\input texinfo
@setfilename gdbint.info
-
+@include gdb-cfg.texi
@ifinfo
@format
START-INFO-DIR-ENTRY
@end ifinfo
@ifinfo
-This file documents the internals of the GNU debugger GDB.
+This file documents the internals of the GNU debugger @value{GDBN}.
Copyright 1990-1999 Free Software Foundation, Inc.
Contributed by Cygnus Solutions. Written by John Gilmore.
@end ifinfo
@setchapternewpage off
-@settitle GDB Internals
+@settitle @value{GDBN} Internals
@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 titlepage
+@c TeX can handle the contents at the start but makeinfo 3.12 can not
+@iftex
+@contents
+@end iftex
+
@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::
* Support Libraries::
* Coding::
* Porting GDB::
+* Testsuite::
* Hints::
@end menu
@chapter Requirements
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
+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
+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
+@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
+@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
+@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
+@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
+@value{GDBN} consists of three major subsystems: user interface, symbol handling
(the ``symbol side''), and target system handling (the ``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
+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
+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.
+@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.
@chapter Algorithms
-GDB uses a number of debugging-specific algorithms. They are often not
+@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
+A frame is a construct that @value{GDBN} uses to keep track of calling and called
functions.
@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
+machine-independent part of @value{GDBN}, except that it is used when setting up
a new frame from scratch, as follows:
@example
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
+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.
features with some chips. Typically these work by having dedicated
register into which the breakpoint address may be stored. If the PC
ever matches a value in a breakpoint registers, the CPU raises an
-exception and reports it to GDB. Another possibility is when an
+exception and reports it to @value{GDBN}. Another possibility is when an
emulator is in use; many emulators include circuitry that watches the
address lines coming out from the processor, and force it to stop if the
address matches a breakpoint's address. A third possibility is that the
target already has the ability to do breakpoints somehow; for instance,
a ROM monitor may do its own software breakpoints. So although these
-are not literally ``hardware breakpoints'', from GDB's point of view
-they work the same; GDB need not do nothing more than set the breakpoint
+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
+limited in number; when the user asks for more, @value{GDBN} 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
+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
@section Longjmp Support
-GDB has support for figuring out that the target is doing a
+@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.
@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
+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.
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.
+
+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 comamnd 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 Console Printing
@section libgdb
@code{libgdb} was an abortive project of years ago. The theory was to
-provide an API to GDB's functionality.
+provide an API to @value{GDBN}'s functionality.
@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
+@value{GDBN} reads symbols from ``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 @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
+header. @code{find_sym_fns} then uses this identification to locate a
set of symbol-reading functions.
-Symbol reading modules identify themselves to GDB by calling
+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,
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
+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
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)
@section Partial Symbol Tables
-GDB has three types of symbol tables.
+@value{GDBN} has three types of symbol tables.
@itemize @bullet
file's debugging information. Small amounts of information are
extracted -- enough to identify which parts of the symbol table will
need to be re-read and fully digested later, when the user needs the
-information. The speed of this pass causes GDB to start up very
+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.
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,
+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.
Fundamental Types (e.g., FT_VOID, FT_BOOLEAN).
-These are the fundamental types that GDB uses internally. Fundamental
+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 gdb knows about for all the languages that @value{GDBN} knows about.
Type Codes (e.g., TYPE_CODE_PTR, TYPE_CODE_ARRAY).
-Each time GDB builds an internal type, it marks it with one of these
+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 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
Builtin Types (e.g., builtin_type_void, 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
+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 builtin_type_int initialized in gdbtypes.c is
basically the same as a TYPE_CODE_INT type that is initialized in
Windows 95 and NT use the PE (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
@subsection Other File Formats
-Other file formats that have been supported by GDB include Netware
+Other file formats that have been supported by @value{GDBN} include Netware
Loadable Modules (@file{nlmread.c}.
@section Debugging File Formats
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),
there is probably little to be done.
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/libxyz.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
+@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
+@value{GDBN} 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.
-@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
+To add other languages to @value{GDBN}'s expression parser, follow the following
steps:
@table @emph
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
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.
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.
@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
+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
+See the file @file{configure.in} for how @value{GDBN} is configured for different
languages.
@item Edit @file{Makefile.in}
@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
+Most of @value{GDBN}'s host configuration support happens via autoconf. It
+should be rare to need new host-specific definitions. @value{GDBN} still uses
the host-specific definitions and files listed below, but these mostly
exist for historical reasons, and should eventually disappear.
-Several files control GDB's configuration for host systems:
+Several files control @value{GDBN}'s configuration for host systems:
@table @file
@section Host Conditionals
-When GDB is configured and compiled, various macros are defined or left
+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
@table @code
-@item GDBINIT_FILENAME
-The default name of GDB's initialization file (normally @file{.gdbinit}).
