ThreadPlanStepUntil.cpp revision 344779 
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#include "lldb/Target/ThreadPlanStepUntil.h"
11
12#include "lldb/Breakpoint/Breakpoint.h"
13#include "lldb/Symbol/SymbolContextScope.h"
14#include "lldb/Target/Process.h"
15#include "lldb/Target/RegisterContext.h"
16#include "lldb/Target/StopInfo.h"
17#include "lldb/Target/Target.h"
18#include "lldb/Utility/Log.h"
19
20using namespace lldb;
21using namespace lldb_private;
22
23//----------------------------------------------------------------------
24// ThreadPlanStepUntil: Run until we reach a given line number or step out of
25// the current frame
26//----------------------------------------------------------------------
27
28ThreadPlanStepUntil::ThreadPlanStepUntil(Thread &thread,
29                                         lldb::addr_t *address_list,
30                                         size_t num_addresses, bool stop_others,
31                                         uint32_t frame_idx)
32    : ThreadPlan(ThreadPlan::eKindStepUntil, "Step until", thread,
33                 eVoteNoOpinion, eVoteNoOpinion),
34      m_step_from_insn(LLDB_INVALID_ADDRESS),
35      m_return_bp_id(LLDB_INVALID_BREAK_ID),
36      m_return_addr(LLDB_INVALID_ADDRESS), m_stepped_out(false),
37      m_should_stop(false), m_ran_analyze(false), m_explains_stop(false),
38      m_until_points(), m_stop_others(stop_others) {
39  // Stash away our "until" addresses:
40  TargetSP target_sp(m_thread.CalculateTarget());
41
42  StackFrameSP frame_sp(m_thread.GetStackFrameAtIndex(frame_idx));
43  if (frame_sp) {
44    m_step_from_insn = frame_sp->GetStackID().GetPC();
45    lldb::user_id_t thread_id = m_thread.GetID();
46
47    // Find the return address and set a breakpoint there:
48    // FIXME - can we do this more securely if we know first_insn?
49
50    StackFrameSP return_frame_sp(m_thread.GetStackFrameAtIndex(frame_idx + 1));
51    if (return_frame_sp) {
52      // TODO: add inline functionality
53      m_return_addr = return_frame_sp->GetStackID().GetPC();
54      Breakpoint *return_bp =
55          target_sp->CreateBreakpoint(m_return_addr, true, false).get();
56
57      if (return_bp != nullptr) {
58        if (return_bp->IsHardware() && !return_bp->HasResolvedLocations())
59          m_could_not_resolve_hw_bp = true;
60        return_bp->SetThreadID(thread_id);
61        m_return_bp_id = return_bp->GetID();
62        return_bp->SetBreakpointKind("until-return-backstop");
63      }
64    }
65
66    m_stack_id = frame_sp->GetStackID();
67
68    // Now set breakpoints on all our return addresses:
69    for (size_t i = 0; i < num_addresses; i++) {
70      Breakpoint *until_bp =
71          target_sp->CreateBreakpoint(address_list[i], true, false).get();
72      if (until_bp != nullptr) {
73        until_bp->SetThreadID(thread_id);
74        m_until_points[address_list[i]] = until_bp->GetID();
75        until_bp->SetBreakpointKind("until-target");
76      } else {
77        m_until_points[address_list[i]] = LLDB_INVALID_BREAK_ID;
78      }
79    }
80  }
81}
82
83ThreadPlanStepUntil::~ThreadPlanStepUntil() { Clear(); }
84
85void ThreadPlanStepUntil::Clear() {
86  TargetSP target_sp(m_thread.CalculateTarget());
87  if (target_sp) {
88    if (m_return_bp_id != LLDB_INVALID_BREAK_ID) {
89      target_sp->RemoveBreakpointByID(m_return_bp_id);
90      m_return_bp_id = LLDB_INVALID_BREAK_ID;
91    }
92
93    until_collection::iterator pos, end = m_until_points.end();
94    for (pos = m_until_points.begin(); pos != end; pos++) {
95      target_sp->RemoveBreakpointByID((*pos).second);
96    }
97  }
98  m_until_points.clear();
99  m_could_not_resolve_hw_bp = false;
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_could_not_resolve_hw_bp) {
131    if (error)
132      error->PutCString(
133          "Could not create hardware breakpoint for thread plan.");
134    return false;
