1 /* Object file "section" support for the BFD library.
2 Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
4 Free Software Foundation, Inc.
5 Written by Cygnus Support.
7 This file is part of BFD, the Binary File Descriptor library.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
27 The raw data contained within a BFD is maintained through the
28 section abstraction. A single BFD may have any number of
29 sections. It keeps hold of them by pointing to the first;
30 each one points to the next in the list.
32 Sections are supported in BFD in <<section.c>>.
38 @* section prototypes::
42 Section Input, Section Output, Sections, Sections
46 When a BFD is opened for reading, the section structures are
47 created and attached to the BFD.
49 Each section has a name which describes the section in the
50 outside world---for example, <<a.out>> would contain at least
51 three sections, called <<.text>>, <<.data>> and <<.bss>>.
53 Names need not be unique; for example a COFF file may have several
54 sections named <<.data>>.
56 Sometimes a BFD will contain more than the ``natural'' number of
57 sections. A back end may attach other sections containing
58 constructor data, or an application may add a section (using
59 <<bfd_make_section>>) to the sections attached to an already open
60 BFD. For example, the linker creates an extra section
61 <<COMMON>> for each input file's BFD to hold information about
64 The raw data is not necessarily read in when
65 the section descriptor is created. Some targets may leave the
66 data in place until a <<bfd_get_section_contents>> call is
67 made. Other back ends may read in all the data at once. For
68 example, an S-record file has to be read once to determine the
69 size of the data. An IEEE-695 file doesn't contain raw data in
70 sections, but data and relocation expressions intermixed, so
71 the data area has to be parsed to get out the data and
75 Section Output, typedef asection, Section Input, Sections
80 To write a new object style BFD, the various sections to be
81 written have to be created. They are attached to the BFD in
82 the same way as input sections; data is written to the
83 sections using <<bfd_set_section_contents>>.
85 Any program that creates or combines sections (e.g., the assembler
86 and linker) must use the <<asection>> fields <<output_section>> and
87 <<output_offset>> to indicate the file sections to which each
88 section must be written. (If the section is being created from
89 scratch, <<output_section>> should probably point to the section
90 itself and <<output_offset>> should probably be zero.)
92 The data to be written comes from input sections attached
93 (via <<output_section>> pointers) to
94 the output sections. The output section structure can be
95 considered a filter for the input section: the output section
96 determines the vma of the output data and the name, but the
97 input section determines the offset into the output section of
98 the data to be written.
100 E.g., to create a section "O", starting at 0x100, 0x123 long,
101 containing two subsections, "A" at offset 0x0 (i.e., at vma
102 0x100) and "B" at offset 0x20 (i.e., at vma 0x120) the <<asection>>
103 structures would look like:
108 | output_section -----------> section name "O"
110 | section name "B" | size 0x123
111 | output_offset 0x20 |
113 | output_section --------|
118 The data within a section is stored in a @dfn{link_order}.
119 These are much like the fixups in <<gas>>. The link_order
120 abstraction allows a section to grow and shrink within itself.
122 A link_order knows how big it is, and which is the next
123 link_order and where the raw data for it is; it also points to
124 a list of relocations which apply to it.
126 The link_order is used by the linker to perform relaxing on
127 final code. The compiler creates code which is as big as
128 necessary to make it work without relaxing, and the user can
129 select whether to relax. Sometimes relaxing takes a lot of
130 time. The linker runs around the relocations to see if any
131 are attached to data which can be shrunk, if so it does it on
132 a link_order by link_order basis.
144 typedef asection, section prototypes, Section Output, Sections
148 Here is the section structure:
152 .{* This structure is used for a comdat section, as in PE. A comdat
153 . section is associated with a particular symbol. When the linker
154 . sees a comdat section, it keeps only one of the sections with a
155 . given name and associated with a given symbol. *}
157 .struct bfd_comdat_info
159 . {* The name of the symbol associated with a comdat section. *}
162 . {* The local symbol table index of the symbol associated with a
163 . comdat section. This is only meaningful to the object file format
164 . specific code; it is not an index into the list returned by
165 . bfd_canonicalize_symtab. *}
171 . {* The name of the section; the name isn't a copy, the pointer is
172 . the same as that passed to bfd_make_section. *}
176 . {* A unique sequence number. *}
180 . {* Which section is it; 0..nth. *}
184 . {* The next section in the list belonging to the BFD, or NULL. *}
188 . {* The field flags contains attributes of the section. Some
189 . flags are read in from the object file, and some are
190 . synthesized from other information. *}
194 .#define SEC_NO_FLAGS 0x000
196 . {* Tells the OS to allocate space for this section when loading.
