2000-07-26 Jimmy Guo <guo@cup.hp.com>
[deliverable/binutils-gdb.git] / binutils / binutils.texi
CommitLineData
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1\input texinfo @c -*- Texinfo -*-
2@setfilename binutils.info
3@include config.texi
4
5@ifinfo
6@format
7START-INFO-DIR-ENTRY
ad0481cd
AS
8* Binutils: (binutils). The GNU binary utilities.
9* ar: (binutils)ar. Create, modify, and extract from archives
10* nm: (binutils)nm. List symbols from object files
11* objcopy: (binutils)objcopy. Copy and translate object files
12* objdump: (binutils)objdump. Display information from object files
13* ranlib: (binutils)ranlib. Generate index to archive contents
14* readelf: (binutils)readelf. Display the contents of ELF format files.
15* size: (binutils)size. List section sizes and total size
16* strings: (binutils)strings. List printable strings from files
17* strip: (binutils)strip. Discard symbols
18* c++filt: (binutils)c++filt. Filter to demangle encoded C++ symbols
19* cxxfilt: (binutils)c++filt. MS-DOS name for c++filt
20* addr2line: (binutils)addr2line. Convert addresses to file and line
21* nlmconv: (binutils)nlmconv. Converts object code into an NLM
22* windres: (binutils)windres. Manipulate Windows resources
23* dlltool: (binutils)dlltool. Create files needed to build and use DLLs
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24END-INFO-DIR-ENTRY
25@end format
26@end ifinfo
27
28@ifinfo
8f915f68 29Copyright @copyright{} 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000 Free Software Foundation, Inc.
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30
31Permission is granted to make and distribute verbatim copies of
32this manual provided the copyright notice and this permission notice
33are preserved on all copies.
34
35@ignore
36Permission is granted to process this file through TeX and print the
37results, provided the printed document carries a copying permission
38notice identical to this one except for the removal of this paragraph
39(this paragraph not being relevant to the printed manual).
40
41@end ignore
42
43Permission is granted to copy and distribute modified versions of this
44manual under the conditions for verbatim copying, provided also that
45the entire resulting derived work is distributed under the terms of a
46permission notice identical to this one.
47
48Permission is granted to copy and distribute translations of this manual
49into another language, under the above conditions for modified versions.
50@end ifinfo
51
52@synindex ky cp
53@c
54@c This file documents the GNU binary utilities "ar", "ld", "objcopy",
55@c "objdump", "nm", "size", "strings", "strip", "readelf" and "ranlib".
56@c
8f915f68 57@c Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000 Free Software Foundation, Inc.
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58@c
59@c This text may be freely distributed under the terms of the GNU
60@c General Public License.
61@c
62
63@setchapternewpage odd
64@settitle @sc{gnu} Binary Utilities
65@titlepage
66@finalout
67@title The @sc{gnu} Binary Utilities
68@subtitle Version @value{VERSION}
69@sp 1
70@subtitle May 1993
71@author Roland H. Pesch
72@author Jeffrey M. Osier
73@author Cygnus Support
74@page
75
76@tex
77{\parskip=0pt \hfill Cygnus Support\par \hfill
78\TeX{}info \texinfoversion\par }
79@end tex
80
81@vskip 0pt plus 1filll
82Copyright @copyright{} 1991, 92, 93, 94, 95, 96, 97, 1998 Free Software Foundation, Inc.
83
84Permission is granted to make and distribute verbatim copies of
85this manual provided the copyright notice and this permission notice
86are preserved on all copies.
87
88Permission is granted to copy and distribute modified versions of this
89manual under the conditions for verbatim copying, provided also that
90the entire resulting derived work is distributed under the terms of a
91permission notice identical to this one.
92
93Permission is granted to copy and distribute translations of this manual
94into another language, under the above conditions for modified versions.
95@end titlepage
96
97@node Top
98@top Introduction
99
100@cindex version
101This brief manual contains preliminary documentation for the @sc{gnu} binary
102utilities (collectively version @value{VERSION}):
103
104@iftex
105@table @code
106@item ar
107Create, modify, and extract from archives
108
109@item nm
110List symbols from object files
111
112@item objcopy
113Copy and translate object files
114
115@item objdump
116Display information from object files
117
118@item ranlib
119Generate index to archive contents
120
121@item readelf
122Display the contents of ELF format files.
123
124@item size
125List file section sizes and total size
126
127@item strings
128List printable strings from files
129
130@item strip
131Discard symbols
132
133@item c++filt
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134Demangle encoded C++ symbols (on MS-DOS, this program is named
135@code{cxxfilt})
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136
137@item addr2line
138Convert addresses into file names and line numbers
139
140@item nlmconv
141Convert object code into a Netware Loadable Module
142
143@item windres
144Manipulate Windows resources
145
146@item dlltool
147Create the files needed to build and use Dynamic Link Libraries
148@end table
149@end iftex
150
151@menu
152* ar:: Create, modify, and extract from archives
153* nm:: List symbols from object files
154* objcopy:: Copy and translate object files
155* objdump:: Display information from object files
156* ranlib:: Generate index to archive contents
157* readelf:: Display the contents of ELF format files.
158* size:: List section sizes and total size
159* strings:: List printable strings from files
160* strip:: Discard symbols
161* c++filt:: Filter to demangle encoded C++ symbols
9d51cc66 162* cxxfilt: c++filt. MS-DOS name for c++filt
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163* addr2line:: Convert addresses to file and line
164* nlmconv:: Converts object code into an NLM
165* windres:: Manipulate Windows resources
166* dlltool:: Create files needed to build and use DLLs
167* Selecting The Target System:: How these utilities determine the target.
168* Reporting Bugs:: Reporting Bugs
169* Index:: Index
170@end menu
171
172@node ar
173@chapter ar
174
175@kindex ar
176@cindex archives
177@cindex collections of files
178@smallexample
3de39064 179ar [-]@var{p}[@var{mod} [@var{relpos}] [@var{count}]] @var{archive} [@var{member}@dots{}]
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180ar -M [ <mri-script ]
181@end smallexample
182
183The @sc{gnu} @code{ar} program creates, modifies, and extracts from
184archives. An @dfn{archive} is a single file holding a collection of
185other files in a structure that makes it possible to retrieve
186the original individual files (called @dfn{members} of the archive).
187
188The original files' contents, mode (permissions), timestamp, owner, and
189group are preserved in the archive, and can be restored on
190extraction.
191
192@cindex name length
193@sc{gnu} @code{ar} can maintain archives whose members have names of any
194length; however, depending on how @code{ar} is configured on your
195system, a limit on member-name length may be imposed for compatibility
196with archive formats maintained with other tools. If it exists, the
197limit is often 15 characters (typical of formats related to a.out) or 16
198characters (typical of formats related to coff).
199
200@cindex libraries
201@code{ar} is considered a binary utility because archives of this sort
202are most often used as @dfn{libraries} holding commonly needed
203subroutines.
204
205@cindex symbol index
206@code{ar} creates an index to the symbols defined in relocatable
207object modules in the archive when you specify the modifier @samp{s}.
208Once created, this index is updated in the archive whenever @code{ar}
209makes a change to its contents (save for the @samp{q} update operation).
210An archive with such an index speeds up linking to the library, and
211allows routines in the library to call each other without regard to
212their placement in the archive.
213
214You may use @samp{nm -s} or @samp{nm --print-armap} to list this index
215table. If an archive lacks the table, another form of @code{ar} called
216@code{ranlib} can be used to add just the table.
217
218@cindex compatibility, @code{ar}
219@cindex @code{ar} compatibility
220@sc{gnu} @code{ar} is designed to be compatible with two different
221facilities. You can control its activity using command-line options,
222like the different varieties of @code{ar} on Unix systems; or, if you
223specify the single command-line option @samp{-M}, you can control it
224with a script supplied via standard input, like the MRI ``librarian''
225program.
226
227@menu
228* ar cmdline:: Controlling @code{ar} on the command line
229* ar scripts:: Controlling @code{ar} with a script
230@end menu
231
232@page
233@node ar cmdline
234@section Controlling @code{ar} on the command line
235
236@smallexample
3de39064 237ar [-]@var{p}[@var{mod} [@var{relpos}] [@var{count}]] @var{archive} [@var{member}@dots{}]
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238@end smallexample
239
240@cindex Unix compatibility, @code{ar}
241When you use @code{ar} in the Unix style, @code{ar} insists on at least two
242arguments to execute: one keyletter specifying the @emph{operation}
243(optionally accompanied by other keyletters specifying
244@emph{modifiers}), and the archive name to act on.
245
246Most operations can also accept further @var{member} arguments,
247specifying particular files to operate on.
248
249@sc{gnu} @code{ar} allows you to mix the operation code @var{p} and modifier
250flags @var{mod} in any order, within the first command-line argument.
251
252If you wish, you may begin the first command-line argument with a
253dash.
254
255@cindex operations on archive
256The @var{p} keyletter specifies what operation to execute; it may be
257any of the following, but you must specify only one of them:
258
259@table @code
260@item d
261@cindex deleting from archive
262@emph{Delete} modules from the archive. Specify the names of modules to
263be deleted as @var{member}@dots{}; the archive is untouched if you
264specify no files to delete.
265
266If you specify the @samp{v} modifier, @code{ar} lists each module
267as it is deleted.
268
269@item m
270@cindex moving in archive
271Use this operation to @emph{move} members in an archive.
272
273The ordering of members in an archive can make a difference in how
274programs are linked using the library, if a symbol is defined in more
275than one member.
276
277If no modifiers are used with @code{m}, any members you name in the
278@var{member} arguments are moved to the @emph{end} of the archive;
279you can use the @samp{a}, @samp{b}, or @samp{i} modifiers to move them to a
280specified place instead.
281
282@item p
283@cindex printing from archive
284@emph{Print} the specified members of the archive, to the standard
285output file. If the @samp{v} modifier is specified, show the member
286name before copying its contents to standard output.
287
288If you specify no @var{member} arguments, all the files in the archive are
289printed.
290
291@item q
292@cindex quick append to archive
293@emph{Quick append}; Historically, add the files @var{member}@dots{} to the end of
294@var{archive}, without checking for replacement.
295
296The modifiers @samp{a}, @samp{b}, and @samp{i} do @emph{not} affect this
297operation; new members are always placed at the end of the archive.
298
299The modifier @samp{v} makes @code{ar} list each file as it is appended.
300
301Since the point of this operation is speed, the archive's symbol table
302index is not updated, even if it already existed; you can use @samp{ar s} or
303@code{ranlib} explicitly to update the symbol table index.
304
305However, too many different systems assume quick append rebuilds the
306index, so GNU ar implements @code{q} as a synonym for @code{r}.
307
308@item r
309@cindex replacement in archive
310Insert the files @var{member}@dots{} into @var{archive} (with
311@emph{replacement}). This operation differs from @samp{q} in that any
312previously existing members are deleted if their names match those being
313added.
314
315If one of the files named in @var{member}@dots{} does not exist, @code{ar}
316displays an error message, and leaves undisturbed any existing members
317of the archive matching that name.
318
319By default, new members are added at the end of the file; but you may
320use one of the modifiers @samp{a}, @samp{b}, or @samp{i} to request
321placement relative to some existing member.
322
323The modifier @samp{v} used with this operation elicits a line of
324output for each file inserted, along with one of the letters @samp{a} or
325@samp{r} to indicate whether the file was appended (no old member
326deleted) or replaced.
327
328@item t
329@cindex contents of archive
330Display a @emph{table} listing the contents of @var{archive}, or those
331of the files listed in @var{member}@dots{} that are present in the
332archive. Normally only the member name is shown; if you also want to
333see the modes (permissions), timestamp, owner, group, and size, you can
334request that by also specifying the @samp{v} modifier.
335
336If you do not specify a @var{member}, all files in the archive
337are listed.
338
339@cindex repeated names in archive
340@cindex name duplication in archive
341If there is more than one file with the same name (say, @samp{fie}) in
342an archive (say @samp{b.a}), @samp{ar t b.a fie} lists only the
343first instance; to see them all, you must ask for a complete
344listing---in our example, @samp{ar t b.a}.
345@c WRS only; per Gumby, this is implementation-dependent, and in a more
346@c recent case in fact works the other way.
347
348@item x
349@cindex extract from archive
350@emph{Extract} members (named @var{member}) from the archive. You can
351use the @samp{v} modifier with this operation, to request that
352@code{ar} list each name as it extracts it.
353
354If you do not specify a @var{member}, all files in the archive
355are extracted.
356
357@end table
358
359A number of modifiers (@var{mod}) may immediately follow the @var{p}
360keyletter, to specify variations on an operation's behavior:
361
362@table @code
363@item a
364@cindex relative placement in archive
365Add new files @emph{after} an existing member of the
366archive. If you use the modifier @samp{a}, the name of an existing archive
367member must be present as the @var{relpos} argument, before the
368@var{archive} specification.
369
370@item b
371Add new files @emph{before} an existing member of the
372archive. If you use the modifier @samp{b}, the name of an existing archive
373member must be present as the @var{relpos} argument, before the
374@var{archive} specification. (same as @samp{i}).
375
376@item c
377@cindex creating archives
378@emph{Create} the archive. The specified @var{archive} is always
379created if it did not exist, when you request an update. But a warning is
380issued unless you specify in advance that you expect to create it, by
381using this modifier.
382
383@item f
384Truncate names in the archive. @sc{gnu} @code{ar} will normally permit file
385names of any length. This will cause it to create archives which are
386not compatible with the native @code{ar} program on some systems. If
387this is a concern, the @samp{f} modifier may be used to truncate file
388names when putting them in the archive.
389
390@item i
391Insert new files @emph{before} an existing member of the
392archive. If you use the modifier @samp{i}, the name of an existing archive
393member must be present as the @var{relpos} argument, before the
394@var{archive} specification. (same as @samp{b}).
