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