1 //===-- Symbol.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 "lldb/Symbol/Symbol.h" 10 11 #include "lldb/Core/Module.h" 12 #include "lldb/Core/ModuleSpec.h" 13 #include "lldb/Core/Section.h" 14 #include "lldb/Symbol/Function.h" 15 #include "lldb/Symbol/ObjectFile.h" 16 #include "lldb/Symbol/SymbolVendor.h" 17 #include "lldb/Symbol/Symtab.h" 18 #include "lldb/Target/Process.h" 19 #include "lldb/Target/Target.h" 20 #include "lldb/Utility/DataEncoder.h" 21 #include "lldb/Utility/Stream.h" 22 23 using namespace lldb; 24 using namespace lldb_private; 25 26 Symbol::Symbol() 27 : SymbolContextScope(), m_type_data_resolved(false), m_is_synthetic(false), 28 m_is_debug(false), m_is_external(false), m_size_is_sibling(false), 29 m_size_is_synthesized(false), m_size_is_valid(false), 30 m_demangled_is_synthesized(false), m_contains_linker_annotations(false), 31 m_is_weak(false), m_type(eSymbolTypeInvalid), m_mangled(), 32 m_addr_range() {} 33 34 Symbol::Symbol(uint32_t symID, llvm::StringRef name, SymbolType type, 35 bool external, bool is_debug, bool is_trampoline, 36 bool is_artificial, const lldb::SectionSP §ion_sp, 37 addr_t offset, addr_t size, bool size_is_valid, 38 bool contains_linker_annotations, uint32_t flags) 39 : SymbolContextScope(), m_uid(symID), m_type_data_resolved(false), 40 m_is_synthetic(is_artificial), m_is_debug(is_debug), 41 m_is_external(external), m_size_is_sibling(false), 42 m_size_is_synthesized(false), m_size_is_valid(size_is_valid || size > 0), 43 m_demangled_is_synthesized(false), 44 m_contains_linker_annotations(contains_linker_annotations), 45 m_is_weak(false), m_type(type), m_mangled(name), 46 m_addr_range(section_sp, offset, size), m_flags(flags) {} 47 48 Symbol::Symbol(uint32_t symID, const Mangled &mangled, SymbolType type, 49 bool external, bool is_debug, bool is_trampoline, 50 bool is_artificial, const AddressRange &range, 51 bool size_is_valid, bool contains_linker_annotations, 52 uint32_t flags) 53 : SymbolContextScope(), m_uid(symID), m_type_data_resolved(false), 54 m_is_synthetic(is_artificial), m_is_debug(is_debug), 55 m_is_external(external), m_size_is_sibling(false), 56 m_size_is_synthesized(false), 57 m_size_is_valid(size_is_valid || range.GetByteSize() > 0), 58 m_demangled_is_synthesized(false), 59 m_contains_linker_annotations(contains_linker_annotations), 60 m_is_weak(false), m_type(type), m_mangled(mangled), m_addr_range(range), 61 m_flags(flags) {} 62 63 Symbol::Symbol(const Symbol &rhs) 64 : SymbolContextScope(rhs), m_uid(rhs.m_uid), m_type_data(rhs.m_type_data), 65 m_type_data_resolved(rhs.m_type_data_resolved), 66 m_is_synthetic(rhs.m_is_synthetic), m_is_debug(rhs.m_is_debug), 67 m_is_external(rhs.m_is_external), 68 m_size_is_sibling(rhs.m_size_is_sibling), m_size_is_synthesized(false), 69 m_size_is_valid(rhs.m_size_is_valid), 70 m_demangled_is_synthesized(rhs.m_demangled_is_synthesized), 71 m_contains_linker_annotations(rhs.m_contains_linker_annotations), 72 m_is_weak(rhs.m_is_weak), m_type(rhs.m_type), m_mangled(rhs.m_mangled), 73 m_addr_range(rhs.m_addr_range), m_flags(rhs.m_flags) {} 74 75 const Symbol &Symbol::operator=(const Symbol &rhs) { 76 if (this != &rhs) { 77 SymbolContextScope::operator=(rhs); 78 m_uid = rhs.m_uid; 79 m_type_data = rhs.m_type_data; 80 m_type_data_resolved = rhs.m_type_data_resolved; 81 m_is_synthetic = rhs.m_is_synthetic; 82 m_is_debug = rhs.m_is_debug; 83 m_is_external = rhs.m_is_external; 84 m_size_is_sibling = rhs.m_size_is_sibling; 85 m_size_is_synthesized = rhs.m_size_is_sibling; 86 m_size_is_valid = rhs.m_size_is_valid; 87 m_demangled_is_synthesized = rhs.m_demangled_is_synthesized; 88 m_contains_linker_annotations = rhs.m_contains_linker_annotations; 89 m_is_weak = rhs.m_is_weak; 90 m_type = rhs.m_type; 91 m_mangled = rhs.m_mangled; 92 m_addr_range = rhs.m_addr_range; 93 m_flags = rhs.m_flags; 94 } 95 return *this; 96 } 97 98 void Symbol::Clear() { 99 m_uid = UINT32_MAX; 100 m_mangled.Clear(); 101 m_type_data = 0; 102 m_type_data_resolved = false; 103 m_is_synthetic = false; 104 m_is_debug = false; 105 m_is_external = false; 106 m_size_is_sibling = false; 107 m_size_is_synthesized = false; 108 m_size_is_valid = false; 109 m_demangled_is_synthesized = false; 110 m_contains_linker_annotations = false; 111 m_is_weak = false; 112 m_type = eSymbolTypeInvalid; 113 m_flags = 0; 114 m_addr_range.Clear(); 115 } 116 117 bool Symbol::ValueIsAddress() const { 118 return m_addr_range.GetBaseAddress().GetSection().get() != nullptr || 119 m_type == eSymbolTypeAbsolute; 120 } 121 122 ConstString Symbol::GetDisplayName() const { 123 return GetMangled().GetDisplayDemangledName(); 124 } 125 126 ConstString Symbol::GetReExportedSymbolName() const { 127 if (m_type == eSymbolTypeReExported) { 128 // For eSymbolTypeReExported, the "const char *" from a ConstString is used 129 // as the offset in the address range base address. We can then make this 130 // back into a string that is the re-exported name. 131 intptr_t str_ptr = m_addr_range.GetBaseAddress().GetOffset(); 132 if (str_ptr != 0) 133 return ConstString((const char *)str_ptr); 134 else 135 return GetName(); 136 } 137 return ConstString(); 138 } 139 140 FileSpec Symbol::GetReExportedSymbolSharedLibrary() const { 141 if (m_type == eSymbolTypeReExported) { 142 // For eSymbolTypeReExported, the "const char *" from a ConstString is used 143 // as the offset in the address range base address. We can then make this 144 // back into a string that is the re-exported name. 145 intptr_t str_ptr = m_addr_range.GetByteSize(); 146 if (str_ptr != 0) 147 return FileSpec((const char *)str_ptr); 148 } 149 return FileSpec(); 150 } 151 152 void Symbol::SetReExportedSymbolName(ConstString name) { 153 SetType(eSymbolTypeReExported); 154 // For eSymbolTypeReExported, the "const char *" from a ConstString is used 155 // as the offset in the address range base address. 156 m_addr_range.GetBaseAddress().SetOffset((uintptr_t)name.GetCString()); 157 } 158 159 bool Symbol::SetReExportedSymbolSharedLibrary(const FileSpec &fspec) { 160 if (m_type == eSymbolTypeReExported) { 161 // For eSymbolTypeReExported, the "const char *" from a ConstString is used 162 // as the offset in the address range base address. 