aarch64-linux-gnu-objcopy






objcopy − copy and translate object files

objcopy [−F bfdname|−−target=bfdname]
        [−I bfdname|−−input−target=bfdname]
        [−O bfdname|−−output−target=bfdname]
        [−B bfdarch|−−binary−architecture=bfdarch]
        [−S|−−strip−all]
        [−g|−−strip−debug]
        [−−strip−unneeded]
        [−K symbolname|−−keep−symbol=symbolname]
        [−N symbolname|−−strip−symbol=symbolname]
        [−−strip−unneeded−symbol=symbolname]
        [−G symbolname|−−keep−global−symbol=symbolname]
        [−−localize−hidden]
        [−L symbolname|−−localize−symbol=symbolname]
        [−−globalize−symbol=symbolname]
        [−−globalize−symbols=filename]
        [−W symbolname|−−weaken−symbol=symbolname]
        [−w|−−wildcard]
        [−x|−−discard−all]
        [−X|−−discard−locals]
        [−b byte|−−byte=byte]
        [−i [breadth]|−−interleave[=breadth]]
        [−−interleave−width=width]
        [−j sectionpattern|−−only−section=sectionpattern]
        [−R sectionpattern|−−remove−section=sectionpattern]
        [−−remove−relocations=sectionpattern]
        [−p|−−preserve−dates]
        [−D|−−enable−deterministic−archives]
        [−U|−−disable−deterministic−archives]
        [−−debugging]
        [−−gap−fill=val]
        [−−pad−to=address]
        [−−set−start=val]
        [−−adjust−start=incr]
        [−−change−addresses=incr]
        [−−change−section−address sectionpattern{=,+,−}val]
        [−−change−section−lma sectionpattern{=,+,−}val]
        [−−change−section−vma sectionpattern{=,+,−}val]
        [−−change−warnings] [−−no−change−warnings]
        [−−set−section−flags sectionpattern=flags]
        [−−add−section sectionname=filename]
        [−−dump−section sectionname=filename]
        [−−update−section sectionname=filename]
        [−−rename−section oldname=newname[,flags]]
        [−−long−section−names {enable,disable,keep}]
        [−−change−leading−char] [−−remove−leading−char]
        [−−reverse−bytes=num]
        [−−srec−len=ival] [−−srec−forceS3]
        [−−redefine−sym old=new]
        [−−redefine−syms=filename]
        [−−weaken]
        [−−keep−symbols=filename]
        [−−strip−symbols=filename]









                             ‐2‐


        [−−strip−unneeded−symbols=filename]
        [−−keep−global−symbols=filename]
        [−−localize−symbols=filename]
        [−−weaken−symbols=filename]
        [−−add−symbol name=[section:]value[,flags]]
        [−−alt−machine−code=index]
        [−−prefix−symbols=string]
        [−−prefix−sections=string]
        [−−prefix−alloc−sections=string]
        [−−add−gnu−debuglink=path‐to‐file]
        [−−keep−file−symbols]
        [−−only−keep−debug]
        [−−strip−dwo]
        [−−extract−dwo]
        [−−extract−symbol]
        [−−writable−text]
        [−−readonly−text]
        [−−pure]
        [−−impure]
        [−−file−alignment=num]
        [−−heap=size]
        [−−image−base=address]
        [−−section−alignment=num]
        [−−stack=size]
        [−−subsystem=which:major.minor]
        [−−compress−debug−sections]
        [−−decompress−debug−sections]
        [−−elf−stt−common=val]
        [−−merge−notes]
        [−−no−merge−notes]
        [−v|−−verbose]
        [−V|−−version]
        [−−help] [−−info]
        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.  Note that objcopy should be able to
copy a fully linked file between any two formats. However,
copying a relocatable object file between any two formats
may not work as expected.

     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.

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










                             ‐3‐


     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 that is not needed
by the binary file.

     Note−−−objcopy is not able to change the endianness of
its input files.  If the input format has an endianness
(some formats do not), objcopy can only copy the inputs into
file formats that have the same endianness or which have no
endianness (e.g., srec).  (However, see the −−reverse−bytes
option.)



infile

outfile
    The input 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.

