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 For MachO objects, ``<section>`` must be formatted as 47 ``<segment name>,<section name>``. 48 49.. option:: --binary-architecture <arch>, -B 50 51 Ignored for compatibility. 52 53.. option:: --disable-deterministic-archives, -U 54 55 Use real values for UIDs, GIDs and timestamps when updating archive member 56 headers. 57 58.. option:: --discard-all, -x 59 60 Remove most local symbols from the output. Different file formats may limit 61 this to a subset of the local symbols. For example, file and section symbols in 62 ELF objects will not be discarded. 63 64.. option:: --dump-section <section>=<file> 65 66 Dump the contents of section ``<section>`` into the file ``<file>``. Can be 67 specified multiple times to dump multiple sections to different files. 68 ``<file>`` is unrelated to the input and output files provided to 69 :program:`llvm-objcopy` and as such the normal copying and editing 70 operations will still be performed. No operations are performed on the sections 71 prior to dumping them. 72 73 For MachO objects, ``<section>`` must be formatted as 74 ``<segment name>,<section name>``. 75 76.. option:: --enable-deterministic-archives, -D 77 78 Enable deterministic mode when copying archives, i.e. use 0 for archive member 79 header UIDs, GIDs and timestamp fields. On by default. 80 81.. option:: --help, -h 82 83 Print a summary of command line options. 84 85.. option:: --only-keep-debug 86 87 Produce a debug file as the output that only preserves contents of sections 88 useful for debugging purposes. 89 90 For ELF objects, this removes the contents of `SHF_ALLOC` sections that are not 91 `SHT_NOTE` by making them `SHT_NOBITS` and shrinking the program headers where 92 possible. 93 94.. option:: --only-section <section>, -j 95 96 Remove all sections from the output, except for sections named ``<section>``. 97 Can be specified multiple times to keep multiple sections. 98 99 For MachO objects, ``<section>`` must be formatted as 100 ``<segment name>,<section name>``. 101 102.. option:: --redefine-sym <old>=<new> 103 104 Rename symbols called ``<old>`` to ``<new>`` in the output. Can be specified 105 multiple times to rename multiple symbols. 106 107.. option:: --redefine-syms <filename> 108 109 Rename symbols in the output as described in the file ``<filename>``. In the 110 file, each line represents a single symbol to rename, with the old name and new 111 name separated by whitespace. Leading and trailing whitespace is ignored, as is 112 anything following a '#'. Can be specified multiple times to read names from 113 multiple files. 114 115.. option:: --regex 116 117 If specified, symbol and section names specified by other switches are treated 118 as extended POSIX regular expression patterns. 119 120.. option:: --remove-section <section>, -R 121 122 Remove the specified section from the output. Can be specified multiple times 123 to remove multiple sections simultaneously. 124 125 For MachO objects, ``<section>`` must be formatted as 126 ``<segment name>,<section name>``. 127 128.. option:: --set-section-alignment <section>=<align> 129 130 Set the alignment of section ``<section>`` to `<align>``. Can be specified 131 multiple times to update multiple sections. 132 133.. option:: --set-section-flags <section>=<flag>[,<flag>,...] 134 135 Set section properties in the output of section ``<section>`` based on the 136 specified ``<flag>`` values. Can be specified multiple times to update multiple 137 sections. 138 139 Supported flag names are `alloc`, `load`, `noload`, `readonly`, `exclude`, 140 `debug`, `code`, `data`, `rom`, `share`, `contents`, `merge` and `strings`. Not 141 all flags are meaningful for all object file formats. 142 143 For ELF objects, the flags have the following effects: 144 145 - `alloc` = add the `SHF_ALLOC` flag. 146 - `load` = if the section has `SHT_NOBITS` type, mark it as a `SHT_PROGBITS` 147 section. 