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 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 (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 (rtx *listp, rtx *unused_listp)
  47 {
  48   rtx link, prev_link;
  49
  50   prev_link = *listp;
  51   link = XEXP (prev_link, 1);
  52
  53   while (link)
  54     {
  55       prev_link = link;
  56       link = XEXP (link, 1);
  57     }
  58
  59   XEXP (prev_link, 1) = *unused_listp;
  60   *unused_listp = *listp;
  61   *listp = 0;
  62 }
  63
  64 /* This call is used in place of a gen_rtx_INSN_LIST. If there is a cached
  65    node available, we'll use it, otherwise a call to gen_rtx_INSN_LIST
  66    is made.  */
  67 rtx
  68 alloc_INSN_LIST (rtx val, rtx next)
  69 {
  70   rtx r;
  71
  72   if (unused_insn_list)
  73     {
  74       r = unused_insn_list;
  75       unused_insn_list = XEXP (r, 1);
  76       XEXP (r, 0) = val;
  77       XEXP (r, 1) = next;
  78       PUT_REG_NOTE_KIND (r, VOIDmode);
  79     }
  80   else
  81     r = gen_rtx_INSN_LIST (VOIDmode, val, next);
  82
  83   return r;
  84 }
  85
  86 /* This call is used in place of a gen_rtx_EXPR_LIST. If there is a cached
  87    node available, we'll use it, otherwise a call to gen_rtx_EXPR_LIST
  88    is made.  */
  89 rtx
  90 alloc_EXPR_LIST (int kind, rtx val, rtx next)
  91 {
  92   rtx r;
  93
  94   if (unused_expr_list)
  95     {
  96       r = unused_expr_list;
  97       unused_expr_list = XEXP (r, 1);
  98       XEXP (r, 0) = val;
  99       XEXP (r, 1) = next;
 100       PUT_REG_NOTE_KIND (r, kind);
 101     }
 102   else
 103     r = gen_rtx_EXPR_LIST (kind, val, next);
 104
 105   return r;
 106 }
 107
 108 /* This function will free up an entire list of EXPR_LIST nodes.  */
 109 void
 110 free_EXPR_LIST_list (rtx *listp)
 111 {
 112   if (*listp == 0)
 113     return;
 114   free_list (listp, &unused_expr_list);
 115 }
 116
 117 /* This function will free up an entire list of INSN_LIST nodes.  */
 118 void
 119 free_INSN_LIST_list (rtx *listp)
 120 {
 121   if (*listp == 0)
 122     return;
 123   free_list (listp, &unused_insn_list);
 124 }
 125
 126 /* This function will free up an individual EXPR_LIST node.  */
 127 void
 128 free_EXPR_LIST_node (rtx ptr)
 129 {
 130   XEXP (ptr, 1) = unused_expr_list;
 131   unused_expr_list = ptr;
 132 }
 133
 134 /* This function will free up an individual INSN_LIST node.  */
 135 void
 136 free_INSN_LIST_node (rtx ptr)
 137 {
 138   XEXP (ptr, 1) = unused_insn_list;
 139   unused_insn_list = ptr;
 140 }
 141
 142 #include "gt-lists.h"