1 /* Object file "section" support for the BFD library.
2 Copyright (C) 1990-2022 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
71 Section Output, typedef asection, Section Input, Sections
76 To write a new object style BFD, the various sections to be
77 written have to be created. They are attached to the BFD in
78 the same way as input sections; data is written to the
79 sections using <<bfd_set_section_contents>>.
81 Any program that creates or combines sections (e.g., the assembler
82 and linker) must use the <<asection>> fields <<output_section>> and
83 <<output_offset>> to indicate the file sections to which each
84 section must be written. (If the section is being created from
85 scratch, <<output_section>> should probably point to the section
86 itself and <<output_offset>> should probably be zero.)
88 The data to be written comes from input sections attached
89 (via <<output_section>> pointers) to
90 the output sections. The output section structure can be
91 considered a filter for the input section: the output section
92 determines the vma of the output data and the name, but the
93 input section determines the offset into the output section of
94 the data to be written.
96 E.g., to create a section "O", starting at 0x100, 0x123 long,
97 containing two subsections, "A" at offset 0x0 (i.e., at vma
98 0x100) and "B" at offset 0x20 (i.e., at vma 0x120) the <<asection>>
99 structures would look like:
104 | output_section -----------> section name "O"
106 | section name "B" | size 0x123
107 | output_offset 0x20 |
109 | output_section --------|
114 The data within a section is stored in a @dfn{link_order}.
115 These are much like the fixups in <<gas>>. The link_order
116 abstraction allows a section to grow and shrink within itself.
118 A link_order knows how big it is, and which is the next
119 link_order and where the raw data for it is; it also points to
120 a list of relocations which apply to it.
122 The link_order is used by the linker to perform relaxing on
123 final code. The compiler creates code which is as big as
124 necessary to make it work without relaxing, and the user can
125 select whether to relax. Sometimes relaxing takes a lot of
126 time. The linker runs around the relocations to see if any
127 are attached to data which can be shrunk, if so it does it on
128 a link_order by link_order basis.
140 typedef asection, section prototypes, Section Output, Sections
144 Here is the section structure:
148 .typedef struct bfd_section
150 . {* The name of the section; the name isn't a copy, the pointer is
151 . the same as that passed to bfd_make_section. *}
154 . {* A unique sequence number. *}
157 . {* A unique section number which can be used by assembler to
158 . distinguish different sections with the same section name. *}
159 . unsigned int section_id;
161 . {* Which section in the bfd; 0..n-1 as sections are created in a bfd. *}
162 . unsigned int index;
164 . {* The next section in the list belonging to the BFD, or NULL. *}
165 . struct bfd_section *next;
167 . {* The previous section in the list belonging to the BFD, or NULL. *}
168 . struct bfd_section *prev;
170 . {* The field flags contains attributes of the section. Some
171 . flags are read in from the object file, and some are
172 . synthesized from other information. *}
175 .#define SEC_NO_FLAGS 0x0
177 . {* Tells the OS to allocate space for this section when loading.
178 . This is clear for a section containing debug information only. *}
179 .#define SEC_ALLOC 0x1
181 . {* Tells the OS to load the section from the file when loading.
182 . This is clear for a .bss section. *}
183 .#define SEC_LOAD 0x2
185 . {* The section contains data still to be relocated, so there is
186 . some relocation information too. *}
187 .#define SEC_RELOC 0x4
189 . {* A signal to the OS that the section contains read only data. *}
190 .#define SEC_READONLY 0x8
192 . {* The section contains code only. *}
193 .#define SEC_CODE 0x10
195 . {* The section contains data only. *}
196 .#define SEC_DATA 0x20
198 . {* The section will reside in ROM. *}
199 .#define SEC_ROM 0x40
201 . {* The section contains constructor information. This section
202 . type is used by the linker to create lists of constructors and
203 . destructors used by <<g++>>. When a back end sees a symbol
204 . which should be used in a constructor list, it creates a new
205 . section for the type of name (e.g., <<__CTOR_LIST__>>), attaches
206 . the symbol to it, and builds a relocation. To build the lists
207 . of constructors, all the linker has to do is catenate all the
208 . sections called <<__CTOR_LIST__>> and relocate the data
209 . contained within - exactly the operations it would peform on
211 .#define SEC_CONSTRUCTOR 0x80
213 . {* The section has contents - a data section could be
214 . <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>; a debug section could be
215 . <<SEC_HAS_CONTENTS>> *}
216 .#define SEC_HAS_CONTENTS 0x100
218 . {* An instruction to the linker to not output the section
219 . even if it has information which would normally be written. *}
220 .#define SEC_NEVER_LOAD 0x200
222 . {* The section contains thread local data. *}
223 .#define SEC_THREAD_LOCAL 0x400
225 . {* The section's size is fixed. Generic linker code will not
226 . recalculate it and it is up to whoever has set this flag to
227 . get the size right. *}
228 .#define SEC_FIXED_SIZE 0x800
230 . {* The section contains common symbols (symbols may be defined
231 . multiple times, the value of a symbol is the amount of
232 . space it requires, and the largest symbol value is the one
233 . used). Most targets have exactly one of these (which we
234 . translate to bfd_com_section_ptr), but ECOFF has two. *}
235 .#define SEC_IS_COMMON 0x1000
237 . {* The section contains only debugging information. For
238 . example, this is set for ELF .debug and .stab sections.
