1 //===-- JITLoaderGDB.cpp --------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "JITLoaderGDB.h" 10 #ifdef LLDB_ENABLE_ALL 11 #include "Plugins/ObjectFile/Mach-O/ObjectFileMachO.h" 12 #endif // LLDB_ENABLE_ALL 13 #include "lldb/Breakpoint/Breakpoint.h" 14 #include "lldb/Core/Module.h" 15 #include "lldb/Core/ModuleSpec.h" 16 #include "lldb/Core/PluginManager.h" 17 #include "lldb/Core/Section.h" 18 #include "lldb/Interpreter/OptionValueProperties.h" 19 #include "lldb/Symbol/ObjectFile.h" 20 #include "lldb/Symbol/Symbol.h" 21 #include "lldb/Symbol/SymbolContext.h" 22 #include "lldb/Symbol/SymbolVendor.h" 23 #include "lldb/Target/Process.h" 24 #include "lldb/Target/SectionLoadList.h" 25 #include "lldb/Target/Target.h" 26 #include "lldb/Utility/DataBufferHeap.h" 27 #include "lldb/Utility/LLDBAssert.h" 28 #include "lldb/Utility/Log.h" 29 #include "lldb/Utility/StreamString.h" 30 #include "llvm/Support/MathExtras.h" 31 32 #include <memory> 33 34 using namespace lldb; 35 using namespace lldb_private; 36 37 LLDB_PLUGIN_DEFINE(JITLoaderGDB) 38 39 // Debug Interface Structures 40 enum jit_actions_t { JIT_NOACTION = 0, JIT_REGISTER_FN, JIT_UNREGISTER_FN }; 41 42 template <typename ptr_t> struct jit_code_entry { 43 ptr_t next_entry; // pointer 44 ptr_t prev_entry; // pointer 45 ptr_t symfile_addr; // pointer 46 uint64_t symfile_size; 47 }; 48 49 template <typename ptr_t> struct jit_descriptor { 50 uint32_t version; 51 uint32_t action_flag; // Values are jit_action_t 52 ptr_t relevant_entry; // pointer 53 ptr_t first_entry; // pointer 54 }; 55 56 namespace { 57 58 enum EnableJITLoaderGDB { 59 eEnableJITLoaderGDBDefault, 60 eEnableJITLoaderGDBOn, 61 eEnableJITLoaderGDBOff, 62 }; 63 64 static constexpr OptionEnumValueElement g_enable_jit_loader_gdb_enumerators[] = 65 { 66 { 67 eEnableJITLoaderGDBDefault, 68 "default", 69 "Enable JIT compilation interface for all platforms except macOS", 70 }, 71 { 72 eEnableJITLoaderGDBOn, 73 "on", 74 "Enable JIT compilation interface", 75 }, 76 { 77 eEnableJITLoaderGDBOff, 78 "off", 79 "Disable JIT compilation interface", 80 }, 81 }; 82 83 #define LLDB_PROPERTIES_jitloadergdb 84 #include "JITLoaderGDBProperties.inc" 85 86 enum { 87 #define LLDB_PROPERTIES_jitloadergdb 88 #include "JITLoaderGDBPropertiesEnum.inc" 89 ePropertyEnableJITBreakpoint 90 }; 91 92 class PluginProperties : public Properties { 93 public: 94 static ConstString GetSettingName() { 95 return ConstString(JITLoaderGDB::GetPluginNameStatic()); 96 } 97 98 PluginProperties() { 99 m_collection_sp = std::make_shared<OptionValueProperties>(GetSettingName()); 100 m_collection_sp->Initialize(g_jitloadergdb_properties); 101 } 102 103 EnableJITLoaderGDB GetEnable() const { 104 return (EnableJITLoaderGDB)m_collection_sp->GetPropertyAtIndexAsEnumeration( 105 nullptr, ePropertyEnable, 106 g_jitloadergdb_properties[ePropertyEnable].default_uint_value); 107 } 108 }; 109 110 static PluginProperties &GetGlobalPluginProperties() { 111 static PluginProperties g_settings; 112 return g_settings; 113 } 114 115 template <typename ptr_t> 116 bool ReadJITEntry(const addr_t from_addr, Process *process, 117 jit_code_entry<ptr_t> *entry) { 118 lldbassert(from_addr % sizeof(ptr_t) == 0); 119 120 ArchSpec::Core core = process->GetTarget().GetArchitecture().GetCore(); 121 bool i386_target = ArchSpec::kCore_x86_32_first <= core && 122 core <= ArchSpec::kCore_x86_32_last; 123 uint8_t uint64_align_bytes = i386_target ? 