contrib/llvm-project/lldb/source/Plugins/LanguageRuntime/CPlusPlus/ItaniumABI/ItaniumABILanguageRuntime.cpp

   1 //===-- ItaniumABILanguageRuntime.cpp --------------------------------------*-
   2 //C++ -*-===//
   3 //
   4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 // See https://llvm.org/LICENSE.txt for license information.
   6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #include "ItaniumABILanguageRuntime.h"
  11
  12 #include "lldb/Breakpoint/BreakpointLocation.h"
  13 #include "lldb/Core/Mangled.h"
  14 #include "lldb/Core/Module.h"
  15 #include "lldb/Core/PluginManager.h"
  16 #include "lldb/Core/ValueObject.h"
  17 #include "lldb/Core/ValueObjectMemory.h"
  18 #include "lldb/DataFormatters/FormattersHelpers.h"
  19 #include "lldb/Expression/DiagnosticManager.h"
  20 #include "lldb/Expression/FunctionCaller.h"
  21 #include "lldb/Interpreter/CommandObject.h"
  22 #include "lldb/Interpreter/CommandObjectMultiword.h"
  23 #include "lldb/Interpreter/CommandReturnObject.h"
  24 #include "lldb/Symbol/ClangASTContext.h"
  25 #include "lldb/Symbol/Symbol.h"
  26 #include "lldb/Symbol/SymbolFile.h"
  27 #include "lldb/Symbol/TypeList.h"
  28 #include "lldb/Target/Process.h"
  29 #include "lldb/Target/RegisterContext.h"
  30 #include "lldb/Target/SectionLoadList.h"
  31 #include "lldb/Target/StopInfo.h"
  32 #include "lldb/Target/Target.h"
  33 #include "lldb/Target/Thread.h"
  34 #include "lldb/Utility/ConstString.h"
  35 #include "lldb/Utility/Log.h"
  36 #include "lldb/Utility/Scalar.h"
  37 #include "lldb/Utility/Status.h"
  38
  39 #include <vector>
  40
  41 using namespace lldb;
  42 using namespace lldb_private;
  43
  44 static const char *vtable_demangled_prefix = "vtable for ";
  45
  46 char ItaniumABILanguageRuntime::ID = 0;
  47
  48 bool ItaniumABILanguageRuntime::CouldHaveDynamicValue(ValueObject &in_value) {
  49   const bool check_cxx = true;
  50   const bool check_objc = false;
  51   return in_value.GetCompilerType().IsPossibleDynamicType(nullptr, check_cxx,
  52                                                           check_objc);
  53 }
  54
  55 TypeAndOrName ItaniumABILanguageRuntime::GetTypeInfoFromVTableAddress(
  56     ValueObject &in_value, lldb::addr_t original_ptr,
  57     lldb::addr_t vtable_load_addr) {
  58   if (m_process && vtable_load_addr != LLDB_INVALID_ADDRESS) {
  59     // Find the symbol that contains the "vtable_load_addr" address
  60     Address vtable_addr;
  61     Target &target = m_process->GetTarget();
  62     if (!target.GetSectionLoadList().IsEmpty()) {
  63       if (target.GetSectionLoadList().ResolveLoadAddress(vtable_load_addr,
  64                                                          vtable_addr)) {
  65         // See if we have cached info for this type already
  66         TypeAndOrName type_info = GetDynamicTypeInfo(vtable_addr);
  67         if (type_info)
  68           return type_info;
  69
  70         SymbolContext sc;
  71         target.GetImages().ResolveSymbolContextForAddress(
  72             vtable_addr, eSymbolContextSymbol, sc);
  73         Symbol *symbol = sc.symbol;
  74         if (symbol != nullptr) {
  75           const char *name =
  76               symbol->GetMangled()
  77                   .GetDemangledName(lldb::eLanguageTypeC_plus_plus)
  78                   .AsCString();
  79           if (name && strstr(name, vtable_demangled_prefix) == name) {
  80             Log *log(
  81                 lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_OBJECT));
  82             if (log)
  83               log->Printf("0x%16.16" PRIx64
  84                           ": static-type = '%s' has vtable symbol '%s'\n",
  85                           original_ptr, in_value.GetTypeName().GetCString(),
  86                           name);
  87             // We are a C++ class, that's good.  Get the class name and look it
  88             // up:
  89             const char *class_name = name + strlen(vtable_demangled_prefix);
  90             // We know the class name is absolute, so tell FindTypes that by
  91             // prefixing it with the root namespace:
  92             std::string lookup_name("::");
  93             lookup_name.append(class_name);
  94
  95             type_info.SetName(class_name);
  96             const bool exact_match = true;
  97             TypeList class_types;
  98
  99             uint32_t num_matches = 0;
 100             // First look in the module that the vtable symbol came from and
 101             // look for a single exact match.
