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author | John Högberg <[email protected]> | 2019-07-11 09:53:41 +0200 |
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committer | John Högberg <[email protected]> | 2019-07-11 11:04:08 +0200 |
commit | 315b13cfc8a9efea6a616cbecfe5171da0db63bb (patch) | |
tree | 76a29333680b040bdb6b8db9575de3b98db2d246 /lib/compiler | |
parent | 5c116e4fbf19632c195b8b5cb32d248c8744eff1 (diff) | |
download | otp-315b13cfc8a9efea6a616cbecfe5171da0db63bb.tar.gz otp-315b13cfc8a9efea6a616cbecfe5171da0db63bb.tar.bz2 otp-315b13cfc8a9efea6a616cbecfe5171da0db63bb.zip |
beam_validator: Improve type inference on inequality
Both sides need to be inferred, and we should infer as if we've
made an exact match when we know that LHS is single-valued. This
was done for select_val, but we failed to do so for is_ne_exact
et al.
Diffstat (limited to 'lib/compiler')
-rw-r--r-- | lib/compiler/src/beam_validator.erl | 50 | ||||
-rw-r--r-- | lib/compiler/test/beam_validator_SUITE.erl | 23 |
2 files changed, 48 insertions, 25 deletions
diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl index a2e4707758..abc3aa3875 100644 --- a/lib/compiler/src/beam_validator.erl +++ b/lib/compiler/src/beam_validator.erl @@ -1531,21 +1531,8 @@ validate_select_val(Fail, [Val,{f,L}|T], Src, Vst0) -> update_ne_types(Src, Val, FailVst) end), validate_select_val(Fail, T, Src, Vst); -validate_select_val(Fail, [], Src, Vst) -> +validate_select_val(Fail, [], _Src, Vst) -> branch(Fail, Vst, - fun(FailVst) -> - FailType = get_term_type(Src, FailVst), - case beam_types:get_singleton_value(FailType) of - {ok, Value} -> - %% This is the only possible value at the fail - %% label, so we can infer types as if we matched it - %% directly. - Lit = value_to_literal(Value), - update_eq_types(Src, Lit, FailVst); - error -> - FailVst - end - end, fun(SuccVst) -> %% The next instruction is never executed. kill_state(SuccVst) @@ -1793,17 +1780,21 @@ update_type(Merge, With, Literal, Vst) -> end. update_eq_types(LHS, RHS, Vst0) -> - Vst1 = infer_types(eq_exact, LHS, RHS, Vst0), + LType = get_term_type(LHS, Vst0), + RType = get_term_type(RHS, Vst0), - T1 = get_term_type(LHS, Vst1), - T2 = get_term_type(RHS, Vst1), + Vst1 = update_type(fun meet/2, RType, LHS, Vst0), + Vst = update_type(fun meet/2, LType, RHS, Vst1), - Vst = update_type(fun meet/2, T2, LHS, Vst1), - update_type(fun meet/2, T1, RHS, Vst). + infer_types(eq_exact, LHS, RHS, Vst). update_ne_types(LHS, RHS, Vst0) -> - Vst = infer_types(ne_exact, LHS, RHS, Vst0), + Vst1 = update_ne_types_1(LHS, RHS, Vst0), + Vst = update_ne_types_1(RHS, LHS, Vst1), + + infer_types(ne_exact, LHS, RHS, Vst). +update_ne_types_1(LHS, RHS, Vst0) -> %% While updating types on equality is fairly straightforward, inequality %% is a bit trickier since all we know is that the *value* of LHS differs %% from RHS, so we can't blindly subtract their types. @@ -1813,10 +1804,23 @@ update_ne_types(LHS, RHS, Vst0) -> %% #t_integer{} we would erroneously infer that the new type is float. %% %% Therefore, we only subtract when we know that RHS has a specific value. - RType = get_term_type(RHS, Vst), + RType = get_term_type(RHS, Vst0), case beam_types:is_singleton_type(RType) of - true -> update_type(fun subtract/2, RType, LHS, Vst); - false -> Vst + true -> + Vst = update_type(fun subtract/2, RType, LHS, Vst0), + + %% If LHS has a specific value after subtraction we can infer types + %% as if we've made an exact match, which is much stronger than + %% ne_exact. + LType = get_term_type(LHS, Vst), + case beam_types:get_singleton_value(LType) of + {ok, Value} -> + infer_types(eq_exact, LHS, value_to_literal(Value), Vst); + error -> + Vst + end; + false -> + Vst0 end. %% Helper functions for the above. diff --git a/lib/compiler/test/beam_validator_SUITE.erl b/lib/compiler/test/beam_validator_SUITE.erl index d49d5af9c3..326ad9042f 100644 --- a/lib/compiler/test/beam_validator_SUITE.erl +++ b/lib/compiler/test/beam_validator_SUITE.erl @@ -35,7 +35,7 @@ map_field_lists/1,cover_bin_opt/1, val_dsetel/1,bad_tuples/1,bad_try_catch_nesting/1, receive_stacked/1,aliased_types/1,type_conflict/1, - infer_on_eq/1,infer_dead_value/1]). + infer_on_eq/1,infer_dead_value/1,infer_on_ne/1]). -include_lib("common_test/include/ct.hrl"). @@ -65,7 +65,7 @@ groups() -> map_field_lists,cover_bin_opt,val_dsetel, bad_tuples,bad_try_catch_nesting, receive_stacked,aliased_types,type_conflict, - infer_on_eq,infer_dead_value]}]. + infer_on_eq,infer_dead_value,infer_on_ne]}]. init_per_suite(Config) -> test_lib:recompile(?MODULE), @@ -700,6 +700,25 @@ idv_1({_A, _B, _C, _D, _E, F, G}, idv_1(_A, _B) -> error. +%% ERL-998; type inference for select_val (#b_switch{}) was more clever than +%% that for is_ne_exact (#b_br{}), sometimes failing validation when the type +%% optimization pass acted on the former and the validator got the latter. + +-record(ion, {state}). + +infer_on_ne(Config) when is_list(Config) -> + #ion{state = closing} = ion_1(#ion{ state = id(open) }), + #ion{state = closing} = ion_close(#ion{ state = open }), + ok. + +ion_1(State = #ion{state = open}) -> ion_2(State); +ion_1(State = #ion{state = closing}) -> ion_2(State). + +ion_2(State = #ion{state = open}) -> ion_close(State); +ion_2(#ion{state = closing}) -> ok. + +ion_close(State = #ion{}) -> State#ion{state = closing}. + %%%------------------------------------------------------------------------- transform_remove(Remove, Module) -> |