source/Breakpoint/Breakpoint.cpp

//===-- Breakpoint.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/Core/Address.h"
#include "lldb/Breakpoint/Breakpoint.h"
#include "lldb/Breakpoint/BreakpointLocation.h"
#include "lldb/Breakpoint/BreakpointLocationCollection.h"
#include "lldb/Breakpoint/BreakpointResolver.h"
#include "lldb/Breakpoint/BreakpointResolverFileLine.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ModuleList.h"
#include "lldb/Core/SearchFilter.h"
#include "lldb/Core/Section.h"
#include "lldb/Core/Stream.h"
#include "lldb/Core/StreamString.h"
#include "lldb/Symbol/CompileUnit.h"
#include "lldb/Symbol/Function.h"
#include "lldb/Symbol/SymbolContext.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/ThreadSpec.h"
#include "lldb/lldb-private-log.h"
#include "llvm/Support/Casting.h"

using namespace lldb;
using namespace lldb_private;
using namespace llvm;

const ConstString &
Breakpoint::GetEventIdentifier ()
{
    static ConstString g_identifier("event-identifier.breakpoint.changed");
    return g_identifier;
}

//----------------------------------------------------------------------
// Breakpoint constructor
//----------------------------------------------------------------------
Breakpoint::Breakpoint(Target &target,
                       SearchFilterSP &filter_sp,
                       BreakpointResolverSP &resolver_sp,
                       bool hardware,
                       bool resolve_indirect_symbols) :
    m_being_created(true),
    m_hardware(hardware),
    m_target (target),
    m_filter_sp (filter_sp),
    m_resolver_sp (resolver_sp),
    m_options (),
    m_locations (*this),
    m_resolve_indirect_symbols(resolve_indirect_symbols)
{
    m_being_created = false;
}

//----------------------------------------------------------------------
// Destructor
//----------------------------------------------------------------------
Breakpoint::~Breakpoint()
{
}

bool
Breakpoint::IsInternal () const
{
    return LLDB_BREAK_ID_IS_INTERNAL(m_bid);
}


Target&
Breakpoint::GetTarget ()
{
    return m_target;
}

const Target&
Breakpoint::GetTarget () const
{
    return m_target;
}

BreakpointLocationSP
Breakpoint::AddLocation (const Address &addr, bool *new_location)
{
    return m_locations.AddLocation (addr, m_resolve_indirect_symbols, new_location);
}

BreakpointLocationSP
Breakpoint::FindLocationByAddress (const Address &addr)
{
    return m_locations.FindByAddress(addr);
}

break_id_t
Breakpoint::FindLocationIDByAddress (const Address &addr)
{
    return m_locations.FindIDByAddress(addr);
}

BreakpointLocationSP
Breakpoint::FindLocationByID (break_id_t bp_loc_id)
{
    return m_locations.FindByID(bp_loc_id);
}

BreakpointLocationSP
Breakpoint::GetLocationAtIndex (size_t index)
{
    return m_locations.GetByIndex(index);
}

void
Breakpoint::RemoveInvalidLocations (const ArchSpec &arch)
{
    m_locations.RemoveInvalidLocations(arch);
}

// For each of the overall options we need to decide how they propagate to
// the location options.  This will determine the precedence of options on
// the breakpoint vs. its locations.

// Disable at the breakpoint level should override the location settings.
// That way you can conveniently turn off a whole breakpoint without messing
// up the individual settings.

void
Breakpoint::SetEnabled (bool enable)
{
    if (enable == m_options.IsEnabled())
        return;

    m_options.SetEnabled(enable);
    if (enable)
        m_locations.ResolveAllBreakpointSites();
    else
        m_locations.ClearAllBreakpointSites();

    SendBreakpointChangedEvent (enable ? eBreakpointEventTypeEnabled : eBreakpointEventTypeDisabled);

