1/* subsegs.h -> subsegs.c
2   Copyright 1987, 1992, 1993, 1994, 1995, 1996, 1998, 2000, 2003, 2005,
3   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/*
23 * For every sub-segment the user mentions in the ASsembler program,
24 * we make one struct frchain. Each sub-segment has exactly one struct frchain
25 * and vice versa.
26 *
27 * Struct frchain's are forward chained (in ascending order of sub-segment
28 * code number). The chain runs through frch_next of each subsegment.
29 * This makes it hard to find a subsegment's frags
30 * if programmer uses a lot of them. Most programs only use text0 and
31 * data0, so they don't suffer. At least this way:
32 * (1)	There are no "arbitrary" restrictions on how many subsegments
33 *	can be programmed;
34 * (2)	Subsegments' frchain-s are (later) chained together in the order in
35 *	which they are emitted for object file viz text then data.
36 *
37 * From each struct frchain dangles a chain of struct frags. The frags
38 * represent code fragments, for that sub-segment, forward chained.
39 */
40
41#include "obstack.h"
42
43struct frch_cfi_data;
44
45struct frchain			/* control building of a frag chain */
46{				/* FRCH = FRagment CHain control */
47  struct frag *frch_root;	/* 1st struct frag in chain, or NULL */
48  struct frag *frch_last;	/* last struct frag in chain, or NULL */
49  struct frchain *frch_next;	/* next in chain of struct frchain-s */
50  subsegT frch_subseg;		/* subsegment number of this chain */
51  fixS *fix_root;		/* Root of fixups for this subsegment.  */
52  fixS *fix_tail;		/* Last fixup for this subsegment.  */
53  struct obstack frch_obstack;	/* for objects in this frag chain */
54  fragS *frch_frag_now;		/* frag_now for this subsegment */
55  struct frch_cfi_data *frch_cfi_data;
56};
57
58typedef struct frchain frchainS;
59
60/* Frchain we are assembling into now.  That is, the current segment's
61   frag chain, even if it contains no (complete) frags.  */
62extern frchainS *frchain_now;
63
64typedef struct segment_info_struct {
65  frchainS *frchainP;
66  unsigned int hadone : 1;
67
68  /* This field is set if this is a .bss section which does not really
69     have any contents.  Once upon a time a .bss section did not have
70     any frags, but that is no longer true.  This field prevent the
71     SEC_HAS_CONTENTS flag from being set for the section even if
72     there are frags.  */
73  unsigned int bss : 1;
74
75  int user_stuff;
76
77  /* Fixups for this segment.  This is only valid after the frchains
78     are run together.  */
79  fixS *fix_root;
80  fixS *fix_tail;
81
82  symbolS *dot;
83
84  struct lineno_list *lineno_list_head;
85  struct lineno_list *lineno_list_tail;
86
87  /* Which BFD section does this gas segment correspond to?  */
88  asection *bfd_section;
89
90  /* NULL, or pointer to the gas symbol that is the section symbol for
91     this section.  sym->bsym and bfd_section->symbol should be the same.  */
92  symbolS *sym;
93
94  union {
95    /* Current size of section holding stabs strings.  */
96    unsigned long stab_string_size;
97    /* Initial frag for ELF.  */
98    char *p;
99  }
100  stabu;
101
102#ifdef NEED_LITERAL_POOL
103  unsigned long literal_pool_size;
104#endif
105
106#ifdef TC_SEGMENT_INFO_TYPE
107  TC_SEGMENT_INFO_TYPE tc_segment_info_data;
108#endif
109} segment_info_type;
110
111
112#define seg_info(sec) \
113  ((segment_info_type *) bfd_get_section_userdata (stdoutput, sec))
114
115extern symbolS *section_symbol (segT);
116
117extern void subsegs_print_statistics (FILE *);
118