gcc/cp/expr.c

   1 /* Convert language-specific tree expression to rtl instructions,
   2    for GNU compiler.
   3    Copyright (C) 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   4    2000, 2001 Free Software Foundation, Inc.
   5
   6 This file is part of GNU CC.
   7
   8 GNU CC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 2, or (at your option)
  11 any later version.
  12
  13 GNU CC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GNU CC; see the file COPYING.  If not, write to
  20 the Free Software Foundation, 59 Temple Place - Suite 330,
  21 Boston, MA 02111-1307, USA.  */
  22
  23
  24 #include "config.h"
  25 #include "system.h"
  26 #include "rtl.h"
  27 #include "tree.h"
  28 #include "flags.h"
  29 #include "expr.h"
  30 #include "cp-tree.h"
  31 #include "toplev.h"
  32 #include "except.h"
  33 #include "tm_p.h"
  34
  35 static rtx cplus_expand_expr PARAMS ((tree, rtx, enum machine_mode,
  36                                     enum expand_modifier));
  37
  38 /* Hook used by output_constant to expand language-specific
  39    constants.  */
  40
  41 tree
  42 cplus_expand_constant (cst)
  43      tree cst;
  44 {
  45   switch (TREE_CODE (cst))
  46     {
  47     case PTRMEM_CST:
  48       {
  49         tree type = TREE_TYPE (cst);
  50         tree member;
  51
  52         /* Find the member.  */
  53         member = PTRMEM_CST_MEMBER (cst);
  54
  55         if (TREE_CODE (member) == FIELD_DECL)
  56           {
  57             /* Find the offset for the field.  */
  58             tree offset = byte_position (member);
  59             cst = fold (build1 (NOP_EXPR, type, offset));
  60           }
  61         else
  62           {
  63             tree delta;
  64             tree pfn;
  65
  66             expand_ptrmemfunc_cst (cst, &delta, &pfn);
  67             cst = build_ptrmemfunc1 (type, delta, pfn);
  68           }
  69       }
  70       break;
  71
  72     default:
  73       /* There's nothing to do.  */
  74       break;
  75     }
  76
  77   return cst;
  78 }
  79
  80 /* Hook used by expand_expr to expand language-specific tree codes.  */
  81
  82 static rtx
  83 cplus_expand_expr (exp, target, tmode, modifier)
  84      tree exp;
  85      rtx target;
  86      enum machine_mode tmode;
  87      enum expand_modifier modifier;
  88 {
  89   tree type = TREE_TYPE (exp);
  90   register enum machine_mode mode = TYPE_MODE (type);
  91   register enum tree_code code = TREE_CODE (exp);
  92   rtx ret;
  93
  94   /* No sense saving up arithmetic to be done
  95      if it's all in the wrong mode to form part of an address.
  96      And force_operand won't know whether to sign-extend or zero-extend.  */
  97
  98   if (mode != Pmode && modifier == EXPAND_SUM)
  99     modifier = EXPAND_NORMAL;
 100
 101   switch (code)
 102     {
 103     case PTRMEM_CST:
 104       return expand_expr (cplus_expand_constant (exp),
 105                           target, tmode, modifier);
 106
 107     case OFFSET_REF:
 108       return expand_expr (default_conversion (resolve_offset_ref (exp)),
 109                           target, tmode, EXPAND_NORMAL);
 110
 111     case THROW_EXPR:
 112       expand_expr (TREE_OPERAND (exp, 0), const0_rtx, VOIDmode, 0);
 113       return NULL;
 114
 115     case MUST_NOT_THROW_EXPR:
 116       expand_eh_region_start ();
 117       ret = expand_expr (TREE_OPERAND (exp, 0), target, tmode, modifier);
 118       expand_eh_region_end_must_not_throw (build_call (terminate_node, 0));
 119       return ret;
 120
 121     case EMPTY_CLASS_EXPR:
 122       /* We don't need to generate any code for an empty class.  */
 123       return const0_rtx;
 124
 125     default:
 126       return c_expand_expr (exp, target, tmode, modifier);
 127     }
 128   my_friendly_abort (40);
 129   /* NOTREACHED */
 130   return NULL;
 131 }
 132
 133 void
 134 init_cplus_expand ()
 135 {
 136   lang_expand_expr = cplus_expand_expr;
 137   lang_expand_constant = cplus_expand_constant;
 138 }
 139
 140 int
 141 extract_init (decl, init)
 142      tree decl ATTRIBUTE_UNUSED, init ATTRIBUTE_UNUSED;
 143 {
 144   return 0;
 145 }
 146