%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1998-2018. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%%     http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
-module(erl_internal).

%% Define Erlang bifs, guard tests and other internal stuff.
%%
%% NOTE: All guard_bif(), arith_op(), bool_op() and comp_op() must be
%%       defined in bif.tab as 'ubif', i.e bif without trace wrapper.
%%       
%%       Why?
%%       
%%       Because the compiler uses an optimized instruction for
%%       the call to these bifs, which when loaded gets a direct 
%%       entry pointer inserted into itself by the loader, 
%%       instead of a bif table index as for regular bifs.
%%       
%%       If tracing is enabled on these bifs, when a module is loaded, 
%%       the direct entry pointer inserted into the call instruction 
%%       will be pointing to the trace wrapper, so even if tracing is 
%%       disabled for bifs, the loaded module will call these bifs through 
%%       the trace wrappers.
%%       
%%       The call instruction in question does not give enough information
%%       to call trace match function {caller} for it to succeed 
%%       other then by chance, and the 'return_to' trace flag works just
%%       as bad, so both will mostly say that the caller is 'undefined'. 
%%       Furthermore the calls to these bifs will still generate
%%       trace messages from the loaded module even if tracing is disabled 
%%       for them, and no one knows what else might be messed up.
%%
%%       That's why!
%%

-export([bif/2,bif/3,guard_bif/2,
	 type_test/2,new_type_test/2,old_type_test/2,old_bif/2]).
-export([arith_op/2,bool_op/2,comp_op/2,list_op/2,send_op/2,op_type/2]).

-export([is_type/2]).

-export([add_predefined_functions/1]).

%%---------------------------------------------------------------------------

%%  Erlang builtin functions allowed in guards.
-spec guard_bif(Name, Arity) -> boolean() when
      Name :: atom(),
      Arity :: arity().

%% Please keep the alphabetical order.
guard_bif(abs, 1) -> true;
guard_bif(binary_part, 2) -> true;
guard_bif(binary_part, 3) -> true;
guard_bif(bit_size, 1) -> true;
guard_bif(byte_size, 1) -> true;
guard_bif(ceil, 1) -> true;
guard_bif(element, 2) -> true;
guard_bif(float, 1) -> true;
guard_bif(floor, 1) -> true;
guard_bif(hd, 1) -> true;
guard_bif(is_map_key, 2) -> true;
guard_bif(length, 1) -> true;
guard_bif(map_size, 1) -> true;
guard_bif(map_get, 2) -> true;
guard_bif(node, 0) -> true;
guard_bif(node, 1) -> true;
guard_bif(round, 1) -> true;
guard_bif(self, 0) -> true;
guard_bif(size, 1) -> true;
guard_bif(tl, 1) -> true;
guard_bif(trunc, 1) -> true;
guard_bif(tuple_size, 1) -> true;
guard_bif(Name, A) -> new_type_test(Name, A).

%%  Erlang type tests.
-spec type_test(Name, Arity) -> boolean() when
      Name :: atom(),
      Arity :: arity().

type_test(Name, Arity) ->
    new_type_test(Name, Arity) orelse old_type_test(Name, Arity).

%%  Erlang new-style type tests.
-spec new_type_test(Name::atom(), Arity::arity()) -> boolean().

%% Please keep the alphabetical order.
new_type_test(is_atom, 1) -> true;
new_type_test(is_binary, 1) -> true;
new_type_test(is_bitstring, 1) -> true;
new_type_test(is_boolean, 1) -> true;
new_type_test(is_float, 1) -> true;
new_type_test(is_function, 1) -> true;
new_type_test(is_function, 2) -> true;
new_type_test(is_integer, 1) -> true;
new_type_test(is_list, 1) -> true;
new_type_test(is_map, 1) -> true;
new_type_test(is_number, 1) -> true;
new_type_test(is_pid, 1) -> true;
new_type_test(is_port, 1) -> true;
new_type_test(is_record, 2) -> true;
new_type_test(is_record, 3) -> true;
new_type_test(is_reference, 1) -> true;
new_type_test(is_tuple, 1) -> true;
new_type_test(Name, A) when is_atom(Name), is_integer(A) -> false.

