section.texi revision 1.1.1.1
1@section Sections 2The raw data contained within a BFD is maintained through the 3section abstraction. A single BFD may have any number of 4sections. It keeps hold of them by pointing to the first; 5each one points to the next in the list. 6 7Sections are supported in BFD in @code{section.c}. 8 9@menu 10* Section Input:: 11* Section Output:: 12* typedef asection:: 13* section prototypes:: 14@end menu 15 16@node Section Input, Section Output, Sections, Sections 17@subsection Section input 18When a BFD is opened for reading, the section structures are 19created and attached to the BFD. 20 21Each section has a name which describes the section in the 22outside world---for example, @code{a.out} would contain at least 23three sections, called @code{.text}, @code{.data} and @code{.bss}. 24 25Names need not be unique; for example a COFF file may have several 26sections named @code{.data}. 27 28Sometimes a BFD will contain more than the ``natural'' number of 29sections. A back end may attach other sections containing 30constructor data, or an application may add a section (using 31@code{bfd_make_section}) to the sections attached to an already open 32BFD. For example, the linker creates an extra section 33@code{COMMON} for each input file's BFD to hold information about 34common storage. 35 36The raw data is not necessarily read in when 37the section descriptor is created. Some targets may leave the 38data in place until a @code{bfd_get_section_contents} call is 39made. Other back ends may read in all the data at once. For 40example, an S-record file has to be read once to determine the 41size of the data. An IEEE-695 file doesn't contain raw data in 42sections, but data and relocation expressions intermixed, so 43the data area has to be parsed to get out the data and 44relocations. 45 46@node Section Output, typedef asection, Section Input, Sections 47@subsection Section output 48To write a new object style BFD, the various sections to be 49written have to be created. They are attached to the BFD in 50the same way as input sections; data is written to the 51sections using @code{bfd_set_section_contents}. 52 53Any program that creates or combines sections (e.g., the assembler 54and linker) must use the @code{asection} fields @code{output_section} and 55@code{output_offset} to indicate the file sections to which each 56section must be written. (If the section is being created from 57scratch, @code{output_section} should probably point to the section 58itself and @code{output_offset} should probably be zero.) 59 60The data to be written comes from input sections attached 61(via @code{output_section} pointers) to 62the output sections. The output section structure can be 63considered a filter for the input section: the output section 64determines the vma of the output data and the name, but the 65input section determines the offset into the output section of 66the data to be written. 67 68E.g., to create a section "O", starting at 0x100, 0x123 long, 69containing two subsections, "A" at offset 0x0 (i.e., at vma 700x100) and "B" at offset 0x20 (i.e., at vma 0x120) the @code{asection} 71structures would look like: 72 73@example 74 section name "A" 75 output_offset 0x00 76 size 0x20 77 output_section -----------> section name "O" 78 | vma 0x100 79 section name "B" | size 0x123 80 output_offset 0x20 | 81 size 0x103 | 82 output_section --------| 83@end example 84 85@subsection Link orders 86The data within a section is stored in a @dfn{link_order}. 87These are much like the fixups in @code{gas}. The link_order 88abstraction allows a section to grow and shrink within itself. 89 90A link_order knows how big it is, and which is the next 91link_order and where the raw data for it is; it also points to 92a list of relocations which apply to it. 93 94The link_order is used by the linker to perform relaxing on 95final code. The compiler creates code which is as big as 96necessary to make it work without relaxing, and the user can 97select whether to relax. Sometimes relaxing takes a lot of 98time. The linker runs around the relocations to see if any 99are attached to data which can be shrunk, if so it does it on 100a link_order by link_order basis. 