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 in the bfd; 0..n-1 as sections are created in a bfd. *}
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 based on the sum of
296 . the symbol and addend values specified by the associated relocation
297 . entries. Entries without associated relocation entries will be
298 . appended to the end of the section in an unspecified order. *}
299 .#define SEC_SORT_ENTRIES 0x80000
301 . {* When linking, duplicate sections of the same name should be
302 . discarded, rather than being combined into a single section as
303 . is usually done. This is similar to how common symbols are
304 . handled. See SEC_LINK_DUPLICATES below. *}
305 .#define SEC_LINK_ONCE 0x100000
307 . {* If SEC_LINK_ONCE is set, this bitfield describes how the linker
308 . should handle duplicate sections. *}
309 .#define SEC_LINK_DUPLICATES 0x600000
311 . {* This value for SEC_LINK_DUPLICATES means that duplicate
312 . sections with the same name should simply be discarded. *}
313 .#define SEC_LINK_DUPLICATES_DISCARD 0x0
315 . {* This value for SEC_LINK_DUPLICATES means that the linker
316 . should warn if there are any duplicate sections, although
317 . it should still only link one copy. *}
318 .#define SEC_LINK_DUPLICATES_ONE_ONLY 0x200000
320 . {* This value for SEC_LINK_DUPLICATES means that the linker
321 . should warn if any duplicate sections are a different size. *}
322 .#define SEC_LINK_DUPLICATES_SAME_SIZE 0x400000
324 . {* This value for SEC_LINK_DUPLICATES means that the linker
325 . should warn if any duplicate sections contain different
327 .#define SEC_LINK_DUPLICATES_SAME_CONTENTS 0x600000
329 . {* This section was created by the linker as part of dynamic
330 . relocation or other arcane processing. It is skipped when
331 . going through the first-pass output, trusting that someone
332 . else up the line will take care of it later. *}
333 .#define SEC_LINKER_CREATED 0x800000
335 . {* This section should not be subject to garbage collection. *}
336 .#define SEC_KEEP 0x1000000
338 . {* This section contains "short" data, and should be placed
340 .#define SEC_SMALL_DATA 0x2000000
342 . {* This section contains data which may be shared with other
343 . executables or shared objects. *}
344 .#define SEC_SHARED 0x4000000
346 . {* When a section with this flag is being linked, then if the size of
347 . the input section is less than a page, it should not cross a page
348 . boundary. If the size of the input section is one page or more, it
349 . should be aligned on a page boundary. *}
350 .#define SEC_BLOCK 0x8000000
352 . {* Conditionally link this section; do not link if there are no
353 . references found to any symbol in the section. *}
354 .#define SEC_CLINK 0x10000000
356 . {* Attempt to merge identical entities in the section.
357 . Entity size is given in the entsize field. *}
358 .#define SEC_MERGE 0x20000000
360 . {* If given with SEC_MERGE, entities to merge are zero terminated
361 . strings where entsize specifies character size instead of fixed
363 .#define SEC_STRINGS 0x40000000
365 . {* This section contains data about section groups. *}
366 .#define SEC_GROUP 0x80000000
368 . {* End of section flags. *}
370 . {* Some internal packed boolean fields. *}
372 . {* See the vma field. *}
373 . unsigned int user_set_vma : 1;
375 . {* Whether relocations have been processed. *}
376 . unsigned int reloc_done : 1;
378 . {* A mark flag used by some of the linker backends. *}
379 . unsigned int linker_mark : 1;
381 . {* Another mark flag used by some of the linker backends. Set for
382 . output sections that have an input section. *}
383 . unsigned int linker_has_input : 1;
385 . {* A mark flag used by some linker backends for garbage collection. *}
386 . unsigned int gc_mark : 1;
388 . {* Used by the ELF code to mark sections which have been allocated
390 . unsigned int segment_mark : 1;
392 . {* End of internal packed boolean fields. *}
394 . {* The virtual memory address of the section - where it will be
395 . at run time. The symbols are relocated against this. The
396 . user_set_vma flag is maintained by bfd; if it's not set, the
397 . backend can assign addresses (for example, in <<a.out>>, where
398 . the default address for <<.data>> is dependent on the specific
399 . target and various flags). *}
403 . {* The load address of the section - where it would be in a
404 . rom image; really only used for writing section header
409 . {* The size of the section in octets, as it will be output.
