section.c revision 77298
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. 5 6This file is part of BFD, the Binary File Descriptor library. 7 8This program is free software; you can redistribute it and/or modify 9it under the terms of the GNU General Public License as published by 10the Free Software Foundation; either version 2 of the License, or 11(at your option) any later version. 12 13This program is distributed in the hope that it will be useful, 14but WITHOUT ANY WARRANTY; without even the implied warranty of 15MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16GNU General Public License for more details. 17 18You should have received a copy of the GNU General Public License 19along with this program; if not, write to the Free Software 20Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ 21 22/* 23SECTION 24 Sections 25 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. 30 31 Sections are supported in BFD in <<section.c>>. 32 33@menu 34@* Section Input:: 35@* Section Output:: 36@* typedef asection:: 37@* section prototypes:: 38@end menu 39 40INODE 41Section Input, Section Output, Sections, Sections 42SUBSECTION 43 Section input 44 45 When a BFD is opened for reading, the section structures are 46 created and attached to the BFD. 47 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>>. 51 52 Names need not be unique; for example a COFF file may have several 53 sections named <<.data>>. 54 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 61 common storage. 62 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 71 relocations. 72 73INODE 74Section Output, typedef asection, Section Input, Sections 75 76SUBSECTION 77 Section output 78 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>>. 83 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.) 90 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. 98 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: 103 104| section name "A" 105| output_offset 0x00 106| size 0x20 107| output_section -----------> section name "O" 108| | vma 0x100 109| section name "B" | size 0x123 110| output_offset 0x20 | 111| size 0x103 | 112| output_section --------| 113 114SUBSECTION 115 Link orders 116 117 The data within a section is stored in a @dfn{link_order}. 118 These are much like the fixups in <<gas>>. The link_order 119 abstraction allows a section to grow and shrink within itself. 120 121 A link_order knows how big it is, and which is the next 122 link_order and where the raw data for it is; it also points to 123 a list of relocations which apply to it. 124 125 The link_order is used by the linker to perform relaxing on 126 final code. The compiler creates code which is as big as 127 necessary to make it work without relaxing, and the user can 128 select whether to relax. Sometimes relaxing takes a lot of 129 time. The linker runs around the relocations to see if any 130 are attached to data which can be shrunk, if so it does it on 131 a link_order by link_order basis. 132 133*/ 134 135#include "bfd.h" 136#include "sysdep.h" 137#include "libbfd.h" 138#include "bfdlink.h" 139 140/* 141DOCDD 142INODE 143typedef asection, section prototypes, Section Output, Sections 144SUBSECTION 145 typedef asection 146 147 Here is the section structure: 148 149CODE_FRAGMENT 150. 151.{* This structure is used for a comdat section, as in PE. A comdat 152. section is associated with a particular symbol. When the linker 153. sees a comdat section, it keeps only one of the sections with a 154. given name and associated with a given symbol. *} 155. 156.struct bfd_comdat_info 157.{ 158. {* The name of the symbol associated with a comdat section. *} 159. const char *name; 160. 161. {* The local symbol table index of the symbol associated with a 162. comdat section. This is only meaningful to the object file format 163. specific code; it is not an index into the list returned by 164. bfd_canonicalize_symtab. *} 165. long symbol; 166.}; 167. 168.typedef struct sec 169.{ 170. {* The name of the section; the name isn't a copy, the pointer is 171. the same as that passed to bfd_make_section. *} 172. 173. const char *name; 174. 175. {* A unique sequence number. *} 176. 177. int id; 178. 179. {* Which section is it; 0..nth. *} 180. 181. int index; 182. 183. {* The next section in the list belonging to the BFD, or NULL. *} 184. 185. struct sec *next; 186. 187. {* The field flags contains attributes of the section. Some 188. flags are read in from the object file, and some are 189. synthesized from other information. *} 190. 191. flagword flags; 192. 193.#define SEC_NO_FLAGS 0x000 194. 