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-rw-r--r--lib/compiler/src/Makefile1
-rw-r--r--lib/compiler/src/beam_reorder.erl113
-rw-r--r--lib/compiler/src/beam_utils.erl9
-rw-r--r--lib/compiler/src/compile.erl4
-rw-r--r--lib/compiler/src/compiler.app.src1
-rw-r--r--lib/compiler/test/misc_SUITE.erl8
6 files changed, 135 insertions, 1 deletions
diff --git a/lib/compiler/src/Makefile b/lib/compiler/src/Makefile
index 299b2892fc..ae4007c61c 100644
--- a/lib/compiler/src/Makefile
+++ b/lib/compiler/src/Makefile
@@ -62,6 +62,7 @@ MODULES = \
beam_opcodes \
beam_peep \
beam_receive \
+ beam_reorder \
beam_split \
beam_trim \
beam_type \
diff --git a/lib/compiler/src/beam_reorder.erl b/lib/compiler/src/beam_reorder.erl
new file mode 100644
index 0000000000..3230e33dbd
--- /dev/null
+++ b/lib/compiler/src/beam_reorder.erl
@@ -0,0 +1,113 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 1999-2013. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%% http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+-module(beam_reorder).
+
+-export([module/2]).
+-import(lists, [member/2,reverse/1]).
+
+module({Mod,Exp,Attr,Fs0,Lc}, _Opt) ->
+ Fs = [function(F) || F <- Fs0],
+ {ok,{Mod,Exp,Attr,Fs,Lc}}.
+
+function({function,Name,Arity,CLabel,Is0}) ->
+ try
+ Is = reorder(Is0),
+ {function,Name,Arity,CLabel,Is}
+ catch
+ Class:Error ->
+ Stack = erlang:get_stacktrace(),
+ io:fwrite("Function: ~w/~w\n", [Name,Arity]),
+ erlang:raise(Class, Error, Stack)
+ end.
+
+%% reorder(Instructions0) -> Instructions
+%% Reorder instructions before the beam_block pass, because reordering
+%% will be more cumbersome when the blocks are in place.
+%%
+%% Execution of get_tuple_element instructions can be delayed until
+%% they are actually needed. Consider the sequence:
+%%
+%% get_tuple_element Tuple Pos Dst
+%% test Test Fail Operands
+%%
+%% If Dst is killed at label Fail (and not referenced in Operands),
+%% we can can swap the instructions:
+%%
+%% test Test Fail Operands
+%% get_tuple_element Tuple Pos Dst
+%%
+%% That can be beneficial in two ways: Firstly, if the branch is taken
+%% we have avoided execution of the get_tuple_element instruction.
+%% Secondly, even if the branch is not taken, subsequent optimization
+%% (opt_blocks/1) may be able to change Dst to the final destination
+%% register and eliminate a 'move' instruction.
+
+reorder(Is) ->
+ D = beam_utils:index_labels(Is),
+ reorder_1(Is, D, []).
+
+reorder_1([{label,L}=I|_], D, Acc) ->
+ Is = beam_utils:code_at(L, D),
+ reorder_1(Is, D, [I|Acc]);
+reorder_1([{test,is_nonempty_list,_,_}=I|Is], D, Acc) ->
+ %% The run-time system may combine the is_nonempty_list test with
+ %% the following get_list instruction.
+ reorder_1(Is, D, [I|Acc]);
+reorder_1([{test,_,_,_}=I,
+ {select,_,_,_,_}=S|Is], D, Acc) ->
+ %% There is nothing to gain by inserting a get_tuple_element
+ %% instruction between the test instruction and the select
+ %% instruction.
