1 /* subsegs.c - subsegments -
2 Copyright (C) 1987-2021 Free Software Foundation, Inc.
4 This file is part of GAS, the GNU Assembler.
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)
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.
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
21 /* Segments & sub-segments. */
28 frchainS
*frchain_now
;
30 static struct obstack frchains
;
32 static fragS dummy_frag
;
38 obstack_begin (&frchains
, chunksize
);
40 obstack_alignment_mask (&frchains
) = __alignof__ (frchainS
) - 1;
43 frchain_now
= NULL
; /* Warn new_subseg() that we are booting. */
44 frag_now
= &dummy_frag
;
50 * Change the subsegment we are in, BUT DO NOT MAKE A NEW FRAG for the
51 * subsegment. If we are already in the correct subsegment, change nothing.
52 * This is used eg as a worker for subseg_set [which does make a new frag_now]
53 * and for changing segments after we have read the source. We construct eg
54 * fixSs even after the source file is read, so we do have to keep the
55 * segment context correct.
58 subseg_change (segT seg
, int subseg
)
60 segment_info_type
*seginfo
= seg_info (seg
);
66 seginfo
= XCNEW (segment_info_type
);
67 seginfo
->bfd_section
= seg
;
68 bfd_set_section_userdata (seg
, seginfo
);
73 subseg_set_rest (segT seg
, subsegT subseg
)
75 frchainS
*frcP
; /* crawl frchain chain */
76 frchainS
**lastPP
; /* address of last pointer */
77 frchainS
*newP
; /* address of new frchain */
78 segment_info_type
*seginfo
;
80 mri_common_symbol
= NULL
;
82 if (frag_now
&& frchain_now
)
83 frchain_now
->frch_frag_now
= frag_now
;
85 gas_assert (frchain_now
== 0
86 || frchain_now
->frch_last
== frag_now
);
88 subseg_change (seg
, (int) subseg
);
90 seginfo
= seg_info (seg
);
92 /* Should the section symbol be kept? */
93 if (bfd_keep_unused_section_symbols (stdoutput
))
94 seg
->symbol
->flags
|= BSF_SECTION_SYM_USED
;
96 /* Attempt to find or make a frchain for that subsection.
97 We keep the list sorted by subsection number. */
98 for (frcP
= *(lastPP
= &seginfo
->frchainP
);
100 frcP
= *(lastPP
= &frcP
->frch_next
))
101 if (frcP
->frch_subseg
>= subseg
)
104 if (frcP
== NULL
|| frcP
->frch_subseg
!= subseg
)
106 /* This should be the only code that creates a frchainS. */
108 newP
= (frchainS
*) obstack_alloc (&frchains
, sizeof (frchainS
));
109 newP
->frch_subseg
= subseg
;
110 newP
->fix_root
= NULL
;
111 newP
->fix_tail
= NULL
;
112 obstack_begin (&newP
->frch_obstack
, chunksize
);
114 obstack_alignment_mask (&newP
->frch_obstack
) = __alignof__ (fragS
) - 1;
116 newP
->frch_frag_now
= frag_alloc (&newP
->frch_obstack
);
117 newP
->frch_frag_now
->fr_type
= rs_fill
;
118 newP
->frch_cfi_data
= NULL
;
120 newP
->frch_root
= newP
->frch_last
= newP
->frch_frag_now
;
123 newP
->frch_next
= frcP
;
128 frag_now
= frcP
->frch_frag_now
;
130 gas_assert (frchain_now
->frch_last
== frag_now
);
134 * subseg_set(segT, subsegT)
136 * If you attempt to change to the current subsegment, nothing happens.
138 * In: segT, subsegT code for new subsegment.
139 * frag_now -> incomplete frag for current subsegment.
140 * If frag_now==NULL, then there is no old, incomplete frag, so
141 * the old frag is not closed off.
143 * Out: now_subseg, now_seg updated.
