1//===-- ThreadPlanStepOverRange.cpp -----------------------------*- C++ -*-===//
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/ThreadPlanStepOverRange.h"
10#include "lldb/Symbol/Block.h"
11#include "lldb/Symbol/CompileUnit.h"
12#include "lldb/Symbol/Function.h"
13#include "lldb/Symbol/LineTable.h"
14#include "lldb/Target/Process.h"
15#include "lldb/Target/RegisterContext.h"
16#include "lldb/Target/Target.h"
17#include "lldb/Target/Thread.h"
18#include "lldb/Target/ThreadPlanStepOut.h"
19#include "lldb/Target/ThreadPlanStepThrough.h"
20#include "lldb/Utility/Log.h"
21#include "lldb/Utility/Stream.h"
22
23using namespace lldb_private;
24using namespace lldb;
25
26uint32_t ThreadPlanStepOverRange::s_default_flag_values = 0;
27
28// ThreadPlanStepOverRange: Step through a stack range, either stepping over or
29// into based on the value of \a type.
30
31ThreadPlanStepOverRange::ThreadPlanStepOverRange(
32    Thread &thread, const AddressRange &range,
33    const SymbolContext &addr_context, lldb::RunMode stop_others,
34    LazyBool step_out_avoids_code_without_debug_info)
35    : ThreadPlanStepRange(ThreadPlan::eKindStepOverRange,
36                          "Step range stepping over", thread, range,
37                          addr_context, stop_others),
38      ThreadPlanShouldStopHere(this), m_first_resume(true) {
39  SetFlagsToDefault();
40  SetupAvoidNoDebug(step_out_avoids_code_without_debug_info);
41}
42
43ThreadPlanStepOverRange::~ThreadPlanStepOverRange() = default;
44
45void ThreadPlanStepOverRange::GetDescription(Stream *s,
46                                             lldb::DescriptionLevel level) {
47  auto PrintFailureIfAny = [&]() {
48    if (m_status.Success())
49      return;
50    s->Printf(" failed (%s)", m_status.AsCString());
51  };
52
53  if (level == lldb::eDescriptionLevelBrief) {
54    s->Printf("step over");
55    PrintFailureIfAny();
56    return;
57  }
58
59  s->Printf("Stepping over");
60  bool printed_line_info = false;
61  if (m_addr_context.line_entry.IsValid()) {
62    s->Printf(" line ");
63    m_addr_context.line_entry.DumpStopContext(s, false);
64    printed_line_info = true;
65  }
66
67  if (!printed_line_info || level == eDescriptionLevelVerbose) {
68    s->Printf(" using ranges: ");
69    DumpRanges(s);
70  }
71
72  PrintFailureIfAny();
73
74  s->PutChar('.');
75}
76
77void ThreadPlanStepOverRange::SetupAvoidNoDebug(
78    LazyBool step_out_avoids_code_without_debug_info) {
79  bool avoid_nodebug = true;
80  switch (step_out_avoids_code_without_debug_info) {
81  case eLazyBoolYes:
82    avoid_nodebug = true;
83    break;
84  case eLazyBoolNo:
85    avoid_nodebug = false;
86    break;
87  case eLazyBoolCalculate:
88    avoid_nodebug = m_thread.GetStepOutAvoidsNoDebug();
89    break;
90  }
91  if (avoid_nodebug)
92    GetFlags().Set(ThreadPlanShouldStopHere::eStepOutAvoidNoDebug);
93  else
94    GetFlags().Clear(ThreadPlanShouldStopHere::eStepOutAvoidNoDebug);
95  // Step Over plans should always avoid no-debug on step in.  Seems like you
96  // shouldn't have to say this, but a tail call looks more like a step in that
97  // a step out, so we want to catch this case.
98  GetFlags().Set(ThreadPlanShouldStopHere::eStepInAvoidNoDebug);
99}
100
101bool ThreadPlanStepOverRange::IsEquivalentContext(
102    const SymbolContext &context) {
103  // Match as much as is specified in the m_addr_context: This is a fairly
104  // loose sanity check.  Note, sometimes the target doesn't get filled in so I
105  // left out the target check.  And sometimes the module comes in as the .o
106  // file from the inlined range, so I left that out too...
