-\input texinfo
+\input texinfo @c -*- texinfo -*-
@setfilename gdbint.info
-
-@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 1990-1999 Free Software Foundation, Inc.
+This file documents the internals of the GNU debugger @value{GDBN}.
+Copyright 1990,1991,1992,1993,1994,1996,1998,1999,2000,2001,2002
+ Free Software Foundation, Inc.
Contributed by Cygnus Solutions. Written by John Gilmore.
Second Edition by Stan Shebs.
-Permission is granted to make and distribute verbatim copies of this
-manual provided the copyright notice and this permission notice are
-preserved on all copies.
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.1 or
+any later version published by the Free Software Foundation; with no
+Invariant Sections, with the Front-Cover Texts being ``A GNU Manual,''
+and with the Back-Cover Texts as in (a) below.
-@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).
+(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{GDB Internals}
+@title @value{GDBN} Internals
@subtitle{A guide to the internals of the GNU debugger}
@author John Gilmore
@author Cygnus Solutions
@end tex
@vskip 0pt plus 1filll
-Copyright @copyright{} 1990-1999 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 no
+Invariant Sections, 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
+@contents
+
@node Top
@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, GDB. It
-includes description of GDB's key algorithms and operations, as well
-as the mechanisms that adapt GDB to specific hosts and targets.
+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
* Requirements::
* Overall Structure::
* Algorithms::
* User Interface::
+* libgdb::
* Symbol Handling::
* Language Support::
* Host Definition::
* Support Libraries::
* Coding::
* Porting GDB::
+* Releasing GDB::
* Testsuite::
* Hints::
+
+* GNU Free Documentation License:: The license for this documentation
+* Index::
@end menu
@node Requirements
@chapter Requirements
+@cindex requirements for @value{GDBN}
Before diving into the internals, you should understand the formal
-requirements and other expectations for GDB. Although some of these may
-seem obvious, there have been proposals for GDB that have run counter to
-these requirements.
+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.
-First of all, GDB 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.
+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.
-GDB is an interactive tool. Although a batch mode is available, GDB's
-primary role is to interact with a human programmer.
+@value{GDBN} is an interactive tool. Although a batch mode is
+available, @value{GDBN}'s primary role is to interact with a human
+programmer.
-GDB 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.
+@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.
-GDB 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.
+@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.
-GDB 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.
+@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.
-GDB should be able to run everywhere. No other debugger is available
-for even half as many configurations as GDB supports.
+@value{GDBN} should be able to run everywhere. No other debugger is
+available for even half as many configurations as @value{GDBN}
+supports.
@node Overall Structure
@chapter Overall Structure
-GDB consists of three major subsystems: user interface, symbol handling
-(the ``symbol side''), and target system handling (the ``target side'').
+@value{GDBN} consists of three major subsystems: user interface,
+symbol handling (the @dfn{symbol side}), and target system handling (the
+@dfn{target side}).
-Ther user interface consists of several actual interfaces, plus
+The user interface consists of several actual interfaces, plus
supporting code.
The symbol side consists of object file readers, debugging info
@section The Symbol Side
-The symbolic side of GDB can be thought of as ``everything you can do in
-GDB without having a live program running''. For instance, you can look
-at the types of variables, and evaluate many kinds of expressions.
+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
-The target side of GDB 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.
+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.
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, GDB will use symbolic info to present addresses
+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.
@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.
@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
+When you want to make @value{GDBN} work ``native'' on a particular machine, you
have to include all three kinds of information.
@node Algorithms
@chapter Algorithms
+@cindex algorithms
-GDB 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.
+@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.
@section Frames
-A frame is a construct that GDB uses to keep track of calling and called
-functions.
+@cindex frame
+@cindex call stack frame
+A frame is a construct that @value{GDBN} uses to keep track of calling
+and called functions.
+@findex create_new_frame
+@vindex FRAME_FP
@code{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:
+machine-independent part of @value{GDBN}, except that it is used when
+setting up a new frame from scratch, as follows:
-@example
- create_new_frame (read_register (FP_REGNUM), read_pc ()));
-@end example
+@smallexample
+create_new_frame (read_register (FP_REGNUM), read_pc ()));
+@end smallexample
+@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.
defined; that is where you should use the @code{FP_REGNUM} value, if
your frames are nonstandard.)
-Given a GDB frame, define @code{FRAME_CHAIN} to 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.
+@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 GDB. 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 GDB's point of view
-they work the same; GDB need not do nothing more than set the breakpoint
-and wait for something to happen.
+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, GDB will start trying to
-set software breakpoints.
-
-Software breakpoints require GDB to do somewhat more work. The basic
-theory is that GDB will replace a program instruction a trap, illegal
-divide, or some other instruction that will cause an exception, and then
-when it's encountered, GDB will take the exception and stop the program.
-When the user says to continue, GDB will restore the original
+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 always 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 writeable, so this technique won't work on programs in ROM. It
+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 the situation would be highly unusual.
+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
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}.
@section Longjmp Support
-GDB has support for figuring out that the target is doing a
+@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 @code{maint info breakpoint} command.
+which are visible in the output of the @samp{maint info breakpoint}
+command.
+@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{xyz}.h} file. Look in @file{tm-sun4os4.h} and
+@file{tm-@var{target}.h} file. Look in @file{tm-sun4os4.h} and
@file{sparc-tdep.c} for examples of how to do this.
+@section Watchpoints
+@cindex watchpoints
+
+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.
+
+@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:
+
+@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.
+
+@item
+The value of the expression to be watched depends on data held in
+registers (as opposed to memory).
+
+@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.
+
+@item
+No hardware-assisted watchpoints provided by the target
+implementation.
+@end itemize
+
+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.
+
+@value{GDBN} uses several macros and primitives to support hardware
+watchpoints:
+
+@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:
+
+@smallexample
+ 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 smallexample
+
+@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
+
+@subsection x86 Watchpoints
+@cindex x86 debug registers
+@cindex watchpoints, on x86
+
+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}.
+
+To use the generic x86 watchpoint support, a port should do the
+following:
+
+@itemize @bullet
+@findex I386_USE_GENERIC_WATCHPOINTS
+@item
+Define the macro @code{I386_USE_GENERIC_WATCHPOINTS} somewhere in the
+target-dependent headers.
+
+@item
+Include the @file{config/i386/nm-i386.h} header file @emph{after}
+defining @code{I386_USE_GENERIC_WATCHPOINTS}.
+
+@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}).
+
+@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
+
+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:
+
+@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
+
+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:
+
+@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 mirrored
+value to @var{addr}, sets the mirrored 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 mirrored value of the debug register and its read/write and
+length bits in the mirrored 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
+
+@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.
+
+@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
+
@node User Interface
@chapter User Interface
-GDB has several user interfaces. Although the command-line interface
+@value{GDBN} has several user interfaces. Although the command-line interface
is the most common and most familiar, there are others.
@section Command Interpreter
-The command interpreter in GDB is fairly simple. It is designed to
+@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.
-For instance, the @code{set} command just starts a lookup on the
-@code{setlist} command list, while @code{set thread} recurses
+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}.
+@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.
+place to add commands is in the @code{_initialize_@var{xyz}} routines at
+the ends of most source files.
+
+@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.
+
+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.
+
+@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>.
+
+@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.
+
+@subsection Overview and Terminology
+
+In general, execution of each @value{GDBN} command produces some sort
+of output, and can even generate an input request.
+
+Output can be generated for the following purposes:
+
+@itemize @bullet
+@item
+to display a @emph{result} of an operation;
+
+@item
+to convey @emph{info} or produce side-effects of a requested
+operation;
+
+@item
+to provide a @emph{notification} of an asynchronous event (including
+progress indication of a prolonged asynchronous operation);
+
+@item
+to display @emph{error messages} (including warnings);
+
+@item
+to show @emph{debug data};
+
+@item
+to @emph{query} or prompt a user for input (a special case).
+@end itemize
+
+@noindent
+This section mainly concentrates on how to build result output,
+although some of it also applies to other kinds of output.
+
+Generation of output that displays the results of an operation
+involves one or more of the following:
+
+@itemize @bullet
+@item
+output of the actual data
+
+@item
+formatting the output as appropriate for console output, to make it
+easily readable by humans
+
+@item
+machine oriented formatting--a more terse formatting to allow for easy
+parsing by programs which read @value{GDBN}'s output
+
+@item
+annotation, whose purpose is to help legacy GUIs to identify interesting
+parts in the output
+@end itemize
+
+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.
+
+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:
+
+@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
+
+
+@subsection General Conventions
+
+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.
+
+The first parameter is always the @code{ui_out} vector object, a pointer
+to a @code{struct ui_out}.
+
+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.
+
+When a character string argument is not used in a @code{ui_out} function
+call, a @code{NULL} pointer has to be supplied instead.
+
+
+@subsection Table, Tuple and List Functions
+
+@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.
+
+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.
+
+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.
+
+@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.
+
+The overall structure of the table output code is something like this:
+
+@smallexample
+ 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 smallexample
+
+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.
