1 /* Object file "section" support for the BFD library.
2 Copyright (C) 1990-2017 Free Software Foundation, Inc.
3 Written by Cygnus Support.
5 This file is part of BFD, the Binary File Descriptor library.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
20 MA 02110-1301, USA. */
26 The raw data contained within a BFD is maintained through the
27 section abstraction. A single BFD may have any number of
28 sections. It keeps hold of them by pointing to the first;
29 each one points to the next in the list.
31 Sections are supported in BFD in <<section.c>>.
37 @* section prototypes::
41 Section Input, Section Output, Sections, Sections
45 When a BFD is opened for reading, the section structures are
46 created and attached to the BFD.
48 Each section has a name which describes the section in the
49 outside world---for example, <<a.out>> would contain at least
50 three sections, called <<.text>>, <<.data>> and <<.bss>>.
52 Names need not be unique; for example a COFF file may have several
53 sections named <<.data>>.
55 Sometimes a BFD will contain more than the ``natural'' number of
56 sections. A back end may attach other sections containing
57 constructor data, or an application may add a section (using
58 <<bfd_make_section>>) to the sections attached to an already open
59 BFD. For example, the linker creates an extra section
60 <<COMMON>> for each input file's BFD to hold information about
63 The raw data is not necessarily read in when
64 the section descriptor is created. Some targets may leave the
65 data in place until a <<bfd_get_section_contents>> call is
66 made. Other back ends may read in all the data at once. For
67 example, an S-record file has to be read once to determine the
68 size of the data. An IEEE-695 file doesn't contain raw data in
69 sections, but data and relocation expressions intermixed, so
70 the data area has to be parsed to get out the data and
74 Section Output, typedef asection, Section Input, Sections
79 To write a new object style BFD, the various sections to be
80 written have to be created. They are attached to the BFD in
81 the same way as input sections; data is written to the
82 sections using <<bfd_set_section_contents>>.
84 Any program that creates or combines sections (e.g., the assembler
85 and linker) must use the <<asection>> fields <<output_section>> and
86 <<output_offset>> to indicate the file sections to which each
87 section must be written. (If the section is being created from
88 scratch, <<output_section>> should probably point to the section
89 itself and <<output_offset>> should probably be zero.)
91 The data to be written comes from input sections attached
92 (via <<output_section>> pointers) to
93 the output sections. The output section structure can be
94 considered a filter for the input section: the output section
95 determines the vma of the output data and the name, but the
96 input section determines the offset into the output section of
97 the data to be written.
99 E.g., to create a section "O", starting at 0x100, 0x123 long,
100 containing two subsections, "A" at offset 0x0 (i.e., at vma
101 0x100) and "B" at offset 0x20 (i.e., at vma 0x120) the <<asection>>
102 structures would look like:
107 | output_section -----------> section name "O"
109 | section name "B" | size 0x123
110 | output_offset 0x20 |
112 | output_section --------|
117 The data within a section is stored in a @dfn{link_order}.
118 These are much like the fixups in <<gas>>. The link_order
119 abstraction allows a section to grow and shrink within itself.
121 A link_order knows how big it is, and which is the next
122 link_order and where the raw data for it is; it also points to
123 a list of relocations which apply to it.
125 The link_order is used by the linker to perform relaxing on
126 final code. The compiler creates code which is as big as
127 necessary to make it work without relaxing, and the user can
128 select whether to relax. Sometimes relaxing takes a lot of
129 time. The linker runs around the relocations to see if any
130 are attached to data which can be shrunk, if so it does it on
131 a link_order by link_order basis.
143 typedef asection, section prototypes, Section Output, Sections
147 Here is the section structure:
151 .typedef struct bfd_section
153 . {* The name of the section; the name isn't a copy, the pointer is
154 . the same as that passed to bfd_make_section. *}
157 . {* A unique sequence number. *}
160 . {* Which section in the bfd; 0..n-1 as sections are created in a bfd. *}
161 . unsigned int index;
163 . {* The next section in the list belonging to the BFD, or NULL. *}
164 . struct bfd_section *next;
166 . {* The previous section in the list belonging to the BFD, or NULL. *}
167 . struct bfd_section *prev;
169 . {* The field flags contains attributes of the section. Some
170 . flags are read in from the object file, and some are
171 . synthesized from other information. *}
174 .#define SEC_NO_FLAGS 0x0
176 . {* Tells the OS to allocate space for this section when loading.
177 . This is clear for a section containing debug information only. *}
178 .#define SEC_ALLOC 0x1
180 . {* Tells the OS to load the section from the file when loading.
181 . This is clear for a .bss section. *}
182 .#define SEC_LOAD 0x2
184 . {* The section contains data still to be relocated, so there is
185 . some relocation information too. *}
186 .#define SEC_RELOC 0x4
188 . {* A signal to the OS that the section contains read only data. *}
189 .#define SEC_READONLY 0x8
191 . {* The section contains code only. *}
192 .#define SEC_CODE 0x10
194 . {* The section contains data only. *}
195 .#define SEC_DATA 0x20
197 . {* The section will reside in ROM. *}
198 .#define SEC_ROM 0x40
200 . {* The section contains constructor information. This section
201 . type is used by the linker to create lists of constructors and
202 . destructors used by <<g++>>. When a back end sees a symbol
203 . which should be used in a constructor list, it creates a new
204 . section for the type of name (e.g., <<__CTOR_LIST__>>), attaches
205 . the symbol to it, and builds a relocation. To build the lists
206 . of constructors, all the linker has to do is catenate all the
207 . sections called <<__CTOR_LIST__>> and relocate the data
208 . contained within - exactly the operations it would peform on
210 .#define SEC_CONSTRUCTOR 0x80
212 . {* The section has contents - a data section could be
213 . <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>; a debug section could be
214 . <<SEC_HAS_CONTENTS>> *}
215 .#define SEC_HAS_CONTENTS 0x100
217 . {* An instruction to the linker to not output the section
218 . even if it has information which would normally be written. *}
219 .#define SEC_NEVER_LOAD 0x200
221 . {* The section contains thread local data. *}
222 .#define SEC_THREAD_LOCAL 0x400
224 . {* The section has GOT references. This flag is only for the
225 . linker, and is currently only used by the elf32-hppa back end.
