aboutsummaryrefslogtreecommitdiffstats
path: root/lib/compiler/src/sys_core_fold.erl
diff options
context:
space:
mode:
Diffstat (limited to 'lib/compiler/src/sys_core_fold.erl')
-rw-r--r--lib/compiler/src/sys_core_fold.erl250
1 files changed, 209 insertions, 41 deletions
diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl
index 65699ccda9..ab67c8164b 100644
--- a/lib/compiler/src/sys_core_fold.erl
+++ b/lib/compiler/src/sys_core_fold.erl
@@ -277,7 +277,7 @@ expr(#c_fun{}=Fun, effect, _) ->
add_warning(Fun, useless_building),
void();
expr(#c_fun{vars=Vs0,body=B0}=Fun, Ctxt0, Sub0) ->
- {Vs1,Sub1} = pattern_list(Vs0, Sub0),
+ {Vs1,Sub1} = var_list(Vs0, Sub0),
Ctxt = case Ctxt0 of
{letrec,Ctxt1} -> Ctxt1;
value -> value
@@ -420,13 +420,13 @@ expr(#c_try{anno=A,arg=E0,vars=Vs0,body=B0,evars=Evs0,handler=H0}=Try, _, Sub0)
%% Here is the general try/catch construct outside of guards.
%% We can remove try if the value is simple and replace it with a let.
E1 = body(E0, value, Sub0),
- {Vs1,Sub1} = pattern_list(Vs0, Sub0),
+ {Vs1,Sub1} = var_list(Vs0, Sub0),
B1 = body(B0, value, Sub1),
case is_safe_simple(E1, Sub0) of
true ->
expr(#c_let{anno=A,vars=Vs1,arg=E1,body=B1}, value, Sub0);
false ->
- {Evs1,Sub2} = pattern_list(Evs0, Sub0),
+ {Evs1,Sub2} = var_list(Evs0, Sub0),
H1 = body(H0, value, Sub2),
Try#c_try{arg=E1,vars=Vs1,body=B1,evars=Evs1,handler=H1}
end.
@@ -1078,15 +1078,28 @@ 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} of
- {#c_var{name='_'},_} ->
+ GSub = case {Cexpr,Ps1,G0} of
+ {_,_,#c_literal{}} ->
+ %% No need for substitution tricks when the guard
+ %% does not contain any variables.
+ Sub2;
+ {#c_var{name='_'},_,_} ->
%% In a 'receive', Cexpr is the variable '_', which represents the
%% message being matched. We must NOT do any extra substiutions.
Sub2;
- {#c_var{},[#c_var{}=Var]} ->
+ {#c_var{},[#c_var{}=Var],_} ->
%% The idea here is to optimize expressions such as
%%
%% case A of A -> ...
@@ -1120,7 +1133,7 @@ clause(#c_clause{pats=Ps0,guard=G0,body=B0}=Cl, Cexpr, Ctxt, Sub0) ->
%% the unsubstituted variables and values.
let_substs(Vs0, As0, Sub0) ->
- {Vs1,Sub1} = pattern_list(Vs0, Sub0),
+ {Vs1,Sub1} = var_list(Vs0, Sub0),
{Vs2,As1,Ss} = let_substs_1(Vs1, As0, Sub1),
Sub2 = sub_add_scope([V || #c_var{name=V} <- Vs2], Sub1),
{Vs2,As1,
@@ -1206,20 +1219,132 @@ 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).
pattern_list(Ps0, Isub, Osub0) ->
mapfoldl(fun (P, Osub) -> pattern(P, Isub, Osub) end, Osub0, Ps0).
+%% var_list([Var], InSub) -> {Pattern,OutSub}.
+%% Works like pattern_list/2 but only accept variables and is
+%% guaranteed not to throw an exception.
+
+var_list(Vs, Sub0) ->
+ mapfoldl(fun (#c_var{}=V, Sub) ->
+ pattern(V, Sub, Sub)
+ 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.
@@ -2251,11 +2376,11 @@ move_let_into_expr(#c_let{vars=InnerVs0,body=InnerBody0}=Inner,
%%
Arg = body(Arg0, Sub0),
ScopeSub0 = sub_subst_scope(Sub0#sub{t=#{}}),
- {OuterVs,ScopeSub} = pattern_list(OuterVs0, ScopeSub0),
+ {OuterVs,ScopeSub} = var_list(OuterVs0, ScopeSub0),
OuterBody = body(OuterBody0, ScopeSub),
- {InnerVs,Sub} = pattern_list(InnerVs0, Sub0),
+ {InnerVs,Sub} = var_list(InnerVs0, Sub0),
InnerBody = body(InnerBody0, Sub),
Outer#c_let{vars=OuterVs,arg=Arg,
body=Inner#c_let{vars=InnerVs,arg=OuterBody,body=InnerBody}};
@@ -2271,39 +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,
@@ -2595,7 +2730,7 @@ move_case_into_arg(#c_case{arg=#c_let{vars=OuterVars0,arg=OuterArg,
%% in case <InnerArg> of <InnerClauses> end
%%
ScopeSub0 = sub_subst_scope(Sub#sub{t=#{}}),
- {OuterVars,ScopeSub} = pattern_list(OuterVars0, ScopeSub0),
+ {OuterVars,ScopeSub} = var_list(OuterVars0, ScopeSub0),
InnerArg = body(InnerArg0, ScopeSub),
Outer#c_let{vars=OuterVars,arg=OuterArg,
body=Inner#c_case{arg=InnerArg,clauses=InnerClauses}};
@@ -2624,14 +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;
@@ -2793,12 +2932,18 @@ extract_type_1(Expr, Sub) ->
true -> bool
end.
+returns_integer('band', [_,_]) -> true;
+returns_integer('bnot', [_]) -> true;
+returns_integer('bor', [_,_]) -> true;
+returns_integer('bxor', [_,_]) -> true;
returns_integer(bit_size, [_]) -> true;
returns_integer('bsl', [_,_]) -> true;
returns_integer('bsr', [_,_]) -> true;
returns_integer(byte_size, [_]) -> true;
+returns_integer('div', [_,_]) -> true;
returns_integer(length, [_]) -> true;
returns_integer('rem', [_,_]) -> true;
+returns_integer('round', [_]) -> true;
returns_integer(size, [_]) -> true;
returns_integer(tuple_size, [_]) -> true;
returns_integer(trunc, [_]) -> true;
@@ -3207,6 +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 2024-07-11 23:17:09 +0000