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431e1e85 | 1 | .\" Copyright (c) 1991, 92, 93, 94, 95, 1996 Free Software Foundation |
0e166a63 RP |
2 | .\" See section COPYING for conditions for redistribution |
3 | .TH ld 1 "17 August 1992" "cygnus support" "GNU Development Tools" | |
4 | .de BP | |
5 | .sp | |
6 | .ti \-.2i | |
7 | \(** | |
8 | .. | |
9 | ||
10 | .SH NAME | |
11 | ld \- the GNU linker | |
12 | ||
13 | .SH SYNOPSIS | |
14 | .hy 0 | |
15 | .na | |
16 | .TP | |
17 | .B ld | |
18 | .RB "[\|" \-o " | |
19 | .I output\c | |
20 | \&\|] \c | |
8ddef552 | 21 | .I objfile\c |
0e166a63 RP |
22 | \&.\|.\|. |
23 | .br | |
24 | .RB "[\|" \-A\c | |
25 | .I architecture\c | |
26 | \&\|] | |
27 | .RB "[\|" "\-b\ "\c | |
28 | .I input-format\c | |
29 | \&\|] | |
30 | .RB "[\|" \-Bstatic "\|]" | |
4551e108 ILT |
31 | .RB "[\|" \-Bdynamic "\|]" |
32 | .RB "[\|" \-Bsymbolic "\|]" | |
0e166a63 RP |
33 | .RB "[\|" "\-c\ "\c |
34 | .I commandfile\c | |
35 | \&\|] | |
36 | .RB "[\|" \-d | \-dc | \-dp\c | |
37 | \|] | |
38 | .br | |
39 | .RB "[\|" "\-defsym\ "\c | |
40 | .I symbol\c | |
41 | \& = \c | |
42 | .I expression\c | |
43 | \&\|] | |
44 | .RB "[\|" "\-e\ "\c | |
45 | .I entry\c | |
46 | \&\|] | |
39a6e282 | 47 | .RB "[\|" \-embedded\-relocs "\|]" |
4bdd9722 | 48 | .RB "[\|" \-export\-dynamic "\|]" |
0e166a63 RP |
49 | .RB "[\|" \-F "\|]" |
50 | .RB "[\|" "\-F\ "\c | |
51 | .I format\c | |
52 | \&\|] | |
53 | .RB "[\|" "\-format\ "\c | |
54 | .I input-format\c | |
55 | \&\|] | |
56 | .RB "[\|" \-g "\|]" | |
80165535 | 57 | .RB "[\|" \-G |
8ddef552 DM |
58 | .I size\c |
59 | \&\|] | |
bf065bfd | 60 | .RB "[\|" \-\-help "\|]" |
0e166a63 RP |
61 | .RB "[\|" \-i "\|]" |
62 | .RB "[\|" \-l\c | |
63 | .I ar\c | |
64 | \&\|] | |
65 | .RB "[\|" \-L\c | |
66 | .I searchdir\c | |
67 | \&\|] | |
8ddef552 | 68 | .RB "[\|" \-M "\|]" |
80165535 | 69 | .RB "[\|" \-Map |
d18a4527 DM |
70 | .I mapfile\c |
71 | \&\|] | |
80165535 | 72 | .RB "[\|" \-m |
8ddef552 DM |
73 | .I emulation\c |
74 | \&\|] | |
0e166a63 RP |
75 | .RB "[\|" \-n | \-N "\|]" |
76 | .RB "[\|" \-noinhibit-exec "\|]" | |
e920526d | 77 | .RB "[\|" \-no\-keep\-memory "\|]" |
346535cc DM |
78 | .RB "[\|" "\-oformat\ "\c |
79 | .I output-format\c | |
80 | \&\|] | |
0e166a63 RP |
81 | .RB "[\|" "\-R\ "\c |
82 | .I filename\c | |
83 | \&\|] | |
84 | .RB "[\|" \-relax "\|]" | |
85 | .RB "[\|" \-r | \-Ur "\|]" | |
5caef232 ILT |
86 | .RB "[\|" "\-rpath\ "\c |
87 | .I directory\c | |
88 | \&\|] | |
89 | .RB "[\|" "\-rpath\-link\ "\c | |
90 | .I directory\c | |
91 | \&\|] | |
0e166a63 RP |
92 | .RB "[\|" \-S "\|]" |
93 | .RB "[\|" \-s "\|]" | |
4551e108 | 94 | .RB "[\|" \-shared "\|]" |
2a28d8b0 | 95 | .RB "[\|" \-sort\-common "\|]" |
80165535 | 96 | .RB "[\|" "\-split\-by\-reloc\ "\c |
ec586565 ILT |
97 | .I count\c |
98 | \&\|] | |
99 | .RB "[\|" \-split\-by\-file "\|]" | |
0e166a63 RP |
100 | .RB "[\|" "\-T\ "\c |
101 | .I commandfile\c | |
102 | \&\|] | |
103 | .RB "[\|" "\-Ttext\ "\c | |
104 | .I textorg\c | |
105 | \&\|] | |
106 | .RB "[\|" "\-Tdata\ "\c | |
107 | .I dataorg\c | |
108 | \&\|] | |
109 | .RB "[\|" "\-Tbss\ "\c | |
110 | .I bssorg\c | |
111 | \&\|] | |
112 | .RB "[\|" \-t "\|]" | |
113 | .RB "[\|" "\-u\ "\c | |
114 | .I sym\c | |
115 | \&] | |
8ddef552 | 116 | .RB "[\|" \-V "\|]" |
0e166a63 | 117 | .RB "[\|" \-v "\|]" |
a82ae15d | 118 | .RB "[\|" \-\-verbose "\|]" |
bf065bfd | 119 | .RB "[\|" \-\-version "\|]" |
2a28d8b0 | 120 | .RB "[\|" \-warn\-common "\|]" |
a89d9f5b | 121 | .RB "[\|" \-warn\-constructors "\|]" |
4b7d2399 | 122 | .RB "[\|" \-warn\-multiple\-gp "\|]" |
809ee7e0 | 123 | .RB "[\|" \-warn\-once "\|]" |
ee499d81 | 124 | .RB "[\|" \-\-whole\-archive "\|]" |
3c8deccc | 125 | .RB "[\|" \-\-no\-whole\-archive "\|]" |
e3d73386 ILT |
126 | .RB "[\|" "\-\-wrap\ "\c |
127 | .I symbol\c | |
128 | \&\|] | |
0e166a63 RP |
129 | .RB "[\|" \-X "\|]" |
130 | .RB "[\|" \-x "\|]" | |
0e166a63 RP |
131 | .ad b |
132 | .hy 1 | |
133 | .SH DESCRIPTION | |
134 | \c | |
135 | .B ld\c | |
136 | \& combines a number of object and archive files, relocates | |
137 | their data and ties up symbol references. Often the last step in | |
138 | building a new compiled program to run is a call to \c | |
139 | .B ld\c | |
140 | \&. | |
141 | ||
142 | \c | |
143 | .B ld\c | |
144 | \& accepts Linker Command Language files | |
145 | to provide explicit and total control over the linking process. | |
146 | This man page does not describe the command language; see the `\|\c | |
147 | .B ld\c | |
148 | \|' entry in `\|\c | |
149 | .B info\c | |
150 | \|', or the manual | |
