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
30using namespace lldb;
31using namespace lldb_private;
32
33//----------------------------------------------------------------------
34// ThreadPlanStepOut: Step out of the current frame
35//----------------------------------------------------------------------
36ThreadPlanStepOut::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
125void
126ThreadPlanStepOut::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
134ThreadPlanStepOut::~ThreadPlanStepOut ()
135{
136    if (m_return_bp_id != LLDB_INVALID_BREAK_ID)
137        m_thread.CalculateTarget()->RemoveBreakpointByID(m_return_bp_id);
138}
139
140void
141ThreadPlanStepOut::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
159bool
160ThreadPlanStepOut::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
176bool
177ThreadPlanStepOut::DoPlanExplainsStop (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 = GetPrivateStopInfo ();
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
266bool
267ThreadPlanStepOut::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
326bool
327ThreadPlanStepOut::StopOthers ()
328{
329    return m_stop_others;
330}
331
332StateType
333ThreadPlanStepOut::GetPlanRunState ()
334{
335    return eStateRunning;
336}
337
338bool
339ThreadPlanStepOut::DoWillResume (StateType resume_state, bool current_plan)
340{
341    if (m_step_out_plan_sp || m_step_through_inline_plan_sp)
342        return true;
343
344    if (m_return_bp_id == LLDB_INVALID_BREAK_ID)
345        return false;
346
347    if (current_plan)
348    {
349        Breakpoint *return_bp = m_thread.CalculateTarget()->GetBreakpointByID(m_return_bp_id).get();
350        if (return_bp != NULL)
351            return_bp->SetEnabled (true);
352    }
353    return true;
354}
355
356bool
357ThreadPlanStepOut::WillStop ()
358{
359    if (m_return_bp_id != LLDB_INVALID_BREAK_ID)
360    {
361        Breakpoint *return_bp = m_thread.CalculateTarget()->GetBreakpointByID(m_return_bp_id).get();
362        if (return_bp != NULL)
363            return_bp->SetEnabled (false);
364    }
365
366    return true;
367}
368
369bool
370ThreadPlanStepOut::MischiefManaged ()
371{
372    if (IsPlanComplete())
373    {
374        // Did I reach my breakpoint?  If so I'm done.
375        //
376        // I also check the stack depth, since if we've blown past the breakpoint for some
377        // reason and we're now stopping for some other reason altogether, then we're done
378        // with this step out operation.
379
380        Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
381        if (log)
382            log->Printf("Completed step out plan.");
383        if (m_return_bp_id != LLDB_INVALID_BREAK_ID)
384        {
385            m_thread.CalculateTarget()->RemoveBreakpointByID (m_return_bp_id);
386            m_return_bp_id = LLDB_INVALID_BREAK_ID;
387        }
388
389        ThreadPlan::MischiefManaged ();
390        return true;
391    }
392    else
393    {
394        return false;
395    }
396}
397
398bool
399ThreadPlanStepOut::QueueInlinedStepPlan (bool queue_now)
400{
401    // Now figure out the range of this inlined block, and set up a "step through range"
402    // plan for that.  If we've been provided with a context, then use the block in that
403    // context.
404    StackFrameSP immediate_return_from_sp (m_thread.GetStackFrameAtIndex (0));
405    if (!immediate_return_from_sp)
406        return false;
407
408    Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
409    if (log)
410    {
411        StreamString s;
412        immediate_return_from_sp->Dump(&s, true, false);
413        log->Printf("Queuing inlined frame to step past: %s.", s.GetData());
414    }
415
416    Block *from_block = immediate_return_from_sp->GetFrameBlock();
417    if (from_block)
418    {
419        Block *inlined_block = from_block->GetContainingInlinedBlock();
420        if (inlined_block)
421        {
422            size_t num_ranges = inlined_block->GetNumRanges();
423            AddressRange inline_range;
424            if (inlined_block->GetRangeAtIndex(0, inline_range))
425            {
426                SymbolContext inlined_sc;
427                inlined_block->CalculateSymbolContext(&inlined_sc);
428                inlined_sc.target_sp = GetTarget().shared_from_this();
429                RunMode run_mode = m_stop_others ? lldb::eOnlyThisThread : lldb::eAllThreads;
430                ThreadPlanStepOverRange *step_through_inline_plan_ptr = new ThreadPlanStepOverRange(m_thread,
431                                                                                                    inline_range,
432                                                                                                    inlined_sc,
433                                                                                                    run_mode);
434                step_through_inline_plan_ptr->SetOkayToDiscard(true);
435                StreamString errors;
436                if (!step_through_inline_plan_ptr->ValidatePlan(&errors))
437                {
438                    //FIXME: Log this failure.
439                    delete step_through_inline_plan_ptr;
440                    return false;
441                }
442
443                for (size_t i = 1; i < num_ranges; i++)
444                {
445                    if (inlined_block->GetRangeAtIndex (i, inline_range))
446                        step_through_inline_plan_ptr->AddRange (inline_range);
447                }
448                m_step_through_inline_plan_sp.reset (step_through_inline_plan_ptr);
449                if (queue_now)
450                    m_thread.QueueThreadPlan (m_step_through_inline_plan_sp, false);
451                return true;
452            }
453        }
454    }
455
456    return false;
457}
458
459void
460ThreadPlanStepOut::CalculateReturnValue ()
461{
462    if (m_return_valobj_sp)
463        return;
464
465    if (m_immediate_step_from_function != NULL)
466    {
467        ClangASTType return_clang_type = m_immediate_step_from_function->GetClangType().GetFunctionReturnType();
468        if (return_clang_type)
469        {
470            lldb::ABISP abi_sp = m_thread.GetProcess()->GetABI();
471            if (abi_sp)
472                m_return_valobj_sp = abi_sp->GetReturnValueObject(m_thread, return_clang_type);
473        }
474    }
475}
476
477bool
478ThreadPlanStepOut::IsPlanStale()
479{
480    // If we are still lower on the stack than the frame we are returning to, then
481    // there's something for us to do.  Otherwise, we're stale.
482
483    StackID frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
484    if (frame_zero_id < m_step_out_to_id)
485        return false;
486    else
487        return true;
488}
489
490