xref: /openbsd-src/gnu/llvm/lldb/source/Plugins/SystemRuntime/MacOSX/SystemRuntimeMacOSX.cpp (revision d2c5a4743fb945f45b034a3a830a96f7e1bc695d)
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         ClangASTContext::GetScratch(m_process->GetTarget());
416     if (m_dispatch_tsd_indexes_addr != LLDB_INVALID_ADDRESS) {
417       CompilerType uint16 =
418           ast_ctx->GetBuiltinTypeForEncodingAndBitSize(eEncodingUint, 16);
419       CompilerType dispatch_tsd_indexes_s = ast_ctx->CreateRecordType(
420           nullptr, lldb::eAccessPublic, "__lldb_dispatch_tsd_indexes_s",
421           clang::TTK_Struct, lldb::eLanguageTypeC);
422 
423       ClangASTContext::StartTagDeclarationDefinition(dispatch_tsd_indexes_s);
424       ClangASTContext::AddFieldToRecordType(dispatch_tsd_indexes_s,
425                                             "dti_version", uint16,
426                                             lldb::eAccessPublic, 0);
427       ClangASTContext::AddFieldToRecordType(dispatch_tsd_indexes_s,
428                                             "dti_queue_index", uint16,
429                                             lldb::eAccessPublic, 0);
430       ClangASTContext::AddFieldToRecordType(dispatch_tsd_indexes_s,
431                                             "dti_voucher_index", uint16,
432                                             lldb::eAccessPublic, 0);
433       ClangASTContext::AddFieldToRecordType(dispatch_tsd_indexes_s,
434                                             "dti_qos_class_index", uint16,
435                                             lldb::eAccessPublic, 0);
436       ClangASTContext::CompleteTagDeclarationDefinition(dispatch_tsd_indexes_s);
437 
438       ProcessStructReader struct_reader(m_process, m_dispatch_tsd_indexes_addr,
439                                         dispatch_tsd_indexes_s);
440 
441       m_libdispatch_tsd_indexes.dti_version =
442           struct_reader.GetField<uint16_t>(ConstString("dti_version"));
443       m_libdispatch_tsd_indexes.dti_queue_index =
444           struct_reader.GetField<uint16_t>(ConstString("dti_queue_index"));
445       m_libdispatch_tsd_indexes.dti_voucher_index =
446           struct_reader.GetField<uint16_t>(ConstString("dti_voucher_index"));
447       m_libdispatch_tsd_indexes.dti_qos_class_index =
448           struct_reader.GetField<uint16_t>(ConstString("dti_qos_class_index"));
449     }
450   }
451 }
452 
453 ThreadSP SystemRuntimeMacOSX::GetExtendedBacktraceThread(ThreadSP real_thread,
454                                                          ConstString type) {
455   ThreadSP originating_thread_sp;
456   if (BacktraceRecordingHeadersInitialized() && type == "libdispatch") {
457     Status error;
458 
459     // real_thread is either an actual, live thread (in which case we need to
460     // call into libBacktraceRecording to find its originator) or it is an
461     // extended backtrace itself, in which case we get the token from it and
462     // call into libBacktraceRecording to find the originator of that token.
