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 the using the file
388           name 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           initfirst
883               This option is only meaningful when building a shared object.
884               It marks the object so that its runtime initialization will
885               occur before the runtime initialization of any other objects
886               brought into the process at the same time.  Similarly the
887               runtime finalization of the object will occur after the runtime
888               finalization of any other objects.
889
890           interpose
891               Specify that the dynamic loader should modify its symbol search
892               order so that symbols in this shared library interpose all
893               other shared libraries not so marked.
894
895           unique
896           nounique
897               When generating a shared library or other dynamically loadable
898               ELF object mark it as one that should (by default) only ever be
899               loaded once, and only in the main namespace (when using
900               "dlmopen"). This is primarily used to mark fundamental
901               libraries such as libc, libpthread et al which do not usually
902               function correctly unless they are the sole instances of
903               themselves. This behaviour can be overridden by the "dlmopen"
904               caller and does not apply to certain loading mechanisms (such
905               as audit libraries).
906
907           lam-u48
908               Generate GNU_PROPERTY_X86_FEATURE_1_LAM_U48 in
909               .note.gnu.property section to indicate compatibility with Intel
910               LAM_U48.  Supported for Linux/x86_64.
911
912           lam-u57
913               Generate GNU_PROPERTY_X86_FEATURE_1_LAM_U57 in
914               .note.gnu.property section to indicate compatibility with Intel
915               LAM_U57.  Supported for Linux/x86_64.
916
917           lam-u48-report=none
918           lam-u48-report=warning
919           lam-u48-report=error
920               Specify how to report the missing
921               GNU_PROPERTY_X86_FEATURE_1_LAM_U48 property in input
922               .note.gnu.property section.  lam-u48-report=none, which is the
923               default, will make the linker not report missing properties in
924               input files.  lam-u48-report=warning will make the linker issue
925               a warning for missing properties in input files.
926               lam-u48-report=error will make the linker issue an error for
927               missing properties in input files.  Supported for Linux/x86_64.
928
929           lam-u57-report=none
930           lam-u57-report=warning
931           lam-u57-report=error
932               Specify how to report the missing
933               GNU_PROPERTY_X86_FEATURE_1_LAM_U57 property in input
934               .note.gnu.property section.  lam-u57-report=none, which is the
935               default, will make the linker not report missing properties in
936               input files.  lam-u57-report=warning will make the linker issue
937               a warning for missing properties in input files.
938               lam-u57-report=error will make the linker issue an error for
939               missing properties in input files.  Supported for Linux/x86_64.
940
941           lam-report=none
942           lam-report=warning
943           lam-report=error
944               Specify how to report the missing
945               GNU_PROPERTY_X86_FEATURE_1_LAM_U48 and
946               GNU_PROPERTY_X86_FEATURE_1_LAM_U57 properties in input
947               .note.gnu.property section.  lam-report=none, which is the
948               default, will make the linker not report missing properties in
949               input files.  lam-report=warning will make the linker issue a
950               warning for missing properties in input files.
951               lam-report=error will make the linker issue an error for
952               missing properties in input files.  Supported for Linux/x86_64.
953
954           lazy
955               When generating an executable or shared library, mark it to
956               tell the dynamic linker to defer function call resolution to
957               the point when the function is called (lazy binding), rather
958               than at load time.  Lazy binding is the default.
959
960           loadfltr
961               Specify that the object's filters be processed immediately at
962               runtime.
963
964           max-page-size=value
965               Set the maximum memory page size supported to value.
966
967           muldefs
968               Allow multiple definitions.
969
970           nocopyreloc
971               Disable linker generated .dynbss variables used in place of
972               variables defined in shared libraries.  May result in dynamic
973               text relocations.
974
975           nodefaultlib
976               Specify that the dynamic loader search for dependencies of this
977               object should ignore any default library search paths.
978
979           nodelete
980               Specify that the object shouldn't be unloaded at runtime.
981
982           nodlopen
983               Specify that the object is not available to "dlopen".
984
985           nodump
986               Specify that the object can not be dumped by "dldump".
987
988           noexecstack
989               Marks the object as not requiring executable stack.
990
991           noextern-protected-data
992               Don't treat protected data symbols as external when building a
993               shared library.  This option overrides the linker backend
994               default.  It can be used to work around incorrect relocations
995               against protected data symbols generated by compiler.  Updates
996               on protected data symbols by another module aren't visible to
997               the resulting shared library.  Supported for i386 and x86-64.
998
999           noreloc-overflow
1000               Disable relocation overflow check.  This can be used to disable
1001               relocation overflow check if there will be no dynamic
1002               relocation overflow at run-time.  Supported for x86_64.
1003
1004           now When generating an executable or shared library, mark it to
1005               tell the dynamic linker to resolve all symbols when the program
1006               is started, or when the shared library is loaded by dlopen,
1007               instead of deferring function call resolution to the point when
1008               the function is first called.
1009
1010           origin
1011               Specify that the object requires $ORIGIN handling in paths.
1012
1013           relro
1014           norelro
1015               Create an ELF "PT_GNU_RELRO" segment header in the object.
1016               This specifies a memory segment that should be made read-only
1017               after relocation, if supported.  Specifying common-page-size
1018               smaller than the system page size will render this protection
1019               ineffective.  Don't create an ELF "PT_GNU_RELRO" segment if
1020               norelro.
1021
1022           report-relative-reloc
1023               Report dynamic relative relocations generated by linker.
1024               Supported for Linux/i386 and Linux/x86_64.
1025
1026           separate-code
1027           noseparate-code
1028               Create separate code "PT_LOAD" segment header in the object.
1029               This specifies a memory segment that should contain only
1030               instructions and must be in wholly disjoint pages from any
1031               other data.  Don't create separate code "PT_LOAD" segment if
1032               noseparate-code is used.
1033
1034           shstk
1035               Generate GNU_PROPERTY_X86_FEATURE_1_SHSTK in .note.gnu.property
1036               section to indicate compatibility with Intel Shadow Stack.
1037               Supported for Linux/i386 and Linux/x86_64.
1038
1039           stack-size=value
1040               Specify a stack size for an ELF "PT_GNU_STACK" segment.
1041               Specifying zero will override any default non-zero sized
1042               "PT_GNU_STACK" segment creation.
1043
1044           start-stop-gc
1045           nostart-stop-gc
1046               When --gc-sections is in effect, a reference from a retained
1047               section to "__start_SECNAME" or "__stop_SECNAME" causes all
1048               input sections named "SECNAME" to also be retained, if
1049               "SECNAME" is representable as a C identifier and either
1050               "__start_SECNAME" or "__stop_SECNAME" is synthesized by the
1051               linker.  -z start-stop-gc disables this effect, allowing
1052               sections to be garbage collected as if the special synthesized
1053               symbols were not defined.  -z start-stop-gc has no effect on a
1054               definition of "__start_SECNAME" or "__stop_SECNAME" in an
1055               object file or linker script.  Such a definition will prevent
1056               the linker providing a synthesized "__start_SECNAME" or
1057               "__stop_SECNAME" respectively, and therefore the special
1058               treatment by garbage collection for those references.
1059
1060           start-stop-visibility=value
1061               Specify the ELF symbol visibility for synthesized
1062               "__start_SECNAME" and "__stop_SECNAME" symbols.  value must be
1063               exactly default, internal, hidden, or protected.  If no -z
1064               start-stop-visibility option is given, protected is used for
1065               compatibility with historical practice.  However, it's highly
1066               recommended to use -z start-stop-visibility=hidden in new
1067               programs and shared libraries so that these symbols are not
1068               exported between shared objects, which is not usually what's
1069               intended.
1070
1071           text
1072           notext
1073           textoff
1074               Report an error if DT_TEXTREL is set, i.e., if the position-
1075               independent or shared object has dynamic relocations in read-
1076               only sections.  Don't report an error if notext or textoff.
1077
1078           undefs
1079               Do not report unresolved symbol references from regular object
1080               files, either when creating an executable, or when creating a
1081               shared library.  This option is the inverse of -z defs.
1082
1083           unique-symbol
1084           nounique-symbol
1085               Avoid duplicated local symbol names in the symbol string table.
1086               Append "."number"" to duplicated local symbol names if unique-
1087               symbol is used.  nounique-symbol is the default.
1088
1089           x86-64-baseline
1090           x86-64-v2
1091           x86-64-v3
1092           x86-64-v4
1093               Specify the x86-64 ISA level needed in .note.gnu.property
1094               section.  x86-64-baseline generates
1095               "GNU_PROPERTY_X86_ISA_1_BASELINE".  x86-64-v2 generates
1096               "GNU_PROPERTY_X86_ISA_1_V2".  x86-64-v3 generates
1097               "GNU_PROPERTY_X86_ISA_1_V3".  x86-64-v4 generates
1098               "GNU_PROPERTY_X86_ISA_1_V4".  Supported for Linux/i386 and
1099               Linux/x86_64.
1100
1101           Other keywords are ignored for Solaris compatibility.
1102
1103       -( archives -)
1104       --start-group archives --end-group
1105           The archives should be a list of archive files.  They may be either
1106           explicit file names, or -l options.
1107
1108           The specified archives are searched repeatedly until no new
1109           undefined references are created.  Normally, an archive is searched
1110           only once in the order that it is specified on the command line.
1111           If a symbol in that archive is needed to resolve an undefined
1112           symbol referred to by an object in an archive that appears later on
1113           the command line, the linker would not be able to resolve that
1114           reference.  By grouping the archives, they will all be searched
1115           repeatedly until all possible references are resolved.
1116
1117           Using this option has a significant performance cost.  It is best
1118           to use it only when there are unavoidable circular references
1119           between two or more archives.
1120
1121       --accept-unknown-input-arch
1122       --no-accept-unknown-input-arch
1123           Tells the linker to accept input files whose architecture cannot be
1124           recognised.  The assumption is that the user knows what they are
1125           doing and deliberately wants to link in these unknown input files.
1126           This was the default behaviour of the linker, before release 2.14.
1127           The default behaviour from release 2.14 onwards is to reject such
1128           input files, and so the --accept-unknown-input-arch option has been
1129           added to restore the old behaviour.
1130
1131       --as-needed
1132       --no-as-needed
1133           This option affects ELF DT_NEEDED tags for dynamic libraries
1134           mentioned on the command line after the --as-needed option.
