aarch64-linux-gnu-ld






ld − The GNU linker

ld [options] objfile ...

ld combines a number of object and archive files, relocates
their data and ties up symbol references. Usually the last
step in compiling a program is to run ld.

     ld accepts Linker Command Language files written in a
superset of AT&T’s Link Editor Command Language syntax, to
provide explicit and total control over the linking process.

     This man page does not describe the command language;
see the ld entry in "info" for full details on the command
language and on other aspects of the GNU linker.

     This version of ld uses the general purpose BFD
libraries to operate on object files. This allows ld to
read, combine, and write object files in many different
formats−−−for example, COFF or "a.out".  Different formats
may be linked together to produce any available kind of
object file.

     Aside from its flexibility, the GNU linker is more
helpful than other linkers in providing diagnostic
information.  Many linkers abandon execution immediately
upon encountering an error; whenever possible, ld continues
executing, allowing you to identify other errors (or, in
some cases, to get an output file in spite of the error).

     The GNU linker ld is meant to cover a broad range of
situations, and to be as compatible as possible with other
linkers.  As a result, you have many choices to control its
behavior.

The linker supports a plethora of command‐line options, but
in actual practice few of them are used in any particular
context.  For instance, a frequent use of ld is to link
standard Unix object files on a standard, supported Unix
system.  On such a system, to link a file "hello.o":

             ld −o <output> /lib/crt0.o hello.o −lc

     This tells ld to produce a file called output as the
result of linking the file "/lib/crt0.o" with "hello.o" and
the library "libc.a", which will come from the standard
search directories.  (See the discussion of the −l option
below.)

     Some of the command‐line options to ld may be specified
at any point in the command line.  However, options which
refer to files, such as −l or −T, cause the file to be read
at the point at which the option appears in the command
line, relative to the object files and other file options.









                             ‐2‐


Repeating non‐file options with a different argument will
either have no further effect, or override prior occurrences
(those further to the left on the command line) of that
option.  Options which may be meaningfully specified more
than once are noted in the descriptions below.

     Non‐option arguments are object files or archives which
are to be linked together.  They may follow, precede, or be
mixed in with command‐line options, except that an object
file argument may not be placed between an option and its
argument.

     Usually the linker is invoked with at least one object
file, but you can specify other forms of binary input files
using −l, −R, and the script command language.  If no binary
input files at all are specified, the linker does not
produce any output, and issues the message No input files.

     If the linker cannot recognize the format of an object
file, it will assume that it is a linker script.  A script
specified in this way augments the main linker script used
for the link (either the default linker script or the one
specified by using −T).  This feature permits the linker to
link against a file which appears to be an object or an
archive, but actually merely defines some symbol values, or
uses "INPUT" or "GROUP" to load other objects.  Specifying a
script in this way merely augments the main linker script,
with the extra commands placed after the main script; use
the −T option to replace the default linker script entirely,
but note the effect of the "INSERT" command.

     For options whose names are a single letter, option
arguments must either follow the option letter without
intervening whitespace, or be given as separate arguments
immediately following the option that requires them.

     For options whose names are multiple letters, either
one dash or two can precede the option name; for example,
−trace−symbol and −−trace−symbol are equivalent.
Note−−−there is one exception to this rule.  Multiple letter
options that start with a lower case ’o’ can only be
preceded by two dashes.  This is to reduce confusion with
the −o option.  So for example −omagic sets the output file
name to magic whereas −−omagic sets the NMAGIC flag on the
output.

     Arguments to multiple‐letter options must either be
separated from the option name by an equals sign, or be
given as separate arguments immediately following the option
that requires them.  For example, −−trace−symbol foo and
−−trace−symbol=foo are equivalent.  Unique abbreviations of
the names of multiple‐letter options are accepted.











                             ‐3‐


     Note−−−if the linker is being invoked indirectly, via a
compiler driver (e.g. gcc) then all the linker command‐line
options should be prefixed by −Wl, (or whatever is
appropriate for the particular compiler driver) like this:

               gcc −Wl,−−start−group foo.o bar.o −Wl,−−end−group

     This is important, because otherwise the compiler
driver program may silently drop the linker options,
resulting in a bad link.  Confusion may also arise when
passing options that require values through a driver, as the
use of a space between option and argument acts as a
separator, and causes the driver to pass only the option to
the linker and the argument to the compiler.  In this case,
it is simplest to use the joined forms of both single− and
multiple‐letter options, such as:

               gcc foo.o bar.o −Wl,−eENTRY −Wl,−Map=a.map

     Here is a table of the generic command‐line switches
accepted by the GNU linker:

@file
    Read command‐line options from file.  The options read
    are inserted in place of the original @file option.  If
    file does not exist, or cannot be read, then the option
    will be treated literally, and not removed.

    Options in file are separated by whitespace.  A
    whitespace character may be included in an option by
    surrounding the entire option in either single or double
    quotes.  Any character (including a backslash) may be
    included by prefixing the character to be included with
    a backslash.  The file may itself contain additional
    @file options; any such options will be processed
    recursively.

−a keyword
    This option is supported for HP/UX compatibility.  The
    keyword argument must be one of the strings archive,
    shared, or default.  −aarchive is functionally
    equivalent to −Bstatic, and the other two keywords are
    functionally equivalent to −Bdynamic.  This option may
    be used any number of times.

−−audit AUDITLIB
    Adds AUDITLIB to the "DT_AUDIT" entry of the dynamic
    section.  AUDITLIB is not checked for existence, nor
    will it use the DT_SONAME specified in the library.  If
    specified multiple times "DT_AUDIT" will contain a colon
    separated list of audit interfaces to use. If the linker
    finds an object with an audit entry while searching for
    shared libraries, it will add a corresponding
    "DT_DEPAUDIT" entry in the output file.  This option is









                             ‐4‐


    only meaningful on ELF platforms supporting the rtld‐
    audit interface.

−b input‐format

−−format=input‐format
    ld may be configured to support more than one kind of
    object file.  If your ld is configured this way, you can
    use the −b option to specify the binary format for input
    object files that follow this option on the command
    line.  Even when ld is configured to support alternative
    object formats, you don’t usually need to specify this,
    as ld should be configured to expect as a default input
    format the most usual format on each machine.  input‐
    format is a text string, the name of a particular format
    supported by the BFD libraries.  (You can list the
    available binary formats with objdump −i.)

    You may want to use this option if you are linking files
    with an unusual binary format.  You can also use −b to
    switch formats explicitly (when linking object files of
    different formats), by including −b input‐format before
    each group of object files in a particular format.

    The default format is taken from the environment
    variable "GNUTARGET".

    You can also define the input format from a script,
    using the command "TARGET";

−c MRI‐commandfile

−−mri−script=MRI‐commandfile
    For compatibility with linkers produced by MRI, ld
    accepts script files written in an alternate, restricted
    command language, described in the MRI Compatible Script
    Files section of GNU ld documentation.  Introduce MRI
    script files with the option −c; use the −T option to
    run linker scripts written in the general‐purpose ld
    scripting language.  If MRI‐cmdfile does not exist, ld
    looks for it in the directories specified by any −L
    options.

−d

−dc

−dp These three options are equivalent; multiple forms are
    supported for compatibility with other linkers.  They
    assign space to common symbols even if a relocatable
    output file is specified (with −r).  The script command
    "FORCE_COMMON_ALLOCATION" has the same effect.











                             ‐5‐


−−depaudit AUDITLIB

−P AUDITLIB
    Adds AUDITLIB to the "DT_DEPAUDIT" entry of the dynamic
    section.  AUDITLIB is not checked for existence, nor
    will it use the DT_SONAME specified in the library.  If
    specified multiple times "DT_DEPAUDIT" will contain a
    colon separated list of audit interfaces to use.  This
    option is only meaningful on ELF platforms supporting
    the rtld‐audit interface.  The −P option is provided for
    Solaris compatibility.

−e entry

−−entry=entry
    Use entry as the explicit symbol for beginning execution
    of your program, rather than the default entry point.
    If there is no symbol named entry, the linker will try
    to parse entry as a number, and use that as the entry
    address (the number will be interpreted in base 10; you
    may use a leading 0x for base 16, or a leading 0 for
    base 8).

−−exclude−libs lib,lib,...
    Specifies a list of archive libraries from which symbols
    should not be automatically exported.  The library names
    may be delimited by commas or colons.  Specifying
    "−−exclude−libs ALL" excludes symbols in all archive
    libraries from automatic export.  This option is
    available only for the i386 PE targeted port of the
    linker and for ELF targeted ports.  For i386 PE, symbols
    explicitly listed in a .def file are still exported,
    regardless of this option.  For ELF targeted ports,
    symbols affected by this option will be treated as
    hidden.

−−exclude−modules−for−implib module,module,...
    Specifies a list of object files or archive members,
    from which symbols should not be automatically exported,
    but which should be copied wholesale into the import
    library being generated during the link.  The module
    names may be delimited by commas or colons, and must
    match exactly the filenames used by ld to open the
    files; for archive members, this is simply the member
    name, but for object files the name listed must include
    and match precisely any path used to specify the input
    file on the linker’s command‐line.  This option is
    available only for the i386 PE targeted port of the
    linker.  Symbols explicitly listed in a .def file are
    still exported, regardless of this option.

−E











                             ‐6‐


−−export−dynamic

−−no−export−dynamic
    When creating a dynamically linked executable, using the
    −E option or the −−export−dynamic option causes the
    linker to add all symbols to the dynamic symbol table.
    The dynamic symbol table is the set of symbols which are
    visible from dynamic objects at run time.

    If you do not use either of these options (or use the
    −−no−export−dynamic option to restore the default
    behavior), the dynamic symbol table will normally
    contain only those symbols which are referenced by some
    dynamic object mentioned in the link.

    If you use "dlopen" to load a dynamic object which needs
    to refer back to the symbols defined by the program,
    rather than some other dynamic object, then you will
    probably need to use this option when linking the
    program itself.

    You can also use the dynamic list to control what
    symbols should be added to the dynamic symbol table if
    the output format supports it.  See the description of
    −−dynamic−list.

    Note that this option is specific to ELF targeted ports.
    PE targets support a similar function to export all
    symbols from a DLL or EXE; see the description of
    −−export−all−symbols below.

−EB Link big‐endian objects.  This affects the default
    output format.

−EL Link little‐endian objects.  This affects the default
    output format.

−f name

−−auxiliary=name
    When creating an ELF shared object, set the internal
    DT_AUXILIARY field to the specified name.  This tells
    the dynamic linker that the symbol table of the shared
    object should be used as an auxiliary filter on the
    symbol table of the shared object name.

    If you later link a program against this filter object,
    then, when you run the program, the dynamic linker will
    see the DT_AUXILIARY field.  If the dynamic linker
    resolves any symbols from the filter object, it will
    first check whether there is a definition in the shared
    object name.  If there is one, it will be used instead
    of the definition in the filter object.  The shared
    object name need not exist.  Thus the shared object name









                             ‐7‐


    may be used to provide an alternative implementation of
    certain functions, perhaps for debugging or for machine
    specific performance.

    This option may be specified more than once.  The
    DT_AUXILIARY entries will be created in the order in
    which they appear on the command line.

−F name

−−filter=name
    When creating an ELF shared object, set the internal
    DT_FILTER field to the specified name.  This tells the
    dynamic linker that the symbol table of the shared
    object which is being created should be used as a filter
    on the symbol table of the shared object name.

