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/Core/Value.h"
20 #include "lldb/Core/ValueObjectConstResult.h"
21 #include "lldb/Symbol/Block.h"
22 #include "lldb/Symbol/Function.h"
23 #include "lldb/Symbol/Type.h"
24 #include "lldb/Target/Process.h"
25 #include "lldb/Target/RegisterContext.h"
26 #include "lldb/Target/StopInfo.h"
27 #include "lldb/Target/Target.h"
28 #include "lldb/Target/ThreadPlanStepOverRange.h"
29 
30 using namespace lldb;
31 using namespace lldb_private;
32 
33 //----------------------------------------------------------------------
34 // ThreadPlanStepOut: Step out of the current frame
35 //----------------------------------------------------------------------
36 ThreadPlanStepOut::ThreadPlanStepOut
37 (
38     Thread &thread,
39     SymbolContext *context,
40     bool first_insn,
41     bool stop_others,
42     Vote stop_vote,
43     Vote run_vote,
44     uint32_t frame_idx
45 ) :
46     ThreadPlan (ThreadPlan::eKindStepOut, "Step out", thread, stop_vote, run_vote),
47     m_step_from_context (context),
48     m_step_from_insn (LLDB_INVALID_ADDRESS),
49     m_return_bp_id (LLDB_INVALID_BREAK_ID),
50     m_return_addr (LLDB_INVALID_ADDRESS),
51     m_first_insn (first_insn),
52     m_stop_others (stop_others),
53     m_step_through_inline_plan_sp(),
54     m_step_out_plan_sp (),
55     m_immediate_step_from_function(NULL)
56 
57 {
58     m_step_from_insn = m_thread.GetRegisterContext()->GetPC(0);
59 
60     StackFrameSP return_frame_sp (m_thread.GetStackFrameAtIndex(frame_idx + 1));
61     StackFrameSP immediate_return_from_sp (m_thread.GetStackFrameAtIndex (frame_idx));
62 
63     if (!return_frame_sp || !immediate_return_from_sp)
64         return; // we can't do anything here.  ValidatePlan() will return false.
65 
66     m_step_out_to_id = return_frame_sp->GetStackID();
67     m_immediate_step_from_id = immediate_return_from_sp->GetStackID();
68 
69     StackID frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
70 
71     // If the frame directly below the one we are returning to is inlined, we have to be
72     // a little more careful.  It is non-trivial to determine the real "return code address" for
73     // an inlined frame, so we have to work our way to that frame and then step out.
74     if (immediate_return_from_sp && immediate_return_from_sp->IsInlined())
75     {
76         if (frame_idx > 0)
77         {
78             // First queue a plan that gets us to this inlined frame, and when we get there we'll queue a second
79             // plan that walks us out of this frame.
80             m_step_out_plan_sp.reset (new ThreadPlanStepOut(m_thread,
81                                                             NULL,
82                                                             false,
83                                                             stop_others,
84                                                             eVoteNoOpinion,
85                                                             eVoteNoOpinion,
86                                                             frame_idx - 1));
87         }
88         else
89         {
90             // If we're already at the inlined frame we're stepping through, then just do that now.
91             QueueInlinedStepPlan(false);
92         }
93 
94     }
95     else if (return_frame_sp)
96     {
97         // Find the return address and set a breakpoint there:
98         // FIXME - can we do this more securely if we know first_insn?
