OBJDUMP(1)
๐ objdump(1) โ GNU Development Tools ๐
okay bestie, sit DOWN, because this is the moment you learn what objdump is and honestly? it's giving main character energy for anyone who's ever poked at a compiled binary. this is GNU Development Tools territory, and we're about to get into it. ๐
โจ NAME โจ
objdump โ display information from object files ๐ฆ
โจ SYNOPSIS โจ
objdump [-a|--archive-headers]
[-b bfdname|--target=bfdname]
[-C|--demangle[=style] ]
[-d|--disassemble[=symbol]]
[-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]
[--source-comment[=text]]
[-m machine|--architecture=machine]
[-M options|--disassembler-options=options]
[-p|--private-headers]
[-P options|--private=options]
[-r|--reloc]
[-R|--dynamic-reloc]
[-s|--full-contents]
[-Z|--decompress]
[-W|--dwarf]
[-Wa|--dwarf=abbrev]
[-WA|--dwarf=addr]
[-Wr|--dwarf=aranges]
[-Wc|--dwarf=cu_index]
[-WL|--dwarf=decodedline]
[-Wf|--dwarf=frames]
[-WF|--dwarf=frames-interp]
[-Wg|--dwarf=gdb_index]
[-Wi|--dwarf=info]
[-Wk|--dwarf=links]
[-Wo|--dwarf=loc]
[-Wm|--dwarf=macro]
[-Wp|--dwarf=pubnames]
[-Wt|--dwarf=pubtypes]
[-WR|--dwarf=Ranges]
[-Wl|--dwarf=rawline]
[-Ws|--dwarf=str]
[-WO|--dwarf=str-offsets]
[-Wu|--dwarf=trace_abbrev]
[-WT|--dwarf=trace_aranges]
[-WU|--dwarf=trace_info]
[-WK|--dwarf=follow-links]
[-WN|--dwarf=no-follow-links]
[-WD|--dwarf=use-debuginfod]
[-WE|--dwarf=do-not-use-debuginfod]
[--debug-dir=dir]
[--map-global-vars]
[-L|--process-links]
[--ctf=section]
[--sframe=section]
[-G|--stabs]
[-t|--syms]
[-T|--dynamic-syms]
[-x|--all-headers]
[-w|--wide]
[--start-address=address]
[--stop-address=address]
[--no-addresses]
[--prefix-addresses]
[--[no-]show-raw-insn]
[--adjust-vma=offset]
[--show-all-symbols]
[--dwarf-depth=n]
[--dwarf-start=n]
[--ctf-parent=section]
[--no-recurse-limit|--recurse-limit]
[--special-syms]
[--prefix=prefix]
[--prefix-strip=level]
[--insn-width=width]
[--visualize-jumps[=color|=extended-color|=off]
[--disassembler-color=[off|terminal|on|extended]
[-U method] [--unicode=method]
[-V|--version]
[-H|--help]
objfile...
โจ DESCRIPTION โจ
so like, objdump displays information about one or more object files. the options control what particular information to display. lowkey this info is mostly useful to programmers who are working on the compilation tools โ like, the ones building the toolchain โ as opposed to programmers who just want their program to compile and work. ๐
objfile... are the object files to be examined. when you specify archives, objdump shows information on each of the member object files. periodt. ๐
โจ OPTIONS โจ
the long and short forms of options, shown here as alternatives, are equivalent. and listen โ 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. like, you can't just run it naked, bestie. ๐
-a,--archive-headerโ if any of theobjfilefiles are archives, display the archive header information (in a format similar tols -l). besides the information you could list withar tv,objdump -aalso shows the object file format of each archive member. iconic. ๐ธ--adjust-vma=offsetโ 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 asa.out. ๐ซถ-b bfdname,--target=bfdnameโ specify that the object-code format for the object files is bfdname. this option may not be necessary;objdumpcan automatically recognize many formats. ngl, it's kinda smart like that. โจ
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. ๐
-C,--demangle[=style]โ 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. so demure, so mindful. ๐--recurse-limit,--no-recurse-limit,--recursion-limit,--no-recursion-limitโ enables or disables a limit on the amount of recursion performed whilst demangling strings. since the name mangling formats allow for an infinite level of recursion it is possible to create strings whose decoding will exhaust the amount of stack space available on the host machine, triggering a memory fault. the limit tries to prevent this from happening by restricting recursion to 2048 levels of nesting. ๐ฅ
the default is for this limit to be enabled, but disabling it may be necessary in order to demangle truly complicated names. note however that if the recursion limit is disabled then stack exhaustion is possible and any bug reports about such an event will be rejected. so likeโฆ choose wisely bestie. ๐ญ