463 
464     if (real_thread->GetExtendedBacktraceToken() != LLDB_INVALID_ADDRESS) {
465       originating_thread_sp = GetExtendedBacktraceFromItemRef(
466           real_thread->GetExtendedBacktraceToken());
467     } else {
468       ThreadSP cur_thread_sp(
469           m_process->GetThreadList().GetExpressionExecutionThread());
470       AppleGetThreadItemInfoHandler::GetThreadItemInfoReturnInfo ret =
471           m_get_thread_item_info_handler.GetThreadItemInfo(
472               *cur_thread_sp.get(), real_thread->GetID(), m_page_to_free,
473               m_page_to_free_size, error);
474       m_page_to_free = LLDB_INVALID_ADDRESS;
475       m_page_to_free_size = 0;
476       if (ret.item_buffer_ptr != 0 &&
477           ret.item_buffer_ptr != LLDB_INVALID_ADDRESS &&
478           ret.item_buffer_size > 0) {
479         DataBufferHeap data(ret.item_buffer_size, 0);
480         if (m_process->ReadMemory(ret.item_buffer_ptr, data.GetBytes(),
481                                   ret.item_buffer_size, error) &&
482             error.Success()) {
483           DataExtractor extractor(data.GetBytes(), data.GetByteSize(),
484                                   m_process->GetByteOrder(),
485                                   m_process->GetAddressByteSize());
486           ItemInfo item = ExtractItemInfoFromBuffer(extractor);
487           originating_thread_sp = std::make_shared<HistoryThread>(
488               *m_process, item.enqueuing_thread_id, item.enqueuing_callstack);
489           originating_thread_sp->SetExtendedBacktraceToken(
490               item.item_that_enqueued_this);
491           originating_thread_sp->SetQueueName(
492               item.enqueuing_queue_label.c_str());
493           originating_thread_sp->SetQueueID(item.enqueuing_queue_serialnum);
494           //                    originating_thread_sp->SetThreadName
495           //                    (item.enqueuing_thread_label.c_str());
496         }
497         m_page_to_free = ret.item_buffer_ptr;
498         m_page_to_free_size = ret.item_buffer_size;
499       }
500     }
501   }
502   return originating_thread_sp;
503 }
504 
505 ThreadSP
506 SystemRuntimeMacOSX::GetExtendedBacktraceFromItemRef(lldb::addr_t item_ref) {
507   ThreadSP return_thread_sp;
508 
509   AppleGetItemInfoHandler::GetItemInfoReturnInfo ret;
510   ThreadSP cur_thread_sp(
511       m_process->GetThreadList().GetExpressionExecutionThread());
512   Status error;
513   ret = m_get_item_info_handler.GetItemInfo(*cur_thread_sp.get(), item_ref,
514                                             m_page_to_free, m_page_to_free_size,
515                                             error);
516   m_page_to_free = LLDB_INVALID_ADDRESS;
517   m_page_to_free_size = 0;
518   if (ret.item_buffer_ptr != 0 && ret.item_buffer_ptr != LLDB_INVALID_ADDRESS &&
519       ret.item_buffer_size > 0) {
520     DataBufferHeap data(ret.item_buffer_size, 0);
521     if (m_process->ReadMemory(ret.item_buffer_ptr, data.GetBytes(),
522                               ret.item_buffer_size, error) &&
523         error.Success()) {
524       DataExtractor extractor(data.GetBytes(), data.GetByteSize(),
525                               m_process->GetByteOrder(),
526                               m_process->GetAddressByteSize());
527       ItemInfo item = ExtractItemInfoFromBuffer(extractor);
528       return_thread_sp = std::make_shared<HistoryThread>(
529           *m_process, item.enqueuing_thread_id, item.enqueuing_callstack);
530       return_thread_sp->SetExtendedBacktraceToken(item.item_that_enqueued_this);
531       return_thread_sp->SetQueueName(item.enqueuing_queue_label.c_str());
532       return_thread_sp->SetQueueID(item.enqueuing_queue_serialnum);
533       //            return_thread_sp->SetThreadName
534       //            (item.enqueuing_thread_label.c_str());
535 
536       m_page_to_free = ret.item_buffer_ptr;
537       m_page_to_free_size = ret.item_buffer_size;
538     }
539   }
540   return return_thread_sp;
541 }
542 
543 ThreadSP
544 SystemRuntimeMacOSX::GetExtendedBacktraceForQueueItem(QueueItemSP queue_item_sp,
545                                                       ConstString type) {
546   ThreadSP extended_thread_sp;
547   if (type != "libdispatch")
548     return extended_thread_sp;
549 
550   extended_thread_sp = std::make_shared<HistoryThread>(
551       *m_process, queue_item_sp->GetEnqueueingThreadID(),
552       queue_item_sp->GetEnqueueingBacktrace());
553   extended_thread_sp->SetExtendedBacktraceToken(
554       queue_item_sp->GetItemThatEnqueuedThis());
555   extended_thread_sp->SetQueueName(queue_item_sp->GetQueueLabel().c_str());
556   extended_thread_sp->SetQueueID(queue_item_sp->GetEnqueueingQueueID());
557   //    extended_thread_sp->SetThreadName
558   //    (queue_item_sp->GetThreadLabel().c_str());
559 
560   return extended_thread_sp;
561 }
562 
563 /* Returns true if we were able to get the version / offset information
564  * out of libBacktraceRecording.  false means we were unable to retrieve
565  * this; the queue_info_version field will be 0.
