1 /* Intel 80386/80486-specific support for 32-bit ELF
2 Copyright 1993, 1994, 1995 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., 675 Mass Ave, Cambridge, MA 02139, USA. */
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_create_dynamic_sections
33 PARAMS ((bfd *, struct bfd_link_info *));
34 static boolean elf_i386_create_got_section
35 PARAMS ((bfd *, struct bfd_link_info *));
36 static boolean elf_i386_check_relocs
37 PARAMS ((bfd *, struct bfd_link_info *, asection *,
38 const Elf_Internal_Rela *));
39 static boolean elf_i386_adjust_dynamic_symbol
40 PARAMS ((struct bfd_link_info *, struct elf_link_hash_entry *));
41 static boolean elf_i386_size_dynamic_sections
42 PARAMS ((bfd *, struct bfd_link_info *));
43 static boolean elf_i386_relocate_section
44 PARAMS ((bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *,
45 Elf_Internal_Rela *, Elf_Internal_Sym *, asection **));
46 static boolean elf_i386_finish_dynamic_symbol
47 PARAMS ((bfd *, struct bfd_link_info *, struct elf_link_hash_entry *,
49 static boolean elf_i386_finish_dynamic_sections
50 PARAMS ((bfd *, struct bfd_link_info *));
52 #define USE_REL 1 /* 386 uses REL relocations instead of RELA */
71 static CONST char *CONST reloc_type_names[] =
87 static reloc_howto_type elf_howto_table[]=
89 HOWTO(R_386_NONE, 0,0, 0,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_NONE", true,0x00000000,0x00000000,false),
90 HOWTO(R_386_32, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_32", true,0xffffffff,0xffffffff,false),
91 HOWTO(R_386_PC32, 0,2,32,true, 0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_PC32", true,0xffffffff,0xffffffff,true),
92 HOWTO(R_386_GOT32, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_GOT32", true,0xffffffff,0xffffffff,false),
93 HOWTO(R_386_PLT32, 0,2,32,true,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_PLT32", true,0xffffffff,0xffffffff,true),
94 HOWTO(R_386_COPY, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_COPY", true,0xffffffff,0xffffffff,false),
95 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),
96 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),
97 HOWTO(R_386_RELATIVE, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_RELATIVE", true,0xffffffff,0xffffffff,false),
98 HOWTO(R_386_GOTOFF, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_GOTOFF", true,0xffffffff,0xffffffff,false),
99 HOWTO(R_386_GOTPC, 0,2,32,true,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_GOTPC", true,0xffffffff,0xffffffff,true),
102 #ifdef DEBUG_GEN_RELOC
103 #define TRACE(str) fprintf (stderr, "i386 bfd reloc lookup %d (%s)\n", code, str)
108 static reloc_howto_type *
109 elf_i386_reloc_type_lookup (abfd, code)
111 bfd_reloc_code_real_type code;
116 TRACE ("BFD_RELOC_NONE");
117 return &elf_howto_table[ (int)R_386_NONE ];
120 TRACE ("BFD_RELOC_32");
121 return &elf_howto_table[ (int)R_386_32 ];
123 case BFD_RELOC_32_PCREL:
124 TRACE ("BFD_RELOC_PC32");
125 return &elf_howto_table[ (int)R_386_PC32 ];
127 case BFD_RELOC_386_GOT32:
128 TRACE ("BFD_RELOC_386_GOT32");
129 return &elf_howto_table[ (int)R_386_GOT32 ];
131 case BFD_RELOC_386_PLT32:
132 TRACE ("BFD_RELOC_386_PLT32");
133 return &elf_howto_table[ (int)R_386_PLT32 ];
135 case BFD_RELOC_386_COPY:
136 TRACE ("BFD_RELOC_386_COPY");
137 return &elf_howto_table[ (int)R_386_COPY ];
139 case BFD_RELOC_386_GLOB_DAT:
140 TRACE ("BFD_RELOC_386_GLOB_DAT");
141 return &elf_howto_table[ (int)R_386_GLOB_DAT ];
143 case BFD_RELOC_386_JUMP_SLOT:
144 TRACE ("BFD_RELOC_386_JUMP_SLOT");
145 return &elf_howto_table[ (int)R_386_JUMP_SLOT ];
147 case BFD_RELOC_386_RELATIVE:
148 TRACE ("BFD_RELOC_386_RELATIVE");
149 return &elf_howto_table[ (int)R_386_RELATIVE ];
151 case BFD_RELOC_386_GOTOFF:
152 TRACE ("BFD_RELOC_386_GOTOFF");
153 return &elf_howto_table[ (int)R_386_GOTOFF ];
155 case BFD_RELOC_386_GOTPC:
156 TRACE ("BFD_RELOC_386_GOTPC");
157 return &elf_howto_table[ (int)R_386_GOTPC ];
168 elf_i386_info_to_howto (abfd, cache_ptr, dst)
171 Elf32_Internal_Rela *dst;
173 BFD_ASSERT (ELF32_R_TYPE(dst->r_info) < (unsigned int) R_386_max);
175 cache_ptr->howto = &elf_howto_table[ELF32_R_TYPE(dst->r_info)];
179 elf_i386_info_to_howto_rel (abfd, cache_ptr, dst)
182 Elf32_Internal_Rel *dst;
184 BFD_ASSERT (ELF32_R_TYPE(dst->r_info) < (unsigned int) R_386_max);
186 cache_ptr->howto = &elf_howto_table[ELF32_R_TYPE(dst->r_info)];
189 /* Functions for the i386 ELF linker. */
191 /* The name of the dynamic interpreter. This is put in the .interp
194 #define ELF_DYNAMIC_INTERPRETER "/usr/lib/libc.so.1"
196 /* The size in bytes of an entry in the procedure linkage table. */
198 #define PLT_ENTRY_SIZE 16
200 /* The first entry in an absolute procedure linkage table looks like
201 this. See the SVR4 ABI i386 supplement to see how this works. */
203 static const bfd_byte elf_i386_plt0_entry[PLT_ENTRY_SIZE] =
205 0xff, 0x35, /* pushl contents of address */
206 0, 0, 0, 0, /* replaced with address of .got + 4. */
207 0xff, 0x25, /* jmp indirect */
208 0, 0, 0, 0, /* replaced with address of .got + 8. */
209 0, 0, 0, 0 /* pad out to 16 bytes. */
212 /* Subsequent entries in an absolute procedure linkage table look like
