source/Target/Thread.cpp

//===-- Thread.cpp ----------------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "lldb/lldb-private-log.h"
#include "lldb/Breakpoint/BreakpointLocation.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/Stream.h"
#include "lldb/Core/StreamString.h"
#include "lldb/Host/Host.h"
#include "lldb/Target/DynamicLoader.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/StopInfo.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Target/ThreadPlan.h"
#include "lldb/Target/ThreadPlanCallFunction.h"
#include "lldb/Target/ThreadPlanBase.h"
#include "lldb/Target/ThreadPlanStepInstruction.h"
#include "lldb/Target/ThreadPlanStepOut.h"
#include "lldb/Target/ThreadPlanStepOverBreakpoint.h"
#include "lldb/Target/ThreadPlanStepThrough.h"
#include "lldb/Target/ThreadPlanStepInRange.h"
#include "lldb/Target/ThreadPlanStepOverRange.h"
#include "lldb/Target/ThreadPlanRunToAddress.h"
#include "lldb/Target/ThreadPlanStepUntil.h"
#include "lldb/Target/ThreadSpec.h"
#include "lldb/Target/Unwind.h"

using namespace lldb;
using namespace lldb_private;

Thread::Thread (Process &process, lldb::tid_t tid) :
    UserID (tid),
    m_process (process),
    m_public_stop_info_sp (),
    m_actual_stop_info_sp (),
    m_index_id (process.GetNextThreadIndexID ()),
    m_reg_context_sp (),
    m_state (eStateUnloaded),
    m_state_mutex (Mutex::eMutexTypeRecursive),
    m_plan_stack (),
    m_immediate_plan_stack(),
    m_completed_plan_stack(),
    m_curr_frames_ap (),
    m_resume_signal (LLDB_INVALID_SIGNAL_NUMBER),
    m_resume_state (eStateRunning),
    m_unwinder_ap ()

{
    Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_OBJECT);
    if (log)
        log->Printf ("%p Thread::Thread(tid = 0x%4.4x)", this, GetID());

    QueueFundamentalPlan(true);
}


Thread::~Thread()
{
    Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_OBJECT);
    if (log)
        log->Printf ("%p Thread::~Thread(tid = 0x%4.4x)", this, GetID());
}

int
Thread::GetResumeSignal () const
{
    return m_resume_signal;
}

void
Thread::SetResumeSignal (int signal)
{
    m_resume_signal = signal;
}

StateType
Thread::GetResumeState () const
{
    return m_resume_state;
}

void
Thread::SetResumeState (StateType state)
{
    m_resume_state = state;
}

StopInfo *
Thread::GetStopInfo ()
{
    if (m_public_stop_info_sp.get() == NULL)
    {
        ThreadPlanSP plan_sp (GetCompletedPlan());
        if (plan_sp)
            m_public_stop_info_sp = StopInfo::CreateStopReasonWithPlan (plan_sp);
        else
            m_public_stop_info_sp = GetPrivateStopReason ();
    }
    return m_public_stop_info_sp.get();
}

bool
Thread::ThreadStoppedForAReason (void)
{
    return GetPrivateStopReason () != NULL;
}

StateType
Thread::GetState() const
{
    // If any other threads access this we will need a mutex for it
    Mutex::Locker locker(m_state_mutex);
    return m_state;
}

void
Thread::SetState(StateType state)
{
    Mutex::Locker locker(m_state_mutex);
    m_state = state;
}

void
Thread::WillStop()
{
    ThreadPlan *current_plan = GetCurrentPlan();

    // 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::addr_t pc = GetRegisterContext()->GetPC();
        BreakpointSiteSP bp_site_sp = GetProcess().GetBreakpointSiteList().FindByAddress(pc);
        if (bp_site_sp && bp_site_sp->IsEnabled())
        {
            // Note, don't assume there's a ThreadPlanStepOverBreakpoint, the target may not require anything
            // special to step over a breakpoint.
                