226 . It will be set if global offset table references were detected
227 . in this section, which indicate to the linker that the section
228 . contains PIC code, and must be handled specially when doing a
230 .#define SEC_HAS_GOT_REF 0x800
232 . {* The section contains common symbols (symbols may be defined
233 . multiple times, the value of a symbol is the amount of
234 . space it requires, and the largest symbol value is the one
235 . used). Most targets have exactly one of these (which we
236 . translate to bfd_com_section_ptr), but ECOFF has two. *}
237 .#define SEC_IS_COMMON 0x1000
239 . {* The section contains only debugging information. For
240 . example, this is set for ELF .debug and .stab sections.
241 . strip tests this flag to see if a section can be
243 .#define SEC_DEBUGGING 0x2000
245 . {* The contents of this section are held in memory pointed to
246 . by the contents field. This is checked by bfd_get_section_contents,
247 . and the data is retrieved from memory if appropriate. *}
248 .#define SEC_IN_MEMORY 0x4000
250 . {* The contents of this section are to be excluded by the
251 . linker for executable and shared objects unless those
252 . objects are to be further relocated. *}
253 .#define SEC_EXCLUDE 0x8000
255 . {* The contents of this section are to be sorted based on the sum of
256 . the symbol and addend values specified by the associated relocation
257 . entries. Entries without associated relocation entries will be
258 . appended to the end of the section in an unspecified order. *}
259 .#define SEC_SORT_ENTRIES 0x10000
261 . {* When linking, duplicate sections of the same name should be
262 . discarded, rather than being combined into a single section as
263 . is usually done. This is similar to how common symbols are
264 . handled. See SEC_LINK_DUPLICATES below. *}
265 .#define SEC_LINK_ONCE 0x20000
267 . {* If SEC_LINK_ONCE is set, this bitfield describes how the linker
268 . should handle duplicate sections. *}
269 .#define SEC_LINK_DUPLICATES 0xc0000
271 . {* This value for SEC_LINK_DUPLICATES means that duplicate
272 . sections with the same name should simply be discarded. *}
273 .#define SEC_LINK_DUPLICATES_DISCARD 0x0
275 . {* This value for SEC_LINK_DUPLICATES means that the linker
276 . should warn if there are any duplicate sections, although
277 . it should still only link one copy. *}
278 .#define SEC_LINK_DUPLICATES_ONE_ONLY 0x40000
280 . {* This value for SEC_LINK_DUPLICATES means that the linker
281 . should warn if any duplicate sections are a different size. *}
282 .#define SEC_LINK_DUPLICATES_SAME_SIZE 0x80000
284 . {* This value for SEC_LINK_DUPLICATES means that the linker
285 . should warn if any duplicate sections contain different
287 .#define SEC_LINK_DUPLICATES_SAME_CONTENTS \
288 . (SEC_LINK_DUPLICATES_ONE_ONLY | SEC_LINK_DUPLICATES_SAME_SIZE)
290 . {* This section was created by the linker as part of dynamic
291 . relocation or other arcane processing. It is skipped when
292 . going through the first-pass output, trusting that someone
293 . else up the line will take care of it later. *}
294 .#define SEC_LINKER_CREATED 0x100000
296 . {* This section should not be subject to garbage collection.
297 . Also set to inform the linker that this section should not be
298 . listed in the link map as discarded. *}
299 .#define SEC_KEEP 0x200000
301 . {* This section contains "short" data, and should be placed
303 .#define SEC_SMALL_DATA 0x400000
305 . {* Attempt to merge identical entities in the section.
306 . Entity size is given in the entsize field. *}
307 .#define SEC_MERGE 0x800000
309 . {* If given with SEC_MERGE, entities to merge are zero terminated
310 . strings where entsize specifies character size instead of fixed
312 .#define SEC_STRINGS 0x1000000
314 . {* This section contains data about section groups. *}
315 .#define SEC_GROUP 0x2000000
317 . {* The section is a COFF shared library section. This flag is
318 . only for the linker. If this type of section appears in
319 . the input file, the linker must copy it to the output file
320 . without changing the vma or size. FIXME: Although this
321 . was originally intended to be general, it really is COFF
322 . specific (and the flag was renamed to indicate this). It
323 . might be cleaner to have some more general mechanism to
324 . allow the back end to control what the linker does with
326 .#define SEC_COFF_SHARED_LIBRARY 0x4000000
328 . {* This input section should be copied to output in reverse order
329 . as an array of pointers. This is for ELF linker internal use
331 .#define SEC_ELF_REVERSE_COPY 0x4000000
333 . {* This section contains data which may be shared with other
334 . executables or shared objects. This is for COFF only. *}
335 .#define SEC_COFF_SHARED 0x8000000
337 . {* This section should be compressed. This is for ELF linker
338 . internal use only. *}
339 .#define SEC_ELF_COMPRESS 0x8000000
341 . {* When a section with this flag is being linked, then if the size of
342 . the input section is less than a page, it should not cross a page
343 . boundary. If the size of the input section is one page or more,
344 . it should be aligned on a page boundary. This is for TI
345 . TMS320C54X only. *}
346 .#define SEC_TIC54X_BLOCK 0x10000000
348 . {* This section should be renamed. This is for ELF linker
349 . internal use only. *}
350 .#define SEC_ELF_RENAME 0x10000000
352 . {* Conditionally link this section; do not link if there are no
353 . references found to any symbol in the section. This is for TI
354 . TMS320C54X only. *}
355 .#define SEC_TIC54X_CLINK 0x20000000
