1 /* Object file "section" support for the BFD library.
2 Copyright (C) 1990-2015 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. *}
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 0x000
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 0x001
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 0x002
184 . {* The section contains data still to be relocated, so there is
185 . some relocation information too. *}
186 .#define SEC_RELOC 0x004
188 . {* A signal to the OS that the section contains read only data. *}
189 .#define SEC_READONLY 0x008
191 . {* The section contains code only. *}
192 .#define SEC_CODE 0x010
194 . {* The section contains data only. *}
195 .#define SEC_DATA 0x020
197 . {* The section will reside in ROM. *}
198 .#define SEC_ROM 0x040
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 0x080
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 . {* End of section flags. *}
366 . {* Some internal packed boolean fields. *}
368 . {* See the vma field. *}
369 . unsigned int user_set_vma : 1;
371 . {* A mark flag used by some of the linker backends. *}
372 . unsigned int linker_mark : 1;
374 . {* Another mark flag used by some of the linker backends. Set for
375 . output sections that have an input section. *}
376 . unsigned int linker_has_input : 1;
378 . {* Mark flag used by some linker backends for garbage collection. *}
379 . unsigned int gc_mark : 1;
381 . {* Section compression status. *}
382 . unsigned int compress_status : 2;
383 .#define COMPRESS_SECTION_NONE 0
384 .#define COMPRESS_SECTION_DONE 1
385 .#define DECOMPRESS_SECTION_SIZED 2
387 . {* The following flags are used by the ELF linker. *}
389 . {* Mark sections which have been allocated to segments. *}
390 . unsigned int segment_mark : 1;
392 . {* Type of sec_info information. *}
393 . unsigned int sec_info_type:3;
394 .#define SEC_INFO_TYPE_NONE 0
395 .#define SEC_INFO_TYPE_STABS 1
396 .#define SEC_INFO_TYPE_MERGE 2
397 .#define SEC_INFO_TYPE_EH_FRAME 3
398 .#define SEC_INFO_TYPE_JUST_SYMS 4
399 .#define SEC_INFO_TYPE_TARGET 5
401 . {* Nonzero if this section uses RELA relocations, rather than REL. *}
402 . unsigned int use_rela_p:1;
404 . {* Bits used by various backends. The generic code doesn't touch
407 . unsigned int sec_flg0:1;
408 . unsigned int sec_flg1:1;
409 . unsigned int sec_flg2:1;
410 . unsigned int sec_flg3:1;
411 . unsigned int sec_flg4:1;
412 . unsigned int sec_flg5:1;
414 . {* End of internal packed boolean fields. *}
416 . {* The virtual memory address of the section - where it will be
417 . at run time. The symbols are relocated against this. The
418 . user_set_vma flag is maintained by bfd; if it's not set, the
419 . backend can assign addresses (for example, in <<a.out>>, where
420 . the default address for <<.data>> is dependent on the specific
421 . target and various flags). *}
424 . {* The load address of the section - where it would be in a
425 . rom image; really only used for writing section header
429 . {* The size of the section in octets, as it will be output.