148 - `readonly` = if this flag is not specified, add the `SHF_WRITE` flag. 149 - `exclude` = add the `SHF_EXCLUDE` flag. 150 - `code` = add the `SHF_EXECINSTR` flag. 151 - `merge` = add the `SHF_MERGE` flag. 152 - `strings` = add the `SHF_STRINGS` flag. 153 - `contents` = if the section has `SHT_NOBITS` type, mark it as a `SHT_PROGBITS` 154 section. 155 156 For COFF objects, the flags have the following effects: 157 158 - `alloc` = add the `IMAGE_SCN_CNT_UNINITIALIZED_DATA` and `IMAGE_SCN_MEM_READ` 159 flags, unless the `load` flag is specified. 160 - `noload` = add the `IMAGE_SCN_LNK_REMOVE` and `IMAGE_SCN_MEM_READ` flags. 161 - `readonly` = if this flag is not specified, add the `IMAGE_SCN_MEM_WRITE` 162 flag. 163 - `exclude` = add the `IMAGE_SCN_LNK_REMOVE` and `IMAGE_SCN_MEM_READ` flags. 164 - `debug` = add the `IMAGE_SCN_CNT_INITIALIZED_DATA`, 165 `IMAGE_SCN_MEM_DISCARDABLE` and `IMAGE_SCN_MEM_READ` flags. 166 - `code` = add the `IMAGE_SCN_CNT_CODE`, `IMAGE_SCN_MEM_EXECUTE` and 167 `IMAGE_SCN_MEM_READ` flags. 168 - `data` = add the `IMAGE_SCN_CNT_INITIALIZED_DATA` and `IMAGE_SCN_MEM_READ` 169 flags. 170 - `share` = add the `IMAGE_SCN_MEM_SHARED` and `IMAGE_SCN_MEM_READ` flags. 171 172.. option:: --strip-all-gnu 173 174 Remove all symbols, debug sections and relocations from the output. This option 175 is equivalent to GNU :program:`objcopy`'s ``--strip-all`` switch. 176 177.. option:: --strip-all, -S 178 179 For ELF objects, remove from the output all symbols and non-alloc sections not 180 within segments, except for .gnu.warning, .ARM.attribute sections and the 181 section name table. 182 183 For COFF and Mach-O objects, remove all symbols, debug sections, and 184 relocations from the output. 185 186.. option:: --strip-debug, -g 187 188 Remove all debug sections from the output. 189 190.. option:: --strip-symbol <symbol>, -N 191 192 Remove all symbols named ``<symbol>`` from the output. Can be specified 193 multiple times to remove multiple symbols. 194 195.. option:: --strip-symbols <filename> 196 197 Remove all symbols whose names appear in the file ``<filename>``, from the 198 output. In the file, each line represents a single symbol name, with leading 199 and trailing whitespace ignored, as is anything following a '#'. Can be 200 specified multiple times to read names from multiple files. 201 202.. option:: --strip-unneeded-symbol <symbol> 203 204 Remove from the output all symbols named ``<symbol>`` that are local or 205 undefined and are not required by any relocation. 206 207.. option:: --strip-unneeded-symbols <filename> 208 209 Remove all symbols whose names appear in the file ``<filename>``, from the 210 output, if they are local or undefined and are not required by any relocation. 211 In the file, each line represents a single symbol name, with leading and 212 trailing whitespace ignored, as is anything following a '#'. Can be specified 213 multiple times to read names from multiple files. 214 215.. option:: --strip-unneeded 216 217 Remove from the output all local or undefined symbols that are not required by 218 relocations. Also remove all debug sections. 219 220.. option:: --version, -V 221 222 Display the version of the :program:`llvm-objcopy` executable. 223 224.. option:: --wildcard, -w 225 226 Allow wildcard syntax for symbol-related flags. On by default for 227 section-related flags. Incompatible with --regex. 228 229 Wildcard syntax allows the following special symbols: 230 231 ====================== ========================= ================== 232 Character Meaning Equivalent 233 ====================== ========================= ================== 234 ``*`` Any number of characters ``.*`` 235 ``?`` Any single character ``.`` 236 ``\`` Escape the next character ``\`` 237 ``[a-z]`` Character class ``[a-z]`` 238 ``[!a-z]``, ``[^a-z]`` Negated character class ``[^a-z]`` 239 ====================== ========================= ================== 240 241 Additionally, starting a wildcard with '!' will prevent a match, even if 242 another flag matches. For example ``-w -N '*' -N '!x'`` will strip all symbols 243 except for ``x``. 