1 //===-- StackFrameList.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 #include "lldb/Target/StackFrameList.h"
11 
12 // C Includes
13 // C++ Includes
14 // Other libraries and framework includes
15 // Project includes
16 #include "lldb/Core/StreamFile.h"
17 #include "lldb/Core/SourceManager.h"
18 #include "lldb/Symbol/Block.h"
19 #include "lldb/Symbol/Function.h"
20 #include "lldb/Symbol/Symbol.h"
21 #include "lldb/Target/Process.h"
22 #include "lldb/Target/RegisterContext.h"
23 #include "lldb/Target/StackFrame.h"
24 #include "lldb/Target/StopInfo.h"
25 #include "lldb/Target/Target.h"
26 #include "lldb/Target/Thread.h"
27 #include "lldb/Target/Unwind.h"
28 
29 //#define DEBUG_STACK_FRAMES 1
30 
31 using namespace lldb;
32 using namespace lldb_private;
33 
34 //----------------------------------------------------------------------
35 // StackFrameList constructor
36 //----------------------------------------------------------------------
37 StackFrameList::StackFrameList
38 (
39     Thread &thread,
40     const lldb::StackFrameListSP &prev_frames_sp,
41     bool show_inline_frames
42 ) :
43     m_thread (thread),
44     m_prev_frames_sp (prev_frames_sp),
45     m_mutex (Mutex::eMutexTypeRecursive),
46     m_frames (),
47     m_selected_frame_idx (0),
48     m_concrete_frames_fetched (0),
49     m_current_inlined_depth (UINT32_MAX),
50     m_current_inlined_pc (LLDB_INVALID_ADDRESS),
51     m_show_inlined_frames (show_inline_frames)
52 {
53     if (prev_frames_sp)
54     {
55         m_current_inlined_depth = prev_frames_sp->m_current_inlined_depth;
56         m_current_inlined_pc =    prev_frames_sp->m_current_inlined_pc;
57     }
58 }
59 
60 //----------------------------------------------------------------------
61 // Destructor
62 //----------------------------------------------------------------------
63 StackFrameList::~StackFrameList()
64 {
65 }
66 
67 void
68 StackFrameList::CalculateCurrentInlinedDepth()
69 {
70     uint32_t cur_inlined_depth = GetCurrentInlinedDepth();
71     if (cur_inlined_depth == UINT32_MAX)
72     {
73         ResetCurrentInlinedDepth();
74     }
75 }
76 
77 uint32_t
78 StackFrameList::GetCurrentInlinedDepth ()
79 {
80     if (m_show_inlined_frames)
81     {
82         lldb::addr_t cur_pc = m_thread.GetRegisterContext()->GetPC();
83         if (cur_pc != m_current_inlined_pc)
84         {
85             m_current_inlined_pc = LLDB_INVALID_ADDRESS;
86             m_current_inlined_depth = UINT32_MAX;
87         }
88         return m_current_inlined_depth;
89     }
90     else
91     {
92         return UINT32_MAX;
93     }
94 }
95 
96 void
97 StackFrameList::ResetCurrentInlinedDepth ()
98 {
99     if (m_show_inlined_frames)
100     {
101         GetFramesUpTo(0);
102         if (!m_frames[0]->IsInlined())
103         {
104             m_current_inlined_depth = UINT32_MAX;
105             m_current_inlined_pc = LLDB_INVALID_ADDRESS;
106         }
107         else
108         {
109             // We only need to do something special about inlined blocks when we
110             // are at the beginning of an inlined function:
111             // FIXME: We probably also have to do something special if the PC is at the END
112             // of an inlined function, which coincides with the end of either its containing
113             // function or another inlined function.
114 
115             lldb::addr_t curr_pc = m_thread.GetRegisterContext()->GetPC();
116             Block *block_ptr = m_frames[0]->GetFrameBlock();
117             if (block_ptr)
118             {
119                 Address pc_as_address;
120                 pc_as_address.SetLoadAddress(curr_pc, &(m_thread.GetProcess()->GetTarget()));
121                 AddressRange containing_range;
122                 if (block_ptr->GetRangeContainingAddress(pc_as_address, containing_range))
123                 {
124                     if (pc_as_address == containing_range.GetBaseAddress())
125                     {
126                         // If we got here because of a breakpoint hit, then set the inlined depth depending on where
127                         // the breakpoint was set.
