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-rw-r--r--lib/compiler/src/beam_validator.erl145
1 files changed, 119 insertions, 26 deletions
diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl
index c30ab34ac7..ee0011d397 100644
--- a/lib/compiler/src/beam_validator.erl
+++ b/lib/compiler/src/beam_validator.erl
@@ -29,7 +29,7 @@
-include("beam_disasm.hrl").
--import(lists, [reverse/1,foldl/3,foreach/2,dropwhile/2]).
+-import(lists, [any/2,dropwhile/2,foldl/3,foreach/2,reverse/1]).
%% To be called by the compiler.
@@ -365,7 +365,9 @@ valfun_1({recv_set,{f,Fail}}, Vst) when is_integer(Fail) ->
Vst;
%% Misc.
valfun_1(remove_message, Vst) ->
- Vst;
+ %% The message term is no longer fragile. It can be used
+ %% without restrictions.
+ remove_fragility(Vst);
valfun_1({'%',_}, Vst) ->
Vst;
valfun_1({line,_}, Vst) ->
@@ -533,7 +535,7 @@ valfun_4({bif,element,{f,Fail},[Pos,Tuple],Dst}, Vst0) ->
Vst1 = branch_state(Fail, Vst0),
TupleType = upgrade_tuple_type({tuple,[get_tuple_size(PosType)]}, TupleType0),
Vst = set_type(TupleType, Tuple, Vst1),
- set_type_reg(term, Dst, Vst);
+ set_type_reg(term, Tuple, Dst, Vst);
valfun_4({bif,raise,{f,0},Src,_Dst}, Vst) ->
validate_src(Src, Vst),
kill_state(Vst);
@@ -542,7 +544,8 @@ valfun_4(raw_raise=I, Vst) ->
valfun_4({bif,Op,{f,Fail},Src,Dst}, Vst0) ->
validate_src(Src, Vst0),
Vst = branch_state(Fail, Vst0),
- Type = bif_type(Op, Src, Vst),
+ Type0 = bif_type(Op, Src, Vst),
+ Type = propagate_fragility(Type0, Src, Vst),
set_type_reg(Type, Dst, Vst);
valfun_4({gc_bif,Op,{f,Fail},Live,Src,Dst}, #vst{current=St0}=Vst0) ->
verify_live(Live, Vst0),
@@ -552,7 +555,8 @@ valfun_4({gc_bif,Op,{f,Fail},Live,Src,Dst}, #vst{current=St0}=Vst0) ->
Vst2 = branch_state(Fail, Vst1),
Vst = prune_x_regs(Live, Vst2),
validate_src(Src, Vst),
- Type = bif_type(Op, Src, Vst),
+ Type0 = bif_type(Op, Src, Vst),
+ Type = propagate_fragility(Type0, Src, Vst),
set_type_reg(Type, Dst, Vst);
valfun_4(return, #vst{current=#st{numy=none}}=Vst) ->
assert_term({x,0}, Vst),
@@ -563,13 +567,20 @@ valfun_4({jump,{f,Lbl}}, Vst) ->
kill_state(branch_state(Lbl, Vst));
valfun_4({loop_rec,{f,Fail},Dst}, Vst0) ->
Vst = branch_state(Fail, Vst0),
- set_type_reg(term, Dst, Vst);
+ %% This term may not be part of the root set until
+ %% remove_message/0 is executed. If control transfers
+ %% to the loop_rec_end/1 instruction, no part of this
+ %% this term must be stored in a Y register.
