1LD(1)                        GNU Development Tools                       LD(1)
2
3
4

NAME

6       ld - The GNU linker
7

SYNOPSIS

9       ld [options] objfile ...
10

DESCRIPTION

12       ld combines a number of object and archive files, relocates their data
13       and ties up symbol references. Usually the last step in compiling a
14       program is to run ld.
15
16       ld accepts Linker Command Language files written in a superset of
17       AT&T's Link Editor Command Language syntax, to provide explicit and
18       total control over the linking process.
19
20       This man page does not describe the command language; see the ld entry
21       in "info" for full details on the command language and on other aspects
22       of the GNU linker.
23
24       This version of ld uses the general purpose BFD libraries to operate on
25       object files. This allows ld to read, combine, and write object files
26       in many different formats---for example, COFF or "a.out".  Different
27       formats may be linked together to produce any available kind of object
28       file.
29
30       Aside from its flexibility, the GNU linker is more helpful than other
31       linkers in providing diagnostic information.  Many linkers abandon
32       execution immediately upon encountering an error; whenever possible, ld
33       continues executing, allowing you to identify other errors (or, in some
34       cases, to get an output file in spite of the error).
35
36       The GNU linker ld is meant to cover a broad range of situations, and to
37       be as compatible as possible with other linkers.  As a result, you have
38       many choices to control its behavior.
39

OPTIONS

41       The linker supports a plethora of command-line options, but in actual
42       practice few of them are used in any particular context.  For instance,
43       a frequent use of ld is to link standard Unix object files on a
44       standard, supported Unix system.  On such a system, to link a file
45       "hello.o":
46
47               ld -o <output> /lib/crt0.o hello.o -lc
48
49       This tells ld to produce a file called output as the result of linking
50       the file "/lib/crt0.o" with "hello.o" and the library "libc.a", which
51       will come from the standard search directories.  (See the discussion of
52       the -l option below.)
53
54       Some of the command-line options to ld may be specified at any point in
55       the command line.  However, options which refer to files, such as -l or
56       -T, cause the file to be read at the point at which the option appears
57       in the command line, relative to the object files and other file
58       options.  Repeating non-file options with a different argument will
59       either have no further effect, or override prior occurrences (those
60       further to the left on the command line) of that option.  Options which
61       may be meaningfully specified more than once are noted in the
62       descriptions below.
63
64       Non-option arguments are object files or archives which are to be
65       linked together.  They may follow, precede, or be mixed in with
66       command-line options, except that an object file argument may not be
67       placed between an option and its argument.
68
69       Usually the linker is invoked with at least one object file, but you
70       can specify other forms of binary input files using -l, -R, and the
71       script command language.  If no binary input files at all are
72       specified, the linker does not produce any output, and issues the
73       message No input files.
74
75       If the linker cannot recognize the format of an object file, it will
76       assume that it is a linker script.  A script specified in this way
77       augments the main linker script used for the link (either the default
78       linker script or the one specified by using -T).  This feature permits
79       the linker to link against a file which appears to be an object or an
80       archive, but actually merely defines some symbol values, or uses
81       "INPUT" or "GROUP" to load other objects.  Specifying a script in this
82       way merely augments the main linker script, with the extra commands
83       placed after the main script; use the -T option to replace the default
84       linker script entirely, but note the effect of the "INSERT" command.
85
86       For options whose names are a single letter, option arguments must
87       either follow the option letter without intervening whitespace, or be
88       given as separate arguments immediately following the option that
89       requires them.
90
91       For options whose names are multiple letters, either one dash or two
92       can precede the option name; for example, -trace-symbol and
93       --trace-symbol are equivalent.  Note---there is one exception to this
94       rule.  Multiple letter options that start with a lower case 'o' can
95       only be preceded by two dashes.  This is to reduce confusion with the
96       -o option.  So for example -omagic sets the output file name to magic
97       whereas --omagic sets the NMAGIC flag on the output.
98
99       Arguments to multiple-letter options must either be separated from the
100       option name by an equals sign, or be given as separate arguments
101       immediately following the option that requires them.  For example,
102       --trace-symbol foo and --trace-symbol=foo are equivalent.  Unique
103       abbreviations of the names of multiple-letter options are accepted.
104
105       Note---if the linker is being invoked indirectly, via a compiler driver
106       (e.g. gcc) then all the linker command-line options should be prefixed
107       by -Wl, (or whatever is appropriate for the particular compiler driver)
108       like this:
109
110                 gcc -Wl,--start-group foo.o bar.o -Wl,--end-group
111
112       This is important, because otherwise the compiler driver program may
113       silently drop the linker options, resulting in a bad link.  Confusion
114       may also arise when passing options that require values through a
115       driver, as the use of a space between option and argument acts as a
116       separator, and causes the driver to pass only the option to the linker
117       and the argument to the compiler.  In this case, it is simplest to use
118       the joined forms of both single- and multiple-letter options, such as:
119
120                 gcc foo.o bar.o -Wl,-eENTRY -Wl,-Map=a.map
121
122       Here is a table of the generic command-line switches accepted by the
123       GNU linker:
124
125       @file
126           Read command-line options from file.  The options read are inserted
127           in place of the original @file option.  If file does not exist, or
128           cannot be read, then the option will be treated literally, and not
129           removed.
130
131           Options in file are separated by whitespace.  A whitespace
132           character may be included in an option by surrounding the entire
133           option in either single or double quotes.  Any character (including
134           a backslash) may be included by prefixing the character to be
135           included with a backslash.  The file may itself contain additional
136           @file options; any such options will be processed recursively.
137
138       -a keyword
139           This option is supported for HP/UX compatibility.  The keyword
140           argument must be one of the strings archive, shared, or default.
141           -aarchive is functionally equivalent to -Bstatic, and the other two
142           keywords are functionally equivalent to -Bdynamic.  This option may
143           be used any number of times.
144
145       --audit AUDITLIB
146           Adds AUDITLIB to the "DT_AUDIT" entry of the dynamic section.
147           AUDITLIB is not checked for existence, nor will it use the
148           DT_SONAME specified in the library.  If specified multiple times
149           "DT_AUDIT" will contain a colon separated list of audit interfaces
150           to use. If the linker finds an object with an audit entry while
151           searching for shared libraries, it will add a corresponding
152           "DT_DEPAUDIT" entry in the output file.  This option is only
153           meaningful on ELF platforms supporting the rtld-audit interface.
154
155       -b input-format
156       --format=input-format
157           ld may be configured to support more than one kind of object file.
158           If your ld is configured this way, you can use the -b option to
159           specify the binary format for input object files that follow this
160           option on the command line.  Even when ld is configured to support
161           alternative object formats, you don't usually need to specify this,
162           as ld should be configured to expect as a default input format the
163           most usual format on each machine.  input-format is a text string,
164           the name of a particular format supported by the BFD libraries.
165           (You can list the available binary formats with objdump -i.)
166
167           You may want to use this option if you are linking files with an
168           unusual binary format.  You can also use -b to switch formats
169           explicitly (when linking object files of different formats), by
170           including -b input-format before each group of object files in a
171           particular format.
172
173           The default format is taken from the environment variable
174           "GNUTARGET".
175
176           You can also define the input format from a script, using the
177           command "TARGET";
178
179       -c MRI-commandfile
180       --mri-script=MRI-commandfile
181           For compatibility with linkers produced by MRI, ld accepts script
182           files written in an alternate, restricted command language,
183           described in the MRI Compatible Script Files section of GNU ld
184           documentation.  Introduce MRI script files with the option -c; use
185           the -T option to run linker scripts written in the general-purpose
186           ld scripting language.  If MRI-cmdfile does not exist, ld looks for
187           it in the directories specified by any -L options.
188
189       -d
190       -dc
191       -dp These three options are equivalent; multiple forms are supported
192           for compatibility with other linkers.  They assign space to common
193           symbols even if a relocatable output file is specified (with -r).
194           The script command "FORCE_COMMON_ALLOCATION" has the same effect.
195
196       --depaudit AUDITLIB
197       -P AUDITLIB
198           Adds AUDITLIB to the "DT_DEPAUDIT" entry of the dynamic section.
199           AUDITLIB is not checked for existence, nor will it use the
200           DT_SONAME specified in the library.  If specified multiple times
201           "DT_DEPAUDIT" will contain a colon separated list of audit
202           interfaces to use.  This option is only meaningful on ELF platforms
203           supporting the rtld-audit interface.  The -P option is provided for
204           Solaris compatibility.
205
206       --enable-non-contiguous-regions
207           This option avoids generating an error if an input section does not
208           fit a matching output section. The linker tries to allocate the
209           input section to subseque nt matching output sections, and
210           generates an error only if no output section is large enough.  This
211           is useful when several non-contiguous memory regions are available
212           and the input section does not require a particular one.  The order
213           in which input sections are evaluated does not change, for
214           instance:
215
216                     MEMORY {
217                       MEM1 (rwx) : ORIGIN : 0x1000, LENGTH = 0x14
218                       MEM2 (rwx) : ORIGIN : 0x1000, LENGTH = 0x40
219                       MEM3 (rwx) : ORIGIN : 0x2000, LENGTH = 0x40
220                     }
221                     SECTIONS {
222                       mem1 : { *(.data.*); } > MEM1
223                       mem2 : { *(.data.*); } > MEM2
224                       mem3 : { *(.data.*); } > MEM2
225                     }
226
227                     with input sections:
228                     .data.1: size 8
229                     .data.2: size 0x10
230                     .data.3: size 4
231
232                     results in .data.1 affected to mem1, and .data.2 and .data.3
233                     affected to mem2, even though .data.3 would fit in mem3.
234
235           This option is incompatible with INSERT statements because it
236           changes the way input sections are mapped to output sections.
237
238       --enable-non-contiguous-regions-warnings
239           This option enables warnings when "--enable-non-contiguous-regions"
240           allows possibly unexpected matches in sections mapping, potentially
241           leading to silently discarding a section instead of failing because
242           it does not fit any output region.
243
244       -e entry
245       --entry=entry
246           Use entry as the explicit symbol for beginning execution of your
247           program, rather than the default entry point.  If there is no
248           symbol named entry, the linker will try to parse entry as a number,
249           and use that as the entry address (the number will be interpreted
250           in base 10; you may use a leading 0x for base 16, or a leading 0
251           for base 8).
252
253       --exclude-libs lib,lib,...
254           Specifies a list of archive libraries from which symbols should not
255           be automatically exported.  The library names may be delimited by
256           commas or colons.  Specifying "--exclude-libs ALL" excludes symbols
257           in all archive libraries from automatic export.  This option is
258           available only for the i386 PE targeted port of the linker and for
259           ELF targeted ports.  For i386 PE, symbols explicitly listed in a
260           .def file are still exported, regardless of this option.  For ELF
261           targeted ports, symbols affected by this option will be treated as
262           hidden.
263
264       --exclude-modules-for-implib module,module,...
265           Specifies a list of object files or archive members, from which
266           symbols should not be automatically exported, but which should be
267           copied wholesale into the import library being generated during the
268           link.  The module names may be delimited by commas or colons, and
269           must match exactly the filenames used by ld to open the files; for
270           archive members, this is simply the member name, but for object
271           files the name listed must include and match precisely any path
272           used to specify the input file on the linker's command-line.  This
273           option is available only for the i386 PE targeted port of the
274           linker.  Symbols explicitly listed in a .def file are still
275           exported, regardless of this option.
276
277       -E
278       --export-dynamic
279       --no-export-dynamic
280           When creating a dynamically linked executable, using the -E option
281           or the --export-dynamic option causes the linker to add all symbols
282           to the dynamic symbol table.  The dynamic symbol table is the set
283           of symbols which are visible from dynamic objects at run time.
284
285           If you do not use either of these options (or use the
286           --no-export-dynamic option to restore the default behavior), the
287           dynamic symbol table will normally contain only those symbols which
288           are referenced by some dynamic object mentioned in the link.
289
290           If you use "dlopen" to load a dynamic object which needs to refer
291           back to the symbols defined by the program, rather than some other
292           dynamic object, then you will probably need to use this option when
293           linking the program itself.
294
295           You can also use the dynamic list to control what symbols should be
296           added to the dynamic symbol table if the output format supports it.
297           See the description of --dynamic-list.
298
299           Note that this option is specific to ELF targeted ports.  PE
300           targets support a similar function to export all symbols from a DLL
301           or EXE; see the description of --export-all-symbols below.
302
303       --export-dynamic-symbol=glob
304           When creating a dynamically linked executable, symbols matching
305           glob will be added to the dynamic symbol table. When creating a
306           shared library, references to symbols matching glob will not be
307           bound to the definitions within the shared library. This option is
308           a no-op when creating a shared library and -Bsymbolic or
309           --dynamic-list are not specified. This option is only meaningful on
310           ELF platforms which support shared libraries.
311
312       --export-dynamic-symbol-list=file
313           Specify a --export-dynamic-symbol for each pattern in the file.
314           The format of the file is the same as the version node without
315           scope and node name.  See VERSION for more information.
316
317       -EB Link big-endian objects.  This affects the default output format.
318
319       -EL Link little-endian objects.  This affects the default output
320           format.
321
322       -f name
323       --auxiliary=name
324           When creating an ELF shared object, set the internal DT_AUXILIARY
325           field to the specified name.  This tells the dynamic linker that
326           the symbol table of the shared object should be used as an
327           auxiliary filter on the symbol table of the shared object name.
328
329           If you later link a program against this filter object, then, when
330           you run the program, the dynamic linker will see the DT_AUXILIARY
331           field.  If the dynamic linker resolves any symbols from the filter
332           object, it will first check whether there is a definition in the
333           shared object name.  If there is one, it will be used instead of
334           the definition in the filter object.  The shared object name need
335           not exist.  Thus the shared object name may be used to provide an
336           alternative implementation of certain functions, perhaps for
337           debugging or for machine-specific performance.
338
339           This option may be specified more than once.  The DT_AUXILIARY
340           entries will be created in the order in which they appear on the
341           command line.
342
343       -F name
344       --filter=name
345           When creating an ELF shared object, set the internal DT_FILTER
346           field to the specified name.  This tells the dynamic linker that
347           the symbol table of the shared object which is being created should
348           be used as a filter on the symbol table of the shared object name.
349
350           If you later link a program against this filter object, then, when
351           you run the program, the dynamic linker will see the DT_FILTER
352           field.  The dynamic linker will resolve symbols according to the
353           symbol table of the filter object as usual, but it will actually
354           link to the definitions found in the shared object name.  Thus the
355           filter object can be used to select a subset of the symbols
356           provided by the object name.
