1 /* Object file "section" support for the BFD library.
2 Copyright (C) 1990-2018 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 contains common symbols (symbols may be defined
225 . multiple times, the value of a symbol is the amount of
226 . space it requires, and the largest symbol value is the one
227 . used). Most targets have exactly one of these (which we
228 . translate to bfd_com_section_ptr), but ECOFF has two. *}
229 .#define SEC_IS_COMMON 0x1000
231 . {* The section contains only debugging information. For
232 . example, this is set for ELF .debug and .stab sections.
233 . strip tests this flag to see if a section can be
235 .#define SEC_DEBUGGING 0x2000
237 . {* The contents of this section are held in memory pointed to
238 . by the contents field. This is checked by bfd_get_section_contents,
239 . and the data is retrieved from memory if appropriate. *}
240 .#define SEC_IN_MEMORY 0x4000
242 . {* The contents of this section are to be excluded by the
243 . linker for executable and shared objects unless those
244 . objects are to be further relocated. *}
245 .#define SEC_EXCLUDE 0x8000
247 . {* The contents of this section are to be sorted based on the sum of
248 . the symbol and addend values specified by the associated relocation
249 . entries. Entries without associated relocation entries will be
250 . appended to the end of the section in an unspecified order. *}
251 .#define SEC_SORT_ENTRIES 0x10000
253 . {* When linking, duplicate sections of the same name should be
254 . discarded, rather than being combined into a single section as
255 . is usually done. This is similar to how common symbols are
256 . handled. See SEC_LINK_DUPLICATES below. *}
257 .#define SEC_LINK_ONCE 0x20000
259 . {* If SEC_LINK_ONCE is set, this bitfield describes how the linker
260 . should handle duplicate sections. *}
261 .#define SEC_LINK_DUPLICATES 0xc0000
263 . {* This value for SEC_LINK_DUPLICATES means that duplicate
264 . sections with the same name should simply be discarded. *}
265 .#define SEC_LINK_DUPLICATES_DISCARD 0x0
267 . {* This value for SEC_LINK_DUPLICATES means that the linker
268 . should warn if there are any duplicate sections, although
269 . it should still only link one copy. *}
270 .#define SEC_LINK_DUPLICATES_ONE_ONLY 0x40000
272 . {* This value for SEC_LINK_DUPLICATES means that the linker
273 . should warn if any duplicate sections are a different size. *}
274 .#define SEC_LINK_DUPLICATES_SAME_SIZE 0x80000
276 . {* This value for SEC_LINK_DUPLICATES means that the linker
277 . should warn if any duplicate sections contain different
279 .#define SEC_LINK_DUPLICATES_SAME_CONTENTS \
280 . (SEC_LINK_DUPLICATES_ONE_ONLY | SEC_LINK_DUPLICATES_SAME_SIZE)
282 . {* This section was created by the linker as part of dynamic
283 . relocation or other arcane processing. It is skipped when
284 . going through the first-pass output, trusting that someone
285 . else up the line will take care of it later. *}
286 .#define SEC_LINKER_CREATED 0x100000
288 . {* This section should not be subject to garbage collection.
289 . Also set to inform the linker that this section should not be
290 . listed in the link map as discarded. *}
291 .#define SEC_KEEP 0x200000
293 . {* This section contains "short" data, and should be placed
295 .#define SEC_SMALL_DATA 0x400000
297 . {* Attempt to merge identical entities in the section.
298 . Entity size is given in the entsize field. *}
299 .#define SEC_MERGE 0x800000
301 . {* If given with SEC_MERGE, entities to merge are zero terminated
302 . strings where entsize specifies character size instead of fixed
304 .#define SEC_STRINGS 0x1000000
306 . {* This section contains data about section groups. *}
307 .#define SEC_GROUP 0x2000000
309 . {* The section is a COFF shared library section. This flag is
310 . only for the linker. If this type of section appears in
311 . the input file, the linker must copy it to the output file
312 . without changing the vma or size. FIXME: Although this
313 . was originally intended to be general, it really is COFF
314 . specific (and the flag was renamed to indicate this). It
315 . might be cleaner to have some more general mechanism to
316 . allow the back end to control what the linker does with
318 .#define SEC_COFF_SHARED_LIBRARY 0x4000000
320 . {* This input section should be copied to output in reverse order
321 . as an array of pointers. This is for ELF linker internal use
323 .#define SEC_ELF_REVERSE_COPY 0x4000000
325 . {* This section contains data which may be shared with other
326 . executables or shared objects. This is for COFF only. *}
327 .#define SEC_COFF_SHARED 0x8000000
329 . {* This section should be compressed. This is for ELF linker
330 . internal use only. *}
331 .#define SEC_ELF_COMPRESS 0x8000000
333 . {* When a section with this flag is being linked, then if the size of
