1 /* Object file "section" support for the BFD library.
2 Copyright (C) 1990-2023 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 . {* The next section in the list belonging to the BFD, or NULL. *}
155 . struct bfd_section *next;
157 . {* The previous section in the list belonging to the BFD, or NULL. *}
158 . struct bfd_section *prev;
160 . {* A unique sequence number. *}
163 . {* A unique section number which can be used by assembler to
164 . distinguish different sections with the same section name. *}
165 . unsigned int section_id;
167 . {* Which section in the bfd; 0..n-1 as sections are created in a bfd. *}
168 . unsigned int index;
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 . {* Indicate that section has the purecode flag set. *}
340 .#define SEC_ELF_PURECODE 0x8000000
342 . {* When a section with this flag is being linked, then if the size of
343 . the input section is less than a page, it should not cross a page
344 . boundary. If the size of the input section is one page or more,
345 . it should be aligned on a page boundary. This is for TI
346 . TMS320C54X only. *}
347 .#define SEC_TIC54X_BLOCK 0x10000000
349 . {* Conditionally link this section; do not link if there are no
350 . references found to any symbol in the section. This is for TI
351 . TMS320C54X only. *}
352 .#define SEC_TIC54X_CLINK 0x20000000
354 . {* This section contains vliw code. This is for Toshiba MeP only. *}
355 .#define SEC_MEP_VLIW 0x20000000
357 . {* All symbols, sizes and relocations in this section are octets
358 . instead of bytes. Required for DWARF debug sections as DWARF
359 . information is organized in octets, not bytes. *}
360 .#define SEC_ELF_OCTETS 0x40000000
362 . {* Indicate that section has the no read flag set. This happens
363 . when memory read flag isn't set. *}
364 .#define SEC_COFF_NOREAD 0x40000000
366 . {* End of section flags. *}
368 . {* Some internal packed boolean fields. *}
370 . {* See the vma field. *}
371 . unsigned int user_set_vma : 1;
373 . {* A mark flag used by some of the linker backends. *}
374 . unsigned int linker_mark : 1;
376 . {* Another mark flag used by some of the linker backends. Set for
377 . output sections that have an input section. *}
378 . unsigned int linker_has_input : 1;
380 . {* Mark flag used by some linker backends for garbage collection. *}
381 . unsigned int gc_mark : 1;
383 . {* Section compression status. *}
384 . unsigned int compress_status : 2;
385 .#define COMPRESS_SECTION_NONE 0
386 .#define COMPRESS_SECTION_DONE 1
387 .#define DECOMPRESS_SECTION_ZLIB 2
388 .#define DECOMPRESS_SECTION_ZSTD 3
390 . {* The following flags are used by the ELF linker. *}
392 . {* Mark sections which have been allocated to segments. *}
393 . unsigned int segment_mark : 1;
395 . {* Type of sec_info information. *}
396 . unsigned int sec_info_type:3;
397 .#define SEC_INFO_TYPE_NONE 0
398 .#define SEC_INFO_TYPE_STABS 1
399 .#define SEC_INFO_TYPE_MERGE 2
400 .#define SEC_INFO_TYPE_EH_FRAME 3
401 .#define SEC_INFO_TYPE_JUST_SYMS 4
402 .#define SEC_INFO_TYPE_TARGET 5
403 .#define SEC_INFO_TYPE_EH_FRAME_ENTRY 6
404 .#define SEC_INFO_TYPE_SFRAME 7
406 . {* Nonzero if this section uses RELA relocations, rather than REL. *}
407 . unsigned int use_rela_p:1;
409 . {* Bits used by various backends. The generic code doesn't touch
412 . unsigned int sec_flg0:1;
413 . unsigned int sec_flg1:1;
414 . unsigned int sec_flg2:1;
415 . unsigned int sec_flg3:1;
416 . unsigned int sec_flg4:1;
417 . unsigned int sec_flg5:1;
419 . {* End of internal packed boolean fields. *}
421 . {* The virtual memory address of the section - where it will be
422 . at run time. The symbols are relocated against this. The
423 . user_set_vma flag is maintained by bfd; if it's not set, the
424 . backend can assign addresses (for example, in <<a.out>>, where
425 . the default address for <<.data>> is dependent on the specific
426 . target and various flags). *}
429 . {* The load address of the section - where it would be in a
430 . rom image; really only used for writing section header
434 . {* The size of the section in *octets*, as it will be output.
