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 . {* ELF reserves 4 processor specific bits and 8 operating system
209 . specific bits in sh_flags; at present we can get away with just
210 . one in communicating between the assembler and BFD, but this
211 . isn't a good long-term solution. *}
212 .#define SEC_ARCH_BIT_0 0x008
214 . {* A signal to the OS that the section contains read only data. *}
215 .#define SEC_READONLY 0x010
217 . {* The section contains code only. *}
218 .#define SEC_CODE 0x020
220 . {* The section contains data only. *}
221 .#define SEC_DATA 0x040
223 . {* The section will reside in ROM. *}
224 .#define SEC_ROM 0x080
226 . {* The section contains constructor information. This section
227 . type is used by the linker to create lists of constructors and
228 . destructors used by <<g++>>. When a back end sees a symbol
229 . which should be used in a constructor list, it creates a new
230 . section for the type of name (e.g., <<__CTOR_LIST__>>), attaches
231 . the symbol to it, and builds a relocation. To build the lists
232 . of constructors, all the linker has to do is catenate all the
233 . sections called <<__CTOR_LIST__>> and relocate the data
234 . contained within - exactly the operations it would peform on
236 .#define SEC_CONSTRUCTOR 0x100
238 . {* The section is a constructor, and should be placed at the
239 . end of the text, data, or bss section(?). *}
240 .#define SEC_CONSTRUCTOR_TEXT 0x1100
241 .#define SEC_CONSTRUCTOR_DATA 0x2100
242 .#define SEC_CONSTRUCTOR_BSS 0x3100
244 . {* The section has contents - a data section could be
245 . <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>; a debug section could be
246 . <<SEC_HAS_CONTENTS>> *}
247 .#define SEC_HAS_CONTENTS 0x200
249 . {* An instruction to the linker to not output the section
250 . even if it has information which would normally be written. *}
251 .#define SEC_NEVER_LOAD 0x400
253 . {* The section is a COFF shared library section. This flag is
254 . only for the linker. If this type of section appears in
255 . the input file, the linker must copy it to the output file
256 . without changing the vma or size. FIXME: Although this
257 . was originally intended to be general, it really is COFF
258 . specific (and the flag was renamed to indicate this). It
259 . might be cleaner to have some more general mechanism to
260 . allow the back end to control what the linker does with
262 .#define SEC_COFF_SHARED_LIBRARY 0x800
264 . {* The section has GOT references. This flag is only for the
265 . linker, and is currently only used by the elf32-hppa back end.
266 . It will be set if global offset table references were detected
267 . in this section, which indicate to the linker that the section
268 . contains PIC code, and must be handled specially when doing a
270 .#define SEC_HAS_GOT_REF 0x4000
272 . {* The section contains common symbols (symbols may be defined
273 . multiple times, the value of a symbol is the amount of
274 . space it requires, and the largest symbol value is the one
275 . used). Most targets have exactly one of these (which we
276 . translate to bfd_com_section_ptr), but ECOFF has two. *}
277 .#define SEC_IS_COMMON 0x8000
279 . {* The section contains only debugging information. For
280 . example, this is set for ELF .debug and .stab sections.