566  */
567 
568 bool SystemRuntimeMacOSX::BacktraceRecordingHeadersInitialized() {
569   if (m_lib_backtrace_recording_info.queue_info_version != 0)
570     return true;
571 
572   addr_t queue_info_version_address = LLDB_INVALID_ADDRESS;
573   addr_t queue_info_data_offset_address = LLDB_INVALID_ADDRESS;
574   addr_t item_info_version_address = LLDB_INVALID_ADDRESS;
575   addr_t item_info_data_offset_address = LLDB_INVALID_ADDRESS;
576   Target &target = m_process->GetTarget();
577 
578   static ConstString introspection_dispatch_queue_info_version(
579       "__introspection_dispatch_queue_info_version");
580   SymbolContextList sc_list;
581   m_process->GetTarget().GetImages().FindSymbolsWithNameAndType(
582       introspection_dispatch_queue_info_version, eSymbolTypeData, sc_list);
583   if (!sc_list.IsEmpty()) {
584     SymbolContext sc;
585     sc_list.GetContextAtIndex(0, sc);
586     AddressRange addr_range;
587     sc.GetAddressRange(eSymbolContextSymbol, 0, false, addr_range);
588     queue_info_version_address =
589         addr_range.GetBaseAddress().GetLoadAddress(&target);
590   }
591   sc_list.Clear();
592 
593   static ConstString introspection_dispatch_queue_info_data_offset(
594       "__introspection_dispatch_queue_info_data_offset");
595   m_process->GetTarget().GetImages().FindSymbolsWithNameAndType(
596       introspection_dispatch_queue_info_data_offset, eSymbolTypeData, sc_list);
597   if (!sc_list.IsEmpty()) {
598     SymbolContext sc;
599     sc_list.GetContextAtIndex(0, sc);
600     AddressRange addr_range;
601     sc.GetAddressRange(eSymbolContextSymbol, 0, false, addr_range);
602     queue_info_data_offset_address =
603         addr_range.GetBaseAddress().GetLoadAddress(&target);
604   }
605   sc_list.Clear();
606 
607   static ConstString introspection_dispatch_item_info_version(
608       "__introspection_dispatch_item_info_version");
609   m_process->GetTarget().GetImages().FindSymbolsWithNameAndType(
610       introspection_dispatch_item_info_version, eSymbolTypeData, sc_list);
611   if (!sc_list.IsEmpty()) {
612     SymbolContext sc;
613     sc_list.GetContextAtIndex(0, sc);
614     AddressRange addr_range;
615     sc.GetAddressRange(eSymbolContextSymbol, 0, false, addr_range);
616     item_info_version_address =
617         addr_range.GetBaseAddress().GetLoadAddress(&target);
618   }
619   sc_list.Clear();
620 
621   static ConstString introspection_dispatch_item_info_data_offset(
622       "__introspection_dispatch_item_info_data_offset");
623   m_process->GetTarget().GetImages().FindSymbolsWithNameAndType(
624       introspection_dispatch_item_info_data_offset, eSymbolTypeData, sc_list);
625   if (!sc_list.IsEmpty()) {
626     SymbolContext sc;
627     sc_list.GetContextAtIndex(0, sc);
628     AddressRange addr_range;
629     sc.GetAddressRange(eSymbolContextSymbol, 0, false, addr_range);
630     item_info_data_offset_address =
631         addr_range.GetBaseAddress().GetLoadAddress(&target);
632   }
633 
634   if (queue_info_version_address != LLDB_INVALID_ADDRESS &&
635       queue_info_data_offset_address != LLDB_INVALID_ADDRESS &&
636       item_info_version_address != LLDB_INVALID_ADDRESS &&
637       item_info_data_offset_address != LLDB_INVALID_ADDRESS) {
638     Status error;
639     m_lib_backtrace_recording_info.queue_info_version =
640         m_process->ReadUnsignedIntegerFromMemory(queue_info_version_address, 2,
641                                                  0, error);
642     if (error.Success()) {
643       m_lib_backtrace_recording_info.queue_info_data_offset =
644           m_process->ReadUnsignedIntegerFromMemory(
645               queue_info_data_offset_address, 2, 0, error);
646       if (error.Success()) {
647         m_lib_backtrace_recording_info.item_info_version =
648             m_process->ReadUnsignedIntegerFromMemory(item_info_version_address,
649                                                      2, 0, error);
650         if (error.Success()) {
651           m_lib_backtrace_recording_info.item_info_data_offset =
652               m_process->ReadUnsignedIntegerFromMemory(