195. {* Tells the OS to allocate space for this section when loading. 196. This is clear for a section containing debug information only. *} 197.#define SEC_ALLOC 0x001 198. 199. {* Tells the OS to load the section from the file when loading. 200. This is clear for a .bss section. *} 201.#define SEC_LOAD 0x002 202. 203. {* The section contains data still to be relocated, so there is 204. some relocation information too. *} 205.#define SEC_RELOC 0x004 206. 207.#if 0 {* Obsolete ? *} 208.#define SEC_BALIGN 0x008 209.#endif 210. 211. {* A signal to the OS that the section contains read only data. *} 212.#define SEC_READONLY 0x010 213. 214. {* The section contains code only. *} 215.#define SEC_CODE 0x020 216. 217. {* The section contains data only. *} 218.#define SEC_DATA 0x040 219. 220. {* The section will reside in ROM. *} 221.#define SEC_ROM 0x080 222. 223. {* The section contains constructor information. This section 224. type is used by the linker to create lists of constructors and 225. destructors used by <<g++>>. When a back end sees a symbol 226. which should be used in a constructor list, it creates a new 227. section for the type of name (e.g., <<__CTOR_LIST__>>), attaches 228. the symbol to it, and builds a relocation. To build the lists 229. of constructors, all the linker has to do is catenate all the 230. sections called <<__CTOR_LIST__>> and relocate the data 231. contained within - exactly the operations it would peform on 232. standard data. *} 233.#define SEC_CONSTRUCTOR 0x100 234. 235. {* The section is a constructor, and should be placed at the 236. end of the text, data, or bss section(?). *} 237.#define SEC_CONSTRUCTOR_TEXT 0x1100 238.#define SEC_CONSTRUCTOR_DATA 0x2100 239.#define SEC_CONSTRUCTOR_BSS 0x3100 240. 241. {* The section has contents - a data section could be 242. <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>; a debug section could be 243. <<SEC_HAS_CONTENTS>> *} 244.#define SEC_HAS_CONTENTS 0x200 245. 246. {* An instruction to the linker to not output the section 247. even if it has information which would normally be written. *} 248.#define SEC_NEVER_LOAD 0x400 249. 250. {* The section is a COFF shared library section. This flag is 251. only for the linker. If this type of section appears in 252. the input file, the linker must copy it to the output file 253. without changing the vma or size. FIXME: Although this 254. was originally intended to be general, it really is COFF 255. specific (and the flag was renamed to indicate this). It 256. might be cleaner to have some more general mechanism to 257. allow the back end to control what the linker does with 258. sections. *} 259.#define SEC_COFF_SHARED_LIBRARY 0x800 260. 261. {* The section has GOT references. This flag is only for the 262. linker, and is currently only used by the elf32-hppa back end. 263. It will be set if global offset table references were detected 264. in this section, which indicate to the linker that the section 265. contains PIC code, and must be handled specially when doing a 266. static link. *} 267.#define SEC_HAS_GOT_REF 0x4000 268. 269. {* The section contains common symbols (symbols may be defined 270. multiple times, the value of a symbol is the amount of 271. space it requires, and the largest symbol value is the one 272. used). Most targets have exactly one of these (which we 273. translate to bfd_com_section_ptr), but ECOFF has two. *} 274.#define SEC_IS_COMMON 0x8000 275. 276. {* The section contains only debugging information. For 277. example, this is set for ELF .debug and .stab sections. 278. strip tests this flag to see if a section can be 279. discarded. *} 280.#define SEC_DEBUGGING 0x10000 281. 282. {* The contents of this section are held in memory pointed to 283. by the contents field. This is checked by bfd_get_section_contents, 284. and the data is retrieved from memory if appropriate. *} 285.#define SEC_IN_MEMORY 0x20000 286. 287. {* The contents of this section are to be excluded by the 288. linker for executable and shared objects unless those 289. objects are to be further relocated. *} 290.#define SEC_EXCLUDE 0x40000 291. 292. {* The contents of this section are to be sorted by the 293. based on the address specified in the associated symbol 294. table. *} 295.#define SEC_SORT_ENTRIES 0x80000 296. 297. {* When linking, duplicate sections of the same name should be 298. discarded, rather than being combined into a single section as 299. is usually done. This is similar to how common symbols are 300. handled. See SEC_LINK_DUPLICATES below. *} 301.#define SEC_LINK_ONCE 0x100000 302. 