    If you later link a program against this filter object,
    then, when you run the program, the dynamic linker will
    see the DT_FILTER field.  The dynamic linker will
    resolve symbols according to the symbol table of the
    filter object as usual, but it will actually link to the
    definitions found in the shared object name.  Thus the
    filter object can be used to select a subset of the
    symbols provided by the object name.

    Some older linkers used the −F option throughout a
    compilation toolchain for specifying object‐file format
    for both input and output object files.  The GNU linker
    uses other mechanisms for this purpose: the −b,
    −−format, −−oformat options, the "TARGET" command in
    linker scripts, and the "GNUTARGET" environment
    variable.  The GNU linker will ignore the −F option when
    not creating an ELF shared object.

−fini=name
    When creating an ELF executable or shared object, call
    NAME when the executable or shared object is unloaded,
    by setting DT_FINI to the address of the function.  By
    default, the linker uses "_fini" as the function to
    call.

−g  Ignored.  Provided for compatibility with other tools.

−G value

−−gpsize=value
    Set the maximum size of objects to be optimized using
    the GP register to size.  This is only meaningful for
    object file formats such as MIPS ELF that support
    putting large and small objects into different sections.
    This is ignored for other object file formats.











                             ‐8‐


−h name

−soname=name
    When creating an ELF shared object, set the internal
    DT_SONAME field to the specified name.  When an
    executable is linked with a shared object which has a
    DT_SONAME field, then when the executable is run the
    dynamic linker will attempt to load the shared object
    specified by the DT_SONAME field rather than the using
    the file name given to the linker.

−i  Perform an incremental link (same as option −r).

−init=name
    When creating an ELF executable or shared object, call
    NAME when the executable or shared object is loaded, by
    setting DT_INIT to the address of the function.  By
    default, the linker uses "_init" as the function to
    call.

−l namespec

−−library=namespec
    Add the archive or object file specified by namespec to
    the list of files to link.  This option may be used any
    number of times.  If namespec is of the form :filename,
    ld will search the library path for a file called
    filename, otherwise it will search the library path for
    a file called libnamespec.a.

    On systems which support shared libraries, ld may also
    search for files other than libnamespec.a.
    Specifically, on ELF and SunOS systems, ld will search a
    directory for a library called libnamespec.so before
    searching for one called libnamespec.a.  (By convention,
    a ".so" extension indicates a shared library.)  Note
    that this behavior does not apply to :filename, which
    always specifies a file called filename.

    The linker will search an archive only once, at the
    location where it is specified on the command line.  If
    the archive defines a symbol which was undefined in some
    object which appeared before the archive on the command
    line, the linker will include the appropriate file(s)
    from the archive.  However, an undefined symbol in an
    object appearing later on the command line will not
    cause the linker to search the archive again.

    See the −( option for a way to force the linker to
    search archives multiple times.

    You may list the same archive multiple times on the
    command line.










                             ‐9‐


    This type of archive searching is standard for Unix
    linkers.  However, if you are using ld on AIX, note that
    it is different from the behaviour of the AIX linker.

−L searchdir

−−library−path=searchdir
    Add path searchdir to the list of paths that ld will
    search for archive libraries and ld control scripts.
    You may use this option any number of times.  The
    directories are searched in the order in which they are
    specified on the command line.  Directories specified on
    the command line are searched before the default
    directories.  All −L options apply to all −l options,
    regardless of the order in which the options appear.  −L
    options do not affect how ld searches for a linker
    script unless −T option is specified.

    If searchdir begins with "=" or $SYSROOT, then this
    prefix will be replaced by the sysroot prefix,
    controlled by the −−sysroot option, or specified when
    the linker is configured.

    The default set of paths searched (without being
    specified with −L) depends on which emulation mode ld is
    using, and in some cases also on how it was configured.

    The paths can also be specified in a link script with
    the "SEARCH_DIR" command.  Directories specified this
    way are searched at the point in which the linker script
    appears in the command line.

−m emulation
    Emulate the emulation linker.  You can list the
    available emulations with the −−verbose or −V options.

    If the −m option is not used, the emulation is taken
    from the "LDEMULATION" environment variable, if that is
    defined.

    Otherwise, the default emulation depends upon how the
    linker was configured.

−M

−−print−map
    Print a link map to the standard output.  A link map
    provides information about the link, including the
    following:

    •   Where object files are mapped into memory.

    •   How common symbols are allocated.










                            ‐10‐


    •   All archive members included in the link, with a
        mention of the symbol which caused the archive
        member to be brought in.

    •   The values assigned to symbols.

        Note − symbols whose values are computed by an
        expression which involves a reference to a previous
        value of the same symbol may not have correct result
        displayed in the link map.  This is because the
        linker discards intermediate results and only
        retains the final value of an expression.  Under
        such circumstances the linker will display the final
        value enclosed by square brackets.  Thus for example
        a linker script containing:

                   foo = 1
                   foo = foo * 4
                   foo = foo + 8

        will produce the following output in the link map if
        the −M option is used:

                   0x00000001                foo = 0x1
                   [0x0000000c]                foo = (foo * 0x4)
                   [0x0000000c]                foo = (foo + 0x8)

        See Expressions for more information about
        expressions in linker scripts.

    •   *<How GNU properties are merged.>

        When linker merges input .note.gnu.property sections
        into one output .note.gnu.property section, some
        properties are removed or updated, which are
        reported in the link map as

                Removed property 0xc0000002 to merge foo.o (0x1) and bar.o (not found)

        It indicates that property 0xc0000002 is removed
        from output when merging properties in  foo.o, whose
        property 0xc0000002 value is 0x1, and bar.o, which
        doesn’t have property 0xc0000002.

                Updated property 0xc0000002 (0x1) to merge foo.o (0x1) and bar.o (0x1)

        It indicates that property 0xc0010001 value is
        updated to 0x1 in output when merging properties in
        foo.o, whose 0xc0010001 property value is 0x1, and
        bar.o, whose 0xc0010001 property value is 0x1.

−n











                            ‐11‐


−−nmagic
    Turn off page alignment of sections, and disable linking
    against shared libraries.  If the output format supports
    Unix style magic numbers, mark the output as "NMAGIC".

−N

−−omagic
    Set the text and data sections to be readable and
    writable.  Also, do not page‐align the data segment, and
    disable linking against shared libraries.  If the output
    format supports Unix style magic numbers, mark the
    output as "OMAGIC". Note: Although a writable text
    section is allowed for PE‐COFF targets, it does not
    conform to the format specification published by
    Microsoft.

−−no−omagic
    This option negates most of the effects of the −N
    option.  It sets the text section to be read‐only, and
    forces the data segment to be page‐aligned.  Note − this
    option does not enable linking against shared libraries.
    Use −Bdynamic for this.

−o output

−−output=output
    Use output as the name for the program produced by ld;
    if this option is not specified, the name a.out is used
    by default.  The script command "OUTPUT" can also
    specify the output file name.

−O level
    If level is a numeric values greater than zero ld
    optimizes the output.  This might take significantly
    longer and therefore probably should only be enabled for
    the final binary.  At the moment this option only
    affects ELF shared library generation.  Future releases
    of the linker may make more use of this option.  Also
    currently there is no difference in the linker’s
    behaviour for different non‐zero values of this option.
    Again this may change with future releases.

−plugin name
    Involve a plugin in the linking process.  The name
    parameter is the absolute filename of the plugin.
    Usually this parameter is automatically added by the
    complier, when using link time optimization, but users
    can also add their own plugins if they so wish.

    Note that the location of the compiler originated
    plugins is different from the place where the ar, nm and
    ranlib programs search for their plugins.  In order for
    those commands to make use of a compiler based plugin it









                            ‐12‐


    must first be copied into the ${libdir}/bfd−plugins
    directory.  All gcc based linker plugins are backward
    compatible, so it is sufficient to just copy in the
    newest one.

−−push−state
    The −−push−state allows to preserve the current state of
    the flags which govern the input file handling so that
    they can all be restored with one corresponding
    −−pop−state option.

    The option which are covered are: −Bdynamic, −Bstatic,
    −dn, −dy, −call_shared, −non_shared, −static, −N, −n,
    −−whole−archive, −−no−whole−archive, −r, −Ur,
    −−copy−dt−needed−entries, −−no−copy−dt−needed−entries,
    −−as−needed, −−no−as−needed, and −a.

    One target for this option are specifications for pkg‐
    config.  When used with the −−libs option all possibly
    needed libraries are listed and then possibly linked
    with all the time.  It is better to return something as
    follows:

            −Wl,−−push−state,−−as−needed −libone −libtwo −Wl,−−pop−state

−−pop−state
    Undoes the effect of −−push−state, restores the previous
    values of the flags governing input file handling.

−q

−−emit−relocs
    Leave relocation sections and contents in fully linked
    executables.  Post link analysis and optimization tools
    may need this information in order to perform correct
    modifications of executables.  This results in larger
    executables.

    This option is currently only supported on ELF
    platforms.

−−force−dynamic
    Force the output file to have dynamic sections.  This
    option is specific to VxWorks targets.

−r

−−relocatable
    Generate relocatable output−−−i.e., generate an output
    file that can in turn serve as input to ld.  This is
    often called partial linking.  As a side effect, in
    environments that support standard Unix magic numbers,
    this option also sets the output file’s magic number to
    "OMAGIC".  If this option is not specified, an absolute









                            ‐13‐


    file is produced.  When linking C++ programs, this
    option will not resolve references to constructors; to
    do that, use −Ur.

    When an input file does not have the same format as the
    output file, partial linking is only supported if that
    input file does not contain any relocations.  Different
    output formats can have further restrictions; for
    example some "a.out"−based formats do not support
    partial linking with input files in other formats at
    all.

    This option does the same thing as −i.

−R filename

−−just−symbols=filename
    Read symbol names and their addresses from filename, but
    do not relocate it or include it in the output.  This
    allows your output file to refer symbolically to
    absolute locations of memory defined in other programs.
    You may use this option more than once.

    For compatibility with other ELF linkers, if the −R
    option is followed by a directory name, rather than a
    file name, it is treated as the −rpath option.

−s

−−strip−all
    Omit all symbol information from the output file.

−S

−−strip−debug
    Omit debugger symbol information (but not all symbols)
    from the output file.

−−strip−discarded

−−no−strip−discarded
    Omit (or do not omit) global symbols defined in
    discarded sections.  Enabled by default.

−t

−−trace
    Print the names of the input files as ld processes them.
    If −t is given twice then members within archives are
    also printed.  −t output is useful to generate a list of
    all the object files and scripts involved in linking,
    for example, when packaging files for a linker bug
    report.










                            ‐14‐


−T scriptfile

−−script=scriptfile
    Use scriptfile as the linker script.  This script
    replaces ld’s default linker script (rather than adding
    to it), so commandfile must specify everything necessary
    to describe the output file.    If scriptfile does not
    exist in the current directory, "ld" looks for it in the
    directories specified by any preceding −L options.
    Multiple −T options accumulate.

−dT scriptfile

−−default−script=scriptfile
    Use scriptfile as the default linker script.

    This option is similar to the −−script option except
    that processing of the script is delayed until after the
    rest of the command line has been processed.  This
    allows options placed after the −−default−script option
    on the command line to affect the behaviour of the
    linker script, which can be important when the linker
    command line cannot be directly controlled by the user.
    (eg because the command line is being constructed by
    another tool, such as gcc).

