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/Module.h" 16 #include "lldb/Core/PluginManager.h" 17 #include "lldb/Core/Scalar.h" 18 #include "lldb/Core/ValueObject.h" 19 #include "lldb/Core/ValueObjectMemory.h" 20 #include "lldb/Symbol/ClangASTContext.h" 21 #include "lldb/Target/Process.h" 22 #include "lldb/Target/RegisterContext.h" 23 #include "lldb/Target/StopInfo.h" 24 #include "lldb/Target/Target.h" 25 #include "lldb/Target/Thread.h" 26 27 #include <vector> 28 29 using namespace lldb; 30 using namespace lldb_private; 31 32 static const char *pluginName = "ItaniumABILanguageRuntime"; 33 static const char *pluginDesc = "Itanium ABI for the C++ language"; 34 static const char *pluginShort = "language.itanium"; 35 static const char *vtable_demangled_prefix = "vtable for "; 36 37 bool 38 ItaniumABILanguageRuntime::CouldHaveDynamicValue (ValueObject &in_value) 39 { 40 return in_value.IsPossibleCPlusPlusDynamicType(); 41 } 42 43 bool 44 ItaniumABILanguageRuntime::GetDynamicTypeAndAddress (ValueObject &in_value, 45 lldb::DynamicValueType use_dynamic, 46 TypeAndOrName &class_type_or_name, 47 Address &dynamic_address) 48 { 49 // For Itanium, if the type has a vtable pointer in the object, it will be at offset 0 50 // in the object. That will point to the "address point" within the vtable (not the beginning of the 51 // vtable.) We can then look up the symbol containing this "address point" and that symbol's name 52 // demangled will contain the full class name. 53 // The second pointer above the "address point" is the "offset_to_top". We'll use that to get the 54 // start of the value object which holds the dynamic type. 55 // 56 57 // Only a pointer or reference type can have a different dynamic and static type: 58 if (CouldHaveDynamicValue (in_value)) 59 { 60 // FIXME: Can we get the Clang Type and ask it if the thing is really virtual? That would avoid false positives, 61 // at the cost of not looking for the dynamic type of objects if DWARF->Clang gets it wrong. 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 Target *target = in_value.GetUpdatePoint().GetTargetSP().get(); 70 Process *process = in_value.GetUpdatePoint().GetProcessSP().get(); 71 72 char memory_buffer[16]; 73 DataExtractor data(memory_buffer, sizeof(memory_buffer), 74 process->GetByteOrder(), 75 process->GetAddressByteSize()); 76 size_t address_byte_size = process->GetAddressByteSize(); 77 Error error; 78 size_t bytes_read = process->ReadMemory (original_ptr, 79 memory_buffer, 80 address_byte_size, 81 error); 82 if (!error.Success() || (bytes_read != address_byte_size)) 83 { 84 return false; 85 } 86 87 uint32_t offset_ptr = 0; 88 lldb::addr_t vtable_address_point = data.GetAddress (&offset_ptr); 89 90 if (offset_ptr == 0) 91 return false; 92 93 // Now find the symbol that contains this address: 94 95 SymbolContext sc; 96 Address address_point_address; 97 if (target && !target->GetSectionLoadList().IsEmpty()) 98 { 99 if (target->GetSectionLoadList().ResolveLoadAddress (vtable_address_point, address_point_address)) 100 { 101 target->GetImages().ResolveSymbolContextForAddress (address_point_address, eSymbolContextSymbol, sc); 102 Symbol *symbol = sc.symbol; 103 if (symbol != NULL) 104 { 105 const char *name = symbol->GetMangled().GetDemangledName().AsCString(); 106 if (strstr(name, vtable_demangled_prefix) == name) 107 { 108 // We are a C++ class, that's good. Get the class name and look it up: 109 const char *class_name = name + strlen(vtable_demangled_prefix); 110 class_type_or_name.SetName (class_name); 111 TypeList class_types; 112 uint32_t num_matches = target->GetImages().FindTypes (sc, 113 ConstString(class_name), 114 true, 115 UINT32_MAX, 116 class_types); 117 if (num_matches == 1) 118 { 119 class_type_or_name.SetTypeSP(class_types.GetTypeAtIndex(0)); 120 } 121 else if (num_matches > 1) 122 { 123 for (size_t i = 0; i < num_matches; i++) 124 { 125 lldb::TypeSP this_type(class_types.GetTypeAtIndex(i)); 126 if (this_type) 127 { 128 if (ClangASTContext::IsCXXClassType(this_type->GetClangFullType())) 129 { 130 // There can only be one type with a given name, 131 // so we've just found duplicate definitions, and this 132 // one will do as well as any other. 133 // We don't consider something to have a dynamic type if 134 // it is the same as the static type. So compare against 135 // the value we were handed: 136 137 clang::ASTContext *in_ast_ctx = in_value.GetClangAST (); 138 clang::ASTContext *this_ast_ctx = this_type->GetClangAST (); 139 if (in_ast_ctx != this_ast_ctx 140 || !ClangASTContext::AreTypesSame (in_ast_ctx, 141 in_value.GetClangType(), 142 this_type->GetClangFullType())) 143 { 144 class_type_or_name.SetTypeSP (this_type); 145 return true; 146 } 147 return false; 148 } 149 } 150 } 151 } 152 else 153 return false; 154 155 // The offset_to_top is two pointers above the address. 