gcc/lists.c

   1 /* List management for the GCC expander.
   2    Copyright (C) 1987-2021 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #include "config.h"
  21 #include "system.h"
  22 #include "coretypes.h"
  23 #include "tm.h"
  24 #include "rtl.h"
  25
  26 static void free_list (rtx *, rtx *);
  27
  28 /* Functions for maintaining cache-able lists of EXPR_LIST and INSN_LISTs.  */
  29
  30 /* An INSN_LIST containing all INSN_LISTs allocated but currently unused.  */
  31 static GTY ((deletable)) rtx unused_insn_list;
  32
  33 /* An EXPR_LIST containing all EXPR_LISTs allocated but currently unused.  */
  34 static GTY ((deletable)) rtx unused_expr_list;
  35
  36 /* This function will free an entire list of either EXPR_LIST, INSN_LIST
  37    or DEPS_LIST nodes.  This is to be used only on lists that consist
  38    exclusively of nodes of one type only.  This is only called by
  39    free_EXPR_LIST_list, free_INSN_LIST_list and free_DEPS_LIST_list.  */
  40 static void
  41 free_list (rtx *listp, rtx *unused_listp)
  42 {
  43   rtx link, prev_link;
  44
  45   prev_link = *listp;
  46   link = XEXP (prev_link, 1);
  47
  48   gcc_assert (unused_listp != &unused_insn_list
  49               || GET_CODE (prev_link) == INSN_LIST);
  50
  51   while (link)
  52     {
  53       gcc_assert (unused_listp != &unused_insn_list
  54                   || GET_CODE (prev_link) == INSN_LIST);
  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 /* Find corresponding to ELEM node in the list pointed to by LISTP.
  66    This node must exist in the list.  Returns pointer to that node.  */
  67 static rtx *
  68 find_list_elem (rtx elem, rtx *listp)
  69 {
  70   while (XEXP (*listp, 0) != elem)
  71     listp = &XEXP (*listp, 1);
  72   return listp;
  73 }
  74
  75 /* Remove the node pointed to by LISTP from the list.  */
  76 static void
  77 remove_list_node (rtx *listp)
  78 {
  79   rtx node;
  80
  81   node = *listp;
  82   *listp = XEXP (node, 1);
  83   XEXP (node, 1) = 0;
  84 }
  85
  86 /* Removes corresponding to ELEM node from the list pointed to by LISTP.
  87    Returns that node.  */
  88 rtx
  89 remove_list_elem (rtx elem, rtx *listp)
  90 {
  91   rtx node;
  92
  93   listp = find_list_elem (elem, listp);
  94   node = *listp;
  95   remove_list_node (listp);
  96   return node;
  97 }
  98
  99 /* This call is used in place of a gen_rtx_INSN_LIST. If there is a cached
 100    node available, we'll use it, otherwise a call to gen_rtx_INSN_LIST
 101    is made.  */
 102 rtx_insn_list *
 103 alloc_INSN_LIST (rtx val, rtx next)
 104 {
 105   rtx_insn_list *r;
 106
 107   if (unused_insn_list)
 108     {
 109       r = as_a <rtx_insn_list *> (unused_insn_list);
 110       unused_insn_list = r->next ();
 111       XEXP (r, 0) = val;
 112       XEXP (r, 1) = next;
 113       PUT_REG_NOTE_KIND (r, VOIDmode);
 114
 115       gcc_assert (GET_CODE (r) == INSN_LIST);
 116     }
 117   else
 118     r = gen_rtx_INSN_LIST (VOIDmode, val, next);
 119
 120   return r;
 121 }
 122
 123 /* This call is used in place of a gen_rtx_EXPR_LIST. If there is a cached
 124    node available, we'll use it, otherwise a call to gen_rtx_EXPR_LIST
 125    is made.  */
 126 rtx_expr_list *
 127 alloc_EXPR_LIST (int kind, rtx val, rtx next)
 128 {
