-\input texinfo
+\input texinfo @c -*- texinfo -*-
@setfilename gdbint.info
-@c $Id$
-
-@ifinfo
-@format
-START-INFO-DIR-ENTRY
+@include gdb-cfg.texi
+@dircategory Programming & development tools.
+@direntry
* Gdb-Internals: (gdbint). The GNU debugger's internals.
-END-INFO-DIR-ENTRY
-@end format
-@end ifinfo
+@end direntry
@ifinfo
-This file documents the internals of the GNU debugger GDB.
-
-Copyright 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
-Contributed by Cygnus Support. Written by John Gilmore.
-
-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.
-
-@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).
-
-@end ignore
-Permission is granted to copy or distribute modified versions of this
-manual under the terms of the GPL (for which purpose this text may be
-regarded as a program in the language TeX).
+This file documents the internals of the GNU debugger @value{GDBN}.
+Copyright 1990,1991,1992,1993,1994,1996,1998,1999,2000,2001
+ Free Software Foundation, Inc.
+Contributed by Cygnus Solutions. Written by John Gilmore.
+Second Edition by Stan Shebs.
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.1 or
+any later version published by the Free Software Foundation; with the
+Invariant Sections being ``Algorithms'' and ``Porting GDB'', with the
+Front-Cover texts being ``A GNU Manual,'' and with the Back-Cover
+Texts as in (a) below.
+
+(a) 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 ifinfo
@setchapternewpage off
-@settitle GDB Internals
+@settitle @value{GDBN} Internals
+
+@syncodeindex fn cp
+@syncodeindex vr cp
+
@titlepage
-@title{Working in GDB}
+@title @value{GDBN} Internals
@subtitle{A guide to the internals of the GNU debugger}
@author John Gilmore
-@author Cygnus Support
+@author Cygnus Solutions
+@author Second Edition:
+@author Stan Shebs
+@author Cygnus Solutions
@page
@tex
\def\$#1${{#1}} % Kluge: collect RCS revision info without $...$
\xdef\manvers{\$Revision$} % For use in headers, footers too
{\parskip=0pt
-\hfill Cygnus Support\par
+\hfill Cygnus Solutions\par
\hfill \manvers\par
\hfill \TeX{}info \texinfoversion\par
}
@end tex
@vskip 0pt plus 1filll
-Copyright @copyright{} 1990, 1991, 1992, 1993 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.
-
+Copyright @copyright{} 1990,1991,1992,1993,1994,1996,1998,1999,2000,2001
+ 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 1.1 or
+any later version published by the Free Software Foundation; with the
+Invariant Sections being ``Algorithms'' and ``Porting GDB'', with the
+Front-Cover texts being ``A GNU Manual,'' and with the Back-Cover
+Texts as in (a) below.
+
+(a) 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 titlepage
+@c TeX can handle the contents at the start but makeinfo 3.12 can not
+@iftex
+@contents
+@end iftex
+
@node Top
-@top
-@c IMHO much information should go into *comments* as you discover it
-@c or design changes to GDB. It's more likely to get noticed and
-@c easier to maintain there. -kingdon
-This documents the internals of the GNU debugger, GDB. It is a
-collection of miscellaneous information with little form at this point.
-Mostly, it is a repository into which you can put information about
-GDB as you discover it (or as you design changes to GDB).
+@c Perhaps this should be the title of the document (but only for info,
+@c not for TeX). Existing GNU manuals seem inconsistent on this point.
+@top Scope of this Document
+
+This document documents the internals of the GNU debugger, @value{GDBN}. It
+includes description of @value{GDBN}'s key algorithms and operations, as well
+as the mechanisms that adapt @value{GDBN} to specific hosts and targets.
@menu
-* README:: The README File
-* Getting Started:: Getting started working on GDB
-* Debugging GDB:: Debugging GDB with itself
-* New Architectures:: Defining a New Host or Target Architecture
-* Config:: Adding a New Configuration
-* Host:: Adding a New Host
-* Native:: Adding a New Native Configuration
-* Target:: Adding a New Target
-* Languages:: Defining New Source Languages
-* Releases:: Configuring GDB for Release
-* Partial Symbol Tables:: How GDB reads symbols quickly at startup
-* Types:: How GDB keeps track of types
-* BFD support for GDB:: How BFD and GDB interface
-* Symbol Reading:: Defining New Symbol Readers
-* Cleanups:: Cleanups
-* Wrapping:: Wrapping Output Lines
-* Frames:: Keeping track of function calls
-* Remote Stubs:: Code that runs in targets and talks to GDB
-* Longjmp Support:: Stepping through longjmp's in the target
-* Coding Style:: Strunk and White for GDB maintainers
-* Clean Design:: Frank Lloyd Wright for GDB maintainers
-* Submitting Patches:: How to get your changes into GDB releases
-* Host Conditionals:: What features exist in the host
-* Target Conditionals:: What features exist in the target
-* Native Conditionals:: Conditionals for when host and target are same
-* Obsolete Conditionals:: Conditionals that don't exist any more
-* XCOFF:: The Object file format used on IBM's RS/6000
+* Requirements::
+* Overall Structure::
+* Algorithms::
+* User Interface::
+* libgdb::
+* Symbol Handling::
+* Language Support::
+* Host Definition::
+* Target Architecture Definition::
+* Target Vector Definition::
+* Native Debugging::
+* Support Libraries::
+* Coding::
+* Porting GDB::
+* Testsuite::
+* Hints::
+* Index::
@end menu
-@node README
-@chapter The @file{README} File
+@node Requirements
-Check the @file{README} file, it often has useful information that does not
-appear anywhere else in the directory.
+@chapter Requirements
+@cindex requirements for @value{GDBN}
-@node Getting Started
-@chapter Getting Started Working on GDB
+Before diving into the internals, you should understand the formal
+requirements and other expectations for @value{GDBN}. Although some
+of these may seem obvious, there have been proposals for @value{GDBN}
+that have run counter to these requirements.
-GDB is a large and complicated program, and if you first starting to
-work on it, it can be hard to know where to start. Fortunately, if you
-know how to go about it, there are ways to figure out what is going on:
+First of all, @value{GDBN} is a debugger. It's not designed to be a
+front panel for embedded systems. It's not a text editor. It's not a
+shell. It's not a programming environment.
-@table @bullet
-@item
-This manual, the GDB Internals manual, has information which applies
-generally to many parts of GDB.
+@value{GDBN} is an interactive tool. Although a batch mode is
+available, @value{GDBN}'s primary role is to interact with a human
+programmer.
-@item
-Information about particular functions or data structures are located in
-comments with those functions or data structures. If you run across a
-function or a global variable which does not have a comment correctly
-explaining what is does, this can be thought of as a bug in GDB; feel
-free to submit a bug report, with a suggested comment if you can figure
-out what the comment should say (@pxref{Submitting Patches}). If you
-find a comment which is actually wrong, be especially sure to report that.
+@value{GDBN} should be responsive to the user. A programmer hot on
+the trail of a nasty bug, and operating under a looming deadline, is
+going to be very impatient of everything, including the response time
+to debugger commands.
-Comments explaining the function of macros defined in host, target, or
-native dependent files can be in several places. Sometimes they are
-repeated every place the macro is defined. Sometimes they are where the
-macro is used. Sometimes there is a header file which supplies a
-default definition of the macro, and the comment is there. This manual
-also has a list of macros (@pxref{Host Conditionals}, @pxref{Target
-Conditionals}, @pxref{Native Conditionals}, and @pxref{Obsolete
-Conditionals}) with some documentation.
+@value{GDBN} should be relatively permissive, such as for expressions.
+While the compiler should be picky (or have the option to be made
+picky), since source code lives for a long time usually, the
+programmer doing debugging shouldn't be spending time figuring out to
+mollify the debugger.
-@item
-Start with the header files. Once you some idea of how GDB's internal
-symbol tables are stored (see @file{symtab.h}, @file{gdbtypes.h}), you
-will find it much easier to understand the code which uses and creates
-those symbol tables.
+@value{GDBN} will be called upon to deal with really large programs.
+Executable sizes of 50 to 100 megabytes occur regularly, and we've
+heard reports of programs approaching 1 gigabyte in size.
-@item
-You may wish to process the information you are getting somehow, to
-enhance your understanding of it. Summarize it, translate it to another
-language, add some (perhaps trivial or non-useful) feature to GDB, use
-the code to predict what a test case would do and write the test case
-and verify your prediction, etc. If you are reading code and your eyes
-are starting to glaze over, this is a sign you need to use a more active
-approach.
+@value{GDBN} should be able to run everywhere. No other debugger is
+available for even half as many configurations as @value{GDBN}
+supports.
-@item
-Once you have a part of GDB to start with, you can find more
-specifically the part you are looking for by stepping through each
-function with the @code{next} command. Do not use @code{step} or you
-will quickly get distracted; when the function you are stepping through
-calls another function try only to get a big-picture understanding
-(perhaps using the comment at the beginning of the function being
-called) of what it does. This way you can identify which of the
-functions being called by the function you are stepping through is the
-one which you are interested in. You may need to examine the data
-structures generated at each stage, with reference to the comments in
-the header files explaining what the data structures are supposed to
-look like.
-Of course, this same technique can be used if you are just reading the
-code, rather than actually stepping through it. The same general
-principle applies---when the code you are looking at calls something
-else, just try to understand generally what the code being called does,
-rather than worrying about all its details.
+@node Overall Structure
-@item
-A good place to start when tracking down some particular area is with a
-command which invokes that feature. Suppose you want to know how
-single-stepping works. As a GDB user, you know that the @code{step}
-command invokes single-stepping. The command is invoked via command
-tables (see @file{command.h}); by convention the function which actually
-performs the command is formed by taking the name of the command and
-adding @samp{_command}, or in the case of an @code{info} subcommand,
-@samp{_info}. For example, the @code{step} command invokes the
-@code{step_command} function and the @code{info display} command invokes
-@code{display_info}. When this convention is not followed, you might
-have to use @code{grep} or @kbd{M-x tags-search} in emacs, or run GDB on
-itself and set a breakpoint in @code{execute_command}.
+@chapter Overall Structure
-@item
-If all of the above fail, it may be appropriate to ask for information
-on @code{bug-gdb}. But @emph{never} post a generic question like ``I was
-wondering if anyone could give me some tips about understanding
-GDB''---if we had some magic secret we would put it in this manual.
-Suggestions for improving the manual are always welcome, of course.
-@end table
+@value{GDBN} consists of three major subsystems: user interface,
+symbol handling (the @dfn{symbol side}), and target system handling (the
+@dfn{target side}).
-Good luck!
+The user interface consists of several actual interfaces, plus
+supporting code.
-@node Debugging GDB
-@chapter Debugging GDB with itself
-If gdb is limping on your machine, this is the preferred way to get it
-fully functional. Be warned that in some ancient Unix systems, like
-Ultrix 4.0, a program can't be running in one process while it is being
-debugged in another. Rather than typing the command @code{@w{./gdb
-./gdb}}, which works on Suns and such, you can copy @file{gdb} to
-@file{gdb2} and then type @code{@w{./gdb ./gdb2}}.
+The symbol side consists of object file readers, debugging info
+interpreters, symbol table management, source language expression
+parsing, type and value printing.
-When you run gdb in the gdb source directory, it will read a
-@file{.gdbinit} file that sets up some simple things to make debugging
-gdb easier. The @code{info} command, when executed without a subcommand
-in a gdb being debugged by gdb, will pop you back up to the top level
-gdb. See @file{.gdbinit} for details.
+The target side consists of execution control, stack frame analysis, and
+physical target manipulation.
-If you use emacs, you will probably want to do a @code{make TAGS} after
-you configure your distribution; this will put the machine dependent
-routines for your local machine where they will be accessed first by
-@kbd{M-.}
+The target side/symbol side division is not formal, and there are a
+number of exceptions. For instance, core file support involves symbolic
+elements (the basic core file reader is in BFD) and target elements (it
+supplies the contents of memory and the values of registers). Instead,
+this division is useful for understanding how the minor subsystems
+should fit together.
-Also, make sure that you've either compiled gdb with your local cc, or
-have run @code{fixincludes} if you are compiling with gcc.
+@section The Symbol Side
+
+The symbolic side of @value{GDBN} can be thought of as ``everything
+you can do in @value{GDBN} without having a live program running''.
+For instance, you can look at the types of variables, and evaluate
+many kinds of expressions.
+
+@section The Target Side
-@node New Architectures
-@chapter Defining a New Host or Target Architecture
+The target side of @value{GDBN} is the ``bits and bytes manipulator''.
+Although it may make reference to symbolic info here and there, most
+of the target side will run with only a stripped executable
+available---or even no executable at all, in remote debugging cases.
-When building support for a new host and/or target, much of the work you
-need to do is handled by specifying configuration files;
-@pxref{Config,,Adding a New Configuration}. Further work can be
-divided into ``host-dependent'' (@pxref{Host,,Adding a New Host}) and
-``target-dependent'' (@pxref{Target,,Adding a New Target}). The
-following discussion is meant to explain the difference between hosts
-and targets.
+Operations such as disassembly, stack frame crawls, and register
+display, are able to work with no symbolic info at all. In some cases,
+such as disassembly, @value{GDBN} will use symbolic info to present addresses
+relative to symbols rather than as raw numbers, but it will work either
+way.
-@heading What is considered ``host-dependent'' versus ``target-dependent''?
+@section Configurations
-@dfn{Host} refers to attributes of the system where GDB runs.
+@cindex host
+@cindex target
+@dfn{Host} refers to attributes of the system where @value{GDBN} runs.
@dfn{Target} refers to the system where the program being debugged
-executes. In most cases they are the same machine, in which case
-a third type of @dfn{Native} attributes come into play.
+executes. In most cases they are the same machine, in which case a
+third type of @dfn{Native} attributes come into play.
Defines and include files needed to build on the host are host support.
Examples are tty support, system defined types, host byte order, host
is native dependent. One example is Unix child process support; if the
host and target are not the same, doing a fork to start the target
process is a bad idea. The various macros needed for finding the
-registers in the @code{upage}, running @code{ptrace}, and such are all in the
-native-dependent files.
+registers in the @code{upage}, running @code{ptrace}, and such are all
+in the native-dependent files.
-Another example of native-dependent code is support for features
-that are really part of the target environment, but which require
-@code{#include} files that are only available on the host system.
-Core file handling and @code{setjmp} handling are two common cases.
+Another example of native-dependent code is support for features that
+are really part of the target environment, but which require
+@code{#include} files that are only available on the host system. Core
+file handling and @code{setjmp} handling are two common cases.
-When you want to make GDB work ``native'' on a particular
-machine, you have to include all three kinds of information.
+When you want to make @value{GDBN} work ``native'' on a particular machine, you
+have to include all three kinds of information.
-The dependent information in GDB is organized into files by naming
-conventions.
-Host-Dependent Files
-@table @file
-@item config/*/*.mh
-Sets Makefile parameters
-@item config/*/xm-*.h
-Global #include's and #define's and definitions
-@item *-xdep.c
-Global variables and functions
-@end table
-
-Native-Dependent Files
-@table @file
-@item config/*/*.mh
-Sets Makefile parameters (for @emph{both} host and native)
-@item config/*/nm-*.h
-#include's and #define's and definitions. This file
-is only included by the small number of modules that need it,
-so beware of doing feature-test #define's from its macros.
-@item *-nat.c
-global variables and functions
-@end table
+@node Algorithms
-Target-Dependent Files
-@table @file
-@item config/*/*.mt
-Sets Makefile parameters
-@item config/*/tm-*.h
-Global #include's and #define's and definitions
-@item *-tdep.c
-Global variables and functions
-@end table
+@chapter Algorithms
+@cindex algorithms
-At this writing, most supported hosts have had their host and native
-dependencies sorted out properly. There are a few stragglers, which
-can be recognized by the absence of NATDEPFILES lines in their
-@file{config/*/*.mh}.
+@value{GDBN} uses a number of debugging-specific algorithms. They are
+often not very complicated, but get lost in the thicket of special
+cases and real-world issues. This chapter describes the basic
+algorithms and mentions some of the specific target definitions that
+they use.
-@node Config
-@chapter Adding a New Configuration
+@section Frames
-Most of the work in making GDB compile on a new machine is in specifying
-the configuration of the machine. This is done in a dizzying variety of
-header files and configuration scripts, which we hope to make more
-sensible soon. Let's say your new host is called an @var{xxx} (e.g.
-@samp{sun4}), and its full three-part configuration name is
-@code{@var{xarch}-@var{xvend}-@var{xos}} (e.g. @samp{sparc-sun-sunos4}). In
-particular:
+@cindex frame
+@cindex call stack frame
+A frame is a construct that @value{GDBN} uses to keep track of calling
+and called functions.
-In the top level directory, edit @file{config.sub} and add @var{xarch},
-@var{xvend}, and @var{xos} to the lists of supported architectures,
-vendors, and operating systems near the bottom of the file. Also, add
-@var{xxx} as an alias that maps to
-@code{@var{xarch}-@var{xvend}-@var{xos}}. You can test your changes by
-running
+@findex create_new_frame
+@vindex FRAME_FP
+@code{FRAME_FP} in the machine description has no meaning to the
+machine-independent part of @value{GDBN}, except that it is used when
+setting up a new frame from scratch, as follows:
@example
-./config.sub @var{xxx}
-@end example
-@noindent
-and
-@example
-./config.sub @code{@var{xarch}-@var{xvend}-@var{xos}}
+ create_new_frame (read_register (FP_REGNUM), read_pc ()));
@end example
-@noindent
-which should both respond with @code{@var{xarch}-@var{xvend}-@var{xos}}
-and no error messages.
-
-Now, go to the @file{bfd} directory and
-create a new file @file{bfd/hosts/h-@var{xxx}.h}. Examine the
-other @file{h-*.h} files as templates, and create one that brings in the
-right include files for your system, and defines any host-specific
-macros needed by BFD, the Binutils, GNU LD, or the Opcodes directories.
-(They all share the bfd @file{hosts} directory and the @file{configure.host}
-file.)
-
-Then edit @file{bfd/configure.host}. Add a line to recognize your
-@code{@var{xarch}-@var{xvend}-@var{xos}} configuration, and set
-@code{my_host} to @var{xxx} when you recognize it. This will cause your
-file @file{h-@var{xxx}.h} to be linked to @file{sysdep.h} at configuration
-time. When creating the line that recognizes your configuration,
-only match the fields that you really need to match; e.g. don't match
-match the architecture or manufacturer if the OS is sufficient
-to distinguish the configuration that your @file{h-@var{xxx}.h} file supports.
-Don't match the manufacturer name unless you really need to.
-This should make future ports easier.
-
-Also, if this host requires any changes to the Makefile, create a file
-@file{bfd/config/@var{xxx}.mh}, which includes the required lines.
-
-It's possible that the @file{libiberty} and @file{readline} directories
-won't need any changes for your configuration, but if they do, you can
-change the @file{configure.in} file there to recognize your system and
-map to an @file{mh-@var{xxx}} file. Then add @file{mh-@var{xxx}}
-to the @file{config/} subdirectory, to set any makefile variables you
-need. The only current options in there are things like @samp{-DSYSV}.
-(This @file{mh-@var{xxx}} naming convention differs from elsewhere
-in GDB, by historical accident. It should be cleaned up so that all
-such files are called @file{@var{xxx}.mh}.)
-
-Aha! Now to configure GDB itself! Edit
-@file{gdb/configure.in} to recognize your system and set @code{gdb_host}
-to @var{xxx}, and (unless your desired target is already available) also
-set @code{gdb_target} to something appropriate (for instance,
-@var{xxx}). To handle new hosts, modify the segment after the comment
-@samp{# per-host}; to handle new targets, modify after @samp{#
-per-target}.
-@c Would it be simpler to just use different per-host and per-target
-@c *scripts*, and call them from {configure} ?
-
-Finally, you'll need to specify and define GDB's host-, native-, and
-target-dependent @file{.h} and @file{.c} files used for your
-configuration; the next two chapters discuss those.
-
-@node Host
-@chapter Adding a New Host
-
-Once you have specified a new configuration for your host
-(@pxref{Config,,Adding a New Configuration}), there are three remaining
-pieces to making GDB work on a new machine. First, you have to make it
-host on the new machine (compile there, handle that machine's terminals
-properly, etc). If you will be cross-debugging to some other kind of
-system that's already supported, you are done.
+@cindex frame pointer register
+Other than that, all the meaning imparted to @code{FP_REGNUM} is
+imparted by the machine-dependent code. So, @code{FP_REGNUM} can have
+any value that is convenient for the code that creates new frames.
+(@code{create_new_frame} calls @code{INIT_EXTRA_FRAME_INFO} if it is
+defined; that is where you should use the @code{FP_REGNUM} value, if
+your frames are nonstandard.)
+
+@cindex frame chain
+Given a @value{GDBN} frame, define @code{FRAME_CHAIN} to determine the
+address of the calling function's frame. This will be used to create
+a new @value{GDBN} frame struct, and then @code{INIT_EXTRA_FRAME_INFO}
+and @code{INIT_FRAME_PC} will be called for the new frame.
+
+@section Breakpoint Handling
+
+@cindex breakpoints
+In general, a breakpoint is a user-designated location in the program
+where the user wants to regain control if program execution ever reaches
+that location.
+
+There are two main ways to implement breakpoints; either as ``hardware''
+breakpoints or as ``software'' breakpoints.
+
+@cindex hardware breakpoints
+@cindex program counter
+Hardware breakpoints are sometimes available as a builtin debugging
+features with some chips. Typically these work by having dedicated
+register into which the breakpoint address may be stored. If the PC
+(shorthand for @dfn{program counter})
+ever matches a value in a breakpoint registers, the CPU raises an
+exception and reports it to @value{GDBN}.
+
+Another possibility is when an emulator is in use; many emulators
+include circuitry that watches the address lines coming out from the
+processor, and force it to stop if the address matches a breakpoint's
+address.
+
+A third possibility is that the target already has the ability to do
+breakpoints somehow; for instance, a ROM monitor may do its own
+software breakpoints. So although these are not literally ``hardware
+breakpoints'', from @value{GDBN}'s point of view they work the same;
+@value{GDBN} need not do nothing more than set the breakpoint and wait
+for something to happen.
+
+Since they depend on hardware resources, hardware breakpoints may be
+limited in number; when the user asks for more, @value{GDBN} will
+start trying to set software breakpoints. (On some architectures,
+notably the 32-bit x86 platforms, @value{GDBN} cannot alsways know
+whether there's enough hardware resources to insert all the hardware
+breakpoints and watchpoints. On those platforms, @value{GDBN} prints
+an error message only when the program being debugged is continued.)
+
+@cindex software breakpoints
+Software breakpoints require @value{GDBN} to do somewhat more work.
+The basic theory is that @value{GDBN} will replace a program
+instruction with a trap, illegal divide, or some other instruction
+that will cause an exception, and then when it's encountered,
+@value{GDBN} will take the exception and stop the program. When the
+user says to continue, @value{GDBN} will restore the original
+instruction, single-step, re-insert the trap, and continue on.
+
+Since it literally overwrites the program being tested, the program area
+must be writable, so this technique won't work on programs in ROM. It
+can also distort the behavior of programs that examine themselves,
+although such a situation would be highly unusual.
+
+Also, the software breakpoint instruction should be the smallest size of
+instruction, so it doesn't overwrite an instruction that might be a jump
+target, and cause disaster when the program jumps into the middle of the
+breakpoint instruction. (Strictly speaking, the breakpoint must be no
+larger than the smallest interval between instructions that may be jump
+targets; perhaps there is an architecture where only even-numbered
+instructions may jumped to.) Note that it's possible for an instruction
+set not to have any instructions usable for a software breakpoint,
+although in practice only the ARC has failed to define such an
+instruction.
+
+@findex BREAKPOINT
+The basic definition of the software breakpoint is the macro
+@code{BREAKPOINT}.
+
+Basic breakpoint object handling is in @file{breakpoint.c}. However,
+much of the interesting breakpoint action is in @file{infrun.c}.
+
+@section Single Stepping
+
+@section Signal Handling
+
+@section Thread Handling
+
+@section Inferior Function Calls
+
+@section Longjmp Support
+
+@cindex @code{longjmp} debugging
+@value{GDBN} has support for figuring out that the target is doing a
+@code{longjmp} and for stopping at the target of the jump, if we are
+stepping. This is done with a few specialized internal breakpoints,
+which are visible in the output of the @samp{maint info breakpoint}
+command.
-If you want to use GDB to debug programs that run on the new machine,
-you have to get it to understand the machine's object files, symbol
-files, and interfaces to processes; @pxref{Target,,Adding a New Target}
-and @pxref{Native,,Adding a New Native Configuration}
+@findex GET_LONGJMP_TARGET
+To make this work, you need to define a macro called
+@code{GET_LONGJMP_TARGET}, which will examine the @code{jmp_buf}
+structure and extract the longjmp target address. Since @code{jmp_buf}
+is target specific, you will need to define it in the appropriate
+@file{tm-@var{target}.h} file. Look in @file{tm-sun4os4.h} and
+@file{sparc-tdep.c} for examples of how to do this.
-Several files control GDB's configuration for host systems:
+@section Watchpoints
+@cindex watchpoints
-@table @file
-@item gdb/config/@var{arch}/@var{xxx}.mh
-Specifies Makefile fragments needed when hosting on machine @var{xxx}.
-In particular, this lists the required machine-dependent object files,
-by defining @samp{XDEPFILES=@dots{}}. Also
-specifies the header file which describes host @var{xxx}, by defining
-@samp{XM_FILE= xm-@var{xxx}.h}. You can also define @samp{CC},
-@samp{REGEX} and @samp{REGEX1}, @samp{SYSV_DEFINE}, @samp{XM_CFLAGS},
-@samp{XM_ADD_FILES}, @samp{XM_CLIBS}, @samp{XM_CDEPS},
-etc.; see @file{Makefile.in}.
+Watchpoints are a special kind of breakpoints (@pxref{Algorithms,
+breakpoints}) which break when data is accessed rather than when some
+instruction is executed. When you have data which changes without
+your knowing what code does that, watchpoints are the silver bullet to
+hunt down and kill such bugs.
-@item gdb/config/@var{arch}/xm-@var{xxx}.h
-(@file{xm.h} is a link to this file, created by configure).
-Contains C macro definitions describing the host system environment,
-such as byte order, host C compiler and library, ptrace support,
-and core file structure. Crib from existing @file{xm-*.h} files
-to create a new one.
-
-@item gdb/@var{xxx}-xdep.c
-Contains any miscellaneous C code required for this machine
-as a host. On many machines it doesn't exist at all. If it does
-exist, put @file{@var{xxx}-xdep.o} into the @code{XDEPFILES} line
-in @file{gdb/config/mh-@var{xxx}}.
-@end table
+@cindex hardware watchpoints
+@cindex software watchpoints
+Watchpoints can be either hardware-assisted or not; the latter type is
+known as ``software watchpoints.'' @value{GDBN} always uses
+hardware-assisted watchpoints if they are available, and falls back on
+software watchpoints otherwise. Typical situations where @value{GDBN}
+will use software watchpoints are:
-@subheading Generic Host Support Files
+@itemize @bullet
+@item
+The watched memory region is too large for the underlying hardware
+watchpoint support. For example, each x86 debug register can watch up
+to 4 bytes of memory, so trying to watch data structures whose size is
+more than 16 bytes will cause @value{GDBN} to use software
+watchpoints.
-There are some ``generic'' versions of routines that can be used by
-various systems. These can be customized in various ways by macros
-defined in your @file{xm-@var{xxx}.h} file. If these routines work for
-the @var{xxx} host, you can just include the generic file's name (with
-@samp{.o}, not @samp{.c}) in @code{XDEPFILES}.
+@item
+The value of the expression to be watched depends on data held in
+registers (as opposed to memory).
-Otherwise, if your machine needs custom support routines, you will need
-to write routines that perform the same functions as the generic file.
-Put them into @code{@var{xxx}-xdep.c}, and put @code{@var{xxx}-xdep.o}
-into @code{XDEPFILES}.
+@item
+Too many different watchpoints requested. (On some architectures,
+this situation is impossible to detect until the debugged program is
+resumed.) Note that x86 debug registers are used both for hardware
+breakpoints and for watchpoints, so setting too many hardware
+breakpoints might cause watchpoint insertion to fail.
-@table @file
-@item ser-bsd.c
-This contains serial line support for Berkeley-derived Unix systems.
+@item
+No hardware-assisted watchpoints provided by the target
+implementation.
+@end itemize
-@item ser-go32.c
-This contains serial line support for 32-bit programs running under DOS
-using the GO32 execution environment.
+Software watchpoints are very slow, since @value{GDBN} needs to
+single-step the program being debugged and test the value of the
+watched expression(s) after each instruction. The rest of this
+section is mostly irrelevant for software watchpoints.
-@item ser-termios.c
-This contains serial line support for System V-derived Unix systems.
-@end table
+@value{GDBN} uses several macros and primitives to support hardware
+watchpoints:
-Now, you are now ready to try configuring GDB to compile using your system
-as its host. From the top level (above @file{bfd}, @file{gdb}, etc), do:
+@table @code
+@findex TARGET_HAS_HARDWARE_WATCHPOINTS
+@item TARGET_HAS_HARDWARE_WATCHPOINTS
+If defined, the target supports hardware watchpoints.
+
+@findex TARGET_CAN_USE_HARDWARE_WATCHPOINT
+@item TARGET_CAN_USE_HARDWARE_WATCHPOINT (@var{type}, @var{count}, @var{other})
+Return the number of hardware watchpoints of type @var{type} that are
+possible to be set. The value is positive if @var{count} watchpoints
+of this type can be set, zero if setting watchpoints of this type is
+not supported, and negative if @var{count} is more than the maximum
+number of watchpoints of type @var{type} that can be set. @var{other}
+is non-zero if other types of watchpoints are currently enabled (there
+are architectures which cannot set watchpoints of different types at
+the same time).
+
+@findex TARGET_REGION_OK_FOR_HW_WATCHPOINT
+@item TARGET_REGION_OK_FOR_HW_WATCHPOINT (@var{addr}, @var{len})
+Return non-zero if hardware watchpoints can be used to watch a region
+whose address is @var{addr} and whose length in bytes is @var{len}.
+
+@findex TARGET_REGION_SIZE_OK_FOR_HW_WATCHPOINT
+@item TARGET_REGION_SIZE_OK_FOR_HW_WATCHPOINT (@var{size})
+Return non-zero if hardware watchpoints can be used to watch a region
+whose size is @var{size}. @value{GDBN} only uses this macro as a
+fall-back, in case @code{TARGET_REGION_OK_FOR_HW_WATCHPOINT} is not
+defined.
+
+@findex TARGET_DISABLE_HW_WATCHPOINTS
+@item TARGET_DISABLE_HW_WATCHPOINTS (@var{pid})
+Disables watchpoints in the process identified by @var{pid}. This is
+used, e.g., on HP-UX which provides operations to disable and enable
+the page-level memory protection that implements hardware watchpoints
+on that platform.
+
+@findex TARGET_ENABLE_HW_WATCHPOINTS
+@item TARGET_ENABLE_HW_WATCHPOINTS (@var{pid})
+Enables watchpoints in the process identified by @var{pid}. This is
+used, e.g., on HP-UX which provides operations to disable and enable
+the page-level memory protection that implements hardware watchpoints
+on that platform.
+
+@findex target_insert_watchpoint
+@findex target_remove_watchpoint
+@item target_insert_watchpoint (@var{addr}, @var{len}, @var{type})
+@itemx target_remove_watchpoint (@var{addr}, @var{len}, @var{type})
+Insert or remove a hardware watchpoint starting at @var{addr}, for
+@var{len} bytes. @var{type} is the watchpoint type, one of the
+possible values of the enumerated data type @code{target_hw_bp_type},
+defined by @file{breakpoint.h} as follows:
@example
-./configure @var{xxx} +target=vxworks960
+ enum target_hw_bp_type
+ @{
+ hw_write = 0, /* Common (write) HW watchpoint */
+ hw_read = 1, /* Read HW watchpoint */
+ hw_access = 2, /* Access (read or write) HW watchpoint */
+ hw_execute = 3 /* Execute HW breakpoint */
+ @};
@end example
-This will configure your system to cross-compile for VxWorks on
-the Intel 960, which is probably not what you really want, but it's
-a test case that works at this stage. (You haven't set up to be
-able to debug programs that run @emph{on} @var{xxx} yet.)
+@noindent
+These two macros should return 0 for success, non-zero for failure.
+
+@cindex insert or remove hardware breakpoint
+@findex target_remove_hw_breakpoint
+@findex target_insert_hw_breakpoint
+@item target_remove_hw_breakpoint (@var{addr}, @var{shadow})
+@itemx target_insert_hw_breakpoint (@var{addr}, @var{shadow})
+Insert or remove a hardware-assisted breakpoint at address @var{addr}.
+Returns zero for success, non-zero for failure. @var{shadow} is the
+real contents of the byte where the breakpoint has been inserted; it
+is generally not valid when hardware breakpoints are used, but since
+no other code touches these values, the implementations of the above
+two macros can use them for their internal purposes.
+
+@findex target_stopped_data_address
+@item target_stopped_data_address ()
+If the inferior has some watchpoint that triggered, return the address
+associated with that watchpoint. Otherwise, return zero.
+
+@findex DECR_PC_AFTER_HW_BREAK
+@item DECR_PC_AFTER_HW_BREAK
+If defined, @value{GDBN} decrements the program counter by the value
+of @code{DECR_PC_AFTER_HW_BREAK} after a hardware break-point. This
+overrides the value of @code{DECR_PC_AFTER_BREAK} when a breakpoint
+that breaks is a hardware-assisted breakpoint.
+
+@findex HAVE_STEPPABLE_WATCHPOINT
+@item HAVE_STEPPABLE_WATCHPOINT
+If defined to a non-zero value, it is not necessary to disable a
+watchpoint to step over it.
+
+@findex HAVE_NONSTEPPABLE_WATCHPOINT
+@item HAVE_NONSTEPPABLE_WATCHPOINT
+If defined to a non-zero value, @value{GDBN} should disable a
+watchpoint to step the inferior over it.
+
+@findex HAVE_CONTINUABLE_WATCHPOINT
+@item HAVE_CONTINUABLE_WATCHPOINT
+If defined to a non-zero value, it is possible to continue the
+inferior after a watchpoint has been hit.
+
+@findex CANNOT_STEP_HW_WATCHPOINTS
+@item CANNOT_STEP_HW_WATCHPOINTS
+If this is defined to a non-zero value, @value{GDBN} will remove all
+watchpoints before stepping the inferior.
+
+@findex STOPPED_BY_WATCHPOINT
+@item STOPPED_BY_WATCHPOINT (@var{wait_status})
+Return non-zero if stopped by a watchpoint. @var{wait_status} is of
+the type @code{struct target_waitstatus}, defined by @file{target.h}.
+@end table
-If this succeeds, you can try building it all with:
+@subsection x86 Watchpoints
+@cindex x86 debug registers
+@cindex watchpoints, on x86
-@example
-make
-@end example
+The 32-bit Intel x86 (a.k.a.@: ia32) processors feature special debug
+registers designed to facilitate debugging. @value{GDBN} provides a
+generic library of functions that x86-based ports can use to implement
+support for watchpoints and hardware-assisted breakpoints. This
+subsection documents the x86 watchpoint facilities in @value{GDBN}.
-Repeat until the program configures, compiles, links, and runs.
-When run, it won't be able to do much (unless you have a VxWorks/960
-board on your network) but you will know that the host support is
-pretty well done.
+To use the generic x86 watchpoint support, a port should do the
+following:
-Good luck! Comments and suggestions about this section are particularly
-welcome; send them to @samp{bug-gdb@@prep.ai.mit.edu}.
+@itemize @bullet
+@findex I386_USE_GENERIC_WATCHPOINTS
+@item
+Define the macro @code{I386_USE_GENERIC_WATCHPOINTS} somewhere in the
+target-dependent headers.
-@node Native
-@chapter Adding a New Native Configuration
+@item
+Include the @file{config/i386/nm-i386.h} header file @emph{after}
+defining @code{I386_USE_GENERIC_WATCHPOINTS}.
