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/* ELF linker support. Copyright 1995, 1996, 1997, 1998, 1999, 2000, 2001 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. */ /* ELF linker code. */ /* This struct is used to pass information to routines called via elf_link_hash_traverse which must return failure. */ struct elf_info_failed { boolean failed; struct bfd_link_info *info; struct bfd_elf_version_tree *verdefs; }; static boolean elf_link_add_object_symbols PARAMS ((bfd *, struct bfd_link_info *)); static boolean elf_link_add_archive_symbols PARAMS ((bfd *, struct bfd_link_info *)); static boolean elf_merge_symbol PARAMS ((bfd *, struct bfd_link_info *, const char *, Elf_Internal_Sym *, asection **, bfd_vma *, struct elf_link_hash_entry **, boolean *, boolean *, boolean *, boolean)); static boolean elf_export_symbol PARAMS ((struct elf_link_hash_entry *, PTR)); static boolean elf_fix_symbol_flags PARAMS ((struct elf_link_hash_entry *, struct elf_info_failed *)); static boolean elf_adjust_dynamic_symbol PARAMS ((struct elf_link_hash_entry *, PTR)); static boolean elf_link_find_version_dependencies PARAMS ((struct elf_link_hash_entry *, PTR)); static boolean elf_link_find_version_dependencies PARAMS ((struct elf_link_hash_entry *, PTR)); static boolean elf_link_assign_sym_version PARAMS ((struct elf_link_hash_entry *, PTR)); static boolean elf_collect_hash_codes PARAMS ((struct elf_link_hash_entry *, PTR)); static boolean elf_link_read_relocs_from_section PARAMS ((bfd *, Elf_Internal_Shdr *, PTR, Elf_Internal_Rela *)); static void elf_link_output_relocs PARAMS ((bfd *, asection *, Elf_Internal_Shdr *, Elf_Internal_Rela *)); static boolean elf_link_size_reloc_section PARAMS ((bfd *, Elf_Internal_Shdr *, asection *)); static void elf_link_adjust_relocs PARAMS ((bfd *, Elf_Internal_Shdr *, unsigned int, struct elf_link_hash_entry **)); /* Given an ELF BFD, add symbols to the global hash table as appropriate. */ boolean elf_bfd_link_add_symbols (abfd, info) bfd *abfd; struct bfd_link_info *info; { switch (bfd_get_format (abfd)) { case bfd_object: return elf_link_add_object_symbols (abfd, info); case bfd_archive: return elf_link_add_archive_symbols (abfd, info); default: bfd_set_error (bfd_error_wrong_format); return false; } } /* Return true iff this is a non-common, definition of a non-function symbol. */ static boolean is_global_data_symbol_definition (abfd, sym) 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 boolean elf_link_is_defined_archive_symbol (abfd, symdef) bfd * abfd; carsym * symdef; { Elf_Internal_Shdr * hdr; Elf_External_Sym * esym; Elf_External_Sym * esymend; Elf_External_Sym * buf = NULL; size_t symcount; size_t extsymcount; size_t extsymoff; boolean result = false; abfd = _bfd_get_elt_at_filepos (abfd, symdef->file_offset); if (abfd == (bfd *) 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 / sizeof (Elf_External_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; } buf = ((Elf_External_Sym *) bfd_malloc (extsymcount * sizeof (Elf_External_Sym))); if (buf == NULL && extsymcount != 0) return false; /* Read in the symbol table. FIXME: This ought to be cached somewhere. */ if (bfd_seek (abfd, hdr->sh_offset + extsymoff * sizeof (Elf_External_Sym), SEEK_SET) != 0 || (bfd_read ((PTR) buf, sizeof (Elf_External_Sym), extsymcount, abfd) != extsymcount * sizeof (Elf_External_Sym))) { free (buf); return false; } /* Scan the symbol table looking for SYMDEF. */ esymend = buf + extsymcount; for (esym = buf; esym < esymend; esym++) { Elf_Internal_Sym sym; const char * name; elf_swap_symbol_in (abfd, esym, & sym); name = bfd_elf_string_from_elf_section (abfd, hdr->sh_link, sym.st_name); if (name == (const char *) NULL) break; if (strcmp (name, symdef->name) == 0) { result = is_global_data_symbol_definition (abfd, & sym); break; } } free (buf); 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. */ static boolean elf_link_add_archive_symbols (abfd, info) bfd *abfd; struct bfd_link_info *info; { symindex c; boolean *defined = NULL; boolean *included = NULL; carsym *symdefs; boolean loop; if (! bfd_has_map (abfd)) { /* An empty archive is a special case. */ if (bfd_openr_next_archived_file (abfd, (bfd *) 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; defined = (boolean *) bfd_malloc (c * sizeof (boolean)); included = (boolean *) bfd_malloc (c * sizeof (boolean)); if (defined == (boolean *) NULL || included == (boolean *) NULL) goto error_return; memset (defined, 0, c * sizeof (boolean)); memset (included, 0, c * sizeof (boolean)); 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; /* If this is a default version (the name contains @@), look up the symbol again without the version. The effect is that references to the symbol 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; copy = bfd_alloc (abfd, p - symdef->name + 1); if (copy == NULL) goto error_return; memcpy (copy, symdef->name, p - symdef->name); copy[p - symdef->name] = '\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 == (bfd *) 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 (! elf_link_add_object_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 != (boolean *) NULL) free (defined); if (included != (boolean *) NULL) free (included); return false; } /* 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. DT_NEEDED indicates if it comes from a DT_NEEDED entry of a shared object. */ static boolean elf_merge_symbol (abfd, info, name, sym, psec, pvalue, sym_hash, override, type_change_ok, size_change_ok, dt_needed) 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; boolean *override; boolean *type_change_ok; boolean *size_change_ok; boolean dt_needed; { asection *sec; struct elf_link_hash_entry *h; int bind; bfd *oldbfd; boolean newdyn, olddyn, olddef, newdef, newdyncommon, olddyncommon; *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; /* 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 && (sec->flags & SEC_ALLOC) != 0 && (sec->flags & SEC_LOAD) == 0 && sym->st_size > 0 && bind != STB_WEAK && 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; /* It's OK to change the type if either the existing symbol or the new symbol is weak unless it comes from a DT_NEEDED entry of a shared object, in which case, the DT_NEEDED entry may not be required at the run time. */ if ((! dt_needed && h->root.type == bfd_link_hash_defweak) || h->root.type == bfd_link_hash_undefweak || bind == STB_WEAK) *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; /* 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. We prefer a non-weak definition in a shared library to a weak definition in the executable unless it comes from a DT_NEEDED entry of a shared object, in which case, the DT_NEEDED entry may not be required at the run time. */ if (newdyn && newdef && (olddef || (h->root.type == bfd_link_hash_common && (bind == STB_WEAK || ELF_ST_TYPE (sym->st_info) == STT_FUNC))) && (h->root.type != bfd_link_hash_defweak || dt_needed || bind == STB_WEAK)) { *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. As above, we permit a non-weak definition in a shared object to override a weak definition in a regular object. */ if (! newdyn && (newdef || (bfd_is_com_section (sec) && (h->root.type == bfd_link_hash_defweak || h->type == STT_FUNC))) && olddyn && olddef && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0 && (bind != STB_WEAK || h->root.type == bfd_link_hash_defweak)) { /* 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; /* 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; /* In this special case, if H is the target of an indirection, we want the caller to frob with H rather than with the indirect symbol. That will permit the caller to redefine the target of the indirection, rather than the indirect symbol itself. FIXME: This will break the -y option if we store a symbol with a different name. */ *sym_hash = h; } /* 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 predumed 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; h->verinfo.vertree = NULL; } /* Handle the special case of a weak definition in a regular object followed by a non-weak definition in a shared object. In this case, we prefer the definition in the shared object unless it comes from a DT_NEEDED entry of a shared object, in which case, the DT_NEEDED entry may not be required at the run time. */ if (olddef && ! dt_needed && h->root.type == bfd_link_hash_defweak && newdef && newdyn && bind != STB_WEAK) { /* To make this work we have to frob the flags so that the rest of the code does not think we are using the regular definition. */ if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0) h->elf_link_hash_flags |= ELF_LINK_HASH_REF_REGULAR; else if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0) h->elf_link_hash_flags |= ELF_LINK_HASH_REF_DYNAMIC; h->elf_link_hash_flags &= ~ (ELF_LINK_HASH_DEF_REGULAR | ELF_LINK_HASH_DEF_DYNAMIC); /* If H is the target of an indirection, we want the caller to use H rather than the indirect symbol. Otherwise if we are defining a new indirect symbol we will wind up attaching it to the entry we are overriding. */ *sym_hash = h; } /* Handle the special case of a non-weak definition in a shared object followed by a weak definition in a regular object. In this case we prefer to definition in the shared object. To make this work we have to tell the caller to not treat the new symbol as a definition. */ if (olddef && olddyn && h->root.type != bfd_link_hash_defweak && newdef && ! newdyn && bind == STB_WEAK) *override = true; return true; } /* Add symbols from an ELF object file to the linker hash table. */ static boolean elf_link_add_object_symbols (abfd, info) bfd *abfd; struct bfd_link_info *info; { boolean (*add_symbol_hook) PARAMS ((bfd *, struct bfd_link_info *, const Elf_Internal_Sym *, const char **, flagword *, asection **, bfd_vma *)); boolean (*check_relocs) PARAMS ((bfd *, struct bfd_link_info *, asection *, const Elf_Internal_Rela *)); boolean collect; Elf_Internal_Shdr *hdr; size_t symcount; size_t extsymcount; size_t extsymoff; Elf_External_Sym *buf = NULL; struct elf_link_hash_entry **sym_hash; boolean dynamic; Elf_External_Versym *extversym = NULL; Elf_External_Versym *ever; Elf_External_Dyn *dynbuf = NULL; struct elf_link_hash_entry *weaks; Elf_External_Sym *esym; Elf_External_Sym *esymend; struct elf_backend_data *bed; boolean dt_needed; bed = get_elf_backend_data (abfd); add_symbol_hook = bed->elf_add_symbol_hook; collect = bed->collect; if ((abfd->flags & DYNAMIC) == 0) dynamic = false; else { dynamic = true; /* You can't use -r against a dynamic object. Also, there's no hope of using a dynamic object which does not exactly match the format of the output file. */ if (info->relocateable || info->hash->creator != abfd->xvec) { bfd_set_error (bfd_error_invalid_operation); goto error_return; } } /* As a GNU extension, any input sections which are named .gnu.warning.SYMBOL are treated as warning symbols for the given symbol. This differs from .gnu.warning sections, which generate warnings when they are included in an output file. */ if (! info->shared) { asection *s; for (s = abfd->sections; s != NULL; s = s->next) { const char *name; name = bfd_get_section_name (abfd, s); if (strncmp (name, ".gnu.warning.", sizeof ".gnu.warning." - 1) == 0) { char *msg; bfd_size_type sz; name += sizeof ".gnu.warning." - 1; /* If this is a shared object, then look up the symbol in the hash table. If it is there, and it is already been defined, then we will not be using the entry from this shared object, so we don't need to warn. FIXME: If we see the definition in a regular object later on, we will warn, but we shouldn't. The only fix is to keep track of what warnings we are supposed to emit, and then handle them all at the end of the link. */ if (dynamic && abfd->xvec == info->hash->creator) { struct elf_link_hash_entry *h; h = elf_link_hash_lookup (elf_hash_table (info), name, false, false, true); /* FIXME: What about bfd_link_hash_common? */ if (h != NULL && (h->root.type == bfd_link_hash_defined || h->root.type == bfd_link_hash_defweak)) { /* We don't want to issue this warning. Clobber the section size so that the warning does not get copied into the output file. */ s->_raw_size = 0; continue; } } sz = bfd_section_size (abfd, s); msg = (char *) bfd_alloc (abfd, sz + 1); if (msg == NULL) goto error_return; if (! bfd_get_section_contents (abfd, s, msg, (file_ptr) 0, sz)) goto error_return; msg[sz] = '\0'; if (! (_bfd_generic_link_add_one_symbol (info, abfd, name, BSF_WARNING, s, (bfd_vma) 0, msg, false, collect, (struct bfd_link_hash_entry **) NULL))) goto error_return; if (! info->relocateable) { /* Clobber the section size so that the warning does not get copied into the output file. */ s->_raw_size = 0; } } } } /* If this is a dynamic object, we always link against the .dynsym symbol table, not the .symtab symbol table. The dynamic linker will only see the .dynsym symbol table, so there is no reason to look at .symtab for a dynamic object. */ if (! dynamic || elf_dynsymtab (abfd) == 0) hdr = &elf_tdata (abfd)->symtab_hdr; else hdr = &elf_tdata (abfd)->dynsymtab_hdr; if (dynamic) { /* Read in any version definitions. */ if (! _bfd_elf_slurp_version_tables (abfd)) goto error_return; /* Read in the symbol versions, but don't bother to convert them to internal format. */ if (elf_dynversym (abfd) != 0) { Elf_Internal_Shdr *versymhdr; versymhdr = &elf_tdata (abfd)->dynversym_hdr; extversym = (Elf_External_Versym *) bfd_malloc (versymhdr->sh_size); if (extversym == NULL) goto error_return; if (bfd_seek (abfd, versymhdr->sh_offset, SEEK_SET) != 0 || (bfd_read ((PTR) extversym, 1, versymhdr->sh_size, abfd) != versymhdr->sh_size)) goto error_return; } } symcount = hdr->sh_size / sizeof (Elf_External_Sym); /* The sh_info field of the symtab header tells us where the external symbols start. We don't care about the local symbols at this point. */ if (elf_bad_symtab (abfd)) { extsymcount = symcount; extsymoff = 0; } else { extsymcount = symcount - hdr->sh_info; extsymoff = hdr->sh_info; } buf = ((Elf_External_Sym *) bfd_malloc (extsymcount * sizeof (Elf_External_Sym))); if (buf == NULL && extsymcount != 0) goto error_return; /* We store a pointer to the hash table entry for each external symbol. */ sym_hash = ((struct elf_link_hash_entry **) bfd_alloc (abfd, extsymcount * sizeof (struct elf_link_hash_entry *))); if (sym_hash == NULL) goto error_return; elf_sym_hashes (abfd) = sym_hash; dt_needed = false; if (! dynamic) { /* If we are creating a shared library, create all the dynamic sections immediately. We need to attach them to something, so we attach them to this BFD, provided it is the right format. FIXME: If there are no input BFD's of the same format as the output, we can't make a shared library. */ if (info->shared && ! elf_hash_table (info)->dynamic_sections_created && abfd->xvec == info->hash->creator) { if (! elf_link_create_dynamic_sections (abfd, info)) goto error_return; } } else { asection *s; boolean add_needed; const char *name; bfd_size_type oldsize; bfd_size_type strindex; /* Find the name to use in a DT_NEEDED entry that refers to this object. If the object has a DT_SONAME entry, we use it. Otherwise, if the generic linker stuck something in elf_dt_name, we use that. Otherwise, we just use the file name. If the generic linker put a null string into elf_dt_name, we don't make a DT_NEEDED entry at all, even if there is a DT_SONAME entry. */ add_needed = true; name = bfd_get_filename (abfd); if (elf_dt_name (abfd) != NULL) { name = elf_dt_name (abfd); if (*name == '\0') { if (elf_dt_soname (abfd) != NULL) dt_needed = true; add_needed = false; } } s = bfd_get_section_by_name (abfd, ".dynamic"); if (s != NULL) { Elf_External_Dyn *extdyn; Elf_External_Dyn *extdynend; int elfsec; unsigned long link; int rpath; int runpath; dynbuf = (Elf_External_Dyn *) bfd_malloc ((size_t) s->_raw_size); if (dynbuf == NULL) goto error_return; if (! bfd_get_section_contents (abfd, s, (PTR) dynbuf, (file_ptr) 0, s->_raw_size)) goto error_return; elfsec = _bfd_elf_section_from_bfd_section (abfd, s); if (elfsec == -1) goto error_return; link = elf_elfsections (abfd)[elfsec]->sh_link; { /* The shared libraries distributed with hpux11 have a bogus sh_link field for the ".dynamic" section. This code detects when LINK refers to a section that is not a string table and tries to find the string table for the ".dynsym" section instead. */ Elf_Internal_Shdr *hdr = elf_elfsections (abfd)[link]; if (hdr->sh_type != SHT_STRTAB) { asection *s = bfd_get_section_by_name (abfd, ".dynsym"); int elfsec = _bfd_elf_section_from_bfd_section (abfd, s); if (elfsec == -1) goto error_return; link = elf_elfsections (abfd)[elfsec]->sh_link; } } extdyn = dynbuf; extdynend = extdyn + s->_raw_size / sizeof (Elf_External_Dyn); rpath = 0; runpath = 0; for (; extdyn < extdynend; extdyn++) { Elf_Internal_Dyn dyn; elf_swap_dyn_in (abfd, extdyn, &dyn); if (dyn.d_tag == DT_SONAME) { name = bfd_elf_string_from_elf_section (abfd, link, dyn.d_un.d_val); if (name == NULL) goto error_return; } if (dyn.d_tag == DT_NEEDED) { struct bfd_link_needed_list *n, **pn; char *fnm, *anm; n = ((struct bfd_link_needed_list *) bfd_alloc (abfd, sizeof (struct bfd_link_needed_list))); fnm = bfd_elf_string_from_elf_section (abfd, link, dyn.d_un.d_val); if (n == NULL || fnm == NULL) goto error_return; anm = bfd_alloc (abfd, strlen (fnm) + 1); if (anm == NULL) goto error_return; strcpy (anm, fnm); n->name = anm; n->by = abfd; n->next = NULL; for (pn = &elf_hash_table (info)->needed; *pn != NULL; pn = &(*pn)->next) ; *pn = n; } if (dyn.d_tag == DT_RUNPATH) { struct bfd_link_needed_list *n, **pn; char *fnm, *anm; /* When we see DT_RPATH before DT_RUNPATH, we have to clear runpath. Do _NOT_ bfd_release, as that frees all more recently bfd_alloc'd blocks as well. */ if (rpath && elf_hash_table (info)->runpath) elf_hash_table (info)->runpath = NULL; n = ((struct bfd_link_needed_list *) bfd_alloc (abfd, sizeof (struct bfd_link_needed_list))); fnm = bfd_elf_string_from_elf_section (abfd, link, dyn.d_un.d_val); if (n == NULL || fnm == NULL) goto error_return; anm = bfd_alloc (abfd, strlen (fnm) + 1); if (anm == NULL) goto error_return; strcpy (anm, fnm); n->name = anm; n->by = abfd; n->next = NULL; for (pn = &elf_hash_table (info)->runpath; *pn != NULL; pn = &(*pn)->next) ; *pn = n; runpath = 1; rpath = 0; } /* Ignore DT_RPATH if we have seen DT_RUNPATH. */ if (!runpath && dyn.d_tag == DT_RPATH) { struct bfd_link_needed_list *n, **pn; char *fnm, *anm; n = ((struct bfd_link_needed_list *) bfd_alloc (abfd, sizeof (struct bfd_link_needed_list))); fnm = bfd_elf_string_from_elf_section (abfd, link, dyn.d_un.d_val); if (n == NULL || fnm == NULL) goto error_return; anm = bfd_alloc (abfd, strlen (fnm) + 1); if (anm == NULL) goto error_return; strcpy (anm, fnm); n->name = anm; n->by = abfd; n->next = NULL; for (pn = &elf_hash_table (info)->runpath; *pn != NULL; pn = &(*pn)->next) ; *pn = n; rpath = 1; } } free (dynbuf); dynbuf = NULL; } /* We do not want to include any of the sections in a dynamic object in the output file. We hack by simply clobbering the list of sections in the BFD. This could be handled more