LanguageRuntime.cpp

//===-- LanguageRuntime.cpp -----------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "lldb/Target/LanguageRuntime.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/SearchFilter.h"
#include "lldb/Interpreter/CommandInterpreter.h"
#include "lldb/Target/Language.h"
#include "lldb/Target/Target.h"

using namespace lldb;
using namespace lldb_private;

char LanguageRuntime::ID = 0;

ExceptionSearchFilter::ExceptionSearchFilter(const lldb::TargetSP &target_sp,
                                             lldb::LanguageType language,
                                             bool update_module_list)
    : SearchFilter(target_sp, FilterTy::Exception), m_language(language),
      m_language_runtime(nullptr), m_filter_sp() {
  if (update_module_list)
    UpdateModuleListIfNeeded();
}

bool ExceptionSearchFilter::ModulePasses(const lldb::ModuleSP &module_sp) {
  UpdateModuleListIfNeeded();
  if (m_filter_sp)
    return m_filter_sp->ModulePasses(module_sp);
  return false;
}

bool ExceptionSearchFilter::ModulePasses(const FileSpec &spec) {
  UpdateModuleListIfNeeded();
  if (m_filter_sp)
    return m_filter_sp->ModulePasses(spec);
  return false;
}

void ExceptionSearchFilter::Search(Searcher &searcher) {
  UpdateModuleListIfNeeded();
  if (m_filter_sp)
    m_filter_sp->Search(searcher);
}

void ExceptionSearchFilter::GetDescription(Stream *s) {
  UpdateModuleListIfNeeded();
  if (m_filter_sp)
    m_filter_sp->GetDescription(s);
}

void ExceptionSearchFilter::UpdateModuleListIfNeeded() {
  ProcessSP process_sp(m_target_sp->GetProcessSP());
  if (process_sp) {
    bool refreash_filter = !m_filter_sp;
    if (m_language_runtime == nullptr) {
      m_language_runtime = process_sp->GetLanguageRuntime(m_language);
      refreash_filter = true;
    } else {
      LanguageRuntime *language_runtime =
          process_sp->GetLanguageRuntime(m_language);
      if (m_language_runtime != language_runtime) {
        m_language_runtime = language_runtime;
        refreash_filter = true;
      }
    }

    if (refreash_filter && m_language_runtime) {
      m_filter_sp = m_language_runtime->CreateExceptionSearchFilter();
    }
  } else {
    m_filter_sp.reset();
    m_language_runtime = nullptr;
  }
}

SearchFilterSP ExceptionSearchFilter::DoCreateCopy() {
  return SearchFilterSP(
      new ExceptionSearchFilter(TargetSP(), m_language, false));
}

SearchFilter *ExceptionSearchFilter::CreateFromStructuredData(
    Target &target, const StructuredData::Dictionary &data_dict,
    Status &error) {
  SearchFilter *result = nullptr;
  return result;
}

StructuredData::ObjectSP ExceptionSearchFilter::SerializeToStructuredData() {
  StructuredData::ObjectSP result_sp;

  return result_sp;
}

// The Target is the one that knows how to create breakpoints, so this function
// is meant to be used either by the target or internally in
// Set/ClearExceptionBreakpoints.
class ExceptionBreakpointResolver : public BreakpointResolver {
public:
  ExceptionBreakpointResolver(lldb::LanguageType language, bool catch_bp,
                              bool throw_bp)
      : BreakpointResolver(nullptr, BreakpointResolver::ExceptionResolver),
        m_language(language), m_catch_bp(catch_bp), m_throw_bp(throw_bp) {}

  ~ExceptionBreakpointResolver() override = default;

  Searcher::CallbackReturn SearchCallback(SearchFilter &filter,
                                          SymbolContext &context,
                                          Address *addr) override {

    if (SetActualResolver())
      return m_actual_resolver_sp->SearchCallback(filter, context, addr);
    else
      return eCallbackReturnStop;
  }

  lldb::SearchDepth GetDepth() override {
    if (SetActualResolver())
      return m_actual_resolver_sp->GetDepth();
    else
      return lldb::eSearchDepthTarget;
  }

  void GetDescription(Stream *s) override {
    Language *language_plugin = Language::FindPlugin(m_language);
    if (language_plugin)
      language_plugin->GetExceptionResolverDescription(m_catch_bp, m_throw_bp,
                                                       *s);
    else
      Language::GetDefaultExceptionResolverDescription(m_catch_bp, m_throw_bp,
                                                       *s);

    SetActualResolver();
    if (m_actual_resolver_sp) {
      s->Printf(" using: ");
      m_actual_resolver_sp->GetDescription(s);
    } else
      s->Printf(" the correct runtime exception handler will be determined "
                "when you run");
  }

  void Dump(Stream *s) const override {}

  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static inline bool classof(const BreakpointResolverName *) { return true; }
  static inline bool classof(const BreakpointResolver *V) {
    return V->getResolverID() == BreakpointResolver::ExceptionResolver;
  }

protected:
  BreakpointResolverSP CopyForBreakpoint(BreakpointSP &breakpoint) override {
    BreakpointResolverSP ret_sp(
        new ExceptionBreakpointResolver(m_language, m_catch_bp, m_throw_bp));
    ret_sp->SetBreakpoint(breakpoint);
    return ret_sp;
  }

