text: //===-- Thread.cpp --------------------------------------------------------===//
  //
  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  // See https://llvm.org/LICENSE.txt for license information.
  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  //
  //===----------------------------------------------------------------------===//
  
  #include "lldb/Target/Thread.h"
  #include "lldb/Breakpoint/BreakpointLocation.h"
  #include "lldb/Core/Debugger.h"
  #include "lldb/Core/FormatEntity.h"
  #include "lldb/Core/Module.h"
  #include "lldb/Core/StructuredDataImpl.h"
  #include "lldb/Core/ValueObject.h"
  #include "lldb/Host/Host.h"
  #include "lldb/Interpreter/OptionValueFileSpecList.h"
  #include "lldb/Interpreter/OptionValueProperties.h"
  #include "lldb/Interpreter/Property.h"
  #include "lldb/Symbol/Function.h"
  #include "lldb/Target/ABI.h"
  #include "lldb/Target/DynamicLoader.h"
  #include "lldb/Target/ExecutionContext.h"
  #include "lldb/Target/LanguageRuntime.h"
  #include "lldb/Target/Process.h"
  #include "lldb/Target/RegisterContext.h"
  #include "lldb/Target/StackFrameRecognizer.h"
  #include "lldb/Target/StopInfo.h"
  #include "lldb/Target/SystemRuntime.h"
  #include "lldb/Target/Target.h"
  #include "lldb/Target/ThreadPlan.h"
  #include "lldb/Target/ThreadPlanBase.h"
  #include "lldb/Target/ThreadPlanCallFunction.h"
  #include "lldb/Target/ThreadPlanPython.h"
  #include "lldb/Target/ThreadPlanRunToAddress.h"
  #include "lldb/Target/ThreadPlanStack.h"
  #include "lldb/Target/ThreadPlanStepInRange.h"
  #include "lldb/Target/ThreadPlanStepInstruction.h"
  #include "lldb/Target/ThreadPlanStepOut.h"
  #include "lldb/Target/ThreadPlanStepOverBreakpoint.h"
  #include "lldb/Target/ThreadPlanStepOverRange.h"
  #include "lldb/Target/ThreadPlanStepThrough.h"
  #include "lldb/Target/ThreadPlanStepUntil.h"
  #include "lldb/Target/ThreadSpec.h"
  #include "lldb/Target/UnwindLLDB.h"
  #include "lldb/Utility/Log.h"
  #include "lldb/Utility/RegularExpression.h"
  #include "lldb/Utility/State.h"
  #include "lldb/Utility/Stream.h"
  #include "lldb/Utility/StreamString.h"
  #include "lldb/lldb-enumerations.h"
  
  #include <memory>
  
  using namespace lldb;
  using namespace lldb_private;
  
  const ThreadPropertiesSP &Thread::GetGlobalProperties() {
    // NOTE: intentional leak so we don't crash if global destructor chain gets
    // called as other threads still use the result of this function
    static ThreadPropertiesSP *g_settings_sp_ptr =
        new ThreadPropertiesSP(new ThreadProperties(true));
    return *g_settings_sp_ptr;
  }
  
  #define LLDB_PROPERTIES_thread
  #include "TargetProperties.inc"
  
  enum {
  #define LLDB_PROPERTIES_thread
  #include "TargetPropertiesEnum.inc"
  };
  
  class ThreadOptionValueProperties : public OptionValueProperties {
  public:
    ThreadOptionValueProperties(ConstString name)
        : OptionValueProperties(name) {}
  
    // This constructor is used when creating ThreadOptionValueProperties when it
    // is part of a new lldb_private::Thread instance. It will copy all current
    // global property values as needed
    ThreadOptionValueProperties(ThreadProperties *global_properties)
        : OptionValueProperties(*global_properties->GetValueProperties()) {}
  
    const Property *GetPropertyAtIndex(const ExecutionContext *exe_ctx,
                                       bool will_modify,
                                       uint32_t idx) const override {
      // When getting the value for a key from the thread options, we will always
      // try and grab the setting from the current thread if there is one. Else
      // we just use the one from this instance.
      if (exe_ctx) {
        Thread *thread = exe_ctx->GetThreadPtr();
        if (thread) {
          ThreadOptionValueProperties *instance_properties =
              static_cast<ThreadOptionValueProperties *>(
                  thread->GetValueProperties().get());
          if (this != instance_properties)
            return instance_properties->ProtectedGetPropertyAtIndex(idx);
        }
      }
      return ProtectedGetPropertyAtIndex(idx);
    }
  };
  
  ThreadProperties::ThreadProperties(bool is_global) : Properties() {
    if (is_global) {
      m_collection_sp =
          std::make_shared<ThreadOptionValueProperties>(ConstString("thread"));
      m_collection_sp->Initialize(g_thread_properties);
    } else
      m_collection_sp = std::make_shared<ThreadOptionValueProperties>(
          Thread::GetGlobalProperties().get());
  }
  
  ThreadProperties::~ThreadProperties() = default;
  
  const RegularExpression *ThreadProperties::GetSymbolsToAvoidRegexp() {
    const uint32_t idx = ePropertyStepAvoidRegex;
    return m_collection_sp->GetPropertyAtIndexAsOptionValueRegex(nullptr, idx);
  }
  
  FileSpecList ThreadProperties::GetLibrariesToAvoid() const {
    const uint32_t idx = ePropertyStepAvoidLibraries;
    const OptionValueFileSpecList *option_value =
        m_collection_sp->GetPropertyAtIndexAsOptionValueFileSpecList(nullptr,
                                                                     false, idx);
    assert(option_value);
    return option_value->GetCurrentValue();
  }
  
  bool ThreadProperties::GetTraceEnabledState() const {
    const uint32_t idx = ePropertyEnableThreadTrace;
    return m_collection_sp->GetPropertyAtIndexAsBoolean(
        nullptr, idx, g_thread_properties[idx].default_uint_value != 0);
  }
  
  bool ThreadProperties::GetStepInAvoidsNoDebug() const {
    const uint32_t idx = ePropertyStepInAvoidsNoDebug;
    return m_collection_sp->GetPropertyAtIndexAsBoolean(
        nullptr, idx, g_thread_properties[idx].default_uint_value != 0);
  }
  
  bool ThreadProperties::GetStepOutAvoidsNoDebug() const {
    const uint32_t idx = ePropertyStepOutAvoidsNoDebug;
    return m_collection_sp->GetPropertyAtIndexAsBoolean(
        nullptr, idx, g_thread_properties[idx].default_uint_value != 0);
  }
  
  uint64_t ThreadProperties::GetMaxBacktraceDepth() const {
    const uint32_t idx = ePropertyMaxBacktraceDepth;
    return m_collection_sp->GetPropertyAtIndexAsUInt64(
        nullptr, idx, g_thread_properties[idx].default_uint_value != 0);
  }
  
  // Thread Event Data
  
  ConstString Thread::ThreadEventData::GetFlavorString() {
    static ConstString g_flavor("Thread::ThreadEventData");
    return g_flavor;
  }
  
  Thread::ThreadEventData::ThreadEventData(const lldb::ThreadSP thread_sp)
      : m_thread_sp(thread_sp), m_stack_id() {}
  
  Thread::ThreadEventData::ThreadEventData(const lldb::ThreadSP thread_sp,
                                           const StackID &stack_id)
      : m_thread_sp(thread_sp), m_stack_id(stack_id) {}
  
  Thread::ThreadEventData::ThreadEventData() : m_thread_sp(), m_stack_id() {}
  
  Thread::ThreadEventData::~ThreadEventData() = default;
  
  void Thread::ThreadEventData::Dump(Stream *s) const {}
  
  const Thread::ThreadEventData *
  Thread::ThreadEventData::GetEventDataFromEvent(const Event *event_ptr) {
    if (event_ptr) {
      const EventData *event_data = event_ptr->GetData();
      if (event_data &&
          event_data->GetFlavor() == ThreadEventData::GetFlavorString())
        return static_cast<const ThreadEventData *>(event_ptr->GetData());
    }
    return nullptr;
  }
  
  ThreadSP Thread::ThreadEventData::GetThreadFromEvent(const Event *event_ptr) {
    ThreadSP thread_sp;
    const ThreadEventData *event_data = GetEventDataFromEvent(event_ptr);
    if (event_data)
      thread_sp = event_data->GetThread();
    return thread_sp;
  }
  
  StackID Thread::ThreadEventData::GetStackIDFromEvent(const Event *event_ptr) {
    StackID stack_id;
    const ThreadEventData *event_data = GetEventDataFromEvent(event_ptr);
    if (event_data)
      stack_id = event_data->GetStackID();
    return stack_id;
  }
  
  StackFrameSP
  Thread::ThreadEventData::GetStackFrameFromEvent(const Event *event_ptr) {
    const ThreadEventData *event_data = GetEventDataFromEvent(event_ptr);
    StackFrameSP frame_sp;
    if (event_data) {
      ThreadSP thread_sp = event_data->GetThread();
      if (thread_sp) {
        frame_sp = thread_sp->GetStackFrameList()->GetFrameWithStackID(
            event_data->GetStackID());
      }
    }
    return frame_sp;
  }
  
  // Thread class
  
  ConstString &Thread::GetStaticBroadcasterClass() {
    static ConstString class_name("lldb.thread");
    return class_name;
  }
  
  Thread::Thread(Process &process, lldb::tid_t tid, bool use_invalid_index_id)
      : ThreadProperties(false), UserID(tid),
        Broadcaster(process.GetTarget().GetDebugger().GetBroadcasterManager(),
                    Thread::GetStaticBroadcasterClass().AsCString()),
        m_process_wp(process.shared_from_this()), m_stop_info_sp(),
        m_stop_info_stop_id(0), m_stop_info_override_stop_id(0),
        m_index_id(use_invalid_index_id ? LLDB_INVALID_INDEX32
                                        : process.GetNextThreadIndexID(tid)),
        m_reg_context_sp(), m_state(eStateUnloaded), m_state_mutex(),
        m_frame_mutex(), m_curr_frames_sp(), m_prev_frames_sp(),
        m_resume_signal(LLDB_INVALID_SIGNAL_NUMBER),
        m_resume_state(eStateRunning), m_temporary_resume_state(eStateRunning),
        m_unwinder_up(), m_destroy_called(false),
        m_override_should_notify(eLazyBoolCalculate),
        m_extended_info_fetched(false), m_extended_info() {
    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_OBJECT));
    LLDB_LOGF(log, "%p Thread::Thread(tid = 0x%4.4" PRIx64 ")",
              static_cast<void *>(this), GetID());
  