}

bool
Breakpoint::IsEnabled ()
{
    return m_options.IsEnabled();
}

void
Breakpoint::SetIgnoreCount (uint32_t n)
{
    if (m_options.GetIgnoreCount() == n)
        return;

    m_options.SetIgnoreCount(n);
    SendBreakpointChangedEvent (eBreakpointEventTypeIgnoreChanged);
}

void
Breakpoint::DecrementIgnoreCount ()
{
    uint32_t ignore = m_options.GetIgnoreCount();
    if (ignore != 0)
        m_options.SetIgnoreCount(ignore - 1);
}

uint32_t
Breakpoint::GetIgnoreCount () const
{
    return m_options.GetIgnoreCount();
}

bool
Breakpoint::IgnoreCountShouldStop ()
{
    uint32_t ignore = GetIgnoreCount();
    if (ignore != 0)
    {
        // When we get here we know the location that caused the stop doesn't have an ignore count,
        // since by contract we call it first...  So we don't have to find & decrement it, we only have
        // to decrement our own ignore count.
        DecrementIgnoreCount();
        return false;
    }
    else
        return true;
}

uint32_t
Breakpoint::GetHitCount () const
{
    return m_locations.GetHitCount();
}

bool
Breakpoint::IsOneShot () const
{
    return m_options.IsOneShot();
}

void
Breakpoint::SetOneShot (bool one_shot)
{
    m_options.SetOneShot (one_shot);
}

void
Breakpoint::SetThreadID (lldb::tid_t thread_id)
{
    if (m_options.GetThreadSpec()->GetTID() == thread_id)
        return;

    m_options.GetThreadSpec()->SetTID(thread_id);
    SendBreakpointChangedEvent (eBreakpointEventTypeThreadChanged);
}

lldb::tid_t
Breakpoint::GetThreadID () const
{
    if (m_options.GetThreadSpecNoCreate() == NULL)
        return LLDB_INVALID_THREAD_ID;
    else
        return m_options.GetThreadSpecNoCreate()->GetTID();
}

void
Breakpoint::SetThreadIndex (uint32_t index)
{
    if (m_options.GetThreadSpec()->GetIndex() == index)
        return;

    m_options.GetThreadSpec()->SetIndex(index);
    SendBreakpointChangedEvent (eBreakpointEventTypeThreadChanged);
}

uint32_t
Breakpoint::GetThreadIndex() const
{
    if (m_options.GetThreadSpecNoCreate() == NULL)
        return 0;
    else
        return m_options.GetThreadSpecNoCreate()->GetIndex();
}

void
Breakpoint::SetThreadName (const char *thread_name)
{
    if (m_options.GetThreadSpec()->GetName() != NULL
        && ::strcmp (m_options.GetThreadSpec()->GetName(), thread_name) == 0)
        return;

    m_options.GetThreadSpec()->SetName (thread_name);
    SendBreakpointChangedEvent (eBreakpointEventTypeThreadChanged);
}

const char *
Breakpoint::GetThreadName () const
{
    if (m_options.GetThreadSpecNoCreate() == NULL)
        return NULL;
    else
        return m_options.GetThreadSpecNoCreate()->GetName();
}

void
Breakpoint::SetQueueName (const char *queue_name)
{
    if (m_options.GetThreadSpec()->GetQueueName() != NULL
        && ::strcmp (m_options.GetThreadSpec()->GetQueueName(), queue_name) == 0)
        return;

    m_options.GetThreadSpec()->SetQueueName (queue_name);
    SendBreakpointChangedEvent (eBreakpointEventTypeThreadChanged);
}

const char *
Breakpoint::GetQueueName () const
{
    if (m_options.GetThreadSpecNoCreate() == NULL)
        return NULL;
    else
        return m_options.GetThreadSpecNoCreate()->GetQueueName();
}

void
Breakpoint::SetCondition (const char *condition)
{
    m_options.SetCondition (condition);
    SendBreakpointChangedEvent (eBreakpointEventTypeConditionChanged);
}

const char *
Breakpoint::GetConditionText () const
{
    return m_options.GetConditionText();
}

