-\input texinfo
-@setfilename bfdinfo
-@c $Id$
-@synindex ky cp
+\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
+@c Free Software Foundation, Inc.
+@c
+@synindex fn cp
+
@ifinfo
+@format
+START-INFO-DIR-ENTRY
+* Bfd: (bfd). The Binary File Descriptor library.
+END-INFO-DIR-ENTRY
+@end format
+@end ifinfo
+
+@copying
This file documents the BFD library.
-Copyright (C) 1991 Free Software Foundation, Inc.
+Copyright @copyright{} 1991, 2000, 2001, 2003, 2006, 2007, 2008 Free Software Foundation, Inc.
-Permission is granted to make and distribute verbatim copies of
-this manual provided the copyright notice and this permission notice
-are preserved on all copies.
+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''.
-@ignore
-Permission is granted to process this file through Tex and print the
-results, provided the printed document carries copying permission
-notice identical to this one except for the removal of this paragraph
-(this paragraph not being relevant to the printed manual).
+(a) The FSF's Front-Cover Text is:
-@end ignore
-Permission is granted to copy and distribute modified versions of this
-manual under the conditions for verbatim copying, subject to the terms
-of the GNU General Public License, which includes the provision that the
-entire resulting derived work is distributed under the terms of a
-permission notice identical to this one.
-
-Permission is granted to copy and distribute translations of this manual
-into another language, under the above conditions for modified versions.
-@end ifinfo
+ 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
@title{libbfd}
@subtitle{The Binary File Descriptor Library}
@sp 1
-@subtitle First Edition---BFD version < 2.0
-@subtitle April 1991
+@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{\$Revision$} % For use in headers, footers too
+\xdef\manvers{1.5} % For use in headers, footers too
{\parskip=0pt
-\hfill Cygnus Support\par
-\hfill steve\@cygnus.com\par
+\hfill Free Software Foundation\par
+\hfill sac\@www.gnu.org\par
\hfill {\it BFD}, \manvers\par
\hfill \TeX{}info \texinfoversion\par
}
@end tex
@vskip 0pt plus 1filll
-Copyright @copyright{} 1991 Free Software Foundation, Inc.
+Copyright @copyright{} 1991, 2001, 2003, 2006, 2008 Free Software Foundation, Inc.
-Permission is granted to make and distribute verbatim copies of
-this manual provided the copyright notice and this permission notice
-are preserved on all copies.
+ 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''.
-Permission is granted to copy and distribute modified versions of this
-manual under the conditions for verbatim copying, subject to the terms
-of the GNU General Public License, which includes the provision that the
-entire resulting derived work is distributed under the terms of a
-permission notice identical to this one.
-
-Permission is granted to copy and distribute translations of this manual
-into another language, under the above conditions for modified versions.
@end titlepage
@end iftex
+@contents
@node Top, Overview, (dir), (dir)
@ifinfo
@menu
* Overview:: Overview of BFD
-* History:: History of BFD
-* Backends:: Backends
-* Porting:: Porting
-* Future:: Future
-* Index:: Index
-
-BFD body:
-* Memory usage::
-* Sections::
-* Symbols::
-* Archives::
-* Formats::
-* Relocations::
-* Core Files::
-* Targets::
-* Architecturs::
-* Opening and Closing::
-* Internal::
-* File Caching::
-
-BFD backends:
-* a.out backends::
-* coff backends::
+* 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, History, Top, Top
+@node Overview, BFD front end, Top, Top
@chapter Introduction
@cindex BFD
@cindex what is it?
-Simply put, BFD is a package which allows applications to use the
+BFD is a package which allows applications to use the
same routines to operate on object files whatever the object file
-format. A different object file format can be supported simply by
+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 many back ends.
+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.
+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
-@node History, How It Works, Overview,Top
+@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
-Cygnus was contracted to provide the required functionality.
+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
different object file formats: IEEE-695, Oasys, Srecords, a.out and 68k
coff.
-BFD was first implemented by Steve Chamberlain (steve@@cygnus.com),
-John Gilmore (gnu@@cygnus.com), K. Richard Pixley (rich@@cygnus.com) and
-David Wallace (gumby@@cygnus.com) at Cygnus Support in Palo Alto,
-California.
+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, History, Porting, Top
-@section How It Works
+@node How It Works, What BFD Version 2 Can Do, History, Overview
+@section How To Use BFD
-To use the library, include @code{bfd.h} and link with @code{libbfd.a}.
+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 sucessfully opens a target file (object, archive or
-whatever) a pointer to an internal structure is returned. This pointer
+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
-@code{include/bfd.h}. Our convention is to call this pointer a BFD, and
+@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
-@samp{bfd}_.
+with @samp{bfd_} to reduce namespace pollution.
