Commit | Line | Data |
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252b5132 | 1 | /* subsegs.c - subsegments - |
f7e42eb4 | 2 | Copyright 1987, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, |
f592407e | 3 | 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 |
252b5132 RH |
4 | Free Software Foundation, Inc. |
5 | ||
6 | This file is part of GAS, the GNU Assembler. | |
7 | ||
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) | |
11 | any later version. | |
12 | ||
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. | |
17 | ||
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 | |
4b4da160 NC |
20 | Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA |
21 | 02110-1301, USA. */ | |
252b5132 | 22 | |
ef99799a | 23 | /* Segments & sub-segments. */ |
252b5132 RH |
24 | |
25 | #include "as.h" | |
26 | ||
27 | #include "subsegs.h" | |
28 | #include "obstack.h" | |
29 | ||
30 | frchainS *frchain_root, *frchain_now; | |
31 | ||
32 | static struct obstack frchains; | |
33 | ||
252b5132 RH |
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; | |
38 | ||
24361518 | 39 | static void subseg_set_rest (segT, subsegT); |
252b5132 RH |
40 | |
41 | static fragS dummy_frag; | |
42 | ||
43 | static frchainS absolute_frchain; | |
44 | \f | |
45 | void | |
24361518 | 46 | subsegs_begin (void) |
252b5132 | 47 | { |
252b5132 RH |
48 | obstack_begin (&frchains, chunksize); |
49 | #if __GNUC__ >= 2 | |
50 | obstack_alignment_mask (&frchains) = __alignof__ (frchainS) - 1; | |
51 | #endif | |
52 | ||
53 | frchain_root = NULL; | |
f0e652b4 | 54 | frchain_now = NULL; /* Warn new_subseg() that we are booting. */ |
252b5132 RH |
55 | |
56 | frag_now = &dummy_frag; | |
57 | ||
252b5132 RH |
58 | absolute_frchain.frch_seg = absolute_section; |
59 | absolute_frchain.frch_subseg = 0; | |
252b5132 | 60 | absolute_frchain.fix_root = absolute_frchain.fix_tail = 0; |
252b5132 RH |
61 | absolute_frchain.frch_frag_now = &zero_address_frag; |
62 | absolute_frchain.frch_root = absolute_frchain.frch_last = &zero_address_frag; | |
63 | } | |
64 | \f | |
65 | /* | |
66 | * subseg_change() | |
67 | * | |
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. | |
74 | */ | |
75 | void | |
24361518 | 76 | subseg_change (register segT seg, register int subseg) |
252b5132 | 77 | { |
4924bf8f | 78 | segment_info_type *seginfo; |
252b5132 RH |
79 | now_seg = seg; |
80 | now_subseg = subseg; | |
81 | ||
82 | if (now_seg == absolute_section) | |
83 | return; | |
84 | ||
7be1c489 AM |
85 | seginfo = (segment_info_type *) bfd_get_section_userdata (stdoutput, seg); |
86 | if (! seginfo) | |
252b5132 | 87 | { |
7be1c489 AM |
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; | |
93 | seginfo->sym = 0; | |
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; | |
98 | else | |
99 | bfd_set_section_userdata (stdoutput, seg, (PTR) seginfo); | |
252b5132 | 100 | } |
252b5132 RH |
101 | } |
102 | \f | |
103 | static void | |
24361518 | 104 | subseg_set_rest (segT seg, subsegT subseg) |
252b5132 RH |
105 | { |
106 | register frchainS *frcP; /* crawl frchain chain */ | |
107 | register frchainS **lastPP; /* address of last pointer */ | |
108 | frchainS *newP; /* address of new frchain */ | |
109 | ||
110 | mri_common_symbol = NULL; | |
111 | ||
