/* ELF linking support for BFD. Copyright 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc. This file is part of BFD, the Binary File Descriptor library. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include "bfd.h" #include "sysdep.h" #include "bfdlink.h" #include "libbfd.h" #define ARCH_SIZE 0 #include "elf-bfd.h" bfd_boolean _bfd_elf_create_got_section (bfd *abfd, struct bfd_link_info *info) { flagword flags; asection *s; struct elf_link_hash_entry *h; struct bfd_link_hash_entry *bh; const struct elf_backend_data *bed = get_elf_backend_data (abfd); int ptralign; /* This function may be called more than once. */ s = bfd_get_section_by_name (abfd, ".got"); if (s != NULL && (s->flags & SEC_LINKER_CREATED) != 0) return TRUE; switch (bed->s->arch_size) { case 32: ptralign = 2; break; case 64: ptralign = 3; break; default: bfd_set_error (bfd_error_bad_value); return FALSE; } flags = (SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY | SEC_LINKER_CREATED); s = bfd_make_section (abfd, ".got"); if (s == NULL || !bfd_set_section_flags (abfd, s, flags) || !bfd_set_section_alignment (abfd, s, ptralign)) return FALSE; if (bed->want_got_plt) { s = bfd_make_section (abfd, ".got.plt"); if (s == NULL || !bfd_set_section_flags (abfd, s, flags) || !bfd_set_section_alignment (abfd, s, ptralign)) return FALSE; } if (bed->want_got_sym) { /* Define the symbol _GLOBAL_OFFSET_TABLE_ at the start of the .got (or .got.plt) section. We don't do this in the linker script because we don't want to define the symbol if we are not creating a global offset table. */ bh = NULL; if (!(_bfd_generic_link_add_one_symbol (info, abfd, "_GLOBAL_OFFSET_TABLE_", BSF_GLOBAL, s, bed->got_symbol_offset, NULL, FALSE, bed->collect, &bh))) return FALSE; h = (struct elf_link_hash_entry *) bh; h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR; h->type = STT_OBJECT; if (! info->executable && ! _bfd_elf_link_record_dynamic_symbol (info, h)) return FALSE; elf_hash_table (info)->hgot = h; } /* The first bit of the global offset table is the header. */ s->_raw_size += bed->got_header_size + bed->got_symbol_offset; return TRUE; } /* Create some sections which will be filled in with dynamic linking information. ABFD is an input file which requires dynamic sections to be created. The dynamic sections take up virtual memory space when the final executable is run, so we need to create them before addresses are assigned to the output sections. We work out the actual contents and size of these sections later. */ bfd_boolean _bfd_elf_link_create_dynamic_sections (bfd *abfd, struct bfd_link_info *info) { flagword flags; register asection *s; struct elf_link_hash_entry *h; struct bfd_link_hash_entry *bh; const struct elf_backend_data *bed; if (! is_elf_hash_table (info->hash)) return FALSE; if (elf_hash_table (info)->dynamic_sections_created) return TRUE; /* Make sure that all dynamic sections use the same input BFD. */ if (elf_hash_table (info)->dynobj == NULL) elf_hash_table (info)->dynobj = abfd; else abfd = elf_hash_table (info)->dynobj; /* Note that we set the SEC_IN_MEMORY flag for all of these sections. */ flags = (SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY | SEC_LINKER_CREATED); /* A dynamically linked executable has a .interp section, but a shared library does not. */ if (info->executable) { s = bfd_make_section (abfd, ".interp"); if (s == NULL || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)) return FALSE; } if (! info->traditional_format) { s = bfd_make_section (abfd, ".eh_frame_hdr"); if (s == NULL || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY) || ! bfd_set_section_alignment (abfd, s, 2)) return FALSE; elf_hash_table (info)->eh_info.hdr_sec = s; } bed = get_elf_backend_data (abfd); /* Create sections to hold version informations. These are removed if they are not needed. */ s = bfd_make_section (abfd, ".gnu.version_d"); if (s == NULL || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY) || ! bfd_set_section_alignment (abfd, s, bed->s->log_file_align)) return FALSE; s = bfd_make_section (abfd, ".gnu.version"); if (s == NULL || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY) || ! bfd_set_section_alignment (abfd, s, 1)) return FALSE; s = bfd_make_section (abfd, ".gnu.version_r"); if (s == NULL || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY) || ! bfd_set_section_alignment (abfd, s, bed->s->log_file_align)) return FALSE; s = bfd_make_section (abfd, ".dynsym"); if (s == NULL || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY) || ! bfd_set_section_alignment (abfd, s, bed->s->log_file_align)) return FALSE; s = bfd_make_section (abfd, ".dynstr"); if (s == NULL || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)) return FALSE; /* Create a strtab to hold the dynamic symbol names. */ if (elf_hash_table (info)->dynstr == NULL) { elf_hash_table (info)->dynstr = _bfd_elf_strtab_init (); if (elf_hash_table (info)->dynstr == NULL) return FALSE; } s = bfd_make_section (abfd, ".dynamic"); if (s == NULL || ! bfd_set_section_flags (abfd, s, flags) || ! bfd_set_section_alignment (abfd, s, bed->s->log_file_align)) return FALSE; /* The special symbol _DYNAMIC is always set to the start of the .dynamic section. This call occurs before we have processed the symbols for any dynamic object, so we don't have to worry about overriding a dynamic definition. We could set _DYNAMIC in a linker script, but we only want to define it if we are, in fact, creating a .dynamic section. We don't want to define it if there is no .dynamic section, since on some ELF platforms the start up code examines it to decide how to initialize the process. */ bh = NULL; if (! (_bfd_generic_link_add_one_symbol (info, abfd, "_DYNAMIC", BSF_GLOBAL, s, 0, NULL, FALSE, get_elf_backend_data (abfd)->collect, &bh))) return FALSE; h = (struct elf_link_hash_entry *) bh; h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR; h->type = STT_OBJECT; if (! info->executable && ! _bfd_elf_link_record_dynamic_symbol (info, h)) return FALSE; s = bfd_make_section (abfd, ".hash"); if (s == NULL || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY) || ! bfd_set_section_alignment (abfd, s, bed->s->log_file_align)) return FALSE; elf_section_data (s)->this_hdr.sh_entsize = bed->s->sizeof_hash_entry; /* Let the backend create the rest of the sections. This lets the backend set the right flags. The backend will normally create the .got and .plt sections. */ if (! (*bed->elf_backend_create_dynamic_sections) (abfd, info)) return FALSE; elf_hash_table (info)->dynamic_sections_created = TRUE; return TRUE; } /* Create dynamic sections when linking against a dynamic object. */ bfd_boolean _bfd_elf_create_dynamic_sections (bfd *abfd, struct bfd_link_info *info) { flagword flags, pltflags; asection *s; const struct elf_backend_data *bed = get_elf_backend_data (abfd); /* We need to create .plt, .rel[a].plt, .got, .got.plt, .dynbss, and .rel[a].bss sections. */ flags = (SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY | SEC_LINKER_CREATED); pltflags = flags; pltflags |= SEC_CODE; if (bed->plt_not_loaded) pltflags &= ~ (SEC_CODE | SEC_LOAD | SEC_HAS_CONTENTS); if (bed->plt_readonly) pltflags |= SEC_READONLY; s = bfd_make_section (abfd, ".plt"); if (s == NULL || ! bfd_set_section_flags (abfd, s, pltflags) || ! bfd_set_section_alignment (abfd, s, bed->plt_alignment)) return FALSE; if (bed->want_plt_sym) { /* Define the symbol _PROCEDURE_LINKAGE_TABLE_ at the start of the .plt section. */ struct elf_link_hash_entry *h; struct bfd_link_hash_entry *bh = NULL; if (! (_bfd_generic_link_add_one_symbol (info, abfd, "_PROCEDURE_LINKAGE_TABLE_", BSF_GLOBAL, s, 0, NULL, FALSE, get_elf_backend_data (abfd)->collect, &bh))) return FALSE; h = (struct elf_link_hash_entry *) bh; h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR; h->type = STT_OBJECT; if (! info->executable && ! _bfd_elf_link_record_dynamic_symbol (info, h)) return FALSE; } s = bfd_make_section (abfd, bed->default_use_rela_p ? ".rela.plt" : ".rel.plt"); if (s == NULL || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY) || ! bfd_set_section_alignment (abfd, s, bed->s->log_file_align)) return FALSE; if (! _bfd_elf_create_got_section (abfd, info)) return FALSE; if (bed->want_dynbss) { /* The .dynbss section is a place to put symbols which are defined by dynamic objects, are referenced by regular objects, and are not functions. We must allocate space for them in the process image and use a R_*_COPY reloc to tell the dynamic linker to initialize them at run time. The linker script puts the .dynbss section into the .bss section of the final image. */ s = bfd_make_section (abfd, ".dynbss"); if (s == NULL || ! bfd_set_section_flags (abfd, s, SEC_ALLOC | SEC_LINKER_CREATED)) return FALSE; /* The .rel[a].bss section holds copy relocs. This section is not normally needed. We need to create it here, though, so that the linker will map it to an output section. We can't just create it only if we need it, because we will not know whether we need it until we have seen all the input files, and the first time the main linker code calls BFD after examining all the input files (size_dynamic_sections) the input sections have already been mapped to the output sections. If the section turns out not to be needed, we can discard it later. We will never need this section when generating a shared object, since they do not use copy relocs. */ if (! info->shared) { s = bfd_make_section (abfd, (bed->default_use_rela_p ? ".rela.bss" : ".rel.bss")); if (s == NULL || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY) || ! bfd_set_section_alignment (abfd, s, bed->s->log_file_align)) return FALSE; } } return TRUE; } /* Record a new dynamic symbol. We record the dynamic symbols as we read the input files, since we need to have a list of all of them before we can determine the final sizes of the output