334 . the input section is less than a page, it should not cross a page
335 . boundary. If the size of the input section is one page or more,
336 . it should be aligned on a page boundary. This is for TI
337 . TMS320C54X only. *}
338 .#define SEC_TIC54X_BLOCK 0x10000000
340 . {* This section should be renamed. This is for ELF linker
341 . internal use only. *}
342 .#define SEC_ELF_RENAME 0x10000000
344 . {* Conditionally link this section; do not link if there are no
345 . references found to any symbol in the section. This is for TI
346 . TMS320C54X only. *}
347 .#define SEC_TIC54X_CLINK 0x20000000
349 . {* This section contains vliw code. This is for Toshiba MeP only. *}
350 .#define SEC_MEP_VLIW 0x20000000
352 . {* Indicate that section has the no read flag set. This happens
353 . when memory read flag isn't set. *}
354 .#define SEC_COFF_NOREAD 0x40000000
356 . {* Indicate that section has the purecode flag set. *}
357 .#define SEC_ELF_PURECODE 0x80000000
359 . {* End of section flags. *}
361 . {* Some internal packed boolean fields. *}
363 . {* See the vma field. *}
364 . unsigned int user_set_vma : 1;
366 . {* A mark flag used by some of the linker backends. *}
367 . unsigned int linker_mark : 1;
369 . {* Another mark flag used by some of the linker backends. Set for
370 . output sections that have an input section. *}
371 . unsigned int linker_has_input : 1;
373 . {* Mark flag used by some linker backends for garbage collection. *}
374 . unsigned int gc_mark : 1;
376 . {* Section compression status. *}
377 . unsigned int compress_status : 2;
378 .#define COMPRESS_SECTION_NONE 0
379 .#define COMPRESS_SECTION_DONE 1
380 .#define DECOMPRESS_SECTION_SIZED 2
382 . {* The following flags are used by the ELF linker. *}
384 . {* Mark sections which have been allocated to segments. *}
385 . unsigned int segment_mark : 1;
387 . {* Type of sec_info information. *}
388 . unsigned int sec_info_type:3;
389 .#define SEC_INFO_TYPE_NONE 0
390 .#define SEC_INFO_TYPE_STABS 1
391 .#define SEC_INFO_TYPE_MERGE 2
392 .#define SEC_INFO_TYPE_EH_FRAME 3
393 .#define SEC_INFO_TYPE_JUST_SYMS 4
394 .#define SEC_INFO_TYPE_TARGET 5
395 .#define SEC_INFO_TYPE_EH_FRAME_ENTRY 6
397 . {* Nonzero if this section uses RELA relocations, rather than REL. *}
398 . unsigned int use_rela_p:1;
400 . {* Bits used by various backends. The generic code doesn't touch
403 . unsigned int sec_flg0:1;
404 . unsigned int sec_flg1:1;
405 . unsigned int sec_flg2:1;
406 . unsigned int sec_flg3:1;
407 . unsigned int sec_flg4:1;
408 . unsigned int sec_flg5:1;
410 . {* End of internal packed boolean fields. *}
412 . {* The virtual memory address of the section - where it will be
413 . at run time. The symbols are relocated against this. The
414 . user_set_vma flag is maintained by bfd; if it's not set, the
415 . backend can assign addresses (for example, in <<a.out>>, where
416 . the default address for <<.data>> is dependent on the specific
417 . target and various flags). *}
420 . {* The load address of the section - where it would be in a
421 . rom image; really only used for writing section header
425 . {* The size of the section in *octets*, as it will be output.
426 . Contains a value even if the section has no contents (e.g., the
427 . size of <<.bss>>). *}
428 . bfd_size_type size;
430 . {* For input sections, the original size on disk of the section, in
431 . octets. This field should be set for any section whose size is
432 . changed by linker relaxation. It is required for sections where
433 . the linker relaxation scheme doesn't cache altered section and
434 . reloc contents (stabs, eh_frame, SEC_MERGE, some coff relaxing
435 . targets), and thus the original size needs to be kept to read the
436 . section multiple times. For output sections, rawsize holds the
437 . section size calculated on a previous linker relaxation pass. *}
438 . bfd_size_type rawsize;
440 . {* The compressed size of the section in octets. *}
441 . bfd_size_type compressed_size;
443 . {* Relaxation table. *}
444 . struct relax_table *relax;
446 . {* Count of used relaxation table entries. *}
450 . {* If this section is going to be output, then this value is the
451 . offset in *bytes* into the output section of the first byte in the
452 . input section (byte ==> smallest addressable unit on the
453 . target). In most cases, if this was going to start at the
454 . 100th octet (8-bit quantity) in the output section, this value
455 . would be 100. However, if the target byte size is 16 bits
456 . (bfd_octets_per_byte is "2"), this value would be 50. *}
457 . bfd_vma output_offset;
459 . {* The output section through which to map on output. *}
460 . struct bfd_section *output_section;
462 . {* The alignment requirement of the section, as an exponent of 2 -
463 . e.g., 3 aligns to 2^3 (or 8). *}
464 . unsigned int alignment_power;