357 . {* This section contains vliw code. This is for Toshiba MeP only. *}
358 .#define SEC_MEP_VLIW 0x20000000
360 . {* Indicate that section has the no read flag set. This happens
361 . when memory read flag isn't set. *}
362 .#define SEC_COFF_NOREAD 0x40000000
364 . {* Indicate that section has the purecode flag set. *}
365 .#define SEC_ELF_PURECODE 0x80000000
367 . {* End of section flags. *}
369 . {* Some internal packed boolean fields. *}
371 . {* See the vma field. *}
372 . unsigned int user_set_vma : 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 an input section. *}
379 . unsigned int linker_has_input : 1;
381 . {* Mark flag used by some linker backends for garbage collection. *}
382 . unsigned int gc_mark : 1;
384 . {* Section compression status. *}
385 . unsigned int compress_status : 2;
386 .#define COMPRESS_SECTION_NONE 0
387 .#define COMPRESS_SECTION_DONE 1
388 .#define DECOMPRESS_SECTION_SIZED 2
390 . {* The following flags are used by the ELF linker. *}
392 . {* Mark sections which have been allocated to segments. *}
393 . unsigned int segment_mark : 1;
395 . {* Type of sec_info information. *}
396 . unsigned int sec_info_type:3;
397 .#define SEC_INFO_TYPE_NONE 0
398 .#define SEC_INFO_TYPE_STABS 1
399 .#define SEC_INFO_TYPE_MERGE 2
400 .#define SEC_INFO_TYPE_EH_FRAME 3
401 .#define SEC_INFO_TYPE_JUST_SYMS 4
402 .#define SEC_INFO_TYPE_TARGET 5
403 .#define SEC_INFO_TYPE_EH_FRAME_ENTRY 6
405 . {* Nonzero if this section uses RELA relocations, rather than REL. *}
406 . unsigned int use_rela_p:1;
408 . {* Bits used by various backends. The generic code doesn't touch
411 . unsigned int sec_flg0:1;
412 . unsigned int sec_flg1:1;
413 . unsigned int sec_flg2:1;
414 . unsigned int sec_flg3:1;
415 . unsigned int sec_flg4:1;
416 . unsigned int sec_flg5:1;
418 . {* End of internal packed boolean fields. *}
420 . {* The virtual memory address of the section - where it will be
421 . at run time. The symbols are relocated against this. The
422 . user_set_vma flag is maintained by bfd; if it's not set, the
423 . backend can assign addresses (for example, in <<a.out>>, where
424 . the default address for <<.data>> is dependent on the specific
425 . target and various flags). *}
428 . {* The load address of the section - where it would be in a
429 . rom image; really only used for writing section header
433 . {* The size of the section in *octets*, as it will be output.
434 . Contains a value even if the section has no contents (e.g., the
435 . size of <<.bss>>). *}
436 . bfd_size_type size;
438 . {* For input sections, the original size on disk of the section, in
439 . octets. This field should be set for any section whose size is
440 . changed by linker relaxation. It is required for sections where
441 . the linker relaxation scheme doesn't cache altered section and
442 . reloc contents (stabs, eh_frame, SEC_MERGE, some coff relaxing
443 . targets), and thus the original size needs to be kept to read the
444 . section multiple times. For output sections, rawsize holds the
445 . section size calculated on a previous linker relaxation pass. *}
446 . bfd_size_type rawsize;
448 . {* The compressed size of the section in octets. *}
449 . bfd_size_type compressed_size;
451 . {* Relaxation table. *}
452 . struct relax_table *relax;
454 . {* Count of used relaxation table entries. *}
458 . {* If this section is going to be output, then this value is the
459 . offset in *bytes* into the output section of the first byte in the
460 . input section (byte ==> smallest addressable unit on the
461 . target). In most cases, if this was going to start at the
462 . 100th octet (8-bit quantity) in the output section, this value
463 . would be 100. However, if the target byte size is 16 bits
464 . (bfd_octets_per_byte is "2"), this value would be 50. *}
465 . bfd_vma output_offset;
467 . {* The output section through which to map on output. *}
468 . struct bfd_section *output_section;
470 . {* The alignment requirement of the section, as an exponent of 2 -
471 . e.g., 3 aligns to 2^3 (or 8). *}
472 . unsigned int alignment_power;
474 . {* If an input section, a pointer to a vector of relocation
475 . records for the data in this section. *}
476 . struct reloc_cache_entry *relocation;
478 . {* If an output section, a pointer to a vector of pointers to
479 . relocation records for the data in this section. *}
480 . struct reloc_cache_entry **orelocation;
482 . {* The number of relocation records in one of the above. *}
483 . unsigned reloc_count;
485 . {* Information below is back end specific - and not always used
488 . {* File position of section data. *}
491 . {* File position of relocation info. *}
492 . file_ptr rel_filepos;
494 . {* File position of line data. *}
495 . file_ptr line_filepos;
497 . {* Pointer to data for applications. *}
500 . {* If the SEC_IN_MEMORY flag is set, this points to the actual
502 . unsigned char *contents;
504 . {* Attached line number information. *}
507 . {* Number of line number records. *}
508 . unsigned int lineno_count;
510 . {* Entity size for merging purposes. *}
511 . unsigned int entsize;
513 . {* Points to the kept section if this section is a link-once section,
514 . and is discarded. *}
515 . struct bfd_section *kept_section;
517 . {* When a section is being output, this value changes as more
518 . linenumbers are written out. *}
519 . file_ptr moving_line_filepos;
521 . {* What the section number is in the target world. *}
526 . {* If this is a constructor section then here is a list of the
