xref: /freebsd-src/contrib/llvm-project/llvm/lib/DebugInfo/Symbolize/Symbolize.cpp (revision 5e801ac66d24704442eba426ed13c3effb8a34e7) 
1 //===-- LLVMSymbolize.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 // Implementation for LLVM symbolization library.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/DebugInfo/Symbolize/Symbolize.h"
14 
15 #include "SymbolizableObjectFile.h"
16 
17 #include "llvm/ADT/STLExtras.h"
18 #include "llvm/BinaryFormat/COFF.h"
19 #include "llvm/Config/config.h"
20 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
21 #include "llvm/DebugInfo/PDB/PDB.h"
22 #include "llvm/DebugInfo/PDB/PDBContext.h"
23 #include "llvm/Demangle/Demangle.h"
24 #include "llvm/Object/COFF.h"
25 #include "llvm/Object/MachO.h"
26 #include "llvm/Object/MachOUniversal.h"
27 #include "llvm/Support/CRC.h"
28 #include "llvm/Support/Casting.h"
29 #include "llvm/Support/Compression.h"
30 #include "llvm/Support/DataExtractor.h"
31 #include "llvm/Support/Errc.h"
32 #include "llvm/Support/FileSystem.h"
33 #include "llvm/Support/MemoryBuffer.h"
34 #include "llvm/Support/Path.h"
35 #include <algorithm>
36 #include <cassert>
37 #include <cstring>
38 
39 namespace llvm {
40 namespace symbolize {
41 
42 template <typename T>
43 Expected<DILineInfo>
44 LLVMSymbolizer::symbolizeCodeCommon(const T &ModuleSpecifier,
45                                     object::SectionedAddress ModuleOffset) {
46 
47   auto InfoOrErr = getOrCreateModuleInfo(ModuleSpecifier);
48   if (!InfoOrErr)
49     return InfoOrErr.takeError();
50 
51   SymbolizableModule *Info = *InfoOrErr;
52 
53   // A null module means an error has already been reported. Return an empty
54   // result.
55   if (!Info)
56     return DILineInfo();
57 
58   // If the user is giving us relative addresses, add the preferred base of the
59   // object to the offset before we do the query. It's what DIContext expects.
60   if (Opts.RelativeAddresses)
61     ModuleOffset.Address += Info->getModulePreferredBase();
62 
63   DILineInfo LineInfo = Info->symbolizeCode(
64       ModuleOffset, DILineInfoSpecifier(Opts.PathStyle, Opts.PrintFunctions),
65       Opts.UseSymbolTable);
66   if (Opts.Demangle)
67     LineInfo.FunctionName = DemangleName(LineInfo.FunctionName, Info);
68   return LineInfo;
69 }
70 
71 Expected<DILineInfo>
72 LLVMSymbolizer::symbolizeCode(const ObjectFile &Obj,
73                               object::SectionedAddress ModuleOffset) {
74   return symbolizeCodeCommon(Obj, ModuleOffset);
75 }
76 
77 Expected<DILineInfo>
78 LLVMSymbolizer::symbolizeCode(const std::string &ModuleName,
79                               object::SectionedAddress ModuleOffset) {
80   return symbolizeCodeCommon(ModuleName, ModuleOffset);
81 }
82 
83 template <typename T>
84 Expected<DIInliningInfo> LLVMSymbolizer::symbolizeInlinedCodeCommon(
85     const T &ModuleSpecifier, object::SectionedAddress ModuleOffset) {
86   auto InfoOrErr = getOrCreateModuleInfo(ModuleSpecifier);
87   if (!InfoOrErr)
88     return InfoOrErr.takeError();
89 
90   SymbolizableModule *Info = *InfoOrErr;
91 
92   // A null module means an error has already been reported. Return an empty
93   // result.
94   if (!Info)
95     return DIInliningInfo();
96 
97   // If the user is giving us relative addresses, add the preferred base of the
98   // object to the offset before we do the query. It's what DIContext expects.