-If you are making GDB run native on the @var{xxx} machine, you have
-plenty more work to do. Several files control GDB's configuration for
-native support:
+@item
+Add @file{i386-nat.o} to the value of the Make variable
+@code{NATDEPFILES} (@pxref{Native Debugging, NATDEPFILES}) or
+@code{TDEPFILES} (@pxref{Target Architecture Definition, TDEPFILES}).
-@table @file
-@item gdb/config/@var{xarch}/@var{xxx}.mh
-Specifies Makefile fragments needed when hosting @emph{or native}
-on machine @var{xxx}.
-In particular, this lists the required native-dependent object files,
-by defining @samp{NATDEPFILES=@dots{}}. Also
-specifies the header file which describes native support on @var{xxx},
-by defining @samp{NAT_FILE= nm-@var{xxx}.h}.
-You can also define @samp{NAT_CFLAGS},
-@samp{NAT_ADD_FILES}, @samp{NAT_CLIBS}, @samp{NAT_CDEPS},
-etc.; see @file{Makefile.in}.
+@item
+Provide implementations for the @code{I386_DR_LOW_*} macros described
+below. Typically, each macro should call a target-specific function
+which does the real work.
+@end itemize
-@item gdb/config/@var{arch}/nm-@var{xxx}.h
-(@file{nm.h} is a link to this file, created by configure).
-Contains C macro definitions describing the native system environment,
-such as child process control and core file support.
-Crib from existing @file{nm-*.h} files to create a new one.
+The x86 watchpoint support works by maintaining mirror images of the
+debug registers. Values are copied between the mirror images and the
+real debug registers via a set of macros which each target needs to
+provide:
-@item gdb/@var{xxx}-nat.c
-Contains any miscellaneous C code required for this native support
-of this machine. On some machines it doesn't exist at all.
+@table @code
+@findex I386_DR_LOW_SET_CONTROL
+@item I386_DR_LOW_SET_CONTROL (@var{val})
+Set the Debug Control (DR7) register to the value @var{val}.
+
+@findex I386_DR_LOW_SET_ADDR
+@item I386_DR_LOW_SET_ADDR (@var{idx}, @var{addr})
+Put the address @var{addr} into the debug register number @var{idx}.
+
+@findex I386_DR_LOW_RESET_ADDR
+@item I386_DR_LOW_RESET_ADDR (@var{idx})
+Reset (i.e.@: zero out) the address stored in the debug register
+number @var{idx}.
+
+@findex I386_DR_LOW_GET_STATUS
+@item I386_DR_LOW_GET_STATUS
+Return the value of the Debug Status (DR6) register. This value is
+used immediately after it is returned by
+@code{I386_DR_LOW_GET_STATUS}, so as to support per-thread status
+register values.
@end table
-@subheading Generic Native Support Files
+For each one of the 4 debug registers (whose indices are from 0 to 3)
+that store addresses, a reference count is maintained by @value{GDBN},
+to allow sharing of debug registers by several watchpoints. This
+allows users to define several watchpoints that watch the same
+expression, but with different conditions and/or commands, without
+wasting debug registers which are in short supply. @value{GDBN}
+maintains the reference counts internally, targets don't have to do
+anything to use this feature.
+
+The x86 debug registers can each watch a region that is 1, 2, or 4
+bytes long. The ia32 architecture requires that each watched region
+be appropriately aligned: 2-byte region on 2-byte boundary, 4-byte
+region on 4-byte boundary. However, the x86 watchpoint support in
+@value{GDBN} can watch unaligned regions and regions larger than 4
+bytes (up to 16 bytes) by allocating several debug registers to watch
+a single region. This allocation of several registers per a watched
+region is also done automatically without target code intervention.
+
+The generic x86 watchpoint support provides the following API for the
+@value{GDBN}'s application code:
-There are some ``generic'' versions of routines that can be used by
-various systems. These can be customized in various ways by macros
-defined in your @file{nm-@var{xxx}.h} file. If these routines work for
-the @var{xxx} host, you can just include the generic file's name (with
-@samp{.o}, not @samp{.c}) in @code{NATDEPFILES}.
+@table @code
+@findex i386_region_ok_for_watchpoint
+@item i386_region_ok_for_watchpoint (@var{addr}, @var{len})
+The macro @code{TARGET_REGION_OK_FOR_HW_WATCHPOINT} is set to call
+this function. It counts the number of debug registers required to
+watch a given region, and returns a non-zero value if that number is
+less than 4, the number of debug registers available to x86
+processors.
+
+@findex i386_stopped_data_address
+@item i386_stopped_data_address (void)
+The macros @code{STOPPED_BY_WATCHPOINT} and
+@code{target_stopped_data_address} are set to call this function. The
+argument passed to @code{STOPPED_BY_WATCHPOINT} is ignored. This
+function examines the breakpoint condition bits in the DR6 Debug
+Status register, as returned by the @code{I386_DR_LOW_GET_STATUS}
+macro, and returns the address associated with the first bit that is
+set in DR6.
+
+@findex i386_insert_watchpoint
+@findex i386_remove_watchpoint
+@item i386_insert_watchpoint (@var{addr}, @var{len}, @var{type})
+@itemx i386_remove_watchpoint (@var{addr}, @var{len}, @var{type})
+Insert or remove a watchpoint. The macros
+@code{target_insert_watchpoint} and @code{target_remove_watchpoint}
+are set to call these functions. @code{i386_insert_watchpoint} first
+looks for a debug register which is already set to watch the same
+region for the same access types; if found, it just increments the
+reference count of that debug register, thus implementing debug
+register sharing between watchpoints. If no such register is found,
+the function looks for a vacant debug register, sets its mirrorred
+value to @var{addr}, sets the mirrorred value of DR7 Debug Control
+register as appropriate for the @var{len} and @var{type} parameters,
+and then passes the new values of the debug register and DR7 to the
+inferior by calling @code{I386_DR_LOW_SET_ADDR} and
+@code{I386_DR_LOW_SET_CONTROL}. If more than one debug register is
+required to cover the given region, the above process is repeated for
+each debug register.
+
+@code{i386_remove_watchpoint} does the opposite: it resets the address
+in the mirrorred value of the debug register and its read/write and
+length bits in the mirrorred value of DR7, then passes these new
+values to the inferior via @code{I386_DR_LOW_RESET_ADDR} and
+@code{I386_DR_LOW_SET_CONTROL}. If a register is shared by several
+watchpoints, each time a @code{i386_remove_watchpoint} is called, it
+decrements the reference count, and only calls
+@code{I386_DR_LOW_RESET_ADDR} and @code{I386_DR_LOW_SET_CONTROL} when
+the count goes to zero.
+
+@findex i386_insert_hw_breakpoint
+@findex i386_remove_hw_breakpoint
+@item i386_insert_hw_breakpoint (@var{addr}, @var{shadow}
+@itemx i386_remove_hw_breakpoint (@var{addr}, @var{shadow})
+These functions insert and remove hardware-assisted breakpoints. The
+macros @code{target_insert_hw_breakpoint} and
+@code{target_remove_hw_breakpoint} are set to call these functions.
+These functions work like @code{i386_insert_watchpoint} and
+@code{i386_remove_watchpoint}, respectively, except that they set up
+the debug registers to watch instruction execution, and each
+hardware-assisted breakpoint always requires exactly one debug
+register.
+
+@findex i386_stopped_by_hwbp
+@item i386_stopped_by_hwbp (void)
+This function returns non-zero if the inferior has some watchpoint or
+hardware breakpoint that triggered. It works like
+@code{i386_stopped_data_address}, except that it doesn't return the
+address whose watchpoint triggered.
+
+@findex i386_cleanup_dregs
+@item i386_cleanup_dregs (void)
+This function clears all the reference counts, addresses, and control
+bits in the mirror images of the debug registers. It doesn't affect
+the actual debug registers in the inferior process.
+@end table
-Otherwise, if your machine needs custom support routines, you will need
-to write routines that perform the same functions as the generic file.
-Put them into @code{@var{xxx}-nat.c}, and put @code{@var{xxx}-nat.o}
-into @code{NATDEPFILES}.
+@noindent
+@strong{Notes:}
+@enumerate 1
+@item
+x86 processors support setting watchpoints on I/O reads or writes.
+However, since no target supports this (as of March 2001), and since
+@code{enum target_hw_bp_type} doesn't even have an enumeration for I/O
+watchpoints, this feature is not yet available to @value{GDBN} running
+on x86.
-@table @file
+@item
+x86 processors can enable watchpoints locally, for the current task
+only, or globally, for all the tasks. For each debug register,
+there's a bit in the DR7 Debug Control register that determines
+whether the associated address is watched locally or globally. The
+current implementation of x86 watchpoint support in @value{GDBN}
+always sets watchpoints to be locally enabled, since global
+watchpoints might interfere with the underlying OS and are probably
+unavailable in many platforms.
+@end enumerate
-@item inftarg.c
-This contains the @emph{target_ops vector} that supports Unix child
-processes on systems which use ptrace and wait to control the child.
+@node User Interface
-@item procfs.c
-This contains the @emph{target_ops vector} that supports Unix child
-processes on systems which use /proc to control the child.
+@chapter User Interface
-@item fork-child.c
-This does the low-level grunge that uses Unix system calls
-to do a "fork and exec" to start up a child process.
+@value{GDBN} has several user interfaces. Although the command-line interface
+is the most common and most familiar, there are others.
-@item infptrace.c
-This is the low level interface to inferior processes for systems
-using the Unix @code{ptrace} call in a vanilla way.
+@section Command Interpreter
-@item coredep.c::fetch_core_registers()
-Support for reading registers out of a core file. This routine calls
-@code{register_addr()}, see below.
-Now that BFD is used to read core files, virtually all machines should
-use @code{coredep.c}, and should just provide @code{fetch_core_registers} in
-@code{@var{xxx}-nat.c} (or @code{REGISTER_U_ADDR} in @code{nm-@var{xxx}.h}).
+@cindex command interpreter
+@cindex CLI
+The command interpreter in @value{GDBN} is fairly simple. It is designed to
+allow for the set of commands to be augmented dynamically, and also
+has a recursive subcommand capability, where the first argument to
+a command may itself direct a lookup on a different command list.
-@item coredep.c::register_addr()
-If your @code{nm-@var{xxx}.h} file defines the macro
-@code{REGISTER_U_ADDR(addr, blockend, regno)}, it should be defined to
-set @code{addr} to the offset within the @samp{user}
-struct of GDB register number @code{regno}. @code{blockend} is the
-offset within the ``upage'' of @code{u.u_ar0}.
-If @code{REGISTER_U_ADDR} is defined,
-@file{coredep.c} will define the @code{register_addr()} function and use
-the macro in it. If you do not define @code{REGISTER_U_ADDR}, but you
-are using the standard @code{fetch_core_registers()}, you will need to
-define your own version of @code{register_addr()}, put it into your
-@code{@var{xxx}-nat.c} file, and be sure @code{@var{xxx}-nat.o} is in
-the @code{NATDEPFILES} list. If you have your own
-@code{fetch_core_registers()}, you may not need a separate
-@code{register_addr()}. Many custom @code{fetch_core_registers()}
-implementations simply locate the registers themselves.@refill
-@end table
+For instance, the @samp{set} command just starts a lookup on the
+@code{setlist} command list, while @samp{set thread} recurses
+to the @code{set_thread_cmd_list}.
-When making GDB run native on a new operating system,
-to make it possible to debug
-core files, you will need to either write specific code for parsing your
-OS's core files, or customize @file{bfd/trad-core.c}. First, use
-whatever @code{#include} files your machine uses to define the struct of
-registers that is accessible (possibly in the u-area) in a core file
-(rather than @file{machine/reg.h}), and an include file that defines whatever
-header exists on a core file (e.g. the u-area or a @samp{struct core}). Then
-modify @code{trad_unix_core_file_p()} to use these values to set up the
-section information for the data segment, stack segment, any other
-segments in the core file (perhaps shared library contents or control
-information), ``registers'' segment, and if there are two discontiguous
-sets of registers (e.g. integer and float), the ``reg2'' segment. This
-section information basically delimits areas in the core file in a
-standard way, which the section-reading routines in BFD know how to seek
-around in.
+@findex add_cmd
+@findex add_com
+To add commands in general, use @code{add_cmd}. @code{add_com} adds to
+the main command list, and should be used for those commands. The usual
+place to add commands is in the @code{_initialize_@var{xyz}} routines at
+the ends of most source files.
-Then back in GDB, you need a matching routine called
-@code{fetch_core_registers()}. If you can use the generic one, it's in
-@file{coredep.c}; if not, it's in your @file{@var{xxx}-nat.c} file.
-It will be passed a char pointer to the entire ``registers'' segment,
-its length, and a zero; or a char pointer to the entire ``regs2''
-segment, its length, and a 2. The routine should suck out the supplied
-register values and install them into GDB's ``registers'' array.
-(@xref{New Architectures,,Defining a New Host or Target Architecture},
-for more info about this.)
+@cindex deprecating commands
+@findex deprecate_cmd
+Before removing commands from the command set it is a good idea to
+deprecate them for some time. Use @code{deprecate_cmd} on commands or
+aliases to set the deprecated flag. @code{deprecate_cmd} takes a
+@code{struct cmd_list_element} as it's first argument. You can use the
+return value from @code{add_com} or @code{add_cmd} to deprecate the
+command immediately after it is created.
-If your system uses @file{/proc} to control processes, and uses ELF
-format core files, then you may be able to use the same routines
-for reading the registers out of processes and out of core files.
+The first time a command is used the user will be warned and offered a
+replacement (if one exists). Note that the replacement string passed to
+@code{deprecate_cmd} should be the full name of the command, i.e. the
+entire string the user should type at the command line.
-@node Target
-@chapter Adding a New Target
+@section UI-Independent Output---the @code{ui_out} Functions
+@c This section is based on the documentation written by Fernando
+@c Nasser <fnasser@redhat.com>.
-For a new target called @var{ttt}, first specify the configuration as
-described in @ref{Config,,Adding a New Configuration}. If your new
-target is the same as your new host, you've probably already done that.
+@cindex @code{ui_out} functions
+The @code{ui_out} functions present an abstraction level for the
+@value{GDBN} output code. They hide the specifics of different user
+interfaces supported by @value{GDBN}, and thus free the programmer
+from the need to write several versions of the same code, one each for
+every UI, to produce output.
-A variety of files specify attributes of the GDB target environment:
+@subsection Overview and Terminology
-@table @file
-@item gdb/config/@var{arch}/@var{ttt}.mt
-Contains a Makefile fragment specific to this target.
-Specifies what object files are needed for target @var{ttt}, by
-defining @samp{TDEPFILES=@dots{}}.
-Also specifies the header file which describes @var{ttt}, by defining
-@samp{TM_FILE= tm-@var{ttt}.h}. You can also define @samp{TM_CFLAGS},
-@samp{TM_CLIBS}, @samp{TM_CDEPS},
-and other Makefile variables here; see @file{Makefile.in}.
+In general, execution of each @value{GDBN} command produces some sort
+of output, and can even generate an input request.
-@item gdb/config/@var{arch}/tm-@var{ttt}.h
-(@file{tm.h} is a link to this file, created by configure).
-Contains macro definitions about the target machine's
-registers, stack frame format and instructions.
-Crib from existing @file{tm-*.h} files when building a new one.
+Output can be generated for the following purposes:
-@item gdb/@var{ttt}-tdep.c
-Contains any miscellaneous code required for this target machine.
-On some machines it doesn't exist at all. Sometimes the macros
-in @file{tm-@var{ttt}.h} become very complicated, so they are
-implemented as functions here instead, and the macro is simply
-defined to call the function.
-
-@item gdb/exec.c
-Defines functions for accessing files that are
-executable on the target system. These functions open and examine an
-exec file, extract data from one, write data to one, print information
-about one, etc. Now that executable files are handled with BFD, every
-target should be able to use the generic exec.c rather than its
-own custom code.
-
-@item gdb/@var{arch}-pinsn.c
-Prints (disassembles) the target machine's instructions.
-This file is usually shared with other target machines which use the
-same processor, which is why it is @file{@var{arch}-pinsn.c} rather
-than @file{@var{ttt}-pinsn.c}.
-
-@item gdb/@var{arch}-opcode.h
-Contains some large initialized
-data structures describing the target machine's instructions.
-This is a bit strange for a @file{.h} file, but it's OK since
-it is only included in one place. @file{@var{arch}-opcode.h} is shared
-between the debugger and the assembler, if the GNU assembler has been
-ported to the target machine.
+@itemize @bullet
+@item
+to display a @emph{result} of an operation;
-@item gdb/config/@var{arch}/tm-@var{arch}.h
-This often exists to describe the basic layout of the target machine's
-processor chip (registers, stack, etc).
-If used, it is included by @file{tm-@var{xxx}.h}. It can
-be shared among many targets that use the same processor.
+@item
+to convey @emph{info} or produce side-effects of a requested
+operation;
-@item gdb/@var{arch}-tdep.c
-Similarly, there are often common subroutines that are shared by all
-target machines that use this particular architecture.
-@end table
+@item
+to provide a @emph{notification} of an asynchronous event (including
+progress indication of a prolonged asynchronous operation);
-When adding support for a new target machine, there are various areas
-of support that might need change, or might be OK.
+@item
+to display @emph{error messages} (including warnings);
-If you are using an existing object file format (a.out or COFF),
-there is probably little to be done. See @file{bfd/doc/bfd.texinfo}
-for more information on writing new a.out or COFF versions.
+@item
+to show @emph{debug data};
-If you need to add a new object file format, you must first add it to
-BFD. This is beyond the scope of this document right now. Basically
-you must build a transfer vector (of type @code{bfd_target}), which will
-mean writing all the required routines, and add it to the list in
-@file{bfd/targets.c}.
+@item
+to @emph{query} or prompt a user for input (a special case).
+@end itemize
-You must then arrange for the BFD code to provide access to the
-debugging symbols. Generally GDB will have to call swapping routines
-from BFD and a few other BFD internal routines to locate the debugging
-information. As much as possible, GDB should not depend on the BFD
-internal data structures.
+@noindent
+This section mainly concentrates on how to build result output,
+although some of it also applies to other kinds of output.
-For some targets (e.g., COFF), there is a special transfer vector used
-to call swapping routines, since the external data structures on various
-platforms have different sizes and layouts. Specialized routines that
-will only ever be implemented by one object file format may be called
-directly. This interface should be described in a file
-@file{bfd/libxxx.h}, which is included by GDB.
+Generation of output that displays the results of an operation
+involves one or more of the following:
-If you are adding a new operating system for an existing CPU chip, add a
-@file{tm-@var{xos}.h} file that describes the operating system
-facilities that are unusual (extra symbol table info; the breakpoint
-instruction needed; etc). Then write a
-@file{tm-@var{xarch}-@var{xos}.h} that just @code{#include}s
-@file{tm-@var{xarch}.h} and @file{tm-@var{xos}.h}. (Now that we have
-three-part configuration names, this will probably get revised to
-separate the @var{xos} configuration from the @var{xarch}
-configuration.)
+@itemize @bullet
+@item
+output of the actual data
+@item
+formatting the output as appropriate for console output, to make it
+easily readable by humans
-@node Languages
-@chapter Adding a Source Language to GDB
+@item
+machine oriented formatting--a more terse formatting to allow for easy
+parsing by programs which read @value{GDBN}'s output
-To add other languages to GDB's expression parser, follow the following steps:
+@item
+annotation, whose purpose is to help legacy GUIs to identify interesting
+parts in the output
+@end itemize
-@table @emph
-@item Create the expression parser.
+The @code{ui_out} routines take care of the first three aspects.
+Annotations are provided by separate annotation routines. Note that use
+of annotations for an interface between a GUI and @value{GDBN} is
+deprecated.
-This should reside in a file @file{@var{lang}-exp.y}. Routines for building
-parsed expressions into a @samp{union exp_element} list are in @file{parse.c}.
+Output can be in the form of a single item, which we call a @dfn{field};
+a @dfn{list} consisting of identical fields; a @dfn{tuple} consisting of
+non-identical fields; or a @dfn{table}, which is a tuple consisting of a
+header and a body. In a BNF-like form:
-Since we can't depend upon everyone having Bison, and YACC produces
-parsers that define a bunch of global names, the following lines
-@emph{must} be included at the top of the YACC parser, to prevent
-the various parsers from defining the same global names:
+@table @code
+@item <table> @expansion{}
+@code{<header> <body>}
+@item <header> @expansion{}
+@code{@{ <column> @}}
+@item <column> @expansion{}
+@code{<width> <alignment> <title>}
+@item <body> @expansion{}
+@code{@{<row>@}}
+@end table
-@example
-#define yyparse @var{lang}_parse
-#define yylex @var{lang}_lex
-#define yyerror @var{lang}_error
-#define yylval @var{lang}_lval
-#define yychar @var{lang}_char
-#define yydebug @var{lang}_debug
-#define yypact @var{lang}_pact
-#define yyr1 @var{lang}_r1
-#define yyr2 @var{lang}_r2
-#define yydef @var{lang}_def
-#define yychk @var{lang}_chk
-#define yypgo @var{lang}_pgo
-#define yyact @var{lang}_act
-#define yyexca @var{lang}_exca
-#define yyerrflag @var{lang}_errflag
-#define yynerrs @var{lang}_nerrs
-@end example
-At the bottom of your parser, define a @code{struct language_defn} and
-initialize it with the right values for your language. Define an
-@code{initialize_@var{lang}} routine and have it call
-@samp{add_language(@var{lang}_language_defn)} to tell the rest of GDB
-that your language exists. You'll need some other supporting variables
-and functions, which will be used via pointers from your
-@code{@var{lang}_language_defn}. See the declaration of @code{struct
-language_defn} in @file{language.h}, and the other @file{*-exp.y} files,
-for more information.
+@subsection General Conventions
-@item Add any evaluation routines, if necessary
+Most @code{ui_out} routines are of type @code{void}, the exceptions are
+@code{ui_out_stream_new} (which returns a pointer to the newly created
+object) and the @code{make_cleanup} routines.
-If you need new opcodes (that represent the operations of the language),
-add them to the enumerated type in @file{expression.h}. Add support
-code for these operations in @code{eval.c:evaluate_subexp()}. Add cases
-for new opcodes in two functions from @file{parse.c}:
-@code{prefixify_subexp()} and @code{length_of_subexp()}. These compute
-the number of @code{exp_element}s that a given operation takes up.
+The first parameter is always the @code{ui_out} vector object, a pointer
+to a @code{struct ui_out}.
-@item Update some existing code
+The @var{format} parameter is like in @code{printf} family of functions.
+When it is present, there must also be a variable list of arguments
+sufficient used to satisfy the @code{%} specifiers in the supplied
+format.
-Add an enumerated identifier for your language to the enumerated type
-@code{enum language} in @file{defs.h}.
+When a character string argument is not used in a @code{ui_out} function
+call, a @code{NULL} pointer has to be supplied instead.
-Update the routines in @file{language.c} so your language is included. These
-routines include type predicates and such, which (in some cases) are
-language dependent. If your language does not appear in the switch
-statement, an error is reported.
-Also included in @file{language.c} is the code that updates the variable
-@code{current_language}, and the routines that translate the
-@code{language_@var{lang}} enumerated identifier into a printable
-string.
+@subsection Table, Tuple and List Functions
-Update the function @code{_initialize_language} to include your language. This
-function picks the default language upon startup, so is dependent upon
-which languages that GDB is built for.
+@cindex list output functions
+@cindex table output functions
+@cindex tuple output functions
+This section introduces @code{ui_out} routines for building lists,
+tuples and tables. The routines to output the actual data items
+(fields) are presented in the next section.
-Update @code{allocate_symtab} in @file{symfile.c} and/or symbol-reading
-code so that the language of each symtab (source file) is set properly.
-This is used to determine the language to use at each stack frame level.
-Currently, the language is set based upon the extension of the source
-file. If the language can be better inferred from the symbol
-information, please set the language of the symtab in the symbol-reading
-code.
+To recap: A @dfn{tuple} is a sequence of @dfn{fields}, each field
+containing information about an object; a @dfn{list} is a sequence of
+fields where each field describes an identical object.
-Add helper code to @code{expprint.c:print_subexp()} to handle any new
-expression opcodes you have added to @file{expression.h}. Also, add the
-printed representations of your operators to @code{op_print_tab}.
+Use the @dfn{table} functions when your output consists of a list of
+rows (tuples) and the console output should include a heading. Use this
+even when you are listing just one object but you still want the header.
-@item Add a place of call
+@cindex nesting level in @code{ui_out} functions
+Tables can not be nested. Tuples and lists can be nested up to a
+maximum of five levels.
-Add a call to @code{@var{lang}_parse()} and @code{@var{lang}_error} in
-@code{parse.c:parse_exp_1()}.
+The overall structure of the table output code is something like this:
-@item Use macros to trim code
+@example
+ ui_out_table_begin
+ ui_out_table_header
+ @dots{}
+ ui_out_table_body
+ ui_out_tuple_begin
+ ui_out_field_*
+ @dots{}
+ ui_out_tuple_end
+ @dots{}
+ ui_out_table_end
+@end example
-The user has the option of building GDB for some or all of the
-languages. If the user decides to build GDB for the language
-@var{lang}, then every file dependent on @file{language.h} will have the
-macro @code{_LANG_@var{lang}} defined in it. Use @code{#ifdef}s to
-leave out large routines that the user won't need if he or she is not
-using your language.
+Here is the description of table-, tuple- and list-related @code{ui_out}
+functions:
+
+@deftypefun void ui_out_table_begin (struct ui_out *@var{uiout}, int @var{nbrofcols}, int @var{nr_rows}, const char *@var{tblid})
+The function @code{ui_out_table_begin} marks the beginning of the output
+of a table. It should always be called before any other @code{ui_out}
+function for a given table. @var{nbrofcols} is the number of columns in
+the table. @var{nr_rows} is the number of rows in the table.
+@var{tblid} is an optional string identifying the table. The string
+pointed to by @var{tblid} is copied by the implementation of
+@code{ui_out_table_begin}, so the application can free the string if it
+was @code{malloc}ed.
+
+The companion function @code{ui_out_table_end}, described below, marks
+the end of the table's output.
+@end deftypefun
+
+@deftypefun void ui_out_table_header (struct ui_out *@var{uiout}, int @var{width}, enum ui_align @var{alignment}, const char *@var{colhdr})
+@code{ui_out_table_header} provides the header information for a single
+table column. You call this function several times, one each for every
+column of the table, after @code{ui_out_table_begin}, but before
+@code{ui_out_table_body}.
+
+The value of @var{width} gives the column width in characters. The
+value of @var{alignment} is one of @code{left}, @code{center}, and
+@code{right}, and it specifies how to align the header: left-justify,
+center, or right-justify it. @var{colhdr} points to a string that
+specifies the column header; the implementation copies that string, so
+column header strings in @code{malloc}ed storage can be freed after the
+call.
+@end deftypefun
+
+@deftypefun void ui_out_table_body (struct ui_out *@var{uiout})
+This function delimits the table header from the table body.
+@end deftypefun
+
+@deftypefun void ui_out_table_end (struct ui_out *@var{uiout})
+This function signals the end of a table's output. It should be called
+after the table body has been produced by the list and field output
+functions.
-Note that you do not need to do this in your YACC parser, since if GDB
-is not build for @var{lang}, then @file{@var{lang}-exp.tab.o} (the
-compiled form of your parser) is not linked into GDB at all.
+There should be exactly one call to @code{ui_out_table_end} for each
+call to @code{ui_out_table_begin}, otherwise the @code{ui_out} functions
+will signal an internal error.
+@end deftypefun
+
+The output of the tuples that represent the table rows must follow the
+call to @code{ui_out_table_body} and precede the call to
+@code{ui_out_table_end}. You build a tuple by calling
+@code{ui_out_tuple_begin} and @code{ui_out_tuple_end}, with suitable
+calls to functions which actually output fields between them.
+
+@deftypefun void ui_out_tuple_begin (struct ui_out *@var{uiout}, const char *@var{id})
+This function marks the beginning of a tuple output. @var{id} points
+to an optional string that identifies the tuple; it is copied by the
+implementation, and so strings in @code{malloc}ed storage can be freed
+after the call.
+@end deftypefun
+
+@deftypefun void ui_out_tuple_end (struct ui_out *@var{uiout})
+This function signals an end of a tuple output. There should be exactly
+one call to @code{ui_out_tuple_end} for each call to
+@code{ui_out_tuple_begin}, otherwise an internal @value{GDBN} error will
+be signaled.
+@end deftypefun
+
+@deftypefun struct cleanup *make_cleanup_ui_out_tuple_begin_end (struct ui_out *@var{uiout}, const char *@var{id})
+This function first opens the tuple and then establishes a cleanup
+(@pxref{Coding, Cleanups}) to close the tuple. It provides a convenient
+and correct implementation of the non-portable@footnote{The function
+cast is not portable ISO-C.} code sequence:
+@smallexample
+struct cleanup *old_cleanup;
+ui_out_tuple_begin (uiout, "...");
+old_cleanup = make_cleanup ((void(*)(void *)) ui_out_tuple_end,
+ uiout);
+@end smallexample
+@end deftypefun
+
+@deftypefun void ui_out_list_begin (struct ui_out *@var{uiout}, const char *@var{id})
+This function marks the beginning of a list output. @var{id} points to
+an optional string that identifies the list; it is copied by the
+implementation, and so strings in @code{malloc}ed storage can be freed
+after the call.
+@end deftypefun
+
+@deftypefun void ui_out_list_end (struct ui_out *@var{uiout})
+This function signals an end of a list output. There should be exactly
+one call to @code{ui_out_list_end} for each call to
+@code{ui_out_list_begin}, otherwise an internal @value{GDBN} error will
+be signaled.
+@end deftypefun
+
+@deftypefun struct cleanup *make_cleanup_ui_out_list_begin_end (struct ui_out *@var{uiout}, const char *@var{id})
+Similar to @code{make_cleanup_ui_out_tuple_begin_end}, this function
+opens a list and then establishes cleanup (@pxref{Coding, Cleanups})
+that will close the list.list.
+@end deftypefun
+
+@subsection Item Output Functions
+
+@cindex item output functions
+@cindex field output functions
+@cindex data output
+The functions described below produce output for the actual data
+items, or fields, which contain information about the object.
+
+Choose the appropriate function accordingly to your particular needs.
+
+@deftypefun void ui_out_field_fmt (struct ui_out *@var{uiout}, char *@var{fldname}, char *@var{format}, ...)
+This is the most general output function. It produces the
+representation of the data in the variable-length argument list
+according to formatting specifications in @var{format}, a
+@code{printf}-like format string. The optional argument @var{fldname}
+supplies the name of the field. The data items themselves are
+supplied as additional arguments after @var{format}.
+
+This generic function should be used only when it is not possible to
+use one of the specialized versions (see below).
+@end deftypefun
+
+@deftypefun void ui_out_field_int (struct ui_out *@var{uiout}, const char *@var{fldname}, int @var{value})
+This function outputs a value of an @code{int} variable. It uses the
+@code{"%d"} output conversion specification. @var{fldname} specifies
+the name of the field.
+@end deftypefun
+
+@deftypefun void ui_out_field_core_addr (struct ui_out *@var{uiout}, const char *@var{fldname}, CORE_ADDR @var{address})
+This function outputs an address.
+@end deftypefun
+
+@deftypefun void ui_out_field_string (struct ui_out *@var{uiout}, const char *@var{fldname}, const char *@var{string})
+This function outputs a string using the @code{"%s"} conversion
+specification.
+@end deftypefun
+
+Sometimes, there's a need to compose your output piece by piece using
+functions that operate on a stream, such as @code{value_print} or
+@code{fprintf_symbol_filtered}. These functions accept an argument of
+the type @code{struct ui_file *}, a pointer to a @code{ui_file} object
+used to store the data stream used for the output. When you use one
+of these functions, you need a way to pass their results stored in a
+@code{ui_file} object to the @code{ui_out} functions. To this end,
+you first create a @code{ui_stream} object by calling
+@code{ui_out_stream_new}, pass the @code{stream} member of that
+@code{ui_stream} object to @code{value_print} and similar functions,
+and finally call @code{ui_out_field_stream} to output the field you
+constructed. When the @code{ui_stream} object is no longer needed,
+you should destroy it and free its memory by calling
+@code{ui_out_stream_delete}.
+
+@deftypefun struct ui_stream *ui_out_stream_new (struct ui_out *@var{uiout})
+This function creates a new @code{ui_stream} object which uses the
+same output methods as the @code{ui_out} object whose pointer is
+passed in @var{uiout}. It returns a pointer to the newly created
+@code{ui_stream} object.
+@end deftypefun
+
+@deftypefun void ui_out_stream_delete (struct ui_stream *@var{streambuf})
+This functions destroys a @code{ui_stream} object specified by
+@var{streambuf}.
+@end deftypefun
+
+@deftypefun void ui_out_field_stream (struct ui_out *@var{uiout}, const char *@var{fieldname}, struct ui_stream *@var{streambuf})
+This function consumes all the data accumulated in
+@code{streambuf->stream} and outputs it like
+@code{ui_out_field_string} does. After a call to
+@code{ui_out_field_stream}, the accumulated data no longer exists, but
+the stream is still valid and may be used for producing more fields.
+@end deftypefun
+
+@strong{Important:} If there is any chance that your code could bail
+out before completing output generation and reaching the point where
+@code{ui_out_stream_delete} is called, it is necessary to set up a
+cleanup, to avoid leaking memory and other resources. Here's a
+skeleton code to do that:
+
+@smallexample
+ struct ui_stream *mybuf = ui_out_stream_new (uiout);
+ struct cleanup *old = make_cleanup (ui_out_stream_delete, mybuf);
+ ...
+ do_cleanups (old);
+@end smallexample
+
+If the function already has the old cleanup chain set (for other kinds
+of cleanups), you just have to add your cleanup to it:
+
+@smallexample
+ mybuf = ui_out_stream_new (uiout);
+ make_cleanup (ui_out_stream_delete, mybuf);
+@end smallexample
+
+Note that with cleanups in place, you should not call
+@code{ui_out_stream_delete} directly, or you would attempt to free the
+same buffer twice.
+
+@subsection Utility Output Functions
+
+@deftypefun void ui_out_field_skip (struct ui_out *@var{uiout}, const char *@var{fldname})
+This function skips a field in a table. Use it if you have to leave
+an empty field without disrupting the table alignment. The argument
+@var{fldname} specifies a name for the (missing) filed.
+@end deftypefun
+
+@deftypefun void ui_out_text (struct ui_out *@var{uiout}, const char *@var{string})
+This function outputs the text in @var{string} in a way that makes it
+easy to be read by humans. For example, the console implementation of
+this method filters the text through a built-in pager, to prevent it
+from scrolling off the visible portion of the screen.
+
+Use this function for printing relatively long chunks of text around
+the actual field data: the text it produces is not aligned according
+to the table's format. Use @code{ui_out_field_string} to output a
+string field, and use @code{ui_out_message}, described below, to
+output short messages.
+@end deftypefun
+
+@deftypefun void ui_out_spaces (struct ui_out *@var{uiout}, int @var{nspaces})
+This function outputs @var{nspaces} spaces. It is handy to align the
+text produced by @code{ui_out_text} with the rest of the table or
+list.
+@end deftypefun
+
+@deftypefun void ui_out_message (struct ui_out *@var{uiout}, int @var{verbosity}, const char *@var{format}, ...)
+This function produces a formatted message, provided that the current
+verbosity level is at least as large as given by @var{verbosity}. The
+current verbosity level is specified by the user with the @samp{set
+verbositylevel} command.@footnote{As of this writing (April 2001),
+setting verbosity level is not yet implemented, and is always returned
+as zero. So calling @code{ui_out_message} with a @var{verbosity}
+argument more than zero will cause the message to never be printed.}
+@end deftypefun
+
+@deftypefun void ui_out_wrap_hint (struct ui_out *@var{uiout}, char *@var{indent})
+This function gives the console output filter (a paging filter) a hint
+of where to break lines which are too long. Ignored for all other
+output consumers. @var{indent}, if non-@code{NULL}, is the string to
+be printed to indent the wrapped text on the next line; it must remain
+accessible until the next call to @code{ui_out_wrap_hint}, or until an
+explicit newline is produced by one of the other functions. If
+@var{indent} is @code{NULL}, the wrapped text will not be indented.