 102             llvm::DenseSet<SymbolFile *> searched_symbol_files;
 103             if (sc.module_sp) {
 104               num_matches = sc.module_sp->FindTypes(
 105                   ConstString(lookup_name), exact_match, 1,
 106                   searched_symbol_files, class_types);
 107             }
 108
 109             // If we didn't find a symbol, then move on to the entire module
 110             // list in the target and get as many unique matches as possible
 111             if (num_matches == 0) {
 112               num_matches = target.GetImages().FindTypes(
 113                   nullptr, ConstString(lookup_name), exact_match, UINT32_MAX,
 114                   searched_symbol_files, class_types);
 115             }
 116
 117             lldb::TypeSP type_sp;
 118             if (num_matches == 0) {
 119               if (log)
 120                 log->Printf("0x%16.16" PRIx64 ": is not dynamic\n",
 121                             original_ptr);
 122               return TypeAndOrName();
 123             }
 124             if (num_matches == 1) {
 125               type_sp = class_types.GetTypeAtIndex(0);
 126               if (type_sp) {
 127                 if (ClangASTContext::IsCXXClassType(
 128                         type_sp->GetForwardCompilerType())) {
 129                   if (log)
 130                     log->Printf(
 131                         "0x%16.16" PRIx64
 132                         ": static-type = '%s' has dynamic type: uid={0x%" PRIx64
 133                         "}, type-name='%s'\n",
 134                         original_ptr, in_value.GetTypeName().AsCString(),
 135                         type_sp->GetID(), type_sp->GetName().GetCString());
 136                   type_info.SetTypeSP(type_sp);
 137                 }
 138               }
 139             } else if (num_matches > 1) {
 140               size_t i;
 141               if (log) {
 142                 for (i = 0; i < num_matches; i++) {
 143                   type_sp = class_types.GetTypeAtIndex(i);
 144                   if (type_sp) {
 145                     if (log)
 146                       log->Printf(
 147                           "0x%16.16" PRIx64
 148                           ": static-type = '%s' has multiple matching dynamic "
 149                           "types: uid={0x%" PRIx64 "}, type-name='%s'\n",
 150                           original_ptr, in_value.GetTypeName().AsCString(),
 151                           type_sp->GetID(), type_sp->GetName().GetCString());
 152                   }
 153                 }
 154               }
 155
 156               for (i = 0; i < num_matches; i++) {
 157                 type_sp = class_types.GetTypeAtIndex(i);
 158                 if (type_sp) {
 159                   if (ClangASTContext::IsCXXClassType(
 160                           type_sp->GetForwardCompilerType())) {
 161                     if (log)
 162                       log->Printf(
 163                           "0x%16.16" PRIx64 ": static-type = '%s' has multiple "
 164                                             "matching dynamic types, picking "
 165                                             "this one: uid={0x%" PRIx64
 166                           "}, type-name='%s'\n",
 167                           original_ptr, in_value.GetTypeName().AsCString(),
 168                           type_sp->GetID(), type_sp->GetName().GetCString());
 169                     type_info.SetTypeSP(type_sp);
 170                   }
 171                 }
 172               }
 173
 174               if (log && i == num_matches) {
 175                 log->Printf(
 176                     "0x%16.16" PRIx64
 177                     ": static-type = '%s' has multiple matching dynamic "
