1 //===-- ThreadPlanStepOverRange.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/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 
23 using namespace lldb_private;
24 using namespace lldb;
25 
26 uint32_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 
ThreadPlanStepOverRange(Thread & thread,const AddressRange & range,const SymbolContext & addr_context,lldb::RunMode stop_others,LazyBool step_out_avoids_code_without_debug_info)31 ThreadPlanStepOverRange::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 
43 ThreadPlanStepOverRange::~ThreadPlanStepOverRange() = default;
44 
GetDescription(Stream * s,lldb::DescriptionLevel level)45 void 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 
SetupAvoidNoDebug(LazyBool step_out_avoids_code_without_debug_info)77 void 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 = GetThread().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 
IsEquivalentContext(const SymbolContext & context)101 bool 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 
ShouldStop(Event * event_ptr)126 bool ThreadPlanStepOverRange::ShouldStop(Event *event_ptr) {
127   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
128   Thread &thread = GetThread();
129 
130   if (log) {
131     StreamString s;
132     DumpAddress(s.AsRawOstream(), thread.GetRegisterContext()->GetPC(),
133                 GetTarget().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 = 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 = 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         // If we have the  next-branch-breakpoint in the range, we can just
175         // rely on that breakpoint to trigger once we return to the range.
176         if (m_next_branch_bp_sp)
177           return false;
178         new_plan_sp = thread.QueueThreadPlanForStepOutNoShouldStop(
179             false, nullptr, true, stop_others, eVoteNo, eVoteNoOpinion, 0,
180             m_status, true);
181         break;
182       } else {
183         new_plan_sp = thread.QueueThreadPlanForStepThrough(
184             m_stack_id, false, stop_others, m_status);
185         // If we found a way through, then we should stop recursing.
186         if (new_plan_sp)
187           break;
188       }
189     }
190   } else {
191     // If we're still in the range, keep going.
192     if (InRange()) {
193       SetNextBranchBreakpoint();
194       return false;
195     }
196 
197     if (!InSymbol()) {
198       // This one is a little tricky.  Sometimes we may be in a stub or
199       // something similar, in which case we need to get out of there.  But if
200       // we are in a stub then it's likely going to be hard to get out from
201       // here.  It is probably easiest to step into the stub, and then it will
202       // be straight-forward to step out.
203       new_plan_sp = thread.QueueThreadPlanForStepThrough(m_stack_id, false,
204                                                          stop_others, m_status);
205     } else {
206       // The current clang (at least through 424) doesn't always get the
207       // address range for the DW_TAG_inlined_subroutines right, so that when
208       // you leave the inlined range the line table says you are still in the
209       // source file of the inlining function.  This is bad, because now you
210       // are missing the stack frame for the function containing the inlining,
211       // and if you sensibly do "finish" to get out of this function you will
212       // instead exit the containing function. To work around this, we check
213       // whether we are still in the source file we started in, and if not
214       // assume it is an error, and push a plan to get us out of this line and
215       // back to the containing file.
216 
217       if (m_addr_context.line_entry.IsValid()) {
218         SymbolContext sc;
219         StackFrameSP frame_sp = thread.GetStackFrameAtIndex(0);
220         sc = frame_sp->GetSymbolContext(eSymbolContextEverything);
221         if (sc.line_entry.IsValid()) {
222           if (sc.line_entry.original_file !=
223                   m_addr_context.line_entry.original_file &&
224               sc.comp_unit == m_addr_context.comp_unit &&
225               sc.function == m_addr_context.function) {
226             // Okay, find the next occurrence of this file in the line table:
227             LineTable *line_table = m_addr_context.comp_unit->GetLineTable();
228             if (line_table) {
229               Address cur_address = frame_sp->GetFrameCodeAddress();
230               uint32_t entry_idx;
231               LineEntry line_entry;
232               if (line_table->FindLineEntryByAddress(cur_address, line_entry,
233                                                      &entry_idx)) {
234                 LineEntry next_line_entry;
235                 bool step_past_remaining_inline = false;
236                 if (entry_idx > 0) {
237                   // We require the previous line entry and the current line
238                   // entry come from the same file. The other requirement is
239                   // that the previous line table entry be part of an inlined
240                   // block, we don't want to step past cases where people have
241                   // inlined some code fragment by using #include <source-
242                   // fragment.c> directly.
243                   LineEntry prev_line_entry;
244                   if (line_table->GetLineEntryAtIndex(entry_idx - 1,
245                                                       prev_line_entry) &&
246                       prev_line_entry.original_file ==
247                           line_entry.original_file) {
248                     SymbolContext prev_sc;
249                     Address prev_address =
250                         prev_line_entry.range.GetBaseAddress();
251                     prev_address.CalculateSymbolContext(&prev_sc);
252                     if (prev_sc.block) {
253                       Block *inlined_block =
254                           prev_sc.block->GetContainingInlinedBlock();
255                       if (inlined_block) {
256                         AddressRange inline_range;
257                         inlined_block->GetRangeContainingAddress(prev_address,
258                                                                  inline_range);
259                         if (!inline_range.ContainsFileAddress(cur_address)) {
260 
261                           step_past_remaining_inline = true;
262                         }
263                       }
264                     }
265                   }
266                 }
267 
268                 if (step_past_remaining_inline) {
269                   uint32_t look_ahead_step = 1;
270                   while (line_table->GetLineEntryAtIndex(
271                       entry_idx + look_ahead_step, next_line_entry)) {
272                     // Make sure we haven't wandered out of the function we
273                     // started from...
