1 //===-- SystemRuntimeMacOSX.cpp ---------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 
11 #include "lldb/Breakpoint/StoppointCallbackContext.h"
12 #include "lldb/Core/Log.h"
13 #include "lldb/Core/Module.h"
14 #include "lldb/Core/ModuleSpec.h"
15 #include "lldb/Core/PluginManager.h"
16 #include "lldb/Core/DataExtractor.h"
17 #include "lldb/Core/DataBufferHeap.h"
18 #include "lldb/Core/Section.h"
19 #include "lldb/Core/StreamString.h"
20 #include "lldb/Expression/ClangFunction.h"
21 #include "lldb/Expression/ClangUtilityFunction.h"
22 #include "lldb/Host/FileSpec.h"
23 #include "lldb/Symbol/ClangASTContext.h"
24 #include "lldb/Symbol/ObjectFile.h"
25 #include "lldb/Symbol/SymbolContext.h"
26 #include "Plugins/Process/Utility/HistoryThread.h"
27 #include "lldb/Target/Queue.h"
28 #include "lldb/Target/QueueList.h"
29 #include "lldb/Target/Target.h"
30 #include "lldb/Target/Thread.h"
31 #include "lldb/Target/Process.h"
32 #include "lldb/Utility/ProcessStructReader.h"
33 
34 #include "SystemRuntimeMacOSX.h"
35 
36 using namespace lldb;
37 using namespace lldb_private;
38 
39 //----------------------------------------------------------------------
40 // Create an instance of this class. This function is filled into
41 // the plugin info class that gets handed out by the plugin factory and
42 // allows the lldb to instantiate an instance of this class.
43 //----------------------------------------------------------------------
44 SystemRuntime *
45 SystemRuntimeMacOSX::CreateInstance (Process* process)
46 {
47     bool create = false;
48     if (!create)
49     {
50         create = true;
51         Module* exe_module = process->GetTarget().GetExecutableModulePointer();
52         if (exe_module)
53         {
54             ObjectFile *object_file = exe_module->GetObjectFile();
55             if (object_file)
56             {
57                 create = (object_file->GetStrata() == ObjectFile::eStrataUser);
58             }
59         }
60 
61         if (create)
62         {
63             const llvm::Triple &triple_ref = process->GetTarget().GetArchitecture().GetTriple();
64             switch (triple_ref.getOS())
65             {
66                 case llvm::Triple::Darwin:
67                 case llvm::Triple::MacOSX:
68                 case llvm::Triple::IOS:
69                     create = triple_ref.getVendor() == llvm::Triple::Apple;
70                     break;
71                 default:
72                     create = false;
73                     break;
74             }
75         }
76     }
77 
78     if (create)
79         return new SystemRuntimeMacOSX (process);
80     return NULL;
81 }
82 
83 //----------------------------------------------------------------------
84 // Constructor
85 //----------------------------------------------------------------------
86 SystemRuntimeMacOSX::SystemRuntimeMacOSX (Process* process) :
87     SystemRuntime(process),
88     m_break_id(LLDB_INVALID_BREAK_ID),
89     m_mutex(Mutex::eMutexTypeRecursive),
90     m_get_queues_handler(process),
91     m_get_pending_items_handler(process),
92     m_get_item_info_handler(process),
93     m_get_thread_item_info_handler(process),
94     m_page_to_free(LLDB_INVALID_ADDRESS),
95     m_page_to_free_size(0),
96     m_lib_backtrace_recording_info(),
97     m_dispatch_queue_offsets_addr (LLDB_INVALID_ADDRESS),
98     m_libdispatch_offsets(),
99     m_libpthread_layout_offsets_addr (LLDB_INVALID_ADDRESS),
100     m_libpthread_offsets(),
101     m_dispatch_tsd_indexes_addr (LLDB_INVALID_ADDRESS),
102     m_libdispatch_tsd_indexes(),
103     m_dispatch_voucher_offsets_addr (LLDB_INVALID_ADDRESS),
104     m_libdispatch_voucher_offsets()
105 {
106 }
107 
108 //----------------------------------------------------------------------
109 // Destructor
110 //----------------------------------------------------------------------
111 SystemRuntimeMacOSX::~SystemRuntimeMacOSX()
112 {
113     Clear (true);
114 }
115 
116 void
117 SystemRuntimeMacOSX::Detach ()
118 {
119         m_get_queues_handler.Detach();
120         m_get_pending_items_handler.Detach();
121         m_get_item_info_handler.Detach();
122         m_get_thread_item_info_handler.Detach();
123 }
124 
125 //----------------------------------------------------------------------
126 // Clear out the state of this class.
127 //----------------------------------------------------------------------
128 void
129 SystemRuntimeMacOSX::Clear (bool clear_process)
130 {
131     Mutex::Locker locker(m_mutex);
132 
133     if (m_process->IsAlive() && LLDB_BREAK_ID_IS_VALID(m_break_id))
134         m_process->ClearBreakpointSiteByID(m_break_id);
135 
136     if (clear_process)
137         m_process = NULL;
138     m_break_id = LLDB_INVALID_BREAK_ID;
139 }
140 
141 
142 std::string
143 SystemRuntimeMacOSX::GetQueueNameFromThreadQAddress (addr_t dispatch_qaddr)
144 {
145     std::string dispatch_queue_name;
146     if (dispatch_qaddr == LLDB_INVALID_ADDRESS || dispatch_qaddr == 0)
147         return "";
148 
149     ReadLibdispatchOffsets ();
150     if (m_libdispatch_offsets.IsValid ())
151     {
152         // dispatch_qaddr is from a thread_info(THREAD_IDENTIFIER_INFO) call for a thread -
153         // deref it to get the address of the dispatch_queue_t structure for this thread's
154         // queue.
