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.erl289
1 files changed, 116 insertions, 173 deletions
diff --git a/lib/compiler/src/beam_utils.erl b/lib/compiler/src/beam_utils.erl
index abcd93f280..8af0447f63 100644
--- a/lib/compiler/src/beam_utils.erl
+++ b/lib/compiler/src/beam_utils.erl
@@ -87,7 +87,7 @@ is_killed_at(R, Lbl, D) when is_integer(Lbl) ->
%% across branches.
is_not_used(R, Is, D) ->
- St = #live{bl=fun check_used_block/2,lbl=D,res=gb_trees:empty()},
+ St = #live{bl=check_used_block_fun(D),lbl=D,res=gb_trees:empty()},
case check_liveness(R, Is, St) of
{killed,_} -> true;
{used,_} -> false;
@@ -102,7 +102,7 @@ is_not_used(R, Is, D) ->
%% across branches.
is_not_used_at(R, Lbl, D) ->
- St = #live{bl=fun check_used_block/2,lbl=D,res=gb_trees:empty()},
+ St = #live{bl=check_used_block_fun(D),lbl=D,res=gb_trees:empty()},
case check_liveness_at(R, Lbl, St) of
{killed,_} -> true;
{used,_} -> false;
@@ -263,26 +263,14 @@ check_liveness(R, [{test,_,{f,Fail},As}|Is], St0) ->
{_,_}=Other -> Other
end
end;
-check_liveness(R, [{test,_,{f,Fail},Live,Ss,_}|Is], St0) ->
- case R of
- {x,X} ->
- case X < Live orelse member(R, Ss) of
- true -> {used,St0};
- false -> check_liveness_at(R, Fail, St0)
- end;
- {y,_} ->
- case check_liveness_at(R, Fail, St0) of
- {killed,St} -> check_liveness(R, Is, St);
- {_,_}=Other -> Other
- end
- end;
-check_liveness(R, [{select_val,R,_,_}|_], St) ->
- {used,St};
-check_liveness(R, [{select_val,_,Fail,{list,Branches}}|_], St) ->
- check_liveness_everywhere(R, [Fail|Branches], St);
-check_liveness(R, [{select_tuple_arity,R,_,_}|_], St) ->
+check_liveness(R, [{test,Op,Fail,Live,Ss,Dst}|Is], St) ->
+ %% Check this instruction as a block to get a less conservative
+ %% result if the caller is is_not_used/3.
+ Block = [{set,[Dst],Ss,{alloc,Live,{bif,Op,Fail}}}],
+ check_liveness(R, [{block,Block}|Is], St);
+check_liveness(R, [{select,_,R,_,_}|_], St) ->
{used,St};
-check_liveness(R, [{select_tuple_arity,_,Fail,{list,Branches}}|_], St) ->
+check_liveness(R, [{select,_,_,Fail,Branches}|_], St) ->
check_liveness_everywhere(R, [Fail|Branches], St);
check_liveness(R, [{jump,{f,F}}|_], St) ->
check_liveness_at(R, F, St);
@@ -301,37 +289,33 @@ check_liveness(R, [{kill,R}|_], St) ->
{killed,St};
check_liveness(R, [{kill,_}|Is], St) ->
check_liveness(R, Is, St);
-check_liveness(R, [bs_init_writable|Is], St) ->
- if
- R =:= {x,0} -> {used,St};
- true -> check_liveness(R, Is, St)
- end;
-check_liveness(R, [{bs_private_append,_,Bits,_,Bin,_,Dst}|Is], St) ->
- case R of
- Bits -> {used,St};
- Bin -> {used,St};
- Dst -> {killed,St};
- _ -> check_liveness(R, Is, St)
+check_liveness(R, [{bs_init,_,_,none,Ss,Dst}|Is], St) ->
+ case member(R, Ss) of
