%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2000-2010. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
-module(xref_reader).
-export([module/5]).
-import(lists, [keysearch/3, member/2, reverse/1]).
-record(xrefr,
{module=[],
function=[],
def_at=[],
l_call_at=[],
x_call_at=[],
el=[],
ex=[],
x=[],
df,
builtins_too=false,
is_abstr, % abstract module?
funvars=[], % records variables bound to funs
% (for coping with list comprehension)
matches=[], % records other bound variables
unresolved=[], % unresolved calls, {{mfa(),mfa()},Line}
%% experimental; -xref(FunEdge) is recognized.
lattrs=[], % local calls, {{mfa(),mfa()},Line}
xattrs=[], % external calls, -"-
battrs=[] % badly formed xref attributes, term().
}).
-include("xref.hrl").
%% sys_pre_expand has modified the forms slightly compared to what
%% erl_id_trans recognizes.
%% The versions of the abstract code are as follows:
%% R7: abstract_v1
%% R8: abstract_v2
%% -> {ok, Module, {DefAt, CallAt, LC, XC, X, Attrs}, Unresolved}} | EXIT
%% Attrs = {ALC, AXC, Bad}
%% ALC, AXC and Bad are extracted from the attribute 'xref'. An experiment.
module(Module, Forms, CollectBuiltins, X, DF) ->
Attrs = [{Attr,V} || {attribute,_Line,Attr,V} <- Forms],
IsAbstract = xref_utils:is_abstract_module(Attrs),
S = #xrefr{module = Module, builtins_too = CollectBuiltins,
is_abstr = IsAbstract, x = X, df = DF},
forms(Forms, S).
forms([F | Fs], S) ->
S1 = form(F, S),
forms(Fs, S1);
forms([], S) ->
#xrefr{module = M, def_at = DefAt,
l_call_at = LCallAt, x_call_at = XCallAt,
el = LC, ex = XC, x = X, df = Depr,
lattrs = AL, xattrs = AX, battrs = B, unresolved = U} = S,
Attrs = {lists:reverse(AL), lists:reverse(AX), lists:reverse(B)},
{ok, M, {DefAt, LCallAt, XCallAt, LC, XC, X, Attrs, Depr}, U}.
form({attribute, Line, xref, Calls}, S) -> % experimental
#xrefr{module = M, function = Fun,
lattrs = L, xattrs = X, battrs = B} = S,
attr(Calls, Line, M, Fun, L, X, B, S);
form({attribute, _Line, _Attr, _Val}, S) ->
S;
form({function, 0, module_info, 0, _Clauses}, S) ->
S;
form({function, 0, module_info, 1, _Clauses}, S) ->
S;
form({function, Line, Name, Arity, Clauses}, S) ->
MFA0 = {S#xrefr.module, Name, Arity},
MFA = adjust_arity(S, MFA0),
S1 = S#xrefr{function = MFA},
S2 = S1#xrefr{def_at = [{MFA,Line} | S#xrefr.def_at]},
S3 = clauses(Clauses, S2),
S3#xrefr{function = []}.
clauses(Cls, S) ->
#xrefr{funvars = FunVars, matches = Matches} = S,
clauses(Cls, FunVars, Matches, S).
clauses([{clause, _Line, _H, G, B} | Cs], FunVars, Matches, S) ->
S1 = case S#xrefr.builtins_too of
true -> expr(G, S);
false -> S
end,
S2 = expr(B, S1),
S3 = S2#xrefr{funvars = FunVars, matches = Matches},
clauses(Cs, S3);
clauses([], _FunVars, _Matches, S) ->
S.
attr([E={From, To} | As], Ln, M, Fun, AL, AX, B, S) ->
case mfa(From, M) of
{_, _, MFA} when MFA =:= Fun; [] =:= Fun ->
attr(From, To, Ln, M, Fun, AL, AX, B, S, As, E);
{_, _, _} ->
attr(As, Ln, M, Fun, AL, AX, [E | B], S);
_ ->
attr(Fun, E, Ln, M, Fun, AL, AX, B, S, As, E)
end;
attr([To | As], Ln, M, Fun, AL, AX, B, S) ->
attr(Fun, To, Ln, M, Fun, AL, AX, B, S, As, To);
attr([], _Ln, _M, _Fun, AL, AX, B, S) ->
S#xrefr{lattrs = AL, xattrs = AX, battrs = B}.
attr(From, To, Ln, M, Fun, AL, AX, B, S, As, E) ->
case {mfa(From, M), mfa(To, M)} of
{{true,_,F}, {_,external,T}} ->
attr(As, Ln, M, Fun, AL, [{{F,T},Ln} | AX], B, S);
{{true,_,F}, {_,local,T}} ->
attr(As, Ln, M, Fun, [{{F,T},Ln} | AL], AX, B, S);
_ -> attr(As, Ln, M, Fun, AL, AX, [E | B], S)
end.
