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
VTableRegion(AppleObjCVTables * owner,lldb::addr_t header_addr)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
~AppleObjCTrampolineHandler()288 AppleObjCTrampolineHandler::~AppleObjCTrampolineHandler() {}
289
SetUpRegion()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::
AddressInRegion(lldb::addr_t addr,uint32_t & flags)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
Dump(Stream & s)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
AppleObjCVTables(const ProcessSP & process_sp,const ModuleSP & objc_module_sp)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
~AppleObjCVTables()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
InitializeVTableSymbols()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 const ModuleList &target_modules = target.GetImages();
456 std::lock_guard<std::recursive_mutex> guard(target_modules.GetMutex());
457 size_t num_modules = target_modules.GetSize();
458 if (!m_objc_module_sp) {
459 for (size_t i = 0; i < num_modules; i++) {
460 if (ObjCLanguageRuntime::Get(*process_sp)
461 ->IsModuleObjCLibrary(
462 target_modules.GetModuleAtIndexUnlocked(i))) {
463 m_objc_module_sp = target_modules.GetModuleAtIndexUnlocked(i);
464 break;
465 }
466 }
467 }
468
469 if (m_objc_module_sp) {
470 ConstString trampoline_name("gdb_objc_trampolines");
471 const Symbol *trampoline_symbol =
472 m_objc_module_sp->FindFirstSymbolWithNameAndType(trampoline_name,
473 eSymbolTypeData);
474 if (trampoline_symbol != nullptr) {
475 m_trampoline_header = trampoline_symbol->GetLoadAddress(&target);
476 if (m_trampoline_header == LLDB_INVALID_ADDRESS)
477 return false;
478
479 // Next look up the "changed" symbol and set a breakpoint on that...
480 ConstString changed_name("gdb_objc_trampolines_changed");
481 const Symbol *changed_symbol =
482 m_objc_module_sp->FindFirstSymbolWithNameAndType(changed_name,
483 eSymbolTypeCode);
484 if (changed_symbol != nullptr) {
485 const Address changed_symbol_addr = changed_symbol->GetAddress();
486 if (!changed_symbol_addr.IsValid())
487 return false;
488
489 lldb::addr_t changed_addr =
490 changed_symbol_addr.GetOpcodeLoadAddress(&target);
491 if (changed_addr != LLDB_INVALID_ADDRESS) {
492 BreakpointSP trampolines_changed_bp_sp =
493 target.CreateBreakpoint(changed_addr, true, false);
494 if (trampolines_changed_bp_sp) {
495 m_trampolines_changed_bp_id = trampolines_changed_bp_sp->GetID();
496 trampolines_changed_bp_sp->SetCallback(RefreshTrampolines, this,
497 true);
498 trampolines_changed_bp_sp->SetBreakpointKind(
499 "objc-trampolines-changed");
500 return true;
501 }
502 }
503 }
504 }
505 }
506 }
507 return false;
508 }
509
RefreshTrampolines(void * baton,StoppointCallbackContext * context,lldb::user_id_t break_id,lldb::user_id_t break_loc_id)510 bool AppleObjCTrampolineHandler::AppleObjCVTables::RefreshTrampolines(
511 void *baton, StoppointCallbackContext *context, lldb::user_id_t break_id,
512 lldb::user_id_t break_loc_id) {
513 AppleObjCVTables *vtable_handler = (AppleObjCVTables *)baton;
514 if (vtable_handler->InitializeVTableSymbols()) {
515 // The Update function is called with the address of an added region. So we
516 // grab that address, and
517 // feed it into ReadRegions. Of course, our friend the ABI will get the
518 // values for us.
519 ExecutionContext exe_ctx(context->exe_ctx_ref);
520 Process *process = exe_ctx.GetProcessPtr();
521 const ABI *abi = process->GetABI().get();
522
523 TypeSystemClang *clang_ast_context =
524 ScratchTypeSystemClang::GetForTarget(process->GetTarget());
525 if (!clang_ast_context)
526 return false;
527
528 ValueList argument_values;
529 Value input_value;
530 CompilerType clang_void_ptr_type =
531 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
532
533 input_value.SetValueType(Value::eValueTypeScalar);
534 // input_value.SetContext (Value::eContextTypeClangType,
535 // clang_void_ptr_type);
536 input_value.SetCompilerType(clang_void_ptr_type);
537 argument_values.PushValue(input_value);
538
539 bool success =
540 abi->GetArgumentValues(exe_ctx.GetThreadRef(), argument_values);
541 if (!success)
542 return false;
543
544 // Now get a pointer value from the zeroth argument.