sections. Note that we may actually call this function even though we are not going to output any dynamic symbols; in some cases we know that a symbol should be in the dynamic symbol table, but only if there is one. */ bfd_boolean _bfd_elf_link_record_dynamic_symbol (struct bfd_link_info *info, struct elf_link_hash_entry *h) { if (h->dynindx == -1) { struct elf_strtab_hash *dynstr; char *p; const char *name; bfd_size_type indx; /* XXX: The ABI draft says the linker must turn hidden and internal symbols into STB_LOCAL symbols when producing the DSO. However, if ld.so honors st_other in the dynamic table, this would not be necessary. */ switch (ELF_ST_VISIBILITY (h->other)) { case STV_INTERNAL: case STV_HIDDEN: if (h->root.type != bfd_link_hash_undefined && h->root.type != bfd_link_hash_undefweak) { h->elf_link_hash_flags |= ELF_LINK_FORCED_LOCAL; return TRUE; } default: break; } h->dynindx = elf_hash_table (info)->dynsymcount; ++elf_hash_table (info)->dynsymcount; dynstr = elf_hash_table (info)->dynstr; if (dynstr == NULL) { /* Create a strtab to hold the dynamic symbol names. */ elf_hash_table (info)->dynstr = dynstr = _bfd_elf_strtab_init (); if (dynstr == NULL) return FALSE; } /* We don't put any version information in the dynamic string table. */ name = h->root.root.string; p = strchr (name, ELF_VER_CHR); if (p != NULL) /* We know that the p points into writable memory. In fact, there are only a few symbols that have read-only names, being those like _GLOBAL_OFFSET_TABLE_ that are created specially by the backends. Most symbols will have names pointing into an ELF string table read from a file, or to objalloc memory. */ *p = 0; indx = _bfd_elf_strtab_add (dynstr, name, p != NULL); if (p != NULL) *p = ELF_VER_CHR; if (indx == (bfd_size_type) -1) return FALSE; h->dynstr_index = indx; } return TRUE; } /* Record an assignment to a symbol made by a linker script. We need this in case some dynamic object refers to this symbol. */ bfd_boolean bfd_elf_record_link_assignment (bfd *output_bfd ATTRIBUTE_UNUSED, struct bfd_link_info *info, const char *name, bfd_boolean provide) { struct elf_link_hash_entry *h; if (!is_elf_hash_table (info->hash)) return TRUE; h = elf_link_hash_lookup (elf_hash_table (info), name, TRUE, TRUE, FALSE); if (h == NULL) return FALSE; /* Since we're defining the symbol, don't let it seem to have not been defined. record_dynamic_symbol and size_dynamic_sections may depend on this. */ if (h->root.type == bfd_link_hash_undefweak || h->root.type == bfd_link_hash_undefined) h->root.type = bfd_link_hash_new; if (h->root.type == bfd_link_hash_new) h->elf_link_hash_flags &= ~ELF_LINK_NON_ELF; /* If this symbol is being provided by the linker script, and it is currently defined by a dynamic object, but not by a regular object, then mark it as undefined so that the generic linker will force the correct value. */ if (provide && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0) h->root.type = bfd_link_hash_undefined; /* If this symbol is not being provided by the linker script, and it is currently defined by a dynamic object, but not by a regular object, then clear out any version information because the symbol will not be associated with the dynamic object any more. */ if (!provide && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0) h->verinfo.verdef = NULL; h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR; if (((h->elf_link_hash_flags & (ELF_LINK_HASH_DEF_DYNAMIC | ELF_LINK_HASH_REF_DYNAMIC)) != 0 || info->shared) && h->dynindx == -1) { if (! _bfd_elf_link_record_dynamic_symbol (info, h)) return FALSE; /* If this is a weak defined symbol, and we know a corresponding real symbol from the same dynamic object, make sure the real symbol is also made into a dynamic symbol. */ if (h->weakdef != NULL && h->weakdef->dynindx == -1) { if (! _bfd_elf_link_record_dynamic_symbol (info, h->weakdef)) return FALSE; } } return TRUE; } /* Record a new local dynamic symbol. Returns 0 on failure, 1 on success, and 2 on a failure caused by attempting to record a symbol in a discarded section, eg. a discarded link-once section symbol. */ int elf_link_record_local_dynamic_symbol (struct bfd_link_info *info, bfd *input_bfd, long input_indx) { bfd_size_type amt; struct elf_link_local_dynamic_entry *entry; struct elf_link_hash_table *eht; struct elf_strtab_hash *dynstr; unsigned long dynstr_index; char *name; Elf_External_Sym_Shndx eshndx; char esym[sizeof (Elf64_External_Sym)]; if (! is_elf_hash_table (info->hash)) return 0; /* See if the entry exists already. */ for (entry = elf_hash_table (info)->dynlocal; entry ; entry = entry->next) if (entry->input_bfd == input_bfd && entry->input_indx == input_indx) return 1; amt = sizeof (*entry); entry = bfd_alloc (input_bfd, amt); if (entry == NULL) return 0; /* Go find the symbol, so that we can find it's name. */ if (!bfd_elf_get_elf_syms (input_bfd, &elf_tdata (input_bfd)->symtab_hdr, 1, input_indx, &entry->isym, esym, &eshndx)) { bfd_release (input_bfd, entry); return 0; } if (entry->isym.st_shndx != SHN_UNDEF && (entry->isym.st_shndx < SHN_LORESERVE || entry->isym.st_shndx > SHN_HIRESERVE)) { asection *s; s = bfd_section_from_elf_index (input_bfd, entry->isym.st_shndx); if (s == NULL || bfd_is_abs_section (s->output_section)) { /* We can still bfd_release here as nothing has done another bfd_alloc. We can't do this later in this function. */ bfd_release (input_bfd, entry); return 2; } } name = (bfd_elf_string_from_elf_section (input_bfd, elf_tdata (input_bfd)->symtab_hdr.sh_link, entry->isym.st_name)); dynstr = elf_hash_table (info)->dynstr; if (dynstr == NULL) { /* Create a strtab to hold the dynamic symbol names. */ elf_hash_table (info)->dynstr = dynstr = _bfd_elf_strtab_init (); if (dynstr == NULL) return 0; } dynstr_index = _bfd_elf_strtab_add (dynstr, name, FALSE); if (dynstr_index == (unsigned long) -1) return 0; entry->isym.st_name = dynstr_index; eht = elf_hash_table (info); entry->next = eht->dynlocal; eht->dynlocal = entry; entry->input_bfd = input_bfd; entry->input_indx = input_indx; eht->dynsymcount++; /* Whatever binding the symbol had before, it's now local. */ entry->isym.st_info = ELF_ST_INFO (STB_LOCAL, ELF_ST_TYPE (entry->isym.st_info)); /* The dynindx will be set at the end of size_dynamic_sections. */ return 1; } /* Return the dynindex of a local dynamic symbol. */ long _bfd_elf_link_lookup_local_dynindx (struct bfd_link_info *info, bfd *input_bfd, long input_indx) { struct elf_link_local_dynamic_entry *e; for (e = elf_hash_table (info)->dynlocal; e ; e = e->next) if (e->input_bfd == input_bfd && e->input_indx == input_indx) return e->dynindx; return -1; } /* This function is used to renumber the dynamic symbols, if some of them are removed because they are marked as local. This is called via elf_link_hash_traverse. */ static bfd_boolean elf_link_renumber_hash_table_dynsyms (struct elf_link_hash_entry *h, void *data) { size_t *count = data; if (h->root.type == bfd_link_hash_warning) h = (struct elf_link_hash_entry *) h->root.u.i.link; if (h->dynindx != -1) h->dynindx = ++(*count); return TRUE; } /* Assign dynsym indices. In a shared library we generate a section symbol for each output section, which come first. Next come all of the back-end allocated local dynamic syms, followed by the rest of the global symbols. */ unsigned long _bfd_elf_link_renumber_dynsyms (bfd *output_bfd, struct bfd_link_info *info) { unsigned long dynsymcount = 0; if (info->shared) { asection *p; for (p = output_bfd->sections; p ; p = p->next) if ((p->flags & SEC_EXCLUDE) == 0) elf_section_data (p)->dynindx = ++dynsymcount; } if (elf_hash_table (info)->dynlocal) { struct elf_link_local_dynamic_entry *p; for (p = elf_hash_table (info)->dynlocal; p ; p = p->next) p->dynindx = ++dynsymcount; } elf_link_hash_traverse (elf_hash_table (info), elf_link_renumber_hash_table_dynsyms, &dynsymcount); /* There is an unused NULL entry at the head of the table which we must account for in our count. Unless there weren't any symbols, which means we'll have no table at all. */ if (dynsymcount != 0) ++dynsymcount; return elf_hash_table (info)->dynsymcount = dynsymcount; } /* This function is called when we want to define a new symbol. It handles the various cases which arise when we find a definition in a dynamic object, or when there is already a definition in a dynamic object. The new symbol is described by NAME, SYM, PSEC, and PVALUE. We set SYM_HASH to the hash table entry. We set OVERRIDE if the old symbol is overriding a new definition. We set TYPE_CHANGE_OK if it is OK for the type to change. We set SIZE_CHANGE_OK if it is OK for the size to change. By OK to change, we mean that we shouldn't warn if the type or size does change. */ bfd_boolean _bfd_elf_merge_symbol (bfd *abfd, struct bfd_link_info *info, const char *name, Elf_Internal_Sym *sym, asection **psec, bfd_vma *pvalue, struct elf_link_hash_entry **sym_hash, bfd_boolean *skip, bfd_boolean *override, bfd_boolean *type_change_ok, bfd_boolean *size_change_ok) { asection *sec; struct elf_link_hash_entry *h; struct elf_link_hash_entry *flip; int bind; bfd *oldbfd; bfd_boolean newdyn, olddyn, olddef, newdef, newdyncommon, olddyncommon; bfd_boolean newweak, oldweak; *skip = FALSE; *override = FALSE; sec = *psec; bind = ELF_ST_BIND (sym->st_info); if (! bfd_is_und_section (sec)) h = elf_link_hash_lookup (elf_hash_table (info), name, TRUE, FALSE, FALSE); else h = ((struct elf_link_hash_entry *) bfd_wrapped_link_hash_lookup (abfd, info, name, TRUE, FALSE, FALSE)); if (h == NULL) return FALSE; *sym_hash = h; /* This code is for coping with dynamic objects, and is only useful if we are doing an ELF link. */ if (info->hash->creator != abfd->xvec) return TRUE; /* For merging, we only care about real symbols. */ while (h->root.type == bfd_link_hash_indirect || h->root.type == bfd_link_hash_warning) h = (struct