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1 | \input texinfo.tex |
2 | @setfilename bfd.info | |
9553c638 | 3 | @c Copyright 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1997, 2000, |
aa820537 | 4 | @c 2001, 2002, 2003, 2006, 2007, 2008, 2009 |
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5 | @c Free Software Foundation, Inc. |
6 | @c | |
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7 | @synindex fn cp |
8 | ||
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9 | @ifnottex |
10 | @dircategory Software development | |
11 | @direntry | |
252b5132 | 12 | * Bfd: (bfd). The Binary File Descriptor library. |
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13 | @end direntry |
14 | @end ifnottex | |
252b5132 | 15 | |
0e9517a9 | 16 | @copying |
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17 | This file documents the BFD library. |
18 | ||
793c5807 | 19 | Copyright @copyright{} 1991, 2000, 2001, 2003, 2006, 2007, 2008 Free Software Foundation, Inc. |
252b5132 | 20 | |
0e9517a9 | 21 | Permission is granted to copy, distribute and/or modify this document |
793c5807 | 22 | under the terms of the GNU Free Documentation License, Version 1.3 or |
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23 | any later version published by the Free Software Foundation; with the |
24 | Invariant Sections being ``GNU General Public License'' and ``Funding | |
25 | Free Software'', the Front-Cover texts being (a) (see below), and with | |
26 | the Back-Cover Texts being (b) (see below). A copy of the license is | |
27 | included in the section entitled ``GNU Free Documentation License''. | |
252b5132 | 28 | |
0e9517a9 | 29 | (a) The FSF's Front-Cover Text is: |
252b5132 | 30 | |
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31 | A GNU Manual |
32 | ||
33 | (b) The FSF's Back-Cover Text is: | |
34 | ||
35 | You have freedom to copy and modify this GNU Manual, like GNU | |
36 | software. Copies published by the Free Software Foundation raise | |
37 | funds for GNU development. | |
38 | @end copying | |
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39 | @iftex |
40 | @c@finalout | |
41 | @setchapternewpage on | |
42 | @c@setchapternewpage odd | |
43 | @settitle LIB BFD, the Binary File Descriptor Library | |
44 | @titlepage | |
45 | @title{libbfd} | |
46 | @subtitle{The Binary File Descriptor Library} | |
47 | @sp 1 | |
b45619c0 | 48 | @subtitle First Edition---BFD version < 3.0 % Since no product is stable before version 3.0 :-) |
07d8a891 | 49 | @subtitle Original Document Created: April 1991 |
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50 | @author {Steve Chamberlain} |
51 | @author {Cygnus Support} | |
52 | @page | |
53 | ||
54 | @tex | |
55 | \def\$#1${{#1}} % Kluge: collect RCS revision info without $...$ | |
27c5d6c9 | 56 | \xdef\manvers{1.5} % For use in headers, footers too |
252b5132 | 57 | {\parskip=0pt |
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58 | \hfill Free Software Foundation\par |
59 | \hfill sac\@www.gnu.org\par | |
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60 | \hfill {\it BFD}, \manvers\par |
61 | \hfill \TeX{}info \texinfoversion\par | |
62 | } | |
63 | \global\parindent=0pt % Steve likes it this way | |
64 | @end tex | |
65 | ||
66 | @vskip 0pt plus 1filll | |
793c5807 | 67 | Copyright @copyright{} 1991, 2001, 2003, 2006, 2008 Free Software Foundation, Inc. |
252b5132 | 68 | |
4a8e467a | 69 | Permission is granted to copy, distribute and/or modify this document |
793c5807 | 70 | under the terms of the GNU Free Documentation License, Version 1.3 |
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71 | or any later version published by the Free Software Foundation; |
72 | with no Invariant Sections, with no Front-Cover Texts, and with no | |
73 | Back-Cover Texts. A copy of the license is included in the | |
53954f5e | 74 | section entitled ``GNU Free Documentation License''. |