    CheckInWithManager();
  }
  
  Thread::~Thread() {
    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_OBJECT));
    LLDB_LOGF(log, "%p Thread::~Thread(tid = 0x%4.4" PRIx64 ")",
              static_cast<void *>(this), GetID());
    /// If you hit this assert, it means your derived class forgot to call
    /// DoDestroy in its destructor.
    assert(m_destroy_called);
  }
  
  void Thread::DestroyThread() {
    m_destroy_called = true;
    m_stop_info_sp.reset();
    m_reg_context_sp.reset();
    m_unwinder_up.reset();
    std::lock_guard<std::recursive_mutex> guard(m_frame_mutex);
    m_curr_frames_sp.reset();
    m_prev_frames_sp.reset();
  }
  
  void Thread::BroadcastSelectedFrameChange(StackID &new_frame_id) {
    if (EventTypeHasListeners(eBroadcastBitSelectedFrameChanged))
      BroadcastEvent(eBroadcastBitSelectedFrameChanged,
                     new ThreadEventData(this->shared_from_this(), new_frame_id));
  }
  
  lldb::StackFrameSP Thread::GetSelectedFrame() {
    StackFrameListSP stack_frame_list_sp(GetStackFrameList());
    StackFrameSP frame_sp = stack_frame_list_sp->GetFrameAtIndex(
        stack_frame_list_sp->GetSelectedFrameIndex());
    FrameSelectedCallback(frame_sp.get());
    return frame_sp;
  }
  
  uint32_t Thread::SetSelectedFrame(lldb_private::StackFrame *frame,
                                    bool broadcast) {
    uint32_t ret_value = GetStackFrameList()->SetSelectedFrame(frame);
    if (broadcast)
      BroadcastSelectedFrameChange(frame->GetStackID());
    FrameSelectedCallback(frame);
    return ret_value;
  }
  
  bool Thread::SetSelectedFrameByIndex(uint32_t frame_idx, bool broadcast) {
    StackFrameSP frame_sp(GetStackFrameList()->GetFrameAtIndex(frame_idx));
    if (frame_sp) {
      GetStackFrameList()->SetSelectedFrame(frame_sp.get());
      if (broadcast)
        BroadcastSelectedFrameChange(frame_sp->GetStackID());
      FrameSelectedCallback(frame_sp.get());
      return true;
    } else
      return false;
  }
  
  bool Thread::SetSelectedFrameByIndexNoisily(uint32_t frame_idx,
                                              Stream &output_stream) {
    const bool broadcast = true;
    bool success = SetSelectedFrameByIndex(frame_idx, broadcast);
    if (success) {
      StackFrameSP frame_sp = GetSelectedFrame();
      if (frame_sp) {
        bool already_shown = false;
        SymbolContext frame_sc(
            frame_sp->GetSymbolContext(eSymbolContextLineEntry));
        if (GetProcess()->GetTarget().GetDebugger().GetUseExternalEditor() &&
            frame_sc.line_entry.file && frame_sc.line_entry.line != 0) {
          already_shown = Host::OpenFileInExternalEditor(
              frame_sc.line_entry.file, frame_sc.line_entry.line);
        }
  
        bool show_frame_info = true;
        bool show_source = !already_shown;
        FrameSelectedCallback(frame_sp.get());
        return frame_sp->GetStatus(output_stream, show_frame_info, show_source);
      }
      return false;
    } else
      return false;
  }
  
  void Thread::FrameSelectedCallback(StackFrame *frame) {
    if (!frame)
      return;
  
    if (frame->HasDebugInformation() && GetProcess()->GetWarningsOptimization()) {
      SymbolContext sc =
          frame->GetSymbolContext(eSymbolContextFunction | eSymbolContextModule);
      GetProcess()->PrintWarningOptimization(sc);
    }
    SymbolContext msc = frame->GetSymbolContext(eSymbolContextModule);
    if (msc.module_sp)
      msc.module_sp->ForEachTypeSystem([&](TypeSystem *ts) {
        if (ts)
          ts->DiagnoseWarnings(*GetProcess(), *msc.module_sp);
        return true;
      });
  }
  
  lldb::StopInfoSP Thread::GetStopInfo() {
    if (m_destroy_called)
      return m_stop_info_sp;
  
    ThreadPlanSP completed_plan_sp(GetCompletedPlan());
    ProcessSP process_sp(GetProcess());
    const uint32_t stop_id = process_sp ? process_sp->GetStopID() : UINT32_MAX;
  
    // Here we select the stop info according to priorirty: - m_stop_info_sp (if
    // not trace) - preset value - completed plan stop info - new value with plan
    // from completed plan stack - m_stop_info_sp (trace stop reason is OK now) -
    // ask GetPrivateStopInfo to set stop info
  
    bool have_valid_stop_info = m_stop_info_sp &&
        m_stop_info_sp ->IsValid() &&
        m_stop_info_stop_id == stop_id;
    bool have_valid_completed_plan = completed_plan_sp && completed_plan_sp->PlanSucceeded();
    bool plan_failed = completed_plan_sp && !completed_plan_sp->PlanSucceeded();
    bool plan_overrides_trace =
      have_valid_stop_info && have_valid_completed_plan
      && (m_stop_info_sp->GetStopReason() == eStopReasonTrace);
  
    if (have_valid_stop_info && !plan_overrides_trace && !plan_failed) {
      return m_stop_info_sp;
    } else if (completed_plan_sp) {
      bool is_swift_error_value;
      lldb::ValueObjectSP return_value_sp =
          GetReturnValueObject(&is_swift_error_value);
      return StopInfo::CreateStopReasonWithPlan(
          completed_plan_sp, return_value_sp, GetExpressionVariable(),
          is_swift_error_value);
    } else {
      GetPrivateStopInfo();
      return m_stop_info_sp;
    }
  }
  
  void Thread::CalculatePublicStopInfo() {
    ResetStopInfo();
    SetStopInfo(GetStopInfo());
  }
  
  lldb::StopInfoSP Thread::GetPrivateStopInfo() {
    if (m_destroy_called)
      return m_stop_info_sp;
  
    ProcessSP process_sp(GetProcess());
    if (process_sp) {
      const uint32_t process_stop_id = process_sp->GetStopID();
      if (m_stop_info_stop_id != process_stop_id) {
        if (m_stop_info_sp) {
          if (m_stop_info_sp->IsValid() || IsStillAtLastBreakpointHit() ||
              GetCurrentPlan()->IsVirtualStep())
            SetStopInfo(m_stop_info_sp);
          else
            m_stop_info_sp.reset();
        }
  
        if (!m_stop_info_sp) {
          if (!CalculateStopInfo())
            SetStopInfo(StopInfoSP());
        }
      }
  
      // The stop info can be manually set by calling Thread::SetStopInfo() prior
      // to this function ever getting called, so we can't rely on
      // "m_stop_info_stop_id != process_stop_id" as the condition for the if
      // statement below, we must also check the stop info to see if we need to
      // override it. See the header documentation in
      // Architecture::OverrideStopInfo() for more information on the stop
      // info override callback.
      if (m_stop_info_override_stop_id != process_stop_id) {
        m_stop_info_override_stop_id = process_stop_id;
        if (m_stop_info_sp) {
          if (const Architecture *arch =
                  process_sp->GetTarget().GetArchitecturePlugin())
            arch->OverrideStopInfo(*this);
        }
      }
    }
    return m_stop_info_sp;
  }
  
  lldb::StopReason Thread::GetStopReason() {
    lldb::StopInfoSP stop_info_sp(GetStopInfo());
    if (stop_info_sp)
      return stop_info_sp->GetStopReason();
    return eStopReasonNone;
  }
  
  bool Thread::StopInfoIsUpToDate() const {
    ProcessSP process_sp(GetProcess());
    if (process_sp)
      return m_stop_info_stop_id == process_sp->GetStopID();
    else
      return true; // Process is no longer around so stop info is always up to
                   // date...
  }
  
  void Thread::ResetStopInfo() {
    if (m_stop_info_sp) {
      m_stop_info_sp.reset();
    }
  }
  
  void Thread::SetStopInfo(const lldb::StopInfoSP &stop_info_sp) {
    m_stop_info_sp = stop_info_sp;
    if (m_stop_info_sp) {
      m_stop_info_sp->MakeStopInfoValid();
      // If we are overriding the ShouldReportStop, do that here:
      if (m_override_should_notify != eLazyBoolCalculate)
        m_stop_info_sp->OverrideShouldNotify(m_override_should_notify ==
                                             eLazyBoolYes);
    }
  
