%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2005-2011. 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%
%%
%% Purpose : Expand records into tuples.
%% N.B. Although structs (tagged tuples) are not yet allowed in the
%% language there is code included in pattern/2 and expr/3 (commented out)
%% that handles them.
-module(erl_expand_records).
-export([module/2]).
-import(lists, [map/2,foldl/3,foldr/3,sort/1,reverse/1,duplicate/2]).
-record(exprec, {compile=[], % Compile flags
vcount=0, % Variable counter
imports=[], % Imports
records=dict:new(), % Record definitions
trecords=sets:new(), % Typed records
uses_types=false, % Are there -spec or -type in the module
strict_ra=[], % strict record accesses
checked_ra=[] % successfully accessed records
}).
-spec(module(AbsForms, CompileOptions) -> AbsForms when
AbsForms :: [erl_parse:abstract_form()],
CompileOptions :: [compile:option()]).
%% Is is assumed that Fs is a valid list of forms. It should pass
%% erl_lint without errors.
module(Fs0, Opts0) ->
Opts = compiler_options(Fs0) ++ Opts0,
TRecs = typed_records(Fs0),
UsesTypes = uses_types(Fs0),
St0 = #exprec{compile = Opts, trecords = TRecs, uses_types = UsesTypes},
{Fs,_St} = forms(Fs0, St0),
Fs.
compiler_options(Forms) ->
lists:flatten([C || {attribute,_,compile,C} <- Forms]).
typed_records(Fs) ->
typed_records(Fs, sets:new()).
typed_records([{attribute,_L,type,{{record, Name},_Defs,[]}} | Fs], Trecs) ->
typed_records(Fs, sets:add_element(Name, Trecs));
typed_records([_|Fs], Trecs) ->
typed_records(Fs, Trecs);
typed_records([], Trecs) ->
Trecs.
uses_types([{attribute,_L,spec,_}|_]) -> true;
uses_types([{attribute,_L,type,_}|_]) -> true;
uses_types([{attribute,_L,opaque,_}|_]) -> true;
uses_types([_|Fs]) -> uses_types(Fs);
uses_types([]) -> false.
forms([{attribute,L,record,{Name,Defs}} | Fs], St0) ->
NDefs = normalise_fields(Defs),
St = St0#exprec{records=dict:store(Name, NDefs, St0#exprec.records)},
{Fs1, St1} = forms(Fs, St),
%% Check if we need to keep the record information for usage in types.
case St#exprec.uses_types of
true ->
case sets:is_element(Name, St#exprec.trecords) of
true -> {Fs1, St1};
false -> {[{attribute,L,type,{{record,Name},Defs,[]}}|Fs1], St1}
end;
false ->
{Fs1, St1}
end;
forms([{attribute,L,import,Is} | Fs0], St0) ->
St1 = import(Is, St0),
{Fs,St2} = forms(Fs0, St1),
{[{attribute,L,import,Is} | Fs], St2};
forms([{function,L,N,A,Cs0} | Fs0], St0) ->
{Cs,St1} = clauses(Cs0, St0),
{Fs,St2} = forms(Fs0, St1),
{[{function,L,N,A,Cs} | Fs],St2};
forms([F | Fs0], St0) ->
{Fs,St} = forms(Fs0, St0),
{[F | Fs], St};
forms([], St) -> {[],St}.
clauses([{clause,Line,H0,G0,B0} | Cs0], St0) ->
{H1,St1} = head(H0, St0),
{G1,St2} = guard(G0, St1),
{H,G} = optimize_is_record(H1, G1, St2),
{B,St3} = exprs(B0, St2),
{Cs,St4} = clauses(Cs0, St3),
{[{clause,Line,H,G,B} | Cs],St4};
clauses([], St) -> {[],St}.
head(As, St) -> pattern_list(As, St).
pattern({var,_,'_'}=Var, St) ->
{Var,St};
pattern({var,_,_}=Var, St) ->
{Var,St};
pattern({char,_,_}=Char, St) ->
{Char,St};
pattern({integer,_,_}=Int, St) ->
{Int,St};
pattern({float,_,_}=Float, St) ->
{Float,St};
pattern({atom,_,_}=Atom, St) ->
{Atom,St};
pattern({string,_,_}=String, St) ->
{String,St};
pattern({nil,_}=Nil, St) ->
{Nil,St};
pattern({cons,Line,H,T}, St0) ->
{TH,St1} = pattern(H, St0),
{TT,St2} = pattern(T, St1),
{{cons,Line,TH,TT},St2};
pattern({tuple,Line,Ps}, St0) ->
{TPs,St1} = pattern_list(Ps, St0),
{{tuple,Line,TPs},St1};
%%pattern({struct,Line,Tag,Ps}, St0) ->
%% {TPs,TPsvs,St1} = pattern_list(Ps, St0),
%% {{struct,Line,Tag,TPs},TPsvs,St1};
pattern({record_field,_,_,_}=M, St) ->
{M,St}; % must be a package name
pattern({record_index,Line,Name,Field}, St) ->
{index_expr(Line, Field, Name, record_fields(Name, St)),St};
pattern({record,Line,Name,Pfs}, St0) ->
Fs = record_fields(Name, St0),
{TMs,St1} = pattern_list(pattern_fields(Fs, Pfs), St0),
{{tuple,Line,[{atom,Line,Name} | TMs]},St1};
pattern({bin,Line,Es0}, St0) ->
{Es1,St1} = pattern_bin(Es0, St0),
{{bin,Line,Es1},St1};
pattern({match,Line,Pat1, Pat2}, St0) ->
{TH,St1} = pattern(Pat2, St0),
{TT,St2} = pattern(Pat1, St1),
{{match,Line,TT,TH},St2};
pattern({op,Line,Op,A0}, St0) ->
{A,St1} = pattern(A0, St0),
{{op,Line,Op,A},St1};
pattern({op,Line,Op,L0,R0}, St0) ->
{L,St1} = pattern(L0, St0),
{R,St2} = pattern(R0, St1),
{{op,Line,Op,L,R},St2}.
