1 /* Object file "section" support for the BFD library.
2 Copyright (C) 1990, 91, 92, 93, 94, 95, 96, 97, 98, 99, 2000
3 Free Software Foundation, Inc.
4 Written by Cygnus Support.
6 This file is part of BFD, the Binary File Descriptor library.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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 --------|
118 The data within a section is stored in a @dfn{link_order}.
119 These are much like the fixups in <<gas>>. The link_order
120 abstraction allows a section to grow and shrink within itself.
122 A link_order knows how big it is, and which is the next
123 link_order and where the raw data for it is; it also points to
124 a list of relocations which apply to it.
126 The link_order is used by the linker to perform relaxing on
127 final code. The compiler creates code which is as big as
128 necessary to make it work without relaxing, and the user can
129 select whether to relax. Sometimes relaxing takes a lot of
130 time. The linker runs around the relocations to see if any
131 are attached to data which can be shrunk, if so it does it on
132 a link_order by link_order basis.
145 typedef asection, section prototypes, Section Output, Sections
149 Here is the section structure:
153 .{* This structure is used for a comdat section, as in PE. A comdat
154 . section is associated with a particular symbol. When the linker
155 . sees a comdat section, it keeps only one of the sections with a
156 . given name and associated with a given symbol. *}
158 .struct bfd_comdat_info
160 . {* The name of the symbol associated with a comdat section. *}
163 . {* The local symbol table index of the symbol associated with a
164 . comdat section. This is only meaningful to the object file format
165 . specific code; it is not an index into the list returned by
166 . bfd_canonicalize_symtab. *}
169 . {* If this section is being discarded, the linker uses this field
170 . to point to the input section which is being kept. *}
176 . {* The name of the section; the name isn't a copy, the pointer is
177 . the same as that passed to bfd_make_section. *}
181 . {* A unique sequence number. *}
185 . {* Which section is it; 0..nth. *}
189 . {* The next section in the list belonging to the BFD, or NULL. *}
193 . {* The field flags contains attributes of the section. Some
194 . flags are read in from the object file, and some are
195 . synthesized from other information. *}
199 .#define SEC_NO_FLAGS 0x000
201 . {* Tells the OS to allocate space for this section when loading.
202 . This is clear for a section containing debug information only. *}
203 .#define SEC_ALLOC 0x001
205 . {* Tells the OS to load the section from the file when loading.
206 . This is clear for a .bss section. *}
207 .#define SEC_LOAD 0x002
209 . {* The section contains data still to be relocated, so there is
210 . some relocation information too. *}
211 .#define SEC_RELOC 0x004
213 .#if 0 {* Obsolete ? *}
214 .#define SEC_BALIGN 0x008
217 . {* A signal to the OS that the section contains read only data. *}
218 .#define SEC_READONLY 0x010
220 . {* The section contains code only. *}
221 .#define SEC_CODE 0x020
223 . {* The section contains data only. *}
224 .#define SEC_DATA 0x040
226 . {* The section will reside in ROM. *}
227 .#define SEC_ROM 0x080
229 . {* The section contains constructor information. This section
230 . type is used by the linker to create lists of constructors and
231 . destructors used by <<g++>>. When a back end sees a symbol
232 . which should be used in a constructor list, it creates a new
233 . section for the type of name (e.g., <<__CTOR_LIST__>>), attaches
234 . the symbol to it, and builds a relocation. To build the lists
235 . of constructors, all the linker has to do is catenate all the
236 . sections called <<__CTOR_LIST__>> and relocate the data
237 . contained within - exactly the operations it would peform on
239 .#define SEC_CONSTRUCTOR 0x100
241 . {* The section is a constructor, and should be placed at the
242 . end of the text, data, or bss section(?). *}
243 .#define SEC_CONSTRUCTOR_TEXT 0x1100
244 .#define SEC_CONSTRUCTOR_DATA 0x2100
245 .#define SEC_CONSTRUCTOR_BSS 0x3100
247 . {* The section has contents - a data section could be
248 . <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>; a debug section could be
249 . <<SEC_HAS_CONTENTS>> *}
250 .#define SEC_HAS_CONTENTS 0x200
252 . {* An instruction to the linker to not output the section
253 . even if it has information which would normally be written. *}
254 .#define SEC_NEVER_LOAD 0x400
256 . {* The section is a COFF shared library section. This flag is
257 . only for the linker. If this type of section appears in
258 . the input file, the linker must copy it to the output file
259 . without changing the vma or size. FIXME: Although this
260 . was originally intended to be general, it really is COFF
261 . specific (and the flag was renamed to indicate this). It
262 . might be cleaner to have some more general mechanism to
263 . allow the back end to control what the linker does with
265 .#define SEC_COFF_SHARED_LIBRARY 0x800
267 . {* The section contains common symbols (symbols may be defined
268 . multiple times, the value of a symbol is the amount of
269 . space it requires, and the largest symbol value is the one
270 . used). Most targets have exactly one of these (which we
271 . translate to bfd_com_section_ptr), but ECOFF has two. *}
272 .#define SEC_IS_COMMON 0x8000
274 . {* The section contains only debugging information. For
275 . example, this is set for ELF .debug and .stab sections.