410 . Contains a value even if the section has no contents (e.g., the
411 . size of <<.bss>>). This will be filled in after relocation. *}
413 . bfd_size_type _cooked_size;
415 . {* The original size on disk of the section, in octets. Normally this
416 . value is the same as the size, but if some relaxing has
417 . been done, then this value will be bigger. *}
419 . bfd_size_type _raw_size;
421 . {* If this section is going to be output, then this value is the
422 . offset in *bytes* into the output section of the first byte in the
423 . input section (byte ==> smallest addressable unit on the
424 . target). In most cases, if this was going to start at the
425 . 100th octet (8-bit quantity) in the output section, this value
426 . would be 100. However, if the target byte size is 16 bits
427 . (bfd_octets_per_byte is "2"), this value would be 50. *}
429 . bfd_vma output_offset;
431 . {* The output section through which to map on output. *}
433 . struct sec *output_section;
435 . {* The alignment requirement of the section, as an exponent of 2 -
436 . e.g., 3 aligns to 2^3 (or 8). *}
438 . unsigned int alignment_power;
440 . {* If an input section, a pointer to a vector of relocation
441 . records for the data in this section. *}
443 . struct reloc_cache_entry *relocation;
445 . {* If an output section, a pointer to a vector of pointers to
446 . relocation records for the data in this section. *}
448 . struct reloc_cache_entry **orelocation;
450 . {* The number of relocation records in one of the above *}
452 . unsigned reloc_count;
454 . {* Information below is back end specific - and not always used
457 . {* File position of section data. *}
461 . {* File position of relocation info. *}
463 . file_ptr rel_filepos;
465 . {* File position of line data. *}
467 . file_ptr line_filepos;
469 . {* Pointer to data for applications. *}
473 . {* If the SEC_IN_MEMORY flag is set, this points to the actual
475 . unsigned char *contents;
477 . {* Attached line number information. *}
481 . {* Number of line number records. *}
483 . unsigned int lineno_count;
485 . {* Entity size for merging purposes. *}
487 . unsigned int entsize;
489 . {* Optional information about a COMDAT entry; NULL if not COMDAT. *}
491 . struct bfd_comdat_info *comdat;
493 . {* When a section is being output, this value changes as more
494 . linenumbers are written out. *}
496 . file_ptr moving_line_filepos;
498 . {* What the section number is in the target world. *}
504 . {* If this is a constructor section then here is a list of the
505 . relocations created to relocate items within it. *}
507 . struct relent_chain *constructor_chain;
509 . {* The BFD which owns the section. *}
513 . {* A symbol which points at this section only *}
514 . struct symbol_cache_entry *symbol;
515 . struct symbol_cache_entry **symbol_ptr_ptr;
517 . struct bfd_link_order *link_order_head;
518 . struct bfd_link_order *link_order_tail;
521 .{* These sections are global, and are managed by BFD. The application
522 . and target back end are not permitted to change the values in
523 . these sections. New code should use the section_ptr macros rather
524 . than referring directly to the const sections. The const sections
525 . may eventually vanish. *}
526 .#define BFD_ABS_SECTION_NAME "*ABS*"
527 .#define BFD_UND_SECTION_NAME "*UND*"
528 .#define BFD_COM_SECTION_NAME "*COM*"
529 .#define BFD_IND_SECTION_NAME "*IND*"
531 .{* the absolute section *}
532 .extern const asection bfd_abs_section;
533 .#define bfd_abs_section_ptr ((asection *) &bfd_abs_section)
534 .#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr)
535 .{* Pointer to the undefined section *}
536 .extern const asection bfd_und_section;
537 .#define bfd_und_section_ptr ((asection *) &bfd_und_section)
538 .#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr)
539 .{* Pointer to the common section *}
540 .extern const asection bfd_com_section;
