Breakpoint.cpp

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//===-- Breakpoint.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 "llvm/Support/Casting.h"
 
#include "lldb/Breakpoint/Breakpoint.h"
#include "lldb/Breakpoint/BreakpointLocation.h"
#include "lldb/Breakpoint/BreakpointLocationCollection.h"
#include "lldb/Breakpoint/BreakpointPrecondition.h"
#include "lldb/Breakpoint/BreakpointResolver.h"
#include "lldb/Breakpoint/BreakpointResolverFileLine.h"
#include "lldb/Core/Address.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ModuleList.h"
#include "lldb/Core/SearchFilter.h"
#include "lldb/Core/Section.h"
#include "lldb/Target/SectionLoadList.h"
#include "lldb/Symbol/CompileUnit.h"
#include "lldb/Symbol/Function.h"
#include "lldb/Symbol/Symbol.h"
#include "lldb/Symbol/SymbolContext.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/ThreadSpec.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/Stream.h"
#include "lldb/Utility/StreamString.h"
 
#include <memory>
 
using namespace lldb;
using namespace lldb_private;
using namespace llvm;
 
ConstString Breakpoint::GetEventIdentifier() {
  static ConstString g_identifier("event-identifier.breakpoint.changed");
  return g_identifier;
}
 
const char *Breakpoint::g_option_names[static_cast<uint32_t>(
    Breakpoint::OptionNames::LastOptionName)]{"Names", "Hardware"};
 
// 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(true),
      m_locations(*this), m_resolve_indirect_symbols(resolve_indirect_symbols),
      m_hit_counter() {
  m_being_created = false;
}
 
Breakpoint::Breakpoint(Target &new_target, const Breakpoint &source_bp)
    : m_being_created(true), m_hardware(source_bp.m_hardware),
      m_target(new_target), m_name_list(source_bp.m_name_list),
      m_options(source_bp.m_options), m_locations(*this),
      m_resolve_indirect_symbols(source_bp.m_resolve_indirect_symbols),
      m_hit_counter() {}
 
// Destructor
Breakpoint::~Breakpoint() = default;
 
BreakpointSP Breakpoint::CopyFromBreakpoint(TargetSP new_target,
    const Breakpoint& bp_to_copy_from) {
  if (!new_target)
    return BreakpointSP();
 
  BreakpointSP bp(new Breakpoint(*new_target, bp_to_copy_from));
  // Now go through and copy the filter & resolver:
  bp->m_resolver_sp = bp_to_copy_from.m_resolver_sp->CopyForBreakpoint(bp);
  bp->m_filter_sp = bp_to_copy_from.m_filter_sp->CreateCopy(new_target);
  return bp;
}
 
// Serialization
StructuredData::ObjectSP Breakpoint::SerializeToStructuredData() {
  // Serialize the resolver:
  StructuredData::DictionarySP breakpoint_dict_sp(
      new StructuredData::Dictionary());
  StructuredData::DictionarySP breakpoint_contents_sp(
      new StructuredData::Dictionary());
 
  if (!m_name_list.empty()) {
    StructuredData::ArraySP names_array_sp(new StructuredData::Array());
    for (auto name : m_name_list) {
      names_array_sp->AddItem(
          StructuredData::StringSP(new StructuredData::String(name)));
    }
    breakpoint_contents_sp->AddItem(Breakpoint::GetKey(OptionNames::Names),
                                    names_array_sp);
  }
 
  breakpoint_contents_sp->AddBooleanItem(
      Breakpoint::GetKey(OptionNames::Hardware), m_hardware);
 
  StructuredData::ObjectSP resolver_dict_sp(
      m_resolver_sp->SerializeToStructuredData());
  if (!resolver_dict_sp)
    return StructuredData::ObjectSP();
 
  breakpoint_contents_sp->AddItem(BreakpointResolver::GetSerializationKey(),
                                  resolver_dict_sp);
 
  StructuredData::ObjectSP filter_dict_sp(
      m_filter_sp->SerializeToStructuredData());
  if (!filter_dict_sp)
    return StructuredData::ObjectSP();
 
  breakpoint_contents_sp->AddItem(SearchFilter::GetSerializationKey(),
                                  filter_dict_sp);
 