−u symbol

−−undefined=symbol
    Force symbol to be entered in the output file as an
    undefined symbol.  Doing this may, for example, trigger
    linking of additional modules from standard libraries.
    −u may be repeated with different option arguments to
    enter additional undefined symbols.  This option is
    equivalent to the "EXTERN" linker script command.

    If this option is being used to force additional modules
    to be pulled into the link, and if it is an error for
    the symbol to remain undefined, then the option
    −−require−defined should be used instead.

−−require−defined=symbol
    Require that symbol is defined in the output file.  This
    option is the same as option −−undefined except that if
    symbol is not defined in the output file then the linker
    will issue an error and exit.  The same effect can be
    achieved in a linker script by using "EXTERN", "ASSERT"
    and "DEFINED" together.  This option can be used
    multiple times to require additional symbols.

−Ur For anything other than C++ programs, this option is
    equivalent to −r: it generates relocatable
    output−−−i.e., an output file that can in turn serve as
    input to ld.  When linking C++ programs, −Ur does









                            ‐15‐


    resolve references to constructors, unlike −r.  It does
    not work to use −Ur on files that were themselves linked
    with −Ur; once the constructor table has been built, it
    cannot be added to.  Use −Ur only for the last partial
    link, and −r for the others.

−−orphan−handling=MODE
    Control how orphan sections are handled.  An orphan
    section is one not specifically mentioned in a linker
    script.

    MODE can have any of the following values:

    "place"
        Orphan sections are placed into a suitable output
        section following the strategy described in Orphan
        Sections.  The option −−unique also affects how
        sections are placed.

    "discard"
        All orphan sections are discarded, by placing them
        in the /DISCARD/ section.

    "warn"
        The linker will place the orphan section as for
        "place" and also issue a warning.

    "error"
        The linker will exit with an error if any orphan
        section is found.

        The default if −−orphan−handling is not given is
        "place".

−−unique[=SECTION]
    Creates a separate output section for every input
    section matching SECTION, or if the optional wildcard
    SECTION argument is missing, for every orphan input
    section.  An orphan section is one not specifically
    mentioned in a linker script.  You may use this option
    multiple times on the command line;  It prevents the
    normal merging of input sections with the same name,
    overriding output section assignments in a linker
    script.

−v

−−version

−V  Display the version number for ld.  The −V option also
    lists the supported emulations.

−x










                            ‐16‐


−−discard−all
    Delete all local symbols.

−X

−−discard−locals
    Delete all temporary local symbols.  (These symbols
    start with system‐specific local label prefixes,
    typically .L for ELF systems or L for traditional a.out
    systems.)

−y symbol

−−trace−symbol=symbol
    Print the name of each linked file in which symbol
    appears.  This option may be given any number of times.
    On many systems it is necessary to prepend an
    underscore.

    This option is useful when you have an undefined symbol
    in your link but don’t know where the reference is
    coming from.

−Y path
    Add path to the default library search path.  This
    option exists for Solaris compatibility.

−z keyword
    The recognized keywords are:

    bndplt
        Always generate BND prefix in PLT entries. Supported
        for Linux/x86_64.

    call−nop=prefix−addr

    call−nop=suffix−nop

    call−nop=prefix−byte

    call−nop=suffix−byte
        Specify the 1−byte "NOP" padding when transforming
        indirect call to a locally defined function, foo,
        via its GOT slot.  call−nop=prefix−addr generates
        "0x67 call foo".  call−nop=suffix−nop generates
        "call foo 0x90".  call−nop=prefix−byte generates
        "byte call foo".  call−nop=suffix−byte generates
        "call foo byte".  Supported for i386 and x86_64.

    combreloc

    nocombreloc
        Combine multiple dynamic relocation sections and
        sort to improve dynamic symbol lookup caching.  Do









                            ‐17‐


        not do this if nocombreloc.

    common

    nocommon
        Generate common symbols with STT_COMMON type during
        a relocatable link.  Use STT_OBJECT type if
        nocommon.

    common−page−size=value
        Set the page size most commonly used to value.
        Memory image layout will be optimized to minimize
        memory pages if the system is using pages of this
        size.

    defs
        Report unresolved symbol references from regular
        object files.  This is done even if the linker is
        creating a non‐symbolic shared library.  This option
        is the inverse of −z undefs.

    dynamic‐undefined‐weak

    nodynamic‐undefined‐weak
        Make undefined weak symbols dynamic when building a
        dynamic object, if they are referenced from a
        regular object file and not forced local by symbol
        visibility or versioning.  Do not make them dynamic
        if nodynamic‐undefined‐weak.  If neither option is
        given, a target may default to either option being
        in force, or make some other selection of undefined
        weak symbols dynamic.  Not all targets support these
        options.

    execstack
        Marks the object as requiring executable stack.

    global
        This option is only meaningful when building a
        shared object.  It makes the symbols defined by this
        shared object available for symbol resolution of
        subsequently loaded libraries.

    globalaudit
        This option is only meaningful when building a
        dynamic executable.  This option marks the
        executable as requiring global auditing by setting
        the "DF_1_GLOBAUDIT" bit in the "DT_FLAGS_1" dynamic
        tag.  Global auditing requires that any auditing
        library defined via the −−depaudit or −P command‐
        line options be run for all dynamic objects loaded
        by the application.











                            ‐18‐


    ibtplt
        Generate Intel Indirect Branch Tracking (IBT)
        enabled PLT entries.  Supported for Linux/i386 and
        Linux/x86_64.

    ibt Generate GNU_PROPERTY_X86_FEATURE_1_IBT in
        .note.gnu.property section to indicate compatibility
        with IBT.  This also implies ibtplt.  Supported for
        Linux/i386 and Linux/x86_64.

    initfirst
        This option is only meaningful when building a
        shared object.  It marks the object so that its
        runtime initialization will occur before the runtime
        initialization of any other objects brought into the
        process at the same time.  Similarly the runtime
        finalization of the object will occur after the
        runtime finalization of any other objects.

    interpose
        Specify that the dynamic loader should modify its
        symbol search order so that symbols in this shared
        library interpose all other shared libraries not so
        marked.

    lazy
        When generating an executable or shared library,
        mark it to tell the dynamic linker to defer function
        call resolution to the point when the function is
        called (lazy binding), rather than at load time.
        Lazy binding is the default.

    loadfltr
        Specify that the object’s filters be processed
        immediately at runtime.

    max−page−size=value
        Set the maximum memory page size supported to value.

    muldefs
        Allow multiple definitions.

    nocopyreloc
        Disable linker generated .dynbss variables used in
        place of variables defined in shared libraries.  May
        result in dynamic text relocations.

    nodefaultlib
        Specify that the dynamic loader search for
        dependencies of this object should ignore any
        default library search paths.

    nodelete
        Specify that the object shouldn’t be unloaded at









                            ‐19‐


        runtime.

    nodlopen
        Specify that the object is not available to
        "dlopen".

    nodump
        Specify that the object can not be dumped by
        "dldump".

    noexecstack
        Marks the object as not requiring executable stack.

    noextern‐protected‐data
        Don’t treat protected data symbols as external when
        building a shared library.  This option overrides
        the linker backend default.  It can be used to work
        around incorrect relocations against protected data
        symbols generated by compiler.  Updates on protected
        data symbols by another module aren’t visible to the
        resulting shared library.  Supported for i386 and
        x86−64.

    noreloc‐overflow
        Disable relocation overflow check.  This can be used
        to disable relocation overflow check if there will
        be no dynamic relocation overflow at run‐time.
        Supported for x86_64.

    now When generating an executable or shared library,
        mark it to tell the dynamic linker to resolve all
        symbols when the program is started, or when the
        shared library is loaded by dlopen, instead of
        deferring function call resolution to the point when
        the function is first called.

    origin
        Specify that the object requires $ORIGIN handling in
        paths.

    relro

    norelro
        Create an ELF "PT_GNU_RELRO" segment header in the
        object.  This specifies a memory segment that should
        be made read‐only after relocation, if supported.
        Specifying common‐page‐size smaller than the system
        page size will render this protection ineffective.
        Don’t create an ELF "PT_GNU_RELRO" segment if
        norelro.

    separate‐code











                            ‐20‐


    noseparate‐code
        Create separate code "PT_LOAD" segment header in the
        object.  This specifies a memory segment that should
        contain only instructions and must be in wholly
        disjoint pages from any other data.  Don’t create
        separate code "PT_LOAD" segment if noseparate‐code
        is used.

    shstk
        Generate GNU_PROPERTY_X86_FEATURE_1_SHSTK in
        .note.gnu.property section to indicate compatibility
        with Intel Shadow Stack.  Supported for Linux/i386
        and Linux/x86_64.

    stack−size=value
        Specify a stack size for an ELF "PT_GNU_STACK"
        segment.  Specifying zero will override any default
        non‐zero sized "PT_GNU_STACK" segment creation.

    text

    notext

    textoff
        Report an error if DT_TEXTREL is set, i.e., if the
        binary has dynamic relocations in read‐only
        sections.  Don’t report an error if notext or
        textoff.

    undefs
        Do not report unresolved symbol references from
        regular object files, either when creating an
        executable, or when creating a shared library.  This
        option is the inverse of −z defs.

        Other keywords are ignored for Solaris
        compatibility.

−( archives −)

−−start−group archives −−end−group
    The archives should be a list of archive files.  They
    may be either explicit file names, or −l options.

    The specified archives are searched repeatedly until no
    new undefined references are created.  Normally, an
    archive is searched only once in the order that it is
    specified on the command line.  If a symbol in that
    archive is needed to resolve an undefined symbol
    referred to by an object in an archive that appears
    later on the command line, the linker would not be able
    to resolve that reference.  By grouping the archives,
    they all be searched repeatedly until all possible
    references are resolved.









                            ‐21‐


    Using this option has a significant performance cost.
    It is best to use it only when there are unavoidable
    circular references between two or more archives.

−−accept−unknown−input−arch

−−no−accept−unknown−input−arch
    Tells the linker to accept input files whose
    architecture cannot be recognised.  The assumption is
    that the user knows what they are doing and deliberately
    wants to link in these unknown input files.  This was
    the default behaviour of the linker, before release
    2.14.  The default behaviour from release 2.14 onwards
    is to reject such input files, and so the
    −−accept−unknown−input−arch option has been added to
    restore the old behaviour.

−−as−needed

−−no−as−needed
    This option affects ELF DT_NEEDED tags for dynamic
    libraries mentioned on the command line after the
    −−as−needed option.  Normally the linker will add a
    DT_NEEDED tag for each dynamic library mentioned on the
    command line, regardless of whether the library is
    actually needed or not.  −−as−needed causes a DT_NEEDED
    tag to only be emitted for a library that at that point
    in the link satisfies a non‐weak undefined symbol
    reference from a regular object file or, if the library
    is not found in the DT_NEEDED lists of other needed
    libraries, a non‐weak undefined symbol reference from
    another needed dynamic library.  Object files or
    libraries appearing on the command line after the
    library in question do not affect whether the library is
    seen as needed.  This is similar to the rules for
    extraction of object files from archives.
    −−no−as−needed restores the default behaviour.

−−add−needed

−−no−add−needed
    These two options have been deprecated because of the
    similarity of their names to the −−as−needed and
    −−no−as−needed options.  They have been replaced by
    −−copy−dt−needed−entries and
    −−no−copy−dt−needed−entries.

