diff options
Diffstat (limited to 'lib/compiler/src/sys_core_fold.erl')
| -rw-r--r-- | lib/compiler/src/sys_core_fold.erl | 1599 |
1 files changed, 812 insertions, 787 deletions
diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl index ed8f609082..65699ccda9 100644 --- a/lib/compiler/src/sys_core_fold.erl +++ b/lib/compiler/src/sys_core_fold.erl @@ -3,16 +3,17 @@ %% %% Copyright Ericsson AB 1999-2013. 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/. +%% 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 %% -%% 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. +%% 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% %% @@ -70,7 +71,8 @@ -export([module/2,format_error/1]). -import(lists, [map/2,foldl/3,foldr/3,mapfoldl/3,all/2,any/2, - reverse/1,reverse/2,member/2,nth/2,flatten/1,unzip/1]). + reverse/1,reverse/2,member/2,nth/2,flatten/1, + unzip/1,keyfind/3]). -import(cerl, [ann_c_cons/3,ann_c_map/3,ann_c_tuple/2]). @@ -91,10 +93,14 @@ -endif. %% Variable value info. --record(sub, {v=[], %Variable substitutions - s=[], %Variables in scope - t=[], %Types - in_guard=false}). %In guard or not. +-record(sub, {v=[], %Variable substitutions + s=cerl_sets:new() :: cerl_sets:set(), %Variables in scope + t=#{} :: map(), %Types + in_guard=false}). %In guard or not. + +-type type_info() :: cerl:cerl() | 'bool' | 'integer'. +-type yes_no_maybe() :: 'yes' | 'no' | 'maybe'. +-type sub() :: #sub{}. -spec module(cerl:c_module(), [compile:option()]) -> {'ok', cerl:c_module(), [_]}. @@ -293,7 +299,8 @@ expr(#c_seq{arg=Arg0,body=B0}=Seq0, Ctxt, Sub) -> false -> Seq0#c_seq{arg=Arg,body=B1} end end; -expr(#c_let{}=Let, Ctxt, Sub) -> +expr(#c_let{}=Let0, Ctxt, Sub) -> + Let = opt_case_in_let(Let0), case simplify_let(Let, Sub) of impossible -> %% The argument for the let is "simple", i.e. has no @@ -313,7 +320,7 @@ expr(#c_letrec{defs=Fs0,body=B0}=Letrec, Ctxt, Sub) -> Fs1 = map(fun ({Name,Fb}) -> {Name,expr(Fb, {letrec,Ctxt}, Sub)} end, Fs0), - B1 = body(B0, value, Sub), + B1 = body(B0, Ctxt, Sub), Letrec#c_letrec{defs=Fs1,body=B1}; expr(#c_case{}=Case0, Ctxt, Sub) -> %% Ideally, the compiler should only emit warnings when there is @@ -462,10 +469,7 @@ is_safe_simple(#c_call{module=#c_literal{val=erlang}, case erl_internal:bool_op(Name, NumArgs) of true -> %% Boolean operators are safe if the arguments are boolean. - all(fun(#c_var{name=V}) -> is_boolean_type(V, Sub); - (#c_literal{val=Lit}) -> is_boolean(Lit); - (_) -> false - end, Args); + all(fun(C) -> is_boolean_type(C, Sub) =:= yes end, Args); false -> %% We need a rather complicated test to ensure that %% we only allow safe calls that are allowed in a guard. @@ -607,14 +611,6 @@ eval_binary_1([#c_bitstr{val=#c_literal{val=Val},size=#c_literal{val=Sz}, error:_ -> throw(impossible) end; -eval_binary_1([#c_bitstr{val=#c_literal{},size=#c_literal{}, - unit=#c_literal{},type=#c_literal{}, - flags=#c_cons{}=Flags}=Bitstr|Ss], Acc0) -> - case cerl:fold_literal(Flags) of - #c_literal{} = Flags1 -> - eval_binary_1([Bitstr#c_bitstr{flags=Flags1}|Ss], Acc0); - _ -> throw(impossible) - end; eval_binary_1([], Acc) -> Acc; eval_binary_1(_, _) -> throw(impossible). @@ -688,23 +684,15 @@ count_bits_1(Int, Bits) -> count_bits_1(Int bsr 64, Bits+64). %% a rewritten expression consisting of a sequence of %% the arguments only is returned. -useless_call(effect, #c_call{anno=Anno, - module=#c_literal{val=Mod}, +useless_call(effect, #c_call{module=#c_literal{val=Mod}, name=#c_literal{val=Name}, args=Args}=Call) -> A = length(Args), case erl_bifs:is_safe(Mod, Name, A) of false -> case erl_bifs:is_pure(Mod, Name, A) of - true -> - case member(result_not_wanted, Anno) of - false -> - add_warning(Call, result_ignored); - true -> - ok - end; - false -> - ok + true -> add_warning(Call, result_ignored); + false -> ok end, no; true -> @@ -730,385 +718,23 @@ make_effect_seq([], _) -> void(). call(#c_call{args=As}=Call, #c_literal{val=M}=M0, #c_literal{val=N}=N0, Sub) -> case get(no_inline_list_funcs) of true -> - call_0(Call, M0, N0, As, Sub); + call_1(Call, M0, N0, As, Sub); false -> - call_1(Call, M, N, As, Sub) + case sys_core_fold_lists:call(Call, M, N, As) of + none -> + call_1(Call, M, N, As, Sub); + Core -> + expr(Core, Sub) + end + end; call(#c_call{args=As}=Call, M, N, Sub) -> - call_0(Call, M, N, As, Sub). + call_1(Call, M, N, As, Sub). -call_0(Call, M, N, As0, Sub) -> +call_1(Call, M, N, As0, Sub) -> As1 = expr_list(As0, value, Sub), fold_call(Call#c_call{args=As1}, M, N, As1, Sub). -%% We inline some very common higher order list operations. -%% We use the same evaluation order as the library function. - -call_1(#c_call{anno=Anno}, lists, all, [Arg1,Arg2], Sub) -> - Loop = #c_var{name={'lists^all',1}}, - F = #c_var{name='F'}, - Xs = #c_var{name='Xs'}, - X = #c_var{name='X'}, - Err1 = #c_tuple{es=[#c_literal{val='case_clause'}, X]}, - CC1 = #c_clause{pats=[#c_literal{val=true}], guard=#c_literal{val=true}, - body=#c_apply{anno=Anno, op=Loop, args=[Xs]}}, - CC2 = #c_clause{pats=[#c_literal{val=false}], guard=#c_literal{val=true}, - body=#c_literal{val=false}}, - CC3 = #c_clause{pats=[X], guard=#c_literal{val=true}, - body=match_fail(Anno, Err1)}, - C1 = #c_clause{pats=[#c_cons{hd=X, tl=Xs}], guard=#c_literal{val=true}, - body=#c_case{arg=#c_apply{anno=Anno, op=F, args=[X]}, - clauses = [CC1, CC2, CC3]}}, - C2 = #c_clause{pats=[#c_literal{val=[]}], - guard=#c_call{module=#c_literal{val=erlang}, - name=#c_literal{val=is_function}, - args=[F, #c_literal{val=1}]}, - body=#c_literal{val=true}}, - Err2 = #c_tuple{es=[#c_literal{val='function_clause'}, F, Xs]}, - C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=match_fail([{function_name,{'lists^all',1}}|Anno], Err2)}, - Fun = #c_fun{vars=[Xs], - body=#c_case{arg=Xs, clauses=[C1, C2, C3]}}, - L = #c_var{name='L'}, - expr(#c_let{vars=[F, L], arg=#c_values{es=[Arg1, Arg2]}, - body=#c_letrec{defs=[{Loop,Fun}], - body=#c_apply{anno=Anno, op=Loop, args=[L]}}}, - Sub); -call_1(#c_call{anno=Anno}, lists, any, [Arg1,Arg2], Sub) -> - Loop = #c_var{name={'lists^any',1}}, - F = #c_var{name='F'}, - Xs = #c_var{name='Xs'}, - X = #c_var{name='X'}, - Err1 = #c_tuple{es=[#c_literal{val='case_clause'}, X]}, - CC1 = #c_clause{pats=[#c_literal{val=true}], guard=#c_literal{val=true}, - body=#c_literal{val=true}}, - CC2 = #c_clause{pats=[#c_literal{val=false}], guard=#c_literal{val=true}, - body=#c_apply{anno=Anno, op=Loop, args=[Xs]}}, - CC3 = #c_clause{pats=[X], guard=#c_literal{val=true}, - body=match_fail(Anno, Err1)}, - C1 = #c_clause{pats=[#c_cons{hd=X, tl=Xs}], guard=#c_literal{val=true}, - body=#c_case{arg=#c_apply{anno=Anno, op=F, args=[X]}, - clauses = [CC1, CC2, CC3]}}, - C2 = #c_clause{pats=[#c_literal{val=[]}], - guard=#c_call{module=#c_literal{val=erlang}, - name=#c_literal{val=is_function}, - args=[F, #c_literal{val=1}]}, - body=#c_literal{val=false}}, - Err2 = #c_tuple{es=[#c_literal{val='function_clause'}, F, Xs]}, - C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=match_fail([{function_name,{'lists^any',1}}|Anno], Err2)}, - Fun = #c_fun{vars=[Xs], - body=#c_case{arg=Xs, clauses=[C1, C2, C3]}}, - L = #c_var{name='L'}, - expr(#c_let{vars=[F, L], arg=#c_values{es=[Arg1, Arg2]}, - body=#c_letrec{defs=[{Loop,Fun}], - body=#c_apply{anno=Anno, op=Loop, args=[L]}}}, - Sub); -call_1(#c_call{anno=Anno}, lists, foreach, [Arg1,Arg2], Sub) -> - Loop = #c_var{name={'lists^foreach',1}}, - F = #c_var{name='F'}, - Xs = #c_var{name='Xs'}, - X = #c_var{name='X'}, - C1 = #c_clause{pats=[#c_cons{hd=X, tl=Xs}], guard=#c_literal{val=true}, - body=#c_seq{arg=#c_apply{anno=Anno, op=F, args=[X]}, - body=#c_apply{anno=Anno, op=Loop, args=[Xs]}}}, - C2 = #c_clause{pats=[#c_literal{val=[]}], - guard=#c_call{module=#c_literal{val=erlang}, - name=#c_literal{val=is_function}, - args=[F, #c_literal{val=1}]}, - body=#c_literal{val=ok}}, - Err = #c_tuple{es=[#c_literal{val='function_clause'}, F, Xs]}, - C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=match_fail([{function_name,{'lists^foreach',1}}|Anno], Err)}, - Fun = #c_fun{vars=[Xs], - body=#c_case{arg=Xs, clauses=[C1, C2, C3]}}, - L = #c_var{name='L'}, - expr(#c_let{vars=[F, L], arg=#c_values{es=[Arg1, Arg2]}, - body=#c_letrec{defs=[{Loop,Fun}], - body=#c_apply{anno=Anno, op=Loop, args=[L]}}}, - Sub); -call_1(#c_call{anno=Anno}, lists, map, [Arg1,Arg2], Sub) -> - Loop = #c_var{name={'lists^map',1}}, - F = #c_var{name='F'}, - Xs = #c_var{name='Xs'}, - X = #c_var{name='X'}, - H = #c_var{name='H'}, - C1 = #c_clause{pats=[#c_cons{hd=X, tl=Xs}], guard=#c_literal{val=true}, - body=#c_let{vars=[H], arg=#c_apply{anno=Anno, - op=F, - args=[X]}, - body=#c_cons{hd=H, - anno=[compiler_generated], - tl=#c_apply{anno=Anno, - op=Loop, - args=[Xs]}}}}, - C2 = #c_clause{pats=[#c_literal{val=[]}], - guard=#c_call{module=#c_literal{val=erlang}, - name=#c_literal{val=is_function}, - args=[F, #c_literal{val=1}]}, - body=#c_literal{val=[]}}, - Err = #c_tuple{es=[#c_literal{val='function_clause'}, F, Xs]}, - C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=match_fail([{function_name,{'lists^map',1}}|Anno], Err)}, - Fun = #c_fun{vars=[Xs], - body=#c_case{arg=Xs, clauses=[C1, C2, C3]}}, - L = #c_var{name='L'}, - expr(#c_let{vars=[F, L], arg=#c_values{es=[Arg1, Arg2]}, - body=#c_letrec{defs=[{Loop,Fun}], - body=#c_apply{anno=Anno, op=Loop, args=[L]}}}, - Sub); -call_1(#c_call{anno=Anno}, lists, flatmap, [Arg1,Arg2], Sub) -> - Loop = #c_var{name={'lists^flatmap',1}}, - F = #c_var{name='F'}, - Xs = #c_var{name='Xs'}, - X = #c_var{name='X'}, - H = #c_var{name='H'}, - C1 = #c_clause{pats=[#c_cons{hd=X, tl=Xs}], guard=#c_literal{val=true}, - body=#c_let{vars=[H], - arg=#c_apply{anno=Anno, op=F, args=[X]}, - body=#c_call{anno=[compiler_generated|Anno], - module=#c_literal{val=erlang}, - name=#c_literal{val='++'}, - args=[H, - #c_apply{anno=Anno, - op=Loop, - args=[Xs]}]}}}, - C2 = #c_clause{pats=[#c_literal{val=[]}], - guard=#c_call{module=#c_literal{val=erlang}, - name=#c_literal{val=is_function}, - args=[F, #c_literal{val=1}]}, - body=#c_literal{val=[]}}, - Err = #c_tuple{es=[#c_literal{val='function_clause'}, F, Xs]}, - C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=match_fail([{function_name,{'lists^flatmap',1}}|Anno], Err)}, - Fun = #c_fun{vars=[Xs], - body=#c_case{arg=Xs, clauses=[C1, C2, C3]}}, - L = #c_var{name='L'}, - expr(#c_let{vars=[F, L], arg=#c_values{es=[Arg1, Arg2]}, - body=#c_letrec{defs=[{Loop,Fun}], - body=#c_apply{anno=Anno, op=Loop, args=[L]}}}, - Sub); -call_1(#c_call{anno=Anno}, lists, filter, [Arg1,Arg2], Sub) -> - Loop = #c_var{name={'lists^filter',1}}, - F = #c_var{name='F'}, - Xs = #c_var{name='Xs'}, - X = #c_var{name='X'}, - B = #c_var{name='B'}, - Err1 = #c_tuple{es=[#c_literal{val='case_clause'}, X]}, - CC1 = #c_clause{pats=[#c_literal{val=true}], guard=#c_literal{val=true}, - body=#c_cons{anno=[compiler_generated], hd=X, tl=Xs}}, - CC2 = #c_clause{pats=[#c_literal{val=false}], guard=#c_literal{val=true}, - body=Xs}, - CC3 = #c_clause{pats=[X], guard=#c_literal{val=true}, - body=match_fail(Anno, Err1)}, - Case = #c_case{arg=B, clauses = [CC1, CC2, CC3]}, - C1 = #c_clause{pats=[#c_cons{hd=X, tl=Xs}], guard=#c_literal{val=true}, - body=#c_let{vars=[B], - arg=#c_apply{anno=Anno, op=F, args=[X]}, - body=#c_let{vars=[Xs], - arg=#c_apply{anno=Anno, - op=Loop, - args=[Xs]}, - body=Case}}}, - C2 = #c_clause{pats=[#c_literal{val=[]}], - guard=#c_call{module=#c_literal{val=erlang}, - name=#c_literal{val=is_function}, - args=[F, #c_literal{val=1}]}, - body=#c_literal{val=[]}}, - Err2 = #c_tuple{es=[#c_literal{val='function_clause'}, F, Xs]}, - C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=match_fail([{function_name,{'lists^filter',1}}|Anno], Err2)}, - Fun = #c_fun{vars=[Xs], - body=#c_case{arg=Xs, clauses=[C1, C2, C3]}}, - L = #c_var{name='L'}, - expr(#c_let{vars=[F, L], arg=#c_values{es=[Arg1, Arg2]}, - body=#c_letrec{defs=[{Loop,Fun}], - body=#c_apply{anno=Anno, op=Loop, args=[L]}}}, - Sub); -call_1(#c_call{anno=Anno}, lists, foldl, [Arg1,Arg2,Arg3], Sub) -> - Loop = #c_var{name={'lists^foldl',2}}, - F = #c_var{name='F'}, - Xs = #c_var{name='Xs'}, - X = #c_var{name='X'}, - A = #c_var{name='A'}, - C1 = #c_clause{pats=[#c_cons{hd=X, tl=Xs}], guard=#c_literal{val=true}, - body=#c_apply{anno=Anno, - op=Loop, - args=[Xs, #c_apply{anno=Anno, - op=F, - args=[X, A]}]}}, - C2 = #c_clause{pats=[#c_literal{val=[]}], - guard=#c_call{module=#c_literal{val=erlang}, - name=#c_literal{val=is_function}, - args=[F, #c_literal{val=2}]}, - body=A}, - Err = #c_tuple{es=[#c_literal{val='function_clause'}, F, A, Xs]}, - C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=match_fail([{function_name,{'lists^foldl',2}}|Anno], Err)}, - Fun = #c_fun{vars=[Xs, A], - body=#c_case{arg=Xs, clauses=[C1, C2, C3]}}, - L = #c_var{name='L'}, - expr(#c_let{vars=[F, A, L], arg=#c_values{es=[Arg1, Arg2, Arg3]}, - body=#c_letrec{defs=[{Loop,Fun}], - body=#c_apply{anno=Anno, op=Loop, args=[L, A]}}}, - Sub); -call_1(#c_call{anno=Anno}, lists, foldr, [Arg1,Arg2,Arg3], Sub) -> - Loop = #c_var{name={'lists^foldr',2}}, - F = #c_var{name='F'}, - Xs = #c_var{name='Xs'}, - X = #c_var{name='X'}, - A = #c_var{name='A'}, - C1 = #c_clause{pats=[#c_cons{hd=X, tl=Xs}], guard=#c_literal{val=true}, - body=#c_apply{anno=Anno, - op=F, - args=[X, #c_apply{anno=Anno, - op=Loop, - args=[Xs, A]}]}}, - C2 = #c_clause{pats=[#c_literal{val=[]}], - guard=#c_call{module=#c_literal{val=erlang}, - name=#c_literal{val=is_function}, - args=[F, #c_literal{val=2}]}, - body=A}, - Err = #c_tuple{es=[#c_literal{val='function_clause'}, F, A, Xs]}, - C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=match_fail([{function_name,{'lists^foldr',2}}|Anno], Err)}, - Fun = #c_fun{vars=[Xs, A], - body=#c_case{arg=Xs, clauses=[C1, C2, C3]}}, - L = #c_var{name='L'}, - expr(#c_let{vars=[F, A, L], arg=#c_values{es=[Arg1, Arg2, Arg3]}, - body=#c_letrec{defs=[{Loop,Fun}], - body=#c_apply{anno=Anno, op=Loop, args=[L, A]}}}, - Sub); -call_1(#c_call{anno=Anno}, lists, mapfoldl, [Arg1,Arg2,Arg3], Sub) -> - Loop = #c_var{name={'lists^mapfoldl',2}}, - F = #c_var{name='F'}, - Xs = #c_var{name='Xs'}, - X = #c_var{name='X'}, - Avar = #c_var{name='A'}, - Match = - fun (A, P, E) -> - C1 = #c_clause{pats=[P], guard=#c_literal{val=true}, body=E}, - Err = #c_tuple{es=[#c_literal{val='badmatch'}, X]}, - C2 = #c_clause{pats=[X], guard=#c_literal{val=true}, - body=match_fail(Anno, Err)}, - #c_case{arg=A, clauses=[C1, C2]} - end, - C1 = #c_clause{pats=[#c_cons{hd=X, tl=Xs}], guard=#c_literal{val=true}, - body=Match(#c_apply{anno=Anno, op=F, args=[X, Avar]}, - #c_tuple{es=[X, Avar]}, -%%% Tuple passing version - Match(#c_apply{anno=Anno, - op=Loop, - args=[Xs, Avar]}, - #c_tuple{es=[Xs, Avar]}, - #c_tuple{anno=[compiler_generated], - es=[#c_cons{anno=[compiler_generated], - hd=X, tl=Xs}, - Avar]}) -%%% Multiple-value version -%%% #c_let{vars=[Xs,A], -%%% %% The tuple here will be optimised -%%% %% away later; no worries. -%%% arg=#c_apply{op=Loop, args=[Xs, A]}, -%%% body=#c_values{es=[#c_cons{hd=X, tl=Xs}, -%%% A]}} - )}, - C2 = #c_clause{pats=[#c_literal{val=[]}], - guard=#c_call{module=#c_literal{val=erlang}, - name=#c_literal{val=is_function}, - args=[F, #c_literal{val=2}]}, -%%% Tuple passing version - body=#c_tuple{anno=[compiler_generated], - es=[#c_literal{val=[]}, Avar]}}, -%%% Multiple-value version -%%% body=#c_values{es=[#c_literal{val=[]}, A]}}, - Err = #c_tuple{es=[#c_literal{val='function_clause'}, F, Avar, Xs]}, - C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=match_fail([{function_name,{'lists^mapfoldl',2}}|Anno], Err)}, - Fun = #c_fun{vars=[Xs, Avar], - body=#c_case{arg=Xs, clauses=[C1, C2, C3]}}, - L = #c_var{name='L'}, - expr(#c_let{vars=[F, Avar, L], arg=#c_values{es=[Arg1, Arg2, Arg3]}, - body=#c_letrec{defs=[{Loop,Fun}], -%%% Tuple passing version - body=#c_apply{anno=Anno, - op=Loop, - args=[L, Avar]}}}, -%%% Multiple-value version -%%% body=#c_let{vars=[Xs, A], -%%% arg=#c_apply{op=Loop, -%%% args=[L, A]}, -%%% body=#c_tuple{es=[Xs, A]}}}}, - Sub); -call_1(#c_call{anno=Anno}, lists, mapfoldr, [Arg1,Arg2,Arg3], Sub) -> - Loop = #c_var{name={'lists^mapfoldr',2}}, - F = #c_var{name='F'}, - Xs = #c_var{name='Xs'}, - X = #c_var{name='X'}, - Avar = #c_var{name='A'}, - Match = - fun (A, P, E) -> - C1 = #c_clause{pats=[P], guard=#c_literal{val=true}, body=E}, - Err = #c_tuple{es=[#c_literal{val='badmatch'}, X]}, - C2 = #c_clause{pats=[X], guard=#c_literal{val=true}, - body=match_fail(Anno, Err)}, - #c_case{arg=A, clauses=[C1, C2]} - end, - C1 = #c_clause{pats=[#c_cons{hd=X, tl=Xs}], guard=#c_literal{val=true}, -%%% Tuple