-For example, this sequence would do what you would probably expect:
+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}.
-@lisp
-@cartouche
+@example
+@c @cartouche
#include "bfd.h"
-unsigned int number_of_sections(abfd)
+unsigned int number_of_sections (abfd)
bfd *abfd;
@{
- return bfd_count_sections(abfd);
+ return bfd_count_sections (abfd);
@}
-@end cartouche
-@end lisp
-
-The abstraction used within BFD is that an object file has a header,
-a number of sections containing raw data, a set of relocations, and some
-symbol information. 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.
-
-@section What BFD Version 1 Can Do
-As different information from the the object files is required,
-BFD reads from different sections of the file and processes them.
-For example a very common operation for the linker is processing symbol
-tables. Each BFD back end provides a routine for converting
-between the object file's representation of symbols and an internal
-canonical format. When the linker asks for the symbol table of an object
-file, it calls through the memory pointer to the relevant BFD
-back end routine which reads and converts the table into a canonical
-form. The linker then operates upon the canonical form. When the link is
-finished and the linker writes the output file's symbol table,
-another BFD back end routine is called which takes the newly
-created symbol table and converts it into the chosen output format.
-
-@node BFD information loss, Mechanism, BFD outline, BFD
-@subsection Information Loss
-@emph{Some information is lost due to the nature of the file format.} The output targets
-supported by BFD do not provide identical facilities, and
-information which may be described in one form has nowhere to go in
-another format. One example of this is alignment information in
-@code{b.out}. There is nowhere in an @code{a.out} format file to store
-alignment information on the contained data, so when a file is linked
-from @code{b.out} and an @code{a.out} image is produced, alignment
-information will not propagate to the output file. (The linker will
-still use the alignment information internally, so the link is performed
-correctly).
-
-Another example is COFF section names. COFF files may contain an
-unlimited number of sections, each one with a textual section name. If
-the target of the link is a format which does not have many sections (eg
-@code{a.out}) or has sections without names (eg the Oasys format) the
-link cannot be done simply. You can circumvent this problem by
-describing the desired input-to-output section mapping with the linker command
-language.
-
-@emph{Information can be lost during canonicalization.} The BFD
-internal canonical form of the external formats is not exhaustive; there
-are structures in input formats for which there is no direct
-representation internally. This means that the BFD back ends
-cannot maintain all possible data richness through the transformation
-between external to internal and back to external formats.
-
-This limitation is only a problem when an application reads one
-format and writes another. Each BFD back end is responsible for
-maintaining as much data as possible, and the internal BFD
-canonical form has structures which are opaque to the BFD core,
-and exported only to the back ends. When a file is read in one format,
-the canonical form is generated for BFD and the application. At the
-same time, the back end saves away any information which may otherwise
-be lost. If the data is then written back in the same format, the back
-end routine will be able to use the canonical form provided by the
-BFD core as well as the information it prepared earlier. Since
-there is a great deal of commonality between back ends, this mechanism
-is very useful. There is no information lost for this reason when
-linking or copying big endian COFF to little endian COFF, or @code{a.out} to
-@code{b.out}. When a mixture of formats is linked, the information is
-only lost from the files whose format differs from the destination.
-
-@node Mechanism, , BFD information loss, BFD
-@subsection Mechanism
-The greatest potential for loss of information is when there is least
-overlap between the information provided by the source format, that
-stored by the canonical format, and the information needed by the
-destination format. A brief description of the canonical form may help
-you appreciate what kinds of data you can count on preserving across
-conversions.
-@cindex BFD canonical format
-@cindex internal object-file format
-
-@table @emph
-@item files
-Information on target machine architecture, particular implementation
-and format type are stored on a per-file basis. Other information
-includes a demand pageable bit and a write protected bit. Note that
-information like Unix magic numbers is not stored here---only the magic
-numbers' meaning, so a @code{ZMAGIC} file would have both the demand
-pageable bit and the write protected text bit set. The byte order of
-the target is stored on a per-file basis, so that big- and little-endian
-object files may be linked with one another.
-@c FIXME: generalize above from "link"?
-
-@item sections
-Each section in the input file contains the name of the section, the
-original address in the object file, various flags, size and alignment
-information and pointers into other BFD data structures.
-
-@item symbols
-Each symbol contains a pointer to the object file which originally
-defined it, its name, its value, and various flag bits. When a
-BFD back end reads in a symbol table, the back end relocates all
-symbols to make them relative to the base of the section where they were
-defined. This ensures that each symbol points to its containing
-section. Each symbol also has a varying amount of hidden data to contain
-private data for the BFD back end. Since the symbol points to the
-original file, the private data format for that symbol is accessible.
-@code{gld} can operate on a collection of symbols of wildly different
-formats without problems.