99   if (Opts.RelativeAddresses)
100     ModuleOffset.Address += Info->getModulePreferredBase();
101 
102   DIInliningInfo InlinedContext = Info->symbolizeInlinedCode(
103       ModuleOffset, DILineInfoSpecifier(Opts.PathStyle, Opts.PrintFunctions),
104       Opts.UseSymbolTable);
105   if (Opts.Demangle) {
106     for (int i = 0, n = InlinedContext.getNumberOfFrames(); i < n; i++) {
107       auto *Frame = InlinedContext.getMutableFrame(i);
108       Frame->FunctionName = DemangleName(Frame->FunctionName, Info);
109     }
110   }
111   return InlinedContext;
112 }
113 
114 Expected<DIInliningInfo>
115 LLVMSymbolizer::symbolizeInlinedCode(const ObjectFile &Obj,
116                                      object::SectionedAddress ModuleOffset) {
117   return symbolizeInlinedCodeCommon(Obj, ModuleOffset);
118 }
119 
120 Expected<DIInliningInfo>
121 LLVMSymbolizer::symbolizeInlinedCode(const std::string &ModuleName,
122                                      object::SectionedAddress ModuleOffset) {
123   return symbolizeInlinedCodeCommon(ModuleName, ModuleOffset);
124 }
125 
126 template <typename T>
127 Expected<DIGlobal>
128 LLVMSymbolizer::symbolizeDataCommon(const T &ModuleSpecifier,
129                                     object::SectionedAddress ModuleOffset) {
130 
131   auto InfoOrErr = getOrCreateModuleInfo(ModuleSpecifier);
132   if (!InfoOrErr)
133     return InfoOrErr.takeError();
134 
135   SymbolizableModule *Info = *InfoOrErr;
136   // A null module means an error has already been reported. Return an empty
137   // result.
138   if (!Info)
139     return DIGlobal();
140 
141   // If the user is giving us relative addresses, add the preferred base of
142   // the object to the offset before we do the query. It's what DIContext
143   // expects.
144   if (Opts.RelativeAddresses)
145     ModuleOffset.Address += Info->getModulePreferredBase();
146 
147   DIGlobal Global = Info->symbolizeData(ModuleOffset);
148   if (Opts.Demangle)
149     Global.Name = DemangleName(Global.Name, Info);
150   return Global;
151 }
152 
153 Expected<DIGlobal>
154 LLVMSymbolizer::symbolizeData(const ObjectFile &Obj,
155                               object::SectionedAddress ModuleOffset) {
156   return symbolizeDataCommon(Obj, ModuleOffset);
157 }
158 
159 Expected<DIGlobal>
160 LLVMSymbolizer::symbolizeData(const std::string &ModuleName,
161                               object::SectionedAddress ModuleOffset) {
162   return symbolizeDataCommon(ModuleName, ModuleOffset);
163 }
164 
165 template <typename T>
166 Expected<std::vector<DILocal>>
167 LLVMSymbolizer::symbolizeFrameCommon(const T &ModuleSpecifier,
168                                      object::SectionedAddress ModuleOffset) {
169   auto InfoOrErr = getOrCreateModuleInfo(ModuleSpecifier);
170   if (!InfoOrErr)
171     return InfoOrErr.takeError();
172 
173   SymbolizableModule *Info = *InfoOrErr;
174   // A null module means an error has already been reported. Return an empty
175   // result.
176   if (!Info)
177     return std::vector<DILocal>();
178 
179   // If the user is giving us relative addresses, add the preferred base of
180   // the object to the offset before we do the query. It's what DIContext
181   // expects.
182   if (Opts.RelativeAddresses)
183     ModuleOffset.Address += Info->getModulePreferredBase();
184 
185   return Info->symbolizeFrame(ModuleOffset);
186 }
187 
188 Expected<std::vector<DILocal>>
189 LLVMSymbolizer::symbolizeFrame(const ObjectFile &Obj,
190                                object::SectionedAddress ModuleOffset) {
191   return symbolizeFrameCommon(Obj, ModuleOffset);
192 }
193 
194 Expected<std::vector<DILocal>>
195 LLVMSymbolizer::symbolizeFrame(const std::string &ModuleName,
196                                object::SectionedAddress ModuleOffset) {
197   return symbolizeFrameCommon(ModuleName, ModuleOffset);
198 }
199 
200 void LLVMSymbolizer::flush() {
201   ObjectForUBPathAndArch.clear();
202   BinaryForPath.clear();
203   ObjectPairForPathArch.clear();
204   Modules.clear();
205 }
206 
207 namespace {
208 
209 // For Path="/path/to/foo" and Basename="foo" assume that debug info is in
210 // /path/to/foo.dSYM/Contents/Resources/DWARF/foo.
