objdump - Unix, Linux Command
NAME
objdump - display information from object files.
SYNOPSIS
objdump [-a|--archive-headers]
[-b bfdname|--target=bfdname]
[-C|--demangle[=style] ]
[-d|--disassemble]
[-D|--disassemble-all]
[-z|--disassemble-zeroes]
[-EB|-EL|--endian={big | little }]
[-f|--file-headers]
[--file-start-context]
[-g|--debugging]
[-e|--debugging-tags]
[-h|--section-headers|--headers]
[-i|--info]
[-j section|--section=section]
[-l|--line-numbers]
[-S|--source]
[-m machine|--architecture=machine]
[-M options|--disassembler-options=options]
[-p|--private-headers]
[-r|--reloc]
[-R|--dynamic-reloc]
[-s|--full-contents]
[-W|--dwarf]
[-G|--stabs]
[-t|--syms]
[-T|--dynamic-syms]
[-x|--all-headers]
[-w|--wide]
[--start-address=address]
[--stop-address=address]
[--prefix-addresses]
[--[no-]show-raw-insn]
[--adjust-vma=offset]
[--special-syms]
[-V|--version]
[-H|--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,-e,-f,-g,-G,-h,-H,-p,-r,-R,-s,-S,-t,-T,-V,-x must be given.
Tag | Description |
-a
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--archive-header
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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.
|
--adjust-vma=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
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--target=bfdname
|
Specify that the object-code 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) low-level symbol names into user-level 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.
Some other types are supported by readelf -w.
|
-e
|
|
--debugging-tags
|
Like -g, but the information is generated in a format compatible
with ctags tool.
|
-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
|
|
--disassemble-all
|
Like -d, but disassemble the contents of all sections, not just
those expected to contain instructions.
|
--prefix-addresses
|
When disassembling, print the complete address on each line. This is
the older disassembly format.
|
-EB
|
|
-EL
|
|
--endian={big|little}
|
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 S-records.
|
-f
|
|
--file-headers
|
Display summary information from the overall header of
each of the objfile files.
|
--file-start-context
|
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
|
|
--section-headers
|
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--headers
|
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.
|
-H
|
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--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
|
|
--line-numbers
|
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
|
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--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 S-records. You can list the available
architectures with the -i option.
|
-M options
|
|
--disassembler-options=options
|
Pass target specific information to the disassembler. Only supported on
some targets. If it is necessary to specify more than one
disassembler option then multiple -M options can be used or
can be placed together into a comma separated list.
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 reg-names-std (the default) will select the register names as
used in ARMs instruction set documentation, but with register 13 called
sp, register 14 called lr and register 15 called pc. Specifying
-M reg-names-apcs will select the name set used by the ARM
Procedure Call Standard, whilst specifying -M reg-names-raw will
just use r followed by the register number.
There are also two variants on the APCS register naming scheme enabled
by -M reg-names-atpcs and -M reg-names-special-atpcs which
use the ARM/Thumb Procedure Call Standard naming conventions. (Either
with the normal register names 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 --disassembler-options=force-thumb. This can be
useful when attempting to disassemble thumb code produced by other
compilers.
For the x86, some of the options duplicate functions of the -m
switch, but allow finer grained control. Multiple selections from the
following may be specified as a comma separated string.
x86-64, i386 and i8086 select disassembly for
the given architecture. intel and att select between
intel syntax mode and AT&T syntax mode. addr32,
addr16, data32 and data16 specify the default
address size and operand size. These four options will be overridden if
x86-64, i386 or i8086 appear later in the
option string. Lastly, suffix, when in AT&T mode,
instructs the disassembler to print a mnemonic suffix even when the
suffix could be inferred by the operands.
For PPC, booke, booke32 and booke64 select
disassembly of BookE instructions. 32 and 64 select
PowerPC and PowerPC64 disassembly, respectively. e300 selects
disassembly for the e300 family.