545 Status error;
546 DataExtractor data;
547 error = argument_values.GetValueAtIndex(0)->GetValueAsData(&exe_ctx, data,
548 nullptr);
549 lldb::offset_t offset = 0;
550 lldb::addr_t region_addr = data.GetAddress(&offset);
551
552 if (region_addr != 0)
553 vtable_handler->ReadRegions(region_addr);
554 }
555 return false;
556 }
557
ReadRegions()558 bool AppleObjCTrampolineHandler::AppleObjCVTables::ReadRegions() {
559 // The no argument version reads the start region from the value of
560 // the gdb_regions_header, and gets started from there.
561
562 m_regions.clear();
563 if (!InitializeVTableSymbols())
564 return false;
565 Status error;
566 ProcessSP process_sp = GetProcessSP();
567 if (process_sp) {
568 lldb::addr_t region_addr =
569 process_sp->ReadPointerFromMemory(m_trampoline_header, error);
570 if (error.Success())
571 return ReadRegions(region_addr);
572 }
573 return false;
574 }
575
ReadRegions(lldb::addr_t region_addr)576 bool AppleObjCTrampolineHandler::AppleObjCVTables::ReadRegions(
577 lldb::addr_t region_addr) {
578 ProcessSP process_sp = GetProcessSP();
579 if (!process_sp)
580 return false;
581
582 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
583
584 // We aren't starting at the trampoline symbol.
585 InitializeVTableSymbols();
586 lldb::addr_t next_region = region_addr;
587
588 // Read in the sizes of the headers.
589 while (next_region != 0) {
590 m_regions.push_back(VTableRegion(this, next_region));
591 if (!m_regions.back().IsValid()) {
592 m_regions.clear();
593 return false;
594 }
595 if (log) {
596 StreamString s;
597 m_regions.back().Dump(s);
598 LLDB_LOGF(log, "Read vtable region: \n%s", s.GetData());
599 }
600
601 next_region = m_regions.back().GetNextRegionAddr();
602 }
603
604 return true;
605 }
606
IsAddressInVTables(lldb::addr_t addr,uint32_t & flags)607 bool AppleObjCTrampolineHandler::AppleObjCVTables::IsAddressInVTables(
608 lldb::addr_t addr, uint32_t &flags) {
609 region_collection::iterator pos, end = m_regions.end();
610 for (pos = m_regions.begin(); pos != end; pos++) {
611 if ((*pos).AddressInRegion(addr, flags))
612 return true;
613 }
614 return false;
615 }
616
617 const AppleObjCTrampolineHandler::DispatchFunction
618 AppleObjCTrampolineHandler::g_dispatch_functions[] = {
619 // NAME STRET SUPER SUPER2 FIXUP TYPE
620 {"objc_msgSend", false, false, false, DispatchFunction::eFixUpNone},
621 {"objc_msgSend_fixup", false, false, false,
622 DispatchFunction::eFixUpToFix},
623 {"objc_msgSend_fixedup", false, false, false,
624 DispatchFunction::eFixUpFixed},
625 {"objc_msgSend_stret", true, false, false,
626 DispatchFunction::eFixUpNone},
627 {"objc_msgSend_stret_fixup", true, false, false,
628 DispatchFunction::eFixUpToFix},
629 {"objc_msgSend_stret_fixedup", true, false, false,
630 DispatchFunction::eFixUpFixed},
631 {"objc_msgSend_fpret", false, false, false,
632 DispatchFunction::eFixUpNone},
633 {"objc_msgSend_fpret_fixup", false, false, false,
634 DispatchFunction::eFixUpToFix},
635 {"objc_msgSend_fpret_fixedup", false, false, false,
636 DispatchFunction::eFixUpFixed},
637 {"objc_msgSend_fp2ret", false, false, true,
638 DispatchFunction::eFixUpNone},
639 {"objc_msgSend_fp2ret_fixup", false, false, true,
640 DispatchFunction::eFixUpToFix},
641 {"objc_msgSend_fp2ret_fixedup", false, false, true,
642 DispatchFunction::eFixUpFixed},
643 {"objc_msgSendSuper", false, true, false, DispatchFunction::eFixUpNone},
644 {"objc_msgSendSuper_stret", true, true, false,
