1 //===-- ItaniumABILanguageRuntime.cpp --------------------------------------*- 2 //C++ -*-===// 3 // 4 // The LLVM Compiler Infrastructure 5 // 6 // This file is distributed under the University of Illinois Open Source 7 // License. See LICENSE.TXT for details. 8 // 9 //===----------------------------------------------------------------------===// 10 11 #include "ItaniumABILanguageRuntime.h" 12 13 #include "lldb/Breakpoint/BreakpointLocation.h" 14 #include "lldb/Core/Mangled.h" 15 #include "lldb/Core/Module.h" 16 #include "lldb/Core/PluginManager.h" 17 #include "lldb/Core/Scalar.h" 18 #include "lldb/Core/ValueObject.h" 19 #include "lldb/Core/ValueObjectMemory.h" 20 #include "lldb/Interpreter/CommandObject.h" 21 #include "lldb/Interpreter/CommandObjectMultiword.h" 22 #include "lldb/Interpreter/CommandReturnObject.h" 23 #include "lldb/Symbol/ClangASTContext.h" 24 #include "lldb/Symbol/Symbol.h" 25 #include "lldb/Symbol/SymbolFile.h" 26 #include "lldb/Symbol/TypeList.h" 27 #include "lldb/Target/Process.h" 28 #include "lldb/Target/RegisterContext.h" 29 #include "lldb/Target/SectionLoadList.h" 30 #include "lldb/Target/StopInfo.h" 31 #include "lldb/Target/Target.h" 32 #include "lldb/Target/Thread.h" 33 #include "lldb/Utility/ConstString.h" 34 #include "lldb/Utility/Log.h" 35 #include "lldb/Utility/Status.h" 36 37 #include <vector> 38 39 using namespace lldb; 40 using namespace lldb_private; 41 42 static const char *vtable_demangled_prefix = "vtable for "; 43 44 bool ItaniumABILanguageRuntime::CouldHaveDynamicValue(ValueObject &in_value) { 45 const bool check_cxx = true; 46 const bool check_objc = false; 47 return in_value.GetCompilerType().IsPossibleDynamicType(NULL, check_cxx, 48 check_objc); 49 } 50 51 TypeAndOrName ItaniumABILanguageRuntime::GetTypeInfoFromVTableAddress( 52 ValueObject &in_value, lldb::addr_t original_ptr, 53 lldb::addr_t vtable_load_addr) { 54 if (m_process && vtable_load_addr != LLDB_INVALID_ADDRESS) { 55 // Find the symbol that contains the "vtable_load_addr" address 56 Address vtable_addr; 57 Target &target = m_process->GetTarget(); 58 if (!target.GetSectionLoadList().IsEmpty()) { 59 if (target.GetSectionLoadList().ResolveLoadAddress(vtable_load_addr, 60 vtable_addr)) { 61 // See if we have cached info for this type already 62 TypeAndOrName type_info = GetDynamicTypeInfo(vtable_addr); 63 if (type_info) 64 return type_info; 65 66 SymbolContext sc; 67 target.GetImages().ResolveSymbolContextForAddress( 68 vtable_addr, eSymbolContextSymbol, sc); 69 Symbol *symbol = sc.symbol; 70 if (symbol != NULL) { 71 const char *name = 72 symbol->GetMangled() 73 .GetDemangledName(lldb::eLanguageTypeC_plus_plus) 74 .AsCString(); 75 if (name && strstr(name, vtable_demangled_prefix) == name) { 76 Log *log( 77 lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_OBJECT)); 78 if (log) 79 log->Printf("0x%16.16" PRIx64 80 ": static-type = '%s' has vtable symbol '%s'\n", 81 original_ptr, in_value.GetTypeName().GetCString(), 82 name); 83 // We are a C++ class, that's good. Get the class name and look it 84 // up: 85 const char *class_name = name + strlen(vtable_demangled_prefix); 86 // We know the class name is absolute, so tell FindTypes that by 87 // prefixing it with the root namespace: 88 std::string lookup_name("::"); 89 lookup_name.append(class_name); 90 91 type_info.SetName(class_name); 92 const bool exact_match = true; 93 TypeList class_types; 94 95 uint32_t num_matches = 0; 96 // First look in the module that the vtable symbol came from and 97 // look for a single exact match. 