objdump






objdump − display information from object files.

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]
        [−F|−−file−offsets]
        [−−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]
        [−P options|−−private=options]
        [−r|−−reloc]
        [−R|−−dynamic−reloc]
        [−s|−−full−contents]
        [−W[lLiaprmfFsoRt]|
         −−dwarf[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,=frames−interp,=str,=loc,=Ranges,=pubtypes,=trace_info,=trace_abbrev,=trace_aranges,=gdb_index]]
        [−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]
        [−−prefix=prefix]
        [−−prefix−strip=level]
        [−−insn−width=width]
        [−V|−−version]
        [−H|−−help]
        objfile...

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









                             ‐2‐


the member object files.

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,−P,−r,−R,−s,−S,−t,−T,−V,−x
must be given.

−a

−−archive−header
    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

−−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.











                             ‐3‐


−g

−−debugging
    Display debugging information.  This attempts to parse
    STABS and IEEE debugging format information stored in
    the file and print it out using a C like syntax.  If
    neither of these formats are found this option falls
    back on the −W option to print any DWARF information in
    the file.

−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.

    If the target is an ARM architecture this switch also
    has the effect of forcing the disassembler to decode
    pieces of data found in code sections as if they were
    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.









                             ‐4‐


−F

−−file−offsets
    When disassembling sections, whenever a symbol is
    displayed, also display the file offset of the region of
    data that is about to be dumped.  If zeroes are being
    skipped, then when disassembly resumes, tell the user
    how many zeroes were skipped and the file offset of the
    location from where the disassembly resumes.  When
    dumping sections, display the file offset of the
    location from where the dump starts.

−−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

−−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

−−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










                             ‐5‐


−−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

−−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.

    If the target is an ARM architecture then this switch
    has an additional effect.  It restricts the disassembly
    to only those instructions supported by the architecture
    specified by machine.  If it is necessary to use this
    switch because the input file does not contain any
    architecture information, but it is also desired to
    disassemble all the instructions use −marm.

−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 ARM’s
    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









                             ‐6‐


    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.  intel‐mnemonic and att‐mnemonic select between
    intel mnemonic mode and AT&T mnemonic mode. intel‐
    mnemonic implies intel and att‐mnemonic implies att.
    addr64, 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 PowerPC, booke controls the disassembly of BookE
    instructions.  32 and 64 select PowerPC and PowerPC64
    disassembly, respectively.  e300 selects disassembly for
    the e300 family.  440 selects disassembly for the
    PowerPC 440.  ppcps selects disassembly for the paired
    single instructions of the PPC750CL.

    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:

    "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









                             ‐7‐


        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
        don’t 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.

−P options

−−private=options
    Print information that is specific to the object file
    format.  The argument options is a comma separated list
    that depends on the format (the lists of options is
    displayed with the help).

    For XCOFF, the available options are: header, aout,
    sections, syms, relocs, lineno, loader, except, typchk,
    traceback and toc.











                             ‐8‐


−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.  As for −r, if used with −d
    or −D, the relocations are printed interspersed with the
    disassembly.

−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.

−−prefix=prefix
    Specify prefix to add to the absolute paths when used
    with −S.

−−prefix−strip=level
    Indicate how many initial directory names to strip off
    the hardwired absolute paths. It has no effect without
    −−prefix=prefix.

−−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.

−−insn−width=width
    Display width bytes on a single line when disassembling
    instructions.

−W[lLiaprmfFsoRt]











                             ‐9‐


−−dwarf[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,=frames−interp,=str,=loc,=Ranges,=pubtypes,=trace_info,=trace_abbrev,=trace_aranges,=gdb_index]

    Displays the contents of the debug sections in the file,
    if any are present.  If one of the optional letters or
    words follows the switch then only data found in those
    specific sections will be dumped.

    Note that there is no single letter option to display
    the content of trace sections or .gdb_index.

