gnu Binary Utilities - 4. objcopy

Go to the first, previous, next, last section, table of contents.

# 4. objcopy

    objcopy [ -F bfdname | --target=bfdname ]
            [ -I bfdname | --input-target=bfdname ]
            [ -O bfdname | --output-target=bfdname ]
            [ -S | --strip-all ]  [ -g | --strip-debug ]
            [ -K symbolname | --keep-symbol=symbolname ]
            [ -N symbolname | --strip-symbol=symbolname ]
            [ -L symbolname | --localize-symbol=symbolname ]
            [ -W symbolname | --weaken-symbol=symbolname ]
            [ -x | --discard-all ]  [ -X | --discard-locals ]
            [ -b byte | --byte=byte ]
            [ -i interleave | --interleave=interleave ]
            [ -R sectionname | --remove-section=sectionname ]
            [ -p | --preserve-dates ] [ --debugging ]
            [ --gap-fill=val ] [ --pad-to=address ]
            [ --set-start=val ] [ --adjust-start=incr ]
            [ --change-addresses=incr ]
            [ --change-section-address=section{=,+,-}val ]
            [ --change-section-lma=section{=,+,-}val ]
            [ --change-section-vma=section{=,+,-}val ]
            [ --change-warnings ] [ --no-change-warnings ]
            [ --set-section-flags=section=flags ]
            [ --add-section=sectionname=filename ]
            [ --change-leading-char ] [ --remove-leading-char ]
            [ --weaken ]
            [ -v | --verbose ] [ -V | --version ]  [ --help ]
            infile [outfile]

The GNU `objcopy` utility copies the contents of an object file to another. `objcopy` uses the GNU BFD Library to read and write the object files. It can write the destination object file in a format different from that of the source object file. The exact behavior of `objcopy` is controlled by command-line options.

`objcopy` creates temporary files to do its translations and deletes them afterward. `objcopy` uses BFD to do all its translation work; it has access to all the formats described in BFD and thus is able to recognize most formats without being told explicitly. See section `BFD' in Using LD.

`objcopy` can be used to generate S-records by using an output target of ``srec'` (e.g., use ``-O srec'`).

`objcopy` can be used to generate a raw binary file by using an output target of ``binary'` (e.g., use ``-O binary'`). When `objcopy` generates a raw binary file, it will essentially produce a memory dump of the contents of the input object file. All symbols and relocation information will be discarded. The memory dump will start at the load address of the lowest section copied into the output file.

When generating an S-record or a raw binary file, it may be helpful to use ``-S'` to remove sections containing debugging information. In some cases ``-R'` will be useful to remove sections which contain information which is not needed by the binary file.