435 . Contains a value even if the section has no contents (e.g., the
436 . size of <<.bss>>). *}
437 . bfd_size_type size;
439 . {* For input sections, the original size on disk of the section, in
440 . octets. This field should be set for any section whose size is
441 . changed by linker relaxation. It is required for sections where
442 . the linker relaxation scheme doesn't cache altered section and
443 . reloc contents (stabs, eh_frame, SEC_MERGE, some coff relaxing
444 . targets), and thus the original size needs to be kept to read the
445 . section multiple times. For output sections, rawsize holds the
446 . section size calculated on a previous linker relaxation pass. *}
447 . bfd_size_type rawsize;
449 . {* The compressed size of the section in octets. *}
450 . bfd_size_type compressed_size;
452 . {* If this section is going to be output, then this value is the
453 . offset in *bytes* into the output section of the first byte in the
454 . input section (byte ==> smallest addressable unit on the
455 . target). In most cases, if this was going to start at the
456 . 100th octet (8-bit quantity) in the output section, this value
457 . would be 100. However, if the target byte size is 16 bits
458 . (bfd_octets_per_byte is "2"), this value would be 50. *}
459 . bfd_vma output_offset;
461 . {* The output section through which to map on output. *}
462 . struct bfd_section *output_section;
464 . {* If an input section, a pointer to a vector of relocation
465 . records for the data in this section. *}
466 . struct reloc_cache_entry *relocation;
468 . {* If an output section, a pointer to a vector of pointers to
469 . relocation records for the data in this section. *}
470 . struct reloc_cache_entry **orelocation;
472 . {* The number of relocation records in one of the above. *}
473 . unsigned reloc_count;
475 . {* The alignment requirement of the section, as an exponent of 2 -
476 . e.g., 3 aligns to 2^3 (or 8). *}
477 . unsigned int alignment_power;
479 . {* Information below is back end specific - and not always used
482 . {* File position of section data. *}
485 . {* File position of relocation info. *}
486 . file_ptr rel_filepos;
488 . {* File position of line data. *}
489 . file_ptr line_filepos;
491 . {* Pointer to data for applications. *}
494 . {* If the SEC_IN_MEMORY flag is set, this points to the actual
496 . unsigned char *contents;
498 . {* Attached line number information. *}
501 . {* Number of line number records. *}
502 . unsigned int lineno_count;
504 . {* Entity size for merging purposes. *}
505 . unsigned int entsize;
507 . {* Points to the kept section if this section is a link-once section,
508 . and is discarded. *}
509 . struct bfd_section *kept_section;
511 . {* When a section is being output, this value changes as more
512 . linenumbers are written out. *}
513 . file_ptr moving_line_filepos;
515 . {* What the section number is in the target world. *}
520 . {* If this is a constructor section then here is a list of the
521 . relocations created to relocate items within it. *}
522 . struct relent_chain *constructor_chain;
524 . {* The BFD which owns the section. *}
527 . {* A symbol which points at this section only. *}
528 . struct bfd_symbol *symbol;
529 . struct bfd_symbol **symbol_ptr_ptr;
531 . {* Early in the link process, map_head and map_tail are used to build
532 . a list of input sections attached to an output section. Later,
533 . output sections use these fields for a list of bfd_link_order
534 . structs. The linked_to_symbol_name field is for ELF assembler
537 . struct bfd_link_order *link_order;
538 . struct bfd_section *s;
539 . const char *linked_to_symbol_name;
540 . } map_head, map_tail;
542 . {* Points to the output section this section is already assigned to,
543 . if any. This is used when support for non-contiguous memory
544 . regions is enabled. *}
545 . struct bfd_section *already_assigned;
547 . {* Explicitly specified section type, if non-zero. *}
552 .static inline const char *
553 .bfd_section_name (const asection *sec)
558 .static inline bfd_size_type
