From 40a96ab9a41b780d59da643cce71084e72901a54 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Tue, 15 Feb 2011 07:34:08 +0100 Subject: sys_core_fold: Be careful to preserve annotations while optimizing --- lib/compiler/src/sys_core_fold.erl | 183 ++++++++++++++++++++----------------- 1 file changed, 99 insertions(+), 84 deletions(-) (limited to 'lib') diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl index 96015fbe58..c870bb68c8 100644 --- a/lib/compiler/src/sys_core_fold.erl +++ b/lib/compiler/src/sys_core_fold.erl @@ -460,7 +460,8 @@ eval_binary(#c_binary{anno=Anno,segments=Ss}=Bin) -> Bin; throw:{badarg,Warning} -> add_warning(Bin, Warning), - #c_call{module=#c_literal{val=erlang}, + #c_call{anno=Anno, + module=#c_literal{val=erlang}, name=#c_literal{val=error}, args=[#c_literal{val=badarg}]} end. @@ -658,36 +659,34 @@ call_0(Call, M, N, As0, Sub) -> %% We inline some very common higher order list operations. %% We use the same evaluation order as the library function. -call_1(_Call, lists, all, [Arg1,Arg2], Sub) -> +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{op=Loop, args=[Xs]}}, + 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=#c_primop{name=#c_literal{val='match_fail'}, - args=[Err1]}}, + 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{op=F, args=[X]}, + 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_literal{val=true}, body=#c_literal{val=true}}, Err2 = #c_tuple{es=[#c_literal{val='function_clause'}, Xs]}, C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=#c_primop{name=#c_literal{val='match_fail'}, - args=[Err2]}}, + body=match_fail(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{op=Loop, args=[L]}}}, + body=#c_apply{anno=Anno, op=Loop, args=[L]}}}, Sub); -call_1(_Call, lists, any, [Arg1,Arg2], 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'}, @@ -696,72 +695,71 @@ call_1(_Call, lists, any, [Arg1,Arg2], Sub) -> 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{op=Loop, args=[Xs]}}, + body=#c_apply{anno=Anno, op=Loop, args=[Xs]}}, CC3 = #c_clause{pats=[X], guard=#c_literal{val=true}, - body=#c_primop{name=#c_literal{val='match_fail'}, - args=[Err1]}}, + 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{op=F, args=[X]}, + 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_literal{val=true}, body=#c_literal{val=false}}, Err2 = #c_tuple{es=[#c_literal{val='function_clause'}, Xs]}, C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=#c_primop{name=#c_literal{val='match_fail'}, - args=[Err2]}}, + body=match_fail(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{op=Loop, args=[L]}}}, + body=#c_apply{anno=Anno, op=Loop, args=[L]}}}, Sub); -call_1(_Call, lists, foreach, [Arg1,Arg2], 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{op=F, args=[X]}, - body=#c_apply{op=Loop, args=[Xs]}}}, + 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_literal{val=true}, body=#c_literal{val=ok}}, Err = #c_tuple{es=[#c_literal{val='function_clause'}, Xs]}, C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=#c_primop{name=#c_literal{val='match_fail'}, - args=[Err]}}, + body=match_fail(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{op=Loop, args=[L]}}}, + body=#c_apply{anno=Anno, op=Loop, args=[L]}}}, Sub); -call_1(_Call, lists, map, [Arg1,Arg2], 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{op=F, args=[X]}, + body=#c_let{vars=[H], arg=#c_apply{anno=Anno, + op=F, + args=[X]}, body=#c_cons{hd=H, - tl=#c_apply{op=Loop, + tl=#c_apply{anno=Anno, + op=Loop, args=[Xs]}}}}, C2 = #c_clause{pats=[#c_literal{val=[]}], guard=#c_literal{val=true}, body=#c_literal{val=[]}}, Err = #c_tuple{es=[#c_literal{val='function_clause'}, Xs]}, C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=#c_primop{name=#c_literal{val='match_fail'}, - args=[Err]}}, + body=match_fail(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{op=Loop, args=[L]}}}, + body=#c_apply{anno=Anno, op=Loop, args=[L]}}}, Sub); -call_1(_Call, lists, flatmap, [Arg1,Arg2], 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'}, @@ -769,26 +767,27 @@ call_1(_Call, lists, flatmap, [Arg1,Arg2], Sub) -> 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{op=F, args=[X]}, - body=#c_call{module=#c_literal{val=erlang}, + arg=#c_apply{anno=Anno, op=F, args=[X]}, + body=#c_call{anno=Anno, + module=#c_literal{val=erlang}, name=#c_literal{val='++'}, args=[H, - #c_apply{op=Loop, + #c_apply{anno=Anno, + op=Loop, args=[Xs]}]}}}, C2 = #c_clause{pats=[#c_literal{val=[]}], guard=#c_literal{val=true}, body=#c_literal{val=[]}}, Err = #c_tuple{es=[#c_literal{val='function_clause'}, Xs]}, C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=#c_primop{name=#c_literal{val='match_fail'}, - args=[Err]}}, + body=match_fail(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{op=Loop, args=[L]}}}, + body=#c_apply{anno=Anno, op=Loop, args=[L]}}}, Sub); -call_1(_Call, lists, filter, [Arg1,Arg2], 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'}, @@ -800,72 +799,75 @@ call_1(_Call, lists, filter, [Arg1,Arg2], Sub) -> 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=#c_primop{name=#c_literal{val='match_fail'}, - args=[Err1]}}, + 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{op=F, args=[X]}, + arg=#c_apply{anno=Anno, op=F, args=[X]}, body=#c_let{vars=[Xs], - arg=#c_apply{op=Loop, + arg=#c_apply{anno=Anno, + op=Loop, args=[Xs]}, body=Case}}}, C2 = #c_clause{pats=[#c_literal{val=[]}], guard=#c_literal{val=true}, body=#c_literal{val=[]}}, Err2 = #c_tuple{es=[#c_literal{val='function_clause'}, Xs]}, C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=#c_primop{name=#c_literal{val='match_fail'}, - args=[Err2]}}, + body=match_fail(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{op=Loop, args=[L]}}}, + body=#c_apply{anno=Anno, op=Loop, args=[L]}}}, Sub); -call_1(_Call, lists, foldl, [Arg1,Arg2,Arg3], 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{op=Loop, - args=[Xs, #c_apply{op=F, args=[X, A]}]}}, + 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_literal{val=true}, body=A}, Err = #c_tuple{es=[#c_literal{val='function_clause'}, Xs]}, C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=#c_primop{name=#c_literal{val='match_fail'}, - args=[Err]}}, + body=match_fail(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{op=Loop, args=[L, A]}}}, + body=#c_apply{anno=Anno, op=Loop, args=[L, A]}}}, Sub); -call_1(_Call, lists, foldr, [Arg1,Arg2,Arg3], 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{op=F, args=[X, #c_apply{op=Loop, - args=[Xs, A]}]}}, + 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_literal{val=true}, body=A}, Err = #c_tuple{es=[#c_literal{val='function_clause'}, Xs]}, C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=#c_primop{name=#c_literal{val='match_fail'}, - args=[Err]}}, + body=match_fail(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{op=Loop, args=[L, A]}}}, + body=#c_apply{anno=Anno, op=Loop, args=[L, A]}}}, Sub); -call_1(_Call, lists, mapfoldl, [Arg1,Arg2,Arg3], 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'}, @@ -876,15 +878,16 @@ call_1(_Call, lists, mapfoldl, [Arg1,Arg2,Arg3], Sub) -> 