281 . strip tests this flag to see if a section can be
283 .#define SEC_DEBUGGING 0x10000
285 . {* The contents of this section are held in memory pointed to
286 . by the contents field. This is checked by bfd_get_section_contents,
287 . and the data is retrieved from memory if appropriate. *}
288 .#define SEC_IN_MEMORY 0x20000
290 . {* The contents of this section are to be excluded by the
291 . linker for executable and shared objects unless those
292 . objects are to be further relocated. *}
293 .#define SEC_EXCLUDE 0x40000
295 . {* The contents of this section are to be sorted by the
296 . based on the address specified in the associated symbol
298 .#define SEC_SORT_ENTRIES 0x80000
300 . {* When linking, duplicate sections of the same name should be
301 . discarded, rather than being combined into a single section as
302 . is usually done. This is similar to how common symbols are
303 . handled. See SEC_LINK_DUPLICATES below. *}
304 .#define SEC_LINK_ONCE 0x100000
306 . {* If SEC_LINK_ONCE is set, this bitfield describes how the linker
307 . should handle duplicate sections. *}
308 .#define SEC_LINK_DUPLICATES 0x600000
310 . {* This value for SEC_LINK_DUPLICATES means that duplicate
311 . sections with the same name should simply be discarded. *}
312 .#define SEC_LINK_DUPLICATES_DISCARD 0x0
314 . {* This value for SEC_LINK_DUPLICATES means that the linker
315 . should warn if there are any duplicate sections, although
316 . it should still only link one copy. *}
317 .#define SEC_LINK_DUPLICATES_ONE_ONLY 0x200000
319 . {* This value for SEC_LINK_DUPLICATES means that the linker
320 . should warn if any duplicate sections are a different size. *}
321 .#define SEC_LINK_DUPLICATES_SAME_SIZE 0x400000
323 . {* This value for SEC_LINK_DUPLICATES means that the linker
324 . should warn if any duplicate sections contain different
326 .#define SEC_LINK_DUPLICATES_SAME_CONTENTS 0x600000
328 . {* This section was created by the linker as part of dynamic
329 . relocation or other arcane processing. It is skipped when
330 . going through the first-pass output, trusting that someone
331 . else up the line will take care of it later. *}
332 .#define SEC_LINKER_CREATED 0x800000
334 . {* This section should not be subject to garbage collection. *}
335 .#define SEC_KEEP 0x1000000
337 . {* This section contains "short" data, and should be placed
339 .#define SEC_SMALL_DATA 0x2000000
341 . {* This section contains data which may be shared with other
342 . executables or shared objects. *}
343 .#define SEC_SHARED 0x4000000
345 . {* When a section with this flag is being linked, then if the size of
346 . the input section is less than a page, it should not cross a page
347 . boundary. If the size of the input section is one page or more, it
348 . should be aligned on a page boundary. *}
349 .#define SEC_BLOCK 0x8000000
351 . {* Conditionally link this section; do not link if there are no
352 . references found to any symbol in the section. *}
353 .#define SEC_CLINK 0x10000000
355 . {* Attempt to merge identical entities in the section.
356 . Entity size is given in the entsize field. *}
357 .#define SEC_MERGE 0x20000000
359 . {* If given with SEC_MERGE, entities to merge are zero terminated
360 . strings where entsize specifies character size instead of fixed
362 .#define SEC_STRINGS 0x40000000
364 . {* End of section flags. *}
366 . {* Some internal packed boolean fields. *}
368 . {* See the vma field. *}
369 . unsigned int user_set_vma : 1;
371 . {* Whether relocations have been processed. *}
372 . unsigned int reloc_done : 1;
374 . {* A mark flag used by some of the linker backends. *}
375 . unsigned int linker_mark : 1;
377 . {* Another mark flag used by some of the linker backends. Set for
378 . output sections that have a input section. *}
379 . unsigned int linker_has_input : 1;
381 . {* A mark flag used by some linker backends for garbage collection. *}
382 . unsigned int gc_mark : 1;
384 . {* Used by the ELF code to mark sections which have been allocated to segments. *}
385 . unsigned int segment_mark : 1;
387 . {* End of internal packed boolean fields. *}
389 . {* The virtual memory address of the section - where it will be
390 . at run time. The symbols are relocated against this. The
391 . user_set_vma flag is maintained by bfd; if it's not set, the
392 . backend can assign addresses (for example, in <<a.out>>, where
393 . the default address for <<.data>> is dependent on the specific
394 . target and various flags). *}
398 . {* The load address of the section - where it would be in a
399 . rom image; really only used for writing section header
404 . {* The size of the section in octets, as it will be output.
