Provided by: lld-8_8-3~ubuntu16.04.1_amd64 
NAME
ld.lld — ELF linker from the LLVM project
SYNOPSIS
ld.lld [options] objfile ...
DESCRIPTION
A linker takes one or more object, archive, and library files, and combines them into an
output file (an executable, a shared library, or another object file). It relocates code
and data from the input files and resolves symbol references between them.
ld.lld is a drop-in replacement for the GNU BFD and gold linkers. It accepts most of the
same command line arguments and linker scripts as GNU linkers.
ld.lld currently supports i386, x86-64, ARM, AArch64, PowerPC32, PowerPC64, MIPS32, MIPS64,
RISC-V, AMDGPU, Hexagon and SPARC V9 targets. ld.lld acts as a Microsoft link.exe-
compatible linker if invoked as lld-link and as macOS's ld if invoked as ld.ld64. All these
targets are always supported however ld.lld was built, so you can always use ld.lld as a
native linker as well as a cross linker.
OPTIONS
--allow-multiple-definition
Do not error if a symbol is defined multiple times. The first definition will be
used.
--apply-dynamic-relocs
Apply link-time values for dynamic relocations.
--as-needed
Only set DT_NEEDED for shared libraries if used.
--auxiliary=value
Set the DT_AUXILIARY field to the specified name.
--Bdynamic, --dy
Link against shared libraries.
--Bstatic, --static, --dn
Do not link against shared libraries.
--Bsymbolic
Bind defined symbols locally.
--Bsymbolic-functions
Bind defined function symbols locally.
--build-id=value
Generate a build ID note. value may be one of fast, md5, sha1, tree, uuid,
0xhex-string, and none. tree is an alias for sha1. Build-IDs of type fast, md5,
sha1, and tree are calculated from the object contents. fast is not intended to be
cryptographically secure.
--build-id
Synonym for --build-id=fast.
--color-diagnostics=value
Use colors in diagnostics. value may be one of always, auto, and never. auto
enables color if and only if output is to a terminal.
--color-diagnostics
Alias for --color-diagnostics=auto.
--compress-debug-sections=value
Compress DWARF debug sections. value may be none or zlib.
--cref Output cross reference table.
--define-common, -d
Assign space to common symbols.
--defsym=symbol=expression
Define a symbol alias. expression may be another symbol or a linker script
expression. For example, ‘--defsym=foo=bar’ or ‘--defsym=foo=bar+0x100’.
--demangle
Demangle symbol names.
--disable-new-dtags
Disable new dynamic tags.
--discard-all, -x
Delete all local symbols.
--discard-locals, -X
Delete temporary local symbols.
--discard-none
Keep all symbols in the symbol table.
--dynamic-linker=value
Specify the dynamic linker to be used for a dynamically linked executable. This is
recorded in an ELF segment of type PT_INTERP.
--dynamic-list=file
Read a list of dynamic symbols from file.
--eh-frame-hdr
Request creation of .eh_frame_hdr section and PT_GNU_EH_FRAME segment header.
--emit-relocs, -q
Generate relocations in the output.
--enable-new-dtags
Enable new dynamic tags.
--end-lib
End a grouping of objects that should be treated as if they were together in an
archive.
--entry=entry
Name of entry point symbol.
--error-limit=value
Maximum number of errors to emit before stopping. A value of zero indicates that
there is no limit.
--error-unresolved-symbols
Report unresolved symbols as errors.
--execute-only
Mark executable sections unreadable. This option is currently only supported on
AArch64.
--exclude-libs=value
Exclude static libraries from automatic export.
--export-dynamic, -E
Put symbols in the dynamic symbol table.
--export-dynamic-symbol=symbol
Include symbol in the dynamic symbol table.
--fatal-warnings
Treat warnings as errors.
--filter=value, -F value
Set the DT_FILTER field to the specified value.
--fini=symbol
Specify a finalizer function.
--format=input-format, -b input-format
Specify the format of the inputs following this option. input-format may be one of
binary, elf, and default. default is a synonym for elf.
--gc-sections
Enable garbage collection of unused sections.
--gdb-index
Generate .gdb_index section.
--hash-style=value
Specify hash style. value may be sysv, gnu, or both. both is the default.
--help Print a help message.
--icf=all
Enable identical code folding.
--icf=safe
Enable safe identical code folding.
--icf=none
Disable identical code folding.
--image-base=value
Set the base address to value.
