mirror of
https://github.com/bminor/binutils-gdb.git
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bfd: aarch64: Refactor stub sizing code
elfNN_aarch64_size_stubs has grown big, so factor out the call stub related code before adding new logic there.
This commit is contained in:
Szabolcs Nagy
@@ -4265,12 +4265,285 @@ _bfd_aarch64_erratum_843419_scan (bfd *input_bfd, asection *section,
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}
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/* Determine and set the size of the stub section for a final link.
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/* Add stub entries for calls.
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The basic idea here is to examine all the relocations looking for
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PC-relative calls to a target that is unreachable with a "bl"
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instruction. */
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static bool
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_bfd_aarch64_add_call_stub_entries (bool *stub_changed, bfd *output_bfd,
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struct bfd_link_info *info)
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{
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struct elf_aarch64_link_hash_table *htab = elf_aarch64_hash_table (info);
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bfd *input_bfd;
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for (input_bfd = info->input_bfds; input_bfd != NULL;
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input_bfd = input_bfd->link.next)
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{
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Elf_Internal_Shdr *symtab_hdr;
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asection *section;
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Elf_Internal_Sym *local_syms = NULL;
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if (!is_aarch64_elf (input_bfd)
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|| (input_bfd->flags & BFD_LINKER_CREATED) != 0)
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continue;
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/* We'll need the symbol table in a second. */
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symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr;
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if (symtab_hdr->sh_info == 0)
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continue;
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/* Walk over each section attached to the input bfd. */
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for (section = input_bfd->sections;
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section != NULL; section = section->next)
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{
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Elf_Internal_Rela *internal_relocs, *irelaend, *irela;
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/* If there aren't any relocs, then there's nothing more to do. */
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if ((section->flags & SEC_RELOC) == 0
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|| section->reloc_count == 0
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|| (section->flags & SEC_CODE) == 0)
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continue;
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/* If this section is a link-once section that will be
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discarded, then don't create any stubs. */
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if (section->output_section == NULL
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|| section->output_section->owner != output_bfd)
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continue;
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/* Get the relocs. */
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internal_relocs
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= _bfd_elf_link_read_relocs (input_bfd, section, NULL,
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NULL, info->keep_memory);
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if (internal_relocs == NULL)
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goto error_ret_free_local;
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/* Now examine each relocation. */
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irela = internal_relocs;
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irelaend = irela + section->reloc_count;
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for (; irela < irelaend; irela++)
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{
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unsigned int r_type, r_indx;
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enum elf_aarch64_stub_type stub_type;
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struct elf_aarch64_stub_hash_entry *stub_entry;
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asection *sym_sec;
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bfd_vma sym_value;
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bfd_vma destination;
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struct elf_aarch64_link_hash_entry *hash;
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const char *sym_name;
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char *stub_name;
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const asection *id_sec;
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unsigned char st_type;
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bfd_size_type len;
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r_type = ELFNN_R_TYPE (irela->r_info);
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r_indx = ELFNN_R_SYM (irela->r_info);
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if (r_type >= (unsigned int) R_AARCH64_end)
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{
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bfd_set_error (bfd_error_bad_value);
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error_ret_free_internal:
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if (elf_section_data (section)->relocs == NULL)
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free (internal_relocs);
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goto error_ret_free_local;
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}
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/* Only look for stubs on unconditional branch and
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branch and link instructions. */
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if (r_type != (unsigned int) AARCH64_R (CALL26)
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&& r_type != (unsigned int) AARCH64_R (JUMP26))
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continue;
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/* Now determine the call target, its name, value,
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section. */
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sym_sec = NULL;
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sym_value = 0;
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destination = 0;
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hash = NULL;
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sym_name = NULL;
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if (r_indx < symtab_hdr->sh_info)
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{
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/* It's a local symbol. */
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Elf_Internal_Sym *sym;
