1/* subsegs.h -> subsegs.c
2   Copyright (C) 1987-2017 Free Software Foundation, Inc.
3
4   This file is part of GAS, the GNU Assembler.
5
6   GAS is free software; you can redistribute it and/or modify
7   it under the terms of the GNU General Public License as published by
8   the Free Software Foundation; either version 3, or (at your option)
9   any later version.
10
11   GAS is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   GNU General Public License for more details.
15
16   You should have received a copy of the GNU General Public License
17   along with GAS; see the file COPYING.  If not, write to the Free
18   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
19   02110-1301, USA.  */
20
21/*
22 * For every sub-segment the user mentions in the ASsembler program,
23 * we make one struct frchain. Each sub-segment has exactly one struct frchain
24 * and vice versa.
25 *
26 * Struct frchain's are forward chained (in ascending order of sub-segment
27 * code number). The chain runs through frch_next of each subsegment.
28 * This makes it hard to find a subsegment's frags
29 * if programmer uses a lot of them. Most programs only use text0 and
30 * data0, so they don't suffer. At least this way:
31 * (1)	There are no "arbitrary" restrictions on how many subsegments
32 *	can be programmed;
33 * (2)	Subsegments' frchain-s are (later) chained together in the order in
34 *	which they are emitted for object file viz text then data.
35 *
36 * From each struct frchain dangles a chain of struct frags. The frags
37 * represent code fragments, for that sub-segment, forward chained.
38 */
39
40#include "obstack.h"
41
42struct frch_cfi_data;
43
44struct frchain			/* control building of a frag chain */
45{				/* FRCH = FRagment CHain control */
46  struct frag *frch_root;	/* 1st struct frag in chain, or NULL */
47  struct frag *frch_last;	/* last struct frag in chain, or NULL */
48  struct frchain *frch_next;	/* next in chain of struct frchain-s */
49  subsegT frch_subseg;		/* subsegment number of this chain */
50  fixS *fix_root;		/* Root of fixups for this subsegment.  */
51  fixS *fix_tail;		/* Last fixup for this subsegment.  */
52  struct obstack frch_obstack;	/* for objects in this frag chain */
53  fragS *frch_frag_now;		/* frag_now for this subsegment */
54  struct frch_cfi_data *frch_cfi_data;
55};
56
57typedef struct frchain frchainS;
58
59/* Frchain we are assembling into now.  That is, the current segment's
60   frag chain, even if it contains no (complete) frags.  */
61extern frchainS *frchain_now;
62
63typedef struct segment_info_struct {
64  frchainS *frchainP;
65  unsigned int hadone : 1;
66
67  /* This field is set if this is a .bss section which does not really
68     have any contents.  Once upon a time a .bss section did not have
69     any frags, but that is no longer true.  This field prevent the
70     SEC_HAS_CONTENTS flag from being set for the section even if
71     there are frags.  */
72  unsigned int bss : 1;
73
74  int user_stuff;
75
76  /* Fixups for this segment.  This is only valid after the frchains
77     are run together.  */
78  fixS *fix_root;
79  fixS *fix_tail;
80
81  symbolS *dot;
82
83  struct lineno_list *lineno_list_head;
84  struct lineno_list *lineno_list_tail;
85
86  /* Which BFD section does this gas segment correspond to?  */
87  asection *bfd_section;
88
89  /* NULL, or pointer to the gas symbol that is the section symbol for
90     this section.  sym->bsym and bfd_section->symbol should be the same.  */
91  symbolS *sym;
92
93  /* Used by dwarf2dbg.c for this section's line table entries.  */
94  void *dwarf2_line_seg;
95
96  union {
97    /* Current size of section holding stabs strings.  */
98    unsigned long stab_string_size;
99    /* Initial frag for ELF.  */
100    char *p;
101  }
102  stabu;
103
104#ifdef NEED_LITERAL_POOL
105  unsigned long literal_pool_size;
106#endif
107
108#ifdef TC_SEGMENT_INFO_TYPE
109  TC_SEGMENT_INFO_TYPE tc_segment_info_data;
110#endif
111} segment_info_type;
112
113
114#define seg_info(sec) \
115  ((segment_info_type *) bfd_get_section_userdata (stdoutput, sec))
116
117extern symbolS *section_symbol (segT);
118
119extern void subsegs_print_statistics (FILE *);
120