+@item @value{GDBN}INIT_FILENAME
+The default name of @value{GDBN}'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}.
+@item NO_STD_REGS
+This macro is deprecated.
+
@item NO_SYS_FILE
Define this if your system does not have a @code{<sys/file.h>}.
bfd_seek). FIXME, should be replaced by SEEK_SET instead, which is the
POSIX equivalent.
-@item MAINTENANCE_CMDS
-If the value of this is 1, then a number of optional maintenance
-commands are compiled in.
-
@item MALLOC_INCOMPATIBLE
Define this if the system's prototype for @code{malloc} differs from the
@sc{ANSI} definition.
set correctly if compiling with GCC. This will almost never need to be
defined.
+@item USE_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
+@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
defined.
@item STOP_SIGNAL
-This is the signal for stopping GDB. Defaults to SIGTSTP. (Only
+This is the signal for stopping @value{GDBN}. Defaults to SIGTSTP. (Only
redefined for the Convex.)
@item USE_O_NOCTTY
@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.
+@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.
@section Registers and Memory
-GDB's model of the target machine is rather simple. GDB assumes the
+@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.
-GDB does not have a magical way to match up with the compiler's idea of
+@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.
-GDB can handle big-endian, little-endian, and bi-endian architectures.
+@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_pointer (value_ptr @var{val})
+Assuming that @var{val} is a pointer, return the address it represents,
+as appropriate for the current architecture.
+
+This function actually works on integral values, as well as pointers.
+For pointers, it performs architecture-specific conversions as
+described above for @code{extract_typed_address}.
+@end deftypefun
+
+@deftypefun CORE_ADDR value_from_pointer (struct type *@var{type}, CORE_ADDR @var{addr})
+Create and return a value representing a pointer of type @var{type} to
+the address @var{addr}, as appropriate for the current architecture.
+This function performs architecture-specific conversions as described
+above for @code{store_typed_address}.
+@end deftypefun
+
+
+@value{GDBN} also provides functions that do the same tasks, but assume
+that pointers are simply byte addresses; they aren't sensitive to the
+current architecture, beyond knowing the appropriate endianness.
+
+@deftypefun CORE_ADDR extract_address (void *@var{addr}, int len)
+Extract a @var{len}-byte number from @var{addr} in the appropriate
+endianness for the current architecture, and return it. Note that
+@var{addr} refers to @value{GDBN}'s memory, not the inferior's.
+
+This function should only be used in architecture-specific code; it
+doesn't have enough information to turn bits into a true address in the
+appropriate way for the current architecture. If you can, use
+@code{extract_typed_address} instead.
+@end deftypefun
+
+@deftypefun void store_address (void *@var{addr}, int @var{len}, LONGEST @var{val})
+Store @var{val} at @var{addr} as a @var{len}-byte integer, in the
+appropriate endianness for the current architecture. Note that
+@var{addr} refers to a buffer in @value{GDBN}'s memory, not the
+inferior's.
+
+This function should only be used in architecture-specific code; it
+doesn't have enough information to turn a true address into bits in the
+appropriate way for the current architecture. If you can, use
+@code{store_typed_address} instead.
+@end deftypefun
+
+
+Here are some macros which architectures can define to indicate the
+relationship between pointers and addresses. These have default
+definitions, appropriate for architectures on which all pointers are
+simple 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++ 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++ 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
+
+Some architectures use one representation for a value when it lives in a
+register, but use a different representation when it lives in memory.
+In @value{GDBN}'s terminology, the @dfn{raw} representation is the one used in
+the target registers, and the @dfn{virtual} representation is the one
+used in memory, and within @value{GDBN} @code{struct value} objects.
+
+For almost all data types on almost all architectures, the virtual and
+raw representations are identical, and no special handling is needed.
+However, they do occasionally differ. For example:
+
+@itemize @bullet
+
+@item
+The x86 architecture supports an 80-bit 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 raw /
+virtual conversions:
+
+@deftypefn {Target Macro} int REGISTER_CONVERTIBLE (int @var{reg})
+Return non-zero if register number @var{reg}'s value needs different raw
+and virtual formats.
+
+You should not use @code{REGISTER_CONVERT_TO_VIRTUAL} for a register
+unless this macro returns a non-zero value for that register.
+@end deftypefn
+
+@deftypefn {Target Macro} int REGISTER_RAW_SIZE (int @var{reg})
+The size of register number @var{reg}'s raw value. This is the number
+of bytes the register will occupy in @code{registers}, or in a @value{GDBN}
+remote protocol packet.
+@end deftypefn
+
+@deftypefn {Target Macro} int REGISTER_VIRTUAL_SIZE (int @var{reg})
+The size of register number @var{reg}'s value, in its virtual format.
+This is the size a @code{struct value}'s buffer will have, holding that
+register's value.
