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authorBjörn Gustavsson <[email protected]>2018-02-27 08:39:28 +0100
committerBjörn Gustavsson <[email protected]>2018-03-01 11:30:41 +0100
commite07318afab8a4e2040c3d0321afcfc9fc978db5e (patch)
tree95f553773481a07bdc21f035fd45813c4aad034b
parent478b43211bbe96018b63cbf6c6d567550a6e8a2c (diff)
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Enhance beam_validator to check proper nesting of try/catch and catch
Every catch or try/catch must use a lower Y register number than any enclosing catch or try/catch. That will ensure that when the stack is scanned when an exception occurs, the innermost try/catch tag is found first.
-rw-r--r--lib/compiler/src/beam_validator.erl24
-rw-r--r--lib/compiler/test/beam_validator_SUITE.erl12
-rw-r--r--lib/compiler/test/beam_validator_SUITE_data/bad_try_catch_nesting.S64
3 files changed, 98 insertions, 2 deletions
diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl
index 9de773542e..c30ab34ac7 100644
--- a/lib/compiler/src/beam_validator.erl
+++ b/lib/compiler/src/beam_validator.erl
@@ -1153,6 +1153,7 @@ set_type_y(Type, {y,Y}=Reg, #vst{current=#st{y=Ys0}=St}=Vst)
{value,_} ->
gb_trees:update(Y, Type, Ys0)
end,
+ check_try_catch_tags(Type, Y, Ys0),
Vst#vst{current=St#st{y=Ys}};
set_type_y(Type, Reg, #vst{}) -> error({invalid_store,Reg,Type}).
@@ -1160,6 +1161,29 @@ 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}}.
+check_try_catch_tags(Type, LastY, Ys) ->
+ case is_try_catch_tag(Type) of
+ false ->
+ ok;
+ true ->
+ %% Every catch or try/catch must use a lower Y register
+ %% number than any enclosing catch or try/catch. That will
+ %% ensure that when the stack is scanned when an
+ %% exception occurs, the innermost try/catch tag is found
+ %% first.
+ Bad = [{{y,Y},Tag} || {Y,Tag} <- gb_trees:to_list(Ys),
+ Y < LastY, is_try_catch_tag(Tag)],
+ case Bad of
+ [] ->
+ ok;
+ [_|_] ->
+ error({bad_try_catch_nesting,{y,LastY},Bad})
+ end
+ end.
+
+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);
diff --git a/lib/compiler/test/beam_validator_SUITE.erl b/lib/compiler/test/beam_validator_SUITE.erl
index 63a13281a8..b8fff7b100 100644
--- a/lib/compiler/test/beam_validator_SUITE.erl
+++ b/lib/compiler/test/beam_validator_SUITE.erl
@@ -33,7 +33,7 @@
state_after_fault_in_catch/1,no_exception_in_catch/1,
undef_label/1,illegal_instruction/1,failing_gc_guard_bif/1,
map_field_lists/1,cover_bin_opt/1,
- val_dsetel/1,bad_tuples/1]).
+ val_dsetel/1,bad_tuples/1,bad_try_catch_nesting/1]).
-include_lib("common_test/include/ct.hrl").
@@ -62,7 +62,7 @@ groups() ->
state_after_fault_in_catch,no_exception_in_catch,
undef_label,illegal_instruction,failing_gc_guard_bif,
map_field_lists,cover_bin_opt,val_dsetel,
- bad_tuples]}].
+ bad_tuples,bad_try_catch_nesting]}].
init_per_suite(Config) ->
Config.
@@ -523,6 +523,14 @@ bad_tuples(Config) ->
ok.
+bad_try_catch_nesting(Config) ->
+ Errors = do_val(bad_try_catch_nesting, Config),
+ [{{bad_try_catch_nesting,main,2},
+ {{'try',{y,2},{f,3}},
+ 7,
+ {bad_try_catch_nesting,{y,2},[{{y,1},{trytag,[5]}}]}}}] = Errors,
+ ok.
+
%%%-------------------------------------------------------------------------
transform_remove(Remove, Module) ->
diff --git a/lib/compiler/test/beam_validator_SUITE_data/bad_try_catch_nesting.S b/lib/compiler/test/beam_validator_SUITE_data/bad_try_catch_nesting.S
new file mode 100644
index 0000000000..9f1b21a17b
--- /dev/null
+++ b/lib/compiler/test/beam_validator_SUITE_data/bad_try_catch_nesting.S
@@ -0,0 +1,64 @@
+{module, bad_try_catch_nesting}. %% version = 0
+
+{exports, [{main,2},{module_info,0},{module_info,1}]}.
+
+{attributes, []}.
+
+{labels, 11}.
+
+
+{function, main, 2, 2}.
+ {label,1}.
+ {line,[{location,"bad_try_catch_nesting.erl",4}]}.
+ {func_info,{atom,bad_try_catch_nesting},{atom,main},2}.
+ {label,2}.
+ {allocate_zero,3,2}.
+ {'try',{y,1},{f,5}}.
+ {move,{x,1},{y,0}}.
+ {'try',{y,2},{f,3}}.
+ {line,[{location,"bad_try_catch_nesting.erl",7}]}.
+ {call_fun,0}.
+ {try_end,{y,2}}.
+ {jump,{f,4}}.
+ {label,3}.
+ {try_case,{y,2}}.
+ {test,is_ne_exact,{f,4},[{x,0},{atom,error}]}.
+ {line,[]}.
+ {bif,raise,{f,0},[{x,2},{x,1}],{x,0}}.
+ {label,4}.
+ {move,{y,0},{x,0}}.
+ {kill,{y,0}}.
+ {line,[{location,"bad_try_catch_nesting.erl",12}]}.
+ {call_fun,0}.
+ {try_end,{y,1}}.
+ {deallocate,3}.
+ return.
+ {label,5}.
+ {try_case,{y,1}}.
+ {test,is_eq_exact,{f,6},[{x,0},{atom,throw}]}.
+ {deallocate,3}.
+ return.
+ {label,6}.
+ {line,[]}.
+ {bif,raise,{f,0},[{x,2},{x,1}],{x,0}}.
+
+
+{function, module_info, 0, 8}.
+ {label,7}.
+ {line,[]}.
+ {func_info,{atom,bad_try_catch_nesting},{atom,module_info},0}.
+ {label,8}.
+ {move,{atom,bad_try_catch_nesting},{x,0}}.
+ {line,[]}.
+ {call_ext_only,1,{extfunc,erlang,get_module_info,1}}.
+
+
+{function, module_info, 1, 10}.
+ {label,9}.
+ {line,[]}.
+ {func_info,{atom,bad_try_catch_nesting},{atom,module_info},1}.
+ {label,10}.
+ {move,{x,0},{x,1}}.
+ {move,{atom,bad_try_catch_nesting},{x,0}}.
+ {line,[]}.
+ {call_ext_only,2,{extfunc,erlang,get_module_info,2}}.