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 */