1 /* Stabs in sections linking support.
2 Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002
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
)
176 asection
*stabstrsec
;
180 struct stab_info
*sinfo
;
181 bfd_size_type count
, amt
;
182 struct stab_section_info
*secinfo
;
183 bfd_byte
*stabbuf
= NULL
;
184 bfd_byte
*stabstrbuf
= NULL
;
185 bfd_byte
*sym
, *symend
;
186 bfd_size_type stroff
, next_stroff
, skip
;
187 bfd_size_type
*pstridx
;
189 if (stabsec
->_raw_size
== 0
190 || stabstrsec
->_raw_size
== 0)
192 /* This file does not contain stabs debugging information. */
196 if (stabsec
->_raw_size
% STABSIZE
!= 0)
198 /* Something is wrong with the format of these stab symbols.
199 Don't try to optimize them. */
203 if ((stabstrsec
->flags
& SEC_RELOC
) != 0)
205 /* We shouldn't see relocations in the strings, and we aren't
206 prepared to handle them. */
210 if ((stabsec
->output_section
!= NULL
211 && bfd_is_abs_section (stabsec
->output_section
))
212 || (stabstrsec
->output_section
!= NULL
213 && bfd_is_abs_section (stabstrsec
->output_section
)))
215 /* At least one of the sections is being discarded from the
216 link, so we should just ignore them. */
224 /* Initialize the stabs information we need to keep track of. */
226 amt
= sizeof (struct stab_info
);
227 *psinfo
= (PTR
) bfd_alloc (abfd
, amt
);
230 sinfo
= (struct stab_info
*) *psinfo
;
231 sinfo
->strings
= _bfd_stringtab_init ();
232 if (sinfo
->strings
== NULL
)
234 /* Make sure the first byte is zero. */
235 (void) _bfd_stringtab_add (sinfo
->strings
, "", TRUE
, TRUE
);
236 if (! bfd_hash_table_init_n (&sinfo
->includes
.root
,
237 stab_link_includes_newfunc
,
240 sinfo
->stabstr
= bfd_make_section_anyway (abfd
, ".stabstr");
241 sinfo
->stabstr
->flags
|= SEC_HAS_CONTENTS
| SEC_READONLY
| SEC_DEBUGGING
;
244 sinfo
= (struct stab_info
*) *psinfo
;
246 /* Initialize the information we are going to store for this .stab
249 count
= stabsec
->_raw_size
/ STABSIZE
;
251 amt
= sizeof (struct stab_section_info
);
252 amt
+= (count
- 1) * sizeof (bfd_size_type
);
253 *psecinfo
= bfd_alloc (abfd
, amt
);
254 if (*psecinfo
== NULL
)
257 secinfo
= (struct stab_section_info
*) *psecinfo
;
258 secinfo
->excls
= NULL
;
259 secinfo
->cumulative_skips
= NULL
;
260 memset (secinfo
->stridxs
, 0, (size_t) count
* sizeof (bfd_size_type
));
262 /* Read the stabs information from abfd. */
264 stabbuf
= (bfd_byte
*) bfd_malloc (stabsec
->_raw_size
);
265 stabstrbuf
= (bfd_byte
*) bfd_malloc (stabstrsec
->_raw_size
);
266 if (stabbuf
== NULL
|| stabstrbuf
== NULL
)
269 if (! bfd_get_section_contents (abfd
, stabsec
, stabbuf
, (bfd_vma
) 0,
271 || ! bfd_get_section_contents (abfd
, stabstrsec
, stabstrbuf
, (bfd_vma
) 0,
272 stabstrsec
->_raw_size
))
275 /* Look through the stabs symbols, work out the new string indices,
276 and identify N_BINCL symbols which can be eliminated. */
282 symend
= stabbuf
+ stabsec
->_raw_size
;
283 for (sym
= stabbuf
, pstridx
= secinfo
->stridxs
;
285 sym
+= STABSIZE
, ++pstridx
)
287 bfd_size_type symstroff
;
293 /* This symbol has already been handled by an N_BINCL pass. */
301 /* Special type 0 stabs indicate the offset to the next
302 string table. We only copy the very first one. */
303 stroff
= next_stroff
;
304 next_stroff
+= bfd_get_32 (abfd
, sym
+ 8);
307 *pstridx
= (bfd_size_type
) -1;
314 /* Store the string in the hash table, and record the index. */
315 symstroff
= stroff
+ bfd_get_32 (abfd
, sym
+ STRDXOFF
);
316 if (symstroff
>= stabstrsec
->_raw_size
)
318 (*_bfd_error_handler
)
319 (_("%s(%s+0x%lx): Stabs entry has invalid string index."),
320 bfd_archive_filename (abfd
),
321 bfd_get_section_name (abfd
, stabsec
),
322 (long) (sym