99 
100         m_return_addr = return_frame_sp->GetFrameCodeAddress().GetLoadAddress(&m_thread.GetProcess()->GetTarget());
101 
102         if (m_return_addr == LLDB_INVALID_ADDRESS)
103             return;
104 
105         Breakpoint *return_bp = m_thread.CalculateTarget()->CreateBreakpoint (m_return_addr, true).get();
106         if (return_bp != NULL)
107         {
108             return_bp->SetThreadID(m_thread.GetID());
109             m_return_bp_id = return_bp->GetID();
110             return_bp->SetBreakpointKind ("step-out");
111         }
112 
113         if (immediate_return_from_sp)
114         {
115             const SymbolContext &sc = immediate_return_from_sp->GetSymbolContext(eSymbolContextFunction);
116             if (sc.function)
117             {
118                 m_immediate_step_from_function = sc.function;
119             }
120         }
121     }
122 
123 }
124 
125 void
126 ThreadPlanStepOut::DidPush()
127 {
128     if (m_step_out_plan_sp)
129         m_thread.QueueThreadPlan(m_step_out_plan_sp, false);
130     else if (m_step_through_inline_plan_sp)
131         m_thread.QueueThreadPlan(m_step_through_inline_plan_sp, false);
132 }
133 
134 ThreadPlanStepOut::~ThreadPlanStepOut ()
135 {
136     if (m_return_bp_id != LLDB_INVALID_BREAK_ID)
137         m_thread.CalculateTarget()->RemoveBreakpointByID(m_return_bp_id);
138 }
139 
140 void
141 ThreadPlanStepOut::GetDescription (Stream *s, lldb::DescriptionLevel level)
142 {
143     if (level == lldb::eDescriptionLevelBrief)
144         s->Printf ("step out");
145     else
146     {
147         if (m_step_out_plan_sp)
148             s->Printf ("Stepping out to inlined frame so we can walk through it.");
149         else if (m_step_through_inline_plan_sp)
150             s->Printf ("Stepping out by stepping through inlined function.");
151         else
152             s->Printf ("Stepping out from address 0x%" PRIx64 " to return address 0x%" PRIx64 " using breakpoint site %d",
153                        (uint64_t)m_step_from_insn,
154                        (uint64_t)m_return_addr,
155                        m_return_bp_id);
156     }
157 }
158 
159 bool
160 ThreadPlanStepOut::ValidatePlan (Stream *error)
161 {
162     if (m_step_out_plan_sp)
163         return m_step_out_plan_sp->ValidatePlan (error);
164     else if (m_step_through_inline_plan_sp)
165         return m_step_through_inline_plan_sp->ValidatePlan (error);
166     else if (m_return_bp_id == LLDB_INVALID_BREAK_ID)
167     {
168         if (error)
169             error->PutCString("Could not create return address breakpoint.");
170         return false;
171     }
172     else
173         return true;
174 }
175 
176 bool
177 ThreadPlanStepOut::PlanExplainsStop (Event *event_ptr)
178 {
179     // If one of our child plans just finished, then we do explain the stop.
180     if (m_step_out_plan_sp)
181     {
182         if (m_step_out_plan_sp->MischiefManaged())
183         {
184             // If this one is done, then we are all done.
185             CalculateReturnValue();
186             SetPlanComplete();
187             return true;
188         }
189         else
190             return false;
191     }
192     else if (m_step_through_inline_plan_sp)
193     {
194         if (m_step_through_inline_plan_sp->MischiefManaged())
195             return true;
196         else
197             return false;
198     }
199 
200     // We don't explain signals or breakpoints (breakpoints that handle stepping in or
201     // out will be handled by a child plan.
202 
203     StopInfoSP stop_info_sp = GetPrivateStopReason();
204     if (stop_info_sp)
205     {
206         StopReason reason = stop_info_sp->GetStopReason();
207         switch (reason)
208         {
209         case eStopReasonBreakpoint:
210         {
211             // If this is OUR breakpoint, we're fine, otherwise we don't know why this happened...
212             BreakpointSiteSP site_sp (m_thread.GetProcess()->GetBreakpointSiteList().FindByID (stop_info_sp->GetValue()));
213             if (site_sp && site_sp->IsBreakpointAtThisSite (m_return_bp_id))
214             {
215                 bool done;
216 
217                 StackID frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
218 
219                 if (m_step_out_to_id == frame_zero_id)
220                     done = true;
221                 else if (m_step_out_to_id < frame_zero_id)
222                 {
223                     // Either we stepped past the breakpoint, or the stack ID calculation
224                     // was incorrect and we should probably stop.
