| \input texinfo.tex |
| @setfilename bfd.info |
| @c Copyright 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1997, 2000, |
| @c 2001, 2002, 2003, 2006, 2007, 2008, 2009, 2013 |
| @c Free Software Foundation, Inc. |
| @c |
| @synindex fn cp |
| |
| @ifnottex |
| @dircategory Software development |
| @direntry |
| * Bfd: (bfd). The Binary File Descriptor library. |
| @end direntry |
| @end ifnottex |
| |
| @copying |
| This file documents the BFD library. |
| |
| Copyright @copyright{} 1991, 2000, 2001, 2003, 2006, 2007, 2008, 2013 |
| Free Software Foundation, Inc. |
| |
| Permission is granted to copy, distribute and/or modify this document |
| under the terms of the GNU Free Documentation License, Version 1.3 or |
| any later version published by the Free Software Foundation; with the |
| Invariant Sections being ``GNU General Public License'' and ``Funding |
| Free Software'', the Front-Cover texts being (a) (see below), and with |
| the Back-Cover Texts being (b) (see below). A copy of the license is |
| included in the section entitled ``GNU Free Documentation License''. |
| |
| (a) The FSF's Front-Cover Text is: |
| |
| A GNU Manual |
| |
| (b) The FSF's Back-Cover Text is: |
| |
| You have freedom to copy and modify this GNU Manual, like GNU |
| software. Copies published by the Free Software Foundation raise |
| funds for GNU development. |
| @end copying |
| @iftex |
| @c@finalout |
| @setchapternewpage on |
| @c@setchapternewpage odd |
| @settitle LIB BFD, the Binary File Descriptor Library |
| @titlepage |
| @title{libbfd} |
| @subtitle{The Binary File Descriptor Library} |
| @sp 1 |
| @subtitle First Edition---BFD version < 3.0 % Since no product is stable before version 3.0 :-) |
| @subtitle Original Document Created: April 1991 |
| @author {Steve Chamberlain} |
| @author {Cygnus Support} |
| @page |
| |
| @tex |
| \def\$#1${{#1}} % Kluge: collect RCS revision info without $...$ |
| \xdef\manvers{1.5} % For use in headers, footers too |
| {\parskip=0pt |
| \hfill Free Software Foundation\par |
| \hfill sac\@www.gnu.org\par |
| \hfill {\it BFD}, \manvers\par |
| \hfill \TeX{}info \texinfoversion\par |
| } |
| \global\parindent=0pt % Steve likes it this way |
| @end tex |
| |
| @vskip 0pt plus 1filll |
| Copyright @copyright{} 1991, 2001, 2003, 2006, 2008, 2013 |
| Free Software Foundation, Inc. |
| |
| Permission is granted to copy, distribute and/or modify this document |
| under the terms of the GNU Free Documentation License, Version 1.3 |
| or any later version published by the Free Software Foundation; |
| with no Invariant Sections, with no Front-Cover Texts, and with no |
| Back-Cover Texts. A copy of the license is included in the |
| section entitled ``GNU Free Documentation License''. |
| |
| @end titlepage |
| @end iftex |
| @contents |
| |
| @node Top, Overview, (dir), (dir) |
| @ifinfo |
| This file documents the binary file descriptor library libbfd. |
| @end ifinfo |
| |
| @menu |
| * Overview:: Overview of BFD |
| * BFD front end:: BFD front end |
| * BFD back ends:: BFD back ends |
| * GNU Free Documentation License:: GNU Free Documentation License |
| * BFD Index:: BFD Index |
| @end menu |
| |
| @node Overview, BFD front end, Top, Top |
| @chapter Introduction |
| @cindex BFD |
| @cindex what is it? |
| BFD is a package which allows applications to use the |
| same routines to operate on object files whatever the object file |
| format. A new object file format can be supported simply by |
| creating a new BFD back end and adding it to the library. |
| |
| BFD is split into two parts: the front end, and the back ends (one for |
| each object file format). |
| @itemize @bullet |
| @item The front end of BFD provides the interface to the user. It manages |
| memory and various canonical data structures. The front end also |
| decides which back end to use and when to call back end routines. |
| @item The back ends provide BFD its view of the real world. Each back |
