hipe_icode_split_arith.erl

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%% -*- erlang-indent-level: 2 -*-
%%-------------------------------------------------------------------
%% File    : hipe_icode_split_arith.erl
%% Author  : Tobias Lindahl <[e-mail]>
%% Description : 
%%
%% Created : 12 Nov 2003 by Tobias Lindahl <[e-mail]>
%%-------------------------------------------------------------------
-module(hipe_icode_split_arith).

-export([cfg/3]).

-include("hipe_icode.hrl").

-define(MIN_RATIO, 0.005).

cfg(Cfg, _Fun, Options) ->
  Icode = hipe_icode_cfg:cfg_to_linear(Cfg),
  case proplists:get_bool(split_arith_unsafe, Options) of
    true -> make_split_unsafe(Icode);
    _ ->
      case preprocess(Icode) of
	{do_not_split, _Ratio} -> 
	  Cfg;
	{split, _Ratio, Icode1} ->
	  NewCfg = split(Icode1),
	  %%hipe_icode_cfg:pp(NewCfg),
	  NewCfg
      end
  end.

check_nofix_const([Arg1|Arg2]) ->
  case hipe_icode:is_const(Arg1) of
    true ->
      %%io:format("ConsTant.....~w",[Arg1]),
      Val1 = hipe_tagscheme:fixnum_val(hipe_icode:const_value(Arg1)),
      case hipe_tagscheme:is_fixnum(Val1) of
	true ->
	  check_nofix_const(Arg2);
	false -> {no}
      end;

    false ->
      check_nofix_const(Arg2)
  end;	  
check_nofix_const([]) -> true.

check_const([I|Left]) ->
  case I of
    #call{} ->
      case is_arith(I) of
	true -> %%io:format("is_arith.....~w",[I]),
	  Args = hipe_icode:call_args(I),
	  case check_nofix_const(Args) of
	    {no} -> {do_not_split};
	    _ -> check_const(Left)
	  end;
	_ -> check_const(Left)
      end;
    _ -> check_const(Left)
  end;
check_const([]) -> {yes}.


make_split_unsafe(Icode)->
  LinearCode = hipe_icode:icode_code(Icode),
  NewLinearCode = change_unsafe(LinearCode),
  NewIcode = hipe_icode:icode_code_update(Icode, NewLinearCode),
  hipe_icode_cfg:linear_to_cfg(NewIcode).

change_unsafe([I|Is]) ->
  case I of
    #call{} ->
      case is_arith_extra_unsafe(I) of
	true ->
	  NewOp = arithop_to_extra_unsafe(hipe_icode:call_fun(I)),
	  NewI1 = hipe_icode:call_fun_update(I, NewOp),
	  [NewI1|change_unsafe(Is)];
	false ->
	  [I|change_unsafe(Is)]
      end;
    _ ->
      [I|change_unsafe(Is)]
  end;
change_unsafe([]) -> [].

preprocess(Icode) ->
  LinearCode = hipe_icode:icode_code(Icode),
  case check_const(LinearCode) of
    {do_not_split} -> %%io:format("NO FIXNUM....."),
      {do_not_split, 1.9849 }; % Ratio val is ignored
    _ ->
      {NofArith, NofIns, NewLinearCode} = preprocess_code(LinearCode),
      case NofArith / NofIns of
	X when X >= ?MIN_RATIO ->
	  NewIcode = hipe_icode:icode_code_update(Icode, NewLinearCode),
	  {split, X, NewIcode};
	Y ->
	  {do_not_split, Y}
      end
  end.

preprocess_code([H|Code]) ->
  preprocess_code(Code, 0, 0, [H]).

preprocess_code([I|Left], NofArith, NofIns,CodeAcc = [PrevI|_])->
  case I of
    #call{} ->
      case is_arith(I) of
	true ->
	  %% Note that we need to put these instructions in a separate
	  %% basic block since we need the ability to fail to these
	  %% instructions, but also fail from them. The basic block
	  %% merger will take care of unnecessary splits.

	  %% If call is an arithmetic operation replace the operation
	  %% with the specified replacement operator.  
	  NewOp = arithop_to_split(hipe_icode:call_fun(I)),
	  NewI = hipe_icode:call_fun_update(I, NewOp),
	  case hipe_icode:is_label(PrevI) of
	    true ->
	      case (Left =:= []) orelse hipe_icode:is_label(hd(Left)) of
		true -> 
		  preprocess_code(Left, NofArith+1, NofIns+1, [NewI|CodeAcc]);
		false ->
		  NewLabel = hipe_icode:mk_new_label(),
		  NewLabelName = hipe_icode:label_name(NewLabel),
		  NewI1 = hipe_icode:call_set_continuation(NewI, NewLabelName),
		  preprocess_code(Left, NofArith+1, NofIns+1, 
				  [NewLabel, NewI1|CodeAcc])
	      end;
	    false ->
	      RevPreCode =
		case hipe_icode:is_branch(PrevI) of
		  true ->
		    [hipe_icode:mk_new_label()];
		  false ->
		    NewLabel1 = hipe_icode:mk_new_label(),
		    NewLabelName1 = hipe_icode:label_name(NewLabel1),
		    [NewLabel1, hipe_icode:mk_goto(NewLabelName1)]
		end,
	      case (Left =:= []) orelse hipe_icode:is_label(hd(Left)) of
		true -> 
		  preprocess_code(Left, NofArith+1, NofIns+1, 
				  [NewI|RevPreCode] ++ CodeAcc);
		false ->
		  NewLabel2 = hipe_icode:mk_new_label(),
		  NewLabelName2 = hipe_icode:label_name(NewLabel2),
		  NewI1 = hipe_icode:call_set_continuation(NewI, NewLabelName2),
		  preprocess_code(Left, NofArith+1, NofIns+1, 
				  [NewLabel2, NewI1|RevPreCode] ++ CodeAcc)
	      end
	  end;
	false ->
	  preprocess_code(Left, NofArith, NofIns + 1, [I|CodeAcc])
      end;
    #label{} ->
      %% Don't count labels as instructions.
      preprocess_code(Left, NofArith, NofIns, [I|CodeAcc]);
    _ ->
      preprocess_code(Left, NofArith, NofIns+1, [I|CodeAcc])
  end;
preprocess_code([], NofArith, NofIns, CodeAcc) ->
  {NofArith, NofIns, lists:reverse(CodeAcc)}.