197 . This is clear for a section containing debug information only. *}
198 .#define SEC_ALLOC 0x001
200 . {* Tells the OS to load the section from the file when loading.
201 . This is clear for a .bss section. *}
202 .#define SEC_LOAD 0x002
204 . {* The section contains data still to be relocated, so there is
205 . some relocation information too. *}
206 .#define SEC_RELOC 0x004
208 .#if 0 {* Obsolete ? *}
209 .#define SEC_BALIGN 0x008
212 . {* A signal to the OS that the section contains read only data. *}
213 .#define SEC_READONLY 0x010
215 . {* The section contains code only. *}
216 .#define SEC_CODE 0x020
218 . {* The section contains data only. *}
219 .#define SEC_DATA 0x040
221 . {* The section will reside in ROM. *}
222 .#define SEC_ROM 0x080
224 . {* The section contains constructor information. This section
225 . type is used by the linker to create lists of constructors and
226 . destructors used by <<g++>>. When a back end sees a symbol
227 . which should be used in a constructor list, it creates a new
228 . section for the type of name (e.g., <<__CTOR_LIST__>>), attaches
229 . the symbol to it, and builds a relocation. To build the lists
230 . of constructors, all the linker has to do is catenate all the
231 . sections called <<__CTOR_LIST__>> and relocate the data
232 . contained within - exactly the operations it would peform on
234 .#define SEC_CONSTRUCTOR 0x100
236 . {* The section is a constructor, and should be placed at the
237 . end of the text, data, or bss section(?). *}
238 .#define SEC_CONSTRUCTOR_TEXT 0x1100
239 .#define SEC_CONSTRUCTOR_DATA 0x2100
240 .#define SEC_CONSTRUCTOR_BSS 0x3100
242 . {* The section has contents - a data section could be
243 . <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>; a debug section could be
244 . <<SEC_HAS_CONTENTS>> *}
245 .#define SEC_HAS_CONTENTS 0x200
247 . {* An instruction to the linker to not output the section
248 . even if it has information which would normally be written. *}
249 .#define SEC_NEVER_LOAD 0x400
251 . {* The section is a COFF shared library section. This flag is
252 . only for the linker. If this type of section appears in
253 . the input file, the linker must copy it to the output file
254 . without changing the vma or size. FIXME: Although this
255 . was originally intended to be general, it really is COFF
256 . specific (and the flag was renamed to indicate this). It
257 . might be cleaner to have some more general mechanism to
258 . allow the back end to control what the linker does with
260 .#define SEC_COFF_SHARED_LIBRARY 0x800
262 . {* The section has GOT references. This flag is only for the
263 . linker, and is currently only used by the elf32-hppa back end.
264 . It will be set if global offset table references were detected
265 . in this section, which indicate to the linker that the section
266 . contains PIC code, and must be handled specially when doing a
268 .#define SEC_HAS_GOT_REF 0x4000
270 . {* The section contains common symbols (symbols may be defined
271 . multiple times, the value of a symbol is the amount of
272 . space it requires, and the largest symbol value is the one
273 . used). Most targets have exactly one of these (which we
274 . translate to bfd_com_section_ptr), but ECOFF has two. *}
275 .#define SEC_IS_COMMON 0x8000
277 . {* The section contains only debugging information. For
278 . example, this is set for ELF .debug and .stab sections.