+@end deftypefun
+
+@deftypefun void ui_out_flush (struct ui_out *@var{uiout})
+This function flushes whatever output has been accumulated so far, if
+the UI buffers output.
+@end deftypefun
+
+
+@subsection Examples of Use of @code{ui_out} functions
+
+@cindex using @code{ui_out} functions
+@cindex @code{ui_out} functions, usage examples
+This section gives some practical examples of using the @code{ui_out}
+functions to generalize the old console-oriented code in
+@value{GDBN}. The examples all come from functions defined on the
+@file{breakpoints.c} file.
+
+This example, from the @code{breakpoint_1} function, shows how to
+produce a table.
+
+The original code was:
-See the file @file{configure.in} for how GDB is configured for different
-languages.
+@example
+ if (!found_a_breakpoint++)
+ @{
+ annotate_breakpoints_headers ();
+
+ annotate_field (0);
+ printf_filtered ("Num ");
+ annotate_field (1);
+ printf_filtered ("Type ");
+ annotate_field (2);
+ printf_filtered ("Disp ");
+ annotate_field (3);
+ printf_filtered ("Enb ");
+ if (addressprint)
+ @{
+ annotate_field (4);
+ printf_filtered ("Address ");
+ @}
+ annotate_field (5);
+ printf_filtered ("What\n");
+
+ annotate_breakpoints_table ();
+ @}
+@end example
-@item Edit @file{Makefile.in}
-
-Add dependencies in @file{Makefile.in}. Make sure you update the macro
-variables such as @code{HFILES} and @code{OBJS}, otherwise your code may
-not get linked in, or, worse yet, it may not get @code{tar}red into the
-distribution!
-@end table
+Here's the new version:
+@example
+ nr_printable_breakpoints = @dots{};
+
+ if (addressprint)
+ ui_out_table_begin (ui, 6, nr_printable_breakpoints, "BreakpointTable");
+ else
+ ui_out_table_begin (ui, 5, nr_printable_breakpoints, "BreakpointTable");
+
+ if (nr_printable_breakpoints > 0)
+ annotate_breakpoints_headers ();
+ if (nr_printable_breakpoints > 0)
+ annotate_field (0);
+ ui_out_table_header (uiout, 3, ui_left, "number", "Num"); /* 1 */
+ if (nr_printable_breakpoints > 0)
+ annotate_field (1);
+ ui_out_table_header (uiout, 14, ui_left, "type", "Type"); /* 2 */
+ if (nr_printable_breakpoints > 0)
+ annotate_field (2);
+ ui_out_table_header (uiout, 4, ui_left, "disp", "Disp"); /* 3 */
+ if (nr_printable_breakpoints > 0)
+ annotate_field (3);
+ ui_out_table_header (uiout, 3, ui_left, "enabled", "Enb"); /* 4 */
+ if (addressprint)
+ @{
+ if (nr_printable_breakpoints > 0)
+ annotate_field (4);
+ if (TARGET_ADDR_BIT <= 32)
+ ui_out_table_header (uiout, 10, ui_left, "addr", "Address");/* 5 */
+ else
+ ui_out_table_header (uiout, 18, ui_left, "addr", "Address");/* 5 */
+ @}
+ if (nr_printable_breakpoints > 0)
+ annotate_field (5);
+ ui_out_table_header (uiout, 40, ui_noalign, "what", "What"); /* 6 */
+ ui_out_table_body (uiout);
+ if (nr_printable_breakpoints > 0)
+ annotate_breakpoints_table ();
+@end example
-@node Releases
-@chapter Configuring GDB for Release
+This example, from the @code{print_one_breakpoint} function, shows how
+to produce the actual data for the table whose structure was defined
+in the above example. The original code was:
-From the top level directory (containing @file{gdb}, @file{bfd},
-@file{libiberty}, and so on):
@example
-make -f Makefile.in gdb.tar.Z
+ annotate_record ();
+ annotate_field (0);
+ printf_filtered ("%-3d ", b->number);
+ annotate_field (1);
+ if ((int)b->type > (sizeof(bptypes)/sizeof(bptypes[0]))
+ || ((int) b->type != bptypes[(int) b->type].type))
+ internal_error ("bptypes table does not describe type #%d.",
+ (int)b->type);
+ printf_filtered ("%-14s ", bptypes[(int)b->type].description);
+ annotate_field (2);
+ printf_filtered ("%-4s ", bpdisps[(int)b->disposition]);
+ annotate_field (3);
+ printf_filtered ("%-3c ", bpenables[(int)b->enable]);
+ @dots{}
@end example
-This will properly configure, clean, rebuild any files that are
-distributed pre-built (e.g. @file{c-exp.tab.c} or @file{refcard.ps}),
-and will then make a tarfile. (If the top level directory has already
-beenn configured, you can just do @code{make gdb.tar.Z} instead.)
+This is the new version:
-This procedure requires:
-@itemize @bullet
-@item symbolic links
-@item @code{makeinfo} (texinfo2 level)
-@item @TeX{}
-@item @code{dvips}
-@item @code{yacc} or @code{bison}
-@end itemize
-@noindent
-@dots{} and the usual slew of utilities (@code{sed}, @code{tar}, etc.).
+@example
+ annotate_record ();
+ ui_out_tuple_begin (uiout, "bkpt");
+ annotate_field (0);
+ ui_out_field_int (uiout, "number", b->number);
+ annotate_field (1);
+ if (((int) b->type > (sizeof (bptypes) / sizeof (bptypes[0])))
+ || ((int) b->type != bptypes[(int) b->type].type))
+ internal_error ("bptypes table does not describe type #%d.",
+ (int) b->type);
+ ui_out_field_string (uiout, "type", bptypes[(int)b->type].description);
+ annotate_field (2);
+ ui_out_field_string (uiout, "disp", bpdisps[(int)b->disposition]);
+ annotate_field (3);
+ ui_out_field_fmt (uiout, "enabled", "%c", bpenables[(int)b->enable]);
+ @dots{}
+@end example
-@subheading TEMPORARY RELEASE PROCEDURE FOR DOCUMENTATION
+This example, also from @code{print_one_breakpoint}, shows how to
+produce a complicated output field using the @code{print_expression}
+functions which requires a stream to be passed. It also shows how to
+automate stream destruction with cleanups. The original code was:
-@file{gdb.texinfo} is currently marked up using the texinfo-2 macros,
-which are not yet a default for anything (but we have to start using
-them sometime).
+@example
+ annotate_field (5);
+ print_expression (b->exp, gdb_stdout);
+@end example
-For making paper, the only thing this implies is the right generation of
-@file{texinfo.tex} needs to be included in the distribution.
+The new version is:
-For making info files, however, rather than duplicating the texinfo2
-distribution, generate @file{gdb-all.texinfo} locally, and include the files
-@file{gdb.info*} in the distribution. Note the plural; @code{makeinfo} will
-split the document into one overall file and five or so included files.
+@example
+ struct ui_stream *stb = ui_out_stream_new (uiout);
+ struct cleanup *old_chain = make_cleanup_ui_out_stream_delete (stb);
+ ...
+ annotate_field (5);
+ print_expression (b->exp, stb->stream);
+ ui_out_field_stream (uiout, "what", local_stream);
+@end example
+This example, also from @code{print_one_breakpoint}, shows how to use
+@code{ui_out_text} and @code{ui_out_field_string}. The original code
+was:
-@node Partial Symbol Tables
-@chapter Partial Symbol Tables
+@example
+ annotate_field (5);
+ if (b->dll_pathname == NULL)
+ printf_filtered ("<any library> ");
+ else
+ printf_filtered ("library \"%s\" ", b->dll_pathname);
+@end example
-GDB has three types of symbol tables.
+It became:
-@itemize @bullet
-@item full symbol tables (symtabs). These contain the main
-information about symbols and addresses.
-@item partial symbol tables (psymtabs). These contain enough
-information to know when to read the corresponding
-part of the full symbol table.
-@item minimal symbol tables (msymtabs). These contain information
-gleaned from non-debugging symbols.
-@end itemize
+@example
+ annotate_field (5);
+ if (b->dll_pathname == NULL)
+ @{
+ ui_out_field_string (uiout, "what", "<any library>");
+ ui_out_spaces (uiout, 1);
+ @}
+ else
+ @{
+ ui_out_text (uiout, "library \"");
+ ui_out_field_string (uiout, "what", b->dll_pathname);
+ ui_out_text (uiout, "\" ");
+ @}
+@end example
-This section describes partial symbol tables.
+The following example from @code{print_one_breakpoint} shows how to
+use @code{ui_out_field_int} and @code{ui_out_spaces}. The original
+code was:
-A psymtab is constructed by doing a very quick pass over an executable
-file's debugging information. Small amounts of information are
-extracted -- enough to identify which parts of the symbol table will
-need to be re-read and fully digested later, when the user needs the
-information. The speed of this pass causes GDB to start up very
-quickly. Later, as the detailed rereading occurs, it occurs in small
-pieces, at various times, and the delay therefrom is mostly invisible to
-the user. (@xref{Symbol Reading}.)
+@example
+ annotate_field (5);
+ if (b->forked_inferior_pid != 0)
+ printf_filtered ("process %d ", b->forked_inferior_pid);
+@end example
-The symbols that show up in a file's psymtab should be, roughly, those
-visible to the debugger's user when the program is not running code from
-that file. These include external symbols and types, static
-symbols and types, and enum values declared at file scope.
+It became:
-The psymtab also contains the range of instruction addresses that the
-full symbol table would represent.
+@example
+ annotate_field (5);
+ if (b->forked_inferior_pid != 0)
+ @{
+ ui_out_text (uiout, "process ");
+ ui_out_field_int (uiout, "what", b->forked_inferior_pid);
+ ui_out_spaces (uiout, 1);
+ @}
+@end example
-The idea is that there are only two ways for the user (or much of
-the code in the debugger) to reference a symbol:
+Here's an example of using @code{ui_out_field_string}. The original
+code was:
-@itemize @bullet
+@example
+ annotate_field (5);
+ if (b->exec_pathname != NULL)
+ printf_filtered ("program \"%s\" ", b->exec_pathname);
+@end example
-@item by its address
-(e.g. execution stops at some address which is inside a function
-in this file). The address will be noticed to be in the
-range of this psymtab, and the full symtab will be read in.
-@code{find_pc_function}, @code{find_pc_line}, and other @code{find_pc_@dots{}}
-functions handle this.
+It became:
-@item by its name
-(e.g. the user asks to print a variable, or set a breakpoint on a
-function). Global names and file-scope names will be found in the
-psymtab, which will cause the symtab to be pulled in. Local names will
-have to be qualified by a global name, or a file-scope name, in which
-case we will have already read in the symtab as we evaluated the
-qualifier. Or, a local symbol can be referenced when
-we are "in" a local scope, in which case the first case applies.
-@code{lookup_symbol} does most of the work here.
+@example
+ annotate_field (5);
+ if (b->exec_pathname != NULL)
+ @{
+ ui_out_text (uiout, "program \"");
+ ui_out_field_string (uiout, "what", b->exec_pathname);
+ ui_out_text (uiout, "\" ");
+ @}
+@end example
-@end itemize
+Finally, here's an example of printing an address. The original code:
-The only reason that psymtabs exist is to cause a symtab to be read in
-at the right moment. Any symbol that can be elided from a psymtab,
-while still causing that to happen, should not appear in it. Since
-psymtabs don't have the idea of scope, you can't put local symbols in
-them anyway. Psymtabs don't have the idea of the type of a symbol,
-either, so types need not appear, unless they will be referenced by
-name.
+@example
+ annotate_field (4);
+ printf_filtered ("%s ",
+ local_hex_string_custom ((unsigned long) b->address, "08l"));
+@end example
-It is a bug for GDB to behave one way when only a psymtab has been read,
-and another way if the corresponding symtab has been read in. Such
-bugs are typically caused by a psymtab that does not contain all the
-visible symbols, or which has the wrong instruction address ranges.
+It became:
-The psymtab for a particular section of a symbol-file (objfile)
-could be thrown away after the symtab has been read in. The symtab
-should always be searched before the psymtab, so the psymtab will
-never be used (in a bug-free environment). Currently,
-psymtabs are allocated on an obstack, and all the psymbols themselves
-are allocated in a pair of large arrays on an obstack, so there is
-little to be gained by trying to free them unless you want to do a lot
-more work.
+@example
+ annotate_field (4);
+ ui_out_field_core_addr (uiout, "Address", b->address);
+@end example
-@node Types
-@chapter Types
-Fundamental Types (e.g., FT_VOID, FT_BOOLEAN).
+@section Console Printing
-These are the fundamental types that gdb uses internally. Fundamental
-types from the various debugging formats (stabs, ELF, etc) are mapped into
-one of these. They are basically a union of all fundamental types that
-gdb knows about for all the languages that gdb knows about.
+@section TUI
-Type Codes (e.g., TYPE_CODE_PTR, TYPE_CODE_ARRAY).
+@node libgdb
-Each time gdb builds an internal type, it marks it with one of these
-types. The type may be a fundamental type, such as TYPE_CODE_INT, or
-a derived type, such as TYPE_CODE_PTR which is a pointer to another
-type. Typically, several FT_* types map to one TYPE_CODE_* type, and
-are distinguished by other members of the type struct, such as whether
-the type is signed or unsigned, and how many bits it uses.
+@chapter libgdb
-Builtin Types (e.g., builtin_type_void, builtin_type_char).
+@section libgdb 1.0
+@cindex @code{libgdb}
+@code{libgdb} 1.0 was an abortive project of years ago. The theory was
+to provide an API to @value{GDBN}'s functionality.
-These are instances of type structs that roughly correspond to fundamental
-types and are created as global types for gdb to use for various ugly
-historical reasons. We eventually want to eliminate these. Note for
-example that builtin_type_int initialized in gdbtypes.c is basically the
-same as a TYPE_CODE_INT type that is initialized in c-lang.c for an
-FT_INTEGER fundamental type. The difference is that the builtin_type is
-not associated with any particular objfile, and only one instance exists,
-while c-lang.c builds as many TYPE_CODE_INT types as needed, with each
-one associated with some particular objfile.
+@section libgdb 2.0
+@cindex @code{libgdb}
+@code{libgdb} 2.0 is an ongoing effort to update @value{GDBN} so that is
+better able to support graphical and other environments.
-@node BFD support for GDB
-@chapter Binary File Descriptor Library Support for GDB
+Since @code{libgdb} development is on-going, its architecture is still
+evolving. The following components have so far been identified:
-BFD provides support for GDB in several ways:
+@itemize @bullet
+@item
+Observer - @file{gdb-events.h}.
+@item
+Builder - @file{ui-out.h}
+@item
+Event Loop - @file{event-loop.h}
+@item
+Library - @file{gdb.h}
+@end itemize
-@table @emph
-@item identifying executable and core files
-BFD will identify a variety of file types, including a.out, coff, and
-several variants thereof, as well as several kinds of core files.
+The model that ties these components together is described below.
-@item access to sections of files
-BFD parses the file headers to determine the names, virtual addresses,
-sizes, and file locations of all the various named sections in files
-(such as the text section or the data section). GDB simply calls
-BFD to read or write section X at byte offset Y for length Z.
+@section The @code{libgdb} Model
-@item specialized core file support
-BFD provides routines to determine the failing command name stored
-in a core file, the signal with which the program failed, and whether
-a core file matches (i.e. could be a core dump of) a particular executable
-file.
+A client of @code{libgdb} interacts with the library in two ways.
-@item locating the symbol information
-GDB uses an internal interface of BFD to determine where to find the
-symbol information in an executable file or symbol-file. GDB itself
-handles the reading of symbols, since BFD does not ``understand'' debug
-symbols, but GDB uses BFD's cached information to find the symbols,
-string table, etc.
-@end table
+@itemize @bullet
+@item
+As an observer (using @file{gdb-events}) receiving notifications from
+@code{libgdb} of any internal state changes (break point changes, run
+state, etc).
+@item
+As a client querying @code{libgdb} (using the @file{ui-out} builder) to
+obtain various status values from @value{GDBN}.
+@end itemize
-@c The interface for symbol reading is described in @ref{Symbol
-@c Reading,,Symbol Reading}.
+Since @code{libgdb} could have multiple clients (e.g. a GUI supporting
+the existing @value{GDBN} CLI), those clients must co-operate when
+controlling @code{libgdb}. In particular, a client must ensure that
+@code{libgdb} is idle (i.e. no other client is using @code{libgdb})
+before responding to a @file{gdb-event} by making a query.
+@section CLI support
-@node Symbol Reading
-@chapter Symbol Reading
+At present @value{GDBN}'s CLI is very much entangled in with the core of
+@code{libgdb}. Consequently, a client wishing to include the CLI in
+their interface needs to carefully co-ordinate its own and the CLI's
+requirements.
-GDB reads symbols from "symbol files". The usual symbol file is the
-file containing the program which gdb is debugging. GDB can be directed
-to use a different file for symbols (with the ``symbol-file''
-command), and it can also read more symbols via the ``add-file'' and ``load''
-commands, or while reading symbols from shared libraries.
+It is suggested that the client set @code{libgdb} up to be bi-modal
+(alternate between CLI and client query modes). The notes below sketch
+out the theory:
-Symbol files are initially opened by @file{symfile.c} using the BFD
-library. BFD identifies the type of the file by examining its header.
-@code{symfile_init} then uses this identification to locate a
-set of symbol-reading functions.
+@itemize @bullet
+@item
+The client registers itself as an observer of @code{libgdb}.
+@item
+The client create and install @code{cli-out} builder using its own
+versions of the @code{ui-file} @code{gdb_stderr}, @code{gdb_stdtarg} and
+@code{gdb_stdout} streams.
+@item
+The client creates a separate custom @code{ui-out} builder that is only
+used while making direct queries to @code{libgdb}.
+@end itemize
-Symbol reading modules identify themselves to GDB by calling
+When the client receives input intended for the CLI, it simply passes it
+along. Since the @code{cli-out} builder is installed by default, all
+the CLI output in response to that command is routed (pronounced rooted)
+through to the client controlled @code{gdb_stdout} et.@: al.@: streams.
+At the same time, the client is kept abreast of internal changes by
+virtue of being a @code{libgdb} observer.
+
+The only restriction on the client is that it must wait until
+@code{libgdb} becomes idle before initiating any queries (using the
+client's custom builder).
+
+@section @code{libgdb} components
+
+@subheading Observer - @file{gdb-events.h}
+@file{gdb-events} provides the client with a very raw mechanism that can
+be used to implement an observer. At present it only allows for one
+observer and that observer must, internally, handle the need to delay
+the processing of any event notifications until after @code{libgdb} has
+finished the current command.
+
+@subheading Builder - @file{ui-out.h}
+@file{ui-out} provides the infrastructure necessary for a client to
+create a builder. That builder is then passed down to @code{libgdb}
+when doing any queries.
+
+@subheading Event Loop - @file{event-loop.h}
+@c There could be an entire section on the event-loop
+@file{event-loop}, currently non-re-entrant, provides a simple event
+loop. A client would need to either plug its self into this loop or,
+implement a new event-loop that GDB would use.
+
+The event-loop will eventually be made re-entrant. This is so that
+@value{GDB} can better handle the problem of some commands blocking
+instead of returning.
+
+@subheading Library - @file{gdb.h}
+@file{libgdb} is the most obvious component of this system. It provides
+the query interface. Each function is parameterized by a @code{ui-out}
+builder. The result of the query is constructed using that builder
+before the query function returns.
+
+@node Symbol Handling
+
+@chapter Symbol Handling
+
+Symbols are a key part of @value{GDBN}'s operation. Symbols include variables,
+functions, and types.
+
+@section Symbol Reading
+
+@cindex symbol reading
+@cindex reading of symbols
+@cindex symbol files
+@value{GDBN} reads symbols from @dfn{symbol files}. The usual symbol
+file is the file containing the program which @value{GDBN} is
+debugging. @value{GDBN} can be directed to use a different file for
+symbols (with the @samp{symbol-file} command), and it can also read
+more symbols via the @samp{add-file} and @samp{load} commands, or while
+reading symbols from shared libraries.
+
+@findex find_sym_fns
+Symbol files are initially opened by code in @file{symfile.c} using
+the BFD library (@pxref{Support Libraries}). BFD identifies the type
+of the file by examining its header. @code{find_sym_fns} then uses
+this identification to locate a set of symbol-reading functions.
+
+@findex add_symtab_fns
+@cindex @code{sym_fns} structure
+@cindex adding a symbol-reading module
+Symbol-reading modules identify themselves to @value{GDBN} by calling
@code{add_symtab_fns} during their module initialization. The argument
-to @code{add_symtab_fns} is a @code{struct sym_fns} which contains
-the name (or name prefix) of the symbol format, the length of the prefix,
+to @code{add_symtab_fns} is a @code{struct sym_fns} which contains the
+name (or name prefix) of the symbol format, the length of the prefix,
and pointers to four functions. These functions are called at various
-times to process symbol-files whose identification matches the specified
+times to process symbol files whose identification matches the specified
prefix.
The functions supplied by each module are:
@table @code
-@item @var{xxx}_symfile_init(struct sym_fns *sf)
+@item @var{xyz}_symfile_init(struct sym_fns *sf)
+@cindex secondary symbol file
Called from @code{symbol_file_add} when we are about to read a new
-symbol file. This function should clean up any internal state
-(possibly resulting from half-read previous files, for example)
-and prepare to read a new symbol file. Note that the symbol file
-which we are reading might be a new "main" symbol file, or might
-be a secondary symbol file whose symbols are being added to the
-existing symbol table.
-
-The argument to @code{@var{xxx}_symfile_init} is a newly allocated
-@code{struct sym_fns} whose @code{bfd} field contains the BFD
-for the new symbol file being read. Its @code{private} field
-has been zeroed, and can be modified as desired. Typically,
-a struct of private information will be @code{malloc}'d, and
-a pointer to it will be placed in the @code{private} field.
-
-There is no result from @code{@var{xxx}_symfile_init}, but it can call
+symbol file. This function should clean up any internal state (possibly
+resulting from half-read previous files, for example) and prepare to
+read a new symbol file. Note that the symbol file which we are reading
+might be a new ``main'' symbol file, or might be a secondary symbol file
+whose symbols are being added to the existing symbol table.
+
+The argument to @code{@var{xyz}_symfile_init} is a newly allocated
+@code{struct sym_fns} whose @code{bfd} field contains the BFD for the
+new symbol file being read. Its @code{private} field has been zeroed,
+and can be modified as desired. Typically, a struct of private
+information will be @code{malloc}'d, and a pointer to it will be placed
+in the @code{private} field.
+
+There is no result from @code{@var{xyz}_symfile_init}, but it can call
@code{error} if it detects an unavoidable problem.
-@item @var{xxx}_new_init()
+@item @var{xyz}_new_init()
Called from @code{symbol_file_add} when discarding existing symbols.
-This function need only handle
-the symbol-reading module's internal state; the symbol table data
-structures visible to the rest of GDB will be discarded by
-@code{symbol_file_add}. It has no arguments and no result.
-It may be called after @code{@var{xxx}_symfile_init}, if a new symbol
-table is being read, or may be called alone if all symbols are
-simply being discarded.
+This function needs only handle the symbol-reading module's internal
+state; the symbol table data structures visible to the rest of
+@value{GDBN} will be discarded by @code{symbol_file_add}. It has no
+arguments and no result. It may be called after
+@code{@var{xyz}_symfile_init}, if a new symbol table is being read, or
+may be called alone if all symbols are simply being discarded.
-@item @var{xxx}_symfile_read(struct sym_fns *sf, CORE_ADDR addr, int mainline)
+@item @var{xyz}_symfile_read(struct sym_fns *sf, CORE_ADDR addr, int mainline)
Called from @code{symbol_file_add} to actually read the symbols from a
symbol-file into a set of psymtabs or symtabs.
-@code{sf} points to the struct sym_fns originally passed to
-@code{@var{xxx}_sym_init} for possible initialization. @code{addr} is the
-offset between the file's specified start address and its true address
-in memory. @code{mainline} is 1 if this is the main symbol table being
-read, and 0 if a secondary symbol file (e.g. shared library or
-dynamically loaded file) is being read.@refill
+@code{sf} points to the @code{struct sym_fns} originally passed to
+@code{@var{xyz}_sym_init} for possible initialization. @code{addr} is
+the offset between the file's specified start address and its true
+address in memory. @code{mainline} is 1 if this is the main symbol
+table being read, and 0 if a secondary symbol file (e.g. shared library
+or dynamically loaded file) is being read.@refill
@end table
In addition, if a symbol-reading module creates psymtabs when
-@var{xxx}_symfile_read is called, these psymtabs will contain a pointer to
-a function @code{@var{xxx}_psymtab_to_symtab}, which can be called from
-any point in the GDB symbol-handling code.
+@var{xyz}_symfile_read is called, these psymtabs will contain a pointer
+to a function @code{@var{xyz}_psymtab_to_symtab}, which can be called
+from any point in the @value{GDBN} symbol-handling code.
@table @code
-@item @var{xxx}_psymtab_to_symtab (struct partial_symtab *pst)
-
-Called from @code{psymtab_to_symtab} (or the PSYMTAB_TO_SYMTAB
-macro) if the psymtab has not already been read in and had its
-@code{pst->symtab} pointer set. The argument is the psymtab
-to be fleshed-out into a symtab. Upon return, pst->readin
-should have been set to 1, and pst->symtab should contain a
-pointer to the new corresponding symtab, or zero if there
-were no symbols in that part of the symbol file.
+@item @var{xyz}_psymtab_to_symtab (struct partial_symtab *pst)
+
+Called from @code{psymtab_to_symtab} (or the @code{PSYMTAB_TO_SYMTAB} macro) if
+the psymtab has not already been read in and had its @code{pst->symtab}
+pointer set. The argument is the psymtab to be fleshed-out into a
+symtab. Upon return, @code{pst->readin} should have been set to 1, and
+@code{pst->symtab} should contain a pointer to the new corresponding symtab, or
+zero if there were no symbols in that part of the symbol file.
@end table
+@section Partial Symbol Tables
-@node Cleanups
-@chapter Cleanups
+@value{GDBN} has three types of symbol tables:
-Cleanups are a structured way to deal with things that need to be done
-later. When your code does something (like @code{malloc} some memory, or open
-a file) that needs to be undone later (e.g. free the memory or close
-the file), it can make a cleanup. The cleanup will be done at some
-future point: when the command is finished, when an error occurs, or
-when your code decides it's time to do cleanups.
+@itemize @bullet
+@cindex full symbol table
+@cindex symtabs
+@item
+Full symbol tables (@dfn{symtabs}). These contain the main
+information about symbols and addresses.
-You can also discard cleanups, that is, throw them away without doing
-what they say. This is only done if you ask that it be done.
+@cindex psymtabs
+@item
+Partial symbol tables (@dfn{psymtabs}). These contain enough
+information to know when to read the corresponding part of the full
+symbol table.
-Syntax:
+@cindex minimal symbol table
+@cindex minsymtabs
+@item
+Minimal symbol tables (@dfn{msymtabs}). These contain information
+gleaned from non-debugging symbols.
+@end itemize
-@table @code
-@item struct cleanup *@var{old_chain};
-Declare a variable which will hold a cleanup chain handle.
+@cindex partial symbol table
+This section describes partial symbol tables.
-@item @var{old_chain} = make_cleanup (@var{function}, @var{arg});
-Make a cleanup which will cause @var{function} to be called with @var{arg}
-(a @code{char *}) later. The result, @var{old_chain}, is a handle that can be
-passed to @code{do_cleanups} or @code{discard_cleanups} later. Unless you are
-going to call @code{do_cleanups} or @code{discard_cleanups} yourself,
-you can ignore the result from @code{make_cleanup}.
+A psymtab is constructed by doing a very quick pass over an executable
+file's debugging information. Small amounts of information are
+extracted---enough to identify which parts of the symbol table will
+need to be re-read and fully digested later, when the user needs the
+information. The speed of this pass causes @value{GDBN} to start up very
+quickly. Later, as the detailed rereading occurs, it occurs in small
+pieces, at various times, and the delay therefrom is mostly invisible to
+the user.
+@c (@xref{Symbol Reading}.)
+The symbols that show up in a file's psymtab should be, roughly, those
+visible to the debugger's user when the program is not running code from
+that file. These include external symbols and types, static symbols and
+types, and @code{enum} values declared at file scope.
-@item do_cleanups (@var{old_chain});
-Perform all cleanups done since @code{make_cleanup} returned @var{old_chain}.
-E.g.:
-@example
-make_cleanup (a, 0);
-old = make_cleanup (b, 0);
-do_cleanups (old);
-@end example
-@noindent
-will call @code{b()} but will not call @code{a()}. The cleanup that calls @code{a()} will remain
-in the cleanup chain, and will be done later unless otherwise discarded.@refill
+The psymtab also contains the range of instruction addresses that the
+full symbol table would represent.
-@item discard_cleanups (@var{old_chain});
-Same as @code{do_cleanups} except that it just removes the cleanups from the
-chain and does not call the specified functions.
+@cindex finding a symbol
+@cindex symbol lookup
+The idea is that there are only two ways for the user (or much of the
+code in the debugger) to reference a symbol:
-@end table
+@itemize @bullet
+@findex find_pc_function
+@findex find_pc_line
+@item
+By its address (e.g. execution stops at some address which is inside a
+function in this file). The address will be noticed to be in the
+range of this psymtab, and the full symtab will be read in.
+@code{find_pc_function}, @code{find_pc_line}, and other
+@code{find_pc_@dots{}} functions handle this.
-Some functions, e.g. @code{fputs_filtered()} or @code{error()}, specify that they
-``should not be called when cleanups are not in place''. This means
-that any actions you need to reverse in the case of an error or
-interruption must be on the cleanup chain before you call these functions,
-since they might never return to your code (they @samp{longjmp} instead).
+@cindex lookup_symbol
+@item
+By its name
+(e.g. the user asks to print a variable, or set a breakpoint on a
+function). Global names and file-scope names will be found in the
+psymtab, which will cause the symtab to be pulled in. Local names will
+have to be qualified by a global name, or a file-scope name, in which
+case we will have already read in the symtab as we evaluated the
+qualifier. Or, a local symbol can be referenced when we are ``in'' a
+local scope, in which case the first case applies. @code{lookup_symbol}
+does most of the work here.
+@end itemize
+The only reason that psymtabs exist is to cause a symtab to be read in
+at the right moment. Any symbol that can be elided from a psymtab,
+while still causing that to happen, should not appear in it. Since
+psymtabs don't have the idea of scope, you can't put local symbols in
+them anyway. Psymtabs don't have the idea of the type of a symbol,
+either, so types need not appear, unless they will be referenced by
+name.
-@node Wrapping
-@chapter Wrapping Output Lines
+It is a bug for @value{GDBN} to behave one way when only a psymtab has
+been read, and another way if the corresponding symtab has been read
+in. Such bugs are typically caused by a psymtab that does not contain
+all the visible symbols, or which has the wrong instruction address
+ranges.
+
+The psymtab for a particular section of a symbol file (objfile) could be
+thrown away after the symtab has been read in. The symtab should always
+be searched before the psymtab, so the psymtab will never be used (in a
+bug-free environment). Currently, psymtabs are allocated on an obstack,
+and all the psymbols themselves are allocated in a pair of large arrays
+on an obstack, so there is little to be gained by trying to free them
+unless you want to do a lot more work.
+
+@section Types
+
+@unnumberedsubsec Fundamental Types (e.g., @code{FT_VOID}, @code{FT_BOOLEAN}).
+
+@cindex fundamental types
+These are the fundamental types that @value{GDBN} uses internally. Fundamental
+types from the various debugging formats (stabs, ELF, etc) are mapped
+into one of these. They are basically a union of all fundamental types
+that @value{GDBN} knows about for all the languages that @value{GDBN}
+knows about.
+
+@unnumberedsubsec Type Codes (e.g., @code{TYPE_CODE_PTR}, @code{TYPE_CODE_ARRAY}).
+
+@cindex type codes
+Each time @value{GDBN} builds an internal type, it marks it with one
+of these types. The type may be a fundamental type, such as
+@code{TYPE_CODE_INT}, or a derived type, such as @code{TYPE_CODE_PTR}
+which is a pointer to another type. Typically, several @code{FT_*}
+types map to one @code{TYPE_CODE_*} type, and are distinguished by
+other members of the type struct, such as whether the type is signed
+or unsigned, and how many bits it uses.
+
+@unnumberedsubsec Builtin Types (e.g., @code{builtin_type_void}, @code{builtin_type_char}).
+
+These are instances of type structs that roughly correspond to
+fundamental types and are created as global types for @value{GDBN} to
+use for various ugly historical reasons. We eventually want to
+eliminate these. Note for example that @code{builtin_type_int}
+initialized in @file{gdbtypes.c} is basically the same as a
+@code{TYPE_CODE_INT} type that is initialized in @file{c-lang.c} for
+an @code{FT_INTEGER} fundamental type. The difference is that the
+@code{builtin_type} is not associated with any particular objfile, and
+only one instance exists, while @file{c-lang.c} builds as many
+@code{TYPE_CODE_INT} types as needed, with each one associated with
+some particular objfile.
+
+@section Object File Formats
+@cindex object file formats
+
+@subsection a.out
+
+@cindex @code{a.out} format
+The @code{a.out} format is the original file format for Unix. It
+consists of three sections: @code{text}, @code{data}, and @code{bss},
+which are for program code, initialized data, and uninitialized data,
+respectively.
+
+The @code{a.out} format is so simple that it doesn't have any reserved
+place for debugging information. (Hey, the original Unix hackers used
+@samp{adb}, which is a machine-language debugger!) The only debugging
+format for @code{a.out} is stabs, which is encoded as a set of normal
+symbols with distinctive attributes.
+
+The basic @code{a.out} reader is in @file{dbxread.c}.
+
+@subsection COFF
+
+@cindex COFF format
+The COFF format was introduced with System V Release 3 (SVR3) Unix.
+COFF files may have multiple sections, each prefixed by a header. The
+number of sections is limited.
+
+The COFF specification includes support for debugging. Although this
+was a step forward, the debugging information was woefully limited. For
+instance, it was not possible to represent code that came from an
+included file.
+
+The COFF reader is in @file{coffread.c}.
+
+@subsection ECOFF
+
+@cindex ECOFF format
+ECOFF is an extended COFF originally introduced for Mips and Alpha
+workstations.
+
+The basic ECOFF reader is in @file{mipsread.c}.
+
+@subsection XCOFF
+
+@cindex XCOFF format
+The IBM RS/6000 running AIX uses an object file format called XCOFF.
+The COFF sections, symbols, and line numbers are used, but debugging
+symbols are @code{dbx}-style stabs whose strings are located in the
+@code{.debug} section (rather than the string table). For more
+information, see @ref{Top,,,stabs,The Stabs Debugging Format}.
-Output that goes through @code{printf_filtered} or @code{fputs_filtered} or
-@code{fputs_demangled} needs only to have calls to @code{wrap_here} added
-in places that would be good breaking points. The utility routines
-will take care of actually wrapping if the line width is exceeded.
+The shared library scheme has a clean interface for figuring out what
+shared libraries are in use, but the catch is that everything which
+refers to addresses (symbol tables and breakpoints at least) needs to be
+relocated for both shared libraries and the main executable. At least
+using the standard mechanism this can only be done once the program has
+been run (or the core file has been read).
-The argument to @code{wrap_here} is an indentation string which is printed
-@emph{only} if the line breaks there. This argument is saved away and used
-later. It must remain valid until the next call to @code{wrap_here} or
-until a newline has been printed through the @code{*_filtered} functions.
-Don't pass in a local variable and then return!
+@subsection PE
-It is usually best to call @code{wrap_here()} after printing a comma or space.
-If you call it before printing a space, make sure that your indentation
-properly accounts for the leading space that will print if the line wraps
-there.
+@cindex PE-COFF format
+Windows 95 and NT use the PE (@dfn{Portable Executable}) format for their
+executables. PE is basically COFF with additional headers.
-Any function or set of functions that produce filtered output must finish
-by printing a newline, to flush the wrap buffer, before switching to
-unfiltered (``@code{printf}'') output. Symbol reading routines that print
-warnings are a good example.
+While BFD includes special PE support, @value{GDBN} needs only the basic
+COFF reader.
