1llvm-objcopy - object copying and editing tool 2============================================== 3 4.. program:: llvm-objcopy 5 6SYNOPSIS 7-------- 8 9:program:`llvm-objcopy` [*options*] *input* [*output*] 10 11DESCRIPTION 12----------- 13 14:program:`llvm-objcopy` is a tool to copy and manipulate objects. In basic 15usage, it makes a semantic copy of the input to the output. If any options are 16specified, the output may be modified along the way, e.g. by removing sections. 17 18If no output file is specified, the input file is modified in-place. If "-" is 19specified for the input file, the input is read from the program's standard 20input stream. If "-" is specified for the output file, the output is written to 21the standard output stream of the program. 22 23If the input is an archive, any requested operations will be applied to each 24archive member individually. 25 26The tool is still in active development, but in most scenarios it works as a 27drop-in replacement for GNU's :program:`objcopy`. 28 29GENERIC AND CROSS-PLATFORM OPTIONS 30---------------------------------- 31 32The following options are either agnostic of the file format, or apply to 33multiple file formats. 34 35.. option:: --add-gnu-debuglink <debug-file> 36 37 Add a .gnu_debuglink section for ``<debug-file>`` to the output. 38 39.. option:: --add-section <section=file> 40 41 Add a section named ``<section>`` with the contents of ``<file>`` to the 42 output. For ELF objects the section will be of type `SHT_NOTE`, if the name 43 starts with ".note". Otherwise, it will have type `SHT_PROGBITS`. Can be 44 specified multiple times to add multiple sections. 45 46.. option:: --disable-deterministic-archives, -U 47 48 Use real values for UIDs, GIDs and timestamps when updating archive member 49 headers. 50 51.. option:: --discard-all, -x 52 53 Remove most local symbols from the output. Different file formats may limit 54 this to a subset of the local symbols. For example, file and section symbols in 55 ELF objects will not be discarded. 56 57.. option:: --enable-deterministic-archives, -D 58 59 Enable deterministic mode when copying archives, i.e. use 0 for archive member 60 header UIDs, GIDs and timestamp fields. On by default. 61 62.. option:: --help, -h 63 64 Print a summary of command line options. 65 66.. option:: --only-section <section>, -j 67 68 Remove all sections from the output, except for sections named ``<section>``. 69 Can be specified multiple times to keep multiple sections. 70 71.. option:: --regex 72 73 If specified, symbol and section names specified by other switches are treated 74 as extended POSIX regular expression patterns. 75 76.. option:: --remove-section <section>, -R 77 78 Remove the specified section from the output. Can be specified multiple times 79 to remove multiple sections simultaneously. 80 81.. option:: --strip-all-gnu 82 83 Remove all symbols, debug sections and relocations from the output. This option 84 is equivalent to GNU :program:`objcopy`'s ``--strip-all`` switch. 85 86.. option:: --strip-all, -S 87 88 For ELF objects, remove from the output all symbols and non-alloc sections not 89 within segments, except for .gnu.warning sections and the section name table. 90 91 For COFF objects, remove all symbols, debug sections, and relocations from the 92 output. 93 94.. option:: --strip-debug, -g 95 96 Remove all debug sections from the output. 97 98.. option:: --strip-symbol <symbol>, -N 99 100 Remove all symbols named ``<symbol>`` from the output. Can be specified 101 multiple times to remove multiple symbols. 102 103.. option:: --strip-symbols <filename> 104 105 Remove all symbols whose names appear in the file ``<filename>``, from the 106 output. In the file, each line represents a single symbol name, with leading 107 and trailing whitespace ignored, as is anything following a '#'. Can be 108 specified multiple times to read names from multiple files. 109 110.. option:: --strip-unneeded-symbol <symbol> 111 112 Remove from the output all symbols named ``<symbol>`` that are local or 113 undefined and are not required by any relocation. 114 115.. option:: --strip-unneeded-symbols <filename> 116 117 Remove all symbols whose names appear in the file ``<filename>``, from the 118 output, if they are local or undefined and are not required by any relocation. 119 In the file, each line represents a single symbol name, with leading and 120 trailing whitespace ignored, as is anything following a '#'. Can be specified 121 multiple times to read names from multiple files. 122 123.. option:: --strip-unneeded 124 125 Remove from the output all local or undefined symbols that are not required by 126 relocations. 