244 245 The order of wildcards does not matter. For example, ``-w -N '*' -N '!x'`` is 246 the same as ``-w -N '!x' -N '*'``. 247 248.. option:: @<FILE> 249 250 Read command-line options and commands from response file `<FILE>`. 251 252ELF-SPECIFIC OPTIONS 253-------------------- 254 255The following options are implemented only for ELF objects. If used with other 256objects, :program:`llvm-objcopy` will either emit an error or silently ignore 257them. 258 259.. option:: --add-symbol <name>=[<section>:]<value>[,<flags>] 260 261 Add a new symbol called ``<name>`` to the output symbol table, in the section 262 named ``<section>``, with value ``<value>``. If ``<section>`` is not specified, 263 the symbol is added as an absolute symbol. The ``<flags>`` affect the symbol 264 properties. Accepted values are: 265 266 - `global` = the symbol will have global binding. 267 - `local` = the symbol will have local binding. 268 - `weak` = the symbol will have weak binding. 269 - `default` = the symbol will have default visibility. 270 - `hidden` = the symbol will have hidden visibility. 271 - `protected` = the symbol will have protected visibility. 272 - `file` = the symbol will be an `STT_FILE` symbol. 273 - `section` = the symbol will be an `STT_SECTION` symbol. 274 - `object` = the symbol will be an `STT_OBJECT` symbol. 275 - `function` = the symbol will be an `STT_FUNC` symbol. 276 - `indirect-function` = the symbol will be an `STT_GNU_IFUNC` symbol. 277 278 Additionally, the following flags are accepted but ignored: `debug`, 279 `constructor`, `warning`, `indirect`, `synthetic`, `unique-object`, `before`. 280 281 Can be specified multiple times to add multiple symbols. 282 283.. option:: --allow-broken-links 284 285 Allow :program:`llvm-objcopy` to remove sections even if it would leave invalid 286 section references. Any invalid sh_link fields will be set to zero. 287 288.. option:: --build-id-link-dir <dir> 289 290 Set the directory used by :option:`--build-id-link-input` and 291 :option:`--build-id-link-output`. 292 293.. option:: --build-id-link-input <suffix> 294 295 Hard-link the input to ``<dir>/xx/xxx<suffix>``, where ``<dir>`` is the directory 296 specified by :option:`--build-id-link-dir`. The path used is derived from the 297 hex build ID. 298 299.. option:: --build-id-link-output <suffix> 300 301 Hard-link the output to ``<dir>/xx/xxx<suffix>``, where ``<dir>`` is the directory 302 specified by :option:`--build-id-link-dir`. The path used is derived from the 303 hex build ID. 304 305.. option:: --change-start <incr>, --adjust-start 306 307 Add ``<incr>`` to the program's start address. Can be specified multiple 308 times, in which case the values will be applied cumulatively. 309 310.. option:: --compress-debug-sections [<style>] 311 312 Compress DWARF debug sections in the output, using the specified style. 313 Supported styles are `zlib-gnu` and `zlib`. Defaults to `zlib` if no style is 314 specified. 315 316.. option:: --decompress-debug-sections 317 318 Decompress any compressed DWARF debug sections in the output. 319 320.. option:: --discard-locals, -X 321 322 Remove local symbols starting with ".L" from the output. 323 324.. option:: --extract-dwo 325 326 Remove all sections that are not DWARF .dwo sections from the output. 327 328.. option:: --extract-main-partition 329 330 Extract the main partition from the output. 331 332.. option:: --extract-partition <name> 333 334 Extract the named partition from the output. 335 336.. option:: --globalize-symbol <symbol> 337 338 Mark any defined symbols named ``<symbol>`` as global symbols in the output. 339 Can be specified multiple times to mark multiple symbols. 340 341.. option:: --globalize-symbols <filename> 342 343 Read a list of names from the file ``<filename>`` and mark defined symbols with 344 those names as global in the output. In the file, each line represents a single 345 symbol, with leading and trailing whitespace ignored, as is anything following 346 a '#'. Can be specified multiple times to read names from multiple files. 