+ true ->
+ {used,St};
+ false ->
+ if
+ R =:= Dst -> {killed,St};
+ true -> check_liveness(R, Is, St)
+ end
end;
-check_liveness(R, [{bs_append,_,Bits,_,_,_,Bin,_,Dst}|Is], St) ->
+check_liveness(R, [{bs_init,_,_,Live,Ss,Dst}|Is], St) ->
case R of
- Bits -> {used,St};
- Bin -> {used,St};
- Dst -> {killed,St};
- _ -> check_liveness(R, Is, St)
- end;
-check_liveness(R, [{bs_init2,_,_,_,_,_,Dst}|Is], St) ->
- if
- R =:= Dst -> {killed,St};
- true -> check_liveness(R, Is, St)
- end;
-check_liveness(R, [{bs_init_bits,_,_,_,_,_,Dst}|Is], St) ->
- if
- R =:= Dst -> {killed,St};
- true -> check_liveness(R, Is, St)
+ {x,X} ->
+ case X < Live orelse member(R, Ss) of
+ true -> {used,St};
+ false -> {killed,St}
+ end;
+ {y,_} ->
+ case member(R, Ss) of
+ true -> {used,St};
+ false ->
+ if
+ R =:= Dst -> {killed,St};
+ true -> check_liveness(R, Is, St)
+ end
+ end
end;
-check_liveness(R, [{bs_put_string,_,_}|Is], St) ->
- check_liveness(R, Is, St);
check_liveness(R, [{deallocate,_}|Is], St) ->
case R of
{y,_} -> {killed,St};
@@ -339,29 +323,20 @@ check_liveness(R, [{deallocate,_}|Is], St) ->
end;
check_liveness(R, [return|_], St) ->
check_liveness_live_ret(R, 1, St);
-check_liveness(R, [{call_last,Live,_,_}|_], St) ->
- check_liveness_live_ret(R, Live, St);
-check_liveness(R, [{call_only,Live,_}|_], St) ->
- check_liveness_live_ret(R, Live, St);
-check_liveness(R, [{call_ext_last,Live,_,_}|_], St) ->
- check_liveness_live_ret(R, Live, St);
-check_liveness(R, [{call_ext_only,Live,_}|_], St) ->
- check_liveness_live_ret(R, Live, St);
check_liveness(R, [{call,Live,_}|Is], St) ->
case R of
{x,X} when X < Live -> {used,St};
{x,_} -> {killed,St};
{y,_} -> check_liveness(R, Is, St)
end;
-check_liveness(R, [{call_ext,Live,Func}|Is], St) ->
+check_liveness(R, [{call_ext,Live,_}=I|Is], St) ->
case R of
{x,X} when X < Live ->
{used,St};
{x,_} ->
{killed,St};
{y,_} ->
- {extfunc,Mod,Name,Arity} = Func,
- case erl_bifs:is_exit_bif(Mod, Name, Arity) of
+ case beam_jump:is_exit_instruction(I) of
false ->
check_liveness(R, Is, St);
true ->
@@ -387,14 +362,6 @@ check_liveness(R, [{apply,Args}|Is], St) ->
{x,_} -> {killed,St};
{y,_} -> check_liveness(R, Is, St)
end;
-check_liveness(R, [{apply_last,Args,_}|_], St) ->
- check_liveness_live_ret(R, Args+2, St);
-check_liveness(R, [send|Is], St) ->
- case R of
- {x,X} when X < 2 -> {used,St};
- {x,_} -> {killed,St};
- {y,_} -> check_liveness(R, Is, St)
- end;
check_liveness({x,R}, [{'%live',Live}|Is], St) ->
if
R < Live -> check_liveness(R, Is, St);
@@ -429,25 +396,9 @@ check_liveness(R, [{gc_bif,Op,{f,Fail},Live,Ss,D}|Is], St0) ->
Other
end
end;
-check_liveness(R, [{bs_add,{f,0},Ss,D}|Is], St) ->
+check_liveness(R, [{bs_put,{f,0},_,Ss}|Is], St) ->