// This function is used when "baton" doesn't need to be freed
void
Breakpoint::SetCallback (BreakpointHitCallback callback, void *baton, bool is_synchronous)
{
    // The default "Baton" class will keep a copy of "baton" and won't free
    // or delete it when it goes goes out of scope.
    m_options.SetCallback(callback, BatonSP (new Baton(baton)), is_synchronous);

    SendBreakpointChangedEvent (eBreakpointEventTypeCommandChanged);
}

// This function is used when a baton needs to be freed and therefore is
// contained in a "Baton" subclass.
void
Breakpoint::SetCallback (BreakpointHitCallback callback, const BatonSP &callback_baton_sp, bool is_synchronous)
{
    m_options.SetCallback(callback, callback_baton_sp, is_synchronous);
}

void
Breakpoint::ClearCallback ()
{
    m_options.ClearCallback ();
}

bool
Breakpoint::InvokeCallback (StoppointCallbackContext *context, break_id_t bp_loc_id)
{
    return m_options.InvokeCallback (context, GetID(), bp_loc_id);
}

BreakpointOptions *
Breakpoint::GetOptions ()
{
    return &m_options;
}

void
Breakpoint::ResolveBreakpoint ()
{
    if (m_resolver_sp)
        m_resolver_sp->ResolveBreakpoint(*m_filter_sp);
}

void
Breakpoint::ResolveBreakpointInModules (ModuleList &module_list, BreakpointLocationCollection &new_locations)
{
    m_locations.StartRecordingNewLocations(new_locations);

    m_resolver_sp->ResolveBreakpointInModules(*m_filter_sp, module_list);

    m_locations.StopRecordingNewLocations();
}

void
Breakpoint::ResolveBreakpointInModules (ModuleList &module_list, bool send_event)
{
    if (m_resolver_sp)
    {
        // If this is not an internal breakpoint, set up to record the new locations, then dispatch
        // an event with the new locations.
        if (!IsInternal() && send_event)
        {
            BreakpointEventData *new_locations_event = new BreakpointEventData (eBreakpointEventTypeLocationsAdded,
                                                                                shared_from_this());

            ResolveBreakpointInModules (module_list, new_locations_event->GetBreakpointLocationCollection());

            if (new_locations_event->GetBreakpointLocationCollection().GetSize() != 0)
            {
                SendBreakpointChangedEvent (new_locations_event);
            }
            else
                delete new_locations_event;
        }
        else
        {
            m_resolver_sp->ResolveBreakpointInModules(*m_filter_sp, module_list);
        }
    }
}

void
Breakpoint::ClearAllBreakpointSites ()
{
    m_locations.ClearAllBreakpointSites();
}

//----------------------------------------------------------------------
// ModulesChanged: Pass in a list of new modules, and
//----------------------------------------------------------------------

void
Breakpoint::ModulesChanged (ModuleList &module_list, bool load, bool delete_locations)
{
    Log *log (lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_BREAKPOINTS));
    if (log)
        log->Printf ("Breakpoint::ModulesChanged: num_modules: %zu load: %i delete_locations: %i\n",
                     module_list.GetSize(), load, delete_locations);

    Mutex::Locker modules_mutex(module_list.GetMutex());
    if (load)
    {
        // The logic for handling new modules is:
        // 1) If the filter rejects this module, then skip it.
        // 2) Run through the current location list and if there are any locations
        //    for that module, we mark the module as "seen" and we don't try to re-resolve
        //    breakpoint locations for that module.
        //    However, we do add breakpoint sites to these locations if needed.
        // 3) If we don't see this module in our breakpoint location list, call ResolveInModules.

        ModuleList new_modules;  // We'll stuff the "unseen" modules in this list, and then resolve
                                 // them after the locations pass.  Have to do it this way because
                                 // resolving breakpoints will add new locations potentially.