144 * Frchain_now points to the (possibly new) struct frchain for this
149 subseg_get (const char *segname
, int force_new
)
152 segment_info_type
*seginfo
;
153 const char *now_seg_name
= now_seg
? bfd_section_name (now_seg
) : 0;
157 && (now_seg_name
== segname
158 || !strcmp (now_seg_name
, segname
)))
162 secptr
= bfd_make_section_old_way (stdoutput
, segname
);
164 secptr
= bfd_make_section_anyway (stdoutput
, segname
);
166 seginfo
= seg_info (secptr
);
169 secptr
->output_section
= secptr
;
170 seginfo
= XCNEW (segment_info_type
);
171 seginfo
->bfd_section
= secptr
;
172 bfd_set_section_userdata (secptr
, seginfo
);
178 subseg_new (const char *segname
, subsegT subseg
)
182 secptr
= subseg_get (segname
, 0);
183 subseg_set_rest (secptr
, subseg
);
187 /* Like subseg_new, except a new section is always created, even if
188 a section with that name already exists. */
190 subseg_force_new (const char *segname
, subsegT subseg
)
194 secptr
= subseg_get (segname
, 1);
195 subseg_set_rest (secptr
, subseg
);
200 subseg_set (segT secptr
, subsegT subseg
)
202 if (! (secptr
== now_seg
&& subseg
== now_subseg
))
203 subseg_set_rest (secptr
, subseg
);
204 mri_common_symbol
= NULL
;
207 #ifndef obj_sec_sym_ok_for_reloc
208 #define obj_sec_sym_ok_for_reloc(SEC) 0
212 section_symbol (segT sec
)
214 segment_info_type
*seginfo
= seg_info (sec
);
222 #ifndef EMIT_SECTION_SYMBOLS
223 #define EMIT_SECTION_SYMBOLS 1
226 if (! EMIT_SECTION_SYMBOLS
|| symbol_table_frozen
)
228 /* Here we know it won't be going into the symbol table. */
229 s
= symbol_create (sec
->symbol
->name
, sec
, &zero_address_frag
, 0);
234 s
= symbol_find (sec
->symbol
->name
);
235 /* We have to make sure it is the right symbol when we
236 have multiple sections with the same section name. */
238 || ((seg
= S_GET_SEGMENT (s
)) != sec
239 && seg
!= undefined_section
))
240 s
= symbol_new (sec
->symbol
->name
, sec
, &zero_address_frag
, 0);
241 else if (seg
== undefined_section
)
243 S_SET_SEGMENT (s
, sec
);
244 symbol_set_frag (s
, &zero_address_frag
);
248 S_CLEAR_EXTERNAL (s
);
250 /* Use the BFD section symbol, if possible. */
251 if (obj_sec_sym_ok_for_reloc (sec
))
252 symbol_set_bfdsym (s
, sec
->symbol
);
254 symbol_get_bfdsym (s
)->flags
|= BSF_SECTION_SYM
;
260 /* Return whether the specified segment is thought to hold text. */
263 subseg_text_p (segT sec
)
265 return (bfd_section_flags (sec
) & SEC_CODE
) != 0;
268 /* Return non zero if SEC has at least one byte of data. It is
269 possible that we'll return zero even on a non-empty section because
270 we don't know all the fragment types, and it is possible that an
271 fr_fix == 0 one still contributes data. Think of this as
272 seg_definitely_not_empty_p. */
275 seg_not_empty_p (segT sec ATTRIBUTE_UNUSED
)
277 segment_info_type
*seginfo
= seg_info (sec
);
284 for (chain
= seginfo
->frchainP
; chain
; chain
= chain
->frch_next
)
286 for (frag
= chain
->frch_root
; frag
; frag
= frag
->fr_next
)
289 if (obstack_next_free (&chain
->frch_obstack
)
290 != chain
->frch_last
->fr_literal
)
297 subsegs_print_statistics (FILE *file
)
302 /* PR 20897 - check to see if the output bfd was actually created. */
303 if (stdoutput
== NULL
)
306 fprintf (file
, "frag chains:\n");
307 for (s
= stdoutput
->sections
; s
; s
= s
->next
)
309 segment_info_type
*seginfo
;
311 /* Skip gas-internal sections. */
312 if (segment_name (s
)[0] == '*')
315 seginfo
= seg_info (s
);
319 for (frchp
= seginfo
->frchainP
; frchp
; frchp
= frchp
->frch_next
)
324 for (fragp
= frchp
->frch_root
; fragp
; fragp
= fragp
->fr_next
)
327 fprintf (file
, "\n");
328 fprintf (file
, "\t%p %-10s\t%10d frags\n", (void *) frchp
,
329 segment_name (s
), count
);
334 /* end of subsegs.c */