pattern_list([P0 | Ps0], St0) ->
{P,St1} = pattern(P0, St0),
{Ps,St2} = pattern_list(Ps0, St1),
{[P | Ps],St2};
pattern_list([], St) -> {[],St}.
guard([G0 | Gs0], St0) ->
{G,St1} = guard_tests(G0, St0),
{Gs,St2} = guard(Gs0, St1),
{[G | Gs],St2};
guard([], St) -> {[],St}.
guard_tests(Gts0, St0) ->
{Gts1,St1} = guard_tests1(Gts0, St0),
{Gts1,St1#exprec{checked_ra = []}}.
guard_tests1([Gt0 | Gts0], St0) ->
{Gt1,St1} = guard_test(Gt0, St0),
{Gts1,St2} = guard_tests1(Gts0, St1),
{[Gt1 | Gts1],St2};
guard_tests1([], St) -> {[],St}.
guard_test(G0, St0) ->
in_guard(fun() ->
{G1,St1} = guard_test1(G0, St0),
strict_record_access(G1, St1)
end).
%% Normalising guard tests ensures that none of the Boolean operands
%% created by strict_record_access/2 calls any of the old guard tests.
guard_test1({call,Line,{atom,Lt,Tname},As}, St) ->
Test = {atom,Lt,normalise_test(Tname, length(As))},
expr({call,Line,Test,As}, St);
guard_test1(Test, St) ->
expr(Test, St).
normalise_test(atom, 1) -> is_atom;
normalise_test(binary, 1) -> is_binary;
normalise_test(float, 1) -> is_float;
normalise_test(function, 1) -> is_function;
normalise_test(integer, 1) -> is_integer;
normalise_test(list, 1) -> is_list;
normalise_test(number, 1) -> is_number;
normalise_test(pid, 1) -> is_pid;
normalise_test(port, 1) -> is_port;
normalise_test(record, 2) -> is_record;
normalise_test(reference, 1) -> is_reference;
normalise_test(tuple, 1) -> is_tuple;
normalise_test(Name, _) -> Name.
is_in_guard() ->
get(erl_expand_records_in_guard) =/= undefined.
in_guard(F) ->
undefined = put(erl_expand_records_in_guard, true),
Res = F(),
true = erase(erl_expand_records_in_guard),
Res.
%% record_test(Line, Term, Name, Vs, St) -> TransformedExpr
%% Generate code for is_record/1.
record_test(Line, Term, Name, St) ->
case is_in_guard() of
false ->
record_test_in_body(Line, Term, Name, St);
true ->
record_test_in_guard(Line, Term, Name, St)
end.
record_test_in_guard(Line, Term, Name, St) ->
case not_a_tuple(Term) of
true ->
%% In case that later optimization passes have been turned off.
expr({atom,Line,false}, St);
false ->
Fs = record_fields(Name, St),
NLine = neg_line(Line),
expr({call,NLine,{remote,NLine,{atom,NLine,erlang},{atom,NLine,is_record}},
[Term,{atom,Line,Name},{integer,Line,length(Fs)+1}]},
St)
end.
not_a_tuple({atom,_,_}) -> true;
not_a_tuple({integer,_,_}) -> true;
not_a_tuple({float,_,_}) -> true;
not_a_tuple({nil,_}) -> true;
not_a_tuple({cons,_,_,_}) -> true;
not_a_tuple({char,_,_}) -> true;
not_a_tuple({string,_,_}) -> true;
not_a_tuple({record_index,_,_,_}) -> true;
not_a_tuple({bin,_,_}) -> true;
not_a_tuple({op,_,_,_}) -> true;
not_a_tuple({op,_,_,_,_}) -> true;
not_a_tuple(_) -> false.
record_test_in_body(Line, Expr, Name, St0) ->
%% As Expr may have side effects, we must evaluate it
%% first and bind the value to a new variable.