1135           Normally the linker will add a DT_NEEDED tag for each dynamic
1136           library mentioned on the command line, regardless of whether the
1137           library is actually needed or not.  --as-needed causes a DT_NEEDED
1138           tag to only be emitted for a library that at that point in the link
1139           satisfies a non-weak undefined symbol reference from a regular
1140           object file or, if the library is not found in the DT_NEEDED lists
1141           of other needed libraries, a non-weak undefined symbol reference
1142           from another needed dynamic library.  Object files or libraries
1143           appearing on the command line after the library in question do not
1144           affect whether the library is seen as needed.  This is similar to
1145           the rules for extraction of object files from archives.
1146           --no-as-needed restores the default behaviour.
1147
1148           Note: On Linux based systems the --as-needed option also has an
1149           affect on the behaviour of the --rpath and --rpath-link options.
1150           See the description of --rpath-link for more details.
1151
1152       --add-needed
1153       --no-add-needed
1154           These two options have been deprecated because of the similarity of
1155           their names to the --as-needed and --no-as-needed options.  They
1156           have been replaced by --copy-dt-needed-entries and
1157           --no-copy-dt-needed-entries.
1158
1159       -assert keyword
1160           This option is ignored for SunOS compatibility.
1161
1162       -Bdynamic
1163       -dy
1164       -call_shared
1165           Link against dynamic libraries.  This is only meaningful on
1166           platforms for which shared libraries are supported.  This option is
1167           normally the default on such platforms.  The different variants of
1168           this option are for compatibility with various systems.  You may
1169           use this option multiple times on the command line: it affects
1170           library searching for -l options which follow it.
1171
1172       -Bgroup
1173           Set the "DF_1_GROUP" flag in the "DT_FLAGS_1" entry in the dynamic
1174           section.  This causes the runtime linker to handle lookups in this
1175           object and its dependencies to be performed only inside the group.
1176           --unresolved-symbols=report-all is implied.  This option is only
1177           meaningful on ELF platforms which support shared libraries.
1178
1179       -Bstatic
1180       -dn
1181       -non_shared
1182       -static
1183           Do not link against shared libraries.  This is only meaningful on
1184           platforms for which shared libraries are supported.  The different
1185           variants of this option are for compatibility with various systems.
1186           You may use this option multiple times on the command line: it
1187           affects library searching for -l options which follow it.  This
1188           option also implies --unresolved-symbols=report-all.  This option
1189           can be used with -shared.  Doing so means that a shared library is
1190           being created but that all of the library's external references
1191           must be resolved by pulling in entries from static libraries.
1192
1193       -Bsymbolic
1194           When creating a shared library, bind references to global symbols
1195           to the definition within the shared library, if any.  Normally, it
1196           is possible for a program linked against a shared library to
1197           override the definition within the shared library.  This option is
1198           only meaningful on ELF platforms which support shared libraries.
1199
1200       -Bsymbolic-functions
1201           When creating a shared library, bind references to global function
1202           symbols to the definition within the shared library, if any.  This
1203           option is only meaningful on ELF platforms which support shared
1204           libraries.
1205
1206       -Bno-symbolic
1207           This option can cancel previously specified -Bsymbolic and
1208           -Bsymbolic-functions.
1209
1210       --dynamic-list=dynamic-list-file
1211           Specify the name of a dynamic list file to the linker.  This is
1212           typically used when creating shared libraries to specify a list of
1213           global symbols whose references shouldn't be bound to the
1214           definition within the shared library, or creating dynamically
1215           linked executables to specify a list of symbols which should be
1216           added to the symbol table in the executable.  This option is only
1217           meaningful on ELF platforms which support shared libraries.
1218
1219           The format of the dynamic list is the same as the version node
1220           without scope and node name.  See VERSION for more information.
1221
1222       --dynamic-list-data
1223           Include all global data symbols to the dynamic list.
1224
1225       --dynamic-list-cpp-new
1226           Provide the builtin dynamic list for C++ operator new and delete.
1227           It is mainly useful for building shared libstdc++.
1228
1229       --dynamic-list-cpp-typeinfo
1230           Provide the builtin dynamic list for C++ runtime type
1231           identification.
1232
1233       --check-sections
1234       --no-check-sections
1235           Asks the linker not to check section addresses after they have been
1236           assigned to see if there are any overlaps.  Normally the linker
1237           will perform this check, and if it finds any overlaps it will
1238           produce suitable error messages.  The linker does know about, and
1239           does make allowances for sections in overlays.  The default
1240           behaviour can be restored by using the command-line switch
1241           --check-sections.  Section overlap is not usually checked for
1242           relocatable links.  You can force checking in that case by using
1243           the --check-sections option.
1244
1245       --copy-dt-needed-entries
1246       --no-copy-dt-needed-entries
1247           This option affects the treatment of dynamic libraries referred to
1248           by DT_NEEDED tags inside ELF dynamic libraries mentioned on the
1249           command line.  Normally the linker won't add a DT_NEEDED tag to the
1250           output binary for each library mentioned in a DT_NEEDED tag in an
1251           input dynamic library.  With --copy-dt-needed-entries specified on
1252           the command line however any dynamic libraries that follow it will
1253           have their DT_NEEDED entries added.  The default behaviour can be
1254           restored with --no-copy-dt-needed-entries.
1255
1256           This option also has an effect on the resolution of symbols in
1257           dynamic libraries.  With --copy-dt-needed-entries dynamic libraries
1258           mentioned on the command line will be recursively searched,
1259           following their DT_NEEDED tags to other libraries, in order to
1260           resolve symbols required by the output binary.  With the default
1261           setting however the searching of dynamic libraries that follow it
1262           will stop with the dynamic library itself.  No DT_NEEDED links will
1263           be traversed to resolve symbols.
1264
1265       --cref
1266           Output a cross reference table.  If a linker map file is being
1267           generated, the cross reference table is printed to the map file.
1268           Otherwise, it is printed on the standard output.
1269
1270           The format of the table is intentionally simple, so that it may be
1271           easily processed by a script if necessary.  The symbols are printed
1272           out, sorted by name.  For each symbol, a list of file names is
1273           given.  If the symbol is defined, the first file listed is the
1274           location of the definition.  If the symbol is defined as a common
1275           value then any files where this happens appear next.  Finally any
1276           files that reference the symbol are listed.
1277
1278       --ctf-variables
1279       --no-ctf-variables
1280           The CTF debuginfo format supports a section which encodes the names
1281           and types of variables found in the program which do not appear in
1282           any symbol table. These variables clearly cannot be looked up by
1283           address by conventional debuggers, so the space used for their
1284           types and names is usually wasted: the types are usually small but
1285           the names are often not.  --ctf-variables causes the generation of
1286           such a section.  The default behaviour can be restored with
1287           --no-ctf-variables.
1288
1289       --ctf-share-types=method
1290           Adjust the method used to share types between translation units in
1291           CTF.
1292
1293           share-unconflicted
1294               Put all types that do not have ambiguous definitions into the
1295               shared dictionary, where debuggers can easily access them, even
1296               if they only occur in one translation unit.  This is the
1297               default.
1298
1299           share-duplicated
1300               Put only types that occur in multiple translation units into
1301               the shared dictionary: types with only one definition go into
1302               per-translation-unit dictionaries.  Types with ambiguous
1303               definitions in multiple translation units always go into per-
1304               translation-unit dictionaries.  This tends to make the CTF
1305               larger, but may reduce the amount of CTF in the shared
1306               dictionary.  For very large projects this may speed up opening
1307               the CTF and save memory in the CTF consumer at runtime.
1308
1309       --no-define-common
1310           This option inhibits the assignment of addresses to common symbols.
1311           The script command "INHIBIT_COMMON_ALLOCATION" has the same effect.
1312
1313           The --no-define-common option allows decoupling the decision to
1314           assign addresses to Common symbols from the choice of the output
1315           file type; otherwise a non-Relocatable output type forces assigning
1316           addresses to Common symbols.  Using --no-define-common allows
1317           Common symbols that are referenced from a shared library to be
1318           assigned addresses only in the main program.  This eliminates the
1319           unused duplicate space in the shared library, and also prevents any
1320           possible confusion over resolving to the wrong duplicate when there
1321           are many dynamic modules with specialized search paths for runtime
1322           symbol resolution.
1323
1324       --force-group-allocation
1325           This option causes the linker to place section group members like
1326           normal input sections, and to delete the section groups.  This is
1327           the default behaviour for a final link but this option can be used
1328           to change the behaviour of a relocatable link (-r).  The script
1329           command "FORCE_GROUP_ALLOCATION" has the same effect.
1330
1331       --defsym=symbol=expression
1332           Create a global symbol in the output file, containing the absolute
1333           address given by expression.  You may use this option as many times
1334           as necessary to define multiple symbols in the command line.  A
1335           limited form of arithmetic is supported for the expression in this
1336           context: you may give a hexadecimal constant or the name of an
1337           existing symbol, or use "+" and "-" to add or subtract hexadecimal
1338           constants or symbols.  If you need more elaborate expressions,
1339           consider using the linker command language from a script.  Note:
1340           there should be no white space between symbol, the equals sign
1341           ("="), and expression.
1342
1343           The linker processes --defsym arguments and -T arguments in order,
1344           placing --defsym before -T will define the symbol before the linker
1345           script from -T is processed, while placing --defsym after -T will
1346           define the symbol after the linker script has been processed.  This
1347           difference has consequences for expressions within the linker
1348           script that use the --defsym symbols, which order is correct will
1349           depend on what you are trying to achieve.
1350
1351       --demangle[=style]
1352       --no-demangle
1353           These options control whether to demangle symbol names in error
1354           messages and other output.  When the linker is told to demangle, it
1355           tries to present symbol names in a readable fashion: it strips
1356           leading underscores if they are used by the object file format, and
1357           converts C++ mangled symbol names into user readable names.
1358           Different compilers have different mangling styles.  The optional
1359           demangling style argument can be used to choose an appropriate
1360           demangling style for your compiler.  The linker will demangle by
1361           default unless the environment variable COLLECT_NO_DEMANGLE is set.
1362           These options may be used to override the default.
1363
1364       -Ifile
1365       --dynamic-linker=file
1366           Set the name of the dynamic linker.  This is only meaningful when
1367           generating dynamically linked ELF executables.  The default dynamic
1368           linker is normally correct; don't use this unless you know what you
1369           are doing.