128                         // If we got here because of a crash, then set the inlined depth to the deepest most block.
129                         // Otherwise, we stopped here naturally as the result of a step, so set ourselves in the
130                         // containing frame of the whole set of nested inlines, so the user can then "virtually"
131                         // step into the frames one by one, or next over the whole mess.
132                         // Note: We don't have to handle being somewhere in the middle of the stack here, since
133                         // ResetCurrentInlinedDepth doesn't get called if there is a valid inlined depth set.
134                         StopInfoSP stop_info_sp = m_thread.GetStopInfo();
135                         if (stop_info_sp)
136                         {
137                             switch (stop_info_sp->GetStopReason())
138                             {
139                             case eStopReasonBreakpoint:
140                                 {
141 
142                                 }
143                                 break;
144                             case eStopReasonWatchpoint:
145                             case eStopReasonException:
146                             case eStopReasonSignal:
147                                 // In all these cases we want to stop in the deepest most frame.
148                                 m_current_inlined_pc = curr_pc;
149                                 m_current_inlined_depth = 0;
150                                 break;
151                             default:
152                                 {
153                                     // Otherwise, we should set ourselves at the container of the inlining, so that the
154                                     // user can descend into them.
155                                     // So first we check whether we have more than one inlined block sharing this PC:
156                                     int num_inlined_functions = 0;
157 
158                                     for  (Block *container_ptr = block_ptr->GetInlinedParent();
159                                               container_ptr != NULL;
160                                               container_ptr = container_ptr->GetInlinedParent())
161                                     {
162                                         if (!container_ptr->GetRangeContainingAddress(pc_as_address, containing_range))
163                                             break;
164                                         if (pc_as_address != containing_range.GetBaseAddress())
165                                             break;
166 
167                                         num_inlined_functions++;
168                                     }
169                                     m_current_inlined_pc = curr_pc;
170                                     m_current_inlined_depth = num_inlined_functions + 1;
171 
172                                 }
173                                 break;
174                             }
175                         }
176                     }
177                 }
178             }
179         }
180     }
181 }
182 
183 bool
184 StackFrameList::DecrementCurrentInlinedDepth ()
185 {
186     if (m_show_inlined_frames)
187     {
188         uint32_t current_inlined_depth = GetCurrentInlinedDepth();
189         if (current_inlined_depth != UINT32_MAX)
190         {
191             if (current_inlined_depth > 0)
192                 m_current_inlined_depth--;
193             return true;
194         }
195     }
196     return false;
197 }
198 
199 void
200 StackFrameList::GetFramesUpTo(uint32_t end_idx)
201 {
202     // We've already gotten more frames than asked for, or we've already finished unwinding, return.
203     if (m_frames.size() > end_idx || GetAllFramesFetched())
204         return;
205 
206     Unwind *unwinder = m_thread.GetUnwinder ();
207 
208     if (m_show_inlined_frames)
209     {
210 #if defined (DEBUG_STACK_FRAMES)
211         StreamFile s(stdout, false);
212 #endif
213         // If we are hiding some frames from the outside world, we need to add those onto the total count of
214         // frames to fetch.  However, we don't need ot do that if end_idx is 0 since in that case we always
215         // get the first concrete frame and all the inlined frames below it...
216 
217         uint32_t inlined_depth = 0;
218         if (end_idx > 0)
219         {
220             inlined_depth = GetCurrentInlinedDepth();
221             if (inlined_depth != UINT32_MAX)
222             {
223                 if (end_idx > 0)
224                     end_idx += inlined_depth;
225             }
226             else
227                 inlined_depth = 0;
228         }
229 
230         StackFrameSP unwind_frame_sp;
231         do
232         {
233             uint32_t idx = m_concrete_frames_fetched++;
234             lldb::addr_t pc;
235             lldb::addr_t cfa;
236             if (idx == 0)
237             {
238                 // We might have already created frame zero, only create it
239                 // if we need to
240                 if (m_frames.empty())
241                 {
242                     m_thread.GetRegisterContext();
243                     assert (m_thread.m_reg_context_sp.get());
244 
245                     const bool success = unwinder->GetFrameInfoAtIndex(idx, cfa, pc);
246                     // There shouldn't be any way not to get the frame info for frame 0.
