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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 "\|]" |
7ec9d825 | 48 | .RB "[\|" \-E "\|]" |
4bdd9722 | 49 | .RB "[\|" \-export\-dynamic "\|]" |
0e166a63 RP |
50 | .RB "[\|" \-F "\|]" |
51 | .RB "[\|" "\-F\ "\c | |
52 | .I format\c | |
53 | \&\|] | |
54 | .RB "[\|" "\-format\ "\c | |
55 | .I input-format\c | |
56 | \&\|] | |
57 | .RB "[\|" \-g "\|]" | |
80165535 | 58 | .RB "[\|" \-G |
8ddef552 DM |
59 | .I size\c |
60 | \&\|] | |
bf065bfd | 61 | .RB "[\|" \-\-help "\|]" |
0e166a63 RP |
62 | .RB "[\|" \-i "\|]" |
63 | .RB "[\|" \-l\c | |
64 | .I ar\c | |
65 | \&\|] | |
66 | .RB "[\|" \-L\c | |
67 | .I searchdir\c | |
68 | \&\|] | |
8ddef552 | 69 | .RB "[\|" \-M "\|]" |
80165535 | 70 | .RB "[\|" \-Map |
d18a4527 DM |
71 | .I mapfile\c |
72 | \&\|] | |
80165535 | 73 | .RB "[\|" \-m |
8ddef552 DM |
74 | .I emulation\c |
75 | \&\|] | |
0e166a63 RP |
76 | .RB "[\|" \-n | \-N "\|]" |
77 | .RB "[\|" \-noinhibit-exec "\|]" | |
e920526d | 78 | .RB "[\|" \-no\-keep\-memory "\|]" |
346535cc DM |
79 | .RB "[\|" "\-oformat\ "\c |
80 | .I output-format\c | |
81 | \&\|] | |
0e166a63 RP |
82 | .RB "[\|" "\-R\ "\c |
83 | .I filename\c | |
84 | \&\|] | |
85 | .RB "[\|" \-relax "\|]" | |
86 | .RB "[\|" \-r | \-Ur "\|]" | |
5caef232 ILT |
87 | .RB "[\|" "\-rpath\ "\c |
88 | .I directory\c | |
89 | \&\|] | |
90 | .RB "[\|" "\-rpath\-link\ "\c | |
91 | .I directory\c | |
92 | \&\|] | |
0e166a63 RP |
93 | .RB "[\|" \-S "\|]" |
94 | .RB "[\|" \-s "\|]" | |
4551e108 | 95 | .RB "[\|" \-shared "\|]" |
2a28d8b0 | 96 | .RB "[\|" \-sort\-common "\|]" |
80165535 | 97 | .RB "[\|" "\-split\-by\-reloc\ "\c |
ec586565 ILT |
98 | .I count\c |
99 | \&\|] | |
100 | .RB "[\|" \-split\-by\-file "\|]" | |
0e166a63 RP |
101 | .RB "[\|" "\-T\ "\c |
102 | .I commandfile\c | |
103 | \&\|] | |
104 | .RB "[\|" "\-Ttext\ "\c | |
105 | .I textorg\c | |
106 | \&\|] | |
107 | .RB "[\|" "\-Tdata\ "\c | |
108 | .I dataorg\c | |
109 | \&\|] | |
110 | .RB "[\|" "\-Tbss\ "\c | |
111 | .I bssorg\c | |
112 | \&\|] | |
113 | .RB "[\|" \-t "\|]" | |
114 | .RB "[\|" "\-u\ "\c | |
115 | .I sym\c | |
116 | \&] | |
8ddef552 | 117 | .RB "[\|" \-V "\|]" |
0e166a63 | 118 | .RB "[\|" \-v "\|]" |
a82ae15d | 119 | .RB "[\|" \-\-verbose "\|]" |
bf065bfd | 120 | .RB "[\|" \-\-version "\|]" |
2a28d8b0 | 121 | .RB "[\|" \-warn\-common "\|]" |
a89d9f5b | 122 | .RB "[\|" \-warn\-constructors "\|]" |
4b7d2399 | 123 | .RB "[\|" \-warn\-multiple\-gp "\|]" |
809ee7e0 | 124 | .RB "[\|" \-warn\-once "\|]" |
ee499d81 | 125 | .RB "[\|" \-\-whole\-archive "\|]" |
3c8deccc | 126 | .RB "[\|" \-\-no\-whole\-archive "\|]" |
e3d73386 ILT |
127 | .RB "[\|" "\-\-wrap\ "\c |
128 | .I symbol\c | |
129 | \&\|] | |
0e166a63 RP |
130 | .RB "[\|" \-X "\|]" |
131 | .RB "[\|" \-x "\|]" | |
0e166a63 RP |
132 | .ad b |
133 | .hy 1 | |
134 | .SH DESCRIPTION | |
135 | \c | |
136 | .B ld\c | |
137 | \& combines a number of object and archive files, relocates | |
138 | their data and ties up symbol references. Often the last step in | |
139 | building a new compiled program to run is a call to \c | |
140 | .B ld\c | |
141 | \&. | |
142 | ||
143 | \c | |
144 | .B ld\c | |
145 | \& accepts Linker Command Language files | |
146 | to provide explicit and total control over the linking process. | |
147 | This man page does not describe the command language; see the `\|\c | |
148 | .B ld\c | |
149 | \|' entry in `\|\c | |
150 | .B info\c | |
151 | \|', or the manual | |
152 | .I | |
153 | ld: the GNU linker | |
154 | \&, for full details on the command language and on other aspects of | |
155 | the GNU linker. | |
156 | ||
157 | This version of \c | |
158 | .B ld\c | |
159 | \& uses the general purpose BFD libraries | |
160 | to operate on object files. This allows \c | |
161 | .B ld\c | |
162 | \& to read, combine, and | |
163 | write object files in many different formats\(em\&for example, COFF or | |
164 | \c | |
165 | .B a.out\c | |
166 | \&. Different formats may be linked together to produce any | |
167 | available kind of object file. You can use `\|\c | |
168 | .B objdump \-i\c | |
169 | \|' to get a list of formats supported on various architectures; see | |
170 | .BR objdump ( 1 ). | |
171 | ||
172 | Aside from its flexibility, the GNU linker is more helpful than other | |
173 | linkers in providing diagnostic information. Many linkers abandon | |
174 | execution immediately upon encountering an error; whenever possible, | |
