section.c revision 91041
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. const char *name; 174. 175. {* A unique sequence number. *} 176. int id; 177. 178. {* Which section in the bfd; 0..n-1 as sections are created in a bfd. *} 179. int index; 180. 181. {* The next section in the list belonging to the BFD, or NULL. *} 182. struct sec *next; 183. 184. {* The field flags contains attributes of the section. Some 185. flags are read in from the object file, and some are 186. synthesized from other information. *} 187. flagword flags; 188. 189.#define SEC_NO_FLAGS 0x000 190. 191. {* Tells the OS to allocate space for this section when loading. 192. This is clear for a section containing debug information only. *} 193.#define SEC_ALLOC 0x001 194. 195. {* Tells the OS to load the section from the file when loading. 196. This is clear for a .bss section. *} 197.#define SEC_LOAD 0x002 198. 199. {* The section contains data still to be relocated, so there is 200. some relocation information too. *} 201.#define SEC_RELOC 0x004 202. 203. {* ELF reserves 4 processor specific bits and 8 operating system 204. specific bits in sh_flags; at present we can get away with just 205. one in communicating between the assembler and BFD, but this 206. isn't a good long-term solution. *} 207.#define SEC_ARCH_BIT_0 0x008 208. 209. {* A signal to the OS that the section contains read only data. *} 210.#define SEC_READONLY 0x010 211. 212. {* The section contains code only. *} 213.#define SEC_CODE 0x020 214. 215. {* The section contains data only. *} 216.#define SEC_DATA 0x040 217. 218. {* The section will reside in ROM. *} 219.#define SEC_ROM 0x080 220. 221. {* The section contains constructor information. This section 222. type is used by the linker to create lists of constructors and 223. destructors used by <<g++>>. When a back end sees a symbol 224. which should be used in a constructor list, it creates a new 225. section for the type of name (e.g., <<__CTOR_LIST__>>), attaches 226. the symbol to it, and builds a relocation. To build the lists 227. of constructors, all the linker has to do is catenate all the 228. sections called <<__CTOR_LIST__>> and relocate the data 229. contained within - exactly the operations it would peform on 230. standard data. *} 231.#define SEC_CONSTRUCTOR 0x100 232. 233. {* The section is a constructor, and should be placed at the 234. end of the text, data, or bss section(?). *} 235.#define SEC_CONSTRUCTOR_TEXT 0x1100 236.#define SEC_CONSTRUCTOR_DATA 0x2100 237.#define SEC_CONSTRUCTOR_BSS 0x3100 238. 239. {* The section has contents - a data section could be 240. <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>; a debug section could be 241. <<SEC_HAS_CONTENTS>> *} 242.#define SEC_HAS_CONTENTS 0x200 243. 244. {* An instruction to the linker to not output the section 245. even if it has information which would normally be written. *} 246.#define SEC_NEVER_LOAD 0x400 247. 248. {* The section is a COFF shared library section. This flag is 249. only for the linker. If this type of section appears in 250. the input file, the linker must copy it to the output file 251. without changing the vma or size. FIXME: Although this 252. was originally intended to be general, it really is COFF 253. specific (and the flag was renamed to indicate this). It 254. might be cleaner to have some more general mechanism to 255. allow the back end to control what the linker does with 256. sections. *} 257.#define SEC_COFF_SHARED_LIBRARY 0x800 258. 259. {* The section has GOT references. This flag is only for the 260. linker, and is currently only used by the elf32-hppa back end. 261. It will be set if global offset table references were detected 262. in this section, which indicate to the linker that the section 263. contains PIC code, and must be handled specially when doing a 264. static link. *} 265.#define SEC_HAS_GOT_REF 0x4000 266. 267. {* The section contains common symbols (symbols may be defined 268. multiple times, the value of a symbol is the amount of 269. space it requires, and the largest symbol value is the one 270. used). Most targets have exactly one of these (which we 271. translate to bfd_com_section_ptr), but ECOFF has two. *} 272.#define SEC_IS_COMMON 0x8000 273. 274. {* The section contains only debugging information. For 275. example, this is set for ELF .debug and .stab sections. 276. strip tests this flag to see if a section can be 277. discarded. *} 278.#define SEC_DEBUGGING 0x10000 279. 280. {* The contents of this section are held in memory pointed to 281. by the contents field. This is checked by bfd_get_section_contents, 282. and the data is retrieved from memory if appropriate. *} 283.