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