430 . Contains a value even if the section has no contents (e.g., the
431 . size of <<.bss>>). *}
432 . bfd_size_type size;
434 . {* For input sections, the original size on disk of the section, in
435 . octets. This field should be set for any section whose size is
436 . changed by linker relaxation. It is required for sections where
437 . the linker relaxation scheme doesn't cache altered section and
438 . reloc contents (stabs, eh_frame, SEC_MERGE, some coff relaxing
439 . targets), and thus the original size needs to be kept to read the
440 . section multiple times. For output sections, rawsize holds the
441 . section size calculated on a previous linker relaxation pass. *}
442 . bfd_size_type rawsize;
444 . {* The compressed size of the section in octets. *}
445 . bfd_size_type compressed_size;
447 . {* Relaxation table. *}
448 . struct relax_table *relax;
450 . {* Count of used relaxation table entries. *}
454 . {* If this section is going to be output, then this value is the
455 . offset in *bytes* into the output section of the first byte in the
456 . input section (byte ==> smallest addressable unit on the
457 . target). In most cases, if this was going to start at the
458 . 100th octet (8-bit quantity) in the output section, this value
459 . would be 100. However, if the target byte size is 16 bits
460 . (bfd_octets_per_byte is "2"), this value would be 50. *}
461 . bfd_vma output_offset;
463 . {* The output section through which to map on output. *}
464 . struct bfd_section *output_section;
466 . {* The alignment requirement of the section, as an exponent of 2 -
467 . e.g., 3 aligns to 2^3 (or 8). *}
468 . unsigned int alignment_power;
470 . {* If an input section, a pointer to a vector of relocation
471 . records for the data in this section. *}
472 . struct reloc_cache_entry *relocation;
474 . {* If an output section, a pointer to a vector of pointers to
475 . relocation records for the data in this section. *}
476 . struct reloc_cache_entry **orelocation;
478 . {* The number of relocation records in one of the above. *}
479 . unsigned reloc_count;
481 . {* Information below is back end specific - and not always used
484 . {* File position of section data. *}
487 . {* File position of relocation info. *}
488 . file_ptr rel_filepos;
490 . {* File position of line data. *}
491 . file_ptr line_filepos;
493 . {* Pointer to data for applications. *}
496 . {* If the SEC_IN_MEMORY flag is set, this points to the actual
498 . unsigned char *contents;
500 . {* Attached line number information. *}
503 . {* Number of line number records. *}
504 . unsigned int lineno_count;
506 . {* Entity size for merging purposes. *}
507 . unsigned int entsize;
509 . {* Points to the kept section if this section is a link-once section,
510 . and is discarded. *}
511 . struct bfd_section *kept_section;
513 . {* When a section is being output, this value changes as more
514 . linenumbers are written out. *}
515 . file_ptr moving_line_filepos;
517 . {* What the section number is in the target world. *}
522 . {* If this is a constructor section then here is a list of the
523 . relocations created to relocate items within it. *}
524 . struct relent_chain *constructor_chain;
526 . {* The BFD which owns the section. *}
529 . {* A symbol which points at this section only. *}
530 . struct bfd_symbol *symbol;
531 . struct bfd_symbol **symbol_ptr_ptr;
533 . {* Early in the link process, map_head and map_tail are used to build
534 . a list of input sections attached to an output section. Later,
535 . output sections use these fields for a list of bfd_link_order
538 . struct bfd_link_order *link_order;
539 . struct bfd_section *s;
540 . } map_head, map_tail;
543 .{* Relax table contains information about instructions which can
544 . be removed by relaxation -- replacing a long address with a
546 .struct relax_table {
547 . {* Address where bytes may be deleted. *}
550 . {* Number of bytes to be deleted. *}
554 .{* Note: the following are provided as inline functions rather than macros