#define SEC_IN_MEMORY 0x20000 284. 285. {* The contents of this section are to be excluded by the 286. linker for executable and shared objects unless those 287. objects are to be further relocated. *} 288.#define SEC_EXCLUDE 0x40000 289. 290. {* The contents of this section are to be sorted based on the sum of 291. the symbol and addend values specified by the associated relocation 292. entries. Entries without associated relocation entries will be 293. appended to the end of the section in an unspecified order. *} 294.#define SEC_SORT_ENTRIES 0x80000 295. 296. {* When linking, duplicate sections of the same name should be 297. discarded, rather than being combined into a single section as 298. is usually done. This is similar to how common symbols are 299. handled. See SEC_LINK_DUPLICATES below. *} 300.#define SEC_LINK_ONCE 0x100000 301. 302. {* If SEC_LINK_ONCE is set, this bitfield describes how the linker 303. should handle duplicate sections. *} 304.#define SEC_LINK_DUPLICATES 0x600000 305. 306. {* This value for SEC_LINK_DUPLICATES means that duplicate 307. sections with the same name should simply be discarded. *} 308.#define SEC_LINK_DUPLICATES_DISCARD 0x0 309. 310. {* This value for SEC_LINK_DUPLICATES means that the linker 311. should warn if there are any duplicate sections, although 312. it should still only link one copy. *} 313.#define SEC_LINK_DUPLICATES_ONE_ONLY 0x200000 314. 315. {* This value for SEC_LINK_DUPLICATES means that the linker 316. should warn if any duplicate sections are a different size. *} 317.#define SEC_LINK_DUPLICATES_SAME_SIZE 0x400000 318. 319. {* This value for SEC_LINK_DUPLICATES means that the linker 320. should warn if any duplicate sections contain different 321. contents. *} 322.#define SEC_LINK_DUPLICATES_SAME_CONTENTS 0x600000 323. 324. {* This section was created by the linker as part of dynamic 325. relocation or other arcane processing. It is skipped when 326. going through the first-pass output, trusting that someone 327. else up the line will take care of it later. *} 328.#define SEC_LINKER_CREATED 0x800000 329. 330. {* This section should not be subject to garbage collection. *} 331.#define SEC_KEEP 0x1000000 332. 333. {* This section contains "short" data, and should be placed 334. "near" the GP. *} 335.#define SEC_SMALL_DATA 0x2000000 336. 337. {* This section contains data which may be shared with other 338. executables or shared objects. *} 339.#define SEC_SHARED 0x4000000 340. 341. {* When a section with this flag is being linked, then if the size of 342. the input section is less than a page, it should not cross a page 343. boundary. If the size of the input section is one page or more, it 344. should be aligned on a page boundary. *} 345.#define SEC_BLOCK 0x8000000 346. 347. {* Conditionally link this section; do not link if there are no 348. references found to any symbol in the section. *} 349.#define SEC_CLINK 0x10000000 350. 351. {* Attempt to merge identical entities in the section. 352. Entity size is given in the entsize field. *} 353.#define SEC_MERGE 0x20000000 354. 355. {* If given with SEC_MERGE, entities to merge are zero terminated 356. strings where entsize specifies character size instead of fixed 357. size entries. *} 358.#define SEC_STRINGS 0x40000000 359. 360. {* This section contains data about section groups. *} 361.#define SEC_GROUP 0x80000000 362. 363. {* End of section flags. *} 364. 365. {* Some internal packed boolean fields. *} 366. 367. {* See the vma field. *} 368. unsigned int user_set_vma : 1; 369. 370. {* Whether relocations have been processed. *} 371. unsigned int reloc_done : 1; 372. 373. {* A mark flag used by some of the linker backends. *} 374. unsigned int linker_mark : 1; 375. 376. {* Another mark flag used by some of the linker backends. Set for 377. output sections that have an input section. *} 378. unsigned int linker_has_input : 1; 379. 380. {* A mark flag used by some linker backends for garbage collection. *} 381. unsigned int gc_mark : 1; 382. 383. {* Used by the ELF code to mark sections which have been allocated 384. to segments. *} 385. unsigned int segment_mark : 1; 386. 387. {* End of internal packed boolean fields. *} 388. 389. {* The virtual memory address of the section - where it will be 390. at run time. The symbols are relocated against this. The 391. user_set_vma flag is maintained by bfd; if it's not set, the 392. backend can assign addresses (for example, in <<a.out>>, where 393. the default address for <<.data>> is dependent on the specific 394. target and various flags). *} 395. bfd_vma vma; 396. 