395
396@item l
397This modifier is accepted but not used.
398@c whaffor ar l modifier??? presumably compat; with
399@c what???---doc@@cygnus.com, 25jan91
400
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401@item N
402Uses the @var{count} parameter. This is used if there are multiple
403entries in the archive with the same name. Extract or delete instance
404@var{count} of the given name from the archive.
405
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406@item o
407@cindex dates in archive
408Preserve the @emph{original} dates of members when extracting them. If
409you do not specify this modifier, files extracted from the archive
410are stamped with the time of extraction.
411
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412@item P
413Use the full path name when matching names in the archive. @sc{gnu}
414@code{ar} can not create an archive with a full path name (such archives
415are not POSIX complaint), but other archive creators can. This option
416will cause @sc{gnu} @code{ar} to match file names using a complete path
417name, which can be convenient when extracting a single file from an
418archive created by another tool.
419
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420@item s
421@cindex writing archive index
422Write an object-file index into the archive, or update an existing one,
423even if no other change is made to the archive. You may use this modifier
424flag either with any operation, or alone. Running @samp{ar s} on an
425archive is equivalent to running @samp{ranlib} on it.
426
427@item S
428@cindex not writing archive index
429Do not generate an archive symbol table. This can speed up building a
430large library in several steps. The resulting archive can not be used
431with the linker. In order to build a symbol table, you must omit the
432@samp{S} modifier on the last execution of @samp{ar}, or you must run
433@samp{ranlib} on the archive.
434
435@item u
436@cindex updating an archive
437Normally, @samp{ar r}@dots{} inserts all files
438listed into the archive. If you would like to insert @emph{only} those
439of the files you list that are newer than existing members of the same
440names, use this modifier. The @samp{u} modifier is allowed only for the
441operation @samp{r} (replace). In particular, the combination @samp{qu} is
442not allowed, since checking the timestamps would lose any speed
443advantage from the operation @samp{q}.
444
445@item v
446This modifier requests the @emph{verbose} version of an operation. Many
447operations display additional information, such as filenames processed,
448when the modifier @samp{v} is appended.
449
450@item V
451This modifier shows the version number of @code{ar}.
452@end table
453
454@node ar scripts
455@section Controlling @code{ar} with a script
456
457@smallexample
458ar -M [ <@var{script} ]
459@end smallexample
460
461@cindex MRI compatibility, @code{ar}
462@cindex scripts, @code{ar}
463If you use the single command-line option @samp{-M} with @code{ar}, you
464can control its operation with a rudimentary command language. This
465form of @code{ar} operates interactively if standard input is coming
466directly from a terminal. During interactive use, @code{ar} prompts for
467input (the prompt is @samp{AR >}), and continues executing even after
468errors. If you redirect standard input to a script file, no prompts are
469issued, and @code{ar} abandons execution (with a nonzero exit code)
470on any error.
471
472The @code{ar} command language is @emph{not} designed to be equivalent
473to the command-line options; in fact, it provides somewhat less control
474over archives. The only purpose of the command language is to ease the
475transition to @sc{gnu} @code{ar} for developers who already have scripts
476written for the MRI ``librarian'' program.
477
478The syntax for the @code{ar} command language is straightforward:
479@itemize @bullet
480@item
481commands are recognized in upper or lower case; for example, @code{LIST}
482is the same as @code{list}. In the following descriptions, commands are
483shown in upper case for clarity.
484
485@item
486a single command may appear on each line; it is the first word on the
487line.
488
489@item
490empty lines are allowed, and have no effect.
491
492@item
493comments are allowed; text after either of the characters @samp{*}
494or @samp{;} is ignored.
495
496@item
497Whenever you use a list of names as part of the argument to an @code{ar}
498command, you can separate the individual names with either commas or
499blanks. Commas are shown in the explanations below, for clarity.
500
501@item
502@samp{+} is used as a line continuation character; if @samp{+} appears
503at the end of a line, the text on the following line is considered part
504of the current command.
505@end itemize
506
507Here are the commands you can use in @code{ar} scripts, or when using
508@code{ar} interactively. Three of them have special significance:
509
510@code{OPEN} or @code{CREATE} specify a @dfn{current archive}, which is
511a temporary file required for most of the other commands.
512
513@code{SAVE} commits the changes so far specified by the script. Prior
514to @code{SAVE}, commands affect only the temporary copy of the current
515archive.
516
517@table @code
518@item ADDLIB @var{archive}
519@itemx ADDLIB @var{archive} (@var{module}, @var{module}, @dots{} @var{module})
520Add all the contents of @var{archive} (or, if specified, each named
521@var{module} from @var{archive}) to the current archive.
522
523Requires prior use of @code{OPEN} or @code{CREATE}.
524
525@item ADDMOD @var{member}, @var{member}, @dots{} @var{member}
526@c FIXME! w/Replacement?? If so, like "ar r @var{archive} @var{names}"
527@c else like "ar q..."
528Add each named @var{member} as a module in the current archive.
529
530Requires prior use of @code{OPEN} or @code{CREATE}.
531
532@item CLEAR
533Discard the contents of the current archive, canceling the effect of
534any operations since the last @code{SAVE}. May be executed (with no
535effect) even if no current archive is specified.
536
537@item CREATE @var{archive}
538Creates an archive, and makes it the current archive (required for many
539other commands). The new archive is created with a temporary name; it
540is not actually saved as @var{archive} until you use @code{SAVE}.
541You can overwrite existing archives; similarly, the contents of any
542existing file named @var{archive} will not be destroyed until @code{SAVE}.
543
544@item DELETE @var{module}, @var{module}, @dots{} @var{module}
545Delete each listed @var{module} from the current archive; equivalent to
546@samp{ar -d @var{archive} @var{module} @dots{} @var{module}}.
547
548Requires prior use of @code{OPEN} or @code{CREATE}.
549
550@item DIRECTORY @var{archive} (@var{module}, @dots{} @var{module})
551@itemx DIRECTORY @var{archive} (@var{module}, @dots{} @var{module}) @var{outputfile}
552List each named @var{module} present in @var{archive}. The separate
553command @code{VERBOSE} specifies the form of the output: when verbose
554output is off, output is like that of @samp{ar -t @var{archive}
555@var{module}@dots{}}. When verbose output is on, the listing is like
556@samp{ar -tv @var{archive} @var{module}@dots{}}.
557
558Output normally goes to the standard output stream; however, if you
559specify @var{outputfile} as a final argument, @code{ar} directs the
560output to that file.
561
562@item END
563Exit from @code{ar}, with a @code{0} exit code to indicate successful
564completion. This command does not save the output file; if you have
565changed the current archive since the last @code{SAVE} command, those
566changes are lost.
567
568@item EXTRACT @var{module}, @var{module}, @dots{} @var{module}
569Extract each named @var{module} from the current archive, writing them
570into the current directory as separate files. Equivalent to @samp{ar -x
571@var{archive} @var{module}@dots{}}.
572
573Requires prior use of @code{OPEN} or @code{CREATE}.
574
575@ignore
576@c FIXME Tokens but no commands???
577@item FULLDIR
578
579@item HELP
580@end ignore
581
582@item LIST
583Display full contents of the current archive, in ``verbose'' style
584regardless of the state of @code{VERBOSE}. The effect is like @samp{ar
c89746f6 585tv @var{archive}}. (This single command is a @sc{gnu} @code{ar}
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586enhancement, rather than present for MRI compatibility.)
587
588Requires prior use of @code{OPEN} or @code{CREATE}.
589
590@item OPEN @var{archive}
591Opens an existing archive for use as the current archive (required for
592many other commands). Any changes as the result of subsequent commands
593will not actually affect @var{archive} until you next use @code{SAVE}.
594
595@item REPLACE @var{module}, @var{module}, @dots{} @var{module}
596In the current archive, replace each existing @var{module} (named in
597the @code{REPLACE} arguments) from files in the current working directory.
598To execute this command without errors, both the file, and the module in
599the current archive, must exist.
600
601Requires prior use of @code{OPEN} or @code{CREATE}.
602
603@item VERBOSE
604Toggle an internal flag governing the output from @code{DIRECTORY}.
605When the flag is on, @code{DIRECTORY} output matches output from
606@samp{ar -tv }@dots{}.
607
608@item SAVE
609Commit your changes to the current archive, and actually save it as a
610file with the name specified in the last @code{CREATE} or @code{OPEN}
611command.
612
613Requires prior use of @code{OPEN} or @code{CREATE}.
614
615@end table
616
617@iftex
618@node ld
619@chapter ld
620@cindex linker
621@kindex ld
622The @sc{gnu} linker @code{ld} is now described in a separate manual.
623@xref{Top,, Overview,, Using LD: the @sc{gnu} linker}.
624@end iftex
625
626@node nm
627@chapter nm
628@cindex symbols
629@kindex nm
630
631@smallexample
632nm [ -a | --debug-syms ] [ -g | --extern-only ]
28c309a2 633 [ -B ] [ -C | --demangle[=@var{style}] ] [ -D | --dynamic ]
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634 [ -s | --print-armap ] [ -A | -o | --print-file-name ]
635 [ -n | -v | --numeric-sort ] [ -p | --no-sort ]
636 [ -r | --reverse-sort ] [ --size-sort ] [ -u | --undefined-only ]
637 [ -t @var{radix} | --radix=@var{radix} ] [ -P | --portability ]
638 [ --target=@var{bfdname} ] [ -f @var{format} | --format=@var{format} ]
639 [ --defined-only ] [-l | --line-numbers ]
640 [ --no-demangle ] [ -V | --version ] [ --help ] [ @var{objfile}@dots{} ]
641@end smallexample
642
643@sc{gnu} @code{nm} lists the symbols from object files @var{objfile}@dots{}.
f20a759a 644If no object files are listed as arguments, @code{nm} assumes the file
252b5132
RH
645@file{a.out}.
646
647For each symbol, @code{nm} shows:
648
649@itemize @bullet
650@item
651The symbol value, in the radix selected by options (see below), or
652hexadecimal by default.
653
654@item
655The symbol type. At least the following types are used; others are, as
656well, depending on the object file format. If lowercase, the symbol is
657local; if uppercase, the symbol is global (external).
658
659@c Some more detail on exactly what these symbol types are used for
660@c would be nice.
661@table @code
662@item A
663The symbol's value is absolute, and will not be changed by further
664linking.
665
666@item B
667The symbol is in the uninitialized data section (known as BSS).
668
669@item C
670The symbol is common. Common symbols are uninitialized data. When
671linking, multiple common symbols may appear with the same name. If the
672symbol is defined anywhere, the common symbols are treated as undefined
673references. For more details on common symbols, see the discussion of
674--warn-common in @ref{Options,,Linker options,ld.info,The GNU linker}.
675
676@item D
677The symbol is in the initialized data section.
678
679@item G
680The symbol is in an initialized data section for small objects. Some
681object file formats permit more efficient access to small data objects,
682such as a global int variable as opposed to a large global array.
683
684@item I
685The symbol is an indirect reference to another symbol. This is a GNU
686extension to the a.out object file format which is rarely used.
687
688@item N
689The symbol is a debugging symbol.
690
691@item R
692The symbol is in a read only data section.
693
694@item S
695The symbol is in an uninitialized data section for small objects.
696
697@item T
698The symbol is in the text (code) section.
699
700@item U
701The symbol is undefined.
702
fad6fcbb
NC
703@item V
704The symbol is a weak object. When a weak defined symbol is linked with
705a normal defined symbol, the normal defined symbol is used with no error.
706When a weak undefined symbol is linked and the symbol is not defined,
707the value of the weak symbol becomes zero with no error.
708
252b5132 709@item W
fad6fcbb
NC
710The symbol is a weak symbol that has not been specifically tagged as a
711weak object symbol. When a weak defined symbol is linked with a normal
712defined symbol, the normal defined symbol is used with no error.
713When a weak undefined symbol is linked and the symbol is not defined,
714the value of the weak symbol becomes zero with no error.
252b5132
RH
715
716@item -
717The symbol is a stabs symbol in an a.out object file. In this case, the
718next values printed are the stabs other field, the stabs desc field, and
719the stab type. Stabs symbols are used to hold debugging information;
720for more information, see @ref{Top,Stabs,Stabs Overview,stabs.info, The
721``stabs'' debug format}.
722
723@item ?
724The symbol type is unknown, or object file format specific.
725@end table
726
727@item
728The symbol name.
729@end itemize
730
731The long and short forms of options, shown here as alternatives, are
732equivalent.
733
734@table @code
735@item -A
736@itemx -o
737@itemx --print-file-name
738@cindex input file name
739@cindex file name
740@cindex source file name
f20a759a 741Precede each symbol by the name of the input file (or archive member)
252b5132
RH
742in which it was found, rather than identifying the input file once only,
743before all of its symbols.
744
745@item -a
746@itemx --debug-syms
747@cindex debugging symbols
748Display all symbols, even debugger-only symbols; normally these are not
749listed.
750
751@item -B
752@cindex @code{nm} format
753@cindex @code{nm} compatibility
754The same as @samp{--format=bsd} (for compatibility with the MIPS @code{nm}).
755
756@item -C
28c309a2 757@itemx --demangle[=@var{style}]
252b5132
RH
758@cindex demangling in nm
759Decode (@dfn{demangle}) low-level symbol names into user-level names.
760Besides removing any initial underscore prepended by the system, this
28c309a2
NC
761makes C++ function names readable. Different compilers have different
762mangling styles. The optional demangling style argument can be used to
763choose an appropriate demangling style for your compiler. @xref{c++filt},
764for more information on demangling.
252b5132
RH
765
766@item --no-demangle
767Do not demangle low-level symbol names. This is the default.
768
769@item -D
770@itemx --dynamic
771@cindex dynamic symbols
772Display the dynamic symbols rather than the normal symbols. This is
773only meaningful for dynamic objects, such as certain types of shared
774libraries.