155         Error error;
156         addr_t dispatch_queue_addr = m_process->ReadPointerFromMemory (dispatch_qaddr, error);
157         if (error.Success())
158         {
159             if (m_libdispatch_offsets.dqo_version >= 4)
160             {
161                 // libdispatch versions 4+, pointer to dispatch name is in the
162                 // queue structure.
163                 addr_t pointer_to_label_address = dispatch_queue_addr + m_libdispatch_offsets.dqo_label;
164                 addr_t label_addr = m_process->ReadPointerFromMemory (pointer_to_label_address, error);
165                 if (error.Success())
166                 {
167                     m_process->ReadCStringFromMemory (label_addr, dispatch_queue_name, error);
168                 }
169             }
170             else
171             {
172                 // libdispatch versions 1-3, dispatch name is a fixed width char array
173                 // in the queue structure.
174                 addr_t label_addr = dispatch_queue_addr + m_libdispatch_offsets.dqo_label;
175                 dispatch_queue_name.resize (m_libdispatch_offsets.dqo_label_size, '\0');
176                 size_t bytes_read = m_process->ReadMemory (label_addr, &dispatch_queue_name[0], m_libdispatch_offsets.dqo_label_size, error);
177                 if (bytes_read < m_libdispatch_offsets.dqo_label_size)
178                     dispatch_queue_name.erase (bytes_read);
179             }
180         }
181     }
182     return dispatch_queue_name;
183 }
184 
185 lldb::addr_t
186 SystemRuntimeMacOSX::GetLibdispatchQueueAddressFromThreadQAddress (addr_t dispatch_qaddr)
187 {
188     addr_t libdispatch_queue_t_address = LLDB_INVALID_ADDRESS;
189     Error error;
190     libdispatch_queue_t_address = m_process->ReadPointerFromMemory (dispatch_qaddr, error);
191     if (!error.Success())
192     {
193         libdispatch_queue_t_address = LLDB_INVALID_ADDRESS;
194     }
195     return libdispatch_queue_t_address;
196 }
197 
198 lldb::QueueKind
199 SystemRuntimeMacOSX::GetQueueKind (addr_t dispatch_queue_addr)
200 {
201     if (dispatch_queue_addr == LLDB_INVALID_ADDRESS || dispatch_queue_addr == 0)
202       return eQueueKindUnknown;
203 
204     QueueKind kind = eQueueKindUnknown;
205     ReadLibdispatchOffsets ();
206     if (m_libdispatch_offsets.IsValid () && m_libdispatch_offsets.dqo_version >= 4)
207     {
208         Error error;
209         uint64_t width = m_process->ReadUnsignedIntegerFromMemory (dispatch_queue_addr + m_libdispatch_offsets.dqo_width, m_libdispatch_offsets.dqo_width_size, 0, error);
210         if (error.Success())
211         {
212             if (width == 1)
213             {
214                 kind = eQueueKindSerial;
215             }
216             if (width > 1)
217             {
218                 kind = eQueueKindConcurrent;
219             }
220         }
221     }
222     return kind;
223 }
224 
225 void
226 SystemRuntimeMacOSX::AddThreadExtendedInfoPacketHints (lldb_private::StructuredData::ObjectSP dict_sp)
227 {
228     StructuredData::Dictionary *dict = dict_sp->GetAsDictionary();
229     if (dict)
230     {
231         ReadLibpthreadOffsets();
232         if (m_libpthread_offsets.IsValid())
233         {
234             dict->AddIntegerItem ("plo_pthread_tsd_base_offset", m_libpthread_offsets.plo_pthread_tsd_base_offset);
235             dict->AddIntegerItem ("plo_pthread_tsd_base_address_offset", m_libpthread_offsets.plo_pthread_tsd_base_address_offset);
236             dict->AddIntegerItem ("plo_pthread_tsd_entry_size", m_libpthread_offsets.plo_pthread_tsd_entry_size);
237         }
238 
239         ReadLibdispatchTSDIndexes ();
240         if (m_libdispatch_tsd_indexes.IsValid())
241         {
242             dict->AddIntegerItem ("dti_queue_index", m_libdispatch_tsd_indexes.dti_queue_index);
243             dict->AddIntegerItem ("dti_voucher_index", m_libdispatch_tsd_indexes.dti_voucher_index);
244             dict->AddIntegerItem ("dti_qos_class_index", m_libdispatch_tsd_indexes.dti_qos_class_index);
245         }
246     }
247 }
248 
249 bool
250 SystemRuntimeMacOSX::SafeToCallFunctionsOnThisThread (ThreadSP thread_sp)
251 {
252     if (thread_sp && thread_sp->GetStackFrameCount() > 0 && thread_sp->GetFrameWithConcreteFrameIndex(0))
253     {
254         const SymbolContext sym_ctx (thread_sp->GetFrameWithConcreteFrameIndex(0)->GetSymbolContext (eSymbolContextSymbol));
255         static ConstString g_select_symbol ("__select");
256         if (sym_ctx.GetFunctionName() == g_select_symbol)
257         {
258             return false;
259         }
260     }
261     return true;
262 }
263 
264 lldb::queue_id_t
265 SystemRuntimeMacOSX::GetQueueIDFromThreadQAddress (lldb::addr_t dispatch_qaddr)
266 {
267     queue_id_t queue_id = LLDB_INVALID_QUEUE_ID;
268 
269     if (dispatch_qaddr == LLDB_INVALID_ADDRESS || dispatch_qaddr == 0)
270         return queue_id;
271 
272     ReadLibdispatchOffsets ();
273     if (m_libdispatch_offsets.IsValid ())
274     {
275         // dispatch_qaddr is from a thread_info(THREAD_IDENTIFIER_INFO) call for a thread -
276         // deref it to get the address of the dispatch_queue_t structure for this thread's
277         // queue.