397. {* The load address of the section - where it would be in a 398. rom image; really only used for writing section header 399. information. *} 400. bfd_vma lma; 401. 402. {* The size of the section in octets, as it will be output. 403. Contains a value even if the section has no contents (e.g., the 404. size of <<.bss>>). This will be filled in after relocation. *} 405. bfd_size_type _cooked_size; 406. 407. {* The original size on disk of the section, in octets. Normally this 408. value is the same as the size, but if some relaxing has 409. been done, then this value will be bigger. *} 410. bfd_size_type _raw_size; 411. 412. {* If this section is going to be output, then this value is the 413. offset in *bytes* into the output section of the first byte in the 414. input section (byte ==> smallest addressable unit on the 415. target). In most cases, if this was going to start at the 416. 100th octet (8-bit quantity) in the output section, this value 417. would be 100. However, if the target byte size is 16 bits 418. (bfd_octets_per_byte is "2"), this value would be 50. *} 419. bfd_vma output_offset; 420. 421. {* The output section through which to map on output. *} 422. struct sec *output_section; 423. 424. {* The alignment requirement of the section, as an exponent of 2 - 425. e.g., 3 aligns to 2^3 (or 8). *} 426. unsigned int alignment_power; 427. 428. {* If an input section, a pointer to a vector of relocation 429. records for the data in this section. *} 430. struct reloc_cache_entry *relocation; 431. 432. {* If an output section, a pointer to a vector of pointers to 433. relocation records for the data in this section. *} 434. struct reloc_cache_entry **orelocation; 435. 436. {* The number of relocation records in one of the above. *} 437. unsigned reloc_count; 438. 439. {* Information below is back end specific - and not always used 440. or updated. *} 441. 442. {* File position of section data. *} 443. file_ptr filepos; 444. 445. {* File position of relocation info. *} 446. file_ptr rel_filepos; 447. 448. {* File position of line data. *} 449. file_ptr line_filepos; 450. 451. {* Pointer to data for applications. *} 452. PTR userdata; 453. 454. {* If the SEC_IN_MEMORY flag is set, this points to the actual 455. contents. *} 456. unsigned char *contents; 457. 458. {* Attached line number information. *} 459. alent *lineno; 460. 461. {* Number of line number records. *} 462. unsigned int lineno_count; 463. 464. {* Entity size for merging purposes. *} 465. unsigned int entsize; 466. 467. {* Optional information about a COMDAT entry; NULL if not COMDAT. *} 468. struct bfd_comdat_info *comdat; 469. 470. {* When a section is being output, this value changes as more 471. linenumbers are written out. *} 472. file_ptr moving_line_filepos; 473. 474. {* What the section number is in the target world. *} 475. int target_index; 476. 477. PTR used_by_bfd; 478. 479. {* If this is a constructor section then here is a list of the 480. relocations created to relocate items within it. *} 481. struct relent_chain *constructor_chain; 482. 483. {* The BFD which owns the section. *} 484. bfd *owner; 485. 486. {* A symbol which points at this section only. *} 487. struct symbol_cache_entry *symbol; 488. struct symbol_cache_entry **symbol_ptr_ptr; 489. 490. struct bfd_link_order *link_order_head; 491. struct bfd_link_order *link_order_tail; 492.} asection; 493. 494.{* These sections are global, and are managed by BFD. The application 495. and target back end are not permitted to change the values in 496. these sections. New code should use the section_ptr macros rather 497. than referring directly to the const sections. The const sections 498. may eventually vanish. *} 499.#define BFD_ABS_SECTION_NAME "*ABS*" 500.#define BFD_UND_SECTION_NAME "*UND*" 501.#define BFD_COM_SECTION_NAME "*COM*" 502.#define BFD_IND_SECTION_NAME "*IND*" 503. 504.{* The absolute section. *} 505.extern const asection bfd_abs_section; 506.#define bfd_abs_section_ptr ((asection *) &bfd_abs_section) 507.#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr) 508.{* Pointer to the undefined section. *} 509.extern const asection bfd_und_section; 510.#define bfd_und_section_ptr ((asection *) &bfd_und_section) 511.#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr) 512.{* Pointer to the common section. *} 513.extern const asection bfd_com_section; 514.#define bfd_com_section_ptr ((asection *) &bfd_com_section) 515.{* Pointer to the indirect section. *} 516.extern const asection bfd_ind_section; 517.#define bfd_ind_section_ptr ((asection *) &bfd_ind_section) 518.