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