127 128.. option:: --version, -V 129 130 Display the version of this program. 131 132COFF-SPECIFIC OPTIONS 133--------------------- 134 135The following options are implemented only for COFF objects. If used with other 136objects, :program:`llvm-objcopy` will either emit an error or silently ignore 137them. 138 139.. option:: --only-keep-debug 140 141 Remove the contents of non-debug sections from the output, but keep the section 142 headers. 143 144ELF-SPECIFIC OPTIONS 145-------------------- 146 147The following options are implemented only for ELF objects. If used with other 148objects, :program:`llvm-objcopy` will either emit an error or silently ignore 149them. 150 151.. option:: --add-symbol <name>=[<section>:]<value>[,<flags>] 152 153 Add a new symbol called ``<name>`` to the output symbol table, in the section 154 named ``<section>``, with value ``<value>``. If ``<section>`` is not specified, 155 the symbol is added as an absolute symbol. The ``<flags>`` affect the symbol 156 properties. Accepted values are: 157 158 - `global` = the symbol will have global binding. 159 - `local` = the symbol will have local binding. 160 - `weak` = the symbol will have weak binding. 161 - `default` = the symbol will have default visibility. 162 - `hidden` = the symbol will have hidden visibility. 163 - `protected` = the symbol will have protected visibility. 164 - `file` = the symbol will be an `STT_FILE` symbol. 165 - `section` = the symbol will be an `STT_SECTION` symbol. 166 - `object` = the symbol will be an `STT_OBJECT` symbol. 167 - `function` = the symbol will be an `STT_FUNC` symbol. 168 - `indirect-function` = the symbol will be an `STT_GNU_IFUNC` symbol. 169 170 Additionally, the following flags are accepted but ignored: `debug`, 171 `constructor`, `warning`, `indirect`, `synthetic`, `unique-object`, `before`. 172 173 Can be specified multiple times to add multiple symbols. 174 175.. option:: --allow-broken-links 176 177 Allow llvm-objcopy to remove sections even if it would leave invalid section 178 references. Any invalid sh_link fields will be set to zero. 179 180.. option:: --binary-architecture <arch>, -B 181 182 Specify the architecture to use, when transforming an architecture-less format 183 (e.g. binary) to another format. Valid options are: 184 185 - `aarch64` 186 - `arm` 187 - `i386` 188 - `i386:x86-64` 189 - `mips` 190 - `powerpc:common64` 191 - `riscv:rv32` 192 - `riscv:rv64` 193 - `sparc` 194 - `sparcel` 195 - `x86-64` 196 197.. option:: --build-id-link-dir <dir> 198 199 Set the directory used by :option:`--build-id-link-input` and 200 :option:`--build-id-link-output`. 201 202.. option:: --build-id-link-input <suffix> 203 204 Hard-link the input to ``<dir>/xx/xxx<suffix>``, where ``<dir>`` is the directory 205 specified by :option:`--build-id-link-dir`. The path used is derived from the 206 hex build ID. 207 208.. option:: --build-id-link-output <suffix> 209 210 Hard-link the output to ``<dir>/xx/xxx<suffix>``, where ``<dir>`` is the directory 211 specified by :option:`--build-id-link-dir`. The path used is derived from the 212 hex build ID. 213 214.. option:: --change-start <incr>, --adjust-start 215 216 Add ``<incr>`` to the program's start address. Can be specified multiple 217 times, in which case the values will be applied cumulatively. 218 219.. option:: --compress-debug-sections [<style>] 220 221 Compress DWARF debug sections in the output, using the specified style. 222 Supported styles are `zlib-gnu` and `zlib`. Defaults to `zlib` if no style is 223 specified. 224 225.. option:: --decompress-debug-sections 226 227 Decompress any compressed DWARF debug sections in the output. 228 229.. option:: --discard-locals, -X 230 231 Remove local symbols starting with ".L" from the output. 232 233.. option:: --dump-section <section>=<file> 234 235 Dump the contents of section ``<section>`` into the file ``<file>``. Can be 236 specified multiple times to dump multiple sections to different files. 237 ``<file>`` is unrelated to the input and output files provided to 238 :program:`llvm-objcopy` and as such the normal copying and editing 239 operations will still be performed. No operations are performed on the sections 240 prior to dumping them. 241 242.. option:: --extract-dwo 243 244 Remove all sections that are not DWARF .dwo sections from the output. 245 246.. option:: --extract-main-partition 247 248 Extract the main partition from the output. 249 250.. option:: --extract-partition <name> 251 252 Extract the named partition from the output. 253 254.. option:: --globalize-symbol <symbol> 255 256 Mark any defined symbols named ``<symbol>`` as global symbols in the output. 