+@subsection ELF
-@node Frames
-@chapter Frames
+@cindex ELF format
+The ELF format came with System V Release 4 (SVR4) Unix. ELF is similar
+to COFF in being organized into a number of sections, but it removes
+many of COFF's limitations.
-A frame is a construct that GDB uses to keep track of calling and called
-functions.
+The basic ELF reader is in @file{elfread.c}.
-@table @code
-@item FRAME_FP
-in the machine description has no meaning to the machine-independent
-part of GDB, except that it is used when setting up a new frame from
-scratch, as follows:
+@subsection SOM
-@example
- create_new_frame (read_register (FP_REGNUM), read_pc ()));
-@end example
+@cindex SOM format
+SOM is HP's object file and debug format (not to be confused with IBM's
+SOM, which is a cross-language ABI).
-Other than that, all the meaning imparted to @code{FP_REGNUM} is imparted by
-the machine-dependent code. So, @code{FP_REGNUM} can have any value that
-is convenient for the code that creates new frames. (@code{create_new_frame}
-calls @code{INIT_EXTRA_FRAME_INFO} if it is defined; that is where you should
-use the @code{FP_REGNUM} value, if your frames are nonstandard.)
-
-@item FRAME_CHAIN
-Given a GDB frame, determine the address of the calling function's
-frame. This will be used to create a new GDB frame struct, and then
-@code{INIT_EXTRA_FRAME_INFO} and @code{INIT_FRAME_PC} will be called for
-the new frame.
-@end table
+The SOM reader is in @file{hpread.c}.
-@node Remote Stubs
-@chapter Remote Stubs
+@subsection Other File Formats
-GDB's file @file{remote.c} talks a serial protocol to code that runs
-in the target system. GDB provides several sample ``stubs'' that can
-be integrated into target programs or operating systems for this purpose;
-they are named @file{*-stub.c}.
+@cindex Netware Loadable Module format
+Other file formats that have been supported by @value{GDBN} include Netware
+Loadable Modules (@file{nlmread.c}).
-The GDB user's manual describes how to put such a stub into your target
-code. What follows is a discussion of integrating the SPARC stub
-into a complicated operating system (rather than a simple program),
-by Stu Grossman, the author of this stub.
+@section Debugging File Formats
-The trap handling code in the stub assumes the following upon entry to
-trap_low:
+This section describes characteristics of debugging information that
+are independent of the object file format.
-@enumerate
-@item %l1 and %l2 contain pc and npc respectively at the time of the trap
-@item traps are disabled
-@item you are in the correct trap window
-@end enumerate
+@subsection stabs
-As long as your trap handler can guarantee those conditions, then there is no
-reason why you shouldn't be able to `share' traps with the stub. The stub has
-no requirement that it be jumped to directly from the hardware trap vector.
-That is why it calls @code{exceptionHandler()}, which is provided by the external
-environment. For instance, this could setup the hardware traps to actually
-execute code which calls the stub first, and then transfers to its own trap
-handler.
-
-For the most point, there probably won't be much of an issue with `sharing'
-traps, as the traps we use are usually not used by the kernel, and often
-indicate unrecoverable error conditions. Anyway, this is all controlled by a
-table, and is trivial to modify.
-The most important trap for us is for @code{ta 1}. Without that, we
-can't single step or do breakpoints. Everything else is unnecessary
-for the proper operation of the debugger/stub.
-
-From reading the stub, it's probably not obvious how breakpoints work. They
-are simply done by deposit/examine operations from GDB.
-
-@node Longjmp Support
-@chapter Longjmp Support
-
-GDB has support for figuring out that the target is doing a
-@code{longjmp} and for stopping at the target of the jump, if we are
-stepping. This is done with a few specialized internal breakpoints,
-which are visible in the @code{maint info breakpoint} command.
+@cindex stabs debugging info
+@code{stabs} started out as special symbols within the @code{a.out}
+format. Since then, it has been encapsulated into other file
+formats, such as COFF and ELF.
-To make this work, you need to define a macro called
-@code{GET_LONGJMP_TARGET}, which will examine the @code{jmp_buf}
-structure and extract the longjmp target address. Since @code{jmp_buf}
-is target specific, you will need to define it in the appropriate
-@file{tm-xxx.h} file. Look in @file{tm-sun4os4.h} and
-@file{sparc-tdep.c} for examples of how to do this.
+While @file{dbxread.c} does some of the basic stab processing,
+including for encapsulated versions, @file{stabsread.c} does
+the real work.
-@node Coding Style
-@chapter Coding Style
-
-GDB is generally written using the GNU coding standards, as described in
-@file{standards.texi}, which is available for anonymous FTP from GNU
-archive sites. There are some additional considerations for GDB
-maintainers that reflect the unique environment and style of GDB
-maintenance. If you follow these guidelines, GDB will be more
-consistent and easier to maintain.
-
-GDB's policy on the use of prototypes is that prototypes are used
-to @emph{declare} functions but never to @emph{define} them. Simple
-macros are used in the declarations, so that a non-ANSI compiler can
-compile GDB without trouble. The simple macro calls are used like
-this:
-
-@example @code
-extern int
-memory_remove_breakpoint PARAMS ((CORE_ADDR, char *));
-@end example
+@subsection COFF
-Note the double parentheses around the parameter types. This allows
-an arbitrary number of parameters to be described, without freaking
-out the C preprocessor. When the function has no parameters, it
-should be described like:
+@cindex COFF debugging info
+The basic COFF definition includes debugging information. The level
+of support is minimal and non-extensible, and is not often used.
-@example @code
-void
-noprocess PARAMS ((void));
-@end example
+@subsection Mips debug (Third Eye)
-The @code{PARAMS} macro expands to its argument in ANSI C, or to a simple
-@code{()} in traditional C.
+@cindex ECOFF debugging info
+ECOFF includes a definition of a special debug format.
-All external functions should have a @code{PARAMS} declaration in a
-header file that callers include. All static functions should have such
-a declaration near the top of their source file.
+The file @file{mdebugread.c} implements reading for this format.
-We don't have a gcc option that will properly check that these rules
-have been followed, but it's GDB policy, and we periodically check it
-using the tools available (plus manual labor), and clean up any remnants.
+@subsection DWARF 1
-@node Clean Design
-@chapter Clean Design
+@cindex DWARF 1 debugging info
+DWARF 1 is a debugging format that was originally designed to be
+used with ELF in SVR4 systems.
-In addition to getting the syntax right, there's the little question of
-semantics. Some things are done in certain ways in GDB because long
-experience has shown that the more obvious ways caused various kinds of
-trouble. In particular:
+@c CHILL_PRODUCER
+@c GCC_PRODUCER
+@c GPLUS_PRODUCER
+@c LCC_PRODUCER
+@c If defined, these are the producer strings in a DWARF 1 file. All of
+@c these have reasonable defaults already.
-@table @bullet
-@item
-You can't assume the byte order of anything that comes from a
-target (including @var{value}s, object files, and instructions). Such
-things must be byte-swapped using @code{SWAP_TARGET_AND_HOST} in GDB,
-or one of the swap routines defined in @file{bfd.h}, such as @code{bfd_get_32}.
+The DWARF 1 reader is in @file{dwarfread.c}.
-@item
-You can't assume that you know what interface is being used to talk to
-the target system. All references to the target must go through the
-current @code{target_ops} vector.
+@subsection DWARF 2
-@item
-You can't assume that the host and target machines are the same machine
-(except in the ``native'' support modules).
-In particular, you can't assume that the target machine's header files
-will be available on the host machine. Target code must bring along its
-own header files -- written from scratch or explicitly donated by their
-owner, to avoid copyright problems.
+@cindex DWARF 2 debugging info
+DWARF 2 is an improved but incompatible version of DWARF 1.
-@item
-Insertion of new @code{#ifdef}'s will be frowned upon. It's much better
-to write the code portably than to conditionalize it for various systems.
+The DWARF 2 reader is in @file{dwarf2read.c}.
-@item
-New @code{#ifdef}'s which test for specific compilers or manufacturers
-or operating systems are unacceptable. All @code{#ifdef}'s should test
-for features. The information about which configurations contain which
-features should be segregated into the configuration files. Experience
-has proven far too often that a feature unique to one particular system
-often creeps into other systems; and that a conditional based on
-some predefined macro for your current system will become worthless
-over time, as new versions of your system come out that behave differently
-with regard to this feature.
+@subsection SOM
-@item
-Adding code that handles specific architectures, operating systems, target
-interfaces, or hosts, is not acceptable in generic code. If a hook
-is needed at that point, invent a generic hook and define it for your
-configuration, with something like:
+@cindex SOM debugging info
+Like COFF, the SOM definition includes debugging information.
-@example
-#ifdef WRANGLE_SIGNALS
- WRANGLE_SIGNALS (signo);
-#endif
-@end example
+@section Adding a New Symbol Reader to @value{GDBN}
-In your host, target, or native configuration file, as appropriate,
-define @code{WRANGLE_SIGNALS} to do the machine-dependent thing. Take
-a bit of care in defining the hook, so that it can be used by other
-ports in the future, if they need a hook in the same place.
+@cindex adding debugging info reader
+If you are using an existing object file format (@code{a.out}, COFF, ELF, etc),
+there is probably little to be done.
-If the hook is not defined, the code should do whatever "most" machines
-want. Using @code{#ifdef}, as above, is the preferred way to do this,
-but sometimes that gets convoluted, in which case use
+If you need to add a new object file format, you must first add it to
+BFD. This is beyond the scope of this document.
-@example
-#ifndef SPECIAL_FOO_HANDLING
-#define SPECIAL_FOO_HANDLING(pc, sp) (0)
-#endif
-@end example
+You must then arrange for the BFD code to provide access to the
+debugging symbols. Generally @value{GDBN} will have to call swapping routines
+from BFD and a few other BFD internal routines to locate the debugging
+information. As much as possible, @value{GDBN} should not depend on the BFD
+internal data structures.
-where the macro is used or in an appropriate header file.
-
-Whether to include a @dfn{small} hook, a hook around the exact pieces of
-code which are system-dependent, or whether to replace a whole function
-with a hook depends on the case. A good example of this dilemma can be
-found in @code{get_saved_register}. All machines that GDB 2.8 ran on
-just needed the @code{FRAME_FIND_SAVED_REGS} hook to find the saved
-registers. Then the SPARC and Pyramid came along, and
-@code{HAVE_REGISTER_WINDOWS} and @code{REGISTER_IN_WINDOW_P} were
-introduced. Then the 29k and 88k required the @code{GET_SAVED_REGISTER}
-hook. The first three are examples of small hooks; the latter replaces
-a whole function. In this specific case, it is useful to have both
-kinds; it would be a bad idea to replace all the uses of the small hooks
-with @code{GET_SAVED_REGISTER}, since that would result in much
-duplicated code. Other times, duplicating a few lines of code here or
-there is much cleaner than introducing a large number of small hooks.
-
-Another way to generalize GDB along a particular interface is with an
-attribute struct. For example, GDB has been generalized to handle
-multiple kinds of remote interfaces -- not by #ifdef's everywhere, but
-by defining the "target_ops" structure and having a current target (as
-well as a stack of targets below it, for memory references). Whenever
-something needs to be done that depends on which remote interface we are
-using, a flag in the current target_ops structure is tested (e.g.
-`target_has_stack'), or a function is called through a pointer in the
-current target_ops structure. In this way, when a new remote interface
-is added, only one module needs to be touched -- the one that actually
-implements the new remote interface. Other examples of
-attribute-structs are BFD access to multiple kinds of object file
-formats, or GDB's access to multiple source languages.
+For some targets (e.g., COFF), there is a special transfer vector used
+to call swapping routines, since the external data structures on various
+platforms have different sizes and layouts. Specialized routines that
+will only ever be implemented by one object file format may be called
+directly. This interface should be described in a file
+@file{bfd/lib@var{xyz}.h}, which is included by @value{GDBN}.
-Please avoid duplicating code. For example, in GDB 3.x all the code
-interfacing between @code{ptrace} and the rest of GDB was duplicated in
-@file{*-dep.c}, and so changing something was very painful. In GDB 4.x,
-these have all been consolidated into @file{infptrace.c}.
-@file{infptrace.c} can deal with variations between systems the same way
-any system-independent file would (hooks, #if defined, etc.), and
-machines which are radically different don't need to use infptrace.c at
-all.
-@item
-@emph{Do} write code that doesn't depend on the sizes of C data types,
-the format of the host's floating point numbers, the alignment of anything,
-or the order of evaluation of expressions. In short, follow good
-programming practices for writing portable C code.
+@node Language Support
-@end table
+@chapter Language Support
-@node Submitting Patches
-@chapter Submitting Patches
+@cindex language support
+@value{GDBN}'s language support is mainly driven by the symbol reader,
+although it is possible for the user to set the source language
+manually.
-Thanks for thinking of offering your changes back to the community of
-GDB users. In general we like to get well designed enhancements.
-Thanks also for checking in advance about the best way to transfer the
-changes.
+@value{GDBN} chooses the source language by looking at the extension
+of the file recorded in the debug info; @file{.c} means C, @file{.f}
+means Fortran, etc. It may also use a special-purpose language
+identifier if the debug format supports it, like with DWARF.
-The two main problems with getting your patches in are,
+@section Adding a Source Language to @value{GDBN}
-@table @bullet
-@item
-The GDB maintainers will only install ``cleanly designed'' patches.
-You may not always agree on what is clean design.
-@pxref{Coding Style}, @pxref{Clean Design}.
+@cindex adding source language
+To add other languages to @value{GDBN}'s expression parser, follow the
+following steps:
-@item
-If the maintainers don't have time to put the patch in when it
-arrives, or if there is any question about a patch, it
-goes into a large queue with everyone else's patches and
-bug reports.
-@end table
+@table @emph
+@item Create the expression parser.
-I don't know how to get past these problems except by continuing to try.
+@cindex expression parser
+This should reside in a file @file{@var{lang}-exp.y}. Routines for
+building parsed expressions into a @code{union exp_element} list are in
+@file{parse.c}.
-There are two issues here -- technical and legal.
+@cindex language parser
+Since we can't depend upon everyone having Bison, and YACC produces
+parsers that define a bunch of global names, the following lines
+@strong{must} be included at the top of the YACC parser, to prevent the
+various parsers from defining the same global names:
-The legal issue is that to incorporate substantial changes requires a
-copyright assignment from you and/or your employer, granting ownership
-of the changes to the Free Software Foundation. You can get the
-standard document for doing this by sending mail to
-@code{gnu@@prep.ai.mit.edu} and asking for it. I recommend that people
-write in "All programs owned by the Free Software Foundation" as "NAME
-OF PROGRAM", so that changes in many programs (not just GDB, but GAS,
-Emacs, GCC, etc) can be contributed with only one piece of legalese
-pushed through the bureacracy and filed with the FSF. I can't start
-merging changes until this paperwork is received by the FSF (their
-rules, which I follow since I maintain it for them).
+@example
+#define yyparse @var{lang}_parse
+#define yylex @var{lang}_lex
+#define yyerror @var{lang}_error
+#define yylval @var{lang}_lval
+#define yychar @var{lang}_char
+#define yydebug @var{lang}_debug
+#define yypact @var{lang}_pact
+#define yyr1 @var{lang}_r1
+#define yyr2 @var{lang}_r2
+#define yydef @var{lang}_def
+#define yychk @var{lang}_chk
+#define yypgo @var{lang}_pgo
+#define yyact @var{lang}_act
+#define yyexca @var{lang}_exca
+#define yyerrflag @var{lang}_errflag
+#define yynerrs @var{lang}_nerrs
+@end example
-Technically, the easiest way to receive changes is to receive each
-feature as a small context diff or unidiff, suitable for "patch".
-Each message sent to me should include the changes to C code and
-header files for a single feature, plus ChangeLog entries for each
-directory where files were modified, and diffs for any changes needed
-to the manuals (gdb/doc/gdb.texi or gdb/doc/gdbint.texi). If there
-are a lot of changes for a single feature, they can be split down
-into multiple messages.
+At the bottom of your parser, define a @code{struct language_defn} and
+initialize it with the right values for your language. Define an
+@code{initialize_@var{lang}} routine and have it call
+@samp{add_language(@var{lang}_language_defn)} to tell the rest of @value{GDBN}
+that your language exists. You'll need some other supporting variables
+and functions, which will be used via pointers from your
+@code{@var{lang}_language_defn}. See the declaration of @code{struct
+language_defn} in @file{language.h}, and the other @file{*-exp.y} files,
+for more information.
-In this way, if I read and like the feature, I can add it to the
-sources with a single patch command, do some testing, and check it in.
-If you leave out the ChangeLog, I have to write one. If you leave
-out the doc, I have to puzzle out what needs documenting. Etc.
+@item Add any evaluation routines, if necessary
-The reason to send each change in a separate message is that I will
-not install some of the changes. They'll be returned to you with
-questions or comments. If I'm doing my job, my message back to you
-will say what you have to fix in order to make the change acceptable.
-The reason to have separate messages for separate features is so
-that other changes (which I @emph{am} willing to accept) can be installed
-while one or more changes are being reworked. If multiple features
-are sent in a single message, I tend to not put in the effort to sort
-out the acceptable changes from the unacceptable, so none of the
-features get installed until all are acceptable.
-
-If this sounds painful or authoritarian, well, it is. But I get a lot
-of bug reports and a lot of patches, and most of them don't get
-installed because I don't have the time to finish the job that the bug
-reporter or the contributor could have done. Patches that arrive
-complete, working, and well designed, tend to get installed on the day
-they arrive. The others go into a queue and get installed if and when
-I scan back over the queue -- which can literally take months
-sometimes. It's in both our interests to make patch installation easy
--- you get your changes installed, and I make some forward progress on
-GDB in a normal 12-hour day (instead of them having to wait until I
-have a 14-hour or 16-hour day to spend cleaning up patches before I
-can install them).
-
-Please send patches to @code{bug-gdb@@prep.ai.mit.edu}, if they are less
-than about 25,000 characters. If longer than that, either make them
-available somehow (e.g. anonymous FTP), and announce it on
-@code{bug-gdb}, or send them directly to the GDB maintainers at
-@code{gdb-patches@@cygnus.com}.
-
-@node Host Conditionals
-@chapter Host Conditionals
-
-When GDB is configured and compiled, various macros are defined or left
-undefined, to control compilation based on the attributes of the host
-system. These macros and their meanings are:
-
-@emph{NOTE: For now, both host and target conditionals are here.
-Eliminate target conditionals from this list as they are identified.}
+@cindex expression evaluation routines
+@findex evaluate_subexp
+@findex prefixify_subexp
+@findex length_of_subexp
+If you need new opcodes (that represent the operations of the language),
+add them to the enumerated type in @file{expression.h}. Add support
+code for these operations in the @code{evaluate_subexp} function
+defined in the file @file{eval.c}. Add cases
+for new opcodes in two functions from @file{parse.c}:
+@code{prefixify_subexp} and @code{length_of_subexp}. These compute
+the number of @code{exp_element}s that a given operation takes up.
+
+@item Update some existing code
+
+Add an enumerated identifier for your language to the enumerated type
+@code{enum language} in @file{defs.h}.
+
+Update the routines in @file{language.c} so your language is included.
+These routines include type predicates and such, which (in some cases)
+are language dependent. If your language does not appear in the switch
+statement, an error is reported.
+
+@vindex current_language
+Also included in @file{language.c} is the code that updates the variable
+@code{current_language}, and the routines that translate the
+@code{language_@var{lang}} enumerated identifier into a printable
+string.
+
+@findex _initialize_language
+Update the function @code{_initialize_language} to include your
+language. This function picks the default language upon startup, so is
+dependent upon which languages that @value{GDBN} is built for.
+
+@findex allocate_symtab
+Update @code{allocate_symtab} in @file{symfile.c} and/or symbol-reading
+code so that the language of each symtab (source file) is set properly.
+This is used to determine the language to use at each stack frame level.
+Currently, the language is set based upon the extension of the source
+file. If the language can be better inferred from the symbol
+information, please set the language of the symtab in the symbol-reading
+code.
+
+@findex print_subexp
+@findex op_print_tab
+Add helper code to @code{print_subexp} (in @file{expprint.c}) to handle any new
+expression opcodes you have added to @file{expression.h}. Also, add the
+printed representations of your operators to @code{op_print_tab}.
+
+@item Add a place of call
+
+@findex parse_exp_1
+Add a call to @code{@var{lang}_parse()} and @code{@var{lang}_error} in
+@code{parse_exp_1} (defined in @file{parse.c}).
+
+@item Use macros to trim code
+
+@cindex trimming language-dependent code
+The user has the option of building @value{GDBN} for some or all of the
+languages. If the user decides to build @value{GDBN} for the language
+@var{lang}, then every file dependent on @file{language.h} will have the
+macro @code{_LANG_@var{lang}} defined in it. Use @code{#ifdef}s to
+leave out large routines that the user won't need if he or she is not
+using your language.
+
+Note that you do not need to do this in your YACC parser, since if @value{GDBN}
+is not build for @var{lang}, then @file{@var{lang}-exp.tab.o} (the
+compiled form of your parser) is not linked into @value{GDBN} at all.
+
+See the file @file{configure.in} for how @value{GDBN} is configured
+for different languages.
+
+@item Edit @file{Makefile.in}
+
+Add dependencies in @file{Makefile.in}. Make sure you update the macro
+variables such as @code{HFILES} and @code{OBJS}, otherwise your code may
+not get linked in, or, worse yet, it may not get @code{tar}red into the
+distribution!
+@end table
+
+
+@node Host Definition
+
+@chapter Host Definition
+
+@emph{Maintainer's note: In theory, new targets no longer need to use
+the host framework described below. Instead it should be possible to
+handle everything using autoconf. Patches eliminating this framework
+welcome.}
+
+With the advent of Autoconf, it's rarely necessary to have host
+definition machinery anymore.
+
+@section Adding a New Host
+
+@cindex adding a new host
+@cindex host, adding
+Most of @value{GDBN}'s host configuration support happens via
+Autoconf. New host-specific definitions should be rarely needed.
+@value{GDBN} still uses the host-specific definitions and files listed
+below, but these mostly exist for historical reasons, and should
+eventually disappear.
+
+Several files control @value{GDBN}'s configuration for host systems:
+
+@table @file
+@vindex XDEPFILES
+@item gdb/config/@var{arch}/@var{xyz}.mh
+Specifies Makefile fragments needed when hosting on machine @var{xyz}.
+In particular, this lists the required machine-dependent object files,
+by defining @samp{XDEPFILES=@dots{}}. Also specifies the header file
+which describes host @var{xyz}, by defining @code{XM_FILE=
+xm-@var{xyz}.h}. You can also define @code{CC}, @code{SYSV_DEFINE},
+@code{XM_CFLAGS}, @code{XM_ADD_FILES}, @code{XM_CLIBS}, @code{XM_CDEPS},
+etc.; see @file{Makefile.in}.
+
+@item gdb/config/@var{arch}/xm-@var{xyz}.h
+(@file{xm.h} is a link to this file, created by @code{configure}). Contains C
+macro definitions describing the host system environment, such as byte
+order, host C compiler and library.
+
+@item gdb/@var{xyz}-xdep.c
+Contains any miscellaneous C code required for this machine as a host.
+On most machines it doesn't exist at all. If it does exist, put
+@file{@var{xyz}-xdep.o} into the @code{XDEPFILES} line in
+@file{gdb/config/@var{arch}/@var{xyz}.mh}.
+@end table
+
+@subheading Generic Host Support Files
+
+@cindex generic host support
+There are some ``generic'' versions of routines that can be used by
+various systems. These can be customized in various ways by macros
+defined in your @file{xm-@var{xyz}.h} file. If these routines work for
+the @var{xyz} host, you can just include the generic file's name (with
+@samp{.o}, not @samp{.c}) in @code{XDEPFILES}.
+
+Otherwise, if your machine needs custom support routines, you will need
+to write routines that perform the same functions as the generic file.
+Put them into @code{@var{xyz}-xdep.c}, and put @code{@var{xyz}-xdep.o}
+into @code{XDEPFILES}.
+
+@table @file
+@cindex remote debugging support
+@cindex serial line support
+@item ser-unix.c
+This contains serial line support for Unix systems. This is always
+included, via the makefile variable @code{SER_HARDWIRE}; override this
+variable in the @file{.mh} file to avoid it.
+
+@item ser-go32.c
+This contains serial line support for 32-bit programs running under DOS,
+using the DJGPP (a.k.a.@: GO32) execution environment.
+
+@cindex TCP remote support
+@item ser-tcp.c
+This contains generic TCP support using sockets.
+@end table
+
+@section Host Conditionals
+
+When @value{GDBN} is configured and compiled, various macros are
+defined or left undefined, to control compilation based on the
+attributes of the host system. These macros and their meanings (or if
+the meaning is not documented here, then one of the source files where
+they are used is indicated) are:
+
+@ftable @code
+@item @value{GDBN}INIT_FILENAME
+The default name of @value{GDBN}'s initialization file (normally
+@file{.gdbinit}).
+
+@item NO_STD_REGS
+This macro is deprecated.
+
+@item NO_SYS_FILE
+Define this if your system does not have a @code{<sys/file.h>}.
+
+@item SIGWINCH_HANDLER
+If your host defines @code{SIGWINCH}, you can define this to be the name
+of a function to be called if @code{SIGWINCH} is received.
+
+@item SIGWINCH_HANDLER_BODY
+Define this to expand into code that will define the function named by
+the expansion of @code{SIGWINCH_HANDLER}.
-@table @code
-@item ALIGN_SIZE
-alloca.c
-@item BLOCK_ADDRESS_FUNCTION_RELATIVE
-dbxread.c
-@item GDBINIT_FILENAME
-main.c
-@item KERNELDEBUG
-tm-hppa.h
-@item MEM_FNS_DECLARED
-Your host config file defines this if it includes
-declarations of @code{memcpy} and @code{memset}. Define this
-to avoid conflicts between the native include
-files and the declarations in @file{defs.h}.
-@item NO_SYS_FILE
-dbxread.c
-@item PYRAMID_CONTROL_FRAME_DEBUGGING
-pyr-xdep.c
-@item SIGWINCH_HANDLER_BODY
-utils.c
-@item 1
-buildsym.c
-@item 1
-dbxread.c
-@item 1
-dbxread.c
-@item 1
-buildsym.c
-@item 1
-dwarfread.c
-@item 1
-valops.c
-@item 1
-valops.c
-@item 1
-pyr-xdep.c
-@item ADDITIONAL_OPTIONS
-main.c
-@item ADDITIONAL_OPTION_CASES
-main.c
-@item ADDITIONAL_OPTION_HANDLER
-main.c
-@item ADDITIONAL_OPTION_HELP
-main.c
-@item ADDR_BITS_REMOVE
-defs.h
-@item AIX_BUGGY_PTRACE_CONTINUE
-infptrace.c
@item ALIGN_STACK_ON_STARTUP
-main.c
-@item ALTOS
-altos-xdep.c
-@item ALTOS_AS
-xm-altos.h
-@item ASCII_COFF
-remote-adapt.c
-@item BADMAG
-coffread.c
-@item BCS
-tm-delta88.h
-@item BEFORE_MAIN_LOOP_HOOK
-main.c
-@item BELIEVE_PCC_PROMOTION
-coffread.c
-@item BELIEVE_PCC_PROMOTION_TYPE
-stabsread.c
-@item BIG_ENDIAN
-defs.h
-@item BITS_BIG_ENDIAN
-defs.h
-@item BKPT_AT_MAIN
-solib.c
-@item BLOCK_ADDRESS_ABSOLUTE
-dbxread.c
-@item BPT_VECTOR
-tm-m68k.h
-@item BREAKPOINT
-tm-m68k.h
-@item BREAKPOINT_DEBUG
-breakpoint.c
-@item BROKEN_LARGE_ALLOCA
-Avoid large @code{alloca}'s. For example, on sun's, Large alloca's fail
-because the attempt to increase the stack limit in main() fails because
-shared libraries are allocated just below the initial stack limit. The
-SunOS kernel will not allow the stack to grow into the area occupied by
-the shared libraries.
-@item BSTRING
-regex.c
-@item CALL_DUMMY
-valops.c
-@item CALL_DUMMY_LOCATION
-inferior.h
-@item CALL_DUMMY_STACK_ADJUST
-valops.c
-@item CANNOT_FETCH_REGISTER
-hppabsd-xdep.c
-@item CANNOT_STORE_REGISTER
-findvar.c
-@item CFRONT_PRODUCER
-dwarfread.c
-@item CHILD_PREPARE_TO_STORE
-inftarg.c
-@item CLEAR_DEFERRED_STORES
-inflow.c
-@item CLEAR_SOLIB
-objfiles.c
-@item COFF_ENCAPSULATE
-hppabsd-tdep.c
-@item COFF_FORMAT
-symm-tdep.c
-@item CORE_NEEDS_RELOCATION
-stack.c
-@item CPLUS_MARKER
-cplus-dem.c
-@item CREATE_INFERIOR_HOOK
-infrun.c
-@item C_ALLOCA
-regex.c
-@item C_GLBLREG
-coffread.c
-@item DBXREAD_ONLY
-partial-stab.h
-@item DBX_PARM_SYMBOL_CLASS
-stabsread.c
-@item DEBUG
-remote-adapt.c
-@item DEBUG_INFO
-partial-stab.h
-@item DEBUG_PTRACE
-hppabsd-xdep.c
-@item DECR_PC_AFTER_BREAK
-breakpoint.c
+@cindex stack alignment
+Define this if your system is of a sort that will crash in
+@code{tgetent} if the stack happens not to be longword-aligned when
+@code{main} is called. This is a rare situation, but is known to occur
+on several different types of systems.
+
+@item CRLF_SOURCE_FILES
+@cindex DOS text files
+Define this if host files use @code{\r\n} rather than @code{\n} as a
+line terminator. This will cause source file listings to omit @code{\r}
+characters when printing and it will allow @code{\r\n} line endings of files
+which are ``sourced'' by gdb. It must be possible to open files in binary
+mode using @code{O_BINARY} or, for fopen, @code{"rb"}.
+
@item DEFAULT_PROMPT
-main.c
-@item DELTA88
-m88k-xdep.c
+@cindex prompt
+The default value of the prompt string (normally @code{"(gdb) "}).
+
@item DEV_TTY
-symmisc.c
-@item DGUX
-m88k-xdep.c
-@item DISABLE_UNSETTABLE_BREAK
-breakpoint.c
-@item DONT_USE_REMOTE
-remote.c
-@item DO_DEFERRED_STORES
-infrun.c
-@item DO_REGISTERS_INFO
-infcmd.c
-@item END_OF_TEXT_DEFAULT
-dbxread.c
-@item EXTERN
-buildsym.h
-@item EXTRACT_RETURN_VALUE
-tm-m68k.h
-@item EXTRACT_STRUCT_VALUE_ADDRESS
-values.c
-@item EXTRA_FRAME_INFO
-frame.h
-@item EXTRA_SYMTAB_INFO
-symtab.h
-@item FILES_INFO_HOOK
-target.c
-@item FIXME
-coffread.c
-@item FLOAT_INFO
-infcmd.c
+@cindex terminal device
+The name of the generic TTY device, defaults to @code{"/dev/tty"}.
+
+@item FCLOSE_PROVIDED
+Define this if the system declares @code{fclose} in the headers included
+in @code{defs.h}. This isn't needed unless your compiler is unusually
+anal.
+
@item FOPEN_RB
-defs.h
-@item FP0_REGNUM
-a68v-xdep.c
-@item FPC_REGNUM
-mach386-xdep.c
-@item FP_REGNUM
-parse.c
-@item FRAMELESS_FUNCTION_INVOCATION
-blockframe.c
-@item FRAME_ARGS_ADDRESS_CORRECT
-stack.c
-@item FRAME_CHAIN_COMBINE
-blockframe.c
-@item FRAME_CHAIN_VALID
-frame.h
-@item FRAME_CHAIN_VALID_ALTERNATE
-frame.h
-@item FRAME_FIND_SAVED_REGS
-stack.c
-@item FRAME_GET_BASEREG_VALUE
-frame.h
-@item FRAME_NUM_ARGS
-tm-m68k.h
-@item FRAME_SPECIFICATION_DYADIC
-stack.c
-@item FUNCTION_EPILOGUE_SIZE
-coffread.c
-@item F_OK
-xm-ultra3.h
-@item GCC2_COMPILED_FLAG_SYMBOL
-dbxread.c
-@item GCC_COMPILED_FLAG_SYMBOL
-dbxread.c
-@item GCC_MANGLE_BUG
-symtab.c
-@item GCC_PRODUCER
-dwarfread.c
-@item GET_SAVED_REGISTER
-findvar.c
-@item GPLUS_PRODUCER
-dwarfread.c
-@item GR64_REGNUM
-remote-adapt.c
-@item GR64_REGNUM
-remote-mm.c
-@item HANDLE_RBRAC
-partial-stab.h
-@item HAVE_68881
-m68k-tdep.c
+Define this if binary files are opened the same way as text files.
+
+@item GETENV_PROVIDED
+Define this if the system declares @code{getenv} in its headers included
+in @code{defs.h}. This isn't needed unless your compiler is unusually
+anal.
+
@item HAVE_MMAP
+@findex mmap
In some cases, use the system call @code{mmap} for reading symbol
tables. For some machines this allows for sharing and quick updates.
-@item HAVE_REGISTER_WINDOWS
-findvar.c
-@item HAVE_SIGSETMASK
-main.c
+
@item HAVE_TERMIO
-inflow.c
-@item HEADER_SEEK_FD
-arm-tdep.c
-@item HOSTING_ONLY
-xm-rtbsd.h
-@item HOST_BYTE_ORDER
-ieee-float.c
-@item HPUX_ASM
-xm-hp300hpux.h
-@item HPUX_VERSION_5
-hp300ux-xdep.c
-@item HP_OS_BUG
-infrun.c
-@item I80960
-remote-vx.c
-@item IEEE_DEBUG
-ieee-float.c
-@item IEEE_FLOAT
-valprint.c
-@item IGNORE_SYMBOL
-dbxread.c
-@item INIT_EXTRA_FRAME_INFO
-blockframe.c
-@item INIT_EXTRA_SYMTAB_INFO
-symfile.c
-@item INIT_FRAME_PC
-blockframe.c
-@item INNER_THAN
-valops.c
+Define this if the host system has @code{termio.h}.
+
@item INT_MAX
-defs.h
-@item INT_MIN
-defs.h
-@item IN_GDB
-i960-pinsn.c
-@item IN_SIGTRAMP
-infrun.c
-@item IN_SOLIB_TRAMPOLINE
-infrun.c
+@itemx INT_MIN
+@itemx LONG_MAX
+@itemx UINT_MAX
+@itemx ULONG_MAX
+Values for host-side constants.
+
@item ISATTY
-main.c
-@item IS_TRAPPED_INTERNALVAR
-values.c
-@item KERNELDEBUG
-dbxread.c
-@item KERNEL_DEBUGGING
-tm-ultra3.h
-@item KERNEL_U_ADDR
-Define this to the address of the @code{u} structure (the ``user struct'',
-also known as the ``u-page'') in kernel virtual memory. GDB needs to know
-this so that it can subtract this address from absolute addresses in
-the upage, that are obtained via ptrace or from core files. On systems
-that don't need this value, set it to zero.
-@item KERNEL_U_ADDR_BSD
-Define this to cause GDB to determine the address of @code{u} at runtime,
-by using Berkeley-style @code{nlist} on the kernel's image in the root
-directory.
-@item KERNEL_U_ADDR_HPUX
-Define this to cause GDB to determine the address of @code{u} at runtime,
-by using HP-style @code{nlist} on the kernel's image in the root
-directory.
-@item LCC_PRODUCER
-dwarfread.c
-@item LITTLE_ENDIAN
-defs.h
-@item LOG_FILE
-remote-adapt.c
-@item LONGERNAMES
-cplus-dem.c
+Substitute for isatty, if not available.
+
@item LONGEST
-defs.h
-@item LONG_LONG
-defs.h
-@item LONG_MAX
-defs.h
+This is the longest integer type available on the host. If not defined,
+it will default to @code{long long} or @code{long}, depending on
+@code{CC_HAS_LONG_LONG}.
+
+@item CC_HAS_LONG_LONG
+@cindex @code{long long} data type
+Define this if the host C compiler supports @code{long long}. This is set
+by the @code{configure} script.
