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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, |
793c5807 | 4 | @c 2001, 2002, 2003, 2006, 2007, 2008 |
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5 | @c Free Software Foundation, Inc. |
6 | @c | |
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7 | @synindex fn cp |
8 | ||
9 | @ifinfo | |
10 | @format | |
11 | START-INFO-DIR-ENTRY | |
12 | * Bfd: (bfd). The Binary File Descriptor library. | |
13 | END-INFO-DIR-ENTRY | |
14 | @end format | |
15 | @end ifinfo | |
16 | ||
0e9517a9 | 17 | @copying |
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18 | This file documents the BFD library. |
19 | ||
793c5807 | 20 | Copyright @copyright{} 1991, 2000, 2001, 2003, 2006, 2007, 2008 Free Software Foundation, Inc. |
252b5132 | 21 | |
0e9517a9 | 22 | Permission is granted to copy, distribute and/or modify this document |
793c5807 | 23 | under the terms of the GNU Free Documentation License, Version 1.3 or |
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24 | any later version published by the Free Software Foundation; with the |
25 | Invariant Sections being ``GNU General Public License'' and ``Funding | |
26 | Free Software'', the Front-Cover texts being (a) (see below), and with | |
27 | the Back-Cover Texts being (b) (see below). A copy of the license is | |
28 | included in the section entitled ``GNU Free Documentation License''. | |
252b5132 | 29 | |
0e9517a9 | 30 | (a) The FSF's Front-Cover Text is: |
252b5132 | 31 | |
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32 | A GNU Manual |
33 | ||
34 | (b) The FSF's Back-Cover Text is: | |
35 | ||
36 | You have freedom to copy and modify this GNU Manual, like GNU | |
37 | software. Copies published by the Free Software Foundation raise | |
38 | funds for GNU development. | |
39 | @end copying | |
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40 | @iftex |
41 | @c@finalout | |
42 | @setchapternewpage on | |
43 | @c@setchapternewpage odd | |
44 | @settitle LIB BFD, the Binary File Descriptor Library | |
45 | @titlepage | |
46 | @title{libbfd} | |
47 | @subtitle{The Binary File Descriptor Library} | |
48 | @sp 1 | |
b45619c0 | 49 | @subtitle First Edition---BFD version < 3.0 % Since no product is stable before version 3.0 :-) |
07d8a891 | 50 | @subtitle Original Document Created: April 1991 |
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51 | @author {Steve Chamberlain} |
52 | @author {Cygnus Support} | |
53 | @page | |
54 | ||
55 | @tex | |
56 | \def\$#1${{#1}} % Kluge: collect RCS revision info without $...$ | |
27c5d6c9 | 57 | \xdef\manvers{1.5} % For use in headers, footers too |
252b5132 | 58 | {\parskip=0pt |
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59 | \hfill Free Software Foundation\par |
60 | \hfill sac\@www.gnu.org\par | |
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61 | \hfill {\it BFD}, \manvers\par |
62 | \hfill \TeX{}info \texinfoversion\par | |
63 | } | |
64 | \global\parindent=0pt % Steve likes it this way | |
65 | @end tex | |
66 | ||
67 | @vskip 0pt plus 1filll | |
793c5807 | 68 | Copyright @copyright{} 1991, 2001, 2003, 2006, 2008 Free Software Foundation, Inc. |
252b5132 | 69 | |
4a8e467a | 70 | Permission is granted to copy, distribute and/or modify this document |
793c5807 | 71 | under the terms of the GNU Free Documentation License, Version 1.3 |
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72 | or any later version published by the Free Software Foundation; |
73 | with no Invariant Sections, with no Front-Cover Texts, and with no | |
74 | Back-Cover Texts. A copy of the license is included in the | |
53954f5e | 75 | section entitled ``GNU Free Documentation License''. |
252b5132 | 76 | |
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77 | @end titlepage |
78 | @end iftex | |
4ecceb71 | 79 | @contents |