            ThreadPlan *cur_plan = GetCurrentPlan();

            if (cur_plan->GetKind() != ThreadPlan::eKindStepOverBreakpoint)
            {
                ThreadPlanStepOverBreakpoint *step_bp_plan = new ThreadPlanStepOverBreakpoint (*this);
                if (step_bp_plan)
                {
                    ThreadPlanSP step_bp_plan_sp;
                    step_bp_plan->SetPrivate (true);

                    if (GetCurrentPlan()->RunState() != eStateStepping)
                    {
                        step_bp_plan->SetAutoContinue(true);
                    }
                    step_bp_plan_sp.reset (step_bp_plan);
                    QueueThreadPlan (step_bp_plan_sp, false);
                }
            }
        }
    }
}

bool
Thread::WillResume (StateType resume_state)
{
    // At this point clear the completed plan stack.
    m_completed_plan_stack.clear();
    m_discarded_plan_stack.clear();

    StopInfo *stop_info = GetPrivateStopReason().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.
    
    ThreadPlan *plan_ptr = GetCurrentPlan();
    plan_ptr->WillResume(resume_state, true);

    while ((plan_ptr = GetPreviousPlan(plan_ptr)) != NULL)
    {
        plan_ptr->WillResume (resume_state, false);
    }
    
    m_public_stop_info_sp.reset();
    m_actual_stop_info_sp.reset();
    return true;
}

void
Thread::DidResume ()
{
    SetResumeSignal (LLDB_INVALID_SIGNAL_NUMBER);
}

bool
Thread::ShouldStop (Event* event_ptr)
{
    ThreadPlan *current_plan = GetCurrentPlan();
    bool should_stop = true;

    Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP);
    if (log)
    {
        StreamString s;
        DumpThreadPlans(&s);
        log->PutCString (s.GetData());
    }

    if (current_plan->PlanExplainsStop())
    {
        bool over_ride_stop = current_plan->ShouldAutoContinue(event_ptr);
        while (1)
        {
            should_stop = current_plan->ShouldStop(event_ptr);
            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 == NULL)
                    {
                        break;
                    }
                }

            }
            else
            {
                break;
            }
        }
        if (over_ride_stop)
            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)) != NULL)
        {
            if (plan_ptr->PlanExplainsStop())
            {
                should_stop = plan_ptr->ShouldStop (event_ptr);
                break;
            }

        }
    }

    return should_stop;
}

Vote
Thread::ShouldReportStop (Event* event_ptr)
{
    StateType thread_state = GetResumeState ();
    Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP);

    if (thread_state == eStateSuspended || thread_state == eStateInvalid)
    {
        if (log)
            log->Printf ("Thread::ShouldReportStop() tid = 0x%4.4x: returning vote %i (state was suspended or invalid)\n", GetID(), eVoteNoOpinion);
        return eVoteNoOpinion;
    }

    if (m_completed_plan_stack.size() > 0)
    {
        // Don't use GetCompletedPlan here, since that suppresses private plans.
        if (log)
            log->Printf ("Thread::ShouldReportStop() tid = 0x%4.4x: returning vote  for complete stack's back plan\n", GetID());
        return m_completed_plan_stack.back()->ShouldReportStop (event_ptr);
    }
    else
    {
        if (log)
            log->Printf ("Thread::ShouldReportStop() tid = 0x%4.4x: returning vote  for current plan\n", GetID());
        return GetCurrentPlan()->ShouldReportStop (event_ptr);
    }
}

Vote
Thread::ShouldReportRun (Event* event_ptr)
{
    StateType thread_state = GetResumeState ();
    if (thread_state == eStateSuspended
            || thread_state == eStateInvalid)
        return eVoteNoOpinion;

    if (m_completed_plan_stack.size() > 0)
    {
        // Don't use GetCompletedPlan here, since that suppresses private plans.
        return m_completed_plan_stack.back()->ShouldReportRun (event_ptr);
    }
    else
        return GetCurrentPlan()->ShouldReportRun (event_ptr);
}

bool
Thread::MatchesSpec (const ThreadSpec *spec)
{
    if (spec == NULL)
        return true;
        
    return spec->ThreadPassesBasicTests(this);    
}

void
Thread::PushPlan (ThreadPlanSP &thread_plan_sp)
{
    if (thread_plan_sp)
    {
        if (thread_plan_sp->IsImmediate())
            m_immediate_plan_stack.push_back (thread_plan_sp);
        else
            m_plan_stack.push_back (thread_plan_sp);

        thread_plan_sp->DidPush();

        Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP);
        if (log)
        {
            StreamString s;
            thread_plan_sp->GetDescription (&s, lldb::eDescriptionLevelFull);
            log->Printf("Pushing plan: \"%s\" for thread: %d immediate: %s.",
                        s.GetData(),
                        thread_plan_sp->GetThread().GetID(),
                        thread_plan_sp->IsImmediate() ? "true" : "false");
        }
    }
}

void
Thread::PopPlan ()
{
    Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP);

    if (!m_immediate_plan_stack.empty())
    {
        ThreadPlanSP &plan = m_immediate_plan_stack.back();
        if (log)
        {
            log->Printf("Popping plan: \"%s\" for thread: %d immediate: true.", plan->GetName(), plan->GetThread().GetID());
        }
        plan->WillPop();
        m_immediate_plan_stack.pop_back();
    }
    else if (m_plan_stack.empty())
        return;
    else
    {
        ThreadPlanSP &plan = m_plan_stack.back();
        if (log)
        {
            log->Printf("Popping plan: \"%s\" for thread: 0x%x immediate: false.", plan->GetName(), plan->GetThread().GetID());
        }
        m_completed_plan_stack.push_back (plan);
        plan->WillPop();
        m_plan_stack.pop_back();
    }
}

void
Thread::DiscardPlan ()
{
    if (m_plan_stack.size() > 1)
    {
        ThreadPlanSP &plan = m_plan_stack.back();
        m_discarded_plan_stack.push_back (plan);
        plan->WillPop();
        m_plan_stack.pop_back();
    }
}

ThreadPlan *
Thread::GetCurrentPlan ()
{
    if (!m_immediate_plan_stack.empty())
        return m_immediate_plan_stack.back().get();
    else if (m_plan_stack.empty())
        return NULL;
    else
        return m_plan_stack.back().get();
}

ThreadPlanSP
Thread::GetCompletedPlan ()
{
    ThreadPlanSP empty_plan_sp;
    if (!m_completed_plan_stack.empty())
    {
        for (int i = m_completed_plan_stack.size() - 1; i >= 0; i--)
        {
            ThreadPlanSP completed_plan_sp;
            completed_plan_sp = m_completed_plan_stack[i];
            if (!completed_plan_sp->GetPrivate ())
            return completed_plan_sp;
        }
    }
    return empty_plan_sp;
}

bool
Thread::IsThreadPlanDone (ThreadPlan *plan)
{
    ThreadPlanSP empty_plan_sp;
    if (!m_completed_plan_stack.empty())
    {
        for (int i = m_completed_plan_stack.size() - 1; i >= 0; i--)
        {
            if (m_completed_plan_stack[i].get() == plan)
                return true;
        }
    }
    return false;
}

bool
Thread::WasThreadPlanDiscarded (ThreadPlan *plan)
{
    ThreadPlanSP empty_plan_sp;
    if (!m_discarded_plan_stack.empty())
    {
        for (int i = m_discarded_plan_stack.size() - 1; i >= 0; i--)
        {
            if (m_discarded_plan_stack[i].get() == plan)
                return true;
        }
    }
    return false;
}

ThreadPlan *
Thread::GetPreviousPlan (ThreadPlan *current_plan)
{
    if (current_plan == NULL)
        return NULL;

    int stack_size = m_completed_plan_stack.size();
    for (int i = stack_size - 1; i > 0; i--)
    {
        if (current_plan == m_completed_plan_stack[i].get())
            return m_completed_plan_stack[i-1].get();
    }

    if (stack_size > 0 && m_completed_plan_stack[0].get() == current_plan)
    {
        if (m_immediate_plan_stack.size() > 0)
            return m_immediate_plan_stack.back().get();
        else if (m_plan_stack.size() > 0)
            return m_plan_stack.back().get();
        else
            return NULL;
    }

    stack_size = m_immediate_plan_stack.size();
    for (int i = stack_size - 1; i > 0; i--)
    {
        if (current_plan == m_immediate_plan_stack[i].get())
            return m_immediate_plan_stack[i-1].get();
    }
    if (stack_size > 0 && m_immediate_plan_stack[0].get() == current_plan)
    {
        if (m_plan_stack.size() > 0)
            return m_plan_stack.back().get();
        else
            return NULL;
    }

    stack_size = m_plan_stack.size();
    for (int i = stack_size - 1; i > 0; i--)
    {
        if (current_plan == m_plan_stack[i].get())
            return m_plan_stack[i-1].get();
    }
    return NULL;
}

void
Thread::QueueThreadPlan (ThreadPlanSP &thread_plan_sp, bool abort_other_plans)
{
    if (abort_other_plans)
       DiscardThreadPlans(true);

