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    2002, 2003, 2004, 2005, 2006 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, 51 Franklin Street - Fifth Floor, Boston, MA
  20    02110-1301, USA.  */
  21
  22 #ifndef FRAGS_H
  23 #define FRAGS_H
  24
  25 struct obstack;
  26
  27 /* A code fragment (frag) is some known number of chars, followed by some
  28    unknown number of chars. Typically the unknown number of chars is an
  29    instruction address whose size is yet unknown. We always know the greatest
  30    possible size the unknown number of chars may become, and reserve that
  31    much room at the end of the frag.
  32    Once created, frags do not change address during assembly.
  33    We chain the frags in (a) forward-linked list(s). The object-file address
  34    of the 1st char of a frag is generally not known until after relax().
  35    Many things at assembly time describe an address by {object-file-address
  36    of a particular frag}+offset.
  37
  38    BUG: it may be smarter to have a single pointer off to various different
  39    notes for different frag kinds.  See how code pans.  */
  40
  41 struct frag {
  42   /* Object file address (as an octet offset).  */
  43   addressT fr_address;
  44   /* When relaxing multiple times, remember the address the frag had
  45      in the last relax pass.  */
  46   addressT last_fr_address;
  47
  48   /* (Fixed) number of octets we know we have.  May be 0.  */
  49   offsetT fr_fix;
  50   /* May be used for (Variable) number of octets after above.
  51      The generic frag handling code no longer makes any use of fr_var.  */
  52   offsetT fr_var;
  53   /* For variable-length tail.  */
  54   offsetT fr_offset;
  55   /* For variable-length tail.  */
  56   symbolS *fr_symbol;
  57   /* Points to opcode low addr byte, for relaxation.  */
  58   char *fr_opcode;
  59
  60   /* Chain forward; ascending address order.  Rooted in frch_root.  */
  61   struct frag *fr_next;
  62
  63   /* Where the frag was created, or where it became a variant frag.  */
  64   char *fr_file;
  65   unsigned int fr_line;
  66
  67 #ifndef NO_LISTING
  68   struct list_info_struct *line;
  69 #endif
  70
  71   /* Flipped each relax pass so we can easily determine whether
  72      fr_address has been adjusted.  */
  73   unsigned int relax_marker:1;
  74
  75   /* Used to ensure that all insns are emitted on proper address
  76      boundaries.  */
  77   unsigned int has_code:1;
  78   unsigned int insn_addr:6;
  79
  80   /* What state is my tail in? */
  81   relax_stateT fr_type;
  82   relax_substateT fr_subtype;
  83
  84 #ifdef USING_CGEN
  85   /* Don't include this unless using CGEN to keep frag size down.  */
  86   struct {
  87     /* CGEN_INSN entry for this instruction.  */
  88     const struct cgen_insn *insn;
  89     /* Index into operand table.  */
  90     int opindex;
  91     /* Target specific data, usually reloc number.  */
  92     int opinfo;
  93   } fr_cgen;
  94 #endif
  95
  96 #ifdef TC_FRAG_TYPE
  97   TC_FRAG_TYPE tc_frag_data;
  98 #endif
  99
 100   /* Data begins here.  */
 101   char fr_literal[1];
 102 };
 103
 104 #define SIZEOF_STRUCT_FRAG \
 105 ((char *) zero_address_frag.fr_literal - (char *) &zero_address_frag)
 106 /* We want to say fr_literal[0] above.  */
 107
 108 /* Current frag we are building.  This frag is incomplete.  It is,
 109    however, included in frchain_now.  The fr_fix field is bogus;
 110    instead, use frag_now_fix ().  */
 111 COMMON fragS *frag_now;
 112 extern addressT frag_now_fix (void);
 113 extern addressT frag_now_fix_octets (void);
 114
 115 /* For foreign-segment symbol fixups.  */
 116 COMMON fragS zero_address_frag;
 117 /* For local common (N_BSS segment) fixups.  */
 118 COMMON fragS bss_address_frag;
 119
 120 extern void frag_append_1_char (int);
 121 #define FRAG_APPEND_1_CHAR(X) frag_append_1_char (X)
 122
 123 void frag_init (void);
 124 fragS *frag_alloc (struct obstack *);
 125 void frag_grow (unsigned int nchars);
 126 char *frag_more (int nchars);
 127 void frag_align (int alignment, int fill_character, int max);
 128 void frag_align_pattern (int alignment, const char *fill_pattern,
 129                          int n_fill, int max);
 130 void frag_align_code (int alignment, int max);
 131 void frag_new (int old_frags_var_max_size);
 132 void frag_wane (fragS * fragP);
 133 int frag_room (void);
 134
 135 char *frag_variant (relax_stateT type,
 136                     int max_chars,
 137                     int var,
 138                     relax_substateT subtype,
 139                     symbolS * symbol,
 140                     offsetT offset,
 141                     char *opcode);
 142
 143 char *frag_var (relax_stateT type,
 144                 int max_chars,
 145                 int var,
 146                 relax_substateT subtype,
 147                 symbolS * symbol,
 148                 offsetT offset,
 149                 char *opcode);
 150
 151 bfd_boolean frag_offset_fixed_p (const fragS *, const fragS *, bfd_vma *);
 152
 153 #endif /* FRAGS_H */