555 . because not all callers use the return value. A macro implementation
556 . would use a comma expression, eg: "((ptr)->foo = val, TRUE)" and some
557 . compilers will complain about comma expressions that have no effect. *}
558 .static inline bfd_boolean
559 .bfd_set_section_userdata (bfd * abfd ATTRIBUTE_UNUSED, asection * ptr, void * val)
561 . ptr->userdata = val;
565 .static inline bfd_boolean
566 .bfd_set_section_vma (bfd * abfd ATTRIBUTE_UNUSED, asection * ptr, bfd_vma val)
568 . ptr->vma = ptr->lma = val;
569 . ptr->user_set_vma = TRUE;
573 .static inline bfd_boolean
574 .bfd_set_section_alignment (bfd * abfd ATTRIBUTE_UNUSED, asection * ptr, unsigned int val)
576 . ptr->alignment_power = val;
580 .{* These sections are global, and are managed by BFD. The application
581 . and target back end are not permitted to change the values in
583 .extern asection _bfd_std_section[4];
585 .#define BFD_ABS_SECTION_NAME "*ABS*"
586 .#define BFD_UND_SECTION_NAME "*UND*"
587 .#define BFD_COM_SECTION_NAME "*COM*"
588 .#define BFD_IND_SECTION_NAME "*IND*"
590 .{* Pointer to the common section. *}
591 .#define bfd_com_section_ptr (&_bfd_std_section[0])
592 .{* Pointer to the undefined section. *}
593 .#define bfd_und_section_ptr (&_bfd_std_section[1])
594 .{* Pointer to the absolute section. *}
595 .#define bfd_abs_section_ptr (&_bfd_std_section[2])
596 .{* Pointer to the indirect section. *}
597 .#define bfd_ind_section_ptr (&_bfd_std_section[3])
599 .#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr)
600 .#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr)
601 .#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr)
603 .#define bfd_is_const_section(SEC) \
604 . ( ((SEC) == bfd_abs_section_ptr) \
605 . || ((SEC) == bfd_und_section_ptr) \
606 . || ((SEC) == bfd_com_section_ptr) \
607 . || ((SEC) == bfd_ind_section_ptr))
609 .{* Macros to handle insertion and deletion of a bfd's sections. These
610 . only handle the list pointers, ie. do not adjust section_count,
611 . target_index etc. *}
612 .#define bfd_section_list_remove(ABFD, S) \
615 . asection *_s = S; \
616 . asection *_next = _s->next; \
617 . asection *_prev = _s->prev; \
619 . _prev->next = _next; \
621 . (ABFD)->sections = _next; \
623 . _next->prev = _prev; \
625 . (ABFD)->section_last = _prev; \
628 .#define bfd_section_list_append(ABFD, S) \
631 . asection *_s = S; \
632 . bfd *_abfd = ABFD; \
634 . if (_abfd->section_last) \
636 . _s->prev = _abfd->section_last; \
637 . _abfd->section_last->next = _s; \
642 . _abfd->sections = _s; \
644 . _abfd->section_last = _s; \
647 .#define bfd_section_list_prepend(ABFD, S) \
650 . asection *_s = S; \
651 . bfd *_abfd = ABFD; \
653 . if (_abfd->sections) \
655 . _s->next = _abfd->sections; \
656 . _abfd->sections->prev = _s; \
661 . _abfd->section_last = _s; \
663 . _abfd->sections = _s; \
666 .#define bfd_section_list_insert_after(ABFD, A, S) \
669 . asection *_a = A; \
670 . asection *_s = S; \
671 . asection *_next = _a->next; \
672 . _s->next = _next; \
676 . _next->prev = _s; \
678 . (ABFD)->section_last = _s; \
681 .#define bfd_section_list_insert_before(ABFD, B, S) \
684 . asection *_b = B; \
685 . asection *_s = S; \
686 . asection *_prev = _b->prev; \
687 . _s->prev = _prev; \
691 . _prev->next = _s; \
693 . (ABFD)->sections = _s; \
696 .#define bfd_section_removed_from_list(ABFD, S) \
697 . ((S)->next == NULL ? (ABFD)->section_last != (S) : (S)->next->prev != (S))
699 .#define BFD_FAKE_SECTION(SEC, FLAGS, SYM, NAME, IDX) \
700 . {* name, id, index, next, prev, flags, user_set_vma, *} \
701 . { NAME, IDX, 0, NULL, NULL, FLAGS, 0, \
703 . {* linker_mark, linker_has_input, gc_mark, decompress_status, *} \
706 . {* segment_mark, sec_info_type, use_rela_p, *} \
709 . {* sec_flg0, sec_flg1, sec_flg2, sec_flg3, sec_flg4, sec_flg5, *} \
710 . 0, 0, 0, 0, 0, 0, \
712 . {* vma, lma, size, rawsize, compressed_size, relax, relax_count, *} \
713 . 0, 0, 0, 0, 0, 0, 0, \
715 . {* output_offset, output_section, alignment_power, *} \
718 . {* relocation, orelocation, reloc_count, filepos, rel_filepos, *} \