775
776@item -f @var{format}
777@itemx --format=@var{format}
778@cindex @code{nm} format
779@cindex @code{nm} compatibility
780Use the output format @var{format}, which can be @code{bsd},
781@code{sysv}, or @code{posix}. The default is @code{bsd}.
782Only the first character of @var{format} is significant; it can be
783either upper or lower case.
784
785@item -g
786@itemx --extern-only
787@cindex external symbols
788Display only external symbols.
789
790@item -l
791@itemx --line-numbers
792@cindex symbol line numbers
793For each symbol, use debugging information to try to find a filename and
794line number. For a defined symbol, look for the line number of the
795address of the symbol. For an undefined symbol, look for the line
796number of a relocation entry which refers to the symbol. If line number
797information can be found, print it after the other symbol information.
798
799@item -n
800@itemx -v
801@itemx --numeric-sort
802Sort symbols numerically by their addresses, rather than alphabetically
803by their names.
804
805@item -p
806@itemx --no-sort
807@cindex sorting symbols
808Do not bother to sort the symbols in any order; print them in the order
809encountered.
810
811@item -P
812@itemx --portability
813Use the POSIX.2 standard output format instead of the default format.
814Equivalent to @samp{-f posix}.
815
816@item -s
817@itemx --print-armap
818@cindex symbol index, listing
819When listing symbols from archive members, include the index: a mapping
820(stored in the archive by @code{ar} or @code{ranlib}) of which modules
821contain definitions for which names.
822
823@item -r
824@itemx --reverse-sort
825Reverse the order of the sort (whether numeric or alphabetic); let the
826last come first.
827
828@item --size-sort
829Sort symbols by size. The size is computed as the difference between
830the value of the symbol and the value of the symbol with the next higher
831value. The size of the symbol is printed, rather than the value.
832
833@item -t @var{radix}
834@itemx --radix=@var{radix}
835Use @var{radix} as the radix for printing the symbol values. It must be
836@samp{d} for decimal, @samp{o} for octal, or @samp{x} for hexadecimal.
837
838@item --target=@var{bfdname}
839@cindex object code format
840Specify an object code format other than your system's default format.
841@xref{Target Selection}, for more information.
842
843@item -u
844@itemx --undefined-only
845@cindex external symbols
846@cindex undefined symbols
847Display only undefined symbols (those external to each object file).
848
849@item --defined-only
850@cindex external symbols
851@cindex undefined symbols
852Display only defined symbols for each object file.
853
854@item -V
855@itemx --version
856Show the version number of @code{nm} and exit.
857
858@item --help
859Show a summary of the options to @code{nm} and exit.
860@end table
861
862@node objcopy
863@chapter objcopy
864
865@smallexample
866objcopy [ -F @var{bfdname} | --target=@var{bfdname} ]
867 [ -I @var{bfdname} | --input-target=@var{bfdname} ]
868 [ -O @var{bfdname} | --output-target=@var{bfdname} ]
869 [ -S | --strip-all ] [ -g | --strip-debug ]
870 [ -K @var{symbolname} | --keep-symbol=@var{symbolname} ]
871 [ -N @var{symbolname} | --strip-symbol=@var{symbolname} ]
872 [ -L @var{symbolname} | --localize-symbol=@var{symbolname} ]
873 [ -W @var{symbolname} | --weaken-symbol=@var{symbolname} ]
874 [ -x | --discard-all ] [ -X | --discard-locals ]
875 [ -b @var{byte} | --byte=@var{byte} ]
876 [ -i @var{interleave} | --interleave=@var{interleave} ]
f91ea849 877 [ -j @var{sectionname} | --only-section=@var{sectionname} ]
252b5132
RH
878 [ -R @var{sectionname} | --remove-section=@var{sectionname} ]
879 [ -p | --preserve-dates ] [ --debugging ]
880 [ --gap-fill=@var{val} ] [ --pad-to=@var{address} ]
881 [ --set-start=@var{val} ] [ --adjust-start=@var{incr} ]
882 [ --change-addresses=@var{incr} ]
57938635
AM
883 [ --change-section-address @var{section}@{=,+,-@}@var{val} ]
884 [ --change-section-lma @var{section}@{=,+,-@}@var{val} ]
885 [ --change-section-vma @var{section}@{=,+,-@}@var{val} ]
252b5132 886 [ --change-warnings ] [ --no-change-warnings ]
57938635
AM
887 [ --set-section-flags @var{section}=@var{flags} ]
888 [ --add-section @var{sectionname}=@var{filename} ]
252b5132 889 [ --change-leading-char ] [ --remove-leading-char ]
57938635 890 [ --redefine-sym @var{old}=@var{new} ] [ --weaken ]
252b5132
RH
891 [ -v | --verbose ] [ -V | --version ] [ --help ]
892 @var{infile} [@var{outfile}]
893@end smallexample
894
895The @sc{gnu} @code{objcopy} utility copies the contents of an object
896file to another. @code{objcopy} uses the @sc{gnu} @sc{bfd} Library to
897read and write the object files. It can write the destination object
898file in a format different from that of the source object file. The
899exact behavior of @code{objcopy} is controlled by command-line options.
ccd13d18
L
900Note that @code{objcopy} should be able to copy a fully linked file
901between any two formats. However, copying a relocatable object file
902between any two formats may not work as expected.
252b5132
RH
903
904@code{objcopy} creates temporary files to do its translations and
905deletes them afterward. @code{objcopy} uses @sc{bfd} to do all its
906translation work; it has access to all the formats described in @sc{bfd}
907and thus is able to recognize most formats without being told
908explicitly. @xref{BFD,,BFD,ld.info,Using LD}.
909
910@code{objcopy} can be used to generate S-records by using an output
911target of @samp{srec} (e.g., use @samp{-O srec}).
912
913@code{objcopy} can be used to generate a raw binary file by using an
914output target of @samp{binary} (e.g., use @samp{-O binary}). When
915@code{objcopy} generates a raw binary file, it will essentially produce
916a memory dump of the contents of the input object file. All symbols and
917relocation information will be discarded. The memory dump will start at
918the load address of the lowest section copied into the output file.
919
920When generating an S-record or a raw binary file, it may be helpful to
921use @samp{-S} to remove sections containing debugging information. In
922some cases @samp{-R} will be useful to remove sections which contain
f20a759a 923information that is not needed by the binary file.
252b5132
RH
924
925@table @code
926@item @var{infile}
927@itemx @var{outfile}
f20a759a 928The input and output files, respectively.
252b5132
RH
929If you do not specify @var{outfile}, @code{objcopy} creates a
930temporary file and destructively renames the result with
931the name of @var{infile}.
932
933@item -I @var{bfdname}
934@itemx --input-target=@var{bfdname}
935Consider the source file's object format to be @var{bfdname}, rather than
936attempting to deduce it. @xref{Target Selection}, for more information.
937
938@item -O @var{bfdname}
939@itemx --output-target=@var{bfdname}
940Write the output file using the object format @var{bfdname}.
941@xref{Target Selection}, for more information.
942
943@item -F @var{bfdname}
944@itemx --target=@var{bfdname}
945Use @var{bfdname} as the object format for both the input and the output
946file; i.e., simply transfer data from source to destination with no
947translation. @xref{Target Selection}, for more information.
948
f91ea849
ILT
949@item -j @var{sectionname}
950@itemx --only-section=@var{sectionname}
951Copy only the named section from the input file to the output file.
952This option may be given more than once. Note that using this option
953inappropriately may make the output file unusable.
954
252b5132
RH
955@item -R @var{sectionname}
956@itemx --remove-section=@var{sectionname}
957Remove any section named @var{sectionname} from the output file. This
958option may be given more than once. Note that using this option
959inappropriately may make the output file unusable.
960
961@item -S
962@itemx --strip-all
963Do not copy relocation and symbol information from the source file.
964
965@item -g
966@itemx --strip-debug
967Do not copy debugging symbols from the source file.
968
969@item --strip-unneeded
970Strip all symbols that are not needed for relocation processing.
971
972@item -K @var{symbolname}
973@itemx --keep-symbol=@var{symbolname}
974Copy only symbol @var{symbolname} from the source file. This option may
975be given more than once.
976
977@item -N @var{symbolname}
978@itemx --strip-symbol=@var{symbolname}
979Do not copy symbol @var{symbolname} from the source file. This option
980may be given more than once.
981
982@item -L @var{symbolname}
983@itemx --localize-symbol=@var{symbolname}
984Make symbol @var{symbolname} local to the file, so that it is not
985visible externally. This option may be given more than once.
986
987@item -W @var{symbolname}
988@itemx --weaken-symbol=@var{symbolname}
989Make symbol @var{symbolname} weak. This option may be given more than once.
990
991@item -x
992@itemx --discard-all
993Do not copy non-global symbols from the source file.
994@c FIXME any reason to prefer "non-global" to "local" here?
995
996@item -X
997@itemx --discard-locals
998Do not copy compiler-generated local symbols.
999(These usually start with @samp{L} or @samp{.}.)
1000
1001@item -b @var{byte}
1002@itemx --byte=@var{byte}
1003Keep only every @var{byte}th byte of the input file (header data is not
1004affected). @var{byte} can be in the range from 0 to @var{interleave}-1,
1005where @var{interleave} is given by the @samp{-i} or @samp{--interleave}
1006option, or the default of 4. This option is useful for creating files
1007to program @sc{rom}. It is typically used with an @code{srec} output
1008target.
1009
1010@item -i @var{interleave}
1011@itemx --interleave=@var{interleave}
1012Only copy one out of every @var{interleave} bytes. Select which byte to
1013copy with the @var{-b} or @samp{--byte} option. The default is 4.
1014@code{objcopy} ignores this option if you do not specify either @samp{-b} or
1015@samp{--byte}.
1016
1017@item -p
1018@itemx --preserve-dates
1019Set the access and modification dates of the output file to be the same
1020as those of the input file.
1021
1022@item --debugging
1023Convert debugging information, if possible. This is not the default
1024because only certain debugging formats are supported, and the
1025conversion process can be time consuming.
1026
1027@item --gap-fill @var{val}
1028Fill gaps between sections with @var{val}. This operation applies to
1029the @emph{load address} (LMA) of the sections. It is done by increasing
1030the size of the section with the lower address, and filling in the extra
1031space created with @var{val}.
1032
1033@item --pad-to @var{address}
1034Pad the output file up to the load address @var{address}. This is
1035done by increasing the size of the last section. The extra space is
1036filled in with the value specified by @samp{--gap-fill} (default zero).
1037
1038@item --set-start @var{val}
f20a759a 1039Set the start address of the new file to @var{val}. Not all object file
252b5132
RH
1040formats support setting the start address.
1041
1042@item --change-start @var{incr}
1043@itemx --adjust-start @var{incr}
1044@cindex changing start address
1045Change the start address by adding @var{incr}. Not all object file
1046formats support setting the start address.
1047
1048@item --change-addresses @var{incr}
1049@itemx --adjust-vma @var{incr}
1050@cindex changing object addresses
1051Change the VMA and LMA addresses of all sections, as well as the start
1052address, by adding @var{incr}. Some object file formats do not permit
1053section addresses to be changed arbitrarily. Note that this does not
1054relocate the sections; if the program expects sections to be loaded at a
1055certain address, and this option is used to change the sections such
1056that they are loaded at a different address, the program may fail.
1057
1058@item --change-section-address @var{section}@{=,+,-@}@var{val}
1059@itemx --adjust-section-vma @var{section}@{=,+,-@}@var{val}
1060@cindex changing section address
1061Set or change both the VMA address and the LMA address of the named
1062@var{section}. If @samp{=} is used, the section address is set to
1063@var{val}. Otherwise, @var{val} is added to or subtracted from the
1064section address. See the comments under @samp{--change-addresses},
1065above. If @var{section} does not exist in the input file, a warning will
1066be issued, unless @samp{--no-change-warnings} is used.
1067
1068@item --change-section-lma @var{section}@{=,+,-@}@var{val}
1069@cindex changing section LMA
1070Set or change the LMA address of the named @var{section}. The LMA
1071address is the address where the section will be loaded into memory at
1072program load time. Normally this is the same as the VMA address, which
1073is the address of the section at program run time, but on some systems,
1074especially those where a program is held in ROM, the two can be
1075different. If @samp{=} is used, the section address is set to
1076@var{val}. Otherwise, @var{val} is added to or subtracted from the
1077section address. See the comments under @samp{--change-addresses},
1078above. If @var{section} does not exist in the input file, a warning
1079will be issued, unless @samp{--no-change-warnings} is used.
1080
1081@item --change-section-vma @var{section}@{=,+,-@}@var{val}
1082@cindex changing section VMA
1083Set or change the VMA address of the named @var{section}. The VMA
1084address is the address where the section will be located once the
1085program has started executing. Normally this is the same as the LMA
1086address, which is the address where the section will be loaded into
1087memory, but on some systems, especially those where a program is held in
1088ROM, the two can be different. If @samp{=} is used, the section address
1089is set to @var{val}. Otherwise, @var{val} is added to or subtracted
1090from the section address. See the comments under
1091@samp{--change-addresses}, above. If @var{section} does not exist in
1092the input file, a warning will be issued, unless
1093@samp{--no-change-warnings} is used.
1094
1095@item --change-warnings
1096@itemx --adjust-warnings
1097If @samp{--change-section-address} or @samp{--change-section-lma} or
1098@samp{--change-section-vma} is used, and the named section does not
1099exist, issue a warning. This is the default.
1100
1101@item --no-change-warnings
1102@itemx --no-adjust-warnings
1103Do not issue a warning if @samp{--change-section-address} or
1104@samp{--adjust-section-lma} or @samp{--adjust-section-vma} is used, even
1105if the named section does not exist.
