2000-03-08 H.J. Lu (hjl@gnu.org)
[binutils.git] / bfd / elf32-i386.c
blob90efba8dc9bc824f2e0397f6eb3bb4fedf225d12
1 /* Intel 80386/80486-specific support for 32-bit ELF
2 Copyright 1993, 94-98, 1999 Free Software Foundation, Inc.
4 This file is part of BFD, the Binary File Descriptor library.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
20 #include "bfd.h"
21 #include "sysdep.h"
22 #include "bfdlink.h"
23 #include "libbfd.h"
24 #include "elf-bfd.h"
26 static reloc_howto_type *elf_i386_reloc_type_lookup
27 PARAMS ((bfd *, bfd_reloc_code_real_type));
28 static void elf_i386_info_to_howto
29 PARAMS ((bfd *, arelent *, Elf32_Internal_Rela *));
30 static void elf_i386_info_to_howto_rel
31 PARAMS ((bfd *, arelent *, Elf32_Internal_Rel *));
32 static boolean elf_i386_is_local_label_name PARAMS ((bfd *, const char *));
33 static struct bfd_hash_entry *elf_i386_link_hash_newfunc
34 PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *));
35 static struct bfd_link_hash_table *elf_i386_link_hash_table_create
36 PARAMS ((bfd *));
37 static boolean elf_i386_check_relocs
38 PARAMS ((bfd *, struct bfd_link_info *, asection *,
39 const Elf_Internal_Rela *));
40 static boolean elf_i386_adjust_dynamic_symbol
41 PARAMS ((struct bfd_link_info *, struct elf_link_hash_entry *));
42 static boolean elf_i386_size_dynamic_sections
43 PARAMS ((bfd *, struct bfd_link_info *));
44 static boolean elf_i386_relocate_section
45 PARAMS ((bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *,
46 Elf_Internal_Rela *, Elf_Internal_Sym *, asection **));
47 static boolean elf_i386_finish_dynamic_symbol
48 PARAMS ((bfd *, struct bfd_link_info *, struct elf_link_hash_entry *,
49 Elf_Internal_Sym *));
50 static boolean elf_i386_finish_dynamic_sections
51 PARAMS ((bfd *, struct bfd_link_info *));
53 #define USE_REL 1 /* 386 uses REL relocations instead of RELA */
55 #include "elf/i386.h"
57 static reloc_howto_type elf_howto_table[]=
59 HOWTO(R_386_NONE, 0,0, 0,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_NONE", true,0x00000000,0x00000000,false),
60 HOWTO(R_386_32, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_32", true,0xffffffff,0xffffffff,false),
61 HOWTO(R_386_PC32, 0,2,32,true, 0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_PC32", true,0xffffffff,0xffffffff,true),
62 HOWTO(R_386_GOT32, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_GOT32", true,0xffffffff,0xffffffff,false),
63 HOWTO(R_386_PLT32, 0,2,32,true,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_PLT32", true,0xffffffff,0xffffffff,true),
64 HOWTO(R_386_COPY, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_COPY", true,0xffffffff,0xffffffff,false),
65 HOWTO(R_386_GLOB_DAT, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_GLOB_DAT", true,0xffffffff,0xffffffff,false),
66 HOWTO(R_386_JUMP_SLOT, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_JUMP_SLOT",true,0xffffffff,0xffffffff,false),
67 HOWTO(R_386_RELATIVE, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_RELATIVE", true,0xffffffff,0xffffffff,false),
68 HOWTO(R_386_GOTOFF, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_GOTOFF", true,0xffffffff,0xffffffff,false),
69 HOWTO(R_386_GOTPC, 0,2,32,true,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_GOTPC", true,0xffffffff,0xffffffff,true),
70 EMPTY_HOWTO (11),
71 EMPTY_HOWTO (12),
72 EMPTY_HOWTO (13),
73 EMPTY_HOWTO (14),
74 EMPTY_HOWTO (15),
75 EMPTY_HOWTO (16),
76 EMPTY_HOWTO (17),
77 EMPTY_HOWTO (18),
78 EMPTY_HOWTO (19),
79 /* The remaining relocs are a GNU extension. */
80 HOWTO(R_386_16, 0,1,16,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_16", true,0xffff,0xffff,false),
81 HOWTO(R_386_PC16, 0,1,16,true, 0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_PC16", true,0xffff,0xffff,true),
82 HOWTO(R_386_8, 0,0,8,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_8", true,0xff,0xff,false),
83 HOWTO(R_386_PC8, 0,0,8,true, 0,complain_overflow_signed, bfd_elf_generic_reloc,"R_386_PC8", true,0xff,0xff,true),
86 /* GNU extension to record C++ vtable hierarchy. */
87 static reloc_howto_type elf32_i386_vtinherit_howto =
88 HOWTO (R_386_GNU_VTINHERIT, /* type */
89 0, /* rightshift */
90 2, /* size (0 = byte, 1 = short, 2 = long) */
91 0, /* bitsize */
92 false, /* pc_relative */
93 0, /* bitpos */
94 complain_overflow_dont, /* complain_on_overflow */
95 NULL, /* special_function */
96 "R_386_GNU_VTINHERIT", /* name */
97 false, /* partial_inplace */
98 0, /* src_mask */
99 0, /* dst_mask */
100 false);
102 /* GNU extension to record C++ vtable member usage. */
103 static reloc_howto_type elf32_i386_vtentry_howto =
104 HOWTO (R_386_GNU_VTENTRY, /* type */
105 0, /* rightshift */
106 2, /* size (0 = byte, 1 = short, 2 = long) */
107 0, /* bitsize */
108 false, /* pc_relative */
109 0, /* bitpos */
110 complain_overflow_dont, /* complain_on_overflow */
111 _bfd_elf_rel_vtable_reloc_fn, /* special_function */
112 "R_386_GNU_VTENTRY", /* name */
113 false, /* partial_inplace */
114 0, /* src_mask */
115 0, /* dst_mask */
116 false);
118 #ifdef DEBUG_GEN_RELOC
119 #define TRACE(str) fprintf (stderr, "i386 bfd reloc lookup %d (%s)\n", code, str)
120 #else
121 #define TRACE(str)
122 #endif
124 static reloc_howto_type *
125 elf_i386_reloc_type_lookup (abfd, code)
126 bfd *abfd ATTRIBUTE_UNUSED;
127 bfd_reloc_code_real_type code;
129 switch (code)
131 case BFD_RELOC_NONE:
132 TRACE ("BFD_RELOC_NONE");
133 return &elf_howto_table[ (int)R_386_NONE ];
135 case BFD_RELOC_32:
136 TRACE ("BFD_RELOC_32");
137 return &elf_howto_table[ (int)R_386_32 ];
139 case BFD_RELOC_CTOR:
140 TRACE ("BFD_RELOC_CTOR");
141 return &elf_howto_table[ (int)R_386_32 ];
143 case BFD_RELOC_32_PCREL:
144 TRACE ("BFD_RELOC_PC32");
145 return &elf_howto_table[ (int)R_386_PC32 ];
147 case BFD_RELOC_386_GOT32:
148 TRACE ("BFD_RELOC_386_GOT32");
149 return &elf_howto_table[ (int)R_386_GOT32 ];
151 case BFD_RELOC_386_PLT32:
152 TRACE ("BFD_RELOC_386_PLT32");
153 return &elf_howto_table[ (int)R_386_PLT32 ];
155 case BFD_RELOC_386_COPY:
156 TRACE ("BFD_RELOC_386_COPY");
157 return &elf_howto_table[ (int)R_386_COPY ];
159 case BFD_RELOC_386_GLOB_DAT:
160 TRACE ("BFD_RELOC_386_GLOB_DAT");
161 return &elf_howto_table[ (int)R_386_GLOB_DAT ];
163 case BFD_RELOC_386_JUMP_SLOT:
164 TRACE ("BFD_RELOC_386_JUMP_SLOT");
165 return &elf_howto_table[ (int)R_386_JUMP_SLOT ];
167 case BFD_RELOC_386_RELATIVE:
168 TRACE ("BFD_RELOC_386_RELATIVE");
169 return &elf_howto_table[ (int)R_386_RELATIVE ];
171 case BFD_RELOC_386_GOTOFF:
172 TRACE ("BFD_RELOC_386_GOTOFF");
173 return &elf_howto_table[ (int)R_386_GOTOFF ];
175 case BFD_RELOC_386_GOTPC:
176 TRACE ("BFD_RELOC_386_GOTPC");
177 return &elf_howto_table[ (int)R_386_GOTPC ];
179 /* The remaining relocs are a GNU extension. */
180 case BFD_RELOC_16:
181 TRACE ("BFD_RELOC_16");
182 return &elf_howto_table[(int) R_386_16];
184 case BFD_RELOC_16_PCREL:
185 TRACE ("BFD_RELOC_16_PCREL");
186 return &elf_howto_table[(int) R_386_PC16];
188 case BFD_RELOC_8:
189 TRACE ("BFD_RELOC_8");
190 return &elf_howto_table[(int) R_386_8];
192 case BFD_RELOC_8_PCREL:
