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             {
193                 m_current_inlined_depth--;
194                 return true;
195             }
196         }
197     }
198     return false;
199 }
200 
201 void
202 StackFrameList::GetFramesUpTo(uint32_t end_idx)
203 {
204     // We've already gotten more frames than asked for, or we've already finished unwinding, return.
205     if (m_frames.size() > end_idx || GetAllFramesFetched())
206         return;
207 
208     Unwind *unwinder = m_thread.GetUnwinder ();
209 
210     if (m_show_inlined_frames)
211     {
212 #if defined (DEBUG_STACK_FRAMES)
213         StreamFile s(stdout, false);
214 #endif
215         // If we are hiding some frames from the outside world, we need to add those onto the total count of
216         // frames to fetch.  However, we don't need ot do that if end_idx is 0 since in that case we always
217         // get the first concrete frame and all the inlined frames below it...
218 
219         uint32_t inlined_depth = 0;
220         if (end_idx > 0)
221         {
222             inlined_depth = GetCurrentInlinedDepth();
223             if (inlined_depth != UINT32_MAX)
224             {
225                 if (end_idx > 0)
226                     end_idx += inlined_depth;
227             }
228             else
229                 inlined_depth = 0;
230         }
231 
232         StackFrameSP unwind_frame_sp;
233         do
234         {
235             uint32_t idx = m_concrete_frames_fetched++;
236             lldb::addr_t pc;
237             lldb::addr_t cfa;
238             if (idx == 0)
239             {
240                 // We might have already created frame zero, only create it
241                 // if we need to
242                 if (m_frames.empty())
243                 {
244                     m_thread.GetRegisterContext();
245                     assert (m_thread.m_reg_context_sp.get());
246 
247                     const bool success = unwinder->GetFrameInfoAtIndex(idx, cfa, pc);
248                     // There shouldn't be any way not to get the frame info for frame 0.
249                     // But if the unwinder can't make one, lets make one by hand with the
250                     // SP as the CFA and see if that gets any further.
251                     if (!success)
252                     {
253                         cfa = m_thread.GetRegisterContext()->GetSP();
254                         pc = m_thread.GetRegisterContext()->GetPC();
255                     }
256 
257                     unwind_frame_sp.reset (new StackFrame (m_thread.shared_from_this(),
258                                                            m_frames.size(),
259                                                            idx,
260                                                            m_thread.m_reg_context_sp,
261                                                            cfa,
262                                                            pc,
263                                                            NULL));
264                     m_frames.push_back (unwind_frame_sp);
265                 }
266                 else
267                 {
268                     unwind_frame_sp = m_frames.front();
269                     cfa = unwind_frame_sp->m_id.GetCallFrameAddress();
270                 }
271             }
272             else
273             {
274                 const bool success = unwinder->GetFrameInfoAtIndex(idx, cfa, pc);
275                 if (!success)
276                 {
277                     // We've gotten to the end of the stack.
278                     SetAllFramesFetched();
279                     break;
280                 }
281                 unwind_frame_sp.reset (new StackFrame (m_thread.shared_from_this(), m_frames.size(), idx, cfa, pc, NULL));
282                 m_frames.push_back (unwind_frame_sp);
283             }
284 
285             SymbolContext unwind_sc = unwind_frame_sp->GetSymbolContext (eSymbolContextBlock | eSymbolContextFunction);
286             Block *unwind_block = unwind_sc.block;
287             if (unwind_block)
288             {
289                 Address curr_frame_address (unwind_frame_sp->GetFrameCodeAddress());
290                 // Be sure to adjust the frame address to match the address
291                 // that was used to lookup the symbol context above. If we are
292                 // in the first concrete frame, then we lookup using the current
293                 // address, else we decrement the address by one to get the correct
294                 // location.
295                 if (idx > 0)
296                     curr_frame_address.Slide(-1);
297 
298                 SymbolContext next_frame_sc;
299                 Address next_frame_address;
300 
301                 while (unwind_sc.GetParentOfInlinedScope(curr_frame_address, next_frame_sc, next_frame_address))
302                 {
303                         StackFrameSP frame_sp(new StackFrame (m_thread.shared_from_this(),
304                                                               m_frames.size(),
305                                                               idx,
306                                                               unwind_frame_sp->GetRegisterContextSP (),
307                                                               cfa,
308                                                               next_frame_address,
309                                                               &next_frame_sc));
310 
311                         m_frames.push_back (frame_sp);
312                         unwind_sc = next_frame_sc;
313                         curr_frame_address = next_frame_address;
314                 }
315             }
316         } while (m_frames.size() - 1 < end_idx);
317 
318         // Don't try to merge till you've calculated all the frames in this stack.