653                   item_info_data_offset_address, 2, 0, error);
654           if (!error.Success()) {
655             m_lib_backtrace_recording_info.queue_info_version = 0;
656           }
657         } else {
658           m_lib_backtrace_recording_info.queue_info_version = 0;
659         }
660       } else {
661         m_lib_backtrace_recording_info.queue_info_version = 0;
662       }
663     }
664   }
665 
666   return m_lib_backtrace_recording_info.queue_info_version != 0;
667 }
668 
669 const std::vector<ConstString> &
670 SystemRuntimeMacOSX::GetExtendedBacktraceTypes() {
671   if (m_types.size() == 0) {
672     m_types.push_back(ConstString("libdispatch"));
673     // We could have pthread as another type in the future if we have a way of
674     // gathering that information & it's useful to distinguish between them.
675   }
676   return m_types;
677 }
678 
679 void SystemRuntimeMacOSX::PopulateQueueList(
680     lldb_private::QueueList &queue_list) {
681   if (BacktraceRecordingHeadersInitialized()) {
682     AppleGetQueuesHandler::GetQueuesReturnInfo queue_info_pointer;
683     ThreadSP cur_thread_sp(
684         m_process->GetThreadList().GetExpressionExecutionThread());
685     if (cur_thread_sp) {
686       Status error;
687       queue_info_pointer = m_get_queues_handler.GetCurrentQueues(
688           *cur_thread_sp.get(), m_page_to_free, m_page_to_free_size, error);
689       m_page_to_free = LLDB_INVALID_ADDRESS;
690       m_page_to_free_size = 0;
691       if (error.Success()) {
692 
693         if (queue_info_pointer.count > 0 &&
694             queue_info_pointer.queues_buffer_size > 0 &&
695             queue_info_pointer.queues_buffer_ptr != 0 &&
696             queue_info_pointer.queues_buffer_ptr != LLDB_INVALID_ADDRESS) {
697           PopulateQueuesUsingLibBTR(queue_info_pointer.queues_buffer_ptr,
698                                     queue_info_pointer.queues_buffer_size,
699                                     queue_info_pointer.count, queue_list);
700         }
701       }
702     }
703   }
704 
705   // We either didn't have libBacktraceRecording (and need to create the queues
706   // list based on threads) or we did get the queues list from
707   // libBacktraceRecording but some special queues may not be included in its
708   // information.  This is needed because libBacktraceRecording will only list
709   // queues with pending or running items by default - but the magic com.apple
710   // .main-thread queue on thread 1 is always around.
711 
712   for (ThreadSP thread_sp : m_process->Threads()) {
713     if (thread_sp->GetAssociatedWithLibdispatchQueue() != eLazyBoolNo) {
714       if (thread_sp->GetQueueID() != LLDB_INVALID_QUEUE_ID) {
715         if (queue_list.FindQueueByID(thread_sp->GetQueueID()).get() ==
716             nullptr) {
717           QueueSP queue_sp(new Queue(m_process->shared_from_this(),
718                                      thread_sp->GetQueueID(),
719                                      thread_sp->GetQueueName()));
720           if (thread_sp->ThreadHasQueueInformation()) {
721             queue_sp->SetKind(thread_sp->GetQueueKind());
722             queue_sp->SetLibdispatchQueueAddress(
723                 thread_sp->GetQueueLibdispatchQueueAddress());
724             queue_list.AddQueue(queue_sp);
725           } else {
726             queue_sp->SetKind(
727                 GetQueueKind(thread_sp->GetQueueLibdispatchQueueAddress()));
728             queue_sp->SetLibdispatchQueueAddress(
729                 thread_sp->GetQueueLibdispatchQueueAddress());
730             queue_list.AddQueue(queue_sp);
731           }
732         }
733       }
734     }
735   }
736 }
737 
738 // Returns either an array of introspection_dispatch_item_info_ref's for the
739 // pending items on a queue or an array introspection_dispatch_item_info_ref's
740 // and code addresses for the pending items on a queue.  The information about
741 // each of these pending items then needs to be fetched individually by passing
742 // the ref to libBacktraceRecording.