+
+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:
+
+@smallexample
+ 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 smallexample
+
+Here's the new version:
+
+@smallexample
+ 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 smallexample
+
+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:
+
+@smallexample
+ 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 smallexample
+
+This is the new version:
+
+@smallexample
+ 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 smallexample
+
+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:
+
+@smallexample
+ annotate_field (5);
+ print_expression (b->exp, gdb_stdout);
+@end smallexample
+
+The new version is:
+
+@smallexample
+ 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 smallexample
+
+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:
+
+@smallexample
+ annotate_field (5);
+ if (b->dll_pathname == NULL)
+ printf_filtered ("<any library> ");
+ else
+ printf_filtered ("library \"%s\" ", b->dll_pathname);
+@end smallexample
+
+It became:
+
+@smallexample
+ 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 smallexample
+
+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:
+
+@smallexample
+ annotate_field (5);
+ if (b->forked_inferior_pid != 0)
+ printf_filtered ("process %d ", b->forked_inferior_pid);
+@end smallexample
+
+It became:
+
+@smallexample
+ 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 smallexample
+
+Here's an example of using @code{ui_out_field_string}. The original
+code was:
+
+@smallexample
+ annotate_field (5);
+ if (b->exec_pathname != NULL)
+ printf_filtered ("program \"%s\" ", b->exec_pathname);
+@end smallexample
+
+It became:
+
+@smallexample
+ 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 smallexample
+
+Finally, here's an example of printing an address. The original code:
+
+@smallexample
+ annotate_field (4);
+ printf_filtered ("%s ",
+ local_hex_string_custom ((unsigned long) b->address, "08l"));
+@end smallexample
+
+It became:
+
+@smallexample
+ annotate_field (4);
+ ui_out_field_core_addr (uiout, "Address", b->address);
+@end smallexample
+
@section Console Printing
@section TUI
-@section libgdb
+@node libgdb
+
+@chapter libgdb
+
+@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.
+
+@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.
+
+Since @code{libgdb} development is on-going, its architecture is still
+evolving. The following components have so far been identified:
+
+@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
+
+The model that ties these components together is described below.
+
+@section The @code{libgdb} Model
+
+A client of @code{libgdb} interacts with the library in two ways.
+
+@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
-@code{libgdb} was an abortive project of years ago. The theory was to
-provide an API to GDB's functionality.
+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
+
+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.
+
+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:
+
+@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
+
+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 GDB's operation. Symbols include variables,
+Symbols are a key part of @value{GDBN}'s operation. Symbols include variables,
functions, and types.
@section Symbol Reading
-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 @code{symbol-file}
-command), and it can also read more symbols via the ``add-file'' and
-``load'' commands, or while reading symbols from shared libraries.
-
-Symbol files are initially opened by code in @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.
-
-Symbol reading modules identify themselves to GDB by calling
+@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,
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{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
+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
@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{xyz}_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{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{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
In addition, if a symbol-reading module creates psymtabs when
@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 GDB symbol-handling code.
+from any point in the @value{GDBN} symbol-handling code.
@table @code
@item @var{xyz}_psymtab_to_symtab (struct partial_symtab *pst)
-Called from @code{psymtab_to_symtab} (or the PSYMTAB_TO_SYMTAB macro) if
+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, pst->readin should have been set to 1, and
-pst->symtab should contain a pointer to the new corresponding symtab, or
+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
-GDB has three types of symbol tables.
+@value{GDBN} has three types of symbol tables:
@itemize @bullet
-
-@item full symbol tables (symtabs). These contain the main information
-about symbols and addresses.
-
-@item partial symbol tables (psymtabs). These contain enough
+@cindex full symbol table
+@cindex symtabs
+@item
+Full symbol tables (@dfn{symtabs}). These contain the main
+information about symbols and addresses.
+
+@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.
-@item minimal symbol tables (msymtabs). These contain information
+@cindex minimal symbol table
+@cindex minsymtabs
+@item
+Minimal symbol tables (@dfn{msymtabs}). These contain information
gleaned from non-debugging symbols.
-
@end itemize
+@cindex partial symbol table
This section describes partial symbol tables.
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
+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
+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.
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.
+types, and @code{enum} values declared at file scope.
The psymtab also contains the range of instruction addresses that the
full symbol table would represent.
+@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:
@itemize @bullet
-
-@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.
-
-@item by its name
+@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.
+
+@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
+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
either, so types need not appear, unless they will be referenced by
name.
-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 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
+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,
@section Types
-Fundamental Types (e.g., FT_VOID, FT_BOOLEAN).
+@unnumberedsubsec Fundamental Types (e.g., @code{FT_VOID}, @code{FT_BOOLEAN}).
-These are the fundamental types that GDB uses internally. Fundamental
+@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 gdb knows about for all the languages that GDB knows about.
+that @value{GDBN} knows about for all the languages that @value{GDBN}
+knows about.
-Type Codes (e.g., TYPE_CODE_PTR, TYPE_CODE_ARRAY).
+@unnumberedsubsec Type Codes (e.g., @code{TYPE_CODE_PTR}, @code{TYPE_CODE_ARRAY}).
-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.
+@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.
-Builtin Types (e.g., builtin_type_void, builtin_type_char).
+@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 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.
+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
-The @file{a.out} format is the original file format for Unix. It
-consists of three sections: text, data, and bss, which are for program
-code, initialized data, and uninitialized data, respectively.
+@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 @file{a.out} format is so simple that it doesn't have any reserved
+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
-@file{adb}, which is a machine-language debugger.) The only debugging
-format for @file{a.out} is stabs, which is encoded as a set of normal
+@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 @file{a.out} reader is in @file{dbxread.c}.
+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.
@subsection ECOFF
+@cindex ECOFF format
ECOFF is an extended COFF originally introduced for Mips and Alpha
workstations.
@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 dbx-style stabs whose strings are located in the
-@samp{.debug} section (rather than the string table). For more
-information, see @xref{Top,,,stabs,The Stabs Debugging Format}.
+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}.
The shared library scheme has a clean interface for figuring out what
shared libraries are in use, but the catch is that everything which
@subsection PE
-Windows 95 and NT use the PE (Portable Executable) format for their
+@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.
-While BFD includes special PE support, GDB needs only the basic
+While BFD includes special PE support, @value{GDBN} needs only the basic
COFF reader.
@subsection ELF
+@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.
@subsection SOM
+@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).
@subsection Other File Formats
-Other file formats that have been supported by GDB include Netware
-Loadable Modules (@file{nlmread.c}.
+@cindex Netware Loadable Module format
+Other file formats that have been supported by @value{GDBN} include Netware
+Loadable Modules (@file{nlmread.c}).
@section Debugging File Formats
@subsection stabs
+@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.
@subsection COFF
+@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.
@subsection Mips debug (Third Eye)
+@cindex ECOFF debugging info
ECOFF includes a definition of a special debug format.
The file @file{mdebugread.c} implements reading for this format.
@subsection DWARF 1
+@cindex DWARF 1 debugging info
DWARF 1 is a debugging format that was originally designed to be
used with ELF in SVR4 systems.
@subsection DWARF 2
+@cindex DWARF 2 debugging info
DWARF 2 is an improved but incompatible version of DWARF 1.
The DWARF 2 reader is in @file{dwarf2read.c}.
@subsection SOM
+@cindex SOM debugging info
Like COFF, the SOM definition includes debugging information.
-@section Adding a New Symbol Reader to GDB
+@section Adding a New Symbol Reader to @value{GDBN}
-If you are using an existing object file format (a.out, COFF, ELF, etc),
+@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 you need to add a new object file format, you must first add it to
BFD. This is beyond the scope of this document.
You must then arrange for the BFD code to provide access to the
-debugging symbols. Generally GDB will have to call swapping routines
+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, GDB should not depend on the BFD
+information. As much as possible, @value{GDBN} should not depend on the BFD
internal data structures.
For some targets (e.g., COFF), there is a special transfer vector used
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/libxyz.h}, which is included by GDB.
+@file{bfd/lib@var{xyz}.h}, which is included by @value{GDBN}.
@node Language Support
@chapter Language Support
-GDB's language support is mainly driven by the symbol reader, although
-it is possible for the user to set the source language manually.
+@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.
-GDB chooses the source language by looking at the extension of the file
-recorded in the debug info; @code{.c} means C, @code{.f} means Fortran,
-etc. It may also use a special-purpose language identifier if the debug
-format supports it, such as DWARF.
+@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.
-@section Adding a Source Language to GDB
+@section Adding a Source Language to @value{GDBN}
-To add other languages to GDB's expression parser, follow the following
-steps:
+@cindex adding source language
+To add other languages to @value{GDBN}'s expression parser, follow the
+following steps:
@table @emph
@item Create the expression parser.
+@cindex expression parser
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
+building parsed expressions into a @code{union exp_element} list are in
@file{parse.c}.
+@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
-@emph{must} be included at the top of the YACC parser, to prevent the
+@strong{must} be included at the top of the YACC parser, to prevent the
various parsers from defining the same global names:
-@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
+@smallexample
+#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 smallexample
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
+@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
@item Add any evaluation routines, if necessary
+@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 @code{eval.c:evaluate_subexp()}. Add cases
+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
+@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
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 GDB is built for.
+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.
information, please set the language of the symtab in the symbol-reading
code.
-Add helper code to @code{expprint.c:print_subexp()} to handle any new
+@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.c:parse_exp_1()}.
+@code{parse_exp_1} (defined in @file{parse.c}).
@item Use macros to trim code
-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
+@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 GDB
+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 GDB at all.
+compiled form of your parser) is not linked into @value{GDBN} at all.
-See the file @file{configure.in} for how GDB is configured for different
-languages.
+See the file @file{configure.in} for how @value{GDBN} is configured
+for different languages.
@item Edit @file{Makefile.in}
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
@chapter Host Definition
-With the advent of autoconf, it's rarely necessary to have host
-definition machinery anymore.
+With the advent of Autoconf, it's rarely necessary to have host
+definition machinery anymore. The following information is provided,
+mainly, as an historical reference.
