ThreadPlanStepUntil.cpp revision 341825 
1//===-- ThreadPlanStepUntil.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// C Includes
11// C++ Includes
12// Other libraries and framework includes
13// Project includes
14#include "lldb/Target/ThreadPlanStepUntil.h"
15
16#include "lldb/Breakpoint/Breakpoint.h"
17#include "lldb/Symbol/SymbolContextScope.h"
18#include "lldb/Target/Process.h"
19#include "lldb/Target/RegisterContext.h"
20#include "lldb/Target/StopInfo.h"
21#include "lldb/Target/Target.h"
22#include "lldb/Utility/Log.h"
23
24using namespace lldb;
25using namespace lldb_private;
26
27//----------------------------------------------------------------------
28// ThreadPlanStepUntil: Run until we reach a given line number or step out of
29// the current frame
30//----------------------------------------------------------------------
31
32ThreadPlanStepUntil::ThreadPlanStepUntil(Thread &thread,
33                                         lldb::addr_t *address_list,
34                                         size_t num_addresses, bool stop_others,
35                                         uint32_t frame_idx)
36    : ThreadPlan(ThreadPlan::eKindStepUntil, "Step until", thread,
37                 eVoteNoOpinion, eVoteNoOpinion),
38      m_step_from_insn(LLDB_INVALID_ADDRESS),
39      m_return_bp_id(LLDB_INVALID_BREAK_ID),
40      m_return_addr(LLDB_INVALID_ADDRESS), m_stepped_out(false),
41      m_should_stop(false), m_ran_analyze(false), m_explains_stop(false),
42      m_until_points(), m_stop_others(stop_others) {
43  // Stash away our "until" addresses:
44  TargetSP target_sp(m_thread.CalculateTarget());
45
46  StackFrameSP frame_sp(m_thread.GetStackFrameAtIndex(frame_idx));
47  if (frame_sp) {
48    m_step_from_insn = frame_sp->GetStackID().GetPC();
49    lldb::user_id_t thread_id = m_thread.GetID();
50
51    // Find the return address and set a breakpoint there:
52    // FIXME - can we do this more securely if we know first_insn?
53
54    StackFrameSP return_frame_sp(m_thread.GetStackFrameAtIndex(frame_idx + 1));
55    if (return_frame_sp) {
56      // TODO: add inline functionality
57      m_return_addr = return_frame_sp->GetStackID().GetPC();
58      Breakpoint *return_bp =
59          target_sp->CreateBreakpoint(m_return_addr, true, false).get();
60      if (return_bp != nullptr) {
61        return_bp->SetThreadID(thread_id);
62        m_return_bp_id = return_bp->GetID();
63        return_bp->SetBreakpointKind("until-return-backstop");
64      }
65    }
66
67    m_stack_id = frame_sp->GetStackID();
68
69    // Now set breakpoints on all our return addresses:
70    for (size_t i = 0; i < num_addresses; i++) {
71      Breakpoint *until_bp =
72          target_sp->CreateBreakpoint(address_list[i], true, false).get();
73      if (until_bp != nullptr) {
74        until_bp->SetThreadID(thread_id);
75        m_until_points[address_list[i]] = until_bp->GetID();
76        until_bp->SetBreakpointKind("until-target");
77      } else {
78        m_until_points[address_list[i]] = LLDB_INVALID_BREAK_ID;
79      }
80    }
81  }
82}
83
84ThreadPlanStepUntil::~ThreadPlanStepUntil() { Clear(); }
85
86void ThreadPlanStepUntil::Clear() {
87  TargetSP target_sp(m_thread.CalculateTarget());
88  if (target_sp) {
89    if (m_return_bp_id != LLDB_INVALID_BREAK_ID) {
90      target_sp->RemoveBreakpointByID(m_return_bp_id);
91      m_return_bp_id = LLDB_INVALID_BREAK_ID;
92    }
93
94    until_collection::iterator pos, end = m_until_points.end();
95    for (pos = m_until_points.begin(); pos != end; pos++) {
96      target_sp->RemoveBreakpointByID((*pos).second);
97    }
98  }
99  m_until_points.clear();
100}
101
102void ThreadPlanStepUntil::GetDescription(Stream *s,
103                                         lldb::DescriptionLevel level) {
104  if (level == lldb::eDescriptionLevelBrief) {
105    s->Printf("step until");
106    if (m_stepped_out)
107      s->Printf(" - stepped out");
