| 1 | /* Emulation code used by all ELF targets. |
| 2 | Copyright (C) 1991-2020 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of the GNU Binutils. |
| 5 | |
| 6 | This program is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 3 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | This program is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with this program; if not, write to the Free Software |
| 18 | Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| 19 | MA 02110-1301, USA. */ |
| 20 | |
| 21 | #include "sysdep.h" |
| 22 | #include "bfd.h" |
| 23 | #include "bfdlink.h" |
| 24 | #include "ctf-api.h" |
| 25 | #include "ld.h" |
| 26 | #include "ldmain.h" |
| 27 | #include "ldmisc.h" |
| 28 | #include "ldexp.h" |
| 29 | #include "ldlang.h" |
| 30 | #include "elf-bfd.h" |
| 31 | #include "ldelfgen.h" |
| 32 | |
| 33 | void |
| 34 | ldelf_map_segments (bfd_boolean need_layout) |
| 35 | { |
| 36 | int tries = 10; |
| 37 | |
| 38 | do |
| 39 | { |
| 40 | lang_relax_sections (need_layout); |
| 41 | need_layout = FALSE; |
| 42 | |
| 43 | if (link_info.output_bfd->xvec->flavour == bfd_target_elf_flavour |
| 44 | && !bfd_link_relocatable (&link_info)) |
| 45 | { |
| 46 | bfd_size_type phdr_size; |
| 47 | |
| 48 | phdr_size = elf_program_header_size (link_info.output_bfd); |
| 49 | /* If we don't have user supplied phdrs, throw away any |
| 50 | previous linker generated program headers. */ |
| 51 | if (lang_phdr_list == NULL) |
| 52 | elf_seg_map (link_info.output_bfd) = NULL; |
| 53 | if (!_bfd_elf_map_sections_to_segments (link_info.output_bfd, |
| 54 | &link_info)) |
| 55 | einfo (_("%F%P: map sections to segments failed: %E\n")); |
| 56 | |
| 57 | if (phdr_size != elf_program_header_size (link_info.output_bfd)) |
| 58 | { |
| 59 | if (tries > 6) |
| 60 | /* The first few times we allow any change to |
| 61 | phdr_size . */ |
| 62 | need_layout = TRUE; |
| 63 | else if (phdr_size |
| 64 | < elf_program_header_size (link_info.output_bfd)) |
| 65 | /* After that we only allow the size to grow. */ |
| 66 | need_layout = TRUE; |
| 67 | else |
| 68 | elf_program_header_size (link_info.output_bfd) = phdr_size; |
| 69 | } |
| 70 | } |
| 71 | } |
| 72 | while (need_layout && --tries); |
| 73 | |
| 74 | if (tries == 0) |
| 75 | einfo (_("%F%P: looping in map_segments")); |
| 76 | } |
| 77 | |
| 78 | /* We want to emit CTF early if and only if we are not targetting ELF with this |
| 79 | invocation. */ |
| 80 | |
| 81 | int |
| 82 | ldelf_emit_ctf_early (void) |
| 83 | { |
| 84 | if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour) |
| 85 | return 0; |
| 86 | return 1; |
| 87 | } |
| 88 | |
| 89 | /* Callbacks used to map from bfd types to libctf types, under libctf's |
| 90 | control. */ |
| 91 | |
| 92 | struct ctf_strsym_iter_cb_arg |
| 93 | { |
| 94 | struct elf_sym_strtab *syms; |
| 95 | bfd_size_type symcount; |
| 96 | struct elf_strtab_hash *symstrtab; |
| 97 | size_t next_i; |
| 98 | size_t next_idx; |
| 99 | }; |
| 100 | |
| 101 | /* Return strings from the strtab to libctf, one by one. Returns NULL when |
