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[deliverable/binutils-gdb.git] / gas / subsegs.h
1 /* subsegs.h -> subsegs.c
2 Copyright (C) 1987, 92, 93, 94, 95, 96, 1998 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 2, 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, 59 Temple Place - Suite 330, Boston, MA
19 02111-1307, 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
42 struct frchain /* control building of a frag chain */
43 { /* FRCH = FRagment CHain control */
44 struct frag *frch_root; /* 1st struct frag in chain, or NULL */
45 struct frag *frch_last; /* last struct frag in chain, or NULL */
46 struct frchain *frch_next; /* next in chain of struct frchain-s */
47 segT frch_seg; /* SEG_TEXT or SEG_DATA. */
48 subsegT frch_subseg; /* subsegment number of this chain */
49 #ifdef BFD_ASSEMBLER
50 fixS *fix_root; /* Root of fixups for this subsegment. */
51 fixS *fix_tail; /* Last fixup for this subsegment. */
52 #endif
53 struct obstack frch_obstack; /* for objects in this frag chain */
54 fragS *frch_frag_now; /* frag_now for this subsegment */
55 };
56
57 typedef struct frchain frchainS;
58
59 /* All subsegments' chains hang off here. NULL means no frchains yet. */
60 extern frchainS *frchain_root;
61
62 /* Frchain we are assembling into now. That is, the current segment's
63 frag chain, even if it contains no (complete) frags. */
64 extern frchainS *frchain_now;
65
66
67 typedef struct segment_info_struct
68 {
69 frchainS *frchainP;
70 unsigned int hadone : 1;
71
72 /* This field is set if this is a .bss section which does not really
73 have any contents. Once upon a time a .bss section did not have
74 any frags, but that is no longer true. This field prevent the
75 SEC_HAS_CONTENTS flag from being set for the section even if
76 there are frags. */
77 unsigned int bss : 1;
78
79 int user_stuff;
80
81 /* Fixups for this segment. If BFD_ASSEMBLER, this is only valid
82 after the frchains are run together. */
83 fixS *fix_root;
84 fixS *fix_tail;
85
86 #if defined (MANY_SEGMENTS) && !defined (BFD_ASSEMBLER)
87 struct internal_scnhdr scnhdr;
88 enum linkonce_type linkonce;
89 const char *name;
90 #endif
91
92 symbolS *dot;
93
94 struct lineno_list *lineno_list_head;
95 struct lineno_list *lineno_list_tail;
96
97 #ifdef BFD_ASSEMBLER
98 /* Which BFD section does this gas segment correspond to? */
99 asection *bfd_section;
100
101 /* NULL, or pointer to the gas symbol that is the section symbol for
102 this section. sym->bsym and bfd_section->symbol should be the same. */
103 symbolS *sym;
104 #endif
105
106 union
107 {
108 /* Current size of section holding stabs strings. */
109 unsigned long stab_string_size;
110 /* Initial frag for ELF. */
111 char *p;
112 }
113 stabu;
114
115 #ifdef NEED_LITERAL_POOL
116 unsigned long literal_pool_size;
117 #endif
118
119 #ifdef TC_SEGMENT_INFO_TYPE
120 TC_SEGMENT_INFO_TYPE tc_segment_info_data;
121 #endif
122 } segment_info_type;
123
124 #ifdef BFD_ASSEMBLER
125
126 extern segment_info_type *seg_info PARAMS ((segT));
127 extern symbolS *section_symbol PARAMS ((segT));
128
129 #else /* ! BFD_ASSEMBLER */
130
131 #ifdef MANY_SEGMENTS
132
133 extern segment_info_type segment_info[];
134
135 #define seg_info(SEC) (&segment_info[SEC])
136
137 #else
138
139 /* Sentinel for frchain crawling. Points to the 1st data-segment
140 frchain. (Which is pointed to by the last text-segment frchain.) */
141 extern frchainS *data0_frchainP;
142 extern frchainS *bss0_frchainP;
143
144 /* Dummy so stuff can compile. Should never be used. */
145 struct seg_info_trash {
146 struct {
147 unsigned stab_string_size : 1;
148 } stabu;
149 unsigned hadone : 1;
150 };
151 #define seg_info(S) (abort (), (struct seg_info_trash *) 0)
152
153 #endif
154
155 #endif /* ! BFD_ASSEMBLER */
156
157 extern void subsegs_print_statistics PARAMS ((FILE *));
158
159 /* end of subsegs.h */
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