%% We must use also handle the case that Expr does not
%% evaluate to a tuple properly.
Fs = record_fields(Name, St0),
{Var,St} = new_var(Line, St0),
NLine = neg_line(Line),
expr({block,Line,
[{match,Line,Var,Expr},
{call,NLine,{remote,NLine,{atom,NLine,erlang},
{atom,NLine,is_record}},
[Var,{atom,Line,Name},{integer,Line,length(Fs)+1}]}]}, St).
exprs([E0 | Es0], St0) ->
{E,St1} = expr(E0, St0),
{Es,St2} = exprs(Es0, St1),
{[E | Es],St2};
exprs([], St) -> {[],St}.
expr({var,_,_}=Var, St) ->
{Var,St};
expr({char,_,_}=Char, St) ->
{Char,St};
expr({integer,_,_}=Int, St) ->
{Int,St};
expr({float,_,_}=Float, St) ->
{Float,St};
expr({atom,_,_}=Atom, St) ->
{Atom,St};
expr({string,_,_}=String, St) ->
{String,St};
expr({nil,_}=Nil, St) ->
{Nil,St};
expr({cons,Line,H0,T0}, St0) ->
{H,St1} = expr(H0, St0),
{T,St2} = expr(T0, St1),
{{cons,Line,H,T},St2};
expr({lc,Line,E0,Qs0}, St0) ->
{Qs1,St1} = lc_tq(Line, Qs0, St0),
{E1,St2} = expr(E0, St1),
{{lc,Line,E1,Qs1},St2};
expr({bc,Line,E0,Qs0}, St0) ->
{Qs1,St1} = lc_tq(Line, Qs0, St0),
{E1,St2} = expr(E0, St1),
{{bc,Line,E1,Qs1},St2};
expr({tuple,Line,Es0}, St0) ->
{Es1,St1} = expr_list(Es0, St0),
{{tuple,Line,Es1},St1};
%%expr({struct,Line,Tag,Es0}, Vs, St0) ->
%% {Es1,Esvs,Esus,St1} = expr_list(Es0, Vs, St0),
%% {{struct,Line,Tag,Es1},Esvs,Esus,St1};
expr({record_field,_,_,_}=M, St) ->
{M,St}; % must be a package name
expr({record_index,Line,Name,F}, St) ->
I = index_expr(Line, F, Name, record_fields(Name, St)),
expr(I, St);
expr({record,Line,Name,Is}, St) ->
expr({tuple,Line,[{atom,Line,Name} |
record_inits(record_fields(Name, St), Is)]},
St);
expr({record_field,Line,R,Name,F}, St) ->
get_record_field(Line, R, F, Name, St);
expr({record,_,R,Name,Us}, St0) ->
{Ue,St1} = record_update(R, Name, record_fields(Name, St0), Us, St0),
expr(Ue, St1);
expr({bin,Line,Es0}, St0) ->
{Es1,St1} = expr_bin(Es0, St0),
{{bin,Line,Es1},St1};
expr({block,Line,Es0}, St0) ->
{Es,St1} = exprs(Es0, St0),
{{block,Line,Es},St1};
expr({'if',Line,Cs0}, St0) ->
{Cs,St1} = clauses(Cs0, St0),
{{'if',Line,Cs},St1};
expr({'case',Line,E0,Cs0}, St0) ->
{E,St1} = expr(E0, St0),
{Cs,St2} = clauses(Cs0, St1),
{{'case',Line,E,Cs},St2};
expr({'receive',Line,Cs0}, St0) ->
{Cs,St1} = clauses(Cs0, St0),
{{'receive',Line,Cs},St1};
expr({'receive',Line,Cs0,To0,ToEs0}, St0) ->
{To,St1} = expr(To0, St0),
{ToEs,St2} = exprs(ToEs0, St1),
{Cs,St3} = clauses(Cs0, St2),
{{'receive',Line,Cs,To,ToEs},St3};
expr({'fun',_,{function,_F,_A}}=Fun, St) ->
{Fun,St};
expr({'fun',_,{function,_M,_F,_A}}=Fun, St) ->
{Fun,St};
expr({'fun',Line,{clauses,Cs0}}, St0) ->
{Cs,St1} = clauses(Cs0, St0),
{{'fun',Line,{clauses,Cs}},St1};
expr({call,Line,{atom,_,is_record},[A,{atom,_,Name}]}, St) ->
record_test(Line, A, Name, St);
expr({call,Line,{remote,_,{atom,_,erlang},{atom,_,is_record}},
[A,{atom,_,Name}]}, St) ->
record_test(Line, A, Name, St);
expr({call,Line,{tuple,_,[{atom,_,erlang},{atom,_,is_record}]},
[A,{atom,_,Name}]}, St) ->
record_test(Line, A, Name, St);
expr({call,Line,{atom,_La,N}=Atom,As0}, St0) ->
{As,St1} = expr_list(As0, St0),
Ar = length(As),
case erl_internal:bif(N, Ar) of
true ->
