gcc/lists.c

   1 /* List management for the GNU C-Compiler expander.
   2    Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20 02111-1307, USA.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "toplev.h"
  27 #include "rtl.h"
  28 #include "ggc.h"
  29
  30 static void free_list PARAMS ((rtx *, rtx *));
  31
  32 /* Functions for maintaining cache-able lists of EXPR_LIST and INSN_LISTs.  */
  33
  34 /* An INSN_LIST containing all INSN_LISTs allocated but currently unused.  */
  35 static GTY ((deletable (""))) rtx unused_insn_list;
  36
  37 /* An EXPR_LIST containing all EXPR_LISTs allocated but currently unused.  */
  38 static GTY ((deletable (""))) rtx unused_expr_list;
  39
  40
  41 /* This function will free an entire list of either EXPR_LIST or INSN_LIST
  42    nodes. This is to be used only on lists that consist exclusively of
  43    nodes of one type only.  This is only called by free_EXPR_LIST_list
  44    and free_INSN_LIST_list.  */
  45 static void
  46 free_list (listp, unused_listp)
  47      rtx *listp, *unused_listp;
  48 {
  49   rtx link, prev_link;
  50
  51   prev_link = *listp;
  52   link = XEXP (prev_link, 1);
  53
  54   while (link)
  55     {
  56       prev_link = link;
  57       link = XEXP (link, 1);
  58     }
  59
  60   XEXP (prev_link, 1) = *unused_listp;
  61   *unused_listp = *listp;
  62   *listp = 0;
  63 }
  64
  65 /* This call is used in place of a gen_rtx_INSN_LIST. If there is a cached
  66    node available, we'll use it, otherwise a call to gen_rtx_INSN_LIST
  67    is made.  */
  68 rtx
  69 alloc_INSN_LIST (val, next)
  70      rtx val, next;
  71 {
  72   rtx r;
  73
  74   if (unused_insn_list)
  75     {
  76       r = unused_insn_list;
  77       unused_insn_list = XEXP (r, 1);
  78       XEXP (r, 0) = val;
  79       XEXP (r, 1) = next;
  80       PUT_REG_NOTE_KIND (r, VOIDmode);
  81     }
  82   else
  83     r = gen_rtx_INSN_LIST (VOIDmode, val, next);
  84
  85   return r;
  86 }
  87
  88 /* This call is used in place of a gen_rtx_EXPR_LIST. If there is a cached
  89    node available, we'll use it, otherwise a call to gen_rtx_EXPR_LIST
  90    is made.  */
  91 rtx
  92 alloc_EXPR_LIST (kind, val, next)
  93      int kind;
  94      rtx val, next;
  95 {
  96   rtx r;
  97
  98   if (unused_expr_list)
  99     {
 100       r = unused_expr_list;
 101       unused_expr_list = XEXP (r, 1);
 102       XEXP (r, 0) = val;
 103       XEXP (r, 1) = next;
 104       PUT_REG_NOTE_KIND (r, kind);
 105     }
 106   else
 107     r = gen_rtx_EXPR_LIST (kind, val, next);
 108
 109   return r;
 110 }
 111
 112 /* This function will free up an entire list of EXPR_LIST nodes.  */
 113 void
 114 free_EXPR_LIST_list (listp)
 115      rtx *listp;
 116 {
 117   if (*listp == 0)
 118     return;
 119   free_list (listp, &unused_expr_list);
 120 }
 121
 122 /* This function will free up an entire list of INSN_LIST nodes.  */
 123 void
 124 free_INSN_LIST_list (listp)
 125      rtx *listp;
 126 {
 127   if (*listp == 0)
 128     return;
 129   free_list (listp, &unused_insn_list);
 130 }
 131
 132 /* This function will free up an individual EXPR_LIST node.  */
 133 void
 134 free_EXPR_LIST_node (ptr)
 135      rtx ptr;
 136 {
 137   XEXP (ptr, 1) = unused_expr_list;
 138   unused_expr_list = ptr;
 139 }
 140
 141 /* This function will free up an individual INSN_LIST node.  */
 142 void
 143 free_INSN_LIST_node (ptr)
 144      rtx ptr;
 145 {
 146   XEXP (ptr, 1) = unused_insn_list;
 147   unused_insn_list = ptr;
 148 }
 149
 150 #include "gt-lists.h"