−O bfdname

−−output−target=bfdname
    Write the output file using the object format bfdname.

−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.

−B bfdarch

−−binary−architecture=bfdarch
    Useful when transforming a architecture‐less input file
    into an object file.  In this case the output









                             ‐4‐


    architecture can be set to bfdarch.  This option will be
    ignored if the input file has a known bfdarch.  You can
    access this binary data inside a program by referencing
    the special symbols that are created by the conversion
    process.  These symbols are called
    _binary_objfile_start, _binary_objfile_end and
    _binary_objfile_size.  e.g. you can transform a picture
    file into an object file and then access it in your code
    using these symbols.

−j sectionpattern

−−only−section=sectionpattern
    Copy only the indicated sections from the input file to
    the output file.  This option may be given more than
    once.  Note that using this option inappropriately may
    make the output file unusable.  Wildcard characters are
    accepted in sectionpattern.

    If the first character of sectionpattern is the
    exclamation point (!) then matching sections will not be
    copied, even if earlier use of −−only−section on the
    same command line would otherwise copy it.  For example:

              −−only−section=.text.* −−only−section=!.text.foo

    will copy all sectinos maching ’.text.*’ but not the
    section ’.text.foo’.

−R sectionpattern

−−remove−section=sectionpattern
    Remove any section matching sectionpattern from the
    output file.  This option may be given more than once.
    Note that using this option inappropriately may make the
    output file unusable.  Wildcard characters are accepted
    in sectionpattern.  Using both the −j and −R options
    together results in undefined behaviour.

    If the first character of sectionpattern is the
    exclamation point (!) then matching sections will not be
    removed even if an earlier use of −−remove−section on
    the same command line would otherwise remove it.  For
    example:

              −−remove−section=.text.* −−remove−section=!.text.foo

    will remove all sections matching the pattern ’.text.*’,
    but will not remove the section ’.text.foo’.

−−remove−relocations=sectionpattern
    Remove non‐dynamic relocations from the output file for
    any section matching sectionpattern.  This option may be
    given more than once.  Note that using this option









                             ‐5‐


    inappropriately may make the output file unusable, and
    attempting to remove a dynamic relocation section such
    as .rela.plt from an executable or shared library with
    −−remove−relocations=.plt will not work.  Wildcard
    characters are accepted in sectionpattern.  For example:

              −−remove−relocations=.text.*

    will remove the relocations for all sections matching
    the pattern ’.text.*’.

    If the first character of sectionpattern is the
    exclamation point (!) then matching sections will not
    have their relocation removed even if an earlier use of
    −−remove−relocations on the same command line would
    otherwise cause the relocations to be removed.  For
    example:

              −−remove−relocations=.text.* −−remove−relocations=!.text.foo

    will remove all relocations for sections matching the
    pattern ’.text.*’, but will not remove relocations for
    the section ’.text.foo’.

−S

−−strip−all
    Do not copy relocation and symbol information from the
    source file.

−g

−−strip−debug
    Do not copy debugging symbols or sections from the
    source file.

−−strip−unneeded
    Strip all symbols that are not needed for relocation
    processing.

−K symbolname

−−keep−symbol=symbolname
    When stripping symbols, keep symbol symbolname even if
    it would normally be stripped.  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.











                             ‐6‐


−−strip−unneeded−symbol=symbolname
    Do not copy symbol symbolname from the source file
    unless it is needed by a relocation.  This option may be
    given more than once.

−G symbolname

−−keep−global−symbol=symbolname
    Keep only symbol symbolname global.  Make all other
    symbols local to the file, so that they are not visible
    externally.  This option may be given more than once.
    Note: this option cannot be used in conjunction with the
    −−globalize−symbol or −−globalize−symbols options.

−−localize−hidden
    In an ELF object, mark all symbols that have hidden or
    internal visibility as local.  This option applies on
    top of symbol‐specific localization options such as −L.