559 .bfd_section_size (const asection *sec)
564 .static inline bfd_vma
565 .bfd_section_vma (const asection *sec)
570 .static inline bfd_vma
571 .bfd_section_lma (const asection *sec)
576 .static inline unsigned int
577 .bfd_section_alignment (const asection *sec)
579 . return sec->alignment_power;
582 .static inline flagword
583 .bfd_section_flags (const asection *sec)
588 .static inline void *
589 .bfd_section_userdata (const asection *sec)
591 . return sec->userdata;
594 .bfd_is_com_section (const asection *sec)
596 . return (sec->flags & SEC_IS_COMMON) != 0;
599 .{* Note: the following are provided as inline functions rather than macros
600 . because not all callers use the return value. A macro implementation
601 . would use a comma expression, eg: "((ptr)->foo = val, TRUE)" and some
602 . compilers will complain about comma expressions that have no effect. *}
604 .bfd_set_section_userdata (asection *sec, void *val)
606 . sec->userdata = val;
611 .bfd_set_section_vma (asection *sec, bfd_vma val)
613 . sec->vma = sec->lma = val;
614 . sec->user_set_vma = true;
619 .bfd_set_section_lma (asection *sec, bfd_vma val)
626 .bfd_set_section_alignment (asection *sec, unsigned int val)
628 . if (val >= sizeof (bfd_vma) * 8 - 1)
630 . sec->alignment_power = val;
634 .{* These sections are global, and are managed by BFD. The application
635 . and target back end are not permitted to change the values in
637 .extern asection _bfd_std_section[4];
639 .#define BFD_ABS_SECTION_NAME "*ABS*"
640 .#define BFD_UND_SECTION_NAME "*UND*"
641 .#define BFD_COM_SECTION_NAME "*COM*"
642 .#define BFD_IND_SECTION_NAME "*IND*"
644 .{* Pointer to the common section. *}
645 .#define bfd_com_section_ptr (&_bfd_std_section[0])
646 .{* Pointer to the undefined section. *}
647 .#define bfd_und_section_ptr (&_bfd_std_section[1])
648 .{* Pointer to the absolute section. *}
649 .#define bfd_abs_section_ptr (&_bfd_std_section[2])
650 .{* Pointer to the indirect section. *}
651 .#define bfd_ind_section_ptr (&_bfd_std_section[3])
654 .bfd_is_und_section (const asection *sec)
656 . return sec == bfd_und_section_ptr;
660 .bfd_is_abs_section (const asection *sec)
662 . return sec == bfd_abs_section_ptr;
666 .bfd_is_ind_section (const asection *sec)
668 . return sec == bfd_ind_section_ptr;
672 .bfd_is_const_section (const asection *sec)
674 . return (sec >= _bfd_std_section
675 . && sec < _bfd_std_section + (sizeof (_bfd_std_section)
676 . / sizeof (_bfd_std_section[0])));
679 .{* Return TRUE if input section SEC has been discarded. *}
681 .discarded_section (const asection *sec)
683 . return (!bfd_is_abs_section (sec)
684 . && bfd_is_abs_section (sec->output_section)
685 . && sec->sec_info_type != SEC_INFO_TYPE_MERGE
686 . && sec->sec_info_type != SEC_INFO_TYPE_JUST_SYMS);
689 .#define BFD_FAKE_SECTION(SEC, SYM, NAME, IDX, FLAGS) \
690 . {* name, next, prev, id, section_id, index, flags, user_set_vma, *} \
691 . { NAME, NULL, NULL, IDX, 0, 0, FLAGS, 0, \
693 . {* linker_mark, linker_has_input, gc_mark, decompress_status, *} \
696 . {* segment_mark, sec_info_type, use_rela_p, *} \
699 . {* sec_flg0, sec_flg1, sec_flg2, sec_flg3, sec_flg4, sec_flg5, *} \
700 . 0, 0, 0, 0, 0, 0, \
702 . {* vma, lma, size, rawsize, compressed_size, *} \
705 . {* output_offset, output_section, relocation, orelocation, *} \
706 . 0, &SEC, NULL, NULL, \
708 . {* reloc_count, alignment_power, filepos, rel_filepos, *} \
711 . {* line_filepos, userdata, contents, lineno, lineno_count, *} \
712 . 0, NULL, NULL, NULL, 0, \
714 . {* entsize, kept_section, moving_line_filepos, *} \
717 . {* target_index, used_by_bfd, constructor_chain, owner, *} \
718 . 0, NULL, NULL, NULL, \
720 . {* symbol, symbol_ptr_ptr, *} \
721 . (struct bfd_symbol *) SYM, &SEC.symbol, \
723 . {* map_head, map_tail, already_assigned, type *} \
724 . { NULL }, { NULL }, NULL, 0 \
728 .{* We use a macro to initialize the static asymbol structures because
729 . traditional C does not permit us to initialize a union member while
730 . gcc warns if we don't initialize it.