151 | .I | |
152 | ld: the GNU linker | |
153 | \&, for full details on the command language and on other aspects of | |
154 | the GNU linker. | |
155 | ||
156 | This version of \c | |
157 | .B ld\c | |
158 | \& uses the general purpose BFD libraries | |
159 | to operate on object files. This allows \c | |
160 | .B ld\c | |
161 | \& to read, combine, and | |
162 | write object files in many different formats\(em\&for example, COFF or | |
163 | \c | |
164 | .B a.out\c | |
165 | \&. Different formats may be linked together to produce any | |
166 | available kind of object file. You can use `\|\c | |
167 | .B objdump \-i\c | |
168 | \|' to get a list of formats supported on various architectures; see | |
169 | .BR objdump ( 1 ). | |
170 | ||
171 | Aside from its flexibility, the GNU linker is more helpful than other | |
172 | linkers in providing diagnostic information. Many linkers abandon | |
173 | execution immediately upon encountering an error; whenever possible, | |
174 | \c | |
175 | .B ld\c | |
176 | \& continues executing, allowing you to identify other errors | |
177 | (or, in some cases, to get an output file in spite of the error). | |
178 | ||
179 | The GNU linker \c | |
180 | .B ld\c | |
181 | \& is meant to cover a broad range of situations, | |
182 | and to be as compatible as possible with other linkers. As a result, | |
183 | you have many choices to control its behavior through the command line, | |
184 | and through environment variables. | |
185 | ||
186 | .SH OPTIONS | |
187 | The plethora of command-line options may seem intimidating, but in | |
188 | actual practice few of them are used in any particular context. | |
189 | For instance, a frequent use of \c | |
190 | .B ld\c | |
191 | \& is to link standard Unix | |
192 | object files on a standard, supported Unix system. On such a system, to | |
193 | link a file \c | |
194 | .B hello.o\c | |
195 | \&: | |
196 | .sp | |
197 | .br | |
198 | $\ ld\ \-o\ output\ /lib/crt0.o\ hello.o\ \-lc | |
199 | .br | |
200 | .sp | |
201 | This tells \c | |
202 | .B ld\c | |
203 | \& to produce a file called \c | |
204 | .B output\c | |
205 | \& as the | |
206 | result of linking the file \c | |
207 | .B /lib/crt0.o\c | |
208 | \& with \c | |
209 | .B hello.o\c | |
210 | \& and | |
211 | the library \c | |
212 | .B libc.a\c | |
213 | \& which will come from the standard search | |
214 | directories. | |
215 | ||
216 | The command-line options to \c | |
217 | .B ld\c | |
218 | \& may be specified in any order, and | |
219 | may be repeated at will. For the most part, repeating an option with a | |
220 | different argument will either have no further effect, or override prior | |
221 | occurrences (those further to the left on the command line) of an | |
222 | option. | |
223 | ||
224 | The exceptions\(em\&which may meaningfully be used more than once\(em\&are | |
225 | \c | |
226 | .B \-A\c | |
227 | \&, \c | |
228 | .B \-b\c | |
229 | \& (or its synonym \c | |
230 | .B \-format\c | |
231 | \&), \c | |
232 | .B \-defsym\c | |
233 | \&, | |
234 | \c | |
235 | .B \-L\c | |
236 | \&, \c | |
237 | .B \-l\c | |
238 | \&, \c | |
239 | .B \-R\c | |
240 | \&, and \c | |
241 | .B \-u\c | |
242 | \&. | |
243 | ||
244 | The list of object files to be linked together, shown as \c | |
8ddef552 | 245 | .I objfile\c |
0e166a63 RP |
246 | \&, |
247 | may follow, precede, or be mixed in with command-line options; save that | |
248 | an \c | |
8ddef552 | 249 | .I objfile\c |
0e166a63 RP |
250 | \& argument may not be placed between an option flag and |
251 | its argument. | |
252 | ||
253 | Usually the linker is invoked with at least one object file, but other | |
254 | forms of binary input files can also be specified with \c | |
255 | .B \-l\c | |
256 | \&, | |
257 | \c | |
258 | .B \-R\c | |
259 | \&, and the script command language. If \c | |
260 | .I no\c | |
261 | \& binary input | |
262 | files at all are specified, the linker does not produce any output, and | |
263 | issues the message `\|\c | |
264 | .B No input files\c | |
265 | \|'. | |
266 | ||
267 | Option arguments must either follow the option letter without intervening | |
268 | whitespace, or be given as separate arguments immediately following the | |
269 | option that requires them. | |
270 | ||
0e166a63 | 271 | .TP |
80165535 | 272 | .BI "-A" "architecture" |
0e166a63 RP |
273 | In the current release of \c |
274 | .B ld\c | |
275 | \&, this option is useful only for the | |
276 | Intel 960 family of architectures. In that \c | |
277 | .B ld\c | |
278 | \& configuration, the | |
279 | \c | |