645 DispatchFunction::eFixUpNone},
646 {"objc_msgSendSuper2", false, true, true, DispatchFunction::eFixUpNone},
647 {"objc_msgSendSuper2_fixup", false, true, true,
648 DispatchFunction::eFixUpToFix},
649 {"objc_msgSendSuper2_fixedup", false, true, true,
650 DispatchFunction::eFixUpFixed},
651 {"objc_msgSendSuper2_stret", true, true, true,
652 DispatchFunction::eFixUpNone},
653 {"objc_msgSendSuper2_stret_fixup", true, true, true,
654 DispatchFunction::eFixUpToFix},
655 {"objc_msgSendSuper2_stret_fixedup", true, true, true,
656 DispatchFunction::eFixUpFixed},
657 };
658
659 // This is the table of ObjC "accelerated dispatch" functions. They are a set
660 // of objc methods that are "seldom overridden" and so the compiler replaces the
661 // objc_msgSend with a call to one of the dispatch functions. That will check
662 // whether the method has been overridden, and directly call the Foundation
663 // implementation if not.
664 // This table is supposed to be complete. If ones get added in the future, we
665 // will have to add them to the table.
666 const char *AppleObjCTrampolineHandler::g_opt_dispatch_names[] = {
667 "objc_alloc",
668 "objc_autorelease",
669 "objc_release",
670 "objc_retain",
671 "objc_alloc_init",
672 "objc_allocWithZone",
673 "objc_opt_class",
674 "objc_opt_isKindOfClass",
675 "objc_opt_new",
676 "objc_opt_respondsToSelector",
677 "objc_opt_self",
678 };
679
AppleObjCTrampolineHandler(const ProcessSP & process_sp,const ModuleSP & objc_module_sp)680 AppleObjCTrampolineHandler::AppleObjCTrampolineHandler(
681 const ProcessSP &process_sp, const ModuleSP &objc_module_sp)
682 : m_process_wp(), m_objc_module_sp(objc_module_sp),
683 m_lookup_implementation_function_code(nullptr),
684 m_impl_fn_addr(LLDB_INVALID_ADDRESS),
685 m_impl_stret_fn_addr(LLDB_INVALID_ADDRESS),
686 m_msg_forward_addr(LLDB_INVALID_ADDRESS) {
687 if (process_sp)
688 m_process_wp = process_sp;
689 // Look up the known resolution functions:
690
691 ConstString get_impl_name("class_getMethodImplementation");
692 ConstString get_impl_stret_name("class_getMethodImplementation_stret");
693 ConstString msg_forward_name("_objc_msgForward");
694 ConstString msg_forward_stret_name("_objc_msgForward_stret");
695
696 Target *target = process_sp ? &process_sp->GetTarget() : nullptr;
697 const Symbol *class_getMethodImplementation =
698 m_objc_module_sp->FindFirstSymbolWithNameAndType(get_impl_name,
699 eSymbolTypeCode);
700 const Symbol *class_getMethodImplementation_stret =
701 m_objc_module_sp->FindFirstSymbolWithNameAndType(get_impl_stret_name,
702 eSymbolTypeCode);
703 const Symbol *msg_forward = m_objc_module_sp->FindFirstSymbolWithNameAndType(
704 msg_forward_name, eSymbolTypeCode);
705 const Symbol *msg_forward_stret =
706 m_objc_module_sp->FindFirstSymbolWithNameAndType(msg_forward_stret_name,
707 eSymbolTypeCode);
708
709 if (class_getMethodImplementation)
710 m_impl_fn_addr =
711 class_getMethodImplementation->GetAddress().GetOpcodeLoadAddress(
712 target);
713 if (class_getMethodImplementation_stret)
714 m_impl_stret_fn_addr =
715 class_getMethodImplementation_stret->GetAddress().GetOpcodeLoadAddress(
716 target);
717 if (msg_forward)
718 m_msg_forward_addr = msg_forward->GetAddress().GetOpcodeLoadAddress(target);
719 if (msg_forward_stret)
720 m_msg_forward_stret_addr =
721 msg_forward_stret->GetAddress().GetOpcodeLoadAddress(target);
722
723 // FIXME: Do some kind of logging here.