225                     done = true;
226                 }
227                 else
228                 {
229                     if (m_immediate_step_from_id < frame_zero_id)
230                         done = true;
231                     else
232                         done = false;
233                 }
234 
235                 if (done)
236                 {
237                     CalculateReturnValue();
238                     SetPlanComplete();
239                 }
240 
241                 // If there was only one owner, then we're done.  But if we also hit some
242                 // user breakpoint on our way out, we should mark ourselves as done, but
243                 // also not claim to explain the stop, since it is more important to report
244                 // the user breakpoint than the step out completion.
245 
246                 if (site_sp->GetNumberOfOwners() == 1)
247                     return true;
248 
249             }
250             return false;
251         }
252         case eStopReasonWatchpoint:
253         case eStopReasonSignal:
254         case eStopReasonException:
255         case eStopReasonExec:
256         case eStopReasonThreadExiting:
257             return false;
258 
259         default:
260             return true;
261         }
262     }
263     return true;
264 }
265 
266 bool
267 ThreadPlanStepOut::ShouldStop (Event *event_ptr)
268 {
269         if (IsPlanComplete())
270             return true;
271 
272         bool done;
273 
274         StackID frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
275         if (frame_zero_id < m_step_out_to_id)
276             done = false;
277         else
278             done = true;
279 
280         if (done)
281         {
282             CalculateReturnValue();
283             SetPlanComplete();
284             return true;
285         }
286         else
287         {
288             if (m_step_out_plan_sp)
289             {
290                 if (m_step_out_plan_sp->MischiefManaged())
291                 {
292                     // Now step through the inlined stack we are in:
293                     if (QueueInlinedStepPlan(true))
294                     {
295                         return false;
296                     }
297                     else
298                     {
299                         CalculateReturnValue();
300                         SetPlanComplete ();
301                         return true;
302                     }
303                 }
304                 else
305                     return m_step_out_plan_sp->ShouldStop(event_ptr);
306             }
307             else if (m_step_through_inline_plan_sp)
308             {
309                 if (m_step_through_inline_plan_sp->MischiefManaged())
310                 {
311                     // We don't calculate the return value here because we don't know how to.
312                     // But in case we had a return value sitting around from our process in
313                     // getting here, let's clear it out.
314                     m_return_valobj_sp.reset();
315                     SetPlanComplete();
316                     return true;
317                 }
318                 else
319                     return m_step_through_inline_plan_sp->ShouldStop(event_ptr);
320             }
321             else
322                 return false;
323         }
324 }
325 
326 bool
327 ThreadPlanStepOut::StopOthers ()
328 {
329     return m_stop_others;
330 }
331 
332 StateType
333 ThreadPlanStepOut::GetPlanRunState ()
334 {
335     return eStateRunning;
336 }
337 
338 bool
339 ThreadPlanStepOut::WillResume (StateType resume_state, bool current_plan)
340 {
341     ThreadPlan::WillResume (resume_state, current_plan);
342     if (m_step_out_plan_sp || m_step_through_inline_plan_sp)
343         return true;
344 
345     if (m_return_bp_id == LLDB_INVALID_BREAK_ID)
346         return false;
347 
348     if (current_plan)
349     {
350         Breakpoint *return_bp = m_thread.CalculateTarget()->GetBreakpointByID(m_return_bp_id).get();
351         if (return_bp != NULL)
352             return_bp->SetEnabled (true);
353     }
354     return true;
355 }
356 
357 bool
358 ThreadPlanStepOut::WillStop ()
359 {
360     if (m_return_bp_id != LLDB_INVALID_BREAK_ID)
361     {
362         Breakpoint *return_bp = m_thread.CalculateTarget()->GetBreakpointByID(m_return_bp_id).get();
363         if (return_bp != NULL)
364             return_bp->SetEnabled (false);
365     }
366 
367     return true;
368 }
369 
370 bool
371 ThreadPlanStepOut::MischiefManaged ()
372 {
373     if (IsPlanComplete())
374     {
375         // Did I reach my breakpoint?  If so I'm done.
376         //
377         // I also check the stack depth, since if we've blown past the breakpoint for some
378         // reason and we're now stopping for some other reason altogether, then we're done
379         // with this step out operation.