279 . strip tests this flag to see if a section can be
281 .#define SEC_DEBUGGING 0x10000
283 . {* The contents of this section are held in memory pointed to
284 . by the contents field. This is checked by bfd_get_section_contents,
285 . and the data is retrieved from memory if appropriate. *}
286 .#define SEC_IN_MEMORY 0x20000
288 . {* The contents of this section are to be excluded by the
289 . linker for executable and shared objects unless those
290 . objects are to be further relocated. *}
291 .#define SEC_EXCLUDE 0x40000
293 . {* The contents of this section are to be sorted by the
294 . based on the address specified in the associated symbol
296 .#define SEC_SORT_ENTRIES 0x80000
298 . {* When linking, duplicate sections of the same name should be
299 . discarded, rather than being combined into a single section as
300 . is usually done. This is similar to how common symbols are
301 . handled. See SEC_LINK_DUPLICATES below. *}
302 .#define SEC_LINK_ONCE 0x100000
304 . {* If SEC_LINK_ONCE is set, this bitfield describes how the linker
305 . should handle duplicate sections. *}
306 .#define SEC_LINK_DUPLICATES 0x600000
308 . {* This value for SEC_LINK_DUPLICATES means that duplicate
309 . sections with the same name should simply be discarded. *}
310 .#define SEC_LINK_DUPLICATES_DISCARD 0x0
312 . {* This value for SEC_LINK_DUPLICATES means that the linker
313 . should warn if there are any duplicate sections, although
314 . it should still only link one copy. *}
315 .#define SEC_LINK_DUPLICATES_ONE_ONLY 0x200000
317 . {* This value for SEC_LINK_DUPLICATES means that the linker
318 . should warn if any duplicate sections are a different size. *}
319 .#define SEC_LINK_DUPLICATES_SAME_SIZE 0x400000
321 . {* This value for SEC_LINK_DUPLICATES means that the linker
322 . should warn if any duplicate sections contain different
324 .#define SEC_LINK_DUPLICATES_SAME_CONTENTS 0x600000
326 . {* This section was created by the linker as part of dynamic
327 . relocation or other arcane processing. It is skipped when
328 . going through the first-pass output, trusting that someone
329 . else up the line will take care of it later. *}
330 .#define SEC_LINKER_CREATED 0x800000
332 . {* This section should not be subject to garbage collection. *}
333 .#define SEC_KEEP 0x1000000
335 . {* This section contains "short" data, and should be placed
337 .#define SEC_SMALL_DATA 0x2000000
339 . {* This section contains data which may be shared with other
340 . executables or shared objects. *}
341 .#define SEC_SHARED 0x4000000
343 . {* When a section with this flag is being linked, then if the size of
344 . the input section is less than a page, it should not cross a page
345 . boundary. If the size of the input section is one page or more, it
346 . should be aligned on a page boundary. *}
347 .#define SEC_BLOCK 0x8000000
349 . {* Conditionally link this section; do not link if there are no
350 . references found to any symbol in the section. *}
351 .#define SEC_CLINK 0x10000000
353 . {* End of section flags. *}
355 . {* Some internal packed boolean fields. *}
357 . {* See the vma field. *}
358 . unsigned int user_set_vma : 1;
360 . {* Whether relocations have been processed. *}
361 . unsigned int reloc_done : 1;
363 . {* A mark flag used by some of the linker backends. *}
364 . unsigned int linker_mark : 1;
366 . {* A mark flag used by some linker backends for garbage collection. *}
367 . unsigned int gc_mark : 1;
369 . {* Used by the ELF code to mark sections which have been allocated to segments. *}
370 . unsigned int segment_mark : 1;
372 . {* End of internal packed boolean fields. *}
374 . {* The virtual memory address of the section - where it will be
375 . at run time. The symbols are relocated against this. The
376 . user_set_vma flag is maintained by bfd; if it's not set, the
377 . backend can assign addresses (for example, in <<a.out>>, where
378 . the default address for <<.data>> is dependent on the specific
379 . target and various flags). *}
383 . {* The load address of the section - where it would be in a
384 . rom image; really only used for writing section header
389 . {* The size of the section in octets, as it will be output.
