OBJCOPY(1) GNU Development Tools OBJCOPY(1)
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]
[-K symbolname|--keep-symbol=symbolname]
[-N symbolname|--strip-symbol=symbolname]
[--strip-unneeded-symbol=symbolname]
[-G symbolname|--keep-global-symbol=symbolname]
[-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]
[--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]
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OBJCOPY(1) GNU Development Tools OBJCOPY(1)
[--prefix-sections=string]
[--prefix-alloc-sections=string]
[--add-gnu-debuglink=path-to-file]
[--only-keep-debug]
[--writable-text]
[--readonly-text]
[--pure]
[--impure]
[-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).
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).
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OBJCOPY(1) GNU Development Tools OBJCOPY(1)
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
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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.
-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
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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
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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
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--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.
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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.
--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
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OBJCOPY(1) GNU Development Tools OBJCOPY(1)
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.
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--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.
--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.
--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.
The intention is that this option will be used in
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OBJCOPY(1) GNU Development Tools OBJCOPY(1)
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.
-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.
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OBJCOPY(1) GNU Development Tools OBJCOPY(1)
ld(1), objdump(1), and the Info entries for binutils.
Copyright (c) 1991, 1992, 1993, 1994, 1995, 1996, 1997,
1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 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''.
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