466 . {* If an input section, a pointer to a vector of relocation
467 . records for the data in this section. *}
468 . struct reloc_cache_entry *relocation;
470 . {* If an output section, a pointer to a vector of pointers to
471 . relocation records for the data in this section. *}
472 . struct reloc_cache_entry **orelocation;
474 . {* The number of relocation records in one of the above. *}
475 . unsigned reloc_count;
477 . {* Information below is back end specific - and not always used
480 . {* File position of section data. *}
483 . {* File position of relocation info. *}
484 . file_ptr rel_filepos;
486 . {* File position of line data. *}
487 . file_ptr line_filepos;
489 . {* Pointer to data for applications. *}
492 . {* If the SEC_IN_MEMORY flag is set, this points to the actual
494 . unsigned char *contents;
496 . {* Attached line number information. *}
499 . {* Number of line number records. *}
500 . unsigned int lineno_count;
502 . {* Entity size for merging purposes. *}
503 . unsigned int entsize;
505 . {* Points to the kept section if this section is a link-once section,
506 . and is discarded. *}
507 . struct bfd_section *kept_section;
509 . {* When a section is being output, this value changes as more
510 . linenumbers are written out. *}
511 . file_ptr moving_line_filepos;
513 . {* What the section number is in the target world. *}
518 . {* If this is a constructor section then here is a list of the
519 . relocations created to relocate items within it. *}
520 . struct relent_chain *constructor_chain;
522 . {* The BFD which owns the section. *}
525 . {* A symbol which points at this section only. *}
526 . struct bfd_symbol *symbol;
527 . struct bfd_symbol **symbol_ptr_ptr;
529 . {* Early in the link process, map_head and map_tail are used to build
530 . a list of input sections attached to an output section. Later,
531 . output sections use these fields for a list of bfd_link_order
534 . struct bfd_link_order *link_order;
535 . struct bfd_section *s;
536 . } map_head, map_tail;
539 .{* Relax table contains information about instructions which can
540 . be removed by relaxation -- replacing a long address with a
542 .struct relax_table {
543 . {* Address where bytes may be deleted. *}
546 . {* Number of bytes to be deleted. *}
550 .{* Note: the following are provided as inline functions rather than macros
551 . because not all callers use the return value. A macro implementation
552 . would use a comma expression, eg: "((ptr)->foo = val, TRUE)" and some
553 . compilers will complain about comma expressions that have no effect. *}
554 .static inline bfd_boolean
555 .bfd_set_section_userdata (bfd * abfd ATTRIBUTE_UNUSED, asection * ptr,
558 . ptr->userdata = val;
562 .static inline bfd_boolean
563 .bfd_set_section_vma (bfd * abfd ATTRIBUTE_UNUSED, asection * ptr, bfd_vma val)
565 . ptr->vma = ptr->lma = val;
566 . ptr->user_set_vma = TRUE;
570 .static inline bfd_boolean
571 .bfd_set_section_alignment (bfd * abfd ATTRIBUTE_UNUSED, asection * ptr,
574 . ptr->alignment_power = val;
578 .{* These sections are global, and are managed by BFD. The application
579 . and target back end are not permitted to change the values in
581 .extern asection _bfd_std_section[4];
583 .#define BFD_ABS_SECTION_NAME "*ABS*"
584 .#define BFD_UND_SECTION_NAME "*UND*"
585 .#define BFD_COM_SECTION_NAME "*COM*"
586 .#define BFD_IND_SECTION_NAME "*IND*"
588 .{* Pointer to the common section. *}
589 .#define bfd_com_section_ptr (&_bfd_std_section[0])
590 .{* Pointer to the undefined section. *}
591 .#define bfd_und_section_ptr (&_bfd_std_section[1])
592 .{* Pointer to the absolute section. *}
593 .#define bfd_abs_section_ptr (&_bfd_std_section[2])
594 .{* Pointer to the indirect section. *}
595 .#define bfd_ind_section_ptr (&_bfd_std_section[3])
597 .#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr)
598 .#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr)
599 .#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr)
601 .#define bfd_is_const_section(SEC) \
602 . ( ((SEC) == bfd_abs_section_ptr) \
603 . || ((SEC) == bfd_und_section_ptr) \
604 . || ((SEC) == bfd_com_section_ptr) \
605 . || ((SEC) == bfd_ind_section_ptr))
607 .{* Macros to handle insertion and deletion of a bfd's sections. These
608 . only handle the list pointers, ie. do not adjust section_count,
609 . target_index etc. *}
610 .#define bfd_section_list_remove(ABFD, S) \
613 . asection *_s = S; \
614 . asection *_next = _s->next; \
615 . asection *_prev = _s->prev; \
617 . _prev->next = _next; \
619 . (ABFD)->sections = _next; \
621 . _next->prev = _prev; \
623 . (ABFD)->section_last = _prev; \
626 .#define bfd_section_list_append(ABFD, S) \
629 . asection *_s = S; \
630 . bfd *_abfd = ABFD; \
632 . if (_abfd->section_last) \
634 . _s->prev = _abfd->section_last; \
635 . _abfd->section_last->next = _s; \