    ProcessSP process_sp(GetProcess());
    if (process_sp)
      m_stop_info_stop_id = process_sp->GetStopID();
    else
      m_stop_info_stop_id = UINT32_MAX;
    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
    LLDB_LOGF(log, "%p: tid = 0x%" PRIx64 ": stop info = %s (stop_id = %u)",
              static_cast<void *>(this), GetID(),
              stop_info_sp ? stop_info_sp->GetDescription() : "<NULL>",
              m_stop_info_stop_id);
  }
  
  void Thread::SetShouldReportStop(Vote vote) {
    if (vote == eVoteNoOpinion)
      return;
    else {
      m_override_should_notify = (vote == eVoteYes ? eLazyBoolYes : eLazyBoolNo);
      if (m_stop_info_sp)
        m_stop_info_sp->OverrideShouldNotify(m_override_should_notify ==
                                             eLazyBoolYes);
    }
  }
  
  void Thread::SetStopInfoToNothing() {
    // Note, we can't just NULL out the private reason, or the native thread
    // implementation will try to go calculate it again.  For now, just set it to
    // a Unix Signal with an invalid signal number.
    SetStopInfo(
        StopInfo::CreateStopReasonWithSignal(*this, LLDB_INVALID_SIGNAL_NUMBER));
  }
  
  bool Thread::ThreadStoppedForAReason(void) {
    return (bool)GetPrivateStopInfo();
  }
  
  bool Thread::CheckpointThreadState(ThreadStateCheckpoint &saved_state) {
    saved_state.register_backup_sp.reset();
    lldb::StackFrameSP frame_sp(GetStackFrameAtIndex(0));
    if (frame_sp) {
      lldb::RegisterCheckpointSP reg_checkpoint_sp(
          new RegisterCheckpoint(RegisterCheckpoint::Reason::eExpression));
      if (reg_checkpoint_sp) {
        lldb::RegisterContextSP reg_ctx_sp(frame_sp->GetRegisterContext());
        if (reg_ctx_sp && reg_ctx_sp->ReadAllRegisterValues(*reg_checkpoint_sp))
          saved_state.register_backup_sp = reg_checkpoint_sp;
      }
    }
    if (!saved_state.register_backup_sp)
      return false;
  
    saved_state.stop_info_sp = GetStopInfo();
    ProcessSP process_sp(GetProcess());
    if (process_sp)
      saved_state.orig_stop_id = process_sp->GetStopID();
    saved_state.current_inlined_depth = GetCurrentInlinedDepth();
    saved_state.m_completed_plan_checkpoint =
        GetPlans().CheckpointCompletedPlans();
  
    return true;
  }
  
  bool Thread::RestoreRegisterStateFromCheckpoint(
      ThreadStateCheckpoint &saved_state) {
    if (saved_state.register_backup_sp) {
      lldb::StackFrameSP frame_sp(GetStackFrameAtIndex(0));
      if (frame_sp) {
        lldb::RegisterContextSP reg_ctx_sp(frame_sp->GetRegisterContext());
        if (reg_ctx_sp) {
          bool ret =
              reg_ctx_sp->WriteAllRegisterValues(*saved_state.register_backup_sp);
  
          // Clear out all stack frames as our world just changed.
          ClearStackFrames();
          reg_ctx_sp->InvalidateIfNeeded(true);
          if (m_unwinder_up)
            m_unwinder_up->Clear();
          return ret;
        }
      }
    }
    return false;
  }
  
  bool Thread::RestoreThreadStateFromCheckpoint(
      ThreadStateCheckpoint &saved_state) {
    if (saved_state.stop_info_sp)
      saved_state.stop_info_sp->MakeStopInfoValid();
    SetStopInfo(saved_state.stop_info_sp);
    GetStackFrameList()->SetCurrentInlinedDepth(
        saved_state.current_inlined_depth);
    GetPlans().RestoreCompletedPlanCheckpoint(
        saved_state.m_completed_plan_checkpoint);
    return true;
  }
  
  StateType Thread::GetState() const {
    // If any other threads access this we will need a mutex for it
    std::lock_guard<std::recursive_mutex> guard(m_state_mutex);
    return m_state;
  }
  
  void Thread::SetState(StateType state) {
    std::lock_guard<std::recursive_mutex> guard(m_state_mutex);
    m_state = state;
  }
  
  std::string Thread::GetStopDescription() {
    StackFrameSP frame_sp = GetStackFrameAtIndex(0);
  
    if (!frame_sp)
      return GetStopDescriptionRaw();
  
    auto recognized_frame_sp = frame_sp->GetRecognizedFrame();
  
    if (!recognized_frame_sp)
      return GetStopDescriptionRaw();
  
    std::string recognized_stop_description =
        recognized_frame_sp->GetStopDescription();
  
    if (!recognized_stop_description.empty())
      return recognized_stop_description;
  
    return GetStopDescriptionRaw();
  }
  
  std::string Thread::GetStopDescriptionRaw() {
    StopInfoSP stop_info_sp = GetStopInfo();
    std::string raw_stop_description;
    if (stop_info_sp && stop_info_sp->IsValid()) {
      raw_stop_description = stop_info_sp->GetDescription();
      assert((!raw_stop_description.empty() ||
              stop_info_sp->GetStopReason() == eStopReasonNone) &&
             "StopInfo returned an empty description.");
    }
    return raw_stop_description;
  }
  
  void Thread::SelectMostRelevantFrame() {
    Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD);
  
    auto frames_list_sp = GetStackFrameList();
  
    // Only the top frame should be recognized.
    auto frame_sp = frames_list_sp->GetFrameAtIndex(0);
  
    auto recognized_frame_sp = frame_sp->GetRecognizedFrame();
  
    if (!recognized_frame_sp) {
      LLDB_LOG(log, "Frame #0 not recognized");
      return;
    }
  
    if (StackFrameSP most_relevant_frame_sp =
            recognized_frame_sp->GetMostRelevantFrame()) {
      LLDB_LOG(log, "Found most relevant frame at index {0}",
               most_relevant_frame_sp->GetFrameIndex());
      SetSelectedFrame(most_relevant_frame_sp.get());
    } else {
      LLDB_LOG(log, "No relevant frame!");
    }
  }
  
  void Thread::WillStop() {
    ThreadPlan *current_plan = GetCurrentPlan();
  
    SelectMostRelevantFrame();
  
    // FIXME: I may decide to disallow threads with no plans.  In which
    // case this should go to an assert.
  
    if (!current_plan)
      return;
  
    current_plan->WillStop();
  }
  
  void Thread::SetupForResume() {
    if (GetResumeState() != eStateSuspended) {
      // If we're at a breakpoint push the step-over breakpoint plan.  Do this
      // before telling the current plan it will resume, since we might change
      // what the current plan is.
  
      lldb::RegisterContextSP reg_ctx_sp(GetRegisterContext());
      if (reg_ctx_sp) {
        const addr_t thread_pc = reg_ctx_sp->GetPC();
        BreakpointSiteSP bp_site_sp =
            GetProcess()->GetBreakpointSiteList().FindByAddress(thread_pc);
        if (bp_site_sp) {
          // Note, don't assume there's a ThreadPlanStepOverBreakpoint, the
          // target may not require anything special to step over a breakpoint.
  
          ThreadPlan *cur_plan = GetCurrentPlan();
  
          bool push_step_over_bp_plan = false;
          if (cur_plan->GetKind() == ThreadPlan::eKindStepOverBreakpoint) {
            ThreadPlanStepOverBreakpoint *bp_plan =
                (ThreadPlanStepOverBreakpoint *)cur_plan;
            if (bp_plan->GetBreakpointLoadAddress() != thread_pc)
              push_step_over_bp_plan = true;
          } else
            push_step_over_bp_plan = true;
  
          if (push_step_over_bp_plan) {
            ThreadPlanSP step_bp_plan_sp(new ThreadPlanStepOverBreakpoint(*this));
            if (step_bp_plan_sp) {
              step_bp_plan_sp->SetPrivate(true);
  
              if (GetCurrentPlan()->RunState() != eStateStepping) {
                ThreadPlanStepOverBreakpoint *step_bp_plan =
                    static_cast<ThreadPlanStepOverBreakpoint *>(
                        step_bp_plan_sp.get());
                step_bp_plan->SetAutoContinue(true);
              }
              QueueThreadPlan(step_bp_plan_sp, false);
            }
          }
        }
      }
    }
  }
  
  bool Thread::ShouldResume(StateType resume_state) {
    // At this point clear the completed plan stack.
    GetPlans().WillResume();
    m_override_should_notify = eLazyBoolCalculate;
  
    StateType prev_resume_state = GetTemporaryResumeState();
  
    SetTemporaryResumeState(resume_state);
  
    lldb::ThreadSP backing_thread_sp(GetBackingThread());
    if (backing_thread_sp)
      backing_thread_sp->SetTemporaryResumeState(resume_state);
  
    // Make sure m_stop_info_sp is valid.  Don't do this for threads we suspended
    // in the previous run.
    if (prev_resume_state != eStateSuspended)
      GetPrivateStopInfo();
  
    // This is a little dubious, but we are trying to limit how often we actually
    // fetch stop info from the target, 'cause that slows down single stepping.
    // So assume that if we got to the point where we're about to resume, and we
    // haven't yet had to fetch the stop reason, then it doesn't need to know
    // about the fact that we are resuming...
    const uint32_t process_stop_id = GetProcess()->GetStopID();
    if (m_stop_info_stop_id == process_stop_id &&
        (m_stop_info_sp && m_stop_info_sp->IsValid())) {
      StopInfo *stop_info = GetPrivateStopInfo().get();
      if (stop_info)
        stop_info->WillResume(resume_state);
    }
  
    // Tell all the plans that we are about to resume in case they need to clear
    // any state. We distinguish between the plan on the top of the stack and the
    // lower plans in case a plan needs to do any special business before it
    // runs.
  
    bool need_to_resume = false;
    ThreadPlan *plan_ptr = GetCurrentPlan();
    if (plan_ptr) {
      need_to_resume = plan_ptr->WillResume(resume_state, true);
  
      while ((plan_ptr = GetPreviousPlan(plan_ptr)) != nullptr) {
        plan_ptr->WillResume(resume_state, false);
      }
  
      // If the WillResume for the plan says we are faking a resume, then it will
      // have set an appropriate stop info. In that case, don't reset it here.
  
      if (need_to_resume && resume_state != eStateSuspended) {
        m_stop_info_sp.reset();
      }
    }
  
    if (need_to_resume) {
      ClearStackFrames();
      // Let Thread subclasses do any special work they need to prior to resuming
      WillResume(resume_state);
    }
  
    return need_to_resume;
  }
  
  void Thread::DidResume() { SetResumeSignal(LLDB_INVALID_SIGNAL_NUMBER); }
  
  void Thread::DidStop() { SetState(eStateStopped); }
  
  bool Thread::ShouldStop(Event *event_ptr) {
    ThreadPlan *current_plan = GetCurrentPlan();
  
    bool should_stop = true;
  
    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
  
    if (GetResumeState() == eStateSuspended) {
      LLDB_LOGF(log,
                "Thread::%s for tid = 0x%4.4" PRIx64 " 0x%4.4" PRIx64
                ", should_stop = 0 (ignore since thread was suspended)",
                __FUNCTION__, GetID(), GetProtocolID());
      return false;
    }
  
    if (GetTemporaryResumeState() == eStateSuspended) {
      LLDB_LOGF(log,
                "Thread::%s for tid = 0x%4.4" PRIx64 " 0x%4.4" PRIx64
                ", should_stop = 0 (ignore since thread was suspended)",
                __FUNCTION__, GetID(), GetProtocolID());
      return false;
    }
  
