1//===-- ThreadPlanStepInRange.cpp -----------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "lldb/Target/ThreadPlanStepInRange.h"
10#include "lldb/Core/Architecture.h"
11#include "lldb/Core/Module.h"
12#include "lldb/Symbol/Function.h"
13#include "lldb/Symbol/Symbol.h"
14#include "lldb/Target/Process.h"
15#include "lldb/Target/RegisterContext.h"
16#include "lldb/Target/SectionLoadList.h"
17#include "lldb/Target/Target.h"
18#include "lldb/Target/Thread.h"
19#include "lldb/Target/ThreadPlanStepOut.h"
20#include "lldb/Target/ThreadPlanStepThrough.h"
21#include "lldb/Utility/LLDBLog.h"
22#include "lldb/Utility/Log.h"
23#include "lldb/Utility/RegularExpression.h"
24#include "lldb/Utility/Stream.h"
25
26using namespace lldb;
27using namespace lldb_private;
28
29uint32_t ThreadPlanStepInRange::s_default_flag_values =
30    ThreadPlanShouldStopHere::eStepInAvoidNoDebug;
31
32// ThreadPlanStepInRange: Step through a stack range, either stepping over or
33// into based on the value of \a type.
34
35ThreadPlanStepInRange::ThreadPlanStepInRange(
36    Thread &thread, const AddressRange &range,
37    const SymbolContext &addr_context, const char *step_into_target,
38    lldb::RunMode stop_others, LazyBool step_in_avoids_code_without_debug_info,
39    LazyBool step_out_avoids_code_without_debug_info)
40    : ThreadPlanStepRange(ThreadPlan::eKindStepInRange,
41                          "Step Range stepping in", thread, range, addr_context,
42                          stop_others),
43      ThreadPlanShouldStopHere(this), m_step_past_prologue(true),
44      m_virtual_step(false), m_step_into_target(step_into_target) {
45  SetCallbacks();
46  SetFlagsToDefault();
47  SetupAvoidNoDebug(step_in_avoids_code_without_debug_info,
48                    step_out_avoids_code_without_debug_info);
49}
50
51ThreadPlanStepInRange::~ThreadPlanStepInRange() = default;
52
53void ThreadPlanStepInRange::SetupAvoidNoDebug(
54    LazyBool step_in_avoids_code_without_debug_info,
55    LazyBool step_out_avoids_code_without_debug_info) {
56  bool avoid_nodebug = true;
57  Thread &thread = GetThread();
58  switch (step_in_avoids_code_without_debug_info) {
59  case eLazyBoolYes:
60    avoid_nodebug = true;
61    break;
62  case eLazyBoolNo:
63    avoid_nodebug = false;
64    break;
65  case eLazyBoolCalculate:
66    avoid_nodebug = thread.GetStepInAvoidsNoDebug();
67    break;
68  }
69  if (avoid_nodebug)
70    GetFlags().Set(ThreadPlanShouldStopHere::eStepInAvoidNoDebug);
71  else
72    GetFlags().Clear(ThreadPlanShouldStopHere::eStepInAvoidNoDebug);
73
74  switch (step_out_avoids_code_without_debug_info) {
75  case eLazyBoolYes:
76    avoid_nodebug = true;
77    break;
78  case eLazyBoolNo:
79    avoid_nodebug = false;
80    break;
81  case eLazyBoolCalculate:
82    avoid_nodebug = thread.GetStepOutAvoidsNoDebug();
83    break;
84  }
85  if (avoid_nodebug)
86    GetFlags().Set(ThreadPlanShouldStopHere::eStepOutAvoidNoDebug);
87  else
88    GetFlags().Clear(ThreadPlanShouldStopHere::eStepOutAvoidNoDebug);
89}
90
91void ThreadPlanStepInRange::GetDescription(Stream *s,
92                                           lldb::DescriptionLevel level) {
93
94  auto PrintFailureIfAny = [&]() {
95    if (m_status.Success())
96      return;
97    s->Printf(" failed (%s)", m_status.AsCString());
98  };
99
100  if (level == lldb::eDescriptionLevelBrief) {
101    s->Printf("step in");
102    PrintFailureIfAny();
103    return;
104  }
105
106  s->Printf("Stepping in");
107  bool printed_line_info = false;
108  if (m_addr_context.line_entry.IsValid()) {
109    s->Printf(" through line ");
110    m_addr_context.line_entry.DumpStopContext(s, false);
111    printed_line_info = true;
