hipe_x86_x87.erl

OTP是开放电信平台的简称

    case ?HIPE_X86_REGISTERS:is_precoloured(Reg) of
      true ->
	Temp = hipe_x86:mk_new_temp('untagged'),
	{[hipe_x86:mk_move(Src,Temp)], Temp};
      _ ->
	{[], Src}
    end,
  {PushOp, [_|NewMap0]} = push(NewSrc, Map),
  %% We want Dst in the map rather than NewSrc.
  NewMap = [Dst|NewMap0],
  case length(PushOp) of
    1 -> %% No popping of memory object on fpstack
      {Move++[hipe_x86:mk_fp_unop(fild, NewSrc)], NewMap};
    _ -> %% H contains pop instructions. Must be kept!
      Head = butlast(PushOp),
      {Move ++ Head ++ [hipe_x86:mk_fp_unop(fild, NewSrc)], NewMap}
  end.


do_fp_unop(I = #fp_unop{arg=Arg, op=fchs}, Liveout, Map) ->
  %% This is fchs, the only operation without a
  %% popping version. Needs special handling.
  case is_liveOut(Arg, Liveout) of
    true ->
      {SwitchIns, NewMap} = switch_first(Arg, Map),
      {SwitchIns ++ [I#fp_unop{arg=[]}], NewMap};
    false ->
      %% Don't need to keep this instruction!
      %% However, we may need to pop Src from the stack.
      case in_map(Arg, Map) of
	true ->
	  {SwitchInsn, NewMap0} = switch_first(Arg, Map),
	  NewMap = pop(NewMap0),
	  {SwitchInsn ++ pop_insn(), NewMap};
	_ ->
	  {[],Map}
      end
  end.

do_fp_binop(#fp_binop{src=Src, dst=Dst, op=Op},
       LiveOut, Map) ->
  case {is_liveOut(Src, LiveOut), is_liveOut(Dst, LiveOut)} of
    {true, true} ->
      keep_both(Op, Src, Dst, Map);
    {true, false} ->
      keep_src(Op, Src, Dst, Map);
    {false, true} ->
      keep_dst(Op, Src, Dst, Map);
    {false, false} ->
      %% Both Dst and Src are popped.
      keep_none(Op, Src, Dst, Map)
  end.

keep_both(Op, Src, Dst, Map) ->
  %% Keep both Dst and Src if it is there.
  {SwitchInsn, NewMap} = switch_first(Dst, Map),
  NewSrc = get_new_opnd(Src, NewMap),
  Insn = format_fp_binop(Op, NewSrc, mk_st(0)),
  {SwitchInsn++Insn, NewMap}.

keep_src(Op, Src, Dst, Map) ->
  %% Pop Dst but keep Src in stack if it is there.
  {SwitchInsn, NewMap0} = switch_first(Dst, Map),
  NewSrc = get_new_opnd(Src, NewMap0),
  NewMap = pop(NewMap0),
  Insn = format_fp_binop(Op, NewSrc, mk_st(0)),
  {SwitchInsn ++ Insn ++ pop_insn(), NewMap}.

keep_dst(Op, Src, Dst, Map) ->
  %% Keep Dst but pop Src.
  %% Dst must be in stack.
  DstInMap = in_map(Dst, Map),
  SrcInMap = in_map(Src, Map),
  case SrcInMap of
    true ->
      case DstInMap of
	true ->
	  %% Src must be popped. If Dst is on top of the stack we can
	  %% alter the operation rather than shuffle the stack.
	  {SwitchInsn, Insn, NewMap} =
	    if hd(Map) =:= Dst ->
		NewOp = mk_op_pop(reverse_op(Op)),
		NewDst = get_new_opnd(Src, Map),
		TmpMap = lists:map(fun(X) ->
				     if X =:= Src -> Dst; true -> X end
				   end, Map),
		{[], format_fp_binop(NewOp, mk_st(0), NewDst), pop(TmpMap)};
	       true ->
		{SwitchInsn1, NewMap0} = switch_first(Src, Map),
		NewDst = get_new_opnd(Dst,NewMap0),
		NewOp = mk_op_pop(Op),
		{SwitchInsn1,format_fp_binop(NewOp, mk_st(0), NewDst), pop(NewMap0)}
	    end,
	  {SwitchInsn ++ Insn, NewMap};
	_ ->
	  %% Src is on the stack, but Dst isn't. Use memory command to avoid
	  %% unnecessary loading instructions.
	  {SwitchInsn, NewMap0} = switch_first(Src, Map),
	  NewOp = reverse_op(Op),
	  NewMap = [Dst] ++ tl(NewMap0),
	  Insn = format_fp_binop(NewOp, Dst, mk_st(0)),
	  {SwitchInsn ++ Insn, NewMap}
      end;
    _ ->
      %% Src isn't in the map so it doesn't have to be popped.
      {SwitchInsn, NewMap} = switch_first(Dst, Map),
      {SwitchInsn ++ [#fp_unop{arg=Src,op=Op}], NewMap}
  end.

