diff options
Diffstat (limited to 'lib/compiler/src')
| -rw-r--r-- | lib/compiler/src/sys_core_fold.erl | 210 |
1 files changed, 179 insertions, 31 deletions
diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl index e134a37f22..ab67c8164b 100644 --- a/lib/compiler/src/sys_core_fold.erl +++ b/lib/compiler/src/sys_core_fold.erl @@ -1078,8 +1078,17 @@ is_atom_or_var(_) -> false. %% clause(Clause, Cepxr, Context, Sub) -> Clause. -clause(#c_clause{pats=Ps0,guard=G0,body=B0}=Cl, Cexpr, Ctxt, Sub0) -> - {Ps1,Sub1} = pattern_list(Ps0, Sub0), +clause(#c_clause{pats=Ps0}=Cl, Cexpr, Ctxt, Sub0) -> + try pattern_list(Ps0, Sub0) of + {Ps1,Sub1} -> + clause_1(Cl, Ps1, Cexpr, Ctxt, Sub1) + catch + nomatch -> + Cl#c_clause{anno=[compiler_generated], + guard=#c_literal{val=false}} + end. + +clause_1(#c_clause{guard=G0,body=B0}=Cl, Ps1, Cexpr, Ctxt, Sub1) -> Sub2 = update_types(Cexpr, Ps1, Sub1), GSub = case {Cexpr,Ps1,G0} of {_,_,#c_literal{}} -> @@ -1210,14 +1219,16 @@ bin_pattern_list(Ps0, Isub, Osub0) -> {Ps,{_,Osub}} = mapfoldl(fun bin_pattern/2, {Isub,Osub0}, Ps0), {Ps,Osub}. -bin_pattern(#c_bitstr{val=E0,size=Size0}=Pat, {Isub0,Osub0}) -> +bin_pattern(#c_bitstr{val=E0,size=Size0}=Pat0, {Isub0,Osub0}) -> Size1 = expr(Size0, Isub0), {E1,Osub} = pattern(E0, Isub0, Osub0), Isub = case E0 of #c_var{} -> sub_set_var(E0, E1, Isub0); _ -> Isub0 end, - {Pat#c_bitstr{val=E1,size=Size1},{Isub,Osub}}. + Pat = Pat0#c_bitstr{val=E1,size=Size1}, + bin_pat_warn(Pat), + {Pat,{Isub,Osub}}. pattern_list(Ps, Sub) -> pattern_list(Ps, Sub, Sub). @@ -1234,6 +1245,106 @@ var_list(Vs, Sub0) -> end, Sub0, Vs). +%%% +%%% Generate warnings for binary patterns that will not match. +%%% + +bin_pat_warn(#c_bitstr{type=#c_literal{val=Type}, + val=Val0, + size=#c_literal{val=Sz}, + unit=#c_literal{val=Unit}, + flags=Fl}=Pat) -> + case {Type,Sz} of + {_,_} when is_integer(Sz), Sz >= 0 -> ok; + {binary,all} -> ok; + {utf8,undefined} -> ok; + {utf16,undefined} -> ok; + {utf32,undefined} -> ok; + {_,_} -> + add_warning(Pat, {nomatch_bit_syntax_size,Sz}), + throw(nomatch) + end, + case {Type,Val0} of + {integer,#c_literal{val=Val}} when is_integer(Val) -> + Signedness = signedness(Fl), + TotalSz = Sz * Unit, + bit_pat_warn_int(Val, TotalSz, Signedness, Pat); + {float,#c_literal{val=Val}} when is_float(Val) -> + ok; + {utf8,#c_literal{val=Val}} when is_integer(Val) -> + bit_pat_warn_unicode(Val, Pat); + {utf16,#c_literal{val=Val}} when is_integer(Val) -> + bit_pat_warn_unicode(Val, Pat); + {utf32,#c_literal{val=Val}} when is_integer(Val) -> + bit_pat_warn_unicode(Val, Pat); + {_,#c_literal{val=Val}} -> + add_warning(Pat, {nomatch_bit_syntax_type,Val,Type}), + throw(nomatch); + {_,_} -> + ok + end; +bin_pat_warn(#c_bitstr{type=#c_literal{val=Type},val=Val0,flags=Fl}=Pat) -> + %% Size is variable. Not much that we can check. + case {Type,Val0} of + {integer,#c_literal{val=Val}} when is_integer(Val) -> + case signedness(Fl) of + unsigned when Val < 0 -> + add_warning(Pat, {nomatch_bit_syntax_unsigned,Val}), + throw(nomatch); + _ -> + ok + end; + {float,#c_literal{val=Val}} when is_float(Val) -> + ok; + {_,#c_literal{val=Val}} -> + add_warning(Pat, {nomatch_bit_syntax_type,Val,Type}), + throw(nomatch); + {_,_} -> + ok + end. + +bit_pat_warn_int(Val, 0, signed, Pat) -> + if + Val =:= 0 -> + ok; + true -> + add_warning(Pat, {nomatch_bit_syntax_truncated,signed,Val,0}), + throw(nomatch) + end; +bit_pat_warn_int(Val, Sz, signed, Pat) -> + if + Val < 0, Val bsr (Sz - 1) =/= -1 -> + add_warning(Pat, {nomatch_bit_syntax_truncated,signed,Val,Sz}), + throw(nomatch); + Val > 0, Val bsr (Sz - 1) =/= 0 -> + add_warning(Pat, {nomatch_bit_syntax_truncated,signed,Val,Sz}), + throw(nomatch); + true -> + ok + end; +bit_pat_warn_int(Val, _Sz, unsigned, Pat) when Val < 0 -> + add_warning(Pat, {nomatch_bit_syntax_unsigned,Val}), + throw(nomatch); +bit_pat_warn_int(Val, Sz, unsigned, Pat) -> + if + Val bsr Sz =:= 0 -> + ok; + true -> + add_warning(Pat, {nomatch_bit_syntax_truncated,unsigned,Val,Sz}), + throw(nomatch) + end. + +bit_pat_warn_unicode(U, _Pat) when 0 =< U, U =< 16#10FFFF -> + ok; +bit_pat_warn_unicode(U, Pat) -> + add_warning(Pat, {nomatch_bit_syntax_unicode,U}), + throw(nomatch). + +signedness(#c_literal{val=Flags}) -> + [S] = [F || F <- Flags, F =:= signed orelse F =:= unsigned], + S. + + %% is_subst(Expr) -> true | false. %% Test whether an expression is a suitable substitution. @@ -2285,39 +2396,49 @@ move_let_into_expr(#c_let{vars=Lvs0,body=Lbody0}=Let, case {TwoClauses,is_failing_clause(Ca0),is_failing_clause(Cb0)} of {true,false,true} -> %% let <Lvars> = case <Case-expr> of - %% <Cvars> -> <Clause-body>; - %% <OtherCvars> -> erlang:error(...) + %% <Cpats> -> <Clause-body>; + %% <OtherCpats> -> erlang:error(...) %% end %% in <Let-body> %% %% ==> %% %% case <Case-expr> of - %% <Cvars> -> + %% <Cpats> -> %% let <Lvars> = <Clause-body> %% in <Let-body>; - %% <OtherCvars> -> erlang:error(...) + %% <OtherCpats> -> erlang:error(...) %% end Cexpr = body(Cexpr0, Sub0), - CaVars0 = Ca0#c_clause.pats, + CaPats0 = Ca0#c_clause.pats, G0 = Ca0#c_clause.guard, B0 = Ca0#c_clause.body, 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=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}, - - Ca = Ca0#c_clause{pats=CaVars,guard=G,body=B}, - Cb = clause(Cb0, Cexpr, value, Sub0), - Case#c_case{arg=Cexpr,clauses=[Ca,Cb]}; + try pattern_list(CaPats0, ScopeSub0) of + {CaPats,ScopeSub} -> + G = guard(G0, ScopeSub), + + B1 = body(B0, ScopeSub), + + {Lvs,B2,Sub1} = let_substs(Lvs0, B1, Sub0), + 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}, + + Ca = Ca0#c_clause{pats=CaPats,guard=G,body=B}, + Cb = clause(Cb0, Cexpr, value, Sub0), + Case#c_case{arg=Cexpr,clauses=[Ca,Cb]} + catch + nomatch -> + %% This is not a defeat. The code will eventually + %% be optimized to erlang:error(...) by the other + %% optimizations done in this module. + impossible + end; {_,_,_} -> impossible end; move_let_into_expr(#c_let{vars=Lvs0,body=Lbody0}=Let, @@ -2638,14 +2759,18 @@ move_case_into_arg(#c_case{arg=#c_case{arg=OuterArg, %% end %% ScopeSub0 = sub_subst_scope(Sub#sub{t=#{}}), - {OuterPats,ScopeSub} = pattern_list(OuterPats0, ScopeSub0), - OuterGuard = guard(OuterGuard0, ScopeSub), - InnerArg = body(InnerArg0, ScopeSub), - Inner = Inner0#c_case{arg=InnerArg,clauses=InnerClauses}, - OuterCa = OuterCa0#c_clause{pats=OuterPats,guard=OuterGuard, - body=Inner}, - Outer#c_case{arg=OuterArg, - clauses=[OuterCa,OuterCb]}; + + %% We KNOW that pattern_list/2 has already been called for OuterPats0; + %% therefore, it cannot throw an exception. + {OuterPats,ScopeSub} = pattern_list(OuterPats0, ScopeSub0), + OuterGuard = guard(OuterGuard0, ScopeSub), + InnerArg = body(InnerArg0, ScopeSub), + Inner = Inner0#c_case{arg=InnerArg,clauses=InnerClauses}, + OuterCa = OuterCa0#c_clause{pats=OuterPats, + guard=OuterGuard, + body=Inner}, + Outer#c_case{arg=OuterArg, + clauses=[OuterCa,OuterCb]}; false -> impossible end; @@ -3227,6 +3352,29 @@ format_error(nomatch_shadow) -> "this clause cannot match because a previous clause always matches"; format_error(nomatch_guard) -> "the guard for this clause evaluates to 'false'"; +format_error({nomatch_bit_syntax_truncated,Signess,Val,Sz}) -> + S = case Signess of + signed -> "a 'signed'"; + unsigned -> "an 'unsigned'" + end, + F = "this clause cannot match because the value ~P" + " will not fit in ~s binary segment of size ~p", + flatten(io_lib:format(F, [Val,10,S,Sz])); +format_error({nomatch_bit_syntax_unsigned,Val}) -> + F = "this clause cannot match because the negative value ~P" + " will never match the value of an 'unsigned' binary segment", + flatten(io_lib:format(F, [Val,10])); +format_error({nomatch_bit_syntax_size,Sz}) -> + F = "this clause cannot match because '~P' is not a valid size for a binary segment", + flatten(io_lib:format(F, [Sz,10])); +format_error({nomatch_bit_syntax_type,Val,Type}) -> + F = "this clause cannot match because '~P' is not of the" + " expected type '~p'", + flatten(io_lib:format(F, [Val,10,Type])); +format_error({nomatch_bit_syntax_unicode,Val}) -> + F = "this clause cannot match because the value ~p" + " is not a valid Unicode code point", + flatten(io_lib:format(F, [Val])); format_error(no_clause_match) -> "no clause will ever match"; format_error(nomatch_clause_type) -> |