mfa({F,A}, M) when is_atom(F), is_integer(A) ->
{true, local, {M,F,A}};
mfa(MFA={M,F,A}, M1) when is_atom(M), is_atom(F), is_integer(A) ->
{M=:=M1, external, MFA};
mfa(_, _M) -> false.
expr({'if', _Line, Cs}, S) ->
clauses(Cs, S);
expr({'case', _Line, E, Cs}, S) ->
S1 = expr(E, S),
clauses(Cs, S1);
expr({'receive', _Line, Cs}, S) ->
clauses(Cs, S);
expr({'receive', _Line, Cs, To, ToEs}, S) ->
S1 = expr(To, S),
S2 = expr(ToEs, S1),
clauses(Cs, S2);
expr({'try',_Line,Es,Scs,Ccs,As}, S) ->
S1 = expr(Es, S),
S2 = clauses(Scs, S1),
S3 = clauses(Ccs, S2),
expr(As, S3);
expr({'fun', Line, {function, {atom,_,Mod},
{atom,_,Name},
{integer,_,Arity}}}, S) ->
%% New format in R15. M:F/A (literals).
As = lists:duplicate(Arity, {atom, Line, foo}),
external_call(Mod, Name, As, Line, false, S);
expr({'fun', Line, {function, Mod, Name, {integer,_,Arity}}}, S) ->
%% New format in R15. M:F/A (one or more variables).
As = lists:duplicate(Arity, {atom, Line, foo}),
external_call(erlang, apply, [Mod, Name, list2term(As)], Line, true, S);
expr({'fun', Line, {function, Mod, Name, _Arity}}, S) ->
%% New format in R15. M:F/A (one or more variables).
As = {var, Line, '_'},
external_call(erlang, apply, [Mod, Name, As], Line, true, S);
expr({'fun', Line, {function, Name, Arity}, _Extra}, S) ->
%% Added in R8.
handle_call(local, S#xrefr.module, Name, Arity, Line, S);
expr({'fun', _Line, {clauses, Cs}, _Extra}, S) ->
clauses(Cs, S);
expr({call, Line, {atom, _, Name}, As}, S) ->
S1 = handle_call(local, S#xrefr.module, Name, length(As), Line, S),
expr(As, S1);
expr({call, Line, {remote, _Line, {atom,_,Mod}, {atom,_,Name}}, As}, S) ->
external_call(Mod, Name, As, Line, false, S);
expr({call, Line, {remote, _Line, Mod, Name}, As}, S) ->
%% Added in R8.
external_call(erlang, apply, [Mod, Name, list2term(As)], Line, true, S);
expr({call, Line, F, As}, S) ->
external_call(erlang, apply, [F, list2term(As)], Line, true, S);
expr({match, _Line, {var,_,Var}, {'fun', _, {clauses, Cs}, _Extra}}, S) ->
%% This is what is needed in R7 to avoid warnings for the functions
%% that are passed around by the "expansion" of list comprehension.
S1 = S#xrefr{funvars = [Var | S#xrefr.funvars]},
clauses(Cs, S1);
expr({match, _Line, {var,_,Var}, E}, S) ->
%% Used for resolving code like
%% Args = [A,B], apply(m, f, Args)
S1 = S#xrefr{matches = [{Var, E} | S#xrefr.matches]},
expr(E, S1);
expr({op, _Line, 'orelse', Op1, Op2}, S) ->
expr([Op1, Op2], S);
expr({op, _Line, 'andalso', Op1, Op2}, S) ->
expr([Op1, Op2], S);
expr({op, Line, Op, Operand1, Operand2}, S) ->
external_call(erlang, Op, [Operand1, Operand2], Line, false, S);
expr({op, Line, Op, Operand}, S) ->
external_call(erlang, Op, [Operand], Line, false, S);
expr(T, S) when is_tuple(T) ->
expr(tuple_to_list(T), S);
expr([E | Es], S) ->
expr(Es, expr(E, S));
expr(_E, S) ->
S.
%% Mod and Fun may not correspond to something in the abstract code,
%% which is signalled by X =:= true.