@section Adding a New Host
-Most of GDB's host configuration support happens via autoconf. It
-should be rare to need new host-specific definitions. GDB still uses
-the host-specific definitions and files listed below, but these mostly
-exist for historical reasons, and should eventually disappear.
-
-Several files control GDB's configuration for host systems:
+@cindex adding a new host
+@cindex host, adding
+@value{GDBN}'s host configuration support normally happens via Autoconf.
+New host-specific definitions should not be needed. Older hosts
+@value{GDBN} still use the host-specific definitions and files listed
+below, but these mostly exist for historical reasons, and will
+eventually disappear.
@table @file
-
@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}.
+This file once contained both host and native configuration information
+(@pxref{Native Debugging}) for the machine @var{xyz}. The host
+configuration information is now handed by Autoconf.
+
+Host configuration information included a definition of
+@code{XM_FILE=xm-@var{xyz}.h} and possibly definitions for @code{CC},
+@code{SYSV_DEFINE}, @code{XM_CFLAGS}, @code{XM_ADD_FILES},
+@code{XM_CLIBS}, @code{XM_CDEPS}, etc.; see @file{Makefile.in}.
+
+New host only configurations do not need this file.
@item gdb/config/@var{arch}/xm-@var{xyz}.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.
+This file once contained definitions and includes required when hosting
+gdb on machine @var{xyz}. Those definitions and includes are now
+handled by Autoconf.
-@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}.
+New host and native configurations do not need this file.
+
+@emph{Maintainer's note: Some hosts continue to use the @file{xm-xyz.h}
+file to define the macros @var{HOST_FLOAT_FORMAT},
+@var{HOST_DOUBLE_FORMAT} and @var{HOST_LONG_DOUBLE_FORMAT}. That code
+also needs to be replaced with either an Autoconf or run-time test.}
@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
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
@item ser-go32.c
This contains serial line support for 32-bit programs running under DOS,
-using the GO32 execution environment.
+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 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 (or if the meaning is not
-documented here, then one of the source files where they are used is
-indicated) are:
+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:
-@table @code
-
-@item GDBINIT_FILENAME
-The default name of GDB's initialization file (normally @file{.gdbinit}).
-
-@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}.
+@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.
the expansion of @code{SIGWINCH_HANDLER}.
@item ALIGN_STACK_ON_STARTUP
+@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 \r\n line endings of files
-which are "sourced" by gdb. It must be possible to open files in binary
+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
+@cindex prompt
The default value of the prompt string (normally @code{"(gdb) "}).
@item DEV_TTY
+@cindex terminal device
The name of the generic TTY device, defaults to @code{"/dev/tty"}.
@item FCLOSE_PROVIDED
@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
+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_SIGSETMASK
-Define this if the host system has job control, but does not define
-@code{sigsetmask()}. Currently, this is only true of the RS/6000.
-
@item HAVE_TERMIO
Define this if the host system has @code{termio.h}.
-@item HOST_BYTE_ORDER
-The ordering of bytes in the host. This must be defined to be either
-@code{BIG_ENDIAN} or @code{LITTLE_ENDIAN}.
-
@item INT_MAX
-@item INT_MIN
-@item LONG_MAX
-@item UINT_MAX
-@item ULONG_MAX
+@itemx INT_MIN
+@itemx LONG_MAX
+@itemx UINT_MAX
+@itemx ULONG_MAX
Values for host-side constants.
@item ISATTY
@code{CC_HAS_LONG_LONG}.
@item CC_HAS_LONG_LONG
-Define this if the host C compiler supports ``long long''. This is set
-by the configure script.
+@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 directive ``ll''. This is set by the configure script.
+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 ``long double''. This is
-set by the configure script.
+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 directive ``Lg''. This is set by the
-configure script.
+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 directive directive
-``Lg''. This is set by the configure script.
+float-point numbers via the scanf format conversion specifier
+@code{Lg}. This is set by the @code{configure} script.
@item LSEEK_NOT_LINEAR
Define this if @code{lseek (n)} does not necessarily move to byte number
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, 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.
+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 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 NEED_POSIX_SETPGID
-Define this to use the POSIX version of @code{setpgid} to determine
-whether job control is available.
-
@item NORETURN
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
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
-GDB 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 mmalloc library. This define is set when you
-configure with --with-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}. Note that on some systems,
-the C runtime makes calls to malloc prior to calling @code{main}, and if
+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 mmalloc, but must define
-NO_MMCHECK.
+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
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, gdb will issue a
+calls, and if it fails to install the functions, @value{GDBN} will issue a
warning. This is currently defined if you configure using
---with-mmalloc.
+@samp{--with-mmalloc}.
@item NO_SIGINTERRUPT
-Define this to indicate that siginterrupt() is not available.
-
-@item R_OK
-Define if this is not in a system .h file.
+@findex siginterrupt
+Define this to indicate that @code{siginterrupt} is not available.
@item SEEK_CUR
-@item SEEK_SET
-Define these to appropriate value for the system lseek(), if not already
+@itemx SEEK_SET
+Define these to appropriate value for the system @code{lseek}, if not already
defined.
@item STOP_SIGNAL
-This is the signal for stopping GDB. Defaults to SIGTSTP. (Only
-redefined for the Convex.)
+This is the signal for stopping @value{GDBN}. Defaults to
+@code{SIGTSTP}. (Only redefined for the Convex.)
@item USE_O_NOCTTY
-Define this if the interior's tty should be opened with the O_NOCTTY
+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.)
moment.)
@item lint
-Define this to help placate lint in some situations.
+Define this to help placate @code{lint} in some situations.
@item volatile
Define this to override the defaults of @code{__volatile__} or
@code{/**/}.
-
-@end table
+@end ftable
@node Target Architecture Definition
@chapter Target Architecture Definition
-GDB's target architecture defines what sort of machine-language programs
-GDB can work with, and how it works with them.
+@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.
-At present, the target architecture definition consists of a number of C
-macros.
+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
-GDB's model of the target machine is rather simple. GDB assumes the
-machine includes a bank of registers and a block of memory. Each
-register may have a different size.
+@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 (struct value *@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:
-GDB 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.
+@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
+
+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.
+
+Your architecture may define the following macros to request
+conversions between the raw and virtual format:
+
+@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
-GDB can handle big-endian, little-endian, and bi-endian architectures.
@section Frame Interpretation
@table @code
@item ADDITIONAL_OPTIONS
-@item ADDITIONAL_OPTION_CASES
-@item ADDITIONAL_OPTION_HANDLER
-@item ADDITIONAL_OPTION_HELP
+@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 GDB. They are currently used only for the unsupported
+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 zeros those bits in @var{addr}. This is only used for
+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
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
+@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, GDB will probably not compile, let alone run correctly.
-This is currently used only for the unsupported i960 Nindy target, and
-should not be used in any other configuration.
+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
-Define if the compiler promotes a short or char parameter to an int, but
-still reports the parameter as its original type, rather than the
-promoted type.
+@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
-Define this if GDB should believe the type of a short argument when
-compiled by pcc, but look within a full int space to get its value.
-Only defined for Sun-3 at present.
+@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
-Define this if the numbering of bits in the targets does *not* match the
+@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 order, 0 means little-endian.
+are numbered in a big-endian bit order, 0 means little-endian.
@item BREAKPOINT
+@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.
-@var{BREAKPOINT} has been deprecated in favour of
-@var{BREAKPOINT_FROM_PC}.
+@code{BREAKPOINT} has been deprecated in favor of
+@code{BREAKPOINT_FROM_PC}.
@item BIG_BREAKPOINT
-@item LITTLE_BREAKPOINT
+@itemx LITTLE_BREAKPOINT
+@findex LITTLE_BREAKPOINT
+@findex BIG_BREAKPOINT
Similar to BREAKPOINT, but used for bi-endian targets.
-@var{BIG_BREAKPOINT} and @var{LITTLE_BREAKPOINT} have been deprecated in
-favour of @var{BREAKPOINT_FROM_PC}.
+@code{BIG_BREAKPOINT} and @code{LITTLE_BREAKPOINT} have been deprecated in
+favor of @code{BREAKPOINT_FROM_PC}.
@item REMOTE_BREAKPOINT
-@item LITTLE_REMOTE_BREAKPOINT
-@item BIG_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.
-@var{BIG_REMOTE_BREAKPOINT} and @var{LITTLE_REMOTE_BREAKPOINT} have been
-deprecated in favour of @var{BREAKPOINT_FROM_PC}.
-
-@item BREAKPOINT_FROM_PC (pcptr, lenptr)
+@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
-*lenptr, and adjusts pc (if necessary) to point to the actual memory
-location where the breakpoint should be inserted.
+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
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
-A C expresson that is non-zero when the target suports inferior function
+@findex CALL_DUMMY_P
+A C expression that is non-zero when the target supports inferior function
calls.
@item CALL_DUMMY_WORDS
-Pointer to an array of @var{LONGEST} words of data containing
-host-byte-ordered @var{REGISTER_BYTES} sized values that partially
+@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 favour of a macro that uses target-byte-ordered
+Should be deprecated in favor of a macro that uses target-byte-ordered
data.
@item SIZEOF_CALL_DUMMY_WORDS
-The size of @var{CALL_DUMMY_WORDS}. When @var{CALL_DUMMY_P} this must
-return a positive value. See also @var{CALL_DUMMY_LENGTH}.
+@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
-A static initializer for @var{CALL_DUMMY_WORDS}. Deprecated.