731 . the_bfd, name, value, attr, section [, udata] *}
733 .#define GLOBAL_SYM_INIT(NAME, SECTION) \
734 . { 0, NAME, 0, BSF_SECTION_SYM, SECTION, { 0 }}
736 .#define GLOBAL_SYM_INIT(NAME, SECTION) \
737 . { 0, NAME, 0, BSF_SECTION_SYM, SECTION }
742 /* These symbols are global, not specific to any BFD. Therefore, anything
743 that tries to change them is broken, and should be repaired. */
745 static const asymbol global_syms
[] =
747 GLOBAL_SYM_INIT (BFD_COM_SECTION_NAME
, bfd_com_section_ptr
),
748 GLOBAL_SYM_INIT (BFD_UND_SECTION_NAME
, bfd_und_section_ptr
),
749 GLOBAL_SYM_INIT (BFD_ABS_SECTION_NAME
, bfd_abs_section_ptr
),
750 GLOBAL_SYM_INIT (BFD_IND_SECTION_NAME
, bfd_ind_section_ptr
)
753 #define STD_SECTION(NAME, IDX, FLAGS) \
754 BFD_FAKE_SECTION(_bfd_std_section[IDX], &global_syms[IDX], NAME, IDX, FLAGS)
756 asection _bfd_std_section
[] = {
757 STD_SECTION (BFD_COM_SECTION_NAME
, 0, SEC_IS_COMMON
),
758 STD_SECTION (BFD_UND_SECTION_NAME
, 1, 0),
759 STD_SECTION (BFD_ABS_SECTION_NAME
, 2, 0),
760 STD_SECTION (BFD_IND_SECTION_NAME
, 3, 0)
764 /* Initialize an entry in the section hash table. */
766 struct bfd_hash_entry
*
767 bfd_section_hash_newfunc (struct bfd_hash_entry
*entry
,
768 struct bfd_hash_table
*table
,
771 /* Allocate the structure if it has not already been allocated by a
775 entry
= (struct bfd_hash_entry
*)
776 bfd_hash_allocate (table
, sizeof (struct section_hash_entry
));
781 /* Call the allocation method of the superclass. */
782 entry
= bfd_hash_newfunc (entry
, table
, string
);
784 memset (&((struct section_hash_entry
*) entry
)->section
, 0,
790 #define section_hash_lookup(table, string, create, copy) \
791 ((struct section_hash_entry *) \
792 bfd_hash_lookup ((table), (string), (create), (copy)))
794 /* Create a symbol whose only job is to point to this section. This
795 is useful for things like relocs which are relative to the base
799 _bfd_generic_new_section_hook (bfd
*abfd
, asection
*newsect
)
801 newsect
->symbol
= bfd_make_empty_symbol (abfd
);
802 if (newsect
->symbol
== NULL
)
805 newsect
->symbol
->name
= newsect
->name
;
806 newsect
->symbol
->value
= 0;
807 newsect
->symbol
->section
= newsect
;
808 newsect
->symbol
->flags
= BSF_SECTION_SYM
;
810 newsect
->symbol_ptr_ptr
= &newsect
->symbol
;
814 unsigned int _bfd_section_id
= 0x10; /* id 0 to 3 used by STD_SECTION. */
816 /* Initializes a new section. NEWSECT->NAME is already set. */
819 bfd_section_init (bfd
*abfd
, asection
*newsect
)
821 newsect
->id
= _bfd_section_id
;
822 newsect
->index
= abfd
->section_count
;
823 newsect
->owner
= abfd
;
825 if (! BFD_SEND (abfd
, _new_section_hook
, (abfd
, newsect
)))
829 abfd
->section_count
++;
830 bfd_section_list_append (abfd
, newsect
);
837 section prototypes, , typedef asection, Sections
841 These are the functions exported by the section handling part of BFD.
846 bfd_section_list_clear
849 void bfd_section_list_clear (bfd *);
852 Clears the section list, and also resets the section count and
857 bfd_section_list_clear (bfd
*abfd
)
859 abfd
->sections
= NULL
;
860 abfd
->section_last
= NULL
;
861 abfd
->section_count
= 0;
862 memset (abfd
->section_htab
.table
, 0,
863 abfd
->section_htab
.size
* sizeof (struct bfd_hash_entry
*));
864 abfd
->section_htab
.count
= 0;
869 bfd_get_section_by_name
872 asection *bfd_get_section_by_name (bfd *abfd, const char *name);
875 Return the most recently created section attached to @var{abfd}
876 named @var{name}. Return NULL if no such section exists.
880 bfd_get_section_by_name (bfd
*abfd
, const char *name
)
882 struct section_hash_entry
*sh
;
887 sh
= section_hash_lookup (&abfd
->section_htab
, name
, false, false);
896 bfd_get_next_section_by_name
899 asection *bfd_get_next_section_by_name (bfd *ibfd, asection *sec);
902 Given @var{sec} is a section returned by @code{bfd_get_section_by_name},
903 return the next most recently created section attached to the same
904 BFD with the same name, or if no such section exists in the same BFD and
905 IBFD is non-NULL, the next section with the same name in any input
906 BFD following IBFD. Return NULL on finding no section.
910 bfd_get_next_section_by_name (bfd
*ibfd
, asection
*sec
)
912 struct section_hash_entry
*sh
;
916 sh
= ((struct section_hash_entry
*)
917 ((char *) sec
- offsetof (struct section_hash_entry
, section
)));
919 hash
= sh
->root
.hash
;
921 for (sh
= (struct section_hash_entry
*) sh
->root
.next
;
923 sh
= (struct section_hash_entry
*) sh
->root
.next
)
924 if (sh
->root
.hash
== hash
925 && strcmp (sh
->root
.string
, name
) == 0)
930 while ((ibfd
= ibfd
->link
.next
) != NULL
)
932 asection
*s
= bfd_get_section_by_name (ibfd
, name
);
943 bfd_get_linker_section
946 asection *bfd_get_linker_section (bfd *abfd, const char *name);
949 Return the linker created section attached to @var{abfd}
950 named @var{name}. Return NULL if no such section exists.