98 llvm::DenseSet<SymbolFile *> searched_symbol_files; 99 if (sc.module_sp) { 100 num_matches = sc.module_sp->FindTypes( 101 sc, ConstString(lookup_name), exact_match, 1, 102 searched_symbol_files, class_types); 103 } 104 105 // If we didn't find a symbol, then move on to the entire module 106 // list in the target and get as many unique matches as possible 107 if (num_matches == 0) { 108 num_matches = target.GetImages().FindTypes( 109 sc, ConstString(lookup_name), exact_match, UINT32_MAX, 110 searched_symbol_files, class_types); 111 } 112 113 lldb::TypeSP type_sp; 114 if (num_matches == 0) { 115 if (log) 116 log->Printf("0x%16.16" PRIx64 ": is not dynamic\n", 117 original_ptr); 118 return TypeAndOrName(); 119 } 120 if (num_matches == 1) { 121 type_sp = class_types.GetTypeAtIndex(0); 122 if (type_sp) { 123 if (ClangASTContext::IsCXXClassType( 124 type_sp->GetForwardCompilerType())) { 125 if (log) 126 log->Printf( 127 "0x%16.16" PRIx64 128 ": static-type = '%s' has dynamic type: uid={0x%" PRIx64 129 "}, type-name='%s'\n", 130 original_ptr, in_value.GetTypeName().AsCString(), 131 type_sp->GetID(), type_sp->GetName().GetCString()); 132 type_info.SetTypeSP(type_sp); 133 } 134 } 135 } else if (num_matches > 1) { 136 size_t i; 137 if (log) { 138 for (i = 0; i < num_matches; i++) { 139 type_sp = class_types.GetTypeAtIndex(i); 140 if (type_sp) { 141 if (log) 142 log->Printf( 143 "0x%16.16" PRIx64 144 ": static-type = '%s' has multiple matching dynamic " 145 "types: uid={0x%" PRIx64 "}, type-name='%s'\n", 146 original_ptr, in_value.GetTypeName().AsCString(), 147 type_sp->GetID(), type_sp->GetName().GetCString()); 148 } 149 } 150 } 151 152 for (i = 0; i < num_matches; i++) { 153 type_sp = class_types.GetTypeAtIndex(i); 154 if (type_sp) { 155 if (ClangASTContext::IsCXXClassType( 156 type_sp->GetForwardCompilerType())) { 157 if (log) 158 log->Printf( 159 "0x%16.16" PRIx64 ": static-type = '%s' has multiple " 160 "matching dynamic types, picking " 161 "this one: uid={0x%" PRIx64 162 "}, type-name='%s'\n", 163 original_ptr, in_value.GetTypeName().AsCString(), 164 type_sp->GetID(), type_sp->GetName().GetCString()); 165 type_info.SetTypeSP(type_sp); 166 } 167 } 168 } 169 170 if (log && i == num_matches) { 171 log->Printf( 172 "0x%16.16" PRIx64 173 ": static-type = '%s' has multiple matching dynamic " 174 "types, didn't find a C++ match\n", 175 original_ptr, in_value.GetTypeName().AsCString()); 176 } 177 } 178 if (type_info) 179 SetDynamicTypeInfo(vtable_addr, type_info); 180 return type_info; 181 } 182 } 183 } 184 } 185 } 186 return TypeAndOrName(); 187 } 188 189 bool ItaniumABILanguageRuntime::GetDynamicTypeAndAddress( 190 ValueObject &in_value, lldb::DynamicValueType use_dynamic, 191 TypeAndOrName &class_type_or_name, Address &dynamic_address, 192 Value::ValueType &value_type) { 193 // For Itanium, if the type has a vtable pointer in the object, it will be at 194 // offset 0 in the object. That will point to the "address point" within the 195 // vtable (not the beginning of the vtable.) We can then look up the symbol 196 // containing this "address point" and that symbol's name demangled will 197 // contain the full class name. The second pointer above the "address point" 198 // is the "offset_to_top". We'll use that to get the start of the value 199 // object which holds the dynamic type. 200 // 201 202 class_type_or_name.Clear(); 203 value_type = Value::ValueType::eValueTypeScalar; 204 205 // Only a pointer or reference type can have a different dynamic and static 206 // type: 207 if (CouldHaveDynamicValue(in_value)) { 208 // First job, pull out the address at 0 offset from the object. 