−L symbolname

−−localize−symbol=symbolname
    Convert a global or weak symbol called symbolname into a
    local symbol, so that it is not visible externally.
    This option may be given more than once.  Note − unique
    symbols are not converted.

−W symbolname

−−weaken−symbol=symbolname
    Make symbol symbolname weak. This option may be given
    more than once.

−−globalize−symbol=symbolname
    Give symbol symbolname global scoping so that it is
    visible outside of the file in which it is defined.
    This option may be given more than once.  Note: this
    option cannot be used in conjunction with the −G or
    −−keep−global−symbol options.

−w

−−wildcard
    Permit regular expressions in symbolnames used in other
    command line options.  The question mark (?), asterisk
    (*), backslash (\) and square brackets ([]) operators
    can be used anywhere in the symbol name.  If the first
    character of the symbol name is the exclamation point
    (!) then the sense of the switch is reversed for that
    symbol.  For example:

              −w −W !foo −W fo*

    would cause objcopy to weaken all symbols that start









                             ‐7‐


    with "fo" except for the symbol "foo".

−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
    If interleaving has been enabled via the −−interleave
    option then start the range of bytes to keep at the
    byteth byte.  byte can be in the range from 0 to
    breadth−1, where breadth is the value given by the
    −−interleave option.

−i [breadth]

−−interleave[=breadth]
    Only copy a range out of every breadth bytes.  (Header
    data is not affected).  Select which byte in the range
    begins the copy with the −−byte option.  Select the
    width of the range with the −−interleave−width option.

    This option is useful for creating files to program ROM.
    It is typically used with an "srec" output target.  Note
    that objcopy will complain if you do not specify the
    −−byte option as well.

    The default interleave breadth is 4, so with −−byte set
    to 0, objcopy would copy the first byte out of every
    four bytes from the input to the output.

−−interleave−width=width
    When used with the −−interleave option, copy width bytes
    at a time.  The start of the range of bytes to be copied
    is set by the −−byte option, and the extent of the range
    is set with the −−interleave option.

    The default value for this option is 1.  The value of
    width plus the byte value set by the −−byte option must
    not exceed the interleave breadth set by the
    −−interleave option.

    This option can be used to create images for two 16−bit
    flashes interleaved in a 32−bit bus by passing −b 0 −i 4
    −−interleave−width=2 and −b 2 −i 4 −−interleave−width=2
    to two objcopy commands.  If the input was ’12345678’









                             ‐8‐


    then the outputs would be ’1256’ and ’3478’
    respectively.

−p

−−preserve−dates
    Set the access and modification dates of the output file
    to be the same as those of the input file.

−D

−−enable−deterministic−archives
    Operate in deterministic mode.  When copying archive
    members and writing the archive index, use zero for
    UIDs, GIDs, timestamps, and use consistent file modes
    for all files.

    If binutils was configured with
    −−enable−deterministic−archives, then this mode is on by
    default.  It can be disabled with the −U option, below.

−U

−−disable−deterministic−archives
    Do not operate in deterministic mode.  This is the
    inverse of the −D option, above: when copying archive
    members and writing the archive index, use their actual
    UID, GID, timestamp, and file mode values.

    This is the default unless binutils was configured with
    −−enable−deterministic−archives.

−−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 start address of the new file to val.  Not all
    object file formats support setting the start address.









                             ‐9‐


−−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 sectionpattern{=,+,−}val

−−adjust−section−vma sectionpattern{=,+,−}val
    Set or change both the VMA address and the LMA address
    of any section matching sectionpattern.  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
    sectionpattern does not match any sections in the input
    file, a warning will be issued, unless
    −−no−change−warnings is used.

−−change−section−lma sectionpattern{=,+,−}val
    Set or change the LMA address of any sections matching
    sectionpattern.  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
    sectionpattern does not match any sections in the input
    file, a warning will be issued, unless
    −−no−change−warnings is used.

−−change−section−vma sectionpattern{=,+,−}val
    Set or change the VMA address of any section matching
    sectionpattern.  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









                            ‐10‐


    val.  Otherwise, val is added to or subtracted from the
    section address.  See the comments under
    −−change−addresses, above.  If sectionpattern does not
    match any sections 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 section pattern
    does not match any sections, 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 section pattern does not match any sections.