527 . relocations created to relocate items within it. *}
528 . struct relent_chain *constructor_chain;
530 . {* The BFD which owns the section. *}
533 . {* A symbol which points at this section only. *}
534 . struct bfd_symbol *symbol;
535 . struct bfd_symbol **symbol_ptr_ptr;
537 . {* Early in the link process, map_head and map_tail are used to build
538 . a list of input sections attached to an output section. Later,
539 . output sections use these fields for a list of bfd_link_order
542 . struct bfd_link_order *link_order;
543 . struct bfd_section *s;
544 . } map_head, map_tail;
547 .{* Relax table contains information about instructions which can
548 . be removed by relaxation -- replacing a long address with a
550 .struct relax_table {
551 . {* Address where bytes may be deleted. *}
554 . {* Number of bytes to be deleted. *}
558 .{* Note: the following are provided as inline functions rather than macros
559 . because not all callers use the return value. A macro implementation
560 . would use a comma expression, eg: "((ptr)->foo = val, TRUE)" and some
561 . compilers will complain about comma expressions that have no effect. *}
562 .static inline bfd_boolean
563 .bfd_set_section_userdata (bfd * abfd ATTRIBUTE_UNUSED, asection * ptr,
566 . ptr->userdata = val;
570 .static inline bfd_boolean
571 .bfd_set_section_vma (bfd * abfd ATTRIBUTE_UNUSED, asection * ptr, bfd_vma val)
573 . ptr->vma = ptr->lma = val;
574 . ptr->user_set_vma = TRUE;
578 .static inline bfd_boolean
579 .bfd_set_section_alignment (bfd * abfd ATTRIBUTE_UNUSED, asection * ptr,
582 . ptr->alignment_power = val;
586 .{* These sections are global, and are managed by BFD. The application
587 . and target back end are not permitted to change the values in
589 .extern asection _bfd_std_section[4];
591 .#define BFD_ABS_SECTION_NAME "*ABS*"
592 .#define BFD_UND_SECTION_NAME "*UND*"
593 .#define BFD_COM_SECTION_NAME "*COM*"
594 .#define BFD_IND_SECTION_NAME "*IND*"
596 .{* Pointer to the common section. *}
597 .#define bfd_com_section_ptr (&_bfd_std_section[0])
598 .{* Pointer to the undefined section. *}
599 .#define bfd_und_section_ptr (&_bfd_std_section[1])
600 .{* Pointer to the absolute section. *}
601 .#define bfd_abs_section_ptr (&_bfd_std_section[2])
602 .{* Pointer to the indirect section. *}
603 .#define bfd_ind_section_ptr (&_bfd_std_section[3])
605 .#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr)
606 .#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr)
607 .#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr)
609 .#define bfd_is_const_section(SEC) \
610 . ( ((SEC) == bfd_abs_section_ptr) \
611 . || ((SEC) == bfd_und_section_ptr) \
612 . || ((SEC) == bfd_com_section_ptr) \
613 . || ((SEC) == bfd_ind_section_ptr))
615 .{* Macros to handle insertion and deletion of a bfd's sections. These
616 . only handle the list pointers, ie. do not adjust section_count,
617 . target_index etc. *}
618 .#define bfd_section_list_remove(ABFD, S) \
621 . asection *_s = S; \
622 . asection *_next = _s->next; \
623 . asection *_prev = _s->prev; \
625 . _prev->next = _next; \
627 . (ABFD)->sections = _next; \
629 . _next->prev = _prev; \
631 . (ABFD)->section_last = _prev; \
634 .#define bfd_section_list_append(ABFD, S) \
637 . asection *_s = S; \
638 . bfd *_abfd = ABFD; \
640 . if (_abfd->section_last) \
642 . _s->prev = _abfd->section_last; \
643 . _abfd->section_last->next = _s; \
648 . _abfd->sections = _s; \
650 . _abfd->section_last = _s; \
653 .#define bfd_section_list_prepend(ABFD, S) \
656 . asection *_s = S; \
657 . bfd *_abfd = ABFD; \
659 . if (_abfd->sections) \
661 . _s->next = _abfd->sections; \
662 . _abfd->sections->prev = _s; \
667 . _abfd->section_last = _s; \
669 . _abfd->sections = _s; \
672 .#define bfd_section_list_insert_after(ABFD, A, S) \
675 . asection *_a = A; \
676 . asection *_s = S; \
677 . asection *_next = _a->next; \
678 . _s->next = _next; \
682 . _next->prev = _s; \
684 . (ABFD)->section_last = _s; \
687 .#define bfd_section_list_insert_before(ABFD, B, S) \
690 . asection *_b = B; \
691 . asection *_s = S; \
692 . asection *_prev = _b->prev; \
693 . _s->prev = _prev; \
697 . _prev->next = _s; \
699 . (ABFD)->sections = _s; \
702 .#define bfd_section_removed_from_list(ABFD, S) \
703 . ((S)->next == NULL ? (ABFD)->section_last != (S) : (S)->next->prev != (S))
705 .#define BFD_FAKE_SECTION(SEC, SYM, NAME, IDX, FLAGS) \
706 . {* name, id, index, next, prev, flags, user_set_vma, *} \
707 . { NAME, IDX, 0, NULL, NULL, FLAGS, 0, \
709 . {* linker_mark, linker_has_input, gc_mark, decompress_status, *} \
712 . {* segment_mark, sec_info_type, use_rela_p, *} \
715 . {* sec_flg0, sec_flg1, sec_flg2, sec_flg3, sec_flg4, sec_flg5, *} \
716 . 0, 0, 0, 0, 0, 0, \
718 . {* vma, lma, size, rawsize, compressed_size, relax, relax_count, *} \
719 . 0, 0, 0, 0, 0, 0, 0, \
721 . {* output_offset, output_section, alignment_power, *} \
724 . {* relocation, orelocation, reloc_count, filepos, rel_filepos, *} \
725 . NULL, NULL, 0, 0, 0, \
727 . {* line_filepos, userdata, contents, lineno, lineno_count, *} \
728 . 0, NULL, NULL, NULL, 0, \
730 . {* entsize, kept_section, moving_line_filepos, *} \
733 . {* target_index, used_by_bfd, constructor_chain, owner, *} \
734 . 0, NULL, NULL, NULL, \
736 . {* symbol, symbol_ptr_ptr, *} \
737 . (struct bfd_symbol *) SYM, &SEC.symbol, \
739 . {* map_head, map_tail *} \
740 . { NULL }, { NULL } \
743 .{* We use a macro to initialize the static asymbol structures because
744 . traditional C does not permit us to initialize a union member while
745 . gcc warns if we don't initialize it.