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Elf_Internal_Shdr *hdr;
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if (local_syms == NULL)
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{
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local_syms
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= (Elf_Internal_Sym *) symtab_hdr->contents;
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if (local_syms == NULL)
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local_syms
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= bfd_elf_get_elf_syms (input_bfd, symtab_hdr,
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symtab_hdr->sh_info, 0,
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NULL, NULL, NULL);
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if (local_syms == NULL)
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goto error_ret_free_internal;
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}
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sym = local_syms + r_indx;
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hdr = elf_elfsections (input_bfd)[sym->st_shndx];
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sym_sec = hdr->bfd_section;
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if (!sym_sec)
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/* This is an undefined symbol. It can never
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be resolved. */
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continue;
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if (ELF_ST_TYPE (sym->st_info) != STT_SECTION)
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sym_value = sym->st_value;
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destination = (sym_value + irela->r_addend
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+ sym_sec->output_offset
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+ sym_sec->output_section->vma);
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st_type = ELF_ST_TYPE (sym->st_info);
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sym_name
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= bfd_elf_string_from_elf_section (input_bfd,
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symtab_hdr->sh_link,
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sym->st_name);
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}
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else
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{
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int e_indx;
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e_indx = r_indx - symtab_hdr->sh_info;
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hash = ((struct elf_aarch64_link_hash_entry *)
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elf_sym_hashes (input_bfd)[e_indx]);
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while (hash->root.root.type == bfd_link_hash_indirect
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|| hash->root.root.type == bfd_link_hash_warning)
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hash = ((struct elf_aarch64_link_hash_entry *)
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hash->root.root.u.i.link);
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if (hash->root.root.type == bfd_link_hash_defined
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|| hash->root.root.type == bfd_link_hash_defweak)
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{
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struct elf_aarch64_link_hash_table *globals =
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elf_aarch64_hash_table (info);
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sym_sec = hash->root.root.u.def.section;
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sym_value = hash->root.root.u.def.value;
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/* For a destination in a shared library,
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use the PLT stub as target address to
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decide whether a branch stub is
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needed. */
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if (globals->root.splt != NULL && hash != NULL
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&& hash->root.plt.offset != (bfd_vma) - 1)
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{
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sym_sec = globals->root.splt;
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sym_value = hash->root.plt.offset;
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if (sym_sec->output_section != NULL)
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destination = (sym_value
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+ sym_sec->output_offset
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+ sym_sec->output_section->vma);
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}
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else if (sym_sec->output_section != NULL)
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destination = (sym_value + irela->r_addend
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+ sym_sec->output_offset
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+ sym_sec->output_section->vma);
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}
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else if (hash->root.root.type == bfd_link_hash_undefined
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|| (hash->root.root.type
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== bfd_link_hash_undefweak))
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{
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/* For a shared library, use the PLT stub as
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target address to decide whether a long
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branch stub is needed.
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For absolute code, they cannot be handled. */
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struct elf_aarch64_link_hash_table *globals =
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elf_aarch64_hash_table (info);
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if (globals->root.splt != NULL && hash != NULL
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&& hash->root.plt.offset != (bfd_vma) - 1)
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{
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sym_sec = globals->root.splt;
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sym_value = hash->root.plt.offset;
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if (sym_sec->output_section != NULL)
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destination = (sym_value
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+ sym_sec->output_offset
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+ sym_sec->output_section->vma);
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}
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else
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continue;
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}
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else
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{
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bfd_set_error (bfd_error_bad_value);
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goto error_ret_free_internal;
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}
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st_type = ELF_ST_TYPE (hash->root.type);
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sym_name = hash->root.root.root.string;
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}