+@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
+@findex CALL_DUMMY_STACK_ADJUST
Stack adjustment needed when performing an inferior function call.
-Should be deprecated in favor of something like @var{STACK_ALIGN}.
+Should be deprecated in favor of something like @code{STACK_ALIGN}.
@item CALL_DUMMY_STACK_ADJUST_P
-Predicate for use of @var{CALL_DUMMY_STACK_ADJUST}.
+@findex CALL_DUMMY_STACK_ADJUST_P
+Predicate for use of @code{CALL_DUMMY_STACK_ADJUST}.
-Should be deprecated in favor of something like @var{STACK_ALIGN}.
+Should be deprecated in favor of something like @code{STACK_ALIGN}.
-@item CANNOT_FETCH_REGISTER (regno)
+@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 (regno)
+@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, GDB
-will assume that all registers may be written.
+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
-@item CLEAR_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
-Define this to expand into the character that G++ uses to distinguish
+@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
+@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
+@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
-BREAKPOINT, though not always. For most targets this value will be 0.
+@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 addr
+@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
+@findex DO_REGISTERS_INFO
If defined, use this to print the value of a register or all registers.
+@item PRINT_FLOAT_INFO()
+#findex PRINT_FLOAT_INFO
+If defined, then the @samp{info float} command will print information about
+the processor's floating point unit.
+
+@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
-This is an expression that should designate the end of the text section
-(? FIXME ?)
+@findex END_OF_TEXT_DEFAULT
+This is an expression that should designate the end of the text section.
+@c (? FIXME ?)
-@item EXTRACT_RETURN_VALUE(type,regbuf,valbuf)
+@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(regbuf)
-When @var{EXTRACT_STRUCT_VALUE_ADDRESS_P} this is used to to extract
-from an array @var{regbuf} (containing the raw register state) the
-address in which a function should return its structure value, as a
-CORE_ADDR (or an expression that can be used as one).
+@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
-Predicate for @var{EXTRACT_STRUCT_VALUE_ADDRESS}.
+@item EXTRACT_STRUCT_VALUE_ADDRESS_P()
+@findex EXTRACT_STRUCT_VALUE_ADDRESS_P
+Predicate for @code{EXTRACT_STRUCT_VALUE_ADDRESS}.
@item FLOAT_INFO
-If defined, then the `info float' command will print information about
-the processor's floating point unit.
+@findex FLOAT_INFO
+Deprecated in favor of @code{PRINT_FLOAT_INFO}.
@item FP_REGNUM
+@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.
+This should only need to be defined if @code{TARGET_READ_FP} is not
+defined.
-@item FRAMELESS_FUNCTION_INVOCATION(fi)
+@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
-stack.c
+@findex FRAME_ARGS_ADDRESS_CORRECT
+See @file{stack.c}.
-@item FRAME_CHAIN(frame)
+@item FRAME_CHAIN(@var{frame})
+@findex FRAME_CHAIN
Given @var{frame}, return a pointer to the calling frame.
-@item FRAME_CHAIN_COMBINE(chain,frame)
-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:
-@item FRAME_CHAIN_VALID(chain,thisframe)
+@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
-Define this to be an expression that returns zero if the given frame is
-an outermost frame, with no caller, and nonzero otherwise. Three common
-definitions are available. @code{default_frame_chain_valid} (the
-default) is nonzero if the chain pointer is nonzero and given frame's PC
-is not inside the startup file (such as @file{crt0.o}).
-@code{alternate_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 FRAME_INIT_SAVED_REGS(frame)
+@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}.
-@var{FRAME_FIND_SAVED_REGS} and @var{EXTRA_FRAME_INFO} are deprecated.
+@code{FRAME_FIND_SAVED_REGS} and @code{EXTRA_FRAME_INFO} are deprecated.
-@item FRAME_NUM_ARGS (fi)
+@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(frame)
-Given @var{frame}, return the pc saved there. That is, the return
+@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 GCC_COMPILED_FLAG_SYMBOL
-@item GCC2_COMPILED_FLAG_SYMBOL
-If defined, these are the names of the symbols that GDB 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 GDB_MULTI_ARCH
-If defined and non-zero, enables suport for multiple architectures
-within GDB.
+@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.
-The support can be enabled at two levels. At level one, only
+@item GCC_COMPILED_FLAG_SYMBOL
+@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 support 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
+a multi-arch definition of all architecture dependent macros will be
defined.
-@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
-@item GDB_TARGET_IS_SUN3
-@item GDB_TARGET_IS_SUN386
-Kludges that should go away.
+@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
+@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
-<setjmp.h> is needed to define it.
+the header file @file{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
+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
+@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
-Define this if the target has register windows.
-@item REGISTER_IN_WINDOW_P (regnum)
+@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
+@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 haste and we are
+feature-specific macros. It was introduced in a haste and we are
repenting at leisure.
-@item IEEE_FLOAT
-Define this if the target system uses IEEE-format floating point numbers.
+@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{$}.
-@item INIT_EXTRA_FRAME_INFO (fromleaf, frame)
+On HP-UX, certain system routines (millicode) have names beginning with
+@samp{$} or @samp{$$}. For example, @code{$$dyncall} is a millicode
+routine that handles inter-space procedure calls on PA-RISC.
+
+@item 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 (fromleaf, prev)
+@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 (lhs,rhs)
+@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 IN_SIGTRAMP (pc, name)
-Define this to return true if the given @var{pc} and/or @var{name}
-indicates that the current function is a sigtramp.
-
-@item SIGTRAMP_START (pc)
-@item SIGTRAMP_END (pc)
-Define these to be the start and end address of the sigtramp for the
+@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 pc name
+@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 pc name
+@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 IS_TRAPPED_INTERNALVAR (name)
+@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 GDB. Currently only used by the h8500. Note that this
+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
-Define this if GDB should determine the start and end addresses of the
+@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
+@findex NO_HIF_SUPPORT
(Specific to the a29k.)
-@item SOFTWARE_SINGLE_STEP_P
+@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.
+mechanism. The macro @code{SOFTWARE_SINGLE_STEP} must also be defined.
-@item SOFTWARE_SINGLE_STEP(signal,insert_breapoints_p)
-A function that inserts or removes (dependant on
+@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 @code{sparc-tdep.c} and @code{rs6000-tdep.c}
+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
+@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
+@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
+@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.
@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 PRINT_REGISTER_HOOK (regno)
+@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
+@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
+@findex PROCESS_LINENUMBER_HOOK
A hook defined for XCOFF reading.
@item PROLOGUE_FIRSTLINE_OVERLAP
+@findex PROLOGUE_FIRSTLINE_OVERLAP
(Only used in unsupported Convex configuration.)
@item PS_REGNUM
+@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.
+frame and in @samp{return_command} to remove a real stack frame.
-@item PUSH_ARGUMENTS (nargs, args, sp, struct_return, struct_addr)
+@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. Return the updated stack pointer value.
+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
-The total amount of space needed to store GDB's copy of the machine's
+@findex REGISTER_BYTES
+The total amount of space needed to store @value{GDBN}'s copy of the machine's
register state.
-@item REGISTER_NAME(i)
-Return the name of register @var{i} as a string. May return @var{NULL}
-or @var{NUL} to indicate that register @var{i} is not valid.
+@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
-Deprecated in favor of @var{REGISTER_NAME}.
+@findex REGISTER_NAMES
+Deprecated in favor of @code{REGISTER_NAME}.
-@item REG_STRUCT_HAS_ADDR (gcc_p, type)
+@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 (sp)
+@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 @var{SP} after both the dummy frame and space
+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
-Define this to convert sdb register numbers into GDB regnums. If not
+@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
+@findex SHIFT_INST_REGS
(Only used for m88k targets.)
-@item SKIP_PROLOGUE (pc)
+@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
-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 (pc)
+@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
+@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.
@code{TARGET_WRITE_SP} are not defined.
@item STAB_REG_TO_REGNUM
+@findex STAB_REG_TO_REGNUM
Define this to convert stab register numbers (as gotten from `r'
-declarations) into GDB regnums. If not defined, no conversion will be
+declarations) into @value{GDBN} regnums. If not defined, no conversion will be
done.
-@item STACK_ALIGN (addr)
+@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 (addr)
+@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, GDB will single-step over that instruction before resuming
+slot, @value{GDBN} will single-step over that instruction before resuming
normally. Currently only defined for the Mips.
-@item STORE_RETURN_VALUE (type, valbuf)
+@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
+@findex SUN_FIXED_LBRAC_BUG
(Used only for Sun-3 and Sun-4 targets.)
@item SYMBOL_RELOADING_DEFAULT
-The default value of the `symbol-reloading' variable. (Never defined in
+@findex SYMBOL_RELOADING_DEFAULT
+The default value of the ``symbol-reloading'' variable. (Never defined in
current sources.)
-@item TARGET_BYTE_ORDER_DEFAULT
-The ordering of bytes in the target. This must be either
-@code{BIG_ENDIAN} or @code{LITTLE_ENDIAN}. This macro replaces
-@var{TARGET_BYTE_ORDER} which is deprecated.
-
-@item TARGET_BYTE_ORDER_SELECTABLE_P
-Non-zero if the target has both @code{BIG_ENDIAN} and
-@code{LITTLE_ENDIAN} variants. This macro replaces
-@var{TARGET_BYTE_ORDER_SELECTABLE} which is deprecated.
-
@item TARGET_CHAR_BIT
+@findex TARGET_CHAR_BIT
Number of bits in a char; defaults to 8.
