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1 //===-- LLVMSymbolize.cpp -------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Implementation for LLVM symbolization library.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/DebugInfo/Symbolize/Symbolize.h"
15 
16 #include "SymbolizableObjectFile.h"
17 
18 #include "llvm/ADT/STLExtras.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/Object/COFF.h"
24 #include "llvm/Object/ELFObjectFile.h"
25 #include "llvm/Object/MachO.h"
26 #include "llvm/Object/MachOUniversal.h"
27 #include "llvm/Support/COFF.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 <cstdlib>
38 #include <cstring>
39 
40 #if defined(_MSC_VER)
41 #include <Windows.h>
42 #include <DbgHelp.h>
43 #pragma comment(lib, "dbghelp.lib")
44 
45 // Windows.h conflicts with our COFF header definitions.
46 #ifdef IMAGE_FILE_MACHINE_I386
47 #undef IMAGE_FILE_MACHINE_I386
48 #endif
49 #endif
50 
51 namespace llvm {
52 namespace symbolize {
53 
symbolizeCode(const std::string & ModuleName,uint64_t ModuleOffset)54 Expected<DILineInfo> LLVMSymbolizer::symbolizeCode(const std::string &ModuleName,
55                                                   uint64_t ModuleOffset) {
56   SymbolizableModule *Info;
57   if (auto InfoOrErr = getOrCreateModuleInfo(ModuleName))
58     Info = InfoOrErr.get();
59   else
60     return InfoOrErr.takeError();
61 
62   // A null module means an error has already been reported. Return an empty
63   // result.
64   if (!Info)
65     return DILineInfo();
66 
67   // If the user is giving us relative addresses, add the preferred base of the
68   // object to the offset before we do the query. It's what DIContext expects.
69   if (Opts.RelativeAddresses)
70     ModuleOffset += Info->getModulePreferredBase();
71 
72   DILineInfo LineInfo = Info->symbolizeCode(ModuleOffset, Opts.PrintFunctions,
73                                             Opts.UseSymbolTable);
74   if (Opts.Demangle)
75     LineInfo.FunctionName = DemangleName(LineInfo.FunctionName, Info);
76   return LineInfo;
77 }
78 
79 Expected<DIInliningInfo>
symbolizeInlinedCode(const std::string & ModuleName,uint64_t ModuleOffset)80 LLVMSymbolizer::symbolizeInlinedCode(const std::string &ModuleName,
81                                      uint64_t ModuleOffset) {
82   SymbolizableModule *Info;
83   if (auto InfoOrErr = getOrCreateModuleInfo(ModuleName))
84     Info = InfoOrErr.get();
85   else
86     return InfoOrErr.takeError();
87 
88   // A null module means an error has already been reported. Return an empty
89   // result.
90   if (!Info)
91     return DIInliningInfo();
92 
93   // If the user is giving us relative addresses, add the preferred base of the
94   // object to the offset before we do the query. It's what DIContext expects.
95   if (Opts.RelativeAddresses)
96     ModuleOffset += Info->getModulePreferredBase();
97 
98   DIInliningInfo InlinedContext = Info->symbolizeInlinedCode(
99       ModuleOffset, Opts.PrintFunctions, Opts.UseSymbolTable);
100   if (Opts.Demangle) {
101     for (int i = 0, n = InlinedContext.getNumberOfFrames(); i < n; i++) {
102       auto *Frame = InlinedContext.getMutableFrame(i);
103       Frame->FunctionName = DemangleName(Frame->FunctionName, Info);
104     }
105   }
106   return InlinedContext;
107 }
108 
symbolizeData(const std::string & ModuleName,uint64_t ModuleOffset)109 Expected<DIGlobal> LLVMSymbolizer::symbolizeData(const std::string &ModuleName,
110                                                  uint64_t ModuleOffset) {
111   SymbolizableModule *Info;
112   if (auto InfoOrErr = getOrCreateModuleInfo(ModuleName))
113     Info = InfoOrErr.get();
114   else
115     return InfoOrErr.takeError();
116 
117   // A null module means an error has already been reported. Return an empty
118   // result.
119   if (!Info)
120     return DIGlobal();
121 
122   // If the user is giving us relative addresses, add the preferred base of
123   // the object to the offset before we do the query. It's what DIContext
124   // expects.