724 if (m_impl_fn_addr == LLDB_INVALID_ADDRESS) {
725 // If we can't even find the ordinary get method implementation function,
726 // then we aren't going to be able to
727 // step through any method dispatches. Warn to that effect and get out of
728 // here.
729 if (process_sp->CanJIT()) {
730 process_sp->GetTarget().GetDebugger().GetErrorStream().Printf(
731 "Could not find implementation lookup function \"%s\""
732 " step in through ObjC method dispatch will not work.\n",
733 get_impl_name.AsCString());
734 }
735 return;
736 } else if (m_impl_stret_fn_addr == LLDB_INVALID_ADDRESS) {
737 // It there is no stret return lookup function, assume that it is the same
738 // as the straight lookup:
739 m_impl_stret_fn_addr = m_impl_fn_addr;
740 // Also we will use the version of the lookup code that doesn't rely on the
741 // stret version of the function.
742 m_lookup_implementation_function_code =
743 g_lookup_implementation_no_stret_function_code;
744 } else {
745 m_lookup_implementation_function_code =
746 g_lookup_implementation_with_stret_function_code;
747 }
748
749 // Look up the addresses for the objc dispatch functions and cache
750 // them. For now I'm inspecting the symbol names dynamically to
751 // figure out how to dispatch to them. If it becomes more
752 // complicated than this we can turn the g_dispatch_functions char *
753 // array into a template table, and populate the DispatchFunction
754 // map from there.
755
756 for (size_t i = 0; i != llvm::array_lengthof(g_dispatch_functions); i++) {
757 ConstString name_const_str(g_dispatch_functions[i].name);
758 const Symbol *msgSend_symbol =
759 m_objc_module_sp->FindFirstSymbolWithNameAndType(name_const_str,
760 eSymbolTypeCode);
761 if (msgSend_symbol && msgSend_symbol->ValueIsAddress()) {
762 // FIXME: Make g_dispatch_functions static table of
763 // DispatchFunctions, and have the map be address->index.
764 // Problem is we also need to lookup the dispatch function. For
765 // now we could have a side table of stret & non-stret dispatch
766 // functions. If that's as complex as it gets, we're fine.
767
768 lldb::addr_t sym_addr =
769 msgSend_symbol->GetAddressRef().GetOpcodeLoadAddress(target);
770
771 m_msgSend_map.insert(std::pair<lldb::addr_t, int>(sym_addr, i));
772 }
773 }
774
775 // Similarly, cache the addresses of the "optimized dispatch" function.
776 for (size_t i = 0; i != llvm::array_lengthof(g_opt_dispatch_names); i++) {
777 ConstString name_const_str(g_opt_dispatch_names[i]);
778 const Symbol *msgSend_symbol =
779 m_objc_module_sp->FindFirstSymbolWithNameAndType(name_const_str,
780 eSymbolTypeCode);
781 if (msgSend_symbol && msgSend_symbol->ValueIsAddress()) {
782 lldb::addr_t sym_addr =
783 msgSend_symbol->GetAddressRef().GetOpcodeLoadAddress(target);
784
785 m_opt_dispatch_map.emplace(sym_addr, i);
786 }
787 }
788
789 // Build our vtable dispatch handler here:
790 m_vtables_up =
791 std::make_unique<AppleObjCVTables>(process_sp, m_objc_module_sp);
792 if (m_vtables_up)
793 m_vtables_up->ReadRegions();
794 }
795
796 lldb::addr_t
SetupDispatchFunction(Thread & thread,ValueList & dispatch_values)797 AppleObjCTrampolineHandler::SetupDispatchFunction(Thread &thread,
798 ValueList &dispatch_values) {
799 ThreadSP thread_sp(thread.shared_from_this());
800 ExecutionContext exe_ctx(thread_sp);
801 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
802
803 lldb::addr_t args_addr = LLDB_INVALID_ADDRESS;
804 FunctionCaller *impl_function_caller = nullptr;
805
806 // Scope for mutex locker:
807 {
808 std::lock_guard<std::mutex> guard(m_impl_function_mutex);
809
810 // First stage is to make the ClangUtility to hold our injected function:
811
812 if (!m_impl_code) {
813 if (m_lookup_implementation_function_code != nullptr) {
814 auto utility_fn_or_error = exe_ctx.GetTargetRef().CreateUtilityFunction(
815 m_lookup_implementation_function_code,
816 g_lookup_implementation_function_name, eLanguageTypeC, exe_ctx);
817 if (!utility_fn_or_error) {
818 LLDB_LOG_ERROR(
819 log, utility_fn_or_error.takeError(),
820 "Failed to get Utility Function for implementation lookup: {0}.");
821 return args_addr;
822 }
823 m_impl_code = std::move(*utility_fn_or_error);
824 } else {
825 LLDB_LOGF(log, "No method lookup implementation code.");
826 return LLDB_INVALID_ADDRESS;
827 }
828
829 // Next make the runner function for our implementation utility function.