303. {* If SEC_LINK_ONCE is set, this bitfield describes how the linker 304. should handle duplicate sections. *} 305.#define SEC_LINK_DUPLICATES 0x600000 306. 307. {* This value for SEC_LINK_DUPLICATES means that duplicate 308. sections with the same name should simply be discarded. *} 309.#define SEC_LINK_DUPLICATES_DISCARD 0x0 310. 311. {* This value for SEC_LINK_DUPLICATES means that the linker 312. should warn if there are any duplicate sections, although 313. it should still only link one copy. *} 314.#define SEC_LINK_DUPLICATES_ONE_ONLY 0x200000 315. 316. {* This value for SEC_LINK_DUPLICATES means that the linker 317. should warn if any duplicate sections are a different size. *} 318.#define SEC_LINK_DUPLICATES_SAME_SIZE 0x400000 319. 320. {* This value for SEC_LINK_DUPLICATES means that the linker 321. should warn if any duplicate sections contain different 322. contents. *} 323.#define SEC_LINK_DUPLICATES_SAME_CONTENTS 0x600000 324. 325. {* This section was created by the linker as part of dynamic 326. relocation or other arcane processing. It is skipped when 327. going through the first-pass output, trusting that someone 328. else up the line will take care of it later. *} 329.#define SEC_LINKER_CREATED 0x800000 330. 331. {* This section should not be subject to garbage collection. *} 332.#define SEC_KEEP 0x1000000 333. 334. {* This section contains "short" data, and should be placed 335. "near" the GP. *} 336.#define SEC_SMALL_DATA 0x2000000 337. 338. {* This section contains data which may be shared with other 339. executables or shared objects. *} 340.#define SEC_SHARED 0x4000000 341. 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, it 345. should be aligned on a page boundary. *} 346.#define SEC_BLOCK 0x8000000 347. 348. {* Conditionally link this section; do not link if there are no 349. references found to any symbol in the section. *} 350.#define SEC_CLINK 0x10000000 351. 352. {* End of section flags. *} 353. 354. {* Some internal packed boolean fields. *} 355. 356. {* See the vma field. *} 357. unsigned int user_set_vma : 1; 358. 359. {* Whether relocations have been processed. *} 360. unsigned int reloc_done : 1; 361. 362. {* A mark flag used by some of the linker backends. *} 363. unsigned int linker_mark : 1; 364. 365. {* A mark flag used by some linker backends for garbage collection. *} 366. unsigned int gc_mark : 1; 367. 368. {* Used by the ELF code to mark sections which have been allocated to segments. *} 369. unsigned int segment_mark : 1; 370. 371. {* End of internal packed boolean fields. *} 372. 373. {* The virtual memory address of the section - where it will be 374. at run time. The symbols are relocated against this. The 375. user_set_vma flag is maintained by bfd; if it's not set, the 376. backend can assign addresses (for example, in <<a.out>>, where 377. the default address for <<.data>> is dependent on the specific 378. target and various flags). *} 379. 380. bfd_vma vma; 381. 382. {* The load address of the section - where it would be in a 383. rom image; really only used for writing section header 384. information. *} 385. 386. bfd_vma lma; 387. 388. {* The size of the section in octets, as it will be output. 389. Contains a value even if the section has no contents (e.g., the 390. size of <<.bss>>). This will be filled in after relocation. *} 391. 392. bfd_size_type _cooked_size; 393. 394. {* The original size on disk of the section, in octets. Normally this 395. value is the same as the size, but if some relaxing has 396. been done, then this value will be bigger. *} 397. 398. bfd_size_type _raw_size; 399. 400. {* If this section is going to be output, then this value is the 401. offset in *bytes* into the output section of the first byte in the 402. input section (byte ==> smallest addressable unit on the 403. target). In most cases, if this was going to start at the 404. 100th octet (8-bit quantity) in the output section, this value 405. would be 100. However, if the target byte size is 16 bits 406. (bfd_octets_per_byte is "2"), this value would be 50. *} 407. 408. bfd_vma output_offset; 409. 410. {* The output section through which to map on output. *} 411. 412. struct sec *output_section; 413. 414. {* The alignment requirement of the section, as an exponent of 2 - 415. e.g., 3 aligns to 2^3 (or 8). *} 416. 417. unsigned int alignment_power; 418. 419. {* If an input section, a pointer to a vector of relocation 420. records for the data in this section. *} 421. 422. struct reloc_cache_entry *relocation; 423. 