125   if (Opts.RelativeAddresses)
126     ModuleOffset += Info->getModulePreferredBase();
127 
128   DIGlobal Global = Info->symbolizeData(ModuleOffset);
129   if (Opts.Demangle)
130     Global.Name = DemangleName(Global.Name, Info);
131   return Global;
132 }
133 
flush()134 void LLVMSymbolizer::flush() {
135   ObjectForUBPathAndArch.clear();
136   BinaryForPath.clear();
137   ObjectPairForPathArch.clear();
138   Modules.clear();
139 }
140 
141 namespace {
142 
143 // For Path="/path/to/foo" and Basename="foo" assume that debug info is in
144 // /path/to/foo.dSYM/Contents/Resources/DWARF/foo.
145 // For Path="/path/to/bar.dSYM" and Basename="foo" assume that debug info is in
146 // /path/to/bar.dSYM/Contents/Resources/DWARF/foo.
getDarwinDWARFResourceForPath(const std::string & Path,const std::string & Basename)147 std::string getDarwinDWARFResourceForPath(
148     const std::string &Path, const std::string &Basename) {
149   SmallString<16> ResourceName = StringRef(Path);
150   if (sys::path::extension(Path) != ".dSYM") {
151     ResourceName += ".dSYM";
152   }
153   sys::path::append(ResourceName, "Contents", "Resources", "DWARF");
154   sys::path::append(ResourceName, Basename);
155   return ResourceName.str();
156 }
157 
checkFileCRC(StringRef Path,uint32_t CRCHash)158 bool checkFileCRC(StringRef Path, uint32_t CRCHash) {
159   ErrorOr<std::unique_ptr<MemoryBuffer>> MB =
160       MemoryBuffer::getFileOrSTDIN(Path);
161   if (!MB)
162     return false;
163   return !zlib::isAvailable() || CRCHash == zlib::crc32(MB.get()->getBuffer());
164 }
165 
findDebugBinary(const std::string & OrigPath,const std::string & DebuglinkName,uint32_t CRCHash,std::string & Result)166 bool findDebugBinary(const std::string &OrigPath,
167                      const std::string &DebuglinkName, uint32_t CRCHash,
168                      std::string &Result) {
169   std::string OrigRealPath = OrigPath;
170 #if defined(HAVE_REALPATH)
171   if (char *RP = realpath(OrigPath.c_str(), nullptr)) {
172     OrigRealPath = RP;
173     free(RP);
174   }
175 #endif
176   SmallString<16> OrigDir(OrigRealPath);
177   llvm::sys::path::remove_filename(OrigDir);
178   SmallString<16> DebugPath = OrigDir;
179   // Try /path/to/original_binary/debuglink_name
180   llvm::sys::path::append(DebugPath, DebuglinkName);
181   if (checkFileCRC(DebugPath, CRCHash)) {
182     Result = DebugPath.str();
183     return true;
184   }
185   // Try /path/to/original_binary/.debug/debuglink_name
186   DebugPath = OrigRealPath;
187   llvm::sys::path::append(DebugPath, ".debug", DebuglinkName);
188   if (checkFileCRC(DebugPath, CRCHash)) {
189     Result = DebugPath.str();
190     return true;
191   }
192   // Try /usr/lib/debug/path/to/original_binary/debuglink_name
193   DebugPath = "/usr/lib/debug";
194   llvm::sys::path::append(DebugPath, llvm::sys::path::relative_path(OrigDir),
195                           DebuglinkName);
196   if (checkFileCRC(DebugPath, CRCHash)) {
197     Result = DebugPath.str();
198     return true;
199   }
200   return false;
201 }
202 
getGNUDebuglinkContents(const ObjectFile * Obj,std::string & DebugName,uint32_t & CRCHash)203 bool getGNUDebuglinkContents(const ObjectFile *Obj, std::string &DebugName,
204                              uint32_t &CRCHash) {
205   if (!Obj)
206     return false;
207   for (const SectionRef &Section : Obj->sections()) {
208     StringRef Name;
209     Section.getName(Name);
210     Name = Name.substr(Name.find_first_not_of("._"));
211     if (Name == "gnu_debuglink") {
212       StringRef Data;
213       Section.getContents(Data);
214       DataExtractor DE(Data, Obj->isLittleEndian(), 0);
215       uint32_t Offset = 0;
216       if (const char *DebugNameStr = DE.getCStr(&Offset)) {
217         // 4-byte align the offset.