640 . _abfd->sections = _s; \
642 . _abfd->section_last = _s; \
645 .#define bfd_section_list_prepend(ABFD, S) \
648 . asection *_s = S; \
649 . bfd *_abfd = ABFD; \
651 . if (_abfd->sections) \
653 . _s->next = _abfd->sections; \
654 . _abfd->sections->prev = _s; \
659 . _abfd->section_last = _s; \
661 . _abfd->sections = _s; \
664 .#define bfd_section_list_insert_after(ABFD, A, S) \
667 . asection *_a = A; \
668 . asection *_s = S; \
669 . asection *_next = _a->next; \
670 . _s->next = _next; \
674 . _next->prev = _s; \
676 . (ABFD)->section_last = _s; \
679 .#define bfd_section_list_insert_before(ABFD, B, S) \
682 . asection *_b = B; \
683 . asection *_s = S; \
684 . asection *_prev = _b->prev; \
685 . _s->prev = _prev; \
689 . _prev->next = _s; \
691 . (ABFD)->sections = _s; \
694 .#define bfd_section_removed_from_list(ABFD, S) \
695 . ((S)->next == NULL ? (ABFD)->section_last != (S) : (S)->next->prev != (S))
697 .#define BFD_FAKE_SECTION(SEC, SYM, NAME, IDX, FLAGS) \
698 . {* name, id, index, next, prev, flags, user_set_vma, *} \
699 . { NAME, IDX, 0, NULL, NULL, FLAGS, 0, \
701 . {* linker_mark, linker_has_input, gc_mark, decompress_status, *} \
704 . {* segment_mark, sec_info_type, use_rela_p, *} \
707 . {* sec_flg0, sec_flg1, sec_flg2, sec_flg3, sec_flg4, sec_flg5, *} \
708 . 0, 0, 0, 0, 0, 0, \
710 . {* vma, lma, size, rawsize, compressed_size, relax, relax_count, *} \
711 . 0, 0, 0, 0, 0, 0, 0, \
713 . {* output_offset, output_section, alignment_power, *} \
716 . {* relocation, orelocation, reloc_count, filepos, rel_filepos, *} \
717 . NULL, NULL, 0, 0, 0, \
719 . {* line_filepos, userdata, contents, lineno, lineno_count, *} \
720 . 0, NULL, NULL, NULL, 0, \
722 . {* entsize, kept_section, moving_line_filepos, *} \
725 . {* target_index, used_by_bfd, constructor_chain, owner, *} \
726 . 0, NULL, NULL, NULL, \
728 . {* symbol, symbol_ptr_ptr, *} \
729 . (struct bfd_symbol *) SYM, &SEC.symbol, \
731 . {* map_head, map_tail *} \
732 . { NULL }, { NULL } \
735 .{* We use a macro to initialize the static asymbol structures because
736 . traditional C does not permit us to initialize a union member while
737 . gcc warns if we don't initialize it.
738 . the_bfd, name, value, attr, section [, udata] *}
740 .#define GLOBAL_SYM_INIT(NAME, SECTION) \
741 . { 0, NAME, 0, BSF_SECTION_SYM, SECTION, { 0 }}
743 .#define GLOBAL_SYM_INIT(NAME, SECTION) \
744 . { 0, NAME, 0, BSF_SECTION_SYM, SECTION }
749 /* These symbols are global, not specific to any BFD. Therefore, anything
750 that tries to change them is broken, and should be repaired. */
752 static const asymbol global_syms[] =
754 GLOBAL_SYM_INIT (BFD_COM_SECTION_NAME, bfd_com_section_ptr),
755 GLOBAL_SYM_INIT (BFD_UND_SECTION_NAME, bfd_und_section_ptr),
756 GLOBAL_SYM_INIT (BFD_ABS_SECTION_NAME, bfd_abs_section_ptr),
757 GLOBAL_SYM_INIT (BFD_IND_SECTION_NAME, bfd_ind_section_ptr)
760 #define STD_SECTION(NAME, IDX, FLAGS) \
761 BFD_FAKE_SECTION(_bfd_std_section[IDX], &global_syms[IDX], NAME, IDX, FLAGS)
763 asection _bfd_std_section[] = {
764 STD_SECTION (BFD_COM_SECTION_NAME, 0, SEC_IS_COMMON),
765 STD_SECTION (BFD_UND_SECTION_NAME, 1, 0),
766 STD_SECTION (BFD_ABS_SECTION_NAME, 2, 0),
767 STD_SECTION (BFD_IND_SECTION_NAME, 3, 0)
771 /* Initialize an entry in the section hash table. */
773 struct bfd_hash_entry *
774 bfd_section_hash_newfunc (struct bfd_hash_entry *entry,
775 struct bfd_hash_table *table,
778 /* Allocate the structure if it has not already been allocated by a
782 entry = (struct bfd_hash_entry *)
783 bfd_hash_allocate (table, sizeof (struct section_hash_entry));
788 /* Call the allocation method of the superclass. */
789 entry = bfd_hash_newfunc (entry, table, string);
791 memset (&((struct section_hash_entry *) entry)->section, 0,
797 #define section_hash_lookup(table, string, create, copy) \
798 ((struct section_hash_entry *) \
799 bfd_hash_lookup ((table), (string), (create), (copy)))
801 /* Create a symbol whose only job is to point to this section. This
802 is useful for things like relocs which are relative to the base
806 _bfd_generic_new_section_hook (bfd *abfd, asection *newsect)
808 newsect->symbol = bfd_make_empty_symbol (abfd);
809 if (newsect->symbol == NULL)
812 newsect->symbol->name = newsect->name;
813 newsect->symbol->value = 0;
814 newsect->symbol->section = newsect;
815 newsect->symbol->flags = BSF_SECTION_SYM;
817 newsect->symbol_ptr_ptr = &newsect->symbol;
821 static unsigned int section_id = 0x10; /* id 0 to 3 used by STD_SECTION. */
823 /* Initializes a new section. NEWSECT->NAME is already set. */
826 bfd_section_init (bfd *abfd, asection *newsect)
828 newsect->id = section_id;
829 newsect->index = abfd->section_count;
830 newsect->owner = abfd;
832 if (! BFD_SEND (abfd, _new_section_hook, (abfd, newsect)))
836 abfd->section_count++;
837 bfd_section_list_append (abfd, newsect);
