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/ValueObject.h" 18 #include "lldb/Core/ValueObjectMemory.h" 19 #include "lldb/Interpreter/CommandObject.h" 20 #include "lldb/Interpreter/CommandObjectMultiword.h" 21 #include "lldb/Interpreter/CommandReturnObject.h" 22 #include "lldb/Symbol/ClangASTContext.h" 23 #include "lldb/Symbol/Symbol.h" 24 #include "lldb/Symbol/SymbolFile.h" 25 #include "lldb/Symbol/TypeList.h" 26 #include "lldb/Target/Process.h" 27 #include "lldb/Target/RegisterContext.h" 28 #include "lldb/Target/SectionLoadList.h" 29 #include "lldb/Target/StopInfo.h" 30 #include "lldb/Target/Target.h" 31 #include "lldb/Target/Thread.h" 32 #include "lldb/Utility/ConstString.h" 33 #include "lldb/Utility/Log.h" 34 #include "lldb/Utility/Scalar.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 return false; 209 210 // First job, pull out the address at 0 offset from the object. 211 AddressType address_type; 212 lldb::addr_t original_ptr = in_value.GetPointerValue(&address_type); 213 if (original_ptr == LLDB_INVALID_ADDRESS) 214 return false; 215 216 ExecutionContext exe_ctx(in_value.GetExecutionContextRef()); 217 218 Process *process = exe_ctx.GetProcessPtr(); 219 220 if (process == nullptr) 221 return false; 222 223 Status error; 224 const lldb::addr_t vtable_address_point = 225 process->ReadPointerFromMemory(original_ptr, error); 226 227 if (!error.Success() || vtable_address_point == LLDB_INVALID_ADDRESS) 228 return false; 229 230 class_type_or_name = GetTypeInfoFromVTableAddress(in_value, original_ptr, 231 vtable_address_point); 232 233 if (!class_type_or_name) 234 return false; 235 236 TypeSP type_sp = class_type_or_name.GetTypeSP(); 237 // There can only be one type with a given name, so we've just found 238 // duplicate definitions, and this one will do as well as any other. We 239 // don't consider something to have a dynamic type if it is the same as 240 // the static type. So compare against the value we were handed. 241 if (!type_sp) 242 return true; 243 244 if (ClangASTContext::AreTypesSame(in_value.GetCompilerType(), 245 type_sp->GetForwardCompilerType())) { 246 // The dynamic type we found was the same type, so we don't have a 247 // dynamic type here... 248 return false; 249 } 250 251 // The offset_to_top is two pointers above the vtable pointer. 252 const uint32_t addr_byte_size = process->GetAddressByteSize(); 253 const lldb::addr_t offset_to_top_location = 254 vtable_address_point - 2 * addr_byte_size; 255 // Watch for underflow, offset_to_top_location should be less than 256 // vtable_address_point 257 if (offset_to_top_location >= vtable_address_point) 258 return false; 259 const int64_t offset_to_top = process->ReadSignedIntegerFromMemory( 260 offset_to_top_location, addr_byte_size, INT64_MIN, error); 261 262 if (offset_to_top == INT64_MIN) 263 return false; 264 // So the dynamic type is a value that starts at offset_to_top above 265 // the original address. 266 lldb::addr_t dynamic_addr = original_ptr + offset_to_top; 267 if (!process->GetTarget().GetSectionLoadList().ResolveLoadAddress( 268 dynamic_addr, dynamic_address)) { 269 dynamic_address.SetRawAddress(dynamic_addr); 270 } 271 return true; 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 return strstr(name, "_vptr$") == name; 313 } 314 315 //------------------------------------------------------------------ 316 // Static Functions 317 //------------------------------------------------------------------ 318 LanguageRuntime * 319 ItaniumABILanguageRuntime::CreateInstance(Process *process, 320 lldb::LanguageType language) { 321 // FIXME: We have to check the process and make sure we actually know that 322 // this process supports 323 // the Itanium ABI. 324 if (language == eLanguageTypeC_plus_plus || 325 language == eLanguageTypeC_plus_plus_03 || 326 language == eLanguageTypeC_plus_plus_11 || 327 language == eLanguageTypeC_plus_plus_14) 328 return new ItaniumABILanguageRuntime(process); 329 else 330 return NULL; 331 } 332 333 class CommandObjectMultiwordItaniumABI_Demangle : public CommandObjectParsed { 334 public: 335 CommandObjectMultiwordItaniumABI_Demangle(CommandInterpreter &interpreter) 336 : CommandObjectParsed(interpreter, "demangle", 337 "Demangle a C++ mangled name.", 338 "language cplusplus demangle") { 339 CommandArgumentEntry arg; 340 CommandArgumentData index_arg; 341 342 // Define the first (and only) variant of this arg. 343 index_arg.arg_type = eArgTypeSymbol; 344 index_arg.arg_repetition = eArgRepeatPlus; 345 346 // There is only one variant this argument could be; put it into the 347 // argument entry. 