File 1577-Remove-the-beam_peep-pass.patch of Package erlang

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File 1577-Remove-the-beam_peep-pass.patch of Package erlang (Revision 8ae270ec351a9967251049ec5fe5606a)

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From 8e4c66243cbb724c10c975a4ba9fd7b0bd81fc5d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Fri, 20 Aug 2021 07:19:57 +0200
Subject: [PATCH 7/7] Remove the beam_peep pass

All optimizations in `beam_peep` have either been reimplemented as
optimizations on SSA code or moved to other passes.
---
 lib/compiler/src/Makefile           |   1 -
 lib/compiler/src/beam_clean.erl     |   4 -
 lib/compiler/src/beam_peep.erl      | 223 ----------------------------
 lib/compiler/src/compile.erl        |   3 -
 lib/compiler/src/compiler.app.src   |   1 -
 lib/compiler/test/compile_SUITE.erl |   1 -
 lib/compiler/test/misc_SUITE.erl    |  11 --
 7 files changed, 244 deletions(-)
 delete mode 100644 lib/compiler/src/beam_peep.erl

diff --git a/lib/compiler/src/Makefile b/lib/compiler/src/Makefile
index f195e16dc6..24414fef77 100644
--- a/lib/compiler/src/Makefile
+++ b/lib/compiler/src/Makefile
@@ -58,7 +58,6 @@ MODULES =  \
 	beam_jump \
 	beam_listing \
 	beam_opcodes \
-	beam_peep \
 	beam_ssa \
 	beam_ssa_bc_size \
 	beam_ssa_bool \
diff --git a/lib/compiler/src/beam_clean.erl b/lib/compiler/src/beam_clean.erl
index 643cc1c386..e771818d10 100644
--- a/lib/compiler/src/beam_clean.erl
+++ b/lib/compiler/src/beam_clean.erl
@@ -22,7 +22,6 @@
 -module(beam_clean).
 
 -export([module/2]).
--export([clean_labels/1]).
 
 -spec module(beam_utils:module_code(), [compile:option()]) ->
                     {'ok',beam_utils:module_code()}.
@@ -98,9 +97,6 @@ add_to_work_list(F, {Fs,Used}=Sets) ->
 	     lc :: non_neg_integer()      %Label counter
 	     }).
 
