C++ ValueObjectSP::GetChildMemberWithName方法代码示例

CPPLanguageRuntime::LibCppStdFunctionCallableInfo
CPPLanguageRuntime::FindLibCppStdFunctionCallableInfo(
    lldb::ValueObjectSP &valobj_sp) {
  LibCppStdFunctionCallableInfo optional_info;

  if (!valobj_sp)
    return optional_info;

  // Member __f_ has type __base*, the contents of which will hold:
  // 1) a vtable entry which may hold type information needed to discover the
  //    lambda being called
  // 2) possibly hold a pointer to the callable object
  // e.g.
  //
  // (lldb) frame var -R  f_display
  // (std::__1::function<void (int)>) f_display = {
  //  __buf_ = {
  //  …
  // }
  //  __f_ = 0x00007ffeefbffa00
  // }
  // (lldb) memory read -fA 0x00007ffeefbffa00
  // 0x7ffeefbffa00: ... `vtable for std::__1::__function::__func<void (*) ...
  // 0x7ffeefbffa08: ... `print_num(int) at std_function_cppreference_exam ...
  //
  // We will be handling five cases below, std::function is wrapping:
  //
  // 1) a lambda we know at compile time. We will obtain the name of the lambda
  //    from the first template pameter from __func's vtable. We will look up
  //    the lambda's operator()() and obtain the line table entry.
  // 2) a lambda we know at runtime. A pointer to the lambdas __invoke method
  //    will be stored after the vtable. We will obtain the lambdas name from
  //    this entry and lookup operator()() and obtain the line table entry.
  // 3) a callable object via operator()(). We will obtain the name of the
  //    object from the first template parameter from __func's vtable. We will
  //    look up the objectc operator()() and obtain the line table entry.
  // 4) a member function. A pointer to the function will stored after the
  //    we will obtain the name from this pointer.
  // 5) a free function. A pointer to the function will stored after the vtable
  //    we will obtain the name from this pointer.
  ValueObjectSP member__f_(
      valobj_sp->GetChildMemberWithName(ConstString("__f_"), true));

  if (member__f_) {
    ValueObjectSP sub_member__f_(
       member__f_->GetChildMemberWithName(ConstString("__f_"), true));

    if (sub_member__f_)
        member__f_ = sub_member__f_;
  }

  lldb::addr_t member__f_pointer_value = member__f_->GetValueAsUnsigned(0);

  optional_info.member__f_pointer_value = member__f_pointer_value;

  ExecutionContext exe_ctx(valobj_sp->GetExecutionContextRef());
  Process *process = exe_ctx.GetProcessPtr();

  if (process == nullptr)
    return optional_info;

  uint32_t address_size = process->GetAddressByteSize();
  Status status;

  // First item pointed to by __f_ should be the pointer to the vtable for
  // a __base object.
  lldb::addr_t vtable_address =
      process->ReadPointerFromMemory(member__f_pointer_value, status);

  if (status.Fail())
    return optional_info;

  lldb::addr_t address_after_vtable = member__f_pointer_value + address_size;
  // As commened above we may not have a function pointer but if we do we will
  // need it.
  lldb::addr_t possible_function_address =
      process->ReadPointerFromMemory(address_after_vtable, status);

  if (status.Fail())
    return optional_info;

  Target &target = process->GetTarget();

  if (target.GetSectionLoadList().IsEmpty())
    return optional_info;

  Address vtable_addr_resolved;
  SymbolContext sc;
  Symbol *symbol;

  if (!target.GetSectionLoadList().ResolveLoadAddress(vtable_address,
                                                      vtable_addr_resolved))
    return optional_info;

  target.GetImages().ResolveSymbolContextForAddress(
      vtable_addr_resolved, eSymbolContextEverything, sc);
  symbol = sc.symbol;

  if (symbol == nullptr)
    return optional_info;
//.........这里部分代码省略.........