For MIPS, this option controls the printing of instruction mnemonic
names and register names in disassembled instructions. Multiple
selections from the following may be specified as a comma separated
string, and invalid options are ignored:
Tag | Description |
no-aliases
|
Print the raw instruction mnemonic instead of some pseudo
instruction mnemonic. I.e., print daddu or or instead of move,
sll instead of nop, etc.
|
gpr-names=ABI
|
Print GPR (general-purpose register) names as appropriate
for the specified ABI. By default, GPR names are selected according to
the ABI of the binary being disassembled.
|
fpr-names=ABI
|
Print FPR (floating-point register) names as
appropriate for the specified ABI. By default, FPR numbers are printed
rather than names.
|
cp0-names=ARCH
|
Print CP0 (system control coprocessor; coprocessor 0) register names
as appropriate for the CPU or architecture specified by
ARCH. By default, CP0 register names are selected according to
the architecture and CPU of the binary being disassembled.
|
hwr-names=ARCH
|
Print HWR (hardware register, used by the rdhwr instruction) names
as appropriate for the CPU or architecture specified by
ARCH. By default, HWR names are selected according to
the architecture and CPU of the binary being disassembled.
|
reg-names=ABI
|
Print GPR and FPR names as appropriate for the selected ABI.
|
reg-names=ARCH
|
Print CPU-specific register names (CP0 register and HWR names)
as appropriate for the selected CPU or architecture.
|
For any of the options listed above, ABI or
ARCH may be specified as numeric to have numbers printed
rather than names, for the selected types of registers.
You can list the available values of ABI and ARCH using
the --help option.
For VAX, you can specify function entry addresses with -M
entry:0xf00ba. You can use this multiple times to properly
disassemble VAX binary files that dont contain symbol tables (like
ROM dumps). In these cases, the function entry mask would otherwise
be decoded as VAX instructions, which would probably lead the rest
of the function being wrongly disassembled.
|
-p
|
|
--private-headers
|
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
|
|
--dynamic-reloc
|
Print the dynamic relocation entries of the file. This is only
meaningful for dynamic objects, such as certain types of shared
libraries.
|
-s
|
|
--full-contents
|
Display the full contents of any sections requested. By default all
non-empty sections are displayed.
|
-S
|
|
--source
|
Display source code intermixed with disassembly, if possible. Implies
-d.
|
--show-raw-insn
|
When disassembling instructions, print the instruction in hex as well as
in symbolic form. This is the default except when
--prefix-addresses is used.
|
--no-show-raw-insn
|
When disassembling instructions, do not print the instruction bytes.
This is the default when --prefix-addresses is used.
|
-W
|
|
--dwarf
|
Displays the contents of the DWARF debug sections in the file, if any
are present.
|
-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 symbol-table entries are carried in an ELF
section. In most other file formats, debugging symbol-table entries are
interleaved with linkage symbols, and are visible in the --syms
output.
|
--start-address=address
|
Start displaying data at the specified address. This affects the output
of the -d, -r and -s options.
|
--stop-address=address
|
Stop displaying data at the specified address. This affects the output
of the -d, -r and -s options.
|
-t
|
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--syms
|
Print the symbol table entries of the file.
This is similar to the information provided by the nm program.
|
-T
|
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--dynamic-syms
|
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.
|
--special-syms
|
When displaying symbols include those which the target considers to be
special in some way and which would not normally be of interest to the
user.
|
-V
|
|
--version
|
Print the version number of objdump and exit.
|
-x
|
|
--all-headers
|
Display all available header information, including the symbol table and
relocation entries. Using -x is equivalent to specifying all of
-a -f -h -p -r -t.
|
-w
|
|
--wide
|
Format some lines for output devices that have more than 80 columns.
Also do not truncate symbol names when they are displayed.
|
-z
|
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--disassemble-zeroes
|
Normally the disassembly output will skip blocks of zeroes. This
option directs the disassembler to disassemble those blocks, just like
any other data.
|
@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.
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SEE ALSO
nm(1), readelf(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 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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