319         if (GetAllFramesFetched() && m_prev_frames_sp)
320         {
321             StackFrameList *prev_frames = m_prev_frames_sp.get();
322             StackFrameList *curr_frames = this;
323 
324             curr_frames->m_current_inlined_depth = prev_frames->m_current_inlined_depth;
325             curr_frames->m_current_inlined_pc = prev_frames->m_current_inlined_pc;
326 
327 #if defined (DEBUG_STACK_FRAMES)
328             s.PutCString("\nprev_frames:\n");
329             prev_frames->Dump (&s);
330             s.PutCString("\ncurr_frames:\n");
331             curr_frames->Dump (&s);
332             s.EOL();
333 #endif
334             size_t curr_frame_num, prev_frame_num;
335 
336             for (curr_frame_num = curr_frames->m_frames.size(), prev_frame_num = prev_frames->m_frames.size();
337                  curr_frame_num > 0 && prev_frame_num > 0;
338                  --curr_frame_num, --prev_frame_num)
339             {
340                 const size_t curr_frame_idx = curr_frame_num-1;
341                 const size_t prev_frame_idx = prev_frame_num-1;
342                 StackFrameSP curr_frame_sp (curr_frames->m_frames[curr_frame_idx]);
343                 StackFrameSP prev_frame_sp (prev_frames->m_frames[prev_frame_idx]);
344 
345 #if defined (DEBUG_STACK_FRAMES)
346                 s.Printf("\n\nCurr frame #%u ", curr_frame_idx);
347                 if (curr_frame_sp)
348                     curr_frame_sp->Dump (&s, true, false);
349                 else
350                     s.PutCString("NULL");
351                 s.Printf("\nPrev frame #%u ", prev_frame_idx);
352                 if (prev_frame_sp)
353                     prev_frame_sp->Dump (&s, true, false);
354                 else
355                     s.PutCString("NULL");
356 #endif
357 
358                 StackFrame *curr_frame = curr_frame_sp.get();
359                 StackFrame *prev_frame = prev_frame_sp.get();
360 
361                 if (curr_frame == NULL || prev_frame == NULL)
362                     break;
363 
364                 // Check the stack ID to make sure they are equal
365                 if (curr_frame->GetStackID() != prev_frame->GetStackID())
366                     break;
367 
368                 prev_frame->UpdatePreviousFrameFromCurrentFrame (*curr_frame);
369                 // Now copy the fixed up previous frame into the current frames
370                 // so the pointer doesn't change
371                 m_frames[curr_frame_idx] = prev_frame_sp;
372                 //curr_frame->UpdateCurrentFrameFromPreviousFrame (*prev_frame);
373 
374 #if defined (DEBUG_STACK_FRAMES)
375                 s.Printf("\n    Copying previous frame to current frame");
376 #endif
377             }
378             // We are done with the old stack frame list, we can release it now
379             m_prev_frames_sp.reset();
380         }
381 
382 #if defined (DEBUG_STACK_FRAMES)
383             s.PutCString("\n\nNew frames:\n");
384             Dump (&s);
385             s.EOL();
386 #endif
387     }
388     else
389     {
390         if (end_idx < m_concrete_frames_fetched)
391             return;
392 
393         uint32_t num_frames = unwinder->GetFramesUpTo(end_idx);
394         if (num_frames <= end_idx + 1)
395         {
396             //Done unwinding.