193 TRACE ("BFD_RELOC_8_PCREL");
194 return &elf_howto_table[(int) R_386_PC8];
196 case BFD_RELOC_VTABLE_INHERIT:
197 TRACE ("BFD_RELOC_VTABLE_INHERIT");
198 return &elf32_i386_vtinherit_howto;
200 case BFD_RELOC_VTABLE_ENTRY:
201 TRACE ("BFD_RELOC_VTABLE_ENTRY");
202 return &elf32_i386_vtentry_howto;
204 default:
205 break;
208 TRACE ("Unknown");
209 return 0;
212 static void
213 elf_i386_info_to_howto (abfd, cache_ptr, dst)
214 bfd *abfd ATTRIBUTE_UNUSED;
215 arelent *cache_ptr ATTRIBUTE_UNUSED;
216 Elf32_Internal_Rela *dst ATTRIBUTE_UNUSED;
218 abort ();
221 static void
222 elf_i386_info_to_howto_rel (abfd, cache_ptr, dst)
223 bfd *abfd ATTRIBUTE_UNUSED;
224 arelent *cache_ptr;
225 Elf32_Internal_Rel *dst;
227 enum elf_i386_reloc_type type;
229 type = (enum elf_i386_reloc_type) ELF32_R_TYPE (dst->r_info);
230 if (type == R_386_GNU_VTINHERIT)
231 cache_ptr->howto = &elf32_i386_vtinherit_howto;
232 else if (type == R_386_GNU_VTENTRY)
233 cache_ptr->howto = &elf32_i386_vtentry_howto;
234 else if (type < R_386_max
235 && (type < FIRST_INVALID_RELOC || type > LAST_INVALID_RELOC))
236 cache_ptr->howto = &elf_howto_table[(int) type];
237 else
239 (*_bfd_error_handler) (_("%s: invalid relocation type %d"),
240 bfd_get_filename (abfd), (int) type);
241 cache_ptr->howto = &elf_howto_table[(int) R_386_NONE];
245 /* Return whether a symbol name implies a local label. The UnixWare
246 2.1 cc generates temporary symbols that start with .X, so we
247 recognize them here. FIXME: do other SVR4 compilers also use .X?.
248 If so, we should move the .X recognition into
249 _bfd_elf_is_local_label_name. */
251 static boolean
252 elf_i386_is_local_label_name (abfd, name)
253 bfd *abfd;
254 const char *name;
256 if (name[0] == '.' && name[1] == 'X')
257 return true;
259 return _bfd_elf_is_local_label_name (abfd, name);
262 /* Functions for the i386 ELF linker. */
264 /* The name of the dynamic interpreter. This is put in the .interp
265 section. */
267 #define ELF_DYNAMIC_INTERPRETER "/usr/lib/libc.so.1"
269 /* The size in bytes of an entry in the procedure linkage table. */
271 #define PLT_ENTRY_SIZE 16
273 /* The first entry in an absolute procedure linkage table looks like
274 this. See the SVR4 ABI i386 supplement to see how this works. */
276 static const bfd_byte elf_i386_plt0_entry[PLT_ENTRY_SIZE] =
278 0xff, 0x35, /* pushl contents of address */
279 0, 0, 0, 0, /* replaced with address of .got + 4. */
280 0xff, 0x25, /* jmp indirect */
281 0, 0, 0, 0, /* replaced with address of .got + 8. */
282 0, 0, 0, 0 /* pad out to 16 bytes. */
285 /* Subsequent entries in an absolute procedure linkage table look like
286 this. */
288 static const bfd_byte elf_i386_plt_entry[PLT_ENTRY_SIZE] =
290 0xff, 0x25, /* jmp indirect */
291 0, 0, 0, 0, /* replaced with address of this symbol in .got. */
292 0x68, /* pushl immediate */
293 0, 0, 0, 0, /* replaced with offset into relocation table. */
294 0xe9, /* jmp relative */
295 0, 0, 0, 0 /* replaced with offset to start of .plt. */
298 /* The first entry in a PIC procedure linkage table look like this. */
300 static const bfd_byte elf_i386_pic_plt0_entry[PLT_ENTRY_SIZE] =
302 0xff, 0xb3, 4, 0, 0, 0, /* pushl 4(%ebx) */
303 0xff, 0xa3, 8, 0, 0, 0, /* jmp *8(%ebx) */
304 0, 0, 0, 0 /* pad out to 16 bytes. */
307 /* Subsequent entries in a PIC procedure linkage table look like this. */
309 static const bfd_byte elf_i386_pic_plt_entry[PLT_ENTRY_SIZE] =
311 0xff, 0xa3, /* jmp *offset(%ebx) */
312 0, 0, 0, 0, /* replaced with offset of this symbol in .got. */
313 0x68, /* pushl immediate */
314 0, 0, 0, 0, /* replaced with offset into relocation table. */
315 0xe9, /* jmp relative */
316 0, 0, 0, 0 /* replaced with offset to start of .plt. */
319 /* The i386 linker needs to keep track of the number of relocs that it
320 decides to copy in check_relocs for each symbol. This is so that
321 it can discard PC relative relocs if it doesn't need them when
322 linking with -Bsymbolic. We store the information in a field
323 extending the regular ELF linker hash table. */
325 /* This structure keeps track of the number of PC relative relocs we
326 have copied for a given symbol. */
328 struct elf_i386_pcrel_relocs_copied
330 /* Next section. */
331 struct elf_i386_pcrel_relocs_copied *next;
332 /* A section in dynobj. */
333 asection *section;
334 /* Number of relocs copied in this section. */
335 bfd_size_type count;
338 /* i386 ELF linker hash entry. */
340 struct elf_i386_link_hash_entry
342 struct elf_link_hash_entry root;
344 /* Number of PC relative relocs copied for this symbol. */
345 struct elf_i386_pcrel_relocs_copied *pcrel_relocs_copied;
348 /* i386 ELF linker hash table. */
350 struct elf_i386_link_hash_table
352 struct elf_link_hash_table root;
355 /* Declare this now that the above structures are defined. */
357 static boolean elf_i386_discard_copies
358 PARAMS ((struct elf_i386_link_hash_entry *, PTR));
360 /* Traverse an i386 ELF linker hash table. */
362 #define elf_i386_link_hash_traverse(table, func, info) \
363 (elf_link_hash_traverse \
364 (&(table)->root, \
365 (boolean (*) PARAMS ((struct elf_link_hash_entry *, PTR))) (func), \
366 (info)))
368 /* Get the i386 ELF linker hash table from a link_info structure. */
370 #define elf_i386_hash_table(p) \
371 ((struct elf_i386_link_hash_table *) ((p)->hash))
373 /* Create an entry in an i386 ELF linker hash table. */
375 static struct bfd_hash_entry *
376 elf_i386_link_hash_newfunc (entry, table, string)
377 struct bfd_hash_entry *entry;
378 struct bfd_hash_table *table;
379 const char *string;
381 struct elf_i386_link_hash_entry *ret =
382 (struct elf_i386_link_hash_entry *) entry;
384 /* Allocate the structure if it has not already been allocated by a
385 subclass. */
386 if (ret == (struct elf_i386_link_hash_entry *) NULL)
387 ret = ((struct elf_i386_link_hash_entry *)
388 bfd_hash_allocate (table,
389 sizeof (struct elf_i386_link_hash_entry)));
390 if (ret == (struct elf_i386_link_hash_entry *) NULL)
391 return (struct bfd_hash_entry *) ret;
393 /* Call the allocation method of the superclass. */
394 ret = ((struct elf_i386_link_hash_entry *)
395 _bfd_elf_link_hash_newfunc ((struct bfd_hash_entry *) ret,
396 table, string));
397 if (ret != (struct elf_i386_link_hash_entry *) NULL)
399 ret->pcrel_relocs_copied = NULL;
402 return (struct bfd_hash_entry *) ret;
405 /* Create an i386 ELF linker hash table. */
407 static struct bfd_link_hash_table *
408 elf_i386_link_hash_table_create (abfd)
409 bfd *abfd;
411 struct elf_i386_link_hash_table *ret;
413 ret = ((struct elf_i386_link_hash_table *)
414 bfd_alloc (abfd, sizeof (struct elf_i386_link_hash_table)));
415 if (ret == (struct elf_i386_link_hash_table *) NULL)
416 return NULL;
418 if (! _bfd_elf_link_hash_table_init (&ret->root, abfd,
419 elf_i386_link_hash_newfunc))
421 bfd_release (abfd, ret);
422 return NULL;
425 return &ret->root.root;
428 /* Look through the relocs for a section during the first phase, and
429 allocate space in the global offset table or procedure linkage
430 table. */