830 TypeSystemClang *clang_ast_context = ScratchTypeSystemClang::GetForTarget(
831 thread.GetProcess()->GetTarget());
832 if (!clang_ast_context)
833 return LLDB_INVALID_ADDRESS;
834
835 CompilerType clang_void_ptr_type =
836 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
837 Status error;
838
839 impl_function_caller = m_impl_code->MakeFunctionCaller(
840 clang_void_ptr_type, dispatch_values, thread_sp, error);
841 if (error.Fail()) {
842 LLDB_LOGF(log,
843 "Error getting function caller for dispatch lookup: \"%s\".",
844 error.AsCString());
845 return args_addr;
846 }
847 } else {
848 impl_function_caller = m_impl_code->GetFunctionCaller();
849 }
850 }
851
852 // Now write down the argument values for this particular call.
853 // This looks like it might be a race condition if other threads
854 // were calling into here, but actually it isn't because we allocate
855 // a new args structure for this call by passing args_addr =
856 // LLDB_INVALID_ADDRESS...
857
858 DiagnosticManager diagnostics;
859 if (!impl_function_caller->WriteFunctionArguments(
860 exe_ctx, args_addr, dispatch_values, diagnostics)) {
861 if (log) {
862 LLDB_LOGF(log, "Error writing function arguments.");
863 diagnostics.Dump(log);
864 }
865 return args_addr;
866 }
867
868 return args_addr;
869 }
870
871 const AppleObjCTrampolineHandler::DispatchFunction *
FindDispatchFunction(lldb::addr_t addr)872 AppleObjCTrampolineHandler::FindDispatchFunction(lldb::addr_t addr) {
873 MsgsendMap::iterator pos;
874 pos = m_msgSend_map.find(addr);
875 if (pos != m_msgSend_map.end()) {
876 return &g_dispatch_functions[(*pos).second];
877 }
878 return nullptr;
879 }
880
881 void
ForEachDispatchFunction(std::function<void (lldb::addr_t,const DispatchFunction &)> callback)882 AppleObjCTrampolineHandler::ForEachDispatchFunction(
883 std::function<void(lldb::addr_t,
884 const DispatchFunction &)> callback) {
885 for (auto elem : m_msgSend_map) {
886 callback(elem.first, g_dispatch_functions[elem.second]);
887 }
888 }
889
890 ThreadPlanSP
GetStepThroughDispatchPlan(Thread & thread,bool stop_others)891 AppleObjCTrampolineHandler::GetStepThroughDispatchPlan(Thread &thread,
892 bool stop_others) {
893 ThreadPlanSP ret_plan_sp;
894 lldb::addr_t curr_pc = thread.GetRegisterContext()->GetPC();
895
896 DispatchFunction vtable_dispatch
897 = {"vtable", 0, false, false, DispatchFunction::eFixUpFixed};
898
899 // First step is to look and see if we are in one of the known ObjC
900 // dispatch functions. We've already compiled a table of same, so
901 // consult it.