+ set_type_reg({fragile,term}, Dst, Vst);
valfun_4({wait,_}, Vst) ->
+ verify_y_init(Vst),
kill_state(Vst);
valfun_4({wait_timeout,_,Src}, Vst) ->
assert_term(Src, Vst),
+ verify_y_init(Vst),
Vst;
valfun_4({loop_rec_end,_}, Vst) ->
+ verify_y_init(Vst),
kill_state(Vst);
valfun_4(timeout, #vst{current=St}=Vst) ->
Vst#vst{current=St#st{x=init_regs(0, term)}};
@@ -589,17 +600,17 @@ valfun_4({select_tuple_arity,Tuple,{f,Fail},{list,Choices}}, Vst) ->
kill_state(branch_arities(Choices, Tuple, branch_state(Fail, Vst)));
valfun_4({get_list,Src,D1,D2}, Vst0) ->
assert_type(cons, Src, Vst0),
- Vst = set_type_reg(term, D1, Vst0),
- set_type_reg(term, D2, Vst);
+ Vst = set_type_reg(term, Src, D1, Vst0),
+ set_type_reg(term, Src, D2, Vst);
valfun_4({get_hd,Src,Dst}, Vst) ->
assert_type(cons, Src, Vst),
- set_type_reg(term, Dst, Vst);
+ set_type_reg(term, Src, Dst, Vst);
valfun_4({get_tl,Src,Dst}, Vst) ->
assert_type(cons, Src, Vst),
- set_type_reg(term, Dst, Vst);
+ set_type_reg(term, Src, Dst, Vst);
valfun_4({get_tuple_element,Src,I,Dst}, Vst) ->
assert_type({tuple_element,I+1}, Src, Vst),
- set_type_reg(term, Dst, Vst);
+ set_type_reg(term, Src, Dst, Vst);
%% New bit syntax matching instructions.
valfun_4({test,bs_start_match2,{f,Fail},Live,[Ctx,NeedSlots],Ctx}, Vst0) ->
@@ -625,7 +636,7 @@ valfun_4({test,bs_start_match2,{f,Fail},Live,[Src,Slots],Dst}, Vst0) ->
verify_live(Live, Vst0),
Vst1 = prune_x_regs(Live, Vst0),
Vst = branch_state(Fail, Vst1),
- set_type_reg(bsm_match_state(Slots), Dst, Vst);
+ set_type_reg(bsm_match_state(Slots), Src, Dst, Vst);
valfun_4({test,bs_match_string,{f,Fail},[Ctx,_,_]}, Vst) ->
bsm_validate_context(Ctx, Vst),
branch_state(Fail, Vst);
@@ -650,7 +661,8 @@ valfun_4({test,bs_get_integer2,{f,Fail},Live,[Ctx,_,_,_],Dst}, Vst) ->
valfun_4({test,bs_get_float2,{f,Fail},Live,[Ctx,_,_,_],Dst}, Vst) ->
validate_bs_get(Fail, Ctx, Live, {float, []}, Dst, Vst);
valfun_4({test,bs_get_binary2,{f,Fail},Live,[Ctx,_,_,_],Dst}, Vst) ->
- validate_bs_get(Fail, Ctx, Live, term, Dst, Vst);
+ Type = propagate_fragility(term, [Ctx], Vst),
+ validate_bs_get(Fail, Ctx, Live, Type, Dst, Vst);
valfun_4({test,bs_get_utf8,{f,Fail},Live,[Ctx,_],Dst}, Vst) ->
validate_bs_get(Fail, Ctx, Live, {integer, []}, Dst, Vst);
valfun_4({test,bs_get_utf16,{f,Fail},Live,[Ctx,_],Dst}, Vst) ->
@@ -790,7 +802,7 @@ verify_get_map(Fail, Src, List, Vst0) ->
Vst2 = branch_state(Fail, Vst1),
Keys = extract_map_keys(List),
assert_unique_map_keys(Keys),
- verify_get_map_pair(List,Vst0,Vst2).
+ verify_get_map_pair(List, Src, Vst0, Vst2).
extract_map_vals([_Key,Val|T]) ->
[Val|extract_map_vals(T)];
@@ -800,10 +812,11 @@ extract_map_keys([Key,_Val|T]) ->
[Key|extract_map_keys(T)];
extract_map_keys([]) -> [].
-verify_get_map_pair([],_,Vst) -> Vst;
-verify_get_map_pair([Src,Dst|Vs],Vst0,Vsti) ->
+verify_get_map_pair([Src,Dst|Vs], Map, Vst0, Vsti0) ->
assert_term(Src, Vst0),
- verify_get_map_pair(Vs,Vst0,set_type_reg(term,Dst,Vsti)).