passing version - body=Match(#c_apply{anno=Anno, - op=Loop, - args=[Xs, Avar]}, - #c_tuple{es=[Xs, Avar]}, - Match(#c_apply{anno=Anno, op=F, args=[X, Avar]}, - #c_tuple{es=[X, Avar]}, - #c_tuple{anno=[compiler_generated], - es=[#c_cons{anno=[compiler_generated], - hd=X, tl=Xs}, Avar]})) -%%% Multiple-value version -%%% body=#c_let{vars=[Xs,A], -%%% %% The tuple will be optimised away -%%% arg=#c_apply{op=Loop, args=[Xs, A]}, -%%% body=Match(#c_apply{op=F, args=[X, A]}, -%%% #c_tuple{es=[X, A]}, -%%% #c_values{es=[#c_cons{hd=X, tl=Xs}, -%%% A]})} - }, - C2 = #c_clause{pats=[#c_literal{val=[]}], - guard=#c_call{module=#c_literal{val=erlang}, - name=#c_literal{val=is_function}, - args=[F, #c_literal{val=2}]}, -%%% Tuple passing version - body=#c_tuple{anno=[compiler_generated], - es=[#c_literal{val=[]}, Avar]}}, -%%% Multiple-value version -%%% body=#c_values{es=[#c_literal{val=[]}, A]}}, - Err = #c_tuple{es=[#c_literal{val='function_clause'}, F, Avar, Xs]}, - C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=match_fail([{function_name,{'lists^mapfoldr',2}}|Anno], Err)}, - Fun = #c_fun{vars=[Xs, Avar], - body=#c_case{arg=Xs, clauses=[C1, C2, C3]}}, - L = #c_var{name='L'}, - expr(#c_let{vars=[F, Avar, L], arg=#c_values{es=[Arg1, Arg2, Arg3]}, - body=#c_letrec{defs=[{Loop,Fun}], -%%% Tuple passing version - body=#c_apply{anno=Anno, - op=Loop, - args=[L, Avar]}}}, -%%% Multiple-value version -%%% body=#c_let{vars=[Xs, A], -%%% arg=#c_apply{op=Loop, -%%% args=[L, A]}, -%%% body=#c_tuple{es=[Xs, A]}}}}, - Sub); -call_1(#c_call{module=M, name=N}=Call, _, _, As, Sub) -> - call_0(Call, M, N, As, Sub). - -match_fail(Anno, Arg) -> - #c_primop{anno=Anno, - name=#c_literal{val='match_fail'}, - args=[Arg]}. - %% fold_call(Call, Mod, Name, Args, Sub) -> Expr. %% Try to safely evaluate the call. Just try to evaluate arguments, %% do the call and convert return values to literals. If this @@ -1133,29 +759,33 @@ fold_call_1(Call, Mod, Name, Args, Sub) -> true -> fold_call_2(Call, Mod, Name, Args, Sub) end. -fold_call_2(Call, Module, Name, Args0, Sub) -> - try - Args = [core_lib:literal_value(A) || A <- Args0], - try apply(Module, Name, Args) of - Val -> - case cerl:is_literal_term(Val) of - true -> - #c_literal{val=Val}; - false -> - %% Successful evaluation, but it was not - %% possible to express the computed value as a literal. - Call - end - catch - error:Reason -> - %% Evaluation of the function failed. Warn and replace - %% the call with a call to erlang:error/1. - eval_failure(Call, Reason) - end +fold_call_2(Call, Module, Name, Args, Sub) -> + case all(fun cerl:is_literal/1, Args) of + true -> + %% All arguments are literals. + fold_lit_args(Call, Module, Name, Args); + false -> + %% At least one non-literal argument. + fold_non_lit_args(Call, Module, Name, Args, Sub) + end. + +fold_lit_args(Call, Module, Name, Args0) -> + Args = [cerl:concrete(A) || A <- Args0], + try apply(Module, Name, Args) of + Val -> + case cerl:is_literal_term(Val) of + true -> + cerl:abstract(Val); + false -> + %% Successful evaluation, but it was not possible + %% to express the computed value as a literal. + Call + end catch - error:_ -> - %% There was at least one non-literal argument. - fold_non_lit_args(Call, Module, Name, Args0, Sub) + error:Reason -> + %% Evaluation of the function failed. Warn and replace + %% the call with a call to erlang:error/1. + eval_failure(Call, Reason) end. %% fold_non_lit_args(Call, Module, Name, Args, Sub) -> Expr. @@ -1194,36 +824,43 @@ fold_non_lit_args(Call, _, _, _, _) -> Call. %% Evaluate a relational operation using type information. eval_rel_op(Call, Op, [#c_var{name=V},#c_var{name=V}], _) -> Bool = erlang:Op(same, same), - #c_literal{anno=core_lib:get_anno(Call),val=Bool}; -eval_rel_op(Call, '=:=', [#c_var{name=V}=Var,#c_literal{val=true}], Sub) -> + #c_literal{anno=cerl:get_ann(Call),val=Bool}; +eval_rel_op(Call, '=:=', [Term,#c_literal{val=true}], Sub) -> %% BoolVar =:= true ==> BoolVar - case is_boolean_type(V, Sub) of - true -> Var; - false -> Call + case is_boolean_type(Term, Sub) of + yes -> Term; + maybe -> Call; + no -> #c_literal{val=false} end; -eval_rel_op(Call, '==', Ops, _Sub) -> - case is_exact_eq_ok(Ops) of +eval_rel_op(Call, '==', Ops, Sub) -> + case is_exact_eq_ok(Ops, Sub) of true -> - Name = #c_literal{anno=core_lib:get_anno(Call),val='=:='}, + Name = #c_literal{anno=cerl:get_ann(Call),val='=:='}, Call#c_call{name=Name}; false -> Call end; -eval_rel_op(Call, '/=', Ops, _Sub) -> - case is_exact_eq_ok(Ops) of +eval_rel_op(Call, '/=', Ops, Sub) -> + case is_exact_eq_ok(Ops, Sub) of true -> - Name = #c_literal{anno=core_lib:get_anno(Call),val='=/='}, + Name = #c_literal{anno=cerl:get_ann(Call),val='=/='}, Call#c_call{name=Name}; false -> Call end; eval_rel_op(Call, _, _, _) -> Call. -is_exact_eq_ok([#c_literal{val=Lit}|_]) -> +is_exact_eq_ok([A,B]=L, Sub) -> + case is_int_type(A, Sub) =:= yes andalso is_int_type(B, Sub) =:= yes of + true -> true; + false -> is_exact_eq_ok_1(L) + end. + +is_exact_eq_ok_1([#c_literal{val=Lit}|_]) -> is_non_numeric(Lit); -is_exact_eq_ok([_|T]) -> - is_exact_eq_ok(T); -is_exact_eq_ok([]) -> false. +is_exact_eq_ok_1([_|T]) -> + is_exact_eq_ok_1(T); +is_exact_eq_ok_1([]) -> false. is_non_numeric([H|T]) -> is_non_numeric(H) andalso is_non_numeric(T); @@ -1247,40 +884,31 @@ is_non_numeric_tuple(_Tuple, 0) -> true. %% there must be at least one non-literal argument (i.e. %% there is no need to handle the case that all argments %% are literal). -eval_bool_op(Call, 'and', [#c_literal{val=true},#c_var{name=V}=Res], Sub) -> - case is_boolean_type(V, Sub) of - true -> Res; - false-> Call - end; -eval_bool_op(Call, 'and', [#c_var{name=V}=Res,#c_literal{val=true}], Sub) -> - case is_boolean_type(V, Sub) of - true -> Res; - false-> Call - end; -eval_bool_op(Call, 'and', [#c_literal{val=false}=Res,#c_var{name=V}], Sub) -> - case is_boolean_type(V, Sub) of - true -> Res; - false-> Call - end; -eval_bool_op(Call, 'and', [#c_var{name=V},#c_literal{val=false}=Res], Sub) -> - case is_boolean_type(V, Sub) of - true -> Res; - false-> Call - end; + +eval_bool_op(Call, 'and', [#c_literal{val=true},Term], Sub) -> + eval_bool_op_1(Call, Term, Term, Sub); +eval_bool_op(Call, 'and', [Term,#c_literal{val=true}], Sub) -> + eval_bool_op_1(Call, Term, Term, Sub); +eval_bool_op(Call, 'and', [#c_literal{val=false}=Res,Term], Sub) -> + eval_bool_op_1(Call, Res, Term, Sub); +eval_bool_op(Call, 'and', [Term,#c_literal{val=false}=Res], Sub) -> + eval_bool_op_1(Call, Res, Term, Sub); eval_bool_op(Call, _, _, _) -> Call. +eval_bool_op_1(Call, Res, Term, Sub) -> + case is_boolean_type(Term, Sub) of + yes -> Res; + no -> eval_failure(Call, badarg); + maybe -> Call + end. + %% Evaluate is_boolean/1 using type information. -eval_is_boolean(Call, #c_var{name=V}, Sub) -> - case is_boolean_type(V, Sub) of - true -> #c_literal{val=true}; - false -> Call - end; -eval_is_boolean(_, #c_cons{}, _) -> - #c_literal{val=false}; -eval_is_boolean(_, #c_tuple{}, _) -> - #c_literal{val=false}; -eval_is_boolean(Call, _, _) -> - Call. +eval_is_boolean(Call, Term, Sub) -> + case is_boolean_type(Term, Sub) of + no -> #c_literal{val=false}; + yes -> #c_literal{val=true}; + maybe -> Call + end. %% eval_length(Call, List) -> Val. %% Evaluates the length for the prefix of List which has a known @@ -1330,36 +958,33 @@ eval_append(Call, X, Y) -> %% Evaluates element/2 if the position Pos is a literal and %% the shape of the tuple Tuple is known. %% -eval_element(Call, #c_literal{val=Pos}, #c_tuple{es=Es}, _Types) when is_integer(Pos) -> - if - 1 =< Pos, Pos =< length(Es) -> - lists:nth(Pos, Es); - true -> - eval_failure(Call, badarg) - end; -eval_element(Call, #c_literal{val=Pos}, #c_var{name=V}, Types) +eval_element(Call, #c_literal{val=Pos}, Tuple, Types) when is_integer(Pos) -> - case orddict:find(V, Types#sub.t) of - {ok,#c_tuple{es=Elements}} -> + case get_type(Tuple, Types) of + none -> + Call; + Type -> + Es = case cerl:is_c_tuple(Type) of + false -> []; + true -> cerl:tuple_es(Type) + end, if - 1 =< Pos, Pos =< length(Elements) -> - El = lists:nth(Pos, Elements), + 1 =< Pos, Pos =< length(Es) -> + El = lists:nth(Pos, Es), try - pat_to_expr(El) + cerl:set_ann(pat_to_expr(El), [compiler_generated]) catch throw:impossible -> Call end; true -> + %% Index outside tuple or not a tuple. eval_failure(Call, badarg) - end; - {ok,_} -> - eval_failure(Call, badarg); - error -> - Call + end end; -eval_element(Call, Pos, Tuple, _Types) -> - case is_not_integer(Pos) orelse is_not_tuple(Tuple) of +eval_element(Call, Pos, Tuple, Sub) -> + case is_int_type(Pos, Sub) =:= no orelse + is_tuple_type(Tuple, Sub) =:= no of true -> eval_failure(Call, badarg); false -> @@ -1369,58 +994,55 @@ eval_element(Call, Pos, Tuple, _Types) -> %% eval_is_record(Call, Var, Tag, Size, Types) -> Val. %% Evaluates is_record/3 using type information. %% -eval_is_record(Call, #c_var{name=V}, #c_literal{val=NeededTag}=Lit, +eval_is_record(Call, Term, #c_literal{val=NeededTag}, #c_literal{val=Size}, Types) -> - case orddict:find(V, Types#sub.t) of - {ok,#c_tuple{es=[#c_literal{val=Tag}|_]=Es}} -> - Lit#c_literal{val=Tag =:= NeededTag andalso - length(Es) =:= Size}; - _ -> - Call + case get_type(Term, Types) of + none -> + Call; + Type -> + Es = case cerl:is_c_tuple(Type) of + false -> []; + true -> cerl:tuple_es(Type) + end, + case Es of + [#c_literal{val=Tag}|_] -> + Bool = Tag =:= NeededTag andalso + length(Es) =:= Size, + #c_literal{val=Bool}; + _ -> + #c_literal{val=false} + end end; eval_is_record(Call, _, _, _, _) -> Call. -%% is_not_integer(Core) -> true | false. -%% Returns true if Core is definitely not an integer. - -is_not_integer(#c_literal{val=Val}) when not is_integer(Val) -> true; -is_not_integer(#c_tuple{}) -> true; -is_not_integer(#c_cons{}) -> true; -is_not_integer(#c_map{}) -> true; -is_not_integer(_) -> false. - -%% is_not_tuple(Core) -> true | false. -%% Returns true if Core is definitely not a tuple. - -is_not_tuple(#c_literal{val=Val}) when not is_tuple(Val) -> true; -is_not_tuple(#c_cons{}) -> true; -is_not_tuple(#c_map{}) -> true; -is_not_tuple(_) -> false. - %% eval_setelement(Call, Pos, Tuple, NewVal) -> Core. %% Evaluates setelement/3 if position Pos is an integer -%% the shape of the tuple Tuple is known. +%% and the shape of the tuple Tuple is known. %% -eval_setelement(Call, Pos, Tuple, NewVal) -> - try - eval_setelement_1(Pos, Tuple, NewVal) - catch - error:_ -> - Call - end. - -eval_setelement_1(#c_literal{val=Pos}, #c_tuple{anno=A,es=Es}, NewVal) +eval_setelement(Call, #c_literal{val=Pos}, Tuple, NewVal) when is_integer(Pos) -> - ann_c_tuple(A, eval_setelement_2(Pos, Es, NewVal)); -eval_setelement_1(#c_literal{val=Pos}, #c_literal{anno=A,val=Es0}, NewVal) - when is_integer(Pos) -> - Es = [#c_literal{anno=A,val=E} || E <- tuple_to_list(Es0)], - ann_c_tuple(A, eval_setelement_2(Pos, Es, NewVal)). + case cerl:is_data(Tuple) of + false -> + Call; + true -> + Es0 = case cerl:is_c_tuple(Tuple) of + false -> []; + true -> cerl:tuple_es(Tuple) + end, + if + 1 =< Pos, Pos =< length(Es0) -> + Es = eval_setelement_1(Pos, Es0, NewVal), + cerl:update_c_tuple(Tuple, Es); + true -> + eval_failure(Call, badarg) + end + end; +eval_setelement(Call, _, _, _) -> Call. -eval_setelement_2(1, [_|T], NewVal) -> +eval_setelement_1(1, [_|T], NewVal) -> [NewVal|T]; -eval_setelement_2(Pos, [H|T], NewVal) when Pos > 1 -> - [H|eval_setelement_2(Pos-1, T, NewVal)]. +eval_setelement_1(Pos, [H|T], NewVal) when Pos > 1 -> + [H|eval_setelement_1(Pos-1, T, NewVal)]. %% eval_failure(Call, Reason) -> Core. %% Warn for a call that will fail and replace the call with @@ -1500,20 +1122,32 @@ clause(#c_clause{pats=Ps0,guard=G0,body=B0}=Cl, Cexpr, Ctxt, Sub0) -> let_substs(Vs0, As0, Sub0) -> {Vs1,Sub1} = pattern_list(Vs0, Sub0), {Vs2,As1,Ss} = let_substs_1(Vs1, As0, Sub1), - Sub2 = scope_add([V || #c_var{name=V} <- Vs2], Sub1), + Sub2 = sub_add_scope([V || #c_var{name=V} <- Vs2], Sub1), {Vs2,As1, - foldl(fun ({V,S}, Sub) -> sub_set_name(V, S, Sub) end, Sub2, Ss)}. + foldl(fun ({V,S}, Sub) -> sub_set_name(V, S, Sub) end, Sub2, Ss)}. let_substs_1(Vs, #c_values{es=As}, Sub) -> let_subst_list(Vs, As, Sub); let_substs_1([V], A, Sub) -> let_subst_list([V], [A], Sub); let_substs_1(Vs, A, _) -> {Vs,A,[]}. -let_subst_list([V|Vs0], [A|As0], Sub) -> +let_subst_list([V|Vs0], [A0|As0], Sub) -> {Vs1,As1,Ss} = let_subst_list(Vs0, As0, Sub), - case is_subst(A) of - true -> {Vs1,As1,sub_subst_var(V, A, Sub) ++ Ss}; - false -> {[V|Vs1],[A|As1],Ss} + case is_subst(A0) of + true -> + A = case is_compiler_generated(V) andalso + not is_compiler_generated(A0) of + true -> + %% Propagate the 'compiler_generated' annotation + %% along with the value. + Ann = [compiler_generated|cerl:get_ann(A0)], + cerl:set_ann(A0, Ann); + false -> + A0 + end, + {Vs1,As1,sub_subst_var(V, A, Sub) ++ Ss}; + false -> + {[V|Vs1],[A0|As1],Ss} end; let_subst_list([], [], _) -> {[],[],[]}. @@ -1535,7 +1169,7 @@ pattern(#c_var{}=Pat, Isub, Osub) -> true -> V1 = make_var_name(), Pat1 = #c_var{name=V1}, - {Pat1,sub_set_var(Pat, Pat1, scope_add([V1], Osub))}; + {Pat1,sub_set_var(Pat, Pat1, sub_add_scope([V1], Osub))}; false -> {Pat,sub_del_var(Pat, Osub)} end; @@ -1605,6 +1239,7 @@ is_subst(_) -> false. %% sub_del_var(Var, #sub{}) -> #sub{}. %% sub_subst_var(Var, Value, #sub{}) -> [{Name,Value}]. %% sub_is_val(Var, #sub{}) -> boolean(). +%% sub_add_scope(#sub{}) -> #sub{} %% sub_subst_scope(#sub{}) -> #sub{} %% %% We use the variable name as key so as not have problems with @@ -1615,14 +1250,15 @@ is_subst(_) -> false. %% In addition to the list of substitutions, we also keep track of %% all variable currently live (the scope). %% -%% sub_subst_scope/1 adds dummy substitutions for all variables -%% in the scope in order to force renaming if variables in the -%% scope occurs as pattern variables. +%% sub_add_scope/2 adds variables to the scope. sub_subst_scope/1 +%% adds dummy substitutions for all variables in the scope in order +%% to force renaming if variables in the scope occurs as pattern +%% variables. -sub_new() -> #sub{v=orddict:new(),s=gb_trees:empty(),t=[]}. +sub_new() -> #sub{v=orddict:new(),s=cerl_sets:new(),t=#{}}. sub_new(#sub{}=Sub) -> - Sub#sub{v=orddict:new(),t=[]}. + Sub#sub{v=orddict:new(),t=#{}}. sub_new_preserve_types(#sub{}=Sub) -> Sub#sub{v=orddict:new()}. @@ -1639,16 +1275,16 @@ sub_set_var(#c_var{name=V}, Val, Sub) -> sub_set_name(V, Val, #sub{v=S,s=Scope,t=Tdb0}=Sub) -> Tdb1 = kill_types(V, Tdb0), Tdb = copy_type(V, Val, Tdb1), - Sub#sub{v=orddict:store(V, Val, S),s=gb_sets:add(V, Scope),t=Tdb}. + Sub#sub{v=orddict:store(V, Val, S),s=cerl_sets:add_element(V, Scope),t=Tdb}. sub_del_var(#c_var{name=V}, #sub{v=S,s=Scope,t=Tdb}=Sub) -> %% Profiling shows that for programs with many record operations, %% sub_del_var/2 is a bottleneck. Since the scope contains all %% variables that are live, we know that V cannot be present in S %% if it is not in the scope. - case gb_sets:is_member(V, Scope) of + case cerl_sets:is_element(V, Scope) of false -> - Sub#sub{s=gb_sets:insert(V, Scope)}; + Sub#sub{s=cerl_sets:add_element(V, Scope)}; true -> Sub#sub{v=orddict:erase(V, S),t=kill_types(V, Tdb)} end. @@ -1657,8 +1293,14 @@ sub_subst_var(#c_var{name=V}, Val, #sub{v=S0}) -> %% Fold chained substitutions. [{V,Val}] ++ [ {K,Val} || {K,#c_var{name=V1}} <- S0, V1 =:= V]. +sub_add_scope(Vs, #sub{s=Scope0}=Sub) -> + Scope = foldl(fun(V, S) when is_integer(V); is_atom(V) -> + cerl_sets:add_element(V, S) + end, Scope0, Vs), + Sub#sub{s=Scope}. + sub_subst_scope(#sub{v=S0,s=Scope}=Sub) -> - S = [{-1,#c_var{name=Sv}} || Sv <- gb_sets:to_list(Scope)]++S0, + S = [{-1,#c_var{name=Sv}} || Sv <- cerl_sets:to_list(Scope)]++S0, Sub#sub{v=S}. sub_is_val(#c_var{name=V}, #sub{v=S,s=Scope}) -> @@ -1666,7 +1308,7 @@ sub_is_val(#c_var{name=V}, #sub{v=S,s=Scope}) -> %% became the new bottleneck. Since the scope contains all %% live variables, a variable V can only be the target for %% a substitution if it is in the scope. - gb_sets:is_member(V, Scope) andalso v_is_value(V, S). + cerl_sets:is_element(V, Scope) andalso v_is_value(V, S). v_is_value(Var, [{_,#c_var{name=Var}}|_]) -> true; v_is_value(Var, [_|T]) -> v_is_value(Var, T); @@ -1704,7 +1346,7 @@ clauses(E, [C0|Cs], Ctxt, Sub, LitExpr) -> {yes,yes} -> case LitExpr of false -> - Line = get_line(core_lib:get_anno(C1)), + Line = get_line(cerl:get_ann(C1)), shadow_warning(Cs, Line); true -> %% If the case expression is a literal, @@ -1938,7 +1580,7 @@ opt_bool_case_guard(#c_case{arg=Arg,clauses=Cs0}=Case) -> Case; true -> Cs = opt_bool_case_guard(Arg, Cs0), - Case#c_case{arg=#c_values{anno=core_lib:get_anno(Arg),es=[]}, + Case#c_case{arg=#c_values{anno=cerl:get_ann(Arg),es=[]}, clauses=Cs} end. @@ -1986,6 +1628,7 @@ eval_case(#c_case{arg=E,clauses=[#c_clause{pats=Ps0, %% is correct, the clause will always match at run-time. Case; {true,Bs} -> + eval_case_warn(B), {Ps,As} = unzip(Bs), InnerLet = cerl:c_let(Ps, core_lib:make_values(As), B), Let = cerl:c_let(Vs, E, InnerLet), @@ -1993,6 +1636,18 @@ eval_case(#c_case{arg=E,clauses=[#c_clause{pats=Ps0, end; eval_case(Case, _) -> Case. +eval_case_warn(#c_primop{anno=Anno, + name=#c_literal{val=match_fail}, + args=[_]}=Core) -> + case keyfind(eval_failure, 1, Anno) of + false -> + ok; + {eval_failure,Reason} -> + %% Example: M = not_map, M#{k:=v} + add_warning(Core, {eval_failure,Reason}) + end; +eval_case_warn(_) -> ok. + %% case_opt(CaseArg, [Clause]) -> {CaseArg,[Clause]}. %% Try and optimise a case by avoid building tuples or lists %% in the case expression. Instead combine the variable parts @@ -2048,12 +1703,31 @@ case_opt_args([], Cs, _Sub, _LitExpr, Acc) -> %% Try to expand one argument to several arguments (if tuple/list) %% or to remove a literal argument. %% -case_opt_arg(E0, Sub, Cs0, LitExpr) -> - E = maybe_replace_var(E0, Sub), - case cerl:is_data(E) of +case_opt_arg(E0, Sub, Cs, LitExpr) -> + case cerl:is_c_var(E0) of + false -> + case_opt_arg_1(E0, Cs, LitExpr); + true -> + case case_will_var_match(Cs) of + true -> + %% All clauses will match a variable in the + %% current position. Don't expand this variable + %% (that can only make the code worse). + {error,Cs}; + false -> + %% If possible, expand this variable to a previously + %% matched term. + E = case_expand_var(E0, Sub), + case_opt_arg_1(E, Cs, LitExpr) + end + end. + +case_opt_arg_1(E0, Cs0, LitExpr) -> + case cerl:is_data(E0) of false -> {error,Cs0}; true -> + E = case_opt_compiler_generated(E0), Cs = case_opt_nomatch(E, Cs0, LitExpr), case cerl:data_type(E) of {atomic,_} -> @@ -2063,20 +1737,45 @@ case_opt_arg(E0, Sub, Cs0, LitExpr) -> end end. -%% maybe_replace_var(Expr0, Sub) -> Expr +%% case_will_var_match([Clause]) -> true | false. +%% Return if all clauses will match a variable in the +%% current position. +%% +case_will_var_match(Cs) -> + all(fun({[P|_],_,_,_}) -> + case cerl_clauses:match(P, any) of + {true,_} -> true; + _ -> false + end + end, Cs). + + +%% case_opt_compiler_generated(Core) -> Core' +%% Mark Core expressions as compiler generated to ensure that +%% no warnings are generated if they turn out to be unused. +%% To pretty-printed Core Erlang easier to read, don't mark +%% constructs that can't cause warnings to be emitted. +%% +case_opt_compiler_generated(Core) -> + F = fun(C) -> + case cerl:type(C) of + alias -> C; + var -> C; + _ -> cerl:set_ann(C, [compiler_generated]) + end + end, + cerl_trees:map(F, Core). + + +%% case_expand_var(Expr0, Sub) -> Expr %% If Expr0 is a variable that has been previously matched and %% is known to be a tuple, return the tuple instead. Otherwise %% return Expr0 unchanged. %% -maybe_replace_var(E, Sub) -> - case cerl:is_c_var(E) of - false -> E; - true -> maybe_replace_var_1(E, Sub) - end. - -maybe_replace_var_1(E, #sub{t=Tdb}) -> - case orddict:find(cerl:var_name(E), Tdb) of - {ok,T0} -> +case_expand_var(E, #sub{t=Tdb}) -> + Key = cerl:var_name(E), + case Tdb of + #{Key:=T0} -> case cerl:is_c_tuple(T0) of false -> E; @@ -2091,9 +1790,8 @@ maybe_replace_var_1(E, #sub{t=Tdb}) -> %% operator will fail when used in map %% construction (only the '=>' operator is allowed %% when constructing a map from scratch). - ToData = fun coerce_to_data/1, try - cerl_trees:map(ToData, T0) + cerl_trees:map(fun coerce_to_data/1, T0) catch throw:impossible -> %% Something unsuitable was found (map or @@ -2101,7 +1799,7 @@ maybe_replace_var_1(E, #sub{t=Tdb}) -> E end end; - error -> + _ -> E end. @@ -2147,8 +1845,9 @@ case_opt_nomatch(_, [], _) -> []. %% will match, and we can remove the corresponding pattern from %% each clause. %% -%% The only complication is if the literal is a binary. Binary -%% pattern matching is tricky, so we will give up in that case. +%% The only complication is if the literal is a binary or map. +%% In general, it is difficult to know whether a binary or +%% map pattern will match, so we give up in that case. case_opt_lit(Lit, Cs0) -> try case_opt_lit_1(Lit, Cs0) of @@ -2175,6 +1874,10 @@ case_opt_lit_1(E, [{[P|Ps],C,PsAcc,Bs0}|Cs]) -> case_opt_lit_1(_, []) -> []. %% case_opt_data(Expr, Clauses0, LitExpr) -> {ok,Exprs,Clauses} +%% The case expression is a non-atomic data constructor (cons +%% or tuple). We can know at compile time whether each clause +%% will match, and we can delay the building of the data to +%% the clauses where it is actually needed. case_opt_data(E, Cs0) -> Es = cerl:data_es(E), @@ -2184,45 +1887,48 @@ case_opt_data(E, Cs0) -> {ok,Es,Cs} catch throw:impossible -> + %% The pattern contained a binary or map. {error,Cs0} end. -case_opt_data_1([{[P|Ps0],C,PsAcc,Bs0}|Cs], Es, TypeSig) -> - {ok,Ps1,Bs1} = case_data_pat(P, TypeSig), - [{Ps1++Ps0,C,PsAcc,Bs1++Bs0}| - case_opt_data_1(Cs, Es, TypeSig)]; +case_opt_data_1([{[P0|Ps0],C,PsAcc,Bs0}|Cs], Es, TypeSig) -> + P = case_opt_compiler_generated(P0), + BindTo = #c_var{name=dummy}, + {Ps1,[{BindTo,_}|Bs1]} = case_data_pat_alias(P, BindTo, TypeSig, []), + [{Ps1++Ps0,C,PsAcc,Bs1++Bs0}|case_opt_data_1(Cs, Es, TypeSig)]; case_opt_data_1([], _, _) -> []. -%% case_data_pat(Pattern, Type, Arity) -> {ok,[Pattern],[{AliasVar,Pat}]} | error. - -case_data_pat(P, TypeSig) -> - case cerl:is_data(P) of - false -> - case_data_pat_var(P, TypeSig); - true -> - {ok,cerl:data_es(P),[]} - end. - -%% case_data_pat_var(Pattern, {DataType,ArityType}) -> -%% {ok,[Pattern],[{AliasVar,Pat}]} - -case_data_pat_var(P, {Type,Arity}=TypeSig) -> - %% If the entire case statement is evaluated in an effect - %% context (e.g. "case {A,B} of ... end, ok"), there will - %% be a warning that a term is constructed but never used. - %% To avoid that warning, we must annotate the data - %% constructor as compiler generated. - Ann = [compiler_generated|cerl:get_ann(P)], +case_data_pat_alias(P, BindTo0, TypeSig, Bs0) -> case cerl:type(P) of - var -> - Vars = make_vars(cerl:get_ann(P), Arity), - {ok,Vars,[{P,cerl:ann_make_data(Ann, Type, Vars)}]}; alias -> - V = cerl:alias_var(P), - Apat = cerl:alias_pat(P), - {ok,Ps,Bs} = case_data_pat(Apat, TypeSig), - {ok,Ps,[{V,cerl:ann_make_data(Ann, Type, - pat_to_expr_list(Ps))}|Bs]} + %% Recursively handle the pattern and bind to + %% the alias variable. + BindTo = cerl:alias_var(P), + Apat0 = cerl:alias_pat(P), + Ann = [compiler_generated], + Apat = cerl:set_ann(Apat0, Ann), + {Ps,Bs} = case_data_pat_alias(Apat, BindTo, TypeSig, Bs0), + {Ps,[{BindTo0,BindTo}|Bs]}; + var -> + %% Here we will need to actually build the data and bind + %% it to the variable. + {Type,Arity} = TypeSig, + Ann = [compiler_generated], + Vars = make_vars(Ann, Arity), + Data = cerl:ann_make_data(Ann, Type, Vars), + Bs = [{BindTo0,P},{P,Data}|Bs0], + {Vars,Bs}; + _ -> + %% Since case_opt_nomatch/3 has removed all clauses that + %% cannot match, we KNOW that this clause must match and + %% that the pattern must be a data constructor. + %% Here we must build the data and bind it to the variable. + {Type,_} = TypeSig, + DataEs = cerl:data_es(P), + Vars = pat_to_expr_list(DataEs), + Ann = [compiler_generated], + Data = cerl:ann_make_data(Ann, Type, Vars), + {DataEs,[{BindTo0,Data}]} end. %% pat_to_expr(Pattern) -> Expression. @@ -2269,58 +1975,130 @@ make_var_name() -> list_to_atom("fol"++integer_to_list(N)). letify(Bs, Body) -> + Ann = cerl:get_ann(Body), foldr(fun({V,Val}, B) -> - letify(V, Val, B) + cerl:ann_c_let(Ann, [V], Val, B) end, Body, Bs). -letify(#c_var{name=Vname}=Var, Val, Body) -> - case core_lib:is_var_used(Vname, Body) of - true -> - A = element(2, Body), - #c_let{anno=A,vars=[Var],arg=Val,body=Body}; - false -> Body - end. - -%% opt_case_in_let(LetExpr) -> LetExpr' +%% opt_not_in_let(Let) -> Cerl +%% Try to optimize away a 'not' operator in a 'let'. -opt_case_in_let(#c_let{vars=Vs,arg=Arg,body=B}=Let, Sub) -> - opt_case_in_let_0(Vs, Arg, B, Let, Sub). +-spec opt_not_in_let(cerl:c_let()) -> cerl:cerl(). -opt_case_in_let_0([#c_var{name=V}], Arg, - #c_case{arg=#c_var{name=V},clauses=Cs}=Case, Let, Sub) -> - case