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, 2007, 2008, 2009
   4    Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "diagnostic-core.h"
  27 #include "toplev.h"
  28 #include "rtl.h"
  29 #include "ggc.h"
  30
  31 static void free_list (rtx *, rtx *);
  32
  33 /* Functions for maintaining cache-able lists of EXPR_LIST and INSN_LISTs.  */
  34
  35 /* An INSN_LIST containing all INSN_LISTs allocated but currently unused.  */
  36 static GTY ((deletable)) rtx unused_insn_list;
  37
  38 /* An EXPR_LIST containing all EXPR_LISTs allocated but currently unused.  */
  39 static GTY ((deletable)) rtx unused_expr_list;
  40
  41 /* This function will free an entire list of either EXPR_LIST, INSN_LIST
  42    or DEPS_LIST nodes.  This is to be used only on lists that consist
  43    exclusively of nodes of one type only.  This is only called by
  44    free_EXPR_LIST_list, free_INSN_LIST_list and free_DEPS_LIST_list.  */
  45 static void
  46 free_list (rtx *listp, rtx *unused_listp)
  47 {
  48   rtx link, prev_link;
  49
  50   prev_link = *listp;
  51   link = XEXP (prev_link, 1);
  52
  53   gcc_assert (unused_listp != &unused_insn_list
  54               || GET_CODE (prev_link) == INSN_LIST);
  55
  56   while (link)
  57     {
  58       gcc_assert (unused_listp != &unused_insn_list
  59                   || GET_CODE (prev_link) == INSN_LIST);
  60
  61       prev_link = link;
  62       link = XEXP (link, 1);
  63     }
  64
  65   XEXP (prev_link, 1) = *unused_listp;
  66   *unused_listp = *listp;
  67   *listp = 0;
  68 }
  69
  70 /* Find corresponding to ELEM node in the list pointed to by LISTP.
  71    This node must exist in the list.  Returns pointer to that node.  */
  72 static rtx *
  73 find_list_elem (rtx elem, rtx *listp)
  74 {
  75   while (XEXP (*listp, 0) != elem)
  76     listp = &XEXP (*listp, 1);
  77   return listp;
  78 }
  79
  80 /* Remove the node pointed to by LISTP from the list.  */
  81 static void
  82 remove_list_node (rtx *listp)
  83 {
  84   rtx node;
  85
  86   node = *listp;
  87   *listp = XEXP (node, 1);
  88   XEXP (node, 1) = 0;
  89 }
  90
  91 /* Removes corresponding to ELEM node from the list pointed to by LISTP.
  92    Returns that node.  */
  93 rtx
  94 remove_list_elem (rtx elem, rtx *listp)
  95 {
  96   rtx node;
  97
  98   listp = find_list_elem (elem, listp);
  99   node = *listp;
 100   remove_list_node (listp);
 101   return node;
 102 }
 103
 104 /* This call is used in place of a gen_rtx_INSN_LIST. If there is a cached
 105    node available, we'll use it, otherwise a call to gen_rtx_INSN_LIST
 106    is made.  */
 107 rtx
 108 alloc_INSN_LIST (rtx val, rtx next)
 109 {
 110   rtx r;
 111
 112   if (unused_insn_list)
 113     {
 114       r = unused_insn_list;
 115       unused_insn_list = XEXP (r, 1);
 116       XEXP (r, 0) = val;
 117       XEXP (r, 1) = next;
 118       PUT_REG_NOTE_KIND (r, VOIDmode);
 119
 120       gcc_assert (GET_CODE (r) == INSN_LIST);
 121     }
 122   else
 123     r = gen_rtx_INSN_LIST (VOIDmode, val, next);
 124
 125   return r;
 126 }
 127
 128 /* This call is used in place of a gen_rtx_EXPR_LIST. If there is a cached
 129    node available, we'll use it, otherwise a call to gen_rtx_EXPR_LIST
 130    is made.  */
 131 rtx
 132 alloc_EXPR_LIST (int kind, rtx val, rtx next)
 133 {
 134   rtx r;
 135
 136   if (unused_expr_list)
 137     {
 138       r = unused_expr_list;
 139       unused_expr_list = XEXP (r, 1);
 140       XEXP (r, 0) = val;
 141       XEXP (r, 1) = next;
 142       PUT_REG_NOTE_KIND (r, kind);
 143     }
 144   else
 145     r = gen_rtx_EXPR_LIST ((enum machine_mode) kind, val, next);
 146
 147   return r;
 148 }
 149
 150 /* This function will free up an entire list of EXPR_LIST nodes.  */
 151 void
 152 free_EXPR_LIST_list (rtx *listp)
 153 {
 154   if (*listp == 0)
 155     return;
 156   free_list (listp, &unused_expr_list);
 157 }
 158
 159 /* This function will free up an entire list of INSN_LIST nodes.  */
 160 void
 161 free_INSN_LIST_list (rtx *listp)
 162 {
 163   if (*listp == 0)
 164     return;
 165   free_list (listp, &unused_insn_list);
 166 }
 167
 168 /* This function will free up an individual EXPR_LIST node.  */
 169 void
 170 free_EXPR_LIST_node (rtx ptr)
 171 {
 172   XEXP (ptr, 1) = unused_expr_list;
 173   unused_expr_list = ptr;
 174 }
 175
 176 /* This function will free up an individual INSN_LIST node.  */
 177 void
 178 free_INSN_LIST_node (rtx ptr)
 179 {
 180   gcc_assert (GET_CODE (ptr) == INSN_LIST);
 181   XEXP (ptr, 1) = unused_insn_list;
 182   unused_insn_list = ptr;
 183 }
 184
 185 /* Remove and free corresponding to ELEM node in the INSN_LIST pointed to
 186    by LISTP.  */
 187 void
 188 remove_free_INSN_LIST_elem (rtx elem, rtx *listp)
 189 {
 190   free_INSN_LIST_node (remove_list_elem (elem, listp));
 191 }
 192
 193 /* Remove and free the first node in the INSN_LIST pointed to by LISTP.  */
 194 rtx
 195 remove_free_INSN_LIST_node (rtx *listp)
 196 {
 197   rtx node = *listp;
 198   rtx elem = XEXP (node, 0);
 199
 200   remove_list_node (listp);
 201   free_INSN_LIST_node (node);
 202
 203   return elem;
 204 }
 205
 206 /* Remove and free the first node in the EXPR_LIST pointed to by LISTP.  */
 207 rtx
 208 remove_free_EXPR_LIST_node (rtx *listp)
 209 {
 210   rtx node = *listp;
 211   rtx elem = XEXP (node, 0);
 212
 213   remove_list_node (listp);
 214   free_EXPR_LIST_node (node);
 215
 216   return elem;
 217 }
 218
 219 #include "gt-lists.h"