252b5132 | 75 | |
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76 | @end titlepage |
77 | @end iftex | |
4ecceb71 | 78 | @contents |
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79 | |
80 | @node Top, Overview, (dir), (dir) | |
81 | @ifinfo | |
82 | This file documents the binary file descriptor library libbfd. | |
83 | @end ifinfo | |
84 | ||
85 | @menu | |
86 | * Overview:: Overview of BFD | |
87 | * BFD front end:: BFD front end | |
88 | * BFD back ends:: BFD back ends | |
4a8e467a | 89 | * GNU Free Documentation License:: GNU Free Documentation License |
370b66a1 | 90 | * BFD Index:: BFD Index |
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91 | @end menu |
92 | ||
93 | @node Overview, BFD front end, Top, Top | |
94 | @chapter Introduction | |
95 | @cindex BFD | |
96 | @cindex what is it? | |
97 | BFD is a package which allows applications to use the | |
98 | same routines to operate on object files whatever the object file | |
99 | format. A new object file format can be supported simply by | |
100 | creating a new BFD back end and adding it to the library. | |
101 | ||
102 | BFD is split into two parts: the front end, and the back ends (one for | |
103 | each object file format). | |
104 | @itemize @bullet | |
105 | @item The front end of BFD provides the interface to the user. It manages | |
106 | memory and various canonical data structures. The front end also | |
107 | decides which back end to use and when to call back end routines. | |
108 | @item The back ends provide BFD its view of the real world. Each back | |
109 | end provides a set of calls which the BFD front end can use to maintain | |
110 | its canonical form. The back ends also may keep around information for | |
111 | their own use, for greater efficiency. | |
112 | @end itemize | |
113 | @menu | |
114 | * History:: History | |
115 | * How It Works:: How It Works | |
116 | * What BFD Version 2 Can Do:: What BFD Version 2 Can Do | |
117 | @end menu | |
118 | ||
119 | @node History, How It Works, Overview, Overview | |
120 | @section History | |
121 | ||
122 | One spur behind BFD was the desire, on the part of the GNU 960 team at | |
123 | Intel Oregon, for interoperability of applications on their COFF and | |
124 | b.out file formats. Cygnus was providing GNU support for the team, and | |
125 | was contracted to provide the required functionality. | |
126 | ||
127 | The name came from a conversation David Wallace was having with Richard | |
128 | Stallman about the library: RMS said that it would be quite hard---David | |
129 | said ``BFD''. Stallman was right, but the name stuck. | |
130 | ||
131 | At the same time, Ready Systems wanted much the same thing, but for | |
132 | different object file formats: IEEE-695, Oasys, Srecords, a.out and 68k | |
133 | coff. | |
134 | ||
135 | BFD was first implemented by members of Cygnus Support; Steve | |
136 | Chamberlain (@code{sac@@cygnus.com}), John Gilmore | |
137 | (@code{gnu@@cygnus.com}), K. Richard Pixley (@code{rich@@cygnus.com}) | |
138 | and David Henkel-Wallace (@code{gumby@@cygnus.com}). | |
139 | ||
140 | ||
141 | ||
142 | @node How It Works, What BFD Version 2 Can Do, History, Overview | |
143 | @section How To Use BFD | |
144 | ||
145 | To use the library, include @file{bfd.h} and link with @file{libbfd.a}. | |
146 | ||
147 | BFD provides a common interface to the parts of an object file | |
148 | for a calling application. | |
149 | ||
b45619c0 | 150 | When an application successfully opens a target file (object, archive, or |
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151 | whatever), a pointer to an internal structure is returned. This pointer |
152 | points to a structure called @code{bfd}, described in | |
153 | @file{bfd.h}. Our convention is to call this pointer a BFD, and | |
154 | instances of it within code @code{abfd}. All operations on | |