101 102 103@node typedef asection, section prototypes, Section Output, Sections 104@subsection typedef asection 105Here is the section structure: 106 107 108@example 109 110typedef struct bfd_section 111@{ 112 /* The name of the section; the name isn't a copy, the pointer is 113 the same as that passed to bfd_make_section. */ 114 const char *name; 115 116 /* A unique sequence number. */ 117 int id; 118 119 /* Which section in the bfd; 0..n-1 as sections are created in a bfd. */ 120 int index; 121 122 /* The next section in the list belonging to the BFD, or NULL. */ 123 struct bfd_section *next; 124 125 /* The previous section in the list belonging to the BFD, or NULL. */ 126 struct bfd_section *prev; 127 128 /* The field flags contains attributes of the section. Some 129 flags are read in from the object file, and some are 130 synthesized from other information. */ 131 flagword flags; 132 133#define SEC_NO_FLAGS 0x000 134 135 /* Tells the OS to allocate space for this section when loading. 136 This is clear for a section containing debug information only. */ 137#define SEC_ALLOC 0x001 138 139 /* Tells the OS to load the section from the file when loading. 140 This is clear for a .bss section. */ 141#define SEC_LOAD 0x002 142 143 /* The section contains data still to be relocated, so there is 144 some relocation information too. */ 145#define SEC_RELOC 0x004 146 147 /* A signal to the OS that the section contains read only data. */ 148#define SEC_READONLY 0x008 149 150 /* The section contains code only. */ 151#define SEC_CODE 0x010 152 153 /* The section contains data only. */ 154#define SEC_DATA 0x020 155 156 /* The section will reside in ROM. */ 157#define SEC_ROM 0x040 158 159 /* The section contains constructor information. This section 160 type is used by the linker to create lists of constructors and 161 destructors used by @code{g++}. When a back end sees a symbol 162 which should be used in a constructor list, it creates a new 163 section for the type of name (e.g., @code{__CTOR_LIST__}), attaches 164 the symbol to it, and builds a relocation. To build the lists 165 of constructors, all the linker has to do is catenate all the 166 sections called @code{__CTOR_LIST__} and relocate the data 167 contained within - exactly the operations it would peform on 168 standard data. */ 169#define SEC_CONSTRUCTOR 0x080 170 171 /* The section has contents - a data section could be 172 @code{SEC_ALLOC} | @code{SEC_HAS_CONTENTS}; a debug section could be 173 @code{SEC_HAS_CONTENTS} */ 174#define SEC_HAS_CONTENTS 0x100 175 176 /* An instruction to the linker to not output the section 177 even if it has information which would normally be written. */ 178#define SEC_NEVER_LOAD 0x200 179 180 /* The section contains thread local data. */ 181#define SEC_THREAD_LOCAL 0x400 182 183 /* The section has GOT references. This flag is only for the 184 linker, and is currently only used by the elf32-hppa back end. 185 It will be set if global offset table references were detected 186 in this section, which indicate to the linker that the section 187 contains PIC code, and must be handled specially when doing a 188 static link. */ 189#define SEC_HAS_GOT_REF 0x800 190 191 /* The section contains common symbols (symbols may be defined 192 multiple times, the value of a symbol is the amount of 193 space it requires, and the largest symbol value is the one 194 used). Most targets have exactly one of these (which we 195 translate to bfd_com_section_ptr), but ECOFF has two. */ 196#define SEC_IS_COMMON 0x1000 197 198 /* The section contains only debugging information. For 199 example, this is set for ELF .debug and .stab sections. 200 strip tests this flag to see if a section can be 201 discarded. */ 202#define SEC_DEBUGGING 0x2000 203 204 /* The contents of this section are held in memory pointed to 205 by the contents field. This is checked by bfd_get_section_contents, 206 and the data is retrieved from memory if appropriate. */ 207#define SEC_IN_MEMORY 0x4000 208 209 /* The contents of this section are to be excluded by the 210 linker for executable and shared objects unless those 211 objects are to be further relocated. */ 212#define SEC_EXCLUDE 0x8000 213 214 /* The contents of this section are to be sorted based on the sum of 215 the symbol and addend values specified by the associated relocation 216 entries. Entries without associated relocation entries will be 217 appended to the end of the section in