424. {* If an output section, a pointer to a vector of pointers to 425. relocation records for the data in this section. *} 426. 427. struct reloc_cache_entry **orelocation; 428. 429. {* The number of relocation records in one of the above *} 430. 431. unsigned reloc_count; 432. 433. {* Information below is back end specific - and not always used 434. or updated. *} 435. 436. {* File position of section data. *} 437. 438. file_ptr filepos; 439. 440. {* File position of relocation info. *} 441. 442. file_ptr rel_filepos; 443. 444. {* File position of line data. *} 445. 446. file_ptr line_filepos; 447. 448. {* Pointer to data for applications. *} 449. 450. PTR userdata; 451. 452. {* If the SEC_IN_MEMORY flag is set, this points to the actual 453. contents. *} 454. unsigned char *contents; 455. 456. {* Attached line number information. *} 457. 458. alent *lineno; 459. 460. {* Number of line number records. *} 461. 462. unsigned int lineno_count; 463. 464. {* Optional information about a COMDAT entry; NULL if not COMDAT. *} 465. 466. struct bfd_comdat_info *comdat; 467. 468. {* Points to the kept section if this section is a link-once section, 469. and is discarded. *} 470. struct sec *kept_section; 471. 472. {* When a section is being output, this value changes as more 473. linenumbers are written out. *} 474. 475. file_ptr moving_line_filepos; 476. 477. {* What the section number is in the target world. *} 478. 479. int target_index; 480. 481. PTR used_by_bfd; 482. 483. {* If this is a constructor section then here is a list of the 484. relocations created to relocate items within it. *} 485. 486. struct relent_chain *constructor_chain; 487. 488. {* The BFD which owns the section. *} 489. 490. bfd *owner; 491. 492. {* A symbol which points at this section only *} 493. struct symbol_cache_entry *symbol; 494. struct symbol_cache_entry **symbol_ptr_ptr; 495. 496. struct bfd_link_order *link_order_head; 497. struct bfd_link_order *link_order_tail; 498.} asection ; 499. 500.{* These sections are global, and are managed by BFD. The application 501. and target back end are not permitted to change the values in 502. these sections. New code should use the section_ptr macros rather 503. than referring directly to the const sections. The const sections 504. may eventually vanish. *} 505.#define BFD_ABS_SECTION_NAME "*ABS*" 506.#define BFD_UND_SECTION_NAME "*UND*" 507.#define BFD_COM_SECTION_NAME "*COM*" 508.#define BFD_IND_SECTION_NAME "*IND*" 509. 510.{* the absolute section *} 511.extern const asection bfd_abs_section; 512.#define bfd_abs_section_ptr ((asection *) &bfd_abs_section) 513.#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr) 514.{* Pointer to the undefined section *} 515.extern const asection bfd_und_section; 516.#define bfd_und_section_ptr ((asection *) &bfd_und_section) 517.#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr) 518.{* Pointer to the common section *} 519.extern const asection bfd_com_section; 520.#define bfd_com_section_ptr ((asection *) &bfd_com_section) 521.{* Pointer to the indirect section *} 522.extern const asection bfd_ind_section; 523.#define bfd_ind_section_ptr ((asection *) &bfd_ind_section) 524.#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr) 525. 526.extern const struct symbol_cache_entry * const bfd_abs_symbol; 527.extern const struct symbol_cache_entry * const bfd_com_symbol; 528.extern const struct symbol_cache_entry * const bfd_und_symbol; 529.extern const struct symbol_cache_entry * const bfd_ind_symbol; 530.#define bfd_get_section_size_before_reloc(section) \ 531. ((section)->reloc_done ? (abort (), (bfd_size_type) 1) \ 532. : (section)->_raw_size) 533.#define bfd_get_section_size_after_reloc(section) \ 534. ((section)->reloc_done ? (section)->_cooked_size \ 535. : (abort (), (bfd_size_type) 1)) 536*/ 537 538/* We use a macro to initialize the static asymbol structures because 539 traditional C does not permit us to initialize a union member while 540 gcc warns if we don't initialize it. */ 541 /* the_bfd, name, value, attr, section [, udata] */ 542#ifdef __STDC__ 543#define GLOBAL_SYM_INIT(NAME, SECTION) \ 544 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION, { 0 }} 545#else 546#define GLOBAL_SYM_INIT(NAME, SECTION) \ 547 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION } 548#endif 549 550/* These symbols are global, not specific to any BFD. Therefore, anything 551 that tries to change them is broken, and should be repaired. */ 552 553static const asymbol global_syms[] = 554{ 555 GLOBAL_SYM_INIT (BFD_COM_SECTION_NAME, &bfd_com_section), 556 GLOBAL_SYM_INIT (BFD_UND_SECTION_NAME, &bfd_und_section), 557 GLOBAL_SYM_INIT (BFD_ABS_SECTION_NAME, &bfd_abs_section), 558 GLOBAL_SYM_INIT (BFD_IND_SECTION_NAME, &bfd_ind_section) 559}; 560 561#define STD_SECTION(SEC, FLAGS, SYM, NAME, IDX) \ 562 const asymbol * const SYM = (asymbol *) &global_syms[IDX]; \ 563 const asection SEC = \ 564 /* name, id, index, next, flags, user_set_vma, reloc_done, */ \ 565 { NAME, IDX, 0, NULL, FLAGS, 0, 0, \ 566 \ 567 /* linker_mark, gc_mark, segment_mark, vma, lma, _cooked_size, */ \ 568 0, 1, 0, 0, 0, 0, \ 569 \ 570 /* _raw_size, output_offset, output_section, alignment_power, */ \ 571 0, 0, (struct sec *) &SEC, 0, \ 572 \ 573 /* relocation, orelocation, reloc_count, filepos, rel_filepos, */ \ 574 NULL, NULL, 0, 0, 0, \ 575 \ 576 /* line_filepos, userdata, contents, lineno, lineno_count, */ \ 577 0, NULL, NULL, NULL, 0, \ 578 \ 579 /* comdat, kept_section, moving_line_filepos, target_index, */ \ 580 NULL, NULL, 0, 0, \ 581 \ 582 /* used_by_bfd, constructor_chain, owner, */ \ 583 NULL, NULL, NULL, \ 584 \ 585 /* symbol, */ \ 586 (struct symbol_cache_entry *) &global_syms[IDX], \ 587 \ 588 /* symbol_ptr_ptr, */ \ 589 (struct symbol_cache_entry **) &SYM, \ 590 \ 591 /* link_order_head, link_order_tail */ \ 592 NULL, NULL \ 593 } 594 595STD_SECTION (bfd_com_section, SEC_IS_COMMON, bfd_com_symbol, 596 BFD_COM_SECTION_NAME, 0); 597STD_SECTION (bfd_und_section, 0, bfd_und_symbol, BFD_UND_SECTION_NAME, 1); 598STD_SECTION (bfd_abs_section, 0, bfd_abs_symbol, BFD_ABS_SECTION_NAME, 2); 599STD_SECTION (bfd_ind_section, 0, bfd_ind_symbol, BFD_IND_SECTION_NAME, 3); 600#undef STD_SECTION 601 602/* 603DOCDD 604INODE 605section prototypes, , typedef asection, Sections 606SUBSECTION 607 Section prototypes 608 609These are the functions exported by the section handling part of BFD. 610*/ 611 612/* 613FUNCTION 614 bfd_get_section_by_name 615 616SYNOPSIS 617 asection *bfd_get_section_by_name(bfd *abfd, const char *name); 618 619DESCRIPTION 620 Run through @var{abfd} and return the one of the 621 <<asection>>s whose name matches @var{name}, otherwise <<NULL>>. 622 @xref{Sections}, for more information. 623 624 This should only be used in special cases; the normal way to process 625 all sections of a given name is to use <<bfd_map_over_sections>> and 626 <<strcmp>> on the name (or better yet, base it on the section flags 627 or something else) for each section. 628*/ 629 630asection * 631bfd_get_section_by_name (abfd, name) 632 bfd *abfd; 633 const char *name; 634{ 635 asection *sect; 636 637 for (sect = abfd->sections; sect != NULL; sect = sect->next) 638 if (!strcmp (sect->name, name)) 639 return sect; 640 return NULL; 641} 642 643/* 644FUNCTION 645 bfd_get_unique_section_name 646 647SYNOPSIS 648 char *bfd_get_unique_section_name(bfd *abfd, 649 const char *templat, 650 int *count); 651 652DESCRIPTION 653 Invent a section name that is unique in @var{abfd} by tacking 654 a dot and a digit suffix onto the original @var{templat}. If 655 @var{count} is non-NULL, then it specifies the first number 656 tried as a suffix to generate a unique name. The value 657 pointed to by @var{count} will be incremented in this case. 658*/ 659 660char * 661bfd_get_unique_section_name (abfd, templat, count) 662 bfd *abfd; 663 const char *templat; 664 int *count; 665{ 666 int num; 667 unsigned int len; 668 char *sname; 669 670 len = strlen (templat); 671 sname = bfd_malloc (len + 8); 672 if (sname == NULL) 673 return NULL; 674 strcpy (sname, templat); 675 num = 1; 676 if (count != NULL) 677 num = *count; 678 679 do 680 { 681 /* If we have a million sections, something is badly wrong. */ 682 if (num > 999999) 683 abort (); 684 sprintf (sname + len, ".%d", num++); 685 } 686 while (bfd_get_section_by_name (abfd, sname) != NULL); 687 688 if (count != NULL) 689 *count = num; 690 return sname; 691} 692 693/* 694FUNCTION 695 bfd_make_section_old_way 696 697SYNOPSIS 698 asection *bfd_make_section_old_way(bfd *abfd, const char *name); 699 700DESCRIPTION 701 Create a new empty section called @var{name} 702 and attach it to the end of the chain of sections for the 703 BFD @var{abfd}. An attempt to create a section with a name which 704 is already in use returns its pointer without changing the 705 section chain. 706 707 It has the funny name since this is the way it used to be 708 before it was rewritten.... 709 710 Possible errors are: 711 o <<bfd_error_invalid_operation>> - 712 If output has already started for this BFD. 713 o <<bfd_error_no_memory>> - 714 If memory allocation fails. 