107  if (m_addr_context.comp_unit) {
108    if (m_addr_context.comp_unit != context.comp_unit)
109      return false;
110    if (m_addr_context.function) {
111      if (m_addr_context.function != context.function)
112        return false;
113      // It is okay to return to a different block of a straight function, we
114      // only have to be more careful if returning from one inlined block to
115      // another.
116      if (m_addr_context.block->GetInlinedFunctionInfo() == nullptr &&
117          context.block->GetInlinedFunctionInfo() == nullptr)
118        return true;
119      return m_addr_context.block == context.block;
120    }
121  }
122  // Fall back to symbol if we have no decision from comp_unit/function/block.
123  return m_addr_context.symbol && m_addr_context.symbol == context.symbol;
124}
125
126bool ThreadPlanStepOverRange::ShouldStop(Event *event_ptr) {
127  Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
128
129  if (log) {
130    StreamString s;
131    DumpAddress(
132        s.AsRawOstream(), m_thread.GetRegisterContext()->GetPC(),
133        m_thread.CalculateTarget()->GetArchitecture().GetAddressByteSize());
134    LLDB_LOGF(log, "ThreadPlanStepOverRange reached %s.", s.GetData());
135  }
136
137  // If we're out of the range but in the same frame or in our caller's frame
138  // then we should stop. When stepping out we only stop others if we are
139  // forcing running one thread.
140  bool stop_others = (m_stop_others == lldb::eOnlyThisThread);
141  ThreadPlanSP new_plan_sp;
142  FrameComparison frame_order = CompareCurrentFrameToStartFrame();
143
144  if (frame_order == eFrameCompareOlder) {
145    // If we're in an older frame then we should stop.
146    //
147    // A caveat to this is if we think the frame is older but we're actually in
148    // a trampoline.
149    // I'm going to make the assumption that you wouldn't RETURN to a
150    // trampoline.  So if we are in a trampoline we think the frame is older
151    // because the trampoline confused the backtracer. As below, we step
152    // through first, and then try to figure out how to get back out again.
153
154    new_plan_sp = m_thread.QueueThreadPlanForStepThrough(m_stack_id, false,
155                                                         stop_others, m_status);
156
157    if (new_plan_sp && log)
158      LLDB_LOGF(log,
159                "Thought I stepped out, but in fact arrived at a trampoline.");
160  } else if (frame_order == eFrameCompareYounger) {
161    // Make sure we really are in a new frame.  Do that by unwinding and seeing
162    // if the start function really is our start function...
163    for (uint32_t i = 1;; ++i) {
164      StackFrameSP older_frame_sp = m_thread.GetStackFrameAtIndex(i);
165      if (!older_frame_sp) {
166        // We can't unwind the next frame we should just get out of here &
167        // stop...
168        break;
169      }
170
171      const SymbolContext &older_context =
172          older_frame_sp->GetSymbolContext(eSymbolContextEverything);
173      if (IsEquivalentContext(older_context)) {
174        new_plan_sp = m_thread.QueueThreadPlanForStepOutNoShouldStop(
175            false, nullptr, true, stop_others, eVoteNo, eVoteNoOpinion, 0,
176            m_status, true);
177        break;
178      } else {
179        new_plan_sp = m_thread.QueueThreadPlanForStepThrough(
180            m_stack_id, false, stop_others, m_status);
181        // If we found a way through, then we should stop recursing.
182        if (new_plan_sp)
183          break;
184      }
185    }
186  } else {
187    // If we're still in the range, keep going.
188    if (InRange()) {
189      SetNextBranchBreakpoint();
190      return false;
191    }
192
193    if (!InSymbol()) {
194      // This one is a little tricky.  Sometimes we may be in a stub or
195      // something similar, in which case we need to get out of there.  But if
196      // we are in a stub then it's likely going to be hard to get out from
197      // here.  It is probably easiest to step into the stub, and then it will
198      // be straight-forward to step out.
