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-rw-r--r--lib/compiler/src/beam_utils.erl103
1 files changed, 42 insertions, 61 deletions
diff --git a/lib/compiler/src/beam_utils.erl b/lib/compiler/src/beam_utils.erl
index 37f89dd677..47703b4aa3 100644
--- a/lib/compiler/src/beam_utils.erl
+++ b/lib/compiler/src/beam_utils.erl
@@ -25,9 +25,8 @@
is_not_used/3,is_not_used_at/3,
empty_label_index/0,index_label/3,index_labels/1,
code_at/2,bif_to_test/3,is_pure_test/1,
- live_opt/1,delete_live_annos/1,combine_heap_needs/2]).
-
--export([join_even/2,split_even/1]).
+ live_opt/1,delete_live_annos/1,combine_heap_needs/2,
+ join_even/2,split_even/1]).
-import(lists, [member/2,sort/1,reverse/1,splitwith/2]).
@@ -67,8 +66,7 @@ is_killed(R, Is, D) ->
St = #live{bl=check_killed_block_fun(),lbl=D,res=gb_trees:empty()},
case check_liveness(R, Is, St) of
{killed,_} -> true;
- {used,_} -> false;
- {unknown,_} -> false
+ {used,_} -> false
end.
%% is_killed_at(Reg, Lbl, State) -> true|false
@@ -78,8 +76,7 @@ is_killed_at(R, Lbl, D) when is_integer(Lbl) ->
St0 = #live{bl=check_killed_block_fun(),lbl=D,res=gb_trees:empty()},
case check_liveness_at(R, Lbl, St0) of
{killed,_} -> true;
- {used,_} -> false;
- {unknown,_} -> false
+ {used,_} -> false
end.
%% is_not_used(Register, [Instruction], State) -> true|false
@@ -93,8 +90,7 @@ is_not_used(R, Is, D) ->
St = #live{bl=fun check_used_block/3,lbl=D,res=gb_trees:empty()},
case check_liveness(R, Is, St) of
{killed,_} -> true;
- {used,_} -> false;
- {unknown,_} -> false
+ {used,_} -> false
end.
%% is_not_used(Register, [Instruction], State) -> true|false
@@ -108,8 +104,7 @@ is_not_used_at(R, Lbl, D) ->
St = #live{bl=fun check_used_block/3,lbl=D,res=gb_trees:empty()},
case check_liveness_at(R, Lbl, St) of
{killed,_} -> true;
- {used,_} -> false;
- {unknown,_} -> false
+ {used,_} -> false
end.
%% index_labels(FunctionIs) -> State
@@ -137,10 +132,7 @@ index_label(Lbl, Is0, Acc) ->
%% Retrieve the code at the given label.
code_at(L, Ll) ->
- case gb_trees:lookup(L, Ll) of
- {value,Code} -> Code;
- none -> none
- end.
+ gb_trees:get(L, Ll).
%% bif_to_test(Bif, [Op], Fail) -> {test,Test,Fail,[Op]}
%% Convert a BIF to a test. Fail if not possible.
@@ -164,10 +156,10 @@ bif_to_test('=<', [A,B], Fail) -> {test,is_ge,Fail,[B,A]};
bif_to_test('>', [A,B], Fail) -> {test,is_lt,Fail,[B,A]};
bif_to_test('<', [_,_]=Ops, Fail) -> {test,is_lt,Fail,Ops};
bif_to_test('>=', [_,_]=Ops, Fail) -> {test,is_ge,Fail,Ops};
-bif_to_test('==', [A,[]], Fail) -> {test,is_nil,Fail,[A]};
+bif_to_test('==', [A,nil], Fail) -> {test,is_nil,Fail,[A]};
bif_to_test('==', [_,_]=Ops, Fail) -> {test,is_eq,Fail,Ops};
bif_to_test('/=', [_,_]=Ops, Fail) -> {test,is_ne,Fail,Ops};
-bif_to_test('=:=', [A,[]], Fail) -> {test,is_nil,Fail,[A]};
+bif_to_test('=:=', [A,nil], Fail) -> {test,is_nil,Fail,[A]};
bif_to_test('=:=', [_,_]=Ops, Fail) -> {test,is_eq_exact,Fail,Ops};
bif_to_test('=/=', [_,_]=Ops, Fail) -> {test,is_ne_exact,Fail,Ops};
bif_to_test(is_record, [_,_,_]=Ops, Fail) -> {test,is_record,Fail,Ops}.