keep_none(Op, Src, Dst, Map) ->
  %% Dst must be on stack.
  {PushInsn, NewMap0} = 
    case in_map(Dst, Map) of
      true -> {[], Map};
      _ -> push(Dst, Map)
    end,
  case in_map(Src, NewMap0) of
    true ->
      %% Src must be popped.
      {SwitchInsn1, NewMap1} = switch_first(Src, NewMap0),
      NewOp = mk_op_pop(Op),
      NewDst = get_new_opnd(Dst,NewMap1),
      NewMap2 = pop(NewMap1),
      %% Then Dst has to be popped.
      {PopInsn,NewMap} = pop_member(Dst,NewMap2),
      Insn = format_fp_binop(NewOp, mk_st(0), NewDst),
      {PushInsn ++ SwitchInsn1 ++ Insn ++ PopInsn, NewMap};
    _ ->
      %% Src isn't in the map so it doesn't have to be popped.
      {SwitchInsn, NewMap1} = switch_first(Dst, NewMap0),
      NewMap = pop(NewMap1),
      {SwitchInsn ++ [#fp_unop{arg=Src,op=Op}] ++ pop_insn(), NewMap}
  end.

format_fp_binop(Op, Src=#x86_temp{}, Dst=#x86_fpreg{reg=Reg}) ->
  %% Handle that st(0) is sometimes implicit.
  if Reg =:= 0 -> [hipe_x86:mk_fp_unop(Op, Src)];
     true -> [hipe_x86:mk_fp_binop(Op, Src, Dst)]
  end;
format_fp_binop(Op, Src, Dst) ->
  [hipe_x86:mk_fp_binop(Op, Src, Dst)].

in_map(X, Map) ->
  lists:member(X, Map).

push_list(L, Map) ->
  push_list(L, Map, []).
push_list([H|T], Map, Acc) ->
  {Insn, NewMap} = push(H,Map),
  push_list(T, NewMap, Acc++Insn);
push_list([], Map, Acc) ->
  {Acc, Map}.

push(X, Map0) ->
  {PopInsn, Map} = 
    if length(Map0) > 7 -> pop_a_temp(Map0);
       true -> {[], Map0}
    end,
  NewX = get_new_opnd(X,Map),
  NewMap = [X | Map],
  PushOp = [hipe_x86:mk_fp_unop(fld, NewX)],
  {PopInsn ++ PushOp, NewMap}.

pop([_|Map]) ->
  Map.

pop_insn() ->
  [hipe_x86:mk_fp_unop('fstp',mk_st(0))].

pop_dead(Dead, Map) ->
  Dead0 = [X || X <- Map, lists:member(X,Dead)],
  pop_dead(Dead0, Map, []).

pop_dead([D|Dead], Map, Code) ->
  {I, NewMap0} = switch_first(D, Map),
  NewMap = pop(NewMap0),
  Store = case D of
	    #x86_temp{} -> [hipe_x86:mk_fp_unop('fstp', D)];
	    _ -> pop_insn()
	  end,
  pop_dead(Dead, NewMap, Code++I++Store);
pop_dead([], Map, Code) ->
  {Code,Map}.

pop_all(Map) ->
  {Code, _} = pop_dead(Map, Map),
  Code.

pop_member(Member, Map) ->
  {Head,[_|T]} = lists:splitwith(fun(X)->X/=Member end,Map),
  {[hipe_x86:mk_fp_unop('fstp', mk_st(get_pos(Member, Map, 0)))],
   Head++T}.