--init=symbol
Specify an initializer function.
--keep-unique=symbol
Do not fold symbol during ICF.
-l libName, --library=libName
Root name of library to use.
-L dir, --library-path=dir
Add a directory to the library search path.
--lto-aa-pipeline=value
AA pipeline to run during LTO. Used in conjunction with --lto-newpm-passes.
--lto-newpm-passes=value
Passes to run during LTO.
--lto-Oopt-level
Optimization level for LTO.
--lto-partitions=value
Number of LTO codegen partitions.
-m value
Set target emulation.
--Map=file, -M file
Print a link map to file.
--no-as-needed
Always set DT_NEEDED for shared libraries.
--no-color-diagnostics
Do not use colors in diagnostics.
--no-define-common
Do not assign space to common symbols.
--no-demangle
Do not demangle symbol names.
--no-dynamic-linker
Inhibit output of an .interp section.
--no-gc-sections
Disable garbage collection of unused sections.
--no-gnu-unique
Disable STB_GNU_UNIQUE symbol binding.
--no-rosegment
Do not put read-only non-executable sections in their own segment.
--no-threads
Do not run the linker multi-threaded.
--no-undefined-version
Report version scripts that refer undefined symbols.
--no-undefined
Report unresolved symbols even if the linker is creating a shared library.
--no-whole-archive
Restores the default behavior of loading archive members.
--no-pie
Do not create a position independent executable.
--noinhibit-exec
Retain the executable output file whenever it is still usable.
--nostdlib
Only search directories specified on the command line.
-o path
Write the output executable, library, or object to path. If not specified, a.out is
used as a default.
-Ovalue
Optimize output file size. value may be:
0 Disable string merging.
1 Enable string merging.
2 Enable string tail merging.
-O1 is the default.
--oformat=format
Specify the format for the output object file. The only supported format is binary,
which produces output with no ELF header.
--omagic, -N
Set the text and data sections to be readable and writable.
--opt-remarks-filename file
Write optimization remarks in YAML format to file.
--opt-remarks-with-hotness
Include hotness information in the optimization remarks file.
--pic-veneer
Always generate position independent thunks.
--pie Create a position independent executable.
--print-gc-sections
List removed unused sections.
--print-icf-sections
List identical folded sections.
--print-map
Print a link map to the standard output.
--push-state
Save the current state of --as-needed, --static, and --whole-archive.
--pop-state
Undo the effect of --push-state.
--relocatable, -r
Create relocatable object file.
--reproduce=value
Dump linker invocation and input files for debugging.
--retain-symbols-file=file
Retain only the symbols listed in the file.
--rpath=value, -R value
Add a DT_RUNPATH to the output.
--rsp-quoting=value
Quoting style for response files. The supported values are windows and posix.
--script=file, -T file
Read linker script from file.
--section-start=section=address
Set address of section.
--shared, --Bsharable
Build a shared object.
--soname=value, -h value
Set DT_SONAME to value.
--sort-section=value
Specifies sections sorting rule when linkerscript is used.
--start-lib
Start a grouping of objects that should be treated as if they were together in an
archive.
--strip-all, -s
Strip all symbols.
--strip-debug, -S
Strip debugging information.
--symbol-ordering-file=file
Lay out sections in the order specified by file.
--sysroot=value
Set the system root.
--target1-abs
Interpret R_ARM_TARGET1 as R_ARM_ABS32.
--target1-rel
Interpret R_ARM_TARGET1 as R_ARM_REL32.
--target2=type
Interpret R_ARM_TARGET2 as type, where type is one of rel, abs, or got-rel.
--Tbss=value
Same as --section-start with .bss as the sectionname.
--Tdata=value
Same as --section-start with .data as the sectionname.
--Ttext=value
Same as --section-start with .text as the sectionname.
--thinlto-cache-dir=value
Path to ThinLTO cached object file directory.
--thinlto-cache-policy=value
Pruning policy for the ThinLTO cache.
--thinlto-jobs=value
Number of ThinLTO jobs.
--threads
Run the linker multi-threaded. This option is enabled by default.
--trace
Print the names of the input files.
--trace-symbol=symbol, -y symbol
Trace references to symbol.
--undefined=symbol, -u symbol
Force symbol to be an undefined symbol during linking.
--unresolved-symbols=value
Determine how to handle unresolved symbols.
-v Display the version number and proceed with linking if object files are specified.