209 AddressType address_type; 210 lldb::addr_t original_ptr = in_value.GetPointerValue(&address_type); 211 if (original_ptr == LLDB_INVALID_ADDRESS) 212 return false; 213 214 ExecutionContext exe_ctx(in_value.GetExecutionContextRef()); 215 216 Process *process = exe_ctx.GetProcessPtr(); 217 218 if (process == nullptr) 219 return false; 220 221 Status error; 222 const lldb::addr_t vtable_address_point = 223 process->ReadPointerFromMemory(original_ptr, error); 224 225 if (!error.Success() || vtable_address_point == LLDB_INVALID_ADDRESS) { 226 return false; 227 } 228 229 class_type_or_name = GetTypeInfoFromVTableAddress(in_value, original_ptr, 230 vtable_address_point); 231 232 if (class_type_or_name) { 233 TypeSP type_sp = class_type_or_name.GetTypeSP(); 234 // There can only be one type with a given name, so we've just found 235 // duplicate definitions, and this one will do as well as any other. We 236 // don't consider something to have a dynamic type if it is the same as 237 // the static type. So compare against the value we were handed. 238 if (type_sp) { 239 if (ClangASTContext::AreTypesSame(in_value.GetCompilerType(), 240 type_sp->GetForwardCompilerType())) { 241 // The dynamic type we found was the same type, so we don't have a 242 // dynamic type here... 243 return false; 244 } 245 246 // The offset_to_top is two pointers above the vtable pointer. 247 const uint32_t addr_byte_size = process->GetAddressByteSize(); 248 const lldb::addr_t offset_to_top_location = 249 vtable_address_point - 2 * addr_byte_size; 250 // Watch for underflow, offset_to_top_location should be less than 251 // vtable_address_point 252 if (offset_to_top_location >= vtable_address_point) 253 return false; 254 const int64_t offset_to_top = process->ReadSignedIntegerFromMemory( 255 offset_to_top_location, addr_byte_size, INT64_MIN, error); 256 257 if (offset_to_top == INT64_MIN) 258 return false; 259 // So the dynamic type is a value that starts at offset_to_top above 260 // the original address. 261 lldb::addr_t dynamic_addr = original_ptr + offset_to_top; 262 if (!process->GetTarget().GetSectionLoadList().ResolveLoadAddress( 263 dynamic_addr, dynamic_address)) { 264 dynamic_address.SetRawAddress(dynamic_addr); 265 } 266 return true; 267 } 268 } 269 } 270 271 return class_type_or_name.IsEmpty() == false; 272 } 273 274 TypeAndOrName ItaniumABILanguageRuntime::FixUpDynamicType( 275 const TypeAndOrName &type_and_or_name, ValueObject &static_value) { 276 CompilerType static_type(static_value.GetCompilerType()); 277 Flags static_type_flags(static_type.GetTypeInfo()); 278 279 TypeAndOrName ret(type_and_or_name); 280 if (type_and_or_name.HasType()) { 281 // The type will always be the type of the dynamic object. If our parent's 282 // type was a pointer, then our type should be a pointer to the type of the 283 // dynamic object. If a reference, then the original type should be 284 // okay... 285 CompilerType orig_type = type_and_or_name.GetCompilerType(); 286 CompilerType corrected_type = orig_type; 287 if (static_type_flags.AllSet(eTypeIsPointer)) 288 corrected_type = orig_type.GetPointerType(); 289 else if (static_type_flags.AllSet(eTypeIsReference)) 