symbols — display
symbol information about a file or process
symbols |
[-help] [-w]
[-uuid] [-arch
arch_name] [-saveSignature
path] [-symbolsPackageDir
path] [-lookup
(0x1234 | symbol) ...] file...
pid... process-name... signature... dSYM... |
The symbols command may be used to examine
library, symbol, and source line information in files and running
processes.
You may need root privileges to examine running processes.
The symbols command can be used to determine symbol availability
to tools such as Instruments, dtrace, and sample.
-help- Print a more extensive list of options
-v- Print version information
-w- Print wide output, do not clip to terminal width
-uuid- Print UUID info only.
-arch
arch_name- Specify the target architecture. The default value is
current , which matches the current system
architecture. If the current architecture is not available in the targeted
file or process, the symbols command will attempt to use
any64bit , which matches the first available 64-bit
architecture. If there is no 64-bit architecture available, the symbols
command will finally fall back to any , which
matches the first available architecture. The value
all may be used to iterate over all architectures in
a target. The arch name may also be any of the commonly used architecture
mnemonics, for example i386,
x86_64, or arm
-cpuType
#- Specify the target architecture cpu type as a numeric value
-cpuSubtype
#- Specify the target architecture cpu subtype as a numeric value
- Do not print library level information. This also supresses printing of
any lower level information, which implies
-noRegions, -noSymbols,
and -noSources
-noRegions- Do not print segment/section level information. This also supresses
printing of any lower level information, which implies
-noSymbols and
-noSources
-noSymbols- Do not print symbol level information. This also supresses printing of any
lower level information, which implies
-noSources
-noSources- Do not print source level information
-noDemangling- Do not print the human readable form of symbol names, instead print the
name used by the linker
-printSignature- Print a "signature" for each target, which can later be used as
input to the symbols command. This is a way to archive target data for
later use. See also the
-saveSignature flag
-deepSignature- Causes all signatures to be "deep copies", containing complete
copies of all available information
-fullSourcePath- Print the entire source path for each source info
-printDsymPaths- Print the path of the dSYM file (if found) used when creating symbol
information
-lookup
(0x1234 | symbol)- Find one or more addresses or symbols in the targets. Symbols may contain
simple shell globbing style patterns.
Output from symbols has the following
format:
target [arch_name, elapsed-time]:
UUID symbol-owner-path [FLAGS]
address (size) region-name
address (size) symbol-name [FLAGS]
address (size) sourcefile : line #
Symbol owner flags have the following meanings:
- PROT
- A load command has the SG_PROTECTED_VERSION_1 flag set
- AOUT
- This symbol owner is an executable
- DYLIB
- This symbol owner is a dylib or framework
- DYLIB-STUB
- This symbol owner is used only by the linker
- DYLD
- This symbol owner is the runtime dynamic linker
- BUNDLE
- This symbol owner is a loadable bundle
- OBJECT
- This symbol owner is an unlinked object file
- KEXT-BUNDLE
- This symbol owner is a kext
- dSYM_v#
- This symbol owner is a dSYM, of version '#'
- DYLDSHAREDCACHE
- This symbol owner was found in the dyld shared cache
- ObjC-RR
- This symbol owner supports manual retain-release
- ObjC-GC
- This symbol owner supports old-style garbage collection
- SLID
- This symbol owner was relocated from its base address
- PIE
- This symbol owner is compiled position independent
- RESTRICTED
- This symbol owner has a restrict segment/section
- STATIC-LIB
- This symbol-owner is from a static library (.a)
- FaultedFromDisk
- The data for this symbol owner was found on disk
- FaultedFromTask
- The data for this symbol owner was retrieved from a running task
- FaultedFromSelfDyldSharedCache
- The data for this symbol owner was found in the current processes dyld
shared cache
- FilesetEntry
- This symbol owner is a member of a fileset kernel collection
- Found-dSYM
- A dSYM was found for this symbol owner
- Found-Binary-via-dSYM-colocation
- The binary for this symbol owner was found by looking up the dSYM, and
then looking next to the dSYM
- Found-Binary-via-dSYM-plist
- The binary for this symbol owner was found by looking up the dSYM, and
then reading its plist
- MMap32
- The symbol owner is using a mmap'd file cache for symbol information
- MMap64
- The symbol owner is using a mmap'd file cache for symbol information
- Private
- This symbol owner cannot be cached
- Empty
- No data was found for this symbol owner
Symbol flags have the following meanings:
- FUNC
- This symbol has executable code
- DYLD-STUB
- This symbol is a stub used by the dynamic linker
- OBJC
- This symbol is an Objective C method
- THUMB
- This symbol uses thumb instruction encoding
- OMIT-FP
- This symbol does not create a frame pointer.
- EXT
- This symbol has external visibility
- PEXT
- This symbol has private-external visibility
- LENGTH
- The length of this symbol is known, not guessed
- NameNList
- The name of this symbol comes from NList data
- NameDwarf
- The name of this symbol comes from Dwarf data
- NameDwarfMIPSLinkage
- The name of this symbol is from specialized Dwarf
- MangledNameNList
- The mangled name of this symbol is from NList data
- MangledNameDwarf
- The mangled name of this symbol is from Dwarf data
- MangledNameDwarfMIPSLinkage
- The mangled name of this symbol is from specialized Dwarf
- Merged
- This symbol has multiple data sources
- NList
- This symbol was found in NList data
- Dwarf
- This symbol was found in Dwarf data
- DebugMap
- This symbol was found in DebugMap data
- FunctionStarts
- This symbol was found in function starts data
symbols uses multiple sources of symbol
information. All sources are queried, and the resulting data is merged.
NLIST symbol information is found in the LINKEDIT segment. It is
imprecise, and only contains a starting address, not a length or ending
address. Nlist data is not required to (and typically does not) reference
all symbols. Usually only external symbol information is available. Even
that may be removed by use of
strip(1)
DEBUG MAP symbol information is multi-part. A per-symbol reference
in the original file points to an external file containing additional debug
information, usually DWARF.
FUNCTION STARTS symbol information is found in the
LC_FUNCTION_STARTS load command of the target. It is imprecise, and only
contains a starting address, not a length or ending address. Furthermore, it
contains no name or mangled name information. The LC_FUNCTION_STARTS load
command is optional, it may not be found in all targets.
DWARF symbol information is true debug info. It is usually precise
(but it is not required to be). When available, dwarf information is treated
as more reliable than any other information source, and conflicts are
resolved in favor of dwarf data.
DSYM. A dSYM is an external file containing DWARF and NLIST symbol
information.
Kernel symbols are available by using the special pid
"-1". This includes loaded kexts.
A signature is the information needed to reconstruct symbol
information at a later date. For example, a signature contains a list of
libraries, and for each library a UUID and the addresses the segments were
loaded at. You can also ask for a "deep" signature, which contains
complete information about every piece of information symbols could find.
This can be very useful for later diagnosis and exploration.
A symbols package is a directory with "deep" signatures
for one or more binary images. When a directory is specified with
-symbolsPackageDir, symbols will output a deep signature for each binary
image slice it reads. These files contain enough information to symbolicate
application stack traces (such as those generated by crash reports) with
function names and file names/line numbers.