1370
1371       --no-dynamic-linker
1372           When producing an executable file, omit the request for a dynamic
1373           linker to be used at load-time.  This is only meaningful for ELF
1374           executables that contain dynamic relocations, and usually requires
1375           entry point code that is capable of processing these relocations.
1376
1377       --embedded-relocs
1378           This option is similar to the --emit-relocs option except that the
1379           relocs are stored in a target-specific section.  This option is
1380           only supported by the BFIN, CR16 and M68K targets.
1381
1382       --disable-multiple-abs-defs
1383           Do not allow multiple definitions with symbols included in filename
1384           invoked by -R or --just-symbols
1385
1386       --fatal-warnings
1387       --no-fatal-warnings
1388           Treat all warnings as errors.  The default behaviour can be
1389           restored with the option --no-fatal-warnings.
1390
1391       --force-exe-suffix
1392           Make sure that an output file has a .exe suffix.
1393
1394           If a successfully built fully linked output file does not have a
1395           ".exe" or ".dll" suffix, this option forces the linker to copy the
1396           output file to one of the same name with a ".exe" suffix. This
1397           option is useful when using unmodified Unix makefiles on a
1398           Microsoft Windows host, since some versions of Windows won't run an
1399           image unless it ends in a ".exe" suffix.
1400
1401       --gc-sections
1402       --no-gc-sections
1403           Enable garbage collection of unused input sections.  It is ignored
1404           on targets that do not support this option.  The default behaviour
1405           (of not performing this garbage collection) can be restored by
1406           specifying --no-gc-sections on the command line.  Note that garbage
1407           collection for COFF and PE format targets is supported, but the
1408           implementation is currently considered to be experimental.
1409
1410           --gc-sections decides which input sections are used by examining
1411           symbols and relocations.  The section containing the entry symbol
1412           and all sections containing symbols undefined on the command-line
1413           will be kept, as will sections containing symbols referenced by
1414           dynamic objects.  Note that when building shared libraries, the
1415           linker must assume that any visible symbol is referenced.  Once
1416           this initial set of sections has been determined, the linker
1417           recursively marks as used any section referenced by their
1418           relocations.  See --entry, --undefined, and --gc-keep-exported.
1419
1420           This option can be set when doing a partial link (enabled with
1421           option -r).  In this case the root of symbols kept must be
1422           explicitly specified either by one of the options --entry,
1423           --undefined, or --gc-keep-exported or by a "ENTRY" command in the
1424           linker script.
1425
1426           As a GNU extension, ELF input sections marked with the
1427           "SHF_GNU_RETAIN" flag will not be garbage collected.
1428
1429       --print-gc-sections
1430       --no-print-gc-sections
1431           List all sections removed by garbage collection.  The listing is
1432           printed on stderr.  This option is only effective if garbage
1433           collection has been enabled via the --gc-sections) option.  The
1434           default behaviour (of not listing the sections that are removed)
1435           can be restored by specifying --no-print-gc-sections on the command
1436           line.
1437
1438       --gc-keep-exported
1439           When --gc-sections is enabled, this option prevents garbage
1440           collection of unused input sections that contain global symbols
1441           having default or protected visibility.  This option is intended to
1442           be used for executables where unreferenced sections would otherwise
1443           be garbage collected regardless of the external visibility of
1444           contained symbols.  Note that this option has no effect when
1445           linking shared objects since it is already the default behaviour.
1446           This option is only supported for ELF format targets.
1447
1448       --print-output-format
1449           Print the name of the default output format (perhaps influenced by
1450           other command-line options).  This is the string that would appear
1451           in an "OUTPUT_FORMAT" linker script command.
1452
1453       --print-memory-usage
1454           Print used size, total size and used size of memory regions created
1455           with the MEMORY command.  This is useful on embedded targets to
1456           have a quick view of amount of free memory.  The format of the
1457           output has one headline and one line per region.  It is both human
1458           readable and easily parsable by tools.  Here is an example of an
1459           output:
1460
1461                   Memory region         Used Size  Region Size  %age Used
1462                                ROM:        256 KB         1 MB     25.00%
1463                                RAM:          32 B         2 GB      0.00%
1464
1465       --help
1466           Print a summary of the command-line options on the standard output
1467           and exit.
1468
1469       --target-help
1470           Print a summary of all target-specific options on the standard
1471           output and exit.
1472
1473       -Map=mapfile
1474           Print a link map to the file mapfile.  See the description of the
1475           -M option, above.  If mapfile is just the character "-" then the
1476           map will be written to stdout.
1477
1478           Specifying a directory as mapfile causes the linker map to be
1479           written as a file inside the directory.  Normally name of the file
1480           inside the directory is computed as the basename of the output file
1481           with ".map" appended.   If however the special character "%" is
1482           used then this will be replaced by the full path of the output
1483           file.  Additionally if there are any characters after the % symbol
1484           then ".map" will no longer be appended.
1485
1486                    -o foo.exe -Map=bar                  [Creates ./bar]
1487                    -o ../dir/foo.exe -Map=bar           [Creates ./bar]
1488                    -o foo.exe -Map=../dir               [Creates ../dir/foo.exe.map]
1489                    -o ../dir2/foo.exe -Map=../dir       [Creates ../dir/foo.exe.map]
1490                    -o foo.exe -Map=%                    [Creates ./foo.exe.map]
1491                    -o ../dir/foo.exe -Map=%             [Creates ../dir/foo.exe.map]
1492                    -o foo.exe -Map=%.bar                [Creates ./foo.exe.bar]
1493                    -o ../dir/foo.exe -Map=%.bar         [Creates ../dir/foo.exe.bar]
1494                    -o ../dir2/foo.exe -Map=../dir/%     [Creates ../dir/../dir2/foo.exe.map]
1495                    -o ../dir2/foo.exe -Map=../dir/%.bar [Creates ../dir/../dir2/foo.exe.bar]
1496
1497           It is an error to specify more than one "%" character.
1498
1499           If the map file already exists then it will be overwritten by this
1500           operation.
1501
1502       --no-keep-memory
1503           ld normally optimizes for speed over memory usage by caching the
1504           symbol tables of input files in memory.  This option tells ld to
1505           instead optimize for memory usage, by rereading the symbol tables
1506           as necessary.  This may be required if ld runs out of memory space
1507           while linking a large executable.
1508
1509       --no-undefined
1510       -z defs
1511           Report unresolved symbol references from regular object files.
1512           This is done even if the linker is creating a non-symbolic shared
1513           library.  The switch --[no-]allow-shlib-undefined controls the
1514           behaviour for reporting unresolved references found in shared
1515           libraries being linked in.
1516
1517           The effects of this option can be reverted by using "-z undefs".
1518
1519       --allow-multiple-definition
1520       -z muldefs
1521           Normally when a symbol is defined multiple times, the linker will
1522           report a fatal error. These options allow multiple definitions and
1523           the first definition will be used.
1524
1525       --allow-shlib-undefined
1526       --no-allow-shlib-undefined
1527           Allows or disallows undefined symbols in shared libraries.  This
1528           switch is similar to --no-undefined except that it determines the
1529           behaviour when the undefined symbols are in a shared library rather
1530           than a regular object file.  It does not affect how undefined
1531           symbols in regular object files are handled.
1532
1533           The default behaviour is to report errors for any undefined symbols
1534           referenced in shared libraries if the linker is being used to
1535           create an executable, but to allow them if the linker is being used
1536           to create a shared library.
1537
1538           The reasons for allowing undefined symbol references in shared
1539           libraries specified at link time are that:
1540
1541           •   A shared library specified at link time may not be the same as
1542               the one that is available at load time, so the symbol might
1543               actually be resolvable at load time.
1544
1545           •   There are some operating systems, eg BeOS and HPPA, where
1546               undefined symbols in shared libraries are normal.
1547
1548               The BeOS kernel for example patches shared libraries at load
1549               time to select whichever function is most appropriate for the
1550               current architecture.  This is used, for example, to
1551               dynamically select an appropriate memset function.
1552
1553       --error-handling-script=scriptname
1554           If this option is provided then the linker will invoke scriptname
1555           whenever an error is encountered.  Currently however only two kinds
1556           of error are supported: missing symbols and missing libraries.  Two
1557           arguments will be passed to script: the keyword "undefined-symbol"
1558           or `missing-lib" and the name of the undefined symbol or missing
1559           library.  The intention is that the script will provide suggestions
1560           to the user as to where the symbol or library might be found.
1561           After the script has finished then the normal linker error message
1562           will be displayed.
1563
1564           The availability of this option is controlled by a configure time
1565           switch, so it may not be present in specific implementations.
1566
1567       --no-undefined-version
1568           Normally when a symbol has an undefined version, the linker will
1569           ignore it. This option disallows symbols with undefined version and
1570           a fatal error will be issued instead.
1571
1572       --default-symver
1573           Create and use a default symbol version (the soname) for
1574           unversioned exported symbols.
1575
1576       --default-imported-symver
1577           Create and use a default symbol version (the soname) for
1578           unversioned imported symbols.
1579
1580       --no-warn-mismatch
1581           Normally ld will give an error if you try to link together input
1582           files that are mismatched for some reason, perhaps because they
1583           have been compiled for different processors or for different
1584           endiannesses.  This option tells ld that it should silently permit
1585           such possible errors.  This option should only be used with care,
1586           in cases when you have taken some special action that ensures that
1587           the linker errors are inappropriate.
1588
1589       --no-warn-search-mismatch
1590           Normally ld will give a warning if it finds an incompatible library
1591           during a library search.  This option silences the warning.
1592
1593       --no-whole-archive
1594           Turn off the effect of the --whole-archive option for subsequent
1595           archive files.
1596
1597       --noinhibit-exec
1598           Retain the executable output file whenever it is still usable.
1599           Normally, the linker will not produce an output file if it
1600           encounters errors during the link process; it exits without writing
1601           an output file when it issues any error whatsoever.
1602
1603       -nostdlib
1604           Only search library directories explicitly specified on the command
1605           line.  Library directories specified in linker scripts (including
1606           linker scripts specified on the command line) are ignored.
1607
1608       --oformat=output-format
1609           ld may be configured to support more than one kind of object file.
1610           If your ld is configured this way, you can use the --oformat option
1611           to specify the binary format for the output object file.  Even when
1612           ld is configured to support alternative object formats, you don't
1613           usually need to specify this, as ld should be configured to produce
1614           as a default output format the most usual format on each machine.