390 . Contains a value even if the section has no contents (e.g., the
391 . size of <<.bss>>). This will be filled in after relocation. *}
393 . bfd_size_type _cooked_size;
395 . {* The original size on disk of the section, in octets. Normally this
396 . value is the same as the size, but if some relaxing has
397 . been done, then this value will be bigger. *}
399 . bfd_size_type _raw_size;
401 . {* If this section is going to be output, then this value is the
402 . offset in *bytes* into the output section of the first byte in the
403 . input section (byte ==> smallest addressable unit on the
404 . target). In most cases, if this was going to start at the
405 . 100th octet (8-bit quantity) in the output section, this value
406 . would be 100. However, if the target byte size is 16 bits
407 . (bfd_octets_per_byte is "2"), this value would be 50. *}
409 . bfd_vma output_offset;
411 . {* The output section through which to map on output. *}
413 . struct sec *output_section;
415 . {* The alignment requirement of the section, as an exponent of 2 -
416 . e.g., 3 aligns to 2^3 (or 8). *}
418 . unsigned int alignment_power;
420 . {* If an input section, a pointer to a vector of relocation
421 . records for the data in this section. *}
423 . struct reloc_cache_entry *relocation;
425 . {* If an output section, a pointer to a vector of pointers to
426 . relocation records for the data in this section. *}
428 . struct reloc_cache_entry **orelocation;
430 . {* The number of relocation records in one of the above *}
432 . unsigned reloc_count;
434 . {* Information below is back end specific - and not always used
437 . {* File position of section data. *}
441 . {* File position of relocation info. *}
443 . file_ptr rel_filepos;
445 . {* File position of line data. *}
447 . file_ptr line_filepos;
449 . {* Pointer to data for applications. *}
453 . {* If the SEC_IN_MEMORY flag is set, this points to the actual
455 . unsigned char *contents;
457 . {* Attached line number information. *}
461 . {* Number of line number records. *}
463 . unsigned int lineno_count;
465 . {* Optional information about a COMDAT entry; NULL if not COMDAT. *}
467 . struct bfd_comdat_info *comdat;
469 . {* Points to the kept section if this section is a link-once section,
470 . and is discarded. *}
471 . struct sec *kept_section;
473 . {* When a section is being output, this value changes as more
474 . linenumbers are written out. *}
476 . file_ptr moving_line_filepos;
478 . {* What the section number is in the target world. *}
484 . {* If this is a constructor section then here is a list of the
485 . relocations created to relocate items within it. *}
487 . struct relent_chain *constructor_chain;
489 . {* The BFD which owns the section. *}
493 . {* A symbol which points at this section only *}
494 . struct symbol_cache_entry *symbol;
495 . struct symbol_cache_entry **symbol_ptr_ptr;
497 . struct bfd_link_order *link_order_head;
498 . struct bfd_link_order *link_order_tail;
501 .{* These sections are global, and are managed by BFD. The application
502 . and target back end are not permitted to change the values in
503 . these sections. New code should use the section_ptr macros rather
504 . than referring directly to the const sections. The const sections
505 . may eventually vanish. *}
506 .#define BFD_ABS_SECTION_NAME "*ABS*"
507 .#define BFD_UND_SECTION_NAME "*UND*"
508 .#define BFD_COM_SECTION_NAME "*COM*"
509 .#define BFD_IND_SECTION_NAME "*IND*"
511 .{* the absolute section *}
512 .extern const asection bfd_abs_section;
513 .#define bfd_abs_section_ptr ((asection *) &bfd_abs_section)
514 .#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr)
515 .{* Pointer to the undefined section *}
516 .extern const asection bfd_und_section;
517 .#define bfd_und_section_ptr ((asection *) &bfd_und_section)
518 .#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr)
519 .{* Pointer to the common section *}
520 .extern const asection bfd_com_section;
521 .#define bfd_com_section_ptr ((asection *) &bfd_com_section)
522 .{* Pointer to the indirect section *}
523 .extern const asection bfd_ind_section;
524 .#define bfd_ind_section_ptr ((asection *) &bfd_ind_section)
525 .#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr)
527 .extern const struct symbol_cache_entry * const bfd_abs_symbol;
528 .extern const struct symbol_cache_entry * const bfd_com_symbol;
529 .extern const struct symbol_cache_entry * const bfd_und_symbol;
