1 //===-- SystemRuntimeMacOSX.cpp ---------------------------------*- C++ -*-===//
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 "Plugins/Process/Utility/HistoryThread.h"
10 #include "lldb/Breakpoint/StoppointCallbackContext.h"
11 #include "lldb/Core/Module.h"
12 #include "lldb/Core/ModuleSpec.h"
13 #include "lldb/Core/PluginManager.h"
14 #include "lldb/Core/Section.h"
15 #include "lldb/Symbol/ClangASTContext.h"
16 #include "lldb/Symbol/ObjectFile.h"
17 #include "lldb/Symbol/SymbolContext.h"
18 #include "lldb/Target/Process.h"
19 #include "lldb/Target/ProcessStructReader.h"
20 #include "lldb/Target/Queue.h"
21 #include "lldb/Target/QueueList.h"
22 #include "lldb/Target/Target.h"
23 #include "lldb/Target/Thread.h"
24 #include "lldb/Utility/DataBufferHeap.h"
25 #include "lldb/Utility/DataExtractor.h"
26 #include "lldb/Utility/FileSpec.h"
27 #include "lldb/Utility/Log.h"
28 #include "lldb/Utility/StreamString.h"
29 
30 #include "SystemRuntimeMacOSX.h"
31 
32 #include <memory>
33 
34 using namespace lldb;
35 using namespace lldb_private;
36 
37 // Create an instance of this class. This function is filled into the plugin
38 // info class that gets handed out by the plugin factory and allows the lldb to
39 // instantiate an instance of this class.
40 SystemRuntime *SystemRuntimeMacOSX::CreateInstance(Process *process) {
41   bool create = false;
42   if (!create) {
43     create = true;
44     Module *exe_module = process->GetTarget().GetExecutableModulePointer();
45     if (exe_module) {
46       ObjectFile *object_file = exe_module->GetObjectFile();
47       if (object_file) {
48         create = (object_file->GetStrata() == ObjectFile::eStrataUser);
49       }
50     }
51 
52     if (create) {
53       const llvm::Triple &triple_ref =
54           process->GetTarget().GetArchitecture().GetTriple();
55       switch (triple_ref.getOS()) {
56       case llvm::Triple::Darwin:
57       case llvm::Triple::MacOSX:
58       case llvm::Triple::IOS:
59       case llvm::Triple::TvOS:
60       case llvm::Triple::WatchOS:
61       // NEED_BRIDGEOS_TRIPLE case llvm::Triple::BridgeOS:
62         create = triple_ref.getVendor() == llvm::Triple::Apple;
63         break;
64       default:
65         create = false;
66         break;
67       }
68     }
69   }
70 
71   if (create)
72     return new SystemRuntimeMacOSX(process);
73   return nullptr;
74 }
75 
76 // Constructor
77 SystemRuntimeMacOSX::SystemRuntimeMacOSX(Process *process)
78     : SystemRuntime(process), m_break_id(LLDB_INVALID_BREAK_ID), m_mutex(),
79       m_get_queues_handler(process), m_get_pending_items_handler(process),
80       m_get_item_info_handler(process), m_get_thread_item_info_handler(process),
81       m_page_to_free(LLDB_INVALID_ADDRESS), m_page_to_free_size(0),
82       m_lib_backtrace_recording_info(),
83       m_dispatch_queue_offsets_addr(LLDB_INVALID_ADDRESS),
84       m_libdispatch_offsets(),
85       m_libpthread_layout_offsets_addr(LLDB_INVALID_ADDRESS),
86       m_libpthread_offsets(), m_dispatch_tsd_indexes_addr(LLDB_INVALID_ADDRESS),
87       m_libdispatch_tsd_indexes(),
88       m_dispatch_voucher_offsets_addr(LLDB_INVALID_ADDRESS),
89       m_libdispatch_voucher_offsets() {}
90 
91 // Destructor
92 SystemRuntimeMacOSX::~SystemRuntimeMacOSX() { Clear(true); }
93 
94 void SystemRuntimeMacOSX::Detach() {
95   m_get_queues_handler.Detach();
96   m_get_pending_items_handler.Detach();
97   m_get_item_info_handler.Detach();
98   m_get_thread_item_info_handler.Detach();
99 }
100 
101 // Clear out the state of this class.
102 void SystemRuntimeMacOSX::Clear(bool clear_process) {
103   std::lock_guard<std::recursive_mutex> guard(m_mutex);
104 
105   if (m_process->IsAlive() && LLDB_BREAK_ID_IS_VALID(m_break_id))
106     m_process->ClearBreakpointSiteByID(m_break_id);
107 
108   if (clear_process)
109     m_process = nullptr;
110   m_break_id = LLDB_INVALID_BREAK_ID;
111 }
112 
113 std::string
114 SystemRuntimeMacOSX::GetQueueNameFromThreadQAddress(addr_t dispatch_qaddr) {
115   std::string dispatch_queue_name;
116   if (dispatch_qaddr == LLDB_INVALID_ADDRESS || dispatch_qaddr == 0)
117     return "";
118 
119   ReadLibdispatchOffsets();
120   if (m_libdispatch_offsets.IsValid()) {
121     // dispatch_qaddr is from a thread_info(THREAD_IDENTIFIER_INFO) call for a
122     // thread - deref it to get the address of the dispatch_queue_t structure
123     // for this thread's queue.
124     Status error;
125     addr_t dispatch_queue_addr =
126         m_process->ReadPointerFromMemory(dispatch_qaddr, error);
127     if (error.Success()) {
128       if (m_libdispatch_offsets.dqo_version >= 4) {
129         // libdispatch versions 4+, pointer to dispatch name is in the queue
130         // structure.
131         addr_t pointer_to_label_address =
132             dispatch_queue_addr + m_libdispatch_offsets.dqo_label;
133         addr_t label_addr =
134             m_process->ReadPointerFromMemory(pointer_to_label_address, error);
135         if (error.Success()) {
136           m_process->ReadCStringFromMemory(label_addr, dispatch_queue_name,
137                                            error);
138         }
139       } else {
140         // libdispatch versions 1-3, dispatch name is a fixed width char array
141         // in the queue structure.