902
903 const DispatchFunction *this_dispatch = FindDispatchFunction(curr_pc);
904
905 // Next check to see if we are in a vtable region:
906
907 if (!this_dispatch && m_vtables_up) {
908 uint32_t flags;
909 if (m_vtables_up->IsAddressInVTables(curr_pc, flags)) {
910 vtable_dispatch.stret_return =
911 (flags & AppleObjCVTables::eOBJC_TRAMPOLINE_STRET) ==
912 AppleObjCVTables::eOBJC_TRAMPOLINE_STRET;
913 this_dispatch = &vtable_dispatch;
914 }
915 }
916
917 if (this_dispatch) {
918 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
919
920 // We are decoding a method dispatch. First job is to pull the
921 // arguments out:
922
923 lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0);
924
925 const ABI *abi = nullptr;
926 ProcessSP process_sp(thread.CalculateProcess());
927 if (process_sp)
928 abi = process_sp->GetABI().get();
929 if (abi == nullptr)
930 return ret_plan_sp;
931
932 TargetSP target_sp(thread.CalculateTarget());
933
934 TypeSystemClang *clang_ast_context =
935 ScratchTypeSystemClang::GetForTarget(*target_sp);
936 if (!clang_ast_context)
937 return ret_plan_sp;
938
939 ValueList argument_values;
940 Value void_ptr_value;
941 CompilerType clang_void_ptr_type =
942 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
943 void_ptr_value.SetValueType(Value::eValueTypeScalar);
944 // void_ptr_value.SetContext (Value::eContextTypeClangType,
945 // clang_void_ptr_type);
946 void_ptr_value.SetCompilerType(clang_void_ptr_type);
947
948 int obj_index;
949 int sel_index;
950
951 // If this is a struct return dispatch, then the first argument is
952 // the return struct pointer, and the object is the second, and
953 // the selector is the third. Otherwise the object is the first
954 // and the selector the second.
955 if (this_dispatch->stret_return) {
956 obj_index = 1;
957 sel_index = 2;
958 argument_values.PushValue(void_ptr_value);
959 argument_values.PushValue(void_ptr_value);
960 argument_values.PushValue(void_ptr_value);
961 } else {
962 obj_index = 0;
963 sel_index = 1;
964 argument_values.PushValue(void_ptr_value);
965 argument_values.PushValue(void_ptr_value);
966 }
967
968 bool success = abi->GetArgumentValues(thread, argument_values);
969 if (!success)
970 return ret_plan_sp;
971
972 lldb::addr_t obj_addr =
973 argument_values.GetValueAtIndex(obj_index)->GetScalar().ULongLong();
974 if (obj_addr == 0x0) {
975 LLDB_LOGF(
976 log,
977 "Asked to step to dispatch to nil object, returning empty plan.");
978 return ret_plan_sp;
979 }
980
981 ExecutionContext exe_ctx(thread.shared_from_this());
982 Process *process = exe_ctx.GetProcessPtr();
983 // isa_addr will store the class pointer that the method is being
984 // dispatched to - so either the class directly or the super class
985 // if this is one of the objc_msgSendSuper flavors. That's mostly
986 // used to look up the class/selector pair in our cache.
987
988 lldb::addr_t isa_addr = LLDB_INVALID_ADDRESS;
989 lldb::addr_t sel_addr =
990 argument_values.GetValueAtIndex(sel_index)->GetScalar().ULongLong();
991
992 // Figure out the class this is being dispatched to and see if
993 // we've already cached this method call, If so we can push a
994 // run-to-address plan directly. Otherwise we have to figure out
995 // where the implementation lives.
996
997 if (this_dispatch->is_super) {
998 if (this_dispatch->is_super2) {
999 // In the objc_msgSendSuper2 case, we don't get the object
1000 // directly, we get a structure containing the object and the
1001 // class to which the super message is being sent. So we need
1002 // to dig the super out of the class and use that.