163 m_addr_range.SetByteSize( 164 (uintptr_t)ConstString(fspec.GetPath().c_str()).GetCString()); 165 return true; 166 } 167 return false; 168 } 169 170 uint32_t Symbol::GetSiblingIndex() const { 171 return m_size_is_sibling ? m_addr_range.GetByteSize() : UINT32_MAX; 172 } 173 174 bool Symbol::IsTrampoline() const { return m_type == eSymbolTypeTrampoline; } 175 176 bool Symbol::IsIndirect() const { return m_type == eSymbolTypeResolver; } 177 178 void Symbol::GetDescription(Stream *s, lldb::DescriptionLevel level, 179 Target *target) const { 180 s->Printf("id = {0x%8.8x}", m_uid); 181 182 if (m_addr_range.GetBaseAddress().GetSection()) { 183 if (ValueIsAddress()) { 184 const lldb::addr_t byte_size = GetByteSize(); 185 if (byte_size > 0) { 186 s->PutCString(", range = "); 187 m_addr_range.Dump(s, target, Address::DumpStyleLoadAddress, 188 Address::DumpStyleFileAddress); 189 } else { 190 s->PutCString(", address = "); 191 m_addr_range.GetBaseAddress().Dump(s, target, 192 Address::DumpStyleLoadAddress, 193 Address::DumpStyleFileAddress); 194 } 195 } else 196 s->Printf(", value = 0x%16.16" PRIx64, 197 m_addr_range.GetBaseAddress().GetOffset()); 198 } else { 199 if (m_size_is_sibling) 200 s->Printf(", sibling = %5" PRIu64, 201 m_addr_range.GetBaseAddress().GetOffset()); 202 else 203 s->Printf(", value = 0x%16.16" PRIx64, 204 m_addr_range.GetBaseAddress().GetOffset()); 205 } 206 ConstString demangled = GetMangled().GetDemangledName(); 207 if (demangled) 208 s->Printf(", name=\"%s\"", demangled.AsCString()); 209 if (m_mangled.GetMangledName()) 210 s->Printf(", mangled=\"%s\"", m_mangled.GetMangledName().AsCString()); 211 } 212 213 void Symbol::Dump(Stream *s, Target *target, uint32_t index, 214 Mangled::NamePreference name_preference) const { 215 s->Printf("[%5u] %6u %c%c%c %-15s ", index, GetID(), m_is_debug ? 'D' : ' ', 216 m_is_synthetic ? 'S' : ' ', m_is_external ? 'X' : ' ', 217 GetTypeAsString()); 218 219 // Make sure the size of the symbol is up to date before dumping 220 GetByteSize(); 221 222 ConstString name = GetMangled().GetName(name_preference); 223 if (ValueIsAddress()) { 224 if (!m_addr_range.GetBaseAddress().Dump(s, nullptr, 225 Address::DumpStyleFileAddress)) 226 s->Printf("%*s", 18, ""); 227 228 s->PutChar(' '); 229 230 if (!m_addr_range.GetBaseAddress().Dump(s, target, 231 Address::DumpStyleLoadAddress)) 232 s->Printf("%*s", 18, ""); 233 234 const char *format = m_size_is_sibling ? " Sibling -> [%5llu] 0x%8.8x %s\n" 235 : " 0x%16.16" PRIx64 " 0x%8.8x %s\n"; 236 s->Printf(format, GetByteSize(), m_flags, name.AsCString("")); 237 } else if (m_type == eSymbolTypeReExported) { 238 s->Printf( 239 " 0x%8.8x %s", 240 m_flags, name.AsCString("")); 241 242 ConstString reexport_name = GetReExportedSymbolName(); 243 intptr_t shlib = m_addr_range.GetByteSize(); 244 if (shlib) 245 s->Printf(" -> %s`%s\n", (const char *)shlib, reexport_name.GetCString()); 246 else 247 s->Printf(" -> %s\n", reexport_name.GetCString()); 248 } else { 249 const char *format = 250 m_size_is_sibling 251 ? "0x%16.16" PRIx64 252 " Sibling -> [%5llu] 0x%8.8x %s\n" 253 : "0x%16.16" PRIx64 " 0x%16.16" PRIx64 254 " 0x%8.8x %s\n"; 255 s->Printf(format, m_addr_range.GetBaseAddress().GetOffset(), GetByteSize(), 256 m_flags, name.AsCString("")); 257 } 258 } 259 260 uint32_t Symbol::GetPrologueByteSize() { 261 if (m_type == eSymbolTypeCode || m_type == eSymbolTypeResolver) { 262 if (!m_type_data_resolved) { 263 m_type_data_resolved = true; 264 265 const Address &base_address = m_addr_range.GetBaseAddress(); 266 Function *function = base_address.CalculateSymbolContextFunction(); 267 if (function) { 268 // Functions have line entries which can also potentially have end of 269 // prologue information. So if this symbol points to a function, use 270 // the prologue information from there. 