142         addr_t label_addr =
143             dispatch_queue_addr + m_libdispatch_offsets.dqo_label;
144         dispatch_queue_name.resize(m_libdispatch_offsets.dqo_label_size, '\0');
145         size_t bytes_read =
146             m_process->ReadMemory(label_addr, &dispatch_queue_name[0],
147                                   m_libdispatch_offsets.dqo_label_size, error);
148         if (bytes_read < m_libdispatch_offsets.dqo_label_size)
149           dispatch_queue_name.erase(bytes_read);
150       }
151     }
152   }
153   return dispatch_queue_name;
154 }
155 
156 lldb::addr_t SystemRuntimeMacOSX::GetLibdispatchQueueAddressFromThreadQAddress(
157     addr_t dispatch_qaddr) {
158   addr_t libdispatch_queue_t_address = LLDB_INVALID_ADDRESS;
159   Status error;
160   libdispatch_queue_t_address =
161       m_process->ReadPointerFromMemory(dispatch_qaddr, error);
162   if (!error.Success()) {
163     libdispatch_queue_t_address = LLDB_INVALID_ADDRESS;
164   }
165   return libdispatch_queue_t_address;
166 }
167 
168 lldb::QueueKind SystemRuntimeMacOSX::GetQueueKind(addr_t dispatch_queue_addr) {
169   if (dispatch_queue_addr == LLDB_INVALID_ADDRESS || dispatch_queue_addr == 0)
170     return eQueueKindUnknown;
171 
172   QueueKind kind = eQueueKindUnknown;
173   ReadLibdispatchOffsets();
174   if (m_libdispatch_offsets.IsValid() &&
175       m_libdispatch_offsets.dqo_version >= 4) {
176     Status error;
177     uint64_t width = m_process->ReadUnsignedIntegerFromMemory(
178         dispatch_queue_addr + m_libdispatch_offsets.dqo_width,
179         m_libdispatch_offsets.dqo_width_size, 0, error);
180     if (error.Success()) {
181       if (width == 1) {
182         kind = eQueueKindSerial;
183       }
184       if (width > 1) {
185         kind = eQueueKindConcurrent;
186       }
187     }
188   }
189   return kind;
190 }
191 
192 void SystemRuntimeMacOSX::AddThreadExtendedInfoPacketHints(
193     lldb_private::StructuredData::ObjectSP dict_sp) {
194   StructuredData::Dictionary *dict = dict_sp->GetAsDictionary();
195   if (dict) {
196     ReadLibpthreadOffsets();
197     if (m_libpthread_offsets.IsValid()) {
198       dict->AddIntegerItem("plo_pthread_tsd_base_offset",
199                            m_libpthread_offsets.plo_pthread_tsd_base_offset);
200       dict->AddIntegerItem(
201           "plo_pthread_tsd_base_address_offset",
202           m_libpthread_offsets.plo_pthread_tsd_base_address_offset);
203       dict->AddIntegerItem("plo_pthread_tsd_entry_size",
204                            m_libpthread_offsets.plo_pthread_tsd_entry_size);
205     }
206 
207     ReadLibdispatchTSDIndexes();
208     if (m_libdispatch_tsd_indexes.IsValid()) {
209       dict->AddIntegerItem("dti_queue_index",
210                            m_libdispatch_tsd_indexes.dti_queue_index);
211       dict->AddIntegerItem("dti_voucher_index",
212                            m_libdispatch_tsd_indexes.dti_voucher_index);
213       dict->AddIntegerItem("dti_qos_class_index",
214                            m_libdispatch_tsd_indexes.dti_qos_class_index);
215     }
216   }
217 }
218 
219 bool SystemRuntimeMacOSX::SafeToCallFunctionsOnThisThread(ThreadSP thread_sp) {
220   if (thread_sp && thread_sp->GetStackFrameCount() > 0 &&
221       thread_sp->GetFrameWithConcreteFrameIndex(0)) {
222     const SymbolContext sym_ctx(
223         thread_sp->GetFrameWithConcreteFrameIndex(0)->GetSymbolContext(
224             eSymbolContextSymbol));
225     static ConstString g_select_symbol("__select");
226     if (sym_ctx.GetFunctionName() == g_select_symbol) {
227       return false;
228     }
229   }
230   return true;
231 }
232 
233 lldb::queue_id_t
234 SystemRuntimeMacOSX::GetQueueIDFromThreadQAddress(lldb::addr_t dispatch_qaddr) {
235   queue_id_t queue_id = LLDB_INVALID_QUEUE_ID;
236 
237   if (dispatch_qaddr == LLDB_INVALID_ADDRESS || dispatch_qaddr == 0)
238     return queue_id;
239 
240   ReadLibdispatchOffsets();
241   if (m_libdispatch_offsets.IsValid()) {
242     // dispatch_qaddr is from a thread_info(THREAD_IDENTIFIER_INFO) call for a
243     // thread - deref it to get the address of the dispatch_queue_t structure
244     // for this thread's queue.