cleanly by, say, a new section flag; the existing SEC_NEVER_LOAD flag is not the one we want, because that one still implies that the section takes up space in the output file. */ abfd->sections = NULL; abfd->section_count = 0; /* If this is the first dynamic object found in the link, create the special sections required for dynamic linking. */ if (! elf_hash_table (info)->dynamic_sections_created) { if (! elf_link_create_dynamic_sections (abfd, info)) goto error_return; } if (add_needed) { /* Add a DT_NEEDED entry for this dynamic object. */ oldsize = _bfd_stringtab_size (elf_hash_table (info)->dynstr); strindex = _bfd_stringtab_add (elf_hash_table (info)->dynstr, name, true, false); if (strindex == (bfd_size_type) -1) goto error_return; if (oldsize == _bfd_stringtab_size (elf_hash_table (info)->dynstr)) { asection *sdyn; Elf_External_Dyn *dyncon, *dynconend; /* The hash table size did not change, which means that the dynamic object name was already entered. If we have already included this dynamic object in the link, just ignore it. There is no reason to include a particular dynamic object more than once. */ sdyn = bfd_get_section_by_name (elf_hash_table (info)->dynobj, ".dynamic"); BFD_ASSERT (sdyn != NULL); dyncon = (Elf_External_Dyn *) sdyn->contents; dynconend = (Elf_External_Dyn *) (sdyn->contents + sdyn->_raw_size); for (; dyncon < dynconend; dyncon++) { Elf_Internal_Dyn dyn; elf_swap_dyn_in (elf_hash_table (info)->dynobj, dyncon, &dyn); if (dyn.d_tag == DT_NEEDED && dyn.d_un.d_val == strindex) { if (buf != NULL) free (buf); if (extversym != NULL) free (extversym); return true; } } } if (! elf_add_dynamic_entry (info, DT_NEEDED, strindex)) goto error_return; } /* Save the SONAME, if there is one, because sometimes the linker emulation code will need to know it. */ if (*name == '\0') name = basename (bfd_get_filename (abfd)); elf_dt_name (abfd) = name; } if (bfd_seek (abfd, hdr->sh_offset + extsymoff * sizeof (Elf_External_Sym), SEEK_SET) != 0 || (bfd_read ((PTR) buf, sizeof (Elf_External_Sym), extsymcount, abfd) != extsymcount * sizeof (Elf_External_Sym))) goto error_return; weaks = NULL; ever = extversym != NULL ? extversym + extsymoff : NULL; esymend = buf + extsymcount; for (esym = buf; esym < esymend; esym++, sym_hash++, ever = (ever != NULL ? ever + 1 : NULL)) { Elf_Internal_Sym sym; int bind; bfd_vma value; asection *sec; flagword flags; const char *name; struct elf_link_hash_entry *h; boolean definition; boolean size_change_ok, type_change_ok; boolean new_weakdef; unsigned int old_alignment; elf_swap_symbol_in (abfd, esym, &sym); flags = BSF_NO_FLAGS; sec = NULL; value = sym.st_value; *sym_hash = NULL; bind = ELF_ST_BIND (sym.st_info); if (bind == STB_LOCAL) { /* This should be impossible, since ELF requires that all global symbols follow all local symbols, and that sh_info point to the first global symbol. Unfortunatealy, Irix 5 screws this up. */ continue; } else if (bind == STB_GLOBAL) { if (sym.st_shndx != SHN_UNDEF && sym.st_shndx != SHN_COMMON) flags = BSF_GLOBAL; } else if (bind == STB_WEAK) flags = BSF_WEAK; else { /* Leave it up to the processor backend. */ } if (sym.st_shndx == SHN_UNDEF) sec = bfd_und_section_ptr; else if (sym.st_shndx > 0 && sym.st_shndx < SHN_LORESERVE) { sec = section_from_elf_index (abfd, sym.st_shndx); if (sec == NULL) sec = bfd_abs_section_ptr; else if ((abfd->flags & (EXEC_P | DYNAMIC)) != 0) value -= sec->vma; } else if (sym.st_shndx == SHN_ABS) sec = bfd_abs_section_ptr; else if (sym.st_shndx == SHN_COMMON) { sec = bfd_com_section_ptr; /* What ELF calls the size we call the value. What ELF calls the value we call the alignment. */ value = sym.st_size; } else { /* Leave it up to the processor backend. */ } name = bfd_elf_string_from_elf_section (abfd, hdr->sh_link, sym.st_name); if (name == (const char *) NULL) goto error_return; if (add_symbol_hook) { if (! (*add_symbol_hook) (abfd, info, &sym, &name, &flags, &sec, &value)) goto error_return; /* The hook function sets the name to NULL if this symbol should be skipped for some reason. */ if (name == (const char *) NULL) continue; } /* Sanity check that all possibilities were handled. */ if (sec == (asection *) NULL) { bfd_set_error (bfd_error_bad_value); goto error_return; } if (bfd_is_und_section (sec) || bfd_is_com_section (sec)) definition = false; else definition = true; size_change_ok = false; type_change_ok = get_elf_backend_data (abfd)->type_change_ok; old_alignment = 0; if (info->hash->creator->flavour == bfd_target_elf_flavour) { Elf_Internal_Versym iver; unsigned int vernum = 0; boolean override; if (ever != NULL) { _bfd_elf_swap_versym_in (abfd, ever, &iver); vernum = iver.vs_vers & VERSYM_VERSION; /* If this is a hidden symbol, or if it is not version 1, we append the version name to the symbol name. However, we do not modify a non-hidden absolute symbol, because it might be the version symbol itself. FIXME: What if it isn't? */ if ((iver.vs_vers & VERSYM_HIDDEN) != 0 || (vernum > 1 && ! bfd_is_abs_section (sec))) { const char *verstr; int namelen, newlen; char *newname, *p; if (sym.st_shndx != SHN_UNDEF) { if (vernum > elf_tdata (abfd)->dynverdef_hdr.sh_info) { (*_bfd_error_handler) (_("%s: %s: invalid version %u (max %d)"), bfd_get_filename (abfd), name, vernum, elf_tdata (abfd)->dynverdef_hdr.sh_info); bfd_set_error (bfd_error_bad_value); goto error_return; } else if (vernum > 1) verstr = elf_tdata (abfd)->verdef[vernum - 1].vd_nodename; else verstr = ""; } else { /* We cannot simply test for the number of entries in the VERNEED section since the numbers for the needed versions do not start at 0. */ Elf_Internal_Verneed *t; verstr = NULL; for (t = elf_tdata (abfd)->verref; t != NULL; t = t->vn_nextref) { Elf_Internal_Vernaux *a; for (a = t->vn_auxptr; a != NULL; a = a->vna_nextptr) { if (a->vna_other == vernum) { verstr = a->vna_nodename; break; } } if (a != NULL) break; } if (verstr == NULL) { (*_bfd_error_handler) (_("%s: %s: invalid needed version %d"), bfd_get_filename (abfd), name, vernum); bfd_set_error (bfd_error_bad_value); goto error_return; } } namelen = strlen (name); newlen = namelen + strlen (verstr) + 2; if ((iver.vs_vers & VERSYM_HIDDEN) == 0) ++newlen; newname = (char *) bfd_alloc (abfd, newlen); if (newname == NULL) goto error_return; strcpy (newname, name); p = newname + namelen; *p++ = ELF_VER_CHR; /* If this is a defined non-hidden version symbol, we add another @ to the name. This indicates the default version of the symbol. */ if ((iver.vs_vers & VERSYM_HIDDEN) == 0 && sym.st_shndx != SHN_UNDEF) *p++ = ELF_VER_CHR; strcpy (p, verstr); name = newname; } } if (! elf_merge_symbol (abfd, info, name, &sym, &sec, &value, sym_hash, &override, &type_change_ok, &size_change_ok, dt_needed)) goto error_return; if (override) definition = false; h = *sym_hash; 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; /* Remember the old alignment if this is a common symbol, so that we don't reduce the alignment later on. We can't check later, because _bfd_generic_link_add_one_symbol will set a default for the alignment which we want to override. */ if (h->root.type == bfd_link_hash_common) old_alignment = h->root.u.c.p->alignment_power; if (elf_tdata (abfd)->verdef != NULL && ! override && vernum > 1 && definition) h->verinfo.verdef = &elf_tdata (abfd)->verdef[vernum - 1]; } if (! (_bfd_generic_link_add_one_symbol (info, abfd, name, flags, sec, value, (const char *) NULL, false, collect, (struct bfd_link_hash_entry **) sym_hash))) goto error_return; h = *sym_hash; 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; *sym_hash = h; new_weakdef = false; if (dynamic && definition && (flags & BSF_WEAK) != 0 && ELF_ST_TYPE (sym.st_info) != STT_FUNC && info->hash->creator->flavour == bfd_target_elf_flavour && h->weakdef == NULL) { /* Keep a list of all weak defined non function symbols from a dynamic object, using the weakdef field. Later in this function we will set the weakdef field to the correct value. We only put non-function symbols from dynamic objects on this list, because that happens to be the only time we need to know the normal symbol corresponding to a weak symbol, and the information is time consuming to figure out. If the weakdef field is not already NULL, then this symbol was already defined by some previous dynamic object, and we will be using that previous definition anyhow. */ h->weakdef = weaks; weaks = h; new_weakdef = true; } /* Set the alignment of a common symbol. */ if (sym.st_shndx == SHN_COMMON && h->root.type == bfd_link_hash_common) { unsigned int align; align = bfd_log2 (sym.st_value); if (align > old_alignment /* Permit an alignment power of zero if an alignment of one is specified and no other alignments have been specified. */ || (sym.st_value == 1 && old_alignment == 0)) h->root.u.c.p->alignment_power = align; } if (info->hash->creator->flavour == bfd_target_elf_flavour) { int old_flags; boolean dynsym; int new_flag; /* Remember the symbol size and type. */ if (sym.st_size != 0 && (definition || h->size == 0)) { if (h->size != 0 && h->size != sym.st_size && ! size_change_ok) (*_bfd_error_handler) (_("Warning: size of symbol `%s' changed from %lu to %lu in %s"), name, (unsigned long) h->size, (unsigned long) sym.st_size, bfd_get_filename (abfd)); h->size = sym.st_size; } /* If this is a common symbol, then we always want H->SIZE to be the size of the common symbol. The code just above won't fix the size if a common symbol becomes larger. We don't warn about a size change here, because that is covered by --warn-common. */ if (h->root.type == bfd_link_hash_common) h->size = h->root.u.c.size; if (ELF_ST_TYPE (sym.st_info) != STT_NOTYPE && (definition || h->type == STT_NOTYPE)) { if (h->type != STT_NOTYPE && h->type != ELF_ST_TYPE (sym.st_info) && ! type_change_ok) (*_bfd_error_handler) (_("Warning: type of symbol `%s' changed from %d to %d in %s"), name, h->type, ELF_ST_TYPE (sym.st_info), bfd_get_filename (abfd)); h->type = ELF_ST_TYPE (sym.st_info); } /* If st_other has a processor-specific meaning, specific code might be needed here. */ if (sym.st_other != 0) { /* Combine visibilities, using the most constraining one. */ unsigned char hvis = ELF_ST_VISIBILITY (h->other); unsigned char symvis = ELF_ST_VISIBILITY (sym.st_other); if (symvis && (hvis > symvis || hvis == 0)) h->other = sym.st_other; /* If neither has visibility, use the st_other of the definition. This is an arbitrary choice, since the other bits have no general meaning. */ if (!symvis && !hvis && (definition || h->other == 0)) h->other = sym.st_other; } /* Set a flag in the hash table entry indicating the type of reference or definition we just found. Keep a count of the number of dynamic symbols we find. A dynamic symbol is one which is referenced or defined by both a regular object and a shared object. */ old_flags = h->elf_link_hash_flags; dynsym = false; if (! dynamic) { if (! definition) { new_flag = ELF_LINK_HASH_REF_REGULAR; if (bind != STB_WEAK) new_flag |= ELF_LINK_HASH_REF_REGULAR_NONWEAK; } else new_flag = ELF_LINK_HASH_DEF_REGULAR; if (info->shared || (old_flags & (ELF_LINK_HASH_DEF_DYNAMIC | ELF_LINK_HASH_REF_DYNAMIC)) != 0) dynsym = true; } else { if (! definition) new_flag = ELF_LINK_HASH_REF_DYNAMIC; else new_flag = ELF_LINK_HASH_DEF_DYNAMIC; if ((old_flags & (ELF_LINK_HASH_DEF_REGULAR | ELF_LINK_HASH_REF_REGULAR)) != 0 || (h->weakdef != NULL && ! new_weakdef && h->weakdef->dynindx != -1)) dynsym = true; } h->elf_link_hash_flags |= new_flag; /* 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. */ if (definition || h->root.type == bfd_link_hash_common) { char *p; p = strchr (name, ELF_VER_CHR); if (p != NULL && p[1] == ELF_VER_CHR) { char *shortname; struct elf_link_hash_entry *hi; boolean override; shortname = bfd_hash_allocate (&info->hash->table, p - name + 1); if (shortname == NULL) goto error_return; strncpy (shortname, name, p - name); shortname[p - name] = '\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; if (! elf_merge_symbol (abfd, info, shortname, &sym, &sec, &value, &hi, &override, &type_change_ok, &size_change_ok, dt_needed)) goto error_return; if (! override) { if (! (_bfd_generic_link_add_one_symbol (info, abfd, shortname, BSF_INDIRECT, bfd_ind_section_ptr, (bfd_vma) 0, name, false, collect, (struct bfd_link_hash_entry **) &hi))) goto error_return; } 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)) goto error_return; } } /* 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; /* If the symbol became indirect, then we assume that we have not seen a definition before. */ BFD_ASSERT ((hi->elf_link_hash_flags & (ELF_LINK_HASH_DEF_DYNAMIC | ELF_LINK_HASH_DEF_REGULAR)) == 0); ht = (struct elf_link_hash_entry *) hi->root.u.i.link; (*bed->elf_backend_copy_indirect_symbol) (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. */ shortname = bfd_hash_allocate (&info->hash->table, strlen (name)); if (shortname == NULL) goto error_return; strncpy (shortname, name, p - name); strcpy (shortname + (p - name), p + 1); /* Once again, merge with any existing symbol. */ type_change_ok = false; size_change_ok = false; if (! elf_merge_symbol (abfd, info, shortname, &sym, &sec, &value, &hi, &override, &type_change_ok, &size_change_ok, dt_needed)) goto error_return; 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. */ (*_bfd_error_handler) (_("%s: warning: unexpected redefinition of `%s'"), bfd_get_filename (abfd), shortname); } else { if (! (_bfd_generic_link_add_one_symbol (info, abfd, shortname, BSF_INDIRECT, bfd_ind_section_ptr, (bfd_vma) 0, name, false, collect, (struct bfd_link_hash_entry **) &hi))) goto error_return; /* 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) { /* If the symbol became indirect, then we assume that we have not seen a definition before. */ BFD_ASSERT ((hi->elf_link_hash_flags & (ELF_LINK_HASH_DEF_DYNAMIC | ELF_LINK_HASH_DEF_REGULAR)) == 0); (*bed->elf_backend_copy_indirect_symbol) (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; } } } } } } if (dynsym && h->dynindx == -1) { if (! _bfd_elf_link_record_dynamic_symbol (info, h)) goto error_return; if (h->weakdef != NULL && ! new_weakdef && h->weakdef->dynindx == -1) { if (! _bfd_elf_link_record_dynamic_symbol (info, h->weakdef)) goto error_return; } } else if (dynsym && h->dynindx != -1) /* If the symbol already has a dynamic index, but visibility says it should not be visible, turn it into a local symbol. */ switch (ELF_ST_VISIBILITY (h->other)) { case STV_INTERNAL: case STV_HIDDEN: h->elf_link_hash_flags |= ELF_LINK_FORCED_LOCAL; (*bed->elf_backend_hide_symbol) (info, h); break; } if (dt_needed && definition && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) != 0) { bfd_size_type oldsize; bfd_size_type strindex; /* The symbol from a DT_NEEDED object is referenced from the regular object to create a dynamic executable. We have to make sure there is a DT_NEEDED entry for it. */ dt_needed = false; oldsize = _bfd_stringtab_size (elf_hash_table (info)->dynstr); strindex = _bfd_stringtab_add (elf_hash_table (info)->dynstr, elf_dt_soname (abfd), true, false); if (strindex == (bfd_size_type) -1) goto error_return; if (oldsize == _bfd_stringtab_size (elf_hash_table (info)->dynstr)) { asection *sdyn; Elf_External_Dyn *dyncon, *dynconend; sdyn = bfd_get_section_by_name (elf_hash_table (info)->dynobj, ".dynamic"); BFD_ASSERT (sdyn != NULL); dyncon = (Elf_External_Dyn *) sdyn->contents; dynconend = (Elf_External_Dyn *) (sdyn->contents + sdyn->_raw_size); for (; dyncon < dynconend; dyncon++) { Elf_Internal_Dyn dyn; elf_swap_dyn_in (elf_hash_table (info)->dynobj, dyncon, &dyn); BFD_ASSERT (dyn.d_tag != DT_NEEDED || dyn.d_un.d_val != strindex); } } if (! elf_add_dynamic_entry (info, DT_NEEDED, strindex)) goto error_return; } } } /* Now set the weakdefs field correctly for all the weak defined symbols we found. The only way to do this is to search all the symbols. Since we only need the information for non functions in dynamic objects, that's the only time we actually put anything on the list WEAKS. We need this information so that if a regular object refers to a symbol defined weakly in a dynamic object, the real symbol in the dynamic object is also put in the dynamic symbols; we also must arrange for both symbols to point to the same memory location. We could handle the general case of symbol aliasing, but a general symbol alias can only be generated in assembler code, handling it correctly would be very time consuming, and other ELF linkers don't handle general aliasing either. */ while (weaks != NULL) { struct elf_link_hash_entry *hlook; asection *slook; bfd_vma vlook; struct elf_link_hash_entry **hpp; struct elf_link_hash_entry **hppend; hlook = weaks; weaks = hlook->weakdef; hlook->weakdef = NULL; BFD_ASSERT (hlook->root.type == bfd_link_hash_defined || hlook->root.type == bfd_link_hash_defweak || hlook->root.type == bfd_link_hash_common || hlook->root.type == bfd_link_hash_indirect); slook = hlook->root.u.def.section; vlook = hlook->root.u.def.value; hpp = elf_sym_hashes (abfd); hppend = hpp + extsymcount; for (; hpp < hppend; hpp++) { struct elf_link_hash_entry *h; h = *hpp; if (h != NULL && h != hlook && h->root.type == bfd_link_hash_defined && h->root.u.def.section == slook && h->root.u.def.value == vlook) { hlook->weakdef = h; /* If the weak definition is in the list of dynamic symbols, make sure the real definition is put there as well. */ if (hlook->dynindx != -1 && h->dynindx == -1) { if (! _bfd_elf_link_record_dynamic_symbol (info, h)) goto error_return; } /* If the real definition is in the list of dynamic symbols, make sure the weak definition is put there as well. If we don't do this, then the dynamic loader might not merge the entries for the real definition and the weak definition. */ if (h->dynindx != -1 && hlook->dynindx == -1) { if (! _bfd_elf_link_record_dynamic_symbol (info, hlook)) goto error_return; } break; } } } if (buf != NULL) { free (buf); buf = NULL; } if (extversym != NULL) { free (extversym); extversym = NULL; } /* If this object is the same format as the output object, and it is not a shared library, then let the backend look through the relocs. This is required to build global offset table entries and to arrange for dynamic relocs. It is not required for the particular common case of linking non PIC code, even when linking against shared libraries, but unfortunately there is no way of knowing whether an object file has been compiled PIC or not. Looking through the relocs is not particularly time consuming. The problem is that we must either (1) keep the relocs in memory, which causes the linker to require additional runtime memory or (2) read the relocs twice from the input file, which wastes time. This would be a good case for using mmap. I have no idea how to handle linking PIC code into a file of a different format. It probably can't be done. */ check_relocs = get_elf_backend_data (abfd)->check_relocs; if (! dynamic && abfd->xvec == info->hash->creator && check_relocs != NULL) { asection *o; for (o = abfd->sections; o != NULL; o = o->next) { Elf_Internal_Rela *internal_relocs; boolean ok; if ((o->flags & SEC_RELOC) == 0 || o->reloc_count == 0 || ((info->strip == strip_all || info->strip == strip_debugger) && (o->flags & SEC_DEBUGGING) != 0) || bfd_is_abs_section (o->output_section)) continue; internal_relocs = (NAME(_bfd_elf,link_read_relocs) (abfd, o, (PTR) NULL, (Elf_Internal_Rela *) NULL, info->keep_memory)); if (internal_relocs == NULL) goto error_return; ok = (*check_relocs) (abfd, info, o, internal_relocs); if (! info->keep_memory) free (internal_relocs); if (! ok) goto error_return; } } /* If this is a non-traditional, non-relocateable link, try to optimize the handling of the .stab/.stabstr sections. */ if (! dynamic && ! info->relocateable && ! info->traditional_format && info->hash->creator->flavour == bfd_target_elf_flavour && (info->strip != strip_all && info->strip != strip_debugger)) { asection *stab, *stabstr; stab = bfd_get_section_by_name (abfd, ".stab"); if (stab != NULL) { stabstr = bfd_get_section_by_name (abfd, ".stabstr"); if (stabstr != NULL) { struct bfd_elf_section_data *secdata; secdata = elf_section_data (stab); if (! _bfd_link_section_stabs (abfd, &elf_hash_table (info)->stab_info, stab, stabstr, &secdata->stab_info)) goto error_return; } } } if (! info->relocateable && ! dynamic) { asection *s; for (s = abfd->sections; s != NULL; s = s->next) if ((s->flags & SEC_MERGE) && ! _bfd_merge_section (abfd, &elf_hash_table (info)->merge_info, s, &elf_section_data (s)->merge_info)) goto error_return; } return true; error_return: if (buf != NULL) free (buf); if (dynbuf != NULL) free (dynbuf); if (extversym != NULL) free (extversym); return false; } /* 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. */ boolean elf_link_create_dynamic_sections (abfd, info) bfd *abfd; struct bfd_link_info *info; { flagword flags; register asection *s; struct elf_link_hash_entry *h; struct elf_backend_data *bed; 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->shared) { s = bfd_make_section (abfd, ".interp"); if (s == NULL || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)) return false; } /* 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, 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, 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, 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 = elf_stringtab_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, 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. */ h = NULL; if (! (_bfd_generic_link_add_one_symbol (info, abfd, "_DYNAMIC", BSF_GLOBAL, s, (bfd_vma) 0, (const char *) NULL, false, get_elf_backend_data (abfd)->collect, (struct bfd_link_hash_entry **) &h))) return false; h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR; h->type = STT_OBJECT; if (info->shared && ! _bfd_elf_link_record_dynamic_symbol (info, h)) return false; bed = get_elf_backend_data (abfd); s = bfd_make_section (abfd, ".hash"); if (s == NULL || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY) || ! bfd_set_section_alignment (abfd, 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; } /* Add an entry to the .dynamic table. */ boolean elf_add_dynamic_entry (info, tag, val) struct bfd_link_info *info; bfd_vma tag; bfd_vma val; { Elf_Internal_Dyn dyn; bfd *dynobj; asection *s; size_t newsize; bfd_byte *newcontents; dynobj = elf_hash_table (info)->dynobj; s = bfd_get_section_by_name (dynobj, ".dynamic"); BFD_ASSERT (s != NULL); newsize = s->_raw_size + sizeof (Elf_External_Dyn); newcontents = (bfd_byte *) bfd_realloc (s->contents, newsize); if (newcontents == NULL) return false; dyn.d_tag = tag; dyn.d_un.d_val = val; elf_swap_dyn_out (dynobj, &dyn, (Elf_External_Dyn *) (newcontents + s->_raw_size)); s->_raw_size = newsize; s->contents = newcontents; return true; } /* Record a new local dynamic symbol. */ boolean elf_link_record_local_dynamic_symbol (info, input_bfd, input_indx) struct bfd_link_info *info; bfd *input_bfd; long input_indx; { struct elf_link_local_dynamic_entry *entry; struct elf_link_hash_table *eht; struct bfd_strtab_hash *dynstr; Elf_External_Sym esym; unsigned long dynstr_index; char *name; /* 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 true; entry = (struct elf_link_local_dynamic_entry *) bfd_alloc (input_bfd, sizeof (*entry)); if (entry == NULL) return false; /* Go find the symbol, so that we can find it's name. */ if (bfd_seek (input_bfd, (elf_tdata (input_bfd)->symtab_hdr.sh_offset + input_indx * sizeof (Elf_External_Sym)), SEEK_SET) != 0 || (bfd_read (&esym, sizeof (Elf_External_Sym), 1, input_bfd) != sizeof (Elf_External_Sym))) return false; elf_swap_symbol_in (input_bfd, &esym, &entry->isym); 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_stringtab_init (); if (dynstr == NULL) return false; } dynstr_index = _bfd_stringtab_add (dynstr, name, true, false); if (dynstr_index == (unsigned long) -1) return false; 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 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 boolean elf_link_read_relocs_from_section (abfd, shdr, external_relocs, internal_relocs) bfd *abfd; Elf_Internal_Shdr *shdr; PTR external_relocs; Elf_Internal_Rela *internal_relocs; { struct elf_backend_data *bed; /* If there aren't any relocations, that's OK. */ if (!shdr) return true; /* 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_read (external_relocs, 1, shdr->sh_size, abfd) != shdr->sh_size) return false; bed = get_elf_backend_data (abfd); /* Convert the external relocations to the internal format. */ if (shdr->sh_entsize == sizeof (Elf_External_Rel)) { Elf_External_Rel *erel; Elf_External_Rel *erelend; Elf_Internal_Rela *irela; Elf_Internal_Rel *irel; erel = (Elf_External_Rel *) external_relocs; erelend = erel + NUM_SHDR_ENTRIES (shdr); irela = internal_relocs; irel = bfd_alloc (abfd, (bed->s->int_rels_per_ext_rel * sizeof (Elf_Internal_Rel))); for (; erel < erelend; erel++, irela += bed->s->int_rels_per_ext_rel) { unsigned int i; if (bed->s->swap_reloc_in) (*bed->s->swap_reloc_in) (abfd, (bfd_byte *) erel, irel); else elf_swap_reloc_in (abfd, erel, irel); for (i = 0; i < bed->s->int_rels_per_ext_rel; ++i) { irela[i].r_offset = irel[i].r_offset; irela[i].r_info = irel[i].r_info; irela[i].r_addend = 0; } } } else { Elf_External_Rela *erela; Elf_External_Rela *erelaend; Elf_Internal_Rela *irela; BFD_ASSERT (shdr->sh_entsize == sizeof (Elf_External_Rela)); erela = (Elf_External_Rela *) external_relocs; erelaend = erela + NUM_SHDR_ENTRIES (shdr); irela = internal_relocs; for (; erela < erelaend; erela++, irela += bed->s->int_rels_per_ext_rel) { if (bed->s->swap_reloca_in) (*bed->s->swap_reloca_in) (abfd, (bfd_byte *) erela, irela); else elf_swap_reloca_in (abfd, erela, irela); } } 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 * NAME(_bfd_elf,link_read_relocs) (abfd, o, external_relocs, internal_relocs, keep_memory) bfd *abfd; asection *o; PTR external_relocs; Elf_Internal_Rela *internal_relocs; boolean keep_memory; { Elf_Internal_Shdr *rel_hdr; PTR alloc1 = NULL; Elf_Internal_Rela *alloc2 = NULL; 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) { size_t size; size = (o->reloc_count * bed->s->int_rels_per_ext_rel * sizeof (Elf_Internal_Rela)); if (keep_memory) internal_relocs = (Elf_Internal_Rela *) bfd_alloc (abfd, size); else internal_relocs = alloc2 = (Elf_Internal_Rela *) bfd_malloc (size); if (internal_relocs == NULL) goto error_return; } if (external_relocs == NULL) { size_t size = (size_t) rel_hdr->sh_size; if (elf_section_data (o)->rel_hdr2) size += (size_t) elf_section_data (o)->rel_hdr2->sh_size; alloc1 = (PTR) bfd_malloc (size); if (alloc1 == NULL) goto error_return; external_relocs = alloc1; } if (!elf_link_read_relocs_from_section (abfd, rel_hdr, external_relocs, internal_relocs)) goto error_return; if (!elf_link_read_relocs_from_section (abfd, 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; } /* Record an assignment to a symbol made by a linker script. We need this in case some dynamic object refers to this symbol. */ /*ARGSUSED*/ boolean NAME(bfd_elf,record_link_assignment) (output_bfd, info, name, provide) bfd *output_bfd ATTRIBUTE_UNUSED; struct bfd_link_info *info; const char *name; boolean provide; { struct elf_link_hash_entry *h; if (info->hash->creator->flavour != bfd_target_elf_flavour) return true; h = elf_link_hash_lookup (elf_hash_table (info), name, true, true, false); if (h == NULL) return false; 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; /* When possible, keep the original type of the symbol */ if (h->type == STT_NOTYPE) h->type = STT_OBJECT; 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; } /* This structure is used to pass information to elf_link_assign_sym_version. */ struct elf_assign_sym_version_info { /* Output BFD. */ bfd *output_bfd; /* General link information. */ struct bfd_link_info *info; /* Version tree. */ struct bfd_elf_version_tree *verdefs; /* Whether we had a failure. */ boolean failed; }; /* This structure is used to pass information to elf_link_find_version_dependencies. */ struct elf_find_verdep_info { /* Output BFD. */ bfd *output_bfd; /* General link information. */ struct bfd_link_info *info; /* The number of dependencies. */ unsigned int vers; /* Whether we had a failure. */ boolean failed; }; /* Array used to determine the number of hash table buckets to use based on the number of symbols there are. If there are fewer than 3 symbols we use 1 bucket, fewer than 17 symbols we use 3 buckets, fewer than 37 we use 17 buckets, and so forth. We never use more than 32771 buckets. */ static const size_t elf_buckets[] = { 1, 3, 17, 37, 67, 97, 131, 197, 263, 521, 1031, 2053, 4099, 8209, 16411, 32771, 0 }; /* Compute bucket count for hashing table. We do not use a static set of possible tables sizes anymore. Instead we determine for all possible reasonable sizes of the table the outcome (i.e., the number of collisions etc) and choose the best solution. The weighting functions are not too simple to allow the table to grow without bounds. Instead one of the weighting factors is the size. Therefore the result is always a good payoff between few collisions (= short chain lengths) and table size. */ static size_t compute_bucket_count (info) struct bfd_link_info *info; { size_t dynsymcount = elf_hash_table (info)->dynsymcount; size_t best_size = 0; unsigned long int *hashcodes; unsigned long int *hashcodesp; unsigned long int i; /* Compute the hash values for all exported symbols. At the same time store the values in an array so that we could use them for optimizations. */ hashcodes = (unsigned long int *) bfd_malloc (dynsymcount * sizeof (unsigned long int)); if (hashcodes == NULL) return 0; hashcodesp = hashcodes; /* Put all hash values in HASHCODES. */ elf_link_hash_traverse (elf_hash_table (info), elf_collect_hash_codes, &hashcodesp); /* We have a problem here. The following code to optimize the table size requires an integer type with more the 32 bits. If BFD_HOST_U_64_BIT is set we know about such a type. */ #ifdef BFD_HOST_U_64_BIT if (info->optimize == true) { unsigned long int nsyms = hashcodesp - hashcodes; size_t minsize; size_t maxsize; BFD_HOST_U_64_BIT best_chlen = ~((BFD_HOST_U_64_BIT) 0); unsigned long int *counts ; /* Possible optimization parameters: if we have NSYMS symbols we say that the hashing table must at least have NSYMS/4 and at most 2*NSYMS buckets. */ minsize = nsyms / 4; if (minsize == 0) minsize = 1; best_size = maxsize = nsyms * 2; /* Create array where we count the collisions in. We must use bfd_malloc since the size could be large. */ counts = (unsigned long int *) bfd_malloc (maxsize * sizeof (unsigned long int)); if (counts == NULL) { free (hashcodes); return 0; } /* Compute the "optimal" size for the hash table. The criteria is a minimal chain length. The minor criteria is (of course) the size of the table. */ for (i = minsize; i < maxsize; ++i) { /* Walk through the array of hashcodes and count the collisions. */ BFD_HOST_U_64_BIT max; unsigned long int j; unsigned long int fact; memset (counts, '\0', i * sizeof (unsigned long int)); /* Determine how often each hash bucket is used. */ for (j = 0; j < nsyms; ++j) ++counts[hashcodes[j] % i]; /* For the weight function we need some information about the pagesize on the target. This is information need not be 100% accurate. Since this information is not available (so far) we define it here to a reasonable default value. If it is crucial to have a better value some day simply define this value. */ # ifndef BFD_TARGET_PAGESIZE # define BFD_TARGET_PAGESIZE (4096) # endif /* We in any case need 2 + NSYMS entries for the size values and the chains. */ max = (2 + nsyms) * (ARCH_SIZE / 8); # if 1 /* Variant 1: optimize for short chains. We add the squares of all the chain lengths (which favous many small chain over a few long chains). */ for (j = 0; j < i; ++j) max += counts[j] * counts[j]; /* This adds penalties for the overall size of the table. */ fact = i / (BFD_TARGET_PAGESIZE / (ARCH_SIZE / 8)) + 1; max *= fact * fact; # else /* Variant 2: Optimize a lot more for small table. Here we also add squares of the size but we also add penalties for empty slots (the +1 term). */ for (j = 0; j < i; ++j) max += (1 + counts[j]) * (1 + counts[j]); /* The overall size of the table is considered, but not as strong as in variant 1, where it is squared. */ fact = i / (BFD_TARGET_PAGESIZE / (ARCH_SIZE / 8)) + 1; max *= fact; # endif /* Compare with current best results. */ if (max < best_chlen) { best_chlen = max; best_size = i; } } free (counts); } else #endif /* defined (BFD_HOST_U_64_BIT) */ { /* This is the fallback solution if no 64bit type is available or if we are not supposed to spend much time on optimizations. We select the bucket count using a fixed set of numbers. */ for (i = 0; elf_buckets[i] != 0; i++) { best_size = elf_buckets[i]; if (dynsymcount < elf_buckets[i + 1]) break; } } /* Free the arrays we needed. */ free (hashcodes); return best_size; } /* Set up the sizes and contents of the ELF dynamic sections. This is called by the ELF linker emulation before_allocation routine. We must set the sizes of the sections before the linker sets the addresses of the various sections. */ boolean NAME(bfd_elf,size_dynamic_sections) (output_bfd, soname, rpath, filter_shlib, auxiliary_filters, info, sinterpptr, verdefs) bfd *output_bfd; const char *soname; const char *rpath; const char *filter_shlib; const char * const *auxiliary_filters; struct bfd_link_info *info; asection **sinterpptr; struct bfd_elf_version_tree *verdefs; { bfd_size_type soname_indx; bfd *dynobj; struct elf_backend_data *bed; struct elf_assign_sym_version_info asvinfo; *sinterpptr = NULL; soname_indx = (bfd_size_type) -1; if (info->hash->creator->flavour != bfd_target_elf_flavour) return true; /* The backend may have to create some sections regardless of whether we're dynamic or not. */ bed = get_elf_backend_data (output_bfd); if (bed->elf_backend_always_size_sections && ! (*bed->elf_backend_always_size_sections) (output_bfd, info)) return false; dynobj = elf_hash_table (info)->dynobj; /* If there were no dynamic objects in the link, there is nothing to do here. */ if (dynobj == NULL) return true; if (elf_hash_table (info)->dynamic_sections_created) { struct elf_info_failed eif; struct elf_link_hash_entry *h; asection *dynstr; *sinterpptr = bfd_get_section_by_name (dynobj, ".interp"); BFD_ASSERT (*sinterpptr != NULL || info->shared); if (soname != NULL) { soname_indx = _bfd_stringtab_add (elf_hash_table (info)->dynstr, soname, true, true); if (soname_indx == (bfd_size_type) -1 || ! elf_add_dynamic_entry (info, DT_SONAME, soname_indx)) return false; } if (info->symbolic) { if (! elf_add_dynamic_entry (info, DT_SYMBOLIC, 0)) return false; info->flags |= DF_SYMBOLIC; } if (rpath != NULL) { bfd_size_type indx; indx = _bfd_stringtab_add (elf_hash_table (info)->dynstr, rpath, true, true); if (indx == (bfd_size_type) -1 || ! elf_add_dynamic_entry (info, DT_RPATH, indx) || (info->new_dtags && ! elf_add_dynamic_entry (info, DT_RUNPATH, indx))) return false; } if (filter_shlib != NULL) { bfd_size_type indx; indx = _bfd_stringtab_add (elf_hash_table (info)->dynstr, filter_shlib, true, true); if (indx == (bfd_size_type) -1 || ! elf_add_dynamic_entry (info, DT_FILTER, indx)) return false; } if (auxiliary_filters != NULL) { const char * const *p; for (p = auxiliary_filters; *p != NULL; p++) { bfd_size_type indx; indx = _bfd_stringtab_add (elf_hash_table (info)->dynstr, *p, true, true); if (indx == (bfd_size_type) -1 || ! elf_add_dynamic_entry (info, DT_AUXILIARY, indx)) return false; } } eif.info = info; eif.verdefs = verdefs; eif.failed = false; /* If we are supposed to export all symbols into the dynamic symbol table (this is not the normal case), then do so. */ if (info->export_dynamic) { elf_link_hash_traverse (elf_hash_table (info), elf_export_symbol, (PTR) &eif); if (eif.failed) return false; } /* Attach all the symbols to their version information. */ asvinfo.output_bfd = output_bfd; asvinfo.info = info; asvinfo.verdefs = verdefs; asvinfo.failed = false; elf_link_hash_traverse (elf_hash_table (info), elf_link_assign_sym_version, (PTR) &asvinfo); if (asvinfo.failed) return false; /* Find all symbols which were defined in a dynamic object and make the backend pick a reasonable value for them. */ elf_link_hash_traverse (elf_hash_table (info), elf_adjust_dynamic_symbol, (PTR) &eif); if (eif.failed) return false; /* Add some entries to the .dynamic section. We fill in some of the values later, in elf_bfd_final_link, but we must add the entries now so that we know the final size of the .dynamic section. */ /* If there are initialization and/or finalization functions to call then add the corresponding DT_INIT/DT_FINI entries. */ h = (info->init_function ? elf_link_hash_lookup (elf_hash_table (info), info->init_function, false, false, false) : NULL); if (h != NULL && (h->elf_link_hash_flags & (ELF_LINK_HASH_REF_REGULAR | ELF_LINK_HASH_DEF_REGULAR)) != 0) { if (! elf_add_dynamic_entry (info, DT_INIT, 0)) return false; } h = (info->fini_function ? elf_link_hash_lookup (elf_hash_table (info), info->fini_function, false, false, false) : NULL); if (h != NULL && (h->elf_link_hash_flags & (ELF_LINK_HASH_REF_REGULAR | ELF_LINK_HASH_DEF_REGULAR)) != 0) { if (! elf_add_dynamic_entry (info, DT_FINI, 0)) return false; } dynstr = bfd_get_section_by_name (dynobj, ".dynstr"); /* If .dynstr is excluded from the link, we don't want any of these tags. Strictly, we should be checking each section individually; This quick check covers for the case where someone does a /DISCARD/ : { *(*) }. */ if (dynstr != NULL && dynstr->output_section != bfd_abs_section_ptr) { bfd_size_type strsize; strsize = _bfd_stringtab_size (elf_hash_table (info)->dynstr); if (! elf_add_dynamic_entry (info, DT_HASH, 0) || ! elf_add_dynamic_entry (info, DT_STRTAB, 0) || ! elf_add_dynamic_entry (info, DT_SYMTAB, 0) || ! elf_add_dynamic_entry (info, DT_STRSZ, strsize) || ! elf_add_dynamic_entry (info, DT_SYMENT, sizeof (Elf_External_Sym))) return false; } } /* The backend must work out the sizes of all the other dynamic sections. */ if (bed->elf_backend_size_dynamic_sections && ! (*bed->elf_backend_size_dynamic_sections) (output_bfd, info)) return false; if (elf_hash_table (info)->dynamic_sections_created) { size_t dynsymcount; asection *s; size_t bucketcount = 0; size_t hash_entry_size; /* Set up the version definition section. */ s = bfd_get_section_by_name (dynobj, ".gnu.version_d"); BFD_ASSERT (s != NULL); /* We may have created additional version definitions if we are just linking a regular application. */ verdefs = asvinfo.verdefs; if (verdefs == NULL) _bfd_strip_section_from_output (info, s); else { unsigned int cdefs; bfd_size_type size; struct bfd_elf_version_tree *t; bfd_byte *p; Elf_Internal_Verdef def; Elf_Internal_Verdaux defaux; cdefs = 0; size = 0; /* Make space for the base version. */ size += sizeof (Elf_External_Verdef); size += sizeof (Elf_External_Verdaux); ++cdefs; for (t = verdefs; t != NULL; t = t->next) { struct bfd_elf_version_deps *n; size += sizeof (Elf_External_Verdef); size += sizeof (Elf_External_Verdaux); ++cdefs; for (n = t->deps; n != NULL; n = n->next) size += sizeof (Elf_External_Verdaux); } s->_raw_size = size; s->contents = (bfd_byte *) bfd_alloc (output_bfd, s->_raw_size); if (s->contents == NULL && s->_raw_size != 0) return false; /* Fill in the version definition section. */ p = s->contents; def.vd_version = VER_DEF_CURRENT; def.vd_flags = VER_FLG_BASE; def.vd_ndx = 1; def.vd_cnt = 1; def.vd_aux = sizeof (Elf_External_Verdef); def.vd_next = (sizeof (Elf_External_Verdef) + sizeof (Elf_External_Verdaux)); if (soname_indx != (bfd_size_type) -1) { def.vd_hash = bfd_elf_hash (soname); defaux.vda_name = soname_indx; } else { const char *name; bfd_size_type indx; name = basename (output_bfd->filename); def.vd_hash = bfd_elf_hash (name); indx = _bfd_stringtab_add (elf_hash_table (info)->dynstr, name, true, false); if (indx == (bfd_size_type) -1) return false; defaux.vda_name = indx; } defaux.vda_next = 0; _bfd_elf_swap_verdef_out (output_bfd, &def, (Elf_External_Verdef *)p); p += sizeof (Elf_External_Verdef); _bfd_elf_swap_verdaux_out (output_bfd, &defaux, (Elf_External_Verdaux *) p); p += sizeof (Elf_External_Verdaux); for (t = verdefs; t != NULL; t = t->next) { unsigned int cdeps; struct bfd_elf_version_deps *n; struct elf_link_hash_entry *h; cdeps = 0; for (n = t->deps; n != NULL; n = n->next) ++cdeps; /* Add a symbol representing this version. */ h = NULL; if (! (_bfd_generic_link_add_one_symbol (info, dynobj, t->name, BSF_GLOBAL, bfd_abs_section_ptr, (bfd_vma) 0, (const char *) NULL, false, get_elf_backend_data (dynobj)->collect, (struct bfd_link_hash_entry **) &h))) return false; h->elf_link_hash_flags &= ~ ELF_LINK_NON_ELF; h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR; h->type = STT_OBJECT; h->verinfo.vertree = t; if (! _bfd_elf_link_record_dynamic_symbol (info, h)) return false; def.vd_version = VER_DEF_CURRENT; def.vd_flags = 0; if (t->globals == NULL && t->locals == NULL && ! t->used) def.vd_flags |= VER_FLG_WEAK; def.vd_ndx = t->vernum + 1; def.vd_cnt = cdeps + 1; def.vd_hash = bfd_elf_hash (t->name); def.vd_aux = sizeof (Elf_External_Verdef); if (t->next != NULL) def.vd_next = (sizeof (Elf_External_Verdef) + (cdeps + 1) * sizeof (Elf_External_Verdaux)); else def.vd_next = 0; _bfd_elf_swap_verdef_out (output_bfd, &def, (Elf_External_Verdef *) p); p += sizeof (Elf_External_Verdef); defaux.vda_name = h->dynstr_index; if (t->deps == NULL) defaux.vda_next = 0; else defaux.vda_next = sizeof (Elf_External_Verdaux); t->name_indx = defaux.vda_name; _bfd_elf_swap_verdaux_out (output_bfd, &defaux, (Elf_External_Verdaux *) p); p += sizeof (Elf_External_Verdaux); for (n = t->deps; n != NULL; n = n->next) { if (n->version_needed == NULL) { /* This can happen if there was an error in the version script. */ defaux.vda_name = 0; } else defaux.vda_name = n->version_needed->name_indx; if (n->next == NULL) defaux.vda_next = 0; else defaux.vda_next = sizeof (Elf_External_Verdaux); _bfd_elf_swap_verdaux_out (output_bfd, &defaux, (Elf_External_Verdaux *) p); p += sizeof (Elf_External_Verdaux); } } if (! elf_add_dynamic_entry (info, DT_VERDEF, 0) || ! elf_add_dynamic_entry (info, DT_VERDEFNUM, cdefs)) return false; elf_tdata (output_bfd)->cverdefs = cdefs; } if (info->new_dtags && info->flags) { if (! elf_add_dynamic_entry (info, DT_FLAGS, info->flags)) return false; } if (info->flags_1) { if (! info->shared) info->flags_1 &= ~ (DF_1_INITFIRST | DF_1_NODELETE | DF_1_NOOPEN); if (! elf_add_dynamic_entry (info, DT_FLAGS_1, info->flags_1)) return false; } /* Work out the size of the version reference section. */ s = bfd_get_section_by_name (dynobj, ".gnu.version_r"); BFD_ASSERT (s != NULL); { struct elf_find_verdep_info sinfo; sinfo.output_bfd = output_bfd; sinfo.info = info; sinfo.vers = elf_tdata (output_bfd)->cverdefs; if (sinfo.vers == 0) sinfo.vers = 1; sinfo.failed = false; elf_link_hash_traverse (elf_hash_table (info), elf_link_find_version_dependencies, (PTR) &sinfo); if (elf_tdata (output_bfd)->verref == NULL) _bfd_strip_section_from_output (info, s); else { Elf_Internal_Verneed *t; unsigned int size; unsigned int crefs; bfd_byte *p; /* Build the version definition section. */ size = 0; crefs = 0; for (t = elf_tdata (output_bfd)->verref; t != NULL; t = t->vn_nextref) { Elf_Internal_Vernaux *a; size += sizeof (Elf_External_Verneed); ++crefs; for (a = t->vn_auxptr; a != NULL; a = a->vna_nextptr) size += sizeof (Elf_External_Vernaux); } s->_raw_size = size; s->contents = (bfd_byte *) bfd_alloc (output_bfd, size); if (s->contents == NULL) return false; p = s->contents; for (t = elf_tdata (output_bfd)->verref; t != NULL; t = t->vn_nextref) { unsigned int caux; Elf_Internal_Vernaux *a; bfd_size_type indx; caux = 0; for (a = t->vn_auxptr; a != NULL; a = a->vna_nextptr) ++caux; t->vn_version = VER_NEED_CURRENT; t->vn_cnt = caux; if (elf_dt_name (t->vn_bfd) != NULL) indx = _bfd_stringtab_add (elf_hash_table (info)->dynstr, elf_dt_name (t->vn_bfd), true, false); else indx = _bfd_stringtab_add (elf_hash_table (info)->dynstr, basename (t->vn_bfd->filename), true, false); if (indx == (bfd_size_type) -1) return false; t->vn_file = indx; t->vn_aux = sizeof (Elf_External_Verneed); if (t->vn_nextref == NULL) t->vn_next = 0; else t->vn_next = (sizeof (Elf_External_Verneed) + caux * sizeof (Elf_External_Vernaux)); _bfd_elf_swap_verneed_out (output_bfd, t, (Elf_External_Verneed *) p); p += sizeof (Elf_External_Verneed); for (a = t->vn_auxptr; a != NULL; a = a->vna_nextptr) { a->vna_hash = bfd_elf_hash (a->vna_nodename); indx = _bfd_stringtab_add (elf_hash_table (info)->dynstr, a->vna_nodename, true, false); if (indx == (bfd_size_type) -1) return false; a->vna_name = indx; if (a->vna_nextptr == NULL) a->vna_next = 0; else a->vna_next = sizeof (Elf_External_Vernaux); _bfd_elf_swap_vernaux_out (output_bfd, a, (Elf_External_Vernaux *) p); p += sizeof (Elf_External_Vernaux); } } if (! elf_add_dynamic_entry (info, DT_VERNEED, 0) || ! elf_add_dynamic_entry (info, DT_VERNEEDNUM, crefs)) return false; elf_tdata (output_bfd)->cverrefs = crefs; } } /* Assign dynsym indicies. 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. */ dynsymcount = _bfd_elf_link_renumber_dynsyms (output_bfd, info); /* Work out the size of the symbol version section. */ s = bfd_get_section_by_name (dynobj, ".gnu.version"); BFD_ASSERT (s != NULL); if (dynsymcount == 0 || (verdefs == NULL && elf_tdata (output_bfd)->verref == NULL)) { _bfd_strip_section_from_output (info, s); /* The DYNSYMCOUNT might have changed if we were going to output a dynamic symbol table entry for S. */ dynsymcount = _bfd_elf_link_renumber_dynsyms (output_bfd, info); } else { s->_raw_size = dynsymcount * sizeof (Elf_External_Versym); s->contents = (bfd_byte *) bfd_zalloc (output_bfd, s->_raw_size); if (s->contents == NULL) return false; if (! elf_add_dynamic_entry (info, DT_VERSYM, 0)) return false; } /* Set the size of the .dynsym and .hash sections. We counted the number of dynamic symbols in elf_link_add_object_symbols. We will build the contents of .dynsym and .hash when we build the final symbol table, because until then we do not know the correct value to give the symbols. We built the .dynstr section as we went along in elf_link_add_object_symbols. */ s = bfd_get_section_by_name (dynobj, ".dynsym"); BFD_ASSERT (s != NULL); s->_raw_size = dynsymcount * sizeof (Elf_External_Sym); s->contents = (bfd_byte *) bfd_alloc (output_bfd, s->_raw_size); if (s->contents == NULL && s->_raw_size != 0) return false; if (dynsymcount != 0) { Elf_Internal_Sym isym; /* The first entry in .dynsym is a dummy symbol. */ isym.st_value = 0; isym.st_size = 0; isym.st_name = 0; isym.st_info = 0; isym.st_other = 0; isym.st_shndx = 0; elf_swap_symbol_out (output_bfd, &isym, (PTR) (Elf_External_Sym *) s->contents); } /* Compute the size of the hashing table. As a side effect this computes the hash values for all the names we export. */ bucketcount = compute_bucket_count (info); s = bfd_get_section_by_name (dynobj, ".hash"); BFD_ASSERT (s != NULL); hash_entry_size = elf_section_data (s)->this_hdr.sh_entsize; s->_raw_size = ((2 + bucketcount + dynsymcount) * hash_entry_size); s->contents = (bfd_byte *) bfd_alloc (output_bfd, s->_raw_size); if (s->contents == NULL) return false; memset (s->contents, 0, (size_t) s->_raw_size); bfd_put (8 * hash_entry_size, output_bfd, bucketcount, s->contents); bfd_put (8 * hash_entry_size, output_bfd, dynsymcount, s->contents + hash_entry_size); elf_hash_table (info)->bucketcount = bucketcount; s = bfd_get_section_by_name (dynobj, ".dynstr"); BFD_ASSERT (s != NULL); s->_raw_size = _bfd_stringtab_size (elf_hash_table (info)->dynstr); if (! elf_add_dynamic_entry (info, DT_NULL, 0)) return false; } 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. */ static boolean elf_fix_symbol_flags (h, eif) 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, and we can accomplish that by forcing it local. Likewise, if the symbol has hidden or internal visibility. FIXME: It might be that we also do not need a PLT for other non-hidden visibilities, but we would have to tell that to the backend specifically; we can't just clear PLT-related data here. */ if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) != 0 && eif->info->shared && (eif->info->symbolic || ELF_ST_VISIBILITY (h->other) == STV_INTERNAL || ELF_ST_VISIBILITY (h->other) == STV_HIDDEN) && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0) { struct elf_backend_data *bed; bed = get_elf_backend_data (elf_hash_table (eif->info)->dynobj); if (ELF_ST_VISIBILITY (h->other) == STV_INTERNAL || ELF_ST_VISIBILITY (h->other) == STV_HIDDEN) h->elf_link_hash_flags |= ELF_LINK_FORCED_LOCAL; (*bed->elf_backend_hide_symbol) (eif->info, h); } /* 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; BFD_ASSERT (h->root.type == bfd_link_hash_defined || h->root.type == bfd_link_hash_defweak); weakdef = h->weakdef; 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 elf_adjust_dynamic_symbol, below. */ if ((weakdef->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0) h->weakdef = NULL; else weakdef->elf_link_hash_flags |= (h->elf_link_hash_flags & (ELF_LINK_HASH_REF_REGULAR | ELF_LINK_HASH_REF_REGULAR_NONWEAK | ELF_LINK_NON_GOT_REF)); } 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. */ static boolean elf_adjust_dynamic_symbol (h, data) struct elf_link_hash_entry *h; PTR data; { struct elf_info_failed *eif = (struct elf_info_failed *) data; bfd *dynobj; struct elf_backend_data *bed; /* 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 (! 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.offset = (bfd_vma) -1; 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 (! elf_adjust_dynamic_symbol (h->weakdef, (PTR) 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; } /* This routine is used to export all defined symbols into the dynamic symbol table. It is called via elf_link_hash_traverse. */ static boolean elf_export_symbol (h, data) struct elf_link_hash_entry *h; PTR data; { struct elf_info_failed *eif = (struct elf_info_failed *) data; /* Ignore indirect symbols. These are added by the versioning code. */ if (h->root.type == bfd_link_hash_indirect) return true; 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 != NULL) { for (d = t->globals; d != NULL; d = d->next) { if ((*d->match) (d, h->root.root.string)) goto doit; } } if (t->locals != NULL) { for (d = t->locals ; d != NULL; d = d->next) { if ((*d->match) (d, h->root.root.string)) 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. */ static boolean elf_link_find_version_dependencies (h, data) struct elf_link_hash_entry *h; PTR data; { struct elf_find_verdep_info *rinfo = (struct elf_find_verdep_info *) data; Elf_Internal_Verneed *t; Elf_Internal_Vernaux *a; /* 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) { t = (Elf_Internal_Verneed *) bfd_zalloc (rinfo->output_bfd, sizeof *t); 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; } a = (Elf_Internal_Vernaux *) bfd_zalloc (rinfo->output_bfd, sizeof *a); /* 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. */ static boolean elf_link_assign_sym_version (h, data) struct elf_link_hash_entry *h; PTR data; { struct elf_assign_sym_version_info *sinfo = (struct elf_assign_sym_version_info *) data; struct bfd_link_info *info = sinfo->info; struct elf_backend_data *bed; struct elf_info_failed eif; char *p; /* Fix the symbol flags. */ eif.failed = false; eif.info = info; if (! 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; 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) { int len; char *alc; struct bfd_elf_version_expr *d; len = p - h->root.root.string; alc = bfd_alloc (sinfo->output_bfd, len); if (alc == NULL) return false; strncpy (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 != NULL) { for (d = t->globals; d != NULL; d = d->next) if ((*d->match) (d, alc)) break; } /* See if there is anything to force this symbol to local scope. */ if (d == NULL && t->locals != NULL) { for (d = t->locals; d != NULL; d = d->next) { if ((*d->match) (d, alc)) { if (h->dynindx != -1 && info->shared && ! info->export_dynamic) { h->elf_link_hash_flags |= ELF_LINK_FORCED_LOCAL; (*bed->elf_backend_hide_symbol) (info, h); /* FIXME: The name of the symbol has already been recorded in the dynamic string table section. */ } break; } } } bfd_release (sinfo->output_bfd, alc); break; } } /* If we are building an application, we need to create a version node for this version. */ if (t == NULL && ! info->shared) { 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; t = ((struct bfd_elf_version_tree *) bfd_alloc (sinfo->output_bfd, sizeof *t)); if (t == NULL) { sinfo->failed = true; return false; } t->next = NULL; t->name = p; t->globals = NULL; t->locals = NULL; t->deps = NULL; t->name_indx = (unsigned int) -1; t->used = true; version_index = 1; 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 *deflt; 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. */ deflt = NULL; for (t = sinfo->verdefs; t != NULL; t = t->next) { if (t->globals != NULL) { for (d = t->globals; d != NULL; d = d->next) { if ((*d->match) (d, h->root.root.string)) { h->verinfo.vertree = t; break; } } if (d != NULL) break; } if (t->locals != NULL) { for (d = t->locals; d != NULL; d = d->next) { if (d->pattern[0] == '*' && d->pattern[1] == '\0') deflt = t; else if ((*d->match) (d, h->root.root.string)) { h->verinfo.vertree = t; if (h->dynindx != -1 && info->shared && ! info->export_dynamic) { h->elf_link_hash_flags |= ELF_LINK_FORCED_LOCAL; (*bed->elf_backend_hide_symbol) (info, h); /* FIXME: The name of the symbol has already been recorded in the dynamic string table section. */ } break; } } if (d != NULL) break; } } if (deflt != NULL && h->verinfo.vertree == NULL) { h->verinfo.vertree = deflt; if (h->dynindx != -1 && info->shared && ! info->export_dynamic) { h->elf_link_hash_flags |= ELF_LINK_FORCED_LOCAL; (*bed->elf_backend_hide_symbol) (info, h); /* FIXME: The name of the symbol has already been recorded in the dynamic string table section. */ } } } return true; } /* Final phase of ELF linker. */ /* A structure we use to avoid passing large numbers of arguments. */ struct elf_final_link_info { /* General link information. */ struct bfd_link_info *info; /* Output BFD. */ bfd *output_bfd; /* Symbol string table. */ struct bfd_strtab_hash *symstrtab; /* .dynsym section. */ asection *dynsym_sec; /* .hash section. */ asection *hash_sec; /* symbol version section (.gnu.version). */ asection *symver_sec; /* Buffer large enough to hold contents of any section. */ bfd_byte *contents; /* Buffer large enough to hold external relocs of any section. */ PTR external_relocs; /* Buffer large enough to hold internal relocs of any section. */ Elf_Internal_Rela *internal_relocs; /* Buffer large enough to hold external local symbols of any input BFD. */ Elf_External_Sym *external_syms; /* Buffer large enough to hold internal local symbols of any input BFD. */ Elf_Internal_Sym *internal_syms; /* Array large enough to hold a symbol index for each local symbol of any input BFD. */ long *indices; /* Array large enough to hold a section pointer for each local symbol of any input BFD. */ asection **sections; /* Buffer to hold swapped out symbols. */ Elf_External_Sym *symbuf; /* Number of swapped out symbols in buffer. */ size_t symbuf_count; /* Number of symbols which fit in symbuf. */ size_t symbuf_size; }; static boolean elf_link_output_sym PARAMS ((struct elf_final_link_info *, const char *, Elf_Internal_Sym *, asection *)); static boolean elf_link_flush_output_syms PARAMS ((struct elf_final_link_info *)); static boolean elf_link_output_extsym PARAMS ((struct elf_link_hash_entry *, PTR)); static boolean elf_link_sec_merge_syms PARAMS ((struct elf_link_hash_entry *, PTR)); static boolean elf_link_input_bfd PARAMS ((struct elf_final_link_info *, bfd *)); static boolean elf_reloc_link_order PARAMS ((bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *)); /* This struct is used to pass information to elf_link_output_extsym. */ struct elf_outext_info { boolean failed; boolean localsyms; struct elf_final_link_info *finfo; }; /* Compute the size of, and allocate space for, REL_HDR which is the section header for a section containing relocations for O. */ static boolean elf_link_size_reloc_section (abfd, rel_hdr, o) bfd *abfd; Elf_Internal_Shdr *rel_hdr; asection *o; { unsigned reloc_count; unsigned 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 = (PTR) 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 = ((struct elf_link_hash_entry **) 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; } /* When performing a relocateable link, the input relocations are preserved. But, if they reference global symbols, the indices referenced must be updated. Update all the relocations in REL_HDR (there are COUNT of them), using the data in REL_HASH. */ static void elf_link_adjust_relocs (abfd, rel_hdr, count, rel_hash) bfd *abfd; Elf_Internal_Shdr *rel_hdr; unsigned int count; struct elf_link_hash_entry **rel_hash; { unsigned int i; struct elf_backend_data *bed = get_elf_backend_data (abfd); Elf_Internal_Rel *irel; Elf_Internal_Rela *irela; irel = (Elf_Internal_Rel *) bfd_zmalloc (sizeof (Elf_Internal_Rel) * bed->s->int_rels_per_ext_rel); if (irel == NULL) { (*_bfd_error_handler) (_("Error: out of memory")); abort (); } irela = (Elf_Internal_Rela *) bfd_zmalloc (sizeof (Elf_Internal_Rela) * bed->s->int_rels_per_ext_rel); if (irela == NULL) { (*_bfd_error_handler) (_("Error: out of memory")); abort (); } for (i = 0; i < count; i++, rel_hash++) { if (*rel_hash == NULL) continue; BFD_ASSERT ((*rel_hash)->indx >= 0); if (rel_hdr->sh_entsize == sizeof (Elf_External_Rel)) { Elf_External_Rel *erel; unsigned int j; erel = (Elf_External_Rel *) rel_hdr->contents + i; if (bed->s->swap_reloc_in) (*bed->s->swap_reloc_in) (abfd, (bfd_byte *) erel, irel); else elf_swap_reloc_in (abfd, erel, irel); for (j = 0; j < bed->s->int_rels_per_ext_rel; j++) irel[j].r_info = ELF_R_INFO ((*rel_hash)->indx, ELF_R_TYPE (irel[j].r_info)); if (bed->s->swap_reloc_out) (*bed->s->swap_reloc_out) (abfd, irel, (bfd_byte *) erel); else elf_swap_reloc_out (abfd, irel, erel); } else { Elf_External_Rela *erela; unsigned int j; BFD_ASSERT (rel_hdr->sh_entsize == sizeof (Elf_External_Rela)); erela = (Elf_External_Rela *) rel_hdr->contents + i; if (bed->s->swap_reloca_in) (*bed->s->swap_reloca_in) (abfd, (bfd_byte *) erela, irela); else elf_swap_reloca_in (abfd, erela, irela); for (j = 0; j < bed->s->int_rels_per_ext_rel; j++) irela[j].r_info = ELF_R_INFO ((*rel_hash)->indx, ELF_R_TYPE (irela[j].r_info)); if (bed->s->swap_reloca_out) (*bed->s->swap_reloca_out) (abfd, irela, (bfd_byte *) erela); else elf_swap_reloca_out (abfd, irela, erela); } } free (irel); free (irela); } /* Do the final step of an ELF link. */ boolean elf_bfd_final_link (abfd, info) bfd *abfd; struct bfd_link_info *info; { boolean dynamic; boolean emit_relocs; bfd *dynobj; struct elf_final_link_info finfo; register asection *o; register struct bfd_link_order *p; register bfd *sub; size_t max_contents_size; size_t max_external_reloc_size; size_t max_internal_reloc_count; size_t max_sym_count; file_ptr off; Elf_Internal_Sym elfsym; unsigned int i; Elf_Internal_Shdr *symtab_hdr; Elf_Internal_Shdr *symstrtab_hdr; struct elf_backend_data *bed = get_elf_backend_data (abfd); struct elf_outext_info eoinfo; boolean merged; if (info->shared) abfd->flags |= DYNAMIC; dynamic = elf_hash_table (info)->dynamic_sections_created; dynobj = elf_hash_table (info)->dynobj; emit_relocs = (info->relocateable || info->emitrelocations || bed->elf_backend_emit_relocs); finfo.info = info; finfo.output_bfd = abfd; finfo.symstrtab = elf_stringtab_init (); if (finfo.symstrtab == NULL) return false; if (! dynamic) { finfo.dynsym_sec = NULL; finfo.hash_sec = NULL; finfo.symver_sec = NULL; } else { finfo.dynsym_sec = bfd_get_section_by_name (dynobj, ".dynsym"); finfo.hash_sec = bfd_get_section_by_name (dynobj, ".hash"); BFD_ASSERT (finfo.dynsym_sec != NULL && finfo.hash_sec != NULL); finfo.symver_sec = bfd_get_section_by_name (dynobj, ".gnu.version"); /* Note that it is OK if symver_sec is NULL. */ } finfo.contents = NULL; finfo.external_relocs = NULL; finfo.internal_relocs = NULL; finfo.external_syms = NULL; finfo.internal_syms = NULL; finfo.indices = NULL; finfo.sections = NULL; finfo.symbuf = NULL; finfo.symbuf_count = 0; /* Count up the number of relocations we will output for each output section, so that we know the sizes of the reloc sections. We also figure out some maximum sizes. */ max_contents_size = 0; max_external_reloc_size = 0; max_internal_reloc_count = 0; max_sym_count = 0; merged = false; for (o = abfd->sections; o != (asection *) NULL; o = o->next) { o->reloc_count = 0; for (p = o->link_order_head; p != NULL; p = p->next) { if (p->type == bfd_section_reloc_link_order || p->type == bfd_symbol_reloc_link_order) ++o->reloc_count; else if (p->type == bfd_indirect_link_order) { asection *sec; sec = p->u.indirect.section; /* Mark all sections which are to be included in the link. This will normally be every section. We need to do this so that we can identify any sections which the linker has decided to not include. */ sec->linker_mark = true; if (sec->flags & SEC_MERGE) merged = true; if (info->relocateable || info->emitrelocations) o->reloc_count += sec->reloc_count; else if (bed->elf_backend_count_relocs) { Elf_Internal_Rela * relocs; relocs = (NAME(_bfd_elf,link_read_relocs) (abfd, sec, (PTR) NULL, (Elf_Internal_Rela *) NULL, info->keep_memory)); o->reloc_count += (*bed->elf_backend_count_relocs) (sec, relocs); if (!info->keep_memory) free (relocs); } if (sec->_raw_size > max_contents_size) max_contents_size = sec->_raw_size; if (sec->_cooked_size > max_contents_size) max_contents_size = sec->_cooked_size; /* We are interested in just local symbols, not all symbols. */ if (bfd_get_flavour (sec->owner) == bfd_target_elf_flavour && (sec->owner->flags & DYNAMIC) == 0) { size_t sym_count; if (elf_bad_symtab (sec->owner)) sym_count = (elf_tdata (sec->owner)->symtab_hdr.sh_size / sizeof (Elf_External_Sym)); else sym_count = elf_tdata (sec->owner)->symtab_hdr.sh_info; if (sym_count > max_sym_count) max_sym_count = sym_count; if ((sec->flags & SEC_RELOC) != 0) { size_t ext_size; ext_size = elf_section_data (sec)->rel_hdr.sh_size; if (ext_size > max_external_reloc_size) max_external_reloc_size = ext_size; if (sec->reloc_count > max_internal_reloc_count) max_internal_reloc_count = sec->reloc_count; } } } } if (o->reloc_count > 0) o->flags |= SEC_RELOC; else { /* Explicitly clear the SEC_RELOC flag. The linker tends to set it (this is probably a bug) and if it is set assign_section_numbers will create a reloc section. */ o->flags &=~ SEC_RELOC; } /* If the SEC_ALLOC flag is not set, force the section VMA to zero. This is done in elf_fake_sections as well, but forcing the VMA to 0 here will ensure that relocs against these sections are handled correctly. */ if ((o->flags & SEC_ALLOC) == 0 && ! o->user_set_vma) o->vma = 0; } if (! info->relocateable && merged) elf_link_hash_traverse (elf_hash_table (info), elf_link_sec_merge_syms, (PTR) abfd); /* Figure out the file positions for everything but the symbol table and the relocs. We set symcount to force assign_section_numbers to create a symbol table. */ bfd_get_symcount (abfd) = info->strip == strip_all ? 0 : 1; BFD_ASSERT (! abfd->output_has_begun); if (! _bfd_elf_compute_section_file_positions (abfd, info)) goto error_return; /* Figure out how many relocations we will have in each section. Just using RELOC_COUNT isn't good enough since that doesn't maintain a separate value for REL vs. RELA relocations. */ if (emit_relocs) for (sub = info->input_bfds; sub != NULL; sub = sub->link_next) for (o = sub->sections; o != NULL; o = o->next) { asection *output_section; if (! o->linker_mark) { /* This section was omitted from the link. */ continue; } output_section = o->output_section; if (output_section != NULL && (o->flags & SEC_RELOC) != 0) { struct bfd_elf_section_data *esdi = elf_section_data (o); struct bfd_elf_section_data *esdo = elf_section_data (output_section); unsigned int *rel_count; unsigned int *rel_count2; /* We must be careful to add the relocation froms the input section to the right output count. */ if (esdi->rel_hdr.sh_entsize == esdo->rel_hdr.sh_entsize) { rel_count = &esdo->rel_count; rel_count2 = &esdo->rel_count2; } else { rel_count = &esdo->rel_count2; rel_count2 = &esdo->rel_count; } *rel_count += NUM_SHDR_ENTRIES (& esdi->rel_hdr); if (esdi->rel_hdr2) *rel_count2 += NUM_SHDR_ENTRIES (esdi->rel_hdr2); output_section->flags |= SEC_RELOC; } } /* That created the reloc sections. Set their sizes, and assign them file positions, and allocate some buffers. */ for (o = abfd->sections; o != NULL; o = o->next) { if ((o->flags & SEC_RELOC) != 0) { if (!elf_link_size_reloc_section (abfd, &elf_section_data (o)->rel_hdr, o)) goto error_return; if (elf_section_data (o)->rel_hdr2 && !elf_link_size_reloc_section (abfd, elf_section_data (o)->rel_hdr2, o)) goto error_return; } /* Now, reset REL_COUNT and REL_COUNT2 so that we can use them to count upwards while actually outputting the relocations. */ elf_section_data (o)->rel_count = 0; elf_section_data (o)->rel_count2 = 0; } _bfd_elf_assign_file_positions_for_relocs (abfd); /* We have now assigned file positions for all the sections except .symtab and .strtab. We start the .symtab section at the current file position, and write directly to it. We build the .strtab section in memory. */ bfd_get_symcount (abfd) = 0; symtab_hdr = &elf_tdata (abfd)->symtab_hdr; /* sh_name is set in prep_headers. */ symtab_hdr->sh_type = SHT_SYMTAB; symtab_hdr->sh_flags = 0; symtab_hdr->sh_addr = 0; symtab_hdr->sh_size = 0; symtab_hdr->sh_entsize = sizeof (Elf_External_Sym); /* sh_link is set in assign_section_numbers. */ /* sh_info is set below. */ /* sh_offset is set just below. */ symtab_hdr->sh_addralign = bed->s->file_align; off = elf_tdata (abfd)->next_file_pos; off = _bfd_elf_assign_file_position_for_section (symtab_hdr, off, true); /* Note that at this point elf_tdata (abfd)->next_file_pos is incorrect. We do not yet know the size of the .symtab section. We correct next_file_pos below, after we do know the size. */ /* Allocate a buffer to hold swapped out symbols. This is to avoid continuously seeking to the right position in the file. */ if (! info->keep_memory || max_sym_count < 20) finfo.symbuf_size = 20; else finfo.symbuf_size = max_sym_count; finfo.symbuf = ((Elf_External_Sym *) bfd_malloc (finfo.symbuf_size * sizeof (Elf_External_Sym))); if (finfo.symbuf == NULL) goto error_return; /* Start writing out the symbol table. The first symbol is always a dummy symbol. */ if (info->strip != strip_all || emit_relocs) { elfsym.st_value = 0; elfsym.st_size = 0; elfsym.st_info = 0; elfsym.st_other = 0; elfsym.st_shndx = SHN_UNDEF; if (! elf_link_output_sym (&finfo, (const char *) NULL, &elfsym, bfd_und_section_ptr)) goto error_return; } #if 0 /* Some standard ELF linkers do this, but we don't because it causes bootstrap comparison failures. */ /* Output a file symbol for the output file as the second symbol. We output this even if we are discarding local symbols, although I'm not sure if this is correct. */ elfsym.st_value = 0; elfsym.st_size = 0; elfsym.st_info = ELF_ST_INFO (STB_LOCAL, STT_FILE); elfsym.st_other = 0; elfsym.st_shndx = SHN_ABS; if (! elf_link_output_sym (&finfo, bfd_get_filename (abfd), &elfsym, bfd_abs_section_ptr)) goto error_return; #endif /* Output a symbol for each section. We output these even if we are discarding local symbols, since they are used for relocs. These symbols have no names. We store the index of each one in the index field of the section, so that we can find it again when outputting relocs. */ if (info->strip != strip_all || emit_relocs) { elfsym.st_size = 0; elfsym.st_info = ELF_ST_INFO (STB_LOCAL, STT_SECTION); elfsym.st_other = 0; for (i = 1; i < elf_elfheader (abfd)->e_shnum; i++) { o = section_from_elf_index (abfd, i); if (o != NULL) o->target_index = bfd_get_symcount (abfd); elfsym.st_shndx = i; if (info->relocateable || o == NULL) elfsym.st_value = 0; else elfsym.st_value = o->vma; if (! elf_link_output_sym (&finfo, (const char *) NULL, &elfsym, o)) goto error_return; } } /* Allocate some memory to hold information read in from the input files. */ finfo.contents = (bfd_byte *) bfd_malloc (max_contents_size); finfo.external_relocs = (PTR) bfd_malloc (max_external_reloc_size); finfo.internal_relocs = ((Elf_Internal_Rela *) bfd_malloc (max_internal_reloc_count * sizeof (Elf_Internal_Rela) * bed->s->int_rels_per_ext_rel)); finfo.external_syms = ((Elf_External_Sym *) bfd_malloc (max_sym_count * sizeof (Elf_External_Sym))); finfo.internal_syms = ((Elf_Internal_Sym *) bfd_malloc (max_sym_count * sizeof (Elf_Internal_Sym))); finfo.indices = (long *) bfd_malloc (max_sym_count * sizeof (long)); finfo.sections = ((asection **) bfd_malloc (max_sym_count * sizeof (asection *))); if ((finfo.contents == NULL && max_contents_size != 0) || (finfo.external_relocs == NULL && max_external_reloc_size != 0) || (finfo.internal_relocs == NULL && max_internal_reloc_count != 0) || (finfo.external_syms == NULL && max_sym_count != 0) || (finfo.internal_syms == NULL && max_sym_count != 0) || (finfo.indices == NULL && max_sym_count != 0) || (finfo.sections == NULL && max_sym_count != 0)) goto error_return; /* Since ELF permits relocations to be against local symbols, we must have the local symbols available when we do the relocations. Since we would rather only read the local symbols once, and we would rather not keep them in memory, we handle all the relocations for a single input file at the same time. Unfortunately, there is no way to know the total number of local symbols until we have seen all of them, and the local symbol indices precede the global symbol indices. This means that when we are generating relocateable output, and we see a reloc against a global symbol, we can not know the symbol index until we have finished examining all the local symbols to see which ones we are going to output. To deal with this, we keep the relocations in memory, and don't output them until the end of the link. This is an unfortunate waste of memory, but I don't see a good way around it. Fortunately, it only happens when performing a relocateable link, which is not the common case. FIXME: If keep_memory is set we could write the relocs out and then read them again; I don't know how bad the memory loss will be. */ for (sub = info->input_bfds; sub != NULL; sub = sub->link_next) sub->output_has_begun = false; for (o = abfd->sections; o != NULL; o = o->next) { for (p = o->link_order_head; p != NULL; p = p->next) { if (p->type == bfd_indirect_link_order && (bfd_get_flavour (p->u.indirect.section->owner) == bfd_target_elf_flavour)) { sub = p->u.indirect.section->owner; if (! sub->output_has_begun) { if (! elf_link_input_bfd (&finfo, sub)) goto error_return; sub->output_has_begun = true; } } else if (p->type == bfd_section_reloc_link_order || p->type == bfd_symbol_reloc_link_order) { if (! elf_reloc_link_order (abfd, info, o, p)) goto error_return; } else { if (! _bfd_default_link_order (abfd, info, o, p)) goto error_return; } } } /* That wrote out all the local symbols. Finish up the symbol table with the global symbols. Even if we want to strip everything we can, we still need to deal with those global symbols that got converted to local in a version script. */ if (info->shared) { /* Output any global symbols that got converted to local in a version script. We do this in a separate step since ELF requires all local symbols to appear prior to any global symbols. FIXME: We should only do this if some global symbols were, in fact, converted to become local. FIXME: Will this work correctly with the Irix 5 linker? */ eoinfo.failed = false; eoinfo.finfo = &finfo; eoinfo.localsyms = true; elf_link_hash_traverse (elf_hash_table (info), elf_link_output_extsym, (PTR) &eoinfo); if (eoinfo.failed) return false; } /* The sh_info field records the index of the first non local symbol. */ symtab_hdr->sh_info = bfd_get_symcount (abfd); if (dynamic && finfo.dynsym_sec->output_section != bfd_abs_section_ptr) { Elf_Internal_Sym sym; Elf_External_Sym *dynsym = (Elf_External_Sym *)finfo.dynsym_sec->contents; long last_local = 0; /* Write out the section symbols for the output sections. */ if (info->shared) { asection *s; sym.st_size = 0; sym.st_name = 0; sym.st_info = ELF_ST_INFO (STB_LOCAL, STT_SECTION); sym.st_other = 0; for (s = abfd->sections; s != NULL; s = s->next) { int indx; indx = elf_section_data (s)->this_idx; BFD_ASSERT (indx > 0); sym.st_shndx = indx; sym.st_value = s->vma; elf_swap_symbol_out (abfd, &sym, dynsym + elf_section_data (s)->dynindx); } last_local = bfd_count_sections (abfd); } /* Write out the local dynsyms. */ if (elf_hash_table (info)->dynlocal) { struct elf_link_local_dynamic_entry *e; for (e = elf_hash_table (info)->dynlocal; e ; e = e->next) { asection *s; sym.st_size = e->isym.st_size; sym.st_other = e->isym.st_other; /* Copy the internal symbol as is. Note that we saved a word of storage and overwrote the original st_name with the dynstr_index. */ sym = e->isym; if (e->isym.st_shndx > 0 && e->isym.st_shndx < SHN_LORESERVE) { s = bfd_section_from_elf_index (e->input_bfd, e->isym.st_shndx); sym.st_shndx = elf_section_data (s->output_section)->this_idx; sym.st_value = (s->output_section->vma + s->output_offset + e->isym.st_value); } if (last_local < e->dynindx) last_local = e->dynindx; elf_swap_symbol_out (abfd, &sym, dynsym + e->dynindx); } } elf_section_data (finfo.dynsym_sec->output_section)->this_hdr.sh_info = last_local + 1; } /* We get the global symbols from the hash table. */ eoinfo.failed = false; eoinfo.localsyms = false; eoinfo.finfo = &finfo; elf_link_hash_traverse (elf_hash_table (info), elf_link_output_extsym, (PTR) &eoinfo); if (eoinfo.failed) return false; /* If backend needs to output some symbols not present in the hash table, do it now. */ if (bed->elf_backend_output_arch_syms) { if (! (*bed->elf_backend_output_arch_syms) (abfd, info, (PTR) &finfo, (boolean (*) PARAMS ((PTR, const char *, Elf_Internal_Sym *, asection *))) elf_link_output_sym)) return false; } /* Flush all symbols to the file. */ if (! elf_link_flush_output_syms (&finfo)) return false; /* Now we know the size of the symtab section. */ off += symtab_hdr->sh_size; /* Finish up and write out the symbol string table (.strtab) section. */ symstrtab_hdr = &elf_tdata (abfd)->strtab_hdr; /* sh_name was set in prep_headers. */ symstrtab_hdr->sh_type = SHT_STRTAB; symstrtab_hdr->sh_flags = 0; symstrtab_hdr->sh_addr = 0; symstrtab_hdr->sh_size = _bfd_stringtab_size (finfo.symstrtab); symstrtab_hdr->sh_entsize = 0; symstrtab_hdr->sh_link = 0; symstrtab_hdr->sh_info = 0; /* sh_offset is set just below. */ symstrtab_hdr->sh_addralign = 1; off = _bfd_elf_assign_file_position_for_section (symstrtab_hdr, off, true); elf_tdata (abfd)->next_file_pos = off; if (bfd_get_symcount (abfd) > 0) { if (bfd_seek (abfd, symstrtab_hdr->sh_offset, SEEK_SET) != 0 || ! _bfd_stringtab_emit (abfd, finfo.symstrtab)) return false; } /* Adjust the relocs to have the correct symbol indices. */ for (o = abfd->sections; o != NULL; o = o->next) { if ((o->flags & SEC_RELOC) == 0) continue; elf_link_adjust_relocs (abfd, &elf_section_data (o)->rel_hdr, elf_section_data (o)->rel_count, elf_section_data (o)->rel_hashes); if (elf_section_data (o)->rel_hdr2 != NULL) elf_link_adjust_relocs (abfd, elf_section_data (o)->rel_hdr2, elf_section_data (o)->rel_count2, (elf_section_data (o)->rel_hashes + elf_section_data (o)->rel_count)); /* Set the reloc_count field to 0 to prevent write_relocs from trying to swap the relocs out itself. */ o->reloc_count = 0; } /* If we are linking against a dynamic object, or generating a shared library, finish up the dynamic linking information. */ if (dynamic) { Elf_External_Dyn *dyncon, *dynconend; /* Fix up .dynamic entries. */ o = bfd_get_section_by_name (dynobj, ".dynamic"); BFD_ASSERT (o != NULL); dyncon = (Elf_External_Dyn *) o->contents; dynconend = (Elf_External_Dyn *) (o->contents + o->_raw_size); for (; dyncon < dynconend; dyncon++) { Elf_Internal_Dyn dyn; const char *name; unsigned int type; elf_swap_dyn_in (dynobj, dyncon, &dyn); switch (dyn.d_tag) { default: break; case DT_INIT: name = info->init_function; goto get_sym; case DT_FINI: name = info->fini_function; get_sym: { struct elf_link_hash_entry *h; h = elf_link_hash_lookup (elf_hash_table (info), name, false, false, true); if (h != NULL && (h->root.type == bfd_link_hash_defined || h->root.type == bfd_link_hash_defweak)) { dyn.d_un.d_val = h->root.u.def.value; o = h->root.u.def.section; if (o->output_section != NULL) dyn.d_un.d_val += (o->output_section->vma + o->output_offset); else { /* The symbol is imported from another shared library and does not apply to this one. */ dyn.d_un.d_val = 0; } elf_swap_dyn_out (dynobj, &dyn, dyncon); } } break; case DT_HASH: name = ".hash"; goto get_vma; case DT_STRTAB: name = ".dynstr"; goto get_vma; case DT_SYMTAB: name = ".dynsym"; goto get_vma; case DT_VERDEF: name = ".gnu.version_d"; goto get_vma; case DT_VERNEED: name = ".gnu.version_r"; goto get_vma; case DT_VERSYM: name = ".gnu.version"; get_vma: o = bfd_get_section_by_name (abfd, name); BFD_ASSERT (o != NULL); dyn.d_un.d_ptr = o->vma; elf_swap_dyn_out (dynobj, &dyn, dyncon); break; case DT_REL: case DT_RELA: case DT_RELSZ: case DT_RELASZ: if (dyn.d_tag == DT_REL || dyn.d_tag == DT_RELSZ) type = SHT_REL; else type = SHT_RELA; dyn.d_un.d_val = 0; for (i = 1; i < elf_elfheader (abfd)->e_shnum; i++) { Elf_Internal_Shdr *hdr; hdr = elf_elfsections (abfd)[i]; if (hdr->sh_type == type && (hdr->sh_flags & SHF_ALLOC) != 0) { if (dyn.d_tag == DT_RELSZ || dyn.d_tag == DT_RELASZ) dyn.d_un.d_val += hdr->sh_size; else { if (dyn.d_un.d_val == 0 || hdr->sh_addr < dyn.d_un.d_val) dyn.d_un.d_val = hdr->sh_addr; } } } elf_swap_dyn_out (dynobj, &dyn, dyncon); break; } } } /* If we have created any dynamic sections, then output them. */ if (dynobj != NULL) { if (! (*bed->elf_backend_finish_dynamic_sections) (abfd, info)) goto error_return; for (o = dynobj->sections; o != NULL; o = o->next) { if ((o->flags & SEC_HAS_CONTENTS) == 0 || o->_raw_size == 0 || o->output_section == bfd_abs_section_ptr) continue; if ((o->flags & SEC_LINKER_CREATED) == 0) { /* At this point, we are only interested in sections created by elf_link_create_dynamic_sections. */ continue; } if ((elf_section_data (o->output_section)->this_hdr.sh_type != SHT_STRTAB) || strcmp (bfd_get_section_name (abfd, o), ".dynstr") != 0) { if (! bfd_set_section_contents (abfd, o->output_section, o->contents, o->output_offset, o->_raw_size)) goto error_return; } else { file_ptr off; /* The contents of the .dynstr section are actually in a stringtab. */ off = elf_section_data (o->output_section)->this_hdr.sh_offset; if (bfd_seek (abfd, off, SEEK_SET) != 0 || ! _bfd_stringtab_emit (abfd, elf_hash_table (info)->dynstr)) goto error_return; } } } /* If we have optimized stabs strings, output them. */ if (elf_hash_table (info)->stab_info != NULL) { if (! _bfd_write_stab_strings (abfd, &elf_hash_table (info)->stab_info)) goto error_return; } if (finfo.symstrtab != NULL) _bfd_stringtab_free (finfo.symstrtab); if (finfo.contents != NULL) free (finfo.contents); if (finfo.external_relocs != NULL) free (finfo.external_relocs); if (finfo.internal_relocs != NULL) free (finfo.internal_relocs); if (finfo.external_syms != NULL) free (finfo.external_syms); if (finfo.internal_syms != NULL) free (finfo.internal_syms); if (finfo.indices != NULL) free (finfo.indices); if (finfo.sections != NULL) free (finfo.sections); if (finfo.symbuf != NULL) free (finfo.symbuf); for (o = abfd->sections; o != NULL; o = o->next) { if ((o->flags & SEC_RELOC) != 0 && elf_section_data (o)->rel_hashes != NULL) free (elf_section_data (o)->rel_hashes); } elf_tdata (abfd)->linker = true; return true; error_return: if (finfo.symstrtab != NULL) _bfd_stringtab_free (finfo.symstrtab); if (finfo.contents != NULL) free (finfo.contents); if (finfo.external_relocs != NULL) free (finfo.external_relocs); if (finfo.internal_relocs != NULL) free (finfo.internal_relocs); if (finfo.external_syms != NULL) free (finfo.external_syms); if (finfo.internal_syms != NULL) free (finfo.internal_syms); if (finfo.indices != NULL) free (finfo.indices); if (finfo.sections != NULL) free (finfo.sections); if (finfo.symbuf != NULL) free (finfo.symbuf); for (o = abfd->sections; o != NULL; o = o->next) { if ((o->flags & SEC_RELOC) != 0 && elf_section_data (o)->rel_hashes != NULL) free (elf_section_data (o)->rel_hashes); } return false; } /* Add a symbol to the output symbol table. */ static boolean elf_link_output_sym (finfo, name, elfsym, input_sec) struct elf_final_link_info *finfo; const char *name; Elf_Internal_Sym *elfsym; asection *input_sec; { boolean (*output_symbol_hook) PARAMS ((bfd *, struct bfd_link_info *info, const char *, Elf_Internal_Sym *, asection *)); output_symbol_hook = get_elf_backend_data (finfo->output_bfd)-> elf_backend_link_output_symbol_hook; if (output_symbol_hook != NULL) { if (! ((*output_symbol_hook) (finfo->output_bfd, finfo->info, name, elfsym, input_sec))) return false; } if (name == (const char *) NULL || *name == '\0') elfsym->st_name = 0; else if (input_sec->flags & SEC_EXCLUDE) elfsym->st_name = 0; else { elfsym->st_name = (unsigned long) _bfd_stringtab_add (finfo->symstrtab, name, true, false); if (elfsym->st_name == (unsigned long) -1) return false; } if (finfo->symbuf_count >= finfo->symbuf_size) { if (! elf_link_flush_output_syms (finfo)) return false; } elf_swap_symbol_out (finfo->output_bfd, elfsym, (PTR) (finfo->symbuf + finfo->symbuf_count)); ++finfo->symbuf_count; ++ bfd_get_symcount (finfo->output_bfd); return true; } /* Flush the output symbols to the file. */ static boolean elf_link_flush_output_syms (finfo) struct elf_final_link_info *finfo; { if (finfo->symbuf_count > 0) { Elf_Internal_Shdr *symtab; symtab = &elf_tdata (finfo->output_bfd)->symtab_hdr; if (bfd_seek (finfo->output_bfd, symtab->sh_offset + symtab->sh_size, SEEK_SET) != 0 || (bfd_write ((PTR) finfo->symbuf, finfo->symbuf_count, sizeof (Elf_External_Sym), finfo->output_bfd) != finfo->symbuf_count * sizeof (Elf_External_Sym))) return false; symtab->sh_size += finfo->symbuf_count * sizeof (Elf_External_Sym); finfo->symbuf_count = 0; } return true; } /* Adjust all external symbols pointing into SEC_MERGE sections to reflect the object merging within the sections. */ static boolean elf_link_sec_merge_syms (h, data) struct elf_link_hash_entry *h; PTR data; { asection *sec; if ((h->root.type == bfd_link_hash_defined || h->root.type == bfd_link_hash_defweak) && ((sec = h->root.u.def.section)->flags & SEC_MERGE) && elf_section_data (sec)->merge_info) { bfd *output_bfd = (bfd *) data; h->root.u.def.value = _bfd_merged_section_offset (output_bfd, &h->root.u.def.section, elf_section_data (sec)->merge_info, h->root.u.def.value, (bfd_vma) 0); } return true; } /* Add an external symbol to the symbol table. This is called from the hash table traversal routine. When generating a shared object, we go through the symbol table twice. The first time we output anything that might have been forced to local scope in a version script. The second time we output the symbols that are still global symbols. */ static boolean elf_link_output_extsym (h, data) struct elf_link_hash_entry *h; PTR data; { struct elf_outext_info *eoinfo = (struct elf_outext_info *) data; struct elf_final_link_info *finfo = eoinfo->finfo; boolean strip; Elf_Internal_Sym sym; asection *input_sec; /* Decide whether to output this symbol in this pass. */ if (eoinfo->localsyms) { if ((h->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) == 0) return true; } else { if ((h->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) != 0) return true; } /* If we are not creating a shared library, and this symbol is referenced by a shared library but is not defined anywhere, then warn that it is undefined. If we do not do this, the runtime linker will complain that the symbol is undefined when the program is run. We don't have to worry about symbols that are referenced by regular files, because we will already have issued warnings for them. */ if (! finfo->info->relocateable && ! finfo->info->allow_shlib_undefined && ! finfo->info->shared && h->root.type == bfd_link_hash_undefined && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) != 0 && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0) { if (! ((*finfo->info->callbacks->undefined_symbol) (finfo->info, h->root.root.string, h->root.u.undef.abfd, (asection *) NULL, 0, true))) { eoinfo->failed = true; return false; } } /* We don't want to output symbols that have never been mentioned by a regular file, or that we have been told to strip. However, if h->indx is set to -2, the symbol is used by a reloc and we must output it. */ if (h->indx == -2) strip = false; else if (((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0 || (h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) != 0) && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0 && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0) strip = true; else if (finfo->info->strip == strip_all || (finfo->info->strip == strip_some && bfd_hash_lookup (finfo->info->keep_hash, h->root.root.string, false, false) == NULL)) strip = true; else strip = false; /* If we're stripping it, and it's not a dynamic symbol, there's nothing else to do unless it is a forced local symbol. */ if (strip && h->dynindx == -1 && (h->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) == 0) return true; sym.st_value = 0; sym.st_size = h->size; sym.st_other = h->other; if ((h->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) != 0) sym.st_info = ELF_ST_INFO (STB_LOCAL, h->type); else if (h->root.type == bfd_link_hash_undefweak || h->root.type == bfd_link_hash_defweak) sym.st_info = ELF_ST_INFO (STB_WEAK, h->type); else sym.st_info = ELF_ST_INFO (STB_GLOBAL, h->type); switch (h->root.type) { default: case bfd_link_hash_new: abort (); return false; case bfd_link_hash_undefined: input_sec = bfd_und_section_ptr; sym.st_shndx = SHN_UNDEF; break; case bfd_link_hash_undefweak: input_sec = bfd_und_section_ptr; sym.st_shndx = SHN_UNDEF; break; case bfd_link_hash_defined: case bfd_link_hash_defweak: { input_sec = h->root.u.def.section; if (input_sec->output_section != NULL) { sym.st_shndx = _bfd_elf_section_from_bfd_section (finfo->output_bfd, input_sec->output_section); if (sym.st_shndx == (unsigned short) -1) { (*_bfd_error_handler) (_("%s: could not find output section %s for input section %s"), bfd_get_filename (finfo->output_bfd), input_sec->output_section->name, input_sec->name); eoinfo->failed = true; return false; } /* ELF symbols in relocateable files are section relative, but in nonrelocateable files they are virtual addresses. */ sym.st_value = h->root.u.def.value + input_sec->output_offset; if (! finfo->info->relocateable) sym.st_value += input_sec->output_section->vma; } else { BFD_ASSERT (input_sec->owner == NULL || (input_sec->owner->flags & DYNAMIC) != 0); sym.st_shndx = SHN_UNDEF; input_sec = bfd_und_section_ptr; } } break; case bfd_link_hash_common: input_sec = h->root.u.c.p->section; sym.st_shndx = SHN_COMMON; sym.st_value = 1 << h->root.u.c.p->alignment_power; break; case bfd_link_hash_indirect: /* These symbols are created by symbol versioning. They point to the decorated version of the name. For example, if the symbol foo@@GNU_1.2 is the default, which should be used when foo is used with no version, then we add an indirect symbol foo which points to foo@@GNU_1.2. We ignore these symbols, since the indirected symbol is already in the hash table. */ return true; case bfd_link_hash_warning: /* We can't represent these symbols in ELF, although a warning symbol may have come from a .gnu.warning.SYMBOL section. We just put the target symbol in the hash table. If the target symbol does not really exist, don't do anything. */ if (h->root.u.i.link->type == bfd_link_hash_new) return true; return (elf_link_output_extsym ((struct elf_link_hash_entry *) h->root.u.i.link, data)); } /* Give the processor backend a chance to tweak the symbol value, and also to finish up anything that needs to be done for this symbol. */ if ((h->dynindx != -1 || (h->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) != 0) && elf_hash_table (finfo->info)->dynamic_sections_created) { struct elf_backend_data *bed; bed = get_elf_backend_data (finfo->output_bfd); if (! ((*bed->elf_backend_finish_dynamic_symbol) (finfo->output_bfd, finfo->info, h, &sym))) { eoinfo->failed = true; return false; } } /* If we are marking the symbol as undefined, and there are no non-weak references to this symbol from a regular object, then mark the symbol as weak undefined; if there are non-weak references, mark the symbol as strong. We can't do this earlier, because it might not be marked as undefined until the finish_dynamic_symbol routine gets through with it. */ if (sym.st_shndx == SHN_UNDEF && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) != 0 && (ELF_ST_BIND(sym.st_info) == STB_GLOBAL || ELF_ST_BIND(sym.st_info) == STB_WEAK)) { int bindtype; if ((h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR_NONWEAK) != 0) bindtype = STB_GLOBAL; else bindtype = STB_WEAK; sym.st_info = ELF_ST_INFO (bindtype, ELF_ST_TYPE (sym.st_info)); } /* If a symbol is not defined locally, we clear the visibility field. */ if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0) sym.st_other ^= ELF_ST_VISIBILITY(sym.st_other); /* If this symbol should be put in the .dynsym section, then put it there now. We have already know the symbol index. We also fill in the entry in the .hash section. */ if (h->dynindx != -1 && elf_hash_table (finfo->info)->dynamic_sections_created) { size_t bucketcount; size_t bucket; size_t hash_entry_size; bfd_byte *bucketpos; bfd_vma chain; sym.st_name = h->dynstr_index; elf_swap_symbol_out (finfo->output_bfd, &sym, (PTR) (((Elf_External_Sym *) finfo->dynsym_sec->contents) + h->dynindx)); bucketcount = elf_hash_table (finfo->info)->bucketcount; bucket = h->elf_hash_value % bucketcount; hash_entry_size = elf_section_data (finfo->hash_sec)->this_hdr.sh_entsize; bucketpos = ((bfd_byte *) finfo->hash_sec->contents + (bucket + 2) * hash_entry_size); chain = bfd_get (8 * hash_entry_size, finfo->output_bfd, bucketpos); bfd_put (8 * hash_entry_size, finfo->output_bfd, h->dynindx, bucketpos); bfd_put (8 * hash_entry_size, finfo->output_bfd, chain, ((bfd_byte *) finfo->hash_sec->contents + (bucketcount + 2 + h->dynindx) * hash_entry_size)); if (finfo->symver_sec != NULL && finfo->symver_sec->contents != NULL) { Elf_Internal_Versym iversym; if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0) { if (h->verinfo.verdef == NULL) iversym.vs_vers = 0; else iversym.vs_vers = h->verinfo.verdef->vd_exp_refno + 1; } else { if (h->verinfo.vertree == NULL) iversym.vs_vers = 1; else iversym.vs_vers = h->verinfo.vertree->vernum + 1; } if ((h->elf_link_hash_flags & ELF_LINK_HIDDEN) != 0) iversym.vs_vers |= VERSYM_HIDDEN; _bfd_elf_swap_versym_out (finfo->output_bfd, &iversym, (((Elf_External_Versym *) finfo->symver_sec->contents) + h->dynindx)); } } /* If we're stripping it, then it was just a dynamic symbol, and there's nothing else to do. */ if (strip) return true; h->indx = bfd_get_symcount (finfo->output_bfd); if (! elf_link_output_sym (finfo, h->root.root.string, &sym, input_sec)) { eoinfo->failed = true; return false; } return true; } /* Copy the relocations indicated by the INTERNAL_RELOCS (which originated from the section given by INPUT_REL_HDR) to the OUTPUT_BFD. */ static void elf_link_output_relocs (output_bfd, input_section, input_rel_hdr, internal_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; Elf_Internal_Shdr *output_rel_hdr; asection *output_section; unsigned int *rel_countp = NULL; struct elf_backend_data *bed; 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; } BFD_ASSERT (output_rel_hdr != NULL); bed = get_elf_backend_data (output_bfd); irela = internal_relocs; irelaend = irela + NUM_SHDR_ENTRIES (input_rel_hdr) * bed->s->int_rels_per_ext_rel; if (input_rel_hdr->sh_entsize == sizeof (Elf_External_Rel)) { Elf_External_Rel *erel; Elf_Internal_Rel *irel; irel = (Elf_Internal_Rel *) bfd_zmalloc (bed->s->int_rels_per_ext_rel * sizeof (Elf_Internal_Rel)); if (irel == NULL) { (*_bfd_error_handler) (_("Error: out of memory")); abort (); } erel = ((Elf_External_Rel *) output_rel_hdr->contents + *rel_countp); for (; irela < irelaend; irela += bed->s->int_rels_per_ext_rel, erel++) { unsigned int i; for (i = 0; i < bed->s->int_rels_per_ext_rel; i++) { irel[i].r_offset = irela[i].r_offset; irel[i].r_info = irela[i].r_info; BFD_ASSERT (irela[i].r_addend == 0); } if (bed->s->swap_reloc_out) (*bed->s->swap_reloc_out) (output_bfd, irel, (PTR) erel); else elf_swap_reloc_out (output_bfd, irel, erel); } free (irel); } else { Elf_External_Rela *erela; BFD_ASSERT (input_rel_hdr->sh_entsize == sizeof (Elf_External_Rela)); erela = ((Elf_External_Rela *) output_rel_hdr->contents + *rel_countp); for (; irela < irelaend; irela += bed->s->int_rels_per_ext_rel, erela++) if (bed->s->swap_reloca_out) (*bed->s->swap_reloca_out) (output_bfd, irela, (PTR) erela); else elf_swap_reloca_out (output_bfd, irela, erela); } /* Bump the counter, so that we know where to add the next set of relocations. */ *rel_countp += NUM_SHDR_ENTRIES (input_rel_hdr); } /* Link an input file into the linker output file. This function handles all the sections and relocations of the input file at once. This is so that we only have to read the local symbols once, and don't have to keep them in memory. */ static boolean elf_link_input_bfd (finfo, input_bfd) struct elf_final_link_info *finfo; bfd *input_bfd; { boolean (*relocate_section) PARAMS ((bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *, Elf_Internal_Rela *, Elf_Internal_Sym *, asection **)); bfd *output_bfd; Elf_Internal_Shdr *symtab_hdr; size_t locsymcount; size_t extsymoff; Elf_External_Sym *external_syms; Elf_External_Sym *esym; Elf_External_Sym *esymend; Elf_Internal_Sym *isym; long *pindex; asection **ppsection; asection *o; struct elf_backend_data *bed; boolean emit_relocs; output_bfd = finfo->output_bfd; bed = get_elf_backend_data (output_bfd); relocate_section = bed->elf_backend_relocate_section; /* If this is a dynamic object, we don't want to do anything here: we don't want the local symbols, and we don't want the section contents. */ if ((input_bfd->flags & DYNAMIC) != 0) return true; emit_relocs = (finfo->info->relocateable || finfo->info->emitrelocations || bed->elf_backend_emit_relocs); symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr; if (elf_bad_symtab (input_bfd)) { locsymcount = symtab_hdr->sh_size / sizeof (Elf_External_Sym); extsymoff = 0; } else { locsymcount = symtab_hdr->sh_info; extsymoff = symtab_hdr->sh_info; } /* Read the local symbols. */ if (symtab_hdr->contents != NULL) external_syms = (Elf_External_Sym *) symtab_hdr->contents; else if (locsymcount == 0) external_syms = NULL; else { external_syms = finfo->external_syms; if (bfd_seek (input_bfd, symtab_hdr->sh_offset, SEEK_SET) != 0 || (bfd_read (external_syms, sizeof (Elf_External_Sym), locsymcount, input_bfd) != locsymcount * sizeof (Elf_External_Sym))) return false; } /* Swap in the local symbols and write out the ones which we know are going into the output file. */ esym = external_syms; esymend = esym + locsymcount; isym = finfo->internal_syms; pindex = finfo->indices; ppsection = finfo->sections; for (; esym < esymend; esym++, isym++, pindex++, ppsection++) { asection *isec; const char *name; Elf_Internal_Sym