1 /* Stabs in sections linking support.
2 Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003
3 Free Software Foundation, Inc.
4 Written by Ian Lance Taylor, Cygnus Support.
6 This file is part of BFD, the Binary File Descriptor library.
8 This program 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 of the License, or
11 (at your option) any later version.
13 This program 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 this program; if not, write to the Free Software
20 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
22 /* This file contains support for linking stabs in sections, as used
28 #include "aout/stab_gnu.h"
29 #include "safe-ctype.h"
31 /* Stabs entries use a 12 byte format:
32 4 byte string table index
34 1 byte stab other field
35 2 byte stab desc field
37 FIXME: This will have to change for a 64 bit object format.
39 The stabs symbols are divided into compilation units. For the
40 first entry in each unit, the type of 0, the value is the length of
41 the string table for this unit, and the desc field is the number of
42 stabs symbols for this unit. */
51 /* A hash table used for header files with N_BINCL entries. */
53 struct stab_link_includes_table
55 struct bfd_hash_table root;
58 /* A linked list of totals that we have found for a particular header
61 struct stab_link_includes_totals
63 struct stab_link_includes_totals *next;
67 /* An entry in the header file hash table. */
69 struct stab_link_includes_entry
71 struct bfd_hash_entry root;
72 /* List of totals we have found for this file. */
73 struct stab_link_includes_totals *totals;
76 /* Look up an entry in an the header file hash table. */
78 #define stab_link_includes_lookup(table, string, create, copy) \
79 ((struct stab_link_includes_entry *) \
80 bfd_hash_lookup (&(table)->root, (string), (create), (copy)))
82 /* This structure is used to hold a list of N_BINCL symbols, some of
83 which might be converted into N_EXCL symbols. */
87 /* The next symbol to convert. */
88 struct stab_excl_list *next;
89 /* The offset to this symbol in the section contents. */
91 /* The value to use for the symbol. */
93 /* The type of this symbol (N_BINCL or N_EXCL). */
97 /* This structure is stored with each .stab section. */
99 struct stab_section_info
101 /* This is a linked list of N_BINCL symbols which should be
102 converted into N_EXCL symbols. */
103 struct stab_excl_list *excls;
105 /* This is used to map input stab offsets within their sections
106 to output stab offsets, to take into account stabs that have
107 been deleted. If it is NULL, the output offsets are the same
108 as the input offsets, because no stabs have been deleted from
109 this section. Otherwise the i'th entry is the number of
110 bytes of stabs that have been deleted prior to the i'th
112 bfd_size_type *cumulative_skips;
114 /* This is an array of string indices. For each stab symbol, we
115 store the string index here. If a stab symbol should not be
116 included in the final output, the string index is -1. */
117 bfd_size_type stridxs[1];
120 /* This structure is used to keep track of stabs in sections
121 information while linking. */
125 /* A hash table used to hold stabs strings. */
126 struct bfd_strtab_hash *strings;
127 /* The header file hash table. */
128 struct stab_link_includes_table includes;
129 /* The first .stabstr section. */
133 static struct bfd_hash_entry *stab_link_includes_newfunc
134 PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *));
136 /* The function to create a new entry in the header file hash table. */
138 static struct bfd_hash_entry *
139 stab_link_includes_newfunc (entry, table, string)
140 struct bfd_hash_entry *entry;
141 struct bfd_hash_table *table;
144 struct stab_link_includes_entry *ret =
145 (struct stab_link_includes_entry *) entry;
147 /* Allocate the structure if it has not already been allocated by a
149 if (ret == (struct stab_link_includes_entry *) NULL)
150 ret = ((struct stab_link_includes_entry *)
151 bfd_hash_allocate (table,
152 sizeof (struct stab_link_includes_entry)));
153 if (ret == (struct stab_link_includes_entry *) NULL)
154 return (struct bfd_hash_entry *) ret;
156 /* Call the allocation method of the superclass. */
157 ret = ((struct stab_link_includes_entry *)
158 bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
161 /* Set local fields. */
165 return (struct bfd_hash_entry *) ret;
168 /* This function is called for each input file from the add_symbols
169 pass of the linker. */
172 _bfd_link_section_stabs (abfd, psinfo, stabsec, stabstrsec, psecinfo, pstring_offset)
176 asection *stabstrsec;
178 bfd_size_type *pstring_offset;
181 struct stab_info *sinfo;
182 bfd_size_type count, amt;
183 struct stab_section_info *secinfo;
184 bfd_byte *stabbuf = NULL;
185 bfd_byte *stabstrbuf = NULL;
186 bfd_byte *sym, *symend;
187 bfd_size_type stroff, next_stroff, skip;
188 bfd_size_type *pstridx;
190 if (stabsec->_raw_size == 0
191 || stabstrsec->_raw_size == 0)
193 /* This file does not contain stabs debugging information. */
197 if (stabsec->_raw_size % STABSIZE != 0)
199 /* Something is wrong with the format of these stab symbols.
