1 //===-- AppleObjCTrampolineHandler.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 "AppleObjCTrampolineHandler.h" 10 #include "AppleThreadPlanStepThroughObjCTrampoline.h" 11 12 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h" 13 #include "lldb/Breakpoint/StoppointCallbackContext.h" 14 #include "lldb/Core/Debugger.h" 15 #include "lldb/Core/Module.h" 16 #include "lldb/Core/StreamFile.h" 17 #include "lldb/Core/Value.h" 18 #include "lldb/Expression/DiagnosticManager.h" 19 #include "lldb/Expression/FunctionCaller.h" 20 #include "lldb/Expression/UserExpression.h" 21 #include "lldb/Expression/UtilityFunction.h" 22 #include "lldb/Symbol/Symbol.h" 23 #include "lldb/Target/ABI.h" 24 #include "lldb/Target/ExecutionContext.h" 25 #include "lldb/Target/Process.h" 26 #include "lldb/Target/RegisterContext.h" 27 #include "lldb/Target/Target.h" 28 #include "lldb/Target/Thread.h" 29 #include "lldb/Target/ThreadPlanRunToAddress.h" 30 #include "lldb/Utility/ConstString.h" 31 #include "lldb/Utility/FileSpec.h" 32 #include "lldb/Utility/Log.h" 33 34 #include "llvm/ADT/STLExtras.h" 35 36 #include "Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.h" 37 38 #include <memory> 39 40 using namespace lldb; 41 using namespace lldb_private; 42 43 const char *AppleObjCTrampolineHandler::g_lookup_implementation_function_name = 44 "__lldb_objc_find_implementation_for_selector"; 45 const char *AppleObjCTrampolineHandler:: 46 g_lookup_implementation_with_stret_function_code = 47 " \n\ 48 extern \"C\" \n\ 49 { \n\ 50 extern void *class_getMethodImplementation(void *objc_class, void *sel); \n\ 51 extern void *class_getMethodImplementation_stret(void *objc_class, \n\ 52 void *sel); \n\ 53 extern void * object_getClass (id object); \n\ 54 extern void * sel_getUid(char *name); \n\ 55 extern int printf(const char *format, ...); \n\ 56 } \n\ 57 extern \"C\" void * __lldb_objc_find_implementation_for_selector ( \n\ 58 void *object, \n\ 59 void *sel, \n\ 60 int is_stret, \n\ 61 int is_super, \n\ 62 int is_super2, \n\ 63 int is_fixup, \n\ 64 int is_fixed, \n\ 65 int debug) \n\ 66 { \n\ 67 struct __lldb_imp_return_struct \n\ 68 { \n\ 69 void *class_addr; \n\ 70 void *sel_addr; \n\ 71 void *impl_addr; \n\ 72 }; \n\ 73 \n\ 74 struct __lldb_objc_class { \n\ 75 void *isa; \n\ 76 void *super_ptr; \n\ 77 }; \n\ 78 struct __lldb_objc_super { \n\ 79 void *receiver; \n\ 80 struct __lldb_objc_class *class_ptr; \n\ 81 }; \n\ 82 struct __lldb_msg_ref { \n\ 83 void *dont_know; \n\ 84 void *sel; \n\ 85 }; \n\ 86 \n\ 87 struct __lldb_imp_return_struct return_struct; \n\ 88 \n\ 89 if (debug) \n\ 90 printf (\"\\n*** Called with obj: 0x%p sel: 0x%p is_stret: %d is_super: %d, \"\n\ 91 \"is_super2: %d, is_fixup: %d, is_fixed: %d\\n\", \n\ 92 object, sel, is_stret, is_super, is_super2, is_fixup, is_fixed);\n\ 93 if (is_super) \n\ 94 { \n\ 95 if (is_super2) \n\ 96 { \n\ 97 return_struct.class_addr = ((__lldb_objc_super *) object)->class_ptr->super_ptr;\n\ 98 } \n\ 99 else \n\ 100 { \n\ 101 return_struct.class_addr = ((__lldb_objc_super *) object)->class_ptr;\n\ 102 } \n\ 103 } \n\ 104 else \n\ 105 { \n\ 106 // This code seems a little funny, but has its reasons... \n\ 107 \n\ 108 // The call to [object class] is here because if this is a \n\ 109 // class, and has not been called into yet, we need to do \n\ 110 // something to force the class to initialize itself. \n\ 111 // Then the call to object_getClass will actually return the \n\ 112 // correct class, either the class if object is a class \n\ 113 // instance, or the meta-class if it is a class pointer. \n\ 114 void *class_ptr = (void *) [(id) object class]; \n\ 115 return_struct.class_addr = (id) object_getClass((id) object); \n\ 116 if (debug) \n\ 117 { \n\ 118 if (class_ptr == object) \n\ 119 { \n\ 120 printf (\"Found a class object, need to use the meta class %p -> %p\\n\",\n\ 121 class_ptr, return_struct.class_addr); \n\ 122 } \n\ 123 else \n\ 124 { \n\ 125 printf (\"[object class] returned: %p object_getClass: %p.\\n\", \n\ 126 class_ptr, return_struct.class_addr); \n\ 127 } \n\ 128 } \n\ 129 } \n\ 130 \n\ 131 if (is_fixup) \n\ 132 { \n\ 133 if (is_fixed) \n\ 134 { \n\ 135 return_struct.sel_addr = ((__lldb_msg_ref *) sel)->sel; \n\ 136 } \n\ 137 else \n\ 138 { \n\ 139 char *sel_name = (char *) ((__lldb_msg_ref *) sel)->sel; \n\ 140 return_struct.sel_addr = sel_getUid (sel_name); \n\ 141 if (debug) \n\ 142 printf (\"\\n*** Got fixed up selector: %p for name %s.\\n\",\n\ 143 return_struct.sel_addr, sel_name); \n\ 144 } \n\ 145 } \n\ 146 else \n\ 147 { \n\ 148 return_struct.sel_addr = sel; \n\ 149 } \n\ 150 \n\ 151 if (is_stret) \n\ 152 { \n\ 153 return_struct.impl_addr = \n\ 154 class_getMethodImplementation_stret (return_struct.class_addr, \n\ 155 return_struct.sel_addr); \n\ 156 } \n\ 157 else \n\ 158 { \n\ 159 return_struct.impl_addr = \n\ 160 class_getMethodImplementation (return_struct.class_addr, \n\ 161 return_struct.sel_addr); \n\ 162 } \n\ 163 if (debug) \n\ 164 printf (\"\\n*** Returning implementation: %p.