Provided by: lld-7_7.0.1-12_amd64 bug

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.

     These options are available:

     --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.

     --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.

     --pie   Create a position independent executable.

     --print-gc-sections
             List removed unused sections.

     --print-map
             Print a link map to the standard output.

     --push-state
             Save the current state of --as-needed, --static, and --while-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-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.

             initfirst
                     Sets the DF_1_INITFIRST flag to indicate the module should be initialized
                     first.

             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.

             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 indcate 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.