175 | \c | |
176 | .B ld\c | |
177 | \& continues executing, allowing you to identify other errors | |
178 | (or, in some cases, to get an output file in spite of the error). | |
179 | ||
180 | The GNU linker \c | |
181 | .B ld\c | |
182 | \& is meant to cover a broad range of situations, | |
183 | and to be as compatible as possible with other linkers. As a result, | |
184 | you have many choices to control its behavior through the command line, | |
185 | and through environment variables. | |
186 | ||
187 | .SH OPTIONS | |
188 | The plethora of command-line options may seem intimidating, but in | |
189 | actual practice few of them are used in any particular context. | |
190 | For instance, a frequent use of \c | |
191 | .B ld\c | |
192 | \& is to link standard Unix | |
193 | object files on a standard, supported Unix system. On such a system, to | |
194 | link a file \c | |
195 | .B hello.o\c | |
196 | \&: | |
197 | .sp | |
198 | .br | |
199 | $\ ld\ \-o\ output\ /lib/crt0.o\ hello.o\ \-lc | |
200 | .br | |
201 | .sp | |
202 | This tells \c | |
203 | .B ld\c | |
204 | \& to produce a file called \c | |
205 | .B output\c | |
206 | \& as the | |
207 | result of linking the file \c | |
208 | .B /lib/crt0.o\c | |
209 | \& with \c | |
210 | .B hello.o\c | |
211 | \& and | |
212 | the library \c | |
213 | .B libc.a\c | |
214 | \& which will come from the standard search | |
215 | directories. | |
216 | ||
217 | The command-line options to \c | |
218 | .B ld\c | |
219 | \& may be specified in any order, and | |
220 | may be repeated at will. For the most part, repeating an option with a | |
221 | different argument will either have no further effect, or override prior | |
222 | occurrences (those further to the left on the command line) of an | |
223 | option. | |
224 | ||
225 | The exceptions\(em\&which may meaningfully be used more than once\(em\&are | |
226 | \c | |
227 | .B \-A\c | |
228 | \&, \c | |
229 | .B \-b\c | |
230 | \& (or its synonym \c | |
231 | .B \-format\c | |
232 | \&), \c | |
233 | .B \-defsym\c | |
234 | \&, | |
235 | \c | |
236 | .B \-L\c | |
237 | \&, \c | |
238 | .B \-l\c | |
239 | \&, \c | |
240 | .B \-R\c | |
241 | \&, and \c | |
242 | .B \-u\c | |
243 | \&. | |
244 | ||
245 | The list of object files to be linked together, shown as \c | |
8ddef552 | 246 | .I objfile\c |
0e166a63 RP |
247 | \&, |
248 | may follow, precede, or be mixed in with command-line options; save that | |
249 | an \c | |
8ddef552 | 250 | .I objfile\c |
0e166a63 RP |
251 | \& argument may not be placed between an option flag and |
252 | its argument. | |
253 | ||
254 | Usually the linker is invoked with at least one object file, but other | |
255 | forms of binary input files can also be specified with \c | |
256 | .B \-l\c | |
257 | \&, | |
258 | \c | |
259 | .B \-R\c | |
260 | \&, and the script command language. If \c | |
261 | .I no\c | |
262 | \& binary input | |
263 | files at all are specified, the linker does not produce any output, and | |
264 | issues the message `\|\c | |
265 | .B No input files\c | |
266 | \|'. | |
267 | ||
268 | Option arguments must either follow the option letter without intervening | |
269 | whitespace, or be given as separate arguments immediately following the | |
270 | option that requires them. | |
271 | ||
0e166a63 | 272 | .TP |
80165535 | 273 | .BI "-A" "architecture" |
0e166a63 RP |
274 | In the current release of \c |
275 | .B ld\c | |
276 | \&, this option is useful only for the | |
277 | Intel 960 family of architectures. In that \c | |
278 | .B ld\c | |
279 | \& configuration, the | |
280 | \c | |
281 | .I architecture\c | |
282 | \& argument is one of the two-letter names identifying | |
283 | members of the 960 family; the option specifies the desired output | |
284 | target, and warns of any incompatible instructions in the input files. | |
285 | It also modifies the linker's search strategy for archive libraries, to | |
286 | support the use of libraries specific to each particular | |
287 | architecture, by including in the search loop names suffixed with the | |
288 | string identifying the architecture. | |
289 | ||
290 | For example, if your \c | |
291 | .B ld\c | |
292 | \& command line included `\|\c | |
293 | .B \-ACA\c | |
294 | \|' as | |
295 | well as `\|\c | |
296 | .B \-ltry\c | |
297 | \|', the linker would look (in its built-in search | |
298 | paths, and in any paths you specify with \c | |
299 | .B \-L\c | |
300 | \&) for a library with | |
