1 /* subsegs.c - subsegments -
2 Copyright (C) 1987, 1990, 1991, 1992 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 2, 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
18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
21 * Segments & sub-segments.
29 frchainS
*frchain_root
, *frchain_now
;
33 segment_info_type segment_info
[SEG_MAXIMUM_ORDINAL
];
36 /* Commented in "subsegs.h". */
37 frchainS
*data0_frchainP
, *bss0_frchainP
;
39 #endif /* MANY_SEGMENTS */
40 char *const seg_name
[] =
44 "e0", "e1", "e2", "e3", "e4", "e5", "e6", "e7", "e8", "e9",
49 #endif /* MANY_SEGMENTS */
51 "ASSEMBLER-INTERNAL-LOGIC-ERROR!",
54 "transfert vector preload",
55 "transfert vector postload",
58 }; /* Used by error reporters, dumpers etc. */
59 #endif /* BFD_ASSEMBLER */
61 static void subseg_set_rest
PARAMS ((segT
, subsegT
));
66 /* Check table(s) seg_name[], seg_N_TYPE[] is in correct order */
67 #if !defined (MANY_SEGMENTS) && !defined (BFD_ASSEMBLER)
68 know (SEG_ABSOLUTE
== 0);
72 know (SEG_UNKNOWN
== 4);
75 know (SEG_DEBUG
== 7);
78 know (SEG_REGISTER
== 10);
79 know (SEG_MAXIMUM_ORDINAL
== SEG_REGISTER
);
82 obstack_begin (&frags
, 5000);
84 frchain_now
= NULL
; /* Warn new_subseg() that we are booting. */
85 /* Fake up 1st frag. It won't be used=> is ok if obstack...
86 pads the end of it for alignment. */
87 frag_now
= (fragS
*) obstack_alloc (&frags
, SIZEOF_STRUCT_FRAG
);
88 memset (frag_now
, SIZEOF_STRUCT_FRAG
, 0);
91 /* This 1st frag will not be in any frchain.
92 We simply give subseg_new somewhere to scribble. */
93 now_subseg
= 42; /* Lie for 1st call to subseg_new. */
97 for (i
= SEG_E0
; i
< SEG_UNKNOWN
; i
++)
100 segment_info
[i
].frchainP
= frchain_now
;
104 subseg_set (SEG_DATA
, 0); /* .data 0 */
105 data0_frchainP
= frchain_now
;
107 subseg_set (SEG_BSS
, 0);
108 bss0_frchainP
= frchain_now
;
110 #endif /* ! MANY_SEGMENTS */
111 #endif /* ! BFD_ASSEMBLER */
118 * Change the subsegment we are in, BUT DO NOT MAKE A NEW FRAG for the
119 * subsegment. If we are already in the correct subsegment, change nothing.
120 * This is used eg as a worker for subseg_set [which does make a new frag_now]
121 * and for changing segments after we have read the source. We construct eg
122 * fixSs even after the source file is read, so we do have to keep the
123 * segment context correct.
126 subseg_change (seg
, subseg
)
135 segment_info_type
*seginfo
;
136 seginfo
= (segment_info_type
*) bfd_get_section_userdata (stdoutput
, seg
);
139 seginfo
= (segment_info_type
*) xmalloc (sizeof (*seginfo
));
142 seginfo
->fix_root
= 0;
143 seginfo
->fix_tail
= 0;
144 seginfo
->bfd_section
= seg
;
146 bfd_set_section_userdata (stdoutput
, seg
, (char *) seginfo
);
151 seg_fix_rootP
= &segment_info
[seg
].fix_root
;
152 seg_fix_tailP
= &segment_info
[seg
].fix_tail
;
156 seg_fix_rootP
= &data_fix_root
;
157 seg_fix_tailP
= &data_fix_tail
;
159 else if (seg
== SEG_TEXT
)
161 seg_fix_rootP
= &text_fix_root
;
162 seg_fix_tailP
= &text_fix_tail
;
166 know (seg
== SEG_BSS
);
167 seg_fix_rootP
= &bss_fix_root
;
168 seg_fix_tailP
= &bss_fix_tail
;
176 subseg_set_rest (seg
, subseg
)
180 long tmp
; /* JF for obstack alignment hacking */
181 register frchainS
*frcP
; /* crawl frchain chain */
182 register frchainS
**lastPP
; /* address of last pointer */
183 frchainS
*newP
; /* address of new frchain */
184 register fragS
*former_last_fragP
;
185 register fragS
*new_fragP
;
187 if (frag_now
) /* If not bootstrapping. */
189 frag_now
->fr_fix
= (char*) obstack_next_free (&frags
) - frag_now
->fr_literal
;
190 frag_wane (frag_now
); /* Close off any frag in old subseg. */
193 * It would be nice to keep an obstack for each subsegment, if we swap
194 * subsegments a lot. Hence we would have much fewer frag_wanes().