| end provides a set of calls which the BFD front end can use to maintain |
| its canonical form. The back ends also may keep around information for |
| their own use, for greater efficiency. |
| @end itemize |
| @menu |
| * History:: History |
| * How It Works:: How It Works |
| * What BFD Version 2 Can Do:: What BFD Version 2 Can Do |
| @end menu |
| |
| @node History, How It Works, Overview, Overview |
| @section History |
| |
| One spur behind BFD was the desire, on the part of the GNU 960 team at |
| Intel Oregon, for interoperability of applications on their COFF and |
| b.out file formats. Cygnus was providing GNU support for the team, and |
| was contracted to provide the required functionality. |
| |
| The name came from a conversation David Wallace was having with Richard |
| Stallman about the library: RMS said that it would be quite hard---David |
| said ``BFD''. Stallman was right, but the name stuck. |
| |
| At the same time, Ready Systems wanted much the same thing, but for |
| different object file formats: IEEE-695, Oasys, Srecords, a.out and 68k |
| coff. |
| |
| BFD was first implemented by members of Cygnus Support; Steve |
| Chamberlain (@code{sac@@cygnus.com}), John Gilmore |
| (@code{gnu@@cygnus.com}), K. Richard Pixley (@code{rich@@cygnus.com}) |
| and David Henkel-Wallace (@code{gumby@@cygnus.com}). |
| |
| |
| |
| @node How It Works, What BFD Version 2 Can Do, History, Overview |
| @section How To Use BFD |
| |
| To use the library, include @file{bfd.h} and link with @file{libbfd.a}. |
| |
| BFD provides a common interface to the parts of an object file |
| for a calling application. |
| |
| When an application successfully opens a target file (object, archive, or |
| whatever), a pointer to an internal structure is returned. This pointer |
| points to a structure called @code{bfd}, described in |
| @file{bfd.h}. Our convention is to call this pointer a BFD, and |
| instances of it within code @code{abfd}. All operations on |
| the target object file are applied as methods to the BFD. The mapping is |
| defined within @code{bfd.h} in a set of macros, all beginning |
| with @samp{bfd_} to reduce namespace pollution. |
| |
| For example, this sequence does what you would probably expect: |
| return the number of sections in an object file attached to a BFD |
| @code{abfd}. |
| |
| @example |
| @c @cartouche |
| #include "bfd.h" |
| |
| unsigned int number_of_sections (abfd) |
| bfd *abfd; |
| @{ |
| return bfd_count_sections (abfd); |
| @} |
| @c @end cartouche |
| @end example |
| |
| The abstraction used within BFD is that an object file has: |
| |
| @itemize @bullet |
| @item |
| a header, |
| @item |
| a number of sections containing raw data (@pxref{Sections}), |
| @item |
| a set of relocations (@pxref{Relocations}), and |
| @item |
| some symbol information (@pxref{Symbols}). |
| @end itemize |
| @noindent |
| Also, BFDs opened for archives have the additional attribute of an index |
| and contain subordinate BFDs. This approach is fine for a.out and coff, |
| but loses efficiency when applied to formats such as S-records and |
| IEEE-695. |
| |
| @node What BFD Version 2 Can Do, , How It Works, Overview |
| @section What BFD Version 2 Can Do |
| @include bfdsumm.texi |
| |
| @node BFD front end, BFD back ends, Overview, Top |
| @chapter BFD Front End |
| @include bfdt.texi |
| @include bfdio.texi |
| |
| @menu |
| * Memory Usage:: |
| * Initialization:: |
| * Sections:: |
| * Symbols:: |
| * Archives:: |
| * Formats:: |
| * Relocations:: |
| * Core Files:: |
| * Targets:: |
| * Architectures:: |
| * Opening and Closing:: |
| * Internal:: |
| * File Caching:: |
| * Linker Functions:: |
| * Hash Tables:: |
| @end menu |
| |
| @node Memory Usage, Initialization, BFD front end, BFD front end |
| @section Memory Usage |
| BFD keeps all of its internal structures in obstacks. There is one obstack |
| per open BFD file, into which the current state is stored. When a BFD is |