278         Error error;
279         uint64_t dispatch_queue_addr = m_process->ReadPointerFromMemory (dispatch_qaddr, error);
280         if (error.Success())
281         {
282             addr_t serialnum_address = dispatch_queue_addr + m_libdispatch_offsets.dqo_serialnum;
283             queue_id_t serialnum = m_process->ReadUnsignedIntegerFromMemory (serialnum_address, m_libdispatch_offsets.dqo_serialnum_size, LLDB_INVALID_QUEUE_ID, error);
284             if (error.Success())
285             {
286                 queue_id = serialnum;
287             }
288         }
289     }
290 
291     return queue_id;
292 }
293 
294 
295 void
296 SystemRuntimeMacOSX::ReadLibdispatchOffsetsAddress ()
297 {
298     if (m_dispatch_queue_offsets_addr != LLDB_INVALID_ADDRESS)
299         return;
300 
301     static ConstString g_dispatch_queue_offsets_symbol_name ("dispatch_queue_offsets");
302     const Symbol *dispatch_queue_offsets_symbol = NULL;
303 
304     // libdispatch symbols were in libSystem.B.dylib up through Mac OS X 10.6 ("Snow Leopard")
305     ModuleSpec libSystem_module_spec (FileSpec("libSystem.B.dylib", false));
306     ModuleSP module_sp(m_process->GetTarget().GetImages().FindFirstModule (libSystem_module_spec));
307     if (module_sp)
308         dispatch_queue_offsets_symbol = module_sp->FindFirstSymbolWithNameAndType (g_dispatch_queue_offsets_symbol_name, eSymbolTypeData);
309 
310     // libdispatch symbols are in their own dylib as of Mac OS X 10.7 ("Lion") and later
311     if (dispatch_queue_offsets_symbol == NULL)
312     {
313         ModuleSpec libdispatch_module_spec (FileSpec("libdispatch.dylib", false));
314         module_sp = m_process->GetTarget().GetImages().FindFirstModule (libdispatch_module_spec);
315         if (module_sp)
316             dispatch_queue_offsets_symbol = module_sp->FindFirstSymbolWithNameAndType (g_dispatch_queue_offsets_symbol_name, eSymbolTypeData);
317     }
318     if (dispatch_queue_offsets_symbol)
319         m_dispatch_queue_offsets_addr = dispatch_queue_offsets_symbol->GetLoadAddress(&m_process->GetTarget());
320 }
321 
322 void
323 SystemRuntimeMacOSX::ReadLibdispatchOffsets ()
324 {
325     if (m_libdispatch_offsets.IsValid())
326         return;
327 
328     ReadLibdispatchOffsetsAddress ();
329 
330     uint8_t memory_buffer[sizeof (struct LibdispatchOffsets)];
331     DataExtractor data (memory_buffer,
332                         sizeof(memory_buffer),
333                         m_process->GetByteOrder(),
334                         m_process->GetAddressByteSize());
335 
336     Error error;
337     if (m_process->ReadMemory (m_dispatch_queue_offsets_addr, memory_buffer, sizeof(memory_buffer), error) == sizeof(memory_buffer))
338     {
339         lldb::offset_t data_offset = 0;
340 
341         // The struct LibdispatchOffsets is a series of uint16_t's - extract them all
342         // in one big go.
343         data.GetU16 (&data_offset, &m_libdispatch_offsets.dqo_version, sizeof (struct LibdispatchOffsets) / sizeof (uint16_t));
344     }
345 }
346 
347 void
348 SystemRuntimeMacOSX::ReadLibpthreadOffsetsAddress ()
349 {
350     if (m_libpthread_layout_offsets_addr != LLDB_INVALID_ADDRESS)
351         return;
352 
353     static ConstString g_libpthread_layout_offsets_symbol_name ("pthread_layout_offsets");
354     const Symbol *libpthread_layout_offsets_symbol = NULL;
355 
356     ModuleSpec libpthread_module_spec (FileSpec("libsystem_pthread.dylib", false));
357     ModuleSP module_sp (m_process->GetTarget().GetImages().FindFirstModule (libpthread_module_spec));
358     if (module_sp)
359     {
360         libpthread_layout_offsets_symbol = module_sp->FindFirstSymbolWithNameAndType
361                                                            (g_libpthread_layout_offsets_symbol_name, eSymbolTypeData);
362         if (libpthread_layout_offsets_symbol)
363         {
364             m_libpthread_layout_offsets_addr = libpthread_layout_offsets_symbol->GetLoadAddress(&m_process->GetTarget());
365         }
366     }
367 }
368 
369 void
370 SystemRuntimeMacOSX::ReadLibpthreadOffsets ()
371 {
372     if (m_libpthread_offsets.IsValid())
373         return;
374 
375     ReadLibpthreadOffsetsAddress ();
376 
377     if (m_libpthread_layout_offsets_addr != LLDB_INVALID_ADDRESS)
378     {
379         uint8_t memory_buffer[sizeof (struct LibpthreadOffsets)];
380         DataExtractor data (memory_buffer,
381                             sizeof(memory_buffer),
382                             m_process->GetByteOrder(),
383                             m_process->GetAddressByteSize());
384         Error error;
385         if (m_process->ReadMemory (m_libpthread_layout_offsets_addr, memory_buffer, sizeof(memory_buffer), error) == sizeof(memory_buffer))
386         {
387             lldb::offset_t data_offset = 0;
388 
389             // The struct LibpthreadOffsets is a series of uint16_t's - extract them all
390             // in one big go.