954 bfd_get_linker_section (bfd
*abfd
, const char *name
)
956 asection
*sec
= bfd_get_section_by_name (abfd
, name
);
958 while (sec
!= NULL
&& (sec
->flags
& SEC_LINKER_CREATED
) == 0)
959 sec
= bfd_get_next_section_by_name (NULL
, sec
);
965 bfd_get_section_by_name_if
968 asection *bfd_get_section_by_name_if
971 bool (*func) (bfd *abfd, asection *sect, void *obj),
975 Call the provided function @var{func} for each section
976 attached to the BFD @var{abfd} whose name matches @var{name},
977 passing @var{obj} as an argument. The function will be called
980 | func (abfd, the_section, obj);
982 It returns the first section for which @var{func} returns true,
988 bfd_get_section_by_name_if (bfd
*abfd
, const char *name
,
989 bool (*operation
) (bfd
*, asection
*, void *),
992 struct section_hash_entry
*sh
;
998 sh
= section_hash_lookup (&abfd
->section_htab
, name
, false, false);
1002 hash
= sh
->root
.hash
;
1003 for (; sh
!= NULL
; sh
= (struct section_hash_entry
*) sh
->root
.next
)
1004 if (sh
->root
.hash
== hash
1005 && strcmp (sh
->root
.string
, name
) == 0
1006 && (*operation
) (abfd
, &sh
->section
, user_storage
))
1007 return &sh
->section
;
1014 bfd_get_unique_section_name
1017 char *bfd_get_unique_section_name
1018 (bfd *abfd, const char *templat, int *count);
1021 Invent a section name that is unique in @var{abfd} by tacking
1022 a dot and a digit suffix onto the original @var{templat}. If
1023 @var{count} is non-NULL, then it specifies the first number
1024 tried as a suffix to generate a unique name. The value
1025 pointed to by @var{count} will be incremented in this case.
1029 bfd_get_unique_section_name (bfd
*abfd
, const char *templat
, int *count
)
1035 len
= strlen (templat
);
1036 sname
= (char *) bfd_malloc (len
+ 8);
1039 memcpy (sname
, templat
, len
);
1046 /* If we have a million sections, something is badly wrong. */
1049 sprintf (sname
+ len
, ".%d", num
++);
1051 while (section_hash_lookup (&abfd
->section_htab
, sname
, false, false));
1060 bfd_make_section_old_way
1063 asection *bfd_make_section_old_way (bfd *abfd, const char *name);
1066 Create a new empty section called @var{name}
1067 and attach it to the end of the chain of sections for the
1068 BFD @var{abfd}. An attempt to create a section with a name which
1069 is already in use returns its pointer without changing the
1072 It has the funny name since this is the way it used to be
1073 before it was rewritten....
1075 Possible errors are:
1076 o <<bfd_error_invalid_operation>> -
1077 If output has already started for this BFD.
1078 o <<bfd_error_no_memory>> -
1079 If memory allocation fails.
1084 bfd_make_section_old_way (bfd
*abfd
, const char *name
)
1088 if (abfd
->output_has_begun
)
1090 bfd_set_error (bfd_error_invalid_operation
);
1094 if (strcmp (name
, BFD_ABS_SECTION_NAME
) == 0)
1095 newsect
= bfd_abs_section_ptr
;
1096 else if (strcmp (name
, BFD_COM_SECTION_NAME
) == 0)
1097 newsect
= bfd_com_section_ptr
;
1098 else if (strcmp (name
, BFD_UND_SECTION_NAME
) == 0)
1099 newsect
= bfd_und_section_ptr
;
1100 else if (strcmp (name
, BFD_IND_SECTION_NAME
) == 0)
1101 newsect
= bfd_ind_section_ptr
;
1104 struct section_hash_entry
*sh
;
1106 sh
= section_hash_lookup (&abfd
->section_htab
, name
, true, false);
1110 newsect
= &sh
->section
;
1111 if (newsect
->name
!= NULL
)
1113 /* Section already exists. */
1117 newsect
->name
= name
;
1118 return bfd_section_init (abfd
, newsect
);
1121 /* Call new_section_hook when "creating" the standard abs, com, und
1122 and ind sections to tack on format specific section data.
1123 Also, create a proper section symbol. */
1124 if (! BFD_SEND (abfd
, _new_section_hook
, (abfd
, newsect
)))
1131 bfd_make_section_anyway_with_flags
1134 asection *bfd_make_section_anyway_with_flags
1135 (bfd *abfd, const char *name, flagword flags);
1138 Create a new empty section called @var{name} and attach it to the end of
1139 the chain of sections for @var{abfd}. Create a new section even if there
1140 is already a section with that name. Also set the attributes of the
1141 new section to the value @var{flags}.
1143 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
1144 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
1145 o <<bfd_error_no_memory>> - If memory allocation fails.
