Commit | Line | Data |
---|---|---|
252b5132 RH |
1 | \input texinfo.tex |
2 | @setfilename bfd.info | |
9553c638 AM |
3 | @c Copyright 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1997, 2000, |
4 | @c 2001, 2002, 2003 | |
7898deda NC |
5 | @c Free Software Foundation, Inc. |
6 | @c | |
252b5132 RH |
7 | @tex |
8 | % NOTE LOCAL KLUGE TO AVOID TOO MUCH WHITESPACE | |
9 | \global\long\def\example{% | |
10 | \begingroup | |
11 | \let\aboveenvbreak=\par | |
12 | \let\afterenvbreak=\par | |
13 | \parskip=0pt | |
14 | \lisp} | |
15 | \global\long\def\Eexample{% | |
16 | \Elisp | |
17 | \endgroup | |
18 | \vskip -\parskip% to cancel out effect of following \par | |
19 | } | |
20 | @end tex | |
21 | @synindex fn cp | |
22 | ||
23 | @ifinfo | |
24 | @format | |
25 | START-INFO-DIR-ENTRY | |
26 | * Bfd: (bfd). The Binary File Descriptor library. | |
27 | END-INFO-DIR-ENTRY | |
28 | @end format | |
29 | @end ifinfo | |
30 | ||
31 | @ifinfo | |
32 | This file documents the BFD library. | |
33 | ||
53954f5e | 34 | Copyright (C) 1991, 2000, 2001, 2003 Free Software Foundation, Inc. |
252b5132 | 35 | |
4a8e467a NC |
36 | Permission is granted to copy, distribute and/or modify this document |
37 | under the terms of the GNU Free Documentation License, Version 1.1 | |
38 | or any later version published by the Free Software Foundation; | |
39 | with no Invariant Sections, with no Front-Cover Texts, and with no | |
40 | Back-Cover Texts. A copy of the license is included in the | |
53954f5e | 41 | section entitled ``GNU Free Documentation License''. |
252b5132 RH |
42 | |
43 | @ignore | |
44 | Permission is granted to process this file through Tex and print the | |
45 | results, provided the printed document carries copying permission | |
46 | notice identical to this one except for the removal of this paragraph | |
47 | (this paragraph not being relevant to the printed manual). | |
48 | ||
49 | @end ignore | |
252b5132 RH |
50 | @end ifinfo |
51 | @iftex | |
52 | @c@finalout | |
53 | @setchapternewpage on | |
54 | @c@setchapternewpage odd | |
55 | @settitle LIB BFD, the Binary File Descriptor Library | |
56 | @titlepage | |
57 | @title{libbfd} | |
58 | @subtitle{The Binary File Descriptor Library} | |
59 | @sp 1 | |
07d8a891 NC |
60 | @subtitle First Edition---BFD version < 3.0 % Since no product is stable berfore version 3.0 :-) |
61 | @subtitle Original Document Created: April 1991 | |
252b5132 RH |
62 | @author {Steve Chamberlain} |
63 | @author {Cygnus Support} | |
64 | @page | |
65 | ||
66 | @tex | |
67 | \def\$#1${{#1}} % Kluge: collect RCS revision info without $...$ | |
27c5d6c9 | 68 | \xdef\manvers{1.5} % For use in headers, footers too |
252b5132 | 69 | {\parskip=0pt |
07d8a891 NC |
70 | \hfill Free Software Foundation\par |
71 | \hfill sac\@www.gnu.org\par | |
252b5132 RH |
72 | \hfill {\it BFD}, \manvers\par |
73 | \hfill \TeX{}info \texinfoversion\par | |
74 | } | |
75 | \global\parindent=0pt % Steve likes it this way | |
76 | @end tex | |
77 | ||
78 | @vskip 0pt plus 1filll | |
53954f5e | 79 | Copyright @copyright{} 1991, 2001, 2003 Free Software Foundation, Inc. |
252b5132 | 80 | |
4a8e467a NC |
81 | Permission is granted to copy, distribute and/or modify this document |
82 | under the terms of the GNU Free Documentation License, Version 1.1 | |
83 | or any later version published by the Free Software Foundation; | |
84 | with no Invariant Sections, with no Front-Cover Texts, and with no | |
85 | Back-Cover Texts. A copy of the license is included in the | |
53954f5e | 86 | section entitled ``GNU Free Documentation License''. |
252b5132 | 87 | |
