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authorBjörn Gustavsson <[email protected]>2015-02-17 11:16:44 +0100
committerBjörn Gustavsson <[email protected]>2015-02-18 13:04:21 +0100
commitd52142f95858fc2ea461e9b2b52c5835e39886d8 (patch)
tree34ca31d35e67f406819f541a21fce73ef16b040a /lib/compiler/src
parentb2eec25db0bca618853b163ea34c4f9f4ef7f3f1 (diff)
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beam_validator: Tighten and simplify map validation code
The assert_strict_literal_termorder/1 function is used to validate the get_map_elements and has_map_fields instructions. In neither case is it useful to allow an empty lists of fields, so we should no longer allow an empty list. The mmap/2 function is cute, but it is used in only one place, so it is much simpler to write a special-purpose function to extract the keys from the list of map pairs.
Diffstat (limited to 'lib/compiler/src')
-rw-r--r--lib/compiler/src/beam_validator.erl56
1 files changed, 26 insertions, 30 deletions
diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl
index c156cf79fe..1f2448d433 100644
--- a/lib/compiler/src/beam_validator.erl
+++ b/lib/compiler/src/beam_validator.erl
@@ -891,10 +891,14 @@ valfun_4(_, _) ->
verify_get_map(Fail, Src, List, Vst0) ->
assert_term(Src, Vst0),
Vst1 = branch_state(Fail, Vst0),
- Lits = mmap(fun(L,_R) -> [L] end, List),
- assert_strict_literal_termorder(Lits),
+ Keys = extract_map_keys(List),
+ assert_strict_literal_termorder(Keys),
verify_get_map_pair(List,Vst0,Vst1).
+extract_map_keys([Key,_Val|T]) ->
+ [Key|extract_map_keys(T)];
+extract_map_keys([]) -> [].
+
verify_get_map_pair([],_,Vst) -> Vst;
verify_get_map_pair([Src,Dst|Vs],Vst0,Vsti) ->
assert_term(Src, Vst0),
@@ -1122,38 +1126,30 @@ assert_freg_set(Fr, _) -> error({bad_source,Fr}).
%%% Maps
-%% ensure that a list of literals has a strict
-%% ascending term order (also meaning unique literals).
-%% Single item lists may have registers.
-assert_strict_literal_termorder([_]) -> ok;
-assert_strict_literal_termorder(Ls) ->
- Vs = lists:map(fun (L) -> get_literal(L) end, Ls),
+%% A single item list may be either a list or a register.
+%%
+%% A list with more than item must contain literals in
+%% ascending term order.
+%%
+%% An empty list is not allowed.
+
+assert_strict_literal_termorder([]) ->
+ %% There is no reason to use the get_map_elements and
+ %% has_map_fields instructions with empty lists.
+ error(empty_field_list);
+assert_strict_literal_termorder([_]) ->
+ ok;
+assert_strict_literal_termorder([_,_|_]=Ls) ->
+ Vs = [get_literal(L) || L <- Ls],
case check_strict_value_termorder(Vs) of
true -> ok;
- false -> error({not_strict_order, Ls})
+ false -> error(not_strict_order)
end.
-%% usage:
-%% mmap(fun(A,B) -> [{A,B}] end, [1,2,3,4]),
-%% [{1,2},{3,4}]
-
-mmap(F,List) ->
- {arity,Ar} = erlang:fun_info(F,arity),
- mmap(F,Ar,List).
-mmap(_F,_,[]) -> [];
-mmap(F,Ar,List) ->
- {Hd,Tl} = lists:split(Ar,List),
- apply(F,Hd) ++ mmap(F,Ar,Tl).
-
-check_strict_value_termorder([]) -> true;
-check_strict_value_termorder([_]) -> true;
-check_strict_value_termorder([V1,V2]) ->
- erts_internal:cmp_term(V1,V2) < 0;
-check_strict_value_termorder([V1,V2|Vs]) ->
- case erts_internal:cmp_term(V1,V2) < 0 of
- true -> check_strict_value_termorder([V2|Vs]);
- false -> false
- end.
+check_strict_value_termorder([V1|[V2|_]=Vs]) ->
+ erts_internal:cmp_term(V1, V2) < 0 andalso
+ check_strict_value_termorder(Vs);
+check_strict_value_termorder([_]) -> true.
%%%
%%% Binary matching.