301 | the names | |
302 | .sp | |
303 | .br | |
304 | try | |
305 | .br | |
306 | libtry.a | |
307 | .br | |
308 | tryca | |
309 | .br | |
310 | libtryca.a | |
311 | .br | |
312 | .sp | |
313 | ||
314 | The first two possibilities would be considered in any event; the last | |
315 | two are due to the use of `\|\c | |
316 | .B \-ACA\c | |
317 | \|'. | |
318 | ||
319 | Future releases of \c | |
320 | .B ld\c | |
321 | \& may support similar functionality for | |
322 | other architecture families. | |
323 | ||
324 | You can meaningfully use \c | |
325 | .B \-A\c | |
326 | \& more than once on a command line, if | |
327 | an architecture family allows combination of target architectures; each | |
328 | use will add another pair of name variants to search for when \c | |
80165535 | 329 | .B \-l |
0e166a63 RP |
330 | specifies a library. |
331 | ||
332 | .TP | |
80165535 | 333 | .BI "\-b " "input-format" |
0e166a63 RP |
334 | Specify the binary format for input object files that follow this option |
335 | on the command line. You don't usually need to specify this, as | |
336 | \c | |
337 | .B ld\c | |
338 | \& is configured to expect as a default input format the most | |
339 | usual format on each machine. \c | |
340 | .I input-format\c | |
341 | \& is a text string, the | |
342 | name of a particular format supported by the BFD libraries. | |
343 | \c | |
344 | .B \-format \c | |
345 | .I input-format\c | |
346 | \&\c | |
346535cc DM |
347 | \& has the same effect, as does the script command |
348 | .BR TARGET . | |
0e166a63 RP |
349 | |
350 | You may want to use this option if you are linking files with an unusual | |
351 | binary format. You can also use \c | |
352 | .B \-b\c | |
353 | \& to switch formats explicitly (when | |
354 | linking object files of different formats), by including | |
355 | \c | |
356 | .B \-b \c | |
357 | .I input-format\c | |
358 | \&\c | |
359 | \& before each group of object files in a | |
360 | particular format. | |
361 | ||
362 | The default format is taken from the environment variable | |
363 | .B GNUTARGET\c | |
364 | \&. You can also define the input | |
365 | format from a script, using the command \c | |
366 | .B TARGET\c | |
367 | \&. | |
368 | ||
369 | .TP | |
370 | .B \-Bstatic | |
4551e108 ILT |
371 | Do not link against shared libraries. This is only meaningful on |
372 | platforms for which shared libraries are supported. | |
373 | ||
374 | .TP | |
375 | .B \-Bdynamic | |
376 | Link against dynamic libraries. This is only meaningful on platforms | |
377 | for which shared libraries are supported. This option is normally the | |
378 | default on such platforms. | |
379 | ||
380 | .TP | |
381 | .B \-Bsymbolic | |
382 | When creating a shared library, bind references to global symbols to | |
383 | the definition within the shared library, if any. Normally, it is | |
384 | possible for a program linked against a shared library to override the | |
385 | definition within the shared library. This option is only meaningful | |
386 | on ELF platforms which support shared libraries. | |
0e166a63 RP |
387 | |
388 | .TP | |
80165535 | 389 | .BI "\-c " "commandfile" |
0e166a63 RP |
390 | Directs \c |
391 | .B ld\c | |
392 | \& to read link commands from the file | |
393 | \c | |
394 | .I commandfile\c | |
395 | \&. These commands will completely override \c | |
396 | .B ld\c | |
397 | \&'s | |
398 | default link format (rather than adding to it); \c | |
399 | .I commandfile\c | |
400 | \& must | |
401 | specify everything necessary to describe the target format. | |
402 | ||
403 | ||
404 | You may also include a script of link commands directly in the command | |
405 | line by bracketing it between `\|\c | |
406 | .B {\c | |
407 | \|' and `\|\c | |
408 | .B }\c | |
409 | \|' characters. | |
410 | ||
411 | .TP | |
412 | .B \-d | |
413 | .TP | |
414 | .B \-dc | |
415 | .TP | |
416 | .B \-dp | |
417 | These three options are equivalent; multiple forms are supported for | |
418 | compatibility with other linkers. Use any of them to make \c | |
80165535 | 419 | .B ld |
0e166a63 RP |
420 | assign space to common symbols even if a relocatable output file is |
421 | specified (\c | |
422 | .B \-r\c | |
423 | \&). The script command | |
424 | \c | |
425 | .B FORCE_COMMON_ALLOCATION\c | |
426 | \& has the same effect. | |
427 | ||
428 | .TP | |
80165535 | 429 | .BI "-defsym " "symbol" "\fR = \fP" expression |
0e166a63 RP |