290 corrected_type = orig_type.GetLValueReferenceType(); 291 ret.SetCompilerType(corrected_type); 292 } else { 293 // If we are here we need to adjust our dynamic type name to include the 294 // correct & or * symbol 295 std::string corrected_name(type_and_or_name.GetName().GetCString()); 296 if (static_type_flags.AllSet(eTypeIsPointer)) 297 corrected_name.append(" *"); 298 else if (static_type_flags.AllSet(eTypeIsReference)) 299 corrected_name.append(" &"); 300 // the parent type should be a correctly pointer'ed or referenc'ed type 301 ret.SetCompilerType(static_type); 302 ret.SetName(corrected_name.c_str()); 303 } 304 return ret; 305 } 306 307 bool ItaniumABILanguageRuntime::IsVTableName(const char *name) { 308 if (name == NULL) 309 return false; 310 311 // Can we maybe ask Clang about this? 312 if (strstr(name, "_vptr$") == name) 313 return true; 314 else 315 return false; 316 } 317 318 //------------------------------------------------------------------ 319 // Static Functions 320 //------------------------------------------------------------------ 321 LanguageRuntime * 322 ItaniumABILanguageRuntime::CreateInstance(Process *process, 323 lldb::LanguageType language) { 324 // FIXME: We have to check the process and make sure we actually know that 325 // this process supports 326 // the Itanium ABI. 327 if (language == eLanguageTypeC_plus_plus || 328 language == eLanguageTypeC_plus_plus_03 || 329 language == eLanguageTypeC_plus_plus_11 || 330 language == eLanguageTypeC_plus_plus_14) 331 return new ItaniumABILanguageRuntime(process); 332 else 333 return NULL; 334 } 335 336 class CommandObjectMultiwordItaniumABI_Demangle : public CommandObjectParsed { 337 public: 338 CommandObjectMultiwordItaniumABI_Demangle(CommandInterpreter &interpreter) 339 : CommandObjectParsed(interpreter, "demangle", 340 "Demangle a C++ mangled name.", 341 "language cplusplus demangle") { 342 CommandArgumentEntry arg; 343 CommandArgumentData index_arg; 344 345 // Define the first (and only) variant of this arg. 346 index_arg.arg_type = eArgTypeSymbol; 347 index_arg.arg_repetition = eArgRepeatPlus; 348 349 // There is only one variant this argument could be; put it into the 350 // argument entry. 351 arg.push_back(index_arg); 352 353 // Push the data for the first argument into the m_arguments vector. 354 m_arguments.push_back(arg); 355 } 356 357 ~CommandObjectMultiwordItaniumABI_Demangle() override = default; 358 359 protected: 360 bool DoExecute(Args &command, CommandReturnObject &result) override { 361 bool demangled_any = false; 362 bool error_any = false; 363 for (auto &entry : command.entries()) { 364 if (entry.ref.empty()) 365 continue; 366 367 // the actual Mangled class should be strict about this, but on the 368 // command line if you're copying mangled names out of 'nm' on Darwin, 369 // they will come out with an extra underscore - be willing to strip this 370 // on behalf of the user. This is the moral equivalent of the -_/-n 371 // options to c++filt 372 auto name = entry.ref; 373 if (name.startswith("__Z")) 374 name = name.drop_front(); 375 376 Mangled mangled(name, true); 377 if (mangled.GuessLanguage() == lldb::eLanguageTypeC_plus_plus) { 378 ConstString demangled( 379 mangled.GetDisplayDemangledName(lldb::eLanguageTypeC_plus_plus)); 380 demangled_any = true; 381 result.AppendMessageWithFormat("%s ---> %s\n", entry.ref.str().c_str(), 382 demangled.GetCString()); 383 } else { 384 error_any = true; 