an unspecified order. */ 218#define SEC_SORT_ENTRIES 0x10000 219 220 /* When linking, duplicate sections of the same name should be 221 discarded, rather than being combined into a single section as 222 is usually done. This is similar to how common symbols are 223 handled. See SEC_LINK_DUPLICATES below. */ 224#define SEC_LINK_ONCE 0x20000 225 226 /* If SEC_LINK_ONCE is set, this bitfield describes how the linker 227 should handle duplicate sections. */ 228#define SEC_LINK_DUPLICATES 0xc0000 229 230 /* This value for SEC_LINK_DUPLICATES means that duplicate 231 sections with the same name should simply be discarded. */ 232#define SEC_LINK_DUPLICATES_DISCARD 0x0 233 234 /* This value for SEC_LINK_DUPLICATES means that the linker 235 should warn if there are any duplicate sections, although 236 it should still only link one copy. */ 237#define SEC_LINK_DUPLICATES_ONE_ONLY 0x40000 238 239 /* This value for SEC_LINK_DUPLICATES means that the linker 240 should warn if any duplicate sections are a different size. */ 241#define SEC_LINK_DUPLICATES_SAME_SIZE 0x80000 242 243 /* This value for SEC_LINK_DUPLICATES means that the linker 244 should warn if any duplicate sections contain different 245 contents. */ 246#define SEC_LINK_DUPLICATES_SAME_CONTENTS \ 247 (SEC_LINK_DUPLICATES_ONE_ONLY | SEC_LINK_DUPLICATES_SAME_SIZE) 248 249 /* This section was created by the linker as part of dynamic 250 relocation or other arcane processing. It is skipped when 251 going through the first-pass output, trusting that someone 252 else up the line will take care of it later. */ 253#define SEC_LINKER_CREATED 0x100000 254 255 /* This section should not be subject to garbage collection. 256 Also set to inform the linker that this section should not be 257 listed in the link map as discarded. */ 258#define SEC_KEEP 0x200000 259 260 /* This section contains "short" data, and should be placed 261 "near" the GP. */ 262#define SEC_SMALL_DATA 0x400000 263 264 /* Attempt to merge identical entities in the section. 265 Entity size is given in the entsize field. */ 266#define SEC_MERGE 0x800000 267 268 /* If given with SEC_MERGE, entities to merge are zero terminated 269 strings where entsize specifies character size instead of fixed 270 size entries. */ 271#define SEC_STRINGS 0x1000000 272 273 /* This section contains data about section groups. */ 274#define SEC_GROUP 0x2000000 275 276 /* The section is a COFF shared library section. This flag is 277 only for the linker. If this type of section appears in 278 the input file, the linker must copy it to the output file 279 without changing the vma or size. FIXME: Although this 280 was originally intended to be general, it really is COFF 281 specific (and the flag was renamed to indicate this). It 282 might be cleaner to have some more general mechanism to 283 allow the back end to control what the linker does with 284 sections. */ 285#define SEC_COFF_SHARED_LIBRARY 0x4000000 286 287 /* This section contains data which may be shared with other 288 executables or shared objects. This is for COFF only. */ 289#define SEC_COFF_SHARED 0x8000000 290 291 /* When a section with this flag is being linked, then if the size of 292 the input section is less than a page, it should not cross a page 293 boundary. If the size of the input section is one page or more, 294 it should be aligned on a page boundary. This is for TI 295 TMS320C54X only. */ 296#define SEC_TIC54X_BLOCK 0x10000000 297 298 /* Conditionally link this section; do not link if there are no 299 references found to any symbol in the section. This is for TI 300 TMS320C54X only. */ 301#define SEC_TIC54X_CLINK 0x20000000 302 303 /* End of section flags. */ 304 305 /* Some internal packed boolean fields. */ 306 307 /* See the vma field. */ 308 unsigned int user_set_vma : 1; 309 310 /* A mark flag used by some of the linker backends. */ 311 unsigned int linker_mark : 1; 312 313 /* Another mark flag used by some of the linker backends. Set for 314 output sections that have an input section. */ 315 unsigned int linker_has_input : 1; 316 317 /* Mark flag used by some linker backends for garbage collection. */ 318 unsigned int gc_mark : 1; 319 320 /* The following flags are used by the ELF linker. */ 321 322 /* Mark sections which have been allocated to segments. */ 323 unsigned int segment_mark : 1; 324 325 /* Type