200 Don't try to optimize them. */
204 if ((stabstrsec->flags & SEC_RELOC) != 0)
206 /* We shouldn't see relocations in the strings, and we aren't
207 prepared to handle them. */
211 if ((stabsec->output_section != NULL
212 && bfd_is_abs_section (stabsec->output_section))
213 || (stabstrsec->output_section != NULL
214 && bfd_is_abs_section (stabstrsec->output_section)))
216 /* At least one of the sections is being discarded from the
217 link, so we should just ignore them. */
225 /* Initialize the stabs information we need to keep track of. */
227 amt = sizeof (struct stab_info);
228 *psinfo = (PTR) bfd_alloc (abfd, amt);
231 sinfo = (struct stab_info *) *psinfo;
232 sinfo->strings = _bfd_stringtab_init ();
233 if (sinfo->strings == NULL)
235 /* Make sure the first byte is zero. */
236 (void) _bfd_stringtab_add (sinfo->strings, "", TRUE, TRUE);
237 if (! bfd_hash_table_init_n (&sinfo->includes.root,
238 stab_link_includes_newfunc,
241 sinfo->stabstr = bfd_make_section_anyway (abfd, ".stabstr");
242 sinfo->stabstr->flags |= SEC_HAS_CONTENTS | SEC_READONLY | SEC_DEBUGGING;
245 sinfo = (struct stab_info *) *psinfo;
247 /* Initialize the information we are going to store for this .stab
250 count = stabsec->_raw_size / STABSIZE;
252 amt = sizeof (struct stab_section_info);
253 amt += (count - 1) * sizeof (bfd_size_type);
254 *psecinfo = bfd_alloc (abfd, amt);
255 if (*psecinfo == NULL)
258 secinfo = (struct stab_section_info *) *psecinfo;
259 secinfo->excls = NULL;
260 secinfo->cumulative_skips = NULL;
261 memset (secinfo->stridxs, 0, (size_t) count * sizeof (bfd_size_type));
263 /* Read the stabs information from abfd. */
265 stabbuf = (bfd_byte *) bfd_malloc (stabsec->_raw_size);
266 stabstrbuf = (bfd_byte *) bfd_malloc (stabstrsec->_raw_size);
267 if (stabbuf == NULL || stabstrbuf == NULL)
270 if (! bfd_get_section_contents (abfd, stabsec, stabbuf, (bfd_vma) 0,
272 || ! bfd_get_section_contents (abfd, stabstrsec, stabstrbuf, (bfd_vma) 0,
273 stabstrsec->_raw_size))
276 /* Look through the stabs symbols, work out the new string indices,
277 and identify N_BINCL symbols which can be eliminated. */
280 /* The stabs sections can be split when
281 -split-by-reloc/-split-by-file is used. We must keep track of
282 each stab section's place in the single concatenated string
284 next_stroff = pstring_offset ? *pstring_offset : 0;
287 symend = stabbuf + stabsec->_raw_size;
288 for (sym = stabbuf, pstridx = secinfo->stridxs;
290 sym += STABSIZE, ++pstridx)
292 bfd_size_type symstroff;
298 /* This symbol has already been handled by an N_BINCL pass. */
306 /* Special type 0 stabs indicate the offset to the next
307 string table. We only copy the very first one. */
308 stroff = next_stroff;
309 next_stroff += bfd_get_32 (abfd, sym + 8);
311 *pstring_offset = next_stroff;
314 *pstridx = (bfd_size_type) -1;
321 /* Store the string in the hash table, and record the index. */
322 symstroff = stroff + bfd_get_32 (abfd, sym + STRDXOFF);
323 if (symstroff >= stabstrsec->_raw_size)
325 (*_bfd_error_handler)
326 (_("%s(%s+0x%lx): Stabs entry has invalid string index."),
327 bfd_archive_filename (abfd),
328 bfd_get_section_name (abfd, stabsec),
329 (long) (sym - stabbuf));
330 bfd_set_error (bfd_error_bad_value);
333 string = (char *) stabstrbuf + symstroff;
334 *pstridx = _bfd_stringtab_add (sinfo->strings, string, TRUE, TRUE);
336 /* An N_BINCL symbol indicates the start of the stabs entries