541 .#define bfd_com_section_ptr ((asection *) &bfd_com_section)
542 .{* Pointer to the indirect section *}
543 .extern const asection bfd_ind_section;
544 .#define bfd_ind_section_ptr ((asection *) &bfd_ind_section)
545 .#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr)
547 .#define bfd_is_const_section(SEC) \
548 . ( ((SEC) == bfd_abs_section_ptr) \
549 . || ((SEC) == bfd_und_section_ptr) \
550 . || ((SEC) == bfd_com_section_ptr) \
551 . || ((SEC) == bfd_ind_section_ptr))
553 .extern const struct symbol_cache_entry * const bfd_abs_symbol;
554 .extern const struct symbol_cache_entry * const bfd_com_symbol;
555 .extern const struct symbol_cache_entry * const bfd_und_symbol;
556 .extern const struct symbol_cache_entry * const bfd_ind_symbol;
557 .#define bfd_get_section_size_before_reloc(section) \
558 . ((section)->reloc_done ? (abort (), (bfd_size_type) 1) \
559 . : (section)->_raw_size)
560 .#define bfd_get_section_size_after_reloc(section) \
561 . ((section)->reloc_done ? (section)->_cooked_size \
562 . : (abort (), (bfd_size_type) 1))
565 /* We use a macro to initialize the static asymbol structures because
566 traditional C does not permit us to initialize a union member while
567 gcc warns if we don't initialize it. */
568 /* the_bfd, name, value, attr, section [, udata] */
570 #define GLOBAL_SYM_INIT(NAME, SECTION) \
571 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION, { 0 }}
573 #define GLOBAL_SYM_INIT(NAME, SECTION) \
574 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION }
577 /* These symbols are global, not specific to any BFD. Therefore, anything
578 that tries to change them is broken, and should be repaired. */
580 static const asymbol global_syms[] =
582 GLOBAL_SYM_INIT (BFD_COM_SECTION_NAME, &bfd_com_section),
583 GLOBAL_SYM_INIT (BFD_UND_SECTION_NAME, &bfd_und_section),
584 GLOBAL_SYM_INIT (BFD_ABS_SECTION_NAME, &bfd_abs_section),
585 GLOBAL_SYM_INIT (BFD_IND_SECTION_NAME, &bfd_ind_section)
588 #define STD_SECTION(SEC, FLAGS, SYM, NAME, IDX) \
589 const asymbol * const SYM = (asymbol *) &global_syms[IDX]; \
590 const asection SEC = \
591 /* name, id, index, next, flags, user_set_vma, reloc_done, */ \
592 { NAME, IDX, 0, NULL, FLAGS, 0, 0, \
594 /* linker_mark, linker_has_input, gc_mark, segment_mark, */ \
597 /* vma, lma, _cooked_size, _raw_size, */ \
600 /* output_offset, output_section, alignment_power, */ \
601 0, (struct sec *) &SEC, 0, \
603 /* relocation, orelocation, reloc_count, filepos, rel_filepos, */ \
604 NULL, NULL, 0, 0, 0, \
606 /* line_filepos, userdata, contents, lineno, lineno_count, */ \
607 0, NULL, NULL, NULL, 0, \
609 /* entsize, comdat, moving_line_filepos, */ \
612 /* target_index, used_by_bfd, constructor_chain, owner, */ \
613 0, NULL, NULL, NULL, \
616 (struct symbol_cache_entry *) &global_syms[IDX], \
618 /* symbol_ptr_ptr, */ \
619 (struct symbol_cache_entry **) &SYM, \
621 /* link_order_head, link_order_tail */ \
625 STD_SECTION (bfd_com_section, SEC_IS_COMMON, bfd_com_symbol,
626 BFD_COM_SECTION_NAME, 0);
627 STD_SECTION (bfd_und_section, 0, bfd_und_symbol, BFD_UND_SECTION_NAME, 1);
628 STD_SECTION (bfd_abs_section, 0, bfd_abs_symbol, BFD_ABS_SECTION_NAME, 2);
629 STD_SECTION (bfd_ind_section, 0, bfd_ind_symbol, BFD_IND_SECTION_NAME, 3);
635 section prototypes, , typedef asection, Sections
639 These are the functions exported by the section handling part of BFD.
644 bfd_get_section_by_name
647 asection *bfd_get_section_by_name(bfd *abfd, const char *name);
650 Run through @var{abfd} and return the one of the
651 <<asection>>s whose name matches @var{name}, otherwise <<NULL>>.
652 @xref{Sections}, for more information.
654 This should only be used in special cases; the normal way to process
655 all sections of a given name is to use <<bfd_map_over_sections>> and
656 <<strcmp>> on the name (or better yet, base it on the section flags
657 or something else) for each section.