211 // For Path="/path/to/bar.dSYM" and Basename="foo" assume that debug info is in
212 // /path/to/bar.dSYM/Contents/Resources/DWARF/foo.
213 std::string getDarwinDWARFResourceForPath(const std::string &Path,
214                                           const std::string &Basename) {
215   SmallString<16> ResourceName = StringRef(Path);
216   if (sys::path::extension(Path) != ".dSYM") {
217     ResourceName += ".dSYM";
218   }
219   sys::path::append(ResourceName, "Contents", "Resources", "DWARF");
220   sys::path::append(ResourceName, Basename);
221   return std::string(ResourceName.str());
222 }
223 
224 bool checkFileCRC(StringRef Path, uint32_t CRCHash) {
225   ErrorOr<std::unique_ptr<MemoryBuffer>> MB =
226       MemoryBuffer::getFileOrSTDIN(Path);
227   if (!MB)
228     return false;
229   return CRCHash == llvm::crc32(arrayRefFromStringRef(MB.get()->getBuffer()));
230 }
231 
232 bool findDebugBinary(const std::string &OrigPath,
233                      const std::string &DebuglinkName, uint32_t CRCHash,
234                      const std::string &FallbackDebugPath,
235                      std::string &Result) {
236   SmallString<16> OrigDir(OrigPath);
237   llvm::sys::path::remove_filename(OrigDir);
238   SmallString<16> DebugPath = OrigDir;
239   // Try relative/path/to/original_binary/debuglink_name
240   llvm::sys::path::append(DebugPath, DebuglinkName);
241   if (checkFileCRC(DebugPath, CRCHash)) {
242     Result = std::string(DebugPath.str());
243     return true;
244   }
245   // Try relative/path/to/original_binary/.debug/debuglink_name
246   DebugPath = OrigDir;
247   llvm::sys::path::append(DebugPath, ".debug", DebuglinkName);
248   if (checkFileCRC(DebugPath, CRCHash)) {
249     Result = std::string(DebugPath.str());
250     return true;
251   }
252   // Make the path absolute so that lookups will go to
253   // "/usr/lib/debug/full/path/to/debug", not
254   // "/usr/lib/debug/to/debug"
255   llvm::sys::fs::make_absolute(OrigDir);
256   if (!FallbackDebugPath.empty()) {
257     // Try <FallbackDebugPath>/absolute/path/to/original_binary/debuglink_name
258     DebugPath = FallbackDebugPath;
259   } else {
260 #if defined(__NetBSD__)
261     // Try /usr/libdata/debug/absolute/path/to/original_binary/debuglink_name
262     DebugPath = "/usr/libdata/debug";
263 #else
264     // Try /usr/lib/debug/absolute/path/to/original_binary/debuglink_name
265     DebugPath = "/usr/lib/debug";
266 #endif
267   }
268   llvm::sys::path::append(DebugPath, llvm::sys::path::relative_path(OrigDir),
269                           DebuglinkName);
270   if (checkFileCRC(DebugPath, CRCHash)) {
271     Result = std::string(DebugPath.str());
272     return true;
273   }
274   return false;
275 }
276 
277 bool getGNUDebuglinkContents(const ObjectFile *Obj, std::string &DebugName,
278                              uint32_t &CRCHash) {
279   if (!Obj)
280     return false;
281   for (const SectionRef &Section : Obj->sections()) {
282     StringRef Name;
283     consumeError(Section.getName().moveInto(Name));
284 
285     Name = Name.substr(Name.find_first_not_of("._"));
286     if (Name == "gnu_debuglink") {
287       Expected<StringRef> ContentsOrErr = Section.getContents();
288       if (!ContentsOrErr) {
289         consumeError(ContentsOrErr.takeError());
290         return false;
291       }
292       DataExtractor DE(*ContentsOrErr, Obj->isLittleEndian(), 0);
293       uint64_t Offset = 0;
294       if (const char *DebugNameStr = DE.getCStr(&Offset)) {
295         // 4-byte align the offset.