112  }
113
114  const char *step_into_target = m_step_into_target.AsCString();
115  if (step_into_target && step_into_target[0] != '\0')
116    s->Printf(" targeting %s", m_step_into_target.AsCString());
117
118  if (!printed_line_info || level == eDescriptionLevelVerbose) {
119    s->Printf(" using ranges:");
120    DumpRanges(s);
121  }
122
123  PrintFailureIfAny();
124
125  s->PutChar('.');
126}
127
128bool ThreadPlanStepInRange::ShouldStop(Event *event_ptr) {
129  Log *log = GetLog(LLDBLog::Step);
130
131  if (log) {
132    StreamString s;
133    DumpAddress(s.AsRawOstream(), GetThread().GetRegisterContext()->GetPC(),
134                GetTarget().GetArchitecture().GetAddressByteSize());
135    LLDB_LOGF(log, "ThreadPlanStepInRange reached %s.", s.GetData());
136  }
137
138  if (IsPlanComplete())
139    return true;
140
141  m_no_more_plans = false;
142  if (m_sub_plan_sp && m_sub_plan_sp->IsPlanComplete()) {
143    if (!m_sub_plan_sp->PlanSucceeded()) {
144      SetPlanComplete();
145      m_no_more_plans = true;
146      return true;
147    } else
148      m_sub_plan_sp.reset();
149  }
150
151  if (m_virtual_step) {
152    // If we've just completed a virtual step, all we need to do is check for a
153    // ShouldStopHere plan, and otherwise we're done.
154    // FIXME - This can be both a step in and a step out.  Probably should
155    // record which in the m_virtual_step.
156    m_sub_plan_sp =
157        CheckShouldStopHereAndQueueStepOut(eFrameCompareYounger, m_status);
158  } else {
159    // Stepping through should be done running other threads in general, since
160    // we're setting a breakpoint and continuing.  So only stop others if we
161    // are explicitly told to do so.
162
163    bool stop_others = (m_stop_others == lldb::eOnlyThisThread);
164
165    FrameComparison frame_order = CompareCurrentFrameToStartFrame();
166
167    Thread &thread = GetThread();
168    if (frame_order == eFrameCompareOlder ||
169        frame_order == eFrameCompareSameParent) {
170      // If we're in an older frame then we should stop.
171      //
172      // A caveat to this is if we think the frame is older but we're actually
173      // in a trampoline.
174      // I'm going to make the assumption that you wouldn't RETURN to a
175      // trampoline.  So if we are in a trampoline we think the frame is older
176      // because the trampoline confused the backtracer.
177      m_sub_plan_sp = thread.QueueThreadPlanForStepThrough(
178          m_stack_id, false, stop_others, m_status);
179      if (!m_sub_plan_sp) {
180        // Otherwise check the ShouldStopHere for step out:
181        m_sub_plan_sp =
182            CheckShouldStopHereAndQueueStepOut(frame_order, m_status);
183        if (log) {
184          if (m_sub_plan_sp)
185            LLDB_LOGF(log,
186                      "ShouldStopHere found plan to step out of this frame.");
187          else
188            LLDB_LOGF(log, "ShouldStopHere no plan to step out of this frame.");
189        }
190      } else if (log) {
191        LLDB_LOGF(
192            log, "Thought I stepped out, but in fact arrived at a trampoline.");
193      }
194    } else if (frame_order == eFrameCompareEqual && InSymbol()) {
195      // If we are not in a place we should step through, we're done. One
196      // tricky bit here is that some stubs don't push a frame, so we have to
197      // check both the case of a frame that is younger, or the same as this
198      // frame. However, if the frame is the same, and we are still in the
199      // symbol we started in, the we don't need to do this.  This first check
200      // isn't strictly necessary, but it is more efficient.
