From ba7e4db73922f45fc9c36bc0820e49264972ccf3 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?John=20H=C3=B6gberg?= Date: Wed, 20 Feb 2019 15:11:06 +0100 Subject: beam_validator: Refactor liveness/stack initialization checks --- lib/compiler/src/beam_validator.erl | 125 +++++++++++++++++------------ lib/compiler/test/beam_validator_SUITE.erl | 24 +++--- 2 files changed, 86 insertions(+), 63 deletions(-) (limited to 'lib/compiler') diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl index 163956f255..f4203baf44 100644 --- a/lib/compiler/src/beam_validator.erl +++ b/lib/compiler/src/beam_validator.erl @@ -1651,26 +1651,15 @@ check_try_catch_tags(Type, {y,N}=Reg, Vst) -> %% scanned when an exception occurs, the innermost try/catch tag is found %% first. case is_try_catch_tag(Type) of - true -> check_try_catch_tags_1(N - 1, Reg, Vst, []); - false -> ok + true -> + case collect_try_catch_tags(N - 1, Vst, []) of + [_|_]=Bad -> error({bad_try_catch_nesting, Reg, Bad}); + [] -> ok + end; + false -> + ok end. -check_try_catch_tags_1(N, _Reg, _Vst, []) when N < 0 -> - ok; -check_try_catch_tags_1(N, Reg, _Vst, Bad) when N < 0 -> - error({bad_try_catch_nesting, Reg, Bad}); -check_try_catch_tags_1(N, Reg, Vst, Acc0) -> - Tag = get_raw_type({y, N}, Vst), - Acc = case is_try_catch_tag(Tag) of - true -> [{{y, N}, Tag} | Acc0]; - false -> Acc0 - end, - check_try_catch_tags_1(N - 1, Reg, Vst, Acc). - -is_try_catch_tag({catchtag,_}) -> true; -is_try_catch_tag({trytag,_}) -> true; -is_try_catch_tag(_) -> false. - is_reg_defined({x,_}=Reg, Vst) -> is_type_defined_x(Reg, Vst); is_reg_defined({y,_}=Reg, Vst) -> is_type_defined_y(Reg, Vst); is_reg_defined(V, #vst{}) -> error({not_a_register, V}). @@ -1977,7 +1966,7 @@ get_raw_type({y,Y}, #vst{current=#st{y=Ys}}) when is_integer(Y) -> {value,Type} -> Type; none -> uninitialized end; -get_raw_type(Src, _) -> +get_raw_type(Src, #vst{}) -> get_literal_type(Src). get_def(Src, #vst{current=#st{defs=Defs}}) -> @@ -2212,44 +2201,78 @@ merge_aliases(Al0, Al1) when map_size(Al0) =< map_size(Al1) -> merge_aliases(Al0, Al1) -> merge_aliases(Al1, Al0). -verify_y_init(#vst{current=#st{y=Ys}}) -> - verify_y_init_1(gb_trees:to_list(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). - -verify_live(0, #vst{}) -> ok; -verify_live(N, #vst{current=#st{x=Xs}}) -> - verify_live_1(N, Xs). - -verify_live_1(0, _) -> ok; -verify_live_1(N, Xs) when is_integer(N) -> - X = N-1, - case gb_trees:is_defined(X, Xs) of - false -> error({{x,X},not_live}); - true -> verify_live_1(X, Xs) +verify_y_init(#vst{current=#st{numy=NumY,y=Ys}}=Vst) + when is_integer(NumY), NumY > 0 -> + {HighestY, _} = gb_trees:largest(Ys), + true = NumY > HighestY, %Assertion. + verify_y_init_1(NumY - 1, Vst), + ok; +verify_y_init(#vst{current=#st{numy=undecided,y=Ys}}=Vst) -> + case gb_trees:is_empty(Ys) of + true -> + ok; + false -> + {HighestY, _} = gb_trees:largest(Ys), + verify_y_init_1(HighestY, Vst) end; -verify_live_1(N, _) -> error({bad_number_of_live_regs,N}). +verify_y_init(#vst{}) -> + ok. -verify_no_ct(#vst{current=#st{numy=none}}) -> ok; +verify_y_init_1(-1, _Vst) -> + ok; +verify_y_init_1(Y, Vst) -> + Reg = {y, Y}, + case get_raw_type(Reg, Vst) of + uninitialized -> + error({uninitialized_reg,Reg}); + {fragile, _} -> + %% Unsafe. This term may be outside any heap belonging to the + %% process and would be corrupted by a GC. + error({fragile_message_reference,Reg}); + _ -> + verify_y_init_1(Y - 1, Vst) + end. + +verify_live(0, _Vst) -> + ok; +verify_live(Live, Vst) when