271 m_type_data = function->GetPrologueByteSize(); 272 } else { 273 ModuleSP module_sp(base_address.GetModule()); 274 SymbolContext sc; 275 if (module_sp) { 276 uint32_t resolved_flags = module_sp->ResolveSymbolContextForAddress( 277 base_address, eSymbolContextLineEntry, sc); 278 if (resolved_flags & eSymbolContextLineEntry) { 279 // Default to the end of the first line entry. 280 m_type_data = sc.line_entry.range.GetByteSize(); 281 282 // Set address for next line. 283 Address addr(base_address); 284 addr.Slide(m_type_data); 285 286 // Check the first few instructions and look for one that has a 287 // line number that is different than the first entry. This is also 288 // done in Function::GetPrologueByteSize(). 289 uint16_t total_offset = m_type_data; 290 for (int idx = 0; idx < 6; ++idx) { 291 SymbolContext sc_temp; 292 resolved_flags = module_sp->ResolveSymbolContextForAddress( 293 addr, eSymbolContextLineEntry, sc_temp); 294 // Make sure we got line number information... 295 if (!(resolved_flags & eSymbolContextLineEntry)) 296 break; 297 298 // If this line number is different than our first one, use it 299 // and we're done. 300 if (sc_temp.line_entry.line != sc.line_entry.line) { 301 m_type_data = total_offset; 302 break; 303 } 304 305 // Slide addr up to the next line address. 306 addr.Slide(sc_temp.line_entry.range.GetByteSize()); 307 total_offset += sc_temp.line_entry.range.GetByteSize(); 308 // If we've gone too far, bail out. 309 if (total_offset >= m_addr_range.GetByteSize()) 310 break; 311 } 312 313 // Sanity check - this may be a function in the middle of code that 314 // has debug information, but not for this symbol. So the line 315 // entries surrounding us won't lie inside our function. In that 316 // case, the line entry will be bigger than we are, so we do that 317 // quick check and if that is true, we just return 0. 318 if (m_type_data >= m_addr_range.GetByteSize()) 319 m_type_data = 0; 320 } else { 321 // TODO: expose something in Process to figure out the 322 // size of a function prologue. 323 m_type_data = 0; 324 } 325 } 326 } 327 } 328 return m_type_data; 329 } 330 return 0; 331 } 332 333 bool Symbol::Compare(ConstString name, SymbolType type) const { 334 if (type == eSymbolTypeAny || m_type == type) { 335 const Mangled &mangled = GetMangled(); 336 return mangled.GetMangledName() == name || 337 mangled.GetDemangledName() == name; 338 } 339 return false; 340 } 341 342 #define ENUM_TO_CSTRING(x) \ 343 case eSymbolType##x: \ 344 return #x; 345 346 const char *Symbol::GetTypeAsString() const { 347 switch (m_type) { 348 ENUM_TO_CSTRING(Invalid); 349 ENUM_TO_CSTRING(Absolute); 350 ENUM_TO_CSTRING(Code); 351 ENUM_TO_CSTRING(Resolver); 352 ENUM_TO_CSTRING(Data); 353 ENUM_TO_CSTRING(Trampoline); 354 ENUM_TO_CSTRING(Runtime); 355 ENUM_TO_CSTRING(Exception); 356 ENUM_TO_CSTRING(SourceFile); 