430 | Create a global symbol in the output file, containing the absolute |
431 | address given by \c | |
432 | .I expression\c | |
433 | \&. You may use this option as many | |
434 | times as necessary to define multiple symbols in the command line. A | |
435 | limited form of arithmetic is supported for the \c | |
436 | .I expression\c | |
437 | \& in this | |
438 | context: you may give a hexadecimal constant or the name of an existing | |
439 | symbol, or use \c | |
440 | .B +\c | |
441 | \& and \c | |
442 | .B \-\c | |
443 | \& to add or subtract hexadecimal | |
444 | constants or symbols. If you need more elaborate expressions, consider | |
445 | using the linker command language from a script. | |
446 | ||
447 | .TP | |
448 | .BI "-e " "entry"\c | |
449 | \& | |
450 | Use \c | |
451 | .I entry\c | |
452 | \& as the explicit symbol for beginning execution of your | |
453 | program, rather than the default entry point. for a | |
454 | discussion of defaults and other ways of specifying the | |
455 | entry point. | |
456 | ||
39a6e282 ILT |
457 | .TP |
458 | .B \-embedded\-relocs | |
459 | This option is only meaningful when linking MIPS embedded PIC code, | |
460 | generated by the | |
461 | .B \-membedded\-pic | |
462 | option to the GNU compiler and assembler. It causes the linker to | |
463 | create a table which may be used at runtime to relocate any data which | |
464 | was statically initialized to pointer values. See the code in | |
465 | testsuite/ld-empic for details. | |
466 | ||
7ec9d825 ILT |
467 | .TP |
468 | .B \-E | |
4bdd9722 ILT |
469 | .TP |
470 | .B \-export\-dynamic | |
471 | When creating an ELF file, add all symbols to the dynamic symbol table. | |
472 | Normally, the dynamic symbol table contains only symbols which are used | |
473 | by a dynamic object. This option is needed for some uses of | |
474 | .I dlopen. | |
475 | ||
0e166a63 RP |
476 | .TP |
477 | .B \-F | |
478 | .TP | |
80165535 | 479 | .BI "-F" "format" |
0e166a63 RP |
480 | Some older linkers used this option throughout a compilation toolchain |
481 | for specifying object-file format for both input and output object | |
482 | files. \c | |
483 | .B ld\c | |
484 | \&'s mechanisms (the \c | |
485 | .B \-b\c | |
486 | \& or \c | |
487 | .B \-format\c | |
488 | \& options | |
489 | for input files, the \c | |
490 | .B TARGET\c | |
491 | \& command in linker scripts for output | |
492 | files, the \c | |
493 | .B GNUTARGET\c | |
494 | \& environment variable) are more flexible, but | |
495 | but it accepts (and ignores) the \c | |
496 | .B \-F\c | |
497 | \& option flag for compatibility | |
498 | with scripts written to call the old linker. | |
499 | ||
500 | .TP | |
80165535 | 501 | .BI "\-format " "input\-format" |
0e166a63 RP |
502 | Synonym for \c |
503 | .B \-b\c | |
504 | \& \c | |
2a28d8b0 | 505 | .I input\-format\c |
0e166a63 RP |
506 | \&. |
507 | ||
508 | .TP | |
509 | .B \-g | |
510 | Accepted, but ignored; provided for compatibility with other tools. | |
511 | ||
8ddef552 DM |
512 | .TP |
513 | .BI "\-G " "size"\c | |
514 | Set the maximum size of objects to be optimized using the GP register | |
515 | to | |
516 | .I size | |
517 | under MIPS ECOFF. Ignored for other object file formats. | |
518 | ||
bf065bfd DM |
519 | .TP |
520 | .B \-\-help | |
521 | Print a summary of the command-line options on the standard output and exit. | |
522 | This option and | |
523 | .B \-\-version | |
524 | begin with two dashes instead of one | |
525 | for compatibility with other GNU programs. The other options start with | |
526 | only one dash for compatibility with other linkers. | |
527 | ||
0e166a63 RP |
528 | .TP |
529 | .B \-i | |
530 | Perform an incremental link (same as option \c | |
531 | .B \-r\c | |
532 | \&). | |
533 | ||
534 | .TP | |
2a28d8b0 | 535 | .BI "\-l" "ar"\c |
0e166a63 RP |
536 | \& |
537 | Add an archive file \c | |
538 | .I ar\c | |
539 | \& to the list of files to link. This | |
540 | option may be used any number of times. \c | |
541 | .B ld\c | |
542 | \& will search its | |
543 | path-list for occurrences of \c | |
544 | .B lib\c | |
545 | .I ar\c | |
546 | \&.a\c | |
547 | \& for every \c | |
80165535 | 548 | .I ar |
0e166a63 RP |
549 | specified. |
550 | ||
551 | .TP | |
80165535 | 552 | .BI "\-L" "searchdir" |
0e166a63 RP |
553 | This command adds path \c |
554 | .I searchdir\c | |
555 | \& to the list of paths that | |
556 | \c | |
557 | .B ld\c | |
558 | \& will search for archive libraries. You may use this option | |