155 | the target object file are applied as methods to the BFD. The mapping is | |
156 | defined within @code{bfd.h} in a set of macros, all beginning | |
157 | with @samp{bfd_} to reduce namespace pollution. | |
158 | ||
159 | For example, this sequence does what you would probably expect: | |
160 | return the number of sections in an object file attached to a BFD | |
161 | @code{abfd}. | |
162 | ||
53954f5e | 163 | @example |
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164 | @c @cartouche |
165 | #include "bfd.h" | |
166 | ||
53954f5e | 167 | unsigned int number_of_sections (abfd) |
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168 | bfd *abfd; |
169 | @{ | |
53954f5e | 170 | return bfd_count_sections (abfd); |
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171 | @} |
172 | @c @end cartouche | |
53954f5e | 173 | @end example |
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174 | |
175 | The abstraction used within BFD is that an object file has: | |
176 | ||
177 | @itemize @bullet | |
178 | @item | |
179 | a header, | |
180 | @item | |
181 | a number of sections containing raw data (@pxref{Sections}), | |
182 | @item | |
183 | a set of relocations (@pxref{Relocations}), and | |
184 | @item | |
185 | some symbol information (@pxref{Symbols}). | |
186 | @end itemize | |
187 | @noindent | |
188 | Also, BFDs opened for archives have the additional attribute of an index | |
189 | and contain subordinate BFDs. This approach is fine for a.out and coff, | |
190 | but loses efficiency when applied to formats such as S-records and | |
191 | IEEE-695. | |
192 | ||
193 | @node What BFD Version 2 Can Do, , How It Works, Overview | |
194 | @section What BFD Version 2 Can Do | |
195 | @include bfdsumm.texi | |
196 | ||
197 | @node BFD front end, BFD back ends, Overview, Top | |
53954f5e | 198 | @chapter BFD Front End |
252b5132 | 199 | @include bfdt.texi |
93509525 | 200 | @include bfdio.texi |
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201 | |
202 | @menu | |
203 | * Memory Usage:: | |
204 | * Initialization:: | |
205 | * Sections:: | |
206 | * Symbols:: | |
207 | * Archives:: | |
208 | * Formats:: | |
209 | * Relocations:: | |
210 | * Core Files:: | |
211 | * Targets:: | |
212 | * Architectures:: | |
213 | * Opening and Closing:: | |
214 | * Internal:: | |
215 | * File Caching:: | |
216 | * Linker Functions:: | |
217 | * Hash Tables:: | |
218 | @end menu | |
219 | ||
220 | @node Memory Usage, Initialization, BFD front end, BFD front end | |
53954f5e | 221 | @section Memory Usage |
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222 | BFD keeps all of its internal structures in obstacks. There is one obstack |
223 | per open BFD file, into which the current state is stored. When a BFD is | |
224 | closed, the obstack is deleted, and so everything which has been | |
225 | allocated by BFD for the closing file is thrown away. | |
226 | ||
227 | BFD does not free anything created by an application, but pointers into | |
228 | @code{bfd} structures become invalid on a @code{bfd_close}; for example, | |
229 | after a @code{bfd_close} the vector passed to | |
230 | @code{bfd_canonicalize_symtab} is still around, since it has been | |
231 | allocated by the application, but the data that it pointed to are | |
232 | lost. | |
233 | ||
234 | The general rule is to not close a BFD until all operations dependent | |
235 | upon data from the BFD have been completed, or all the data from within | |
236 | the file has been copied. To help with the management of memory, there | |
237 | is a function (@code{bfd_alloc_size}) which returns the number of bytes | |
238 | in obstacks associated with the supplied BFD. This could be used to | |
239 | select the greediest open BFD, close it to reclaim the memory, perform | |
240 | some operation and reopen the BFD again, to get a fresh copy of the data | |
241 | structures. | |
242 | ||