257 Can be specified multiple times to mark multiple symbols. 258 259.. option:: --globalize-symbols <filename> 260 261 Read a list of names from the file ``<filename>`` and mark defined symbols with 262 those names as global in the output. In the file, each line represents a single 263 symbol, with leading and trailing whitespace ignored, as is anything following 264 a '#'. Can be specified multiple times to read names from multiple files. 265 266.. option:: --input-target <format>, -I 267 268 Read the input as the specified format. See `SUPPORTED FORMATS`_ for a list of 269 valid ``<format>`` values. If unspecified, :program:`llvm-objcopy` will attempt 270 to determine the format automatically. 271 272.. option:: --keep-file-symbols 273 274 Keep symbols of type `STT_FILE`, even if they would otherwise be stripped. 275 276.. option:: --keep-global-symbol <symbol> 277 278 Make all symbols local in the output, except for symbols with the name 279 ``<symbol>``. Can be specified multiple times to ignore multiple symbols. 280 281.. option:: --keep-global-symbols <filename> 282 283 Make all symbols local in the output, except for symbols named in the file 284 ``<filename>``. In the file, each line represents a single symbol, with leading 285 and trailing whitespace ignored, as is anything following a '#'. Can be 286 specified multiple times to read names from multiple files. 287 288.. option:: --keep-section <section> 289 290 When removing sections from the output, do not remove sections named 291 ``<section>``. Can be specified multiple times to keep multiple sections. 292 293.. option:: --keep-symbol <symbol>, -K 294 295 When removing symbols from the output, do not remove symbols named 296 ``<symbol>``. Can be specified multiple times to keep multiple symbols. 297 298.. option:: --keep-symbols <filename> 299 300 When removing symbols from the output do not remove symbols named in the file 301 ``<filename>``. In the file, each line represents a single symbol, with leading 302 and trailing whitespace ignored, as is anything following a '#'. Can be 303 specified multiple times to read names from multiple files. 304 305.. option:: --localize-hidden 306 307 Make all symbols with hidden or internal visibility local in the output. 308 309.. option:: --localize-symbol <symbol>, -L 310 311 Mark any defined non-common symbol named ``<symbol>`` as a local symbol in the 312 output. Can be specified multiple times to mark multiple symbols as local. 313 314.. option:: --localize-symbols <filename> 315 316 Read a list of names from the file ``<filename>`` and mark defined non-common 317 symbols with those names as local in the output. In the file, each line 318 represents a single symbol, with leading and trailing whitespace ignored, as is 319 anything following a '#'. Can be specified multiple times to read names from 320 multiple files. 321 322.. option:: --output-target <format>, -O 323 324 Write the output as the specified format. See `SUPPORTED FORMATS`_ for a list 325 of valid ``<format>`` values. If unspecified, the output format is assumed to 326 be the same as the input file's format. 327 328.. option:: --prefix-alloc-sections <prefix> 329 330 Add ``<prefix>`` to the front of the names of all allocatable sections in the 331 output. 332 333.. option:: --prefix-symbols <prefix> 334 335 Add ``<prefix>`` to the front of every symbol name in the output. 336 337.. option:: --preserve-dates, -p 338 339 Preserve access and modification timestamps in the output. 340 341.. option:: --redefine-sym <old>=<new> 342 343 Rename symbols called ``<old>`` to ``<new>`` in the output. Can be specified 344 multiple times to rename multiple symbols. 345 346.. option:: --redefine-syms <filename> 347 348 Rename symbols in the output as described in the file ``<filename>``. In the 349 file, each line represents a single symbol to rename, with the old name and new 350 name separated by an equals sign. Leading and trailing whitespace is ignored, 351 as is anything following a '#'. Can be specified multiple times to read names 352 from multiple files. 353 354.. option:: --rename-section <old>=<new>[,<flag>,...] 355 356 Rename sections called ``<old>`` to ``<new>`` in the output, and apply any 357 specified ``<flag>`` values. See :option:`--set-section-flags` for a list of 358 supported flags. Can be specified multiple times to rename multiple sections. 359 360.. option:: --set-section-flags <section>=<flag>[,<flag>,...] 361 362 Set section properties in the output of section ``<section>`` based on the 363 specified ``<flag>`` values. Can be specified multiple times to update multiple 364 sections. 