201
202      // If we're still in the range, keep going, either by running to the next
203      // branch breakpoint, or by stepping.
204      if (InRange()) {
205        SetNextBranchBreakpoint();
206        return false;
207      }
208
209      SetPlanComplete();
210      m_no_more_plans = true;
211      return true;
212    }
213
214    // If we get to this point, we're not going to use a previously set "next
215    // branch" breakpoint, so delete it:
216    ClearNextBranchBreakpoint();
217
218    // We may have set the plan up above in the FrameIsOlder section:
219
220    if (!m_sub_plan_sp)
221      m_sub_plan_sp = thread.QueueThreadPlanForStepThrough(
222          m_stack_id, false, stop_others, m_status);
223
224    if (log) {
225      if (m_sub_plan_sp)
226        LLDB_LOGF(log, "Found a step through plan: %s",
227                  m_sub_plan_sp->GetName());
228      else
229        LLDB_LOGF(log, "No step through plan found.");
230    }
231
232    // If not, give the "should_stop" callback a chance to push a plan to get
233    // us out of here. But only do that if we actually have stepped in.
234    if (!m_sub_plan_sp && frame_order == eFrameCompareYounger)
235      m_sub_plan_sp = CheckShouldStopHereAndQueueStepOut(frame_order, m_status);
236
237    // If we've stepped in and we are going to stop here, check to see if we
238    // were asked to run past the prologue, and if so do that.
239
240    if (!m_sub_plan_sp && frame_order == eFrameCompareYounger &&
241        m_step_past_prologue) {
242      lldb::StackFrameSP curr_frame = thread.GetStackFrameAtIndex(0);
243      if (curr_frame) {
244        size_t bytes_to_skip = 0;
245        lldb::addr_t curr_addr = thread.GetRegisterContext()->GetPC();
246        Address func_start_address;
247
248        SymbolContext sc = curr_frame->GetSymbolContext(eSymbolContextFunction |
249                                                        eSymbolContextSymbol);
250
251        if (sc.function) {
252          func_start_address = sc.function->GetAddressRange().GetBaseAddress();
253          if (curr_addr == func_start_address.GetLoadAddress(&GetTarget()))
254            bytes_to_skip = sc.function->GetPrologueByteSize();
255        } else if (sc.symbol) {
256          func_start_address = sc.symbol->GetAddress();
257          if (curr_addr == func_start_address.GetLoadAddress(&GetTarget()))
258            bytes_to_skip = sc.symbol->GetPrologueByteSize();
259        }
260
261        if (bytes_to_skip == 0 && sc.symbol) {
262          const Architecture *arch = GetTarget().GetArchitecturePlugin();
263          if (arch) {
264            Address curr_sec_addr;
265            GetTarget().GetSectionLoadList().ResolveLoadAddress(curr_addr,
266                                                                curr_sec_addr);
267            bytes_to_skip = arch->GetBytesToSkip(*sc.symbol, curr_sec_addr);
268          }
269        }
270
271        if (bytes_to_skip != 0) {
272          func_start_address.Slide(bytes_to_skip);
273          log = GetLog(LLDBLog::Step);
274          LLDB_LOGF(log, "Pushing past prologue ");
275
276          m_sub_plan_sp = thread.QueueThreadPlanForRunToAddress(
277              false, func_start_address, true, m_status);
278        }
279      }
280    }
281  }
282
283  if (!m_sub_plan_sp) {
284    m_no_more_plans = true;
285    SetPlanComplete();
286    return true;
287  } else {
288    m_no_more_plans = false;
289    m_sub_plan_sp->SetPrivate(true);
290    return false;
291  }
292}
293
294void ThreadPlanStepInRange::SetAvoidRegexp(const char *name) {
295  if (m_avoid_regexp_up)
296    *m_avoid_regexp_up = RegularExpression(name);
297  else
298    m_avoid_regexp_up = std::make_unique<RegularExpression>(name);
299}
300
301void ThreadPlanStepInRange::SetDefaultFlagValue(uint32_t new_value) {
302  // TODO: Should we test this for sanity?