247                     // But if the unwinder can't make one, lets make one by hand with the
248                     // SP as the CFA and see if that gets any further.
249                     if (!success)
250                     {
251                         cfa = m_thread.GetRegisterContext()->GetSP();
252                         pc = m_thread.GetRegisterContext()->GetPC();
253                     }
254 
255                     unwind_frame_sp.reset (new StackFrame (m_thread.shared_from_this(),
256                                                            m_frames.size(),
257                                                            idx,
258                                                            m_thread.m_reg_context_sp,
259                                                            cfa,
260                                                            pc,
261                                                            NULL));
262                     m_frames.push_back (unwind_frame_sp);
263                 }
264                 else
265                 {
266                     unwind_frame_sp = m_frames.front();
267                     cfa = unwind_frame_sp->m_id.GetCallFrameAddress();
268                 }
269             }
270             else
271             {
272                 const bool success = unwinder->GetFrameInfoAtIndex(idx, cfa, pc);
273                 if (!success)
274                 {
275                     // We've gotten to the end of the stack.
276                     SetAllFramesFetched();
277                     break;
278                 }
279                 unwind_frame_sp.reset (new StackFrame (m_thread.shared_from_this(), m_frames.size(), idx, cfa, pc, NULL));
280                 m_frames.push_back (unwind_frame_sp);
281             }
282 
283             SymbolContext unwind_sc = unwind_frame_sp->GetSymbolContext (eSymbolContextBlock | eSymbolContextFunction);
284             Block *unwind_block = unwind_sc.block;
285             if (unwind_block)
286             {
287                 Address curr_frame_address (unwind_frame_sp->GetFrameCodeAddress());
288                 // Be sure to adjust the frame address to match the address
289                 // that was used to lookup the symbol context above. If we are
290                 // in the first concrete frame, then we lookup using the current
291                 // address, else we decrement the address by one to get the correct
292                 // location.
293                 if (idx > 0)
294                     curr_frame_address.Slide(-1);
295 
296                 SymbolContext next_frame_sc;
297                 Address next_frame_address;
298 
299                 while (unwind_sc.GetParentOfInlinedScope(curr_frame_address, next_frame_sc, next_frame_address))
300                 {
301                         StackFrameSP frame_sp(new StackFrame (m_thread.shared_from_this(),
302                                                               m_frames.size(),
303                                                               idx,
304                                                               unwind_frame_sp->GetRegisterContextSP (),
305                                                               cfa,
306                                                               next_frame_address,
307                                                               &next_frame_sc));
308 
309                         m_frames.push_back (frame_sp);
310                         unwind_sc = next_frame_sc;
311                         curr_frame_address = next_frame_address;
312                 }
313             }
314         } while (m_frames.size() - 1 < end_idx);
315 
316         // Don't try to merge till you've calculated all the frames in this stack.