280 | .I architecture\c | |
281 | \& argument is one of the two-letter names identifying | |
282 | members of the 960 family; the option specifies the desired output | |
283 | target, and warns of any incompatible instructions in the input files. | |
284 | It also modifies the linker's search strategy for archive libraries, to | |
285 | support the use of libraries specific to each particular | |
286 | architecture, by including in the search loop names suffixed with the | |
287 | string identifying the architecture. | |
288 | ||
289 | For example, if your \c | |
290 | .B ld\c | |
291 | \& command line included `\|\c | |
292 | .B \-ACA\c | |
293 | \|' as | |
294 | well as `\|\c | |
295 | .B \-ltry\c | |
296 | \|', the linker would look (in its built-in search | |
297 | paths, and in any paths you specify with \c | |
298 | .B \-L\c | |
299 | \&) for a library with | |
300 | the names | |
301 | .sp | |
302 | .br | |
303 | try | |
304 | .br | |
305 | libtry.a | |
306 | .br | |
307 | tryca | |
308 | .br | |
309 | libtryca.a | |
310 | .br | |
311 | .sp | |
312 | ||
313 | The first two possibilities would be considered in any event; the last | |
314 | two are due to the use of `\|\c | |
315 | .B \-ACA\c | |
316 | \|'. | |
317 | ||
318 | Future releases of \c | |
319 | .B ld\c | |
320 | \& may support similar functionality for | |
321 | other architecture families. | |
322 | ||
323 | You can meaningfully use \c | |
324 | .B \-A\c | |
325 | \& more than once on a command line, if | |
326 | an architecture family allows combination of target architectures; each | |
327 | use will add another pair of name variants to search for when \c | |
80165535 | 328 | .B \-l |
0e166a63 RP |
329 | specifies a library. |
330 | ||
331 | .TP | |
80165535 | 332 | .BI "\-b " "input-format" |
0e166a63 RP |
333 | Specify the binary format for input object files that follow this option |
334 | on the command line. You don't usually need to specify this, as | |
335 | \c | |
336 | .B ld\c | |
337 | \& is configured to expect as a default input format the most | |
338 | usual format on each machine. \c | |
339 | .I input-format\c | |
340 | \& is a text string, the | |
341 | name of a particular format supported by the BFD libraries. | |
342 | \c | |
343 | .B \-format \c | |
344 | .I input-format\c | |
345 | \&\c | |
346535cc DM |
346 | \& has the same effect, as does the script command |
347 | .BR TARGET . | |
0e166a63 RP |
348 | |
349 | You may want to use this option if you are linking files with an unusual | |
350 | binary format. You can also use \c | |
351 | .B \-b\c | |
352 | \& to switch formats explicitly (when | |
353 | linking object files of different formats), by including | |
354 | \c | |
355 | .B \-b \c | |
356 | .I input-format\c | |
357 | \&\c | |
358 | \& before each group of object files in a | |
359 | particular format. | |
360 | ||
361 | The default format is taken from the environment variable | |
362 | .B GNUTARGET\c | |
363 | \&. You can also define the input | |
364 | format from a script, using the command \c | |
365 | .B TARGET\c | |
366 | \&. | |
367 | ||
368 | .TP | |
369 | .B \-Bstatic | |
4551e108 ILT |
370 | Do not link against shared libraries. This is only meaningful on |
371 | platforms for which shared libraries are supported. | |
372 | ||
373 | .TP | |
374 | .B \-Bdynamic | |
375 | Link against dynamic libraries. This is only meaningful on platforms | |
376 | for which shared libraries are supported. This option is normally the | |
377 | default on such platforms. | |
378 | ||
379 | .TP | |
380 | .B \-Bsymbolic | |
381 | When creating a shared library, bind references to global symbols to | |
382 | the definition within the shared library, if any. Normally, it is | |
383 | possible for a program linked against a shared library to override the | |
384 | definition within the shared library. This option is only meaningful | |
385 | on ELF platforms which support shared libraries. | |
0e166a63 RP |
386 | |
387 | .TP | |
80165535 | 388 | .BI "\-c " "commandfile" |
0e166a63 RP |
389 | Directs \c |
390 | .B ld\c | |
391 | \& to read link commands from the file | |
392 | \c | |
393 | .I commandfile\c | |
394 | \&. These commands will completely override \c | |
395 | .B ld\c | |
396 | \&'s | |
397 | default link format (rather than adding to it); \c | |
398 | .I commandfile\c | |
399 | \& must | |
400 | specify everything necessary to describe the target format. | |
401 | ||
402 | ||
403 | You may also include a script of link commands directly in the command | |
404 | line by bracketing it between `\|\c | |
405 | .B {\c | |