−assert keyword
    This option is ignored for SunOS compatibility.

−Bdynamic

−dy










                            ‐22‐


−call_shared
    Link against dynamic libraries.  This is only meaningful
    on platforms for which shared libraries are supported.
    This option is normally the default on such platforms.
    The different variants of this option are for
    compatibility with various systems.  You may use this
    option multiple times on the command line: it affects
    library searching for −l options which follow it.

−Bgroup
    Set the "DF_1_GROUP" flag in the "DT_FLAGS_1" entry in
    the dynamic section.  This causes the runtime linker to
    handle lookups in this object and its dependencies to be
    performed only inside the group.
    −−unresolved−symbols=report−all is implied.  This option
    is only meaningful on ELF platforms which support shared
    libraries.

−Bstatic

−dn

−non_shared

−static
    Do not link against shared libraries.  This is only
    meaningful on platforms for which shared libraries are
    supported.  The different variants of this option are
    for compatibility with various systems.  You may use
    this option multiple times on the command line: it
    affects library searching for −l options which follow
    it.  This option also implies
    −−unresolved−symbols=report−all.  This option can be
    used with −shared.  Doing so means that a shared library
    is being created but that all of the library’s external
    references must be resolved by pulling in entries from
    static libraries.

−Bsymbolic
    When creating a shared library, bind references to
    global symbols to the definition within the shared
    library, if any.  Normally, it is possible for a program
    linked against a shared library to override the
    definition within the shared library.  This option can
    also be used with the −−export−dynamic option, when
    creating a position independent executable, to bind
    references to global symbols to the definition within
    the executable.  This option is only meaningful on ELF
    platforms which support shared libraries and position
    independent executables.

−Bsymbolic−functions
    When creating a shared library, bind references to
    global function symbols to the definition within the









                            ‐23‐


    shared library, if any.  This option can also be used
    with the −−export−dynamic option, when creating a
    position independent executable, to bind references to
    global function symbols to the definition within the
    executable.  This option is only meaningful on ELF
    platforms which support shared libraries and position
    independent executables.

−−dynamic−list=dynamic‐list‐file
    Specify the name of a dynamic list file to the linker.
    This is typically used when creating shared libraries to
    specify a list of global symbols whose references
    shouldn’t be bound to the definition within the shared
    library, or creating dynamically linked executables to
    specify a list of symbols which should be added to the
    symbol table in the executable.  This option is only
    meaningful on ELF platforms which support shared
    libraries.

    The format of the dynamic list is the same as the
    version node without scope and node name.  See VERSION
    for more information.

−−dynamic−list−data
    Include all global data symbols to the dynamic list.

−−dynamic−list−cpp−new
    Provide the builtin dynamic list for C++ operator new
    and delete.  It is mainly useful for building shared
    libstdc++.

−−dynamic−list−cpp−typeinfo
    Provide the builtin dynamic list for C++ runtime type
    identification.

−−check−sections

−−no−check−sections
    Asks the linker not to check section addresses after
    they have been assigned to see if there are any
    overlaps.  Normally the linker will perform this check,
    and if it finds any overlaps it will produce suitable
    error messages.  The linker does know about, and does
    make allowances for sections in overlays.  The default
    behaviour can be restored by using the command‐line
    switch −−check−sections.  Section overlap is not usually
    checked for relocatable links.  You can force checking
    in that case by using the −−check−sections option.

−−copy−dt−needed−entries

−−no−copy−dt−needed−entries
    This option affects the treatment of dynamic libraries
    referred to by DT_NEEDED tags inside ELF dynamic









                            ‐24‐


    libraries mentioned on the command line.  Normally the
    linker won’t add a DT_NEEDED tag to the output binary
    for each library mentioned in a DT_NEEDED tag in an
    input dynamic library.  With −−copy−dt−needed−entries
    specified on the command line however any dynamic
    libraries that follow it will have their DT_NEEDED
    entries added.  The default behaviour can be restored
    with −−no−copy−dt−needed−entries.

    This option also has an effect on the resolution of
    symbols in dynamic libraries.  With
    −−copy−dt−needed−entries dynamic libraries mentioned on
    the command line will be recursively searched, following
    their DT_NEEDED tags to other libraries, in order to
    resolve symbols required by the output binary.  With the
    default setting however the searching of dynamic
    libraries that follow it will stop with the dynamic
    library itself.  No DT_NEEDED links will be traversed to
    resolve symbols.

−−cref
    Output a cross reference table.  If a linker map file is
    being generated, the cross reference table is printed to
    the map file.  Otherwise, it is printed on the standard
    output.

    The format of the table is intentionally simple, so that
    it may be easily processed by a script if necessary.
    The symbols are printed out, sorted by name.  For each
    symbol, a list of file names is given.  If the symbol is
    defined, the first file listed is the location of the
    definition.  If the symbol is defined as a common value
    then any files where this happens appear next.  Finally
    any files that reference the symbol are listed.

−−no−define−common
    This option inhibits the assignment of addresses to
    common symbols.  The script command
    "INHIBIT_COMMON_ALLOCATION" has the same effect.

    The −−no−define−common option allows decoupling the
    decision to assign addresses to Common symbols from the
    choice of the output file type; otherwise a non‐
    Relocatable output type forces assigning addresses to
    Common symbols.  Using −−no−define−common allows Common
    symbols that are referenced from a shared library to be
    assigned addresses only in the main program.  This
    eliminates the unused duplicate space in the shared
    library, and also prevents any possible confusion over
    resolving to the wrong duplicate when there are many
    dynamic modules with specialized search paths for
    runtime symbol resolution.











                            ‐25‐


−−force−group−allocation
    This option causes the linker to place section group
    members like normal input sections, and to delete the
    section groups.  This is the default behaviour for a
    final link but this option can be used to change the
    behaviour of a relocatable link (−r).  The script
    command "FORCE_GROUP_ALLOCATION" has the same effect.

−−defsym=symbol=expression
    Create a global symbol in the output file, containing
    the absolute address given by expression.  You may use
    this option as many times as necessary to define
    multiple symbols in the command line.  A limited form of
    arithmetic is supported for the expression in this
    context: you may give a hexadecimal constant or the name
    of an existing symbol, or use "+" and "−" to add or
    subtract hexadecimal constants or symbols.  If you need
    more elaborate expressions, consider using the linker
    command language from a script.  Note: there should be
    no white space between symbol, the equals sign ("="),
    and expression.

−−demangle[=style]

−−no−demangle
    These options control whether to demangle symbol names
    in error messages and other output.  When the linker is
    told to demangle, it tries to present symbol names in a
    readable fashion: it strips leading underscores if they
    are used by the object file format, and converts C++
    mangled symbol names into user readable names.
    Different compilers have different mangling styles.  The
    optional demangling style argument can be used to choose
    an appropriate demangling style for your compiler.  The
    linker will demangle by default unless the environment
    variable COLLECT_NO_DEMANGLE is set.  These options may
    be used to override the default.

−Ifile

−−dynamic−linker=file
    Set the name of the dynamic linker.  This is only
    meaningful when generating dynamically linked ELF
    executables.  The default dynamic linker is normally
    correct; don’t use this unless you know what you are
    doing.

−−no−dynamic−linker
    When producing an executable file, omit the request for
    a dynamic linker to be used at load‐time.  This is only
    meaningful for ELF executables that contain dynamic
    relocations, and usually requires entry point code that
    is capable of processing these relocations.










                            ‐26‐


−−embedded−relocs
    This option is similar to the −−emit−relocs option
    except that the relocs are stored in a target specific
    section.  This option is only supported by the BFIN,
    CR16 and M68K targets.

−−disable−multiple−abs−defs
    Do not allow multiple definitions with symbols included
    in filename invoked by −R or −−just−symbols

−−fatal−warnings

−−no−fatal−warnings
    Treat all warnings as errors.  The default behaviour can
    be restored with the option −−no−fatal−warnings.

−−force−exe−suffix
    Make sure that an output file has a .exe suffix.

    If a successfully built fully linked output file does
    not have a ".exe" or ".dll" suffix, this option forces
    the linker to copy the output file to one of the same
    name with a ".exe" suffix. This option is useful when
    using unmodified Unix makefiles on a Microsoft Windows
    host, since some versions of Windows won’t run an image
    unless it ends in a ".exe" suffix.

−−gc−sections

−−no−gc−sections
    Enable garbage collection of unused input sections.  It
    is ignored on targets that do not support this option.
    The default behaviour (of not performing this garbage
    collection) can be restored by specifying
    −−no−gc−sections on the command line.  Note that garbage
    collection for COFF and PE format targets is supported,
    but the implementation is currently considered to be
    experimental.

    −−gc−sections decides which input sections are used by
    examining symbols and relocations.  The section
    containing the entry symbol and all sections containing
    symbols undefined on the command‐line will be kept, as
    will sections containing symbols referenced by dynamic
    objects.  Note that when building shared libraries, the
    linker must assume that any visible symbol is
    referenced.  Once this initial set of sections has been
    determined, the linker recursively marks as used any
    section referenced by their relocations.  See −−entry,
    −−undefined, and −−gc−keep−exported.

    This option can be set when doing a partial link
    (enabled with option −r).  In this case the root of
    symbols kept must be explicitly specified either by one









                            ‐27‐


    of the options −−entry, −−undefined, or
    −−gc−keep−exported or by a "ENTRY" command in the linker
    script.

−−print−gc−sections

−−no−print−gc−sections
    List all sections removed by garbage collection.  The
    listing is printed on stderr.  This option is only
    effective if garbage collection has been enabled via the
    −−gc−sections) option.  The default behaviour (of not
    listing the sections that are removed) can be restored
    by specifying −−no−print−gc−sections on the command
    line.

−−gc−keep−exported
    When −−gc−sections is enabled, this option prevents
    garbage collection of unused input sections that contain
    global symbols having default or protected visibility.
    This option is intended to be used for executables where
    unreferenced sections would otherwise be garbage
    collected regardless of the external visibility of
    contained symbols.  Note that this option has no effect
    when linking shared objects since it is already the
    default behaviour.  This option is only supported for
    ELF format targets.

−−print−output−format
    Print the name of the default output format (perhaps
    influenced by other command‐line options).  This is the
    string that would appear in an "OUTPUT_FORMAT" linker
    script command.

−−print−memory−usage
    Print used size, total size and used size of memory
    regions created with the MEMORY command.  This is useful
    on embedded targets to have a quick view of amount of
    free memory.  The format of the output has one headline
    and one line per region.  It is both human readable and
    easily parsable by tools.  Here is an example of an
    output:

            Memory region         Used Size  Region Size  %age Used
                         ROM:        256 KB         1 MB     25.00%
                         RAM:          32 B         2 GB      0.00%

−−help
    Print a summary of the command‐line options on the
    standard output and exit.

−−target−help
    Print a summary of all target specific options on the
    standard output and exit.










                            ‐28‐


−Map=mapfile
    Print a link map to the file mapfile.  See the
    description of the −M option, above.

−−no−keep−memory
    ld normally optimizes for speed over memory usage by
    caching the symbol tables of input files in memory.
    This option tells ld to instead optimize for memory
    usage, by rereading the symbol tables as necessary.
    This may be required if ld runs out of memory space
    while linking a large executable.