opt_case_in_let_1(V, Arg, Cs) of - impossible -> - case is_simple_case_arg(Arg) andalso - not core_lib:is_var_used(V, Case#c_case{arg=#c_literal{val=nil}}) of - true -> - expr(opt_bool_case(Case#c_case{arg=Arg,clauses=Cs}), sub_new(Sub)); - false -> - Let +opt_not_in_let(#c_let{vars=[_]=Vs0,arg=Arg0,body=Body0}=Let) -> + case opt_not_in_let(Vs0, Arg0, Body0) of + {[],#c_values{es=[]},Body} -> + Body; + {Vs,Arg,Body} -> + Let#c_let{vars=Vs,arg=Arg,body=Body} + end; +opt_not_in_let(Let) -> Let. + +%% opt_not_in_let(Vs, Arg, Body) -> {Vs',Arg',Body'} +%% Try to optimize away a 'not' operator in a 'let'. + +-spec opt_not_in_let([cerl:c_var()], cerl:cerl(), cerl:cerl()) -> + {[cerl:c_var()],cerl:cerl(),cerl:cerl()}. + +opt_not_in_let([#c_var{name=V}]=Vs0, Arg0, Body0) -> + case cerl:type(Body0) of + call -> + %% let <V> = Expr in not V ==> + %% let <> = <> in notExpr + case opt_not_in_let_1(V, Body0, Arg0) of + no -> + {Vs0,Arg0,Body0}; + {yes,Body} -> + {[],#c_values{es=[]},Body} end; - Expr -> Expr + 'let' -> + %% let <V> = Expr in let <Var> = not V in Body ==> + %% let <Var> = notExpr in Body + %% V must not be used in Body. + LetArg = cerl:let_arg(Body0), + case opt_not_in_let_1(V, LetArg, Arg0) of + no -> + {Vs0,Arg0,Body0}; + {yes,Arg} -> + LetBody = cerl:let_body(Body0), + case core_lib:is_var_used(V, LetBody) of + true -> + {Vs0,Arg0,Body0}; + false -> + LetVars = cerl:let_vars(Body0), + {LetVars,Arg,LetBody} + end + end; + _ -> + {Vs0,Arg0,Body0} end; -opt_case_in_let_0(_, _, _, Let, _) -> Let. +opt_not_in_let(Vs, Arg, Body) -> + {Vs,Arg,Body}. -opt_case_in_let_1(V, Arg, Cs) -> - try - opt_case_in_let_2(V, Arg, Cs) - catch - _:_ -> impossible +opt_not_in_let_1(V, Call, Body) -> + case Call of + #c_call{module=#c_literal{val=erlang}, + name=#c_literal{val='not'}, + args=[#c_var{name=V}]} -> + opt_not_in_let_2(Body); + _ -> + no end. -opt_case_in_let_2(V, Arg0, - [#c_clause{pats=[#c_tuple{es=Es}], - guard=#c_literal{val=true},body=B}|_]) -> - - %% In {V1,V2,...} = case E of P -> ... {Val1,Val2,...}; ... end. - %% avoid building tuples, by converting tuples to multiple values. - %% (The optimisation is not done if the built tuple is used or returned.) - - true = all(fun (#c_var{}) -> true; - (_) -> false end, Es), %Only variables in tuple - false = core_lib:is_var_used(V, B), %Built tuple must not be used. - Arg1 = tuple_to_values(Arg0, length(Es)), %Might fail. - #c_let{vars=Es,arg=Arg1,body=B}. +opt_not_in_let_2(#c_case{clauses=Cs0}=Case) -> + Vars = make_vars([], 1), + Body = #c_call{module=#c_literal{val=erlang}, + name=#c_literal{val='not'}, + args=Vars}, + Cs = [begin + Let = #c_let{vars=Vars,arg=B,body=Body}, + C#c_clause{body=opt_not_in_let(Let)} + end || #c_clause{body=B}=C <- Cs0], + {yes,Case#c_case{clauses=Cs}}; +opt_not_in_let_2(#c_call{}=Call0) -> + invert_call(Call0); +opt_not_in_let_2(_) -> no. + +invert_call(#c_call{module=#c_literal{val=erlang}, + name=#c_literal{val=Name0}, + args=[_,_]}=Call) -> + case inverse_rel_op(Name0) of + no -> no; + Name -> {yes,Call#c_call{name=#c_literal{val=Name}}} + end; +invert_call(#c_call{}) -> no. + +%% inverse_rel_op(Op) -> no | RevOp + +inverse_rel_op('=:=') -> '=/='; +inverse_rel_op('=/=') -> '=:='; +inverse_rel_op('==') -> '/='; +inverse_rel_op('/=') -> '=='; +inverse_rel_op('>') -> '=<'; +inverse_rel_op('<') -> '>='; +inverse_rel_op('>=') -> '<'; +inverse_rel_op('=<') -> '>'; +inverse_rel_op(_) -> no. + + +%% opt_bool_case_in_let(LetExpr, Sub) -> Core + +opt_bool_case_in_let(#c_let{vars=Vs,arg=Arg,body=B}=Let, Sub) -> + opt_case_in_let_1(Vs, Arg, B, Let, Sub). + +opt_case_in_let_1([#c_var{name=V}], Arg, + #c_case{arg=#c_var{name=V}}=Case0, Let, Sub) -> + case is_simple_case_arg(Arg) of + true -> + Case = opt_bool_case(Case0#c_case{arg=Arg}), + case core_lib:is_var_used(V, Case) of + false -> expr(Case, sub_new(Sub)); + true -> Let + end; + false -> + Let + end; +opt_case_in_let_1(_, _, _, Let, _) -> Let. %% is_simple_case_arg(Expr) -> true|false %% Determine whether the Expr is simple enough to be worth @@ -2362,18 +2140,15 @@ is_bool_expr(#c_clause{body=B}, Sub) -> is_bool_expr(B, Sub); is_bool_expr(#c_let{vars=[V],arg=Arg,body=B}, Sub0) -> Sub = case is_bool_expr(Arg, Sub0) of - true -> update_types(V, [#c_literal{val=true}], Sub0); + true -> update_types(V, [bool], Sub0); false -> Sub0 end, is_bool_expr(B, Sub); is_bool_expr(#c_let{body=B}, Sub) -> %% Binding of multiple variables. is_bool_expr(B, Sub); -is_bool_expr(#c_literal{val=Bool}, _) when is_boolean(Bool) -> - true; -is_bool_expr(#c_var{name=V}, Sub) -> - is_boolean_type(V, Sub); -is_bool_expr(_, _) -> false. +is_bool_expr(C, Sub) -> + is_boolean_type(C, Sub) =:= yes. is_bool_expr_list([C|Cs], Sub) -> is_bool_expr(C, Sub) andalso is_bool_expr_list(Cs, Sub); @@ -2386,7 +2161,7 @@ is_bool_expr_list([], _) -> true. %% functions, or is_record/2). %% is_safe_bool_expr(Core, Sub) -> - is_safe_bool_expr_1(Core, Sub, gb_sets:empty()). + is_safe_bool_expr_1(Core, Sub, cerl_sets:new()). is_safe_bool_expr_1(#c_call{module=#c_literal{val=erlang}, name=#c_literal{val=is_record}, @@ -2432,7 +2207,7 @@ is_safe_bool_expr_1(#c_let{vars=Vars,arg=Arg,body=B}, Sub, BoolVars) -> true -> case {is_safe_bool_expr_1(Arg, Sub, BoolVars),Vars} of {true,[#c_var{name=V}]} -> - is_safe_bool_expr_1(B, Sub, gb_sets:add(V, BoolVars)); + is_safe_bool_expr_1(B, Sub, cerl_sets:add_element(V, BoolVars)); {false,_} -> is_safe_bool_expr_1(B, Sub, BoolVars) end; @@ -2441,7 +2216,7 @@ is_safe_bool_expr_1(#c_let{vars=Vars,arg=Arg,body=B}, Sub, BoolVars) -> is_safe_bool_expr_1(#c_literal{val=Val}, _Sub, _) -> is_boolean(Val); is_safe_bool_expr_1(#c_var{name=V}, _Sub, BoolVars) -> - gb_sets:is_element(V, BoolVars); + cerl_sets:is_element(V, BoolVars); is_safe_bool_expr_1(_, _, _) -> false. is_safe_bool_expr_list([C|Cs], Sub, BoolVars) -> @@ -2451,38 +2226,6 @@ is_safe_bool_expr_list([C|Cs], Sub, BoolVars) -> end; is_safe_bool_expr_list([], _, _) -> true. -%% tuple_to_values(Expr, TupleArity) -> Expr' -%% Convert tuples in return position of arity TupleArity to values. -%% Throws an exception for constructs that are not handled. - -tuple_to_values(#c_tuple{es=Es}, Arity) when length(Es) =:= Arity -> - core_lib:make_values(Es); -tuple_to_values(#c_literal{val=Tuple}=Lit, Arity) when tuple_size(Tuple) =:= Arity -> - Es = [Lit#c_literal{val=E} || E <- tuple_to_list(Tuple)], - core_lib:make_values(Es); -tuple_to_values(#c_case{clauses=Cs0}=Case, Arity) -> - Cs1 = [tuple_to_values(E, Arity) || E <- Cs0], - Case#c_case{clauses=Cs1}; -tuple_to_values(#c_seq{body=B0}=Seq, Arity) -> - Seq#c_seq{body=tuple_to_values(B0, Arity)}; -tuple_to_values(#c_let{body=B0}=Let, Arity) -> - Let#c_let{body=tuple_to_values(B0, Arity)}; -tuple_to_values(#c_receive{clauses=Cs0,timeout=Timeout,action=A0}=Rec, Arity) -> - Cs = [tuple_to_values(E, Arity) || E <- Cs0], - A = case Timeout of - #c_literal{val=infinity} -> A0; - _ -> tuple_to_values(A0, Arity) - end, - Rec#c_receive{clauses=Cs,action=A}; -tuple_to_values(#c_clause{body=B0}=Clause, Arity) -> - B = tuple_to_values(B0, Arity), - Clause#c_clause{body=B}; -tuple_to_values(Expr, _) -> - case will_fail(Expr) of - true -> Expr; - false -> erlang:error({not_handled,Expr}) - end. - %% simplify_let(Let, Sub) -> Expr | impossible %% If the argument part of an let contains a complex expression, such %% as a let or a sequence, move the original let body into the complex @@ -2507,9 +2250,9 @@ move_let_into_expr(#c_let{vars=InnerVs0,body=InnerBody0}=Inner, %% in <InnerBody> %% Arg = body(Arg0, Sub0), - ScopeSub0 = sub_subst_scope(Sub0#sub{t=[]}), + ScopeSub0 = sub_subst_scope(Sub0#sub{t=#{}}), {OuterVs,ScopeSub} = pattern_list(OuterVs0, ScopeSub0), - + OuterBody = body(OuterBody0, ScopeSub), {InnerVs,Sub} = pattern_list(InnerVs0, Sub0), @@ -2546,15 +2289,15 @@ move_let_into_expr(#c_let{vars=Lvs0,body=Lbody0}=Let, CaVars0 = Ca0#c_clause.pats, G0 = Ca0#c_clause.guard, B0 = Ca0#c_clause.body, - ScopeSub0 = sub_subst_scope(Sub0#sub{t=[]}), + ScopeSub0 = sub_subst_scope(Sub0#sub{t=#{}}), {CaVars,ScopeSub} = pattern_list(CaVars0, ScopeSub0), G = guard(G0, ScopeSub), B1 = body(B0, ScopeSub), {Lvs,B2,Sub1} = let_substs(Lvs0, B1, Sub0), - Sub2 = Sub1#sub{s=gb_sets:union(ScopeSub#sub.s, - Sub1#sub.s)}, + Sub2 = Sub1#sub{s=cerl_sets:union(ScopeSub#sub.s, + Sub1#sub.s)}, Lbody = body(Lbody0, Sub2), B = Let#c_let{vars=Lvs,arg=core_lib:make_values(B2),body=Lbody}, @@ -2587,88 +2330,257 @@ move_let_into_expr(_Let, _Expr, _Sub) -> impossible. is_failing_clause(#c_clause{body=B}) -> will_fail(B). -scope_add(Vs, #sub{s=Scope0}=Sub) -> - Scope = foldl(fun(V, S) when is_integer(V); is_atom(V) -> - gb_sets:add(V, S) - end, Scope0, Vs), - Sub#sub{s=Scope}. +%% opt_case_in_let(Let) -> Let' +%% Try to avoid building tuples that are immediately matched. +%% A common pattern is: +%% +%% {V1,V2,...