    // Based on the current thread plan and process stop info, check if this
    // thread caused the process to stop. NOTE: this must take place before the
    // plan is moved from the current plan stack to the completed plan stack.
    if (!ThreadStoppedForAReason()) {
      LLDB_LOGF(log,
                "Thread::%s for tid = 0x%4.4" PRIx64 " 0x%4.4" PRIx64
                ", pc = 0x%16.16" PRIx64
                ", should_stop = 0 (ignore since no stop reason)",
                __FUNCTION__, GetID(), GetProtocolID(),
                GetRegisterContext() ? GetRegisterContext()->GetPC()
                                     : LLDB_INVALID_ADDRESS);
      return false;
    }
  
    if (log) {
      LLDB_LOGF(log,
                "Thread::%s(%p) for tid = 0x%4.4" PRIx64 " 0x%4.4" PRIx64
                ", pc = 0x%16.16" PRIx64,
                __FUNCTION__, static_cast<void *>(this), GetID(), GetProtocolID(),
                GetRegisterContext() ? GetRegisterContext()->GetPC()
                                     : LLDB_INVALID_ADDRESS);
      LLDB_LOGF(log, "^^^^^^^^ Thread::ShouldStop Begin ^^^^^^^^");
      StreamString s;
      s.IndentMore();
      GetProcess()->DumpThreadPlansForTID(
          s, GetID(), eDescriptionLevelVerbose, true /* internal */,
          false /* condense_trivial */, true /* skip_unreported */);
      LLDB_LOGF(log, "Plan stack initial state:\n%s", s.GetData());
    }
  
    // The top most plan always gets to do the trace log...
    current_plan->DoTraceLog();
  
    // First query the stop info's ShouldStopSynchronous.  This handles
    // "synchronous" stop reasons, for example the breakpoint command on internal
    // breakpoints.  If a synchronous stop reason says we should not stop, then
    // we don't have to do any more work on this stop.
    StopInfoSP private_stop_info(GetPrivateStopInfo());
    if (private_stop_info &&
        !private_stop_info->ShouldStopSynchronous(event_ptr)) {
      LLDB_LOGF(log, "StopInfo::ShouldStop async callback says we should not "
                     "stop, returning ShouldStop of false.");
      return false;
    }
  
    // If we've already been restarted, don't query the plans since the state
    // they would examine is not current.
    if (Process::ProcessEventData::GetRestartedFromEvent(event_ptr))
      return false;
  
    // Before the plans see the state of the world, calculate the current inlined
    // depth.
    GetStackFrameList()->CalculateCurrentInlinedDepth();
  
    // If the base plan doesn't understand why we stopped, then we have to find a
    // plan that does. If that plan is still working, then we don't need to do
    // any more work.  If the plan that explains the stop is done, then we should
    // pop all the plans below it, and pop it, and then let the plans above it
    // decide whether they still need to do more work.
  
    bool done_processing_current_plan = false;
  
    if (!current_plan->PlanExplainsStop(event_ptr)) {
      if (current_plan->TracerExplainsStop()) {
        done_processing_current_plan = true;
        should_stop = false;
      } else {
        // If the current plan doesn't explain the stop, then find one that does
        // and let it handle the situation.
        ThreadPlan *plan_ptr = current_plan;
        while ((plan_ptr = GetPreviousPlan(plan_ptr)) != nullptr) {
          if (plan_ptr->PlanExplainsStop(event_ptr)) {
            should_stop = plan_ptr->ShouldStop(event_ptr);
  
            // plan_ptr explains the stop, next check whether plan_ptr is done,
            // if so, then we should take it and all the plans below it off the
            // stack.
  
            if (plan_ptr->MischiefManaged()) {
              // We're going to pop the plans up to and including the plan that
              // explains the stop.
              ThreadPlan *prev_plan_ptr = GetPreviousPlan(plan_ptr);
  
              do {
                if (should_stop)
                  current_plan->WillStop();
                PopPlan();
              } while ((current_plan = GetCurrentPlan()) != prev_plan_ptr);
              // Now, if the responsible plan was not "Okay to discard" then
              // we're done, otherwise we forward this to the next plan in the
              // stack below.
              done_processing_current_plan =
                  (plan_ptr->IsMasterPlan() && !plan_ptr->OkayToDiscard());
            } else
              done_processing_current_plan = true;
  
            break;
          }
        }
      }
    }
  
    if (!done_processing_current_plan) {
      bool over_ride_stop = current_plan->ShouldAutoContinue(event_ptr);
  
      LLDB_LOGF(log, "Plan %s explains stop, auto-continue %i.",
                current_plan->GetName(), over_ride_stop);
  
      // We're starting from the base plan, so just let it decide;
      if (current_plan->IsBasePlan()) {
        should_stop = current_plan->ShouldStop(event_ptr);
        LLDB_LOGF(log, "Base plan says should stop: %i.", should_stop);
      } else {
        // Otherwise, don't let the base plan override what the other plans say
        // to do, since presumably if there were other plans they would know what
        // to do...
        while (true) {
          if (current_plan->IsBasePlan())
            break;
  
          should_stop = current_plan->ShouldStop(event_ptr);
          LLDB_LOGF(log, "Plan %s should stop: %d.", current_plan->GetName(),
                    should_stop);
          if (current_plan->MischiefManaged()) {
            if (should_stop)
              current_plan->WillStop();
  
            // If a Master Plan wants to stop, and wants to stick on the stack,
            // we let it. Otherwise, see if the plan's parent wants to stop.
  
            if (should_stop && current_plan->IsMasterPlan() &&
                !current_plan->OkayToDiscard()) {
              PopPlan();
              break;
            } else {
              PopPlan();
  
              current_plan = GetCurrentPlan();
              if (current_plan == nullptr) {
                break;
              }
            }
          } else {
            break;
          }
        }
      }
  
      if (over_ride_stop)
        should_stop = false;
    }
  
    // One other potential problem is that we set up a master plan, then stop in
    // before it is complete - for instance by hitting a breakpoint during a
    // step-over - then do some step/finish/etc operations that wind up past the
    // end point condition of the initial plan.  We don't want to strand the
    // original plan on the stack, This code clears stale plans off the stack.
  
    if (should_stop) {
      ThreadPlan *plan_ptr = GetCurrentPlan();
  
      // Discard the stale plans and all plans below them in the stack, plus move
      // the completed plans to the completed plan stack
      while (!plan_ptr->IsBasePlan()) {
        bool stale = plan_ptr->IsPlanStale();
        ThreadPlan *examined_plan = plan_ptr;
        plan_ptr = GetPreviousPlan(examined_plan);
  
        if (stale) {
          LLDB_LOGF(
              log,
              "Plan %s being discarded in cleanup, it says it is already done.",
              examined_plan->GetName());
          while (GetCurrentPlan() != examined_plan) {
            DiscardPlan();
          }
          if (examined_plan->IsPlanComplete()) {
            // plan is complete but does not explain the stop (example: step to a
            // line with breakpoint), let us move the plan to
            // completed_plan_stack anyway
            PopPlan();
          } else
            DiscardPlan();
        }
      }
    }
  
    if (log) {
      StreamString s;
      s.IndentMore();
      GetProcess()->DumpThreadPlansForTID(
          s, GetID(), eDescriptionLevelVerbose, true /* internal */,
          false /* condense_trivial */, true /* skip_unreported */);
      LLDB_LOGF(log, "Plan stack final state:\n%s", s.GetData());
      LLDB_LOGF(log, "vvvvvvvv Thread::ShouldStop End (returning %i) vvvvvvvv",
                should_stop);
    }
    return should_stop;
  }
  
  Vote Thread::ShouldReportStop(Event *event_ptr) {
    StateType thread_state = GetResumeState();
    StateType temp_thread_state = GetTemporaryResumeState();
  
    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
  
    if (thread_state == eStateSuspended || thread_state == eStateInvalid) {
      LLDB_LOGF(log,
                "Thread::ShouldReportStop() tid = 0x%4.4" PRIx64
                ": returning vote %i (state was suspended or invalid)",
                GetID(), eVoteNoOpinion);
      return eVoteNoOpinion;
    }
  
    if (temp_thread_state == eStateSuspended ||
        temp_thread_state == eStateInvalid) {
      LLDB_LOGF(log,
                "Thread::ShouldReportStop() tid = 0x%4.4" PRIx64
                ": returning vote %i (temporary state was suspended or invalid)",
                GetID(), eVoteNoOpinion);
      return eVoteNoOpinion;
    }
  
    if (!ThreadStoppedForAReason()) {
      LLDB_LOGF(log,
                "Thread::ShouldReportStop() tid = 0x%4.4" PRIx64
                ": returning vote %i (thread didn't stop for a reason.)",
                GetID(), eVoteNoOpinion);
      return eVoteNoOpinion;
    }
  
    if (GetPlans().AnyCompletedPlans()) {
      // Pass skip_private = false to GetCompletedPlan, since we want to ask 
      // the last plan, regardless of whether it is private or not.
      LLDB_LOGF(log,
                "Thread::ShouldReportStop() tid = 0x%4.4" PRIx64
                ": returning vote  for complete stack's back plan",
                GetID());
      return GetPlans().GetCompletedPlan(false)->ShouldReportStop(event_ptr);
    } else {
      Vote thread_vote = eVoteNoOpinion;
      ThreadPlan *plan_ptr = GetCurrentPlan();
      while (true) {
        if (plan_ptr->PlanExplainsStop(event_ptr)) {
          thread_vote = plan_ptr->ShouldReportStop(event_ptr);
          break;
        }
        if (plan_ptr->IsBasePlan())
          break;
        else
          plan_ptr = GetPreviousPlan(plan_ptr);
      }
      LLDB_LOGF(log,
                "Thread::ShouldReportStop() tid = 0x%4.4" PRIx64
                ": returning vote %i for current plan",
                GetID(), thread_vote);
  
      return thread_vote;
    }
  }
  
  Vote Thread::ShouldReportRun(Event *event_ptr) {
    StateType thread_state = GetResumeState();
  
    if (thread_state == eStateSuspended || thread_state == eStateInvalid) {
      return eVoteNoOpinion;
    }
  