osym; elf_swap_symbol_in (input_bfd, esym, isym); *pindex = -1; if (elf_bad_symtab (input_bfd)) { if (ELF_ST_BIND (isym->st_info) != STB_LOCAL) { *ppsection = NULL; continue; } } name = NULL; if (isym->st_shndx == SHN_UNDEF) { isec = bfd_und_section_ptr; name = isec->name; } else if (isym->st_shndx > 0 && isym->st_shndx < SHN_LORESERVE) { isec = section_from_elf_index (input_bfd, isym->st_shndx); if (isec && elf_section_data (isec)->merge_info && ELF_ST_TYPE (isym->st_info) != STT_SECTION) isym->st_value = _bfd_merged_section_offset (output_bfd, &isec, elf_section_data (isec)->merge_info, isym->st_value, (bfd_vma) 0); } else if (isym->st_shndx == SHN_ABS) { isec = bfd_abs_section_ptr; name = isec->name; } else if (isym->st_shndx == SHN_COMMON) { isec = bfd_com_section_ptr; name = isec->name; } else { /* Who knows? */ isec = NULL; } *ppsection = isec; /* Don't output the first, undefined, symbol. */ if (esym == external_syms) continue; if (ELF_ST_TYPE (isym->st_info) == STT_SECTION) { asection *ksec; /* Save away all section symbol values. */ if (isec != NULL) { if (name) { if (isec->symbol->value != isym->st_value) (*_bfd_error_handler) (_("%s: invalid section symbol index 0x%x (%s) ingored"), bfd_get_filename (input_bfd), isym->st_shndx, name); continue; } isec->symbol->value = isym->st_value; } /* If this is a discarded link-once section symbol, update it's value to that of the kept section symbol. The linker will keep the first of any matching link-once sections, so we should have already seen it's section symbol. I trust no-one will have the bright idea of re-ordering the bfd list... */ if (isec != NULL && (bfd_get_section_flags (input_bfd, isec) & SEC_LINK_ONCE) != 0 && (ksec = isec->kept_section) != NULL) { isym->st_value = ksec->symbol->value; /* That put the value right, but the section info is all wrong. I hope this works. */ isec->output_offset = ksec->output_offset; isec->output_section = ksec->output_section; } /* We never output section symbols. Instead, we use the section symbol of the corresponding section in the output file. */ continue; } /* If we are stripping all symbols, we don't want to output this one. */ if (finfo->info->strip == strip_all) continue; /* If we are discarding all local symbols, we don't want to output this one. If we are generating a relocateable output file, then some of the local symbols may be required by relocs; we output them below as we discover that they are needed. */ if (finfo->info->discard == discard_all) continue; /* If this symbol is defined in a section which we are discarding, we don't need to keep it, but note that linker_mark is only reliable for sections that have contents. For the benefit of the MIPS ELF linker, we check SEC_EXCLUDE as well as linker_mark. */ if (isym->st_shndx > 0 && isym->st_shndx < SHN_LORESERVE && isec != NULL && ((! isec->linker_mark && (isec->flags & SEC_HAS_CONTENTS) != 0) || (! finfo->info->relocateable && (isec->flags & SEC_EXCLUDE) != 0))) continue; /* Get the name of the symbol. */ name = bfd_elf_string_from_elf_section (input_bfd, symtab_hdr->sh_link, isym->st_name); if (name == NULL) return false; /* See if we are discarding symbols with this name. */ if ((finfo->info->strip == strip_some && (bfd_hash_lookup (finfo->info->keep_hash, name, false, false) == NULL)) || (((finfo->info->discard == discard_sec_merge && (isec->flags & SEC_MERGE) && ! finfo->info->relocateable) || finfo->info->discard == discard_l) && bfd_is_local_label_name (input_bfd, name))) continue; /* If we get here, we are going to output this symbol. */ osym = *isym; /* Adjust the section index for the output file. */ osym.st_shndx = _bfd_elf_section_from_bfd_section (output_bfd, isec->output_section); if (osym.st_shndx == (unsigned short) -1) return false; *pindex = bfd_get_symcount (output_bfd); /* ELF symbols in relocateable files are section relative, but in executable files they are virtual addresses. Note that this code assumes that all ELF sections have an associated BFD section with a reasonable value for output_offset; below we assume that they also have a reasonable value for output_section. Any special sections must be set up to meet these requirements. */ osym.st_value += isec->output_offset; if (! finfo->info->relocateable) osym.st_value += isec->output_section->vma; if (! elf_link_output_sym (finfo, name, &osym, isec)) return false; } /* Relocate the contents of each section. */ for (o = input_bfd->sections; o != NULL; o = o->next) { bfd_byte *contents; if (! o->linker_mark) { /* This section was omitted from the link. */ continue; } if ((o->flags & SEC_HAS_CONTENTS) == 0 || (o->_raw_size == 0 && (o->flags & SEC_RELOC) == 0)) continue; if ((o->flags & SEC_LINKER_CREATED) != 0) { /* Section was created by elf_link_create_dynamic_sections or somesuch. */ continue; } /* Get the contents of the section. They have been cached by a relaxation routine. Note that o is a section in an input file, so the contents field will not have been set by any of the routines which work on output files. */ if (elf_section_data (o)->this_hdr.contents != NULL) contents = elf_section_data (o)->this_hdr.contents; else { contents = finfo->contents; if (! bfd_get_section_contents (input_bfd, o, contents, (file_ptr) 0, o->_raw_size)) return false; } if ((o->flags & SEC_RELOC) != 0) { Elf_Internal_Rela *internal_relocs; /* Get the swapped relocs. */ internal_relocs = (NAME(_bfd_elf,link_read_relocs) (input_bfd, o, finfo->external_relocs, finfo->internal_relocs, false)); if (internal_relocs == NULL && o->reloc_count > 0) return false; /* Relocate the section by invoking a back end routine. The back end routine is responsible for adjusting the section contents as necessary, and (if using Rela relocs and generating a relocateable output file) adjusting the reloc addend as necessary. The back end routine does not have to worry about setting the reloc address or the reloc symbol index. The back end routine is given a pointer to the swapped in internal symbols, and can access the hash table entries for the external symbols via elf_sym_hashes (input_bfd). When generating relocateable output, the back end routine must handle STB_LOCAL/STT_SECTION symbols specially. The output symbol is going to be a section symbol corresponding to the output section, which will require the addend to be adjusted. */ if (! (*relocate_section) (output_bfd, finfo->info, input_bfd, o, contents, internal_relocs, finfo->internal_syms, finfo->sections)) return false; if (emit_relocs) { Elf_Internal_Rela *irela; Elf_Internal_Rela *irelaend; struct elf_link_hash_entry **rel_hash; Elf_Internal_Shdr *input_rel_hdr; unsigned int next_erel; void (* reloc_emitter) PARAMS ((bfd *, asection *, Elf_Internal_Shdr *, Elf_Internal_Rela *)); /* Adjust the reloc addresses and symbol indices. */ irela = internal_relocs; irelaend = irela + o->reloc_count * bed->s->int_rels_per_ext_rel; rel_hash = (elf_section_data (o->output_section)->rel_hashes + elf_section_data (o->output_section)->rel_count + elf_section_data (o->output_section)->rel_count2); for (next_erel = 0; irela < irelaend; irela++, next_erel++) { unsigned long r_symndx; Elf_Internal_Sym *isym; asection *sec; if (next_erel == bed->s->int_rels_per_ext_rel) { rel_hash++; next_erel = 0; } irela->r_offset += o->output_offset; /* Relocs in an executable have to be virtual addresses. */ if (finfo->info->emitrelocations) irela->r_offset += o->output_section->vma; r_symndx = ELF_R_SYM (irela->r_info); if (r_symndx == 0) continue; if (r_symndx >= locsymcount || (elf_bad_symtab (input_bfd) && finfo->sections[r_symndx] == NULL)) { struct elf_link_hash_entry *rh; unsigned long indx; /* This is a reloc against a global symbol. We have not yet output all the local symbols, so we do not know the symbol index of any global symbol. We set the rel_hash entry for this reloc to point to the global hash table entry for this symbol. The symbol index is then set at the end of elf_bfd_final_link. */ indx = r_symndx - extsymoff; rh = elf_sym_hashes (input_bfd)[indx]; while (rh->root.type == bfd_link_hash_indirect || rh->root.type == bfd_link_hash_warning) rh = (struct elf_link_hash_entry *) rh->root.u.i.link; /* Setting the index to -2 tells elf_link_output_extsym that this symbol is used by a reloc. */ BFD_ASSERT (rh->indx < 0); rh->indx = -2; *rel_hash = rh; continue; } /* This is a reloc against a local symbol. */ *rel_hash = NULL; isym = finfo->internal_syms + r_symndx; sec = finfo->sections[r_symndx]; if (ELF_ST_TYPE (isym->st_info) == STT_SECTION) { /* I suppose the backend ought to fill in the section of any STT_SECTION symbol against a processor specific section. If we have discarded a section, the output_section will be the absolute section. */ if (sec != NULL && (bfd_is_abs_section (sec) || (sec->output_section != NULL && bfd_is_abs_section (sec->output_section)))) r_symndx = 0; else if (sec == NULL || sec->owner == NULL) { bfd_set_error (bfd_error_bad_value); return false; } else { r_symndx = sec->output_section->target_index; BFD_ASSERT (r_symndx != 0); } } else { if (finfo->indices[r_symndx] == -1) { unsigned long link; const char *name; asection *osec; if (finfo->info->strip == strip_all) { /* You can't do ld -r -s. */ bfd_set_error (bfd_error_invalid_operation); return false; } /* This symbol was skipped earlier, but since it is needed by a reloc, we must output it now. */ link = symtab_hdr->sh_link; name = bfd_elf_string_from_elf_section (input_bfd, link, isym->st_name); if (name == NULL) return false; osec = sec->output_section; isym->st_shndx = _bfd_elf_section_from_bfd_section (output_bfd, osec); if (isym->st_shndx == (unsigned short) -1) return false; isym->st_value += sec->output_offset; if (! finfo->info->relocateable) isym->st_value += osec->vma; finfo->indices[r_symndx] = bfd_get_symcount (output_bfd); if (! elf_link_output_sym (finfo, name, isym, sec)) return false; } r_symndx = finfo->indices[r_symndx]; } irela->r_info = ELF_R_INFO (r_symndx, ELF_R_TYPE (irela->r_info)); } /* Swap out the relocs. */ if (bed->elf_backend_emit_relocs && ! (finfo->info->relocateable || finfo->info->emitrelocations)) reloc_emitter = bed->elf_backend_emit_relocs; else reloc_emitter = elf_link_output_relocs; input_rel_hdr = &elf_section_data (o)->rel_hdr; (*reloc_emitter) (output_bfd, o, input_rel_hdr, internal_relocs); input_rel_hdr = elf_section_data (o)->rel_hdr2; if (input_rel_hdr) { internal_relocs += NUM_SHDR_ENTRIES (input_rel_hdr) * bed->s->int_rels_per_ext_rel; reloc_emitter (output_bfd, o, input_rel_hdr, internal_relocs); } } } /* Write out the modified section contents. */ if (elf_section_data (o)->stab_info) { if (! (_bfd_write_section_stabs (output_bfd, &elf_hash_table (finfo->info)->stab_info, o, &elf_section_data (o)->stab_info, contents))) return false; } else if (elf_section_data (o)->merge_info) { if (! (_bfd_write_merged_section (output_bfd, o, elf_section_data (o)->merge_info))) return false; } else { if (! (o->flags & SEC_EXCLUDE) && ! bfd_set_section_contents (output_bfd, o->output_section, contents, o->output_offset, (o->_cooked_size != 0 ? o->_cooked_size : o->_raw_size))) return false; } } return true; } /* Generate a reloc when linking an ELF file. This is a reloc requested by the linker, and does come from any input file. This is used to build constructor and destructor tables when linking with -Ur. */ static boolean elf_reloc_link_order (output_bfd, info, output_section, link_order) bfd *output_bfd; struct bfd_link_info *info; asection *output_section; struct bfd_link_order *link_order; { reloc_howto_type *howto; long indx; bfd_vma offset; bfd_vma addend; struct elf_link_hash_entry **rel_hash_ptr; Elf_Internal_Shdr *rel_hdr; struct elf_backend_data *bed = get_elf_backend_data (output_bfd); howto = bfd_reloc_type_lookup (output_bfd, link_order->u.reloc.p->reloc); if (howto == NULL) { bfd_set_error (bfd_error_bad_value); return false; } addend = link_order->u.reloc.p->addend; /* Figure out the symbol index. */ rel_hash_ptr = (elf_section_data (output_section)->rel_hashes + elf_section_data (output_section)->rel_count + elf_section_data (output_section)->rel_count2); if (link_order->type == bfd_section_reloc_link_order) { indx = link_order->u.reloc.p->u.section->target_index; BFD_ASSERT (indx != 0); *rel_hash_ptr = NULL; } else { struct elf_link_hash_entry *h; /* Treat a reloc against a defined symbol as though it were actually against the section. */ h = ((struct elf_link_hash_entry *) bfd_wrapped_link_hash_lookup (output_bfd, info, link_order->u.reloc.p->u.name, false, false, true)); if (h != NULL && (h->root.type == bfd_link_hash_defined || h->root.type == bfd_link_hash_defweak)) { asection *section; section = h->root.u.def.section; indx = section->output_section->target_index; *rel_hash_ptr = NULL; /* It seems that we ought to add the symbol value to the addend here, but in practice it has already been added because it was passed to constructor_callback. */ addend += section->output_section->vma + section->output_offset; } else if (h != NULL) { /* Setting the index to -2 tells elf_link_output_extsym that this symbol is used by a reloc. */ h->indx = -2; *rel_hash_ptr = h; indx = 0; } else { if (! ((*info->callbacks->unattached_reloc) (info, link_order->u.reloc.p->u.name, (bfd *) NULL, (asection *) NULL, (bfd_vma) 0))) return false; indx = 0; } } /* If this is an inplace reloc, we must write the addend into the object file. */ if (howto->partial_inplace && addend != 0) { bfd_size_type size; bfd_reloc_status_type rstat; bfd_byte *buf; boolean ok; size = bfd_get_reloc_size (howto); buf = (bfd_byte *) bfd_zmalloc (size); if (buf == (bfd_byte *) NULL) return false; rstat = _bfd_relocate_contents (howto, output_bfd, addend, buf); switch (rstat) { case bfd_reloc_ok: break; default: case bfd_reloc_outofrange: abort (); case bfd_reloc_overflow: if (! ((*info->callbacks->reloc_overflow) (info, (link_order->type == bfd_section_reloc_link_order ? bfd_section_name (output_bfd, link_order->u.reloc.p->u.section) : link_order->u.reloc.p->u.name), howto->name, addend, (bfd *) NULL, (asection *) NULL, (bfd_vma) 0))) { free (buf); return false; } break; } ok = bfd_set_section_contents (output_bfd, output_section, (PTR) buf, (file_ptr) link_order->offset, size); free (buf); if (! ok) return false; } /* The address of a reloc is relative to the section in a relocateable file, and is a virtual address in an executable file. */ offset = link_order->offset; if (! info->relocateable) offset += output_section->vma; rel_hdr = &elf_section_data (output_section)->rel_hdr; if (rel_hdr->sh_type == SHT_REL) { Elf_Internal_Rel *irel; Elf_External_Rel *erel; unsigned int i; irel = (Elf_Internal_Rel *) bfd_zmalloc (bed->s->int_rels_per_ext_rel * sizeof (Elf_Internal_Rel)); if (irel == NULL) return false; for (i = 0; i < bed->s->int_rels_per_ext_rel; i++) irel[i].r_offset = offset; irel[0].r_info = ELF_R_INFO (indx, howto->type); erel = ((Elf_External_Rel *) rel_hdr->contents + elf_section_data (output_section)->rel_count); if (bed->s->swap_reloc_out) (*bed->s->swap_reloc_out) (output_bfd, irel, (bfd_byte *) erel); else elf_swap_reloc_out (output_bfd, irel, erel); free (irel); } else { Elf_Internal_Rela *irela; Elf_External_Rela *erela; unsigned int i; irela = (Elf_Internal_Rela *) bfd_zmalloc (bed->s->int_rels_per_ext_rel * sizeof (Elf_Internal_Rela)); if (irela == NULL) return false; for (i = 0; i < bed->s->int_rels_per_ext_rel; i++) irela[i].r_offset = offset; irela[0].r_info = ELF_R_INFO (indx, howto->type); irela[0].r_addend = addend; erela = ((Elf_External_Rela *) rel_hdr->contents + elf_section_data (output_section)->rel_count); if (bed->s->swap_reloca_out) (*bed->s->swap_reloca_out) (output_bfd, irela, (bfd_byte *) erela); else elf_swap_reloca_out (output_bfd, irela, erela); } ++elf_section_data (output_section)->rel_count; return true; } /* Allocate a pointer to live in a linker created section. */ boolean elf_create_pointer_linker_section (abfd, info, lsect, h, rel) bfd *abfd; struct bfd_link_info *info; elf_linker_section_t *lsect; struct elf_link_hash_entry *h; const Elf_Internal_Rela *rel; { elf_linker_section_pointers_t **ptr_linker_section_ptr = NULL; elf_linker_section_pointers_t *linker_section_ptr; unsigned long r_symndx = ELF_R_SYM (rel->r_info);; BFD_ASSERT (lsect != NULL); /* Is this a global symbol? */ if (h != NULL) { /* Has this symbol already been allocated, if so, our work is done */ if (_bfd_elf_find_pointer_linker_section (h->linker_section_pointer, rel->r_addend, lsect->which)) return true; ptr_linker_section_ptr = &h->linker_section_pointer; /* Make sure this symbol is output as a dynamic symbol. */ if (h->dynindx == -1) { if (! elf_link_record_dynamic_symbol (info, h)) return false; } if (lsect->rel_section) lsect->rel_section->_raw_size += sizeof (Elf_External_Rela); } else /* Allocation of a pointer to a local symbol */ { elf_linker_section_pointers_t **ptr = elf_local_ptr_offsets (abfd); /* Allocate a table to hold the local symbols if first time */ if (!ptr) { unsigned int num_symbols = elf_tdata (abfd)->symtab_hdr.sh_info; register unsigned int i; ptr = (elf_linker_section_pointers_t **) bfd_alloc (abfd, num_symbols * sizeof (elf_linker_section_pointers_t *)); if (!ptr) return false; elf_local_ptr_offsets (abfd) = ptr; for (i = 0; i < num_symbols; i++) ptr[i] = (elf_linker_section_pointers_t *)0; } /* Has this symbol already been allocated, if so, our work is done */ if (_bfd_elf_find_pointer_linker_section (ptr[r_symndx], rel->r_addend, lsect->which)) return true; ptr_linker_section_ptr = &ptr[r_symndx]; if (info->shared) { /* If we are generating a shared object, we need to output a R_<xxx>_RELATIVE reloc so that the dynamic linker can adjust this GOT entry. */ BFD_ASSERT (lsect->rel_section != NULL); lsect->rel_section->_raw_size += sizeof (Elf_External_Rela); } } /* Allocate space for a pointer in the linker section, and allocate a new pointer record from internal memory. */ BFD_ASSERT (ptr_linker_section_ptr != NULL); linker_section_ptr = (elf_linker_section_pointers_t *) bfd_alloc (abfd, sizeof (elf_linker_section_pointers_t)); if (!linker_section_ptr) return false; linker_section_ptr->next = *ptr_linker_section_ptr; linker_section_ptr->addend = rel->r_addend; linker_section_ptr->which = lsect->which; linker_section_ptr->written_address_p = false; *ptr_linker_section_ptr = linker_section_ptr; #if 0 if (lsect->hole_size && lsect->hole_offset < lsect->max_hole_offset) { linker_section_ptr->offset = lsect->section->_raw_size - lsect->hole_size + (ARCH_SIZE / 8); lsect->hole_offset += ARCH_SIZE / 8; lsect->sym_offset += ARCH_SIZE / 8; if (lsect->sym_hash) /* Bump up symbol value if needed */ { lsect->sym_hash->root.u.def.value += ARCH_SIZE / 8; #ifdef DEBUG fprintf (stderr, "Bump up %s by %ld, current value = %ld\n", lsect->sym_hash->root.root.string, (long)ARCH_SIZE / 8, (long)lsect->sym_hash->root.u.def.value); #endif } } else #endif linker_section_ptr->offset = lsect->section->_raw_size; lsect->section->_raw_size += ARCH_SIZE / 8; #ifdef DEBUG fprintf (stderr, "Create pointer in linker section %s, offset = %ld, section size = %ld\n", lsect->name, (long)linker_section_ptr->offset, (long)lsect->section->_raw_size); #endif return true; } #if ARCH_SIZE==64 #define bfd_put_ptr(BFD,VAL,ADDR) bfd_put_64 (BFD, VAL, ADDR) #endif #if ARCH_SIZE==32 #define bfd_put_ptr(BFD,VAL,ADDR) bfd_put_32 (BFD, VAL, ADDR) #endif /* Fill in the address for a pointer generated in a linker section. */ bfd_vma elf_finish_pointer_linker_section (output_bfd, input_bfd, info, lsect, h, relocation, rel, relative_reloc) bfd *output_bfd; bfd *input_bfd; struct bfd_link_info *info; elf_linker_section_t *lsect; struct elf_link_hash_entry *h; bfd_vma relocation; const Elf_Internal_Rela *rel; int relative_reloc; { elf_linker_section_pointers_t *linker_section_ptr; BFD_ASSERT (lsect != NULL); if (h != NULL) /* global symbol */ { linker_section_ptr = _bfd_elf_find_pointer_linker_section (h->linker_section_pointer, rel->r_addend, lsect->which); BFD_ASSERT (linker_section_ptr != NULL); if (! elf_hash_table (info)->dynamic_sections_created || (info->shared && info->symbolic && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR))) { /* This is actually a static link, or it is a -Bsymbolic link and the symbol is defined locally. We must initialize this entry in the global section. When doing a dynamic link, we create a .rela.