391             data.GetU16 (&data_offset, &m_libpthread_offsets.plo_version, sizeof (struct LibpthreadOffsets) / sizeof (uint16_t));
392         }
393     }
394 }
395 
396 void
397 SystemRuntimeMacOSX::ReadLibdispatchTSDIndexesAddress ()
398 {
399     if (m_dispatch_tsd_indexes_addr != LLDB_INVALID_ADDRESS)
400         return;
401 
402     static ConstString g_libdispatch_tsd_indexes_symbol_name ("dispatch_tsd_indexes");
403     const Symbol *libdispatch_tsd_indexes_symbol = NULL;
404 
405     ModuleSpec libpthread_module_spec (FileSpec("libdispatch.dylib", false));
406     ModuleSP module_sp (m_process->GetTarget().GetImages().FindFirstModule (libpthread_module_spec));
407     if (module_sp)
408     {
409         libdispatch_tsd_indexes_symbol = module_sp->FindFirstSymbolWithNameAndType
410                                                            (g_libdispatch_tsd_indexes_symbol_name, eSymbolTypeData);
411         if (libdispatch_tsd_indexes_symbol)
412         {
413             m_dispatch_tsd_indexes_addr = libdispatch_tsd_indexes_symbol->GetLoadAddress(&m_process->GetTarget());
414         }
415     }
416 }
417 
418 void
419 SystemRuntimeMacOSX::ReadLibdispatchTSDIndexes ()
420 {
421     if (m_libdispatch_tsd_indexes.IsValid())
422         return;
423 
424     ReadLibdispatchTSDIndexesAddress ();
425 
426     if (m_dispatch_tsd_indexes_addr != LLDB_INVALID_ADDRESS)
427     {
428 
429         // We don't need to check the version number right now, it will be at least 2, but
430         // keep this code around to fetch just the version # for the future where we need
431         // to fetch alternate versions of the struct.
432 # if 0
433         uint16_t dti_version = 2;
434         Address dti_struct_addr;
435         if (m_process->GetTarget().ResolveLoadAddress (m_dispatch_tsd_indexes_addr, dti_struct_addr))
436         {
437             Error error;
438             uint16_t version = m_process->GetTarget().ReadUnsignedIntegerFromMemory (dti_struct_addr, false, 2, UINT16_MAX, error);
439             if (error.Success() && dti_version != UINT16_MAX)
440             {
441                 dti_version = version;
442             }
443         }
444 #endif
445 
446         ClangASTContext *ast_ctx = m_process->GetTarget().GetScratchClangASTContext();
447         if (ast_ctx->getASTContext() && m_dispatch_tsd_indexes_addr != LLDB_INVALID_ADDRESS)
448         {
449             ClangASTType uint16 = ast_ctx->GetIntTypeFromBitSize(16, false);
450             ClangASTType dispatch_tsd_indexes_s = ast_ctx->CreateRecordType(nullptr, lldb::eAccessPublic, "__lldb_dispatch_tsd_indexes_s", clang::TTK_Struct, lldb::eLanguageTypeC);
451             dispatch_tsd_indexes_s.StartTagDeclarationDefinition();
452             dispatch_tsd_indexes_s.AddFieldToRecordType ("dti_version", uint16, lldb::eAccessPublic, 0);
453             dispatch_tsd_indexes_s.AddFieldToRecordType ("dti_queue_index", uint16, lldb::eAccessPublic, 0);
454             dispatch_tsd_indexes_s.AddFieldToRecordType ("dti_voucher_index", uint16, lldb::eAccessPublic, 0);
455             dispatch_tsd_indexes_s.AddFieldToRecordType ("dti_qos_class_index", uint16, lldb::eAccessPublic, 0);
456             dispatch_tsd_indexes_s.CompleteTagDeclarationDefinition();
457 
458             ProcessStructReader struct_reader (m_process, m_dispatch_tsd_indexes_addr, dispatch_tsd_indexes_s);
459 
460             m_libdispatch_tsd_indexes.dti_version = struct_reader.GetField<uint16_t>(ConstString("dti_version"));
461             m_libdispatch_tsd_indexes.dti_queue_index = struct_reader.GetField<uint16_t>(ConstString("dti_queue_index"));
462             m_libdispatch_tsd_indexes.dti_voucher_index = struct_reader.GetField<uint16_t>(ConstString("dti_voucher_index"));
463             m_libdispatch_tsd_indexes.dti_qos_class_index = struct_reader.GetField<uint16_t>(ConstString("dti_qos_class_index"));
464         }
465     }
466 }
467 
468 
469 ThreadSP
470 SystemRuntimeMacOSX::GetExtendedBacktraceThread (ThreadSP real_thread, ConstString type)
471 {
472     ThreadSP originating_thread_sp;
473     if (BacktraceRecordingHeadersInitialized() && type == ConstString ("libdispatch"))
474     {
475         Error error;
476 
477         // real_thread is either an actual, live thread (in which case we need to call into
478         // libBacktraceRecording to find its originator) or it is an extended backtrace itself,
479         // in which case we get the token from it and call into libBacktraceRecording to find
480         // the originator of that token.