`infile`
`outfile`
  The source and output files, respectively. If you do not specify outfile, `objcopy` creates a temporary file and destructively renames the result with the name of infile.
`-I bfdname`
`--input-target=bfdname`
  Consider the source file's object format to be bfdname, rather than attempting to deduce it. See section 16.1 Target Selection, for more information.
`-O bfdname`
`--output-target=bfdname`
  Write the output file using the object format bfdname. See section 16.1 Target Selection, for more information.
`-F bfdname`
`--target=bfdname`
  Use bfdname as the object format for both the input and the output file; i.e., simply transfer data from source to destination with no translation. See section 16.1 Target Selection, for more information.
`-R sectionname`
`--remove-section=sectionname`
  Remove any section named sectionname from the output file. This option may be given more than once. Note that using this option inappropriately may make the output file unusable.
`-S`
`--strip-all`
  Do not copy relocation and symbol information from the source file.
`-g`
`--strip-debug`
  Do not copy debugging symbols from the source file.
`--strip-unneeded`
  Strip all symbols that are not needed for relocation processing.
`-K symbolname`
`--keep-symbol=symbolname`
  Copy only symbol symbolname from the source file. This option may be given more than once.
`-N symbolname`
`--strip-symbol=symbolname`
  Do not copy symbol symbolname from the source file. This option may be given more than once.
`-L symbolname`
`--localize-symbol=symbolname`
  Make symbol symbolname local to the file, so that it is not visible externally. This option may be given more than once.
`-W symbolname`
`--weaken-symbol=symbolname`
  Make symbol symbolname weak. This option may be given more than once.
`-x`
`--discard-all`
  Do not copy non-global symbols from the source file.
`-X`
`--discard-locals`
  Do not copy compiler-generated local symbols. (These usually start with ``L'` or ``.'`.)
`-b byte`
`--byte=byte`
  Keep only every byteth byte of the input file (header data is not affected). byte can be in the range from 0 to interleave-1, where interleave is given by the ``-i'` or ``--interleave'` option, or the default of 4. This option is useful for creating files to program ROM. It is typically used with an `srec` output target.
`-i interleave`
`--interleave=interleave`
  Only copy one out of every interleave bytes. Select which byte to copy with the -b or ``--byte'` option. The default is 4. `objcopy` ignores this option if you do not specify either ``-b'` or ``--byte'`.
`-p`
`--preserve-dates`
  Set the access and modification dates of the output file to be the same as those of the input file.
`--debugging`
  Convert debugging information, if possible. This is not the default because only certain debugging formats are supported, and the conversion process can be time consuming.
`--gap-fill val`
  Fill gaps between sections with val. This operation applies to the load address (LMA) of the sections. It is done by increasing the size of the section with the lower address, and filling in the extra space created with val.
`--pad-to address`
  Pad the output file up to the load address address. This is done by increasing the size of the last section. The extra space is filled in with the value specified by ``--gap-fill'` (default zero).
`--set-start val`
  Set the address of the new file to val. Not all object file formats support setting the start address.
`--change-start incr`
`--adjust-start incr`
  Change the start address by adding incr. Not all object file formats support setting the start address.
`--change-addresses incr`
`--adjust-vma incr`
  Change the VMA and LMA addresses of all sections, as well as the start address, by adding incr. Some object file formats do not permit section addresses to be changed arbitrarily. Note that this does not relocate the sections; if the program expects sections to be loaded at a certain address, and this option is used to change the sections such that they are loaded at a different address, the program may fail.
`--change-section-address section{=,+,-}val`
`--adjust-section-vma section{=,+,-}val`
  Set or change both the VMA address and the LMA address of the named section. If ``='` is used, the section address is set to val. Otherwise, val is added to or subtracted from the section address. See the comments under ``--change-addresses'`, above. If section does not exist in the input file, a warning will be issued, unless ``--no-change-warnings'` is used.
`--change-section-lma section{=,+,-}val`
  Set or change the LMA address of the named section. The LMA address is the address where the section will be loaded into memory at program load time. Normally this is the same as the VMA address, which is the address of the section at program run time, but on some systems, especially those where a program is held in ROM, the two can be different. If ``='` is used, the section address is set to val. Otherwise, val is added to or subtracted from the section address. See the comments under ``--change-addresses'`, above. If section does not exist in the input file, a warning will be issued, unless ``--no-change-warnings'` is used.
`--change-section-vma section{=,+,-}val`
  Set or change the VMA address of the named section. The VMA address is the address where the section will be located once the program has started executing. Normally this is the same as the LMA address, which is the address where the section will be loaded into memory, but on some systems, especially those where a program is held in ROM, the two can be different. If ``='` is used, the section address is set to val. Otherwise, val is added to or subtracted from the section address. See the comments under ``--change-addresses'`, above. If section does not exist in the input file, a warning will be issued, unless ``--no-change-warnings'` is used.
`--change-warnings`
`--adjust-warnings`
  If ``--change-section-address'` or ``--change-section-lma'` or ``--change-section-vma'` is used, and the named section does not exist, issue a warning. This is the default.
`--no-change-warnings`
`--no-adjust-warnings`
  Do not issue a warning if ``--change-section-address'` or ``--adjust-section-lma'` or ``--adjust-section-vma'` is used, even if the named section does not exist.
`--set-section-flags section=flags`
  Set the flags for the named section. The flags argument is a comma separated string of flag names. The recognized names are ``alloc'`, ``contents'`, ``load'`, ``readonly'`, ``code'`, ``data'`, and ``rom'`. You can set the ``contents'` flag for a section which does not have contents, but it is not meaningful to clear the ``contents'` flag of a section which does have contents--just remove the section instead. Not all flags are meaningful for all object file formats.
`--add-section sectionname=filename`
  Add a new section named sectionname while copying the file. The contents of the new section are taken from the file filename. The size of the section will be the size of the file. This option only works on file formats which can support sections with arbitrary names.
`--change-leading-char`
  Some object file formats use special characters at the start of symbols. The most common such character is underscore, which compilers often add before every symbol. This option tells `objcopy` to change the leading character of every symbol when it converts between object file formats. If the object file formats use the same leading character, this option has no effect. Otherwise, it will add a character, or remove a character, or change a character, as appropriate.
`--remove-leading-char`
  If the first character of a global symbol is a special symbol leading character used by the object file format, remove the character. The most common symbol leading character is underscore. This option will remove a leading underscore from all global symbols. This can be useful if you want to link together objects of different file formats with different conventions for symbol names. This is different from `--change-leading-char` because it always changes the symbol name when appropriate, regardless of the object file format of the output file.
`--weaken`
  Change all global symbols in the file to be weak. This can be useful when building an object which will be linked against other objects using the `-R` option to the linker. This option is only effective when using an object file format which supports weak symbols.
`-V`
`--version`
  Show the version number of `objcopy`.
`-v`
`--verbose`
  Verbose output: list all object files modified. In the case of archives, ``objcopy -V'` lists all members of the archive.
`--help`
  Show a summary of the options to `objcopy`.

Go to the first, previous, next, last section, table of contents.