432 static boolean
433 elf_i386_check_relocs (abfd, info, sec, relocs)
434 bfd *abfd;
435 struct bfd_link_info *info;
436 asection *sec;
437 const Elf_Internal_Rela *relocs;
439 bfd *dynobj;
440 Elf_Internal_Shdr *symtab_hdr;
441 struct elf_link_hash_entry **sym_hashes;
442 bfd_vma *local_got_offsets;
443 const Elf_Internal_Rela *rel;
444 const Elf_Internal_Rela *rel_end;
445 asection *sgot;
446 asection *srelgot;
447 asection *sreloc;
449 if (info->relocateable)
450 return true;
452 dynobj = elf_hash_table (info)->dynobj;
453 symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
454 sym_hashes = elf_sym_hashes (abfd);
455 local_got_offsets = elf_local_got_offsets (abfd);
457 sgot = NULL;
458 srelgot = NULL;
459 sreloc = NULL;
461 rel_end = relocs + sec->reloc_count;
462 for (rel = relocs; rel < rel_end; rel++)
464 unsigned long r_symndx;
465 struct elf_link_hash_entry *h;
467 r_symndx = ELF32_R_SYM (rel->r_info);
469 if (r_symndx < symtab_hdr->sh_info)
470 h = NULL;
471 else
472 h = sym_hashes[r_symndx - symtab_hdr->sh_info];
474 /* Some relocs require a global offset table. */
475 if (dynobj == NULL)
477 switch (ELF32_R_TYPE (rel->r_info))
479 case R_386_GOT32:
480 case R_386_GOTOFF:
481 case R_386_GOTPC:
482 elf_hash_table (info)->dynobj = dynobj = abfd;
483 if (! _bfd_elf_create_got_section (dynobj, info))
484 return false;
485 break;
487 default:
488 break;
492 switch (ELF32_R_TYPE (rel->r_info))
494 case R_386_GOT32:
495 /* This symbol requires a global offset table entry. */
497 if (sgot == NULL)
499 sgot = bfd_get_section_by_name (dynobj, ".got");
500 BFD_ASSERT (sgot != NULL);
503 if (srelgot == NULL
504 && (h != NULL || info->shared))
506 srelgot = bfd_get_section_by_name (dynobj, ".rel.got");
507 if (srelgot == NULL)
509 srelgot = bfd_make_section (dynobj, ".rel.got");
510 if (srelgot == NULL
511 || ! bfd_set_section_flags (dynobj, srelgot,
512 (SEC_ALLOC
513 | SEC_LOAD
514 | SEC_HAS_CONTENTS
515 | SEC_IN_MEMORY
516 | SEC_LINKER_CREATED
517 | SEC_READONLY))
518 || ! bfd_set_section_alignment (dynobj, srelgot, 2))
519 return false;
523 if (h != NULL)
525 if (h->got.offset != (bfd_vma) -1)
527 /* We have already allocated space in the .got. */
528 break;
530 h->got.offset = sgot->_raw_size;
532 /* Make sure this symbol is output as a dynamic symbol. */
533 if (h->dynindx == -1)
535 if (! bfd_elf32_link_record_dynamic_symbol (info, h))
536 return false;
539 srelgot->_raw_size += sizeof (Elf32_External_Rel);
541 else
543 /* This is a global offset table entry for a local
544 symbol. */
545 if (local_got_offsets == NULL)
547 size_t size;
548 register unsigned int i;
550 size = symtab_hdr->sh_info * sizeof (bfd_vma);
551 local_got_offsets = (bfd_vma *) bfd_alloc (abfd, size);
552 if (local_got_offsets == NULL)
553 return false;
554 elf_local_got_offsets (abfd) = local_got_offsets;
555 for (i = 0; i < symtab_hdr->sh_info; i++)
556 local_got_offsets[i] = (bfd_vma) -1;
558 if (local_got_offsets[r_symndx] != (bfd_vma) -1)
560 /* We have already allocated space in the .got. */
561 break;
563 local_got_offsets[r_symndx] = sgot->_raw_size;
565 if (info->shared)
567 /* If we are generating a shared object, we need to
568 output a R_386_RELATIVE reloc so that the dynamic
569 linker can adjust this GOT entry. */
570 srelgot->_raw_size += sizeof (Elf32_External_Rel);
574 sgot->_raw_size += 4;
576 break;
578 case R_386_PLT32:
579 /* This symbol requires a procedure linkage table entry. We
580 actually build the entry in adjust_dynamic_symbol,
581 because this might be a case of linking PIC code which is
582 never referenced by a dynamic object, in which case we
583 don't need to generate a procedure linkage table entry
584 after all. */
586 /* If this is a local symbol, we resolve it directly without
587 creating a procedure linkage table entry. */
588 if (h == NULL)
589 continue;
591 h->elf_link_hash_flags |= ELF_LINK_HASH_NEEDS_PLT;
593 break;
595 case R_386_32:
596 case R_386_PC32:
597 if (h != NULL)
598 h->elf_link_hash_flags |= ELF_LINK_NON_GOT_REF;
600 /* If we are creating a shared library, and this is a reloc
601 against a global symbol, or a non PC relative reloc
602 against a local symbol, then we need to copy the reloc
603 into the shared library. However, if we are linking with
604 -Bsymbolic, we do not need to copy a reloc against a
605 global symbol which is defined in an object we are
606 including in the link (i.e., DEF_REGULAR is set). At
607 this point we have not seen all the input files, so it is
608 possible that DEF_REGULAR is not set now but will be set
609 later (it is never cleared). We account for that
610 possibility below by storing information in the
611 pcrel_relocs_copied field of the hash table entry. */
612 if (info->shared
613 && (sec->flags & SEC_ALLOC) != 0
614 && (ELF32_R_TYPE (rel->r_info) != R_386_PC32
615 || (h != NULL
616 && (! info->symbolic
617 || (h->elf_link_hash_flags
618 & ELF_LINK_HASH_DEF_REGULAR) == 0))))
620 /* When creating a shared object, we must copy these
621 reloc types into the output file. We create a reloc
622 section in dynobj and make room for this reloc. */
623 if (sreloc == NULL)
625 const char *name;
627 name = (bfd_elf_string_from_elf_section
628 (abfd,
629 elf_elfheader (abfd)->e_shstrndx,
630 elf_section_data (sec)->rel_hdr.sh_name));
631 if (name == NULL)
632 return false;
634 BFD_ASSERT (strncmp (name, ".rel", 4) == 0
635 && strcmp (bfd_get_section_name (abfd, sec),
636 name + 4) == 0);
638 sreloc = bfd_get_section_by_name (dynobj, name);
639 if (sreloc == NULL)
641 flagword flags;
643 sreloc = bfd_make_section (dynobj, name);
644 flags = (SEC_HAS_CONTENTS | SEC_READONLY
645 | SEC_IN_MEMORY | SEC_LINKER_CREATED);
646 if ((sec->flags & SEC_ALLOC) != 0)
647 flags |= SEC_ALLOC | SEC_LOAD;
648 if (sreloc == NULL
649 || ! bfd_set_section_flags (dynobj, sreloc, flags)
650 || ! bfd_set_section_alignment (dynobj, sreloc, 2))
651 return false;
655 sreloc->_raw_size += sizeof (Elf32_External_Rel);
657 /* If we are linking with -Bsymbolic, and this is a
658 global symbol, we count the number of PC relative
659 relocations we have entered for this symbol, so that
660 we can discard them again if the symbol is later
661 defined by a regular object. Note that this function
662 is only called if we are using an elf_i386 linker
663 hash table, which means that h is really a pointer to
664 an elf_i386_link_hash_entry. */
665 if (h != NULL && info->symbolic
666 && ELF32_R_TYPE (rel->r_info) == R_386_PC32)
668 struct elf_i386_link_hash_entry *eh;
669 struct elf_i386_pcrel_relocs_copied *p;
671 eh = (struct elf_i386_link_hash_entry *) h;
673 for (p = eh->pcrel_relocs_copied; p != NULL; p = p->next)
674 if (p->section == sreloc)
675 break;
677 if (p == NULL)
679 p = ((struct elf_i386_pcrel_relocs_copied *)
680 bfd_alloc (dynobj, sizeof *p));
681 if (p == NULL)
682 return false;
683 p->next = eh->pcrel_relocs_copied;
684 eh->pcrel_relocs_copied = p;
685 p->section = sreloc;
686 p->count = 0;
689 ++p->count;
693 break;
695 /* This relocation describes the C++ object vtable hierarchy.
