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LD(1)                                           GNU Development Tools                                           LD(1)



NAME
       ld - The GNU linker

SYNOPSIS
       ld [options] objfile ...

DESCRIPTION
       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.

OPTIONS
       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.  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
       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.

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

       -A architecture
       --architecture=architecture
           In the current release of ld, this option is useful only for the Intel 960 family of architectures.  In
           that ld configuration, the architecture argument identifies the particular architecture in the 960 family,
           enabling some safeguards and modifying the archive-library search path.

           Future releases of ld may support similar functionality for other architecture families.

       -b input-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.

       --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
       --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

           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 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.

       -h name

       -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.

           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 "=", then the "=" 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

               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.

       -n
       --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.

       --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.

           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 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.

       -t
       --trace
           Print the names of the input files as ld processes them.

       -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.
           command.

       -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
           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.

       --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
       --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:

           combreloc
               Combines multiple reloc sections and sorts them to make dynamic symbol lookup caching possible.

           defs
               Disallows undefined symbols in object files.  Undefined symbols in shared libraries are still allowed.

           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.
               call resolution to the point when the function is called (lazy binding), rather than at load time.
               Lazy binding is the default.

           loadfltr
               Marks  the object that its filters be processed immediately at runtime.

           muldefs
               Allows multiple definitions.

           nocombreloc
               Disables multiple reloc sections combining.

           nocopyreloc
               Disables production of copy relocs.

           nodefaultlib
               Marks the object that the search for dependencies of this object will ignore any default library
               search paths.

           nodelete
               Marks the object shouldn't be unloaded at runtime.

           nodlopen
               Marks the object not available to "dlopen".

           nodump
               Marks the object can not be dumped by "dldump".

           noexecstack
               Marks the object as not requiring executable stack.

           norelro
               Don't create an ELF "PT_GNU_RELRO" segment header in the object.

           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 linked to using dlopen, instead of
               deferring function call resolution to the point when the function is first called.

           origin
               Marks the object may contain $ORIGIN.

           relro
               Create an ELF "PT_GNU_RELRO" segment header in the object.

           max-page-size=value
               Set the emulation maximum page size to value.

           common-page-size=value
               Set the emulation common page size to value.

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


           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.

           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
       -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

       -Bsymbolic-functions
           When creating a shared library, bind references to global function symbols to the definition within the
           shared library, if any.  This option is only meaningful on ELF platforms which support shared libraries.

       --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
           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.
           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.

       --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.

       --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.

           --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 and --undefined.

           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 an --entry or --undefined option or by a "ENTRY"

       --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.

       -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.

       --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,
               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.
           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.

       -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.

       -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.

           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

           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
           patch 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.

           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.

           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".

           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

       --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.

       --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.

       --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.

       --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
           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 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.

           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:

                       <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.

                       <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.
           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".

       --eh-frame-hdr
           Request 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 is "sysv".

       --reduce-memory-overheads
       --build-id=style
           Request the creation of a ".note.gnu.build-id" ELF note section or a ".build-id" COFF section.  The
           contents of 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]

       --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

           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.

       --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]

       --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
       --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]

       --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]

       --out-implib file
           The linker will create the file file which will contain an import lib corresponding to the DLL the linker
           is generating. This import lib (which should be called "*.dll.a" or "*.a" may be used to link clients
           against the generated DLL; this behaviour makes it possible to skip a separate "dlltool" import library
           creation step.  [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, and create the
           necessary thunking symbols when building the import libraries with those DATA exports. 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
           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

                   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
                   /* 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).  [This
           option is specific to the i386 PE targeted port of the linker]

       --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
       --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

       --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.

       --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 tiem 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 indentical 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 entires 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.

       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.

           32-bit instruction encodings.  By default or if --no-insn32 is used, all instruction encodings are used,
           including 16-bit ones where possible.

ENVIRONMENT
       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.

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

COPYRIGHT
       Copyright (c) 1991-2014 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".



binutils-2.25.1                                       2016-11-04                                                LD(1)