245     Status error;
246     uint64_t dispatch_queue_addr =
247         m_process->ReadPointerFromMemory(dispatch_qaddr, error);
248     if (error.Success()) {
249       addr_t serialnum_address =
250           dispatch_queue_addr + m_libdispatch_offsets.dqo_serialnum;
251       queue_id_t serialnum = m_process->ReadUnsignedIntegerFromMemory(
252           serialnum_address, m_libdispatch_offsets.dqo_serialnum_size,
253           LLDB_INVALID_QUEUE_ID, error);
254       if (error.Success()) {
255         queue_id = serialnum;
256       }
257     }
258   }
259 
260   return queue_id;
261 }
262 
263 void SystemRuntimeMacOSX::ReadLibdispatchOffsetsAddress() {
264   if (m_dispatch_queue_offsets_addr != LLDB_INVALID_ADDRESS)
265     return;
266 
267   static ConstString g_dispatch_queue_offsets_symbol_name(
268       "dispatch_queue_offsets");
269   const Symbol *dispatch_queue_offsets_symbol = nullptr;
270 
271   // libdispatch symbols were in libSystem.B.dylib up through Mac OS X 10.6
272   // ("Snow Leopard")
273   ModuleSpec libSystem_module_spec(FileSpec("libSystem.B.dylib"));
274   ModuleSP module_sp(m_process->GetTarget().GetImages().FindFirstModule(
275       libSystem_module_spec));
276   if (module_sp)
277     dispatch_queue_offsets_symbol = module_sp->FindFirstSymbolWithNameAndType(
278         g_dispatch_queue_offsets_symbol_name, eSymbolTypeData);
279 
280   // libdispatch symbols are in their own dylib as of Mac OS X 10.7 ("Lion")
281   // and later
282   if (dispatch_queue_offsets_symbol == nullptr) {
283     ModuleSpec libdispatch_module_spec(FileSpec("libdispatch.dylib"));
284     module_sp = m_process->GetTarget().GetImages().FindFirstModule(
285         libdispatch_module_spec);
286     if (module_sp)
287       dispatch_queue_offsets_symbol = module_sp->FindFirstSymbolWithNameAndType(
288           g_dispatch_queue_offsets_symbol_name, eSymbolTypeData);
289   }
290   if (dispatch_queue_offsets_symbol)
291     m_dispatch_queue_offsets_addr =
292         dispatch_queue_offsets_symbol->GetLoadAddress(&m_process->GetTarget());
293 }
294 
295 void SystemRuntimeMacOSX::ReadLibdispatchOffsets() {
296   if (m_libdispatch_offsets.IsValid())
297     return;
298 
299   ReadLibdispatchOffsetsAddress();
300 
301   uint8_t memory_buffer[sizeof(struct LibdispatchOffsets)];
302   DataExtractor data(memory_buffer, sizeof(memory_buffer),
303                      m_process->GetByteOrder(),
304                      m_process->GetAddressByteSize());
305 
306   Status error;
307   if (m_process->ReadMemory(m_dispatch_queue_offsets_addr, memory_buffer,
308                             sizeof(memory_buffer),
309                             error) == sizeof(memory_buffer)) {
310     lldb::offset_t data_offset = 0;
311 
312     // The struct LibdispatchOffsets is a series of uint16_t's - extract them
313     // all in one big go.
314     data.GetU16(&data_offset, &m_libdispatch_offsets.dqo_version,
315                 sizeof(struct LibdispatchOffsets) / sizeof(uint16_t));
316   }
317 }
318 
319 void SystemRuntimeMacOSX::ReadLibpthreadOffsetsAddress() {
320   if (m_libpthread_layout_offsets_addr != LLDB_INVALID_ADDRESS)
321     return;
322 
323   static ConstString g_libpthread_layout_offsets_symbol_name(
324       "pthread_layout_offsets");
325   const Symbol *libpthread_layout_offsets_symbol = nullptr;
326 
327   ModuleSpec libpthread_module_spec(FileSpec("libsystem_pthread.dylib"));
328   ModuleSP module_sp(m_process->GetTarget().GetImages().FindFirstModule(
329       libpthread_module_spec));
330   if (module_sp) {
331     libpthread_layout_offsets_symbol =
332         module_sp->FindFirstSymbolWithNameAndType(
333             g_libpthread_layout_offsets_symbol_name, eSymbolTypeData);
334     if (libpthread_layout_offsets_symbol) {
335       m_libpthread_layout_offsets_addr =
336           libpthread_layout_offsets_symbol->GetLoadAddress(
337               &m_process->GetTarget());
338     }
339   }
340 }
341 
342 void SystemRuntimeMacOSX::ReadLibpthreadOffsets() {
343   if (m_libpthread_offsets.IsValid())
344     return;
345 
346   ReadLibpthreadOffsetsAddress();
347 
348   if (m_libpthread_layout_offsets_addr != LLDB_INVALID_ADDRESS) {
349     uint8_t memory_buffer[sizeof(struct LibpthreadOffsets)];
350     DataExtractor data(memory_buffer, sizeof(memory_buffer),
351                        m_process->GetByteOrder(),
352                        m_process->GetAddressByteSize());
353     Status error;
354     if (m_process->ReadMemory(m_libpthread_layout_offsets_addr, memory_buffer,
355                               sizeof(memory_buffer),
356                               error) == sizeof(memory_buffer)) {
357       lldb::offset_t data_offset = 0;
358 
359       // The struct LibpthreadOffsets is a series of uint16_t's - extract them
360       // all in one big go.
361       data.GetU16(&data_offset, &m_libpthread_offsets.plo_version,
362                   sizeof(struct LibpthreadOffsets) / sizeof(uint16_t));
363     }
364   }
365 }
366 
367 void SystemRuntimeMacOSX::ReadLibdispatchTSDIndexesAddress() {
368   if (m_dispatch_tsd_indexes_addr != LLDB_INVALID_ADDRESS)
369     return;
370 
371   static ConstString g_libdispatch_tsd_indexes_symbol_name(
372       "dispatch_tsd_indexes");
373   const Symbol *libdispatch_tsd_indexes_symbol = nullptr;
374 
375   ModuleSpec libpthread_module_spec(FileSpec("libdispatch.dylib"));
376   ModuleSP module_sp(m_process->GetTarget().GetImages().FindFirstModule(
377       libpthread_module_spec));
378   if (module_sp) {
379     libdispatch_tsd_indexes_symbol = module_sp->FindFirstSymbolWithNameAndType(
380         g_libdispatch_tsd_indexes_symbol_name, eSymbolTypeData);
381     if (libdispatch_tsd_indexes_symbol) {
382       m_dispatch_tsd_indexes_addr =
383           libdispatch_tsd_indexes_symbol->GetLoadAddress(
384               &m_process->GetTarget());
385     }
386   }
387 }
388 
389 void SystemRuntimeMacOSX::ReadLibdispatchTSDIndexes() {
390   if (m_libdispatch_tsd_indexes.IsValid())
391     return;
392 
393   ReadLibdispatchTSDIndexesAddress();
394 
395   if (m_dispatch_tsd_indexes_addr != LLDB_INVALID_ADDRESS) {
396 
397 // We don't need to check the version number right now, it will be at least 2,
398 // but keep this code around to fetch just the version # for the future where
399 // we need to fetch alternate versions of the struct.