274                     Address next_line_address =
275                         next_line_entry.range.GetBaseAddress();
276                     Function *next_line_function =
277                         next_line_address.CalculateSymbolContextFunction();
278                     if (next_line_function != m_addr_context.function)
279                       break;
280 
281                     if (next_line_entry.original_file ==
282                         m_addr_context.line_entry.original_file) {
283                       const bool abort_other_plans = false;
284                       const RunMode stop_other_threads = RunMode::eAllThreads;
285                       lldb::addr_t cur_pc = thread.GetStackFrameAtIndex(0)
286                                                 ->GetRegisterContext()
287                                                 ->GetPC();
288                       AddressRange step_range(
289                           cur_pc,
290                           next_line_address.GetLoadAddress(&GetTarget()) -
291                               cur_pc);
292 
293                       new_plan_sp = thread.QueueThreadPlanForStepOverRange(
294                           abort_other_plans, step_range, sc, stop_other_threads,
295                           m_status);
296                       break;
297                     }
298                     look_ahead_step++;
299                   }
300                 }
301               }
302             }
303           }
304         }
305       }
306     }
307   }
308 
309   // If we get to this point, we're not going to use a previously set "next
310   // branch" breakpoint, so delete it:
311   ClearNextBranchBreakpoint();
312 
313   // If we haven't figured out something to do yet, then ask the ShouldStopHere
314   // callback:
315   if (!new_plan_sp) {
316     new_plan_sp = CheckShouldStopHereAndQueueStepOut(frame_order, m_status);
317   }
318 
319   if (!new_plan_sp)
320     m_no_more_plans = true;
321   else {
322     // Any new plan will be an implementation plan, so mark it private:
323     new_plan_sp->SetPrivate(true);
324     m_no_more_plans = false;
325   }
326 
327   if (!new_plan_sp) {
328     // For efficiencies sake, we know we're done here so we don't have to do
329     // this calculation again in MischiefManaged.
330     SetPlanComplete(m_status.Success());
331     return true;
332   } else
333     return false;
334 }
335 
DoPlanExplainsStop(Event * event_ptr)336 bool ThreadPlanStepOverRange::DoPlanExplainsStop(Event *event_ptr) {
337   // For crashes, breakpoint hits, signals, etc, let the base plan (or some
338   // plan above us) handle the stop.  That way the user can see the stop, step
339   // around, and then when they are done, continue and have their step
340   // complete.  The exception is if we've hit our "run to next branch"
341   // breakpoint. Note, unlike the step in range plan, we don't mark ourselves
342   // complete if we hit an unexplained breakpoint/crash.
343 
344   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
345   StopInfoSP stop_info_sp = GetPrivateStopInfo();
346   bool return_value;
347 
348   if (stop_info_sp) {
349     StopReason reason = stop_info_sp->GetStopReason();
350 
351     if (reason == eStopReasonTrace) {
352       return_value = true;
353     } else if (reason == eStopReasonBreakpoint) {
354       return_value = NextRangeBreakpointExplainsStop(stop_info_sp);
355     } else {
356       if (log)
357         log->PutCString("ThreadPlanStepInRange got asked if it explains the "
358                         "stop for some reason other than step.");
359       return_value = false;
360     }
361   } else
362     return_value = true;
363 
364   return return_value;
365 }
366 
DoWillResume(lldb::StateType resume_state,bool current_plan)367 bool ThreadPlanStepOverRange::DoWillResume(lldb::StateType resume_state,
368                                            bool current_plan) {
369   if (resume_state != eStateSuspended && m_first_resume) {
370     m_first_resume = false;
371     if (resume_state == eStateStepping && current_plan) {
372       Thread &thread = GetThread();
373       // See if we are about to step over an inlined call in the middle of the
374       // inlined stack, if so figure out its extents and reset our range to
375       // step over that.
376       bool in_inlined_stack = thread.DecrementCurrentInlinedDepth();
377       if (in_inlined_stack) {
378         Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
379         LLDB_LOGF(log,
380                   "ThreadPlanStepInRange::DoWillResume: adjusting range to "
381                   "the frame at inlined depth %d.",
382                   thread.GetCurrentInlinedDepth());
383         StackFrameSP stack_sp = thread.GetStackFrameAtIndex(0);
384         if (stack_sp) {
385           Block *frame_block = stack_sp->GetFrameBlock();
386           lldb::addr_t curr_pc = thread.GetRegisterContext()->GetPC();
387           AddressRange my_range;
388           if (frame_block->GetRangeContainingLoadAddress(
389                   curr_pc, m_process.GetTarget(), my_range)) {
390             m_address_ranges.clear();
391             m_address_ranges.push_back(my_range);
392             if (log) {
393               StreamString s;
394               const InlineFunctionInfo *inline_info =
395                   frame_block->GetInlinedFunctionInfo();
396               const char *name;
397               if (inline_info)
398                 name = inline_info->GetName().AsCString();
399               else
400                 name = "<unknown-notinlined>";
401 
402               s.Printf(
403                   "Stepping over inlined function \"%s\" in inlined stack: ",
404                   name);
405               DumpRanges(&s);
406               log->PutString(s.GetString());
407             }
408           }
409         }
410       }
411     }
412   }
413 
414   return true;
415 }
416