--spec clean_labels([beam_utils:instruction()]) ->
-                          {[beam_utils:instruction()],pos_integer()}.
-
 clean_labels(Fs0) ->
     St0 = #st{lmap=[],entry=1,lc=1},
     {Fs1,#st{lmap=Lmap0,lc=Lc}} = function_renumber(Fs0, St0, []),
diff --git a/lib/compiler/src/beam_peep.erl b/lib/compiler/src/beam_peep.erl
deleted file mode 100644
index da59aea2bd..0000000000
--- a/lib/compiler/src/beam_peep.erl
+++ /dev/null
@@ -1,223 +0,0 @@
-%%
-%% %CopyrightBegin%
-%%
-%% Copyright Ericsson AB 2008-2020. 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_peep).
-
--export([module/2]).
-
--import(lists, [reverse/1,member/2,usort/1]).
-
--spec module(beam_utils:module_code(), [compile:option()]) ->
-                    {'ok',beam_utils:module_code()}.
-
-module({Mod,Exp,Attr,Fs0,_}, _Opts) ->
-    %% First coalesce adjacent labels.
-    {Fs1,Lc} = beam_clean:clean_labels(Fs0),
-
-    %% Do the peep hole optimizations.
-    Fs = [function(F) || F <- Fs1],
-    {ok,{Mod,Exp,Attr,Fs,Lc}}.
-
-function({function,Name,Arity,CLabel,Is0}) ->
-    try
-	Is1 = peep(Is0),
-	Is = beam_jump:remove_unused_labels(Is1),
-	{function,Name,Arity,CLabel,Is}
-    catch
-        Class:Error:Stack ->
-	    io:fwrite("Function: ~w/~w\n", [Name,Arity]),
-	    erlang:raise(Class, Error, Stack)
-    end.
-
-
-%% Peep-hole optimizations suitable to perform when most of the
-%% optimations passes have been run.
-%%
-%% (1) In a sequence of tests, we can remove any test instruction
-%%     that has been previously seen, because it will certainly
-%%     succeed.
-%%
-%%     For instance, in the following code sequence
-%%
-%%       is_eq_exact _Fail SomeRegister SomeLiteral
-%%       is_ne_exact _Fail SomeOtherRegister SomeOtherLiteral
-%%       is_eq_exact _Fail SomeRegister SomeLiteral
-%%       is_ne_exact _Fail SomeOtherRegister StillSomeOtherLiteral
-%%
-%%     the third test is redundant. The code sequence will be produced
-%%     by a combination of semicolon and command guards, such as
-%%  
-%%      InEncoding =:= latin1, OutEncoding =:= unicode; 
-%%      InEncoding =:= latin1, OutEncoding =:= utf8 ->
-%%
-
-peep(Is) ->
-    peep(Is, gb_sets:empty(), []).
-
-peep([{bif,tuple_size,_,[_]=Ops,Dst}=I|Is], SeenTests0, Acc) ->
-    %% Pretend that we have seen {test,is_tuple,_,Ops}.
-    SeenTests1 = gb_sets:add({is_tuple,Ops}, SeenTests0),
-    %% Kill all remembered tests that depend on the destination register.
-    SeenTests = kill_seen(Dst, SeenTests1),
-    peep(Is, SeenTests, [I|Acc]);
-peep([{bif,map_get,_,[Key,Map],Dst}=I|Is], SeenTests0, Acc) ->
-    %% Pretend that we have seen {test,has_map_fields,_,[Map,Key]}
-    SeenTests1 = gb_sets:add({has_map_fields,[Map,Key]}, SeenTests0),
-    %% Kill all remembered tests that depend on the destination register.
-    SeenTests = kill_seen(Dst, SeenTests1),
-    peep(Is, SeenTests, [I|Acc]);
-peep([{bif,_,_,_,Dst}=I|Is], SeenTests0, Acc) ->
-    %% Kill all remembered tests that depend on the destination register.
-    SeenTests = kill_seen(Dst, SeenTests0),
-    peep(Is, SeenTests, [I|Acc]);
-peep([{gc_bif,_,_,_,_,Dst}=I|Is], SeenTests0, Acc) ->
-    %% Kill all remembered tests that depend on the destination register.
-    SeenTests = kill_seen(Dst, SeenTests0),
-    peep(Is, SeenTests, [I|Acc]);
-peep([{jump,{f,L}},{label,L}=I|Is], _, Acc) ->
-    %% Sometimes beam_jump has missed this optimization.
-    peep(Is, gb_sets:empty(), [I|Acc]);
-peep([{select,select_val,R,F,Vls0}|Is], SeenTests0, Acc0) ->
-    case prune_redundant_values(Vls0, F) of
-	[] ->
-	    %% No values left. Must convert to plain jump.
-	    I = {jump,F},
