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  15. <title>objcopy (GNU Binary Utilities)</title>

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  57. </head>

  58. 

  59. <body lang="en">

  60. <a name="objcopy"></a>

  61. <div class="header">

  62. <p>

  63. Next: <a href="objdump.html#objdump" accesskey="n" rel="next">objdump</a>, Previous: <a href="nm.html#nm" accesskey="p" rel="prev">nm</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Binutils-Index.html#Binutils-Index" title="Index" rel="index">Index</a>]</p>

  64. </div>

  65. <hr>

  66. <a name="objcopy-1"></a>

  67. <h2 class="chapter">3 objcopy</h2>

  68. 

  69. 

  70. <div class="smallexample">

  71. <pre class="smallexample">objcopy [<samp>-F</samp> <var>bfdname</var>|<samp>--target=</samp><var>bfdname</var>]

  72.         [<samp>-I</samp> <var>bfdname</var>|<samp>--input-target=</samp><var>bfdname</var>]

  73.         [<samp>-O</samp> <var>bfdname</var>|<samp>--output-target=</samp><var>bfdname</var>]

  74.         [<samp>-B</samp> <var>bfdarch</var>|<samp>--binary-architecture=</samp><var>bfdarch</var>]

  75.         [<samp>-S</samp>|<samp>--strip-all</samp>]

  76.         [<samp>-g</samp>|<samp>--strip-debug</samp>]

  77.         [<samp>--strip-unneeded</samp>]

  78.         [<samp>-K</samp> <var>symbolname</var>|<samp>--keep-symbol=</samp><var>symbolname</var>]

  79.         [<samp>-N</samp> <var>symbolname</var>|<samp>--strip-symbol=</samp><var>symbolname</var>]

  80.         [<samp>--strip-unneeded-symbol=</samp><var>symbolname</var>]

  81.         [<samp>-G</samp> <var>symbolname</var>|<samp>--keep-global-symbol=</samp><var>symbolname</var>]

  82.         [<samp>--localize-hidden</samp>]

  83.         [<samp>-L</samp> <var>symbolname</var>|<samp>--localize-symbol=</samp><var>symbolname</var>]

  84.         [<samp>--globalize-symbol=</samp><var>symbolname</var>]

  85.         [<samp>--globalize-symbols=</samp><var>filename</var>]

  86.         [<samp>-W</samp> <var>symbolname</var>|<samp>--weaken-symbol=</samp><var>symbolname</var>]

  87.         [<samp>-w</samp>|<samp>--wildcard</samp>]

  88.         [<samp>-x</samp>|<samp>--discard-all</samp>]

  89.         [<samp>-X</samp>|<samp>--discard-locals</samp>]

  90.         [<samp>-b</samp> <var>byte</var>|<samp>--byte=</samp><var>byte</var>]

  91.         [<samp>-i</samp> [<var>breadth</var>]|<samp>--interleave</samp>[=<var>breadth</var>]]

  92.         [<samp>--interleave-width=</samp><var>width</var>]

  93.         [<samp>-j</samp> <var>sectionpattern</var>|<samp>--only-section=</samp><var>sectionpattern</var>]

  94.         [<samp>-R</samp> <var>sectionpattern</var>|<samp>--remove-section=</samp><var>sectionpattern</var>]

  95.         [<samp>--keep-section=</samp><var>sectionpattern</var>]

  96.         [<samp>--remove-relocations=</samp><var>sectionpattern</var>]

  97.         [<samp>-p</samp>|<samp>--preserve-dates</samp>]

  98.         [<samp>-D</samp>|<samp>--enable-deterministic-archives</samp>]

  99.         [<samp>-U</samp>|<samp>--disable-deterministic-archives</samp>]

  100.         [<samp>--debugging</samp>]

  101.         [<samp>--gap-fill=</samp><var>val</var>]

  102.         [<samp>--pad-to=</samp><var>address</var>]

  103.         [<samp>--set-start=</samp><var>val</var>]

  104.         [<samp>--adjust-start=</samp><var>incr</var>]

  105.         [<samp>--change-addresses=</samp><var>incr</var>]

  106.         [<samp>--change-section-address</samp> <var>sectionpattern</var>{=,+,-}<var>val</var>]

  107.         [<samp>--change-section-lma</samp> <var>sectionpattern</var>{=,+,-}<var>val</var>]

  108.         [<samp>--change-section-vma</samp> <var>sectionpattern</var>{=,+,-}<var>val</var>]

  109.         [<samp>--change-warnings</samp>] [<samp>--no-change-warnings</samp>]

  110.         [<samp>--set-section-flags</samp> <var>sectionpattern</var>=<var>flags</var>]

  111.         [<samp>--set-section-alignment</samp> <var>sectionpattern</var>=<var>align</var>]

  112.         [<samp>--add-section</samp> <var>sectionname</var>=<var>filename</var>]

  113.         [<samp>--dump-section</samp> <var>sectionname</var>=<var>filename</var>]

  114.         [<samp>--update-section</samp> <var>sectionname</var>=<var>filename</var>]

  115.         [<samp>--rename-section</samp> <var>oldname</var>=<var>newname</var>[,<var>flags</var>]]

  116.         [<samp>--long-section-names</samp> {enable,disable,keep}]

  117.         [<samp>--change-leading-char</samp>] [<samp>--remove-leading-char</samp>]

  118.         [<samp>--reverse-bytes=</samp><var>num</var>]

  119.         [<samp>--srec-len=</samp><var>ival</var>] [<samp>--srec-forceS3</samp>]

  120.         [<samp>--redefine-sym</samp> <var>old</var>=<var>new</var>]

  121.         [<samp>--redefine-syms=</samp><var>filename</var>]

  122.         [<samp>--weaken</samp>]

  123.         [<samp>--keep-symbols=</samp><var>filename</var>]

  124.         [<samp>--strip-symbols=</samp><var>filename</var>]

  125.         [<samp>--strip-unneeded-symbols=</samp><var>filename</var>]

  126.         [<samp>--keep-global-symbols=</samp><var>filename</var>]

  127.         [<samp>--localize-symbols=</samp><var>filename</var>]

  128.         [<samp>--weaken-symbols=</samp><var>filename</var>]

  129.         [<samp>--add-symbol</samp> <var>name</var>=[<var>section</var>:]<var>value</var>[,<var>flags</var>]]

  130.         [<samp>--alt-machine-code=</samp><var>index</var>]

  131.         [<samp>--prefix-symbols=</samp><var>string</var>]

  132.         [<samp>--prefix-sections=</samp><var>string</var>]

  133.         [<samp>--prefix-alloc-sections=</samp><var>string</var>]

  134.         [<samp>--add-gnu-debuglink=</samp><var>path-to-file</var>]

  135.         [<samp>--keep-file-symbols</samp>]

  136.         [<samp>--only-keep-debug</samp>]

  137.         [<samp>--strip-dwo</samp>]

  138.         [<samp>--extract-dwo</samp>]

  139.         [<samp>--extract-symbol</samp>]

  140.         [<samp>--writable-text</samp>]

  141.         [<samp>--readonly-text</samp>]

  142.         [<samp>--pure</samp>]

  143.         [<samp>--impure</samp>]

  144.         [<samp>--file-alignment=</samp><var>num</var>]

  145.         [<samp>--heap=</samp><var>size</var>]

  146.         [<samp>--image-base=</samp><var>address</var>]

  147.         [<samp>--section-alignment=</samp><var>num</var>]

  148.         [<samp>--stack=</samp><var>size</var>]

  149.         [<samp>--subsystem=</samp><var>which</var>:<var>major</var>.<var>minor</var>]

  150.         [<samp>--compress-debug-sections</samp>]

  151.         [<samp>--decompress-debug-sections</samp>]

  152.         [<samp>--elf-stt-common=<var>val</var></samp>]

  153.         [<samp>--merge-notes</samp>]

  154.         [<samp>--no-merge-notes</samp>]

  155.         [<samp>--verilog-data-width=<var>val</var></samp>]

  156.         [<samp>-v</samp>|<samp>--verbose</samp>]

  157.         [<samp>-V</samp>|<samp>--version</samp>]

  158.         [<samp>--help</samp>] [<samp>--info</samp>]

  159.         <var>infile</var> [<var>outfile</var>]

  160. </pre></div>

  161. 