215 static const bfd_byte elf_i386_plt_entry[PLT_ENTRY_SIZE] =
217 0xff, 0x25, /* jmp indirect */
218 0, 0, 0, 0, /* replaced with address of this symbol in .got. */
219 0x68, /* pushl immediate */
220 0, 0, 0, 0, /* replaced with offset into relocation table. */
221 0xe9, /* jmp relative */
222 0, 0, 0, 0 /* replaced with offset to start of .plt. */
225 /* The first entry in a PIC procedure linkage table look like this. */
227 static const bfd_byte elf_i386_pic_plt0_entry[PLT_ENTRY_SIZE] =
229 0xff, 0xb3, 4, 0, 0, 0, /* pushl 4(%ebx) */
230 0xff, 0xa3, 8, 0, 0, 0, /* jmp *8(%ebx) */
231 0, 0, 0, 0 /* pad out to 16 bytes. */
234 /* Subsequent entries in a PIC procedure linkage table look like this. */
236 static const bfd_byte elf_i386_pic_plt_entry[PLT_ENTRY_SIZE] =
238 0xff, 0xa3, /* jmp *offset(%ebx) */
239 0, 0, 0, 0, /* replaced with offset of this symbol in .got. */
240 0x68, /* pushl immediate */
241 0, 0, 0, 0, /* replaced with offset into relocation table. */
242 0xe9, /* jmp relative */
243 0, 0, 0, 0 /* replaced with offset to start of .plt. */
246 /* Create dynamic sections when linking against a dynamic object. */
249 elf_i386_create_dynamic_sections (abfd, info)
251 struct bfd_link_info *info;
254 register asection *s;
256 /* We need to create .plt, .rel.plt, .got, .got.plt, .dynbss, and
257 .rel.bss sections. */
259 flags = SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY;
261 s = bfd_make_section (abfd, ".plt");
263 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY | SEC_CODE)
264 || ! bfd_set_section_alignment (abfd, s, 2))
267 s = bfd_make_section (abfd, ".rel.plt");
269 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
270 || ! bfd_set_section_alignment (abfd, s, 2))
273 if (! elf_i386_create_got_section (abfd, info))
276 /* The .dynbss section is a place to put symbols which are defined
277 by dynamic objects, are referenced by regular objects, and are
278 not functions. We must allocate space for them in the process
279 image and use a R_386_COPY reloc to tell the dynamic linker to
280 initialize them at run time. The linker script puts the .dynbss
281 section into the .bss section of the final image. */
282 s = bfd_make_section (abfd, ".dynbss");
284 || ! bfd_set_section_flags (abfd, s, SEC_ALLOC))
287 /* The .rel.bss section holds copy relocs. This section is not
288 normally needed. We need to create it here, though, so that the
289 linker will map it to an output section. We can't just create it
290 only if we need it, because we will not know whether we need it
291 until we have seen all the input files, and the first time the
292 main linker code calls BFD after examining all the input files
293 (size_dynamic_sections) the input sections have already been
294 mapped to the output sections. If the section turns out not to
295 be needed, we can discard it later. We will never need this
296 section when generating a shared object, since they do not use
300 s = bfd_make_section (abfd, ".rel.bss");
302 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
303 || ! bfd_set_section_alignment (abfd, s, 2))
310 /* Create the .got section to hold the global offset table, and the
311 .got.plt section to hold procedure linkage table GOT entries. The
312 linker script will put .got.plt into the output .got section. */
315 elf_i386_create_got_section (abfd, info)
317 struct bfd_link_info *info;
320 register asection *s;
321 struct elf_link_hash_entry *h;
323 /* This function may be called more than once. */
324 if (bfd_get_section_by_name (abfd, ".got") != NULL)
327 flags = SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY;
329 s = bfd_make_section (abfd, ".got");
331 || ! bfd_set_section_flags (abfd, s, flags)
332 || ! bfd_set_section_alignment (abfd, s, 2))
335 s = bfd_make_section (abfd, ".got.plt");
337 || ! bfd_set_section_flags (abfd, s, flags)
338 || ! bfd_set_section_alignment (abfd, s, 2))
341 /* Define the symbol _GLOBAL_OFFSET_TABLE_ at the start of the
342 .got.plt section, which will be placed at the start of the output
343 .got section. We don't do this in the linker script because we
344 don't want to define the symbol if we are not creating a global
347 if (! (_bfd_generic_link_add_one_symbol
348 (info, abfd, "_GLOBAL_OFFSET_TABLE_", BSF_GLOBAL, s, (bfd_vma) 0,
349 (const char *) NULL, false, get_elf_backend_data (abfd)->collect,
350 (struct bfd_link_hash_entry **) &h)))
352 h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
353 h->type = STT_OBJECT;
356 && ! bfd_elf32_link_record_dynamic_symbol (info, h))
359 /* The first three global offset table entries are reserved. */
360 s->_raw_size += 3 * 4;
365 /* Look through the relocs for a section during the first phase, and
366 allocate space in the global offset table or procedure linkage
370 elf_i386_check_relocs (abfd, info, sec, relocs)
372 struct bfd_link_info *info;
374 const Elf_Internal_Rela *relocs;
377 Elf_Internal_Shdr *symtab_hdr;
378 struct elf_link_hash_entry **sym_hashes;
379 bfd_vma *local_got_offsets;
380 const Elf_Internal_Rela *rel;
381 const Elf_Internal_Rela *rel_end;
386 if (info->relocateable)