719 . NULL, NULL, 0, 0, 0, \
721 . {* line_filepos, userdata, contents, lineno, lineno_count, *} \
722 . 0, NULL, NULL, NULL, 0, \
724 . {* entsize, kept_section, moving_line_filepos, *} \
727 . {* target_index, used_by_bfd, constructor_chain, owner, *} \
728 . 0, NULL, NULL, NULL, \
730 . {* symbol, symbol_ptr_ptr, *} \
731 . (struct bfd_symbol *) SYM, &SEC.symbol, \
733 . {* map_head, map_tail *} \
734 . { NULL }, { NULL } \
739 /* We use a macro to initialize the static asymbol structures because
740 traditional C does not permit us to initialize a union member while
741 gcc warns if we don't initialize it. */
742 /* the_bfd, name, value, attr, section [, udata] */
744 #define GLOBAL_SYM_INIT(NAME, SECTION) \
745 { 0, NAME, 0, BSF_SECTION_SYM, SECTION, { 0 }}
747 #define GLOBAL_SYM_INIT(NAME, SECTION) \
748 { 0, NAME, 0, BSF_SECTION_SYM, SECTION }
751 /* These symbols are global, not specific to any BFD. Therefore, anything
752 that tries to change them is broken, and should be repaired. */
754 static const asymbol global_syms[] =
756 GLOBAL_SYM_INIT (BFD_COM_SECTION_NAME, bfd_com_section_ptr),
757 GLOBAL_SYM_INIT (BFD_UND_SECTION_NAME, bfd_und_section_ptr),
758 GLOBAL_SYM_INIT (BFD_ABS_SECTION_NAME, bfd_abs_section_ptr),
759 GLOBAL_SYM_INIT (BFD_IND_SECTION_NAME, bfd_ind_section_ptr)
762 #define STD_SECTION(NAME, IDX, FLAGS) \
763 BFD_FAKE_SECTION(_bfd_std_section[IDX], FLAGS, &global_syms[IDX], NAME, IDX)
765 asection _bfd_std_section[] = {
766 STD_SECTION (BFD_COM_SECTION_NAME, 0, SEC_IS_COMMON),
767 STD_SECTION (BFD_UND_SECTION_NAME, 1, 0),
768 STD_SECTION (BFD_ABS_SECTION_NAME, 2, 0),
769 STD_SECTION (BFD_IND_SECTION_NAME, 3, 0)
773 /* Initialize an entry in the section hash table. */
775 struct bfd_hash_entry *
776 bfd_section_hash_newfunc (struct bfd_hash_entry *entry,
777 struct bfd_hash_table *table,
780 /* Allocate the structure if it has not already been allocated by a
784 entry = (struct bfd_hash_entry *)
785 bfd_hash_allocate (table, sizeof (struct section_hash_entry));
790 /* Call the allocation method of the superclass. */
791 entry = bfd_hash_newfunc (entry, table, string);
793 memset (&((struct section_hash_entry *) entry)->section, 0,
799 #define section_hash_lookup(table, string, create, copy) \
800 ((struct section_hash_entry *) \
801 bfd_hash_lookup ((table), (string), (create), (copy)))
803 /* Create a symbol whose only job is to point to this section. This
804 is useful for things like relocs which are relative to the base
808 _bfd_generic_new_section_hook (bfd *abfd, asection *newsect)
810 newsect->symbol = bfd_make_empty_symbol (abfd);
811 if (newsect->symbol == NULL)
814 newsect->symbol->name = newsect->name;
815 newsect->symbol->value = 0;
816 newsect->symbol->section = newsect;
817 newsect->symbol->flags = BSF_SECTION_SYM;
819 newsect->symbol_ptr_ptr = &newsect->symbol;
823 /* Initializes a new section. NEWSECT->NAME is already set. */
826 bfd_section_init (bfd *abfd, asection *newsect)
828 static int section_id = 0x10; /* id 0 to 3 used by STD_SECTION. */
830 newsect->id = section_id;
831 newsect->index = abfd->section_count;
832 newsect->owner = abfd;
834 if (! BFD_SEND (abfd, _new_section_hook, (abfd, newsect)))
838 abfd->section_count++;
839 bfd_section_list_append (abfd, newsect);
846 section prototypes, , typedef asection, Sections
850 These are the functions exported by the section handling part of BFD.
855 bfd_section_list_clear
858 void bfd_section_list_clear (bfd *);
861 Clears the section list, and also resets the section count and
866 bfd_section_list_clear (bfd *abfd)
868 abfd->sections = NULL;
869 abfd->section_last = NULL;
870 abfd->section_count = 0;
871 memset (abfd->section_htab.table, 0,
872 abfd->section_htab.size * sizeof (struct bfd_hash_entry *));
873 abfd->section_htab.count = 0;
878 bfd_get_section_by_name
881 asection *bfd_get_section_by_name (bfd *abfd, const char *name);
884 Return the most recently created section attached to @var{abfd}
885 named @var{name}. Return NULL if no such section exists.