  162. <p>The <small>GNU</small> <code>objcopy</code> utility copies the contents of an object

  163. file to another.  <code>objcopy</code> uses the <small>GNU</small> <small>BFD</small> Library to

  164. read and write the object files.  It can write the destination object

  165. file in a format different from that of the source object file.  The

  166. exact behavior of <code>objcopy</code> is controlled by command-line options.

  167. Note that <code>objcopy</code> should be able to copy a fully linked file

  168. between any two formats. However, copying a relocatable object file

  169. between any two formats may not work as expected.

  170. </p>

  171. <p><code>objcopy</code> creates temporary files to do its translations and

  172. deletes them afterward.  <code>objcopy</code> uses <small>BFD</small> to do all its

  173. translation work; it has access to all the formats described in <small>BFD</small>

  174. and thus is able to recognize most formats without being told

  175. explicitly.  See <a href="http://sourceware.org/binutils/docs/ld/BFD.html#BFD">BFD</a> in <cite>Using LD</cite>.

  176. </p>

  177. <p><code>objcopy</code> can be used to generate S-records by using an output

  178. target of &lsquo;<samp>srec</samp>&rsquo; (e.g., use &lsquo;<samp>-O srec</samp>&rsquo;).

  179. </p>

  180. <p><code>objcopy</code> can be used to generate a raw binary file by using an

  181. output target of &lsquo;<samp>binary</samp>&rsquo; (e.g., use <samp>-O binary</samp>).  When

  182. <code>objcopy</code> generates a raw binary file, it will essentially produce

  183. a memory dump of the contents of the input object file.  All symbols and

  184. relocation information will be discarded.  The memory dump will start at

  185. the load address of the lowest section copied into the output file.

  186. </p>

  187. <p>When generating an S-record or a raw binary file, it may be helpful to

  188. use <samp>-S</samp> to remove sections containing debugging information.  In

  189. some cases <samp>-R</samp> will be useful to remove sections which contain

  190. information that is not needed by the binary file.

  191. </p>

  192. <p>Note&mdash;<code>objcopy</code> is not able to change the endianness of its input

  193. files.  If the input format has an endianness (some formats do not),

  194. <code>objcopy</code> can only copy the inputs into file formats that have the

  195. same endianness or which have no endianness (e.g., &lsquo;<samp>srec</samp>&rsquo;).

  196. (However, see the <samp>--reverse-bytes</samp> option.)

  197. </p>

  198. 

  199. 

  200. <dl compact="compact">

  201. <dt><code><var>infile</var></code></dt>

  202. <dt><code><var>outfile</var></code></dt>

  203. <dd><p>The input and output files, respectively.

  204. If you do not specify <var>outfile</var>, <code>objcopy</code> creates a

  205. temporary file and destructively renames the result with

  206. the name of <var>infile</var>.

  207. </p>

  208. </dd>

  209. <dt><code>-I <var>bfdname</var></code></dt>

  210. <dt><code>--input-target=<var>bfdname</var></code></dt>

  211. <dd><p>Consider the source file&rsquo;s object format to be <var>bfdname</var>, rather than

  212. attempting to deduce it.  See <a href="Target-Selection.html#Target-Selection">Target Selection</a>, for more information.

  213. </p>

  214. </dd>

  215. <dt><code>-O <var>bfdname</var></code></dt>

  216. <dt><code>--output-target=<var>bfdname</var></code></dt>

  217. <dd><p>Write the output file using the object format <var>bfdname</var>.

  218. See <a href="Target-Selection.html#Target-Selection">Target Selection</a>, for more information.

  219. </p>

  220. </dd>

  221. <dt><code>-F <var>bfdname</var></code></dt>

  222. <dt><code>--target=<var>bfdname</var></code></dt>

  223. <dd><p>Use <var>bfdname</var> as the object format for both the input and the output

  224. file; i.e., simply transfer data from source to destination with no

  225. translation.  See <a href="Target-Selection.html#Target-Selection">Target Selection</a>, for more information.

  226. </p>

  227. </dd>

  228. <dt><code>-B <var>bfdarch</var></code></dt>

  229. <dt><code>--binary-architecture=<var>bfdarch</var></code></dt>

  230. <dd><p>Useful when transforming a architecture-less input file into an object file.

  231. In this case the output architecture can be set to <var>bfdarch</var>.  This

  232. option will be ignored if the input file has a known <var>bfdarch</var>.  You

  233. can access this binary data inside a program by referencing the special

  234. symbols that are created by the conversion process.  These symbols are

  235. called _binary_<var>objfile</var>_start, _binary_<var>objfile</var>_end and

  236. _binary_<var>objfile</var>_size.  e.g. you can transform a picture file into

  237. an object file and then access it in your code using these symbols.

  238. </p>

  239. </dd>

  240. <dt><code>-j <var>sectionpattern</var></code></dt>

  241. <dt><code>--only-section=<var>sectionpattern</var></code></dt>

  242. <dd><p>Copy only the indicated sections from the input file to the output file.

  243. This option may be given more than once.  Note that using this option

  244. inappropriately may make the output file unusable.  Wildcard

  245. characters are accepted in <var>sectionpattern</var>.

  246. </p>

  247. <p>If the first character of <var>sectionpattern</var> is the exclamation

  248. point (!) then matching sections will not be copied, even if earlier

  249. use of <samp>--only-section</samp> on the same command line would

  250. otherwise copy it.  For example:

  251. </p>

  252. <div class="smallexample">

  253. <pre class="smallexample">  --only-section=.text.* --only-section=!.text.foo

  254. </pre></div>

  255. 

  256. <p>will copy all sectinos maching &rsquo;.text.*&rsquo; but not the section

  257. &rsquo;.text.foo&rsquo;.

  258. </p>

  259. </dd>

  260. <dt><code>-R <var>sectionpattern</var></code></dt>

  261. <dt><code>--remove-section=<var>sectionpattern</var></code></dt>

  262. <dd><p>Remove any section matching <var>sectionpattern</var> from the output file.

  263. This option may be given more than once.  Note that using this option

  264. inappropriately may make the output file unusable.  Wildcard

  265. characters are accepted in <var>sectionpattern</var>.  Using both the

  266. <samp>-j</samp> and <samp>-R</samp> options together results in undefined

  267. behaviour.

  268. </p>

  269. <p>If the first character of <var>sectionpattern</var> is the exclamation

  270. point (!) then matching sections will not be removed even if an

  271. earlier use of <samp>--remove-section</samp> on the same command line

  272. would otherwise remove it.  For example:

  273. </p>

  274. <div class="smallexample">

  275. <pre class="smallexample">  --remove-section=.text.* --remove-section=!.text.foo

  276. </pre></div>

  277. 

  278. <p>will remove all sections matching the pattern &rsquo;.text.*&rsquo;, but will not

  279. remove the section &rsquo;.text.foo&rsquo;.