elf_link_hash_entry *) h->root.u.i.link; /* If we just created the symbol, mark it as being an ELF symbol. Other than that, there is nothing to do--there is no merge issue with a newly defined symbol--so we just return. */ if (h->root.type == bfd_link_hash_new) { h->elf_link_hash_flags &=~ ELF_LINK_NON_ELF; return TRUE; } /* OLDBFD is a BFD associated with the existing symbol. */ switch (h->root.type) { default: oldbfd = NULL; break; case bfd_link_hash_undefined: case bfd_link_hash_undefweak: oldbfd = h->root.u.undef.abfd; break; case bfd_link_hash_defined: case bfd_link_hash_defweak: oldbfd = h->root.u.def.section->owner; break; case bfd_link_hash_common: oldbfd = h->root.u.c.p->section->owner; break; } /* In cases involving weak versioned symbols, we may wind up trying to merge a symbol with itself. Catch that here, to avoid the confusion that results if we try to override a symbol with itself. The additional tests catch cases like _GLOBAL_OFFSET_TABLE_, which are regular symbols defined in a dynamic object, which we do want to handle here. */ if (abfd == oldbfd && ((abfd->flags & DYNAMIC) == 0 || (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)) return TRUE; /* NEWDYN and OLDDYN indicate whether the new or old symbol, respectively, is from a dynamic object. */ if ((abfd->flags & DYNAMIC) != 0) newdyn = TRUE; else newdyn = FALSE; if (oldbfd != NULL) olddyn = (oldbfd->flags & DYNAMIC) != 0; else { asection *hsec; /* This code handles the special SHN_MIPS_{TEXT,DATA} section indices used by MIPS ELF. */ switch (h->root.type) { default: hsec = NULL; break; case bfd_link_hash_defined: case bfd_link_hash_defweak: hsec = h->root.u.def.section; break; case bfd_link_hash_common: hsec = h->root.u.c.p->section; break; } if (hsec == NULL) olddyn = FALSE; else olddyn = (hsec->symbol->flags & BSF_DYNAMIC) != 0; } /* NEWDEF and OLDDEF indicate whether the new or old symbol, respectively, appear to be a definition rather than reference. */ if (bfd_is_und_section (sec) || bfd_is_com_section (sec)) newdef = FALSE; else newdef = TRUE; if (h->root.type == bfd_link_hash_undefined || h->root.type == bfd_link_hash_undefweak || h->root.type == bfd_link_hash_common) olddef = FALSE; else olddef = TRUE; /* We need to remember if a symbol has a definition in a dynamic object or is weak in all dynamic objects. Internal and hidden visibility will make it unavailable to dynamic objects. */ if (newdyn && (h->elf_link_hash_flags & ELF_LINK_DYNAMIC_DEF) == 0) { if (!bfd_is_und_section (sec)) h->elf_link_hash_flags |= ELF_LINK_DYNAMIC_DEF; else { /* Check if this symbol is weak in all dynamic objects. If it is the first time we see it in a dynamic object, we mark if it is weak. Otherwise, we clear it. */ if ((h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) == 0) { if (bind == STB_WEAK) h->elf_link_hash_flags |= ELF_LINK_DYNAMIC_WEAK; } else if (bind != STB_WEAK) h->elf_link_hash_flags &= ~ELF_LINK_DYNAMIC_WEAK; } } /* If the old symbol has non-default visibility, we ignore the new definition from a dynamic object. */ if (newdyn && ELF_ST_VISIBILITY (h->other) != STV_DEFAULT && !bfd_is_und_section (sec)) { *skip = TRUE; /* Make sure this symbol is dynamic. */ h->elf_link_hash_flags |= ELF_LINK_HASH_REF_DYNAMIC; /* A protected symbol has external availability. Make sure it is recorded as dynamic. FIXME: Should we check type and size for protected symbol? */ if (ELF_ST_VISIBILITY (h->other) == STV_PROTECTED) return _bfd_elf_link_record_dynamic_symbol (info, h); else return TRUE; } else if (!newdyn && ELF_ST_VISIBILITY (sym->st_other) != STV_DEFAULT && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0) { /* If the new symbol with non-default visibility comes from a relocatable file and the old definition comes from a dynamic object, we remove the old definition. */ if ((*sym_hash)->root.type == bfd_link_hash_indirect) h = *sym_hash; if ((h->root.und_next || info->hash->undefs_tail == &h->root) && bfd_is_und_section (sec)) { /* If the new symbol is undefined and the old symbol was also undefined before, we need to make sure _bfd_generic_link_add_one_symbol doesn't mess up the linker hash table undefs list. Since the old definition came from a dynamic object, it is still on the undefs list. */ h->root.type = bfd_link_hash_undefined; /* FIXME: What if the new symbol is weak undefined? */ h->root.u.undef.abfd = abfd; } else { h->root.type = bfd_link_hash_new; h->root.u.undef.abfd = NULL; } if (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) { h->elf_link_hash_flags &= ~ELF_LINK_HASH_DEF_DYNAMIC; h->elf_link_hash_flags |= (ELF_LINK_HASH_REF_DYNAMIC | ELF_LINK_DYNAMIC_DEF); } /* FIXME: Should we check type and size for protected symbol? */ h->size = 0; h->type = 0; return TRUE; } /* Differentiate strong and weak symbols. */ newweak = bind == STB_WEAK; oldweak = (h->root.type == bfd_link_hash_defweak || h->root.type == bfd_link_hash_undefweak); /* If a new weak symbol comes from a regular file and the old symbol comes from a dynamic library, we treat the new one as strong. Similarly, an old weak symbol from a regular file is treated as strong when the new symbol comes from a dynamic library. Further, an old weak symbol from a dynamic library is treated as strong if the new symbol is from a dynamic library. This reflects the way glibc's ld.so works. */ if (!newdyn && olddyn) newweak = FALSE; if (newdyn) oldweak = FALSE; /* It's OK to change the type if either the existing symbol or the new symbol is weak. A type change is also OK if the old symbol is undefined and the new symbol is defined. */ if (oldweak || newweak || (newdef && h->root.type == bfd_link_hash_undefined)) *type_change_ok = TRUE; /* It's OK to change the size if either the existing symbol or the new symbol is weak, or if the old symbol is undefined. */ if (*type_change_ok || h->root.type == bfd_link_hash_undefined) *size_change_ok = TRUE; /* NEWDYNCOMMON and OLDDYNCOMMON indicate whether the new or old symbol, respectively, appears to be a common symbol in a dynamic object. If a symbol appears in an uninitialized section, and is not weak, and is not a function, then it may be a common symbol which was resolved when the dynamic object was created. We want to treat such symbols specially, because they raise special considerations when setting the symbol size: if the symbol appears as a common symbol in a regular object, and the size in the regular object is larger, we must make sure that we use the larger size. This problematic case can always be avoided in C, but it must be handled correctly when using Fortran shared libraries. Note that if NEWDYNCOMMON is set, NEWDEF will be set, and likewise for OLDDYNCOMMON and OLDDEF. Note that this test is just a heuristic, and that it is quite possible to have an uninitialized symbol in a shared object which is really a definition, rather than a common symbol. This could lead to some minor confusion when the symbol really is a common symbol in some regular object. However, I think it will be harmless. */ if (newdyn && newdef && !newweak && (sec->flags & SEC_ALLOC) != 0 && (sec->flags & SEC_LOAD) == 0 && sym->st_size > 0 && ELF_ST_TYPE (sym->st_info) != STT_FUNC) newdyncommon = TRUE; else newdyncommon = FALSE; if (olddyn && olddef && h->root.type == bfd_link_hash_defined && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0 && (h->root.u.def.section->flags & SEC_ALLOC) != 0 && (h->root.u.def.section->flags & SEC_LOAD) == 0 && h->size > 0 && h->type != STT_FUNC) olddyncommon = TRUE; else olddyncommon = FALSE; /* If both the old and the new symbols look like common symbols in a dynamic object, set the size of the symbol to the larger of the two. */ if (olddyncommon && newdyncommon && sym->st_size != h->size) { /* Since we think we have two common symbols, issue a multiple common warning if desired. Note that we only warn if the size is different. If the size is the same, we simply let the old symbol override the new one as normally happens with symbols defined in dynamic objects. */ if (! ((*info->callbacks->multiple_common) (info, h->root.root.string, oldbfd, bfd_link_hash_common, h->size, abfd, bfd_link_hash_common, sym->st_size))) return FALSE; if (sym->st_size > h->size) h->size = sym->st_size; *size_change_ok = TRUE; } /* If we are looking at a dynamic object, and we have found a definition, we need to see if the symbol was already defined by some other object. If so, we want to use the existing definition, and we do not want to report a multiple symbol definition error; we do this by clobbering *PSEC to be bfd_und_section_ptr. We treat a common symbol as a definition if the symbol in the shared library is a function, since common symbols always represent variables; this can cause confusion in principle, but any such confusion would seem to indicate an erroneous program or shared library. We also permit a common symbol in a regular object to override a weak symbol in a shared object. */ if (newdyn && newdef && (olddef || (h->root.type == bfd_link_hash_common && (newweak || ELF_ST_TYPE (sym->st_info) == STT_FUNC)))) { *override = TRUE; newdef = FALSE; newdyncommon = FALSE; *psec = sec = bfd_und_section_ptr; *size_change_ok = TRUE; /* If we get here when the old symbol is a common symbol, then we are explicitly letting it override a weak symbol or function in a dynamic object, and we don't want to warn about a type change. If the old symbol is a defined symbol, a type change warning may still be appropriate. */ if (h->root.type == bfd_link_hash_common) *type_change_ok = TRUE; } /* Handle the special case of an old common symbol merging with a new symbol which looks like a common symbol in a shared object. We change *PSEC and *PVALUE to make the new symbol look like a common symbol, and let _bfd_generic_link_add_one_symbol will do the right thing. */ if (newdyncommon && h->root.type == bfd_link_hash_common) { *override = TRUE; newdef = FALSE; newdyncommon = FALSE; *pvalue = sym->st_size; *psec = sec = bfd_com_section_ptr; *size_change_ok = TRUE; } /* If the old symbol is from a dynamic object, and the new symbol is a definition which is not from a dynamic object, then the new symbol overrides the old symbol. Symbols from regular files always take precedence over symbols from dynamic objects, even if they are defined after the dynamic object in the link. As above, we again permit a common symbol in a regular object to override a definition in a shared object if the shared object symbol is a function or is weak. */ flip = NULL; if (! newdyn && (newdef || (bfd_is_com_section (sec) && (oldweak || h->type == STT_FUNC))) && olddyn && olddef && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0) { /* Change the hash table entry to undefined, and let _bfd_generic_link_add_one_symbol do the right thing with the new definition. */ h->root.type = bfd_link_hash_undefined; h->root.u.undef.abfd = h->root.u.def.section->owner; *size_change_ok = TRUE; olddef = FALSE; olddyncommon = FALSE; /* We again permit a type change when a common symbol may be overriding a function. */ if (bfd_is_com_section (sec)) *type_change_ok = TRUE; if ((*sym_hash)->root.type == bfd_link_hash_indirect) flip = *sym_hash; else /* This union may have been set to be non-NULL when this symbol was seen in a dynamic object. We must force the union to be NULL, so that it is correct for a regular symbol. */ h->verinfo.vertree = NULL; } /* Handle the special case of a new common symbol merging with an old symbol that looks like it might be a common symbol defined in a shared object. Note that we have already handled the case in which a new common symbol should simply override the definition in the shared library. */ if (! newdyn && bfd_is_com_section (sec) && olddyncommon) { /* It would be best if we could set the hash table entry to a common symbol, but we don't know what to use for the section or the alignment. */ if (! ((*info->callbacks->multiple_common) (info, h->root.root.string, oldbfd, bfd_link_hash_common, h->size, abfd, bfd_link_hash_common, sym->st_size))) return FALSE; /* If the presumed common symbol in the dynamic object is larger, pretend that the new symbol has its size. */ if (h->size > *pvalue) *pvalue = h->size; /* FIXME: We no longer know the alignment required by the symbol in the dynamic object, so we just wind up using the one from the regular object. */ olddef = FALSE; olddyncommon = FALSE; h->root.type = bfd_link_hash_undefined; h->root.u.undef.abfd = h->root.u.def.section->owner; *size_change_ok = TRUE; *type_change_ok = TRUE; if ((*sym_hash)->root.type == bfd_link_hash_indirect) flip = *sym_hash; else h->verinfo.vertree = NULL; } if (flip != NULL) { /* Handle the case where we had a versioned symbol in a dynamic library and now find a definition in a normal object. In this case, we make the versioned symbol point to the normal one. */ const struct elf_backend_data *bed = get_elf_backend_data (abfd); flip->root.type = h->root.type; h->root.type = bfd_link_hash_indirect; h->root.u.i.link = (struct bfd_link_hash_entry *) flip; (*bed->elf_backend_copy_indirect_symbol) (bed, flip, h); flip->root.u.undef.abfd = h->root.u.undef.abfd; if (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) { h->elf_link_hash_flags &= ~ELF_LINK_HASH_DEF_DYNAMIC; flip->elf_link_hash_flags |= ELF_LINK_HASH_REF_DYNAMIC; } } return TRUE; } /* This function is called to create an indirect symbol from the default for the symbol with the default version if needed. The symbol is described by H, NAME, SYM, PSEC, VALUE, and OVERRIDE. We set DYNSYM if the new indirect symbol is dynamic. */ bfd_boolean _bfd_elf_add_default_symbol (bfd *abfd, struct bfd_link_info *info, struct elf_link_hash_entry *h, const char *name, Elf_Internal_Sym *sym, asection **psec, bfd_vma *value, bfd_boolean *dynsym, bfd_boolean override) { bfd_boolean type_change_ok; bfd_boolean size_change_ok; bfd_boolean skip; char *shortname; struct elf_link_hash_entry *hi; struct bfd_link_hash_entry *bh; const struct elf_backend_data *bed; bfd_boolean collect; bfd_boolean dynamic; char *p; size_t len, shortlen; asection *sec; /* If this symbol has a version, and it is the default version, we create an indirect symbol from the default name to the fully decorated name. This will cause external references which do not specify a version to be bound to this version of the symbol. */ p = strchr (name, ELF_VER_CHR); if (p == NULL || p[1] != ELF_VER_CHR) return TRUE; if (override) { /* We are overridden by an old definition. We need to check if we need to create the indirect symbol from the default name. */ hi = elf_link_hash_lookup (elf_hash_table (info), name, TRUE, FALSE, FALSE); BFD_ASSERT (hi != NULL); if (hi == h) return TRUE; while (hi->root.type == bfd_link_hash_indirect || hi->root.type == bfd_link_hash_warning) { hi = (struct elf_link_hash_entry *) hi->root.u.i.link; if (hi == h) return TRUE; } } bed = get_elf_backend_data (abfd); collect = bed->collect; dynamic = (abfd->flags & DYNAMIC) != 0; shortlen = p - name; shortname = bfd_hash_allocate (&info->hash->table, shortlen + 1); if (shortname == NULL) return FALSE; memcpy (shortname, name, shortlen); shortname[shortlen] = '\0'; /* We are going to create a new symbol. Merge it with any existing symbol with this name. For the purposes of the merge, act as though we were defining the symbol we just defined, although we actually going to define an indirect symbol. */ type_change_ok = FALSE; size_change_ok = FALSE; sec = *psec; if (!_bfd_elf_merge_symbol (abfd, info, shortname, sym, &sec, value, &hi, &skip, &override, &type_change_ok, &size_change_ok)) return FALSE; if (skip) goto nondefault; if (! override) { bh = &hi->root; if (! (_bfd_generic_link_add_one_symbol (info, abfd, shortname, BSF_INDIRECT, bfd_ind_section_ptr, 0, name, FALSE, collect, &bh))) return FALSE; hi = (struct elf_link_hash_entry *) bh; } else { /* In this case the symbol named SHORTNAME is overriding the indirect symbol we want to add. We were planning on making SHORTNAME an indirect symbol referring to NAME. SHORTNAME is the name without a version. NAME is the fully versioned name, and it is the default version. Overriding means that we already saw a definition for the symbol SHORTNAME in a regular object, and it is overriding the symbol defined in the dynamic object. When this happens, we actually want to change NAME, the symbol we just added, to refer to SHORTNAME. This will cause references to NAME in the shared object to become references to SHORTNAME in the regular object. This is what we expect when we override a function in a shared object: that the references in the shared object will be mapped to the definition in the regular object. */ while (hi->root.type == bfd_link_hash_indirect || hi->root.type == bfd_link_hash_warning) hi = (struct elf_link_hash_entry *) hi->root.u.i.link; h->root.type = bfd_link_hash_indirect; h->root.u.i.link = (struct bfd_link_hash_entry *) hi; if (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) { h->elf_link_hash_flags &=~ ELF_LINK_HASH_DEF_DYNAMIC; hi->elf_link_hash_flags |= ELF_LINK_HASH_REF_DYNAMIC; if (hi->elf_link_hash_flags & (ELF_LINK_HASH_REF_REGULAR | ELF_LINK_HASH_DEF_REGULAR)) { if (! _bfd_elf_link_record_dynamic_symbol (info, hi)) return FALSE; } } /* Now set HI to H, so that the following code will set the other fields correctly. */ hi = h; } /* If there is a duplicate definition somewhere, then HI may not point to an indirect symbol. We will have reported an error to the user in that case. */ if (hi->root.type == bfd_link_hash_indirect) { struct elf_link_hash_entry *ht; ht = (struct elf_link_hash_entry *) hi->root.u.i.link; (*bed->elf_backend_copy_indirect_symbol) (bed, ht, hi); /* See if the new flags lead us to realize that the symbol must be dynamic. */ if (! *dynsym) { if (! dynamic) { if (info->shared || ((hi->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) != 0)) *dynsym = TRUE; } else { if ((hi->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) != 0) *dynsym = TRUE; } } } /* We also need to define an indirection from the nondefault version of the symbol. */ nondefault: len = strlen (name); shortname = bfd_hash_allocate (&info->hash->table, len); if (shortname == NULL) return FALSE; memcpy (shortname, name, shortlen); memcpy (shortname + shortlen, p + 1, len - shortlen); /* Once again, merge with any existing symbol. */ type_change_ok = FALSE; size_change_ok = FALSE; sec = *psec; if (!