746 . the_bfd, name, value, attr, section [, udata] *}
748 .#define GLOBAL_SYM_INIT(NAME, SECTION) \
749 . { 0, NAME, 0, BSF_SECTION_SYM, SECTION, { 0 }}
751 .#define GLOBAL_SYM_INIT(NAME, SECTION) \
752 . { 0, NAME, 0, BSF_SECTION_SYM, SECTION }
757 /* These symbols are global, not specific to any BFD. Therefore, anything
758 that tries to change them is broken, and should be repaired. */
760 static const asymbol global_syms
[] =
762 GLOBAL_SYM_INIT (BFD_COM_SECTION_NAME
, bfd_com_section_ptr
),
763 GLOBAL_SYM_INIT (BFD_UND_SECTION_NAME
, bfd_und_section_ptr
),
764 GLOBAL_SYM_INIT (BFD_ABS_SECTION_NAME
, bfd_abs_section_ptr
),
765 GLOBAL_SYM_INIT (BFD_IND_SECTION_NAME
, bfd_ind_section_ptr
)
768 #define STD_SECTION(NAME, IDX, FLAGS) \
769 BFD_FAKE_SECTION(_bfd_std_section[IDX], &global_syms[IDX], NAME, IDX, FLAGS)
771 asection _bfd_std_section
[] = {
772 STD_SECTION (BFD_COM_SECTION_NAME
, 0, SEC_IS_COMMON
),
773 STD_SECTION (BFD_UND_SECTION_NAME
, 1, 0),
774 STD_SECTION (BFD_ABS_SECTION_NAME
, 2, 0),
775 STD_SECTION (BFD_IND_SECTION_NAME
, 3, 0)
779 /* Initialize an entry in the section hash table. */
781 struct bfd_hash_entry
*
782 bfd_section_hash_newfunc (struct bfd_hash_entry
*entry
,
783 struct bfd_hash_table
*table
,
786 /* Allocate the structure if it has not already been allocated by a
790 entry
= (struct bfd_hash_entry
*)
791 bfd_hash_allocate (table
, sizeof (struct section_hash_entry
));
796 /* Call the allocation method of the superclass. */
797 entry
= bfd_hash_newfunc (entry
, table
, string
);
799 memset (&((struct section_hash_entry
*) entry
)->section
, 0,
805 #define section_hash_lookup(table, string, create, copy) \
806 ((struct section_hash_entry *) \
807 bfd_hash_lookup ((table), (string), (create), (copy)))
809 /* Create a symbol whose only job is to point to this section. This
810 is useful for things like relocs which are relative to the base
814 _bfd_generic_new_section_hook (bfd
*abfd
, asection
*newsect
)
816 newsect
->symbol
= bfd_make_empty_symbol (abfd
);
817 if (newsect
->symbol
== NULL
)
820 newsect
->symbol
->name
= newsect
->name
;
821 newsect
->symbol
->value
= 0;
822 newsect
->symbol
->section
= newsect
;
823 newsect
->symbol
->flags
= BSF_SECTION_SYM
;
825 newsect
->symbol_ptr_ptr
= &newsect
->symbol
;
829 static unsigned int section_id
= 0x10; /* id 0 to 3 used by STD_SECTION. */
831 /* Initializes a new section. NEWSECT->NAME is already set. */
834 bfd_section_init (bfd
*abfd
, asection
*newsect
)
836 newsect
->id
= section_id
;
837 newsect
->index
= abfd
->section_count
;
838 newsect
->owner
= abfd
;
840 if (! BFD_SEND (abfd
, _new_section_hook
, (abfd
, newsect
)))
844 abfd
->section_count
++;
845 bfd_section_list_append (abfd
, newsect
);
852 section prototypes, , typedef asection, Sections
856 These are the functions exported by the section handling part of BFD.
861 bfd_section_list_clear
864 void bfd_section_list_clear (bfd *);
867 Clears the section list, and also resets the section count and
872 bfd_section_list_clear (bfd
*abfd
)
874 abfd
->sections
= NULL
;
875 abfd
->section_last
= NULL
;
876 abfd
->section_count
= 0;
877 memset (abfd
->section_htab
.table
, 0,
878 abfd
->section_htab
.size
* sizeof (struct bfd_hash_entry
*));
879 abfd
->section_htab
.count
= 0;
884 bfd_get_section_by_name
887 asection *bfd_get_section_by_name (bfd *abfd, const char *name);
890 Return the most recently created section attached to @var{abfd}
891 named @var{name}. Return NULL if no such section exists.
895 bfd_get_section_by_name (bfd
*abfd
, const char *name
)
897 struct section_hash_entry
*sh
;
899 sh
= section_hash_lookup (&abfd
->section_htab
, name
, FALSE
, FALSE
);
908 bfd_get_next_section_by_name
911 asection *bfd_get_next_section_by_name (bfd *ibfd, asection *sec);
914 Given @var{sec} is a section returned by @code{bfd_get_section_by_name},
915 return the next most recently created section attached to the same
916 BFD with the same name, or if no such section exists in the same BFD and
917 IBFD is non-NULL, the next section with the same name in any input
918 BFD following IBFD. Return NULL on finding no section.
922 bfd_get_next_section_by_name (bfd
*ibfd
, asection
*sec
)
924 struct section_hash_entry
*sh
;
928 sh
= ((struct section_hash_entry
*)
929 ((char *) sec
- offsetof (struct section_hash_entry
, section
)));
931 hash
= sh
->root
.hash
;
933 for (sh
= (struct section_hash_entry
*) sh
->root
.next
;
935 sh
= (struct section_hash_entry
*) sh
->root
.next
)
936 if (sh
->root
.hash
== hash
937 && strcmp (sh
->root
.string
, name
) == 0)
942 while ((ibfd
= ibfd
->link
.next
) != NULL
)
944 asection
*s
= bfd_get_section_by_name (ibfd
, name
);
955 bfd_get_linker_section
958 asection *bfd_get_linker_section (bfd *abfd, const char *name);
961 Return the linker created section attached to @var{abfd}
962 named @var{name}. Return NULL if no such section exists.