743 
744 SystemRuntimeMacOSX::PendingItemsForQueue
745 SystemRuntimeMacOSX::GetPendingItemRefsForQueue(lldb::addr_t queue) {
746   PendingItemsForQueue pending_item_refs;
747   AppleGetPendingItemsHandler::GetPendingItemsReturnInfo pending_items_pointer;
748   ThreadSP cur_thread_sp(
749       m_process->GetThreadList().GetExpressionExecutionThread());
750   if (cur_thread_sp) {
751     Status error;
752     pending_items_pointer = m_get_pending_items_handler.GetPendingItems(
753         *cur_thread_sp.get(), queue, m_page_to_free, m_page_to_free_size,
754         error);
755     m_page_to_free = LLDB_INVALID_ADDRESS;
756     m_page_to_free_size = 0;
757     if (error.Success()) {
758       if (pending_items_pointer.count > 0 &&
759           pending_items_pointer.items_buffer_size > 0 &&
760           pending_items_pointer.items_buffer_ptr != 0 &&
761           pending_items_pointer.items_buffer_ptr != LLDB_INVALID_ADDRESS) {
762         DataBufferHeap data(pending_items_pointer.items_buffer_size, 0);
763         if (m_process->ReadMemory(
764                 pending_items_pointer.items_buffer_ptr, data.GetBytes(),
765                 pending_items_pointer.items_buffer_size, error)) {
766           DataExtractor extractor(data.GetBytes(), data.GetByteSize(),
767                                   m_process->GetByteOrder(),
768                                   m_process->GetAddressByteSize());
769 
770           // We either have an array of
771           //    void* item_ref
772           // (old style) or we have a structure returned which looks like
773           //
774           // struct introspection_dispatch_pending_item_info_s {
775           //   void *item_ref;
776           //   void *function_or_block;
777           // };
778           //
779           // struct introspection_dispatch_pending_items_array_s {
780           //   uint32_t version;
781           //   uint32_t size_of_item_info;
782           //   introspection_dispatch_pending_item_info_s items[];
783           //   }
784 
785           offset_t offset = 0;
786           int i = 0;
787           uint32_t version = extractor.GetU32(&offset);
788           if (version == 1) {
789             pending_item_refs.new_style = true;
790             uint32_t item_size = extractor.GetU32(&offset);
791             uint32_t start_of_array_offset = offset;
792             while (offset < pending_items_pointer.items_buffer_size &&
793                    static_cast<size_t>(i) < pending_items_pointer.count) {
794               offset = start_of_array_offset + (i * item_size);
795               ItemRefAndCodeAddress item;
796               item.item_ref = extractor.GetPointer(&offset);
797               item.code_address = extractor.GetPointer(&offset);
798               pending_item_refs.item_refs_and_code_addresses.push_back(item);
799               i++;
800             }
801           } else {
802             offset = 0;
803             pending_item_refs.new_style = false;
804             while (offset < pending_items_pointer.items_buffer_size &&
805                    static_cast<size_t>(i) < pending_items_pointer.count) {
806               ItemRefAndCodeAddress item;
807               item.item_ref = extractor.GetPointer(&offset);
808               item.code_address = LLDB_INVALID_ADDRESS;
809               pending_item_refs.item_refs_and_code_addresses.push_back(item);
810               i++;
811             }
812           }
813         }
814         m_page_to_free = pending_items_pointer.items_buffer_ptr;
815         m_page_to_free_size = pending_items_pointer.items_buffer_size;
816       }
817     }
818   }
819   return pending_item_refs;
820 }
821 
822 void SystemRuntimeMacOSX::PopulatePendingItemsForQueue(Queue *queue) {
823   if (BacktraceRecordingHeadersInitialized()) {
824     PendingItemsForQueue pending_item_refs =
825         GetPendingItemRefsForQueue(queue->GetLibdispatchQueueAddress());