\\n\", \n\ 165 return_struct.impl_addr); \n\ 166 \n\ 167 return return_struct.impl_addr; \n\ 168 } \n\ 169 "; 170 const char * 171 AppleObjCTrampolineHandler::g_lookup_implementation_no_stret_function_code = 172 " \n\ 173 extern \"C\" \n\ 174 { \n\ 175 extern void *class_getMethodImplementation(void *objc_class, void *sel); \n\ 176 extern void * object_getClass (id object); \n\ 177 extern void * sel_getUid(char *name); \n\ 178 extern int printf(const char *format, ...); \n\ 179 } \n\ 180 extern \"C\" void * __lldb_objc_find_implementation_for_selector (void *object, \n\ 181 void *sel, \n\ 182 int is_stret, \n\ 183 int is_super, \n\ 184 int is_super2, \n\ 185 int is_fixup, \n\ 186 int is_fixed, \n\ 187 int debug) \n\ 188 { \n\ 189 struct __lldb_imp_return_struct \n\ 190 { \n\ 191 void *class_addr; \n\ 192 void *sel_addr; \n\ 193 void *impl_addr; \n\ 194 }; \n\ 195 \n\ 196 struct __lldb_objc_class { \n\ 197 void *isa; \n\ 198 void *super_ptr; \n\ 199 }; \n\ 200 struct __lldb_objc_super { \n\ 201 void *receiver; \n\ 202 struct __lldb_objc_class *class_ptr; \n\ 203 }; \n\ 204 struct __lldb_msg_ref { \n\ 205 void *dont_know; \n\ 206 void *sel; \n\ 207 }; \n\ 208 \n\ 209 struct __lldb_imp_return_struct return_struct; \n\ 210 \n\ 211 if (debug) \n\ 212 printf (\"\\n*** Called with obj: 0x%p sel: 0x%p is_stret: %d is_super: %d, \" \n\ 213 \"is_super2: %d, is_fixup: %d, is_fixed: %d\\n\", \n\ 214 object, sel, is_stret, is_super, is_super2, is_fixup, is_fixed); \n\ 215 if (is_super) \n\ 216 { \n\ 217 if (is_super2) \n\ 218 { \n\ 219 return_struct.class_addr = ((__lldb_objc_super *) object)->class_ptr->super_ptr; \n\ 220 } \n\ 221 else \n\ 222 { \n\ 223 return_struct.class_addr = ((__lldb_objc_super *) object)->class_ptr; \n\ 224 } \n\ 225 } \n\ 226 else \n\ 227 { \n\ 228 // This code seems a little funny, but has its reasons... \n\ 229 // The call to [object class] is here because if this is a class, and has not been called into \n\ 230 // yet, we need to do something to force the class to initialize itself. \n\ 231 // Then the call to object_getClass will actually return the correct class, either the class \n\ 232 // if object is a class instance, or the meta-class if it is a class pointer. \n\ 233 void *class_ptr = (void *) [(id) object class]; \n\ 234 return_struct.class_addr = (id) object_getClass((id) object); \n\ 235 if (debug) \n\ 236 { \n\ 237 if (class_ptr == object) \n\ 238 { \n\ 239 printf (\"Found a class object, need to return the meta class %p -> %p\\n\", \n\ 240 class_ptr, return_struct.class_addr); \n\ 241 } \n\ 242 else \n\ 243 { \n\ 244 printf (\"[object class] returned: %p object_getClass: %p.\\n\", \n\ 245 class_ptr, return_struct.class_addr); \n\ 246 } \n\ 247 } \n\ 248 } \n\ 249 \n\ 250 if (is_fixup) \n\ 251 { \n\ 252 if (is_fixed) \n\ 253 { \n\ 254 return_struct.sel_addr = ((__lldb_msg_ref *) sel)->sel; \n\ 255 } \n\ 256 else \n\ 257 { \n\ 258 char *sel_name = (char *) ((__lldb_msg_ref *) sel)->sel; \n\ 259 return_struct.sel_addr = sel_getUid (sel_name); \n\ 260 if (debug) \n\ 261 printf (\"\\n*** Got fixed up selector: %p for name %s.\\n\",\n\ 262 return_struct.sel_addr, sel_name); \n\ 263 } \n\ 264 } \n\ 265 else \n\ 266 { \n\ 267 return_struct.sel_addr = sel; \n\ 268 } \n\ 269 \n\ 270 return_struct.impl_addr = \n\ 271 class_getMethodImplementation (return_struct.class_addr, \n\ 272 return_struct.sel_addr); \n\ 273 if (debug) \n\ 274 printf (\"\\n*** Returning implementation: 0x%p.\\n\", \n\ 275 return_struct.impl_addr); \n\ 276 \n\ 277 return return_struct.impl_addr; \n\ 278 } \n\ 279 "; 280 281 AppleObjCTrampolineHandler::AppleObjCVTables::VTableRegion::VTableRegion( 282 AppleObjCVTables *owner, lldb::addr_t header_addr) 283 : m_valid(true), m_owner(owner), m_header_addr(header_addr), 284 m_code_start_addr(0), m_code_end_addr(0), m_next_region(0) { 285 SetUpRegion(); 286 } 287 288 AppleObjCTrampolineHandler::~AppleObjCTrampolineHandler() = default; 289 290 void AppleObjCTrampolineHandler::AppleObjCVTables::VTableRegion::SetUpRegion() { 291 // The header looks like: 292 // 293 // uint16_t headerSize 294 // uint16_t descSize 295 // uint32_t descCount 296 // void * next 297 // 298 // First read in the header: 299 300 char memory_buffer[16]; 301 ProcessSP process_sp = m_owner->GetProcessSP(); 302 if (!process_sp) 303 return; 304 DataExtractor data(memory_buffer, sizeof(memory_buffer), 305 process_sp->GetByteOrder(), 306 process_sp->GetAddressByteSize()); 307 size_t actual_size = 8 + process_sp->GetAddressByteSize(); 308 Status error; 309 size_t bytes_read = 310 process_sp->ReadMemory(m_header_addr, memory_buffer, actual_size, error); 311 if (bytes_read != actual_size) { 312 m_valid = false; 313 return; 314 } 315 316 lldb::offset_t offset = 0; 317 const uint16_t header_size = data.GetU16(&offset); 318 const uint16_t descriptor_size = data.GetU16(&offset); 319 const size_t num_descriptors = data.GetU32(&offset); 320 321 m_next_region = data.GetAddress(&offset); 322 323 // If the header size is 0, that means we've come in too early before this 324 // data is set up. 325 // Set ourselves as not valid, and continue. 