  StructuredData::ObjectSP options_dict_sp(
      m_options.SerializeToStructuredData());
  if (!options_dict_sp)
    return StructuredData::ObjectSP();
 
  breakpoint_contents_sp->AddItem(BreakpointOptions::GetSerializationKey(),
                                  options_dict_sp);
 
  breakpoint_dict_sp->AddItem(GetSerializationKey(), breakpoint_contents_sp);
  return breakpoint_dict_sp;
}
 
lldb::BreakpointSP Breakpoint::CreateFromStructuredData(
    TargetSP target_sp, StructuredData::ObjectSP &object_data, Status &error) {
  BreakpointSP result_sp;
  if (!target_sp)
    return result_sp;
 
  StructuredData::Dictionary *breakpoint_dict = object_data->GetAsDictionary();
 
  if (!breakpoint_dict || !breakpoint_dict->IsValid()) {
    error.SetErrorString("Can't deserialize from an invalid data object.");
    return result_sp;
  }
 
  StructuredData::Dictionary *resolver_dict;
  bool success = breakpoint_dict->GetValueForKeyAsDictionary(
      BreakpointResolver::GetSerializationKey(), resolver_dict);
  if (!success) {
    error.SetErrorString("Breakpoint data missing toplevel resolver key");
    return result_sp;
  }
 
  Status create_error;
  BreakpointResolverSP resolver_sp =
      BreakpointResolver::CreateFromStructuredData(*resolver_dict,
                                                   create_error);
  if (create_error.Fail()) {
    error.SetErrorStringWithFormat(
        "Error creating breakpoint resolver from data: %s.",
        create_error.AsCString());
    return result_sp;
  }
 
  StructuredData::Dictionary *filter_dict;
  success = breakpoint_dict->GetValueForKeyAsDictionary(
      SearchFilter::GetSerializationKey(), filter_dict);
  SearchFilterSP filter_sp;
  if (!success)
    filter_sp =
        std::make_shared<SearchFilterForUnconstrainedSearches>(target_sp);
  else {
    filter_sp = SearchFilter::CreateFromStructuredData(target_sp, *filter_dict,
        create_error);
    if (create_error.Fail()) {
      error.SetErrorStringWithFormat(
          "Error creating breakpoint filter from data: %s.",
          create_error.AsCString());
      return result_sp;
    }
  }
 
  std::unique_ptr<BreakpointOptions> options_up;
  StructuredData::Dictionary *options_dict;
  Target& target = *target_sp;
  success = breakpoint_dict->GetValueForKeyAsDictionary(
      BreakpointOptions::GetSerializationKey(), options_dict);
  if (success) {
    options_up = BreakpointOptions::CreateFromStructuredData(
        target, *options_dict, create_error);
    if (create_error.Fail()) {
      error.SetErrorStringWithFormat(
          "Error creating breakpoint options from data: %s.",
          create_error.AsCString());
      return result_sp;
    }
  }
 
  bool hardware = false;
  success = breakpoint_dict->GetValueForKeyAsBoolean(
      Breakpoint::GetKey(OptionNames::Hardware), hardware);
 
  result_sp = target.CreateBreakpoint(filter_sp, resolver_sp, false,
                                      hardware, true);
 
  if (result_sp && options_up) {
    result_sp->m_options = *options_up;
  }
 
  StructuredData::Array *names_array;
  success = breakpoint_dict->GetValueForKeyAsArray(
      Breakpoint::GetKey(OptionNames::Names), names_array);
  if (success && names_array) {
    size_t num_names = names_array->GetSize();
    for (size_t i = 0; i < num_names; i++) {
      llvm::StringRef name;
      Status error;
      success = names_array->GetItemAtIndexAsString(i, name);
      target.AddNameToBreakpoint(result_sp, name.str().c_str(), error);
    }
  }
 
  return result_sp;
}
 
bool Breakpoint::SerializedBreakpointMatchesNames(
    StructuredData::ObjectSP &bkpt_object_sp, std::vector<std::string> &names) {
  if (!bkpt_object_sp)
    return false;
 
  StructuredData::Dictionary *bkpt_dict = bkpt_object_sp->GetAsDictionary();
  if (!bkpt_dict)
    return false;
 
  if (names.empty())
    return true;
 