296         Offset = (Offset + 3) & ~0x3;
297         if (DE.isValidOffsetForDataOfSize(Offset, 4)) {
298           DebugName = DebugNameStr;
299           CRCHash = DE.getU32(&Offset);
300           return true;
301         }
302       }
303       break;
304     }
305   }
306   return false;
307 }
308 
309 bool darwinDsymMatchesBinary(const MachOObjectFile *DbgObj,
310                              const MachOObjectFile *Obj) {
311   ArrayRef<uint8_t> dbg_uuid = DbgObj->getUuid();
312   ArrayRef<uint8_t> bin_uuid = Obj->getUuid();
313   if (dbg_uuid.empty() || bin_uuid.empty())
314     return false;
315   return !memcmp(dbg_uuid.data(), bin_uuid.data(), dbg_uuid.size());
316 }
317 
318 template <typename ELFT>
319 Optional<ArrayRef<uint8_t>> getBuildID(const ELFFile<ELFT> &Obj) {
320   auto PhdrsOrErr = Obj.program_headers();
321   if (!PhdrsOrErr) {
322     consumeError(PhdrsOrErr.takeError());
323     return {};
324   }
325   for (const auto &P : *PhdrsOrErr) {
326     if (P.p_type != ELF::PT_NOTE)
327       continue;
328     Error Err = Error::success();
329     for (auto N : Obj.notes(P, Err))
330       if (N.getType() == ELF::NT_GNU_BUILD_ID &&
331           N.getName() == ELF::ELF_NOTE_GNU)
332         return N.getDesc();
333     consumeError(std::move(Err));
334   }
335   return {};
336 }
337 
338 Optional<ArrayRef<uint8_t>> getBuildID(const ELFObjectFileBase *Obj) {
339   Optional<ArrayRef<uint8_t>> BuildID;
340   if (auto *O = dyn_cast<ELFObjectFile<ELF32LE>>(Obj))
341     BuildID = getBuildID(O->getELFFile());
342   else if (auto *O = dyn_cast<ELFObjectFile<ELF32BE>>(Obj))
343     BuildID = getBuildID(O->getELFFile());
344   else if (auto *O = dyn_cast<ELFObjectFile<ELF64LE>>(Obj))
345     BuildID = getBuildID(O->getELFFile());
346   else if (auto *O = dyn_cast<ELFObjectFile<ELF64BE>>(Obj))
347     BuildID = getBuildID(O->getELFFile());
348   else
349     llvm_unreachable("unsupported file format");
350   return BuildID;
351 }
352 
353 bool findDebugBinary(const std::vector<std::string> &DebugFileDirectory,
354                      const ArrayRef<uint8_t> BuildID, std::string &Result) {
355   auto getDebugPath = [&](StringRef Directory) {
356     SmallString<128> Path{Directory};
357     sys::path::append(Path, ".build-id",
358                       llvm::toHex(BuildID[0], /*LowerCase=*/true),
359                       llvm::toHex(BuildID.slice(1), /*LowerCase=*/true));
360     Path += ".debug";
361     return Path;
362   };
363   if (DebugFileDirectory.empty()) {
364     SmallString<128> Path = getDebugPath(
365 #if defined(__NetBSD__)
366         // Try /usr/libdata/debug/.build-id/../...
367         "/usr/libdata/debug"
368 #else
369         // Try /usr/lib/debug/.build-id/../...
370         "/usr/lib/debug"
371 #endif
372     );
373     if (llvm::sys::fs::exists(Path)) {
374       Result = std::string(Path.str());
375       return true;
376     }
377   } else {
378     for (const auto &Directory : DebugFileDirectory) {
379       // Try <debug-file-directory>/.build-id/../...
380       SmallString<128> Path = getDebugPath(Directory);
381       if (llvm::sys::fs::exists(Path)) {
382         Result = std::string(Path.str());
383         return true;
384       }
385     }
386   }
387   return false;
388 }
389 
390 } // end anonymous namespace
391 
392 ObjectFile *LLVMSymbolizer::lookUpDsymFile(const std::string &ExePath,
393                                            const MachOObjectFile *MachExeObj,
394                                            const std::string &ArchName) {
395   // On Darwin we may find DWARF in separate object file in
396   // resource directory.