of sec_info information. */ 326 unsigned int sec_info_type:3; 327#define ELF_INFO_TYPE_NONE 0 328#define ELF_INFO_TYPE_STABS 1 329#define ELF_INFO_TYPE_MERGE 2 330#define ELF_INFO_TYPE_EH_FRAME 3 331#define ELF_INFO_TYPE_JUST_SYMS 4 332 333 /* Nonzero if this section uses RELA relocations, rather than REL. */ 334 unsigned int use_rela_p:1; 335 336 /* Bits used by various backends. The generic code doesn't touch 337 these fields. */ 338 339 /* Nonzero if this section has TLS related relocations. */ 340 unsigned int has_tls_reloc:1; 341 342 /* Nonzero if this section has a gp reloc. */ 343 unsigned int has_gp_reloc:1; 344 345 /* Nonzero if this section needs the relax finalize pass. */ 346 unsigned int need_finalize_relax:1; 347 348 /* Whether relocations have been processed. */ 349 unsigned int reloc_done : 1; 350 351 /* End of internal packed boolean fields. */ 352 353 /* The virtual memory address of the section - where it will be 354 at run time. The symbols are relocated against this. The 355 user_set_vma flag is maintained by bfd; if it's not set, the 356 backend can assign addresses (for example, in @code{a.out}, where 357 the default address for @code{.data} is dependent on the specific 358 target and various flags). */ 359 bfd_vma vma; 360 361 /* The load address of the section - where it would be in a 362 rom image; really only used for writing section header 363 information. */ 364 bfd_vma lma; 365 366 /* The size of the section in octets, as it will be output. 367 Contains a value even if the section has no contents (e.g., the 368 size of @code{.bss}). */ 369 bfd_size_type size; 370 371 /* For input sections, the original size on disk of the section, in 372 octets. This field should be set for any section whose size is 373 changed by linker relaxation. It is required for sections where 374 the linker relaxation scheme doesn't cache altered section and 375 reloc contents (stabs, eh_frame, SEC_MERGE, some coff relaxing 376 targets), and thus the original size needs to be kept to read the 377 section multiple times. For output sections, rawsize holds the 378 section size calculated on a previous linker relaxation pass. */ 379 bfd_size_type rawsize; 380 381 /* If this section is going to be output, then this value is the 382 offset in *bytes* into the output section of the first byte in the 383 input section (byte ==> smallest addressable unit on the 384 target). In most cases, if this was going to start at the 385 100th octet (8-bit quantity) in the output section, this value 386 would be 100. However, if the target byte size is 16 bits 387 (bfd_octets_per_byte is "2"), this value would be 50. */ 388 bfd_vma output_offset; 389 390 /* The output section through which to map on output. */ 391 struct bfd_section *output_section; 392 393 /* The alignment requirement of the section, as an exponent of 2 - 394 e.g., 3 aligns to 2^3 (or 8). */ 395 unsigned int alignment_power; 396 397 /* If an input section, a pointer to a vector of relocation 398 records for the data in this section. */ 399 struct reloc_cache_entry *relocation; 400 401 /* If an output section, a pointer to a vector of pointers to 402 relocation records for the data in this section. */ 403 struct reloc_cache_entry **orelocation; 404 405 /* The number of relocation records in one of the above. */ 406 unsigned reloc_count; 407 408 /* Information below is back end specific - and not always used 409 or updated. */ 410 411 /* File position of section data. */ 412 file_ptr filepos; 413 414 /* File position of relocation info. */ 415 file_ptr rel_filepos; 416 417 /* File position of line data. */ 418 file_ptr line_filepos; 419 420 /* Pointer to data for applications. */ 421 void *userdata; 422 423 /* If the SEC_IN_MEMORY flag is set, this points to the actual 424 contents. */ 425 unsigned char *contents; 426 427 /* Attached line number information. */ 428 alent *lineno; 429 430 /* Number of line number records. */ 431 unsigned int lineno_count; 432 433 /* Entity size for merging purposes. */ 434 unsigned int entsize; 435 436 /* Points to the kept section if this section is a link-once section, 437 and is discarded. */ 438 struct bfd_section *kept_section; 439 440 /* When a section is being output, this value changes as more 441 linenumbers are written out. */ 442 file_ptr moving_line_filepos; 443 444 /* What the section number is in the target world. */ 445 int target_index; 446 447 void *used_by_bfd; 448 449 /* If this is a constructor section then here is a list of the 450 relocations created to relocate items within it. */ 451 struct relent_chain *constructor_chain; 452 453 /* The BFD which owns the section. */ 454 bfd *owner; 455 456 /* A symbol which points at this section only. */ 457 struct bfd_symbol *symbol; 458 struct bfd_symbol **symbol_ptr_ptr; 459 460 /* Early in the link process, map_head and map_tail are used to build 461 a list of input sections attached to an output section. Later, 462 output sections use these fields for a list of bfd_link_order 463 structs. */ 464 union @{ 465 struct bfd_link_order *link_order; 466 struct bfd_section *s; 467 @} map_head, map_tail; 468@} asection; 469 470/* These sections are global, and are managed by BFD. The application 471 and target back end are not permitted to change the values in 472 these sections. New code should use the section_ptr macros rather 473 than referring directly to the const sections. The const sections 474 may eventually vanish. */ 475#define BFD_ABS_SECTION_NAME "*ABS*" 476#define BFD_UND_SECTION_NAME "*UND*" 477#define BFD_COM_SECTION_NAME "*COM*" 478#define BFD_IND_SECTION_NAME "*IND*" 479 480/* The absolute section. */ 481extern asection bfd_abs_section; 482#define bfd_abs_section_ptr ((asection *) &bfd_abs_section) 483#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr) 484/* Pointer to the undefined section. */ 485extern asection bfd_und_section; 486#define bfd_und_section_ptr ((asection *) &bfd_und_section) 487#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr) 488/* Pointer to the common section. */ 489extern asection bfd_com_section; 490#define bfd_com_section_ptr ((asection *) &bfd_com_section) 491/* Pointer to the indirect section. */ 492extern asection bfd_ind_section; 493#define bfd_ind_section_ptr ((asection *) &bfd_ind_section) 494#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr) 495 496#define bfd_is_const_section(SEC) \ 497 ( ((SEC) == bfd_abs_section_ptr) \ 498 || ((SEC) == bfd_und_section_ptr) \ 499 || ((SEC) == bfd_com_section_ptr) \ 500 || ((SEC) == bfd_ind_section_ptr)) 501 502/* Macros to handle insertion and deletion of a bfd's sections. These 503 only handle the list pointers, ie. do not adjust section_count, 504 target_index etc. */ 505#define bfd_section_list_remove(ABFD, S) \ 506 do \ 507 @{ \ 508 asection *_s = S; \ 509 asection *_next = _s->next; \ 510 asection *_prev = _s->prev; \ 511 if (_prev) \ 512 _prev->next = _next; \ 513 else \ 514 (ABFD)->sections = _next; \ 515 if (_next) \ 516 _next->prev = _prev; \ 517 else \ 518 (ABFD)->section_last = _prev; \ 519 @} \ 520 while (0) 521#define bfd_section_list_append(ABFD, S) \ 522 do \ 523 @{ \ 524 asection *_s = S; \ 525 bfd *_abfd = ABFD; \ 526 _s->next = NULL; \ 527 if (_abfd->section_last) \ 528 @{ \ 529 _s->prev = _abfd->section_last; \ 530 _abfd->section_last->next = _s; \ 531 @} \ 532 else \ 533 @{ \ 534 _s->prev = NULL; \ 535 _abfd->sections = _s; \ 536 @} \ 537 _abfd->section_last = _s; \ 538 @} \ 539 while (0) 540#define bfd_section_list_prepend(ABFD, S) \ 541 do \ 542 @{ \ 543 asection *_s = S; \ 544 bfd *_abfd = ABFD; \ 545 _s->prev = NULL; \ 546 if (_abfd->sections) \ 547 @{ \ 548 _s->next = _abfd->sections; \ 549 _abfd->sections->prev = _s; \ 550 @} \ 551 else \ 552 @{ \ 553 _s->next = NULL; \ 554 _abfd->section_last = _s; \ 555 @} \ 556 _abfd->sections = _s; \ 557 @} \ 558 while (0) 559#define bfd_section_list_insert_after(ABFD, A, S) \ 560 do \ 561 @{ \ 562 asection *_a = A; \ 563 asection *_s = S; \ 564 asection *_next = _a->next; \ 565 _s->next = _next; \ 566 _s->prev = _a; \ 567 _a->next = _s; \ 568 if (_next) \ 569 _next->prev = _s; \ 570 else \ 571 (ABFD)->section_last = _s; \ 572 @} \ 573 while (0) 574#define bfd_section_list_insert_before(ABFD, B, S) \ 575 do \ 576 @{ \ 577 asection *_b = B; \ 578 asection *_s = S; \ 579 asection *_prev = _b->prev; \ 580 _s->prev = _prev; \ 581 _s->next = _b; \ 582 _b->prev = _s; \ 583 if (_prev) \ 584 _prev->next = _s; \ 585 else \ 586 (ABFD)->sections = _s; \ 587 @} \ 588 while (0) 589#define bfd_section_removed_from_list(ABFD, S) \ 590 ((S)->next == NULL ? (ABFD)->section_last != (S) : (S)->next->prev != (S)) 591 592#define