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80 | |
81 | @node Top, Overview, (dir), (dir) | |
82 | @ifinfo | |
83 | This file documents the binary file descriptor library libbfd. | |
84 | @end ifinfo | |
85 | ||
86 | @menu | |
87 | * Overview:: Overview of BFD | |
88 | * BFD front end:: BFD front end | |
89 | * BFD back ends:: BFD back ends | |
4a8e467a | 90 | * GNU Free Documentation License:: GNU Free Documentation License |
370b66a1 | 91 | * BFD Index:: BFD Index |
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92 | @end menu |
93 | ||
94 | @node Overview, BFD front end, Top, Top | |
95 | @chapter Introduction | |
96 | @cindex BFD | |
97 | @cindex what is it? | |
98 | BFD is a package which allows applications to use the | |
99 | same routines to operate on object files whatever the object file | |
100 | format. A new object file format can be supported simply by | |
101 | creating a new BFD back end and adding it to the library. | |
102 | ||
103 | BFD is split into two parts: the front end, and the back ends (one for | |
104 | each object file format). | |
105 | @itemize @bullet | |
106 | @item The front end of BFD provides the interface to the user. It manages | |
107 | memory and various canonical data structures. The front end also | |
108 | decides which back end to use and when to call back end routines. | |
109 | @item The back ends provide BFD its view of the real world. Each back | |
110 | end provides a set of calls which the BFD front end can use to maintain | |
111 | its canonical form. The back ends also may keep around information for | |
112 | their own use, for greater efficiency. | |
113 | @end itemize | |
114 | @menu | |
115 | * History:: History | |
116 | * How It Works:: How It Works | |
117 | * What BFD Version 2 Can Do:: What BFD Version 2 Can Do | |
118 | @end menu | |
119 | ||
120 | @node History, How It Works, Overview, Overview | |
121 | @section History | |
122 | ||
123 | One spur behind BFD was the desire, on the part of the GNU 960 team at | |
124 | Intel Oregon, for interoperability of applications on their COFF and | |
125 | b.out file formats. Cygnus was providing GNU support for the team, and | |
126 | was contracted to provide the required functionality. | |
127 | ||
128 | The name came from a conversation David Wallace was having with Richard | |
129 | Stallman about the library: RMS said that it would be quite hard---David | |
130 | said ``BFD''. Stallman was right, but the name stuck. | |
131 | ||
132 | At the same time, Ready Systems wanted much the same thing, but for | |
133 | different object file formats: IEEE-695, Oasys, Srecords, a.out and 68k | |
134 | coff. | |
135 | ||
136 | BFD was first implemented by members of Cygnus Support; Steve | |
137 | Chamberlain (@code{sac@@cygnus.com}), John Gilmore | |
138 | (@code{gnu@@cygnus.com}), K. Richard Pixley (@code{rich@@cygnus.com}) | |
139 | and David Henkel-Wallace (@code{gumby@@cygnus.com}). | |
140 | ||
141 | ||
142 | ||
143 | @node How It Works, What BFD Version 2 Can Do, History, Overview | |
144 | @section How To Use BFD | |
145 | ||
146 | To use the library, include @file{bfd.h} and link with @file{libbfd.a}. | |
147 | ||
148 | BFD provides a common interface to the parts of an object file | |
149 | for a calling application. | |
150 | ||
b45619c0 | 151 | When an application successfully opens a target file (object, archive, or |
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152 | whatever), a pointer to an internal structure is returned. This pointer |
153 | points to a structure called @code{bfd}, described in | |
154 | @file{bfd.h}. Our convention is to call this pointer a BFD, and | |
155 | instances of it within code @code{abfd}. All operations on | |
156 | the target object file are applied as methods to the BFD. The mapping is | |