530 .extern const struct symbol_cache_entry * const bfd_ind_symbol;
531 .#define bfd_get_section_size_before_reloc(section) \
532 . ((section)->reloc_done ? (abort (), (bfd_size_type) 1) \
533 . : (section)->_raw_size)
534 .#define bfd_get_section_size_after_reloc(section) \
535 . ((section)->reloc_done ? (section)->_cooked_size \
536 . : (abort (), (bfd_size_type) 1))
539 /* We use a macro to initialize the static asymbol structures because
540 traditional C does not permit us to initialize a union member while
541 gcc warns if we don't initialize it. */
542 /* the_bfd, name, value, attr, section [, udata] */
544 #define GLOBAL_SYM_INIT(NAME, SECTION) \
545 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION, { 0 }}
547 #define GLOBAL_SYM_INIT(NAME, SECTION) \
548 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION }
551 /* These symbols are global, not specific to any BFD. Therefore, anything
552 that tries to change them is broken, and should be repaired. */
554 static const asymbol global_syms
[] =
556 GLOBAL_SYM_INIT (BFD_COM_SECTION_NAME
, &bfd_com_section
),
557 GLOBAL_SYM_INIT (BFD_UND_SECTION_NAME
, &bfd_und_section
),
558 GLOBAL_SYM_INIT (BFD_ABS_SECTION_NAME
, &bfd_abs_section
),
559 GLOBAL_SYM_INIT (BFD_IND_SECTION_NAME
, &bfd_ind_section
)
562 #define STD_SECTION(SEC, FLAGS, SYM, NAME, IDX) \
563 const asymbol * const SYM = (asymbol *) &global_syms[IDX]; \
564 const asection SEC = \
565 /* name, id, index, next, flags, user_set_vma, reloc_done, */ \
566 { NAME, IDX, 0, NULL, FLAGS, 0, 0, \
568 /* linker_mark, gc_mark, segment_mark, vma, lma, _cooked_size, */ \
571 /* _raw_size, output_offset, output_section, alignment_power, */ \
572 0, 0, (struct sec *) &SEC, 0, \
574 /* relocation, orelocation, reloc_count, filepos, rel_filepos, */ \
575 NULL, NULL, 0, 0, 0, \
577 /* line_filepos, userdata, contents, lineno, lineno_count, */ \
578 0, NULL, NULL, NULL, 0, \
580 /* comdat, kept_section, moving_line_filepos, target_index, */ \
583 /* used_by_bfd, constructor_chain, owner, */ \
587 (struct symbol_cache_entry *) &global_syms[IDX], \
589 /* symbol_ptr_ptr, */ \
590 (struct symbol_cache_entry **) &SYM, \
592 /* link_order_head, link_order_tail */ \
596 STD_SECTION (bfd_com_section
, SEC_IS_COMMON
, bfd_com_symbol
,
597 BFD_COM_SECTION_NAME
, 0);
598 STD_SECTION (bfd_und_section
, 0, bfd_und_symbol
, BFD_UND_SECTION_NAME
, 1);
599 STD_SECTION (bfd_abs_section
, 0, bfd_abs_symbol
, BFD_ABS_SECTION_NAME
, 2);
600 STD_SECTION (bfd_ind_section
, 0, bfd_ind_symbol
, BFD_IND_SECTION_NAME
, 3);
606 section prototypes, , typedef asection, Sections
610 These are the functions exported by the section handling part of BFD.
615 bfd_get_section_by_name
618 asection *bfd_get_section_by_name(bfd *abfd, const char *name);
621 Run through @var{abfd} and return the one of the
622 <<asection>>s whose name matches @var{name}, otherwise <<NULL>>.
623 @xref{Sections}, for more information.
625 This should only be used in special cases; the normal way to process
626 all sections of a given name is to use <<bfd_map_over_sections>> and
627 <<strcmp>> on the name (or better yet, base it on the section flags
628 or something else) for each section.
632 bfd_get_section_by_name (abfd
, name
)
638 for (sect
= abfd
->sections
; sect
!= NULL
; sect
= sect
->next
)
639 if (!strcmp (sect
->name
, name
))
646 bfd_get_unique_section_name
649 char *bfd_get_unique_section_name(bfd *abfd,
654 Invent a section name that is unique in @var{abfd} by tacking
655 a dot and a digit suffix onto the original @var{templat}. If
656 @var{count} is non-NULL, then it specifies the first number
657 tried as a suffix to generate a unique name. The value
658 pointed to by @var{count} will be incremented in this case.
662 bfd_get_unique_section_name (abfd
, templat
, count
)
671 len
= strlen (templat
);
672 sname
= bfd_malloc (len
+ 8);
675 strcpy (sname
, templat
);
682 /* If we have a million sections, something is badly wrong. */
685 sprintf (sname
+ len
, ".%d", num
++);
687 while (bfd_get_section_by_name (abfd
, sname
) != NULL
);
696 bfd_make_section_old_way
699 asection *bfd_make_section_old_way(bfd *abfd, const char *name);
702 Create a new empty section called @var{name}
703 and attach it to the end of the chain of sections for the
704 BFD @var{abfd}. An attempt to create a section with a name which
705 is already in use returns its pointer without changing the
708 It has the funny name since this is the way it used to be
709 before it was rewritten....