889 bfd_get_section_by_name (bfd *abfd, const char *name)
891 struct section_hash_entry *sh;
893 sh = section_hash_lookup (&abfd->section_htab, name, FALSE, FALSE);
902 bfd_get_next_section_by_name
905 asection *bfd_get_next_section_by_name (asection *sec);
908 Given @var{sec} is a section returned by @code{bfd_get_section_by_name},
909 return the next most recently created section attached to the same
910 BFD with the same name. Return NULL if no such section exists.
914 bfd_get_next_section_by_name (asection *sec)
916 struct section_hash_entry *sh;
920 sh = ((struct section_hash_entry *)
921 ((char *) sec - offsetof (struct section_hash_entry, section)));
923 hash = sh->root.hash;
925 for (sh = (struct section_hash_entry *) sh->root.next;
927 sh = (struct section_hash_entry *) sh->root.next)
928 if (sh->root.hash == hash
929 && strcmp (sh->root.string, name) == 0)
937 bfd_get_linker_section
940 asection *bfd_get_linker_section (bfd *abfd, const char *name);
943 Return the linker created section attached to @var{abfd}
944 named @var{name}. Return NULL if no such section exists.
948 bfd_get_linker_section (bfd *abfd, const char *name)
950 asection *sec = bfd_get_section_by_name (abfd, name);
952 while (sec != NULL && (sec->flags & SEC_LINKER_CREATED) == 0)
953 sec = bfd_get_next_section_by_name (sec);
959 bfd_get_section_by_name_if
962 asection *bfd_get_section_by_name_if
965 bfd_boolean (*func) (bfd *abfd, asection *sect, void *obj),
969 Call the provided function @var{func} for each section
970 attached to the BFD @var{abfd} whose name matches @var{name},
971 passing @var{obj} as an argument. The function will be called
974 | func (abfd, the_section, obj);
976 It returns the first section for which @var{func} returns true,
982 bfd_get_section_by_name_if (bfd *abfd, const char *name,
983 bfd_boolean (*operation) (bfd *,
988 struct section_hash_entry *sh;
991 sh = section_hash_lookup (&abfd->section_htab, name, FALSE, FALSE);
995 hash = sh->root.hash;
998 if ((*operation) (abfd, &sh->section, user_storage))
1000 sh = (struct section_hash_entry *) sh->root.next;
1002 while (sh != NULL && sh->root.hash == hash
1003 && strcmp (sh->root.string, name) == 0);
1010 bfd_get_unique_section_name
1013 char *bfd_get_unique_section_name
1014 (bfd *abfd, const char *templat, int *count);
1017 Invent a section name that is unique in @var{abfd} by tacking
1018 a dot and a digit suffix onto the original @var{templat}. If
1019 @var{count} is non-NULL, then it specifies the first number
1020 tried as a suffix to generate a unique name. The value
1021 pointed to by @var{count} will be incremented in this case.
1025 bfd_get_unique_section_name (bfd *abfd, const char *templat, int *count)
1031 len = strlen (templat);
1032 sname = (char *) bfd_malloc (len + 8);
1035 memcpy (sname, templat, len);
1042 /* If we have a million sections, something is badly wrong. */
1045 sprintf (sname + len, ".%d", num++);
1047 while (section_hash_lookup (&abfd->section_htab, sname, FALSE, FALSE));
1056 bfd_make_section_old_way
1059 asection *bfd_make_section_old_way (bfd *abfd, const char *name);
1062 Create a new empty section called @var{name}
1063 and attach it to the end of the chain of sections for the
1064 BFD @var{abfd}. An attempt to create a section with a name which
1065 is already in use returns its pointer without changing the
1068 It has the funny name since this is the way it used to be
1069 before it was rewritten....
1071 Possible errors are:
1072 o <<bfd_error_invalid_operation>> -
1073 If output has already started for this BFD.
1074 o <<bfd_error_no_memory>> -
1075 If memory allocation fails.
1080 bfd_make_section_old_way (bfd *abfd, const char *name)
1084 if (abfd->output_has_begun)
1086 bfd_set_error (bfd_error_invalid_operation);
1090 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0)
1091 newsect = bfd_abs_section_ptr;
1092 else if (strcmp (name, BFD_COM_SECTION_NAME) == 0)
1093 newsect = bfd_com_section_ptr;
1094 else if (strcmp (name, BFD_UND_SECTION_NAME) == 0)
1095 newsect = bfd_und_section_ptr;
1096 else if (strcmp (name, BFD_IND_SECTION_NAME) == 0)
1097 newsect = bfd_ind_section_ptr;
1100 struct section_hash_entry *sh;
1102 sh = section_hash_lookup (&abfd->section_htab, name, TRUE, FALSE);
1106 newsect = &sh->section;
1107 if (newsect->name != NULL)
1109 /* Section already exists. */
1113 newsect->name = name;
1114 return bfd_section_init (abfd, newsect);
1117 /* Call new_section_hook when "creating" the standard abs, com, und
1118 and ind sections to tack on format specific section data.