303  ThreadPlanStepInRange::s_default_flag_values = new_value;
304}
305
306bool ThreadPlanStepInRange::FrameMatchesAvoidCriteria() {
307  StackFrame *frame = GetThread().GetStackFrameAtIndex(0).get();
308
309  // Check the library list first, as that's cheapest:
310  bool libraries_say_avoid = false;
311
312  FileSpecList libraries_to_avoid(GetThread().GetLibrariesToAvoid());
313  size_t num_libraries = libraries_to_avoid.GetSize();
314  if (num_libraries > 0) {
315    SymbolContext sc(frame->GetSymbolContext(eSymbolContextModule));
316    FileSpec frame_library(sc.module_sp->GetFileSpec());
317
318    if (frame_library) {
319      for (size_t i = 0; i < num_libraries; i++) {
320        const FileSpec &file_spec(libraries_to_avoid.GetFileSpecAtIndex(i));
321        if (FileSpec::Match(file_spec, frame_library)) {
322          libraries_say_avoid = true;
323          break;
324        }
325      }
326    }
327  }
328  if (libraries_say_avoid)
329    return true;
330
331  const RegularExpression *avoid_regexp_to_use = m_avoid_regexp_up.get();
332  if (avoid_regexp_to_use == nullptr)
333    avoid_regexp_to_use = GetThread().GetSymbolsToAvoidRegexp();
334
335  if (avoid_regexp_to_use != nullptr) {
336    SymbolContext sc = frame->GetSymbolContext(
337        eSymbolContextFunction | eSymbolContextBlock | eSymbolContextSymbol);
338    if (sc.symbol != nullptr) {
339      const char *frame_function_name =
340          sc.GetFunctionName(Mangled::ePreferDemangledWithoutArguments)
341              .GetCString();
342      if (frame_function_name) {
343        bool return_value = avoid_regexp_to_use->Execute(frame_function_name);
344        if (return_value) {
345          LLDB_LOGF(GetLog(LLDBLog::Step),
346                    "Stepping out of function \"%s\" because it matches the "
347                    "avoid regexp \"%s\".",
348                    frame_function_name,
349                    avoid_regexp_to_use->GetText().str().c_str());
350        }
351        return return_value;
352      }
353    }
354  }
355  return false;
356}
357
358bool ThreadPlanStepInRange::DefaultShouldStopHereCallback(
359    ThreadPlan *current_plan, Flags &flags, FrameComparison operation,
360    Status &status, void *baton) {
361  bool should_stop_here = true;
362  StackFrame *frame = current_plan->GetThread().GetStackFrameAtIndex(0).get();
363  Log *log = GetLog(LLDBLog::Step);
364
365  // First see if the ThreadPlanShouldStopHere default implementation thinks we
366  // should get out of here:
367  should_stop_here = ThreadPlanShouldStopHere::DefaultShouldStopHereCallback(
368      current_plan, flags, operation, status, baton);
369  if (!should_stop_here)
370    return false;
371
372  if (should_stop_here && current_plan->GetKind() == eKindStepInRange &&
373      operation == eFrameCompareYounger) {
374    ThreadPlanStepInRange *step_in_range_plan =
375        static_cast<ThreadPlanStepInRange *>(current_plan);
376    if (step_in_range_plan->m_step_into_target) {
377      SymbolContext sc = frame->GetSymbolContext(
378          eSymbolContextFunction | eSymbolContextBlock | eSymbolContextSymbol);
379      if (sc.symbol != nullptr) {
380        // First try an exact match, since that's cheap with ConstStrings.
381        // Then do a strstr compare.