1615           output-format is a text string, the name of a particular format
1616           supported by the BFD libraries.  (You can list the available binary
1617           formats with objdump -i.)  The script command "OUTPUT_FORMAT" can
1618           also specify the output format, but this option overrides it.
1619
1620       --out-implib file
1621           Create an import library in file corresponding to the executable
1622           the linker is generating (eg. a DLL or ELF program).  This import
1623           library (which should be called "*.dll.a" or "*.a" for DLLs) may be
1624           used to link clients against the generated executable; this
1625           behaviour makes it possible to skip a separate import library
1626           creation step (eg. "dlltool" for DLLs).  This option is only
1627           available for the i386 PE and ELF targetted ports of the linker.
1628
1629       -pie
1630       --pic-executable
1631           Create a position independent executable.  This is currently only
1632           supported on ELF platforms.  Position independent executables are
1633           similar to shared libraries in that they are relocated by the
1634           dynamic linker to the virtual address the OS chooses for them
1635           (which can vary between invocations).  Like normal dynamically
1636           linked executables they can be executed and symbols defined in the
1637           executable cannot be overridden by shared libraries.
1638
1639       -no-pie
1640           Create a position dependent executable.  This is the default.
1641
1642       -qmagic
1643           This option is ignored for Linux compatibility.
1644
1645       -Qy This option is ignored for SVR4 compatibility.
1646
1647       --relax
1648       --no-relax
1649           An option with machine dependent effects.  This option is only
1650           supported on a few targets.
1651
1652           On some platforms the --relax option performs target specific,
1653           global optimizations that become possible when the linker resolves
1654           addressing in the program, such as relaxing address modes,
1655           synthesizing new instructions, selecting shorter version of current
1656           instructions, and combining constant values.
1657
1658           On some platforms these link time global optimizations may make
1659           symbolic debugging of the resulting executable impossible.  This is
1660           known to be the case for the Matsushita MN10200 and MN10300 family
1661           of processors.
1662
1663           On platforms where the feature is supported, the option --no-relax
1664           will disable it.
1665
1666           On platforms where the feature is not supported, both --relax and
1667           --no-relax are accepted, but ignored.
1668
1669       --retain-symbols-file=filename
1670           Retain only the symbols listed in the file filename, discarding all
1671           others.  filename is simply a flat file, with one symbol name per
1672           line.  This option is especially useful in environments (such as
1673           VxWorks) where a large global symbol table is accumulated
1674           gradually, to conserve run-time memory.
1675
1676           --retain-symbols-file does not discard undefined symbols, or
1677           symbols needed for relocations.
1678
1679           You may only specify --retain-symbols-file once in the command
1680           line.  It overrides -s and -S.
1681
1682       -rpath=dir
1683           Add a directory to the runtime library search path.  This is used
1684           when linking an ELF executable with shared objects.  All -rpath
1685           arguments are concatenated and passed to the runtime linker, which
1686           uses them to locate shared objects at runtime.
1687
1688           The -rpath option is also used when locating shared objects which
1689           are needed by shared objects explicitly included in the link; see
1690           the description of the -rpath-link option.  Searching -rpath in
1691           this way is only supported by native linkers and cross linkers
1692           which have been configured with the --with-sysroot option.
1693
1694           If -rpath is not used when linking an ELF executable, the contents
1695           of the environment variable "LD_RUN_PATH" will be used if it is
1696           defined.
1697
1698           The -rpath option may also be used on SunOS.  By default, on SunOS,
1699           the linker will form a runtime search path out of all the -L
1700           options it is given.  If a -rpath option is used, the runtime
1701           search path will be formed exclusively using the -rpath options,
1702           ignoring the -L options.  This can be useful when using gcc, which
1703           adds many -L options which may be on NFS mounted file systems.
1704
1705           For compatibility with other ELF linkers, if the -R option is
1706           followed by a directory name, rather than a file name, it is
1707           treated as the -rpath option.
1708
1709       -rpath-link=dir
1710           When using ELF or SunOS, one shared library may require another.
1711           This happens when an "ld -shared" link includes a shared library as
1712           one of the input files.
1713
1714           When the linker encounters such a dependency when doing a non-
1715           shared, non-relocatable link, it will automatically try to locate
1716           the required shared library and include it in the link, if it is
1717           not included explicitly.  In such a case, the -rpath-link option
1718           specifies the first set of directories to search.  The -rpath-link
1719           option may specify a sequence of directory names either by
1720           specifying a list of names separated by colons, or by appearing
1721           multiple times.
1722
1723           The tokens $ORIGIN and $LIB can appear in these search directories.
1724           They will be replaced by the full path to the directory containing
1725           the program or shared object in the case of $ORIGIN and either lib
1726           - for 32-bit binaries - or lib64 - for 64-bit binaries - in the
1727           case of $LIB.
1728
1729           The alternative form of these tokens - ${ORIGIN} and ${LIB} can
1730           also be used.  The token $PLATFORM is not supported.
1731
1732           This option should be used with caution as it overrides the search
1733           path that may have been hard compiled into a shared library. In
1734           such a case it is possible to use unintentionally a different
1735           search path than the runtime linker would do.
1736
1737           The linker uses the following search paths to locate required
1738           shared libraries:
1739
1740           1.  Any directories specified by -rpath-link options.
1741
1742           2.  Any directories specified by -rpath options.  The difference
1743               between -rpath and -rpath-link is that directories specified by
1744               -rpath options are included in the executable and used at
1745               runtime, whereas the -rpath-link option is only effective at
1746               link time. Searching -rpath in this way is only supported by
1747               native linkers and cross linkers which have been configured
1748               with the --with-sysroot option.
1749
1750           3.  On an ELF system, for native linkers, if the -rpath and
1751               -rpath-link options were not used, search the contents of the
1752               environment variable "LD_RUN_PATH".
1753
1754           4.  On SunOS, if the -rpath option was not used, search any
1755               directories specified using -L options.
1756
1757           5.  For a native linker, search the contents of the environment
1758               variable "LD_LIBRARY_PATH".
1759
1760           6.  For a native ELF linker, the directories in "DT_RUNPATH" or
1761               "DT_RPATH" of a shared library are searched for shared
1762               libraries needed by it. The "DT_RPATH" entries are ignored if
1763               "DT_RUNPATH" entries exist.
1764
1765           7.  For a linker for a Linux system, if the file /etc/ld.so.conf
1766               exists, the list of directories found in that file.  Note: the
1767               path to this file is prefixed with the "sysroot" value, if that
1768               is defined, and then any "prefix" string if the linker was
1769               configured with the --prefix=<path> option.
1770
1771           8.  For a native linker on a FreeBSD system, any directories
1772               specified by the "_PATH_ELF_HINTS" macro defined in the
1773               elf-hints.h header file.
1774
1775           9.  Any directories specified by a "SEARCH_DIR" command in a linker
1776               script given on the command line, including scripts specified
1777               by -T (but not -dT).
1778
1779           10. The default directories, normally /lib and /usr/lib.
1780
1781           11. Any directories specified by a plugin
1782               LDPT_SET_EXTRA_LIBRARY_PATH.
1783
1784           12. Any directories specified by a "SEARCH_DIR" command in a
1785               default linker script.
1786
1787           Note however on Linux based systems there is an additional caveat:
1788           If the --as-needed option is active and a shared library is located
1789           which would normally satisfy the search and this library does not
1790           have DT_NEEDED tag for libc.so and there is a shared library later
1791           on in the set of search directories which also satisfies the search
1792           and this second shared library does have a DT_NEEDED tag for
1793           libc.so then the second library will be selected instead of the
1794           first.
1795
1796           If the required shared library is not found, the linker will issue
1797           a warning and continue with the link.
1798
1799       -shared
1800       -Bshareable
1801           Create a shared library.  This is currently only supported on ELF,
1802           XCOFF and SunOS platforms.  On SunOS, the linker will automatically
1803           create a shared library if the -e option is not used and there are
1804           undefined symbols in the link.
1805
1806       --sort-common
1807       --sort-common=ascending
1808       --sort-common=descending
1809           This option tells ld to sort the common symbols by alignment in
1810           ascending or descending order when it places them in the
1811           appropriate output sections.  The symbol alignments considered are
1812           sixteen-byte or larger, eight-byte, four-byte, two-byte, and one-
1813           byte. This is to prevent gaps between symbols due to alignment
1814           constraints.  If no sorting order is specified, then descending
1815           order is assumed.
1816
1817       --sort-section=name
1818           This option will apply "SORT_BY_NAME" to all wildcard section
1819           patterns in the linker script.
1820
1821       --sort-section=alignment
1822           This option will apply "SORT_BY_ALIGNMENT" to all wildcard section
1823           patterns in the linker script.
1824
1825       --spare-dynamic-tags=count
1826           This option specifies the number of empty slots to leave in the
1827           .dynamic section of ELF shared objects.  Empty slots may be needed
1828           by post processing tools, such as the prelinker.  The default is 5.
1829
1830       --split-by-file[=size]
1831           Similar to --split-by-reloc but creates a new output section for
1832           each input file when size is reached.  size defaults to a size of 1
1833           if not given.
1834
1835       --split-by-reloc[=count]
1836           Tries to creates extra sections in the output file so that no
1837           single output section in the file contains more than count
1838           relocations.  This is useful when generating huge relocatable files
1839           for downloading into certain real time kernels with the COFF object
1840           file format; since COFF cannot represent more than 65535
1841           relocations in a single section.  Note that this will fail to work
1842           with object file formats which do not support arbitrary sections.
1843           The linker will not split up individual input sections for
1844           redistribution, so if a single input section contains more than
1845           count relocations one output section will contain that many
1846           relocations.  count defaults to a value of 32768.
1847
1848       --stats
1849           Compute and display statistics about the operation of the linker,
1850           such as execution time and memory usage.
1851
1852       --sysroot=directory
1853           Use directory as the location of the sysroot, overriding the
1854           configure-time default.  This option is only supported by linkers
1855           that were configured using --with-sysroot.
1856
1857       --task-link
1858           This is used by COFF/PE based targets to create a task-linked
1859           object file where all of the global symbols have been converted to
1860           statics.
1861
1862       --traditional-format
1863           For some targets, the output of ld is different in some ways from
1864           the output of some existing linker.  This switch requests ld to use
1865           the traditional format instead.