252b5132 RH |
88 | @end titlepage |
89 | @end iftex | |
90 | ||
91 | @node Top, Overview, (dir), (dir) | |
92 | @ifinfo | |
93 | This file documents the binary file descriptor library libbfd. | |
94 | @end ifinfo | |
95 | ||
96 | @menu | |
97 | * Overview:: Overview of BFD | |
98 | * BFD front end:: BFD front end | |
99 | * BFD back ends:: BFD back ends | |
4a8e467a | 100 | * GNU Free Documentation License:: GNU Free Documentation License |
252b5132 RH |
101 | * Index:: Index |
102 | @end menu | |
103 | ||
104 | @node Overview, BFD front end, Top, Top | |
105 | @chapter Introduction | |
106 | @cindex BFD | |
107 | @cindex what is it? | |
108 | BFD is a package which allows applications to use the | |
109 | same routines to operate on object files whatever the object file | |
110 | format. A new object file format can be supported simply by | |
111 | creating a new BFD back end and adding it to the library. | |
112 | ||
113 | BFD is split into two parts: the front end, and the back ends (one for | |
114 | each object file format). | |
115 | @itemize @bullet | |
116 | @item The front end of BFD provides the interface to the user. It manages | |
117 | memory and various canonical data structures. The front end also | |
118 | decides which back end to use and when to call back end routines. | |
119 | @item The back ends provide BFD its view of the real world. Each back | |
120 | end provides a set of calls which the BFD front end can use to maintain | |
121 | its canonical form. The back ends also may keep around information for | |
122 | their own use, for greater efficiency. | |
123 | @end itemize | |
124 | @menu | |
125 | * History:: History | |
126 | * How It Works:: How It Works | |
127 | * What BFD Version 2 Can Do:: What BFD Version 2 Can Do | |
128 | @end menu | |
129 | ||
130 | @node History, How It Works, Overview, Overview | |
131 | @section History | |
132 | ||
133 | One spur behind BFD was the desire, on the part of the GNU 960 team at | |
134 | Intel Oregon, for interoperability of applications on their COFF and | |
135 | b.out file formats. Cygnus was providing GNU support for the team, and | |
136 | was contracted to provide the required functionality. | |
137 | ||
138 | The name came from a conversation David Wallace was having with Richard | |
139 | Stallman about the library: RMS said that it would be quite hard---David | |
140 | said ``BFD''. Stallman was right, but the name stuck. | |
141 | ||
142 | At the same time, Ready Systems wanted much the same thing, but for | |
143 | different object file formats: IEEE-695, Oasys, Srecords, a.out and 68k | |
144 | coff. | |
145 | ||
146 | BFD was first implemented by members of Cygnus Support; Steve | |
147 | Chamberlain (@code{sac@@cygnus.com}), John Gilmore | |
148 | (@code{gnu@@cygnus.com}), K. Richard Pixley (@code{rich@@cygnus.com}) | |
149 | and David Henkel-Wallace (@code{gumby@@cygnus.com}). | |
150 | ||
151 | ||
152 | ||
153 | @node How It Works, What BFD Version 2 Can Do, History, Overview | |
154 | @section How To Use BFD | |
155 | ||
156 | To use the library, include @file{bfd.h} and link with @file{libbfd.a}. | |
157 | ||
158 | BFD provides a common interface to the parts of an object file | |
159 | for a calling application. | |
160 | ||
161 | When an application sucessfully opens a target file (object, archive, or | |
162 | whatever), a pointer to an internal structure is returned. This pointer | |
163 | points to a structure called @code{bfd}, described in | |
164 | @file{bfd.h}. Our convention is to call this pointer a BFD, and | |
165 | instances of it within code @code{abfd}. All operations on | |