696 Reconstruct it for later use during GC. */
697 case R_386_GNU_VTINHERIT:
698 if (!_bfd_elf32_gc_record_vtinherit (abfd, sec, h, rel->r_offset))
699 return false;
700 break;
702 /* This relocation describes which C++ vtable entries are actually
703 used. Record for later use during GC. */
704 case R_386_GNU_VTENTRY:
705 if (!_bfd_elf32_gc_record_vtentry (abfd, sec, h, rel->r_offset))
706 return false;
707 break;
709 default:
710 break;
714 return true;
717 /* Return the section that should be marked against GC for a given
718 relocation. */
720 static asection *
721 elf_i386_gc_mark_hook (abfd, info, rel, h, sym)
722 bfd *abfd;
723 struct bfd_link_info *info ATTRIBUTE_UNUSED;
724 Elf_Internal_Rela *rel;
725 struct elf_link_hash_entry *h;
726 Elf_Internal_Sym *sym;
728 if (h != NULL)
730 switch (ELF32_R_TYPE (rel->r_info))
732 case R_386_GNU_VTINHERIT:
733 case R_386_GNU_VTENTRY:
734 break;
736 default:
737 switch (h->root.type)
739 case bfd_link_hash_defined:
740 case bfd_link_hash_defweak:
741 return h->root.u.def.section;
743 case bfd_link_hash_common:
744 return h->root.u.c.p->section;
746 default:
747 break;
751 else
753 if (!(elf_bad_symtab (abfd)
754 && ELF_ST_BIND (sym->st_info) != STB_LOCAL)
755 && ! ((sym->st_shndx <= 0 || sym->st_shndx >= SHN_LORESERVE)
756 && sym->st_shndx != SHN_COMMON))
758 return bfd_section_from_elf_index (abfd, sym->st_shndx);
762 return NULL;
765 /* Update the got entry reference counts for the section being removed. */
767 static boolean
768 elf_i386_gc_sweep_hook (abfd, info, sec, relocs)
769 bfd *abfd ATTRIBUTE_UNUSED;
770 struct bfd_link_info *info ATTRIBUTE_UNUSED;
771 asection *sec ATTRIBUTE_UNUSED;
772 const Elf_Internal_Rela *relocs ATTRIBUTE_UNUSED;
774 /* ??? It would seem that the existing i386 code does no sort
775 of reference counting or whatnot on its GOT and PLT entries,
776 so it is not possible to garbage collect them at this time. */
778 return true;
781 /* Adjust a symbol defined by a dynamic object and referenced by a
782 regular object. The current definition is in some section of the
783 dynamic object, but we're not including those sections. We have to
784 change the definition to something the rest of the link can
785 understand. */
787 static boolean
788 elf_i386_adjust_dynamic_symbol (info, h)
789 struct bfd_link_info *info;
790 struct elf_link_hash_entry *h;
792 bfd *dynobj;
793 asection *s;
794 unsigned int power_of_two;
796 dynobj = elf_hash_table (info)->dynobj;
798 /* Make sure we know what is going on here. */
799 BFD_ASSERT (dynobj != NULL
800 && ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT)
801 || h->weakdef != NULL
802 || ((h->elf_link_hash_flags
803 & ELF_LINK_HASH_DEF_DYNAMIC) != 0
804 && (h->elf_link_hash_flags
805 & ELF_LINK_HASH_REF_REGULAR) != 0
806 && (h->elf_link_hash_flags
807 & ELF_LINK_HASH_DEF_REGULAR) == 0)));
809 /* If this is a function, put it in the procedure linkage table. We
810 will fill in the contents of the procedure linkage table later,
811 when we know the address of the .got section. */
812 if (h->type == STT_FUNC
813 || (h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) != 0)
815 if (! info->shared
816 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) == 0
817 && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) == 0)
819 /* This case can occur if we saw a PLT32 reloc in an input
820 file, but the symbol was never referred to by a dynamic
821 object. In such a case, we don't actually need to build
822 a procedure linkage table, and we can just do a PC32
823 reloc instead. */
824 BFD_ASSERT ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) != 0);
825 return true;
828 /* Make sure this symbol is output as a dynamic symbol. */
829 if (h->dynindx == -1)
831 if (! bfd_elf32_link_record_dynamic_symbol (info, h))
832 return false;
835 s = bfd_get_section_by_name (dynobj, ".plt");
836 BFD_ASSERT (s != NULL);
838 /* If this is the first .plt entry, make room for the special
839 first entry. */
840 if (s->_raw_size == 0)
841 s->_raw_size += PLT_ENTRY_SIZE;
843 /* If this symbol is not defined in a regular file, and we are
844 not generating a shared library, then set the symbol to this
845 location in the .plt. This is required to make function
846 pointers compare as equal between the normal executable and
847 the shared library. */
848 if (! info->shared
849 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
851 h->root.u.def.section = s;
852 h->root.u.def.value = s->_raw_size;
855 h->plt.offset = s->_raw_size;
857 /* Make room for this entry. */
858 s->_raw_size += PLT_ENTRY_SIZE;
860 /* We also need to make an entry in the .got.plt section, which
861 will be placed in the .got section by the linker script. */
863 s = bfd_get_section_by_name (dynobj, ".got.plt");
864 BFD_ASSERT (s != NULL);
865 s->_raw_size += 4;
867 /* We also need to make an entry in the .rel.plt section. */
869 s = bfd_get_section_by_name (dynobj, ".rel.plt");
870 BFD_ASSERT (s != NULL);
871 s->_raw_size += sizeof (Elf32_External_Rel);
873 return true;
876 /* If this is a weak symbol, and there is a real definition, the
877 processor independent code will have arranged for us to see the
878 real definition first, and we can just use the same value. */
879 if (h->weakdef != NULL)
881 BFD_ASSERT (h->weakdef->root.type == bfd_link_hash_defined
882 || h->weakdef->root.type == bfd_link_hash_defweak);
883 h->root.u.def.section = h->weakdef->root.u.def.section;
884 h->root.u.def.value = h->weakdef->root.u.def.value;
885 return true;
888 /* This is a reference to a symbol defined by a dynamic object which
889 is not a function. */
891 /* If we are creating a shared library, we must presume that the
892 only references to the symbol are via the global offset table.
893 For such cases we need not do anything here; the relocations will
894 be handled correctly by relocate_section. */
895 if (info->shared)
896 return true;
898 /* If there are no references to this symbol that do not use the
899 GOT, we don't need to generate a copy reloc. */
900 if ((h->elf_link_hash_flags & ELF_LINK_NON_GOT_REF) == 0)
901 return true;
903 /* We must allocate the symbol in our .dynbss section, which will
904 become part of the .bss section of the executable. There will be
905 an entry for this symbol in the .dynsym section. The dynamic
906 object will contain position independent code, so all references
907 from the dynamic object to this symbol will go through the global
908 offset table. The dynamic linker will use the .dynsym entry to
909 determine the address it must put in the global offset table, so
910 both the dynamic object and the regular object will refer to the
911 same memory location for the variable. */
913 s = bfd_get_section_by_name (dynobj, ".dynbss");
914 BFD_ASSERT (s != NULL);
916 /* We must generate a R_386_COPY reloc to tell the dynamic linker to
917 copy the initial value out of the dynamic object and into the
918 runtime process image. We need to remember the offset into the
919 .rel.bss section we are going to use. */
920 if ((h->root.u.def.section->flags & SEC_ALLOC) != 0)
922 asection *srel;
924 srel = bfd_get_section_by_name (dynobj, ".rel.bss");
925 BFD_ASSERT (srel != NULL);
926 srel->_raw_size += sizeof (Elf32_External_Rel);
927 h->elf_link_hash_flags |= ELF_LINK_HASH_NEEDS_COPY;
930 /* We need to figure out the alignment required for this symbol. I
931 have no idea how ELF linkers handle this. */
932 power_of_two = bfd_log2 (h->size);
933 if (power_of_two > 3)
934 power_of_two = 3;
936 /* Apply the required alignment. */
937 s->_raw_size = BFD_ALIGN (s->_raw_size,
938 (bfd_size_type) (1 << power_of_two));
939 if (power_of_two > bfd_get_section_alignment (dynobj, s))
941 if (! bfd_set_section_alignment (dynobj, s, power_of_two))
942 return false;
945 /* Define the symbol as being at this point in the section. */
946 h->root.u.def.section = s;
947 h->root.u.def.value = s->_raw_size;
949 /* Increment the section size to make room for the symbol. */
950 s->_raw_size += h->size;
952 return true;
955 /* Set the sizes of the dynamic sections. */
957 static boolean
958 elf_i386_size_dynamic_sections (output_bfd, info)
959 bfd *output_bfd;
960 struct bfd_link_info *info;
962 bfd *dynobj;
963 asection *s;
964 boolean plt;
965 boolean relocs;
966 boolean reltext;
968 dynobj = elf_hash_table (info)->dynobj;
969 BFD_ASSERT (dynobj != NULL);
971 if (elf_hash_table (info)->dynamic_sections_created)
973 /* Set the contents of the .interp section to the interpreter. */
974 if (! info->shared)
976 s = bfd_get_section_by_name (dynobj, ".interp");
977 BFD_ASSERT (s != NULL);
978 s->_raw_size = sizeof ELF_DYNAMIC_INTERPRETER;
979 s->contents = (unsigned char *) ELF_DYNAMIC_INTERPRETER;
982 else
984 /* We may have created entries in the .rel.got section.