108  } else {
109    if (m_until_points.size() == 1)
110      s->Printf("Stepping from address 0x%" PRIx64 " until we reach 0x%" PRIx64
111                " using breakpoint %d",
112                (uint64_t)m_step_from_insn,
113                (uint64_t)(*m_until_points.begin()).first,
114                (*m_until_points.begin()).second);
115    else {
116      until_collection::iterator pos, end = m_until_points.end();
117      s->Printf("Stepping from address 0x%" PRIx64 " until we reach one of:",
118                (uint64_t)m_step_from_insn);
119      for (pos = m_until_points.begin(); pos != end; pos++) {
120        s->Printf("\n\t0x%" PRIx64 " (bp: %d)", (uint64_t)(*pos).first,
121                  (*pos).second);
122      }
123    }
124    s->Printf(" stepped out address is 0x%" PRIx64 ".",
125              (uint64_t)m_return_addr);
126  }
127}
128
129bool ThreadPlanStepUntil::ValidatePlan(Stream *error) {
130  if (m_return_bp_id == LLDB_INVALID_BREAK_ID)
131    return false;
132  else {
133    until_collection::iterator pos, end = m_until_points.end();
134    for (pos = m_until_points.begin(); pos != end; pos++) {
135      if (!LLDB_BREAK_ID_IS_VALID((*pos).second))
136        return false;
137    }
138    return true;
139  }
140}
141
142void ThreadPlanStepUntil::AnalyzeStop() {
143  if (m_ran_analyze)
144    return;
145
146  StopInfoSP stop_info_sp = GetPrivateStopInfo();
147  m_should_stop = true;
148  m_explains_stop = false;
149
150  if (stop_info_sp) {
151    StopReason reason = stop_info_sp->GetStopReason();
152
153    if (reason == eStopReasonBreakpoint) {
154      // If this is OUR breakpoint, we're fine, otherwise we don't know why
155      // this happened...
156      BreakpointSiteSP this_site =
157          m_thread.GetProcess()->GetBreakpointSiteList().FindByID(
158              stop_info_sp->GetValue());
159      if (!this_site) {
160        m_explains_stop = false;
161        return;
162      }
163
164      if (this_site->IsBreakpointAtThisSite(m_return_bp_id)) {
165        // If we are at our "step out" breakpoint, and the stack depth has
166        // shrunk, then this is indeed our stop. If the stack depth has grown,
167        // then we've hit our step out breakpoint recursively. If we are the
168        // only breakpoint at that location, then we do explain the stop, and
169        // we'll just continue. If there was another breakpoint here, then we
170        // don't explain the stop, but we won't mark ourselves Completed,
171        // because maybe that breakpoint will continue, and then we'll finish
172        // the "until".
173        bool done;
174        StackID cur_frame_zero_id;
175
176        done = (m_stack_id < cur_frame_zero_id);
177
178        if (done) {
179          m_stepped_out = true;
180          SetPlanComplete();
181        } else
182          m_should_stop = false;
183
184        if (this_site->GetNumberOfOwners() == 1)
185          m_explains_stop = true;
186        else
187          m_explains_stop = false;
188        return;
189      } else {
190        // Check if we've hit one of our "until" breakpoints.
191        until_collection::iterator pos, end = m_until_points.end();
192        for (pos = m_until_points.begin(); pos != end; pos++) {
193          if (this_site->IsBreakpointAtThisSite((*pos).second)) {
194            // If we're at the right stack depth, then we're done.
195
196            bool done;
197            StackID frame_zero_id =
198                m_thread.GetStackFrameAtIndex(0)->GetStackID();
199
200            if (frame_zero_id == m_stack_id)
201              done = true;
202            else if (frame_zero_id < m_stack_id)
203              done = false;
204            else {
205              StackFrameSP older_frame_sp = m_thread.GetStackFrameAtIndex(1);
206
207              // But if we can't even unwind one frame we should just get out
208              // of here & stop...