-g,--debuggingโ display debugging information. this attempts to parse STABS debugging format information stored in the file and print it out using a C like syntax. if no STABS debugging was found this option falls back on the-Woption to print any DWARF information in the file. ๐-e,--debugging-tagsโ like-g, but the information is generated in a format compatible withctagstool. ๐-d,--disassemble,--disassemble=symbolโ display the assembler mnemonics for the machine instructions from the input file. this option only disassembles those sections which are expected to contain instructions. if the optional symbol argument is given (perhaps multiple times), then display the assembler mnemonics starting at (all the) symbol. if symbol is a function name then disassembly will stop at the end of the function, otherwise it will stop when the next symbol is encountered. if there are no matches for any symbol then nothing will be displayed. ๐
note if the --dwarf=follow-links option is enabled then any symbol tables in linked debug info files will be read in and used when disassembling. ๐
-D,--disassemble-allโ like-d, but disassemble the contents of all non-empty non-bss sections, not just those expected to contain instructions.-jmay be used to select specific sections. ๐ฆ
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. ๐ง
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. ๐ฅ
note if the --dwarf=follow-links option is enabled then any symbol tables in linked debug info files will be read in and used when disassembling. ๐
--no-addressesโ when disassembling, don't print addresses on each line or for symbols and relocation offsets. in combination with--no-show-raw-insnthis may be useful for comparing compiler output. very demure, very minimal. ๐--prefix-addressesโ when disassembling, print the complete address on each line. this is the older disassembly format. vintage, honestly. ๐ฆ-EB,-EL,--endian={big|little}โ 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. ๐-f,--file-headersโ display summary information from the overall header of each of theobjfilefiles. โจ-F,--file-offsetsโ 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. ๐ธ--file-start-contextโ 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. ๐ซถ-h,--section-headers,--headersโ display summary information from the section headers of the object file. ๐
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. ๐ญ
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. โญ
-H,--helpโ print a summary of the options toobjdumpand exit. your little cheat sheet, bestie. ๐-i,--infoโ display a list showing all architectures and object formats available for specification with-bor-m. ๐-jname,--section=name โ show me the info for the section called name, bestie. You can pass this one multiple times if you're nosy about more than one section, no cap. ๐--map-global-varsโ spills all the global variable tea ๐ต. This one only works when the object file was compiled with the debug option โ more precisely, it's leaning on DWARF2 debug information entries. It's the move when you wanna track the location and the type of every single global variable in the object file you handed over. obsessed.-L,--process-linksโ shows the contents of non-debug sections that live in separate debuginfo files linked to the main file ๐ฆ. Heads up though: this option automatically implies-WK, and only the sections you actually asked for with other command line options will get displayed. It's giving "you get what you ordered, nothing extra." โจ-l,--line-numbersโ labels the display using debugging information, so you get the filename and source line numbers that correspond to the object code or relocs being shown ๐. Only useful with-d,-D, or-rโ so don't be surprised when it does nothing on its own, babe.-mmachine,--architecture=machine โ tells objdump which architecture to use when disassembling object files ๐ง. Iconic when you're disassembling files that don't describe their own architecture info, like S-records. Wanna see the available architectures? Use the-ioption, periodt.
For most architectures you can hand over an architecture name and a machine name, separated by a colon ๐ซถ. So foo:bar refers to the bar machine type inside the foo architecture. Super helpful when objdump has been configured to support multiple architectures.
If the target is an ARM architecture, this switch does a lil extra: it restricts the disassembly to only the instructions supported by the architecture that machine specifies ๐ธ. And if you had to use this switch because the input file has no architecture info, but you still wanna disassemble all the instructions โ use -marm. Noted, queen. ๐
-Moptions,--disassembler-options=options โ passes target specific info straight to the disassembler ๐ซ. Only supported on some targets, just so you know. Need more than one disassembler option? Either use multiple-Moptions, or pile them into one comma separated list.