400 #if 0
401         uint16_t dti_version = 2;
402         Address dti_struct_addr;
403         if (m_process->GetTarget().ResolveLoadAddress (m_dispatch_tsd_indexes_addr, dti_struct_addr))
404         {
405             Status error;
406             uint16_t version = m_process->GetTarget().ReadUnsignedIntegerFromMemory (dti_struct_addr, false, 2, UINT16_MAX, error);
407             if (error.Success() && dti_version != UINT16_MAX)
408             {
409                 dti_version = version;
410             }
411         }
412 #endif
413 
414     ClangASTContext *ast_ctx =
415         m_process->GetTarget().GetScratchClangASTContext();
416     if (ast_ctx->getASTContext() &&
417         m_dispatch_tsd_indexes_addr != LLDB_INVALID_ADDRESS) {
418       CompilerType uint16 =
419           ast_ctx->GetBuiltinTypeForEncodingAndBitSize(eEncodingUint, 16);
420       CompilerType dispatch_tsd_indexes_s = ast_ctx->CreateRecordType(
421           nullptr, lldb::eAccessPublic, "__lldb_dispatch_tsd_indexes_s",
422           clang::TTK_Struct, lldb::eLanguageTypeC);
423 
424       ClangASTContext::StartTagDeclarationDefinition(dispatch_tsd_indexes_s);
425       ClangASTContext::AddFieldToRecordType(dispatch_tsd_indexes_s,
426                                             "dti_version", uint16,
427                                             lldb::eAccessPublic, 0);
428       ClangASTContext::AddFieldToRecordType(dispatch_tsd_indexes_s,
429                                             "dti_queue_index", uint16,
430                                             lldb::eAccessPublic, 0);
431       ClangASTContext::AddFieldToRecordType(dispatch_tsd_indexes_s,
432                                             "dti_voucher_index", uint16,
433                                             lldb::eAccessPublic, 0);
434       ClangASTContext::AddFieldToRecordType(dispatch_tsd_indexes_s,
435                                             "dti_qos_class_index", uint16,
436                                             lldb::eAccessPublic, 0);
437       ClangASTContext::CompleteTagDeclarationDefinition(dispatch_tsd_indexes_s);
438 
439       ProcessStructReader struct_reader(m_process, m_dispatch_tsd_indexes_addr,
440                                         dispatch_tsd_indexes_s);
441 
442       m_libdispatch_tsd_indexes.dti_version =
443           struct_reader.GetField<uint16_t>(ConstString("dti_version"));
444       m_libdispatch_tsd_indexes.dti_queue_index =
445           struct_reader.GetField<uint16_t>(ConstString("dti_queue_index"));
446       m_libdispatch_tsd_indexes.dti_voucher_index =
447           struct_reader.GetField<uint16_t>(ConstString("dti_voucher_index"));
448       m_libdispatch_tsd_indexes.dti_qos_class_index =
449           struct_reader.GetField<uint16_t>(ConstString("dti_qos_class_index"));
450     }
451   }
452 }
453 
454 ThreadSP SystemRuntimeMacOSX::GetExtendedBacktraceThread(ThreadSP real_thread,
455                                                          ConstString type) {
456   ThreadSP originating_thread_sp;
457   if (BacktraceRecordingHeadersInitialized() && type == "libdispatch") {
458     Status error;
459 
460     // real_thread is either an actual, live thread (in which case we need to
461     // call into libBacktraceRecording to find its originator) or it is an
462     // extended backtrace itself, in which case we get the token from it and
463     // call into libBacktraceRecording to find the originator of that token.
464 
465     if (real_thread->GetExtendedBacktraceToken() != LLDB_INVALID_ADDRESS) {
466       originating_thread_sp = GetExtendedBacktraceFromItemRef(
467           real_thread->GetExtendedBacktraceToken());
468     } else {
469       ThreadSP cur_thread_sp(
470           m_process->GetThreadList().GetExpressionExecutionThread());
471       AppleGetThreadItemInfoHandler::GetThreadItemInfoReturnInfo ret =
472           m_get_thread_item_info_handler.GetThreadItemInfo(
473               *cur_thread_sp.get(), real_thread->GetID(), m_page_to_free,
474               m_page_to_free_size, error);
475       m_page_to_free = LLDB_INVALID_ADDRESS;
476       m_page_to_free_size = 0;
477       if (ret.item_buffer_ptr != 0 &&
478           ret.item_buffer_ptr != LLDB_INVALID_ADDRESS &&
479           ret.item_buffer_size > 0) {
480         DataBufferHeap data(ret.item_buffer_size, 0);
481         if (m_process->ReadMemory(ret.item_buffer_ptr, data.GetBytes(),
482                                   ret.item_buffer_size, error) &&
483             error.Success()) {
484           DataExtractor extractor(data.GetBytes(), data.GetByteSize(),
485                                   m_process->GetByteOrder(),
486                                   m_process->GetAddressByteSize());
487           ItemInfo item = ExtractItemInfoFromBuffer(extractor);
488           originating_thread_sp = std::make_shared<HistoryThread>(
489               *m_process, item.enqueuing_thread_id, item.enqueuing_callstack);
490           originating_thread_sp->SetExtendedBacktraceToken(
491               item.item_that_enqueued_this);
492           originating_thread_sp->SetQueueName(
493               item.enqueuing_queue_label.c_str());
494           originating_thread_sp->SetQueueID(item.enqueuing_queue_serialnum);
495           //                    originating_thread_sp->SetThreadName
496           //                    (item.enqueuing_thread_label.c_str());
497         }
498         m_page_to_free = ret.item_buffer_ptr;
499         m_page_to_free_size = ret.item_buffer_size;
500       }
501     }
502   }
