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