218         Offset = (Offset + 3) & ~0x3;
219         if (DE.isValidOffsetForDataOfSize(Offset, 4)) {
220           DebugName = DebugNameStr;
221           CRCHash = DE.getU32(&Offset);
222           return true;
223         }
224       }
225       break;
226     }
227   }
228   return false;
229 }
230 
darwinDsymMatchesBinary(const MachOObjectFile * DbgObj,const MachOObjectFile * Obj)231 bool darwinDsymMatchesBinary(const MachOObjectFile *DbgObj,
232                              const MachOObjectFile *Obj) {
233   ArrayRef<uint8_t> dbg_uuid = DbgObj->getUuid();
234   ArrayRef<uint8_t> bin_uuid = Obj->getUuid();
235   if (dbg_uuid.empty() || bin_uuid.empty())
236     return false;
237   return !memcmp(dbg_uuid.data(), bin_uuid.data(), dbg_uuid.size());
238 }
239 
240 } // end anonymous namespace
241 
lookUpDsymFile(const std::string & ExePath,const MachOObjectFile * MachExeObj,const std::string & ArchName)242 ObjectFile *LLVMSymbolizer::lookUpDsymFile(const std::string &ExePath,
243     const MachOObjectFile *MachExeObj, const std::string &ArchName) {
244   // On Darwin we may find DWARF in separate object file in
245   // resource directory.
246   std::vector<std::string> DsymPaths;
247   StringRef Filename = sys::path::filename(ExePath);
248   DsymPaths.push_back(getDarwinDWARFResourceForPath(ExePath, Filename));
249   for (const auto &Path : Opts.DsymHints) {
250     DsymPaths.push_back(getDarwinDWARFResourceForPath(Path, Filename));
251   }
252   for (const auto &Path : DsymPaths) {
253     auto DbgObjOrErr = getOrCreateObject(Path, ArchName);
254     if (!DbgObjOrErr) {
255       // Ignore errors, the file might not exist.
256       consumeError(DbgObjOrErr.takeError());
257       continue;
258     }
259     ObjectFile *DbgObj = DbgObjOrErr.get();
260     if (!DbgObj)
261       continue;
262     const MachOObjectFile *MachDbgObj = dyn_cast<const MachOObjectFile>(DbgObj);
263     if (!MachDbgObj)
264       continue;
265     if (darwinDsymMatchesBinary(MachDbgObj, MachExeObj))
266       return DbgObj;
267   }
268   return nullptr;
269 }
270 
lookUpDebuglinkObject(const std::string & Path,const ObjectFile * Obj,const std::string & ArchName)271 ObjectFile *LLVMSymbolizer::lookUpDebuglinkObject(const std::string &Path,
272                                                   const ObjectFile *Obj,
273                                                   const std::string &ArchName) {
274   std::string DebuglinkName;
275   uint32_t CRCHash;
276   std::string DebugBinaryPath;
277   if (!getGNUDebuglinkContents(Obj, DebuglinkName, CRCHash))
278     return nullptr;
279   if (!findDebugBinary(Path, DebuglinkName, CRCHash, DebugBinaryPath))
280     return nullptr;
281   auto DbgObjOrErr = getOrCreateObject(DebugBinaryPath, ArchName);
282   if (!DbgObjOrErr) {
283     // Ignore errors, the file might not exist.
