gas/struc-symbol.h

   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__ */