406 | \|' and `\|\c | |
407 | .B }\c | |
408 | \|' characters. | |
409 | ||
410 | .TP | |
411 | .B \-d | |
412 | .TP | |
413 | .B \-dc | |
414 | .TP | |
415 | .B \-dp | |
416 | These three options are equivalent; multiple forms are supported for | |
417 | compatibility with other linkers. Use any of them to make \c | |
80165535 | 418 | .B ld |
0e166a63 RP |
419 | assign space to common symbols even if a relocatable output file is |
420 | specified (\c | |
421 | .B \-r\c | |
422 | \&). The script command | |
423 | \c | |
424 | .B FORCE_COMMON_ALLOCATION\c | |
425 | \& has the same effect. | |
426 | ||
427 | .TP | |
80165535 | 428 | .BI "-defsym " "symbol" "\fR = \fP" expression |
0e166a63 RP |
429 | Create a global symbol in the output file, containing the absolute |
430 | address given by \c | |
431 | .I expression\c | |
432 | \&. You may use this option as many | |
433 | times as necessary to define multiple symbols in the command line. A | |
434 | limited form of arithmetic is supported for the \c | |
435 | .I expression\c | |
436 | \& in this | |
437 | context: you may give a hexadecimal constant or the name of an existing | |
438 | symbol, or use \c | |
439 | .B +\c | |
440 | \& and \c | |
441 | .B \-\c | |
442 | \& to add or subtract hexadecimal | |
443 | constants or symbols. If you need more elaborate expressions, consider | |
444 | using the linker command language from a script. | |
445 | ||
446 | .TP | |
447 | .BI "-e " "entry"\c | |
448 | \& | |
449 | Use \c | |
450 | .I entry\c | |
451 | \& as the explicit symbol for beginning execution of your | |
452 | program, rather than the default entry point. for a | |
453 | discussion of defaults and other ways of specifying the | |
454 | entry point. | |
455 | ||
39a6e282 ILT |
456 | .TP |
457 | .B \-embedded\-relocs | |
458 | This option is only meaningful when linking MIPS embedded PIC code, | |
459 | generated by the | |
460 | .B \-membedded\-pic | |
461 | option to the GNU compiler and assembler. It causes the linker to | |
462 | create a table which may be used at runtime to relocate any data which | |
463 | was statically initialized to pointer values. See the code in | |
464 | testsuite/ld-empic for details. | |
465 | ||
4bdd9722 ILT |
466 | .TP |
467 | .B \-export\-dynamic | |
468 | When creating an ELF file, add all symbols to the dynamic symbol table. | |
469 | Normally, the dynamic symbol table contains only symbols which are used | |
470 | by a dynamic object. This option is needed for some uses of | |
471 | .I dlopen. | |
472 | ||
0e166a63 RP |
473 | .TP |
474 | .B \-F | |
475 | .TP | |
80165535 | 476 | .BI "-F" "format" |
0e166a63 RP |
477 | Some older linkers used this option throughout a compilation toolchain |
478 | for specifying object-file format for both input and output object | |
479 | files. \c | |
480 | .B ld\c | |
481 | \&'s mechanisms (the \c | |
482 | .B \-b\c | |
483 | \& or \c | |
484 | .B \-format\c | |
485 | \& options | |
486 | for input files, the \c | |
487 | .B TARGET\c | |
488 | \& command in linker scripts for output | |
489 | files, the \c | |
490 | .B GNUTARGET\c | |
491 | \& environment variable) are more flexible, but | |
492 | but it accepts (and ignores) the \c | |
493 | .B \-F\c | |
494 | \& option flag for compatibility | |
495 | with scripts written to call the old linker. | |
496 | ||
497 | .TP | |
80165535 | 498 | .BI "\-format " "input\-format" |
0e166a63 RP |
499 | Synonym for \c |
500 | .B \-b\c | |
501 | \& \c | |
2a28d8b0 | 502 | .I input\-format\c |
0e166a63 RP |
503 | \&. |
504 | ||
505 | .TP | |
506 | .B \-g | |
507 | Accepted, but ignored; provided for compatibility with other tools. | |
508 | ||
8ddef552 DM |
509 | .TP |
510 | .BI "\-G " "size"\c | |
511 | Set the maximum size of objects to be optimized using the GP register | |
512 | to | |
513 | .I size | |
514 | under MIPS ECOFF. Ignored for other object file formats. | |
515 | ||
bf065bfd DM |
516 | .TP |
517 | .B \-\-help | |
518 | Print a summary of the command-line options on the standard output and exit. | |
519 | This option and | |
520 | .B \-\-version | |
521 | begin with two dashes instead of one | |
522 | for compatibility with other GNU programs. The other options start with | |
523 | only one dash for compatibility with other linkers. | |
524 | ||
0e166a63 RP |
525 | .TP |
526 | .B \-i | |
527 | Perform an incremental link (same as option \c | |
528 | .B \-r\c | |
529 | \&). | |
530 | ||
531 | .TP | |
2a28d8b0 | 532 | .BI "\-l" "ar"\c |
0e166a63 RP |
533 | \& |
534 | Add an archive file \c | |
535 | .I ar\c | |
536 | \& to the list of files to link. This | |