503   return originating_thread_sp;
504 }
505 
506 ThreadSP
507 SystemRuntimeMacOSX::GetExtendedBacktraceFromItemRef(lldb::addr_t item_ref) {
508   ThreadSP return_thread_sp;
509 
510   AppleGetItemInfoHandler::GetItemInfoReturnInfo ret;
511   ThreadSP cur_thread_sp(
512       m_process->GetThreadList().GetExpressionExecutionThread());
513   Status error;
514   ret = m_get_item_info_handler.GetItemInfo(*cur_thread_sp.get(), item_ref,
515                                             m_page_to_free, m_page_to_free_size,
516                                             error);
517   m_page_to_free = LLDB_INVALID_ADDRESS;
518   m_page_to_free_size = 0;
519   if (ret.item_buffer_ptr != 0 && ret.item_buffer_ptr != LLDB_INVALID_ADDRESS &&
520       ret.item_buffer_size > 0) {
521     DataBufferHeap data(ret.item_buffer_size, 0);
522     if (m_process->ReadMemory(ret.item_buffer_ptr, data.GetBytes(),
523                               ret.item_buffer_size, error) &&
524         error.Success()) {
525       DataExtractor extractor(data.GetBytes(), data.GetByteSize(),
526                               m_process->GetByteOrder(),
527                               m_process->GetAddressByteSize());
528       ItemInfo item = ExtractItemInfoFromBuffer(extractor);
529       return_thread_sp = std::make_shared<HistoryThread>(
530           *m_process, item.enqueuing_thread_id, item.enqueuing_callstack);
531       return_thread_sp->SetExtendedBacktraceToken(item.item_that_enqueued_this);
532       return_thread_sp->SetQueueName(item.enqueuing_queue_label.c_str());
533       return_thread_sp->SetQueueID(item.enqueuing_queue_serialnum);
534       //            return_thread_sp->SetThreadName
535       //            (item.enqueuing_thread_label.c_str());
536 
537       m_page_to_free = ret.item_buffer_ptr;
538       m_page_to_free_size = ret.item_buffer_size;
539     }
540   }
541   return return_thread_sp;
542 }
543 
544 ThreadSP
545 SystemRuntimeMacOSX::GetExtendedBacktraceForQueueItem(QueueItemSP queue_item_sp,
546                                                       ConstString type) {
547   ThreadSP extended_thread_sp;
548   if (type != "libdispatch")
549     return extended_thread_sp;
550 
551   extended_thread_sp = std::make_shared<HistoryThread>(
552       *m_process, queue_item_sp->GetEnqueueingThreadID(),
553       queue_item_sp->GetEnqueueingBacktrace());
554   extended_thread_sp->SetExtendedBacktraceToken(
555       queue_item_sp->GetItemThatEnqueuedThis());
556   extended_thread_sp->SetQueueName(queue_item_sp->GetQueueLabel().c_str());
557   extended_thread_sp->SetQueueID(queue_item_sp->GetEnqueueingQueueID());
558   //    extended_thread_sp->SetThreadName
559   //    (queue_item_sp->GetThreadLabel().c_str());
560 
561   return extended_thread_sp;
562 }
563 
564 /* Returns true if we were able to get the version / offset information
565  * out of libBacktraceRecording.  false means we were unable to retrieve
566  * this; the queue_info_version field will be 0.
567  */
568 
569 bool SystemRuntimeMacOSX::BacktraceRecordingHeadersInitialized() {
570   if (m_lib_backtrace_recording_info.queue_info_version != 0)
571     return true;
572 
573   addr_t queue_info_version_address = LLDB_INVALID_ADDRESS;
574   addr_t queue_info_data_offset_address = LLDB_INVALID_ADDRESS;
575   addr_t item_info_version_address = LLDB_INVALID_ADDRESS;
576   addr_t item_info_data_offset_address = LLDB_INVALID_ADDRESS;
577   Target &target = m_process->GetTarget();
578 
579   static ConstString introspection_dispatch_queue_info_version(
580       "__introspection_dispatch_queue_info_version");
581   SymbolContextList sc_list;
582   m_process->GetTarget().GetImages().FindSymbolsWithNameAndType(
583       introspection_dispatch_queue_info_version, eSymbolTypeData, sc_list);
584   if (!sc_list.IsEmpty()) {
585     SymbolContext sc;
586     sc_list.GetContextAtIndex(0, sc);
587     AddressRange addr_range;
588     sc.GetAddressRange(eSymbolContextSymbol, 0, false, addr_range);
589     queue_info_version_address =
590         addr_range.GetBaseAddress().GetLoadAddress(&target);
591   }
592   sc_list.Clear();
593 
594   static ConstString introspection_dispatch_queue_info_data_offset(
595       "__introspection_dispatch_queue_info_data_offset");
596   m_process->GetTarget().GetImages().FindSymbolsWithNameAndType(
597       introspection_dispatch_queue_info_data_offset, eSymbolTypeData, sc_list);
598   if (!sc_list.IsEmpty()) {
599     SymbolContext sc;
600     sc_list.GetContextAtIndex(0, sc);
601     AddressRange addr_range;
602     sc.GetAddressRange(eSymbolContextSymbol, 0, false, addr_range);
603     queue_info_data_offset_address =
604         addr_range.GetBaseAddress().GetLoadAddress(&target);
605   }
606   sc_list.Clear();
607 
608   static ConstString introspection_dispatch_item_info_version(
609       "__introspection_dispatch_item_info_version");
610   m_process->GetTarget().GetImages().FindSymbolsWithNameAndType(
611       introspection_dispatch_item_info_version, eSymbolTypeData, sc_list);
612   if (!sc_list.IsEmpty()) {
613     SymbolContext sc;
614     sc_list.GetContextAtIndex(0, sc);
615     AddressRange addr_range;
616     sc.GetAddressRange(eSymbolContextSymbol, 0, false, addr_range);
617     item_info_version_address =
618         addr_range.GetBaseAddress().GetLoadAddress(&target);
619   }
620   sc_list.Clear();
621 
622   static ConstString introspection_dispatch_item_info_data_offset(
623       "__introspection_dispatch_item_info_data_offset");
624   m_process->GetTarget().GetImages().FindSymbolsWithNameAndType(