+
+@item PRINTF_HAS_LONG_LONG
+Define this if the host can handle printing of long long integers via
+the printf format conversion specifier @code{ll}. This is set by the
+@code{configure} script.
+
+@item HAVE_LONG_DOUBLE
+Define this if the host C compiler supports @code{long double}. This is
+set by the @code{configure} script.
+
+@item PRINTF_HAS_LONG_DOUBLE
+Define this if the host can handle printing of long double float-point
+numbers via the printf format conversion specifier @code{Lg}. This is
+set by the @code{configure} script.
+
+@item SCANF_HAS_LONG_DOUBLE
+Define this if the host can handle the parsing of long double
+float-point numbers via the scanf format conversion specifier
+@code{Lg}. This is set by the @code{configure} script.
+
@item LSEEK_NOT_LINEAR
-source.c
-@item L_LNNO32
-coffread.c
+Define this if @code{lseek (n)} does not necessarily move to byte number
+@code{n} in the file. This is only used when reading source files. It
+is normally faster to define @code{CRLF_SOURCE_FILES} when possible.
+
@item L_SET
-This macro is used as the argument to lseek (or, most commonly, bfd_seek).
-FIXME, it should be replaced by SEEK_SET instead, which is the POSIX equivalent.
-@item MACHKERNELDEBUG
-hppabsd-tdep.c
-@item MAIN
-cplus-dem.c
-@item MAINTENANCE
-dwarfread.c
-@item MAINTENANCE_CMDS
-breakpoint.c
-@item MAINTENANCE_CMDS
-maint.c
+This macro is used as the argument to @code{lseek} (or, most commonly,
+@code{bfd_seek}). FIXME, should be replaced by SEEK_SET instead,
+which is the POSIX equivalent.
+
@item MALLOC_INCOMPATIBLE
Define this if the system's prototype for @code{malloc} differs from the
-@sc{ANSI} definition.
-@item MIPSEL
-mips-tdep.c
+@sc{ansi} definition.
+
@item MMAP_BASE_ADDRESS
When using HAVE_MMAP, the first mapping should go at this address.
+
@item MMAP_INCREMENT
when using HAVE_MMAP, this is the increment between mappings.
-@item MONO
-ser-go32.c
-@item MOTOROLA
-xm-altos.h
-@item NBPG
-altos-xdep.c
-@item NEED_POSIX_SETPGID
-infrun.c
-@item NEED_TEXT_START_END
-exec.c
-@item NFAILURES
-regex.c
-@item NNPC_REGNUM
-infrun.c
+
@item NORETURN
-defs.h
-@item NOTDEF
-regex.c
-@item NOTDEF
-remote-adapt.c
-@item NOTDEF
-remote-mm.c
-@item NOTICE_SIGNAL_HANDLING_CHANGE
-infrun.c
-@item NO_HIF_SUPPORT
-remote-mm.c
-@item NO_JOB_CONTROL
-signals.h
-@item NO_MMALLOC
-GDB will use the @code{mmalloc} library for memory allocation for symbol
-reading, unless this symbol is defined. Define it on systems
-on which @code{mmalloc} does not
-work for some reason. One example is the DECstation, where its RPC
-library can't cope with our redefinition of @code{malloc} to call
-@code{mmalloc}. When defining @code{NO_MMALLOC}, you will also have
-to override the setting of @code{MMALLOC_LIB} to empty, in the Makefile.
-Therefore, this define is usually set on the command line by overriding
-@code{MMALLOC_DISABLE} in @file{config/*/*.mh}, rather than by defining
-it in @file{xm-*.h}.
-@item NO_MMALLOC_CHECK
+If defined, this should be one or more tokens, such as @code{volatile},
+that can be used in both the declaration and definition of functions to
+indicate that they never return. The default is already set correctly
+if compiling with GCC. This will almost never need to be defined.
+
+@item ATTR_NORETURN
+If defined, this should be one or more tokens, such as
+@code{__attribute__ ((noreturn))}, that can be used in the declarations
+of functions to indicate that they never return. The default is already
+set correctly if compiling with GCC. This will almost never need to be
+defined.
+
+@item USE_GENERIC_DUMMY_FRAMES
+@cindex generic dummy frames
+Define this to 1 if the target is using the generic inferior function
+call code. See @code{blockframe.c} for more information.
+
+@item USE_MMALLOC
+@findex mmalloc
+@value{GDBN} will use the @code{mmalloc} library for memory allocation
+for symbol reading if this symbol is defined. Be careful defining it
+since there are systems on which @code{mmalloc} does not work for some
+reason. One example is the DECstation, where its RPC library can't
+cope with our redefinition of @code{malloc} to call @code{mmalloc}.
+When defining @code{USE_MMALLOC}, you will also have to set
+@code{MMALLOC} in the Makefile, to point to the @code{mmalloc} library. This
+define is set when you configure with @samp{--with-mmalloc}.
+
+@item NO_MMCHECK
+@findex mmcheck
Define this if you are using @code{mmalloc}, but don't want the overhead
-of checking the heap with @code{mmcheck}.
+of checking the heap with @code{mmcheck}. Note that on some systems,
+the C runtime makes calls to @code{malloc} prior to calling @code{main}, and if
+@code{free} is ever called with these pointers after calling
+@code{mmcheck} to enable checking, a memory corruption abort is certain
+to occur. These systems can still use @code{mmalloc}, but must define
+@code{NO_MMCHECK}.
+
+@item MMCHECK_FORCE
+Define this to 1 if the C runtime allocates memory prior to
+@code{mmcheck} being called, but that memory is never freed so we don't
+have to worry about it triggering a memory corruption abort. The
+default is 0, which means that @code{mmcheck} will only install the heap
+checking functions if there has not yet been any memory allocation
+calls, and if it fails to install the functions, @value{GDBN} will issue a
+warning. This is currently defined if you configure using
+@samp{--with-mmalloc}.
+
@item NO_SIGINTERRUPT
-remote-adapt.c
-@item NO_SINGLE_STEP
-infptrace.c
-@item NPC_REGNUM
-infcmd.c
-@item NS32K_SVC_IMMED_OPERANDS
-ns32k-opcode.h
-@item NUMERIC_REG_NAMES
-mips-tdep.c
-@item N_SETV
-dbxread.c
-@item N_SET_MAGIC
-hppabsd-tdep.c
-@item NaN
-tm-umax.h
-@item ONE_PROCESS_WRITETEXT
-breakpoint.c
-@item O_BINARY
-exec.c
-@item O_RDONLY
-xm-ultra3.h
-@item PC
-convx-opcode.h
-@item PCC_SOL_BROKEN
-dbxread.c
-@item PC_IN_CALL_DUMMY
-inferior.h
-@item PC_LOAD_SEGMENT
-stack.c
-@item PC_REGNUM
-parse.c
-@item PRINT_RANDOM_SIGNAL
-infcmd.c
-@item PRINT_REGISTER_HOOK
-infcmd.c
-@item PRINT_TYPELESS_INTEGER
-valprint.c
-@item PROCESS_LINENUMBER_HOOK
-buildsym.c
-@item PROLOGUE_FIRSTLINE_OVERLAP
-infrun.c
-@item PSIGNAL_IN_SIGNAL_H
-defs.h
-@item PS_REGNUM
-parse.c
-@item PUSH_ARGUMENTS
-valops.c
-@item PYRAMID_CONTROL_FRAME_DEBUGGING
-pyr-xdep.c
-@item PYRAMID_CORE
-pyr-xdep.c
-@item PYRAMID_PTRACE
-pyr-xdep.c
-@item REGISTER_BYTES
-remote.c
-@item REGISTER_NAMES
-tm-a29k.h
-@item REG_STACK_SEGMENT
-exec.c
-@item REG_STRUCT_HAS_ADDR
-findvar.c
-@item RE_NREGS
-regex.h
-@item R_FP
-dwarfread.c
-@item R_OK
-xm-altos.h
-@item SDB_REG_TO_REGNUM
-coffread.c
-@item SEEK_END
-state.c
-@item SEEK_SET
-state.c
-@item SEM
-coffread.c
-@item SET_STACK_LIMIT_HUGE
-When defined, stack limits will be raised to their maximum. Use this
-if your host supports @code{setrlimit} and you have trouble with
-@code{stringtab} in @file{dbxread.c}.
-
-Also used in @file{fork-child.c} to return stack limits before child
-processes are forked.
-@item SHELL_COMMAND_CONCAT
-infrun.c
-@item SHELL_FILE
-infrun.c
-@item SHIFT_INST_REGS
-breakpoint.c
-@item SIGN_EXTEND_CHAR
-regex.c
-@item SIGTRAP_STOP_AFTER_LOAD
-infrun.c
-@item SKIP_PROLOGUE
-tm-m68k.h
-@item SKIP_PROLOGUE_FRAMELESS_P
-blockframe.c
-@item SKIP_TRAMPOLINE_CODE
-infrun.c
-@item SOLIB_ADD
-core.c
-@item SOLIB_CREATE_INFERIOR_HOOK
-infrun.c
-@item SP_REGNUM
-parse.c
-@item STAB_REG_TO_REGNUM
-stabsread.h
-@item STACK_ALIGN
-valops.c
-@item STACK_DIRECTION
-alloca.c
-@item START_INFERIOR_TRAPS_EXPECTED
-infrun.c
+@findex siginterrupt
+Define this to indicate that @code{siginterrupt} is not available.
+
+@item SEEK_CUR
+@itemx SEEK_SET
+Define these to appropriate value for the system @code{lseek}, if not already
+defined.
+
@item STOP_SIGNAL
-main.c
-@item STORE_RETURN_VALUE
-tm-m68k.h
-@item SUN4_COMPILER_FEATURE
-infrun.c
-@item SUN_FIXED_LBRAC_BUG
-dbxread.c
-@item SVR4_SHARED_LIBS
-solib.c
-@item SWITCH_ENUM_BUG
-regex.c
-@item SYM1
-tm-ultra3.h
-@item SYMBOL_RELOADING_DEFAULT
-symfile.c
-@item SYNTAX_TABLE
-regex.c
-@item Sword
-regex.c
-@item TDESC
-infrun.c
-@item TIOCGETC
-inflow.c
-@item TIOCGLTC
-inflow.c
-@item TIOCGPGRP
-inflow.c
-@item TIOCLGET
-inflow.c
-@item TIOCLSET
-inflow.c
-@item TIOCNOTTY
-inflow.c
-@item TM_FILE_OVERRIDE
-defs.h
-@item T_ARG
-coffread.c
-@item T_VOID
-coffread.c
-@item UINT_MAX
-defs.h
-@item UPAGES
-altos-xdep.c
-@item USER
-m88k-tdep.c
-@item USE_GAS
-xm-news.h
+This is the signal for stopping @value{GDBN}. Defaults to
+@code{SIGTSTP}. (Only redefined for the Convex.)
+
@item USE_O_NOCTTY
-inflow.c
-@item USE_STRUCT_CONVENTION
-values.c
+Define this if the interior's tty should be opened with the @code{O_NOCTTY}
+flag. (FIXME: This should be a native-only flag, but @file{inflow.c} is
+always linked in.)
+
@item USG
-Means that System V (prior to SVR4) include files are in use.
-(FIXME: This symbol is abused in @file{infrun.c}, @file{regex.c},
-@file{remote-nindy.c}, and @file{utils.c} for other things, at the moment.)
-@item USIZE
-xm-m88k.h
-@item U_FPSTATE
-i386-xdep.c
-@item VARIABLES_INSIDE_BLOCK
-dbxread.c
-@item WRS_ORIG
-remote-vx.c
-@item _LANG_c
-language.c
-@item _LANG_m2
-language.c
-@item __GNUC__
-news-xdep.c
-@item __GO32__
-inflow.c
-@item __HAVE_68881__
-m68k-stub.c
-@item __HPUX_ASM__
-xm-hp300hpux.h
-@item __INT_VARARGS_H
-printcmd.c
-@item __not_on_pyr_yet
-pyr-xdep.c
-@item alloca
-defs.h
-@item const
-defs.h
-@item GOULD_PN
-gould-pinsn.c
-@item emacs
-alloca.c
-@item hp800
-xm-hppabsd.h
-@item hpux
-hppabsd-core.c
+Means that System V (prior to SVR4) include files are in use. (FIXME:
+This symbol is abused in @file{infrun.c}, @file{regex.c},
+@file{remote-nindy.c}, and @file{utils.c} for other things, at the
+moment.)
+
@item lint
-valarith.c
-@item longest_to_int
-defs.h
-@item mc68020
-m68k-stub.c
-@item notdef
-gould-pinsn.c
-@item ns32k_opcodeT
-ns32k-opcode.h
-@item sgi
-mips-tdep.c
-@item sparc
-regex.c
-@item static
-alloca.c
-@item sun
-m68k-tdep.c
-@item sun386
-tm-sun386.h
-@item test
-regex.c
-@item ultrix
-xm-mips.h
+Define this to help placate @code{lint} in some situations.
+
@item volatile
-defs.h
-@item x_name
-coffread.c
-@item x_zeroes
-coffread.c
-@end table
+Define this to override the defaults of @code{__volatile__} or
+@code{/**/}.
+@end ftable
+
+
+@node Target Architecture Definition
+
+@chapter Target Architecture Definition
+
+@cindex target architecture definition
+@value{GDBN}'s target architecture defines what sort of
+machine-language programs @value{GDBN} can work with, and how it works
+with them.
+
+The target architecture object is implemented as the C structure
+@code{struct gdbarch *}. The structure, and its methods, are generated
+using the Bourne shell script @file{gdbarch.sh}.
+
+@section Registers and Memory
+
+@value{GDBN}'s model of the target machine is rather simple.
+@value{GDBN} assumes the machine includes a bank of registers and a
+block of memory. Each register may have a different size.
+
+@value{GDBN} does not have a magical way to match up with the
+compiler's idea of which registers are which; however, it is critical
+that they do match up accurately. The only way to make this work is
+to get accurate information about the order that the compiler uses,
+and to reflect that in the @code{REGISTER_NAME} and related macros.
+
+@value{GDBN} can handle big-endian, little-endian, and bi-endian architectures.
+
+@section Pointers Are Not Always Addresses
+@cindex pointer representation
+@cindex address representation
+@cindex word-addressed machines
+@cindex separate data and code address spaces
+@cindex spaces, separate data and code address
+@cindex address spaces, separate data and code
+@cindex code pointers, word-addressed
+@cindex converting between pointers and addresses
+@cindex D10V addresses
+
+On almost all 32-bit architectures, the representation of a pointer is
+indistinguishable from the representation of some fixed-length number
+whose value is the byte address of the object pointed to. On such
+machines, the words ``pointer'' and ``address'' can be used interchangeably.
+However, architectures with smaller word sizes are often cramped for
+address space, so they may choose a pointer representation that breaks this
+identity, and allows a larger code address space.
+
+For example, the Mitsubishi D10V is a 16-bit VLIW processor whose
+instructions are 32 bits long@footnote{Some D10V instructions are
+actually pairs of 16-bit sub-instructions. However, since you can't
+jump into the middle of such a pair, code addresses can only refer to
+full 32 bit instructions, which is what matters in this explanation.}.
+If the D10V used ordinary byte addresses to refer to code locations,
+then the processor would only be able to address 64kb of instructions.
+However, since instructions must be aligned on four-byte boundaries, the
+low two bits of any valid instruction's byte address are always
+zero---byte addresses waste two bits. So instead of byte addresses,
+the D10V uses word addresses---byte addresses shifted right two bits---to
+refer to code. Thus, the D10V can use 16-bit words to address 256kb of
+code space.
+
+However, this means that code pointers and data pointers have different
+forms on the D10V. The 16-bit word @code{0xC020} refers to byte address
+@code{0xC020} when used as a data address, but refers to byte address
+@code{0x30080} when used as a code address.
+
+(The D10V also uses separate code and data address spaces, which also
+affects the correspondence between pointers and addresses, but we're
+going to ignore that here; this example is already too long.)
+
+To cope with architectures like this---the D10V is not the only
+one!---@value{GDBN} tries to distinguish between @dfn{addresses}, which are
+byte numbers, and @dfn{pointers}, which are the target's representation
+of an address of a particular type of data. In the example above,
+@code{0xC020} is the pointer, which refers to one of the addresses
+@code{0xC020} or @code{0x30080}, depending on the type imposed upon it.
+@value{GDBN} provides functions for turning a pointer into an address
+and vice versa, in the appropriate way for the current architecture.
+
+Unfortunately, since addresses and pointers are identical on almost all
+processors, this distinction tends to bit-rot pretty quickly. Thus,
+each time you port @value{GDBN} to an architecture which does
+distinguish between pointers and addresses, you'll probably need to
+clean up some architecture-independent code.
+
+Here are functions which convert between pointers and addresses:
+
+@deftypefun CORE_ADDR extract_typed_address (void *@var{buf}, struct type *@var{type})
+Treat the bytes at @var{buf} as a pointer or reference of type
+@var{type}, and return the address it represents, in a manner
+appropriate for the current architecture. This yields an address
+@value{GDBN} can use to read target memory, disassemble, etc. Note that
+@var{buf} refers to a buffer in @value{GDBN}'s memory, not the
+inferior's.
+
+For example, if the current architecture is the Intel x86, this function
+extracts a little-endian integer of the appropriate length from
+@var{buf} and returns it. However, if the current architecture is the
+D10V, this function will return a 16-bit integer extracted from
+@var{buf}, multiplied by four if @var{type} is a pointer to a function.
+
+If @var{type} is not a pointer or reference type, then this function
+will signal an internal error.
+@end deftypefun
+
+@deftypefun CORE_ADDR store_typed_address (void *@var{buf}, struct type *@var{type}, CORE_ADDR @var{addr})
+Store the address @var{addr} in @var{buf}, in the proper format for a
+pointer of type @var{type} in the current architecture. Note that
+@var{buf} refers to a buffer in @value{GDBN}'s memory, not the
+inferior's.
+
+For example, if the current architecture is the Intel x86, this function
+stores @var{addr} unmodified as a little-endian integer of the
+appropriate length in @var{buf}. However, if the current architecture
+is the D10V, this function divides @var{addr} by four if @var{type} is
+a pointer to a function, and then stores it in @var{buf}.
+
+If @var{type} is not a pointer or reference type, then this function
+will signal an internal error.
+@end deftypefun
+
+@deftypefun CORE_ADDR value_as_address (value_ptr @var{val})
+Assuming that @var{val} is a pointer, return the address it represents,
+as appropriate for the current architecture.
+
+This function actually works on integral values, as well as pointers.
+For pointers, it performs architecture-specific conversions as
+described above for @code{extract_typed_address}.
+@end deftypefun
+
+@deftypefun CORE_ADDR value_from_pointer (struct type *@var{type}, CORE_ADDR @var{addr})
+Create and return a value representing a pointer of type @var{type} to
+the address @var{addr}, as appropriate for the current architecture.
+This function performs architecture-specific conversions as described
+above for @code{store_typed_address}.
+@end deftypefun
+
+
+@value{GDBN} also provides functions that do the same tasks, but assume
+that pointers are simply byte addresses; they aren't sensitive to the
+current architecture, beyond knowing the appropriate endianness.
+
+@deftypefun CORE_ADDR extract_address (void *@var{addr}, int len)
+Extract a @var{len}-byte number from @var{addr} in the appropriate
+endianness for the current architecture, and return it. Note that
+@var{addr} refers to @value{GDBN}'s memory, not the inferior's.
+
+This function should only be used in architecture-specific code; it
+doesn't have enough information to turn bits into a true address in the
+appropriate way for the current architecture. If you can, use
+@code{extract_typed_address} instead.
+@end deftypefun
+
+@deftypefun void store_address (void *@var{addr}, int @var{len}, LONGEST @var{val})
+Store @var{val} at @var{addr} as a @var{len}-byte integer, in the
+appropriate endianness for the current architecture. Note that
+@var{addr} refers to a buffer in @value{GDBN}'s memory, not the
+inferior's.
+
+This function should only be used in architecture-specific code; it
+doesn't have enough information to turn a true address into bits in the
+appropriate way for the current architecture. If you can, use
+@code{store_typed_address} instead.
+@end deftypefun
+
+
+Here are some macros which architectures can define to indicate the
+relationship between pointers and addresses. These have default
+definitions, appropriate for architectures on which all pointers are
+simple unsigned byte addresses.
+
+@deftypefn {Target Macro} CORE_ADDR POINTER_TO_ADDRESS (struct type *@var{type}, char *@var{buf})
+Assume that @var{buf} holds a pointer of type @var{type}, in the
+appropriate format for the current architecture. Return the byte
+address the pointer refers to.
+
+This function may safely assume that @var{type} is either a pointer or a
+C@t{++} reference type.
+@end deftypefn
+
+@deftypefn {Target Macro} void ADDRESS_TO_POINTER (struct type *@var{type}, char *@var{buf}, CORE_ADDR @var{addr})
+Store in @var{buf} a pointer of type @var{type} representing the address
+@var{addr}, in the appropriate format for the current architecture.
+
+This function may safely assume that @var{type} is either a pointer or a
+C@t{++} reference type.
+@end deftypefn
+
+
+@section Using Different Register and Memory Data Representations
+@cindex raw representation
+@cindex virtual representation
+@cindex representations, raw and virtual
+@cindex register data formats, converting
+@cindex @code{struct value}, converting register contents to
+
+@emph{Maintainer's note: The way GDB manipulates registers is undergoing
+significant change. Many of the macros and functions refered to in the
+sections below are likely to be made obsolete. See the file @file{TODO}
+for more up-to-date information.}
+
+Some architectures use one representation for a value when it lives in a
+register, but use a different representation when it lives in memory.
+In @value{GDBN}'s terminology, the @dfn{raw} representation is the one used in
+the target registers, and the @dfn{virtual} representation is the one
+used in memory, and within @value{GDBN} @code{struct value} objects.
+
+For almost all data types on almost all architectures, the virtual and
+raw representations are identical, and no special handling is needed.
+However, they do occasionally differ. For example:
+
+@itemize @bullet
+@item
+The x86 architecture supports an 80-bit @code{long double} type. However, when
+we store those values in memory, they occupy twelve bytes: the
+floating-point number occupies the first ten, and the final two bytes
+are unused. This keeps the values aligned on four-byte boundaries,
+allowing more efficient access. Thus, the x86 80-bit floating-point
+type is the raw representation, and the twelve-byte loosely-packed
+arrangement is the virtual representation.
+
+@item
+Some 64-bit MIPS targets present 32-bit registers to @value{GDBN} as 64-bit
+registers, with garbage in their upper bits. @value{GDBN} ignores the top 32
+bits. Thus, the 64-bit form, with garbage in the upper 32 bits, is the
+raw representation, and the trimmed 32-bit representation is the
+virtual representation.
+@end itemize
-@node Target Conditionals
-@chapter Target Conditionals
+In general, the raw representation is determined by the architecture, or
+@value{GDBN}'s interface to the architecture, while the virtual representation
+can be chosen for @value{GDBN}'s convenience. @value{GDBN}'s register file,
+@code{registers}, holds the register contents in raw format, and the
+@value{GDBN} remote protocol transmits register values in raw format.
-When GDB is configured and compiled, various macros are defined or left
-undefined, to control compilation based on the attributes of the target
-system. These macros and their meanings are:
+Your architecture may define the following macros to request
+conversions between the raw and virtual format:
-@emph{NOTE: For now, both host and target conditionals are here.
-Eliminate host conditionals from this list as they are identified.}
+@deftypefn {Target Macro} int REGISTER_CONVERTIBLE (int @var{reg})
+Return non-zero if register number @var{reg}'s value needs different raw
+and virtual formats.
+
+You should not use @code{REGISTER_CONVERT_TO_VIRTUAL} for a register
+unless this macro returns a non-zero value for that register.
+@end deftypefn
+
+@deftypefn {Target Macro} int REGISTER_RAW_SIZE (int @var{reg})
+The size of register number @var{reg}'s raw value. This is the number
+of bytes the register will occupy in @code{registers}, or in a @value{GDBN}
+remote protocol packet.
+@end deftypefn
+
+@deftypefn {Target Macro} int REGISTER_VIRTUAL_SIZE (int @var{reg})
+The size of register number @var{reg}'s value, in its virtual format.
+This is the size a @code{struct value}'s buffer will have, holding that
+register's value.
+@end deftypefn
+
+@deftypefn {Target Macro} struct type *REGISTER_VIRTUAL_TYPE (int @var{reg})
+This is the type of the virtual representation of register number
+@var{reg}. Note that there is no need for a macro giving a type for the
+register's raw form; once the register's value has been obtained, @value{GDBN}
+always uses the virtual form.
+@end deftypefn
+
+@deftypefn {Target Macro} void REGISTER_CONVERT_TO_VIRTUAL (int @var{reg}, struct type *@var{type}, char *@var{from}, char *@var{to})
+Convert the value of register number @var{reg} to @var{type}, which
+should always be @code{REGISTER_VIRTUAL_TYPE (@var{reg})}. The buffer
+at @var{from} holds the register's value in raw format; the macro should
+convert the value to virtual format, and place it at @var{to}.
+
+Note that @code{REGISTER_CONVERT_TO_VIRTUAL} and
+@code{REGISTER_CONVERT_TO_RAW} take their @var{reg} and @var{type}
+arguments in different orders.
+
+You should only use @code{REGISTER_CONVERT_TO_VIRTUAL} with registers
+for which the @code{REGISTER_CONVERTIBLE} macro returns a non-zero
+value.
+@end deftypefn
+
+@deftypefn {Target Macro} void REGISTER_CONVERT_TO_RAW (struct type *@var{type}, int @var{reg}, char *@var{from}, char *@var{to})
+Convert the value of register number @var{reg} to @var{type}, which
+should always be @code{REGISTER_VIRTUAL_TYPE (@var{reg})}. The buffer
+at @var{from} holds the register's value in raw format; the macro should
+convert the value to virtual format, and place it at @var{to}.
+
+Note that REGISTER_CONVERT_TO_VIRTUAL and REGISTER_CONVERT_TO_RAW take
+their @var{reg} and @var{type} arguments in different orders.
+@end deftypefn
+
+
+@section Frame Interpretation
+
+@section Inferior Call Setup
+
+@section Compiler Characteristics
+
+@section Target Conditionals
+
+This section describes the macros that you can use to define the target
+machine.
@table @code
-@item PUSH_DUMMY_FRAME
-Used in @samp{call_function_by_hand} to create an artificial stack frame.
-@item POP_FRAME
-Used in @samp{call_function_by_hand} to remove an artificial stack frame.
-@item ALIGN_SIZE
-alloca.c
-@item BLOCK_ADDRESS_FUNCTION_RELATIVE
-dbxread.c
-@item GDBINIT_FILENAME
-main.c
-@item KERNELDEBUG
-tm-hppa.h
-@item NO_SYS_FILE
-dbxread.c
-@item PYRAMID_CONTROL_FRAME_DEBUGGING
-pyr-xdep.c
-@item SIGWINCH_HANDLER_BODY
-utils.c
+
@item ADDITIONAL_OPTIONS
-main.c
-@item ADDITIONAL_OPTION_CASES
-main.c
-@item ADDITIONAL_OPTION_HANDLER
-main.c
-@item ADDITIONAL_OPTION_HELP
-main.c
-@item ADDR_BITS_REMOVE
-defs.h
-@item ALIGN_STACK_ON_STARTUP
-main.c
-@item ALTOS
-altos-xdep.c
-@item ALTOS_AS
-xm-altos.h
-@item ASCII_COFF
-remote-adapt.c
-@item BADMAG
-coffread.c
-@item BCS
-tm-delta88.h
+@itemx ADDITIONAL_OPTION_CASES
+@itemx ADDITIONAL_OPTION_HANDLER
+@itemx ADDITIONAL_OPTION_HELP
+@findex ADDITIONAL_OPTION_HELP
+@findex ADDITIONAL_OPTION_HANDLER
+@findex ADDITIONAL_OPTION_CASES
+@findex ADDITIONAL_OPTIONS
+These are a set of macros that allow the addition of additional command
+line options to @value{GDBN}. They are currently used only for the unsupported
+i960 Nindy target, and should not be used in any other configuration.
+
+@item ADDR_BITS_REMOVE (addr)
+@findex ADDR_BITS_REMOVE
+If a raw machine instruction address includes any bits that are not
+really part of the address, then define this macro to expand into an
+expression that zeroes those bits in @var{addr}. This is only used for
+addresses of instructions, and even then not in all contexts.
+
+For example, the two low-order bits of the PC on the Hewlett-Packard PA
+2.0 architecture contain the privilege level of the corresponding
+instruction. Since instructions must always be aligned on four-byte
+boundaries, the processor masks out these bits to generate the actual
+address of the instruction. ADDR_BITS_REMOVE should filter out these
+bits with an expression such as @code{((addr) & ~3)}.
+
+@item ADDRESS_TO_POINTER (@var{type}, @var{buf}, @var{addr})
+@findex ADDRESS_TO_POINTER
+Store in @var{buf} a pointer of type @var{type} representing the address
+@var{addr}, in the appropriate format for the current architecture.
+This macro may safely assume that @var{type} is either a pointer or a
+C@t{++} reference type.
+@xref{Target Architecture Definition, , Pointers Are Not Always Addresses}.
+
@item BEFORE_MAIN_LOOP_HOOK
-main.c
+@findex BEFORE_MAIN_LOOP_HOOK
+Define this to expand into any code that you want to execute before the
+main loop starts. Although this is not, strictly speaking, a target
+conditional, that is how it is currently being used. Note that if a
+configuration were to define it one way for a host and a different way
+for the target, @value{GDBN} will probably not compile, let alone run
+correctly. This macro is currently used only for the unsupported i960 Nindy
+target, and should not be used in any other configuration.
+
@item BELIEVE_PCC_PROMOTION
-coffread.c
+@findex BELIEVE_PCC_PROMOTION
+Define if the compiler promotes a @code{short} or @code{char}
+parameter to an @code{int}, but still reports the parameter as its
+original type, rather than the promoted type.
+
@item BELIEVE_PCC_PROMOTION_TYPE
-stabsread.c
-@item BIG_ENDIAN
-defs.h
+@findex BELIEVE_PCC_PROMOTION_TYPE
+Define this if @value{GDBN} should believe the type of a @code{short}
+argument when compiled by @code{pcc}, but look within a full int space to get
+its value. Only defined for Sun-3 at present.
+
@item BITS_BIG_ENDIAN
-defs.h
-@item BKPT_AT_MAIN
-solib.c
-@item BLOCK_ADDRESS_ABSOLUTE
-dbxread.c
-@item BPT_VECTOR
-tm-m68k.h
+@findex BITS_BIG_ENDIAN
+Define this if the numbering of bits in the targets does @strong{not} match the
+endianness of the target byte order. A value of 1 means that the bits
+are numbered in a big-endian bit order, 0 means little-endian.
+
@item BREAKPOINT
-tm-m68k.h
-@item BREAKPOINT_DEBUG
-breakpoint.c
-@item BSTRING
-regex.c
+@findex BREAKPOINT
+This is the character array initializer for the bit pattern to put into
+memory where a breakpoint is set. Although it's common to use a trap
+instruction for a breakpoint, it's not required; for instance, the bit
+pattern could be an invalid instruction. The breakpoint must be no
+longer than the shortest instruction of the architecture.
+
+@code{BREAKPOINT} has been deprecated in favor of
+@code{BREAKPOINT_FROM_PC}.
+
+@item BIG_BREAKPOINT
+@itemx LITTLE_BREAKPOINT
+@findex LITTLE_BREAKPOINT
+@findex BIG_BREAKPOINT
+Similar to BREAKPOINT, but used for bi-endian targets.
+
+@code{BIG_BREAKPOINT} and @code{LITTLE_BREAKPOINT} have been deprecated in
+favor of @code{BREAKPOINT_FROM_PC}.
+
+@item REMOTE_BREAKPOINT
+@itemx LITTLE_REMOTE_BREAKPOINT
+@itemx BIG_REMOTE_BREAKPOINT
+@findex BIG_REMOTE_BREAKPOINT
+@findex LITTLE_REMOTE_BREAKPOINT
+@findex REMOTE_BREAKPOINT
+Similar to BREAKPOINT, but used for remote targets.
+
+@code{BIG_REMOTE_BREAKPOINT} and @code{LITTLE_REMOTE_BREAKPOINT} have been
+deprecated in favor of @code{BREAKPOINT_FROM_PC}.
+
+@item BREAKPOINT_FROM_PC (@var{pcptr}, @var{lenptr})
+@findex BREAKPOINT_FROM_PC
+Use the program counter to determine the contents and size of a
+breakpoint instruction. It returns a pointer to a string of bytes
+that encode a breakpoint instruction, stores the length of the string
+to *@var{lenptr}, and adjusts pc (if necessary) to point to the actual
+memory location where the breakpoint should be inserted.
+
+Although it is common to use a trap instruction for a breakpoint, it's
+not required; for instance, the bit pattern could be an invalid
+instruction. The breakpoint must be no longer than the shortest
+instruction of the architecture.
+
+Replaces all the other @var{BREAKPOINT} macros.
+
+@item MEMORY_INSERT_BREAKPOINT (@var{addr}, @var{contents_cache})
+@itemx MEMORY_REMOVE_BREAKPOINT (@var{addr}, @var{contents_cache})
+@findex MEMORY_REMOVE_BREAKPOINT
+@findex MEMORY_INSERT_BREAKPOINT
+Insert or remove memory based breakpoints. Reasonable defaults
+(@code{default_memory_insert_breakpoint} and
+@code{default_memory_remove_breakpoint} respectively) have been
+provided so that it is not necessary to define these for most
+architectures. Architectures which may want to define
+@code{MEMORY_INSERT_BREAKPOINT} and @code{MEMORY_REMOVE_BREAKPOINT} will
+likely have instructions that are oddly sized or are not stored in a
+conventional manner.
+
+It may also be desirable (from an efficiency standpoint) to define
+custom breakpoint insertion and removal routines if
+@code{BREAKPOINT_FROM_PC} needs to read the target's memory for some
+reason.
+
+@item CALL_DUMMY_P
+@findex CALL_DUMMY_P
+A C expresson that is non-zero when the target suports inferior function
+calls.
+
+@item CALL_DUMMY_WORDS
+@findex CALL_DUMMY_WORDS
+Pointer to an array of @code{LONGEST} words of data containing
+host-byte-ordered @code{REGISTER_BYTES} sized values that partially
+specify the sequence of instructions needed for an inferior function
+call.
+
+Should be deprecated in favor of a macro that uses target-byte-ordered
+data.
+
+@item SIZEOF_CALL_DUMMY_WORDS
+@findex SIZEOF_CALL_DUMMY_WORDS
+The size of @code{CALL_DUMMY_WORDS}. When @code{CALL_DUMMY_P} this must
+return a positive value. See also @code{CALL_DUMMY_LENGTH}.
+
@item CALL_DUMMY
-valops.c
+@findex CALL_DUMMY
+A static initializer for @code{CALL_DUMMY_WORDS}. Deprecated.
+
@item CALL_DUMMY_LOCATION
-inferior.h
+@findex CALL_DUMMY_LOCATION
+See the file @file{inferior.h}.
+
@item CALL_DUMMY_STACK_ADJUST
-valops.c
-@item CANNOT_FETCH_REGISTER
-hppabsd-xdep.c
-@item CANNOT_STORE_REGISTER
-findvar.c
-@item CFRONT_PRODUCER
-dwarfread.c
-@item CHILD_PREPARE_TO_STORE
-inftarg.c
-@item CLEAR_DEFERRED_STORES
-inflow.c
-@item CLEAR_SOLIB
-objfiles.c
-@item COFF_ENCAPSULATE
-hppabsd-tdep.c
-@item COFF_FORMAT
-symm-tdep.c
-@item CORE_NEEDS_RELOCATION
-stack.c
+@findex CALL_DUMMY_STACK_ADJUST
+Stack adjustment needed when performing an inferior function call.
+
+Should be deprecated in favor of something like @code{STACK_ALIGN}.
+
+@item CALL_DUMMY_STACK_ADJUST_P
+@findex CALL_DUMMY_STACK_ADJUST_P
+Predicate for use of @code{CALL_DUMMY_STACK_ADJUST}.
+
+Should be deprecated in favor of something like @code{STACK_ALIGN}.
