aboutsummaryrefslogtreecommitdiffstats
path: root/lib/compiler/src/beam_utils.erl
diff options
context:
space:
mode:
Diffstat (limited to 'lib/compiler/src/beam_utils.erl')
-rw-r--r--lib/compiler/src/beam_utils.erl404
1 files changed, 370 insertions, 34 deletions
diff --git a/lib/compiler/src/beam_utils.erl b/lib/compiler/src/beam_utils.erl
index e39fbdc3b7..e61d6a43b4 100644
--- a/lib/compiler/src/beam_utils.erl
+++ b/lib/compiler/src/beam_utils.erl
@@ -22,15 +22,23 @@
-module(beam_utils).
-export([is_killed_block/2,is_killed/3,is_killed_at/3,
- is_not_used/3,
- empty_label_index/0,index_label/3,index_labels/1,
+ is_not_used/3,usage/3,
+ empty_label_index/0,index_label/3,index_labels/1,replace_labels/4,
code_at/2,bif_to_test/3,is_pure_test/1,
live_opt/1,delete_live_annos/1,combine_heap_needs/2,
- split_even/1]).
+ anno_defs/1,
+ split_even/1
+ ]).
-export_type([code_index/0,module_code/0,instruction/0]).
--import(lists, [member/2,sort/1,reverse/1,splitwith/2]).
+-import(lists, [flatmap/2,map/2,member/2,sort/1,reverse/1,splitwith/2]).
+
+-define(is_const(Val), (Val =:= nil orelse
+ element(1, Val) =:= integer orelse
+ element(1, Val) =:= float orelse
+ element(1, Val) =:= atom orelse
+ element(1, Val) =:= literal)).
%% instruction() describes all instructions that are used during optimzation
%% (from beam_a to beam_z).
@@ -54,6 +62,23 @@
{lbl :: code_index(), %Label to code index.
res :: result_cache()}). %Result cache for each label.
+%% usage(Register, [Instruction], State) -> killed|not_used|used.
+%% Determine the usage of Register in the instruction sequence.
+%% The return value is one of:
+%%
+%% killed - The register is not used in any way.
+%% not_used - The register is referenced only by an allocating instruction
+%% (the actual value does not matter).
+%% used - The register is used (its value do matter).
+
+-spec usage(beam_asm:reg(), [instruction()], code_index()) ->
+ 'killed' | 'not_used' | 'used'.
+
+usage(R, Is, D) ->
+ St = #live{lbl=D,res=gb_trees:empty()},
+ {Usage,_} = check_liveness(R, Is, St),
+ Usage.
+
%% is_killed_block(Register, [Instruction]) -> true|false
%% Determine whether a register is killed by the instruction sequence inside
@@ -160,6 +185,18 @@ index_label(Lbl, Is0, Acc) ->
code_at(L, Ll) ->
gb_trees:get(L, Ll).
+%% replace_labels(FunctionIs, Tail, ReplaceDb, Fallback) -> FunctionIs.
+%% Replace all labels in instructions according to the ReplaceDb.
+%% If label is not found the Fallback is called with the label to
+%% produce a new one.
+
+-spec replace_labels([instruction()],
+ [instruction()],
+ #{beam_asm:label() => beam_asm:label()},
+ fun((beam_asm:label()) -> term())) -> [instruction()].
+replace_labels(Is, Acc, D, Fb) ->
+ replace_labels_1(Is, Acc, D, Fb).
+
%% bif_to_test(Bif, [Op], Fail) -> {test,Test,Fail,[Op]}
%% Convert a BIF to a test. Fail if not possible.