389 dynobj = elf_hash_table (info)->dynobj;
390 symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
391 sym_hashes = elf_sym_hashes (abfd);
392 local_got_offsets = elf_local_got_offsets (abfd);
398 rel_end = relocs + sec->reloc_count;
399 for (rel = relocs; rel < rel_end; rel++)
402 struct elf_link_hash_entry *h;
404 r_symndx = ELF32_R_SYM (rel->r_info);
406 if (r_symndx < symtab_hdr->sh_info)
409 h = sym_hashes[r_symndx - symtab_hdr->sh_info];
411 /* Some relocs require a global offset table. */
414 switch (ELF32_R_TYPE (rel->r_info))
419 elf_hash_table (info)->dynobj = dynobj = abfd;
420 if (! elf_i386_create_got_section (dynobj, info))
429 switch (ELF32_R_TYPE (rel->r_info))
432 /* This symbol requires a global offset table entry. */
436 sgot = bfd_get_section_by_name (dynobj, ".got");
437 BFD_ASSERT (sgot != NULL);
441 && (h != NULL || info->shared))
443 srelgot = bfd_get_section_by_name (dynobj, ".rel.got");
446 srelgot = bfd_make_section (dynobj, ".rel.got");
448 || ! bfd_set_section_flags (dynobj, srelgot,
454 || ! bfd_set_section_alignment (dynobj, srelgot, 2))
461 if (h->got_offset != (bfd_vma) -1)
463 /* We have already allocated space in the .got. */
466 h->got_offset = sgot->_raw_size;
468 /* Make sure this symbol is output as a dynamic symbol. */
469 if (h->dynindx == -1)
471 if (! bfd_elf32_link_record_dynamic_symbol (info, h))
475 srelgot->_raw_size += sizeof (Elf32_External_Rel);
479 /* This is a global offset table entry for a local
481 if (local_got_offsets == NULL)
486 size = symtab_hdr->sh_info * sizeof (bfd_vma);
487 local_got_offsets = (bfd_vma *) bfd_alloc (abfd, size);
488 if (local_got_offsets == NULL)
490 bfd_set_error (bfd_error_no_memory);
493 elf_local_got_offsets (abfd) = local_got_offsets;
494 for (i = 0; i < symtab_hdr->sh_info; i++)
495 local_got_offsets[i] = (bfd_vma) -1;
497 if (local_got_offsets[r_symndx] != (bfd_vma) -1)
499 /* We have already allocated space in the .got. */
502 local_got_offsets[r_symndx] = sgot->_raw_size;
506 /* If we are generating a shared object, we need to
507 output a R_386_RELATIVE reloc so that the dynamic
508 linker can adjust this GOT entry. */
509 srelgot->_raw_size += sizeof (Elf32_External_Rel);
513 sgot->_raw_size += 4;
518 /* This symbol requires a procedure linkage table entry. We
519 actually build the entry in adjust_dynamic_symbol,
520 because this might be a case of linking PIC code without
521 linking in any dynamic objects, in which case we don't
522 need to generate a procedure linkage table after all. */
524 /* If this is a local symbol, we resolve it directly without
525 creating a procedure linkage table entry. */
529 /* Make sure this symbol is output as a dynamic symbol. */
530 if (h->dynindx == -1)
532 if (! bfd_elf32_link_record_dynamic_symbol (info, h))
536 h->elf_link_hash_flags |= ELF_LINK_HASH_NEEDS_PLT;
543 && (sec->flags & SEC_ALLOC) != 0)
545 /* When creating a shared object, we must copy these
546 reloc types into the output file. We create a reloc
547 section in dynobj and make room for this reloc. */
552 name = (elf_string_from_elf_section
554 elf_elfheader (abfd)->e_shstrndx,
555 elf_section_data (sec)->rel_hdr.sh_name));
559 BFD_ASSERT (strncmp (name, ".rel", 4) == 0
560 && strcmp (bfd_get_section_name (abfd, sec),
563 sreloc = bfd_get_section_by_name (dynobj, name);
566 sreloc = bfd_make_section (dynobj, name);
568 || ! bfd_set_section_flags (dynobj, sreloc,
574 || ! bfd_set_section_alignment (dynobj, sreloc, 2))
579 sreloc->_raw_size += sizeof (Elf32_External_Rel);
592 /* Adjust a symbol defined by a dynamic object and referenced by a
593 regular object. The current definition is in some section of the
594 dynamic object, but we're not including those sections. We have to
595 change the definition to something the rest of the link can
599 elf_i386_adjust_dynamic_symbol (info, h)
600 struct bfd_link_info *info;
601 struct elf_link_hash_entry *h;
605 unsigned int power_of_two;
607 dynobj = elf_hash_table (info)->dynobj;
609 /* Make sure we know what is going on here. */
610 BFD_ASSERT (dynobj != NULL);
611 BFD_ASSERT ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT)
612 || ((h->elf_link_hash_flags
613 & ELF_LINK_HASH_DEF_DYNAMIC) != 0
614 && (h->elf_link_hash_flags
615 & ELF_LINK_HASH_REF_REGULAR) != 0
616 && (h->elf_link_hash_flags
617 & ELF_LINK_HASH_DEF_REGULAR) == 0
618 && (h->root.type == bfd_link_hash_defined
619 || h->root.type == bfd_link_hash_defweak)
620 && (h->root.u.def.section->owner == NULL
621 || ((elf_elfheader (h->root.u.def.section->owner)->e_type
623 && (bfd_get_flavour (h->root.u.def.section->owner)
624 == bfd_target_elf_flavour)
625 && h->root.u.def.section->output_section == NULL))));
627 /* If this is a function, put it in the procedure linkage table. We
628 will fill in the contents of the procedure linkage table later,
629 when we know the address of the .got section. */
630 if (h->type == STT_FUNC
631 || (h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) != 0)
633 if (! elf_hash_table (info)->dynamic_sections_created)
635 /* This case can occur if we saw a PLT32 reloc in an input
636 file, but none of the input files were dynamic objects.