112 | if (frag_now && frchain_now) | |
113 | frchain_now->frch_frag_now = frag_now; | |
114 | ||
115 | assert (frchain_now == 0 | |
116 | || now_seg == undefined_section | |
117 | || now_seg == absolute_section | |
118 | || frchain_now->frch_last == frag_now); | |
119 | ||
120 | subseg_change (seg, (int) subseg); | |
121 | ||
122 | if (seg == absolute_section) | |
123 | { | |
124 | frchain_now = &absolute_frchain; | |
125 | frag_now = &zero_address_frag; | |
126 | return; | |
127 | } | |
128 | ||
129 | assert (frchain_now == 0 | |
130 | || now_seg == undefined_section | |
131 | || frchain_now->frch_last == frag_now); | |
132 | ||
133 | /* | |
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. | |
138 | */ | |
139 | for (frcP = *(lastPP = &frchain_root); | |
140 | frcP && frcP->frch_seg <= seg; | |
141 | frcP = *(lastPP = &frcP->frch_next)) | |
142 | { | |
143 | if (frcP->frch_seg == seg | |
144 | && frcP->frch_subseg >= subseg) | |
145 | { | |
146 | break; | |
147 | } | |
148 | } | |
149 | /* | |
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. | |
154 | * | |
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. | |
160 | * | |
161 | * If we ever maintain a pointer to | |
162 | * the last frchainS in the chain, we change that pointer | |
163 | * ONLY when frcP==NULL. | |
164 | * | |
165 | * lastPP: Address of the pointer with value frcP; | |
166 | * Never NULL. | |
167 | * May point to frchain_root. | |
168 | * | |
169 | */ | |
170 | if (!frcP | |
171 | || (frcP->frch_seg > seg | |
f0e652b4 | 172 | || frcP->frch_subseg > subseg)) /* Kinky logic only works with 2 segments. */ |
252b5132 RH |
173 | { |
174 | /* | |
175 | * This should be the only code that creates a frchainS. | |
176 | */ | |
7be1c489 AM |
177 | segment_info_type *seginfo; |
178 | ||
252b5132 RH |
179 | newP = (frchainS *) obstack_alloc (&frchains, sizeof (frchainS)); |
180 | newP->frch_subseg = subseg; | |
181 | newP->frch_seg = seg; | |
252b5132 RH |
182 | newP->fix_root = NULL; |
183 | newP->fix_tail = NULL; | |
252b5132 RH |
184 | obstack_begin (&newP->frch_obstack, chunksize); |
185 | #if __GNUC__ >= 2 | |
186 | obstack_alignment_mask (&newP->frch_obstack) = __alignof__ (fragS) - 1; | |
187 | #endif | |
188 | newP->frch_frag_now = frag_alloc (&newP->frch_obstack); | |
189 | newP->frch_frag_now->fr_type = rs_fill; | |
190 | ||
191 | newP->frch_root = newP->frch_last = newP->frch_frag_now; | |
192 | ||
193 | *lastPP = newP; | |
194 | newP->frch_next = frcP; /* perhaps NULL */ | |
195 | ||
7be1c489 | 196 | seginfo = seg_info (seg); |
c35da140 | 197 | if (seginfo && (!seginfo->frchainP || seginfo->frchainP == frcP)) |
7be1c489 | 198 | seginfo->frchainP = newP; |
f0e652b4 | 199 | |
252b5132 RH |
200 | frcP = newP; |
201 | } | |
202 | /* | |
203 | * Here with frcP pointing to the frchainS for subseg. | |
204 | */ | |
205 | frchain_now = frcP; | |
206 | frag_now = frcP->frch_frag_now; | |
207 | ||
208 | assert (frchain_now->frch_last == frag_now); | |
209 | } | |
210 | ||
211 | /* | |
212 | * subseg_set(segT, subsegT) | |
213 | * | |
214 | * If you attempt to change to the current subsegment, nothing happens. | |
215 | * | |
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. | |
220 | * | |
221 | * Out: now_subseg, now_seg updated. | |