135  } else if (m_return_bp_id == LLDB_INVALID_BREAK_ID) {
136    if (error)
137      error->PutCString("Could not create return breakpoint.");
138    return false;
139  } else {
140    until_collection::iterator pos, end = m_until_points.end();
141    for (pos = m_until_points.begin(); pos != end; pos++) {
142      if (!LLDB_BREAK_ID_IS_VALID((*pos).second))
143        return false;
144    }
145    return true;
146  }
147}
148
149void ThreadPlanStepUntil::AnalyzeStop() {
150  if (m_ran_analyze)
151    return;
152
153  StopInfoSP stop_info_sp = GetPrivateStopInfo();
154  m_should_stop = true;
155  m_explains_stop = false;
156
157  if (stop_info_sp) {
158    StopReason reason = stop_info_sp->GetStopReason();
159
160    if (reason == eStopReasonBreakpoint) {
161      // If this is OUR breakpoint, we're fine, otherwise we don't know why
162      // this happened...
163      BreakpointSiteSP this_site =
164          m_thread.GetProcess()->GetBreakpointSiteList().FindByID(
165              stop_info_sp->GetValue());
166      if (!this_site) {
167        m_explains_stop = false;
168        return;
169      }
170
171      if (this_site->IsBreakpointAtThisSite(m_return_bp_id)) {
172        // If we are at our "step out" breakpoint, and the stack depth has
173        // shrunk, then this is indeed our stop. If the stack depth has grown,
174        // then we've hit our step out breakpoint recursively. If we are the
175        // only breakpoint at that location, then we do explain the stop, and
176        // we'll just continue. If there was another breakpoint here, then we
177        // don't explain the stop, but we won't mark ourselves Completed,
178        // because maybe that breakpoint will continue, and then we'll finish
179        // the "until".
180        bool done;
181        StackID cur_frame_zero_id;
182
183        done = (m_stack_id < cur_frame_zero_id);
184
185        if (done) {
186          m_stepped_out = true;
187          SetPlanComplete();
188        } else
189          m_should_stop = false;
190
191        if (this_site->GetNumberOfOwners() == 1)
192          m_explains_stop = true;
193        else
194          m_explains_stop = false;
195        return;
196      } else {
197        // Check if we've hit one of our "until" breakpoints.
198        until_collection::iterator pos, end = m_until_points.end();
199        for (pos = m_until_points.begin(); pos != end; pos++) {
200          if (this_site->IsBreakpointAtThisSite((*pos).second)) {
201            // If we're at the right stack depth, then we're done.
202
203            bool done;
204            StackID frame_zero_id =
205                m_thread.GetStackFrameAtIndex(0)->GetStackID();
206
207            if (frame_zero_id == m_stack_id)
208              done = true;
209            else if (frame_zero_id < m_stack_id)
210              done = false;
211            else {
212              StackFrameSP older_frame_sp = m_thread.GetStackFrameAtIndex(1);
213
214              // But if we can't even unwind one frame we should just get out
215              // of here & stop...
216              if (older_frame_sp) {
217                const SymbolContext &older_context =
218                    older_frame_sp->GetSymbolContext(eSymbolContextEverything);
219                SymbolContext stack_context;
220                m_stack_id.GetSymbolContextScope()->CalculateSymbolContext(
221                    &stack_context);
222
223                done = (older_context == stack_context);
224              } else
225                done = false;
226            }
227
228            if (done)
229              SetPlanComplete();
230            else
231              m_should_stop = false;
232
233            // Otherwise we've hit this breakpoint recursively.  If we're the
234            // only breakpoint here, then we do explain the stop, and we'll
235            // continue. If not then we should let higher plans handle this
236            // stop.