4 : 8; 124 const size_t data_byte_size = 125 llvm::alignTo(sizeof(ptr_t) * 3, uint64_align_bytes) + sizeof(uint64_t); 126 127 Status error; 128 DataBufferHeap data(data_byte_size, 0); 129 size_t bytes_read = process->ReadMemory(from_addr, data.GetBytes(), 130 data.GetByteSize(), error); 131 if (bytes_read != data_byte_size || !error.Success()) 132 return false; 133 134 DataExtractor extractor(data.GetBytes(), data.GetByteSize(), 135 process->GetByteOrder(), sizeof(ptr_t)); 136 lldb::offset_t offset = 0; 137 entry->next_entry = extractor.GetAddress(&offset); 138 entry->prev_entry = extractor.GetAddress(&offset); 139 entry->symfile_addr = extractor.GetAddress(&offset); 140 offset = llvm::alignTo(offset, uint64_align_bytes); 141 entry->symfile_size = extractor.GetU64(&offset); 142 143 return true; 144 } 145 146 } // anonymous namespace end 147 148 JITLoaderGDB::JITLoaderGDB(lldb_private::Process *process) 149 : JITLoader(process), m_jit_objects(), 150 m_jit_break_id(LLDB_INVALID_BREAK_ID), 151 m_jit_descriptor_addr(LLDB_INVALID_ADDRESS) {} 152 153 JITLoaderGDB::~JITLoaderGDB() { 154 if (LLDB_BREAK_ID_IS_VALID(m_jit_break_id)) 155 m_process->GetTarget().RemoveBreakpointByID(m_jit_break_id); 156 } 157 158 void JITLoaderGDB::DebuggerInitialize(Debugger &debugger) { 159 if (!PluginManager::GetSettingForJITLoaderPlugin( 160 debugger, PluginProperties::GetSettingName())) { 161 const bool is_global_setting = true; 162 PluginManager::CreateSettingForJITLoaderPlugin( 163 debugger, GetGlobalPluginProperties().GetValueProperties(), 164 ConstString("Properties for the JIT LoaderGDB plug-in."), 165 is_global_setting); 166 } 167 } 168 169 void JITLoaderGDB::DidAttach() { 170 Target &target = m_process->GetTarget(); 171 ModuleList &module_list = target.GetImages(); 172 SetJITBreakpoint(module_list); 173 } 174 175 void JITLoaderGDB::DidLaunch() { 176 Target &target = m_process->GetTarget(); 177 ModuleList &module_list = target.GetImages(); 178 SetJITBreakpoint(module_list); 179 } 180 181 void JITLoaderGDB::ModulesDidLoad(ModuleList &module_list) { 182 if (!DidSetJITBreakpoint() && m_process->IsAlive()) 183 SetJITBreakpoint(module_list); 184 } 185 186 // Setup the JIT Breakpoint 187 void JITLoaderGDB::SetJITBreakpoint(lldb_private::ModuleList &module_list) { 188 if (DidSetJITBreakpoint()) 189 return; 190 191 Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_JIT_LOADER)); 192 LLDB_LOGF(log, "JITLoaderGDB::%s looking for JIT register hook", 193 __FUNCTION__); 194 195 addr_t jit_addr = GetSymbolAddress( 196 module_list, ConstString("__jit_debug_register_code"), eSymbolTypeAny); 197 if (jit_addr == LLDB_INVALID_ADDRESS) 198 return; 199 200 m_jit_descriptor_addr = GetSymbolAddress( 