@@ -235,21 +227,28 @@ combine_heap_needs(Words, {alloc,Alloc}) when is_integer(Words) ->
combine_heap_needs(H1, H2) when is_integer(H1), is_integer(H2) ->
H1+H2.
+%% split_even/1
+%% [1,2,3,4,5,6] -> {[1,3,5],[2,4,6]}
+
+split_even(Rs) -> split_even(Rs, [], []).
+
+%% join_even/1
+%% {[1,3,5],[2,4,6]} -> [1,2,3,4,5,6]
+
+join_even([], []) -> [];
+join_even([S|Ss], [D|Ds]) -> [S,D|join_even(Ss, Ds)].
+
%%%
%%% Local functions.
%%%
-%% check_liveness(Reg, [Instruction], {State,BlockCheckFun}) ->
-%% {killed | used | unknown,UpdateState}
-%% Finds out how Reg is used in the instruction sequence. Returns one of:
-%% killed - Reg is assigned a new value or killed by an allocation instruction
-%% used - Reg is used (or possibly referenced by an allocation instruction)
-%% unknown - not possible to determine (perhaps because of an instruction
-%% that we don't recognize)
+%% check_liveness(Reg, [Instruction], #live{}) ->
+%% {killed | used, #live{}}
+%% Find out whether Reg is used or killed in instruction sequence.
+%% 'killed' means that Reg is assigned a new value or killed by an
+%% allocation instruction. 'used' means that Reg is used in some way.
-check_liveness(R, [{set,_,_,_}=I|_], St) ->
- erlang:error(only_allowed_in_blocks, [R,I,St]);
check_liveness(R, [{block,Blk}|Is], #live{bl=BlockCheck}=St0) ->
case BlockCheck(R, Blk, St0) of
{transparent,St} -> check_liveness(R, Is, St);
@@ -461,8 +460,9 @@ check_liveness(R, [{loop_rec,{f,_},{x,0}}|_], St) ->
{x,_} ->
{killed,St};
_ ->
- %% y register. Rarely happens. Be very conversative.
- {unknown,St}
+ %% y register. Rarely happens. Be very conversative and
+ %% assume it's used.
+ {used,St}
end;
check_liveness(R, [{loop_rec_end,{f,Fail}}|_], St) ->
check_liveness_at(R, Fail, St);
@@ -493,7 +493,8 @@ check_liveness(R, [{put_map,{f,_},_,Src,_D,Live,{list,_}}|_], St0) ->
{x,_} ->
{killed,St0};
{y,_} ->
- {unknown,St0}
+ %% Conservatively mark it as used.
+ {used,St0}
end;
check_liveness(R, [{test_heap,N,Live}|Is], St) ->
I = {block,[{set,[],[],{alloc,Live,{nozero,nostack,N,[]}}}]},
@@ -505,12 +506,8 @@ check_liveness(R, [{get_list,S,D1,D2}|Is], St) ->
I = {block,[{set,[D1,D2],[S],get_list}]},
check_liveness(R, [I|Is], St);
check_liveness(_R, Is, St) when is_list(Is) ->
-%% case Is of
-%% [I|_] ->
-%% io:format("~p ~p\n", [_R,I]);
-%% _ -> ok
-%% end,
- {unknown,St}.
+ %% Not implemented. Conservatively assume that the register is used.