{{call,Line,Atom,As},St1};
false ->
case imported(N, Ar, St1) of
{yes,_Mod} ->
{{call,Line,Atom,As},St1};
no ->
case {N,Ar} of
{record_info,2} ->
record_info_call(Line, As, St1);
_ ->
{{call,Line,Atom,As},St1}
end
end
end;
expr({call,Line,{record_field,_,_,_}=M,As0}, St0) ->
{As,St1} = expr_list(As0, St0),
{{call,Line,M,As},St1};
expr({call,Line,{remote,Lr,M,F},As0}, St0) ->
{[M1,F1 | As1],St1} = expr_list([M,F | As0], St0),
{{call,Line,{remote,Lr,M1,F1},As1},St1};
expr({call,Line,{tuple,Lt,[{atom,_,_}=M,{atom,_,_}=F]},As0}, St0) ->
{As,St1} = expr_list(As0, St0),
{{call,Line,{tuple,Lt,[M,F]},As},St1};
expr({call,Line,F,As0}, St0) ->
{[Fun1 | As1],St1} = expr_list([F | As0], St0),
{{call,Line,Fun1,As1},St1};
expr({'try',Line,Es0,Scs0,Ccs0,As0}, St0) ->
{Es1,St1} = exprs(Es0, St0),
{Scs1,St2} = clauses(Scs0, St1),
{Ccs1,St3} = clauses(Ccs0, St2),
{As1,St4} = exprs(As0, St3),
{{'try',Line,Es1,Scs1,Ccs1,As1},St4};
expr({'catch',Line,E0}, St0) ->
{E,St1} = expr(E0, St0),
{{'catch',Line,E},St1};
expr({match,Line,P0,E0}, St0) ->
{E,St1} = expr(E0, St0),
{P,St2} = pattern(P0, St1),
{{match,Line,P,E},St2};
expr({op,Line,'not',A0}, St0) ->
{A,St1} = bool_operand(A0, St0),
{{op,Line,'not',A},St1};
expr({op,Line,Op,A0}, St0) ->
{A,St1} = expr(A0, St0),
{{op,Line,Op,A},St1};
expr({op,Line,Op,L0,R0}, St0) when Op =:= 'and';
Op =:= 'or' ->
{L,St1} = bool_operand(L0, St0),
{R,St2} = bool_operand(R0, St1),
{{op,Line,Op,L,R},St2};
expr({op,Line,Op,L0,R0}, St0) when Op =:= 'andalso';
Op =:= 'orelse' ->
{L,St1} = bool_operand(L0, St0),
{R,St2} = bool_operand(R0, St1),
{{op,Line,Op,L,R},St2#exprec{checked_ra = St1#exprec.checked_ra}};
expr({op,Line,Op,L0,R0}, St0) ->
{L,St1} = expr(L0, St0),
{R,St2} = expr(R0, St1),
{{op,Line,Op,L,R},St2}.
expr_list([E0 | Es0], St0) ->
{E,St1} = expr(E0, St0),
{Es,St2} = expr_list(Es0, St1),
{[E | Es],St2};
expr_list([], St) -> {[],St}.
bool_operand(E0, St0) ->
{E1,St1} = expr(E0, St0),
strict_record_access(E1, St1).
strict_record_access(E, #exprec{strict_ra = []} = St) ->
{E, St};
strict_record_access(E0, St0) ->
#exprec{strict_ra = StrictRA, checked_ra = CheckedRA} = St0,
{New,NC} = lists:foldl(fun ({Key,_L,_R,_Sz}=A, {L,C}) ->
case lists:keymember(Key, 1, C) of
true -> {L,C};
false -> {[A|L],[A|C]}
end
end, {[],CheckedRA}, StrictRA),
E1 = if New =:= [] -> E0; true -> conj(New, E0) end,
St1 = St0#exprec{strict_ra = [], checked_ra = NC},
expr(E1, St1).
%% Make it look nice (?) when compiled with the 'E' flag
%% ('and'/2 is left recursive).
conj([], _E) ->
empty;
conj([{{Name,_Rp},L,R,Sz} | AL], E) ->
NL = neg_line(L),
T1 = {op,NL,'orelse',
{call,NL,{atom,NL,is_record},[R,{atom,NL,Name},{integer,NL,Sz}]},
{atom,NL,fail}},
T2 = case conj(AL, none) of
empty -> T1;
C -> {op,NL,'and',C,T1}
end,
case E of
none ->
case T2 of
{op,_,'and',_,_} ->
T2;
_ ->
%% Wrap the 'orelse' expression in an dummy 'and true' to make
%% sure that the entire guard fails if the 'orelse'
%% expression returns 'fail'. ('orelse' used to verify
%% that its right operand was a boolean, but that is no
%% longer the case.)
{op,NL,'and',T2,{atom,NL,true}}
end;
_ ->
{op,NL,'and',T2,E}
end.