#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr) 519. 520.#define bfd_is_const_section(SEC) \ 521. ( ((SEC) == bfd_abs_section_ptr) \ 522. || ((SEC) == bfd_und_section_ptr) \ 523. || ((SEC) == bfd_com_section_ptr) \ 524. || ((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.{* Macros to handle insertion and deletion of a bfd's sections. These 538. only handle the list pointers, ie. do not adjust section_count, 539. target_index etc. *} 540.#define bfd_section_list_remove(ABFD, PS) \ 541. do \ 542. { \ 543. asection **_ps = PS; \ 544. asection *_s = *_ps; \ 545. *_ps = _s->next; \ 546. if (_s->next == NULL) \ 547. (ABFD)->section_tail = _ps; \ 548. } \ 549. while (0) 550.#define bfd_section_list_insert(ABFD, PS, S) \ 551. do \ 552. { \ 553. asection **_ps = PS; \ 554. asection *_s = S; \ 555. _s->next = *_ps; \ 556. *_ps = _s; \ 557. if (_s->next == NULL) \ 558. (ABFD)->section_tail = &_s->next; \ 559. } \ 560. while (0) 561. 562*/ 563 564/* We use a macro to initialize the static asymbol structures because 565 traditional C does not permit us to initialize a union member while 566 gcc warns if we don't initialize it. */ 567 /* the_bfd, name, value, attr, section [, udata] */ 568#ifdef __STDC__ 569#define GLOBAL_SYM_INIT(NAME, SECTION) \ 570 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION, { 0 }} 571#else 572#define GLOBAL_SYM_INIT(NAME, SECTION) \ 573 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION } 574#endif 575 576/* These symbols are global, not specific to any BFD. Therefore, anything 577 that tries to change them is broken, and should be repaired. */ 578 579static const asymbol global_syms[] = 580{ 581 GLOBAL_SYM_INIT (BFD_COM_SECTION_NAME, &bfd_com_section), 582 GLOBAL_SYM_INIT (BFD_UND_SECTION_NAME, &bfd_und_section), 583 GLOBAL_SYM_INIT (BFD_ABS_SECTION_NAME, &bfd_abs_section), 584 GLOBAL_SYM_INIT (BFD_IND_SECTION_NAME, &bfd_ind_section) 585}; 586 587#define STD_SECTION(SEC, FLAGS, SYM, NAME, IDX) \ 588 const asymbol * const SYM = (asymbol *) &global_syms[IDX]; \ 589 const asection SEC = \ 590 /* name, id, index, next, flags, user_set_vma, reloc_done, */ \ 591 { NAME, IDX, 0, NULL, FLAGS, 0, 0, \ 592 \ 593 /* linker_mark, linker_has_input, gc_mark, segment_mark, */ \ 594 0, 0, 1, 0, \ 595 \ 596 /* vma, lma, _cooked_size, _raw_size, */ \ 597 0, 0, 0, 0, \ 598 \ 599 /* output_offset, output_section, alignment_power, */ \ 600 0, (struct sec *) &SEC, 0, \ 601 \ 602 /* relocation, orelocation, reloc_count, filepos, rel_filepos, */ \ 603 NULL, NULL, 0, 0, 0, \ 604 \ 605 /* line_filepos, userdata, contents, lineno, lineno_count, */ \ 606 0, NULL, NULL, NULL, 0, \ 607 \ 608 /* entsize, comdat, moving_line_filepos, */ \ 609 0, NULL, 0, \ 610 \ 611 /* target_index, used_by_bfd, constructor_chain, owner, */ \ 612 0, NULL, NULL, NULL, \ 613 \ 614 /* symbol, */ \ 615 (struct symbol_cache_entry *) &global_syms[IDX], \ 616 \ 617 /* symbol_ptr_ptr, */ \ 618 (struct symbol_cache_entry **) &SYM, \ 619 \ 620 /* link_order_head, link_order_tail */ \ 621 NULL, NULL \ 622 } 623 624STD_SECTION (bfd_com_section, SEC_IS_COMMON, bfd_com_symbol, 625 BFD_COM_SECTION_NAME, 0); 626STD_SECTION (bfd_und_section, 0, bfd_und_symbol, BFD_UND_SECTION_NAME, 1); 627STD_SECTION (bfd_abs_section, 0, bfd_abs_symbol, BFD_ABS_SECTION_NAME, 2); 628STD_SECTION (bfd_ind_section, 0, bfd_ind_symbol, BFD_IND_SECTION_NAME, 3); 629#undef STD_SECTION 630 631struct section_hash_entry 632{ 633 struct bfd_hash_entry root; 634 asection section; 635}; 636 637/* Initialize an entry in the section hash table. */ 638 639struct bfd_hash_entry * 640bfd_section_hash_newfunc (entry, table, string) 641 struct bfd_hash_entry *entry; 642 struct bfd_hash_table *table; 643 const char *string; 644{ 645 /* Allocate the structure if it has not already been allocated by a 646 subclass. */ 647 if (entry == NULL) 648 { 649 entry = bfd_hash_allocate (table, sizeof (struct section_hash_entry)); 650 if (entry == NULL) 651 return entry; 652 } 653 654 /* Call the allocation method of the superclass. */ 655 entry = bfd_hash_newfunc (entry, table, string); 656 if (entry != NULL) 657 { 658 memset ((PTR) &((struct section_hash_entry *) entry)->section, 659 0, sizeof (asection)); 660 } 661 662 return entry; 663} 664 665#define section_hash_lookup(table, string, create, copy) \ 666 ((struct section_hash_entry *) \ 667 bfd_hash_lookup ((table), (string), (create), (copy))) 668 669/* Initializes a new section. NEWSECT->NAME is already set. */ 670 671static asection *bfd_section_init PARAMS ((bfd *, asection *)); 672 673static asection * 674bfd_section_init (abfd, newsect) 675 bfd *abfd; 676 asection *newsect; 677{ 678 static int section_id = 0x10; /* id 0 to 3 used by STD_SECTION. */ 679 680 newsect->id = section_id; 681 newsect->index = abfd->section_count; 682 newsect->owner = abfd; 683 684 /* Create a symbol whose only job is to point to this section. This 685 is useful for things like relocs which are relative to the base 686 of a section. */ 687 newsect->symbol = bfd_make_empty_symbol (abfd); 688 if (newsect->symbol == NULL) 689 return NULL; 690 691 newsect->symbol->name = newsect->name; 692 newsect->symbol->value = 0; 693 newsect->symbol->section = newsect; 694 newsect->symbol->flags = BSF_SECTION_SYM; 695 696 newsect->symbol_ptr_ptr = &newsect->symbol; 697 698 if (! BFD_SEND (abfd, _new_section_hook, (abfd, newsect))) 699 return NULL; 700 701 section_id++; 702 abfd->section_count++; 703 *abfd->section_tail = newsect; 704 abfd->section_tail = &newsect->next; 705 return newsect; 706} 707 708/* 709DOCDD 710INODE 711section prototypes, , typedef asection, Sections 712SUBSECTION 713 Section prototypes 714 715These are the functions exported by the section handling part of BFD. 716*/ 717 718/* 719FUNCTION 720 bfd_section_list_clear 721 722SYNOPSIS 723 void bfd_section_list_clear (bfd *); 724 725DESCRIPTION 726 Clears the section list, and also resets the section count and 727 hash table entries. 728*/ 729 730void 731bfd_section_list_clear (abfd) 732 bfd *abfd; 733{ 734 abfd->sections = NULL; 735 abfd->section_tail = &abfd->sections; 736 abfd->section_count = 0; 737 memset ((PTR) abfd->section_htab.table, 0, 738 abfd->section_htab.size * sizeof (struct bfd_hash_entry *)); 739} 740 741/* 742FUNCTION 743 bfd_get_section_by_name 744 745SYNOPSIS 746 asection *bfd_get_section_by_name(bfd *abfd, const char *name); 747 748DESCRIPTION 749 Run through @var{abfd} and return the one of the 750 <<asection>>s whose name matches @var{name}, otherwise <<NULL>>. 751 @xref{Sections}, for more information. 752 753 This should only be used in special cases; the normal way to process 754 all sections of a given name is to use <<bfd_map_over_sections>> and 755 <<strcmp>> on the name (or better yet, base it on the section flags 756 or something else) for each section. 757*/ 758 759asection * 760bfd_get_section_by_name (abfd, name) 761 bfd *abfd; 762 const char *name; 763{ 764 struct section_hash_entry *sh; 765 766 sh = section_hash_lookup (&abfd->section_htab, name, false, false); 767 if (sh != NULL) 768 return &sh->section; 769 770 return NULL; 771} 772 773/* 774FUNCTION 775 bfd_get_unique_section_name 776 777SYNOPSIS 778 char *bfd_get_unique_section_name(bfd *abfd, 779 const char *templat, 780 int *count); 781 782DESCRIPTION 783 Invent a section name that is unique in @var{abfd} by tacking 784 a dot and a digit suffix onto the original @var{templat}. If 785 @var{count} is non-NULL, then it specifies the first number 786 tried as a suffix to generate a unique name. The value 787 pointed to by @var{count} will be incremented in this case. 788*/ 789 790char * 791bfd_get_unique_section_name (abfd, templat, count) 792 bfd *abfd; 793 const char *templat; 794 int *count; 795{ 796 int num; 797 unsigned int len; 798 char *sname; 799 800 len = strlen (templat); 801 sname = bfd_malloc ((bfd_size_type) len + 8); 802 if (sname == NULL) 803 return NULL; 804 strcpy (sname, templat); 805 num = 1; 806 if (count != NULL) 807 num = *count; 808 809 do 810 { 811 /* If we have a million sections, something is badly wrong. */ 812 if (num > 999999) 813 abort (); 814 sprintf (sname + len, ".%d", num++); 815 } 816 while (section_hash_lookup (&abfd->section_htab, sname, false, false)); 817 818 if (count != NULL) 819 *count = num; 820 return sname; 821} 822 823/* 824FUNCTION 825 bfd_make_section_old_way 826 827SYNOPSIS 828 asection *bfd_make_section_old_way(bfd *abfd, const char *name); 829 830DESCRIPTION 831 Create a new empty section called @var{name} 832 and attach it to the end of the chain of sections for the 833 BFD @var{abfd}. An attempt to create a section with a name which 834 is already in use returns its pointer without changing the 835 section chain. 836 837 It has the funny name since this is the way it used to be 838 before it was rewritten.... 839 840 Possible errors are: 841 o <<bfd_error_invalid_operation>> - 842 If output has already started for this BFD. 843 o <<bfd_error_no_memory>> - 844 If memory allocation fails. 