        for (ModuleSP module_sp : module_list.ModulesNoLocking())
        {
            bool seen = false;
            if (!m_filter_sp->ModulePasses (module_sp))
                continue;

            for (BreakpointLocationSP break_loc_sp : m_locations.BreakpointLocations())
            {
                if (!break_loc_sp->IsEnabled())
                    continue;
                SectionSP section_sp (break_loc_sp->GetAddress().GetSection());
                if (!section_sp || section_sp->GetModule() == module_sp)
                {
                    if (!seen)
                        seen = true;

                    if (!break_loc_sp->ResolveBreakpointSite())
                    {
                        if (log)
                            log->Printf ("Warning: could not set breakpoint site for breakpoint location %d of breakpoint %d.\n",
                                         break_loc_sp->GetID(), GetID());
                    }
                }
            }

            if (!seen)
                new_modules.AppendIfNeeded (module_sp);

        }

        if (new_modules.GetSize() > 0)
        {
            ResolveBreakpointInModules(new_modules);
        }
    }
    else
    {
        // Go through the currently set locations and if any have breakpoints in
        // the module list, then remove their breakpoint sites, and their locations if asked to.

        BreakpointEventData *removed_locations_event;
        if (!IsInternal())
            removed_locations_event = new BreakpointEventData (eBreakpointEventTypeLocationsRemoved,
                                                               shared_from_this());
        else
            removed_locations_event = NULL;

        size_t num_modules = module_list.GetSize();
        for (size_t i = 0; i < num_modules; i++)
        {
            ModuleSP module_sp (module_list.GetModuleAtIndexUnlocked (i));
            if (m_filter_sp->ModulePasses (module_sp))
            {
                size_t loc_idx = 0;
                size_t num_locations = m_locations.GetSize();
                BreakpointLocationCollection locations_to_remove;
                for (loc_idx = 0; loc_idx < num_locations; loc_idx++)
                {
                    BreakpointLocationSP break_loc_sp (m_locations.GetByIndex(loc_idx));
                    SectionSP section_sp (break_loc_sp->GetAddress().GetSection());
                    if (section_sp && section_sp->GetModule() == module_sp)
                    {
                        // Remove this breakpoint since the shared library is
                        // unloaded, but keep the breakpoint location around
                        // so we always get complete hit count and breakpoint
                        // lifetime info
                        break_loc_sp->ClearBreakpointSite();
                        if (removed_locations_event)
                        {
                            removed_locations_event->GetBreakpointLocationCollection().Add(break_loc_sp);
                        }
                        if (delete_locations)
                            locations_to_remove.Add (break_loc_sp);

                    }
                }

                if (delete_locations)
                {
                    size_t num_locations_to_remove = locations_to_remove.GetSize();
                    for (loc_idx = 0; loc_idx < num_locations_to_remove; loc_idx++)
                        m_locations.RemoveLocation  (locations_to_remove.GetByIndex(loc_idx));
                }
            }
        }
        SendBreakpointChangedEvent (removed_locations_event);
    }
}

namespace
{
static bool
SymbolContextsMightBeEquivalent(SymbolContext &old_sc, SymbolContext &new_sc)
{
    bool equivalent_scs = false;

    if (old_sc.module_sp.get() == new_sc.module_sp.get())
    {
        // If these come from the same module, we can directly compare the pointers:
        if (old_sc.comp_unit && new_sc.comp_unit
            && (old_sc.comp_unit == new_sc.comp_unit))
        {
            if (old_sc.function && new_sc.function
                && (old_sc.function == new_sc.function))
            {
                equivalent_scs = true;
            }
        }
        else if (old_sc.symbol && new_sc.symbol
                && (old_sc.symbol == new_sc.symbol))
        {
            equivalent_scs = true;
        }
    }
    else
    {
        // Otherwise we will compare by name...
        if (old_sc.comp_unit && new_sc.comp_unit)
        {
            if (FileSpec::Equal(*old_sc.comp_unit, *new_sc.comp_unit, true))
            {
                // Now check the functions:
                if (old_sc.function && new_sc.function
                    && (old_sc.function->GetName() == new_sc.function->GetName()))
                {
                    equivalent_scs = true;
                }
            }
        }
        else if (old_sc.symbol && new_sc.symbol)
        {
            if (Mangled::Compare(old_sc.symbol->GetMangled(), new_sc.symbol->GetMangled()) == 0)
            {
                equivalent_scs = true;
            }
        }
    }
    return equivalent_scs;
}
}

void
Breakpoint::ModuleReplaced (ModuleSP old_module_sp, ModuleSP new_module_sp)
{
    Log *log (lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_BREAKPOINTS));
    if (log)
        log->Printf ("Breakpoint::ModulesReplaced for %s\n",
                     old_module_sp->GetSpecificationDescription().c_str());
    // First find all the locations that are in the old module