%% lc_tq(Line, Qualifiers, State) ->
%% {[TransQual],State'}
lc_tq(Line, [{generate,Lg,P0,G0} | Qs0], St0) ->
{G1,St1} = expr(G0, St0),
{P1,St2} = pattern(P0, St1),
{Qs1,St3} = lc_tq(Line, Qs0, St2),
{[{generate,Lg,P1,G1} | Qs1],St3};
lc_tq(Line, [{b_generate,Lg,P0,G0} | Qs0], St0) ->
{G1,St1} = expr(G0, 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) ->
%% Allow record/2 and expand out as guard test.
case erl_lint:is_guard_test(F0) of
true ->
{F1,St1} = guard_test(F0, St0),
{Qs1,St2} = lc_tq(Line, Qs0, St1),
{[F1|Qs1],St2};
false ->
{F1,St1} = expr(F0, St0),
{Qs1,St2} = lc_tq(Line, Qs0, St1),
{[F1 | Qs1],St2}
end;
lc_tq(_Line, [], St0) ->
{[],St0#exprec{checked_ra = []}}.
%% normalise_fields([RecDef]) -> [Field].
%% Normalise the field definitions to always have a default value. If
%% none has been given then use 'undefined'.
normalise_fields(Fs) ->
map(fun ({record_field,Lf,Field}) ->
{record_field,Lf,Field,{atom,Lf,undefined}};
({typed_record_field,{record_field,Lf,Field},_Type}) ->
{record_field,Lf,Field,{atom,Lf,undefined}};
({typed_record_field,Field,_Type}) ->
Field;
(F) -> F
end, Fs).
%% record_fields(RecordName, State)
%% find_field(FieldName, Fields)
record_fields(R, St) -> dict:fetch(R, St#exprec.records).
find_field(F, [{record_field,_,{atom,_,F},Val} | _]) -> {ok,Val};
find_field(F, [_ | Fs]) -> find_field(F, Fs);
find_field(_, []) -> error.
%% field_names(RecFields) -> [Name].
%% Return a list of the field names structures.
field_names(Fs) ->
map(fun ({record_field,_,Field,_Val}) -> Field end, Fs).
%% index_expr(Line, FieldExpr, Name, Fields) -> IndexExpr.
%% Return an expression which evaluates to the index of a
%% field. Currently only handle the case where the field is an
%% atom. This expansion must be passed through expr again.
index_expr(Line, {atom,_,F}, _Name, Fs) ->
{integer,Line,index_expr(F, Fs, 2)}.
index_expr(F, [{record_field,_,{atom,_,F},_} | _], I) -> I;
index_expr(F, [_ | Fs], I) -> index_expr(F, Fs, I+1).
%% get_record_field(Line, RecExpr, FieldExpr, Name, St) -> {Expr,St'}.
%% Return an expression which verifies that the type of record
%% is correct and then returns the value of the field.
%% This expansion must be passed through expr again.
get_record_field(Line, R, Index, Name, St) ->
case strict_record_tests(St#exprec.compile) of
false ->
sloppy_get_record_field(Line, R, Index, Name, St);
true ->
strict_get_record_field(Line, R, Index, Name, St)
end.
strict_get_record_field(Line, R, {atom,_,F}=Index, Name, St0) ->
case is_in_guard() of
false -> %Body context.
{Var,St} = new_var(Line, St0),
Fs = record_fields(Name, St),
I = index_expr(F, Fs, 2),
P = record_pattern(2, I, Var, length(Fs)+1, Line, [{atom,Line,Name}]),
NLine = neg_line(Line),
E = {'case',NLine,R,
[{clause,NLine,[{tuple,NLine,P}],[],[Var]},
{clause,NLine,[{var,NLine,'_'}],[],
[{call,NLine,{remote,NLine,
{atom,NLine,erlang},
{atom,NLine,error}},
[{tuple,NLine,[{atom,NLine,badrecord},{atom,NLine,Name}]}]}]}]},
expr(E, St);
true -> %In a guard.
Fs = record_fields(Name, St0),
I = index_expr(Line, Index, Name, Fs),
{ExpR,St1} = expr(R, St0),
%% Just to make comparison simple:
ExpRp = erl_lint:modify_line(ExpR, fun(_L) -> 0 end),
RA = {{Name,ExpRp},Line,ExpR,length(Fs)+1},
St2 = St1#exprec{strict_ra = [RA | St1#exprec.strict_ra]},
{{call,Line,{atom,Line,element},[I,ExpR]},St2}
end.
record_pattern(I, I, Var, Sz, Line, Acc) ->
record_pattern(I+1, I, Var, Sz, Line, [Var | Acc]);
record_pattern(Cur, I, Var, Sz, Line, Acc) when Cur =< Sz ->
record_pattern(Cur+1, I, Var, Sz, Line, [{var,Line,'_'} | Acc]);
record_pattern(_, _, _, _, _, Acc) -> reverse(Acc).
sloppy_get_record_field(Line, R, Index, Name, St) ->
Fs = record_fields(Name, St),
I = index_expr(Line, Index, Name, Fs),
expr({call,Line,{atom,Line,element},[I,R]}, St).
strict_record_tests([strict_record_tests | _]) -> true;
strict_record_tests([no_strict_record_tests | _]) -> false;
strict_record_tests([_ | Os]) -> strict_record_tests(Os);
strict_record_tests([]) -> true. %Default.
strict_record_updates([strict_record_updates | _]) -> true;
strict_record_updates([no_strict_record_updates | _]) -> false;
strict_record_updates([_ | Os]) -> strict_record_updates(Os);
strict_record_updates([]) -> false. %Default.