845 846*/ 847 848asection * 849bfd_make_section_old_way (abfd, name) 850 bfd *abfd; 851 const char *name; 852{ 853 struct section_hash_entry *sh; 854 asection *newsect; 855 856 if (abfd->output_has_begun) 857 { 858 bfd_set_error (bfd_error_invalid_operation); 859 return NULL; 860 } 861 862 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0) 863 return bfd_abs_section_ptr; 864 865 if (strcmp (name, BFD_COM_SECTION_NAME) == 0) 866 return bfd_com_section_ptr; 867 868 if (strcmp (name, BFD_UND_SECTION_NAME) == 0) 869 return bfd_und_section_ptr; 870 871 if (strcmp (name, BFD_IND_SECTION_NAME) == 0) 872 return bfd_ind_section_ptr; 873 874 sh = section_hash_lookup (&abfd->section_htab, name, true, false); 875 if (sh == NULL) 876 return NULL; 877 878 newsect = &sh->section; 879 if (newsect->name != NULL) 880 { 881 /* Section already exists. */ 882 return newsect; 883 } 884 885 newsect->name = name; 886 return bfd_section_init (abfd, newsect); 887} 888 889/* 890FUNCTION 891 bfd_make_section_anyway 892 893SYNOPSIS 894 asection *bfd_make_section_anyway(bfd *abfd, const char *name); 895 896DESCRIPTION 897 Create a new empty section called @var{name} and attach it to the end of 898 the chain of sections for @var{abfd}. Create a new section even if there 899 is already a section with that name. 900 901 Return <<NULL>> and set <<bfd_error>> on error; possible errors are: 902 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}. 903 o <<bfd_error_no_memory>> - If memory allocation fails. 904*/ 905 906sec_ptr 907bfd_make_section_anyway (abfd, name) 908 bfd *abfd; 909 const char *name; 910{ 911 struct section_hash_entry *sh; 912 asection *newsect; 913 914 if (abfd->output_has_begun) 915 { 916 bfd_set_error (bfd_error_invalid_operation); 917 return NULL; 918 } 919 920 sh = section_hash_lookup (&abfd->section_htab, name, true, false); 921 if (sh == NULL) 922 return NULL; 923 924 newsect = &sh->section; 925 if (newsect->name != NULL) 926 { 927 /* We are making a section of the same name. It can't go in 928 section_htab without generating a unique section name and 929 that would be pointless; We don't need to traverse the 930 hash table. */ 931 newsect = (asection *) bfd_zalloc (abfd, sizeof (asection)); 932 if (newsect == NULL) 933 return NULL; 934 } 935 936 newsect->name = name; 937 return bfd_section_init (abfd, newsect); 938} 939 940/* 941FUNCTION 942 bfd_make_section 943 944SYNOPSIS 945 asection *bfd_make_section(bfd *, const char *name); 946 947DESCRIPTION 948 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling 949 bfd_set_error ()) without changing the section chain if there is already a 950 section named @var{name}. If there is an error, return <<NULL>> and set 951 <<bfd_error>>. 952*/ 953 954asection * 955bfd_make_section (abfd, name) 956 bfd *abfd; 957 const char *name; 958{ 959 struct section_hash_entry *sh; 960 asection *newsect; 961 962 if (abfd->output_has_begun) 963 { 964 bfd_set_error (bfd_error_invalid_operation); 965 return NULL; 966 } 967 968 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0 969 || strcmp (name, BFD_COM_SECTION_NAME) == 0 970 || strcmp (name, BFD_UND_SECTION_NAME) == 0 971 || strcmp (name, BFD_IND_SECTION_NAME) == 0) 972 return NULL; 973 974 sh = section_hash_lookup (&abfd->section_htab, name, true, false); 975 if (sh == NULL) 976 return NULL; 977 978 newsect = &sh->section; 979 if (newsect->name != NULL) 980 { 981 /* Section already exists. */ 982 return newsect; 983 } 984 985 newsect->name = name; 986 return bfd_section_init (abfd, newsect); 987} 988 989/* 990FUNCTION 991 bfd_set_section_flags 992 993SYNOPSIS 994 boolean bfd_set_section_flags(bfd *abfd, asection *sec, flagword flags); 995 996DESCRIPTION 997 Set the attributes of the section @var{sec} in the BFD 998 @var{abfd} to the value @var{flags}. Return <<true>> on success, 999 <<false>> on error. Possible error returns are: 1000 1001 o <<bfd_error_invalid_operation>> - 1002 The section cannot have one or more of the attributes 1003 requested. For example, a .bss section in <<a.out>> may not 1004 have the <<SEC_HAS_CONTENTS>> field set. 1005 1006*/ 1007 1008/*ARGSUSED*/ 1009boolean 1010bfd_set_section_flags (abfd, section, flags) 1011 bfd *abfd ATTRIBUTE_UNUSED; 1012 sec_ptr section; 1013 flagword flags; 1014{ 1015#if 0 1016 /* If you try to copy a text section from an input file (where it 1017 has the SEC_CODE flag set) to an output file, this loses big if 1018 the bfd_applicable_section_flags (abfd) doesn't have the SEC_CODE 1019 set - which it doesn't, at least not for a.out. FIXME */ 1020 1021 if ((flags & bfd_applicable_section_flags (abfd)) != flags) 1022 { 1023 bfd_set_error (bfd_error_invalid_operation); 1024 return false; 1025 } 1026#endif 1027 1028 section->flags = flags; 1029 return true; 1030} 1031 1032/* 1033FUNCTION 1034 bfd_map_over_sections 1035 1036SYNOPSIS 1037 void bfd_map_over_sections(bfd *abfd, 1038 void (*func) (bfd *abfd, 1039 asection *sect, 1040 PTR obj), 1041 PTR obj); 1042 1043DESCRIPTION 1044 Call the provided function @var{func} for each section 1045 attached to the BFD @var{abfd}, passing @var{obj} as an 1046 argument. The function will be called as if by 1047 1048| func(abfd, the_section, obj); 1049 1050 This is the prefered method for iterating over sections; an 1051 alternative would be to use a loop: 1052 1053| section *p; 1054| for (p = abfd->sections; p != NULL; p = p->next) 1055| func(abfd, p, ...) 