−−set−section−flags sectionpattern=flags
    Set the flags for any sections matching sectionpattern.
    The flags argument is a comma separated string of flag
    names.  The recognized names are alloc, contents, load,
    noload, readonly, code, data, rom, share, and debug.
    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.
    Note − it may be necessary to use the
    −−set−section−flags option to set the attributes of the
    newly created section.

−−dump−section sectionname=filename
    Place the contents of section named sectionname into the
    file filename, overwriting any contents that may have
    been there previously.  This option is the inverse of
    −−add−section.  This option is similar to the
    −−only−section option except that it does not create a
    formatted file, it just dumps the contents as raw binary
    data, without applying any relocations.  The option can
    be specified more than once.

−−update−section sectionname=filename
    Replace the existing contents of a section named









                            ‐11‐


    sectionname with the contents of file filename.  The
    size of the section will be adjusted to the size of the
    file.  The section flags for sectionname will be
    unchanged.  For ELF format files the section to segment
    mapping will also remain unchanged, something which is
    not possible using −−remove−section followed by
    −−add−section.  The option can be specified more than
    once.

    Note − it is possible to use −−rename−section and
    −−update−section to both update and rename a section
    from one command line.  In this case, pass the original
    section name to −−update−section, and the original and
    new section names to −−rename−section.

−−add−symbol name=[section:]value[,flags]
    Add a new symbol named name while copying the file.
    This option may be specified multiple times.  If the
    section is given, the symbol will be associated with and
    relative to that section, otherwise it will be an ABS
    symbol.  Specifying an undefined section will result in
    a fatal error.  There is no check for the value, it will
    be taken as specified.  Symbol flags can be specified
    and not all flags will be meaningful for all object file
    formats.  By default, the symbol will be global.  The
    special flag ’before=othersym’ will insert the new
    symbol in front of the specified othersym, otherwise the
    symbol(s) will be added at the end of the symbol table
    in the order they appear.

−−rename−section oldname=newname[,flags]
    Rename a section from oldname to newname, optionally
    changing the section’s flags to flags in the process.
    This has the advantage over using a linker script to
    perform the rename in that the output stays as an object
    file and does not become a linked executable.

    This option is particularly helpful when the input
    format is binary, since this will always create a
    section called .data.  If for example, you wanted
    instead to create a section called .rodata containing
    binary data you could use the following command line to
    achieve it:

              objcopy −I binary −O <output_format> −B <architecture> \
               −−rename−section .data=.rodata,alloc,load,readonly,data,contents \
               <input_binary_file> <output_object_file>

−−long−section−names {enable,disable,keep}
    Controls the handling of long section names when
    processing "COFF" and "PE−COFF" object formats.  The
    default behaviour, keep, is to preserve long section
    names if any are present in the input file.  The enable
    and disable options forcibly enable or disable the use









                            ‐12‐


    of long section names in the output object; when disable
    is in effect, any long section names in the input object
    will be truncated.  The enable option will only emit
    long section names if any are present in the inputs;
    this is mostly the same as keep, but it is left
    undefined whether the enable option might force the
    creation of an empty string table in the output file.

−−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.

−−reverse−bytes=num
    Reverse the bytes in a section with output contents.  A
    section length must be evenly divisible by the value
    given in order for the swap to be able to take place.
    Reversing takes place before the interleaving is
    performed.

    This option is used typically in generating ROM images
    for problematic target systems.  For example, on some
    target boards, the 32−bit words fetched from 8−bit ROMs
    are re‐assembled in little‐endian byte order regardless
    of the CPU byte order.  Depending on the programming
    model, the endianness of the ROM may need to be
    modified.

    Consider a simple file with a section containing the
    following eight bytes:  12345678.

    Using −−reverse−bytes=2 for the above example, the bytes
    in the output file would be ordered 21436587.

    Using −−reverse−bytes=4 for the above example, the bytes









                            ‐13‐


    in the output file would be ordered 43218765.