222 | * Frchain_now points to the (possibly new) struct frchain for this | |
223 | * sub-segment. | |
224 | * Frchain_root updated if needed. | |
225 | */ | |
226 | ||
252b5132 | 227 | segT |
24361518 | 228 | subseg_get (const char *segname, int force_new) |
252b5132 RH |
229 | { |
230 | segT secptr; | |
231 | segment_info_type *seginfo; | |
232 | const char *now_seg_name = (now_seg | |
233 | ? bfd_get_section_name (stdoutput, now_seg) | |
234 | : 0); | |
235 | ||
236 | if (!force_new | |
237 | && now_seg_name | |
238 | && (now_seg_name == segname | |
239 | || !strcmp (now_seg_name, segname))) | |
240 | return now_seg; | |
241 | ||
242 | if (!force_new) | |
243 | secptr = bfd_make_section_old_way (stdoutput, segname); | |
244 | else | |
245 | secptr = bfd_make_section_anyway (stdoutput, segname); | |
246 | ||
247 | seginfo = seg_info (secptr); | |
248 | if (! seginfo) | |
249 | { | |
250 | /* Check whether output_section is set first because secptr may | |
546c73f9 | 251 | be bfd_abs_section_ptr. */ |
252b5132 RH |
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; | |
263 | else | |
264 | bfd_set_section_userdata (stdoutput, secptr, (PTR) seginfo); | |
265 | seginfo->frchainP = NULL; | |
266 | seginfo->lineno_list_head = seginfo->lineno_list_tail = NULL; | |
267 | seginfo->sym = NULL; | |
268 | seginfo->dot = NULL; | |
269 | } | |
270 | return secptr; | |
271 | } | |
272 | ||
273 | segT | |
24361518 | 274 | subseg_new (const char *segname, subsegT subseg) |
252b5132 RH |
275 | { |
276 | segT secptr; | |
277 | segment_info_type *seginfo; | |
278 | ||
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; | |
284 | return secptr; | |
285 | } | |
286 | ||
287 | /* Like subseg_new, except a new section is always created, even if | |
288 | a section with that name already exists. */ | |
289 | segT | |
24361518 | 290 | subseg_force_new (const char *segname, subsegT subseg) |
252b5132 RH |
291 | { |
292 | segT secptr; | |
293 | segment_info_type *seginfo; | |
294 | ||
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; | |
300 | return secptr; | |
301 | } | |
302 | ||
303 | void | |
24361518 | 304 | subseg_set (segT secptr, subsegT subseg) |
252b5132 RH |
305 | { |
306 | if (! (secptr == now_seg && subseg == now_subseg)) | |
307 | subseg_set_rest (secptr, subseg); | |
308 | mri_common_symbol = NULL; | |
309 | } | |
310 | ||
311 | #ifndef obj_sec_sym_ok_for_reloc | |
312 | #define obj_sec_sym_ok_for_reloc(SEC) 0 | |
313 | #endif | |
314 | ||
315 | /* Get the gas information we are storing for a section. */ | |
316 | ||
317 | segment_info_type * | |
24361518 | 318 | seg_info (segT sec) |
252b5132 RH |
319 | { |
320 | if (sec == bfd_abs_section_ptr) | |
321 | return abs_seg_info; | |
322 | else if (sec == bfd_und_section_ptr) | |
323 | return und_seg_info; | |
324 | else | |
325 | return (segment_info_type *) bfd_get_section_userdata (stdoutput, sec); | |
326 | } | |
327 | ||
328 | symbolS * | |
24361518 | 329 | section_symbol (segT sec) |
252b5132 RH |
330 | { |
331 | segment_info_type *seginfo = seg_info (sec); | |
332 | symbolS *s; | |
333 | ||
334 | if (seginfo == 0) | |
335 | abort (); | |
336 | if (seginfo->sym) | |
337 | return seginfo->sym; | |
338 | ||
339 | #ifndef EMIT_SECTION_SYMBOLS | |
340 | #define EMIT_SECTION_SYMBOLS 1 | |