<xxx> relocation entry to initialize the value. This is done in the finish_dynamic_symbol routine. */ if (!linker_section_ptr->written_address_p) { linker_section_ptr->written_address_p = true; bfd_put_ptr (output_bfd, relocation + linker_section_ptr->addend, lsect->section->contents + linker_section_ptr->offset); } } } else /* local symbol */ { unsigned long r_symndx = ELF_R_SYM (rel->r_info); BFD_ASSERT (elf_local_ptr_offsets (input_bfd) != NULL); BFD_ASSERT (elf_local_ptr_offsets (input_bfd)[r_symndx] != NULL); linker_section_ptr = _bfd_elf_find_pointer_linker_section (elf_local_ptr_offsets (input_bfd)[r_symndx], rel->r_addend, lsect->which); BFD_ASSERT (linker_section_ptr != NULL); /* Write out pointer if it hasn't been rewritten out before */ if (!linker_section_ptr->written_address_p) { linker_section_ptr->written_address_p = true; bfd_put_ptr (output_bfd, relocation + linker_section_ptr->addend, lsect->section->contents + linker_section_ptr->offset); if (info->shared) { asection *srel = lsect->rel_section; Elf_Internal_Rela *outrel; struct elf_backend_data *bed = get_elf_backend_data (output_bfd); unsigned int i; outrel = (Elf_Internal_Rela *) bfd_zmalloc (sizeof (Elf_Internal_Rela) * bed->s->int_rels_per_ext_rel); if (outrel == NULL) { (*_bfd_error_handler) (_("Error: out of memory")); return 0; } /* We need to generate a relative reloc for the dynamic linker. */ if (!srel) lsect->rel_section = srel = bfd_get_section_by_name (elf_hash_table (info)->dynobj, lsect->rel_name); BFD_ASSERT (srel != NULL); for (i = 0; i < bed->s->int_rels_per_ext_rel; i++) outrel[i].r_offset = (lsect->section->output_section->vma + lsect->section->output_offset + linker_section_ptr->offset); outrel[0].r_info = ELF_R_INFO (0, relative_reloc); outrel[0].r_addend = 0; elf_swap_reloca_out (output_bfd, outrel, (((Elf_External_Rela *) lsect->section->contents) + elf_section_data (lsect->section)->rel_count)); ++elf_section_data (lsect->section)->rel_count; free (outrel); } } } relocation = (lsect->section->output_offset + linker_section_ptr->offset - lsect->hole_offset - lsect->sym_offset); #ifdef DEBUG fprintf (stderr, "Finish pointer in linker section %s, offset = %ld (0x%lx)\n", lsect->name, (long)relocation, (long)relocation); #endif /* Subtract out the addend, because it will get added back in by the normal processing. */ return relocation - linker_section_ptr->addend; } /* Garbage collect unused sections. */ static boolean elf_gc_mark PARAMS ((struct bfd_link_info *info, asection *sec, asection * (*gc_mark_hook) PARAMS ((bfd *, struct bfd_link_info *, Elf_Internal_Rela *, struct elf_link_hash_entry *, Elf_Internal_Sym *)))); static boolean elf_gc_sweep PARAMS ((struct bfd_link_info *info, boolean (*gc_sweep_hook) PARAMS ((bfd *abfd, struct bfd_link_info *info, asection *o, const Elf_Internal_Rela *relocs)))); static boolean elf_gc_sweep_symbol PARAMS ((struct elf_link_hash_entry *h, PTR idxptr)); static boolean elf_gc_allocate_got_offsets PARAMS ((struct elf_link_hash_entry *h, PTR offarg)); static boolean elf_gc_propagate_vtable_entries_used PARAMS ((struct elf_link_hash_entry *h, PTR dummy)); static boolean elf_gc_smash_unused_vtentry_relocs PARAMS ((struct elf_link_hash_entry *h, PTR dummy)); /* The mark phase of garbage collection. For a given section, mark it, and all the sections which define symbols to which it refers. */ static boolean elf_gc_mark (info, sec, gc_mark_hook) struct bfd_link_info *info; asection *sec; asection * (*gc_mark_hook) PARAMS ((bfd *, struct bfd_link_info *, Elf_Internal_Rela *, struct elf_link_hash_entry *, Elf_Internal_Sym *)); { boolean ret = true; sec->gc_mark = 1; /* Look through the section relocs. */ if ((sec->flags & SEC_RELOC) != 0 && sec->reloc_count > 0) { Elf_Internal_Rela *relstart, *rel, *relend; Elf_Internal_Shdr *symtab_hdr; struct elf_link_hash_entry **sym_hashes; size_t nlocsyms; size_t extsymoff; Elf_External_Sym *locsyms, *freesyms = NULL; bfd *input_bfd = sec->owner; struct elf_backend_data *bed = get_elf_backend_data (input_bfd); /* GCFIXME: how to arrange so that relocs and symbols are not reread continually? */ symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr; sym_hashes = elf_sym_hashes (input_bfd); /* Read the local symbols. */ if (elf_bad_symtab (input_bfd)) { nlocsyms = symtab_hdr->sh_size / sizeof (Elf_External_Sym); extsymoff = 0; } else extsymoff = nlocsyms = symtab_hdr->sh_info; if (symtab_hdr->contents) locsyms = (Elf_External_Sym *) symtab_hdr->contents; else if (nlocsyms == 0) locsyms = NULL; else { locsyms = freesyms = bfd_malloc (nlocsyms * sizeof (Elf_External_Sym)); if (freesyms == NULL || bfd_seek (input_bfd, symtab_hdr->sh_offset, SEEK_SET) != 0 || (bfd_read (locsyms, sizeof (Elf_External_Sym), nlocsyms, input_bfd) != nlocsyms * sizeof (Elf_External_Sym))) { ret = false; goto out1; } } /* Read the relocations. */ relstart = (NAME(_bfd_elf,link_read_relocs) (sec->owner, sec, NULL, (Elf_Internal_Rela *) NULL, info->keep_memory)); if (relstart == NULL) { ret = false; goto out1; } relend = relstart + sec->reloc_count * bed->s->int_rels_per_ext_rel; for (rel = relstart; rel < relend; rel++) { unsigned long r_symndx; asection *rsec; struct elf_link_hash_entry *h; Elf_Internal_Sym s; r_symndx = ELF_R_SYM (rel->r_info); if (r_symndx == 0) continue; if (elf_bad_symtab (sec->owner)) { elf_swap_symbol_in (input_bfd, &locsyms[r_symndx], &s); if (ELF_ST_BIND (s.st_info) == STB_LOCAL) rsec = (*gc_mark_hook) (sec->owner, info, rel, NULL, &s); else { h = sym_hashes[r_symndx - extsymoff]; rsec = (*gc_mark_hook) (sec->owner, info, rel, h, NULL); } } else if (r_symndx >= nlocsyms) { h = sym_hashes[r_symndx - extsymoff]; rsec = (*gc_mark_hook) (sec->owner, info, rel, h, NULL); } else { elf_swap_symbol_in (input_bfd, &locsyms[r_symndx], &s); rsec = (*gc_mark_hook) (sec->owner, info, rel, NULL, &s); } if (rsec && !rsec->gc_mark) if (!elf_gc_mark (info, rsec, gc_mark_hook)) { ret = false; goto out2; } } out2: if (!info->keep_memory) free (relstart); out1: if (freesyms) free (freesyms); } return ret; } /* The sweep phase of garbage collection. Remove all garbage sections. */ static boolean elf_gc_sweep (info, gc_sweep_hook) struct bfd_link_info *info; boolean (*gc_sweep_hook) PARAMS ((bfd *abfd, struct bfd_link_info *info, asection *o, const Elf_Internal_Rela *relocs)); { bfd *sub; for (sub = info->input_bfds; sub != NULL; sub = sub->link_next) { asection *o; if (bfd_get_flavour (sub) != bfd_target_elf_flavour) continue; for (o = sub->sections; o != NULL; o = o->next) { /* Keep special sections. Keep .debug sections. */ if ((o->flags & SEC_LINKER_CREATED) || (o->flags & SEC_DEBUGGING)) o->gc_mark = 1; if (o->gc_mark) continue; /* Skip sweeping sections already excluded. */ if (o->flags & SEC_EXCLUDE) continue; /* Since this is early in the link process, it is simple to remove a section from the output. */ o->flags |= SEC_EXCLUDE; /* But we also have to update some of the relocation info we collected before. */ if (gc_sweep_hook && (o->flags & SEC_RELOC) && o->reloc_count > 0) { Elf_Internal_Rela *internal_relocs; boolean r; internal_relocs = (NAME(_bfd_elf,link_read_relocs) (o->owner, o, NULL, NULL, info->keep_memory)); if (internal_relocs == NULL) return false; r = (*gc_sweep_hook) (o->owner, info, o, internal_relocs); if (!info->keep_memory) free (internal_relocs); if (!r) return false; } } } /* Remove the symbols that were in the swept sections from the dynamic symbol table. GCFIXME: Anyone know how to get them out of the static symbol table as well? */ { int i = 0; elf_link_hash_traverse (elf_hash_table (info), elf_gc_sweep_symbol, (PTR) &i); elf_hash_table (info)->dynsymcount = i; } return true; } /* Sweep symbols in swept sections. Called via elf_link_hash_traverse. */ static boolean elf_gc_sweep_symbol (h, idxptr) struct elf_link_hash_entry *h; PTR idxptr; { int *idx = (int *) idxptr; if (h->dynindx != -1 && ((h->root.type != bfd_link_hash_defined && h->root.type != bfd_link_hash_defweak) || h->root.u.def.section->gc_mark)) h->dynindx = (*idx)++; return true; } /* Propogate collected vtable information. This is called through elf_link_hash_traverse. */ static boolean elf_gc_propagate_vtable_entries_used (h, okp) struct elf_link_hash_entry *h; PTR okp; { /* Those that are not vtables. */ if (h->vtable_parent == NULL) return true; /* Those vtables that do not have parents, we cannot merge. */ if (h->vtable_parent == (struct elf_link_hash_entry *) -1) return true; /* If we've already been done, exit. */ if (h->vtable_entries_used && h->vtable_entries_used[-1]) return true; /* Make sure the parent's table is up to date. */ elf_gc_propagate_vtable_entries_used (h->vtable_parent, okp); if (h->vtable_entries_used == NULL) { /* None of this table's entries were referenced. Re-use the parent's table. */ h->vtable_entries_used = h->vtable_parent->vtable_entries_used; h->vtable_entries_size = h->vtable_parent->vtable_entries_size; } else { size_t n; boolean *cu, *pu; /* Or the parent's entries into ours. */ cu = h->vtable_entries_used; cu[-1] = true; pu = h->vtable_parent->vtable_entries_used; if (pu != NULL) { asection *sec = h->root.u.def.section; struct elf_backend_data *bed = get_elf_backend_data (sec->owner); int file_align = bed->s->file_align; n = h->vtable_parent->vtable_entries_size / file_align; while (--n != 0) { if (*pu) *cu = true; pu++, cu++; } } } return true; } static boolean elf_gc_smash_unused_vtentry_relocs (h, okp) struct elf_link_hash_entry *h; PTR okp; { asection *sec; bfd_vma hstart, hend; Elf_Internal_Rela *relstart, *relend, *rel; struct elf_backend_data *bed; int file_align; /* Take care of both those symbols that do not describe vtables as well as those that are not loaded. */ if (h->vtable_parent == NULL) return true; BFD_ASSERT (h->root.type == bfd_link_hash_defined || h->root.type == bfd_link_hash_defweak); sec = h->root.u.def.section; hstart = h->root.u.def.value; hend = hstart + h->size; relstart = (NAME(_bfd_elf,link_read_relocs) (sec->owner, sec, NULL, (Elf_Internal_Rela *) NULL, true)); if (!relstart) return *(boolean *)okp = false; bed = get_elf_backend_data (sec->owner); file_align = bed->s->file_align; relend = relstart + sec->reloc_count * bed->s->int_rels_per_ext_rel; for (rel = relstart; rel < relend; ++rel) if (rel->r_offset >= hstart && rel->r_offset < hend) { /* If the entry is in use, do nothing. */ if (h->vtable_entries_used && (rel->r_offset - hstart) < h->vtable_entries_size) { bfd_vma entry = (rel->r_offset - hstart) / file_align; if (h->vtable_entries_used[entry]) continue; } /* Otherwise, kill it. */ rel->r_offset = rel->r_info = rel->r_addend = 0; } return true; } /* Do mark and sweep of unused sections. */ boolean elf_gc_sections (abfd, info) bfd *abfd; struct bfd_link_info *info; { boolean ok = true; bfd *sub; asection * (*gc_mark_hook) PARAMS ((bfd *abfd, struct bfd_link_info *, Elf_Internal_Rela *, struct elf_link_hash_entry *h, Elf_Internal_Sym *)); if (!get_elf_backend_data (abfd)->can_gc_sections || info->relocateable || info->emitrelocations || elf_hash_table (info)->dynamic_sections_created) return true; /* Apply transitive closure to the vtable entry usage info. */ elf_link_hash_traverse (elf_hash_table (info), elf_gc_propagate_vtable_entries_used, (PTR) &ok); if (!ok) return false; /* Kill the vtable relocations that were not used. */ elf_link_hash_traverse (elf_hash_table (info), elf_gc_smash_unused_vtentry_relocs, (PTR) &ok); if (!ok) return false; /* Grovel through relocs to find out who stays ... */ gc_mark_hook = get_elf_backend_data (abfd)->gc_mark_hook; for (sub = info->input_bfds; sub != NULL; sub = sub->link_next) { asection *o; if (bfd_get_flavour (sub) != bfd_target_elf_flavour) continue; for (o = sub->sections; o != NULL; o = o->next) { if (o->flags & SEC_KEEP) if (!elf_gc_mark (info, o, gc_mark_hook)) return false; } } /* ... and mark SEC_EXCLUDE for those that go. */ if (!elf_gc_sweep(info, get_elf_backend_data (abfd)->gc_sweep_hook)) return false; return true; } /* Called from check_relocs to record the existance of a VTINHERIT reloc. */ boolean elf_gc_record_vtinherit (abfd, sec, h, offset) bfd *abfd; asection *sec; struct elf_link_hash_entry *h; bfd_vma offset; { struct elf_link_hash_entry **sym_hashes, **sym_hashes_end; struct elf_link_hash_entry **search, *child; bfd_size_type extsymcount; /* The sh_info field of the symtab header tells us where the external symbols start. We don't care about the local symbols at this point. */ extsymcount = elf_tdata (abfd)->symtab_hdr.sh_size/sizeof (Elf_External_Sym); if (!elf_bad_symtab (abfd)) extsymcount -= elf_tdata (abfd)->symtab_hdr.sh_info; sym_hashes = elf_sym_hashes (abfd); sym_hashes_end = sym_hashes + extsymcount; /* Hunt down the child symbol, which is in this section at the same offset as the relocation. */ for (search = sym_hashes; search != sym_hashes_end; ++search) { if ((child = *search) != NULL && (child->root.type == bfd_link_hash_defined || child->root.type == bfd_link_hash_defweak) && child->root.u.def.section == sec && child->root.u.def.value == offset) goto win; } (*_bfd_error_handler) ("%s: %s+%lu: No symbol found for INHERIT", bfd_get_filename (abfd), sec->name, (unsigned long)offset); bfd_set_error (bfd_error_invalid_operation); return false; win: if (!h) { /* This *should* only be the absolute section. It could potentially be that someone has defined a non-global vtable though, which would be bad. It isn't worth paging in the local symbols to be sure though; that case should simply be handled by the assembler. */ child->vtable_parent = (struct elf_link_hash_entry *) -1; } else child->vtable_parent = h; return true; } /* Called from check_relocs to record the existance of a VTENTRY reloc. */ boolean elf_gc_record_vtentry (abfd, sec, h, addend) bfd *abfd ATTRIBUTE_UNUSED; asection *sec ATTRIBUTE_UNUSED; struct elf_link_hash_entry *h; bfd_vma addend; { struct elf_backend_data *bed = get_elf_backend_data (abfd); int file_align = bed->s->file_align; if (addend >= h->vtable_entries_size) { size_t size, bytes; boolean *ptr = h->vtable_entries_used; /* While the symbol is undefined, we have to be prepared to handle a zero size. */ if (h->root.type == bfd_link_hash_undefined) size = addend; else { size = h->size; if (size < addend) { /* Oops! We've got a reference past the defined end of the table. This is probably a bug -- shall we warn? */ size = addend; } } /* Allocate one extra entry for use as a "done" flag for the consolidation pass. */ bytes = (size / file_align + 1) * sizeof (boolean); if (ptr) { ptr = bfd_realloc (ptr - 1, bytes); if (ptr != NULL) { size_t oldbytes; oldbytes = (h->vtable_entries_size/file_align + 1) * sizeof (boolean); memset (((char *)ptr) + oldbytes, 0, bytes - oldbytes); } } else ptr = bfd_zmalloc (bytes); if (ptr == NULL) return false; /* And arrange for that done flag to be at index -1. */ h->vtable_entries_used = ptr + 1; h->vtable_entries_size = size; } h->vtable_entries_used[addend / file_align] = true; return true; } /* And an accompanying bit to work out final got entry offsets once we're done. Should be called from final_link. */ boolean elf_gc_common_finalize_got_offsets (abfd, info) bfd *abfd; struct bfd_link_info *info; { bfd *i; struct elf_backend_data *bed = get_elf_backend_data (abfd); bfd_vma gotoff; /* The GOT offset is relative to the .got section, but the GOT header is put into the .got.plt section, if the backend uses it. */ if (bed->want_got_plt) gotoff = 0; else gotoff = bed->got_header_size; /* Do the local .got entries first. */ for (i = info->input_bfds; i; i = i->link_next) { bfd_signed_vma *local_got; bfd_size_type j, locsymcount; Elf_Internal_Shdr *symtab_hdr; if (bfd_get_flavour (i) != bfd_target_elf_flavour) continue; local_got = elf_local_got_refcounts (i); if (!local_got) continue; symtab_hdr = &elf_tdata (i)->symtab_hdr; if (elf_bad_symtab (i)) locsymcount = symtab_hdr->sh_size / sizeof (Elf_External_Sym); else locsymcount = symtab_hdr->sh_info; for (j = 0; j < locsymcount; ++j) { if (local_got[j] > 0) { local_got[j] = gotoff; gotoff += ARCH_SIZE / 8; } else local_got[j] = (bfd_vma) -1; } } /* Then the global .got entries. .plt refcounts are handled by adjust_dynamic_symbol */ elf_link_hash_traverse (elf_hash_table (info), elf_gc_allocate_got_offsets, (PTR) &gotoff); return true; } /* We need a special top-level link routine to convert got reference counts to real got offsets. */ static boolean elf_gc_allocate_got_offsets (h, offarg) struct elf_link_hash_entry *h; PTR offarg; { bfd_vma *off = (bfd_vma *) offarg; if (h->got.refcount > 0) { h->got.offset = off[0]; off[0] += ARCH_SIZE / 8; } else h->got.offset = (bfd_vma) -1; return true; } /* Many folk need no more in the way of final link than this, once got entry reference counting is enabled. */ boolean elf_gc_common_final_link (abfd, info) bfd *abfd; struct bfd_link_info *info; { if (!elf_gc_common_finalize_got_offsets (abfd, info)) return false; /* Invoke the regular ELF backend linker to do all the work. */ return elf_bfd_final_link (abfd, info); } /* This function will be called though elf_link_hash_traverse to store all hash value of the exported symbols in an array. */ static boolean elf_collect_hash_codes (h, data) struct elf_link_hash_entry *h; PTR data; { unsigned long **valuep = (unsigned long **) data; const char *name; char *p; unsigned long ha; char *alc = NULL; /* Ignore indirect symbols. These are added by the versioning code. */ if (h->dynindx == -1) return true; name = h->root.root.string; p = strchr (name, ELF_VER_CHR); if (p != NULL) { alc = bfd_malloc (p - name + 1); memcpy (alc, name, p - name); alc[p - name] = '\0'; name = alc; } /* Compute the hash value. */ ha = bfd_elf_hash (name); /* Store the found hash value in the array given as the argument. */ *(*valuep)++ = ha; /* And store it in the struct so that we can put it in the hash table later. */ h->elf_hash_value = ha; if (alc != NULL) free (alc); return true; }
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