559 | any number of times. | |
560 | ||
561 | The default set of paths searched (without being specified with | |
562 | \c | |
563 | .B \-L\c | |
564 | \&) depends on what emulation mode \c | |
565 | .B ld\c | |
566 | \& is using, and in | |
567 | some cases also on how it was configured. The | |
568 | paths can also be specified in a link script with the \c | |
80165535 | 569 | .B SEARCH_DIR |
0e166a63 RP |
570 | command. |
571 | ||
572 | .TP | |
573 | .B \-M | |
0e166a63 RP |
574 | Print (to the standard output file) a link map\(em\&diagnostic information |
575 | about where symbols are mapped by \c | |
576 | .B ld\c | |
577 | \&, and information on global | |
578 | common storage allocation. | |
579 | ||
d18a4527 DM |
580 | .TP |
581 | .BI "\-Map " "mapfile"\c | |
582 | Print to the file | |
583 | .I mapfile | |
584 | a link map\(em\&diagnostic information | |
585 | about where symbols are mapped by \c | |
586 | .B ld\c | |
587 | \&, and information on global | |
588 | common storage allocation. | |
589 | ||
8ddef552 DM |
590 | .TP |
591 | .BI "\-m " "emulation"\c | |
592 | Emulate the | |
593 | .I emulation | |
594 | linker. You can list the available emulations with the | |
a82ae15d | 595 | .I \-\-verbose |
1f59c7a7 ILT |
596 | or |
597 | .I \-V | |
598 | options. This option overrides the compiled-in default, which is the | |
8ddef552 DM |
599 | system for which you configured |
600 | .BR ld . | |
601 | ||
0e166a63 RP |
602 | .TP |
603 | .B \-N | |
604 | specifies readable and writable \c | |
605 | .B text\c | |
606 | \& and \c | |
607 | .B data\c | |
608 | \& sections. If | |
609 | the output format supports Unix style magic numbers, the output is | |
610 | marked as \c | |
611 | .B OMAGIC\c | |
612 | \&. | |
613 | ||
614 | When you use the `\|\c | |
615 | .B \-N\c | |
616 | \&\|' option, the linker does not page-align the | |
617 | data segment. | |
618 | ||
619 | .TP | |
620 | .B \-n | |
621 | sets the text segment to be read only, and \c | |
622 | .B NMAGIC\c | |
623 | \& is written | |
624 | if possible. | |
625 | ||
626 | .TP | |
2a28d8b0 | 627 | .B \-noinhibit\-exec |
0e166a63 RP |
628 | Normally, the linker will not produce an output file if it encounters |
629 | errors during the link process. With this flag, you can specify that | |
630 | you wish the output file retained even after non-fatal errors. | |
631 | ||
e920526d ILT |
632 | .TP |
633 | .B \-no\-keep\-memory | |
634 | The linker normally optimizes for speed over memory usage by caching | |
635 | the symbol tables of input files in memory. This option tells the | |
636 | linker to instead optimize for memory usage, by rereading the symbol | |
637 | tables as necessary. This may be required if the linker runs out of | |
638 | memory space while linking a large executable. | |
639 | ||
0e166a63 | 640 | .TP |
80165535 | 641 | .BI "\-o " "output" |
0e166a63 RP |
642 | .I output\c |
643 | \& is a name for the program produced by \c | |
644 | .B ld\c | |
645 | \&; if this | |
646 | option is not specified, the name `\|\c | |
647 | .B a.out\c | |
648 | \|' is used by default. The | |
649 | script command \c | |
650 | .B OUTPUT\c | |
651 | \& can also specify the output file name. | |
652 | ||
346535cc | 653 | .TP |
80165535 | 654 | .BI "\-oformat " "output\-format" |
346535cc DM |
655 | Specify the binary format for the output object file. |
656 | You don't usually need to specify this, as | |
657 | \c | |
658 | .B ld\c | |
659 | \& is configured to produce as a default output format the most | |
660 | usual format on each machine. \c | |
661 | .I output-format\c | |
662 | \& is a text string, the | |
663 | name of a particular format supported by the BFD libraries. | |
664 | The script command | |
665 | .B OUTPUT_FORMAT | |
666 | can also specify the output format, but this option overrides it. | |
667 | ||
0e166a63 | 668 | .TP |
80165535 | 669 | .BI "\-R " "filename" |
0e166a63 RP |
670 | Read symbol names and their addresses from \c |
671 | .I filename\c | |
672 | \&, but do not | |
673 | relocate it or include it in the output. This allows your output file | |
674 | to refer symbolically to absolute locations of memory defined in other | |
675 | programs. | |
676 | ||
677 | .TP | |
678 | .B \-relax | |
679 | An option with machine dependent effects. Currently this option is only | |
680 | supported on the H8/300. | |
681 | ||
682 | On some platforms, use this option to perform global optimizations that | |
