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, 2002, 2003 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
   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 GCC 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 GCC; 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 "coretypes.h"
  27 #include "tm.h"
  28 #include "rtl.h"
  29 #include "tree.h"
  30 #include "flags.h"
  31 #include "expr.h"
  32 #include "cp-tree.h"
  33 #include "toplev.h"
  34 #include "except.h"
  35 #include "tm_p.h"
  36
  37 /* Hook used by output_constant to expand language-specific
  38    constants.  */
  39
  40 tree
  41 cplus_expand_constant (cst)
  42      tree cst;
  43 {
  44   switch (TREE_CODE (cst))
  45     {
  46     case PTRMEM_CST:
  47       {
  48         tree type = TREE_TYPE (cst);
  49         tree member;
  50
  51         /* Find the member.  */
  52         member = PTRMEM_CST_MEMBER (cst);
  53
  54         if (TREE_CODE (member) == FIELD_DECL)
  55           {
  56             /* Find the offset for the field.  */
  57             tree offset = byte_position (member);
  58             cst = fold (build1 (NOP_EXPR, type, offset));
  59           }
  60         else
  61           {
  62             tree delta;
  63             tree pfn;
  64
  65             expand_ptrmemfunc_cst (cst, &delta, &pfn);
  66             cst = build_ptrmemfunc1 (type, delta, pfn);
  67           }
  68       }
  69       break;
  70
  71     default:
  72       /* There's nothing to do.  */
  73       break;
  74     }
  75
  76   return cst;
  77 }
  78
  79 /* Hook used by expand_expr to expand language-specific tree codes.  */
  80
  81 rtx
  82 cxx_expand_expr (exp, target, tmode, modifier)
  83      tree exp;
  84      rtx target;
  85      enum machine_mode tmode;
  86      int modifier;  /* Actually an enum expand_modifier.  */
  87 {
  88   tree type = TREE_TYPE (exp);
  89   register enum machine_mode mode = TYPE_MODE (type);
  90   register enum tree_code code = TREE_CODE (exp);
  91   rtx ret;
  92
  93   /* No sense saving up arithmetic to be done
  94      if it's all in the wrong mode to form part of an address.
  95      And force_operand won't know whether to sign-extend or zero-extend.  */
  96
  97   if (mode != Pmode && modifier == EXPAND_SUM)
  98     modifier = EXPAND_NORMAL;
  99
 100   switch (code)
 101     {
 102     case PTRMEM_CST:
 103       return expand_expr (cplus_expand_constant (exp),
 104                           target, tmode, modifier);
 105
 106     case OFFSET_REF:
 107       /* Offset refs should not make it through to here.  */
 108       abort ();
 109       return const0_rtx;
 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     case BASELINK:
 126       return expand_expr (BASELINK_FUNCTIONS (exp), target, tmode,
 127                           modifier);
 128
 129     default:
 130       return c_expand_expr (exp, target, tmode, modifier);
 131     }
 132   abort ();
 133   /* NOTREACHED */
 134   return NULL;
 135 }