397   std::vector<std::string> DsymPaths;
398   StringRef Filename = sys::path::filename(ExePath);
399   DsymPaths.push_back(
400       getDarwinDWARFResourceForPath(ExePath, std::string(Filename)));
401   for (const auto &Path : Opts.DsymHints) {
402     DsymPaths.push_back(
403         getDarwinDWARFResourceForPath(Path, std::string(Filename)));
404   }
405   for (const auto &Path : DsymPaths) {
406     auto DbgObjOrErr = getOrCreateObject(Path, ArchName);
407     if (!DbgObjOrErr) {
408       // Ignore errors, the file might not exist.
409       consumeError(DbgObjOrErr.takeError());
410       continue;
411     }
412     ObjectFile *DbgObj = DbgObjOrErr.get();
413     if (!DbgObj)
414       continue;
415     const MachOObjectFile *MachDbgObj = dyn_cast<const MachOObjectFile>(DbgObj);
416     if (!MachDbgObj)
417       continue;
418     if (darwinDsymMatchesBinary(MachDbgObj, MachExeObj))
419       return DbgObj;
420   }
421   return nullptr;
422 }
423 
424 ObjectFile *LLVMSymbolizer::lookUpDebuglinkObject(const std::string &Path,
425                                                   const ObjectFile *Obj,
426                                                   const std::string &ArchName) {
427   std::string DebuglinkName;
428   uint32_t CRCHash;
429   std::string DebugBinaryPath;
430   if (!getGNUDebuglinkContents(Obj, DebuglinkName, CRCHash))
431     return nullptr;
432   if (!findDebugBinary(Path, DebuglinkName, CRCHash, Opts.FallbackDebugPath,
433                        DebugBinaryPath))
434     return nullptr;
435   auto DbgObjOrErr = getOrCreateObject(DebugBinaryPath, ArchName);
436   if (!DbgObjOrErr) {
437     // Ignore errors, the file might not exist.
438     consumeError(DbgObjOrErr.takeError());
439     return nullptr;
440   }
441   return DbgObjOrErr.get();
442 }
443 
444 ObjectFile *LLVMSymbolizer::lookUpBuildIDObject(const std::string &Path,
445                                                 const ELFObjectFileBase *Obj,
446                                                 const std::string &ArchName) {
447   auto BuildID = getBuildID(Obj);
448   if (!BuildID)
449     return nullptr;
450   if (BuildID->size() < 2)
451     return nullptr;
452   std::string DebugBinaryPath;
453   if (!findDebugBinary(Opts.DebugFileDirectory, *BuildID, DebugBinaryPath))
454     return nullptr;
455   auto DbgObjOrErr = getOrCreateObject(DebugBinaryPath, ArchName);
456   if (!DbgObjOrErr) {
457     consumeError(DbgObjOrErr.takeError());
458     return nullptr;
459   }
460   return DbgObjOrErr.get();
461 }
462 
463 Expected<LLVMSymbolizer::ObjectPair>
464 LLVMSymbolizer::getOrCreateObjectPair(const std::string &Path,
465                                       const std::string &ArchName) {
466   auto I = ObjectPairForPathArch.find(std::make_pair(Path, ArchName));
467   if (I != ObjectPairForPathArch.end())
468     return I->second;
469 
470   auto ObjOrErr = getOrCreateObject(Path, ArchName);
471   if (!ObjOrErr) {
472     ObjectPairForPathArch.emplace(std::make_pair(Path, ArchName),
473                                   ObjectPair(nullptr, nullptr));
474     return ObjOrErr.takeError();
475   }
476 
477   ObjectFile *Obj = ObjOrErr.get();
478   assert(Obj != nullptr);
479   ObjectFile *DbgObj = nullptr;
480 
481   if (auto MachObj = dyn_cast<const MachOObjectFile>(Obj))
482     DbgObj = lookUpDsymFile(Path, MachObj, ArchName);
483   else if (auto ELFObj = dyn_cast<const ELFObjectFileBase>(Obj))
484     DbgObj = lookUpBuildIDObject(Path, ELFObj, ArchName);
485   if (!DbgObj)
486     DbgObj = lookUpDebuglinkObject(Path, Obj, ArchName);
487   if (!DbgObj)
488     DbgObj = Obj;