 178                     "types, didn't find a C++ match\n",
 179                     original_ptr, in_value.GetTypeName().AsCString());
 180               }
 181             }
 182             if (type_info)
 183               SetDynamicTypeInfo(vtable_addr, type_info);
 184             return type_info;
 185           }
 186         }
 187       }
 188     }
 189   }
 190   return TypeAndOrName();
 191 }
 192
 193 bool ItaniumABILanguageRuntime::GetDynamicTypeAndAddress(
 194     ValueObject &in_value, lldb::DynamicValueType use_dynamic,
 195     TypeAndOrName &class_type_or_name, Address &dynamic_address,
 196     Value::ValueType &value_type) {
 197   // For Itanium, if the type has a vtable pointer in the object, it will be at
 198   // offset 0 in the object.  That will point to the "address point" within the
 199   // vtable (not the beginning of the vtable.)  We can then look up the symbol
 200   // containing this "address point" and that symbol's name demangled will
 201   // contain the full class name. The second pointer above the "address point"
 202   // is the "offset_to_top".  We'll use that to get the start of the value
 203   // object which holds the dynamic type.
 204   //
 205
 206   class_type_or_name.Clear();
 207   value_type = Value::ValueType::eValueTypeScalar;
 208
 209   // Only a pointer or reference type can have a different dynamic and static
 210   // type:
 211   if (!CouldHaveDynamicValue(in_value))
 212     return false;
 213
 214   // First job, pull out the address at 0 offset from the object.
 215   AddressType address_type;
 216   lldb::addr_t original_ptr = in_value.GetPointerValue(&address_type);
 217   if (original_ptr == LLDB_INVALID_ADDRESS)
 218     return false;
 219
 220   ExecutionContext exe_ctx(in_value.GetExecutionContextRef());
 221
 222   Process *process = exe_ctx.GetProcessPtr();
 223
 224   if (process == nullptr)
 225     return false;
 226
 227   Status error;
 228   const lldb::addr_t vtable_address_point =
 229       process->ReadPointerFromMemory(original_ptr, error);
 230
 231   if (!error.Success() || vtable_address_point == LLDB_INVALID_ADDRESS)
 232     return false;
 233
 234   class_type_or_name = GetTypeInfoFromVTableAddress(in_value, original_ptr,
 235                                                     vtable_address_point);
 236
 237   if (!class_type_or_name)
 238     return false;
 239
 240   CompilerType type = class_type_or_name.GetCompilerType();
 241   // There can only be one type with a given name, so we've just found
 242   // duplicate definitions, and this one will do as well as any other. We
 243   // don't consider something to have a dynamic type if it is the same as
 244   // the static type.  So compare against the value we were handed.
 245   if (!type)
 246     return true;
 247
 248   if (ClangASTContext::AreTypesSame(in_value.GetCompilerType(), type)) {
 249     // The dynamic type we found was the same type, so we don't have a
 250     // dynamic type here...
 251     return false;
 252   }
 253
 254   // The offset_to_top is two pointers above the vtable pointer.
 255   const uint32_t addr_byte_size = process->GetAddressByteSize();
 256   const lldb::addr_t offset_to_top_location =
 257       vtable_address_point - 2 * addr_byte_size;
 258   // Watch for underflow, offset_to_top_location should be less than
 259   // vtable_address_point
 260   if (offset_to_top_location >= vtable_address_point)
 261     return false;
 262   const int64_t offset_to_top = process->ReadSignedIntegerFromMemory(
 263       offset_to_top_location, addr_byte_size, INT64_MIN, error);
 264
 265   if (offset_to_top == INT64_MIN)
 266     return false;
 267   // So the dynamic type is a value that starts at offset_to_top above
 268   // the original address.