    BreakpointLocationCollection old_break_locs;
    for (BreakpointLocationSP break_loc_sp : m_locations.BreakpointLocations())
    {
        SectionSP section_sp = break_loc_sp->GetAddress().GetSection();
        if (section_sp && section_sp->GetModule() == old_module_sp)
        {
            old_break_locs.Add(break_loc_sp);
        }
    }

    size_t num_old_locations = old_break_locs.GetSize();

    if (num_old_locations == 0)
    {
        // There were no locations in the old module, so we just need to check if there were any in the new module.
        ModuleList temp_list;
        temp_list.Append (new_module_sp);
        ResolveBreakpointInModules(temp_list);
    }
    else
    {
        // First search the new module for locations.
        // Then compare this with the old list, copy over locations that "look the same"
        // Then delete the old locations.
        // Finally remember to post the creation event.
        //
        // Two locations are the same if they have the same comp unit & function (by name) and there are the same number
        // of locations in the old function as in the new one.

        ModuleList temp_list;
        temp_list.Append (new_module_sp);
        BreakpointLocationCollection new_break_locs;
        ResolveBreakpointInModules(temp_list, new_break_locs);
        BreakpointLocationCollection locations_to_remove;
        BreakpointLocationCollection locations_to_announce;

        size_t num_new_locations = new_break_locs.GetSize();

        if (num_new_locations > 0)
        {
            // Break out the case of one location -> one location since that's the most common one, and there's no need
            // to build up the structures needed for the merge in that case.
            if (num_new_locations == 1 && num_old_locations == 1)
            {
                bool equivalent_locations = false;
                SymbolContext old_sc, new_sc;
                // The only way the old and new location can be equivalent is if they have the same amount of information:
                BreakpointLocationSP old_loc_sp = old_break_locs.GetByIndex(0);
                BreakpointLocationSP new_loc_sp = new_break_locs.GetByIndex(0);

                if (old_loc_sp->GetAddress().CalculateSymbolContext(&old_sc)
                    == new_loc_sp->GetAddress().CalculateSymbolContext(&new_sc))
                {
                    equivalent_locations = SymbolContextsMightBeEquivalent(old_sc, new_sc);
                }

                if (equivalent_locations)
                {
                    m_locations.SwapLocation (old_loc_sp, new_loc_sp);
                }
                else
                {
                    locations_to_remove.Add(old_loc_sp);
                    locations_to_announce.Add(new_loc_sp);
                }
            }
            else
            {
                //We don't want to have to keep computing the SymbolContexts for these addresses over and over,
                // so lets get them up front:

                typedef std::map<lldb::break_id_t, SymbolContext> IDToSCMap;
                IDToSCMap old_sc_map;
                for (size_t idx = 0; idx < num_old_locations; idx++)
                {
                    SymbolContext sc;
                    BreakpointLocationSP bp_loc_sp = old_break_locs.GetByIndex(idx);
                    lldb::break_id_t loc_id = bp_loc_sp->GetID();
                    bp_loc_sp->GetAddress().CalculateSymbolContext(&old_sc_map[loc_id]);
                }

                std::map<lldb::break_id_t, SymbolContext> new_sc_map;
                for (size_t idx = 0; idx < num_new_locations; idx++)
                {
                    SymbolContext sc;
                    BreakpointLocationSP bp_loc_sp = new_break_locs.GetByIndex(idx);
                    lldb::break_id_t loc_id = bp_loc_sp->GetID();
                    bp_loc_sp->GetAddress().CalculateSymbolContext(&new_sc_map[loc_id]);
                }
                // Take an element from the old Symbol Contexts
                while (old_sc_map.size() > 0)
                {
                    lldb::break_id_t old_id = old_sc_map.begin()->first;
                    SymbolContext &old_sc = old_sc_map.begin()->second;