+ Vsti = set_type_reg(term, Map, Dst, Vsti0),
+ verify_get_map_pair(Vs, Map, Vst0, Vsti);
+verify_get_map_pair([], _Map, _Vst0, Vst) -> Vst.
verify_put_map(Fail, Src, Dst, Live, List, Vst0) ->
assert_type(map, Src, Vst0),
@@ -1093,10 +1106,11 @@ bsm_validate_context(Reg, Vst) ->
bsm_get_context({x,X}=Reg, #vst{current=#st{x=Xs}}=_Vst) when is_integer(X) ->
case gb_trees:lookup(X, Xs) of
{value,#ms{}=Ctx} -> Ctx;
+ {value,{fragile,#ms{}=Ctx}} -> Ctx;
_ -> error({no_bsm_context,Reg})
end;
bsm_get_context(Reg, _) -> error({bad_source,Reg}).
-
+
bsm_save(Reg, {atom,start}, Vst) ->
%% Save point refering to where the match started.
%% It is always valid. But don't forget to validate the context register.
@@ -1133,13 +1147,34 @@ set_type(Type, {x,_}=Reg, Vst) -> set_type_reg(Type, Reg, Vst);
set_type(Type, {y,_}=Reg, Vst) -> set_type_y(Type, Reg, Vst);
set_type(_, _, #vst{}=Vst) -> Vst.
-set_type_reg(Type, {x,X}=Reg, #vst{current=#st{x=Xs}=St}=Vst)
- when is_integer(X), 0 =< X ->
- check_limit(Reg),
- Vst#vst{current=St#st{x=gb_trees:enter(X, Type, Xs)}};
+set_type_reg(Type, Src, Dst, Vst) ->
+ case get_term_type_1(Src, Vst) of
+ {fragile,_} ->
+ set_type_reg(make_fragile(Type), Dst, Vst);
+ _ ->
+ set_type_reg(Type, Dst, Vst)
+ end.
+
+set_type_reg(Type, {x,_}=Reg, Vst) ->
+ set_type_x(Type, Reg, Vst);
set_type_reg(Type, Reg, Vst) ->
set_type_y(Type, Reg, Vst).
+set_type_x(Type, {x,X}=Reg, #vst{current=#st{x=Xs0}=St}=Vst)
+ when is_integer(X), 0 =< X ->
+ check_limit(Reg),
+ Xs = case gb_trees:lookup(X, Xs0) of
+ none ->
+ gb_trees:insert(X, Type, Xs0);
+ {value,{fragile,_}} ->
+ gb_trees:update(X, make_fragile(Type), Xs0);
+ {value,_} ->
+ gb_trees:update(X, Type, Xs0)
+ end,
+ Vst#vst{current=St#st{x=Xs}};
+set_type_x(Type, Reg, #vst{}) ->
+ error({invalid_store,Reg,Type}).
+
set_type_y(Type, {y,Y}=Reg, #vst{current=#st{y=Ys0}=St}=Vst)
when is_integer(Y), 0 =< Y ->
check_limit(Reg),
@@ -1157,6 +1192,9 @@ set_type_y(Type, {y,Y}=Reg, #vst{current=#st{y=Ys0}=St}=Vst)
Vst#vst{current=St#st{y=Ys}};
set_type_y(Type, Reg, #vst{}) -> error({invalid_store,Reg,Type}).
+make_fragile({fragile,_}=Type) -> Type;
+make_fragile(Type) -> {fragile,Type}.
+
set_catch_end({y,Y}, #vst{current=#st{y=Ys0}=St}=Vst) ->
Ys = gb_trees:update(Y, initialized, Ys0),
Vst#vst{current=St#st{y=Ys}}.
@@ -1257,9 +1295,26 @@ assert_term(Src, Vst) ->
%%
%% map Map.
%%
+%%
+%%
+%% FRAGILITY
+%% ---------
+%%
+%% The loop_rec/2 instruction may return a reference to a term that is
+%% not part of the root set. That term or any part of it must not be
+%% included in a garbage collection. Therefore, the term (or any part
+%% of it) must not be stored in an Y register.
+%%
+%% Such terms are wrapped in a {fragile,Type} tuple, where Type is one
+%% of the types described above.
assert_type(WantedType, Term, Vst) ->
- assert_type(WantedType, get_term_type(Term, Vst)).