- stabbuf
));
323 bfd_set_error (bfd_error_bad_value
);
326 string
= (char *) stabstrbuf
+ symstroff
;
327 *pstridx
= _bfd_stringtab_add (sinfo
->strings
, string
, TRUE
, TRUE
);
329 /* An N_BINCL symbol indicates the start of the stabs entries
330 for a header file. We need to scan ahead to the next N_EINCL
331 symbol, ignoring nesting, adding up all the characters in the
332 symbol names, not including the file numbers in types (the
333 first number after an open parenthesis). */
334 if (type
== (int) N_BINCL
)
339 struct stab_link_includes_entry
*incl_entry
;
340 struct stab_link_includes_totals
*t
;
341 struct stab_excl_list
*ne
;
345 for (incl_sym
= sym
+ STABSIZE
;
347 incl_sym
+= STABSIZE
)
351 incl_type
= incl_sym
[TYPEOFF
];
354 else if (incl_type
== (int) N_EINCL
)
360 else if (incl_type
== (int) N_BINCL
)
366 str
= ((char *) stabstrbuf
368 + bfd_get_32 (abfd
, incl_sym
+ STRDXOFF
));
369 for (; *str
!= '\0'; str
++)
374 /* Skip the file number. */
376 while (ISDIGIT (*str
))
384 /* If we have already included a header file with the same
385 value, then replaced this one with an N_EXCL symbol. */
386 incl_entry
= stab_link_includes_lookup (&sinfo
->includes
, string
,
388 if (incl_entry
== NULL
)
391 for (t
= incl_entry
->totals
; t
!= NULL
; t
= t
->next
)
395 /* Record this symbol, so that we can set the value
398 ne
= (struct stab_excl_list
*) bfd_alloc (abfd
, amt
);
401 ne
->offset
= sym
- stabbuf
;
403 ne
->type
= (int) N_BINCL
;
404 ne
->next
= secinfo
->excls
;
409 /* This is the first time we have seen this header file
410 with this set of stabs strings. */
411 t
= ((struct stab_link_includes_totals
*)
412 bfd_hash_allocate (&sinfo
->includes
.root
, sizeof *t
));
416 t
->next
= incl_entry
->totals
;
417 incl_entry
->totals
= t
;
421 bfd_size_type
*incl_pstridx
;
423 /* We have seen this header file before. Tell the final
424 pass to change the type to N_EXCL. */
425 ne
->type
= (int) N_EXCL
;
427 /* Mark the skipped symbols. */
430 for (incl_sym
= sym
+ STABSIZE
, incl_pstridx
= pstridx
+ 1;
432 incl_sym
+= STABSIZE
, ++incl_pstridx
)
436 incl_type
= incl_sym
[TYPEOFF
];
438 if (incl_type
== (int) N_EINCL
)
442 *incl_pstridx
= (bfd_size_type
) -1;
448 else if (incl_type
== (int) N_BINCL
)
452 *incl_pstridx
= (bfd_size_type
) -1;
465 /* We need to set the section sizes such that the linker will
466 compute the output section sizes correctly. We set the .stab
467 size to not include the entries we don't want. We set
468 SEC_EXCLUDE for the .stabstr section, so that it will be dropped
469 from the link. We record the size of the strtab in the first
470 .stabstr section we saw, and make sure we don't set SEC_EXCLUDE
472 stabsec
->_cooked_size
= (count
- skip
) * STABSIZE
;
473 if (stabsec
->_cooked_size
== 0)
474 stabsec
->flags
|= SEC_EXCLUDE
;
475 stabstrsec
->flags
|= SEC_EXCLUDE
;
476 sinfo
->stabstr
->_cooked_size
= _bfd_stringtab_size (sinfo
->strings
);
478 /* Calculate the `cumulative_skips' array now that stabs have been
479 deleted for this section. */
483 bfd_size_type i
, offset
;
484 bfd_size_type
*pskips
;
486 amt
= count
* sizeof (bfd_size_type
);
487 secinfo
->cumulative_skips
= (bfd_size_type
*) bfd_alloc (abfd
, amt
);
488 if (secinfo
->cumulative_skips
== NULL
)
491 pskips
= secinfo
->cumulative_skips
;
492 pstridx
= secinfo
->stridxs
;
495 for (i
= 0; i
< count
; i
++, pskips
++, pstridx
++)
498 if (*pstridx
== (bfd_size_type
) -1)
502 BFD_ASSERT (offset
!= 0);
510 if (stabstrbuf
!= NULL
)
516 /* This function is called for each input file before the stab
517 section is relocated. It discards stab entries for discarded
518 functions and variables. The function returns TRUE iff
519 any entries have been deleted.