For ARC:dspcontrols the printing of DSP instructions,spfpselects the printing of FPX single precision FP instructions,dpfpselects the printing of FPX double precision FP instructions,quarkse_emselects the printing of special QuarkSE-EM instructions,fpudaselects the printing of double precision assist instructions,fpusselects the printing of FPU single precision FP instructions, whilefpudselects the printing of FPU double precision FP instructions. Plus you can choose to have all the immediates printed in hexadecimal usinghex๐ง. By default, short immediates print in decimal, while long immediate values print as hexadecimal.
cpu=... lets you enforce a particular ISA when disassembling instructions, overriding the -m value or whatever's chillin' in the ELF file ๐ฅ. Handy for picking ARC EM or HS ISA, because the architecture is the same for those two and the disassembler has to rely on private ELF header data to decide if the code is EM or HS. You can specify this multiple times โ but only the latest value gets used. Valid values are the same as for the assembler's -mcpu=... option.
If the target is an ARM architecture, this switch picks which register name set the disassembler uses ๐. -M reg-names-std (the default) selects the register names from ARM's instruction set documentation, except register 13 is called sp, register 14 is called lr, and register 15 is called pc. -M reg-names-apcs selects the name set used by the ARM Procedure Call Standard, while -M reg-names-raw just uses r followed by the register number.
There are also two variants on the APCS register naming scheme: -M reg-names-atpcs and -M reg-names-special-atpcs, which use the ARM/Thumb Procedure Call Standard naming conventions ๐. (Either with the normal register names or the special register names.)
You can also use this option on ARM architectures to force the disassembler to interpret all instructions as Thumb instructions, by using the switch --disassembler-options=force-thumb ๐. Lowkey a lifesaver when you're trying to disassemble thumb code produced by other compilers.
For AArch64 targets this switch sets whether instructions are disassembled as the most general instruction using the -M no-aliases option, or whether instruction notes get generated as comments in the disassembly using -M notes ๐. Also, the -M annotate option customises the handling of undefined instructions when disassembling executables and shared libraries. Normally the disassembler just shows the hexadecimal value of the undefined instruction, but with annotation enabled it first tries to find a symbol whose value matches the instruction's encoding ๐. If there's a match, the symbol name gets displayed instead. So useful when disassembling non-code sections that might contain function and data addresses.
For the x86, some of the options duplicate functions of the -m switch, but they allow finer grained control โญ:
"x86-64","i386","i8086"โ select disassembly for the given architecture."intel","att"โ pick between intel syntax mode and AT&T syntax mode."amd64","intel64"โ pick between AMD64 ISA and Intel64 ISA."intel-mnemonic","att-mnemonic"โ pick between intel mnemonic mode and AT&T mnemonic mode. Note:"intel-mnemonic"implies"intel", and"att-mnemonic"implies"att"."addr64","addr32","addr16","data32","data16"โ specify the default address size and operand size. These five options get overridden if"x86-64","i386"or"i8086"appear later in the option string โ ๏ธ."suffix"โ when in AT&T mode, and also for a limited set of instructions when in Intel mode, this tells the disassembler to print a mnemonic suffix even when the suffix could be inferred by the operands, or โ for certain instructions โ by the execution mode's defaults."annotate-immediates"โ displays the symbol associated with immediate values, should there be one ๐. Only works on executable binaries and shared libraries โ not static object files.