326 if (header_size == 0 || num_descriptors == 0) { 327 m_valid = false; 328 return; 329 } 330 331 // Now read in all the descriptors: 332 // The descriptor looks like: 333 // 334 // uint32_t offset 335 // uint32_t flags 336 // 337 // Where offset is either 0 - in which case it is unused, or it is 338 // the offset of the vtable code from the beginning of the 339 // descriptor record. Below, we'll convert that into an absolute 340 // code address, since I don't want to have to compute it over and 341 // over. 342 343 // Ingest the whole descriptor array: 344 const lldb::addr_t desc_ptr = m_header_addr + header_size; 345 const size_t desc_array_size = num_descriptors * descriptor_size; 346 DataBufferSP data_sp(new DataBufferHeap(desc_array_size, '\0')); 347 uint8_t *dst = (uint8_t *)data_sp->GetBytes(); 348 349 DataExtractor desc_extractor(dst, desc_array_size, process_sp->GetByteOrder(), 350 process_sp->GetAddressByteSize()); 351 bytes_read = process_sp->ReadMemory(desc_ptr, dst, desc_array_size, error); 352 if (bytes_read != desc_array_size) { 353 m_valid = false; 354 return; 355 } 356 357 // The actual code for the vtables will be laid out consecutively, so I also 358 // compute the start and end of the whole code block. 359 360 offset = 0; 361 m_code_start_addr = 0; 362 m_code_end_addr = 0; 363 364 for (size_t i = 0; i < num_descriptors; i++) { 365 lldb::addr_t start_offset = offset; 366 uint32_t voffset = desc_extractor.GetU32(&offset); 367 uint32_t flags = desc_extractor.GetU32(&offset); 368 lldb::addr_t code_addr = desc_ptr + start_offset + voffset; 369 m_descriptors.push_back(VTableDescriptor(flags, code_addr)); 370 371 if (m_code_start_addr == 0 || code_addr < m_code_start_addr) 372 m_code_start_addr = code_addr; 373 if (code_addr > m_code_end_addr) 374 m_code_end_addr = code_addr; 375 376 offset = start_offset + descriptor_size; 377 } 378 // Finally, a little bird told me that all the vtable code blocks 379 // are the same size. Let's compute the blocks and if they are all 380 // the same add the size to the code end address: 381 lldb::addr_t code_size = 0; 382 bool all_the_same = true; 383 for (size_t i = 0; i < num_descriptors - 1; i++) { 384 lldb::addr_t this_size = 385 m_descriptors[i + 1].code_start - m_descriptors[i].code_start; 386 if (code_size == 0) 387 code_size = this_size; 388 else { 389 if (this_size != code_size) 390 all_the_same = false; 391 if (this_size > code_size) 392 code_size = this_size; 393 } 394 } 395 if (all_the_same) 396 m_code_end_addr += code_size; 397 } 398 399 bool AppleObjCTrampolineHandler::AppleObjCVTables::VTableRegion:: 400 AddressInRegion(lldb::addr_t addr, uint32_t &flags) { 401 if (!IsValid()) 402 return false; 403 404 if (addr < m_code_start_addr || addr > m_code_end_addr) 405 return false; 406 407 std::vector<VTableDescriptor>::iterator pos, end = m_descriptors.end(); 408 for (pos = m_descriptors.begin(); pos != end; pos++) { 409 if (addr <= (*pos).code_start) { 410 flags = (*pos).flags; 411 return true; 412 } 413 } 414 return false; 415 } 416 417 void AppleObjCTrampolineHandler::AppleObjCVTables::VTableRegion::Dump( 418 Stream &s) { 419 s.Printf("Header addr: 0x%" PRIx64 " Code start: 0x%" PRIx64 420 " Code End: 0x%" PRIx64 " Next: 0x%" PRIx64 "\n", 421 m_header_addr, m_code_start_addr, m_code_end_addr, m_next_region); 422 size_t num_elements = m_descriptors.size(); 423 for (size_t i = 0; i < num_elements; i++) { 424 s.Indent(); 425 s.Printf("Code start: 0x%" PRIx64 " Flags: %d\n", 426 m_descriptors[i].code_start, m_descriptors[i].flags); 427 } 428 } 429 430 AppleObjCTrampolineHandler::AppleObjCVTables::AppleObjCVTables( 431 const ProcessSP &process_sp, const ModuleSP &objc_module_sp) 432 : m_process_wp(), m_trampoline_header(LLDB_INVALID_ADDRESS), 433 m_trampolines_changed_bp_id(LLDB_INVALID_BREAK_ID), 434 m_objc_module_sp(objc_module_sp) { 435 if (process_sp) 436 m_process_wp = process_sp; 437 } 438 439 AppleObjCTrampolineHandler::AppleObjCVTables::~AppleObjCVTables() { 440 ProcessSP process_sp = GetProcessSP(); 441 if (process_sp) { 442 if (m_trampolines_changed_bp_id != LLDB_INVALID_BREAK_ID) 443 process_sp->GetTarget().RemoveBreakpointByID(m_trampolines_changed_bp_id); 444 } 445 } 446 447 bool AppleObjCTrampolineHandler::AppleObjCVTables::InitializeVTableSymbols() { 448 if (m_trampoline_header != LLDB_INVALID_ADDRESS) 449 return true; 450 451 ProcessSP process_sp = GetProcessSP(); 452 if (process_sp) { 453 Target &target = process_sp->GetTarget(); 454 455 if (!m_objc_module_sp) { 456 for (ModuleSP module_sp : target.GetImages().Modules()) { 457 if (ObjCLanguageRuntime::Get(*process_sp) 458 ->IsModuleObjCLibrary(module_sp)) { 459 m_objc_module_sp = module_sp; 460 break; 461 } 462 } 463 } 464 465 if (m_objc_module_sp) { 466 ConstString trampoline_name("gdb_objc_trampolines"); 467 const Symbol *trampoline_symbol = 468 m_objc_module_sp->FindFirstSymbolWithNameAndType(trampoline_name, 469 eSymbolTypeData); 470 if (trampoline_symbol != nullptr) { 471 m_trampoline_header = trampoline_symbol->GetLoadAddress(&target); 472 if (m_trampoline_header == LLDB_INVALID_ADDRESS) 473 return false; 474 475 // Next look up the "changed" symbol and set a breakpoint on that... 476 ConstString changed_name("gdb_objc_trampolines_changed"); 477 const Symbol *changed_symbol = 478 m_objc_module_sp->FindFirstSymbolWithNameAndType(changed_name, 479 eSymbolTypeCode); 480 if (changed_symbol != nullptr) { 481 const Address changed_symbol_addr = changed_symbol->GetAddress(); 482 if (!changed_symbol_addr.IsValid()) 483 return false; 484 485 lldb::addr_t changed_addr = 486 changed_symbol_addr.GetOpcodeLoadAddress(&target); 487 if (changed_addr != LLDB_INVALID_ADDRESS) { 488 BreakpointSP trampolines_changed_bp_sp = 489 target.CreateBreakpoint(changed_addr, true, false); 490 if (trampolines_changed_bp_sp) { 491 m_trampolines_changed_bp_id = trampolines_changed_bp_sp->GetID(); 492 trampolines_changed_bp_sp->SetCallback(RefreshTrampolines, this, 493 true); 494 trampolines_changed_bp_sp->SetBreakpointKind( 495 "objc-trampolines-changed"); 496 return true; 497 } 498 } 499 } 500 } 501 } 502 } 503 return false; 504 } 505 506 bool AppleObjCTrampolineHandler::AppleObjCVTables::RefreshTrampolines( 507 void *baton, StoppointCallbackContext *context, lldb::user_id_t break_id, 508 lldb::user_id_t break_loc_id) { 509 AppleObjCVTables *vtable_handler = (AppleObjCVTables *)baton; 510 if (vtable_handler->InitializeVTableSymbols()) { 511 // The Update function is called with the address of an added region. So we 512 // grab that address, and 513 // feed it into ReadRegions. Of course, our friend the ABI will get the 514 // values for us. 515 ExecutionContext exe_ctx(context->exe_ctx_ref); 516 Process *process = exe_ctx.GetProcessPtr(); 517 const ABI *abi = process->GetABI().get(); 518 519 TypeSystemClang *clang_ast_context = 520 ScratchTypeSystemClang::GetForTarget(process->GetTarget()); 521 if (!clang_ast_context) 522 return false; 523 524 ValueList argument_values; 525 Value input_value; 526 CompilerType clang_void_ptr_type = 527 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 528 529 input_value.SetValueType(Value::ValueType::Scalar); 530 // input_value.SetContext (Value::eContextTypeClangType, 531 // clang_void_ptr_type); 532 input_value.SetCompilerType(clang_void_ptr_type); 533 argument_values.PushValue(input_value); 534 535 bool success = 536 abi->GetArgumentValues(exe_ctx.GetThreadRef(), argument_values); 537 if (!success) 538 return false; 539 540 // Now get a pointer value from the zeroth argument. 541 Status error; 542 DataExtractor data; 543 error = argument_values.GetValueAtIndex(0)->GetValueAsData(&exe_ctx, data, 544 nullptr); 545 lldb::offset_t offset = 0; 546 lldb::addr_t region_addr = data.GetAddress(&offset); 547 548 if (region_addr != 0) 549 vtable_handler->ReadRegions(region_addr); 550 } 551 return false; 552 } 553 554 bool AppleObjCTrampolineHandler::AppleObjCVTables::ReadRegions() { 555 // The no argument version reads the start region from the value of 556 // the gdb_regions_header, and gets started from there. 557 558 m_regions.clear(); 559 if (!InitializeVTableSymbols()) 560 return false; 561 Status error; 562 ProcessSP process_sp = GetProcessSP(); 563 if (process_sp) { 564 lldb::addr_t region_addr = 565 process_sp->ReadPointerFromMemory(m_trampoline_header, error); 566 if (error.Success()) 567 return ReadRegions(region_addr); 568 } 569 return false; 570 } 571 572 bool AppleObjCTrampolineHandler::AppleObjCVTables::ReadRegions( 573 lldb::addr_t region_addr) { 574 ProcessSP process_sp = GetProcessSP(); 575 if (!process_sp) 576 return false; 577 578 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP)); 579 580 // We aren't starting at the trampoline symbol. 581 InitializeVTableSymbols(); 582 lldb::addr_t next_region = region_addr; 583 584 // Read in the sizes of the headers. 585 while (next_region != 0) { 586 m_regions.push_back(VTableRegion(this, next_region)); 587 if (!m_regions.back().IsValid()) { 588 m_regions.clear(); 589 return false; 590 } 591 if (log) { 592 StreamString s; 593 m_regions.back().Dump(s); 594 LLDB_LOGF(log, "Read vtable region: \n%s", s.GetData()); 595 } 596 597 next_region = m_regions.back().GetNextRegionAddr(); 598 } 599 600 return true; 601 } 602 603 bool AppleObjCTrampolineHandler::AppleObjCVTables::IsAddressInVTables( 604 lldb::addr_t addr, uint32_t &flags) { 605 region_collection::iterator pos, end = m_regions.end(); 606 for (pos = m_regions.begin(); pos != end; pos++) { 607 if ((*pos).AddressInRegion(addr, flags)) 608 return true; 609 } 610 return false; 611 } 612 613 const AppleObjCTrampolineHandler::DispatchFunction 614 AppleObjCTrampolineHandler::g_dispatch_functions[] = { 615 // NAME STRET SUPER SUPER2 FIXUP TYPE 616 {"objc_msgSend", false, false, false, DispatchFunction::eFixUpNone}, 617 {"objc_msgSend_fixup", false, false, false, 618 DispatchFunction::eFixUpToFix}, 619 {"objc_msgSend_fixedup", false, false, false, 620 DispatchFunction::eFixUpFixed}, 621 {"objc_msgSend_stret", true, false, false, 622 DispatchFunction::eFixUpNone}, 623 {"objc_msgSend_stret_fixup", true, false, false, 624 DispatchFunction::eFixUpToFix}, 625 {"objc_msgSend_stret_fixedup", true, false, false, 626 DispatchFunction::eFixUpFixed}, 627 {"objc_msgSend_fpret", false, false, false, 628 DispatchFunction::eFixUpNone}, 629 {"objc_msgSend_fpret_fixup", false, false, false, 630 DispatchFunction::eFixUpToFix}, 631 {"objc_msgSend_fpret_fixedup", false, false, false, 632 DispatchFunction::eFixUpFixed}, 633 {"objc_msgSend_fp2ret", false, false, true, 634 DispatchFunction::eFixUpNone}, 635 {"objc_msgSend_fp2ret_fixup", false, false, true, 636 DispatchFunction::eFixUpToFix}, 637 {"objc_msgSend_fp2ret_fixedup", false, false, true, 638 DispatchFunction::eFixUpFixed}, 639 {"objc_msgSendSuper", false, true, false, DispatchFunction::eFixUpNone}, 640 {"objc_msgSendSuper_stret", true, true, false, 641 DispatchFunction::eFixUpNone}, 642 {"objc_msgSendSuper2", false, true, true, DispatchFunction::eFixUpNone}, 643 {"objc_msgSendSuper2_fixup", false, true, true, 644 DispatchFunction::eFixUpToFix}, 645 {"objc_msgSendSuper2_fixedup", false, true, true, 646 DispatchFunction::eFixUpFixed}, 647 {"objc_msgSendSuper2_stret", true, true, true, 648 DispatchFunction::eFixUpNone}, 649 {"objc_msgSendSuper2_stret_fixup", true, true, true, 650 DispatchFunction::eFixUpToFix}, 651 {"objc_msgSendSuper2_stret_fixedup", true, true, true, 652 DispatchFunction::eFixUpFixed}, 653 }; 654 655 // This is the table of ObjC "accelerated dispatch" functions. They are a set 656 // of objc methods that are "seldom overridden" and so the compiler replaces the 657 // objc_msgSend with a call to one of the dispatch functions. That will check 658 // whether the method has been overridden, and directly call the Foundation 659 // implementation if not. 660 // This table is supposed to be complete. If ones get added in the future, we 661 // will have to add them to the table. 662 const char *AppleObjCTrampolineHandler::g_opt_dispatch_names[] = { 663 "objc_alloc", 664 "objc_autorelease", 665 "objc_release", 666 "objc_retain", 667 "objc_alloc_init", 668 "objc_allocWithZone", 669 "objc_opt_class", 670 "objc_opt_isKindOfClass", 671 "objc_opt_new", 672 "objc_opt_respondsToSelector", 673 "objc_opt_self", 674 }; 675 676 AppleObjCTrampolineHandler::AppleObjCTrampolineHandler( 677 const ProcessSP &process_sp, const ModuleSP &objc_module_sp) 678 : m_process_wp(), m_objc_module_sp(objc_module_sp), 679 m_lookup_implementation_function_code(nullptr), 680 m_impl_fn_addr(LLDB_INVALID_ADDRESS), 681 m_impl_stret_fn_addr(LLDB_INVALID_ADDRESS), 682 m_msg_forward_addr(LLDB_INVALID_ADDRESS) { 683 if (process_sp) 684 m_process_wp = process_sp; 685 // Look up the known resolution functions: 686 687 ConstString get_impl_name("class_getMethodImplementation"); 688 ConstString get_impl_stret_name("class_getMethodImplementation_stret"); 689 ConstString msg_forward_name("_objc_msgForward"); 690 ConstString msg_forward_stret_name("_objc_msgForward_stret"); 691 692 Target *target = process_sp ? &process_sp->GetTarget() : nullptr; 693 const Symbol *class_getMethodImplementation = 694 m_objc_module_sp->FindFirstSymbolWithNameAndType(get_impl_name, 695 eSymbolTypeCode); 696 const Symbol *class_getMethodImplementation_stret = 697 m_objc_module_sp->FindFirstSymbolWithNameAndType(get_impl_stret_name, 698 eSymbolTypeCode); 699 const Symbol *msg_forward = m_objc_module_sp->FindFirstSymbolWithNameAndType( 700 msg_forward_name, eSymbolTypeCode); 701 const Symbol *msg_forward_stret = 702 m_objc_module_sp->FindFirstSymbolWithNameAndType(msg_forward_stret_name, 703 eSymbolTypeCode); 704 705 if (class_getMethodImplementation) 706 m_impl_fn_addr = 707 class_getMethodImplementation->GetAddress().GetOpcodeLoadAddress( 708 target); 709 if (class_getMethodImplementation_stret) 710 m_impl_stret_fn_addr = 711 class_getMethodImplementation_stret->GetAddress().GetOpcodeLoadAddress( 712 target); 713 if (msg_forward) 714 m_msg_forward_addr = msg_forward->GetAddress().GetOpcodeLoadAddress(target); 715 if (msg_forward_stret) 716 m_msg_forward_stret_addr = 717 msg_forward_stret->GetAddress().GetOpcodeLoadAddress(target); 718 719 // FIXME: Do some kind of logging here. 720 if (m_impl_fn_addr == LLDB_INVALID_ADDRESS) { 721 // If we can't even find the ordinary get method implementation function, 722 // then we aren't going to be able to 723 // step through any method dispatches. Warn to that effect and get out of 724 // here. 725 if (process_sp->CanJIT()) { 726 process_sp->GetTarget().GetDebugger().GetErrorStream().Printf( 727 "Could not find implementation lookup function \"%s\"" 728 " step in through ObjC method dispatch will not work.\n", 729 get_impl_name.AsCString()); 730 } 731 return; 732 } else if (m_impl_stret_fn_addr == LLDB_INVALID_ADDRESS) { 733 // It there is no stret return lookup function, assume that it is the same 734 // as the straight lookup: 735 m_impl_stret_fn_addr = m_impl_fn_addr; 736 // Also we will use the version of the lookup code that doesn't rely on the 737 // stret version of the function. 738 m_lookup_implementation_function_code = 739 g_lookup_implementation_no_stret_function_code; 740 } else { 741 m_lookup_implementation_function_code = 742 g_lookup_implementation_with_stret_function_code; 743 } 744 745 // Look up the addresses for the objc dispatch functions and cache 746 // them. For now I'm inspecting the symbol names dynamically to 747 // figure out how to dispatch to them. If it becomes more 748 // complicated than this we can turn the g_dispatch_functions char * 749 // array into a template table, and populate the DispatchFunction 750 // map from there. 751 752 for (size_t i = 0; i != llvm::array_lengthof(g_dispatch_functions); i++) { 753 ConstString name_const_str(g_dispatch_functions[i].name); 754 const Symbol *msgSend_symbol = 755 m_objc_module_sp->FindFirstSymbolWithNameAndType(name_const_str, 756 eSymbolTypeCode); 757 if (msgSend_symbol && msgSend_symbol->ValueIsAddress()) { 758 // FIXME: Make g_dispatch_functions static table of 759 // DispatchFunctions, and have the map be address->index. 