337 for a header file. We need to scan ahead to the next N_EINCL
338 symbol, ignoring nesting, adding up all the characters in the
339 symbol names, not including the file numbers in types (the
340 first number after an open parenthesis). */
341 if (type == (int) N_BINCL)
346 struct stab_link_includes_entry *incl_entry;
347 struct stab_link_includes_totals *t;
348 struct stab_excl_list *ne;
352 for (incl_sym = sym + STABSIZE;
354 incl_sym += STABSIZE)
358 incl_type = incl_sym[TYPEOFF];
361 else if (incl_type == (int) N_EINCL)
367 else if (incl_type == (int) N_BINCL)
373 str = ((char *) stabstrbuf
375 + bfd_get_32 (abfd, incl_sym + STRDXOFF));
376 for (; *str != '\0'; str++)
381 /* Skip the file number. */
383 while (ISDIGIT (*str))
391 /* If we have already included a header file with the same
392 value, then replaced this one with an N_EXCL symbol. */
393 incl_entry = stab_link_includes_lookup (&sinfo->includes, string,
395 if (incl_entry == NULL)
398 for (t = incl_entry->totals; t != NULL; t = t->next)
402 /* Record this symbol, so that we can set the value
405 ne = (struct stab_excl_list *) bfd_alloc (abfd, amt);
408 ne->offset = sym - stabbuf;
410 ne->type = (int) N_BINCL;
411 ne->next = secinfo->excls;
416 /* This is the first time we have seen this header file
417 with this set of stabs strings. */
418 t = ((struct stab_link_includes_totals *)
419 bfd_hash_allocate (&sinfo->includes.root, sizeof *t));
423 t->next = incl_entry->totals;
424 incl_entry->totals = t;
428 bfd_size_type *incl_pstridx;
430 /* We have seen this header file before. Tell the final
431 pass to change the type to N_EXCL. */
432 ne->type = (int) N_EXCL;
434 /* Mark the skipped symbols. */
437 for (incl_sym = sym + STABSIZE, incl_pstridx = pstridx + 1;
439 incl_sym += STABSIZE, ++incl_pstridx)
443 incl_type = incl_sym[TYPEOFF];
445 if (incl_type == (int) N_EINCL)
449 *incl_pstridx = (bfd_size_type) -1;
455 else if (incl_type == (int) N_BINCL)
459 *incl_pstridx = (bfd_size_type) -1;
472 /* We need to set the section sizes such that the linker will
473 compute the output section sizes correctly. We set the .stab
474 size to not include the entries we don't want. We set
475 SEC_EXCLUDE for the .stabstr section, so that it will be dropped
476 from the link. We record the size of the strtab in the first
477 .stabstr section we saw, and make sure we don't set SEC_EXCLUDE
479 stabsec->_cooked_size = (count - skip) * STABSIZE;
480 if (stabsec->_cooked_size == 0)
481 stabsec->flags |= SEC_EXCLUDE;
482 stabstrsec->flags |= SEC_EXCLUDE;
483 sinfo->stabstr->_cooked_size = _bfd_stringtab_size (sinfo->strings);
485 /* Calculate the `cumulative_skips' array now that stabs have been
486 deleted for this section. */
490 bfd_size_type i, offset;
491 bfd_size_type *pskips;
493 amt = count * sizeof (bfd_size_type);
494 secinfo->cumulative_skips = (bfd_size_type *) bfd_alloc (abfd, amt);
495 if (secinfo->cumulative_skips == NULL)
498 pskips = secinfo->cumulative_skips;
499 pstridx = secinfo->stridxs;
502 for (i = 0; i < count; i++, pskips++, pstridx++)
505 if (*pstridx == (bfd_size_type) -1)
509 BFD_ASSERT (offset != 0);
517 if (stabstrbuf != NULL)
523 /* This function is called for each input file before the stab
524 section is relocated. It discards stab entries for discarded
525 functions and variables. The function returns TRUE iff
526 any entries have been deleted.