  StructuredData::Array *names_array;
 
  bool success =
      bkpt_dict->GetValueForKeyAsArray(GetKey(OptionNames::Names), names_array);
  // If there are no names, it can't match these names;
  if (!success)
    return false;
 
  size_t num_names = names_array->GetSize();
 
  for (size_t i = 0; i < num_names; i++) {
    llvm::StringRef name;
    if (names_array->GetItemAtIndexAsString(i, name)) {
      if (llvm::is_contained(names, name))
        return true;
    }
  }
  return false;
}
 
const lldb::TargetSP Breakpoint::GetTargetSP() {
  return m_target.shared_from_this();
}
 
bool Breakpoint::IsInternal() const { return LLDB_BREAK_ID_IS_INTERNAL(m_bid); }
 
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();
}
 
uint32_t Breakpoint::GetHitCount() const { return m_hit_counter.GetValue(); }
 
bool Breakpoint::IsOneShot() const { return m_options.IsOneShot(); }
 
void Breakpoint::SetOneShot(bool one_shot) { m_options.SetOneShot(one_shot); }
 
bool Breakpoint::IsAutoContinue() const { return m_options.IsAutoContinue(); }
 
void Breakpoint::SetAutoContinue(bool auto_continue) {
  m_options.SetAutoContinue(auto_continue);
}
 
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() == nullptr)
    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() == nullptr)
    return 0;
  else
    return m_options.GetThreadSpecNoCreate()->GetIndex();
}
 
void Breakpoint::SetThreadName(const char *thread_name) {
  if (m_options.GetThreadSpec()->GetName() != nullptr &&
      ::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() == nullptr)
    return nullptr;
  else
    return m_options.GetThreadSpecNoCreate()->GetName();
}
 
void Breakpoint::SetQueueName(const char *queue_name) {
  if (m_options.GetThreadSpec()->GetQueueName() != nullptr &&
      ::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() == nullptr)
    return nullptr;
  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, std::make_shared<UntypedBaton>(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; }
 
const BreakpointOptions &Breakpoint::GetOptions() const { return m_options; }
 
void Breakpoint::ResolveBreakpoint() {
  if (m_resolver_sp) {
    ElapsedTime elapsed(m_resolve_time);
    m_resolver_sp->ResolveBreakpoint(*m_filter_sp);
  }
}
 
void Breakpoint::ResolveBreakpointInModules(
    ModuleList &module_list, BreakpointLocationCollection &new_locations) {
  ElapsedTime elapsed(m_resolve_time);
  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 {
      ElapsedTime elapsed(m_resolve_time);
      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));
  LLDB_LOGF(log,
            "Breakpoint::ModulesChanged: num_modules: %zu load: %i "
            "delete_locations: %i\n",
            module_list.GetSize(), load, delete_locations);
 
  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.Modules()) {
      bool seen = false;
      if (!m_filter_sp->ModulePasses(module_sp))
        continue;
 
      BreakpointLocationCollection locations_with_no_section;
      for (BreakpointLocationSP break_loc_sp :
           m_locations.BreakpointLocations()) {
 
        // If the section for this location was deleted, that means it's Module
        // has gone away but somebody forgot to tell us. Let's clean it up
        // here.
        Address section_addr(break_loc_sp->GetAddress());
        if (section_addr.SectionWasDeleted()) {
          locations_with_no_section.Add(break_loc_sp);
          continue;
        }
          
        if (!break_loc_sp->IsEnabled())
          continue;
        
        SectionSP section_sp(section_addr.GetSection());
        
        // If we don't have a Section, that means this location is a raw
        // address that we haven't resolved to a section yet.  So we'll have to
        // look in all the new modules to resolve this location. Otherwise, if
        // it was set in this module, re-resolve it here.
        if (section_sp && section_sp->GetModule() == module_sp) {
          if (!seen)
            seen = true;
 
          if (!break_loc_sp->ResolveBreakpointSite()) {
            LLDB_LOGF(log,
                      "Warning: could not set breakpoint site for "
                      "breakpoint location %d of breakpoint %d.\n",
                      break_loc_sp->GetID(), GetID());
          }
        }
      }
      
      size_t num_to_delete = locations_with_no_section.GetSize();
      
      for (size_t i = 0; i < num_to_delete; i++)
        m_locations.RemoveLocation(locations_with_no_section.GetByIndex(i));
 
      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 = nullptr;
 
    for (ModuleSP module_sp : module_list.Modules()) {
      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);
  }
}
 