1866
1867           For example, on SunOS, ld combines duplicate entries in the symbol
1868           string table.  This can reduce the size of an output file with full
1869           debugging information by over 30 percent.  Unfortunately, the SunOS
1870           "dbx" program can not read the resulting program ("gdb" has no
1871           trouble).  The --traditional-format switch tells ld to not combine
1872           duplicate entries.
1873
1874       --section-start=sectionname=org
1875           Locate a section in the output file at the absolute address given
1876           by org.  You may use this option as many times as necessary to
1877           locate multiple sections in the command line.  org must be a single
1878           hexadecimal integer; for compatibility with other linkers, you may
1879           omit the leading 0x usually associated with hexadecimal values.
1880           Note: there should be no white space between sectionname, the
1881           equals sign ("="), and org.
1882
1883       -Tbss=org
1884       -Tdata=org
1885       -Ttext=org
1886           Same as --section-start, with ".bss", ".data" or ".text" as the
1887           sectionname.
1888
1889       -Ttext-segment=org
1890           When creating an ELF executable, it will set the address of the
1891           first byte of the text segment.
1892
1893       -Trodata-segment=org
1894           When creating an ELF executable or shared object for a target where
1895           the read-only data is in its own segment separate from the
1896           executable text, it will set the address of the first byte of the
1897           read-only data segment.
1898
1899       -Tldata-segment=org
1900           When creating an ELF executable or shared object for x86-64 medium
1901           memory model, it will set the address of the first byte of the
1902           ldata segment.
1903
1904       --unresolved-symbols=method
1905           Determine how to handle unresolved symbols.  There are four
1906           possible values for method:
1907
1908           ignore-all
1909               Do not report any unresolved symbols.
1910
1911           report-all
1912               Report all unresolved symbols.  This is the default.
1913
1914           ignore-in-object-files
1915               Report unresolved symbols that are contained in shared
1916               libraries, but ignore them if they come from regular object
1917               files.
1918
1919           ignore-in-shared-libs
1920               Report unresolved symbols that come from regular object files,
1921               but ignore them if they come from shared libraries.  This can
1922               be useful when creating a dynamic binary and it is known that
1923               all the shared libraries that it should be referencing are
1924               included on the linker's command line.
1925
1926           The behaviour for shared libraries on their own can also be
1927           controlled by the --[no-]allow-shlib-undefined option.
1928
1929           Normally the linker will generate an error message for each
1930           reported unresolved symbol but the option --warn-unresolved-symbols
1931           can change this to a warning.
1932
1933       --dll-verbose
1934       --verbose[=NUMBER]
1935           Display the version number for ld and list the linker emulations
1936           supported.  Display which input files can and cannot be opened.
1937           Display the linker script being used by the linker. If the optional
1938           NUMBER argument > 1, plugin symbol status will also be displayed.
1939
1940       --version-script=version-scriptfile
1941           Specify the name of a version script to the linker.  This is
1942           typically used when creating shared libraries to specify additional
1943           information about the version hierarchy for the library being
1944           created.  This option is only fully supported on ELF platforms
1945           which support shared libraries; see VERSION.  It is partially
1946           supported on PE platforms, which can use version scripts to filter
1947           symbol visibility in auto-export mode: any symbols marked local in
1948           the version script will not be exported.
1949
1950       --warn-common
1951           Warn when a common symbol is combined with another common symbol or
1952           with a symbol definition.  Unix linkers allow this somewhat sloppy
1953           practice, but linkers on some other operating systems do not.  This
1954           option allows you to find potential problems from combining global
1955           symbols.  Unfortunately, some C libraries use this practice, so you
1956           may get some warnings about symbols in the libraries as well as in
1957           your programs.
1958
1959           There are three kinds of global symbols, illustrated here by C
1960           examples:
1961
1962           int i = 1;
1963               A definition, which goes in the initialized data section of the
1964               output file.
1965
1966           extern int i;
1967               An undefined reference, which does not allocate space.  There
1968               must be either a definition or a common symbol for the variable
1969               somewhere.
1970
1971           int i;
1972               A common symbol.  If there are only (one or more) common
1973               symbols for a variable, it goes in the uninitialized data area
1974               of the output file.  The linker merges multiple common symbols
1975               for the same variable into a single symbol.  If they are of
1976               different sizes, it picks the largest size.  The linker turns a
1977               common symbol into a declaration, if there is a definition of
1978               the same variable.
1979
1980           The --warn-common option can produce five kinds of warnings.  Each
1981           warning consists of a pair of lines: the first describes the symbol
1982           just encountered, and the second describes the previous symbol
1983           encountered with the same name.  One or both of the two symbols
1984           will be a common symbol.
1985
1986           1.  Turning a common symbol into a reference, because there is
1987               already a definition for the symbol.
1988
1989                       <file>(<section>): warning: common of `<symbol>'
1990                          overridden by definition
1991                       <file>(<section>): warning: defined here
1992
1993           2.  Turning a common symbol into a reference, because a later
1994               definition for the symbol is encountered.  This is the same as
1995               the previous case, except that the symbols are encountered in a
1996               different order.
1997
1998                       <file>(<section>): warning: definition of `<symbol>'
1999                          overriding common
2000                       <file>(<section>): warning: common is here
2001
2002           3.  Merging a common symbol with a previous same-sized common
2003               symbol.
2004
2005                       <file>(<section>): warning: multiple common
2006                          of `<symbol>'
2007                       <file>(<section>): warning: previous common is here
2008
2009           4.  Merging a common symbol with a previous larger common symbol.
2010
2011                       <file>(<section>): warning: common of `<symbol>'
2012                          overridden by larger common
2013                       <file>(<section>): warning: larger common is here
2014
2015           5.  Merging a common symbol with a previous smaller common symbol.
2016               This is the same as the previous case, except that the symbols
2017               are encountered in a different order.
2018
2019                       <file>(<section>): warning: common of `<symbol>'
2020                          overriding smaller common
2021                       <file>(<section>): warning: smaller common is here
2022
2023       --warn-constructors
2024           Warn if any global constructors are used.  This is only useful for
2025           a few object file formats.  For formats like COFF or ELF, the
2026           linker can not detect the use of global constructors.
2027
2028       --warn-multiple-gp
2029           Warn if multiple global pointer values are required in the output
2030           file.  This is only meaningful for certain processors, such as the
2031           Alpha.  Specifically, some processors put large-valued constants in
2032           a special section.  A special register (the global pointer) points
2033           into the middle of this section, so that constants can be loaded
2034           efficiently via a base-register relative addressing mode.  Since
2035           the offset in base-register relative mode is fixed and relatively
2036           small (e.g., 16 bits), this limits the maximum size of the constant
2037           pool.  Thus, in large programs, it is often necessary to use
2038           multiple global pointer values in order to be able to address all
2039           possible constants.  This option causes a warning to be issued
2040           whenever this case occurs.
2041
2042       --warn-once
2043           Only warn once for each undefined symbol, rather than once per
2044           module which refers to it.
2045
2046       --warn-section-align
2047           Warn if the address of an output section is changed because of
2048           alignment.  Typically, the alignment will be set by an input
2049           section.  The address will only be changed if it not explicitly
2050           specified; that is, if the "SECTIONS" command does not specify a
2051           start address for the section.
2052
2053       --warn-textrel
2054           Warn if the linker adds DT_TEXTREL to a position-independent
2055           executable or shared object.
2056
2057       --warn-alternate-em
2058           Warn if an object has alternate ELF machine code.
2059
2060       --warn-unresolved-symbols
2061           If the linker is going to report an unresolved symbol (see the
2062           option --unresolved-symbols) it will normally generate an error.
2063           This option makes it generate a warning instead.
2064
2065       --error-unresolved-symbols
2066           This restores the linker's default behaviour of generating errors
2067           when it is reporting unresolved symbols.
2068
2069       --whole-archive
2070           For each archive mentioned on the command line after the
2071           --whole-archive option, include every object file in the archive in
2072           the link, rather than searching the archive for the required object
2073           files.  This is normally used to turn an archive file into a shared
2074           library, forcing every object to be included in the resulting
2075           shared library.  This option may be used more than once.
2076
2077           Two notes when using this option from gcc: First, gcc doesn't know
2078           about this option, so you have to use -Wl,-whole-archive.  Second,
2079           don't forget to use -Wl,-no-whole-archive after your list of
2080           archives, because gcc will add its own list of archives to your
2081           link and you may not want this flag to affect those as well.
2082
2083       --wrap=symbol
2084           Use a wrapper function for symbol.  Any undefined reference to
2085           symbol will be resolved to "__wrap_symbol".  Any undefined
2086           reference to "__real_symbol" will be resolved to symbol.
2087
2088           This can be used to provide a wrapper for a system function.  The
2089           wrapper function should be called "__wrap_symbol".  If it wishes to
2090           call the system function, it should call "__real_symbol".
2091
2092           Here is a trivial example:
2093
2094                   void *
2095                   __wrap_malloc (size_t c)
2096                   {
2097                     printf ("malloc called with %zu\n", c);
2098                     return __real_malloc (c);
2099                   }
2100
2101           If you link other code with this file using --wrap malloc, then all
2102           calls to "malloc" will call the function "__wrap_malloc" instead.
2103           The call to "__real_malloc" in "__wrap_malloc" will call the real
2104           "malloc" function.
2105
2106           You may wish to provide a "__real_malloc" function as well, so that
2107           links without the --wrap option will succeed.  If you do this, you
2108           should not put the definition of "__real_malloc" in the same file
2109           as "__wrap_malloc"; if you do, the assembler may resolve the call
2110           before the linker has a chance to wrap it to "malloc".
2111
2112           Only undefined references are replaced by the linker.  So,
2113           translation unit internal references to symbol are not resolved to
2114           "__wrap_symbol".  In the next example, the call to "f" in "g" is
2115           not resolved to "__wrap_f".
2116
2117                   int
2118                   f (void)
2119                   {
2120                     return 123;
2121                   }
2122
2123                   int
2124                   g (void)
2125                   {
2126                     return f();
2127                   }
2128
2129       --eh-frame-hdr
2130       --no-eh-frame-hdr
2131           Request (--eh-frame-hdr) or suppress (--no-eh-frame-hdr) the
2132           creation of ".eh_frame_hdr" section and ELF "PT_GNU_EH_FRAME"
2133           segment header.