  280. </p>

  281. </dd>

  282. <dt><code>--keep-section=<var>sectionpattern</var></code></dt>

  283. <dd><p>When removing sections from the output file, keep sections that match

  284. <var>sectionpattern</var>.

  285. </p>

  286. </dd>

  287. <dt><code>--remove-relocations=<var>sectionpattern</var></code></dt>

  288. <dd><p>Remove non-dynamic relocations from the output file for any section

  289. matching <var>sectionpattern</var>.  This option may be given more than

  290. once.  Note that using this option inappropriately may make the output

  291. file unusable, and attempting to remove a dynamic relocation section

  292. such as &lsquo;<samp>.rela.plt</samp>&rsquo; from an executable or shared library with

  293. <samp>--remove-relocations=.plt</samp> will not work.  Wildcard characters

  294. are accepted in <var>sectionpattern</var>.

  295. For example:

  296. </p>

  297. <div class="smallexample">

  298. <pre class="smallexample">  --remove-relocations=.text.*

  299. </pre></div>

  300. 

  301. <p>will remove the relocations for all sections matching the pattern

  302. &rsquo;.text.*&rsquo;.

  303. </p>

  304. <p>If the first character of <var>sectionpattern</var> is the exclamation

  305. point (!) then matching sections will not have their relocation

  306. removed even if an earlier use of <samp>--remove-relocations</samp> on the

  307. same command line would otherwise cause the relocations to be removed.

  308. For example:

  309. </p>

  310. <div class="smallexample">

  311. <pre class="smallexample">  --remove-relocations=.text.* --remove-relocations=!.text.foo

  312. </pre></div>

  313. 

  314. <p>will remove all relocations for sections matching the pattern

  315. &rsquo;.text.*&rsquo;, but will not remove relocations for the section

  316. &rsquo;.text.foo&rsquo;.

  317. </p>

  318. </dd>

  319. <dt><code>-S</code></dt>

  320. <dt><code>--strip-all</code></dt>

  321. <dd><p>Do not copy relocation and symbol information from the source file.

  322. </p>

  323. </dd>

  324. <dt><code>-g</code></dt>

  325. <dt><code>--strip-debug</code></dt>

  326. <dd><p>Do not copy debugging symbols or sections from the source file.

  327. </p>

  328. </dd>

  329. <dt><code>--strip-unneeded</code></dt>

  330. <dd><p>Strip all symbols that are not needed for relocation processing.

  331. </p>

  332. </dd>

  333. <dt><code>-K <var>symbolname</var></code></dt>

  334. <dt><code>--keep-symbol=<var>symbolname</var></code></dt>

  335. <dd><p>When stripping symbols, keep symbol <var>symbolname</var> even if it would

  336. normally be stripped.  This option may be given more than once.

  337. </p>

  338. </dd>

  339. <dt><code>-N <var>symbolname</var></code></dt>

  340. <dt><code>--strip-symbol=<var>symbolname</var></code></dt>

  341. <dd><p>Do not copy symbol <var>symbolname</var> from the source file.  This option

  342. may be given more than once.

  343. </p>

  344. </dd>

  345. <dt><code>--strip-unneeded-symbol=<var>symbolname</var></code></dt>

  346. <dd><p>Do not copy symbol <var>symbolname</var> from the source file unless it is needed

  347. by a relocation.  This option may be given more than once.

  348. </p>

  349. </dd>

  350. <dt><code>-G <var>symbolname</var></code></dt>

  351. <dt><code>--keep-global-symbol=<var>symbolname</var></code></dt>

  352. <dd><p>Keep only symbol <var>symbolname</var> global.  Make all other symbols local

  353. to the file, so that they are not visible externally.  This option may

  354. be given more than once.  Note: this option cannot be used in

  355. conjunction with the <samp>--globalize-symbol</samp> or

  356. <samp>--globalize-symbols</samp> options.

  357. </p>

  358. </dd>

  359. <dt><code>--localize-hidden</code></dt>

  360. <dd><p>In an ELF object, mark all symbols that have hidden or internal visibility

  361. as local.  This option applies on top of symbol-specific localization options

  362. such as <samp>-L</samp>.

  363. </p>

  364. </dd>

  365. <dt><code>-L <var>symbolname</var></code></dt>

  366. <dt><code>--localize-symbol=<var>symbolname</var></code></dt>

  367. <dd><p>Convert a global or weak symbol called <var>symbolname</var> into a local

  368. symbol, so that it is not visible externally.  This option may be

  369. given more than once.  Note - unique symbols are not converted.

  370. </p>

  371. </dd>

  372. <dt><code>-W <var>symbolname</var></code></dt>

  373. <dt><code>--weaken-symbol=<var>symbolname</var></code></dt>

  374. <dd><p>Make symbol <var>symbolname</var> weak. This option may be given more than once.

  375. </p>

  376. </dd>

  377. <dt><code>--globalize-symbol=<var>symbolname</var></code></dt>

  378. <dd><p>Give symbol <var>symbolname</var> global scoping so that it is visible

  379. outside of the file in which it is defined.  This option may be given

  380. more than once.  Note: this option cannot be used in conjunction with

  381. the <samp>-G</samp> or <samp>--keep-global-symbol</samp> options.

  382. </p>

  383. </dd>

  384. <dt><code>-w</code></dt>

  385. <dt><code>--wildcard</code></dt>

  386. <dd><p>Permit regular expressions in <var>symbolname</var>s used in other command

  387. line options.  The question mark (?), asterisk (*), backslash (\) and

  388. square brackets ([]) operators can be used anywhere in the symbol

  389. name.  If the first character of the symbol name is the exclamation

  390. point (!) then the sense of the switch is reversed for that symbol.

  391. For example:

  392. </p>

  393. <div class="smallexample">

  394. <pre class="smallexample">  -w -W !foo -W fo*

  395. </pre></div>

  396. 

  397. <p>would cause objcopy to weaken all symbols that start with &ldquo;fo&rdquo;

  398. except for the symbol &ldquo;foo&rdquo;.

  399. </p>

  400. </dd>

  401. <dt><code>-x</code></dt>

  402. <dt><code>--discard-all</code></dt>

  403. <dd><p>Do not copy non-global symbols from the source file.

  404. </p>

  405. </dd>

  406. <dt><code>-X</code></dt>

  407. <dt><code>--discard-locals</code></dt>

  408. <dd><p>Do not copy compiler-generated local symbols.

  409. (These usually start with &lsquo;<samp>L</samp>&rsquo; or &lsquo;<samp>.</samp>&rsquo;.)

  410. </p>

  411. </dd>

  412. <dt><code>-b <var>byte</var></code></dt>

  413. <dt><code>--byte=<var>byte</var></code></dt>

  414. <dd><p>If interleaving has been enabled via the <samp>--interleave</samp> option

  415. then start the range of bytes to keep at the <var>byte</var>th byte.

  416. <var>byte</var> can be in the range from 0 to <var>breadth</var>-1, where

  417. <var>breadth</var> is the value given by the <samp>--interleave</samp> option.

  418. </p>

  419. </dd>

  420. <dt><code>-i [<var>breadth</var>]</code></dt>

  421. <dt><code>--interleave[=<var>breadth</var>]</code></dt>

  422. <dd><p>Only copy a range out of every <var>breadth</var> bytes.  (Header data is

  423. not affected).  Select which byte in the range begins the copy with

  424. the <samp>--byte</samp> option.  Select the width of the range with the

  425. <samp>--interleave-width</samp> option.