625       introspection_dispatch_item_info_data_offset, eSymbolTypeData, sc_list);
626   if (!sc_list.IsEmpty()) {
627     SymbolContext sc;
628     sc_list.GetContextAtIndex(0, sc);
629     AddressRange addr_range;
630     sc.GetAddressRange(eSymbolContextSymbol, 0, false, addr_range);
631     item_info_data_offset_address =
632         addr_range.GetBaseAddress().GetLoadAddress(&target);
633   }
634 
635   if (queue_info_version_address != LLDB_INVALID_ADDRESS &&
636       queue_info_data_offset_address != LLDB_INVALID_ADDRESS &&
637       item_info_version_address != LLDB_INVALID_ADDRESS &&
638       item_info_data_offset_address != LLDB_INVALID_ADDRESS) {
639     Status error;
640     m_lib_backtrace_recording_info.queue_info_version =
641         m_process->ReadUnsignedIntegerFromMemory(queue_info_version_address, 2,
642                                                  0, error);
643     if (error.Success()) {
644       m_lib_backtrace_recording_info.queue_info_data_offset =
645           m_process->ReadUnsignedIntegerFromMemory(
646               queue_info_data_offset_address, 2, 0, error);
647       if (error.Success()) {
648         m_lib_backtrace_recording_info.item_info_version =
649             m_process->ReadUnsignedIntegerFromMemory(item_info_version_address,
650                                                      2, 0, error);
651         if (error.Success()) {
652           m_lib_backtrace_recording_info.item_info_data_offset =
653               m_process->ReadUnsignedIntegerFromMemory(
654                   item_info_data_offset_address, 2, 0, error);
655           if (!error.Success()) {
656             m_lib_backtrace_recording_info.queue_info_version = 0;
657           }
658         } else {
659           m_lib_backtrace_recording_info.queue_info_version = 0;
660         }
661       } else {
662         m_lib_backtrace_recording_info.queue_info_version = 0;
663       }
664     }
665   }
666 
667   return m_lib_backtrace_recording_info.queue_info_version != 0;
668 }
669 
670 const std::vector<ConstString> &
671 SystemRuntimeMacOSX::GetExtendedBacktraceTypes() {
672   if (m_types.size() == 0) {
673     m_types.push_back(ConstString("libdispatch"));
674     // We could have pthread as another type in the future if we have a way of
675     // gathering that information & it's useful to distinguish between them.
676   }
677   return m_types;
678 }
679 
680 void SystemRuntimeMacOSX::PopulateQueueList(
681     lldb_private::QueueList &queue_list) {
682   if (BacktraceRecordingHeadersInitialized()) {
683     AppleGetQueuesHandler::GetQueuesReturnInfo queue_info_pointer;
684     ThreadSP cur_thread_sp(
685         m_process->GetThreadList().GetExpressionExecutionThread());
686     if (cur_thread_sp) {
687       Status error;
688       queue_info_pointer = m_get_queues_handler.GetCurrentQueues(
689           *cur_thread_sp.get(), m_page_to_free, m_page_to_free_size, error);
690       m_page_to_free = LLDB_INVALID_ADDRESS;
691       m_page_to_free_size = 0;
692       if (error.Success()) {
693 
694         if (queue_info_pointer.count > 0 &&
695             queue_info_pointer.queues_buffer_size > 0 &&
696             queue_info_pointer.queues_buffer_ptr != 0 &&
697             queue_info_pointer.queues_buffer_ptr != LLDB_INVALID_ADDRESS) {
698           PopulateQueuesUsingLibBTR(queue_info_pointer.queues_buffer_ptr,
699                                     queue_info_pointer.queues_buffer_size,
700                                     queue_info_pointer.count, queue_list);
701         }
702       }
703     }
704   }
705 
706   // We either didn't have libBacktraceRecording (and need to create the queues
707   // list based on threads) or we did get the queues list from
708   // libBacktraceRecording but some special queues may not be included in its
709   // information.  This is needed because libBacktraceRecording will only list
710   // queues with pending or running items by default - but the magic com.apple
711   // .main-thread queue on thread 1 is always around.
712 
713   for (ThreadSP thread_sp : m_process->Threads()) {
714     if (thread_sp->GetAssociatedWithLibdispatchQueue() != eLazyBoolNo) {
715       if (thread_sp->GetQueueID() != LLDB_INVALID_QUEUE_ID) {
716         if (queue_list.FindQueueByID(thread_sp->GetQueueID()).get() ==
717             nullptr) {
718           QueueSP queue_sp(new Queue(m_process->shared_from_this(),
719                                      thread_sp->GetQueueID(),
720                                      thread_sp->GetQueueName()));
721           if (thread_sp->ThreadHasQueueInformation()) {
722             queue_sp->SetKind(thread_sp->GetQueueKind());
723             queue_sp->SetLibdispatchQueueAddress(
724                 thread_sp->GetQueueLibdispatchQueueAddress());
725             queue_list.AddQueue(queue_sp);
726           } else {
727             queue_sp->SetKind(
728                 GetQueueKind(thread_sp->GetQueueLibdispatchQueueAddress()));
729             queue_sp->SetLibdispatchQueueAddress(
730                 thread_sp->GetQueueLibdispatchQueueAddress());
731             queue_list.AddQueue(queue_sp);
732           }
733         }
734       }
735     }
736   }
737 }
738 
739 // Returns either an array of introspection_dispatch_item_info_ref's for the
740 // pending items on a queue or an array introspection_dispatch_item_info_ref's
741 // and code addresses for the pending items on a queue.  The information about
742 // each of these pending items then needs to be fetched individually by passing
743 // the ref to libBacktraceRecording.