239 . strip tests this flag to see if a section can be
241 .#define SEC_DEBUGGING 0x2000
243 . {* The contents of this section are held in memory pointed to
244 . by the contents field. This is checked by bfd_get_section_contents,
245 . and the data is retrieved from memory if appropriate. *}
246 .#define SEC_IN_MEMORY 0x4000
248 . {* The contents of this section are to be excluded by the
249 . linker for executable and shared objects unless those
250 . objects are to be further relocated. *}
251 .#define SEC_EXCLUDE 0x8000
253 . {* The contents of this section are to be sorted based on the sum of
254 . the symbol and addend values specified by the associated relocation
255 . entries. Entries without associated relocation entries will be
256 . appended to the end of the section in an unspecified order. *}
257 .#define SEC_SORT_ENTRIES 0x10000
259 . {* When linking, duplicate sections of the same name should be
260 . discarded, rather than being combined into a single section as
261 . is usually done. This is similar to how common symbols are
262 . handled. See SEC_LINK_DUPLICATES below. *}
263 .#define SEC_LINK_ONCE 0x20000
265 . {* If SEC_LINK_ONCE is set, this bitfield describes how the linker
266 . should handle duplicate sections. *}
267 .#define SEC_LINK_DUPLICATES 0xc0000
269 . {* This value for SEC_LINK_DUPLICATES means that duplicate
270 . sections with the same name should simply be discarded. *}
271 .#define SEC_LINK_DUPLICATES_DISCARD 0x0
273 . {* This value for SEC_LINK_DUPLICATES means that the linker
274 . should warn if there are any duplicate sections, although
275 . it should still only link one copy. *}
276 .#define SEC_LINK_DUPLICATES_ONE_ONLY 0x40000
278 . {* This value for SEC_LINK_DUPLICATES means that the linker
279 . should warn if any duplicate sections are a different size. *}
280 .#define SEC_LINK_DUPLICATES_SAME_SIZE 0x80000
282 . {* This value for SEC_LINK_DUPLICATES means that the linker
283 . should warn if any duplicate sections contain different
285 .#define SEC_LINK_DUPLICATES_SAME_CONTENTS \
286 . (SEC_LINK_DUPLICATES_ONE_ONLY | SEC_LINK_DUPLICATES_SAME_SIZE)
288 . {* This section was created by the linker as part of dynamic
289 . relocation or other arcane processing. It is skipped when
290 . going through the first-pass output, trusting that someone
291 . else up the line will take care of it later. *}
292 .#define SEC_LINKER_CREATED 0x100000
294 . {* This section contains a section ID to distinguish different
295 . sections with the same section name. *}
296 .#define SEC_ASSEMBLER_SECTION_ID 0x100000
298 . {* This section should not be subject to garbage collection.
299 . Also set to inform the linker that this section should not be
300 . listed in the link map as discarded. *}
301 .#define SEC_KEEP 0x200000
303 . {* This section contains "short" data, and should be placed
305 .#define SEC_SMALL_DATA 0x400000
307 . {* Attempt to merge identical entities in the section.
308 . Entity size is given in the entsize field. *}
309 .#define SEC_MERGE 0x800000
311 . {* If given with SEC_MERGE, entities to merge are zero terminated
312 . strings where entsize specifies character size instead of fixed
314 .#define SEC_STRINGS 0x1000000
316 . {* This section contains data about section groups. *}
317 .#define SEC_GROUP 0x2000000
319 . {* The section is a COFF shared library section. This flag is
320 . only for the linker. If this type of section appears in
321 . the input file, the linker must copy it to the output file
322 . without changing the vma or size. FIXME: Although this
323 . was originally intended to be general, it really is COFF
324 . specific (and the flag was renamed to indicate this). It
325 . might be cleaner to have some more general mechanism to
326 . allow the back end to control what the linker does with
328 .#define SEC_COFF_SHARED_LIBRARY 0x4000000
330 . {* This input section should be copied to output in reverse order
331 . as an array of pointers. This is for ELF linker internal use
333 .#define SEC_ELF_REVERSE_COPY 0x4000000
335 . {* This section contains data which may be shared with other
336 . executables or shared objects. This is for COFF only. *}
337 .#define SEC_COFF_SHARED 0x8000000
339 . {* This section should be compressed. This is for ELF linker
340 . internal use only. *}
341 .#define SEC_ELF_COMPRESS 0x8000000
343 . {* When a section with this flag is being linked, then if the size of
344 . the input section is less than a page, it should not cross a page
345 . boundary. If the size of the input section is one page or more,
346 . it should be aligned on a page boundary. This is for TI
347 . TMS320C54X only. *}
348 .#define SEC_TIC54X_BLOCK 0x10000000
350 . {* This section should be renamed. This is for ELF linker
351 . internal use only. *}
352 .#define SEC_ELF_RENAME 0x10000000
354 . {* Conditionally link this section; do not link if there are no
355 . references found to any symbol in the section. This is for TI
356 . TMS320C54X only. *}
357 .#define SEC_TIC54X_CLINK 0x20000000
359 . {* This section contains vliw code. This is for Toshiba MeP only. *}
360 .#define SEC_MEP_VLIW 0x20000000
362 . {* All symbols, sizes and relocations in this section are octets
363 . instead of bytes. Required for DWARF debug sections as DWARF
364 . information is organized in octets, not bytes. *}
365 .#define SEC_ELF_OCTETS 0x40000000
367 . {* Indicate that section has the no read flag set. This happens
368 . when memory read flag isn't set. *}
369 .#define SEC_COFF_NOREAD 0x40000000
371 . {* Indicate that section has the purecode flag set. *}
372 .#define SEC_ELF_PURECODE 0x80000000
374 . {* End of section flags. *}
376 . {* Some internal packed boolean fields. *}
378 . {* See the vma field. *}
379 . unsigned int user_set_vma : 1;
381 . {* A mark flag used by some of the linker backends. *}