+@item TARGET_CHAR_SIGNED
+@findex TARGET_CHAR_SIGNED
+Non-zero if @code{char} is normally signed on this architecture; zero if
+it should be unsigned.
+
+The ISO C standard requires the compiler to treat @code{char} as
+equivalent to either @code{signed char} or @code{unsigned char}; any
+character in the standard execution set is supposed to be positive.
+Most compilers treat @code{char} as signed, but @code{char} is unsigned
+on the IBM S/390, RS6000, and PowerPC targets.
+
@item TARGET_COMPLEX_BIT
+@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
+@findex TARGET_DOUBLE_BIT
Number of bits in a double float; defaults to @code{8 * TARGET_CHAR_BIT}.
@item TARGET_DOUBLE_COMPLEX_BIT
+@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
+@findex TARGET_FLOAT_BIT
Number of bits in a float; defaults to @code{4 * TARGET_CHAR_BIT}.
@item TARGET_INT_BIT
+@findex TARGET_INT_BIT
Number of bits in an integer; defaults to @code{4 * TARGET_CHAR_BIT}.
@item TARGET_LONG_BIT
+@findex TARGET_LONG_BIT
Number of bits in a long integer; defaults to @code{4 * TARGET_CHAR_BIT}.
@item TARGET_LONG_DOUBLE_BIT
+@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
+@findex TARGET_LONG_LONG_BIT
Number of bits in a long long integer; defaults to @code{2 * TARGET_LONG_BIT}.
@item TARGET_PTR_BIT
+@findex TARGET_PTR_BIT
Number of bits in a pointer; defaults to @code{TARGET_INT_BIT}.
@item TARGET_SHORT_BIT
+@findex TARGET_SHORT_BIT
Number of bits in a short integer; defaults to @code{2 * TARGET_CHAR_BIT}.
@item TARGET_READ_PC
-@item TARGET_WRITE_PC (val, pid)
-@item TARGET_READ_SP
-@item TARGET_WRITE_SP
-@item TARGET_READ_FP
-@item TARGET_WRITE_FP
+@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
+@findex read_pc
+@findex write_pc
+@findex read_sp
+@findex write_sp
+@findex read_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. GDB will call the read
-and write register functions with the relevant @code{_REGNUM} argument.
+@code{read_sp}, @code{write_sp} and @code{read_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(pc,regp,offsetp)
+@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 @code{"pc"}. If 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 USE_STRUCT_CONVENTION (gcc_p, type)
+@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
for systems where GCC is known to use different calling convention than
other compilers.
-@item VARIABLES_INSIDE_BLOCK (desc, gcc_p)
+@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 GDB has noticed 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 (desc, gcc_p)
+@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.
-@table @code
-
+@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 table
+@end ftable
@section Adding a New Target
-The following files define a target to GDB:
+@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{}}. 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 and may go away in future versions of GDB.
+@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}.
-@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.
+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
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
+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.
-@item gdb/@var{arch}-tdep.c
-Similarly, there are often common subroutines that are shared by all
-target machines that use this particular architecture.
+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}
+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 GDB's abstract handling
-of target systems, and the nitty-gritty code that actually exercises
-control over a process or a serial port. GDB includes some 30-40
-different target vectors; however, each configuration of GDB includes
-only a few of them.
+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
@section Standard Protocol and Remote Stubs
-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}.
+@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 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.
+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
-trap_low:
+@code{trap_low}:
@enumerate
+@item
+%l1 and %l2 contain pc and npc respectively at the time of the trap;
-@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
+@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.
+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
+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,
+``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
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.
+They are simply done by deposit/examine operations from @value{GDBN}.
@section ROM Monitor Interface
@node Native Debugging
@chapter Native Debugging
+@cindex native debugging
-Several files control GDB's configuration for native support:
+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
+Specifies Makefile fragments needed by a @emph{native} configuration 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
define @samp{NAT_CFLAGS}, @samp{NAT_ADD_FILES}, @samp{NAT_CLIBS},
@samp{NAT_CDEPS}, etc.; see @file{Makefile.in}.
+@emph{Maintainer's note: The @file{.mh} suffix is because this file
+originally contained @file{Makefile} fragments for hosting @value{GDBN}
+on machine @var{xyz}. While the file is no longer used for this
+purpose, the @file{.mh} suffix remains. Perhaps someone will
+eventually rename these fragments so that they have a @file{.mn}
+suffix.}
+
@item gdb/config/@var{arch}/nm-@var{xyz}.h
-(@file{nm.h} is a link to this file, created by configure). Contains C
+(@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
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}-nat.c}, and put @code{@var{xyz}-nat.o}
+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.
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.
+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
@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 GDB
+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
@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
-When making GDB run native on a new operating system, to make it
+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 @samp{struct core}). Then
-modify @code{trad_unix_core_file_p()} to use these values to set up the
+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
standard way, which the section-reading routines in BFD know how to seek
around in.
-Then back in GDB, you need a matching routine called
-@code{fetch_core_registers()}. If you can use the generic one, it's 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 GDB's ``registers'' array.
+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
@section shared libraries
@section Native Conditionals
+@cindex native conditionals
-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}.
+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.
currently.]
@item FETCH_INFERIOR_REGISTERS
+@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{@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, /proc support uses this
+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
+@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
-<setjmp.h> is needed to define it.
+@file{setjmp.h} is needed to define it.
-This macro determines the target PC address that longjmp() will jump to,
+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
-CORE_ADDR * as argument, and stores the target PC value through this
+@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. GDB
+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
-Define this to cause GDB to determine the address of @code{u} at
+@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
-Define this to cause GDB to determine the address of @code{u} at
+@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}
+@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 GDB must step over 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
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
+@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
+@findex REGISTER_U_ADDR
Defines the offset of the registers in the ``u area''.
@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 (filename, from_tty, targ)
+@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 GDB's symbol table.
+@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
-When starting an inferior, GDB normally expects to trap twice; once when
+@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 GDB's internal representation and the
-/proc representation, are compiled.
+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
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.
+that @code{u.u_ar0} @emph{is} the location of the registers.
@item CLEAR_SOLIB
-objfiles.c
+@findex CLEAR_SOLIB
+See @file{objfiles.c}.
@item DEBUG_PTRACE
-Define this to debug ptrace calls.
-
+@findex DEBUG_PTRACE
+Define this to debug @code{ptrace} calls.
@end table
@chapter Support Libraries
@section BFD
+@cindex BFD library
-BFD provides support for GDB in several ways:
+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). GDB simply calls BFD to
-read or write section X at byte offset Y for length Z.
+(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 matches (i.e.@: could be a core dump of) a particular executable
file.
@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
+@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 GDB uses BFD's cached information to find the symbols,
+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 GDB's disassembler. (It's a separate
+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 libiberty
@section gnu-regex
+@cindex regular expressions library
Regex conditionals.
@table @code
-
@item C_ALLOCA
@item NFAILURES
@item Sword
@item sparc
-
@end table
@section include
@chapter Coding
This chapter covers topics that are lower-level than the major
-algorithms of GDB.
+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.
+later.
-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.
+When your code does something (e.g., @code{xmalloc} some memory, or
+@code{open} a file) that needs to be undone later (e.g., @code{xfree}
+the memory or @code{close} the file), it can make a cleanup. The
+cleanup will be done at some future point: when the command is finished
+and control returns to the top level; when an error occurs and the stack
+is unwound; or when your code decides it's time to explicitly perform
+cleanups. Alternatively you can elect to discard the cleanups you
+created.
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}.
+handle that can later be passed to @code{do_cleanups} or
+@code{discard_cleanups}. Unless you are going to call
+@code{do_cleanups} or @code{discard_cleanups}, 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
+Do all cleanups added to the chain since the corresponding
+@code{make_cleanup} call was made.
+@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
+Cleanups are implemented as a chain. The handle returned by
+@code{make_cleanups} includes the cleanup passed to the call and any
+later cleanups appended to the chain (but not yet discarded or
+performed). E.g.:
+
+@smallexample
+make_cleanup (a, 0);
+@{
+ struct cleanup *old = make_cleanup (b, 0);
+ make_cleanup (c, 0)
+ ...
+ do_cleanups (old);
+@}
+@end smallexample
+
+@noindent
+will call @code{c()} and @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
+
+Your function should explicitly do or discard the cleanups it creates.
+Failing to do this leads to non-deterministic behavior since the caller
+will arbitrarily do or discard your functions cleanups. This need leads
+to two common cleanup styles.
+
+The first style is try/finally. Before it exits, your code-block calls
+@code{do_cleanups} with the old cleanup chain and thus ensures that your
+code-block's cleanups are always performed. For instance, the following
+code-segment avoids a memory leak problem (even when @code{error} is
+called and a forced stack unwind occurs) by ensuring that the
+@code{xfree} will always be called:
+
+@smallexample
+struct cleanup *old = make_cleanup (null_cleanup, 0);
+data = xmalloc (sizeof blah);
+make_cleanup (xfree, data);
+... blah blah ...
+do_cleanups (old);
+@end smallexample
+
+The second style is try/except. Before it exits, your code-block calls
+@code{discard_cleanups} with the old cleanup chain and thus ensures that
+any created cleanups are not performed. For instance, the following
+code segment, ensures that the file will be closed but only if there is
+an error:
+
+@smallexample
+FILE *file = fopen ("afile", "r");
+struct cleanup *old = make_cleanup (close_file, file);
+... blah blah ...
+discard_cleanups (old);
+return file;
+@end smallexample
+
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
@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
@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
+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
+to unfiltered (@code{printf}) output. Symbol reading routines that
print warnings are a good example.