405 . Contains a value even if the section has no contents (e.g., the
406 . size of <<.bss>>). This will be filled in after relocation. *}
408 . bfd_size_type _cooked_size;
410 . {* The original size on disk of the section, in octets. Normally this
411 . value is the same as the size, but if some relaxing has
412 . been done, then this value will be bigger. *}
414 . bfd_size_type _raw_size;
416 . {* If this section is going to be output, then this value is the
417 . offset in *bytes* into the output section of the first byte in the
418 . input section (byte ==> smallest addressable unit on the
419 . target). In most cases, if this was going to start at the
420 . 100th octet (8-bit quantity) in the output section, this value
421 . would be 100. However, if the target byte size is 16 bits
422 . (bfd_octets_per_byte is "2"), this value would be 50. *}
424 . bfd_vma output_offset;
426 . {* The output section through which to map on output. *}
428 . struct sec *output_section;
430 . {* The alignment requirement of the section, as an exponent of 2 -
431 . e.g., 3 aligns to 2^3 (or 8). *}
433 . unsigned int alignment_power;
435 . {* If an input section, a pointer to a vector of relocation
436 . records for the data in this section. *}
438 . struct reloc_cache_entry *relocation;
440 . {* If an output section, a pointer to a vector of pointers to
441 . relocation records for the data in this section. *}
443 . struct reloc_cache_entry **orelocation;
445 . {* The number of relocation records in one of the above *}
447 . unsigned reloc_count;
449 . {* Information below is back end specific - and not always used
452 . {* File position of section data. *}
456 . {* File position of relocation info. *}
458 . file_ptr rel_filepos;
460 . {* File position of line data. *}
462 . file_ptr line_filepos;
464 . {* Pointer to data for applications. *}
468 . {* If the SEC_IN_MEMORY flag is set, this points to the actual
470 . unsigned char *contents;
472 . {* Attached line number information. *}
476 . {* Number of line number records. *}
478 . unsigned int lineno_count;
480 . {* Entity size for merging purposes. *}
482 . unsigned int entsize;
484 . {* Optional information about a COMDAT entry; NULL if not COMDAT. *}
486 . struct bfd_comdat_info *comdat;
488 . {* When a section is being output, this value changes as more
489 . linenumbers are written out. *}
491 . file_ptr moving_line_filepos;
493 . {* What the section number is in the target world. *}
499 . {* If this is a constructor section then here is a list of the
500 . relocations created to relocate items within it. *}
502 . struct relent_chain *constructor_chain;
504 . {* The BFD which owns the section. *}
508 . {* A symbol which points at this section only *}
509 . struct symbol_cache_entry *symbol;
510 . struct symbol_cache_entry **symbol_ptr_ptr;
512 . struct bfd_link_order *link_order_head;
513 . struct bfd_link_order *link_order_tail;
516 .{* These sections are global, and are managed by BFD. The application
517 . and target back end are not permitted to change the values in
518 . these sections. New code should use the section_ptr macros rather
519 . than referring directly to the const sections. The const sections
520 . may eventually vanish. *}
521 .#define BFD_ABS_SECTION_NAME "*ABS*"
522 .#define BFD_UND_SECTION_NAME "*UND*"
523 .#define BFD_COM_SECTION_NAME "*COM*"
524 .#define BFD_IND_SECTION_NAME "*IND*"
526 .{* the absolute section *}
527 .extern const asection bfd_abs_section;
528 .#define bfd_abs_section_ptr ((asection *) &bfd_abs_section)
529 .#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr)
530 .{* Pointer to the undefined section *}
531 .extern const asection bfd_und_section;
532 .#define bfd_und_section_ptr ((asection *) &bfd_und_section)
533 .#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr)
534 .{* Pointer to the common section *}
535 .extern const asection bfd_com_section;
536 .#define bfd_com_section_ptr ((asection *) &bfd_com_section)
537 .{* Pointer to the indirect section *}
538 .extern const asection bfd_ind_section;