382 . unsigned int linker_mark : 1;
384 . {* Another mark flag used by some of the linker backends. Set for
385 . output sections that have an input section. *}
386 . unsigned int linker_has_input : 1;
388 . {* Mark flag used by some linker backends for garbage collection. *}
389 . unsigned int gc_mark : 1;
391 . {* Section compression status. *}
392 . unsigned int compress_status : 2;
393 .#define COMPRESS_SECTION_NONE 0
394 .#define COMPRESS_SECTION_DONE 1
395 .#define DECOMPRESS_SECTION_SIZED 2
397 . {* The following flags are used by the ELF linker. *}
399 . {* Mark sections which have been allocated to segments. *}
400 . unsigned int segment_mark : 1;
402 . {* Type of sec_info information. *}
403 . unsigned int sec_info_type:3;
404 .#define SEC_INFO_TYPE_NONE 0
405 .#define SEC_INFO_TYPE_STABS 1
406 .#define SEC_INFO_TYPE_MERGE 2
407 .#define SEC_INFO_TYPE_EH_FRAME 3
408 .#define SEC_INFO_TYPE_JUST_SYMS 4
409 .#define SEC_INFO_TYPE_TARGET 5
410 .#define SEC_INFO_TYPE_EH_FRAME_ENTRY 6
412 . {* Nonzero if this section uses RELA relocations, rather than REL. *}
413 . unsigned int use_rela_p:1;
415 . {* Bits used by various backends. The generic code doesn't touch
418 . unsigned int sec_flg0:1;
419 . unsigned int sec_flg1:1;
420 . unsigned int sec_flg2:1;
421 . unsigned int sec_flg3:1;
422 . unsigned int sec_flg4:1;
423 . unsigned int sec_flg5:1;
425 . {* End of internal packed boolean fields. *}
427 . {* The virtual memory address of the section - where it will be
428 . at run time. The symbols are relocated against this. The
429 . user_set_vma flag is maintained by bfd; if it's not set, the
430 . backend can assign addresses (for example, in <<a.out>>, where
431 . the default address for <<.data>> is dependent on the specific
432 . target and various flags). *}
435 . {* The load address of the section - where it would be in a
436 . rom image; really only used for writing section header
440 . {* The size of the section in *octets*, as it will be output.
441 . Contains a value even if the section has no contents (e.g., the
442 . size of <<.bss>>). *}
443 . bfd_size_type size;
445 . {* For input sections, the original size on disk of the section, in
446 . octets. This field should be set for any section whose size is
447 . changed by linker relaxation. It is required for sections where
448 . the linker relaxation scheme doesn't cache altered section and
449 . reloc contents (stabs, eh_frame, SEC_MERGE, some coff relaxing
450 . targets), and thus the original size needs to be kept to read the
451 . section multiple times. For output sections, rawsize holds the
452 . section size calculated on a previous linker relaxation pass. *}
453 . bfd_size_type rawsize;
455 . {* The compressed size of the section in octets. *}
456 . bfd_size_type compressed_size;
458 . {* Relaxation table. *}
459 . struct relax_table *relax;
461 . {* Count of used relaxation table entries. *}
465 . {* If this section is going to be output, then this value is the
466 . offset in *bytes* into the output section of the first byte in the
467 . input section (byte ==> smallest addressable unit on the
468 . target). In most cases, if this was going to start at the
469 . 100th octet (8-bit quantity) in the output section, this value
470 . would be 100. However, if the target byte size is 16 bits
471 . (bfd_octets_per_byte is "2"), this value would be 50. *}
472 . bfd_vma output_offset;
474 . {* The output section through which to map on output. *}
475 . struct bfd_section *output_section;
477 . {* The alignment requirement of the section, as an exponent of 2 -
478 . e.g., 3 aligns to 2^3 (or 8). *}
479 . unsigned int alignment_power;
481 . {* If an input section, a pointer to a vector of relocation
482 . records for the data in this section. *}
483 . struct reloc_cache_entry *relocation;
485 . {* If an output section, a pointer to a vector of pointers to
486 . relocation records for the data in this section. *}
487 . struct reloc_cache_entry **orelocation;
489 . {* The number of relocation records in one of the above. *}
490 . unsigned reloc_count;
492 . {* Information below is back end specific - and not always used
495 . {* File position of section data. *}
498 . {* File position of relocation info. *}
499 . file_ptr rel_filepos;
501 . {* File position of line data. *}
502 . file_ptr line_filepos;
504 . {* Pointer to data for applications. *}
507 . {* If the SEC_IN_MEMORY flag is set, this points to the actual
509 . unsigned char *contents;
511 . {* Attached line number information. *}
514 . {* Number of line number records. *}
515 . unsigned int lineno_count;
517 . {* Entity size for merging purposes. *}
518 . unsigned int entsize;
520 . {* Points to the kept section if this section is a link-once section,
521 . and is discarded. *}
522 . struct bfd_section *kept_section;
524 . {* When a section is being output, this value changes as more
525 . linenumbers are written out. *}
526 . file_ptr moving_line_filepos;
528 . {* What the section number is in the target world. *}
533 . {* If this is a constructor section then here is a list of the
534 . relocations created to relocate items within it. *}
535 . struct relent_chain *constructor_chain;
537 . {* The BFD which owns the section. *}
540 . {* A symbol which points at this section only. *}
541 . struct bfd_symbol *symbol;
542 . struct bfd_symbol **symbol_ptr_ptr;
544 . {* Early in the link process, map_head and map_tail are used to build
545 . a list of input sections attached to an output section. Later,
546 . output sections use these fields for a list of bfd_link_order
547 . structs. The linked_to_symbol_name field is for ELF assembler
550 . struct bfd_link_order *link_order;
551 . struct bfd_section *s;
552 . const char *linked_to_symbol_name;
553 . } map_head, map_tail;
554 . {* Points to the output section this section is already assigned to, if any.