530 _bfd_discard_section_stabs (abfd, stabsec, psecinfo,
531 reloc_symbol_deleted_p, cookie)
535 bfd_boolean (*reloc_symbol_deleted_p) PARAMS ((bfd_vma, PTR));
538 bfd_size_type count, amt;
539 struct stab_section_info *secinfo;
540 bfd_byte *stabbuf = NULL;
541 bfd_byte *sym, *symend;
543 bfd_size_type *pstridx;
546 if (stabsec->_raw_size == 0)
548 /* This file does not contain stabs debugging information. */
552 if (stabsec->_raw_size % STABSIZE != 0)
554 /* Something is wrong with the format of these stab symbols.
555 Don't try to optimize them. */
559 if ((stabsec->output_section != NULL
560 && bfd_is_abs_section (stabsec->output_section)))
562 /* At least one of the sections is being discarded from the
563 link, so we should just ignore them. */
567 /* We should have initialized our data in _bfd_link_stab_sections.
568 If there was some bizarre error reading the string sections, though,
569 we might not have. Bail rather than asserting. */
570 if (psecinfo == NULL)
573 count = stabsec->_raw_size / STABSIZE;
574 secinfo = (struct stab_section_info *) psecinfo;
576 /* Read the stabs information from abfd. */
578 stabbuf = (bfd_byte *) bfd_malloc (stabsec->_raw_size);
582 if (! bfd_get_section_contents (abfd, stabsec, stabbuf, (bfd_vma) 0,
586 /* Look through the stabs symbols and discard any information for
587 discarded functions. */
592 symend = stabbuf + stabsec->_raw_size;
593 for (sym = stabbuf, pstridx = secinfo->stridxs;
595 sym += STABSIZE, ++pstridx)
599 if (*pstridx == (bfd_size_type) -1)
601 /* This stab was deleted in a previous pass. */
607 if (type == (int) N_FUN)
609 int strx = bfd_get_32 (abfd, sym + STRDXOFF);
622 if ((*reloc_symbol_deleted_p) (sym + VALOFF - stabbuf, cookie))
631 else if (deleting == -1)
633 /* Outside of a function. Check for deleted variables. */
634 if (type == (int) N_STSYM || type == (int) N_LCSYM)
635 if ((*reloc_symbol_deleted_p) (sym + VALOFF - stabbuf, cookie))
640 /* We should also check for N_GSYM entries which reference a
641 deleted global, but those are less harmful to debuggers
642 and would require parsing the stab strings. */
649 /* Shrink the stabsec as needed. */
650 stabsec->_cooked_size -= skip * STABSIZE;
651 if (stabsec->_cooked_size == 0)
652 stabsec->flags |= SEC_EXCLUDE;
654 /* Recalculate the `cumulative_skips' array now that stabs have been
655 deleted for this section. */
659 bfd_size_type i, offset;
660 bfd_size_type *pskips;
662 if (secinfo->cumulative_skips == NULL)
664 amt = count * sizeof (bfd_size_type);
665 secinfo->cumulative_skips = (bfd_size_type *) bfd_alloc (abfd, amt);
666 if (secinfo->cumulative_skips == NULL)
670 pskips = secinfo->cumulative_skips;
671 pstridx = secinfo->stridxs;
674 for (i = 0; i < count; i++, pskips++, pstridx++)
677 if (*pstridx == (bfd_size_type) -1)
681 BFD_ASSERT (offset != 0);
692 /* Write out the stab section. This is called with the relocated
696 _bfd_write_section_stabs (output_bfd, psinfo, stabsec, psecinfo, contents)
703 struct stab_info *sinfo;
704 struct stab_section_info *secinfo;
705 struct stab_excl_list *e;