276 . strip tests this flag to see if a section can be
278 .#define SEC_DEBUGGING 0x10000
280 . {* The contents of this section are held in memory pointed to
281 . by the contents field. This is checked by bfd_get_section_contents,
282 . and the data is retrieved from memory if appropriate. *}
283 .#define SEC_IN_MEMORY 0x20000
285 . {* The contents of this section are to be excluded by the
286 . linker for executable and shared objects unless those
287 . objects are to be further relocated. *}
288 .#define SEC_EXCLUDE 0x40000
290 . {* The contents of this section are to be sorted by the
291 . based on the address specified in the associated symbol
293 .#define SEC_SORT_ENTRIES 0x80000
295 . {* When linking, duplicate sections of the same name should be
296 . discarded, rather than being combined into a single section as
297 . is usually done. This is similar to how common symbols are
298 . handled. See SEC_LINK_DUPLICATES below. *}
299 .#define SEC_LINK_ONCE 0x100000
301 . {* If SEC_LINK_ONCE is set, this bitfield describes how the linker
302 . should handle duplicate sections. *}
303 .#define SEC_LINK_DUPLICATES 0x600000
305 . {* This value for SEC_LINK_DUPLICATES means that duplicate
306 . sections with the same name should simply be discarded. *}
307 .#define SEC_LINK_DUPLICATES_DISCARD 0x0
309 . {* This value for SEC_LINK_DUPLICATES means that the linker
310 . should warn if there are any duplicate sections, although
311 . it should still only link one copy. *}
312 .#define SEC_LINK_DUPLICATES_ONE_ONLY 0x200000
314 . {* This value for SEC_LINK_DUPLICATES means that the linker
315 . should warn if any duplicate sections are a different size. *}
316 .#define SEC_LINK_DUPLICATES_SAME_SIZE 0x400000
318 . {* This value for SEC_LINK_DUPLICATES means that the linker
319 . should warn if any duplicate sections contain different
321 .#define SEC_LINK_DUPLICATES_SAME_CONTENTS 0x600000
323 . {* This section was created by the linker as part of dynamic
324 . relocation or other arcane processing. It is skipped when
325 . going through the first-pass output, trusting that someone
326 . else up the line will take care of it later. *}
327 .#define SEC_LINKER_CREATED 0x800000
329 . {* This section should not be subject to garbage collection. *}
330 .#define SEC_KEEP 0x1000000
332 . {* This section contains "short" data, and should be placed
334 .#define SEC_SMALL_DATA 0x2000000
336 . {* This section contains data which may be shared with other
337 . executables or shared objects. *}
338 .#define SEC_SHARED 0x4000000
340 . {* When a section with this flag is being linked, then if the size of
341 . the input section is less than a page, it should not cross a page
342 . boundary. If the size of the input section is one page or more, it
343 . should be aligned on a page boundary. *}
344 .#define SEC_BLOCK 0x8000000
346 . {* Conditionally link this section; do not link if there are no
347 . references found to any symbol in the section. *}
348 .#define SEC_CLINK 0x10000000
350 . {* End of section flags. *}
352 . {* Some internal packed boolean fields. *}
354 . {* See the vma field. *}
355 . unsigned int user_set_vma : 1;
357 . {* Whether relocations have been processed. *}
358 . unsigned int reloc_done : 1;
360 . {* A mark flag used by some of the linker backends. *}
361 . unsigned int linker_mark : 1;
363 . {* A mark flag used by some linker backends for garbage collection. *}
364 . unsigned int gc_mark : 1;
366 . {* Used by the ELF code to mark sections which have been allocated to segments. *}
367 . unsigned int segment_mark : 1;
369 . {* End of internal packed boolean fields. *}
371 . {* The virtual memory address of the section - where it will be
372 . at run time. The symbols are relocated against this. The
373 . user_set_vma flag is maintained by bfd; if it's not set, the
374 . backend can assign addresses (for example, in <<a.out>>, where
375 . the default address for <<.data>> is dependent on the specific
376 . target and various flags). *}
380 . {* The load address of the section - where it would be in a
381 . rom image; really only used for writing section header
386 . {* The size of the section in octets, as it will be output.
