1 /* subsegs.c - subsegments -
2 Copyright 1987, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
4 Free Software Foundation, Inc.
6 This file is part of GAS, the GNU Assembler.
8 GAS is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2, or (at your option)
13 GAS is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GAS; see the file COPYING. If not, write to the Free
20 Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
23 /* Segments & sub-segments. */
30 frchainS
*frchain_root
, *frchain_now
;
32 static struct obstack frchains
;
34 /* Gas segment information for bfd_abs_section_ptr and
35 bfd_und_section_ptr. */
36 static segment_info_type
*abs_seg_info
;
37 static segment_info_type
*und_seg_info
;
39 static void subseg_set_rest (segT
, subsegT
);
41 static fragS dummy_frag
;
43 static frchainS absolute_frchain
;
48 obstack_begin (&frchains
, chunksize
);
50 obstack_alignment_mask (&frchains
) = __alignof__ (frchainS
) - 1;
54 frchain_now
= NULL
; /* Warn new_subseg() that we are booting. */
56 frag_now
= &dummy_frag
;
58 absolute_frchain
.frch_seg
= absolute_section
;
59 absolute_frchain
.frch_subseg
= 0;
60 absolute_frchain
.fix_root
= absolute_frchain
.fix_tail
= 0;
61 absolute_frchain
.frch_frag_now
= &zero_address_frag
;
62 absolute_frchain
.frch_root
= absolute_frchain
.frch_last
= &zero_address_frag
;
68 * Change the subsegment we are in, BUT DO NOT MAKE A NEW FRAG for the
69 * subsegment. If we are already in the correct subsegment, change nothing.
70 * This is used eg as a worker for subseg_set [which does make a new frag_now]
71 * and for changing segments after we have read the source. We construct eg
72 * fixSs even after the source file is read, so we do have to keep the
73 * segment context correct.
76 subseg_change (register segT seg
, register int subseg
)
78 segment_info_type
*seginfo
;
82 if (now_seg
== absolute_section
)
85 seginfo
= (segment_info_type
*) bfd_get_section_userdata (stdoutput
, seg
);
88 seginfo
= (segment_info_type
*) xmalloc (sizeof (*seginfo
));
89 memset ((PTR
) seginfo
, 0, sizeof (*seginfo
));
90 seginfo
->fix_root
= NULL
;
91 seginfo
->fix_tail
= NULL
;
92 seginfo
->bfd_section
= seg
;
94 if (seg
== bfd_abs_section_ptr
)
95 abs_seg_info
= seginfo
;
96 else if (seg
== bfd_und_section_ptr
)
97 und_seg_info
= seginfo
;
99 bfd_set_section_userdata (stdoutput
, seg
, (PTR
) seginfo
);
104 subseg_set_rest (segT seg
, subsegT subseg
)
106 register frchainS
*frcP
; /* crawl frchain chain */
107 register frchainS
**lastPP
; /* address of last pointer */
108 frchainS
*newP
; /* address of new frchain */
110 mri_common_symbol
= NULL
;
112 if (frag_now
&& frchain_now
)
113 frchain_now
->frch_frag_now
= frag_now
;
115 assert (frchain_now
== 0
116 || now_seg
== undefined_section
117 || now_seg
== absolute_section
118 || frchain_now
->frch_last
== frag_now
);
120 subseg_change (seg
, (int) subseg
);
122 if (seg
== absolute_section
)
124 frchain_now
= &absolute_frchain
;
125 frag_now
= &zero_address_frag
;
129 assert (frchain_now
== 0
130 || now_seg
== undefined_section
131 || frchain_now
->frch_last
== frag_now
);
134 * Attempt to find or make a frchain for that sub seg.
135 * Crawl along chain of frchainSs, begins @ frchain_root.
136 * If we need to make a frchainS, link it into correct
137 * position of chain rooted in frchain_root.
139 for (frcP
= *(lastPP
= &frchain_root
);
140 frcP
&& frcP
->frch_seg
<= seg
;
141 frcP
= *(lastPP
= &frcP
->frch_next
))
143 if (frcP
->frch_seg
== seg
144 && frcP
->frch_subseg
>= subseg
)
150 * frcP: Address of the 1st frchainS in correct segment with
151 * frch_subseg >= subseg.