539 .#define bfd_ind_section_ptr ((asection *) &bfd_ind_section)
540 .#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr)
542 .extern const struct symbol_cache_entry * const bfd_abs_symbol;
543 .extern const struct symbol_cache_entry * const bfd_com_symbol;
544 .extern const struct symbol_cache_entry * const bfd_und_symbol;
545 .extern const struct symbol_cache_entry * const bfd_ind_symbol;
546 .#define bfd_get_section_size_before_reloc(section) \
547 . ((section)->reloc_done ? (abort (), (bfd_size_type) 1) \
548 . : (section)->_raw_size)
549 .#define bfd_get_section_size_after_reloc(section) \
550 . ((section)->reloc_done ? (section)->_cooked_size \
551 . : (abort (), (bfd_size_type) 1))
554 /* We use a macro to initialize the static asymbol structures because
555 traditional C does not permit us to initialize a union member while
556 gcc warns if we don't initialize it. */
557 /* the_bfd, name, value, attr, section [, udata] */
559 #define GLOBAL_SYM_INIT(NAME, SECTION) \
560 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION, { 0 }}
562 #define GLOBAL_SYM_INIT(NAME, SECTION) \
563 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION }
566 /* These symbols are global, not specific to any BFD. Therefore, anything
567 that tries to change them is broken, and should be repaired. */
569 static const asymbol global_syms[] =
571 GLOBAL_SYM_INIT (BFD_COM_SECTION_NAME, &bfd_com_section),
572 GLOBAL_SYM_INIT (BFD_UND_SECTION_NAME, &bfd_und_section),
573 GLOBAL_SYM_INIT (BFD_ABS_SECTION_NAME, &bfd_abs_section),
574 GLOBAL_SYM_INIT (BFD_IND_SECTION_NAME, &bfd_ind_section)
577 #define STD_SECTION(SEC, FLAGS, SYM, NAME, IDX) \
578 const asymbol * const SYM = (asymbol *) &global_syms[IDX]; \
579 const asection SEC = \
580 /* name, id, index, next, flags, user_set_vma, reloc_done, */ \
581 { NAME, IDX, 0, NULL, FLAGS, 0, 0, \
583 /* linker_mark, linker_has_input, gc_mark, segment_mark, */ \
586 /* vma, lma, _cooked_size, _raw_size, */ \
589 /* output_offset, output_section, alignment_power, */ \
590 0, (struct sec *) &SEC, 0, \
592 /* relocation, orelocation, reloc_count, filepos, rel_filepos, */ \
593 NULL, NULL, 0, 0, 0, \
595 /* line_filepos, userdata, contents, lineno, lineno_count, */ \
596 0, NULL, NULL, NULL, 0, \
598 /* entsize, comdat, moving_line_filepos, */ \
601 /* target_index, used_by_bfd, constructor_chain, owner, */ \
602 0, NULL, NULL, NULL, \
605 (struct symbol_cache_entry *) &global_syms[IDX], \
607 /* symbol_ptr_ptr, */ \
608 (struct symbol_cache_entry **) &SYM, \
610 /* link_order_head, link_order_tail */ \
614 STD_SECTION (bfd_com_section, SEC_IS_COMMON, bfd_com_symbol,
615 BFD_COM_SECTION_NAME, 0);
616 STD_SECTION (bfd_und_section, 0, bfd_und_symbol, BFD_UND_SECTION_NAME, 1);
617 STD_SECTION (bfd_abs_section, 0, bfd_abs_symbol, BFD_ABS_SECTION_NAME, 2);
618 STD_SECTION (bfd_ind_section, 0, bfd_ind_symbol, BFD_IND_SECTION_NAME, 3);
624 section prototypes, , typedef asection, Sections
628 These are the functions exported by the section handling part of BFD.
633 bfd_get_section_by_name
636 asection *bfd_get_section_by_name(bfd *abfd, const char *name);
639 Run through @var{abfd} and return the one of the
640 <<asection>>s whose name matches @var{name}, otherwise <<NULL>>.
641 @xref{Sections}, for more information.
643 This should only be used in special cases; the normal way to process
644 all sections of a given name is to use <<bfd_map_over_sections>> and
645 <<strcmp>> on the name (or better yet, base it on the section flags
646 or something else) for each section.
650 bfd_get_section_by_name (abfd, name)
656 for (sect = abfd->sections; sect != NULL; sect = sect->next)
657 if (!strcmp (sect->name, name))
664 bfd_get_unique_section_name
667 char *bfd_get_unique_section_name(bfd *abfd,
672 Invent a section name that is unique in @var{abfd} by tacking
673 a dot and a digit suffix onto the original @var{templat}. If
674 @var{count} is non-NULL, then it specifies the first number
675 tried as a suffix to generate a unique name. The value
676 pointed to by @var{count} will be incremented in this case.