715 716*/ 717 718asection * 719bfd_make_section_old_way (abfd, name) 720 bfd *abfd; 721 const char *name; 722{ 723 asection *sec = bfd_get_section_by_name (abfd, name); 724 if (sec == (asection *) NULL) 725 { 726 sec = bfd_make_section (abfd, name); 727 } 728 return sec; 729} 730 731/* 732FUNCTION 733 bfd_make_section_anyway 734 735SYNOPSIS 736 asection *bfd_make_section_anyway(bfd *abfd, const char *name); 737 738DESCRIPTION 739 Create a new empty section called @var{name} and attach it to the end of 740 the chain of sections for @var{abfd}. Create a new section even if there 741 is already a section with that name. 742 743 Return <<NULL>> and set <<bfd_error>> on error; possible errors are: 744 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}. 745 o <<bfd_error_no_memory>> - If memory allocation fails. 746*/ 747 748sec_ptr 749bfd_make_section_anyway (abfd, name) 750 bfd *abfd; 751 const char *name; 752{ 753 static int section_id = 0x10; /* id 0 to 3 used by STD_SECTION. */ 754 asection *newsect; 755 asection **prev = &abfd->sections; 756 asection *sect = abfd->sections; 757 758 if (abfd->output_has_begun) 759 { 760 bfd_set_error (bfd_error_invalid_operation); 761 return NULL; 762 } 763 764 while (sect) 765 { 766 prev = §->next; 767 sect = sect->next; 768 } 769 770 newsect = (asection *) bfd_zalloc (abfd, sizeof (asection)); 771 if (newsect == NULL) 772 return NULL; 773 774 newsect->name = name; 775 newsect->id = section_id++; 776 newsect->index = abfd->section_count++; 777 newsect->flags = SEC_NO_FLAGS; 778 779 newsect->userdata = NULL; 780 newsect->contents = NULL; 781 newsect->next = (asection *) NULL; 782 newsect->relocation = (arelent *) NULL; 783 newsect->reloc_count = 0; 784 newsect->line_filepos = 0; 785 newsect->owner = abfd; 786 newsect->comdat = NULL; 787 newsect->kept_section = NULL; 788 789 /* Create a symbol whos only job is to point to this section. This is 790 useful for things like relocs which are relative to the base of a 791 section. */ 792 newsect->symbol = bfd_make_empty_symbol (abfd); 793 if (newsect->symbol == NULL) 794 { 795 bfd_release (abfd, newsect); 796 return NULL; 797 } 798 newsect->symbol->name = name; 799 newsect->symbol->value = 0; 800 newsect->symbol->section = newsect; 801 newsect->symbol->flags = BSF_SECTION_SYM; 802 803 newsect->symbol_ptr_ptr = &newsect->symbol; 804 805 if (BFD_SEND (abfd, _new_section_hook, (abfd, newsect)) != true) 806 { 807 bfd_release (abfd, newsect); 808 return NULL; 809 } 810 811 *prev = newsect; 812 return newsect; 813} 814 815/* 816FUNCTION 817 bfd_make_section 818 819SYNOPSIS 820 asection *bfd_make_section(bfd *, const char *name); 821 822DESCRIPTION 823 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling 824 bfd_set_error ()) without changing the section chain if there is already a 825 section named @var{name}. If there is an error, return <<NULL>> and set 826 <<bfd_error>>. 827*/ 828 829asection * 830bfd_make_section (abfd, name) 831 bfd *abfd; 832 const char *name; 833{ 834 asection *sect = abfd->sections; 835 836 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0) 837 { 838 return bfd_abs_section_ptr; 839 } 840 if (strcmp (name, BFD_COM_SECTION_NAME) == 0) 841 { 842 return bfd_com_section_ptr; 843 } 844 if (strcmp (name, BFD_UND_SECTION_NAME) == 0) 845 { 846 return bfd_und_section_ptr; 847 } 848 849 if (strcmp (name, BFD_IND_SECTION_NAME) == 0) 850 { 851 return bfd_ind_section_ptr; 852 } 853 854 while (sect) 855 { 856 if (!strcmp (sect->name, name)) 857 return NULL; 858 sect = sect->next; 859 } 860 861 /* The name is not already used; go ahead and make a new section. */ 862 return bfd_make_section_anyway (abfd, name); 863} 864 865/* 866FUNCTION 867 bfd_set_section_flags 868 869SYNOPSIS 870 boolean bfd_set_section_flags(bfd *abfd, asection *sec, flagword flags); 871 872DESCRIPTION 873 Set the attributes of the section @var{sec} in the BFD 874 @var{abfd} to the value @var{flags}. Return <<true>> on success, 875 <<false>> on error. Possible error returns are: 876 877 o <<bfd_error_invalid_operation>> - 878 The section cannot have one or more of the attributes 879 requested. For example, a .bss section in <<a.out>> may not 880 have the <<SEC_HAS_CONTENTS>> field set. 881 882*/ 883 884/*ARGSUSED*/ 885boolean 886bfd_set_section_flags (abfd, section, flags) 887 bfd *abfd ATTRIBUTE_UNUSED; 888 sec_ptr section; 889 flagword flags; 890{ 891#if 0 892 /* If you try to copy a text section from an input file (where it 893 has the SEC_CODE flag set) to an output file, this loses big if 894 the bfd_applicable_section_flags (abfd) doesn't have the SEC_CODE 895 set - which it doesn't, at least not for a.out. FIXME */ 896 897 if ((flags & bfd_applicable_section_flags (abfd)) != flags) 