387 . Contains a value even if the section has no contents (e.g., the
388 . size of <<.bss>>). This will be filled in after relocation. *}
390 . bfd_size_type _cooked_size;
392 . {* The original size on disk of the section, in octets. Normally this
393 . value is the same as the size, but if some relaxing has
394 . been done, then this value will be bigger. *}
396 . bfd_size_type _raw_size;
398 . {* If this section is going to be output, then this value is the
399 . offset in *bytes* into the output section of the first byte in the
400 . input section (byte ==> smallest addressable unit on the
401 . target). In most cases, if this was going to start at the
402 . 100th octet (8-bit quantity) in the output section, this value
403 . would be 100. However, if the target byte size is 16 bits
404 . (bfd_octets_per_byte is "2"), this value would be 50. *}
406 . bfd_vma output_offset;
408 . {* The output section through which to map on output. *}
410 . struct sec *output_section;
412 . {* The alignment requirement of the section, as an exponent of 2 -
413 . e.g., 3 aligns to 2^3 (or 8). *}
415 . unsigned int alignment_power;
417 . {* If an input section, a pointer to a vector of relocation
418 . records for the data in this section. *}
420 . struct reloc_cache_entry *relocation;
422 . {* If an output section, a pointer to a vector of pointers to
423 . relocation records for the data in this section. *}
425 . struct reloc_cache_entry **orelocation;
427 . {* The number of relocation records in one of the above *}
429 . unsigned reloc_count;
431 . {* Information below is back end specific - and not always used
434 . {* File position of section data. *}
438 . {* File position of relocation info. *}
440 . file_ptr rel_filepos;
442 . {* File position of line data. *}
444 . file_ptr line_filepos;
446 . {* Pointer to data for applications. *}
450 . {* If the SEC_IN_MEMORY flag is set, this points to the actual
452 . unsigned char *contents;
454 . {* Attached line number information. *}
458 . {* Number of line number records. *}
460 . unsigned int lineno_count;
462 . {* Optional information about a COMDAT entry; NULL if not COMDAT. *}
464 . struct bfd_comdat_info *comdat;
466 . {* When a section is being output, this value changes as more
467 . linenumbers are written out. *}
469 . file_ptr moving_line_filepos;
471 . {* What the section number is in the target world. *}
477 . {* If this is a constructor section then here is a list of the
478 . relocations created to relocate items within it. *}
480 . struct relent_chain *constructor_chain;
482 . {* The BFD which owns the section. *}
486 . {* A symbol which points at this section only *}
487 . struct symbol_cache_entry *symbol;
488 . struct symbol_cache_entry **symbol_ptr_ptr;
490 . struct bfd_link_order *link_order_head;
491 . struct bfd_link_order *link_order_tail;
494 .{* These sections are global, and are managed by BFD. The application
495 . and target back end are not permitted to change the values in
496 . these sections. New code should use the section_ptr macros rather
497 . than referring directly to the const sections. The const sections
498 . may eventually vanish. *}
499 .#define BFD_ABS_SECTION_NAME "*ABS*"
500 .#define BFD_UND_SECTION_NAME "*UND*"
501 .#define BFD_COM_SECTION_NAME "*COM*"
502 .#define BFD_IND_SECTION_NAME "*IND*"
504 .{* the absolute section *}
505 .extern const asection bfd_abs_section;
506 .#define bfd_abs_section_ptr ((asection *) &bfd_abs_section)
507 .#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr)
508 .{* Pointer to the undefined section *}