  426. </p>

  427. <p>This option is useful for creating files to program <small>ROM</small>.  It is

  428. typically used with an <code>srec</code> output target.  Note that

  429. <code>objcopy</code> will complain if you do not specify the

  430. <samp>--byte</samp> option as well.

  431. </p>

  432. <p>The default interleave breadth is 4, so with <samp>--byte</samp> set to 0,

  433. <code>objcopy</code> would copy the first byte out of every four bytes

  434. from the input to the output.

  435. </p>

  436. </dd>

  437. <dt><code>--interleave-width=<var>width</var></code></dt>

  438. <dd><p>When used with the <samp>--interleave</samp> option, copy <var>width</var>

  439. bytes at a time.  The start of the range of bytes to be copied is set

  440. by the <samp>--byte</samp> option, and the extent of the range is set with

  441. the <samp>--interleave</samp> option.

  442. </p>

  443. <p>The default value for this option is 1.  The value of <var>width</var> plus

  444. the <var>byte</var> value set by the <samp>--byte</samp> option must not exceed

  445. the interleave breadth set by the <samp>--interleave</samp> option.

  446. </p>

  447. <p>This option can be used to create images for two 16-bit flashes interleaved

  448. in a 32-bit bus by passing <samp>-b 0 -i 4 --interleave-width=2</samp>

  449. and <samp>-b 2 -i 4 --interleave-width=2</samp> to two <code>objcopy</code>

  450. commands.  If the input was &rsquo;12345678&rsquo; then the outputs would be

  451. &rsquo;1256&rsquo; and &rsquo;3478&rsquo; respectively.

  452. </p>

  453. </dd>

  454. <dt><code>-p</code></dt>

  455. <dt><code>--preserve-dates</code></dt>

  456. <dd><p>Set the access and modification dates of the output file to be the same

  457. as those of the input file.

  458. </p>

  459. </dd>

  460. <dt><code>-D</code></dt>

  461. <dt><code>--enable-deterministic-archives</code></dt>

  462. <dd><a name="index-deterministic-archives-2"></a>

  463. <a name="index-_002d_002denable_002ddeterministic_002darchives-2"></a>

  464. <p>Operate in <em>deterministic</em> mode.  When copying archive members

  465. and writing the archive index, use zero for UIDs, GIDs, timestamps,

  466. and use consistent file modes for all files.

  467. </p>

  468. <p>If <samp>binutils</samp> was configured with

  469. <samp>--enable-deterministic-archives</samp>, then this mode is on by default.

  470. It can be disabled with the &lsquo;<samp>-U</samp>&rsquo; option, below.

  471. </p>

  472. </dd>

  473. <dt><code>-U</code></dt>

  474. <dt><code>--disable-deterministic-archives</code></dt>

  475. <dd><a name="index-deterministic-archives-3"></a>

  476. <a name="index-_002d_002denable_002ddeterministic_002darchives-3"></a>

  477. <p>Do <em>not</em> operate in <em>deterministic</em> mode.  This is the

  478. inverse of the <samp>-D</samp> option, above: when copying archive members

  479. and writing the archive index, use their actual UID, GID, timestamp,

  480. and file mode values.

  481. </p>

  482. <p>This is the default unless <samp>binutils</samp> was configured with

  483. <samp>--enable-deterministic-archives</samp>.

  484. </p>

  485. </dd>

  486. <dt><code>--debugging</code></dt>

  487. <dd><p>Convert debugging information, if possible.  This is not the default

  488. because only certain debugging formats are supported, and the

  489. conversion process can be time consuming.

  490. </p>

  491. </dd>

  492. <dt><code>--gap-fill <var>val</var></code></dt>

  493. <dd><p>Fill gaps between sections with <var>val</var>.  This operation applies to

  494. the <em>load address</em> (LMA) of the sections.  It is done by increasing

  495. the size of the section with the lower address, and filling in the extra

  496. space created with <var>val</var>.

  497. </p>

  498. </dd>

  499. <dt><code>--pad-to <var>address</var></code></dt>

  500. <dd><p>Pad the output file up to the load address <var>address</var>.  This is

  501. done by increasing the size of the last section.  The extra space is

  502. filled in with the value specified by <samp>--gap-fill</samp> (default zero).

  503. </p>

  504. </dd>

  505. <dt><code>--set-start <var>val</var></code></dt>

  506. <dd><p>Set the start address (also known as the entry address) of the new

  507. file to <var>val</var>.  Not all object file formats support setting the

  508. start address.

  509. </p>

  510. </dd>

  511. <dt><code>--change-start <var>incr</var></code></dt>

  512. <dt><code>--adjust-start <var>incr</var></code></dt>

  513. <dd><a name="index-changing-start-address"></a>

  514. <p>Change the start address (also known as the entry address) by adding

  515. <var>incr</var>.  Not all object file formats support setting the start

  516. address.

  517. </p>

  518. </dd>

  519. <dt><code>--change-addresses <var>incr</var></code></dt>

  520. <dt><code>--adjust-vma <var>incr</var></code></dt>

  521. <dd><a name="index-changing-object-addresses"></a>

  522. <p>Change the VMA and LMA addresses of all sections, as well as the start

  523. address, by adding <var>incr</var>.  Some object file formats do not permit

  524. section addresses to be changed arbitrarily.  Note that this does not

  525. relocate the sections; if the program expects sections to be loaded at a

  526. certain address, and this option is used to change the sections such

  527. that they are loaded at a different address, the program may fail.

  528. </p>

  529. </dd>

  530. <dt><code>--change-section-address <var>sectionpattern</var>{=,+,-}<var>val</var></code></dt>

  531. <dt><code>--adjust-section-vma <var>sectionpattern</var>{=,+,-}<var>val</var></code></dt>

  532. <dd><a name="index-changing-section-address"></a>

  533. <p>Set or change both the VMA address and the LMA address of any section

  534. matching <var>sectionpattern</var>.  If &lsquo;<samp>=</samp>&rsquo; is used, the section

  535. address is set to <var>val</var>.  Otherwise, <var>val</var> is added to or

  536. subtracted from the section address.  See the comments under

  537. <samp>--change-addresses</samp>, above. If <var>sectionpattern</var> does not

  538. match any sections in the input file, a warning will be issued, unless

  539. <samp>--no-change-warnings</samp> is used.

  540. </p>

  541. </dd>

  542. <dt><code>--change-section-lma <var>sectionpattern</var>{=,+,-}<var>val</var></code></dt>

  543. <dd><a name="index-changing-section-LMA"></a>

  544. <p>Set or change the LMA address of any sections matching

  545. <var>sectionpattern</var>.  The LMA address is the address where the

  546. section will be loaded into memory at program load time.  Normally

  547. this is the same as the VMA address, which is the address of the

  548. section at program run time, but on some systems, especially those

  549. where a program is held in ROM, the two can be different.  If &lsquo;<samp>=</samp>&rsquo;

  550. is used, the section address is set to <var>val</var>.  Otherwise,

  551. <var>val</var> is added to or subtracted from the section address.  See the

  552. comments under <samp>--change-addresses</samp>, above.  If

  553. <var>sectionpattern</var> does not match any sections in the input file, a

  554. warning will be issued, unless <samp>--no-change-warnings</samp> is used.

  555. </p>

  556. </dd>

  557. <dt><code>--change-section-vma <var>sectionpattern</var>{=,+,-}<var>val</var></code></dt>

  558. <dd><a name="index-changing-section-VMA"></a>

  559. <p>Set or change the VMA address of any section matching

  560. <var>sectionpattern</var>.  The VMA address is the address where the

  561. section will be located once the program has started executing.