1106
1107@item --set-section-flags @var{section}=@var{flags}
1108Set the flags for the named section. The @var{flags} argument is a
1109comma separated string of flag names. The recognized names are
3994e2c6
ILT
1110@samp{alloc}, @samp{contents}, @samp{load}, @samp{noload},
1111@samp{readonly}, @samp{code}, @samp{data}, @samp{rom}, @samp{share}, and
1112@samp{debug}. You can set the @samp{contents} flag for a section which
1113does not have contents, but it is not meaningful to clear the
1114@samp{contents} flag of a section which does have contents--just remove
1115the section instead. Not all flags are meaningful for all object file
1116formats.
252b5132
RH
1117
1118@item --add-section @var{sectionname}=@var{filename}
1119Add a new section named @var{sectionname} while copying the file. The
1120contents of the new section are taken from the file @var{filename}. The
1121size of the section will be the size of the file. This option only
1122works on file formats which can support sections with arbitrary names.
1123
1124@item --change-leading-char
1125Some object file formats use special characters at the start of
1126symbols. The most common such character is underscore, which compilers
1127often add before every symbol. This option tells @code{objcopy} to
1128change the leading character of every symbol when it converts between
1129object file formats. If the object file formats use the same leading
1130character, this option has no effect. Otherwise, it will add a
1131character, or remove a character, or change a character, as
1132appropriate.
1133
1134@item --remove-leading-char
1135If the first character of a global symbol is a special symbol leading
1136character used by the object file format, remove the character. The
1137most common symbol leading character is underscore. This option will
1138remove a leading underscore from all global symbols. This can be useful
1139if you want to link together objects of different file formats with
1140different conventions for symbol names. This is different from
1141@code{--change-leading-char} because it always changes the symbol name
1142when appropriate, regardless of the object file format of the output
1143file.
1144
57938635
AM
1145@item --redefine-sym @var{old}=@var{new}
1146Change the name of a symbol @var{old}, to @var{new}. This can be useful
1147when one is trying link two things together for which you have no
1148source, and there are name collisions.
1149
252b5132
RH
1150@item --weaken
1151Change all global symbols in the file to be weak. This can be useful
1152when building an object which will be linked against other objects using
1153the @code{-R} option to the linker. This option is only effective when
1154using an object file format which supports weak symbols.
1155
1156@item -V
1157@itemx --version
1158Show the version number of @code{objcopy}.
1159
1160@item -v
1161@itemx --verbose
1162Verbose output: list all object files modified. In the case of
1163archives, @samp{objcopy -V} lists all members of the archive.
1164
1165@item --help
1166Show a summary of the options to @code{objcopy}.
1167@end table
1168
1169@node objdump
1170@chapter objdump
1171
1172@cindex object file information
1173@kindex objdump
1174
1175@smallexample
1176objdump [ -a | --archive-headers ]
1dada9c5 1177 [ -b @var{bfdname} | --target=@var{bfdname} ]
28c309a2 1178 [ -C | --demangle[=@var{style}] ]
1dada9c5
NC
1179 [ -d | --disassemble ]
1180 [ -D | --disassemble-all ]
1181 [ -z | --disassemble-zeroes ]
252b5132
RH
1182 [ -EB | -EL | --endian=@{big | little @} ]
1183 [ -f | --file-headers ]
f1563258 1184 [ --file-start-context ]
1dada9c5
NC
1185 [ -g | --debugging ]
1186 [ -h | --section-headers | --headers ]
1187 [ -i | --info ]
252b5132 1188 [ -j @var{section} | --section=@var{section} ]
1dada9c5
NC
1189 [ -l | --line-numbers ]
1190 [ -S | --source ]
252b5132 1191 [ -m @var{machine} | --architecture=@var{machine} ]
dd92f639 1192 [ -M @var{options} | --disassembler-options=@var{options}]
252b5132 1193 [ -p | --private-headers ]
1dada9c5
NC
1194 [ -r | --reloc ]
1195 [ -R | --dynamic-reloc ]
1196 [ -s | --full-contents ]
1197 [ -G | --stabs ]
1198 [ -t | --syms ]
1199 [ -T | --dynamic-syms ]
1200 [ -x | --all-headers ]
1201 [ -w | --wide ]
1202 [ --start-address=@var{address} ]
252b5132 1203 [ --stop-address=@var{address} ]
1dada9c5
NC
1204 [ --prefix-addresses]
1205 [ --[no-]show-raw-insn ]
252b5132 1206 [ --adjust-vma=@var{offset} ]
1dada9c5
NC
1207 [ -V | --version ]
1208 [ -H | --help ]
252b5132
RH
1209 @var{objfile}@dots{}
1210@end smallexample
1211
1212@code{objdump} displays information about one or more object files.
1213The options control what particular information to display. This
1214information is mostly useful to programmers who are working on the
1215compilation tools, as opposed to programmers who just want their
1216program to compile and work.
1217
1218@var{objfile}@dots{} are the object files to be examined. When you
1219specify archives, @code{objdump} shows information on each of the member
1220object files.
1221
1222The long and short forms of options, shown here as alternatives, are
1dada9c5
NC
1223equivalent. At least one option from the list
1224@samp{-a,-d,-D,-f,-g,-G,-h,-H,-p,-r,-R,-S,-t,-T,-V,-x} must be given.
252b5132
RH
1225
1226@table @code
1227@item -a
1228@itemx --archive-header
1229@cindex archive headers
1230If any of the @var{objfile} files are archives, display the archive
1231header information (in a format similar to @samp{ls -l}). Besides the
1232information you could list with @samp{ar tv}, @samp{objdump -a} shows
1233the object file format of each archive member.
1234
1235@item --adjust-vma=@var{offset}
1236@cindex section addresses in objdump
1237@cindex VMA in objdump
1238When dumping information, first add @var{offset} to all the section
1239addresses. This is useful if the section addresses do not correspond to
1240the symbol table, which can happen when putting sections at particular
1241addresses when using a format which can not represent section addresses,
1242such as a.out.
1243
1244@item -b @var{bfdname}
1245@itemx --target=@var{bfdname}
1246@cindex object code format
1247Specify that the object-code format for the object files is
1248@var{bfdname}. This option may not be necessary; @var{objdump} can
1249automatically recognize many formats.
1250
1251For example,
1252@example
1253objdump -b oasys -m vax -h fu.o
1254@end example
1255@noindent
1256displays summary information from the section headers (@samp{-h}) of
1257@file{fu.o}, which is explicitly identified (@samp{-m}) as a VAX object
1258file in the format produced by Oasys compilers. You can list the
1259formats available with the @samp{-i} option.
1260@xref{Target Selection}, for more information.
1261
1262@item -C
28c309a2 1263@itemx --demangle[=@var{style}]
252b5132
RH
1264@cindex demangling in objdump
1265Decode (@dfn{demangle}) low-level symbol names into user-level names.
1266Besides removing any initial underscore prepended by the system, this
28c309a2
NC
1267makes C++ function names readable. Different compilers have different
1268mangling styles. The optional demangling style argument can be used to
1269choose an appropriate demangling style for your compiler. @xref{c++filt},
1270for more information on demangling.
252b5132 1271
1dada9c5 1272@item -G
252b5132
RH
1273@item --debugging
1274Display debugging information. This attempts to parse debugging
1275information stored in the file and print it out using a C like syntax.
1276Only certain types of debugging information have been implemented.
1277
1278@item -d
1279@itemx --disassemble
1280@cindex disassembling object code
1281@cindex machine instructions
1282Display the assembler mnemonics for the machine instructions from
1283@var{objfile}. This option only disassembles those sections which are
1284expected to contain instructions.
1285
1286@item -D
1287@itemx --disassemble-all
1288Like @samp{-d}, but disassemble the contents of all sections, not just
1289those expected to contain instructions.
1290
1291@item --prefix-addresses
1292When disassembling, print the complete address on each line. This is
1293the older disassembly format.
1294
1295@item --disassemble-zeroes
1296Normally the disassembly output will skip blocks of zeroes. This
1297option directs the disassembler to disassemble those blocks, just like
1298any other data.
1299
1300@item -EB
1301@itemx -EL
1302@itemx --endian=@{big|little@}
1303@cindex endianness
1304@cindex disassembly endianness
1305Specify the endianness of the object files. This only affects
1306disassembly. This can be useful when disassembling a file format which
1307does not describe endianness information, such as S-records.
1308
1309@item -f
1310@itemx --file-header
1311@cindex object file header
1312Display summary information from the overall header of
1313each of the @var{objfile} files.
1314
f1563258
TW
1315@item --file-start-context
1316@cindex source code context
1317Specify that when displaying interlisted source code/disassembly
1318(assumes '-S') from a file that has not yet been displayed, extend the
1319context to the start of the file.
1320
252b5132
RH
1321@item -h
1322@itemx --section-header
1323@itemx --header
1324@cindex section headers
1325Display summary information from the section headers of the
1326object file.
1327
1328File segments may be relocated to nonstandard addresses, for example by
1329using the @samp{-Ttext}, @samp{-Tdata}, or @samp{-Tbss} options to
1330@code{ld}. However, some object file formats, such as a.out, do not
1331store the starting address of the file segments. In those situations,
1332although @code{ld} relocates the sections correctly, using @samp{objdump
1333-h} to list the file section headers cannot show the correct addresses.
1334Instead, it shows the usual addresses, which are implicit for the
1335target.
1336
1337@item --help
1338Print a summary of the options to @code{objdump} and exit.
1339
1340@item -i
1341@itemx --info
1342@cindex architectures available
1343@cindex object formats available
1344Display a list showing all architectures and object formats available
1345for specification with @samp{-b} or @samp{-m}.
1346
1347@item -j @var{name}
1348@itemx --section=@var{name}
1349@cindex section information
1350Display information only for section @var{name}.
1351
1352@item -l
1353@itemx --line-numbers
1354@cindex source filenames for object files
1355Label the display (using debugging information) with the filename and
1356source line numbers corresponding to the object code or relocs shown.
1357Only useful with @samp{-d}, @samp{-D}, or @samp{-r}.
1358
1359@item -m @var{machine}
1360@itemx --architecture=@var{machine}
1361@cindex architecture
1362@cindex disassembly architecture
1363Specify the architecture to use when disassembling object files. This
1364can be useful when disassembling object files which do not describe
1365architecture information, such as S-records. You can list the available
1366architectures with the @samp{-i} option.
1367
dd92f639
NC
1368@item -M @var{options}
1369@itemx --disassembler-options=@var{options}
1370Pass target specific information to the disassembler. Only supported on
1371some targets.
1372
1373If the target is an ARM architecture then this switch can be used to
1374select which register name set is used during disassembler. Specifying
58efb6c0
NC
1375@samp{-M reg-name-std} (the default) will select the register names as
1376used in ARM's instruction set documentation, but with register 13 called
1377'sp', register 14 called 'lr' and register 15 called 'pc'. Specifying
1378@samp{-M reg-names-apcs} will select the name set used by the ARM
1379Procedure Call Standard, whilst specifying @samp{-M reg-names-raw} will
1380just use @samp{r} followed by the register number.
1381
1382There are also two variants on the APCS register naming scheme enabled
0fff8110 1383by @samp{-M reg-names-atpcs} and @samp{-M reg-names-special-atpcs} which
58efb6c0
NC
1384use the ARM/Thumb Procedure Call Standard naming conventions. (Eiuther
1385with the normal register name sor the special register names).
dd92f639 1386
8f915f68
NC
1387This option can also be used for ARM architectures to force the
1388disassembler to interpret all instructions as THUMB instructions by
1389using the switch @samp{--disassembler-options=force-thumb}. This can be
1390useful when attempting to disassemble thumb code produced by other
1391compilers.
1392
252b5132
RH
1393@item -p
1394@itemx --private-headers
1395Print information that is specific to the object file format. The exact
1396information printed depends upon the object file format. For some
1397object file formats, no additional information is printed.
1398
1399@item -r
1400@itemx --reloc
1401@cindex relocation entries, in object file
1402Print the relocation entries of the file. If used with @samp{-d} or
1403@samp{-D}, the relocations are printed interspersed with the
1404disassembly.
1405
1406@item -R
1407@itemx --dynamic-reloc
1408@cindex dynamic relocation entries, in object file
1409Print the dynamic relocation entries of the file. This is only
1410meaningful for dynamic objects, such as certain types of shared
1411libraries.
1412
1413@item -s
1414@itemx --full-contents
1415@cindex sections, full contents
1416@cindex object file sections
1417Display the full contents of any sections requested.
1418
1419@item -S
1420@itemx --source
1421@cindex source disassembly
1422@cindex disassembly, with source
1423Display source code intermixed with disassembly, if possible. Implies
1424@samp{-d}.
1425
1426@item --show-raw-insn
1427When disassembling instructions, print the instruction in hex as well as
1428in symbolic form. This is the default except when
1429@code{--prefix-addresses} is used.
1430
1431@item --no-show-raw-insn
1432When disassembling instructions, do not print the instruction bytes.
1433This is the default when @code{--prefix-addresses} is used.
1434
1dada9c5 1435@item -G
252b5132
RH
1436@item --stabs
1437@cindex stab
1438@cindex .stab
1439@cindex debug symbols
1440@cindex ELF object file format
1441Display the full contents of any sections requested. Display the
1442contents of the .stab and .stab.index and .stab.excl sections from an
1443ELF file. This is only useful on systems (such as Solaris 2.0) in which
1444@code{.stab} debugging symbol-table entries are carried in an ELF
1445section. In most other file formats, debugging symbol-table entries are
1446interleaved with linkage symbols, and are visible in the @samp{--syms}
1447output. For more information on stabs symbols, see @ref{Top,Stabs,Stabs
1448Overview,stabs.info, The ``stabs'' debug format}.
1449
1450@item --start-address=@var{address}
1451@cindex start-address
1452Start displaying data at the specified address. This affects the output
1453of the @code{-d}, @code{-r} and @code{-s} options.
