lldb/source/Target/ThreadPlanStepUntil.cpp

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

// C Includes
// C++ Includes
// Other libraries and framework includes
// Project includes
#include "lldb/Target/ThreadPlanStepUntil.h"
#include "lldb/Breakpoint/Breakpoint.h"
#include "lldb/Core/Log.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/StopInfo.h"
#include "lldb/Target/Target.h"

using namespace lldb;
using namespace lldb_private;

//----------------------------------------------------------------------
// ThreadPlanStepUntil: Run until we reach a given line number or step out of the current frame
//----------------------------------------------------------------------

ThreadPlanStepUntil::ThreadPlanStepUntil
(
    Thread &thread,
    lldb::addr_t *address_list,
    size_t num_addresses,
    bool stop_others,
    uint32_t frame_idx
) :
    ThreadPlan (ThreadPlan::eKindStepUntil, "Step until", thread, eVoteNoOpinion, eVoteNoOpinion),
    m_step_from_insn (LLDB_INVALID_ADDRESS),
    m_return_bp_id (LLDB_INVALID_BREAK_ID),
    m_return_addr (LLDB_INVALID_ADDRESS),
    m_stepped_out (false),
    m_should_stop (false),
    m_ran_analyze (false),
    m_explains_stop (false),
    m_until_points (),
    m_stop_others (stop_others)
{
    // Stash away our "until" addresses:
    TargetSP target_sp (m_thread.CalculateTarget());

    StackFrameSP frame_sp (m_thread.GetStackFrameAtIndex (frame_idx));
    if (frame_sp)
    {
        m_step_from_insn = frame_sp->GetStackID().GetPC();
        lldb::user_id_t thread_id = m_thread.GetID();

        // Find the return address and set a breakpoint there:
        // FIXME - can we do this more securely if we know first_insn?

        StackFrameSP return_frame_sp (m_thread.GetStackFrameAtIndex(frame_idx + 1));
        if (return_frame_sp)
        {
            // TODO: add inline functionality
            m_return_addr = return_frame_sp->GetStackID().GetPC();
            Breakpoint *return_bp = target_sp->CreateBreakpoint (m_return_addr, true, false).get();
            if (return_bp != nullptr)
            {
                return_bp->SetThreadID(thread_id);
                m_return_bp_id = return_bp->GetID();
                return_bp->SetBreakpointKind ("until-return-backstop");
            }
        }

        m_stack_id = frame_sp->GetStackID();

        // Now set breakpoints on all our return addresses:
        for (size_t i = 0; i < num_addresses; i++)
        {
            Breakpoint *until_bp = target_sp->CreateBreakpoint (address_list[i], true, false).get();
            if (until_bp != nullptr)
            {
                until_bp->SetThreadID(thread_id);
                m_until_points[address_list[i]] = until_bp->GetID();
                until_bp->SetBreakpointKind("until-target");
            }
            else
            {
                m_until_points[address_list[i]] = LLDB_INVALID_BREAK_ID;
            }
        }
    }
}

ThreadPlanStepUntil::~ThreadPlanStepUntil ()
{
    Clear();
}

void
ThreadPlanStepUntil::Clear()
{
    TargetSP target_sp (m_thread.CalculateTarget());
    if (target_sp)
    {
        if (m_return_bp_id != LLDB_INVALID_BREAK_ID)
        {
            target_sp->RemoveBreakpointByID(m_return_bp_id);
            m_return_bp_id = LLDB_INVALID_BREAK_ID;
        }

        until_collection::iterator pos, end = m_until_points.end();
        for (pos = m_until_points.begin(); pos != end; pos++)
        {
            target_sp->RemoveBreakpointByID((*pos).second);
        }
    }
    m_until_points.clear();
}