 129   rtx_expr_list *r;
 130
 131   if (unused_expr_list)
 132     {
 133       r = as_a <rtx_expr_list *> (unused_expr_list);
 134       unused_expr_list = XEXP (r, 1);
 135       XEXP (r, 0) = val;
 136       XEXP (r, 1) = next;
 137       PUT_REG_NOTE_KIND (r, kind);
 138     }
 139   else
 140     r = gen_rtx_EXPR_LIST ((machine_mode) kind, val, next);
 141
 142   return r;
 143 }
 144
 145 /* This function will free up an entire list of EXPR_LIST nodes.  */
 146 void
 147 free_EXPR_LIST_list (rtx_expr_list **listp)
 148 {
 149   if (*listp == 0)
 150     return;
 151   free_list ((rtx *)listp, &unused_expr_list);
 152 }
 153
 154 /* This function will free up an entire list of INSN_LIST nodes.  */
 155 void
 156 free_INSN_LIST_list (rtx_insn_list **listp)
 157 {
 158   if (*listp == 0)
 159     return;
 160   free_list ((rtx *)listp, &unused_insn_list);
 161 }
 162
 163 /* Make a copy of the INSN_LIST list LINK and return it.  */
 164 rtx_insn_list *
 165 copy_INSN_LIST (rtx_insn_list *link)
 166 {
 167   rtx_insn_list *new_queue;
 168   rtx_insn_list **pqueue = &new_queue;
 169
 170   for (; link; link = link->next ())
 171     {
 172       rtx_insn *x = link->insn ();
 173       rtx_insn_list *newlink = alloc_INSN_LIST (x, NULL);
 174       *pqueue = newlink;
 175       pqueue = (rtx_insn_list **)&XEXP (newlink, 1);
 176     }
 177   *pqueue = NULL;
 178   return new_queue;
 179 }
 180
 181 /* Duplicate the INSN_LIST elements of COPY and prepend them to OLD.  */
 182 rtx_insn_list *
 183 concat_INSN_LIST (rtx_insn_list *copy, rtx_insn_list *old)
 184 {
 185   rtx_insn_list *new_rtx = old;
 186   for (; copy ; copy = copy->next ())
 187     {
 188       new_rtx = alloc_INSN_LIST (copy->insn (), new_rtx);
 189       PUT_REG_NOTE_KIND (new_rtx, REG_NOTE_KIND (copy));
 190     }
 191   return new_rtx;
 192 }
 193
 194 /* This function will free up an individual EXPR_LIST node.  */
 195 void
 196 free_EXPR_LIST_node (rtx ptr)
 197 {
 198   XEXP (ptr, 1) = unused_expr_list;
 199   unused_expr_list = ptr;
 200 }
 201
 202 /* This function will free up an individual INSN_LIST node.  */
 203 void
 204 free_INSN_LIST_node (rtx ptr)
 205 {
 206   gcc_assert (GET_CODE (ptr) == INSN_LIST);
 207   XEXP (ptr, 1) = unused_insn_list;
 208   unused_insn_list = ptr;
 209 }
 210
 211 /* Remove and free corresponding to ELEM node in the INSN_LIST pointed to
 212    by LISTP.  */
 213 void
 214 remove_free_INSN_LIST_elem (rtx_insn *elem, rtx_insn_list **listp)
 215 {
 216   free_INSN_LIST_node (remove_list_elem (elem, (rtx *)listp));
 217 }
 218
 219 /* Remove and free the first node in the INSN_LIST pointed to by LISTP.  */
 220 rtx_insn *
 221 remove_free_INSN_LIST_node (rtx_insn_list **listp)
 222 {
 223   rtx_insn_list *node = *listp;
 224   rtx_insn *elem = node->insn ();
 225
 226   remove_list_node ((rtx *)listp);
 227   free_INSN_LIST_node (node);
 228
 229   return elem;
 230 }
 231
 232 /* Remove and free the first node in the EXPR_LIST pointed to by LISTP.  */
 233 rtx
 234 remove_free_EXPR_LIST_node (rtx_expr_list **listp)
 235 {
 236   rtx_expr_list *node = *listp;
 237   rtx elem = XEXP (node, 0);
 238
 239   remove_list_node ((rtx *)listp);
 240   free_EXPR_LIST_node (node);
 241
 242   return elem;
 243 }
 244
 245 #include "gt-lists.h"