317         if (GetAllFramesFetched() && m_prev_frames_sp)
318         {
319             StackFrameList *prev_frames = m_prev_frames_sp.get();
320             StackFrameList *curr_frames = this;
321 
322 #if defined (DEBUG_STACK_FRAMES)
323             s.PutCString("\nprev_frames:\n");
324             prev_frames->Dump (&s);
325             s.PutCString("\ncurr_frames:\n");
326             curr_frames->Dump (&s);
327             s.EOL();
328 #endif
329             size_t curr_frame_num, prev_frame_num;
330 
331             for (curr_frame_num = curr_frames->m_frames.size(), prev_frame_num = prev_frames->m_frames.size();
332                  curr_frame_num > 0 && prev_frame_num > 0;
333                  --curr_frame_num, --prev_frame_num)
334             {
335                 const size_t curr_frame_idx = curr_frame_num-1;
336                 const size_t prev_frame_idx = prev_frame_num-1;
337                 StackFrameSP curr_frame_sp (curr_frames->m_frames[curr_frame_idx]);
338                 StackFrameSP prev_frame_sp (prev_frames->m_frames[prev_frame_idx]);
339 
340 #if defined (DEBUG_STACK_FRAMES)
341                 s.Printf("\n\nCurr frame #%u ", curr_frame_idx);
342                 if (curr_frame_sp)
343                     curr_frame_sp->Dump (&s, true, false);
344                 else
345                     s.PutCString("NULL");
346                 s.Printf("\nPrev frame #%u ", prev_frame_idx);
347                 if (prev_frame_sp)
348                     prev_frame_sp->Dump (&s, true, false);
349                 else
350                     s.PutCString("NULL");
351 #endif
352 
353                 StackFrame *curr_frame = curr_frame_sp.get();
354                 StackFrame *prev_frame = prev_frame_sp.get();
355 
356                 if (curr_frame == NULL || prev_frame == NULL)
357                     break;
358 
359                 // Check the stack ID to make sure they are equal
360                 if (curr_frame->GetStackID() != prev_frame->GetStackID())
361                     break;
362 
363                 prev_frame->UpdatePreviousFrameFromCurrentFrame (*curr_frame);
364                 // Now copy the fixed up previous frame into the current frames
365                 // so the pointer doesn't change
366                 m_frames[curr_frame_idx] = prev_frame_sp;
367                 //curr_frame->UpdateCurrentFrameFromPreviousFrame (*prev_frame);
368 
369 #if defined (DEBUG_STACK_FRAMES)
370                 s.Printf("\n    Copying previous frame to current frame");
371 #endif
372             }
373             // We are done with the old stack frame list, we can release it now
374             m_prev_frames_sp.reset();
375         }
376 
377 #if defined (DEBUG_STACK_FRAMES)
378             s.PutCString("\n\nNew frames:\n");
379             Dump (&s);
380             s.EOL();
381 #endif
382     }
383     else
384     {
385         if (end_idx < m_concrete_frames_fetched)
386             return;
387 
388         uint32_t num_frames = unwinder->GetFramesUpTo(end_idx);
389         if (num_frames <= end_idx + 1)
390         {
391             //Done unwinding.
392             m_concrete_frames_fetched = UINT32_MAX;
393         }
394         m_frames.resize(num_frames);
395     }
396 }
397 
398 uint32_t
399 StackFrameList::GetNumFrames (bool can_create)
400 {
401     Mutex::Locker locker (m_mutex);
402 
403     if (can_create)
404         GetFramesUpTo (UINT32_MAX);
405 
406     uint32_t inlined_depth = GetCurrentInlinedDepth();
407     if (inlined_depth == UINT32_MAX)
408         return m_frames.size();
409     else
410         return m_frames.size() - inlined_depth;
411 }
412 
413 void
414 StackFrameList::Dump (Stream *s)
415 {
416     if (s == NULL)
417         return;
418     Mutex::Locker locker (m_mutex);
419 
420     const_iterator pos, begin = m_frames.begin(), end = m_frames.end();
421     for (pos = begin; pos != end; ++pos)
422     {
423         StackFrame *frame = (*pos).get();
424         s->Printf("%p: ", frame);
425         if (frame)
426         {
427             frame->GetStackID().Dump (s);
428             frame->DumpUsingSettingsFormat (s);
429         }
430         else
431             s->Printf("frame #%u", (uint32_t)std::distance (begin, pos));
432         s->EOL();
433     }
434     s->EOL();
435 }
436 
437 StackFrameSP
438 StackFrameList::GetFrameAtIndex (uint32_t idx)
439 {
440     StackFrameSP frame_sp;
441     Mutex::Locker locker (m_mutex);
442     uint32_t inlined_depth = GetCurrentInlinedDepth();
443     if (inlined_depth != UINT32_MAX)
444         idx += inlined_depth;
445 
446     if (idx < m_frames.size())
447         frame_sp = m_frames[idx];
448 
449     if (frame_sp)
450         return frame_sp;
451 
452         // GetFramesUpTo will fill m_frames with as many frames as you asked for,
453         // if there are that many.  If there weren't then you asked for too many
454         // frames.