509 .extern const asection bfd_und_section;
510 .#define bfd_und_section_ptr ((asection *) &bfd_und_section)
511 .#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr)
512 .{* Pointer to the common section *}
513 .extern const asection bfd_com_section;
514 .#define bfd_com_section_ptr ((asection *) &bfd_com_section)
515 .{* Pointer to the indirect section *}
516 .extern const asection bfd_ind_section;
517 .#define bfd_ind_section_ptr ((asection *) &bfd_ind_section)
518 .#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr)
520 .extern const struct symbol_cache_entry * const bfd_abs_symbol;
521 .extern const struct symbol_cache_entry * const bfd_com_symbol;
522 .extern const struct symbol_cache_entry * const bfd_und_symbol;
523 .extern const struct symbol_cache_entry * const bfd_ind_symbol;
524 .#define bfd_get_section_size_before_reloc(section) \
525 . ((section)->reloc_done ? (abort (), (bfd_size_type) 1) \
526 . : (section)->_raw_size)
527 .#define bfd_get_section_size_after_reloc(section) \
528 . ((section)->reloc_done ? (section)->_cooked_size \
529 . : (abort (), (bfd_size_type) 1))
532 /* We use a macro to initialize the static asymbol structures because
533 traditional C does not permit us to initialize a union member while
534 gcc warns if we don't initialize it. */
535 /* the_bfd, name, value, attr, section [, udata] */
537 #define GLOBAL_SYM_INIT(NAME, SECTION) \
538 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION, { 0 }}
540 #define GLOBAL_SYM_INIT(NAME, SECTION) \
541 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION }
544 /* These symbols are global, not specific to any BFD. Therefore, anything
545 that tries to change them is broken, and should be repaired. */
547 static const asymbol global_syms[] =
549 GLOBAL_SYM_INIT (BFD_COM_SECTION_NAME, &bfd_com_section),
550 GLOBAL_SYM_INIT (BFD_UND_SECTION_NAME, &bfd_und_section),
551 GLOBAL_SYM_INIT (BFD_ABS_SECTION_NAME, &bfd_abs_section),
552 GLOBAL_SYM_INIT (BFD_IND_SECTION_NAME, &bfd_ind_section)
555 #define STD_SECTION(SEC, FLAGS, SYM, NAME, IDX) \
556 const asymbol * const SYM = (asymbol *) &global_syms[IDX]; \
557 const asection SEC = \
558 /* name, id, index, next, flags, user_set_vma, reloc_done, */ \
559 { NAME, IDX, 0, NULL, FLAGS, 0, 0, \
561 /* linker_mark, gc_mark, segment_mark, vma, lma, _cooked_size, */ \
564 /* _raw_size, output_offset, output_section, alignment_power, */ \
565 0, 0, (struct sec *) &SEC, 0, \
567 /* relocation, orelocation, reloc_count, filepos, rel_filepos, */ \
568 NULL, NULL, 0, 0, 0, \
570 /* line_filepos, userdata, contents, lineno, lineno_count, */ \
571 0, NULL, NULL, NULL, 0, \
573 /* comdat, moving_line_filepos, target_index, used_by_bfd, */ \
576 /* constructor_chain, owner, */ \
580 (struct symbol_cache_entry *) &global_syms[IDX], \
582 /* symbol_ptr_ptr, */ \
583 (struct symbol_cache_entry **) &SYM, \
585 /* link_order_head, link_order_tail */ \
589 STD_SECTION (bfd_com_section, SEC_IS_COMMON, bfd_com_symbol,
590 BFD_COM_SECTION_NAME, 0);
591 STD_SECTION (bfd_und_section, 0, bfd_und_symbol, BFD_UND_SECTION_NAME, 1);
592 STD_SECTION (bfd_abs_section, 0, bfd_abs_symbol, BFD_ABS_SECTION_NAME, 2);
593 STD_SECTION (bfd_ind_section, 0, bfd_ind_symbol, BFD_IND_SECTION_NAME, 3);
599 section prototypes, , typedef asection, Sections
603 These are the functions exported by the section handling part of BFD.
608 bfd_get_section_by_name
611 asection *bfd_get_section_by_name(bfd *abfd, const char *name);
614 Run through @var{abfd} and return the one of the
615 <<asection>>s whose name matches @var{name}, otherwise <<NULL>>.
