section.c revision 89857
1/* Object file "section" support for the BFD library. 2 Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 3 2000, 2001, 2002 4 Free Software Foundation, Inc. 5 Written by Cygnus Support. 6 7This file is part of BFD, the Binary File Descriptor library. 8 9This program is free software; you can redistribute it and/or modify 10it under the terms of the GNU General Public License as published by 11the Free Software Foundation; either version 2 of the License, or 12(at your option) any later version. 13 14This program is distributed in the hope that it will be useful, 15but WITHOUT ANY WARRANTY; without even the implied warranty of 16MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17GNU General Public License for more details. 18 19You should have received a copy of the GNU General Public License 20along with this program; if not, write to the Free Software 21Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ 22 23/* 24SECTION 25 Sections 26 27 The raw data contained within a BFD is maintained through the 28 section abstraction. A single BFD may have any number of 29 sections. It keeps hold of them by pointing to the first; 30 each one points to the next in the list. 31 32 Sections are supported in BFD in <<section.c>>. 33 34@menu 35@* Section Input:: 36@* Section Output:: 37@* typedef asection:: 38@* section prototypes:: 39@end menu 40 41INODE 42Section Input, Section Output, Sections, Sections 43SUBSECTION 44 Section input 45 46 When a BFD is opened for reading, the section structures are 47 created and attached to the BFD. 48 49 Each section has a name which describes the section in the 50 outside world---for example, <<a.out>> would contain at least 51 three sections, called <<.text>>, <<.data>> and <<.bss>>. 52 53 Names need not be unique; for example a COFF file may have several 54 sections named <<.data>>. 55 56 Sometimes a BFD will contain more than the ``natural'' number of 57 sections. A back end may attach other sections containing 58 constructor data, or an application may add a section (using 59 <<bfd_make_section>>) to the sections attached to an already open 60 BFD. For example, the linker creates an extra section 61 <<COMMON>> for each input file's BFD to hold information about 62 common storage. 63 64 The raw data is not necessarily read in when 65 the section descriptor is created. Some targets may leave the 66 data in place until a <<bfd_get_section_contents>> call is 67 made. Other back ends may read in all the data at once. For 68 example, an S-record file has to be read once to determine the 69 size of the data. An IEEE-695 file doesn't contain raw data in 70 sections, but data and relocation expressions intermixed, so 71 the data area has to be parsed to get out the data and 72 relocations. 73 74INODE 75Section Output, typedef asection, Section Input, Sections 76 77SUBSECTION 78 Section output 79 80 To write a new object style BFD, the various sections to be 81 written have to be created. They are attached to the BFD in 82 the same way as input sections; data is written to the 83 sections using <<bfd_set_section_contents>>. 84 85 Any program that creates or combines sections (e.g., the assembler 86 and linker) must use the <<asection>> fields <<output_section>> and 87 <<output_offset>> to indicate the file sections to which each 88 section must be written. (If the section is being created from 89 scratch, <<output_section>> should probably point to the section 90 itself and <<output_offset>> should probably be zero.) 91 92 The data to be written comes from input sections attached 93 (via <<output_section>> pointers) to 94 the output sections. The output section structure can be 95 considered a filter for the input section: the output section 96 determines the vma of the output data and the name, but the 97 input section determines the offset into the output section of 98 the data to be written. 99 100 E.g., to create a section "O", starting at 0x100, 0x123 long, 101 containing two subsections, "A" at offset 0x0 (i.e., at vma 102 0x100) and "B" at offset 0x20 (i.e., at vma 0x120) the <<asection>> 103 structures would look like: 104 105| section name "A" 106| output_offset 0x00 107| size 0x20 108| output_section -----------> section name "O" 109| | vma 0x100 110| section name "B" | size 0x123 111| output_offset 0x20 | 112| size 0x103 | 113| output_section --------| 114 115SUBSECTION 116 Link orders 117 118 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. 121 122 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. 125 126 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. 133 134*/ 135 136#include "bfd.h" 137#include "sysdep.h" 138#include "libbfd.h" 139#include "bfdlink.h" 140 141/* 142DOCDD 143INODE 144typedef asection, section prototypes, Section Output, Sections 145SUBSECTION 146 typedef asection 147 148 Here is the section structure: 149 150CODE_FRAGMENT 151. 152.{* This structure is used for a comdat section, as in PE. A comdat 153. section is associated with a particular symbol. When the linker 154. sees a comdat section, it keeps only one of the sections with a 155. given name and associated with a given symbol. *} 156. 157.struct bfd_comdat_info 158.{ 159. {* The name of the symbol associated with a comdat section. *} 160. const char *name; 161. 