    Note: the output from the =info option can also be
    affected by the options −−dwarf−depth, the −−dwarf−start
    and the −−dwarf−check.

−−dwarf−depth=n
    Limit the dump of the ".debug_info" section to n
    children.  This is only useful with −−dwarf=info.  The
    default is to print all DIEs; the special value 0 for n
    will also have this effect.

    With a non‐zero value for n, DIEs at or deeper than n
    levels will not be printed.  The range for n is zero‐
    based.

−−dwarf−start=n
    Print only DIEs beginning with the DIE numbered n.  This
    is only useful with −−dwarf=info.

    If specified, this option will suppress printing of any
    header information and all DIEs before the DIE numbered
    n.  Only siblings and children of the specified DIE will
    be printed.

    This can be used in conjunction with −−dwarf−depth.

−−dwarf−check
    Enable additional checks for consistency of Dwarf
    information.

−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.









                            ‐10‐


−−stop−address=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,
    although the display format is different.  The format of
    the output depends upon the format of the file being
    dumped, but there are two main types.  One looks like
    this:

            [  4](sec  3)(fl 0x00)(ty   0)(scl   3) (nx 1) 0x00000000 .bss
            [  6](sec  1)(fl 0x00)(ty   0)(scl   2) (nx 0) 0x00000000 fred

    where the number inside the square brackets is the
    number of the entry in the symbol table, the sec number
    is the section number, the fl value are the symbol’s
    flag bits, the ty number is the symbol’s type, the scl
    number is the symbol’s storage class and the nx value is
    the number of auxilary entries associated with the
    symbol.  The last two fields are the symbol’s value and
    its name.

    The other common output format, usually seen with ELF
    based files, looks like this:

            00000000 l    d  .bss   00000000 .bss
            00000000 g       .text  00000000 fred

    Here the first number is the symbol’s value (sometimes
    refered to as its address).  The next field is actually
    a set of characters and spaces indicating the flag bits
    that are set on the symbol.  These characters are
    described below.  Next is the section with which the
    symbol is associated or *ABS* if the section is absolute
    (ie not connected with any section), or *UND* if the
    section is referenced in the file being dumped, but not
    defined there.

    After the section name comes another field, a number,
    which for common symbols is the alignment and for other
    symbol is the size.  Finally the symbol’s name is
    displayed.

    The flag characters are divided into 7 groups as
    follows:

    "l"

    "g"










                            ‐11‐


    "u"

    "!" The symbol is a local (l), global (g), unique global
        (u), neither global nor local (a space) or both
        global and local (!).  A symbol can be neither local
        or global for a variety of reasons, e.g., because it
        is used for debugging, but it is probably an
        indication of a bug if it is ever both local and
        global.  Unique global symbols are a GNU extension
        to the standard set of ELF symbol bindings.  For
        such a symbol the dynamic linker will make sure that
        in the entire process there is just one symbol with
        this name and type in use.

    "w" The symbol is weak (w) or strong (a space).

    "C" The symbol denotes a constructor (C) or an ordinary
        symbol (a space).

    "W" The symbol is a warning (W) or a normal symbol (a
        space).  A warning symbol’s name is a message to be
        displayed if the symbol following the warning symbol
        is ever referenced.

    "I"

    "i" The symbol is an indirect reference to another
        symbol (I), a function to be evaluated during reloc
        processing (i) or a normal symbol (a space).

    "d"

    "D" The symbol is a debugging symbol (d) or a dynamic
        symbol (D) or a normal symbol (a space).

    "F"

    "f"

    "O" The symbol is the name of a function (F) or a file
        (f) or an object (O) or just a normal symbol (a
        space).

−T

−−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









                            ‐12‐


    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

−−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.

nm(1), readelf(1), and the Info entries for binutils.

Copyright (c) 1991, 1992, 1993, 1994, 1995, 1996, 1997,
1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
2008, 2009, 2010, 2011, 2012 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









                            ‐13‐


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".