357
358           Some older linkers used the -F option throughout a compilation
359           toolchain for specifying object-file format for both input and
360           output object files.  The GNU linker uses other mechanisms for this
361           purpose: the -b, --format, --oformat options, the "TARGET" command
362           in linker scripts, and the "GNUTARGET" environment variable.  The
363           GNU linker will ignore the -F option when not creating an ELF
364           shared object.
365
366       -fini=name
367           When creating an ELF executable or shared object, call NAME when
368           the executable or shared object is unloaded, by setting DT_FINI to
369           the address of the function.  By default, the linker uses "_fini"
370           as the function to call.
371
372       -g  Ignored.  Provided for compatibility with other tools.
373
374       -G value
375       --gpsize=value
376           Set the maximum size of objects to be optimized using the GP
377           register to size.  This is only meaningful for object file formats
378           such as MIPS ELF that support putting large and small objects into
379           different sections.  This is ignored for other object file formats.
380
381       -h name
382       -soname=name
383           When creating an ELF shared object, set the internal DT_SONAME
384           field to the specified name.  When an executable is linked with a
385           shared object which has a DT_SONAME field, then when the executable
386           is run the dynamic linker will attempt to load the shared object
387           specified by the DT_SONAME field rather than using the file name
388           given to the linker.
389
390       -i  Perform an incremental link (same as option -r).
391
392       -init=name
393           When creating an ELF executable or shared object, call NAME when
394           the executable or shared object is loaded, by setting DT_INIT to
395           the address of the function.  By default, the linker uses "_init"
396           as the function to call.
397
398       -l namespec
399       --library=namespec
400           Add the archive or object file specified by namespec to the list of
401           files to link.  This option may be used any number of times.  If
402           namespec is of the form :filename, ld will search the library path
403           for a file called filename, otherwise it will search the library
404           path for a file called libnamespec.a.
405
406           On systems which support shared libraries, ld may also search for
407           files other than libnamespec.a.  Specifically, on ELF and SunOS
408           systems, ld will search a directory for a library called
409           libnamespec.so before searching for one called libnamespec.a.  (By
410           convention, a ".so" extension indicates a shared library.)  Note
411           that this behavior does not apply to :filename, which always
412           specifies a file called filename.
413
414           The linker will search an archive only once, at the location where
415           it is specified on the command line.  If the archive defines a
416           symbol which was undefined in some object which appeared before the
417           archive on the command line, the linker will include the
418           appropriate file(s) from the archive.  However, an undefined symbol
419           in an object appearing later on the command line will not cause the
420           linker to search the archive again.
421
422           See the -( option for a way to force the linker to search archives
423           multiple times.
424
425           You may list the same archive multiple times on the command line.
426
427           This type of archive searching is standard for Unix linkers.
428           However, if you are using ld on AIX, note that it is different from
429           the behaviour of the AIX linker.
430
431       -L searchdir
432       --library-path=searchdir
433           Add path searchdir to the list of paths that ld will search for
434           archive libraries and ld control scripts.  You may use this option
435           any number of times.  The directories are searched in the order in
436           which they are specified on the command line.  Directories
437           specified on the command line are searched before the default
438           directories.  All -L options apply to all -l options, regardless of
439           the order in which the options appear.  -L options do not affect
440           how ld searches for a linker script unless -T option is specified.
441
442           If searchdir begins with "=" or $SYSROOT, then this prefix will be
443           replaced by the sysroot prefix, controlled by the --sysroot option,
444           or specified when the linker is configured.
445
446           The default set of paths searched (without being specified with -L)
447           depends on which emulation mode ld is using, and in some cases also
448           on how it was configured.
449
450           The paths can also be specified in a link script with the
451           "SEARCH_DIR" command.  Directories specified this way are searched
452           at the point in which the linker script appears in the command
453           line.
454
455       -m emulation
456           Emulate the emulation linker.  You can list the available
457           emulations with the --verbose or -V options.
458
459           If the -m option is not used, the emulation is taken from the
460           "LDEMULATION" environment variable, if that is defined.
461
462           Otherwise, the default emulation depends upon how the linker was
463           configured.
464
465       -M
466       --print-map
467           Print a link map to the standard output.  A link map provides
468           information about the link, including the following:
469
470           •   Where object files are mapped into memory.
471
472           •   How common symbols are allocated.
473
474           •   All archive members included in the link, with a mention of the
475               symbol which caused the archive member to be brought in.
476
477           •   The values assigned to symbols.
478
479               Note - symbols whose values are computed by an expression which
480               involves a reference to a previous value of the same symbol may
481               not have correct result displayed in the link map.  This is
482               because the linker discards intermediate results and only
483               retains the final value of an expression.  Under such
484               circumstances the linker will display the final value enclosed
485               by square brackets.  Thus for example a linker script
486               containing:
487
488                          foo = 1
489                          foo = foo * 4
490                          foo = foo + 8
491
492               will produce the following output in the link map if the -M
493               option is used:
494
495                          0x00000001                foo = 0x1
496                          [0x0000000c]                foo = (foo * 0x4)
497                          [0x0000000c]                foo = (foo + 0x8)
498
499               See Expressions for more information about expressions in
500               linker scripts.
501
502           •   How GNU properties are merged.
503
504               When the linker merges input .note.gnu.property sections into
505               one output .note.gnu.property section, some properties are
506               removed or updated.  These actions are reported in the link
507               map.  For example:
508
509                       Removed property 0xc0000002 to merge foo.o (0x1) and bar.o (not found)
510
511               This indicates that property 0xc0000002 is removed from output
512               when merging properties in  foo.o, whose property 0xc0000002
513               value is 0x1, and bar.o, which doesn't have property
514               0xc0000002.
515
516                       Updated property 0xc0010001 (0x1) to merge foo.o (0x1) and bar.o (0x1)
517
518               This indicates that property 0xc0010001 value is updated to 0x1
519               in output when merging properties in  foo.o, whose 0xc0010001
520               property value is 0x1, and bar.o, whose 0xc0010001 property
521               value is 0x1.
522
523       --print-map-discarded
524       --no-print-map-discarded
525           Print (or do not print) the list of discarded and garbage collected
526           sections in the link map.  Enabled by default.
527
528       -n
529       --nmagic
530           Turn off page alignment of sections, and disable linking against
531           shared libraries.  If the output format supports Unix style magic
532           numbers, mark the output as "NMAGIC".
533
534       -N
535       --omagic
536           Set the text and data sections to be readable and writable.  Also,
537           do not page-align the data segment, and disable linking against
538           shared libraries.  If the output format supports Unix style magic
539           numbers, mark the output as "OMAGIC". Note: Although a writable
540           text section is allowed for PE-COFF targets, it does not conform to
541           the format specification published by Microsoft.
542
543       --no-omagic
544           This option negates most of the effects of the -N option.  It sets
545           the text section to be read-only, and forces the data segment to be
546           page-aligned.  Note - this option does not enable linking against
547           shared libraries.  Use -Bdynamic for this.
548
549       -o output
550       --output=output
551           Use output as the name for the program produced by ld; if this
552           option is not specified, the name a.out is used by default.  The
553           script command "OUTPUT" can also specify the output file name.
554
555       --dependency-file=depfile
556           Write a dependency file to depfile.  This file contains a rule
557           suitable for "make" describing the output file and all the input
558           files that were read to produce it.  The output is similar to the
559           compiler's output with -M -MP.  Note that there is no option like
560           the compiler's -MM, to exclude "system files" (which is not a well-
561           specified concept in the linker, unlike "system headers" in the
562           compiler).  So the output from --dependency-file is always specific
563           to the exact state of the installation where it was produced, and
564           should not be copied into distributed makefiles without careful
565           editing.
566
567       -O level
568           If level is a numeric values greater than zero ld optimizes the
569           output.  This might take significantly longer and therefore
570           probably should only be enabled for the final binary.  At the
571           moment this option only affects ELF shared library generation.
572           Future releases of the linker may make more use of this option.
573           Also currently there is no difference in the linker's behaviour for
574           different non-zero values of this option.  Again this may change
575           with future releases.
576
577       -plugin name
578           Involve a plugin in the linking process.  The name parameter is the
579           absolute filename of the plugin.  Usually this parameter is
580           automatically added by the complier, when using link time
581           optimization, but users can also add their own plugins if they so
582           wish.
583
584           Note that the location of the compiler originated plugins is
585           different from the place where the ar, nm and ranlib programs
586           search for their plugins.  In order for those commands to make use
587           of a compiler based plugin it must first be copied into the
588           ${libdir}/bfd-plugins directory.  All gcc based linker plugins are
589           backward compatible, so it is sufficient to just copy in the newest
590           one.
591
592       --push-state
593           The --push-state allows one to preserve the current state of the
594           flags which govern the input file handling so that they can all be
595           restored with one corresponding --pop-state option.
596
597           The option which are covered are: -Bdynamic, -Bstatic, -dn, -dy,
598           -call_shared, -non_shared, -static, -N, -n, --whole-archive,
599           --no-whole-archive, -r, -Ur, --copy-dt-needed-entries,
600           --no-copy-dt-needed-entries, --as-needed, --no-as-needed, and -a.
601
602           One target for this option are specifications for pkg-config.  When
603           used with the --libs option all possibly needed libraries are
604           listed and then possibly linked with all the time.  It is better to
605           return something as follows:
606
607                   -Wl,--push-state,--as-needed -libone -libtwo -Wl,--pop-state
608
609       --pop-state
610           Undoes the effect of --push-state, restores the previous values of
611           the flags governing input file handling.
612
613       -q
614       --emit-relocs
615           Leave relocation sections and contents in fully linked executables.
616           Post link analysis and optimization tools may need this information
617           in order to perform correct modifications of executables.  This
618           results in larger executables.
619
620           This option is currently only supported on ELF platforms.
621
622       --force-dynamic
623           Force the output file to have dynamic sections.  This option is
624           specific to VxWorks targets.
625
626       -r
627       --relocatable
628           Generate relocatable output---i.e., generate an output file that
629           can in turn serve as input to ld.  This is often called partial
630           linking.  As a side effect, in environments that support standard
631           Unix magic numbers, this option also sets the output file's magic
632           number to "OMAGIC".  If this option is not specified, an absolute
633           file is produced.  When linking C++ programs, this option will not
634           resolve references to constructors; to do that, use -Ur.
635
636           When an input file does not have the same format as the output
637           file, partial linking is only supported if that input file does not
638           contain any relocations.  Different output formats can have further
639           restrictions; for example some "a.out"-based formats do not support
640           partial linking with input files in other formats at all.
641
642           This option does the same thing as -i.
643
644       -R filename
645       --just-symbols=filename
646           Read symbol names and their addresses from filename, but do not
647           relocate it or include it in the output.  This allows your output
648           file to refer symbolically to absolute locations of memory defined
649           in other programs.  You may use this option more than once.
650
651           For compatibility with other ELF linkers, if the -R option is
652           followed by a directory name, rather than a file name, it is
653           treated as the -rpath option.
654
655       -s
656       --strip-all
657           Omit all symbol information from the output file.
658
659       -S
660       --strip-debug
661           Omit debugger symbol information (but not all symbols) from the
662           output file.
663
664       --strip-discarded
665       --no-strip-discarded
666           Omit (or do not omit) global symbols defined in discarded sections.
667           Enabled by default.
668
669       -t
670       --trace
671           Print the names of the input files as ld processes them.  If -t is
672           given twice then members within archives are also printed.  -t
673           output is useful to generate a list of all the object files and
674           scripts involved in linking, for example, when packaging files for
675           a linker bug report.
676
677       -T scriptfile
678       --script=scriptfile
679           Use scriptfile as the linker script.  This script replaces ld's
680           default linker script (rather than adding to it), so commandfile
681           must specify everything necessary to describe the output file.
682           If scriptfile does not exist in the current directory, "ld" looks
683           for it in the directories specified by any preceding -L options.
684           Multiple -T options accumulate.
685
686       -dT scriptfile
687       --default-script=scriptfile
688           Use scriptfile as the default linker script.
689
690           This option is similar to the --script option except that
691           processing of the script is delayed until after the rest of the
692           command line has been processed.  This allows options placed after
693           the --default-script option on the command line to affect the
694           behaviour of the linker script, which can be important when the
695           linker command line cannot be directly controlled by the user.  (eg
696           because the command line is being constructed by another tool, such
697           as gcc).
698
699       -u symbol
700       --undefined=symbol
701           Force symbol to be entered in the output file as an undefined
702           symbol.  Doing this may, for example, trigger linking of additional
703           modules from standard libraries.  -u may be repeated with different
704           option arguments to enter additional undefined symbols.  This
705           option is equivalent to the "EXTERN" linker script command.
706
707           If this option is being used to force additional modules to be
708           pulled into the link, and if it is an error for the symbol to
709           remain undefined, then the option --require-defined should be used
710           instead.
711
712       --require-defined=symbol
713           Require that symbol is defined in the output file.  This option is
714           the same as option --undefined except that if symbol is not defined
715           in the output file then the linker will issue an error and exit.
716           The same effect can be achieved in a linker script by using
717           "EXTERN", "ASSERT" and "DEFINED" together.  This option can be used
718           multiple times to require additional symbols.
719
720       -Ur For anything other than C++ programs, this option is equivalent to
721           -r: it generates relocatable output---i.e., an output file that can
722           in turn serve as input to ld.  When linking C++ programs, -Ur does
723           resolve references to constructors, unlike -r.  It does not work to
724           use -Ur on files that were themselves linked with -Ur; once the
725           constructor table has been built, it cannot be added to.  Use -Ur
726           only for the last partial link, and -r for the others.
727
728       --orphan-handling=MODE
729           Control how orphan sections are handled.  An orphan section is one
730           not specifically mentioned in a linker script.
731
732           MODE can have any of the following values:
733
734           "place"
735               Orphan sections are placed into a suitable output section
736               following the strategy described in Orphan Sections.  The
737               option --unique also affects how sections are placed.
738
739           "discard"
740               All orphan sections are discarded, by placing them in the
741               /DISCARD/ section.
742
743           "warn"
744               The linker will place the orphan section as for "place" and
745               also issue a warning.
746
747           "error"
748               The linker will exit with an error if any orphan section is
749               found.
750
751           The default if --orphan-handling is not given is "place".
752
753       --unique[=SECTION]
754           Creates a separate output section for every input section matching
755           SECTION, or if the optional wildcard SECTION argument is missing,
756           for every orphan input section.  An orphan section is one not
757           specifically mentioned in a linker script.  You may use this option
758           multiple times on the command line;  It prevents the normal merging
759           of input sections with the same name, overriding output section
760           assignments in a linker script.
761
762       -v
763       --version
764       -V  Display the version number for ld.  The -V option also lists the
765           supported emulations.