| 102 | iteration is complete. */ |
| 103 | |
| 104 | static const char * |
| 105 | ldelf_ctf_strtab_iter_cb (uint32_t *offset, void *arg_) |
| 106 | { |
| 107 | bfd_size_type off; |
| 108 | const char *ret; |
| 109 | |
| 110 | struct ctf_strsym_iter_cb_arg *arg = |
| 111 | (struct ctf_strsym_iter_cb_arg *) arg_; |
| 112 | |
| 113 | /* There is no zeroth string. */ |
| 114 | if (arg->next_i == 0) |
| 115 | arg->next_i = 1; |
| 116 | |
| 117 | if (arg->next_i >= _bfd_elf_strtab_len (arg->symstrtab)) |
| 118 | { |
| 119 | arg->next_i = 0; |
| 120 | return NULL; |
| 121 | } |
| 122 | |
| 123 | ret = _bfd_elf_strtab_str (arg->symstrtab, arg->next_i++, &off); |
| 124 | *offset = off; |
| 125 | |
| 126 | /* If we've overflowed, we cannot share any further strings: the CTF |
| 127 | format cannot encode strings with such high offsets. */ |
| 128 | if (*offset != off) |
| 129 | return NULL; |
| 130 | |
| 131 | return ret; |
| 132 | } |
| 133 | |
| 134 | /* Return symbols from the symbol table to libctf, one by one. We assume (and |
| 135 | assert) that the symbols in the elf_link_hash_table are in strictly ascending |
| 136 | order, and that none will be added in between existing ones. Returns NULL |
| 137 | when iteration is complete. */ |
| 138 | |
| 139 | static struct ctf_link_sym * |
| 140 | ldelf_ctf_symbols_iter_cb (struct ctf_link_sym *dest, |
| 141 | void *arg_) |
| 142 | { |
| 143 | struct ctf_strsym_iter_cb_arg *arg = |
| 144 | (struct ctf_strsym_iter_cb_arg *) arg_; |
| 145 | |
| 146 | if (arg->next_i > arg->symcount) |
| 147 | { |
| 148 | arg->next_i = 0; |
| 149 | arg->next_idx = 0; |
| 150 | return NULL; |
| 151 | } |
| 152 | |
| 153 | ASSERT (arg->syms[arg->next_i].dest_index == arg->next_idx); |
| 154 | dest->st_name = _bfd_elf_strtab_str (arg->symstrtab, arg->next_i, NULL); |
| 155 | dest->st_shndx = arg->syms[arg->next_i].sym.st_shndx; |
| 156 | dest->st_type = ELF_ST_TYPE (arg->syms[arg->next_i].sym.st_info); |
| 157 | dest->st_value = arg->syms[arg->next_i].sym.st_value; |
| 158 | arg->next_i++; |
| 159 | return dest; |
| 160 | } |
| 161 | |
| 162 | void |
| 163 | ldelf_examine_strtab_for_ctf |
| 164 | (struct ctf_file *ctf_output, struct elf_sym_strtab *syms, |
| 165 | bfd_size_type symcount, struct elf_strtab_hash *symstrtab) |
| 166 | { |
| 167 | struct ctf_strsym_iter_cb_arg args = { syms, symcount, symstrtab, |
| 168 | 0, 0 }; |
| 169 | if (!ctf_output) |
| 170 | return; |
| 171 | |
| 172 | if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour |
| 173 | && !bfd_link_relocatable (&link_info)) |
| 174 | { |
| 175 | if (ctf_link_add_strtab (ctf_output, ldelf_ctf_strtab_iter_cb, |
| 176 | &args) < 0) |
| 177 | einfo (_("%F%P: warning: CTF strtab association failed; strings will " |
| 178 | "not be shared: %s\n"), |
| 179 | ctf_errmsg (ctf_errno (ctf_output))); |
| 180 | |
| 181 | if (ctf_link_shuffle_syms (ctf_output, ldelf_ctf_symbols_iter_cb, |
| 182 | &args) < 0) |
| 183 | einfo (_("%F%P: warning: CTF symbol shuffling failed; slight space " |
| 184 | "cost: %s\n"), ctf_errmsg (ctf_errno (ctf_output))); |
| 185 | } |
| 186 | } |