-@section GDB Coding Standards
+@section @value{GDBN} Coding Standards
+@cindex coding standards
-GDB follows the GNU coding standards, as described in
+@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. GDB takes a strict interpretation of the
-standard; in general, when the GNU standard recommends a practice but
-does not require it, GDB requires it.
+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
-GDB follows an additional set of coding standards specific to GDB,
-as described in the following sections.
+@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}.
-You can configure with @samp{--enable-build-warnings} to get GCC to
-check on a number of these rules. GDB sources ought not to engender any
-complaints, unless they are caused by bogus host systems. (The exact
-set of enabled warnings is currently @samp{-Wall -Wpointer-arith
--Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations}.
+@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.
-Note that while in a definition, the function's name must be in column
-zero; in a function declaration, the name must be on the same line as
-the return type.
+A function declaration should not have its name in column zero. A
+function definition should have its name in column zero.
+
+@smallexample
+/* Declaration */
+static void foo (void);
+/* Definition */
+void
+foo (void)
+@{
+@}
+@end smallexample
+
+@emph{Pragmatics: This simplifies scripting. Function definitions can
+be found using @samp{^function-name}.}
-In addition, 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.
+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 diff and
-patch.
+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:
+
+@smallexample
+void *foo;
+@end smallexample
+
+@noindent
+and not:
+
+@smallexample
+void * foo;
+void* foo;
+@end smallexample
@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 `/*'- or
-'*/'-only lines, and no leading `*':
+Block comments must appear in the following form, with no @code{/*}- or
+@code{*/}-only lines, and no leading @code{*}:
-@example @code
+@smallexample
/* 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 GDB should read more commands. */
-@end example
+ stopped and @value{GDBN} should read more commands. */
+@end smallexample
(Note that this format is encouraged by Emacs; tabbing for a multi-line
-comment works correctly, and M-Q fills the block consistently.)
+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.
@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 GDB that might be affected by the overhead of a function call, mainly
-in symbol reading. Most of GDB's performance is limited by the target
-interface (whether serial line or system call).
+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 to @emph{declare} functions but never to
-@emph{define} them. Prototypes for GDB functions must include both the
+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.
-For the sake of compatibility with pre-ANSI compilers, define prototypes
-with the @code{PARAMS} macro:
+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 situations where @value{GDBN} has detected, at
+run time, a corrupt or erroneous situation.
+
+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.}
-@example @code
-extern int memory_remove_breakpoint PARAMS ((CORE_ADDR addr,
- char *contents_cache));
-@end example
+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}).
-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:
+For other files @samp{-} is used as the separator.
-@example @code
-extern void noprocess PARAMS ((void));
-@end example
-The @code{PARAMS} macro expands to its argument in ANSI C, or to a
-simple @code{()} in traditional C.
+@subsection Include Files
-All external functions should have a @code{PARAMS} 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.
+All @file{.c} files should include @file{defs.h} first.
-All static functions must be declared in a block near the top of the
-source file.
+All @file{.c} files should explicitly include the headers for any
+declarations they refer to. They should not rely on files being
+included indirectly.
-@subsection Clean Design
+With the exception of the global definitions supplied by @file{defs.h},
+a header file should explicitly 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:
+
+@smallexample
+#ifndef INCLUDE_FILE_NAME_H
+#define INCLUDE_FILE_NAME_H
+header body
+#endif
+@end smallexample
+
+
+@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 GDB because long
+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 GDB, or one of
-the swap routines defined in @file{bfd.h}, such as @code{bfd_get_32}.
+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
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
with regard to this feature.
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:
-
-@example
-#ifdef WRANGLE_SIGNALS
- WRANGLE_SIGNALS (signo);
-#endif
-@end example
-
-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.
+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:
-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
+@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
-@example
-#ifndef SPECIAL_FOO_HANDLING
-#define SPECIAL_FOO_HANDLING(pc, sp) (0)
-#endif
-@end example
-
-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
+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.
-`target_has_stack'), or a function is called through a pointer in the
+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
+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.
+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.
-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.
+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}.
-Don't put debugging printfs in the code.
@node Porting GDB
-@chapter Porting GDB
+@chapter Porting @value{GDBN}
+@cindex porting to new machines
-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{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:
+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
@code{@var{arch}-@var{xvend}-@var{xos}}. You can test your changes by
running
-@example
+@smallexample
./config.sub @var{xyz}
-@end example
+@end smallexample
+
@noindent
and
-@example
+
+@smallexample
./config.sub @code{@var{arch}-@var{xvend}-@var{xos}}
-@end example
+@end smallexample
+
@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.
-To configure GDB itself, edit @file{gdb/configure.host} to recognize
+@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}).
-Finally, you'll need to specify and define GDB's host-, native-, and
+@emph{Maintainer's note: Work in progress. The file
+@file{gdb/configure.host} originally needed to be modified when either a
+new native target or a new host machine was being added to @value{GDBN}.
+Recent changes have removed this requirement. The file now only needs
+to be modified when adding a new native configuration. This will likely
+changed again in the future.}
+
+@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 GDB for Release
+@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
+
+@smallexample
make -f Makefile.in gdb.tar.gz
-@end example
+@end smallexample
+@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}
+
+@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.).
@code{makeinfo} will split the document into one overall file and five
or so included files.
+
+@node Releasing GDB
+
+@chapter Releasing @value{GDBN}
+@cindex making a new release of gdb
+
+@section Versions and Branches
+
+@subsection Version Identifiers
+
+@value{GDBN}'s version is determined by the file @file{gdb/version.in}.
+
+@value{GDBN}'s mainline uses ISO dates to differentiate between
+versions. The CVS repository uses @var{YYYY}-@var{MM}-@var{DD}-cvs
+while the corresponding snapshot uses @var{YYYYMMDD}.
+
+@value{GDBN}'s release branch uses a slightly more complicated scheme.
+When the branch is first cut, the mainline version identifier is
+prefixed with the @var{major}.@var{minor} from of the previous release
+series but with .90 appended. As draft releases are drawn from the
+branch, the minor minor number (.90) is incremented. Once the first
+release (@var{M}.@var{N}) has been made, the version prefix is updated
+to @var{M}.@var{N}.0.90 (dot zero, dot ninety). Follow on releases have
+an incremented minor minor version number (.0).
+
+Using 5.1 (previous) and 5.2 (current), the example below illustrates a
+typical sequence of version identifiers:
+
+@table @asis
+@item 5.1.1
+final release from previous branch
+@item 2002-03-03-cvs
+main-line the day the branch is cut
+@item 5.1.90-2002-03-03-cvs
+corresponding branch version
+@item 5.1.91
+first draft release candidate
+@item 5.1.91-2002-03-17-cvs
+updated branch version
+@item 5.1.92
+second draft release candidate
+@item 5.1.92-2002-03-31-cvs
+updated branch version
+@item 5.1.93
+final release candidate (see below)
+@item 5.2
+official release
+@item 5.2.0.90-2002-04-07-cvs
+updated CVS branch version
+@item 5.2.1
+second official release
+@end table
+
+Notes:
+
+@itemize @bullet
+@item
+Minor minor minor draft release candidates such as 5.2.0.91 have been
+omitted from the example. Such release candidates are, typically, never
+made.
+@item
+For 5.1.93 the bziped tar ball @file{gdb-5.1.93.tar.bz2} is just the
+official @file{gdb-5.2.tar} renamed and compressed.
+@end itemize
+
+To avoid version conflicts, vendors are expected to modify the file
+@file{gdb/version.in} to include a vendor unique alphabetic identifier
+(an official @value{GDBN} release never uses alphabetic characters in
+its version identifer).
+
+Since @value{GDBN} does not make minor minor minor releases (e.g.,
+5.1.0.1) the conflict between that and a minor minor draft release
+identifier (e.g., 5.1.0.90) is avoided.
+
+
+@subsection Branches
+
+@value{GDBN} draws a release series (5.2, 5.2.1, @dots{}) from a single
+release branch (gdb_5_2-branch). Since minor minor minor releases
+(5.1.0.1) are not made, the need to branch the release branch is avoided
+(it also turns out that the effort required for such a a branch and
+release is significantly greater than the effort needed to create a new
+release from the head of the release branch).
+
+Releases 5.0 and 5.1 used branch and release tags of the form:
+
+@smallexample
+gdb_N_M-YYYY-MM-DD-branchpoint
+gdb_N_M-YYYY-MM-DD-branch
+gdb_M_N-YYYY-MM-DD-release
+@end smallexample
+
+Release 5.2 is trialing the branch and release tags:
+
+@smallexample
+gdb_N_M-YYYY-MM-DD-branchpoint
+gdb_N_M-branch
+gdb_M_N-YYYY-MM-DD-release
+@end smallexample
+
+@emph{Pragmatics: The branchpoint and release tags need to identify when
+a branch and release are made. The branch tag, denoting the head of the
+branch, does not have this criteria.}
+
+
+@section Branch Commit Policy
+
+The branch commit policy is pretty slack. @value{GDBN} releases 5.0,
+5.1 and 5.2 all used the below:
+
+@itemize @bullet
+@item
+The @file{gdb/MAINTAINERS} file still holds.
+@item
+Don't fix something on the branch unless/until it is also fixed in the
+trunk. If this isn't possible, mentioning it in the @file{gdb/PROBLEMS}
+file is better than committing a hack.
+@item
+When considering a patch for the branch, suggested criteria include:
+Does it fix a build? Does it fix the sequence @kbd{break main; run}
+when debugging a static binary?