1003
1004 Value super_value(*(argument_values.GetValueAtIndex(obj_index)));
1005 super_value.GetScalar() += process->GetAddressByteSize();
1006 super_value.ResolveValue(&exe_ctx);
1007
1008 if (super_value.GetScalar().IsValid()) {
1009
1010 // isa_value now holds the class pointer. The second word of the
1011 // class pointer is the super-class pointer:
1012 super_value.GetScalar() += process->GetAddressByteSize();
1013 super_value.ResolveValue(&exe_ctx);
1014 if (super_value.GetScalar().IsValid())
1015 isa_addr = super_value.GetScalar().ULongLong();
1016 else {
1017 LLDB_LOGF(log, "Failed to extract the super class value from the "
1018 "class in objc_super.");
1019 }
1020 } else {
1021 LLDB_LOGF(log, "Failed to extract the class value from objc_super.");
1022 }
1023 } else {
1024 // In the objc_msgSendSuper case, we don't get the object
1025 // directly, we get a two element structure containing the
1026 // object and the super class to which the super message is
1027 // being sent. So the class we want is the second element of
1028 // this structure.
1029
1030 Value super_value(*(argument_values.GetValueAtIndex(obj_index)));
1031 super_value.GetScalar() += process->GetAddressByteSize();
1032 super_value.ResolveValue(&exe_ctx);
1033
1034 if (super_value.GetScalar().IsValid()) {
1035 isa_addr = super_value.GetScalar().ULongLong();
1036 } else {
1037 LLDB_LOGF(log, "Failed to extract the class value from objc_super.");
1038 }
1039 }
1040 } else {
1041 // In the direct dispatch case, the object->isa is the class pointer we
1042 // want.
1043
1044 // This is a little cheesy, but since object->isa is the first field,
1045 // making the object value a load address value and resolving it will get
1046 // the pointer sized data pointed to by that value...
1047
1048 // Note, it isn't a fatal error not to be able to get the
1049 // address from the object, since this might be a "tagged
1050 // pointer" which isn't a real object, but rather some word
1051 // length encoded dingus.
1052
1053 Value isa_value(*(argument_values.GetValueAtIndex(obj_index)));
1054
1055 isa_value.SetValueType(Value::eValueTypeLoadAddress);
1056 isa_value.ResolveValue(&exe_ctx);
1057 if (isa_value.GetScalar().IsValid()) {
1058 isa_addr = isa_value.GetScalar().ULongLong();
1059 } else {
1060 LLDB_LOGF(log, "Failed to extract the isa value from object.");
1061 }
1062 }
1063
1064 // Okay, we've got the address of the class for which we're resolving this,
1065 // let's see if it's in our cache:
1066 lldb::addr_t impl_addr = LLDB_INVALID_ADDRESS;
1067
1068 if (isa_addr != LLDB_INVALID_ADDRESS) {
1069 if (log) {
1070 LLDB_LOGF(log,
1071 "Resolving call for class - 0x%" PRIx64
1072 " and selector - 0x%" PRIx64,
1073 isa_addr, sel_addr);
1074 }
1075 ObjCLanguageRuntime *objc_runtime =
1076 ObjCLanguageRuntime::Get(*thread.GetProcess());
1077 assert(objc_runtime != nullptr);
1078
1079 impl_addr = objc_runtime->LookupInMethodCache(isa_addr, sel_addr);
1080 }
1081
1082 if (impl_addr != LLDB_INVALID_ADDRESS) {
1083 // Yup, it was in the cache, so we can run to that address directly.
1084
1085 LLDB_LOGF(log, "Found implementation address in cache: 0x%" PRIx64,
1086 impl_addr);
1087
1088 ret_plan_sp = std::make_shared<ThreadPlanRunToAddress>(thread, impl_addr,
1089 stop_others);
1090 } else {
1091 // We haven't seen this class/selector pair yet. Look it up.
1092 StreamString errors;
1093 Address impl_code_address;
1094
1095 ValueList dispatch_values;
1096
1097 // We've will inject a little function in the target that takes the
1098 // object, selector and some flags,
1099 // and figures out the implementation. Looks like:
1100 // void *__lldb_objc_find_implementation_for_selector (void *object,
1101 // void *sel,
1102 // int is_stret,
1103 // int is_super,
1104 // int is_super2,
1105 // int is_fixup,
1106 // int is_fixed,
1107 // int debug)
1108 // So set up the arguments for that call.