1119 Also, create a proper section symbol. */
1120 if (! BFD_SEND (abfd, _new_section_hook, (abfd, newsect)))
1127 bfd_make_section_anyway_with_flags
1130 asection *bfd_make_section_anyway_with_flags
1131 (bfd *abfd, const char *name, flagword flags);
1134 Create a new empty section called @var{name} and attach it to the end of
1135 the chain of sections for @var{abfd}. Create a new section even if there
1136 is already a section with that name. Also set the attributes of the
1137 new section to the value @var{flags}.
1139 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
1140 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
1141 o <<bfd_error_no_memory>> - If memory allocation fails.
1145 bfd_make_section_anyway_with_flags (bfd *abfd, const char *name,
1148 struct section_hash_entry *sh;
1151 if (abfd->output_has_begun)
1153 bfd_set_error (bfd_error_invalid_operation);
1157 sh = section_hash_lookup (&abfd->section_htab, name, TRUE, FALSE);
1161 newsect = &sh->section;
1162 if (newsect->name != NULL)
1164 /* We are making a section of the same name. Put it in the
1165 section hash table. Even though we can't find it directly by a
1166 hash lookup, we'll be able to find the section by traversing
1167 sh->root.next quicker than looking at all the bfd sections. */
1168 struct section_hash_entry *new_sh;
1169 new_sh = (struct section_hash_entry *)
1170 bfd_section_hash_newfunc (NULL, &abfd->section_htab, name);
1174 new_sh->root = sh->root;
1175 sh->root.next = &new_sh->root;
1176 newsect = &new_sh->section;
1179 newsect->flags = flags;
1180 newsect->name = name;
1181 return bfd_section_init (abfd, newsect);
1186 bfd_make_section_anyway
1189 asection *bfd_make_section_anyway (bfd *abfd, const char *name);
1192 Create a new empty section called @var{name} and attach it to the end of
1193 the chain of sections for @var{abfd}. Create a new section even if there
1194 is already a section with that name.
1196 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
1197 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
1198 o <<bfd_error_no_memory>> - If memory allocation fails.
1202 bfd_make_section_anyway (bfd *abfd, const char *name)
1204 return bfd_make_section_anyway_with_flags (abfd, name, 0);
1209 bfd_make_section_with_flags
1212 asection *bfd_make_section_with_flags
1213 (bfd *, const char *name, flagword flags);
1216 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
1217 bfd_set_error ()) without changing the section chain if there is already a
1218 section named @var{name}. Also set the attributes of the new section to
1219 the value @var{flags}. If there is an error, return <<NULL>> and set
1224 bfd_make_section_with_flags (bfd *abfd, const char *name,
1227 struct section_hash_entry *sh;
1230 if (abfd->output_has_begun)
1232 bfd_set_error (bfd_error_invalid_operation);
1236 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0
1237 || strcmp (name, BFD_COM_SECTION_NAME) == 0
1238 || strcmp (name, BFD_UND_SECTION_NAME) == 0
1239 || strcmp (name, BFD_IND_SECTION_NAME) == 0)
1242 sh = section_hash_lookup (&abfd->section_htab, name, TRUE, FALSE);
1246 newsect = &sh->section;
1247 if (newsect->name != NULL)
1249 /* Section already exists. */
1253 newsect->name = name;
1254 newsect->flags = flags;
1255 return bfd_section_init (abfd, newsect);
1263 asection *bfd_make_section (bfd *, const char *name);
1266 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
1267 bfd_set_error ()) without changing the section chain if there is already a
1268 section named @var{name}. If there is an error, return <<NULL>> and set
1273 bfd_make_section (bfd *abfd, const char *name)
1275 return bfd_make_section_with_flags (abfd, name, 0);
1280 bfd_set_section_flags
1283 bfd_boolean bfd_set_section_flags
1284 (bfd *abfd, asection *sec, flagword flags);
1287 Set the attributes of the section @var{sec} in the BFD
1288 @var{abfd} to the value @var{flags}. Return <<TRUE>> on success,
1289 <<FALSE>> on error. Possible error returns are:
1291 o <<bfd_error_invalid_operation>> -
1292 The section cannot have one or more of the attributes
1293 requested. For example, a .bss section in <<a.out>> may not
1294 have the <<SEC_HAS_CONTENTS>> field set.