BFD_FAKE_SECTION(SEC, FLAGS, SYM, NAME, IDX) \ 593 /* name, id, index, next, prev, flags, user_set_vma, */ \ 594 @{ NAME, IDX, 0, NULL, NULL, FLAGS, 0, \ 595 \ 596 /* linker_mark, linker_has_input, gc_mark, */ \ 597 0, 0, 1, \ 598 \ 599 /* segment_mark, sec_info_type, use_rela_p, has_tls_reloc, */ \ 600 0, 0, 0, 0, \ 601 \ 602 /* has_gp_reloc, need_finalize_relax, reloc_done, */ \ 603 0, 0, 0, \ 604 \ 605 /* vma, lma, size, rawsize */ \ 606 0, 0, 0, 0, \ 607 \ 608 /* output_offset, output_section, alignment_power, */ \ 609 0, (struct bfd_section *) &SEC, 0, \ 610 \ 611 /* relocation, orelocation, reloc_count, filepos, rel_filepos, */ \ 612 NULL, NULL, 0, 0, 0, \ 613 \ 614 /* line_filepos, userdata, contents, lineno, lineno_count, */ \ 615 0, NULL, NULL, NULL, 0, \ 616 \ 617 /* entsize, kept_section, moving_line_filepos, */ \ 618 0, NULL, 0, \ 619 \ 620 /* target_index, used_by_bfd, constructor_chain, owner, */ \ 621 0, NULL, NULL, NULL, \ 622 \ 623 /* symbol, symbol_ptr_ptr, */ \ 624 (struct bfd_symbol *) SYM, &SEC.symbol, \ 625 \ 626 /* map_head, map_tail */ \ 627 @{ NULL @}, @{ NULL @} \ 628 @} 629 630@end example 631 632@node section prototypes, , typedef asection, Sections 633@subsection Section prototypes 634These are the functions exported by the section handling part of BFD. 635 636@findex bfd_section_list_clear 637@subsubsection @code{bfd_section_list_clear} 638@strong{Synopsis} 639@example 640void bfd_section_list_clear (bfd *); 641@end example 642@strong{Description}@* 643Clears the section list, and also resets the section count and 644hash table entries. 645 646@findex bfd_get_section_by_name 647@subsubsection @code{bfd_get_section_by_name} 648@strong{Synopsis} 649@example 650asection *bfd_get_section_by_name (bfd *abfd, const char *name); 651@end example 652@strong{Description}@* 653Run through @var{abfd} and return the one of the 654@code{asection}s whose name matches @var{name}, otherwise @code{NULL}. 655@xref{Sections}, for more information. 656 657This should only be used in special cases; the normal way to process 658all sections of a given name is to use @code{bfd_map_over_sections} and 659@code{strcmp} on the name (or better yet, base it on the section flags 660or something else) for each section. 661 662@findex bfd_get_section_by_name_if 663@subsubsection @code{bfd_get_section_by_name_if} 664@strong{Synopsis} 665@example 666asection *bfd_get_section_by_name_if 667 (bfd *abfd, 668 const char *name, 669 bfd_boolean (*func) (bfd *abfd, asection *sect, void *obj), 670 void *obj); 671@end example 672@strong{Description}@* 673Call the provided function @var{func} for each section 674attached to the BFD @var{abfd} whose name matches @var{name}, 675passing @var{obj} as an argument. The function will be called 676as if by 677 678@example 679 func (abfd, the_section, obj); 680@end example 681 682It returns the first section for which @var{func} returns true, 683otherwise @code{NULL}. 684 685@findex bfd_get_unique_section_name 686@subsubsection @code{bfd_get_unique_section_name} 687@strong{Synopsis} 688@example 689char *bfd_get_unique_section_name 690 (bfd *abfd, const char *templat, int *count); 691@end example 692@strong{Description}@* 693Invent a section name that is unique in @var{abfd} by tacking 694a dot and a digit suffix onto the original @var{templat}. If 695@var{count} is non-NULL, then it specifies the first number 696tried as a suffix to generate a unique name. The value 697pointed to by @var{count} will be incremented in this case. 698 699@findex bfd_make_section_old_way 700@subsubsection @code{bfd_make_section_old_way} 701@strong{Synopsis} 702@example 703asection *bfd_make_section_old_way (bfd *abfd, const char *name); 704@end example 705@strong{Description}@* 706Create a new empty section called @var{name} 707and attach it to the end of the chain of sections for the 708BFD @var{abfd}. An attempt to create a section with a name which 709is already in use returns its pointer without changing the 710section chain. 711 712It has the funny name since this is the way it used to be 713before it was rewritten.... 714 715Possible errors are: 716@itemize @bullet 717 718@item 719@code{bfd_error_invalid_operation} - 720If output has already started for this BFD. 721@item 722@code{bfd_error_no_memory} - 723If memory allocation fails. 