-	    peep([I|Is], gb_sets:empty(), Acc0);
-        [{atom,_}=Value,Lbl] ->
-            %% Single value left. Convert to regular test.
-            Is1 = [{test,is_eq_exact,F,[R,Value]},{jump,Lbl}|Is],
-            peep(Is1, SeenTests0, Acc0);
-        [{integer,_}=Value,Lbl] ->
-            %% Single value left. Convert to regular test.
-            Is1 = [{test,is_eq_exact,F,[R,Value]},{jump,Lbl}|Is],
-            peep(Is1, SeenTests0, Acc0);
-	[{atom,B1},Lbl,{atom,B2},Lbl] when B1 =:= not B2 ->
-            %% Replace with is_boolean test.
-            Is1 = [{test,is_boolean,F,[R]},{jump,Lbl}|Is],
-            peep(Is1, SeenTests0, Acc0);
-	[_|_]=Vls ->
-	    I = {select,select_val,R,F,Vls},
-	    peep(Is, gb_sets:empty(), [I|Acc0])
-    end;
-peep([{get_map_elements,Fail,Src,List}=I|Is], _SeenTests, Acc0) ->
-    SeenTests = gb_sets:empty(),
-    case simplify_get_map_elements(Fail, Src, List, Acc0) of
-        {ok,Acc} ->
-            peep(Is, SeenTests, Acc);
-        error ->
-            peep(Is, SeenTests, [I|Acc0])
-    end;
-peep([{test,has_map_fields,Fail,Ops}=I|Is], SeenTests, Acc0) ->
-    case simplify_has_map_fields(Fail, Ops, Acc0) of
-        {ok,Acc} ->
-            peep(Is, SeenTests, Acc);
-        error ->
-            peep(Is, SeenTests, [I|Acc0])
-    end;
-peep([{test,Op,_,Ops}=I|Is], SeenTests0, Acc) ->
-    case beam_utils:is_pure_test(I) of
-	false ->
-	    %% Bit syntax matching, which may modify registers and/or
-	    %% match state. Clear all information about tests that
-	    %% has succeeded.
-	    peep(Is, gb_sets:empty(), [I|Acc]);
-	true ->
-	    case is_test_redundant(Op, Ops, SeenTests0) of
-		true ->
-		    %% This test or a similar test has already succeeded and
-		    %% is therefore redundant.
-		    peep(Is, SeenTests0, Acc);
-		false ->
-		    %% Remember that we have seen this test.
-		    Test = {Op,Ops},
-		    SeenTests = gb_sets:insert(Test, SeenTests0),
-		    peep(Is, SeenTests, [I|Acc])
-	    end
-    end;
-peep([I|Is], _, Acc) ->
-    %% An unknown instruction. Throw away all information we
-    %% have collected about test instructions.
-    peep(Is, gb_sets:empty(), [I|Acc]);
-peep([], _, Acc) -> reverse(Acc).
-
-is_test_redundant(Op, Ops, Seen) ->
-    gb_sets:is_element({Op,Ops}, Seen) orelse
-	is_test_redundant_1(Op, Ops, Seen).
-
-is_test_redundant_1(is_boolean, [R], Seen) ->
-    gb_sets:is_element({is_eq_exact,[R,{atom,false}]}, Seen) orelse
-	gb_sets:is_element({is_eq_exact,[R,{atom,true}]}, Seen);
-is_test_redundant_1(_, _, _) -> false.
-
-kill_seen(Dst, Seen0) ->
-    gb_sets:from_ordset(kill_seen_1(gb_sets:to_list(Seen0), Dst)).
-
-kill_seen_1([{_,Ops}=Test|T], Dst) ->
-    case member(Dst, Ops) of
-	true -> kill_seen_1(T, Dst);
-	false -> [Test|kill_seen_1(T, Dst)]
-    end;
-kill_seen_1([], _) -> [].
-
-prune_redundant_values([_Val,F|Vls], F) ->
-    prune_redundant_values(Vls, F);
-prune_redundant_values([Val,Lbl|Vls], F) ->
-    [Val,Lbl|prune_redundant_values(Vls, F)];
-prune_redundant_values([], _) -> [].
-
-simplify_get_map_elements(Fail, Src, {list,[Key,Dst]},
-                          [{get_map_elements,Fail,Src,{list,List1}}|Acc]) ->
-    case are_keys_literals([Key]) andalso are_keys_literals(List1) andalso
-        not is_source_overwritten(Src, List1) of
-        true ->
-            case member(Key, List1) of
-                true ->
-                    %% The key is already in the other list. That is
-                    %% very unusual, because there are optimizations to get
-                    %% rid of duplicate keys. Therefore, don't try to
-                    %% do anything smart here; just keep the
