ocaml/asmcomp/i386/reload.ml

73 lines
2.4 KiB
OCaml

(***********************************************************************)
(* *)
(* Objective Caml *)
(* *)
(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
(* *)
(* Copyright 1996 Institut National de Recherche en Informatique et *)
(* en Automatique. All rights reserved. This file is distributed *)
(* under the terms of the Q Public License version 1.0. *)
(* *)
(***********************************************************************)
(* $Id$ *)
open Cmm
open Arch
open Reg
open Mach
(* Reloading for the Intel x86 *)
let stackp r =
match r.loc with
Stack _ -> true
| _ -> false
class reload = object (self)
inherit Reloadgen.reload_generic as super
method makereg r =
match r.typ with
Float -> r
| _ -> super#makereg r
(* By overriding makereg, we make sure that pseudoregs of type float
will never be reloaded. Hence there is no need to make special cases for
floating-point operations. *)
method reload_operation op arg res =
match op with
Iintop(Iadd|Isub|Imul|Iand|Ior|Ixor|Icomp _|Icheckbound) ->
(* One of the two arguments can reside in the stack *)
if stackp arg.(0) && stackp arg.(1)
then ([|arg.(0); self#makereg arg.(1)|], res)
else (arg, res)
| Iintop_imm(Iadd, _) when arg.(0).loc <> res.(0).loc ->
(* This add will be turned into a lea; args and results must be
in registers *)
super#reload_operation op arg res
| Iintop(Ilsl|Ilsr|Iasr) | Iintop_imm(_, _) | Ifloatofint | Iintoffloat |
Ispecific(Ipush) ->
(* The argument(s) can be either in register or on stack *)
(arg, res)
| _ -> (* Other operations: all args and results in registers *)
super#reload_operation op arg res
method reload_test tst arg =
match tst with
Iinttest cmp ->
(* One of the two arguments can reside on stack *)
if stackp arg.(0) && stackp arg.(1)
then [| self#makereg arg.(0); arg.(1) |]
else arg
| _ ->
(* The argument(s) can be either in register or on stack *)
arg
end
let fundecl f =
(new reload)#fundecl f