724@end itemize 725 726@findex bfd_make_section_anyway_with_flags 727@subsubsection @code{bfd_make_section_anyway_with_flags} 728@strong{Synopsis} 729@example 730asection *bfd_make_section_anyway_with_flags 731 (bfd *abfd, const char *name, flagword flags); 732@end example 733@strong{Description}@* 734Create a new empty section called @var{name} and attach it to the end of 735the chain of sections for @var{abfd}. Create a new section even if there 736is already a section with that name. Also set the attributes of the 737new section to the value @var{flags}. 738 739Return @code{NULL} and set @code{bfd_error} on error; possible errors are: 740@itemize @bullet 741 742@item 743@code{bfd_error_invalid_operation} - If output has already started for @var{abfd}. 744@item 745@code{bfd_error_no_memory} - If memory allocation fails. 746@end itemize 747 748@findex bfd_make_section_anyway 749@subsubsection @code{bfd_make_section_anyway} 750@strong{Synopsis} 751@example 752asection *bfd_make_section_anyway (bfd *abfd, const char *name); 753@end example 754@strong{Description}@* 755Create a new empty section called @var{name} and attach it to the end of 756the chain of sections for @var{abfd}. Create a new section even if there 757is already a section with that name. 758 759Return @code{NULL} and set @code{bfd_error} on error; possible errors are: 760@itemize @bullet 761 762@item 763@code{bfd_error_invalid_operation} - If output has already started for @var{abfd}. 764@item 765@code{bfd_error_no_memory} - If memory allocation fails. 766@end itemize 767 768@findex bfd_make_section_with_flags 769@subsubsection @code{bfd_make_section_with_flags} 770@strong{Synopsis} 771@example 772asection *bfd_make_section_with_flags 773 (bfd *, const char *name, flagword flags); 774@end example 775@strong{Description}@* 776Like @code{bfd_make_section_anyway}, but return @code{NULL} (without calling 777bfd_set_error ()) without changing the section chain if there is already a 778section named @var{name}. Also set the attributes of the new section to 779the value @var{flags}. If there is an error, return @code{NULL} and set 780@code{bfd_error}. 781 782@findex bfd_make_section 783@subsubsection @code{bfd_make_section} 784@strong{Synopsis} 785@example 786asection *bfd_make_section (bfd *, const char *name); 787@end example 788@strong{Description}@* 789Like @code{bfd_make_section_anyway}, but return @code{NULL} (without calling 790bfd_set_error ()) without changing the section chain if there is already a 791section named @var{name}. If there is an error, return @code{NULL} and set 792@code{bfd_error}. 793 794@findex bfd_set_section_flags 795@subsubsection @code{bfd_set_section_flags} 796@strong{Synopsis} 797@example 798bfd_boolean bfd_set_section_flags 799 (bfd *abfd, asection *sec, flagword flags); 800@end example 801@strong{Description}@* 802Set the attributes of the section @var{sec} in the BFD 803@var{abfd} to the value @var{flags}. Return @code{TRUE} on success, 804@code{FALSE} on error. Possible error returns are: 805 806@itemize @bullet 807 808@item 809@code{bfd_error_invalid_operation} - 810The section cannot have one or more of the attributes 811requested. For example, a .bss section in @code{a.out} may not 812have the @code{SEC_HAS_CONTENTS} field set. 813@end itemize 814 815@findex bfd_map_over_sections 816@subsubsection @code{bfd_map_over_sections} 817@strong{Synopsis} 818@example 819void bfd_map_over_sections 820 (bfd *abfd, 821 void (*func) (bfd *abfd, asection *sect, void *obj), 822 void *obj); 823@end example 824@strong{Description}@* 825Call the provided function @var{func} for each section 826attached to the BFD @var{abfd}, passing @var{obj} as an 827argument. The function will be called as if by 828 829@example 830 func (abfd, the_section, obj); 831@end example 832 833This is the preferred method for iterating over sections; an 834alternative would be to use a loop: 835 836@example 837 section *p; 838 for (p = abfd->sections; p != NULL; p = p->next) 839 func (abfd, p, ...) 