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=#c_primop{name=#c_literal{val='match_fail'}, - args=[Err]}}, + 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{op=F, args=[X, Avar]}, + body=Match(#c_apply{anno=Anno, op=F, args=[X, Avar]}, #c_tuple{es=[X, Avar]}, %%% Tuple passing version - Match(#c_apply{op=Loop, args=[Xs, Avar]}, + Match(#c_apply{anno=Anno, + op=Loop, + args=[Xs, Avar]}, #c_tuple{es=[Xs, Avar]}, #c_tuple{es=[#c_cons{hd=X, tl=Xs}, Avar]}) %%% Multiple-value version @@ -902,22 +905,23 @@ call_1(_Call, lists, mapfoldl, [Arg1,Arg2,Arg3], Sub) -> %%% body=#c_values{es=[#c_literal{val=[]}, A]}}, Err = #c_tuple{es=[#c_literal{val='function_clause'}, Xs]}, C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=#c_primop{name=#c_literal{val='match_fail'}, - args=[Err]}}, + body=match_fail(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{op=Loop, args=[L, Avar]}}}, + 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(_Call, lists, mapfoldr, [Arg1,Arg2,Arg3], 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'}, @@ -928,15 +932,16 @@ call_1(_Call, lists, mapfoldr, [Arg1,Arg2,Arg3], Sub) -> 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=#c_primop{name=#c_literal{val='match_fail'}, - args=[Err]}}, + 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{op=Loop, args=[Xs, Avar]}, + body=Match(#c_apply{anno=Anno, + op=Loop, + args=[Xs, Avar]}, #c_tuple{es=[Xs, Avar]}, - Match(#c_apply{op=F, args=[X, Avar]}, + Match(#c_apply{anno=Anno, op=F, args=[X, Avar]}, #c_tuple{es=[X, Avar]}, #c_tuple{es=[#c_cons{hd=X, tl=Xs}, Avar]})) %%% Multiple-value version @@ -955,15 +960,16 @@ call_1(_Call, lists, mapfoldr, [Arg1,Arg2,Arg3], Sub) -> %%% body=#c_values{es=[#c_literal{val=[]}, A]}}, Err = #c_tuple{es=[#c_literal{val='function_clause'}, Xs]}, C3 = #c_clause{pats=[Xs], guard=#c_literal{val=true}, - body=#c_primop{name=#c_literal{val='match_fail'}, - args=[Err]}}, + body=match_fail(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{op=Loop, args=[L, Avar]}}}, + body=#c_apply{anno=Anno, + op=Loop, + args=[L, Avar]}}}, %%% Multiple-value version %%% body=#c_let{vars=[Xs, A], %%% arg=#c_apply{op=Loop, @@ -973,6 +979,11 @@ call_1(_Call, lists, mapfoldr, [Arg1,Arg2,Arg3], 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 @@ -1280,9 +1291,9 @@ eval_setelement_2(Pos, [H|T], NewVal) when Pos > 1 -> %% eval_failure(Call, Reason) -> add_warning(Call, {eval_failure,Reason}), - #c_call{module=#c_literal{val=erlang}, - name=#c_literal{val=error}, - args=[#c_literal{val=Reason}]}. + Call#c_call{module=#c_literal{val=erlang}, + name=#c_literal{val=error}, + args=[#c_literal{val=Reason}]}. %% simplify_apply(Call0, Mod, Func, Args) -> Call %% Simplify an apply/3 to a call if the number of arguments @@ -1742,23 +1753,24 @@ opt_bool_clauses([_|_], _, _) -> opt_bool_not(#c_case{arg=Arg,clauses=Cs0}=Case0) -> case Arg of - #c_call{module=#c_literal{val=erlang}, + #c_call{anno=Anno,module=#c_literal{val=erlang}, name=#c_literal{val='not'}, args=[Expr]} -> - Cs = opt_bool_not(Expr, Cs0), + Cs = opt_bool_not(Anno, Expr, Cs0), Case = Case0#c_case{arg=Expr,clauses=Cs}, opt_bool_not(Case); _ -> opt_bool_case_redundant(Case0) end. -opt_bool_not(Expr, Cs) -> +opt_bool_not(Anno, Expr, Cs) -> Tail = case is_bool_expr(Expr) of false -> [#c_clause{anno=[compiler_generated], pats=[#c_var{name=cor_variable}], guard=#c_literal{val=true}, - body=#c_call{module=#c_literal{val=erlang}, + body=#c_call{anno=Anno, + module=#c_literal{val=erlang}, name=#c_literal{val=error}, args=[#c_literal{val=badarg}]}}]; true -> [] @@ -1957,13 +1969,16 @@ case_tuple_pat([#c_tuple{es=Ps}], Arity) when