243 | @node Initialization, Sections, Memory Usage, BFD front end | |
244 | @include init.texi | |
245 | ||
246 | @node Sections, Symbols, Initialization, BFD front end | |
247 | @include section.texi | |
248 | ||
249 | @node Symbols, Archives, Sections, BFD front end | |
250 | @include syms.texi | |
251 | ||
252 | @node Archives, Formats, Symbols, BFD front end | |
253 | @include archive.texi | |
254 | ||
255 | @node Formats, Relocations, Archives, BFD front end | |
256 | @include format.texi | |
257 | ||
258 | @node Relocations, Core Files, Formats, BFD front end | |
259 | @include reloc.texi | |
260 | ||
261 | @node Core Files, Targets, Relocations, BFD front end | |
262 | @include core.texi | |
263 | ||
264 | @node Targets, Architectures, Core Files, BFD front end | |
265 | @include targets.texi | |
266 | ||
267 | @node Architectures, Opening and Closing, Targets, BFD front end | |
268 | @include archures.texi | |
269 | ||
270 | @node Opening and Closing, Internal, Architectures, BFD front end | |
271 | @include opncls.texi | |
272 | ||
273 | @node Internal, File Caching, Opening and Closing, BFD front end | |
274 | @include libbfd.texi | |
275 | ||
276 | @node File Caching, Linker Functions, Internal, BFD front end | |
277 | @include cache.texi | |
278 | ||
279 | @node Linker Functions, Hash Tables, File Caching, BFD front end | |
280 | @include linker.texi | |
281 | ||
282 | @node Hash Tables, , Linker Functions, BFD front end | |
283 | @include hash.texi | |
284 | ||
4a8e467a | 285 | @node BFD back ends, GNU Free Documentation License, BFD front end, Top |
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286 | @chapter BFD back ends |
287 | @menu | |
288 | * What to Put Where:: | |
289 | * aout :: a.out backends | |
290 | * coff :: coff backends | |
291 | * elf :: elf backends | |
3c3bdf30 | 292 | * mmo :: mmo backend |
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293 | @ignore |
294 | * oasys :: oasys backends | |
295 | * ieee :: ieee backend | |
296 | * srecord :: s-record backend | |
297 | @end ignore | |
298 | @end menu | |
299 | @node What to Put Where, aout, BFD back ends, BFD back ends | |
9cd73268 | 300 | @section What to Put Where |
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301 | All of BFD lives in one directory. |
302 | ||
303 | @node aout, coff, What to Put Where, BFD back ends | |
304 | @include aoutx.texi | |
305 | ||
306 | @node coff, elf, aout, BFD back ends | |
307 | @include coffcode.texi | |
308 | ||
3c3bdf30 | 309 | @node elf, mmo, coff, BFD back ends |
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310 | @include elf.texi |
311 | @c Leave this out until the file has some actual contents... | |
312 | @c @include elfcode.texi | |
313 | ||
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314 | @node mmo, , elf, BFD back ends |
315 | @include mmo.texi | |
316 | ||
370b66a1 | 317 | @node GNU Free Documentation License, BFD Index, BFD back ends, Top |
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318 | @include fdl.texi |
319 | ||
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320 | @node BFD Index, , GNU Free Documentation License, Top |
321 | @unnumbered BFD Index | |
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322 | @printindex cp |
323 | ||
324 | @tex | |
325 | % I think something like @colophon should be in texinfo. In the | |
326 | % meantime: | |
327 | \long\def\colophon{\hbox to0pt{}\vfill | |
328 | \centerline{The body of this manual is set in} | |
329 | \centerline{\fontname\tenrm,} | |
330 | \centerline{with headings in {\bf\fontname\tenbf}} | |
331 | \centerline{and examples in {\tt\fontname\tentt}.} | |
332 | \centerline{{\it\fontname\tenit\/} and} | |
333 | \centerline{{\sl\fontname\tensl\/}} | |
334 | \centerline{are used for emphasis.}\vfill} | |
335 | \page\colophon | |
336 | % Blame: doc@cygnus.com, 28mar91. | |
337 | @end tex | |
338 | ||
252b5132 | 339 | @bye |