arch/x86/opt/x86_opt_util.ml

   1 (*
   2    Utilities for optimizations
   3    Copyright (C) 2001 Justin David Smith, Caltech
   4
   5    This program is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU General Public License
   7    as published by the Free Software Foundation; either version 2
   8    of the License, or (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software
  17    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  *)
  19 open Flags
  20
  21 open Frame_type
  22 open X86_inst_type
  23 open X86_frame_type
  24 open X86_frame
  25 open X86_util
  26
  27
  28 (***  Registers and Operands  ***)
  29
  30
  31 (* regs_in_operand
  32    Identify registers _used_ in an operand.  This for some reason
  33    appears to not be consistent with src_regs; at any rate, we need
  34    this computation for AGI.  *)
  35 let regs_in_operand = function
  36    ImmediateNumber _
  37  | ImmediateLabel _
  38  | FPStack _ ->
  39       []
  40  | Register r
  41  | FloatRegister r
  42  | MMXRegister r
  43  | MemReg r
  44  | MemRegOff (r, _) ->
  45       [r]
  46  | MemRegRegOffMul (r1, r2, _, _) ->
  47       [r1; r2]
  48  | SpillRegister _ ->
  49       [ebp]
  50
  51
  52 (* reg_in_operand
  53    Returns true if the register named appears in the operand *)
  54 let reg_in_operand op r =
  55    List.mem r (regs_in_operand op)
  56
  57
  58 (* is_fpstack
  59    Returns true if the operand indicated is an FPStack register *)
  60 let is_fpstack = function
  61    FPStack _ -> true
  62  | _ -> false
  63
  64
  65 (***  Liveness  ***)
  66
  67
  68 (* make_comment_string
  69    Builds a comment that is placed immediately (before, after) the
  70    instruction given (this is to ensure live-out and depth are ok.  *)
  71 let make_comment_string inst s =
  72    { live_src   = [];
  73      live_dst   = [];
  74      live_out   = inst.live_out;
  75      live_class = CodeNormal;
  76      live_depth = inst.live_depth;
  77      live_inst  = CommentString s;
  78    }
  79
  80
  81 (* make_comment_inst
  82    Similar to above, but build a CommentInst instead.  *)
  83 let make_comment_inst inst s =
  84    { live_src   = [];
  85      live_dst   = [];
  86      live_out   = inst.live_out;
  87      live_class = CodeNormal;
  88      live_depth = inst.live_depth;
  89      live_inst  = CommentInst (s, inst.live_inst);
  90    }
  91
  92
  93 let () = std_flags_help_section_text "opt.x86"
  94    "Optimizations specific to the X86 backend."