380 
381         Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
382         if (log)
383             log->Printf("Completed step out plan.");
384         if (m_return_bp_id != LLDB_INVALID_BREAK_ID)
385         {
386             m_thread.CalculateTarget()->RemoveBreakpointByID (m_return_bp_id);
387             m_return_bp_id = LLDB_INVALID_BREAK_ID;
388         }
389 
390         ThreadPlan::MischiefManaged ();
391         return true;
392     }
393     else
394     {
395         return false;
396     }
397 }
398 
399 bool
400 ThreadPlanStepOut::QueueInlinedStepPlan (bool queue_now)
401 {
402     // Now figure out the range of this inlined block, and set up a "step through range"
403     // plan for that.  If we've been provided with a context, then use the block in that
404     // context.
405     StackFrameSP immediate_return_from_sp (m_thread.GetStackFrameAtIndex (0));
406     if (!immediate_return_from_sp)
407         return false;
408 
409     Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
410     if (log)
411     {
412         StreamString s;
413         immediate_return_from_sp->Dump(&s, true, false);
414         log->Printf("Queuing inlined frame to step past: %s.", s.GetData());
415     }
416 
417     Block *from_block = immediate_return_from_sp->GetFrameBlock();
418     if (from_block)
419     {
420         Block *inlined_block = from_block->GetContainingInlinedBlock();
421         if (inlined_block)
422         {
423             size_t num_ranges = inlined_block->GetNumRanges();
424             AddressRange inline_range;
425             if (inlined_block->GetRangeAtIndex(0, inline_range))
426             {
427                 SymbolContext inlined_sc;
428                 inlined_block->CalculateSymbolContext(&inlined_sc);
429                 inlined_sc.target_sp = GetTarget().shared_from_this();
430                 RunMode run_mode = m_stop_others ? lldb::eOnlyThisThread : lldb::eAllThreads;
431                 ThreadPlanStepOverRange *step_through_inline_plan_ptr = new ThreadPlanStepOverRange(m_thread,
432                                                                                                     inline_range,
433                                                                                                     inlined_sc,
434                                                                                                     run_mode);
435                 step_through_inline_plan_ptr->SetOkayToDiscard(true);
436                 StreamString errors;
437                 if (!step_through_inline_plan_ptr->ValidatePlan(&errors))
438                 {
439                     //FIXME: Log this failure.
440                     delete step_through_inline_plan_ptr;
441                     return false;
442                 }
443 
444                 for (size_t i = 1; i < num_ranges; i++)
445                 {
446                     if (inlined_block->GetRangeAtIndex (i, inline_range))
447                         step_through_inline_plan_ptr->AddRange (inline_range);
448                 }
449                 m_step_through_inline_plan_sp.reset (step_through_inline_plan_ptr);
450                 if (queue_now)
451                     m_thread.QueueThreadPlan (m_step_through_inline_plan_sp, false);
452                 return true;
453             }
454         }
455     }
456 
457     return false;
458 }
459 
460 void
461 ThreadPlanStepOut::CalculateReturnValue ()
462 {
463     if (m_return_valobj_sp)
464         return;
465 
466     if (m_immediate_step_from_function != NULL)
467     {
468         Type *return_type = m_immediate_step_from_function->GetType();
469         lldb::clang_type_t return_clang_type = m_immediate_step_from_function->GetReturnClangType();
470         if (return_type && return_clang_type)
471         {
472             ClangASTType ast_type (return_type->GetClangAST(), return_clang_type);
473 
474             lldb::ABISP abi_sp = m_thread.GetProcess()->GetABI();
475             if (abi_sp)
476             {
477                 m_return_valobj_sp = abi_sp->GetReturnValueObject(m_thread, ast_type);
478             }
479         }
480     }
481 }
482 
483 bool
484 ThreadPlanStepOut::IsPlanStale()
485 {
486     // If we are still lower on the stack than the frame we are returning to, then
487     // there's something for us to do.  Otherwise, we're stale.
488 
489     StackID frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
490     if (frame_zero_id < m_step_out_to_id)
491         return false;
492     else
493         return true;
494 }
495 
496