966 bfd_get_linker_section (bfd
*abfd
, const char *name
)
968 asection
*sec
= bfd_get_section_by_name (abfd
, name
);
970 while (sec
!= NULL
&& (sec
->flags
& SEC_LINKER_CREATED
) == 0)
971 sec
= bfd_get_next_section_by_name (NULL
, sec
);
977 bfd_get_section_by_name_if
980 asection *bfd_get_section_by_name_if
983 bfd_boolean (*func) (bfd *abfd, asection *sect, void *obj),
987 Call the provided function @var{func} for each section
988 attached to the BFD @var{abfd} whose name matches @var{name},
989 passing @var{obj} as an argument. The function will be called
992 | func (abfd, the_section, obj);
994 It returns the first section for which @var{func} returns true,
1000 bfd_get_section_by_name_if (bfd
*abfd
, const char *name
,
1001 bfd_boolean (*operation
) (bfd
*,
1006 struct section_hash_entry
*sh
;
1009 sh
= section_hash_lookup (&abfd
->section_htab
, name
, FALSE
, FALSE
);
1013 hash
= sh
->root
.hash
;
1014 for (; sh
!= NULL
; sh
= (struct section_hash_entry
*) sh
->root
.next
)
1015 if (sh
->root
.hash
== hash
1016 && strcmp (sh
->root
.string
, name
) == 0
1017 && (*operation
) (abfd
, &sh
->section
, user_storage
))
1018 return &sh
->section
;
1025 bfd_get_unique_section_name
1028 char *bfd_get_unique_section_name
1029 (bfd *abfd, const char *templat, int *count);
1032 Invent a section name that is unique in @var{abfd} by tacking
1033 a dot and a digit suffix onto the original @var{templat}. If
1034 @var{count} is non-NULL, then it specifies the first number
1035 tried as a suffix to generate a unique name. The value
1036 pointed to by @var{count} will be incremented in this case.
1040 bfd_get_unique_section_name (bfd
*abfd
, const char *templat
, int *count
)
1046 len
= strlen (templat
);
1047 sname
= (char *) bfd_malloc (len
+ 8);
1050 memcpy (sname
, templat
, len
);
1057 /* If we have a million sections, something is badly wrong. */
1060 sprintf (sname
+ len
, ".%d", num
++);
1062 while (section_hash_lookup (&abfd
->section_htab
, sname
, FALSE
, FALSE
));
1071 bfd_make_section_old_way
1074 asection *bfd_make_section_old_way (bfd *abfd, const char *name);
1077 Create a new empty section called @var{name}
1078 and attach it to the end of the chain of sections for the
1079 BFD @var{abfd}. An attempt to create a section with a name which
1080 is already in use returns its pointer without changing the
1083 It has the funny name since this is the way it used to be
1084 before it was rewritten....
1086 Possible errors are:
1087 o <<bfd_error_invalid_operation>> -
1088 If output has already started for this BFD.
1089 o <<bfd_error_no_memory>> -
1090 If memory allocation fails.
1095 bfd_make_section_old_way (bfd
*abfd
, const char *name
)
1099 if (abfd
->output_has_begun
)
1101 bfd_set_error (bfd_error_invalid_operation
);
1105 if (strcmp (name
, BFD_ABS_SECTION_NAME
) == 0)
1106 newsect
= bfd_abs_section_ptr
;
1107 else if (strcmp (name
, BFD_COM_SECTION_NAME
) == 0)
1108 newsect
= bfd_com_section_ptr
;
1109 else if (strcmp (name
, BFD_UND_SECTION_NAME
) == 0)
1110 newsect
= bfd_und_section_ptr
;
1111 else if (strcmp (name
, BFD_IND_SECTION_NAME
) == 0)
1112 newsect
= bfd_ind_section_ptr
;
1115 struct section_hash_entry
*sh
;
1117 sh
= section_hash_lookup (&abfd
->section_htab
, name
, TRUE
, FALSE
);
1121 newsect
= &sh
->section
;
1122 if (newsect
->name
!= NULL
)
1124 /* Section already exists. */
1128 newsect
->name
= name
;
1129 return bfd_section_init (abfd
, newsect
);
1132 /* Call new_section_hook when "creating" the standard abs, com, und
1133 and ind sections to tack on format specific section data.
1134 Also, create a proper section symbol. */
1135 if (! BFD_SEND (abfd
, _new_section_hook
, (abfd
, newsect
)))
1142 bfd_make_section_anyway_with_flags
1145 asection *bfd_make_section_anyway_with_flags
1146 (bfd *abfd, const char *name, flagword flags);
1149 Create a new empty section called @var{name} and attach it to the end of
1150 the chain of sections for @var{abfd}. Create a new section even if there
1151 is already a section with that name. Also set the attributes of the
1152 new section to the value @var{flags}.
1154 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
1155 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
1156 o <<bfd_error_no_memory>> - If memory allocation fails.
1160 bfd_make_section_anyway_with_flags (bfd
*abfd
, const char *name
,
1163 struct section_hash_entry
*sh
;
1166 if (abfd
->output_has_begun
)
1168 bfd_set_error (bfd_error_invalid_operation
);
1172 sh
= section_hash_lookup (&abfd
->section_htab
, name
, TRUE
, FALSE
);
1176 newsect
= &sh
->section
;
1177 if (newsect
->name
!= NULL
)
1179 /* We are making a section of the same name. Put it in the
1180 section hash table. Even though we can't find it directly by a
1181 hash lookup, we'll be able to find the section by traversing
1182 sh->root.next quicker than looking at all the bfd sections. */
1183 struct section_hash_entry
*new_sh
;
1184 new_sh
= (struct section_hash_entry
*)
1185 bfd_section_hash_newfunc (NULL
, &abfd
->section_htab
, name
);
1189 new_sh
->root
= sh
->root
;
1190 sh
->root
.next
= &new_sh
->root
;
1191 newsect
= &new_sh
->section
;
1194 newsect
->flags
= flags
;
1195 newsect
->name
= name
;
1196 return bfd_section_init (abfd
, newsect
);
1201 bfd_make_section_anyway
1204 asection *bfd_make_section_anyway (bfd *abfd, const char *name);
1207 Create a new empty section called @var{name} and attach it to the end of
1208 the chain of sections for @var{abfd}. Create a new section even if there
1209 is already a section with that name.