840@end example 841 842@findex bfd_sections_find_if 843@subsubsection @code{bfd_sections_find_if} 844@strong{Synopsis} 845@example 846asection *bfd_sections_find_if 847 (bfd *abfd, 848 bfd_boolean (*operation) (bfd *abfd, asection *sect, void *obj), 849 void *obj); 850@end example 851@strong{Description}@* 852Call the provided function @var{operation} for each section 853attached to the BFD @var{abfd}, passing @var{obj} as an 854argument. The function will be called as if by 855 856@example 857 operation (abfd, the_section, obj); 858@end example 859 860It returns the first section for which @var{operation} returns true. 861 862@findex bfd_set_section_size 863@subsubsection @code{bfd_set_section_size} 864@strong{Synopsis} 865@example 866bfd_boolean bfd_set_section_size 867 (bfd *abfd, asection *sec, bfd_size_type val); 868@end example 869@strong{Description}@* 870Set @var{sec} to the size @var{val}. If the operation is 871ok, then @code{TRUE} is returned, else @code{FALSE}. 872 873Possible error returns: 874@itemize @bullet 875 876@item 877@code{bfd_error_invalid_operation} - 878Writing has started to the BFD, so setting the size is invalid. 879@end itemize 880 881@findex bfd_set_section_contents 882@subsubsection @code{bfd_set_section_contents} 883@strong{Synopsis} 884@example 885bfd_boolean bfd_set_section_contents 886 (bfd *abfd, asection *section, const void *data, 887 file_ptr offset, bfd_size_type count); 888@end example 889@strong{Description}@* 890Sets the contents of the section @var{section} in BFD 891@var{abfd} to the data starting in memory at @var{data}. The 892data is written to the output section starting at offset 893@var{offset} for @var{count} octets. 894 895Normally @code{TRUE} is returned, else @code{FALSE}. Possible error 896returns are: 897@itemize @bullet 898 899@item 900@code{bfd_error_no_contents} - 901The output section does not have the @code{SEC_HAS_CONTENTS} 902attribute, so nothing can be written to it. 903@item 904and some more too 905@end itemize 906This routine is front end to the back end function 907@code{_bfd_set_section_contents}. 908 909@findex bfd_get_section_contents 910@subsubsection @code{bfd_get_section_contents} 911@strong{Synopsis} 912@example 913bfd_boolean bfd_get_section_contents 914 (bfd *abfd, asection *section, void *location, file_ptr offset, 915 bfd_size_type count); 916@end example 917@strong{Description}@* 918Read data from @var{section} in BFD @var{abfd} 919into memory starting at @var{location}. The data is read at an 920offset of @var{offset} from the start of the input section, 921and is read for @var{count} bytes. 922 923If the contents of a constructor with the @code{SEC_CONSTRUCTOR} 924flag set are requested or if the section does not have the 925@code{SEC_HAS_CONTENTS} flag set, then the @var{location} is filled 926with zeroes. If no errors occur, @code{TRUE} is returned, else 927@code{FALSE}. 928 929@findex bfd_malloc_and_get_section 930@subsubsection @code{bfd_malloc_and_get_section} 931@strong{Synopsis} 932@example 933bfd_boolean bfd_malloc_and_get_section 934 (bfd *abfd, asection *section, bfd_byte **buf); 935@end example 936@strong{Description}@* 937Read all data from @var{section} in BFD @var{abfd} 938into a buffer, *@var{buf}, malloc'd by this function. 939 940@findex bfd_copy_private_section_data 941@subsubsection @code{bfd_copy_private_section_data} 942@strong{Synopsis} 943@example 944bfd_boolean bfd_copy_private_section_data 945 (bfd *ibfd, asection *isec, bfd *obfd, asection *osec); 946@end example 947@strong{Description}@* 948Copy private section information from @var{isec} in the BFD 949@var{ibfd} to the section @var{osec} in the BFD @var{obfd}. 950Return @code{TRUE} on success, @code{FALSE} on error. Possible error 951returns are: 952 953@itemize @bullet 954 955@item 956@code{bfd_error_no_memory} - 957Not enough memory exists to create private data for @var{osec}. 958@end itemize 959@example 960#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \ 961 BFD_SEND (obfd, _bfd_copy_private_section_data, \ 962 (ibfd, isection, obfd, osection)) 963@end example 964 965@findex bfd_generic_is_group_section 966@subsubsection @code{bfd_generic_is_group_section} 967@strong{Synopsis} 968@example 969bfd_boolean bfd_generic_is_group_section (bfd *, const asection *sec); 970@end example 971@strong{Description}@* 972Returns TRUE if @var{sec} is a member of a group. 973 974@findex bfd_generic_discard_group 975@subsubsection @code{bfd_generic_discard_group} 976@strong{Synopsis} 977@example 978bfd_boolean bfd_generic_discard_group (bfd *abfd, asection *group); 979@end example 980@strong{Description}@* 981Remove all members of @var{group} from the output. 982 983