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Diffstat (limited to 'lib/compiler/src/sys_core_dsetel.erl')
-rw-r--r-- | lib/compiler/src/sys_core_dsetel.erl | 360 |
1 files changed, 0 insertions, 360 deletions
diff --git a/lib/compiler/src/sys_core_dsetel.erl b/lib/compiler/src/sys_core_dsetel.erl deleted file mode 100644 index 9ab83c210f..0000000000 --- a/lib/compiler/src/sys_core_dsetel.erl +++ /dev/null @@ -1,360 +0,0 @@ -%% -%% %CopyrightBegin% -%% -%% Copyright Ericsson AB 2002-2018. 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% -%% -%% Purpose : Using dsetelement to make multiple-field record updates -%% faster. - -%% The expansion of record field updates, when more than one field is -%% updated, but not a majority of the fields, will create a sequence of -%% calls to 'erlang:setelement(Index, Value, Tuple)' where Tuple in the -%% first call is the original record tuple, and in the subsequent calls -%% Tuple is the result of the previous call. Furthermore, all Index -%% values are constant positive integers, and the first call to -%% 'setelement' will have the greatest index. Thus all the following -%% calls do not actually need to test at run-time whether Tuple has type -%% tuple, nor that the index is within the tuple bounds. -%% -%% Since this introduces destructive updates in the Core Erlang code, it -%% must be done as a last stage before going to lower-level code. -%% -%% NOTE: Because there are currently no write barriers in the system, -%% this kind of optimization can only be done when we are sure that -%% garbage collection will not be triggered between the creation of the -%% tuple and the destructive updates - otherwise we might insert -%% pointers from an older generation to a newer. -%% -%% The rewriting is done as follows: -%% -%% let X1 = call 'erlang':'setelement(5, Tuple, Value1) -%% in call 'erlang':'setelement(3, X1, Value2) -%% => -%% let X1 = call 'erlang':'setelement(5, Tuple, Value1) -%% in do primop dsetelement(3, X1, Value2) -%% X1 -%% and -%% let X1 = call 'erlang':'setelement(5, Tuple, Value1) -%% in let X2 = call 'erlang':'setelement(3, X1, Value2) -%% in ... -%% => -%% let X2 = call 'erlang':'setelement(5, Tuple, Value1) -%% in do primop 'dsetelement(3, X2, Value2) -%% ... -%% if X1 is used exactly once. -%% Thus, we need to track variable usage. -%% - --module(sys_core_dsetel). - --export([module/2]). - --include("core_parse.hrl"). - --spec module(cerl:c_module(), [compile:option()]) -> {'ok', cerl:c_module()}. - -module(M0, _Options) -> - M = visit_module(M0), - {ok,M}. - -visit_module(#c_module{defs=Ds0}=R) -> - Env = #{}, - Ds = visit_module_1(Ds0, Env, []), - R#c_module{defs=Ds}. - -visit_module_1([{Name,F0}|Fs], Env, Acc) -> - try