766
767       -x
768       --discard-all
769           Delete all local symbols.
770
771       -X
772       --discard-locals
773           Delete all temporary local symbols.  (These symbols start with
774           system-specific local label prefixes, typically .L for ELF systems
775           or L for traditional a.out systems.)
776
777       -y symbol
778       --trace-symbol=symbol
779           Print the name of each linked file in which symbol appears.  This
780           option may be given any number of times.  On many systems it is
781           necessary to prepend an underscore.
782
783           This option is useful when you have an undefined symbol in your
784           link but don't know where the reference is coming from.
785
786       -Y path
787           Add path to the default library search path.  This option exists
788           for Solaris compatibility.
789
790       -z keyword
791           The recognized keywords are:
792
793           bndplt
794               Always generate BND prefix in PLT entries. Supported for
795               Linux/x86_64.
796
797           call-nop=prefix-addr
798           call-nop=suffix-nop
799           call-nop=prefix-byte
800           call-nop=suffix-byte
801               Specify the 1-byte "NOP" padding when transforming indirect
802               call to a locally defined function, foo, via its GOT slot.
803               call-nop=prefix-addr generates "0x67 call foo".
804               call-nop=suffix-nop generates "call foo 0x90".
805               call-nop=prefix-byte generates "byte call foo".
806               call-nop=suffix-byte generates "call foo byte".  Supported for
807               i386 and x86_64.
808
809           cet-report=none
810           cet-report=warning
811           cet-report=error
812               Specify how to report the missing
813               GNU_PROPERTY_X86_FEATURE_1_IBT and
814               GNU_PROPERTY_X86_FEATURE_1_SHSTK properties in input
815               .note.gnu.property section.  cet-report=none, which is the
816               default, will make the linker not report missing properties in
817               input files.  cet-report=warning will make the linker issue a
818               warning for missing properties in input files.
819               cet-report=error will make the linker issue an error for
820               missing properties in input files.  Note that ibt will turn off
821               the missing GNU_PROPERTY_X86_FEATURE_1_IBT property report and
822               shstk will turn off the missing
823               GNU_PROPERTY_X86_FEATURE_1_SHSTK property report.  Supported
824               for Linux/i386 and Linux/x86_64.
825
826           combreloc
827           nocombreloc
828               Combine multiple dynamic relocation sections and sort to
829               improve dynamic symbol lookup caching.  Do not do this if
830               nocombreloc.
831
832           common
833           nocommon
834               Generate common symbols with STT_COMMON type during a
835               relocatable link.  Use STT_OBJECT type if nocommon.
836
837           common-page-size=value
838               Set the page size most commonly used to value.  Memory image
839               layout will be optimized to minimize memory pages if the system
840               is using pages of this size.
841
842           defs
843               Report unresolved symbol references from regular object files.
844               This is done even if the linker is creating a non-symbolic
845               shared library.  This option is the inverse of -z undefs.
846
847           dynamic-undefined-weak
848           nodynamic-undefined-weak
849               Make undefined weak symbols dynamic when building a dynamic
850               object, if they are referenced from a regular object file and
851               not forced local by symbol visibility or versioning.  Do not
852               make them dynamic if nodynamic-undefined-weak.  If neither
853               option is given, a target may default to either option being in
854               force, or make some other selection of undefined weak symbols
855               dynamic.  Not all targets support these options.
856
857           execstack
858               Marks the object as requiring executable stack.
859
860           global
861               This option is only meaningful when building a shared object.
862               It makes the symbols defined by this shared object available
863               for symbol resolution of subsequently loaded libraries.
864
865           globalaudit
866               This option is only meaningful when building a dynamic
867               executable.  This option marks the executable as requiring
868               global auditing by setting the "DF_1_GLOBAUDIT" bit in the
869               "DT_FLAGS_1" dynamic tag.  Global auditing requires that any
870               auditing library defined via the --depaudit or -P command-line
871               options be run for all dynamic objects loaded by the
872               application.
873
874           ibtplt
875               Generate Intel Indirect Branch Tracking (IBT) enabled PLT
876               entries.  Supported for Linux/i386 and Linux/x86_64.
877
878           ibt Generate GNU_PROPERTY_X86_FEATURE_1_IBT in .note.gnu.property
879               section to indicate compatibility with IBT.  This also implies
880               ibtplt.  Supported for Linux/i386 and Linux/x86_64.
881
882           indirect-extern-access
883           noindirect-extern-access
884               Generate GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS in
885               .note.gnu.property section to indicate that object file
886               requires canonical function pointers and cannot be used with
887               copy relocation.  This option also implies noextern-protected-
888               data and nocopyreloc.  Supported for i386 and x86-64.
889
890               noindirect-extern-access removes
891               GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS from
892               .note.gnu.property section.
893
894           initfirst
895               This option is only meaningful when building a shared object.
896               It marks the object so that its runtime initialization will
897               occur before the runtime initialization of any other objects
898               brought into the process at the same time.  Similarly the
899               runtime finalization of the object will occur after the runtime
900               finalization of any other objects.
901
902           interpose
903               Specify that the dynamic loader should modify its symbol search
904               order so that symbols in this shared library interpose all
905               other shared libraries not so marked.
906
907           unique
908           nounique
909               When generating a shared library or other dynamically loadable
910               ELF object mark it as one that should (by default) only ever be
911               loaded once, and only in the main namespace (when using
912               "dlmopen"). This is primarily used to mark fundamental
913               libraries such as libc, libpthread et al which do not usually
914               function correctly unless they are the sole instances of
915               themselves. This behaviour can be overridden by the "dlmopen"
916               caller and does not apply to certain loading mechanisms (such
917               as audit libraries).
918
919           lam-u48
920               Generate GNU_PROPERTY_X86_FEATURE_1_LAM_U48 in
921               .note.gnu.property section to indicate compatibility with Intel
922               LAM_U48.  Supported for Linux/x86_64.
923
924           lam-u57
925               Generate GNU_PROPERTY_X86_FEATURE_1_LAM_U57 in
926               .note.gnu.property section to indicate compatibility with Intel
927               LAM_U57.  Supported for Linux/x86_64.
928
929           lam-u48-report=none
930           lam-u48-report=warning
931           lam-u48-report=error
932               Specify how to report the missing
933               GNU_PROPERTY_X86_FEATURE_1_LAM_U48 property in input
934               .note.gnu.property section.  lam-u48-report=none, which is the
935               default, will make the linker not report missing properties in
936               input files.  lam-u48-report=warning will make the linker issue
937               a warning for missing properties in input files.
938               lam-u48-report=error will make the linker issue an error for
939               missing properties in input files.  Supported for Linux/x86_64.
940
941           lam-u57-report=none
942           lam-u57-report=warning
943           lam-u57-report=error
944               Specify how to report the missing
945               GNU_PROPERTY_X86_FEATURE_1_LAM_U57 property in input
946               .note.gnu.property section.  lam-u57-report=none, which is the
947               default, will make the linker not report missing properties in
948               input files.  lam-u57-report=warning will make the linker issue
949               a warning for missing properties in input files.
950               lam-u57-report=error will make the linker issue an error for
951               missing properties in input files.  Supported for Linux/x86_64.
952
953           lam-report=none
954           lam-report=warning
955           lam-report=error
956               Specify how to report the missing
957               GNU_PROPERTY_X86_FEATURE_1_LAM_U48 and
958               GNU_PROPERTY_X86_FEATURE_1_LAM_U57 properties in input
959               .note.gnu.property section.  lam-report=none, which is the
960               default, will make the linker not report missing properties in
961               input files.  lam-report=warning will make the linker issue a
962               warning for missing properties in input files.
963               lam-report=error will make the linker issue an error for
964               missing properties in input files.  Supported for Linux/x86_64.
965
966           lazy
967               When generating an executable or shared library, mark it to
968               tell the dynamic linker to defer function call resolution to
969               the point when the function is called (lazy binding), rather
970               than at load time.  Lazy binding is the default.
971
972           loadfltr
973               Specify that the object's filters be processed immediately at
974               runtime.
975
976           max-page-size=value
977               Set the maximum memory page size supported to value.
978
979           muldefs
980               Allow multiple definitions.
981
982           nocopyreloc
983               Disable linker generated .dynbss variables used in place of
984               variables defined in shared libraries.  May result in dynamic
985               text relocations.
986
987           nodefaultlib
988               Specify that the dynamic loader search for dependencies of this
989               object should ignore any default library search paths.
990
991           nodelete
992               Specify that the object shouldn't be unloaded at runtime.
993
994           nodlopen
995               Specify that the object is not available to "dlopen".
996
997           nodump
998               Specify that the object can not be dumped by "dldump".
999
1000           noexecstack
1001               Marks the object as not requiring executable stack.
1002
1003           noextern-protected-data
1004               Don't treat protected data symbols as external when building a
1005               shared library.  This option overrides the linker backend
1006               default.  It can be used to work around incorrect relocations
1007               against protected data symbols generated by compiler.  Updates
1008               on protected data symbols by another module aren't visible to
1009               the resulting shared library.  Supported for i386 and x86-64.
1010
1011           noreloc-overflow
1012               Disable relocation overflow check.  This can be used to disable
1013               relocation overflow check if there will be no dynamic
1014               relocation overflow at run-time.  Supported for x86_64.
1015
1016           now When generating an executable or shared library, mark it to
1017               tell the dynamic linker to resolve all symbols when the program
1018               is started, or when the shared library is loaded by dlopen,
1019               instead of deferring function call resolution to the point when
1020               the function is first called.
1021
1022           origin
1023               Specify that the object requires $ORIGIN handling in paths.
1024
1025           pack-relative-relocs
1026           nopack-relative-relocs
1027               Generate compact relative relocation in position-independent
1028               executable and shared library.  It adds "DT_RELR", "DT_RELRSZ"
1029               and "DT_RELRENT" entries to the dynamic section.  It is ignored
1030               when building position-dependent executable and relocatable
1031               output.  nopack-relative-relocs is the default, which disables
1032               compact relative relocation.  When linked against the GNU C
1033               Library, a GLIBC_ABI_DT_RELR symbol version dependency on the
1034               shared C Library is added to the output.  Supported for i386
1035               and x86-64.
1036
1037           relro
1038           norelro
1039               Create an ELF "PT_GNU_RELRO" segment header in the object.
1040               This specifies a memory segment that should be made read-only
1041               after relocation, if supported.  Specifying common-page-size
1042               smaller than the system page size will render this protection
1043               ineffective.  Don't create an ELF "PT_GNU_RELRO" segment if
1044               norelro.
1045
1046           report-relative-reloc
1047               Report dynamic relative relocations generated by linker.
1048               Supported for Linux/i386 and Linux/x86_64.
1049
1050           separate-code
1051           noseparate-code
1052               Create separate code "PT_LOAD" segment header in the object.
1053               This specifies a memory segment that should contain only
1054               instructions and must be in wholly disjoint pages from any
1055               other data.  Don't create separate code "PT_LOAD" segment if
1056               noseparate-code is used.
1057
1058           shstk
1059               Generate GNU_PROPERTY_X86_FEATURE_1_SHSTK in .note.gnu.property
1060               section to indicate compatibility with Intel Shadow Stack.
1061               Supported for Linux/i386 and Linux/x86_64.
1062
1063           stack-size=value
1064               Specify a stack size for an ELF "PT_GNU_STACK" segment.
1065               Specifying zero will override any default non-zero sized
1066               "PT_GNU_STACK" segment creation.
1067
1068           start-stop-gc
1069           nostart-stop-gc
1070               When --gc-sections is in effect, a reference from a retained
1071               section to "__start_SECNAME" or "__stop_SECNAME" causes all
1072               input sections named "SECNAME" to also be retained, if
1073               "SECNAME" is representable as a C identifier and either
1074               "__start_SECNAME" or "__stop_SECNAME" is synthesized by the
1075               linker.  -z start-stop-gc disables this effect, allowing
1076               sections to be garbage collected as if the special synthesized
1077               symbols were not defined.  -z start-stop-gc has no effect on a
1078               definition of "__start_SECNAME" or "__stop_SECNAME" in an
1079               object file or linker script.  Such a definition will prevent
1080               the linker providing a synthesized "__start_SECNAME" or
1081               "__stop_SECNAME" respectively, and therefore the special
1082               treatment by garbage collection for those references.
1083
1084           start-stop-visibility=value
1085               Specify the ELF symbol visibility for synthesized
1086               "__start_SECNAME" and "__stop_SECNAME" symbols.  value must be
1087               exactly default, internal, hidden, or protected.  If no -z
1088               start-stop-visibility option is given, protected is used for
1089               compatibility with historical practice.  However, it's highly
1090               recommended to use -z start-stop-visibility=hidden in new
1091               programs and shared libraries so that these symbols are not
1092               exported between shared objects, which is not usually what's
1093               intended.
1094
1095           text
1096           notext
1097           textoff
1098               Report an error if DT_TEXTREL is set, i.e., if the position-
1099               independent or shared object has dynamic relocations in read-
1100               only sections.  Don't report an error if notext or textoff.
1101
1102           undefs
1103               Do not report unresolved symbol references from regular object
1104               files, either when creating an executable, or when creating a
1105               shared library.  This option is the inverse of -z defs.
1106
1107           unique-symbol
1108           nounique-symbol
1109               Avoid duplicated local symbol names in the symbol string table.
1110               Append "."number"" to duplicated local symbol names if unique-
1111               symbol is used.  nounique-symbol is the default.
1112
1113           x86-64-baseline
1114           x86-64-v2
1115           x86-64-v3
1116           x86-64-v4
1117               Specify the x86-64 ISA level needed in .note.gnu.property
1118               section.  x86-64-baseline generates
1119               "GNU_PROPERTY_X86_ISA_1_BASELINE".  x86-64-v2 generates
1120               "GNU_PROPERTY_X86_ISA_1_V2".  x86-64-v3 generates
1121               "GNU_PROPERTY_X86_ISA_1_V3".  x86-64-v4 generates
1122               "GNU_PROPERTY_X86_ISA_1_V4".  Supported for Linux/i386 and
1123               Linux/x86_64.
1124
1125           Other keywords are ignored for Solaris compatibility.
1126
1127       -( archives -)
1128       --start-group archives --end-group
1129           The archives should be a list of archive files.  They may be either
1130           explicit file names, or -l options.
1131
1132           The specified archives are searched repeatedly until no new
1133           undefined references are created.  Normally, an archive is searched
1134           only once in the order that it is specified on the command line.
1135           If a symbol in that archive is needed to resolve an undefined
1136           symbol referred to by an object in an archive that appears later on
1137           the command line, the linker would not be able to resolve that
1138           reference.  By grouping the archives, they will all be searched
1139           repeatedly until all possible references are resolved.