712 o <<bfd_error_invalid_operation>> -
713 If output has already started for this BFD.
714 o <<bfd_error_no_memory>> -
715 If memory allocation fails.
720 bfd_make_section_old_way (abfd
, name
)
724 asection
*sec
= bfd_get_section_by_name (abfd
, name
);
725 if (sec
== (asection
*) NULL
)
727 sec
= bfd_make_section (abfd
, name
);
734 bfd_make_section_anyway
737 asection *bfd_make_section_anyway(bfd *abfd, const char *name);
740 Create a new empty section called @var{name} and attach it to the end of
741 the chain of sections for @var{abfd}. Create a new section even if there
742 is already a section with that name.
744 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
745 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
746 o <<bfd_error_no_memory>> - If memory allocation fails.
750 bfd_make_section_anyway (abfd
, name
)
754 static int section_id
= 0x10; /* id 0 to 3 used by STD_SECTION. */
756 asection
**prev
= &abfd
->sections
;
757 asection
*sect
= abfd
->sections
;
759 if (abfd
->output_has_begun
)
761 bfd_set_error (bfd_error_invalid_operation
);
771 newsect
= (asection
*) bfd_zalloc (abfd
, sizeof (asection
));
775 newsect
->name
= name
;
776 newsect
->id
= section_id
++;
777 newsect
->index
= abfd
->section_count
++;
778 newsect
->flags
= SEC_NO_FLAGS
;
780 newsect
->userdata
= NULL
;
781 newsect
->contents
= NULL
;
782 newsect
->next
= (asection
*) NULL
;
783 newsect
->relocation
= (arelent
*) NULL
;
784 newsect
->reloc_count
= 0;
785 newsect
->line_filepos
= 0;
786 newsect
->owner
= abfd
;
787 newsect
->comdat
= NULL
;
788 newsect
->kept_section
= NULL
;
790 /* Create a symbol whos only job is to point to this section. This is
791 useful for things like relocs which are relative to the base of a
793 newsect
->symbol
= bfd_make_empty_symbol (abfd
);
794 if (newsect
->symbol
== NULL
)
796 bfd_release (abfd
, newsect
);
799 newsect
->symbol
->name
= name
;
800 newsect
->symbol
->value
= 0;
801 newsect
->symbol
->section
= newsect
;
802 newsect
->symbol
->flags
= BSF_SECTION_SYM
;
804 newsect
->symbol_ptr_ptr
= &newsect
->symbol
;
806 if (BFD_SEND (abfd
, _new_section_hook
, (abfd
, newsect
)) != true)
808 bfd_release (abfd
, newsect
);
821 asection *bfd_make_section(bfd *, const char *name);
824 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
825 bfd_set_error ()) without changing the section chain if there is already a
826 section named @var{name}. If there is an error, return <<NULL>> and set
831 bfd_make_section (abfd
, name
)
835 asection
*sect
= abfd
->sections
;
837 if (strcmp (name
, BFD_ABS_SECTION_NAME
) == 0)
839 return bfd_abs_section_ptr
;
841 if (strcmp (name
, BFD_COM_SECTION_NAME
) == 0)
843 return bfd_com_section_ptr
;
845 if (strcmp (name
, BFD_UND_SECTION_NAME
) == 0)
847 return bfd_und_section_ptr
;
850 if (strcmp (name
, BFD_IND_SECTION_NAME
) == 0)
852 return bfd_ind_section_ptr
;
857 if (!strcmp (sect
->name
, name
))
862 /* The name is not already used; go ahead and make a new section. */
863 return bfd_make_section_anyway (abfd
, name
);
868 bfd_set_section_flags
871 boolean bfd_set_section_flags(bfd *abfd, asection *sec, flagword flags);
874 Set the attributes of the section @var{sec} in the BFD
875 @var{abfd} to the value @var{flags}. Return <<true>> on success,
876 <<false>> on error. Possible error returns are:
878 o <<bfd_error_invalid_operation>> -
879 The section cannot have one or more of the attributes
880 requested. For example, a .bss section in <<a.out>> may not
881 have the <<SEC_HAS_CONTENTS>> field set.