489   ObjectPair Res = std::make_pair(Obj, DbgObj);
490   ObjectPairForPathArch.emplace(std::make_pair(Path, ArchName), Res);
491   return Res;
492 }
493 
494 Expected<ObjectFile *>
495 LLVMSymbolizer::getOrCreateObject(const std::string &Path,
496                                   const std::string &ArchName) {
497   Binary *Bin;
498   auto Pair = BinaryForPath.emplace(Path, OwningBinary<Binary>());
499   if (!Pair.second) {
500     Bin = Pair.first->second.getBinary();
501   } else {
502     Expected<OwningBinary<Binary>> BinOrErr = createBinary(Path);
503     if (!BinOrErr)
504       return BinOrErr.takeError();
505     Pair.first->second = std::move(BinOrErr.get());
506     Bin = Pair.first->second.getBinary();
507   }
508 
509   if (!Bin)
510     return static_cast<ObjectFile *>(nullptr);
511 
512   if (MachOUniversalBinary *UB = dyn_cast_or_null<MachOUniversalBinary>(Bin)) {
513     auto I = ObjectForUBPathAndArch.find(std::make_pair(Path, ArchName));
514     if (I != ObjectForUBPathAndArch.end())
515       return I->second.get();
516 
517     Expected<std::unique_ptr<ObjectFile>> ObjOrErr =
518         UB->getMachOObjectForArch(ArchName);
519     if (!ObjOrErr) {
520       ObjectForUBPathAndArch.emplace(std::make_pair(Path, ArchName),
521                                      std::unique_ptr<ObjectFile>());
522       return ObjOrErr.takeError();
523     }
524     ObjectFile *Res = ObjOrErr->get();
525     ObjectForUBPathAndArch.emplace(std::make_pair(Path, ArchName),
526                                    std::move(ObjOrErr.get()));
527     return Res;
528   }
529   if (Bin->isObject()) {
530     return cast<ObjectFile>(Bin);
531   }
532   return errorCodeToError(object_error::arch_not_found);
533 }
534 
535 Expected<SymbolizableModule *>
536 LLVMSymbolizer::createModuleInfo(const ObjectFile *Obj,
537                                  std::unique_ptr<DIContext> Context,
538                                  StringRef ModuleName) {
539   auto InfoOrErr = SymbolizableObjectFile::create(Obj, std::move(Context),
540                                                   Opts.UntagAddresses);
541   std::unique_ptr<SymbolizableModule> SymMod;
542   if (InfoOrErr)
543     SymMod = std::move(*InfoOrErr);
544   auto InsertResult = Modules.insert(
545       std::make_pair(std::string(ModuleName), std::move(SymMod)));
546   assert(InsertResult.second);
547   if (!InfoOrErr)
548     return InfoOrErr.takeError();
549   return InsertResult.first->second.get();
550 }
551 
552 Expected<SymbolizableModule *>
553 LLVMSymbolizer::getOrCreateModuleInfo(const std::string &ModuleName) {
554   auto I = Modules.find(ModuleName);
555   if (I != Modules.end())
556     return I->second.get();
557 
558   std::string BinaryName = ModuleName;
559   std::string ArchName = Opts.DefaultArch;
560   size_t ColonPos = ModuleName.find_last_of(':');
561   // Verify that substring after colon form a valid arch name.
562   if (ColonPos != std::string::npos) {
563     std::string ArchStr = ModuleName.substr(ColonPos + 1);
564     if (Triple(ArchStr).getArch() != Triple::UnknownArch) {
565       BinaryName = ModuleName.substr(0, ColonPos);
566       ArchName = ArchStr;
567     }
568   }
569   auto ObjectsOrErr = getOrCreateObjectPair(BinaryName, ArchName);
570   if (!ObjectsOrErr) {
571     // Failed to find valid object file.
572     Modules.emplace(ModuleName, std::unique_ptr<SymbolizableModule>());
573     return ObjectsOrErr.takeError();
574   }
575   ObjectPair Objects = ObjectsOrErr.get();
576 
577   std::unique_ptr<DIContext> Context;
578   // If this is a COFF object containing PDB info, use a PDBContext to
579   // symbolize. Otherwise, use DWARF.