382        if (step_in_range_plan->m_step_into_target == sc.GetFunctionName()) {
383          should_stop_here = true;
384        } else {
385          const char *target_name =
386              step_in_range_plan->m_step_into_target.AsCString();
387          const char *function_name = sc.GetFunctionName().AsCString();
388
389          if (function_name == nullptr)
390            should_stop_here = false;
391          else if (strstr(function_name, target_name) == nullptr)
392            should_stop_here = false;
393        }
394        if (log && !should_stop_here)
395          LLDB_LOGF(log,
396                    "Stepping out of frame %s which did not match step into "
397                    "target %s.",
398                    sc.GetFunctionName().AsCString(),
399                    step_in_range_plan->m_step_into_target.AsCString());
400      }
401    }
402
403    if (should_stop_here) {
404      ThreadPlanStepInRange *step_in_range_plan =
405          static_cast<ThreadPlanStepInRange *>(current_plan);
406      // Don't log the should_step_out here, it's easier to do it in
407      // FrameMatchesAvoidCriteria.
408      should_stop_here = !step_in_range_plan->FrameMatchesAvoidCriteria();
409    }
410  }
411
412  return should_stop_here;
413}
414
415bool ThreadPlanStepInRange::DoPlanExplainsStop(Event *event_ptr) {
416  // We always explain a stop.  Either we've just done a single step, in which
417  // case we'll do our ordinary processing, or we stopped for some reason that
418  // isn't handled by our sub-plans, in which case we want to just stop right
419  // away. In general, we don't want to mark the plan as complete for
420  // unexplained stops. For instance, if you step in to some code with no debug
421  // info, so you step out and in the course of that hit a breakpoint, then you
422  // want to stop & show the user the breakpoint, but not unship the step in
423  // plan, since you still may want to complete that plan when you continue.
424  // This is particularly true when doing "step in to target function."
425  // stepping.
426  //
427  // The only variation is that if we are doing "step by running to next
428  // branch" in which case if we hit our branch breakpoint we don't set the
429  // plan to complete.
430
431  bool return_value = false;
432
433  if (m_virtual_step) {
434    return_value = true;
435  } else {
436    StopInfoSP stop_info_sp = GetPrivateStopInfo();
437    if (stop_info_sp) {
438      StopReason reason = stop_info_sp->GetStopReason();
439
440      if (reason == eStopReasonBreakpoint) {
441        if (NextRangeBreakpointExplainsStop(stop_info_sp)) {
442          return_value = true;
443        }
444      } else if (IsUsuallyUnexplainedStopReason(reason)) {
445        Log *log = GetLog(LLDBLog::Step);
446        if (log)
447          log->PutCString("ThreadPlanStepInRange got asked if it explains the "
448                          "stop for some reason other than step.");
449        return_value = false;
450      } else {
451        return_value = true;
452      }
453    } else
454      return_value = true;
455  }
456
457  return return_value;
458}
459
460bool ThreadPlanStepInRange::DoWillResume(lldb::StateType resume_state,
461                                         bool current_plan) {
462  m_virtual_step = false;
463  if (resume_state == eStateStepping && current_plan) {
464    Thread &thread = GetThread();
465    // See if we are about to step over a virtual inlined call.
466    bool step_without_resume = thread.DecrementCurrentInlinedDepth();
467    if (step_without_resume) {
468      Log *log = GetLog(LLDBLog::Step);
469      LLDB_LOGF(log,
470                "ThreadPlanStepInRange::DoWillResume: returning false, "
471                "inline_depth: %d",
472                thread.GetCurrentInlinedDepth());
473      SetStopInfo(StopInfo::CreateStopReasonToTrace(thread));
474
475      // FIXME: Maybe it would be better to create a InlineStep stop reason, but
476      // then
477      // the whole rest of the world would have to handle that stop reason.
478      m_virtual_step = true;
479    }
480    return !step_without_resume;
481  }
482  return true;
483}
484
485bool ThreadPlanStepInRange::IsVirtualStep() { return m_virtual_step; }
486