481 
482         if (real_thread->GetExtendedBacktraceToken() != LLDB_INVALID_ADDRESS)
483         {
484             originating_thread_sp = GetExtendedBacktraceFromItemRef (real_thread->GetExtendedBacktraceToken());
485         }
486         else
487         {
488             ThreadSP cur_thread_sp (m_process->GetThreadList().GetSelectedThread());
489             AppleGetThreadItemInfoHandler::GetThreadItemInfoReturnInfo ret = m_get_thread_item_info_handler.GetThreadItemInfo (*cur_thread_sp.get(), real_thread->GetID(), m_page_to_free, m_page_to_free_size, error);
490             m_page_to_free = LLDB_INVALID_ADDRESS;
491             m_page_to_free_size = 0;
492             if (ret.item_buffer_ptr != 0 &&  ret.item_buffer_ptr != LLDB_INVALID_ADDRESS && ret.item_buffer_size > 0)
493             {
494                 DataBufferHeap data (ret.item_buffer_size, 0);
495                 if (m_process->ReadMemory (ret.item_buffer_ptr, data.GetBytes(), ret.item_buffer_size, error) && error.Success())
496                 {
497                     DataExtractor extractor (data.GetBytes(), data.GetByteSize(), m_process->GetByteOrder(), m_process->GetAddressByteSize());
498                     ItemInfo item = ExtractItemInfoFromBuffer (extractor);
499                     bool stop_id_is_valid = true;
500                     if (item.stop_id == 0)
501                         stop_id_is_valid = false;
502                     originating_thread_sp.reset (new HistoryThread (*m_process,
503                                                                     item.enqueuing_thread_id,
504                                                                     item.enqueuing_callstack,
505                                                                     item.stop_id,
506                                                                     stop_id_is_valid));
507                     originating_thread_sp->SetExtendedBacktraceToken (item.item_that_enqueued_this);
508                     originating_thread_sp->SetQueueName (item.enqueuing_queue_label.c_str());
509                     originating_thread_sp->SetQueueID (item.enqueuing_queue_serialnum);
510 //                    originating_thread_sp->SetThreadName (item.enqueuing_thread_label.c_str());
511                 }
512                 m_page_to_free = ret.item_buffer_ptr;
513                 m_page_to_free_size = ret.item_buffer_size;
514             }
515         }
516     }
517     return originating_thread_sp;
518 }
519 
520 ThreadSP
521 SystemRuntimeMacOSX::GetExtendedBacktraceFromItemRef (lldb::addr_t item_ref)
522 {
523     ThreadSP return_thread_sp;
524 
525     AppleGetItemInfoHandler::GetItemInfoReturnInfo ret;
526     ThreadSP cur_thread_sp (m_process->GetThreadList().GetSelectedThread());
527     Error error;
528     ret = m_get_item_info_handler.GetItemInfo (*cur_thread_sp.get(), item_ref, m_page_to_free, m_page_to_free_size, error);
529     m_page_to_free = LLDB_INVALID_ADDRESS;
530     m_page_to_free_size = 0;
531     if (ret.item_buffer_ptr != 0 &&  ret.item_buffer_ptr != LLDB_INVALID_ADDRESS && ret.item_buffer_size > 0)
532     {
533         DataBufferHeap data (ret.item_buffer_size, 0);
534         if (m_process->ReadMemory (ret.item_buffer_ptr, data.GetBytes(), ret.item_buffer_size, error) && error.Success())
535         {
536             DataExtractor extractor (data.GetBytes(), data.GetByteSize(), m_process->GetByteOrder(), m_process->GetAddressByteSize());
537             ItemInfo item = ExtractItemInfoFromBuffer (extractor);
538             bool stop_id_is_valid = true;
539             if (item.stop_id == 0)
540                 stop_id_is_valid = false;
541             return_thread_sp.reset (new HistoryThread (*m_process,
542                                                             item.enqueuing_thread_id,
543                                                             item.enqueuing_callstack,
544                                                             item.stop_id,
545                                                             stop_id_is_valid));
546             return_thread_sp->SetExtendedBacktraceToken (item.item_that_enqueued_this);
547             return_thread_sp->SetQueueName (item.enqueuing_queue_label.c_str());
548             return_thread_sp->SetQueueID (item.enqueuing_queue_serialnum);
549 //            return_thread_sp->SetThreadName (item.enqueuing_thread_label.c_str());
550 
551             m_page_to_free = ret.item_buffer_ptr;
552             m_page_to_free_size = ret.item_buffer_size;
553         }
554     }
555     return return_thread_sp;
556 }
557 
558 ThreadSP
559 SystemRuntimeMacOSX::GetExtendedBacktraceForQueueItem (QueueItemSP queue_item_sp, ConstString type)
560 {
561     ThreadSP extended_thread_sp;
562     if (type != ConstString("libdispatch"))
563         return extended_thread_sp;
564 
565     bool stop_id_is_valid = true;
566     if (queue_item_sp->GetStopID() == 0)
567         stop_id_is_valid = false;
568 
569     extended_thread_sp.reset (new HistoryThread (*m_process,
570                                                  queue_item_sp->GetEnqueueingThreadID(),
571                                                  queue_item_sp->GetEnqueueingBacktrace(),
572                                                  queue_item_sp->GetStopID(),
573                                                  stop_id_is_valid));
574     extended_thread_sp->SetExtendedBacktraceToken (queue_item_sp->GetItemThatEnqueuedThis());
575     extended_thread_sp->SetQueueName (queue_item_sp->GetQueueLabel().c_str());
576     extended_thread_sp->SetQueueID (queue_item_sp->GetEnqueueingQueueID());
577 //    extended_thread_sp->SetThreadName (queue_item_sp->GetThreadLabel().c_str());
578 
579     return extended_thread_sp;
580 }
581 
582 /* Returns true if we were able to get the version / offset information
583  * out of libBacktraceRecording.  false means we were unable to retrieve
584  * this; the queue_info_version field will be 0.