357 ENUM_TO_CSTRING(HeaderFile); 358 ENUM_TO_CSTRING(ObjectFile); 359 ENUM_TO_CSTRING(CommonBlock); 360 ENUM_TO_CSTRING(Block); 361 ENUM_TO_CSTRING(Local); 362 ENUM_TO_CSTRING(Param); 363 ENUM_TO_CSTRING(Variable); 364 ENUM_TO_CSTRING(VariableType); 365 ENUM_TO_CSTRING(LineEntry); 366 ENUM_TO_CSTRING(LineHeader); 367 ENUM_TO_CSTRING(ScopeBegin); 368 ENUM_TO_CSTRING(ScopeEnd); 369 ENUM_TO_CSTRING(Additional); 370 ENUM_TO_CSTRING(Compiler); 371 ENUM_TO_CSTRING(Instrumentation); 372 ENUM_TO_CSTRING(Undefined); 373 ENUM_TO_CSTRING(ObjCClass); 374 ENUM_TO_CSTRING(ObjCMetaClass); 375 ENUM_TO_CSTRING(ObjCIVar); 376 ENUM_TO_CSTRING(ReExported); 377 default: 378 break; 379 } 380 return "<unknown SymbolType>"; 381 } 382 383 void Symbol::CalculateSymbolContext(SymbolContext *sc) { 384 // Symbols can reconstruct the symbol and the module in the symbol context 385 sc->symbol = this; 386 if (ValueIsAddress()) 387 sc->module_sp = GetAddressRef().GetModule(); 388 else 389 sc->module_sp.reset(); 390 } 391 392 ModuleSP Symbol::CalculateSymbolContextModule() { 393 if (ValueIsAddress()) 394 return GetAddressRef().GetModule(); 395 return ModuleSP(); 396 } 397 398 Symbol *Symbol::CalculateSymbolContextSymbol() { return this; } 399 400 void Symbol::DumpSymbolContext(Stream *s) { 401 bool dumped_module = false; 402 if (ValueIsAddress()) { 403 ModuleSP module_sp(GetAddressRef().GetModule()); 404 if (module_sp) { 405 dumped_module = true; 406 module_sp->DumpSymbolContext(s); 407 } 408 } 409 if (dumped_module) 410 s->PutCString(", "); 411 412 s->Printf("Symbol{0x%8.8x}", GetID()); 413 } 414 415 lldb::addr_t Symbol::GetByteSize() const { return m_addr_range.GetByteSize(); } 416 417 Symbol *Symbol::ResolveReExportedSymbolInModuleSpec( 418 Target &target, ConstString &reexport_name, ModuleSpec &module_spec, 419 ModuleList &seen_modules) const { 420 ModuleSP module_sp; 421 if (module_spec.GetFileSpec()) { 422 // Try searching for the module file spec first using the full path 423 module_sp = target.GetImages().FindFirstModule(module_spec); 424 if (!module_sp) { 425 // Next try and find the module by basename in case environment variables 426 // or other runtime trickery causes shared libraries to be loaded from 427 // alternate paths 428 module_spec.GetFileSpec().GetDirectory().Clear(); 429 module_sp = target.GetImages().FindFirstModule(module_spec); 430 } 431 } 432 433 if (module_sp) { 434 // There should not be cycles in the reexport list, but we don't want to 435 // crash if there are so make sure we haven't seen this before: 436 if (!seen_modules.AppendIfNeeded(module_sp)) 437 return nullptr; 438 439 lldb_private::SymbolContextList sc_list; 440 module_sp->FindSymbolsWithNameAndType(reexport_name, eSymbolTypeAny, 441 sc_list); 442 const size_t num_scs = sc_list.GetSize(); 443 if (num_scs > 0) { 444 for (size_t i = 0; i < num_scs; ++i) { 445 lldb_private::SymbolContext sc; 446 if (sc_list.GetContextAtIndex(i, sc)) { 447 if (sc.symbol->IsExternal()) 448 return sc.symbol; 449 } 450 } 451 } 452 // If we didn't find the symbol in this module, it may be because this 453 // module re-exports some whole other library. We have to search those as 454 // well: 455 seen_modules.Append(module_sp); 