%% pattern_fields([RecDefField], [Match]) -> [Pattern].
%% Build a list of match patterns for the record tuple elements.
%% This expansion must be passed through pattern again. N.B. We are
%% scanning the record definition field list!
pattern_fields(Fs, Ms) ->
Wildcard = record_wildcard_init(Ms),
map(fun ({record_field,L,{atom,_,F},_}) ->
case find_field(F, Ms) of
{ok,Match} -> Match;
error when Wildcard =:= none -> {var,L,'_'};
error -> Wildcard
end
end, Fs).
%% record_inits([RecDefField], [Init]) -> [InitExpr].
%% Build a list of initialisation expressions for the record tuple
%% elements. This expansion must be passed through expr
%% again. N.B. We are scanning the record definition field list!
record_inits(Fs, Is) ->
WildcardInit = record_wildcard_init(Is),
map(fun ({record_field,_,{atom,_,F},D}) ->
case find_field(F, Is) of
{ok,Init} -> Init;
error when WildcardInit =:= none -> D;
error -> WildcardInit
end
end, Fs).
record_wildcard_init([{record_field,_,{var,_,'_'},D} | _]) -> D;
record_wildcard_init([_ | Is]) -> record_wildcard_init(Is);
record_wildcard_init([]) -> none.
%% record_update(Record, RecordName, [RecDefField], [Update], State) ->
%% {Expr,State'}
%% Build an expression to update fields in a record returning a new
%% record. Try to be smart and optimise this. This expansion must be
%% passed through expr again.
record_update(R, Name, Fs, Us0, St0) ->
Line = element(2, R),
{Pre,Us,St1} = record_exprs(Us0, St0),
Nf = length(Fs), %# of record fields
Nu = length(Us), %# of update fields
Nc = Nf - Nu, %# of copy fields
%% We need a new variable for the record expression
%% to guarantee that it is only evaluated once.
{Var,St2} = new_var(Line, St1),
StrictUpdates = strict_record_updates(St2#exprec.compile),
%% Try to be intelligent about which method of updating record to use.
{Update,St} =
if
Nu =:= 0 ->
record_match(Var, Name, Line, Fs, Us, St2);
Nu =< Nc, not StrictUpdates -> %Few fields updated
{record_setel(Var, Name, Fs, Us), St2};
true -> %The wide area inbetween
record_match(Var, Name, element(2, hd(Us)), Fs, Us, St2)
end,
{{block,Line,Pre ++ [{match,Line,Var,R},Update]},St}.
%% record_match(Record, RecordName, [RecDefField], [Update], State)
%% Build a 'case' expression to modify record fields.
record_match(R, Name, Lr, Fs, Us, St0) ->
{Ps,News,St1} = record_upd_fs(Fs, Us, St0),
NLr = neg_line(Lr),
{{'case',Lr,R,
[{clause,Lr,[{tuple,Lr,[{atom,Lr,Name} | Ps]}],[],
[{tuple,Lr,[{atom,Lr,Name} | News]}]},
{clause,NLr,[{var,NLr,'_'}],[],
[call_error(NLr, {tuple,NLr,[{atom,NLr,badrecord},{atom,NLr,Name}]})]}
]},
St1}.
record_upd_fs([{record_field,Lf,{atom,_La,F},_Val} | Fs], Us, St0) ->
{P,St1} = new_var(Lf, St0),
{Ps,News,St2} = record_upd_fs(Fs, Us, St1),
case find_field(F, Us) of
{ok,New} -> {[P | Ps],[New | News],St2};
error -> {[P | Ps],[P | News],St2}
end;
record_upd_fs([], _, St) -> {[],[],St}.
%% record_setel(Record, RecordName, [RecDefField], [Update])
%% Build a nested chain of setelement calls to build the
%% updated record tuple.
record_setel(R, Name, Fs, Us0) ->
Us1 = foldl(fun ({record_field,Lf,Field,Val}, Acc) ->
{integer,_,FieldIndex} = I = index_expr(Lf, Field, Name, Fs),
[{FieldIndex,{I,Lf,Val}} | Acc]
end, [], Us0),
Us2 = sort(Us1),
Us = [T || {_,T} <- Us2],
Lr = element(2, hd(Us)),
Wildcards = duplicate(length(Fs), {var,Lr,'_'}),
NLr = neg_line(Lr),
{'case',Lr,R,
[{clause,Lr,[{tuple,Lr,[{atom,Lr,Name} | Wildcards]}],[],
[foldr(fun ({I,Lf,Val}, Acc) ->
{call,Lf,{atom,Lf,setelement},[I,Acc,Val]} end,
R, Us)]},
{clause,NLr,[{var,NLr,'_'}],[],
[call_error(NLr, {tuple,NLr,[{atom,NLr,badrecord},{atom,NLr,Name}]})]}]}.