537 | option may be used any number of times. \c | |
538 | .B ld\c | |
539 | \& will search its | |
540 | path-list for occurrences of \c | |
541 | .B lib\c | |
542 | .I ar\c | |
543 | \&.a\c | |
544 | \& for every \c | |
80165535 | 545 | .I ar |
0e166a63 RP |
546 | specified. |
547 | ||
548 | .TP | |
80165535 | 549 | .BI "\-L" "searchdir" |
0e166a63 RP |
550 | This command adds path \c |
551 | .I searchdir\c | |
552 | \& to the list of paths that | |
553 | \c | |
554 | .B ld\c | |
555 | \& will search for archive libraries. You may use this option | |
556 | any number of times. | |
557 | ||
558 | The default set of paths searched (without being specified with | |
559 | \c | |
560 | .B \-L\c | |
561 | \&) depends on what emulation mode \c | |
562 | .B ld\c | |
563 | \& is using, and in | |
564 | some cases also on how it was configured. The | |
565 | paths can also be specified in a link script with the \c | |
80165535 | 566 | .B SEARCH_DIR |
0e166a63 RP |
567 | command. |
568 | ||
569 | .TP | |
570 | .B \-M | |
0e166a63 RP |
571 | Print (to the standard output file) a link map\(em\&diagnostic information |
572 | about where symbols are mapped by \c | |
573 | .B ld\c | |
574 | \&, and information on global | |
575 | common storage allocation. | |
576 | ||
d18a4527 DM |
577 | .TP |
578 | .BI "\-Map " "mapfile"\c | |
579 | Print to the file | |
580 | .I mapfile | |
581 | a link map\(em\&diagnostic information | |
582 | about where symbols are mapped by \c | |
583 | .B ld\c | |
584 | \&, and information on global | |
585 | common storage allocation. | |
586 | ||
8ddef552 DM |
587 | .TP |
588 | .BI "\-m " "emulation"\c | |
589 | Emulate the | |
590 | .I emulation | |
591 | linker. You can list the available emulations with the | |
a82ae15d | 592 | .I \-\-verbose |
1f59c7a7 ILT |
593 | or |
594 | .I \-V | |
595 | options. This option overrides the compiled-in default, which is the | |
8ddef552 DM |
596 | system for which you configured |
597 | .BR ld . | |
598 | ||
0e166a63 RP |
599 | .TP |
600 | .B \-N | |
601 | specifies readable and writable \c | |
602 | .B text\c | |
603 | \& and \c | |
604 | .B data\c | |
605 | \& sections. If | |
606 | the output format supports Unix style magic numbers, the output is | |
607 | marked as \c | |
608 | .B OMAGIC\c | |
609 | \&. | |
610 | ||
611 | When you use the `\|\c | |
612 | .B \-N\c | |
613 | \&\|' option, the linker does not page-align the | |
614 | data segment. | |
615 | ||
616 | .TP | |
617 | .B \-n | |
618 | sets the text segment to be read only, and \c | |
619 | .B NMAGIC\c | |
620 | \& is written | |
621 | if possible. | |
622 | ||
623 | .TP | |
2a28d8b0 | 624 | .B \-noinhibit\-exec |
0e166a63 RP |
625 | Normally, the linker will not produce an output file if it encounters |
626 | errors during the link process. With this flag, you can specify that | |
627 | you wish the output file retained even after non-fatal errors. | |
628 | ||
e920526d ILT |
629 | .TP |
630 | .B \-no\-keep\-memory | |
631 | The linker normally optimizes for speed over memory usage by caching | |
632 | the symbol tables of input files in memory. This option tells the | |
633 | linker to instead optimize for memory usage, by rereading the symbol | |
634 | tables as necessary. This may be required if the linker runs out of | |
635 | memory space while linking a large executable. | |
636 | ||
0e166a63 | 637 | .TP |
80165535 | 638 | .BI "\-o " "output" |
0e166a63 RP |
639 | .I output\c |
640 | \& is a name for the program produced by \c | |
641 | .B ld\c | |
642 | \&; if this | |
643 | option is not specified, the name `\|\c | |
644 | .B a.out\c | |
645 | \|' is used by default. The | |
646 | script command \c | |
647 | .B OUTPUT\c | |
648 | \& can also specify the output file name. | |
649 | ||
346535cc | 650 | .TP |
80165535 | 651 | .BI "\-oformat " "output\-format" |
346535cc DM |
652 | Specify the binary format for the output object file. |
653 | You don't usually need to specify this, as | |
654 | \c | |
655 | .B ld\c | |
656 | \& is configured to produce as a default output format the most | |
657 | usual format on each machine. \c | |
658 | .I output-format\c | |
659 | \& is a text string, the | |
660 | name of a particular format supported by the BFD libraries. | |
661 | The script command | |
662 | .B OUTPUT_FORMAT | |
663 | can also specify the output format, but this option overrides it. | |
664 | ||
0e166a63 | 665 | .TP |
80165535 | 666 | .BI "\-R " "filename" |
0e166a63 RP |
667 | Read symbol names and their addresses from \c |
668 | .I filename\c | |
669 | \&, but do not | |