157 | defined within @code{bfd.h} in a set of macros, all beginning | |
158 | with @samp{bfd_} to reduce namespace pollution. | |
159 | ||
160 | For example, this sequence does what you would probably expect: | |
161 | return the number of sections in an object file attached to a BFD | |
162 | @code{abfd}. | |
163 | ||
53954f5e | 164 | @example |
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165 | @c @cartouche |
166 | #include "bfd.h" | |
167 | ||
53954f5e | 168 | unsigned int number_of_sections (abfd) |
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169 | bfd *abfd; |
170 | @{ | |
53954f5e | 171 | return bfd_count_sections (abfd); |
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172 | @} |
173 | @c @end cartouche | |
53954f5e | 174 | @end example |
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175 | |
176 | The abstraction used within BFD is that an object file has: | |
177 | ||
178 | @itemize @bullet | |
179 | @item | |
180 | a header, | |
181 | @item | |
182 | a number of sections containing raw data (@pxref{Sections}), | |
183 | @item | |
184 | a set of relocations (@pxref{Relocations}), and | |
185 | @item | |
186 | some symbol information (@pxref{Symbols}). | |
187 | @end itemize | |
188 | @noindent | |
189 | Also, BFDs opened for archives have the additional attribute of an index | |
190 | and contain subordinate BFDs. This approach is fine for a.out and coff, | |
191 | but loses efficiency when applied to formats such as S-records and | |
192 | IEEE-695. | |
193 | ||
194 | @node What BFD Version 2 Can Do, , How It Works, Overview | |
195 | @section What BFD Version 2 Can Do | |
196 | @include bfdsumm.texi | |
197 | ||
198 | @node BFD front end, BFD back ends, Overview, Top | |
53954f5e | 199 | @chapter BFD Front End |
252b5132 | 200 | @include bfdt.texi |
93509525 | 201 | @include bfdio.texi |
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202 | |
203 | @menu | |
204 | * Memory Usage:: | |
205 | * Initialization:: | |
206 | * Sections:: | |
207 | * Symbols:: | |
208 | * Archives:: | |
209 | * Formats:: | |
210 | * Relocations:: | |
211 | * Core Files:: | |
212 | * Targets:: | |
213 | * Architectures:: | |
214 | * Opening and Closing:: | |
215 | * Internal:: | |
216 | * File Caching:: | |
217 | * Linker Functions:: | |
218 | * Hash Tables:: | |
219 | @end menu | |
220 | ||
221 | @node Memory Usage, Initialization, BFD front end, BFD front end | |
53954f5e | 222 | @section Memory Usage |
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223 | BFD keeps all of its internal structures in obstacks. There is one obstack |
224 | per open BFD file, into which the current state is stored. When a BFD is | |
225 | closed, the obstack is deleted, and so everything which has been | |
226 | allocated by BFD for the closing file is thrown away. | |
227 | ||
228 | BFD does not free anything created by an application, but pointers into | |
229 | @code{bfd} structures become invalid on a @code{bfd_close}; for example, | |
230 | after a @code{bfd_close} the vector passed to | |
231 | @code{bfd_canonicalize_symtab} is still around, since it has been | |
232 | allocated by the application, but the data that it pointed to are | |
233 | lost. | |
234 | ||
235 | The general rule is to not close a BFD until all operations dependent | |
236 | upon data from the BFD have been completed, or all the data from within | |
237 | the file has been copied. To help with the management of memory, there | |
238 | is a function (@code{bfd_alloc_size}) which returns the number of bytes | |
239 | in obstacks associated with the supplied BFD. This could be used to | |
240 | select the greediest open BFD, close it to reclaim the memory, perform | |
241 | some operation and reopen the BFD again, to get a fresh copy of the data | |
242 | structures. | |
243 | ||
244 | @node Initialization, Sections, Memory Usage, BFD front end | |