case member(R, Ss) of
true -> {used,St};
- false when R =:= D -> {killed,St};
- false -> check_liveness(R, Is, St)
- end;
-check_liveness(R, [{bs_put_binary,{f,0},Sz,_,_,Src}|Is], St) ->
- case member(R, [Sz,Src]) of
- true -> {used,St};
- false -> check_liveness(R, Is, St)
- end;
-check_liveness(R, [{bs_put_integer,{f,0},Sz,_,_,Src}|Is], St) ->
- case member(R, [Sz,Src]) of
- true -> {used,St};
- false -> check_liveness(R, Is, St)
- end;
-check_liveness(R, [{bs_put_float,{f,0},Sz,_,_,Src}|Is], St) ->
- case member(R, [Sz,Src]) of
- true -> {used,St};
false -> check_liveness(R, Is, St)
end;
check_liveness(R, [{bs_restore2,S,_}|Is], St) ->
@@ -472,6 +423,16 @@ check_liveness(R, [{make_fun2,_,_,_,NumFree}|Is], St) ->
{x,_} -> {killed,St};
_ -> check_liveness(R, Is, St)
end;
+check_liveness({x,_}=R, [{'catch',_,_}|Is], St) ->
+ %% All x registers will be killed if an exception occurs.
+ %% Therefore we only need to check the liveness for the
+ %% instructions following the catch instruction.
+ check_liveness(R, Is, St);
+check_liveness({x,_}=R, [{'try',_,_}|Is], St) ->
+ %% All x registers will be killed if an exception occurs.
+ %% Therefore we only need to check the liveness for the
+ %% instructions inside the 'try' block.
+ check_liveness(R, Is, St);
check_liveness(R, [{try_end,Y}|Is], St) ->
case R of
Y ->
@@ -602,26 +563,50 @@ check_killed_block(_, []) -> transparent.
%%
%% (Unknown instructions will cause an exception.)
-check_used_block({x,X}=R, [{set,_,_,{alloc,Live,_}}|Is]) ->
+check_used_block_fun(D) ->
+ fun(R, Is) -> check_used_block(R, Is, D) end.
+
+check_used_block({x,X}=R, [{set,Ds,Ss,{alloc,Live,Op}}|Is], D) ->
if
X >= Live -> killed;
- true -> check_used_block(R, Is)
+ true ->
+ case member(R, Ss) orelse
+ is_reg_used_at(R, Op, D) of
+ true -> used;
+ false ->
+ case member(R, Ds) of
+ true -> killed;
+ false -> check_used_block(R, Is, D)
+ end
+ end
end;
-check_used_block(R, [{set,Ds,Ss,_Op}|Is]) ->
- case member(R, Ss) of
+check_used_block(R, [{set,Ds,Ss,Op}|Is], D) ->
+ case member(R, Ss) orelse
+ is_reg_used_at(R, Op, D) of
true -> used;
false ->
case member(R, Ds) of
true -> killed;
- false -> check_used_block(R, Is)
+ false -> check_used_block(R, Is, D)
end
end;
-check_used_block(R, [{'%live',Live}|Is]) ->
+check_used_block(R, [{'%live',Live}|Is], D) ->
case R of
{x,X} when X >= Live -> killed;
- _ -> check_used_block(R, Is)
+ _ -> check_used_block(R, Is, D)
end;
-check_used_block(_, []) -> transparent.
+check_used_block(_, [], _) -> transparent.
+
+is_reg_used_at(R, {gc_bif,_,{f,Lbl}}, D) ->
+ is_reg_used_at_1(R, Lbl, D);
+is_reg_used_at(R, {bif,_,{f,Lbl}}, D) ->
+ is_reg_used_at_1(R, Lbl, D);
+is_reg_used_at(_, _, _) -> false.