844 section prototypes, , typedef asection, Sections
848 These are the functions exported by the section handling part of BFD.
853 bfd_section_list_clear
856 void bfd_section_list_clear (bfd *);
859 Clears the section list, and also resets the section count and
864 bfd_section_list_clear (bfd *abfd)
866 abfd->sections = NULL;
867 abfd->section_last = NULL;
868 abfd->section_count = 0;
869 memset (abfd->section_htab.table, 0,
870 abfd->section_htab.size * sizeof (struct bfd_hash_entry *));
871 abfd->section_htab.count = 0;
876 bfd_get_section_by_name
879 asection *bfd_get_section_by_name (bfd *abfd, const char *name);
882 Return the most recently created section attached to @var{abfd}
883 named @var{name}. Return NULL if no such section exists.
887 bfd_get_section_by_name (bfd *abfd, const char *name)
889 struct section_hash_entry *sh;
891 sh = section_hash_lookup (&abfd->section_htab, name, FALSE, FALSE);
900 bfd_get_next_section_by_name
903 asection *bfd_get_next_section_by_name (bfd *ibfd, asection *sec);
906 Given @var{sec} is a section returned by @code{bfd_get_section_by_name},
907 return the next most recently created section attached to the same
908 BFD with the same name, or if no such section exists in the same BFD and
909 IBFD is non-NULL, the next section with the same name in any input
910 BFD following IBFD. Return NULL on finding no section.
914 bfd_get_next_section_by_name (bfd *ibfd, 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)
934 while ((ibfd = ibfd->link.next) != NULL)
936 asection *s = bfd_get_section_by_name (ibfd, name);
947 bfd_get_linker_section
950 asection *bfd_get_linker_section (bfd *abfd, const char *name);
953 Return the linker created section attached to @var{abfd}
954 named @var{name}. Return NULL if no such section exists.
958 bfd_get_linker_section (bfd *abfd, const char *name)
960 asection *sec = bfd_get_section_by_name (abfd, name);
962 while (sec != NULL && (sec->flags & SEC_LINKER_CREATED) == 0)
963 sec = bfd_get_next_section_by_name (NULL, sec);
969 bfd_get_section_by_name_if
972 asection *bfd_get_section_by_name_if
975 bfd_boolean (*func) (bfd *abfd, asection *sect, void *obj),
979 Call the provided function @var{func} for each section
980 attached to the BFD @var{abfd} whose name matches @var{name},
981 passing @var{obj} as an argument. The function will be called
984 | func (abfd, the_section, obj);
986 It returns the first section for which @var{func} returns true,
992 bfd_get_section_by_name_if (bfd *abfd, const char *name,
993 bfd_boolean (*operation) (bfd *,
998 struct section_hash_entry *sh;
1001 sh = section_hash_lookup (&abfd->section_htab, name, FALSE, FALSE);
1005 hash = sh->root.hash;
1006 for (; sh != NULL; sh = (struct section_hash_entry *) sh->root.next)
1007 if (sh->root.hash == hash
1008 && strcmp (sh->root.string, name) == 0
1009 && (*operation) (abfd, &sh->section, user_storage))
1010 return &sh->section;
1017 bfd_get_unique_section_name
1020 char *bfd_get_unique_section_name
1021 (bfd *abfd, const char *templat, int *count);
1024 Invent a section name that is unique in @var{abfd} by tacking
1025 a dot and a digit suffix onto the original @var{templat}. If
1026 @var{count} is non-NULL, then it specifies the first number
1027 tried as a suffix to generate a unique name. The value
1028 pointed to by @var{count} will be incremented in this case.
