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authorJohn Högberg <[email protected]>2019-02-08 15:15:54 +0100
committerJohn Högberg <[email protected]>2019-02-18 11:29:06 +0100
commit6ae2fa3f49e7f4a3cd228dce072065bdc516d62a (patch)
treee8fa003b4b199633bdb56726c25d23712a7b8eee /lib/compiler
parent0610566c58fdebb8f2fa2ffe5196278fc6052d10 (diff)
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beam_validator: Infer BIF argument types
If we know that a BIF will badarg unless its arguments have certain types, we can infer that we have at least those types on success. Note that we can't do this in the general case as the BIF could fail for reasons other than bad arguments.
Diffstat (limited to 'lib/compiler')
-rw-r--r--lib/compiler/src/beam_validator.erl59
1 files changed, 52 insertions, 7 deletions
diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl
index 984d668532..4f5818ae9f 100644
--- a/lib/compiler/src/beam_validator.erl
+++ b/lib/compiler/src/beam_validator.erl
@@ -28,7 +28,7 @@
-export([module/2, format_error/1]).
-export([type_anno/1, type_anno/2, type_anno/4]).
--import(lists, [any/2,dropwhile/2,foldl/3,map/2,reverse/1]).
+-import(lists, [any/2,dropwhile/2,foldl/3,map/2,reverse/1,zip/2]).
%% To be called by the compiler.
@@ -639,7 +639,15 @@ valfun_4({bif,Op,{f,Fail},[Cons]=Ss,Dst}, Vst0)
extract_term(Type, Ss, Dst, Vst);
valfun_4({bif,Op,{f,Fail},Ss,Dst}, Vst0) ->
validate_src(Ss, Vst0),
- Vst = branch_state(Fail, Vst0),
+ Vst1 = branch_state(Fail, Vst0),
+
+ %% Infer argument types. Note that we can't type_test in the general case
+ %% as the BIF could fail for reasons other than bad arguments.
+ ArgTypes = bif_arg_types(Op, Ss),
+ Vst = foldl(fun({Arg, T}, Vsti) ->
+ update_type(fun meet/2, T, Arg, Vsti)
+ end, Vst1, zip(Ss, ArgTypes)),
+
Type = bif_type(Op, Ss, Vst),
extract_term(Type, Ss, Dst, Vst);
valfun_4({gc_bif,Op,{f,Fail},Live,Ss,Dst}, #vst{current=St0}=Vst0) ->
@@ -649,11 +657,12 @@ valfun_4({gc_bif,Op,{f,Fail},Live,Ss,Dst}, #vst{current=St0}=Vst0) ->
St = kill_heap_allocation(St0),
Vst1 = Vst0#vst{current=St},
Vst2 = branch_state(Fail, Vst1),
- Vst3 = case Op of
- length -> update_type(fun meet/2, list, hd(Ss), Vst2);
- map_size -> update_type(fun meet/2, map, hd(Ss), Vst2);
- _ -> Vst2
- end,
+
+ ArgTypes = bif_arg_types(Op, Ss),
+ Vst3 = foldl(fun({Arg, T}, Vsti) ->
+ update_type(fun meet/2, T, Arg, Vsti)
+ end, Vst2, zip(Ss, ArgTypes)),
+
Type = bif_type(Op, Ss, Vst3),
Vst = prune_x_regs(Live, Vst3),
extract_term(Type, Ss, Dst, Vst, Vst0);
@@ -2187,6 +2196,42 @@ propagate_fragility(Type, Ss, Vst) ->
false -> Type
end.
+%% Generic
+bif_arg_types(tuple_size, [_]) -> [{tuple,[0],#{}}];
+bif_arg_types(map_size, [_]) -> [map];
+bif_arg_types(length, [_]) -> [list];
+bif_arg_types(hd, [_]) -> [cons];
+bif_arg_types(tl, [_]) -> [cons];
+%% Boolean
+bif_arg_types('not', [_]) -> [bool];
+bif_arg_types('and', [_,_]) -> [bool, bool];
+bif_arg_types('or', [_,_]) -> [bool, bool];
+bif_arg_types('xor', [_,_]) -> [bool, bool];
+%% Binary
+bif_arg_types('byte_size', [_]) -> [binary];
+bif_arg_types('bit_size', [_]) -> [binary];
+%% Numerical
+bif_arg_types('-', [_]) -> [number];
+bif_arg_types('+', [_]) -> [number];
+bif_arg_types('*', [_,_]) -> [number, number];
+bif_arg_types('/', [_,_]) -> [number, number];
+bif_arg_types(ceil, [_]) -> [number];
+bif_arg_types(floor, [_]) -> [number];
+bif_arg_types(trunc, [_]) -> [number];
+bif_arg_types(round, [_]) -> [number];
+%% Integer-specific
+bif_arg_types('div', [_,_]) -> [{integer,[]}, {integer,[]}];
+bif_arg_types('rem', [_,_]) -> [{integer,[]}, {integer,[]}];
+bif_arg_types('band', [_,_]) -> [{integer,[]}, {integer,[]}];
+bif_arg_types('bor', [_,_]) -> [{integer,[]}, {integer,[]}];
+bif_arg_types('bxor', [_,_]) -> [{integer,[]}, {integer,[]}];
+bif_arg_types('bnot', [_]) -> [{integer,[]}];
+bif_arg_types('bsl', [_,_]) -> [{integer,[]}, {integer,[]}];
+bif_arg_types('bsr', [_,_]) -> [{integer,[]}, {integer,[]}];
+%% Unsafe type tests that may fail if an argument doesn't have the right type.
+bif_arg_types(is_function, [_,_]) -> [term, {integer,[]}];
+bif_arg_types(_, Args) -> [term || _Arg <- Args].
+
bif_type('-', Src, Vst) ->
arith_type(Src, Vst);
bif_type('+', Src, Vst) ->