length(Ps) =:= Arity -> case_tuple_pat([#c_literal{val=T}], Arity) when tuple_size(T) =:= Arity -> Ps = [#c_literal{val=E} || E <- tuple_to_list(T)], {ok,Ps,[]}; -case_tuple_pat([#c_var{anno=A}=V], Arity) -> - Vars = make_vars(A, 1, Arity), - {ok,Vars,[{V,#c_tuple{es=Vars}}]}; +case_tuple_pat([#c_var{anno=Anno}=V], Arity) -> + Vars = make_vars(Anno, 1, Arity), + {ok,Vars,[{V,#c_tuple{anno=Anno,es=Vars}}]}; case_tuple_pat([#c_alias{var=V,pat=P}], Arity) -> case case_tuple_pat([P], Arity) of - {ok,Ps,Avs} -> {ok,Ps,[{V,#c_tuple{es=unalias_pat_list(Ps)}}|Avs]}; - error -> error + {ok,Ps,Avs} -> + Anno = core_lib:get_anno(P), + {ok,Ps,[{V,#c_tuple{anno=Anno,es=unalias_pat_list(Ps)}}|Avs]}; + error -> + error end; case_tuple_pat(_, _) -> error. -- cgit v1.2.3 From c6b0d6dce5709c61e549e850c2615fd288e27ba9 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Tue, 15 Mar 2011 07:55:44 +0100 Subject: sys_core_fold: Eliminate incorrect warning The compiler (sys_core_fold) tries to avoid constructing tuples in case expressions. The following code: c(A, B) -> case {A,B} of {ok,X} -> X; {_,_} -> error end. will be rewritten so that no tuple is built. If a clause requires a tuple to be built as in this code: c(A, B) -> case {A,B} of {ok,X} -> X; V -> V %The tuple will be built here end. the tuple will be built in the clause(s) in which it is needed. If the value returned from the case is not used as in this code: c(A, B) -> case {A,B} of V -> V %Warning: a term is constructed, but never used end, ok. there will be an incorrect warning. Basically, what happens is that the code is reduced to: c(A, B) -> {A,B}, %Warning: a term is constructed, but never used ok. and the optimizer sees that the {A,B} tuple can't possibly be used. Eliminate the warning by adding a 'compiler_generated' annotation to the tuple. Reported-by: Kostis Sagonas --- lib/compiler/src/sys_core_fold.erl | 15 ++++++++++++--- lib/compiler/test/warnings_SUITE.erl | 10 ++++++++++ 2 files changed, 22 insertions(+), 3 deletions(-) (limited to 'lib') diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl index c870bb68c8..9360556e00 100644 --- a/lib/compiler/src/sys_core_fold.erl +++ b/lib/compiler/src/sys_core_fold.erl @@ -1969,13 +1969,22 @@ case_tuple_pat([#c_tuple{es=Ps}], Arity) when length(Ps) =:= Arity -> case_tuple_pat([#c_literal{val=T}], Arity) when tuple_size(T) =:= Arity -> Ps = [#c_literal{val=E} || E <- tuple_to_list(T)], {ok,Ps,[]}; -case_tuple_pat([#c_var{anno=Anno}=V], Arity) -> - Vars = make_vars(Anno, 1, Arity), +case_tuple_pat([#c_var{anno=Anno0}=V], Arity) -> + Vars = make_vars(Anno0, 1, Arity), + + %% 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 tuple as + %% compiler generated. + + Anno = [compiler_generated|Anno0], {ok,Vars,[{V,#c_tuple{anno=Anno,es=Vars}}]}; case_tuple_pat([#c_alias{var=V,pat=P}], Arity) -> case case_tuple_pat([P], Arity) of {ok,Ps,Avs} -> - Anno = core_lib:get_anno(P), + Anno0 = core_lib:get_anno(P), + Anno = [compiler_generated|Anno0], {ok,Ps,[{V,#c_tuple{anno=Anno,es=unalias_pat_list(Ps)}}|Avs]}; error -> error diff --git a/lib/compiler/test/warnings_SUITE.erl b/lib/compiler/test/warnings_SUITE.erl index 8cc3ca4199..dd18a6e1a3 100644 --- a/lib/compiler/test/warnings_SUITE.erl +++ b/lib/compiler/test/warnings_SUITE.erl @@ -453,6 +453,16 @@ effect(Config) when is_list(Config) -> true -> ok end, ok. + + m8(A, B) -> + case {A,B} of + V -> V + end, + ok. + + m9(Bs) -> + [{B,ok} = {B,foo:bar(B)} || B <- Bs], + ok. ">>, [], {warnings,[{5,sys_core_fold,{no_effect,{erlang,is_integer,1}}}, -- cgit v1.2.3