For PowerPC, the -M argument raw selects disassembly of hardware insns rather than aliases ๐. So you'll see "rlwinm" rather than "clrlwi", and "addi" rather than "li". All of the -m arguments for gas that select a CPU are supported. These are: 403, 405, 440, 464, 476, 601, 603, 604, 620, 7400, 7410, 7450, 7455, 750cl, 821, 850, 860, a2, booke, booke32, cell, com, e200z2, e200z4, e300, e500, e500mc, e500mc64, e500x2, e5500, e6500, efs, power4, power5, power6, power7, power8, power9, power10, power11, ppc, ppc32, ppc64, ppc64bridge, ppcps, pwr, pwr2, pwr4, pwr5, pwr5x, pwr6, pwr7, pwr8, pwr9, pwr10, pwr11, pwrx, titan, vle, and future โจ. 32 and 64 modify the default or a prior CPU selection, disabling and enabling 64-bit insns respectively. In addition, altivec, any, lsp, htm, vsx, spe and spe2 add capabilities to a previous or later CPU selection. any will disassemble any opcode known to binutils, but in cases where an opcode has two different meanings or different arguments, you may not see the disassembly you expect ๐ญ. And if you disassemble without giving a CPU selection, a default gets chosen from information BFD gleaned from the object file's headers โ but again, the result may not be what you expected.
For RISC-V, these options are supported ๐ฆ:
"max"โ disassemble without checking the architecture string. This is a best effort mode, so for overlapping ISA extensions the first match (possibly incorrect in a given context) will be used to decode the instruction. It's useful if the ELF file doesn't expose an ISA string, preventing automatic ISA subset deduction, and the default fallback ISA string ("rv64gc") doesn't cover all instructions in the binary."numeric"โ print numeric register names rather than ABI names (e.g., print"x2"instead of"sp")."no-aliases"โ disassemble only into canonical instructions. For example, compressed instructions will be represented as such ("addi sp,sp,-128"will be"c.addi16sp sp,-128")."priv-spec=SPEC"โ print the CSR according to the chosen privilege spec version (e.g.,1.10,1.11,1.12,1.13).
For MIPS, this option controls the printing of instruction mnemonic names and register names in disassembled instructions ๐. Multiple selections from the following may be specified as a comma separated string, and invalid options are ignored:
"no-aliases"โ 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."msa"โ disassemble MSA instructions."virt"โ disassemble the virtualization ASE instructions."xpa"โ disassemble the eXtended Physical Address (XPA) ASE instructions."gpr-names=ABI"โ 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"โ print FPR (floating-point register) names as appropriate for the specified ABI. By default, FPR numbers are printed rather than names."cp0-names=ARCH"โ 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=ARCHโ prints HWR names (that's hardware register, the thing therdhwrinstruction uses) the way they should look for the CPU or architecture you name in ARCH. If you don't say anything? It just goes with whatever arch and CPU the binary you're disassembling has. lowkey smart of it ๐reg-names=ABIโ prints GPR and FPR names matching the ABI you picked. yes bestie, the registers get their government names ๐reg-names=ARCHโ prints CPU-specific register names (CP0 register names and HWR names) for whichever CPU or architecture you chose. it's giving custom โจ
For literally any of the options up above, you can pass ABI or ARCH as a number instead of a name, and you'll get numbers printed rather than names for whatever register types you selected. Wanna see the full menu of ABI and ARCH values you can use? Run --help. that's it, that's the trick ๐ซถ
For VAX, you can hand over function entry addresses with -M entry:0xf00ba. And yes you can stack this multiple times โ you'll need to, if you're disassembling VAX binary files that have no symbol tables at all (think ROM dumps ๐). Because without it, that function entry mask gets decoded as if it were VAX instructions, and then the rest of the function goes completely sideways and disassembles wrong. so like, do it. ๐
-p,--private-headersโ prints info that's specific to the object file format. Exactly what gets printed depends on the format, and honestly for some formats nothing extra comes out at all. vibes vary ๐ฆ-Poptions,--private=optionsโ prints object-file-format-specific info, where options is a comma separated list that depends on the format. (You can see the lists of options with the help.) ๐
For XCOFF, the available options are:
headeraoutsectionssymsrelocslineno,loaderexcepttypchktracebacktocldinfo
For PE, the available options are:
headersections
Not every object format supports this option, bestie. In particular, ELF does not use it. nope, not even a little. ๐ญ
-r,--relocโ prints the file's relocation entries. And if you pair it with-dor-D, the relocations get printed interspersed with the disassembly. cute little interleaving moment โจ-R,--dynamic-relocโ prints the dynamic relocation entries of the file. This one only means anything for dynamic objects, like certain kinds of shared libraries. Same deal as-r: use it with-dor-Dand the relocations come out interspersed with the disassembly. ๐