+
+is_reg_used_at_1(_, 0, _) ->
+ false;
+is_reg_used_at_1(R, Lbl, D) ->
+ not is_not_used_at(R, Lbl, D).
index_labels_1([{label,Lbl}|Is0], Acc) ->
Is = lists:dropwhile(fun({label,_}) -> true;
@@ -654,49 +639,21 @@ combine_alloc_lists_1([]) -> [].
live_opt([{bs_context_to_binary,Src}=I|Is], Regs0, D, Acc) ->
Regs = x_live([Src], Regs0),
live_opt(Is, Regs, D, [I|Acc]);
-live_opt([{bs_add,Fail,[Src1,Src2,_],Dst}=I|Is], Regs0, D, Acc) ->
- Regs1 = x_live([Src1,Src2], x_dead([Dst], Regs0)),
- Regs = live_join_label(Fail, D, Regs1),
- live_opt(Is, Regs, D, [I|Acc]);
-live_opt([{bs_init2,Fail,_,_,Live,_,_}=I|Is], _, D, Acc) ->
- Regs1 = live_call(Live),
+live_opt([{bs_init,Fail,_,none,Ss,Dst}=I|Is], Regs0, D, Acc) ->
+ Regs1 = x_live(Ss, x_dead([Dst], Regs0)),
Regs = live_join_label(Fail, D, Regs1),
live_opt(Is, Regs, D, [I|Acc]);
-live_opt([{bs_init_bits,Fail,Src1,_,Live,_,Src2}=I|Is], _, D, Acc) ->
- Regs1 = live_call(Live),
- Regs2 = x_live([Src1,Src2], Regs1),
- Regs = live_join_label(Fail, D, Regs2),
+live_opt([{bs_init,Fail,Info,Live0,Ss,Dst}|Is], Regs0, D, Acc) ->
+ Regs1 = x_dead([Dst], Regs0),
+ Live = live_regs(Regs1),
+ true = Live =< Live0, %Assertion.
+ Regs2 = live_call(Live),
+ Regs3 = x_live(Ss, Regs2),
+ Regs = live_join_label(Fail, D, Regs3),
+ I = {bs_init,Fail,Info,Live,Ss,Dst},
live_opt(Is, Regs, D, [I|Acc]);
-live_opt([{bs_append,Fail,Src1,_,Live,_,Src2,_,Dst}=I|Is], _Regs0, D, Acc) ->
- Regs1 = x_dead([Dst], x_live([Src1,Src2], live_call(Live))),
- Regs = live_join_label(Fail, D, Regs1),
- live_opt(Is, Regs, D, [I|Acc]);
-live_opt([{bs_private_append,Fail,Src1,_,Src2,_,Dst}=I|Is], Regs0, D, Acc) ->
- Regs1 = x_live([Src1,Src2], x_dead([Dst], Regs0)),
- Regs = live_join_label(Fail, D, Regs1),
- live_opt(Is, Regs, D, [I|Acc]);
-live_opt([{bs_put_binary,Fail,Src1,_,_,Src2}=I|Is], Regs0, D, Acc) ->
- Regs1 = x_live([Src1,Src2], Regs0),
- Regs = live_join_label(Fail, D, Regs1),
- live_opt(Is, Regs, D, [I|Acc]);
-live_opt([{bs_put_float,Fail,Src1,_,_,Src2}=I|Is], Regs0, D, Acc) ->
- Regs1 = x_live([Src1,Src2], Regs0),
- Regs = live_join_label(Fail, D, Regs1),
- live_opt(Is, Regs, D, [I|Acc]);
-live_opt([{bs_put_integer,Fail,Src1,_,_,Src2}=I|Is], Regs0, D, Acc) ->
- Regs1 = x_live([Src1,Src2], Regs0),
- Regs = live_join_label(Fail, D, Regs1),
- live_opt(Is, Regs, D, [I|Acc]);
-live_opt([{bs_put_utf8,Fail,_,Src}=I|Is], Regs0, D, Acc) ->
- Regs1 = x_live([Src], Regs0),
- Regs = live_join_label(Fail, D, Regs1),
- live_opt(Is, Regs, D, [I|Acc]);
-live_opt([{bs_put_utf16,Fail,_,Src}=I|Is], Regs0, D, Acc) ->