670 | relocate it or include it in the output. This allows your output file | |
671 | to refer symbolically to absolute locations of memory defined in other | |
672 | programs. | |
673 | ||
674 | .TP | |
675 | .B \-relax | |
676 | An option with machine dependent effects. Currently this option is only | |
677 | supported on the H8/300. | |
678 | ||
679 | On some platforms, use this option to perform global optimizations that | |
680 | become possible when the linker resolves addressing in your program, such | |
681 | as relaxing address modes and synthesizing new instructions in the | |
682 | output object file. | |
683 | ||
684 | On platforms where this is not supported, `\|\c | |
685 | .B \-relax\c | |
686 | \&\|' is accepted, but has no effect. | |
687 | ||
688 | .TP | |
689 | .B \-r | |
690 | Generates relocatable output\(em\&i.e., generate an output file that can in | |
691 | turn serve as input to \c | |
692 | .B ld\c | |
693 | \&. This is often called \c | |
694 | .I partial | |
695 | linking\c | |
696 | \&. As a side effect, in environments that support standard Unix | |
697 | magic numbers, this option also sets the output file's magic number to | |
698 | \c | |
699 | .B OMAGIC\c | |
700 | \&. | |
701 | If this option is not specified, an absolute file is produced. When | |
702 | linking C++ programs, this option \c | |
703 | .I will not\c | |
704 | \& resolve references to | |
705 | constructors; \c | |
706 | .B \-Ur\c | |
707 | \& is an alternative. | |
708 | ||
709 | This option does the same as \c | |
710 | .B \-i\c | |
711 | \&. | |
712 | ||
5caef232 ILT |
713 | .TP |
714 | .B \-rpath\ \fIdirectory | |
715 | Add a directory to the runtime library search path. This is used when | |
716 | linking an ELF executable with shared objects. All | |
717 | .B \-rpath | |
718 | arguments are concatenated and passed to the runtime linker, which uses | |
719 | them to locate shared objects at runtime. The | |
720 | .B \-rpath | |
721 | option is also used when locating shared objects which are needed by | |
722 | shared objects explicitly included in the link; see the description of | |
723 | the | |
724 | .B \-rpath\-link | |
20406675 ILT |
725 | option. If |
726 | .B \-rpath | |
727 | is not used when linking an ELF executable, the contents of the | |
728 | environment variable | |
729 | .B LD_RUN_PATH | |
730 | will be used if it is defined. | |
5caef232 ILT |
731 | |
732 | The | |
733 | .B \-rpath | |
734 | option may also be used on SunOS. By default, on SunOS, the linker | |
735 | will form a runtime search patch out of all the | |
736 | .B \-L | |
737 | options it is given. If a | |
4bdd9722 ILT |
738 | .B \-rpath |
739 | option is used, the runtime search path will be formed exclusively | |
740 | using the | |
5caef232 ILT |
741 | .B \-rpath |
742 | options, ignoring | |
743 | the | |
744 | .B \-L | |
745 | options. This can be useful when using gcc, which adds many | |
746 | .B \-L | |
747 | options which may be on NFS mounted filesystems. | |
748 | ||
749 | .TP | |
750 | .B \-rpath\-link\ \fIdirectory | |
235c6a67 ILT |
751 | When using ELF or SunOS, one shared library may require another. This |
752 | happens when an | |
5caef232 ILT |
753 | .B ld\ \-shared |
754 | link includes a shared library as one of the input files. | |
755 | ||
756 | When the linker encounters such a dependency when doing a non-shared, | |
757 | non-relocateable link, it will automatically try to locate the required | |
758 | shared library and include it in the link, if it is not included | |
759 | explicitly. In such a case, the | |
760 | .B \-rpath\-link | |
761 | option specifies the first set of directories to search. The | |
762 | .B \-rpath\-link | |
763 | option may specify a sequence of directory names either by specifying | |
764 | a list of names separated by colons, or by appearing multiple times. | |
765 | ||
766 | If the required shared library is not found, the linker will issue a | |
767 | warning and continue with the link. | |
768 | ||
0e166a63 RP |
769 | .TP |
770 | .B \-S | |
771 | Omits debugger symbol information (but not all symbols) from the output file. | |
772 | ||
773 | .TP | |
774 | .B \-s | |
775 | Omits all symbol information from the output file. | |
776 | ||
4551e108 ILT |
777 | .TP |
778 | .B \-shared | |
235c6a67 ILT |
779 | Create a shared library. This is currently only supported on ELF and |
780 | SunOS platforms (on SunOS it is not required, as the linker will | |
781 | automatically create a shared library when there are undefined symbols | |
782 | and the | |
783 | .B \-e | |