162. {* The local symbol table index of the symbol associated with a 163. comdat section. This is only meaningful to the object file format 164. specific code; it is not an index into the list returned by 165. bfd_canonicalize_symtab. *} 166. long symbol; 167.}; 168. 169.typedef struct sec 170.{ 171. {* The name of the section; the name isn't a copy, the pointer is 172. the same as that passed to bfd_make_section. *} 173. 174. const char *name; 175. 176. {* A unique sequence number. *} 177. 178. int id; 179. 180. {* Which section in the bfd; 0..n-1 as sections are created in a bfd. *} 181. 182. int index; 183. 184. {* The next section in the list belonging to the BFD, or NULL. *} 185. 186. struct sec *next; 187. 188. {* The field flags contains attributes of the section. Some 189. flags are read in from the object file, and some are 190. synthesized from other information. *} 191. 192. flagword flags; 193. 194.#define SEC_NO_FLAGS 0x000 195. 196. {* Tells the OS to allocate space for this section when loading. 197. This is clear for a section containing debug information only. *} 198.#define SEC_ALLOC 0x001 199. 200. {* Tells the OS to load the section from the file when loading. 201. This is clear for a .bss section. *} 202.#define SEC_LOAD 0x002 203. 204. {* The section contains data still to be relocated, so there is 205. some relocation information too. *} 206.#define SEC_RELOC 0x004 207. 208. {* ELF reserves 4 processor specific bits and 8 operating system 209. specific bits in sh_flags; at present we can get away with just 210. one in communicating between the assembler and BFD, but this 211. isn't a good long-term solution. *} 212.#define SEC_ARCH_BIT_0 0x008 213. 214. {* A signal to the OS that the section contains read only data. *} 215.#define SEC_READONLY 0x010 216. 217. {* The section contains code only. *} 218.#define SEC_CODE 0x020 219. 220. {* The section contains data only. *} 221.#define SEC_DATA 0x040 222. 223. {* The section will reside in ROM. *} 224.#define SEC_ROM 0x080 225. 226. {* The section contains constructor information. This section 227. type is used by the linker to create lists of constructors and 228. destructors used by <<g++>>. When a back end sees a symbol 229. which should be used in a constructor list, it creates a new 230. section for the type of name (e.g., <<__CTOR_LIST__>>), attaches 231. the symbol to it, and builds a relocation. To build the lists 232. of constructors, all the linker has to do is catenate all the 233. sections called <<__CTOR_LIST__>> and relocate the data 234. contained within - exactly the operations it would peform on 235. standard data. *} 236.#define SEC_CONSTRUCTOR 0x100 237. 238. {* The section is a constructor, and should be placed at the 239. end of the text, data, or bss section(?). *} 240.#define SEC_CONSTRUCTOR_TEXT 0x1100 241.#define SEC_CONSTRUCTOR_DATA 0x2100 242.#define SEC_CONSTRUCTOR_BSS 0x3100 243. 244. {* The section has contents - a data section could be 245. <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>; a debug section could be 246. <<SEC_HAS_CONTENTS>> *} 247.#define SEC_HAS_CONTENTS 0x200 248. 249. {* An instruction to the linker to not output the section 250. even if it has information which would normally be written. *} 251.#define SEC_NEVER_LOAD 0x400 252. 253. {* The section is a COFF shared library section. This flag is 254. only for the linker. If this type of section appears in 255. the input file, the linker must copy it to the output file 256. without changing the vma or size. FIXME: Although this 257. was originally intended to be general, it really is COFF 258. specific (and the flag was renamed to indicate this). It 259. might be cleaner to have some more general mechanism to 260. allow the back end to control what the linker does with 261. sections. *} 262.#define SEC_COFF_SHARED_LIBRARY 0x800 263. 264. {* The section has GOT references. This flag is only for the 265. linker, and is currently only used by the elf32-hppa back end. 266. It will be set if global offset table references were detected 267. in this section, which indicate to the linker that the section 268. contains PIC code, and must be handled specially when doing a 269. static link. *} 270.#define SEC_HAS_GOT_REF 0x4000 271. 272. {* The section contains common symbols (symbols may be defined 273. multiple times, the value of a symbol is the amount of 274. space it requires, and the largest symbol value is the one 275. used). Most targets have exactly one of these (which we 276. translate to bfd_com_section_ptr), but ECOFF has two. *} 277.#define SEC_IS_COMMON 0x8000 278. 279. {* The section contains only debugging information. For 280. example, this is set for ELF .debug and .stab sections. 281. strip tests this flag to see if a section can be 282. discarded. *} 283.#define SEC_DEBUGGING 0x10000 284. 285. {* The contents of this section are held in memory pointed to 286. by the contents field. This is checked by bfd_get_section_contents, 287. and the data is retrieved from memory if appropriate. *} 288.#define SEC_IN_MEMORY 0x20000 289. 290. {* The contents of this section are to be excluded by the 291. linker for executable and shared objects unless those 292. objects are to be further relocated. *} 293.#define SEC_EXCLUDE 0x40000 294. 295. {* The contents of this section are to be sorted based on the sum of 296. the symbol and addend values specified by the associated relocation 297. entries. Entries without associated relocation entries will be 298. appended to the end of the section in an unspecified order. *} 299.