lldb/source/Target/ThreadPlanStepInRange.cpp

   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
  26 using namespace lldb;
  27 using namespace lldb_private;
  28
  29 uint32_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
  35 ThreadPlanStepInRange::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
  51 ThreadPlanStepInRange::~ThreadPlanStepInRange() = default;
  52
  53 void 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
  91 void 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
 128 bool 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
 294 void 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
 301 void ThreadPlanStepInRange::SetDefaultFlagValue(uint32_t new_value) {
 302   // TODO: Should we test this for sanity?
 303   ThreadPlanStepInRange::s_default_flag_values = new_value;
 304 }
 305
 306 bool 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
 358 bool 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
 415 bool 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
 460 bool 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
 485 bool ThreadPlanStepInRange::IsVirtualStep() { return m_virtual_step; }