898 { 899 bfd_set_error (bfd_error_invalid_operation); 900 return false; 901 } 902#endif 903 904 section->flags = flags; 905 return true; 906} 907 908/* 909FUNCTION 910 bfd_map_over_sections 911 912SYNOPSIS 913 void bfd_map_over_sections(bfd *abfd, 914 void (*func) (bfd *abfd, 915 asection *sect, 916 PTR obj), 917 PTR obj); 918 919DESCRIPTION 920 Call the provided function @var{func} for each section 921 attached to the BFD @var{abfd}, passing @var{obj} as an 922 argument. The function will be called as if by 923 924| func(abfd, the_section, obj); 925 926 This is the prefered method for iterating over sections; an 927 alternative would be to use a loop: 928 929| section *p; 930| for (p = abfd->sections; p != NULL; p = p->next) 931| func(abfd, p, ...) 932 933*/ 934 935/*VARARGS2*/ 936void 937bfd_map_over_sections (abfd, operation, user_storage) 938 bfd *abfd; 939 void (*operation) PARAMS ((bfd * abfd, asection * sect, PTR obj)); 940 PTR user_storage; 941{ 942 asection *sect; 943 unsigned int i = 0; 944 945 for (sect = abfd->sections; sect != NULL; i++, sect = sect->next) 946 (*operation) (abfd, sect, user_storage); 947 948 if (i != abfd->section_count) /* Debugging */ 949 abort (); 950} 951 952/* 953FUNCTION 954 bfd_set_section_size 955 956SYNOPSIS 957 boolean bfd_set_section_size(bfd *abfd, asection *sec, bfd_size_type val); 958 959DESCRIPTION 960 Set @var{sec} to the size @var{val}. If the operation is 961 ok, then <<true>> is returned, else <<false>>. 962 963 Possible error returns: 964 o <<bfd_error_invalid_operation>> - 965 Writing has started to the BFD, so setting the size is invalid. 966 967*/ 968 969boolean 970bfd_set_section_size (abfd, ptr, val) 971 bfd *abfd; 972 sec_ptr ptr; 973 bfd_size_type val; 974{ 975 /* Once you've started writing to any section you cannot create or change 976 the size of any others. */ 977 978 if (abfd->output_has_begun) 979 { 980 bfd_set_error (bfd_error_invalid_operation); 981 return false; 982 } 983 984 ptr->_cooked_size = val; 985 ptr->_raw_size = val; 986 987 return true; 988} 989 990/* 991FUNCTION 992 bfd_set_section_contents 993 994SYNOPSIS 995 boolean bfd_set_section_contents 996 (bfd *abfd, 997 asection *section, 998 PTR data, 999 file_ptr offset, 1000 bfd_size_type count); 1001 1002DESCRIPTION 1003 Sets the contents of the section @var{section} in BFD 1004 @var{abfd} to the data starting in memory at @var{data}. The 1005 data is written to the output section starting at offset 1006 @var{offset} for @var{count} octets. 1007 1008 Normally <<true>> is returned, else <<false>>. Possible error 1009 returns are: 1010 o <<bfd_error_no_contents>> - 1011 The output section does not have the <<SEC_HAS_CONTENTS>> 1012 attribute, so nothing can be written to it. 1013 o and some more too 1014 1015 This routine is front end to the back end function 1016 <<_bfd_set_section_contents>>. 1017 1018*/ 1019 1020#define bfd_get_section_size_now(abfd,sec) \ 1021(sec->reloc_done \ 1022 ? bfd_get_section_size_after_reloc (sec) \ 1023 : bfd_get_section_size_before_reloc (sec)) 1024 1025boolean 1026bfd_set_section_contents (abfd, section, location, offset, count) 1027 bfd *abfd; 1028 sec_ptr section; 1029 PTR location; 1030 file_ptr offset; 1031 bfd_size_type count; 1032{ 1033 bfd_size_type sz; 1034 1035 if (!(bfd_get_section_flags (abfd, section) & SEC_HAS_CONTENTS)) 1036 { 1037 bfd_set_error (bfd_error_no_contents); 1038 return (false); 1039 } 1040 1041 if (offset < 0) 1042 { 1043 bad_val: 1044 bfd_set_error (bfd_error_bad_value); 1045 return false; 1046 } 1047 sz = bfd_get_section_size_now (abfd, section); 1048 if ((bfd_size_type) offset > sz 1049 || count > sz 1050 || offset + count > sz) 1051 goto bad_val; 1052 1053 switch (abfd->direction) 1054 { 1055 case read_direction: 1056 case no_direction: 1057 bfd_set_error (bfd_error_invalid_operation); 1058 return false; 1059 1060 case write_direction: 1061 break; 1062 1063 case both_direction: 1064 /* File is opened for update. `output_has_begun' some time ago when 1065 the file was created. Do not recompute sections sizes or alignments 1066 in _bfd_set_section_content. */ 1067 abfd->output_has_begun = true; 1068 break; 1069 } 1070 1071 /* Record a copy of the data in memory if desired. */ 1072 if (section->contents 1073 && location != section->contents + offset) 1074 memcpy (section->contents + offset, location, count); 1075 1076 if (BFD_SEND (abfd, _bfd_set_section_contents, 1077 (abfd, section, location, offset, count))) 1078 { 1079 abfd->output_has_begun = true; 1080 return true; 1081 } 1082 1083 return false; 1084} 1085 1086/* 1087FUNCTION 1088 bfd_get_section_contents 1089 1090SYNOPSIS 1091 boolean bfd_get_section_contents 1092 (bfd *abfd, asection *section, PTR location, 1093 file_ptr offset, bfd_size_type count); 1094 1095DESCRIPTION 1096 Read data from @var{section} in BFD @var{abfd} 1097 into memory starting at @var{location}. The data is read at an 1098 offset of @var{offset} from the start of the input section, 1099 and is read for @var{count} bytes. 