expr.c revision 90075 
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
6This file is part of GNU CC.
7
8GNU CC is free software; you can redistribute it and/or modify
9it under the terms of the GNU General Public License as published by
10the Free Software Foundation; either version 2, or (at your option)
11any later version.
12
13GNU CC is distributed in the hope that it will be useful,
14but WITHOUT ANY WARRANTY; without even the implied warranty of
15MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16GNU General Public License for more details.
17
18You should have received a copy of the GNU General Public License
19along with GNU CC; see the file COPYING.  If not, write to
20the Free Software Foundation, 59 Temple Place - Suite 330,
21Boston, 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
35static 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
41tree
42cplus_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
82static rtx
83cplus_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      /* Offset refs should not make it through to here. */
109      abort ();
110      return const0_rtx;
111
112    case THROW_EXPR:
113      expand_expr (TREE_OPERAND (exp, 0), const0_rtx, VOIDmode, 0);
114      return NULL;
115
116    case MUST_NOT_THROW_EXPR:
117      expand_eh_region_start ();
118      ret = expand_expr (TREE_OPERAND (exp, 0), target, tmode, modifier);
119      expand_eh_region_end_must_not_throw (build_call (terminate_node, 0));
120      return ret;
121
122    case EMPTY_CLASS_EXPR:
123      /* We don't need to generate any code for an empty class.  */
124      return const0_rtx;
125
126    default:
127      return c_expand_expr (exp, target, tmode, modifier);
128    }
129  abort ();
130  /* NOTREACHED */
131  return NULL;
132}
133
134void
135init_cplus_expand ()
136{
137  lang_expand_expr = cplus_expand_expr;
138}
139
140int
141extract_init (decl, init)
142     tree decl ATTRIBUTE_UNUSED, init ATTRIBUTE_UNUSED;
143{
144  return 0;
145}
146
147