  562. Normally this is the same as the LMA address, which is the address

  563. where the section will be loaded into memory, but on some systems,

  564. especially those where a program is held in ROM, the two can be

  565. different.  If &lsquo;<samp>=</samp>&rsquo; is used, the section address is set to

  566. <var>val</var>.  Otherwise, <var>val</var> is added to or subtracted from the

  567. section address.  See the comments under <samp>--change-addresses</samp>,

  568. above.  If <var>sectionpattern</var> does not match any sections in the

  569. input file, a warning will be issued, unless

  570. <samp>--no-change-warnings</samp> is used.

  571. </p>

  572. </dd>

  573. <dt><code>--change-warnings</code></dt>

  574. <dt><code>--adjust-warnings</code></dt>

  575. <dd><p>If <samp>--change-section-address</samp> or <samp>--change-section-lma</samp> or

  576. <samp>--change-section-vma</samp> is used, and the section pattern does not

  577. match any sections, issue a warning.  This is the default.

  578. </p>

  579. </dd>

  580. <dt><code>--no-change-warnings</code></dt>

  581. <dt><code>--no-adjust-warnings</code></dt>

  582. <dd><p>Do not issue a warning if <samp>--change-section-address</samp> or

  583. <samp>--adjust-section-lma</samp> or <samp>--adjust-section-vma</samp> is used, even

  584. if the section pattern does not match any sections.

  585. </p>

  586. </dd>

  587. <dt><code>--set-section-flags <var>sectionpattern</var>=<var>flags</var></code></dt>

  588. <dd><p>Set the flags for any sections matching <var>sectionpattern</var>.  The

  589. <var>flags</var> argument is a comma separated string of flag names.  The

  590. recognized names are &lsquo;<samp>alloc</samp>&rsquo;, &lsquo;<samp>contents</samp>&rsquo;, &lsquo;<samp>load</samp>&rsquo;,

  591. &lsquo;<samp>noload</samp>&rsquo;, &lsquo;<samp>readonly</samp>&rsquo;, &lsquo;<samp>code</samp>&rsquo;, &lsquo;<samp>data</samp>&rsquo;, &lsquo;<samp>rom</samp>&rsquo;,

  592. &lsquo;<samp>exclude</samp>&rsquo;, &lsquo;<samp>share</samp>&rsquo;, and &lsquo;<samp>debug</samp>&rsquo;.  You can set the

  593. &lsquo;<samp>contents</samp>&rsquo; flag for a section which does not have contents, but it

  594. is not meaningful to clear the &lsquo;<samp>contents</samp>&rsquo; flag of a section which

  595. does have contents&ndash;just remove the section instead.  Not all flags are

  596. meaningful for all object file formats.  In particular the

  597. &lsquo;<samp>share</samp>&rsquo; flag is only meaningful for COFF format files and not for

  598. ELF format files.

  599. </p>

  600. </dd>

  601. <dt><code>--set-section-alignment <var>sectionpattern</var>=<var>align</var></code></dt>

  602. <dd><p>Set the alignment for any sections matching <var>sectionpattern</var>.

  603. <var>align</var> specifies the alignment in bytes and must be a power of

  604. two, i.e. 1, 2, 4, 8&hellip;. 

  605. </p>

  606. </dd>

  607. <dt><code>--add-section <var>sectionname</var>=<var>filename</var></code></dt>

  608. <dd><p>Add a new section named <var>sectionname</var> while copying the file.  The

  609. contents of the new section are taken from the file <var>filename</var>.  The

  610. size of the section will be the size of the file.  This option only

  611. works on file formats which can support sections with arbitrary names.

  612. Note - it may be necessary to use the <samp>--set-section-flags</samp>

  613. option to set the attributes of the newly created section.

  614. </p>

  615. </dd>

  616. <dt><code>--dump-section <var>sectionname</var>=<var>filename</var></code></dt>

  617. <dd><p>Place the contents of section named <var>sectionname</var> into the file

  618. <var>filename</var>, overwriting any contents that may have been there

  619. previously.  This option is the inverse of <samp>--add-section</samp>.

  620. This option is similar to the <samp>--only-section</samp> option except

  621. that it does not create a formatted file, it just dumps the contents

  622. as raw binary data, without applying any relocations.  The option can

  623. be specified more than once.

  624. </p>

  625. </dd>

  626. <dt><code>--update-section <var>sectionname</var>=<var>filename</var></code></dt>

  627. <dd><p>Replace the existing contents of a section named <var>sectionname</var>

  628. with the contents of file <var>filename</var>.  The size of the section

  629. will be adjusted to the size of the file.  The section flags for

  630. <var>sectionname</var> will be unchanged.  For ELF format files the section

  631. to segment mapping will also remain unchanged, something which is not

  632. possible using <samp>--remove-section</samp> followed by

  633. <samp>--add-section</samp>.  The option can be specified more than once.

  634. </p>

  635. <p>Note - it is possible to use <samp>--rename-section</samp> and

  636. <samp>--update-section</samp> to both update and rename a section from one

  637. command line.  In this case, pass the original section name to

  638. <samp>--update-section</samp>, and the original and new section names to

  639. <samp>--rename-section</samp>.

  640. </p>

  641. </dd>

  642. <dt><code>--add-symbol <var>name</var>=[<var>section</var>:]<var>value</var>[,<var>flags</var>]</code></dt>

  643. <dd><p>Add a new symbol named <var>name</var> while copying the file.  This option may be

  644. specified multiple times.  If the <var>section</var> is given, the symbol will be

  645. associated with and relative to that section, otherwise it will be an ABS

  646. symbol.  Specifying an undefined section will result in a fatal error.  There

  647. is no check for the value, it will be taken as specified.  Symbol flags can

  648. be specified and not all flags will be meaningful for all object file

  649. formats.  By default, the symbol will be global.  The special flag

  650. &rsquo;before=<var>othersym</var>&rsquo; will insert the new symbol in front of the specified

  651. <var>othersym</var>, otherwise the symbol(s) will be added at the end of the

  652. symbol table in the order they appear.

  653. </p>

  654. </dd>

  655. <dt><code>--rename-section <var>oldname</var>=<var>newname</var>[,<var>flags</var>]</code></dt>

  656. <dd><p>Rename a section from <var>oldname</var> to <var>newname</var>, optionally

  657. changing the section&rsquo;s flags to <var>flags</var> in the process.  This has

  658. the advantage over using a linker script to perform the rename in that

  659. the output stays as an object file and does not become a linked

  660. executable.  This option accepts the same set of flags as the

  661. <samp>--sect-section-flags</samp> option.

  662. </p>

  663. <p>This option is particularly helpful when the input format is binary,

  664. since this will always create a section called .data.  If for example,

  665. you wanted instead to create a section called .rodata containing binary

  666. data you could use the following command line to achieve it:

  667. </p>

  668. <div class="smallexample">

  669. <pre class="smallexample">  objcopy -I binary -O &lt;output_format&gt; -B &lt;architecture&gt; \

  670.    --rename-section .data=.rodata,alloc,load,readonly,data,contents \

  671.    &lt;input_binary_file&gt; &lt;output_object_file&gt;

  672. </pre></div>

  673. 

  674. </dd>

  675. <dt><code>--long-section-names {enable,disable,keep}</code></dt>

  676. <dd><p>Controls the handling of long section names when processing <code>COFF</code>

  677. and <code>PE-COFF</code> object formats.  The default behaviour, &lsquo;<samp>keep</samp>&rsquo;,

  678. is to preserve long section names if any are present in the input file.