555 . This is used when support for non-contiguous memory regions is enabled. *}
556 . struct bfd_section *already_assigned;
560 .{* Relax table contains information about instructions which can
561 . be removed by relaxation -- replacing a long address with a
563 .struct relax_table {
564 . {* Address where bytes may be deleted. *}
567 . {* Number of bytes to be deleted. *}
571 .static inline const char *
572 .bfd_section_name (const asection *sec)
577 .static inline bfd_size_type
578 .bfd_section_size (const asection *sec)
583 .static inline bfd_vma
584 .bfd_section_vma (const asection *sec)
589 .static inline bfd_vma
590 .bfd_section_lma (const asection *sec)
595 .static inline unsigned int
596 .bfd_section_alignment (const asection *sec)
598 . return sec->alignment_power;
601 .static inline flagword
602 .bfd_section_flags (const asection *sec)
607 .static inline void *
608 .bfd_section_userdata (const asection *sec)
610 . return sec->userdata;
613 .bfd_is_com_section (const asection *sec)
615 . return (sec->flags & SEC_IS_COMMON) != 0;
618 .{* Note: the following are provided as inline functions rather than macros
619 . because not all callers use the return value. A macro implementation
620 . would use a comma expression, eg: "((ptr)->foo = val, TRUE)" and some
621 . compilers will complain about comma expressions that have no effect. *}
623 .bfd_set_section_userdata (asection *sec, void *val)
625 . sec->userdata = val;
630 .bfd_set_section_vma (asection *sec, bfd_vma val)
632 . sec->vma = sec->lma = val;
633 . sec->user_set_vma = true;
638 .bfd_set_section_lma (asection *sec, bfd_vma val)
645 .bfd_set_section_alignment (asection *sec, unsigned int val)
647 . sec->alignment_power = val;
651 .{* These sections are global, and are managed by BFD. The application
652 . and target back end are not permitted to change the values in
654 .extern asection _bfd_std_section[4];
656 .#define BFD_ABS_SECTION_NAME "*ABS*"
657 .#define BFD_UND_SECTION_NAME "*UND*"
658 .#define BFD_COM_SECTION_NAME "*COM*"
659 .#define BFD_IND_SECTION_NAME "*IND*"
661 .{* Pointer to the common section. *}
662 .#define bfd_com_section_ptr (&_bfd_std_section[0])
663 .{* Pointer to the undefined section. *}
664 .#define bfd_und_section_ptr (&_bfd_std_section[1])
665 .{* Pointer to the absolute section. *}
666 .#define bfd_abs_section_ptr (&_bfd_std_section[2])
667 .{* Pointer to the indirect section. *}
668 .#define bfd_ind_section_ptr (&_bfd_std_section[3])
671 .bfd_is_und_section (const asection *sec)
673 . return sec == bfd_und_section_ptr;
677 .bfd_is_abs_section (const asection *sec)
679 . return sec == bfd_abs_section_ptr;
683 .bfd_is_ind_section (const asection *sec)
685 . return sec == bfd_ind_section_ptr;
689 .bfd_is_const_section (const asection *sec)
691 . return (sec >= _bfd_std_section
692 . && sec < _bfd_std_section + (sizeof (_bfd_std_section)
693 . / sizeof (_bfd_std_section[0])));
696 .{* Return TRUE if input section SEC has been discarded. *}
698 .discarded_section (const asection *sec)
700 . return (!bfd_is_abs_section (sec)
701 . && bfd_is_abs_section (sec->output_section)
702 . && sec->sec_info_type != SEC_INFO_TYPE_MERGE
703 . && sec->sec_info_type != SEC_INFO_TYPE_JUST_SYMS);
706 .#define BFD_FAKE_SECTION(SEC, SYM, NAME, IDX, FLAGS) \
707 . {* name, id, section_id, index, next, prev, flags, user_set_vma, *} \
708 . { NAME, IDX, 0, 0, NULL, NULL, FLAGS, 0, \
710 . {* linker_mark, linker_has_input, gc_mark, decompress_status, *} \
713 . {* segment_mark, sec_info_type, use_rela_p, *} \
716 . {* sec_flg0, sec_flg1, sec_flg2, sec_flg3, sec_flg4, sec_flg5, *} \
717 . 0, 0, 0, 0, 0, 0, \
719 . {* vma, lma, size, rawsize, compressed_size, relax, relax_count, *} \
720 . 0, 0, 0, 0, 0, 0, 0, \
722 . {* output_offset, output_section, alignment_power, *} \
725 . {* relocation, orelocation, reloc_count, filepos, rel_filepos, *} \
726 . NULL, NULL, 0, 0, 0, \
728 . {* line_filepos, userdata, contents, lineno, lineno_count, *} \
729 . 0, NULL, NULL, NULL, 0, \
731 . {* entsize, kept_section, moving_line_filepos, *} \
734 . {* target_index, used_by_bfd, constructor_chain, owner, *} \
735 . 0, NULL, NULL, NULL, \
737 . {* symbol, symbol_ptr_ptr, *} \
738 . (struct bfd_symbol *) SYM, &SEC.symbol, \
740 . {* map_head, map_tail, already_assigned *} \
741 . { NULL }, { NULL }, NULL \
745 .{* We use a macro to initialize the static asymbol structures because
746 . traditional C does not permit us to initialize a union member while
747 . gcc warns if we don't initialize it.