680 bfd_get_unique_section_name (abfd, templat, count)
689 len = strlen (templat);
690 sname = bfd_malloc ((bfd_size_type) len + 8);
693 strcpy (sname, templat);
700 /* If we have a million sections, something is badly wrong. */
703 sprintf (sname + len, ".%d", num++);
705 while (bfd_get_section_by_name (abfd, sname) != NULL);
714 bfd_make_section_old_way
717 asection *bfd_make_section_old_way(bfd *abfd, const char *name);
720 Create a new empty section called @var{name}
721 and attach it to the end of the chain of sections for the
722 BFD @var{abfd}. An attempt to create a section with a name which
723 is already in use returns its pointer without changing the
726 It has the funny name since this is the way it used to be
727 before it was rewritten....
730 o <<bfd_error_invalid_operation>> -
731 If output has already started for this BFD.
732 o <<bfd_error_no_memory>> -
733 If memory allocation fails.
738 bfd_make_section_old_way (abfd, name)
742 asection *sec = bfd_get_section_by_name (abfd, name);
743 if (sec == (asection *) NULL)
745 sec = bfd_make_section (abfd, name);
752 bfd_make_section_anyway
755 asection *bfd_make_section_anyway(bfd *abfd, const char *name);
758 Create a new empty section called @var{name} and attach it to the end of
759 the chain of sections for @var{abfd}. Create a new section even if there
760 is already a section with that name.
762 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
763 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
764 o <<bfd_error_no_memory>> - If memory allocation fails.
768 bfd_make_section_anyway (abfd, name)
772 static int section_id = 0x10; /* id 0 to 3 used by STD_SECTION. */
774 asection **prev = &abfd->sections;
775 asection *sect = abfd->sections;
777 if (abfd->output_has_begun)
779 bfd_set_error (bfd_error_invalid_operation);
789 newsect = (asection *) bfd_zalloc (abfd, (bfd_size_type) sizeof (asection));
793 newsect->name = name;
794 newsect->id = section_id++;
795 newsect->index = abfd->section_count++;
796 newsect->flags = SEC_NO_FLAGS;
798 newsect->userdata = NULL;
799 newsect->contents = NULL;
800 newsect->next = (asection *) NULL;
801 newsect->relocation = (arelent *) NULL;
802 newsect->reloc_count = 0;
803 newsect->line_filepos = 0;
804 newsect->owner = abfd;
805 newsect->comdat = NULL;
807 /* Create a symbol whos only job is to point to this section. This is
808 useful for things like relocs which are relative to the base of a
810 newsect->symbol = bfd_make_empty_symbol (abfd);
811 if (newsect->symbol == NULL)
813 bfd_release (abfd, newsect);
816 newsect->symbol->name = name;
817 newsect->symbol->value = 0;
818 newsect->symbol->section = newsect;
819 newsect->symbol->flags = BSF_SECTION_SYM;
821 newsect->symbol_ptr_ptr = &newsect->symbol;
823 if (BFD_SEND (abfd, _new_section_hook, (abfd, newsect)) != true)
825 bfd_release (abfd, newsect);
838 asection *bfd_make_section(bfd *, const char *name);
841 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
842 bfd_set_error ()) without changing the section chain if there is already a
843 section named @var{name}. If there is an error, return <<NULL>> and set
848 bfd_make_section (abfd, name)
852 asection *sect = abfd->sections;
854 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0)
856 return bfd_abs_section_ptr;
858 if (strcmp (name, BFD_COM_SECTION_NAME) == 0)
860 return bfd_com_section_ptr;
862 if (strcmp (name, BFD_UND_SECTION_NAME) == 0)
864 return bfd_und_section_ptr;
867 if (strcmp (name, BFD_IND_SECTION_NAME) == 0)
869 return bfd_ind_section_ptr;
874 if (!strcmp (sect->name, name))
879 /* The name is not already used; go ahead and make a new section. */
880 return bfd_make_section_anyway (abfd, name);
885 bfd_set_section_flags
888 boolean bfd_set_section_flags(bfd *abfd, asection *sec, flagword flags);
891 Set the attributes of the section @var{sec} in the BFD
892 @var{abfd} to the value @var{flags}. Return <<true>> on success,
893 <<false>> on error. Possible error returns are:
895 o <<bfd_error_invalid_operation>> -
896 The section cannot have one or more of the attributes
897 requested. For example, a .bss section in <<a.out>> may not
898 have the <<SEC_HAS_CONTENTS>> field set.
