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authorBjörn Gustavsson <[email protected]>2016-08-15 15:34:06 +0200
committerBjörn Gustavsson <[email protected]>2016-09-02 14:24:36 +0200
commit0baa07cdf2754748bbc2d969bf83f08c0976fb78 (patch)
treeb5d649dbe4778d8488ae09a99e68435adc216342 /lib/stdlib/src
parent8a04dd4dd2d479efe488b0bed118e10559835fb6 (diff)
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Fix overridden BIFs
The filters in a list comprehension can be guard expressions or an ordinary expressions. If a guard expression is used as a filter, an exception will basically mean the same as 'false': t() -> L = [{some_tag,42},an_atom], [X || X <- L, element(1, X) =:= some_tag] %% Returns [{some_tag,42}] On the other hand, if an ordinary expression is used as a filter, there will be an exception: my_element(N, T) -> element(N, T). t() -> L = [{some_tag,42},an_atom], [X || X <- L, my_element(1, X) =:= some_tag] %% Causes a 'badarg' exception when element(1, an_atom) is evaluated It has been allowed for several releases to override a BIF with a local function. Thus, if we define a function called element/2, it will be called instead of the BIF element/2 within the module. We must use the "erlang:" prefix to call the BIF. Therefore, the following code is expected to work the same way as in our second example above: -compile({no_auto_import,[element/2]}). element(N, T) -> erlang:element(N, T). t() -> L = [{some_tag,42},an_atom], [X || X <- L, element(1, X) =:= some_tag]. %% Causes a 'badarg' exception when element(1, an_atom) is evaluated But the compiler refuses to compile the code with the following diagnostic: call to local/imported function element/2 is illegal in guard
Diffstat (limited to 'lib/stdlib/src')
-rw-r--r--lib/stdlib/src/erl_expand_records.erl11
-rw-r--r--lib/stdlib/src/erl_lint.erl137
-rw-r--r--lib/stdlib/src/qlc_pt.erl46
3 files changed, 129 insertions, 65 deletions
diff --git a/lib/stdlib/src/erl_expand_records.erl b/lib/stdlib/src/erl_expand_records.erl
index ab47f05320..2280464bff 100644
--- a/lib/stdlib/src/erl_expand_records.erl
+++ b/lib/stdlib/src/erl_expand_records.erl
@@ -507,9 +507,16 @@ lc_tq(Line, [{b_generate,Lg,P0,G0} | Qs0], St0) ->
{P1,St2} = pattern(P0, St1),
{Qs1,St3} = lc_tq(Line, Qs0, St2),
{[{b_generate,Lg,P1,G1} | Qs1],St3};
-lc_tq(Line, [F0 | Qs0], St0) ->
+lc_tq(Line, [F0 | Qs0], #exprec{calltype=Calltype}=St0) ->
%% Allow record/2 and expand out as guard test.
- case erl_lint:is_guard_test(F0) of
+ IsOverriden = fun(FA) ->
+ case Calltype of
+ #{FA := local} -> true;
+ #{FA := {imported,_}} -> true;
+ _ -> false
+ end
+ end,
+ case erl_lint:is_guard_test(F0, [], IsOverriden) of
true ->
{F1,St1} = guard_test(F0, St0),
{Qs1,St2} = lc_tq(Line, Qs0, St1),
diff --git a/lib/stdlib/src/erl_lint.erl b/lib/stdlib/src/erl_lint.erl
index 5ec9b9053a..49b65069b7 100644
--- a/lib/stdlib/src/erl_lint.erl
+++ b/lib/stdlib/src/erl_lint.erl
@@ -27,7 +27,7 @@
-export([module/1,module/2,module/3,format_error/1]).
-export([exprs/2,exprs_opt/3,used_vars/2]). % Used from erl_eval.erl.
--export([is_pattern_expr/1,is_guard_test/1,is_guard_test/2]).
+-export([is_pattern_expr/1,is_guard_test/1,is_guard_test/2,is_guard_test/3]).
-export([is_guard_expr/1]).
-export([bool_option/4,value_option/3,value_option/7]).
@@ -1769,7 +1769,8 @@ bit_size({atom,_Line,all}, _Vt, St, _Check) -> {all,[],St};
bit_size(Size, Vt, St, Check) ->
%% Try to safely evaluate Size if constant to get size,
%% otherwise just treat it as an expression.