#define SEC_SORT_ENTRIES 0x80000 300. 301. {* When linking, duplicate sections of the same name should be 302. discarded, rather than being combined into a single section as 303. is usually done. This is similar to how common symbols are 304. handled. See SEC_LINK_DUPLICATES below. *} 305.#define SEC_LINK_ONCE 0x100000 306. 307. {* If SEC_LINK_ONCE is set, this bitfield describes how the linker 308. should handle duplicate sections. *} 309.#define SEC_LINK_DUPLICATES 0x600000 310. 311. {* This value for SEC_LINK_DUPLICATES means that duplicate 312. sections with the same name should simply be discarded. *} 313.#define SEC_LINK_DUPLICATES_DISCARD 0x0 314. 315. {* This value for SEC_LINK_DUPLICATES means that the linker 316. should warn if there are any duplicate sections, although 317. it should still only link one copy. *} 318.#define SEC_LINK_DUPLICATES_ONE_ONLY 0x200000 319. 320. {* This value for SEC_LINK_DUPLICATES means that the linker 321. should warn if any duplicate sections are a different size. *} 322.#define SEC_LINK_DUPLICATES_SAME_SIZE 0x400000 323. 324. {* This value for SEC_LINK_DUPLICATES means that the linker 325. should warn if any duplicate sections contain different 326. contents. *} 327.#define SEC_LINK_DUPLICATES_SAME_CONTENTS 0x600000 328. 329. {* This section was created by the linker as part of dynamic 330. relocation or other arcane processing. It is skipped when 331. going through the first-pass output, trusting that someone 332. else up the line will take care of it later. *} 333.#define SEC_LINKER_CREATED 0x800000 334. 335. {* This section should not be subject to garbage collection. *} 336.#define SEC_KEEP 0x1000000 337. 338. {* This section contains "short" data, and should be placed 339. "near" the GP. *} 340.#define SEC_SMALL_DATA 0x2000000 341. 342. {* This section contains data which may be shared with other 343. executables or shared objects. *} 344.#define SEC_SHARED 0x4000000 345. 346. {* When a section with this flag is being linked, then if the size of 347. the input section is less than a page, it should not cross a page 348. boundary. If the size of the input section is one page or more, it 349. should be aligned on a page boundary. *} 350.#define SEC_BLOCK 0x8000000 351. 352. {* Conditionally link this section; do not link if there are no 353. references found to any symbol in the section. *} 354.#define SEC_CLINK 0x10000000 355. 356. {* Attempt to merge identical entities in the section. 357. Entity size is given in the entsize field. *} 358.#define SEC_MERGE 0x20000000 359. 360. {* If given with SEC_MERGE, entities to merge are zero terminated 361. strings where entsize specifies character size instead of fixed 362. size entries. *} 363.#define SEC_STRINGS 0x40000000 364. 365. {* This section contains data about section groups. *} 366.#define SEC_GROUP 0x80000000 367. 368. {* End of section flags. *} 369. 370. {* Some internal packed boolean fields. *} 371. 372. {* See the vma field. *} 373. unsigned int user_set_vma : 1; 374. 375. {* Whether relocations have been processed. *} 376. unsigned int reloc_done : 1; 377. 378. {* A mark flag used by some of the linker backends. *} 379. unsigned int linker_mark : 1; 380. 381. {* Another mark flag used by some of the linker backends. Set for 382. output sections that have an input section. *} 383. unsigned int linker_has_input : 1; 384. 385. {* A mark flag used by some linker backends for garbage collection. *} 386. unsigned int gc_mark : 1; 387. 388. {* Used by the ELF code to mark sections which have been allocated 389. to segments. *} 390. unsigned int segment_mark : 1; 391. 392. {* End of internal packed boolean fields. *} 393. 394. {* The virtual memory address of the section - where it will be 395. at run time. The symbols are relocated against this. The 396. user_set_vma flag is maintained by bfd; if it's not set, the 397. backend can assign addresses (for example, in <<a.out>>, where 398. the default address for <<.data>> is dependent on the specific 399. target and various flags). *} 400. 401. bfd_vma vma; 402. 403. {* The load address of the section - where it would be in a 404. rom image; really only used for writing section header 405. information. *} 406. 407. bfd_vma lma; 408. 409. {* The size of the section in octets, as it will be output. 410. Contains a value even if the section has no contents (e.g., the 411. size of <<.bss>>). This will be filled in after relocation. *} 412. 413. bfd_size_type _cooked_size; 414. 415. {* The original size on disk of the section, in octets. Normally this 416. value is the same as the size, but if some relaxing has 417. been done, then this value will be bigger. *} 418. 419. bfd_size_type _raw_size; 420. 421. {* If this section is going to be output, then this value is the 422. offset in *bytes* into the output section of the first byte in the 423. input section (byte ==> smallest addressable unit on the 424. target). In most cases, if this was going to start at the 425. 100th octet (8-bit quantity) in the output section, this value 426. would be 100. However, if the target byte size is 16 bits 427. (bfd_octets_per_byte is "2"), this value would be 50. *} 428. 429. bfd_vma output_offset; 430. 431. {* The output section through which to map on output. *} 432. 433. struct sec *output_section; 434. 