245 | @include init.texi | |
246 | ||
247 | @node Sections, Symbols, Initialization, BFD front end | |
248 | @include section.texi | |
249 | ||
250 | @node Symbols, Archives, Sections, BFD front end | |
251 | @include syms.texi | |
252 | ||
253 | @node Archives, Formats, Symbols, BFD front end | |
254 | @include archive.texi | |
255 | ||
256 | @node Formats, Relocations, Archives, BFD front end | |
257 | @include format.texi | |
258 | ||
259 | @node Relocations, Core Files, Formats, BFD front end | |
260 | @include reloc.texi | |
261 | ||
262 | @node Core Files, Targets, Relocations, BFD front end | |
263 | @include core.texi | |
264 | ||
265 | @node Targets, Architectures, Core Files, BFD front end | |
266 | @include targets.texi | |
267 | ||
268 | @node Architectures, Opening and Closing, Targets, BFD front end | |
269 | @include archures.texi | |
270 | ||
271 | @node Opening and Closing, Internal, Architectures, BFD front end | |
272 | @include opncls.texi | |
273 | ||
274 | @node Internal, File Caching, Opening and Closing, BFD front end | |
275 | @include libbfd.texi | |
276 | ||
277 | @node File Caching, Linker Functions, Internal, BFD front end | |
278 | @include cache.texi | |
279 | ||
280 | @node Linker Functions, Hash Tables, File Caching, BFD front end | |
281 | @include linker.texi | |
282 | ||
283 | @node Hash Tables, , Linker Functions, BFD front end | |
284 | @include hash.texi | |
285 | ||
4a8e467a | 286 | @node BFD back ends, GNU Free Documentation License, BFD front end, Top |
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287 | @chapter BFD back ends |
288 | @menu | |
289 | * What to Put Where:: | |
290 | * aout :: a.out backends | |
291 | * coff :: coff backends | |
292 | * elf :: elf backends | |
3c3bdf30 | 293 | * mmo :: mmo backend |
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294 | @ignore |
295 | * oasys :: oasys backends | |
296 | * ieee :: ieee backend | |
297 | * srecord :: s-record backend | |
298 | @end ignore | |
299 | @end menu | |
300 | @node What to Put Where, aout, BFD back ends, BFD back ends | |
9cd73268 | 301 | @section What to Put Where |
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302 | All of BFD lives in one directory. |
303 | ||
304 | @node aout, coff, What to Put Where, BFD back ends | |
305 | @include aoutx.texi | |
306 | ||
307 | @node coff, elf, aout, BFD back ends | |
308 | @include coffcode.texi | |
309 | ||
3c3bdf30 | 310 | @node elf, mmo, coff, BFD back ends |
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311 | @include elf.texi |
312 | @c Leave this out until the file has some actual contents... | |
313 | @c @include elfcode.texi | |
314 | ||
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315 | @node mmo, , elf, BFD back ends |
316 | @include mmo.texi | |
317 | ||
370b66a1 | 318 | @node GNU Free Documentation License, BFD Index, BFD back ends, Top |
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319 | @include fdl.texi |
320 | ||
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321 | @node BFD Index, , GNU Free Documentation License, Top |
322 | @unnumbered BFD Index | |
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323 | @printindex cp |
324 | ||
325 | @tex | |
326 | % I think something like @colophon should be in texinfo. In the | |
327 | % meantime: | |
328 | \long\def\colophon{\hbox to0pt{}\vfill | |
329 | \centerline{The body of this manual is set in} | |
330 | \centerline{\fontname\tenrm,} | |
331 | \centerline{with headings in {\bf\fontname\tenbf}} | |
332 | \centerline{and examples in {\tt\fontname\tentt}.} | |
333 | \centerline{{\it\fontname\tenit\/} and} | |
334 | \centerline{{\sl\fontname\tensl\/}} | |
335 | \centerline{are used for emphasis.}\vfill} | |
336 | \page\colophon | |
337 | % Blame: doc@cygnus.com, 28mar91. | |
338 | @end tex | |
339 | ||
252b5132 | 340 | @bye |