 269   lldb::addr_t dynamic_addr = original_ptr + offset_to_top;
 270   if (!process->GetTarget().GetSectionLoadList().ResolveLoadAddress(
 271           dynamic_addr, dynamic_address)) {
 272     dynamic_address.SetRawAddress(dynamic_addr);
 273   }
 274   return true;
 275 }
 276
 277 TypeAndOrName ItaniumABILanguageRuntime::FixUpDynamicType(
 278     const TypeAndOrName &type_and_or_name, ValueObject &static_value) {
 279   CompilerType static_type(static_value.GetCompilerType());
 280   Flags static_type_flags(static_type.GetTypeInfo());
 281
 282   TypeAndOrName ret(type_and_or_name);
 283   if (type_and_or_name.HasType()) {
 284     // The type will always be the type of the dynamic object.  If our parent's
 285     // type was a pointer, then our type should be a pointer to the type of the
 286     // dynamic object.  If a reference, then the original type should be
 287     // okay...
 288     CompilerType orig_type = type_and_or_name.GetCompilerType();
 289     CompilerType corrected_type = orig_type;
 290     if (static_type_flags.AllSet(eTypeIsPointer))
 291       corrected_type = orig_type.GetPointerType();
 292     else if (static_type_flags.AllSet(eTypeIsReference))
 293       corrected_type = orig_type.GetLValueReferenceType();
 294     ret.SetCompilerType(corrected_type);
 295   } else {
 296     // If we are here we need to adjust our dynamic type name to include the
 297     // correct & or * symbol
 298     std::string corrected_name(type_and_or_name.GetName().GetCString());
 299     if (static_type_flags.AllSet(eTypeIsPointer))
 300       corrected_name.append(" *");
 301     else if (static_type_flags.AllSet(eTypeIsReference))
 302       corrected_name.append(" &");
 303     // the parent type should be a correctly pointer'ed or referenc'ed type
 304     ret.SetCompilerType(static_type);
 305     ret.SetName(corrected_name.c_str());
 306   }
 307   return ret;
 308 }
 309
 310 // Static Functions
 311 LanguageRuntime *
 312 ItaniumABILanguageRuntime::CreateInstance(Process *process,
 313                                           lldb::LanguageType language) {
 314   // FIXME: We have to check the process and make sure we actually know that
 315   // this process supports
 316   // the Itanium ABI.
 317   if (language == eLanguageTypeC_plus_plus ||
 318       language == eLanguageTypeC_plus_plus_03 ||
 319       language == eLanguageTypeC_plus_plus_11 ||
 320       language == eLanguageTypeC_plus_plus_14)
 321     return new ItaniumABILanguageRuntime(process);
 322   else
 323     return nullptr;
 324 }
 325
 326 class CommandObjectMultiwordItaniumABI_Demangle : public CommandObjectParsed {
 327 public:
 328   CommandObjectMultiwordItaniumABI_Demangle(CommandInterpreter &interpreter)
 329       : CommandObjectParsed(interpreter, "demangle",
 330                             "Demangle a C++ mangled name.",
 331                             "language cplusplus demangle") {
 332     CommandArgumentEntry arg;
 333     CommandArgumentData index_arg;
 334
 335     // Define the first (and only) variant of this arg.
 336     index_arg.arg_type = eArgTypeSymbol;
 337     index_arg.arg_repetition = eArgRepeatPlus;
 338
 339     // There is only one variant this argument could be; put it into the
 340     // argument entry.
 341     arg.push_back(index_arg);
 342
 343     // Push the data for the first argument into the m_arguments vector.