683 | become possible when the linker resolves addressing in your program, such | |
684 | as relaxing address modes and synthesizing new instructions in the | |
685 | output object file. | |
686 | ||
687 | On platforms where this is not supported, `\|\c | |
688 | .B \-relax\c | |
689 | \&\|' is accepted, but has no effect. | |
690 | ||
691 | .TP | |
692 | .B \-r | |
693 | Generates relocatable output\(em\&i.e., generate an output file that can in | |
694 | turn serve as input to \c | |
695 | .B ld\c | |
696 | \&. This is often called \c | |
697 | .I partial | |
698 | linking\c | |
699 | \&. As a side effect, in environments that support standard Unix | |
700 | magic numbers, this option also sets the output file's magic number to | |
701 | \c | |
702 | .B OMAGIC\c | |
703 | \&. | |
704 | If this option is not specified, an absolute file is produced. When | |
705 | linking C++ programs, this option \c | |
706 | .I will not\c | |
707 | \& resolve references to | |
708 | constructors; \c | |
709 | .B \-Ur\c | |
710 | \& is an alternative. | |
711 | ||
712 | This option does the same as \c | |
713 | .B \-i\c | |
714 | \&. | |
715 | ||
5caef232 ILT |
716 | .TP |
717 | .B \-rpath\ \fIdirectory | |
718 | Add a directory to the runtime library search path. This is used when | |
719 | linking an ELF executable with shared objects. All | |
720 | .B \-rpath | |
721 | arguments are concatenated and passed to the runtime linker, which uses | |
722 | them to locate shared objects at runtime. The | |
723 | .B \-rpath | |
724 | option is also used when locating shared objects which are needed by | |
725 | shared objects explicitly included in the link; see the description of | |
726 | the | |
727 | .B \-rpath\-link | |
20406675 ILT |
728 | option. If |
729 | .B \-rpath | |
730 | is not used when linking an ELF executable, the contents of the | |
731 | environment variable | |
732 | .B LD_RUN_PATH | |
733 | will be used if it is defined. | |
5caef232 ILT |
734 | |
735 | The | |
736 | .B \-rpath | |
737 | option may also be used on SunOS. By default, on SunOS, the linker | |
738 | will form a runtime search patch out of all the | |
739 | .B \-L | |
740 | options it is given. If a | |
4bdd9722 ILT |
741 | .B \-rpath |
742 | option is used, the runtime search path will be formed exclusively | |
743 | using the | |
5caef232 ILT |
744 | .B \-rpath |
745 | options, ignoring | |
746 | the | |
747 | .B \-L | |
748 | options. This can be useful when using gcc, which adds many | |
749 | .B \-L | |
750 | options which may be on NFS mounted filesystems. | |
751 | ||
752 | .TP | |
753 | .B \-rpath\-link\ \fIdirectory | |
235c6a67 ILT |
754 | When using ELF or SunOS, one shared library may require another. This |
755 | happens when an | |
5caef232 ILT |
756 | .B ld\ \-shared |
757 | link includes a shared library as one of the input files. | |
758 | ||
759 | When the linker encounters such a dependency when doing a non-shared, | |
760 | non-relocateable link, it will automatically try to locate the required | |
761 | shared library and include it in the link, if it is not included | |
762 | explicitly. In such a case, the | |
763 | .B \-rpath\-link | |
764 | option specifies the first set of directories to search. The | |
765 | .B \-rpath\-link | |
766 | option may specify a sequence of directory names either by specifying | |
767 | a list of names separated by colons, or by appearing multiple times. | |
768 | ||
769 | If the required shared library is not found, the linker will issue a | |
770 | warning and continue with the link. | |
771 | ||
0e166a63 RP |
772 | .TP |
773 | .B \-S | |
774 | Omits debugger symbol information (but not all symbols) from the output file. | |
775 | ||
776 | .TP | |
777 | .B \-s | |
778 | Omits all symbol information from the output file. | |
779 | ||
4551e108 ILT |
780 | .TP |
781 | .B \-shared | |
235c6a67 ILT |
782 | Create a shared library. This is currently only supported on ELF and |
783 | SunOS platforms (on SunOS it is not required, as the linker will | |
784 | automatically create a shared library when there are undefined symbols | |
785 | and the | |
786 | .B \-e | |
787 | option is not used). | |
4551e108 | 788 | |
0e166a63 | 789 | .TP |
2a28d8b0 DM |
790 | .B \-sort\-common |
791 | Normally, when | |
792 | .B ld | |
793 | places the global common symbols in the appropriate output sections, | |
794 | it sorts them by size. First come all the one byte symbols, then all | |