152 * We want to either use this frchainS, or we want
153 * to insert a new frchainS just before it.
155 * If frcP==NULL, then we are at the end of the chain
156 * of frchainS-s. A NULL frcP means we fell off the end
157 * of the chain looking for a
158 * frch_subseg >= subseg, so we
159 * must make a new frchainS.
161 * If we ever maintain a pointer to
162 * the last frchainS in the chain, we change that pointer
163 * ONLY when frcP==NULL.
165 * lastPP: Address of the pointer with value frcP;
167 * May point to frchain_root.
171 || (frcP
->frch_seg
> seg
172 || frcP
->frch_subseg
> subseg
)) /* Kinky logic only works with 2 segments. */
175 * This should be the only code that creates a frchainS.
177 segment_info_type
*seginfo
;
179 newP
= (frchainS
*) obstack_alloc (&frchains
, sizeof (frchainS
));
180 newP
->frch_subseg
= subseg
;
181 newP
->frch_seg
= seg
;
182 newP
->fix_root
= NULL
;
183 newP
->fix_tail
= NULL
;
184 obstack_begin (&newP
->frch_obstack
, chunksize
);
186 obstack_alignment_mask (&newP
->frch_obstack
) = __alignof__ (fragS
) - 1;
188 newP
->frch_frag_now
= frag_alloc (&newP
->frch_obstack
);
189 newP
->frch_frag_now
->fr_type
= rs_fill
;
191 newP
->frch_root
= newP
->frch_last
= newP
->frch_frag_now
;
194 newP
->frch_next
= frcP
; /* perhaps NULL */
196 seginfo
= seg_info (seg
);
197 if (seginfo
&& (!seginfo
->frchainP
|| seginfo
->frchainP
== frcP
))
198 seginfo
->frchainP
= newP
;
203 * Here with frcP pointing to the frchainS for subseg.
206 frag_now
= frcP
->frch_frag_now
;
208 assert (frchain_now
->frch_last
== frag_now
);
212 * subseg_set(segT, subsegT)
214 * If you attempt to change to the current subsegment, nothing happens.
216 * In: segT, subsegT code for new subsegment.
217 * frag_now -> incomplete frag for current subsegment.
218 * If frag_now==NULL, then there is no old, incomplete frag, so
219 * the old frag is not closed off.
221 * Out: now_subseg, now_seg updated.
222 * Frchain_now points to the (possibly new) struct frchain for this
224 * Frchain_root updated if needed.
228 subseg_get (const char *segname
, int force_new
)
231 segment_info_type
*seginfo
;
232 const char *now_seg_name
= (now_seg
233 ? bfd_get_section_name (stdoutput
, now_seg
)
238 && (now_seg_name
== segname
239 || !strcmp (now_seg_name
, segname
)))
243 secptr
= bfd_make_section_old_way (stdoutput
, segname
);
245 secptr
= bfd_make_section_anyway (stdoutput
, segname
);
247 seginfo
= seg_info (secptr
);
250 /* Check whether output_section is set first because secptr may
251 be bfd_abs_section_ptr. */
252 if (secptr
->output_section
!= secptr
)
253 secptr
->output_section
= secptr
;
254 seginfo
= (segment_info_type
*) xmalloc (sizeof (*seginfo
));
255 memset ((PTR
) seginfo
, 0, sizeof (*seginfo
));
256 seginfo
->fix_root
= NULL
;
257 seginfo
->fix_tail
= NULL
;
258 seginfo
->bfd_section
= secptr
;
259 if (secptr
== bfd_abs_section_ptr
)
260 abs_seg_info
= seginfo
;
261 else if (secptr
== bfd_und_section_ptr
)
262 und_seg_info
= seginfo
;
264 bfd_set_section_userdata (stdoutput
, secptr
, (PTR
) seginfo
);
265 seginfo
->frchainP
= NULL
;
266 seginfo
->lineno_list_head
= seginfo
->lineno_list_tail
= NULL
;
274 subseg_new (const char *segname
, subsegT subseg
)
277 segment_info_type
*seginfo
;
279 secptr
= subseg_get (segname
, 0);
280 subseg_set_rest (secptr
, subseg
);
281 seginfo
= seg_info (secptr
);
