diff options
Diffstat (limited to 'lib/compiler/src/beam_types.erl')
| -rw-r--r-- | lib/compiler/src/beam_types.erl | 411 |
1 files changed, 411 insertions, 0 deletions
diff --git a/lib/compiler/src/beam_types.erl b/lib/compiler/src/beam_types.erl new file mode 100644 index 0000000000..07d3c3d3f2 --- /dev/null +++ b/lib/compiler/src/beam_types.erl @@ -0,0 +1,411 @@ +%% +%% %CopyrightBegin% +%% +%% Copyright Ericsson AB 2019. 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(beam_types). + +-include("beam_types.hrl"). + +-import(lists, [foldl/3]). + +-export([meet/1, meet/2, join/1, join/2, subtract/2]). + +-export([get_singleton_value/1, + get_tuple_size/1, + is_singleton_type/1, + is_boolean_type/1]). + +-export([get_element_type/2, set_element_type/3]). + +-export([make_type_from_value/1]). + +-export([make_atom/1, + make_boolean/0, + make_integer/1, + make_integer/2, + make_tuple/2, + make_tuple/3]). + +%% Return the "join" of Type1 and Type2. The join is a more general +%% type than Type1 and Type2. For example: +%% +%% join(#t_integer{elements=any}, #t_integer=elements={0,3}}) -> +%% #t_integer{} +%% +%% The join for two different types result in 'any', which is +%% the top element for our type lattice: +%% +%% join(#t_integer{}, #t_map{}) -> any + +-spec join(type(), type()) -> type(). + +join(T, T) -> + verified_type(T); +join(none, T) -> + verified_type(T); +join(T, none) -> + verified_type(T); +join(any, _) -> any; +join(_, any) -> any; +join(#t_atom{elements=[_|_]=Set1}, #t_atom{elements=[_|_]=Set2}) -> + Set = ordsets:union(Set1, Set2), + case ordsets:size(Set) of + Size when Size =< ?ATOM_SET_SIZE -> + #t_atom{elements=Set}; + _Size -> + #t_atom{elements=any} + end; +join(#t_atom{elements=any}=T, #t_atom{elements=[_|_]}) -> T; +join(#t_atom{elements=[_|_]}, #t_atom{elements=any}=T) -> T; +join(#t_bitstring{unit=U1}, #t_bitstring{unit=U2}) -> + #t_bitstring{unit=gcd(U1, U2)}; +join(#t_fun{}, #t_fun{}) -> + #t_fun{}; +join(#t_integer{elements={MinA,MaxA}}, + #t_integer{elements={MinB,MaxB}}) -> + #t_integer{elements={min(MinA,MinB),max(MaxA,MaxB)}}; +join(#t_bs_context{slots=SlotsA,valid=ValidA}, + #t_bs_context{slots=SlotsB,valid=ValidB}) -> + #t_bs_context{slots=min(SlotsA, SlotsB), + valid=ValidA band ValidB}; +join(#t_integer{}, #t_integer{}) -> #t_integer{}; +join(list, cons) -> list; +join(cons, list) -> list; +join(nil, cons) -> list; +join(cons, nil) -> list; +join(nil, list) -> list; +join(list, nil) -> list; +join(#t_integer{}, float) -> number; +join(float, #t_integer{}) -> number; +join(#t_integer{}, number) -> number; +join(number, #t_integer{}) -> number; +join(float, number) -> number; +join(number, float) -> number; +join(#t_tuple{size=Sz,exact=ExactA,elements=EsA}, + #t_tuple{size=Sz,exact=ExactB,elements=EsB}) -> + Exact = ExactA and ExactB, + Es = join_tuple_elements(Sz, EsA, EsB), + #t_tuple{size=Sz,exact=Exact,elements=Es}; +join(#t_tuple{size=SzA,elements=EsA}, #t_tuple{size=SzB,elements=EsB}) -> + Sz = min(SzA, SzB), + Es = join_tuple_elements(Sz, EsA, EsB), + #t_tuple{size=Sz,elements=Es}; +join(_T1, _T2) -> + %%io:format("~p ~p\n", [_T1,_T2]), + any. + +join_tuple_elements(MinSize, EsA, EsB) -> + Es0 = join_elements(EsA, EsB), + maps:filter(fun(Index, _Type) -> Index =< MinSize end, Es0). + +join_elements(Es1, Es2) -> + Keys = if + map_size(Es1) =< map_size(Es2) -> maps:keys(Es1); + map_size(Es1) > map_size(Es2) -> maps:keys(Es2) + end, + join_elements_1(Keys, Es1, Es2, #{}). + +join_elements_1([Key | Keys], Es1, Es2, Acc0) -> + case {Es1, Es2} of + {#{ Key := Type1 }, #{ Key := Type2 }} -> + Acc = set_element_type(Key, join(Type1, Type2), Acc0), + join_elements_1(Keys, Es1, Es2, Acc); + {#{}, #{}} -> + join_elements_1(Keys, Es1, Es2, Acc0) + end; +join_elements_1([], _Es1, _Es2, Acc) -> + Acc. + +gcd(A, B) -> + case A rem B of + 0 -> B; + X -> gcd(B, X) + end. + +%% Joins all the given types into a single type. +-spec join([type()]) -> type(). + +join([T1,T2|Ts]) -> + join([join(T1, T2)|Ts]); +join([T]) -> T. + +%% Return the "meet" of Type1 and Type2. The meet is a narrower +%% type than Type1 and Type2. For example: +%% +%% meet(#t_integer{elements=any}, #t_integer{elements={0,3}}) -> +%% #t_integer{elements={0,3}} +%% +%% The meet for two different types result in 'none', which is +%% the bottom element for our type lattice: +%% +%% meet(#t_integer{}, #t_map{}) -> none + +-spec meet(type(), type()) -> type(). + +meet(T, T) -> + verified_type(T); +meet(#t_atom{elements=[_|_]=Set1}, #t_atom{elements=[_|_]=Set2}) -> + case ordsets:intersection(Set1, Set2) of + [] -> + none; + [_|_]=Set -> + #t_atom{elements=Set} + end; +meet(#t_atom{elements=[_|_]}=T, #t_atom{elements=any}) -> + T; +meet(#t_atom{elements=any}, #t_atom{elements=[_|_]}=T) -> + T; +meet(#t_fun{arity=any}, #t_fun{}=T) -> + T; +meet(#t_fun{}=T, #t_fun{arity=any}) -> + T; +meet(#t_integer{elements={_,_}}=T, #t_integer{elements=any}) -> + T; +meet(#t_integer{elements=any}, #t_integer{elements={_,_}}=T) -> + T; +meet(#t_integer{elements={MinA,MaxA}}, #t_integer{elements={MinB,MaxB}}) + when MinA >= MinB, MaxA =< MaxB; + MinB >= MinA, MaxB =< MaxA -> + #t_integer{elements={max(MinA, MinB),min(MaxA, MaxB)}}; +meet(#t_integer{}=T, number) -> T; +meet(float=T, number) -> T; +meet(number, #t_integer{}=T) -> T; +meet(number, float=T) -> T; +meet(list, cons) -> cons; +meet(list, nil) -> nil; +meet(cons, list) -> cons; +meet(nil, list) -> nil; +meet(#t_tuple{}=T1, #t_tuple{}=T2) -> + meet_tuples(T1, T2); +meet(#t_bitstring{unit=U1}, #t_bitstring{unit=U2}) -> + #t_bitstring{unit=U1 * U2 div gcd(U1, U2)}; +meet(any, T) -> + verified_type(T); +meet(T, any) -> + verified_type(T); +meet(_, _) -> + %% Inconsistent types. There will be an exception at runtime. + none. + +meet_tuples(#t_tuple{size=Sz1,exact=true}, + #t_tuple{size=Sz2,exact=true}) when Sz1 =/= Sz2 -> + none; +meet_tuples(#t_tuple{size=Sz1,exact=Ex1,elements=Es1}, + #t_tuple{size=Sz2,exact=Ex2,elements=Es2}) -> + Size = max(Sz1, Sz2), + Exact = Ex1 or Ex2, + case meet_elements(Es1, Es2) of + none -> + none; + Es -> + #t_tuple{size=Size,exact=Exact,elements=Es} + end. + +meet_elements(Es1, Es2) -> + Keys = maps:keys(Es1) ++ maps:keys(Es2), + meet_elements_1(Keys, Es1, Es2, #{}). + +meet_elements_1([Key | Keys], Es1, Es2, Acc) -> + case {Es1, Es2} of + {#{ Key := Type1 }, #{ Key := Type2 }} -> + case meet(Type1, Type2) of + none -> none; + Type -> meet_elements_1(Keys, Es1, Es2, Acc#{ Key => Type }) + end; + {#{ Key := Type1 }, _} -> + meet_elements_1(Keys, Es1, Es2, Acc#{ Key => Type1 }); + {_, #{ Key := Type2 }} -> + meet_elements_1(Keys, Es1, Es2, Acc#{ Key => Type2 }) + end; +meet_elements_1([], _Es1, _Es2, Acc) -> + Acc. + +%% Meets all the given types into a single type. +-spec meet([type()]) -> type(). + +meet([T1,T2|Ts]) -> + meet([meet(T1, T2)|Ts]); +meet([T]) -> T. + +%% Subtract Type2 from Type1. Example: +%% subtract(list, cons) -> nil + +-spec subtract(type(), type()) -> type(). + +subtract(#t_atom{elements=[_|_]=Set0}, #t_atom{elements=[_|_]=Set1}) -> + case ordsets:subtract(Set0, Set1) of + [] -> none; + [_|_]=Set -> #t_atom{elements=Set} + end; +subtract(number, float) -> #t_integer{}; +subtract(number, #t_integer{elements=any}) -> float; +subtract(list, cons) -> nil; +subtract(list, nil) -> cons; +subtract(T, _) -> T. + +%% Verifies that the given type is well-formed. + +-spec verified_type(T) -> T when + T :: type(). + +verified_type(any=T) -> T; +verified_type(none=T) -> T; +verified_type(#t_atom{elements=any}=T) -> T; +verified_type(#t_atom{elements=[_|_]}=T) -> T; +verified_type(#t_bitstring{unit=U}=T) when is_integer(U), U >= 1 -> T; +verified_type(#t_bs_context{}=T) -> T; +verified_type(#t_fun{arity=Arity}=T) when Arity =:= any; is_integer(Arity) -> T; +verified_type(#t_integer{elements=any}=T) -> T; +verified_type(#t_integer{elements={Min,Max}}=T) + when is_integer(Min), is_integer(Max), Min =< Max -> T; +verified_type(list=T) -> T; +verified_type(#t_map{}=T) -> T; +verified_type(nil=T) -> T; +verified_type(cons=T) -> T; +verified_type(number=T) -> T; +verified_type(#t_tuple{size=Size,elements=Es}=T) -> + %% All known elements must have a valid index and type. 'any' is prohibited + %% since it's implicit and should never be present in the map. + maps:fold(fun(Index, Element, _) when is_integer(Index), + 1 =< Index, Index =< Size, + Element =/= any, Element =/= none -> + verified_type(Element) + end, [], Es), + T; +verified_type(float=T) -> T. + +%%% +%%% Type operators +%%% + +-spec get_singleton_value(Type) -> Result when + Type :: type(), + Result :: {ok, term()} | error. +get_singleton_value(#t_atom{elements=[Atom]}) -> + {ok, Atom}; +get_singleton_value(#t_integer{elements={Int,Int}}) -> + {ok, Int}; +get_singleton_value(nil) -> + {ok, []}; +get_singleton_value(_) -> + error. + +-spec