objdump - display information from object files.


   objdump [-a|--archive-headers]
           [-b bfdname|--target=bfdname]
           [-C|--demangle[=style] ]
           [-EB|-EL|--endian={big | little }]
           [-j section|--section=section]
           [-m machine|--architecture=machine]
           [-M options|--disassembler-options=options]
           [-P options|--private=options]


   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.


   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.

       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.

       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
       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.

       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

       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.

       Like -g, but the information is generated in a format compatible
       with ctags tool.

       Display the assembler mnemonics for the machine instructions from
       objfile.  This option only disassembles those sections which are
       expected to contain instructions.

       Like -d, but disassemble the contents of all sections, not just
       those expected to contain instructions.

       This option also has a subtle effect on the disassembly of
       instructions in code sections.  When option -d is in effect objdump
       will assume that any symbols present in a code section occur on the
       boundary between instructions and it will refuse to disassemble
       across such a boundary.  When option -D is in effect however this
       assumption is supressed.  This means that it is possible for the
       output of -d and -D to differ if, for example, data is stored in
       code sections.

       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.

       When disassembling, print the complete address on each line.  This
       is the older disassembly format.

       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.

       Display summary information from the overall header of each of the
       objfile files.

       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.

       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.

       Display summary information from the section headers of the object

       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

       Note, in some cases it is possible for a section to have both the
       READONLY and the NOREAD attributes set.  In such cases the NOREAD
       attribute takes precedence, but objdump will report both since the
       exact setting of the flag bits might be important.

       Print a summary of the options to objdump and exit.

       Display a list showing all architectures and object formats
       available for specification with -b or -m.

   -j name
       Display information only for section name.

       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
       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
       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.

       For ARC, dsp controls the printing of DSP instructions, spfp
       selects the printing of FPX single precision FP instructions, dpfp
       selects the printing of FPX double precision FP instructions,
       quarkse_em selects the printing of special QuarkSE-EM instructions,
       fpuda selects the printing of double precision assist instructions,
       fpus selects the printing of FPU single precision FP instructions,
       while fpud selects the printing of FPU souble precision FP

       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

       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

       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.

           Select disassembly for the given architecture.

           Select between intel syntax mode and AT&T syntax mode.

           Select between AMD64 ISA and Intel64 ISA.

           Select between intel mnemonic mode and AT&T mnemonic mode.
           Note: "intel-mnemonic" implies "intel" and "att-mnemonic"
           implies "att".

           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.

           When in AT&T mode, instructs the disassembler to print a
           mnemonic suffix even when the suffix could be inferred by the

       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:

           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.

           Disassemble MSA instructions.

           Disassemble the virtualization ASE instructions.

           Disassemble the eXtended Physical Address (XPA) ASE

           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.

           Print FPR (floating-point register) names as appropriate for
           the specified ABI.  By default, FPR numbers are printed rather
           than names.

           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.

           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.

           Print GPR and FPR names as appropriate for the selected ABI.

           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.

       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
       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:


       Not all object formats support this option.  In particular the ELF
       format does not use it.

       Print the relocation entries of the file.  If used with -d or -D,
       the relocations are printed interspersed with the disassembly.

       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.

       Display the full contents of any sections requested.  By default
       all non-empty sections are displayed.

       Display source code intermixed with disassembly, if possible.
       Implies -d.

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

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

       When disassembling instructions, print the instruction in hex as
       well as in symbolic form.  This is the default except when
       --prefix-addresses is used.

       When disassembling instructions, do not print the instruction
       bytes.  This is the default when --prefix-addresses is used.

       Display width bytes on a single line when disassembling

       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

       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.

       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.

       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.

       Enable additional checks for consistency of Dwarf information.

       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 displaying data at the specified address.  This affects the
       output of the -d, -r and -s options.

       Stop displaying data at the specified address.  This affects the
       output of the -d, -r and -s options.

       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:

       "!" 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

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

       "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).

       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.

       The output format is similar to that produced by the --syms option,
       except that an extra field is inserted before the symbol's name,
       giving the version information associated with the symbol.  If the
       version is the default version to be used when resolving
       unversioned references to the symbol then it's displayed as is,
       otherwise it's put into parentheses.

       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.

       Print the version number of objdump and exit.

       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.

       Format some lines for output devices that have more than 80
       columns.  Also do not truncate symbol names when they are

       Normally the disassembly output will skip blocks of zeroes.  This
       option directs the disassembler to disassemble those blocks, just
       like any other data.

       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

       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) 1991-2016 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 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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