+@end deftypefn
+
+@deftypefn {Target Macro} struct type *REGISTER_VIRTUAL_TYPE (int @var{reg})
+This is the type of the virtual representation of register number
+@var{reg}. Note that there is no need for a macro giving a type for the
+register's raw form; once the register's value has been obtained, @value{GDBN}
+always uses the virtual form.
+@end deftypefn
+
+@deftypefn {Target Macro} void REGISTER_CONVERT_TO_VIRTUAL (int @var{reg}, struct type *@var{type}, char *@var{from}, char *@var{to})
+Convert the value of register number @var{reg} to @var{type}, which
+should always be @code{REGISTER_VIRTUAL_TYPE (@var{reg})}. The buffer
+at @var{from} holds the register's value in raw format; the macro should
+convert the value to virtual format, and place it at @var{to}.
+
+Note that @code{REGISTER_CONVERT_TO_VIRTUAL} and
+@code{REGISTER_CONVERT_TO_RAW} take their @var{reg} and @var{type}
+arguments in different orders.
+
+You should only use @code{REGISTER_CONVERT_TO_VIRTUAL} with registers
+for which the @code{REGISTER_CONVERTIBLE} macro returns a non-zero
+value.
+@end deftypefn
+
+@deftypefn {Target Macro} void REGISTER_CONVERT_TO_RAW (struct type *@var{type}, int @var{reg}, char *@var{from}, char *@var{to})
+Convert the value of register number @var{reg} to @var{type}, which
+should always be @code{REGISTER_VIRTUAL_TYPE (@var{reg})}. The buffer
+at @var{from} holds the register's value in raw format; the macro should
+convert the value to virtual format, and place it at @var{to}.
+
+Note that REGISTER_CONVERT_TO_VIRTUAL and REGISTER_CONVERT_TO_RAW take
+their @var{reg} and @var{type} arguments in different orders.
+@end deftypefn
+
@section Frame Interpretation
@item ADDITIONAL_OPTION_HANDLER
@item ADDITIONAL_OPTION_HELP
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)
-If a raw machine 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}. For example, the two low-order bits of
-a Motorola 88K address may be used by some kernels for their own
-purposes, since addresses must always be 4-byte aligned, and so are of
-no use for addressing. Those bits should be filtered out with an
-expression such as @code{((addr) & ~3)}.
+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
+addresses of instructions, and even then not in all contexts.
+
+For example, the two low-order bits of the PC on the Hewlett-Packard PA
+2.0 architecture contain the privilege level of the corresponding
+instruction. Since instructions must always be aligned on four-byte
+boundaries, the processor masks out these bits to generate the actual
+address of the instruction. ADDR_BITS_REMOVE should filter out these
+bits with an expression such as @code{((addr) & ~3)}.
+
+@item ADDRESS_TO_POINTER (@var{type}, @var{buf}, @var{addr})
+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++ reference type.
+@xref{Target Architecture Definition, , Pointers Are Not Always Addresses}.
@item 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.
+for the target, @value{GDBN} 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.
promoted type.
@item BELIEVE_PCC_PROMOTION_TYPE
-Define this if GDB should believe the type of a short argument when
+Define this if @value{GDBN} 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.
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}.
+
@item BIG_BREAKPOINT
@item LITTLE_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}.
+
@item REMOTE_BREAKPOINT
@item LITTLE_REMOTE_BREAKPOINT
@item BIG_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)
Use the program counter to determine the contents and size of a
instruction. The breakpoint must be no longer than the shortest
instruction of the architecture.
-Replaces all the other BREAKPOINTs.
+Replaces all the other @var{BREAKPOINT} macros.
+
+@item MEMORY_INSERT_BREAKPOINT (addr, contents_cache)
+@item MEMORY_REMOVE_BREAKPOINT (addr, contents_cache)
+
+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
+@var{MEMORY_INSERT_BREAKPOINT} and @var{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
+@var{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
+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
+specify the sequence of instructions needed for an inferior function
+call.
+
+Should be deprecated in favour 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}.
@item CALL_DUMMY
-valops.c
+A static initializer for @var{CALL_DUMMY_WORDS}. Deprecated.
+
@item CALL_DUMMY_LOCATION
inferior.h
+
@item CALL_DUMMY_STACK_ADJUST
-valops.c
+Stack adjustment needed when performing an inferior function call.
+
+Should be deprecated in favor of something like @var{STACK_ALIGN}.
+
+@item CALL_DUMMY_STACK_ADJUST_P
+Predicate for use of @var{CALL_DUMMY_STACK_ADJUST}.
+
+Should be deprecated in favor of something like @var{STACK_ALIGN}.
@item CANNOT_FETCH_REGISTER (regno)
A C expression that should be nonzero if @var{regno} cannot be fetched
@item CANNOT_STORE_REGISTER (regno)
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
+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
Currently only implemented correctly for native Sparc configurations?