%%  Erlang old-style type tests.
-spec old_type_test(Name::atom(), Arity::arity()) -> boolean().

old_type_test(integer, 1) -> true;
old_type_test(float, 1) -> true;
old_type_test(number, 1) -> true;
old_type_test(atom, 1) -> true;
old_type_test(list, 1) -> true;
old_type_test(tuple, 1) -> true;
old_type_test(pid, 1) -> true;
old_type_test(reference, 1) -> true;
old_type_test(port, 1) -> true;
old_type_test(binary, 1) -> true;
old_type_test(record, 2) -> true;
old_type_test(function, 1) -> true;
old_type_test(Name, A) when is_atom(Name), is_integer(A) -> false.

-spec arith_op(OpName, Arity) -> boolean() when
      OpName :: atom(),
      Arity :: arity().

arith_op('+', 1) -> true;
arith_op('-', 1) -> true;
arith_op('*', 2) -> true;
arith_op('/', 2) -> true;
arith_op('+', 2) -> true;
arith_op('-', 2) -> true;
arith_op('bnot', 1) -> true;
arith_op('div', 2) -> true;
arith_op('rem', 2) -> true;
arith_op('band', 2) -> true;
arith_op('bor', 2) -> true;
arith_op('bxor', 2) -> true;
arith_op('bsl', 2) -> true;
arith_op('bsr', 2) -> true;
arith_op(Op, A) when is_atom(Op), is_integer(A) -> false.

-spec bool_op(OpName, Arity) -> boolean() when
      OpName :: atom(),
      Arity :: arity().

bool_op('not', 1) -> true;
bool_op('and', 2) -> true;
bool_op('or', 2) -> true;
bool_op('xor', 2) -> true;
bool_op(Op, A) when is_atom(Op), is_integer(A) -> false.

-spec comp_op(OpName, Arity) -> boolean() when
      OpName :: atom(),
      Arity :: arity().

comp_op('==', 2) -> true;
comp_op('/=', 2) -> true;
comp_op('=<', 2) -> true;
comp_op('<', 2) -> true;
comp_op('>=', 2) -> true;
comp_op('>', 2) -> true;
comp_op('=:=', 2) -> true;
comp_op('=/=', 2) -> true;
comp_op(Op, A) when is_atom(Op), is_integer(A) -> false.

-spec list_op(OpName, Arity) -> boolean() when
      OpName :: atom(),
      Arity :: arity().

list_op('++', 2) -> true;
list_op('--', 2) -> true;
list_op(Op, A) when is_atom(Op), is_integer(A) -> false.

-spec send_op(OpName, Arity) -> boolean() when
      OpName :: atom(),
      Arity :: arity().

send_op('!', 2) -> true;
send_op(Op, A) when is_atom(Op), is_integer(A) -> false.

-spec op_type(OpName, Arity) -> Type when
      OpName :: atom(),
      Arity :: arity(),
      Type :: 'arith' | 'bool' | 'comp' | 'list' | 'send'.

op_type('+', 1) -> arith;
op_type('-', 1) -> arith;
op_type('*', 2) -> arith;
op_type('/', 2) -> arith;
op_type('+', 2) -> arith;
op_type('-', 2) -> arith;
op_type('bnot', 1) -> arith;
op_type('div', 2) -> arith;
op_type('rem', 2) -> arith;
op_type('band', 2) -> arith;
op_type('bor', 2) -> arith;
op_type('bxor', 2) -> arith;
op_type('bsl', 2) -> arith;
op_type('bsr', 2) -> arith;
op_type('not', 1) -> bool;
op_type('and', 2) -> bool;
op_type('or', 2) -> bool;
op_type('xor', 2) -> bool;
op_type('==', 2) -> comp;
op_type('/=', 2) -> comp;
op_type('=<', 2) -> comp;
op_type('<', 2) -> comp;
op_type('>=', 2) -> comp;
op_type('>', 2) -> comp;
op_type('=:=', 2) -> comp;
op_type('=/=', 2) -> comp;
op_type('++', 2) -> list;
op_type('--', 2) -> list;
op_type('!', 2) -> send.

-spec bif(Mod::atom(), Name::atom(), Arity::arity()) -> boolean().

bif(erlang, Name, Arity) -> bif(Name, Arity);
bif(M, F, A) when is_atom(M), is_atom(F), is_integer(A) -> false.