1454
1455@item --stop-address=@var{address}
1456@cindex stop-address
1457Stop displaying data at the specified address. This affects the output
1458of the @code{-d}, @code{-r} and @code{-s} options.
1459
1460@item -t
1461@itemx --syms
1462@cindex symbol table entries, printing
1463Print the symbol table entries of the file.
1464This is similar to the information provided by the @samp{nm} program.
1465
1466@item -T
1467@itemx --dynamic-syms
1468@cindex dynamic symbol table entries, printing
1469Print the dynamic symbol table entries of the file. This is only
1470meaningful for dynamic objects, such as certain types of shared
1471libraries. This is similar to the information provided by the @samp{nm}
1472program when given the @samp{-D} (@samp{--dynamic}) option.
1473
1474@item --version
1475Print the version number of @code{objdump} and exit.
1476
1477@item -x
1478@itemx --all-header
1479@cindex all header information, object file
1480@cindex header information, all
1481Display all available header information, including the symbol table and
1482relocation entries. Using @samp{-x} is equivalent to specifying all of
1483@samp{-a -f -h -r -t}.
1484
1485@item -w
1486@itemx --wide
1487@cindex wide output, printing
1488Format some lines for output devices that have more than 80 columns.
1489@end table
1490
1491@node ranlib
1492@chapter ranlib
1493
1494@kindex ranlib
1495@cindex archive contents
1496@cindex symbol index
1497
1498@smallexample
1499ranlib [-vV] @var{archive}
1500@end smallexample
1501
1502@code{ranlib} generates an index to the contents of an archive and
1503stores it in the archive. The index lists each symbol defined by a
1504member of an archive that is a relocatable object file.
1505
1506You may use @samp{nm -s} or @samp{nm --print-armap} to list this index.
1507
1508An archive with such an index speeds up linking to the library and
1509allows routines in the library to call each other without regard to
1510their placement in the archive.
1511
1512The @sc{gnu} @code{ranlib} program is another form of @sc{gnu} @code{ar}; running
1513@code{ranlib} is completely equivalent to executing @samp{ar -s}.
1514@xref{ar}.
1515
1516@table @code
1517@item -v
1518@itemx -V
f20a759a 1519@itemx --version
252b5132
RH
1520Show the version number of @code{ranlib}.
1521@end table
1522
1523@node size
1524@chapter size
1525
1526@kindex size
1527@cindex section sizes
1528
1529@smallexample
1530size [ -A | -B | --format=@var{compatibility} ]
1531 [ --help ] [ -d | -o | -x | --radix=@var{number} ]
1532 [ --target=@var{bfdname} ] [ -V | --version ]
1533 [ @var{objfile}@dots{} ]
1534@end smallexample
1535
1536The @sc{gnu} @code{size} utility lists the section sizes---and the total
1537size---for each of the object or archive files @var{objfile} in its
1538argument list. By default, one line of output is generated for each
1539object file or each module in an archive.
1540
1541@var{objfile}@dots{} are the object files to be examined.
1542If none are specified, the file @code{a.out} will be used.
1543
1544The command line options have the following meanings:
1545
1546@table @code
1547@item -A
1548@itemx -B
1549@itemx --format=@var{compatibility}
1550@cindex @code{size} display format
1551Using one of these options, you can choose whether the output from @sc{gnu}
1552@code{size} resembles output from System V @code{size} (using @samp{-A},
1553or @samp{--format=sysv}), or Berkeley @code{size} (using @samp{-B}, or
1554@samp{--format=berkeley}). The default is the one-line format similar to
1555Berkeley's.
1556@c Bonus for doc-source readers: you can also say --format=strange (or
1557@c anything else that starts with 's') for sysv, and --format=boring (or
1558@c anything else that starts with 'b') for Berkeley.
1559
1560Here is an example of the Berkeley (default) format of output from
1561@code{size}:
1562@smallexample
f20a759a 1563$ size --format=Berkeley ranlib size
252b5132
RH
1564text data bss dec hex filename
1565294880 81920 11592 388392 5ed28 ranlib
1566294880 81920 11888 388688 5ee50 size
1567@end smallexample
1568
1569@noindent
1570This is the same data, but displayed closer to System V conventions:
1571
1572@smallexample
f20a759a 1573$ size --format=SysV ranlib size
252b5132
RH
1574ranlib :
1575section size addr
1576.text 294880 8192
1577.data 81920 303104
1578.bss 11592 385024
1579Total 388392
1580
1581
1582size :
1583section size addr
1584.text 294880 8192
1585.data 81920 303104
1586.bss 11888 385024
1587Total 388688
1588@end smallexample
1589
1590@item --help
1591Show a summary of acceptable arguments and options.
1592
1593@item -d
1594@itemx -o
1595@itemx -x
1596@itemx --radix=@var{number}
1597@cindex @code{size} number format
1598@cindex radix for section sizes
1599Using one of these options, you can control whether the size of each
1600section is given in decimal (@samp{-d}, or @samp{--radix=10}); octal
1601(@samp{-o}, or @samp{--radix=8}); or hexadecimal (@samp{-x}, or
1602@samp{--radix=16}). In @samp{--radix=@var{number}}, only the three
1603values (8, 10, 16) are supported. The total size is always given in two
1604radices; decimal and hexadecimal for @samp{-d} or @samp{-x} output, or
1605octal and hexadecimal if you're using @samp{-o}.
1606
1607@item --target=@var{bfdname}
1608@cindex object code format
1609Specify that the object-code format for @var{objfile} is
1610@var{bfdname}. This option may not be necessary; @code{size} can
1611automatically recognize many formats.
1612@xref{Target Selection}, for more information.
1613
1614@item -V
1615@itemx --version
1616Display the version number of @code{size}.
1617@end table
1618
1619@node strings
1620@chapter strings
1621@kindex strings
1622@cindex listings strings
1623@cindex printing strings
1624@cindex strings, printing
1625
1626@smallexample
1627strings [-afov] [-@var{min-len}] [-n @var{min-len}] [-t @var{radix}] [-]
1628 [--all] [--print-file-name] [--bytes=@var{min-len}]
1629 [--radix=@var{radix}] [--target=@var{bfdname}]
1630 [--help] [--version] @var{file}@dots{}
1631@end smallexample
1632
1633For each @var{file} given, @sc{gnu} @code{strings} prints the printable
1634character sequences that are at least 4 characters long (or the number
1635given with the options below) and are followed by an unprintable
1636character. By default, it only prints the strings from the initialized
1637and loaded sections of object files; for other types of files, it prints
1638the strings from the whole file.
1639
1640@code{strings} is mainly useful for determining the contents of non-text
1641files.
1642
1643@table @code
1644@item -a
1645@itemx --all
1646@itemx -
1647Do not scan only the initialized and loaded sections of object files;
1648scan the whole files.
1649
1650@item -f
1651@itemx --print-file-name
1652Print the name of the file before each string.
1653
1654@item --help
1655Print a summary of the program usage on the standard output and exit.
1656
1657@item -@var{min-len}
1658@itemx -n @var{min-len}
1659@itemx --bytes=@var{min-len}
1660Print sequences of characters that are at least @var{min-len} characters
1661long, instead of the default 4.
1662
1663@item -o
1664Like @samp{-t o}. Some other versions of @code{strings} have @samp{-o}
1665act like @samp{-t d} instead. Since we can not be compatible with both
1666ways, we simply chose one.
1667
1668@item -t @var{radix}
1669@itemx --radix=@var{radix}
1670Print the offset within the file before each string. The single
1671character argument specifies the radix of the offset---@samp{o} for
1672octal, @samp{x} for hexadecimal, or @samp{d} for decimal.
1673
1674@item --target=@var{bfdname}
1675@cindex object code format
1676Specify an object code format other than your system's default format.
1677@xref{Target Selection}, for more information.
1678
1679@item -v
1680@itemx --version
1681Print the program version number on the standard output and exit.
1682@end table
1683
1684@node strip
1685@chapter strip
1686
1687@kindex strip
1688@cindex removing symbols
1689@cindex discarding symbols
1690@cindex symbols, discarding
1691
1692@smallexample
1693strip [ -F @var{bfdname} | --target=@var{bfdname} ]
1694 [ -I @var{bfdname} | --input-target=@var{bfdname} ]
1695 [ -O @var{bfdname} | --output-target=@var{bfdname} ]
1696 [ -s | --strip-all ] [ -S | -g | --strip-debug ]
1697 [ -K @var{symbolname} | --keep-symbol=@var{symbolname} ]
1698 [ -N @var{symbolname} | --strip-symbol=@var{symbolname} ]
1699 [ -x | --discard-all ] [ -X | --discard-locals ]
1700 [ -R @var{sectionname} | --remove-section=@var{sectionname} ]
1701 [ -o @var{file} ] [ -p | --preserve-dates ]
1702 [ -v | --verbose ] [ -V | --version ] [ --help ]
1703 @var{objfile}@dots{}
1704@end smallexample
1705
1706@sc{gnu} @code{strip} discards all symbols from object files
1707@var{objfile}. The list of object files may include archives.
1708At least one object file must be given.
1709
1710@code{strip} modifies the files named in its argument,
1711rather than writing modified copies under different names.
1712
1713@table @code
1714@item -F @var{bfdname}
1715@itemx --target=@var{bfdname}
1716Treat the original @var{objfile} as a file with the object
1717code format @var{bfdname}, and rewrite it in the same format.
1718@xref{Target Selection}, for more information.
1719
1720@item --help
1721Show a summary of the options to @code{strip} and exit.
1722
1723@item -I @var{bfdname}
1724@itemx --input-target=@var{bfdname}
1725Treat the original @var{objfile} as a file with the object
1726code format @var{bfdname}.
1727@xref{Target Selection}, for more information.
1728
1729@item -O @var{bfdname}
1730@itemx --output-target=@var{bfdname}
1731Replace @var{objfile} with a file in the output format @var{bfdname}.
1732@xref{Target Selection}, for more information.
1733
1734@item -R @var{sectionname}
1735@itemx --remove-section=@var{sectionname}
1736Remove any section named @var{sectionname} from the output file. This
1737option may be given more than once. Note that using this option
1738inappropriately may make the output file unusable.
1739
1740@item -s
1741@itemx --strip-all
1742Remove all symbols.
1743
1744@item -g
1745@itemx -S
1746@itemx --strip-debug
1747Remove debugging symbols only.
1748
1749@item --strip-unneeded
1750Remove all symbols that are not needed for relocation processing.
1751
1752@item -K @var{symbolname}
1753@itemx --keep-symbol=@var{symbolname}
1754Keep only symbol @var{symbolname} from the source file. This option may
1755be given more than once.
1756
1757@item -N @var{symbolname}
1758@itemx --strip-symbol=@var{symbolname}
1759Remove symbol @var{symbolname} from the source file. This option may be
1760given more than once, and may be combined with strip options other than
1761@code{-K}.
1762
1763@item -o @var{file}
1764Put the stripped output in @var{file}, rather than replacing the
1765existing file. When this argument is used, only one @var{objfile}
1766argument may be specified.
1767
1768@item -p
1769@itemx --preserve-dates
1770Preserve the access and modification dates of the file.
1771
1772@item -x
1773@itemx --discard-all
1774Remove non-global symbols.
1775
1776@item -X
1777@itemx --discard-locals
1778Remove compiler-generated local symbols.
1779(These usually start with @samp{L} or @samp{.}.)
1780
1781@item -V
1782@itemx --version
1783Show the version number for @code{strip}.
1784
1785@item -v
1786@itemx --verbose
1787Verbose output: list all object files modified. In the case of
1788archives, @samp{strip -v} lists all members of the archive.
1789@end table
1790
9d51cc66 1791@node c++filt, addr2line, strip, Top
252b5132
RH
1792@chapter c++filt
1793
1794@kindex c++filt
1795@cindex demangling C++ symbols
1796
1797@smallexample
1798c++filt [ -_ | --strip-underscores ]
1799 [ -j | --java ]
1800 [ -n | --no-strip-underscores ]
1801 [ -s @var{format} | --format=@var{format} ]
1802 [ --help ] [ --version ] [ @var{symbol}@dots{} ]
1803@end smallexample
1804
9d51cc66 1805@kindex cxxfilt
252b5132
RH
1806The C++ and Java languages provides function overloading, which means
1807that you can write many functions with the same name (providing each
1808takes parameters of different types). All C++ and Java function names
1809are encoded into a low-level assembly label (this process is known as
9d51cc66
ILT
1810@dfn{mangling}). The @code{c++filt}
1811@footnote{MS-DOS does not allow @kbd{+} characters in file names, so on
1812MS-DOS this program is named @code{cxxfilt}.}
1813program does the inverse mapping: it decodes (@dfn{demangles}) low-level
1814names into user-level names so that the linker can keep these overloaded
1815functions from clashing.
252b5132
RH
1816
1817Every alphanumeric word (consisting of letters, digits, underscores,
1818dollars, or periods) seen in the input is a potential label. If the
1819label decodes into a C++ name, the C++ name replaces the low-level
1820name in the output.
1821
1822You can use @code{c++filt} to decipher individual symbols:
1823
1824@example
1825c++filt @var{symbol}
1826@end example
1827
1828If no @var{symbol} arguments are given, @code{c++filt} reads symbol
1829names from the standard input and writes the demangled names to the
1830standard output. All results are printed on the standard output.
1831
1832@table @code
1833@item -_
1834@itemx --strip-underscores
1835On some systems, both the C and C++ compilers put an underscore in front
1836of every name. For example, the C name @code{foo} gets the low-level
1837name @code{_foo}. This option removes the initial underscore. Whether
1838@code{c++filt} removes the underscore by default is target dependent.
1839
1840@item -j
1841@itemx --java
1842Prints demangled names using Java syntax. The default is to use C++
1843syntax.
1844
1845@item -n
1846@itemx --no-strip-underscores
1847Do not remove the initial underscore.