+@item COERCE_FLOAT_TO_DOUBLE (@var{formal}, @var{actual})
+If we are calling a function by hand, and the function was declared
+(according to the debug info) without a prototype, should we
+automatically promote floats to doubles? This macro must evaluate to
+non-zero if we should, or zero if we should leave the value alone.
+
+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.
+
+The default behavior is to promote only when we have no type information
+for the formal parameter. This is different from the obvious behavior,
+which would be to promote whenever we have no prototype, just as the
+compiler does. It's annoying, but some older targets rely on this. If
+you want @value{GDBN} to follow the typical compiler behavior --- to always
+promote when there is no prototype in scope --- your gdbarch init
+function can call @code{set_gdbarch_coerce_float_to_double} and select
+the @code{standard_coerce_float_to_double} function.
+
@item CPLUS_MARKER
Define this to expand into the character that G++ uses to distinguish
compiler-generated identifiers from programmer-specified identifiers.
@item DO_REGISTERS_INFO
If defined, use this to print the value of a register or all registers.
+@item 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
+Convert DWARF2 register number into @value{GDBN} regnum. If not
+defined, no conversion will be performed.
+
+@item 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 ?)
into @var{valbuf}.
@item EXTRACT_STRUCT_VALUE_ADDRESS(regbuf)
-Define this 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).
+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_P
+Predicate for @var{EXTRACT_STRUCT_VALUE_ADDRESS}.
@item FLOAT_INFO
If defined, then the `info float' command will print information about
the processor's floating point unit.
@item FP_REGNUM
-The number of the frame pointer register.
+If the virtual frame pointer is kept in a register, then define this
+macro to be the number (greater than or equal to zero) of that register.
+
+This should only need to be defined if @code{TARGET_READ_FP} and
+@code{TARGET_WRITE_FP} are not defined.
-@item FRAMELESS_FUNCTION_INVOCATION(fi, frameless)
-Define this to set the variable @var{frameless} to 1 if the function
-invocation represented by @var{fi} does not have a stack frame
-associated with it. Otherwise set it to 0.
+@item FRAMELESS_FUNCTION_INVOCATION(fi)
+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
@item FRAME_CHAIN_VALID(chain,thisframe)
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()}).
+an outermost frame, with no caller, and nonzero otherwise. Several
+common definitions are available.
+
+@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}). @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()}).
+@code{generic_file_frame_chain_valid} and
+@code{generic_func_frame_chain_valid} are equivalent implementations for
+targets using generic dummy frames.
@item FRAME_INIT_SAVED_REGS(frame)
See @file{frame.h}. Determines the address of all registers in the
@var{FRAME_FIND_SAVED_REGS} and @var{EXTRA_FRAME_INFO} are deprecated.
-@item FRAME_NUM_ARGS (val, fi)
-For the frame described by @var{fi}, set @var{val} to the number of arguments
-that are being passed.
+@item FRAME_NUM_ARGS (fi)
+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
@code{FUNCTION_EPILOGUE_SIZE} to expand into the standard size of a
function's epilogue.
+@item FUNCTION_START_OFFSET
+An integer, giving the offset in bytes from a function's address (as
+used in the values of symbols, function pointers, etc.), and the
+function's first genuine instruction.
+
+This is zero on almost all machines: the function's address is usually
+the address of its first instruction. However, on the VAX, for example,
+each function starts with two bytes containing a bitmask indicating
+which registers to save upon entry to the function. The VAX @code{call}
+instructions check this value, and save the appropriate registers
+automatically. Thus, since the offset from the function's address to
+its first instruction is two bytes, @code{FUNCTION_START_OFFSET} would
+be 2 on the VAX.
+
@item GCC_COMPILED_FLAG_SYMBOL
@item GCC2_COMPILED_FLAG_SYMBOL
-If defined, these are the names of the symbols that GDB will look for to
+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 GDB_TARGET_IS_HPPA
+@item @value{GDBN}_MULTI_ARCH
+If defined and non-zero, enables suport for multiple architectures
+within @value{GDBN}.
+
+The support can be enabled at two levels. At level one, only
+definitions for previously undefined macros are provided; at level two,
+a multi-arch definition of all architecture dependant macros will be
+defined.
+
+@item @value{GDBN}_TARGET_IS_HPPA
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 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
@item GET_SAVED_REGISTER
Define this if you need to supply your own definition for the function
-@code{get_saved_register}. Currently this is only done for the a29k.
+@code{get_saved_register}.
@item HAVE_REGISTER_WINDOWS
Define this if the target has register windows.
feature-specific macros. It was introduced in haste and we are
repenting at leisure.
+@item SYMBOLS_CAN_START_WITH_DOLLAR
+Some systems have routines whose names start with @samp{$}. Giving this
+macro a non-zero value tells @value{GDBN}'s expression parser to check for such
+routines when parsing tokens that begin with @samp{$}.