826     for (ItemRefAndCodeAddress pending_item :
827          pending_item_refs.item_refs_and_code_addresses) {
828       Address addr;
829       m_process->GetTarget().ResolveLoadAddress(pending_item.code_address,
830                                                 addr);
831       QueueItemSP queue_item_sp(new QueueItem(queue->shared_from_this(),
832                                               m_process->shared_from_this(),
833                                               pending_item.item_ref, addr));
834       queue->PushPendingQueueItem(queue_item_sp);
835     }
836   }
837 }
838 
839 void SystemRuntimeMacOSX::CompleteQueueItem(QueueItem *queue_item,
840                                             addr_t item_ref) {
841   AppleGetItemInfoHandler::GetItemInfoReturnInfo ret;
842 
843   ThreadSP cur_thread_sp(
844       m_process->GetThreadList().GetExpressionExecutionThread());
845   Status error;
846   ret = m_get_item_info_handler.GetItemInfo(*cur_thread_sp.get(), item_ref,
847                                             m_page_to_free, m_page_to_free_size,
848                                             error);
849   m_page_to_free = LLDB_INVALID_ADDRESS;
850   m_page_to_free_size = 0;
851   if (ret.item_buffer_ptr != 0 && ret.item_buffer_ptr != LLDB_INVALID_ADDRESS &&
852       ret.item_buffer_size > 0) {
853     DataBufferHeap data(ret.item_buffer_size, 0);
854     if (m_process->ReadMemory(ret.item_buffer_ptr, data.GetBytes(),
855                               ret.item_buffer_size, error) &&
856         error.Success()) {
857       DataExtractor extractor(data.GetBytes(), data.GetByteSize(),
858                               m_process->GetByteOrder(),
859                               m_process->GetAddressByteSize());
860       ItemInfo item = ExtractItemInfoFromBuffer(extractor);
861       queue_item->SetItemThatEnqueuedThis(item.item_that_enqueued_this);
862       queue_item->SetEnqueueingThreadID(item.enqueuing_thread_id);
863       queue_item->SetEnqueueingQueueID(item.enqueuing_queue_serialnum);
864       queue_item->SetStopID(item.stop_id);
865       queue_item->SetEnqueueingBacktrace(item.enqueuing_callstack);
866       queue_item->SetThreadLabel(item.enqueuing_thread_label);
867       queue_item->SetQueueLabel(item.enqueuing_queue_label);
868       queue_item->SetTargetQueueLabel(item.target_queue_label);
869     }
870     m_page_to_free = ret.item_buffer_ptr;
871     m_page_to_free_size = ret.item_buffer_size;
872   }
873 }
874 
875 void SystemRuntimeMacOSX::PopulateQueuesUsingLibBTR(
876     lldb::addr_t queues_buffer, uint64_t queues_buffer_size, uint64_t count,
877     lldb_private::QueueList &queue_list) {
878   Status error;
879   DataBufferHeap data(queues_buffer_size, 0);
880   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME));
881   if (m_process->ReadMemory(queues_buffer, data.GetBytes(), queues_buffer_size,
882                             error) == queues_buffer_size &&
883       error.Success()) {
884     // We've read the information out of inferior memory; free it on the next
885     // call we make
886     m_page_to_free = queues_buffer;
887     m_page_to_free_size = queues_buffer_size;
888 
889     DataExtractor extractor(data.GetBytes(), data.GetByteSize(),
890                             m_process->GetByteOrder(),
891                             m_process->GetAddressByteSize());
892     offset_t offset = 0;
893     uint64_t queues_read = 0;
894 
895     // The information about the queues is stored in this format (v1): typedef
896     // struct introspection_dispatch_queue_info_s {
897     //     uint32_t offset_to_next;
898     //     dispatch_queue_t queue;
899     //     uint64_t serialnum;     // queue's serialnum in the process, as
900     //     provided by libdispatch
901     //     uint32_t running_work_items_count;
902     //     uint32_t pending_work_items_count;
903     //
