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-rw-r--r--lib/compiler/src/sys_core_fold.erl210
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) ->
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-28 05:48:20 +0000