gas/frags.h

   1 /* frags.h - Header file for the frag concept.
   2    Copyright 1987, 1992, 1993, 1994, 1995, 1997, 1998, 1999, 2000, 2001
   3    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 2, 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, 59 Temple Place - Suite 330, Boston, MA
  20    02111-1307, USA.  */
  21
  22 #ifndef FRAGS_H
  23 #define FRAGS_H
  24
  25 #ifdef ANSI_PROTOTYPES
  26 struct obstack;
  27 #endif
  28
  29 /* A code fragment (frag) is some known number of chars, followed by some
  30    unknown number of chars. Typically the unknown number of chars is an
  31    instruction address whose size is yet unknown. We always know the greatest
  32    possible size the unknown number of chars may become, and reserve that
  33    much room at the end of the frag.
  34    Once created, frags do not change address during assembly.
  35    We chain the frags in (a) forward-linked list(s). The object-file address
  36    of the 1st char of a frag is generally not known until after relax().
  37    Many things at assembly time describe an address by {object-file-address
  38    of a particular frag}+offset.
  39
  40    BUG: it may be smarter to have a single pointer off to various different
  41    notes for different frag kinds.  See how code pans.  */
  42
  43 struct frag {
  44   /* Object file address (as an octet offset).  */
  45   addressT fr_address;
  46   /* When relaxing multiple times, remember the address the frag had
  47      in the last relax pass.  */
  48   addressT last_fr_address;
  49
  50   /* (Fixed) number of octets we know we have.  May be 0.  */
  51   offsetT fr_fix;
  52   /* May be used for (Variable) number of octets after above.
  53      The generic frag handling code no longer makes any use of fr_var.  */
  54   offsetT fr_var;
  55   /* For variable-length tail.  */
  56   offsetT fr_offset;
  57   /* For variable-length tail.  */
  58   symbolS *fr_symbol;
  59   /* Points to opcode low addr byte, for relaxation.  */
  60   char *fr_opcode;
  61
  62   /* Chain forward; ascending address order.  Rooted in frch_root.  */
  63   struct frag *fr_next;
  64
  65   /* Where the frag was created, or where it became a variant frag.  */
  66   char *fr_file;
  67   unsigned int fr_line;
  68
  69 #ifndef NO_LISTING
  70   struct list_info_struct *line;
  71 #endif
  72
  73   /* Flipped each relax pass so we can easily determine whether
  74      fr_address has been adjusted.  */
  75   unsigned int relax_marker:1;
  76
  77   /* What state is my tail in? */
  78   relax_stateT fr_type;
  79   relax_substateT fr_subtype;
  80
  81 #ifdef USING_CGEN
  82   /* Don't include this unless using CGEN to keep frag size down.  */
  83   struct {
  84     /* CGEN_INSN entry for this instruction.  */
  85     const struct cgen_insn *insn;
  86     /* Index into operand table.  */
  87     int opindex;
  88     /* Target specific data, usually reloc number.  */
  89     int opinfo;
  90   } fr_cgen;
  91 #endif
  92
  93 #ifdef TC_FRAG_TYPE
  94   TC_FRAG_TYPE tc_frag_data;
  95 #endif
  96
  97   /* Data begins here.  */
  98   char fr_literal[1];
  99 };
 100
 101 #define SIZEOF_STRUCT_FRAG \
 102 ((char *) zero_address_frag.fr_literal - (char *) &zero_address_frag)
 103 /* We want to say fr_literal[0] above.  */
 104
 105 /* Current frag we are building.  This frag is incomplete.  It is,
 106    however, included in frchain_now.  The fr_fix field is bogus;
 107    instead, use frag_now_fix ().  */
 108 COMMON fragS *frag_now;
 109 extern addressT frag_now_fix (void);
 110 extern addressT frag_now_fix_octets (void);
 111
 112 /* For foreign-segment symbol fixups.  */
 113 COMMON fragS zero_address_frag;
 114 /* For local common (N_BSS segment) fixups.  */
 115 COMMON fragS bss_address_frag;
 116
 117 #if 0
 118 /* A macro to speed up appending exactly 1 char to current frag.  */
 119 /* JF changed < 1 to <= 1 to avoid a race condition.  */
 120 #define FRAG_APPEND_1_CHAR(datum)                       \
 121 {                                                       \
 122   if (obstack_room (&frags) <= 1)                       \
 123     {                                                   \
 124       frag_wane (frag_now);                             \
 125       frag_new (0);                                     \
 126     }                                                   \
 127   obstack_1grow (&frags, datum);                        \
 128 }
 129 #else
 130 extern void frag_append_1_char (int);
 131 #define FRAG_APPEND_1_CHAR(X) frag_append_1_char (X)
 132 #endif
 133
 134 void frag_init (void);
 135 fragS *frag_alloc (struct obstack *);
 136 void frag_grow (unsigned int nchars);
 137 char *frag_more (int nchars);
 138 void frag_align (int alignment, int fill_character, int max);
 139 void frag_align_pattern (int alignment, const char *fill_pattern,
 140                          int n_fill, int max);
 141 void frag_align_code (int alignment, int max);
 142 void frag_new (int old_frags_var_max_size);
 143 void frag_wane (fragS * fragP);
 144 int frag_room (void);
 145
 146 char *frag_variant (relax_stateT type,
 147                     int max_chars,
 148                     int var,
 149                     relax_substateT subtype,
 150                     symbolS * symbol,
 151                     offsetT offset,
 152                     char *opcode);
 153
 154 char *frag_var (relax_stateT type,
 155                 int max_chars,
 156                 int var,
 157                 relax_substateT subtype,
 158                 symbolS * symbol,
 159                 offsetT offset,
 160                 char *opcode);
 161
 162 #endif /* FRAGS_H */