- case is_gexpr(Size, St#lint.records) of
+ Info = is_guard_test2_info(St),
+ case is_gexpr(Size, Info) of
true ->
case erl_eval:partial_eval(Size) of
{integer,_ILn,I} -> {I,[],St};
@@ -2004,77 +2005,104 @@ gexpr_list(Es, Vt, St) ->
%% is_guard_test(Expression) -> boolean().
%% Test if a general expression is a guard test.
+%%
+%% Note: Only use this function in contexts where there can be
+%% no definition of a local function that may override a guard BIF
+%% (for example, in the shell).
-spec is_guard_test(Expr) -> boolean() when
Expr :: erl_parse:abstract_expr().
is_guard_test(E) ->
- is_guard_test2(E, dict:new()).
+ is_guard_test2(E, {dict:new(),fun(_) -> false end}).
%% is_guard_test(Expression, Forms) -> boolean().
is_guard_test(Expression, Forms) ->
+ is_guard_test(Expression, Forms, fun(_) -> false end).
+
+
+%% is_guard_test(Expression, Forms, IsOverridden) -> boolean().
+%% Test if a general expression is a guard test.
+%%
+%% IsOverridden({Name,Arity}) should return 'true' if Name/Arity is
+%% a local or imported function in the module. If the abstract code has
+%% passed through erl_expand_records, any call without an explicit
+%% module is to a local function, so IsOverridden can be defined as:
+%%
+%% fun(_) -> true end
+%%
+-spec is_guard_test(Expr, Forms, IsOverridden) -> boolean() when
+ Expr :: erl_parse:abstract_expr(),
+ Forms :: [erl_parse:abstract_form() | erl_parse:form_info()],
+ IsOverridden :: fun((fa()) -> boolean()).
+
+is_guard_test(Expression, Forms, IsOverridden) ->
RecordAttributes = [A || A = {attribute, _, record, _D} <- Forms],
St0 = foldl(fun(Attr0, St1) ->
Attr = set_file(Attr0, "none"),
attribute_state(Attr, St1)
end, start(), RecordAttributes),
- is_guard_test2(set_file(Expression, "nofile"), St0#lint.records).
+ is_guard_test2(set_file(Expression, "nofile"),
+ {St0#lint.records,IsOverridden}).
%% is_guard_test2(Expression, RecordDefs :: dict:dict()) -> boolean().
-is_guard_test2({call,Line,{atom,Lr,record},[E,A]}, RDs) ->
- is_gexpr({call,Line,{atom,Lr,is_record},[E,A]}, RDs);
-is_guard_test2({call,_Line,{atom,_La,Test},As}=Call, RDs) ->
- case erl_internal:type_test(Test, length(As)) of
- true -> is_gexpr_list(As, RDs);
- false -> is_gexpr(Call, RDs)
- end;
-is_guard_test2(G, RDs) ->
+is_guard_test2({call,Line,{atom,Lr,record},[E,A]}, Info) ->
+ is_gexpr({call,Line,{atom,Lr,is_record},[E,A]}, Info);
+is_guard_test2({call,_Line,{atom,_La,Test},As}=Call, {_,IsOverridden}=Info) ->
+ A = length(As),
+ not IsOverridden({Test,A}) andalso
+ case erl_internal:type_test(Test, A) of
+ true -> is_gexpr_list(As, Info);
+ false -> is_gexpr(Call, Info)
+ end;
+is_guard_test2(G, Info) ->
%%Everything else is a guard expression.
- is_gexpr(G, RDs).
+ is_gexpr(G, Info).
%% is_guard_expr(Expression) -> boolean().
%% Test if an expression is a guard expression.
is_guard_expr(E) -> is_gexpr(E, []).