199      new_plan_sp = m_thread.QueueThreadPlanForStepThrough(
200          m_stack_id, false, stop_others, m_status);
201    } else {
202      // The current clang (at least through 424) doesn't always get the
203      // address range for the DW_TAG_inlined_subroutines right, so that when
204      // you leave the inlined range the line table says you are still in the
205      // source file of the inlining function.  This is bad, because now you
206      // are missing the stack frame for the function containing the inlining,
207      // and if you sensibly do "finish" to get out of this function you will
208      // instead exit the containing function. To work around this, we check
209      // whether we are still in the source file we started in, and if not
210      // assume it is an error, and push a plan to get us out of this line and
211      // back to the containing file.
212
213      if (m_addr_context.line_entry.IsValid()) {
214        SymbolContext sc;
215        StackFrameSP frame_sp = m_thread.GetStackFrameAtIndex(0);
216        sc = frame_sp->GetSymbolContext(eSymbolContextEverything);
217        if (sc.line_entry.IsValid()) {
218          if (sc.line_entry.original_file !=
219                  m_addr_context.line_entry.original_file &&
220              sc.comp_unit == m_addr_context.comp_unit &&
221              sc.function == m_addr_context.function) {
222            // Okay, find the next occurrence of this file in the line table:
223            LineTable *line_table = m_addr_context.comp_unit->GetLineTable();
224            if (line_table) {
225              Address cur_address = frame_sp->GetFrameCodeAddress();
226              uint32_t entry_idx;
227              LineEntry line_entry;
228              if (line_table->FindLineEntryByAddress(cur_address, line_entry,
229                                                     &entry_idx)) {
230                LineEntry next_line_entry;
231                bool step_past_remaining_inline = false;
232                if (entry_idx > 0) {
233                  // We require the previous line entry and the current line
234                  // entry come from the same file. The other requirement is
235                  // that the previous line table entry be part of an inlined
236                  // block, we don't want to step past cases where people have
237                  // inlined some code fragment by using #include <source-
238                  // fragment.c> directly.
239                  LineEntry prev_line_entry;
240                  if (line_table->GetLineEntryAtIndex(entry_idx - 1,
241                                                      prev_line_entry) &&
242                      prev_line_entry.original_file ==
243                          line_entry.original_file) {
244                    SymbolContext prev_sc;
245                    Address prev_address =
246                        prev_line_entry.range.GetBaseAddress();
247                    prev_address.CalculateSymbolContext(&prev_sc);
248                    if (prev_sc.block) {
249                      Block *inlined_block =
250                          prev_sc.block->GetContainingInlinedBlock();
251                      if (inlined_block) {
252                        AddressRange inline_range;
253                        inlined_block->GetRangeContainingAddress(prev_address,
254                                                                 inline_range);
255                        if (!inline_range.ContainsFileAddress(cur_address)) {
256
257                          step_past_remaining_inline = true;
258                        }
259                      }
260                    }
261                  }
262                }
263
264                if (step_past_remaining_inline) {
265                  uint32_t look_ahead_step = 1;
266                  while (line_table->GetLineEntryAtIndex(
267                      entry_idx + look_ahead_step, next_line_entry)) {
268                    // Make sure we haven't wandered out of the function we
269                    // started from...
270                    Address next_line_address =
271                        next_line_entry.range.GetBaseAddress();
272                    Function *next_line_function =
273                        next_line_address.CalculateSymbolContextFunction();
274                    if (next_line_function != m_addr_context.function)
275                      break;
276
277                    if (next_line_entry.original_file ==
278                        m_addr_context.line_entry.original_file) {
279                      const bool abort_other_plans = false;
280                      const RunMode stop_other_threads = RunMode::eAllThreads;
281                      lldb::addr_t cur_pc = m_thread.GetStackFrameAtIndex(0)
282                                                ->GetRegisterContext()
283                                                ->GetPC();
284                      AddressRange step_range(
285                          cur_pc,
286                          next_line_address.GetLoadAddress(&GetTarget()) -
287                              cur_pc);
288
289                      new_plan_sp = m_thread.QueueThreadPlanForStepOverRange(
290                          abort_other_plans, step_range, sc, stop_other_threads,
291                          m_status);
292                      break;
293                    }
294                    look_ahead_step++;
295                  }
296                }
297              }
298            }
299          }
300        }
301      }
302    }
303  }
304
305  // If we get to this point, we're not going to use a previously set "next
306  // branch" breakpoint, so delete it:
307  ClearNextBranchBreakpoint();
308
309  // If we haven't figured out something to do yet, then ask the ShouldStopHere
310  // callback:
311  if (!new_plan_sp) {
312    new_plan_sp = CheckShouldStopHereAndQueueStepOut(frame_order, m_status);
313  }
314
315  if (!new_plan_sp)
316    m_no_more_plans = true;
317  else {
318    // Any new plan will be an implementation plan, so mark it private:
319    new_plan_sp->SetPrivate(true);
320    m_no_more_plans = false;
321  }
322
323  if (!new_plan_sp) {
324    // For efficiencies sake, we know we're done here so we don't have to do
325    // this calculation again in MischiefManaged.