 344     m_arguments.push_back(arg);
 345   }
 346
 347   ~CommandObjectMultiwordItaniumABI_Demangle() override = default;
 348
 349 protected:
 350   bool DoExecute(Args &command, CommandReturnObject &result) override {
 351     bool demangled_any = false;
 352     bool error_any = false;
 353     for (auto &entry : command.entries()) {
 354       if (entry.ref.empty())
 355         continue;
 356
 357       // the actual Mangled class should be strict about this, but on the
 358       // command line if you're copying mangled names out of 'nm' on Darwin,
 359       // they will come out with an extra underscore - be willing to strip this
 360       // on behalf of the user.   This is the moral equivalent of the -_/-n
 361       // options to c++filt
 362       auto name = entry.ref;
 363       if (name.startswith("__Z"))
 364         name = name.drop_front();
 365
 366       Mangled mangled(name, true);
 367       if (mangled.GuessLanguage() == lldb::eLanguageTypeC_plus_plus) {
 368         ConstString demangled(
 369             mangled.GetDisplayDemangledName(lldb::eLanguageTypeC_plus_plus));
 370         demangled_any = true;
 371         result.AppendMessageWithFormat("%s ---> %s\n", entry.ref.str().c_str(),
 372                                        demangled.GetCString());
 373       } else {
 374         error_any = true;
 375         result.AppendErrorWithFormat("%s is not a valid C++ mangled name\n",
 376                                      entry.ref.str().c_str());
 377       }
 378     }
 379
 380     result.SetStatus(
 381         error_any ? lldb::eReturnStatusFailed
 382                   : (demangled_any ? lldb::eReturnStatusSuccessFinishResult
 383                                    : lldb::eReturnStatusSuccessFinishNoResult));
 384     return result.Succeeded();
 385   }
 386 };
 387
 388 class CommandObjectMultiwordItaniumABI : public CommandObjectMultiword {
 389 public:
 390   CommandObjectMultiwordItaniumABI(CommandInterpreter &interpreter)
 391       : CommandObjectMultiword(
 392             interpreter, "cplusplus",
 393             "Commands for operating on the C++ language runtime.",
 394             "cplusplus <subcommand> [<subcommand-options>]") {
 395     LoadSubCommand(
 396         "demangle",
 397         CommandObjectSP(
 398             new CommandObjectMultiwordItaniumABI_Demangle(interpreter)));
 399   }
 400
 401   ~CommandObjectMultiwordItaniumABI() override = default;
 402 };
 403
 404 void ItaniumABILanguageRuntime::Initialize() {
 405   PluginManager::RegisterPlugin(
 406       GetPluginNameStatic(), "Itanium ABI for the C++ language", CreateInstance,
 407       [](CommandInterpreter &interpreter) -> lldb::CommandObjectSP {
 408         return CommandObjectSP(
 409             new CommandObjectMultiwordItaniumABI(interpreter));
 410       });
 411 }
 412
 413 void ItaniumABILanguageRuntime::Terminate() {
 414   PluginManager::UnregisterPlugin(CreateInstance);
 415 }
 416
 417 lldb_private::ConstString ItaniumABILanguageRuntime::GetPluginNameStatic() {
 418   static ConstString g_name("itanium");
 419   return g_name;
 420 }
 421
 422 // PluginInterface protocol
 423 lldb_private::ConstString ItaniumABILanguageRuntime::GetPluginName() {
 424   return GetPluginNameStatic();
 425 }
 426
 427 uint32_t ItaniumABILanguageRuntime::GetPluginVersion() { return 1; }
 428
 429 BreakpointResolverSP ItaniumABILanguageRuntime::CreateExceptionResolver(
 430     Breakpoint *bkpt, bool catch_bp, bool throw_bp) {
 431   return CreateExceptionResolver(bkpt, catch_bp, throw_bp, false);
 432 }
 433
 434 BreakpointResolverSP ItaniumABILanguageRuntime::CreateExceptionResolver(
 435     Breakpoint *bkpt, bool catch_bp, bool throw_bp, bool for_expressions) {
 436   // One complication here is that most users DON'T want to stop at
 437   // __cxa_allocate_expression, but until we can do anything better with
 438   // predicting unwinding the expression parser does.  So we have two forms of
 439   // the exception breakpoints, one for expressions that leaves out
 440   // __cxa_allocate_exception, and one that includes it. The
 441   // SetExceptionBreakpoints does the latter, the CreateExceptionBreakpoint in
 442   // the runtime the former.