    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
    if (GetPlans().AnyCompletedPlans()) {
      // Pass skip_private = false to GetCompletedPlan, since we want to ask 
      // the last plan, regardless of whether it is private or not.
      LLDB_LOGF(log,
                "Current Plan for thread %d(%p) (0x%4.4" PRIx64
                ", %s): %s being asked whether we should report run.",
                GetIndexID(), static_cast<void *>(this), GetID(),
                StateAsCString(GetTemporaryResumeState()),
                GetCompletedPlan()->GetName());
  
      return GetPlans().GetCompletedPlan(false)->ShouldReportRun(event_ptr);
    } else {
      LLDB_LOGF(log,
                "Current Plan for thread %d(%p) (0x%4.4" PRIx64
                ", %s): %s being asked whether we should report run.",
                GetIndexID(), static_cast<void *>(this), GetID(),
                StateAsCString(GetTemporaryResumeState()),
                GetCurrentPlan()->GetName());
  
      return GetCurrentPlan()->ShouldReportRun(event_ptr);
    }
  }
  
  bool Thread::MatchesSpec(const ThreadSpec *spec) {
    return (spec == nullptr) ? true : spec->ThreadPassesBasicTests(*this);
  }
  
  ThreadPlanStack &Thread::GetPlans() const {
    ThreadPlanStack *plans = GetProcess()->FindThreadPlans(GetID());
    if (plans)
      return *plans;
  
    // History threads don't have a thread plan, but they do ask get asked to
    // describe themselves, which usually involves pulling out the stop reason.
    // That in turn will check for a completed plan on the ThreadPlanStack.
    // Instead of special-casing at that point, we return a Stack with a
    // ThreadPlanNull as its base plan.  That will give the right answers to the
    // queries GetDescription makes, and only assert if you try to run the thread.
    if (!m_null_plan_stack_up)
      m_null_plan_stack_up = std::make_unique<ThreadPlanStack>(*this, true);
    return *(m_null_plan_stack_up.get());
  }
  
  void Thread::PushPlan(ThreadPlanSP thread_plan_sp) {
    assert(thread_plan_sp && "Don't push an empty thread plan.");
  
    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
    if (log) {
      StreamString s;
      thread_plan_sp->GetDescription(&s, lldb::eDescriptionLevelFull);
      LLDB_LOGF(log, "Thread::PushPlan(0x%p): \"%s\", tid = 0x%4.4" PRIx64 ".",
                static_cast<void *>(this), s.GetData(),
                thread_plan_sp->GetThread().GetID());
    }
    
    GetPlans().PushPlan(std::move(thread_plan_sp));
  }
  
  void Thread::PopPlan() {
    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
    ThreadPlanSP popped_plan_sp = GetPlans().PopPlan();
    if (log) {
      LLDB_LOGF(log, "Popping plan: \"%s\", tid = 0x%4.4" PRIx64 ".",
                popped_plan_sp->GetName(), popped_plan_sp->GetThread().GetID());
    }
  }
  
  void Thread::DiscardPlan() {
    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
    ThreadPlanSP discarded_plan_sp = GetPlans().PopPlan();
  
    LLDB_LOGF(log, "Discarding plan: \"%s\", tid = 0x%4.4" PRIx64 ".",
              discarded_plan_sp->GetName(), 
              discarded_plan_sp->GetThread().GetID());
  }
  
  void Thread::AutoCompleteThreadPlans(CompletionRequest &request) const {
    const ThreadPlanStack &plans = GetPlans();
    if (!plans.AnyPlans())
      return;
  
    // Iterate from the second plan (index: 1) to skip the base plan.
    ThreadPlanSP p;
    uint32_t i = 1;
    while (p = plans.GetPlanByIndex(i, false)) {
      StreamString strm;
      p->GetDescription(&strm, eDescriptionLevelInitial);
      request.TryCompleteCurrentArg(std::to_string(i), strm.GetString());
      i++;
    }
  }
  
  ThreadPlan *Thread::GetCurrentPlan() const {
    return GetPlans().GetCurrentPlan().get();
  }
  
  ValueObjectSP Thread::GetReturnValueObject(bool *is_swift_error_value) {
    if (is_swift_error_value)
      *is_swift_error_value = false;
      
    bool is_error;
    ValueObjectSP return_valobj_sp = GetPlans().GetReturnValueObject(is_error);
    if (return_valobj_sp) {
      if (is_swift_error_value)
        *is_swift_error_value = is_error;
      return return_valobj_sp;
    }
    return ValueObjectSP();
  }
  
  ThreadPlanSP Thread::GetCompletedPlan() const {
    return GetPlans().GetCompletedPlan();
  }
  
  ExpressionVariableSP Thread::GetExpressionVariable() const {
    return GetPlans().GetExpressionVariable();
  }
  
  bool Thread::IsThreadPlanDone(ThreadPlan *plan) const {
    return GetPlans().IsPlanDone(plan);
  }
  
  bool Thread::WasThreadPlanDiscarded(ThreadPlan *plan) const {
    return GetPlans().WasPlanDiscarded(plan);
  }
  
  bool Thread::CompletedPlanOverridesBreakpoint() const {
    return GetPlans().AnyCompletedPlans();
  }
  
  ThreadPlan *Thread::GetPreviousPlan(ThreadPlan *current_plan) const{
    return GetPlans().GetPreviousPlan(current_plan);
  }
  
  Status Thread::QueueThreadPlan(ThreadPlanSP &thread_plan_sp,
                                 bool abort_other_plans) {
    Status status;
    StreamString s;
    if (!thread_plan_sp->ValidatePlan(&s)) {
      DiscardThreadPlansUpToPlan(thread_plan_sp);
      thread_plan_sp.reset();
      status.SetErrorString(s.GetString());
      return status;
    }
  
    if (abort_other_plans)
      DiscardThreadPlans(true);
  
    PushPlan(thread_plan_sp);
  
    // This seems a little funny, but I don't want to have to split up the
    // constructor and the DidPush in the scripted plan, that seems annoying.
    // That means the constructor has to be in DidPush. So I have to validate the
    // plan AFTER pushing it, and then take it off again...
    if (!thread_plan_sp->ValidatePlan(&s)) {
      DiscardThreadPlansUpToPlan(thread_plan_sp);
      thread_plan_sp.reset();
      status.SetErrorString(s.GetString());
      return status;
    }
  
    return status;
  }
  
  void Thread::EnableTracer(bool value, bool single_stepping) {
    GetPlans().EnableTracer(value, single_stepping);
  }
  
  void Thread::SetTracer(lldb::ThreadPlanTracerSP &tracer_sp) {
    GetPlans().SetTracer(tracer_sp);
  }
  
  bool Thread::DiscardUserThreadPlansUpToIndex(uint32_t plan_index) {
    // Count the user thread plans from the back end to get the number of the one
    // we want to discard:
  
    ThreadPlan *up_to_plan_ptr = GetPlans().GetPlanByIndex(plan_index).get();
    if (up_to_plan_ptr == nullptr)
      return false;
  
    DiscardThreadPlansUpToPlan(up_to_plan_ptr);
    return true;
  }
  
  void Thread::DiscardThreadPlansUpToPlan(lldb::ThreadPlanSP &up_to_plan_sp) {
    DiscardThreadPlansUpToPlan(up_to_plan_sp.get());
  }
  
  void Thread::DiscardThreadPlansUpToPlan(ThreadPlan *up_to_plan_ptr) {
    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
    LLDB_LOGF(log,
              "Discarding thread plans for thread tid = 0x%4.4" PRIx64
              ", up to %p",
              GetID(), static_cast<void *>(up_to_plan_ptr));
    GetPlans().DiscardPlansUpToPlan(up_to_plan_ptr);
  }
  
  void Thread::DiscardThreadPlans(bool force) {
    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
    if (log) {
      LLDB_LOGF(log,
                "Discarding thread plans for thread (tid = 0x%4.4" PRIx64
                ", force %d)",
                GetID(), force);
    }
  
    if (force) {
      GetPlans().DiscardAllPlans();
      return;
    }
    GetPlans().DiscardConsultingMasterPlans();
  }
  
  Status Thread::UnwindInnermostExpression() {
    Status error;
    ThreadPlan *innermost_expr_plan = GetPlans().GetInnermostExpression();
    if (!innermost_expr_plan) {
      error.SetErrorString("No expressions currently active on this thread");
      return error;
    }  
    DiscardThreadPlansUpToPlan(innermost_expr_plan);
    return error;
  }
  
  ThreadPlanSP Thread::QueueFundamentalPlan(bool abort_other_plans) {
    ThreadPlanSP thread_plan_sp(new ThreadPlanBase(*this));
    QueueThreadPlan(thread_plan_sp, abort_other_plans);
    return thread_plan_sp;
  }
  
  ThreadPlanSP Thread::QueueThreadPlanForStepSingleInstruction(
      bool step_over, bool abort_other_plans, bool stop_other_threads,
      Status &status) {
    ThreadPlanSP thread_plan_sp(new ThreadPlanStepInstruction(
        *this, step_over, stop_other_threads, eVoteNoOpinion, eVoteNoOpinion));
    status = QueueThreadPlan(thread_plan_sp, abort_other_plans);
    return thread_plan_sp;
  }
  
  ThreadPlanSP Thread::QueueThreadPlanForStepOverRange(
      bool abort_other_plans, const AddressRange &range,
      const SymbolContext &addr_context, lldb::RunMode stop_other_threads,
      Status &status, LazyBool step_out_avoids_code_withoug_debug_info) {
    ThreadPlanSP thread_plan_sp;
    thread_plan_sp = std::make_shared<ThreadPlanStepOverRange>(
        *this, range, addr_context, stop_other_threads,
        step_out_avoids_code_withoug_debug_info);
  
    status = QueueThreadPlan(thread_plan_sp, abort_other_plans);
    return thread_plan_sp;
  }
  