904     //     char data[];     // Starting here, we have variable-length data:
905     //     // char queue_label[];
906     // } introspection_dispatch_queue_info_s;
907 
908     while (queues_read < count && offset < queues_buffer_size) {
909       offset_t start_of_this_item = offset;
910 
911       uint32_t offset_to_next = extractor.GetU32(&offset);
912 
913       offset += 4; // Skip over the 4 bytes of reserved space
914       addr_t queue = extractor.GetPointer(&offset);
915       uint64_t serialnum = extractor.GetU64(&offset);
916       uint32_t running_work_items_count = extractor.GetU32(&offset);
917       uint32_t pending_work_items_count = extractor.GetU32(&offset);
918 
919       // Read the first field of the variable length data
920       offset = start_of_this_item +
921                m_lib_backtrace_recording_info.queue_info_data_offset;
922       const char *queue_label = extractor.GetCStr(&offset);
923       if (queue_label == nullptr)
924         queue_label = "";
925 
926       offset_t start_of_next_item = start_of_this_item + offset_to_next;
927       offset = start_of_next_item;
928 
929       LLDB_LOGF(log,
930                 "SystemRuntimeMacOSX::PopulateQueuesUsingLibBTR added "
931                 "queue with dispatch_queue_t 0x%" PRIx64
932                 ", serial number 0x%" PRIx64
933                 ", running items %d, pending items %d, name '%s'",
934                 queue, serialnum, running_work_items_count,
935                 pending_work_items_count, queue_label);
936 
937       QueueSP queue_sp(
938           new Queue(m_process->shared_from_this(), serialnum, queue_label));
939       queue_sp->SetNumRunningWorkItems(running_work_items_count);
940       queue_sp->SetNumPendingWorkItems(pending_work_items_count);
941       queue_sp->SetLibdispatchQueueAddress(queue);
942       queue_sp->SetKind(GetQueueKind(queue));
943       queue_list.AddQueue(queue_sp);
944       queues_read++;
945     }
946   }
947 }
948 
949 SystemRuntimeMacOSX::ItemInfo SystemRuntimeMacOSX::ExtractItemInfoFromBuffer(
950     lldb_private::DataExtractor &extractor) {
951   ItemInfo item;
952 
953   offset_t offset = 0;
954 
955   item.item_that_enqueued_this = extractor.GetPointer(&offset);
956   item.function_or_block = extractor.GetPointer(&offset);
957   item.enqueuing_thread_id = extractor.GetU64(&offset);
958   item.enqueuing_queue_serialnum = extractor.GetU64(&offset);
959   item.target_queue_serialnum = extractor.GetU64(&offset);
960   item.enqueuing_callstack_frame_count = extractor.GetU32(&offset);
961   item.stop_id = extractor.GetU32(&offset);
962 
963   offset = m_lib_backtrace_recording_info.item_info_data_offset;
964 
965   for (uint32_t i = 0; i < item.enqueuing_callstack_frame_count; i++) {
966     item.enqueuing_callstack.push_back(extractor.GetPointer(&offset));
967   }
968   item.enqueuing_thread_label = extractor.GetCStr(&offset);
969   item.enqueuing_queue_label = extractor.GetCStr(&offset);
970   item.target_queue_label = extractor.GetCStr(&offset);
971 
972   return item;
973 }
974 
975 void SystemRuntimeMacOSX::Initialize() {
976   PluginManager::RegisterPlugin(GetPluginNameStatic(),
977                                 GetPluginDescriptionStatic(), CreateInstance);
978 }
979 
980 void SystemRuntimeMacOSX::Terminate() {
981   PluginManager::UnregisterPlugin(CreateInstance);
982 }
983 
984 lldb_private::ConstString SystemRuntimeMacOSX::GetPluginNameStatic() {
985   static ConstString g_name("systemruntime-macosx");
986   return g_name;
987 }
988 
989 const char *SystemRuntimeMacOSX::GetPluginDescriptionStatic() {
990   return "System runtime plugin for Mac OS X native libraries.";
991 }
992 
993 // PluginInterface protocol
994 lldb_private::ConstString SystemRuntimeMacOSX::GetPluginName() {
995   return GetPluginNameStatic();
996 }
997 
998 uint32_t SystemRuntimeMacOSX::GetPluginVersion() { return 1; }
999