1100 1101 If the contents of a constructor with the <<SEC_CONSTRUCTOR>> 1102 flag set are requested or if the section does not have the 1103 <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled 1104 with zeroes. If no errors occur, <<true>> is returned, else 1105 <<false>>. 1106 1107*/ 1108boolean 1109bfd_get_section_contents (abfd, section, location, offset, count) 1110 bfd *abfd; 1111 sec_ptr section; 1112 PTR location; 1113 file_ptr offset; 1114 bfd_size_type count; 1115{ 1116 bfd_size_type sz; 1117 1118 if (section->flags & SEC_CONSTRUCTOR) 1119 { 1120 memset (location, 0, (unsigned) count); 1121 return true; 1122 } 1123 1124 if (offset < 0) 1125 { 1126 bad_val: 1127 bfd_set_error (bfd_error_bad_value); 1128 return false; 1129 } 1130 /* Even if reloc_done is true, this function reads unrelocated 1131 contents, so we want the raw size. */ 1132 sz = section->_raw_size; 1133 if ((bfd_size_type) offset > sz || count > sz || offset + count > sz) 1134 goto bad_val; 1135 1136 if (count == 0) 1137 /* Don't bother. */ 1138 return true; 1139 1140 if ((section->flags & SEC_HAS_CONTENTS) == 0) 1141 { 1142 memset (location, 0, (unsigned) count); 1143 return true; 1144 } 1145 1146 if ((section->flags & SEC_IN_MEMORY) != 0) 1147 { 1148 memcpy (location, section->contents + offset, (size_t) count); 1149 return true; 1150 } 1151 1152 return BFD_SEND (abfd, _bfd_get_section_contents, 1153 (abfd, section, location, offset, count)); 1154} 1155 1156/* 1157FUNCTION 1158 bfd_copy_private_section_data 1159 1160SYNOPSIS 1161 boolean bfd_copy_private_section_data(bfd *ibfd, asection *isec, bfd *obfd, asection *osec); 1162 1163DESCRIPTION 1164 Copy private section information from @var{isec} in the BFD 1165 @var{ibfd} to the section @var{osec} in the BFD @var{obfd}. 1166 Return <<true>> on success, <<false>> on error. Possible error 1167 returns are: 1168 1169 o <<bfd_error_no_memory>> - 1170 Not enough memory exists to create private data for @var{osec}. 1171 1172.#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \ 1173. BFD_SEND (obfd, _bfd_copy_private_section_data, \ 1174. (ibfd, isection, obfd, osection)) 1175*/ 1176 1177/* 1178FUNCTION 1179 _bfd_strip_section_from_output 1180 1181SYNOPSIS 1182 void _bfd_strip_section_from_output 1183 (struct bfd_link_info *info, asection *section); 1184 1185DESCRIPTION 1186 Remove @var{section} from the output. If the output section 1187 becomes empty, remove it from the output bfd. @var{info} may 1188 be NULL; if it is not, it is used to decide whether the output 1189 section is empty. 1190*/ 1191void 1192_bfd_strip_section_from_output (info, s) 1193 struct bfd_link_info *info; 1194 asection *s; 1195{ 1196 asection **spp, *os; 1197 struct bfd_link_order *p, *pp; 1198 boolean keep_os; 1199 1200 /* Excise the input section from the link order. 1201 1202 FIXME: For all calls that I can see to this function, the link 1203 orders have not yet been set up. So why are we checking them? -- 1204 Ian */ 1205 os = s->output_section; 1206 for (p = os->link_order_head, pp = NULL; p != NULL; pp = p, p = p->next) 1207 if (p->type == bfd_indirect_link_order 1208 && p->u.indirect.section == s) 1209 { 1210 if (pp) 1211 pp->next = p->next; 1212 else 1213 os->link_order_head = p->next; 1214 if (!p->next) 1215 os->link_order_tail = pp; 1216 break; 1217 } 1218 1219 keep_os = os->link_order_head != NULL; 1220 1221 if (! keep_os && info != NULL) 1222 { 1223 bfd *abfd; 1224 for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link_next) 1225 { 1226 asection *is; 1227 for (is = abfd->sections; is != NULL; is = is->next) 1228 { 1229 if (is != s && is->output_section == os) 1230 break; 1231 } 1232 if (is != NULL) 1233 break; 1234 } 1235 if (abfd != NULL) 1236 keep_os = true; 1237 } 1238 1239 /* If the output section is empty, remove it too. Careful about sections 1240 that have been discarded in the link script -- they are mapped to 1241 bfd_abs_section, which has no owner. */ 1242 if (!keep_os && os->owner != NULL) 1243 { 1244 for (spp = &os->owner->sections; *spp; spp = &(*spp)->next) 1245 if (*spp == os) 1246 { 1247 *spp = os->next; 1248 os->owner->section_count--; 1249 break; 1250 } 1251 } 1252} 1253