-spec bif(Name, Arity) -> boolean() when
      Name :: atom(),
      Arity::arity().
%%   Returns true if erlang:Name/Arity is an auto-imported BIF, false otherwise.
%%   Use erlang:is_bultin(Mod, Name, Arity) to find whether a function is a BIF
%%   (meaning implemented in C) or not.

bif(abs, 1) -> true;
bif(alias, 0) -> true;
bif(alias, 1) -> true;
bif(apply, 2) -> true;
bif(apply, 3) -> true;
bif(atom_to_binary, 1) -> true;
bif(atom_to_binary, 2) -> true;
bif(atom_to_list, 1) -> true;
bif(binary_part, 2) -> true;
bif(binary_part, 3) -> true;
bif(binary_to_atom, 1) -> true;
bif(binary_to_atom, 2) -> true;
bif(binary_to_existing_atom, 1) -> true;
bif(binary_to_existing_atom, 2) -> true;
bif(binary_to_integer, 1) -> true;
bif(binary_to_integer, 2) -> true;
bif(binary_to_float, 1) -> true;
bif(binary_to_list, 1) -> true;
bif(binary_to_list, 3) -> true;
bif(binary_to_term, 1) -> true;
bif(binary_to_term, 2) -> true;
bif(bitsize, 1) -> true;
bif(bit_size, 1) -> true;
bif(bitstring_to_list, 1) -> true;
bif(byte_size, 1) -> true;
bif(ceil, 1) -> true;
bif(check_old_code, 1) -> true;
bif(check_process_code, 2) -> true;
bif(check_process_code, 3) -> true;
bif(date, 0) -> true;
bif(delete_module, 1) -> true;
bif(demonitor, 1) -> true;
bif(demonitor, 2) -> true;
bif(disconnect_node, 1) -> true;
bif(element, 2) -> true;
bif(erase, 0) -> true;
bif(erase, 1) -> true;
bif(error, 1) -> true;
bif(error, 2) -> true;
bif(error, 3) -> true;
bif(exit, 1) -> true;
bif(exit, 2) -> true;
bif(float, 1) -> true;
bif(float_to_list, 1) -> true;
bif(float_to_list, 2) -> true;
bif(float_to_binary, 1) -> true;
bif(float_to_binary, 2) -> true;
bif(floor, 1) -> true;
bif(garbage_collect, 0) -> true;
bif(garbage_collect, 1) -> true;
bif(garbage_collect, 2) -> true;
bif(get, 0) -> true;
bif(get, 1) -> true;
bif(get_keys, 0) -> true;
bif(get_keys, 1) -> true;
bif(group_leader, 0) -> true;
bif(group_leader, 2) -> true;
bif(halt, 0) -> true;
bif(halt, 1) -> true;
bif(halt, 2) -> true;
bif(hd, 1) -> true;
bif(integer_to_binary, 1) -> true;
bif(integer_to_binary, 2) -> true;
bif(integer_to_list, 1) -> true;
bif(integer_to_list, 2) -> true;
bif(iolist_size, 1) -> true;
bif(iolist_to_binary, 1) -> true;
bif(is_alive, 0) -> true;
bif(is_process_alive, 1) -> true;
bif(is_atom, 1) -> true;
bif(is_boolean, 1) -> true;
bif(is_binary, 1) -> true;
bif(is_bitstring, 1) -> true;
bif(is_float, 1) -> true;
bif(is_function, 1) -> true;
bif(is_function, 2) -> true;
bif(is_integer, 1) -> true;
bif(is_list, 1) -> true;
bif(is_map, 1) -> true;
bif(is_map_key, 2) -> true;
bif(is_number, 1) -> true;
bif(is_pid, 1) -> true;
bif(is_port, 1) -> true;