1056 1057*/ 1058 1059/*VARARGS2*/ 1060void 1061bfd_map_over_sections (abfd, operation, user_storage) 1062 bfd *abfd; 1063 void (*operation) PARAMS ((bfd * abfd, asection * sect, PTR obj)); 1064 PTR user_storage; 1065{ 1066 asection *sect; 1067 unsigned int i = 0; 1068 1069 for (sect = abfd->sections; sect != NULL; i++, sect = sect->next) 1070 (*operation) (abfd, sect, user_storage); 1071 1072 if (i != abfd->section_count) /* Debugging */ 1073 abort (); 1074} 1075 1076/* 1077FUNCTION 1078 bfd_set_section_size 1079 1080SYNOPSIS 1081 boolean bfd_set_section_size(bfd *abfd, asection *sec, bfd_size_type val); 1082 1083DESCRIPTION 1084 Set @var{sec} to the size @var{val}. If the operation is 1085 ok, then <<true>> is returned, else <<false>>. 1086 1087 Possible error returns: 1088 o <<bfd_error_invalid_operation>> - 1089 Writing has started to the BFD, so setting the size is invalid. 1090 1091*/ 1092 1093boolean 1094bfd_set_section_size (abfd, ptr, val) 1095 bfd *abfd; 1096 sec_ptr ptr; 1097 bfd_size_type val; 1098{ 1099 /* Once you've started writing to any section you cannot create or change 1100 the size of any others. */ 1101 1102 if (abfd->output_has_begun) 1103 { 1104 bfd_set_error (bfd_error_invalid_operation); 1105 return false; 1106 } 1107 1108 ptr->_cooked_size = val; 1109 ptr->_raw_size = val; 1110 1111 return true; 1112} 1113 1114/* 1115FUNCTION 1116 bfd_set_section_contents 1117 1118SYNOPSIS 1119 boolean bfd_set_section_contents (bfd *abfd, asection *section, 1120 PTR data, file_ptr offset, 1121 bfd_size_type count); 1122 1123DESCRIPTION 1124 Sets the contents of the section @var{section} in BFD 1125 @var{abfd} to the data starting in memory at @var{data}. The 1126 data is written to the output section starting at offset 1127 @var{offset} for @var{count} octets. 1128 1129 Normally <<true>> is returned, else <<false>>. Possible error 1130 returns are: 1131 o <<bfd_error_no_contents>> - 1132 The output section does not have the <<SEC_HAS_CONTENTS>> 1133 attribute, so nothing can be written to it. 1134 o and some more too 1135 1136 This routine is front end to the back end function 1137 <<_bfd_set_section_contents>>. 1138 1139*/ 1140 1141#define bfd_get_section_size_now(abfd,sec) \ 1142(sec->reloc_done \ 1143 ? bfd_get_section_size_after_reloc (sec) \ 1144 : bfd_get_section_size_before_reloc (sec)) 1145 1146boolean 1147bfd_set_section_contents (abfd, section, location, offset, count) 1148 bfd *abfd; 1149 sec_ptr section; 1150 PTR location; 1151 file_ptr offset; 1152 bfd_size_type count; 1153{ 1154 bfd_size_type sz; 1155 1156 if (!(bfd_get_section_flags (abfd, section) & SEC_HAS_CONTENTS)) 1157 { 1158 bfd_set_error (bfd_error_no_contents); 1159 return (false); 1160 } 1161 1162 sz = bfd_get_section_size_now (abfd, section); 1163 if ((bfd_size_type) offset > sz 1164 || count > sz 1165 || offset + count > sz 1166 || count != (size_t) count) 1167 { 1168 bfd_set_error (bfd_error_bad_value); 1169 return false; 1170 } 1171 1172 switch (abfd->direction) 1173 { 1174 case read_direction: 1175 case no_direction: 1176 bfd_set_error (bfd_error_invalid_operation); 1177 return false; 1178 1179 case write_direction: 1180 break; 1181 1182 case both_direction: 1183 /* File is opened for update. `output_has_begun' some time ago when 1184 the file was created. Do not recompute sections sizes or alignments 1185 in _bfd_set_section_content. */ 1186 abfd->output_has_begun = true; 1187 break; 1188 } 1189 1190 /* Record a copy of the data in memory if desired. */ 1191 if (section->contents 1192 && location != section->contents + offset) 1193 memcpy (section->contents + offset, location, (size_t) count); 1194 1195 if (BFD_SEND (abfd, _bfd_set_section_contents, 1196 (abfd, section, location, offset, count))) 1197 { 1198 abfd->output_has_begun = true; 1199 return true; 1200 } 1201 1202 return false; 1203} 1204 1205/* 1206FUNCTION 1207 bfd_get_section_contents 1208 1209SYNOPSIS 1210 boolean bfd_get_section_contents (bfd *abfd, asection *section, 1211 PTR location, file_ptr offset, 1212 bfd_size_type count); 1213 1214DESCRIPTION 1215 Read data from @var{section} in BFD @var{abfd} 1216 into memory starting at @var{location}. The data is read at an 1217 offset of @var{offset} from the start of the input section, 1218 and is read for @var{count} bytes. 