                    // Count the number of entries equivalent to this SC for the old list:
                    std::vector<lldb::break_id_t> old_id_vec;
                    old_id_vec.push_back(old_id);

                    IDToSCMap::iterator tmp_iter;
                    for (tmp_iter = ++old_sc_map.begin(); tmp_iter != old_sc_map.end(); tmp_iter++)
                    {
                        if (SymbolContextsMightBeEquivalent (old_sc, tmp_iter->second))
                            old_id_vec.push_back (tmp_iter->first);
                    }

                    // Now find all the equivalent locations in the new list.
                    std::vector<lldb::break_id_t> new_id_vec;
                    for (tmp_iter = new_sc_map.begin(); tmp_iter != new_sc_map.end(); tmp_iter++)
                    {
                        if (SymbolContextsMightBeEquivalent (old_sc, tmp_iter->second))
                            new_id_vec.push_back(tmp_iter->first);
                    }

                    // Alright, if we have the same number of potentially equivalent locations in the old
                    // and new modules, we'll just map them one to one in ascending ID order (assuming the
                    // resolver's order would match the equivalent ones.
                    // Otherwise, we'll dump all the old ones, and just take the new ones, erasing the elements
                    // from both maps as we go.

                    if (old_id_vec.size() == new_id_vec.size())
                    {
                        sort(old_id_vec.begin(), old_id_vec.end());
                        sort(new_id_vec.begin(), new_id_vec.end());
                        size_t num_elements = old_id_vec.size();
                        for (size_t idx = 0; idx < num_elements; idx++)
                        {
                            BreakpointLocationSP old_loc_sp = old_break_locs.FindByIDPair(GetID(), old_id_vec[idx]);
                            BreakpointLocationSP new_loc_sp = new_break_locs.FindByIDPair(GetID(), new_id_vec[idx]);
                            m_locations.SwapLocation(old_loc_sp, new_loc_sp);
                            old_sc_map.erase(old_id_vec[idx]);
                            new_sc_map.erase(new_id_vec[idx]);
                        }
                    }
                    else
                    {
                        for (lldb::break_id_t old_id : old_id_vec)
                        {
                            locations_to_remove.Add(old_break_locs.FindByIDPair(GetID(), old_id));
                            old_sc_map.erase(old_id);
                        }
                        for (lldb::break_id_t new_id : new_id_vec)
                        {
                            locations_to_announce.Add(new_break_locs.FindByIDPair(GetID(), new_id));
                            new_sc_map.erase(new_id);
                        }
                    }
                }
            }
        }

        // Now remove the remaining old locations, and cons up a removed locations event.
        // Note, we don't put the new locations that were swapped with an old location on the locations_to_remove
        // list, so we don't need to worry about telling the world about removing a location we didn't tell them
        // about adding.

        BreakpointEventData *locations_event;
        if (!IsInternal())
            locations_event = new BreakpointEventData (eBreakpointEventTypeLocationsRemoved,
                                                               shared_from_this());
        else
            locations_event = NULL;

        for (BreakpointLocationSP loc_sp : locations_to_remove.BreakpointLocations())
        {
            m_locations.RemoveLocation(loc_sp);
            if (locations_event)
                locations_event->GetBreakpointLocationCollection().Add(loc_sp);
        }
        SendBreakpointChangedEvent (locations_event);

        // And announce the new ones.

        if (!IsInternal())
        {
            locations_event = new BreakpointEventData (eBreakpointEventTypeLocationsAdded,
                                                               shared_from_this());
            for (BreakpointLocationSP loc_sp : locations_to_announce.BreakpointLocations())
                    locations_event->GetBreakpointLocationCollection().Add(loc_sp);