+ reorder_1(Is, D, [S,I|Acc]);
+reorder_1([{test,_,{f,L},Ss}=I|Is0], D0,
+ [{get_tuple_element,_,_,El}=G|Acc0]=Acc) ->
+ case member(El, Ss) of
+ true ->
+ reorder_1(Is0, D0, [I|Acc]);
+ false ->
+ case beam_utils:is_killed_at(El, L, D0) of
+ true ->
+ Is = [I,G|Is0],
+ reorder_1(Is, D0, Acc0);
+ false ->
+ case beam_utils:is_killed(El, Is0, D0) of
+ true ->
+ Code0 = beam_utils:code_at(L, D0),
+ Code = [G|Code0],
+ D = beam_utils:index_label(L, Code, D0),
+ Is = [I|Is0],
+ reorder_1(Is, D, Acc0);
+ false ->
+ reorder_1(Is0, D0, [I|Acc])
+ end
+ end
+ end;
+reorder_1([{allocate_zero,N,Live}|Is], D,
+ [{get_tuple_element,_,_,{x,X}}=G|Acc])
+ when X+1 =:= Live ->
+ %% Move allocation instruction upwards past get_tuple_element
+ %% instructions to give more opportunities for moving
+ %% get_tuple_element instructions.
+ I = {allocate_zero,N,X},
+ reorder_1([I,G|Is], D, Acc);
+reorder_1([I|Is], D, Acc) ->
+ reorder_1(Is, D, [I|Acc]);
+reorder_1([], _, Acc) -> reverse(Acc).
diff --git a/lib/compiler/src/beam_utils.erl b/lib/compiler/src/beam_utils.erl
index fbcd5de1bb..68d6105cfa 100644
--- a/lib/compiler/src/beam_utils.erl
+++ b/lib/compiler/src/beam_utils.erl
@@ -484,6 +484,15 @@ check_liveness(R, [{get_map_elements,{f,Fail},S,{list,L}}|Is], St0) ->
Other
end
end;
+check_liveness(R, [{test_heap,N,Live}|Is], St) ->
+ I = {block,[{set,[],[],{alloc,Live,{nozero,nostack,N,[]}}}]},
+ check_liveness(R, [I|Is], St);
+check_liveness(R, [{allocate_zero,N,Live}|Is], St) ->
+ I = {block,[{set,[],[],{alloc,Live,{zero,N,0,[]}}}]},
+ check_liveness(R, [I|Is], St);
+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|_] ->
diff --git a/lib/compiler/src/compile.erl b/lib/compiler/src/compile.erl
index cf79fdc9f9..605f5b8fd5 100644
--- a/lib/compiler/src/compile.erl
+++ b/lib/compiler/src/compile.erl
@@ -673,7 +673,9 @@ asm_passes() ->
[{pass,beam_a},
{iff,da,{listing,"a"}},
{unless,no_postopt,
- [{pass,beam_block},
+ [{unless,no_reorder,{pass,beam_reorder}},
+ {iff,dre,{listing,"reorder"}},
+ {pass,beam_block},
{iff,dblk,{listing,"block"}},
{unless,no_except,{pass,beam_except}},
{iff,dexcept,{listing,"except"}},
diff --git a/lib/compiler/src/compiler.app.src b/lib/compiler/src/compiler.app.src
index afb85f4710..62ea9cee80 100644
--- a/lib/compiler/src/compiler.app.src
+++ b/lib/compiler/src/compiler.app.src
@@ -37,6 +37,7 @@
beam_opcodes,
beam_peep,
beam_receive,
+ beam_reorder,
beam_split,
beam_trim,
beam_type,
diff --git a/lib/compiler/test/misc_SUITE.erl b/lib/compiler/test/misc_SUITE.erl
index 8606935504..3582e055c8 100644
--- a/lib/compiler/test/misc_SUITE.erl
+++ b/lib/compiler/test/misc_SUITE.erl
@@ -192,6 +192,14 @@ silly_coverage(Config) when is_list(Config) ->
{label,2}|non_proper_list]}],99},
expect_error(fun() -> beam_a:module(BeamAInput, []) end),
+ %% beam_reorder
+ BlockInput = {?MODULE,[{foo,0}],[],
+ [{function,foo,0,2,
+ [{label,1},
+ {func_info,{atom,?MODULE},{atom,foo},0},
+ {label,2}|non_proper_list]}],99},
+ expect_error(fun() -> beam_reorder:module(BlockInput, []) end),
+
%% beam_block
BlockInput = {?MODULE,[{foo,0}],[],
[{function,foo,0,2,
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-13 12:21:20 +0000