1299 bfd_set_section_flags (bfd *abfd ATTRIBUTE_UNUSED,
1303 section->flags = flags;
1312 void bfd_rename_section
1313 (bfd *abfd, asection *sec, const char *newname);
1316 Rename section @var{sec} in @var{abfd} to @var{newname}.
1320 bfd_rename_section (bfd *abfd, sec_ptr sec, const char *newname)
1322 struct section_hash_entry *sh;
1324 sh = (struct section_hash_entry *)
1325 ((char *) sec - offsetof (struct section_hash_entry, section));
1326 sh->section.name = newname;
1327 bfd_hash_rename (&abfd->section_htab, newname, &sh->root);
1332 bfd_map_over_sections
1335 void bfd_map_over_sections
1337 void (*func) (bfd *abfd, asection *sect, void *obj),
1341 Call the provided function @var{func} for each section
1342 attached to the BFD @var{abfd}, passing @var{obj} as an
1343 argument. The function will be called as if by
1345 | func (abfd, the_section, obj);
1347 This is the preferred method for iterating over sections; an
1348 alternative would be to use a loop:
1351 | for (p = abfd->sections; p != NULL; p = p->next)
1352 | func (abfd, p, ...)
1357 bfd_map_over_sections (bfd *abfd,
1358 void (*operation) (bfd *, asection *, void *),
1364 for (sect = abfd->sections; sect != NULL; i++, sect = sect->next)
1365 (*operation) (abfd, sect, user_storage);
1367 if (i != abfd->section_count) /* Debugging */
1373 bfd_sections_find_if
1376 asection *bfd_sections_find_if
1378 bfd_boolean (*operation) (bfd *abfd, asection *sect, void *obj),
1382 Call the provided function @var{operation} for each section
1383 attached to the BFD @var{abfd}, passing @var{obj} as an
1384 argument. The function will be called as if by
1386 | operation (abfd, the_section, obj);
1388 It returns the first section for which @var{operation} returns true.
1393 bfd_sections_find_if (bfd *abfd,
1394 bfd_boolean (*operation) (bfd *, asection *, void *),
1399 for (sect = abfd->sections; sect != NULL; sect = sect->next)
1400 if ((*operation) (abfd, sect, user_storage))
1408 bfd_set_section_size
1411 bfd_boolean bfd_set_section_size
1412 (bfd *abfd, asection *sec, bfd_size_type val);
1415 Set @var{sec} to the size @var{val}. If the operation is
1416 ok, then <<TRUE>> is returned, else <<FALSE>>.
1418 Possible error returns:
1419 o <<bfd_error_invalid_operation>> -
1420 Writing has started to the BFD, so setting the size is invalid.
1425 bfd_set_section_size (bfd *abfd, sec_ptr ptr, bfd_size_type val)
1427 /* Once you've started writing to any section you cannot create or change
1428 the size of any others. */
1430 if (abfd->output_has_begun)
1432 bfd_set_error (bfd_error_invalid_operation);
1442 bfd_set_section_contents
1445 bfd_boolean bfd_set_section_contents
1446 (bfd *abfd, asection *section, const void *data,
1447 file_ptr offset, bfd_size_type count);
1450 Sets the contents of the section @var{section} in BFD
1451 @var{abfd} to the data starting in memory at @var{data}. The
1452 data is written to the output section starting at offset
1453 @var{offset} for @var{count} octets.
1455 Normally <<TRUE>> is returned, else <<FALSE>>. Possible error
1457 o <<bfd_error_no_contents>> -
1458 The output section does not have the <<SEC_HAS_CONTENTS>>
1459 attribute, so nothing can be written to it.
1462 This routine is front end to the back end function
1463 <<_bfd_set_section_contents>>.