435. {* The alignment requirement of the section, as an exponent of 2 - 436. e.g., 3 aligns to 2^3 (or 8). *} 437. 438. unsigned int alignment_power; 439. 440. {* If an input section, a pointer to a vector of relocation 441. records for the data in this section. *} 442. 443. struct reloc_cache_entry *relocation; 444. 445. {* If an output section, a pointer to a vector of pointers to 446. relocation records for the data in this section. *} 447. 448. struct reloc_cache_entry **orelocation; 449. 450. {* The number of relocation records in one of the above *} 451. 452. unsigned reloc_count; 453. 454. {* Information below is back end specific - and not always used 455. or updated. *} 456. 457. {* File position of section data. *} 458. 459. file_ptr filepos; 460. 461. {* File position of relocation info. *} 462. 463. file_ptr rel_filepos; 464. 465. {* File position of line data. *} 466. 467. file_ptr line_filepos; 468. 469. {* Pointer to data for applications. *} 470. 471. PTR userdata; 472. 473. {* If the SEC_IN_MEMORY flag is set, this points to the actual 474. contents. *} 475. unsigned char *contents; 476. 477. {* Attached line number information. *} 478. 479. alent *lineno; 480. 481. {* Number of line number records. *} 482. 483. unsigned int lineno_count; 484. 485. {* Entity size for merging purposes. *} 486. 487. unsigned int entsize; 488. 489. {* Optional information about a COMDAT entry; NULL if not COMDAT. *} 490. 491. struct bfd_comdat_info *comdat; 492. 493. {* When a section is being output, this value changes as more 494. linenumbers are written out. *} 495. 496. file_ptr moving_line_filepos; 497. 498. {* What the section number is in the target world. *} 499. 500. int target_index; 501. 502. PTR used_by_bfd; 503. 504. {* If this is a constructor section then here is a list of the 505. relocations created to relocate items within it. *} 506. 507. struct relent_chain *constructor_chain; 508. 509. {* The BFD which owns the section. *} 510. 511. bfd *owner; 512. 513. {* A symbol which points at this section only *} 514. struct symbol_cache_entry *symbol; 515. struct symbol_cache_entry **symbol_ptr_ptr; 516. 517. struct bfd_link_order *link_order_head; 518. struct bfd_link_order *link_order_tail; 519.} asection ; 520. 521.{* These sections are global, and are managed by BFD. The application 522. and target back end are not permitted to change the values in 523. these sections. New code should use the section_ptr macros rather 524. than referring directly to the const sections. The const sections 525. may eventually vanish. *} 526.#define BFD_ABS_SECTION_NAME "*ABS*" 527.#define BFD_UND_SECTION_NAME "*UND*" 528.#define BFD_COM_SECTION_NAME "*COM*" 529.#define BFD_IND_SECTION_NAME "*IND*" 530. 531.{* the absolute section *} 532.extern const asection bfd_abs_section; 533.#define bfd_abs_section_ptr ((asection *) &bfd_abs_section) 534.#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr) 535.{* Pointer to the undefined section *} 536.extern const asection bfd_und_section; 537.#define bfd_und_section_ptr ((asection *) &bfd_und_section) 538.#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr) 539.{* Pointer to the common section *} 540.extern const asection bfd_com_section; 541.#define bfd_com_section_ptr ((asection *) &bfd_com_section) 542.{* Pointer to the indirect section *} 543.extern const asection bfd_ind_section; 544.#define bfd_ind_section_ptr ((asection *) &bfd_ind_section) 545.#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr) 546. 547.#define bfd_is_const_section(SEC) \ 548. ( ((SEC) == bfd_abs_section_ptr) \ 549. || ((SEC) == bfd_und_section_ptr) \ 550. || ((SEC) == bfd_com_section_ptr) \ 551. || ((SEC) == bfd_ind_section_ptr)) 552. 553.extern const struct symbol_cache_entry * const bfd_abs_symbol; 554.extern const struct symbol_cache_entry * const bfd_com_symbol; 555.extern const struct symbol_cache_entry * const bfd_und_symbol; 556.extern const struct symbol_cache_entry * const bfd_ind_symbol; 557.#define bfd_get_section_size_before_reloc(section) \ 558. ((section)->reloc_done ? (abort (), (bfd_size_type) 1) \ 559. : (section)->_raw_size) 560.#define bfd_get_section_size_after_reloc(section) \ 561. ((section)->reloc_done ? (section)->_cooked_size \ 562. : (abort (), (bfd_size_type) 1)) 563. 564.{* Macros to handle insertion and deletion of a bfd's sections. These 565. only handle the list pointers, ie. do not adjust section_count, 566. target_index etc. *} 567.#define bfd_section_list_remove(ABFD, PS) \ 568. do \ 569. { \ 570. asection **_ps = PS; \ 571. asection *_s = *_ps; \ 572. *_ps = _s->next; \ 573. if (_s->next == NULL) \ 574. (ABFD)->section_tail = _ps; \ 575. } \ 576. while (0) 577.#define bfd_section_list_insert(ABFD, PS, S) \ 578. do \ 579. { \ 580. asection **_ps = PS; \ 581. asection *_s = S; \ 582. _s->next = *_ps; \ 583. *_ps = _s; \ 584. if (_s->next == NULL) \ 585. (ABFD)->section_tail = &_s->next; \ 586. } \ 587. while (0) 588. 