237            if (this_site->GetNumberOfOwners() == 1)
238              m_explains_stop = true;
239            else {
240              m_should_stop = true;
241              m_explains_stop = false;
242            }
243            return;
244          }
245        }
246      }
247      // If we get here we haven't hit any of our breakpoints, so let the
248      // higher plans take care of the stop.
249      m_explains_stop = false;
250      return;
251    } else if (IsUsuallyUnexplainedStopReason(reason)) {
252      m_explains_stop = false;
253    } else {
254      m_explains_stop = true;
255    }
256  }
257}
258
259bool ThreadPlanStepUntil::DoPlanExplainsStop(Event *event_ptr) {
260  // We don't explain signals or breakpoints (breakpoints that handle stepping
261  // in or out will be handled by a child plan.
262  AnalyzeStop();
263  return m_explains_stop;
264}
265
266bool ThreadPlanStepUntil::ShouldStop(Event *event_ptr) {
267  // If we've told our self in ExplainsStop that we plan to continue, then do
268  // so here.  Otherwise, as long as this thread has stopped for a reason, we
269  // will stop.
270
271  StopInfoSP stop_info_sp = GetPrivateStopInfo();
272  if (!stop_info_sp || stop_info_sp->GetStopReason() == eStopReasonNone)
273    return false;
274
275  AnalyzeStop();
276  return m_should_stop;
277}
278
279bool ThreadPlanStepUntil::StopOthers() { return m_stop_others; }
280
281StateType ThreadPlanStepUntil::GetPlanRunState() { return eStateRunning; }
282
283bool ThreadPlanStepUntil::DoWillResume(StateType resume_state,
284                                       bool current_plan) {
285  if (current_plan) {
286    TargetSP target_sp(m_thread.CalculateTarget());
287    if (target_sp) {
288      Breakpoint *return_bp =
289          target_sp->GetBreakpointByID(m_return_bp_id).get();
290      if (return_bp != nullptr)
291        return_bp->SetEnabled(true);
292
293      until_collection::iterator pos, end = m_until_points.end();
294      for (pos = m_until_points.begin(); pos != end; pos++) {
295        Breakpoint *until_bp =
296            target_sp->GetBreakpointByID((*pos).second).get();
297        if (until_bp != nullptr)
298          until_bp->SetEnabled(true);
299      }
300    }
301  }
302
303  m_should_stop = true;
304  m_ran_analyze = false;
305  m_explains_stop = false;
306  return true;
307}
308
309bool ThreadPlanStepUntil::WillStop() {
310  TargetSP target_sp(m_thread.CalculateTarget());
311  if (target_sp) {
312    Breakpoint *return_bp = target_sp->GetBreakpointByID(m_return_bp_id).get();
313    if (return_bp != nullptr)
314      return_bp->SetEnabled(false);
315
316    until_collection::iterator pos, end = m_until_points.end();
317    for (pos = m_until_points.begin(); pos != end; pos++) {
318      Breakpoint *until_bp = target_sp->GetBreakpointByID((*pos).second).get();
319      if (until_bp != nullptr)
320        until_bp->SetEnabled(false);
321    }
322  }
323  return true;
324}
325
326bool ThreadPlanStepUntil::MischiefManaged() {
327  // I'm letting "PlanExplainsStop" do all the work, and just reporting that
328  // here.
329  bool done = false;
330  if (IsPlanComplete()) {
331    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
332    if (log)
333      log->Printf("Completed step until plan.");
334
335    Clear();
336    done = true;
337  }
338  if (done)
339    ThreadPlan::MischiefManaged();
340
341  return done;
342}
343