523 _bfd_discard_section_stabs (abfd
, stabsec
, psecinfo
,
524 reloc_symbol_deleted_p
, cookie
)
528 bfd_boolean (*reloc_symbol_deleted_p
) PARAMS ((bfd_vma
, PTR
));
531 bfd_size_type count
, amt
;
532 struct stab_section_info
*secinfo
;
533 bfd_byte
*stabbuf
= NULL
;
534 bfd_byte
*sym
, *symend
;
536 bfd_size_type
*pstridx
;
539 if (stabsec
->_raw_size
== 0)
541 /* This file does not contain stabs debugging information. */
545 if (stabsec
->_raw_size
% STABSIZE
!= 0)
547 /* Something is wrong with the format of these stab symbols.
548 Don't try to optimize them. */
552 if ((stabsec
->output_section
!= NULL
553 && bfd_is_abs_section (stabsec
->output_section
)))
555 /* At least one of the sections is being discarded from the
556 link, so we should just ignore them. */
560 /* We should have initialized our data in _bfd_link_stab_sections.
561 If there was some bizarre error reading the string sections, though,
562 we might not have. Bail rather than asserting. */
563 if (psecinfo
== NULL
)
566 count
= stabsec
->_raw_size
/ STABSIZE
;
567 secinfo
= (struct stab_section_info
*) psecinfo
;
569 /* Read the stabs information from abfd. */
571 stabbuf
= (bfd_byte
*) bfd_malloc (stabsec
->_raw_size
);
575 if (! bfd_get_section_contents (abfd
, stabsec
, stabbuf
, (bfd_vma
) 0,
579 /* Look through the stabs symbols and discard any information for
580 discarded functions. */
585 symend
= stabbuf
+ stabsec
->_raw_size
;
586 for (sym
= stabbuf
, pstridx
= secinfo
->stridxs
;
588 sym
+= STABSIZE
, ++pstridx
)
592 if (*pstridx
== (bfd_size_type
) -1)
594 /* This stab was deleted in a previous pass. */
600 if (type
== (int) N_FUN
)
602 int strx
= bfd_get_32 (abfd
, sym
+ STRDXOFF
);
615 if ((*reloc_symbol_deleted_p
) (sym
+ VALOFF
- stabbuf
, cookie
))
624 else if (deleting
== -1)
626 /* Outside of a function. Check for deleted variables. */
627 if (type
== (int) N_STSYM
|| type
== (int) N_LCSYM
)
628 if ((*reloc_symbol_deleted_p
) (sym
+ VALOFF
- stabbuf
, cookie
))
633 /* We should also check for N_GSYM entries which reference a
634 deleted global, but those are less harmful to debuggers
635 and would require parsing the stab strings. */
642 /* Shrink the stabsec as needed. */
643 stabsec
->_cooked_size
-= skip
* STABSIZE
;
644 if (stabsec
->_cooked_size
== 0)
645 stabsec
->flags
|= SEC_EXCLUDE
;
647 /* Recalculate the `cumulative_skips' array now that stabs have been
648 deleted for this section. */
652 bfd_size_type i
, offset
;
653 bfd_size_type
*pskips
;
655 if (secinfo
->cumulative_skips
== NULL
)
657 amt
= count
* sizeof (bfd_size_type
);
658 secinfo
->cumulative_skips
= (bfd_size_type
*) bfd_alloc (abfd
, amt
);
659 if (secinfo
->cumulative_skips
== NULL
)
663 pskips
= secinfo
->cumulative_skips
;
664 pstridx
= secinfo
->stridxs
;
667 for (i
= 0; i
< count
; i
++, pskips
++, pstridx
++)
670 if (*pstridx
== (bfd_size_type
) -1)
674 BFD_ASSERT (offset
!= 0);
685 /* Write out the stab section. This is called with the relocated
689 _bfd_write_section_stabs (output_bfd
, psinfo
, stabsec
, psecinfo
, contents
)
696 struct stab_info
*sinfo
;
697 struct stab_section_info
*secinfo
;
698 struct stab_excl_list
*e
;
699 bfd_byte