748 . the_bfd, name, value, attr, section [, udata] *}
750 .#define GLOBAL_SYM_INIT(NAME, SECTION) \
751 . { 0, NAME, 0, BSF_SECTION_SYM, SECTION, { 0 }}
753 .#define GLOBAL_SYM_INIT(NAME, SECTION) \
754 . { 0, NAME, 0, BSF_SECTION_SYM, SECTION }
759 /* These symbols are global, not specific to any BFD. Therefore, anything
760 that tries to change them is broken, and should be repaired. */
762 static const asymbol global_syms
[] =
764 GLOBAL_SYM_INIT (BFD_COM_SECTION_NAME
, bfd_com_section_ptr
),
765 GLOBAL_SYM_INIT (BFD_UND_SECTION_NAME
, bfd_und_section_ptr
),
766 GLOBAL_SYM_INIT (BFD_ABS_SECTION_NAME
, bfd_abs_section_ptr
),
767 GLOBAL_SYM_INIT (BFD_IND_SECTION_NAME
, bfd_ind_section_ptr
)
770 #define STD_SECTION(NAME, IDX, FLAGS) \
771 BFD_FAKE_SECTION(_bfd_std_section[IDX], &global_syms[IDX], NAME, IDX, FLAGS)
773 asection _bfd_std_section
[] = {
774 STD_SECTION (BFD_COM_SECTION_NAME
, 0, SEC_IS_COMMON
),
775 STD_SECTION (BFD_UND_SECTION_NAME
, 1, 0),
776 STD_SECTION (BFD_ABS_SECTION_NAME
, 2, 0),
777 STD_SECTION (BFD_IND_SECTION_NAME
, 3, 0)
781 /* Initialize an entry in the section hash table. */
783 struct bfd_hash_entry
*
784 bfd_section_hash_newfunc (struct bfd_hash_entry
*entry
,
785 struct bfd_hash_table
*table
,
788 /* Allocate the structure if it has not already been allocated by a
792 entry
= (struct bfd_hash_entry
*)
793 bfd_hash_allocate (table
, sizeof (struct section_hash_entry
));
798 /* Call the allocation method of the superclass. */
799 entry
= bfd_hash_newfunc (entry
, table
, string
);
801 memset (&((struct section_hash_entry
*) entry
)->section
, 0,
807 #define section_hash_lookup(table, string, create, copy) \
808 ((struct section_hash_entry *) \
809 bfd_hash_lookup ((table), (string), (create), (copy)))
811 /* Create a symbol whose only job is to point to this section. This
812 is useful for things like relocs which are relative to the base
816 _bfd_generic_new_section_hook (bfd
*abfd
, asection
*newsect
)
818 newsect
->symbol
= bfd_make_empty_symbol (abfd
);
819 if (newsect
->symbol
== NULL
)
822 newsect
->symbol
->name
= newsect
->name
;
823 newsect
->symbol
->value
= 0;
824 newsect
->symbol
->section
= newsect
;
825 newsect
->symbol
->flags
= BSF_SECTION_SYM
;
827 newsect
->symbol_ptr_ptr
= &newsect
->symbol
;
831 unsigned int _bfd_section_id
= 0x10; /* id 0 to 3 used by STD_SECTION. */
833 /* Initializes a new section. NEWSECT->NAME is already set. */
836 bfd_section_init (bfd
*abfd
, asection
*newsect
)
838 newsect
->id
= _bfd_section_id
;
839 newsect
->index
= abfd
->section_count
;
840 newsect
->owner
= abfd
;
842 if (! BFD_SEND (abfd
, _new_section_hook
, (abfd
, newsect
)))
846 abfd
->section_count
++;
847 bfd_section_list_append (abfd
, newsect
);
854 section prototypes, , typedef asection, Sections
858 These are the functions exported by the section handling part of BFD.
863 bfd_section_list_clear
866 void bfd_section_list_clear (bfd *);
869 Clears the section list, and also resets the section count and
874 bfd_section_list_clear (bfd
*abfd
)
876 abfd
->sections
= NULL
;
877 abfd
->section_last
= NULL
;
878 abfd
->section_count
= 0;
879 memset (abfd
->section_htab
.table
, 0,
880 abfd
->section_htab
.size
* sizeof (struct bfd_hash_entry
*));
881 abfd
->section_htab
.count
= 0;
886 bfd_get_section_by_name
889 asection *bfd_get_section_by_name (bfd *abfd, const char *name);
892 Return the most recently created section attached to @var{abfd}
893 named @var{name}. Return NULL if no such section exists.
897 bfd_get_section_by_name (bfd
*abfd
, const char *name
)
899 struct section_hash_entry
*sh
;
904 sh
= section_hash_lookup (&abfd
->section_htab
, name
, false, false);
913 bfd_get_next_section_by_name
916 asection *bfd_get_next_section_by_name (bfd *ibfd, asection *sec);
919 Given @var{sec} is a section returned by @code{bfd_get_section_by_name},
920 return the next most recently created section attached to the same
921 BFD with the same name, or if no such section exists in the same BFD and
922 IBFD is non-NULL, the next section with the same name in any input
923 BFD following IBFD. Return NULL on finding no section.
927 bfd_get_next_section_by_name (bfd
*ibfd
, asection
*sec
)
929 struct section_hash_entry
*sh
;
933 sh
= ((struct section_hash_entry
*)
934 ((char *) sec
- offsetof (struct section_hash_entry
, section
)));
936 hash
= sh
->root
.hash
;
938 for (sh
= (struct section_hash_entry
*) sh
->root
.next
;
940 sh
= (struct section_hash_entry
*) sh
->root
.next
)
941 if (sh
->root
.hash
== hash
942 && strcmp (sh
->root
.string
, name
) == 0)
947 while ((ibfd
= ibfd
->link
.next
) != NULL
)
949 asection
*s
= bfd_get_section_by_name (ibfd
, name
);
960 bfd_get_linker_section
963 asection *bfd_get_linker_section (bfd *abfd, const char *name);
966 Return the linker created section attached to @var{abfd}
967 named @var{name}. Return NULL if no such section exists.
