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