456 457 FileSpecList reexported_libraries = 458 module_sp->GetObjectFile()->GetReExportedLibraries(); 459 size_t num_reexported_libraries = reexported_libraries.GetSize(); 460 for (size_t idx = 0; idx < num_reexported_libraries; idx++) { 461 ModuleSpec reexported_module_spec; 462 reexported_module_spec.GetFileSpec() = 463 reexported_libraries.GetFileSpecAtIndex(idx); 464 Symbol *result_symbol = ResolveReExportedSymbolInModuleSpec( 465 target, reexport_name, reexported_module_spec, seen_modules); 466 if (result_symbol) 467 return result_symbol; 468 } 469 } 470 return nullptr; 471 } 472 473 Symbol *Symbol::ResolveReExportedSymbol(Target &target) const { 474 ConstString reexport_name(GetReExportedSymbolName()); 475 if (reexport_name) { 476 ModuleSpec module_spec; 477 ModuleList seen_modules; 478 module_spec.GetFileSpec() = GetReExportedSymbolSharedLibrary(); 479 if (module_spec.GetFileSpec()) { 480 return ResolveReExportedSymbolInModuleSpec(target, reexport_name, 481 module_spec, seen_modules); 482 } 483 } 484 return nullptr; 485 } 486 487 lldb::addr_t Symbol::GetFileAddress() const { 488 if (ValueIsAddress()) 489 return GetAddressRef().GetFileAddress(); 490 else 491 return LLDB_INVALID_ADDRESS; 492 } 493 494 lldb::addr_t Symbol::GetLoadAddress(Target *target) const { 495 if (ValueIsAddress()) 496 return GetAddressRef().GetLoadAddress(target); 497 else 498 return LLDB_INVALID_ADDRESS; 499 } 500 501 ConstString Symbol::GetName() const { return GetMangled().GetName(); } 502 503 ConstString Symbol::GetNameNoArguments() const { 504 return GetMangled().GetName(Mangled::ePreferDemangledWithoutArguments); 505 } 506 507 lldb::addr_t Symbol::ResolveCallableAddress(Target &target) const { 508 if (GetType() == lldb::eSymbolTypeUndefined) 509 return LLDB_INVALID_ADDRESS; 510 511 Address func_so_addr; 512 513 bool is_indirect = IsIndirect(); 514 if (GetType() == eSymbolTypeReExported) { 515 Symbol *reexported_symbol = ResolveReExportedSymbol(target); 516 if (reexported_symbol) { 517 func_so_addr = reexported_symbol->GetAddress(); 518 is_indirect = reexported_symbol->IsIndirect(); 519 } 520 } else { 521 func_so_addr = GetAddress(); 522 is_indirect = IsIndirect(); 523 } 524 525 if (func_so_addr.IsValid()) { 526 if (!target.GetProcessSP() && is_indirect) { 527 // can't resolve indirect symbols without calling a function... 528 return LLDB_INVALID_ADDRESS; 529 } 530 531 lldb::addr_t load_addr = 532 func_so_addr.GetCallableLoadAddress(&target, is_indirect); 533 534 if (load_addr != LLDB_INVALID_ADDRESS) { 535 return load_addr; 536 } 537 } 538 539 return LLDB_INVALID_ADDRESS; 540 } 541 542 lldb::DisassemblerSP Symbol::GetInstructions(const ExecutionContext &exe_ctx, 543 const char *flavor, 544 bool prefer_file_cache) { 545 ModuleSP module_sp(m_addr_range.GetBaseAddress().GetModule()); 546 if (module_sp && exe_ctx.HasTargetScope()) { 547 return Disassembler::DisassembleRange(module_sp->GetArchitecture(), nullptr, 548 flavor, exe_ctx.GetTargetRef(), 549 m_addr_range, !prefer_file_cache); 550 } 551 return lldb::DisassemblerSP(); 552 } 553 554 bool Symbol::GetDisassembly(const ExecutionContext &exe_ctx, const char *flavor, 555 bool prefer_file_cache, Stream &strm) { 556 lldb::DisassemblerSP