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