2134
2135       --no-ld-generated-unwind-info
2136           Request creation of ".eh_frame" unwind info for linker generated
2137           code sections like PLT.  This option is on by default if linker
2138           generated unwind info is supported.
2139
2140       --enable-new-dtags
2141       --disable-new-dtags
2142           This linker can create the new dynamic tags in ELF. But the older
2143           ELF systems may not understand them. If you specify
2144           --enable-new-dtags, the new dynamic tags will be created as needed
2145           and older dynamic tags will be omitted.  If you specify
2146           --disable-new-dtags, no new dynamic tags will be created. By
2147           default, the new dynamic tags are not created. Note that those
2148           options are only available for ELF systems.
2149
2150       --hash-size=number
2151           Set the default size of the linker's hash tables to a prime number
2152           close to number.  Increasing this value can reduce the length of
2153           time it takes the linker to perform its tasks, at the expense of
2154           increasing the linker's memory requirements.  Similarly reducing
2155           this value can reduce the memory requirements at the expense of
2156           speed.
2157
2158       --hash-style=style
2159           Set the type of linker's hash table(s).  style can be either "sysv"
2160           for classic ELF ".hash" section, "gnu" for new style GNU
2161           ".gnu.hash" section or "both" for both the classic ELF ".hash" and
2162           new style GNU ".gnu.hash" hash tables.  The default depends upon
2163           how the linker was configured, but for most Linux based systems it
2164           will be "both".
2165
2166       --compress-debug-sections=none
2167       --compress-debug-sections=zlib
2168       --compress-debug-sections=zlib-gnu
2169       --compress-debug-sections=zlib-gabi
2170           On ELF platforms, these options control how DWARF debug sections
2171           are compressed using zlib.
2172
2173           --compress-debug-sections=none doesn't compress DWARF debug
2174           sections.  --compress-debug-sections=zlib-gnu compresses DWARF
2175           debug sections and renames them to begin with .zdebug instead of
2176           .debug.  --compress-debug-sections=zlib-gabi also compresses DWARF
2177           debug sections, but rather than renaming them it sets the
2178           SHF_COMPRESSED flag in the sections' headers.
2179
2180           The --compress-debug-sections=zlib option is an alias for
2181           --compress-debug-sections=zlib-gabi.
2182
2183           Note that this option overrides any compression in input debug
2184           sections, so if a binary is linked with
2185           --compress-debug-sections=none for example, then any compressed
2186           debug sections in input files will be uncompressed before they are
2187           copied into the output binary.
2188
2189           The default compression behaviour varies depending upon the target
2190           involved and the configure options used to build the toolchain.
2191           The default can be determined by examining the output from the
2192           linker's --help option.
2193
2194       --reduce-memory-overheads
2195           This option reduces memory requirements at ld runtime, at the
2196           expense of linking speed.  This was introduced to select the old
2197           O(n^2) algorithm for link map file generation, rather than the new
2198           O(n) algorithm which uses about 40% more memory for symbol storage.
2199
2200           Another effect of the switch is to set the default hash table size
2201           to 1021, which again saves memory at the cost of lengthening the
2202           linker's run time.  This is not done however if the --hash-size
2203           switch has been used.
2204
2205           The --reduce-memory-overheads switch may be also be used to enable
2206           other tradeoffs in future versions of the linker.
2207
2208       --build-id
2209       --build-id=style
2210           Request the creation of a ".note.gnu.build-id" ELF note section or
2211           a ".buildid" COFF section.  The contents of the note are unique
2212           bits identifying this linked file.  style can be "uuid" to use 128
2213           random bits, "sha1" to use a 160-bit SHA1 hash on the normative
2214           parts of the output contents, "md5" to use a 128-bit MD5 hash on
2215           the normative parts of the output contents, or "0xhexstring" to use
2216           a chosen bit string specified as an even number of hexadecimal
2217           digits ("-" and ":" characters between digit pairs are ignored).
2218           If style is omitted, "sha1" is used.
2219
2220           The "md5" and "sha1" styles produces an identifier that is always
2221           the same in an identical output file, but will be unique among all
2222           nonidentical output files.  It is not intended to be compared as a
2223           checksum for the file's contents.  A linked file may be changed
2224           later by other tools, but the build ID bit string identifying the
2225           original linked file does not change.
2226
2227           Passing "none" for style disables the setting from any "--build-id"
2228           options earlier on the command line.
2229
2230       The i386 PE linker supports the -shared option, which causes the output
2231       to be a dynamically linked library (DLL) instead of a normal
2232       executable.  You should name the output "*.dll" when you use this
2233       option.  In addition, the linker fully supports the standard "*.def"
2234       files, which may be specified on the linker command line like an object
2235       file (in fact, it should precede archives it exports symbols from, to
2236       ensure that they get linked in, just like a normal object file).
2237
2238       In addition to the options common to all targets, the i386 PE linker
2239       support additional command-line options that are specific to the i386
2240       PE target.  Options that take values may be separated from their values
2241       by either a space or an equals sign.
2242
2243       --add-stdcall-alias
2244           If given, symbols with a stdcall suffix (@nn) will be exported as-
2245           is and also with the suffix stripped.  [This option is specific to
2246           the i386 PE targeted port of the linker]
2247
2248       --base-file file
2249           Use file as the name of a file in which to save the base addresses
2250           of all the relocations needed for generating DLLs with dlltool.
2251           [This is an i386 PE specific option]
2252
2253       --dll
2254           Create a DLL instead of a regular executable.  You may also use
2255           -shared or specify a "LIBRARY" in a given ".def" file.  [This
2256           option is specific to the i386 PE targeted port of the linker]
2257
2258       --enable-long-section-names
2259       --disable-long-section-names
2260           The PE variants of the COFF object format add an extension that
2261           permits the use of section names longer than eight characters, the
2262           normal limit for COFF.  By default, these names are only allowed in
2263           object files, as fully-linked executable images do not carry the
2264           COFF string table required to support the longer names.  As a GNU
2265           extension, it is possible to allow their use in executable images
2266           as well, or to (probably pointlessly!)  disallow it in object
2267           files, by using these two options.  Executable images generated
2268           with these long section names are slightly non-standard, carrying
2269           as they do a string table, and may generate confusing output when
2270           examined with non-GNU PE-aware tools, such as file viewers and
2271           dumpers.  However, GDB relies on the use of PE long section names
2272           to find Dwarf-2 debug information sections in an executable image
2273           at runtime, and so if neither option is specified on the command-
2274           line, ld will enable long section names, overriding the default and
2275           technically correct behaviour, when it finds the presence of debug
2276           information while linking an executable image and not stripping
2277           symbols.  [This option is valid for all PE targeted ports of the
2278           linker]
2279
2280       --enable-stdcall-fixup
2281       --disable-stdcall-fixup
2282           If the link finds a symbol that it cannot resolve, it will attempt
2283           to do "fuzzy linking" by looking for another defined symbol that
2284           differs only in the format of the symbol name (cdecl vs stdcall)
2285           and will resolve that symbol by linking to the match.  For example,
2286           the undefined symbol "_foo" might be linked to the function
2287           "_foo@12", or the undefined symbol "_bar@16" might be linked to the
2288           function "_bar".  When the linker does this, it prints a warning,
2289           since it normally should have failed to link, but sometimes import
2290           libraries generated from third-party dlls may need this feature to
2291           be usable.  If you specify --enable-stdcall-fixup, this feature is
2292           fully enabled and warnings are not printed.  If you specify
2293           --disable-stdcall-fixup, this feature is disabled and such
2294           mismatches are considered to be errors.  [This option is specific
2295           to the i386 PE targeted port of the linker]
2296
2297       --leading-underscore
2298       --no-leading-underscore
2299           For most targets default symbol-prefix is an underscore and is
2300           defined in target's description. By this option it is possible to
2301           disable/enable the default underscore symbol-prefix.
2302
2303       --export-all-symbols
2304           If given, all global symbols in the objects used to build a DLL
2305           will be exported by the DLL.  Note that this is the default if
2306           there otherwise wouldn't be any exported symbols.  When symbols are
2307           explicitly exported via DEF files or implicitly exported via
2308           function attributes, the default is to not export anything else
2309           unless this option is given.  Note that the symbols "DllMain@12",
2310           "DllEntryPoint@0", "DllMainCRTStartup@12", and "impure_ptr" will
2311           not be automatically exported.  Also, symbols imported from other
2312           DLLs will not be re-exported, nor will symbols specifying the DLL's
2313           internal layout such as those beginning with "_head_" or ending
2314           with "_iname".  In addition, no symbols from "libgcc", "libstd++",
2315           "libmingw32", or "crtX.o" will be exported.  Symbols whose names
2316           begin with "__rtti_" or "__builtin_" will not be exported, to help
2317           with C++ DLLs.  Finally, there is an extensive list of cygwin-
2318           private symbols that are not exported (obviously, this applies on
2319           when building DLLs for cygwin targets).  These cygwin-excludes are:
2320           "_cygwin_dll_entry@12", "_cygwin_crt0_common@8",
2321           "_cygwin_noncygwin_dll_entry@12", "_fmode", "_impure_ptr",
2322           "cygwin_attach_dll", "cygwin_premain0", "cygwin_premain1",
2323           "cygwin_premain2", "cygwin_premain3", and "environ".  [This option
2324           is specific to the i386 PE targeted port of the linker]
2325
2326       --exclude-symbols symbol,symbol,...
2327           Specifies a list of symbols which should not be automatically
2328           exported.  The symbol names may be delimited by commas or colons.