disassembler_sp = 557 GetInstructions(exe_ctx, flavor, prefer_file_cache); 558 if (disassembler_sp) { 559 const bool show_address = true; 560 const bool show_bytes = false; 561 const bool show_control_flow_kind = false; 562 disassembler_sp->GetInstructionList().Dump( 563 &strm, show_address, show_bytes, show_control_flow_kind, &exe_ctx); 564 return true; 565 } 566 return false; 567 } 568 569 bool Symbol::ContainsFileAddress(lldb::addr_t file_addr) const { 570 return m_addr_range.ContainsFileAddress(file_addr); 571 } 572 573 bool Symbol::IsSyntheticWithAutoGeneratedName() const { 574 if (!IsSynthetic()) 575 return false; 576 if (!m_mangled) 577 return true; 578 ConstString demangled = m_mangled.GetDemangledName(); 579 return demangled.GetStringRef().startswith(GetSyntheticSymbolPrefix()); 580 } 581 582 void Symbol::SynthesizeNameIfNeeded() const { 583 if (m_is_synthetic && !m_mangled) { 584 // Synthetic symbol names don't mean anything, but they do uniquely 585 // identify individual symbols so we give them a unique name. The name 586 // starts with the synthetic symbol prefix, followed by a unique number. 587 // Typically the UserID of a real symbol is the symbol table index of the 588 // symbol in the object file's symbol table(s), so it will be the same 589 // every time you read in the object file. We want the same persistence for 590 // synthetic symbols so that users can identify them across multiple debug 591 // sessions, to understand crashes in those symbols and to reliably set 592 // breakpoints on them. 593 llvm::SmallString<256> name; 594 llvm::raw_svector_ostream os(name); 595 os << GetSyntheticSymbolPrefix() << GetID(); 596 m_mangled.SetDemangledName(ConstString(os.str())); 597 } 598 } 599 600 bool Symbol::Decode(const DataExtractor &data, lldb::offset_t *offset_ptr, 601 const SectionList *section_list, 602 const StringTableReader &strtab) { 603 if (!data.ValidOffsetForDataOfSize(*offset_ptr, 8)) 604 return false; 605 m_uid = data.GetU32(offset_ptr); 606 m_type_data = data.GetU16(offset_ptr); 607 const uint16_t bitfields = data.GetU16(offset_ptr); 608 m_type_data_resolved = (1u << 15 & bitfields) != 0; 609 m_is_synthetic = (1u << 14 & bitfields) != 0; 610 m_is_debug = (1u << 13 & bitfields) != 0; 611 m_is_external = (1u << 12 & bitfields) != 0; 612 m_size_is_sibling = (1u << 11 & bitfields) != 0; 613 m_size_is_synthesized = (1u << 10 & bitfields) != 0; 614 m_size_is_valid = (1u << 9 & bitfields) != 0; 615 m_demangled_is_synthesized = (1u << 8 & bitfields) != 0; 616 m_contains_linker_annotations = (1u << 7 & bitfields) != 0; 617 m_is_weak = (1u << 6 & bitfields) != 0; 618 m_type = bitfields & 0x003f; 619 if (!m_mangled.Decode(data, offset_ptr, strtab)) 620 return false; 621 if (!data.ValidOffsetForDataOfSize(*offset_ptr, 20)) 622 return false; 623 const bool is_addr = data.GetU8(offset_ptr) != 0; 624 const uint64_t value = data.GetU64(offset_ptr); 625 if (is_addr) { 626 m_addr_range.GetBaseAddress().ResolveAddressUsingFileSections( 627 value, section_list); 628 } else { 629 m_addr_range.GetBaseAddress().Clear(); 630 m_addr_range.GetBaseAddress().SetOffset(value); 631 } 632 m_addr_range.SetByteSize(data.GetU64(offset_ptr)); 633 m_flags = data.GetU32(offset_ptr); 