341 | #endif | |
342 | ||
a161fe53 | 343 | if (! EMIT_SECTION_SYMBOLS || symbol_table_frozen) |
252b5132 RH |
344 | { |
345 | /* Here we know it won't be going into the symbol table. */ | |
546c73f9 | 346 | s = symbol_create (sec->symbol->name, sec, 0, &zero_address_frag); |
252b5132 RH |
347 | } |
348 | else | |
349 | { | |
90c1602c | 350 | segT seg; |
91c4c449 | 351 | s = symbol_find (sec->symbol->name); |
22fe14ad NC |
352 | /* We have to make sure it is the right symbol when we |
353 | have multiple sections with the same section name. */ | |
90c1602c L |
354 | if (s == NULL |
355 | || ((seg = S_GET_SEGMENT (s)) != sec | |
356 | && seg != undefined_section)) | |
546c73f9 | 357 | s = symbol_new (sec->symbol->name, sec, 0, &zero_address_frag); |
90c1602c | 358 | else if (seg == undefined_section) |
252b5132 | 359 | { |
90c1602c L |
360 | S_SET_SEGMENT (s, sec); |
361 | symbol_set_frag (s, &zero_address_frag); | |
252b5132 RH |
362 | } |
363 | } | |
364 | ||
365 | S_CLEAR_EXTERNAL (s); | |
366 | ||
367 | /* Use the BFD section symbol, if possible. */ | |
368 | if (obj_sec_sym_ok_for_reloc (sec)) | |
49309057 | 369 | symbol_set_bfdsym (s, sec->symbol); |
a161fe53 AM |
370 | else |
371 | symbol_get_bfdsym (s)->flags |= BSF_SECTION_SYM; | |
252b5132 RH |
372 | |
373 | seginfo->sym = s; | |
374 | return s; | |
375 | } | |
376 | ||
b9e57a38 ILT |
377 | /* Return whether the specified segment is thought to hold text. */ |
378 | ||
379 | int | |
24361518 | 380 | subseg_text_p (segT sec) |
b9e57a38 | 381 | { |
b9e57a38 | 382 | return (bfd_get_section_flags (stdoutput, sec) & SEC_CODE) != 0; |
b9e57a38 ILT |
383 | } |
384 | ||
c6cb92c5 NS |
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. */ | |
390 | ||
4ee4d249 | 391 | int |
f17c130b | 392 | seg_not_empty_p (segT sec ATTRIBUTE_UNUSED) |
c6cb92c5 NS |
393 | { |
394 | segment_info_type *seginfo = seg_info (sec); | |
395 | frchainS *chain; | |
396 | fragS *frag; | |
397 | ||
398 | if (!seginfo) | |
399 | return 0; | |
400 | ||
401 | for (chain = seginfo->frchainP; chain; chain = chain->frch_next) | |
402 | { | |
403 | for (frag = chain->frch_root; frag; frag = frag->fr_next) | |
404 | if (frag->fr_fix) | |
405 | return 1; | |
406 | if (obstack_next_free (&chain->frch_obstack) | |
407 | != chain->frch_last->fr_literal) | |
408 | return 1; | |
409 | } | |
410 | return 0; | |
411 | } | |
412 | ||
252b5132 | 413 | void |
24361518 | 414 | subsegs_print_statistics (FILE *file) |
252b5132 RH |
415 | { |
416 | frchainS *frchp; | |
417 | fprintf (file, "frag chains:\n"); | |
418 | for (frchp = frchain_root; frchp; frchp = frchp->frch_next) | |
419 | { | |
420 | int count = 0; | |
421 | fragS *fragp; | |
422 | ||
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) | |
426 | continue; | |
427 | ||
428 | /* Skip gas-internal sections. */ | |
429 | if (segment_name (frchp->frch_seg)[0] == '*') | |
430 | continue; | |
431 | ||
432 | for (fragp = frchp->frch_root; fragp; fragp = fragp->fr_next) | |
433 | { | |
252b5132 RH |
434 | count++; |
435 | } | |
436 | fprintf (file, "\n"); | |
03e83a45 | 437 | fprintf (file, "\t%p %-10s\t%10d frags\n", (void *) frchp, |
252b5132 RH |
438 | segment_name (frchp->frch_seg), count); |
439 | } | |
440 | } | |
441 | ||
442 | /* end of subsegs.c */ |