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/* Determine what (if any) linker stub is needed. */
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stub_type = aarch64_type_of_stub (section, irela, sym_sec,
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st_type, destination);
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if (stub_type == aarch64_stub_none)
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continue;
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/* Support for grouping stub sections. */
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id_sec = htab->stub_group[section->id].link_sec;
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/* Get the name of this stub. */
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stub_name = elfNN_aarch64_stub_name (id_sec, sym_sec, hash,
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irela);
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if (!stub_name)
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goto error_ret_free_internal;
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stub_entry =
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aarch64_stub_hash_lookup (&htab->stub_hash_table,
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stub_name, false, false);
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if (stub_entry != NULL)
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{
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/* The proper stub has already been created. */
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free (stub_name);
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/* Always update this stub's target since it may have
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changed after layout. */
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stub_entry->target_value = sym_value + irela->r_addend;
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continue;
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}
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stub_entry = _bfd_aarch64_add_stub_entry_in_group
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(stub_name, section, htab);
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if (stub_entry == NULL)
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{
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free (stub_name);
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goto error_ret_free_internal;
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}
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stub_entry->target_value = sym_value + irela->r_addend;
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stub_entry->target_section = sym_sec;
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stub_entry->stub_type = stub_type;
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stub_entry->h = hash;
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stub_entry->st_type = st_type;
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if (sym_name == NULL)
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sym_name = "unnamed";
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len = sizeof (STUB_ENTRY_NAME) + strlen (sym_name);
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stub_entry->output_name = bfd_alloc (htab->stub_bfd, len);
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if (stub_entry->output_name == NULL)
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{
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free (stub_name);
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goto error_ret_free_internal;
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}
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snprintf (stub_entry->output_name, len, STUB_ENTRY_NAME,
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sym_name);
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*stub_changed = true;
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}
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/* We're done with the internal relocs, free them. */
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if (elf_section_data (section)->relocs == NULL)
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free (internal_relocs);
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}
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}
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return true;
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error_ret_free_local:
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return false;
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}
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/* Determine and set the size of the stub section for a final link. */
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bool
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elfNN_aarch64_size_stubs (bfd *output_bfd,
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bfd *stub_bfd,
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@@ -4282,7 +4555,6 @@ elfNN_aarch64_size_stubs (bfd *output_bfd,
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{
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bfd_size_type stub_group_size;
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bool stubs_always_before_branch;
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bool stub_changed = false;
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struct elf_aarch64_link_hash_table *htab = elf_aarch64_hash_table (info);
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unsigned int num_erratum_835769_fixes = 0;
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@@ -4357,285 +4629,19 @@ elfNN_aarch64_size_stubs (bfd *output_bfd,
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(*htab->layout_sections_again) ();
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}
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while (1)
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for (;;)
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{
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bfd *input_bfd;
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bool stub_changed = false;
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for (input_bfd = info->input_bfds;
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input_bfd != NULL; input_bfd = input_bfd->link.next)
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{
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Elf_Internal_Shdr *symtab_hdr;
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asection *section;
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Elf_Internal_Sym *local_syms = NULL;
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if (!is_aarch64_elf (input_bfd)
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|| (input_bfd->flags & BFD_LINKER_CREATED) != 0)
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continue;
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/* We'll need the symbol table in a second. */
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symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr;
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if (symtab_hdr->sh_info == 0)
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continue;
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/* Walk over each section attached to the input bfd. */
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for (section = input_bfd->sections;
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section != NULL; section = section->next)
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{
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Elf_Internal_Rela *internal_relocs, *irelaend, *irela;
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/* If there aren't any relocs, then there's nothing more