bif(is_reference, 1) -> true;
bif(is_tuple, 1) -> true;
bif(is_record, 2) -> true;
bif(is_record, 3) -> true;
bif(length, 1) -> true;
bif(link, 1) -> true;
bif(list_to_atom, 1) -> true;
bif(list_to_binary, 1) -> true;
bif(list_to_bitstring, 1) -> true;
bif(list_to_existing_atom, 1) -> true;
bif(list_to_float, 1) -> true;
bif(list_to_integer, 1) -> true;
bif(list_to_integer, 2) -> true;
bif(list_to_pid, 1) -> true;
bif(list_to_port, 1) -> true;
bif(list_to_ref, 1) -> true;
bif(list_to_tuple, 1) -> true;
bif(load_module, 2) -> true;
bif(make_ref, 0) -> true;
bif(map_size,1) -> true;
bif(map_get,2) -> true;
bif(max,2) -> true;
bif(min,2) -> true;
bif(module_loaded, 1) -> true;
bif(monitor, 2) -> true;
bif(monitor, 3) -> true;
bif(monitor_node, 2) -> true;
bif(node, 0) -> true;
bif(node, 1) -> true;
bif(nodes, 0) -> true;
bif(nodes, 1) -> true;
bif(now, 0) -> true;
bif(open_port, 2) -> true;
bif(pid_to_list, 1) -> true;
bif(port_to_list, 1) -> true;
bif(port_close, 1) -> true;
bif(port_command, 2) -> true;
bif(port_command, 3) -> true;
bif(port_connect, 2) -> true;
bif(port_control, 3) -> true;
bif(pre_loaded, 0) -> true;
bif(process_flag, 2) -> true;
bif(process_flag, 3) -> true;
bif(process_info, 1) -> true;
bif(process_info, 2) -> true;
bif(processes, 0) -> true;
bif(purge_module, 1) -> true;
bif(put, 2) -> true;
bif(ref_to_list, 1) -> true;
bif(register, 2) -> true;
bif(registered, 0) -> true;
bif(round, 1) -> true;
bif(self, 0) -> true;
bif(setelement, 3) -> true;
bif(size, 1) -> true;
bif(spawn, 1) -> true;
bif(spawn, 2) -> true;
bif(spawn, 3) -> true;
bif(spawn, 4) -> true;
bif(spawn_link, 1) -> true;
bif(spawn_link, 2) -> true;
bif(spawn_link, 3) -> true;
bif(spawn_link, 4) -> true;
bif(spawn_request, 1) -> true;
bif(spawn_request, 2) -> true;
bif(spawn_request, 3) -> true;
bif(spawn_request, 4) -> true;
bif(spawn_request, 5) -> true;
bif(spawn_request_abandon, 1) -> true;
bif(spawn_monitor, 1) -> true;
bif(spawn_monitor, 2) -> true;
bif(spawn_monitor, 3) -> true;
bif(spawn_monitor, 4) -> true;
bif(spawn_opt, 2) -> true;
bif(spawn_opt, 3) -> true;
bif(spawn_opt, 4) -> true;
bif(spawn_opt, 5) -> true;
bif(split_binary, 2) -> true;
bif(statistics, 1) -> true;
bif(term_to_binary, 1) -> true;
bif(term_to_binary, 2) -> true;
bif(term_to_iovec, 1) -> true;
bif(term_to_iovec, 2) -> true;
bif(throw, 1) -> true;
bif(time, 0) -> true;
bif(tl, 1) -> true;
bif(trunc, 1) -> true;
bif(tuple_size, 1) -> true;
bif(tuple_to_list, 1) -> true;
bif(unalias, 1) -> true;
bif(unlink, 1) -> true;
bif(unregister, 1) -> true;
bif(whereis, 1) -> true;
bif(Name, A) when is_atom(Name), is_integer(A) -> false.