@@ -185,10 +222,20 @@ 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,nil], Fail) -> {test,is_nil,Fail,[A]};
+bif_to_test('==', [nil,A], Fail) -> {test,is_nil,Fail,[A]};
+bif_to_test('==', [C,A], Fail) when ?is_const(C) ->
+ {test,is_eq,Fail,[A,C]};
bif_to_test('==', [_,_]=Ops, Fail) -> {test,is_eq,Fail,Ops};
+bif_to_test('/=', [C,A], Fail) when ?is_const(C) ->
+ {test,is_ne,Fail,[A,C]};
bif_to_test('/=', [_,_]=Ops, Fail) -> {test,is_ne,Fail,Ops};
bif_to_test('=:=', [A,nil], Fail) -> {test,is_nil,Fail,[A]};
+bif_to_test('=:=', [nil,A], Fail) -> {test,is_nil,Fail,[A]};
+bif_to_test('=:=', [C,A], Fail) when ?is_const(C) ->
+ {test,is_eq_exact,Fail,[A,C]};
bif_to_test('=:=', [_,_]=Ops, Fail) -> {test,is_eq_exact,Fail,Ops};
+bif_to_test('=/=', [C,A], Fail) when ?is_const(C) ->
+ {test,is_ne_exact,Fail,[A,C]};
bif_to_test('=/=', [_,_]=Ops, Fail) -> {test,is_ne_exact,Fail,Ops};
bif_to_test(is_record, [_,_,_]=Ops, Fail) -> {test,is_record,Fail,Ops}.
@@ -254,16 +301,33 @@ delete_live_annos([]) -> [].
%% combine_heap_needs(HeapNeed1, HeapNeed2) -> HeapNeed
%% Combine the heap need for two allocation instructions.
--spec combine_heap_needs(term(), term()) -> term().
+-type heap_need_tag() :: 'floats' | 'words'.
+-type heap_need() :: non_neg_integer() |
+ {'alloc',[{heap_need_tag(),non_neg_integer()}]}.
+-spec combine_heap_needs(heap_need(), heap_need()) -> heap_need().
-combine_heap_needs({alloc,Alloc1}, {alloc,Alloc2}) ->
- {alloc,combine_alloc_lists(Alloc1, Alloc2)};
-combine_heap_needs({alloc,Alloc}, Words) when is_integer(Words) ->
- {alloc,combine_alloc_lists(Alloc, [{words,Words}])};
-combine_heap_needs(Words, {alloc,Alloc}) when is_integer(Words) ->
- {alloc,combine_alloc_lists(Alloc, [{words,Words}])};
combine_heap_needs(H1, H2) when is_integer(H1), is_integer(H2) ->
- H1+H2.
+ H1 + H2;
+combine_heap_needs(H1, H2) ->
+ combine_alloc_lists([H1,H2]).
+
+
+%% anno_defs(Instructions) -> Instructions'
+%% Add {'%def',RegisterBitmap} annotations to the beginning of
+%% each block. Iff bit X is set in the the bitmap, it means
+%% that {x,X} is defined when the block is entered.
+
+-spec anno_defs([instruction()]) -> [instruction()].
+
+anno_defs(Is0) ->
+ {Bef,[Fi|Is1]} =
+ splitwith(fun({func_info,_,_,_}) -> false;
+ (_) -> true
+ end, Is0),
+ {func_info,_,_,Arity} = Fi,
+ Regs = init_def_regs(Arity),
+ Is = defs(Is1, Regs, #{}),
+ Bef ++ [Fi|Is].
%% split_even/1
%% [1,2,3,4,5,6] -> {[1,3,5],[2,4,6]}
@@ -272,7 +336,6 @@ combine_heap_needs(H1, H2) when is_integer(H1), is_integer(H2) ->
split_even(Rs) -> split_even(Rs, [], []).
-
%%%
%%% Local functions.
%%%
@@ -290,6 +353,10 @@ check_liveness(R, [{block,Blk}|Is], St0) ->
case check_liveness_block(R, Blk, St0) of
{transparent,St1} ->
check_liveness(R, Is, St1);
+ {alloc_used,St1} ->
+ %% Used by an allocating instruction, but value not referenced.
+ %% Must check the rest of the instructions.
+ not_used(check_liveness(R, Is, St1));
{Other,_}=Res when is_atom(Other) ->
Res
end;
@@ -348,9 +415,16 @@ check_liveness(R, [{bs_init,_,_,none,Ss,Dst}|Is], St) ->
check_liveness(R, [{bs_init,_,_,Live,Ss,Dst}|Is], St) ->
case R of
{x,X} ->
- case X < Live orelse member(R, Ss) of
- true -> {used,St};
- false -> {killed,St}
+ case member(R, Ss) of
+ true ->
+ {used,St};
+ false ->
+ if
+ X < Live ->
+ not_used(check_liveness(R, Is, St));
+ true ->
+ {killed,St}
+ end
end;
{y,_} ->
case member(R, Ss) of
@@ -560,7 +634,7 @@ check_liveness_ret(R, R, St) -> {used,St};
check_liveness_ret(_, _, St) -> {killed,St}.