784 | option is not used). | |
4551e108 | 785 | |
0e166a63 | 786 | .TP |
2a28d8b0 DM |
787 | .B \-sort\-common |
788 | Normally, when | |
789 | .B ld | |
790 | places the global common symbols in the appropriate output sections, | |
791 | it sorts them by size. First come all the one byte symbols, then all | |
792 | the two bytes, then all the four bytes, and then everything else. | |
da08e9b9 DM |
793 | This is to prevent gaps between symbols due to |
794 | alignment constraints. This option disables that sorting. | |
2a28d8b0 | 795 | |
ec586565 ILT |
796 | .TP |
797 | .B \-split\-by\-reloc\ \fIcount | |
798 | Trys to creates extra sections in the output file so that no single | |
799 | output section in the file contains more than | |
800 | .I count | |
801 | relocations. | |
802 | This is useful when generating huge relocatable for downloading into | |
803 | certain real time kernels with the COFF object file format; since COFF | |
804 | cannot represent more than 65535 relocations in a single section. | |
805 | Note that this will fail to work with object file formats which do not | |
806 | support arbitrary sections. The linker will not split up individual | |
807 | input sections for redistribution, so if a single input section | |
808 | contains more than | |
809 | .I count | |
810 | relocations one output section will contain that many relocations. | |
811 | ||
812 | .TP | |
813 | .B \-split\-by\-file | |
814 | Similar to | |
815 | .B \-split\-by\-reloc | |
816 | but creates a new output section for each input file. | |
817 | ||
2a28d8b0 DM |
818 | .TP |
819 | .BI "\-Tbss " "org"\c | |
0e166a63 | 820 | .TP |
2a28d8b0 | 821 | .BI "\-Tdata " "org"\c |
0e166a63 | 822 | .TP |
2a28d8b0 | 823 | .BI "\-Ttext " "org"\c |
0e166a63 RP |
824 | Use \c |
825 | .I org\c | |
826 | \& as the starting address for\(em\&respectively\(em\&the | |
827 | \c | |
828 | .B bss\c | |
829 | \&, \c | |
830 | .B data\c | |
831 | \&, or the \c | |
832 | .B text\c | |
833 | \& segment of the output file. | |
834 | \c | |
835 | .I textorg\c | |
836 | \& must be a hexadecimal integer. | |
837 | ||
838 | .TP | |
80165535 | 839 | .BI "\-T " "commandfile" |
0e166a63 RP |
840 | Equivalent to \c |
841 | .B \-c \c | |
842 | .I commandfile\c | |
843 | \&\c | |
844 | \&; supported for compatibility with | |
845 | other tools. | |
846 | ||
847 | .TP | |
848 | .B \-t | |
849 | Prints names of input files as \c | |
850 | .B ld\c | |
851 | \& processes them. | |
852 | ||
853 | .TP | |
2a28d8b0 | 854 | .BI "\-u " "sym" |
0e166a63 RP |
855 | Forces \c |
856 | .I sym\c | |
857 | \& to be entered in the output file as an undefined symbol. | |
858 | This may, for example, trigger linking of additional modules from | |
859 | standard libraries. \c | |
860 | .B \-u\c | |
861 | \& may be repeated with different option | |
862 | arguments to enter additional undefined symbols. | |
863 | ||
864 | .TP | |
865 | .B \-Ur | |
866 | For anything other than C++ programs, this option is equivalent to | |
867 | \c | |
868 | .B \-r\c | |
869 | \&: it generates relocatable output\(em\&i.e., an output file that can in | |
870 | turn serve as input to \c | |
871 | .B ld\c | |
872 | \&. When linking C++ programs, \c | |
80165535 | 873 | .B \-Ur |
0e166a63 RP |
874 | .I will\c |
875 | \& resolve references to constructors, unlike \c | |
876 | .B \-r\c | |
877 | \&. | |
878 | ||
8ddef552 | 879 | .TP |
a82ae15d | 880 | .B \-\-verbose |
8ddef552 DM |
881 | Display the version number for \c |
882 | .B ld | |
883 | and list the supported emulations. | |
de87cdb4 | 884 | Display which input files can and can not be opened. |
8ddef552 | 885 | |
0e166a63 | 886 | .TP |
a82ae15d | 887 | .B \-v, \-V |
0e166a63 RP |
888 | Display the version number for \c |
889 | .B ld\c | |
890 | \&. | |
1f59c7a7 ILT |
891 | The |
892 | .B \-V | |
893 | option also lists the supported emulations. | |
0e166a63 | 894 | |
bf065bfd DM |
895 | .TP |
896 | .B \-\-version | |
897 | Display the version number for \c | |
898 | .B ld | |
899 | and exit. | |
900 | ||
2a28d8b0 DM |
901 | .TP |
902 | .B \-warn\-common | |
903 | Warn when a common symbol is combined with another common symbol or with | |
904 | a symbol definition. Unix linkers allow this somewhat sloppy practice, | |
905 | but linkers on some other operating systems do not. This option allows | |
906 | you to find potential problems from combining global symbols. | |
907 | ||
a89d9f5b ILT |
908 | .TP |
909 | .B \-warn\-constructors | |
910 | Warn if any global constructors are used. This is only useful for a | |
911 | few object file formats. For formats like COFF or ELF, the linker can | |