347 348.. option:: --input-target <format>, -I 349 350 Read the input as the specified format. See `SUPPORTED FORMATS`_ for a list of 351 valid ``<format>`` values. If unspecified, :program:`llvm-objcopy` will attempt 352 to determine the format automatically. 353 354.. option:: --keep-file-symbols 355 356 Keep symbols of type `STT_FILE`, even if they would otherwise be stripped. 357 358.. option:: --keep-global-symbol <symbol> 359 360 Make all symbols local in the output, except for symbols with the name 361 ``<symbol>``. Can be specified multiple times to ignore multiple symbols. 362 363.. option:: --keep-global-symbols <filename> 364 365 Make all symbols local in the output, except for symbols named in the file 366 ``<filename>``. In the file, each line represents a single symbol, with leading 367 and trailing whitespace ignored, as is anything following a '#'. Can be 368 specified multiple times to read names from multiple files. 369 370.. option:: --keep-section <section> 371 372 When removing sections from the output, do not remove sections named 373 ``<section>``. Can be specified multiple times to keep multiple sections. 374 375.. option:: --keep-symbol <symbol>, -K 376 377 When removing symbols from the output, do not remove symbols named 378 ``<symbol>``. Can be specified multiple times to keep multiple symbols. 379 380.. option:: --keep-symbols <filename> 381 382 When removing symbols from the output do not remove symbols named in the file 383 ``<filename>``. In the file, each line represents a single symbol, with leading 384 and trailing whitespace ignored, as is anything following a '#'. Can be 385 specified multiple times to read names from multiple files. 386 387.. option:: --localize-hidden 388 389 Make all symbols with hidden or internal visibility local in the output. 390 391.. option:: --localize-symbol <symbol>, -L 392 393 Mark any defined non-common symbol named ``<symbol>`` as a local symbol in the 394 output. Can be specified multiple times to mark multiple symbols as local. 395 396.. option:: --localize-symbols <filename> 397 398 Read a list of names from the file ``<filename>`` and mark defined non-common 399 symbols with those names as local in the output. In the file, each line 400 represents a single symbol, with leading and trailing whitespace ignored, as is 401 anything following a '#'. Can be specified multiple times to read names from 402 multiple files. 403 404.. option:: --new-symbol-visibility <visibility> 405 406 Specify the visibility of the symbols automatically created when using binary 407 input or :option:`--add-symbol`. Valid options are: 408 409 - `default` 410 - `hidden` 411 - `internal` 412 - `protected` 413 414 The default is `default`. 415 416.. option:: --output-target <format>, -O 417 418 Write the output as the specified format. See `SUPPORTED FORMATS`_ for a list 419 of valid ``<format>`` values. If unspecified, the output format is assumed to 420 be the same as the value specified for :option:`--input-target` or the input 421 file's format if that option is also unspecified. 422 423.. option:: --prefix-alloc-sections <prefix> 424 425 Add ``<prefix>`` to the front of the names of all allocatable sections in the 426 output. 427 428.. option:: --prefix-symbols <prefix> 429 430 Add ``<prefix>`` to the front of every symbol name in the output. 431 432.. option:: --preserve-dates, -p 433 434 Preserve access and modification timestamps in the output. 435 436.. option:: --rename-section <old>=<new>[,<flag>,...] 437 438 Rename sections called ``<old>`` to ``<new>`` in the output, and apply any 439 specified ``<flag>`` values. See :option:`--set-section-flags` for a list of 440 supported flags. Can be specified multiple times to rename multiple sections. 