1140
1141           Using this option has a significant performance cost.  It is best
1142           to use it only when there are unavoidable circular references
1143           between two or more archives.
1144
1145       --accept-unknown-input-arch
1146       --no-accept-unknown-input-arch
1147           Tells the linker to accept input files whose architecture cannot be
1148           recognised.  The assumption is that the user knows what they are
1149           doing and deliberately wants to link in these unknown input files.
1150           This was the default behaviour of the linker, before release 2.14.
1151           The default behaviour from release 2.14 onwards is to reject such
1152           input files, and so the --accept-unknown-input-arch option has been
1153           added to restore the old behaviour.
1154
1155       --as-needed
1156       --no-as-needed
1157           This option affects ELF DT_NEEDED tags for dynamic libraries
1158           mentioned on the command line after the --as-needed option.
1159           Normally the linker will add a DT_NEEDED tag for each dynamic
1160           library mentioned on the command line, regardless of whether the
1161           library is actually needed or not.  --as-needed causes a DT_NEEDED
1162           tag to only be emitted for a library that at that point in the link
1163           satisfies a non-weak undefined symbol reference from a regular
1164           object file or, if the library is not found in the DT_NEEDED lists
1165           of other needed libraries, a non-weak undefined symbol reference
1166           from another needed dynamic library.  Object files or libraries
1167           appearing on the command line after the library in question do not
1168           affect whether the library is seen as needed.  This is similar to
1169           the rules for extraction of object files from archives.
1170           --no-as-needed restores the default behaviour.
1171
1172           Note: On Linux based systems the --as-needed option also has an
1173           affect on the behaviour of the --rpath and --rpath-link options.
1174           See the description of --rpath-link for more details.
1175
1176       --add-needed
1177       --no-add-needed
1178           These two options have been deprecated because of the similarity of
1179           their names to the --as-needed and --no-as-needed options.  They
1180           have been replaced by --copy-dt-needed-entries and
1181           --no-copy-dt-needed-entries.
1182
1183       -assert keyword
1184           This option is ignored for SunOS compatibility.
1185
1186       -Bdynamic
1187       -dy
1188       -call_shared
1189           Link against dynamic libraries.  This is only meaningful on
1190           platforms for which shared libraries are supported.  This option is
1191           normally the default on such platforms.  The different variants of
1192           this option are for compatibility with various systems.  You may
1193           use this option multiple times on the command line: it affects
1194           library searching for -l options which follow it.
1195
1196       -Bgroup
1197           Set the "DF_1_GROUP" flag in the "DT_FLAGS_1" entry in the dynamic
1198           section.  This causes the runtime linker to handle lookups in this
1199           object and its dependencies to be performed only inside the group.
1200           --unresolved-symbols=report-all is implied.  This option is only
1201           meaningful on ELF platforms which support shared libraries.
1202
1203       -Bstatic
1204       -dn
1205       -non_shared
1206       -static
1207           Do not link against shared libraries.  This is only meaningful on
1208           platforms for which shared libraries are supported.  The different
1209           variants of this option are for compatibility with various systems.
1210           You may use this option multiple times on the command line: it
1211           affects library searching for -l options which follow it.  This
1212           option also implies --unresolved-symbols=report-all.  This option
1213           can be used with -shared.  Doing so means that a shared library is
1214           being created but that all of the library's external references
1215           must be resolved by pulling in entries from static libraries.
1216
1217       -Bsymbolic
1218           When creating a shared library, bind references to global symbols
1219           to the definition within the shared library, if any.  Normally, it
1220           is possible for a program linked against a shared library to
1221           override the definition within the shared library.  This option is
1222           only meaningful on ELF platforms which support shared libraries.
1223
1224       -Bsymbolic-functions
1225           When creating a shared library, bind references to global function
1226           symbols to the definition within the shared library, if any.  This
1227           option is only meaningful on ELF platforms which support shared
1228           libraries.
1229
1230       -Bno-symbolic
1231           This option can cancel previously specified -Bsymbolic and
1232           -Bsymbolic-functions.
1233
1234       --dynamic-list=dynamic-list-file
1235           Specify the name of a dynamic list file to the linker.  This is
1236           typically used when creating shared libraries to specify a list of
1237           global symbols whose references shouldn't be bound to the
1238           definition within the shared library, or creating dynamically
1239           linked executables to specify a list of symbols which should be
1240           added to the symbol table in the executable.  This option is only
1241           meaningful on ELF platforms which support shared libraries.
1242
1243           The format of the dynamic list is the same as the version node
1244           without scope and node name.  See VERSION for more information.
1245
1246       --dynamic-list-data
1247           Include all global data symbols to the dynamic list.
1248
1249       --dynamic-list-cpp-new
1250           Provide the builtin dynamic list for C++ operator new and delete.
1251           It is mainly useful for building shared libstdc++.
1252
1253       --dynamic-list-cpp-typeinfo
1254           Provide the builtin dynamic list for C++ runtime type
1255           identification.
1256
1257       --check-sections
1258       --no-check-sections
1259           Asks the linker not to check section addresses after they have been
1260           assigned to see if there are any overlaps.  Normally the linker
1261           will perform this check, and if it finds any overlaps it will
1262           produce suitable error messages.  The linker does know about, and
1263           does make allowances for sections in overlays.  The default
1264           behaviour can be restored by using the command-line switch
1265           --check-sections.  Section overlap is not usually checked for
1266           relocatable links.  You can force checking in that case by using
1267           the --check-sections option.
1268
1269       --copy-dt-needed-entries
1270       --no-copy-dt-needed-entries
1271           This option affects the treatment of dynamic libraries referred to
1272           by DT_NEEDED tags inside ELF dynamic libraries mentioned on the
1273           command line.  Normally the linker won't add a DT_NEEDED tag to the
1274           output binary for each library mentioned in a DT_NEEDED tag in an
1275           input dynamic library.  With --copy-dt-needed-entries specified on
1276           the command line however any dynamic libraries that follow it will
1277           have their DT_NEEDED entries added.  The default behaviour can be
1278           restored with --no-copy-dt-needed-entries.
1279
1280           This option also has an effect on the resolution of symbols in
1281           dynamic libraries.  With --copy-dt-needed-entries dynamic libraries
1282           mentioned on the command line will be recursively searched,
1283           following their DT_NEEDED tags to other libraries, in order to
1284           resolve symbols required by the output binary.  With the default
1285           setting however the searching of dynamic libraries that follow it
1286           will stop with the dynamic library itself.  No DT_NEEDED links will
1287           be traversed to resolve symbols.
1288
1289       --cref
1290           Output a cross reference table.  If a linker map file is being
1291           generated, the cross reference table is printed to the map file.
1292           Otherwise, it is printed on the standard output.
1293
1294           The format of the table is intentionally simple, so that it may be
1295           easily processed by a script if necessary.  The symbols are printed
1296           out, sorted by name.  For each symbol, a list of file names is
1297           given.  If the symbol is defined, the first file listed is the
1298           location of the definition.  If the symbol is defined as a common
1299           value then any files where this happens appear next.  Finally any
1300           files that reference the symbol are listed.
1301
1302       --ctf-variables
1303       --no-ctf-variables
1304           The CTF debuginfo format supports a section which encodes the names
1305           and types of variables found in the program which do not appear in
1306           any symbol table. These variables clearly cannot be looked up by
1307           address by conventional debuggers, so the space used for their
1308           types and names is usually wasted: the types are usually small but
1309           the names are often not.  --ctf-variables causes the generation of
1310           such a section.  The default behaviour can be restored with
1311           --no-ctf-variables.
1312
1313       --ctf-share-types=method
1314           Adjust the method used to share types between translation units in
1315           CTF.
1316
1317           share-unconflicted
1318               Put all types that do not have ambiguous definitions into the
1319               shared dictionary, where debuggers can easily access them, even
1320               if they only occur in one translation unit.  This is the
1321               default.
1322
1323           share-duplicated
1324               Put only types that occur in multiple translation units into
1325               the shared dictionary: types with only one definition go into
1326               per-translation-unit dictionaries.  Types with ambiguous
1327               definitions in multiple translation units always go into per-
1328               translation-unit dictionaries.  This tends to make the CTF
1329               larger, but may reduce the amount of CTF in the shared
1330               dictionary.  For very large projects this may speed up opening
1331               the CTF and save memory in the CTF consumer at runtime.
1332
1333       --no-define-common
1334           This option inhibits the assignment of addresses to common symbols.
1335           The script command "INHIBIT_COMMON_ALLOCATION" has the same effect.
1336
1337           The --no-define-common option allows decoupling the decision to
1338           assign addresses to Common symbols from the choice of the output
1339           file type; otherwise a non-Relocatable output type forces assigning
1340           addresses to Common symbols.  Using --no-define-common allows
1341           Common symbols that are referenced from a shared library to be
1342           assigned addresses only in the main program.  This eliminates the
1343           unused duplicate space in the shared library, and also prevents any
1344           possible confusion over resolving to the wrong duplicate when there
1345           are many dynamic modules with specialized search paths for runtime
1346           symbol resolution.
1347
1348       --force-group-allocation
1349           This option causes the linker to place section group members like
1350           normal input sections, and to delete the section groups.  This is
1351           the default behaviour for a final link but this option can be used
1352           to change the behaviour of a relocatable link (-r).  The script
1353           command "FORCE_GROUP_ALLOCATION" has the same effect.
1354
1355       --defsym=symbol=expression
1356           Create a global symbol in the output file, containing the absolute
1357           address given by expression.  You may use this option as many times
1358           as necessary to define multiple symbols in the command line.  A
1359           limited form of arithmetic is supported for the expression in this
1360           context: you may give a hexadecimal constant or the name of an
1361           existing symbol, or use "+" and "-" to add or subtract hexadecimal
1362           constants or symbols.  If you need more elaborate expressions,
1363           consider using the linker command language from a script.  Note:
1364           there should be no white space between symbol, the equals sign
1365           ("="), and expression.
1366
1367           The linker processes --defsym arguments and -T arguments in order,
1368           placing --defsym before -T will define the symbol before the linker
1369           script from -T is processed, while placing --defsym after -T will
1370           define the symbol after the linker script has been processed.  This
1371           difference has consequences for expressions within the linker
1372           script that use the --defsym symbols, which order is correct will
1373           depend on what you are trying to achieve.
1374
1375       --demangle[=style]
1376       --no-demangle
1377           These options control whether to demangle symbol names in error
1378           messages and other output.  When the linker is told to demangle, it
1379           tries to present symbol names in a readable fashion: it strips
1380           leading underscores if they are used by the object file format, and
1381           converts C++ mangled symbol names into user readable names.
1382           Different compilers have different mangling styles.  The optional
1383           demangling style argument can be used to choose an appropriate
1384           demangling style for your compiler.  The linker will demangle by
1385           default unless the environment variable COLLECT_NO_DEMANGLE is set.
1386           These options may be used to override the default.
1387
1388       -Ifile
1389       --dynamic-linker=file
1390           Set the name of the dynamic linker.  This is only meaningful when
1391           generating dynamically linked ELF executables.  The default dynamic
1392           linker is normally correct; don't use this unless you know what you
1393           are doing.
1394
1395       --no-dynamic-linker
1396           When producing an executable file, omit the request for a dynamic
1397           linker to be used at load-time.  This is only meaningful for ELF
1398           executables that contain dynamic relocations, and usually requires
1399           entry point code that is capable of processing these relocations.
1400
1401       --embedded-relocs
1402           This option is similar to the --emit-relocs option except that the
1403           relocs are stored in a target-specific section.  This option is
1404           only supported by the BFIN, CR16 and M68K targets.
1405
1406       --disable-multiple-abs-defs
1407           Do not allow multiple definitions with symbols included in filename
1408           invoked by -R or --just-symbols
1409
1410       --fatal-warnings
1411       --no-fatal-warnings
1412           Treat all warnings as errors.  The default behaviour can be
1413           restored with the option --no-fatal-warnings.
1414
1415       --force-exe-suffix
1416           Make sure that an output file has a .exe suffix.
1417
1418           If a successfully built fully linked output file does not have a
1419           ".exe" or ".dll" suffix, this option forces the linker to copy the
1420           output file to one of the same name with a ".exe" suffix. This
1421           option is useful when using unmodified Unix makefiles on a
1422           Microsoft Windows host, since some versions of Windows won't run an
1423           image unless it ends in a ".exe" suffix.
1424
1425       --gc-sections
1426       --no-gc-sections
1427           Enable garbage collection of unused input sections.  It is ignored
1428           on targets that do not support this option.  The default behaviour
1429           (of not performing this garbage collection) can be restored by
1430           specifying --no-gc-sections on the command line.  Note that garbage
1431           collection for COFF and PE format targets is supported, but the
1432           implementation is currently considered to be experimental.
1433
1434           --gc-sections decides which input sections are used by examining
1435           symbols and relocations.  The section containing the entry symbol
1436           and all sections containing symbols undefined on the command-line
1437           will be kept, as will sections containing symbols referenced by
1438           dynamic objects.  Note that when building shared libraries, the
1439           linker must assume that any visible symbol is referenced.  Once
1440           this initial set of sections has been determined, the linker
1441           recursively marks as used any section referenced by their
1442           relocations.  See --entry, --undefined, and --gc-keep-exported.
1443
1444           This option can be set when doing a partial link (enabled with
1445           option -r).  In this case the root of symbols kept must be
1446           explicitly specified either by one of the options --entry,
1447           --undefined, or --gc-keep-exported or by a "ENTRY" command in the
1448           linker script.
1449
1450           As a GNU extension, ELF input sections marked with the
1451           "SHF_GNU_RETAIN" flag will not be garbage collected.
1452
1453       --print-gc-sections
1454       --no-print-gc-sections
1455           List all sections removed by garbage collection.  The listing is
1456           printed on stderr.  This option is only effective if garbage
1457           collection has been enabled via the --gc-sections) option.  The
1458           default behaviour (of not listing the sections that are removed)
1459           can be restored by specifying --no-print-gc-sections on the command
1460           line.
1461
1462       --gc-keep-exported
1463           When --gc-sections is enabled, this option prevents garbage
1464           collection of unused input sections that contain global symbols
1465           having default or protected visibility.  This option is intended to
1466           be used for executables where unreferenced sections would otherwise
1467           be garbage collected regardless of the external visibility of
1468           contained symbols.  Note that this option has no effect when
1469           linking shared objects since it is already the default behaviour.
1470           This option is only supported for ELF format targets.
1471
1472       --print-output-format
1473           Print the name of the default output format (perhaps influenced by
1474           other command-line options).  This is the string that would appear
1475           in an "OUTPUT_FORMAT" linker script command.
