%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2012-2018. 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%
%%
%% Purpose: Run directly after code generation to do any normalization
%% or preparation to simplify the optimization passes.
%% (Mandatory.)
-module(beam_a).
-export([module/2]).
-spec module(beam_asm: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
%% Rename certain operations to simplify the optimization passes.
Is1 = rename_instrs(Is0),
%% Remove unusued labels for cleanliness and to help
%% optimization passes and HiPE.
Is2 = beam_jump:remove_unused_labels(Is1),
%% Some optimization passes can't handle consecutive labels.
%% Coalesce multiple consecutive labels.
Is = coalesce_consecutive_labels(Is2, [], []),
{function,Name,Arity,CLabel,Is}
catch
Class:Error:Stack ->
io:fwrite("Function: ~w/~w\n", [Name,Arity]),
erlang:raise(Class, Error, Stack)
end.
rename_instrs([{test,is_eq_exact,_,[Dst,Src]}=Test,
{move,Src,Dst}|Is]) ->
%% The move instruction is not needed.
rename_instrs([Test|Is]);
rename_instrs([{test,is_eq_exact,_,[Same,Same]}|Is]) ->
%% Same literal or same register. Will always succeed.
rename_instrs(Is);
rename_instrs([{loop_rec,{f,Fail},{x,0}},{loop_rec_end,_},{label,Fail}|Is]) ->
%% This instruction sequence does nothing.
rename_instrs(Is);
rename_instrs([{apply_last,A,N}|Is]) ->
[{apply,A},{deallocate,N},return|rename_instrs(Is)];
rename_instrs([{call_last,A,F,N}|Is]) ->
[{call,A,F},{deallocate,N},return|rename_instrs(Is)];
rename_instrs([{call_ext_last,A,F,N}|Is]) ->
[{call_ext,A,F},{deallocate,N},return|rename_instrs(Is)];
rename_instrs([{call_only,A,F}|Is]) ->
[{call,A,F},return|rename_instrs(Is)];
rename_instrs([{call_ext_only,A,F}|Is]) ->
[{call_ext,A,F},return|rename_instrs(Is)];
rename_instrs([{'%live',_}|Is]) ->
%% Ignore old type of live annotation. Only happens when compiling
%% from very old .S files.
rename_instrs(Is);
rename_instrs([{get_list,S,D1,D2}|Is]) ->
%% Only happens when compiling from old .S files.
if
D1 =:= S ->
[{get_tl,S,D2},{get_hd,S,D1}|rename_instrs(Is)];
true ->
[{get_hd,S,D1},{get_tl,S,D2}|rename_instrs(Is)]
end;
rename_instrs([I|Is]) ->
[rename_instr(I)|rename_instrs(Is)];
rename_instrs([]) -> [].
rename_instr({bs_put_binary=I,F,Sz,U,Fl,Src}) ->
{bs_put,F,{I,U,Fl},[Sz,Src]};
rename_instr({bs_put_float=I,F,Sz,U,Fl,Src}) ->
{bs_put,F,{I,U,Fl},[Sz,Src]};
rename_instr({bs_put_integer=I,F,Sz,U,Fl,Src}) ->
{bs_put,F,{I,U,Fl},[Sz,Src]};
rename_instr({bs_put_utf8=I,F,Fl,Src}) ->
{bs_put,F,{I,Fl},[Src]};
rename_instr({bs_put_utf16=I,F,Fl,Src}) ->
{bs_put,F,{I,Fl},[Src]};
rename_instr({bs_put_utf32=I,F,Fl,Src}) ->
{bs_put,F,{I,Fl},[Src]};
rename_instr({bs_put_string,_,_}=I) ->
{bs_put,{f,0},I,[]};
rename_instr({bs_add=I,F,[Src1,Src2,U],Dst}) when is_integer(U) ->
{bif,I,F,[Src1,Src2,{integer,U}],Dst};
rename_instr({bs_utf8_size=I,F,Src,Dst}) ->
{bif,I,F,[Src],Dst};
rename_instr({bs_utf16_size=I,F,Src,Dst}) ->
{bif,I,F,[Src],Dst};
rename_instr({bs_init2=I,F,Sz,Extra,Live,Flags,Dst}) ->
{bs_init,F,{I,Extra,Flags},Live,[Sz],Dst};
rename_instr({bs_init_bits=I,F,Sz,Extra,Live,Flags,Dst}) ->
{bs_init,F,{I,Extra,Flags},Live,[Sz],Dst};
rename_instr({bs_append=I,F,Sz,Extra,Live,U,Src,Flags,Dst}) ->
{bs_init,F,{I,Extra,U,Flags},Live,[Sz,Src],Dst};
rename_instr({bs_private_append=I,F,Sz,U,Src,Flags,Dst}) ->
{bs_init,F,{I,U,Flags},none,[Sz,Src],Dst};
rename_instr(bs_init_writable=I) ->
{bs_init,{f,0},I,1,[{x,0}],{x,0}};
rename_instr({test,Op,F,[Ctx,Bits,{string,Str}]}) ->
%% When compiling from a .S file.
<<Bs:Bits/bits,_/bits>> = list_to_binary(Str),
{test,Op,F,[Ctx,Bs]};
rename_instr({put_map_assoc,Fail,S,D,R,L}) ->
{put_map,Fail,assoc,S,D,R,L};
rename_instr({put_map_exact,Fail,S,D,R,L}) ->
{put_map,Fail,exact,S,D,R,L};
rename_instr({test,has_map_fields,Fail,Src,{list,List}}) ->
{test,has_map_fields,Fail,[Src|List]};
rename_instr({test,is_nil,Fail,[Src]}) ->
{test,is_eq_exact,Fail,[Src,nil]};
rename_instr({select_val=I,Reg,Fail,{list,List}}) ->
{select,I,Reg,Fail,List};
rename_instr({select_tuple_arity=I,Reg,Fail,{list,List}}) ->
{select,I,Reg,Fail,List};
rename_instr(send) ->
{call_ext,2,send};
rename_instr(I) -> I.
coalesce_consecutive_labels([{label,L}=Lbl,{label,Alias}|Is], Replace, Acc) ->
coalesce_consecutive_labels([Lbl|Is], [{Alias,L}|Replace], Acc);
coalesce_consecutive_labels([I|Is], Replace, Acc) ->
coalesce_consecutive_labels(Is, Replace, [I|Acc]);
coalesce_consecutive_labels([], Replace, Acc) ->
D = maps:from_list(Replace),
beam_utils:replace_labels(Acc, [], D, fun(L) -> L end).