284     consumeError(DbgObjOrErr.takeError());
285     return nullptr;
286   }
287   return DbgObjOrErr.get();
288 }
289 
290 Expected<LLVMSymbolizer::ObjectPair>
getOrCreateObjectPair(const std::string & Path,const std::string & ArchName)291 LLVMSymbolizer::getOrCreateObjectPair(const std::string &Path,
292                                       const std::string &ArchName) {
293   const auto &I = ObjectPairForPathArch.find(std::make_pair(Path, ArchName));
294   if (I != ObjectPairForPathArch.end()) {
295     return I->second;
296   }
297 
298   auto ObjOrErr = getOrCreateObject(Path, ArchName);
299   if (!ObjOrErr) {
300     ObjectPairForPathArch.insert(std::make_pair(std::make_pair(Path, ArchName),
301                                                 ObjectPair(nullptr, nullptr)));
302     return ObjOrErr.takeError();
303   }
304 
305   ObjectFile *Obj = ObjOrErr.get();
306   assert(Obj != nullptr);
307   ObjectFile *DbgObj = nullptr;
308 
309   if (auto MachObj = dyn_cast<const MachOObjectFile>(Obj))
310     DbgObj = lookUpDsymFile(Path, MachObj, ArchName);
311   if (!DbgObj)
312     DbgObj = lookUpDebuglinkObject(Path, Obj, ArchName);
313   if (!DbgObj)
314     DbgObj = Obj;
315   ObjectPair Res = std::make_pair(Obj, DbgObj);
316   ObjectPairForPathArch.insert(
317       std::make_pair(std::make_pair(Path, ArchName), Res));
318   return Res;
319 }
320 
321 Expected<ObjectFile *>
getOrCreateObject(const std::string & Path,const std::string & ArchName)322 LLVMSymbolizer::getOrCreateObject(const std::string &Path,
323                                   const std::string &ArchName) {
324   const auto &I = BinaryForPath.find(Path);
325   Binary *Bin = nullptr;
326   if (I == BinaryForPath.end()) {
327     Expected<OwningBinary<Binary>> BinOrErr = createBinary(Path);
328     if (!BinOrErr) {
329       BinaryForPath.insert(std::make_pair(Path, OwningBinary<Binary>()));
330       return BinOrErr.takeError();
331     }
332     Bin = BinOrErr->getBinary();
333     BinaryForPath.insert(std::make_pair(Path, std::move(BinOrErr.get())));
334   } else {
335     Bin = I->second.getBinary();
336   }
337 
338   if (!Bin)
339     return static_cast<ObjectFile *>(nullptr);
340 
341   if (MachOUniversalBinary *UB = dyn_cast_or_null<MachOUniversalBinary>(Bin)) {
342     const auto &I = ObjectForUBPathAndArch.find(std::make_pair(Path, ArchName));
343     if (I != ObjectForUBPathAndArch.end()) {
344       return I->second.get();
345     }
346     Expected<std::unique_ptr<ObjectFile>> ObjOrErr =
347         UB->getObjectForArch(ArchName);
348     if (!ObjOrErr) {
349       ObjectForUBPathAndArch.insert(std::make_pair(
350           std::make_pair(Path, ArchName), std::unique_ptr<ObjectFile>()));
351       return ObjOrErr.takeError();
352     }
353     ObjectFile *Res = ObjOrErr->get();
354     ObjectForUBPathAndArch.insert(std::make_pair(std::make_pair(Path, ArchName),
355                                                  std::move(ObjOrErr.get())));
356     return Res;
357   }
358   if (Bin->isObject()) {
359     return cast<ObjectFile>(Bin);
360   }
361   return errorCodeToError(object_error::arch_not_found);
362 }
363 
364 Expected<SymbolizableModule *>
getOrCreateModuleInfo(const std::string & ModuleName)365 LLVMSymbolizer::getOrCreateModuleInfo(const std::string &ModuleName) {
366   const auto &I = Modules.find(ModuleName);
367   if (I != Modules.end()) {
368     return I->second.get();
369   }
370   std::string BinaryName = ModuleName;
371   std::string ArchName = Opts.DefaultArch;
372   size_t ColonPos = ModuleName.find_last_of(':');
373   // Verify that substring after colon form a valid arch name.
374   if (ColonPos != std::string::npos) {
375     std::string ArchStr = ModuleName.substr(ColonPos + 1);
376     if (Triple(ArchStr).getArch() != Triple::UnknownArch) {
377       BinaryName = ModuleName.substr(0, ColonPos);
378       ArchName = ArchStr;
379     }
380   }
381   auto ObjectsOrErr = getOrCreateObjectPair(BinaryName, ArchName);
382   if (!ObjectsOrErr) {
383     // Failed to find valid object file.
384     Modules.insert(
385         std::make_pair(ModuleName, std::unique_ptr<SymbolizableModule>()));
386     return ObjectsOrErr.takeError();
387   }
388   ObjectPair Objects = ObjectsOrErr.get();
389 
390   std::unique_ptr<DIContext> Context;
391   // If this is a COFF object containing PDB info, use a PDBContext to
392   // symbolize. Otherwise, use DWARF.