  679. The &lsquo;<samp>enable</samp>&rsquo; and &lsquo;<samp>disable</samp>&rsquo; options forcibly enable or disable

  680. the use of long section names in the output object; when &lsquo;<samp>disable</samp>&rsquo;

  681. is in effect, any long section names in the input object will be truncated.

  682. The &lsquo;<samp>enable</samp>&rsquo; option will only emit long section names if any are

  683. present in the inputs; this is mostly the same as &lsquo;<samp>keep</samp>&rsquo;, but it

  684. is left undefined whether the &lsquo;<samp>enable</samp>&rsquo; option might force the

  685. creation of an empty string table in the output file.

  686. </p>

  687. </dd>

  688. <dt><code>--change-leading-char</code></dt>

  689. <dd><p>Some object file formats use special characters at the start of

  690. symbols.  The most common such character is underscore, which compilers

  691. often add before every symbol.  This option tells <code>objcopy</code> to

  692. change the leading character of every symbol when it converts between

  693. object file formats.  If the object file formats use the same leading

  694. character, this option has no effect.  Otherwise, it will add a

  695. character, or remove a character, or change a character, as

  696. appropriate.

  697. </p>

  698. </dd>

  699. <dt><code>--remove-leading-char</code></dt>

  700. <dd><p>If the first character of a global symbol is a special symbol leading

  701. character used by the object file format, remove the character.  The

  702. most common symbol leading character is underscore.  This option will

  703. remove a leading underscore from all global symbols.  This can be useful

  704. if you want to link together objects of different file formats with

  705. different conventions for symbol names.  This is different from

  706. <samp>--change-leading-char</samp> because it always changes the symbol name

  707. when appropriate, regardless of the object file format of the output

  708. file.

  709. </p>

  710. </dd>

  711. <dt><code>--reverse-bytes=<var>num</var></code></dt>

  712. <dd><p>Reverse the bytes in a section with output contents.  A section length must

  713. be evenly divisible by the value given in order for the swap to be able to

  714. take place. Reversing takes place before the interleaving is performed.

  715. </p>

  716. <p>This option is used typically in generating ROM images for problematic

  717. target systems.  For example, on some target boards, the 32-bit words

  718. fetched from 8-bit ROMs are re-assembled in little-endian byte order

  719. regardless of the CPU byte order.  Depending on the programming model, the

  720. endianness of the ROM may need to be modified.

  721. </p>

  722. <p>Consider a simple file with a section containing the following eight

  723. bytes:  <code>12345678</code>.

  724. </p>

  725. <p>Using &lsquo;<samp>--reverse-bytes=2</samp>&rsquo; for the above example, the bytes in the

  726. output file would be ordered <code>21436587</code>.

  727. </p>

  728. <p>Using &lsquo;<samp>--reverse-bytes=4</samp>&rsquo; for the above example, the bytes in the

  729. output file would be ordered <code>43218765</code>.

  730. </p>

  731. <p>By using &lsquo;<samp>--reverse-bytes=2</samp>&rsquo; for the above example, followed by

  732. &lsquo;<samp>--reverse-bytes=4</samp>&rsquo; on the output file, the bytes in the second

  733. output file would be ordered <code>34127856</code>.

  734. </p>

  735. </dd>

  736. <dt><code>--srec-len=<var>ival</var></code></dt>

  737. <dd><p>Meaningful only for srec output.  Set the maximum length of the Srecords

  738. being produced to <var>ival</var>.  This length covers both address, data and

  739. crc fields.

  740. </p>

  741. </dd>

  742. <dt><code>--srec-forceS3</code></dt>

  743. <dd><p>Meaningful only for srec output.  Avoid generation of S1/S2 records,

  744. creating S3-only record format.

  745. </p>

  746. </dd>

  747. <dt><code>--redefine-sym <var>old</var>=<var>new</var></code></dt>

  748. <dd><p>Change the name of a symbol <var>old</var>, to <var>new</var>.  This can be useful

  749. when one is trying link two things together for which you have no

  750. source, and there are name collisions.

  751. </p>

  752. </dd>

  753. <dt><code>--redefine-syms=<var>filename</var></code></dt>

  754. <dd><p>Apply <samp>--redefine-sym</samp> to each symbol pair &quot;<var>old</var> <var>new</var>&quot;

  755. listed in the file <var>filename</var>.  <var>filename</var> is simply a flat file,

  756. with one symbol pair per line.  Line comments may be introduced by the hash

  757. character.  This option may be given more than once.

  758. </p>

  759. </dd>

  760. <dt><code>--weaken</code></dt>

  761. <dd><p>Change all global symbols in the file to be weak.  This can be useful

  762. when building an object which will be linked against other objects using

  763. the <samp>-R</samp> option to the linker.  This option is only effective when

  764. using an object file format which supports weak symbols.

  765. </p>

  766. </dd>

  767. <dt><code>--keep-symbols=<var>filename</var></code></dt>

  768. <dd><p>Apply <samp>--keep-symbol</samp> option to each symbol listed in the file

  769. <var>filename</var>.  <var>filename</var> is simply a flat file, with one symbol

  770. name per line.  Line comments may be introduced by the hash character.

  771. This option may be given more than once.

  772. </p>

  773. </dd>

  774. <dt><code>--strip-symbols=<var>filename</var></code></dt>

  775. <dd><p>Apply <samp>--strip-symbol</samp> option to each symbol listed in the file

  776. <var>filename</var>.  <var>filename</var> is simply a flat file, with one symbol

  777. name per line.  Line comments may be introduced by the hash character.

  778. This option may be given more than once.

  779. </p>

  780. </dd>

  781. <dt><code>--strip-unneeded-symbols=<var>filename</var></code></dt>

  782. <dd><p>Apply <samp>--strip-unneeded-symbol</samp> option to each symbol listed in

  783. the file <var>filename</var>.  <var>filename</var> is simply a flat file, with one

  784. symbol name per line.  Line comments may be introduced by the hash

  785. character.  This option may be given more than once.

  786. </p>

  787. </dd>

  788. <dt><code>--keep-global-symbols=<var>filename</var></code></dt>

  789. <dd><p>Apply <samp>--keep-global-symbol</samp> option to each symbol listed in the

  790. file <var>filename</var>.  <var>filename</var> is simply a flat file, with one

  791. symbol name per line.  Line comments may be introduced by the hash

  792. character.  This option may be given more than once.

  793. </p>

  794. </dd>

  795. <dt><code>--localize-symbols=<var>filename</var></code></dt>

  796. <dd><p>Apply <samp>--localize-symbol</samp> option to each symbol listed in the file

  797. <var>filename</var>.  <var>filename</var> is simply a flat file, with one symbol

  798. name per line.  Line comments may be introduced by the hash character.

  799. This option may be given more than once.

  800. </p>

  801. </dd>

  802. <dt><code>--globalize-symbols=<var>filename</var></code></dt>

  803. <dd><p>Apply <samp>--globalize-symbol</samp> option to each symbol listed in the file

  804. <var>filename</var>.  <var>filename</var> is simply a flat file, with one symbol

  805. name per line.  Line comments may be introduced by the hash character.

  806. This option may be given more than once.  Note: this option cannot be

  807. used in conjunction with the <samp>-G</samp> or <samp>--keep-global-symbol</samp>

  808. options.

  809. </p>

  810. </dd>

  811. <dt><code>--weaken-symbols=<var>filename</var></code></dt>

  812. <dd><p>Apply <samp>--weaken-symbol</samp> option to each symbol listed in the file

  813. <var>filename</var>.  <var>filename</var> is simply a flat file, with one symbol

  814. name per line.  Line comments may be introduced by the hash character.