1848
1849@item -s @var{format}
1850@itemx --format=@var{format}
1851@sc{gnu} @code{nm} can decode three different methods of mangling, used by
1852different C++ compilers. The argument to this option selects which
1853method it uses:
1854
1855@table @code
1856@item gnu
1857the one used by the @sc{gnu} compiler (the default method)
1858@item lucid
1859the one used by the Lucid compiler
1860@item arm
1861the one specified by the C++ Annotated Reference Manual
1862@item hp
1863the one used by the HP compiler
1864@item edg
1865the one used by the EDG compiler
28c309a2
NC
1866@item gnu-new-abi
1867the one used by the @sc{gnu} compiler with the new ABI.
252b5132
RH
1868@end table
1869
1870@item --help
1871Print a summary of the options to @code{c++filt} and exit.
1872
1873@item --version
1874Print the version number of @code{c++filt} and exit.
1875@end table
1876
1877@quotation
1878@emph{Warning:} @code{c++filt} is a new utility, and the details of its
1879user interface are subject to change in future releases. In particular,
1880a command-line option may be required in the the future to decode a name
1881passed as an argument on the command line; in other words,
1882
1883@example
1884c++filt @var{symbol}
1885@end example
1886
1887@noindent
1888may in a future release become
1889
1890@example
1891c++filt @var{option} @var{symbol}
1892@end example
1893@end quotation
1894
1895@node addr2line
1896@chapter addr2line
1897
1898@kindex addr2line
1899@cindex address to file name and line number
1900
1901@smallexample
1902addr2line [ -b @var{bfdname} | --target=@var{bfdname} ]
28c309a2 1903 [ -C | --demangle[=@var{style} ]
252b5132
RH
1904 [ -e @var{filename} | --exe=@var{filename} ]
1905 [ -f | --functions ] [ -s | --basename ]
1906 [ -H | --help ] [ -V | --version ]
1907 [ addr addr ... ]
1908@end smallexample
1909
1910@code{addr2line} translates program addresses into file names and line
1911numbers. Given an address and an executable, it uses the debugging
1912information in the executable to figure out which file name and line
1913number are associated with a given address.
1914
1915The executable to use is specified with the @code{-e} option. The
f20a759a 1916default is the file @file{a.out}.
252b5132
RH
1917
1918@code{addr2line} has two modes of operation.
1919
1920In the first, hexadecimal addresses are specified on the command line,
1921and @code{addr2line} displays the file name and line number for each
1922address.
1923
1924In the second, @code{addr2line} reads hexadecimal addresses from
1925standard input, and prints the file name and line number for each
1926address on standard output. In this mode, @code{addr2line} may be used
1927in a pipe to convert dynamically chosen addresses.
1928
1929The format of the output is @samp{FILENAME:LINENO}. The file name and
1930line number for each address is printed on a separate line. If the
1931@code{-f} option is used, then each @samp{FILENAME:LINENO} line is
1932preceded by a @samp{FUNCTIONNAME} line which is the name of the function
1933containing the address.
1934
1935If the file name or function name can not be determined,
1936@code{addr2line} will print two question marks in their place. If the
1937line number can not be determined, @code{addr2line} will print 0.
1938
1939The long and short forms of options, shown here as alternatives, are
1940equivalent.
1941
1942@table @code
1943@item -b @var{bfdname}
1944@itemx --target=@var{bfdname}
1945@cindex object code format
1946Specify that the object-code format for the object files is
1947@var{bfdname}.
1948
1949@item -C
28c309a2 1950@itemx --demangle[=@var{style}]
252b5132
RH
1951@cindex demangling in objdump
1952Decode (@dfn{demangle}) low-level symbol names into user-level names.
1953Besides removing any initial underscore prepended by the system, this
28c309a2
NC
1954makes C++ function names readable. Different compilers have different
1955mangling styles. The optional demangling style argument can be used to
1956choose an appropriate demangling style for your compiler. @xref{c++filt},
1957for more information on demangling.
252b5132
RH
1958
1959@item -e @var{filename}
1960@itemx --exe=@var{filename}
1961Specify the name of the executable for which addresses should be
1962translated. The default file is @file{a.out}.
1963
1964@item -f
1965@itemx --functions
1966Display function names as well as file and line number information.
1967
1968@item -s
1969@itemx --basenames
1970Display only the base of each file name.
e107c42f 1971@end table
252b5132
RH
1972
1973@node nlmconv
1974@chapter nlmconv
1975
1976@code{nlmconv} converts a relocatable object file into a NetWare
1977Loadable Module.
1978
1979@ignore
1980@code{nlmconv} currently works with @samp{i386} object
1981files in @code{coff}, @sc{elf}, or @code{a.out} format, and @sc{SPARC}
1982object files in @sc{elf}, or @code{a.out} format@footnote{
1983@code{nlmconv} should work with any @samp{i386} or @sc{sparc} object
1984format in the Binary File Descriptor library. It has only been tested
1985with the above formats.}.
1986@end ignore
1987
1988@quotation
1989@emph{Warning:} @code{nlmconv} is not always built as part of the binary
1990utilities, since it is only useful for NLM targets.
1991@end quotation
1992
1993@smallexample
1994nlmconv [ -I @var{bfdname} | --input-target=@var{bfdname} ]
1995 [ -O @var{bfdname} | --output-target=@var{bfdname} ]
1996 [ -T @var{headerfile} | --header-file=@var{headerfile} ]
1997 [ -d | --debug] [ -l @var{linker} | --linker=@var{linker} ]
1998 [ -h | --help ] [ -V | --version ]
1999 @var{infile} @var{outfile}
2000@end smallexample
2001
2002@code{nlmconv} converts the relocatable @samp{i386} object file
2003@var{infile} into the NetWare Loadable Module @var{outfile}, optionally
2004reading @var{headerfile} for NLM header information. For instructions
2005on writing the NLM command file language used in header files, see the
2006@samp{linkers} section, @samp{NLMLINK} in particular, of the @cite{NLM
2007Development and Tools Overview}, which is part of the NLM Software
2008Developer's Kit (``NLM SDK''), available from Novell, Inc.
2009@code{nlmconv} uses the @sc{gnu} Binary File Descriptor library to read
2010@var{infile}; see @ref{BFD,,BFD,ld.info,Using LD}, for
2011more information.
2012
2013@code{nlmconv} can perform a link step. In other words, you can list
2014more than one object file for input if you list them in the definitions
2015file (rather than simply specifying one input file on the command line).
2016In this case, @code{nlmconv} calls the linker for you.
2017
2018@table @code
2019@item -I @var{bfdname}
2020@itemx --input-target=@var{bfdname}
2021Object format of the input file. @code{nlmconv} can usually determine
2022the format of a given file (so no default is necessary).
2023@xref{Target Selection}, for more information.
2024
2025@item -O @var{bfdname}
2026@itemx --output-target=@var{bfdname}
2027Object format of the output file. @code{nlmconv} infers the output
2028format based on the input format, e.g. for a @samp{i386} input file the
2029output format is @samp{nlm32-i386}.
2030@xref{Target Selection}, for more information.
2031
2032@item -T @var{headerfile}
2033@itemx --header-file=@var{headerfile}
2034Reads @var{headerfile} for NLM header information. For instructions on
2035writing the NLM command file language used in header files, see@ see the
2036@samp{linkers} section, of the @cite{NLM Development and Tools
2037Overview}, which is part of the NLM Software Developer's Kit, available
2038from Novell, Inc.
2039
2040@item -d
2041@itemx --debug
2042Displays (on standard error) the linker command line used by @code{nlmconv}.
2043
2044@item -l @var{linker}
2045@itemx --linker=@var{linker}
2046Use @var{linker} for any linking. @var{linker} can be an absolute or a
2047relative pathname.
2048
2049@item -h
2050@itemx --help
2051Prints a usage summary.
2052
2053@item -V
2054@itemx --version
2055Prints the version number for @code{nlmconv}.
2056@end table
2057
2058@node windres
2059@chapter windres
2060
2061@code{windres} may be used to manipulate Windows resources.
2062
2063@quotation
2064@emph{Warning:} @code{windres} is not always built as part of the binary
2065utilities, since it is only useful for Windows targets.
2066@end quotation
2067
2068@smallexample
2069windres [options] [input-file] [output-file]
2070@end smallexample
2071
2072@code{windres} reads resources from an input file and copies them into
2073an output file. Either file may be in one of three formats:
2074
2075@table @code
2076@item rc
2077A text format read by the Resource Compiler.
2078
2079@item res
2080A binary format generated by the Resource Compiler.
2081
2082@item coff
2083A COFF object or executable.
2084@end table
2085
2086The exact description of these different formats is available in
2087documentation from Microsoft.
2088
2089When @code{windres} converts from the @code{rc} format to the @code{res}
2090format, it is acting like the Windows Resource Compiler. When
2091@code{windres} converts from the @code{res} format to the @code{coff}
2092format, it is acting like the Windows @code{CVTRES} program.
2093
2094When @code{windres} generates an @code{rc} file, the output is similar
2095but not identical to the format expected for the input. When an input
2096@code{rc} file refers to an external filename, an output @code{rc} file
2097will instead include the file contents.
2098
2099If the input or output format is not specified, @code{windres} will
2100guess based on the file name, or, for the input file, the file contents.
2101A file with an extension of @file{.rc} will be treated as an @code{rc}
2102file, a file with an extension of @file{.res} will be treated as a
2103@code{res} file, and a file with an extension of @file{.o} or
2104@file{.exe} will be treated as a @code{coff} file.
2105
2106If no output file is specified, @code{windres} will print the resources
2107in @code{rc} format to standard output.
2108
2109The normal use is for you to write an @code{rc} file, use @code{windres}
2110to convert it to a COFF object file, and then link the COFF file into
2111your application. This will make the resources described in the
2112@code{rc} file available to Windows.
2113
2114@table @code
2115@item -i @var{filename}
2116@itemx --input @var{filename}
2117The name of the input file. If this option is not used, then
2118@code{windres} will use the first non-option argument as the input file
2119name. If there are no non-option arguments, then @code{windres} will
2120read from standard input. @code{windres} can not read a COFF file from
2121standard input.
2122
2123@item -o @var{filename}
2124@itemx --output @var{filename}
2125The name of the output file. If this option is not used, then
2126@code{windres} will use the first non-option argument, after any used
2127for the input file name, as the output file name. If there is no
2128non-option argument, then @code{windres} will write to standard output.
2129@code{windres} can not write a COFF file to standard output.
2130
2131@item -I @var{format}
2132@itemx --input-format @var{format}
2133The input format to read. @var{format} may be @samp{res}, @samp{rc}, or
2134@samp{coff}. If no input format is specified, @code{windres} will
2135guess, as described above.
2136
2137@item -O @var{format}
2138@itemx --output-format @var{format}
2139The output format to generate. @var{format} may be @samp{res},
2140@samp{rc}, or @samp{coff}. If no output format is specified,
2141@code{windres} will guess, as described above.
2142
2143@item -F @var{target}
2144@itemx --target @var{target}
2145Specify the BFD format to use for a COFF file as input or output. This
2146is a BFD target name; you can use the @code{--help} option to see a list
2147of supported targets. Normally @code{windres} will use the default
2148format, which is the first one listed by the @code{--help} option.
2149@ref{Target Selection}.
2150
2151@item --preprocessor @var{program}
2152When @code{windres} reads an @code{rc} file, it runs it through the C
2153preprocessor first. This option may be used to specify the preprocessor
2154to use, including any leading arguments. The default preprocessor
2155argument is @code{gcc -E -xc-header -DRC_INVOKED}.
2156
2157@item --include-dir @var{directory}
2158Specify an include directory to use when reading an @code{rc} file.
2159@code{windres} will pass this to the preprocessor as an @code{-I}
2160option. @code{windres} will also search this directory when looking for
2161files named in the @code{rc} file.
2162
751d21b5 2163@item -D @var{target}
ad0481cd 2164@itemx --define @var{sym}[=@var{val}]
252b5132
RH
2165Specify a @code{-D} option to pass to the preprocessor when reading an
2166@code{rc} file.
2167
751d21b5
DD
2168@item -v
2169Enable verbose mode. This tells you what the preprocessor is if you
2170didn't specify one.
2171
252b5132
RH
2172@item --language @var{val}
2173Specify the default language to use when reading an @code{rc} file.
2174@var{val} should be a hexadecimal language code. The low eight bits are
2175the language, and the high eight bits are the sublanguage.
2176
5a298d2d
NC
2177@item --use-temp-file
2178Use a temporary file to instead of using popen to read the output of
2179the preprocessor. Use this option if the popen implementation is buggy
2180on the host (eg., certain non-English language versions of Windows 95 and
2181Windows 98 are known to have buggy popen where the output will instead
2182go the console).
2183
2184@item --no-use-temp-file
2185Use popen, not a temporary file, to read the output of the preprocessor.
2186This is the default behaviour.
2187
252b5132
RH
2188@item --help
2189Prints a usage summary.
2190
2191@item --version
2192Prints the version number for @code{windres}.
2193
2194@item --yydebug
2195If @code{windres} is compiled with @code{YYDEBUG} defined as @code{1},
2196this will turn on parser debugging.
2197@end table
2198
2199
2200@node dlltool
2201@chapter Create files needed to build and use DLLs
2202@cindex DLL
2203@kindex dlltool
2204
2205@code{dlltool} may be used to create the files needed to build and use
2206dynamic link libraries (DLLs).
2207
2208@quotation
2209@emph{Warning:} @code{dlltool} is not always built as part of the binary
2210utilities, since it is only useful for those targets which support DLLs.