1219 1220 If the contents of a constructor with the <<SEC_CONSTRUCTOR>> 1221 flag set are requested or if the section does not have the 1222 <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled 1223 with zeroes. If no errors occur, <<true>> is returned, else 1224 <<false>>. 1225 1226*/ 1227boolean 1228bfd_get_section_contents (abfd, section, location, offset, count) 1229 bfd *abfd; 1230 sec_ptr section; 1231 PTR location; 1232 file_ptr offset; 1233 bfd_size_type count; 1234{ 1235 bfd_size_type sz; 1236 1237 if (section->flags & SEC_CONSTRUCTOR) 1238 { 1239 memset (location, 0, (size_t) count); 1240 return true; 1241 } 1242 1243 /* Even if reloc_done is true, this function reads unrelocated 1244 contents, so we want the raw size. */ 1245 sz = section->_raw_size; 1246 if ((bfd_size_type) offset > sz 1247 || count > sz 1248 || offset + count > sz 1249 || count != (size_t) count) 1250 { 1251 bfd_set_error (bfd_error_bad_value); 1252 return false; 1253 } 1254 1255 if (count == 0) 1256 /* Don't bother. */ 1257 return true; 1258 1259 if ((section->flags & SEC_HAS_CONTENTS) == 0) 1260 { 1261 memset (location, 0, (size_t) count); 1262 return true; 1263 } 1264 1265 if ((section->flags & SEC_IN_MEMORY) != 0) 1266 { 1267 memcpy (location, section->contents + offset, (size_t) count); 1268 return true; 1269 } 1270 1271 return BFD_SEND (abfd, _bfd_get_section_contents, 1272 (abfd, section, location, offset, count)); 1273} 1274 1275/* 1276FUNCTION 1277 bfd_copy_private_section_data 1278 1279SYNOPSIS 1280 boolean bfd_copy_private_section_data (bfd *ibfd, asection *isec, 1281 bfd *obfd, asection *osec); 1282 1283DESCRIPTION 1284 Copy private section information from @var{isec} in the BFD 1285 @var{ibfd} to the section @var{osec} in the BFD @var{obfd}. 1286 Return <<true>> on success, <<false>> on error. Possible error 1287 returns are: 1288 1289 o <<bfd_error_no_memory>> - 1290 Not enough memory exists to create private data for @var{osec}. 1291 1292.#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \ 1293. BFD_SEND (obfd, _bfd_copy_private_section_data, \ 1294. (ibfd, isection, obfd, osection)) 1295*/ 1296 1297/* 1298FUNCTION 1299 _bfd_strip_section_from_output 1300 1301SYNOPSIS 1302 void _bfd_strip_section_from_output 1303 (struct bfd_link_info *info, asection *section); 1304 1305DESCRIPTION 1306 Remove @var{section} from the output. If the output section 1307 becomes empty, remove it from the output bfd. @var{info} may 1308 be NULL; if it is not, it is used to decide whether the output 1309 section is empty. 1310*/ 1311void 1312_bfd_strip_section_from_output (info, s) 1313 struct bfd_link_info *info; 1314 asection *s; 1315{ 1316 asection **spp, *os; 1317 struct bfd_link_order *p, *pp; 1318 boolean keep_os; 1319 1320 /* Excise the input section from the link order. 1321 1322 FIXME: For all calls that I can see to this function, the link 1323 orders have not yet been set up. So why are we checking them? -- 1324 Ian */ 1325 os = s->output_section; 1326 1327 /* Handle a section that wasn't output. */ 1328 if (os == NULL) 1329 return; 1330 1331 for (p = os->link_order_head, pp = NULL; p != NULL; pp = p, p = p->next) 1332 if (p->type == bfd_indirect_link_order 1333 && p->u.indirect.section == s) 1334 { 1335 if (pp) 1336 pp->next = p->next; 1337 else 1338 os->link_order_head = p->next; 1339 if (!p->next) 1340 os->link_order_tail = pp; 1341 break; 1342 } 1343 1344 keep_os = os->link_order_head != NULL; 1345 1346 if (! keep_os && info != NULL) 1347 { 1348 bfd *abfd; 1349 for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link_next) 1350 { 1351 asection *is; 1352 for (is = abfd->sections; is != NULL; is = is->next) 1353 { 1354 if (is != s && is->output_section == os 1355 && (is->flags & SEC_EXCLUDE) == 0) 1356 break; 1357 } 1358 if (is != NULL) 1359 break; 1360 } 1361 if (abfd != NULL) 1362 keep_os = true; 1363 } 1364 1365 /* If the output section is empty, remove it too. Careful about sections 1366 that have been discarded in the link script -- they are mapped to 1367 bfd_abs_section, which has no owner. */ 1368 if (!keep_os && os->owner != NULL) 1369 { 1370 for (spp = &os->owner->sections; *spp; spp = &(*spp)->next) 1371 if (*spp == os) 1372 { 1373 bfd_section_list_remove (os->owner, spp); 1374 os->owner->section_count--; 1375 break; 1376 } 1377 } 1378 1379 s->flags |= SEC_EXCLUDE; 1380} 1381