585  */
586 
587 bool
588 SystemRuntimeMacOSX::BacktraceRecordingHeadersInitialized ()
589 {
590     if (m_lib_backtrace_recording_info.queue_info_version != 0)
591         return true;
592 
593     addr_t queue_info_version_address = LLDB_INVALID_ADDRESS;
594     addr_t queue_info_data_offset_address = LLDB_INVALID_ADDRESS;
595     addr_t item_info_version_address = LLDB_INVALID_ADDRESS;
596     addr_t item_info_data_offset_address = LLDB_INVALID_ADDRESS;
597     Target &target = m_process->GetTarget();
598 
599 
600     static ConstString introspection_dispatch_queue_info_version ("__introspection_dispatch_queue_info_version");
601     SymbolContextList sc_list;
602     if (m_process->GetTarget().GetImages().FindSymbolsWithNameAndType (introspection_dispatch_queue_info_version, eSymbolTypeData, sc_list) > 0)
603     {
604         SymbolContext sc;
605         sc_list.GetContextAtIndex (0, sc);
606         AddressRange addr_range;
607         sc.GetAddressRange (eSymbolContextSymbol, 0, false, addr_range);
608         queue_info_version_address = addr_range.GetBaseAddress().GetLoadAddress(&target);
609     }
610     sc_list.Clear();
611 
612     static ConstString introspection_dispatch_queue_info_data_offset ("__introspection_dispatch_queue_info_data_offset");
613     if (m_process->GetTarget().GetImages().FindSymbolsWithNameAndType (introspection_dispatch_queue_info_data_offset, eSymbolTypeData, sc_list) > 0)
614     {
615         SymbolContext sc;
616         sc_list.GetContextAtIndex (0, sc);
617         AddressRange addr_range;
618         sc.GetAddressRange (eSymbolContextSymbol, 0, false, addr_range);
619         queue_info_data_offset_address = addr_range.GetBaseAddress().GetLoadAddress(&target);
620     }
621     sc_list.Clear();
622 
623     static ConstString introspection_dispatch_item_info_version ("__introspection_dispatch_item_info_version");
624     if (m_process->GetTarget().GetImages().FindSymbolsWithNameAndType (introspection_dispatch_item_info_version, eSymbolTypeData, sc_list) > 0)
625     {
626         SymbolContext sc;
627         sc_list.GetContextAtIndex (0, sc);
628         AddressRange addr_range;
629         sc.GetAddressRange (eSymbolContextSymbol, 0, false, addr_range);
630         item_info_version_address = addr_range.GetBaseAddress().GetLoadAddress(&target);
631     }
632     sc_list.Clear();
633 
634     static ConstString introspection_dispatch_item_info_data_offset ("__introspection_dispatch_item_info_data_offset");
635     if (m_process->GetTarget().GetImages().FindSymbolsWithNameAndType (introspection_dispatch_item_info_data_offset, eSymbolTypeData, sc_list) > 0)
636     {
637         SymbolContext sc;
638         sc_list.GetContextAtIndex (0, sc);
639         AddressRange addr_range;
640         sc.GetAddressRange (eSymbolContextSymbol, 0, false, addr_range);
641         item_info_data_offset_address = addr_range.GetBaseAddress().GetLoadAddress(&target);
642     }
643 
644     if (queue_info_version_address != LLDB_INVALID_ADDRESS
645         && queue_info_data_offset_address != LLDB_INVALID_ADDRESS
646         && item_info_version_address != LLDB_INVALID_ADDRESS
647         && item_info_data_offset_address != LLDB_INVALID_ADDRESS)
648     {
649         Error error;
650         m_lib_backtrace_recording_info.queue_info_version = m_process->ReadUnsignedIntegerFromMemory (queue_info_version_address, 2, 0, error);
651         if (error.Success())
652         {
653             m_lib_backtrace_recording_info.queue_info_data_offset = m_process->ReadUnsignedIntegerFromMemory (queue_info_data_offset_address, 2, 0, error);
654             if (error.Success())
655             {
656                 m_lib_backtrace_recording_info.item_info_version = m_process->ReadUnsignedIntegerFromMemory (item_info_version_address, 2, 0, error);
657                 if (error.Success())
658                 {
659                     m_lib_backtrace_recording_info.item_info_data_offset = m_process->ReadUnsignedIntegerFromMemory (item_info_data_offset_address, 2, 0, error);
660                     if (!error.Success())
661                     {
662                         m_lib_backtrace_recording_info.queue_info_version = 0;
663                     }
664                 }
665                 else
666                 {
667                     m_lib_backtrace_recording_info.queue_info_version = 0;
668                 }
669             }
670             else
671             {
672                 m_lib_backtrace_recording_info.queue_info_version = 0;
673             }
674         }
675     }
676 
677     return m_lib_backtrace_recording_info.queue_info_version != 0;
678 }
679 
680 const std::vector<ConstString> &
681 SystemRuntimeMacOSX::GetExtendedBacktraceTypes ()
682 {
683     if (m_types.size () == 0)
684     {
685         m_types.push_back(ConstString("libdispatch"));
686         // We could have pthread as another type in the future if we have a way of
687         // gathering that information & it's useful to distinguish between them.
688     }
689     return m_types;
690 }
691 
692 void
693 SystemRuntimeMacOSX::PopulateQueueList (lldb_private::QueueList &queue_list)
694 {
695     if (BacktraceRecordingHeadersInitialized())
696     {
697         AppleGetQueuesHandler::GetQueuesReturnInfo queue_info_pointer;
698         ThreadSP cur_thread_sp (m_process->GetThreadList().GetSelectedThread());
699         if (cur_thread_sp)
700         {
701             Error error;
702             queue_info_pointer = m_get_queues_handler.GetCurrentQueues (*cur_thread_sp.get(), m_page_to_free, m_page_to_free_size, error);
703             m_page_to_free = LLDB_INVALID_ADDRESS;
704             m_page_to_free_size = 0;
705             if (error.Success())
706             {
707 
708                 if (queue_info_pointer.count > 0
709                     && queue_info_pointer.queues_buffer_size > 0
710                     && queue_info_pointer.queues_buffer_ptr != 0
711                     && queue_info_pointer.queues_buffer_ptr != LLDB_INVALID_ADDRESS)
712                 {
713                     PopulateQueuesUsingLibBTR (queue_info_pointer.queues_buffer_ptr, queue_info_pointer.queues_buffer_size, queue_info_pointer.count, queue_list);
714                 }
715             }
716         }
717     }
718 
719     // We either didn't have libBacktraceRecording (and need to create the queues list based on threads)
720     // or we did get the queues list from libBacktraceRecording but some special queues may not be
721     // included in its information.  This is needed because libBacktraceRecording
722     // will only list queues with pending or running items by default - but the magic com.apple.main-thread
723     // queue on thread 1 is always around.