760 // Problem is we also need to lookup the dispatch function. For 761 // now we could have a side table of stret & non-stret dispatch 762 // functions. If that's as complex as it gets, we're fine. 763 764 lldb::addr_t sym_addr = 765 msgSend_symbol->GetAddressRef().GetOpcodeLoadAddress(target); 766 767 m_msgSend_map.insert(std::pair<lldb::addr_t, int>(sym_addr, i)); 768 } 769 } 770 771 // Similarly, cache the addresses of the "optimized dispatch" function. 772 for (size_t i = 0; i != llvm::array_lengthof(g_opt_dispatch_names); i++) { 773 ConstString name_const_str(g_opt_dispatch_names[i]); 774 const Symbol *msgSend_symbol = 775 m_objc_module_sp->FindFirstSymbolWithNameAndType(name_const_str, 776 eSymbolTypeCode); 777 if (msgSend_symbol && msgSend_symbol->ValueIsAddress()) { 778 lldb::addr_t sym_addr = 779 msgSend_symbol->GetAddressRef().GetOpcodeLoadAddress(target); 780 781 m_opt_dispatch_map.emplace(sym_addr, i); 782 } 783 } 784 785 // Build our vtable dispatch handler here: 786 m_vtables_up = 787 std::make_unique<AppleObjCVTables>(process_sp, m_objc_module_sp); 788 if (m_vtables_up) 789 m_vtables_up->ReadRegions(); 790 } 791 792 lldb::addr_t 793 AppleObjCTrampolineHandler::SetupDispatchFunction(Thread &thread, 794 ValueList &dispatch_values) { 795 ThreadSP thread_sp(thread.shared_from_this()); 796 ExecutionContext exe_ctx(thread_sp); 797 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP)); 798 799 lldb::addr_t args_addr = LLDB_INVALID_ADDRESS; 800 FunctionCaller *impl_function_caller = nullptr; 801 802 // Scope for mutex locker: 803 { 804 std::lock_guard<std::mutex> guard(m_impl_function_mutex); 805 806 // First stage is to make the ClangUtility to hold our injected function: 807 808 if (!m_impl_code) { 809 if (m_lookup_implementation_function_code != nullptr) { 810 auto utility_fn_or_error = exe_ctx.GetTargetRef().CreateUtilityFunction( 811 m_lookup_implementation_function_code, 812 g_lookup_implementation_function_name, eLanguageTypeC, exe_ctx); 813 if (!utility_fn_or_error) { 814 LLDB_LOG_ERROR( 815 log, utility_fn_or_error.takeError(), 816 "Failed to get Utility Function for implementation lookup: {0}."); 817 return args_addr; 818 } 819 m_impl_code = std::move(*utility_fn_or_error); 820 } else { 821 LLDB_LOGF(log, "No method lookup implementation code."); 822 return LLDB_INVALID_ADDRESS; 823 } 824 825 // Next make the runner function for our implementation utility function. 826 TypeSystemClang *clang_ast_context = ScratchTypeSystemClang::GetForTarget( 827 thread.GetProcess()->GetTarget()); 828 if (!clang_ast_context) 829 return LLDB_INVALID_ADDRESS; 830 831 CompilerType clang_void_ptr_type = 832 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 833 Status error; 834 835 impl_function_caller = m_impl_code->MakeFunctionCaller( 836 clang_void_ptr_type, dispatch_values, thread_sp, error); 837 if (error.Fail()) { 838 LLDB_LOGF(log, 839 "Error getting function caller for dispatch lookup: \"%s\".", 840 error.AsCString()); 841 return args_addr; 842 } 843 } else { 844 impl_function_caller = m_impl_code->GetFunctionCaller(); 845 } 846 } 847 848 // Now write down the argument values for this particular call. 849 // This looks like it might be a race condition if other threads 850 // were calling into here, but actually it isn't because we allocate 851 // a new args structure for this call by passing args_addr = 852 // LLDB_INVALID_ADDRESS... 853 854 DiagnosticManager diagnostics; 855 if (!impl_function_caller->WriteFunctionArguments( 856 exe_ctx, args_addr, dispatch_values, diagnostics)) { 857 if (log) { 858 LLDB_LOGF(log, "Error writing function arguments."); 859 diagnostics.Dump(log); 860 } 861 return args_addr; 862 } 863 864 return args_addr; 865 } 866 867 const AppleObjCTrampolineHandler::DispatchFunction * 868 AppleObjCTrampolineHandler::FindDispatchFunction(lldb::addr_t addr) { 869 MsgsendMap::iterator pos; 870 pos = m_msgSend_map.find(addr); 871 if (pos != m_msgSend_map.end()) { 872 return &g_dispatch_functions[(*pos).second]; 873 } 874 return nullptr; 875 } 876 877 void 878 AppleObjCTrampolineHandler::ForEachDispatchFunction( 879 std::function<void(lldb::addr_t, 880 const DispatchFunction &)> callback) { 881 for (auto elem : m_msgSend_map) { 882 callback(elem.first, g_dispatch_functions[elem.second]); 883 } 884 } 885 886 ThreadPlanSP 887 AppleObjCTrampolineHandler::GetStepThroughDispatchPlan(Thread &thread, 888 bool stop_others) { 889 ThreadPlanSP ret_plan_sp; 890 lldb::addr_t curr_pc = thread.GetRegisterContext()->GetPC(); 891 892 DispatchFunction vtable_dispatch = {"vtable", false, false, false, 893 DispatchFunction::eFixUpFixed}; 894 895 // First step is to look and see if we are in one of the known ObjC 896 // dispatch functions. We've already compiled a table of same, so 897 // consult it. 898 899 const DispatchFunction *this_dispatch = FindDispatchFunction(curr_pc); 900 901 // Next check to see if we are in a vtable region: 902 903 if (!this_dispatch && m_vtables_up) { 904 uint32_t flags; 905 if (m_vtables_up->IsAddressInVTables(curr_pc, flags)) { 906 vtable_dispatch.stret_return = 907 (flags & AppleObjCVTables::eOBJC_TRAMPOLINE_STRET) == 908 AppleObjCVTables::eOBJC_TRAMPOLINE_STRET; 909 this_dispatch = &vtable_dispatch; 910 } 911 } 912 913 if (this_dispatch) { 914 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP)); 915 916 // We are decoding a method dispatch. First job is to pull the 917 // arguments out: 918 919 lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0); 920 921 const ABI *abi = nullptr; 922 ProcessSP process_sp(thread.CalculateProcess()); 923 if (process_sp) 924 abi = process_sp->GetABI().get(); 925 if (abi == nullptr) 926 return ret_plan_sp; 927 928 TargetSP target_sp(thread.CalculateTarget()); 929 930 TypeSystemClang *clang_ast_context = 931 ScratchTypeSystemClang::GetForTarget(*target_sp); 932 if (!clang_ast_context) 933 return ret_plan_sp; 934 935 ValueList argument_values; 936 Value void_ptr_value; 937 CompilerType clang_void_ptr_type = 938 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 939 void_ptr_value.SetValueType(Value::ValueType::Scalar); 940 // void_ptr_value.SetContext (Value::eContextTypeClangType, 941 // clang_void_ptr_type); 942 void_ptr_value.SetCompilerType(clang_void_ptr_type); 943 944 int obj_index; 945 int sel_index; 946 947 // If this is a struct return dispatch, then the first argument is 948 // the return struct pointer, and the object is the second, and 949 // the selector is the third. Otherwise the object is the first 950 // and the selector the second. 951 if (this_dispatch->stret_return) { 952 obj_index = 1; 953 sel_index = 2; 954 argument_values.PushValue(void_ptr_value); 955 argument_values.PushValue(void_ptr_value); 956 argument_values.PushValue(void_ptr_value); 957 } else { 958 obj_index = 0; 959 sel_index = 1; 960 argument_values.PushValue(void_ptr_value); 961 argument_values.PushValue(void_ptr_value); 962 } 963 964 bool success = abi->GetArgumentValues(thread, argument_values); 965 if (!success) 966 return ret_plan_sp; 967 968 lldb::addr_t obj_addr = 969 argument_values.GetValueAtIndex(obj_index)->GetScalar().ULongLong(); 970 if (obj_addr == 0x0) { 971 LLDB_LOGF( 972 log, 973 "Asked to step to dispatch to nil object, returning empty plan."); 974 return ret_plan_sp; 975 } 976 977 ExecutionContext exe_ctx(thread.shared_from_this()); 978 Process *process = exe_ctx.GetProcessPtr(); 979 // isa_addr will store the class pointer that the method is being 980 // dispatched to - so either the class directly or the super class 981 // if this is one of the objc_msgSendSuper flavors. That's mostly 982 // used to look up the class/selector pair in our cache. 983 984 lldb::addr_t isa_addr = LLDB_INVALID_ADDRESS; 985 lldb::addr_t sel_addr = 986 argument_values.GetValueAtIndex(sel_index)->GetScalar().ULongLong(); 987 988 // Figure out the class this is being dispatched to and see if 989 // we've already cached this method call, If so we can push a 990 // run-to-address plan directly. Otherwise we have to figure out 991 // where the implementation lives. 992 993 if (this_dispatch->is_super) { 994 if (this_dispatch->is_super2) { 995 // In the objc_msgSendSuper2 case, we don't get the object 996 // directly, we get a structure containing the object and the 997 // class to which the super message is being sent. So we need 998 // to dig the super out of the class and use that. 999 1000 Value super_value(*(argument_values.GetValueAtIndex(obj_index))); 1001 super_value.GetScalar() += process->GetAddressByteSize(); 1002 super_value.ResolveValue(&exe_ctx); 1003 1004 if (super_value.GetScalar().IsValid()) { 1005 1006 // isa_value now holds the class pointer. The second word of the 1007 // class pointer is the super-class pointer: 1008 super_value.GetScalar() += process->GetAddressByteSize(); 1009 super_value.ResolveValue(&exe_ctx); 1010 if (super_value.GetScalar().IsValid()) 1011 isa_addr = super_value.GetScalar().ULongLong(); 1012 else { 1013 LLDB_LOGF(log, "Failed to extract the super class value from the " 1014 "class in objc_super."); 1015 } 1016 } else { 1017 LLDB_LOGF(log, "Failed to extract the class value from objc_super."); 1018 } 1019 } else { 1020 // In the objc_msgSendSuper case, we don't get the object 1021 // directly, we get a two element structure containing the 1022 // object and the super class to which the super message is 1023 // being sent. So the class we want is the second element of 1024 // this structure. 1025 1026 Value super_value(*(argument_values.GetValueAtIndex(obj_index))); 1027 super_value.GetScalar() += process->GetAddressByteSize(); 1028 super_value.ResolveValue(&exe_ctx); 1029 1030 if (super_value.GetScalar().IsValid()) { 1031 isa_addr = super_value.GetScalar().ULongLong(); 1032 } else { 1033 LLDB_LOGF(log, "Failed to extract the class value from objc_super."); 1034 } 1035 } 1036 } else { 1037 // In the direct dispatch case, the object->isa is the class pointer we 1038 // want. 1039 1040 // This is a little cheesy, but since object->isa is the first field, 1041 // making the object value a load address value and resolving it will get 1042 // the pointer sized data pointed to by that value... 