589*/ 590 591/* We use a macro to initialize the static asymbol structures because 592 traditional C does not permit us to initialize a union member while 593 gcc warns if we don't initialize it. */ 594 /* the_bfd, name, value, attr, section [, udata] */ 595#ifdef __STDC__ 596#define GLOBAL_SYM_INIT(NAME, SECTION) \ 597 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION, { 0 }} 598#else 599#define GLOBAL_SYM_INIT(NAME, SECTION) \ 600 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION } 601#endif 602 603/* These symbols are global, not specific to any BFD. Therefore, anything 604 that tries to change them is broken, and should be repaired. */ 605 606static const asymbol global_syms[] = 607{ 608 GLOBAL_SYM_INIT (BFD_COM_SECTION_NAME, &bfd_com_section), 609 GLOBAL_SYM_INIT (BFD_UND_SECTION_NAME, &bfd_und_section), 610 GLOBAL_SYM_INIT (BFD_ABS_SECTION_NAME, &bfd_abs_section), 611 GLOBAL_SYM_INIT (BFD_IND_SECTION_NAME, &bfd_ind_section) 612}; 613 614#define STD_SECTION(SEC, FLAGS, SYM, NAME, IDX) \ 615 const asymbol * const SYM = (asymbol *) &global_syms[IDX]; \ 616 const asection SEC = \ 617 /* name, id, index, next, flags, user_set_vma, reloc_done, */ \ 618 { NAME, IDX, 0, NULL, FLAGS, 0, 0, \ 619 \ 620 /* linker_mark, linker_has_input, gc_mark, segment_mark, */ \ 621 0, 0, 1, 0, \ 622 \ 623 /* vma, lma, _cooked_size, _raw_size, */ \ 624 0, 0, 0, 0, \ 625 \ 626 /* output_offset, output_section, alignment_power, */ \ 627 0, (struct sec *) &SEC, 0, \ 628 \ 629 /* relocation, orelocation, reloc_count, filepos, rel_filepos, */ \ 630 NULL, NULL, 0, 0, 0, \ 631 \ 632 /* line_filepos, userdata, contents, lineno, lineno_count, */ \ 633 0, NULL, NULL, NULL, 0, \ 634 \ 635 /* entsize, comdat, moving_line_filepos, */ \ 636 0, NULL, 0, \ 637 \ 638 /* target_index, used_by_bfd, constructor_chain, owner, */ \ 639 0, NULL, NULL, NULL, \ 640 \ 641 /* symbol, */ \ 642 (struct symbol_cache_entry *) &global_syms[IDX], \ 643 \ 644 /* symbol_ptr_ptr, */ \ 645 (struct symbol_cache_entry **) &SYM, \ 646 \ 647 /* link_order_head, link_order_tail */ \ 648 NULL, NULL \ 649 } 650 651STD_SECTION (bfd_com_section, SEC_IS_COMMON, bfd_com_symbol, 652 BFD_COM_SECTION_NAME, 0); 653STD_SECTION (bfd_und_section, 0, bfd_und_symbol, BFD_UND_SECTION_NAME, 1); 654STD_SECTION (bfd_abs_section, 0, bfd_abs_symbol, BFD_ABS_SECTION_NAME, 2); 655STD_SECTION (bfd_ind_section, 0, bfd_ind_symbol, BFD_IND_SECTION_NAME, 3); 656#undef STD_SECTION 657 658struct section_hash_entry 659{ 660 struct bfd_hash_entry root; 661 asection section; 662}; 663 664/* Initialize an entry in the section hash table. */ 665 666struct bfd_hash_entry * 667bfd_section_hash_newfunc (entry, table, string) 668 struct bfd_hash_entry *entry; 669 struct bfd_hash_table *table; 670 const char *string; 671{ 672 /* Allocate the structure if it has not already been allocated by a 673 subclass. */ 674 if (entry == NULL) 675 { 676 entry = bfd_hash_allocate (table, sizeof (struct section_hash_entry)); 677 if (entry == NULL) 678 return entry; 679 } 680 681 /* Call the allocation method of the superclass. */ 682 entry = bfd_hash_newfunc (entry, table, string); 683 if (entry != NULL) 684 { 685 memset ((PTR) &((struct section_hash_entry *) entry)->section, 686 0, sizeof (asection)); 687 } 688 689 return entry; 690} 691 692#define section_hash_lookup(table, string, create, copy) \ 693 ((struct section_hash_entry *) \ 694 bfd_hash_lookup ((table), (string), (create), (copy))) 695 696/* Initializes a new section. NEWSECT->NAME is already set. */ 697 698static asection *bfd_section_init PARAMS ((bfd *, asection *)); 699 700static asection * 701bfd_section_init (abfd, newsect) 702 bfd *abfd; 703 asection *newsect; 704{ 705 static int section_id = 0x10; /* id 0 to 3 used by STD_SECTION. */ 706 707 newsect->id = section_id; 708 newsect->index = abfd->section_count; 709 newsect->owner = abfd; 710 711 /* Create a symbol whose only job is to point to this section. This 712 is useful for things like relocs which are relative to the base 713 of a section. */ 714 newsect->symbol = bfd_make_empty_symbol (abfd); 715 if (newsect->symbol == NULL) 716 return NULL; 717 718 newsect->symbol->name = newsect->name; 719 newsect->symbol->value = 0; 720 newsect->symbol->section = newsect; 721 newsect->symbol->flags = BSF_SECTION_SYM; 722 723 newsect->symbol_ptr_ptr = &newsect->symbol; 724 725 if (! BFD_SEND (abfd, _new_section_hook, (abfd, newsect))) 726 return NULL; 727 728 section_id++; 729 abfd->section_count++; 730 *abfd->section_tail = newsect; 731 abfd->section_tail = &newsect->next; 732 return newsect; 733} 734 735/* 736DOCDD 737INODE 738section prototypes, , typedef asection, Sections 739SUBSECTION 740 Section prototypes 741 742These are the functions exported by the section handling part of BFD. 743*/ 744 745/* 746FUNCTION 747 bfd_section_list_clear 748 749SYNOPSIS 750 void bfd_section_list_clear (bfd *); 751 752DESCRIPTION 753 Clears the section list, and also resets the section count and 754 hash table entries. 755*/ 756 757void 758bfd_section_list_clear (abfd) 759 bfd *abfd; 760{ 761 abfd->sections = NULL; 762 abfd->section_tail = &abfd->sections; 763 abfd->section_count = 0; 764 memset ((PTR) abfd->section_htab.table, 0, 765 abfd->section_htab.size * sizeof (struct bfd_hash_entry *)); 766} 767 768/* 769FUNCTION 770 bfd_get_section_by_name 771 772SYNOPSIS 773 asection *bfd_get_section_by_name(bfd *abfd, const char *name); 774 775DESCRIPTION 776 Run through @var{abfd} and return the one of the 777 <<asection>>s whose name matches @var{name}, otherwise <<NULL>>. 778 @xref{Sections}, for more information. 779 780 This should only be used in special cases; the normal way to process 781 all sections of a given name is to use <<bfd_map_over_sections>> and 782 <<strcmp>> on the name (or better yet, base it on the section flags 783 or something else) for each section. 