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 (old_sc.comp_unit->GetPrimaryFile() ==
          new_sc.comp_unit->GetPrimaryFile()) {
        // 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));
  LLDB_LOGF(log, "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()) {
            llvm::sort(old_id_vec);
            llvm::sort(new_id_vec);
            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 = nullptr;
 
    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();
}
 
bool Breakpoint::HasResolvedLocations() const {
  return GetNumResolvedLocations() > 0;
}
 
size_t Breakpoint::GetNumLocations() const { return m_locations.GetSize(); }
 
bool Breakpoint::AddName(llvm::StringRef new_name) {
  m_name_list.insert(new_name.str().c_str());
  return true;
}
 
void Breakpoint::GetDescription(Stream *s, lldb::DescriptionLevel level,
                                bool show_locations) {
  assert(s != nullptr);
 
  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)");
    }
 
    m_options.GetDescription(s, level);
 
    if (m_precondition_sp)
      m_precondition_sp->GetDescription(*s, level);
 
    if (level == lldb::eDescriptionLevelFull) {
      if (!m_name_list.empty()) {
        s->EOL();
        s->Indent();
        s->Printf("Names:");
        s->EOL();
        s->IndentMore();
        for (std::string name : m_name_list) {
          s->Indent();
          s->Printf("%s\n", name.c_str());
        }
        s->IndentLess();
      }
      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 && !show_locations) {
      // There is only one location, so we'll just print that location
      // information.
      GetLocationAtIndex(0)->GetDescription(s, level);
    } else {
      s->Printf("%" PRIu64 " locations.", static_cast<uint64_t>(num_locations));
    }
    s->EOL();
    break;
 
  case lldb::eDescriptionLevelVerbose:
    // Verbose mode does a debug dump of the breakpoint
    Dump(s);
    s->EOL();
    // s->Indent();
    m_options.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(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());
 
    // TODO: Handle SourceLocationSpec column information
    if (resolverFileLine &&
        resolverFileLine->m_location_spec.GetFileSpec().GetFilename() ==
            filename &&
        resolverFileLine->m_location_spec.GetLine() == line_number) {
      return true;
    }
  }
  return false;
}
 
void Breakpoint::GetFilterDescription(Stream *s) {
  m_filter_sp->GetDescription(s);
}
 
bool Breakpoint::EvaluatePrecondition(StoppointCallbackContext &context) {
  if (!m_precondition_sp)
    return true;
 
  return m_precondition_sp->EvaluatePrecondition(context);
}
 
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 == nullptr)
    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() = default;
 
ConstString Breakpoint::BreakpointEventData::GetFlavorString() {
  static ConstString g_flavor("Breakpoint::BreakpointEventData");
  return g_flavor;
}
 
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 nullptr;
}
 
BreakpointEventType
Breakpoint::BreakpointEventData::GetBreakpointEventTypeFromEvent(
    const EventSP &event_sp) {
  const BreakpointEventData *data = GetEventDataFromEvent(event_sp.get());
 
  if (data == nullptr)
    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;
}
 
json::Value Breakpoint::GetStatistics() {
  json::Object bp;
  bp.try_emplace("id", GetID());
  bp.try_emplace("resolveTime", m_resolve_time.get().count());
  bp.try_emplace("numLocations", (int64_t)GetNumLocations());
  bp.try_emplace("numResolvedLocations", (int64_t)GetNumResolvedLocations());
  bp.try_emplace("internal", IsInternal());
  if (!m_kind_description.empty())
    bp.try_emplace("kindDescription", m_kind_description);
  // Put the full structured data for reproducing this breakpoint in a key/value
  // pair named "details". This allows the breakpoint's details to be visible
  // in the stats in case we need to reproduce a breakpoint that has long 
  // resolve times
  StructuredData::ObjectSP bp_data_sp = SerializeToStructuredData();
  if (bp_data_sp) {
    std::string buffer;
    llvm::raw_string_ostream ss(buffer);
    json::OStream json_os(ss);
    bp_data_sp->Serialize(json_os);
    if (auto expected_value = llvm::json::parse(ss.str())) {
      bp.try_emplace("details", std::move(*expected_value));
    } else {
      std::string details_error = toString(expected_value.takeError());
      json::Object details;
      details.try_emplace("error", details_error);
      bp.try_emplace("details", std::move(details));
    }
  }
  return json::Value(std::move(bp));
}