904 bfd_set_section_flags (abfd, section, flags)
905 bfd *abfd ATTRIBUTE_UNUSED;
910 /* If you try to copy a text section from an input file (where it
911 has the SEC_CODE flag set) to an output file, this loses big if
912 the bfd_applicable_section_flags (abfd) doesn't have the SEC_CODE
913 set - which it doesn't, at least not for a.out. FIXME */
915 if ((flags & bfd_applicable_section_flags (abfd)) != flags)
917 bfd_set_error (bfd_error_invalid_operation);
922 section->flags = flags;
928 bfd_map_over_sections
931 void bfd_map_over_sections(bfd *abfd,
932 void (*func) (bfd *abfd,
938 Call the provided function @var{func} for each section
939 attached to the BFD @var{abfd}, passing @var{obj} as an
940 argument. The function will be called as if by
942 | func(abfd, the_section, obj);
944 This is the prefered method for iterating over sections; an
945 alternative would be to use a loop:
948 | for (p = abfd->sections; p != NULL; p = p->next)
955 bfd_map_over_sections (abfd, operation, user_storage)
957 void (*operation) PARAMS ((bfd * abfd, asection * sect, PTR obj));
963 for (sect = abfd->sections; sect != NULL; i++, sect = sect->next)
964 (*operation) (abfd, sect, user_storage);
966 if (i != abfd->section_count) /* Debugging */
975 boolean bfd_set_section_size(bfd *abfd, asection *sec, bfd_size_type val);
978 Set @var{sec} to the size @var{val}. If the operation is
979 ok, then <<true>> is returned, else <<false>>.
981 Possible error returns:
982 o <<bfd_error_invalid_operation>> -
983 Writing has started to the BFD, so setting the size is invalid.
988 bfd_set_section_size (abfd, ptr, val)
993 /* Once you've started writing to any section you cannot create or change
994 the size of any others. */
996 if (abfd->output_has_begun)
998 bfd_set_error (bfd_error_invalid_operation);
1002 ptr->_cooked_size = val;
1003 ptr->_raw_size = val;
1010 bfd_set_section_contents
1013 boolean bfd_set_section_contents (bfd *abfd, asection *section,
1014 PTR data, file_ptr offset,
1015 bfd_size_type count);
1018 Sets the contents of the section @var{section} in BFD
1019 @var{abfd} to the data starting in memory at @var{data}. The
1020 data is written to the output section starting at offset
1021 @var{offset} for @var{count} octets.
1023 Normally <<true>> is returned, else <<false>>. Possible error
1025 o <<bfd_error_no_contents>> -
1026 The output section does not have the <<SEC_HAS_CONTENTS>>
1027 attribute, so nothing can be written to it.
1030 This routine is front end to the back end function
1031 <<_bfd_set_section_contents>>.
1035 #define bfd_get_section_size_now(abfd,sec) \
1037 ? bfd_get_section_size_after_reloc (sec) \
1038 : bfd_get_section_size_before_reloc (sec))
1041 bfd_set_section_contents (abfd, section, location, offset, count)
1046 bfd_size_type count;
1050 if (!(bfd_get_section_flags (abfd, section) & SEC_HAS_CONTENTS))
1052 bfd_set_error (bfd_error_no_contents);
1056 sz = bfd_get_section_size_now (abfd, section);
1057 if ((bfd_size_type) offset > sz
1059 || offset + count > sz
1060 || count != (size_t) count)
1062 bfd_set_error (bfd_error_bad_value);
1066 switch (abfd->direction)
1068 case read_direction:
1070 bfd_set_error (bfd_error_invalid_operation);
1073 case write_direction:
1076 case both_direction:
1077 /* File is opened for update. `output_has_begun' some time ago when
1078 the file was created. Do not recompute sections sizes or alignments
1079 in _bfd_set_section_content. */
1080 abfd->output_has_begun = true;
1084 /* Record a copy of the data in memory if desired. */
1085 if (section->contents
1086 && location != section->contents + offset)
1087 memcpy (section->contents + offset, location, (size_t) count);
1089 if (BFD_SEND (abfd, _bfd_set_section_contents,
1090 (abfd, section, location, offset, count)))
1092 abfd->output_has_begun = true;
1101 bfd_get_section_contents
1104 boolean bfd_get_section_contents (bfd *abfd, asection *section,
1105 PTR location, file_ptr offset,
1106 bfd_size_type count);
1109 Read data from @var{section} in BFD @var{abfd}
1110 into memory starting at @var{location}. The data is read at an
1111 offset of @var{offset} from the start of the input section,
1112 and is read for @var{count} bytes.