_bfd_elf_merge_symbol (abfd, info, shortname, sym, &sec, value, &hi, &skip, &override, &type_change_ok, &size_change_ok)) return FALSE; if (skip) return TRUE; if (override) { /* Here SHORTNAME is a versioned name, so we don't expect to see the type of override we do in the case above unless it is overridden by a versioned definition. */ if (hi->root.type != bfd_link_hash_defined && hi->root.type != bfd_link_hash_defweak) (*_bfd_error_handler) (_("%s: warning: unexpected redefinition of indirect versioned symbol `%s'"), bfd_archive_filename (abfd), shortname); } else { bh = &hi->root; if (! (_bfd_generic_link_add_one_symbol (info, abfd, shortname, BSF_INDIRECT, bfd_ind_section_ptr, 0, name, FALSE, collect, &bh))) return FALSE; hi = (struct elf_link_hash_entry *) bh; /* If there is a duplicate definition somewhere, then HI may not point to an indirect symbol. We will have reported an error to the user in that case. */ if (hi->root.type == bfd_link_hash_indirect) { (*bed->elf_backend_copy_indirect_symbol) (bed, h, hi); /* See if the new flags lead us to realize that the symbol must be dynamic. */ if (! *dynsym) { if (! dynamic) { if (info->shared || ((hi->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) != 0)) *dynsym = TRUE; } else { if ((hi->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) != 0) *dynsym = TRUE; } } } } return TRUE; } /* This routine is used to export all defined symbols into the dynamic symbol table. It is called via elf_link_hash_traverse. */ bfd_boolean _bfd_elf_export_symbol (struct elf_link_hash_entry *h, void *data) { struct elf_info_failed *eif = data; /* Ignore indirect symbols. These are added by the versioning code. */ if (h->root.type == bfd_link_hash_indirect) return TRUE; if (h->root.type == bfd_link_hash_warning) h = (struct elf_link_hash_entry *) h->root.u.i.link; if (h->dynindx == -1 && (h->elf_link_hash_flags & (ELF_LINK_HASH_DEF_REGULAR | ELF_LINK_HASH_REF_REGULAR)) != 0) { struct bfd_elf_version_tree *t; struct bfd_elf_version_expr *d; for (t = eif->verdefs; t != NULL; t = t->next) { if (t->globals.list != NULL) { d = (*t->match) (&t->globals, NULL, h->root.root.string); if (d != NULL) goto doit; } if (t->locals.list != NULL) { d = (*t->match) (&t->locals, NULL, h->root.root.string); if (d != NULL) return TRUE; } } if (!eif->verdefs) { doit: if (! _bfd_elf_link_record_dynamic_symbol (eif->info, h)) { eif->failed = TRUE; return FALSE; } } } return TRUE; } /* Look through the symbols which are defined in other shared libraries and referenced here. Update the list of version dependencies. This will be put into the .gnu.version_r section. This function is called via elf_link_hash_traverse. */ bfd_boolean _bfd_elf_link_find_version_dependencies (struct elf_link_hash_entry *h, void *data) { struct elf_find_verdep_info *rinfo = data; Elf_Internal_Verneed *t; Elf_Internal_Vernaux *a; bfd_size_type amt; if (h->root.type == bfd_link_hash_warning) h = (struct elf_link_hash_entry *) h->root.u.i.link; /* We only care about symbols defined in shared objects with version information. */ if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) == 0 || (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0 || h->dynindx == -1 || h->verinfo.verdef == NULL) return TRUE; /* See if we already know about this version. */ for (t = elf_tdata (rinfo->output_bfd)->verref; t != NULL; t = t->vn_nextref) { if (t->vn_bfd != h->verinfo.verdef->vd_bfd) continue; for (a = t->vn_auxptr; a != NULL; a = a->vna_nextptr) if (a->vna_nodename == h->verinfo.verdef->vd_nodename) return TRUE; break; } /* This is a new version. Add it to tree we are building. */ if (t == NULL) { amt = sizeof *t; t = bfd_zalloc (rinfo->output_bfd, amt); if (t == NULL) { rinfo->failed = TRUE; return FALSE; } t->vn_bfd = h->verinfo.verdef->vd_bfd; t->vn_nextref = elf_tdata (rinfo->output_bfd)->verref; elf_tdata (rinfo->output_bfd)->verref = t; } amt = sizeof *a; a = bfd_zalloc (rinfo->output_bfd, amt); /* Note that we are copying a string pointer here, and testing it above. If bfd_elf_string_from_elf_section is ever changed to discard the string data when low in memory, this will have to be fixed. */ a->vna_nodename = h->verinfo.verdef->vd_nodename; a->vna_flags = h->verinfo.verdef->vd_flags; a->vna_nextptr = t->vn_auxptr; h->verinfo.verdef->vd_exp_refno = rinfo->vers; ++rinfo->vers; a->vna_other = h->verinfo.verdef->vd_exp_refno + 1; t->vn_auxptr = a; return TRUE; } /* Figure out appropriate versions for all the symbols. We may not have the version number script until we have read all of the input files, so until that point we don't know which symbols should be local. This function is called via elf_link_hash_traverse. */ bfd_boolean _bfd_elf_link_assign_sym_version (struct elf_link_hash_entry *h, void *data) { struct elf_assign_sym_version_info *sinfo; struct bfd_link_info *info; const struct elf_backend_data *bed; struct elf_info_failed eif; char *p; bfd_size_type amt; sinfo = data; info = sinfo->info; if (h->root.type == bfd_link_hash_warning) h = (struct elf_link_hash_entry *) h->root.u.i.link; /* Fix the symbol flags. */ eif.failed = FALSE; eif.info = info; if (! _bfd_elf_fix_symbol_flags (h, &eif)) { if (eif.failed) sinfo->failed = TRUE; return FALSE; } /* We only need version numbers for symbols defined in regular objects. */ if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0) return TRUE; bed = get_elf_backend_data (sinfo->output_bfd); p = strchr (h->root.root.string, ELF_VER_CHR); if (p != NULL && h->verinfo.vertree == NULL) { struct bfd_elf_version_tree *t; bfd_boolean hidden; hidden = TRUE; /* There are two consecutive ELF_VER_CHR characters if this is not a hidden symbol. */ ++p; if (*p == ELF_VER_CHR) { hidden = FALSE; ++p; } /* If there is no version string, we can just return out. */ if (*p == '\0') { if (hidden) h->elf_link_hash_flags |= ELF_LINK_HIDDEN; return TRUE; } /* Look for the version. If we find it, it is no longer weak. */ for (t = sinfo->verdefs; t != NULL; t = t->next) { if (strcmp (t->name, p) == 0) { size_t len; char *alc; struct bfd_elf_version_expr *d; len = p - h->root.root.string; alc = bfd_malloc (len); if (alc == NULL) return FALSE; memcpy (alc, h->root.root.string, len - 1); alc[len - 1] = '\0'; if (alc[len - 2] == ELF_VER_CHR) alc[len - 2] = '\0'; h->verinfo.vertree = t; t->used = TRUE; d = NULL; if (t->globals.list != NULL) d = (*t->match) (&t->globals, NULL, alc); /* See if there is anything to force this symbol to local scope. */ if (d == NULL && t->locals.list != NULL) { d = (*t->match) (&t->locals, NULL, alc); if (d != NULL && h->dynindx != -1 && info->shared && ! info->export_dynamic) (*bed->elf_backend_hide_symbol) (info, h, TRUE); } free (alc); break; } } /* If we are building an application, we need to create a version node for this version. */ if (t == NULL && info->executable) { struct bfd_elf_version_tree **pp; int version_index; /* If we aren't going to export this symbol, we don't need to worry about it. */ if (h->dynindx == -1) return TRUE; amt = sizeof *t; t = bfd_zalloc (sinfo->output_bfd, amt); if (t == NULL) { sinfo->failed = TRUE; return FALSE; } t->name = p; t->name_indx = (unsigned int) -1; t->used = TRUE; version_index = 1; /* Don't count anonymous version tag. */ if (sinfo->verdefs != NULL && sinfo->verdefs->vernum == 0) version_index = 0; for (pp = &sinfo->verdefs; *pp != NULL; pp = &(*pp)->next) ++version_index; t->vernum = version_index; *pp = t; h->verinfo.vertree = t; } else if (t == NULL) { /* We could not find the version for a symbol when generating a shared archive. Return an error. */ (*_bfd_error_handler) (_("%s: undefined versioned symbol name %s"), bfd_get_filename (sinfo->output_bfd), h->root.root.string); bfd_set_error (bfd_error_bad_value); sinfo->failed = TRUE; return FALSE; } if (hidden) h->elf_link_hash_flags |= ELF_LINK_HIDDEN; } /* If we don't have a version for this symbol, see if we can find something. */ if (h->verinfo.vertree == NULL && sinfo->verdefs != NULL) { struct bfd_elf_version_tree *t; struct bfd_elf_version_tree *local_ver; struct bfd_elf_version_expr *d; /* See if can find what version this symbol is in. If the symbol is supposed to be local, then don't actually register it. */ local_ver = NULL; for (t = sinfo->verdefs; t != NULL; t = t->next) { if (t->globals.list != NULL) { bfd_boolean matched; matched = FALSE; d = NULL; while ((d = (*t->match) (&t->globals, d, h->root.root.string)) != NULL) if (d->symver) matched = TRUE; else { /* There is a version without definition. Make the symbol the default definition for this version. */ h->verinfo.vertree = t; local_ver = NULL; d->script = 1; break; } if (d != NULL) break; else if (matched) /* There is no undefined version for this symbol. Hide the default one. */ (*bed->elf_backend_hide_symbol) (info, h, TRUE); } if (t->locals.list != NULL) { d = NULL; while ((d = (*t->match) (&t->locals, d, h->root.root.string)) != NULL) { local_ver = t; /* If the match is "*", keep looking for a more explicit, perhaps even global, match. XXX: Shouldn't this be !d->wildcard instead? */ if (d->pattern[0] != '*' || d->pattern[1] != '\0') break; } if (d != NULL) break; } } if (local_ver != NULL) { h->verinfo.vertree = local_ver; if (h->dynindx != -1 && info->shared && ! info->export_dynamic) { (*bed->elf_backend_hide_symbol) (info, h, TRUE); } } } return TRUE; } /* Read and swap the relocs from the section indicated by SHDR. This may be either a REL or a RELA section. The relocations are translated into RELA relocations and stored in INTERNAL_RELOCS, which should have already been allocated to contain enough space. The EXTERNAL_RELOCS are a buffer where the external form of the relocations should be stored. Returns FALSE if something goes wrong. */ static bfd_boolean elf_link_read_relocs_from_section (bfd *abfd, asection *sec, Elf_Internal_Shdr *shdr, void *external_relocs, Elf_Internal_Rela *internal_relocs) { const struct elf_backend_data *bed; void (*swap_in) (bfd *, const bfd_byte *, Elf_Internal_Rela *); const bfd_byte *erela; const bfd_byte *erelaend; Elf_Internal_Rela *irela; Elf_Internal_Shdr *symtab_hdr; size_t nsyms; /* Position ourselves at the start of the section. */ if (bfd_seek (abfd, shdr->sh_offset, SEEK_SET) != 0) return FALSE; /* Read the relocations. */ if (bfd_bread (external_relocs, shdr->sh_size, abfd) != shdr->sh_size) return FALSE; symtab_hdr = &elf_tdata (abfd)->symtab_hdr; nsyms = symtab_hdr->sh_size / symtab_hdr->sh_entsize; bed = get_elf_backend_data (abfd); /* Convert the external relocations to the internal format. */ if (shdr->sh_entsize == bed->s->sizeof_rel) swap_in = bed->s->swap_reloc_in; else if (shdr->sh_entsize == bed->s->sizeof_rela) swap_in = bed->s->swap_reloca_in; else { bfd_set_error (bfd_error_wrong_format); return FALSE; } erela = external_relocs; erelaend = erela + shdr->sh_size; irela = internal_relocs; while (erela < erelaend) { bfd_vma r_symndx; (*swap_in) (abfd, erela, irela); r_symndx = ELF32_R_SYM (irela->r_info); if (bed->s->arch_size == 64) r_symndx >>= 24; if ((size_t) r_symndx >= nsyms) { (*_bfd_error_handler) (_("%s: bad reloc symbol index (0x%lx >= 0x%lx) for offset 0x%lx in section `%s'"), bfd_archive_filename (abfd), (unsigned