Skip site navigation (1)Skip section navigation (2)

FreeBSD Man Pages

Man Page or Keyword Search:
Man Architecture
Apropos Keyword Search (all sections) Output format
home | help
OBJCOPY(1)		     GNU Development Tools		    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 interleave|--interleave=interleave]
	       [-j sectionname|--only-section=sectionname]
	       [-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]
	       [--rename-section oldname=newname[,flags]]
	       [--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]
	       [--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]
	       [--extract-symbol]
	       [--writable-text]
	       [--readonly-text]
	       [--pure]
	       [--impure]
	       [-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 raw binary 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 sectionname
       --only-section=sectionname
	   Copy	only the named section 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.

       -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 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
	   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.

       --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
	   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 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	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, 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.

       --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>

       --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.

       --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.

	   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.

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

	   *<sets the virtual and load addresses of every section to zero;>
	   *<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.

       -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, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
       2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 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 1.1 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".

binutils-2.17.50		  2010-10-30			    OBJCOPY(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | SEE ALSO | COPYRIGHT

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=objcopy&sektion=1&manpath=FreeBSD+9.2-RELEASE>

home | help