+
+@item CANNOT_FETCH_REGISTER (@var{regno})
+@findex CANNOT_FETCH_REGISTER
+A C expression that should be nonzero if @var{regno} cannot be fetched
+from an inferior process. This is only relevant if
+@code{FETCH_INFERIOR_REGISTERS} is not defined.
+
+@item CANNOT_STORE_REGISTER (@var{regno})
+@findex CANNOT_STORE_REGISTER
+A C expression that should be nonzero if @var{regno} should not be
+written to the target. This is often the case for program counters,
+status words, and other special registers. If this is not defined,
+@value{GDBN} will assume that all registers may be written.
+
+@item DO_DEFERRED_STORES
+@itemx CLEAR_DEFERRED_STORES
+@findex CLEAR_DEFERRED_STORES
+@findex DO_DEFERRED_STORES
+Define this to execute any deferred stores of registers into the inferior,
+and to cancel any deferred stores.
+
+Currently only implemented correctly for native Sparc configurations?
+
+@item COERCE_FLOAT_TO_DOUBLE (@var{formal}, @var{actual})
+@findex COERCE_FLOAT_TO_DOUBLE
+@cindex promotion to @code{double}
+@cindex @code{float} arguments
+@cindex prototyped functions, passing arguments to
+@cindex passing arguments to prototyped functions
+Return non-zero if GDB should promote @code{float} values to
+@code{double} when calling a non-prototyped function. The argument
+@var{actual} is the type of the value we want to pass to the function.
+The argument @var{formal} is the type of this argument, as it appears in
+the function's definition. Note that @var{formal} may be zero if we
+have no debugging information for the function, or if we're passing more
+arguments than are officially declared (for example, varargs). This
+macro is never invoked if the function definitely has a prototype.
+
+How you should pass arguments to a function depends on whether it was
+defined in K&R style or prototype style. If you define a function using
+the K&R syntax that takes a @code{float} argument, then callers must
+pass that argument as a @code{double}. If you define the function using
+the prototype syntax, then you must pass the argument as a @code{float},
+with no promotion.
+
+Unfortunately, on certain older platforms, the debug info doesn't
+indicate reliably how each function was defined. A function type's
+@code{TYPE_FLAG_PROTOTYPED} flag may be unset, even if the function was
+defined in prototype style. When calling a function whose
+@code{TYPE_FLAG_PROTOTYPED} flag is unset, GDB consults the
+@code{COERCE_FLOAT_TO_DOUBLE} macro to decide what to do.
+
+@findex standard_coerce_float_to_double
+For modern targets, it is proper to assume that, if the prototype flag
+is unset, that can be trusted: @code{float} arguments should be promoted
+to @code{double}. You should use the function
+@code{standard_coerce_float_to_double} to get this behavior.
+
+@findex default_coerce_float_to_double
+For some older targets, if the prototype flag is unset, that doesn't
+tell us anything. So we guess that, if we don't have a type for the
+formal parameter (@i{i.e.}, the first argument to
+@code{COERCE_FLOAT_TO_DOUBLE} is null), then we should promote it;
+otherwise, we should leave it alone. The function
+@code{default_coerce_float_to_double} provides this behavior; it is the
+default value, for compatibility with older configurations.
+
@item CPLUS_MARKER
-cplus-dem.c
-@item CREATE_INFERIOR_HOOK
-infrun.c
-@item C_ALLOCA
-regex.c
-@item C_GLBLREG
-coffread.c
-@item DBXREAD_ONLY
-partial-stab.h
+@findex CPLUS_MARKERz
+Define this to expand into the character that G@t{++} uses to distinguish
+compiler-generated identifiers from programmer-specified identifiers.
+By default, this expands into @code{'$'}. Most System V targets should
+define this to @code{'.'}.
+
@item DBX_PARM_SYMBOL_CLASS
-stabsread.c
-@item DEBUG
-remote-adapt.c
-@item DEBUG_INFO
-partial-stab.h
-@item DEBUG_PTRACE
-hppabsd-xdep.c
+@findex DBX_PARM_SYMBOL_CLASS
+Hook for the @code{SYMBOL_CLASS} of a parameter when decoding DBX symbol
+information. In the i960, parameters can be stored as locals or as
+args, depending on the type of the debug record.
+
@item DECR_PC_AFTER_BREAK
-breakpoint.c
-@item DEFAULT_PROMPT
-main.c
-@item DELTA88
-m88k-xdep.c
-@item DEV_TTY
-symmisc.c
-@item DGUX
-m88k-xdep.c
-@item DISABLE_UNSETTABLE_BREAK
-breakpoint.c
-@item DONT_USE_REMOTE
-remote.c
-@item DO_DEFERRED_STORES
-infrun.c
+@findex DECR_PC_AFTER_BREAK
+Define this to be the amount by which to decrement the PC after the
+program encounters a breakpoint. This is often the number of bytes in
+@code{BREAKPOINT}, though not always. For most targets this value will be 0.
+
+@item DECR_PC_AFTER_HW_BREAK
+@findex DECR_PC_AFTER_HW_BREAK
+Similarly, for hardware breakpoints.
+
+@item DISABLE_UNSETTABLE_BREAK (@var{addr})
+@findex DISABLE_UNSETTABLE_BREAK
+If defined, this should evaluate to 1 if @var{addr} is in a shared
+library in which breakpoints cannot be set and so should be disabled.
+
@item DO_REGISTERS_INFO
-infcmd.c
+@findex DO_REGISTERS_INFO
+If defined, use this to print the value of a register or all registers.
+
+@item DWARF_REG_TO_REGNUM
+@findex DWARF_REG_TO_REGNUM
+Convert DWARF register number into @value{GDBN} regnum. If not defined,
+no conversion will be performed.
+
+@item DWARF2_REG_TO_REGNUM
+@findex DWARF2_REG_TO_REGNUM
+Convert DWARF2 register number into @value{GDBN} regnum. If not
+defined, no conversion will be performed.
+
+@item ECOFF_REG_TO_REGNUM
+@findex ECOFF_REG_TO_REGNUM
+Convert ECOFF register number into @value{GDBN} regnum. If not defined,
+no conversion will be performed.
+
@item END_OF_TEXT_DEFAULT
-dbxread.c
-@item EXTERN
-buildsym.h
-@item EXTRACT_RETURN_VALUE
-tm-m68k.h
-@item EXTRACT_STRUCT_VALUE_ADDRESS
-values.c
-@item EXTRA_FRAME_INFO
-frame.h
-@item EXTRA_SYMTAB_INFO
-symtab.h
-@item FILES_INFO_HOOK
-target.c
-@item FIXME
-coffread.c
+@findex END_OF_TEXT_DEFAULT
+This is an expression that should designate the end of the text section.
+@c (? FIXME ?)
+
+@item EXTRACT_RETURN_VALUE(@var{type}, @var{regbuf}, @var{valbuf})
+@findex EXTRACT_RETURN_VALUE
+Define this to extract a function's return value of type @var{type} from
+the raw register state @var{regbuf} and copy that, in virtual format,
+into @var{valbuf}.
+
+@item EXTRACT_STRUCT_VALUE_ADDRESS(@var{regbuf})
+@findex EXTRACT_STRUCT_VALUE_ADDRESS
+When defined, extract from the array @var{regbuf} (containing the raw
+register state) the @code{CORE_ADDR} at which a function should return
+its structure value.
+
+If not defined, @code{EXTRACT_RETURN_VALUE} is used.
+
+@item EXTRACT_STRUCT_VALUE_ADDRESS_P()
+@findex EXTRACT_STRUCT_VALUE_ADDRESS_P
+Predicate for @code{EXTRACT_STRUCT_VALUE_ADDRESS}.
+
@item FLOAT_INFO
-infcmd.c
-@item FOPEN_RB
-defs.h
-@item FP0_REGNUM
-a68v-xdep.c
-@item FPC_REGNUM
-mach386-xdep.c
+@findex FLOAT_INFO
+If defined, then the @samp{info float} command will print information about
+the processor's floating point unit.
+
@item FP_REGNUM
-parse.c
-@item FPU
-Unused? 6-oct-92 rich@@cygnus.com. FIXME.
-@item FRAMELESS_FUNCTION_INVOCATION
-blockframe.c
-@item FRAME_ARGS_ADDRESS_CORRECT
-stack.c
-@item FRAME_CHAIN
-Given FRAME, return a pointer to the calling frame.
-@item FRAME_CHAIN_COMBINE
-blockframe.c
-@item FRAME_CHAIN_VALID
-frame.h
-@item FRAME_CHAIN_VALID_ALTERNATE
-frame.h
-@item FRAME_FIND_SAVED_REGS
-stack.c
-@item FRAME_GET_BASEREG_VALUE
-frame.h
-@item FRAME_NUM_ARGS
-tm-m68k.h
-@item FRAME_SPECIFICATION_DYADIC
-stack.c
-@item FRAME_SAVED_PC
-Given FRAME, return the pc saved there. That is, the return address.
-@item FUNCTION_EPILOGUE_SIZE
-coffread.c
-@item F_OK
-xm-ultra3.h
-@item GCC2_COMPILED_FLAG_SYMBOL
-dbxread.c
+@findex FP_REGNUM
+If the virtual frame pointer is kept in a register, then define this
+macro to be the number (greater than or equal to zero) of that register.
+
+This should only need to be defined if @code{TARGET_READ_FP} and
+@code{TARGET_WRITE_FP} are not defined.
+
+@item FRAMELESS_FUNCTION_INVOCATION(@var{fi})
+@findex FRAMELESS_FUNCTION_INVOCATION
+Define this to an expression that returns 1 if the function invocation
+represented by @var{fi} does not have a stack frame associated with it.
+Otherwise return 0.
+
+@item FRAME_ARGS_ADDRESS_CORRECT
+@findex FRAME_ARGS_ADDRESS_CORRECT
+See @file{stack.c}.
+
+@item FRAME_CHAIN(@var{frame})
+@findex FRAME_CHAIN
+Given @var{frame}, return a pointer to the calling frame.
+
+@item FRAME_CHAIN_COMBINE(@var{chain}, @var{frame})
+@findex FRAME_CHAIN_COMBINE
+Define this to take the frame chain pointer and the frame's nominal
+address and produce the nominal address of the caller's frame.
+Presently only defined for HP PA.
+
+@item FRAME_CHAIN_VALID(@var{chain}, @var{thisframe})
+@findex FRAME_CHAIN_VALID
+Define this to be an expression that returns zero if the given frame is
+an outermost frame, with no caller, and nonzero otherwise. Several
+common definitions are available:
+
+@itemize @bullet
+@item
+@code{file_frame_chain_valid} is nonzero if the chain pointer is nonzero
+and given frame's PC is not inside the startup file (such as
+@file{crt0.o}).
+
+@item
+@code{func_frame_chain_valid} is nonzero if the chain
+pointer is nonzero and the given frame's PC is not in @code{main} or a
+known entry point function (such as @code{_start}).
+
+@item
+@code{generic_file_frame_chain_valid} and
+@code{generic_func_frame_chain_valid} are equivalent implementations for
+targets using generic dummy frames.
+@end itemize
+
+@item FRAME_INIT_SAVED_REGS(@var{frame})
+@findex FRAME_INIT_SAVED_REGS
+See @file{frame.h}. Determines the address of all registers in the
+current stack frame storing each in @code{frame->saved_regs}. Space for
+@code{frame->saved_regs} shall be allocated by
+@code{FRAME_INIT_SAVED_REGS} using either
+@code{frame_saved_regs_zalloc} or @code{frame_obstack_alloc}.
+
+@code{FRAME_FIND_SAVED_REGS} and @code{EXTRA_FRAME_INFO} are deprecated.
+
+@item FRAME_NUM_ARGS (@var{fi})
+@findex FRAME_NUM_ARGS
+For the frame described by @var{fi} return the number of arguments that
+are being passed. If the number of arguments is not known, return
+@code{-1}.
+
+@item FRAME_SAVED_PC(@var{frame})
+@findex FRAME_SAVED_PC
+Given @var{frame}, return the pc saved there. This is the return
+address.
+
+@item FUNCTION_EPILOGUE_SIZE
+@findex FUNCTION_EPILOGUE_SIZE
+For some COFF targets, the @code{x_sym.x_misc.x_fsize} field of the
+function end symbol is 0. For such targets, you must define
+@code{FUNCTION_EPILOGUE_SIZE} to expand into the standard size of a
+function's epilogue.
+
+@item FUNCTION_START_OFFSET
+@findex FUNCTION_START_OFFSET
+An integer, giving the offset in bytes from a function's address (as
+used in the values of symbols, function pointers, etc.), and the
+function's first genuine instruction.
+
+This is zero on almost all machines: the function's address is usually
+the address of its first instruction. However, on the VAX, for example,
+each function starts with two bytes containing a bitmask indicating
+which registers to save upon entry to the function. The VAX @code{call}
+instructions check this value, and save the appropriate registers
+automatically. Thus, since the offset from the function's address to
+its first instruction is two bytes, @code{FUNCTION_START_OFFSET} would
+be 2 on the VAX.
+
@item GCC_COMPILED_FLAG_SYMBOL
-dbxread.c
-@item GCC_MANGLE_BUG
-symtab.c
-@item GCC_PRODUCER
-dwarfread.c
-@item GDB_TARGET_IS_HPPA
-This determines whether horrible kludge code in dbxread.c and partial-stab.h
-is used to mangle multiple-symbol-table files from HPPA's. This should all
-be ripped out, and a scheme like elfread.c used.
-@item GDB_TARGET_IS_MACH386
-mach386-xdep.c
-@item GDB_TARGET_IS_SUN3
-a68v-xdep.c
-@item GDB_TARGET_IS_SUN386
-sun386-xdep.c
+@itemx GCC2_COMPILED_FLAG_SYMBOL
+@findex GCC2_COMPILED_FLAG_SYMBOL
+@findex GCC_COMPILED_FLAG_SYMBOL
+If defined, these are the names of the symbols that @value{GDBN} will
+look for to detect that GCC compiled the file. The default symbols
+are @code{gcc_compiled.} and @code{gcc2_compiled.},
+respectively. (Currently only defined for the Delta 68.)
+
+@item @value{GDBN}_MULTI_ARCH
+@findex @value{GDBN}_MULTI_ARCH
+If defined and non-zero, enables suport for multiple architectures
+within @value{GDBN}.
+
+This support can be enabled at two levels. At level one, only
+definitions for previously undefined macros are provided; at level two,
+a multi-arch definition of all architecture dependant macros will be
+defined.
+
+@item @value{GDBN}_TARGET_IS_HPPA
+@findex @value{GDBN}_TARGET_IS_HPPA
+This determines whether horrible kludge code in @file{dbxread.c} and
+@file{partial-stab.h} is used to mangle multiple-symbol-table files from
+HPPA's. This should all be ripped out, and a scheme like @file{elfread.c}
+used instead.
+
@item GET_LONGJMP_TARGET
-For most machines, this is a target-dependent parameter. On the DECstation
-and the Iris, this is a native-dependent parameter, since <setjmp.h> is
-needed to define it.
-
-This macro determines the target PC address that longjmp() will jump
-to, assuming that we have just stopped at a longjmp breakpoint. It
-takes a CORE_ADDR * as argument, and stores the target PC value through
-this pointer. It examines the current state of the machine as needed.
+@findex GET_LONGJMP_TARGET
+For most machines, this is a target-dependent parameter. On the
+DECstation and the Iris, this is a native-dependent parameter, since
+trhe header file @file{setjmp.h} is needed to define it.
+
+This macro determines the target PC address that @code{longjmp} will jump to,
+assuming that we have just stopped at a @code{longjmp} breakpoint. It takes a
+@code{CORE_ADDR *} as argument, and stores the target PC value through this
+pointer. It examines the current state of the machine as needed.
+
@item GET_SAVED_REGISTER
-findvar.c
-@item GPLUS_PRODUCER
-dwarfread.c
-@item GR64_REGNUM
-remote-adapt.c
-@item GR64_REGNUM
-remote-mm.c
-@item HANDLE_RBRAC
-partial-stab.h
-@item HAVE_68881
-m68k-tdep.c
+@findex GET_SAVED_REGISTER
+@findex get_saved_register
+Define this if you need to supply your own definition for the function
+@code{get_saved_register}.
+
@item HAVE_REGISTER_WINDOWS
-findvar.c
-@item HAVE_SIGSETMASK
-main.c
-@item HAVE_TERMIO
-inflow.c
-@item HEADER_SEEK_FD
-arm-tdep.c
-@item HOSTING_ONLY
-xm-rtbsd.h
-@item HOST_BYTE_ORDER
-ieee-float.c
-@item HPUX_ASM
-xm-hp300hpux.h
-@item HPUX_VERSION_5
-hp300ux-xdep.c
-@item HP_OS_BUG
-infrun.c
-@item I80960
-remote-vx.c
+@findex HAVE_REGISTER_WINDOWS
+Define this if the target has register windows.
+
+@item REGISTER_IN_WINDOW_P (@var{regnum})
+@findex REGISTER_IN_WINDOW_P
+Define this to be an expression that is 1 if the given register is in
+the window.
+
@item IBM6000_TARGET
-Shows that we are configured for an IBM RS/6000 target. This conditional
-should be eliminated (FIXME) and replaced by feature-specific macros.
-It was introduced in haste and we are repenting at leisure.
-@item IEEE_DEBUG
-ieee-float.c
+@findex IBM6000_TARGET
+Shows that we are configured for an IBM RS/6000 target. This
+conditional should be eliminated (FIXME) and replaced by
+feature-specific macros. It was introduced in a haste and we are
+repenting at leisure.
+
+@item I386_USE_GENERIC_WATCHPOINTS
+An x86-based target can define this to use the generic x86 watchpoint
+support; see @ref{Algorithms, I386_USE_GENERIC_WATCHPOINTS}.
+
+@item SYMBOLS_CAN_START_WITH_DOLLAR
+@findex SYMBOLS_CAN_START_WITH_DOLLAR
+Some systems have routines whose names start with @samp{$}. Giving this
+macro a non-zero value tells @value{GDBN}'s expression parser to check for such
+routines when parsing tokens that begin with @samp{$}.
+
+On HP-UX, certain system routines (millicode) have names beginning with
+@samp{$} or @samp{$$}. For example, @code{$$dyncall} is a millicode
+routine that handles inter-space procedure calls on PA-RISC.
+
@item IEEE_FLOAT
-valprint.c
-@item IGNORE_SYMBOL
-dbxread.c
-@item INIT_EXTRA_FRAME_INFO
-blockframe.c
-@item INIT_EXTRA_SYMTAB_INFO
-symfile.c
-@item INIT_FRAME_PC
-blockframe.c
-@item INNER_THAN
-valops.c
-@item INT_MAX
-defs.h
-@item INT_MIN
-defs.h
-@item IN_GDB
-i960-pinsn.c
-@item IN_SIGTRAMP
-infrun.c
-@item IN_SOLIB_TRAMPOLINE
-infrun.c
-@item ISATTY
-main.c
-@item IS_TRAPPED_INTERNALVAR
-values.c
-@item KERNELDEBUG
-dbxread.c
-@item KERNEL_DEBUGGING
-tm-ultra3.h
-@item LCC_PRODUCER
-dwarfread.c
-@item LITTLE_ENDIAN
-defs.h
-@item LOG_FILE
-remote-adapt.c
-@item LONGERNAMES
-cplus-dem.c
-@item LONGEST
-defs.h
-@item LONG_LONG
-defs.h
-@item LONG_MAX
-defs.h
-@item L_LNNO32
-coffread.c
-@item MACHKERNELDEBUG
-hppabsd-tdep.c
-@item MAIN
-cplus-dem.c
-@item MAINTENANCE
-dwarfread.c
-@item MAINTENANCE_CMDS
-breakpoint.c
-@item MAINTENANCE_CMDS
-maint.c
-@item MIPSEL
-mips-tdep.c
-@item MOTOROLA
-xm-altos.h
-@item NBPG
-altos-xdep.c
-@item NEED_POSIX_SETPGID
-infrun.c
+@findex IEEE_FLOAT
+Define this if the target system uses IEEE-format floating point numbers.
+
+@item INIT_EXTRA_FRAME_INFO (@var{fromleaf}, @var{frame})
+@findex INIT_EXTRA_FRAME_INFO
+If additional information about the frame is required this should be
+stored in @code{frame->extra_info}. Space for @code{frame->extra_info}
+is allocated using @code{frame_obstack_alloc}.
+
+@item INIT_FRAME_PC (@var{fromleaf}, @var{prev})
+@findex INIT_FRAME_PC
+This is a C statement that sets the pc of the frame pointed to by
+@var{prev}. [By default...]
+
+@item INNER_THAN (@var{lhs}, @var{rhs})
+@findex INNER_THAN
+Returns non-zero if stack address @var{lhs} is inner than (nearer to the
+stack top) stack address @var{rhs}. Define this as @code{lhs < rhs} if
+the target's stack grows downward in memory, or @code{lhs > rsh} if the
+stack grows upward.
+
+@item gdbarch_in_function_epilogue_p (@var{gdbarch}, @var{pc})
+@findex gdbarch_in_function_epilogue_p
+Returns non-zero if the given @var{pc} is in the epilogue of a function.
+The epilogue of a function is defined as the part of a function where
+the stack frame of the function already has been destroyed up to the
+final `return from function call' instruction.
+
+@item IN_SIGTRAMP (@var{pc}, @var{name})
+@findex IN_SIGTRAMP
+Define this to return non-zero if the given @var{pc} and/or @var{name}
+indicates that the current function is a @code{sigtramp}.
+
+@item SIGTRAMP_START (@var{pc})
+@findex SIGTRAMP_START
+@itemx SIGTRAMP_END (@var{pc})
+@findex SIGTRAMP_END
+Define these to be the start and end address of the @code{sigtramp} for the
+given @var{pc}. On machines where the address is just a compile time
+constant, the macro expansion will typically just ignore the supplied
+@var{pc}.
+
+@item IN_SOLIB_CALL_TRAMPOLINE (@var{pc}, @var{name})
+@findex IN_SOLIB_CALL_TRAMPOLINE
+Define this to evaluate to nonzero if the program is stopped in the
+trampoline that connects to a shared library.
+
+@item IN_SOLIB_RETURN_TRAMPOLINE (@var{pc}, @var{name})
+@findex IN_SOLIB_RETURN_TRAMPOLINE
+Define this to evaluate to nonzero if the program is stopped in the
+trampoline that returns from a shared library.
+
+@item IN_SOLIB_DYNSYM_RESOLVE_CODE (@var{pc})
+@findex IN_SOLIB_DYNSYM_RESOLVE_CODE
+Define this to evaluate to nonzero if the program is stopped in the
+dynamic linker.
+
+@item SKIP_SOLIB_RESOLVER (@var{pc})
+@findex SKIP_SOLIB_RESOLVER
+Define this to evaluate to the (nonzero) address at which execution
+should continue to get past the dynamic linker's symbol resolution
+function. A zero value indicates that it is not important or necessary
+to set a breakpoint to get through the dynamic linker and that single
+stepping will suffice.
+
+@item INTEGER_TO_ADDRESS (@var{type}, @var{buf})
+@findex INTEGER_TO_ADDRESS
+@cindex converting integers to addresses
+Define this when the architecture needs to handle non-pointer to address
+conversions specially. Converts that value to an address according to
+the current architectures conventions.
+
+@emph{Pragmatics: When the user copies a well defined expression from
+their source code and passes it, as a parameter, to @value{GDBN}'s
+@code{print} command, they should get the same value as would have been
+computed by the target program. Any deviation from this rule can cause
+major confusion and annoyance, and needs to be justified carefully. In
+other words, @value{GDBN} doesn't really have the freedom to do these
+conversions in clever and useful ways. It has, however, been pointed
+out that users aren't complaining about how @value{GDBN} casts integers
+to pointers; they are complaining that they can't take an address from a
+disassembly listing and give it to @code{x/i}. Adding an architecture
+method like @code{INTEGER_TO_ADDRESS} certainly makes it possible for
+@value{GDBN} to ``get it right'' in all circumstances.}
+
+@xref{Target Architecture Definition, , Pointers Are Not Always
+Addresses}.
+
+@item IS_TRAPPED_INTERNALVAR (@var{name})
+@findex IS_TRAPPED_INTERNALVAR
+This is an ugly hook to allow the specification of special actions that
+should occur as a side-effect of setting the value of a variable
+internal to @value{GDBN}. Currently only used by the h8500. Note that this
+could be either a host or target conditional.
+
@item NEED_TEXT_START_END
-exec.c
-@item NFAILURES
-regex.c
-@item NNPC_REGNUM
-infrun.c
-@item NORETURN
-defs.h
-@item NOTDEF
-regex.c
-@item NOTDEF
-remote-adapt.c
-@item NOTDEF
-remote-mm.c
-@item NOTICE_SIGNAL_HANDLING_CHANGE
-infrun.c
+@findex NEED_TEXT_START_END
+Define this if @value{GDBN} should determine the start and end addresses of the
+text section. (Seems dubious.)
+
@item NO_HIF_SUPPORT
-remote-mm.c
-@item NO_SIGINTERRUPT
-remote-adapt.c
-@item NO_SINGLE_STEP
-infptrace.c
-@item NO_TYPEDEFS
-xcoffread.c--This causes types not to be read, to save memory and speed
-things up.
-@item NPC_REGNUM
-infcmd.c
-@item NS32K_SVC_IMMED_OPERANDS
-ns32k-opcode.h
-@item NUMERIC_REG_NAMES
-mips-tdep.c
-@item N_SETV
-dbxread.c
-@item N_SET_MAGIC
-hppabsd-tdep.c
-@item NaN
-tm-umax.h
-@item ONE_PROCESS_WRITETEXT
-breakpoint.c
-@item PC
-convx-opcode.h
+@findex NO_HIF_SUPPORT
+(Specific to the a29k.)
+
+@item POINTER_TO_ADDRESS (@var{type}, @var{buf})
+@findex POINTER_TO_ADDRESS
+Assume that @var{buf} holds a pointer of type @var{type}, in the
+appropriate format for the current architecture. Return the byte
+address the pointer refers to.
+@xref{Target Architecture Definition, , Pointers Are Not Always Addresses}.
+
+@item REGISTER_CONVERTIBLE (@var{reg})
+@findex REGISTER_CONVERTIBLE
+Return non-zero if @var{reg} uses different raw and virtual formats.
+@xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}.
+
+@item REGISTER_RAW_SIZE (@var{reg})
+@findex REGISTER_RAW_SIZE
+Return the raw size of @var{reg}.
+@xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}.
+
+@item REGISTER_VIRTUAL_SIZE (@var{reg})
+@findex REGISTER_VIRTUAL_SIZE
+Return the virtual size of @var{reg}.
+@xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}.
+
+@item REGISTER_VIRTUAL_TYPE (@var{reg})
+@findex REGISTER_VIRTUAL_TYPE
+Return the virtual type of @var{reg}.
+@xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}.
+
+@item REGISTER_CONVERT_TO_VIRTUAL(@var{reg}, @var{type}, @var{from}, @var{to})
+@findex REGISTER_CONVERT_TO_VIRTUAL
+Convert the value of register @var{reg} from its raw form to its virtual
+form.
+@xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}.
+
+@item REGISTER_CONVERT_TO_RAW(@var{type}, @var{reg}, @var{from}, @var{to})
+@findex REGISTER_CONVERT_TO_RAW
+Convert the value of register @var{reg} from its virtual form to its raw
+form.
+@xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}.
+
+@item RETURN_VALUE_ON_STACK(@var{type})
+@findex RETURN_VALUE_ON_STACK
+@cindex returning structures by value
+@cindex structures, returning by value
+
+Return non-zero if values of type TYPE are returned on the stack, using
+the ``struct convention'' (i.e., the caller provides a pointer to a
+buffer in which the callee should store the return value). This
+controls how the @samp{finish} command finds a function's return value,
+and whether an inferior function call reserves space on the stack for
+the return value.
+
+The full logic @value{GDBN} uses here is kind of odd.
+
+@itemize @bullet
+@item
+If the type being returned by value is not a structure, union, or array,
+and @code{RETURN_VALUE_ON_STACK} returns zero, then @value{GDBN}
+concludes the value is not returned using the struct convention.
+
+@item
+Otherwise, @value{GDBN} calls @code{USE_STRUCT_CONVENTION} (see below).
+If that returns non-zero, @value{GDBN} assumes the struct convention is
+in use.
+@end itemize
+
+In other words, to indicate that a given type is returned by value using
+the struct convention, that type must be either a struct, union, array,
+or something @code{RETURN_VALUE_ON_STACK} likes, @emph{and} something
+that @code{USE_STRUCT_CONVENTION} likes.
+
+Note that, in C and C@t{++}, arrays are never returned by value. In those
+languages, these predicates will always see a pointer type, never an
+array type. All the references above to arrays being returned by value
+apply only to other languages.
+
+@item SOFTWARE_SINGLE_STEP_P()
+@findex SOFTWARE_SINGLE_STEP_P
+Define this as 1 if the target does not have a hardware single-step
+mechanism. The macro @code{SOFTWARE_SINGLE_STEP} must also be defined.
+
+@item SOFTWARE_SINGLE_STEP(@var{signal}, @var{insert_breapoints_p})
+@findex SOFTWARE_SINGLE_STEP
+A function that inserts or removes (depending on
+@var{insert_breapoints_p}) breakpoints at each possible destinations of
+the next instruction. See @file{sparc-tdep.c} and @file{rs6000-tdep.c}
+for examples.
+
+@item SOFUN_ADDRESS_MAYBE_MISSING
+@findex SOFUN_ADDRESS_MAYBE_MISSING
+Somebody clever observed that, the more actual addresses you have in the
+debug information, the more time the linker has to spend relocating
+them. So whenever there's some other way the debugger could find the
+address it needs, you should omit it from the debug info, to make
+linking faster.
+
+@code{SOFUN_ADDRESS_MAYBE_MISSING} indicates that a particular set of
+hacks of this sort are in use, affecting @code{N_SO} and @code{N_FUN}
+entries in stabs-format debugging information. @code{N_SO} stabs mark
+the beginning and ending addresses of compilation units in the text
+segment. @code{N_FUN} stabs mark the starts and ends of functions.
+
+@code{SOFUN_ADDRESS_MAYBE_MISSING} means two things:
+
+@itemize @bullet
+@item
+@code{N_FUN} stabs have an address of zero. Instead, you should find the
+addresses where the function starts by taking the function name from
+the stab, and then looking that up in the minsyms (the
+linker/assembler symbol table). In other words, the stab has the
+name, and the linker/assembler symbol table is the only place that carries
+the address.
+
+@item
+@code{N_SO} stabs have an address of zero, too. You just look at the
+@code{N_FUN} stabs that appear before and after the @code{N_SO} stab,
+and guess the starting and ending addresses of the compilation unit from
+them.
+@end itemize
+
@item PCC_SOL_BROKEN
-dbxread.c
+@findex PCC_SOL_BROKEN
+(Used only in the Convex target.)
+
@item PC_IN_CALL_DUMMY
-inferior.h
+@findex PC_IN_CALL_DUMMY
+See @file{inferior.h}.
+
@item PC_LOAD_SEGMENT
-stack.c
+@findex PC_LOAD_SEGMENT
+If defined, print information about the load segment for the program
+counter. (Defined only for the RS/6000.)
+
@item PC_REGNUM
-parse.c
-@item PRINT_RANDOM_SIGNAL
-infcmd.c
-@item PRINT_REGISTER_HOOK
-infcmd.c
+@findex PC_REGNUM
+If the program counter is kept in a register, then define this macro to
+be the number (greater than or equal to zero) of that register.
+
+This should only need to be defined if @code{TARGET_READ_PC} and
+@code{TARGET_WRITE_PC} are not defined.
+
+@item NPC_REGNUM
+@findex NPC_REGNUM
+The number of the ``next program counter'' register, if defined.
+
+@item NNPC_REGNUM
+@findex NNPC_REGNUM
+The number of the ``next next program counter'' register, if defined.
+Currently, this is only defined for the Motorola 88K.
+
+@item PARM_BOUNDARY
+@findex PARM_BOUNDARY
+If non-zero, round arguments to a boundary of this many bits before
+pushing them on the stack.
+
+@item PRINT_REGISTER_HOOK (@var{regno})
+@findex PRINT_REGISTER_HOOK
+If defined, this must be a function that prints the contents of the
+given register to standard output.
+
@item PRINT_TYPELESS_INTEGER
-valprint.c
+@findex PRINT_TYPELESS_INTEGER
+This is an obscure substitute for @code{print_longest} that seems to
+have been defined for the Convex target.
+
@item PROCESS_LINENUMBER_HOOK
-buildsym.c
+@findex PROCESS_LINENUMBER_HOOK
+A hook defined for XCOFF reading.
+
@item PROLOGUE_FIRSTLINE_OVERLAP
-infrun.c
-@item PSIGNAL_IN_SIGNAL_H
-defs.h
+@findex PROLOGUE_FIRSTLINE_OVERLAP
+(Only used in unsupported Convex configuration.)
+
@item PS_REGNUM
-parse.c
-@item PUSH_ARGUMENTS
-valops.c
+@findex PS_REGNUM
+If defined, this is the number of the processor status register. (This
+definition is only used in generic code when parsing "$ps".)
+
+@item POP_FRAME
+@findex POP_FRAME
+@findex call_function_by_hand
+@findex return_command
+Used in @samp{call_function_by_hand} to remove an artificial stack
+frame and in @samp{return_command} to remove a real stack frame.
+
+@item PUSH_ARGUMENTS (@var{nargs}, @var{args}, @var{sp}, @var{struct_return}, @var{struct_addr})
+@findex PUSH_ARGUMENTS
+Define this to push arguments onto the stack for inferior function
+call. Returns the updated stack pointer value.
+
+@item PUSH_DUMMY_FRAME
+@findex PUSH_DUMMY_FRAME
+Used in @samp{call_function_by_hand} to create an artificial stack frame.
+
@item REGISTER_BYTES
-remote.c
+@findex REGISTER_BYTES
+The total amount of space needed to store @value{GDBN}'s copy of the machine's
+register state.
+
+@item REGISTER_NAME(@var{i})
+@findex REGISTER_NAME
+Return the name of register @var{i} as a string. May return @code{NULL}
+or @code{NUL} to indicate that register @var{i} is not valid.
+
@item REGISTER_NAMES
-tm-a29k.h
-@item REG_STACK_SEGMENT
-exec.c
-@item REG_STRUCT_HAS_ADDR
-findvar.c
-@item RE_NREGS
-regex.h
-@item R_FP
-dwarfread.c
-@item R_OK
-xm-altos.h
+@findex REGISTER_NAMES
+Deprecated in favor of @code{REGISTER_NAME}.
+
+@item REG_STRUCT_HAS_ADDR (@var{gcc_p}, @var{type})
+@findex REG_STRUCT_HAS_ADDR
+Define this to return 1 if the given type will be passed by pointer
+rather than directly.
+
+@item SAVE_DUMMY_FRAME_TOS (@var{sp})
+@findex SAVE_DUMMY_FRAME_TOS
+Used in @samp{call_function_by_hand} to notify the target dependent code
+of the top-of-stack value that will be passed to the the inferior code.
+This is the value of the @code{SP} after both the dummy frame and space
+for parameters/results have been allocated on the stack.
+
@item SDB_REG_TO_REGNUM
-coffread.c
-@item SEEK_END
-state.c
-@item SEEK_SET
-state.c
-@item SEM
-coffread.c
-@item SHELL_COMMAND_CONCAT
-infrun.c
-@item SHELL_FILE
-infrun.c
+@findex SDB_REG_TO_REGNUM
+Define this to convert sdb register numbers into @value{GDBN} regnums. If not
+defined, no conversion will be done.
+
@item SHIFT_INST_REGS
-breakpoint.c
-@item SIGN_EXTEND_CHAR
-regex.c
-@item SIGTRAP_STOP_AFTER_LOAD
-infrun.c
-@item SKIP_PROLOGUE
-tm-m68k.h
+@findex SHIFT_INST_REGS
+(Only used for m88k targets.)
