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Diffstat (limited to 'lib/compiler/src/beam_reorder.erl')
| -rw-r--r-- | lib/compiler/src/beam_reorder.erl | 150 |
1 files changed, 0 insertions, 150 deletions
diff --git a/lib/compiler/src/beam_reorder.erl b/lib/compiler/src/beam_reorder.erl deleted file mode 100644 index 8d2ef5a431..0000000000 --- a/lib/compiler/src/beam_reorder.erl +++ /dev/null @@ -1,150 +0,0 @@ -%% -%% %CopyrightBegin% -%% -%% Copyright Ericsson AB 1999-2018. 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]). - --spec module(beam_utils:module_code(), [compile:option()]) -> - {'ok',beam_utils:module_code()}. - -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 -> - 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([{Op,_,_}=TryCatch|[I|Is]=Is0], D, Acc) - when Op =:= 'catch'; Op =:= 'try' -> - %% Don't allow 'try' or 'catch' instructions to split blocks if - %% it can be avoided. - case is_safe(I) of - false -> - reorder_1(Is0, D, [TryCatch|Acc]); - true -> - reorder_1([TryCatch|Is], D, [I|Acc]) - end; -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,_},[Src|_]}=I|Is], D, - [{get_tuple_element,Src,_,_}|_]=Acc) -> - %% We want to avoid code that can confuse beam_validator such as: - %% is_tuple Fail Src - %% test_arity Fail Src Arity - %% is_map Fail Src - %% get_tuple_element Src Pos Dst - %% Therefore, don't reorder the instructions in such cases. - reorder_1(Is, D, [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}=I0|Is], D, - [{get_tuple_element,{x,Tup},_,{x,Dst}}=G|Acc]=Acc0) -> - case Tup < Dst andalso Dst+1 =:= Live of - true -> - %% Move allocation instruction upwards past - %% get_tuple_element instructions to create more - %% opportunities for moving get_tuple_element - %% instructions. - I = {allocate_zero,N,Dst}, - reorder_1([I,G|Is], D, Acc); - false -> - reorder_1(Is, D, [I0|Acc0]) - end; -reorder_1([I|Is], D, Acc) -> - reorder_1(Is, D, [I|Acc]); -reorder_1([], _, Acc) -> reverse(Acc). - -%% is_safe(Instruction) -> true|false -%% Test whether an instruction is safe (cannot cause an exception). - -is_safe({kill,_}) -> true; -is_safe({move,_,_}) -> true; -is_safe({put,_}) -> true; -is_safe({put_list,_,_,_}) -> true; -is_safe({put_tuple,_,_}) -> true; -is_safe({test_heap,_,_}) -> true; -is_safe(_) -> false. |