2329           [This option is specific to the i386 PE targeted port of the
2330           linker]
2331
2332       --exclude-all-symbols
2333           Specifies no symbols should be automatically exported.  [This
2334           option is specific to the i386 PE targeted port of the linker]
2335
2336       --file-alignment
2337           Specify the file alignment.  Sections in the file will always begin
2338           at file offsets which are multiples of this number.  This defaults
2339           to 512.  [This option is specific to the i386 PE targeted port of
2340           the linker]
2341
2342       --heap reserve
2343       --heap reserve,commit
2344           Specify the number of bytes of memory to reserve (and optionally
2345           commit) to be used as heap for this program.  The default is 1MB
2346           reserved, 4K committed.  [This option is specific to the i386 PE
2347           targeted port of the linker]
2348
2349       --image-base value
2350           Use value as the base address of your program or dll.  This is the
2351           lowest memory location that will be used when your program or dll
2352           is loaded.  To reduce the need to relocate and improve performance
2353           of your dlls, each should have a unique base address and not
2354           overlap any other dlls.  The default is 0x400000 for executables,
2355           and 0x10000000 for dlls.  [This option is specific to the i386 PE
2356           targeted port of the linker]
2357
2358       --kill-at
2359           If given, the stdcall suffixes (@nn) will be stripped from symbols
2360           before they are exported.  [This option is specific to the i386 PE
2361           targeted port of the linker]
2362
2363       --large-address-aware
2364           If given, the appropriate bit in the "Characteristics" field of the
2365           COFF header is set to indicate that this executable supports
2366           virtual addresses greater than 2 gigabytes.  This should be used in
2367           conjunction with the /3GB or /USERVA=value megabytes switch in the
2368           "[operating systems]" section of the BOOT.INI.  Otherwise, this bit
2369           has no effect.  [This option is specific to PE targeted ports of
2370           the linker]
2371
2372       --disable-large-address-aware
2373           Reverts the effect of a previous --large-address-aware option.
2374           This is useful if --large-address-aware is always set by the
2375           compiler driver (e.g. Cygwin gcc) and the executable does not
2376           support virtual addresses greater than 2 gigabytes.  [This option
2377           is specific to PE targeted ports of the linker]
2378
2379       --major-image-version value
2380           Sets the major number of the "image version".  Defaults to 1.
2381           [This option is specific to the i386 PE targeted port of the
2382           linker]
2383
2384       --major-os-version value
2385           Sets the major number of the "os version".  Defaults to 4.  [This
2386           option is specific to the i386 PE targeted port of the linker]
2387
2388       --major-subsystem-version value
2389           Sets the major number of the "subsystem version".  Defaults to 4.
2390           [This option is specific to the i386 PE targeted port of the
2391           linker]
2392
2393       --minor-image-version value
2394           Sets the minor number of the "image version".  Defaults to 0.
2395           [This option is specific to the i386 PE targeted port of the
2396           linker]
2397
2398       --minor-os-version value
2399           Sets the minor number of the "os version".  Defaults to 0.  [This
2400           option is specific to the i386 PE targeted port of the linker]
2401
2402       --minor-subsystem-version value
2403           Sets the minor number of the "subsystem version".  Defaults to 0.
2404           [This option is specific to the i386 PE targeted port of the
2405           linker]
2406
2407       --output-def file
2408           The linker will create the file file which will contain a DEF file
2409           corresponding to the DLL the linker is generating.  This DEF file
2410           (which should be called "*.def") may be used to create an import
2411           library with "dlltool" or may be used as a reference to
2412           automatically or implicitly exported symbols.  [This option is
2413           specific to the i386 PE targeted port of the linker]
2414
2415       --enable-auto-image-base
2416       --enable-auto-image-base=value
2417           Automatically choose the image base for DLLs, optionally starting
2418           with base value, unless one is specified using the "--image-base"
2419           argument.  By using a hash generated from the dllname to create
2420           unique image bases for each DLL, in-memory collisions and
2421           relocations which can delay program execution are avoided.  [This
2422           option is specific to the i386 PE targeted port of the linker]
2423
2424       --disable-auto-image-base
2425           Do not automatically generate a unique image base.  If there is no
2426           user-specified image base ("--image-base") then use the platform
2427           default.  [This option is specific to the i386 PE targeted port of
2428           the linker]
2429
2430       --dll-search-prefix string
2431           When linking dynamically to a dll without an import library, search
2432           for "<string><basename>.dll" in preference to "lib<basename>.dll".
2433           This behaviour allows easy distinction between DLLs built for the
2434           various "subplatforms": native, cygwin, uwin, pw, etc.  For
2435           instance, cygwin DLLs typically use "--dll-search-prefix=cyg".
2436           [This option is specific to the i386 PE targeted port of the
2437           linker]
2438
2439       --enable-auto-import
2440           Do sophisticated linking of "_symbol" to "__imp__symbol" for DATA
2441           imports from DLLs, thus making it possible to bypass the dllimport
2442           mechanism on the user side and to reference unmangled symbol names.
2443           [This option is specific to the i386 PE targeted port of the
2444           linker]
2445
2446           The following remarks pertain to the original implementation of the
2447           feature and are obsolete nowadays for Cygwin and MinGW targets.
2448
2449           Note: Use of the 'auto-import' extension will cause the text
2450           section of the image file to be made writable. This does not
2451           conform to the PE-COFF format specification published by Microsoft.
2452
2453           Note - use of the 'auto-import' extension will also cause read only
2454           data which would normally be placed into the .rdata section to be
2455           placed into the .data section instead.  This is in order to work
2456           around a problem with consts that is described here:
2457           http://www.cygwin.com/ml/cygwin/2004-09/msg01101.html
2458
2459           Using 'auto-import' generally will 'just work' -- but sometimes you
2460           may see this message:
2461
2462           "variable '<var>' can't be auto-imported. Please read the
2463           documentation for ld's "--enable-auto-import" for details."
2464
2465           This message occurs when some (sub)expression accesses an address
2466           ultimately given by the sum of two constants (Win32 import tables
2467           only allow one).  Instances where this may occur include accesses
2468           to member fields of struct variables imported from a DLL, as well
2469           as using a constant index into an array variable imported from a
2470           DLL.  Any multiword variable (arrays, structs, long long, etc) may
2471           trigger this error condition.  However, regardless of the exact
2472           data type of the offending exported variable, ld will always detect
2473           it, issue the warning, and exit.
2474
2475           There are several ways to address this difficulty, regardless of
2476           the data type of the exported variable:
2477
2478           One way is to use --enable-runtime-pseudo-reloc switch. This leaves
2479           the task of adjusting references in your client code for runtime
2480           environment, so this method works only when runtime environment
2481           supports this feature.
2482
2483           A second solution is to force one of the 'constants' to be a
2484           variable -- that is, unknown and un-optimizable at compile time.
2485           For arrays, there are two possibilities: a) make the indexee (the
2486           array's address) a variable, or b) make the 'constant' index a
2487           variable.  Thus:
2488
2489                   extern type extern_array[];
2490                   extern_array[1] -->
2491                      { volatile type *t=extern_array; t[1] }
2492
2493           or
2494
2495                   extern type extern_array[];
2496                   extern_array[1] -->
2497                      { volatile int t=1; extern_array[t] }
2498
2499           For structs (and most other multiword data types) the only option
2500           is to make the struct itself (or the long long, or the ...)
2501           variable:
2502
2503                   extern struct s extern_struct;
2504                   extern_struct.field -->
2505                      { volatile struct s *t=&extern_struct; t->field }
2506
2507           or
2508
2509                   extern long long extern_ll;
2510                   extern_ll -->
2511                     { volatile long long * local_ll=&extern_ll; *local_ll }
2512
2513           A third method of dealing with this difficulty is to abandon
2514           'auto-import' for the offending symbol and mark it with
2515           "__declspec(dllimport)".  However, in practice that requires using
2516           compile-time #defines to indicate whether you are building a DLL,
2517           building client code that will link to the DLL, or merely
2518           building/linking to a static library.   In making the choice
2519           between the various methods of resolving the 'direct address with
2520           constant offset' problem, you should consider typical real-world
2521           usage:
2522
2523           Original:
2524
2525                   --foo.h
2526                   extern int arr[];
2527                   --foo.c
2528                   #include "foo.h"
2529                   void main(int argc, char **argv){
2530                     printf("%d\n",arr[1]);
2531                   }
2532
2533           Solution 1:
2534
2535                   --foo.h
2536                   extern int arr[];
2537                   --foo.c
2538                   #include "foo.h"
2539                   void main(int argc, char **argv){
2540                     /* This workaround is for win32 and cygwin; do not "optimize" */
2541                     volatile int *parr = arr;
2542                     printf("%d\n",parr[1]);
2543                   }
2544
2545           Solution 2:
2546
2547                   --foo.h
2548                   /* Note: auto-export is assumed (no __declspec(dllexport)) */
2549                   #if (defined(_WIN32) || defined(__CYGWIN__)) && \
2550                     !(defined(FOO_BUILD_DLL) || defined(FOO_STATIC))
2551                   #define FOO_IMPORT __declspec(dllimport)
2552                   #else
2553                   #define FOO_IMPORT
2554                   #endif
2555                   extern FOO_IMPORT int arr[];
2556                   --foo.c
2557                   #include "foo.h"
2558                   void main(int argc, char **argv){
2559                     printf("%d\n",arr[1]);
2560                   }
2561
2562           A fourth way to avoid this problem is to re-code your library to
2563           use a functional interface rather than a data interface for the
2564           offending variables (e.g. set_foo() and get_foo() accessor
2565           functions).
2566
2567       --disable-auto-import
2568           Do not attempt to do sophisticated linking of "_symbol" to
2569           "__imp__symbol" for DATA imports from DLLs.  [This option is
2570           specific to the i386 PE targeted port of the linker]
2571
2572       --enable-runtime-pseudo-reloc
2573           If your code contains expressions described in --enable-auto-import
2574           section, that is, DATA imports from DLL with non-zero offset, this
2575           switch will create a vector of 'runtime pseudo relocations' which
2576           can be used by runtime environment to adjust references to such
2577           data in your client code.  [This option is specific to the i386 PE
2578           targeted port of the linker]
2579
2580       --disable-runtime-pseudo-reloc
2581           Do not create pseudo relocations for non-zero offset DATA imports
2582           from DLLs.  [This option is specific to the i386 PE targeted port
2583           of the linker]
2584
2585       --enable-extra-pe-debug
2586           Show additional debug info related to auto-import symbol thunking.
2587           [This option is specific to the i386 PE targeted port of the
2588           linker]
2589
2590       --section-alignment
2591           Sets the section alignment.  Sections in memory will always begin
2592           at addresses which are a multiple of this number.  Defaults to
2593           0x1000.  [This option is specific to the i386 PE targeted port of
2594           the linker]
2595
2596       --stack reserve
2597       --stack reserve,commit
2598           Specify the number of bytes of memory to reserve (and optionally
2599           commit) to be used as stack for this program.  The default is 2MB
2600           reserved, 4K committed.  [This option is specific to the i386 PE
2601           targeted port of the linker]
2602
2603       --subsystem which
2604       --subsystem which:major
2605       --subsystem which:major.minor
2606           Specifies the subsystem under which your program will execute.  The
2607           legal values for which are "native", "windows", "console", "posix",
2608           and "xbox".  You may optionally set the subsystem version also.