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to do. */
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if ((section->flags & SEC_RELOC) == 0
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|| section->reloc_count == 0
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|| (section->flags & SEC_CODE) == 0)
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continue;
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/* If this section is a link-once section that will be
|
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discarded, then don't create any stubs. */
|
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if (section->output_section == NULL
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|| section->output_section->owner != output_bfd)
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continue;
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/* Get the relocs. */
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internal_relocs
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= _bfd_elf_link_read_relocs (input_bfd, section, NULL,
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NULL, info->keep_memory);
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if (internal_relocs == NULL)
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goto error_ret_free_local;
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/* Now examine each relocation. */
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irela = internal_relocs;
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irelaend = irela + section->reloc_count;
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for (; irela < irelaend; irela++)
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{
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unsigned int r_type, r_indx;
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enum elf_aarch64_stub_type stub_type;
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struct elf_aarch64_stub_hash_entry *stub_entry;
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asection *sym_sec;
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bfd_vma sym_value;
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bfd_vma destination;
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struct elf_aarch64_link_hash_entry *hash;
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const char *sym_name;
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char *stub_name;
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const asection *id_sec;
|
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unsigned char st_type;
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bfd_size_type len;
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r_type = ELFNN_R_TYPE (irela->r_info);
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r_indx = ELFNN_R_SYM (irela->r_info);
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|
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if (r_type >= (unsigned int) R_AARCH64_end)
|
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{
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bfd_set_error (bfd_error_bad_value);
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error_ret_free_internal:
|
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if (elf_section_data (section)->relocs == NULL)
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free (internal_relocs);
|
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goto error_ret_free_local;
|
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}
|
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|
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/* Only look for stubs on unconditional branch and
|
||||
branch and link instructions. */
|
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if (r_type != (unsigned int) AARCH64_R (CALL26)
|
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&& r_type != (unsigned int) AARCH64_R (JUMP26))
|
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continue;
|
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|
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/* Now determine the call target, its name, value,
|
||||
section. */
|
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sym_sec = NULL;
|
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sym_value = 0;
|
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destination = 0;
|
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hash = NULL;
|
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sym_name = NULL;
|
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if (r_indx < symtab_hdr->sh_info)
|
||||
{
|
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/* It's a local symbol. */
|
||||
Elf_Internal_Sym *sym;
|
||||
Elf_Internal_Shdr *hdr;
|
||||
|
||||
if (local_syms == NULL)
|
||||
{
|
||||
local_syms
|
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= (Elf_Internal_Sym *) symtab_hdr->contents;
|
||||
if (local_syms == NULL)
|
||||
local_syms
|
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= bfd_elf_get_elf_syms (input_bfd, symtab_hdr,
|
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symtab_hdr->sh_info, 0,
|
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NULL, NULL, NULL);
|
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if (local_syms == NULL)
|
||||
goto error_ret_free_internal;
|
||||
}
|
||||
|
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sym = local_syms + r_indx;
|
||||
hdr = elf_elfsections (input_bfd)[sym->st_shndx];
|
||||
sym_sec = hdr->bfd_section;
|
||||
if (!sym_sec)
|
||||
/* This is an undefined symbol. It can never
|
||||
be resolved. */
|
||||
continue;
|
||||
|
||||
if (ELF_ST_TYPE (sym->st_info) != STT_SECTION)
|
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sym_value = sym->st_value;
|
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destination = (sym_value + irela->r_addend
|
||||
+ sym_sec->output_offset
|
||||
+ sym_sec->output_section->vma);
|
||||
st_type = ELF_ST_TYPE (sym->st_info);
|
||||
sym_name
|
||||
= bfd_elf_string_from_elf_section (input_bfd,
|
||||
symtab_hdr->sh_link,
|
||||
sym->st_name);
|
||||
}
|
||||
else
|
||||
{
|
||||
int e_indx;
|
||||
|
||||
e_indx = r_indx - symtab_hdr->sh_info;
|
||||
hash = ((struct elf_aarch64_link_hash_entry *)
|
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elf_sym_hashes (input_bfd)[e_indx]);
|
||||
|
||||
while (hash->root.root.type == bfd_link_hash_indirect
|
||||
|| hash->root.root.type == bfd_link_hash_warning)
|
||||
hash = ((struct elf_aarch64_link_hash_entry *)
|
||||
hash->root.root.u.i.link);
|
||||
|
||||
if (hash->root.root.type == bfd_link_hash_defined
|
||||
|| hash->root.root.type == bfd_link_hash_defweak)
|
||||
{
|
||||
struct elf_aarch64_link_hash_table *globals =
|
||||
elf_aarch64_hash_table (info);
|
||||
sym_sec = hash->root.root.u.def.section;
|
||||
sym_value = hash->root.root.u.def.value;
|
||||
/* For a destination in a shared library,
|
||||
use the PLT stub as target address to
|
||||
decide whether a branch stub is
|
||||
needed. */
|
||||
if (globals->root.splt != NULL && hash != NULL
|
||||
&& hash->root.plt.offset != (bfd_vma) - 1)
|
||||
{
|
||||
sym_sec = globals->root.splt;
|
||||
sym_value = hash->root.plt.offset;
|
||||
if (sym_sec->output_section != NULL)
|
||||
destination = (sym_value
|
||||
+ sym_sec->output_offset
|
||||
+
|
||||
sym_sec->output_section->vma);
|
||||
}
|
||||
else if (sym_sec->output_section != NULL)
|
||||
destination = (sym_value + irela->r_addend
|
||||
+ sym_sec->output_offset
|
||||
+ sym_sec->output_section->vma);
|
||||
}
|
||||
else if (hash->root.root.type == bfd_link_hash_undefined
|
||||
|| (hash->root.root.type
|
||||
== bfd_link_hash_undefweak))
|
||||
{
|
||||
/* For a shared library, use the PLT stub as
|
||||
target address to decide whether a long
|
||||
branch stub is needed.