201 module_list, ConstString("__jit_debug_descriptor"), eSymbolTypeData); 202 if (m_jit_descriptor_addr == LLDB_INVALID_ADDRESS) { 203 LLDB_LOGF(log, "JITLoaderGDB::%s failed to find JIT descriptor address", 204 __FUNCTION__); 205 return; 206 } 207 208 LLDB_LOGF(log, "JITLoaderGDB::%s setting JIT breakpoint", __FUNCTION__); 209 210 Breakpoint *bp = 211 m_process->GetTarget().CreateBreakpoint(jit_addr, true, false).get(); 212 bp->SetCallback(JITDebugBreakpointHit, this, true); 213 bp->SetBreakpointKind("jit-debug-register"); 214 m_jit_break_id = bp->GetID(); 215 216 ReadJITDescriptor(true); 217 } 218 219 bool JITLoaderGDB::JITDebugBreakpointHit(void *baton, 220 StoppointCallbackContext *context, 221 user_id_t break_id, 222 user_id_t break_loc_id) { 223 Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_JIT_LOADER)); 224 LLDB_LOGF(log, "JITLoaderGDB::%s hit JIT breakpoint", __FUNCTION__); 225 JITLoaderGDB *instance = static_cast<JITLoaderGDB *>(baton); 226 return instance->ReadJITDescriptor(false); 227 } 228 229 static void updateSectionLoadAddress(const SectionList §ion_list, 230 Target &target, uint64_t symbolfile_addr, 231 uint64_t symbolfile_size, 232 uint64_t &vmaddrheuristic, 233 uint64_t &min_addr, uint64_t &max_addr) { 234 const uint32_t num_sections = section_list.GetSize(); 235 for (uint32_t i = 0; i < num_sections; ++i) { 236 SectionSP section_sp(section_list.GetSectionAtIndex(i)); 237 if (section_sp) { 238 if (section_sp->IsFake()) { 239 uint64_t lower = (uint64_t)-1; 240 uint64_t upper = 0; 241 updateSectionLoadAddress(section_sp->GetChildren(), target, 242 symbolfile_addr, symbolfile_size, 243 vmaddrheuristic, lower, upper); 244 if (lower < min_addr) 245 min_addr = lower; 246 if (upper > max_addr) 247 max_addr = upper; 248 const lldb::addr_t slide_amount = lower - section_sp->GetFileAddress(); 249 section_sp->Slide(slide_amount, false); 250 section_sp->GetChildren().Slide(-slide_amount, false); 251 section_sp->SetByteSize(upper - lower); 252 } else { 253 vmaddrheuristic += 2 << section_sp->GetLog2Align(); 254 uint64_t lower; 255 if (section_sp->GetFileAddress() > vmaddrheuristic) 256 lower = section_sp->GetFileAddress(); 257 else { 258 lower = symbolfile_addr + section_sp->GetFileOffset(); 259 section_sp->SetFileAddress(symbolfile_addr + 260 section_sp->GetFileOffset()); 261 } 262 target.SetSectionLoadAddress(section_sp, lower, true); 263 uint64_t upper = lower + section_sp->GetByteSize(); 264 if (lower < min_addr) 265 min_addr = lower; 266 if (upper > max_addr) 267 max_addr = upper; 268 // This is an upper bound, but a good enough heuristic 269 vmaddrheuristic += section_sp->GetByteSize(); 270 } 271 } 272 } 273 } 274 275 bool JITLoaderGDB::ReadJITDescriptor(bool all_entries) { 276 if (m_process->GetTarget().GetArchitecture().GetAddressByteSize() == 8) 277 return ReadJITDescriptorImpl<uint64_t>(all_entries); 278 else 279 return ReadJITDescriptorImpl<uint32_t>(all_entries); 280 } 281 282 template <typename ptr_t> 283 bool JITLoaderGDB::ReadJITDescriptorImpl(bool all_entries) { 284 if (m_jit_descriptor_addr == LLDB_INVALID_ADDRESS) 285 return false; 286 287 Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_JIT_LOADER)); 288 Target &target = m_process->GetTarget(); 289 ModuleList &module_list = target.GetImages(); 290 291 jit_descriptor<ptr_t> jit_desc; 292 const size_t jit_desc_size = sizeof(jit_desc); 293 Status error; 294 size_t bytes_read = m_process->ReadMemory(m_jit_descriptor_addr, &jit_desc, 295 jit_desc_size, error); 296 if (bytes_read != jit_desc_size || !error.Success()) { 297 LLDB_LOGF(log, "JITLoaderGDB::%s failed to read JIT descriptor", 298 __FUNCTION__); 299 return false; 300 } 301 302 jit_actions_t jit_action = (jit_actions_t)jit_desc.action_flag; 303 addr_t jit_relevant_entry = (addr_t)jit_desc.relevant_entry; 304 if (all_entries) { 305 jit_action = JIT_REGISTER_FN; 306 jit_relevant_entry = (addr_t)jit_desc.first_entry; 307 } 308 309 while (jit_relevant_entry != 0) { 310 jit_code_entry<ptr_t> jit_entry; 311 if (!ReadJITEntry(jit_relevant_entry, m_process, &jit_entry)) { 312 LLDB_LOGF(log, "JITLoaderGDB::%s failed to read JIT entry at 0x%" PRIx64, 313 __FUNCTION__, jit_relevant_entry); 314 return false; 315 } 316 317 const addr_t &symbolfile_addr = (addr_t)jit_entry.symfile_addr; 318 const size_t &symbolfile_size = (size_t)jit_entry.symfile_size; 319 ModuleSP module_sp; 320 321 if (jit_action == JIT_REGISTER_FN) { 322 LLDB_LOGF(log, 323 "JITLoaderGDB::%s registering JIT entry at 0x%" PRIx64 324 " (%" PRIu64 " bytes)", 325 __FUNCTION__, symbolfile_addr, (uint64_t)symbolfile_size); 326 327 char jit_name[64]; 328 snprintf(jit_name, 64, "JIT(0x%" PRIx64 ")", symbolfile_addr); 329 module_sp = m_process->ReadModuleFromMemory( 330 FileSpec(jit_name), symbolfile_addr, symbolfile_size); 331 332 if (module_sp && module_sp->GetObjectFile()) { 333 // Object formats (like ELF) have no representation for a JIT type. 334 // We will get it wrong, if we deduce it from the header. 335 module_sp->GetObjectFile()->SetType(ObjectFile::eTypeJIT); 336 337 // load the symbol table right away 338 module_sp->GetObjectFile()->GetSymtab(); 339 340 m_jit_objects.insert(std::make_pair(symbolfile_addr, module_sp)); 341 #ifdef LLDB_ENABLE_ALL 342 if (auto image_object_file = 343 llvm::dyn_cast<ObjectFileMachO>(module_sp->GetObjectFile())) { 344 const SectionList *section_list = image_object_file->GetSectionList(); 345 if (section_list) { 346 uint64_t vmaddrheuristic = 0; 347 uint64_t lower = (uint64_t)-1; 348 uint64_t upper = 0; 349 updateSectionLoadAddress(*section_list, target, symbolfile_addr, 350 symbolfile_size, vmaddrheuristic, lower, 351 upper); 352 } 353 } else 354 #endif // LLDB_ENABLE_ALL 355 { 356 bool changed = false; 357 module_sp->SetLoadAddress(target, 0, true, changed); 358 } 359 360 module_list.AppendIfNeeded(module_sp); 361 362 ModuleList module_list; 363 module_list.Append(module_sp); 364 target.ModulesDidLoad(module_list); 365 } else { 366 LLDB_LOGF(log, 367 "JITLoaderGDB::%s failed to load module for " 368 "JIT entry at 0x%" PRIx64, 369 __FUNCTION__, symbolfile_addr); 370 } 371 } else if (jit_action == JIT_UNREGISTER_FN) { 372 LLDB_LOGF(log, "JITLoaderGDB::%s unregistering JIT entry at 0x%" PRIx64, 373 __FUNCTION__, symbolfile_addr); 374 375 JITObjectMap::iterator it = m_jit_objects.find(symbolfile_addr); 376 if (it != m_jit_objects.end()) { 377 module_sp = it->second; 378 ObjectFile *image_object_file = module_sp->GetObjectFile(); 379 if (image_object_file) { 380 const SectionList *section_list = image_object_file->GetSectionList(); 381 if (section_list) { 382 const uint32_t num_sections = section_list->GetSize(); 383 for (uint32_t i = 0; i < num_sections; ++i) { 384 SectionSP section_sp(section_list->GetSectionAtIndex(i)); 385 if (section_sp) { 386 target.GetSectionLoadList().SetSectionUnloaded(section_sp); 387 } 388 } 389 } 390 } 391 module_list.Remove(module_sp); 392 m_jit_objects.erase(it); 393 } 394 } else if (jit_action == JIT_NOACTION) { 395 // Nothing to do 396 } else { 397 assert(false && "Unknown jit action"); 398 } 399 400 if (all_entries) 401 jit_relevant_entry = (addr_t)jit_entry.next_entry; 402 else 403 jit_relevant_entry = 0; 404 } 405 406 return false; // Continue Running. 407 } 408 409 // PluginInterface protocol 410 JITLoaderSP JITLoaderGDB::CreateInstance(Process *process, bool force) { 411 JITLoaderSP jit_loader_sp; 412 bool enable; 413 switch (GetGlobalPluginProperties().GetEnable()) { 414 case EnableJITLoaderGDB::eEnableJITLoaderGDBOn: 415 enable = true; 416 break; 417 case EnableJITLoaderGDB::eEnableJITLoaderGDBOff: 418 enable = false; 419 break; 420 case EnableJITLoaderGDB::eEnableJITLoaderGDBDefault: 421 ArchSpec arch(process->GetTarget().GetArchitecture()); 422 enable = arch.GetTriple().getVendor() != llvm::Triple::Apple; 423 break; 424 } 425 if (enable) 426 jit_loader_sp = std::make_shared<JITLoaderGDB>(process); 427 return jit_loader_sp; 428 } 429 430 llvm::StringRef JITLoaderGDB::GetPluginDescriptionStatic() { 431 return "JIT loader plug-in that watches for JIT events using the GDB " 432 "interface."; 433 } 434 435 void JITLoaderGDB::Initialize() { 436 PluginManager::RegisterPlugin(GetPluginNameStatic(), 437 GetPluginDescriptionStatic(), CreateInstance, 438 DebuggerInitialize); 439 } 440 441 void JITLoaderGDB::Terminate() { 442 PluginManager::UnregisterPlugin(CreateInstance); 443 } 444 445 bool JITLoaderGDB::DidSetJITBreakpoint() const { 446 return LLDB_BREAK_ID_IS_VALID(m_jit_break_id); 447 } 448 449 addr_t JITLoaderGDB::GetSymbolAddress(ModuleList &module_list, 450 ConstString name, 451 SymbolType symbol_type) const { 452 SymbolContextList target_symbols; 453 Target &target = m_process->GetTarget(); 454 455 module_list.FindSymbolsWithNameAndType(name, symbol_type, target_symbols); 456 if (target_symbols.IsEmpty()) 457 return LLDB_INVALID_ADDRESS; 458 459 SymbolContext sym_ctx; 460 target_symbols.GetContextAtIndex(0, sym_ctx); 461 462 const Address jit_descriptor_addr = sym_ctx.symbol->GetAddress(); 463 if (!jit_descriptor_addr.IsValid()) 464 return LLDB_INVALID_ADDRESS; 465 466 const addr_t jit_addr = jit_descriptor_addr.GetLoadAddress(&target); 467 return jit_addr; 468 } 469