1476
1477       --print-memory-usage
1478           Print used size, total size and used size of memory regions created
1479           with the MEMORY command.  This is useful on embedded targets to
1480           have a quick view of amount of free memory.  The format of the
1481           output has one headline and one line per region.  It is both human
1482           readable and easily parsable by tools.  Here is an example of an
1483           output:
1484
1485                   Memory region         Used Size  Region Size  %age Used
1486                                ROM:        256 KB         1 MB     25.00%
1487                                RAM:          32 B         2 GB      0.00%
1488
1489       --help
1490           Print a summary of the command-line options on the standard output
1491           and exit.
1492
1493       --target-help
1494           Print a summary of all target-specific options on the standard
1495           output and exit.
1496
1497       -Map=mapfile
1498           Print a link map to the file mapfile.  See the description of the
1499           -M option, above.  If mapfile is just the character "-" then the
1500           map will be written to stdout.
1501
1502           Specifying a directory as mapfile causes the linker map to be
1503           written as a file inside the directory.  Normally name of the file
1504           inside the directory is computed as the basename of the output file
1505           with ".map" appended.   If however the special character "%" is
1506           used then this will be replaced by the full path of the output
1507           file.  Additionally if there are any characters after the % symbol
1508           then ".map" will no longer be appended.
1509
1510                    -o foo.exe -Map=bar                  [Creates ./bar]
1511                    -o ../dir/foo.exe -Map=bar           [Creates ./bar]
1512                    -o foo.exe -Map=../dir               [Creates ../dir/foo.exe.map]
1513                    -o ../dir2/foo.exe -Map=../dir       [Creates ../dir/foo.exe.map]
1514                    -o foo.exe -Map=%                    [Creates ./foo.exe.map]
1515                    -o ../dir/foo.exe -Map=%             [Creates ../dir/foo.exe.map]
1516                    -o foo.exe -Map=%.bar                [Creates ./foo.exe.bar]
1517                    -o ../dir/foo.exe -Map=%.bar         [Creates ../dir/foo.exe.bar]
1518                    -o ../dir2/foo.exe -Map=../dir/%     [Creates ../dir/../dir2/foo.exe.map]
1519                    -o ../dir2/foo.exe -Map=../dir/%.bar [Creates ../dir/../dir2/foo.exe.bar]
1520
1521           It is an error to specify more than one "%" character.
1522
1523           If the map file already exists then it will be overwritten by this
1524           operation.
1525
1526       --no-keep-memory
1527           ld normally optimizes for speed over memory usage by caching the
1528           symbol tables of input files in memory.  This option tells ld to
1529           instead optimize for memory usage, by rereading the symbol tables
1530           as necessary.  This may be required if ld runs out of memory space
1531           while linking a large executable.
1532
1533       --no-undefined
1534       -z defs
1535           Report unresolved symbol references from regular object files.
1536           This is done even if the linker is creating a non-symbolic shared
1537           library.  The switch --[no-]allow-shlib-undefined controls the
1538           behaviour for reporting unresolved references found in shared
1539           libraries being linked in.
1540
1541           The effects of this option can be reverted by using "-z undefs".
1542
1543       --allow-multiple-definition
1544       -z muldefs
1545           Normally when a symbol is defined multiple times, the linker will
1546           report a fatal error. These options allow multiple definitions and
1547           the first definition will be used.
1548
1549       --allow-shlib-undefined
1550       --no-allow-shlib-undefined
1551           Allows or disallows undefined symbols in shared libraries.  This
1552           switch is similar to --no-undefined except that it determines the
1553           behaviour when the undefined symbols are in a shared library rather
1554           than a regular object file.  It does not affect how undefined
1555           symbols in regular object files are handled.
1556
1557           The default behaviour is to report errors for any undefined symbols
1558           referenced in shared libraries if the linker is being used to
1559           create an executable, but to allow them if the linker is being used
1560           to create a shared library.
1561
1562           The reasons for allowing undefined symbol references in shared
1563           libraries specified at link time are that:
1564
1565           •   A shared library specified at link time may not be the same as
1566               the one that is available at load time, so the symbol might
1567               actually be resolvable at load time.
1568
1569           •   There are some operating systems, eg BeOS and HPPA, where
1570               undefined symbols in shared libraries are normal.
1571
1572               The BeOS kernel for example patches shared libraries at load
1573               time to select whichever function is most appropriate for the
1574               current architecture.  This is used, for example, to
1575               dynamically select an appropriate memset function.
1576
1577       --error-handling-script=scriptname
1578           If this option is provided then the linker will invoke scriptname
1579           whenever an error is encountered.  Currently however only two kinds
1580           of error are supported: missing symbols and missing libraries.  Two
1581           arguments will be passed to script: the keyword "undefined-symbol"
1582           or `missing-lib" and the name of the undefined symbol or missing
1583           library.  The intention is that the script will provide suggestions
1584           to the user as to where the symbol or library might be found.
1585           After the script has finished then the normal linker error message
1586           will be displayed.
1587
1588           The availability of this option is controlled by a configure time
1589           switch, so it may not be present in specific implementations.
1590
1591       --no-undefined-version
1592           Normally when a symbol has an undefined version, the linker will
1593           ignore it. This option disallows symbols with undefined version and
1594           a fatal error will be issued instead.
1595
1596       --default-symver
1597           Create and use a default symbol version (the soname) for
1598           unversioned exported symbols.
1599
1600       --default-imported-symver
1601           Create and use a default symbol version (the soname) for
1602           unversioned imported symbols.
1603
1604       --no-warn-mismatch
1605           Normally ld will give an error if you try to link together input
1606           files that are mismatched for some reason, perhaps because they
1607           have been compiled for different processors or for different
1608           endiannesses.  This option tells ld that it should silently permit
1609           such possible errors.  This option should only be used with care,
1610           in cases when you have taken some special action that ensures that
1611           the linker errors are inappropriate.
1612
1613       --no-warn-search-mismatch
1614           Normally ld will give a warning if it finds an incompatible library
1615           during a library search.  This option silences the warning.
1616
1617       --no-whole-archive
1618           Turn off the effect of the --whole-archive option for subsequent
1619           archive files.
1620
1621       --noinhibit-exec
1622           Retain the executable output file whenever it is still usable.
1623           Normally, the linker will not produce an output file if it
1624           encounters errors during the link process; it exits without writing
1625           an output file when it issues any error whatsoever.
1626
1627       -nostdlib
1628           Only search library directories explicitly specified on the command
1629           line.  Library directories specified in linker scripts (including
1630           linker scripts specified on the command line) are ignored.
1631
1632       --oformat=output-format
1633           ld may be configured to support more than one kind of object file.
1634           If your ld is configured this way, you can use the --oformat option
1635           to specify the binary format for the output object file.  Even when
1636           ld is configured to support alternative object formats, you don't
1637           usually need to specify this, as ld should be configured to produce
1638           as a default output format the most usual format on each machine.
1639           output-format is a text string, the name of a particular format
1640           supported by the BFD libraries.  (You can list the available binary
1641           formats with objdump -i.)  The script command "OUTPUT_FORMAT" can
1642           also specify the output format, but this option overrides it.
1643
1644       --out-implib file
1645           Create an import library in file corresponding to the executable
1646           the linker is generating (eg. a DLL or ELF program).  This import
1647           library (which should be called "*.dll.a" or "*.a" for DLLs) may be
1648           used to link clients against the generated executable; this
1649           behaviour makes it possible to skip a separate import library
1650           creation step (eg. "dlltool" for DLLs).  This option is only
1651           available for the i386 PE and ELF targetted ports of the linker.
1652
1653       -pie
1654       --pic-executable
1655           Create a position independent executable.  This is currently only
1656           supported on ELF platforms.  Position independent executables are
1657           similar to shared libraries in that they are relocated by the
1658           dynamic linker to the virtual address the OS chooses for them
1659           (which can vary between invocations).  Like normal dynamically
1660           linked executables they can be executed and symbols defined in the
1661           executable cannot be overridden by shared libraries.
1662
1663       -no-pie
1664           Create a position dependent executable.  This is the default.
1665
1666       -qmagic
1667           This option is ignored for Linux compatibility.
1668
1669       -Qy This option is ignored for SVR4 compatibility.
1670
1671       --relax
1672       --no-relax
1673           An option with machine dependent effects.  This option is only
1674           supported on a few targets.
1675
1676           On some platforms the --relax option performs target specific,
1677           global optimizations that become possible when the linker resolves
1678           addressing in the program, such as relaxing address modes,
1679           synthesizing new instructions, selecting shorter version of current
1680           instructions, and combining constant values.
1681
1682           On some platforms these link time global optimizations may make
1683           symbolic debugging of the resulting executable impossible.  This is
1684           known to be the case for the Matsushita MN10200 and MN10300 family
1685           of processors.
1686
1687           On platforms where the feature is supported, the option --no-relax
1688           will disable it.
1689
1690           On platforms where the feature is not supported, both --relax and
1691           --no-relax are accepted, but ignored.
1692
1693       --retain-symbols-file=filename
1694           Retain only the symbols listed in the file filename, discarding all
1695           others.  filename is simply a flat file, with one symbol name per
1696           line.  This option is especially useful in environments (such as
1697           VxWorks) where a large global symbol table is accumulated
1698           gradually, to conserve run-time memory.
1699
1700           --retain-symbols-file does not discard undefined symbols, or
1701           symbols needed for relocations.
1702
1703           You may only specify --retain-symbols-file once in the command
1704           line.  It overrides -s and -S.
1705
1706       -rpath=dir
1707           Add a directory to the runtime library search path.  This is used
1708           when linking an ELF executable with shared objects.  All -rpath
1709           arguments are concatenated and passed to the runtime linker, which
1710           uses them to locate shared objects at runtime.
1711
1712           The -rpath option is also used when locating shared objects which
1713           are needed by shared objects explicitly included in the link; see
1714           the description of the -rpath-link option.  Searching -rpath in
1715           this way is only supported by native linkers and cross linkers
1716           which have been configured with the --with-sysroot option.
1717
1718           If -rpath is not used when linking an ELF executable, the contents
1719           of the environment variable "LD_RUN_PATH" will be used if it is
1720           defined.
1721
1722           The -rpath option may also be used on SunOS.  By default, on SunOS,
1723           the linker will form a runtime search path out of all the -L
1724           options it is given.  If a -rpath option is used, the runtime
1725           search path will be formed exclusively using the -rpath options,
1726           ignoring the -L options.  This can be useful when using gcc, which
1727           adds many -L options which may be on NFS mounted file systems.
1728
1729           For compatibility with other ELF linkers, if the -R option is
1730           followed by a directory name, rather than a file name, it is
1731           treated as the -rpath option.
1732
1733       -rpath-link=dir
1734           When using ELF or SunOS, one shared library may require another.
1735           This happens when an "ld -shared" link includes a shared library as
1736           one of the input files.
1737
1738           When the linker encounters such a dependency when doing a non-
1739           shared, non-relocatable link, it will automatically try to locate
1740           the required shared library and include it in the link, if it is
1741           not included explicitly.  In such a case, the -rpath-link option
1742           specifies the first set of directories to search.  The -rpath-link
1743           option may specify a sequence of directory names either by
1744           specifying a list of names separated by colons, or by appearing
1745           multiple times.
1746
1747           The tokens $ORIGIN and $LIB can appear in these search directories.
1748           They will be replaced by the full path to the directory containing
1749           the program or shared object in the case of $ORIGIN and either lib
1750           - for 32-bit binaries - or lib64 - for 64-bit binaries - in the
1751           case of $LIB.
1752
1753           The alternative form of these tokens - ${ORIGIN} and ${LIB} can
1754           also be used.  The token $PLATFORM is not supported.
1755
1756           This option should be used with caution as it overrides the search
1757           path that may have been hard compiled into a shared library. In
1758           such a case it is possible to use unintentionally a different
1759           search path than the runtime linker would do.
1760
1761           The linker uses the following search paths to locate required
1762           shared libraries:
1763
1764           1.  Any directories specified by -rpath-link options.
1765
1766           2.  Any directories specified by -rpath options.  The difference
1767               between -rpath and -rpath-link is that directories specified by
1768               -rpath options are included in the executable and used at
1769               runtime, whereas the -rpath-link option is only effective at
1770               link time. Searching -rpath in this way is only supported by
1771               native linkers and cross linkers which have been configured
1772               with the --with-sysroot option.
1773
1774           3.  On an ELF system, for native linkers, if the -rpath and
1775               -rpath-link options were not used, search the contents of the
1776               environment variable "LD_RUN_PATH".
1777
1778           4.  On SunOS, if the -rpath option was not used, search any
1779               directories specified using -L options.
1780
1781           5.  For a native linker, search the contents of the environment
1782               variable "LD_LIBRARY_PATH".
1783
1784           6.  For a native ELF linker, the directories in "DT_RUNPATH" or
1785               "DT_RPATH" of a shared library are searched for shared
1786               libraries needed by it. The "DT_RPATH" entries are ignored if
1787               "DT_RUNPATH" entries exist.
1788
1789           7.  For a linker for a Linux system, if the file /etc/ld.so.conf
1790               exists, the list of directories found in that file.  Note: the
1791               path to this file is prefixed with the "sysroot" value, if that
1792               is defined, and then any "prefix" string if the linker was
1793               configured with the --prefix=<path> option.
1794
1795           8.  For a native linker on a FreeBSD system, any directories
1796               specified by the "_PATH_ELF_HINTS" macro defined in the
1797               elf-hints.h header file.
1798
1799           9.  Any directories specified by a "SEARCH_DIR" command in a linker
1800               script given on the command line, including scripts specified
1801               by -T (but not -dT).
1802
1803           10. The default directories, normally /lib and /usr/lib.
1804
1805           11. Any directories specified by a plugin
1806               LDPT_SET_EXTRA_LIBRARY_PATH.
1807
1808           12. Any directories specified by a "SEARCH_DIR" command in a
1809               default linker script.
1810
1811           Note however on Linux based systems there is an additional caveat:
1812           If the --as-needed option is active and a shared library is located
1813           which would normally satisfy the search and this library does not
1814           have DT_NEEDED tag for libc.so and there is a shared library later
1815           on in the set of search directories which also satisfies the search
1816           and this second shared library does have a DT_NEEDED tag for
1817           libc.so then the second library will be selected instead of the
1818           first.
1819
1820           If the required shared library is not found, the linker will issue
1821           a warning and continue with the link.
1822
1823       -shared
1824       -Bshareable
1825           Create a shared library.  This is currently only supported on ELF,
1826           XCOFF and SunOS platforms.  On SunOS, the linker will automatically
1827           create a shared library if the -e option is not used and there are
1828           undefined symbols in the link.
