch.startswith("thumb"))
357     ArchName = ("arm" + Arch.substr(5)).str();
358 
359   return is_contained(Archs, ArchName);
360 }
361 
362 bool MachODebugMapParser::dumpStab() {
363   auto ObjectEntry = BinHolder.getObjectEntry(BinaryPath);
364   if (!ObjectEntry) {
365     auto Err = ObjectEntry.takeError();
366     WithColor::error() << "cannot load '" << BinaryPath
367                        << "': " << toString(std::move(Err)) << '\n';
368     return false;
369   }
370 
371   auto Objects = ObjectEntry->getObjectsAs<MachOObjectFile>();
372   if (!Objects) {
373     auto Err = Objects.takeError();
374     WithColor::error() << "cannot get '" << BinaryPath
375                        << "' as MachO file: " << toString(std::move(Err))
376                        << "\n";
377     return false;
378   }
379 
380   for (const auto *Object : *Objects)
381     if (shouldLinkArch(Archs, Object->getArchTriple().getArchName()))
382       dumpOneBinaryStab(*Object, BinaryPath);
383 
384   return true;
385 }
386 
387 /// This main parsing routine tries to open the main binary and if
388 /// successful iterates over the STAB entries. The real parsing is
389 /// done in handleStabSymbolTableEntry.
390 ErrorOr<std::vector<std::unique_ptr<DebugMap>>> MachODebugMapParser::parse() {
391   auto ObjectEntry = BinHolder.getObjectEntry(BinaryPath);
392   if (!ObjectEntry) {
393     return errorToErrorCode(ObjectEntry.takeError());
394   }
395 
396   auto Objects = ObjectEntry->getObjectsAs<MachOObjectFile>();
397   if (!Objects) {
398     return errorToErrorCode(Objects.takeError());
399   }
400 
401   std::vector<std::unique_ptr<DebugMap>> Results;
402   for (const auto *Object : *Objects)
403     if (shouldLinkArch(Archs, Object->getArchTriple().getArchName()))
404       Results.push_back(parseOneBinary(*Object, BinaryPath));
405 
406   return std::move(Results);
407 }
408 
409 /// Interpret the STAB entries to fill the DebugMap.
410 void MachODebugMapParser::handleStabSymbolTableEntry(uint32_t StringIndex,
411                                                      uint8_t Type,
412                                                      uint8_t SectionIndex,
413                                                      uint16_t Flags,
414                                                      uint64_t Value) {
415   if (!(Type & MachO::N_STAB))
416     return;
417 
418   const char *Name = &MainBinaryStrings.data()[StringIndex];
419 
420   // An N_OSO entry represents the start of a new object file description.
421   if (Type == MachO::N_OSO)
422     return switchToNewDebugMapObject(Name, sys::toTimePoint(Value));
423 
424   if (Type == MachO::N_AST) {
425     SmallString<80> Path(PathPrefix);
426     sys::path::append(Path, Name);
427     Result->addDebugMapObject(Path, sys::toTimePoint(Value), Type);
428     return;
429   }
430 
431   // If the last N_OSO object file wasn't found, CurrentDebugMapObject will be
432   // null. Do not update anything until we find the next valid N_OSO entry.
433   if (!CurrentDebugMapObject)
434     return;
435 
436   uint32_t Size = 0;
437   switch (Type) {
438   case MachO::N_GSYM:
439     // This is a global variable. We need to query the main binary
440     // symbol table to find its address as it might not be in the
441     // debug map (for common symbols).
442     Value = getMainBinarySymbolAddress(Name);
443     break;
444   case MachO::N_FUN:
445     // Functions are scopes in STABS. They have an end marker that
446     // contains the function size.
447     if (Name[0] == '\0') {
448       Size = Value;
449       Value = CurrentFunctionAddress;
450       Name = CurrentFunctionName;
451       break;
452     } else {
453       CurrentFunctionName = Name;
454       CurrentFunctionAddress = Value;
455       return;
456     }
457   case MachO::N_STSYM:
458     break;
459   default:
460     return;
461   }
462 
463   auto ObjectSymIt = CurrentObjectAddresses.find(Name);
464 
465   // If the name of a (non-static) symbol is not in the current object, we
466   // check all its aliases from the main binary.