784*/ 785 786asection * 787bfd_get_section_by_name (abfd, name) 788 bfd *abfd; 789 const char *name; 790{ 791 struct section_hash_entry *sh; 792 793 sh = section_hash_lookup (&abfd->section_htab, name, false, false); 794 if (sh != NULL) 795 return &sh->section; 796 797 return NULL; 798} 799 800/* 801FUNCTION 802 bfd_get_unique_section_name 803 804SYNOPSIS 805 char *bfd_get_unique_section_name(bfd *abfd, 806 const char *templat, 807 int *count); 808 809DESCRIPTION 810 Invent a section name that is unique in @var{abfd} by tacking 811 a dot and a digit suffix onto the original @var{templat}. If 812 @var{count} is non-NULL, then it specifies the first number 813 tried as a suffix to generate a unique name. The value 814 pointed to by @var{count} will be incremented in this case. 815*/ 816 817char * 818bfd_get_unique_section_name (abfd, templat, count) 819 bfd *abfd; 820 const char *templat; 821 int *count; 822{ 823 int num; 824 unsigned int len; 825 char *sname; 826 827 len = strlen (templat); 828 sname = bfd_malloc ((bfd_size_type) len + 8); 829 if (sname == NULL) 830 return NULL; 831 strcpy (sname, templat); 832 num = 1; 833 if (count != NULL) 834 num = *count; 835 836 do 837 { 838 /* If we have a million sections, something is badly wrong. */ 839 if (num > 999999) 840 abort (); 841 sprintf (sname + len, ".%d", num++); 842 } 843 while (section_hash_lookup (&abfd->section_htab, sname, false, false)); 844 845 if (count != NULL) 846 *count = num; 847 return sname; 848} 849 850/* 851FUNCTION 852 bfd_make_section_old_way 853 854SYNOPSIS 855 asection *bfd_make_section_old_way(bfd *abfd, const char *name); 856 857DESCRIPTION 858 Create a new empty section called @var{name} 859 and attach it to the end of the chain of sections for the 860 BFD @var{abfd}. An attempt to create a section with a name which 861 is already in use returns its pointer without changing the 862 section chain. 863 864 It has the funny name since this is the way it used to be 865 before it was rewritten.... 866 867 Possible errors are: 868 o <<bfd_error_invalid_operation>> - 869 If output has already started for this BFD. 870 o <<bfd_error_no_memory>> - 871 If memory allocation fails. 872 873*/ 874 875asection * 876bfd_make_section_old_way (abfd, name) 877 bfd *abfd; 878 const char *name; 879{ 880 struct section_hash_entry *sh; 881 asection *newsect; 882 883 if (abfd->output_has_begun) 884 { 885 bfd_set_error (bfd_error_invalid_operation); 886 return NULL; 887 } 888 889 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0) 890 return bfd_abs_section_ptr; 891 892 if (strcmp (name, BFD_COM_SECTION_NAME) == 0) 893 return bfd_com_section_ptr; 894 895 if (strcmp (name, BFD_UND_SECTION_NAME) == 0) 896 return bfd_und_section_ptr; 897 898 if (strcmp (name, BFD_IND_SECTION_NAME) == 0) 899 return bfd_ind_section_ptr; 900 901 sh = section_hash_lookup (&abfd->section_htab, name, true, false); 902 if (sh == NULL) 903 return NULL; 904 905 newsect = &sh->section; 906 if (newsect->name != NULL) 907 { 908 /* Section already exists. */ 909 return newsect; 910 } 911 912 newsect->name = name; 913 return bfd_section_init (abfd, newsect); 914} 915 916/* 917FUNCTION 918 bfd_make_section_anyway 919 920SYNOPSIS 921 asection *bfd_make_section_anyway(bfd *abfd, const char *name); 922 923DESCRIPTION 924 Create a new empty section called @var{name} and attach it to the end of 925 the chain of sections for @var{abfd}. Create a new section even if there 926 is already a section with that name. 927 928 Return <<NULL>> and set <<bfd_error>> on error; possible errors are: 929 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}. 930 o <<bfd_error_no_memory>> - If memory allocation fails. 931*/ 932 933sec_ptr 934bfd_make_section_anyway (abfd, name) 935 bfd *abfd; 936 const char *name; 937{ 938 struct section_hash_entry *sh; 939 asection *newsect; 940 941 if (abfd->output_has_begun) 942 { 943 bfd_set_error (bfd_error_invalid_operation); 944 return NULL; 945 } 946 947 sh = section_hash_lookup (&abfd->section_htab, name, true, false); 948 if (sh == NULL) 949 return NULL; 950 951 newsect = &sh->section; 952 if (newsect->name != NULL) 953 { 954 /* We are making a section of the same name. It can't go in 955 section_htab without generating a unique section name and 956 that would be pointless; We don't need to traverse the 957 hash table. */ 958 newsect = (asection *) bfd_zalloc (abfd, sizeof (asection)); 959 if (newsect == NULL) 960 return NULL; 961 } 962 963 newsect->name = name; 964 return bfd_section_init (abfd, newsect); 965} 966 967/* 968FUNCTION 969 bfd_make_section 970 971SYNOPSIS 972 asection *bfd_make_section(bfd *, const char *name); 973 974DESCRIPTION 975 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling 976 bfd_set_error ()) without changing the section chain if there is already a 977 section named @var{name}. If there is an error, return <<NULL>> and set 978 <<bfd_error>>. 