-spec old_bif(Name::atom(), Arity::arity()) -> boolean().
%%   Returns true if erlang:Name/Arity is an old (pre R14) auto-imported BIF, false otherwise.
%%   Use erlang:is_bultin(Mod, Name, Arity) to find whether a function is a BIF
%%   (meaning implemented in C) or not.

old_bif(abs, 1) -> true;
old_bif(apply, 2) -> true;
old_bif(apply, 3) -> true;
old_bif(atom_to_binary, 2) -> true;
old_bif(atom_to_list, 1) -> true;
old_bif(binary_to_atom, 2) -> true;
old_bif(binary_to_existing_atom, 2) -> true;
old_bif(binary_to_list, 1) -> true;
old_bif(binary_to_list, 3) -> true;
old_bif(binary_to_term, 1) -> true;
old_bif(bitsize, 1) -> true;
old_bif(bit_size, 1) -> true;
old_bif(bitstring_to_list, 1) -> true;
old_bif(byte_size, 1) -> true;
old_bif(check_process_code, 2) -> true;
old_bif(date, 0) -> true;
old_bif(delete_module, 1) -> true;
old_bif(disconnect_node, 1) -> true;
old_bif(element, 2) -> true;
old_bif(erase, 0) -> true;
old_bif(erase, 1) -> true;
old_bif(exit, 1) -> true;
old_bif(exit, 2) -> true;
old_bif(float, 1) -> true;
old_bif(float_to_list, 1) -> true;
old_bif(garbage_collect, 0) -> true;
old_bif(garbage_collect, 1) -> true;
old_bif(get, 0) -> true;
old_bif(get, 1) -> true;
old_bif(get_keys, 1) -> true;
old_bif(group_leader, 0) -> true;
old_bif(group_leader, 2) -> true;
old_bif(halt, 0) -> true;
old_bif(halt, 1) -> true;
old_bif(hd, 1) -> true;
old_bif(integer_to_list, 1) -> true;
old_bif(iolist_size, 1) -> true;
old_bif(iolist_to_binary, 1) -> true;
old_bif(is_alive, 0) -> true;
old_bif(is_process_alive, 1) -> true;
old_bif(is_atom, 1) -> true;
old_bif(is_boolean, 1) -> true;
old_bif(is_binary, 1) -> true;
old_bif(is_bitstring, 1) -> true;
old_bif(is_float, 1) -> true;
old_bif(is_function, 1) -> true;
old_bif(is_function, 2) -> true;
old_bif(is_integer, 1) -> true;
old_bif(is_list, 1) -> true;
old_bif(is_number, 1) -> true;
old_bif(is_pid, 1) -> true;
old_bif(is_port, 1) -> true;
old_bif(is_reference, 1) -> true;
old_bif(is_tuple, 1) -> true;
old_bif(is_record, 2) -> true;
old_bif(is_record, 3) -> true;
old_bif(length, 1) -> true;
old_bif(link, 1) -> true;
old_bif(list_to_atom, 1) -> true;
old_bif(list_to_binary, 1) -> true;
old_bif(list_to_bitstring, 1) -> true;
old_bif(list_to_existing_atom, 1) -> true;
old_bif(list_to_float, 1) -> true;
old_bif(list_to_integer, 1) -> true;
old_bif(list_to_pid, 1) -> true;
old_bif(list_to_tuple, 1) -> true;
old_bif(load_module, 2) -> true;
old_bif(make_ref, 0) -> true;
old_bif(module_loaded, 1) -> true;
old_bif(monitor_node, 2) -> true;
old_bif(node, 0) -> true;
old_bif(node, 1) -> true;
old_bif(nodes, 0) -> true;
old_bif(nodes, 1) -> true;
old_bif(now, 0) -> true;
old_bif(open_port, 2) -> true;
old_bif(pid_to_list, 1) -> true;
old_bif(port_close, 1) -> true;
old_bif(port_command, 2) -> true;
old_bif(port_connect, 2) -> true;
old_bif(port_control, 3) -> true;
old_bif(pre_loaded, 0) -> true;
old_bif(process_flag, 2) -> true;
old_bif(process_flag, 3) -> true;
old_bif(process_info, 1) -> true;
old_bif(process_info, 2) -> true;
old_bif(processes, 0) -> true;
old_bif(purge_module, 1) -> true;
old_bif(put, 2) -> true;
old_bif(register, 2) -> true;
old_bif(registered, 0) -> true;
old_bif(round, 1) -> true;
old_bif(self, 0) -> true;
old_bif(setelement, 3) -> true;
old_bif(size, 1) -> true;
old_bif(spawn, 1) -> true;
old_bif(spawn, 2) -> true;
old_bif(spawn, 3) -> true;
old_bif(spawn, 4) -> true;
old_bif(spawn_link, 1) -> true;
old_bif(spawn_link, 2) -> true;
old_bif(spawn_link, 3) -> true;
old_bif(spawn_link, 4) -> true;
old_bif(spawn_monitor, 1) -> true;
old_bif(spawn_monitor, 3) -> true;
old_bif(spawn_opt, 2) -> true;
old_bif(spawn_opt, 3) -> true;
old_bif(spawn_opt, 4) -> true;
old_bif(spawn_opt, 5) -> true;
old_bif(split_binary, 2) -> true;
old_bif(statistics, 1) -> true;
old_bif(term_to_binary, 1) -> true;
old_bif(term_to_binary, 2) -> true;
old_bif(throw, 1) -> true;
old_bif(time, 0) -> true;
old_bif(tl, 1) -> true;
old_bif(trunc, 1) -> true;
old_bif(tuple_size, 1) -> true;
old_bif(tuple_to_list, 1) -> true;
old_bif(unlink, 1) -> true;
old_bif(unregister, 1) -> true;
old_bif(whereis, 1) -> true;
old_bif(Name, A) when is_atom(Name), is_integer(A) -> false.