795 | the two bytes, then all the four bytes, and then everything else. | |
da08e9b9 DM |
796 | This is to prevent gaps between symbols due to |
797 | alignment constraints. This option disables that sorting. | |
2a28d8b0 | 798 | |
ec586565 ILT |
799 | .TP |
800 | .B \-split\-by\-reloc\ \fIcount | |
801 | Trys to creates extra sections in the output file so that no single | |
802 | output section in the file contains more than | |
803 | .I count | |
804 | relocations. | |
805 | This is useful when generating huge relocatable for downloading into | |
806 | certain real time kernels with the COFF object file format; since COFF | |
807 | cannot represent more than 65535 relocations in a single section. | |
808 | Note that this will fail to work with object file formats which do not | |
809 | support arbitrary sections. The linker will not split up individual | |
810 | input sections for redistribution, so if a single input section | |
811 | contains more than | |
812 | .I count | |
813 | relocations one output section will contain that many relocations. | |
814 | ||
815 | .TP | |
816 | .B \-split\-by\-file | |
817 | Similar to | |
818 | .B \-split\-by\-reloc | |
819 | but creates a new output section for each input file. | |
820 | ||
2a28d8b0 DM |
821 | .TP |
822 | .BI "\-Tbss " "org"\c | |
0e166a63 | 823 | .TP |
2a28d8b0 | 824 | .BI "\-Tdata " "org"\c |
0e166a63 | 825 | .TP |
2a28d8b0 | 826 | .BI "\-Ttext " "org"\c |
0e166a63 RP |
827 | Use \c |
828 | .I org\c | |
829 | \& as the starting address for\(em\&respectively\(em\&the | |
830 | \c | |
831 | .B bss\c | |
832 | \&, \c | |
833 | .B data\c | |
834 | \&, or the \c | |
835 | .B text\c | |
836 | \& segment of the output file. | |
837 | \c | |
838 | .I textorg\c | |
839 | \& must be a hexadecimal integer. | |
840 | ||
841 | .TP | |
80165535 | 842 | .BI "\-T " "commandfile" |
0e166a63 RP |
843 | Equivalent to \c |
844 | .B \-c \c | |
845 | .I commandfile\c | |
846 | \&\c | |
847 | \&; supported for compatibility with | |
848 | other tools. | |
849 | ||
850 | .TP | |
851 | .B \-t | |
852 | Prints names of input files as \c | |
853 | .B ld\c | |
854 | \& processes them. | |
855 | ||
856 | .TP | |
2a28d8b0 | 857 | .BI "\-u " "sym" |
0e166a63 RP |
858 | Forces \c |
859 | .I sym\c | |
860 | \& to be entered in the output file as an undefined symbol. | |
861 | This may, for example, trigger linking of additional modules from | |
862 | standard libraries. \c | |
863 | .B \-u\c | |
864 | \& may be repeated with different option | |
865 | arguments to enter additional undefined symbols. | |
866 | ||
867 | .TP | |
868 | .B \-Ur | |
869 | For anything other than C++ programs, this option is equivalent to | |
870 | \c | |
871 | .B \-r\c | |
872 | \&: it generates relocatable output\(em\&i.e., an output file that can in | |
873 | turn serve as input to \c | |
874 | .B ld\c | |
875 | \&. When linking C++ programs, \c | |
80165535 | 876 | .B \-Ur |
0e166a63 RP |
877 | .I will\c |
878 | \& resolve references to constructors, unlike \c | |
879 | .B \-r\c | |
880 | \&. | |
881 | ||
8ddef552 | 882 | .TP |
a82ae15d | 883 | .B \-\-verbose |
8ddef552 DM |
884 | Display the version number for \c |
885 | .B ld | |
886 | and list the supported emulations. | |
de87cdb4 | 887 | Display which input files can and can not be opened. |
8ddef552 | 888 | |
0e166a63 | 889 | .TP |
a82ae15d | 890 | .B \-v, \-V |
0e166a63 RP |
891 | Display the version number for \c |
892 | .B ld\c | |
893 | \&. | |
1f59c7a7 ILT |
894 | The |
895 | .B \-V | |
896 | option also lists the supported emulations. | |
0e166a63 | 897 | |
bf065bfd DM |
898 | .TP |
899 | .B \-\-version | |
900 | Display the version number for \c | |
901 | .B ld | |
902 | and exit. | |
903 | ||
2a28d8b0 DM |
904 | .TP |
905 | .B \-warn\-common | |
906 | Warn when a common symbol is combined with another common symbol or with | |
907 | a symbol definition. Unix linkers allow this somewhat sloppy practice, | |
908 | but linkers on some other operating systems do not. This option allows | |
909 | you to find potential problems from combining global symbols. | |
910 | ||
a89d9f5b ILT |
911 | .TP |
912 | .B \-warn\-constructors | |
913 | Warn if any global constructors are used. This is only useful for a | |
914 | few object file formats. For formats like COFF or ELF, the linker can | |
915 | not detect the use of global constructors. | |
916 | ||
4b7d2399 ILT |
917 | .TP |
918 | .B \-warn\-multiple\-gp | |