long) r_symndx, (unsigned long) nsyms, irela->r_offset, sec->name); bfd_set_error (bfd_error_bad_value); return FALSE; } irela += bed->s->int_rels_per_ext_rel; erela += shdr->sh_entsize; } return TRUE; } /* Read and swap the relocs for a section O. They may have been cached. If the EXTERNAL_RELOCS and INTERNAL_RELOCS arguments are not NULL, they are used as buffers to read into. They are known to be large enough. If the INTERNAL_RELOCS relocs argument is NULL, the return value is allocated using either malloc or bfd_alloc, according to the KEEP_MEMORY argument. If O has two relocation sections (both REL and RELA relocations), then the REL_HDR relocations will appear first in INTERNAL_RELOCS, followed by the REL_HDR2 relocations. */ Elf_Internal_Rela * _bfd_elf_link_read_relocs (bfd *abfd, asection *o, void *external_relocs, Elf_Internal_Rela *internal_relocs, bfd_boolean keep_memory) { Elf_Internal_Shdr *rel_hdr; void *alloc1 = NULL; Elf_Internal_Rela *alloc2 = NULL; const struct elf_backend_data *bed = get_elf_backend_data (abfd); if (elf_section_data (o)->relocs != NULL) return elf_section_data (o)->relocs; if (o->reloc_count == 0) return NULL; rel_hdr = &elf_section_data (o)->rel_hdr; if (internal_relocs == NULL) { bfd_size_type size; size = o->reloc_count; size *= bed->s->int_rels_per_ext_rel * sizeof (Elf_Internal_Rela); if (keep_memory) internal_relocs = bfd_alloc (abfd, size); else internal_relocs = alloc2 = bfd_malloc (size); if (internal_relocs == NULL) goto error_return; } if (external_relocs == NULL) { bfd_size_type size = rel_hdr->sh_size; if (elf_section_data (o)->rel_hdr2) size += elf_section_data (o)->rel_hdr2->sh_size; alloc1 = bfd_malloc (size); if (alloc1 == NULL) goto error_return; external_relocs = alloc1; } if (!elf_link_read_relocs_from_section (abfd, o, rel_hdr, external_relocs, internal_relocs)) goto error_return; if (elf_section_data (o)->rel_hdr2 && (!elf_link_read_relocs_from_section (abfd, o, elf_section_data (o)->rel_hdr2, ((bfd_byte *) external_relocs) + rel_hdr->sh_size, internal_relocs + (NUM_SHDR_ENTRIES (rel_hdr) * bed->s->int_rels_per_ext_rel)))) goto error_return; /* Cache the results for next time, if we can. */ if (keep_memory) elf_section_data (o)->relocs = internal_relocs; if (alloc1 != NULL) free (alloc1); /* Don't free alloc2, since if it was allocated we are passing it back (under the name of internal_relocs). */ return internal_relocs; error_return: if (alloc1 != NULL) free (alloc1); if (alloc2 != NULL) free (alloc2); return NULL; } /* Compute the size of, and allocate space for, REL_HDR which is the section header for a section containing relocations for O. */ bfd_boolean _bfd_elf_link_size_reloc_section (bfd *abfd, Elf_Internal_Shdr *rel_hdr, asection *o) { bfd_size_type reloc_count; bfd_size_type num_rel_hashes; /* Figure out how many relocations there will be. */ if (rel_hdr == &elf_section_data (o)->rel_hdr) reloc_count = elf_section_data (o)->rel_count; else reloc_count = elf_section_data (o)->rel_count2; num_rel_hashes = o->reloc_count; if (num_rel_hashes < reloc_count) num_rel_hashes = reloc_count; /* That allows us to calculate the size of the section. */ rel_hdr->sh_size = rel_hdr->sh_entsize * reloc_count; /* The contents field must last into write_object_contents, so we allocate it with bfd_alloc rather than malloc. Also since we cannot be sure that the contents will actually be filled in, we zero the allocated space. */ rel_hdr->contents = bfd_zalloc (abfd, rel_hdr->sh_size); if (rel_hdr->contents == NULL && rel_hdr->sh_size != 0) return FALSE; /* We only allocate one set of hash entries, so we only do it the first time we are called. */ if (elf_section_data (o)->rel_hashes == NULL && num_rel_hashes) { struct elf_link_hash_entry **p; p = bfd_zmalloc (num_rel_hashes * sizeof (struct elf_link_hash_entry *)); if (p == NULL) return FALSE; elf_section_data (o)->rel_hashes = p; } return TRUE; } /* Copy the relocations indicated by the INTERNAL_RELOCS (which originated from the section given by INPUT_REL_HDR) to the OUTPUT_BFD. */ bfd_boolean _bfd_elf_link_output_relocs (bfd *output_bfd, asection *input_section, Elf_Internal_Shdr *input_rel_hdr, Elf_Internal_Rela *internal_relocs) { Elf_Internal_Rela *irela; Elf_Internal_Rela *irelaend; bfd_byte *erel; Elf_Internal_Shdr *output_rel_hdr; asection *output_section; unsigned int *rel_countp = NULL; const struct elf_backend_data *bed; void (*swap_out) (bfd *, const Elf_Internal_Rela *, bfd_byte *); output_section = input_section->output_section; output_rel_hdr = NULL; if (elf_section_data (output_section)->rel_hdr.sh_entsize == input_rel_hdr->sh_entsize) { output_rel_hdr = &elf_section_data (output_section)->rel_hdr; rel_countp = &elf_section_data (output_section)->rel_count; } else if (elf_section_data (output_section)->rel_hdr2 && (elf_section_data (output_section)->rel_hdr2->sh_entsize == input_rel_hdr->sh_entsize)) { output_rel_hdr = elf_section_data (output_section)->rel_hdr2; rel_countp = &elf_section_data (output_section)->rel_count2; } else { (*_bfd_error_handler) (_("%s: relocation size mismatch in %s section %s"), bfd_get_filename (output_bfd), bfd_archive_filename (input_section->owner), input_section->name); bfd_set_error (bfd_error_wrong_object_format); return FALSE; } bed = get_elf_backend_data (output_bfd); if (input_rel_hdr->sh_entsize == bed->s->sizeof_rel) swap_out = bed->s->swap_reloc_out; else if (input_rel_hdr->sh_entsize == bed->s->sizeof_rela) swap_out = bed->s->swap_reloca_out; else abort (); erel = output_rel_hdr->contents; erel += *rel_countp * input_rel_hdr->sh_entsize; irela = internal_relocs; irelaend = irela + (NUM_SHDR_ENTRIES (input_rel_hdr) * bed->s->int_rels_per_ext_rel); while (irela < irelaend) { (*swap_out) (output_bfd, irela, erel); irela += bed->s->int_rels_per_ext_rel; erel += input_rel_hdr->sh_entsize; } /* Bump the counter, so that we know where to add the next set of relocations. */ *rel_countp += NUM_SHDR_ENTRIES (input_rel_hdr); return TRUE; } /* Fix up the flags for a symbol. This handles various cases which can only be fixed after all the input files are seen. This is currently called by both adjust_dynamic_symbol and assign_sym_version, which is unnecessary but perhaps more robust in the face of future changes. */ bfd_boolean _bfd_elf_fix_symbol_flags (struct elf_link_hash_entry *h, struct elf_info_failed *eif) { /* If this symbol was mentioned in a non-ELF file, try to set DEF_REGULAR and REF_REGULAR correctly. This is the only way to permit a non-ELF file to correctly refer to a symbol defined in an ELF dynamic object. */ if ((h->elf_link_hash_flags & ELF_LINK_NON_ELF) != 0) { while (h->root.type == bfd_link_hash_indirect) h = (struct elf_link_hash_entry *) h->root.u.i.link; if (h->root.type != bfd_link_hash_defined && h->root.type != bfd_link_hash_defweak) h->elf_link_hash_flags |= (ELF_LINK_HASH_REF_REGULAR | ELF_LINK_HASH_REF_REGULAR_NONWEAK); else { if (h->root.u.def.section->owner != NULL && (bfd_get_flavour (h->root.u.def.section->owner) == bfd_target_elf_flavour)) h->elf_link_hash_flags |= (ELF_LINK_HASH_REF_REGULAR | ELF_LINK_HASH_REF_REGULAR_NONWEAK); else h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR; } if (h->dynindx == -1 && ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0 || (h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) != 0)) { if (! _bfd_elf_link_record_dynamic_symbol (eif->info, h)) { eif->failed = TRUE; return FALSE; } } } else { /* Unfortunately, ELF_LINK_NON_ELF is only correct if the symbol was first seen in a non-ELF file. Fortunately, if the symbol was first seen in an ELF file, we're probably OK unless the symbol was defined in a non-ELF file. Catch that case here. FIXME: We're still in trouble if the symbol was first seen in a dynamic object, and then later in a non-ELF regular object. */ if ((h->root.type == bfd_link_hash_defined || h->root.type == bfd_link_hash_defweak) && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0 && (h->root.u.def.section->owner != NULL ? (bfd_get_flavour (h->root.u.def.section->owner) != bfd_target_elf_flavour) : (bfd_is_abs_section (h->root.u.def.section) && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) == 0))) h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR; } /* If this is a final link, and the symbol was defined as a common symbol in a regular object file, and there was no definition in any dynamic object, then the linker will have allocated space for the symbol in a common section but the ELF_LINK_HASH_DEF_REGULAR flag will not have been set. */ if (h->root.type == bfd_link_hash_defined && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0 && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) != 0 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) == 0 && (h->root.u.def.section->owner->flags & DYNAMIC) == 0) h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR; /* If -Bsymbolic was used (which means to bind references to global symbols to the definition within the shared object), and this symbol was defined in a regular object, then it actually doesn't need a PLT entry. Likewise, if the symbol has non-default visibility. If the symbol has hidden or internal visibility, we will force it local. */ if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) != 0 && eif->info->shared && is_elf_hash_table (eif->info->hash) && (eif->info->symbolic || ELF_ST_VISIBILITY (h->other) != STV_DEFAULT) && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0) { const struct elf_backend_data *bed; bfd_boolean force_local; bed = get_elf_backend_data (elf_hash_table (eif->info)->dynobj); force_local = (ELF_ST_VISIBILITY (h->other) == STV_INTERNAL || ELF_ST_VISIBILITY (h->other) == STV_HIDDEN); (*bed->elf_backend_hide_symbol) (eif->info, h, force_local); } /* If a weak undefined symbol has non-default visibility, we also hide it from the dynamic