split(Icode) ->
  LinearCode = hipe_icode:icode_code(Icode),
  %% create a new icode label for each existing icode label
  %% create mappings, NewToOld and OldToNew.
  %%
  AllLabels = lists:foldl(fun(I, Acc) ->
			      case hipe_icode:is_label(I) of
				true -> [hipe_icode:label_name(I)|Acc];
				false -> Acc
			      end
			  end, [], LinearCode),
  {OldToNewMap, NewToOldMap}  = new_label_maps(AllLabels),

  %% the call below doubles the number of basic blocks with the new
  %% labels instead of the old.

  NewLinearCode = map_code(LinearCode, OldToNewMap),
  NewIcode = hipe_icode:icode_code_update(Icode, NewLinearCode),
  NewCfg = hipe_icode_cfg:linear_to_cfg(NewIcode),
  NewCfg2 = 
    insert_tests(NewCfg, [gb_trees:get(X, OldToNewMap) || X<-AllLabels], 
		 NewToOldMap, OldToNewMap),
  %%io:format("split(Cfg): Inserting testsL Done\n", []),
  NewCfg2.


map_code(OldCode, LabelMap) ->
  AddedCode = map_code(OldCode, none, LabelMap, []),
  OldCode ++ AddedCode.

map_code([I|Left], ArithFail, LabelMap, Acc) ->
  case I of
    #call{} ->
      case is_arith(I) of
	true ->
	  case hipe_icode:defines(I) of
	    []->  
	      map_code(Left, ArithFail, LabelMap, [redirect(I, LabelMap)|Acc]);
	    _ ->
	      NewOp = split_to_unsafe(I),
	      NewI1 = hipe_icode:call_fun_update(I, NewOp),
	      NewI2 = redirect(NewI1, LabelMap),
	      NewI3 = hipe_icode:call_set_fail_label(NewI2, ArithFail),
	      map_code(Left, ArithFail, LabelMap, [NewI3|Acc])
	  end;
	false ->
	  map_code(Left, ArithFail, LabelMap, [redirect(I, LabelMap)|Acc])
      end;
    #label{} ->
      LabelName = hipe_icode:label_name(I),
      NewLabel = hipe_icode:mk_label(gb_trees:get(LabelName, LabelMap)),
      map_code(Left, LabelName, LabelMap, [NewLabel|Acc]);
    _ -> 
      map_code(Left, ArithFail, LabelMap, [redirect(I, LabelMap)|Acc])
  end;
map_code([], _ArithFail, _LabelMap, Acc) ->
  lists:reverse(Acc).

insert_tests(Cfg, Labels,NewToOldMap, OldToNewMap) ->
  InfoMap = infomap_init(Labels),
  %%io:format("insert_tests/3: Finding testpoints ...\n", []),
  NewInfoMap = find_testpoints(Cfg, Labels, InfoMap),
  %%io:format("insert_tests/3: Finding testpoints: Done\n", []),
  %%io:format("insert_tests/3: Infomap: ~w\n", [gb_trees:to_list(NewInfoMap)]),
  make_tests(Cfg, NewInfoMap, NewToOldMap, OldToNewMap).

find_testpoints(Cfg, Labels, InfoMap) ->
  case find_testpoints(Labels, InfoMap, Cfg, false) of
    {dirty, NewInfoMap} -> 
      %%io:format("find_testpoints/3: Looping\n", []),
      find_testpoints(Cfg, Labels, NewInfoMap);
    fixpoint ->
      InfoMap 
  end.

find_testpoints([Lbl|Left], InfoMap, Cfg, Dirty) ->
  Code = hipe_bb:code(hipe_icode_cfg:bb(Cfg, Lbl)),
  InfoOut = join_info(hipe_icode_cfg:succ(Cfg, Lbl), InfoMap),  
  OldInfoIn = infomap_get_all(Lbl, InfoMap),
  NewInfoIn = traverse_code(lists:reverse(Code), InfoOut),
  case (gb_sets:is_subset(OldInfoIn, NewInfoIn) andalso 
	gb_sets:is_subset(NewInfoIn, OldInfoIn)) of
    true ->
      find_testpoints(Left, InfoMap, Cfg, Dirty);
    false ->
      %%io:format("find_testpoints/4: Label: ~w: OldMap ~w\nNewMap: ~w\n", 
      %%	 [Lbl, gb_sets:to_list(OldInfoIn), gb_sets:to_list(NewInfoIn)]),
      NewInfoMap = gb_trees:update(Lbl, NewInfoIn, InfoMap),
      find_testpoints(Left, NewInfoMap, Cfg, true)
  end;
find_testpoints([], InfoMap, _Cfg, Dirty) ->
  if Dirty -> {dirty, InfoMap};
     true -> fixpoint
  end.

traverse_code([I|Left], Info) ->
  NewInfo = kill_defines(I, Info),
  case I of
    #call{} ->
      case is_unsafe_arith(I) of
	true ->
	  %% The dst is sure to be a fixnum. Remove the 'killed' mark.
	  Dst = hd(hipe_icode:call_dstlist(I)),