1043 1044 // Note, it isn't a fatal error not to be able to get the 1045 // address from the object, since this might be a "tagged 1046 // pointer" which isn't a real object, but rather some word 1047 // length encoded dingus. 1048 1049 Value isa_value(*(argument_values.GetValueAtIndex(obj_index))); 1050 1051 isa_value.SetValueType(Value::ValueType::LoadAddress); 1052 isa_value.ResolveValue(&exe_ctx); 1053 if (isa_value.GetScalar().IsValid()) { 1054 isa_addr = isa_value.GetScalar().ULongLong(); 1055 } else { 1056 LLDB_LOGF(log, "Failed to extract the isa value from object."); 1057 } 1058 } 1059 1060 // Okay, we've got the address of the class for which we're resolving this, 1061 // let's see if it's in our cache: 1062 lldb::addr_t impl_addr = LLDB_INVALID_ADDRESS; 1063 1064 if (isa_addr != LLDB_INVALID_ADDRESS) { 1065 if (log) { 1066 LLDB_LOGF(log, 1067 "Resolving call for class - 0x%" PRIx64 1068 " and selector - 0x%" PRIx64, 1069 isa_addr, sel_addr); 1070 } 1071 ObjCLanguageRuntime *objc_runtime = 1072 ObjCLanguageRuntime::Get(*thread.GetProcess()); 1073 assert(objc_runtime != nullptr); 1074 1075 impl_addr = objc_runtime->LookupInMethodCache(isa_addr, sel_addr); 1076 } 1077 1078 if (impl_addr != LLDB_INVALID_ADDRESS) { 1079 // Yup, it was in the cache, so we can run to that address directly. 1080 1081 LLDB_LOGF(log, "Found implementation address in cache: 0x%" PRIx64, 1082 impl_addr); 1083 1084 ret_plan_sp = std::make_shared<ThreadPlanRunToAddress>(thread, impl_addr, 1085 stop_others); 1086 } else { 1087 // We haven't seen this class/selector pair yet. Look it up. 1088 StreamString errors; 1089 Address impl_code_address; 1090 1091 ValueList dispatch_values; 1092 1093 // We've will inject a little function in the target that takes the 1094 // object, selector and some flags, 1095 // and figures out the implementation. Looks like: 1096 // void *__lldb_objc_find_implementation_for_selector (void *object, 1097 // void *sel, 1098 // int is_stret, 1099 // int is_super, 1100 // int is_super2, 1101 // int is_fixup, 1102 // int is_fixed, 1103 // int debug) 1104 // So set up the arguments for that call. 1105 1106 dispatch_values.PushValue(*(argument_values.GetValueAtIndex(obj_index))); 1107 dispatch_values.PushValue(*(argument_values.GetValueAtIndex(sel_index))); 1108 1109 Value flag_value; 1110 CompilerType clang_int_type = 1111 clang_ast_context->GetBuiltinTypeForEncodingAndBitSize( 1112 lldb::eEncodingSint, 32); 1113 flag_value.SetValueType(Value::ValueType::Scalar); 1114 // flag_value.SetContext (Value::eContextTypeClangType, clang_int_type); 1115 flag_value.SetCompilerType(clang_int_type); 1116 1117 if (this_dispatch->stret_return) 1118 flag_value.GetScalar() = 1; 1119 else 1120 flag_value.GetScalar() = 0; 1121 dispatch_values.PushValue(flag_value); 1122 1123 if (this_dispatch->is_super) 1124 flag_value.GetScalar() = 1; 1125 else 1126 flag_value.GetScalar() = 0; 1127 dispatch_values.PushValue(flag_value); 1128 1129 if (this_dispatch->is_super2) 1130 flag_value.GetScalar() = 1; 1131 else 1132 flag_value.GetScalar() = 0; 1133 dispatch_values.PushValue(flag_value); 1134 1135 switch (this_dispatch->fixedup) { 1136 case DispatchFunction::eFixUpNone: 1137 flag_value.GetScalar() = 0; 1138 dispatch_values.PushValue(flag_value); 1139 dispatch_values.PushValue(flag_value); 1140 break; 1141 case DispatchFunction::eFixUpFixed: 1142 flag_value.GetScalar() = 1; 1143 dispatch_values.PushValue(flag_value); 1144 flag_value.GetScalar() = 1; 1145 dispatch_values.PushValue(flag_value); 1146 break; 1147 case DispatchFunction::eFixUpToFix: 1148 flag_value.GetScalar() = 1; 1149 dispatch_values.PushValue(flag_value); 1150 flag_value.GetScalar() = 0; 1151 dispatch_values.PushValue(flag_value); 1152 break; 1153 } 1154 if (log && log->GetVerbose()) 1155 flag_value.GetScalar() = 1; 1156 else 1157 flag_value.GetScalar() = 0; // FIXME - Set to 0 when debugging is done. 1158 dispatch_values.PushValue(flag_value); 1159 1160 ret_plan_sp = std::make_shared<AppleThreadPlanStepThroughObjCTrampoline>( 1161 thread, *this, dispatch_values, isa_addr, sel_addr); 1162 if (log) { 1163 StreamString s; 1164 ret_plan_sp->GetDescription(&s, eDescriptionLevelFull); 1165 LLDB_LOGF(log, "Using ObjC step plan: %s.\n", s.GetData()); 1166 } 1167 } 1168 } 1169 1170 // Finally, check if we have hit an "optimized dispatch" function. This will 1171 // either directly call the base implementation or dispatch an objc_msgSend 1172 // if the method has been overridden. So we just do a "step in/step out", 1173 // setting a breakpoint on objc_msgSend, and if we hit the msgSend, we 1174 // will automatically step in again. That's the job of the 1175 // AppleThreadPlanStepThroughDirectDispatch. 1176 if (!this_dispatch && !ret_plan_sp) { 1177 MsgsendMap::iterator pos; 1178 pos = m_opt_dispatch_map.find(curr_pc); 1179 if (pos != m_opt_dispatch_map.end()) { 1180 const char *opt_name = g_opt_dispatch_names[(*pos).second]; 1181 ret_plan_sp = std::make_shared<AppleThreadPlanStepThroughDirectDispatch>( 1182 thread, *this, opt_name); 1183 } 1184 } 1185 1186 return ret_plan_sp; 1187 } 1188 1189 FunctionCaller * 1190 AppleObjCTrampolineHandler::GetLookupImplementationFunctionCaller() { 1191 return m_impl_code->GetFunctionCaller(); 1192 } 1193