−−no−undefined

−z defs
    Report unresolved symbol references from regular object
    files.  This is done even if the linker is creating a
    non‐symbolic shared library.  The switch
    −−[no−]allow−shlib−undefined controls the behaviour for
    reporting unresolved references found in shared
    libraries being linked in.

    The effects of this option can be reverted by using "−z
    undefs".

−−allow−multiple−definition

−z muldefs
    Normally when a symbol is defined multiple times, the
    linker will report a fatal error. These options allow
    multiple definitions and the first definition will be
    used.

−−allow−shlib−undefined

−−no−allow−shlib−undefined
    Allows or disallows undefined symbols in shared
    libraries.  This switch is similar to −−no−undefined
    except that it determines the behaviour when the
    undefined symbols are in a shared library rather than a
    regular object file.  It does not affect how undefined
    symbols in regular object files are handled.

    The default behaviour is to report errors for any
    undefined symbols referenced in shared libraries if the
    linker is being used to create an executable, but to
    allow them if the linker is being used to create a
    shared library.

    The reasons for allowing undefined symbol references in
    shared libraries specified at link time are that:

    •   A shared library specified at link time may not be
        the same as the one that is available at load time,









                            ‐29‐


        so the symbol might actually be resolvable at load
        time.

    •   There are some operating systems, eg BeOS and HPPA,
        where undefined symbols in shared libraries are
        normal.

        The BeOS kernel for example patches shared libraries
        at load time to select whichever function is most
        appropriate for the current architecture.  This is
        used, for example, to dynamically select an
        appropriate memset function.

−−no−undefined−version
    Normally when a symbol has an undefined version, the
    linker will ignore it. This option disallows symbols
    with undefined version and a fatal error will be issued
    instead.

−−default−symver
    Create and use a default symbol version (the soname) for
    unversioned exported symbols.

−−default−imported−symver
    Create and use a default symbol version (the soname) for
    unversioned imported symbols.

−−no−warn−mismatch
    Normally ld will give an error if you try to link
    together input files that are mismatched for some
    reason, perhaps because they have been compiled for
    different processors or for different endiannesses.
    This option tells ld that it should silently permit such
    possible errors.  This option should only be used with
    care, in cases when you have taken some special action
    that ensures that the linker errors are inappropriate.

−−no−warn−search−mismatch
    Normally ld will give a warning if it finds an
    incompatible library during a library search.  This
    option silences the warning.

−−no−whole−archive
    Turn off the effect of the −−whole−archive option for
    subsequent archive files.

−−noinhibit−exec
    Retain the executable output file whenever it is still
    usable.  Normally, the linker will not produce an output
    file if it encounters errors during the link process; it
    exits without writing an output file when it issues any
    error whatsoever.











                            ‐30‐


−nostdlib
    Only search library directories explicitly specified on
    the command line.  Library directories specified in
    linker scripts (including linker scripts specified on
    the command line) are ignored.

−−oformat=output‐format
    ld may be configured to support more than one kind of
    object file.  If your ld is configured this way, you can
    use the −−oformat option to specify the binary format
    for the output object file.  Even when ld is configured
    to support alternative object formats, you don’t usually
    need to specify this, as ld should be configured to
    produce as a default output format the most usual format
    on each machine.  output‐format is a text string, the
    name of a particular format supported by the BFD
    libraries.  (You can list the available binary formats
    with objdump −i.)  The script command "OUTPUT_FORMAT"
    can also specify the output format, but this option
    overrides it.

−−out−implib file
    Create an import library in file corresponding to the
    executable the linker is generating (eg. a DLL or ELF
    program).  This import library (which should be called
    "*.dll.a" or "*.a" for DLLs) may be used to link clients
    against the generated executable; this behaviour makes
    it possible to skip a separate import library creation
    step (eg. "dlltool" for DLLs).  This option is only
    available for the i386 PE and ELF targetted ports of the
    linker.

−pie

−−pic−executable
    Create a position independent executable.  This is
    currently only supported on ELF platforms.  Position
    independent executables are similar to shared libraries
    in that they are relocated by the dynamic linker to the
    virtual address the OS chooses for them (which can vary
    between invocations).  Like normal dynamically linked
    executables they can be executed and symbols defined in
    the executable cannot be overridden by shared libraries.

−qmagic
    This option is ignored for Linux compatibility.

−Qy This option is ignored for SVR4 compatibility.

−−relax

−−no−relax
    An option with machine dependent effects.  This option
    is only supported on a few targets.









                            ‐31‐


    On some platforms the −−relax option performs target
    specific, global optimizations that become possible when
    the linker resolves addressing in the program, such as
    relaxing address modes, synthesizing new instructions,
    selecting shorter version of current instructions, and
    combining constant values.

    On some platforms these link time global optimizations
    may make symbolic debugging of the resulting executable
    impossible.  This is known to be the case for the
    Matsushita MN10200 and MN10300 family of processors.

    On platforms where this is not supported, −−relax is
    accepted, but ignored.

    On platforms where −−relax is accepted the option
    −−no−relax can be used to disable the feature.

−−retain−symbols−file=filename
    Retain only the symbols listed in the file filename,
    discarding all others.  filename is simply a flat file,
    with one symbol name per line.  This option is
    especially useful in environments (such as VxWorks)
    where a large global symbol table is accumulated
    gradually, to conserve run‐time memory.

    −−retain−symbols−file does not discard undefined
    symbols, or symbols needed for relocations.

    You may only specify −−retain−symbols−file once in the
    command line.  It overrides −s and −S.

−rpath=dir
    Add a directory to the runtime library search path.
    This is used when linking an ELF executable with shared
    objects.  All −rpath arguments are concatenated and
    passed to the runtime linker, which uses them to locate
    shared objects at runtime.  The −rpath option is also
    used when locating shared objects which are needed by
    shared objects explicitly included in the link; see the
    description of the −rpath−link option.  If −rpath is not
    used when linking an ELF executable, the contents of the
    environment variable "LD_RUN_PATH" will be used if it is
    defined.

    The −rpath option may also be used on SunOS.  By
    default, on SunOS, the linker will form a runtime search
    path out of all the −L options it is given.  If a −rpath
    option is used, the runtime search path will be formed
    exclusively using the −rpath options, ignoring the −L
    options.  This can be useful when using gcc, which adds
    many −L options which may be on NFS mounted file
    systems.










                            ‐32‐


    For compatibility with other ELF linkers, if the −R
    option is followed by a directory name, rather than a
    file name, it is treated as the −rpath option.

−rpath−link=dir
    When using ELF or SunOS, one shared library may require
    another.  This happens when an "ld −shared" link
    includes a shared library as one of the input files.

    When the linker encounters such a dependency when doing
    a non‐shared, non‐relocatable link, it will
    automatically try to locate the required shared library
    and include it in the link, if it is not included
    explicitly.  In such a case, the −rpath−link option
    specifies the first set of directories to search.  The
    −rpath−link option may specify a sequence of directory
    names either by specifying a list of names separated by
    colons, or by appearing multiple times.

    The tokens $ORIGIN and $LIB can appear in these search
    directories.  They will be replaced by the full path to
    the directory containing the program or shared object in
    the case of $ORIGIN and either lib − for 32−bit binaries
    − or lib64 − for 64−bit binaries − in the case of $LIB.

    The alternative form of these tokens − ${ORIGIN} and
    ${LIB} can also be used.  The token $PLATFORM is not
    supported.

    This option should be used with caution as it overrides
    the search path that may have been hard compiled into a
    shared library. In such a case it is possible to use
    unintentionally a different search path than the runtime
    linker would do.

    The linker uses the following search paths to locate
    required shared libraries:

    1.  Any directories specified by −rpath−link options.

    2.  Any directories specified by −rpath options.  The
        difference between −rpath and −rpath−link is that
        directories specified by −rpath options are included
        in the executable and used at runtime, whereas the
        −rpath−link option is only effective at link time.
        Searching −rpath in this way is only supported by
        native linkers and cross linkers which have been
        configured with the −−with−sysroot option.

    3.  On an ELF system, for native linkers, if the −rpath
        and −rpath−link options were not used, search the
        contents of the environment variable "LD_RUN_PATH".











                            ‐33‐


    4.  On SunOS, if the −rpath option was not used, search
        any directories specified using −L options.

    5.  For a native linker, search the contents of the
        environment variable "LD_LIBRARY_PATH".

    6.  For a native ELF linker, the directories in
        "DT_RUNPATH" or "DT_RPATH" of a shared library are
        searched for shared libraries needed by it. The
        "DT_RPATH" entries are ignored if "DT_RUNPATH"
        entries exist.

    7.  The default directories, normally /lib and /usr/lib.

    8.  For a native linker on an ELF system, if the file
        /etc/ld.so.conf exists, the list of directories
        found in that file.

        If the required shared library is not found, the
        linker will issue a warning and continue with the
        link.

−shared

−Bshareable
    Create a shared library.  This is currently only
    supported on ELF, XCOFF and SunOS platforms.  On SunOS,
    the linker will automatically create a shared library if
    the −e option is not used and there are undefined
    symbols in the link.

−−sort−common

−−sort−common=ascending

−−sort−common=descending
    This option tells ld to sort the common symbols by
    alignment in ascending or descending order when it
    places them in the appropriate output sections.  The
    symbol alignments considered are sixteen‐byte or larger,
    eight‐byte, four‐byte, two‐byte, and one‐byte. This is
    to prevent gaps between symbols due to alignment
    constraints.  If no sorting order is specified, then
    descending order is assumed.

−−sort−section=name
    This option will apply "SORT_BY_NAME" to all wildcard
    section patterns in the linker script.

−−sort−section=alignment
    This option will apply "SORT_BY_ALIGNMENT" to all
    wildcard section patterns in the linker script.











                            ‐34‐


−−spare−dynamic−tags=count
    This option specifies the number of empty slots to leave
    in the .dynamic section of ELF shared objects.  Empty
    slots may be needed by post processing tools, such as
    the prelinker.  The default is 5.

−−split−by−file[=size]
    Similar to −−split−by−reloc but creates a new output
    section for each input file when size is reached.  size
    defaults to a size of 1 if not given.

−−split−by−reloc[=count]
    Tries to creates extra sections in the output file so
    that no single output section in the file contains more
    than count relocations.  This is useful when generating
    huge relocatable files for downloading into certain real
    time kernels with the COFF object file format; since
    COFF cannot represent more than 65535 relocations in a
    single section.  Note that this will fail to work with
    object file formats which do not support arbitrary
    sections.  The linker will not split up individual input
    sections for redistribution, so if a single input
    section contains more than count relocations one output
    section will contain that many relocations.  count
    defaults to a value of 32768.

−−stats
    Compute and display statistics about the operation of
    the linker, such as execution time and memory usage.

−−sysroot=directory
    Use directory as the location of the sysroot, overriding
    the configure‐time default.  This option is only
    supported by linkers that were configured using
    −−with−sysroot.

−−task−link
    This is used by COFF/PE based targets to create a task‐
    linked object file where all of the global symbols have
    been converted to statics.

−−traditional−format
    For some targets, the output of ld is different in some
    ways from the output of some existing linker.  This
    switch requests ld to use the traditional format
    instead.

    For example, on SunOS, ld combines duplicate entries in
    the symbol string table.  This can reduce the size of an
    output file with full debugging information by over 30
    percent.  Unfortunately, the SunOS "dbx" program can not
    read the resulting program ("gdb" has no trouble).  The
    −−traditional−format switch tells ld to not combine
    duplicate entries.









