1 //===-- ThreadPlanStepOut.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/ThreadPlanStepOut.h"
11 
12 // C Includes
13 // C++ Includes
14 // Other libraries and framework includes
15 // Project includes
16 #include "lldb/Breakpoint/Breakpoint.h"
17 #include "lldb/lldb-private-log.h"
18 #include "lldb/Core/Log.h"
19 #include "lldb/Target/Process.h"
20 #include "lldb/Target/RegisterContext.h"
21 #include "lldb/Target/StopInfo.h"
22 #include "lldb/Target/Target.h"
23 #include "lldb/Target/ThreadPlanStepOverRange.h"
24 
25 using namespace lldb;
26 using namespace lldb_private;
27 
28 //----------------------------------------------------------------------
29 // ThreadPlanStepOut: Step out of the current frame
30 //----------------------------------------------------------------------
31 
32 ThreadPlanStepOut::ThreadPlanStepOut
33 (
34     Thread &thread,
35     SymbolContext *context,
36     bool first_insn,
37     bool stop_others,
38     Vote stop_vote,
39     Vote run_vote,
40     uint32_t frame_idx
41 ) :
42     ThreadPlan (ThreadPlan::eKindStepOut, "Step out", thread, stop_vote, run_vote),
43     m_step_from_context (context),
44     m_step_from_insn (LLDB_INVALID_ADDRESS),
45     m_return_bp_id (LLDB_INVALID_BREAK_ID),
46     m_return_addr (LLDB_INVALID_ADDRESS),
47     m_first_insn (first_insn),
48     m_stop_others (stop_others),
49     m_step_through_inline_plan_sp(),
50     m_step_out_plan_sp ()
51 
52 {
53     m_step_from_insn = m_thread.GetRegisterContext()->GetPC(0);
54 
55     StackFrameSP return_frame_sp (m_thread.GetStackFrameAtIndex(frame_idx + 1));
56     StackFrameSP immediate_return_from_sp (m_thread.GetStackFrameAtIndex (frame_idx));
57 
58     m_stack_depth = m_thread.GetStackFrameCount() - frame_idx;
59 
60     // If the frame directly below the one we are returning to is inlined, we have to be
61     // a little more careful.  It is non-trivial to determine the real "return code address" for
62     // an inlined frame, so we have to work our way to that frame and then step out.
63     if (immediate_return_from_sp && immediate_return_from_sp->IsInlined())
64     {
65         if (frame_idx > 0)
66         {
67             // First queue a plan that gets us to this inlined frame, and when we get there we'll queue a second
68             // plan that walks us out of this frame.
69             m_step_out_plan_sp.reset (new ThreadPlanStepOut(m_thread, NULL, false, stop_others, eVoteNoOpinion, eVoteNoOpinion, frame_idx - 1));
70             m_step_out_plan_sp->SetOkayToDiscard(true);
71         }
72         else
73         {
74             // If we're already at the inlined frame we're stepping through, then just do that now.
75             QueueInlinedStepPlan(false);
76         }
77 
78     }
79     else if (return_frame_sp)
80     {
81         // Find the return address and set a breakpoint there:
82         // FIXME - can we do this more securely if we know first_insn?
83 
84         m_return_addr = return_frame_sp->GetFrameCodeAddress().GetLoadAddress(&m_thread.GetProcess().GetTarget());
85         Breakpoint *return_bp = m_thread.GetProcess().GetTarget().CreateBreakpoint (m_return_addr, true).get();
86         if (return_bp != NULL)
87         {
88             return_bp->SetThreadID(m_thread.GetID());
89             m_return_bp_id = return_bp->GetID();
90         }
91     }
92 
93 }
94 
95 void
96 ThreadPlanStepOut::DidPush()
97 {
98     if (m_step_out_plan_sp)
99         m_thread.QueueThreadPlan(m_step_out_plan_sp, false);
100     else if (m_step_through_inline_plan_sp)
101         m_thread.QueueThreadPlan(m_step_through_inline_plan_sp, false);
102 }
103 
104 ThreadPlanStepOut::~ThreadPlanStepOut ()
105 {
106     if (m_return_bp_id != LLDB_INVALID_BREAK_ID)
107         m_thread.GetProcess().GetTarget().RemoveBreakpointByID(m_return_bp_id);
108 }
109 
110 void
111 ThreadPlanStepOut::GetDescription (Stream *s, lldb::DescriptionLevel level)
112 {
113     if (level == lldb::eDescriptionLevelBrief)
114         s->Printf ("step out");
115     else
116     {
117         if (m_step_out_plan_sp)
118             s->Printf ("Stepping out to inlined frame at depth: %d so we can walk through it.", m_stack_depth);
119         else if (m_step_through_inline_plan_sp)
120             s->Printf ("Stepping out by stepping through inlined function.");
121         else
122             s->Printf ("Stepping out from address 0x%llx to return address 0x%llx at depth: %d using breakpoint site %d",
123                        (uint64_t)m_step_from_insn,
124                        (uint64_t)m_return_addr,
125                        m_stack_depth,
126                        m_return_bp_id);
127     }
128 }
129 
130 bool
131 ThreadPlanStepOut::ValidatePlan (Stream *error)
132 {
133     if (m_step_out_plan_sp)
134         return m_step_out_plan_sp->ValidatePlan (error);
135     else if (m_step_through_inline_plan_sp)
136         return m_step_through_inline_plan_sp->ValidatePlan (error);
137     else if (m_return_bp_id == LLDB_INVALID_BREAK_ID)
138     {
139         error->PutCString("Could not create return address breakpoint.");
140         return false;
141     }
142     else
143         return true;
144 }
145 
146 bool
147 ThreadPlanStepOut::PlanExplainsStop ()
148 {
149     // If one of our child plans just finished, then we do explain the stop.