348 arg.push_back(index_arg); 349 350 // Push the data for the first argument into the m_arguments vector. 351 m_arguments.push_back(arg); 352 } 353 354 ~CommandObjectMultiwordItaniumABI_Demangle() override = default; 355 356 protected: 357 bool DoExecute(Args &command, CommandReturnObject &result) override { 358 bool demangled_any = false; 359 bool error_any = false; 360 for (auto &entry : command.entries()) { 361 if (entry.ref.empty()) 362 continue; 363 364 // the actual Mangled class should be strict about this, but on the 365 // command line if you're copying mangled names out of 'nm' on Darwin, 366 // they will come out with an extra underscore - be willing to strip this 367 // on behalf of the user. This is the moral equivalent of the -_/-n 368 // options to c++filt 369 auto name = entry.ref; 370 if (name.startswith("__Z")) 371 name = name.drop_front(); 372 373 Mangled mangled(name, true); 374 if (mangled.GuessLanguage() == lldb::eLanguageTypeC_plus_plus) { 375 ConstString demangled( 376 mangled.GetDisplayDemangledName(lldb::eLanguageTypeC_plus_plus)); 377 demangled_any = true; 378 result.AppendMessageWithFormat("%s ---> %s\n", entry.ref.str().c_str(), 379 demangled.GetCString()); 380 } else { 381 error_any = true; 382 result.AppendErrorWithFormat("%s is not a valid C++ mangled name\n", 383 entry.ref.str().c_str()); 384 } 385 } 386 387 result.SetStatus( 388 error_any ? lldb::eReturnStatusFailed 389 : (demangled_any ? lldb::eReturnStatusSuccessFinishResult 390 : lldb::eReturnStatusSuccessFinishNoResult)); 391 return result.Succeeded(); 392 } 393 }; 394 395 class CommandObjectMultiwordItaniumABI : public CommandObjectMultiword { 396 public: 397 CommandObjectMultiwordItaniumABI(CommandInterpreter &interpreter) 398 : CommandObjectMultiword( 399 interpreter, "cplusplus", 400 "Commands for operating on the C++ language runtime.", 401 "cplusplus <subcommand> [<subcommand-options>]") { 402 LoadSubCommand( 403 "demangle", 404 CommandObjectSP( 405 new CommandObjectMultiwordItaniumABI_Demangle(interpreter))); 406 } 407 408 ~CommandObjectMultiwordItaniumABI() override = default; 409 }; 410 411 void ItaniumABILanguageRuntime::Initialize() { 412 PluginManager::RegisterPlugin( 413 GetPluginNameStatic(), "Itanium ABI for the C++ language", CreateInstance, 414 [](CommandInterpreter &interpreter) -> lldb::CommandObjectSP { 415 return CommandObjectSP( 416 new CommandObjectMultiwordItaniumABI(interpreter)); 417 }); 418 } 419 420 void ItaniumABILanguageRuntime::Terminate() { 421 PluginManager::UnregisterPlugin(CreateInstance); 422 } 423 424 lldb_private::ConstString ItaniumABILanguageRuntime::GetPluginNameStatic() { 425 static ConstString g_name("itanium"); 426 return g_name; 427 } 428 429 //------------------------------------------------------------------ 430 // PluginInterface protocol 431 //------------------------------------------------------------------ 432 lldb_private::ConstString ItaniumABILanguageRuntime::GetPluginName() { 433 return GetPluginNameStatic(); 434 } 435 436 uint32_t ItaniumABILanguageRuntime::GetPluginVersion() { return 1; } 437 438 BreakpointResolverSP ItaniumABILanguageRuntime::CreateExceptionResolver( 439 Breakpoint *bkpt, bool catch_bp, bool throw_bp) { 440 return CreateExceptionResolver(bkpt, catch_bp, throw_bp, false); 441 } 442 443 BreakpointResolverSP ItaniumABILanguageRuntime::CreateExceptionResolver( 444 Breakpoint *bkpt, bool catch_bp, bool throw_bp, bool for_expressions) { 445 // One complication here is that most users DON'T want to stop at 446 // __cxa_allocate_expression, but until we can do anything better with 447 // predicting unwinding the expression parser does. So we have two forms of 448 // the exception breakpoints, one for expressions that leaves out 449 // __cxa_allocate_exception, and one that includes it. The 450 // SetExceptionBreakpoints does the latter, the CreateExceptionBreakpoint in 451 // the runtime the former. 