397             m_concrete_frames_fetched = UINT32_MAX;
398         }
399         m_frames.resize(num_frames);
400     }
401 }
402 
403 uint32_t
404 StackFrameList::GetNumFrames (bool can_create)
405 {
406     Mutex::Locker locker (m_mutex);
407 
408     if (can_create)
409         GetFramesUpTo (UINT32_MAX);
410 
411     uint32_t inlined_depth = GetCurrentInlinedDepth();
412     if (inlined_depth == UINT32_MAX)
413         return m_frames.size();
414     else
415         return m_frames.size() - inlined_depth;
416 }
417 
418 void
419 StackFrameList::Dump (Stream *s)
420 {
421     if (s == NULL)
422         return;
423     Mutex::Locker locker (m_mutex);
424 
425     const_iterator pos, begin = m_frames.begin(), end = m_frames.end();
426     for (pos = begin; pos != end; ++pos)
427     {
428         StackFrame *frame = (*pos).get();
429         s->Printf("%p: ", frame);
430         if (frame)
431         {
432             frame->GetStackID().Dump (s);
433             frame->DumpUsingSettingsFormat (s);
434         }
435         else
436             s->Printf("frame #%u", (uint32_t)std::distance (begin, pos));
437         s->EOL();
438     }
439     s->EOL();
440 }
441 
442 StackFrameSP
443 StackFrameList::GetFrameAtIndex (uint32_t idx)
444 {
445     StackFrameSP frame_sp;
446     Mutex::Locker locker (m_mutex);
447     uint32_t inlined_depth = GetCurrentInlinedDepth();
448     if (inlined_depth != UINT32_MAX)
449         idx += inlined_depth;
450 
451     if (idx < m_frames.size())
452         frame_sp = m_frames[idx];
453 
454     if (frame_sp)
455         return frame_sp;
456 
457         // GetFramesUpTo will fill m_frames with as many frames as you asked for,
458         // if there are that many.  If there weren't then you asked for too many
459         // frames.
460         GetFramesUpTo (idx);
461         if (idx < m_frames.size())
462         {
463             if (m_show_inlined_frames)
464             {
465                 // When inline frames are enabled we actually create all the frames in GetFramesUpTo.
466                 frame_sp = m_frames[idx];
467             }
468             else
469             {
470                 Unwind *unwinder = m_thread.GetUnwinder ();
471                 if (unwinder)
472                 {
473                     addr_t pc, cfa;
474                     if (unwinder->GetFrameInfoAtIndex(idx, cfa, pc))
475                     {
476                         frame_sp.reset (new StackFrame (m_thread.shared_from_this(), idx, idx, cfa, pc, NULL));
477 
478                         Function *function = frame_sp->GetSymbolContext (eSymbolContextFunction).function;
479                         if (function)
480                         {
481                             // When we aren't showing inline functions we always use
482                             // the top most function block as the scope.
483                             frame_sp->SetSymbolContextScope (&function->GetBlock(false));
484                         }
485                         else
486                         {
487                             // Set the symbol scope from the symbol regardless if it is NULL or valid.
488                             frame_sp->SetSymbolContextScope (frame_sp->GetSymbolContext (eSymbolContextSymbol).symbol);
489                         }
490                         SetFrameAtIndex(idx, frame_sp);
491                     }
492                 }
493             }
494         }
495     return frame_sp;
496 }
497 
498 StackFrameSP
499 StackFrameList::GetFrameWithConcreteFrameIndex (uint32_t unwind_idx)
500 {
501     // First try assuming the unwind index is the same as the frame index. The
502     // unwind index is always greater than or equal to the frame index, so it
503     // is a good place to start. If we have inlined frames we might have 5
504     // concrete frames (frame unwind indexes go from 0-4), but we might have 15
505     // frames after we make all the inlined frames. Most of the time the unwind
506     // frame index (or the concrete frame index) is the same as the frame index.
507     uint32_t frame_idx = unwind_idx;
508     StackFrameSP frame_sp (GetFrameAtIndex (frame_idx));
509     while (frame_sp)
510     {
511         if (frame_sp->GetFrameIndex() == unwind_idx)
512             break;
513         frame_sp = GetFrameAtIndex (++frame_idx);
514     }
515     return frame_sp;
516 }
517 
518 StackFrameSP
519 StackFrameList::GetFrameWithStackID (const StackID &stack_id)
520 {
521     uint32_t frame_idx = 0;
522     StackFrameSP frame_sp;
523     do
524     {
525         frame_sp = GetFrameAtIndex (frame_idx);
526         if (frame_sp && frame_sp->GetStackID() == stack_id)
527             break;
528         frame_idx++;
529     }
530     while (frame_sp);
531     return frame_sp;
532 }
533 
534 bool
535 StackFrameList::SetFrameAtIndex (uint32_t idx, StackFrameSP &frame_sp)
536 {
537     if (idx >= m_frames.size())
538         m_frames.resize(idx + 1);
539     // Make sure allocation succeeded by checking bounds again
540     if (idx < m_frames.size())
541     {
542         m_frames[idx] = frame_sp;
543         return true;
544     }
545     return false;   // resize failed, out of memory?
