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authorJohn Högberg <[email protected]>2019-02-26 09:14:36 +0100
committerJohn Högberg <[email protected]>2019-02-27 14:59:41 +0100
commit1d78eea0306f560f6219fa34e0f5f9689f9e613c (patch)
treef7af6f816cc96c39260683551f4692ccc6795fe6
parent36b7654dc152f6b3343afb664a7b260dcc06c799 (diff)
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beam_validator: Make call argument validation stricter
We used to cheat by checking if it were possible to meet the Given and Required types, which caught the most common problems but potentially let tuple element conflicts pass through. This was a compromise to let the thing "work" while we were refactoring the validator, but we can be a lot stricter now that its type tracking capabilities approach those of the type optimization pass.
-rw-r--r--lib/compiler/src/beam_validator.erl59
1 files changed, 47 insertions, 12 deletions
diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl
index fa31a47128..af0aded85c 100644
--- a/lib/compiler/src/beam_validator.erl
+++ b/lib/compiler/src/beam_validator.erl
@@ -61,9 +61,9 @@ type_anno(number) -> number;
type_anno(nil) -> nil.
-spec type_anno(term(), term()) -> term().
-type_anno(atom, Value) -> {atom, Value};
-type_anno(float, Value) -> {float, Value};
-type_anno(integer, Value) -> {integer, Value}.
+type_anno(atom, Value) when is_atom(Value) -> {atom, Value};
+type_anno(float, Value) when is_float(Value) -> {float, Value};
+type_anno(integer, Value) when is_integer(Value) -> {integer, Value}.
-spec type_anno(term(), term(), term(), term()) -> term().
type_anno(tuple, Size, Exact, Elements) when is_integer(Size), Size >= 0,
@@ -1182,25 +1182,58 @@ verify_arg_type(Lbl, Reg, #ms{}, #vst{ft=Ft}) ->
end;
verify_arg_type(Lbl, Reg, GivenType, #vst{ft=Ft}) ->
case gb_trees:lookup({Lbl, Reg}, Ft) of
- {value, bool} when GivenType =:= {atom, true};
- GivenType =:= {atom, false};
- GivenType =:= {atom, []} ->
- %% We don't yet support upgrading true/false to bool, so we
- %% assume unknown atoms can be bools when validating calls.
- ok;
{value, #ms{}} ->
%% Functions that accept match contexts also accept all other
%% terms. This will change once we support union types.
ok;
{value, RequiredType} ->
- case meet(GivenType, RequiredType) of
- none -> error({bad_arg_type, Reg, GivenType, RequiredType});
- _ -> ok
+ case vat_1(GivenType, RequiredType) of
+ true -> ok;
+ false -> error({bad_arg_type, Reg, GivenType, RequiredType})
end;
none ->
ok
end.
+%% Checks whether the Given argument is compatible with the Required one. This
+%% is essentially a relaxed version of 'meet(Given, Req) =:= Given', where we
+%% accept that the Given value has the right type but not necessarily the exact
+%% same value; if {atom,gurka} is required, we'll consider {atom,[]} valid.
+%%
+%% This will catch all problems that could crash the emulator, like passing a
+%% 1-tuple when the callee expects a 3-tuple, but some value errors might slip
+%% through.
+vat_1(Same, Same) -> true;
+vat_1({atom,A}, {atom,B}) -> A =:= B orelse is_list(A) orelse is_list(B);
+vat_1({atom,A}, bool) -> is_boolean(A) orelse is_list(A);
+vat_1(bool, {atom,B}) -> is_boolean(B) orelse is_list(B);
+vat_1(cons, list) -> true;
+vat_1({float,A}, {float,B}) -> A =:= B orelse is_list(A) orelse is_list(B);
+vat_1({float,_}, number) -> true;
+vat_1({integer,A}, {integer,B}) -> A =:= B orelse is_list(A) orelse is_list(B);
+vat_1({integer,_}, number) -> true;
+vat_1(_, {literal,_}) -> false;
+vat_1({literal,_}=Lit, Required) -> vat_1(get_literal_type(Lit), Required);
+vat_1(nil, list) -> true;
+vat_1({tuple,SzA,EsA}, {tuple,SzB,EsB}) ->
+ if
+ is_list(SzB) ->
+ tuple_sz(SzA) >= tuple_sz(SzB) andalso vat_elements(EsA, EsB);
+ SzA =:= SzB ->
+ vat_elements(EsA, EsB);
+ SzA =/= SzB ->
+ false
+ end;
+vat_1(_, _) -> false.
+
+vat_elements(EsA, EsB) ->
+ maps:fold(fun(Key, Req, Acc) ->
+ case EsA of
+ #{ Key := Given } -> Acc andalso vat_1(Given, Req);
+ #{} -> false
+ end
+ end, true, EsB).
+
allocate(Tag, Stk, Heap, Live, #vst{current=#st{numy=none}=St}=Vst0) ->
verify_live(Live, Vst0),
Vst1 = Vst0#vst{current=St#st{numy=Stk}},
@@ -1871,6 +1904,8 @@ join(bool, {atom,A}) ->
join_bool(A);
join({atom,A}, bool) ->
join_bool(A);
+join({atom,A}, {atom,B}) when is_boolean(A), is_boolean(B) ->
+ bool;
join({atom,_}, {atom,_}) ->
{atom,[]};
join(#ms{id=Id1,valid=B1,slots=Slots1},