From 3142041ade649cfb783b4c1a52ee67cd2d2212f9 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Wed, 22 Sep 2010 10:35:42 +0200 Subject: Factor out some of the code for binary generators In the code for handling binary generators (in list and binary comprehensions), factor out the code for appending a match-all tail segment onto a pattern into a separate function. That will only make the code somewhat simpler, but will facilitate fixing a bug/misfeture in the next commit. --- lib/compiler/src/v3_core.erl | 68 +++++++++++++++++++++++++------------------- 1 file changed, 38 insertions(+), 30 deletions(-) (limited to 'lib/compiler/src') diff --git a/lib/compiler/src/v3_core.erl b/lib/compiler/src/v3_core.erl index f6bb45787c..3f33dbca52 100644 --- a/lib/compiler/src/v3_core.erl +++ b/lib/compiler/src/v3_core.erl @@ -892,25 +892,22 @@ lc_tq(Line, E, [{generate,Lg,P,G}|Qs0], Mc, St0) -> lc_tq(Line, E, [{b_generate,Lg,P,G}|Qs0], Mc, St0) -> {Gs,Qs1} = splitwith(fun is_guard_test/1, Qs0), {Name,St1} = new_fun_name("blc", St0), - {Tname,St2} = new_var_name(St1), - LA = lineno_anno(Line, St2), + LA = lineno_anno(Line, St1), LAnno = #a{anno=LA}, - HeadBinPattern = pattern(P,St2), - #c_binary{segments=Ps} = HeadBinPattern, - {EPs,St3} = emasculate_segments(Ps,St2), - Tail = #c_var{anno=LA,name=Tname}, - TailSegment = #c_bitstr{val=Tail,size=#c_literal{val=all}, - unit=#c_literal{val=1}, - type=#c_literal{val=binary}, - flags=#c_literal{val=[big,unsigned]}}, - Pattern = HeadBinPattern#c_binary{segments=Ps ++ [TailSegment]}, - EPattern = HeadBinPattern#c_binary{segments=EPs ++ [TailSegment]}, + HeadBinPattern = pattern(P, St1), + #c_binary{segments=Ps0} = HeadBinPattern, + {Ps,Tail,St2} = append_tail_segment(Ps0, St1), + {EPs,St3} = emasculate_segments(Ps, St2), + Pattern = HeadBinPattern#c_binary{segments=Ps}, + EPattern = HeadBinPattern#c_binary{segments=EPs}, {Arg,St4} = new_var(St3), {Guardc,St5} = lc_guard_tests(Gs, St4), %These are always flat! + Tname = Tail#c_var.name, {Nc,[],St6} = expr({call,Lg,{atom,Lg,Name},[{var,Lg,Tname}]}, St5), {Bc,Bps,St7} = lc_tq(Line, E, Qs1, Nc, St6), {Gc,Gps,St10} = safe(G, St7), %Will be a function argument! Fc = function_clause([Arg], LA, {Name,1}), + {TailSegList,_,St} = append_tail_segment([], St10), Cs = [#iclause{anno=#a{anno=[compiler_generated|LA]}, pats=[Pattern], guard=Guardc, @@ -922,14 +919,14 @@ lc_tq(Line, E, [{b_generate,Lg,P,G}|Qs0], Mc, St0) -> op=#c_var{anno=LA,name={Name,1}}, args=[Tail]}]}, #iclause{anno=LAnno, - pats=[#c_binary{anno=LA, segments=[TailSegment]}],guard=[], + pats=[#c_binary{anno=LA,segments=TailSegList}],guard=[], body=[Mc]}], Fun = #ifun{anno=LAnno,id=[],vars=[Arg],clauses=Cs,fc=Fc}, {#iletrec{anno=LAnno,defs=[{{Name,1},Fun}], body=Gps ++ [#iapply{anno=LAnno, op=#c_var{anno=LA,name={Name,1}}, args=[Gc]}]}, - [],St10}; + [],St}; lc_tq(Line, E, [Fil0|Qs0], Mc, St0) -> %% Special case sequences guard tests. LA = lineno_anno(Line, St0), @@ -1037,26 +1034,24 @@ bc_tq1(Line, E, [{b_generate,Lg,P,G}|Qs0], AccExpr, St0) -> {Gs,Qs1} = splitwith(fun is_guard_test/1, Qs0), {Name,St1} = new_fun_name("lbc", St0), LA = lineno_anno(Line, St1), - {[Tail,AccVar],St2} = new_vars(LA, 2, St1), + {AccVar,St2} = new_var(LA, St1), LAnno = #a{anno=LA}, HeadBinPattern = pattern(P, St2), - #c_binary{segments=Ps} = HeadBinPattern, - {EPs,St3} = emasculate_segments(Ps, St2), - TailSegment = #c_bitstr{val=Tail,size=#c_literal{val=all}, - unit=#c_literal{val=1}, - type=#c_literal{val=binary}, - flags=#c_literal{val=[big,unsigned]}}, - Pattern = HeadBinPattern#c_binary{segments=Ps ++ [TailSegment]}, - EPattern = HeadBinPattern#c_binary{segments=EPs ++ [TailSegment]}, - {Arg,St4} = new_var(St3), + #c_binary{segments=Ps0} = HeadBinPattern, + {Ps,Tail,St3} = append_tail_segment(Ps0, St2), + {EPs,St4} = emasculate_segments(Ps, St3), + Pattern = HeadBinPattern#c_binary{segments=Ps}, + EPattern = HeadBinPattern#c_binary{segments=EPs}, + {Arg,St5} = new_var(St4), NewMore = {call,Lg,{atom,Lg,Name},[{var,Lg,Tail#c_var.name}, {var,Lg,AccVar#c_var.name}]}, - {Guardc,St5} = lc_guard_tests(Gs, St4), %These are always flat! - {Bc,Bps,St6} = bc_tq1(Line, E, Qs1, AccVar, St5), - {Nc,Nps,St7} = expr(NewMore, St6), - {Gc,Gps,St8} = safe(G, St7), %Will be a function argument! + {Guardc,St6} = lc_guard_tests(Gs, St5), %These are always flat! + {Bc,Bps,St7} = bc_tq1(Line, E, Qs1, AccVar, St6), + {Nc,Nps,St8} = expr(NewMore, St7), + {Gc,Gps,St9} = safe(G, St8), %Will be a function argument! Fc = function_clause([Arg,AccVar], LA, {Name,2}), Body = Bps ++ Nps ++ [#iset{var=AccVar,arg=Bc},Nc], + {TailSegList,_,St} = append_tail_segment([], St9), Cs = [#iclause{anno=LAnno, pats=[Pattern,AccVar], guard=Guardc, @@ -1066,7 +1061,7 @@ bc_tq1(Line, E, [{b_generate,Lg,P,G}|Qs0], AccExpr, St0) -> guard=[], body=Nps ++ [Nc]}, #iclause{anno=LAnno, - pats=[#c_binary{anno=LA,segments=[TailSegment]},AccVar], + pats=[#c_binary{anno=LA,segments=TailSegList},AccVar], guard=[], body=[AccVar]}], Fun = #ifun{anno=LAnno,id=[],vars=[Arg,AccVar],clauses=Cs,fc=Fc}, @@ -1074,7 +1069,7 @@ bc_tq1(Line, E, [{b_generate,Lg,P,G}|Qs0], AccExpr, St0) -> body=Gps ++ [#iapply{anno=LAnno, op=#c_var{anno=LA,name={Name,2}}, args=[Gc,AccExpr]}]}, - [],St8}; + [],St}; bc_tq1(Line, E, [Fil0|Qs0], AccVar, St0) -> %% Special case sequences guard tests. LA = lineno_anno(Line, St0), @@ -1120,6 +1115,19 @@ bc_tq1(_, {bin,Bl,Elements}, [], AccVar, St0) -> %%Anno = Anno0#a{anno=[compiler_generated|A]}, {set_anno(E, Anno),Pre,St}. +append_tail_segment(Segs, St) -> + app_tail_seg(Segs, St, []). + +app_tail_seg([H|T], St, Acc) -> + app_tail_seg(T, St, [H|Acc]); +app_tail_seg([], St0, Acc) -> + {Var,St} = new_var(St0), + Tail = #c_bitstr{val=Var,size=#c_literal{val=all}, + unit=#c_literal{val=1}, + type=#c_literal{val=binary}, + flags=#c_literal{val=[unsigned,big]}}, + {reverse(Acc, [Tail]),Var,St}. + emasculate_segments(Segs, St) -> emasculate_segments(Segs, St, []). -- cgit v1.2.3 From 5daa0013177545446b26cdba0dbd167f0e040d63 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Wed, 22 Sep 2010 11:09:57 +0200 Subject: Don't generate multiple tail segments in binary matching In binary matching, there must only be one "tail segment" (i.e. a size-less segment of type binary) and it must be last. Thus, the compiler will reject the following function definition: foo(<>) -> ok. But code such as the following: [42 || <<_:8/integer, _/bits>> <= Bits] will internally (in the Core Erlang format) be translated to a binary matching pattern containing two tail segments. The compiler happens to generate correct code anyway (later passes will get rid of the redundant tail segment), but it is ugly and will confuse tools such as Dialyzer. Change the transformation of binary generators (in both list and binary comprehensions) not to