%% Expand a call to record_info/2. We have checked that it is not
%% shadowed by an import.
record_info_call(Line, [{atom,_Li,Info},{atom,_Ln,Name}], St) ->
case Info of
size ->
{{integer,Line,1+length(record_fields(Name, St))},St};
fields ->
{make_list(field_names(record_fields(Name, St)), Line),St}
end.
%% Break out expressions from an record update list and bind to new
%% variables. The idea is that we will evaluate all update expressions
%% before starting to update the record.
record_exprs(Us, St) ->
record_exprs(Us, St, [], []).
record_exprs([{record_field,Lf,{atom,_La,_F}=Name,Val}=Field0 | Us], St0, Pre, Fs) ->
case is_simple_val(Val) of
true ->
record_exprs(Us, St0, Pre, [Field0 | Fs]);
false ->
{Var,St} = new_var(Lf, St0),
Bind = {match,Lf,Var,Val},
Field = {record_field,Lf,Name,Var},
record_exprs(Us, St, [Bind | Pre], [Field | Fs])
end;
record_exprs([], St, Pre, Fs) ->
{reverse(Pre),Fs,St}.
is_simple_val({var,_,_}) -> true;
is_simple_val(Val) ->
try
erl_parse:normalise(Val),
true
catch error:_ ->
false
end.
%% pattern_bin([Element], State) -> {[Element],[Variable],[UsedVar],State}.
pattern_bin(Es0, St) ->
foldr(fun (E, Acc) -> pattern_element(E, Acc) end, {[],St}, Es0).
pattern_element({bin_element,Line,Expr0,Size,Type}, {Es,St0}) ->
{Expr,St1} = pattern(Expr0, St0),
{[{bin_element,Line,Expr,Size,Type} | Es],St1}.
%% expr_bin([Element], State) -> {[Element],State}.
expr_bin(Es0, St) ->
foldr(fun (E, Acc) -> bin_element(E, Acc) end, {[],St}, Es0).
bin_element({bin_element,Line,Expr,Size,Type}, {Es,St0}) ->
{Expr1,St1} = expr(Expr, St0),
{Size1,St2} = if Size =:= default -> {default,St1};
true -> expr(Size, St1)
end,
{[{bin_element,Line,Expr1,Size1,Type} | Es],St2}.
new_var(L, St0) ->
{New,St1} = new_var_name(St0),
{{var,L,New},St1}.
new_var_name(St) ->
C = St#exprec.vcount,
{list_to_atom("rec" ++ integer_to_list(C)),St#exprec{vcount=C+1}}.
make_list(Ts, Line) ->
foldr(fun (H, T) -> {cons,Line,H,T} end, {nil,Line}, Ts).
call_error(L, R) ->
{call,L,{remote,L,{atom,L,erlang},{atom,L,error}},[R]}.
import({Mod,Fs}, St) ->
St#exprec{imports=add_imports(Mod, Fs, St#exprec.imports)};
import(_Mod0, St) ->
St.
add_imports(Mod, [F | Fs], Is) ->
add_imports(Mod, Fs, orddict:store(F, Mod, Is));
add_imports(_, [], Is) -> Is.
imported(F, A, St) ->
case orddict:find({F,A}, St#exprec.imports) of
{ok,Mod} -> {yes,Mod};
error -> no
end.
%%%
%%% Replace is_record/3 in guards with matching if possible.
%%%
optimize_is_record(H0, G0, #exprec{compile=Opts}) ->
case opt_rec_vars(G0) of
[] ->
{H0,G0};
Rs0 ->
case lists:member(no_is_record_optimization, Opts) of
true ->
{H0,G0};
false ->
{H,Rs} = opt_pattern_list(H0, Rs0),
G = opt_remove(G0, Rs),
{H,G}
end
end.
%% opt_rec_vars(Guards) -> Vars.