  815. This option may be given more than once.

  816. </p>

  817. </dd>

  818. <dt><code>--alt-machine-code=<var>index</var></code></dt>

  819. <dd><p>If the output architecture has alternate machine codes, use the

  820. <var>index</var>th code instead of the default one.  This is useful in case

  821. a machine is assigned an official code and the tool-chain adopts the

  822. new code, but other applications still depend on the original code

  823. being used.  For ELF based architectures if the <var>index</var>

  824. alternative does not exist then the value is treated as an absolute

  825. number to be stored in the e_machine field of the ELF header.

  826. </p>

  827. </dd>

  828. <dt><code>--writable-text</code></dt>

  829. <dd><p>Mark the output text as writable.  This option isn&rsquo;t meaningful for all

  830. object file formats.

  831. </p>

  832. </dd>

  833. <dt><code>--readonly-text</code></dt>

  834. <dd><p>Make the output text write protected.  This option isn&rsquo;t meaningful for all

  835. object file formats.

  836. </p>

  837. </dd>

  838. <dt><code>--pure</code></dt>

  839. <dd><p>Mark the output file as demand paged.  This option isn&rsquo;t meaningful for all

  840. object file formats.

  841. </p>

  842. </dd>

  843. <dt><code>--impure</code></dt>

  844. <dd><p>Mark the output file as impure.  This option isn&rsquo;t meaningful for all

  845. object file formats.

  846. </p>

  847. </dd>

  848. <dt><code>--prefix-symbols=<var>string</var></code></dt>

  849. <dd><p>Prefix all symbols in the output file with <var>string</var>.

  850. </p>

  851. </dd>

  852. <dt><code>--prefix-sections=<var>string</var></code></dt>

  853. <dd><p>Prefix all section names in the output file with <var>string</var>.

  854. </p>

  855. </dd>

  856. <dt><code>--prefix-alloc-sections=<var>string</var></code></dt>

  857. <dd><p>Prefix all the names of all allocated sections in the output file with

  858. <var>string</var>.

  859. </p>

  860. </dd>

  861. <dt><code>--add-gnu-debuglink=<var>path-to-file</var></code></dt>

  862. <dd><p>Creates a .gnu_debuglink section which contains a reference to

  863. <var>path-to-file</var> and adds it to the output file.  Note: the file at

  864. <var>path-to-file</var> must exist.  Part of the process of adding the

  865. .gnu_debuglink section involves embedding a checksum of the contents

  866. of the debug info file into the section.

  867. </p>

  868. <p>If the debug info file is built in one location but it is going to be

  869. installed at a later time into a different location then do not use

  870. the path to the installed location.  The <samp>--add-gnu-debuglink</samp>

  871. option will fail because the installed file does not exist yet.

  872. Instead put the debug info file in the current directory and use the

  873. <samp>--add-gnu-debuglink</samp> option without any directory components,

  874. like this:

  875. </p>

  876. <div class="smallexample">

  877. <pre class="smallexample"> objcopy --add-gnu-debuglink=foo.debug

  878. </pre></div>

  879. 

  880. <p>At debug time the debugger will attempt to look for the separate debug

  881. info file in a set of known locations.  The exact set of these

  882. locations varies depending upon the distribution being used, but it

  883. typically includes:

  884. </p>

  885. <dl compact="compact">

  886. <dt><code>* The same directory as the executable.</code></dt>

  887. <dt><code>* A sub-directory of the directory containing the executable</code></dt>

  888. <dd><p>called .debug

  889. </p>

  890. </dd>

  891. <dt><code>* A global debug directory such as /usr/lib/debug.</code></dt>

  892. </dl>

  893. 

  894. <p>As long as the debug info file has been installed into one of these

  895. locations before the debugger is run everything should work

  896. correctly.

  897. </p>

  898. </dd>

  899. <dt><code>--keep-file-symbols</code></dt>

  900. <dd><p>When stripping a file, perhaps with <samp>--strip-debug</samp> or

  901. <samp>--strip-unneeded</samp>, retain any symbols specifying source file names,

  902. which would otherwise get stripped.

  903. </p>

  904. </dd>

  905. <dt><code>--only-keep-debug</code></dt>

  906. <dd><p>Strip a file, removing contents of any sections that would not be

  907. stripped by <samp>--strip-debug</samp> and leaving the debugging sections

  908. intact.  In ELF files, this preserves all note sections in the output.

  909. </p>

  910. <p>Note - the section headers of the stripped sections are preserved,

  911. including their sizes, but the contents of the section are discarded.

  912. The section headers are preserved so that other tools can match up the

  913. debuginfo file with the real executable, even if that executable has

  914. been relocated to a different address space.

  915. </p>

  916. <p>The intention is that this option will be used in conjunction with

  917. <samp>--add-gnu-debuglink</samp> to create a two part executable.  One a

  918. stripped binary which will occupy less space in RAM and in a

  919. distribution and the second a debugging information file which is only

  920. needed if debugging abilities are required.  The suggested procedure

  921. to create these files is as follows:

  922. </p>

  923. <ol>

  924. <li> Link the executable as normal.  Assuming that it is called

  925. <code>foo</code> then...

  926. </li><li> Run <code>objcopy --only-keep-debug foo foo.dbg</code> to

  927. create a file containing the debugging info.

  928. </li><li> Run <code>objcopy --strip-debug foo</code> to create a

  929. stripped executable.

  930. </li><li> Run <code>objcopy --add-gnu-debuglink=foo.dbg foo</code>

  931. to add a link to the debugging info into the stripped executable.

  932. </li></ol>

  933. 

  934. <p>Note&mdash;the choice of <code>.dbg</code> as an extension for the debug info

  935. file is arbitrary.  Also the <code>--only-keep-debug</code> step is

  936. optional.  You could instead do this:

  937. </p>

  938. <ol>

  939. <li> Link the executable as normal.

  940. </li><li> Copy <code>foo</code> to  <code>foo.full</code>

  941. </li><li> Run <code>objcopy --strip-debug foo</code>

  942. </li><li> Run <code>objcopy --add-gnu-debuglink=foo.full foo</code>

  943. </li></ol>

  944. 

  945. <p>i.e., the file pointed to by the <samp>--add-gnu-debuglink</samp> can be the

  946. full executable.  It does not have to be a file created by the

  947. <samp>--only-keep-debug</samp> switch.

  948. </p>

  949. <p>Note&mdash;this switch is only intended for use on fully linked files.  It

  950. does not make sense to use it on object files where the debugging

  951. information may be incomplete.  Besides the gnu_debuglink feature

  952. currently only supports the presence of one filename containing

  953. debugging information, not multiple filenames on a one-per-object-file

  954. basis.

  955. </p>

  956. </dd>

  957. <dt><code>--strip-dwo</code></dt>

  958. <dd><p>Remove the contents of all DWARF .dwo sections, leaving the

  959. remaining debugging sections and all symbols intact.

  960. This option is intended for use by the compiler as part of

  961. the <samp>-gsplit-dwarf</samp> option, which splits debug information

  962. between the .o file and a separate .dwo file.  The compiler

  963. generates all debug information in the same file, then uses

  964. the <samp>--extract-dwo</samp> option to copy the .dwo sections to

  965. the .dwo file, then the <samp>--strip-dwo</samp> option to remove

  966. those sections from the original .o file.

  967. </p>

  968. </dd>

  969. <dt><code>--extract-dwo</code></dt>

  970. <dd><p>Extract the contents of all DWARF .dwo sections.  See the

  971. <samp>--strip-dwo</samp> option for more information.