 443   static const char *g_catch_name = "__cxa_begin_catch";
 444   static const char *g_throw_name1 = "__cxa_throw";
 445   static const char *g_throw_name2 = "__cxa_rethrow";
 446   static const char *g_exception_throw_name = "__cxa_allocate_exception";
 447   std::vector<const char *> exception_names;
 448   exception_names.reserve(4);
 449   if (catch_bp)
 450     exception_names.push_back(g_catch_name);
 451
 452   if (throw_bp) {
 453     exception_names.push_back(g_throw_name1);
 454     exception_names.push_back(g_throw_name2);
 455   }
 456
 457   if (for_expressions)
 458     exception_names.push_back(g_exception_throw_name);
 459
 460   BreakpointResolverSP resolver_sp(new BreakpointResolverName(
 461       bkpt, exception_names.data(), exception_names.size(),
 462       eFunctionNameTypeBase, eLanguageTypeUnknown, 0, eLazyBoolNo));
 463
 464   return resolver_sp;
 465 }
 466
 467 lldb::SearchFilterSP ItaniumABILanguageRuntime::CreateExceptionSearchFilter() {
 468   Target &target = m_process->GetTarget();
 469
 470   FileSpecList filter_modules;
 471   if (target.GetArchitecture().GetTriple().getVendor() == llvm::Triple::Apple) {
 472     // Limit the number of modules that are searched for these breakpoints for
 473     // Apple binaries.
 474     filter_modules.Append(FileSpec("libc++abi.dylib"));
 475     filter_modules.Append(FileSpec("libSystem.B.dylib"));
 476   }
 477   return target.GetSearchFilterForModuleList(&filter_modules);
 478 }
 479
 480 lldb::BreakpointSP ItaniumABILanguageRuntime::CreateExceptionBreakpoint(
 481     bool catch_bp, bool throw_bp, bool for_expressions, bool is_internal) {
 482   Target &target = m_process->GetTarget();
 483   FileSpecList filter_modules;
 484   BreakpointResolverSP exception_resolver_sp =
 485       CreateExceptionResolver(nullptr, catch_bp, throw_bp, for_expressions);
 486   SearchFilterSP filter_sp(CreateExceptionSearchFilter());
 487   const bool hardware = false;
 488   const bool resolve_indirect_functions = false;
 489   return target.CreateBreakpoint(filter_sp, exception_resolver_sp, is_internal,
 490                                  hardware, resolve_indirect_functions);
 491 }
 492
 493 void ItaniumABILanguageRuntime::SetExceptionBreakpoints() {
 494   if (!m_process)
 495     return;
 496
 497   const bool catch_bp = false;
 498   const bool throw_bp = true;
 499   const bool is_internal = true;
 500   const bool for_expressions = true;
 501
 502   // For the exception breakpoints set by the Expression parser, we'll be a
 503   // little more aggressive and stop at exception allocation as well.