724 
725     for (ThreadSP thread_sp : m_process->Threads())
726     {
727         if (thread_sp->GetQueueID() != LLDB_INVALID_QUEUE_ID)
728         {
729             if (queue_list.FindQueueByID (thread_sp->GetQueueID()).get() == NULL)
730             {
731                 QueueSP queue_sp (new Queue(m_process->shared_from_this(), thread_sp->GetQueueID(), thread_sp->GetQueueName()));
732                 queue_sp->SetKind (GetQueueKind (thread_sp->GetQueueLibdispatchQueueAddress()));
733                 queue_sp->SetLibdispatchQueueAddress (thread_sp->GetQueueLibdispatchQueueAddress());
734                 queue_list.AddQueue (queue_sp);
735             }
736         }
737     }
738 }
739 
740 // Returns either an array of introspection_dispatch_item_info_ref's for the pending items on
741 // a queue or an array introspection_dispatch_item_info_ref's and code addresses for the
742 // pending items on a queue.  The information about each of these pending items then needs to
743 // be fetched individually by passing the ref to libBacktraceRecording.
744 
745 SystemRuntimeMacOSX::PendingItemsForQueue
746 SystemRuntimeMacOSX::GetPendingItemRefsForQueue (lldb::addr_t queue)
747 {
748     PendingItemsForQueue pending_item_refs;
749     AppleGetPendingItemsHandler::GetPendingItemsReturnInfo pending_items_pointer;
750     ThreadSP cur_thread_sp (m_process->GetThreadList().GetSelectedThread());
751     if (cur_thread_sp)
752     {
753         Error error;
754         pending_items_pointer = m_get_pending_items_handler.GetPendingItems (*cur_thread_sp.get(), queue, m_page_to_free, m_page_to_free_size, error);
755         m_page_to_free = LLDB_INVALID_ADDRESS;
756         m_page_to_free_size = 0;
757         if (error.Success())
758         {
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             {
764                 DataBufferHeap data (pending_items_pointer.items_buffer_size, 0);
765                 if (m_process->ReadMemory (pending_items_pointer.items_buffer_ptr, data.GetBytes(), pending_items_pointer.items_buffer_size, error))
766                 {
767                     DataExtractor extractor (data.GetBytes(), data.GetByteSize(), m_process->GetByteOrder(), m_process->GetAddressByteSize());
768 
769                     // We either have an array of
770                     //    void* item_ref
771                     // (old style) or we have a structure returned which looks like
772                     //
773                     // struct introspection_dispatch_pending_item_info_s {
774                     //   void *item_ref;
775                     //   void *function_or_block;
776                     // };
777                     //
778                     // struct introspection_dispatch_pending_items_array_s {
779                     //   uint32_t version;
780                     //   uint32_t size_of_item_info;
781                     //   introspection_dispatch_pending_item_info_s items[];
782                     //   }
783 
784                     offset_t offset = 0;
785                     int i = 0;
786                     uint32_t version = extractor.GetU32(&offset);
787                     if (version == 1)
788                     {
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                         {
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                     }
803                     else
804                     {
805                         offset = 0;
806                         pending_item_refs.new_style = false;
807                         while (offset < pending_items_pointer.items_buffer_size &&
808                                static_cast<size_t>(i) < pending_items_pointer.count)
809                         {
810                             ItemRefAndCodeAddress item;
811                             item.item_ref = extractor.GetPointer (&offset);
812                             item.code_address = LLDB_INVALID_ADDRESS;
813                             pending_item_refs.item_refs_and_code_addresses.push_back (item);
814                             i++;
815                         }
816                     }
817                 }
818                 m_page_to_free = pending_items_pointer.items_buffer_ptr;
819                 m_page_to_free_size = pending_items_pointer.items_buffer_size;
820             }
821         }
822     }
823     return pending_item_refs;
824 }
825 
826 
827 
828 void
829 SystemRuntimeMacOSX::PopulatePendingItemsForQueue (Queue *queue)
830 {
831     if (BacktraceRecordingHeadersInitialized())
832     {
833         PendingItemsForQueue pending_item_refs = GetPendingItemRefsForQueue (queue->GetLibdispatchQueueAddress());
834         for (ItemRefAndCodeAddress pending_item : pending_item_refs.item_refs_and_code_addresses)
835         {
836             Address addr;
837             m_process->GetTarget().ResolveLoadAddress (pending_item.code_address, addr);
838             QueueItemSP queue_item_sp (new QueueItem (queue->shared_from_this(), m_process->shared_from_this(), pending_item.item_ref, addr));
839             queue->PushPendingQueueItem (queue_item_sp);
840         }
841     }
842 }
843 
844 void
845 SystemRuntimeMacOSX::CompleteQueueItem (QueueItem *queue_item, addr_t item_ref)
846 {
847     AppleGetItemInfoHandler::GetItemInfoReturnInfo ret;
848 
849     ThreadSP cur_thread_sp (m_process->GetThreadList().GetSelectedThread());
850     Error error;
851     ret = m_get_item_info_handler.GetItemInfo (*cur_thread_sp.get(), item_ref, m_page_to_free, m_page_to_free_size, error);
852     m_page_to_free = LLDB_INVALID_ADDRESS;
853     m_page_to_free_size = 0;
854     if (ret.item_buffer_ptr != 0 &&  ret.item_buffer_ptr != LLDB_INVALID_ADDRESS && ret.item_buffer_size > 0)
855     {
856         DataBufferHeap data (ret.item_buffer_size, 0);