1149 bfd_make_section_anyway_with_flags (bfd
*abfd
, const char *name
,
1152 struct section_hash_entry
*sh
;
1155 if (abfd
->output_has_begun
)
1157 bfd_set_error (bfd_error_invalid_operation
);
1161 sh
= section_hash_lookup (&abfd
->section_htab
, name
, true, false);
1165 newsect
= &sh
->section
;
1166 if (newsect
->name
!= NULL
)
1168 /* We are making a section of the same name. Put it in the
1169 section hash table. Even though we can't find it directly by a
1170 hash lookup, we'll be able to find the section by traversing
1171 sh->root.next quicker than looking at all the bfd sections. */
1172 struct section_hash_entry
*new_sh
;
1173 new_sh
= (struct section_hash_entry
*)
1174 bfd_section_hash_newfunc (NULL
, &abfd
->section_htab
, name
);
1178 new_sh
->root
= sh
->root
;
1179 sh
->root
.next
= &new_sh
->root
;
1180 newsect
= &new_sh
->section
;
1183 newsect
->flags
= flags
;
1184 newsect
->name
= name
;
1185 return bfd_section_init (abfd
, newsect
);
1190 bfd_make_section_anyway
1193 asection *bfd_make_section_anyway (bfd *abfd, const char *name);
1196 Create a new empty section called @var{name} and attach it to the end of
1197 the chain of sections for @var{abfd}. Create a new section even if there
1198 is already a section with that name.
1200 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
1201 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
1202 o <<bfd_error_no_memory>> - If memory allocation fails.
1206 bfd_make_section_anyway (bfd
*abfd
, const char *name
)
1208 return bfd_make_section_anyway_with_flags (abfd
, name
, 0);
1213 bfd_make_section_with_flags
1216 asection *bfd_make_section_with_flags
1217 (bfd *, const char *name, flagword flags);
1220 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
1221 bfd_set_error ()) without changing the section chain if there is already a
1222 section named @var{name}. Also set the attributes of the new section to
1223 the value @var{flags}. If there is an error, return <<NULL>> and set
1228 bfd_make_section_with_flags (bfd
*abfd
, const char *name
,
1231 struct section_hash_entry
*sh
;
1234 if (abfd
== NULL
|| name
== NULL
|| abfd
->output_has_begun
)
1236 bfd_set_error (bfd_error_invalid_operation
);
1240 if (strcmp (name
, BFD_ABS_SECTION_NAME
) == 0
1241 || strcmp (name
, BFD_COM_SECTION_NAME
) == 0
1242 || strcmp (name
, BFD_UND_SECTION_NAME
) == 0
1243 || strcmp (name
, BFD_IND_SECTION_NAME
) == 0)
1246 sh
= section_hash_lookup (&abfd
->section_htab
, name
, true, false);
1250 newsect
= &sh
->section
;
1251 if (newsect
->name
!= NULL
)
1253 /* Section already exists. */
1257 newsect
->name
= name
;
1258 newsect
->flags
= flags
;
1259 return bfd_section_init (abfd
, newsect
);
1267 asection *bfd_make_section (bfd *, const char *name);
1270 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
1271 bfd_set_error ()) without changing the section chain if there is already a
1272 section named @var{name}. If there is an error, return <<NULL>> and set
1277 bfd_make_section (bfd
*abfd
, const char *name
)
1279 return bfd_make_section_with_flags (abfd
, name
, 0);
1284 bfd_set_section_flags
1287 bool bfd_set_section_flags (asection *sec, flagword flags);
1290 Set the attributes of the section @var{sec} to the value @var{flags}.
1291 Return <<TRUE>> on success, <<FALSE>> on error. Possible error
1294 o <<bfd_error_invalid_operation>> -
1295 The section cannot have one or more of the attributes
1296 requested. For example, a .bss section in <<a.out>> may not
1297 have the <<SEC_HAS_CONTENTS>> field set.
1302 bfd_set_section_flags (asection
*section
, flagword flags
)
1304 section
->flags
= flags
;
1313 void bfd_rename_section
1314 (asection *sec, const char *newname);
1317 Rename section @var{sec} to @var{newname}.
1321 bfd_rename_section (asection
*sec
, const char *newname
)
1323 struct section_hash_entry
*sh
;
1325 sh
= (struct section_hash_entry
*)
1326 ((char *) sec
- offsetof (struct section_hash_entry
, section
));
1327 sh
->section
.name
= newname
;
1328 bfd_hash_rename (&sec
->owner
->section_htab
, newname
, &sh
->root
);
1333 bfd_map_over_sections
1336 void bfd_map_over_sections
1338 void (*func) (bfd *abfd, asection *sect, void *obj),
1342 Call the provided function @var{func} for each section
1343 attached to the BFD @var{abfd}, passing @var{obj} as an
1344 argument. The function will be called as if by
1346 | func (abfd, the_section, obj);
1348 This is the preferred method for iterating over sections; an
1349 alternative would be to use a loop:
1352 | for (p = abfd->sections; p != NULL; p = p->next)
1353 | func (abfd, p, ...)