-is_gexpr({var,_L,_V}, _RDs) -> true;
-is_gexpr({char,_L,_C}, _RDs) -> true;
-is_gexpr({integer,_L,_I}, _RDs) -> true;
-is_gexpr({float,_L,_F}, _RDs) -> true;
-is_gexpr({atom,_L,_A}, _RDs) -> true;
-is_gexpr({string,_L,_S}, _RDs) -> true;
-is_gexpr({nil,_L}, _RDs) -> true;
-is_gexpr({cons,_L,H,T}, RDs) -> is_gexpr_list([H,T], RDs);
-is_gexpr({tuple,_L,Es}, RDs) -> is_gexpr_list(Es, RDs);
-%%is_gexpr({struct,_L,_Tag,Es}, RDs) ->
-%% is_gexpr_list(Es, RDs);
-is_gexpr({record_index,_L,_Name,Field}, RDs) ->
- is_gexpr(Field, RDs);
-is_gexpr({record_field,_L,Rec,_Name,Field}, RDs) ->
- is_gexpr_list([Rec,Field], RDs);
-is_gexpr({record,L,Name,Inits}, RDs) ->
- is_gexpr_fields(Inits, L, Name, RDs);
-is_gexpr({bin,_L,Fs}, RDs) ->
+is_gexpr({var,_L,_V}, _Info) -> true;
+is_gexpr({char,_L,_C}, _Info) -> true;
+is_gexpr({integer,_L,_I}, _Info) -> true;
+is_gexpr({float,_L,_F}, _Info) -> true;
+is_gexpr({atom,_L,_A}, _Info) -> true;
+is_gexpr({string,_L,_S}, _Info) -> true;
+is_gexpr({nil,_L}, _Info) -> true;
+is_gexpr({cons,_L,H,T}, Info) -> is_gexpr_list([H,T], Info);
+is_gexpr({tuple,_L,Es}, Info) -> is_gexpr_list(Es, Info);
+%%is_gexpr({struct,_L,_Tag,Es}, Info) ->
+%% is_gexpr_list(Es, Info);
+is_gexpr({record_index,_L,_Name,Field}, Info) ->
+ is_gexpr(Field, Info);
+is_gexpr({record_field,_L,Rec,_Name,Field}, Info) ->
+ is_gexpr_list([Rec,Field], Info);
+is_gexpr({record,L,Name,Inits}, Info) ->
+ is_gexpr_fields(Inits, L, Name, Info);
+is_gexpr({bin,_L,Fs}, Info) ->
all(fun ({bin_element,_Line,E,Sz,_Ts}) ->
- is_gexpr(E, RDs) and (Sz =:= default orelse is_gexpr(Sz, RDs))
+ is_gexpr(E, Info) and (Sz =:= default orelse is_gexpr(Sz, Info))
end, Fs);
-is_gexpr({call,_L,{atom,_Lf,F},As}, RDs) ->
+is_gexpr({call,_L,{atom,_Lf,F},As}, {_,IsOverridden}=Info) ->
A = length(As),
- erl_internal:guard_bif(F, A) andalso is_gexpr_list(As, RDs);
-is_gexpr({call,_L,{remote,_Lr,{atom,_Lm,erlang},{atom,_Lf,F}},As}, RDs) ->
+ not IsOverridden({F,A}) andalso erl_internal:guard_bif(F, A)
+ andalso is_gexpr_list(As, Info);
+is_gexpr({call,_L,{remote,_Lr,{atom,_Lm,erlang},{atom,_Lf,F}},As}, Info) ->
A = length(As),
(erl_internal:guard_bif(F, A) orelse is_gexpr_op(F, A))
- andalso is_gexpr_list(As, RDs);
-is_gexpr({call,L,{tuple,Lt,[{atom,Lm,erlang},{atom,Lf,F}]},As}, RDs) ->
- is_gexpr({call,L,{remote,Lt,{atom,Lm,erlang},{atom,Lf,F}},As}, RDs);
-is_gexpr({op,_L,Op,A}, RDs) ->
- is_gexpr_op(Op, 1) andalso is_gexpr(A, RDs);
-is_gexpr({op,_L,'andalso',A1,A2}, RDs) ->
- is_gexpr_list([A1,A2], RDs);
-is_gexpr({op,_L,'orelse',A1,A2}, RDs) ->
- is_gexpr_list([A1,A2], RDs);
-is_gexpr({op,_L,Op,A1,A2}, RDs) ->
- is_gexpr_op(Op, 2) andalso is_gexpr_list([A1,A2], RDs);
-is_gexpr(_Other, _RDs) -> false.