2609           Numeric values are also accepted for which.  [This option is
2610           specific to the i386 PE targeted port of the linker]
2611
2612           The following options set flags in the "DllCharacteristics" field
2613           of the PE file header: [These options are specific to PE targeted
2614           ports of the linker]
2615
2616       --high-entropy-va
2617       --disable-high-entropy-va
2618           Image is compatible with 64-bit address space layout randomization
2619           (ASLR).  This option is enabled by default for 64-bit PE images.
2620
2621           This option also implies --dynamicbase and --enable-reloc-section.
2622
2623       --dynamicbase
2624       --disable-dynamicbase
2625           The image base address may be relocated using address space layout
2626           randomization (ASLR).  This feature was introduced with MS Windows
2627           Vista for i386 PE targets.  This option is enabled by default but
2628           can be disabled via the --disable-dynamicbase option.  This option
2629           also implies --enable-reloc-section.
2630
2631       --forceinteg
2632       --disable-forceinteg
2633           Code integrity checks are enforced.  This option is disabled by
2634           default.
2635
2636       --nxcompat
2637       --disable-nxcompat
2638           The image is compatible with the Data Execution Prevention.  This
2639           feature was introduced with MS Windows XP SP2 for i386 PE targets.
2640           The option is enabled by default.
2641
2642       --no-isolation
2643       --disable-no-isolation
2644           Although the image understands isolation, do not isolate the image.
2645           This option is disabled by default.
2646
2647       --no-seh
2648       --disable-no-seh
2649           The image does not use SEH. No SE handler may be called from this
2650           image.  This option is disabled by default.
2651
2652       --no-bind
2653       --disable-no-bind
2654           Do not bind this image.  This option is disabled by default.
2655
2656       --wdmdriver
2657       --disable-wdmdriver
2658           The driver uses the MS Windows Driver Model.  This option is
2659           disabled by default.
2660
2661       --tsaware
2662       --disable-tsaware
2663           The image is Terminal Server aware.  This option is disabled by
2664           default.
2665
2666       --insert-timestamp
2667       --no-insert-timestamp
2668           Insert a real timestamp into the image.  This is the default
2669           behaviour as it matches legacy code and it means that the image
2670           will work with other, proprietary tools.  The problem with this
2671           default is that it will result in slightly different images being
2672           produced each time the same sources are linked.  The option
2673           --no-insert-timestamp can be used to insert a zero value for the
2674           timestamp, this ensuring that binaries produced from identical
2675           sources will compare identically.
2676
2677       --enable-reloc-section
2678       --disable-reloc-section
2679           Create the base relocation table, which is necessary if the image
2680           is loaded at a different image base than specified in the PE
2681           header.  This option is enabled by default.
2682
2683       The C6X uClinux target uses a binary format called DSBT to support
2684       shared libraries.  Each shared library in the system needs to have a
2685       unique index; all executables use an index of 0.
2686
2687       --dsbt-size size
2688           This option sets the number of entries in the DSBT of the current
2689           executable or shared library to size.  The default is to create a
2690           table with 64 entries.
2691
2692       --dsbt-index index
2693           This option sets the DSBT index of the current executable or shared
2694           library to index.  The default is 0, which is appropriate for
2695           generating executables.  If a shared library is generated with a
2696           DSBT index of 0, the "R_C6000_DSBT_INDEX" relocs are copied into
2697           the output file.
2698
2699           The --no-merge-exidx-entries switch disables the merging of
2700           adjacent exidx entries in frame unwind info.
2701
2702       --branch-stub
2703           This option enables linker branch relaxation by inserting branch
2704           stub sections when needed to extend the range of branches.  This
2705           option is usually not required since C-SKY supports branch and call
2706           instructions that can access the full memory range and branch
2707           relaxation is normally handled by the compiler or assembler.
2708
2709       --stub-group-size=N
2710           This option allows finer control of linker branch stub creation.
2711           It sets the maximum size of a group of input sections that can be
2712           handled by one stub section.  A negative value of N locates stub
2713           sections after their branches, while a positive value allows stub
2714           sections to appear either before or after the branches.  Values of
2715           1 or -1 indicate that the linker should choose suitable defaults.
2716
2717       The 68HC11 and 68HC12 linkers support specific options to control the
2718       memory bank switching mapping and trampoline code generation.
2719
2720       --no-trampoline
2721           This option disables the generation of trampoline. By default a
2722           trampoline is generated for each far function which is called using
2723           a "jsr" instruction (this happens when a pointer to a far function
2724           is taken).
2725
2726       --bank-window name
2727           This option indicates to the linker the name of the memory region
2728           in the MEMORY specification that describes the memory bank window.
2729           The definition of such region is then used by the linker to compute
2730           paging and addresses within the memory window.
2731
2732       The following options are supported to control handling of GOT
2733       generation when linking for 68K targets.
2734
2735       --got=type
2736           This option tells the linker which GOT generation scheme to use.
2737           type should be one of single, negative, multigot or target.  For
2738           more information refer to the Info entry for ld.
2739
2740       The following options are supported to control microMIPS instruction
2741       generation and branch relocation checks for ISA mode transitions when
2742       linking for MIPS targets.
2743
2744       --insn32
2745       --no-insn32
2746           These options control the choice of microMIPS instructions used in
2747           code generated by the linker, such as that in the PLT or lazy
2748           binding stubs, or in relaxation.  If --insn32 is used, then the
2749           linker only uses 32-bit instruction encodings.  By default or if
2750           --no-insn32 is used, all instruction encodings are used, including
2751           16-bit ones where possible.
2752
2753       --ignore-branch-isa
2754       --no-ignore-branch-isa
2755           These options control branch relocation checks for invalid ISA mode
2756           transitions.  If --ignore-branch-isa is used, then the linker
2757           accepts any branch relocations and any ISA mode transition required
2758           is lost in relocation calculation, except for some cases of "BAL"
2759           instructions which meet relaxation conditions and are converted to
2760           equivalent "JALX" instructions as the associated relocation is
2761           calculated.  By default or if --no-ignore-branch-isa is used a
2762           check is made causing the loss of an ISA mode transition to produce
2763           an error.
2764
2765       --compact-branches
2766       --no-compact-branches
2767           These options control the generation of compact instructions by the
2768           linker in the PLT entries for MIPS R6.
2769
2770       For the pdp11-aout target, three variants of the output format can be
2771       produced as selected by the following options.  The default variant for
2772       pdp11-aout is the --omagic option, whereas for other targets --nmagic
2773       is the default.  The --imagic option is defined only for the pdp11-aout
2774       target, while the others are described here as they apply to the
2775       pdp11-aout target.
2776
2777       -N
2778       --omagic
2779           Mark the output as "OMAGIC" (0407) in the a.out header to indicate
2780           that the text segment is not to be write-protected and shared.
2781           Since the text and data sections are both readable and writable,
2782           the data section is allocated immediately contiguous after the text
2783           segment.  This is the oldest format for PDP11 executable programs
2784           and is the default for ld on PDP11 Unix systems from the beginning
2785           through 2.11BSD.
2786
2787       -n
2788       --nmagic
2789           Mark the output as "NMAGIC" (0410) in the a.out header to indicate
2790           that when the output file is executed, the text portion will be
2791           read-only and shareable among all processes executing the same
2792           file.  This involves moving the data areas up to the first possible
2793           8K byte page boundary following the end of the text.  This option
2794           creates a pure executable format.
2795
2796       -z
2797       --imagic
2798           Mark the output as "IMAGIC" (0411) in the a.out header to indicate
2799           that when the output file is executed, the program text and data
2800           areas will be loaded into separate address spaces using the split
2801           instruction and data space feature of the memory management unit in
2802           larger models of the PDP11.  This doubles the address space
2803           available to the program.  The text segment is again pure, write-
2804           protected, and shareable.  The only difference in the output format
2805           between this option and the others, besides the magic number, is
2806           that both the text and data sections start at location 0.  The -z
2807           option selected this format in 2.11BSD.  This option creates a
2808           separate executable format.
2809
2810       --no-omagic
2811           Equivalent to --nmagic for pdp11-aout.
2812

ENVIRONMENT

2814       You can change the behaviour of ld with the environment variables
2815       "GNUTARGET", "LDEMULATION" and "COLLECT_NO_DEMANGLE".
2816
2817       "GNUTARGET" determines the input-file object format if you don't use -b
2818       (or its synonym --format).  Its value should be one of the BFD names
2819       for an input format.  If there is no "GNUTARGET" in the environment, ld
2820       uses the natural format of the target. If "GNUTARGET" is set to
2821       "default" then BFD attempts to discover the input format by examining
2822       binary input files; this method often succeeds, but there are potential
2823       ambiguities, since there is no method of ensuring that the magic number
2824       used to specify object-file formats is unique.  However, the
2825       configuration procedure for BFD on each system places the conventional
2826       format for that system first in the search-list, so ambiguities are
2827       resolved in favor of convention.
2828
2829       "LDEMULATION" determines the default emulation if you don't use the -m
2830       option.  The emulation can affect various aspects of linker behaviour,
2831       particularly the default linker script.  You can list the available
2832       emulations with the --verbose or -V options.  If the -m option is not
2833       used, and the "LDEMULATION" environment variable is not defined, the
2834       default emulation depends upon how the linker was configured.
2835
2836       Normally, the linker will default to demangling symbols.  However, if
2837       "COLLECT_NO_DEMANGLE" is set in the environment, then it will default
2838       to not demangling symbols.  This environment variable is used in a
2839       similar fashion by the "gcc" linker wrapper program.  The default may
2840       be overridden by the --demangle and --no-demangle options.
2841

SEE ALSO

2843       ar(1), nm(1), objcopy(1), objdump(1), readelf(1) and the Info entries
2844       for binutils and ld.
2845
2847       Copyright (c) 1991-2021 Free Software Foundation, Inc.
2848
2849       Permission is granted to copy, distribute and/or modify this document
2850       under the terms of the GNU Free Documentation License, Version 1.3 or
2851       any later version published by the Free Software Foundation; with no
2852       Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
2853       Texts.  A copy of the license is included in the section entitled "GNU
2854       Free Documentation License".
2855
2856
2857
2858binutils-2.37                     2022-03-10                             LD(1)
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