1829
1830       --sort-common
1831       --sort-common=ascending
1832       --sort-common=descending
1833           This option tells ld to sort the common symbols by alignment in
1834           ascending or descending order when it places them in the
1835           appropriate output sections.  The symbol alignments considered are
1836           sixteen-byte or larger, eight-byte, four-byte, two-byte, and one-
1837           byte. This is to prevent gaps between symbols due to alignment
1838           constraints.  If no sorting order is specified, then descending
1839           order is assumed.
1840
1841       --sort-section=name
1842           This option will apply "SORT_BY_NAME" to all wildcard section
1843           patterns in the linker script.
1844
1845       --sort-section=alignment
1846           This option will apply "SORT_BY_ALIGNMENT" to all wildcard section
1847           patterns in the linker script.
1848
1849       --spare-dynamic-tags=count
1850           This option specifies the number of empty slots to leave in the
1851           .dynamic section of ELF shared objects.  Empty slots may be needed
1852           by post processing tools, such as the prelinker.  The default is 5.
1853
1854       --split-by-file[=size]
1855           Similar to --split-by-reloc but creates a new output section for
1856           each input file when size is reached.  size defaults to a size of 1
1857           if not given.
1858
1859       --split-by-reloc[=count]
1860           Tries to creates extra sections in the output file so that no
1861           single output section in the file contains more than count
1862           relocations.  This is useful when generating huge relocatable files
1863           for downloading into certain real time kernels with the COFF object
1864           file format; since COFF cannot represent more than 65535
1865           relocations in a single section.  Note that this will fail to work
1866           with object file formats which do not support arbitrary sections.
1867           The linker will not split up individual input sections for
1868           redistribution, so if a single input section contains more than
1869           count relocations one output section will contain that many
1870           relocations.  count defaults to a value of 32768.
1871
1872       --stats
1873           Compute and display statistics about the operation of the linker,
1874           such as execution time and memory usage.
1875
1876       --sysroot=directory
1877           Use directory as the location of the sysroot, overriding the
1878           configure-time default.  This option is only supported by linkers
1879           that were configured using --with-sysroot.
1880
1881       --task-link
1882           This is used by COFF/PE based targets to create a task-linked
1883           object file where all of the global symbols have been converted to
1884           statics.
1885
1886       --traditional-format
1887           For some targets, the output of ld is different in some ways from
1888           the output of some existing linker.  This switch requests ld to use
1889           the traditional format instead.
1890
1891           For example, on SunOS, ld combines duplicate entries in the symbol
1892           string table.  This can reduce the size of an output file with full
1893           debugging information by over 30 percent.  Unfortunately, the SunOS
1894           "dbx" program can not read the resulting program ("gdb" has no
1895           trouble).  The --traditional-format switch tells ld to not combine
1896           duplicate entries.
1897
1898       --section-start=sectionname=org
1899           Locate a section in the output file at the absolute address given
1900           by org.  You may use this option as many times as necessary to
1901           locate multiple sections in the command line.  org must be a single
1902           hexadecimal integer; for compatibility with other linkers, you may
1903           omit the leading 0x usually associated with hexadecimal values.
1904           Note: there should be no white space between sectionname, the
1905           equals sign ("="), and org.
1906
1907       -Tbss=org
1908       -Tdata=org
1909       -Ttext=org
1910           Same as --section-start, with ".bss", ".data" or ".text" as the
1911           sectionname.
1912
1913       -Ttext-segment=org
1914           When creating an ELF executable, it will set the address of the
1915           first byte of the text segment.
1916
1917       -Trodata-segment=org
1918           When creating an ELF executable or shared object for a target where
1919           the read-only data is in its own segment separate from the
1920           executable text, it will set the address of the first byte of the
1921           read-only data segment.
1922
1923       -Tldata-segment=org
1924           When creating an ELF executable or shared object for x86-64 medium
1925           memory model, it will set the address of the first byte of the
1926           ldata segment.
1927
1928       --unresolved-symbols=method
1929           Determine how to handle unresolved symbols.  There are four
1930           possible values for method:
1931
1932           ignore-all
1933               Do not report any unresolved symbols.
1934
1935           report-all
1936               Report all unresolved symbols.  This is the default.
1937
1938           ignore-in-object-files
1939               Report unresolved symbols that are contained in shared
1940               libraries, but ignore them if they come from regular object
1941               files.
1942
1943           ignore-in-shared-libs
1944               Report unresolved symbols that come from regular object files,
1945               but ignore them if they come from shared libraries.  This can
1946               be useful when creating a dynamic binary and it is known that
1947               all the shared libraries that it should be referencing are
1948               included on the linker's command line.
1949
1950           The behaviour for shared libraries on their own can also be
1951           controlled by the --[no-]allow-shlib-undefined option.
1952
1953           Normally the linker will generate an error message for each
1954           reported unresolved symbol but the option --warn-unresolved-symbols
1955           can change this to a warning.
1956
1957       --dll-verbose
1958       --verbose[=NUMBER]
1959           Display the version number for ld and list the linker emulations
1960           supported.  Display which input files can and cannot be opened.
1961           Display the linker script being used by the linker. If the optional
1962           NUMBER argument > 1, plugin symbol status will also be displayed.
1963
1964       --version-script=version-scriptfile
1965           Specify the name of a version script to the linker.  This is
1966           typically used when creating shared libraries to specify additional
1967           information about the version hierarchy for the library being
1968           created.  This option is only fully supported on ELF platforms
1969           which support shared libraries; see VERSION.  It is partially
1970           supported on PE platforms, which can use version scripts to filter
1971           symbol visibility in auto-export mode: any symbols marked local in
1972           the version script will not be exported.
1973
1974       --warn-common
1975           Warn when a common symbol is combined with another common symbol or
1976           with a symbol definition.  Unix linkers allow this somewhat sloppy
1977           practice, but linkers on some other operating systems do not.  This
1978           option allows you to find potential problems from combining global
1979           symbols.  Unfortunately, some C libraries use this practice, so you
1980           may get some warnings about symbols in the libraries as well as in
1981           your programs.
1982
1983           There are three kinds of global symbols, illustrated here by C
1984           examples:
1985
1986           int i = 1;
1987               A definition, which goes in the initialized data section of the
1988               output file.
1989
1990           extern int i;
1991               An undefined reference, which does not allocate space.  There
1992               must be either a definition or a common symbol for the variable
1993               somewhere.
1994
1995           int i;
1996               A common symbol.  If there are only (one or more) common
1997               symbols for a variable, it goes in the uninitialized data area
1998               of the output file.  The linker merges multiple common symbols
1999               for the same variable into a single symbol.  If they are of
2000               different sizes, it picks the largest size.  The linker turns a
2001               common symbol into a declaration, if there is a definition of
2002               the same variable.
2003
2004           The --warn-common option can produce five kinds of warnings.  Each
2005           warning consists of a pair of lines: the first describes the symbol
2006           just encountered, and the second describes the previous symbol
2007           encountered with the same name.  One or both of the two symbols
2008           will be a common symbol.
2009
2010           1.  Turning a common symbol into a reference, because there is
2011               already a definition for the symbol.
2012
2013                       <file>(<section>): warning: common of `<symbol>'
2014                          overridden by definition
2015                       <file>(<section>): warning: defined here
2016
2017           2.  Turning a common symbol into a reference, because a later
2018               definition for the symbol is encountered.  This is the same as
2019               the previous case, except that the symbols are encountered in a
2020               different order.
2021
2022                       <file>(<section>): warning: definition of `<symbol>'
2023                          overriding common
2024                       <file>(<section>): warning: common is here
2025
2026           3.  Merging a common symbol with a previous same-sized common
2027               symbol.
2028
2029                       <file>(<section>): warning: multiple common
2030                          of `<symbol>'
2031                       <file>(<section>): warning: previous common is here
2032
2033           4.  Merging a common symbol with a previous larger common symbol.
2034
2035                       <file>(<section>): warning: common of `<symbol>'
2036                          overridden by larger common
2037                       <file>(<section>): warning: larger common is here
2038
2039           5.  Merging a common symbol with a previous smaller common symbol.
2040               This is the same as the previous case, except that the symbols
2041               are encountered in a different order.
2042
2043                       <file>(<section>): warning: common of `<symbol>'
2044                          overriding smaller common
2045                       <file>(<section>): warning: smaller common is here
2046
2047       --warn-constructors
2048           Warn if any global constructors are used.  This is only useful for
2049           a few object file formats.  For formats like COFF or ELF, the
2050           linker can not detect the use of global constructors.
2051
2052       --warn-multiple-gp
2053           Warn if multiple global pointer values are required in the output
2054           file.  This is only meaningful for certain processors, such as the
2055           Alpha.  Specifically, some processors put large-valued constants in
2056           a special section.  A special register (the global pointer) points
2057           into the middle of this section, so that constants can be loaded
2058           efficiently via a base-register relative addressing mode.  Since
2059           the offset in base-register relative mode is fixed and relatively
2060           small (e.g., 16 bits), this limits the maximum size of the constant
2061           pool.  Thus, in large programs, it is often necessary to use
2062           multiple global pointer values in order to be able to address all
2063           possible constants.  This option causes a warning to be issued
2064           whenever this case occurs.
2065
2066       --warn-once
2067           Only warn once for each undefined symbol, rather than once per
2068           module which refers to it.
2069
2070       --warn-section-align
2071           Warn if the address of an output section is changed because of
2072           alignment.  Typically, the alignment will be set by an input
2073           section.  The address will only be changed if it not explicitly
2074           specified; that is, if the "SECTIONS" command does not specify a
2075           start address for the section.
2076
2077       --warn-textrel
2078           Warn if the linker adds DT_TEXTREL to a position-independent
2079           executable or shared object.
2080
2081       --warn-alternate-em
2082           Warn if an object has alternate ELF machine code.
2083
2084       --warn-unresolved-symbols
2085           If the linker is going to report an unresolved symbol (see the
2086           option --unresolved-symbols) it will normally generate an error.
2087           This option makes it generate a warning instead.
2088
2089       --error-unresolved-symbols
2090           This restores the linker's default behaviour of generating errors
2091           when it is reporting unresolved symbols.
2092
2093       --whole-archive
2094           For each archive mentioned on the command line after the
2095           --whole-archive option, include every object file in the archive in
2096           the link, rather than searching the archive for the required object
2097           files.  This is normally used to turn an archive file into a shared
2098           library, forcing every object to be included in the resulting
2099           shared library.  This option may be used more than once.
2100
2101           Two notes when using this option from gcc: First, gcc doesn't know
2102           about this option, so you have to use -Wl,-whole-archive.  Second,
2103           don't forget to use -Wl,-no-whole-archive after your list of
2104           archives, because gcc will add its own list of archives to your
2105           link and you may not want this flag to affect those as well.
2106
2107       --wrap=symbol
2108           Use a wrapper function for symbol.  Any undefined reference to
2109           symbol will be resolved to "__wrap_symbol".  Any undefined
2110           reference to "__real_symbol" will be resolved to symbol.
2111
2112           This can be used to provide a wrapper for a system function.  The
2113           wrapper function should be called "__wrap_symbol".  If it wishes to
2114           call the system function, it should call "__real_symbol".
2115
2116           Here is a trivial example:
2117
2118                   void *
2119                   __wrap_malloc (size_t c)
2120                   {
2121                     printf ("malloc called with %zu\n", c);
2122                     return __real_malloc (c);
2123                   }
2124
2125           If you link other code with this file using --wrap malloc, then all
2126           calls to "malloc" will call the function "__wrap_malloc" instead.
2127           The call to "__real_malloc" in "__wrap_malloc" will call the real
2128           "malloc" function.
2129
2130           You may wish to provide a "__real_malloc" function as well, so that
2131           links without the --wrap option will succeed.  If you do this, you
2132           should not put the definition of "__real_malloc" in the same file
2133           as "__wrap_malloc"; if you do, the assembler may resolve the call
2134           before the linker has a chance to wrap it to "malloc".
2135
2136           Only undefined references are replaced by the linker.  So,
2137           translation unit internal references to symbol are not resolved to
2138           "__wrap_symbol".  In the next example, the call to "f" in "g" is
2139           not resolved to "__wrap_f".
2140
2141                   int
2142                   f (void)
2143                   {
2144                     return 123;
2145                   }
2146
2147                   int
2148                   g (void)
2149                   {
2150                     return f();
2151                   }
2152
2153       --eh-frame-hdr
2154       --no-eh-frame-hdr
2155           Request (--eh-frame-hdr) or suppress (--no-eh-frame-hdr) the
2156           creation of ".eh_frame_hdr" section and ELF "PT_GNU_EH_FRAME"
2157           segment header.
2158
2159       --no-ld-generated-unwind-info
2160           Request creation of ".eh_frame" unwind info for linker generated
2161           code sections like PLT.  This option is on by default if linker
2162           generated unwind info is supported.
2163
2164       --enable-new-dtags
2165       --disable-new-dtags
2166           This linker can create the new dynamic tags in ELF. But the older
2167           ELF systems may not understand them. If you specify
2168           --enable-new-dtags, the new dynamic tags will be created as needed
2169           and older dynamic tags will be omitted.  If you specify
2170           --disable-new-dtags, no new dynamic tags will be created. By
2171           default, the new dynamic tags are not created. Note that those
2172           options are only available for ELF systems.
2173
2174       --hash-size=number
2175           Set the default size of the linker's hash tables to a prime number
2176           close to number.  Increasing this value can reduce the length of
2177           time it takes the linker to perform its tasks, at the expense of
2178           increasing the linker's memory requirements.  Similarly reducing
2179           this value can reduce the memory requirements at the expense of
2180           speed.
2181
2182       --hash-style=style
2183           Set the type of linker's hash table(s).  style can be either "sysv"
2184           for classic ELF ".hash" section, "gnu" for new style GNU
2185           ".gnu.hash" section or "both" for both the classic ELF ".hash" and
2186           new style GNU ".gnu.hash" hash tables.  The default depends upon
2187           how the linker was configured, but for most Linux based systems it
2188           will be "both".
2189
2190       --compress-debug-sections=none
2191       --compress-debug-sections=zlib
2192       --compress-debug-sections=zlib-gnu
2193       --compress-debug-sections=zlib-gabi
2194           On ELF platforms, these options control how DWARF debug sections
2195           are compressed using zlib.
2196
2197           --compress-debug-sections=none doesn't compress DWARF debug
2198           sections.  --compress-debug-sections=zlib-gnu compresses DWARF
2199           debug sections and renames them to begin with .zdebug instead of
2200           .debug.  --compress-debug-sections=zlib-gabi also compresses DWARF
2201           debug sections, but rather than renaming them it sets the
2202           SHF_COMPRESSED flag in the sections' headers.
2203
2204           The --compress-debug-sections=zlib option is an alias for
2205           --compress-debug-sections=zlib-gabi.
