1 //===-- ItaniumABILanguageRuntime.cpp --------------------------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #include "ItaniumABILanguageRuntime.h" 11 12 #include "lldb/Breakpoint/BreakpointLocation.h" 13 #include "lldb/Core/ConstString.h" 14 #include "lldb/Core/Error.h" 15 #include "lldb/Core/Log.h" 16 #include "lldb/Core/Module.h" 17 #include "lldb/Core/PluginManager.h" 18 #include "lldb/Core/Scalar.h" 19 #include "lldb/Core/ValueObject.h" 20 #include "lldb/Core/ValueObjectMemory.h" 21 #include "lldb/Symbol/ClangASTContext.h" 22 #include "lldb/Symbol/Symbol.h" 23 #include "lldb/Symbol/TypeList.h" 24 #include "lldb/Target/Process.h" 25 #include "lldb/Target/RegisterContext.h" 26 #include "lldb/Target/StopInfo.h" 27 #include "lldb/Target/Target.h" 28 #include "lldb/Target/Thread.h" 29 30 #include <vector> 31 32 using namespace lldb; 33 using namespace lldb_private; 34 35 static const char *pluginName = "ItaniumABILanguageRuntime"; 36 static const char *pluginDesc = "Itanium ABI for the C++ language"; 37 static const char *pluginShort = "language.itanium"; 38 static const char *vtable_demangled_prefix = "vtable for "; 39 40 bool 41 ItaniumABILanguageRuntime::CouldHaveDynamicValue (ValueObject &in_value) 42 { 43 return ClangASTContext::IsPossibleDynamicType(in_value.GetClangAST(), in_value.GetClangType(), NULL, 44 true, // check for C++ 45 false); // do not check for ObjC 46 } 47 48 bool 49 ItaniumABILanguageRuntime::GetDynamicTypeAndAddress (ValueObject &in_value, 50 lldb::DynamicValueType use_dynamic, 51 TypeAndOrName &class_type_or_name, 52 Address &dynamic_address) 53 { 54 // For Itanium, if the type has a vtable pointer in the object, it will be at offset 0 55 // in the object. That will point to the "address point" within the vtable (not the beginning of the 56 // vtable.) We can then look up the symbol containing this "address point" and that symbol's name 57 // demangled will contain the full class name. 58 // The second pointer above the "address point" is the "offset_to_top". We'll use that to get the 59 // start of the value object which holds the dynamic type. 60 // 61 62 class_type_or_name.Clear(); 63 64 // Only a pointer or reference type can have a different dynamic and static type: 65 if (CouldHaveDynamicValue (in_value)) 66 { 67 // First job, pull out the address at 0 offset from the object. 68 AddressType address_type; 69 lldb::addr_t original_ptr = in_value.GetPointerValue(&address_type); 70 if (original_ptr == LLDB_INVALID_ADDRESS) 71 return false; 72 73 ExecutionContext exe_ctx (in_value.GetExecutionContextRef()); 74 75 Target *target = exe_ctx.GetTargetPtr(); 76 Process *process = exe_ctx.GetProcessPtr(); 77 78 char memory_buffer[16]; 79 DataExtractor data(memory_buffer, sizeof(memory_buffer), 80 process->GetByteOrder(), 81 process->GetAddressByteSize()); 82 size_t address_byte_size = process->GetAddressByteSize(); 83 Error error; 84 size_t bytes_read = process->ReadMemory (original_ptr, 85 memory_buffer, 86 address_byte_size, 87 error); 88 if (!error.Success() || (bytes_read != address_byte_size)) 89 { 90 return false; 91 } 92 93 lldb::offset_t offset = 0; 94 lldb::addr_t vtable_address_point = data.GetAddress (&offset); 95 96 if (offset == 0) 97 return false; 98 99 // Now find the symbol that contains this address: 100 101 SymbolContext sc; 102 Address address_point_address; 103 if (target && !target->GetSectionLoadList().IsEmpty()) 104 { 105 if (target->GetSectionLoadList().ResolveLoadAddress (vtable_address_point, address_point_address)) 106 { 107 target->GetImages().ResolveSymbolContextForAddress (address_point_address, eSymbolContextSymbol, sc); 108 Symbol *symbol = sc.symbol; 109 if (symbol != NULL) 110 { 111 const char *name = symbol->GetMangled().GetDemangledName().AsCString(); 112 if (strstr(name, vtable_demangled_prefix) == name) 113 { 114 LogSP log (lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_OBJECT)); 115 if (log) 116 log->Printf ("0x%16.16" PRIx64 ": static-type = '%s' has vtable symbol '%s'\n", 117 original_ptr, 118 in_value.GetTypeName().GetCString(), 119 name); 120 // We are a C++ class, that's good. Get the class name and look it up: 121 const char *class_name = name + strlen(vtable_demangled_prefix); 122 class_type_or_name.SetName (class_name); 123 const bool exact_match = true; 124 TypeList class_types; 125 126 uint32_t num_matches = 0; 127 // First look in the module that the vtable symbol came from 128 // and look for a single exact match. 129 if (sc.module_sp) 130 { 131 num_matches = sc.module_sp->FindTypes (sc, 132 ConstString(class_name), 133 exact_match, 134 1, 135 class_types); 136 } 137 138 // If we didn't find a symbol, then move on to the entire 139 // module list in the target and get as many unique matches 140 // as possible 141 if (num_matches == 0) 142 { 143 num_matches = target->GetImages().FindTypes (sc, 144 ConstString(class_name), 145 exact_match, 146 UINT32_MAX, 147 class_types); 148 } 149 150 lldb::TypeSP type_sp; 151 if (num_matches == 0) 152 { 153 if (log) 154 log->Printf("0x%16.16" PRIx64 ": is not dynamic\n", original_ptr); 155 return false; 156 } 157 if (num_matches == 1) 158 { 159 type_sp = class_types.GetTypeAtIndex(0); 160 if (log) 161 log->Printf ("0x%16.16" PRIx64 ": static-type = '%s' has dynamic type: uid={0x%" PRIx64 "}, type-name='%s'\n", 162 original_ptr, 163 in_value.GetTypeName().AsCString(), 164 type_sp->GetID(), 165 type_sp->GetName().GetCString()); 166 167 class_type_or_name.SetTypeSP(class_types.GetTypeAtIndex(0)); 168 } 169 else if (num_matches > 1) 170 { 171 size_t i; 172 if (log) 173 { 174 for (i = 0; i < num_matches; i++) 175 { 176 type_sp = class_types.GetTypeAtIndex(i); 177 if (type_sp) 178 { 179 if (log) 180 log->Printf ("0x%16.16" PRIx64 ": static-type = '%s' has multiple matching dynamic types: uid={0x%" PRIx64 "}, type-name='%s'\n", 181 original_ptr, 182 in_value.GetTypeName().AsCString(), 183 type_sp->GetID(), 184 type_sp->GetName().GetCString()); 185 } 186 } 187 } 188 189 for (i = 0; i < num_matches; i++) 190 { 191 type_sp = class_types.GetTypeAtIndex(i); 192 if (type_sp) 193 { 194 if (ClangASTContext::IsCXXClassType(type_sp->GetClangFullType())) 195 { 196 if (log) 197 log->Printf ("0x%16.16" PRIx64 ": static-type = '%s' has multiple matching dynamic types, picking this one: uid={0x%" PRIx64 "}, type-name='%s'\n", 198 original_ptr, 199 in_value.GetTypeName().AsCString(), 200 type_sp->GetID(), 201 type_sp->GetName().GetCString()); 202 class_type_or_name.SetTypeSP(type_sp); 203 break; 204 } 205 } 206 } 207 208 if (i == num_matches) 209 { 210 if (log) 211 log->Printf ("0x%16.16" PRIx64 ": static-type = '%s' has multiple matching dynamic types, didn't find a C++ match\n", 212 original_ptr, 213 in_value.GetTypeName().AsCString()); 214 return false; 215 } 216 } 217 218 // There can only be one type with a given name, 219 // so we've just found duplicate definitions, and this 220 // one will do as well as any other. 221 // We don't consider something to have a dynamic type if 222 // it is the same as the static type. So compare against 223 // the value we were handed. 