616 @xref{Sections}, for more information.
618 This should only be used in special cases; the normal way to process
619 all sections of a given name is to use <<bfd_map_over_sections>> and
620 <<strcmp>> on the name (or better yet, base it on the section flags
621 or something else) for each section.
625 bfd_get_section_by_name (abfd, name)
631 for (sect = abfd->sections; sect != NULL; sect = sect->next)
632 if (!strcmp (sect->name, name))
640 bfd_make_section_old_way
643 asection *bfd_make_section_old_way(bfd *abfd, const char *name);
646 Create a new empty section called @var{name}
647 and attach it to the end of the chain of sections for the
648 BFD @var{abfd}. An attempt to create a section with a name which
649 is already in use returns its pointer without changing the
652 It has the funny name since this is the way it used to be
653 before it was rewritten....
656 o <<bfd_error_invalid_operation>> -
657 If output has already started for this BFD.
658 o <<bfd_error_no_memory>> -
659 If memory allocation fails.
665 bfd_make_section_old_way (abfd, name)
669 asection *sec = bfd_get_section_by_name (abfd, name);
670 if (sec == (asection *) NULL)
672 sec = bfd_make_section (abfd, name);
679 bfd_make_section_anyway
682 asection *bfd_make_section_anyway(bfd *abfd, const char *name);
685 Create a new empty section called @var{name} and attach it to the end of
686 the chain of sections for @var{abfd}. Create a new section even if there
687 is already a section with that name.
689 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
690 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
691 o <<bfd_error_no_memory>> - If memory allocation fails.
695 bfd_make_section_anyway (abfd, name)
699 static int section_id = 0x10; /* id 0 to 3 used by STD_SECTION. */
701 asection **prev = &abfd->sections;
702 asection *sect = abfd->sections;
704 if (abfd->output_has_begun)
706 bfd_set_error (bfd_error_invalid_operation);
716 newsect = (asection *) bfd_zalloc (abfd, sizeof (asection));
720 newsect->name = name;
721 newsect->id = section_id++;
722 newsect->index = abfd->section_count++;
723 newsect->flags = SEC_NO_FLAGS;
725 newsect->userdata = NULL;
726 newsect->contents = NULL;
727 newsect->next = (asection *) NULL;
728 newsect->relocation = (arelent *) NULL;
729 newsect->reloc_count = 0;
730 newsect->line_filepos = 0;
731 newsect->owner = abfd;
732 newsect->comdat = NULL;
734 /* Create a symbol whos only job is to point to this section. This is
735 useful for things like relocs which are relative to the base of a
737 newsect->symbol = bfd_make_empty_symbol (abfd);
738 if (newsect->symbol == NULL)
740 newsect->symbol->name = name;
741 newsect->symbol->value = 0;
742 newsect->symbol->section = newsect;
743 newsect->symbol->flags = BSF_SECTION_SYM;
745 newsect->symbol_ptr_ptr = &newsect->symbol;
747 if (BFD_SEND (abfd, _new_section_hook, (abfd, newsect)) != true)
762 asection *bfd_make_section(bfd *, const char *name);
765 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
766 bfd_set_error ()) without changing the section chain if there is already a
767 section named @var{name}. If there is an error, return <<NULL>> and set
772 bfd_make_section (abfd, name)
776 asection *sect = abfd->sections;
778 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0)
780 return bfd_abs_section_ptr;
782 if (strcmp (name, BFD_COM_SECTION_NAME) == 0)
784 return bfd_com_section_ptr;
786 if (strcmp (name, BFD_UND_SECTION_NAME) == 0)
788 return bfd_und_section_ptr;
791 if (strcmp (name, BFD_IND_SECTION_NAME) == 0)
793 return bfd_ind_section_ptr;
798 if (!strcmp (sect->name, name))
803 /* The name is not already used; go ahead and make a new section. */
804 return bfd_make_section_anyway (abfd, name);
810 bfd_set_section_flags
813 boolean bfd_set_section_flags(bfd *abfd, asection *sec, flagword flags);
816 Set the attributes of the section @var{sec} in the BFD
817 @var{abfd} to the value @var{flags}. Return <<true>> on success,
818 <<false>> on error. Possible error returns are:
820 o <<bfd_error_invalid_operation>> -
821 The section cannot have one or more of the attributes
822 requested. For example, a .bss section in <<a.out>> may not
823 have the <<SEC_HAS_CONTENTS>> field set.