1109
1110 dispatch_values.PushValue(*(argument_values.GetValueAtIndex(obj_index)));
1111 dispatch_values.PushValue(*(argument_values.GetValueAtIndex(sel_index)));
1112
1113 Value flag_value;
1114 CompilerType clang_int_type =
1115 clang_ast_context->GetBuiltinTypeForEncodingAndBitSize(
1116 lldb::eEncodingSint, 32);
1117 flag_value.SetValueType(Value::eValueTypeScalar);
1118 // flag_value.SetContext (Value::eContextTypeClangType, clang_int_type);
1119 flag_value.SetCompilerType(clang_int_type);
1120
1121 if (this_dispatch->stret_return)
1122 flag_value.GetScalar() = 1;
1123 else
1124 flag_value.GetScalar() = 0;
1125 dispatch_values.PushValue(flag_value);
1126
1127 if (this_dispatch->is_super)
1128 flag_value.GetScalar() = 1;
1129 else
1130 flag_value.GetScalar() = 0;
1131 dispatch_values.PushValue(flag_value);
1132
1133 if (this_dispatch->is_super2)
1134 flag_value.GetScalar() = 1;
1135 else
1136 flag_value.GetScalar() = 0;
1137 dispatch_values.PushValue(flag_value);
1138
1139 switch (this_dispatch->fixedup) {
1140 case DispatchFunction::eFixUpNone:
1141 flag_value.GetScalar() = 0;
1142 dispatch_values.PushValue(flag_value);
1143 dispatch_values.PushValue(flag_value);
1144 break;
1145 case DispatchFunction::eFixUpFixed:
1146 flag_value.GetScalar() = 1;
1147 dispatch_values.PushValue(flag_value);
1148 flag_value.GetScalar() = 1;
1149 dispatch_values.PushValue(flag_value);
1150 break;
1151 case DispatchFunction::eFixUpToFix:
1152 flag_value.GetScalar() = 1;
1153 dispatch_values.PushValue(flag_value);
1154 flag_value.GetScalar() = 0;
1155 dispatch_values.PushValue(flag_value);
1156 break;
1157 }
1158 if (log && log->GetVerbose())
1159 flag_value.GetScalar() = 1;
1160 else
1161 flag_value.GetScalar() = 0; // FIXME - Set to 0 when debugging is done.
1162 dispatch_values.PushValue(flag_value);
1163
1164 // The step through code might have to fill in the cache, so it
1165 // is not safe to run only one thread. So we override the
1166 // stop_others value passed in to us here:
1167 const bool trampoline_stop_others = false;
1168 ret_plan_sp = std::make_shared<AppleThreadPlanStepThroughObjCTrampoline>(
1169 thread, *this, dispatch_values, isa_addr, sel_addr,
1170 trampoline_stop_others);
1171 if (log) {
1172 StreamString s;
1173 ret_plan_sp->GetDescription(&s, eDescriptionLevelFull);
1174 LLDB_LOGF(log, "Using ObjC step plan: %s.\n", s.GetData());
1175 }
1176 }
1177 }
1178
1179 // Finally, check if we have hit an "optimized dispatch" function. This will
1180 // either directly call the base implementation or dispatch an objc_msgSend
1181 // if the method has been overridden. So we just do a "step in/step out",
1182 // setting a breakpoint on objc_msgSend, and if we hit the msgSend, we
1183 // will automatically step in again. That's the job of the
1184 // AppleThreadPlanStepThroughDirectDispatch.
1185 if (!this_dispatch && !ret_plan_sp) {
1186 MsgsendMap::iterator pos;
1187 pos = m_opt_dispatch_map.find(curr_pc);
1188 if (pos != m_opt_dispatch_map.end()) {
1189
1190 const char *opt_name = g_opt_dispatch_names[(*pos).second];
1191
1192 bool trampoline_stop_others = false;
1193 LazyBool step_in_should_stop = eLazyBoolCalculate;
1194 ret_plan_sp = std::make_shared<AppleThreadPlanStepThroughDirectDispatch> (
1195 thread, *this, opt_name, trampoline_stop_others, step_in_should_stop);
1196 }
1197 }
1198
1199 return ret_plan_sp;
1200 }
1201
1202 FunctionCaller *
GetLookupImplementationFunctionCaller()1203 AppleObjCTrampolineHandler::GetLookupImplementationFunctionCaller() {
1204 return m_impl_code->GetFunctionCaller();
1205 }
1206