%% Search through the guard expression, looking for
%% variables referenced in those is_record/3 calls that
%% will fail the entire guard if they evaluate to 'false'
%%
%% In the following code
%%
%% f(X, Y, Z) when is_record(X, r1) andalso
%% (is_record(Y, r2) orelse is_record(Z, r3))
%%
%% the entire guard will be false if the record test for
%% X fails, and the clause can be rewritten to:
%%
%% f({r1,...}=X, Y, Z) when true andalso
%% (is_record(Y, r2) or is_record(Z, r3))
%%
opt_rec_vars([G|Gs]) ->
Rs = opt_rec_vars_1(G, orddict:new()),
opt_rec_vars(Gs, Rs);
opt_rec_vars([]) -> orddict:new().
opt_rec_vars([G|Gs], Rs0) ->
Rs1 = opt_rec_vars_1(G, orddict:new()),
Rs = ordsets:intersection(Rs0, Rs1),
opt_rec_vars(Gs, Rs);
opt_rec_vars([], Rs) -> Rs.
opt_rec_vars_1([T|Ts], Rs0) ->
Rs = opt_rec_vars_2(T, Rs0),
opt_rec_vars_1(Ts, Rs);
opt_rec_vars_1([], Rs) -> Rs.
opt_rec_vars_2({op,_,'and',A1,A2}, Rs) ->
opt_rec_vars_1([A1,A2], Rs);
opt_rec_vars_2({op,_,'andalso',A1,A2}, Rs) ->
opt_rec_vars_1([A1,A2], Rs);
opt_rec_vars_2({op,_,'orelse',Arg,{atom,_,fail}}, Rs) ->
%% Since the second argument guarantees failure,
%% it is safe to inspect the first argument.
opt_rec_vars_2(Arg, Rs);
opt_rec_vars_2({call,_,{remote,_,{atom,_,erlang},{atom,_,is_record}},
[{var,_,V},{atom,_,Tag},{integer,_,Sz}]}, Rs) ->
orddict:store(V, {Tag,Sz}, Rs);
opt_rec_vars_2({call,_,{atom,_,is_record},
[{var,_,V},{atom,_,Tag},{integer,_,Sz}]}, Rs) ->
orddict:store(V, {Tag,Sz}, Rs);
opt_rec_vars_2(_, Rs) -> Rs.
opt_pattern_list(Ps, Rs) ->
opt_pattern_list(Ps, Rs, []).
opt_pattern_list([P0|Ps], Rs0, Acc) ->
{P,Rs} = opt_pattern(P0, Rs0),
opt_pattern_list(Ps, Rs, [P|Acc]);
opt_pattern_list([], Rs, Acc) ->
{reverse(Acc),Rs}.
opt_pattern({var,_,V}=Var, Rs0) ->
case orddict:find(V, Rs0) of
{ok,{Tag,Sz}} ->
Rs = orddict:store(V, {remove,Tag,Sz}, Rs0),
{opt_var(Var, Tag, Sz),Rs};
_ ->
{Var,Rs0}
end;
opt_pattern({cons,Line,H0,T0}, Rs0) ->
{H,Rs1} = opt_pattern(H0, Rs0),
{T,Rs} = opt_pattern(T0, Rs1),
{{cons,Line,H,T},Rs};
opt_pattern({tuple,Line,Es0}, Rs0) ->
{Es,Rs} = opt_pattern_list(Es0, Rs0),
{{tuple,Line,Es},Rs};
opt_pattern({match,Line,Pa0,Pb0}, Rs0) ->
{Pa,Rs1} = opt_pattern(Pa0, Rs0),
{Pb,Rs} = opt_pattern(Pb0, Rs1),
{{match,Line,Pa,Pb},Rs};
opt_pattern(P, Rs) -> {P,Rs}.
opt_var({var,Line,_}=Var, Tag, Sz) ->
Rp = record_pattern(2, -1, ignore, Sz, Line, [{atom,Line,Tag}]),
{match,Line,{tuple,Line,Rp},Var}.
opt_remove(Gs, Rs) ->
[opt_remove_1(G, Rs) || G <- Gs].
opt_remove_1(Ts, Rs) ->
[opt_remove_2(T, Rs) || T <- Ts].
opt_remove_2({op,L,'and'=Op,A1,A2}, Rs) ->
{op,L,Op,opt_remove_2(A1, Rs),opt_remove_2(A2, Rs)};
opt_remove_2({op,L,'andalso'=Op,A1,A2}, Rs) ->
{op,L,Op,opt_remove_2(A1, Rs),opt_remove_2(A2, Rs)};
opt_remove_2({op,L,'orelse',A1,A2}, Rs) ->
{op,L,'orelse',opt_remove_2(A1, Rs),A2};
opt_remove_2({call,Line,{remote,_,{atom,_,erlang},{atom,_,is_record}},
[{var,_,V},{atom,_,Tag},{integer,_,Sz}]}=A, Rs) ->
case orddict:find(V, Rs) of
{ok,{remove,Tag,Sz}} ->
{atom,Line,true};
_ ->
A
end;
opt_remove_2({call,Line,{atom,_,is_record},
[{var,_,V},{atom,_,Tag},{integer,_,Sz}]}=A, Rs) ->
case orddict:find(V, Rs) of
{ok,{remove,Tag,Sz}} ->
{atom,Line,true};
_ ->
A
end;
opt_remove_2(A, _) -> A.
neg_line(L) ->
erl_parse:set_line(L, fun(Line) -> -abs(Line) end).