467   if (ObjectSymIt == CurrentObjectAddresses.end() && Type != MachO::N_STSYM) {
468     if (SeenAliasValues.count(Value) == 0) {
469       auto Aliases = getMainBinarySymbolNames(Value);
470       for (const auto &Alias : Aliases) {
471         auto It = CurrentObjectAddresses.find(Alias);
472         if (It != CurrentObjectAddresses.end()) {
473           auto AliasValue = It->getValue();
474           for (const auto &Alias : Aliases)
475             CurrentObjectAliasMap[Alias] = AliasValue;
476           break;
477         }
478       }
479       SeenAliasValues.insert(Value);
480     }
481 
482     auto AliasIt = CurrentObjectAliasMap.find(Name);
483     if (AliasIt != CurrentObjectAliasMap.end())
484       ObjectSymIt = AliasIt;
485   }
486 
487   // ThinLTO adds a unique suffix to exported private symbols.
488   if (ObjectSymIt == CurrentObjectAddresses.end()) {
489     for (auto Iter = CurrentObjectAddresses.begin();
490          Iter != CurrentObjectAddresses.end(); ++Iter) {
491       llvm::StringRef SymbolName = Iter->getKey();
492       auto Pos = SymbolName.rfind(".llvm.");
493       if (Pos != llvm::StringRef::npos && SymbolName.substr(0, Pos) == Name) {
494         ObjectSymIt = Iter;
495         break;
496       }
497     }
498   }
499 
500   if (ObjectSymIt == CurrentObjectAddresses.end()) {
501     Warning("could not find object file symbol for symbol " + Twine(Name));
502     return;
503   }
504 
505   if (!CurrentDebugMapObject->addSymbol(Name, ObjectSymIt->getValue(), Value,
506                                         Size)) {
507     Warning(Twine("failed to insert symbol '") + Name + "' in the debug map.");
508     return;
509   }
510 }
511 
512 /// Load the current object file symbols into CurrentObjectAddresses.
513 void MachODebugMapParser::loadCurrentObjectFileSymbols(
514     const object::MachOObjectFile &Obj) {
515   CurrentObjectAddresses.clear();
516 
517   for (auto Sym : Obj.symbols()) {
518     uint64_t Addr = cantFail(Sym.getValue());
519     Expected<StringRef> Name = Sym.getName();
520     if (!Name) {
521       auto Err = Name.takeError();
522       Warning("failed to get symbol name: " + toString(std::move(Err)),
523               Obj.getFileName());
524       continue;
525     }
526     // The value of some categories of symbols isn't meaningful. For
527     // example common symbols store their size in the value field, not
528     // their address. Absolute symbols have a fixed address that can
529     // conflict with standard symbols. These symbols (especially the
530     // common ones), might still be referenced by relocations. These
531     // relocations will use the symbol itself, and won't need an
532     // object file address. The object file address field is optional
533     // in the DebugMap, leave it unassigned for these symbols.
534     uint32_t Flags = cantFail(Sym.getFlags());
535     if (Flags & SymbolRef::SF_Absolute) {
536       CurrentObjectAddresses[*Name] = None;
537     } else if (Flags & SymbolRef::SF_Common) {
538       CurrentObjectAddresses[*Name] = None;
539       CommonSymbols.push_back(std::string(*Name));
540     } else {
541       CurrentObjectAddresses[*Name] = Addr;
542     }
543   }
544 }
545 
546 /// Lookup a symbol address in the main binary symbol table. The
547 /// parser only needs to query common symbols, thus not every symbol's
548 /// address is available through this function.
549 uint64_t MachODebugMapParser::getMainBinarySymbolAddress(StringRef Name) {
550   auto Sym = MainBinarySymbolAddresses.find(Name);
551   if (Sym == MainBinarySymbolAddresses.end())
552     return 0;
553   return Sym->second;
554 }
555 
556 /// Get all symbol names in the main binary for the given value.