            SendBreakpointChangedEvent (locations_event);
        }
        m_locations.Compact();
    }
}

void
Breakpoint::Dump (Stream *)
{
}

size_t
Breakpoint::GetNumResolvedLocations() const
{
    // Return the number of breakpoints that are actually resolved and set
    // down in the inferior process.
    return m_locations.GetNumResolvedLocations();
}

size_t
Breakpoint::GetNumLocations() const
{
    return m_locations.GetSize();
}

void
Breakpoint::GetDescription (Stream *s, lldb::DescriptionLevel level, bool show_locations)
{
    assert (s != NULL);

    if (!m_kind_description.empty())
    {
        if (level == eDescriptionLevelBrief)
        {
            s->PutCString (GetBreakpointKind());
            return;
        }
        else
            s->Printf("Kind: %s\n", GetBreakpointKind ());
    }

    const size_t num_locations = GetNumLocations ();
    const size_t num_resolved_locations = GetNumResolvedLocations ();

    // They just made the breakpoint, they don't need to be told HOW they made it...
    // Also, we'll print the breakpoint number differently depending on whether there is 1 or more locations.
    if (level != eDescriptionLevelInitial)
    {
        s->Printf("%i: ", GetID());
        GetResolverDescription (s);
        GetFilterDescription (s);
    }

    switch (level)
    {
    case lldb::eDescriptionLevelBrief:
    case lldb::eDescriptionLevelFull:
        if (num_locations > 0)
        {
            s->Printf(", locations = %" PRIu64, (uint64_t)num_locations);
            if (num_resolved_locations > 0)
                s->Printf(", resolved = %" PRIu64 ", hit count = %d", (uint64_t)num_resolved_locations, GetHitCount());
        }
        else
        {
            // Don't print the pending notification for exception resolvers since we don't generally
            // know how to set them until the target is run.
            if (m_resolver_sp->getResolverID() != BreakpointResolver::ExceptionResolver)
                s->Printf(", locations = 0 (pending)");
        }

        GetOptions()->GetDescription(s, level);

        if (level == lldb::eDescriptionLevelFull)
        {
            s->IndentLess();
            s->EOL();
        }
        break;

    case lldb::eDescriptionLevelInitial:
        s->Printf ("Breakpoint %i: ", GetID());
        if (num_locations == 0)
        {
            s->Printf ("no locations (pending).");
        }
        else if (num_locations == 1)
        {
            // If there is one location only, we'll just print that location information.  But don't do this if
            // show locations is true, then that will be handled below.
            if (show_locations == false)
            {
                GetLocationAtIndex(0)->GetDescription(s, level);
            }
            else
            {
                s->Printf ("%zd locations.", num_locations);
            }
        }
        else
        {
            s->Printf ("%zd locations.", num_locations);
        }
        s->EOL();
        break;
    case lldb::eDescriptionLevelVerbose:
        // Verbose mode does a debug dump of the breakpoint
        Dump (s);
        s->EOL ();
            //s->Indent();
        GetOptions()->GetDescription(s, level);
        break;

    default:
        break;
    }

    // The brief description is just the location name (1.2 or whatever).  That's pointless to
    // show in the breakpoint's description, so suppress it.
    if (show_locations && level != lldb::eDescriptionLevelBrief)
    {
        s->IndentMore();
        for (size_t i = 0; i < num_locations; ++i)
        {
            BreakpointLocation *loc = GetLocationAtIndex(i).get();
            loc->GetDescription(s, level);
            s->EOL();
        }
        s->IndentLess();
    }
}

void
Breakpoint::GetResolverDescription (Stream *s)
{
    if (m_resolver_sp)
        m_resolver_sp->GetDescription (s);
}


bool
Breakpoint::GetMatchingFileLine (const ConstString &filename, uint32_t line_number, BreakpointLocationCollection &loc_coll)
{
    // TODO: To be correct, this method needs to fill the breakpoint location collection
    //       with the location IDs which match the filename and line_number.
    //

    if (m_resolver_sp)
    {
        BreakpointResolverFileLine *resolverFileLine = dyn_cast<BreakpointResolverFileLine>(m_resolver_sp.get());
        if (resolverFileLine &&
            resolverFileLine->m_file_spec.GetFilename() == filename &&
            resolverFileLine->m_line_number == line_number)
        {
            return true;
        }
    }
    return false;
}

void
Breakpoint::GetFilterDescription (Stream *s)
{
    m_filter_sp->GetDescription (s);
}

void
Breakpoint::SendBreakpointChangedEvent (lldb::BreakpointEventType eventKind)
{
    if (!m_being_created
        && !IsInternal()
        && GetTarget().EventTypeHasListeners(Target::eBroadcastBitBreakpointChanged))
    {
        BreakpointEventData *data = new Breakpoint::BreakpointEventData (eventKind, shared_from_this());