979*/ 980 981asection * 982bfd_make_section (abfd, name) 983 bfd *abfd; 984 const char *name; 985{ 986 struct section_hash_entry *sh; 987 asection *newsect; 988 989 if (abfd->output_has_begun) 990 { 991 bfd_set_error (bfd_error_invalid_operation); 992 return NULL; 993 } 994 995 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0 996 || strcmp (name, BFD_COM_SECTION_NAME) == 0 997 || strcmp (name, BFD_UND_SECTION_NAME) == 0 998 || strcmp (name, BFD_IND_SECTION_NAME) == 0) 999 return NULL; 1000 1001 sh = section_hash_lookup (&abfd->section_htab, name, true, false); 1002 if (sh == NULL) 1003 return NULL; 1004 1005 newsect = &sh->section; 1006 if (newsect->name != NULL) 1007 { 1008 /* Section already exists. */ 1009 return newsect; 1010 } 1011 1012 newsect->name = name; 1013 return bfd_section_init (abfd, newsect); 1014} 1015 1016/* 1017FUNCTION 1018 bfd_set_section_flags 1019 1020SYNOPSIS 1021 boolean bfd_set_section_flags(bfd *abfd, asection *sec, flagword flags); 1022 1023DESCRIPTION 1024 Set the attributes of the section @var{sec} in the BFD 1025 @var{abfd} to the value @var{flags}. Return <<true>> on success, 1026 <<false>> on error. Possible error returns are: 1027 1028 o <<bfd_error_invalid_operation>> - 1029 The section cannot have one or more of the attributes 1030 requested. For example, a .bss section in <<a.out>> may not 1031 have the <<SEC_HAS_CONTENTS>> field set. 1032 1033*/ 1034 1035/*ARGSUSED*/ 1036boolean 1037bfd_set_section_flags (abfd, section, flags) 1038 bfd *abfd ATTRIBUTE_UNUSED; 1039 sec_ptr section; 1040 flagword flags; 1041{ 1042#if 0 1043 /* If you try to copy a text section from an input file (where it 1044 has the SEC_CODE flag set) to an output file, this loses big if 1045 the bfd_applicable_section_flags (abfd) doesn't have the SEC_CODE 1046 set - which it doesn't, at least not for a.out. FIXME */ 1047 1048 if ((flags & bfd_applicable_section_flags (abfd)) != flags) 1049 { 1050 bfd_set_error (bfd_error_invalid_operation); 1051 return false; 1052 } 1053#endif 1054 1055 section->flags = flags; 1056 return true; 1057} 1058 1059/* 1060FUNCTION 1061 bfd_map_over_sections 1062 1063SYNOPSIS 1064 void bfd_map_over_sections(bfd *abfd, 1065 void (*func) (bfd *abfd, 1066 asection *sect, 1067 PTR obj), 1068 PTR obj); 1069 1070DESCRIPTION 1071 Call the provided function @var{func} for each section 1072 attached to the BFD @var{abfd}, passing @var{obj} as an 1073 argument. The function will be called as if by 1074 1075| func(abfd, the_section, obj); 1076 1077 This is the prefered method for iterating over sections; an 1078 alternative would be to use a loop: 1079 1080| section *p; 1081| for (p = abfd->sections; p != NULL; p = p->next) 1082| func(abfd, p, ...) 1083 1084*/ 1085 1086/*VARARGS2*/ 1087void 1088bfd_map_over_sections (abfd, operation, user_storage) 1089 bfd *abfd; 1090 void (*operation) PARAMS ((bfd * abfd, asection * sect, PTR obj)); 1091 PTR user_storage; 1092{ 1093 asection *sect; 1094 unsigned int i = 0; 1095 1096 for (sect = abfd->sections; sect != NULL; i++, sect = sect->next) 1097 (*operation) (abfd, sect, user_storage); 1098 1099 if (i != abfd->section_count) /* Debugging */ 1100 abort (); 1101} 1102 1103/* 1104FUNCTION 1105 bfd_set_section_size 1106 1107SYNOPSIS 1108 boolean bfd_set_section_size(bfd *abfd, asection *sec, bfd_size_type val); 1109 1110DESCRIPTION 1111 Set @var{sec} to the size @var{val}. If the operation is 1112 ok, then <<true>> is returned, else <<false>>. 1113 1114 Possible error returns: 1115 o <<bfd_error_invalid_operation>> - 1116 Writing has started to the BFD, so setting the size is invalid. 1117 1118*/ 1119 1120boolean 1121bfd_set_section_size (abfd, ptr, val) 1122 bfd *abfd; 1123 sec_ptr ptr; 1124 bfd_size_type val; 1125{ 1126 /* Once you've started writing to any section you cannot create or change 1127 the size of any others. */ 1128 1129 if (abfd->output_has_begun) 1130 { 1131 bfd_set_error (bfd_error_invalid_operation); 1132 return false; 1133 } 1134 1135 ptr->_cooked_size = val; 1136 ptr->_raw_size = val; 1137 1138 return true; 1139} 1140 1141/* 1142FUNCTION 1143 bfd_set_section_contents 1144 1145SYNOPSIS 1146 boolean bfd_set_section_contents (bfd *abfd, asection *section, 1147 PTR data, file_ptr offset, 1148 bfd_size_type count); 1149 1150DESCRIPTION 1151 Sets the contents of the section @var{section} in BFD 1152 @var{abfd} to the data starting in memory at @var{data}. The 1153 data is written to the output section starting at offset 1154 @var{offset} for @var{count} octets. 1155 1156 Normally <<true>> is returned, else <<false>>. Possible error 1157 returns are: 1158 o <<bfd_error_no_contents>> - 1159 The output section does not have the <<SEC_HAS_CONTENTS>> 1160 attribute, so nothing can be written to it. 1161 o and some more too 1162 1163 This routine is front end to the back end function 1164 <<_bfd_set_section_contents>>. 1165 1166*/ 1167 1168#define bfd_get_section_size_now(abfd,sec) \ 1169(sec->reloc_done \ 1170 ? bfd_get_section_size_after_reloc (sec) \ 1171 : bfd_get_section_size_before_reloc (sec)) 1172 1173boolean 1174bfd_set_section_contents (abfd, section, location, offset, count) 1175 bfd *abfd; 1176 sec_ptr section; 1177 PTR location; 1178 file_ptr offset; 1179 bfd_size_type count; 1180{ 1181 bfd_size_type sz; 1182 1183 if (!