829 bfd_set_section_flags (abfd, section, flags)
830 bfd *abfd ATTRIBUTE_UNUSED;
835 /* If you try to copy a text section from an input file (where it
836 has the SEC_CODE flag set) to an output file, this loses big if
837 the bfd_applicable_section_flags (abfd) doesn't have the SEC_CODE
838 set - which it doesn't, at least not for a.out. FIXME */
840 if ((flags & bfd_applicable_section_flags (abfd)) != flags)
842 bfd_set_error (bfd_error_invalid_operation);
847 section->flags = flags;
854 bfd_map_over_sections
857 void bfd_map_over_sections(bfd *abfd,
858 void (*func)(bfd *abfd,
864 Call the provided function @var{func} for each section
865 attached to the BFD @var{abfd}, passing @var{obj} as an
866 argument. The function will be called as if by
868 | func(abfd, the_section, obj);
870 This is the prefered method for iterating over sections; an
871 alternative would be to use a loop:
874 | for (p = abfd->sections; p != NULL; p = p->next)
882 bfd_map_over_sections (abfd, operation, user_storage)
884 void (*operation) PARAMS ((bfd * abfd, asection * sect, PTR obj));
890 for (sect = abfd->sections; sect != NULL; i++, sect = sect->next)
891 (*operation) (abfd, sect, user_storage);
893 if (i != abfd->section_count) /* Debugging */
903 boolean bfd_set_section_size(bfd *abfd, asection *sec, bfd_size_type val);
906 Set @var{sec} to the size @var{val}. If the operation is
907 ok, then <<true>> is returned, else <<false>>.
909 Possible error returns:
910 o <<bfd_error_invalid_operation>> -
911 Writing has started to the BFD, so setting the size is invalid.
916 bfd_set_section_size (abfd, ptr, val)
921 /* Once you've started writing to any section you cannot create or change
922 the size of any others. */
924 if (abfd->output_has_begun)
926 bfd_set_error (bfd_error_invalid_operation);
930 ptr->_cooked_size = val;
931 ptr->_raw_size = val;
938 bfd_set_section_contents
941 boolean bfd_set_section_contents
946 bfd_size_type count);
950 Sets the contents of the section @var{section} in BFD
951 @var{abfd} to the data starting in memory at @var{data}. The
952 data is written to the output section starting at offset
953 @var{offset} for @var{count} octets.
957 Normally <<true>> is returned, else <<false>>. Possible error
959 o <<bfd_error_no_contents>> -
960 The output section does not have the <<SEC_HAS_CONTENTS>>
961 attribute, so nothing can be written to it.
964 This routine is front end to the back end function
965 <<_bfd_set_section_contents>>.