Note:objdumpdoes not support displayingRELRtype relocations. Those can be displayed by thereadelfprogram. so if that's what you need, go knock on readelf's door ๐
-s,--full-contentsโ displays the full contents of sections, and it's often used together with-jto ask for specific sections only. By default, all non-empty non-bss sections get displayed. Also by default, any compressed section shows up in its compressed form. Want to actually see it decompressed? Add the-Zoption to the command line. periodt ๐-S,--sourceโ displays source code intermixed with the disassembly, if that's even possible. It implies-d. ๐ธ--show-all-symbolsโ when disassembling, shows all the symbols that match a given address, not just the first one it bumps into. no favorites here ๐--source-comment[=txt]โ like-S, except every source code line gets displayed with a prefix of txt. Usually txt is a comment string, which is how you tell the assembler code apart from the source code. And if you don't give a txt? It defaults to"# "โ that's a hash followed by a space. ๐--prefix=prefixโ specifies the prefix to add to the absolute paths when you're using it with-S. ๐ฆ--prefix-strip=levelโ tells it how many initial directory names to strip off those hardwired absolute paths. Heads up: it does nothing without--prefix=prefix. like, zero effect, bestie. ๐--show-raw-insnโ when disassembling instructions, prints the instruction in hex and in symbolic form. This is the default... except when--prefix-addressesis used. ๐--no-show-raw-insnโ when disassembling instructions, does not print the instruction bytes. This is the default when--prefix-addressesis used. โจ--insn-width=widthโ displays width bytes on a single line when disassembling instructions. keep it tidy ๐--visualize-jumps[=color|=extended-color|=off]โ visualizes jumps that stay inside a function by drawing ASCII art between the start and target addresses. iconic, honestly.
The optional =color argument adds color to the output using simple terminal colors. Or, the =extended-color argument adds color using 8bit colors instead โ but those might not work on every terminal, so ymmv ๐ซถ
And if you ever need to turn visualize-jumps back off after you enabled it earlier, use visualize-jumps=off.
--disassembler-color=off--disassembler-color=terminal--disassembler-color=on|color|colour--disassembler-color=extended|extended-color|extended-colourโ enables or disables the use of colored syntax highlighting in disassembly output. The default behaviour is decided by a configure time option. Note that not all architectures support colored syntax highlighting, and depending on the terminal you're using, colored output may not actually be legible. ๐ญ
The on argument adds colors using simple terminal colors.
The terminal argument does the same thing โ but only if the output device is a terminal.
The extended-color argument is similar to on, except it uses 8-bit colors. Those may not work on all terminals. ๐
The off argument disables colored disassembly.
-W[lLiaprmfFsoORtUuTgAckK],--dwarf[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,=frames-interp,=str,=str-offsets,=loc,=Ranges,=pubtypes,=trace_info,=trace_abbrev,=trace_aranges,=gdb_index,=addr,=cu_index,=links,=follow-links]โ displays the contents of the DWARF debug sections in the file, if any of them are even present. Compressed debug sections get automatically decompressed (temporarily!) before they're displayed. And if one or more of the optional letters or words follows the switch, then only those type(s) of data get dumped. โจ
The letters and words refer to the following info:
a,=abbrevโ displays the contents of the.debug_abbrevsection. ๐A,=addrโ displays the contents of the.debug_addrsection.c,=cu_indexโ displays the contents of the.debug_cu_indexand/or.debug_tu_indexsections. ๐ฆf,=framesโ displays the raw contents of a.debug_framesection.F,=frames-interpโ displays the interpreted contents of a.debug_framesection. (capital letter, glow-up version ๐ )g,=gdb_indexโ displays the contents of the.gdb_indexand/or.debug_namessections.i,=infoโ displays the contents of the.debug_infosection. Note: the output from this option can also be restricted by using the--dwarf-depthand--dwarf-startoptions. ๐ธk,=linksโ displays the contents of the.gnu_debuglink,.gnu_debugaltlinkand.debug_supsections, if any of them are present. It also displays any links to separate dwarf object files (dwo), if they're specified by theDW_AT_GNU_dwo_nameorDW_AT_dwo_nameattributes in the.debug_infosection. ๐ฅK,=follow-linksโ displays the contents of any selected debug sections found in linked, separate debug info file(s). Heads up: this can result in multiple versions of the same debug section being displayed if it exists in more than one file. ๐
On top of that, when displaying DWARF attributes, if a form is found that references the separate debug info file, then the referenced contents get displayed too.