637 In such a case, we don't actually need to build a
638 procedure linkage table, and we can just do a PC32 reloc
640 BFD_ASSERT ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) != 0);
644 s = bfd_get_section_by_name (dynobj, ".plt");
645 BFD_ASSERT (s != NULL);
647 /* If this is the first .plt entry, make room for the special
649 if (s->_raw_size == 0)
650 s->_raw_size += PLT_ENTRY_SIZE;
652 /* If this symbol is not defined in a regular file, and we are
653 not generating a shared library, then set the symbol to this
654 location in the .plt. This is required to make function
655 pointers compare as equal between the normal executable and
656 the shared library. */
658 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
660 h->root.u.def.section = s;
661 h->root.u.def.value = s->_raw_size;
664 h->plt_offset = s->_raw_size;
666 /* Make room for this entry. */
667 s->_raw_size += PLT_ENTRY_SIZE;
669 /* We also need to make an entry in the .got.plt section, which
670 will be placed in the .got section by the linker script. */
672 s = bfd_get_section_by_name (dynobj, ".got.plt");
673 BFD_ASSERT (s != NULL);
676 /* We also need to make an entry in the .rel.plt section. */
678 s = bfd_get_section_by_name (dynobj, ".rel.plt");
679 BFD_ASSERT (s != NULL);
680 s->_raw_size += sizeof (Elf32_External_Rel);
685 /* If this is a weak symbol, and there is a real definition, the
686 processor independent code will have arranged for us to see the
687 real definition first, and we can just use the same value. */
688 if (h->weakdef != NULL)
690 BFD_ASSERT (h->weakdef->root.type == bfd_link_hash_defined
691 || h->weakdef->root.type == bfd_link_hash_defweak);
692 h->root.u.def.section = h->weakdef->root.u.def.section;
693 h->root.u.def.value = h->weakdef->root.u.def.value;
697 /* This is a reference to a symbol defined by a dynamic object which
698 is not a function. */
700 /* If we are creating a shared library, we must presume that the
701 only references to the symbol are via the global offset table.
702 For such cases we need not do anything here; the relocations will
703 be handled correctly by relocate_section. */
707 /* We must allocate the symbol in our .dynbss section, which will
708 become part of the .bss section of the executable. There will be
709 an entry for this symbol in the .dynsym section. The dynamic
710 object will contain position independent code, so all references
711 from the dynamic object to this symbol will go through the global
712 offset table. The dynamic linker will use the .dynsym entry to
713 determine the address it must put in the global offset table, so
714 both the dynamic object and the regular object will refer to the
715 same memory location for the variable. */
717 s = bfd_get_section_by_name (dynobj, ".dynbss");
718 BFD_ASSERT (s != NULL);
720 /* If the symbol is currently defined in the .bss section of the
721 dynamic object, then it is OK to simply initialize it to zero.
722 If the symbol is in some other section, we must generate a
723 R_386_COPY reloc to tell the dynamic linker to copy the initial
724 value out of the dynamic object and into the runtime process
725 image. We need to remember the offset into the .rel.bss section
726 we are going to use. */
727 if ((h->root.u.def.section->flags & SEC_LOAD) != 0)
731 srel = bfd_get_section_by_name (dynobj, ".rel.bss");
732 BFD_ASSERT (srel != NULL);
733 srel->_raw_size += sizeof (Elf32_External_Rel);
734 h->elf_link_hash_flags |= ELF_LINK_HASH_NEEDS_COPY;
737 /* We need to figure out the alignment required for this symbol. I
738 have no idea how ELF linkers handle this. */
739 power_of_two = bfd_log2 (h->size);
740 if (power_of_two > 3)
743 /* Apply the required alignment. */
744 s->_raw_size = BFD_ALIGN (s->_raw_size,
745 (bfd_size_type) (1 << power_of_two));
746 if (power_of_two > bfd_get_section_alignment (dynobj, s))
748 if (! bfd_set_section_alignment (dynobj, s, power_of_two))
752 /* Define the symbol as being at this point in the section. */
753 h->root.u.def.section = s;
754 h->root.u.def.value = s->_raw_size;
756 /* Increment the section size to make room for the symbol. */
757 s->_raw_size += h->size;
762 /* Set the sizes of the dynamic sections. */
765 elf_i386_size_dynamic_sections (output_bfd, info)
767 struct bfd_link_info *info;
775 dynobj = elf_hash_table (info)->dynobj;
776 BFD_ASSERT (dynobj != NULL);
778 if (elf_hash_table (info)->dynamic_sections_created)
780 /* Set the contents of the .interp section to the interpreter. */
783 s = bfd_get_section_by_name (dynobj, ".interp");
784 BFD_ASSERT (s != NULL);
785 s->_raw_size = sizeof ELF_DYNAMIC_INTERPRETER;
786 s->contents = (unsigned char *) ELF_DYNAMIC_INTERPRETER;
791 /* We may have created entries in the .rel.got section.