224 if (type_sp) 225 { 226 clang::ASTContext *in_ast_ctx = in_value.GetClangAST (); 227 clang::ASTContext *this_ast_ctx = type_sp->GetClangAST (); 228 if (in_ast_ctx == this_ast_ctx) 229 { 230 if (ClangASTContext::AreTypesSame (in_ast_ctx, 231 in_value.GetClangType(), 232 type_sp->GetClangFullType())) 233 { 234 // The dynamic type we found was the same type, 235 // so we don't have a dynamic type here... 236 return false; 237 } 238 } 239 240 // The offset_to_top is two pointers above the address. 241 Address offset_to_top_address = address_point_address; 242 int64_t slide = -2 * ((int64_t) target->GetArchitecture().GetAddressByteSize()); 243 offset_to_top_address.Slide (slide); 244 245 Error error; 246 lldb::addr_t offset_to_top_location = offset_to_top_address.GetLoadAddress(target); 247 248 size_t bytes_read = process->ReadMemory (offset_to_top_location, 249 memory_buffer, 250 address_byte_size, 251 error); 252 253 if (!error.Success() || (bytes_read != address_byte_size)) 254 { 255 return false; 256 } 257 258 offset = 0; 259 int64_t offset_to_top = data.GetMaxS64(&offset, process->GetAddressByteSize()); 260 261 // So the dynamic type is a value that starts at offset_to_top 262 // above the original address. 263 lldb::addr_t dynamic_addr = original_ptr + offset_to_top; 264 if (!target->GetSectionLoadList().ResolveLoadAddress (dynamic_addr, dynamic_address)) 265 { 266 dynamic_address.SetRawAddress(dynamic_addr); 267 } 268 return true; 269 } 270 } 271 } 272 } 273 } 274 } 275 276 return class_type_or_name.IsEmpty() == false; 277 } 278 279 bool 280 ItaniumABILanguageRuntime::IsVTableName (const char *name) 281 { 282 if (name == NULL) 283 return false; 284 285 // Can we maybe ask Clang about this? 286 if (strstr (name, "_vptr$") == name) 287 return true; 288 else 289 return false; 290 } 291 292 //------------------------------------------------------------------ 293 // Static Functions 294 //------------------------------------------------------------------ 295 LanguageRuntime * 296 ItaniumABILanguageRuntime::CreateInstance (Process *process, lldb::LanguageType language) 297 { 298 // FIXME: We have to check the process and make sure we actually know that this process supports 299 // the Itanium ABI. 300 if (language == eLanguageTypeC_plus_plus) 301 return new ItaniumABILanguageRuntime (process); 302 else 303 return NULL; 304 } 305 306 void 307 ItaniumABILanguageRuntime::Initialize() 308 { 309 PluginManager::RegisterPlugin (pluginName, 310 pluginDesc, 311 CreateInstance); 312 } 313 314 void 315 ItaniumABILanguageRuntime::Terminate() 316 { 317 PluginManager::UnregisterPlugin (CreateInstance); 318 } 319 320 //------------------------------------------------------------------ 321 // PluginInterface protocol 322 //------------------------------------------------------------------ 323 const char * 324 ItaniumABILanguageRuntime::GetPluginName() 325 { 326 return pluginName; 327 } 328 329 const char * 330 ItaniumABILanguageRuntime::GetShortPluginName() 331 { 332 return pluginShort; 333 } 334 335 uint32_t 336 ItaniumABILanguageRuntime::GetPluginVersion() 337 { 338 return 1; 339 } 340 341 BreakpointResolverSP 342 ItaniumABILanguageRuntime::CreateExceptionResolver (Breakpoint *bkpt, bool catch_bp, bool throw_bp) 343 { 344 return CreateExceptionResolver (bkpt, catch_bp, throw_bp, false); 345 } 346 347 BreakpointResolverSP 348 ItaniumABILanguageRuntime::CreateExceptionResolver (Breakpoint *bkpt, bool catch_bp, bool throw_bp, bool for_expressions) 349 { 350 // One complication here is that most users DON'T want to stop at __cxa_allocate_expression, but until we can do 351 // anything better with predicting unwinding the expression parser does. So we have two forms of the exception 352 // breakpoints, one for expressions that leaves out __cxa_allocate_exception, and one that includes it. 353 // The SetExceptionBreakpoints does the latter, the CreateExceptionBreakpoint in the runtime the former. 