    By using −−reverse−bytes=2 for the above example,
    followed by −−reverse−bytes=4 on the output file, the
    bytes in the second output file would be ordered
    34127856.

−−srec−len=ival
    Meaningful only for srec output.  Set the maximum length
    of the Srecords being produced to ival.  This length
    covers both address, data and crc fields.

−−srec−forceS3
    Meaningful only for srec output.  Avoid generation of
    S1/S2 records, creating S3−only record format.

−−redefine−sym old=new
    Change the name of a symbol old, to new.  This can be
    useful when one is trying link two things together for
    which you have no source, and there are name collisions.

−−redefine−syms=filename
    Apply −−redefine−sym to each symbol pair "old new"
    listed in the file filename.  filename is simply a flat
    file, with one symbol pair per line.  Line comments may
    be introduced by the hash character.  This option may be
    given more than once.

−−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.

−−keep−symbols=filename
    Apply −−keep−symbol option to each symbol listed in the
    file filename.  filename is simply a flat file, with one
    symbol name per line.  Line comments may be introduced
    by the hash character.  This option may be given more
    than once.

−−strip−symbols=filename
    Apply −−strip−symbol option to each symbol listed in the
    file filename.  filename is simply a flat file, with one
    symbol name per line.  Line comments may be introduced
    by the hash character.  This option may be given more
    than once.

−−strip−unneeded−symbols=filename
    Apply −−strip−unneeded−symbol option to each symbol
    listed in the file filename.  filename is simply a flat
    file, with one symbol name per line.  Line comments may
    be introduced by the hash character.  This option may be









                            ‐14‐


    given more than once.

−−keep−global−symbols=filename
    Apply −−keep−global−symbol option to each symbol listed
    in the file filename.  filename is simply a flat file,
    with one symbol name per line.  Line comments may be
    introduced by the hash character.  This option may be
    given more than once.

−−localize−symbols=filename
    Apply −−localize−symbol option to each symbol listed in
    the file filename.  filename is simply a flat file, with
    one symbol name per line.  Line comments may be
    introduced by the hash character.  This option may be
    given more than once.

−−globalize−symbols=filename
    Apply −−globalize−symbol option to each symbol listed in
    the file filename.  filename is simply a flat file, with
    one symbol name per line.  Line comments may be
    introduced by the hash character.  This option may be
    given more than once.  Note: this option cannot be used
    in conjunction with the −G or −−keep−global−symbol
    options.

−−weaken−symbols=filename
    Apply −−weaken−symbol option to each symbol listed in
    the file filename.  filename is simply a flat file, with
    one symbol name per line.  Line comments may be
    introduced by the hash character.  This option may be
    given more than once.

−−alt−machine−code=index
    If the output architecture has alternate machine codes,
    use the indexth code instead of the default one.  This
    is useful in case a machine is assigned an official code
    and the tool‐chain adopts the new code, but other
    applications still depend on the original code being
    used.  For ELF based architectures if the index
    alternative does not exist then the value is treated as
    an absolute number to be stored in the e_machine field
    of the ELF header.

−−writable−text
    Mark the output text as writable.  This option isn’t
    meaningful for all object file formats.

−−readonly−text
    Make the output text write protected.  This option isn’t
    meaningful for all object file formats.

−−pure
    Mark the output file as demand paged.  This option isn’t
    meaningful for all object file formats.









                            ‐15‐


−−impure
    Mark the output file as impure.  This option isn’t
    meaningful for all object file formats.

−−prefix−symbols=string
    Prefix all symbols in the output file with string.

−−prefix−sections=string
    Prefix all section names in the output file with string.

−−prefix−alloc−sections=string
    Prefix all the names of all allocated sections in the
    output file with string.

−−add−gnu−debuglink=path‐to‐file
    Creates a .gnu_debuglink section which contains a
    reference to path‐to‐file and adds it to the output
    file.  Note: the file at path‐to‐file must exist.  Part
    of the process of adding the .gnu_debuglink section
    involves embedding a checksum of the contents of the
    debug info file into the section.