- Regs1 = x_live([Src], Regs0),
- Regs = live_join_label(Fail, D, Regs1),
- live_opt(Is, Regs, D, [I|Acc]);
-live_opt([{bs_put_utf32,Fail,_,Src}=I|Is], Regs0, D, Acc) ->
- Regs1 = x_live([Src], Regs0),
+live_opt([{bs_put,Fail,_,Ss}=I|Is], Regs0, D, Acc) ->
+ Regs1 = x_live(Ss, Regs0),
Regs = live_join_label(Fail, D, Regs1),
live_opt(Is, Regs, D, [I|Acc]);
live_opt([{bs_restore2,Src,_}=I|Is], Regs0, D, Acc) ->
@@ -705,14 +662,6 @@ live_opt([{bs_restore2,Src,_}=I|Is], Regs0, D, Acc) ->
live_opt([{bs_save2,Src,_}=I|Is], Regs0, D, Acc) ->
Regs = x_live([Src], Regs0),
live_opt(Is, Regs, D, [I|Acc]);
-live_opt([{bs_utf8_size,Fail,Src,Dst}=I|Is], Regs0, D, Acc) ->
- Regs1 = x_live([Src], x_dead([Dst], Regs0)),
- Regs = live_join_label(Fail, D, Regs1),
- live_opt(Is, Regs, D, [I|Acc]);
-live_opt([{bs_utf16_size,Fail,Src,Dst}=I|Is], Regs0, D, Acc) ->
- Regs1 = x_live([Src], x_dead([Dst], Regs0)),
- Regs = live_join_label(Fail, D, Regs1),
- live_opt(Is, Regs, D, [I|Acc]);
live_opt([{test,bs_start_match2,Fail,Live,[Src,_],_}=I|Is], _, D, Acc) ->
Regs0 = live_call(Live),
Regs1 = x_live([Src], Regs0),
@@ -741,33 +690,22 @@ live_opt([{badmatch,Src}=I|Is], _, D, Acc) ->
live_opt([{case_end,Src}=I|Is], _, D, Acc) ->
Regs = x_live([Src], 0),
live_opt(Is, Regs, D, [I|Acc]);
+live_opt([{try_case_end,Src}=I|Is], _, D, Acc) ->
+ Regs = x_live([Src], 0),
+ live_opt(Is, Regs, D, [I|Acc]);
live_opt([if_end=I|Is], _, D, Acc) ->
Regs = 0,
live_opt(Is, Regs, D, [I|Acc]);
-live_opt([bs_init_writable=I|Is], _, D, Acc) ->
- live_opt(Is, live_call(1), D, [I|Acc]);
live_opt([{call,Arity,_}=I|Is], _, D, Acc) ->
live_opt(Is, live_call(Arity), D, [I|Acc]);
live_opt([{call_ext,Arity,_}=I|Is], _, D, Acc) ->
live_opt(Is, live_call(Arity), D, [I|Acc]);
live_opt([{call_fun,Arity}=I|Is], _, D, Acc) ->
live_opt(Is, live_call(Arity+1), D, [I|Acc]);
-live_opt([{call_last,Arity,_,_}=I|Is], _, D, Acc) ->
- live_opt(Is, live_call(Arity), D, [I|Acc]);
-live_opt([{call_ext_last,Arity,_,_}=I|Is], _, D, Acc) ->
- live_opt(Is, live_call(Arity), D, [I|Acc]);
live_opt([{apply,Arity}=I|Is], _, D, Acc) ->
live_opt(Is, live_call(Arity+2), D, [I|Acc]);
-live_opt([{apply_last,Arity,_}=I|Is], _, D, Acc) ->
- live_opt(Is, live_call(Arity+2), D, [I|Acc]);
-live_opt([{call_only,Arity,_}=I|Is], _, D, Acc) ->
- live_opt(Is, live_call(Arity), D, [I|Acc]);
-live_opt([{call_ext_only,Arity,_}=I|Is], _, D, Acc) ->
- live_opt(Is, live_call(Arity), D, [I|Acc]);
live_opt([{make_fun2,_,_,_,Arity}=I|Is], _, D, Acc) ->
live_opt(Is, live_call(Arity), D, [I|Acc]);