        GetTarget().BroadcastEvent (Target::eBroadcastBitBreakpointChanged, data);
    }
}

void
Breakpoint::SendBreakpointChangedEvent (BreakpointEventData *data)
{

    if (data == NULL)
        return;

    if (!m_being_created
        && !IsInternal()
        && GetTarget().EventTypeHasListeners(Target::eBroadcastBitBreakpointChanged))
        GetTarget().BroadcastEvent (Target::eBroadcastBitBreakpointChanged, data);
    else
        delete data;
}

Breakpoint::BreakpointEventData::BreakpointEventData (BreakpointEventType sub_type,
                                                      const BreakpointSP &new_breakpoint_sp) :
    EventData (),
    m_breakpoint_event (sub_type),
    m_new_breakpoint_sp (new_breakpoint_sp)
{
}

Breakpoint::BreakpointEventData::~BreakpointEventData ()
{
}

const ConstString &
Breakpoint::BreakpointEventData::GetFlavorString ()
{
    static ConstString g_flavor ("Breakpoint::BreakpointEventData");
    return g_flavor;
}

const ConstString &
Breakpoint::BreakpointEventData::GetFlavor () const
{
    return BreakpointEventData::GetFlavorString ();
}


BreakpointSP &
Breakpoint::BreakpointEventData::GetBreakpoint ()
{
    return m_new_breakpoint_sp;
}

BreakpointEventType
Breakpoint::BreakpointEventData::GetBreakpointEventType () const
{
    return m_breakpoint_event;
}

void
Breakpoint::BreakpointEventData::Dump (Stream *s) const
{
}

const Breakpoint::BreakpointEventData *
Breakpoint::BreakpointEventData::GetEventDataFromEvent (const Event *event)
{
    if (event)
    {
        const EventData *event_data = event->GetData();
        if (event_data && event_data->GetFlavor() == BreakpointEventData::GetFlavorString())
            return static_cast <const BreakpointEventData *> (event->GetData());
    }
    return NULL;
}

BreakpointEventType
Breakpoint::BreakpointEventData::GetBreakpointEventTypeFromEvent (const EventSP &event_sp)
{
    const BreakpointEventData *data = GetEventDataFromEvent (event_sp.get());

    if (data == NULL)
        return eBreakpointEventTypeInvalidType;
    else
        return data->GetBreakpointEventType();
}

BreakpointSP
Breakpoint::BreakpointEventData::GetBreakpointFromEvent (const EventSP &event_sp)
{
    BreakpointSP bp_sp;

    const BreakpointEventData *data = GetEventDataFromEvent (event_sp.get());
    if (data)
        bp_sp = data->m_new_breakpoint_sp;

    return bp_sp;
}

size_t
Breakpoint::BreakpointEventData::GetNumBreakpointLocationsFromEvent (const EventSP &event_sp)
{
    const BreakpointEventData *data = GetEventDataFromEvent (event_sp.get());
    if (data)
        return data->m_locations.GetSize();

    return 0;
}

lldb::BreakpointLocationSP
Breakpoint::BreakpointEventData::GetBreakpointLocationAtIndexFromEvent (const lldb::EventSP &event_sp, uint32_t bp_loc_idx)
{
    lldb::BreakpointLocationSP bp_loc_sp;

    const BreakpointEventData *data = GetEventDataFromEvent (event_sp.get());
    if (data)
    {
        bp_loc_sp = data->m_locations.GetByIndex(bp_loc_idx);
    }

    return bp_loc_sp;
}