%% check_liveness_block(Reg, [Instruction], State) ->
-%% {killed | not_used | used | transparent,State'}
+%% {killed | not_used | used | alloc_used | transparent,State'}
%% Finds out how Reg is used in the instruction sequence inside a block.
%% Returns one of:
%% killed - Reg is assigned a new value or killed by an
@@ -568,6 +642,7 @@ check_liveness_ret(_, _, St) -> {killed,St}.
%% not_used - The value is not used, but the register is referenced
%% e.g. by an allocation instruction
%% transparent - Reg is neither used nor killed
+%% alloc_used - Used only in an allocate instruction
%% used - Reg is explicitly used by an instruction
%%
%% '%live' annotations are not allowed.
@@ -581,7 +656,7 @@ check_liveness_block({x,X}=R, [{set,Ds,Ss,{alloc,Live,Op}}|Is], St0) ->
true ->
case check_liveness_block_1(R, Ss, Ds, Op, Is, St0) of
{killed,St} -> {not_used,St};
- {transparent,St} -> {not_used,St};
+ {transparent,St} -> {alloc_used,St};
{_,_}=Res -> Res
end
end;
@@ -643,22 +718,70 @@ index_labels_1([], Acc) -> gb_trees:from_orddict(sort(Acc)).
drop_labels([{label,_}|Is]) -> drop_labels(Is);
drop_labels(Is) -> Is.
-%% Help functions for combine_heap_needs.
-combine_alloc_lists(Al1, Al2) ->
- combine_alloc_lists_1(sort(Al1++Al2)).
+replace_labels_1([{test,Test,{f,Lbl},Ops}|Is], Acc, D, Fb) ->
+ replace_labels_1(Is, [{test,Test,{f,label(Lbl, D, Fb)},Ops}|Acc], D, Fb);
+replace_labels_1([{test,Test,{f,Lbl},Live,Ops,Dst}|Is], Acc, D, Fb) ->
+ replace_labels_1(Is, [{test,Test,{f,label(Lbl, D, Fb)},Live,Ops,Dst}|Acc], D, Fb);
+replace_labels_1([{select,I,R,{f,Fail0},Vls0}|Is], Acc, D, Fb) ->
+ Vls = map(fun ({f,L}) -> {f,label(L, D, Fb)};
+ (Other) -> Other
+ end, Vls0),
+ Fail = label(Fail0, D, Fb),
+ replace_labels_1(Is, [{select,I,R,{f,Fail},Vls}|Acc], D, Fb);
+replace_labels_1([{'try',R,{f,Lbl}}|Is], Acc, D, Fb) ->
+ replace_labels_1(Is, [{'try',R,{f,label(Lbl, D, Fb)}}|Acc], D, Fb);
+replace_labels_1([{'catch',R,{f,Lbl}}|Is], Acc, D, Fb) ->
+ replace_labels_1(Is, [{'catch',R,{f,label(Lbl, D, Fb)}}|Acc], D, Fb);
+replace_labels_1([{jump,{f,Lbl}}|Is], Acc, D, Fb) ->
+ replace_labels_1(Is, [{jump,{f,label(Lbl, D, Fb)}}|Acc], D, Fb);
+replace_labels_1([{loop_rec,{f,Lbl},R}|Is], Acc, D, Fb) ->
+ replace_labels_1(Is, [{loop_rec,{f,label(Lbl, D, Fb)},R}|Acc], D, Fb);
+replace_labels_1([{loop_rec_end,{f,Lbl}}|Is], Acc, D, Fb) ->
+ replace_labels_1(Is, [{loop_rec_end,{f,label(Lbl, D, Fb)}}|Acc], D, Fb);
+replace_labels_1([{wait,{f,Lbl}}|Is], Acc, D, Fb) ->