970 #define bfd_get_section_size_now(abfd,sec) \
972 ? bfd_get_section_size_after_reloc (sec) \
973 : bfd_get_section_size_before_reloc (sec))
976 bfd_set_section_contents (abfd, section, location, offset, count)
985 if (!(bfd_get_section_flags (abfd, section) & SEC_HAS_CONTENTS))
987 bfd_set_error (bfd_error_no_contents);
994 bfd_set_error (bfd_error_bad_value);
997 sz = bfd_get_section_size_now (abfd, section);
998 if ((bfd_size_type) offset > sz
1000 || offset + count > sz)
1003 switch (abfd->direction)
1005 case read_direction:
1007 bfd_set_error (bfd_error_invalid_operation);
1010 case write_direction:
1013 case both_direction:
1014 /* File is opened for update. `output_has_begun' some time ago when
1015 the file was created. Do not recompute sections sizes or alignments
1016 in _bfd_set_section_content. */
1017 abfd->output_has_begun = true;
1021 if (BFD_SEND (abfd, _bfd_set_section_contents,
1022 (abfd, section, location, offset, count)))
1024 abfd->output_has_begun = true;
1033 bfd_get_section_contents
1036 boolean bfd_get_section_contents
1037 (bfd *abfd, asection *section, PTR location,
1038 file_ptr offset, bfd_size_type count);
1041 Read data from @var{section} in BFD @var{abfd}
1042 into memory starting at @var{location}. The data is read at an
1043 offset of @var{offset} from the start of the input section,
1044 and is read for @var{count} bytes.
1046 If the contents of a constructor with the <<SEC_CONSTRUCTOR>>
1047 flag set are requested or if the section does not have the
1048 <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled
1049 with zeroes. If no errors occur, <<true>> is returned, else
1056 bfd_get_section_contents (abfd, section, location, offset, count)
1061 bfd_size_type count;
1065 if (section->flags & SEC_CONSTRUCTOR)
1067 memset (location, 0, (unsigned) count);
1074 bfd_set_error (bfd_error_bad_value);
1077 /* Even if reloc_done is true, this function reads unrelocated
1078 contents, so we want the raw size. */
1079 sz = section->_raw_size;
1080 if ((bfd_size_type) offset > sz || count > sz || offset + count > sz)
1087 if ((section->flags & SEC_HAS_CONTENTS) == 0)
1089 memset (location, 0, (unsigned) count);
1093 if ((section->flags & SEC_IN_MEMORY) != 0)
1095 memcpy (location, section->contents + offset, (size_t) count);
1099 return BFD_SEND (abfd, _bfd_get_section_contents,
1100 (abfd, section, location, offset, count));
1105 bfd_copy_private_section_data
1108 boolean bfd_copy_private_section_data(bfd *ibfd, asection *isec, bfd *obfd, asection *osec);
1111 Copy private section information from @var{isec} in the BFD
1112 @var{ibfd} to the section @var{osec} in the BFD @var{obfd}.
1113 Return <<true>> on success, <<false>> on error. Possible error
1116 o <<bfd_error_no_memory>> -
1117 Not enough memory exists to create private data for @var{osec}.
1119 .#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \
1120 . BFD_SEND (obfd, _bfd_copy_private_section_data, \
1121 . (ibfd, isection, obfd, osection))
1126 _bfd_strip_section_from_output
1129 void _bfd_strip_section_from_output
1130 (struct bfd_link_info *info, asection *section);
1133 Remove @var{section} from the output. If the output section
1134 becomes empty, remove it from the output bfd. @var{info} may
1135 be NULL; if it is not, it is used to decide whether the output
1139 _bfd_strip_section_from_output (info, s)
1140 struct bfd_link_info *info;
1143 asection **spp, *os;
1144 struct bfd_link_order *p, *pp;
1147 /* Excise the input section from the link order.
1149 FIXME: For all calls that I can see to this function, the link
1150 orders have not yet been set up. So why are we checking them? --
1152 os = s->output_section;
1153 for (p = os->link_order_head, pp = NULL; p != NULL; pp = p, p = p->next)
1154 if (p->type == bfd_indirect_link_order
1155 && p->u.indirect.section == s)
1160 os->link_order_head = p->next;
1162 os->link_order_tail = pp;
1166 keep_os = os->link_order_head != NULL;
1168 if (! keep_os && info != NULL)
1171 for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link_next)
1174 for (is = abfd->sections; is != NULL; is = is->next)
1176 if (is != s && is->output_section == os)
1186 /* If the output section is empty, remove it too. Careful about sections
1187 that have been discarded in the link script -- they are mapped to
1188 bfd_abs_section, which has no owner. */
1189 if (!keep_os && os->owner != NULL)
1191 for (spp = &os->owner->sections; *spp; spp = &(*spp)->next)
1195 os->owner->section_count--;