binutils  2.23.2
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struc-symbol.h
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1 /* struct_symbol.h - Internal symbol structure
2  Copyright 1987, 1992, 1993, 1994, 1995, 1998, 1999, 2000, 2001, 2005,
3  2007, 2008, 2009 Free Software Foundation, Inc.
4 
5  This file is part of GAS, the GNU Assembler.
6 
7  GAS is free software; you can redistribute it and/or modify
8  it under the terms of the GNU General Public License as published by
9  the Free Software Foundation; either version 3, or (at your option)
10  any later version.
11 
12  GAS is distributed in the hope that it will be useful,
13  but WITHOUT ANY WARRANTY; without even the implied warranty of
14  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15  GNU General Public License for more details.
16 
17  You should have received a copy of the GNU General Public License
18  along with GAS; see the file COPYING. If not, write to the Free
19  Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
20  02110-1301, USA. */
21 
22 #ifndef __struc_symbol_h__
23 #define __struc_symbol_h__
24 
25 struct symbol_flags
26 {
27  /* Wether the symbol is a local_symbol. */
28  unsigned int sy_local_symbol : 1;
29 
30  /* Wether symbol has been written. */
31  unsigned int sy_written : 1;
32 
33  /* Whether symbol value has been completely resolved (used during
34  final pass over symbol table). */
35  unsigned int sy_resolved : 1;
36 
37  /* Whether the symbol value is currently being resolved (used to
38  detect loops in symbol dependencies). */
39  unsigned int sy_resolving : 1;
40 
41  /* Whether the symbol value is used in a reloc. This is used to
42  ensure that symbols used in relocs are written out, even if they
43  are local and would otherwise not be. */
44  unsigned int sy_used_in_reloc : 1;
45 
46  /* Whether the symbol is used as an operand or in an expression.
47  NOTE: Not all the backends keep this information accurate;
48  backends which use this bit are responsible for setting it when
49  a symbol is used in backend routines. */
50  unsigned int sy_used : 1;
51 
52  /* Whether the symbol can be re-defined. */
53  unsigned int sy_volatile : 1;
54 
55  /* Whether the symbol is a forward reference. */
56  unsigned int sy_forward_ref : 1;
57 
58  /* This is set if the symbol is defined in an MRI common section.
59  We handle such sections as single common symbols, so symbols
60  defined within them must be treated specially by the relocation
61  routines. */
62  unsigned int sy_mri_common : 1;
63 
64  /* This is set if the symbol is set with a .weakref directive. */
65  unsigned int sy_weakrefr : 1;
66 
67  /* This is set when the symbol is referenced as part of a .weakref
68  directive, but only if the symbol was not in the symbol table
69  before. It is cleared as soon as any direct reference to the
70  symbol is present. */
71  unsigned int sy_weakrefd : 1;
72 };
73 
74 /* The information we keep for a symbol. Note that the symbol table
75  holds pointers both to this and to local_symbol structures. See
76  below. */
77 
78 struct symbol
79 {
80  /* Symbol flags. */
81  struct symbol_flags sy_flags;
82 
83  /* BFD symbol */
84  asymbol *bsym;
85 
86  /* The value of the symbol. */
87  expressionS sy_value;
88 
89  /* Forwards and (optionally) backwards chain pointers. */
90  struct symbol *sy_next;
91  struct symbol *sy_previous;
92 
93  /* Pointer to the frag this symbol is attached to, if any.
94  Otherwise, NULL. */
95  struct frag *sy_frag;
96 
97 #ifdef OBJ_SYMFIELD_TYPE
98  OBJ_SYMFIELD_TYPE sy_obj;
99 #endif
100 
101 #ifdef TC_SYMFIELD_TYPE
102  TC_SYMFIELD_TYPE sy_tc;
103 #endif
104 
105 #ifdef TARGET_SYMBOL_FIELDS
106  TARGET_SYMBOL_FIELDS
107 #endif
108 };
109 
110 /* A pointer in the symbol may point to either a complete symbol
111  (struct symbol above) or to a local symbol (struct local_symbol
112  defined here). The symbol code can detect the case by examining
113  the first field. It is always NULL for a local symbol.
114 
115  We do this because we ordinarily only need a small amount of
116  information for a local symbol. The symbol table takes up a lot of
117  space, and storing less information for a local symbol can make a
118  big difference in assembler memory usage when assembling a large
119  file. */
120 
121 struct local_symbol
122 {
123  /* Symbol flags. Only sy_local_symbol and sy_resolved are relevant. */
124  struct symbol_flags lsy_flags;
125 
126  /* The symbol section. This also serves as a flag. If this is
127  reg_section, then this symbol has been converted into a regular
128  symbol, and lsy_sym points to it. */
129  segT lsy_section;
130 
131  /* The symbol name. */
132  const char *lsy_name;
133 
134  /* The symbol frag or the real symbol, depending upon the value in
135  lsy_section. */
136  union
137  {
138  fragS *lsy_frag;
139  symbolS *lsy_sym;
140  } u;
141 
142  /* The value of the symbol. */
143  valueT lsy_value;
144 
145 #ifdef TC_LOCAL_SYMFIELD_TYPE
146  TC_LOCAL_SYMFIELD_TYPE lsy_tc;
147 #endif
148 };
149 
150 #define local_symbol_converted_p(l) ((l)->lsy_section == reg_section)
151 #define local_symbol_mark_converted(l) ((l)->lsy_section = reg_section)
152 #define local_symbol_resolved_p(l) ((l)->lsy_flags.sy_resolved)
153 #define local_symbol_mark_resolved(l) ((l)->lsy_flags.sy_resolved = 1)
154 #define local_symbol_get_frag(l) ((l)->u.lsy_frag)
155 #define local_symbol_set_frag(l, f) ((l)->u.lsy_frag = (f))
156 #define local_symbol_get_real_symbol(l) ((l)->u.lsy_sym)
157 #define local_symbol_set_real_symbol(l, s) ((l)->u.lsy_sym = (s))
158 
159 #endif /* __struc_symbol_h__ */