150     if (m_step_out_plan_sp)
151     {
152         if (m_step_out_plan_sp->MischiefManaged())
153         {
154             // If this one is done, then we are all done.
155             SetPlanComplete();
156             return true;
157         }
158         else
159             return false;
160     }
161     else if (m_step_through_inline_plan_sp)
162     {
163         if (m_step_through_inline_plan_sp->MischiefManaged())
164             return true;
165         else
166             return false;
167     }
168 
169     // We don't explain signals or breakpoints (breakpoints that handle stepping in or
170     // out will be handled by a child plan.
171 
172     StopInfoSP stop_info_sp = GetPrivateStopReason();
173     if (stop_info_sp)
174     {
175         StopReason reason = stop_info_sp->GetStopReason();
176         switch (reason)
177         {
178         case eStopReasonBreakpoint:
179         {
180             // If this is OUR breakpoint, we're fine, otherwise we don't know why this happened...
181             BreakpointSiteSP site_sp (m_thread.GetProcess().GetBreakpointSiteList().FindByID (stop_info_sp->GetValue()));
182             if (site_sp && site_sp->IsBreakpointAtThisSite (m_return_bp_id))
183             {
184                 const uint32_t num_frames = m_thread.GetStackFrameCount();
185                 if (m_stack_depth > num_frames)
186                     SetPlanComplete();
187 
188                 // If there was only one owner, then we're done.  But if we also hit some
189                 // user breakpoint on our way out, we should mark ourselves as done, but
190                 // also not claim to explain the stop, since it is more important to report
191                 // the user breakpoint than the step out completion.
192 
193                 if (site_sp->GetNumberOfOwners() == 1)
194                     return true;
195 
196             }
197             return false;
198         }
199         case eStopReasonWatchpoint:
200         case eStopReasonSignal:
201         case eStopReasonException:
202             return false;
203 
204         default:
205             return true;
206         }
207     }
208     return true;
209 }
210 
211 bool
212 ThreadPlanStepOut::ShouldStop (Event *event_ptr)
213 {
214         if (IsPlanComplete())
215         {
216             return true;
217         }
218         else if (m_stack_depth > m_thread.GetStackFrameCount())
219         {
220             SetPlanComplete();
221             return true;
222         }
223         else
224         {
225             if (m_step_out_plan_sp)
226             {
227                 if (m_step_out_plan_sp->MischiefManaged())
228                 {
229                     // Now step through the inlined stack we are in:
230                     if (QueueInlinedStepPlan(true))
231                     {
232                         return false;
233                     }
234                     else
235                     {
236                         SetPlanComplete ();
237                         return true;
238                     }
239                 }
240                 else
241                     return m_step_out_plan_sp->ShouldStop(event_ptr);
242             }
243             else if (m_step_through_inline_plan_sp)
244             {
245                 if (m_step_through_inline_plan_sp->MischiefManaged())
246                 {
247                     SetPlanComplete();
248                     return true;
249                 }
250                 else
251                     return m_step_through_inline_plan_sp->ShouldStop(event_ptr);
252             }
253             else
254                 return false;
255         }
256 }
257 
258 bool
259 ThreadPlanStepOut::StopOthers ()
260 {
261     return m_stop_others;
262 }
263 
264 StateType
265 ThreadPlanStepOut::GetPlanRunState ()
266 {
267     return eStateRunning;
268 }
269 
270 bool
271 ThreadPlanStepOut::WillResume (StateType resume_state, bool current_plan)
272 {
273     ThreadPlan::WillResume (resume_state, current_plan);
274     if (m_step_out_plan_sp || m_step_through_inline_plan_sp)
275         return true;
276 
277     if (m_return_bp_id == LLDB_INVALID_BREAK_ID)
278         return false;
279 
280     if (current_plan)
281     {