                            ‐35‐


−−section−start=sectionname=org
    Locate a section in the output file at the absolute
    address given by org.  You may use this option as many
    times as necessary to locate multiple sections in the
    command line.  org must be a single hexadecimal integer;
    for compatibility with other linkers, you may omit the
    leading 0x usually associated with hexadecimal values.
    Note: there should be no white space between
    sectionname, the equals sign ("="), and org.

−Tbss=org

−Tdata=org

−Ttext=org
    Same as −−section−start, with ".bss", ".data" or ".text"
    as the sectionname.

−Ttext−segment=org
    When creating an ELF executable, it will set the address
    of the first byte of the text segment.

−Trodata−segment=org
    When creating an ELF executable or shared object for a
    target where the read‐only data is in its own segment
    separate from the executable text, it will set the
    address of the first byte of the read‐only data segment.

−Tldata−segment=org
    When creating an ELF executable or shared object for
    x86−64 medium memory model, it will set the address of
    the first byte of the ldata segment.

−−unresolved−symbols=method
    Determine how to handle unresolved symbols.  There are
    four possible values for method:

    ignore‐all
        Do not report any unresolved symbols.

    report‐all
        Report all unresolved symbols.  This is the default.

    ignore‐in‐object‐files
        Report unresolved symbols that are contained in
        shared libraries, but ignore them if they come from
        regular object files.

    ignore‐in‐shared‐libs
        Report unresolved symbols that come from regular
        object files, but ignore them if they come from
        shared libraries.  This can be useful when creating
        a dynamic binary and it is known that all the shared
        libraries that it should be referencing are included









                            ‐36‐


        on the linker’s command line.

        The behaviour for shared libraries on their own can
        also be controlled by the
        −−[no−]allow−shlib−undefined option.

        Normally the linker will generate an error message
        for each reported unresolved symbol but the option
        −−warn−unresolved−symbols can change this to a
        warning.

−−dll−verbose

−−verbose[=NUMBER]
    Display the version number for ld and list the linker
    emulations supported.  Display which input files can and
    cannot be opened.  Display the linker script being used
    by the linker. If the optional NUMBER argument > 1,
    plugin symbol status will also be displayed.

−−version−script=version‐scriptfile
    Specify the name of a version script to the linker.
    This is typically used when creating shared libraries to
    specify additional information about the version
    hierarchy for the library being created.  This option is
    only fully supported on ELF platforms which support
    shared libraries; see VERSION.  It is partially
    supported on PE platforms, which can use version scripts
    to filter symbol visibility in auto‐export mode: any
    symbols marked local in the version script will not be
    exported.

−−warn−common
    Warn when a common symbol is combined with another
    common symbol or with a symbol definition.  Unix linkers
    allow this somewhat sloppy practice, but linkers on some
    other operating systems do not.  This option allows you
    to find potential problems from combining global
    symbols.  Unfortunately, some C libraries use this
    practice, so you may get some warnings about symbols in
    the libraries as well as in your programs.

    There are three kinds of global symbols, illustrated
    here by C examples:

    int i = 1;
        A definition, which goes in the initialized data
        section of the output file.

    extern int i;
        An undefined reference, which does not allocate
        space.  There must be either a definition or a
        common symbol for the variable somewhere.










                            ‐37‐


    int i;
        A common symbol.  If there are only (one or more)
        common symbols for a variable, it goes in the
        uninitialized data area of the output file.  The
        linker merges multiple common symbols for the same
        variable into a single symbol.  If they are of
        different sizes, it picks the largest size.  The
        linker turns a common symbol into a declaration, if
        there is a definition of the same variable.

        The −−warn−common option can produce five kinds of
        warnings.  Each warning consists of a pair of lines:
        the first describes the symbol just encountered, and
        the second describes the previous symbol encountered
        with the same name.  One or both of the two symbols
        will be a common symbol.

    1.  Turning a common symbol into a reference, because
        there is already a definition for the symbol.

                <file>(<section>): warning: common of `<symbol>'
                   overridden by definition
                <file>(<section>): warning: defined here

    2.  Turning a common symbol into a reference, because a
        later definition for the symbol is encountered.
        This is the same as the previous case, except that
        the symbols are encountered in a different order.

                <file>(<section>): warning: definition of `<symbol>'
                   overriding common
                <file>(<section>): warning: common is here

    3.  Merging a common symbol with a previous same‐sized
        common symbol.

                <file>(<section>): warning: multiple common
                   of `<symbol>'
                <file>(<section>): warning: previous common is here

    4.  Merging a common symbol with a previous larger
        common symbol.

                <file>(<section>): warning: common of `<symbol>'
                   overridden by larger common
                <file>(<section>): warning: larger common is here

    5.  Merging a common symbol with a previous smaller
        common symbol.  This is the same as the previous
        case, except that the symbols are encountered in a
        different order.












                            ‐38‐


                <file>(<section>): warning: common of `<symbol>'
                   overriding smaller common
                <file>(<section>): warning: smaller common is here

−−warn−constructors
    Warn if any global constructors are used.  This is only
    useful for a few object file formats.  For formats like
    COFF or ELF, the linker can not detect the use of global
    constructors.

−−warn−multiple−gp
    Warn if multiple global pointer values are required in
    the output file.  This is only meaningful for certain
    processors, such as the Alpha.  Specifically, some
    processors put large‐valued constants in a special
    section.  A special register (the global pointer) points
    into the middle of this section, so that constants can
    be loaded efficiently via a base‐register relative
    addressing mode.  Since the offset in base‐register
    relative mode is fixed and relatively small (e.g., 16
    bits), this limits the maximum size of the constant
    pool.  Thus, in large programs, it is often necessary to
    use multiple global pointer values in order to be able
    to address all possible constants.  This option causes a
    warning to be issued whenever this case occurs.

−−warn−once
    Only warn once for each undefined symbol, rather than
    once per module which refers to it.

−−warn−section−align
    Warn if the address of an output section is changed
    because of alignment.  Typically, the alignment will be
    set by an input section.  The address will only be
    changed if it not explicitly specified; that is, if the
    "SECTIONS" command does not specify a start address for
    the section.

−−warn−shared−textrel
    Warn if the linker adds a DT_TEXTREL to a shared object.

−−warn−alternate−em
    Warn if an object has alternate ELF machine code.

−−warn−unresolved−symbols
    If the linker is going to report an unresolved symbol
    (see the option −−unresolved−symbols) it will normally
    generate an error.  This option makes it generate a
    warning instead.

−−error−unresolved−symbols
    This restores the linker’s default behaviour of
    generating errors when it is reporting unresolved
    symbols.









                            ‐39‐


−−whole−archive
    For each archive mentioned on the command line after the
    −−whole−archive option, include every object file in the
    archive in the link, rather than searching the archive
    for the required object files.  This is normally used to
    turn an archive file into a shared library, forcing
    every object to be included in the resulting shared
    library.  This option may be used more than once.

    Two notes when using this option from gcc: First, gcc
    doesn’t know about this option, so you have to use
    −Wl,−whole−archive.  Second, don’t forget to use
    −Wl,−no−whole−archive after your list of archives,
    because gcc will add its own list of archives to your
    link and you may not want this flag to affect those as
    well.

−−wrap=symbol
    Use a wrapper function for symbol.  Any undefined
    reference to symbol will be resolved to "__wrap_symbol".
    Any undefined reference to "__real_symbol" will be
    resolved to symbol.

    This can be used to provide a wrapper for a system
    function.  The wrapper function should be called
    "__wrap_symbol".  If it wishes to call the system
    function, it should call "__real_symbol".

    Here is a trivial example:

            void *
            __wrap_malloc (size_t c)
            {
              printf ("malloc called with %zu\n", c);
              return __real_malloc (c);
            }

    If you link other code with this file using −−wrap
    malloc, then all calls to "malloc" will call the
    function "__wrap_malloc" instead.  The call to
    "__real_malloc" in "__wrap_malloc" will call the real
    "malloc" function.

    You may wish to provide a "__real_malloc" function as
    well, so that links without the −−wrap option will
    succeed.  If you do this, you should not put the
    definition of "__real_malloc" in the same file as
    "__wrap_malloc"; if you do, the assembler may resolve
    the call before the linker has a chance to wrap it to
    "malloc".

    Only undefined references are replaced by the linker.
    So, translation unit internal references to symbol are
    not resolved to "__wrap_symbol".  In the next example,









                            ‐40‐


    the call to "f" in "g" is not resolved to "__wrap_f".

            int
            f (void)
            {
              return 123;
            }

            int
            g (void)
            {
              return f();
            }

−−eh−frame−hdr

−−no−eh−frame−hdr
    Request (−−eh−frame−hdr) or suppress (−−no−eh−frame−hdr)
    the creation of ".eh_frame_hdr" section and ELF
    "PT_GNU_EH_FRAME" segment header.

−−no−ld−generated−unwind−info
    Request creation of ".eh_frame" unwind info for linker
    generated code sections like PLT.  This option is on by
    default if linker generated unwind info is supported.

−−enable−new−dtags

−−disable−new−dtags
    This linker can create the new dynamic tags in ELF. But
    the older ELF systems may not understand them. If you
    specify −−enable−new−dtags, the new dynamic tags will be
    created as needed and older dynamic tags will be
    omitted.  If you specify −−disable−new−dtags, no new
    dynamic tags will be created. By default, the new
    dynamic tags are not created. Note that those options
    are only available for ELF systems.

−−hash−size=number
    Set the default size of the linker’s hash tables to a
    prime number close to number.  Increasing this value can
    reduce the length of time it takes the linker to perform
    its tasks, at the expense of increasing the linker’s
    memory requirements.  Similarly reducing this value can
    reduce the memory requirements at the expense of speed.

−−hash−style=style
    Set the type of linker’s hash table(s).  style can be
    either "sysv" for classic ELF ".hash" section, "gnu" for
    new style GNU ".gnu.hash" section or "both" for both the
    classic ELF ".hash" and new style GNU ".gnu.hash" hash
    tables.  The default depends upon how the linker was
    configured, but for most Linux based systems it will be
    "both".









                            ‐41‐


−−compress−debug−sections=none

−−compress−debug−sections=zlib

−−compress−debug−sections=zlib−gnu

−−compress−debug−sections=zlib−gabi
    On ELF platforms, these options control how DWARF debug
    sections are compressed using zlib.

    −−compress−debug−sections=none doesn’t compress DWARF
    debug sections.  −−compress−debug−sections=zlib−gnu
    compresses DWARF debug sections and renames them to
    begin with .zdebug instead of .debug.
    −−compress−debug−sections=zlib−gabi also compresses
    DWARF debug sections, but rather than renaming them it
    sets the SHF_COMPRESSED flag in the sections’ headers.

    The −−compress−debug−sections=zlib option is an alias
    for −−compress−debug−sections=zlib−gabi.

    Note that this option overrides any compression in input
    debug sections, so if a binary is linked with
    −−compress−debug−sections=none for example, then any
    compressed debug sections in input files will be
    uncompressed before they are copied into the output
    binary.

    The default compression behaviour varies depending upon
    the target involved and the configure options used to
    build the toolchain.  The default can be determined by
    examining the output from the linker’s −−help option.