  // Call the QueueThreadPlanForStepOverRange method which takes an address
  // range.
  ThreadPlanSP Thread::QueueThreadPlanForStepOverRange(
      bool abort_other_plans, const LineEntry &line_entry,
      const SymbolContext &addr_context, lldb::RunMode stop_other_threads,
      Status &status, LazyBool step_out_avoids_code_withoug_debug_info) {
    const bool include_inlined_functions = true;
    auto address_range =
        line_entry.GetSameLineContiguousAddressRange(include_inlined_functions);
    return QueueThreadPlanForStepOverRange(
        abort_other_plans, address_range, addr_context, stop_other_threads,
        status, step_out_avoids_code_withoug_debug_info);
  }
  
  ThreadPlanSP Thread::QueueThreadPlanForStepInRange(
      bool abort_other_plans, const AddressRange &range,
      const SymbolContext &addr_context, const char *step_in_target,
      lldb::RunMode stop_other_threads, Status &status,
      LazyBool step_in_avoids_code_without_debug_info,
      LazyBool step_out_avoids_code_without_debug_info) {
    ThreadPlanSP thread_plan_sp(
        new ThreadPlanStepInRange(*this, range, addr_context, stop_other_threads,
                                  step_in_avoids_code_without_debug_info,
                                  step_out_avoids_code_without_debug_info));
    ThreadPlanStepInRange *plan =
        static_cast<ThreadPlanStepInRange *>(thread_plan_sp.get());
  
    if (step_in_target)
      plan->SetStepInTarget(step_in_target);
  
    status = QueueThreadPlan(thread_plan_sp, abort_other_plans);
    return thread_plan_sp;
  }
  
  ThreadPlanSP Thread::QueueThreadPlanForStepInRangeNoShouldStop(
      bool abort_other_plans, const AddressRange &range,
      const SymbolContext &addr_context, const char *step_in_target,
      lldb::RunMode stop_other_threads, Status &status,
      LazyBool step_in_avoids_code_without_debug_info,
      LazyBool step_out_avoids_code_without_debug_info) {
    ThreadPlanSP thread_plan_sp(
        new ThreadPlanStepInRange(*this, range, addr_context, stop_other_threads,
                                  step_in_avoids_code_without_debug_info,
                                  step_out_avoids_code_without_debug_info));
    ThreadPlanStepInRange *plan =
        static_cast<ThreadPlanStepInRange *>(thread_plan_sp.get());
  
    if (step_in_target)
      plan->SetStepInTarget(step_in_target);
  
    plan->ClearShouldStopHereCallbacks();
  
    status = QueueThreadPlan(thread_plan_sp, abort_other_plans);
    return thread_plan_sp;
  }
  
  // Call the QueueThreadPlanForStepInRange method which takes an address range.
  ThreadPlanSP Thread::QueueThreadPlanForStepInRange(
      bool abort_other_plans, const LineEntry &line_entry,
      const SymbolContext &addr_context, const char *step_in_target,
      lldb::RunMode stop_other_threads, Status &status,
      LazyBool step_in_avoids_code_without_debug_info,
      LazyBool step_out_avoids_code_without_debug_info) {
    const bool include_inlined_functions = false;
    return QueueThreadPlanForStepInRange(
        abort_other_plans,
        line_entry.GetSameLineContiguousAddressRange(include_inlined_functions),
        addr_context, step_in_target, stop_other_threads, status,
        step_in_avoids_code_without_debug_info,
        step_out_avoids_code_without_debug_info);
  }
  
  ThreadPlanSP Thread::QueueThreadPlanForStepOut(
      bool abort_other_plans, SymbolContext *addr_context, bool first_insn,
      bool stop_other_threads, Vote stop_vote, Vote run_vote, uint32_t frame_idx,
      Status &status, LazyBool step_out_avoids_code_without_debug_info) {
    ThreadPlanSP thread_plan_sp(new ThreadPlanStepOut(
        *this, addr_context, first_insn, stop_other_threads, stop_vote, run_vote,
        frame_idx, step_out_avoids_code_without_debug_info));
  
    status = QueueThreadPlan(thread_plan_sp, abort_other_plans);
    return thread_plan_sp;
  }
  
  ThreadPlanSP Thread::QueueThreadPlanForStepOutNoShouldStop(
      bool abort_other_plans, SymbolContext *addr_context, bool first_insn,
      bool stop_other_threads, Vote stop_vote, Vote run_vote, uint32_t frame_idx,
      Status &status, bool continue_to_next_branch) {
    const bool calculate_return_value =
        false; // No need to calculate the return value here.
    ThreadPlanSP thread_plan_sp(new ThreadPlanStepOut(
        *this, addr_context, first_insn, stop_other_threads, stop_vote, run_vote,
        frame_idx, eLazyBoolNo, continue_to_next_branch, calculate_return_value));
  
    ThreadPlanStepOut *new_plan =
        static_cast<ThreadPlanStepOut *>(thread_plan_sp.get());
    new_plan->ClearShouldStopHereCallbacks();
  
    status = QueueThreadPlan(thread_plan_sp, abort_other_plans);
    return thread_plan_sp;
  }
  
  ThreadPlanSP Thread::QueueThreadPlanForStepThrough(StackID &return_stack_id,
                                                     bool abort_other_plans,
                                                     bool stop_other_threads,
                                                     Status &status) {
    ThreadPlanSP thread_plan_sp(
        new ThreadPlanStepThrough(*this, return_stack_id, stop_other_threads));
    if (!thread_plan_sp || !thread_plan_sp->ValidatePlan(nullptr))
      return ThreadPlanSP();
  
    status = QueueThreadPlan(thread_plan_sp, abort_other_plans);
    return thread_plan_sp;
  }
  
  ThreadPlanSP Thread::QueueThreadPlanForRunToAddress(bool abort_other_plans,
                                                      Address &target_addr,
                                                      bool stop_other_threads,
                                                      Status &status) {
    ThreadPlanSP thread_plan_sp(
        new ThreadPlanRunToAddress(*this, target_addr, stop_other_threads));
  
    status = QueueThreadPlan(thread_plan_sp, abort_other_plans);
    return thread_plan_sp;
  }
  
  ThreadPlanSP Thread::QueueThreadPlanForStepUntil(
      bool abort_other_plans, lldb::addr_t *address_list, size_t num_addresses,
      bool stop_other_threads, uint32_t frame_idx, Status &status) {
    ThreadPlanSP thread_plan_sp(new ThreadPlanStepUntil(
        *this, address_list, num_addresses, stop_other_threads, frame_idx));
  
    status = QueueThreadPlan(thread_plan_sp, abort_other_plans);
    return thread_plan_sp;
  }
  
  lldb::ThreadPlanSP Thread::QueueThreadPlanForStepScripted(
      bool abort_other_plans, const char *class_name, 
      StructuredData::ObjectSP extra_args_sp,  bool stop_other_threads,
      Status &status) {
      
    StructuredDataImpl *extra_args_impl = nullptr; 
    if (extra_args_sp) {
      extra_args_impl = new StructuredDataImpl();
      extra_args_impl->SetObjectSP(extra_args_sp);
    }
  
    ThreadPlanSP thread_plan_sp(new ThreadPlanPython(*this, class_name, 
                                                     extra_args_impl));
    thread_plan_sp->SetStopOthers(stop_other_threads);
    status = QueueThreadPlan(thread_plan_sp, abort_other_plans);
    return thread_plan_sp;
  }
  
  uint32_t Thread::GetIndexID() const { return m_index_id; }
  
  TargetSP Thread::CalculateTarget() {
    TargetSP target_sp;
    ProcessSP process_sp(GetProcess());
    if (process_sp)
      target_sp = process_sp->CalculateTarget();
    return target_sp;
  }
  
  ProcessSP Thread::CalculateProcess() { return GetProcess(); }
  
  ThreadSP Thread::CalculateThread() { return shared_from_this(); }
  
  StackFrameSP Thread::CalculateStackFrame() { return StackFrameSP(); }
  
  void Thread::CalculateExecutionContext(ExecutionContext &exe_ctx) {
    exe_ctx.SetContext(shared_from_this());
  }
  
  StackFrameListSP Thread::GetStackFrameList() {
    std::lock_guard<std::recursive_mutex> guard(m_frame_mutex);
  
    if (!m_curr_frames_sp)
      m_curr_frames_sp =
          std::make_shared<StackFrameList>(*this, m_prev_frames_sp, true);
  
    return m_curr_frames_sp;
  }
  
  void Thread::ClearStackFrames() {
    std::lock_guard<std::recursive_mutex> guard(m_frame_mutex);
  
    GetUnwinder().Clear();
  
    // Only store away the old "reference" StackFrameList if we got all its
    // frames:
    // FIXME: At some point we can try to splice in the frames we have fetched
    // into
    // the new frame as we make it, but let's not try that now.
    if (m_curr_frames_sp && m_curr_frames_sp->GetAllFramesFetched())
      m_prev_frames_sp.swap(m_curr_frames_sp);
    m_curr_frames_sp.reset();
  
    m_extended_info.reset();
    m_extended_info_fetched = false;
  }
  
  lldb::StackFrameSP Thread::GetFrameWithConcreteFrameIndex(uint32_t unwind_idx) {
    return GetStackFrameList()->GetFrameWithConcreteFrameIndex(unwind_idx);
  }
  
  Status Thread::ReturnFromFrameWithIndex(uint32_t frame_idx,
                                          lldb::ValueObjectSP return_value_sp,
                                          bool broadcast) {
    StackFrameSP frame_sp = GetStackFrameAtIndex(frame_idx);
    Status return_error;
  
    if (!frame_sp) {
      return_error.SetErrorStringWithFormat(
          "Could not find frame with index %d in thread 0x%" PRIx64 ".",
          frame_idx, GetID());
    }
  
    return ReturnFromFrame(frame_sp, return_value_sp, broadcast);
  }
  
  Status Thread::ReturnFromFrame(lldb::StackFrameSP frame_sp,
                                 lldb::ValueObjectSP return_value_sp,
                                 bool broadcast) {
    Status return_error;
  
    if (!frame_sp) {
      return_error.SetErrorString("Can't return to a null frame.");
      return return_error;
    }
  