void
ThreadPlanStepUntil::GetDescription (Stream *s, lldb::DescriptionLevel level)
{
    if (level == lldb::eDescriptionLevelBrief)
    {
        s->Printf ("step until");
        if (m_stepped_out)
            s->Printf (" - stepped out");
    }
    else
    {
        if (m_until_points.size() == 1)
            s->Printf ("Stepping from address 0x%" PRIx64 " until we reach 0x%" PRIx64 " using breakpoint %d",
                       (uint64_t)m_step_from_insn,
                       (uint64_t) (*m_until_points.begin()).first,
                       (*m_until_points.begin()).second);
        else
        {
            until_collection::iterator pos, end = m_until_points.end();
            s->Printf ("Stepping from address 0x%" PRIx64 " until we reach one of:",
                       (uint64_t)m_step_from_insn);
            for (pos = m_until_points.begin(); pos != end; pos++)
            {
                s->Printf ("\n\t0x%" PRIx64 " (bp: %d)", (uint64_t) (*pos).first, (*pos).second);
            }
        }
        s->Printf(" stepped out address is 0x%" PRIx64 ".", (uint64_t) m_return_addr);
    }
}

bool
ThreadPlanStepUntil::ValidatePlan (Stream *error)
{
    if (m_return_bp_id == LLDB_INVALID_BREAK_ID)
        return false;
    else
    {
        until_collection::iterator pos, end = m_until_points.end();
        for (pos = m_until_points.begin(); pos != end; pos++)
        {
            if (!LLDB_BREAK_ID_IS_VALID ((*pos).second))
                return false;
        }
        return true;
    }
}

void
ThreadPlanStepUntil::AnalyzeStop()
{
    if (m_ran_analyze)
        return;
        
    StopInfoSP stop_info_sp = GetPrivateStopInfo ();
    m_should_stop = true;
    m_explains_stop = false;
    
    if (stop_info_sp)
    {
        StopReason reason = stop_info_sp->GetStopReason();

        if (reason == eStopReasonBreakpoint)
        {
            // If this is OUR breakpoint, we're fine, otherwise we don't know why this happened...
            BreakpointSiteSP this_site = m_thread.GetProcess()->GetBreakpointSiteList().FindByID (stop_info_sp->GetValue());
            if (!this_site)
            {
                m_explains_stop = false;
                return;
            }

            if (this_site->IsBreakpointAtThisSite (m_return_bp_id))
            {
                // If we are at our "step out" breakpoint, and the stack depth has shrunk, then
                // this is indeed our stop.
                // If the stack depth has grown, then we've hit our step out breakpoint recursively.
                // If we are the only breakpoint at that location, then we do explain the stop, and
                // we'll just continue.
                // If there was another breakpoint here, then we don't explain the stop, but we won't
                // mark ourselves Completed, because maybe that breakpoint will continue, and then
                // we'll finish the "until".
                bool done;
                StackID cur_frame_zero_id;
                
                done = (m_stack_id < cur_frame_zero_id);
                
                if (done)
                {
                    m_stepped_out = true;
                    SetPlanComplete();
                }
                else
                    m_should_stop = false;

                if (this_site->GetNumberOfOwners() == 1)
                    m_explains_stop = true;
                else
                    m_explains_stop = false;
                return;
            }
            else
            {
                // Check if we've hit one of our "until" breakpoints.
                until_collection::iterator pos, end = m_until_points.end();
                for (pos = m_until_points.begin(); pos != end; pos++)
                {
                    if (this_site->IsBreakpointAtThisSite ((*pos).second))
                    {
                        // If we're at the right stack depth, then we're done.
                        