985 However, if we are not creating the dynamic sections, we will
986 not actually use these entries. Reset the size of .rel.got,
987 which will cause it to get stripped from the output file
988 below. */
989 s = bfd_get_section_by_name (dynobj, ".rel.got");
990 if (s != NULL)
991 s->_raw_size = 0;
994 /* If this is a -Bsymbolic shared link, then we need to discard all
995 PC relative relocs against symbols defined in a regular object.
996 We allocated space for them in the check_relocs routine, but we
997 will not fill them in in the relocate_section routine. */
998 if (info->shared && info->symbolic)
999 elf_i386_link_hash_traverse (elf_i386_hash_table (info),
1000 elf_i386_discard_copies,
1001 (PTR) NULL);
1003 /* The check_relocs and adjust_dynamic_symbol entry points have
1004 determined the sizes of the various dynamic sections. Allocate
1005 memory for them. */
1006 plt = false;
1007 relocs = false;
1008 reltext = false;
1009 for (s = dynobj->sections; s != NULL; s = s->next)
1011 const char *name;
1012 boolean strip;
1014 if ((s->flags & SEC_LINKER_CREATED) == 0)
1015 continue;
1017 /* It's OK to base decisions on the section name, because none
1018 of the dynobj section names depend upon the input files. */
1019 name = bfd_get_section_name (dynobj, s);
1021 strip = false;
1023 if (strcmp (name, ".plt") == 0)
1025 if (s->_raw_size == 0)
1027 /* Strip this section if we don't need it; see the
1028 comment below. */
1029 strip = true;
1031 else
1033 /* Remember whether there is a PLT. */
1034 plt = true;
1037 else if (strncmp (name, ".rel", 4) == 0)
1039 if (s->_raw_size == 0)
1041 /* If we don't need this section, strip it from the
1042 output file. This is mostly to handle .rel.bss and
1043 .rel.plt. We must create both sections in
1044 create_dynamic_sections, because they must be created
1045 before the linker maps input sections to output
1046 sections. The linker does that before
1047 adjust_dynamic_symbol is called, and it is that
1048 function which decides whether anything needs to go
1049 into these sections. */
1050 strip = true;
1052 else
1054 asection *target;
1056 /* Remember whether there are any reloc sections other
1057 than .rel.plt. */
1058 if (strcmp (name, ".rel.plt") != 0)
1060 const char *outname;
1062 relocs = true;
1064 /* If this relocation section applies to a read only
1065 section, then we probably need a DT_TEXTREL
1066 entry. The entries in the .rel.plt section
1067 really apply to the .got section, which we
1068 created ourselves and so know is not readonly. */
1069 outname = bfd_get_section_name (output_bfd,
1070 s->output_section);
1071 target = bfd_get_section_by_name (output_bfd, outname + 4);
1072 if (target != NULL
1073 && (target->flags & SEC_READONLY) != 0
1074 && (target->flags & SEC_ALLOC) != 0)
1075 reltext = true;
1078 /* We use the reloc_count field as a counter if we need
1079 to copy relocs into the output file. */
1080 s->reloc_count = 0;
1083 else if (strncmp (name, ".got", 4) != 0)
1085 /* It's not one of our sections, so don't allocate space. */
1086 continue;
1089 if (strip)
1091 _bfd_strip_section_from_output (info, s);
1092 continue;
1095 /* Allocate memory for the section contents. */
1096 s->contents = (bfd_byte *) bfd_alloc (dynobj, s->_raw_size);
1097 if (s->contents == NULL && s->_raw_size != 0)
1098 return false;
1101 if (elf_hash_table (info)->dynamic_sections_created)
1103 /* Add some entries to the .dynamic section. We fill in the
1104 values later, in elf_i386_finish_dynamic_sections, but we
1105 must add the entries now so that we get the correct size for
1106 the .dynamic section. The DT_DEBUG entry is filled in by the
1107 dynamic linker and used by the debugger. */
1108 if (! info->shared)
1110 if (! bfd_elf32_add_dynamic_entry (info, DT_DEBUG, 0))
1111 return false;
1114 if (plt)
1116 if (! bfd_elf32_add_dynamic_entry (info, DT_PLTGOT, 0)
1117 || ! bfd_elf32_add_dynamic_entry (info, DT_PLTRELSZ, 0)
1118 || ! bfd_elf32_add_dynamic_entry (info, DT_PLTREL, DT_REL)
1119 || ! bfd_elf32_add_dynamic_entry (info, DT_JMPREL, 0))
1120 return false;
1123 if (relocs)
1125 if (! bfd_elf32_add_dynamic_entry (info, DT_REL, 0)
1126 || ! bfd_elf32_add_dynamic_entry (info, DT_RELSZ, 0)
1127 || ! bfd_elf32_add_dynamic_entry (info, DT_RELENT,
1128 sizeof (Elf32_External_Rel)))
1129 return false;
1132 if (reltext)
1134 if (! bfd_elf32_add_dynamic_entry (info, DT_TEXTREL, 0))
1135 return false;
1139 return true;
1142 /* This function is called via elf_i386_link_hash_traverse if we are
1143 creating a shared object with -Bsymbolic. It discards the space
1144 allocated to copy PC relative relocs against symbols which are
1145 defined in regular objects. We allocated space for them in the
1146 check_relocs routine, but we won't fill them in in the
1147 relocate_section routine. */
1149 /*ARGSUSED*/
1150 static boolean
1151 elf_i386_discard_copies (h, ignore)
1152 struct elf_i386_link_hash_entry *h;
1153 PTR ignore ATTRIBUTE_UNUSED;
1155 struct elf_i386_pcrel_relocs_copied *s;
1157 /* We only discard relocs for symbols defined in a regular object. */
1158 if ((h->root.elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
1159 return true;
1161 for (s = h->pcrel_relocs_copied; s != NULL; s = s->next)
1162 s->section->_raw_size -= s->count * sizeof (Elf32_External_Rel);
1164 return true;
1167 /* Relocate an i386 ELF section. */
1169 static boolean
1170 elf_i386_relocate_section (output_bfd, info, input_bfd, input_section,
1171 contents, relocs, local_syms, local_sections)
1172 bfd *output_bfd;
1173 struct bfd_link_info *info;
1174 bfd *input_bfd;
1175 asection *input_section;
1176 bfd_byte *contents;
1177 Elf_Internal_Rela *relocs;
1178 Elf_Internal_Sym *local_syms;
1179 asection **local_sections;
1181 bfd *dynobj;
1182 Elf_Internal_Shdr *symtab_hdr;
1183 struct elf_link_hash_entry **sym_hashes;
1184 bfd_vma *local_got_offsets;
1185 asection *sgot;
1186 asection *splt;
1187 asection *sreloc;
1188 Elf_Internal_Rela *rel;
1189 Elf_Internal_Rela *relend;
1191 dynobj = elf_hash_table (info)->dynobj;
1192 symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr;
1193 sym_hashes = elf_sym_hashes (input_bfd);
1194 local_got_offsets = elf_local_got_offsets (input_bfd);
1196 sgot = NULL;
1197 splt = NULL;
1198 sreloc = NULL;
1200 rel = relocs;
1201 relend = relocs + input_section->reloc_count;
1202 for (; rel < relend; rel++)
1204 int r_type;
1205 reloc_howto_type *howto;
1206 unsigned long r_symndx;
1207 struct elf_link_hash_entry *h;
1208 Elf_Internal_Sym *sym;
1209 asection *sec;
1210 bfd_vma relocation;
1211 bfd_reloc_status_type r;
1213 r_type = ELF32_R_TYPE (rel->r_info);
1214 if (r_type == R_386_GNU_VTINHERIT
1215 || r_type == R_386_GNU_VTENTRY)
1216 continue;
1217 if (r_type < 0
1218 || r_type >= (int) R_386_max
1219 || (r_type >= (int) FIRST_INVALID_RELOC
1220 && r_type <= (int) LAST_INVALID_RELOC))