-live_opt([send=I|Is], _, D, Acc) ->
- live_opt(Is, live_call(2), D, [I|Acc]);
live_opt([{test,_,Fail,Ss}=I|Is], Regs0, D, Acc) ->
Regs1 = x_live(Ss, Regs0),
Regs = live_join_label(Fail, D, Regs1),
@@ -777,16 +715,14 @@ live_opt([{test,_,Fail,Live,Ss,_}=I|Is], _, D, Acc) ->
Regs1 = x_live(Ss, Regs0),
Regs = live_join_label(Fail, D, Regs1),
live_opt(Is, Regs, D, [I|Acc]);
-live_opt([{select_val,Src,Fail,{list,List}}=I|Is], Regs0, D, Acc) ->
+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([{select_tuple_arity,Src,Fail,{list,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',_,Fail}=I|Is], Regs0, D, Acc) ->
- Regs = live_join_label(Fail, D, Regs0),
+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]);
@@ -796,14 +732,10 @@ live_opt([timeout=I|Is], _, D, Acc) ->
live_opt(Is, 0, D, [I|Acc]);
%% Transparent instructions - they neither use nor modify x registers.
-live_opt([{bs_put_string,_,_}=I|Is], Regs, D, Acc) ->
- live_opt(Is, Regs, D, [I|Acc]);
live_opt([{deallocate,_}=I|Is], Regs, D, Acc) ->
live_opt(Is, Regs, D, [I|Acc]);
live_opt([{kill,_}=I|Is], Regs, D, Acc) ->
live_opt(Is, Regs, D, [I|Acc]);
-live_opt([{try_case_end,_}=I|Is], Regs, D, Acc) ->
- live_opt(Is, Regs, D, [I|Acc]);
live_opt([{try_end,_}=I|Is], Regs, D, Acc) ->
live_opt(Is, Regs, D, [I|Acc]);
live_opt([{loop_rec_end,_}=I|Is], Regs, D, Acc) ->
@@ -826,13 +758,24 @@ live_opt([{allocate_heap,_,_,Live}=I|Is], _, D, Acc) ->
live_opt([], _, _, Acc) -> Acc.
-live_opt_block([{set,[],[],{alloc,Live,_}}=I|Is], _, D, Acc) ->
- live_opt_block(Is, live_call(Live), D, [I|Acc]);
-live_opt_block([{set,Ds,Ss,Op}=I|Is], Regs0, D, Acc) ->
- Regs = case Op of
- {alloc,Live,_} -> live_call(Live);
- _ -> x_live(Ss, x_dead(Ds, Regs0))
- end,
+live_opt_block([{set,Ds,Ss,Op}=I0|Is], Regs0, D, Acc) ->
+ Regs1 = x_live(Ss, x_dead(Ds, Regs0)),
+ {I,Regs} = case Op of
+ {alloc,Live0,Alloc} ->
+ %% The life-time analysis used by the code generator
+ %% is sometimes too conservative, so it may be
+ %% possible to lower the number of live registers
+ %% based on the exact liveness information.
+ %% The main benefit is that more optimizations that
+ %% depend on liveness information (such as the
+ %% beam_bool and beam_dead passes) may be applied.
+ Live = live_regs(Regs1),
+ true = Live =< Live0, %Assertion.
+ I1 = {set,Ds,Ss,{alloc,Live,Alloc}},
+ {I1,live_call(Live)};
+ _ ->
+ {I0,Regs1}
+ end,
case Ds of
[{x,X}] ->
case (not is_live(X, Regs0)) andalso Op =:= move of
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-29 13:28:03 +0000