857         if (m_process->ReadMemory (ret.item_buffer_ptr, data.GetBytes(), ret.item_buffer_size, error) && error.Success())
858         {
859             DataExtractor extractor (data.GetBytes(), data.GetByteSize(), m_process->GetByteOrder(), 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
876 SystemRuntimeMacOSX::PopulateQueuesUsingLibBTR (lldb::addr_t queues_buffer, uint64_t queues_buffer_size,
877                                                 uint64_t count, lldb_private::QueueList &queue_list)
878 {
879     Error 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, error) == queues_buffer_size && error.Success())
883     {
884         // We've read the information out of inferior memory; free it on the next call we make
885         m_page_to_free = queues_buffer;
886         m_page_to_free_size = queues_buffer_size;
887 
888         DataExtractor extractor (data.GetBytes(), data.GetByteSize(), m_process->GetByteOrder(), m_process->GetAddressByteSize());
889         offset_t offset = 0;
890         uint64_t queues_read = 0;
891 
892         // The information about the queues is stored in this format (v1):
893         // typedef struct introspection_dispatch_queue_info_s {
894         //     uint32_t offset_to_next;
895         //     dispatch_queue_t queue;
896         //     uint64_t serialnum;     // queue's serialnum in the process, as provided by libdispatch
897         //     uint32_t running_work_items_count;
898         //     uint32_t pending_work_items_count;
899         //
900         //     char data[];     // Starting here, we have variable-length data:
901         //     // char queue_label[];
902         // } introspection_dispatch_queue_info_s;
903 
904         while (queues_read < count && offset < queues_buffer_size)
905         {
906             offset_t    start_of_this_item = offset;
907 
908             uint32_t    offset_to_next = extractor.GetU32 (&offset);
909 
910             offset += 4; // Skip over the 4 bytes of reserved space
911             addr_t      queue = extractor.GetPointer (&offset);
912             uint64_t    serialnum = extractor.GetU64 (&offset);
913             uint32_t    running_work_items_count = extractor.GetU32 (&offset);
914             uint32_t    pending_work_items_count = extractor.GetU32 (&offset);
915 
916             // Read the first field of the variable length data
917             offset = start_of_this_item + m_lib_backtrace_recording_info.queue_info_data_offset;
918             const char *queue_label = extractor.GetCStr (&offset);
919             if (queue_label == NULL)
920                 queue_label = "";
921 
922             offset_t    start_of_next_item = start_of_this_item + offset_to_next;
923             offset = start_of_next_item;
924 
925             if (log)
926                 log->Printf ("SystemRuntimeMacOSX::PopulateQueuesUsingLibBTR added queue with dispatch_queue_t 0x%" PRIx64 ", serial number 0x%" PRIx64 ", running items %d, pending items %d, name '%s'", queue, serialnum, running_work_items_count, pending_work_items_count, queue_label);
927 
928             QueueSP queue_sp (new Queue (m_process->shared_from_this(), serialnum, queue_label));
929             queue_sp->SetNumRunningWorkItems (running_work_items_count);
930             queue_sp->SetNumPendingWorkItems (pending_work_items_count);
931             queue_sp->SetLibdispatchQueueAddress (queue);
932             queue_sp->SetKind (GetQueueKind (queue));
933             queue_list.AddQueue (queue_sp);
934             queues_read++;
935         }
936     }
937 }
938 
939 SystemRuntimeMacOSX::ItemInfo
940 SystemRuntimeMacOSX::ExtractItemInfoFromBuffer (lldb_private::DataExtractor &extractor)
941 {
942     ItemInfo item;
943 
944     offset_t offset = 0;
945 
946     item.item_that_enqueued_this = extractor.GetPointer (&offset);
947     item.function_or_block = extractor.GetPointer (&offset);
948     item.enqueuing_thread_id = extractor.GetU64 (&offset);
949     item.enqueuing_queue_serialnum = extractor.GetU64 (&offset);
950     item.target_queue_serialnum = extractor.GetU64 (&offset);
951     item.enqueuing_callstack_frame_count = extractor.GetU32 (&offset);
952     item.stop_id = extractor.GetU32 (&offset);
953 
954     offset = m_lib_backtrace_recording_info.item_info_data_offset;
955 
956     for (uint32_t i = 0; i < item.enqueuing_callstack_frame_count; i++)
957     {
958         item.enqueuing_callstack.push_back (extractor.GetPointer (&offset));
959     }
960     item.enqueuing_thread_label = extractor.GetCStr (&offset);
961     item.enqueuing_queue_label = extractor.GetCStr (&offset);
962     item.target_queue_label = extractor.GetCStr (&offset);
963 
964     return item;
965 }
966 
967 void
968 SystemRuntimeMacOSX::Initialize()
969 {
970     PluginManager::RegisterPlugin (GetPluginNameStatic(),
971                                    GetPluginDescriptionStatic(),
972                                    CreateInstance);
973 }
974 
975 void
976 SystemRuntimeMacOSX::Terminate()
977 {
978     PluginManager::UnregisterPlugin (CreateInstance);
979 }
980 
981 
982 lldb_private::ConstString
983 SystemRuntimeMacOSX::GetPluginNameStatic()
984 {
985     static ConstString g_name("systemruntime-macosx");
986     return g_name;
987 }
988 
989 const char *
990 SystemRuntimeMacOSX::GetPluginDescriptionStatic()
991 {
992     return "System runtime plugin for Mac OS X native libraries.";
993 }
994 
995 
996 //------------------------------------------------------------------
997 // PluginInterface protocol
998 //------------------------------------------------------------------
999 lldb_private::ConstString
1000 SystemRuntimeMacOSX::GetPluginName()
1001 {
1002     return GetPluginNameStatic();
1003 }
1004 
1005 uint32_t
1006 SystemRuntimeMacOSX::GetPluginVersion()
1007 {
1008     return 1;
1009 }
1010