+
+On HP-UX, certain system routines (millicode) have names beginning with
+@samp{$} or @samp{$$}. For example, @code{$$dyncall} is a millicode
+routine that handles inter-space procedure calls on PA-RISC.
+
@item IEEE_FLOAT
Define this if the target system uses IEEE-format floating point numbers.
Define this to evaluate to nonzero if the program is stopped in the
trampoline that returns from a shared library.
+@item IN_SOLIB_DYNSYM_RESOLVE_CODE pc
+Define this to evaluate to nonzero if the program is stopped in the
+dynamic linker.
+
+@item SKIP_SOLIB_RESOLVER pc
+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 IS_TRAPPED_INTERNALVAR (name)
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
+Define this if @value{GDBN} should determine the start and end addresses of the
text section. (Seems dubious.)
@item NO_HIF_SUPPORT
(Specific to the a29k.)
+@item POINTER_TO_ADDRESS (@var{type}, @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.
+@xref{Target Architecture Definition, , Pointers Are Not Always Addresses}.
+
+@item REGISTER_CONVERTIBLE (@var{reg})
+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})
+Return the raw size of @var{reg}.
+@xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}.
+
+@item REGISTER_VIRTUAL_SIZE (@var{reg})
+Return the virtual size of @var{reg}.
+@xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}.
+
+@item REGISTER_VIRTUAL_TYPE (@var{reg})
+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})
+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})
+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++, 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
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.
the next instruction. See @code{sparc-tdep.c} and @code{rs6000-tdep.c}
for examples.
+@item 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
(Used only in the Convex target.)
@item PC_REGNUM
If the program counter is kept in a register, then define this macro to
-be the number of that register. This need be defined only if
-@code{TARGET_WRITE_PC} is not defined.
+be the number (greater than or equal to zero) of that register.
+
+This should only need to be defined if @code{TARGET_READ_PC} and
+@code{TARGET_WRITE_PC} are not defined.
@item NPC_REGNUM
The number of the ``next program counter'' register, if defined.
The number of the ``next next program counter'' register, if defined.
Currently, this is only defined for the Motorola 88K.
+@item PARM_BOUNDARY
+If non-zero, round arguments to a boundary of this many bits before
+pushing them on the stack.
+
@item PRINT_REGISTER_HOOK (regno)
If defined, this must be a function that prints the contents of the
given register to standard output.
@item POP_FRAME
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)
-Define this to push arguments onto the stack for inferior function call.
+Define this to push arguments onto the stack for inferior function
+call. Return the updated stack pointer value.
@item 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
+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_NAMES
+Deprecated in favor of @var{REGISTER_NAME}.
+
@item REG_STRUCT_HAS_ADDR (gcc_p, type)
Define this to return 1 if the given type will be passed by pointer
rather than directly.
+@item SAVE_DUMMY_FRAME_TOS (sp)
+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
+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
+Define this to convert sdb register numbers into @value{GDBN} regnums. If not
defined, no conversion will be done.
@item SHIFT_INST_REGS
(Only used for m88k targets.)
+@item 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 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 (pc)
-A C statement that advances the @var{pc} across any function entry
-prologue instructions so as to reach ``real'' code.
+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 statement that should behave similarly, but that can stop as soon as
-the function is known to have a frame. If not defined,
+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)
that is at the start of the real function.
@item SP_REGNUM
-Define this to be the number of the register that serves as the stack
-pointer.
+If the stack-pointer is kept in a register, then define this macro to be
+the number (greater than or equal to zero) of that register.
+
+This should only need to be defined if @code{TARGET_WRITE_SP} and
+@code{TARGET_WRITE_SP} are not defined.
@item STAB_REG_TO_REGNUM
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 STEP_SKIPS_DELAY (addr)
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 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
Number of bits in a double float; defaults to @code{8 * TARGET_CHAR_BIT}.
@item 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
Number of bits in a float; defaults to @code{4 * TARGET_CHAR_BIT}.
@item TARGET_WRITE_FP
These change the behavior of @code{read_pc}, @code{write_pc},
@code{read_sp}, @code{write_sp}, @code{read_fp} and @code{write_fp}.
-For most targets, these may be left undefined. GDB will call the read
+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
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.
@section Adding a New Target
-The following files define a target to GDB:
+The following files define a target to @value{GDBN}:
@table @file
@item gdb/config/@var{arch}/@var{ttt}.mt
Contains a Makefile fragment specific to this target. Specifies what
object files are needed for target @var{ttt}, by defining
-@samp{TDEPFILES=@dots{}}. Also specifies the header file which
-describes @var{ttt}, by defining @samp{TM_FILE= tm-@var{ttt}.h}. You
-can also define @samp{TM_CFLAGS}, @samp{TM_CLIBS}, @samp{TM_CDEPS}, 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}.