887 bfd_set_section_flags (abfd
, section
, flags
)
888 bfd
*abfd ATTRIBUTE_UNUSED
;
893 /* If you try to copy a text section from an input file (where it
894 has the SEC_CODE flag set) to an output file, this loses big if
895 the bfd_applicable_section_flags (abfd) doesn't have the SEC_CODE
896 set - which it doesn't, at least not for a.out. FIXME */
898 if ((flags
& bfd_applicable_section_flags (abfd
)) != flags
)
900 bfd_set_error (bfd_error_invalid_operation
);
905 section
->flags
= flags
;
911 bfd_map_over_sections
914 void bfd_map_over_sections(bfd *abfd,
915 void (*func) (bfd *abfd,
921 Call the provided function @var{func} for each section
922 attached to the BFD @var{abfd}, passing @var{obj} as an
923 argument. The function will be called as if by
925 | func(abfd, the_section, obj);
927 This is the prefered method for iterating over sections; an
928 alternative would be to use a loop:
931 | for (p = abfd->sections; p != NULL; p = p->next)
938 bfd_map_over_sections (abfd
, operation
, user_storage
)
940 void (*operation
) PARAMS ((bfd
* abfd
, asection
* sect
, PTR obj
));
946 for (sect
= abfd
->sections
; sect
!= NULL
; i
++, sect
= sect
->next
)
947 (*operation
) (abfd
, sect
, user_storage
);
949 if (i
!= abfd
->section_count
) /* Debugging */
958 boolean bfd_set_section_size(bfd *abfd, asection *sec, bfd_size_type val);
961 Set @var{sec} to the size @var{val}. If the operation is
962 ok, then <<true>> is returned, else <<false>>.
964 Possible error returns:
965 o <<bfd_error_invalid_operation>> -
966 Writing has started to the BFD, so setting the size is invalid.
971 bfd_set_section_size (abfd
, ptr
, val
)
976 /* Once you've started writing to any section you cannot create or change
977 the size of any others. */
979 if (abfd
->output_has_begun
)
981 bfd_set_error (bfd_error_invalid_operation
);
985 ptr
->_cooked_size
= val
;
986 ptr
->_raw_size
= val
;
993 bfd_set_section_contents
996 boolean bfd_set_section_contents
1001 bfd_size_type count);
1004 Sets the contents of the section @var{section} in BFD
1005 @var{abfd} to the data starting in memory at @var{data}. The
1006 data is written to the output section starting at offset
1007 @var{offset} for @var{count} octets.
1009 Normally <<true>> is returned, else <<false>>. Possible error
1011 o <<bfd_error_no_contents>> -
1012 The output section does not have the <<SEC_HAS_CONTENTS>>
1013 attribute, so nothing can be written to it.
1016 This routine is front end to the back end function
1017 <<_bfd_set_section_contents>>.
1021 #define bfd_get_section_size_now(abfd,sec) \
1023 ? bfd_get_section_size_after_reloc (sec) \
1024 : bfd_get_section_size_before_reloc (sec))
1027 bfd_set_section_contents (abfd
, section
, location
, offset
, count
)
1032 bfd_size_type count
;
1036 if (!(bfd_get_section_flags (abfd
, section
) & SEC_HAS_CONTENTS
))
1038 bfd_set_error (bfd_error_no_contents
);
1045 bfd_set_error (bfd_error_bad_value
);
1048 sz
= bfd_get_section_size_now (abfd
, section
);
1049 if ((bfd_size_type
) offset
> sz
1051 || offset
+ count
> sz
)
1054 switch (abfd
->direction
)
1056 case read_direction
:
1058 bfd_set_error (bfd_error_invalid_operation
);
1061 case write_direction
:
1064 case both_direction
:
1065 /* File is opened for update. `output_has_begun' some time ago when
1066 the file was created. Do not recompute sections sizes or alignments
1067 in _bfd_set_section_content. */
1068 abfd
->output_has_begun
= true;
1072 /* Record a copy of the data in memory if desired. */
1073 if (section
->contents
1074 && location
!= section
->contents
+ offset
)
1075 memcpy (section
->contents
+ offset
, location
, count
);
1077 if (BFD_SEND (abfd
, _bfd_set_section_contents
,
1078 (abfd
, section
, location
, offset
, count
)))
1080 abfd
->output_has_begun
= true;
1089 bfd_get_section_contents
1092 boolean bfd_get_section_contents
1093 (bfd *abfd, asection *section, PTR location,
1094 file_ptr offset, bfd_size_type count);
1097 Read data from @var{section} in BFD @var{abfd}
1098 into memory starting at @var{location}. The data is read at an
1099 offset of @var{offset} from the start of the input section,
1100 and is read for @var{count} bytes.
