X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=bfd%2Felfxx-x86.c;h=7ccfd2581526ea4e71044bef1fb1f127537c1d6b;hb=b7dc48b4a8006abb552c5e7d22f9841c86f2537d;hp=3899c137dcfd6709a536ded60d19158fcc6aa025;hpb=92f402a7e03f5d747bc9a09c8da2f61cc539ac33;p=deliverable%2Fbinutils-gdb.git diff --git a/bfd/elfxx-x86.c b/bfd/elfxx-x86.c index 3899c137dc..7ccfd25815 100644 --- a/bfd/elfxx-x86.c +++ b/bfd/elfxx-x86.c @@ -1,5 +1,5 @@ /* x86 specific support for ELF - Copyright (C) 2017 Free Software Foundation, Inc. + Copyright (C) 2017-2018 Free Software Foundation, Inc. This file is part of BFD, the Binary File Descriptor library. @@ -119,7 +119,7 @@ elf_x86_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf) && h->got.refcount > 0) { /* Don't use the regular PLT if there are both GOT and GOTPLT - reloctions. */ + reloctions. */ h->plt.offset = (bfd_vma) -1; /* Use the GOT PLT. */ @@ -179,6 +179,7 @@ elf_x86_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf) asection *s = htab->elf.splt; asection *second_s = htab->plt_second; asection *got_s = htab->plt_got; + bfd_boolean use_plt; /* If this is the first .plt entry, make room for the special first entry. The .plt section is used by prelink to undo @@ -196,12 +197,19 @@ elf_x86_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf) } /* If this symbol is not defined in a regular file, and we are - not generating a shared library, then set the symbol to this - location in the .plt. This is required to make function - pointers compare as equal between the normal executable and - the shared library. */ - if (! bfd_link_pic (info) - && !h->def_regular) + generating PDE, then set the symbol to this location in the + .plt. This is required to make function pointers compare + as equal between PDE and the shared library. + + NB: If PLT is PC-relative, we can use the .plt in PIE for + function address. */ + if (h->def_regular) + use_plt = FALSE; + else if (htab->pcrel_plt) + use_plt = ! bfd_link_dll (info); + else + use_plt = bfd_link_pde (info); + if (use_plt) { if (use_plt_got) { @@ -521,45 +529,58 @@ elf_x86_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf) return TRUE; } -/* Find any dynamic relocs that apply to read-only sections. */ +/* Find dynamic relocs for H that apply to read-only sections. */ -bfd_boolean -_bfd_x86_elf_readonly_dynrelocs (struct elf_link_hash_entry *h, - void *inf) +static asection * +readonly_dynrelocs (struct elf_link_hash_entry *h) { - struct elf_x86_link_hash_entry *eh; struct elf_dyn_relocs *p; + for (p = elf_x86_hash_entry (h)->dyn_relocs; p != NULL; p = p->next) + { + asection *s = p->sec->output_section; + + if (s != NULL && (s->flags & SEC_READONLY) != 0) + return p->sec; + } + return NULL; +} + +/* Set DF_TEXTREL if we find any dynamic relocs that apply to + read-only sections. */ + +static bfd_boolean +maybe_set_textrel (struct elf_link_hash_entry *h, void *inf) +{ + asection *sec; + + if (h->root.type == bfd_link_hash_indirect) + return TRUE; + /* Skip local IFUNC symbols. */ if (h->forced_local && h->type == STT_GNU_IFUNC) return TRUE; - eh = (struct elf_x86_link_hash_entry *) h; - for (p = eh->dyn_relocs; p != NULL; p = p->next) + sec = readonly_dynrelocs (h); + if (sec != NULL) { - asection *s = p->sec->output_section; + struct bfd_link_info *info = (struct bfd_link_info *) inf; - if (s != NULL && (s->flags & SEC_READONLY) != 0) - { - struct bfd_link_info *info = (struct bfd_link_info *) inf; + info->flags |= DF_TEXTREL; + /* xgettext:c-format */ + info->callbacks->minfo (_("%pB: dynamic relocation against `%pT' " + "in read-only section `%pA'\n"), + sec->owner, h->root.root.string, sec); - info->flags |= DF_TEXTREL; - - if ((info->warn_shared_textrel && bfd_link_pic (info)) - || info->error_textrel) - /* xgettext:c-format */ - info->callbacks->einfo (_("%P: %B: warning: relocation against `%s' in readonly section `%A'\n"), - p->sec->owner, h->root.root.string, - p->sec); - else - /* xgettext:c-format */ - info->callbacks->minfo - (_("%B: dynamic relocation against `%T' in read-only section `%A'\n"), - p->sec->owner, h->root.root.string, p->sec); + if ((info->warn_shared_textrel && bfd_link_pic (info)) + || info->error_textrel) + /* xgettext:c-format */ + info->callbacks->einfo (_("%P: %pB: warning: relocation against `%s' " + "in read-only section `%pA'\n"), + sec->owner, h->root.root.string, sec); - /* Not an error, just cut short the traversal. */ - return FALSE; - } + /* Not an error, just cut short the traversal. */ + return FALSE; } return TRUE; } @@ -758,6 +779,7 @@ _bfd_x86_elf_link_hash_table_create (bfd *abfd) ret->dt_reloc_sz = DT_RELASZ; ret->dt_reloc_ent = DT_RELAENT; ret->got_entry_size = 8; + ret->pcrel_plt = TRUE; ret->tls_get_addr = "__tls_get_addr"; } if (ABI_64_P (abfd)) @@ -785,6 +807,7 @@ _bfd_x86_elf_link_hash_table_create (bfd *abfd) ret->dt_reloc_ent = DT_RELENT; ret->sizeof_reloc = sizeof (Elf32_External_Rel); ret->got_entry_size = 4; + ret->pcrel_plt = FALSE; ret->pointer_r_type = R_386_32; ret->dynamic_interpreter = ELF32_DYNAMIC_INTERPRETER; ret->dynamic_interpreter_size @@ -826,6 +849,54 @@ _bfd_x86_elf_compare_relocs (const void *ap, const void *bp) return 0; } +/* Mark symbol, NAME, as locally defined by linker if it is referenced + and not defined in a relocatable object file. */ + +static void +elf_x86_linker_defined (struct bfd_link_info *info, const char *name) +{ + struct elf_link_hash_entry *h; + + h = elf_link_hash_lookup (elf_hash_table (info), name, + FALSE, FALSE, FALSE); + if (h == NULL) + return; + + 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_new + || h->root.type == bfd_link_hash_undefined + || h->root.type == bfd_link_hash_undefweak + || h->root.type == bfd_link_hash_common + || (!h->def_regular && h->def_dynamic)) + { + elf_x86_hash_entry (h)->local_ref = 2; + elf_x86_hash_entry (h)->linker_def = 1; + } +} + +/* Hide a linker-defined symbol, NAME, with hidden visibility. */ + +static void +elf_x86_hide_linker_defined (struct bfd_link_info *info, + const char *name) +{ + struct elf_link_hash_entry *h; + + h = elf_link_hash_lookup (elf_hash_table (info), name, + FALSE, FALSE, FALSE); + if (h == NULL) + return; + + while (h->root.type == bfd_link_hash_indirect) + h = (struct elf_link_hash_entry *) h->root.u.i.link; + + if (ELF_ST_VISIBILITY (h->other) == STV_INTERNAL + || ELF_ST_VISIBILITY (h->other) == STV_HIDDEN) + _bfd_elf_link_hash_hide_symbol (info, h, TRUE); +} + bfd_boolean _bfd_x86_elf_link_check_relocs (bfd *abfd, struct bfd_link_info *info) { @@ -843,21 +914,36 @@ _bfd_x86_elf_link_check_relocs (bfd *abfd, struct bfd_link_info *info) htab->tls_get_addr, FALSE, FALSE, FALSE); if (h != NULL) - elf_x86_hash_entry (h)->tls_get_addr = 1; + { + elf_x86_hash_entry (h)->tls_get_addr = 1; + + /* Check the versioned __tls_get_addr symbol. */ + while (h->root.type == bfd_link_hash_indirect) + { + h = (struct elf_link_hash_entry *) h->root.u.i.link; + elf_x86_hash_entry (h)->tls_get_addr = 1; + } + } /* "__ehdr_start" will be defined by linker as a hidden symbol later if it is referenced and not defined. */ - h = elf_link_hash_lookup (elf_hash_table (info), - "__ehdr_start", - FALSE, FALSE, FALSE); - if (h != NULL - && (h->root.type == bfd_link_hash_new - || h->root.type == bfd_link_hash_undefined - || h->root.type == bfd_link_hash_undefweak - || h->root.type == bfd_link_hash_common)) + elf_x86_linker_defined (info, "__ehdr_start"); + + if (bfd_link_executable (info)) { - elf_x86_hash_entry (h)->local_ref = 2; - elf_x86_hash_entry (h)->linker_def = 1; + /* References to __bss_start, _end and _edata should be + locally resolved within executables. */ + elf_x86_linker_defined (info, "__bss_start"); + elf_x86_linker_defined (info, "_end"); + elf_x86_linker_defined (info, "_edata"); + } + else + { + /* Hide hidden __bss_start, _end and _edata in shared + libraries. */ + elf_x86_hide_linker_defined (info, "__bss_start"); + elf_x86_hide_linker_defined (info, "_end"); + elf_x86_hide_linker_defined (info, "_edata"); } } } @@ -937,8 +1023,10 @@ _bfd_x86_elf_size_dynamic_sections (bfd *output_bfd, if ((info->warn_shared_textrel && bfd_link_pic (info)) || info->error_textrel) /* xgettext:c-format */ - info->callbacks->einfo (_("%P: %B: warning: relocation in readonly section `%A'\n"), - p->sec->owner, p->sec); + info->callbacks->einfo + (_("%P: %pB: warning: relocation " + "in read-only section `%pA'\n"), + p->sec->owner, p->sec); } } } @@ -1002,7 +1090,7 @@ _bfd_x86_elf_size_dynamic_sections (bfd *output_bfd, if (htab->tls_ld_or_ldm_got.refcount > 0) { /* Allocate 2 got entries and 1 dynamic reloc for R_386_TLS_LDM - or R_X86_64_TLSLD relocs. */ + or R_X86_64_TLSLD relocs. */ htab->tls_ld_or_ldm_got.offset = htab->elf.sgot->size; htab->elf.sgot->size += 2 * htab->got_entry_size; htab->elf.srelgot->size += htab->sizeof_reloc; @@ -1062,7 +1150,7 @@ _bfd_x86_elf_size_dynamic_sections (bfd *output_bfd, /* Don't allocate .got.plt section if there are no GOT nor PLT entries and there is no reference to _GLOBAL_OFFSET_TABLE_. */ if ((htab->elf.hgot == NULL - || !htab->elf.hgot->ref_regular_nonweak) + || !htab->got_referenced) && (htab->elf.sgotplt->size == bed->got_header_size) && (htab->elf.splt == NULL || htab->elf.splt->size == 0) @@ -1072,7 +1160,22 @@ _bfd_x86_elf_size_dynamic_sections (bfd *output_bfd, || htab->elf.iplt->size == 0) && (htab->elf.igotplt == NULL || htab->elf.igotplt->size == 0)) - htab->elf.sgotplt->size = 0; + { + htab->elf.sgotplt->size = 0; + /* Solaris requires to keep _GLOBAL_OFFSET_TABLE_ even if it + isn't used. */ + if (htab->elf.hgot != NULL && htab->target_os != is_solaris) + { + /* Remove the unused _GLOBAL_OFFSET_TABLE_ from symbol + table. */ + htab->elf.hgot->root.type = bfd_link_hash_undefined; + htab->elf.hgot->root.u.undef.abfd + = htab->elf.hgot->root.u.def.section->owner; + htab->elf.hgot->root.linker_def = 0; + htab->elf.hgot->ref_regular = 0; + htab->elf.hgot->def_regular = 0; + } + } } if (_bfd_elf_eh_frame_present (info)) @@ -1262,16 +1365,15 @@ _bfd_x86_elf_size_dynamic_sections (bfd *output_bfd, /* If any dynamic relocs apply to a read-only section, then we need a DT_TEXTREL entry. */ if ((info->flags & DF_TEXTREL) == 0) - elf_link_hash_traverse (&htab->elf, - _bfd_x86_elf_readonly_dynrelocs, - info); + elf_link_hash_traverse (&htab->elf, maybe_set_textrel, info); if ((info->flags & DF_TEXTREL) != 0) { if (htab->readonly_dynrelocs_against_ifunc) { info->callbacks->einfo - (_("%P%X: read-only segment has dynamic IFUNC relocations; recompile with -fPIC\n")); + (_("%P%X: read-only segment has dynamic IFUNC relocations;" + " recompile with -fPIC\n")); bfd_set_error (bfd_error_bad_value); return FALSE; } @@ -1319,7 +1421,7 @@ _bfd_x86_elf_finish_dynamic_sections (bfd *output_bfd, if (bfd_is_abs_section (htab->elf.sgotplt->output_section)) { _bfd_error_handler - (_("discarded output section: `%A'"), htab->elf.sgotplt); + (_("discarded output section: `%pA'"), htab->elf.sgotplt); return NULL; } @@ -1331,7 +1433,7 @@ _bfd_x86_elf_finish_dynamic_sections (bfd *output_bfd, : sdyn->output_section->vma + sdyn->output_offset); /* Set