+ andalso is_gexpr_list(As, Info);
+is_gexpr({call,L,{tuple,Lt,[{atom,Lm,erlang},{atom,Lf,F}]},As}, Info) ->
+ is_gexpr({call,L,{remote,Lt,{atom,Lm,erlang},{atom,Lf,F}},As}, Info);
+is_gexpr({op,_L,Op,A}, Info) ->
+ is_gexpr_op(Op, 1) andalso is_gexpr(A, Info);
+is_gexpr({op,_L,'andalso',A1,A2}, Info) ->
+ is_gexpr_list([A1,A2], Info);
+is_gexpr({op,_L,'orelse',A1,A2}, Info) ->
+ is_gexpr_list([A1,A2], Info);
+is_gexpr({op,_L,Op,A1,A2}, Info) ->
+ is_gexpr_op(Op, 2) andalso is_gexpr_list([A1,A2], Info);
+is_gexpr(_Other, _Info) -> false.
is_gexpr_op(Op, A) ->
try erl_internal:op_type(Op, A) of
@@ -2086,14 +2114,14 @@ is_gexpr_op(Op, A) ->
catch _:_ -> false
end.
-is_gexpr_list(Es, RDs) -> all(fun (E) -> is_gexpr(E, RDs) end, Es).
+is_gexpr_list(Es, Info) -> all(fun (E) -> is_gexpr(E, Info) end, Es).
-is_gexpr_fields(Fs, L, Name, RDs) ->
+is_gexpr_fields(Fs, L, Name, {RDs,_}=Info) ->
IFs = case dict:find(Name, RDs) of
{ok,{_Line,Fields}} -> Fs ++ init_fields(Fs, L, Fields);
error -> Fs
end,
- all(fun ({record_field,_Lf,_Name,V}) -> is_gexpr(V, RDs);
+ all(fun ({record_field,_Lf,_Name,V}) -> is_gexpr(V, Info);
(_Other) -> false end, IFs).
%% exprs(Sequence, VarTable, State) ->
@@ -3197,7 +3225,8 @@ lc_quals([{b_generate,_Line,P,E} | Qs], Vt0, Uvt0, St0) ->
{Vt,Uvt,St} = handle_generator(P,E,Vt0,Uvt0,St1),
lc_quals(Qs, Vt, Uvt, St);
lc_quals([F|Qs], Vt, Uvt, St0) ->
- {Fvt,St1} = case is_guard_test2(F, St0#lint.records) of
+ Info = is_guard_test2_info(St0),
+ {Fvt,St1} = case is_guard_test2(F, Info) of
true -> guard_test(F, Vt, St0);
false -> expr(F, Vt, St0)
end,
@@ -3205,6 +3234,12 @@ lc_quals([F|Qs], Vt, Uvt, St0) ->
lc_quals([], Vt, Uvt, St) ->
{Vt, Uvt, St}.
+is_guard_test2_info(#lint{records=RDs,locals=Locals,imports=Imports}) ->
+ {RDs,fun(FA) ->
+ is_local_function(Locals, FA) orelse
+ is_imported_function(Imports, FA)
+ end}.
+
handle_generator(P,E,Vt,Uvt,St0) ->
{Evt,St1} = expr(E, Vt, St0),
%% Forget variables local to E immediately.
diff --git a/lib/stdlib/src/qlc_pt.erl b/lib/stdlib/src/qlc_pt.erl
index 869b003668..28221ea75f 100644
--- a/lib/stdlib/src/qlc_pt.erl
+++ b/lib/stdlib/src/qlc_pt.erl
@@ -41,6 +41,7 @@
}).
-record(state, {imp,
+ overridden,
maxargs,
records,
xwarnings = [],
@@ -184,7 +185,9 @@ initiate(Forms0, Imported) ->
exclude_integers_from_unique_line_numbers(Forms0, NodeInfo),
?DEBUG("node info0 ~p~n",
[lists:sort(ets:tab2list(NodeInfo))]),
+ IsOverridden = set_up_overridden(Forms0),
State0 = #state{imp = Imported,
+ overridden = IsOverridden,
maxargs = ?EVAL_MAX_NUM_OF_ARGS,
records = record_attributes(Forms0),
node_info = NodeInfo},
@@ -1519,36 +1522,35 @@ filter_info(FilterData, AllIVs, Dependencies, State) ->
%% to be placed after further generators (the docs states otherwise, but
%% this seems to be common practice).
filter_list(FilterData, Dependencies, State) ->
- RDs = State#state.records,
- sel_gf(FilterData, 1, Dependencies, RDs, [], []).
