From 52c92c7f75b082b4a7f958b93edbf690fa6128bf Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Tue, 11 Mar 1997 06:46:46 +0000 Subject: [PATCH] From Eric Youngdale : * elf-bfd.h (ELF_LINK_FORCED_LOCAL): Define. * elf.c (bfd_elf_print_symbol): Correct errors in last change. * elflink.h (elf_link_add_object_symbols): Handle cases in which a versioned symbol appears in both a regular and a shared object. (elf_link_assign_sym_version): Set ELF_LINK_FORCED_LOCAL when appropriate. Improve error message. (struct elf_outext_info): Rename from elf_finfo_failed. Change all uses. Add localsyms field. (elf_bfd_final_link): When generating a shared library, call elf_link_output_extsym to output all local symbols. (elf_link_output_extsym): Handle symbols which were forced to become local. --- bfd/elflink.h | 243 +++++++++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 197 insertions(+), 46 deletions(-) diff --git a/bfd/elflink.h b/bfd/elflink.h index 5c1ac67..28df37e 100644 --- a/bfd/elflink.h +++ b/bfd/elflink.h @@ -1058,7 +1058,7 @@ elf_link_add_object_symbols (abfd, info) if (p != NULL && p[1] == ELF_VER_CHR) { char *shortname; - struct elf_link_hash_entry *hi; + struct elf_link_hash_entry *hold; shortname = bfd_hash_allocate (&info->hash->table, p - name + 1); @@ -1067,24 +1067,77 @@ elf_link_add_object_symbols (abfd, info) strncpy (shortname, name, p - name); shortname[p - name] = '\0'; - hi = NULL; - 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; + /* First look to see if we have an existing symbol + with this name. */ + hold = elf_link_hash_lookup (elf_hash_table (info), + shortname, false, false, + false); + + /* If we are looking at a normal object, and the + symbol was seen in a shared object, clobber the + definition in the shared object. */ + if (hold != NULL + && ! dynamic + && (hold->root.type == bfd_link_hash_defined + || hold->root.type == bfd_link_hash_defweak) + && (hold->elf_link_hash_flags + & ELF_LINK_HASH_DEF_DYNAMIC) != 0 + && ((hold->root.u.def.section->owner->flags & DYNAMIC) + != 0)) + { + /* Change the hash table entry to undefined, so + that _bfd_generic_link_add_one_symbol will do + the right thing. */ + hold->root.type = bfd_link_hash_undefined; + hold->root.u.undef.abfd = + hold->root.u.def.section->owner; + hold->verinfo.vertree = NULL; + hold = NULL; + } - if (hi->root.type == bfd_link_hash_indirect) + /* If we are looking at a shared object, and we have + already seen this symbol defined elsewhere, then + don't try to define it again. */ + if (hold != NULL + && dynamic + && (hold->root.type == bfd_link_hash_defined + || hold->root.type == bfd_link_hash_defweak + || hold->root.type == bfd_link_hash_indirect + || (hold->root.type == bfd_link_hash_common + && (bind == STB_WEAK + || ELF_ST_TYPE (sym.st_info) == STT_FUNC)))) + { + /* Don't add an indirect symbol. */ + } + else { - hi->elf_link_hash_flags &= ~ ELF_LINK_NON_ELF; - if (dynamic) - hi->elf_link_hash_flags |= ELF_LINK_HASH_DEF_DYNAMIC; - /* We don't set DEF_REGULAR because we don't the - symbol to get exported even if we are - exporting all defined symbols. FIXME: What a - hack. */ - /* FIXME: Do we need to copy any flags from H to - HI? */ + struct elf_link_hash_entry *hi; + + hi = NULL; + 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) + { + hi->elf_link_hash_flags &= ~ ELF_LINK_NON_ELF; + if (dynamic) + hi->elf_link_hash_flags |= + ELF_LINK_HASH_DEF_DYNAMIC; + /* We don't set DEF_REGULAR because we don't + the symbol to get exported even if we are + exporting all defined symbols. FIXME: + What a hack. */ + /* FIXME: Do we need to copy any flags from + H to HI? */ + } } /* We also need to define an indirection from the @@ -1097,18 +1150,77 @@ elf_link_add_object_symbols (abfd, info) strncpy (shortname, name, p - name); strcpy (shortname + (p - name), p + 1); - hi = NULL; - 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; + /* First look to see if we have an existing symbol + with this name. */ + hold = elf_link_hash_lookup (elf_hash_table (info), + shortname, false, false, + false); + + /* If we are looking at a normal object, and the + symbol was seen in a shared object, clobber the + definition in the shared object. */ + if (hold != NULL + && ! dynamic + && (hold->root.type == bfd_link_hash_defined + || hold->root.type == bfd_link_hash_defweak) + && (hold->elf_link_hash_flags + & ELF_LINK_HASH_DEF_DYNAMIC) != 0 + && ((hold->root.u.def.section->owner->flags & DYNAMIC) + != 0)) + { + /* Change the hash table entry to undefined, so + that _bfd_generic_link_add_one_symbol will do + the right thing. */ + hold->root.type = bfd_link_hash_undefined; + hold->root.u.undef.abfd = + hold->root.u.def.section->owner; + hold->verinfo.vertree = NULL; + hold = NULL; + } - if (hi->root.type == bfd_link_hash_indirect) + /* If we are looking at a shared object, and we have + already seen this symbol defined elsewhere, then + don't try to define it again. */ + if (hold != NULL + && dynamic + && (hold->root.type == bfd_link_hash_defined + || hold->root.type == bfd_link_hash_defweak + || hold->root.type == bfd_link_hash_indirect + || (hold->root.type == bfd_link_hash_common + && (bind == STB_WEAK + || ELF_ST_TYPE (sym.st_info) == STT_FUNC)))) { - hi->elf_link_hash_flags &= ~ ELF_LINK_NON_ELF; - if (dynamic) - hi->elf_link_hash_flags |= ELF_LINK_HASH_DEF_DYNAMIC; + /* Don't add an indirect symbol. */ + } + else + { + struct elf_link_hash_entry *hi; + + hi = NULL; + 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) + { + hi->elf_link_hash_flags &= ~ ELF_LINK_NON_ELF; + if (dynamic) + hi->elf_link_hash_flags |= + ELF_LINK_HASH_DEF_DYNAMIC; + /* We don't set DEF_REGULAR because we don't + the symbol to get exported even if we are + exporting all defined symbols. FIXME: + What a hack. */ + /* FIXME: Do we need to copy any flags from + H to HI? */ + } } } } @@ -2602,6 +2714,7 @@ elf_link_assign_sym_version (h, data) & ELF_LINK_HASH_NEEDS_PLT) == 0) { sinfo->removed_dynamic = true; + h->elf_link_hash_flags |= ELF_LINK_FORCED_LOCAL; h->dynindx = -1; /* FIXME: The name of the symbol has already been recorded in the dynamic @@ -2661,8 +2774,8 @@ elf_link_assign_sym_version (h, data) /* We could not find the version for a symbol when generating a shared archive. Return an error. */ (*_bfd_error_handler) - ("%s: invalid version %s", bfd_get_filename (sinfo->output_bfd), - h->root.root.string); + ("%s: undefined version name %s", + bfd_get_filename (sinfo->output_bfd), h->root.root.string); bfd_set_error (bfd_error_bad_value); sinfo->failed = true; return false; @@ -2717,6 +2830,7 @@ elf_link_assign_sym_version (h, data) & ELF_LINK_HASH_NEEDS_PLT) == 0) { sinfo->removed_dynamic = true; + h->elf_link_hash_flags |= ELF_LINK_FORCED_LOCAL; h->dynindx = -1; /* FIXME: The name of the symbol has already been recorded in the dynamic string table @@ -2740,6 +2854,7 @@ elf_link_assign_sym_version (h, data) && (h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) == 0) { sinfo->removed_dynamic = true; + h->elf_link_hash_flags |= ELF_LINK_FORCED_LOCAL; h->dynindx = -1; /* FIXME: The name of the symbol has already been recorded in the dynamic string table section. */ @@ -2827,12 +2942,12 @@ 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 routines called via - elf_link_hash_traverse which must return failure. */ +/* This struct is used to pass information to elf_link_output_extsym. */ -struct elf_finfo_failed +struct elf_outext_info { boolean failed; + boolean localsyms; struct elf_final_link_info *finfo; }; @@ -2859,7 +2974,7 @@ elf_bfd_final_link (abfd, info) Elf_Internal_Shdr *symtab_hdr; Elf_Internal_Shdr *symstrtab_hdr; struct elf_backend_data *bed = get_elf_backend_data (abfd); - struct elf_finfo_failed eif; + struct elf_outext_info eoinfo; if (info->shared) abfd->flags |= DYNAMIC; @@ -3196,6 +3311,23 @@ elf_bfd_final_link (abfd, info) /* That wrote out all the local symbols. Finish up the symbol table with the global symbols. */ + if (info->strip != strip_all && 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 = abfd->symcount; @@ -3203,11 +3335,12 @@ elf_bfd_final_link (abfd, info) elf_section_data (finfo.dynsym_sec->output_section)->this_hdr.sh_info = 1; /* We get the global symbols from the hash table. */ - eif.failed = false; - eif.finfo = &finfo; + eoinfo.failed = false; + eoinfo.localsyms = false; + eoinfo.finfo = &finfo; elf_link_hash_traverse (elf_hash_table (info), elf_link_output_extsym, - (PTR) &eif); - if (eif.failed) + (PTR) &eoinfo); + if (eoinfo.failed) return false; /* Flush all symbols to the file. */ @@ -3592,19 +3725,35 @@ elf_link_flush_output_syms (finfo) } /* Add an external symbol to the symbol table. This is called from - the hash table traversal routine. */ + 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_finfo_failed *eif = (struct elf_finfo_failed *) data; - struct elf_final_link_info *finfo = eif->finfo; + 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 @@ -3622,7 +3771,7 @@ elf_link_output_extsym (h, data) (finfo->info, h->root.root.string, h->root.u.undef.abfd, (asection *) NULL, 0))) { - eif->failed = true; + eoinfo->failed = true; return false; } } @@ -3655,8 +3804,10 @@ elf_link_output_extsym (h, data) sym.st_value = 0; sym.st_size = h->size; sym.st_other = h->other; - if (h->root.type == bfd_link_hash_undefweak - || h->root.type == bfd_link_hash_defweak) + 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); @@ -3689,7 +3840,7 @@ elf_link_output_extsym (h, data) input_sec->output_section); if (sym.st_shndx == (unsigned short) -1) { - eif->failed = true; + eoinfo->failed = true; return false; } @@ -3761,7 +3912,7 @@ elf_link_output_extsym (h, data) if (! ((*bed->elf_backend_finish_dynamic_symbol) (finfo->output_bfd, finfo->info, h, &sym))) { - eif->failed = true; + eoinfo->failed = true; return false; } @@ -3835,7 +3986,7 @@ elf_link_output_extsym (h, data) if (! elf_link_output_sym (finfo, h->root.root.string, &sym, input_sec)) { - eif->failed = true; + eoinfo->failed = true; return false; } -- 2.7.4