-                    %% get_map_elements instructions separate.
-                    error;
-                false ->
-                    List = [Key,Dst|List1],
-                    {ok,[{get_map_elements,Fail,Src,{list,List}}|Acc]}
-            end;
-        false ->
-            error
-    end;
-simplify_get_map_elements(_, _, _, _) -> error.
-
-simplify_has_map_fields(Fail, [Src|Keys0],
-                        [{test,has_map_fields,Fail,[Src|Keys1]}|Acc]) ->
-    case are_keys_literals(Keys0) andalso are_keys_literals(Keys1) of
-        true ->
-            Keys = usort(Keys0 ++ Keys1),
-            {ok,[{test,has_map_fields,Fail,[Src|Keys]}|Acc]};
-        false ->
-            error
-    end;
-simplify_has_map_fields(_, _, _) -> error.
-
-are_keys_literals([{x,_}|_]) -> false;
-are_keys_literals([{y,_}|_]) -> false;
-are_keys_literals([_|_]) -> true.
-
-is_source_overwritten(Src, [_Key,Src]) -> true;
-is_source_overwritten(_, _) -> false.
diff --git a/lib/compiler/src/compile.erl b/lib/compiler/src/compile.erl
index 7a36c6333a..ef421c20e7 100644
--- a/lib/compiler/src/compile.erl
+++ b/lib/compiler/src/compile.erl
@@ -916,8 +916,6 @@ asm_passes() ->
 	 {iff,dblk,{listing,"block"}},
 	 {unless,no_jopt,{pass,beam_jump}},
 	 {iff,djmp,{listing,"jump"}},
-	 {unless,no_peep_opt,{pass,beam_peep}},
-	 {iff,dpeep,{listing,"peep"}},
 	 {pass,beam_clean},
 	 {iff,dclean,{listing,"clean"}},
 	 {unless,no_stack_trimming,{pass,beam_trim}},
@@ -2020,7 +2018,6 @@ pre_load() ->
 	 beam_jump,
 	 beam_kernel_to_ssa,
 	 beam_opcodes,
-	 beam_peep,
 	 beam_ssa,
 	 beam_ssa_bc_size,
 	 beam_ssa_bool,
diff --git a/lib/compiler/src/compiler.app.src b/lib/compiler/src/compiler.app.src
index 08827c66b3..6aa4009645 100644
--- a/lib/compiler/src/compiler.app.src
+++ b/lib/compiler/src/compiler.app.src
@@ -34,7 +34,6 @@
              beam_kernel_to_ssa,
 	     beam_listing,
 	     beam_opcodes,
-	     beam_peep,
              beam_ssa,
              beam_ssa_bc_size,
              beam_ssa_bool,
diff --git a/lib/compiler/test/compile_SUITE.erl b/lib/compiler/test/compile_SUITE.erl
index 7ab621fab5..d9f1ba0a9d 100644
--- a/lib/compiler/test/compile_SUITE.erl
+++ b/lib/compiler/test/compile_SUITE.erl
@@ -486,7 +486,6 @@ do_file_listings(DataDir, PrivDir, [File|Files]) ->
             {dblk, ".block"},
             {djmp, ".jump"},
             {dclean, ".clean"},
-            {dpeep, ".peep"},
             {dopt, ".optimize"},
             {diffable, ".S"}],
     p_listings(List, Simple, TargetDir),
diff --git a/lib/compiler/test/misc_SUITE.erl b/lib/compiler/test/misc_SUITE.erl
index 5f24fb1f27..ae5fff2ed3 100644
--- a/lib/compiler/test/misc_SUITE.erl
+++ b/lib/compiler/test/misc_SUITE.erl
@@ -257,17 +257,6 @@ silly_coverage(Config) when is_list(Config) ->
     TrimInput = BlockInput,
     expect_error(fun() -> beam_trim:module(TrimInput, []) end),
 
-    %% beam_peep. This is tricky. Use a select instruction with
-    %% an odd number of elements in the list to crash
-    %% prune_redundant_values/2 but not beam_clean:clean_labels/1.
-    PeepInput = {?MODULE,[{foo,0}],[],
-		 [{function,foo,0,2,
-		   [{label,1},
-		    {func_info,{atom,?MODULE},{atom,foo},0},
-		    {label,2},{select,select_val,r,{f,2},[{f,2}]}]}],
-		 2},
-    expect_error(fun() -> beam_peep:module(PeepInput, []) end),
-
     BeamZInput = {?MODULE,[{foo,0}],[],
 		  [{function,foo,0,2,
 		    [{label,1},
-- 
2.31.1

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File 1577-Remove-the-beam_peep-pass.patch of Package erlang (Revision 8ae270ec351a9967251049ec5fe5606a)

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