1222 bfd_set_error (bfd_error_bad_value);
1223 return false;
1225 howto = elf_howto_table + r_type;
1227 r_symndx = ELF32_R_SYM (rel->r_info);
1229 if (info->relocateable)
1231 /* This is a relocateable link. We don't have to change
1232 anything, unless the reloc is against a section symbol,
1233 in which case we have to adjust according to where the
1234 section symbol winds up in the output section. */
1235 if (r_symndx < symtab_hdr->sh_info)
1237 sym = local_syms + r_symndx;
1238 if (ELF_ST_TYPE (sym->st_info) == STT_SECTION)
1240 bfd_vma val;
1242 sec = local_sections[r_symndx];
1243 val = bfd_get_32 (input_bfd, contents + rel->r_offset);
1244 val += sec->output_offset + sym->st_value;
1245 bfd_put_32 (input_bfd, val, contents + rel->r_offset);
1249 continue;
1252 /* This is a final link. */
1253 h = NULL;
1254 sym = NULL;
1255 sec = NULL;
1256 if (r_symndx < symtab_hdr->sh_info)
1258 sym = local_syms + r_symndx;
1259 sec = local_sections[r_symndx];
1260 relocation = (sec->output_section->vma
1261 + sec->output_offset
1262 + sym->st_value);
1264 else
1266 h = sym_hashes[r_symndx - symtab_hdr->sh_info];
1267 while (h->root.type == bfd_link_hash_indirect
1268 || h->root.type == bfd_link_hash_warning)
1269 h = (struct elf_link_hash_entry *) h->root.u.i.link;
1270 if (h->root.type == bfd_link_hash_defined
1271 || h->root.type == bfd_link_hash_defweak)
1273 sec = h->root.u.def.section;
1274 if (r_type == R_386_GOTPC
1275 || (r_type == R_386_PLT32
1276 && h->plt.offset != (bfd_vma) -1)
1277 || (r_type == R_386_GOT32
1278 && elf_hash_table (info)->dynamic_sections_created
1279 && (! info->shared
1280 || (! info->symbolic && h->dynindx != -1)
1281 || (h->elf_link_hash_flags
1282 & ELF_LINK_HASH_DEF_REGULAR) == 0))
1283 || (info->shared
1284 && ((! info->symbolic && h->dynindx != -1)
1285 || (h->elf_link_hash_flags
1286 & ELF_LINK_HASH_DEF_REGULAR) == 0)
1287 && (r_type == R_386_32
1288 || r_type == R_386_PC32)
1289 && ((input_section->flags & SEC_ALLOC) != 0
1290 /* DWARF will emit R_386_32 relocations in its
1291 sections against symbols defined externally
1292 in shared libraries. We can't do anything
1293 with them here. */
1294 || (input_section->flags & SEC_DEBUGGING) != 0)))
1296 /* In these cases, we don't need the relocation
1297 value. We check specially because in some
1298 obscure cases sec->output_section will be NULL. */
1299 relocation = 0;
1301 else if (sec->output_section == NULL)
1303 (*_bfd_error_handler)
1304 (_("%s: warning: unresolvable relocation against symbol `%s' from %s section"),
1305 bfd_get_filename (input_bfd), h->root.root.string,
1306 bfd_get_section_name (input_bfd, input_section));
1307 relocation = 0;
1309 else
1310 relocation = (h->root.u.def.value
1311 + sec->output_section->vma
1312 + sec->output_offset);
1314 else if (h->root.type == bfd_link_hash_undefweak)
1315 relocation = 0;
1316 else if (info->shared && !info->symbolic && !info->no_undefined)
1317 relocation = 0;
1318 else
1320 if (! ((*info->callbacks->undefined_symbol)
1321 (info, h->root.root.string, input_bfd,
1322 input_section, rel->r_offset,
1323 (!info->shared || info->no_undefined))))
1324 return false;
1325 relocation = 0;
1329 switch (r_type)
1331 case R_386_GOT32:
1332 /* Relocation is to the entry for this symbol in the global
1333 offset table. */
1334 if (sgot == NULL)
1336 sgot = bfd_get_section_by_name (dynobj, ".got");
1337 BFD_ASSERT (sgot != NULL);
1340 if (h != NULL)
1342 bfd_vma off;
1344 off = h->got.offset;
1345 BFD_ASSERT (off != (bfd_vma) -1);
1347 if (! elf_hash_table (info)->dynamic_sections_created
1348 || (info->shared
1349 && (info->symbolic || h->dynindx == -1)
1350 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR)))
1352 /* This is actually a static link, or it is a
1353 -Bsymbolic link and the symbol is defined
1354 locally, or the symbol was forced to be local
1355 because of a version file. We must initialize
1356 this entry in the global offset table. Since the
1357 offset must always be a multiple of 4, we use the
1358 least significant bit to record whether we have
1359 initialized it already.
1361 When doing a dynamic link, we create a .rel.got
1362 relocation entry to initialize the value. This
1363 is done in the finish_dynamic_symbol routine. */
1364 if ((off & 1) != 0)
1365 off &= ~1;
1366 else
1368 bfd_put_32 (output_bfd, relocation,
1369 sgot->contents + off);
1370 h->got.offset |= 1;
1374 relocation = sgot->output_offset + off;
1376 else
1378 bfd_vma off;
1380 BFD_ASSERT (local_got_offsets != NULL
1381 && local_got_offsets[r_symndx] != (bfd_vma) -1);
1383 off = local_got_offsets[r_symndx];
1385 /* The offset must always be a multiple of 4. We use
1386 the least significant bit to record whether we have
1387 already generated the necessary reloc. */
1388 if ((off & 1) != 0)
1389 off &= ~1;
1390 else
1392 bfd_put_32 (output_bfd, relocation, sgot->contents + off);
1394 if (info->shared)
1396 asection *srelgot;
1397 Elf_Internal_Rel outrel;
1399 srelgot = bfd_get_section_by_name (dynobj, ".rel.got");
1400 BFD_ASSERT (srelgot != NULL);
1402 outrel.r_offset = (sgot->output_section->vma
1403 + sgot->output_offset
1404 + off);
1405 outrel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
1406 bfd_elf32_swap_reloc_out (output_bfd, &outrel,
1407 (((Elf32_External_Rel *)
1408 srelgot->contents)
1409 + srelgot->reloc_count));
1410 ++srelgot->reloc_count;
1413 local_got_offsets[r_symndx] |= 1;
1416 relocation = sgot->output_offset + off;
1419 break;
1421 case R_386_GOTOFF:
1422 /* Relocation is relative to the start of the global offset
1423 table. */
1425 if (sgot == NULL)
1427 sgot = bfd_get_section_by_name (dynobj, ".got");
1428 BFD_ASSERT (sgot != NULL);
1431 /* Note that sgot->output_offset is not involved in this
1432 calculation. We always want the start of .got. If we
1433 defined _GLOBAL_OFFSET_TABLE in a different way, as is
1434 permitted by the ABI, we might have to change this
1435 calculation. */
1436 relocation -= sgot->output_section->vma;
1438 break;
1440 case R_386_GOTPC:
1441 /* Use global offset table as symbol value. */
1443 if (sgot == NULL)
1445 sgot = bfd_get_section_by_name (dynobj, ".got");
1446 BFD_ASSERT (sgot != NULL);
1449 relocation = sgot->output_section->vma;
1451 break;
1453 case R_386_PLT32:
1454 /* Relocation is to the entry for this symbol in the
1455 procedure linkage table. */
1457 /* Resolve a PLT32 reloc again a local symbol directly,
1458 without using the procedure linkage table. */
1459 if (h == NULL)
1460 break;
1462 if (h->plt.offset == (bfd_vma) -1)
1464 /* We didn't make a PLT entry for this symbol. This
1465 happens when statically linking PIC code, or when
1466 using -Bsymbolic. */
1467 break;
1470 if (splt == NULL)
1472 splt = bfd_get_section_by_name (dynobj, ".plt");
1473 BFD_ASSERT (splt != NULL);
1476 relocation = (splt->output_section->vma
1477 + splt->output_offset
1478 + h->plt.offset);