661 bfd_get_section_by_name (abfd, name)
667 for (sect = abfd->sections; sect != NULL; sect = sect->next)
668 if (!strcmp (sect->name, name))
675 bfd_get_unique_section_name
678 char *bfd_get_unique_section_name(bfd *abfd,
683 Invent a section name that is unique in @var{abfd} by tacking
684 a dot and a digit suffix onto the original @var{templat}. If
685 @var{count} is non-NULL, then it specifies the first number
686 tried as a suffix to generate a unique name. The value
687 pointed to by @var{count} will be incremented in this case.
691 bfd_get_unique_section_name (abfd, templat, count)
700 len = strlen (templat);
701 sname = bfd_malloc ((bfd_size_type) len + 8);
704 strcpy (sname, templat);
711 /* If we have a million sections, something is badly wrong. */
714 sprintf (sname + len, ".%d", num++);
716 while (bfd_get_section_by_name (abfd, sname) != NULL);
725 bfd_make_section_old_way
728 asection *bfd_make_section_old_way(bfd *abfd, const char *name);
731 Create a new empty section called @var{name}
732 and attach it to the end of the chain of sections for the
733 BFD @var{abfd}. An attempt to create a section with a name which
734 is already in use returns its pointer without changing the
737 It has the funny name since this is the way it used to be
738 before it was rewritten....
741 o <<bfd_error_invalid_operation>> -
742 If output has already started for this BFD.
743 o <<bfd_error_no_memory>> -
744 If memory allocation fails.
749 bfd_make_section_old_way (abfd, name)
753 asection *sec = bfd_get_section_by_name (abfd, name);
754 if (sec == (asection *) NULL)
756 sec = bfd_make_section (abfd, name);
763 bfd_make_section_anyway
766 asection *bfd_make_section_anyway(bfd *abfd, const char *name);
769 Create a new empty section called @var{name} and attach it to the end of
770 the chain of sections for @var{abfd}. Create a new section even if there
771 is already a section with that name.
773 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
774 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
775 o <<bfd_error_no_memory>> - If memory allocation fails.
779 bfd_make_section_anyway (abfd, name)
783 static int section_id = 0x10; /* id 0 to 3 used by STD_SECTION. */
785 asection **prev = &abfd->sections;
786 asection *sect = abfd->sections;
788 if (abfd->output_has_begun)
790 bfd_set_error (bfd_error_invalid_operation);
800 newsect = (asection *) bfd_zalloc (abfd, (bfd_size_type) sizeof (asection));
804 newsect->name = name;
805 newsect->id = section_id;
806 newsect->index = abfd->section_count;
807 newsect->flags = SEC_NO_FLAGS;
809 newsect->userdata = NULL;
810 newsect->contents = NULL;
811 newsect->next = (asection *) NULL;
812 newsect->relocation = (arelent *) NULL;
813 newsect->reloc_count = 0;
814 newsect->line_filepos = 0;
815 newsect->owner = abfd;
816 newsect->comdat = NULL;
818 /* Create a symbol whos only job is to point to this section. This is
819 useful for things like relocs which are relative to the base of a
821 newsect->symbol = bfd_make_empty_symbol (abfd);
822 if (newsect->symbol == NULL)
824 bfd_release (abfd, newsect);
827 newsect->symbol->name = name;
828 newsect->symbol->value = 0;
829 newsect->symbol->section = newsect;
830 newsect->symbol->flags = BSF_SECTION_SYM;
832 newsect->symbol_ptr_ptr = &newsect->symbol;
834 if (BFD_SEND (abfd, _new_section_hook, (abfd, newsect)) != true)
836 bfd_release (abfd, newsect);
841 abfd->section_count++;
851 asection *bfd_make_section(bfd *, const char *name);
854 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
855 bfd_set_error ()) without changing the section chain if there is already a
856 section named @var{name}. If there is an error, return <<NULL>> and set
861 bfd_make_section (abfd, name)
865 asection *sect = abfd->sections;
867 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0)
869 return bfd_abs_section_ptr;
871 if (strcmp (name, BFD_COM_SECTION_NAME) == 0)
873 return bfd_com_section_ptr;
875 if (strcmp (name, BFD_UND_SECTION_NAME) == 0)
877 return bfd_und_section_ptr;
880 if (strcmp (name, BFD_IND_SECTION_NAME) == 0)
882 return bfd_ind_section_ptr;
887 if (!strcmp (sect->name, name))
892 /* The name is not already used; go ahead and make a new section. */
893 return bfd_make_section_anyway (abfd, name);
898 bfd_set_section_flags
901 boolean bfd_set_section_flags(bfd *abfd, asection *sec, flagword flags);
904 Set the attributes of the section @var{sec} in the BFD
905 @var{abfd} to the value @var{flags}. Return <<true>> on success,
906 <<false>> on error. Possible error returns are:
908 o <<bfd_error_invalid_operation>> -
909 The section cannot have one or more of the attributes
910 requested. For example, a .bss section in <<a.out>> may not
911 have the <<SEC_HAS_CONTENTS>> field set.