external_call(Mod, Fun, ArgsList, Line, X, S) ->
Arity = length(ArgsList),
W = case xref_utils:is_funfun(Mod, Fun, Arity) of
true when erlang =:= Mod, apply =:= Fun, 2 =:= Arity -> apply2;
true when erts_debug =:= Mod, apply =:= Fun,4 =:= Arity -> debug4;
true when erlang =:= Mod, spawn_opt =:= Fun -> Arity - 1;
true -> Arity;
false when Mod =:= erlang ->
case erl_internal:type_test(Fun, Arity) of
true -> type;
false -> false
end;
false -> false
end,
S1 = if
W =:= type; X ->
S;
true ->
handle_call(external, Mod, Fun, Arity, Line, S)
end,
case {W, ArgsList} of
{false, _} ->
expr(ArgsList, S1);
{type, _} ->
expr(ArgsList, S1);
{apply2, [{tuple, _, [M,F]}, ArgsTerm]} ->
eval_args(M, F, ArgsTerm, Line, S1, ArgsList, []);
{1, [{tuple, _, [M,F]} | R]} -> % R = [] unless spawn_opt
eval_args(M, F, list2term([]), Line, S1, ArgsList, R);
{2, [Node, {tuple, _, [M,F]} | R]} -> % R = [] unless spawn_opt
eval_args(M, F, list2term([]), Line, S1, ArgsList, [Node | R]);
{3, [M, F, ArgsTerm | R]} -> % R = [] unless spawn_opt
eval_args(M, F, ArgsTerm, Line, S1, ArgsList, R);
{4, [Node, M, F, ArgsTerm | R]} -> % R = [] unless spawn_opt
eval_args(M, F, ArgsTerm, Line, S1, ArgsList, [Node | R]);
{debug4, [M, F, ArgsTerm, _]} ->
eval_args(M, F, ArgsTerm, Line, S1, ArgsList, []);
_Else -> % apply2, 1 or 2
check_funarg(W, ArgsList, Line, S1)
end.
eval_args(Mod, Fun, ArgsTerm, Line, S, ArgsList, Extra) ->
{IsSimpleCall, M, F} = mod_fun(Mod, Fun),
case term2list(ArgsTerm, [], S) of
undefined ->
S1 = unresolved(M, F, -1, Line, S),
expr(ArgsList, S1);
ArgsList2 when not IsSimpleCall ->
S1 = unresolved(M, F, length(ArgsList2), Line, S),
expr(ArgsList, S1);
ArgsList2 when IsSimpleCall ->
S1 = expr(Extra, S),
external_call(M, F, ArgsList2, Line, false, S1)
end.
mod_fun({atom,_,M1}, {atom,_,F1}) -> {true, M1, F1};
mod_fun({atom,_,M1}, _) -> {false, M1, ?VAR_EXPR};
mod_fun(_, {atom,_,F1}) -> {false, ?MOD_EXPR, F1};
mod_fun(_, _) -> {false, ?MOD_EXPR, ?VAR_EXPR}.
check_funarg(W, ArgsList, Line, S) ->
{FunArg, Args} = fun_args(W, ArgsList),
S1 = case funarg(FunArg, S) of
true ->
S;
false when is_integer(W) -> % 1 or 2
unresolved(?MOD_EXPR, ?VAR_EXPR, 0, Line, S);
false -> % apply2
N = case term2list(Args, [], S) of
undefined -> -1;
As -> length(As)
end,
unresolved(?MOD_EXPR, ?VAR_EXPR, N, Line, S)
end,
expr(ArgsList, S1).
funarg({'fun', _, _Clauses, _Extra}, _S) -> true;
funarg({'fun', _, {function,_,_,_}}, _S) ->
%% New abstract format for fun M:F/A in R15.
true;
funarg({var, _, Var}, S) -> member(Var, S#xrefr.funvars);
funarg(_, _S) -> false.
fun_args(apply2, [FunArg, Args]) -> {FunArg, Args};
fun_args(1, [FunArg | Args]) -> {FunArg, Args};
fun_args(2, [_Node, FunArg | Args]) -> {FunArg, Args}.
list2term([A | As]) ->
{cons, 0, A, list2term(As)};
list2term([]) ->
{nil, 0}.
term2list({cons, _Line, H, T}, L, S) ->
term2list(T, [H | L], S);
term2list({nil, _Line}, L, _S) ->
reverse(L);
term2list({var, _, Var}, L, S) ->
case keysearch(Var, 1, S#xrefr.matches) of
{value, {Var, E}} ->
term2list(E, L, S);
false ->
undefined
end;
term2list(_Else, _L, _S) ->
undefined.
unresolved(M, F, A, Line, S) ->
handle_call(external, {M,F,A}, Line, S, true).
handle_call(Locality, Module, Name, Arity, Line, S) ->
case xref_utils:is_builtin(Module, Name, Arity) of
true when not S#xrefr.builtins_too -> S;
_Else ->
To = {Module, Name, Arity},
handle_call(Locality, To, Line, S, false)
end.
handle_call(Locality, To0, Line, S, IsUnres) ->
From = S#xrefr.function,
To = adjust_arity(S, To0),
Call = {From, To},
CallAt = {Call, Line},
S1 = if
IsUnres ->
S#xrefr{unresolved = [CallAt | S#xrefr.unresolved]};
true ->
S
end,
case Locality of
local ->
S1#xrefr{el = [Call | S1#xrefr.el],
l_call_at = [CallAt | S1#xrefr.l_call_at]};
external ->
S1#xrefr{ex = [Call | S1#xrefr.ex],
x_call_at = [CallAt | S1#xrefr.x_call_at]}
end.
adjust_arity(#xrefr{is_abstr = true, module = M}, {M, F, A} = MFA) ->
case xref_utils:is_static_function(F, A) of
true ->
MFA;
false ->
{M,F,A-1}
end;
adjust_arity(_S, MFA) ->
MFA.