282         Breakpoint *return_bp = m_thread.GetProcess().GetTarget().GetBreakpointByID(m_return_bp_id).get();
283         if (return_bp != NULL)
284             return_bp->SetEnabled (true);
285     }
286     return true;
287 }
288 
289 bool
290 ThreadPlanStepOut::WillStop ()
291 {
292     if (m_return_bp_id != LLDB_INVALID_BREAK_ID)
293     {
294         Breakpoint *return_bp = m_thread.GetProcess().GetTarget().GetBreakpointByID(m_return_bp_id).get();
295         if (return_bp != NULL)
296             return_bp->SetEnabled (false);
297     }
298 
299     return true;
300 }
301 
302 bool
303 ThreadPlanStepOut::MischiefManaged ()
304 {
305     if (IsPlanComplete())
306     {
307         // Did I reach my breakpoint?  If so I'm done.
308         //
309         // I also check the stack depth, since if we've blown past the breakpoint for some
310         // reason and we're now stopping for some other reason altogether, then we're done
311         // with this step out operation.
312 
313         LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
314         if (log)
315             log->Printf("Completed step out plan.");
316         if (m_return_bp_id != LLDB_INVALID_BREAK_ID)
317         {
318             m_thread.GetProcess().GetTarget().RemoveBreakpointByID (m_return_bp_id);
319             m_return_bp_id = LLDB_INVALID_BREAK_ID;
320         }
321 
322         ThreadPlan::MischiefManaged ();
323         return true;
324     }
325     else
326     {
327         return false;
328     }
329 }
330 
331 bool
332 ThreadPlanStepOut::QueueInlinedStepPlan (bool queue_now)
333 {
334     // Now figure out the range of this inlined block, and set up a "step through range"
335     // plan for that.  If we've been provided with a context, then use the block in that
336     // context.
337     StackFrameSP immediate_return_from_sp (m_thread.GetStackFrameAtIndex (0));
338     if (!immediate_return_from_sp)
339         return false;
340 
341     LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
342     if (log)
343     {
344         StreamString s;
345         immediate_return_from_sp->Dump(&s, true, false);
346         log->Printf("Queuing inlined frame to step past: %s.", s.GetData());
347     }
348 
349     Block *from_block = immediate_return_from_sp->GetFrameBlock();
350     if (from_block)
351     {
352         Block *inlined_block = from_block->GetContainingInlinedBlock();
353         if (inlined_block)
354         {
355             size_t num_ranges = inlined_block->GetNumRanges();
356             AddressRange inline_range;
357             if (inlined_block->GetRangeAtIndex(0, inline_range))
358             {
359                 SymbolContext inlined_sc;
360                 inlined_block->CalculateSymbolContext(&inlined_sc);
361                 RunMode run_mode = m_stop_others ? lldb::eOnlyThisThread : lldb::eAllThreads;
362                 ThreadPlanStepOverRange *step_through_inline_plan_ptr = new ThreadPlanStepOverRange(m_thread,
363                                                                                                     inline_range,
364                                                                                                     inlined_sc,
365                                                                                                     run_mode);
366                 step_through_inline_plan_ptr->SetOkayToDiscard(true);
367                 StreamString errors;
368                 if (!step_through_inline_plan_ptr->ValidatePlan(&errors))
369                 {
370                     //FIXME: Log this failure.
371                     delete step_through_inline_plan_ptr;
372                     return false;
373                 }
374 
375                 for (size_t i = 1; i < num_ranges; i++)
376                 {
377                     if (inlined_block->GetRangeAtIndex (i, inline_range))
378                         step_through_inline_plan_ptr->AddRange (inline_range);
379                 }
380                 m_step_through_inline_plan_sp.reset (step_through_inline_plan_ptr);
381                 if (queue_now)
382                     m_thread.QueueThreadPlan (m_step_through_inline_plan_sp, false);
383                 return true;
384             }
385         }
386     }
387 
388     return false;
389 }
390