385 result.AppendErrorWithFormat("%s is not a valid C++ mangled name\n", 386 entry.ref.str().c_str()); 387 } 388 } 389 390 result.SetStatus( 391 error_any ? lldb::eReturnStatusFailed 392 : (demangled_any ? lldb::eReturnStatusSuccessFinishResult 393 : lldb::eReturnStatusSuccessFinishNoResult)); 394 return result.Succeeded(); 395 } 396 }; 397 398 class CommandObjectMultiwordItaniumABI : public CommandObjectMultiword { 399 public: 400 CommandObjectMultiwordItaniumABI(CommandInterpreter &interpreter) 401 : CommandObjectMultiword( 402 interpreter, "cplusplus", 403 "Commands for operating on the C++ language runtime.", 404 "cplusplus <subcommand> [<subcommand-options>]") { 405 LoadSubCommand( 406 "demangle", 407 CommandObjectSP( 408 new CommandObjectMultiwordItaniumABI_Demangle(interpreter))); 409 } 410 411 ~CommandObjectMultiwordItaniumABI() override = default; 412 }; 413 414 void ItaniumABILanguageRuntime::Initialize() { 415 PluginManager::RegisterPlugin( 416 GetPluginNameStatic(), "Itanium ABI for the C++ language", CreateInstance, 417 [](CommandInterpreter &interpreter) -> lldb::CommandObjectSP { 418 return CommandObjectSP( 419 new CommandObjectMultiwordItaniumABI(interpreter)); 420 }); 421 } 422 423 void ItaniumABILanguageRuntime::Terminate() { 424 PluginManager::UnregisterPlugin(CreateInstance); 425 } 426 427 lldb_private::ConstString ItaniumABILanguageRuntime::GetPluginNameStatic() { 428 static ConstString g_name("itanium"); 429 return g_name; 430 } 431 432 //------------------------------------------------------------------ 433 // PluginInterface protocol 434 //------------------------------------------------------------------ 435 lldb_private::ConstString ItaniumABILanguageRuntime::GetPluginName() { 436 return GetPluginNameStatic(); 437 } 438 439 uint32_t ItaniumABILanguageRuntime::GetPluginVersion() { return 1; } 440 441 BreakpointResolverSP ItaniumABILanguageRuntime::CreateExceptionResolver( 442 Breakpoint *bkpt, bool catch_bp, bool throw_bp) { 443 return CreateExceptionResolver(bkpt, catch_bp, throw_bp, false); 444 } 445 446 BreakpointResolverSP ItaniumABILanguageRuntime::CreateExceptionResolver( 447 Breakpoint *bkpt, bool catch_bp, bool throw_bp, bool for_expressions) { 448 // One complication here is that most users DON'T want to stop at 449 // __cxa_allocate_expression, but until we can do anything better with 450 // predicting unwinding the expression parser does. So we have two forms of 451 // the exception breakpoints, one for expressions that leaves out 452 // __cxa_allocate_exception, and one that includes it. The 453 // SetExceptionBreakpoints does the latter, the CreateExceptionBreakpoint in 454 // the runtime the former. 455 static const char *g_catch_name = "__cxa_begin_catch"; 456 static const char *g_throw_name1 = "__cxa_throw"; 457 static const char *g_throw_name2 = "__cxa_rethrow"; 458 static const char *g_exception_throw_name = "__cxa_allocate_exception"; 459 std::vector<const char *> exception_names; 460 exception_names.reserve(4); 461 if (catch_bp) 462 exception_names.push_back(g_catch_name); 463 464 if (throw_bp) { 465 exception_names.push_back(g_throw_name1); 466 exception_names.push_back(g_throw_name2); 467 } 468 469 if (for_expressions) 470 exception_names.push_back(g_exception_throw_name); 471 472 BreakpointResolverSP resolver_sp(new BreakpointResolverName( 473 bkpt, exception_names.data(), exception_names.size(), 474 eFunctionNameTypeBase, eLanguageTypeUnknown, 0, eLazyBoolNo)); 475 476 return resolver_sp; 477 } 478 479 lldb::SearchFilterSP ItaniumABILanguageRuntime::CreateExceptionSearchFilter() { 480 Target &target = m_process->GetTarget(); 481 482 if (target.GetArchitecture().GetTriple().getVendor() == llvm::Triple::Apple) { 483 // Limit the number of modules that are searched for these breakpoints for 484 // Apple binaries. 