1114 If the contents of a constructor with the <<SEC_CONSTRUCTOR>>
1115 flag set are requested or if the section does not have the
1116 <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled
1117 with zeroes. If no errors occur, <<true>> is returned, else
1122 bfd_get_section_contents (abfd, section, location, offset, count)
1127 bfd_size_type count;
1131 if (section->flags & SEC_CONSTRUCTOR)
1133 memset (location, 0, (size_t) count);
1137 /* Even if reloc_done is true, this function reads unrelocated
1138 contents, so we want the raw size. */
1139 sz = section->_raw_size;
1140 if ((bfd_size_type) offset > sz
1142 || offset + count > sz
1143 || count != (size_t) count)
1145 bfd_set_error (bfd_error_bad_value);
1153 if ((section->flags & SEC_HAS_CONTENTS) == 0)
1155 memset (location, 0, (size_t) count);
1159 if ((section->flags & SEC_IN_MEMORY) != 0)
1161 memcpy (location, section->contents + offset, (size_t) count);
1165 return BFD_SEND (abfd, _bfd_get_section_contents,
1166 (abfd, section, location, offset, count));
1171 bfd_copy_private_section_data
1174 boolean bfd_copy_private_section_data (bfd *ibfd, asection *isec,
1175 bfd *obfd, asection *osec);
1178 Copy private section information from @var{isec} in the BFD
1179 @var{ibfd} to the section @var{osec} in the BFD @var{obfd}.
1180 Return <<true>> on success, <<false>> on error. Possible error
1183 o <<bfd_error_no_memory>> -
1184 Not enough memory exists to create private data for @var{osec}.
1186 .#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \
1187 . BFD_SEND (obfd, _bfd_copy_private_section_data, \
1188 . (ibfd, isection, obfd, osection))
1193 _bfd_strip_section_from_output
1196 void _bfd_strip_section_from_output
1197 (struct bfd_link_info *info, asection *section);
1200 Remove @var{section} from the output. If the output section
1201 becomes empty, remove it from the output bfd. @var{info} may
1202 be NULL; if it is not, it is used to decide whether the output
1206 _bfd_strip_section_from_output (info, s)
1207 struct bfd_link_info *info;
1210 asection **spp, *os;
1211 struct bfd_link_order *p, *pp;
1214 /* Excise the input section from the link order.
1216 FIXME: For all calls that I can see to this function, the link
1217 orders have not yet been set up. So why are we checking them? --
1219 os = s->output_section;
1221 /* Handle a section that wasn't output. */
1225 for (p = os->link_order_head, pp = NULL; p != NULL; pp = p, p = p->next)
1226 if (p->type == bfd_indirect_link_order
1227 && p->u.indirect.section == s)
1232 os->link_order_head = p->next;
1234 os->link_order_tail = pp;
1238 keep_os = os->link_order_head != NULL;
1240 if (! keep_os && info != NULL)
1243 for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link_next)
1246 for (is = abfd->sections; is != NULL; is = is->next)
1248 if (is != s && is->output_section == os)
1258 /* If the output section is empty, remove it too. Careful about sections
1259 that have been discarded in the link script -- they are mapped to
1260 bfd_abs_section, which has no owner. */
1261 if (!keep_os && os->owner != NULL)
1263 for (spp = &os->owner->sections; *spp; spp = &(*spp)->next)
1267 os->owner->section_count--;