 504
 505   if (m_cxx_exception_bp_sp) {
 506     m_cxx_exception_bp_sp->SetEnabled(true);
 507   } else {
 508     m_cxx_exception_bp_sp = CreateExceptionBreakpoint(
 509         catch_bp, throw_bp, for_expressions, is_internal);
 510     if (m_cxx_exception_bp_sp)
 511       m_cxx_exception_bp_sp->SetBreakpointKind("c++ exception");
 512   }
 513 }
 514
 515 void ItaniumABILanguageRuntime::ClearExceptionBreakpoints() {
 516   if (!m_process)
 517     return;
 518
 519   if (m_cxx_exception_bp_sp) {
 520     m_cxx_exception_bp_sp->SetEnabled(false);
 521   }
 522 }
 523
 524 bool ItaniumABILanguageRuntime::ExceptionBreakpointsAreSet() {
 525   return m_cxx_exception_bp_sp && m_cxx_exception_bp_sp->IsEnabled();
 526 }
 527
 528 bool ItaniumABILanguageRuntime::ExceptionBreakpointsExplainStop(
 529     lldb::StopInfoSP stop_reason) {
 530   if (!m_process)
 531     return false;
 532
 533   if (!stop_reason || stop_reason->GetStopReason() != eStopReasonBreakpoint)
 534     return false;
 535
 536   uint64_t break_site_id = stop_reason->GetValue();
 537   return m_process->GetBreakpointSiteList().BreakpointSiteContainsBreakpoint(
 538       break_site_id, m_cxx_exception_bp_sp->GetID());
 539 }
 540
 541 ValueObjectSP ItaniumABILanguageRuntime::GetExceptionObjectForThread(
 542     ThreadSP thread_sp) {
 543   if (!thread_sp->SafeToCallFunctions())
 544     return {};
 545
 546   ClangASTContext *clang_ast_context =
 547       m_process->GetTarget().GetScratchClangASTContext();
 548   CompilerType voidstar =
 549       clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
 550
 551   DiagnosticManager diagnostics;
 552   ExecutionContext exe_ctx;
 553   EvaluateExpressionOptions options;
 554
 555   options.SetUnwindOnError(true);
 556   options.SetIgnoreBreakpoints(true);
 557   options.SetStopOthers(true);
 558   options.SetTimeout(m_process->GetUtilityExpressionTimeout());
 559   options.SetTryAllThreads(false);
 560   thread_sp->CalculateExecutionContext(exe_ctx);
 561
 562   const ModuleList &modules = m_process->GetTarget().GetImages();
 563   SymbolContextList contexts;
 564   SymbolContext context;
 565
 566   modules.FindSymbolsWithNameAndType(
 567       ConstString("__cxa_current_exception_type"), eSymbolTypeCode, contexts);
 568   contexts.GetContextAtIndex(0, context);
 569   Address addr = context.symbol->GetAddress();
 570
 571   Status error;
 572   FunctionCaller *function_caller =
 573       m_process->GetTarget().GetFunctionCallerForLanguage(
 574           eLanguageTypeC, voidstar, addr, ValueList(), "caller", error);
 575
 576   ExpressionResults func_call_ret;
 577   Value results;
 578   func_call_ret = function_caller->ExecuteFunction(exe_ctx, nullptr, options,
 579                                                    diagnostics, results);
 580   if (func_call_ret != eExpressionCompleted || !error.Success()) {
 581     return ValueObjectSP();
 582   }
 583
 584   size_t ptr_size = m_process->GetAddressByteSize();
 585   addr_t result_ptr = results.GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
 586   addr_t exception_addr =
 587       m_process->ReadPointerFromMemory(result_ptr - ptr_size, error);
 588
 589   if (!error.Success()) {
 590     return ValueObjectSP();
 591   }
 592
 593   lldb_private::formatters::InferiorSizedWord exception_isw(exception_addr,
 594                                                             *m_process);
 595   ValueObjectSP exception = ValueObject::CreateValueObjectFromData(
 596       "exception", exception_isw.GetAsData(m_process->GetByteOrder()), exe_ctx,
 597       voidstar);
 598   exception = exception->GetDynamicValue(eDynamicDontRunTarget);
 599
 600   return exception;
 601 }
 602
 603 TypeAndOrName ItaniumABILanguageRuntime::GetDynamicTypeInfo(
 604     const lldb_private::Address &vtable_addr) {
 605   std::lock_guard<std::mutex> locker(m_dynamic_type_map_mutex);
 606   DynamicTypeCache::const_iterator pos = m_dynamic_type_map.find(vtable_addr);
 607   if (pos == m_dynamic_type_map.end())
 608     return TypeAndOrName();
 609   else
 610     return pos->second;
 611 }
 612
 613 void ItaniumABILanguageRuntime::SetDynamicTypeInfo(
 614     const lldb_private::Address &vtable_addr, const TypeAndOrName &type_info) {
 615   std::lock_guard<std::mutex> locker(m_dynamic_type_map_mutex);
 616   m_dynamic_type_map[vtable_addr] = type_info;
 617 }