+
+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/config/@var{arch}/tm-@var{ttt}.h
(@file{tm.h} is a link to this file, created by configure). Contains
@chapter Target Vector Definition
-The target vector defines the interface between GDB's abstract handling
+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. GDB includes some 30-40
-different target vectors; however, each configuration of GDB includes
+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
+@value{GDBN}'s file @file{remote.c} talks a serial protocol to code that runs in
+the target system. @value{GDBN} provides several sample ``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
+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.
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
@chapter Native Debugging
-Several files control GDB's configuration for native support:
+Several files control @value{GDBN}'s configuration for native support:
@table @file
@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
@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
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
+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 Native Conditionals
-When GDB is configured and compiled, various macros are defined or left
+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
+If defined, then @value{GDBN} will include support for the @code{attach} and
@code{detach} commands.
@item CHILD_PREPARE_TO_STORE
@item KERNEL_U_ADDR
Define this to the address of the @code{u} structure (the ``user
-struct'', also known as the ``u-page'') in kernel virtual memory. GDB
+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
+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
+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.
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}
+This (ugly) macro allows a native configuration to customize the way the
+@code{proceed} function in @file{infrun.c} deals with switching between
+threads.
+
+In a multi-threaded task we may select another thread and then continue
+or step. But if the old thread was stopped at a breakpoint, it will
+immediately cause another breakpoint stop without any execution (i.e. it
+will report a breakpoint hit incorrectly). So @value{GDBN} must step over it
+first.
+
+If defined, @code{PREPARE_TO_PROCEED} should check the current thread
+against the thread that reported the most recent event. If a step-over
+is required, it returns TRUE. If @var{select_it} is non-zero, it should
+reselect the old thread.
+
@item PROC_NAME_FMT
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
@item SOLIB_ADD (filename, from_tty, targ)
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.
@item 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
+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 USE_PROC_FS
This determines whether small routines in @file{*-tdep.c}, which
-translate register values between GDB's internal representation and the
+translate register values between @value{GDBN}'s internal representation and the
/proc representation, are compiled.
@item U_REGS_OFFSET
@section BFD
-BFD provides support for GDB in several ways:
+BFD provides support for @value{GDBN} in several ways:
@table @emph
@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
+(such as the text section or the data section). @value{GDBN} simply calls BFD to
read or write section X at byte offset Y for length Z.
@item specialized core file support
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
-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
@chapter Coding
This chapter covers topics that are lower-level than the major
-algorithms of GDB.
+algorithms of @value{GDBN}.
@section Cleanups
to unfiltered (``@code{printf}'') output. Symbol reading routines that
print warnings are a good example.
-@section GDB Coding Standards
+@section @value{GDBN} 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
+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, GDB requires it.
+does not require it, @value{GDBN} requires it.
-GDB follows an additional set of coding standards specific to GDB,
+@value{GDBN} follows an additional set of coding standards specific to @value{GDBN},
as described in the following sections.
-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}.
+You can configure with @samp{--enable-build-warnings} or
+@samp{--enable-gdb-build-warnings} to get GCC to check on a number of
+these rules. @value{GDBN} sources ought not to engender any complaints,
+unless they are caused by bogus host systems. (The exact set of enabled
+warnings is currently @samp{-Wimplicit -Wreturn-type -Wcomment
+-Wtrigraphs -Wformat -Wparentheses -Wpointer-arith -Wuninitialized}.
@subsection Formatting
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
+zero; in a function declaration, the name must be on the same line as
the return type.
In addition, there must be a space between a function or macro name and
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. */
+ stopped and @value{GDBN} should read more commands. */
@end example
(Note that this format is encouraged by Emacs; tabbing for a multi-line
of evaluation of expressions.
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
+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 one thousand-line function.
+are just as hard to understand as a single thousand-line function.
@subsection 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 to @emph{declare} functions, and may be used to
+@emph{define} them. 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:
-
-@example @code
-extern int memory_remove_breakpoint PARAMS ((CORE_ADDR addr,
- char *contents_cache));
-@end example
-
-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:
-
-@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.
-
-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 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.
All static functions must be declared in a block near the top of the
source file.
@subsection Clean 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.
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
+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
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
+found in @code{get_saved_register}. All machines that @value{GDBN} 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
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
+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 #ifdef's everywhere, but
by defining the "target_ops" structure and having a current target (as
well as a stack of targets below it, for memory references). Whenever
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 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,
+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, #if defined, etc.), and
machines which are radically different don't need to use infptrace.c at
all.
+Don't put debugging printfs in the code.
@node Porting GDB
-@chapter Porting GDB
+@chapter Porting @value{GDBN}
-Most of the work in making GDB compile on a new machine is in specifying
+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.
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
+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
+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.