1032 bfd_get_unique_section_name (bfd *abfd, const char *templat, int *count)
1038 len = strlen (templat);
1039 sname = (char *) bfd_malloc (len + 8);
1042 memcpy (sname, templat, len);
1049 /* If we have a million sections, something is badly wrong. */
1052 sprintf (sname + len, ".%d", num++);
1054 while (section_hash_lookup (&abfd->section_htab, sname, FALSE, FALSE));
1063 bfd_make_section_old_way
1066 asection *bfd_make_section_old_way (bfd *abfd, const char *name);
1069 Create a new empty section called @var{name}
1070 and attach it to the end of the chain of sections for the
1071 BFD @var{abfd}. An attempt to create a section with a name which
1072 is already in use returns its pointer without changing the
1075 It has the funny name since this is the way it used to be
1076 before it was rewritten....
1078 Possible errors are:
1079 o <<bfd_error_invalid_operation>> -
1080 If output has already started for this BFD.
1081 o <<bfd_error_no_memory>> -
1082 If memory allocation fails.
1087 bfd_make_section_old_way (bfd *abfd, const char *name)
1091 if (abfd->output_has_begun)
1093 bfd_set_error (bfd_error_invalid_operation);
1097 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0)
1098 newsect = bfd_abs_section_ptr;
1099 else if (strcmp (name, BFD_COM_SECTION_NAME) == 0)
1100 newsect = bfd_com_section_ptr;
1101 else if (strcmp (name, BFD_UND_SECTION_NAME) == 0)
1102 newsect = bfd_und_section_ptr;
1103 else if (strcmp (name, BFD_IND_SECTION_NAME) == 0)
1104 newsect = bfd_ind_section_ptr;
1107 struct section_hash_entry *sh;
1109 sh = section_hash_lookup (&abfd->section_htab, name, TRUE, FALSE);
1113 newsect = &sh->section;
1114 if (newsect->name != NULL)
1116 /* Section already exists. */
1120 newsect->name = name;
1121 return bfd_section_init (abfd, newsect);
1124 /* Call new_section_hook when "creating" the standard abs, com, und
1125 and ind sections to tack on format specific section data.
1126 Also, create a proper section symbol. */
1127 if (! BFD_SEND (abfd, _new_section_hook, (abfd, newsect)))
1134 bfd_make_section_anyway_with_flags
1137 asection *bfd_make_section_anyway_with_flags
1138 (bfd *abfd, const char *name, flagword flags);
1141 Create a new empty section called @var{name} and attach it to the end of
1142 the chain of sections for @var{abfd}. Create a new section even if there
1143 is already a section with that name. Also set the attributes of the
1144 new section to the value @var{flags}.
1146 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
1147 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
1148 o <<bfd_error_no_memory>> - If memory allocation fails.
1152 bfd_make_section_anyway_with_flags (bfd *abfd, const char *name,
1155 struct section_hash_entry *sh;
1158 if (abfd->output_has_begun)
1160 bfd_set_error (bfd_error_invalid_operation);
1164 sh = section_hash_lookup (&abfd->section_htab, name, TRUE, FALSE);
1168 newsect = &sh->section;
1169 if (newsect->name != NULL)
1171 /* We are making a section of the same name. Put it in the
1172 section hash table. Even though we can't find it directly by a
1173 hash lookup, we'll be able to find the section by traversing
1174 sh->root.next quicker than looking at all the bfd sections. */
1175 struct section_hash_entry *new_sh;
1176 new_sh = (struct section_hash_entry *)
1177 bfd_section_hash_newfunc (NULL, &abfd->section_htab, name);
1181 new_sh->root = sh->root;
1182 sh->root.next = &new_sh->root;
1183 newsect = &new_sh->section;
1186 newsect->flags = flags;
1187 newsect->name = name;
1188 return bfd_section_init (abfd, newsect);
1193 bfd_make_section_anyway
1196 asection *bfd_make_section_anyway (bfd *abfd, const char *name);
1199 Create a new empty section called @var{name} and attach it to the end of
1200 the chain of sections for @var{abfd}. Create a new section even if there
1201 is already a section with that name.
1203 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
1204 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
1205 o <<bfd_error_no_memory>> - If memory allocation fails.
1209 bfd_make_section_anyway (bfd *abfd, const char *name)
1211 return bfd_make_section_anyway_with_flags (abfd, name, 0);
1216 bfd_make_section_with_flags
1219 asection *bfd_make_section_with_flags
1220 (bfd *, const char *name, flagword flags);
1223 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
1224 bfd_set_error ()) without changing the section chain if there is already a
1225 section named @var{name}. Also set the attributes of the new section to
1226 the value @var{flags}. If there is an error, return <<NULL>> and set
1231 bfd_make_section_with_flags (bfd *abfd, const char *name,
1234 struct section_hash_entry *sh;
1237 if (abfd == NULL || name == NULL || abfd->output_has_begun)
1239 bfd_set_error (bfd_error_invalid_operation);
1243 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0
1244 || strcmp (name, BFD_COM_SECTION_NAME) == 0
1245 || strcmp (name, BFD_UND_SECTION_NAME) == 0
1246 || strcmp (name, BFD_IND_SECTION_NAME) == 0)
1249 sh = section_hash_lookup (&abfd->section_htab, name, TRUE, FALSE);
1253 newsect = &sh->section;
1254 if (newsect->name != NULL)
1256 /* Section already exists. */
1260 newsect->name = name;
1261 newsect->flags = flags;
1262 return bfd_section_init (abfd, newsect);
1270 asection *bfd_make_section (bfd *, const char *name);
1273 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
1274 bfd_set_error ()) without changing the section chain if there is already a
1275 section named @var{name}. If there is an error, return <<NULL>> and set
1280 bfd_make_section (bfd *abfd, const char *name)
1282 return bfd_make_section_with_flags (abfd, name, 0);
1287 bfd_get_next_section_id
1290 int bfd_get_next_section_id (void);