+ sel_gf(FilterData, 1, Dependencies, State, [], []).
sel_gf([], _N, _Deps, _RDs, _Gens, _Gens1) ->
[];
-sel_gf([{#qid{no = N}=Id,{fil,F}}=Fil | FData], N, Deps, RDs, Gens, Gens1) ->
- case erl_lint:is_guard_test(F, RDs) of
+sel_gf([{#qid{no = N}=Id,{fil,F}}=Fil | FData], N, Deps, State, Gens, Gens1) ->
+ case is_guard_test(F, State) of
true ->
{Id,GIds} = lists:keyfind(Id, 1, Deps),
case length(GIds) =< 1 of
true ->
case generators_in_scope(GIds, Gens1) of
true ->
- [Fil|sel_gf(FData, N+1, Deps, RDs, Gens, Gens1)];
+ [Fil|sel_gf(FData, N+1, Deps, State, Gens, Gens1)];
false ->
- sel_gf(FData, N + 1, Deps, RDs, [], [])
+ sel_gf(FData, N + 1, Deps, State, [], [])
end;
false ->
case generators_in_scope(GIds, Gens) of
true ->
- [Fil | sel_gf(FData, N + 1, Deps, RDs, Gens, [])];
+ [Fil | sel_gf(FData, N + 1, Deps, State, Gens, [])];
false ->
- sel_gf(FData, N + 1, Deps, RDs, [], [])
+ sel_gf(FData, N + 1, Deps, State, [], [])
end
end;
false ->
- sel_gf(FData, N + 1, Deps, RDs, [], [])
+ sel_gf(FData, N + 1, Deps, State, [], [])
end;
-sel_gf(FData, N, Deps, RDs, Gens, Gens1) ->
- sel_gf(FData, N + 1, Deps, RDs, [N | Gens], [N | Gens1]).
+sel_gf(FData, N, Deps, State, Gens, Gens1) ->
+ sel_gf(FData, N + 1, Deps, State, [N | Gens], [N | Gens1]).
generators_in_scope(GenIds, GenNumbers) ->
lists:all(fun(#qid{no=N}) -> lists:member(N, GenNumbers) end, GenIds).
@@ -2483,7 +2485,7 @@ filter(E, L, QIVs, S, RL, Fun, Go, GoI, IVs, State) ->
%% This is the "guard semantics" used in ordinary list
%% comprehension: if a filter looks like a guard test, it returns
%% 'false' rather than fails.
- Body = case erl_lint:is_guard_test(E, State#state.records) of
+ Body = case is_guard_test(E, State) of
true ->
CT = {clause,L,[],[[E]],[{call,L,?V(Fun),NAsT}]},
CF = {clause,L,[],[[?A(true)]],[{call,L,?V(Fun),NAsF}]},
@@ -2887,6 +2889,26 @@ family_list(L) ->
family(L) ->
sofs:relation_to_family(sofs:relation(L)).
+is_guard_test(E, #state{records = RDs, overridden = IsOverridden}) ->
+ erl_lint:is_guard_test(E, RDs, IsOverridden).
+
+%% In code that has been run through erl_expand_records, a guard
+%% test will never contain calls without an explicit module
+%% prefix. Unfortunately, this module runs *some* of the code
+%% through erl_expand_records, but not all of it.
+%%
+%% Therefore, we must set up our own list of local and imported functions
+%% that will override a BIF with the same name.
+
+set_up_overridden(Forms) ->
+ Locals = [{Name,Arity} || {function,_,Name,Arity,_} <- Forms],
+ Imports0 = [Fs || {attribute,_,import,Fs} <- Forms],
+ Imports1 = lists:flatten(Imports0),
+ Imports2 = [Fs || {_,Fs} <- Imports1],
+ Imports = lists:flatten(Imports2),
+ Overridden = gb_sets:from_list(Imports ++ Locals),
+ fun(FA) -> gb_sets:is_element(FA, Overridden) end.
+
-ifdef(debug).
display_forms(Forms) ->
io:format("Forms ***~n"),