365 366 Following is a list of supported flags and their effects: 367 368 - `alloc` = add the `SHF_ALLOC` flag. 369 - `load` = if the section has `SHT_NOBITS` type, mark it as a `SHT_PROGBITS` 370 section. 371 - `readonly` = if this flag is not specified, add the `SHF_WRITE` flag. 372 - `code` = add the `SHF_EXECINSTR` flag. 373 - `merge` = add the `SHF_MERGE` flag. 374 - `strings` = add the `SHF_STRINGS` flag. 375 - `contents` = if the section has `SHT_NOBITS` type, mark it as a `SHT_PROGBITS` 376 section. 377 378 The following flags are also accepted, but are ignored for GNU compatibility: 379 `noload`, `debug`, `data`, `rom`, `share`. 380 381.. option:: --set-start-addr <addr> 382 383 Set the start address of the output to ``<addr>``. Overrides any previously 384 specified :option:`--change-start` or :option:`--adjust-start` options. 385 386.. option:: --split-dwo <dwo-file> 387 388 Equivalent to running :program:`llvm-objcopy` with :option:`--extract-dwo` and 389 ``<dwo-file>`` as the output file and no other options, and then with 390 :option:`--strip-dwo` on the input file. 391 392.. option:: --strip-dwo 393 394 Remove all DWARF .dwo sections from the output. 395 396.. option:: --strip-non-alloc 397 398 Remove from the output all non-allocatable sections that are not within 399 segments. 400 401.. option:: --strip-sections 402 403 Remove from the output all section headers and all section data not within 404 segments. Note that many tools will not be able to use an object without 405 section headers. 406 407.. option:: --target <format>, -F 408 409 Equivalent to :option:`--input-target` and :option:`--output-target` for the 410 specified format. See `SUPPORTED FORMATS`_ for a list of valid ``<format>`` 411 values. 412 413.. option:: --weaken-symbol <symbol>, -W 414 415 Mark any global symbol named ``<symbol>`` as a weak symbol in the output. Can 416 be specified multiple times to mark multiple symbols as weak. 417 418.. option:: --weaken-symbols <filename> 419 420 Read a list of names from the file ``<filename>`` and mark global symbols with 421 those names as weak in the output. In the file, each line represents a single 422 symbol, with leading and trailing whitespace ignored, as is anything following 423 a '#'. Can be specified multiple times to read names from multiple files. 424 425.. option:: --weaken 426 427 Mark all defined global symbols as weak in the output. 428 429SUPPORTED FORMATS 430----------------- 431 432The following values are currently supported by :program:`llvm-objcopy` for the 433:option:`--input-target`, :option:`--output-target`, and :option:`--target` 434options. For GNU :program:`objcopy` compatibility, the values are all bfdnames. 435 436- `binary` 437- `ihex` 438- `elf32-i386` 439- `elf32-x86-64` 440- `elf64-x86-64` 441- `elf32-iamcu` 442- `elf32-littlearm` 443- `elf64-aarch64` 444- `elf64-littleaarch64` 445- `elf32-littleriscv` 446- `elf64-littleriscv` 447- `elf32-powerpc` 448- `elf32-powerpcle` 449- `elf64-powerpc` 450- `elf64-powerpcle` 451- `elf32-bigmips` 452- `elf32-ntradbigmips` 453- `elf32-ntradlittlemips` 454- `elf32-tradbigmips` 455- `elf32-tradlittlemips` 456- `elf64-tradbigmips` 457- `elf64-tradlittlemips` 458- `elf32-sparc` 459- `elf32-sparcel` 460 461Additionally, all targets except `binary` and `ihex` can have `-freebsd` as a 462suffix. 463 464BINARY INPUT AND OUTPUT 465----------------------- 466 467If `binary` is used as the value for :option:`--input-target`, the input file 468will be embedded as a data section in an ELF relocatable object, with symbols 469``_binary_<file_name>_start``, ``_binary_<file_name>_end``, and 470``_binary_<file_name>_size`` representing the start, end and size of the data, 471where ``<file_name>`` is the path of the input file as specified on the command 472line with non-alphanumeric characters converted to ``_``. 473 474If `binary` is used as the value for :option:`--output-target`, the output file 475will be a raw binary file, containing the memory image of the input file. 476Symbols and relocation information will be discarded. The image will start at 477the address of the first loadable section in the output. 478 479EXIT STATUS 480----------- 481 482:program:`llvm-objcopy` exits with a non-zero exit code if there is an error. 483Otherwise, it exits with code 0. 484 485BUGS 486---- 487 488To report bugs, please visit <http://llvm.org/bugs/>. 489 490There is a known issue with :option:`--input-target` and :option:`--target` 491causing only ``binary`` and ``ihex`` formats to have any effect. Other values 492will be ignored and :program:`llvm-objcopy` will attempt to guess the input 493format. 494 495SEE ALSO 496-------- 497 498:manpage:`llvm-strip(1)` 499