919 | Warn if the output file requires multiple global-pointer values. This | |
920 | option is only meaningful for certain processors, such as the Alpha. | |
921 | ||
809ee7e0 ILT |
922 | .TP |
923 | .B \-warn\-once | |
924 | Only warn once for each undefined symbol, rather than once per module | |
925 | which refers to it. | |
926 | ||
ee499d81 ILT |
927 | .TP |
928 | .B \-\-whole\-archive | |
3c8deccc ILT |
929 | For each archive mentioned on the command line after the |
930 | .B \-\-whole\-archive | |
931 | option, include every object file in the archive in the link, rather | |
932 | than searching the archive for the required object files. This is | |
933 | normally used to turn an archive file into a shared library, forcing | |
934 | every object to be included in the resulting shared library. | |
935 | ||
936 | .TP | |
937 | .B \-\-no\-whole\-archive | |
938 | Turn off the effect of the | |
939 | .B \-\-whole\-archive | |
940 | option for archives which appear later on the command line. | |
ee499d81 | 941 | |
e3d73386 ILT |
942 | .TP |
943 | .BI "--wrap " "symbol" | |
944 | Use a wrapper function for | |
945 | .I symbol. | |
946 | Any undefined reference to | |
947 | .I symbol | |
948 | will be resolved to | |
949 | .BI "__wrap_" "symbol". | |
950 | Any undefined reference to | |
951 | .BI "__real_" "symbol" | |
952 | will be resolved to | |
953 | .I symbol. | |
954 | ||
0e166a63 RP |
955 | .TP |
956 | .B \-X | |
21a2f026 ILT |
957 | Delete all temporary local symbols. For most targets, this is all local |
958 | symbols whose names begin with `\|\c | |
0e166a63 RP |
959 | .B L\c |
960 | \|'. | |
961 | ||
962 | .TP | |
963 | .B \-x | |
21a2f026 | 964 | Delete all local symbols. |
0e166a63 RP |
965 | |
966 | .PP | |
967 | ||
968 | .SH ENVIRONMENT | |
969 | \c | |
8ddef552 | 970 | You can change the behavior of |
0e166a63 | 971 | .B ld\c |
8ddef552 | 972 | \& with the environment variable \c |
0e166a63 | 973 | .B GNUTARGET\c |
8ddef552 | 974 | \&. |
0e166a63 RP |
975 | |
976 | \c | |
977 | .B GNUTARGET\c | |
978 | \& determines the input-file object format if you don't | |
979 | use \c | |
980 | .B \-b\c | |
981 | \& (or its synonym \c | |
982 | .B \-format\c | |
983 | \&). Its value should be one | |
984 | of the BFD names for an input format. If there is no | |
985 | \c | |
986 | .B GNUTARGET\c | |
987 | \& in the environment, \c | |
988 | .B ld\c | |
989 | \& uses the natural format | |
990 | of the host. If \c | |
991 | .B GNUTARGET\c | |
992 | \& is set to \c | |
993 | .B default\c | |
994 | \& then BFD attempts to discover the | |
995 | input format by examining binary input files; this method often | |
996 | succeeds, but there are potential ambiguities, since there is no method | |
997 | of ensuring that the magic number used to flag object-file formats is | |
998 | unique. However, the configuration procedure for BFD on each system | |
999 | places the conventional format for that system first in the search-list, | |
1000 | so ambiguities are resolved in favor of convention. | |
1001 | ||
0e166a63 RP |
1002 | .PP |
1003 | ||
1004 | .SH "SEE ALSO" | |
1005 | ||
1006 | .BR objdump ( 1 ) | |
1007 | .br | |
1008 | .br | |
1009 | .RB "`\|" ld "\|' and `\|" binutils "\|'" | |
1010 | entries in | |
1011 | .B info\c | |
1012 | .br | |
1013 | .I | |
1014 | ld: the GNU linker\c | |
1015 | , Steve Chamberlain and Roland Pesch; | |
1016 | .I | |
1017 | The GNU Binary Utilities\c | |
1018 | , Roland H. Pesch. | |
1019 | ||
1020 | .SH COPYING | |
1021 | Copyright (c) 1991, 1992 Free Software Foundation, Inc. | |
1022 | .PP | |
1023 | Permission is granted to make and distribute verbatim copies of | |
1024 | this manual provided the copyright notice and this permission notice | |
1025 | are preserved on all copies. | |
1026 | .PP | |
1027 | Permission is granted to copy and distribute modified versions of this | |
1028 | manual under the conditions for verbatim copying, provided that the | |
1029 | entire resulting derived work is distributed under the terms of a | |
1030 | permission notice identical to this one. | |
1031 | .PP | |
1032 | Permission is granted to copy and distribute translations of this | |
1033 | manual into another language, under the above conditions for modified | |
1034 | versions, except that this permission notice may be included in | |
1035 | translations approved by the Free Software Foundation instead of in | |
1036 | the original English. |