+@item
+The further a change is from the core of @value{GDBN}, the less likely
+the change will worry anyone (e.g., target specific code).
+@item
+Only post a proposal to change the core of @value{GDBN} after you've
+sent individual bribes to all the people listed in the
+@file{MAINTAINERS} file @t{;-)}
+@end itemize
+
+@emph{Pragmatics: Provided updates are restricted to non-core
+functionality there is little chance that a broken change will be fatal.
+This means that changes such as adding a new architectures or (within
+reason) support for a new host are considered acceptable.}
+
+
+@section Obsolete any code
+
+Before anything else, poke the other developers (and around the source
+code) to see if there is anything that can be removed from @value{GDBN}
+(an old target, an unused file).
+
+Obsolete code is identified by adding an @code{OBSOLETE} prefix to every
+line. Doing this means that it is easy to identify obsolete code when
+grepping through the sources.
+
+The process has a number of steps and is intentionally slow --- this is
+to mainly ensure that people have had a reasonable chance to respond.
+Remember, everything on the internet takes a week.
+
+@itemize @bullet
+@item
+announce the change on @email{gdb@@sources.redhat.com, GDB mailing list}
+@item
+wait a week or so
+@item
+announce the change on @email{gdb-announce@@sources.redhat.com, GDB
+Announcement mailing list}
+@item
+wait a week or so
+@item
+go through and edit all relevant files and lines (e.g., in
+@file{configure.tgt}) so that they are prefixed with the word
+@code{OBSOLETE}.
+@end itemize
+
+@emph{Maintainer note: Removing old code, while regrettable, is a good
+thing. Firstly it helps the developers by removing code that is either
+no longer relevant or simply wrong. Secondly since it removes any
+history associated with the file (effectively clearing the slate) the
+developer has a much freer hand when it comes to fixing broken files.}
+
+
+@section Before the Branch
+
+The most important objective at this stage is to find and fix simple
+changes that become a pain to track once the branch is created. For
+instance, configuration problems that stop @value{GDBN} from even
+building. If you can't get the problem fixed, document it in the
+@file{gdb/PROBLEMS} file.
+
+@subheading Prompt for @file{gdb/NEWS}
+
+People always forget. Send a post reminding them but also if you know
+something interesting happened add it yourself. The @code{schedule}
+script will mention this in its e-mail.
+
+@subheading Review @file{gdb/README}
+
+Grab one of the nightly snapshots and then walk through the
+@file{gdb/README} looking for anything that can be improved. The
+@code{schedule} script will mention this in its e-mail.
+
+@subheading Refresh any imported files.
+
+A number of files are taken from external repositories. They include:
+
+@itemize @bullet
+@item
+@file{texinfo/texinfo.tex}
+@item
+@file{config.guess} et.@: al.@: (see the top-level @file{MAINTAINERS}
+file)
+@item
+@file{etc/standards.texi}, @file{etc/make-stds.texi}
+@end itemize
+
+@subheading Check the ARI
+
+@uref{http://sources.redhat.com/gdb/ari,,A.R.I.} is an @code{awk} script
+(Awk Regression Index ;-) that checks for a number of errors and coding
+conventions. The checks include things like using @code{malloc} instead
+of @code{xmalloc} and file naming problems. There shouldn't be any
+regressions.
+
+@subsection Review the bug data base
+
+Close anything obviously fixed.
+
+@subsection Check all cross targets build
+
+The targets are listed in @file{gdb/MAINTAINERS}.
+
+
+@section Cut the branch
+
+@subheading The dirty work
+
+I think something like the below was used:
+
+@smallexample
+$ d=`date -u +%Y-%m-%d`
+$ echo $d
+2002-01-24
+$ cvs -f -d /cvs/src rtag -D $d-gmt \
+gdb_5_1-$d-branchpoint insight+dejagnu
+$ cvs -f -d /cvs/src rtag -b -r gdb_V_V-$d-branchpoint \
+gdb_5_1-$d-branch insight+dejagnu
+$
+@end smallexample
+
+@itemize @bullet
+@item
+the @kbd{-D YYYY-MM-DD-gmt} forces the branch to an exact date/time.
+@item
+the trunk is first tagged so that the branch point can easily be found
+@item
+Insight (which includes GDB) and dejagnu are tagged at the same time
+@end itemize
+
+@subheading Post the branch info
+
+@subheading Update the web and news pages
+
+@subheading Tweak cron to track the new branch
+
+@section Stabilize the branch
+
+Something goes here.
+
+@section Create a Release
+
+This procedure can be followed when creating beta and final final
+releases. With a beta many of the steps can be skipped.
+
+@subheading Establish a few defaults.
+
+@smallexample
+$ b=gdb_5_1-2001-07-29-branch
+$ v=5.1.1
+$ t=/sourceware/snapshot-tmp/gdbadmin-tmp
+$ echo $t/$b/$v
+$ mkdir -p $t/$b/$v
+$ cd $t/$b/$v
+$ pwd
+/sourceware/snapshot-tmp/gdbadmin-tmp/gdb_5_1-2001-07-29-branch/5.1.1
+$ which autoconf
+/home/gdbadmin/bin/autoconf
+$
+@end smallexample
+
+NB: Check the autoconf version carefully. You want to be using the
+version taken from the binutils snapshot directory. It is most likely
+that your system's installed version (@file{/usr/bin}?) is probably
+correct.
+
+@subheading Check out the relevant modules:
+
+@smallexample
+$ for m in gdb insight dejagnu
+do
+( mkdir -p $m && cd $m && cvs -q -f -d /cvs/src co -P -r $b $m )
+done
+$
+@end smallexample
+
+NB: The reading of @file{.cvsrc} is disabled (@file{-f}) so that there
+isn't any confusion between what is written here and what your local CVS
+really does.
+
+@subheading Update relevant files.
+
+@subsubheading @file{gdb/NEWS}
+
+Major releases get their comments added as part of the mainline. Minor
+releases should probably mention any significant bugs that were fixed.
+
+Don't forget to update the ChangeLog.
+
+@smallexample
+$ emacs gdb/src/gdb/NEWS
+...
+c-x 4 a
+...
+c-x c-s c-x c-c
+$ cp gdb/src/gdb/NEWS insight/src/gdb/NEWS
+$ cp gdb/src/gdb/ChangeLog insight/src/gdb/ChangeLog
+@end smallexample
+
+@subsubheading @file{gdb/README}
+
+You'll need to update: the version, the update date, and who did it.
+
+@smallexample
+$ emacs gdb/src/gdb/README
+...
+c-x 4 a
+...
+c-x c-s c-x c-c
+$ cp gdb/src/gdb/README insight/src/gdb/README
+$ cp gdb/src/gdb/ChangeLog insight/src/gdb/ChangeLog
+@end smallexample
+
+@emph{Maintainer note: Hopefully the README file was reviewed before the
+initial branch was cut so just a simple substitute is needed to get it
+updated.}
+
+@emph{Maintainer note: Other projects generate @file{README} and
+@file{INSTALL} from the core documentation. This might be worth
+pursuing.}
+
+@subsubheading @file{gdb/version.in}
+
+@smallexample
+$ echo $v > gdb/src/gdb/version.in
+$ emacs gdb/src/gdb/version.in
+...
+c-x 4 a
+...
+c-x c-s c-x c-c
+$ cp gdb/src/gdb/version.in insight/src/gdb/version.in
+$ cp gdb/src/gdb/ChangeLog insight/src/gdb/ChangeLog
+@end smallexample
+
+@subsubheading @file{dejagnu/src/dejagnu/configure.in}
+
+Dejagnu is more complicated. The version number is a parameter to
+@var{AM_INIT_AUTOMAKE}. Tweak it to read something like
+@var{gdb-5.1.1}.
+
+Re-generate configure.
+
+Add a ChangeLog.
+
+@subheading Do the dirty work
+
+This is identical to the process used when creating the daily snapshot.
+
+@smallexample
+$ for m in gdb insight dejagnu
+do
+( cd $m/src && gmake -f Makefile.in $m.tar.bz2 )
+done
+@end smallexample
+
+@subheading Check the source files
+
+You're looking for files that have mysteriously disappeared as the
+@kbd{distclean} has the habit of deleting files it shouldn't. Watch out
+for the @file{version.in} update @kbd{cronjob}.
+
+@smallexample
+$ ( cd gdb/src && cvs -f -q -n update )
+M djunpack.bat
+? proto-toplev
+? gdb-5.1.1.tar.bz2
+M gdb/ChangeLog
+M gdb/NEWS
+M gdb/README
+M gdb/version.in
+? gdb/p-exp.tab.c
+? gdb/doc/gdb.info-11
+? gdb/doc/gdb.info-12
+? gdb/doc/gdb.info-13
+? gdb/doc/gdb.info-14
+? gdb/doc/gdb.info-15
+? gdb/doc/gdbint.info-4
+? gdb/doc/gdbint.info-5
+$
+@end smallexample
+
+@emph{Don't worry about the @file{gdb.info-??} or
+@file{gdb/p-exp.tab.c}. They were generated (and yes @file{gdb.info-1}
+was also generated only something strange with CVS means that they
+didn't get supressed). Fixing it would be nice though.}
+
+@subheading Re-pack the release with @code{gzip}
+
+@smallexample
+$ cp */*/*.bz2 .
+$ bunzip2 -k -v *.bz2
+$ gzip -9 -v *.tar
+@end smallexample
+
+NB: A pipe such as @kbd{bunzip2 < xxx.bz2 | gzip -9 > xxx.gz} shouldn't
+be used since, in that mode, gzip doesn't know the file name information
+and consequently can't include it. This is also why the release process
+runs @code{tar} and @code{bzip2} as separate passes.