1293 Returns the id that the next section created will have.
1297 bfd_get_next_section_id (void)
1304 bfd_set_section_flags
1307 bfd_boolean bfd_set_section_flags
1308 (bfd *abfd, asection *sec, flagword flags);
1311 Set the attributes of the section @var{sec} in the BFD
1312 @var{abfd} to the value @var{flags}. Return <<TRUE>> on success,
1313 <<FALSE>> on error. Possible error returns are:
1315 o <<bfd_error_invalid_operation>> -
1316 The section cannot have one or more of the attributes
1317 requested. For example, a .bss section in <<a.out>> may not
1318 have the <<SEC_HAS_CONTENTS>> field set.
1323 bfd_set_section_flags (bfd *abfd ATTRIBUTE_UNUSED,
1327 section->flags = flags;
1336 void bfd_rename_section
1337 (bfd *abfd, asection *sec, const char *newname);
1340 Rename section @var{sec} in @var{abfd} to @var{newname}.
1344 bfd_rename_section (bfd *abfd, sec_ptr sec, const char *newname)
1346 struct section_hash_entry *sh;
1348 sh = (struct section_hash_entry *)
1349 ((char *) sec - offsetof (struct section_hash_entry, section));
1350 sh->section.name = newname;
1351 bfd_hash_rename (&abfd->section_htab, newname, &sh->root);
1356 bfd_map_over_sections
1359 void bfd_map_over_sections
1361 void (*func) (bfd *abfd, asection *sect, void *obj),
1365 Call the provided function @var{func} for each section
1366 attached to the BFD @var{abfd}, passing @var{obj} as an
1367 argument. The function will be called as if by
1369 | func (abfd, the_section, obj);
1371 This is the preferred method for iterating over sections; an
1372 alternative would be to use a loop:
1375 | for (p = abfd->sections; p != NULL; p = p->next)
1376 | func (abfd, p, ...)
1381 bfd_map_over_sections (bfd *abfd,
1382 void (*operation) (bfd *, asection *, void *),
1388 for (sect = abfd->sections; sect != NULL; i++, sect = sect->next)
1389 (*operation) (abfd, sect, user_storage);
1391 if (i != abfd->section_count) /* Debugging */
1397 bfd_sections_find_if
1400 asection *bfd_sections_find_if
1402 bfd_boolean (*operation) (bfd *abfd, asection *sect, void *obj),
1406 Call the provided function @var{operation} for each section
1407 attached to the BFD @var{abfd}, passing @var{obj} as an
1408 argument. The function will be called as if by
1410 | operation (abfd, the_section, obj);
1412 It returns the first section for which @var{operation} returns true.
1417 bfd_sections_find_if (bfd *abfd,
1418 bfd_boolean (*operation) (bfd *, asection *, void *),
1423 for (sect = abfd->sections; sect != NULL; sect = sect->next)
1424 if ((*operation) (abfd, sect, user_storage))
1432 bfd_set_section_size
1435 bfd_boolean bfd_set_section_size
1436 (bfd *abfd, asection *sec, bfd_size_type val);
1439 Set @var{sec} to the size @var{val}. If the operation is
1440 ok, then <<TRUE>> is returned, else <<FALSE>>.
1442 Possible error returns:
1443 o <<bfd_error_invalid_operation>> -
1444 Writing has started to the BFD, so setting the size is invalid.
1449 bfd_set_section_size (bfd *abfd, sec_ptr ptr, bfd_size_type val)
1451 /* Once you've started writing to any section you cannot create or change
1452 the size of any others. */
1454 if (abfd->output_has_begun)
1456 bfd_set_error (bfd_error_invalid_operation);
1466 bfd_set_section_contents
1469 bfd_boolean bfd_set_section_contents
1470 (bfd *abfd, asection *section, const void *data,
1471 file_ptr offset, bfd_size_type count);
1474 Sets the contents of the section @var{section} in BFD
1475 @var{abfd} to the data starting in memory at @var{data}. The
1476 data is written to the output section starting at offset
1477 @var{offset} for @var{count} octets.
1479 Normally <<TRUE>> is returned, else <<FALSE>>. Possible error
1481 o <<bfd_error_no_contents>> -
1482 The output section does not have the <<SEC_HAS_CONTENTS>>
1483 attribute, so nothing can be written to it.