generate add a tail segment if there already is one. --- lib/compiler/src/v3_core.erl | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'lib/compiler/src') diff --git a/lib/compiler/src/v3_core.erl b/lib/compiler/src/v3_core.erl index 3f33dbca52..2da24b2908 100644 --- a/lib/compiler/src/v3_core.erl +++ b/lib/compiler/src/v3_core.erl @@ -1118,6 +1118,16 @@ bc_tq1(_, {bin,Bl,Elements}, [], AccVar, St0) -> append_tail_segment(Segs, St) -> app_tail_seg(Segs, St, []). +app_tail_seg([#c_bitstr{val=Var0,size=#c_literal{val=all}}=Seg0]=L, + St0, Acc) -> + case Var0 of + #c_var{name='_'} -> + {Var,St} = new_var(St0), + Seg = Seg0#c_bitstr{val=Var}, + {reverse(Acc, [Seg]),Var,St}; + #c_var{} -> + {reverse(Acc, L),Var0,St0} + end; app_tail_seg([H|T], St, Acc) -> app_tail_seg(T, St, [H|Acc]); app_tail_seg([], St0, Acc) -> -- cgit v1.2.3 From 7b283aa9507b45f2cd403b061ad92ab059fb71b5 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Wed, 22 Sep 2010 14:08:45 +0200 Subject: core_lint: Enforce that tail segments only occur at the end --- lib/compiler/src/core_lint.erl | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) (limited to 'lib/compiler/src') diff --git a/lib/compiler/src/core_lint.erl b/lib/compiler/src/core_lint.erl index b633f568c9..097577b371 100644 --- a/lib/compiler/src/core_lint.erl +++ b/lib/compiler/src/core_lint.erl @@ -1,7 +1,7 @@ %% %% %CopyrightBegin% %% -%% Copyright Ericsson AB 1999-2009. All Rights Reserved. +%% Copyright Ericsson AB 1999-2010. 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 @@ -116,7 +116,9 @@ format_error({duplicate_var,N,{F,A}}) -> format_error({unbound_var,N,{F,A}}) -> io_lib:format("unbound variable ~s in ~w/~w", [N,F,A]); format_error({undefined_function,{F1,A1},{F2,A2}}) -> - io_lib:format("undefined function ~w/~w in ~w/~w", [F1,A1,F2,A2]). + io_lib:format("undefined function ~w/~w in ~w/~w", [F1,A1,F2,A2]); +format_error({tail_segment_not_at_end,{F,A}}) -> + io_lib:format("binary tail segment not at end in ~w/~w", [F,A]). -type ret() :: {'ok', [{module(), [warning(),...]}]} | {'error', [{module(), [error(),...]}], @@ -450,7 +452,8 @@ pattern(#c_cons{hd=H,tl=T}, Def, Ps, St) -> pattern_list([H,T], Def, Ps, St); pattern(#c_tuple{es=Es}, Def, Ps, St) -> pattern_list(Es, Def, Ps, St); -pattern(#c_binary{segments=Ss}, Def, Ps, St) -> +pattern(#c_binary{segments=Ss}, Def, Ps, St0) -> + St = pat_bin_tail_check(Ss, St0), pat_bin(Ss, Def, Ps, St); pattern(#c_alias{var=V,pat=P}, Def, Ps, St0) -> {Vvs,St1} = variable(V, Ps, St0), @@ -482,6 +485,19 @@ pat_segment(#c_bitstr{val=V,size=S,type=T}, Def0, Ps0, St0) -> pat_segment(_, Def, Ps, St) -> {Ps,Def,add_error({not_bs_pattern,St#lint.func}, St)}. +%% pat_bin_tail_check([Elem], State) -> State. +%% There must be at most one tail segment (a size-less segment of +%% type binary) and it must occur at the end. + +pat_bin_tail_check([#c_bitstr{size=#c_literal{val=all}}], St) -> + %% Size-less field is OK at the end of the list of segments. + St; +pat_bin_tail_check([#c_bitstr{size=#c_literal{val=all}}|_], St) -> + add_error({tail_segment_not_at_end,St#lint.func}, St); +pat_bin_tail_check([_|Ss], St) -> + pat_bin_tail_check(Ss, St); +pat_bin_tail_check([], St) -> St. + %% pat_bit_expr(SizePat, Type, Defined, State) -> State. %% Check the Size pattern, this is an input! Because of optimizations, %% we must allow any kind of constant and literal here. -- cgit v1.2.3