    PushPlan (thread_plan_sp);
}

void
Thread::DiscardThreadPlans(bool force)
{
    // FIXME: It is not always safe to just discard plans.  Some, like the step over
    // breakpoint trap can't be discarded in general (though you can if you plan to
    // force a return from a function, for instance.
    // For now I'm just not clearing immediate plans, but I need a way for plans to
    // say they really need to be kept on, and then a way to override that.  Humm...

    Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP);
    if (log)
    {
        log->Printf("Discarding thread plans for thread: 0x%x: force %d.", GetID(), force);
    }

    if (force)
    {
        int stack_size = m_plan_stack.size();
        for (int i = stack_size - 1; i > 0; i--)
        {
            DiscardPlan();
        }
        return;
    }

    while (1)
    {

        int master_plan_idx;
        bool discard;

        // Find the first master plan, see if it wants discarding, and if yes discard up to it.
        for (master_plan_idx = m_plan_stack.size() - 1; master_plan_idx >= 0; master_plan_idx--)
        {
            if (m_plan_stack[master_plan_idx]->IsMasterPlan())
            {
                discard = m_plan_stack[master_plan_idx]->OkayToDiscard();
                break;
            }
        }

        if (discard)
        {
            // First pop all the dependent plans:
            for (int i = m_plan_stack.size() - 1; i > master_plan_idx; i--)
            {

                // FIXME: Do we need a finalize here, or is the rule that "PrepareForStop"
                // for the plan leaves it in a state that it is safe to pop the plan
                // with no more notice?
                DiscardPlan();
            }

            // Now discard the master plan itself.
            // The bottom-most plan never gets discarded.  "OkayToDiscard" for it means
            // discard it's dependent plans, but not it...
            if (master_plan_idx > 0)
            {
                DiscardPlan();
            }
        }
        else
        {
            // If the master plan doesn't want to get discarded, then we're done.
            break;
        }

    }
    // FIXME: What should we do about the immediate plans?
}

ThreadPlan *
Thread::QueueFundamentalPlan (bool abort_other_plans)
{
    ThreadPlanSP thread_plan_sp (new ThreadPlanBase(*this));
    QueueThreadPlan (thread_plan_sp, abort_other_plans);
    return thread_plan_sp.get();
}

ThreadPlan *
Thread::QueueThreadPlanForStepSingleInstruction (bool step_over, bool abort_other_plans, bool stop_other_threads)
{
    ThreadPlanSP thread_plan_sp (new ThreadPlanStepInstruction (*this, step_over, stop_other_threads, eVoteNoOpinion, eVoteNoOpinion));
    QueueThreadPlan (thread_plan_sp, abort_other_plans);
    return thread_plan_sp.get();
}

ThreadPlan *
Thread::QueueThreadPlanForStepRange 
(
    bool abort_other_plans, 
    StepType type, 
    const AddressRange &range, 
    const SymbolContext &addr_context, 
    lldb::RunMode stop_other_threads,
    bool avoid_code_without_debug_info
)
{
    ThreadPlanSP thread_plan_sp;
    if (type == eStepTypeInto)
    {
        ThreadPlanStepInRange *plan = new ThreadPlanStepInRange (*this, range, addr_context, stop_other_threads);
        if (avoid_code_without_debug_info)
            plan->GetFlags().Set (ThreadPlanShouldStopHere::eAvoidNoDebug);
        else
            plan->GetFlags().Clear (ThreadPlanShouldStopHere::eAvoidNoDebug);
        thread_plan_sp.reset (plan);
    }
    else
        thread_plan_sp.reset (new ThreadPlanStepOverRange (*this, range, addr_context, stop_other_threads));

    QueueThreadPlan (thread_plan_sp, abort_other_plans);
    return thread_plan_sp.get();
}