} = case E of P -> ... {Val1,Val2,...}; ... end +%% +%% In Core Erlang the pattern would look like this: +%% +%% let <V> = case E of +%% ... -> ... {Val1,Val2} +%% ... +%% end, +%% in case V of +%% {A,B} -> ... <use A and B> ... +%% end +%% +%% Rewrite this to: +%% +%% let <V1,V2> = case E of +%% ... -> ... <Val1,Val2> +%% ... +%% end, +%% in +%% let <V> = {V1,V2} +%% in case V of +%% {A,B} -> ... <use A and B> ... +%% end +%% +%% Note that the second 'case' is unchanged. The other optimizations +%% in this module will eliminate the building of the tuple and +%% rewrite the second case to: +%% +%% case <V1,V2> of +%% <A,B> -> ... <use A and B> ... +%% end +%% + +opt_case_in_let(#c_let{vars=Vs,arg=Arg0,body=B}=Let0) -> + case matches_data(Vs, B) of + {yes,TypeSig} -> + case delay_build(Arg0, TypeSig) of + no -> + Let0; + {yes,Vars,Arg,Data} -> + InnerLet = Let0#c_let{arg=Data}, + Let0#c_let{vars=Vars,arg=Arg,body=InnerLet} + end; + no -> + Let0 + end. + +matches_data([#c_var{name=V}], #c_case{arg=#c_var{name=V}, + clauses=[#c_clause{pats=[P]}|_]}) -> + case cerl:is_data(P) of + false -> + no; + true -> + case cerl:data_type(P) of + {atomic,_} -> + no; + Type -> + {yes,{Type,cerl:data_arity(P)}} + end + end; +matches_data(_, _) -> no. + +delay_build(Core, TypeSig) -> + case cerl:is_data(Core) of + true -> no; + false -> delay_build_1(Core, TypeSig) + end. + +delay_build_1(Core0, TypeSig) -> + try delay_build_expr(Core0, TypeSig) of + Core -> + {Type,Arity} = TypeSig, + Ann = [compiler_generated], + Vars = make_vars(Ann, Arity), + Data = cerl:ann_make_data(Ann, Type, Vars), + {yes,Vars,Core,Data} + catch + throw:impossible -> + no + end. + +delay_build_cs([#c_clause{body=B0}=C0|Cs], TypeSig) -> + B = delay_build_expr(B0, TypeSig), + C = C0#c_clause{body=B}, + [C|delay_build_cs(Cs, TypeSig)]; +delay_build_cs([], _) -> []. + +delay_build_expr(Core, {Type,Arity}=TypeSig) -> + case cerl:is_data(Core) of + false -> + delay_build_expr_1(Core, TypeSig); + true -> + case {cerl:data_type(Core),cerl:data_arity(Core)} of + {Type,Arity} -> + core_lib:make_values(cerl:data_es(Core)); + {_,_} -> + throw(impossible) + end + end. + +delay_build_expr_1(#c_case{clauses=Cs0}=Case, TypeSig) -> + Cs = delay_build_cs(Cs0, TypeSig), + Case#c_case{clauses=Cs}; +delay_build_expr_1(#c_let{body=B0}=Let, TypeSig) -> + B = delay_build_expr(B0, TypeSig), + Let#c_let{body=B}; +delay_build_expr_1(#c_receive{clauses=Cs0, + timeout=Timeout, + action=A0}=Rec, TypeSig) -> + Cs = delay_build_cs(Cs0, TypeSig), + A = case Timeout of + #c_literal{val=infinity} -> A0; + _ -> delay_build_expr(A0, TypeSig) + end, + Rec#c_receive{clauses=Cs,action=A}; +delay_build_expr_1(#c_seq{body=B0}=Seq, TypeSig) -> + B = delay_build_expr(B0, TypeSig), + Seq#c_seq{body=B}; +delay_build_expr_1(Core, _TypeSig) -> + case will_fail(Core) of + true -> Core; + false -> throw(impossible) + end. %% opt_simple_let(#c_let{}, Context, Sub) -> CoreTerm %% Optimize a let construct that does not contain any lets in %% in its argument. -opt_simple_let(#c_let{arg=Arg0}=Let, Ctxt, Sub0) -> - Arg = body(Arg0, value, Sub0), %This is a body +opt_simple_let(Let0, Ctxt, Sub) -> + case opt_not_in_let(Let0) of + #c_let{}=Let -> + opt_simple_let_0(Let, Ctxt, Sub); + Expr -> + expr(Expr, Ctxt, Sub) + end. + +opt_simple_let_0(#c_let{arg=Arg0}=Let, Ctxt, Sub) -> + Arg = body(Arg0, value, Sub), %This is a body case will_fail(Arg) of true -> Arg; - false -> opt_simple_let_1(Let, Arg, Ctxt, Sub0) + false -> opt_simple_let_1(Let, Arg, Ctxt, Sub) end. opt_simple_let_1(#c_let{vars=Vs0,body=B0}=Let, Arg0, Ctxt, Sub0) -> %% Optimise let and add new substitutions. - {Vs,Args,Sub1} = let_substs(Vs0, Arg0, Sub0), - BodySub = case {Vs,Args} of - {[V],[A]} -> - case is_bool_expr(A, Sub0) of - true -> - update_types(V, [#c_literal{val=true}], Sub1); - false -> - Sub1 - end; - {_,_} -> Sub1 - end, - B = body(B0, Ctxt, BodySub), - Arg = core_lib:make_values(Args), - opt_simple_let_2(Let, Vs, Arg, B, Ctxt, Sub1). - -opt_simple_let_2(Let0, Vs0, Arg0, Body0, effect, Sub) -> - case {Vs0,Arg0,Body0} of - {[],#c_values{es=[]},Body} -> - %% No variables left (because of substitutions). - Body; - {[_|_],Arg,#c_literal{}} -> - %% The body is a literal. That means that we can ignore - %% it and that the return value is Arg revisited in - %% effect context. - body(Arg, effect, sub_new_preserve_types(Sub)); - {Vs,Arg,Body} -> - %% Since we are in effect context, there is a chance - %% that the body no longer references the variables. - %% In that case we can construct a sequence and visit - %% that in effect context: - %% let <Var> = Arg in BodyWithoutVar ==> seq Arg BodyWithoutVar - case is_any_var_used(Vs, Body) of - false -> - expr(#c_seq{arg=Arg,body=Body}, effect, sub_new_preserve_types(Sub)); - true -> - Let = Let0#c_let{vars=Vs,arg=Arg,body=Body}, - opt_case_in_let_arg(opt_case_in_let(Let, Sub), effect, Sub) - end - end; -opt_simple_let_2(Let, Vs0, Arg0, Body, value, Sub) -> + {Vs1,Args,Sub1} = let_substs(Vs0, Arg0, Sub0), + BodySub = update_let_types(Vs1, Args, Sub1), + B1 = body(B0, Ctxt, BodySub), + Arg1 = core_lib:make_values(Args), + {Vs,Arg,B} = opt_not_in_let(Vs1, Arg1, B1), + opt_simple_let_2(Let, Vs, Arg, B, B0, Ctxt, Sub1). + +opt_simple_let_2(Let0, Vs0, Arg0, Body, PrevBody, Ctxt, Sub) -> case {Vs0,Arg0,Body} of - {[#c_var{name=N1}],Arg,#c_var{name=N2}} -> + {[#c_var{name=N1}],Arg1,#c_var{name=N2}} -> case N1 =:= N2 of true -> %% let <Var> = Arg in <Var> ==> Arg - Arg; + Arg1; false -> %% let <Var> = Arg in <OtherVar> ==> seq Arg OtherVar - expr(#c_seq{arg=Arg,body=Body}, value, sub_new_preserve_types(Sub)) + Arg = maybe_suppress_warnings(Arg1, Vs0, PrevBody), + expr(#c_seq{arg=Arg,body=Body}, Ctxt, + sub_new_preserve_types(Sub)) end; {[],#c_values{es=[]},_} -> %% No variables left. Body; - {_,Arg,#c_literal{}} -> - %% The variable is not used in the body. The argument - %% can be evaluated in effect context to simplify it. - expr(#c_seq{arg=Arg,body=Body}, value, sub_new_preserve_types(Sub)); - {Vs,Arg,Body} -> - opt_case_in_let_arg( - opt_case_in_let(Let#c_let{vars=Vs,arg=Arg,body=Body}, Sub), - value, Sub) + {Vs,Arg1,#c_literal{}} -> + Arg = maybe_suppress_warnings(Arg1, Vs, PrevBody), + E = case Ctxt of + effect -> + %% Throw away the literal body. + Arg; + value -> + %% Since the variable is not used in the body, we + %% can rewrite the let to a sequence. + %% let <Var> = Arg in Literal ==> seq Arg Literal + #c_seq{arg=Arg,body=Body} + end, + expr(E, Ctxt, sub_new_preserve_types(Sub)); + {Vs,Arg1,Body} -> + %% If none of the variables are used in the body, we can + %% rewrite the let to a sequence: + %% let <Var> = Arg in BodyWithoutVar ==> + %% seq Arg BodyWithoutVar + case is_any_var_used(Vs, Body) of + false -> + Arg = maybe_suppress_warnings(Arg1, Vs, PrevBody), + expr(#c_seq{arg=Arg,body=Body}, Ctxt, + sub_new_preserve_types(Sub)); + true -> + Let1 = Let0#c_let{vars=Vs,arg=Arg1,body=Body}, + Let2 = opt_bool_case_in_let(Let1, Sub), + opt_case_in_let_arg(Let2, Ctxt, Sub) + end end. +%% maybe_suppress_warnings(Arg, [#c_var{}], PreviousBody) -> Arg' +%% Try to suppress false warnings when a variable is not used. +%% For instance, we don't expect a warning for useless building in: +%% +%% R = #r{}, %No warning expected. +%% R#r.f %Optimization would remove the reference to R. +%% +%% To avoid false warnings, we will check whether the variables were +%% referenced in the original unoptimized code. If they were, we will +%% consider the warning false and suppress it. + +maybe_suppress_warnings(Arg, Vs, PrevBody) -> + case should_suppress_warning(Arg) of + true -> + Arg; %Already suppressed. + false -> + case is_any_var_used(Vs, PrevBody) of + true -> + suppress_warning([Arg]); + false -> + Arg + end + end. + +%% Suppress warnings for a Core Erlang expression whose value will +%% be ignored. +suppress_warning([H|T]) -> + case cerl:is_literal(H) of + true -> + suppress_warning(T); + false -> + case cerl:is_data(H) of + true -> + suppress_warning(cerl:data_es(H) ++ T); + false -> + %% Some other thing, such as a function call. + %% This cannot be the compiler's fault, so the + %% warning should not be suppressed. We must + %% be careful not to destroy tail-recursion. + case T of + [] -> + H; + [_|_] -> + cerl:c_seq(H, suppress_warning(T)) + end + end + end; +suppress_warning([]) -> void(). + move_case_into_arg(#c_case{arg=#c_let{vars=OuterVars0,arg=OuterArg, body=InnerArg0}=Outer, clauses=InnerClauses}=Inner, Sub) -> @@ -2682,7 +2594,7 @@ move_case_into_arg(#c_case{arg=#c_let{vars=OuterVars0,arg=OuterArg, %% let <OuterVars> = <OuterArg> %% in case <InnerArg> of <InnerClauses> end %% - ScopeSub0 = sub_subst_scope(Sub#sub{t=[]}), + ScopeSub0 = sub_subst_scope(Sub#sub{t=#{}}), {OuterVars,ScopeSub} = pattern_list(OuterVars0, ScopeSub0), InnerArg = body(InnerArg0, ScopeSub), Outer#c_let{vars=OuterVars,arg=OuterArg, @@ -2711,7 +2623,7 @@ move_case_into_arg(#c_case{arg=#c_case{arg=OuterArg, %% <OuterCb> %% end %% - ScopeSub0 = sub_subst_scope(Sub#sub{t=[]}), + ScopeSub0 = sub_subst_scope(Sub#sub{t=#{}}), {OuterPats,ScopeSub} = pattern_list(OuterPats0, ScopeSub0), OuterGuard = guard(OuterGuard0, ScopeSub), InnerArg = body(InnerArg0, ScopeSub), @@ -2756,7 +2668,7 @@ move_case_into_arg(_, _) -> %% <> when 'true' -> %% let <Var> = Literal2 in LetBody %% end -%% +%% %% In the worst case, the size of the code could increase. %% In practice, though, substituting the literals into %% LetBody and doing constant folding will decrease the code @@ -2789,14 +2701,114 @@ is_any_var_used([#c_var{name=V}|Vs], Expr) -> end; is_any_var_used([], _) -> false. -is_boolean_type(V, #sub{t=Tdb}) -> - case orddict:find(V, Tdb) of - {ok,bool} -> true; - _ -> false +%%% +%%% Retrieving information about types. +%%% + +-spec get_type(cerl:cerl(), #sub{}) -> type_info() | 'none'. + +get_type(#c_var{name=V}, #sub{t=Tdb}) -> + case Tdb of + #{V:=Type} -> Type; + _ -> none + end; +get_type(C, _) -> + case cerl:type(C) of + binary -> C; + map -> C; + _ -> + case cerl:is_data(C) of + true -> C; + false -> none + end + end. + +-spec is_boolean_type(cerl:cerl(), sub()) -> yes_no_maybe(). + +is_boolean_type(Var, Sub) -> + case get_type(Var, Sub) of + none -> + maybe; + bool -> + yes; + C -> + B = cerl:is_c_atom(C) andalso + is_boolean(cerl:atom_val(C)), + yes_no(B) + end. + +-spec is_int_type(cerl:cerl(), sub()) -> yes_no_maybe(). + +is_int_type(Var, Sub) -> + case get_type(Var, Sub) of + none -> maybe; + integer -> yes; + C -> yes_no(cerl:is_c_int(C)) + end. + +-spec is_tuple_type(cerl:cerl(), sub()) -> yes_no_maybe(). + +is_tuple_type(Var, Sub) -> + case get_type(Var, Sub) of + none -> maybe; + C -> yes_no(cerl:is_c_tuple(C)) end. +yes_no(true) -> yes; +yes_no(false) -> no. + +%%% +%%% Update type information. +%%% + +update_let_types(Vs, Args, Sub) when is_list(Args) -> + update_let_types_1(Vs, Args, Sub); +update_let_types(_Vs, _Arg, Sub) -> + %% The argument is a complex expression (such as a 'case') + %% that returns multiple values. + Sub. + +update_let_types_1([#c_var{}=V|Vs], [A|As], Sub0) -> + Sub = update_types_from_expr(V, A, Sub0), + update_let_types_1(Vs, As, Sub); +update_let_types_1([], [], Sub) -> Sub. + +update_types_from_expr(V, Expr, Sub) -> + Type = extract_type(Expr, Sub), + update_types(V, [Type], Sub). + +extract_type(#c_call{module=#c_literal{val=erlang}, + name=#c_literal{val=Name}, + args=Args}=Call, Sub) -> + case returns_integer(Name, Args) of + true -> integer; + false -> extract_type_1(Call, Sub) + end; +extract_type(Expr, Sub) -> + extract_type_1(Expr, Sub). + +extract_type_1(Expr, Sub) -> + case is_bool_expr(Expr, Sub) of + false -> Expr; + true -> bool + end. + +returns_integer(bit_size, [_]) -> true; +returns_integer('bsl', [_,_]) -> true; +returns_integer('bsr', [_,_]) -> true; +returns_integer(byte_size, [_]) -> true; +returns_integer(length, [_]) -> true; +returns_integer('rem', [_,_]) -> true; +returns_integer(size, [_]) -> true; +returns_integer(tuple_size, [_]) -> true; +returns_integer(trunc, [_]) -> true; +returns_integer(_, _) -> false. + %% update_types(Expr, Pattern, Sub) -> Sub' %% Update the type database. + +-spec update_types(cerl:cerl(), [type_info()], sub()) -> sub(). + update_types(Expr, Pat, #sub{t=Tdb0}=Sub) -> Tdb = update_types_1(Expr, Pat, Tdb0), Sub#sub{t=Tdb}. @@ -2813,33 +2825,38 @@ update_types_1(#c_var{name=V,anno=Anno}, Pat, Types) -> update_types_1(_, _, Types) -> Types. update_types_2(V, [#c_tuple{}=P], Types) -> - orddict:store(V, P, Types); + Types#{V=>P}; update_types_2(V, [#c_literal{val=Bool}], Types) when is_boolean(Bool) -> - orddict:store(V, bool, Types); + Types#{V=>bool}; +update_types_2(V, [Type], Types) when is_atom(Type) -> + Types#{V=>Type}; update_types_2(_, _, Types) -> Types. %% kill_types(V, Tdb) -> Tdb' %% Kill any entries that references the variable, %% either in the key or in the value. -kill_types(V, [{V,_}|Tdb]) -> - kill_types(V, Tdb); -kill_types(V, [{_,#c_tuple{}=Tuple}=Entry|Tdb]) -> +kill_types(V, Tdb) -> + maps:from_list(kill_types2(V,maps:to_list(Tdb))). + +kill_types2(V, [{V,_}|Tdb]) -> + kill_types2(V, Tdb); +kill_types2(V, [{_,#c_tuple{}=Tuple}=Entry|Tdb]) -> case core_lib:is_var_used(V, Tuple) of - false -> [Entry|kill_types(V, Tdb)]; - true -> kill_types(V, Tdb) + false -> [Entry|kill_types2(V, Tdb)]; + true -> kill_types2(V, Tdb) end; -kill_types(V, [{_,Atom}=Entry|Tdb]) when is_atom(Atom) -> - [Entry|kill_types(V, Tdb)]; -kill_types(_, []) -> []. +kill_types2(V, [{_,Atom}=Entry|Tdb]) when is_atom(Atom) -> + [Entry|kill_types2(V, Tdb)]; +kill_types2(_, []) -> []. %% copy_type(DestVar, SrcVar, Tdb) -> Tdb' %% If the SrcVar has a type, assign it to DestVar. %% copy_type(V, #c_var{name=Src}, Tdb) -> - case orddict:find(Src, Tdb) of - {ok,Type} -> orddict:store(V, Type, Tdb); - error -> Tdb + case Tdb of + #{Src:=Type} -> Tdb#{V=>Type}; + _ -> Tdb end; copy_type(_, _, Tdb) -> Tdb. @@ -3074,15 +3091,15 @@ bsm_ensure_no_partition_2([#c_var{name=V}|Ps], N, G, Vstate, S) -> bsm_ensure_no_partition_2([_|Ps], N, G, _, S) -> bsm_ensure_no_partition_2(Ps, N-1, G, bin_argument_order, S). -bsm_ensure_no_partition_after([#c_clause{pats=Ps}|Cs], Pos) -> +bsm_ensure_no_partition_after([#c_clause{pats=Ps}=C|Cs], Pos) -> case nth(Pos, Ps) of #c_var{} -> bsm_ensure_no_partition_after(Cs, Pos); - P -> - bsm_problem(P, bin_partition) + _ -> + bsm_problem(C, bin_partition) end; bsm_ensure_no_partition_after([], _) -> ok. - + bsm_could_match_binary(#c_alias{pat=P}) -> bsm_could_match_binary(P); bsm_could_match_binary(#c_cons{}) -> false; bsm_could_match_binary(#c_tuple{}) -> false; @@ -3116,11 +3133,11 @@ add_bin_opt_info(Core, Term) -> end. add_warning(Core, Term) -> - case is_compiler_generated(Core) of + case should_suppress_warning(Core) of true -> ok; false -> - Anno = core_lib:get_anno(Core), + Anno = cerl:get_ann(Core), Line = get_line(Anno), File = get_file(Anno), Key = {?MODULE,warnings}, @@ -3141,9 +3158,17 @@ get_file([{file,File}|_]) -> File; get_file([_|T]) -> get_file(T); get_file([]) -> "no_file". % should not happen +should_suppress_warning(Core) -> + is_compiler_generated(Core) orelse + is_result_unwanted(Core). + is_compiler_generated(Core) -> - Anno = core_lib:get_anno(Core), - member(compiler_generated, Anno). + Ann = cerl:get_ann(Core), + member(compiler_generated, Ann). + +is_result_unwanted(Core) -> + Ann = cerl:get_ann(Core), + member(result_not_wanted, Ann). get_warnings() -> ordsets:from_list((erase({?MODULE,warnings}))). @@ -3235,12 +3260,12 @@ format_error(bin_var_used_in_guard) -> verify_scope(E, #sub{s=Scope}) -> Free0 = cerl_trees:free_variables(E), Free = [V || V <- Free0, not is_tuple(V)], %Ignore function names. - case ordsets:is_subset(Free, gb_sets:to_list(Scope)) of + case ordsets:is_subset(Free, cerl_sets:to_list(Scope)) of true -> true; false -> io:format("~p\n", [E]), io:format("~p\n", [Free]), - io:format("~p\n", [gb_sets:to_list(Scope)]), + io:format("~p\n", [cerl_sets:to_list(Scope)]), false end. -endif. |