+
+@item SKIP_PERMANENT_BREAKPOINT
+@findex SKIP_PERMANENT_BREAKPOINT
+Advance the inferior's PC past a permanent breakpoint. @value{GDBN} normally
+steps over a breakpoint by removing it, stepping one instruction, and
+re-inserting the breakpoint. However, permanent breakpoints are
+hardwired into the inferior, and can't be removed, so this strategy
+doesn't work. Calling @code{SKIP_PERMANENT_BREAKPOINT} adjusts the processor's
+state so that execution will resume just after the breakpoint. This
+macro does the right thing even when the breakpoint is in the delay slot
+of a branch or jump.
+
+@item SKIP_PROLOGUE (@var{pc})
+@findex SKIP_PROLOGUE
+A C expression that returns the address of the ``real'' code beyond the
+function entry prologue found at @var{pc}.
+
@item SKIP_PROLOGUE_FRAMELESS_P
-blockframe.c
-@item SKIP_TRAMPOLINE_CODE
-infrun.c
-@item SOLIB_ADD
-core.c
-@item SOLIB_CREATE_INFERIOR_HOOK
-infrun.c
+@findex SKIP_PROLOGUE_FRAMELESS_P
+A C expression that should behave similarly, but that can stop as soon
+as the function is known to have a frame. If not defined,
+@code{SKIP_PROLOGUE} will be used instead.
+
+@item SKIP_TRAMPOLINE_CODE (@var{pc})
+@findex SKIP_TRAMPOLINE_CODE
+If the target machine has trampoline code that sits between callers and
+the functions being called, then define this macro to return a new PC
+that is at the start of the real function.
+
@item SP_REGNUM
-parse.c
+@findex SP_REGNUM
+If the stack-pointer is kept in a register, then define this macro to be
+the number (greater than or equal to zero) of that register.
+
+This should only need to be defined if @code{TARGET_WRITE_SP} and
+@code{TARGET_WRITE_SP} are not defined.
+
@item STAB_REG_TO_REGNUM
-stabsread.h
-@item STACK_ALIGN
-valops.c
-@item STACK_DIRECTION
-alloca.c
-@item START_INFERIOR_TRAPS_EXPECTED
-infrun.c
-@item STOP_SIGNAL
-main.c
-@item STORE_RETURN_VALUE
-tm-m68k.h
-@item SUN4_COMPILER_FEATURE
-infrun.c
+@findex STAB_REG_TO_REGNUM
+Define this to convert stab register numbers (as gotten from `r'
+declarations) into @value{GDBN} regnums. If not defined, no conversion will be
+done.
+
+@item STACK_ALIGN (@var{addr})
+@findex STACK_ALIGN
+Define this to adjust the address to the alignment required for the
+processor's stack.
+
+@item STEP_SKIPS_DELAY (@var{addr})
+@findex STEP_SKIPS_DELAY
+Define this to return true if the address is of an instruction with a
+delay slot. If a breakpoint has been placed in the instruction's delay
+slot, @value{GDBN} will single-step over that instruction before resuming
+normally. Currently only defined for the Mips.
+
+@item STORE_RETURN_VALUE (@var{type}, @var{valbuf})
+@findex STORE_RETURN_VALUE
+A C expression that stores a function return value of type @var{type},
+where @var{valbuf} is the address of the value to be stored.
+
@item SUN_FIXED_LBRAC_BUG
-dbxread.c
-@item SVR4_SHARED_LIBS
-solib.c
-@item SWITCH_ENUM_BUG
-regex.c
-@item SYM1
-tm-ultra3.h
+@findex SUN_FIXED_LBRAC_BUG
+(Used only for Sun-3 and Sun-4 targets.)
+
@item SYMBOL_RELOADING_DEFAULT
-symfile.c
-@item SYNTAX_TABLE
-regex.c
-@item Sword
-regex.c
-@item TARGET_BYTE_ORDER
-defs.h
+@findex SYMBOL_RELOADING_DEFAULT
+The default value of the ``symbol-reloading'' variable. (Never defined in
+current sources.)
+
+@item TARGET_BYTE_ORDER_DEFAULT
+@findex TARGET_BYTE_ORDER_DEFAULT
+The ordering of bytes in the target. This must be either
+@code{BIG_ENDIAN} or @code{BFD_ENDIAN_LITTLE}. This macro replaces
+@code{TARGET_BYTE_ORDER} which is deprecated.
+
+@item TARGET_BYTE_ORDER_SELECTABLE_P
+@findex TARGET_BYTE_ORDER_SELECTABLE_P
+Non-zero if the target has both @code{BIG_ENDIAN} and
+@code{BFD_ENDIAN_LITTLE} variants. This macro replaces
+@code{TARGET_BYTE_ORDER_SELECTABLE} which is deprecated.
+
@item TARGET_CHAR_BIT
-defs.h
+@findex TARGET_CHAR_BIT
+Number of bits in a char; defaults to 8.
+
@item TARGET_COMPLEX_BIT
-defs.h
+@findex TARGET_COMPLEX_BIT
+Number of bits in a complex number; defaults to @code{2 * TARGET_FLOAT_BIT}.
+
+At present this macro is not used.
+
@item TARGET_DOUBLE_BIT
-defs.h
+@findex TARGET_DOUBLE_BIT
+Number of bits in a double float; defaults to @code{8 * TARGET_CHAR_BIT}.
+
@item TARGET_DOUBLE_COMPLEX_BIT
-defs.h
+@findex TARGET_DOUBLE_COMPLEX_BIT
+Number of bits in a double complex; defaults to @code{2 * TARGET_DOUBLE_BIT}.
+
+At present this macro is not used.
+
@item TARGET_FLOAT_BIT
-defs.h
+@findex TARGET_FLOAT_BIT
+Number of bits in a float; defaults to @code{4 * TARGET_CHAR_BIT}.
+
@item TARGET_INT_BIT
-defs.h
+@findex TARGET_INT_BIT
+Number of bits in an integer; defaults to @code{4 * TARGET_CHAR_BIT}.
+
@item TARGET_LONG_BIT
-defs.h
+@findex TARGET_LONG_BIT
+Number of bits in a long integer; defaults to @code{4 * TARGET_CHAR_BIT}.
+
@item TARGET_LONG_DOUBLE_BIT
-defs.h
+@findex TARGET_LONG_DOUBLE_BIT
+Number of bits in a long double float;
+defaults to @code{2 * TARGET_DOUBLE_BIT}.
+
@item TARGET_LONG_LONG_BIT
-defs.h
+@findex TARGET_LONG_LONG_BIT
+Number of bits in a long long integer; defaults to @code{2 * TARGET_LONG_BIT}.
+
@item TARGET_PTR_BIT
-defs.h
+@findex TARGET_PTR_BIT
+Number of bits in a pointer; defaults to @code{TARGET_INT_BIT}.
+
@item TARGET_SHORT_BIT
-defs.h
-@item TDESC
-infrun.c
-@item TM_FILE_OVERRIDE
-defs.h
-@item T_ARG
-coffread.c
-@item T_VOID
-coffread.c
-@item UINT_MAX
-defs.h
-@item USER
-m88k-tdep.c
-@item USE_GAS
-xm-news.h
-@item USE_STRUCT_CONVENTION
-values.c
-@item USIZE
-xm-m88k.h
-@item U_FPSTATE
-i386-xdep.c
-@item VARIABLES_INSIDE_BLOCK
-dbxread.c
-@item WRS_ORIG
-remote-vx.c
-@item _LANG_c
-language.c
-@item _LANG_m2
-language.c
-@item __GO32__
-inflow.c
-@item __HAVE_68881__
-m68k-stub.c
-@item __HPUX_ASM__
-xm-hp300hpux.h
-@item __INT_VARARGS_H
-printcmd.c
-@item __not_on_pyr_yet
-pyr-xdep.c
-@item GOULD_PN
-gould-pinsn.c
-@item emacs
-alloca.c
-@item hp800
-xm-hppabsd.h
-@item hpux
-hppabsd-core.c
-@item longest_to_int
-defs.h
-@item mc68020
-m68k-stub.c
-@item ns32k_opcodeT
-ns32k-opcode.h
-@item sgi
-mips-tdep.c
-@item sparc
-regex.c
-@item static
-alloca.c
-@item sun
-m68k-tdep.c
-@item sun386
-tm-sun386.h
-@item test
-regex.c
-@item x_name
-coffread.c
-@item x_zeroes
-coffread.c
+@findex TARGET_SHORT_BIT
+Number of bits in a short integer; defaults to @code{2 * TARGET_CHAR_BIT}.
+
+@item TARGET_READ_PC
+@findex TARGET_READ_PC
+@itemx TARGET_WRITE_PC (@var{val}, @var{pid})
+@findex TARGET_WRITE_PC
+@itemx TARGET_READ_SP
+@findex TARGET_READ_SP
+@itemx TARGET_WRITE_SP
+@findex TARGET_WRITE_SP
+@itemx TARGET_READ_FP
+@findex TARGET_READ_FP
+@itemx TARGET_WRITE_FP
+@findex TARGET_WRITE_FP
+@findex read_pc
+@findex write_pc
+@findex read_sp
+@findex write_sp
+@findex read_fp
+@findex write_fp
+These change the behavior of @code{read_pc}, @code{write_pc},
+@code{read_sp}, @code{write_sp}, @code{read_fp} and @code{write_fp}.
+For most targets, these may be left undefined. @value{GDBN} will call the read
+and write register functions with the relevant @code{_REGNUM} argument.
+
+These macros are useful when a target keeps one of these registers in a
+hard to get at place; for example, part in a segment register and part
+in an ordinary register.
+
+@item TARGET_VIRTUAL_FRAME_POINTER(@var{pc}, @var{regp}, @var{offsetp})
+@findex TARGET_VIRTUAL_FRAME_POINTER
+Returns a @code{(register, offset)} pair representing the virtual
+frame pointer in use at the code address @var{pc}. If virtual
+frame pointers are not used, a default definition simply returns
+@code{FP_REGNUM}, with an offset of zero.
+
+@item TARGET_HAS_HARDWARE_WATCHPOINTS
+If non-zero, the target has support for hardware-assisted
+watchpoints. @xref{Algorithms, watchpoints}, for more details and
+other related macros.
+
+@item TARGET_PRINT_INSN (@var{addr}, @var{info})
+@findex TARGET_PRINT_INSN
+This is the function used by @value{GDBN} to print an assembly
+instruction. It prints the instruction at address @var{addr} in
+debugged memory and returns the length of the instruction, in bytes. If
+a target doesn't define its own printing routine, it defaults to an
+accessor function for the global pointer @code{tm_print_insn}. This
+usually points to a function in the @code{opcodes} library (@pxref{Support
+Libraries, ,Opcodes}). @var{info} is a structure (of type
+@code{disassemble_info}) defined in @file{include/dis-asm.h} used to
+pass information to the instruction decoding routine.
+
+@item USE_STRUCT_CONVENTION (@var{gcc_p}, @var{type})
+@findex USE_STRUCT_CONVENTION
+If defined, this must be an expression that is nonzero if a value of the
+given @var{type} being returned from a function must have space
+allocated for it on the stack. @var{gcc_p} is true if the function
+being considered is known to have been compiled by GCC; this is helpful
+for systems where GCC is known to use different calling convention than
+other compilers.
+
+@item VARIABLES_INSIDE_BLOCK (@var{desc}, @var{gcc_p})
+@findex VARIABLES_INSIDE_BLOCK
+For dbx-style debugging information, if the compiler puts variable
+declarations inside LBRAC/RBRAC blocks, this should be defined to be
+nonzero. @var{desc} is the value of @code{n_desc} from the
+@code{N_RBRAC} symbol, and @var{gcc_p} is true if @value{GDBN} has noticed the
+presence of either the @code{GCC_COMPILED_SYMBOL} or the
+@code{GCC2_COMPILED_SYMBOL}. By default, this is 0.
+
+@item OS9K_VARIABLES_INSIDE_BLOCK (@var{desc}, @var{gcc_p})
+@findex OS9K_VARIABLES_INSIDE_BLOCK
+Similarly, for OS/9000. Defaults to 1.
+@end table
+
+Motorola M68K target conditionals.
+
+@ftable @code
+@item BPT_VECTOR
+Define this to be the 4-bit location of the breakpoint trap vector. If
+not defined, it will default to @code{0xf}.
+
+@item REMOTE_BPT_VECTOR
+Defaults to @code{1}.
+@end ftable
+
+@section Adding a New Target
+
+@cindex adding a target
+The following files add a target to @value{GDBN}:
+
+@table @file
+@vindex TDEPFILES
+@item gdb/config/@var{arch}/@var{ttt}.mt
+Contains a Makefile fragment specific to this target. Specifies what
+object files are needed for target @var{ttt}, by defining
+@samp{TDEPFILES=@dots{}} and @samp{TDEPLIBS=@dots{}}. Also specifies
+the header file which describes @var{ttt}, by defining @samp{TM_FILE=
+tm-@var{ttt}.h}.
+
+You can also define @samp{TM_CFLAGS}, @samp{TM_CLIBS}, @samp{TM_CDEPS},
+but these are now deprecated, replaced by autoconf, and may go away in
+future versions of @value{GDBN}.
+
+@item gdb/@var{ttt}-tdep.c
+Contains any miscellaneous code required for this target machine. On
+some machines it doesn't exist at all. Sometimes the macros in
+@file{tm-@var{ttt}.h} become very complicated, so they are implemented
+as functions here instead, and the macro is simply defined to call the
+function. This is vastly preferable, since it is easier to understand
+and debug.
+
+@item gdb/@var{arch}-tdep.c
+@itemx gdb/@var{arch}-tdep.h
+This often exists to describe the basic layout of the target machine's
+processor chip (registers, stack, etc.). If used, it is included by
+@file{@var{ttt}-tdep.h}. It can be shared among many targets that use
+the same processor.
+
+@item gdb/config/@var{arch}/tm-@var{ttt}.h
+(@file{tm.h} is a link to this file, created by @code{configure}). Contains
+macro definitions about the target machine's registers, stack frame
+format and instructions.
+
+New targets do not need this file and should not create it.
+
+@item gdb/config/@var{arch}/tm-@var{arch}.h
+This often exists to describe the basic layout of the target machine's
+processor chip (registers, stack, etc.). If used, it is included by
+@file{tm-@var{ttt}.h}. It can be shared among many targets that use the
+same processor.
+
+New targets do not need this file and should not create it.
+
+@end table
+
+If you are adding a new operating system for an existing CPU chip, add a
+@file{config/tm-@var{os}.h} file that describes the operating system
+facilities that are unusual (extra symbol table info; the breakpoint
+instruction needed; etc.). Then write a @file{@var{arch}/tm-@var{os}.h}
+that just @code{#include}s @file{tm-@var{arch}.h} and
+@file{config/tm-@var{os}.h}.
+
+
+@node Target Vector Definition
+
+@chapter Target Vector Definition
+@cindex target vector
+
+The target vector defines the interface between @value{GDBN}'s
+abstract handling of target systems, and the nitty-gritty code that
+actually exercises control over a process or a serial port.
+@value{GDBN} includes some 30-40 different target vectors; however,
+each configuration of @value{GDBN} includes only a few of them.
+
+@section File Targets
+
+Both executables and core files have target vectors.
+
+@section Standard Protocol and Remote Stubs
+
+@value{GDBN}'s file @file{remote.c} talks a serial protocol to code
+that runs in the target system. @value{GDBN} provides several sample
+@dfn{stubs} that can be integrated into target programs or operating
+systems for this purpose; they are named @file{*-stub.c}.
+
+The @value{GDBN} user's manual describes how to put such a stub into
+your target code. What follows is a discussion of integrating the
+SPARC stub into a complicated operating system (rather than a simple
+program), by Stu Grossman, the author of this stub.
+
+The trap handling code in the stub assumes the following upon entry to
+@code{trap_low}:
+
+@enumerate
+@item
+%l1 and %l2 contain pc and npc respectively at the time of the trap;
+
+@item
+traps are disabled;
+
+@item
+you are in the correct trap window.
+@end enumerate
+
+As long as your trap handler can guarantee those conditions, then there
+is no reason why you shouldn't be able to ``share'' traps with the stub.
+The stub has no requirement that it be jumped to directly from the
+hardware trap vector. That is why it calls @code{exceptionHandler()},
+which is provided by the external environment. For instance, this could
+set up the hardware traps to actually execute code which calls the stub
+first, and then transfers to its own trap handler.
+
+For the most point, there probably won't be much of an issue with
+``sharing'' traps, as the traps we use are usually not used by the kernel,
+and often indicate unrecoverable error conditions. Anyway, this is all
+controlled by a table, and is trivial to modify. The most important
+trap for us is for @code{ta 1}. Without that, we can't single step or
+do breakpoints. Everything else is unnecessary for the proper operation
+of the debugger/stub.
+
+From reading the stub, it's probably not obvious how breakpoints work.
+They are simply done by deposit/examine operations from @value{GDBN}.
+
+@section ROM Monitor Interface
+
+@section Custom Protocols
+
+@section Transport Layer
+
+@section Builtin Simulator
+
+
+@node Native Debugging
+
+@chapter Native Debugging
+@cindex native debugging
+
+Several files control @value{GDBN}'s configuration for native support:
+
+@table @file
+@vindex NATDEPFILES
+@item gdb/config/@var{arch}/@var{xyz}.mh
+Specifies Makefile fragments needed when hosting @emph{or native} on
+machine @var{xyz}. In particular, this lists the required
+native-dependent object files, by defining @samp{NATDEPFILES=@dots{}}.
+Also specifies the header file which describes native support on
+@var{xyz}, by defining @samp{NAT_FILE= nm-@var{xyz}.h}. You can also
+define @samp{NAT_CFLAGS}, @samp{NAT_ADD_FILES}, @samp{NAT_CLIBS},
+@samp{NAT_CDEPS}, etc.; see @file{Makefile.in}.
+
+@item gdb/config/@var{arch}/nm-@var{xyz}.h
+(@file{nm.h} is a link to this file, created by @code{configure}). Contains C
+macro definitions describing the native system environment, such as
+child process control and core file support.
+
+@item gdb/@var{xyz}-nat.c
+Contains any miscellaneous C code required for this native support of
+this machine. On some machines it doesn't exist at all.
+@end table
+
+There are some ``generic'' versions of routines that can be used by
+various systems. These can be customized in various ways by macros
+defined in your @file{nm-@var{xyz}.h} file. If these routines work for
+the @var{xyz} host, you can just include the generic file's name (with
+@samp{.o}, not @samp{.c}) in @code{NATDEPFILES}.
+
+Otherwise, if your machine needs custom support routines, you will need
+to write routines that perform the same functions as the generic file.
+Put them into @file{@var{xyz}-nat.c}, and put @file{@var{xyz}-nat.o}
+into @code{NATDEPFILES}.
+
+@table @file
+@item inftarg.c
+This contains the @emph{target_ops vector} that supports Unix child
+processes on systems which use ptrace and wait to control the child.
+
+@item procfs.c
+This contains the @emph{target_ops vector} that supports Unix child
+processes on systems which use /proc to control the child.
+
+@item fork-child.c
+This does the low-level grunge that uses Unix system calls to do a ``fork
+and exec'' to start up a child process.
+
+@item infptrace.c
+This is the low level interface to inferior processes for systems using
+the Unix @code{ptrace} call in a vanilla way.
+@end table
+
+@section Native core file Support
+@cindex native core files
+
+@table @file
+@findex fetch_core_registers
+@item core-aout.c::fetch_core_registers()
+Support for reading registers out of a core file. This routine calls
+@code{register_addr()}, see below. Now that BFD is used to read core
+files, virtually all machines should use @code{core-aout.c}, and should
+just provide @code{fetch_core_registers} in @code{@var{xyz}-nat.c} (or
+@code{REGISTER_U_ADDR} in @code{nm-@var{xyz}.h}).
+
+@item core-aout.c::register_addr()
+If your @code{nm-@var{xyz}.h} file defines the macro
+@code{REGISTER_U_ADDR(addr, blockend, regno)}, it should be defined to
+set @code{addr} to the offset within the @samp{user} struct of @value{GDBN}
+register number @code{regno}. @code{blockend} is the offset within the
+``upage'' of @code{u.u_ar0}. If @code{REGISTER_U_ADDR} is defined,
+@file{core-aout.c} will define the @code{register_addr()} function and
+use the macro in it. If you do not define @code{REGISTER_U_ADDR}, but
+you are using the standard @code{fetch_core_registers()}, you will need
+to define your own version of @code{register_addr()}, put it into your
+@code{@var{xyz}-nat.c} file, and be sure @code{@var{xyz}-nat.o} is in
+the @code{NATDEPFILES} list. If you have your own
+@code{fetch_core_registers()}, you may not need a separate
+@code{register_addr()}. Many custom @code{fetch_core_registers()}
+implementations simply locate the registers themselves.@refill
@end table
-@node Native Conditionals
-@chapter Native Conditionals
+When making @value{GDBN} run native on a new operating system, to make it
+possible to debug core files, you will need to either write specific
+code for parsing your OS's core files, or customize
+@file{bfd/trad-core.c}. First, use whatever @code{#include} files your
+machine uses to define the struct of registers that is accessible
+(possibly in the u-area) in a core file (rather than
+@file{machine/reg.h}), and an include file that defines whatever header
+exists on a core file (e.g. the u-area or a @code{struct core}). Then
+modify @code{trad_unix_core_file_p} to use these values to set up the
+section information for the data segment, stack segment, any other
+segments in the core file (perhaps shared library contents or control
+information), ``registers'' segment, and if there are two discontiguous
+sets of registers (e.g. integer and float), the ``reg2'' segment. This
+section information basically delimits areas in the core file in a
+standard way, which the section-reading routines in BFD know how to seek
+around in.
+
+Then back in @value{GDBN}, you need a matching routine called
+@code{fetch_core_registers}. If you can use the generic one, it's in
+@file{core-aout.c}; if not, it's in your @file{@var{xyz}-nat.c} file.
+It will be passed a char pointer to the entire ``registers'' segment,
+its length, and a zero; or a char pointer to the entire ``regs2''
+segment, its length, and a 2. The routine should suck out the supplied
+register values and install them into @value{GDBN}'s ``registers'' array.
+
+If your system uses @file{/proc} to control processes, and uses ELF
+format core files, then you may be able to use the same routines for
+reading the registers out of processes and out of core files.
+
+@section ptrace
+
+@section /proc
-When GDB is configured and compiled, various macros are defined or left
-undefined, to control compilation when the host and target systems
-are the same. These macros should be defined (or left undefined)
-in @file{nm-@var{system}.h}.
+@section win32
+
+@section shared libraries
+
+@section Native Conditionals
+@cindex native conditionals
+
+When @value{GDBN} is configured and compiled, various macros are
+defined or left undefined, to control compilation when the host and
+target systems are the same. These macros should be defined (or left
+undefined) in @file{nm-@var{system}.h}.
@table @code
@item ATTACH_DETACH
-If defined, then gdb will include support for the @code{attach} and
+@findex ATTACH_DETACH
+If defined, then @value{GDBN} will include support for the @code{attach} and
@code{detach} commands.
+
+@item CHILD_PREPARE_TO_STORE
+@findex CHILD_PREPARE_TO_STORE
+If the machine stores all registers at once in the child process, then
+define this to ensure that all values are correct. This usually entails
+a read from the child.
+
+[Note that this is incorrectly defined in @file{xm-@var{system}.h} files
+currently.]
+
@item FETCH_INFERIOR_REGISTERS
-Define this if the native-dependent code will provide its
-own routines
+@findex FETCH_INFERIOR_REGISTERS
+Define this if the native-dependent code will provide its own routines
@code{fetch_inferior_registers} and @code{store_inferior_registers} in
-@file{@var{HOST}-nat.c}.
-If this symbol is @emph{not} defined, and @file{infptrace.c}
-is included in this configuration, the default routines in
-@file{infptrace.c} are used for these functions.
+@file{@var{host}-nat.c}. If this symbol is @emph{not} defined, and
+@file{infptrace.c} is included in this configuration, the default
+routines in @file{infptrace.c} are used for these functions.
+
+@item FILES_INFO_HOOK
+@findex FILES_INFO_HOOK
+(Only defined for Convex.)
+
+@item FP0_REGNUM
+@findex FP0_REGNUM
+This macro is normally defined to be the number of the first floating
+point register, if the machine has such registers. As such, it would
+appear only in target-specific code. However, @file{/proc} support uses this
+to decide whether floats are in use on this target.
+
@item GET_LONGJMP_TARGET
-For most machines, this is a target-dependent parameter. On the DECstation
-and the Iris, this is a native-dependent parameter, since <setjmp.h> is
-needed to define it.
-
-This macro determines the target PC address that longjmp() will jump
-to, assuming that we have just stopped at a longjmp breakpoint. It
-takes a CORE_ADDR * as argument, and stores the target PC value through
-this pointer. It examines the current state of the machine as needed.
+@findex GET_LONGJMP_TARGET
+For most machines, this is a target-dependent parameter. On the
+DECstation and the Iris, this is a native-dependent parameter, since
+@file{setjmp.h} is needed to define it.
+
+This macro determines the target PC address that @code{longjmp} will jump to,
+assuming that we have just stopped at a longjmp breakpoint. It takes a
+@code{CORE_ADDR *} as argument, and stores the target PC value through this
+pointer. It examines the current state of the machine as needed.
+
+@item I386_USE_GENERIC_WATCHPOINTS
+An x86-based machine can define this to use the generic x86 watchpoint
+support; see @ref{Algorithms, I386_USE_GENERIC_WATCHPOINTS}.
+
+@item KERNEL_U_ADDR
+@findex KERNEL_U_ADDR
+Define this to the address of the @code{u} structure (the ``user
+struct'', also known as the ``u-page'') in kernel virtual memory. @value{GDBN}
+needs to know this so that it can subtract this address from absolute
+addresses in the upage, that are obtained via ptrace or from core files.
+On systems that don't need this value, set it to zero.
+
+@item KERNEL_U_ADDR_BSD
+@findex KERNEL_U_ADDR_BSD
+Define this to cause @value{GDBN} to determine the address of @code{u} at
+runtime, by using Berkeley-style @code{nlist} on the kernel's image in
+the root directory.
+
+@item KERNEL_U_ADDR_HPUX
+@findex KERNEL_U_ADDR_HPUX
+Define this to cause @value{GDBN} to determine the address of @code{u} at
+runtime, by using HP-style @code{nlist} on the kernel's image in the
+root directory.
+
+@item ONE_PROCESS_WRITETEXT
+@findex ONE_PROCESS_WRITETEXT
+Define this to be able to, when a breakpoint insertion fails, warn the
+user that another process may be running with the same executable.
+
+@item PREPARE_TO_PROCEED (@var{select_it})
+@findex PREPARE_TO_PROCEED
+This (ugly) macro allows a native configuration to customize the way the
+@code{proceed} function in @file{infrun.c} deals with switching between
+threads.
+
+In a multi-threaded task we may select another thread and then continue
+or step. But if the old thread was stopped at a breakpoint, it will
+immediately cause another breakpoint stop without any execution (i.e. it
+will report a breakpoint hit incorrectly). So @value{GDBN} must step over it
+first.
+
+If defined, @code{PREPARE_TO_PROCEED} should check the current thread
+against the thread that reported the most recent event. If a step-over
+is required, it returns TRUE. If @var{select_it} is non-zero, it should
+reselect the old thread.
+
@item PROC_NAME_FMT
+@findex PROC_NAME_FMT
Defines the format for the name of a @file{/proc} device. Should be
defined in @file{nm.h} @emph{only} in order to override the default
definition in @file{procfs.c}.
+
@item PTRACE_FP_BUG
-mach386-xdep.c
+@findex PTRACE_FP_BUG
+See @file{mach386-xdep.c}.
+
@item PTRACE_ARG3_TYPE
-The type of the third argument to the @code{ptrace} system call, if it exists
-and is different from @code{int}.
+@findex PTRACE_ARG3_TYPE
+The type of the third argument to the @code{ptrace} system call, if it
+exists and is different from @code{int}.
+
@item REGISTER_U_ADDR
-Defines the offset of the registers in the ``u area''; @pxref{Host}.
-@item USE_PROC_FS
-This determines whether small routines in @file{*-tdep.c}, which
-translate register values
-between GDB's internal representation and the /proc representation,
-are compiled.
-@item U_REGS_OFFSET
-This is the offset of the registers in the upage. It need only be
-defined if the generic ptrace register access routines in
-@file{infptrace.c} are being used (that is,
-@file{infptrace.c} is configured in, and
-@code{FETCH_INFERIOR_REGISTERS} is not defined). If the default value
-from @file{infptrace.c} is good enough, leave it undefined.
-
-The default value means that u.u_ar0 @emph{points to} the location of the
-registers. I'm guessing that @code{#define U_REGS_OFFSET 0} means that
-u.u_ar0 @emph{is} the location of the registers.
-@end table
+@findex REGISTER_U_ADDR
+Defines the offset of the registers in the ``u area''.
-@node Obsolete Conditionals
-@chapter Obsolete Conditionals
+@item SHELL_COMMAND_CONCAT
+@findex SHELL_COMMAND_CONCAT
+If defined, is a string to prefix on the shell command used to start the
+inferior.
+
+@item SHELL_FILE
+@findex SHELL_FILE
+If defined, this is the name of the shell to use to run the inferior.
+Defaults to @code{"/bin/sh"}.
+
+@item SOLIB_ADD (@var{filename}, @var{from_tty}, @var{targ}, @var{readsyms})
+@findex SOLIB_ADD
+Define this to expand into an expression that will cause the symbols in
+@var{filename} to be added to @value{GDBN}'s symbol table. If
+@var{readsyms} is zero symbols are not read but any necessary low level
+processing for @var{filename} is still done.
+
+@item SOLIB_CREATE_INFERIOR_HOOK
+@findex SOLIB_CREATE_INFERIOR_HOOK
+Define this to expand into any shared-library-relocation code that you
+want to be run just after the child process has been forked.
+
+@item START_INFERIOR_TRAPS_EXPECTED
+@findex START_INFERIOR_TRAPS_EXPECTED
+When starting an inferior, @value{GDBN} normally expects to trap
+twice; once when
+the shell execs, and once when the program itself execs. If the actual
+number of traps is something other than 2, then define this macro to
+expand into the number expected.
+
+@item SVR4_SHARED_LIBS
+@findex SVR4_SHARED_LIBS
+Define this to indicate that SVR4-style shared libraries are in use.
+
+@item USE_PROC_FS
+@findex USE_PROC_FS
+This determines whether small routines in @file{*-tdep.c}, which
+translate register values between @value{GDBN}'s internal
+representation and the @file{/proc} representation, are compiled.
+
+@item U_REGS_OFFSET
+@findex U_REGS_OFFSET
+This is the offset of the registers in the upage. It need only be
+defined if the generic ptrace register access routines in
+@file{infptrace.c} are being used (that is, @file{infptrace.c} is
+configured in, and @code{FETCH_INFERIOR_REGISTERS} is not defined). If
+the default value from @file{infptrace.c} is good enough, leave it
+undefined.
+
+The default value means that u.u_ar0 @emph{points to} the location of
+the registers. I'm guessing that @code{#define U_REGS_OFFSET 0} means
+that @code{u.u_ar0} @emph{is} the location of the registers.
+
+@item CLEAR_SOLIB
+@findex CLEAR_SOLIB
+See @file{objfiles.c}.
+
+@item DEBUG_PTRACE
+@findex DEBUG_PTRACE
+Define this to debug @code{ptrace} calls.
+@end table
+
+
+@node Support Libraries
+
+@chapter Support Libraries
+
+@section BFD
+@cindex BFD library
+
+BFD provides support for @value{GDBN} in several ways:
+
+@table @emph
+@item identifying executable and core files
+BFD will identify a variety of file types, including a.out, coff, and
+several variants thereof, as well as several kinds of core files.
+
+@item access to sections of files
+BFD parses the file headers to determine the names, virtual addresses,
+sizes, and file locations of all the various named sections in files
+(such as the text section or the data section). @value{GDBN} simply
+calls BFD to read or write section @var{x} at byte offset @var{y} for
+length @var{z}.
+
+@item specialized core file support
+BFD provides routines to determine the failing command name stored in a
+core file, the signal with which the program failed, and whether a core
+file matches (i.e.@: could be a core dump of) a particular executable
+file.
+
+@item locating the symbol information
+@value{GDBN} uses an internal interface of BFD to determine where to find the
+symbol information in an executable file or symbol-file. @value{GDBN} itself
+handles the reading of symbols, since BFD does not ``understand'' debug
+symbols, but @value{GDBN} uses BFD's cached information to find the symbols,
+string table, etc.
+@end table
+
+@section opcodes
+@cindex opcodes library
+
+The opcodes library provides @value{GDBN}'s disassembler. (It's a separate
+library because it's also used in binutils, for @file{objdump}).
+
+@section readline
+
+@section mmalloc
+
+@section libiberty
+
+@section gnu-regex
+@cindex regular expressions library
+
+Regex conditionals.
+
+@table @code
+@item C_ALLOCA
+
+@item NFAILURES
+
+@item RE_NREGS
+
+@item SIGN_EXTEND_CHAR
+
+@item SWITCH_ENUM_BUG
+
+@item SYNTAX_TABLE
+
+@item Sword
+
+@item sparc
+@end table
+
+@section include
+
+@node Coding
+
+@chapter Coding
+
+This chapter covers topics that are lower-level than the major
+algorithms of @value{GDBN}.
+
+@section Cleanups
+@cindex cleanups
+
+Cleanups are a structured way to deal with things that need to be done
+later. When your code does something (like @code{malloc} some memory,
+or open a file) that needs to be undone later (e.g., free the memory or
+close the file), it can make a cleanup. The cleanup will be done at
+some future point: when the command is finished, when an error occurs,
+or when your code decides it's time to do cleanups.
+
+You can also discard cleanups, that is, throw them away without doing
+what they say. This is only done if you ask that it be done.
+
+Syntax:
+
+@table @code
+@item struct cleanup *@var{old_chain};
+Declare a variable which will hold a cleanup chain handle.
+
+@findex make_cleanup
+@item @var{old_chain} = make_cleanup (@var{function}, @var{arg});
+Make a cleanup which will cause @var{function} to be called with
+@var{arg} (a @code{char *}) later. The result, @var{old_chain}, is a
+handle that can be passed to @code{do_cleanups} or
+@code{discard_cleanups} later. Unless you are going to call
+@code{do_cleanups} or @code{discard_cleanups} yourself, you can ignore
+the result from @code{make_cleanup}.
+
+@findex do_cleanups
+@item do_cleanups (@var{old_chain});
+Perform all cleanups done since @code{make_cleanup} returned
+@var{old_chain}. E.g.:
+
+@example
+make_cleanup (a, 0);
+old = make_cleanup (b, 0);
+do_cleanups (old);
+@end example
+
+@noindent
+will call @code{b()} but will not call @code{a()}. The cleanup that
+calls @code{a()} will remain in the cleanup chain, and will be done
+later unless otherwise discarded.@refill
+
+@findex discard_cleanups
+@item discard_cleanups (@var{old_chain});
+Same as @code{do_cleanups} except that it just removes the cleanups from
+the chain and does not call the specified functions.
+@end table
+
+Some functions, e.g. @code{fputs_filtered()} or @code{error()}, specify
+that they ``should not be called when cleanups are not in place''. This
+means that any actions you need to reverse in the case of an error or
+interruption must be on the cleanup chain before you call these
+functions, since they might never return to your code (they
+@samp{longjmp} instead).
+
+@section Wrapping Output Lines
+@cindex line wrap in output
+
+@findex wrap_here
+Output that goes through @code{printf_filtered} or @code{fputs_filtered}
+or @code{fputs_demangled} needs only to have calls to @code{wrap_here}
+added in places that would be good breaking points. The utility
+routines will take care of actually wrapping if the line width is
+exceeded.
+
+The argument to @code{wrap_here} is an indentation string which is
+printed @emph{only} if the line breaks there. This argument is saved
+away and used later. It must remain valid until the next call to
+@code{wrap_here} or until a newline has been printed through the
+@code{*_filtered} functions. Don't pass in a local variable and then
+return!
+
+It is usually best to call @code{wrap_here} after printing a comma or
+space. If you call it before printing a space, make sure that your
+indentation properly accounts for the leading space that will print if
+the line wraps there.
+
+Any function or set of functions that produce filtered output must
+finish by printing a newline, to flush the wrap buffer, before switching
+to unfiltered (@code{printf}) output. Symbol reading routines that
+print warnings are a good example.