linker. */ if (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT && h->root.type == bfd_link_hash_undefweak) { const struct elf_backend_data *bed; bed = get_elf_backend_data (elf_hash_table (eif->info)->dynobj); (*bed->elf_backend_hide_symbol) (eif->info, h, TRUE); } /* If this is a weak defined symbol in a dynamic object, and we know the real definition in the dynamic object, copy interesting flags over to the real definition. */ if (h->weakdef != NULL) { struct elf_link_hash_entry *weakdef; weakdef = h->weakdef; if (h->root.type == bfd_link_hash_indirect) h = (struct elf_link_hash_entry *) h->root.u.i.link; BFD_ASSERT (h->root.type == bfd_link_hash_defined || h->root.type == bfd_link_hash_defweak); BFD_ASSERT (weakdef->root.type == bfd_link_hash_defined || weakdef->root.type == bfd_link_hash_defweak); BFD_ASSERT (weakdef->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC); /* If the real definition is defined by a regular object file, don't do anything special. See the longer description in _bfd_elf_adjust_dynamic_symbol, below. */ if ((weakdef->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0) h->weakdef = NULL; else { const struct elf_backend_data *bed; bed = get_elf_backend_data (elf_hash_table (eif->info)->dynobj); (*bed->elf_backend_copy_indirect_symbol) (bed, weakdef, h); } } return TRUE; } /* Make the backend pick a good value for a dynamic symbol. This is called via elf_link_hash_traverse, and also calls itself recursively. */ bfd_boolean _bfd_elf_adjust_dynamic_symbol (struct elf_link_hash_entry *h, void *data) { struct elf_info_failed *eif = data; bfd *dynobj; const struct elf_backend_data *bed; if (! is_elf_hash_table (eif->info->hash)) return FALSE; if (h->root.type == bfd_link_hash_warning) { h->plt = elf_hash_table (eif->info)->init_offset; h->got = elf_hash_table (eif->info)->init_offset; /* When warning symbols are created, they **replace** the "real" entry in the hash table, thus we never get to see the real symbol in a hash traversal. So look at it now. */ h = (struct elf_link_hash_entry *) h->root.u.i.link; } /* Ignore indirect symbols. These are added by the versioning code. */ if (h->root.type == bfd_link_hash_indirect) return TRUE; /* Fix the symbol flags. */ if (! _bfd_elf_fix_symbol_flags (h, eif)) return FALSE; /* If this symbol does not require a PLT entry, and it is not defined by a dynamic object, or is not referenced by a regular object, ignore it. We do have to handle a weak defined symbol, even if no regular object refers to it, if we decided to add it to the dynamic symbol table. FIXME: Do we normally need to worry about symbols which are defined by one dynamic object and referenced by another one? */ if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) == 0 && ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0 || (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) == 0 || ((h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0 && (h->weakdef == NULL || h->weakdef->dynindx == -1)))) { h->plt = elf_hash_table (eif->info)->init_offset; return TRUE; } /* If we've already adjusted this symbol, don't do it again. This can happen via a recursive call. */ if ((h->elf_link_hash_flags & ELF_LINK_HASH_DYNAMIC_ADJUSTED) != 0) return TRUE; /* Don't look at this symbol again. Note that we must set this after checking the above conditions, because we may look at a symbol once, decide not to do anything, and then get called recursively later after REF_REGULAR is set below. */ h->elf_link_hash_flags |= ELF_LINK_HASH_DYNAMIC_ADJUSTED; /* If this is a weak definition, and we know a real definition, and the real symbol is not itself defined by a regular object file, then get a good value for the real definition. We handle the real symbol first, for the convenience of the backend routine. Note that there is a confusing case here. If the real definition is defined by a regular object file, we don't get the real symbol from the dynamic object, but we do get the weak symbol. If the processor backend uses a COPY reloc, then if some routine in the dynamic object changes the real symbol, we will not see that change in the corresponding weak symbol. This is the way other ELF linkers work as well, and seems to be a result of the shared library model. I will clarify this issue. Most SVR4 shared libraries define the variable _timezone and define timezone as a weak synonym. The tzset call changes _timezone. If you write extern int timezone; int _timezone = 5; int main () { tzset (); printf ("%d %d\n", timezone, _timezone); } you might expect that, since timezone is a synonym for _timezone, the same number will print both times. However, if the processor backend uses a COPY reloc, then actually timezone will be copied into your process image, and, since you define _timezone yourself, _timezone will not. Thus timezone and _timezone will wind up at different memory locations. The tzset call will set _timezone, leaving timezone unchanged. */ if (h->weakdef != NULL) { /* If we get to this point, we know there is an implicit reference by a regular object file via the weak symbol H. FIXME: Is this really true? What if the traversal finds H->WEAKDEF before it finds H? */ h->weakdef->elf_link_hash_flags |= ELF_LINK_HASH_REF_REGULAR; if (! _bfd_elf_adjust_dynamic_symbol (h->weakdef, eif)) return FALSE; } /* If a symbol has no type and no size and does not require a PLT entry, then we are probably about to do the wrong thing here: we are probably going to create a COPY reloc for an empty object. This case can arise when a shared object is built with assembly code, and the assembly code fails to set the symbol type. */ if (h->size == 0 && h->type == STT_NOTYPE && (h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) == 0) (*_bfd_error_handler) (_("warning: type and size of dynamic symbol `%s' are not defined"), h->root.root.string); dynobj = elf_hash_table (eif->info)->dynobj; bed = get_elf_backend_data (dynobj); if (! (*bed->elf_backend_adjust_dynamic_symbol) (eif->info, h)) { eif->failed = TRUE; return FALSE; } return TRUE; } /* Adjust all external symbols pointing into SEC_MERGE sections to reflect the object merging within the sections. */ bfd_boolean _bfd_elf_link_sec_merge_syms (struct elf_link_hash_entry *h, void *data) { asection *sec; if (h->root.type == bfd_link_hash_warning) h = (struct elf_link_hash_entry *) h->root.u.i.link; if ((h->root.type == bfd_link_hash_defined || h->root.type == bfd_link_hash_defweak) && ((sec = h->root.u.def.section)->flags & SEC_MERGE) && sec->sec_info_type == ELF_INFO_TYPE_MERGE) { bfd *output_bfd = data; h->root.u.def.value = _bfd_merged_section_offset (output_bfd, &h->root.u.def.section, elf_section_data (sec)->sec_info, h->root.u.def.value, 0); } return TRUE; } /* Returns false if the symbol referred to by H should be considered to resolve local to the current module, and true if it should be considered to bind dynamically. */ bfd_boolean _bfd_elf_dynamic_symbol_p (struct elf_link_hash_entry *h, struct bfd_link_info *info, bfd_boolean ignore_protected) { bfd_boolean binding_stays_local_p; if (h == NULL) return FALSE; while (h->root.type == bfd_link_hash_indirect || h->root.type == bfd_link_hash_warning) h = (struct elf_link_hash_entry *) h->root.u.i.link; /* If it was forced local, then clearly it's not dynamic. */ if (h->dynindx == -1) return FALSE; if (h->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) return FALSE; /* Identify the cases where name binding rules say that a visible symbol resolves locally. */ binding_stays_local_p = info->executable || info->symbolic; switch (ELF_ST_VISIBILITY (h->other)) { case STV_INTERNAL: case STV_HIDDEN: return FALSE; case STV_PROTECTED: /* Proper resolution for function pointer equality may require that these symbols perhaps be resolved dynamically, even though we should be resolving them to the current module. */ if (!ignore_protected) binding_stays_local_p = TRUE; break; default: break; } /* If it isn't defined locally, then clearly it's dynamic. */ if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0) return TRUE; /* Otherwise, the symbol is dynamic if binding rules don't tell us that it remains local. */ return !binding_stays_local_p; } /* Return true if the symbol referred to by H should be considered to resolve local to the current module, and false otherwise. Differs from (the inverse of) _bfd_elf_dynamic_symbol_p in the treatment of undefined symbols and weak symbols. */ bfd_boolean _bfd_elf_symbol_refs_local_p (struct elf_link_hash_entry *h, struct bfd_link_info *info, bfd_boolean local_protected) { /* If it's a local sym, of course we resolve locally. */ if (h == NULL) return TRUE; /* If we don't have a definition in a regular file, then we can't resolve locally. The sym is either undefined or dynamic. */ if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0) return FALSE; /* Forced local symbols resolve locally. */ if ((h->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) != 0) return TRUE; /* As do non-dynamic symbols. */ if (h->dynindx == -1) return TRUE; /* At this point, we know the symbol is defined and dynamic. In an executable it must resolve locally, likewise when building symbolic shared libraries. */ if (info->executable || info->symbolic) return TRUE; /* Now deal with defined dynamic symbols in shared libraries. Ones with default visibility might not resolve locally. */ if (ELF_ST_VISIBILITY (h->other) == STV_DEFAULT) return FALSE; /* However, STV_HIDDEN or STV_INTERNAL ones must be local. */ if (ELF_ST_VISIBILITY (h->other) != STV_PROTECTED) return TRUE; /* Function pointer equality tests may require that STV_PROTECTED symbols be treated as dynamic symbols, even when we know that the dynamic linker will resolve them locally. */ return local_protected; } /* Caches some TLS segment info, and ensures that the TLS segment vma is aligned. Returns