+ {used,St}.
check_liveness_everywhere(R, [{f,Lbl}|T], St0) ->
case check_liveness_at(R, Lbl, St0) of
@@ -529,7 +526,7 @@ check_liveness_at(R, Lbl, #live{lbl=Ll,res=ResMemorized}=St0) ->
none ->
{Res,St} = case gb_trees:lookup(Lbl, Ll) of
{value,Is} -> check_liveness(R, Is, St0);
- none -> {unknown,St0}
+ none -> {used,St0}
end,
{Res,St#live{res=gb_trees:insert(Lbl, Res, St#live.res)}}
end.
@@ -594,8 +591,10 @@ check_killed_block(_, []) -> transparent.
%% killed - Reg is assigned a new value or killed by an allocation instruction
%% transparent - Reg is neither used nor killed
%% used - Reg is explicitly used by an instruction
-%%
-%% (Unknown instructions will cause an exception.)
+%%
+%% '%live' annotations are not allowed.
+%%
+%% (Unknown instructions will cause an exception.)
check_used_block({x,X}=R, [{set,Ds,Ss,{alloc,Live,Op}}|Is], St) ->
if
@@ -604,11 +603,6 @@ check_used_block({x,X}=R, [{set,Ds,Ss,{alloc,Live,Op}}|Is], St) ->
end;
check_used_block(R, [{set,Ds,Ss,Op}|Is], St) ->
check_used_block_1(R, Ss, Ds, Op, Is, St);
-check_used_block(R, [{'%live',Live,_}|Is], St) ->
- case R of
- {x,X} when X >= Live -> {killed,St};
- _ -> check_used_block(R, Is, St)
- end;
check_used_block(_, [], St) -> {transparent,St}.
check_used_block_1(R, Ss, Ds, Op, Is, St0) ->
@@ -639,8 +633,7 @@ is_reg_used_at_1(_, 0, St) ->
is_reg_used_at_1(R, Lbl, St0) ->
case check_liveness_at(R, Lbl, St0) of
{killed,St} -> {false,St};
- {used,St} -> {true,St};
- {unknown,St} -> {true,St}
+ {used,St} -> {true,St}
end.
index_labels_1([{label,Lbl}|Is0], Acc) ->
@@ -756,11 +749,6 @@ live_opt([{select,_,Src,Fail,List}=I|Is], Regs0, D, Acc) ->
Regs1 = x_live([Src], Regs0),
Regs = live_join_labels([Fail|List], D, Regs1),
live_opt(Is, Regs, D, [I|Acc]);
-live_opt([{'try',_,_}=I|Is], Regs, D, Acc) ->
- %% If an exeption happens, all x registers will be killed.
- %% Therefore, we should only base liveness of the code inside
- %% the try.
- live_opt(Is, Regs, D, [I|Acc]);
live_opt([{try_case,_}=I|Is], _, D, Acc) ->
live_opt(Is, live_call(1), D, [I|Acc]);
live_opt([{loop_rec,_Fail,_Dst}=I|Is], _, D, Acc) ->
@@ -860,14 +848,7 @@ x_live([], Regs) -> Regs.
is_live(X, Regs) -> ((Regs bsr X) band 1) =:= 1.
-%% split_even/1
-%% [1,2,3,4,5,6] -> {[1,3,5],[2,4,6]}
-split_even(Rs) -> split_even(Rs,[],[]).
-split_even([],Ss,Ds) -> {reverse(Ss),reverse(Ds)};
-split_even([S,D|Rs],Ss,Ds) ->
- split_even(Rs,[S|Ss],[D|Ds]).
-
-%% join_even/1
-%% {[1,3,5],[2,4,6]} -> [1,2,3,4,5,6]
-join_even([],[]) -> [];
-join_even([S|Ss],[D|Ds]) -> [S,D|join_even(Ss,Ds)].
+split_even([], Ss, Ds) ->
+ {reverse(Ss),reverse(Ds)};
+split_even([S,D|Rs], Ss, Ds) ->
+ split_even(Rs, [S|Ss], [D|Ds]).
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-08 22:37:52 +0000