546 }
547 
548 uint32_t
549 StackFrameList::GetSelectedFrameIndex () const
550 {
551     Mutex::Locker locker (m_mutex);
552     return m_selected_frame_idx;
553 }
554 
555 
556 uint32_t
557 StackFrameList::SetSelectedFrame (lldb_private::StackFrame *frame)
558 {
559     Mutex::Locker locker (m_mutex);
560     const_iterator pos;
561     const_iterator begin = m_frames.begin();
562     const_iterator end = m_frames.end();
563     m_selected_frame_idx = 0;
564     for (pos = begin; pos != end; ++pos)
565     {
566         if (pos->get() == frame)
567         {
568             m_selected_frame_idx = std::distance (begin, pos);
569             uint32_t inlined_depth = GetCurrentInlinedDepth();
570             if (inlined_depth != UINT32_MAX)
571                 m_selected_frame_idx -= inlined_depth;
572             break;
573         }
574     }
575     SetDefaultFileAndLineToSelectedFrame();
576     return m_selected_frame_idx;
577 }
578 
579 // Mark a stack frame as the current frame using the frame index
580 bool
581 StackFrameList::SetSelectedFrameByIndex (uint32_t idx)
582 {
583     Mutex::Locker locker (m_mutex);
584     StackFrameSP frame_sp (GetFrameAtIndex (idx));
585     if (frame_sp)
586     {
587         SetSelectedFrame(frame_sp.get());
588         return true;
589     }
590     else
591         return false;
592 }
593 
594 void
595 StackFrameList::SetDefaultFileAndLineToSelectedFrame()
596 {
597     if (m_thread.GetID() == m_thread.GetProcess()->GetThreadList().GetSelectedThread()->GetID())
598     {
599         StackFrameSP frame_sp (GetFrameAtIndex (GetSelectedFrameIndex()));
600         if (frame_sp)
601         {
602             SymbolContext sc = frame_sp->GetSymbolContext(eSymbolContextLineEntry);
603             if (sc.line_entry.file)
604                 m_thread.CalculateTarget()->GetSourceManager().SetDefaultFileAndLine (sc.line_entry.file,
605                                                                                             sc.line_entry.line);
606         }
607     }
608 }
609 
610 // The thread has been run, reset the number stack frames to zero so we can
611 // determine how many frames we have lazily.
612 void
613 StackFrameList::Clear ()
614 {
615     Mutex::Locker locker (m_mutex);
616     m_frames.clear();
617     m_concrete_frames_fetched = 0;
618 }
619 
620 void
621 StackFrameList::InvalidateFrames (uint32_t start_idx)
622 {
623     Mutex::Locker locker (m_mutex);
624     if (m_show_inlined_frames)
625     {
626         Clear();
627     }
628     else
629     {
630         const size_t num_frames = m_frames.size();
631         while (start_idx < num_frames)
632         {
633             m_frames[start_idx].reset();
634             ++start_idx;
635         }
636     }
637 }
638 
639 void
640 StackFrameList::Merge (std::auto_ptr<StackFrameList>& curr_ap, lldb::StackFrameListSP& prev_sp)
641 {
642     Mutex::Locker curr_locker (curr_ap.get() ? &curr_ap->m_mutex : NULL);
643     Mutex::Locker prev_locker (prev_sp.get() ? &prev_sp->m_mutex : NULL);
644 
645 #if defined (DEBUG_STACK_FRAMES)
646     StreamFile s(stdout, false);
647     s.PutCString("\n\nStackFrameList::Merge():\nPrev:\n");
648     if (prev_sp.get())
649         prev_sp->Dump (&s);
650     else
651         s.PutCString ("NULL");
652     s.PutCString("\nCurr:\n");
653     if (curr_ap.get())
654         curr_ap->Dump (&s);
655     else
656         s.PutCString ("NULL");
657     s.EOL();
658 #endif
659 
660     if (curr_ap.get() == NULL || curr_ap->GetNumFrames (false) == 0)
661     {
662 #if defined (DEBUG_STACK_FRAMES)
663         s.PutCString("No current frames, leave previous frames alone...\n");
664 #endif
665         curr_ap.release();
666         return;
667     }
668 
669     if (prev_sp.get() == NULL || prev_sp->GetNumFrames (false) == 0)
670     {
671 #if defined (DEBUG_STACK_FRAMES)
672         s.PutCString("No previous frames, so use current frames...\n");
673 #endif
674         // We either don't have any previous frames, or since we have more than
675         // one current frames it means we have all the frames and can safely
676         // replace our previous frames.