-V, --version
Display the version number and exit.
--verbose
Verbose mode.
--version-script=file
Read version script from file.
--warn-backrefs
Warn about reverse or cyclic dependencies to or between static archives. This can
be used to ensure linker invocation remains compatible with traditional Unix-like
linkers.
--warn-common
Warn about duplicate common symbols.
--warn-ifunc-textrel
Warn about using ifunc symbols in conjunction with text relocations. Older versions
of glibc library (2.28 and earlier) has a bug that causes the segment that includes
ifunc symbols to be marked as not executable when they are relocated. As a result,
although the program compiles and links successfully, it gives segmentation fault
when the instruction pointer reaches an ifunc symbol. Use -warn-ifunc-textrel to let
lld give a warning, if the code may include ifunc symbols, may do text relocations
and be linked with an older glibc version. Otherwise, there is no need to use it, as
the default value does not give a warning. This flag has been introduced in late
2018, has no counter part in ld and gold linkers, and may be removed in the future.
--warn-unresolved-symbols
Report unresolved symbols as warnings.
--whole-archive
Force load of all members in a static library.
--wrap=symbol
Use wrapper functions for symbol.
-z option
Linker option extensions.
execstack
Make the main stack executable. Stack permissions are recorded in the
PT_GNU_STACK segment.
global Sets the DF_1_GLOBAL flag in the DYNAMIC section. Different loaders can
decide how to handle this flag on their own.
initfirst
Sets the DF_1_INITFIRST flag to indicate the module should be initialized
first.
interpose
Set the DF_1_INTERPOSE flag to indicate to the runtime linker that the
object is an interposer. During symbol resolution interposers are searched
after the application but before other dependencies.
muldefs
Do not error if a symbol is defined multiple times. The first definition
will be used. This is a synonym for --allow-multiple-definition.
nocombreloc
Disable combining and sorting multiple relocation sections.
nocopyreloc
Disable the creation of copy relocations.
nodefaultlib
Set the DF_1_NODEFLIB flag to indicate that default library search paths
should be ignored.
nodelete
Set the DF_1_NODELETE flag to indicate that the object cannot be unloaded
from a process.
nodlopen
Set the DF_1_NOOPEN flag to indicate that the object may not be opened by
dlopen(3).
norelro
Do not indicate that portions of the object shold be mapped read-only after
initial relocation processing. The object will omit the PT_GNU_RELRO
segment.
notext Allow relocations against read-only segments. Sets the DT_TEXTREL flag in
the DYNAMIC section.
now Set the DF_BIND_NOW flag to indicate that the run-time loader should perform
all relocation processing as part of object initialization. By default
relocations may be performed on demand.
origin Set the DF_ORIGIN flag to indicate that the object requires $ORIGIN
processing.
retpolineplt
Emit retpoline format PLT entries as a mitigation for CVE-2017-5715.
rodynamic
Make the .dynamic section read-only. The DT_DEBUG tag will not be emitted.
stack-size=size
Set the main thread's stack size to size. The stack size is recorded as the
size of the size. PT_GNU_STACK program segment.
text Do not allow relocations against read-only segments. This is the default.
wxneeded
Create a PT_OPENBSD_WXNEEDED segment.
IMPLEMENTATION NOTES
ld.lld's handing of archive files (those with a .a file extension) is different from
traditional linkers used on Unix-like systems.
Traditional linkers maintain a set of undefined symbols during linking. The linker
processes each file in the order in which it appears on the command line, until the set of
undefined symbols becomes empty. An object file is linked into the output object when it is
encountered, with its undefined symbols added to the set. Upon encountering an archive file
a traditional linker searches the objects contained therein, and processes those that
satisfy symbols in the unresolved set.
Handling mutually dependent archives may be awkward when using a traditional linker.
Archive files may have to be specified multiple times, or the special command line options
--start-group and --end-group may be used to have the linker loop over the files in the
group until no new symbols are added to the set.
ld.lld records all symbols found in objects and archives as it iterates over command line
arguments. When ld.lld encounters an undefined symbol that can be resolved by an object
file contained in a previously processed archive file, it immediately extracts and links it
into the output object.
With certain archive inputs ld.lld may produce different results compared to traditional
linkers. In practice, large bodies of third party software have been linked with ld.lld
without material issues.
The --warn-backrefs option may be used to identify a linker invocation that may be
incompatible with traditional Unix-like linker behavior.