1211 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
1212 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
1213 o <<bfd_error_no_memory>> - If memory allocation fails.
1217 bfd_make_section_anyway (bfd
*abfd
, const char *name
)
1219 return bfd_make_section_anyway_with_flags (abfd
, name
, 0);
1224 bfd_make_section_with_flags
1227 asection *bfd_make_section_with_flags
1228 (bfd *, const char *name, flagword flags);
1231 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
1232 bfd_set_error ()) without changing the section chain if there is already a
1233 section named @var{name}. Also set the attributes of the new section to
1234 the value @var{flags}. If there is an error, return <<NULL>> and set
1239 bfd_make_section_with_flags (bfd
*abfd
, const char *name
,
1242 struct section_hash_entry
*sh
;
1245 if (abfd
== NULL
|| name
== NULL
|| abfd
->output_has_begun
)
1247 bfd_set_error (bfd_error_invalid_operation
);
1251 if (strcmp (name
, BFD_ABS_SECTION_NAME
) == 0
1252 || strcmp (name
, BFD_COM_SECTION_NAME
) == 0
1253 || strcmp (name
, BFD_UND_SECTION_NAME
) == 0
1254 || strcmp (name
, BFD_IND_SECTION_NAME
) == 0)
1257 sh
= section_hash_lookup (&abfd
->section_htab
, name
, TRUE
, FALSE
);
1261 newsect
= &sh
->section
;
1262 if (newsect
->name
!= NULL
)
1264 /* Section already exists. */
1268 newsect
->name
= name
;
1269 newsect
->flags
= flags
;
1270 return bfd_section_init (abfd
, newsect
);
1278 asection *bfd_make_section (bfd *, const char *name);
1281 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
1282 bfd_set_error ()) without changing the section chain if there is already a
1283 section named @var{name}. If there is an error, return <<NULL>> and set
1288 bfd_make_section (bfd
*abfd
, const char *name
)
1290 return bfd_make_section_with_flags (abfd
, name
, 0);
1295 bfd_get_next_section_id
1298 int bfd_get_next_section_id (void);
1301 Returns the id that the next section created will have.
1305 bfd_get_next_section_id (void)
1312 bfd_set_section_flags
1315 bfd_boolean bfd_set_section_flags
1316 (bfd *abfd, asection *sec, flagword flags);
1319 Set the attributes of the section @var{sec} in the BFD
1320 @var{abfd} to the value @var{flags}. Return <<TRUE>> on success,
1321 <<FALSE>> on error. Possible error returns are:
1323 o <<bfd_error_invalid_operation>> -
1324 The section cannot have one or more of the attributes
1325 requested. For example, a .bss section in <<a.out>> may not
1326 have the <<SEC_HAS_CONTENTS>> field set.
1331 bfd_set_section_flags (bfd
*abfd ATTRIBUTE_UNUSED
,
1335 section
->flags
= flags
;
1344 void bfd_rename_section
1345 (bfd *abfd, asection *sec, const char *newname);
1348 Rename section @var{sec} in @var{abfd} to @var{newname}.
1352 bfd_rename_section (bfd
*abfd
, sec_ptr sec
, const char *newname
)
1354 struct section_hash_entry
*sh
;
1356 sh
= (struct section_hash_entry
*)
1357 ((char *) sec
- offsetof (struct section_hash_entry
, section
));
1358 sh
->section
.name
= newname
;
1359 bfd_hash_rename (&abfd
->section_htab
, newname
, &sh
->root
);
1364 bfd_map_over_sections
1367 void bfd_map_over_sections
1369 void (*func) (bfd *abfd, asection *sect, void *obj),
1373 Call the provided function @var{func} for each section
1374 attached to the BFD @var{abfd}, passing @var{obj} as an
1375 argument. The function will be called as if by
1377 | func (abfd, the_section, obj);
1379 This is the preferred method for iterating over sections; an
1380 alternative would be to use a loop:
1383 | for (p = abfd->sections; p != NULL; p = p->next)
1384 | func (abfd, p, ...)
1389 bfd_map_over_sections (bfd
*abfd
,
1390 void (*operation
) (bfd
*, asection
*, void *),
1396 for (sect
= abfd
->sections
; sect
!= NULL
; i
++, sect
= sect
->next
)
1397 (*operation
) (abfd
, sect
, user_storage
);
1399 if (i
!= abfd
->section_count
) /* Debugging */
1405 bfd_sections_find_if
1408 asection *bfd_sections_find_if
1410 bfd_boolean (*operation) (bfd *abfd, asection *sect, void *obj),
1414 Call the provided function @var{operation} for each section
1415 attached to the BFD @var{abfd}, passing @var{obj} as an
1416 argument. The function will be called as if by
1418 | operation (abfd, the_section, obj);
1420 It returns the first section for which @var{operation} returns true.
1425 bfd_sections_find_if (bfd
*abfd
,
1426 bfd_boolean (*operation
) (bfd
*, asection
*, void *),
1431 for (sect
= abfd
->sections
; sect
!= NULL
; sect
= sect
->next
)
1432 if ((*operation
) (abfd
, sect
, user_storage
))
1440 bfd_set_section_size
1443 bfd_boolean bfd_set_section_size
1444 (bfd *abfd, asection *sec, bfd_size_type val);
1447 Set @var{sec} to the size @var{val}. If the operation is
1448 ok, then <<TRUE>> is returned, else <<FALSE>>.
