From fccac1598cc13fcd9a3d7e85e2c4cae722f1bfc4 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Tue, 4 Jun 2019 12:52:34 +0200 Subject: Create a shared wrapper function for all occurrences of 'fun F/A' If the `fun F/A` syntax is used multiple times with the same `F/A`, (for examle, `fun foo/2`), there would a wrapper function and fun entry generated for each occurrence. Using the new support in the OTP 23 runtime system, generate a single wrapper function and fun entry for each `F/A`. Since there is only one wrapper function, it can be named based on the name of the function it calls to faciliate debugging, not based on the function that defines the fun. For example, the wrapper function for `fun foo/0` will now be named `-fun.foo/0-'. --- lib/compiler/src/v3_kernel.erl | 63 +++++++++++++++++++++++++++++++----------- 1 file changed, 47 insertions(+), 16 deletions(-) (limited to 'lib/compiler/src/v3_kernel.erl') diff --git a/lib/compiler/src/v3_kernel.erl b/lib/compiler/src/v3_kernel.erl index e2b8787224..6fd1790c1a 100644 --- a/lib/compiler/src/v3_kernel.erl +++ b/lib/compiler/src/v3_kernel.erl @@ -81,8 +81,11 @@ -export([module/2,format_error/1]). --import(lists, [map/2,foldl/3,foldr/3,mapfoldl/3,splitwith/2,member/2, - keyfind/3,partition/2,droplast/1,last/1,sort/1,reverse/1]). +-import(lists, [droplast/1,flatten/1,foldl/3,foldr/3, + map/2,mapfoldl/3,member/2, + keyfind/3,keyreplace/4, + last/1,partition/2,reverse/1, + splitwith/2,sort/1]). -import(ordsets, [add_element/2,del_element/2,union/2,union/1,subtract/2]). -import(cerl, [c_tuple/1]). @@ -120,15 +123,19 @@ copy_anno(Kdst, Ksrc) -> funs=[], %Fun functions free=#{}, %Free variables ws=[] :: [warning()], %Warnings. - guard_refc=0}). %> 0 means in guard + guard_refc=0, %> 0 means in guard + no_shared_fun_wrappers=false :: boolean() + }). -spec module(cerl:c_module(), [compile:option()]) -> {'ok', #k_mdef{}, [warning()]}. -module(#c_module{anno=A,name=M,exports=Es,attrs=As,defs=Fs}, _Options) -> +module(#c_module{anno=A,name=M,exports=Es,attrs=As,defs=Fs}, Options) -> Kas = attributes(As), Kes = map(fun (#c_var{name={_,_}=Fname}) -> Fname end, Es), - St0 = #kern{}, + NoSharedFunWrappers = proplists:get_bool(no_shared_fun_wrappers, + Options), + St0 = #kern{no_shared_fun_wrappers=NoSharedFunWrappers}, {Kfs,St} = mapfoldl(fun function/2, St0, Fs), {ok,#k_mdef{anno=A,name=M#c_literal.val,exports=Kes,attributes=Kas, body=Kfs ++ St#kern.funs},lists:sort(St#kern.ws)}. @@ -716,16 +723,27 @@ gexpr_test_add(Ke, St0) -> %% expr(Cexpr, Sub, State) -> {Kexpr,[PreKexpr],State}. %% Convert a Core expression, flattening it at the same time. -expr(#c_var{anno=A,name={_Name,Arity}}=Fname, Sub, St) -> - %% A local in an expression. - %% For now, these are wrapped into a fun by reverse - %% eta-conversion, but really, there should be exactly one - %% such "lambda function" for each escaping local name, - %% instead of one for each occurrence as done now. +expr(#c_var{anno=A0,name={Name,Arity}}=Fname, Sub, St) -> Vs = [#c_var{name=list_to_atom("V" ++ integer_to_list(V))} || - V <- integers(1, Arity)], - Fun = #c_fun{anno=A,vars=Vs,body=#c_apply{anno=A,op=Fname,args=Vs}}, - expr(Fun, Sub, St); + V <- integers(1, Arity)], + case St#kern.no_shared_fun_wrappers of + false -> + %% Generate a (possibly shared) wrapper function for calling + %% this function. + Wrapper0 = ["-fun.",atom_to_list(Name),"/",integer_to_list(Arity),"-"], + Wrapper = list_to_atom(flatten(Wrapper0)), + Id = {id,{0,0,Wrapper}}, + A = keyreplace(id, 1, A0, Id), + Fun = #c_fun{anno=A,vars=Vs,body=#c_apply{anno=A,op=Fname,args=Vs}}, + expr(Fun, Sub, St); + true -> + %% For backward compatibility with OTP 22 and earlier, + %% use the pre-generated name for the fun wrapper. + %% There will be one wrapper function for each occurrence + %% of `fun F/A`. + Fun = #c_fun{anno=A0,vars=Vs,body=#c_apply{anno=A0,op=Fname,args=Vs}}, + expr(Fun, Sub, St) + end; expr(#c_var{anno=A,name=V}, Sub, St) -> {#k_var{anno=A,name=get_vsub(V, Sub)},[],St}; expr(#c_literal{anno=A,val=V}, _Sub, St) -> @@ -2446,8 +2464,21 @@ uexpr(Lit, {break,Rs0}, St0) -> {#k_put{anno=#k{us=Used,ns=lit_list_vars(Rs),a=get_kanno(Lit)}, arg=Lit,ret=Rs},Used,St1}. -add_local_function(_, #kern{funs=ignore}=St) -> St; -add_local_function(F, #kern{funs=Funs}=St) -> St#kern{funs=[F|Funs]}. +add_local_function(_, #kern{funs=ignore}=St) -> + St; +add_local_function(#k_fdef{func=Name,arity=Arity}=F, #kern{funs=Funs}=St) -> + case is_defined(Name, Arity, Funs) of + false -> + St#kern{funs=[F|Funs]}; + true -> + St + end. + +is_defined(Name, Arity, [#k_fdef{func=Name,arity=Arity}|_]) -> + true; +is_defined(Name, Arity, [#k_fdef{}|T]) -> + is_defined(Name, Arity, T); +is_defined(_, _, []) -> false. %% Make a #k_fdef{}, making sure that the body is always a #k_match{}. make_fdef(Anno, Name, Arity, Vs, #k_match{}=Body) -> -- cgit v1.2.3