+
+@emph{Maintainer note: The release process could be changed to create
+@file{.tar} rather than @file{.tar.bz2} files.}
+
+@section Check the release
+
+Grab the @file{gdb.tar.bz2}, copy it to your local machine and then try
+a simple build using it.
+
+If this is a pre-release just copy the @file{.bz2} files to the snapshot
+directory and skip the remaining steps.
+
+If it is a final release, also make it available under a bogus name so
+that others can download and check it.
+
+@emph{Maintainer note: This adds an extra day to the release process but
+is very much worth it. Other developers are given the opportunity to
+check that things like your @file{NEWS} entries are correct or that
+other changes actually work.}
+
+@section Release the tar ball
+
+This is where, unfortunately, the notes just get vague.
+
+@subheading Install on sware
+
+@smallexample
+$ cp *.bz2 *.gz ~ftp/pub/gdb/releases
+@end smallexample
+
+@subheading Create and update the web pages.
+
+Try the following:
+
+@itemize @bullet
+@item
+create the directory @file{htdocs/@var{version}} (e.g., @file{htdocs/5.1.1}
+@item
+copy @file{index.html} and @file{ANNOUNCE} from the previous release
+into the @file{htdocs/@var{version}} directory and edit for content.
+Things like the MD5 sums, @kbd{ls -l} output, the version number and so
+on will need updating. Add NEWS entries to the @file{ANNOUNCE}. This
+ensures that the previous announcement is kept somewhere handy.
+@item
+copy the @file{NEWS} from the distro into the
+@file{htdocs/@var{version}} directory, trim down to just the most recent
+news items
+@item
+Add a short (identical) announcement to both @file{htdocs/index.html}
+and @file{htdocs/news/index.html}
+@item
+edit the script @file{htdocs/index.sh} to link in the new release
+number. Run it across all @file{index.html} files vis @kbd{./index.sh
+index.html */index.html}.
+@item
+grep the @file{htdocs} tree for references to the previous release
+version (@file{htdocs/download/index.html})
+@end itemize
+
+@emph{Maintainer note: This step is too fragile --- it is too easy to
+mis one of the entries and forget to update it.}
+
+@subheading Generate online docs
+
+You need to find the magic command that is used to generate the online
+docs from the @file{.tar.bz2}. The best way is to look in the output
+from one of the nightly cronjobs and then just edit accordingly.
+Something like:
+
+@smallexample
+$ ~/ss/update-web-docs \
+ ~ftp/pub/gdb/releases/gdb-5.1.1.tar.bz2 \
+ $PWD/www \
+ /www/sourceware/htdocs/gdb/5.1.1/onlinedocs \
+ gdb
+@end smallexample
+
+@subheading Something about @file{ANNOUNCEMENT}
+
+Send the @file{ANNOUNCEMENT} file you created above to:
+
+@itemize @bullet
+@item
+@email{gdb-announce@@sources.redhat.com, GDB Announcement mailing list}
+@item
+The gnu announce list (but delay it a day or so to let things get out).
+@end itemize
+
+@subheading Install it on GNU
+
+At the time of writing, the GNU machine was @kbd{gnudist.gnu.org} in
+@file{~ftp/gnu/gdb} (I think, I'm still waiting for it to copy into my
+home directory).
+
+@section Cleanup
+
+@subheading Commit outstanding changes
+
+In particular you'll need to commit the changes to:
+
+@itemize @bullet
+@item
+@file{gdb/ChangeLog}
+@item
+@file{gdb/version.in}
+@item
+@file{gdb/NEWS}
+@item
+@file{gdb/README}
+@end itemize
+
+@subheading Tag the release
+
+Something like:
+
+@smallexample
+$ d=`date -u +%Y-%m-%d`
+$ echo $d
+2002-01-24
+$ ( cd insight/src/gdb && cvs -f -q update )
+$ ( cd insight/src && cvs -f -q tag gdb_5_1_1-$d-release )
+@end smallexample
+
+Insight is used since that contains more of the release than GDB (yes
+dejagnu doesn't get tagged but I think we can live with that.).
+
+@subheading Restart @file{gdb/version.in}
+
+If @file{gdb/version.in} does not contain an ISO date such as
+@kbd{2002-01-24} then the daily @code{cronjob} won't update it. Having
+committed all the release changes it can be set to
+@file{5.1.0_0000-00-00-cvs} which will restart things (yes the @kbd{_}
+is important - it affects the snapshot process).
+
+Don't forget the @file{ChangeLog}.
+
+@subheading Merge into trunk
+
+The files committed to the branch may also need changes merged into the
+trunk.
+
+@section Post release
+
+Remove any @code{OBSOLETE} code.
+
@node Testsuite
@chapter Testsuite
+@cindex test suite
-The testsuite is an important component of the GDB 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 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 GDB testsuite uses the DejaGNU testing framework. DejaGNU is built
-using tcl and expect. The tests themselves are calls to various tcl
-procs; the framework runs all the procs and summarizes the passes and
-fails.
+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
-To run the testsuite, simply go to the GDB object directory (or to the
+@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
+
+@smallexample
=== gdb Summary ===
# of expected passes 6016
# of expected failures 183
# of unresolved testcases 3
# of untested testcases 5
-@end example
+@end smallexample
+
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 GDB 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 GDB. 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 GDB, 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 GDB, please consider adding tests for it
-as well; this way future GDB 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.
+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 GDB will run. The file
+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 GDB tests, while the directory @file{testsuite/config} contains
+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}.
execution environment, this organization is simply for convenience and
intelligibility.
-@table @code
-
+@table @file
@item gdb.base
-
This is the base testsuite. The tests in it should apply to all
-configurations of GDB (but generic native-only tests may live here).
+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++ (ifdefs are allowed if necessary, for instance
+ANSI/ISO, and C++ (@code{#ifdef}s are allowed if necessary, for instance
for prototypes).
@item gdb.@var{lang}
-
-Language-specific tests for all languages besides C. Examples are
+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 gdb.gcc, for tests of GDB's handling of GCC extensions.
+imagine a @file{gdb.gcc}, for tests of @value{GDBN}'s handling of GCC
+extensions.
@item gdb.@var{subsystem}
-
-Tests that exercise a specific GDB subsystem in more depth. For
+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 GDB tests are already quite comprehensive; you
+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
calls @code{gdb_test} multiple times.
Only use @code{send_gdb} and @code{gdb_expect} when absolutely
-necessary, such as when GDB has several valid responses to a command.
+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 GDB is used to debug programs written in many different
+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 GDB bugs involving the display of source lines would
+instance, some @value{GDBN} bugs involving the display of source lines would
never manifest themselves if the programs used GNU coding style
uniformly.
appear anywhere else in the directory.
@menu
-* Getting Started:: Getting started working on GDB
-* Debugging GDB:: Debugging GDB with itself
+* Getting Started:: Getting started working on @value{GDBN}
+* Debugging GDB:: Debugging @value{GDBN} with itself
@end menu
@node Getting Started,,, Hints
@section Getting Started
-GDB is a large and complicated program, and if you first starting to
+@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 GDB Internals manual, has information which applies
-generally to many parts of GDB.
+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 GDB; feel
+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.
@c Conditionals}, @pxref{Native Conditionals}, and @pxref{Obsolete
@c Conditionals})
-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.
+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 GDB, use
+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 GDB to start with, you can find more
+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
else, just try to understand generally what the code being called does,
rather than worrying about all its details.
-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}.
-
+@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
-GDB''---if we had some magic secret we would put it in this manual.
+@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 GDB with itself
+@section Debugging @value{GDBN} with itself
+@cindex debugging @value{GDBN}
-If GDB is limping on your machine, this is the preferred way to get it
+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 @code{@w{./gdb
+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 @code{@w{./gdb ./gdb2}}.
+@file{gdb2} and then type @kbd{@w{./gdb ./gdb2}}.
-When you run GDB in the GDB source directory, it will read a
+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 GDB being debugged by gdb, will pop you back up to the top level
+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
routines for your local machine where they will be accessed first by
@kbd{M-.}
-Also, make sure that you've either compiled GDB with your local cc, or
+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
-GDB users. In general we like to get well designed enhancements.
+@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 GDB maintainers will only install ``cleanly designed'' patches.
-This manual summarizes what we believe to be clean design for GDB.
+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 GDB, but GAS, Emacs, GCC, etc) can be
+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
-bureacracy and filed with the FSF. We can't start merging changes until
+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 "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.texinfo or gdb/doc/gdbint.texinfo). If there are a lot of
-changes for a single feature, they can be split down into multiple
-messages.
+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 ChangeLog, we have to write one. If you leave
-out the doc, we have to puzzle out what needs documenting. Etc.
+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
permits, which, since the maintainers have many demands to meet, may not
be for quite some time.
-Please send patches directly to the GDB maintainers at
-@code{gdb-patches@@sourceware.cygnus.com}.
+Please send patches directly to
+@email{gdb-patches@@sources.redhat.com, the @value{GDBN} maintainers}.
@section Obsolete Conditionals
+@cindex obsolete code
-Fragments of old code in GDB sometimes reference or set the following
+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
+@end table
-@item REG_STACK_SEGMENT
-exec.c
+@include fdl.texi
-@end table
+@node Index
+@unnumbered Index
+@printindex cp
-@contents
@bye
projects / deliverable / binutils-gdb.git / blobdiff