354 static const char *g_catch_name = "__cxa_begin_catch"; 355 static const char *g_throw_name1 = "__cxa_throw"; 356 static const char *g_throw_name2 = "__cxa_rethrow"; 357 static const char *g_exception_throw_name = "__cxa_allocate_exception"; 358 std::vector<const char *> exception_names; 359 exception_names.reserve(4); 360 if (catch_bp) 361 exception_names.push_back(g_catch_name); 362 363 if (throw_bp) 364 { 365 exception_names.push_back(g_throw_name1); 366 exception_names.push_back(g_throw_name2); 367 } 368 369 if (for_expressions) 370 exception_names.push_back(g_exception_throw_name); 371 372 BreakpointResolverSP resolver_sp (new BreakpointResolverName (bkpt, 373 exception_names.data(), 374 exception_names.size(), 375 eFunctionNameTypeBase, 376 eLazyBoolNo)); 377 378 return resolver_sp; 379 } 380 381 382 383 lldb::SearchFilterSP 384 ItaniumABILanguageRuntime::CreateExceptionSearchFilter () 385 { 386 Target &target = m_process->GetTarget(); 387 388 if (target.GetArchitecture().GetTriple().getVendor() == llvm::Triple::Apple) 389 { 390 // Limit the number of modules that are searched for these breakpoints for 391 // Apple binaries. 392 FileSpecList filter_modules; 393 filter_modules.Append(FileSpec("libc++abi.dylib", false)); 394 filter_modules.Append(FileSpec("libSystem.B.dylib", false)); 395 return target.GetSearchFilterForModuleList(&filter_modules); 396 } 397 else 398 { 399 return LanguageRuntime::CreateExceptionSearchFilter(); 400 } 401 } 402 403 lldb::BreakpointSP 404 ItaniumABILanguageRuntime::CreateExceptionBreakpoint (bool catch_bp, 405 bool throw_bp, 406 bool for_expressions, 407 bool is_internal) 408 { 409 Target &target = m_process->GetTarget(); 410 FileSpecList filter_modules; 411 BreakpointResolverSP exception_resolver_sp = CreateExceptionResolver (NULL, catch_bp, throw_bp, for_expressions); 412 SearchFilterSP filter_sp (CreateExceptionSearchFilter ()); 413 return target.CreateBreakpoint (filter_sp, exception_resolver_sp, is_internal); 414 } 415 416 void 417 ItaniumABILanguageRuntime::SetExceptionBreakpoints () 418 { 419 if (!m_process) 420 return; 421 422 const bool catch_bp = false; 423 const bool throw_bp = true; 424 const bool is_internal = true; 425 const bool for_expressions = true; 426 427 // For the exception breakpoints set by the Expression parser, we'll be a little more aggressive and 428 // stop at exception allocation as well. 429 430 if (m_cxx_exception_bp_sp) 431 { 432 m_cxx_exception_bp_sp->SetEnabled (true); 433 } 434 else 435 { 436 m_cxx_exception_bp_sp = CreateExceptionBreakpoint (catch_bp, throw_bp, for_expressions, is_internal); 437 if (m_cxx_exception_bp_sp) 438 m_cxx_exception_bp_sp->SetBreakpointKind("c++ exception"); 439 } 440 441 } 442 443 void 444 ItaniumABILanguageRuntime::ClearExceptionBreakpoints () 445 { 446 if (!m_process) 447 return; 448 449 if (m_cxx_exception_bp_sp) 450 { 451 m_cxx_exception_bp_sp->SetEnabled (false); 452 } 453 } 454 455 bool 456 ItaniumABILanguageRuntime::ExceptionBreakpointsExplainStop (lldb::StopInfoSP stop_reason) 457 { 458 if (!m_process) 459 return false; 460 461 if (!stop_reason || 462 stop_reason->GetStopReason() != eStopReasonBreakpoint) 463 return false; 464 465 uint64_t break_site_id = stop_reason->GetValue(); 466 return m_process->GetBreakpointSiteList().BreakpointSiteContainsBreakpoint(break_site_id, 467 m_cxx_exception_bp_sp->GetID()); 468 469 } 470