-@section Configuring GDB for Release
+@section Configuring @value{GDBN} for Release
From the top level directory (containing @file{gdb}, @file{bfd},
@file{libiberty}, and so on):
@code{makeinfo} will split the document into one overall file and five
or so included files.
+@node Testsuite
+
+@chapter Testsuite
+
+The testsuite is an important component of the @value{GDBN} package. While it is
+always worthwhile to encourage user testing, in practice this is rarely
+sufficient; users typically use only a small subset of the available
+commands, and it has proven all too common for a change to cause a
+significant regression that went unnoticed for some time.
+
+The @value{GDBN} testsuite uses the DejaGNU testing framework. DejaGNU is built
+using tcl and expect. The tests themselves are calls to various 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 @value{GDBN} object directory (or to the
+testsuite's objdir) and type @code{make check}. This just sets up some
+environment variables and invokes DejaGNU's @code{runtest} script. While
+the testsuite is running, you'll get mentions of which test file is in use,
+and a mention of any unexpected passes or fails. When the testsuite is
+finished, you'll get a summary that looks like this:
+@example
+ === gdb Summary ===
+
+# of expected passes 6016
+# of unexpected failures 58
+# of unexpected successes 5
+# of expected failures 183
+# of unresolved testcases 3
+# of untested testcases 5
+@end example
+The ideal test run consists of expected passes only; however, reality
+conspires to keep us from this ideal. Unexpected failures indicate
+real problems, whether in @value{GDBN} or in the testsuite. Expected failures
+are still failures, but ones which have been decided are too hard to
+deal with at the time; for instance, a test case might work everywhere
+except on AIX, and there is no prospect of the AIX case being fixed in
+the near future. Expected failures should not be added lightly, since
+you may be masking serious bugs in @value{GDBN}. Unexpected successes are expected
+fails that are passing for some reason, while unresolved and untested
+cases often indicate some minor catastrophe, such as the compiler being
+unable to deal with a test program.
+
+When making any significant change to @value{GDBN}, you should run the testsuite
+before and after the change, to confirm that there are no regressions.
+Note that truly complete testing would require that you run the
+testsuite with all supported configurations and a variety of compilers;
+however this is more than really necessary. In many cases testing with
+a single configuration is sufficient. Other useful options are to test
+one big-endian (Sparc) and one little-endian (x86) host, a cross config
+with a builtin simulator (powerpc-eabi, mips-elf), or a 64-bit host
+(Alpha).
+
+If you add new functionality to @value{GDBN}, please consider adding tests for it
+as well; this way future @value{GDBN} hackers can detect and fix their changes
+that break the functionality you added. Similarly, if you fix a bug
+that was not previously reported as a test failure, please add a test
+case for it. Some cases are extremely difficult to test, such as code
+that handles host OS failures or bugs in particular versions of
+compilers, and it's OK not to try to write tests for all of those.
+
+@section Testsuite Organization
+
+The testsuite is entirely contained in @file{gdb/testsuite}. While the
+testsuite includes some makefiles and configury, these are very minimal,
+and used for little besides cleaning up, since the tests themselves
+handle the compilation of the programs that @value{GDBN} will run. The file
+@file{testsuite/lib/gdb.exp} contains common utility procs useful for
+all @value{GDBN} tests, while the directory @file{testsuite/config} contains
+configuration-specific files, typically used for special-purpose
+definitions of procs like @code{gdb_load} and @code{gdb_start}.
+
+The tests themselves are to be found in @file{testsuite/gdb.*} and
+subdirectories of those. The names of the test files must always end
+with @file{.exp}. DejaGNU collects the test files by wildcarding
+in the test directories, so both subdirectories and individual files
+get chosen and run in alphabetical order.
+
+The following table lists the main types of subdirectories and what they
+are for. Since DejaGNU finds test files no matter where they are
+located, and since each test file sets up its own compilation and
+execution environment, this organization is simply for convenience and
+intelligibility.
+
+@table @code
+
+@item gdb.base
+
+This is the base testsuite. The tests in it should apply to all
+configurations of @value{GDBN} (but generic native-only tests may live here).
+The test programs should be in the subset of C that is valid K&R,
+ANSI/ISO, and C++ (ifdefs are allowed if necessary, for instance
+for prototypes).
+
+@item gdb.@var{lang}
+
+Language-specific tests for all languages 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 @value{GDBN}'s handling of GCC extensions.
+
+@item gdb.@var{subsystem}
+
+Tests that exercise a specific @value{GDBN} subsystem in more depth. For
+instance, @file{gdb.disasm} exercises various disassemblers, while
+@file{gdb.stabs} tests pathways through the stabs symbol reader.
+
+@end table
+
+@section Writing Tests
+
+In many areas, the @value{GDBN} tests are already quite comprehensive; you
+should be able to copy existing tests to handle new cases.