-
-Normal global and simple local symbols are maintained on output, so an
-output file (no matter its format) will retain symbols pointing to
-functions and to global, static, and common variables. Some symbol
-information is not worth retaining; in @code{a.out} type information is
-stored in the symbol table as long symbol names. This information would
-be useless to most COFF debuggers; the linker has command line switches
-to allow users to throw it away.
-
-There is one word of type information within the symbol, so if the
-format supports symbol type information within symbols (for example COFF,
-IEEE, Oasys) and the type is simple enough to fit within one word
-(nearly everything but aggregates) the information will be preserved.
-
-@item relocation level
-Each canonical BFD relocation record contains a pointer to the symbol to
-relocate to, the offset of the data to relocate, the section the data
-is in and a pointer to a relocation type descriptor. Relocation is
-performed effectively by message passing through the relocation type
-descriptor and symbol pointer. It allows relocations to be performed
-on output data using a relocation method only available in one of the
-input formats. For instance, Oasys provides a byte relocation format.
-A relocation record requesting this relocation type would point
-indirectly to a routine to perform this, so the relocation may be
-performed on a byte being written to a COFF file, even though 68k COFF
-has no such relocation type.
-
-@item line numbers
-Object formats can contain, for debugging purposes, some form of mapping
-between symbols, source line numbers, and addresses in the output file.
-These addresses have to be relocated along with the symbol information.
-Each symbol with an associated list of line number records points to the
-first record of the list. The head of a line number list consists of a
-pointer to the symbol, which allows divination of the address of the
-function whose line number is being described. The rest of the list is
-made up of pairs: offsets into the section and line numbers. Any format
-which can simply derive this information can pass it successfully
-between formats (COFF, IEEE and Oasys).
-@end table
-
-@c FIXME: what is this line about? Do we want introductory remarks
-@c FIXME... on back ends? commented out for now.
-@c What is a backend
-@node BFD front end, BFD back end, Mechanism, Top
-@chapter BFD front end
-@include bfd.texi
-
-@node Memory Usage, Sections, bfd, Top
+@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 its internal structures in obstacks. There is one obstack
+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 libbfd for the closing file will be thrown away.
+allocated by BFD for the closing file is thrown away.
-BFD will not free anything created by an application, but pointers into
-@code{bfd} structures will be invalidated on a @code{bfd_close}; for example,
+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} will still be around, since it has been
-allocated by the application, but the data that it pointed to will be
+@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 not to close a BFD until all operations dependent
+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.
+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 Sections,Symbols ,Memory Usage, Top
+@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, To
+@node Symbols, Archives, Sections, BFD front end
@include syms.texi
-@node Archives, Formats, Symbols, Top
+@node Archives, Formats, Symbols, BFD front end
@include archive.texi
-@node Formats, Relocations, Archives, Top
+@node Formats, Relocations, Archives, BFD front end
@include format.texi
-@node Relocations, Core Files,Formats, Top
+@node Relocations, Core Files, Formats, BFD front end
@include reloc.texi
-@node Core Files, Targets, Relocations, Top
+@node Core Files, Targets, Relocations, BFD front end
@include core.texi
-@node Targets, Architectures, Core Files, Top
+@node Targets, Architectures, Core Files, BFD front end
@include targets.texi
-@node Architectures, Opening and Closing, Targets, Top
+@node Architectures, Opening and Closing, Targets, BFD front end
@include archures.texi
-@node Opening and Closing, Internal, Architectures, Top
+@node Opening and Closing, Internal, Architectures, BFD front end
@include opncls.texi
-@node Internal, File Caching, Opening and Closing, Top
+@node Internal, File Caching, Opening and Closing, BFD front end
@include libbfd.texi
-@node File Caching, Top, Internal, Top
+@node File Caching, Linker Functions, Internal, BFD front end
@include cache.texi
-@chapter BFD back end
-@node BFD back end, ,BFD front end, Top
+@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
-* a.out backends::
-* coff backends::
-* oasys backend::
-* ieee backend::
-* srecord backend::
+* 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 backends, BFD back end, BFD back end
+@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 backends, coff backends, What to Put Where, BFD back end
+@node aout, coff, What to Put Where, BFD back ends
@include aoutx.texi
-@node coff backends, oasys backends, aout backends, BFD back end
+@node coff, elf, aout, BFD back ends
@include coffcode.texi
-@node Index, , BFD, Top
-@unnumbered Function Index
-@printindex fn
-@unnumbered Index
+@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
\centerline{{\sl\fontname\tensl\/}}
\centerline{are used for emphasis.}\vfill}
\page\colophon
-% Blame: pesch@cygnus.com, 28mar91.
+% Blame: doc@cygnus.com, 28mar91.
@end tex
-
-@contents
@bye
-
-
projects / external / binutils.git / blobdiff