                        bool done;
                        StackID frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
                        
                        if (frame_zero_id == m_stack_id)
                            done = true;
                        else if (frame_zero_id < m_stack_id)
                            done = false;
                        else
                        {
                            StackFrameSP older_frame_sp = m_thread.GetStackFrameAtIndex(1);
    
                            // But if we can't even unwind one frame we should just get out of here & stop...
                            if (older_frame_sp)
                            {
                                const SymbolContext &older_context 
                                    = older_frame_sp->GetSymbolContext(eSymbolContextEverything);
                                SymbolContext stack_context;
                                m_stack_id.GetSymbolContextScope()->CalculateSymbolContext(&stack_context);
                                
                                done = (older_context == stack_context);
                            }
                            else
                                done = false;
                        }
                        
                        if (done)
                            SetPlanComplete();
                        else
                            m_should_stop = false;

                        // Otherwise we've hit this breakpoint recursively.  If we're the
                        // only breakpoint here, then we do explain the stop, and we'll continue.
                        // If not then we should let higher plans handle this stop.
                        if (this_site->GetNumberOfOwners() == 1)
                            m_explains_stop = true;
                        else
                        {
                            m_should_stop = true;
                            m_explains_stop = false;
                        }
                        return;
                    }
                }
            }
            // If we get here we haven't hit any of our breakpoints, so let the higher
            // plans take care of the stop.
            m_explains_stop = false;
            return;
        }
        else if (IsUsuallyUnexplainedStopReason(reason))
        {
            m_explains_stop = false;
        }
        else
        {
            m_explains_stop = true;
        }
    }
}

bool
ThreadPlanStepUntil::DoPlanExplainsStop (Event *event_ptr)
{
    // We don't explain signals or breakpoints (breakpoints that handle stepping in or
    // out will be handled by a child plan.
    AnalyzeStop();
    return m_explains_stop;
}

bool
ThreadPlanStepUntil::ShouldStop (Event *event_ptr)
{
    // If we've told our self in ExplainsStop that we plan to continue, then
    // do so here.  Otherwise, as long as this thread has stopped for a reason,
    // we will stop.

    StopInfoSP stop_info_sp = GetPrivateStopInfo ();
    if (!stop_info_sp || stop_info_sp->GetStopReason() == eStopReasonNone)
        return false;

    AnalyzeStop();
    return m_should_stop;
}

bool
ThreadPlanStepUntil::StopOthers ()
{
    return m_stop_others;
}

StateType
ThreadPlanStepUntil::GetPlanRunState ()
{
    return eStateRunning;
}

bool
ThreadPlanStepUntil::DoWillResume (StateType resume_state, bool current_plan)
{
    if (current_plan)
    {
        TargetSP target_sp (m_thread.CalculateTarget());
        if (target_sp)
        {
            Breakpoint *return_bp = target_sp->GetBreakpointByID(m_return_bp_id).get();
            if (return_bp != nullptr)
                return_bp->SetEnabled (true);

            until_collection::iterator pos, end = m_until_points.end();
            for (pos = m_until_points.begin(); pos != end; pos++)
            {
                Breakpoint *until_bp = target_sp->GetBreakpointByID((*pos).second).get();
                if (until_bp != nullptr)
                    until_bp->SetEnabled (true);
            }
        }
    }
    
    m_should_stop = true;
    m_ran_analyze = false;
    m_explains_stop = false;
    return true;
}

bool
ThreadPlanStepUntil::WillStop ()
{
    TargetSP target_sp (m_thread.CalculateTarget());
    if (target_sp)
    {
        Breakpoint *return_bp = target_sp->GetBreakpointByID(m_return_bp_id).get();
        if (return_bp != nullptr)
            return_bp->SetEnabled (false);

        until_collection::iterator pos, end = m_until_points.end();
        for (pos = m_until_points.begin(); pos != end; pos++)
        {
            Breakpoint *until_bp = target_sp->GetBreakpointByID((*pos).second).get();
            if (until_bp != nullptr)
                until_bp->SetEnabled (false);
        }
    }
    return true;
}

bool
ThreadPlanStepUntil::MischiefManaged ()
{
    // I'm letting "PlanExplainsStop" do all the work, and just reporting that here.
    bool done = false;
    if (IsPlanComplete())
    {
        Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
        if (log)
            log->Printf("Completed step until plan.");

        Clear();
        done = true;
    }
    if (done)
        ThreadPlan::MischiefManaged ();

    return done;
}