    If the debug info file is built in one location but it
    is going to be installed at a later time into a
    different location then do not use the path to the
    installed location.  The −−add−gnu−debuglink option will
    fail because the installed file does not exist yet.
    Instead put the debug info file in the current directory
    and use the −−add−gnu−debuglink option without any
    directory components, like this:

             objcopy −−add−gnu−debuglink=foo.debug

    At debug time the debugger will attempt to look for the
    separate debug info file in a set of known locations.
    The exact set of these locations varies depending upon
    the distribution being used, but it typically includes:

    "* The same directory as the executable."

    "* A sub−directory of the directory containing the
        executable"
        called .debug

    "* A global debug directory such as /usr/lib/debug."

        As long as the debug info file has been installed
        into one of these locations before the debugger is
        run everything should work correctly.

−−keep−file−symbols
    When stripping a file, perhaps with −−strip−debug or
    −−strip−unneeded, retain any symbols specifying source
    file names, which would otherwise get stripped.









                            ‐16‐


−−only−keep−debug
    Strip a file, removing contents of any sections that
    would not be stripped by −−strip−debug and leaving the
    debugging sections intact.  In ELF files, this preserves
    all note sections in the output.

    Note − the section headers of the stripped sections are
    preserved, including their sizes, but the contents of
    the section are discarded.  The section headers are
    preserved so that other tools can match up the debuginfo
    file with the real executable, even if that executable
    has been relocated to a different address space.

    The intention is that this option will be used in
    conjunction with −−add−gnu−debuglink to create a two
    part executable.  One a stripped binary which will
    occupy less space in RAM and in a distribution and the
    second a debugging information file which is only needed
    if debugging abilities are required.  The suggested
    procedure to create these files is as follows:

    1.<Link the executable as normal.  Assuming that it is
        called>
        "foo" then...

    1.<Run "objcopy −−only−keep−debug foo foo.dbg" to>
        create a file containing the debugging info.

    1.<Run "objcopy −−strip−debug foo" to create a>
        stripped executable.

    1.<Run "objcopy −−add−gnu−debuglink=foo.dbg foo">
        to add a link to the debugging info into the
        stripped executable.

        Note−−−the choice of ".dbg" as an extension for the
        debug info file is arbitrary.  Also the
        "−−only−keep−debug" step is optional.  You could
        instead do this:

    1.<Link the executable as normal.>

    1.<Copy "foo" to  "foo.full">

    1.<Run "objcopy −−strip−debug foo">

    1.<Run "objcopy −−add−gnu−debuglink=foo.full foo">

        i.e., the file pointed to by the −−add−gnu−debuglink
        can be the full executable.  It does not have to be
        a file created by the −−only−keep−debug switch.

        Note−−−this switch is only intended for use on fully
        linked files.  It does not make sense to use it on









                            ‐17‐


        object files where the debugging information may be
        incomplete.  Besides the gnu_debuglink feature
        currently only supports the presence of one filename
        containing debugging information, not multiple
        filenames on a one‐per‐object‐file basis.

−−strip−dwo
    Remove the contents of all DWARF .dwo sections, leaving
    the remaining debugging sections and all symbols intact.
    This option is intended for use by the compiler as part
    of the −gsplit−dwarf option, which splits debug
    information between the .o file and a separate .dwo
    file.  The compiler generates all debug information in
    the same file, then uses the −−extract−dwo option to
    copy the .dwo sections to the .dwo file, then the
    −−strip−dwo option to remove those sections from the
    original .o file.

−−extract−dwo
    Extract the contents of all DWARF .dwo sections.  See
    the −−strip−dwo option for more information.

−−file−alignment num
    Specify the file alignment.  Sections in the file will
    always begin at file offsets which are multiples of this
    number.  This defaults to 512.  [This option is specific
    to PE targets.]

−−heap reserve

−−heap reserve,commit
    Specify the number of bytes of memory to reserve (and
    optionally commit) to be used as heap for this program.
    [This option is specific to PE targets.]