580   if (auto CoffObject = dyn_cast<COFFObjectFile>(Objects.first)) {
581     const codeview::DebugInfo *DebugInfo;
582     StringRef PDBFileName;
583     auto EC = CoffObject->getDebugPDBInfo(DebugInfo, PDBFileName);
584     if (!EC && DebugInfo != nullptr && !PDBFileName.empty()) {
585 #if 0
586       using namespace pdb;
587       std::unique_ptr<IPDBSession> Session;
588 
589       PDB_ReaderType ReaderType =
590           Opts.UseDIA ? PDB_ReaderType::DIA : PDB_ReaderType::Native;
591       if (auto Err = loadDataForEXE(ReaderType, Objects.first->getFileName(),
592                                     Session)) {
593         Modules.emplace(ModuleName, std::unique_ptr<SymbolizableModule>());
594         // Return along the PDB filename to provide more context
595         return createFileError(PDBFileName, std::move(Err));
596       }
597       Context.reset(new PDBContext(*CoffObject, std::move(Session)));
598 #else
599       return make_error<StringError>(
600           "PDB support not compiled in",
601           std::make_error_code(std::errc::not_supported));
602 #endif
603     }
604   }
605   if (!Context)
606     Context = DWARFContext::create(
607         *Objects.second, DWARFContext::ProcessDebugRelocations::Process,
608         nullptr, Opts.DWPName);
609   return createModuleInfo(Objects.first, std::move(Context), ModuleName);
610 }
611 
612 Expected<SymbolizableModule *>
613 LLVMSymbolizer::getOrCreateModuleInfo(const ObjectFile &Obj) {
614   StringRef ObjName = Obj.getFileName();
615   auto I = Modules.find(ObjName);
616   if (I != Modules.end())
617     return I->second.get();
618 
619   std::unique_ptr<DIContext> Context = DWARFContext::create(Obj);
620   // FIXME: handle COFF object with PDB info to use PDBContext
621   return createModuleInfo(&Obj, std::move(Context), ObjName);
622 }
623 
624 namespace {
625 
626 // Undo these various manglings for Win32 extern "C" functions:
627 // cdecl       - _foo
628 // stdcall     - _foo@12
629 // fastcall    - @foo@12
630 // vectorcall  - foo@@12
631 // These are all different linkage names for 'foo'.
632 StringRef demanglePE32ExternCFunc(StringRef SymbolName) {
633   // Remove any '_' or '@' prefix.
634   char Front = SymbolName.empty() ? '\0' : SymbolName[0];
635   if (Front == '_' || Front == '@')
636     SymbolName = SymbolName.drop_front();
637 
638   // Remove any '@[0-9]+' suffix.
639   if (Front != '?') {
640     size_t AtPos = SymbolName.rfind('@');
641     if (AtPos != StringRef::npos &&
642         all_of(drop_begin(SymbolName, AtPos + 1), isDigit))
643       SymbolName = SymbolName.substr(0, AtPos);
644   }
645 
646   // Remove any ending '@' for vectorcall.
647   if (SymbolName.endswith("@"))
648     SymbolName = SymbolName.drop_back();
649 
650   return SymbolName;
651 }
652 
653 } // end anonymous namespace
654 
655 std::string
656 LLVMSymbolizer::DemangleName(const std::string &Name,
657                              const SymbolizableModule *DbiModuleDescriptor) {
658   std::string Result;
659   if (nonMicrosoftDemangle(Name.c_str(), Result))
660     return Result;
661 
662   if (!Name.empty() && Name.front() == '?') {
663     // Only do MSVC C++ demangling on symbols starting with '?'.
664     int status = 0;
665     char *DemangledName = microsoftDemangle(
666         Name.c_str(), nullptr, nullptr, nullptr, &status,
667         MSDemangleFlags(MSDF_NoAccessSpecifier | MSDF_NoCallingConvention |
668                         MSDF_NoMemberType | MSDF_NoReturnType));
669     if (status != 0)
670       return Name;
671     Result = DemangledName;
672     free(DemangledName);
673     return Result;
674   }
675 
676   if (DbiModuleDescriptor && DbiModuleDescriptor->isWin32Module())
677     return std::string(demanglePE32ExternCFunc(Name));
678   return Name;
679 }
680 
681 } // namespace symbolize
682 } // namespace llvm
683