is_integer(Live), 0 < Live, Live =< 1023 -> + verify_live_1(Live - 1, Vst); +verify_live(Live, _Vst) -> + error({bad_number_of_live_regs,Live}). + +verify_live_1(-1, _) -> + ok; +verify_live_1(X, Vst) when is_integer(X) -> + Reg = {x, X}, + case get_raw_type(Reg, Vst) of + uninitialized -> error({Reg, not_live}); + _ -> verify_live_1(X - 1, Vst) + end. + +verify_no_ct(#vst{current=#st{numy=none}}) -> + ok; verify_no_ct(#vst{current=#st{numy=undecided}}) -> error(unknown_size_of_stackframe); -verify_no_ct(#vst{current=#st{y=Ys}}) -> - case [Y || Y <- gb_trees:to_list(Ys), verify_no_ct_1(Y)] of - [] -> ok; - CT -> error({unfinished_catch_try,CT}) +verify_no_ct(#vst{current=St}=Vst) -> + case collect_try_catch_tags(St#st.numy - 1, Vst, []) of + [_|_]=Bad -> error({unfinished_catch_try,Bad}); + [] -> ok end. -verify_no_ct_1({_, {catchtag, _}}) -> true; -verify_no_ct_1({_, {trytag, _}}) -> true; -verify_no_ct_1({_, _}) -> false. +%% Collects all try/catch tags, walking down from the Nth stack position. +collect_try_catch_tags(-1, _Vst, Acc) -> + Acc; +collect_try_catch_tags(Y, Vst, Acc0) -> + Tag = get_raw_type({y, Y}, Vst), + Acc = case is_try_catch_tag(Tag) of + true -> [{{y, Y}, Tag} | Acc0]; + false -> Acc0 + end, + collect_try_catch_tags(Y - 1, Vst, Acc). + +is_try_catch_tag({catchtag,_}) -> true; +is_try_catch_tag({trytag,_}) -> true; +is_try_catch_tag(_) -> false. eat_heap(N, #vst{current=#st{h=Heap0}=St}=Vst) -> case Heap0-N of diff --git a/lib/compiler/test/beam_validator_SUITE.erl b/lib/compiler/test/beam_validator_SUITE.erl index cdf420aee5..2660bf222c 100644 --- a/lib/compiler/test/beam_validator_SUITE.erl +++ b/lib/compiler/test/beam_validator_SUITE.erl @@ -159,7 +159,7 @@ merge_undefined(Config) when is_list(Config) -> [{{t,handle_call,2}, {{call_ext,1,{extfunc,erlang,exit,1}}, 10, - {uninitialized_reg,{y,0}}}}] = Errors, + {uninitialized_reg,{y,_}}}}] = Errors, ok. uninit(Config) when is_list(Config) -> @@ -539,37 +539,37 @@ receive_stacked(Config) -> [{{receive_stacked,f1,0}, {{loop_rec_end,{f,3}}, 17, - {fragile_message_reference,{y,0}}}}, + {fragile_message_reference,{y,_}}}}, {{receive_stacked,f2,0}, - {{test_heap,3,0},10,{fragile_message_reference,{y,1}}}}, + {{test_heap,3,0},10,{fragile_message_reference,{y,_}}}}, {{receive_stacked,f3,0}, - {{test_heap,3,0},10,{fragile_message_reference,{y,1}}}}, + {{test_heap,3,0},10,{fragile_message_reference,{y,_}}}}, {{receive_stacked,f4,0}, - {{test_heap,3,0},10,{fragile_message_reference,{y,1}}}}, + {{test_heap,3,0},10,{fragile_message_reference,{y,_}}}}, {{receive_stacked,f5,0}, {{loop_rec_end,{f,23}}, 23, - {fragile_message_reference,{y,1}}}}, + {fragile_message_reference,{y,_}}}}, {{receive_stacked,f6,0}, - {{gc_bif,byte_size,{f,29},0,[{y,0}],{x,0}}, + {{gc_bif,byte_size,{f,29},0,[{y,_}],{x,0}}, 12, - {fragile_message_reference,{y,0}}}}, + {fragile_message_reference,{y,_}}}}, {{receive_stacked,f7,0}, {{loop_rec_end,{f,33}}, 20, - {fragile_message_reference,{y,0}}}}, + {fragile_message_reference,{y,_}}}}, {{receive_stacked,f8,0}, {{loop_rec_end,{f,38}}, 20, - {fragile_message_reference,{y,0}}}}, + {fragile_message_reference,{y,_}}}}, {{receive_stacked,m1,0}, {{loop_rec_end,{f,43}}, 19, - {fragile_message_reference,{y,0}}}}, + {fragile_message_reference,{y,_}}}}, {{receive_stacked,m2,0}, {{loop_rec_end,{f,48}}, 33, - {fragile_message_reference,{y,0}}}}] = Errors, + {fragile_message_reference,{y,_}}}}] = Errors, %% Compile the original source code as a smoke test. Data = proplists:get_value(data_dir, Config), -- cgit v1.2.3