pop_a_temp(Map) ->
  Temp = find_a_temp(Map),
  {SwitchInsn, NewMap0} = switch_first(Temp, Map),
  NewMap = pop(NewMap0),
  {SwitchInsn ++ [hipe_x86:mk_fp_unop('fstp', Temp)], NewMap}.

find_a_temp([H = #x86_temp{}|_]) ->
  H;
find_a_temp([_|T]) ->
  find_a_temp(T);
find_a_temp([]) ->
  ?EXIT({noTempOnFPStack,{}}).

switch_first(X, Map = [H|_]) ->
  Pos = get_pos(X, Map, 0),
  case Pos of
    0 -> 
      {[], Map};
    notFound ->
      push(X, Map);
    _ ->	    
      {[_|Head], [_|Tail]} = lists:splitwith(fun(Y)->Y/=X end, Map),
      NewMap = [X|Head] ++ [H|Tail],
      Ins = hipe_x86:mk_fp_unop(fxch, mk_st(Pos)),
      {[Ins], NewMap}
  end;
switch_first(X, Map) ->
  push(X, Map).

get_pos(X, [H|T], Pos) ->
  if X =:= H -> Pos;
     true -> get_pos(X, T, Pos+1)
  end;
get_pos(_, [], _) ->
  notFound.

get_new_opnd(X, Map) ->
  I = get_pos(X, Map, 0),
  case I of
    notFound ->
      %% The operand is probably a spilled float.
      X;
    _ ->
      mk_st(I)
  end.

is_fp(#x86_fpreg{}) ->
  true;
is_fp(#x86_mem{type=Type}) ->
  Type =:= 'double';
is_fp(#x86_temp{type=Type}) ->
  Type =:= 'double'.

handle_insn(I) ->
  case I of
    #fmove{} -> true;
    #fp_unop{} -> true;
    #fp_binop{} -> true;
    #pseudo_call{}->true;
%%    #ret{}-> true;
    _ -> false
  end.

is_liveOut(X, LiveOut) ->
  ordsets:is_element(X, LiveOut).

mk_st(X) ->
  hipe_x86:mk_fpreg(X, false).

reverse_op(Op) ->
  case Op of
    'fsub' -> 'fsubr';
    'fdiv' -> 'fdivr';
    'fsubr'-> 'fsub';
    'fdivr' -> 'fdiv';
    _ -> Op
  end.

mk_op_pop(Op) ->
  case Op of
    'fadd'-> 'faddp';
    'fdiv' -> 'fdivp';
    'fdivr' -> 'fdivrp';
    'fmul' -> 'fmulp';
    'fsub' -> 'fsubp';
    'fsubr' -> 'fsubrp';
    _ -> ?EXIT({operandHasNoPopVariant,{Op}})
  end.

butlast([X|Xs]) -> butlast(Xs,X).

butlast([],_) -> [];
butlast([X|Xs],Y) -> [Y|butlast(Xs,X)].

%%pp_insn(Op, Src, Dst) ->
%%  pp([hipe_x86:mk_fp_binop(Op, Src, Dst)]).

%%pp([I|Ins]) ->
%%  hipe_x86_pp:pp_insn(I),
%%  pp(Ins);
%%pp([]) ->
%%  [].

pseudo_pop(Map) when length(Map) > 0 ->
  Dst = hipe_x86:mk_new_temp('double'),
  pseudo_pop(Dst, length(Map), []);
pseudo_pop(_) ->
  [].

pseudo_pop(Dst, St, Acc) when St > 1 ->
%% Store all members of the stack to a single temporary to force 
%% any floating point overflow exceptions to occur even though we
%% don't have overflow for the extended double precision in the x87.
  pseudo_pop(Dst, St-1, 
	     [hipe_x86:mk_fp_unop('fxch', mk_st(St-1)),
	      hipe_x86:mk_fp_unop('fst', Dst),
	      hipe_x86:mk_fp_unop('fxch', mk_st(St-1))
	      |Acc]);
pseudo_pop(Dst, _St, Acc) ->
  [hipe_x86:mk_fp_unop('fst', Dst)|Acc].