objcopy(1)


NAME

   objcopy - copy and translate object files

SYNOPSIS

   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]
           [-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]
           [-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]
           [--strip-unneeded-symbols=filename]
           [--keep-global-symbols=filename]
           [--localize-symbols=filename]
           [--globalize-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]
           [-v|--verbose]
           [-V|--version]
           [--help] [--info]
           infile [outfile]

DESCRIPTION

   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).

   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.)

OPTIONS

   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 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 relocations from the output file for any section matching
       sectionpattern.  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.  For
       example:

                 --remove-relocations=.text.*

       will remove the relocations for all sections matching the patter
       '.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.

   --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.

   --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.

   -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 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' 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.

   --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 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 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 usng 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
       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 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 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.

   --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.

   --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.

   --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 is 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 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
   --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
       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".

   -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 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.

SEE ALSO

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

COPYRIGHT

   Copyright (c) 1991-2016 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".





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