diff options
Diffstat (limited to 'lib/compiler/src/beam_ssa_type.erl')
| -rw-r--r-- | lib/compiler/src/beam_ssa_type.erl | 89 |
1 files changed, 48 insertions, 41 deletions
diff --git a/lib/compiler/src/beam_ssa_type.erl b/lib/compiler/src/beam_ssa_type.erl index 06b42f1928..68920e7dd3 100644 --- a/lib/compiler/src/beam_ssa_type.erl +++ b/lib/compiler/src/beam_ssa_type.erl @@ -23,8 +23,8 @@ -include("beam_ssa_opt.hrl"). -import(lists, [all/2,any/2,droplast/1,foldl/3,last/1,member/2, - keyfind/3,partition/2,reverse/1,reverse/2, - seq/2,sort/1,split/2]). + keyfind/3,reverse/1,reverse/2, + sort/1,split/2]). -define(UNICODE_INT, #t_integer{elements={0,16#10FFFF}}). @@ -840,15 +840,8 @@ type({bif,Bif}, Args, Ts, _Ds) -> Type -> Type end; -type(bs_init, [#b_literal{val=Type}|Args], _Ts, _Ds) -> - case {Type,Args} of - {new,[_,#b_literal{val=Unit}]} -> - {binary,Unit}; - {append,[_,_,#b_literal{val=Unit}]} -> - {binary,Unit}; - {private_append,[_,_,#b_literal{val=Unit}]} -> - {binary,Unit} - end; +type(bs_init, _Args, _Ts, _Ds) -> + {binary, 1}; type(bs_extract, [Ctx], Ts, _Ds) -> #t_bs_match{type=Type} = get_type(Ctx, Ts), Type; @@ -874,11 +867,11 @@ type(call, [#b_remote{mod=#b_literal{val=Mod}, true -> none end; - {#t_integer{elements={Min,Max}}, + {#t_integer{elements={Min,_}}=IntType, #t_tuple{elements=Es0,size=Size}=T} -> - %% We know this will land between Min and Max, so kill the - %% types for those indexes. - Es = maps:without(seq(Min, Max), Es0), + %% Remove type information for all indices that + %% falls into the range of the integer. + Es = remove_element_info(IntType, Es0), case T#t_tuple.exact of false -> T#t_tuple{elements=Es,size=max(Min, Size)}; @@ -896,11 +889,15 @@ type(call, [#b_remote{mod=#b_literal{val=Mod}, {_,_} -> #t_tuple{} end; - {erlang,'++',[List1,List2]} -> - case get_type(List1, Ts) =:= cons orelse - get_type(List2, Ts) =:= cons of - true -> cons; - false -> list + {erlang,'++',[LHS,RHS]} -> + LType = get_type(LHS, Ts), + RType = get_type(RHS, Ts), + case LType =:= cons orelse RType =:= cons of + true -> + cons; + false -> + %% `[] ++ RHS` yields RHS, even if RHS is not a list. + join(list, RType) end; {erlang,'--',[_,_]} -> list; @@ -1388,24 +1385,11 @@ get_type(#b_literal{val=Val}, _Ts) -> %% type for L. For example, if L was known to be 'list', subtracting %% 'cons' would give 'nil' as the only possible type. The result of the %% subtraction for L will be added to FailTypes. -%% -%% Here is another example, asking about the variable Bool: -%% -%% Head = bif:hd L -%% Bool = succeeded Head -%% -%% 'succeeded Head' will evaluate to 'true' if the instrution that -%% defined Head succeeded. In this case, it is the 'bif:hd L' -%% instruction, which will succeed if L is 'cons'. Thus, the meet of -%% the previous type for L and 'cons' will be added to SuccTypes. -%% -%% If 'succeeded Head' evaluates to 'false', it means that 'bif:hd L' -%% failed and that L is not 'cons'. 'cons' can be subtracted from the -%% previously known type for L and the result put in FailTypes. infer_types_br(#b_var{}=V, Ts, #d{ds=Ds}) -> #{V:=#b_set{op=Op,args=Args}} = Ds, - Types0 = infer_type(Op, Args, Ds), + PosTypes0 = infer_type(Op, Args, Ds), + NegTypes0 = infer_type_negative(Op, Args, Ds), %% We must be careful with types inferred from '=:='. %% @@ -1416,13 +1400,17 @@ infer_types_br(#b_var{}=V, Ts, #d{ds=Ds}) -> %% %% However, it is safe to subtract a type inferred from '=:=' if %% it is single-valued, e.g. if it is [] or the atom 'true'. - EqTypes0 = infer_eq_type(Op, Args, Ts, Ds), - {Types1,EqTypes} = partition(fun({_,T}) -> - is_singleton_type(T) - end, EqTypes0), - Types = Types1 ++ Types0, - {meet_types(EqTypes++Types, Ts),subtract_types(Types, Ts)}. + EqTypes = infer_eq_type(Op, Args, Ts, Ds), + NegTypes1 = [P || {_,T}=P <- EqTypes, is_singleton_type(T)], + + PosTypes = EqTypes ++ PosTypes0, + SuccTs = meet_types(PosTypes, Ts), + + NegTypes = NegTypes0 ++ NegTypes1, + FailTs = subtract_types(NegTypes, Ts), + + {SuccTs,FailTs}. infer_types_switch(V, Lit, Ts, #d{ds=Ds}) -> Types = infer_eq_type({bif,'=:='}, [V, Lit], Ts, Ds), @@ -1457,6 +1445,19 @@ infer_eq_lit(#b_set{op=get_tuple_element, [{Tuple,#t_tuple{size=Index,elements=Es}}]; infer_eq_lit(_, _) -> []. +infer_type_negative(Op, Args, Ds) -> + case is_negative_inference_safe(Op, Args) of + true -> + infer_type(Op, Args, Ds); + false -> + [] + end. + +%% Conservative list of instructions for which negative +%% inference is safe. +is_negative_inference_safe(is_nonempty_list, _Args) -> true; +is_negative_inference_safe(_, _) -> false. + infer_type({bif,element}, [#b_literal{val=Pos},#b_var{}=Tuple], _Ds) -> if is_integer(Pos), 1 =< Pos -> @@ -1649,6 +1650,12 @@ get_literal_from_type(nil) -> #b_literal{val=[]}; get_literal_from_type(_) -> none. +remove_element_info(#t_integer{elements={Min,Max}}, Es) -> + foldl(fun(El, Acc) when Min =< El, El =< Max -> + maps:remove(El, Acc); + (_El, Acc) -> Acc + end, Es, maps:keys(Es)). + t_atom() -> #t_atom{elements=any}. |