326    SetPlanComplete(m_status.Success());
327    return true;
328  } else
329    return false;
330}
331
332bool ThreadPlanStepOverRange::DoPlanExplainsStop(Event *event_ptr) {
333  // For crashes, breakpoint hits, signals, etc, let the base plan (or some
334  // plan above us) handle the stop.  That way the user can see the stop, step
335  // around, and then when they are done, continue and have their step
336  // complete.  The exception is if we've hit our "run to next branch"
337  // breakpoint. Note, unlike the step in range plan, we don't mark ourselves
338  // complete if we hit an unexplained breakpoint/crash.
339
340  Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
341  StopInfoSP stop_info_sp = GetPrivateStopInfo();
342  bool return_value;
343
344  if (stop_info_sp) {
345    StopReason reason = stop_info_sp->GetStopReason();
346
347    if (reason == eStopReasonTrace) {
348      return_value = true;
349    } else if (reason == eStopReasonBreakpoint) {
350      return_value = NextRangeBreakpointExplainsStop(stop_info_sp);
351    } else {
352      if (log)
353        log->PutCString("ThreadPlanStepInRange got asked if it explains the "
354                        "stop for some reason other than step.");
355      return_value = false;
356    }
357  } else
358    return_value = true;
359
360  return return_value;
361}
362
363bool ThreadPlanStepOverRange::DoWillResume(lldb::StateType resume_state,
364                                           bool current_plan) {
365  if (resume_state != eStateSuspended && m_first_resume) {
366    m_first_resume = false;
367    if (resume_state == eStateStepping && current_plan) {
368      // See if we are about to step over an inlined call in the middle of the
369      // inlined stack, if so figure out its extents and reset our range to
370      // step over that.
371      bool in_inlined_stack = m_thread.DecrementCurrentInlinedDepth();
372      if (in_inlined_stack) {
373        Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
374        LLDB_LOGF(log,
375                  "ThreadPlanStepInRange::DoWillResume: adjusting range to "
376                  "the frame at inlined depth %d.",
377                  m_thread.GetCurrentInlinedDepth());
378        StackFrameSP stack_sp = m_thread.GetStackFrameAtIndex(0);
379        if (stack_sp) {
380          Block *frame_block = stack_sp->GetFrameBlock();
381          lldb::addr_t curr_pc = m_thread.GetRegisterContext()->GetPC();
382          AddressRange my_range;
383          if (frame_block->GetRangeContainingLoadAddress(
384                  curr_pc, m_thread.GetProcess()->GetTarget(), my_range)) {
385            m_address_ranges.clear();
386            m_address_ranges.push_back(my_range);
387            if (log) {
388              StreamString s;
389              const InlineFunctionInfo *inline_info =
390                  frame_block->GetInlinedFunctionInfo();
391              const char *name;
392              if (inline_info)
393                name =
394                    inline_info
395                        ->GetName(frame_block->CalculateSymbolContextFunction()
396                                      ->GetLanguage())
397                        .AsCString();
398              else
399                name = "<unknown-notinlined>";
400
401              s.Printf(
402                  "Stepping over inlined function \"%s\" in inlined stack: ",
403                  name);
404              DumpRanges(&s);
405              log->PutString(s.GetString());
406            }
407          }
408        }
409      }
410    }
411  }
412
413  return true;
414}
415