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
dyldinfo(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), dyldinfo(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)