2206
2207           Note that this option overrides any compression in input debug
2208           sections, so if a binary is linked with
2209           --compress-debug-sections=none for example, then any compressed
2210           debug sections in input files will be uncompressed before they are
2211           copied into the output binary.
2212
2213           The default compression behaviour varies depending upon the target
2214           involved and the configure options used to build the toolchain.
2215           The default can be determined by examining the output from the
2216           linker's --help option.
2217
2218       --reduce-memory-overheads
2219           This option reduces memory requirements at ld runtime, at the
2220           expense of linking speed.  This was introduced to select the old
2221           O(n^2) algorithm for link map file generation, rather than the new
2222           O(n) algorithm which uses about 40% more memory for symbol storage.
2223
2224           Another effect of the switch is to set the default hash table size
2225           to 1021, which again saves memory at the cost of lengthening the
2226           linker's run time.  This is not done however if the --hash-size
2227           switch has been used.
2228
2229           The --reduce-memory-overheads switch may be also be used to enable
2230           other tradeoffs in future versions of the linker.
2231
2232       --max-cache-size=size
2233           ld normally caches the relocation information and symbol tables of
2234           input files in memory with the unlimited size.  This option sets
2235           the maximum cache size to size.
2236
2237       --build-id
2238       --build-id=style
2239           Request the creation of a ".note.gnu.build-id" ELF note section or
2240           a ".buildid" COFF section.  The contents of the note are unique
2241           bits identifying this linked file.  style can be "uuid" to use 128
2242           random bits, "sha1" to use a 160-bit SHA1 hash on the normative
2243           parts of the output contents, "md5" to use a 128-bit MD5 hash on
2244           the normative parts of the output contents, or "0xhexstring" to use
2245           a chosen bit string specified as an even number of hexadecimal
2246           digits ("-" and ":" characters between digit pairs are ignored).
2247           If style is omitted, "sha1" is used.
2248
2249           The "md5" and "sha1" styles produces an identifier that is always
2250           the same in an identical output file, but will be unique among all
2251           nonidentical output files.  It is not intended to be compared as a
2252           checksum for the file's contents.  A linked file may be changed
2253           later by other tools, but the build ID bit string identifying the
2254           original linked file does not change.
2255
2256           Passing "none" for style disables the setting from any "--build-id"
2257           options earlier on the command line.
2258
2259       --package-metadata=JSON
2260           Request the creation of a ".note.package" ELF note section.  The
2261           contents of the note are in JSON format, as per the package
2262           metadata specification.  For more information see:
2263           https://systemd.io/ELF_PACKAGE_METADATA/ If the JSON argument is
2264           missing/empty then this will disable the creation of the metadata
2265           note, if one had been enabled by an earlier occurrence of the
2266           --package-metdata option.  If the linker has been built with
2267           libjansson, then the JSON string will be validated.
2268
2269       The i386 PE linker supports the -shared option, which causes the output
2270       to be a dynamically linked library (DLL) instead of a normal
2271       executable.  You should name the output "*.dll" when you use this
2272       option.  In addition, the linker fully supports the standard "*.def"
2273       files, which may be specified on the linker command line like an object
2274       file (in fact, it should precede archives it exports symbols from, to
2275       ensure that they get linked in, just like a normal object file).
2276
2277       In addition to the options common to all targets, the i386 PE linker
2278       support additional command-line options that are specific to the i386
2279       PE target.  Options that take values may be separated from their values
2280       by either a space or an equals sign.
2281
2282       --add-stdcall-alias
2283           If given, symbols with a stdcall suffix (@nn) will be exported as-
2284           is and also with the suffix stripped.  [This option is specific to
2285           the i386 PE targeted port of the linker]
2286
2287       --base-file file
2288           Use file as the name of a file in which to save the base addresses
2289           of all the relocations needed for generating DLLs with dlltool.
2290           [This is an i386 PE specific option]
2291
2292       --dll
2293           Create a DLL instead of a regular executable.  You may also use
2294           -shared or specify a "LIBRARY" in a given ".def" file.  [This
2295           option is specific to the i386 PE targeted port of the linker]
2296
2297       --enable-long-section-names
2298       --disable-long-section-names
2299           The PE variants of the COFF object format add an extension that
2300           permits the use of section names longer than eight characters, the
2301           normal limit for COFF.  By default, these names are only allowed in
2302           object files, as fully-linked executable images do not carry the
2303           COFF string table required to support the longer names.  As a GNU
2304           extension, it is possible to allow their use in executable images
2305           as well, or to (probably pointlessly!)  disallow it in object
2306           files, by using these two options.  Executable images generated
2307           with these long section names are slightly non-standard, carrying
2308           as they do a string table, and may generate confusing output when
2309           examined with non-GNU PE-aware tools, such as file viewers and
2310           dumpers.  However, GDB relies on the use of PE long section names
2311           to find Dwarf-2 debug information sections in an executable image
2312           at runtime, and so if neither option is specified on the command-
2313           line, ld will enable long section names, overriding the default and
2314           technically correct behaviour, when it finds the presence of debug
2315           information while linking an executable image and not stripping
2316           symbols.  [This option is valid for all PE targeted ports of the
2317           linker]
2318
2319       --enable-stdcall-fixup
2320       --disable-stdcall-fixup
2321           If the link finds a symbol that it cannot resolve, it will attempt
2322           to do "fuzzy linking" by looking for another defined symbol that
2323           differs only in the format of the symbol name (cdecl vs stdcall)
2324           and will resolve that symbol by linking to the match.  For example,
2325           the undefined symbol "_foo" might be linked to the function
2326           "_foo@12", or the undefined symbol "_bar@16" might be linked to the
2327           function "_bar".  When the linker does this, it prints a warning,
2328           since it normally should have failed to link, but sometimes import
2329           libraries generated from third-party dlls may need this feature to
2330           be usable.  If you specify --enable-stdcall-fixup, this feature is
2331           fully enabled and warnings are not printed.  If you specify
2332           --disable-stdcall-fixup, this feature is disabled and such
2333           mismatches are considered to be errors.  [This option is specific
2334           to the i386 PE targeted port of the linker]
2335
2336       --leading-underscore
2337       --no-leading-underscore
2338           For most targets default symbol-prefix is an underscore and is
2339           defined in target's description. By this option it is possible to
2340           disable/enable the default underscore symbol-prefix.
2341
2342       --export-all-symbols
2343           If given, all global symbols in the objects used to build a DLL
2344           will be exported by the DLL.  Note that this is the default if
2345           there otherwise wouldn't be any exported symbols.  When symbols are
2346           explicitly exported via DEF files or implicitly exported via
2347           function attributes, the default is to not export anything else
2348           unless this option is given.  Note that the symbols "DllMain@12",
2349           "DllEntryPoint@0", "DllMainCRTStartup@12", and "impure_ptr" will
2350           not be automatically exported.  Also, symbols imported from other
2351           DLLs will not be re-exported, nor will symbols specifying the DLL's
2352           internal layout such as those beginning with "_head_" or ending
2353           with "_iname".  In addition, no symbols from "libgcc", "libstd++",
2354           "libmingw32", or "crtX.o" will be exported.  Symbols whose names
2355           begin with "__rtti_" or "__builtin_" will not be exported, to help
2356           with C++ DLLs.  Finally, there is an extensive list of cygwin-
2357           private symbols that are not exported (obviously, this applies on
2358           when building DLLs for cygwin targets).  These cygwin-excludes are:
2359           "_cygwin_dll_entry@12", "_cygwin_crt0_common@8",
2360           "_cygwin_noncygwin_dll_entry@12", "_fmode", "_impure_ptr",
2361           "cygwin_attach_dll", "cygwin_premain0", "cygwin_premain1",
2362           "cygwin_premain2", "cygwin_premain3", and "environ".  [This option
2363           is specific to the i386 PE targeted port of the linker]
2364
2365       --exclude-symbols symbol,symbol,...
2366           Specifies a list of symbols which should not be automatically
2367           exported.  The symbol names may be delimited by commas or colons.
2368           [This option is specific to the i386 PE targeted port of the
2369           linker]
2370
2371       --exclude-all-symbols
2372           Specifies no symbols should be automatically exported.  [This
2373           option is specific to the i386 PE targeted port of the linker]
2374
2375       --file-alignment
2376           Specify the file alignment.  Sections in the file will always begin
2377           at file offsets which are multiples of this number.  This defaults
2378           to 512.  [This option is specific to the i386 PE targeted port of
2379           the linker]
2380
2381       --heap reserve
2382       --heap reserve,commit
2383           Specify the number of bytes of memory to reserve (and optionally
2384           commit) to be used as heap for this program.  The default is 1MB
2385           reserved, 4K committed.  [This option is specific to the i386 PE
2386           targeted port of the linker]
2387
2388       --image-base value
2389           Use value as the base address of your program or dll.  This is the
2390           lowest memory location that will be used when your program or dll
2391           is loaded.  To reduce the need to relocate and improve performance
2392           of your dlls, each should have a unique base address and not
2393           overlap any other dlls.  The default is 0x400000 for executables,
2394           and 0x10000000 for dlls.  [This option is specific to the i386 PE
2395           targeted port of the linker]
2396
2397       --kill-at
2398           If given, the stdcall suffixes (@nn) will be stripped from symbols
2399           before they are exported.  [This option is specific to the i386 PE
2400           targeted port of the linker]
2401
2402       --large-address-aware
2403           If given, the appropriate bit in the "Characteristics" field of the
2404           COFF header is set to indicate that this executable supports
2405           virtual addresses greater than 2 gigabytes.  This should be used in
2406           conjunction with the /3GB or /USERVA=value megabytes switch in the
2407           "[operating systems]" section of the BOOT.INI.  Otherwise, this bit
2408           has no effect.  [This option is specific to PE targeted ports of
2409           the linker]
2410
2411       --disable-large-address-aware
2412           Reverts the effect of a previous --large-address-aware option.
2413           This is useful if --large-address-aware is always set by the
2414           compiler driver (e.g. Cygwin gcc) and the executable does not
2415           support virtual addresses greater than 2 gigabytes.  [This option
2416           is specific to PE targeted ports of the linker]
2417
2418       --major-image-version value
2419           Sets the major number of the "image version".  Defaults to 1.
2420           [This option is specific to the i386 PE targeted port of the
2421           linker]
2422
2423       --major-os-version value
2424           Sets the major number of the "os version".  Defaults to 4.  [This
2425           option is specific to the i386 PE targeted port of the linker]
2426
2427       --major-subsystem-version value
2428           Sets the major number of the "subsystem version".  Defaults to 4.
2429           [This option is specific to the i386 PE targeted port of the
2430           linker]
2431
2432       --minor-image-version value
2433           Sets the minor number of the "image version".  Defaults to 0.
2434           [This option is specific to the i386 PE targeted port of the
2435           linker]
2436
2437       --minor-os-version value
2438           Sets the minor number of the "os version".  Defaults to 0.  [This
2439           option is specific to the i386 PE targeted port of the linker]
2440
2441       --minor-subsystem-version value
2442           Sets the minor number of the "subsystem version".  Defaults to 0.
2443           [This option is specific to the i386 PE targeted port of the
2444           linker]
2445
2446       --output-def file
2447           The linker will create the file file which will contain a DEF file
2448           corresponding to the DLL the linker is generating.  This DEF file
2449           (which should be called "*.def") may be used to create an import
2450           library with "dlltool" or may be used as a reference to
2451           automatically or implicitly exported symbols.  [This option is
2452           specific to the i386 PE targeted port of the linker]
2453
2454       --enable-auto-image-base
2455       --enable-auto-image-base=value
2456           Automatically choose the image base for DLLs, optionally starting
2457           with base value, unless one is specified using the "--image-base"
2458           argument.  By using a hash generated from the dllname to create
2459           unique image bases for each DLL, in-memory collisions and
2460           relocations which can delay program execution are avoided.  [This
2461           option is specific to the i386 PE targeted port of the linker]
2462
2463       --disable-auto-image-base
2464           Do not automatically generate a unique image base.  If there is no
2465           user-specified image base ("--image-base") then use the platform
2466           default.  [This option is specific to the i386 PE targeted port of
2467           the linker]
2468
2469       --dll-search-prefix string
2470           When linking dynamically to a dll without an import library, search
2471           for "<string><basename>.dll" in preference to "lib<basename>.dll".
2472           This behaviour allows easy distinction between DLLs built for the
2473           various "subplatforms": native, cygwin, uwin, pw, etc.  For
2474           instance, cygwin DLLs typically use "--dll-search-prefix=cyg".
2475           [This option is specific to the i386 PE targeted port of the
2476           linker]
2477
2478       --enable-auto-import
2479           Do sophisticated linking of "_symbol" to "__imp__symbol" for DATA
2480           imports from DLLs, thus making it possible to bypass the dllimport
2481           mechanism on the user side and to reference unmangled symbol names.
2482           [This option is specific to the i386 PE targeted port of the
2483           linker]
2484
2485           The following remarks pertain to the original implementation of the
2486           feature and are obsolete nowadays for Cygwin and MinGW targets.
2487
2488           Note: Use of the 'auto-import' extension will cause the text
2489           section of the image file to be made writable. This does not
2490           conform to the PE-COFF format specification published by Microsoft.
2491
2492           Note - use of the 'auto-import' extension will also cause read only
2493           data which would normally be placed into the .rdata section to be
2494           placed into the .data section instead.  This is in order to work
2495           around a problem with consts that is described here:
2496           http://www.cygwin.com/ml/cygwin/2004-09/msg01101.html
2497
2498           Using 'auto-import' generally will 'just work' -- but sometimes you
2499           may see this message:
2500
2501           "variable '<var>' can't be auto-imported. Please read the
2502           documentation for ld's "--enable-auto-import" for details."
2503
2504           This message occurs when some (sub)expression accesses an address
2505           ultimately given by the sum of two constants (Win32 import tables
2506           only allow one).  Instances where this may occur include accesses
2507           to member fields of struct variables imported from a DLL, as well
2508           as using a constant index into an array variable imported from a
2509           DLL.  Any multiword variable (arrays, structs, long long, etc) may
2510           trigger this error condition.  However, regardless of the exact
2511           data type of the offending exported variable, ld will always detect
2512           it, issue the warning, and exit.
2513
2514           There are several ways to address this difficulty, regardless of
2515           the data type of the exported variable:
2516
2517           One way is to use --enable-runtime-pseudo-reloc switch. This leaves
2518           the task of adjusting references in your client code for runtime
2519           environment, so this method works only when runtime environment
2520           supports this feature.
2521
2522           A second solution is to force one of the 'constants' to be a
2523           variable -- that is, unknown and un-optimizable at compile time.