792 However, if we are not creating the dynamic sections, we will
793 not actually use these entries. Reset the size of .rel.got,
794 which will cause it to get stripped from the output file
796 s = bfd_get_section_by_name (dynobj, ".rel.got");
801 /* The check_relocs and adjust_dynamic_symbol entry points have
802 determined the sizes of the various dynamic sections. Allocate
807 for (s = dynobj->sections; s != NULL; s = s->next)
812 if ((s->flags & SEC_IN_MEMORY) == 0)
815 /* It's OK to base decisions on the section name, because none
816 of the dynobj section names depend upon the input files. */
817 name = bfd_get_section_name (dynobj, s);
821 if (strcmp (name, ".plt") == 0)
823 if (s->_raw_size == 0)
825 /* Strip this section if we don't need it; see the
831 /* Remember whether there is a PLT. */
835 else if (strncmp (name, ".rel", 4) == 0)
837 if (s->_raw_size == 0)
839 /* If we don't need this section, strip it from the
840 output file. This is mostly to handle .rel.bss and
841 .rel.plt. We must create both sections in
842 create_dynamic_sections, because they must be created
843 before the linker maps input sections to output
844 sections. The linker does that before
845 adjust_dynamic_symbol is called, and it is that
846 function which decides whether anything needs to go
847 into these sections. */
854 /* Remember whether there are any reloc sections other
856 if (strcmp (name, ".rel.plt") != 0)
859 /* If this relocation section applies to a read only
860 section, then we probably need a DT_TEXTREL entry. */
861 target = bfd_get_section_by_name (output_bfd, name + 4);
863 && (target->flags & SEC_READONLY) != 0)
866 /* We use the reloc_count field as a counter if we need
867 to copy relocs into the output file. */
871 else if (strncmp (name, ".got", 4) != 0)
873 /* It's not one of our sections, so don't allocate space. */
881 for (spp = &s->output_section->owner->sections;
882 *spp != s->output_section;
885 *spp = s->output_section->next;
886 --s->output_section->owner->section_count;
891 /* Allocate memory for the section contents. */
892 s->contents = (bfd_byte *) bfd_alloc (dynobj, s->_raw_size);
893 if (s->contents == NULL && s->_raw_size != 0)
895 bfd_set_error (bfd_error_no_memory);
900 if (elf_hash_table (info)->dynamic_sections_created)
902 /* Add some entries to the .dynamic section. We fill in the
903 values later, in elf_i386_finish_dynamic_sections, but we
904 must add the entries now so that we get the correct size for
905 the .dynamic section. The DT_DEBUG entry is filled in by the
906 dynamic linker and used by the debugger. */
909 if (! bfd_elf32_add_dynamic_entry (info, DT_DEBUG, 0))
915 if (! bfd_elf32_add_dynamic_entry (info, DT_PLTGOT, 0)
916 || ! bfd_elf32_add_dynamic_entry (info, DT_PLTRELSZ, 0)
917 || ! bfd_elf32_add_dynamic_entry (info, DT_PLTREL, DT_REL)
918 || ! bfd_elf32_add_dynamic_entry (info, DT_JMPREL, 0))
924 if (! bfd_elf32_add_dynamic_entry (info, DT_REL, 0)
925 || ! bfd_elf32_add_dynamic_entry (info, DT_RELSZ, 0)
926 || ! bfd_elf32_add_dynamic_entry (info, DT_RELENT,
927 sizeof (Elf32_External_Rel)))
933 if (! bfd_elf32_add_dynamic_entry (info, DT_TEXTREL, 0))
941 /* Relocate an i386 ELF section. */
944 elf_i386_relocate_section (output_bfd, info, input_bfd, input_section,
945 contents, relocs, local_syms, local_sections)
947 struct bfd_link_info *info;
949 asection *input_section;
951 Elf_Internal_Rela *relocs;
952 Elf_Internal_Sym *local_syms;
953 asection **local_sections;
956 Elf_Internal_Shdr *symtab_hdr;
957 struct elf_link_hash_entry **sym_hashes;
958 bfd_vma *local_got_offsets;
962 Elf_Internal_Rela *rel;
963 Elf_Internal_Rela *relend;
965 dynobj = elf_hash_table (info)->dynobj;
966 symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr;
967 sym_hashes = elf_sym_hashes (input_bfd);
968 local_got_offsets = elf_local_got_offsets (input_bfd);
975 relend = relocs + input_section->reloc_count;
976 for (; rel < relend; rel++)
979 reloc_howto_type *howto;
981 struct elf_link_hash_entry *h;
982 Elf_Internal_Sym *sym;
985 bfd_reloc_status_type r;
988 r_type = ELF32_R_TYPE (rel->r_info);
989 if (r_type < 0 || r_type >= (int) R_386_max)
991 bfd_set_error (bfd_error_bad_value);
994 howto = elf_howto_table + r_type;
996 r_symndx = ELF32_R_SYM (rel->r_info);
998 if (info->relocateable)
1000 /* This is a relocateable link. We don't have to change
1001 anything, unless the reloc is against a section symbol,
1002 in which case we have to adjust according to where the
1003 section symbol winds up in the output section. */
1004 if (r_symndx < symtab_hdr->sh_info)
1006 sym = local_syms + r_symndx;
1007 if (ELF_ST_TYPE (sym->st_info) == STT_SECTION)
1011 sec = local_sections[r_symndx];
1012 val = bfd_get_32 (input_bfd, contents + rel->r_offset);
1013 val += sec->output_offset + sym->st_value;
1014 bfd_put_32 (input_bfd, val, contents + rel->r_offset);
1021 /* This is a final link. */
1027 if (r_symndx < symtab_hdr->sh_info)
1029 sym = local_syms + r_symndx;
1030 sec = local_sections[r_symndx];
1031 relocation = (sec->output_section->vma
1032 + sec->output_offset
1037 h = sym_hashes[r_symndx - symtab_hdr->sh_info];
1038 if (h->root.type == bfd_link_hash_defined
1039 || h->root.type == bfd_link_hash_defweak)
1041 sec = h->root.u.def.section;
1042 if (r_type == R_386_GOTPC
1043 || (r_type == R_386_PLT32
1044 && h->plt_offset != (bfd_vma) -1)
1045 || (r_type == R_386_GOT32
1046 && elf_hash_table (info)->dynamic_sections_created)
1048 && (r_type == R_386_32
1049 || r_type == R_386_PC32)
1050 && (input_section->flags & SEC_ALLOC) != 0))
1052 /* In these cases, we don't need the relocation
1053 value. We check specially because in some
1054 obscure cases sec->output_section will be NULL. */
1058 relocation = (h->root.u.def.value
1059 + sec->output_section->vma
1060 + sec->output_offset);
1062 else if (h->root.type == bfd_link_hash_undefweak)
1064 else if (info->shared)
1068 if (! ((*info->callbacks->undefined_symbol)
1069 (info, h->root.root.string, input_bfd,
1070 input_section, rel->r_offset)))
1079 /* Relocation is to the entry for this symbol in the global
1083 sgot = bfd_get_section_by_name (dynobj, ".got");
1084 BFD_ASSERT (sgot != NULL);
1091 off = h->got_offset;
1092 BFD_ASSERT (off != (bfd_vma) -1);
1094 if (! elf_hash_table (info)->dynamic_sections_created)
1096 /* This is actually a static link. We must
1097 initialize this entry in the global offset table.