    Thread *thread = frame_sp->GetThread().get();
    uint32_t older_frame_idx = frame_sp->GetFrameIndex() + 1;
    StackFrameSP older_frame_sp = thread->GetStackFrameAtIndex(older_frame_idx);
    if (!older_frame_sp) {
      return_error.SetErrorString("No older frame to return to.");
      return return_error;
    }
  
    if (return_value_sp) {
      lldb::ABISP abi = thread->GetProcess()->GetABI();
      if (!abi) {
        return_error.SetErrorString("Could not find ABI to set return value.");
        return return_error;
      }
      SymbolContext sc = frame_sp->GetSymbolContext(eSymbolContextFunction);
  
      // FIXME: ValueObject::Cast doesn't currently work correctly, at least not
      // for scalars.
      // Turn that back on when that works.
      if (/* DISABLES CODE */ (false) && sc.function != nullptr) {
        Type *function_type = sc.function->GetType();
        if (function_type) {
          CompilerType return_type =
              sc.function->GetCompilerType().GetFunctionReturnType();
          if (return_type) {
            StreamString s;
            return_type.DumpTypeDescription(&s);
            ValueObjectSP cast_value_sp = return_value_sp->Cast(return_type);
            if (cast_value_sp) {
              cast_value_sp->SetFormat(eFormatHex);
              return_value_sp = cast_value_sp;
            }
          }
        }
      }
  
      return_error = abi->SetReturnValueObject(older_frame_sp, return_value_sp);
      if (!return_error.Success())
        return return_error;
    }
  
    // Now write the return registers for the chosen frame: Note, we can't use
    // ReadAllRegisterValues->WriteAllRegisterValues, since the read & write cook
    // their data
  
    StackFrameSP youngest_frame_sp = thread->GetStackFrameAtIndex(0);
    if (youngest_frame_sp) {
      lldb::RegisterContextSP reg_ctx_sp(youngest_frame_sp->GetRegisterContext());
      if (reg_ctx_sp) {
        bool copy_success = reg_ctx_sp->CopyFromRegisterContext(
            older_frame_sp->GetRegisterContext());
        if (copy_success) {
          thread->DiscardThreadPlans(true);
          thread->ClearStackFrames();
          if (broadcast && EventTypeHasListeners(eBroadcastBitStackChanged))
            BroadcastEvent(eBroadcastBitStackChanged,
                           new ThreadEventData(this->shared_from_this()));
        } else {
          return_error.SetErrorString("Could not reset register values.");
        }
      } else {
        return_error.SetErrorString("Frame has no register context.");
      }
    } else {
      return_error.SetErrorString("Returned past top frame.");
    }
    return return_error;
  }
  
  static void DumpAddressList(Stream &s, const std::vector<Address> &list,
                              ExecutionContextScope *exe_scope) {
    for (size_t n = 0; n < list.size(); n++) {
      s << "\t";
      list[n].Dump(&s, exe_scope, Address::DumpStyleResolvedDescription,
                   Address::DumpStyleSectionNameOffset);
      s << "\n";
    }
  }
  
  Status Thread::JumpToLine(const FileSpec &file, uint32_t line,
                            bool can_leave_function, std::string *warnings) {
    ExecutionContext exe_ctx(GetStackFrameAtIndex(0));
    Target *target = exe_ctx.GetTargetPtr();
    TargetSP target_sp = exe_ctx.GetTargetSP();
    RegisterContext *reg_ctx = exe_ctx.GetRegisterContext();
    StackFrame *frame = exe_ctx.GetFramePtr();
    const SymbolContext &sc = frame->GetSymbolContext(eSymbolContextFunction);
  
    // Find candidate locations.
    std::vector<Address> candidates, within_function, outside_function;
    target->GetImages().FindAddressesForLine(target_sp, file, line, sc.function,
                                             within_function, outside_function);
  
    // If possible, we try and stay within the current function. Within a
    // function, we accept multiple locations (optimized code may do this,
    // there's no solution here so we do the best we can). However if we're
    // trying to leave the function, we don't know how to pick the right
    // location, so if there's more than one then we bail.
    if (!within_function.empty())
      candidates = within_function;
    else if (outside_function.size() == 1 && can_leave_function)
      candidates = outside_function;
  
    // Check if we got anything.
    if (candidates.empty()) {
      if (outside_function.empty()) {
        return Status("Cannot locate an address for %s:%i.",
                      file.GetFilename().AsCString(), line);
      } else if (outside_function.size() == 1) {
        return Status("%s:%i is outside the current function.",
                      file.GetFilename().AsCString(), line);
      } else {
        StreamString sstr;
        DumpAddressList(sstr, outside_function, target);
        return Status("%s:%i has multiple candidate locations:\n%s",
                      file.GetFilename().AsCString(), line, sstr.GetData());
      }
    }
  
    // Accept the first location, warn about any others.
    Address dest = candidates[0];
    if (warnings && candidates.size() > 1) {
      StreamString sstr;
      sstr.Printf("%s:%i appears multiple times in this function, selecting the "
                  "first location:\n",
                  file.GetFilename().AsCString(), line);
      DumpAddressList(sstr, candidates, target);
      *warnings = std::string(sstr.GetString());
    }
  
    if (!reg_ctx->SetPC(dest))
      return Status("Cannot change PC to target address.");
  
    return Status();
  }
  
  void Thread::DumpUsingSettingsFormat(Stream &strm, uint32_t frame_idx,
                                       bool stop_format) {
    ExecutionContext exe_ctx(shared_from_this());
    Process *process = exe_ctx.GetProcessPtr();
    if (process == nullptr)
      return;
  
    StackFrameSP frame_sp;
    SymbolContext frame_sc;
    if (frame_idx != LLDB_INVALID_FRAME_ID) {
      frame_sp = GetStackFrameAtIndex(frame_idx);
      if (frame_sp) {
        exe_ctx.SetFrameSP(frame_sp);
        frame_sc = frame_sp->GetSymbolContext(eSymbolContextEverything);
      }
    }
  
    const FormatEntity::Entry *thread_format;
    if (stop_format)
      thread_format = exe_ctx.GetTargetRef().GetDebugger().GetThreadStopFormat();
    else
      thread_format = exe_ctx.GetTargetRef().GetDebugger().GetThreadFormat();
  
    assert(thread_format);
  
    FormatEntity::Format(*thread_format, strm, frame_sp ? &frame_sc : nullptr,
                         &exe_ctx, nullptr, nullptr, false, false);
  }
  
  void Thread::SettingsInitialize() {}
  
  void Thread::SettingsTerminate() {}
  
  lldb::addr_t Thread::GetThreadPointer() { return LLDB_INVALID_ADDRESS; }
  
  addr_t Thread::GetThreadLocalData(const ModuleSP module,
                                    lldb::addr_t tls_file_addr) {
    // The default implementation is to ask the dynamic loader for it. This can
    // be overridden for specific platforms.
    DynamicLoader *loader = GetProcess()->GetDynamicLoader();
    if (loader)
      return loader->GetThreadLocalData(module, shared_from_this(),
                                        tls_file_addr);
    else
      return LLDB_INVALID_ADDRESS;
  }
  
  bool Thread::SafeToCallFunctions() {
    Process *process = GetProcess().get();
    if (process) {
      SystemRuntime *runtime = process->GetSystemRuntime();
      if (runtime) {
        return runtime->SafeToCallFunctionsOnThisThread(shared_from_this());
      }
    }
    return true;
  }
  
  lldb::StackFrameSP
  Thread::GetStackFrameSPForStackFramePtr(StackFrame *stack_frame_ptr) {
    return GetStackFrameList()->GetStackFrameSPForStackFramePtr(stack_frame_ptr);
  }
  
  const char *Thread::StopReasonAsCString(lldb::StopReason reason) {
    switch (reason) {
    case eStopReasonInvalid:
      return "invalid";
    case eStopReasonNone:
      return "none";
    case eStopReasonTrace:
      return "trace";
    case eStopReasonBreakpoint:
      return "breakpoint";
    case eStopReasonWatchpoint:
      return "watchpoint";
    case eStopReasonSignal:
      return "signal";
    case eStopReasonException:
      return "exception";
    case eStopReasonExec:
      return "exec";
    case eStopReasonPlanComplete:
      return "plan complete";
    case eStopReasonThreadExiting:
      return "thread exiting";
    case eStopReasonInstrumentation:
      return "instrumentation break";
    }
  
    static char unknown_state_string[64];
    snprintf(unknown_state_string, sizeof(unknown_state_string),
             "StopReason = %i", reason);
    return unknown_state_string;
  }
  
  const char *Thread::RunModeAsCString(lldb::RunMode mode) {
    switch (mode) {
    case eOnlyThisThread:
      return "only this thread";
    case eAllThreads:
      return "all threads";
    case eOnlyDuringStepping:
      return "only during stepping";
    }
  
    static char unknown_state_string[64];
    snprintf(unknown_state_string, sizeof(unknown_state_string), "RunMode = %i",
             mode);
    return unknown_state_string;
  }
  
  size_t Thread::GetStatus(Stream &strm, uint32_t start_frame,
                           uint32_t num_frames, uint32_t num_frames_with_source,
                           bool stop_format, bool only_stacks) {
  
    if (!only_stacks) {
      ExecutionContext exe_ctx(shared_from_this());
      Target *target = exe_ctx.GetTargetPtr();
      Process *process = exe_ctx.GetProcessPtr();
      strm.Indent();
      bool is_selected = false;
      if (process) {
        if (process->GetThreadList().GetSelectedThread().get() == this)
          is_selected = true;
      }
      strm.Printf("%c ", is_selected ? '*' : ' ');
      if (target && target->GetDebugger().GetUseExternalEditor()) {
        StackFrameSP frame_sp = GetStackFrameAtIndex(start_frame);
        if (frame_sp) {
          SymbolContext frame_sc(
              frame_sp->GetSymbolContext(eSymbolContextLineEntry));
          if (frame_sc.line_entry.line != 0 && frame_sc.line_entry.file) {
            Host::OpenFileInExternalEditor(frame_sc.line_entry.file,
                                           frame_sc.line_entry.line);
          }
        }
      }
  