+ case get_term_type(Term, Vst) of
+ {fragile,Type} ->
+ assert_type(WantedType, Type);
+ Type ->
+ assert_type(WantedType, Type)
+ end.
assert_type(Correct, Correct) -> ok;
assert_type(float, {float,_}) -> ok;
@@ -1285,14 +1340,19 @@ assert_type(Needed, Actual) ->
%% is inconsistent, and we know that some instructions will never
%% be executed at run-time.
-upgrade_tuple_type({tuple,[Sz]}, {tuple,[OldSz]}=T) when Sz < OldSz ->
+upgrade_tuple_type(NewType, {fragile,OldType}) ->
+ make_fragile(upgrade_tuple_type_1(NewType, OldType));
+upgrade_tuple_type(NewType, OldType) ->
+ upgrade_tuple_type_1(NewType, OldType).
+
+upgrade_tuple_type_1({tuple,[Sz]}, {tuple,[OldSz]}=T) when Sz < OldSz ->
%% The old type has a higher value for the least tuple size.
T;
-upgrade_tuple_type({tuple,[Sz]}, {tuple,OldSz}=T)
+upgrade_tuple_type_1({tuple,[Sz]}, {tuple,OldSz}=T)
when is_integer(Sz), is_integer(OldSz), Sz =< OldSz ->
%% The old size is exact, and the new size is smaller than the old size.
T;
-upgrade_tuple_type({tuple,_}=T, _) ->
+upgrade_tuple_type_1({tuple,_}=T, _) ->
%% The new type information is exact or has a higher value for
%% the least tuple size.
%% Note that inconsistencies are also handled in this
@@ -1459,6 +1519,14 @@ merge_y_regs_1(_, _, Regs) -> Regs.
%% merge_types(Type1, Type2) -> Type
%% Return the most specific type possible.
%% Note: Type1 must NOT be the same as Type2.
+merge_types({fragile,Same}=Type, Same) ->
+ Type;
+merge_types({fragile,T1}, T2) ->
+ make_fragile(merge_types(T1, T2));
+merge_types(Same, {fragile,Same}=Type) ->
+ Type;
+merge_types(T1, {fragile,T2}) ->
+ make_fragile(merge_types(T1, T2));
merge_types(uninitialized=I, _) -> I;
merge_types(_, uninitialized=I) -> I;
merge_types(initialized=I, _) -> I;
@@ -1509,6 +1577,10 @@ verify_y_init(#vst{current=#st{y=Ys}}) ->
verify_y_init_1([]) -> ok;
verify_y_init_1([{Y,uninitialized}|_]) ->
error({uninitialized_reg,{y,Y}});
+verify_y_init_1([{Y,{fragile,_}}|_]) ->
+ %% Unsafe. This term may be outside any heap belonging
+ %% to the process and would be corrupted by a GC.
+ error({fragile_message_reference,{y,Y}});
verify_y_init_1([{_,_}|Ys]) ->
verify_y_init_1(Ys).
@@ -1554,6 +1626,27 @@ eat_heap_float(#vst{current=#st{hf=HeapFloats0}=St}=Vst) ->
Vst#vst{current=St#st{hf=HeapFloats}}
end.
+remove_fragility(#vst{current=#st{x=Xs0,y=Ys0}=St0}=Vst) ->
+ F = fun(_, {fragile,Type}) -> Type;
+ (_, Type) -> Type
+ end,
+ Xs = gb_trees:map(F, Xs0),
+ Ys = gb_trees:map(F, Ys0),
+ St = St0#st{x=Xs,y=Ys},
+ Vst#vst{current=St}.
+
+propagate_fragility(Type, Ss, Vst) ->
+ F = fun(S) ->
+ case get_term_type_1(S, Vst) of
+ {fragile,_} -> true;
+ _ -> false
+ end
+ end,
+ case any(F, Ss) of
+ true -> make_fragile(Type);
+ false -> Type
+ end.
+
bif_type('-', Src, Vst) ->
arith_type(Src, Vst);
bif_type('+', Src, Vst) ->
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-05 18:24:13 +0000