1098 Since the offset must always be a multiple of 4,
1099 we use the least significant bit to record
1100 whether we have initialized it already.
1102 When doing a dynamic link, we create a .rel.got
1103 relocation entry to initialize the value. This
1104 is done in the finish_dynamic_symbol routine. */
1109 bfd_put_32 (output_bfd, relocation,
1110 sgot->contents + off);
1115 relocation = sgot->output_offset + off;
1121 BFD_ASSERT (local_got_offsets != NULL
1122 && local_got_offsets[r_symndx] != (bfd_vma) -1);
1124 off = local_got_offsets[r_symndx];
1126 /* The offset must always be a multiple of 4. We use
1127 the least significant bit to record whether we have
1128 already generated the necessary reloc. */
1133 bfd_put_32 (output_bfd, relocation, sgot->contents + off);
1138 Elf_Internal_Rel outrel;
1140 srelgot = bfd_get_section_by_name (dynobj, ".rel.got");
1141 BFD_ASSERT (srelgot != NULL);
1143 outrel.r_offset = (sgot->output_section->vma
1144 + sgot->output_offset
1146 outrel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
1147 bfd_elf32_swap_reloc_out (output_bfd, &outrel,
1148 (((Elf32_External_Rel *)
1150 + srelgot->reloc_count));
1151 ++srelgot->reloc_count;
1154 local_got_offsets[r_symndx] |= 1;
1157 relocation = sgot->output_offset + off;
1163 /* Relocation is relative to the start of the global offset
1168 sgot = bfd_get_section_by_name (dynobj, ".got");
1169 BFD_ASSERT (sgot != NULL);
1172 /* Note that sgot->output_offset is not involved in this
1173 calculation. We always want the start of .got. If we
1174 defined _GLOBAL_OFFSET_TABLE in a different way, as is
1175 permitted by the ABI, we might have to change this
1177 relocation -= sgot->output_section->vma;
1182 /* Use global offset table as symbol value. */
1186 sgot = bfd_get_section_by_name (dynobj, ".got");
1187 BFD_ASSERT (sgot != NULL);
1190 relocation = sgot->output_section->vma;
1195 /* Relocation is to the entry for this symbol in the
1196 procedure linkage table. */
1198 /* Resolve a PLT32 reloc again a local symbol directly,
1199 without using the procedure linkage table. */
1203 if (h->plt_offset == (bfd_vma) -1)
1205 /* We didn't make a PLT entry for this symbol. This
1206 happens when statically linking PIC code. */
1212 splt = bfd_get_section_by_name (dynobj, ".plt");
1213 BFD_ASSERT (splt != NULL);
1216 relocation = (splt->output_section->vma
1217 + splt->output_offset
1225 && (input_section->flags & SEC_ALLOC) != 0)
1227 Elf_Internal_Rel outrel;
1229 /* When generating a shared object, these relocations
1230 are copied into the output file to be resolved at run
1235 shared_name = (elf_string_from_elf_section
1237 elf_elfheader (input_bfd)->e_shstrndx,
1238 elf_section_data (input_section)->rel_hdr.sh_name));
1239 if (shared_name == NULL)
1242 BFD_ASSERT (strncmp (shared_name, ".rel", 4) == 0
1243 && strcmp (bfd_get_section_name (input_bfd,
1245 shared_name + 4) == 0);
1247 sreloc = bfd_get_section_by_name (dynobj, shared_name);
1248 BFD_ASSERT (sreloc != NULL);
1251 outrel.r_offset = (rel->r_offset
1252 + input_section->output_section->vma
1253 + input_section->output_offset);
1254 if (r_type == R_386_PC32)
1258 if (! ((*info->callbacks->undefined_symbol)
1259 (info, shared_name ? shared_name : sec->name, input_bfd,
1260 input_section, rel->r_offset)))
1261 bfd_set_error (bfd_error_bad_value);
1265 BFD_ASSERT (h->dynindx != -1);
1266 outrel.r_info = ELF32_R_INFO (h->dynindx, R_386_PC32);
1272 outrel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
1275 BFD_ASSERT (h->dynindx != (bfd_vma) -1);
1276 outrel.r_info = ELF32_R_INFO (h->dynindx, R_386_32);
1280 bfd_elf32_swap_reloc_out (output_bfd, &outrel,
1281 (((Elf32_External_Rel *)
1283 + sreloc->reloc_count));
1284 ++sreloc->reloc_count;
1286 /* If this reloc is against an external symbol, we do
1287 not want to fiddle with the addend. Otherwise, we
1288 need to include the symbol value so that it becomes
1289 an addend for the dynamic reloc. */
1300 r = _bfd_final_link_relocate (howto, input_bfd, input_section,
1301 contents, rel->r_offset,
1302 relocation, (bfd_vma) 0);
1304 if (r != bfd_reloc_ok)
1309 case bfd_reloc_outofrange:
1311 case bfd_reloc_overflow:
1316 name = h->root.root.string;
1319 name = elf_string_from_elf_section (input_bfd,
1320 symtab_hdr->sh_link,
1325 name = bfd_section_name (input_bfd, sec);
1327 if (! ((*info->callbacks->reloc_overflow)
1328 (info, name, howto->name, (bfd_vma) 0,
1329 input_bfd, input_section, rel->r_offset)))
1340 /* Finish up dynamic symbol handling. We set the contents of various
1341 dynamic sections here. */
1344 elf_i386_finish_dynamic_symbol (output_bfd, info, h, sym)
1346 struct bfd_link_info *info;
1347 struct elf_link_hash_entry *h;
1348 Elf_Internal_Sym *sym;
1352 dynobj = elf_hash_table (info)->dynobj;
1354 if (h->plt_offset != (bfd_vma) -1)
1361 Elf_Internal_Rel rel;
1363 /* This symbol has an entry in the procedure linkage table. Set
1366 BFD_ASSERT (h->dynindx != -1);
1368 splt = bfd_get_section_by_name (dynobj, ".plt");
1369 sgot = bfd_get_section_by_name (dynobj, ".got.plt");
1370 srel = bfd_get_section_by_name (dynobj, ".rel.plt");
1371 BFD_ASSERT (splt != NULL && sgot != NULL && srel != NULL);
1373 /* Get the index in the procedure linkage table which
1374 corresponds to this symbol. This is the index of this symbol
1375 in all the symbols for which we are making plt entries. The
1376 first entry in the procedure linkage table is reserved. */
1377 plt_index = h->plt_offset / PLT_ENTRY_SIZE - 1;
1379 /* Get the offset into the .got table of the entry that
1380 corresponds to this function. Each .got entry is 4 bytes.
1381 The first three are reserved. */
1382 got_offset = (plt_index + 3) * 4;
1384 /* Fill in the entry in the procedure linkage table. */
1387 memcpy (splt->contents + h->plt_offset, elf_i386_plt_entry,
1389 bfd_put_32 (output_bfd,
1390 (sgot->output_section->vma
1391 + sgot->output_offset
1393 splt->contents + h->plt_offset + 2);
1397 memcpy (splt->contents + h->plt_offset, elf_i386_pic_plt_entry,
1399 bfd_put_32 (output_bfd, got_offset,
1400 splt->contents + h->plt_offset + 2);
1403 bfd_put_32 (output_bfd, plt_index * sizeof (Elf32_External_Rel),
1404 splt->contents + h->plt_offset + 7);
1405 bfd_put_32 (output_bfd, - (h->plt_offset + PLT_ENTRY_SIZE),
1406 splt->contents + h->plt_offset + 12);
1408 /* Fill in the entry in the global offset table. */
1409 bfd_put_32 (output_bfd,
1410 (splt->output_section->vma
1411 + splt->output_offset
1414 sgot->contents + got_offset);
1416 /* Fill in the entry in the .rel.plt section. */
1417 rel.r_offset = (sgot->output_section->vma
1418 + sgot->output_offset
1420 rel.r_info = ELF32_R_INFO (h->dynindx, R_386_JUMP_SLOT);
1421 bfd_elf32_swap_reloc_out (output_bfd, &rel,
1422 ((Elf32_External_Rel *) srel->contents
1425 if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
1427 /* Mark the symbol as undefined, rather than as defined in
1428 the .plt section. Leave the value alone. */
1429 sym->st_shndx = SHN_UNDEF;
1433 if (h->got_offset != (bfd_vma) -1)
1437 Elf_Internal_Rel rel;
1439 /* This symbol has an entry in the global offset table. Set it
1442 BFD_ASSERT (h->dynindx != -1);
1444 sgot = bfd_get_section_by_name (dynobj, ".got");
1445 srel = bfd_get_section_by_name (dynobj, ".rel.got");
1446 BFD_ASSERT (sgot != NULL && srel != NULL);
1448 bfd_put_32 (output_bfd, (bfd_vma) 0, sgot->contents + h->got_offset);
1450 rel.r_offset = (sgot->output_section->vma
1451 + sgot->output_offset
1453 rel.r_info = ELF32_R_INFO (h->dynindx, R_386_GLOB_DAT);
1454 bfd_elf32_swap_reloc_out (output_bfd, &rel,
1455 ((Elf32_External_Rel *) srel->contents
1456 + srel->reloc_count));
1457 ++srel->reloc_count;
1460 if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_COPY) != 0)
1463 Elf_Internal_Rel rel;
1465 /* This symbol needs a copy reloc. Set it up. */
1467 BFD_ASSERT (h->dynindx != -1
1468 && (h->root.type == bfd_link_hash_defined
1469 || h->root.type == bfd_link_hash_defweak));
1471 s = bfd_get_section_by_name (h->root.u.def.section->owner,
1473 BFD_ASSERT (s != NULL);
1475 rel.r_offset = (h->root.u.def.value
1476 + h->root.u.def.section->output_section->vma
1477 + h->root.u.def.section->output_offset);
1478 rel.r_info = ELF32_R_INFO (h->dynindx, R_386_COPY);
1479 bfd_elf32_swap_reloc_out (output_bfd, &rel,
1480 ((Elf32_External_Rel *) s->contents