2524           For arrays, there are two possibilities: a) make the indexee (the
2525           array's address) a variable, or b) make the 'constant' index a
2526           variable.  Thus:
2527
2528                   extern type extern_array[];
2529                   extern_array[1] -->
2530                      { volatile type *t=extern_array; t[1] }
2531
2532           or
2533
2534                   extern type extern_array[];
2535                   extern_array[1] -->
2536                      { volatile int t=1; extern_array[t] }
2537
2538           For structs (and most other multiword data types) the only option
2539           is to make the struct itself (or the long long, or the ...)
2540           variable:
2541
2542                   extern struct s extern_struct;
2543                   extern_struct.field -->
2544                      { volatile struct s *t=&extern_struct; t->field }
2545
2546           or
2547
2548                   extern long long extern_ll;
2549                   extern_ll -->
2550                     { volatile long long * local_ll=&extern_ll; *local_ll }
2551
2552           A third method of dealing with this difficulty is to abandon
2553           'auto-import' for the offending symbol and mark it with
2554           "__declspec(dllimport)".  However, in practice that requires using
2555           compile-time #defines to indicate whether you are building a DLL,
2556           building client code that will link to the DLL, or merely
2557           building/linking to a static library.   In making the choice
2558           between the various methods of resolving the 'direct address with
2559           constant offset' problem, you should consider typical real-world
2560           usage:
2561
2562           Original:
2563
2564                   --foo.h
2565                   extern int arr[];
2566                   --foo.c
2567                   #include "foo.h"
2568                   void main(int argc, char **argv){
2569                     printf("%d\n",arr[1]);
2570                   }
2571
2572           Solution 1:
2573
2574                   --foo.h
2575                   extern int arr[];
2576                   --foo.c
2577                   #include "foo.h"
2578                   void main(int argc, char **argv){
2579                     /* This workaround is for win32 and cygwin; do not "optimize" */
2580                     volatile int *parr = arr;
2581                     printf("%d\n",parr[1]);
2582                   }
2583
2584           Solution 2:
2585
2586                   --foo.h
2587                   /* Note: auto-export is assumed (no __declspec(dllexport)) */
2588                   #if (defined(_WIN32) || defined(__CYGWIN__)) && \
2589                     !(defined(FOO_BUILD_DLL) || defined(FOO_STATIC))
2590                   #define FOO_IMPORT __declspec(dllimport)
2591                   #else
2592                   #define FOO_IMPORT
2593                   #endif
2594                   extern FOO_IMPORT int arr[];
2595                   --foo.c
2596                   #include "foo.h"
2597                   void main(int argc, char **argv){
2598                     printf("%d\n",arr[1]);
2599                   }
2600
2601           A fourth way to avoid this problem is to re-code your library to
2602           use a functional interface rather than a data interface for the
2603           offending variables (e.g. set_foo() and get_foo() accessor
2604           functions).
2605
2606       --disable-auto-import
2607           Do not attempt to do sophisticated linking of "_symbol" to
2608           "__imp__symbol" for DATA imports from DLLs.  [This option is
2609           specific to the i386 PE targeted port of the linker]
2610
2611       --enable-runtime-pseudo-reloc
2612           If your code contains expressions described in --enable-auto-import
2613           section, that is, DATA imports from DLL with non-zero offset, this
2614           switch will create a vector of 'runtime pseudo relocations' which
2615           can be used by runtime environment to adjust references to such
2616           data in your client code.  [This option is specific to the i386 PE
2617           targeted port of the linker]
2618
2619       --disable-runtime-pseudo-reloc
2620           Do not create pseudo relocations for non-zero offset DATA imports
2621           from DLLs.  [This option is specific to the i386 PE targeted port
2622           of the linker]
2623
2624       --enable-extra-pe-debug
2625           Show additional debug info related to auto-import symbol thunking.
2626           [This option is specific to the i386 PE targeted port of the
2627           linker]
2628
2629       --section-alignment
2630           Sets the section alignment.  Sections in memory will always begin
2631           at addresses which are a multiple of this number.  Defaults to
2632           0x1000.  [This option is specific to the i386 PE targeted port of
2633           the linker]
2634
2635       --stack reserve
2636       --stack reserve,commit
2637           Specify the number of bytes of memory to reserve (and optionally
2638           commit) to be used as stack for this program.  The default is 2MB
2639           reserved, 4K committed.  [This option is specific to the i386 PE
2640           targeted port of the linker]
2641
2642       --subsystem which
2643       --subsystem which:major
2644       --subsystem which:major.minor
2645           Specifies the subsystem under which your program will execute.  The
2646           legal values for which are "native", "windows", "console", "posix",
2647           and "xbox".  You may optionally set the subsystem version also.
2648           Numeric values are also accepted for which.  [This option is
2649           specific to the i386 PE targeted port of the linker]
2650
2651           The following options set flags in the "DllCharacteristics" field
2652           of the PE file header: [These options are specific to PE targeted
2653           ports of the linker]
2654
2655       --high-entropy-va
2656       --disable-high-entropy-va
2657           Image is compatible with 64-bit address space layout randomization
2658           (ASLR).  This option is enabled by default for 64-bit PE images.
2659
2660           This option also implies --dynamicbase and --enable-reloc-section.
2661
2662       --dynamicbase
2663       --disable-dynamicbase
2664           The image base address may be relocated using address space layout
2665           randomization (ASLR).  This feature was introduced with MS Windows
2666           Vista for i386 PE targets.  This option is enabled by default but
2667           can be disabled via the --disable-dynamicbase option.  This option
2668           also implies --enable-reloc-section.
2669
2670       --forceinteg
2671       --disable-forceinteg
2672           Code integrity checks are enforced.  This option is disabled by
2673           default.
2674
2675       --nxcompat
2676       --disable-nxcompat
2677           The image is compatible with the Data Execution Prevention.  This
2678           feature was introduced with MS Windows XP SP2 for i386 PE targets.
2679           The option is enabled by default.
2680
2681       --no-isolation
2682       --disable-no-isolation
2683           Although the image understands isolation, do not isolate the image.
2684           This option is disabled by default.
2685
2686       --no-seh
2687       --disable-no-seh
2688           The image does not use SEH. No SE handler may be called from this
2689           image.  This option is disabled by default.
2690
2691       --no-bind
2692       --disable-no-bind
2693           Do not bind this image.  This option is disabled by default.
2694
2695       --wdmdriver
2696       --disable-wdmdriver
2697           The driver uses the MS Windows Driver Model.  This option is
2698           disabled by default.
2699
2700       --tsaware
2701       --disable-tsaware
2702           The image is Terminal Server aware.  This option is disabled by
2703           default.
2704
2705       --insert-timestamp
2706       --no-insert-timestamp
2707           Insert a real timestamp into the image.  This is the default
2708           behaviour as it matches legacy code and it means that the image
2709           will work with other, proprietary tools.  The problem with this
2710           default is that it will result in slightly different images being
2711           produced each time the same sources are linked.  The option
2712           --no-insert-timestamp can be used to insert a zero value for the
2713           timestamp, this ensuring that binaries produced from identical
2714           sources will compare identically.
2715
2716       --enable-reloc-section
2717       --disable-reloc-section
2718           Create the base relocation table, which is necessary if the image
2719           is loaded at a different image base than specified in the PE
2720           header.  This option is enabled by default.
2721
2722       The C6X uClinux target uses a binary format called DSBT to support
2723       shared libraries.  Each shared library in the system needs to have a
2724       unique index; all executables use an index of 0.
2725
2726       --dsbt-size size
2727           This option sets the number of entries in the DSBT of the current
2728           executable or shared library to size.  The default is to create a
2729           table with 64 entries.
2730
2731       --dsbt-index index
2732           This option sets the DSBT index of the current executable or shared
2733           library to index.  The default is 0, which is appropriate for
2734           generating executables.  If a shared library is generated with a
2735           DSBT index of 0, the "R_C6000_DSBT_INDEX" relocs are copied into
2736           the output file.
2737
2738           The --no-merge-exidx-entries switch disables the merging of
2739           adjacent exidx entries in frame unwind info.
2740
2741       --branch-stub
2742           This option enables linker branch relaxation by inserting branch
2743           stub sections when needed to extend the range of branches.  This
2744           option is usually not required since C-SKY supports branch and call
2745           instructions that can access the full memory range and branch
2746           relaxation is normally handled by the compiler or assembler.
2747
2748       --stub-group-size=N
2749           This option allows finer control of linker branch stub creation.
2750           It sets the maximum size of a group of input sections that can be
2751           handled by one stub section.  A negative value of N locates stub
2752           sections after their branches, while a positive value allows stub
2753           sections to appear either before or after the branches.  Values of
2754           1 or -1 indicate that the linker should choose suitable defaults.
2755
2756       The 68HC11 and 68HC12 linkers support specific options to control the
2757       memory bank switching mapping and trampoline code generation.
2758
2759       --no-trampoline
2760           This option disables the generation of trampoline. By default a
2761           trampoline is generated for each far function which is called using
2762           a "jsr" instruction (this happens when a pointer to a far function
2763           is taken).
2764
2765       --bank-window name
2766           This option indicates to the linker the name of the memory region
2767           in the MEMORY specification that describes the memory bank window.
2768           The definition of such region is then used by the linker to compute
2769           paging and addresses within the memory window.
2770
2771       The following options are supported to control handling of GOT
2772       generation when linking for 68K targets.
2773
2774       --got=type
2775           This option tells the linker which GOT generation scheme to use.
2776           type should be one of single, negative, multigot or target.  For
2777           more information refer to the Info entry for ld.
2778
2779       The following options are supported to control microMIPS instruction
2780       generation and branch relocation checks for ISA mode transitions when
2781       linking for MIPS targets.
2782
2783       --insn32
2784       --no-insn32
2785           These options control the choice of microMIPS instructions used in
2786           code generated by the linker, such as that in the PLT or lazy
2787           binding stubs, or in relaxation.  If --insn32 is used, then the
2788           linker only uses 32-bit instruction encodings.  By default or if
2789           --no-insn32 is used, all instruction encodings are used, including
2790           16-bit ones where possible.
2791
2792       --ignore-branch-isa
2793       --no-ignore-branch-isa
2794           These options control branch relocation checks for invalid ISA mode
2795           transitions.  If --ignore-branch-isa is used, then the linker
2796           accepts any branch relocations and any ISA mode transition required
2797           is lost in relocation calculation, except for some cases of "BAL"
2798           instructions which meet relaxation conditions and are converted to
2799           equivalent "JALX" instructions as the associated relocation is
2800           calculated.  By default or if --no-ignore-branch-isa is used a
2801           check is made causing the loss of an ISA mode transition to produce
2802           an error.
2803
2804       --compact-branches
2805       --no-compact-branches
2806           These options control the generation of compact instructions by the
2807           linker in the PLT entries for MIPS R6.
2808
2809       For the pdp11-aout target, three variants of the output format can be
2810       produced as selected by the following options.  The default variant for
2811       pdp11-aout is the --omagic option, whereas for other targets --nmagic
2812       is the default.  The --imagic option is defined only for the pdp11-aout
2813       target, while the others are described here as they apply to the
2814       pdp11-aout target.
2815
2816       -N
2817       --omagic
2818           Mark the output as "OMAGIC" (0407) in the a.out header to indicate
2819           that the text segment is not to be write-protected and shared.
2820           Since the text and data sections are both readable and writable,
2821           the data section is allocated immediately contiguous after the text
2822           segment.  This is the oldest format for PDP11 executable programs
2823           and is the default for ld on PDP11 Unix systems from the beginning
2824           through 2.11BSD.
2825
2826       -n
2827       --nmagic
2828           Mark the output as "NMAGIC" (0410) in the a.out header to indicate
2829           that when the output file is executed, the text portion will be
2830           read-only and shareable among all processes executing the same
2831           file.  This involves moving the data areas up to the first possible
2832           8K byte page boundary following the end of the text.  This option
2833           creates a pure executable format.
2834
2835       -z
2836       --imagic
2837           Mark the output as "IMAGIC" (0411) in the a.out header to indicate
2838           that when the output file is executed, the program text and data
2839           areas will be loaded into separate address spaces using the split
2840           instruction and data space feature of the memory management unit in
2841           larger models of the PDP11.  This doubles the address space
2842           available to the program.  The text segment is again pure, write-
2843           protected, and shareable.  The only difference in the output format
2844           between this option and the others, besides the magic number, is
2845           that both the text and data sections start at location 0.  The -z
2846           option selected this format in 2.11BSD.  This option creates a
2847           separate executable format.
2848
2849       --no-omagic
2850           Equivalent to --nmagic for pdp11-aout.
2851

ENVIRONMENT

2853       You can change the behaviour of ld with the environment variables
2854       "GNUTARGET", "LDEMULATION" and "COLLECT_NO_DEMANGLE".
2855
2856       "GNUTARGET" determines the input-file object format if you don't use -b
2857       (or its synonym --format).  Its value should be one of the BFD names
2858       for an input format.  If there is no "GNUTARGET" in the environment, ld
2859       uses the natural format of the target. If "GNUTARGET" is set to
2860       "default" then BFD attempts to discover the input format by examining
2861       binary input files; this method often succeeds, but there are potential
2862       ambiguities, since there is no method of ensuring that the magic number
2863       used to specify object-file formats is unique.  However, the
2864       configuration procedure for BFD on each system places the conventional
2865       format for that system first in the search-list, so ambiguities are
2866       resolved in favor of convention.
2867
2868       "LDEMULATION" determines the default emulation if you don't use the -m
2869       option.  The emulation can affect various aspects of linker behaviour,
2870       particularly the default linker script.  You can list the available
2871       emulations with the --verbose or -V options.  If the -m option is not
2872       used, and the "LDEMULATION" environment variable is not defined, the
2873       default emulation depends upon how the linker was configured.
2874
2875       Normally, the linker will default to demangling symbols.  However, if
2876       "COLLECT_NO_DEMANGLE" is set in the environment, then it will default
2877       to not demangling symbols.  This environment variable is used in a
2878       similar fashion by the "gcc" linker wrapper program.  The default may
2879       be overridden by the --demangle and --no-demangle options.
2880

SEE ALSO

2882       ar(1), nm(1), objcopy(1), objdump(1), readelf(1) and the Info entries
2883       for binutils and ld.
2884
2886       Copyright (c) 1991-2022 Free Software Foundation, Inc.
2887
2888       Permission is granted to copy, distribute and/or modify this document
2889       under the terms of the GNU Free Documentation License, Version 1.3 or
2890       any later version published by the Free Software Foundation; with no
2891       Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
2892       Texts.  A copy of the license is included in the section entitled "GNU
2893       Free Documentation License".
2894
2895
2896
2897binutils-2.38                     2022-12-30                             LD(1)
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