      DumpUsingSettingsFormat(strm, start_frame, stop_format);
    }
  
    size_t num_frames_shown = 0;
    if (num_frames > 0) {
      strm.IndentMore();
  
      const bool show_frame_info = true;
      const bool show_frame_unique = only_stacks;
      const char *selected_frame_marker = nullptr;
      if (num_frames == 1 || only_stacks ||
          (GetID() != GetProcess()->GetThreadList().GetSelectedThread()->GetID()))
        strm.IndentMore();
      else
        selected_frame_marker = "* ";
  
      num_frames_shown = GetStackFrameList()->GetStatus(
          strm, start_frame, num_frames, show_frame_info, num_frames_with_source,
          show_frame_unique, selected_frame_marker);
      if (num_frames == 1)
        strm.IndentLess();
      strm.IndentLess();
    }
    return num_frames_shown;
  }
  
  bool Thread::GetDescription(Stream &strm, lldb::DescriptionLevel level,
                              bool print_json_thread, bool print_json_stopinfo) {
    const bool stop_format = false;
    DumpUsingSettingsFormat(strm, 0, stop_format);
    strm.Printf("\n");
  
    StructuredData::ObjectSP thread_info = GetExtendedInfo();
  
    if (print_json_thread || print_json_stopinfo) {
      if (thread_info && print_json_thread) {
        thread_info->Dump(strm);
        strm.Printf("\n");
      }
  
      if (print_json_stopinfo && m_stop_info_sp) {
        StructuredData::ObjectSP stop_info = m_stop_info_sp->GetExtendedInfo();
        if (stop_info) {
          stop_info->Dump(strm);
          strm.Printf("\n");
        }
      }
  
      return true;
    }
  
    if (thread_info) {
      StructuredData::ObjectSP activity =
          thread_info->GetObjectForDotSeparatedPath("activity");
      StructuredData::ObjectSP breadcrumb =
          thread_info->GetObjectForDotSeparatedPath("breadcrumb");
      StructuredData::ObjectSP messages =
          thread_info->GetObjectForDotSeparatedPath("trace_messages");
  
      bool printed_activity = false;
      if (activity && activity->GetType() == eStructuredDataTypeDictionary) {
        StructuredData::Dictionary *activity_dict = activity->GetAsDictionary();
        StructuredData::ObjectSP id = activity_dict->GetValueForKey("id");
        StructuredData::ObjectSP name = activity_dict->GetValueForKey("name");
        if (name && name->GetType() == eStructuredDataTypeString && id &&
            id->GetType() == eStructuredDataTypeInteger) {
          strm.Format("  Activity '{0}', {1:x}\n",
                      name->GetAsString()->GetValue(),
                      id->GetAsInteger()->GetValue());
        }
        printed_activity = true;
      }
      bool printed_breadcrumb = false;
      if (breadcrumb && breadcrumb->GetType() == eStructuredDataTypeDictionary) {
        if (printed_activity)
          strm.Printf("\n");
        StructuredData::Dictionary *breadcrumb_dict =
            breadcrumb->GetAsDictionary();
        StructuredData::ObjectSP breadcrumb_text =
            breadcrumb_dict->GetValueForKey("name");
        if (breadcrumb_text &&
            breadcrumb_text->GetType() == eStructuredDataTypeString) {
          strm.Format("  Current Breadcrumb: {0}\n",
                      breadcrumb_text->GetAsString()->GetValue());
        }
        printed_breadcrumb = true;
      }
      if (messages && messages->GetType() == eStructuredDataTypeArray) {
        if (printed_breadcrumb)
          strm.Printf("\n");
        StructuredData::Array *messages_array = messages->GetAsArray();
        const size_t msg_count = messages_array->GetSize();
        if (msg_count > 0) {
          strm.Printf("  %zu trace messages:\n", msg_count);
          for (size_t i = 0; i < msg_count; i++) {
            StructuredData::ObjectSP message = messages_array->GetItemAtIndex(i);
            if (message && message->GetType() == eStructuredDataTypeDictionary) {
              StructuredData::Dictionary *message_dict =
                  message->GetAsDictionary();
              StructuredData::ObjectSP message_text =
                  message_dict->GetValueForKey("message");
              if (message_text &&
                  message_text->GetType() == eStructuredDataTypeString) {
                strm.Format("    {0}\n", message_text->GetAsString()->GetValue());
              }
            }
          }
        }
      }
    }
  
    return true;
  }
  
  size_t Thread::GetStackFrameStatus(Stream &strm, uint32_t first_frame,
                                     uint32_t num_frames, bool show_frame_info,
                                     uint32_t num_frames_with_source) {
    return GetStackFrameList()->GetStatus(
        strm, first_frame, num_frames, show_frame_info, num_frames_with_source);
  }
  
  Unwind &Thread::GetUnwinder() {
    if (!m_unwinder_up)
      m_unwinder_up = std::make_unique<UnwindLLDB>(*this);
    return *m_unwinder_up;
  }
  
  void Thread::Flush() {
    ClearStackFrames();
    m_reg_context_sp.reset();
  }
  
  bool Thread::IsStillAtLastBreakpointHit() {
    // If we are currently stopped at a breakpoint, always return that stopinfo
    // and don't reset it. This allows threads to maintain their breakpoint
    // stopinfo, such as when thread-stepping in multithreaded programs.
    if (m_stop_info_sp) {
      StopReason stop_reason = m_stop_info_sp->GetStopReason();
      if (stop_reason == lldb::eStopReasonBreakpoint) {
        uint64_t value = m_stop_info_sp->GetValue();
        lldb::RegisterContextSP reg_ctx_sp(GetRegisterContext());
        if (reg_ctx_sp) {
          lldb::addr_t pc = reg_ctx_sp->GetPC();
          BreakpointSiteSP bp_site_sp =
              GetProcess()->GetBreakpointSiteList().FindByAddress(pc);
          if (bp_site_sp && static_cast<break_id_t>(value) == bp_site_sp->GetID())
            return true;
        }
      }
    }
    return false;
  }
  
  Status Thread::StepIn(bool source_step,
                        LazyBool step_in_avoids_code_without_debug_info,
                        LazyBool step_out_avoids_code_without_debug_info)
  
  {
    Status error;
    Process *process = GetProcess().get();
    if (StateIsStoppedState(process->GetState(), true)) {
      StackFrameSP frame_sp = GetStackFrameAtIndex(0);
      ThreadPlanSP new_plan_sp;
      const lldb::RunMode run_mode = eOnlyThisThread;
      const bool abort_other_plans = false;
  
      if (source_step && frame_sp && frame_sp->HasDebugInformation()) {
        SymbolContext sc(frame_sp->GetSymbolContext(eSymbolContextEverything));
        new_plan_sp = QueueThreadPlanForStepInRange(
            abort_other_plans, sc.line_entry, sc, nullptr, run_mode, error,
            step_in_avoids_code_without_debug_info,
            step_out_avoids_code_without_debug_info);
      } else {
        new_plan_sp = QueueThreadPlanForStepSingleInstruction(
            false, abort_other_plans, run_mode, error);
      }
  
      new_plan_sp->SetIsMasterPlan(true);
      new_plan_sp->SetOkayToDiscard(false);
  
      // Why do we need to set the current thread by ID here???
      process->GetThreadList().SetSelectedThreadByID(GetID());
      error = process->Resume();
    } else {
      error.SetErrorString("process not stopped");
    }
    return error;
  }
  
  Status Thread::StepOver(bool source_step,
                          LazyBool step_out_avoids_code_without_debug_info) {
    Status error;
    Process *process = GetProcess().get();
    if (StateIsStoppedState(process->GetState(), true)) {
      StackFrameSP frame_sp = GetStackFrameAtIndex(0);
      ThreadPlanSP new_plan_sp;
  
      const lldb::RunMode run_mode = eOnlyThisThread;
      const bool abort_other_plans = false;
  
      if (source_step && frame_sp && frame_sp->HasDebugInformation()) {
        SymbolContext sc(frame_sp->GetSymbolContext(eSymbolContextEverything));
        new_plan_sp = QueueThreadPlanForStepOverRange(
            abort_other_plans, sc.line_entry, sc, run_mode, error,
            step_out_avoids_code_without_debug_info);
      } else {
        new_plan_sp = QueueThreadPlanForStepSingleInstruction(
            true, abort_other_plans, run_mode, error);
      }
  
      new_plan_sp->SetIsMasterPlan(true);
      new_plan_sp->SetOkayToDiscard(false);
  
      // Why do we need to set the current thread by ID here???
      process->GetThreadList().SetSelectedThreadByID(GetID());
      error = process->Resume();
    } else {
      error.SetErrorString("process not stopped");
    }
    return error;
  }
  
  Status Thread::StepOut() {
    Status error;
    Process *process = GetProcess().get();
    if (StateIsStoppedState(process->GetState(), true)) {
      const bool first_instruction = false;
      const bool stop_other_threads = false;
      const bool abort_other_plans = false;
  
      ThreadPlanSP new_plan_sp(QueueThreadPlanForStepOut(
          abort_other_plans, nullptr, first_instruction, stop_other_threads,
          eVoteYes, eVoteNoOpinion, 0, error));
  
      new_plan_sp->SetIsMasterPlan(true);
      new_plan_sp->SetOkayToDiscard(false);
  
      // Why do we need to set the current thread by ID here???
      process->GetThreadList().SetSelectedThreadByID(GetID());
      error = process->Resume();
    } else {
      error.SetErrorString("process not stopped");
    }
    return error;
  }
  
  ValueObjectSP Thread::GetCurrentException() {
    if (auto frame_sp = GetStackFrameAtIndex(0))
      if (auto recognized_frame = frame_sp->GetRecognizedFrame())
        if (auto e = recognized_frame->GetExceptionObject())
          return e;
  
    // NOTE: Even though this behavior is generalized, only ObjC is actually
    // supported at the moment.
    for (LanguageRuntime *runtime : GetProcess()->GetLanguageRuntimes()) {
      if (auto e = runtime->GetExceptionObjectForThread(shared_from_this()))
        return e;
    }
  
    return ValueObjectSP();
  }
  
  ThreadSP Thread::GetCurrentExceptionBacktrace() {
    ValueObjectSP exception = GetCurrentException();
    if (!exception)
      return ThreadSP();
  
    // NOTE: Even though this behavior is generalized, only ObjC is actually
    // supported at the moment.
    for (LanguageRuntime *runtime : GetProcess()->GetLanguageRuntimes()) {
      if (auto bt = runtime->GetBacktraceThreadFromException(exception))
        return bt;
    }
  
    return ThreadSP();
  }
  