209              if (older_frame_sp) {
210                const SymbolContext &older_context =
211                    older_frame_sp->GetSymbolContext(eSymbolContextEverything);
212                SymbolContext stack_context;
213                m_stack_id.GetSymbolContextScope()->CalculateSymbolContext(
214                    &stack_context);
215
216                done = (older_context == stack_context);
217              } else
218                done = false;
219            }
220
221            if (done)
222              SetPlanComplete();
223            else
224              m_should_stop = false;
225
226            // Otherwise we've hit this breakpoint recursively.  If we're the
227            // only breakpoint here, then we do explain the stop, and we'll
228            // continue. If not then we should let higher plans handle this
229            // stop.
230            if (this_site->GetNumberOfOwners() == 1)
231              m_explains_stop = true;
232            else {
233              m_should_stop = true;
234              m_explains_stop = false;
235            }
236            return;
237          }
238        }
239      }
240      // If we get here we haven't hit any of our breakpoints, so let the
241      // higher plans take care of the stop.
242      m_explains_stop = false;
243      return;
244    } else if (IsUsuallyUnexplainedStopReason(reason)) {
245      m_explains_stop = false;
246    } else {
247      m_explains_stop = true;
248    }
249  }
250}
251
252bool ThreadPlanStepUntil::DoPlanExplainsStop(Event *event_ptr) {
253  // We don't explain signals or breakpoints (breakpoints that handle stepping
254  // in or out will be handled by a child plan.
255  AnalyzeStop();
256  return m_explains_stop;
257}
258
259bool ThreadPlanStepUntil::ShouldStop(Event *event_ptr) {
260  // If we've told our self in ExplainsStop that we plan to continue, then do
261  // so here.  Otherwise, as long as this thread has stopped for a reason, we
262  // will stop.
263
264  StopInfoSP stop_info_sp = GetPrivateStopInfo();
265  if (!stop_info_sp || stop_info_sp->GetStopReason() == eStopReasonNone)
266    return false;
267
268  AnalyzeStop();
269  return m_should_stop;
270}
271
272bool ThreadPlanStepUntil::StopOthers() { return m_stop_others; }
273
274StateType ThreadPlanStepUntil::GetPlanRunState() { return eStateRunning; }
275
276bool ThreadPlanStepUntil::DoWillResume(StateType resume_state,
277                                       bool current_plan) {
278  if (current_plan) {
279    TargetSP target_sp(m_thread.CalculateTarget());
280    if (target_sp) {
281      Breakpoint *return_bp =
282          target_sp->GetBreakpointByID(m_return_bp_id).get();
283      if (return_bp != nullptr)
284        return_bp->SetEnabled(true);
285
286      until_collection::iterator pos, end = m_until_points.end();
287      for (pos = m_until_points.begin(); pos != end; pos++) {
288        Breakpoint *until_bp =
289            target_sp->GetBreakpointByID((*pos).second).get();
290        if (until_bp != nullptr)
291          until_bp->SetEnabled(true);
292      }
293    }
294  }
295
296  m_should_stop = true;
297  m_ran_analyze = false;
298  m_explains_stop = false;
299  return true;
300}
301
302bool ThreadPlanStepUntil::WillStop() {
303  TargetSP target_sp(m_thread.CalculateTarget());
304  if (target_sp) {
305    Breakpoint *return_bp = target_sp->GetBreakpointByID(m_return_bp_id).get();
306    if (return_bp != nullptr)
307      return_bp->SetEnabled(false);
308
309    until_collection::iterator pos, end = m_until_points.end();
310    for (pos = m_until_points.begin(); pos != end; pos++) {
311      Breakpoint *until_bp = target_sp->GetBreakpointByID((*pos).second).get();
312      if (until_bp != nullptr)
313        until_bp->SetEnabled(false);
314    }
315  }
316  return true;
317}
318
319bool ThreadPlanStepUntil::MischiefManaged() {
320  // I'm letting "PlanExplainsStop" do all the work, and just reporting that
321  // here.
322  bool done = false;
323  if (IsPlanComplete()) {
324    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
325    if (log)
326      log->Printf("Completed step until plan.");
327
328    Clear();
329    done = true;
330  }
331  if (done)
332    ThreadPlan::MischiefManaged();
333
334  return done;
335}
336