197 obstack_finish (&frags
);
199 * If we don't do the above, the next object we put on obstack frags
200 * will appear to start at the fr_literal of the current frag.
201 * Also, above ensures that the next object will begin on a
202 * address that is aligned correctly for the engine that runs
206 subseg_change (seg
, (int) subseg
);
208 * Attempt to find or make a frchain for that sub seg.
209 * Crawl along chain of frchainSs, begins @ frchain_root.
210 * If we need to make a frchainS, link it into correct
211 * position of chain rooted in frchain_root.
213 for (frcP
= *(lastPP
= &frchain_root
);
214 frcP
&& (int) (frcP
->frch_seg
) <= (int) seg
;
215 frcP
= *(lastPP
= &frcP
->frch_next
))
217 if ((int) (frcP
->frch_seg
) == (int) seg
218 && frcP
->frch_subseg
>= subseg
)
224 * frcP: Address of the 1st frchainS in correct segment with
225 * frch_subseg >= subseg.
226 * We want to either use this frchainS, or we want
227 * to insert a new frchainS just before it.
229 * If frcP==NULL, then we are at the end of the chain
230 * of frchainS-s. A NULL frcP means we fell off the end
231 * of the chain looking for a
232 * frch_subseg >= subseg, so we
233 * must make a new frchainS.
235 * If we ever maintain a pointer to
236 * the last frchainS in the chain, we change that pointer
237 * ONLY when frcP==NULL.
239 * lastPP: Address of the pointer with value frcP;
241 * May point to frchain_root.
245 || ((int) (frcP
->frch_seg
) > (int) seg
246 || frcP
->frch_subseg
> subseg
)) /* Kinky logic only works with 2 segments. */
249 * This should be the only code that creates a frchainS.
251 newP
= (frchainS
*) obstack_alloc (&frags
, sizeof (frchainS
));
252 memset (newP
, sizeof (frchainS
), 0);
253 /* This begines on a good boundary because a obstack_done()
254 preceeded it. It implies an obstack_done(), so we expect
255 the next object allocated to begin on a correct boundary. */
257 newP
->frch_next
= frcP
; /* perhaps NULL */
258 (frcP
= newP
)->frch_subseg
= subseg
;
259 newP
->frch_seg
= seg
;
260 newP
->frch_last
= NULL
;
263 * Here with frcP ->ing to the frchainS for subseg.
267 * Make a fresh frag for the subsegment.
269 /* We expect this to happen on a correct boundary since it was
270 proceeded by a obstack_done(). */
271 tmp
= obstack_alignment_mask (&frags
); /* JF disable alignment */
272 obstack_alignment_mask (&frags
) = 0;
273 frag_now
= (fragS
*) obstack_alloc (&frags
, SIZEOF_STRUCT_FRAG
);
274 memset (frag_now
, 0, SIZEOF_STRUCT_FRAG
);
275 obstack_alignment_mask (&frags
) = tmp
;
276 /* But we want any more chars to come immediately after the
277 structure we just made. */
278 new_fragP
= frag_now
;
279 new_fragP
->fr_next
= NULL
;
281 * Append new frag to current frchain.