455         GetFramesUpTo (idx);
456         if (idx < m_frames.size())
457         {
458             if (m_show_inlined_frames)
459             {
460                 // When inline frames are enabled we actually create all the frames in GetFramesUpTo.
461                 frame_sp = m_frames[idx];
462             }
463             else
464             {
465                 Unwind *unwinder = m_thread.GetUnwinder ();
466                 if (unwinder)
467                 {
468                     addr_t pc, cfa;
469                     if (unwinder->GetFrameInfoAtIndex(idx, cfa, pc))
470                     {
471                         frame_sp.reset (new StackFrame (m_thread.shared_from_this(), idx, idx, cfa, pc, NULL));
472 
473                         Function *function = frame_sp->GetSymbolContext (eSymbolContextFunction).function;
474                         if (function)
475                         {
476                             // When we aren't showing inline functions we always use
477                             // the top most function block as the scope.
478                             frame_sp->SetSymbolContextScope (&function->GetBlock(false));
479                         }
480                         else
481                         {
482                             // Set the symbol scope from the symbol regardless if it is NULL or valid.
483                             frame_sp->SetSymbolContextScope (frame_sp->GetSymbolContext (eSymbolContextSymbol).symbol);
484                         }
485                         SetFrameAtIndex(idx, frame_sp);
486                     }
487                 }
488             }
489         }
490     return frame_sp;
491 }
492 
493 StackFrameSP
494 StackFrameList::GetFrameWithConcreteFrameIndex (uint32_t unwind_idx)
495 {
496     // First try assuming the unwind index is the same as the frame index. The
497     // unwind index is always greater than or equal to the frame index, so it
498     // is a good place to start. If we have inlined frames we might have 5
499     // concrete frames (frame unwind indexes go from 0-4), but we might have 15
500     // frames after we make all the inlined frames. Most of the time the unwind
501     // frame index (or the concrete frame index) is the same as the frame index.
502     uint32_t frame_idx = unwind_idx;
503     StackFrameSP frame_sp (GetFrameAtIndex (frame_idx));
504     while (frame_sp)
505     {
506         if (frame_sp->GetFrameIndex() == unwind_idx)
507             break;
508         frame_sp = GetFrameAtIndex (++frame_idx);
509     }
510     return frame_sp;
511 }
512 
513 StackFrameSP
514 StackFrameList::GetFrameWithStackID (const StackID &stack_id)
515 {
516     uint32_t frame_idx = 0;
517     StackFrameSP frame_sp;
518     do
519     {
520         frame_sp = GetFrameAtIndex (frame_idx);
521         if (frame_sp && frame_sp->GetStackID() == stack_id)
522             break;
523         frame_idx++;
524     }
525     while (frame_sp);
526     return frame_sp;
527 }
528 
529 bool
530 StackFrameList::SetFrameAtIndex (uint32_t idx, StackFrameSP &frame_sp)
531 {
532     if (idx >= m_frames.size())
533         m_frames.resize(idx + 1);
534     // Make sure allocation succeeded by checking bounds again
535     if (idx < m_frames.size())
536     {
537         m_frames[idx] = frame_sp;
538         return true;
539     }
540     return false;   // resize failed, out of memory?