441 442.. option:: --set-start-addr <addr> 443 444 Set the start address of the output to ``<addr>``. Overrides any previously 445 specified :option:`--change-start` or :option:`--adjust-start` options. 446 447.. option:: --split-dwo <dwo-file> 448 449 Equivalent to running :program:`llvm-objcopy` with :option:`--extract-dwo` and 450 ``<dwo-file>`` as the output file and no other options, and then with 451 :option:`--strip-dwo` on the input file. 452 453.. option:: --strip-dwo 454 455 Remove all DWARF .dwo sections from the output. 456 457.. option:: --strip-non-alloc 458 459 Remove from the output all non-allocatable sections that are not within 460 segments. 461 462.. option:: --strip-sections 463 464 Remove from the output all section headers and all section data not within 465 segments. Note that many tools will not be able to use an object without 466 section headers. 467 468.. option:: --target <format>, -F 469 470 Equivalent to :option:`--input-target` and :option:`--output-target` for the 471 specified format. See `SUPPORTED FORMATS`_ for a list of valid ``<format>`` 472 values. 473 474.. option:: --weaken-symbol <symbol>, -W 475 476 Mark any global symbol named ``<symbol>`` as a weak symbol in the output. Can 477 be specified multiple times to mark multiple symbols as weak. 478 479.. option:: --weaken-symbols <filename> 480 481 Read a list of names from the file ``<filename>`` and mark global symbols with 482 those names as weak in the output. In the file, each line represents a single 483 symbol, with leading and trailing whitespace ignored, as is anything following 484 a '#'. Can be specified multiple times to read names from multiple files. 485 486.. option:: --weaken 487 488 Mark all defined global symbols as weak in the output. 489 490SUPPORTED FORMATS 491----------------- 492 493The following values are currently supported by :program:`llvm-objcopy` for the 494:option:`--input-target`, :option:`--output-target`, and :option:`--target` 495options. For GNU :program:`objcopy` compatibility, the values are all bfdnames. 496 497- `binary` 498- `ihex` 499- `elf32-i386` 500- `elf32-x86-64` 501- `elf64-x86-64` 502- `elf32-iamcu` 503- `elf32-littlearm` 504- `elf64-aarch64` 505- `elf64-littleaarch64` 506- `elf32-littleriscv` 507- `elf64-littleriscv` 508- `elf32-powerpc` 509- `elf32-powerpcle` 510- `elf64-powerpc` 511- `elf64-powerpcle` 512- `elf32-bigmips` 513- `elf32-ntradbigmips` 514- `elf32-ntradlittlemips` 515- `elf32-tradbigmips` 516- `elf32-tradlittlemips` 517- `elf64-tradbigmips` 518- `elf64-tradlittlemips` 519- `elf32-sparc` 520- `elf32-sparcel` 521 522Additionally, all targets except `binary` and `ihex` can have `-freebsd` as a 523suffix. 524 525BINARY INPUT AND OUTPUT 526----------------------- 527 528If `binary` is used as the value for :option:`--input-target`, the input file 529will be embedded as a data section in an ELF relocatable object, with symbols 530``_binary_<file_name>_start``, ``_binary_<file_name>_end``, and 531``_binary_<file_name>_size`` representing the start, end and size of the data, 532where ``<file_name>`` is the path of the input file as specified on the command 533line with non-alphanumeric characters converted to ``_``. 534 535If `binary` is used as the value for :option:`--output-target`, the output file 536will be a raw binary file, containing the memory image of the input file. 537Symbols and relocation information will be discarded. The image will start at 538the address of the first loadable section in the output. 539 540EXIT STATUS 541----------- 542 543:program:`llvm-objcopy` exits with a non-zero exit code if there is an error. 544Otherwise, it exits with code 0. 545 546BUGS 547---- 548 549To report bugs, please visit <https://bugs.llvm.org/>. 550 551There is a known issue with :option:`--input-target` and :option:`--target` 552causing only ``binary`` and ``ihex`` formats to have any effect. Other values 553will be ignored and :program:`llvm-objcopy` will attempt to guess the input 554format. 555 556SEE ALSO 557-------- 558 559:manpage:`llvm-strip(1)` 560