visit(Env, F0) of - {F,_} -> - visit_module_1(Fs, Env, [{Name,F}|Acc]) - catch - Class:Error:Stack -> - #c_var{name={Func,Arity}} = Name, - io:fwrite("Function: ~w/~w\n", [Func,Arity]), - erlang:raise(Class, Error, Stack) - end; -visit_module_1([], _, Acc) -> - lists:reverse(Acc). - -visit(Env, #c_var{name={_,_}}=R) -> - %% Ignore local function name. - {R, Env}; -visit(Env0, #c_var{name=X}=R) -> - %% There should not be any free variables. If there are, - %% the case will fail with an exception. - case Env0 of - #{X:=N} -> - {R, Env0#{X:=N+1}} - end; -visit(Env, #c_literal{}=R) -> - {R, Env}; -visit(Env0, #c_tuple{es=Es0}=R) -> - {Es1,Env1} = visit_list(Env0, Es0), - {R#c_tuple{es=Es1}, Env1}; -visit(Env0, #c_map{es=Es0}=R) -> - {Es1,Env1} = visit_list(Env0, Es0), - {R#c_map{es=Es1}, Env1}; -visit(Env0, #c_map_pair{key=K0,val=V0}=R) -> - {K,Env1} = visit(Env0, K0), - {V,Env2} = visit(Env1, V0), - {R#c_map_pair{key=K,val=V}, Env2}; -visit(Env0, #c_cons{hd=H0,tl=T0}=R) -> - {H1,Env1} = visit(Env0, H0), - {T1,Env2} = visit(Env1, T0), - {R#c_cons{hd=H1,tl=T1}, Env2}; -visit(Env0, #c_binary{segments=Segs}=R) -> - Env = visit_bin_segs(Env0, Segs), - {R, Env}; -visit(Env0, #c_values{es=Es0}=R) -> - {Es1,Env1} = visit_list(Env0, Es0), - {R#c_values{es=Es1}, Env1}; -visit(Env0, #c_fun{vars=Vs, body=B0}=R) -> - {Xs, Env1} = bind_vars(Vs, Env0), - {B1,Env2} = visit(Env1, B0), - {R#c_fun{body=B1}, restore_vars(Xs, Env0, Env2)}; -visit(Env0, #c_let{vars=Vs, arg=A0, body=B0}=R) -> - {A1,Env1} = visit(Env0, A0), - {Xs,Env2} = bind_vars(Vs, Env1), - {B1,Env3} = visit(Env2, B0), - rewrite(R#c_let{arg=A1,body=B1}, Env3, restore_vars(Xs, Env1, Env3)); -visit(Env0, #c_seq{arg=A0, body=B0}=R) -> - {A1,Env1} = visit(Env0, A0), - {B1,Env2} = visit(Env1, B0), - {R#c_seq{arg=A1,body=B1}, Env2}; -visit(Env0, #c_case{arg=A0,clauses=Cs0}=R) -> - {A1,Env1} = visit(Env0, A0), - {Cs1,Env2} = visit_list(Env1, Cs0), - {R#c_case{arg=A1,clauses=Cs1}, Env2}; -visit(Env0, #c_clause{pats=Ps,guard=G0,body=B0}=R) -> - {Vs, Env1} = visit_pats(Ps, Env0), - {G1,Env2} = visit(Env1, G0), - {B1,Env3} = visit(Env2, B0), - {R#c_clause{guard=G1,body=B1}, restore_vars(Vs, Env0, Env3)}; -visit(Env0, #c_receive{clauses=Cs0,timeout=T0,action=A0}=R) -> - {T1,Env1} = visit(Env0, T0), - {Cs1,Env2} = visit_list(Env1, Cs0), - {A1,Env3} = visit(Env2, A0), - {R#c_receive{clauses=Cs1,timeout=T1,action=A1}, Env3}; -visit(Env0, #c_apply{op=Op0, args=As0}=R) -> - {Op1,Env1} = visit(Env0, Op0), - {As1,Env2} = visit_list(Env1, As0), - {R#c_apply{op=Op1,args=As1}, Env2}; -visit(Env0, #c_call{module=M0,name=N0,args=As0}=R) -> - {M1,Env1} = visit(Env0, M0), - {N1,Env2} = visit(Env1, N0), - {As1,Env3} = visit_list(Env2, As0), - {R#c_call{module=M1,name=N1,args=As1}, Env3}; -visit(Env0, #c_primop{name=N0, args=As0}=R) -> - {N1,Env1} = visit(Env0, N0), - {As1,Env2} = visit_list(Env1, As0), - {R#c_primop{name=N1,args=As1}, Env2}; -visit(Env0, #c_try{arg=E0, vars=Vs, body=B0, evars=Evs, handler=H0}=R) -> - {E1,Env1} = visit(Env0, E0), - {Xs, Env2} = bind_vars(Vs, Env1), - {B1,Env3} = visit(Env2, B0), - Env4 = restore_vars(Xs, Env1, Env3), - {Ys, Env5} = bind_vars(Evs, Env4), - {H1,Env6} = visit(Env5, H0), - {R#c_try{arg=E1,body=B1,handler=H1}, restore_vars(Ys, Env4, Env6)}; -visit(Env0, #c_catch{body=B0}=R) -> - {B1,Env1} = visit(Env0, B0), - {R#c_catch{body=B1}, Env1}; -visit(Env0, #c_letrec{defs=Ds0,body=B0}=R) -> - {Xs, Env1} = bind_vars([V || {V,_} <- Ds0], Env0), - {Ds1,Env2} = visit_def_list(Env1, Ds0), - {B1,Env3} = visit(Env2, B0), - {R#c_letrec{defs=Ds1,body=B1}, restore_vars(Xs, Env0, Env3)}. -%% The following general code for handling modules is slow if a module -%% contains very many functions. There is special code in visit_module/1 -%% which is much faster. -%% visit(Env0, #c_module{defs=D0}=R) -> -%% {R1,Env1} = visit(Env0, #c_letrec{defs=D0,body=#c_nil{}}), -%% {R#c_module{defs=R1#c_letrec.defs}, Env1}; - -visit_list(Env, L) -> - lists:mapfoldl(fun (E, A) -> visit(A, E) end, Env, L). - -visit_def_list(Env, L) -> - lists:mapfoldl(fun ({Name,V0}, E0) -> - {V1,E1} = visit(E0, V0), - {{Name,V1}, E1} - end, Env, L). - -visit_bin_segs(Env, Segs) -> - lists:foldl(fun (#c_bitstr{val=Val,size=Sz}, E0) -> - {_, E1} = visit(E0, Val), - {_, E2} = visit(E1, Sz), - E2 - end, Env, Segs). - -bind_vars(Vs, Env) -> - bind_vars(Vs, Env, []). - -bind_vars([#c_var{name=X}|Vs], Env0, Xs)-> - bind_vars(Vs, Env0#{X=>0}, [X|Xs]); -bind_vars([], Env,Xs) -> - {Xs, Env}. - -visit_pats(Ps, Env) -> - visit_pats(Ps, Env, []). - -visit_pats([P|Ps], Env0, Vs0) -> - {Vs1, Env1} = visit_pat(Env0, P, Vs0), - visit_pats(Ps, Env1, Vs1); -visit_pats([], Env, Vs) -> - {Vs, Env}. - -visit_pat(Env0, #c_var{name=V}, Vs) -> - {[V|Vs], Env0#{V=>0}}; -visit_pat(Env0, #c_tuple{es=Es}, Vs) -> - visit_pats(Es, Env0, Vs); -visit_pat(Env0, #c_map{es=Es}, Vs) -> - visit_pats(Es, Env0, Vs); -visit_pat(Env0, #c_map_pair{op=#c_literal{val=exact},key=V,val=K}, Vs0) -> - {Vs1, Env1} = visit_pat(Env0, V, Vs0), - visit_pat(Env1, K, Vs1); -visit_pat(Env0, #c_cons{hd=H,tl=T}, Vs0) -> - {Vs1, Env1} = visit_pat(Env0, H, Vs0), - visit_pat(Env1, T, Vs1); -visit_pat(Env0, #c_binary{segments=Segs}, Vs) -> - visit_pats(Segs, Env0, Vs); -visit_pat(Env0, #c_bitstr{val=Val,size=Sz}, Vs0) -> - {Vs1, Env1} = - case Sz of - #c_var{name=V} -> - %% We don't tolerate free variables. - case Env0 of - #{V:=N} -> - {Vs0, Env0#{V:=N+1}} - end; - _ -> - visit_pat(Env0, Sz, Vs0) - end, - visit_pat(Env1, Val, Vs1); -visit_pat(Env0, #c_alias{pat=P,var=#c_var{name=V}}, Vs) -> - visit_pat(Env0#{V=>0}, P, [V|Vs]); -visit_pat(Env, #c_literal{}, Vs) -> - {Vs, Env}. - -restore_vars([V|Vs], Env0, Env1) -> - case Env0 of - #{V:=N} -> - restore_vars(Vs, Env0, Env1#{V=>N}); - _ -> - restore_vars(Vs, Env0, maps:remove(V, Env1)) - end; -restore_vars([], _, Env1) -> - Env1. - - -%% let X1 = call 'erlang':'setelement(5, Tuple, Value1) -%% in call 'erlang':'setelement(3, X1, Value2) -%% => -%% let X1 = call 'erlang':'setelement(5, Tuple, Value1) -%% in do primop dsetelement(3, X1, Value2) -%% X1 - -rewrite(#c_let{vars=[#c_var{name=X}=V]=Vs, - arg=#c_call{module=#c_literal{val='erlang'}, - name=#c_literal{val='setelement'}, - args=[#c_literal{val=Index1}, _Tuple, _Val1] - }=A, - body=#c_call{anno=Banno,module=#c_literal{val='erlang'}, - name=#c_literal{val='setelement'}, - args=[#c_literal{val=Index2}, - #c_var{name=X}, - Val2] - } - }=R, - _BodyEnv, FinalEnv) - when is_integer(Index1), is_integer(Index2), Index2 > 0, Index1 > Index2 -> - case is_safe(Val2) of - true -> - {R#c_let{vars=Vs, - arg=A, - body=#c_seq{arg=#c_primop{ - anno=Banno, - name=#c_literal{val='dsetelement'}, - args=[#c_literal{val=Index2}, - V, - Val2]}, - body=V} - }, - FinalEnv}; - false -> - {R, FinalEnv} - end; - -%% let X1 = call 'erlang':'setelement(5, Tuple, Value1) -%% in let X2 = 'erlang':'setelement(3, X1, Value2) -%% in ... -%% => -%% let X2 = call 'erlang':'setelement(5, Tuple, Value1) -%% in do primop dsetelement(3, X2, Value2) -%% ... -%% if X1 is used exactly once. - -rewrite(#c_let{vars=[#c_var{name=X1}], - arg=#c_call{module=#c_literal{val='erlang'}, - name=#c_literal{val='setelement'}, - args=[#c_literal{val=Index1}, _Tuple, _Val1] - }=A, - body=#c_let{vars=[#c_var{}=V]=Vs, - arg=#c_call{anno=Banno, - module=#c_literal{val='erlang'}, - name=#c_literal{val='setelement'}, - args=[#c_literal{val=Index2}, - #c_var{name=X1}, - Val2]}, - body=B} - }=R, - BodyEnv, FinalEnv) - when is_integer(Index1), is_integer(Index2), Index2 > 0, Index1 > Index2 -> - case is_single_use(X1, BodyEnv) andalso is_safe(Val2) of - true -> - {R#c_let{vars=Vs, - arg=A, - body=#c_seq{arg=#c_primop{ - anno=Banno, - name=#c_literal{val='dsetelement'}, - args=[#c_literal{val=Index2}, - V, - Val2]}, - body=B} - }, - FinalEnv}; - false -> - {R, FinalEnv} - end; - -rewrite(R, _, FinalEnv) -> - {R, FinalEnv}. - -%% is_safe(CoreExpr) -> true|false -%% Determines whether the Core expression can cause a GC collection at run-time. -%% Note: Assumes that the constant pool is turned on. - -is_safe(#c_var{}) -> true; -is_safe(#c_literal{}) -> true; -is_safe(_) -> false. - -is_single_use(V, Env) -> - case Env of - #{V:=1} -> - true; - _ -> - false - end. |