541 }
542 
543 uint32_t
544 StackFrameList::GetSelectedFrameIndex () const
545 {
546     Mutex::Locker locker (m_mutex);
547     return m_selected_frame_idx;
548 }
549 
550 
551 uint32_t
552 StackFrameList::SetSelectedFrame (lldb_private::StackFrame *frame)
553 {
554     Mutex::Locker locker (m_mutex);
555     const_iterator pos;
556     const_iterator begin = m_frames.begin();
557     const_iterator end = m_frames.end();
558     m_selected_frame_idx = 0;
559     for (pos = begin; pos != end; ++pos)
560     {
561         if (pos->get() == frame)
562         {
563             m_selected_frame_idx = std::distance (begin, pos);
564             uint32_t inlined_depth = GetCurrentInlinedDepth();
565             if (inlined_depth != UINT32_MAX)
566                 m_selected_frame_idx -= inlined_depth;
567             break;
568         }
569     }
570     SetDefaultFileAndLineToSelectedFrame();
571     return m_selected_frame_idx;
572 }
573 
574 // Mark a stack frame as the current frame using the frame index
575 bool
576 StackFrameList::SetSelectedFrameByIndex (uint32_t idx)
577 {
578     Mutex::Locker locker (m_mutex);
579     StackFrameSP frame_sp (GetFrameAtIndex (idx));
580     if (frame_sp)
581     {
582         SetSelectedFrame(frame_sp.get());
583         return true;
584     }
585     else
586         return false;
587 }
588 
589 void
590 StackFrameList::SetDefaultFileAndLineToSelectedFrame()
591 {
592     if (m_thread.GetID() == m_thread.GetProcess()->GetThreadList().GetSelectedThread()->GetID())
593     {
594         StackFrameSP frame_sp (GetFrameAtIndex (GetSelectedFrameIndex()));
595         if (frame_sp)
596         {
597             SymbolContext sc = frame_sp->GetSymbolContext(eSymbolContextLineEntry);
598             if (sc.line_entry.file)
599                 m_thread.CalculateTarget()->GetSourceManager().SetDefaultFileAndLine (sc.line_entry.file,
600                                                                                             sc.line_entry.line);
601         }
602     }
603 }
604 
605 // The thread has been run, reset the number stack frames to zero so we can
606 // determine how many frames we have lazily.
607 void
608 StackFrameList::Clear ()
609 {
610     Mutex::Locker locker (m_mutex);
611     m_frames.clear();
612     m_concrete_frames_fetched = 0;
613 }
614 
615 void
616 StackFrameList::InvalidateFrames (uint32_t start_idx)
617 {
618     Mutex::Locker locker (m_mutex);
619     if (m_show_inlined_frames)
620     {
621         Clear();
622     }
623     else
624     {
625         const size_t num_frames = m_frames.size();
626         while (start_idx < num_frames)
627         {
628             m_frames[start_idx].reset();
629             ++start_idx;
630         }
631     }
632 }
633 
634 void
635 StackFrameList::Merge (std::auto_ptr<StackFrameList>& curr_ap, lldb::StackFrameListSP& prev_sp)
636 {
637     Mutex::Locker curr_locker (curr_ap.get() ? &curr_ap->m_mutex : NULL);
638     Mutex::Locker prev_locker (prev_sp.get() ? &prev_sp->m_mutex : NULL);
639 
640 #if defined (DEBUG_STACK_FRAMES)
641     StreamFile s(stdout, false);
642     s.PutCString("\n\nStackFrameList::Merge():\nPrev:\n");
643     if (prev_sp.get())
644         prev_sp->Dump (&s);
645     else
646         s.PutCString ("NULL");
647     s.PutCString("\nCurr:\n");
648     if (curr_ap.get())
649         curr_ap->Dump (&s);
650     else
651         s.PutCString ("NULL");
652     s.EOL();
653 #endif
654 
655     if (curr_ap.get() == NULL || curr_ap->GetNumFrames (false) == 0)
656     {
657 #if defined (DEBUG_STACK_FRAMES)
658         s.PutCString("No current frames, leave previous frames alone...\n");
659 #endif
660         curr_ap.release();
661         return;
662     }
663 
664     if (prev_sp.get() == NULL || prev_sp->GetNumFrames (false) == 0)
665     {
666 #if defined (DEBUG_STACK_FRAMES)
667         s.PutCString("No previous frames, so use current frames...\n");
668 #endif
669         // We either don't have any previous frames, or since we have more than
670         // one current frames it means we have all the frames and can safely
671         // replace our previous frames.
672         prev_sp.reset (curr_ap.release());
673         return;
674     }
675 
676     const uint32_t num_curr_frames = curr_ap->GetNumFrames (false);
677 
678     if (num_curr_frames > 1)
679     {
680 #if defined (DEBUG_STACK_FRAMES)
681         s.PutCString("We have more than one current frame, so use current frames...\n");
682 #endif
683         // We have more than one current frames it means we have all the frames
684         // and can safely replace our previous frames.
