NAME
objdump - display information from object files.
SYNOPSIS
objdump [-aï archiveheaders]
[-b bfdnameï target=bfdname]
[-Cï demangle[=style] ]
[-dï disassemble]
[-Dï disassembleall]
[-zï disassemblezeroes]
[-EBï-ELï endian={big ï little }]
[-fï fileheaders]
[ filestartcontext]
[-gï debugging]
[-hï sectionheadersï headers]
[-iï info]
[-j sectionï section=section]
[-lï linenumbers]
[-Sï source]
[-m machineï architecture=machine]
[-M optionsï disassembleroptions=options]
[-pï privateheaders]
[-rï reloc]
[-Rï dynamicreloc]
[-sï fullcontents]
[-Gï stabs]
[-tï syms]
[-Tï dynamicsyms]
[-xï allheaders]
[-wï wide]
[ startaddress=address]
[ stopaddress=address]
[ prefixaddresses]
[--[no]showrawinsn]
[ adjustvma=offset]
[-Vï version]
[-Hï help]
objfile...
DESCRIPTION
objdump displays information about one or more object files. The options control what
particular information to display. This information is mostly useful to programmers who are
working on the compilation tools, as opposed to programmers who just want their program to
compile and work.
objfile... are the object files to be examined. When you specify archives, objdump shows
information on each of the member object files.
OPTIONS
The long and short forms of options, shown here as alternatives, are equivalent. At least one
option from the list -a,-d,-D,-f,-g,-G,-h,-H,-p,-r,-R,-S,-t,-T,-V,-x must be given.
-a
archiveheader
If any of the objfile files are archives, display the archive header information (in a format
similar to ls -l). Besides the information you could list with ar tv, objdump -a shows the
object file format of each archive member.
adjustvma=offset
When dumping information, first add offset to all the section addresses. This is useful if
the section addresses do not correspond to the symbol table, which can happen when
putting sections at particular addresses when using a format which can not represent
section addresses, such as a.out.
-b bfdname
target=bfdname
Specify that the objectcode format for the object files is bfdname. This option may not
be necessary; objdump can automatically recognize many formats.
For example,
objdump b oasys m vax h fu.o
displays summary information from the section headers (-h) of fu.o, which is explicitly
identified (-m) as a VAX object file in the format produced by Oasys compilers. You can
list the formats available with the -i option.
-C
demangle[=style]
Decode (demangle) lowlevel symbol names into userlevel names. Besides removing
any initial underscore prepended by the system, this makes C++ function names readable.
Different compilers have different mangling styles. The optional demangling style
argument can be used to choose an appropriate demangling style for your compiler.
-G
debugging
Display debugging information. This attempts to parse debugging information stored in
the file and print it out using a C like syntax. Only certain types of debugging information
have been implemented.
-d
disassemble
Display the assembler mnemonics for the machine instructions from objfile. This option
only disassembles those sections which are expected to contain instructions.
-D
disassembleall
Like -d, but disassemble the contents of all sections, not just those expected to contain
instructions.
prefixaddresses
When disassembling, print the complete address on each line. This is the older
disassembly format.
disassemblezeroes
Normally the disassembly output will skip blocks of zeroes. This option directs the
disassembler to disassemble those blocks, just like any other data.
-EB
-EL
endian={bigïlittle}
Specify the endianness of the object files. This only affects disassembly. This can be
useful when disassembling a file format which does not describe endianness information,
such as Srecords.
-f
fileheader
Display summary information from the overall header of each of the objfile files.
filestartcontext
Specify that when displaying interlisted source code/disassembly (assumes -S) from a
file that has not yet been displayed, extend the context to the start of the file.
-h
sectionheader
header
Display summary information from the section headers of the object file.
File segments may be relocated to nonstandard addresses, for example by using the
-Ttext, -Tdata, or -Tbss options to ld. However, some object file formats, such as
a.out, do not store the starting address of the file segments. In those situations, although
ld relocates the sections correctly, using objdump -h to list the file section headers
cannot show the correct addresses. Instead, it shows the usual addresses, which are
implicit for the target.
help
Print a summary of the options to objdump and exit.
-i
info
Display a list showing all architectures and object formats available for specification with
-b or -m.
-j name
section=name
Display information only for section name.
-l
linenumbers
Label the display (using debugging information) with the filename and source line
numbers corresponding to the object code or relocs shown. Only useful with -d, -D, or
-r.
-m machine
architecture=machine
Specify the architecture to use when disassembling object files. This can be useful when
disassembling object files which do not describe architecture information, such as
Srecords. You can list the available architectures with the -i option.
-M options
disassembleroptions=options
Pass target specific information to the disassembler. Only supported on some targets.
If the target is an ARM architecture then this switch can be used to select which register
name set is used during disassembler. Specifying -M regnamestd (the default) will
select the register names as used in ARM's instruction set documentation, but with
register 13 called 'sp', register 14 called 'lr' and register 15 called 'pc'. Specifying -M
regnamesapcs will select the name set used by the ARM Procedure Call Standard,
whilst specifying -M regnamesraw will just use r followed by the register number.
There are also two variants on the APCS register naming scheme enabled by -M
regnamesatpcs and -M regnamesspecialatpcs which use the ARM/Thumb
Procedure Call Standard naming conventions. (Either with the normal register name or
the special register names).
This option can also be used for ARM architectures to force the disassembler to interpret
all instructions as THUMB instructions by using the switch
disassembleroptions=forcethumb. This can be useful when attempting to
disassemble thumb code produced by other compilers.
-p
privateheaders
Print information that is specific to the object file format. The exact information printed
depends upon the object file format. For some object file formats, no additional
information is printed.
-r
reloc
Print the relocation entries of the file. If used with -d or -D, the relocations are printed
interspersed with the disassembly.
-R
dynamicreloc
Print the dynamic relocation entries of the file. This is only meaningful for dynamic
objects, such as certain types of shared libraries.
-s
fullcontents
Display the full contents of any sections requested.
-S
source
Display source code intermixed with disassembly, if possible. Implies -d.
showrawinsn
When disassembling instructions, print the instruction in hex as well as in symbolic form.
This is the default except when prefixaddresses is used.
noshowrawinsn
When disassembling instructions, do not print the instruction bytes. This is the default
when prefixaddresses is used.
-G
stabs
Display the full contents of any sections requested. Display the contents of the .stab and
.stab.index and .stab.excl sections from an ELF file. This is only useful on systems (such
as Solaris 2.0) in which .stab debugging symboltable entries are carried in an ELF
section. In most other file formats, debugging symboltable entries are interleaved with
linkage symbols, and are visible in the syms output.
startaddress=address
Start displaying data at the specified address. This affects the output of the -d, -r and
-s options.
stopaddress=address
Stop displaying data at the specified address. This affects the output of the -d, -r and -s
options.
-t
syms
Print the symbol table entries of the file. This is similar to the information provided by the
nm program.
-T
dynamicsyms
Print the dynamic symbol table entries of the file. This is only meaningful for dynamic
objects, such as certain types of shared libraries. This is similar to the information
provided by the nm program when given the -D ( dynamic) option.
version
Print the version number of objdump and exit.
-x
allheader
Display all available header information, including the symbol table and relocation
entries. Using -x is equivalent to specifying all of -a -f -h -r -t.
-w
wide
Format some lines for output devices that have more than 80 columns.
SEE ALSO
nm (1), readelf (1), and the Info entries for binutils.
COPYRIGHT
Copyright (c) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001 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 FrontCover Texts, and with no
BackCover Texts. A copy of the license is included in the section entitled ``GNU Free
Documentation License''.