1468 bfd_set_section_contents (bfd *abfd,
1470 const void *location,
1472 bfd_size_type count)
1476 if (!(bfd_get_section_flags (abfd, section) & SEC_HAS_CONTENTS))
1478 bfd_set_error (bfd_error_no_contents);
1483 if ((bfd_size_type) offset > sz
1485 || offset + count > sz
1486 || count != (size_t) count)
1488 bfd_set_error (bfd_error_bad_value);
1492 if (!bfd_write_p (abfd))
1494 bfd_set_error (bfd_error_invalid_operation);
1498 /* Record a copy of the data in memory if desired. */
1499 if (section->contents
1500 && location != section->contents + offset)
1501 memcpy (section->contents + offset, location, (size_t) count);
1503 if (BFD_SEND (abfd, _bfd_set_section_contents,
1504 (abfd, section, location, offset, count)))
1506 abfd->output_has_begun = TRUE;
1515 bfd_get_section_contents
1518 bfd_boolean bfd_get_section_contents
1519 (bfd *abfd, asection *section, void *location, file_ptr offset,
1520 bfd_size_type count);
1523 Read data from @var{section} in BFD @var{abfd}
1524 into memory starting at @var{location}. The data is read at an
1525 offset of @var{offset} from the start of the input section,
1526 and is read for @var{count} bytes.
1528 If the contents of a constructor with the <<SEC_CONSTRUCTOR>>
1529 flag set are requested or if the section does not have the
1530 <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled
1531 with zeroes. If no errors occur, <<TRUE>> is returned, else
1536 bfd_get_section_contents (bfd *abfd,
1540 bfd_size_type count)
1544 if (section->flags & SEC_CONSTRUCTOR)
1546 memset (location, 0, (size_t) count);
1550 if (abfd->direction != write_direction && section->rawsize != 0)
1551 sz = section->rawsize;
1554 if ((bfd_size_type) offset > sz
1556 || offset + count > sz
1557 || count != (size_t) count)
1559 bfd_set_error (bfd_error_bad_value);
1567 if ((section->flags & SEC_HAS_CONTENTS) == 0)
1569 memset (location, 0, (size_t) count);
1573 if ((section->flags & SEC_IN_MEMORY) != 0)
1575 if (section->contents == NULL)
1577 /* This can happen because of errors earlier on in the linking process.
1578 We do not want to seg-fault here, so clear the flag and return an
1580 section->flags &= ~ SEC_IN_MEMORY;
1581 bfd_set_error (bfd_error_invalid_operation);
1585 memmove (location, section->contents + offset, (size_t) count);
1589 return BFD_SEND (abfd, _bfd_get_section_contents,
1590 (abfd, section, location, offset, count));
1595 bfd_malloc_and_get_section
1598 bfd_boolean bfd_malloc_and_get_section
1599 (bfd *abfd, asection *section, bfd_byte **buf);
1602 Read all data from @var{section} in BFD @var{abfd}
1603 into a buffer, *@var{buf}, malloc'd by this function.
1607 bfd_malloc_and_get_section (bfd *abfd, sec_ptr sec, bfd_byte **buf)
1610 return bfd_get_full_section_contents (abfd, sec, buf);
1614 bfd_copy_private_section_data
1617 bfd_boolean bfd_copy_private_section_data
1618 (bfd *ibfd, asection *isec, bfd *obfd, asection *osec);
1621 Copy private section information from @var{isec} in the BFD
1622 @var{ibfd} to the section @var{osec} in the BFD @var{obfd}.
1623 Return <<TRUE>> on success, <<FALSE>> on error. Possible error
1626 o <<bfd_error_no_memory>> -
1627 Not enough memory exists to create private data for @var{osec}.
1629 .#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \
1630 . BFD_SEND (obfd, _bfd_copy_private_section_data, \
1631 . (ibfd, isection, obfd, osection))
1636 bfd_generic_is_group_section
1639 bfd_boolean bfd_generic_is_group_section (bfd *, const asection *sec);
1642 Returns TRUE if @var{sec} is a member of a group.
1646 bfd_generic_is_group_section (bfd *abfd ATTRIBUTE_UNUSED,
1647 const asection *sec ATTRIBUTE_UNUSED)
1654 bfd_generic_discard_group
1657 bfd_boolean bfd_generic_discard_group (bfd *abfd, asection *group);
1660 Remove all members of @var{group} from the output.
1664 bfd_generic_discard_group (bfd *abfd ATTRIBUTE_UNUSED,
1665 asection *group ATTRIBUTE_UNUSED)