(bfd_get_section_flags (abfd, section) & SEC_HAS_CONTENTS)) 1184 { 1185 bfd_set_error (bfd_error_no_contents); 1186 return (false); 1187 } 1188 1189 sz = bfd_get_section_size_now (abfd, section); 1190 if ((bfd_size_type) offset > sz 1191 || count > sz 1192 || offset + count > sz 1193 || count != (size_t) count) 1194 { 1195 bfd_set_error (bfd_error_bad_value); 1196 return false; 1197 } 1198 1199 switch (abfd->direction) 1200 { 1201 case read_direction: 1202 case no_direction: 1203 bfd_set_error (bfd_error_invalid_operation); 1204 return false; 1205 1206 case write_direction: 1207 break; 1208 1209 case both_direction: 1210 /* File is opened for update. `output_has_begun' some time ago when 1211 the file was created. Do not recompute sections sizes or alignments 1212 in _bfd_set_section_content. */ 1213 abfd->output_has_begun = true; 1214 break; 1215 } 1216 1217 /* Record a copy of the data in memory if desired. */ 1218 if (section->contents 1219 && location != section->contents + offset) 1220 memcpy (section->contents + offset, location, (size_t) count); 1221 1222 if (BFD_SEND (abfd, _bfd_set_section_contents, 1223 (abfd, section, location, offset, count))) 1224 { 1225 abfd->output_has_begun = true; 1226 return true; 1227 } 1228 1229 return false; 1230} 1231 1232/* 1233FUNCTION 1234 bfd_get_section_contents 1235 1236SYNOPSIS 1237 boolean bfd_get_section_contents (bfd *abfd, asection *section, 1238 PTR location, file_ptr offset, 1239 bfd_size_type count); 1240 1241DESCRIPTION 1242 Read data from @var{section} in BFD @var{abfd} 1243 into memory starting at @var{location}. The data is read at an 1244 offset of @var{offset} from the start of the input section, 1245 and is read for @var{count} bytes. 1246 1247 If the contents of a constructor with the <<SEC_CONSTRUCTOR>> 1248 flag set are requested or if the section does not have the 1249 <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled 1250 with zeroes. If no errors occur, <<true>> is returned, else 1251 <<false>>. 1252 1253*/ 1254boolean 1255bfd_get_section_contents (abfd, section, location, offset, count) 1256 bfd *abfd; 1257 sec_ptr section; 1258 PTR location; 1259 file_ptr offset; 1260 bfd_size_type count; 1261{ 1262 bfd_size_type sz; 1263 1264 if (section->flags & SEC_CONSTRUCTOR) 1265 { 1266 memset (location, 0, (size_t) count); 1267 return true; 1268 } 1269 1270 /* Even if reloc_done is true, this function reads unrelocated 1271 contents, so we want the raw size. */ 1272 sz = section->_raw_size; 1273 if ((bfd_size_type) offset > sz 1274 || count > sz 1275 || offset + count > sz 1276 || count != (size_t) count) 1277 { 1278 bfd_set_error (bfd_error_bad_value); 1279 return false; 1280 } 1281 1282 if (count == 0) 1283 /* Don't bother. */ 1284 return true; 1285 1286 if ((section->flags & SEC_HAS_CONTENTS) == 0) 1287 { 1288 memset (location, 0, (size_t) count); 1289 return true; 1290 } 1291 1292 if ((section->flags & SEC_IN_MEMORY) != 0) 1293 { 1294 memcpy (location, section->contents + offset, (size_t) count); 1295 return true; 1296 } 1297 1298 return BFD_SEND (abfd, _bfd_get_section_contents, 1299 (abfd, section, location, offset, count)); 1300} 1301 1302/* 1303FUNCTION 1304 bfd_copy_private_section_data 1305 1306SYNOPSIS 1307 boolean bfd_copy_private_section_data (bfd *ibfd, asection *isec, 1308 bfd *obfd, asection *osec); 1309 1310DESCRIPTION 1311 Copy private section information from @var{isec} in the BFD 1312 @var{ibfd} to the section @var{osec} in the BFD @var{obfd}. 1313 Return <<true>> on success, <<false>> on error. Possible error 1314 returns are: 1315 1316 o <<bfd_error_no_memory>> - 1317 Not enough memory exists to create private data for @var{osec}. 1318 1319.#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \ 1320. BFD_SEND (obfd, _bfd_copy_private_section_data, \ 1321. (ibfd, isection, obfd, osection)) 1322*/ 1323 1324/* 1325FUNCTION 1326 _bfd_strip_section_from_output 1327 1328SYNOPSIS 1329 void _bfd_strip_section_from_output 1330 (struct bfd_link_info *info, asection *section); 1331 1332DESCRIPTION 1333 Remove @var{section} from the output. If the output section 1334 becomes empty, remove it from the output bfd. @var{info} may 1335 be NULL; if it is not, it is used to decide whether the output 1336 section is empty. 1337*/ 1338void 1339_bfd_strip_section_from_output (info, s) 1340 struct bfd_link_info *info; 1341 asection *s; 1342{ 1343 asection **spp, *os; 1344 struct bfd_link_order *p, *pp; 1345 boolean keep_os; 1346 1347 /* Excise the input section from the link order. 1348 1349 FIXME: For all calls that I can see to this function, the link 1350 orders have not yet been set up. So why are we checking them? -- 1351 Ian */ 1352 os = s->output_section; 1353 1354 /* Handle a section that wasn't output. */ 1355 if (os == NULL) 1356 return; 1357 1358 for (p = os->link_order_head, pp = NULL; p != NULL; pp = p, p = p->next) 1359 if (p->type == bfd_indirect_link_order 1360 && p->u.indirect.section == s) 1361 { 1362 if (pp) 1363 pp->next = p->next; 1364 else 1365 os->link_order_head = p->next; 1366 if (!p->next) 1367 os->link_order_tail = pp; 1368 break; 1369 } 1370 1371 keep_os = os->link_order_head != NULL; 1372 1373 if (! keep_os && info != NULL) 1374 { 1375 bfd *abfd; 1376 for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link_next) 1377 { 1378 asection *is; 1379 for (is = abfd->sections; is != NULL; is = is->next) 1380 { 1381 if (is != s && is->output_section == os 1382 && (is->flags & SEC_EXCLUDE) == 0) 1383 break; 1384 } 1385 if (is != NULL) 1386 break; 1387 } 1388 if (abfd != NULL) 1389 keep_os = true; 1390 } 1391 1392 /* If the output section is empty, remove it too. Careful about sections 1393 that have been discarded in the link script -- they are mapped to 1394 bfd_abs_section, which has no owner. */ 1395 if (!keep_os && os->owner != NULL) 1396 { 1397 for (spp = &os->owner->sections; *spp; spp = &(*spp)->next) 1398 if (*spp == os) 1399 { 1400 bfd_section_list_remove (os->owner, spp); 1401 os->owner->section_count--; 1402 break; 1403 } 1404 } 1405 1406 s->flags |= SEC_EXCLUDE; 1407} 1408