+
+You should try to use @code{gdb_test} whenever possible, since it
+includes cases to handle all the unexpected errors that might happen.
+However, it doesn't cost anything to add new test procedures; for
+instance, @file{gdb.base/exprs.exp} defines a @code{test_expr} that
+calls @code{gdb_test} multiple times.
+
+Only use @code{send_gdb} and @code{gdb_expect} when absolutely
+necessary, such as when @value{GDBN} has several valid responses to a command.
+
+The source language programs do @emph{not} need to be in a consistent
+style. Since @value{GDBN} is used to debug programs written in many different
+styles, it's worth having a mix of styles in the testsuite; for
+instance, some @value{GDBN} bugs involving the display of source lines would
+never manifest themselves if the programs used GNU coding style
+uniformly.
+
@node Hints
@chapter Hints
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
+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
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}
+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
@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
+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}.
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
-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
./gdb}}, which works on Suns and such, you can copy @file{gdb} to
@file{gdb2} and then type @code{@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
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. You
-may not always agree on what is clean design.
-@c @pxref{Coding Style}, @pxref{Clean Design}.
+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
The legal issue is that to incorporate substantial changes requires a
copyright assignment from you and/or your employer, granting ownership
of the changes to the Free Software Foundation. You can get the
-standard document for doing this by sending mail to
-@code{gnu@@prep.ai.mit.edu} and asking for it. I recommend that people
-write in "All programs owned by the Free Software Foundation" as "NAME
-OF PROGRAM", so that changes in many programs (not just GDB, but GAS,
-Emacs, GCC, etc) can be contributed with only one piece of legalese
-pushed through the bureacracy and filed with the FSF. I can't start
-merging changes until this paperwork is received by the FSF (their
-rules, which I follow since I maintain it for them).
+standard documents for doing this by sending mail to @code{gnu@@gnu.org}
+and asking for it. We recommend that people write in "All programs
+owned by the Free Software Foundation" as "NAME OF PROGRAM", so that
+changes in many programs (not just @value{GDBN}, but GAS, Emacs, GCC, etc) can be
+contributed with only one piece of legalese pushed through the
+bureacracy 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.texi or gdb/doc/gdbint.texi). If there
-are a lot of changes for a single feature, they can be split down
-into multiple messages.
-
-In this way, if I read and like the feature, I can add it to the
+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.
+
+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, I have to write one. If you leave
-out the doc, I have to puzzle out what needs documenting. Etc.
+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.
-The reason to send each change in a separate message is that I will
-not install some of the changes. They'll be returned to you with
-questions or comments. If I'm doing my job, my message back to you
+The reason to send each change in a separate message is that we will not
+install some of the changes. They'll be returned to you with questions
+or comments. If we're doing our job correctly, the message back to you
will say what you have to fix in order to make the change acceptable.
-The reason to have separate messages for separate features is so
-that other changes (which I @emph{am} willing to accept) can be installed
-while one or more changes are being reworked. If multiple features
-are sent in a single message, I tend to not put in the effort to sort
-out the acceptable changes from the unacceptable, so none of the
-features get installed until all are acceptable.
-
-If this sounds painful or authoritarian, well, it is. But I get a lot
-of bug reports and a lot of patches, and most of them don't get
-installed because I don't have the time to finish the job that the bug
+The reason to have separate messages for separate features is so that
+the acceptable changes can be installed while one or more changes are
+being reworked. If multiple features are sent in a single message, we
+tend to not put in the effort to sort out the acceptable changes from
+the unacceptable, so none of the features get installed until all are
+acceptable.
+
+If this sounds painful or authoritarian, well, it is. But we get a lot
+of bug reports and a lot of patches, and many of them don't get
+installed because we don't have the time to finish the job that the bug
reporter or the contributor could have done. Patches that arrive
complete, working, and well designed, tend to get installed on the day
-they arrive. The others go into a queue and get installed if and when
-I scan back over the queue -- which can literally take months
-sometimes. It's in both our interests to make patch installation easy
--- you get your changes installed, and I make some forward progress on
-GDB in a normal 12-hour day (instead of them having to wait until I
-have a 14-hour or 16-hour day to spend cleaning up patches before I
-can install them).
+they arrive. The others go into a queue and get installed as time
+permits, which, since the maintainers have many demands to meet, may not
+be for quite some time.
-Please send patches directly to the GDB maintainers at
-@code{gdb-patches@@cygnus.com}.
+Please send patches directly to the @value{GDBN} maintainers at
+@code{gdb-patches@@sourceware.cygnus.com}.
@section Obsolete Conditionals
-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.
@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!
@end table
-
+@c TeX can handle the contents at the start but makeinfo 3.12 can not
+@ifinfo
@contents
+@end ifinfo
+@ifhtml
+@contents
+@end ifhtml
+
@bye
projects / deliverable / binutils-gdb.git / blobdiff