1480 break;
1482 case R_386_32:
1483 case R_386_PC32:
1484 if (info->shared
1485 && (input_section->flags & SEC_ALLOC) != 0
1486 && (r_type != R_386_PC32
1487 || (h != NULL
1488 && h->dynindx != -1
1489 && (! info->symbolic
1490 || (h->elf_link_hash_flags
1491 & ELF_LINK_HASH_DEF_REGULAR) == 0))))
1493 Elf_Internal_Rel outrel;
1494 boolean skip, relocate;
1496 /* When generating a shared object, these relocations
1497 are copied into the output file to be resolved at run
1498 time. */
1500 if (sreloc == NULL)
1502 const char *name;
1504 name = (bfd_elf_string_from_elf_section
1505 (input_bfd,
1506 elf_elfheader (input_bfd)->e_shstrndx,
1507 elf_section_data (input_section)->rel_hdr.sh_name));
1508 if (name == NULL)
1509 return false;
1511 BFD_ASSERT (strncmp (name, ".rel", 4) == 0
1512 && strcmp (bfd_get_section_name (input_bfd,
1513 input_section),
1514 name + 4) == 0);
1516 sreloc = bfd_get_section_by_name (dynobj, name);
1517 BFD_ASSERT (sreloc != NULL);
1520 skip = false;
1522 if (elf_section_data (input_section)->stab_info == NULL)
1523 outrel.r_offset = rel->r_offset;
1524 else
1526 bfd_vma off;
1528 off = (_bfd_stab_section_offset
1529 (output_bfd, &elf_hash_table (info)->stab_info,
1530 input_section,
1531 &elf_section_data (input_section)->stab_info,
1532 rel->r_offset));
1533 if (off == (bfd_vma) -1)
1534 skip = true;
1535 outrel.r_offset = off;
1538 outrel.r_offset += (input_section->output_section->vma
1539 + input_section->output_offset);
1541 if (skip)
1543 memset (&outrel, 0, sizeof outrel);
1544 relocate = false;
1546 else if (r_type == R_386_PC32)
1548 BFD_ASSERT (h != NULL && h->dynindx != -1);
1549 relocate = false;
1550 outrel.r_info = ELF32_R_INFO (h->dynindx, R_386_PC32);
1552 else
1554 /* h->dynindx may be -1 if this symbol was marked to
1555 become local. */
1556 if (h == NULL
1557 || ((info->symbolic || h->dynindx == -1)
1558 && (h->elf_link_hash_flags
1559 & ELF_LINK_HASH_DEF_REGULAR) != 0))
1561 relocate = true;
1562 outrel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
1564 else
1566 BFD_ASSERT (h->dynindx != -1);
1567 relocate = false;
1568 outrel.r_info = ELF32_R_INFO (h->dynindx, R_386_32);
1572 bfd_elf32_swap_reloc_out (output_bfd, &outrel,
1573 (((Elf32_External_Rel *)
1574 sreloc->contents)
1575 + sreloc->reloc_count));
1576 ++sreloc->reloc_count;
1578 /* If this reloc is against an external symbol, we do
1579 not want to fiddle with the addend. Otherwise, we
1580 need to include the symbol value so that it becomes
1581 an addend for the dynamic reloc. */
1582 if (! relocate)
1583 continue;
1586 break;
1588 default:
1589 break;
1592 r = _bfd_final_link_relocate (howto, input_bfd, input_section,
1593 contents, rel->r_offset,
1594 relocation, (bfd_vma) 0);
1596 if (r != bfd_reloc_ok)
1598 switch (r)
1600 default:
1601 case bfd_reloc_outofrange:
1602 abort ();
1603 case bfd_reloc_overflow:
1605 const char *name;
1607 if (h != NULL)
1608 name = h->root.root.string;
1609 else
1611 name = bfd_elf_string_from_elf_section (input_bfd,
1612 symtab_hdr->sh_link,
1613 sym->st_name);
1614 if (name == NULL)
1615 return false;
1616 if (*name == '\0')
1617 name = bfd_section_name (input_bfd, sec);
1619 if (! ((*info->callbacks->reloc_overflow)
1620 (info, name, howto->name, (bfd_vma) 0,
1621 input_bfd, input_section, rel->r_offset)))
1622 return false;
1624 break;
1629 return true;
1632 /* Finish up dynamic symbol handling. We set the contents of various
1633 dynamic sections here. */
1635 static boolean
1636 elf_i386_finish_dynamic_symbol (output_bfd, info, h, sym)
1637 bfd *output_bfd;
1638 struct bfd_link_info *info;
1639 struct elf_link_hash_entry *h;
1640 Elf_Internal_Sym *sym;
1642 bfd *dynobj;
1644 dynobj = elf_hash_table (info)->dynobj;
1646 if (h->plt.offset != (bfd_vma) -1)
1648 asection *splt;
1649 asection *sgot;
1650 asection *srel;
1651 bfd_vma plt_index;
1652 bfd_vma got_offset;
1653 Elf_Internal_Rel rel;
1655 /* This symbol has an entry in the procedure linkage table. Set
1656 it up. */
1658 BFD_ASSERT (h->dynindx != -1);
1660 splt = bfd_get_section_by_name (dynobj, ".plt");
1661 sgot = bfd_get_section_by_name (dynobj, ".got.plt");
1662 srel = bfd_get_section_by_name (dynobj, ".rel.plt");
1663 BFD_ASSERT (splt != NULL && sgot != NULL && srel != NULL);
1665 /* Get the index in the procedure linkage table which
1666 corresponds to this symbol. This is the index of this symbol
1667 in all the symbols for which we are making plt entries. The
1668 first entry in the procedure linkage table is reserved. */
1669 plt_index = h->plt.offset / PLT_ENTRY_SIZE - 1;
1671 /* Get the offset into the .got table of the entry that
1672 corresponds to this function. Each .got entry is 4 bytes.
1673 The first three are reserved. */
1674 got_offset = (plt_index + 3) * 4;
1676 /* Fill in the entry in the procedure linkage table. */
1677 if (! info->shared)
1679 memcpy (splt->contents + h->plt.offset, elf_i386_plt_entry,
1680 PLT_ENTRY_SIZE);
1681 bfd_put_32 (output_bfd,
1682 (sgot->output_section->vma
1683 + sgot->output_offset
1684 + got_offset),
1685 splt->contents + h->plt.offset + 2);
1687 else
1689 memcpy (splt->contents + h->plt.offset, elf_i386_pic_plt_entry,
1690 PLT_ENTRY_SIZE);
1691 bfd_put_32 (output_bfd, got_offset,
1692 splt->contents + h->plt.offset + 2);
1695 bfd_put_32 (output_bfd, plt_index * sizeof (Elf32_External_Rel),
1696 splt->contents + h->plt.offset + 7);
1697 bfd_put_32 (output_bfd, - (h->plt.offset + PLT_ENTRY_SIZE),
1698 splt->contents + h->plt.offset + 12);
1700 /* Fill in the entry in the global offset table. */
1701 bfd_put_32 (output_bfd,
1702 (splt->output_section->vma
1703 + splt->output_offset
1704 + h->plt.offset
1705 + 6),
1706 sgot->contents + got_offset);
1708 /* Fill in the entry in the .rel.plt section. */
1709 rel.r_offset = (sgot->output_section->vma
1710 + sgot->output_offset
1711 + got_offset);
1712 rel.r_info = ELF32_R_INFO (h->dynindx, R_386_JUMP_SLOT);
1713 bfd_elf32_swap_reloc_out (output_bfd, &rel,
1714 ((Elf32_External_Rel *) srel->contents
1715 + plt_index));
1717 if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
1719 /* Mark the symbol as undefined, rather than as defined in
1720 the .plt section. Leave the value alone. */
1721 sym->st_shndx = SHN_UNDEF;
1725 if (h->got.offset != (bfd_vma) -1)
1727 asection *sgot;
1728 asection *srel;
1729 Elf_Internal_Rel rel;
1731 /* This symbol has an entry in the global offset table. Set it
1732 up. */
1734 sgot = bfd_get_section_by_name (dynobj, ".got");
1735 srel = bfd_get_section_by_name (dynobj, ".rel.got");
1736 BFD_ASSERT (sgot != NULL && srel != NULL);
1738 rel.r_offset = (sgot->output_section->vma
1739 + sgot->output_offset
1740 + (h->got.offset &~ 1));
1742 /* If this is a -Bsymbolic link, and the symbol is defined
1743 locally, we just want to emit a RELATIVE reloc. Likewise if
1744 the symbol was forced to be local because of a version file.