2211@end quotation
2212
2213@smallexample
2214dlltool [-d|--input-def @var{def-file-name}]
2215 [-b|--base-file @var{base-file-name}]
2216 [-e|--output-exp @var{exports-file-name}]
2217 [-z|--output-def @var{def-file-name}]
2218 [-l|--output-lib @var{library-file-name}]
2219 [--export-all-symbols] [--no-export-all-symbols]
2220 [--exclude-symbols @var{list}]
2221 [--no-default-excludes]
2222 [-S|--as @var{path-to-assembler}] [-f|--as-flags @var{options}]
2223 [-D|--dllname @var{name}] [-m|--machine @var{machine}]
2224 [-a|--add-indirect] [-U|--add-underscore] [-k|--kill-at]
2225 [-A|--add-stdcall-alias]
2226 [-x|--no-idata4] [-c|--no-idata5] [-i|--interwork]
2227 [-n|--nodelete] [-v|--verbose] [-h|--help] [-V|--version]
2228 [object-file @dots{}]
2229@end smallexample
2230
2231@code{dlltool} reads its inputs, which can come from the @samp{-d} and
2232@samp{-b} options as well as object files specified on the command
2233line. It then processes these inputs and if the @samp{-e} option has
2234been specified it creates a exports file. If the @samp{-l} option
2235has been specified it creates a library file and if the @samp{-z} option
2236has been specified it creates a def file. Any or all of the -e, -l
2237and -z options can be present in one invocation of dlltool.
2238
2239When creating a DLL, along with the source for the DLL, it is necessary
2240to have three other files. @code{dlltool} can help with the creation of
2241these files.
2242
2243The first file is a @samp{.def} file which specifies which functions are
2244exported from the DLL, which functions the DLL imports, and so on. This
2245is a text file and can be created by hand, or @code{dlltool} can be used
2246to create it using the @samp{-z} option. In this case @code{dlltool}
2247will scan the object files specified on its command line looking for
2248those functions which have been specially marked as being exported and
2249put entries for them in the .def file it creates.
2250
2251In order to mark a function as being exported from a DLL, it needs to
2252have an @samp{-export:<name_of_function>} entry in the @samp{.drectve}
2253section of the object file. This can be done in C by using the
2254asm() operator:
2255
2256@smallexample
2257 asm (".section .drectve");
2258 asm (".ascii \"-export:my_func\"");
2259
2260 int my_func (void) @{ @dots{} @}
2261@end smallexample
2262
2263The second file needed for DLL creation is an exports file. This file
2264is linked with the object files that make up the body of the DLL and it
2265handles the interface between the DLL and the outside world. This is a
2266binary file and it can be created by giving the @samp{-e} option to
2267@code{dlltool} when it is creating or reading in a .def file.
2268
2269The third file needed for DLL creation is the library file that programs
2270will link with in order to access the functions in the DLL. This file
2271can be created by giving the @samp{-l} option to dlltool when it
2272is creating or reading in a .def file.
2273
2274@code{dlltool} builds the library file by hand, but it builds the
2275exports file by creating temporary files containing assembler statements
2276and then assembling these. The @samp{-S} command line option can be
2277used to specify the path to the assembler that dlltool will use,
2278and the @samp{-f} option can be used to pass specific flags to that
2279assembler. The @samp{-n} can be used to prevent dlltool from deleting
2280these temporary assembler files when it is done, and if @samp{-n} is
2281specified twice then this will prevent dlltool from deleting the
2282temporary object files it used to build the library.
2283
2284Here is an example of creating a DLL from a source file @samp{dll.c} and
2285also creating a program (from an object file called @samp{program.o})
2286that uses that DLL:
2287
2288@smallexample
2289 gcc -c dll.c
2290 dlltool -e exports.o -l dll.lib dll.o
2291 gcc dll.o exports.o -o dll.dll
2292 gcc program.o dll.lib -o program
2293@end smallexample
2294
2295The command line options have the following meanings:
2296
2297@table @code
2298
2299@item -d @var{filename}
2300@itemx --input-def @var{filename}
2301@cindex input .def file
2302Specifies the name of a .def file to be read in and processed.
2303
2304@item -b @var{filename}
2305@itemx --base-file @var{filename}
2306@cindex base files
2307Specifies the name of a base file to be read in and processed. The
2308contents of this file will be added to the relocation section in the
2309exports file generated by dlltool.
2310
2311@item -e @var{filename}
2312@itemx --output-exp @var{filename}
2313Specifies the name of the export file to be created by dlltool.
2314
2315@item -z @var{filename}
2316@itemx --output-def @var{filename}
2317Specifies the name of the .def file to be created by dlltool.
2318
2319@item -l @var{filename}
2320@itemx --output-lib @var{filename}
2321Specifies the name of the library file to be created by dlltool.
2322
2323@item --export-all-symbols
2324Treat all global and weak defined symbols found in the input object
2325files as symbols to be exported. There is a small list of symbols which
2326are not exported by default; see the @code{--no-default-excludes}
2327option. You may add to the list of symbols to not export by using the
2328@code{--exclude-symbols} option.
2329
2330@item --no-export-all-symbols
2331Only export symbols explicitly listed in an input .def file or in
2332@samp{.drectve} sections in the input object files. This is the default
2333behaviour. The @samp{.drectve} sections are created by @samp{dllexport}
2334attributes in the source code.
2335
2336@item --exclude-symbols @var{list}
2337Do not export the symbols in @var{list}. This is a list of symbol names
2338separated by comma or colon characters. The symbol names should not
2339contain a leading underscore. This is only meaningful when
2340@code{--export-all-symbols} is used.
2341
2342@item --no-default-excludes
2343When @code{--export-all-symbols} is used, it will by default avoid
2344exporting certain special symbols. The current list of symbols to avoid
2345exporting is @samp{DllMain@@12}, @samp{DllEntryPoint@@0},
2346@samp{impure_ptr}. You may use the @code{--no-default-excludes} option
2347to go ahead and export these special symbols. This is only meaningful
2348when @code{--export-all-symbols} is used.
2349
2350@item -S @var{path}
2351@itemx --as @var{path}
2352Specifies the path, including the filename, of the assembler to be used
2353to create the exports file.
2354
2355@item -f @var{switches}
2356@itemx --as-flags @var{switches}
2357Specifies any specific command line switches to be passed to the
2358assembler when building the exports file. This option will work even if
2359the @samp{-S} option is not used. This option only takes one argument,
2360and if it occurs more than once on the command line, then later
2361occurrences will override earlier occurrences. So if it is necessary to
2362pass multiple switches to the assembler they should be enclosed in
2363double quotes.
2364
2365@item -D @var{name}
2366@itemx --dll-name @var{name}
2367Specifies the name to be stored in the .def file as the name of the DLL
2368when the @samp{-e} option is used. If this option is not present, then
2369the filename given to the @samp{-e} option will be used as the name of
2370the DLL.
2371
2372@item -m @var{machine}
2373@itemx -machine @var{machine}
2374Specifies the type of machine for which the library file should be
2375built. @code{dlltool} has a built in default type, depending upon how
2376it was created, but this option can be used to override that. This is
2377normally only useful when creating DLLs for an ARM processor, when the
2378contents of the DLL are actually encode using THUMB instructions.
2379
2380@item -a
2381@itemx --add-indirect
2382Specifies that when @code{dlltool} is creating the exports file it
2383should add a section which allows the exported functions to be
2384referenced without using the import library. Whatever the hell that
2385means!
2386
2387@item -U
2388@itemx --add-underscore
2389Specifies that when @code{dlltool} is creating the exports file it
2390should prepend an underscore to the names of the exported functions.
2391
2392@item -k
2393@itemx --kill-at
2394Specifies that when @code{dlltool} is creating the exports file it
2395should not append the string @samp{@@ <number>}. These numbers are
2396called ordinal numbers and they represent another way of accessing the
2397function in a DLL, other than by name.
2398
2399@item -A
2400@itemx --add-stdcall-alias
2401Specifies that when @code{dlltool} is creating the exports file it
2402should add aliases for stdcall symbols without @samp{@@ <number>}
2403in addition to the symbols with @samp{@@ <number>}.
2404
2405@item -x
2406@itemx --no-idata4
2407Specifies that when @code{dlltool} is creating the exports and library
2408files it should omit the .idata4 section. This is for compatibility
2409with certain operating systems.
2410
2411@item -c
2412@itemx --no-idata5
2413Specifies that when @code{dlltool} is creating the exports and library
2414files it should omit the .idata5 section. This is for compatibility
2415with certain operating systems.
2416
2417@item -i
2418@itemx --interwork
2419Specifies that @code{dlltool} should mark the objects in the library
2420file and exports file that it produces as supporting interworking
2421between ARM and THUMB code.
2422
2423@item -n
2424@itemx --nodelete
2425Makes @code{dlltool} preserve the temporary assembler files it used to
2426create the exports file. If this option is repeated then dlltool will
2427also preserve the temporary object files it uses to create the library
2428file.
2429
2430@item -v
2431@itemx --verbose
2432Make dlltool describe what it is doing.
2433
2434@item -h
2435@itemx --help
2436Displays a list of command line options and then exits.
2437
2438@item -V
2439@itemx --version
2440Displays dlltool's version number and then exits.
2441
2442@end table
2443
2444@node readelf
2445@chapter readelf
2446
2447@cindex ELF file information
2448@kindex readelf
2449
2450@smallexample
2451readelf [ -a | --all ]
2452 [ -h | --file-header]
2453 [ -l | --program-headers | --segments]
2454 [ -S | --section-headers | --sections]
2455 [ -e | --headers]
2456 [ -s | --syms | --symbols]
779fe533 2457 [ -n | --notes]
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2458 [ -r | --relocs]
2459 [ -d | --dynamic]
2460 [ -V | --version-info]
2461 [ -D | --use-dynamic]
2462 [ -x <number> | --hex-dump=<number>]
2463 [ -w[liapr] | --debug-dump[=info,=line,=abbrev,=pubnames,=ranges]]
2464 [ --histogram]
2465 [ -v | --version]
2466 [ -H | --help]
2467 @var{elffile}@dots{}
2468@end smallexample
2469
2470@code{readelf} displays information about one or more ELF format object
2471files. The options control what particular information to display.
2472
2473@var{elffile}@dots{} are the object files to be examined. At the
2474moment, @code{readelf} does not support examining archives, nor does it
2475support examing 64 bit ELF files.
2476
2477The long and short forms of options, shown here as alternatives, are
2478equivalent. At least one option besides @samp{-v} or @samp{-H} must be
2479given.
2480
2481@table @code
2482@item -a
2483@itemx --all
2484Equivalent to specifiying @samp{--file-header},
2485@samp{--program-headers}, @samp{--sections}, @samp{--symbols},
779fe533
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2486@samp{--relocs}, @samp{--dynamic}, @samp{--notes} and
2487@samp{--version-info}.
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2488
2489@item -h
2490@itemx --file-header
2491@cindex ELF file header information
2492Displays the information contained in the ELF header at the start of the
2493file.
2494
2495@item -l
2496@itemx --program-headers
2497@itemx --segments
2498@cindex ELF program header information
2499@cindex ELF segment information
2500Displays the information contained in the file's segment headers, if it
2501has any.
2502
2503@item -S
2504@itemx --sections
2505@itemx --section-headers
2506@cindex ELF section information
2507Displays the information contained in the file's section headers, if it
2508has any.
2509
2510@item -s
2511@itemx --symbols
2512@itemx --syms
2513@cindex ELF symbol table information
2514Displays the entries in symbol table section of the file, if it has one.
2515
2516@item -e
2517@itemx --headers
2518Display all the headers in the file. Equivalent to @samp{-h -l -S}.
2519
779fe533
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2520@item -n
2521@itemx --notes
2522@cindex ELF core notes
2523Displays the contents of the NOTE segment, if it exists.
2524
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2525@item -r
2526@itemx --relocs
2527@cindex ELF reloc information
2528Displays the contents of the file's relocation section, if it ha one.
2529
2530@item -d
2531@itemx --dynamic
2532@cindex ELF dynamic section information
2533Displays the contents of the file's dynamic section, if it has one.
2534
2535@item -V
2536@itemx --version-info
2537@cindex ELF version sections informations
2538Displays the contents of the version sections in the file, it they
2539exist.
2540
2541@item -D
2542@itemx --use-dynamic
2543When displaying symbols, this option makes @code{readelf} use the
6dbb55b6 2544symbol table in the file's dynamic section, rather than the one in the
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2545symbols section.
2546
2547@item -x <number>
2548@itemx --hex-dump=<number>
2549Displays the contents of the indicated section as a hexadecimal dump.
2550
2551@item -w[liapr]
2552@itemx --debug-dump[=line,=info,=abbrev,=pubnames,=ranges]
2553Displays the contents of the debug sections in the file, if any are
2554present. If one of the optional letters or words follows the switch
2555then only data found in those specific sections will be dumped.
2556
2557@item --histogram
2558Display a histogram of bucket list lengths when displaying the contents
2559of the symbol tables.
2560
2561@item -v
2562@itemx --version
2563Display the version number of readelf.
2564
2565@item -H
2566@itemx --help
2567Display the command line options understood by @code{readelf}.
2568
2569@end table
2570
2571
2572@node Selecting The Target System
2573@chapter Selecting the target system
2574
2575You can specify three aspects of the target system to the @sc{gnu}
2576binary file utilities, each in several ways:
2577
2578@itemize @bullet
2579@item
2580the target
2581
2582@item
2583the architecture
2584
2585@item
2586the linker emulation (which applies to the linker only)
2587@end itemize
2588
2589In the following summaries, the lists of ways to specify values are in
2590order of decreasing precedence. The ways listed first override those
2591listed later.
2592
2593The commands to list valid values only list the values for which the
2594programs you are running were configured. If they were configured with
2595@samp{--enable-targets=all}, the commands list most of the available
2596values, but a few are left out; not all targets can be configured in at
2597once because some of them can only be configured @dfn{native} (on hosts
2598with the same type as the target system).
