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authorJohn Högberg <[email protected]>2019-02-20 15:11:06 +0100
committerJohn Högberg <[email protected]>2019-02-21 12:25:15 +0100
commitba7e4db73922f45fc9c36bc0820e49264972ccf3 (patch)
treeed195b457e2e3fc541541d0f0e947cb545779482
parentfb52e4790257f5f8f3cc2d214b5f633e613ed932 (diff)
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beam_validator: Refactor liveness/stack initialization checks
-rw-r--r--lib/compiler/src/beam_validator.erl125
-rw-r--r--lib/compiler/test/beam_validator_SUITE.erl24
2 files changed, 86 insertions, 63 deletions
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),