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
25struct 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
41struct 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 ().  */
111COMMON fragS *frag_now;
112extern addressT frag_now_fix (void);
113extern addressT frag_now_fix_octets (void);
114
115/* For foreign-segment symbol fixups.  */
116COMMON fragS zero_address_frag;
117/* For local common (N_BSS segment) fixups.  */
118COMMON fragS bss_address_frag;
119
120extern void frag_append_1_char (int);
121#define FRAG_APPEND_1_CHAR(X) frag_append_1_char (X)
122
123void frag_init (void);
124fragS *frag_alloc (struct obstack *);
125void frag_grow (unsigned int nchars);
126char *frag_more (int nchars);
127void frag_align (int alignment, int fill_character, int max);
128void frag_align_pattern (int alignment, const char *fill_pattern,
129			 int n_fill, int max);
130void frag_align_code (int alignment, int max);
131void frag_new (int old_frags_var_max_size);
132void frag_wane (fragS * fragP);
133int frag_room (void);
134
135char *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
143char *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
151bfd_boolean frag_offset_fixed_p (const fragS *, const fragS *, bfd_vma *);
152
153#endif /* FRAGS_H */
154