557 std::vector<StringRef>
558 MachODebugMapParser::getMainBinarySymbolNames(uint64_t Value) {
559   std::vector<StringRef> Names;
560   for (const auto &Entry : MainBinarySymbolAddresses) {
561     if (Entry.second == Value)
562       Names.push_back(Entry.first());
563   }
564   return Names;
565 }
566 
567 /// Load the interesting main binary symbols' addresses into
568 /// MainBinarySymbolAddresses.
569 void MachODebugMapParser::loadMainBinarySymbols(
570     const MachOObjectFile &MainBinary) {
571   section_iterator Section = MainBinary.section_end();
572   MainBinarySymbolAddresses.clear();
573   for (const auto &Sym : MainBinary.symbols()) {
574     Expected<SymbolRef::Type> TypeOrErr = Sym.getType();
575     if (!TypeOrErr) {
576       auto Err = TypeOrErr.takeError();
577       Warning("failed to get symbol type: " + toString(std::move(Err)),
578               MainBinary.getFileName());
579       continue;
580     }
581     SymbolRef::Type Type = *TypeOrErr;
582     // Skip undefined and STAB entries.
583     if ((Type == SymbolRef::ST_Debug) || (Type == SymbolRef::ST_Unknown))
584       continue;
585     // In theory, the only symbols of interest are the global variables. These
586     // are the only ones that need to be queried because the address of common
587     // data won't be described in the debug map. All other addresses should be
588     // fetched for the debug map. In reality, by playing with 'ld -r' and
589     // export lists, you can get symbols described as N_GSYM in the debug map,
590     // but associated with a local symbol. Gather all the symbols, but prefer
591     // the global ones.
592     uint8_t SymType =
593         MainBinary.getSymbolTableEntry(Sym.getRawDataRefImpl()).n_type;
594     bool Extern = SymType & (MachO::N_EXT | MachO::N_PEXT);
595     Expected<section_iterator> SectionOrErr = Sym.getSection();
596     if (!SectionOrErr) {
597       auto Err = TypeOrErr.takeError();
598       Warning("failed to get symbol section: " + toString(std::move(Err)),
599               MainBinary.getFileName());
600       continue;
601     }
602     Section = *SectionOrErr;
603     if ((Section == MainBinary.section_end() || Section->isText()) && !Extern)
604       continue;
605     uint64_t Addr = cantFail(Sym.getValue());
606     Expected<StringRef> NameOrErr = Sym.getName();
607     if (!NameOrErr) {
608       auto Err = NameOrErr.takeError();
609       Warning("failed to get symbol name: " + toString(std::move(Err)),
610               MainBinary.getFileName());
611       continue;
612     }
613     StringRef Name = *NameOrErr;
614     if (Name.size() == 0 || Name[0] == '\0')
615       continue;
616     // Override only if the new key is global.
617     if (Extern)
618       MainBinarySymbolAddresses[Name] = Addr;
619     else
620       MainBinarySymbolAddresses.try_emplace(Name, Addr);
621   }
622 }
623 
624 namespace llvm {
625 namespace dsymutil {
626 llvm::ErrorOr<std::vector<std::unique_ptr<DebugMap>>>
627 parseDebugMap(llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
628               StringRef InputFile, ArrayRef<std::string> Archs,
629               StringRef PrependPath, bool PaperTrailWarnings, bool Verbose,
630               bool InputIsYAML) {
631   if (InputIsYAML)
632     return DebugMap::parseYAMLDebugMap(InputFile, PrependPath, Verbose);
633 
634   MachODebugMapParser Parser(VFS, InputFile, Archs, PrependPath,
635                              PaperTrailWarnings, Verbose);
636   return Parser.parse();
637 }
638 
639 bool dumpStab(llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
640               StringRef InputFile, ArrayRef<std::string> Archs,
641               StringRef PrependPath) {
642   MachODebugMapParser Parser(VFS, InputFile, Archs, PrependPath, false);
643   return Parser.dumpStab();
644 }
645 } // namespace dsymutil
646 } // namespace llvm
647