1358 bfd_map_over_sections (bfd
*abfd
,
1359 void (*operation
) (bfd
*, asection
*, void *),
1365 for (sect
= abfd
->sections
; sect
!= NULL
; i
++, sect
= sect
->next
)
1366 (*operation
) (abfd
, sect
, user_storage
);
1368 if (i
!= abfd
->section_count
) /* Debugging */
1374 bfd_sections_find_if
1377 asection *bfd_sections_find_if
1379 bool (*operation) (bfd *abfd, asection *sect, void *obj),
1383 Call the provided function @var{operation} for each section
1384 attached to the BFD @var{abfd}, passing @var{obj} as an
1385 argument. The function will be called as if by
1387 | operation (abfd, the_section, obj);
1389 It returns the first section for which @var{operation} returns true.
1394 bfd_sections_find_if (bfd
*abfd
,
1395 bool (*operation
) (bfd
*, asection
*, void *),
1400 for (sect
= abfd
->sections
; sect
!= NULL
; sect
= sect
->next
)
1401 if ((*operation
) (abfd
, sect
, user_storage
))
1409 bfd_set_section_size
1412 bool bfd_set_section_size (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 (asection
*sec
, 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 (sec
->owner
== NULL
|| sec
->owner
->output_has_begun
)
1432 bfd_set_error (bfd_error_invalid_operation
);
1442 bfd_set_section_contents
1445 bool 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{location}.
1452 The data is written to the output section starting at offset
1453 @var{offset} for @var{count} octets.
1455 Normally <<TRUE>> is returned, but <<FALSE>> is returned if
1456 there was an error. Possible error returns are:
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.
1460 o <<bfd_error_bad_value>> -
1461 The section is unable to contain all of the data.
1462 o <<bfd_error_invalid_operation>> -
1463 The BFD is not writeable.
1464 o and some more too.
1466 This routine is front end to the back end function
1467 <<_bfd_set_section_contents>>.
1472 bfd_set_section_contents (bfd
*abfd
,
1474 const void *location
,
1476 bfd_size_type count
)
1480 if (!(bfd_section_flags (section
) & SEC_HAS_CONTENTS
))
1482 bfd_set_error (bfd_error_no_contents
);
1487 if ((bfd_size_type
) offset
> sz
1488 || count
> sz
- offset
1489 || count
!= (size_t) count
)
1491 bfd_set_error (bfd_error_bad_value
);
1495 if (!bfd_write_p (abfd
))
1497 bfd_set_error (bfd_error_invalid_operation
);
1501 /* Record a copy of the data in memory if desired. */
1502 if (section
->contents
1503 && location
!= section
->contents
+ offset
)
1504 memcpy (section
->contents
+ offset
, location
, (size_t) count
);
1506 if (BFD_SEND (abfd
, _bfd_set_section_contents
,
1507 (abfd
, section
, location
, offset
, count
)))
1509 abfd
->output_has_begun
= true;
1518 bfd_get_section_contents
1521 bool bfd_get_section_contents
1522 (bfd *abfd, asection *section, void *location, file_ptr offset,
1523 bfd_size_type count);
1526 Read data from @var{section} in BFD @var{abfd}
1527 into memory starting at @var{location}. The data is read at an
1528 offset of @var{offset} from the start of the input section,
1529 and is read for @var{count} bytes.
1531 If the contents of a constructor with the <<SEC_CONSTRUCTOR>>
1532 flag set are requested or if the section does not have the
1533 <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled
1534 with zeroes. If no errors occur, <<TRUE>> is returned, else
1539 bfd_get_section_contents (bfd
*abfd
,
1543 bfd_size_type count
)
1547 if (section
->flags
& SEC_CONSTRUCTOR
)
1549 memset (location
, 0, (size_t) count
);
1553 sz
= bfd_get_section_limit_octets (abfd
, section
);
1554 if ((bfd_size_type
) offset
> sz
1555 || count
> sz
- offset
1556 || count
!= (size_t) count
)
1558 bfd_set_error (bfd_error_bad_value
);
1566 if ((section
->flags
& SEC_HAS_CONTENTS
) == 0)
1568 memset (location
, 0, (size_t) count
);
1572 if ((section
->flags
& SEC_IN_MEMORY
) != 0)
1574 if (section
->contents
== NULL
)
1576 /* This can happen because of errors earlier on in the linking process.
1577 We do not want to seg-fault here, so clear the flag and return an
1579 section
->flags
&= ~ SEC_IN_MEMORY
;
1580 bfd_set_error (bfd_error_invalid_operation
);
1584 memmove (location
, section
->contents
+ offset
, (size_t) count
);
1588 return BFD_SEND (abfd
, _bfd_get_section_contents
,
1589 (abfd
, section
, location
, offset
, count
));
1594 bfd_malloc_and_get_section
1597 bool bfd_malloc_and_get_section
1598 (bfd *abfd, asection *section, bfd_byte **buf);
1601 Read all data from @var{section} in BFD @var{abfd}
1602 into a buffer, *@var{buf}, malloc'd by this function.