+ replace_labels_1(Is, [{wait,{f,label(Lbl, D, Fb)}}|Acc], D, Fb);
+replace_labels_1([{wait_timeout,{f,Lbl},To}|Is], Acc, D, Fb) ->
+ replace_labels_1(Is, [{wait_timeout,{f,label(Lbl, D, Fb)},To}|Acc], D, Fb);
+replace_labels_1([{bif,Name,{f,Lbl},As,R}|Is], Acc, D, Fb) when Lbl =/= 0 ->
+ replace_labels_1(Is, [{bif,Name,{f,label(Lbl, D, Fb)},As,R}|Acc], D, Fb);
+replace_labels_1([{gc_bif,Name,{f,Lbl},Live,As,R}|Is], Acc, D, Fb) when Lbl =/= 0 ->
+ replace_labels_1(Is, [{gc_bif,Name,{f,label(Lbl, D, Fb)},Live,As,R}|Acc], D, Fb);
+replace_labels_1([{call,Ar,{f,Lbl}}|Is], Acc, D, Fb) ->
+ replace_labels_1(Is, [{call,Ar,{f,label(Lbl, D, Fb)}}|Acc], D, Fb);
+replace_labels_1([{make_fun2,{f,Lbl},U1,U2,U3}|Is], Acc, D, Fb) ->
+ replace_labels_1(Is, [{make_fun2,{f,label(Lbl, D, Fb)},U1,U2,U3}|Acc], D, Fb);
+replace_labels_1([{bs_init,{f,Lbl},Info,Live,Ss,Dst}|Is], Acc, D, Fb) when Lbl =/= 0 ->
+ replace_labels_1(Is, [{bs_init,{f,label(Lbl, D, Fb)},Info,Live,Ss,Dst}|Acc], D, Fb);
+replace_labels_1([{bs_put,{f,Lbl},Info,Ss}|Is], Acc, D, Fb) when Lbl =/= 0 ->
+ replace_labels_1(Is, [{bs_put,{f,label(Lbl, D, Fb)},Info,Ss}|Acc], D, Fb);
+replace_labels_1([{put_map=I,{f,Lbl},Op,Src,Dst,Live,List}|Is], Acc, D, Fb)
+ when Lbl =/= 0 ->
+ replace_labels_1(Is, [{I,{f,label(Lbl, D, Fb)},Op,Src,Dst,Live,List}|Acc], D, Fb);
+replace_labels_1([{get_map_elements=I,{f,Lbl},Src,List}|Is], Acc, D, Fb) when Lbl =/= 0 ->
+ replace_labels_1(Is, [{I,{f,label(Lbl, D, Fb)},Src,List}|Acc], D, Fb);
+replace_labels_1([I|Is], Acc, D, Fb) ->
+ replace_labels_1(Is, [I|Acc], D, Fb);
+replace_labels_1([], Acc, _, _) -> Acc.
+
+label(Old, D, Fb) ->
+ case D of
+ #{Old := New} -> New;
+ _ -> Fb(Old)
+ end.
-combine_alloc_lists_1([{words,W1},{words,W2}|T])
- when is_integer(W1), is_integer(W2) ->
- [{words,W1+W2}|combine_alloc_lists_1(T)];
-combine_alloc_lists_1([{floats,F1},{floats,F2}|T])
- when is_integer(F1), is_integer(F2) ->
- [{floats,F1+F2}|combine_alloc_lists_1(T)];
-combine_alloc_lists_1([{words,_}=W|T]) ->
- [W|combine_alloc_lists_1(T)];
-combine_alloc_lists_1([{floats,_}=F|T]) ->
- [F|combine_alloc_lists_1(T)];
-combine_alloc_lists_1([]) -> [].
+%% Help function for combine_heap_needs.
+
+combine_alloc_lists(Al0) ->
+ Al1 = flatmap(fun(Words) when is_integer(Words) ->
+ [{words,Words}];
+ ({alloc,List}) ->
+ List
+ end, Al0),
+ Al2 = sofs:relation(Al1),
+ Al3 = sofs:relation_to_family(Al2),
+ Al4 = sofs:to_external(Al3),
+ [{Tag,lists:sum(L)} || {Tag,L} <- Al4].