634 return true; 635 } 636 637 /// The encoding format for the symbol is as follows: 638 /// 639 /// uint32_t m_uid; 640 /// uint16_t m_type_data; 641 /// uint16_t bitfield_data; 642 /// Mangled mangled; 643 /// uint8_t is_addr; 644 /// uint64_t file_addr_or_value; 645 /// uint64_t size; 646 /// uint32_t flags; 647 /// 648 /// The only tricky thing in this encoding is encoding all of the bits in the 649 /// bitfields. We use a trick to store all bitfields as a 16 bit value and we 650 /// do the same thing when decoding the symbol. There are test that ensure this 651 /// encoding works for each individual bit. Everything else is very easy to 652 /// store. 653 void Symbol::Encode(DataEncoder &file, ConstStringTable &strtab) const { 654 file.AppendU32(m_uid); 655 file.AppendU16(m_type_data); 656 uint16_t bitfields = m_type; 657 if (m_type_data_resolved) 658 bitfields |= 1u << 15; 659 if (m_is_synthetic) 660 bitfields |= 1u << 14; 661 if (m_is_debug) 662 bitfields |= 1u << 13; 663 if (m_is_external) 664 bitfields |= 1u << 12; 665 if (m_size_is_sibling) 666 bitfields |= 1u << 11; 667 if (m_size_is_synthesized) 668 bitfields |= 1u << 10; 669 if (m_size_is_valid) 670 bitfields |= 1u << 9; 671 if (m_demangled_is_synthesized) 672 bitfields |= 1u << 8; 673 if (m_contains_linker_annotations) 674 bitfields |= 1u << 7; 675 if (m_is_weak) 676 bitfields |= 1u << 6; 677 file.AppendU16(bitfields); 678 m_mangled.Encode(file, strtab); 679 // A symbol's value might be an address, or it might be a constant. If the 680 // symbol's base address doesn't have a section, then it is a constant value. 681 // If it does have a section, we will encode the file address and re-resolve 682 // the address when we decode it. 683 bool is_addr = m_addr_range.GetBaseAddress().GetSection().get() != nullptr; 684 file.AppendU8(is_addr); 685 file.AppendU64(m_addr_range.GetBaseAddress().GetFileAddress()); 686 file.AppendU64(m_addr_range.GetByteSize()); 687 file.AppendU32(m_flags); 688 } 689 690 bool Symbol::operator==(const Symbol &rhs) const { 691 if (m_uid != rhs.m_uid) 692 return false; 693 if (m_type_data != rhs.m_type_data) 694 return false; 695 if (m_type_data_resolved != rhs.m_type_data_resolved) 696 return false; 697 if (m_is_synthetic != rhs.m_is_synthetic) 698 return false; 699 if (m_is_debug != rhs.m_is_debug) 700 return false; 701 if (m_is_external != rhs.m_is_external) 702 return false; 703 if (m_size_is_sibling != rhs.m_size_is_sibling) 704 return false; 705 if (m_size_is_synthesized != rhs.m_size_is_synthesized) 706 return false; 707 if (m_size_is_valid != rhs.m_size_is_valid) 708 return false; 709 if (m_demangled_is_synthesized != rhs.m_demangled_is_synthesized) 710 return false; 711 if (m_contains_linker_annotations != rhs.m_contains_linker_annotations) 712 return false; 713 if (m_is_weak != rhs.m_is_weak) 714 return false; 715 if (m_type != rhs.m_type) 716 return false; 717 if (m_mangled != rhs.m_mangled) 718 return false; 719 if (m_addr_range.GetBaseAddress() != rhs.m_addr_range.GetBaseAddress()) 720 return false; 721 if (m_addr_range.GetByteSize() != rhs.m_addr_range.GetByteSize()) 722 return false; 723 if (m_flags != rhs.m_flags) 724 return false; 725 return true; 726 } 727