gcc/lists.c

   1 /* List management for the GCC expander.
   2    Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2003, 2004, 2005, 2006 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, 51 Franklin Street, Fifth Floor, Boston, MA
  20 02110-1301, 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 (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 /* This function will free an entire list of either EXPR_LIST, INSN_LIST
  41    or DEPS_LIST nodes.  This is to be used only on lists that consist
  42    exclusively of nodes of one type only.  This is only called by
  43    free_EXPR_LIST_list, free_INSN_LIST_list and free_DEPS_LIST_list.  */
  44 static void
  45 free_list (rtx *listp, rtx *unused_listp)
  46 {
  47   rtx link, prev_link;
  48
  49   prev_link = *listp;
  50   link = XEXP (prev_link, 1);
  51
  52   gcc_assert (unused_listp != &unused_insn_list
  53               || GET_CODE (prev_link) == INSN_LIST);
  54
  55   while (link)
  56     {
  57       gcc_assert (unused_listp != &unused_insn_list
  58                   || GET_CODE (prev_link) == INSN_LIST);
  59
  60       prev_link = link;
  61       link = XEXP (link, 1);
  62     }
  63
  64   XEXP (prev_link, 1) = *unused_listp;
  65   *unused_listp = *listp;
  66   *listp = 0;
  67 }
  68
  69 /* Find corresponding to ELEM node in the list pointed to by LISTP.
  70    This node must exist in the list.  Returns pointer to that node.  */
  71 static rtx *
  72 find_list_elem (rtx elem, rtx *listp)
  73 {
  74   while (XEXP (*listp, 0) != elem)
  75     listp = &XEXP (*listp, 1);
  76   return listp;
  77 }
  78
  79 /* Remove the node pointed to by LISTP from the list.  */
  80 static void
  81 remove_list_node (rtx *listp)
  82 {
  83   rtx node;
  84
  85   node = *listp;
  86   *listp = XEXP (node, 1);
  87   XEXP (node, 1) = 0;
  88 }
  89
  90 /* Removes corresponding to ELEM node from the list pointed to by LISTP.
  91    Returns that node.  */
  92 rtx
  93 remove_list_elem (rtx elem, rtx *listp)
  94 {
  95   rtx node;
  96
  97   listp = find_list_elem (elem, listp);
  98   node = *listp;
  99   remove_list_node (listp);
 100   return node;
 101 }
 102
 103 /* This call is used in place of a gen_rtx_INSN_LIST. If there is a cached
 104    node available, we'll use it, otherwise a call to gen_rtx_INSN_LIST
 105    is made.  */
 106 rtx
 107 alloc_INSN_LIST (rtx val, rtx next)
 108 {
 109   rtx r;
 110
 111   if (unused_insn_list)
 112     {
 113       r = unused_insn_list;
 114       unused_insn_list = XEXP (r, 1);
 115       XEXP (r, 0) = val;
 116       XEXP (r, 1) = next;
 117       PUT_REG_NOTE_KIND (r, VOIDmode);
 118
 119       gcc_assert (GET_CODE (r) == INSN_LIST);
 120     }
 121   else
 122     r = gen_rtx_INSN_LIST (VOIDmode, val, next);
 123
 124   return r;
 125 }
 126
 127 /* This call is used in place of a gen_rtx_EXPR_LIST. If there is a cached
 128    node available, we'll use it, otherwise a call to gen_rtx_EXPR_LIST
 129    is made.  */
 130 rtx
 131 alloc_EXPR_LIST (int kind, rtx val, rtx next)
 132 {
 133   rtx r;
 134
 135   if (unused_expr_list)
 136     {
 137       r = unused_expr_list;
 138       unused_expr_list = XEXP (r, 1);
 139       XEXP (r, 0) = val;
 140       XEXP (r, 1) = next;
 141       PUT_REG_NOTE_KIND (r, kind);
 142     }
 143   else
 144     r = gen_rtx_EXPR_LIST (kind, val, next);
 145
 146   return r;
 147 }
 148
 149 /* This function will free up an entire list of EXPR_LIST nodes.  */
 150 void
 151 free_EXPR_LIST_list (rtx *listp)
 152 {
 153   if (*listp == 0)
 154     return;
 155   free_list (listp, &unused_expr_list);
 156 }
 157
 158 /* This function will free up an entire list of INSN_LIST nodes.  */
 159 void
 160 free_INSN_LIST_list (rtx *listp)
 161 {
 162   if (*listp == 0)
 163     return;
 164   free_list (listp, &unused_insn_list);
 165 }
 166
 167 /* This function will free up an individual EXPR_LIST node.  */
 168 void
 169 free_EXPR_LIST_node (rtx ptr)
 170 {
 171   XEXP (ptr, 1) = unused_expr_list;
 172   unused_expr_list = ptr;
 173 }
 174
 175 /* This function will free up an individual INSN_LIST node.  */
 176 void
 177 free_INSN_LIST_node (rtx ptr)
 178 {
 179   gcc_assert (GET_CODE (ptr) == INSN_LIST);
 180   XEXP (ptr, 1) = unused_insn_list;
 181   unused_insn_list = ptr;
 182 }
 183
 184 /* Remove and free corresponding to ELEM node in the INSN_LIST pointed to
 185    by LISTP.  */
 186 void
 187 remove_free_INSN_LIST_elem (rtx elem, rtx *listp)
 188 {
 189   free_INSN_LIST_node (remove_list_elem (elem, listp));
 190 }
 191
 192 #include "gt-lists.h"