744 
745 SystemRuntimeMacOSX::PendingItemsForQueue
746 SystemRuntimeMacOSX::GetPendingItemRefsForQueue(lldb::addr_t queue) {
747   PendingItemsForQueue pending_item_refs;
748   AppleGetPendingItemsHandler::GetPendingItemsReturnInfo pending_items_pointer;
749   ThreadSP cur_thread_sp(
750       m_process->GetThreadList().GetExpressionExecutionThread());
751   if (cur_thread_sp) {
752     Status error;
753     pending_items_pointer = m_get_pending_items_handler.GetPendingItems(
754         *cur_thread_sp.get(), queue, m_page_to_free, m_page_to_free_size,
755         error);
756     m_page_to_free = LLDB_INVALID_ADDRESS;
757     m_page_to_free_size = 0;
758     if (error.Success()) {
759       if (pending_items_pointer.count > 0 &&
760           pending_items_pointer.items_buffer_size > 0 &&
761           pending_items_pointer.items_buffer_ptr != 0 &&
762           pending_items_pointer.items_buffer_ptr != LLDB_INVALID_ADDRESS) {
763         DataBufferHeap data(pending_items_pointer.items_buffer_size, 0);
764         if (m_process->ReadMemory(
765                 pending_items_pointer.items_buffer_ptr, data.GetBytes(),
766                 pending_items_pointer.items_buffer_size, error)) {
767           DataExtractor extractor(data.GetBytes(), data.GetByteSize(),
768                                   m_process->GetByteOrder(),
769                                   m_process->GetAddressByteSize());
770 
771           // We either have an array of
772           //    void* item_ref
773           // (old style) or we have a structure returned which looks like
774           //
775           // struct introspection_dispatch_pending_item_info_s {
776           //   void *item_ref;
777           //   void *function_or_block;
778           // };
779           //
780           // struct introspection_dispatch_pending_items_array_s {
781           //   uint32_t version;
782           //   uint32_t size_of_item_info;
783           //   introspection_dispatch_pending_item_info_s items[];
784           //   }
785 
786           offset_t offset = 0;
787           int i = 0;
788           uint32_t version = extractor.GetU32(&offset);
789           if (version == 1) {
790             pending_item_refs.new_style = true;
791             uint32_t item_size = extractor.GetU32(&offset);
792             uint32_t start_of_array_offset = offset;
793             while (offset < pending_items_pointer.items_buffer_size &&
794                    static_cast<size_t>(i) < pending_items_pointer.count) {
795               offset = start_of_array_offset + (i * item_size);
796               ItemRefAndCodeAddress item;
797               item.item_ref = extractor.GetPointer(&offset);
798               item.code_address = extractor.GetPointer(&offset);
799               pending_item_refs.item_refs_and_code_addresses.push_back(item);
800               i++;
801             }
802           } else {
803             offset = 0;
804             pending_item_refs.new_style = false;
805             while (offset < pending_items_pointer.items_buffer_size &&
806                    static_cast<size_t>(i) < pending_items_pointer.count) {
807               ItemRefAndCodeAddress item;
808               item.item_ref = extractor.GetPointer(&offset);
809               item.code_address = LLDB_INVALID_ADDRESS;
810               pending_item_refs.item_refs_and_code_addresses.push_back(item);
811               i++;
812             }
813           }
814         }
815         m_page_to_free = pending_items_pointer.items_buffer_ptr;
816         m_page_to_free_size = pending_items_pointer.items_buffer_size;
817       }
818     }
819   }
820   return pending_item_refs;
821 }
822 
823 void SystemRuntimeMacOSX::PopulatePendingItemsForQueue(Queue *queue) {
824   if (BacktraceRecordingHeadersInitialized()) {
825     PendingItemsForQueue pending_item_refs =
826         GetPendingItemRefsForQueue(queue->GetLibdispatchQueueAddress());
827     for (ItemRefAndCodeAddress pending_item :
828          pending_item_refs.item_refs_and_code_addresses) {
829       Address addr;
830       m_process->GetTarget().ResolveLoadAddress(pending_item.code_address,
831                                                 addr);
832       QueueItemSP queue_item_sp(new QueueItem(queue->shared_from_this(),
833                                               m_process->shared_from_this(),
834                                               pending_item.item_ref, addr));
835       queue->PushPendingQueueItem(queue_item_sp);
836     }
837   }
838 }
839 
840 void SystemRuntimeMacOSX::CompleteQueueItem(QueueItem *queue_item,
841                                             addr_t item_ref) {
842   AppleGetItemInfoHandler::GetItemInfoReturnInfo ret;
843 
844   ThreadSP cur_thread_sp(
845       m_process->GetThreadList().GetExpressionExecutionThread());
846   Status error;
847   ret = m_get_item_info_handler.GetItemInfo(*cur_thread_sp.get(), item_ref,
848                                             m_page_to_free, m_page_to_free_size,
849                                             error);
850   m_page_to_free = LLDB_INVALID_ADDRESS;
851   m_page_to_free_size = 0;
852   if (ret.item_buffer_ptr != 0 && ret.item_buffer_ptr != LLDB_INVALID_ADDRESS &&
853       ret.item_buffer_size > 0) {
854     DataBufferHeap data(ret.item_buffer_size, 0);
855     if (m_process->ReadMemory(ret.item_buffer_ptr, data.GetBytes(),
856                               ret.item_buffer_size, error) &&
857         error.Success()) {
858       DataExtractor extractor(data.GetBytes(), data.GetByteSize(),
859                               m_process->GetByteOrder(),
860                               m_process->GetAddressByteSize());
861       ItemInfo item = ExtractItemInfoFromBuffer(extractor);
862       queue_item->SetItemThatEnqueuedThis(item.item_that_enqueued_this);
863       queue_item->SetEnqueueingThreadID(item.enqueuing_thread_id);