|
||||
For absolute code, they cannot be handled. */
|
||||
struct elf_aarch64_link_hash_table *globals =
|
||||
elf_aarch64_hash_table (info);
|
||||
|
||||
if (globals->root.splt != NULL && hash != NULL
|
||||
&& hash->root.plt.offset != (bfd_vma) - 1)
|
||||
{
|
||||
sym_sec = globals->root.splt;
|
||||
sym_value = hash->root.plt.offset;
|
||||
if (sym_sec->output_section != NULL)
|
||||
destination = (sym_value
|
||||
+ sym_sec->output_offset
|
||||
+
|
||||
sym_sec->output_section->vma);
|
||||
}
|
||||
else
|
||||
continue;
|
||||
}
|
||||
else
|
||||
{
|
||||
bfd_set_error (bfd_error_bad_value);
|
||||
goto error_ret_free_internal;
|
||||
}
|
||||
st_type = ELF_ST_TYPE (hash->root.type);
|
||||
sym_name = hash->root.root.root.string;
|
||||
}
|
||||
|
||||
/* Determine what (if any) linker stub is needed. */
|
||||
stub_type = aarch64_type_of_stub (section, irela, sym_sec,
|
||||
st_type, destination);
|
||||
if (stub_type == aarch64_stub_none)
|
||||
continue;
|
||||
|
||||
/* Support for grouping stub sections. */
|
||||
id_sec = htab->stub_group[section->id].link_sec;
|
||||
|
||||
/* Get the name of this stub. */
|
||||
stub_name = elfNN_aarch64_stub_name (id_sec, sym_sec, hash,
|
||||
irela);
|
||||
if (!stub_name)
|
||||
goto error_ret_free_internal;
|
||||
|
||||
stub_entry =
|
||||
aarch64_stub_hash_lookup (&htab->stub_hash_table,
|
||||
stub_name, false, false);
|
||||
if (stub_entry != NULL)
|
||||
{
|
||||
/* The proper stub has already been created. */
|
||||
free (stub_name);
|
||||
/* Always update this stub's target since it may have
|
||||
changed after layout. */
|
||||
stub_entry->target_value = sym_value + irela->r_addend;
|
||||
continue;
|
||||
}
|
||||
|
||||
stub_entry = _bfd_aarch64_add_stub_entry_in_group
|
||||
(stub_name, section, htab);
|
||||
if (stub_entry == NULL)
|
||||
{
|
||||
free (stub_name);
|
||||
goto error_ret_free_internal;
|
||||
}
|
||||
|
||||
stub_entry->target_value = sym_value + irela->r_addend;
|
||||
stub_entry->target_section = sym_sec;
|
||||
stub_entry->stub_type = stub_type;
|
||||
stub_entry->h = hash;
|
||||
stub_entry->st_type = st_type;
|
||||
|
||||
if (sym_name == NULL)
|
||||
sym_name = "unnamed";
|
||||
len = sizeof (STUB_ENTRY_NAME) + strlen (sym_name);
|
||||
stub_entry->output_name = bfd_alloc (htab->stub_bfd, len);
|
||||
if (stub_entry->output_name == NULL)
|
||||
{
|
||||
free (stub_name);
|
||||
goto error_ret_free_internal;
|
||||
}
|
||||
|
||||
snprintf (stub_entry->output_name, len, STUB_ENTRY_NAME,
|
||||
sym_name);
|
||||
|
||||
stub_changed = true;
|
||||
}
|
||||
|
||||
/* We're done with the internal relocs, free them. */
|
||||
if (elf_section_data (section)->relocs == NULL)
|
||||
free (internal_relocs);
|
||||
}
|
||||
}
|
||||
if (!_bfd_aarch64_add_call_stub_entries (&stub_changed, output_bfd, info))
|
||||
return false;
|
||||
|
||||
if (!stub_changed)
|
||||
break;
|
||||
return true;
|
||||
|
||||
_bfd_aarch64_resize_stubs (htab);
|
||||
|
||||
/* Ask the linker to do its stuff. */
|
||||
(*htab->layout_sections_again) ();
|
||||
stub_changed = false;
|
||||
}
|
||||
|
||||
return true;
|
||||
|
||||
error_ret_free_local:
|
||||
return false;
|
||||
}
|
||||
|
||||
/* Build all the stubs associated with the current output file. The
|
||||
|
||||
Reference in New Issue
Block a user