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, 2004, 2007 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 3, 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 COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22
  23 #include "config.h"
  24 #include "system.h"
  25 #include "coretypes.h"
  26 #include "tm.h"
  27 #include "rtl.h"
  28 #include "tree.h"
  29 #include "flags.h"
  30 #include "expr.h"
  31 #include "cp-tree.h"
  32 #include "toplev.h"
  33 #include "except.h"
  34 #include "tm_p.h"
  35
  36 /* Expand C++-specific constants.  Currently, this means PTRMEM_CST.  */
  37
  38 tree
  39 cplus_expand_constant (tree cst)
  40 {
  41   switch (TREE_CODE (cst))
  42     {
  43     case PTRMEM_CST:
  44       {
  45         tree type = TREE_TYPE (cst);
  46         tree member;
  47
  48         /* Find the member.  */
  49         member = PTRMEM_CST_MEMBER (cst);
  50
  51         if (TREE_CODE (member) == FIELD_DECL)
  52           {
  53             /* Find the offset for the field.  */
  54             cst = byte_position (member);
  55             while (!same_type_p (DECL_CONTEXT (member),
  56                                  TYPE_PTRMEM_CLASS_TYPE (type)))
  57               {
  58                 /* The MEMBER must have been nestled within an
  59                    anonymous aggregate contained in TYPE.  Find the
  60                    anonymous aggregate.  */
  61                 member = lookup_anon_field (TYPE_PTRMEM_CLASS_TYPE (type),
  62                                             DECL_CONTEXT (member));
  63                 cst = size_binop (PLUS_EXPR, cst, byte_position (member));
  64               }
  65             cst = fold (build_nop (type, cst));
  66           }
  67         else
  68           {
  69             tree delta;
  70             tree pfn;
  71
  72             expand_ptrmemfunc_cst (cst, &delta, &pfn);
  73             cst = build_ptrmemfunc1 (type, delta, pfn);
  74           }
  75       }
  76       break;
  77
  78     default:
  79       /* There's nothing to do.  */
  80       break;
  81     }
  82
  83   return cst;
  84 }
  85
  86 /* Hook used by expand_expr to expand language-specific tree codes.  */
  87 /* ??? The only thing that should be here are things needed to expand
  88    constant initializers; everything else should be handled by the
  89    gimplification routines.  Are EMPTY_CLASS_EXPR or BASELINK needed?  */
  90
  91 rtx
  92 cxx_expand_expr (tree exp, rtx target, enum machine_mode tmode, int modifier,
  93                  rtx *alt_rtl)
  94 {
  95   tree type = TREE_TYPE (exp);
  96   enum machine_mode mode = TYPE_MODE (type);
  97   enum tree_code code = TREE_CODE (exp);
  98
  99   /* No sense saving up arithmetic to be done
 100      if it's all in the wrong mode to form part of an address.
 101      And force_operand won't know whether to sign-extend or zero-extend.  */
 102
 103   if (mode != Pmode && modifier == EXPAND_SUM)
 104     modifier = EXPAND_NORMAL;
 105
 106   switch (code)
 107     {
 108     case PTRMEM_CST:
 109       return expand_expr (cplus_expand_constant (exp),
 110                           target, tmode, modifier);
 111
 112     case OFFSET_REF:
 113       /* Offset refs should not make it through to here.  */
 114       gcc_unreachable ();
 115
 116     case EMPTY_CLASS_EXPR:
 117       /* We don't need to generate any code for an empty class.  */
 118       return const0_rtx;
 119
 120     case BASELINK:
 121       return expand_expr (BASELINK_FUNCTIONS (exp), target, tmode,
 122                           modifier);
 123
 124     default:
 125       return c_expand_expr (exp, target, tmode, modifier, alt_rtl);
 126     }
 127 }