-spec is_type(Name, NumberOfTypeVariables) -> boolean() when
      Name :: atom(),
      NumberOfTypeVariables :: non_neg_integer().
%% Returns true if Name/NumberOfTypeVariables is a predefined type.

is_type(any, 0) -> true;
is_type(arity, 0) -> true;
is_type(atom, 0) -> true;
is_type(binary, 0) -> true;
is_type(bitstring, 0) -> true;
is_type(bool, 0) -> true;
is_type(boolean, 0) -> true;
is_type(byte, 0) -> true;
is_type(char, 0) -> true;
is_type(float, 0) -> true;
is_type(function, 0) -> true;
is_type(identifier, 0) -> true;
is_type(integer, 0) -> true;
is_type(iodata, 0) -> true;
is_type(iolist, 0) -> true;
is_type(list, 0) -> true;
is_type(list, 1) -> true;
is_type(map, 0) -> true;
is_type(maybe_improper_list, 0) -> true;
is_type(maybe_improper_list, 2) -> true;
is_type(mfa, 0) -> true;
is_type(module, 0) -> true;
is_type(neg_integer, 0) -> true;
is_type(nil, 0) -> true;
is_type(no_return, 0) -> true;
is_type(node, 0) -> true;
is_type(non_neg_integer, 0) -> true;
is_type(none, 0) -> true;
is_type(nonempty_improper_list, 2) -> true;
is_type(nonempty_list, 0) -> true;
is_type(nonempty_list, 1) -> true;
is_type(nonempty_maybe_improper_list, 0) -> true;
is_type(nonempty_maybe_improper_list, 2) -> true;
is_type(nonempty_string, 0) -> true;
is_type(number, 0) -> true;
is_type(pid, 0) -> true;
is_type(port, 0) -> true;
is_type(pos_integer, 0) -> true;
is_type(reference, 0) -> true;
is_type(string, 0) -> true;
is_type(term, 0) -> true;
is_type(timeout, 0) -> true;
is_type(tuple, 0) -> true;
is_type(_, _) -> false.

%%%
%%% Add and export the pre-defined functions:
%%%
%%%   module_info/0
%%%   module_info/1
%%%   behaviour_info/1 (optional)
%%%

-spec add_predefined_functions(Forms) -> UpdatedForms when
      Forms :: [erl_parse:abstract_form() | erl_parse:form_info()],
      UpdatedForms :: [erl_parse:abstract_form() | erl_parse:form_info()].

add_predefined_functions(Forms) ->
    Forms ++ predefined_functions(Forms).

predefined_functions(Forms) ->
    Attrs = [{Name,Val} || {attribute,_,Name,Val} <- Forms],
    {module,Mod} = lists:keyfind(module, 1, Attrs),
    Callbacks = [Callback || {callback,Callback} <- Attrs],
    OptionalCallbacks = get_optional_callbacks(Attrs),
    Mpf1 = module_predef_func_beh_info(Callbacks, OptionalCallbacks),
    Mpf2 = module_predef_funcs_mod_info(Mod),
    Mpf = [erl_parse:new_anno(F) || F <- Mpf1++Mpf2],
    Exp = [{F,A} || {function,_,F,A,_} <- Mpf],
    [{attribute,0,export,Exp}|Mpf].

get_optional_callbacks(Attrs) ->
    L = [O || {optional_callbacks,O} <- Attrs, is_fa_list(O)],
    lists:append(L).

is_fa_list([{FuncName, Arity}|L])
  when is_atom(FuncName), is_integer(Arity), Arity >= 0 ->
    is_fa_list(L);
is_fa_list([]) -> true;
is_fa_list(_) -> false.

module_predef_func_beh_info([], _) ->
    [];
module_predef_func_beh_info(Callbacks0, OptionalCallbacks) ->
    Callbacks = [FA || {{_,_}=FA,_} <- Callbacks0],
    List = make_list(Callbacks),
    OptionalList = make_list(OptionalCallbacks),
    [{function,0,behaviour_info,1,
      [{clause,0,[{atom,0,callbacks}],[],[List]},
       {clause,0,[{atom,0,optional_callbacks}],[],[OptionalList]}]}].

make_list([]) -> {nil,0};
make_list([{Name,Arity}|Rest]) ->
    {cons,0,
     {tuple,0,
      [{atom,0,Name},
       {integer,0,Arity}]},
     make_list(Rest)}.

module_predef_funcs_mod_info(Mod) ->
    ModAtom = {atom,0,Mod},
    [{function,0,module_info,0,
      [{clause,0,[],[],
        [{call,0,{remote,0,{atom,0,erlang},{atom,0,get_module_info}},
          [ModAtom]}]}]},
     {function,0,module_info,1,
      [{clause,0,[{var,0,'X'}],[],
        [{call,0,{remote,0,{atom,0,erlang},{atom,0,get_module_info}},
          [ModAtom,{var,0,'X'}]}]}]}].