283 former_last_fragP
= frcP
->frch_last
;
284 if (former_last_fragP
)
286 know (former_last_fragP
->fr_next
== NULL
);
287 know (frchain_now
->frch_root
);
288 former_last_fragP
->fr_next
= new_fragP
;
292 frcP
->frch_root
= new_fragP
;
294 frcP
->frch_last
= new_fragP
;
298 * subseg_set(segT, subsegT)
300 * If you attempt to change to the current subsegment, nothing happens.
302 * In: segT, subsegT code for new subsegment.
303 * frag_now -> incomplete frag for current subsegment.
304 * If frag_now==NULL, then there is no old, incomplete frag, so
305 * the old frag is not closed off.
307 * Out: now_subseg, now_seg updated.
308 * Frchain_now points to the (possibly new) struct frchain for this
310 * Frchain_root updated if needed.
313 #ifndef BFD_ASSEMBLER
316 subseg_new (segname
, subseg
)
322 for (i
= 0; i
< (int) SEG_MAXIMUM_ORDINAL
; i
++)
326 s
= segment_name ((segT
) i
);
327 if (strcmp (segname
, s
) == 0
328 || (segname
[0] == '.'
329 && strcmp (segname
+ 1, s
) == 0))
331 subseg_set ((segT
) i
, subseg
);
334 #ifdef obj_segment_name
335 s
= obj_segment_name ((segT
) i
);
336 if (strcmp (segname
, s
) == 0
337 || (segname
[0] == '.'
338 && strcmp (segname
+ 1, s
) == 0))
340 subseg_set ((segT
) i
, subseg
);
346 #ifdef obj_add_segment
349 new_seg
= obj_add_segment (segname
);
350 subseg_set (new_seg
, subseg
);
354 as_bad ("Attempt to switch to nonexistent segment \"%s\"", segname
);
360 subseg_set (seg
, subseg
) /* begin assembly for a new sub-segment */
361 register segT seg
; /* SEG_DATA or SEG_TEXT */
362 register subsegT subseg
;
364 #ifndef MANY_SEGMENTS
365 know (seg
== SEG_DATA
|| seg
== SEG_TEXT
|| seg
== SEG_BSS
);
368 if (seg
!= now_seg
|| subseg
!= now_subseg
)
369 { /* we just changed sub-segments */
370 subseg_set_rest (seg
, subseg
);
374 #else /* BFD_ASSEMBLER */
377 subseg_new (segname
, subseg
)
382 segment_info_type
*seginfo
;
383 const char *now_seg_name
= (now_seg
384 ? bfd_get_section_name (stdoutput
, now_seg
)
388 && (now_seg_name
== segname
389 || !strcmp (now_seg_name
, segname
))
390 && subseg
== now_subseg
)
393 secptr
= bfd_make_section_old_way (stdoutput
, segname
);
394 seginfo
= seg_info (secptr
);
397 secptr
->output_section
= secptr
;
398 seginfo
= (segment_info_type
*) xmalloc (sizeof (*seginfo
));
399 seginfo
->fix_root
= 0;
400 seginfo
->fix_tail
= 0;
401 seginfo
->bfd_section
= secptr
;
402 bfd_set_section_userdata (stdoutput
, secptr
, (char *) seginfo
);
403 subseg_set_rest (secptr
, subseg
);
404 seginfo
->frchainP
= frchain_now
;
405 seginfo
->lineno_list_head
= seginfo
->lineno_list_tail
= 0;
409 seginfo
->user_stuff
= 0;
412 subseg_set_rest (secptr
, subseg
);
417 subseg_set (secptr
, subseg
)
421 if (! (secptr
== now_seg
&& subseg
== now_subseg
))
422 subseg_set_rest (secptr
, subseg
);
425 #endif /* BFD_ASSEMBLER */
427 /* end of subsegs.c */