the first entry in the global offset table to the address - of the dynamic section. Write GOT[1] and GOT[2], needed for + of the dynamic section. Write GOT[1] and GOT[2], needed for the dynamic linker. */ if (htab->got_entry_size == 8) { @@ -1657,6 +1759,52 @@ _bfd_x86_elf_fixup_symbol (struct bfd_link_info *info, return TRUE; } +/* Change the STT_GNU_IFUNC symbol defined in position-dependent + executable into the normal function symbol and set its address + to its PLT entry, which should be resolved by R_*_IRELATIVE at + run-time. */ + +void +_bfd_x86_elf_link_fixup_ifunc_symbol (struct bfd_link_info *info, + struct elf_x86_link_hash_table *htab, + struct elf_link_hash_entry *h, + Elf_Internal_Sym *sym) +{ + if (bfd_link_pde (info) + && h->def_regular + && h->dynindx != -1 + && h->plt.offset != (bfd_vma) -1 + && h->type == STT_GNU_IFUNC + && h->pointer_equality_needed) + { + asection *plt_s; + bfd_vma plt_offset; + bfd *output_bfd = info->output_bfd; + + if (htab->plt_second) + { + struct elf_x86_link_hash_entry *eh + = (struct elf_x86_link_hash_entry *) h; + + plt_s = htab->plt_second; + plt_offset = eh->plt_second.offset; + } + else + { + plt_s = htab->elf.splt; + plt_offset = h->plt.offset; + } + + sym->st_size = 0; + sym->st_info = ELF_ST_INFO (ELF_ST_BIND (sym->st_info), STT_FUNC); + sym->st_shndx + = _bfd_elf_section_from_bfd_section (output_bfd, + plt_s->output_section); + sym->st_value = (plt_s->output_section->vma + + plt_s->output_offset + plt_offset); + } +} + /* Return TRUE if symbol should be hashed in the `.gnu.hash' section. */ bfd_boolean @@ -1824,17 +1972,10 @@ _bfd_x86_elf_adjust_dynamic_symbol (struct bfd_link_info *info, || (!eh->gotoff_ref && htab->target_os != is_vxworks))) { - for (p = eh->dyn_relocs; p != NULL; p = p->next) - { - s = p->sec->output_section; - if (s != NULL && (s->flags & SEC_READONLY) != 0) - break; - } - - /* If we didn't find any dynamic relocs in read-only sections, + /* If we don't find any dynamic relocs in read-only sections, then we'll be keeping the dynamic relocs and avoiding the copy reloc. */ - if (p == NULL) + if (!readonly_dynrelocs (h)) { h->non_got_ref = 0; return TRUE; @@ -1926,10 +2067,8 @@ _bfd_x86_elf_link_symbol_references_local (struct bfd_link_info *info, && htab->interp == NULL) || info->dynamic_undefined_weak == 0)) || ((h->def_regular || ELF_COMMON_DEF_P (h)) - && h->versioned == unversioned && info->version_info != NULL - && bfd_hide_sym_by_version (info->version_info, - h->root.root.string))) + && _bfd_elf_link_hide_sym_by_version (info, h))) { eh->local_ref = 2; return TRUE; @@ -2231,10 +2370,10 @@ _bfd_x86_elf_parse_gnu_properties (bfd *abfd, unsigned int type, { _bfd_error_handler ((type == GNU_PROPERTY_X86_ISA_1_USED - ? _("error: %B: ") + ? _("error: %pB: ") : (type == GNU_PROPERTY_X86_ISA_1_NEEDED - ? _("error: %B: ") - : _("error: %B: "))), + ? _("error: %pB: ") + : _("error: %pB: "))), abfd, datasz); return property_corrupt; } @@ -2268,18 +2407,54 @@ _bfd_x86_elf_merge_gnu_properties (struct bfd_link_info *info, switch (pr_type) { case GNU_PROPERTY_X86_ISA_1_USED: + if (aprop == NULL || bprop == NULL) + { + /* Only one of APROP and BPROP can be NULL. */ + if (aprop != NULL) + { + /* Remove this property since the other input file doesn't + have it. */ + aprop->pr_kind = property_remove; + updated = TRUE; + } + break; + } + goto or_property; + case GNU_PROPERTY_X86_ISA_1_NEEDED: if (aprop != NULL && bprop != NULL) { +or_property: number = aprop->u.number; aprop->u.number = number | bprop->u.number; - updated = number != (unsigned int) aprop->u.number; + /* Remove the property if all bits are empty. */ + if (aprop->u.number == 0) + { + aprop->pr_kind = property_remove; + updated = TRUE; + } + else + updated = number != (unsigned int) aprop->u.number; } else { - /* Return TRUE if APROP is NULL to indicate that BPROP should - be added to ABFD. */ - updated = aprop == NULL; + /* Only one of APROP and BPROP can be NULL. */ + if (aprop != NULL) + { + if (aprop->u.number == 0) + { + /* Remove APROP if all bits are empty. */ + aprop->pr_kind = property_remove; + updated = TRUE; + } + } + else + { + /* Return TRUE if APROP is NULL and all bits of BPROP + aren't empty to indicate that BPROP should be added + to ABFD. */ + updated = bprop->u.number != 0; + } } break; @@ -2364,6 +2539,7 @@ _bfd_x86_elf_link_setup_gnu_properties const struct elf_backend_data *bed; unsigned int class_align = ABI_64_P (info->output_bfd) ? 3 : 2; unsigned int got_align; + bfd_boolean has_text = FALSE; features = 0; if (info->ibt) @@ -2378,24 +2554,59 @@ _bfd_x86_elf_link_setup_gnu_properties if (bfd_get_flavour (pbfd) == bfd_target_elf_flavour && bfd_count_sections (pbfd) != 0) { + if (!has_text) + { + /* Check if there is no non-empty text section. */ + sec = bfd_get_section_by_name (pbfd, ".text"); + if (sec != NULL && sec->size != 0) + has_text = TRUE; + } + ebfd = pbfd; if (elf_properties (pbfd) != NULL) break; } - if (ebfd != NULL && features) + bed = get_elf_backend_data (info->output_bfd); + + htab = elf_x86_hash_table (info, bed->target_id); + if (htab == NULL) + return pbfd; + + if (ebfd != NULL) { - /* If features is set, add GNU_PROPERTY_X86_FEATURE_1_IBT and - GNU_PROPERTY_X86_FEATURE_1_SHSTK. */ - prop = _bfd_elf_get_property (ebfd, - GNU_PROPERTY_X86_FEATURE_1_AND, - 4); - prop->u.number |= features; - prop->pr_kind = property_number; + prop = NULL; + if (features) + { + /* If features is set, add GNU_PROPERTY_X86_FEATURE_1_IBT and + GNU_PROPERTY_X86_FEATURE_1_SHSTK. */ + prop = _bfd_elf_get_property (ebfd, + GNU_PROPERTY_X86_FEATURE_1_AND, + 4); + prop->u.number |= features; + prop->pr_kind = property_number; + } + else if (has_text + && elf_properties (ebfd) == NULL + && elf_tdata (info->output_bfd)->o->build_id.sec == NULL + && !htab->elf.dynamic_sections_created + && !info->traditional_format + && (info->output_bfd->flags & D_PAGED) != 0 + && info->separate_code) + { + /* If the separate code program header is needed, make sure + that the first read-only PT_LOAD segment has no code by + adding a GNU_PROPERTY_X86_ISA_1_NEEDED note. */ + prop = _bfd_elf_get_property (ebfd, + GNU_PROPERTY_X86_ISA_1_NEEDED, + 4); + prop->u.number = GNU_PROPERTY_X86_ISA_1_486; + prop->pr_kind = property_number; + } /* Create the GNU property note section if needed. */ - if (pbfd == NULL) + if (prop != NULL && pbfd == NULL) { sec = bfd_make_section_with_flags (ebfd, NOTE_GNU_PROPERTY_SECTION_NAME, @@ -2411,7 +2622,7 @@ _bfd_x86_elf_link_setup_gnu_properties if (!bfd_set_section_alignment (ebfd, sec, class_align)) { error_alignment: - info->callbacks->einfo (_("%F%A: failed to align section\n"), + info->callbacks->einfo (_("%F%pA: failed to align section\n"), sec); } @@ -2421,12 +2632,6 @@ error_alignment: pbfd = _bfd_elf_link_setup_gnu_properties (info); - bed = get_elf_backend_data (info->output_bfd); - - htab = elf_x86_hash_table (info, bed->target_id); - if (htab == NULL) - return pbfd; - htab->r_info = init_table->r_info; htab->r_sym = init_table->r_sym; @@ -2477,7 +2682,9 @@ error_alignment: abfd = abfd->link.next) if (bfd_get_flavour (abfd) == bfd_target_elf_flavour && (abfd->flags - & (DYNAMIC | BFD_LINKER_CREATED | BFD_PLUGIN)) == 0) + & (DYNAMIC | BFD_LINKER_CREATED | BFD_PLUGIN)) == 0 + && bed->relocs_compatible (abfd->xvec, + info->output_bfd->xvec)) { htab->elf.dynobj = abfd; dynobj = abfd;