%% live_opt/4.
@@ -701,6 +824,8 @@ live_opt([{block,Bl0}|Is], Regs0, D, Acc) ->
{Bl,Regs} = live_opt_block(reverse(Bl0), Regs0, D, [Live0]),
Live = {'%live',live_regs(Regs),Regs},
live_opt(Is, Regs, D, [{block,[Live|Bl]}|Acc]);
+live_opt([build_stacktrace=I|Is], _, D, Acc) ->
+ live_opt(Is, live_call(1), D, [I|Acc]);
live_opt([{label,L}=I|Is], Regs, D0, Acc) ->
D = gb_trees:insert(L, Regs, D0),
live_opt(Is, Regs, D, [I|Acc]);
@@ -746,8 +871,14 @@ 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_case,_}=I|Is], _, D, Acc) ->
- live_opt(Is, live_call(1), D, [I|Acc]);
+live_opt([{try_case,Y}=I|Is], Regs0, D, Acc) ->
+ Regs = live_call(1),
+ case Regs0 of
+ 0 ->
+ live_opt(Is, Regs, D, [{try_end,Y}|Acc]);
+ _ ->
+ live_opt(Is, live_call(1), D, [I|Acc])
+ end;
live_opt([{loop_rec,_Fail,_Dst}=I|Is], _, D, Acc) ->
live_opt(Is, 0, D, [I|Acc]);
live_opt([timeout=I|Is], _, D, Acc) ->
@@ -865,3 +996,208 @@ split_even([], Ss, Ds) ->
{reverse(Ss),reverse(Ds)};
split_even([S,D|Rs], Ss, Ds) ->
split_even(Rs, [S|Ss], [D|Ds]).
+
+%%%
+%%% Add annotations for defined registers.
+%%%
+%%% This analysis is done by scanning the instructions in
+%%% execution order.
+%%%
+
+defs([{apply,_}=I|Is], _Regs, D) ->
+ [I|defs(Is, 1, D)];
+defs([{bif,_,{f,Fail},_Src,Dst}=I|Is], Regs0, D) ->
+ Regs = def_regs([Dst], Regs0),
+ [I|defs(Is, Regs, update_regs(Fail, Regs0, D))];
+defs([{block,Block0}|Is], Regs0, D0) ->
+ {Block,Regs,D} = defs_list(Block0, Regs0, D0),
+ [{block,[{'%def',Regs0}|Block]}|defs(Is, Regs, D)];
+defs([{bs_init,{f,L},_,_,_,Dst}=I|Is], Regs0, D) ->
+ Regs = def_regs([Dst], Regs0),
+ [I|defs(Is, Regs, update_regs(L, Regs, D))];
+defs([{bs_put,{f,L},_,_}=I|Is], Regs, D) ->
+ [I|defs(Is, Regs, update_regs(L, Regs, D))];
+defs([build_stacktrace=I|Is], _Regs, D) ->
+ [I|defs(Is, 1, D)];
+defs([{call,_,_}=I|Is], _Regs, D) ->
+ [I|defs(Is, 1, D)];
+defs([{call_ext,_,{extfunc,M,F,A}}=I|Is], _Regs, D) ->
+ case erl_bifs:is_exit_bif(M, F, A) of
+ false ->
+ [I|defs(Is, 1, D)];
+ true ->
+ [I|defs_unreachable(Is, D)]
+ end;
+defs([{call_ext,_,_}=I|Is], _Regs, D) ->
+ [I|defs(Is, 1, D)];
+defs([{call_fun,_}=I|Is], _Regs, D) ->
+ [I|defs(Is, 1, D)];
+defs([{'catch',_,{f,L}}=I|Is], Regs, D) ->
+ RegsAtLabel = init_def_regs(1),
+ [I|defs(Is, Regs, update_regs(L, RegsAtLabel, D))];
+defs([{catch_end,_}=I|Is], _Regs, D) ->
+ Regs = init_def_regs(1),
+ [I|defs(Is, Regs, D)];
+defs([{gc_bif,_,{f,Fail},Live,_Src,Dst}=I|Is], Regs0, D) ->
+ true = all_defined(Live, Regs0), %Assertion.