393   if (auto CoffObject = dyn_cast<COFFObjectFile>(Objects.first)) {
394     const debug_pdb_info *PDBInfo;
395     StringRef PDBFileName;
396     auto EC = CoffObject->getDebugPDBInfo(PDBInfo, PDBFileName);
397     if (!EC && PDBInfo != nullptr) {
398       using namespace pdb;
399       std::unique_ptr<IPDBSession> Session;
400       if (auto Err = loadDataForEXE(PDB_ReaderType::DIA,
401                                     Objects.first->getFileName(), Session)) {
402         Modules.insert(
403             std::make_pair(ModuleName, std::unique_ptr<SymbolizableModule>()));
404         return std::move(Err);
405       }
406       Context.reset(new PDBContext(*CoffObject, std::move(Session)));
407     }
408   }
409   if (!Context)
410     Context.reset(new DWARFContextInMemory(*Objects.second));
411   assert(Context);
412   auto InfoOrErr =
413       SymbolizableObjectFile::create(Objects.first, std::move(Context));
414   std::unique_ptr<SymbolizableModule> SymMod;
415   if (InfoOrErr)
416     SymMod = std::move(InfoOrErr.get());
417   auto InsertResult =
418       Modules.insert(std::make_pair(ModuleName, std::move(SymMod)));
419   assert(InsertResult.second);
420   if (auto EC = InfoOrErr.getError())
421     return errorCodeToError(EC);
422   return InsertResult.first->second.get();
423 }
424 
425 namespace {
426 
427 // Undo these various manglings for Win32 extern "C" functions:
428 // cdecl       - _foo
429 // stdcall     - _foo@12
430 // fastcall    - @foo@12
431 // vectorcall  - foo@@12
432 // These are all different linkage names for 'foo'.
demanglePE32ExternCFunc(StringRef SymbolName)433 StringRef demanglePE32ExternCFunc(StringRef SymbolName) {
434   // Remove any '_' or '@' prefix.
435   char Front = SymbolName.empty() ? '\0' : SymbolName[0];
436   if (Front == '_' || Front == '@')
437     SymbolName = SymbolName.drop_front();
438 
439   // Remove any '@[0-9]+' suffix.
440   if (Front != '?') {
441     size_t AtPos = SymbolName.rfind('@');
442     if (AtPos != StringRef::npos &&
443         std::all_of(SymbolName.begin() + AtPos + 1, SymbolName.end(),
444                     [](char C) { return C >= '0' && C <= '9'; })) {
445       SymbolName = SymbolName.substr(0, AtPos);
446     }
447   }
448 
449   // Remove any ending '@' for vectorcall.
450   if (SymbolName.endswith("@"))
451     SymbolName = SymbolName.drop_back();
452 
453   return SymbolName;
454 }
455 
456 } // end anonymous namespace
457 
458 #if !defined(_MSC_VER)
459 // Assume that __cxa_demangle is provided by libcxxabi (except for Windows).
460 extern "C" char *__cxa_demangle(const char *mangled_name, char *output_buffer,
461                                 size_t *length, int *status);
462 #endif
463 
DemangleName(const std::string & Name,const SymbolizableModule * ModInfo)464 std::string LLVMSymbolizer::DemangleName(const std::string &Name,
465                                          const SymbolizableModule *ModInfo) {
466 #if !defined(_MSC_VER)
467   // We can spoil names of symbols with C linkage, so use an heuristic
468   // approach to check if the name should be demangled.
469   if (Name.substr(0, 2) == "_Z") {
470     int status = 0;
471     char *DemangledName = __cxa_demangle(Name.c_str(), nullptr, nullptr, &status);
472     if (status != 0)
473       return Name;
474     std::string Result = DemangledName;
475     free(DemangledName);
476     return Result;
477   }
478 #else
479   if (!Name.empty() && Name.front() == '?') {
480     // Only do MSVC C++ demangling on symbols starting with '?'.
481     char DemangledName[1024] = {0};
482     DWORD result = ::UnDecorateSymbolName(
483         Name.c_str(), DemangledName, 1023,
484         UNDNAME_NO_ACCESS_SPECIFIERS |       // Strip public, private, protected
485             UNDNAME_NO_ALLOCATION_LANGUAGE | // Strip __thiscall, __stdcall, etc
486             UNDNAME_NO_THROW_SIGNATURES |    // Strip throw() specifications
487             UNDNAME_NO_MEMBER_TYPE | // Strip virtual, static, etc specifiers
488             UNDNAME_NO_MS_KEYWORDS | // Strip all MS extension keywords
489             UNDNAME_NO_FUNCTION_RETURNS); // Strip function return types
490     return (result == 0) ? Name : std::string(DemangledName);
491   }
492 #endif
493   if (ModInfo && ModInfo->isWin32Module())
494     return std::string(demanglePE32ExternCFunc(Name));
495   return Name;
496 }
497 
498 } // namespace symbolize
499 } // namespace llvm
500