452 static const char *g_catch_name = "__cxa_begin_catch"; 453 static const char *g_throw_name1 = "__cxa_throw"; 454 static const char *g_throw_name2 = "__cxa_rethrow"; 455 static const char *g_exception_throw_name = "__cxa_allocate_exception"; 456 std::vector<const char *> exception_names; 457 exception_names.reserve(4); 458 if (catch_bp) 459 exception_names.push_back(g_catch_name); 460 461 if (throw_bp) { 462 exception_names.push_back(g_throw_name1); 463 exception_names.push_back(g_throw_name2); 464 } 465 466 if (for_expressions) 467 exception_names.push_back(g_exception_throw_name); 468 469 BreakpointResolverSP resolver_sp(new BreakpointResolverName( 470 bkpt, exception_names.data(), exception_names.size(), 471 eFunctionNameTypeBase, eLanguageTypeUnknown, 0, eLazyBoolNo)); 472 473 return resolver_sp; 474 } 475 476 lldb::SearchFilterSP ItaniumABILanguageRuntime::CreateExceptionSearchFilter() { 477 Target &target = m_process->GetTarget(); 478 479 if (target.GetArchitecture().GetTriple().getVendor() == llvm::Triple::Apple) { 480 // Limit the number of modules that are searched for these breakpoints for 481 // Apple binaries. 482 FileSpecList filter_modules; 483 filter_modules.Append(FileSpec("libc++abi.dylib")); 484 filter_modules.Append(FileSpec("libSystem.B.dylib")); 485 return target.GetSearchFilterForModuleList(&filter_modules); 486 } else { 487 return LanguageRuntime::CreateExceptionSearchFilter(); 488 } 489 } 490 491 lldb::BreakpointSP ItaniumABILanguageRuntime::CreateExceptionBreakpoint( 492 bool catch_bp, bool throw_bp, bool for_expressions, bool is_internal) { 493 Target &target = m_process->GetTarget(); 494 FileSpecList filter_modules; 495 BreakpointResolverSP exception_resolver_sp = 496 CreateExceptionResolver(NULL, catch_bp, throw_bp, for_expressions); 497 SearchFilterSP filter_sp(CreateExceptionSearchFilter()); 498 const bool hardware = false; 499 const bool resolve_indirect_functions = false; 500 return target.CreateBreakpoint(filter_sp, exception_resolver_sp, is_internal, 501 hardware, resolve_indirect_functions); 502 } 503 504 void ItaniumABILanguageRuntime::SetExceptionBreakpoints() { 505 if (!m_process) 506 return; 507 508 const bool catch_bp = false; 509 const bool throw_bp = true; 510 const bool is_internal = true; 511 const bool for_expressions = true; 512 513 // For the exception breakpoints set by the Expression parser, we'll be a 514 // little more aggressive and stop at exception allocation as well. 515 516 if (m_cxx_exception_bp_sp) { 517 m_cxx_exception_bp_sp->SetEnabled(true); 518 } else { 519 m_cxx_exception_bp_sp = CreateExceptionBreakpoint( 520 catch_bp, throw_bp, for_expressions, is_internal); 521 if (m_cxx_exception_bp_sp) 522 m_cxx_exception_bp_sp->SetBreakpointKind("c++ exception"); 523 } 524 } 525 526 void ItaniumABILanguageRuntime::ClearExceptionBreakpoints() { 527 if (!m_process) 528 return; 529 530 if (m_cxx_exception_bp_sp) { 531 m_cxx_exception_bp_sp->SetEnabled(false); 532 } 533 } 534 535 bool ItaniumABILanguageRuntime::ExceptionBreakpointsAreSet() { 536 return m_cxx_exception_bp_sp && m_cxx_exception_bp_sp->IsEnabled(); 537 } 538 539 bool ItaniumABILanguageRuntime::ExceptionBreakpointsExplainStop( 540 lldb::StopInfoSP stop_reason) { 541 if (!m_process) 542 return false; 543 544 if (!stop_reason || stop_reason->GetStopReason() != eStopReasonBreakpoint) 545 return false; 546 547 uint64_t break_site_id = stop_reason->GetValue(); 548 return m_process->GetBreakpointSiteList().BreakpointSiteContainsBreakpoint( 549 break_site_id, m_cxx_exception_bp_sp->GetID()); 550 } 551 552 TypeAndOrName ItaniumABILanguageRuntime::GetDynamicTypeInfo( 553 const lldb_private::Address &vtable_addr) { 554 std::lock_guard<std::mutex> locker(m_dynamic_type_map_mutex); 555 DynamicTypeCache::const_iterator pos = m_dynamic_type_map.find(vtable_addr); 556 if (pos == m_dynamic_type_map.end()) 557 return TypeAndOrName(); 558 else 559 return pos->second; 560 } 561 562 void ItaniumABILanguageRuntime::SetDynamicTypeInfo( 563 const lldb_private::Address &vtable_addr, const TypeAndOrName &type_info) { 564 std::lock_guard<std::mutex> locker(m_dynamic_type_map_mutex); 565 m_dynamic_type_map[vtable_addr] = type_info; 566 } 567