+
+@section @value{GDBN} Coding Standards
+@cindex coding standards
+
+@value{GDBN} follows the GNU coding standards, as described in
+@file{etc/standards.texi}. This file is also available for anonymous
+FTP from GNU archive sites. @value{GDBN} takes a strict interpretation
+of the standard; in general, when the GNU standard recommends a practice
+but does not require it, @value{GDBN} requires it.
+
+@value{GDBN} follows an additional set of coding standards specific to
+@value{GDBN}, as described in the following sections.
+
+
+@subsection ISO-C
+
+@value{GDBN} assumes an ISO-C compliant compiler.
+
+@value{GDBN} does not assume an ISO-C or POSIX compliant C library.
+
+
+@subsection Memory Management
+
+@value{GDBN} does not use the functions @code{malloc}, @code{realloc},
+@code{calloc}, @code{free} and @code{asprintf}.
+
+@value{GDBN} uses the functions @code{xmalloc}, @code{xrealloc} and
+@code{xcalloc} when allocating memory. Unlike @code{malloc} et.al.@:
+these functions do not return when the memory pool is empty. Instead,
+they unwind the stack using cleanups. These functions return
+@code{NULL} when requested to allocate a chunk of memory of size zero.
+
+@emph{Pragmatics: By using these functions, the need to check every
+memory allocation is removed. These functions provide portable
+behavior.}
+
+@value{GDBN} does not use the function @code{free}.
+
+@value{GDBN} uses the function @code{xfree} to return memory to the
+memory pool. Consistent with ISO-C, this function ignores a request to
+free a @code{NULL} pointer.
+
+@emph{Pragmatics: On some systems @code{free} fails when passed a
+@code{NULL} pointer.}
+
+@value{GDBN} can use the non-portable function @code{alloca} for the
+allocation of small temporary values (such as strings).
+
+@emph{Pragmatics: This function is very non-portable. Some systems
+restrict the memory being allocated to no more than a few kilobytes.}
+
+@value{GDBN} uses the string function @code{xstrdup} and the print
+function @code{xasprintf}.
+
+@emph{Pragmatics: @code{asprintf} and @code{strdup} can fail. Print
+functions such as @code{sprintf} are very prone to buffer overflow
+errors.}
+
+
+@subsection Compiler Warnings
+@cindex compiler warnings
+
+With few exceptions, developers should include the configuration option
+@samp{--enable-gdb-build-warnings=,-Werror} when building @value{GDBN}.
+The exceptions are listed in the file @file{gdb/MAINTAINERS}.
+
+This option causes @value{GDBN} (when built using GCC) to be compiled
+with a carefully selected list of compiler warning flags. Any warnings
+from those flags being treated as errors.
+
+The current list of warning flags includes:
+
+@table @samp
+@item -Wimplicit
+Since @value{GDBN} coding standard requires all functions to be declared
+using a prototype, the flag has the side effect of ensuring that
+prototyped functions are always visible with out resorting to
+@samp{-Wstrict-prototypes}.
+
+@item -Wreturn-type
+Such code often appears to work except on instruction set architectures
+that use register windows.
+
+@item -Wcomment
+
+@item -Wtrigraphs
+
+@item -Wformat
+Since @value{GDBN} uses the @code{format printf} attribute on all
+@code{printf} like functions this checks not just @code{printf} calls
+but also calls to functions such as @code{fprintf_unfiltered}.
+
+@item -Wparentheses
+This warning includes uses of the assignment operator within an
+@code{if} statement.
+
+@item -Wpointer-arith
+
+@item -Wuninitialized
+@end table
+
+@emph{Pragmatics: Due to the way that @value{GDBN} is implemented most
+functions have unused parameters. Consequently the warning
+@samp{-Wunused-parameter} is precluded from the list. The macro
+@code{ATTRIBUTE_UNUSED} is not used as it leads to false negatives ---
+it is not an error to have @code{ATTRIBUTE_UNUSED} on a parameter that
+is being used. The options @samp{-Wall} and @samp{-Wunused} are also
+precluded because they both include @samp{-Wunused-parameter}.}
+
+@emph{Pragmatics: @value{GDBN} has not simply accepted the warnings
+enabled by @samp{-Wall -Werror -W...}. Instead it is selecting warnings
+when and where their benefits can be demonstrated.}
+
+@subsection Formatting
+
+@cindex source code formatting
+The standard GNU recommendations for formatting must be followed
+strictly.
+
+A function declaration should not have its name in column zero. A
+function definition should have its name in column zero.
+
+@example
+/* Declaration */
+static void foo (void);
+/* Definition */
+void
+foo (void)
+@{
+@}
+@end example
+
+@emph{Pragmatics: This simplifies scripting. Function definitions can
+be found using @samp{^function-name}.}
+
+There must be a space between a function or macro name and the opening
+parenthesis of its argument list (except for macro definitions, as
+required by C). There must not be a space after an open paren/bracket
+or before a close paren/bracket.
+
+While additional whitespace is generally helpful for reading, do not use
+more than one blank line to separate blocks, and avoid adding whitespace
+after the end of a program line (as of 1/99, some 600 lines had
+whitespace after the semicolon). Excess whitespace causes difficulties
+for @code{diff} and @code{patch} utilities.
+
+Pointers are declared using the traditional K&R C style:
+
+@example
+void *foo;
+@end example
+
+@noindent
+and not:
+
+@example
+void * foo;
+void* foo;
+@end example
+
+@subsection Comments
+
+@cindex comment formatting
+The standard GNU requirements on comments must be followed strictly.
+
+Block comments must appear in the following form, with no @code{/*}- or
+@code{*/}-only lines, and no leading @code{*}:
+
+@example
+/* Wait for control to return from inferior to debugger. If inferior
+ gets a signal, we may decide to start it up again instead of
+ returning. That is why there is a loop in this function. When
+ this function actually returns it means the inferior should be left
+ stopped and @value{GDBN} should read more commands. */
+@end example
+
+(Note that this format is encouraged by Emacs; tabbing for a multi-line
+comment works correctly, and @kbd{M-q} fills the block consistently.)
+
+Put a blank line between the block comments preceding function or
+variable definitions, and the definition itself.
+
+In general, put function-body comments on lines by themselves, rather
+than trying to fit them into the 20 characters left at the end of a
+line, since either the comment or the code will inevitably get longer
+than will fit, and then somebody will have to move it anyhow.
+
+@subsection C Usage
+
+@cindex C data types
+Code must not depend on the sizes of C data types, the format of the
+host's floating point numbers, the alignment of anything, or the order
+of evaluation of expressions.
+
+@cindex function usage
+Use functions freely. There are only a handful of compute-bound areas
+in @value{GDBN} that might be affected by the overhead of a function
+call, mainly in symbol reading. Most of @value{GDBN}'s performance is
+limited by the target interface (whether serial line or system call).
+
+However, use functions with moderation. A thousand one-line functions
+are just as hard to understand as a single thousand-line function.
+
+@emph{Macros are bad, M'kay.}
+(But if you have to use a macro, make sure that the macro arguments are
+protected with parentheses.)
+
+@cindex types
+
+Declarations like @samp{struct foo *} should be used in preference to
+declarations like @samp{typedef struct foo @{ @dots{} @} *foo_ptr}.
+
+
+@subsection Function Prototypes
+@cindex function prototypes
+
+Prototypes must be used when both @emph{declaring} and @emph{defining}
+a function. Prototypes for @value{GDBN} functions must include both the
+argument type and name, with the name matching that used in the actual
+function definition.
+
+All external functions should have a declaration in a header file that
+callers include, except for @code{_initialize_*} functions, which must
+be external so that @file{init.c} construction works, but shouldn't be
+visible to random source files.
+
+Where a source file needs a forward declaration of a static function,
+that declaration must appear in a block near the top of the source file.
+
+
+@subsection Internal Error Recovery
+
+During its execution, @value{GDBN} can encounter two types of errors.
+User errors and internal errors. User errors include not only a user
+entering an incorrect command but also problems arising from corrupt
+object files and system errors when interacting with the target.
+Internal errors include situtations where @value{GDBN} has detected, at
+run time, a corrupt or erroneous situtation.
+
+When reporting an internal error, @value{GDBN} uses
+@code{internal_error} and @code{gdb_assert}.
+
+@value{GDBN} must not call @code{abort} or @code{assert}.
+
+@emph{Pragmatics: There is no @code{internal_warning} function. Either
+the code detected a user error, recovered from it and issued a
+@code{warning} or the code failed to correctly recover from the user
+error and issued an @code{internal_error}.}
+
+@subsection File Names
+
+Any file used when building the core of @value{GDBN} must be in lower
+case. Any file used when building the core of @value{GDBN} must be 8.3
+unique. These requirements apply to both source and generated files.
+
+@emph{Pragmatics: The core of @value{GDBN} must be buildable on many
+platforms including DJGPP and MacOS/HFS. Every time an unfriendly file
+is introduced to the build process both @file{Makefile.in} and
+@file{configure.in} need to be modified accordingly. Compare the
+convoluted conversion process needed to transform @file{COPYING} into
+@file{copying.c} with the conversion needed to transform
+@file{version.in} into @file{version.c}.}
+
+Any file non 8.3 compliant file (that is not used when building the core
+of @value{GDBN}) must be added to @file{gdb/config/djgpp/fnchange.lst}.
+
+@emph{Pragmatics: This is clearly a compromise.}
+
+When @value{GDBN} has a local version of a system header file (ex
+@file{string.h}) the file name based on the POSIX header prefixed with
+@file{gdb_} (@file{gdb_string.h}).
+
+For other files @samp{-} is used as the separator.
+
+
+@subsection Include Files
+
+All @file{.c} files should include @file{defs.h} first.
+
+All @file{.c} files should explicitly include the headers for any
+declarations they refer to. They should not rely on files being
+included indirectly.
+
+With the exception of the global definitions supplied by @file{defs.h},
+a header file should explictily include the header declaring any
+@code{typedefs} et.al.@: it refers to.
+
+@code{extern} declarations should never appear in @code{.c} files.
+
+All include files should be wrapped in:
+
+@example
+#ifndef INCLUDE_FILE_NAME_H
+#define INCLUDE_FILE_NAME_H
+header body
+#endif
+@end example
+
+
+@subsection Clean Design and Portable Implementation
+
+@cindex design
+In addition to getting the syntax right, there's the little question of
+semantics. Some things are done in certain ways in @value{GDBN} because long
+experience has shown that the more obvious ways caused various kinds of
+trouble.
+
+@cindex assumptions about targets
+You can't assume the byte order of anything that comes from a target
+(including @var{value}s, object files, and instructions). Such things
+must be byte-swapped using @code{SWAP_TARGET_AND_HOST} in
+@value{GDBN}, or one of the swap routines defined in @file{bfd.h},
+such as @code{bfd_get_32}.
+
+You can't assume that you know what interface is being used to talk to
+the target system. All references to the target must go through the
+current @code{target_ops} vector.
+
+You can't assume that the host and target machines are the same machine
+(except in the ``native'' support modules). In particular, you can't
+assume that the target machine's header files will be available on the
+host machine. Target code must bring along its own header files --
+written from scratch or explicitly donated by their owner, to avoid
+copyright problems.
+
+@cindex portability
+Insertion of new @code{#ifdef}'s will be frowned upon. It's much better
+to write the code portably than to conditionalize it for various
+systems.
+
+@cindex system dependencies
+New @code{#ifdef}'s which test for specific compilers or manufacturers
+or operating systems are unacceptable. All @code{#ifdef}'s should test
+for features. The information about which configurations contain which
+features should be segregated into the configuration files. Experience
+has proven far too often that a feature unique to one particular system
+often creeps into other systems; and that a conditional based on some
+predefined macro for your current system will become worthless over
+time, as new versions of your system come out that behave differently
+with regard to this feature.
-Fragments of old code in GDB sometimes reference or set the following
-configuration macros. They should not be used by new code, and
-old uses should be removed as those parts of the debugger are
-otherwise touched.
+Adding code that handles specific architectures, operating systems,
+target interfaces, or hosts, is not acceptable in generic code.
+
+@cindex portable file name handling
+@cindex file names, portability
+One particularly notorious area where system dependencies tend to
+creep in is handling of file names. The mainline @value{GDBN} code
+assumes Posix semantics of file names: absolute file names begin with
+a forward slash @file{/}, slashes are used to separate leading
+directories, case-sensitive file names. These assumptions are not
+necessarily true on non-Posix systems such as MS-Windows. To avoid
+system-dependent code where you need to take apart or construct a file
+name, use the following portable macros:
+
+@table @code
+@findex HAVE_DOS_BASED_FILE_SYSTEM
+@item HAVE_DOS_BASED_FILE_SYSTEM
+This preprocessing symbol is defined to a non-zero value on hosts
+whose filesystems belong to the MS-DOS/MS-Windows family. Use this
+symbol to write conditional code which should only be compiled for
+such hosts.
+
+@findex IS_DIR_SEPARATOR
+@item IS_DIR_SEPARATOR (@var{c}
+Evaluates to a non-zero value if @var{c} is a directory separator
+character. On Unix and GNU/Linux systems, only a slash @file{/} is
+such a character, but on Windows, both @file{/} and @file{\} will
+pass.
+
+@findex IS_ABSOLUTE_PATH
+@item IS_ABSOLUTE_PATH (@var{file})
+Evaluates to a non-zero value if @var{file} is an absolute file name.
+For Unix and GNU/Linux hosts, a name which begins with a slash
+@file{/} is absolute. On DOS and Windows, @file{d:/foo} and
+@file{x:\bar} are also absolute file names.
+
+@findex FILENAME_CMP
+@item FILENAME_CMP (@var{f1}, @var{f2})
+Calls a function which compares file names @var{f1} and @var{f2} as
+appropriate for the underlying host filesystem. For Posix systems,
+this simply calls @code{strcmp}; on case-insensitive filesystems it
+will call @code{strcasecmp} instead.
+
+@findex DIRNAME_SEPARATOR
+@item DIRNAME_SEPARATOR
+Evaluates to a character which separates directories in
+@code{PATH}-style lists, typically held in environment variables.
+This character is @samp{:} on Unix, @samp{;} on DOS and Windows.
+
+@findex SLASH_STRING
+@item SLASH_STRING
+This evaluates to a constant string you should use to produce an
+absolute filename from leading directories and the file's basename.
+@code{SLASH_STRING} is @code{"/"} on most systems, but might be
+@code{"\\"} for some Windows-based ports.
+@end table
+
+In addition to using these macros, be sure to use portable library
+functions whenever possible. For example, to extract a directory or a
+basename part from a file name, use the @code{dirname} and
+@code{basename} library functions (available in @code{libiberty} for
+platforms which don't provide them), instead of searching for a slash
+with @code{strrchr}.
+
+Another way to generalize @value{GDBN} along a particular interface is with an
+attribute struct. For example, @value{GDBN} has been generalized to handle
+multiple kinds of remote interfaces---not by @code{#ifdef}s everywhere, but
+by defining the @code{target_ops} structure and having a current target (as
+well as a stack of targets below it, for memory references). Whenever
+something needs to be done that depends on which remote interface we are
+using, a flag in the current target_ops structure is tested (e.g.,
+@code{target_has_stack}), or a function is called through a pointer in the
+current target_ops structure. In this way, when a new remote interface
+is added, only one module needs to be touched---the one that actually
+implements the new remote interface. Other examples of
+attribute-structs are BFD access to multiple kinds of object file
+formats, or @value{GDBN}'s access to multiple source languages.
+
+Please avoid duplicating code. For example, in @value{GDBN} 3.x all
+the code interfacing between @code{ptrace} and the rest of
+@value{GDBN} was duplicated in @file{*-dep.c}, and so changing
+something was very painful. In @value{GDBN} 4.x, these have all been
+consolidated into @file{infptrace.c}. @file{infptrace.c} can deal
+with variations between systems the same way any system-independent
+file would (hooks, @code{#if defined}, etc.), and machines which are
+radically different don't need to use @file{infptrace.c} at all.
+
+All debugging code must be controllable using the @samp{set debug
+@var{module}} command. Do not use @code{printf} to print trace
+messages. Use @code{fprintf_unfiltered(gdb_stdlog, ...}. Do not use
+@code{#ifdef DEBUG}.
+
+
+@node Porting GDB
+
+@chapter Porting @value{GDBN}
+@cindex porting to new machines
+
+Most of the work in making @value{GDBN} compile on a new machine is in
+specifying the configuration of the machine. This is done in a
+dizzying variety of header files and configuration scripts, which we
+hope to make more sensible soon. Let's say your new host is called an
+@var{xyz} (e.g., @samp{sun4}), and its full three-part configuration
+name is @code{@var{arch}-@var{xvend}-@var{xos}} (e.g.,
+@samp{sparc-sun-sunos4}). In particular:
+
+@itemize @bullet
+@item
+In the top level directory, edit @file{config.sub} and add @var{arch},
+@var{xvend}, and @var{xos} to the lists of supported architectures,
+vendors, and operating systems near the bottom of the file. Also, add
+@var{xyz} as an alias that maps to
+@code{@var{arch}-@var{xvend}-@var{xos}}. You can test your changes by
+running
+
+@example
+./config.sub @var{xyz}
+@end example
+
+@noindent
+and
+
+@example
+./config.sub @code{@var{arch}-@var{xvend}-@var{xos}}
+@end example
+
+@noindent
+which should both respond with @code{@var{arch}-@var{xvend}-@var{xos}}
+and no error messages.
+
+@noindent
+You need to port BFD, if that hasn't been done already. Porting BFD is
+beyond the scope of this manual.
+
+@item
+To configure @value{GDBN} itself, edit @file{gdb/configure.host} to recognize
+your system and set @code{gdb_host} to @var{xyz}, and (unless your
+desired target is already available) also edit @file{gdb/configure.tgt},
+setting @code{gdb_target} to something appropriate (for instance,
+@var{xyz}).
+
+@item
+Finally, you'll need to specify and define @value{GDBN}'s host-, native-, and
+target-dependent @file{.h} and @file{.c} files used for your
+configuration.
+@end itemize
+
+@section Configuring @value{GDBN} for Release
+
+@cindex preparing a release
+@cindex making a distribution tarball
+From the top level directory (containing @file{gdb}, @file{bfd},
+@file{libiberty}, and so on):
+
+@example
+make -f Makefile.in gdb.tar.gz
+@end example
+
+@noindent
+This will properly configure, clean, rebuild any files that are
+distributed pre-built (e.g. @file{c-exp.tab.c} or @file{refcard.ps}),
+and will then make a tarfile. (If the top level directory has already
+been configured, you can just do @code{make gdb.tar.gz} instead.)
+
+This procedure requires:
+
+@itemize @bullet
+
+@item
+symbolic links;
+
+@item
+@code{makeinfo} (texinfo2 level);
+
+@item
+@TeX{};
+
+@item
+@code{dvips};
+
+@item
+@code{yacc} or @code{bison}.
+@end itemize
+
+@noindent
+@dots{} and the usual slew of utilities (@code{sed}, @code{tar}, etc.).
+
+@subheading TEMPORARY RELEASE PROCEDURE FOR DOCUMENTATION
+
+@file{gdb.texinfo} is currently marked up using the texinfo-2 macros,
+which are not yet a default for anything (but we have to start using
+them sometime).
+
+For making paper, the only thing this implies is the right generation of
+@file{texinfo.tex} needs to be included in the distribution.
+
+For making info files, however, rather than duplicating the texinfo2
+distribution, generate @file{gdb-all.texinfo} locally, and include the
+files @file{gdb.info*} in the distribution. Note the plural;
+@code{makeinfo} will split the document into one overall file and five
+or so included files.
+
+@node Testsuite
+
+@chapter Testsuite
+@cindex test suite
+
+The testsuite is an important component of the @value{GDBN} package.
+While it is always worthwhile to encourage user testing, in practice
+this is rarely sufficient; users typically use only a small subset of
+the available commands, and it has proven all too common for a change
+to cause a significant regression that went unnoticed for some time.
+
+The @value{GDBN} testsuite uses the DejaGNU testing framework.
+DejaGNU is built using @code{Tcl} and @code{expect}. The tests
+themselves are calls to various @code{Tcl} procs; the framework runs all the
+procs and summarizes the passes and fails.
+
+@section Using the Testsuite
+
+@cindex running the test suite
+To run the testsuite, simply go to the @value{GDBN} object directory (or to the
+testsuite's objdir) and type @code{make check}. This just sets up some
+environment variables and invokes DejaGNU's @code{runtest} script. While
+the testsuite is running, you'll get mentions of which test file is in use,
+and a mention of any unexpected passes or fails. When the testsuite is
+finished, you'll get a summary that looks like this:
+
+@example
+ === gdb Summary ===
+
+# of expected passes 6016
+# of unexpected failures 58
+# of unexpected successes 5
+# of expected failures 183
+# of unresolved testcases 3
+# of untested testcases 5
+@end example
+
+The ideal test run consists of expected passes only; however, reality
+conspires to keep us from this ideal. Unexpected failures indicate
+real problems, whether in @value{GDBN} or in the testsuite. Expected
+failures are still failures, but ones which have been decided are too
+hard to deal with at the time; for instance, a test case might work
+everywhere except on AIX, and there is no prospect of the AIX case
+being fixed in the near future. Expected failures should not be added
+lightly, since you may be masking serious bugs in @value{GDBN}.
+Unexpected successes are expected fails that are passing for some
+reason, while unresolved and untested cases often indicate some minor
+catastrophe, such as the compiler being unable to deal with a test
+program.
+
+When making any significant change to @value{GDBN}, you should run the
+testsuite before and after the change, to confirm that there are no
+regressions. Note that truly complete testing would require that you
+run the testsuite with all supported configurations and a variety of
+compilers; however this is more than really necessary. In many cases
+testing with a single configuration is sufficient. Other useful
+options are to test one big-endian (Sparc) and one little-endian (x86)
+host, a cross config with a builtin simulator (powerpc-eabi,
+mips-elf), or a 64-bit host (Alpha).
+
+If you add new functionality to @value{GDBN}, please consider adding
+tests for it as well; this way future @value{GDBN} hackers can detect
+and fix their changes that break the functionality you added.
+Similarly, if you fix a bug that was not previously reported as a test
+failure, please add a test case for it. Some cases are extremely
+difficult to test, such as code that handles host OS failures or bugs
+in particular versions of compilers, and it's OK not to try to write
+tests for all of those.
+
+@section Testsuite Organization
+
+@cindex test suite organization
+The testsuite is entirely contained in @file{gdb/testsuite}. While the
+testsuite includes some makefiles and configury, these are very minimal,
+and used for little besides cleaning up, since the tests themselves
+handle the compilation of the programs that @value{GDBN} will run. The file
+@file{testsuite/lib/gdb.exp} contains common utility procs useful for
+all @value{GDBN} tests, while the directory @file{testsuite/config} contains
+configuration-specific files, typically used for special-purpose
+definitions of procs like @code{gdb_load} and @code{gdb_start}.
+
+The tests themselves are to be found in @file{testsuite/gdb.*} and
+subdirectories of those. The names of the test files must always end
+with @file{.exp}. DejaGNU collects the test files by wildcarding
+in the test directories, so both subdirectories and individual files
+get chosen and run in alphabetical order.
+
+The following table lists the main types of subdirectories and what they
+are for. Since DejaGNU finds test files no matter where they are
+located, and since each test file sets up its own compilation and
+execution environment, this organization is simply for convenience and
+intelligibility.
+
+@table @file
+@item gdb.base
+This is the base testsuite. The tests in it should apply to all
+configurations of @value{GDBN} (but generic native-only tests may live here).
+The test programs should be in the subset of C that is valid K&R,
+ANSI/ISO, and C++ (@code{#ifdef}s are allowed if necessary, for instance
+for prototypes).
+
+@item gdb.@var{lang}
+Language-specific tests for any language @var{lang} besides C. Examples are
+@file{gdb.c++} and @file{gdb.java}.
+
+@item gdb.@var{platform}
+Non-portable tests. The tests are specific to a specific configuration
+(host or target), such as HP-UX or eCos. Example is @file{gdb.hp}, for
+HP-UX.
+
+@item gdb.@var{compiler}
+Tests specific to a particular compiler. As of this writing (June
+1999), there aren't currently any groups of tests in this category that
+couldn't just as sensibly be made platform-specific, but one could
+imagine a @file{gdb.gcc}, for tests of @value{GDBN}'s handling of GCC
+extensions.
+
+@item gdb.@var{subsystem}
+Tests that exercise a specific @value{GDBN} subsystem in more depth. For
+instance, @file{gdb.disasm} exercises various disassemblers, while
+@file{gdb.stabs} tests pathways through the stabs symbol reader.
+@end table
+
+@section Writing Tests
+@cindex writing tests
+
+In many areas, the @value{GDBN} tests are already quite comprehensive; you
+should be able to copy existing tests to handle new cases.
+
+You should try to use @code{gdb_test} whenever possible, since it
+includes cases to handle all the unexpected errors that might happen.
+However, it doesn't cost anything to add new test procedures; for
+instance, @file{gdb.base/exprs.exp} defines a @code{test_expr} that
+calls @code{gdb_test} multiple times.
+
+Only use @code{send_gdb} and @code{gdb_expect} when absolutely
+necessary, such as when @value{GDBN} has several valid responses to a command.
+
+The source language programs do @emph{not} need to be in a consistent
+style. Since @value{GDBN} is used to debug programs written in many different
+styles, it's worth having a mix of styles in the testsuite; for
+instance, some @value{GDBN} bugs involving the display of source lines would
+never manifest themselves if the programs used GNU coding style
+uniformly.
+
+@node Hints
+
+@chapter Hints
+
+Check the @file{README} file, it often has useful information that does not
+appear anywhere else in the directory.
+
+@menu
+* Getting Started:: Getting started working on @value{GDBN}
+* Debugging GDB:: Debugging @value{GDBN} with itself
+@end menu
+
+@node Getting Started,,, Hints
+
+@section Getting Started
+
+@value{GDBN} is a large and complicated program, and if you first starting to
+work on it, it can be hard to know where to start. Fortunately, if you
+know how to go about it, there are ways to figure out what is going on.
+
+This manual, the @value{GDBN} Internals manual, has information which applies
+generally to many parts of @value{GDBN}.
+
+Information about particular functions or data structures are located in
+comments with those functions or data structures. If you run across a
+function or a global variable which does not have a comment correctly
+explaining what is does, this can be thought of as a bug in @value{GDBN}; feel
+free to submit a bug report, with a suggested comment if you can figure
+out what the comment should say. If you find a comment which is
+actually wrong, be especially sure to report that.
+
+Comments explaining the function of macros defined in host, target, or
+native dependent files can be in several places. Sometimes they are
+repeated every place the macro is defined. Sometimes they are where the
+macro is used. Sometimes there is a header file which supplies a
+default definition of the macro, and the comment is there. This manual
+also documents all the available macros.
+@c (@pxref{Host Conditionals}, @pxref{Target
+@c Conditionals}, @pxref{Native Conditionals}, and @pxref{Obsolete
+@c Conditionals})
+
+Start with the header files. Once you have some idea of how
+@value{GDBN}'s internal symbol tables are stored (see @file{symtab.h},
+@file{gdbtypes.h}), you will find it much easier to understand the
+code which uses and creates those symbol tables.
+
+You may wish to process the information you are getting somehow, to
+enhance your understanding of it. Summarize it, translate it to another
+language, add some (perhaps trivial or non-useful) feature to @value{GDBN}, use
+the code to predict what a test case would do and write the test case
+and verify your prediction, etc. If you are reading code and your eyes
+are starting to glaze over, this is a sign you need to use a more active
+approach.
+
+Once you have a part of @value{GDBN} to start with, you can find more
+specifically the part you are looking for by stepping through each
+function with the @code{next} command. Do not use @code{step} or you
+will quickly get distracted; when the function you are stepping through
+calls another function try only to get a big-picture understanding
+(perhaps using the comment at the beginning of the function being
+called) of what it does. This way you can identify which of the
+functions being called by the function you are stepping through is the
+one which you are interested in. You may need to examine the data
+structures generated at each stage, with reference to the comments in
+the header files explaining what the data structures are supposed to
+look like.
+
+Of course, this same technique can be used if you are just reading the
+code, rather than actually stepping through it. The same general
+principle applies---when the code you are looking at calls something
+else, just try to understand generally what the code being called does,
+rather than worrying about all its details.
+
+@cindex command implementation
+A good place to start when tracking down some particular area is with
+a command which invokes that feature. Suppose you want to know how
+single-stepping works. As a @value{GDBN} user, you know that the
+@code{step} command invokes single-stepping. The command is invoked
+via command tables (see @file{command.h}); by convention the function
+which actually performs the command is formed by taking the name of
+the command and adding @samp{_command}, or in the case of an
+@code{info} subcommand, @samp{_info}. For example, the @code{step}
+command invokes the @code{step_command} function and the @code{info
+display} command invokes @code{display_info}. When this convention is
+not followed, you might have to use @code{grep} or @kbd{M-x
+tags-search} in emacs, or run @value{GDBN} on itself and set a
+breakpoint in @code{execute_command}.
+
+@cindex @code{bug-gdb} mailing list
+If all of the above fail, it may be appropriate to ask for information
+on @code{bug-gdb}. But @emph{never} post a generic question like ``I was
+wondering if anyone could give me some tips about understanding
+@value{GDBN}''---if we had some magic secret we would put it in this manual.
+Suggestions for improving the manual are always welcome, of course.
+
+@node Debugging GDB,,,Hints
+
+@section Debugging @value{GDBN} with itself
+@cindex debugging @value{GDBN}
+
+If @value{GDBN} is limping on your machine, this is the preferred way to get it
+fully functional. Be warned that in some ancient Unix systems, like
+Ultrix 4.2, a program can't be running in one process while it is being
+debugged in another. Rather than typing the command @kbd{@w{./gdb
+./gdb}}, which works on Suns and such, you can copy @file{gdb} to
+@file{gdb2} and then type @kbd{@w{./gdb ./gdb2}}.
+
+When you run @value{GDBN} in the @value{GDBN} source directory, it will read a
+@file{.gdbinit} file that sets up some simple things to make debugging
+gdb easier. The @code{info} command, when executed without a subcommand
+in a @value{GDBN} being debugged by gdb, will pop you back up to the top level
+gdb. See @file{.gdbinit} for details.
+
+If you use emacs, you will probably want to do a @code{make TAGS} after
+you configure your distribution; this will put the machine dependent
+routines for your local machine where they will be accessed first by
+@kbd{M-.}
+
+Also, make sure that you've either compiled @value{GDBN} with your local cc, or
+have run @code{fixincludes} if you are compiling with gcc.
+
+@section Submitting Patches
+
+@cindex submitting patches
+Thanks for thinking of offering your changes back to the community of
+@value{GDBN} users. In general we like to get well designed enhancements.
+Thanks also for checking in advance about the best way to transfer the
+changes.
+
+The @value{GDBN} maintainers will only install ``cleanly designed'' patches.
+This manual summarizes what we believe to be clean design for @value{GDBN}.
+
+If the maintainers don't have time to put the patch in when it arrives,
+or if there is any question about a patch, it goes into a large queue
+with everyone else's patches and bug reports.
+
+@cindex legal papers for code contributions
+The legal issue is that to incorporate substantial changes requires a
+copyright assignment from you and/or your employer, granting ownership
+of the changes to the Free Software Foundation. You can get the
+standard documents for doing this by sending mail to @code{gnu@@gnu.org}
+and asking for it. We recommend that people write in "All programs
+owned by the Free Software Foundation" as "NAME OF PROGRAM", so that
+changes in many programs (not just @value{GDBN}, but GAS, Emacs, GCC,
+etc) can be
+contributed with only one piece of legalese pushed through the
+bureaucracy and filed with the FSF. We can't start merging changes until
+this paperwork is received by the FSF (their rules, which we follow
+since we maintain it for them).
+
+Technically, the easiest way to receive changes is to receive each
+feature as a small context diff or unidiff, suitable for @code{patch}.
+Each message sent to me should include the changes to C code and
+header files for a single feature, plus @file{ChangeLog} entries for
+each directory where files were modified, and diffs for any changes
+needed to the manuals (@file{gdb/doc/gdb.texinfo} or
+@file{gdb/doc/gdbint.texinfo}). If there are a lot of changes for a
+single feature, they can be split down into multiple messages.
+
+In this way, if we read and like the feature, we can add it to the
+sources with a single patch command, do some testing, and check it in.
+If you leave out the @file{ChangeLog}, we have to write one. If you leave
+out the doc, we have to puzzle out what needs documenting. Etc., etc.
+
+The reason to send each change in a separate message is that we will not
+install some of the changes. They'll be returned to you with questions
+or comments. If we're doing our job correctly, the message back to you
+will say what you have to fix in order to make the change acceptable.
+The reason to have separate messages for separate features is so that
+the acceptable changes can be installed while one or more changes are
+being reworked. If multiple features are sent in a single message, we
+tend to not put in the effort to sort out the acceptable changes from
+the unacceptable, so none of the features get installed until all are
+acceptable.
+
+If this sounds painful or authoritarian, well, it is. But we get a lot
+of bug reports and a lot of patches, and many of them don't get
+installed because we don't have the time to finish the job that the bug
+reporter or the contributor could have done. Patches that arrive
+complete, working, and well designed, tend to get installed on the day
+they arrive. The others go into a queue and get installed as time
+permits, which, since the maintainers have many demands to meet, may not
+be for quite some time.
+
+Please send patches directly to
+@email{gdb-patches@@sourceware.cygnus.com, the @value{GDBN} maintainers}.
+
+@section Obsolete Conditionals
+@cindex obsolete code
+
+Fragments of old code in @value{GDBN} sometimes reference or set the following
+configuration macros. They should not be used by new code, and old uses
+should be removed as those parts of the debugger are otherwise touched.
@table @code
@item STACK_END_ADDR
This macro used to define where the end of the stack appeared, for use
in interpreting core file formats that don't record this address in the
-core file itself. This information is now configured in BFD, and GDB
-gets the info portably from there. The values in GDB's configuration
+core file itself. This information is now configured in BFD, and @value{GDBN}
+gets the info portably from there. The values in @value{GDBN}'s configuration
files should be moved into BFD configuration files (if needed there),
-and deleted from all of GDB's config files.
+and deleted from all of @value{GDBN}'s config files.
Any @file{@var{foo}-xdep.c} file that references STACK_END_ADDR
is so old that it has never been converted to use BFD. Now that's old!
+
+@item PYRAMID_CONTROL_FRAME_DEBUGGING
+pyr-xdep.c
+@item PYRAMID_CORE
+pyr-xdep.c
+@item PYRAMID_PTRACE
+pyr-xdep.c
+
+@item REG_STACK_SEGMENT
+exec.c
+
@end table
-@node XCOFF
-@chapter The XCOFF Object File Format
+@node Index
+@unnumbered Index
-The IBM RS/6000 running AIX uses an object file format called xcoff.
-The COFF sections, symbols, and line numbers are used, but debugging
-symbols are dbx-style stabs whose strings are located in the
-@samp{.debug} section (rather than the string table). Files are
-indicated with a @samp{C_FILE} symbol (.file) which is analogous to
-@samp{N_SO}; include files are delimited with @samp{C_BINCL} (.bi) and
-@samp{C_EINCL} (.ei) which correspond to @samp{N_SOL} rather than Sun's
-@samp{N_BINCL} (that is, they don't nest and there is no equivalent to
-N_EXCL). The values of the @samp{C_BINCL} and @samp{C_EINCL} symbols
-are offsets into the executable file which point to the beginning and
-the end of the portion of the linetable which correspond to this include
-file (warning: C_EINCL is inclusive not exclusive like most end of
-something pointers). Other differences from standard stabs include the
-use of negative type numbers for builtin types.
-
-The shared library scheme has a nice clean interface for figuring out
-what shared libraries are in use, but the catch is that everything which
-refers to addresses (symbol tables and breakpoints at least) needs to be
-relocated for both shared libraries and the main executable. At least
-using the standard mechanism this can only be done once the program has
-been run (or the core file has been read).
+@printindex cp
+@c TeX can handle the contents at the start but makeinfo 3.12 can not
+@ifinfo
@contents
+@end ifinfo
+@ifhtml
+@contents
+@end ifhtml
+
@bye
projects / deliverable / binutils-gdb.git / blobdiff