971 bfd_get_linker_section (bfd
*abfd
, const char *name
)
973 asection
*sec
= bfd_get_section_by_name (abfd
, name
);
975 while (sec
!= NULL
&& (sec
->flags
& SEC_LINKER_CREATED
) == 0)
976 sec
= bfd_get_next_section_by_name (NULL
, sec
);
982 bfd_get_section_by_name_if
985 asection *bfd_get_section_by_name_if
988 bool (*func) (bfd *abfd, asection *sect, void *obj),
992 Call the provided function @var{func} for each section
993 attached to the BFD @var{abfd} whose name matches @var{name},
994 passing @var{obj} as an argument. The function will be called
997 | func (abfd, the_section, obj);
999 It returns the first section for which @var{func} returns true,
1005 bfd_get_section_by_name_if (bfd
*abfd
, const char *name
,
1006 bool (*operation
) (bfd
*, asection
*, void *),
1009 struct section_hash_entry
*sh
;
1015 sh
= section_hash_lookup (&abfd
->section_htab
, name
, false, false);
1019 hash
= sh
->root
.hash
;
1020 for (; sh
!= NULL
; sh
= (struct section_hash_entry
*) sh
->root
.next
)
1021 if (sh
->root
.hash
== hash
1022 && strcmp (sh
->root
.string
, name
) == 0
1023 && (*operation
) (abfd
, &sh
->section
, user_storage
))
1024 return &sh
->section
;
1031 bfd_get_unique_section_name
1034 char *bfd_get_unique_section_name
1035 (bfd *abfd, const char *templat, int *count);
1038 Invent a section name that is unique in @var{abfd} by tacking
1039 a dot and a digit suffix onto the original @var{templat}. If
1040 @var{count} is non-NULL, then it specifies the first number
1041 tried as a suffix to generate a unique name. The value
1042 pointed to by @var{count} will be incremented in this case.
1046 bfd_get_unique_section_name (bfd
*abfd
, const char *templat
, int *count
)
1052 len
= strlen (templat
);
1053 sname
= (char *) bfd_malloc (len
+ 8);
1056 memcpy (sname
, templat
, len
);
1063 /* If we have a million sections, something is badly wrong. */
1066 sprintf (sname
+ len
, ".%d", num
++);
1068 while (section_hash_lookup (&abfd
->section_htab
, sname
, false, false));
1077 bfd_make_section_old_way
1080 asection *bfd_make_section_old_way (bfd *abfd, const char *name);
1083 Create a new empty section called @var{name}
1084 and attach it to the end of the chain of sections for the
1085 BFD @var{abfd}. An attempt to create a section with a name which
1086 is already in use returns its pointer without changing the
1089 It has the funny name since this is the way it used to be
1090 before it was rewritten....
1092 Possible errors are:
1093 o <<bfd_error_invalid_operation>> -
1094 If output has already started for this BFD.
1095 o <<bfd_error_no_memory>> -
1096 If memory allocation fails.
1101 bfd_make_section_old_way (bfd
*abfd
, const char *name
)
1105 if (abfd
->output_has_begun
)
1107 bfd_set_error (bfd_error_invalid_operation
);
1111 if (strcmp (name
, BFD_ABS_SECTION_NAME
) == 0)
1112 newsect
= bfd_abs_section_ptr
;
1113 else if (strcmp (name
, BFD_COM_SECTION_NAME
) == 0)
1114 newsect
= bfd_com_section_ptr
;
1115 else if (strcmp (name
, BFD_UND_SECTION_NAME
) == 0)
1116 newsect
= bfd_und_section_ptr
;
1117 else if (strcmp (name
, BFD_IND_SECTION_NAME
) == 0)
1118 newsect
= bfd_ind_section_ptr
;
1121 struct section_hash_entry
*sh
;
1123 sh
= section_hash_lookup (&abfd
->section_htab
, name
, true, false);
1127 newsect
= &sh
->section
;
1128 if (newsect
->name
!= NULL
)
1130 /* Section already exists. */
1134 newsect
->name
= name
;
1135 return bfd_section_init (abfd
, newsect
);
1138 /* Call new_section_hook when "creating" the standard abs, com, und
1139 and ind sections to tack on format specific section data.
1140 Also, create a proper section symbol. */
1141 if (! BFD_SEND (abfd
, _new_section_hook
, (abfd
, newsect
)))
1148 bfd_make_section_anyway_with_flags
1151 asection *bfd_make_section_anyway_with_flags
1152 (bfd *abfd, const char *name, flagword flags);
1155 Create a new empty section called @var{name} and attach it to the end of
1156 the chain of sections for @var{abfd}. Create a new section even if there
1157 is already a section with that name. Also set the attributes of the
1158 new section to the value @var{flags}.
1160 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
1161 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
1162 o <<bfd_error_no_memory>> - If memory allocation fails.
1166 bfd_make_section_anyway_with_flags (bfd
*abfd
, const char *name
,
1169 struct section_hash_entry
*sh
;
1172 if (abfd
->output_has_begun
)
1174 bfd_set_error (bfd_error_invalid_operation
);
1178 sh
= section_hash_lookup (&abfd
->section_htab
, name
, true, false);
1182 newsect
= &sh
->section
;
1183 if (newsect
->name
!= NULL
)
1185 /* We are making a section of the same name. Put it in the
1186 section hash table. Even though we can't find it directly by a
1187 hash lookup, we'll be able to find the section by traversing
1188 sh->root.next quicker than looking at all the bfd sections. */
1189 struct section_hash_entry
*new_sh
;
1190 new_sh
= (struct section_hash_entry
*)
1191 bfd_section_hash_newfunc (NULL
, &abfd
->section_htab
, name
);
1195 new_sh
->root
= sh
->root
;
1196 sh
->root
.next
= &new_sh
->root
;
1197 newsect
= &new_sh
->section
;
1200 newsect
->flags
= flags
;
1201 newsect
->name
= name
;
1202 return bfd_section_init (abfd
, newsect
);
1207 bfd_make_section_anyway
1210 asection *bfd_make_section_anyway (bfd *abfd, const char *name);
1213 Create a new empty section called @var{name} and attach it to the end of
1214 the chain of sections for @var{abfd}. Create a new section even if there
1215 is already a section with that name.
1217 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
1218 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
1219 o <<bfd_error_no_memory>> - If memory allocation fails.