−−reduce−memory−overheads
    This option reduces memory requirements at ld runtime,
    at the expense of linking speed.  This was introduced to
    select the old O(n^2) algorithm for link map file
    generation, rather than the new O(n) algorithm which
    uses about 40% more memory for symbol storage.

    Another effect of the switch is to set the default hash
    table size to 1021, which again saves memory at the cost
    of lengthening the linker’s run time.  This is not done
    however if the −−hash−size switch has been used.

    The −−reduce−memory−overheads switch may be also be used
    to enable other tradeoffs in future versions of the
    linker.

−−build−id

−−build−id=style
    Request the creation of a ".note.gnu.build−id" ELF note
    section or a ".buildid" COFF section.  The contents of









                            ‐42‐


    the note are unique bits identifying this linked file.
    style can be "uuid" to use 128 random bits, "sha1" to
    use a 160−bit SHA1 hash on the normative parts of the
    output contents, "md5" to use a 128−bit MD5 hash on the
    normative parts of the output contents, or "0xhexstring"
    to use a chosen bit string specified as an even number
    of hexadecimal digits ("−" and ":" characters between
    digit pairs are ignored).  If style is omitted, "sha1"
    is used.

    The "md5" and "sha1" styles produces an identifier that
    is always the same in an identical output file, but will
    be unique among all nonidentical output files.  It is
    not intended to be compared as a checksum for the file’s
    contents.  A linked file may be changed later by other
    tools, but the build ID bit string identifying the
    original linked file does not change.

    Passing "none" for style disables the setting from any
    "−−build−id" options earlier on the command line.

     The i386 PE linker supports the −shared option, which
causes the output to be a dynamically linked library (DLL)
instead of a normal executable.  You should name the output
"*.dll" when you use this option.  In addition, the linker
fully supports the standard "*.def" files, which may be
specified on the linker command line like an object file (in
fact, it should precede archives it exports symbols from, to
ensure that they get linked in, just like a normal object
file).

     In addition to the options common to all targets, the
i386 PE linker support additional command‐line options that
are specific to the i386 PE target.  Options that take
values may be separated from their values by either a space
or an equals sign.

−−add−stdcall−alias
    If given, symbols with a stdcall suffix (@nn) will be
    exported as‐is and also with the suffix stripped.  [This
    option is specific to the i386 PE targeted port of the
    linker]

−−base−file file
    Use file as the name of a file in which to save the base
    addresses of all the relocations needed for generating
    DLLs with dlltool.  [This is an i386 PE specific option]

−−dll
    Create a DLL instead of a regular executable.  You may
    also use −shared or specify a "LIBRARY" in a given
    ".def" file.  [This option is specific to the i386 PE
    targeted port of the linker]










                            ‐43‐


−−enable−long−section−names

−−disable−long−section−names
    The PE variants of the COFF object format add an
    extension that permits the use of section names longer
    than eight characters, the normal limit for COFF.  By
    default, these names are only allowed in object files,
    as fully‐linked executable images do not carry the COFF
    string table required to support the longer names.  As a
    GNU extension, it is possible to allow their use in
    executable images as well, or to (probably pointlessly!)
    disallow it in object files, by using these two options.
    Executable images generated with these long section
    names are slightly non‐standard, carrying as they do a
    string table, and may generate confusing output when
    examined with non‐GNU PE‐aware tools, such as file
    viewers and dumpers.  However, GDB relies on the use of
    PE long section names to find Dwarf−2 debug information
    sections in an executable image at runtime, and so if
    neither option is specified on the command‐line, ld will
    enable long section names, overriding the default and
    technically correct behaviour, when it finds the
    presence of debug information while linking an
    executable image and not stripping symbols.  [This
    option is valid for all PE targeted ports of the linker]

−−enable−stdcall−fixup

−−disable−stdcall−fixup
    If the link finds a symbol that it cannot resolve, it
    will attempt to do "fuzzy linking" by looking for
    another defined symbol that differs only in the format
    of the symbol name (cdecl vs stdcall) and will resolve
    that symbol by linking to the match.  For example, the
    undefined symbol "_foo" might be linked to the function
    "_foo@12", or the undefined symbol "_bar@16" might be
    linked to the function "_bar".  When the linker does
    this, it prints a warning, since it normally should have
    failed to link, but sometimes import libraries generated
    from third‐party dlls may need this feature to be
    usable.  If you specify −−enable−stdcall−fixup, this
    feature is fully enabled and warnings are not printed.
    If you specify −−disable−stdcall−fixup, this feature is
    disabled and such mismatches are considered to be
    errors.  [This option is specific to the i386 PE
    targeted port of the linker]

−−leading−underscore

−−no−leading−underscore
    For most targets default symbol‐prefix is an underscore
    and is defined in target’s description. By this option
    it is possible to disable/enable the default underscore
    symbol‐prefix.









                            ‐44‐


−−export−all−symbols
    If given, all global symbols in the objects used to
    build a DLL will be exported by the DLL.  Note that this
    is the default if there otherwise wouldn’t be any
    exported symbols.  When symbols are explicitly exported
    via DEF files or implicitly exported via function
    attributes, the default is to not export anything else
    unless this option is given.  Note that the symbols
    "DllMain@12", "DllEntryPoint@0", "DllMainCRTStartup@12",
    and "impure_ptr" will not be automatically exported.
    Also, symbols imported from other DLLs will not be re‐
    exported, nor will symbols specifying the DLL’s internal
    layout such as those beginning with "_head_" or ending
    with "_iname".  In addition, no symbols from "libgcc",
    "libstd++", "libmingw32", or "crtX.o" will be exported.
    Symbols whose names begin with "__rtti_" or "__builtin_"
    will not be exported, to help with C++ DLLs.  Finally,
    there is an extensive list of cygwin‐private symbols
    that are not exported (obviously, this applies on when
    building DLLs for cygwin targets).  These cygwin‐
    excludes are: "_cygwin_dll_entry@12",
    "_cygwin_crt0_common@8",
    "_cygwin_noncygwin_dll_entry@12", "_fmode",
    "_impure_ptr", "cygwin_attach_dll", "cygwin_premain0",
    "cygwin_premain1", "cygwin_premain2", "cygwin_premain3",
    and "environ".  [This option is specific to the i386 PE
    targeted port of the linker]

−−exclude−symbols symbol,symbol,...
    Specifies a list of symbols which should not be
    automatically exported.  The symbol names may be
    delimited by commas or colons.  [This option is specific
    to the i386 PE targeted port of the linker]

−−exclude−all−symbols
    Specifies no symbols should be automatically exported.
    [This option is specific to the i386 PE targeted port of
    the linker]

−−file−alignment
    Specify the file alignment.  Sections in the file will
    always begin at file offsets which are multiples of this
    number.  This defaults to 512.  [This option is specific
    to the i386 PE targeted port of the linker]

−−heap reserve

−−heap reserve,commit
    Specify the number of bytes of memory to reserve (and
    optionally commit) to be used as heap for this program.
    The default is 1MB reserved, 4K committed.  [This option
    is specific to the i386 PE targeted port of the linker]











                            ‐45‐


−−image−base value
    Use value as the base address of your program or dll.
    This is the lowest memory location that will be used
    when your program or dll is loaded.  To reduce the need
    to relocate and improve performance of your dlls, each
    should have a unique base address and not overlap any
    other dlls.  The default is 0x400000 for executables,
    and 0x10000000 for dlls.  [This option is specific to
    the i386 PE targeted port of the linker]

−−kill−at
    If given, the stdcall suffixes (@nn) will be stripped
    from symbols before they are exported.  [This option is
    specific to the i386 PE targeted port of the linker]

−−large−address−aware
    If given, the appropriate bit in the "Characteristics"
    field of the COFF header is set to indicate that this
    executable supports virtual addresses greater than 2
    gigabytes.  This should be used in conjunction with the
    /3GB or /USERVA=value megabytes switch in the
    "[operating systems]" section of the BOOT.INI.
    Otherwise, this bit has no effect.  [This option is
    specific to PE targeted ports of the linker]

−−disable−large−address−aware
    Reverts the effect of a previous −−large−address−aware
    option.  This is useful if −−large−address−aware is
    always set by the compiler driver (e.g. Cygwin gcc) and
    the executable does not support virtual addresses
    greater than 2 gigabytes.  [This option is specific to
    PE targeted ports of the linker]

−−major−image−version value
    Sets the major number of the "image version".  Defaults
    to 1.  [This option is specific to the i386 PE targeted
    port of the linker]

−−major−os−version value
    Sets the major number of the "os version".  Defaults to
    4.  [This option is specific to the i386 PE targeted
    port of the linker]

−−major−subsystem−version value
    Sets the major number of the "subsystem version".
    Defaults to 4.  [This option is specific to the i386 PE
    targeted port of the linker]

−−minor−image−version value
    Sets the minor number of the "image version".  Defaults
    to 0.  [This option is specific to the i386 PE targeted
    port of the linker]











                            ‐46‐


−−minor−os−version value
    Sets the minor number of the "os version".  Defaults to
    0.  [This option is specific to the i386 PE targeted
    port of the linker]

−−minor−subsystem−version value
    Sets the minor number of the "subsystem version".
    Defaults to 0.  [This option is specific to the i386 PE
    targeted port of the linker]

−−output−def file
    The linker will create the file file which will contain
    a DEF file corresponding to the DLL the linker is
    generating.  This DEF file (which should be called
    "*.def") may be used to create an import library with
    "dlltool" or may be used as a reference to automatically
    or implicitly exported symbols.  [This option is
    specific to the i386 PE targeted port of the linker]

−−enable−auto−image−base

−−enable−auto−image−base=value
    Automatically choose the image base for DLLs, optionally
    starting with base value, unless one is specified using
    the "−−image−base" argument.  By using a hash generated
    from the dllname to create unique image bases for each
    DLL, in‐memory collisions and relocations which can
    delay program execution are avoided.  [This option is
    specific to the i386 PE targeted port of the linker]

−−disable−auto−image−base
    Do not automatically generate a unique image base.  If
    there is no user‐specified image base ("−−image−base")
    then use the platform default.  [This option is specific
    to the i386 PE targeted port of the linker]

−−dll−search−prefix string
    When linking dynamically to a dll without an import
    library, search for "<string><basename>.dll" in
    preference to "lib<basename>.dll". This behaviour allows
    easy distinction between DLLs built for the various
    "subplatforms": native, cygwin, uwin, pw, etc.  For
    instance, cygwin DLLs typically use
    "−−dll−search−prefix=cyg".  [This option is specific to
    the i386 PE targeted port of the linker]

−−enable−auto−import
    Do sophisticated linking of "_symbol" to "__imp__symbol"
    for DATA imports from DLLs, thus making it possible to
    bypass the dllimport mechanism on the user side and to
    reference unmangled symbol names.  [This option is
    specific to the i386 PE targeted port of the linker]

    The following remarks pertain to the original









                            ‐47‐


    implementation of the feature and are obsolete nowadays
    for Cygwin and MinGW targets.

    Note: Use of the ’auto−import’ extension will cause the
    text section of the image file to be made writable. This
    does not conform to the PE‐COFF format specification
    published by Microsoft.

    Note − use of the ’auto−import’ extension will also
    cause read only data which would normally be placed into
    the .rdata section to be placed into the .data section
    instead.  This is in order to work around a problem with
    consts that is described here:
    http://www.cygwin.com/ml/cygwin/2004−09/msg01101.html

    Using ’auto−import’ generally will ’just work’ ‐‐ but
    sometimes you may see this message:

    "variable ’<var>’ can’t be auto‐imported. Please read
    the documentation for ld’s "−−enable−auto−import" for
    details."