  bool SetActualResolver() {
    BreakpointSP breakpoint_sp = GetBreakpoint();
    if (breakpoint_sp) {
      ProcessSP process_sp = breakpoint_sp->GetTarget().GetProcessSP();
      if (process_sp) {
        bool refreash_resolver = !m_actual_resolver_sp;
        if (m_language_runtime == nullptr) {
          m_language_runtime = process_sp->GetLanguageRuntime(m_language);
          refreash_resolver = true;
        } else {
          LanguageRuntime *language_runtime =
              process_sp->GetLanguageRuntime(m_language);
          if (m_language_runtime != language_runtime) {
            m_language_runtime = language_runtime;
            refreash_resolver = true;
          }
        }

        if (refreash_resolver && m_language_runtime) {
          m_actual_resolver_sp = m_language_runtime->CreateExceptionResolver(
              breakpoint_sp, m_catch_bp, m_throw_bp);
        }
      } else {
        m_actual_resolver_sp.reset();
        m_language_runtime = nullptr;
      }
    } else {
      m_actual_resolver_sp.reset();
      m_language_runtime = nullptr;
    }
    return (bool)m_actual_resolver_sp;
  }

  lldb::BreakpointResolverSP m_actual_resolver_sp;
  lldb::LanguageType m_language;
  LanguageRuntime *m_language_runtime = nullptr;
  bool m_catch_bp;
  bool m_throw_bp;
};

LanguageRuntime *LanguageRuntime::FindPlugin(Process *process,
                                             lldb::LanguageType language) {
  LanguageRuntimeCreateInstance create_callback;
  for (uint32_t idx = 0;
       (create_callback =
            PluginManager::GetLanguageRuntimeCreateCallbackAtIndex(idx)) !=
       nullptr;
       ++idx) {
    if (LanguageRuntime *runtime = create_callback(process, language))
      return runtime;
  }
  return nullptr;
}

LanguageRuntime::LanguageRuntime(Process *process) : Runtime(process) {}

BreakpointPreconditionSP
LanguageRuntime::GetExceptionPrecondition(LanguageType language,
                                          bool throw_bp) {
  LanguageRuntimeCreateInstance create_callback;
  for (uint32_t idx = 0;
       (create_callback =
            PluginManager::GetLanguageRuntimeCreateCallbackAtIndex(idx)) !=
       nullptr;
       idx++) {
    if (auto precondition_callback =
            PluginManager::GetLanguageRuntimeGetExceptionPreconditionAtIndex(
                idx)) {
      if (BreakpointPreconditionSP precond =
              precondition_callback(language, throw_bp))
        return precond;
    }
  }
  return BreakpointPreconditionSP();
}

BreakpointSP LanguageRuntime::CreateExceptionBreakpoint(
    Target &target, lldb::LanguageType language, bool catch_bp, bool throw_bp,
    bool is_internal) {
  BreakpointResolverSP resolver_sp(
      new ExceptionBreakpointResolver(language, catch_bp, throw_bp));
  SearchFilterSP filter_sp(
      new ExceptionSearchFilter(target.shared_from_this(), language));
  bool hardware = false;
  bool resolve_indirect_functions = false;
  BreakpointSP exc_breakpt_sp(
      target.CreateBreakpoint(filter_sp, resolver_sp, is_internal, hardware,
                              resolve_indirect_functions));
  if (exc_breakpt_sp) {
    if (auto precond = GetExceptionPrecondition(language, throw_bp))
      exc_breakpt_sp->SetPrecondition(precond);

    if (is_internal)
      exc_breakpt_sp->SetBreakpointKind("exception");
  }

  return exc_breakpt_sp;
}

UnwindPlanSP
LanguageRuntime::GetRuntimeUnwindPlan(Thread &thread, RegisterContext *regctx,
                                      bool &behaves_like_zeroth_frame) {
  ProcessSP process_sp = thread.GetProcess();
  if (!process_sp.get())
    return UnwindPlanSP();
  if (process_sp->GetDisableLangRuntimeUnwindPlans() == true)
    return UnwindPlanSP();
  for (const lldb::LanguageType lang_type : Language::GetSupportedLanguages()) {
    if (LanguageRuntime *runtime = process_sp->GetLanguageRuntime(lang_type)) {
      UnwindPlanSP plan_sp = runtime->GetRuntimeUnwindPlan(
          process_sp, regctx, behaves_like_zeroth_frame);
      if (plan_sp.get())
        return plan_sp;
    }
  }
  return UnwindPlanSP();
}

void LanguageRuntime::InitializeCommands(CommandObject *parent) {
  if (!parent)
    return;

  if (!parent->IsMultiwordObject())
    return;

  LanguageRuntimeCreateInstance create_callback;

  for (uint32_t idx = 0;
       (create_callback =
            PluginManager::GetLanguageRuntimeCreateCallbackAtIndex(idx)) !=
       nullptr;
       ++idx) {
    if (LanguageRuntimeGetCommandObject command_callback =
            PluginManager::GetLanguageRuntimeGetCommandObjectAtIndex(idx)) {
      CommandObjectSP command =
          command_callback(parent->GetCommandInterpreter());
      if (command) {
        // the CommandObject vended by a Language plugin cannot be created once
        // and cached because we may create multiple debuggers and need one
        // instance of the command each - the implementing function is meant to
        // create a new instance of the command each time it is invoked.
        parent->LoadSubCommand(command->GetCommandName().str().c_str(), command);
      }
    }
  }
}