864       queue_item->SetEnqueueingQueueID(item.enqueuing_queue_serialnum);
865       queue_item->SetStopID(item.stop_id);
866       queue_item->SetEnqueueingBacktrace(item.enqueuing_callstack);
867       queue_item->SetThreadLabel(item.enqueuing_thread_label);
868       queue_item->SetQueueLabel(item.enqueuing_queue_label);
869       queue_item->SetTargetQueueLabel(item.target_queue_label);
870     }
871     m_page_to_free = ret.item_buffer_ptr;
872     m_page_to_free_size = ret.item_buffer_size;
873   }
874 }
875 
876 void SystemRuntimeMacOSX::PopulateQueuesUsingLibBTR(
877     lldb::addr_t queues_buffer, uint64_t queues_buffer_size, uint64_t count,
878     lldb_private::QueueList &queue_list) {
879   Status error;
880   DataBufferHeap data(queues_buffer_size, 0);
881   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME));
882   if (m_process->ReadMemory(queues_buffer, data.GetBytes(), queues_buffer_size,
883                             error) == queues_buffer_size &&
884       error.Success()) {
885     // We've read the information out of inferior memory; free it on the next
886     // call we make
887     m_page_to_free = queues_buffer;
888     m_page_to_free_size = queues_buffer_size;
889 
890     DataExtractor extractor(data.GetBytes(), data.GetByteSize(),
891                             m_process->GetByteOrder(),
892                             m_process->GetAddressByteSize());
893     offset_t offset = 0;
894     uint64_t queues_read = 0;
895 
896     // The information about the queues is stored in this format (v1): typedef
897     // struct introspection_dispatch_queue_info_s {
898     //     uint32_t offset_to_next;
899     //     dispatch_queue_t queue;
900     //     uint64_t serialnum;     // queue's serialnum in the process, as
901     //     provided by libdispatch
902     //     uint32_t running_work_items_count;
903     //     uint32_t pending_work_items_count;
904     //
905     //     char data[];     // Starting here, we have variable-length data:
906     //     // char queue_label[];
907     // } introspection_dispatch_queue_info_s;
908 
909     while (queues_read < count && offset < queues_buffer_size) {
910       offset_t start_of_this_item = offset;
911 
912       uint32_t offset_to_next = extractor.GetU32(&offset);
913 
914       offset += 4; // Skip over the 4 bytes of reserved space
915       addr_t queue = extractor.GetPointer(&offset);
916       uint64_t serialnum = extractor.GetU64(&offset);
917       uint32_t running_work_items_count = extractor.GetU32(&offset);
918       uint32_t pending_work_items_count = extractor.GetU32(&offset);
919 
920       // Read the first field of the variable length data
921       offset = start_of_this_item +
922                m_lib_backtrace_recording_info.queue_info_data_offset;
923       const char *queue_label = extractor.GetCStr(&offset);
924       if (queue_label == nullptr)
925         queue_label = "";
926 
927       offset_t start_of_next_item = start_of_this_item + offset_to_next;
928       offset = start_of_next_item;
929 
930       LLDB_LOGF(log,
931                 "SystemRuntimeMacOSX::PopulateQueuesUsingLibBTR added "
932                 "queue with dispatch_queue_t 0x%" PRIx64
933                 ", serial number 0x%" PRIx64
934                 ", running items %d, pending items %d, name '%s'",
935                 queue, serialnum, running_work_items_count,
936                 pending_work_items_count, queue_label);
937 
938       QueueSP queue_sp(
939           new Queue(m_process->shared_from_this(), serialnum, queue_label));
940       queue_sp->SetNumRunningWorkItems(running_work_items_count);
941       queue_sp->SetNumPendingWorkItems(pending_work_items_count);
942       queue_sp->SetLibdispatchQueueAddress(queue);
943       queue_sp->SetKind(GetQueueKind(queue));
944       queue_list.AddQueue(queue_sp);
945       queues_read++;
946     }
947   }
948 }
949 
950 SystemRuntimeMacOSX::ItemInfo SystemRuntimeMacOSX::ExtractItemInfoFromBuffer(
951     lldb_private::DataExtractor &extractor) {
952   ItemInfo item;
953 
954   offset_t offset = 0;
955 
956   item.item_that_enqueued_this = extractor.GetPointer(&offset);
957   item.function_or_block = extractor.GetPointer(&offset);
958   item.enqueuing_thread_id = extractor.GetU64(&offset);
959   item.enqueuing_queue_serialnum = extractor.GetU64(&offset);
960   item.target_queue_serialnum = extractor.GetU64(&offset);
961   item.enqueuing_callstack_frame_count = extractor.GetU32(&offset);
962   item.stop_id = extractor.GetU32(&offset);
963 
964   offset = m_lib_backtrace_recording_info.item_info_data_offset;
965 
966   for (uint32_t i = 0; i < item.enqueuing_callstack_frame_count; i++) {
967     item.enqueuing_callstack.push_back(extractor.GetPointer(&offset));
968   }
969   item.enqueuing_thread_label = extractor.GetCStr(&offset);
970   item.enqueuing_queue_label = extractor.GetCStr(&offset);
971   item.target_queue_label = extractor.GetCStr(&offset);
972 
973   return item;
974 }
975 
976 void SystemRuntimeMacOSX::Initialize() {
977   PluginManager::RegisterPlugin(GetPluginNameStatic(),
978                                 GetPluginDescriptionStatic(), CreateInstance);
979 }
980 
981 void SystemRuntimeMacOSX::Terminate() {
982   PluginManager::UnregisterPlugin(CreateInstance);
983 }
984 
985 lldb_private::ConstString SystemRuntimeMacOSX::GetPluginNameStatic() {
986   static ConstString g_name("systemruntime-macosx");
987   return g_name;
988 }
989 
990 const char *SystemRuntimeMacOSX::GetPluginDescriptionStatic() {
991   return "System runtime plugin for Mac OS X native libraries.";
992 }
993 
994 // PluginInterface protocol
995 lldb_private::ConstString SystemRuntimeMacOSX::GetPluginName() {
996   return GetPluginNameStatic();
997 }
998 
999 uint32_t SystemRuntimeMacOSX::GetPluginVersion() { return 1; }
1000