    This message occurs when some (sub)expression accesses
    an address ultimately given by the sum of two constants
    (Win32 import tables only allow one).  Instances where
    this may occur include accesses to member fields of
    struct variables imported from a DLL, as well as using a
    constant index into an array variable imported from a
    DLL.  Any multiword variable (arrays, structs, long
    long, etc) may trigger this error condition.  However,
    regardless of the exact data type of the offending
    exported variable, ld will always detect it, issue the
    warning, and exit.

    There are several ways to address this difficulty,
    regardless of the data type of the exported variable:

    One way is to use −−enable−runtime−pseudo−reloc switch.
    This leaves the task of adjusting references in your
    client code for runtime environment, so this method
    works only when runtime environment supports this
    feature.

    A second solution is to force one of the ’constants’ to
    be a variable ‐‐ that is, unknown and un‐optimizable at
    compile time.  For arrays, there are two possibilities:
    a) make the indexee (the array’s address) a variable, or
    b) make the ’constant’ index a variable.  Thus:

            extern type extern_array[];
            extern_array[1] −−>
               { volatile type *t=extern_array; t[1] }

    or









                            ‐48‐


            extern type extern_array[];
            extern_array[1] −−>
               { volatile int t=1; extern_array[t] }

    For structs (and most other multiword data types) the
    only option is to make the struct itself (or the long
    long, or the ...) variable:

            extern struct s extern_struct;
            extern_struct.field −−>
               { volatile struct s *t=&extern_struct; t−>field }

    or

            extern long long extern_ll;
            extern_ll −−>
              { volatile long long * local_ll=&extern_ll; *local_ll }

    A third method of dealing with this difficulty is to
    abandon ’auto−import’ for the offending symbol and mark
    it with "__declspec(dllimport)".  However, in practice
    that requires using compile‐time #defines to indicate
    whether you are building a DLL, building client code
    that will link to the DLL, or merely building/linking to
    a static library.   In making the choice between the
    various methods of resolving the ’direct address with
    constant offset’ problem, you should consider typical
    real‐world usage:

    Original:

            −−foo.h
            extern int arr[];
            −−foo.c
            #include "foo.h"
            void main(int argc, char **argv){
              printf("%d\n",arr[1]);
            }

    Solution 1:

            −−foo.h
            extern int arr[];
            −−foo.c
            #include "foo.h"
            void main(int argc, char **argv){
              /* This workaround is for win32 and cygwin; do not "optimize" */
              volatile int *parr = arr;
              printf("%d\n",parr[1]);
            }

    Solution 2:











                            ‐49‐


            −−foo.h
            /* Note: auto−export is assumed (no __declspec(dllexport)) */
            #if (defined(_WIN32) || defined(__CYGWIN__)) && \
              !(defined(FOO_BUILD_DLL) || defined(FOO_STATIC))
            #define FOO_IMPORT __declspec(dllimport)
            #else
            #define FOO_IMPORT
            #endif
            extern FOO_IMPORT int arr[];
            −−foo.c
            #include "foo.h"
            void main(int argc, char **argv){
              printf("%d\n",arr[1]);
            }

    A fourth way to avoid this problem is to re‐code your
    library to use a functional interface rather than a data
    interface for the offending variables (e.g. set_foo()
    and get_foo() accessor functions).

−−disable−auto−import
    Do not attempt to do sophisticated linking of "_symbol"
    to "__imp__symbol" for DATA imports from DLLs.  [This
    option is specific to the i386 PE targeted port of the
    linker]

−−enable−runtime−pseudo−reloc
    If your code contains expressions described in
    −−enable−auto−import section, that is, DATA imports from
    DLL with non‐zero offset, this switch will create a
    vector of ’runtime pseudo relocations’ which can be used
    by runtime environment to adjust references to such data
    in your client code.  [This option is specific to the
    i386 PE targeted port of the linker]

−−disable−runtime−pseudo−reloc
    Do not create pseudo relocations for non‐zero offset
    DATA imports from DLLs.  [This option is specific to the
    i386 PE targeted port of the linker]

−−enable−extra−pe−debug
    Show additional debug info related to auto‐import symbol
    thunking.  [This option is specific to the i386 PE
    targeted port of the linker]

−−section−alignment
    Sets the section alignment.  Sections in memory will
    always begin at addresses which are a multiple of this
    number.  Defaults to 0x1000.  [This option is specific
    to the i386 PE targeted port of the linker]

−−stack reserve











                            ‐50‐


−−stack reserve,commit
    Specify the number of bytes of memory to reserve (and
    optionally commit) to be used as stack for this program.
    The default is 2MB reserved, 4K committed.  [This option
    is specific to the i386 PE targeted port of the linker]

−−subsystem which

−−subsystem which:major

−−subsystem which:major.minor
    Specifies the subsystem under which your program will
    execute.  The legal values for which are "native",
    "windows", "console", "posix", and "xbox".  You may
    optionally set the subsystem version also.  Numeric
    values are also accepted for which.  [This option is
    specific to the i386 PE targeted port of the linker]

    The following options set flags in the
    "DllCharacteristics" field of the PE file header: [These
    options are specific to PE targeted ports of the linker]

−−high−entropy−va
    Image is compatible with 64−bit address space layout
    randomization (ASLR).

−−dynamicbase
    The image base address may be relocated using address
    space layout randomization (ASLR).  This feature was
    introduced with MS Windows Vista for i386 PE targets.

−−forceinteg
    Code integrity checks are enforced.

−−nxcompat
    The image is compatible with the Data Execution
    Prevention.  This feature was introduced with MS Windows
    XP SP2 for i386 PE targets.

−−no−isolation
    Although the image understands isolation, do not isolate
    the image.

−−no−seh
    The image does not use SEH. No SE handler may be called
    from this image.

−−no−bind
    Do not bind this image.

−−wdmdriver
    The driver uses the MS Windows Driver Model.











                            ‐51‐


−−tsaware
    The image is Terminal Server aware.

−−insert−timestamp

−−no−insert−timestamp
    Insert a real timestamp into the image.  This is the
    default behaviour as it matches legacy code and it means
    that the image will work with other, proprietary tools.
    The problem with this default is that it will result in
    slightly different images being produced each time the
    same sources are linked.  The option
    −−no−insert−timestamp can be used to insert a zero value
    for the timestamp, this ensuring that binaries produced
    from identical sources will compare identically.

     The C6X uClinux target uses a binary format called DSBT
to support shared libraries.  Each shared library in the
system needs to have a unique index; all executables use an
index of 0.

−−dsbt−size size
    This option sets the number of entries in the DSBT of
    the current executable or shared library to size.  The
    default is to create a table with 64 entries.

−−dsbt−index index
    This option sets the DSBT index of the current
    executable or shared library to index.  The default is
    0, which is appropriate for generating executables.  If
    a shared library is generated with a DSBT index of 0,
    the "R_C6000_DSBT_INDEX" relocs are copied into the
    output file.

    The −−no−merge−exidx−entries switch disables the merging
    of adjacent exidx entries in frame unwind info.

−−branch−stub
    This option enables linker branch relaxation by
    inserting branch stub sections when needed to extend the
    range of branches.  This option is usually not required
    since C−SKY supports branch and call instructions that
    can access the full memory range and branch relaxation
    is normally handled by the compiler or assembler.

−−stub−group−size=N
    This option allows finer control of linker branch stub
    creation.  It sets the maximum size of a group of input
    sections that can be handled by one stub section.  A
    negative value of N locates stub sections after their
    branches, while a positive value allows stub sections to
    appear either before or after the branches.  Values of 1
    or −1 indicate that the linker should choose suitable
    defaults.









                            ‐52‐


     The 68HC11 and 68HC12 linkers support specific options
to control the memory bank switching mapping and trampoline
code generation.

−−no−trampoline
    This option disables the generation of trampoline. By
    default a trampoline is generated for each far function
    which is called using a "jsr" instruction (this happens
    when a pointer to a far function is taken).

−−bank−window name
    This option indicates to the linker the name of the
    memory region in the MEMORY specification that describes
    the memory bank window.  The definition of such region
    is then used by the linker to compute paging and
    addresses within the memory window.

     The following options are supported to control handling
of GOT generation when linking for 68K targets.

−−got=type
    This option tells the linker which GOT generation scheme
    to use.  type should be one of single, negative,
    multigot or target.  For more information refer to the
    Info entry for ld.

     The following options are supported to control
microMIPS instruction generation and branch relocation
checks for ISA mode transitions when linking for MIPS
targets.

−−insn32

−−no−insn32
    These options control the choice of microMIPS
    instructions used in code generated by the linker, such
    as that in the PLT or lazy binding stubs, or in
    relaxation.  If −−insn32 is used, then the linker only
    uses 32−bit instruction encodings.  By default or if
    −−no−insn32 is used, all instruction encodings are used,
    including 16−bit ones where possible.

−−ignore−branch−isa

−−no−ignore−branch−isa
    These options control branch relocation checks for
    invalid ISA mode transitions.  If −−ignore−branch−isa is
    used, then the linker accepts any branch relocations and
    any ISA mode transition required is lost in relocation
    calculation, except for some cases of "BAL" instructions
    which meet relaxation conditions and are converted to
    equivalent "JALX" instructions as the associated
    relocation is calculated.  By default or if
    −−no−ignore−branch−isa is used a check is made causing









                            ‐53‐


    the loss of an ISA mode transition to produce an error.

You can change the behaviour of ld with the environment
variables "GNUTARGET", "LDEMULATION" and
"COLLECT_NO_DEMANGLE".

     "GNUTARGET" determines the input‐file object format if
you don’t use −b (or its synonym −−format).  Its value
should be one of the BFD names for an input format.  If
there is no "GNUTARGET" in the environment, ld uses the
natural format of the target. If "GNUTARGET" is set to
"default" then BFD attempts to discover the input format by
examining binary input files; this method often succeeds,
but there are potential ambiguities, since there is no
method of ensuring that the magic number used to specify
object‐file formats is unique.  However, the configuration
procedure for BFD on each system places the conventional
format for that system first in the search‐list, so
ambiguities are resolved in favor of convention.

     "LDEMULATION" determines the default emulation if you
don’t use the −m option.  The emulation can affect various
aspects of linker behaviour, particularly the default linker
script.  You can list the available emulations with the
−−verbose or −V options.  If the −m option is not used, and
the "LDEMULATION" environment variable is not defined, the
default emulation depends upon how the linker was
configured.

     Normally, the linker will default to demangling
symbols.  However, if "COLLECT_NO_DEMANGLE" is set in the
environment, then it will default to not demangling symbols.
This environment variable is used in a similar fashion by
the "gcc" linker wrapper program.  The default may be
overridden by the −−demangle and −−no−demangle options.

ar(1), nm(1), objcopy(1), objdump(1), readelf(1) and the
Info entries for binutils and ld.

Copyright (c) 1991−2019 Free Software Foundation, Inc.

     Permission is granted to copy, distribute and/or modify
this document under the terms of the GNU Free Documentation
License, Version 1.3 or any later version published by the
Free Software Foundation; with no Invariant Sections, with
no Front‐Cover Texts, and with no Back‐Cover Texts.  A copy
of the license is included in the section entitled "GNU Free
Documentation License".