685         prev_sp.reset (curr_ap.release());
686 
687 #if defined (DEBUG_STACK_FRAMES)
688         s.PutCString("\nMerged:\n");
689         prev_sp->Dump (&s);
690 #endif
691         return;
692     }
693 
694     StackFrameSP prev_frame_zero_sp(prev_sp->GetFrameAtIndex (0));
695     StackFrameSP curr_frame_zero_sp(curr_ap->GetFrameAtIndex (0));
696     StackID curr_stack_id (curr_frame_zero_sp->GetStackID());
697     StackID prev_stack_id (prev_frame_zero_sp->GetStackID());
698 
699 #if defined (DEBUG_STACK_FRAMES)
700     const uint32_t num_prev_frames = prev_sp->GetNumFrames (false);
701     s.Printf("\n%u previous frames with one current frame\n", num_prev_frames);
702 #endif
703 
704     // We have only a single current frame
705     // Our previous stack frames only had a single frame as well...
706     if (curr_stack_id == prev_stack_id)
707     {
708 #if defined (DEBUG_STACK_FRAMES)
709         s.Printf("\nPrevious frame #0 is same as current frame #0, merge the cached data\n");
710 #endif
711 
712         curr_frame_zero_sp->UpdateCurrentFrameFromPreviousFrame (*prev_frame_zero_sp);
713 //        prev_frame_zero_sp->UpdatePreviousFrameFromCurrentFrame (*curr_frame_zero_sp);
714 //        prev_sp->SetFrameAtIndex (0, prev_frame_zero_sp);
715     }
716     else if (curr_stack_id < prev_stack_id)
717     {
718 #if defined (DEBUG_STACK_FRAMES)
719         s.Printf("\nCurrent frame #0 has a stack ID that is less than the previous frame #0, insert current frame zero in front of previous\n");
720 #endif
721         prev_sp->m_frames.insert (prev_sp->m_frames.begin(), curr_frame_zero_sp);
722     }
723 
724     curr_ap.release();
725 
726 #if defined (DEBUG_STACK_FRAMES)
727     s.PutCString("\nMerged:\n");
728     prev_sp->Dump (&s);
729 #endif
730 
731 
732 }
733 
734 lldb::StackFrameSP
735 StackFrameList::GetStackFrameSPForStackFramePtr (StackFrame *stack_frame_ptr)
736 {
737     const_iterator pos;
738     const_iterator begin = m_frames.begin();
739     const_iterator end = m_frames.end();
740     lldb::StackFrameSP ret_sp;
741 
742     for (pos = begin; pos != end; ++pos)
743     {
744         if (pos->get() == stack_frame_ptr)
745         {
746             ret_sp = (*pos);
747             break;
748         }
749     }
750     return ret_sp;
751 }
752 
753 size_t
754 StackFrameList::GetStatus (Stream& strm,
755                            uint32_t first_frame,
756                            uint32_t num_frames,
757                            bool show_frame_info,
758                            uint32_t num_frames_with_source)
759 {
760     size_t num_frames_displayed = 0;
761 
762     if (num_frames == 0)
763         return 0;
764 
765     StackFrameSP frame_sp;
766     uint32_t frame_idx = 0;
767     uint32_t last_frame;
768 
769     // Don't let the last frame wrap around...
770     if (num_frames == UINT32_MAX)
771         last_frame = UINT32_MAX;
772     else
773         last_frame = first_frame + num_frames;
774 
775     for (frame_idx = first_frame; frame_idx < last_frame; ++frame_idx)
776     {
777         frame_sp = GetFrameAtIndex(frame_idx);
778         if (frame_sp.get() == NULL)
779             break;
780 
781         if (!frame_sp->GetStatus (strm,
782                                   show_frame_info,
783                                   num_frames_with_source > (first_frame - frame_idx)))
784             break;
785         ++num_frames_displayed;
786     }
787 
788     strm.IndentLess();
789     return num_frames_displayed;
790 }
791 
792