706 bfd_byte *sym, *tosym, *symend;
707 bfd_size_type *pstridx;
709 sinfo = (struct stab_info *) *psinfo;
710 secinfo = (struct stab_section_info *) *psecinfo;
713 return bfd_set_section_contents (output_bfd, stabsec->output_section,
715 (file_ptr) stabsec->output_offset,
718 /* Handle each N_BINCL entry. */
719 for (e = secinfo->excls; e != NULL; e = e->next)
723 BFD_ASSERT (e->offset < stabsec->_raw_size);
724 excl_sym = contents + e->offset;
725 bfd_put_32 (output_bfd, e->val, excl_sym + VALOFF);
726 excl_sym[TYPEOFF] = e->type;
729 /* Copy over all the stabs symbols, omitting the ones we don't want,
730 and correcting the string indices for those we do want. */
732 symend = contents + stabsec->_raw_size;
733 for (sym = contents, pstridx = secinfo->stridxs;
735 sym += STABSIZE, ++pstridx)
737 if (*pstridx != (bfd_size_type) -1)
740 memcpy (tosym, sym, STABSIZE);
741 bfd_put_32 (output_bfd, *pstridx, tosym + STRDXOFF);
743 if (sym[TYPEOFF] == 0)
745 /* This is the header symbol for the stabs section. We
746 don't really need one, since we have merged all the
747 input stabs sections into one, but we generate one
748 for the benefit of readers which expect to see one. */
749 BFD_ASSERT (sym == contents);
750 bfd_put_32 (output_bfd, _bfd_stringtab_size (sinfo->strings),
752 bfd_put_16 (output_bfd,
753 stabsec->output_section->_raw_size / STABSIZE - 1,
761 BFD_ASSERT ((bfd_size_type) (tosym - contents) == stabsec->_cooked_size);
763 return bfd_set_section_contents (output_bfd, stabsec->output_section,
764 contents, (file_ptr) stabsec->output_offset,
765 stabsec->_cooked_size);
768 /* Write out the .stabstr section. */
771 _bfd_write_stab_strings (output_bfd, psinfo)
775 struct stab_info *sinfo;
777 sinfo = (struct stab_info *) *psinfo;
782 if (bfd_is_abs_section (sinfo->stabstr->output_section))
784 /* The section was discarded from the link. */
788 BFD_ASSERT ((sinfo->stabstr->output_offset
789 + _bfd_stringtab_size (sinfo->strings))
790 <= sinfo->stabstr->output_section->_raw_size);
792 if (bfd_seek (output_bfd,
793 (file_ptr) (sinfo->stabstr->output_section->filepos
794 + sinfo->stabstr->output_offset),
798 if (! _bfd_stringtab_emit (output_bfd, sinfo->strings))
801 /* We no longer need the stabs information. */
802 _bfd_stringtab_free (sinfo->strings);
803 bfd_hash_table_free (&sinfo->includes.root);
808 /* Adjust an address in the .stab section. Given OFFSET within
809 STABSEC, this returns the new offset in the adjusted stab section,
810 or -1 if the address refers to a stab which has been removed. */
813 _bfd_stab_section_offset (output_bfd, psinfo, stabsec, psecinfo, offset)
814 bfd *output_bfd ATTRIBUTE_UNUSED;
815 PTR *psinfo ATTRIBUTE_UNUSED;
820 struct stab_section_info *secinfo;
822 secinfo = (struct stab_section_info *) *psecinfo;
827 if (offset >= stabsec->_raw_size)
828 return offset - (stabsec->_cooked_size - stabsec->_raw_size);
830 if (secinfo->cumulative_skips)
834 i = offset / STABSIZE;
836 if (secinfo->stridxs [i] == (bfd_size_type) -1)
839 return offset - secinfo->cumulative_skips [i];