get_tuple_size(Type) -> Result when + Type :: type(), + Result :: none | {at_least, Size} | {exact, Size}, + Size :: non_neg_integer(). +get_tuple_size(#t_tuple{size=Size,exact=false}) -> + {at_least,Size}; +get_tuple_size(#t_tuple{size=Size,exact=true}) -> + {exact,Size}; +get_tuple_size(_) -> + none. + +-spec is_boolean_type(type()) -> boolean(). +is_boolean_type(#t_atom{elements=[F,T]}) -> + F =:= false andalso T =:= true; +is_boolean_type(#t_atom{elements=[B]}) -> + is_boolean(B); +is_boolean_type(_) -> false. + +-spec is_singleton_type(type()) -> boolean(). +is_singleton_type(Type) -> + get_singleton_value(Type) =/= error. + +-spec set_element_type(Key, Type, Elements) -> Elements when + Key :: term(), + Type :: type(), + Elements :: elements(). +set_element_type(_Key, none, Es) -> + Es; +set_element_type(Key, any, Es) -> + maps:remove(Key, Es); +set_element_type(Key, Type, Es) -> + Es#{ Key => Type }. + +-spec get_element_type(Key, Elements) -> type() when + Key :: term(), + Elements :: elements(). +get_element_type(Index, Es) -> + case Es of + #{ Index := T } -> T; + #{} -> any + end. + +%%% +%%% Type constructors +%%% + +-spec make_type_from_value(term()) -> type(). +make_type_from_value(Value) -> + mtfv_1(Value). + +mtfv_1([]) -> nil; +mtfv_1([_|_]) -> cons; +mtfv_1(A) when is_atom(A) -> #t_atom{elements=[A]}; +mtfv_1(B) when is_binary(B) -> #t_bitstring{unit=8}; +mtfv_1(B) when is_bitstring(B) -> #t_bitstring{}; +mtfv_1(F) when is_float(F) -> float; +mtfv_1(F) when is_function(F) -> + {arity, Arity} = erlang:fun_info(F, arity), + #t_fun{arity=Arity}; +mtfv_1(I) when is_integer(I) -> make_integer(I); +mtfv_1(M) when is_map(M) -> #t_map{}; +mtfv_1(T) when is_tuple(T) -> + {Es,_} = foldl(fun(Val, {Es0, Index}) -> + Type = mtfv_1(Val), + Es = set_element_type(Index, Type, Es0), + {Es, Index + 1} + end, {#{}, 1}, tuple_to_list(T)), + #t_tuple{exact=true,size=tuple_size(T),elements=Es}; +mtfv_1(_Term) -> + any. + +-spec make_atom(atom()) -> type(). +make_atom(Atom) when is_atom(Atom) -> + #t_atom{elements=[Atom]}. + +-spec make_boolean() -> type(). +make_boolean() -> + #t_atom{elements=[false,true]}. + +-spec make_integer(integer()) -> type(). +make_integer(Int) when is_integer(Int) -> + make_integer(Int, Int). + +-spec make_integer(Min, Max) -> type() when + Min :: integer(), + Max :: integer(). +make_integer(Min, Max) when is_integer(Min), is_integer(Max), Min =< Max -> + #t_integer{elements={Min,Max}}. + +-spec make_tuple(Size, Exact) -> type() when + Size :: non_neg_integer(), + Exact :: boolean(). +make_tuple(Size, Exact) -> + make_tuple(Size, Exact, #{}). + +-spec make_tuple(Size, Exact, Elements) -> type() when + Size :: non_neg_integer(), + Exact :: boolean(), + Elements :: #{ non_neg_integer() => type() }. +make_tuple(Size, Exact, Elements) -> + #t_tuple{size=Size, + exact=Exact, + elements=Elements}. |