ThreadPlan *
Thread::QueueThreadPlanForStepOverBreakpointPlan (bool abort_other_plans)
{
    ThreadPlanSP thread_plan_sp (new ThreadPlanStepOverBreakpoint (*this));
    QueueThreadPlan (thread_plan_sp, abort_other_plans);
    return thread_plan_sp.get();
}

ThreadPlan *
Thread::QueueThreadPlanForStepOut (bool abort_other_plans, SymbolContext *addr_context, bool first_insn,
        bool stop_other_threads, Vote stop_vote, Vote run_vote)
{
    ThreadPlanSP thread_plan_sp (new ThreadPlanStepOut (*this, addr_context, first_insn, stop_other_threads, stop_vote, run_vote));
    QueueThreadPlan (thread_plan_sp, abort_other_plans);
    return thread_plan_sp.get();
}

ThreadPlan *
Thread::QueueThreadPlanForStepThrough (bool abort_other_plans, bool stop_other_threads)
{
    ThreadPlanSP thread_plan_sp(GetProcess().GetDynamicLoader()->GetStepThroughTrampolinePlan (*this, stop_other_threads));
    if (thread_plan_sp.get() == NULL)
    {
        thread_plan_sp.reset(new ThreadPlanStepThrough (*this, stop_other_threads));
        if (thread_plan_sp && !thread_plan_sp->ValidatePlan (NULL))
            return NULL;
    }
    QueueThreadPlan (thread_plan_sp, abort_other_plans);
    return thread_plan_sp.get();
}

ThreadPlan *
Thread::QueueThreadPlanForCallFunction (bool abort_other_plans,
                                        Address& function,
                                        lldb::addr_t arg,
                                        bool stop_other_threads,
                                        bool discard_on_error)
{
    ThreadPlanSP thread_plan_sp (new ThreadPlanCallFunction (*this, function, arg, stop_other_threads, discard_on_error));
    QueueThreadPlan (thread_plan_sp, abort_other_plans);
    return thread_plan_sp.get();
}

ThreadPlan *
Thread::QueueThreadPlanForCallFunction (bool abort_other_plans,
                                        Address& function,
                                        ValueList &args,
                                        bool stop_other_threads,
                                        bool discard_on_error)
{
    ThreadPlanSP thread_plan_sp (new ThreadPlanCallFunction (*this, function, args, stop_other_threads, discard_on_error));
    QueueThreadPlan (thread_plan_sp, abort_other_plans);
    return thread_plan_sp.get();
}

ThreadPlan *
Thread::QueueThreadPlanForRunToAddress (bool abort_other_plans,
                                        Address &target_addr,
                                        bool stop_other_threads)
{
    ThreadPlanSP thread_plan_sp (new ThreadPlanRunToAddress (*this, target_addr, stop_other_threads));
    QueueThreadPlan (thread_plan_sp, abort_other_plans);
    return thread_plan_sp.get();
}

ThreadPlan *
Thread::QueueThreadPlanForStepUntil (bool abort_other_plans,
                                       lldb::addr_t *address_list,
                                       size_t num_addresses,
                                       bool stop_other_threads)
{
    ThreadPlanSP thread_plan_sp (new ThreadPlanStepUntil (*this, address_list, num_addresses, stop_other_threads));
    QueueThreadPlan (thread_plan_sp, abort_other_plans);
    return thread_plan_sp.get();

}

uint32_t
Thread::GetIndexID () const
{
    return m_index_id;
}

void
Thread::DumpThreadPlans (lldb_private::Stream *s) const
{
    uint32_t stack_size = m_plan_stack.size();
    s->Printf ("Plan Stack for thread #%u: tid = 0x%4.4x - %d elements.\n", GetIndexID(), GetID(), stack_size);
    for (int i = stack_size - 1; i > 0; i--)
    {
        s->Printf ("Element %d: ", i);
        s->IndentMore();
        m_plan_stack[i]->GetDescription (s, eDescriptionLevelFull);
        s->IndentLess();
        s->EOL();
    }

    stack_size = m_immediate_plan_stack.size();
    s->Printf ("Immediate Plan Stack: %d elements.\n", stack_size);
    for (int i = stack_size - 1; i > 0; i--)
    {
        s->Printf ("Element %d: ", i);
        s->IndentMore();
        m_immediate_plan_stack[i]->GetDescription (s, eDescriptionLevelFull);
        s->IndentLess();
        s->EOL();
    }