1485 /* Mark _DYNAMIC and _GLOBAL_OFFSET_TABLE_ as absolute. */
1486 if (strcmp (h->root.root.string, "_DYNAMIC") == 0
1487 || strcmp (h->root.root.string, "_GLOBAL_OFFSET_TABLE_") == 0)
1488 sym->st_shndx = SHN_ABS;
1493 /* Finish up the dynamic sections. */
1496 elf_i386_finish_dynamic_sections (output_bfd, info)
1498 struct bfd_link_info *info;
1504 dynobj = elf_hash_table (info)->dynobj;
1506 sgot = bfd_get_section_by_name (dynobj, ".got.plt");
1507 BFD_ASSERT (sgot != NULL);
1508 sdyn = bfd_get_section_by_name (dynobj, ".dynamic");
1510 if (elf_hash_table (info)->dynamic_sections_created)
1513 Elf32_External_Dyn *dyncon, *dynconend;
1515 splt = bfd_get_section_by_name (dynobj, ".plt");
1516 BFD_ASSERT (splt != NULL && sdyn != NULL);
1518 dyncon = (Elf32_External_Dyn *) sdyn->contents;
1519 dynconend = (Elf32_External_Dyn *) (sdyn->contents + sdyn->_raw_size);
1520 for (; dyncon < dynconend; dyncon++)
1522 Elf_Internal_Dyn dyn;
1526 bfd_elf32_swap_dyn_in (dynobj, dyncon, &dyn);
1539 s = bfd_get_section_by_name (output_bfd, name);
1540 BFD_ASSERT (s != NULL);
1541 dyn.d_un.d_ptr = s->vma;
1542 bfd_elf32_swap_dyn_out (output_bfd, &dyn, dyncon);
1546 s = bfd_get_section_by_name (output_bfd, ".rel.plt");
1547 BFD_ASSERT (s != NULL);
1548 if (s->_cooked_size != 0)
1549 dyn.d_un.d_val = s->_cooked_size;
1551 dyn.d_un.d_val = s->_raw_size;
1552 bfd_elf32_swap_dyn_out (output_bfd, &dyn, dyncon);
1556 /* My reading of the SVR4 ABI indicates that the
1557 procedure linkage table relocs (DT_JMPREL) should be
1558 included in the overall relocs (DT_REL). This is
1559 what Solaris does. However, UnixWare can not handle
1560 that case. Therefore, we override the DT_RELSZ entry
1561 here to make it not include the JMPREL relocs. Since
1562 the linker script arranges for .rel.plt to follow all
1563 other relocation sections, we don't have to worry
1564 about changing the DT_REL entry. */
1565 s = bfd_get_section_by_name (output_bfd, ".rel.plt");
1568 if (s->_cooked_size != 0)
1569 dyn.d_un.d_val -= s->_cooked_size;
1571 dyn.d_un.d_val -= s->_raw_size;
1573 bfd_elf32_swap_dyn_out (output_bfd, &dyn, dyncon);
1578 /* Fill in the first entry in the procedure linkage table. */
1579 if (splt->_raw_size > 0)
1582 memcpy (splt->contents, elf_i386_pic_plt0_entry, PLT_ENTRY_SIZE);
1585 memcpy (splt->contents, elf_i386_plt0_entry, PLT_ENTRY_SIZE);
1586 bfd_put_32 (output_bfd,
1587 sgot->output_section->vma + sgot->output_offset + 4,
1588 splt->contents + 2);
1589 bfd_put_32 (output_bfd,
1590 sgot->output_section->vma + sgot->output_offset + 8,
1591 splt->contents + 8);
1595 /* UnixWare sets the entsize of .plt to 4, although that doesn't
1596 really seem like the right value. */
1597 elf_section_data (splt->output_section)->this_hdr.sh_entsize = 4;
1600 /* Fill in the first three entries in the global offset table. */
1601 if (sgot->_raw_size > 0)
1604 bfd_put_32 (output_bfd, (bfd_vma) 0, sgot->contents);
1606 bfd_put_32 (output_bfd,
1607 sdyn->output_section->vma + sdyn->output_offset,
1609 bfd_put_32 (output_bfd, (bfd_vma) 0, sgot->contents + 4);
1610 bfd_put_32 (output_bfd, (bfd_vma) 0, sgot->contents + 8);
1613 elf_section_data (sgot->output_section)->this_hdr.sh_entsize = 4;
1618 #define TARGET_LITTLE_SYM bfd_elf32_i386_vec
1619 #define TARGET_LITTLE_NAME "elf32-i386"
1620 #define ELF_ARCH bfd_arch_i386
1621 #define ELF_MACHINE_CODE EM_386
1622 #define elf_info_to_howto elf_i386_info_to_howto
1623 #define elf_info_to_howto_rel elf_i386_info_to_howto_rel
1624 #define bfd_elf32_bfd_reloc_type_lookup elf_i386_reloc_type_lookup
1625 #define ELF_MAXPAGESIZE 0x1000
1626 #define elf_backend_create_dynamic_sections \
1627 elf_i386_create_dynamic_sections
1628 #define elf_backend_check_relocs elf_i386_check_relocs
1629 #define elf_backend_adjust_dynamic_symbol \
1630 elf_i386_adjust_dynamic_symbol
1631 #define elf_backend_size_dynamic_sections \
1632 elf_i386_size_dynamic_sections
1633 #define elf_backend_relocate_section elf_i386_relocate_section
1634 #define elf_backend_finish_dynamic_symbol \
1635 elf_i386_finish_dynamic_symbol
1636 #define elf_backend_finish_dynamic_sections \
1637 elf_i386_finish_dynamic_sections
1639 #include "elf32-target.h"