| closed, the obstack is deleted, and so everything which has been |
| allocated by BFD for the closing file is thrown away. |
| |
| BFD does not free anything created by an application, but pointers into |
| @code{bfd} structures become invalid on a @code{bfd_close}; for example, |
| after a @code{bfd_close} the vector passed to |
| @code{bfd_canonicalize_symtab} is still around, since it has been |
| allocated by the application, but the data that it pointed to are |
| lost. |
| |
| The general rule is to not close a BFD until all operations dependent |
| upon data from the BFD have been completed, or all the data from within |
| the file has been copied. To help with the management of memory, there |
| is a function (@code{bfd_alloc_size}) which returns the number of bytes |
| in obstacks associated with the supplied BFD. This could be used to |
| select the greediest open BFD, close it to reclaim the memory, perform |
| some operation and reopen the BFD again, to get a fresh copy of the data |
| structures. |
| |
| @node Initialization, Sections, Memory Usage, BFD front end |
| @include init.texi |
| |
| @node Sections, Symbols, Initialization, BFD front end |
| @include section.texi |
| |
| @node Symbols, Archives, Sections, BFD front end |
| @include syms.texi |
| |
| @node Archives, Formats, Symbols, BFD front end |
| @include archive.texi |
| |
| @node Formats, Relocations, Archives, BFD front end |
| @include format.texi |
| |
| @node Relocations, Core Files, Formats, BFD front end |
| @include reloc.texi |
| |
| @node Core Files, Targets, Relocations, BFD front end |
| @include core.texi |
| |
| @node Targets, Architectures, Core Files, BFD front end |
| @include targets.texi |
| |
| @node Architectures, Opening and Closing, Targets, BFD front end |
| @include archures.texi |
| |
| @node Opening and Closing, Internal, Architectures, BFD front end |
| @include opncls.texi |
| |
| @node Internal, File Caching, Opening and Closing, BFD front end |
| @include libbfd.texi |
| |
| @node File Caching, Linker Functions, Internal, BFD front end |
| @include cache.texi |
| |
| @node Linker Functions, Hash Tables, File Caching, BFD front end |
| @include linker.texi |
| |
| @node Hash Tables, , Linker Functions, BFD front end |
| @include hash.texi |
| |
| @node BFD back ends, GNU Free Documentation License, BFD front end, Top |
| @chapter BFD back ends |
| @menu |
| * What to Put Where:: |
| * aout :: a.out backends |
| * coff :: coff backends |
| * elf :: elf backends |
| * mmo :: mmo backend |
| @ignore |
| * oasys :: oasys backends |
| * ieee :: ieee backend |
| * srecord :: s-record backend |
| @end ignore |
| @end menu |
| @node What to Put Where, aout, BFD back ends, BFD back ends |
| @section What to Put Where |
| All of BFD lives in one directory. |
| |
| @node aout, coff, What to Put Where, BFD back ends |
| @include aoutx.texi |
| |
| @node coff, elf, aout, BFD back ends |
| @include coffcode.texi |
| |
| @node elf, mmo, coff, BFD back ends |
| @include elf.texi |
| @c Leave this out until the file has some actual contents... |
| @c @include elfcode.texi |
| |
| @node mmo, , elf, BFD back ends |
| @include mmo.texi |
| |
| @node GNU Free Documentation License, BFD Index, BFD back ends, Top |
| @include fdl.texi |
| |
| @node BFD Index, , GNU Free Documentation License, Top |
| @unnumbered BFD Index |
| @printindex cp |
| |
| @tex |
| % I think something like @@colophon should be in texinfo. In the |
| % meantime: |
| \long\def\colophon{\hbox to0pt{}\vfill |
| \centerline{The body of this manual is set in} |
| \centerline{\fontname\tenrm,} |
| \centerline{with headings in {\bf\fontname\tenbf}} |
| \centerline{and examples in {\tt\fontname\tentt}.} |
| \centerline{{\it\fontname\tenit\/} and} |
| \centerline{{\sl\fontname\tensl\/}} |
| \centerline{are used for emphasis.}\vfill} |
| \page\colophon |
| % Blame: doc@@cygnus.com, 28mar91. |
| @end tex |
| |
| @bye |
