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, 2007, 2010 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 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   /* A serial number for a sequence of frags having at most one alignment
  72      or org frag, and that at the tail of the sequence.  */
  73   unsigned int region:16;
  74
  75   /* Flipped each relax pass so we can easily determine whether
  76      fr_address has been adjusted.  */
  77   unsigned int relax_marker:1;
  78
  79   /* Used to ensure that all insns are emitted on proper address
  80      boundaries.  */
  81   unsigned int has_code:1;
  82   unsigned int insn_addr:6;
  83
  84   /* What state is my tail in? */
  85   relax_stateT fr_type;
  86   relax_substateT fr_subtype;
  87
  88 #ifdef USING_CGEN
  89   /* Don't include this unless using CGEN to keep frag size down.  */
  90   struct {
  91     /* CGEN_INSN entry for this instruction.  */
  92     const struct cgen_insn *insn;
  93     /* Index into operand table.  */
  94     int opindex;
  95     /* Target specific data, usually reloc number.  */
  96     int opinfo;
  97   } fr_cgen;
  98 #endif
  99
 100 #ifdef TC_FRAG_TYPE
 101   TC_FRAG_TYPE tc_frag_data;
 102 #endif
 103
 104   /* Data begins here.  */
 105   char fr_literal[1];
 106 };
 107
 108 #define SIZEOF_STRUCT_FRAG \
 109 ((char *) zero_address_frag.fr_literal - (char *) &zero_address_frag)
 110 /* We want to say fr_literal[0] above.  */
 111
 112 /* Current frag we are building.  This frag is incomplete.  It is,
 113    however, included in frchain_now.  The fr_fix field is bogus;
 114    instead, use frag_now_fix ().  */
 115 COMMON fragS *frag_now;
 116 extern addressT frag_now_fix (void);
 117 extern addressT frag_now_fix_octets (void);
 118
 119 /* For foreign-segment symbol fixups.  */
 120 COMMON fragS zero_address_frag;
 121 /* For local common (N_BSS segment) fixups.  */
 122 COMMON fragS bss_address_frag;
 123
 124 extern void frag_append_1_char (int);
 125 #define FRAG_APPEND_1_CHAR(X) frag_append_1_char (X)
 126
 127 void frag_init (void);
 128 fragS *frag_alloc (struct obstack *);
 129 void frag_grow (unsigned int nchars);
 130 char *frag_more (int nchars);
 131 void frag_align (int alignment, int fill_character, int max);
 132 void frag_align_pattern (int alignment, const char *fill_pattern,
 133                          int n_fill, int max);
 134 void frag_align_code (int alignment, int max);
 135 void frag_new (int old_frags_var_max_size);
 136 void frag_wane (fragS * fragP);
 137 int frag_room (void);
 138
 139 char *frag_variant (relax_stateT type,
 140                     int max_chars,
 141                     int var,
 142                     relax_substateT subtype,
 143                     symbolS * symbol,
 144                     offsetT offset,
 145                     char *opcode);
 146
 147 char *frag_var (relax_stateT type,
 148                 int max_chars,
 149                 int var,
 150                 relax_substateT subtype,
 151                 symbolS * symbol,
 152                 offsetT offset,
 153                 char *opcode);
 154
 155 bfd_boolean frag_offset_fixed_p (const fragS *, const fragS *, bfd_vma *);
 156
 157 #endif /* FRAGS_H */