NM(1) General Commands Manual NM(1)
NAME
nm - display name list (symbol table)
SYNOPSIS
llvm-nm [ -agnoprumxjlPA ] [ - ] [ -t format ] [[ -arch arch_flag ]...]
[ file ... ] [ -s segname sectname ]
nm-classic [ -agnoprumxjlfPA [ s segname sectname ]] [ - ] [ -t format
] [[ -arch arch_flag ]...] [ file ... ]
DESCRIPTION
As of Xcode 8.0 the default nm(1) tool is llvm-nm(1). For the most
part nm(1) and llvm-nm(1) have the same options; notable exceptions
include -f, -s, and -L as described below. This document explains
options common between the two commands as well as some historically
relevant options supported by nm-classic(1). More help on options for
llvm-nm(1) is provided when running it with the --help option.
nm displays the name list (symbol table of nlist structures) of each
object file in the argument list. In some cases, as with an object
that has had strip(1) with its -T option used on the object, that can
be different than the dyld information. For that information use
dyld_info(1).
If an argument is an archive, a listing for each object file in the
archive will be produced. File can be of the form libx.a(x.o), in
which case only symbols from that member of the object file are listed.
(The parentheses have to be quoted to get by the shell.) If no file is
given, the symbols in a.out are listed.
Each symbol name is preceded by its value (blanks if undefined).
Unless the -m option is specified, this value is followed by one of the
following characters, representing the symbol type: U (undefined), A
(absolute), T (text section symbol), D (data section symbol), B (bss
section symbol), C (common symbol), - (for debugger symbol table
entries; see -a below), S (symbol in a section other than those above),
or I (indirect symbol). If the symbol is local (non-external), the
symbol's type is instead represented by the corresponding lowercase
letter. A lower case u in a dynamic shared library indicates a
undefined reference to a private external in another module in the same
library.
If the symbol is a Objective-C method, the symbol name is
±[Class_name(category_name) method:name:], where `+' is for class
methods, `-' is for instance methods, and (category_name) is present
only when the method is in a category.
The output is sorted alphabetically by default.
Options are:
-a Display all symbol table entries, including those inserted for
use by debuggers.
-g Display only global (external) symbols.
-n Sort numerically rather than alphabetically.
-o Prepend file or archive element name to each output line, rather
than only once.
-p Don't sort; display in symbol-table order.
-r Sort in reverse order.
-u Display only undefined symbols.
-U Don't display undefined symbols.
-m Display the N_SECT type symbols (Mach-O symbols) as
(segment_name, section_name) followed by either external or
non-external and then the symbol name. Undefined, common,
absolute and indirect symbols get displayed as (undefined),
(common), (absolute), and (indirect), respectively. Other symbol
details are displayed in a human-friendly manner, such as "[no
dead strip]". nm will display the referenced symbol for
indirect symbols and will display the name of the library
expected to provide an undefined symbol. See nlist(3) and <mach-
o/nlist.h> for more information on the nlist structure.
-x Display the symbol table entry's fields in hexadecimal, along
with the name as a string.
-j Just display the symbol names (no value or type).
-s segname sectname
List only those symbols in the section (segname,sectname). For
llvm-nm(1) this option must be last on the command line, and
after the files.
-l List a pseudo symbol .section_start if no symbol has as its
value the starting address of the section. (This is used with
the -s option above.)
-arch arch_type
Specifies the architecture, arch_type, of the file for nm(1) to
operate on when the file is a universal file (see arch(3) for
the currently known arch_types). The arch_type can be "all" to
operate on all architectures in the file. The default is to
display the symbols from only the host architecture, if the file
contains it; otherwise, symbols for all architectures in the
file are displayed.
-f format
For llvm-nm(1) this specifies the output format. Where format
can be bsd, sysv, posix or darwin.
-f For nm-classic(1) this displays the symbol table of a dynamic
library flat (as one file not separate modules). This is
obsolete and not supported with llvm-nm(1).
-A Write the pathname or library name of an object on each line.
-P Write information in a portable output format.
-t format
For the -P output, write the numeric value in the specified
format. The format shall be dependent on the single character
used as the format option-argument:
d The value shall be written in decimal (default).
o The value shall be written in octal.
x The value shall be written in hexadecimal.
-L Display the symbols in the bitcode files in the
(__LLVM,__bundle) section if present instead of the object's
symbol table. For nm-classic(1) this is the default if the
object has no symbol table and an (__LLVM,__bundle) section
exists. This option is not supported by llvm-nm(1) where
displaying llvm bitcode symbols is the default behavior.
SEE ALSO
ar(1), ar(5), Mach-O(5), stab(5), nlist(3), dyld_info(1)
BUGS
Displaying Mach-O symbols with -m is too verbose. Without the -m,
symbols in the Objective-C sections get displayed as an `s'.
Apple, Inc. December 13, 2018 NM(1)