1486 This routine is front end to the back end function
1487 <<_bfd_set_section_contents>>.
1492 bfd_set_section_contents (bfd *abfd,
1494 const void *location,
1496 bfd_size_type count)
1500 if (!(bfd_get_section_flags (abfd, section) & SEC_HAS_CONTENTS))
1502 bfd_set_error (bfd_error_no_contents);
1507 if ((bfd_size_type) offset > sz
1509 || offset + count > sz
1510 || count != (size_t) count)
1512 bfd_set_error (bfd_error_bad_value);
1516 if (!bfd_write_p (abfd))
1518 bfd_set_error (bfd_error_invalid_operation);
1522 /* Record a copy of the data in memory if desired. */
1523 if (section->contents
1524 && location != section->contents + offset)
1525 memcpy (section->contents + offset, location, (size_t) count);
1527 if (BFD_SEND (abfd, _bfd_set_section_contents,
1528 (abfd, section, location, offset, count)))
1530 abfd->output_has_begun = TRUE;
1539 bfd_get_section_contents
1542 bfd_boolean bfd_get_section_contents
1543 (bfd *abfd, asection *section, void *location, file_ptr offset,
1544 bfd_size_type count);
1547 Read data from @var{section} in BFD @var{abfd}
1548 into memory starting at @var{location}. The data is read at an
1549 offset of @var{offset} from the start of the input section,
1550 and is read for @var{count} bytes.
1552 If the contents of a constructor with the <<SEC_CONSTRUCTOR>>
1553 flag set are requested or if the section does not have the
1554 <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled
1555 with zeroes. If no errors occur, <<TRUE>> is returned, else
1560 bfd_get_section_contents (bfd *abfd,
1564 bfd_size_type count)
1568 if (section->flags & SEC_CONSTRUCTOR)
1570 memset (location, 0, (size_t) count);
1574 if (abfd->direction != write_direction && section->rawsize != 0)
1575 sz = section->rawsize;
1578 if ((bfd_size_type) offset > sz
1580 || offset + count > sz
1581 || count != (size_t) count)
1583 bfd_set_error (bfd_error_bad_value);
1591 if ((section->flags & SEC_HAS_CONTENTS) == 0)
1593 memset (location, 0, (size_t) count);
1597 if ((section->flags & SEC_IN_MEMORY) != 0)
1599 if (section->contents == NULL)
1601 /* This can happen because of errors earlier on in the linking process.
1602 We do not want to seg-fault here, so clear the flag and return an
1604 section->flags &= ~ SEC_IN_MEMORY;
1605 bfd_set_error (bfd_error_invalid_operation);
1609 memmove (location, section->contents + offset, (size_t) count);
1613 return BFD_SEND (abfd, _bfd_get_section_contents,
1614 (abfd, section, location, offset, count));
1619 bfd_malloc_and_get_section
1622 bfd_boolean bfd_malloc_and_get_section
1623 (bfd *abfd, asection *section, bfd_byte **buf);
1626 Read all data from @var{section} in BFD @var{abfd}
1627 into a buffer, *@var{buf}, malloc'd by this function.
1631 bfd_malloc_and_get_section (bfd *abfd, sec_ptr sec, bfd_byte **buf)
1634 return bfd_get_full_section_contents (abfd, sec, buf);
1638 bfd_copy_private_section_data
1641 bfd_boolean bfd_copy_private_section_data
1642 (bfd *ibfd, asection *isec, bfd *obfd, asection *osec);
1645 Copy private section information from @var{isec} in the BFD
1646 @var{ibfd} to the section @var{osec} in the BFD @var{obfd}.
1647 Return <<TRUE>> on success, <<FALSE>> on error. Possible error
1650 o <<bfd_error_no_memory>> -
1651 Not enough memory exists to create private data for @var{osec}.
1653 .#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \
1654 . BFD_SEND (obfd, _bfd_copy_private_section_data, \
1655 . (ibfd, isection, obfd, osection))
1660 bfd_generic_is_group_section
1663 bfd_boolean bfd_generic_is_group_section (bfd *, const asection *sec);
1666 Returns TRUE if @var{sec} is a member of a group.
1670 bfd_generic_is_group_section (bfd *abfd ATTRIBUTE_UNUSED,
1671 const asection *sec ATTRIBUTE_UNUSED)
1678 bfd_generic_discard_group
1681 bfd_boolean bfd_generic_discard_group (bfd *abfd, asection *group);
1684 Remove all members of @var{group} from the output.
1688 bfd_generic_discard_group (bfd *abfd ATTRIBUTE_UNUSED,
1689 asection *group ATTRIBUTE_UNUSED)
1695 _bfd_nowrite_set_section_contents (bfd *abfd,
1696 sec_ptr section ATTRIBUTE_UNUSED,
1697 const void *location ATTRIBUTE_UNUSED,
1698 file_ptr offset ATTRIBUTE_UNUSED,
1699 bfd_size_type count ATTRIBUTE_UNUSED)
1701 return _bfd_bool_bfd_false_error (abfd);