−−image−base value
    Use value as the base address of your program or dll.
    This is the lowest memory location that will be used
    when your program or dll is loaded.  To reduce the need
    to relocate and improve performance of your dlls, each
    should have a unique base address and not overlap any
    other dlls.  The default is 0x400000 for executables,
    and 0x10000000 for dlls.  [This option is specific to PE
    targets.]

−−section−alignment num
    Sets the section alignment.  Sections in memory will
    always begin at addresses which are a multiple of this
    number.  Defaults to 0x1000.  [This option is specific
    to PE targets.]

−−stack reserve











                            ‐18‐


−−stack reserve,commit
    Specify the number of bytes of memory to reserve (and
    optionally commit) to be used as stack for this program.
    [This option is specific to PE targets.]

−−subsystem which

−−subsystem which:major

−−subsystem which:major.minor
    Specifies the subsystem under which your program will
    execute.  The legal values for which are "native",
    "windows", "console", "posix", "efi−app", "efi−bsd",
    "efi−rtd", "sal−rtd", and "xbox".  You may optionally
    set the subsystem version also.  Numeric values are also
    accepted for which.  [This option is specific to PE
    targets.]

−−extract−symbol
    Keep the file’s section flags and symbols but remove all
    section data.  Specifically, the option:

    *<removes the contents of all sections;>

    *<sets the size of every section to zero; and>

    *<sets the file’s start address to zero.>

        This option is used to build a .sym file for a
        VxWorks kernel.  It can also be a useful way of
        reducing the size of a −−just−symbols linker input
        file.

−−compress−debug−sections
    Compress DWARF debug sections using zlib with
    SHF_COMPRESSED from the ELF ABI.  Note − if compression
    would actually make a section larger, then it is not
    compressed.

−−compress−debug−sections=none

−−compress−debug−sections=zlib

−−compress−debug−sections=zlib−gnu

−−compress−debug−sections=zlib−gabi
    For ELF files, these options control how DWARF debug
    sections are compressed.  −−compress−debug−sections=none
    is equivalent to −−decompress−debug−sections.
    −−compress−debug−sections=zlib and
    −−compress−debug−sections=zlib−gabi are equivalent to
    −−compress−debug−sections.
    −−compress−debug−sections=zlib−gnu compresses DWARF
    debug sections using zlib.  The debug sections are









                            ‐19‐


    renamed to begin with .zdebug instead of .debug.  Note −
    if compression would actually make a section larger,
    then it is not compressed nor renamed.

−−decompress−debug−sections
    Decompress DWARF debug sections using zlib.  The
    original section names of the compressed sections are
    restored.

−−elf−stt−common=yes

−−elf−stt−common=no
    For ELF files, these options control whether common
    symbols should be converted to the "STT_COMMON" or
    "STT_OBJECT" type.  −−elf−stt−common=yes converts common
    symbol type to "STT_COMMON". −−elf−stt−common=no
    converts common symbol type to "STT_OBJECT".

−−merge−notes

−−no−merge−notes
    For ELF files, attempt (or do not attempt) to reduce the
    size of any SHT_NOTE type sections by removing duplicate
    notes.

−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.

−−info
    Display a list showing all architectures and object
    formats available.

@file
    Read command‐line options from file.  The options read
    are inserted in place of the original @file option.  If
    file does not exist, or cannot be read, then the option
    will be treated literally, and not removed.

    Options in file are separated by whitespace.  A
    whitespace character may be included in an option by
    surrounding the entire option in either single or double
    quotes.  Any character (including a backslash) may be









                            ‐20‐


    included by prefixing the character to be included with
    a backslash.  The file may itself contain additional
    @file options; any such options will be processed
    recursively.

ld(1), objdump(1), and the Info entries for binutils.

Copyright (c) 1991−2019 Free Software Foundation, Inc.

     Permission is granted to copy, distribute and/or modify
this document under the terms of the GNU Free Documentation
License, Version 1.3 or any later version published by the
Free Software Foundation; with no Invariant Sections, with
no Front‐Cover Texts, and with no Back‐Cover Texts.  A copy
of the license is included in the section entitled "GNU Free
Documentation License".