*sym
, *tosym
, *symend
;
700 bfd_size_type
*pstridx
;
702 sinfo
= (struct stab_info
*) *psinfo
;
703 secinfo
= (struct stab_section_info
*) *psecinfo
;
706 return bfd_set_section_contents (output_bfd
, stabsec
->output_section
,
708 (file_ptr
) stabsec
->output_offset
,
711 /* Handle each N_BINCL entry. */
712 for (e
= secinfo
->excls
; e
!= NULL
; e
= e
->next
)
716 BFD_ASSERT (e
->offset
< stabsec
->_raw_size
);
717 excl_sym
= contents
+ e
->offset
;
718 bfd_put_32 (output_bfd
, e
->val
, excl_sym
+ VALOFF
);
719 excl_sym
[TYPEOFF
] = e
->type
;
722 /* Copy over all the stabs symbols, omitting the ones we don't want,
723 and correcting the string indices for those we do want. */
725 symend
= contents
+ stabsec
->_raw_size
;
726 for (sym
= contents
, pstridx
= secinfo
->stridxs
;
728 sym
+= STABSIZE
, ++pstridx
)
730 if (*pstridx
!= (bfd_size_type
) -1)
733 memcpy (tosym
, sym
, STABSIZE
);
734 bfd_put_32 (output_bfd
, *pstridx
, tosym
+ STRDXOFF
);
736 if (sym
[TYPEOFF
] == 0)
738 /* This is the header symbol for the stabs section. We
739 don't really need one, since we have merged all the
740 input stabs sections into one, but we generate one
741 for the benefit of readers which expect to see one. */
742 BFD_ASSERT (sym
== contents
);
743 bfd_put_32 (output_bfd
, _bfd_stringtab_size (sinfo
->strings
),
745 bfd_put_16 (output_bfd
,
746 stabsec
->output_section
->_raw_size
/ STABSIZE
- 1,
754 BFD_ASSERT ((bfd_size_type
) (tosym
- contents
) == stabsec
->_cooked_size
);
756 return bfd_set_section_contents (output_bfd
, stabsec
->output_section
,
757 contents
, (file_ptr
) stabsec
->output_offset
,
758 stabsec
->_cooked_size
);
761 /* Write out the .stabstr section. */
764 _bfd_write_stab_strings (output_bfd
, psinfo
)
768 struct stab_info
*sinfo
;
770 sinfo
= (struct stab_info
*) *psinfo
;
775 if (bfd_is_abs_section (sinfo
->stabstr
->output_section
))
777 /* The section was discarded from the link. */
781 BFD_ASSERT ((sinfo
->stabstr
->output_offset
782 + _bfd_stringtab_size (sinfo
->strings
))
783 <= sinfo
->stabstr
->output_section
->_raw_size
);
785 if (bfd_seek (output_bfd
,
786 (file_ptr
) (sinfo
->stabstr
->output_section
->filepos
787 + sinfo
->stabstr
->output_offset
),
791 if (! _bfd_stringtab_emit (output_bfd
, sinfo
->strings
))
794 /* We no longer need the stabs information. */
795 _bfd_stringtab_free (sinfo
->strings
);
796 bfd_hash_table_free (&sinfo
->includes
.root
);
801 /* Adjust an address in the .stab section. Given OFFSET within
802 STABSEC, this returns the new offset in the adjusted stab section,
803 or -1 if the address refers to a stab which has been removed. */
806 _bfd_stab_section_offset (output_bfd
, psinfo
, stabsec
, psecinfo
, offset
)
807 bfd
*output_bfd ATTRIBUTE_UNUSED
;
808 PTR
*psinfo ATTRIBUTE_UNUSED
;
813 struct stab_section_info
*secinfo
;
815 secinfo
= (struct stab_section_info
*) *psecinfo
;
820 if (offset
>= stabsec
->_raw_size
)
821 return offset
- (stabsec
->_cooked_size
- stabsec
->_raw_size
);
823 if (secinfo
->cumulative_skips
)
827 i
= offset
/ STABSIZE
;
829 if (secinfo
->stridxs
[i
] == (bfd_size_type
) -1)
832 return offset
- secinfo
->cumulative_skips
[i
];