Note โ in some distributions this option is enabled by default. It can be disabled via theNdebug option. The default can be chosen when configuring the binutils via the--enable-follow-debug-links=yesor--enable-follow-debug-links=nooptions. If those aren't used, then the default is to enable the following of debug links.
Note โ if support for thedebuginfodprotocol was enabled when the binutils were built, then this option will also include an attempt to contact anydebuginfodservers mentioned in theDEBUGINFOD_URLSenvironment variable. This could take some time to resolve. ๐ญ This behaviour can be disabled via the=do-not-use-debuginfoddebug option.
N,=no-follow-linksโ disables the following of links to separate debug info files. ๐ซD,=use-debuginfodโ enables contactingdebuginfodservers if there's a need to follow debug links. This is the default behaviour. โญE,=do-not-use-debuginfodโ disables contactingdebuginfodservers when there's a need to follow debug links.l,=rawlineโ displays the contents of the.debug_linesection in a raw format.L,=decodedlineโ displays the interpreted contents of the.debug_linesection. ๐m,=macroโ displays the contents of the.debug_macroand/or.debug_macinfosections.o,=locโ displays the contents of the.debug_locand/or.debug_loclistssections. ๐O,=str-offsetsโ displays the contents of the.debug_str_offsetssection.p,=pubnamesโ displays the contents of the.debug_pubnamesand/or.debug_gnu_pubnamessections.r,=arangesโ displays the contents of the.debug_arangessection. ๐ฆR,=Rangesโ displays the contents of the.debug_rangesand/or.debug_rnglistssections. (yes, capital R in=Ranges, don't come for me ๐ )s,=strโ displays the contents of the.debug_str,.debug_line_strand/or.debug_str_offsetssections.t,=pubtypeโ displays the contents of the.debug_pubtypesand/or.debug_gnu_pubtypessections. ๐T,=trace_arangesโ displays the contents of the.trace_arangessection.u,=trace_abbrevโ displays the contents of the.trace_abbrevsection.U,=trace_infoโ displays the contents of the.trace_infosection. ๐
--dwarf-depth=nโ caps how deep the dump of the.debug_infosection goes, only counting n children. Only does anything with--debug-dump=info. Default vibe = print every single DIE (and honestly, the special value0for n does the exact same thing, so it's a no-op with extra steps, bestie).
With a non-zero n, any DIE sitting at n levels deep or deeper justโฆ doesn't get printed. And heads up: the range for n is zero-based. ๐
--dwarf-start=nโ only prints DIEs starting from the DIE numbered n. Again, only useful with--debug-dump=info.
If you pass it, it suppresses printing of any header info and all DIEs before the one numbered n. Only siblings and children of that specified DIE make it to the output.
You can stack it with --dwarf-depth. Cute combo. ๐
--dwarf-checkโ turns on extra consistency checks for Dwarf information. Extra paranoid, extra thorough, we love that for you. โจ--debug-dir=dirโ search dir when hunting for separate debug info files. Like a little scavenger hunt but for symbols. ๐--ctf[=section]โ shows you the contents of the specified CTF section. CTF sections are basically nesting dolls โ they contain a ton of subsections, and all of them get displayed in order. ๐ช
By default it displays the name of the section called .ctf, which is the name emitted by ld.
--ctf-parent=memberโ okay so if a CTF section has ambiguously-defined types, it'll be an archive of many CTF dictionaries, all inheriting from one dictionary that holds the unambiguous types. That member is by default named.ctf, same as the section containing it โ but you can change that name using the"ctf_link_set_memb_name_changer"function at link time. When you're looking at CTF archives made by a linker that used the name changer to rename the parent archive member,--ctf-parentlets you specify the name used for the parent. ๐ซถ--ctf-parent-section=sectionโ this one lets you pick a completely different section for the CTF parent dictionary (the one with the unambiguous types) than the child dictionaries (the ambiguous remainder). The linker does not emit ELF objects structured like this, but some third-party linkers may. It's also convenient to inspect CTF written out as multiple raw files to compose them withobjcopy, which can put them in different ELF sections but not in different members of a single CTF dict. ๐ง--sframe[=section]โ displays the contents of the specified SFrame section.