the first TLS output section. */ struct bfd_section * _bfd_elf_tls_setup (bfd *obfd, struct bfd_link_info *info) { struct bfd_section *sec, *tls; unsigned int align = 0; for (sec = obfd->sections; sec != NULL; sec = sec->next) if ((sec->flags & SEC_THREAD_LOCAL) != 0) break; tls = sec; for (; sec != NULL && (sec->flags & SEC_THREAD_LOCAL) != 0; sec = sec->next) if (sec->alignment_power > align) align = sec->alignment_power; elf_hash_table (info)->tls_sec = tls; /* Ensure the alignment of the first section is the largest alignment, so that the tls segment starts aligned. */ if (tls != NULL) tls->alignment_power = align; return tls; } /* Return TRUE iff this is a non-common, definition of a non-function symbol. */ static bfd_boolean is_global_data_symbol_definition (bfd *abfd ATTRIBUTE_UNUSED, Elf_Internal_Sym *sym) { /* Local symbols do not count, but target specific ones might. */ if (ELF_ST_BIND (sym->st_info) != STB_GLOBAL && ELF_ST_BIND (sym->st_info) < STB_LOOS) return FALSE; /* Function symbols do not count. */ if (ELF_ST_TYPE (sym->st_info) == STT_FUNC) return FALSE; /* If the section is undefined, then so is the symbol. */ if (sym->st_shndx == SHN_UNDEF) return FALSE; /* If the symbol is defined in the common section, then it is a common definition and so does not count. */ if (sym->st_shndx == SHN_COMMON) return FALSE; /* If the symbol is in a target specific section then we must rely upon the backend to tell us what it is. */ if (sym->st_shndx >= SHN_LORESERVE && sym->st_shndx < SHN_ABS) /* FIXME - this function is not coded yet: return _bfd_is_global_symbol_definition (abfd, sym); Instead for now assume that the definition is not global, Even if this is wrong, at least the linker will behave in the same way that it used to do. */ return FALSE; return TRUE; } /* Search the symbol table of the archive element of the archive ABFD whose archive map contains a mention of SYMDEF, and determine if the symbol is defined in this element. */ static bfd_boolean elf_link_is_defined_archive_symbol (bfd * abfd, carsym * symdef) { Elf_Internal_Shdr * hdr; bfd_size_type symcount; bfd_size_type extsymcount; bfd_size_type extsymoff; Elf_Internal_Sym *isymbuf; Elf_Internal_Sym *isym; Elf_Internal_Sym *isymend; bfd_boolean result; abfd = _bfd_get_elt_at_filepos (abfd, symdef->file_offset); if (abfd == NULL) return FALSE; if (! bfd_check_format (abfd, bfd_object)) return FALSE; /* If we have already included the element containing this symbol in the link then we do not need to include it again. Just claim that any symbol it contains is not a definition, so that our caller will not decide to (re)include this element. */ if (abfd->archive_pass) return FALSE; /* Select the appropriate symbol table. */ if ((abfd->flags & DYNAMIC) == 0 || elf_dynsymtab (abfd) == 0) hdr = &elf_tdata (abfd)->symtab_hdr; else hdr = &elf_tdata (abfd)->dynsymtab_hdr; symcount = hdr->sh_size / get_elf_backend_data (abfd)->s->sizeof_sym; /* The sh_info field of the symtab header tells us where the external symbols start. We don't care about the local symbols. */ if (elf_bad_symtab (abfd)) { extsymcount = symcount; extsymoff = 0; } else { extsymcount = symcount - hdr->sh_info; extsymoff = hdr->sh_info; } if (extsymcount == 0) return FALSE; /* Read in the symbol table. */ isymbuf = bfd_elf_get_elf_syms (abfd, hdr, extsymcount, extsymoff, NULL, NULL, NULL); if (isymbuf == NULL) return FALSE; /* Scan the symbol table looking for SYMDEF. */ result = FALSE; for (isym = isymbuf, isymend = isymbuf + extsymcount; isym < isymend; isym++) { const char *name; name = bfd_elf_string_from_elf_section (abfd, hdr->sh_link, isym->st_name); if (name == NULL) break; if (strcmp (name, symdef->name) == 0) { result = is_global_data_symbol_definition (abfd, isym); break; } } free (isymbuf); return result; } /* Add symbols from an ELF archive file to the linker hash table. We don't use _bfd_generic_link_add_archive_symbols because of a problem which arises on UnixWare. The UnixWare libc.so is an archive which includes an entry libc.so.1 which defines a bunch of symbols. The libc.so archive also includes a number of other object files, which also define symbols, some of which are the same as those defined in libc.so.1. Correct linking requires that we consider each object file in turn, and include it if it defines any symbols we need. _bfd_generic_link_add_archive_symbols does not do this; it looks through the list of undefined symbols, and includes any object file which defines them. When this algorithm is used on UnixWare, it winds up pulling in libc.so.1 early and defining a bunch of symbols. This means that some of the other objects in the archive are not included in the link, which is incorrect since they precede libc.so.1 in the archive. Fortunately, ELF archive handling is simpler than that done by _bfd_generic_link_add_archive_symbols, which has to allow for a.out oddities. In ELF, if we find a symbol in the archive map, and the symbol is currently undefined, we know that we must pull in that object file. Unfortunately, we do have to make multiple passes over the symbol table until nothing further is resolved. */ bfd_boolean _bfd_elf_link_add_archive_symbols (bfd *abfd, struct bfd_link_info *info) { symindex c; bfd_boolean *defined = NULL; bfd_boolean *included = NULL; carsym *symdefs; bfd_boolean loop; bfd_size_type amt; if (! bfd_has_map (abfd)) { /* An empty archive is a special case. */ if (bfd_openr_next_archived_file (abfd, NULL) == NULL) return TRUE; bfd_set_error (bfd_error_no_armap); return FALSE; } /* Keep track of all symbols we know to be already defined, and all files we know to be already included. This is to speed up the second and subsequent passes. */ c = bfd_ardata (abfd)->symdef_count; if (c == 0) return TRUE; amt = c; amt *= sizeof (bfd_boolean); defined = bfd_zmalloc (amt); included = bfd_zmalloc (amt); if (defined == NULL || included == NULL) goto error_return; symdefs = bfd_ardata (abfd)->symdefs; do { file_ptr last; symindex i; carsym *symdef; carsym *symdefend; loop = FALSE; last = -1; symdef = symdefs; symdefend = symdef + c; for (i = 0; symdef < symdefend; symdef++, i++) { struct elf_link_hash_entry *h; bfd *element; struct bfd_link_hash_entry *undefs_tail; symindex mark; if (defined[i] || included[i]) continue; if (symdef->file_offset == last) { included[i] = TRUE; continue; } h = elf_link_hash_lookup (elf_hash_table (info), symdef->name, FALSE, FALSE, FALSE); if (h == NULL) { char *p, *copy; size_t len, first; /* If this is a default version (the name contains @@), look up the symbol again with only one `@' as well as without the version. The effect is that references to the symbol with and without the version will be matched by the default symbol in the archive. */ p = strchr (symdef->name, ELF_VER_CHR); if (p == NULL || p[1] != ELF_VER_CHR) continue; /* First check with only one `@'. */ len = strlen (symdef->name); copy = bfd_alloc (abfd, len); if (copy == NULL) goto error_return; first = p - symdef->name + 1; memcpy (copy, symdef->name, first); memcpy (copy + first, symdef->name + first + 1, len - first); h = elf_link_hash_lookup (elf_hash_table (info), copy, FALSE, FALSE, FALSE); if (h == NULL) { /* We also need to check references to the symbol without the version. */ copy[first - 1] = '\0'; h = elf_link_hash_lookup (elf_hash_table (info), copy, FALSE, FALSE, FALSE); } bfd_release (abfd, copy); } if (h == NULL) continue; if (h->root.type == bfd_link_hash_common) { /* We currently have a common symbol. The archive map contains a reference to this symbol, so we may want to include it. We only want to include it however, if this archive element contains a definition of the symbol, not just another common declaration of it. Unfortunately some archivers (including GNU ar) will put declarations of common symbols into their archive maps, as well as real definitions, so we cannot just go by the archive map alone. Instead we must read in the element's symbol table and check that to see what kind of symbol definition this is. */ if (! elf_link_is_defined_archive_symbol (abfd, symdef)) continue; } else if (h->root.type != bfd_link_hash_undefined) { if (h->root.type != bfd_link_hash_undefweak) defined[i] = TRUE; continue; } /* We need to include this archive member. */ element = _bfd_get_elt_at_filepos (abfd, symdef->file_offset); if (element == NULL) goto error_return; if (! bfd_check_format (element, bfd_object)) goto error_return; /* Doublecheck that we have not included this object already--it should be impossible, but there may be something wrong with the archive. */ if (element->archive_pass != 0) { bfd_set_error (bfd_error_bad_value); goto error_return; } element->archive_pass = 1; undefs_tail = info->hash->undefs_tail; if (! (*info->callbacks->add_archive_element) (info, element, symdef->name)) goto error_return; if (! bfd_link_add_symbols (element, info)) goto error_return; /* If there are any new undefined symbols, we need to make another pass through the archive in order to see whether they can be defined. FIXME: This isn't perfect, because common symbols wind up on undefs_tail and because an undefined symbol which is defined later on in this pass does not require another pass. This isn't a bug, but it does make the code less efficient than it could be. */ if (undefs_tail != info->hash->undefs_tail) loop = TRUE; /* Look backward to mark all symbols from this object file which we have already seen in this pass. */ mark = i; do { included[mark] = TRUE; if (mark == 0) break; --mark; } while (symdefs[mark].file_offset == symdef->file_offset); /* We mark subsequent symbols from this object file as we go on through the loop. */ last = symdef->file_offset; } } while (loop); free (defined); free (included); return TRUE; error_return: if (defined != NULL) free (defined); if (included != NULL) free (included); return FALSE; }