1606 bfd_malloc_and_get_section (bfd
*abfd
, sec_ptr sec
, bfd_byte
**buf
)
1609 return bfd_get_full_section_contents (abfd
, sec
, buf
);
1613 bfd_copy_private_section_data
1616 bool bfd_copy_private_section_data
1617 (bfd *ibfd, asection *isec, bfd *obfd, asection *osec);
1620 Copy private section information from @var{isec} in the BFD
1621 @var{ibfd} to the section @var{osec} in the BFD @var{obfd}.
1622 Return <<TRUE>> on success, <<FALSE>> on error. Possible error
1625 o <<bfd_error_no_memory>> -
1626 Not enough memory exists to create private data for @var{osec}.
1628 .#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \
1629 . BFD_SEND (obfd, _bfd_copy_private_section_data, \
1630 . (ibfd, isection, obfd, osection))
1635 bfd_generic_is_group_section
1638 bool bfd_generic_is_group_section (bfd *, const asection *sec);
1641 Returns TRUE if @var{sec} is a member of a group.
1645 bfd_generic_is_group_section (bfd
*abfd ATTRIBUTE_UNUSED
,
1646 const asection
*sec ATTRIBUTE_UNUSED
)
1653 bfd_generic_group_name
1656 const char *bfd_generic_group_name (bfd *, const asection *sec);
1659 Returns group name if @var{sec} is a member of a group.
1663 bfd_generic_group_name (bfd
*abfd ATTRIBUTE_UNUSED
,
1664 const asection
*sec ATTRIBUTE_UNUSED
)
1671 bfd_generic_discard_group
1674 bool bfd_generic_discard_group (bfd *abfd, asection *group);
1677 Remove all members of @var{group} from the output.
1681 bfd_generic_discard_group (bfd
*abfd ATTRIBUTE_UNUSED
,
1682 asection
*group ATTRIBUTE_UNUSED
)
1688 _bfd_nowrite_set_section_contents (bfd
*abfd
,
1689 sec_ptr section ATTRIBUTE_UNUSED
,
1690 const void *location ATTRIBUTE_UNUSED
,
1691 file_ptr offset ATTRIBUTE_UNUSED
,
1692 bfd_size_type count ATTRIBUTE_UNUSED
)
1694 return _bfd_bool_bfd_false_error (abfd
);
1699 _bfd_section_size_insane
1702 bool _bfd_section_size_insane (bfd *abfd, asection *sec);
1705 Returns true if the given section has a size that indicates
1706 it cannot be read from file. Return false if the size is OK
1707 *or* this function can't say one way or the other.
1712 _bfd_section_size_insane (bfd
*abfd
, asection
*sec
)
1714 bfd_size_type size
= bfd_get_section_limit_octets (abfd
, sec
);
1718 if ((bfd_section_flags (sec
) & SEC_IN_MEMORY
) != 0
1719 /* PR 24753: Linker created sections can be larger than
1720 the file size, eg if they are being used to hold stubs. */
1721 || (bfd_section_flags (sec
) & SEC_LINKER_CREATED
) != 0
1722 /* PR 24753: Sections which have no content should also be
1723 excluded as they contain no size on disk. */
1724 || (bfd_section_flags (sec
) & SEC_HAS_CONTENTS
) == 0
1725 /* The MMO file format supports its own special compression
1726 technique, but it uses COMPRESS_SECTION_NONE when loading
1727 a section's contents. */
1728 || bfd_get_flavour (abfd
) == bfd_target_mmo_flavour
)
1731 ufile_ptr filesize
= bfd_get_file_size (abfd
);
1735 if (sec
->compress_status
== DECOMPRESS_SECTION_ZSTD
1736 || sec
->compress_status
== DECOMPRESS_SECTION_ZLIB
)
1738 /* PR26946, PR28834: Sanity check compress header uncompressed
1739 size against the original file size, and check that the
1740 compressed section can be read from file. We choose an
1741 arbitrary uncompressed size of 10x the file size, rather than
1742 a compress ratio. The reason being that compiling
1743 "int aaa..a;" with "a" repeated enough times can result in
1744 compression ratios without limit for .debug_str, whereas such
1745 a file will usually also have the enormous symbol
1746 uncompressed in .symtab. */
1747 if (size
/ 10 > filesize
)
1749 bfd_set_error (bfd_error_bad_value
);
1752 size
= sec
->compressed_size
;
1755 if ((ufile_ptr
) sec
->filepos
> filesize
|| size
> filesize
- sec
->filepos
)
1757 bfd_set_error (bfd_error_file_truncated
);