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 /* Hook used by output_constant to expand language-specific
  36    constants.  */
  37
  38 tree
  39 cplus_expand_constant (cst)
  40      tree cst;
  41 {
  42   switch (TREE_CODE (cst))
  43     {
  44     case PTRMEM_CST:
  45       {
  46         tree type = TREE_TYPE (cst);
  47         tree member;
  48
  49         /* Find the member.  */
  50         member = PTRMEM_CST_MEMBER (cst);
  51
  52         if (TREE_CODE (member) == FIELD_DECL)
  53           {
  54             /* Find the offset for the field.  */
  55             tree offset = byte_position (member);
  56             cst = fold (build1 (NOP_EXPR, type, offset));
  57           }
  58         else
  59           {
  60             tree delta;
  61             tree pfn;
  62
  63             expand_ptrmemfunc_cst (cst, &delta, &pfn);
  64             cst = build_ptrmemfunc1 (type, delta, pfn);
  65           }
  66       }
  67       break;
  68
  69     default:
  70       /* There's nothing to do.  */
  71       break;
  72     }
  73
  74   return cst;
  75 }
  76
  77 /* Hook used by expand_expr to expand language-specific tree codes.  */
  78
  79 rtx
  80 cxx_expand_expr (exp, target, tmode, modifier)
  81      tree exp;
  82      rtx target;
  83      enum machine_mode tmode;
  84      int modifier;  /* Actually an enum expand_modifier.  */
  85 {
  86   tree type = TREE_TYPE (exp);
  87   register enum machine_mode mode = TYPE_MODE (type);
  88   register enum tree_code code = TREE_CODE (exp);
  89   rtx ret;
  90
  91   /* No sense saving up arithmetic to be done
  92      if it's all in the wrong mode to form part of an address.
  93      And force_operand won't know whether to sign-extend or zero-extend.  */
  94
  95   if (mode != Pmode && modifier == EXPAND_SUM)
  96     modifier = EXPAND_NORMAL;
  97
  98   switch (code)
  99     {
 100     case PTRMEM_CST:
 101       return expand_expr (cplus_expand_constant (exp),
 102                           target, tmode, modifier);
 103
 104     case OFFSET_REF:
 105       /* Offset refs should not make it through to here.  */
 106       abort ();
 107       return const0_rtx;
 108
 109     case THROW_EXPR:
 110       expand_expr (TREE_OPERAND (exp, 0), const0_rtx, VOIDmode, 0);
 111       return NULL;
 112
 113     case MUST_NOT_THROW_EXPR:
 114       expand_eh_region_start ();
 115       ret = expand_expr (TREE_OPERAND (exp, 0), target, tmode, modifier);
 116       expand_eh_region_end_must_not_throw (build_call (terminate_node, 0));
 117       return ret;
 118
 119     case EMPTY_CLASS_EXPR:
 120       /* We don't need to generate any code for an empty class.  */
 121       return const0_rtx;
 122
 123     default:
 124       return c_expand_expr (exp, target, tmode, modifier);
 125     }
 126   abort ();
 127   /* NOTREACHED */
 128   return NULL;
 129 }