917 bfd_set_section_flags (abfd, section, flags)
918 bfd *abfd ATTRIBUTE_UNUSED;
923 /* If you try to copy a text section from an input file (where it
924 has the SEC_CODE flag set) to an output file, this loses big if
925 the bfd_applicable_section_flags (abfd) doesn't have the SEC_CODE
926 set - which it doesn't, at least not for a.out. FIXME */
928 if ((flags & bfd_applicable_section_flags (abfd)) != flags)
930 bfd_set_error (bfd_error_invalid_operation);
935 section->flags = flags;
941 bfd_map_over_sections
944 void bfd_map_over_sections(bfd *abfd,
945 void (*func) (bfd *abfd,
951 Call the provided function @var{func} for each section
952 attached to the BFD @var{abfd}, passing @var{obj} as an
953 argument. The function will be called as if by
955 | func(abfd, the_section, obj);
957 This is the prefered method for iterating over sections; an
958 alternative would be to use a loop:
961 | for (p = abfd->sections; p != NULL; p = p->next)
968 bfd_map_over_sections (abfd, operation, user_storage)
970 void (*operation) PARAMS ((bfd * abfd, asection * sect, PTR obj));
976 for (sect = abfd->sections; sect != NULL; i++, sect = sect->next)
977 (*operation) (abfd, sect, user_storage);
979 if (i != abfd->section_count) /* Debugging */
988 boolean bfd_set_section_size(bfd *abfd, asection *sec, bfd_size_type val);
991 Set @var{sec} to the size @var{val}. If the operation is
992 ok, then <<true>> is returned, else <<false>>.
994 Possible error returns:
995 o <<bfd_error_invalid_operation>> -
996 Writing has started to the BFD, so setting the size is invalid.
1001 bfd_set_section_size (abfd, ptr, val)
1006 /* Once you've started writing to any section you cannot create or change
1007 the size of any others. */
1009 if (abfd->output_has_begun)
1011 bfd_set_error (bfd_error_invalid_operation);
1015 ptr->_cooked_size = val;
1016 ptr->_raw_size = val;
1023 bfd_set_section_contents
1026 boolean bfd_set_section_contents (bfd *abfd, asection *section,
1027 PTR data, file_ptr offset,
1028 bfd_size_type count);
1031 Sets the contents of the section @var{section} in BFD
1032 @var{abfd} to the data starting in memory at @var{data}. The
1033 data is written to the output section starting at offset
1034 @var{offset} for @var{count} octets.
1036 Normally <<true>> is returned, else <<false>>. Possible error
1038 o <<bfd_error_no_contents>> -
1039 The output section does not have the <<SEC_HAS_CONTENTS>>
1040 attribute, so nothing can be written to it.
1043 This routine is front end to the back end function
1044 <<_bfd_set_section_contents>>.
1048 #define bfd_get_section_size_now(abfd,sec) \
1050 ? bfd_get_section_size_after_reloc (sec) \
1051 : bfd_get_section_size_before_reloc (sec))
1054 bfd_set_section_contents (abfd, section, location, offset, count)
1059 bfd_size_type count;
1063 if (!(bfd_get_section_flags (abfd, section) & SEC_HAS_CONTENTS))
1065 bfd_set_error (bfd_error_no_contents);
1069 sz = bfd_get_section_size_now (abfd, section);
1070 if ((bfd_size_type) offset > sz
1072 || offset + count > sz
1073 || count != (size_t) count)
1075 bfd_set_error (bfd_error_bad_value);
1079 switch (abfd->direction)
1081 case read_direction:
1083 bfd_set_error (bfd_error_invalid_operation);
1086 case write_direction:
1089 case both_direction:
1090 /* File is opened for update. `output_has_begun' some time ago when
1091 the file was created. Do not recompute sections sizes or alignments
1092 in _bfd_set_section_content. */
1093 abfd->output_has_begun = true;
1097 /* Record a copy of the data in memory if desired. */
1098 if (section->contents
1099 && location != section->contents + offset)
1100 memcpy (section->contents + offset, location, (size_t) count);
1102 if (BFD_SEND (abfd, _bfd_set_section_contents,
1103 (abfd, section, location, offset, count)))
1105 abfd->output_has_begun = true;
1114 bfd_get_section_contents
1117 boolean bfd_get_section_contents (bfd *abfd, asection *section,
1118 PTR location, file_ptr offset,
1119 bfd_size_type count);
1122 Read data from @var{section} in BFD @var{abfd}
1123 into memory starting at @var{location}. The data is read at an
1124 offset of @var{offset} from the start of the input section,
1125 and is read for @var{count} bytes.