156 Address offset_to_top_address = address_point_address; 157 int64_t slide = -2 * ((int64_t) target->GetArchitecture().GetAddressByteSize()); 158 offset_to_top_address.Slide (slide); 159 160 Error error; 161 lldb::addr_t offset_to_top_location = offset_to_top_address.GetLoadAddress(target); 162 163 size_t bytes_read = process->ReadMemory (offset_to_top_location, 164 memory_buffer, 165 address_byte_size, 166 error); 167 168 if (!error.Success() || (bytes_read != address_byte_size)) 169 { 170 return false; 171 } 172 173 offset_ptr = 0; 174 int64_t offset_to_top = data.GetMaxS64(&offset_ptr, process->GetAddressByteSize()); 175 176 // So the dynamic type is a value that starts at offset_to_top 177 // above the original address. 178 lldb::addr_t dynamic_addr = original_ptr + offset_to_top; 179 if (!target->GetSectionLoadList().ResolveLoadAddress (dynamic_addr, dynamic_address)) 180 { 181 dynamic_address.SetOffset(dynamic_addr); 182 dynamic_address.SetSection(NULL); 183 } 184 return true; 185 } 186 } 187 } 188 } 189 190 } 191 192 return false; 193 } 194 195 bool 196 ItaniumABILanguageRuntime::IsVTableName (const char *name) 197 { 198 if (name == NULL) 199 return false; 200 201 // Can we maybe ask Clang about this? 202 if (strstr (name, "_vptr$") == name) 203 return true; 204 else 205 return false; 206 } 207 208 //------------------------------------------------------------------ 209 // Static Functions 210 //------------------------------------------------------------------ 211 lldb_private::LanguageRuntime * 212 ItaniumABILanguageRuntime::CreateInstance (Process *process, lldb::LanguageType language) 213 { 214 // FIXME: We have to check the process and make sure we actually know that this process supports 215 // the Itanium ABI. 216 if (language == eLanguageTypeC_plus_plus) 217 return new ItaniumABILanguageRuntime (process); 218 else 219 return NULL; 220 } 221 222 void 223 ItaniumABILanguageRuntime::Initialize() 224 { 225 PluginManager::RegisterPlugin (pluginName, 226 pluginDesc, 227 CreateInstance); 228 } 229 230 void 231 ItaniumABILanguageRuntime::Terminate() 232 { 233 PluginManager::UnregisterPlugin (CreateInstance); 234 } 235 236 //------------------------------------------------------------------ 237 // PluginInterface protocol 238 //------------------------------------------------------------------ 239 const char * 240 ItaniumABILanguageRuntime::GetPluginName() 241 { 242 return pluginName; 243 } 244 245 const char * 246 ItaniumABILanguageRuntime::GetShortPluginName() 247 { 248 return pluginShort; 249 } 250 251 uint32_t 252 ItaniumABILanguageRuntime::GetPluginVersion() 253 { 254 return 1; 255 } 256 257 void 258 ItaniumABILanguageRuntime::SetExceptionBreakpoints () 259 { 260 if (!m_process) 261 return; 262 263 if (!m_cxx_exception_bp_sp) 264 m_cxx_exception_bp_sp = m_process->GetTarget().CreateBreakpoint (NULL, 265 NULL, 266 "__cxa_throw", 267 eFunctionNameTypeBase, 268 true); 269 else 270 m_cxx_exception_bp_sp->SetEnabled (true); 271 272 if (!m_cxx_exception_alloc_bp_sp) 273 m_cxx_exception_alloc_bp_sp = m_process->GetTarget().CreateBreakpoint (NULL, 274 NULL, 275 "__cxa_allocate", 276 eFunctionNameTypeBase, 277 true); 278 else 279 m_cxx_exception_alloc_bp_sp->SetEnabled (true); 280 } 281 282 void 283 ItaniumABILanguageRuntime::ClearExceptionBreakpoints () 284 { 285 if (!m_process) 286 return; 287 288 if (m_cxx_exception_bp_sp.get()) 289 { 290 m_cxx_exception_bp_sp->SetEnabled (false); 291 } 292 293 if (m_cxx_exception_alloc_bp_sp.get()) 294 { 295 m_cxx_exception_bp_sp->SetEnabled (false); 296 } 297 } 298 299 bool 300 ItaniumABILanguageRuntime::ExceptionBreakpointsExplainStop (lldb::StopInfoSP stop_reason) 301 { 302 if (!m_process) 303 return false; 304 305 if (!stop_reason || 306 stop_reason->GetStopReason() != eStopReasonBreakpoint) 307 return false; 308 309 uint64_t break_site_id = stop_reason->GetValue(); 310 lldb::BreakpointSiteSP bp_site_sp = m_process->GetBreakpointSiteList().FindByID(break_site_id); 311 312 if (!bp_site_sp) 313 return false; 314 315 uint32_t num_owners = bp_site_sp->GetNumberOfOwners(); 316 317 bool check_cxx_exception = false; 318 break_id_t cxx_exception_bid; 319 320 bool check_cxx_exception_alloc = false; 321 break_id_t cxx_exception_alloc_bid; 322 323 if (m_cxx_exception_bp_sp) 324 { 325 check_cxx_exception = true; 326 cxx_exception_bid = m_cxx_exception_bp_sp->GetID(); 327 } 328 329 if (m_cxx_exception_alloc_bp_sp) 330 { 331 check_cxx_exception_alloc = true; 332 cxx_exception_alloc_bid = m_cxx_exception_alloc_bp_sp->GetID(); 333 } 334 335 for (uint32_t i = 0; i < num_owners; i++) 336 { 337 break_id_t bid = bp_site_sp->GetOwnerAtIndex(i)->GetBreakpoint().GetID(); 338 339 if ((check_cxx_exception && (bid == cxx_exception_bid)) || 340 (check_cxx_exception_alloc && (bid == cxx_exception_alloc_bid))) 341 return true; 342 } 343 344 return false; 345 } 346