166 | the target object file are applied as methods to the BFD. The mapping is | |
167 | defined within @code{bfd.h} in a set of macros, all beginning | |
168 | with @samp{bfd_} to reduce namespace pollution. | |
169 | ||
170 | For example, this sequence does what you would probably expect: | |
171 | return the number of sections in an object file attached to a BFD | |
172 | @code{abfd}. | |
173 | ||
53954f5e | 174 | @example |
252b5132 RH |
175 | @c @cartouche |
176 | #include "bfd.h" | |
177 | ||
53954f5e | 178 | unsigned int number_of_sections (abfd) |
252b5132 RH |
179 | bfd *abfd; |
180 | @{ | |
53954f5e | 181 | return bfd_count_sections (abfd); |
252b5132 RH |
182 | @} |
183 | @c @end cartouche | |
53954f5e | 184 | @end example |
252b5132 RH |
185 | |
186 | The abstraction used within BFD is that an object file has: | |
187 | ||
188 | @itemize @bullet | |
189 | @item | |
190 | a header, | |
191 | @item | |
192 | a number of sections containing raw data (@pxref{Sections}), | |
193 | @item | |
194 | a set of relocations (@pxref{Relocations}), and | |
195 | @item | |
196 | some symbol information (@pxref{Symbols}). | |
197 | @end itemize | |
198 | @noindent | |
199 | Also, BFDs opened for archives have the additional attribute of an index | |
200 | and contain subordinate BFDs. This approach is fine for a.out and coff, | |
201 | but loses efficiency when applied to formats such as S-records and | |
202 | IEEE-695. | |
203 | ||
204 | @node What BFD Version 2 Can Do, , How It Works, Overview | |
205 | @section What BFD Version 2 Can Do | |
206 | @include bfdsumm.texi | |
207 | ||
208 | @node BFD front end, BFD back ends, Overview, Top | |
53954f5e | 209 | @chapter BFD Front End |
252b5132 | 210 | @include bfdt.texi |
93509525 | 211 | @include bfdio.texi |
252b5132 RH |
212 | |
213 | @menu | |
214 | * Memory Usage:: | |
215 | * Initialization:: | |
216 | * Sections:: | |
217 | * Symbols:: | |
218 | * Archives:: | |
219 | * Formats:: | |
220 | * Relocations:: | |
221 | * Core Files:: | |
222 | * Targets:: | |
223 | * Architectures:: | |
224 | * Opening and Closing:: | |
225 | * Internal:: | |
226 | * File Caching:: | |
227 | * Linker Functions:: | |
228 | * Hash Tables:: | |
229 | @end menu | |
230 | ||
231 | @node Memory Usage, Initialization, BFD front end, BFD front end | |
53954f5e | 232 | @section Memory Usage |
252b5132 RH |
233 | BFD keeps all of its internal structures in obstacks. There is one obstack |
234 | per open BFD file, into which the current state is stored. When a BFD is | |
235 | closed, the obstack is deleted, and so everything which has been | |
236 | allocated by BFD for the closing file is thrown away. | |
237 | ||
238 | BFD does not free anything created by an application, but pointers into | |
239 | @code{bfd} structures become invalid on a @code{bfd_close}; for example, | |
240 | after a @code{bfd_close} the vector passed to | |
241 | @code{bfd_canonicalize_symtab} is still around, since it has been | |
242 | allocated by the application, but the data that it pointed to are | |
243 | lost. | |
244 | ||
245 | The general rule is to not close a BFD until all operations dependent | |
246 | upon data from the BFD have been completed, or all the data from within | |
247 | the file has been copied. To help with the management of memory, there | |
248 | is a function (@code{bfd_alloc_size}) which returns the number of bytes | |
249 | in obstacks associated with the supplied BFD. This could be used to | |
250 | select the greediest open BFD, close it to reclaim the memory, perform | |