282 if (! seginfo
->frchainP
)
283 seginfo
->frchainP
= frchain_now
;
287 /* Like subseg_new, except a new section is always created, even if
288 a section with that name already exists. */
290 subseg_force_new (const char *segname
, subsegT subseg
)
293 segment_info_type
*seginfo
;
295 secptr
= subseg_get (segname
, 1);
296 subseg_set_rest (secptr
, subseg
);
297 seginfo
= seg_info (secptr
);
298 if (! seginfo
->frchainP
)
299 seginfo
->frchainP
= frchain_now
;
304 subseg_set (segT secptr
, subsegT subseg
)
306 if (! (secptr
== now_seg
&& subseg
== now_subseg
))
307 subseg_set_rest (secptr
, subseg
);
308 mri_common_symbol
= NULL
;
311 #ifndef obj_sec_sym_ok_for_reloc
312 #define obj_sec_sym_ok_for_reloc(SEC) 0
315 /* Get the gas information we are storing for a section. */
320 if (sec
== bfd_abs_section_ptr
)
322 else if (sec
== bfd_und_section_ptr
)
325 return (segment_info_type
*) bfd_get_section_userdata (stdoutput
, sec
);
329 section_symbol (segT sec
)
331 segment_info_type
*seginfo
= seg_info (sec
);
339 #ifndef EMIT_SECTION_SYMBOLS
340 #define EMIT_SECTION_SYMBOLS 1
343 if (! EMIT_SECTION_SYMBOLS
|| symbol_table_frozen
)
345 /* Here we know it won't be going into the symbol table. */
346 s
= symbol_create (sec
->symbol
->name
, sec
, 0, &zero_address_frag
);
351 s
= symbol_find (sec
->symbol
->name
);
352 /* We have to make sure it is the right symbol when we
353 have multiple sections with the same section name. */
355 || ((seg
= S_GET_SEGMENT (s
)) != sec
356 && seg
!= undefined_section
))
357 s
= symbol_new (sec
->symbol
->name
, sec
, 0, &zero_address_frag
);
358 else if (seg
== undefined_section
)
360 S_SET_SEGMENT (s
, sec
);
361 symbol_set_frag (s
, &zero_address_frag
);
365 S_CLEAR_EXTERNAL (s
);
367 /* Use the BFD section symbol, if possible. */
368 if (obj_sec_sym_ok_for_reloc (sec
))
369 symbol_set_bfdsym (s
, sec
->symbol
);
371 symbol_get_bfdsym (s
)->flags
|= BSF_SECTION_SYM
;
377 /* Return whether the specified segment is thought to hold text. */
380 subseg_text_p (segT sec
)
382 return (bfd_get_section_flags (stdoutput
, sec
) & SEC_CODE
) != 0;
385 /* Return non zero if SEC has at least one byte of data. It is
386 possible that we'll return zero even on a non-empty section because
387 we don't know all the fragment types, and it is possible that an
388 fr_fix == 0 one still contributes data. Think of this as
389 seg_definitely_not_empty_p. */
392 seg_not_empty_p (segT sec ATTRIBUTE_UNUSED
)
394 segment_info_type
*seginfo
= seg_info (sec
);
401 for (chain
= seginfo
->frchainP
; chain
; chain
= chain
->frch_next
)
403 for (frag
= chain
->frch_root
; frag
; frag
= frag
->fr_next
)
406 if (obstack_next_free (&chain
->frch_obstack
)
407 != chain
->frch_last
->fr_literal
)
414 subsegs_print_statistics (FILE *file
)
417 fprintf (file
, "frag chains:\n");
418 for (frchp
= frchain_root
; frchp
; frchp
= frchp
->frch_next
)
423 /* If frch_subseg is non-zero, it's probably been chained onto
424 the end of a previous subsection. Don't count it again. */
425 if (frchp
->frch_subseg
!= 0)
428 /* Skip gas-internal sections. */
429 if (segment_name (frchp
->frch_seg
)[0] == '*')
432 for (fragp
= frchp
->frch_root
; fragp
; fragp
= fragp
->fr_next
)
436 fprintf (file
, "\n");
437 fprintf (file
, "\t%p %-10s\t%10d frags\n", (void *) frchp
,
438 segment_name (frchp
->frch_seg
), count
);
442 /* end of subsegs.c */