1102 If the contents of a constructor with the <<SEC_CONSTRUCTOR>>
1103 flag set are requested or if the section does not have the
1104 <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled
1105 with zeroes. If no errors occur, <<true>> is returned, else
1110 bfd_get_section_contents (abfd
, section
, location
, offset
, count
)
1115 bfd_size_type count
;
1119 if (section
->flags
& SEC_CONSTRUCTOR
)
1121 memset (location
, 0, (unsigned) count
);
1128 bfd_set_error (bfd_error_bad_value
);
1131 /* Even if reloc_done is true, this function reads unrelocated
1132 contents, so we want the raw size. */
1133 sz
= section
->_raw_size
;
1134 if ((bfd_size_type
) offset
> sz
|| count
> sz
|| offset
+ count
> sz
)
1141 if ((section
->flags
& SEC_HAS_CONTENTS
) == 0)
1143 memset (location
, 0, (unsigned) count
);
1147 if ((section
->flags
& SEC_IN_MEMORY
) != 0)
1149 memcpy (location
, section
->contents
+ offset
, (size_t) count
);
1153 return BFD_SEND (abfd
, _bfd_get_section_contents
,
1154 (abfd
, section
, location
, offset
, count
));
1159 bfd_copy_private_section_data
1162 boolean bfd_copy_private_section_data(bfd *ibfd, asection *isec, bfd *obfd, asection *osec);
1165 Copy private section information from @var{isec} in the BFD
1166 @var{ibfd} to the section @var{osec} in the BFD @var{obfd}.
1167 Return <<true>> on success, <<false>> on error. Possible error
1170 o <<bfd_error_no_memory>> -
1171 Not enough memory exists to create private data for @var{osec}.
1173 .#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \
1174 . BFD_SEND (obfd, _bfd_copy_private_section_data, \
1175 . (ibfd, isection, obfd, osection))
1180 _bfd_strip_section_from_output
1183 void _bfd_strip_section_from_output
1184 (struct bfd_link_info *info, asection *section);
1187 Remove @var{section} from the output. If the output section
1188 becomes empty, remove it from the output bfd. @var{info} may
1189 be NULL; if it is not, it is used to decide whether the output
1193 _bfd_strip_section_from_output (info
, s
)
1194 struct bfd_link_info
*info
;
1197 asection
**spp
, *os
;
1198 struct bfd_link_order
*p
, *pp
;
1201 /* Excise the input section from the link order.
1203 FIXME: For all calls that I can see to this function, the link
1204 orders have not yet been set up. So why are we checking them? --
1206 os
= s
->output_section
;
1207 for (p
= os
->link_order_head
, pp
= NULL
; p
!= NULL
; pp
= p
, p
= p
->next
)
1208 if (p
->type
== bfd_indirect_link_order
1209 && p
->u
.indirect
.section
== s
)
1214 os
->link_order_head
= p
->next
;
1216 os
->link_order_tail
= pp
;
1220 keep_os
= os
->link_order_head
!= NULL
;
1222 if (! keep_os
&& info
!= NULL
)
1225 for (abfd
= info
->input_bfds
; abfd
!= NULL
; abfd
= abfd
->link_next
)
1228 for (is
= abfd
->sections
; is
!= NULL
; is
= is
->next
)
1230 if (is
!= s
&& is
->output_section
== os
)
1240 /* If the output section is empty, remove it too. Careful about sections
1241 that have been discarded in the link script -- they are mapped to
1242 bfd_abs_section, which has no owner. */
1243 if (!keep_os
&& os
->owner
!= NULL
)
1245 for (spp
= &os
->owner
->sections
; *spp
; spp
= &(*spp
)->next
)
1249 os
->owner
->section_count
--;