1223 bfd_make_section_anyway (bfd
*abfd
, const char *name
)
1225 return bfd_make_section_anyway_with_flags (abfd
, name
, 0);
1230 bfd_make_section_with_flags
1233 asection *bfd_make_section_with_flags
1234 (bfd *, const char *name, flagword flags);
1237 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
1238 bfd_set_error ()) without changing the section chain if there is already a
1239 section named @var{name}. Also set the attributes of the new section to
1240 the value @var{flags}. If there is an error, return <<NULL>> and set
1245 bfd_make_section_with_flags (bfd
*abfd
, const char *name
,
1248 struct section_hash_entry
*sh
;
1251 if (abfd
== NULL
|| name
== NULL
|| abfd
->output_has_begun
)
1253 bfd_set_error (bfd_error_invalid_operation
);
1257 if (strcmp (name
, BFD_ABS_SECTION_NAME
) == 0
1258 || strcmp (name
, BFD_COM_SECTION_NAME
) == 0
1259 || strcmp (name
, BFD_UND_SECTION_NAME
) == 0
1260 || strcmp (name
, BFD_IND_SECTION_NAME
) == 0)
1263 sh
= section_hash_lookup (&abfd
->section_htab
, name
, true, false);
1267 newsect
= &sh
->section
;
1268 if (newsect
->name
!= NULL
)
1270 /* Section already exists. */
1274 newsect
->name
= name
;
1275 newsect
->flags
= flags
;
1276 return bfd_section_init (abfd
, newsect
);
1284 asection *bfd_make_section (bfd *, const char *name);
1287 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
1288 bfd_set_error ()) without changing the section chain if there is already a
1289 section named @var{name}. If there is an error, return <<NULL>> and set
1294 bfd_make_section (bfd
*abfd
, const char *name
)
1296 return bfd_make_section_with_flags (abfd
, name
, 0);
1301 bfd_set_section_flags
1304 bool bfd_set_section_flags (asection *sec, flagword flags);
1307 Set the attributes of the section @var{sec} to the value @var{flags}.
1308 Return <<TRUE>> on success, <<FALSE>> on error. Possible error
1311 o <<bfd_error_invalid_operation>> -
1312 The section cannot have one or more of the attributes
1313 requested. For example, a .bss section in <<a.out>> may not
1314 have the <<SEC_HAS_CONTENTS>> field set.
1319 bfd_set_section_flags (asection
*section
, flagword flags
)
1321 section
->flags
= flags
;
1330 void bfd_rename_section
1331 (asection *sec, const char *newname);
1334 Rename section @var{sec} to @var{newname}.
1338 bfd_rename_section (asection
*sec
, const char *newname
)
1340 struct section_hash_entry
*sh
;
1342 sh
= (struct section_hash_entry
*)
1343 ((char *) sec
- offsetof (struct section_hash_entry
, section
));
1344 sh
->section
.name
= newname
;
1345 bfd_hash_rename (&sec
->owner
->section_htab
, newname
, &sh
->root
);
1350 bfd_map_over_sections
1353 void bfd_map_over_sections
1355 void (*func) (bfd *abfd, asection *sect, void *obj),
1359 Call the provided function @var{func} for each section
1360 attached to the BFD @var{abfd}, passing @var{obj} as an
1361 argument. The function will be called as if by
1363 | func (abfd, the_section, obj);
1365 This is the preferred method for iterating over sections; an
1366 alternative would be to use a loop:
1369 | for (p = abfd->sections; p != NULL; p = p->next)
1370 | func (abfd, p, ...)
1375 bfd_map_over_sections (bfd
*abfd
,
1376 void (*operation
) (bfd
*, asection
*, void *),
1382 for (sect
= abfd
->sections
; sect
!= NULL
; i
++, sect
= sect
->next
)
1383 (*operation
) (abfd
, sect
, user_storage
);
1385 if (i
!= abfd
->section_count
) /* Debugging */
1391 bfd_sections_find_if
1394 asection *bfd_sections_find_if
1396 bool (*operation) (bfd *abfd, asection *sect, void *obj),
1400 Call the provided function @var{operation} for each section
1401 attached to the BFD @var{abfd}, passing @var{obj} as an
1402 argument. The function will be called as if by
1404 | operation (abfd, the_section, obj);
1406 It returns the first section for which @var{operation} returns true.
1411 bfd_sections_find_if (bfd
*abfd
,
1412 bool (*operation
) (bfd
*, asection
*, void *),
1417 for (sect
= abfd
->sections
; sect
!= NULL
; sect
= sect
->next
)
1418 if ((*operation
) (abfd
, sect
, user_storage
))
1426 bfd_set_section_size
1429 bool bfd_set_section_size (asection *sec, bfd_size_type val);
1432 Set @var{sec} to the size @var{val}. If the operation is
1433 ok, then <<TRUE>> is returned, else <<FALSE>>.
1435 Possible error returns:
1436 o <<bfd_error_invalid_operation>> -
1437 Writing has started to the BFD, so setting the size is invalid.
1442 bfd_set_section_size (asection
*sec
, bfd_size_type val
)
1444 /* Once you've started writing to any section you cannot create or change
1445 the size of any others. */
1447 if (sec
->owner
== NULL
|| sec
->owner
->output_has_begun
)
1449 bfd_set_error (bfd_error_invalid_operation
);
1459 bfd_set_section_contents
1462 bool bfd_set_section_contents
1463 (bfd *abfd, asection *section, const void *data,
1464 file_ptr offset, bfd_size_type count);
1467 Sets the contents of the section @var{section} in BFD
1468 @var{abfd} to the data starting in memory at @var{location}.
1469 The data is written to the output section starting at offset
1470 @var{offset} for @var{count} octets.
1472 Normally <<TRUE>> is returned, but <<FALSE>> is returned if
1473 there was an error. Possible error returns are:
1474 o <<bfd_error_no_contents>> -
1475 The output section does not have the <<SEC_HAS_CONTENTS>>
1476 attribute, so nothing can be written to it.