+ Regs = def_regs([Dst], init_def_regs(Live)),
+ [I|defs(Is, Regs, update_regs(Fail, Regs0, D))];
+defs([{get_map_elements,{f,L},_Src,{list,DstList}}=I|Is], Regs0, D) ->
+ {_,Ds} = beam_utils:split_even(DstList),
+ Regs = def_regs(Ds, Regs0),
+ [I|defs(Is, Regs, update_regs(L, Regs0, D))];
+defs([{get_tuple_element,_,_,Dst}=I|Is], Regs0, D) ->
+ Regs = def_regs([Dst], Regs0),
+ [I|defs(Is, Regs, D)];
+defs([{jump,{f,L}}=I|Is], Regs, D) ->
+ [I|defs_unreachable(Is, update_regs(L, Regs, D))];
+defs([{label,L}=I|Is], Regs0, D) ->
+ case D of
+ #{L:=Regs1} ->
+ Regs = Regs0 band Regs1,
+ [I|defs(Is, Regs, D)];
+ #{} ->
+ [I|defs(Is, Regs0, D)]
+ end;
+defs([{loop_rec,{f,L},{x,0}}=I|Is], _Regs, D0) ->
+ RegsAtLabel = init_def_regs(0),
+ D = update_regs(L, RegsAtLabel, D0),
+ [I|defs(Is, init_def_regs(1), D)];
+defs([{loop_rec_end,_}=I|Is], _Regs, D) ->
+ [I|defs(Is, 0, D)];
+defs([{make_fun2,_,_,_,_}=I|Is], _Regs, D) ->
+ [I|defs(Is, 1, D)];
+defs([{move,_,Dst}=I|Is], Regs0, D) ->
+ Regs = def_regs([Dst], Regs0),
+ [I|defs(Is, Regs, D)];
+defs([{put_map,{f,Fail},_,_,Dst,_,_}=I|Is], Regs0, D) ->
+ Regs = def_regs([Dst], Regs0),
+ [I|defs(Is, Regs, update_regs(Fail, Regs0, D))];
+defs([return=I|Is], _Regs, D) ->
+ [I|defs_unreachable(Is, D)];
+defs([{select,_,_Src,Fail,List}=I|Is], Regs, D0) ->
+ D = update_list([Fail|List], Regs, D0),
+ [I|defs_unreachable(Is, D)];
+defs([{test,_,{f,L},_}=I|Is], Regs, D) ->
+ [I|defs(Is, Regs, update_regs(L, Regs, D))];
+defs([{test,_,{f,L},Live,_,Dst}=I|Is], Regs0, D) ->
+ true = all_defined(Live, Regs0), %Assertion.
+ Regs = def_regs([Dst], init_def_regs(Live)),
+ [I|defs(Is, Regs, update_regs(L, Regs0, D))];
+defs([{'try',_,{f,L}}=I|Is], Regs, D) ->
+ RegsAtLabel = init_def_regs(3),
+ [I|defs(Is, Regs, update_regs(L, RegsAtLabel, D))];
+defs([{try_case,_}=I|Is], _Regs, D) ->
+ [I|defs(Is, init_def_regs(3), D)];
+defs([{wait,_}=I|Is], _Regs, D) ->
+ [I|defs_unreachable(Is, D)];
+defs([{wait_timeout,_,_}=I|Is], _Regs, D) ->
+ [I|defs(Is, 0, D)];
+
+%% Exceptions.