912 | not detect the use of global constructors. | |
913 | ||
4b7d2399 ILT |
914 | .TP |
915 | .B \-warn\-multiple\-gp | |
916 | Warn if the output file requires multiple global-pointer values. This | |
917 | option is only meaningful for certain processors, such as the Alpha. | |
918 | ||
809ee7e0 ILT |
919 | .TP |
920 | .B \-warn\-once | |
921 | Only warn once for each undefined symbol, rather than once per module | |
922 | which refers to it. | |
923 | ||
ee499d81 ILT |
924 | .TP |
925 | .B \-\-whole\-archive | |
3c8deccc ILT |
926 | For each archive mentioned on the command line after the |
927 | .B \-\-whole\-archive | |
928 | option, include every object file in the archive in the link, rather | |
929 | than searching the archive for the required object files. This is | |
930 | normally used to turn an archive file into a shared library, forcing | |
931 | every object to be included in the resulting shared library. | |
932 | ||
933 | .TP | |
934 | .B \-\-no\-whole\-archive | |
935 | Turn off the effect of the | |
936 | .B \-\-whole\-archive | |
937 | option for archives which appear later on the command line. | |
ee499d81 | 938 | |
e3d73386 ILT |
939 | .TP |
940 | .BI "--wrap " "symbol" | |
941 | Use a wrapper function for | |
942 | .I symbol. | |
943 | Any undefined reference to | |
944 | .I symbol | |
945 | will be resolved to | |
946 | .BI "__wrap_" "symbol". | |
947 | Any undefined reference to | |
948 | .BI "__real_" "symbol" | |
949 | will be resolved to | |
950 | .I symbol. | |
951 | ||
0e166a63 RP |
952 | .TP |
953 | .B \-X | |
21a2f026 ILT |
954 | Delete all temporary local symbols. For most targets, this is all local |
955 | symbols whose names begin with `\|\c | |
0e166a63 RP |
956 | .B L\c |
957 | \|'. | |
958 | ||
959 | .TP | |
960 | .B \-x | |
21a2f026 | 961 | Delete all local symbols. |
0e166a63 RP |
962 | |
963 | .PP | |
964 | ||
965 | .SH ENVIRONMENT | |
966 | \c | |
8ddef552 | 967 | You can change the behavior of |
0e166a63 | 968 | .B ld\c |
8ddef552 | 969 | \& with the environment variable \c |
0e166a63 | 970 | .B GNUTARGET\c |
8ddef552 | 971 | \&. |
0e166a63 RP |
972 | |
973 | \c | |
974 | .B GNUTARGET\c | |
975 | \& determines the input-file object format if you don't | |
976 | use \c | |
977 | .B \-b\c | |
978 | \& (or its synonym \c | |
979 | .B \-format\c | |
980 | \&). Its value should be one | |
981 | of the BFD names for an input format. If there is no | |
982 | \c | |
983 | .B GNUTARGET\c | |
984 | \& in the environment, \c | |
985 | .B ld\c | |
986 | \& uses the natural format | |
987 | of the host. If \c | |
988 | .B GNUTARGET\c | |
989 | \& is set to \c | |
990 | .B default\c | |
991 | \& then BFD attempts to discover the | |
992 | input format by examining binary input files; this method often | |
993 | succeeds, but there are potential ambiguities, since there is no method | |
994 | of ensuring that the magic number used to flag object-file formats is | |
995 | unique. However, the configuration procedure for BFD on each system | |
996 | places the conventional format for that system first in the search-list, | |
997 | so ambiguities are resolved in favor of convention. | |
998 | ||
0e166a63 RP |
999 | .PP |
1000 | ||
1001 | .SH "SEE ALSO" | |
1002 | ||
1003 | .BR objdump ( 1 ) | |
1004 | .br | |
1005 | .br | |
1006 | .RB "`\|" ld "\|' and `\|" binutils "\|'" | |
1007 | entries in | |
1008 | .B info\c | |
1009 | .br | |
1010 | .I | |
1011 | ld: the GNU linker\c | |
1012 | , Steve Chamberlain and Roland Pesch; | |
1013 | .I | |
1014 | The GNU Binary Utilities\c | |
1015 | , Roland H. Pesch. | |
1016 | ||
1017 | .SH COPYING | |
1018 | Copyright (c) 1991, 1992 Free Software Foundation, Inc. | |
1019 | .PP | |
1020 | Permission is granted to make and distribute verbatim copies of | |
1021 | this manual provided the copyright notice and this permission notice | |
1022 | are preserved on all copies. | |
1023 | .PP | |
1024 | Permission is granted to copy and distribute modified versions of this | |
1025 | manual under the conditions for verbatim copying, provided that the | |
1026 | entire resulting derived work is distributed under the terms of a | |
1027 | permission notice identical to this one. | |
1028 | .PP | |
1029 | Permission is granted to copy and distribute translations of this | |
1030 | manual into another language, under the above conditions for modified | |
1031 | versions, except that this permission notice may be included in | |
1032 | translations approved by the Free Software Foundation instead of in | |
1033 | the original English. |