1745 The entry in the global offset table will already have been
1746 initialized in the relocate_section function. */
1747 if (info->shared
1748 && (info->symbolic || h->dynindx == -1)
1749 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR))
1750 rel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
1751 else
1753 bfd_put_32 (output_bfd, (bfd_vma) 0, sgot->contents + h->got.offset);
1754 rel.r_info = ELF32_R_INFO (h->dynindx, R_386_GLOB_DAT);
1757 bfd_elf32_swap_reloc_out (output_bfd, &rel,
1758 ((Elf32_External_Rel *) srel->contents
1759 + srel->reloc_count));
1760 ++srel->reloc_count;
1763 if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_COPY) != 0)
1765 asection *s;
1766 Elf_Internal_Rel rel;
1768 /* This symbol needs a copy reloc. Set it up. */
1770 BFD_ASSERT (h->dynindx != -1
1771 && (h->root.type == bfd_link_hash_defined
1772 || h->root.type == bfd_link_hash_defweak));
1774 s = bfd_get_section_by_name (h->root.u.def.section->owner,
1775 ".rel.bss");
1776 BFD_ASSERT (s != NULL);
1778 rel.r_offset = (h->root.u.def.value
1779 + h->root.u.def.section->output_section->vma
1780 + h->root.u.def.section->output_offset);
1781 rel.r_info = ELF32_R_INFO (h->dynindx, R_386_COPY);
1782 bfd_elf32_swap_reloc_out (output_bfd, &rel,
1783 ((Elf32_External_Rel *) s->contents
1784 + s->reloc_count));
1785 ++s->reloc_count;
1788 /* Mark _DYNAMIC and _GLOBAL_OFFSET_TABLE_ as absolute. */
1789 if (strcmp (h->root.root.string, "_DYNAMIC") == 0
1790 || strcmp (h->root.root.string, "_GLOBAL_OFFSET_TABLE_") == 0)
1791 sym->st_shndx = SHN_ABS;
1793 return true;
1796 /* Finish up the dynamic sections. */
1798 static boolean
1799 elf_i386_finish_dynamic_sections (output_bfd, info)
1800 bfd *output_bfd;
1801 struct bfd_link_info *info;
1803 bfd *dynobj;
1804 asection *sgot;
1805 asection *sdyn;
1807 dynobj = elf_hash_table (info)->dynobj;
1809 sgot = bfd_get_section_by_name (dynobj, ".got.plt");
1810 BFD_ASSERT (sgot != NULL);
1811 sdyn = bfd_get_section_by_name (dynobj, ".dynamic");
1813 if (elf_hash_table (info)->dynamic_sections_created)
1815 asection *splt;
1816 Elf32_External_Dyn *dyncon, *dynconend;
1818 BFD_ASSERT (sdyn != NULL);
1820 dyncon = (Elf32_External_Dyn *) sdyn->contents;
1821 dynconend = (Elf32_External_Dyn *) (sdyn->contents + sdyn->_raw_size);
1822 for (; dyncon < dynconend; dyncon++)
1824 Elf_Internal_Dyn dyn;
1825 const char *name;
1826 asection *s;
1828 bfd_elf32_swap_dyn_in (dynobj, dyncon, &dyn);
1830 switch (dyn.d_tag)
1832 default:
1833 break;
1835 case DT_PLTGOT:
1836 name = ".got";
1837 goto get_vma;
1838 case DT_JMPREL:
1839 name = ".rel.plt";
1840 get_vma:
1841 s = bfd_get_section_by_name (output_bfd, name);
1842 BFD_ASSERT (s != NULL);
1843 dyn.d_un.d_ptr = s->vma;
1844 bfd_elf32_swap_dyn_out (output_bfd, &dyn, dyncon);
1845 break;
1847 case DT_PLTRELSZ:
1848 s = bfd_get_section_by_name (output_bfd, ".rel.plt");
1849 BFD_ASSERT (s != NULL);
1850 if (s->_cooked_size != 0)
1851 dyn.d_un.d_val = s->_cooked_size;
1852 else
1853 dyn.d_un.d_val = s->_raw_size;
1854 bfd_elf32_swap_dyn_out (output_bfd, &dyn, dyncon);
1855 break;
1857 case DT_RELSZ:
1858 /* My reading of the SVR4 ABI indicates that the
1859 procedure linkage table relocs (DT_JMPREL) should be
1860 included in the overall relocs (DT_REL). This is
1861 what Solaris does. However, UnixWare can not handle
1862 that case. Therefore, we override the DT_RELSZ entry
1863 here to make it not include the JMPREL relocs. Since
1864 the linker script arranges for .rel.plt to follow all
1865 other relocation sections, we don't have to worry
1866 about changing the DT_REL entry. */
1867 s = bfd_get_section_by_name (output_bfd, ".rel.plt");
1868 if (s != NULL)
1870 if (s->_cooked_size != 0)
1871 dyn.d_un.d_val -= s->_cooked_size;
1872 else
1873 dyn.d_un.d_val -= s->_raw_size;
1875 bfd_elf32_swap_dyn_out (output_bfd, &dyn, dyncon);
1876 break;
1880 /* Fill in the first entry in the procedure linkage table. */
1881 splt = bfd_get_section_by_name (dynobj, ".plt");
1882 if (splt && splt->_raw_size > 0)
1884 if (info->shared)
1885 memcpy (splt->contents, elf_i386_pic_plt0_entry, PLT_ENTRY_SIZE);
1886 else
1888 memcpy (splt->contents, elf_i386_plt0_entry, PLT_ENTRY_SIZE);
1889 bfd_put_32 (output_bfd,
1890 sgot->output_section->vma + sgot->output_offset + 4,
1891 splt->contents + 2);
1892 bfd_put_32 (output_bfd,
1893 sgot->output_section->vma + sgot->output_offset + 8,
1894 splt->contents + 8);
1897 /* UnixWare sets the entsize of .plt to 4, although that doesn't
1898 really seem like the right value. */
1899 elf_section_data (splt->output_section)->this_hdr.sh_entsize = 4;
1903 /* Fill in the first three entries in the global offset table. */
1904 if (sgot->_raw_size > 0)
1906 if (sdyn == NULL)
1907 bfd_put_32 (output_bfd, (bfd_vma) 0, sgot->contents);
1908 else
1909 bfd_put_32 (output_bfd,
1910 sdyn->output_section->vma + sdyn->output_offset,
1911 sgot->contents);
1912 bfd_put_32 (output_bfd, (bfd_vma) 0, sgot->contents + 4);
1913 bfd_put_32 (output_bfd, (bfd_vma) 0, sgot->contents + 8);
1916 elf_section_data (sgot->output_section)->this_hdr.sh_entsize = 4;
1918 return true;
1921 #define TARGET_LITTLE_SYM bfd_elf32_i386_vec
1922 #define TARGET_LITTLE_NAME "elf32-i386"
1923 #define ELF_ARCH bfd_arch_i386
1924 #define ELF_MACHINE_CODE EM_386
1925 #define ELF_MAXPAGESIZE 0x1000
1926 #define elf_info_to_howto elf_i386_info_to_howto
1927 #define elf_info_to_howto_rel elf_i386_info_to_howto_rel
1928 #define bfd_elf32_bfd_reloc_type_lookup elf_i386_reloc_type_lookup
1929 #define bfd_elf32_bfd_is_local_label_name \
1930 elf_i386_is_local_label_name
1931 #define elf_backend_create_dynamic_sections \
1932 _bfd_elf_create_dynamic_sections
1933 #define bfd_elf32_bfd_link_hash_table_create \
1934 elf_i386_link_hash_table_create
1935 #define elf_backend_check_relocs elf_i386_check_relocs
1936 #define elf_backend_adjust_dynamic_symbol \
1937 elf_i386_adjust_dynamic_symbol
1938 #define elf_backend_size_dynamic_sections \
1939 elf_i386_size_dynamic_sections
1940 #define elf_backend_relocate_section elf_i386_relocate_section
1941 #define elf_backend_finish_dynamic_symbol \
1942 elf_i386_finish_dynamic_symbol
1943 #define elf_backend_finish_dynamic_sections \
1944 elf_i386_finish_dynamic_sections
1945 #define elf_backend_gc_mark_hook elf_i386_gc_mark_hook
1946 #define elf_backend_gc_sweep_hook elf_i386_gc_sweep_hook
1948 #define elf_backend_can_gc_sections 1
1949 #define elf_backend_want_got_plt 1
1950 #define elf_backend_plt_readonly 1
1951 #define elf_backend_want_plt_sym 0
1952 #define elf_backend_got_header_size 12
1953 #define elf_backend_plt_header_size PLT_ENTRY_SIZE
1955 #include "elf32-target.h"