    stack_size = m_completed_plan_stack.size();
    s->Printf ("Completed Plan Stack: %d elements.\n", stack_size);
    for (int i = stack_size - 1; i > 0; i--)
    {
        s->Printf ("Element %d: ", i);
        s->IndentMore();
        m_completed_plan_stack[i]->GetDescription (s, eDescriptionLevelFull);
        s->IndentLess();
        s->EOL();
    }

    stack_size = m_discarded_plan_stack.size();
    s->Printf ("Discarded Plan Stack: %d elements.\n", stack_size);
    for (int i = stack_size - 1; i > 0; i--)
    {
        s->Printf ("Element %d: ", i);
        s->IndentMore();
        m_discarded_plan_stack[i]->GetDescription (s, eDescriptionLevelFull);
        s->IndentLess();
        s->EOL();
    }

}

Target *
Thread::CalculateTarget ()
{
    return m_process.CalculateTarget();
}

Process *
Thread::CalculateProcess ()
{
    return &m_process;
}

Thread *
Thread::CalculateThread ()
{
    return this;
}

StackFrame *
Thread::CalculateStackFrame ()
{
    return NULL;
}

void
Thread::Calculate (ExecutionContext &exe_ctx)
{
    m_process.Calculate (exe_ctx);
    exe_ctx.thread = this;
    exe_ctx.frame = NULL;
}


StackFrameList &
Thread::GetStackFrameList ()
{
    if (m_curr_frames_ap.get() == NULL)
        m_curr_frames_ap.reset (new StackFrameList (*this, m_prev_frames_sp, true));
    return *m_curr_frames_ap;
}



uint32_t
Thread::GetStackFrameCount()
{
    return GetStackFrameList().GetNumFrames();
}


void
Thread::ClearStackFrames ()
{
    if (m_curr_frames_ap.get() && m_curr_frames_ap->GetNumFrames (false) > 1)
        m_prev_frames_sp.reset (m_curr_frames_ap.release());
    else
        m_curr_frames_ap.release();

//    StackFrameList::Merge (m_curr_frames_ap, m_prev_frames_sp);
//    assert (m_curr_frames_ap.get() == NULL);
}

lldb::StackFrameSP
Thread::GetStackFrameAtIndex (uint32_t idx)
{
    return GetStackFrameList().GetFrameAtIndex(idx);
}

lldb::StackFrameSP
Thread::GetSelectedFrame ()
{
    return GetStackFrameAtIndex (GetStackFrameList().GetSelectedFrameIndex());
}

uint32_t
Thread::SetSelectedFrame (lldb_private::StackFrame *frame)
{
    return GetStackFrameList().SetSelectedFrame(frame);
}

void
Thread::SetSelectedFrameByIndex (uint32_t idx)
{
    GetStackFrameList().SetSelectedFrameByIndex(idx);
}

void
Thread::DumpInfo
(
    Stream &strm,
    bool show_stop_reason,
    bool show_name,
    bool show_queue,
    uint32_t idx
)
{
    strm.Printf("thread #%u: tid = 0x%4.4x", GetIndexID(), GetID());

    if (idx != LLDB_INVALID_INDEX32)
    {
        StackFrameSP frame_sp(GetStackFrameAtIndex (idx));
        if (frame_sp)
        {
            strm.PutCString(", ");
            frame_sp->Dump (&strm, false, false);
        }
    }

    if (show_stop_reason)
    {
        StopInfo *stop_info = GetStopInfo();
        
        if (stop_info)
        {
            const char *stop_description = stop_info->GetDescription();
            if (stop_description)
                strm.Printf (", stop reason = %s", stop_description);
        }
    }

    if (show_name)
    {
        const char *name = GetName();
        if (name && name[0])
            strm.Printf(", name = %s", name);
    }

    if (show_queue)
    {
        const char *queue = GetQueueName();
        if (queue && queue[0])
            strm.Printf(", queue = %s", queue);
    }
}

lldb::ThreadSP
Thread::GetSP ()
{
    return m_process.GetThreadList().GetThreadSPForThreadPtr(this);
}