1477 o <<bfd_error_bad_value>> -
1478 The section is unable to contain all of the data.
1479 o <<bfd_error_invalid_operation>> -
1480 The BFD is not writeable.
1481 o and some more too.
1483 This routine is front end to the back end function
1484 <<_bfd_set_section_contents>>.
1489 bfd_set_section_contents (bfd
*abfd
,
1491 const void *location
,
1493 bfd_size_type count
)
1497 if (!(bfd_section_flags (section
) & SEC_HAS_CONTENTS
))
1499 bfd_set_error (bfd_error_no_contents
);
1504 if ((bfd_size_type
) offset
> sz
1505 || count
> sz
- offset
1506 || count
!= (size_t) count
)
1508 bfd_set_error (bfd_error_bad_value
);
1512 if (!bfd_write_p (abfd
))
1514 bfd_set_error (bfd_error_invalid_operation
);
1518 /* Record a copy of the data in memory if desired. */
1519 if (section
->contents
1520 && location
!= section
->contents
+ offset
)
1521 memcpy (section
->contents
+ offset
, location
, (size_t) count
);
1523 if (BFD_SEND (abfd
, _bfd_set_section_contents
,
1524 (abfd
, section
, location
, offset
, count
)))
1526 abfd
->output_has_begun
= true;
1535 bfd_get_section_contents
1538 bool bfd_get_section_contents
1539 (bfd *abfd, asection *section, void *location, file_ptr offset,
1540 bfd_size_type count);
1543 Read data from @var{section} in BFD @var{abfd}
1544 into memory starting at @var{location}. The data is read at an
1545 offset of @var{offset} from the start of the input section,
1546 and is read for @var{count} bytes.
1548 If the contents of a constructor with the <<SEC_CONSTRUCTOR>>
1549 flag set are requested or if the section does not have the
1550 <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled
1551 with zeroes. If no errors occur, <<TRUE>> is returned, else
1556 bfd_get_section_contents (bfd
*abfd
,
1560 bfd_size_type count
)
1564 if (section
->flags
& SEC_CONSTRUCTOR
)
1566 memset (location
, 0, (size_t) count
);
1570 if (abfd
->direction
!= write_direction
&& section
->rawsize
!= 0)
1571 sz
= section
->rawsize
;
1574 if ((bfd_size_type
) offset
> sz
1575 || count
> sz
- offset
1576 || count
!= (size_t) count
)
1578 bfd_set_error (bfd_error_bad_value
);
1586 if ((section
->flags
& SEC_HAS_CONTENTS
) == 0)
1588 memset (location
, 0, (size_t) count
);
1592 if ((section
->flags
& SEC_IN_MEMORY
) != 0)
1594 if (section
->contents
== NULL
)
1596 /* This can happen because of errors earlier on in the linking process.
1597 We do not want to seg-fault here, so clear the flag and return an
1599 section
->flags
&= ~ SEC_IN_MEMORY
;
1600 bfd_set_error (bfd_error_invalid_operation
);
1604 memmove (location
, section
->contents
+ offset
, (size_t) count
);
1608 return BFD_SEND (abfd
, _bfd_get_section_contents
,
1609 (abfd
, section
, location
, offset
, count
));
1614 bfd_malloc_and_get_section
1617 bool bfd_malloc_and_get_section
1618 (bfd *abfd, asection *section, bfd_byte **buf);
1621 Read all data from @var{section} in BFD @var{abfd}
1622 into a buffer, *@var{buf}, malloc'd by this function.
1626 bfd_malloc_and_get_section (bfd
*abfd
, sec_ptr sec
, bfd_byte
**buf
)
1629 return bfd_get_full_section_contents (abfd
, sec
, buf
);
1633 bfd_copy_private_section_data
1636 bool bfd_copy_private_section_data
1637 (bfd *ibfd, asection *isec, bfd *obfd, asection *osec);
1640 Copy private section information from @var{isec} in the BFD
1641 @var{ibfd} to the section @var{osec} in the BFD @var{obfd}.
1642 Return <<TRUE>> on success, <<FALSE>> on error. Possible error
1645 o <<bfd_error_no_memory>> -
1646 Not enough memory exists to create private data for @var{osec}.
1648 .#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \
1649 . BFD_SEND (obfd, _bfd_copy_private_section_data, \
1650 . (ibfd, isection, obfd, osection))
1655 bfd_generic_is_group_section
1658 bool bfd_generic_is_group_section (bfd *, const asection *sec);
1661 Returns TRUE if @var{sec} is a member of a group.
1665 bfd_generic_is_group_section (bfd
*abfd ATTRIBUTE_UNUSED
,
1666 const asection
*sec ATTRIBUTE_UNUSED
)
1673 bfd_generic_group_name
1676 const char *bfd_generic_group_name (bfd *, const asection *sec);
1679 Returns group name if @var{sec} is a member of a group.
1683 bfd_generic_group_name (bfd
*abfd ATTRIBUTE_UNUSED
,
1684 const asection
*sec ATTRIBUTE_UNUSED
)
1691 bfd_generic_discard_group
1694 bool bfd_generic_discard_group (bfd *abfd, asection *group);
1697 Remove all members of @var{group} from the output.
1701 bfd_generic_discard_group (bfd
*abfd ATTRIBUTE_UNUSED
,
1702 asection
*group ATTRIBUTE_UNUSED
)
1708 _bfd_nowrite_set_section_contents (bfd
*abfd
,
1709 sec_ptr section ATTRIBUTE_UNUSED
,
1710 const void *location ATTRIBUTE_UNUSED
,
1711 file_ptr offset ATTRIBUTE_UNUSED
,
1712 bfd_size_type count ATTRIBUTE_UNUSED
)
1714 return _bfd_bool_bfd_false_error (abfd
);