1450 Possible error returns:
1451 o <<bfd_error_invalid_operation>> -
1452 Writing has started to the BFD, so setting the size is invalid.
1457 bfd_set_section_size (bfd
*abfd
, sec_ptr ptr
, bfd_size_type val
)
1459 /* Once you've started writing to any section you cannot create or change
1460 the size of any others. */
1462 if (abfd
->output_has_begun
)
1464 bfd_set_error (bfd_error_invalid_operation
);
1474 bfd_set_section_contents
1477 bfd_boolean bfd_set_section_contents
1478 (bfd *abfd, asection *section, const void *data,
1479 file_ptr offset, bfd_size_type count);
1482 Sets the contents of the section @var{section} in BFD
1483 @var{abfd} to the data starting in memory at @var{data}. The
1484 data is written to the output section starting at offset
1485 @var{offset} for @var{count} octets.
1487 Normally <<TRUE>> is returned, else <<FALSE>>. Possible error
1489 o <<bfd_error_no_contents>> -
1490 The output section does not have the <<SEC_HAS_CONTENTS>>
1491 attribute, so nothing can be written to it.
1494 This routine is front end to the back end function
1495 <<_bfd_set_section_contents>>.
1500 bfd_set_section_contents (bfd
*abfd
,
1502 const void *location
,
1504 bfd_size_type count
)
1508 if (!(bfd_get_section_flags (abfd
, section
) & SEC_HAS_CONTENTS
))
1510 bfd_set_error (bfd_error_no_contents
);
1515 if ((bfd_size_type
) offset
> sz
1517 || offset
+ count
> sz
1518 || count
!= (size_t) count
)
1520 bfd_set_error (bfd_error_bad_value
);
1524 if (!bfd_write_p (abfd
))
1526 bfd_set_error (bfd_error_invalid_operation
);
1530 /* Record a copy of the data in memory if desired. */
1531 if (section
->contents
1532 && location
!= section
->contents
+ offset
)
1533 memcpy (section
->contents
+ offset
, location
, (size_t) count
);
1535 if (BFD_SEND (abfd
, _bfd_set_section_contents
,
1536 (abfd
, section
, location
, offset
, count
)))
1538 abfd
->output_has_begun
= TRUE
;
1547 bfd_get_section_contents
1550 bfd_boolean bfd_get_section_contents
1551 (bfd *abfd, asection *section, void *location, file_ptr offset,
1552 bfd_size_type count);
1555 Read data from @var{section} in BFD @var{abfd}
1556 into memory starting at @var{location}. The data is read at an
1557 offset of @var{offset} from the start of the input section,
1558 and is read for @var{count} bytes.
1560 If the contents of a constructor with the <<SEC_CONSTRUCTOR>>
1561 flag set are requested or if the section does not have the
1562 <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled
1563 with zeroes. If no errors occur, <<TRUE>> is returned, else
1568 bfd_get_section_contents (bfd
*abfd
,
1572 bfd_size_type count
)
1576 if (section
->flags
& SEC_CONSTRUCTOR
)
1578 memset (location
, 0, (size_t) count
);
1582 if (abfd
->direction
!= write_direction
&& section
->rawsize
!= 0)
1583 sz
= section
->rawsize
;
1586 if ((bfd_size_type
) offset
> sz
1588 || offset
+ count
> sz
1589 || count
!= (size_t) count
)
1591 bfd_set_error (bfd_error_bad_value
);
1599 if ((section
->flags
& SEC_HAS_CONTENTS
) == 0)
1601 memset (location
, 0, (size_t) count
);
1605 if ((section
->flags
& SEC_IN_MEMORY
) != 0)
1607 if (section
->contents
== NULL
)
1609 /* This can happen because of errors earlier on in the linking process.
1610 We do not want to seg-fault here, so clear the flag and return an
1612 section
->flags
&= ~ SEC_IN_MEMORY
;
1613 bfd_set_error (bfd_error_invalid_operation
);
1617 memmove (location
, section
->contents
+ offset
, (size_t) count
);
1621 return BFD_SEND (abfd
, _bfd_get_section_contents
,
1622 (abfd
, section
, location
, offset
, count
));
1627 bfd_malloc_and_get_section
1630 bfd_boolean bfd_malloc_and_get_section
1631 (bfd *abfd, asection *section, bfd_byte **buf);
1634 Read all data from @var{section} in BFD @var{abfd}
1635 into a buffer, *@var{buf}, malloc'd by this function.
1639 bfd_malloc_and_get_section (bfd
*abfd
, sec_ptr sec
, bfd_byte
**buf
)
1642 return bfd_get_full_section_contents (abfd
, sec
, buf
);
1646 bfd_copy_private_section_data
1649 bfd_boolean bfd_copy_private_section_data
1650 (bfd *ibfd, asection *isec, bfd *obfd, asection *osec);
1653 Copy private section information from @var{isec} in the BFD
1654 @var{ibfd} to the section @var{osec} in the BFD @var{obfd}.
1655 Return <<TRUE>> on success, <<FALSE>> on error. Possible error
1658 o <<bfd_error_no_memory>> -
1659 Not enough memory exists to create private data for @var{osec}.
1661 .#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \
1662 . BFD_SEND (obfd, _bfd_copy_private_section_data, \
1663 . (ibfd, isection, obfd, osection))
1668 bfd_generic_is_group_section
1671 bfd_boolean bfd_generic_is_group_section (bfd *, const asection *sec);
1674 Returns TRUE if @var{sec} is a member of a group.
1678 bfd_generic_is_group_section (bfd
*abfd ATTRIBUTE_UNUSED
,
1679 const asection
*sec ATTRIBUTE_UNUSED
)
1686 bfd_generic_discard_group
1689 bfd_boolean bfd_generic_discard_group (bfd *abfd, asection *group);
1692 Remove all members of @var{group} from the output.
1696 bfd_generic_discard_group (bfd
*abfd ATTRIBUTE_UNUSED
,
1697 asection
*group ATTRIBUTE_UNUSED
)