By default it displays the name of the section named .sframe, which is the name emitted by ld. โจ
-G,--stabsโ displays the full contents of any sections requested. Shows the contents of the.staband.stab.indexand.stab.exclsections from an ELF file. This is only useful on systems (such as Solaris 2.0) where".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--symsoutput anyway. ๐คท--start-address=addressโ starts displaying data at the specified address. This affects the output of the-d,-rand-soptions. ๐--stop-address=addressโ stops displaying data at the specified address. This affects the output of the-d,-rand-soptions. ๐-t,--symsโ prints the symbol table entries of the file. This is similar to what thenmprogram gives you, although the display format is different. The format of the output depends on 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 auxiliary 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 referred 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","u","!"โ 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"โ the symbol is weak (w) or strong (a space)."C"โ the symbol denotes a constructor (C) or an ordinary symbol (a space)."W"โ 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"โ 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"โ the symbol is a debugging symbol (d) or a dynamic symbol (D) or a normal symbol (a space)."F","f","O"โ 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-symsโ prints the dynamic symbol table entries of the file. This is only meaningful for dynamic objects, such as certain types of shared libraries. It's similar to whatnmgives you when you pass it the-D(--dynamic) option. ๐ฅ
The output format is similar to the one --syms produces, except an extra field gets 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. ๐
--special-symsโ when displaying symbols, include the ones the target considers special in some way and which would not normally be of interest to the user. The hidden gems. ๐-U [d|i|l|e|x|h],--unicode=[default|invalid|locale|escape|hex|highlight]โ controls the display of UTF-8 encoded multibyte characters in strings. The default (--unicode=default) is to give them no special treatment. The--unicode=localeoption displays the sequence in the current locale, which may or may not support them. The options--unicode=hexand--unicode=invaliddisplay them as hex byte sequences enclosed by either angle brackets or curly braces.
The --unicode=escape option displays them as escape sequences (\uxxxx) and the --unicode=highlight option displays them as escape sequences highlighted in red (if supported by the output device). The colouring is intended to draw attention to the presence of unicode sequences where they might not be expected. ๐
-V,--versionโ prints the version number ofobjdumpand exits. Short and sweet, periodt. โ๏ธ-x,--all-headersโ displays all available header information, including the symbol table and relocation entries. Using-xis equivalent to specifying all of-a -f -h -p -r -t. The everything-bagel of flags. ๐ฅฏ-w,--wideโ formats some lines for output devices that have more than 80 columns. Also does not truncate symbol names when they are displayed. No more ellipsis erasure, bestie. ๐-z,--disassemble-zeroesโ normally the disassembly output will skip blocks of zeroes. This option directs the disassembler to disassemble those blocks, just like any other data. Zeroes deserve screen time too. ๐-Z,--decompressโ the-Zoption is meant to be used in conunction with the-soption. It instructsobjdumpto decompress any compressed sections before displaying their contents. (And yes, "conunction" โ the typo is canon, we don't touch the lore. ๐)@fileโ reads command-line options from file. The options read are inserted in place of the original@fileoption. 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. ๐
๐ธ SEE ALSO ๐ธ
nm(1), readelf(1), and the Info entries for binutils.
๐ COPYRIGHT ๐
Copyright (c) 1991-2026 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".
and that's the whole page, bestie ๐ this one shipped in binutils-2.47, dated 2026-08-11, and it's filed under OBJDUMP(1). go disassemble something iconic. ๐ฆโจ
๐ฆ where this page comes from
- arch rolling: binutils 2.47-4 ยท GPL-2.0-or-later AND GPL-3.0-or-later AND LGPL-2.0-or-later AND LGPL-3.0-or-later AND GFDL-1.3 AND FSFAP
- ๐ girlified by deepseek-ai/DeepSeek-V4.1-Flash on : a language model's rewrite of the original, under its terms