+defs([{badmatch,_}=I|Is], _Regs, D) ->
+ [I|defs_unreachable(Is, D)];
+defs([{case_end,_}=I|Is], _Regs, D) ->
+ [I|defs_unreachable(Is, D)];
+defs([if_end=I|Is], _Regs, D) ->
+ [I|defs_unreachable(Is, D)];
+defs([{try_case_end,_}=I|Is], _Regs, D) ->
+ [I|defs_unreachable(Is, D)];
+
+%% Neutral instructions
+defs([{bs_context_to_binary,_}=I|Is], Regs, D) ->
+ [I|defs(Is, Regs, D)];
+defs([{bs_restore2,_,_}=I|Is], Regs, D) ->
+ [I|defs(Is, Regs, D)];
+defs([{bs_save2,_,_}=I|Is], Regs, D) ->
+ [I|defs(Is, Regs, D)];
+defs([{deallocate,_}=I|Is], Regs, D) ->
+ [I|defs(Is, Regs, D)];
+defs([{kill,_}=I|Is], Regs, D) ->
+ [I|defs(Is, Regs, D)];
+defs([{line,_}=I|Is], Regs, D) ->
+ [I|defs(Is, Regs, D)];
+defs([{recv_mark,_}=I|Is], Regs, D) ->
+ [I|defs(Is, Regs, D)];
+defs([{recv_set,_}=I|Is], Regs, D) ->
+ [I|defs(Is, Regs, D)];
+defs([timeout=I|Is], Regs, D) ->
+ [I|defs(Is, Regs, D)];
+defs([{trim,_,_}=I|Is], Regs, D) ->
+ [I|defs(Is, Regs, D)];
+defs([{try_end,_}=I|Is], Regs, D) ->
+ [I|defs(Is, Regs, D)];
+defs([{'%',_}=I|Is], Regs, D) ->
+ [I|defs(Is, Regs, D)];
+defs([], _, _) -> [].
+
+defs_unreachable([{label,L}=I|Is], D) ->
+ case D of
+ #{L:=Regs} ->
+ [I|defs(Is, Regs, D)];
+ #{} ->
+ defs_unreachable(Is, D)
+ end;
+defs_unreachable([_|Is], D) ->
+ defs_unreachable(Is, D);
+defs_unreachable([], _D) -> [].
+
+defs_list(Is, Regs, D) ->
+ defs_list(Is, Regs, D, []).
+
+defs_list([{set,Ds,_,{alloc,Live,Info}}=I|Is], Regs0, D0, Acc) ->
+ true = all_defined(Live, Regs0), %Assertion.
+ D = case Info of
+ {gc_bif,_,{f,Fail}} ->
+ update_regs(Fail, Regs0, D0);
+ {put_map,_,{f,Fail}} ->
+ update_regs(Fail, Regs0, D0);
+ _ ->
+ D0
+ end,
+ Regs = def_regs(Ds, init_def_regs(Live)),
+ defs_list(Is, Regs, D, [I|Acc]);
+defs_list([{set,Ds,_,Info}=I|Is], Regs0, D0, Acc) ->
+ D = case Info of
+ {bif,_,{f,Fail}} ->
+ update_regs(Fail, Regs0, D0);
+ {try_catch,'catch',{f,Fail}} ->
+ update_regs(Fail, init_def_regs(1), D0);
+ {try_catch,'try',{f,Fail}} ->
+ update_regs(Fail, init_def_regs(3), D0);
+ _ ->
+ D0
+ end,
+ Regs = def_regs(Ds, Regs0),
+ defs_list(Is, Regs, D, [I|Acc]);
+defs_list([], Regs, D, Acc) ->
+ {reverse(Acc),Regs,D}.
+
+init_def_regs(Arity) ->
+ (1 bsl Arity) - 1.
+
+def_regs([{x,X}|T], Regs) ->
+ def_regs(T, Regs bor (1 bsl X));
+def_regs([_|T], Regs) ->
+ def_regs(T, Regs);
+def_regs([], Regs) -> Regs.
+
+update_list([{f,L}|T], Regs, D0) ->
+ D = update_regs(L, Regs, D0),
+ update_list(T, Regs, D);
+update_list([_|T], Regs, D) ->
+ update_list(T, Regs, D);
+update_list([], _Regs, D) -> D.
+
+update_regs(L, Regs0, D) ->
+ case D of
+ #{L:=Regs1} ->
+ Regs = Regs0 band Regs1,
+ D#{L:=Regs};
+ #{} ->
+ D#{L=>Regs0}
+ end.
+
+all_defined(Live, Regs) ->
+ All = (1 bsl Live) - 1,
+ Regs band All =:= All.