677         prev_sp.reset (curr_ap.release());
678         return;
679     }
680 
681     const uint32_t num_curr_frames = curr_ap->GetNumFrames (false);
682 
683     if (num_curr_frames > 1)
684     {
685 #if defined (DEBUG_STACK_FRAMES)
686         s.PutCString("We have more than one current frame, so use current frames...\n");
687 #endif
688         // We have more than one current frames it means we have all the frames
689         // and can safely replace our previous frames.
690         prev_sp.reset (curr_ap.release());
691 
692 #if defined (DEBUG_STACK_FRAMES)
693         s.PutCString("\nMerged:\n");
694         prev_sp->Dump (&s);
695 #endif
696         return;
697     }
698 
699     StackFrameSP prev_frame_zero_sp(prev_sp->GetFrameAtIndex (0));
700     StackFrameSP curr_frame_zero_sp(curr_ap->GetFrameAtIndex (0));
701     StackID curr_stack_id (curr_frame_zero_sp->GetStackID());
702     StackID prev_stack_id (prev_frame_zero_sp->GetStackID());
703 
704 #if defined (DEBUG_STACK_FRAMES)
705     const uint32_t num_prev_frames = prev_sp->GetNumFrames (false);
706     s.Printf("\n%u previous frames with one current frame\n", num_prev_frames);
707 #endif
708 
709     // We have only a single current frame
710     // Our previous stack frames only had a single frame as well...
711     if (curr_stack_id == prev_stack_id)
712     {
713 #if defined (DEBUG_STACK_FRAMES)
714         s.Printf("\nPrevious frame #0 is same as current frame #0, merge the cached data\n");
715 #endif
716 
717         curr_frame_zero_sp->UpdateCurrentFrameFromPreviousFrame (*prev_frame_zero_sp);
718 //        prev_frame_zero_sp->UpdatePreviousFrameFromCurrentFrame (*curr_frame_zero_sp);
719 //        prev_sp->SetFrameAtIndex (0, prev_frame_zero_sp);
720     }
721     else if (curr_stack_id < prev_stack_id)
722     {
723 #if defined (DEBUG_STACK_FRAMES)
724         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");
725 #endif
726         prev_sp->m_frames.insert (prev_sp->m_frames.begin(), curr_frame_zero_sp);
727     }
728 
729     curr_ap.release();
730 
731 #if defined (DEBUG_STACK_FRAMES)
732     s.PutCString("\nMerged:\n");
733     prev_sp->Dump (&s);
734 #endif
735 
736 
737 }
738 
739 lldb::StackFrameSP
740 StackFrameList::GetStackFrameSPForStackFramePtr (StackFrame *stack_frame_ptr)
741 {
742     const_iterator pos;
743     const_iterator begin = m_frames.begin();
744     const_iterator end = m_frames.end();
745     lldb::StackFrameSP ret_sp;
746 
747     for (pos = begin; pos != end; ++pos)
748     {
749         if (pos->get() == stack_frame_ptr)
750         {
751             ret_sp = (*pos);
752             break;
753         }
754     }
755     return ret_sp;
756 }
757 
758 size_t
759 StackFrameList::GetStatus (Stream& strm,
760                            uint32_t first_frame,
761                            uint32_t num_frames,
762                            bool show_frame_info,
763                            uint32_t num_frames_with_source)
764 {
765     size_t num_frames_displayed = 0;
766 
767     if (num_frames == 0)
768         return 0;
769 
770     StackFrameSP frame_sp;
771     uint32_t frame_idx = 0;
772     uint32_t last_frame;
773 
774     // Don't let the last frame wrap around...
775     if (num_frames == UINT32_MAX)
776         last_frame = UINT32_MAX;
777     else
778         last_frame = first_frame + num_frames;
779 
780     for (frame_idx = first_frame; frame_idx < last_frame; ++frame_idx)
781     {
782         frame_sp = GetFrameAtIndex(frame_idx);
783         if (frame_sp.get() == NULL)
784             break;
785 
786         if (!frame_sp->GetStatus (strm,
787                                   show_frame_info,
788                                   num_frames_with_source > (first_frame - frame_idx)))
789             break;
790         ++num_frames_displayed;
791     }
792 
793     strm.IndentLess();
794     return num_frames_displayed;
795 }
796 
797