1127 If the contents of a constructor with the <<SEC_CONSTRUCTOR>>
1128 flag set are requested or if the section does not have the
1129 <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled
1130 with zeroes. If no errors occur, <<true>> is returned, else
1135 bfd_get_section_contents (abfd, section, location, offset, count)
1140 bfd_size_type count;
1144 if (section->flags & SEC_CONSTRUCTOR)
1146 memset (location, 0, (size_t) count);
1150 /* Even if reloc_done is true, this function reads unrelocated
1151 contents, so we want the raw size. */
1152 sz = section->_raw_size;
1153 if ((bfd_size_type) offset > sz
1155 || offset + count > sz
1156 || count != (size_t) count)
1158 bfd_set_error (bfd_error_bad_value);
1166 if ((section->flags & SEC_HAS_CONTENTS) == 0)
1168 memset (location, 0, (size_t) count);
1172 if ((section->flags & SEC_IN_MEMORY) != 0)
1174 memcpy (location, section->contents + offset, (size_t) count);
1178 return BFD_SEND (abfd, _bfd_get_section_contents,
1179 (abfd, section, location, offset, count));
1184 bfd_copy_private_section_data
1187 boolean bfd_copy_private_section_data (bfd *ibfd, asection *isec,
1188 bfd *obfd, asection *osec);
1191 Copy private section information from @var{isec} in the BFD
1192 @var{ibfd} to the section @var{osec} in the BFD @var{obfd}.
1193 Return <<true>> on success, <<false>> on error. Possible error
1196 o <<bfd_error_no_memory>> -
1197 Not enough memory exists to create private data for @var{osec}.
1199 .#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \
1200 . BFD_SEND (obfd, _bfd_copy_private_section_data, \
1201 . (ibfd, isection, obfd, osection))
1206 _bfd_strip_section_from_output
1209 void _bfd_strip_section_from_output
1210 (struct bfd_link_info *info, asection *section);
1213 Remove @var{section} from the output. If the output section
1214 becomes empty, remove it from the output bfd. @var{info} may
1215 be NULL; if it is not, it is used to decide whether the output
1219 _bfd_strip_section_from_output (info, s)
1220 struct bfd_link_info *info;
1223 asection **spp, *os;
1224 struct bfd_link_order *p, *pp;
1227 /* Excise the input section from the link order.
1229 FIXME: For all calls that I can see to this function, the link
1230 orders have not yet been set up. So why are we checking them? --
1232 os = s->output_section;
1234 /* Handle a section that wasn't output. */
1238 for (p = os->link_order_head, pp = NULL; p != NULL; pp = p, p = p->next)
1239 if (p->type == bfd_indirect_link_order
1240 && p->u.indirect.section == s)
1245 os->link_order_head = p->next;
1247 os->link_order_tail = pp;
1251 keep_os = os->link_order_head != NULL;
1253 if (! keep_os && info != NULL)
1256 for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link_next)
1259 for (is = abfd->sections; is != NULL; is = is->next)
1261 if (is != s && is->output_section == os
1262 && (is->flags & SEC_EXCLUDE) == 0)
1272 /* If the output section is empty, remove it too. Careful about sections
1273 that have been discarded in the link script -- they are mapped to
1274 bfd_abs_section, which has no owner. */
1275 if (!keep_os && os->owner != NULL)
1277 for (spp = &os->owner->sections; *spp; spp = &(*spp)->next)
1281 os->owner->section_count--;
1286 s->flags |= SEC_EXCLUDE;