251 | some operation and reopen the BFD again, to get a fresh copy of the data | |
252 | structures. | |
253 | ||
254 | @node Initialization, Sections, Memory Usage, BFD front end | |
255 | @include init.texi | |
256 | ||
257 | @node Sections, Symbols, Initialization, BFD front end | |
258 | @include section.texi | |
259 | ||
260 | @node Symbols, Archives, Sections, BFD front end | |
261 | @include syms.texi | |
262 | ||
263 | @node Archives, Formats, Symbols, BFD front end | |
264 | @include archive.texi | |
265 | ||
266 | @node Formats, Relocations, Archives, BFD front end | |
267 | @include format.texi | |
268 | ||
269 | @node Relocations, Core Files, Formats, BFD front end | |
270 | @include reloc.texi | |
271 | ||
272 | @node Core Files, Targets, Relocations, BFD front end | |
273 | @include core.texi | |
274 | ||
275 | @node Targets, Architectures, Core Files, BFD front end | |
276 | @include targets.texi | |
277 | ||
278 | @node Architectures, Opening and Closing, Targets, BFD front end | |
279 | @include archures.texi | |
280 | ||
281 | @node Opening and Closing, Internal, Architectures, BFD front end | |
282 | @include opncls.texi | |
283 | ||
284 | @node Internal, File Caching, Opening and Closing, BFD front end | |
285 | @include libbfd.texi | |
286 | ||
287 | @node File Caching, Linker Functions, Internal, BFD front end | |
288 | @include cache.texi | |
289 | ||
290 | @node Linker Functions, Hash Tables, File Caching, BFD front end | |
291 | @include linker.texi | |
292 | ||
293 | @node Hash Tables, , Linker Functions, BFD front end | |
294 | @include hash.texi | |
295 | ||
4a8e467a | 296 | @node BFD back ends, GNU Free Documentation License, BFD front end, Top |
252b5132 RH |
297 | @chapter BFD back ends |
298 | @menu | |
299 | * What to Put Where:: | |
300 | * aout :: a.out backends | |
301 | * coff :: coff backends | |
302 | * elf :: elf backends | |
3c3bdf30 | 303 | * mmo :: mmo backend |
252b5132 RH |
304 | @ignore |
305 | * oasys :: oasys backends | |
306 | * ieee :: ieee backend | |
307 | * srecord :: s-record backend | |
308 | @end ignore | |
309 | @end menu | |
310 | @node What to Put Where, aout, BFD back ends, BFD back ends | |
311 | All of BFD lives in one directory. | |
312 | ||
313 | @node aout, coff, What to Put Where, BFD back ends | |
314 | @include aoutx.texi | |
315 | ||
316 | @node coff, elf, aout, BFD back ends | |
317 | @include coffcode.texi | |
318 | ||
3c3bdf30 | 319 | @node elf, mmo, coff, BFD back ends |
252b5132 RH |
320 | @include elf.texi |
321 | @c Leave this out until the file has some actual contents... | |
322 | @c @include elfcode.texi | |
323 | ||
3c3bdf30 NC |
324 | @node mmo, , elf, BFD back ends |
325 | @include mmo.texi | |
326 | ||
4a8e467a | 327 | @node GNU Free Documentation License, Index, BFD back ends, Top |
53954f5e NC |
328 | @include fdl.texi |
329 | ||
330 | @node Index, , GNU Free Documentation License, Top | |
252b5132 RH |
331 | @unnumbered Index |
332 | @printindex cp | |
333 | ||
334 | @tex | |
335 | % I think something like @colophon should be in texinfo. In the | |
336 | % meantime: | |
337 | \long\def\colophon{\hbox to0pt{}\vfill | |
338 | \centerline{The body of this manual is set in} | |
339 | \centerline{\fontname\tenrm,} | |
340 | \centerline{with headings in {\bf\fontname\tenbf}} | |
341 | \centerline{and examples in {\tt\fontname\tentt}.} | |
342 | \centerline{{\it\fontname\tenit\/} and} | |
343 | \centerline{{\sl\fontname\tensl\/}} | |
344 | \centerline{are used for emphasis.}\vfill} | |
345 | \page\colophon | |
346 | % Blame: doc@cygnus.com, 28mar91. | |
347 | @end tex | |
348 | ||
349 | @contents | |
350 | @bye |