  972. </p>

  973. </dd>

  974. <dt><code>--file-alignment <var>num</var></code></dt>

  975. <dd><p>Specify the file alignment.  Sections in the file will always begin at

  976. file offsets which are multiples of this number.  This defaults to

  977. 512.

  978. [This option is specific to PE targets.]

  979. </p>

  980. </dd>

  981. <dt><code>--heap <var>reserve</var></code></dt>

  982. <dt><code>--heap <var>reserve</var>,<var>commit</var></code></dt>

  983. <dd><p>Specify the number of bytes of memory to reserve (and optionally commit)

  984. to be used as heap for this program.

  985. [This option is specific to PE targets.]

  986. </p>

  987. </dd>

  988. <dt><code>--image-base <var>value</var></code></dt>

  989. <dd><p>Use <var>value</var> as the base address of your program or dll.  This is

  990. the lowest memory location that will be used when your program or dll

  991. is loaded.  To reduce the need to relocate and improve performance of

  992. your dlls, each should have a unique base address and not overlap any

  993. other dlls.  The default is 0x400000 for executables, and 0x10000000

  994. for dlls.

  995. [This option is specific to PE targets.]

  996. </p>

  997. </dd>

  998. <dt><code>--section-alignment <var>num</var></code></dt>

  999. <dd><p>Sets the section alignment field in the PE header.  Sections in memory

  1000. will always begin at addresses which are a multiple of this number.

  1001. Defaults to 0x1000.

  1002. [This option is specific to PE targets.]

  1003. </p>

  1004. </dd>

  1005. <dt><code>--stack <var>reserve</var></code></dt>

  1006. <dt><code>--stack <var>reserve</var>,<var>commit</var></code></dt>

  1007. <dd><p>Specify the number of bytes of memory to reserve (and optionally commit)

  1008. to be used as stack for this program.

  1009. [This option is specific to PE targets.]

  1010. </p>

  1011. </dd>

  1012. <dt><code>--subsystem <var>which</var></code></dt>

  1013. <dt><code>--subsystem <var>which</var>:<var>major</var></code></dt>

  1014. <dt><code>--subsystem <var>which</var>:<var>major</var>.<var>minor</var></code></dt>

  1015. <dd><p>Specifies the subsystem under which your program will execute.  The

  1016. legal values for <var>which</var> are <code>native</code>, <code>windows</code>,

  1017. <code>console</code>, <code>posix</code>, <code>efi-app</code>, <code>efi-bsd</code>,

  1018. <code>efi-rtd</code>, <code>sal-rtd</code>, and <code>xbox</code>.  You may optionally set

  1019. the subsystem version also.  Numeric values are also accepted for

  1020. <var>which</var>.

  1021. [This option is specific to PE targets.]

  1022. </p>

  1023. </dd>

  1024. <dt><code>--extract-symbol</code></dt>

  1025. <dd><p>Keep the file&rsquo;s section flags and symbols but remove all section data.

  1026. Specifically, the option:

  1027. </p>

  1028. <ul>

  1029. <li> removes the contents of all sections;

  1030. </li><li> sets the size of every section to zero; and

  1031. </li><li> sets the file&rsquo;s start address to zero.

  1032. </li></ul>

  1033. 

  1034. <p>This option is used to build a <samp>.sym</samp> file for a VxWorks kernel.

  1035. It can also be a useful way of reducing the size of a <samp>--just-symbols</samp>

  1036. linker input file.

  1037. </p>

  1038. </dd>

  1039. <dt><code>--compress-debug-sections</code></dt>

  1040. <dd><p>Compress DWARF debug sections using zlib with SHF_COMPRESSED from the

  1041. ELF ABI.  Note - if compression would actually make a section

  1042. <em>larger</em>, then it is not compressed.

  1043. </p>

  1044. </dd>

  1045. <dt><code>--compress-debug-sections=none</code></dt>

  1046. <dt><code>--compress-debug-sections=zlib</code></dt>

  1047. <dt><code>--compress-debug-sections=zlib-gnu</code></dt>

  1048. <dt><code>--compress-debug-sections=zlib-gabi</code></dt>

  1049. <dd><p>For ELF files, these options control how DWARF debug sections are

  1050. compressed.  <samp>--compress-debug-sections=none</samp> is equivalent

  1051. to <samp>--decompress-debug-sections</samp>.

  1052. <samp>--compress-debug-sections=zlib</samp> and

  1053. <samp>--compress-debug-sections=zlib-gabi</samp> are equivalent to

  1054. <samp>--compress-debug-sections</samp>.

  1055. <samp>--compress-debug-sections=zlib-gnu</samp> compresses DWARF debug

  1056. sections using zlib.  The debug sections are renamed to begin with

  1057. &lsquo;<samp>.zdebug</samp>&rsquo; instead of &lsquo;<samp>.debug</samp>&rsquo;.  Note - if compression would

  1058. actually make a section <em>larger</em>, then it is not compressed nor

  1059. renamed.

  1060. </p>

  1061. </dd>

  1062. <dt><code>--decompress-debug-sections</code></dt>

  1063. <dd><p>Decompress DWARF debug sections using zlib.  The original section

  1064. names of the compressed sections are restored.

  1065. </p>

  1066. </dd>

  1067. <dt><code>--elf-stt-common=yes</code></dt>

  1068. <dt><code>--elf-stt-common=no</code></dt>

  1069. <dd><p>For ELF files, these options control whether common symbols should be

  1070. converted to the <code>STT_COMMON</code> or <code>STT_OBJECT</code> type.

  1071. <samp>--elf-stt-common=yes</samp> converts common symbol type to

  1072. <code>STT_COMMON</code>. <samp>--elf-stt-common=no</samp> converts common symbol

  1073. type to <code>STT_OBJECT</code>.

  1074. </p>

  1075. </dd>

  1076. <dt><code>--merge-notes</code></dt>

  1077. <dt><code>--no-merge-notes</code></dt>

  1078. <dd><p>For ELF files, attempt (or do not attempt) to reduce the size of any

  1079. SHT_NOTE type sections by removing duplicate notes.

  1080. </p>

  1081. </dd>

  1082. <dt><code>-V</code></dt>

  1083. <dt><code>--version</code></dt>

  1084. <dd><p>Show the version number of <code>objcopy</code>.

  1085. </p>

  1086. </dd>

  1087. <dt><code>--verilog-data-width=<var>bytes</var></code></dt>

  1088. <dd><p>For Verilog output, this options controls the number of bytes

  1089. converted for each output data element.  The input target controls the

  1090. endianness of the conversion.

  1091. </p>

  1092. </dd>

  1093. <dt><code>-v</code></dt>

  1094. <dt><code>--verbose</code></dt>

  1095. <dd><p>Verbose output: list all object files modified.  In the case of

  1096. archives, &lsquo;<samp>objcopy -V</samp>&rsquo; lists all members of the archive.

  1097. </p>

  1098. </dd>

  1099. <dt><code>--help</code></dt>

  1100. <dd><p>Show a summary of the options to <code>objcopy</code>.

  1101. </p>

  1102. </dd>

  1103. <dt><code>--info</code></dt>

  1104. <dd><p>Display a list showing all architectures and object formats available.

  1105. </p></dd>

  1106. </dl>

  1107. 

  1108. 

  1109. 

  1110. <hr>

  1111. <div class="header">

  1112. <p>

  1113. Next: <a href="objdump.html#objdump" accesskey="n" rel="next">objdump</a>, Previous: <a href="nm.html#nm" accesskey="p" rel="prev">nm</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Binutils-Index.html#Binutils-Index" title="Index" rel="index">Index</a>]</p>

  1114. </div>

  1115. 

  1116. 

  1117. 

  1118. </body>

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