485 FileSpecList filter_modules; 486 filter_modules.Append(FileSpec("libc++abi.dylib", false)); 487 filter_modules.Append(FileSpec("libSystem.B.dylib", false)); 488 return target.GetSearchFilterForModuleList(&filter_modules); 489 } else { 490 return LanguageRuntime::CreateExceptionSearchFilter(); 491 } 492 } 493 494 lldb::BreakpointSP ItaniumABILanguageRuntime::CreateExceptionBreakpoint( 495 bool catch_bp, bool throw_bp, bool for_expressions, bool is_internal) { 496 Target &target = m_process->GetTarget(); 497 FileSpecList filter_modules; 498 BreakpointResolverSP exception_resolver_sp = 499 CreateExceptionResolver(NULL, catch_bp, throw_bp, for_expressions); 500 SearchFilterSP filter_sp(CreateExceptionSearchFilter()); 501 const bool hardware = false; 502 const bool resolve_indirect_functions = false; 503 return target.CreateBreakpoint(filter_sp, exception_resolver_sp, is_internal, 504 hardware, resolve_indirect_functions); 505 } 506 507 void ItaniumABILanguageRuntime::SetExceptionBreakpoints() { 508 if (!m_process) 509 return; 510 511 const bool catch_bp = false; 512 const bool throw_bp = true; 513 const bool is_internal = true; 514 const bool for_expressions = true; 515 516 // For the exception breakpoints set by the Expression parser, we'll be a 517 // little more aggressive and stop at exception allocation as well. 518 519 if (m_cxx_exception_bp_sp) { 520 m_cxx_exception_bp_sp->SetEnabled(true); 521 } else { 522 m_cxx_exception_bp_sp = CreateExceptionBreakpoint( 523 catch_bp, throw_bp, for_expressions, is_internal); 524 if (m_cxx_exception_bp_sp) 525 m_cxx_exception_bp_sp->SetBreakpointKind("c++ exception"); 526 } 527 } 528 529 void ItaniumABILanguageRuntime::ClearExceptionBreakpoints() { 530 if (!m_process) 531 return; 532 533 if (m_cxx_exception_bp_sp) { 534 m_cxx_exception_bp_sp->SetEnabled(false); 535 } 536 } 537 538 bool ItaniumABILanguageRuntime::ExceptionBreakpointsAreSet() { 539 return m_cxx_exception_bp_sp && m_cxx_exception_bp_sp->IsEnabled(); 540 } 541 542 bool ItaniumABILanguageRuntime::ExceptionBreakpointsExplainStop( 543 lldb::StopInfoSP stop_reason) { 544 if (!m_process) 545 return false; 546 547 if (!stop_reason || stop_reason->GetStopReason() != eStopReasonBreakpoint) 548 return false; 549 550 uint64_t break_site_id = stop_reason->GetValue(); 551 return m_process->GetBreakpointSiteList().BreakpointSiteContainsBreakpoint( 552 break_site_id, m_cxx_exception_bp_sp->GetID()); 553 } 554 555 TypeAndOrName ItaniumABILanguageRuntime::GetDynamicTypeInfo( 556 const lldb_private::Address &vtable_addr) { 557 std::lock_guard<std::mutex> locker(m_dynamic_type_map_mutex); 558 DynamicTypeCache::const_iterator pos = m_dynamic_type_map.find(vtable_addr); 559 if (pos == m_dynamic_type_map.end()) 560 return TypeAndOrName(); 561 else 562 return pos->second; 563 } 564 565 void ItaniumABILanguageRuntime::SetDynamicTypeInfo( 566 const lldb_private::Address &vtable_addr, const TypeAndOrName &type_info) { 567 std::lock_guard<std::mutex> locker(m_dynamic_type_map_mutex); 568 m_dynamic_type_map[vtable_addr] = type_info; 569 } 570