2599
2600@menu
2601* Target Selection::
2602* Architecture Selection::
2603* Linker Emulation Selection::
2604@end menu
2605
2606@node Target Selection
2607@section Target Selection
2608
2609A @dfn{target} is an object file format. A given target may be
2610supported for multiple architectures (@pxref{Architecture Selection}).
2611A target selection may also have variations for different operating
2612systems or architectures.
2613
2614The command to list valid target values is @samp{objdump -i}
2615(the first column of output contains the relevant information).
2616
2617Some sample values are: @samp{a.out-hp300bsd}, @samp{ecoff-littlemips},
2618@samp{a.out-sunos-big}.
2619
2620You can also specify a target using a configuration triplet. This is
f20a759a
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2621the same sort of name that is passed to @file{configure} to specify a
2622target. When you use a configuration triplet as an argument, it must be
2623fully canonicalized. You can see the canonical version of a triplet by
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2624running the shell script @file{config.sub} which is included with the
2625sources.
2626
2627Some sample configuration triplets are: @samp{m68k-hp-bsd},
2628@samp{mips-dec-ultrix}, @samp{sparc-sun-sunos}.
2629
2630@subheading @code{objdump} Target
2631
2632Ways to specify:
2633
2634@enumerate
2635@item
2636command line option: @samp{-b} or @samp{--target}
2637
2638@item
2639environment variable @code{GNUTARGET}
2640
2641@item
2642deduced from the input file
2643@end enumerate
2644
2645@subheading @code{objcopy} and @code{strip} Input Target
2646
2647Ways to specify:
2648
2649@enumerate
2650@item
2651command line options: @samp{-I} or @samp{--input-target}, or @samp{-F} or @samp{--target}
2652
2653@item
2654environment variable @code{GNUTARGET}
2655
2656@item
2657deduced from the input file
2658@end enumerate
2659
2660@subheading @code{objcopy} and @code{strip} Output Target
2661
2662Ways to specify:
2663
2664@enumerate
2665@item
2666command line options: @samp{-O} or @samp{--output-target}, or @samp{-F} or @samp{--target}
2667
2668@item
2669the input target (see ``@code{objcopy} and @code{strip} Input Target'' above)
2670
2671@item
2672environment variable @code{GNUTARGET}
2673
2674@item
2675deduced from the input file
2676@end enumerate
2677
2678@subheading @code{nm}, @code{size}, and @code{strings} Target
2679
2680Ways to specify:
2681
2682@enumerate
2683@item
2684command line option: @samp{--target}
2685
2686@item
2687environment variable @code{GNUTARGET}
2688
2689@item
2690deduced from the input file
2691@end enumerate
2692
2693@subheading Linker Input Target
2694
2695Ways to specify:
2696
2697@enumerate
2698@item
2699command line option: @samp{-b} or @samp{--format}
2700(@pxref{Options,,Options,ld.info,Using LD})
2701
2702@item
2703script command @code{TARGET}
2704(@pxref{Option Commands,,Option Commands,ld.info,Using LD})
2705
2706@item
2707environment variable @code{GNUTARGET}
2708(@pxref{Environment,,Environment,ld.info,Using LD})
2709
2710@item
2711the default target of the selected linker emulation
2712(@pxref{Linker Emulation Selection})
2713@end enumerate
2714
2715@subheading Linker Output Target
2716
2717Ways to specify:
2718
2719@enumerate
2720@item
2721command line option: @samp{-oformat}
2722(@pxref{Options,,Options,ld.info,Using LD})
2723
2724@item
2725script command @code{OUTPUT_FORMAT}
2726(@pxref{Option Commands,,Option Commands,ld.info,Using LD})
2727
2728@item
2729the linker input target (see ``Linker Input Target'' above)
2730@end enumerate
2731
2732@node Architecture Selection
2733@section Architecture selection
2734
2735An @dfn{architecture} is a type of @sc{cpu} on which an object file is
2736to run. Its name may contain a colon, separating the name of the
2737processor family from the name of the particular @sc{cpu}.
2738
2739The command to list valid architecture values is @samp{objdump -i} (the
2740second column contains the relevant information).
2741
2742Sample values: @samp{m68k:68020}, @samp{mips:3000}, @samp{sparc}.
2743
2744@subheading @code{objdump} Architecture
2745
2746Ways to specify:
2747
2748@enumerate
2749@item
2750command line option: @samp{-m} or @samp{--architecture}
2751
2752@item
2753deduced from the input file
2754@end enumerate
2755
2756@subheading @code{objcopy}, @code{nm}, @code{size}, @code{strings} Architecture
2757
2758Ways to specify:
2759
2760@enumerate
2761@item
2762deduced from the input file
2763@end enumerate
2764
2765@subheading Linker Input Architecture
2766
2767Ways to specify:
2768
2769@enumerate
2770@item
2771deduced from the input file
2772@end enumerate
2773
2774@subheading Linker Output Architecture
2775
2776Ways to specify:
2777
2778@enumerate
2779@item
2780script command @code{OUTPUT_ARCH}
2781(@pxref{Option Commands,,Option Commands,ld.info,Using LD})
2782
2783@item
2784the default architecture from the linker output target
2785(@pxref{Target Selection})
2786@end enumerate
2787
2788@node Linker Emulation Selection
2789@section Linker emulation selection
2790
2791A linker @dfn{emulation} is a ``personality'' of the linker, which gives
2792the linker default values for the other aspects of the target system.
2793In particular, it consists of
2794
2795@itemize @bullet
2796@item
2797the linker script
2798
2799@item
2800the target
2801
2802@item
2803several ``hook'' functions that are run at certain stages of the linking
2804process to do special things that some targets require
2805@end itemize
2806
2807The command to list valid linker emulation values is @samp{ld -V}.
2808
2809Sample values: @samp{hp300bsd}, @samp{mipslit}, @samp{sun4}.
2810
2811Ways to specify:
2812
2813@enumerate
2814@item
2815command line option: @samp{-m}
2816(@pxref{Options,,Options,ld.info,Using LD})
2817
2818@item
2819environment variable @code{LDEMULATION}
2820
2821@item
2822compiled-in @code{DEFAULT_EMULATION} from @file{Makefile},
2823which comes from @code{EMUL} in @file{config/@var{target}.mt}
2824@end enumerate
2825
2826@node Reporting Bugs
2827@chapter Reporting Bugs
2828@cindex bugs
2829@cindex reporting bugs
2830
2831Your bug reports play an essential role in making the binary utilities
2832reliable.
2833
2834Reporting a bug may help you by bringing a solution to your problem, or
2835it may not. But in any case the principal function of a bug report is
2836to help the entire community by making the next version of the binary
2837utilities work better. Bug reports are your contribution to their
2838maintenance.
2839
2840In order for a bug report to serve its purpose, you must include the
2841information that enables us to fix the bug.
2842
2843@menu
2844* Bug Criteria:: Have you found a bug?
2845* Bug Reporting:: How to report bugs
2846@end menu
2847
2848@node Bug Criteria
2849@section Have you found a bug?
2850@cindex bug criteria
2851
2852If you are not sure whether you have found a bug, here are some guidelines:
2853
2854@itemize @bullet
2855@cindex fatal signal
2856@cindex crash
2857@item
2858If a binary utility gets a fatal signal, for any input whatever, that is
2859a bug. Reliable utilities never crash.
2860
2861@cindex error on valid input
2862@item
2863If a binary utility produces an error message for valid input, that is a
2864bug.
2865
2866@item
2867If you are an experienced user of binary utilities, your suggestions for
2868improvement are welcome in any case.
2869@end itemize
2870
2871@node Bug Reporting
2872@section How to report bugs
2873@cindex bug reports
2874@cindex bugs, reporting
2875
2876A number of companies and individuals offer support for @sc{gnu}
2877products. If you obtained the binary utilities from a support
2878organization, we recommend you contact that organization first.
2879
2880You can find contact information for many support companies and
2881individuals in the file @file{etc/SERVICE} in the @sc{gnu} Emacs
2882distribution.
2883
2884In any event, we also recommend that you send bug reports for the binary
2885utilities to @samp{bug-gnu-utils@@gnu.org}.
2886
2887The fundamental principle of reporting bugs usefully is this:
2888@strong{report all the facts}. If you are not sure whether to state a
2889fact or leave it out, state it!
2890
2891Often people omit facts because they think they know what causes the
2892problem and assume that some details do not matter. Thus, you might
2893assume that the name of a file you use in an example does not matter.
2894Well, probably it does not, but one cannot be sure. Perhaps the bug is
2895a stray memory reference which happens to fetch from the location where
2896that pathname is stored in memory; perhaps, if the pathname were
2897different, the contents of that location would fool the utility into
2898doing the right thing despite the bug. Play it safe and give a
2899specific, complete example. That is the easiest thing for you to do,
2900and the most helpful.
2901
2902Keep in mind that the purpose of a bug report is to enable us to fix the bug if
2903it is new to us. Therefore, always write your bug reports on the assumption
2904that the bug has not been reported previously.
2905
2906Sometimes people give a few sketchy facts and ask, ``Does this ring a
2907bell?'' Those bug reports are useless, and we urge everyone to
2908@emph{refuse to respond to them} except to chide the sender to report
2909bugs properly.
2910
2911To enable us to fix the bug, you should include all these things:
2912
2913@itemize @bullet
2914@item
2915The version of the utility. Each utility announces it if you start it
2916with the @samp{--version} argument.
2917
2918Without this, we will not know whether there is any point in looking for
2919the bug in the current version of the binary utilities.
2920
2921@item
2922Any patches you may have applied to the source, including any patches
2923made to the @code{BFD} library.
2924
2925@item
2926The type of machine you are using, and the operating system name and
2927version number.
2928
2929@item
2930What compiler (and its version) was used to compile the utilities---e.g.
2931``@code{gcc-2.7}''.
2932
2933@item
2934The command arguments you gave the utility to observe the bug. To
2935guarantee you will not omit something important, list them all. A copy
2936of the Makefile (or the output from make) is sufficient.
2937
2938If we were to try to guess the arguments, we would probably guess wrong
2939and then we might not encounter the bug.
2940
2941@item
2942A complete input file, or set of input files, that will reproduce the
2943bug. If the utility is reading an object file or files, then it is
2944generally most helpful to send the actual object files, uuencoded if
757acbc5
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2945necessary to get them through the mail system. Note that
2946@samp{bug-gnu-utils@@gnu.org} is a mailing list, so you should avoid
2947sending very large files to it. Making the files available for
2948anonymous FTP is OK.
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2949
2950If the source files were produced exclusively using @sc{gnu} programs
2951(e.g., @code{gcc}, @code{gas}, and/or the @sc{gnu} @code{ld}), then it
2952may be OK to send the source files rather than the object files. In
2953this case, be sure to say exactly what version of @code{gcc}, or
2954whatever, was used to produce the object files. Also say how
2955@code{gcc}, or whatever, was configured.
2956
2957@item
2958A description of what behavior you observe that you believe is
2959incorrect. For example, ``It gets a fatal signal.''
2960
2961Of course, if the bug is that the utility gets a fatal signal, then we
2962will certainly notice it. But if the bug is incorrect output, we might
2963not notice unless it is glaringly wrong. You might as well not give us
2964a chance to make a mistake.
2965
2966Even if the problem you experience is a fatal signal, you should still
f20a759a 2967say so explicitly. Suppose something strange is going on, such as your
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2968copy of the utility is out of synch, or you have encountered a bug in
2969the C library on your system. (This has happened!) Your copy might
2970crash and ours would not. If you told us to expect a crash, then when
2971ours fails to crash, we would know that the bug was not happening for
2972us. If you had not told us to expect a crash, then we would not be able
2973to draw any conclusion from our observations.
2974
2975@item
2976If you wish to suggest changes to the source, send us context diffs, as
2977generated by @code{diff} with the @samp{-u}, @samp{-c}, or @samp{-p}
2978option. Always send diffs from the old file to the new file. If you
f20a759a
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2979wish to discuss something in the @code{ld} source, refer to it by
2980context, not by line number.
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2981
2982The line numbers in our development sources will not match those in your
2983sources. Your line numbers would convey no useful information to us.
2984@end itemize
2985
2986Here are some things that are not necessary:
2987
2988@itemize @bullet
2989@item
2990A description of the envelope of the bug.
2991
2992Often people who encounter a bug spend a lot of time investigating
2993which changes to the input file will make the bug go away and which
2994changes will not affect it.
2995
2996This is often time consuming and not very useful, because the way we
2997will find the bug is by running a single example under the debugger
2998with breakpoints, not by pure deduction from a series of examples.
2999We recommend that you save your time for something else.
3000
3001Of course, if you can find a simpler example to report @emph{instead}
3002of the original one, that is a convenience for us. Errors in the
3003output will be easier to spot, running under the debugger will take
3004less time, and so on.
3005
3006However, simplification is not vital; if you do not want to do this,
3007report the bug anyway and send us the entire test case you used.
3008
3009@item
3010A patch for the bug.
3011
3012A patch for the bug does help us if it is a good one. But do not omit
3013the necessary information, such as the test case, on the assumption that
3014a patch is all we need. We might see problems with your patch and decide
3015to fix the problem another way, or we might not understand it at all.
3016
3017Sometimes with programs as complicated as the binary utilities it is
3018very hard to construct an example that will make the program follow a
3019certain path through the code. If you do not send us the example, we
3020will not be able to construct one, so we will not be able to verify that
3021the bug is fixed.
3022
3023And if we cannot understand what bug you are trying to fix, or why your
3024patch should be an improvement, we will not install it. A test case will
3025help us to understand.
3026
3027@item
3028A guess about what the bug is or what it depends on.
3029
3030Such guesses are usually wrong. Even we cannot guess right about such
3031things without first using the debugger to find the facts.
3032@end itemize
3033
3034@node Index
3035@unnumbered Index
3036
3037@printindex cp
3038
3039@contents
3040@bye
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