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mailing list for the GDB project.
Re: RFA: distinguish between pointers and addresses
- To: Stan Shebs <shebs at apple dot com>
- Subject: Re: RFA: distinguish between pointers and addresses
- From: Daniel Berlin <dan at cgsoftware dot com>
- Date: Tue, 11 Apr 2000 11:56:54 -0700 (PDT)
- cc: gdb-patches at sourceware dot cygnus dot com
On Tue, 11 Apr 2000, Stan Shebs wrote:
>
> Well, gdbint.texinfo is a less formal document, and its audience
> is considerably smaller than for the regular manual. On the
> other hand, it saves valuable brain cells when we can use a
> consistent set of rules for all of our documents, and who knows,
> perhaps one day we'll want to follow GCC's example and put our
> internals info into the regular GDB manual (hmmm, maybe not :-) ).
>
> So I'd say we should start using @value{GDBN} and our other
> doc conventions in gdbint.texinfo, converting things other as
> time allows.
Here's a patch that takes care of the @value{GDBN} part of it.
>
> Stan
>
Index: gdbint.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdbint.texinfo,v
retrieving revision 1.7
diff -c -3 -p -r1.7 gdbint.texinfo
*** gdbint.texinfo 2000/04/10 15:50:02 1.7
--- gdbint.texinfo 2000/04/11 18:55:54
***************
*** 1,6 ****
\input texinfo
@setfilename gdbint.info
!
@ifinfo
@format
START-INFO-DIR-ENTRY
--- 1,6 ----
\input texinfo
@setfilename gdbint.info
! @include gdb-cfg.texi
@ifinfo
@format
START-INFO-DIR-ENTRY
*************** END-INFO-DIR-ENTRY
*** 10,16 ****
@end ifinfo
@ifinfo
! This file documents the internals of the GNU debugger GDB.
Copyright 1990-1999 Free Software Foundation, Inc.
Contributed by Cygnus Solutions. Written by John Gilmore.
--- 10,16 ----
@end ifinfo
@ifinfo
! 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.
*************** regarded as a program in the language Te
*** 33,42 ****
@end ifinfo
@setchapternewpage off
! @settitle GDB Internals
@titlepage
! @title{GDB Internals}
@subtitle{A guide to the internals of the GNU debugger}
@author John Gilmore
@author Cygnus Solutions
--- 33,42 ----
@end ifinfo
@setchapternewpage off
! @settitle @value{GDBN} Internals
@titlepage
! @title @value{GDBN} Internals
@subtitle{A guide to the internals of the GNU debugger}
@author John Gilmore
@author Cygnus Solutions
*************** are preserved on all copies.
*** 68,76 ****
@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.
@menu
* Requirements::
--- 68,76 ----
@c not for TeX). Existing GNU manuals seem inconsistent on this point.
@top Scope of this Document
! This document documents the internals of the GNU debugger, @value{GDBN}. It
! includes description of @value{GDBN}'s key algorithms and operations, as well
! as the mechanisms that adapt @value{GDBN} to specific hosts and targets.
@menu
* Requirements::
*************** as the mechanisms that adapt GDB to spec
*** 95,135 ****
@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
these requirements.
! First of all, GDB is a debugger. It's not designed to be a front panel
for embedded systems. It's not a text editor. It's not a shell. It's
not a programming environment.
! GDB is an interactive tool. Although a batch mode is available, GDB's
primary role is to interact with a human programmer.
! GDB should be responsive to the user. A programmer hot on the trail of
a nasty bug, and operating under a looming deadline, is going to be very
impatient of everything, including the response time to debugger
commands.
! GDB should be relatively permissive, such as for expressions. While the
compiler should be picky (or have the option to be made picky), since
source code lives for a long time usually, the programmer doing
debugging shouldn't be spending time figuring out to mollify the
debugger.
! GDB will be called upon to deal with really large programs. Executable
sizes of 50 to 100 megabytes occur regularly, and we've heard reports of
programs approaching 1 gigabyte in size.
! GDB should be able to run everywhere. No other debugger is available
! for even half as many configurations as GDB supports.
@node Overall Structure
@chapter Overall Structure
! GDB consists of three major subsystems: user interface, symbol handling
(the ``symbol side''), and target system handling (the ``target side'').
Ther user interface consists of several actual interfaces, plus
--- 95,135 ----
@chapter Requirements
Before diving into the internals, you should understand the formal
! requirements and other expectations for @value{GDBN}. Although some of these may
! seem obvious, there have been proposals for @value{GDBN} that have run counter to
these requirements.
! 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.
! @value{GDBN} is an interactive tool. Although a batch mode is available, @value{GDBN}'s
primary role is to interact with a human programmer.
! @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.
! @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.
! @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.
! @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
! @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
*************** should fit together.
*** 151,176 ****
@section The Symbol Side
! The symbolic side of GDB can be thought of as ``everything you can do in
! GDB without having a live program running''. For instance, you can look
at the types of variables, and evaluate many kinds of expressions.
@section The Target Side
! The target side of GDB is the ``bits and bytes manipulator''. Although
it may make reference to symbolic info here and there, most of the
target side will run with only a stripped executable available -- or
even no executable at all, in remote debugging cases.
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
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{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.
--- 151,176 ----
@section The Symbol Side
! The symbolic side of @value{GDBN} can be thought of as ``everything you can do in
! @value{GDBN} without having a live program running''. For instance, you can look
at the types of variables, and evaluate many kinds of expressions.
@section The Target Side
! 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, @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 @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.
*************** are really part of the target environmen
*** 196,202 ****
@code{#include} files that are only available on the host system. Core
file handling and @code{setjmp} handling are two common cases.
! When you want to make GDB work ``native'' on a particular machine, you
have to include all three kinds of information.
--- 196,202 ----
@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 @value{GDBN} work ``native'' on a particular machine, you
have to include all three kinds of information.
*************** have to include all three kinds of infor
*** 204,221 ****
@chapter Algorithms
! GDB uses a number of debugging-specific algorithms. They are often not
very complicated, but get lost in the thicket of special cases and
real-world issues. This chapter describes the basic algorithms and
mentions some of the specific target definitions that they use.
@section Frames
! A frame is a construct that GDB 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
a new frame from scratch, as follows:
@example
--- 204,221 ----
@chapter Algorithms
! @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 @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 @value{GDBN}, except that it is used when setting up
a new frame from scratch, as follows:
@example
*************** any value that is convenient for the cod
*** 229,236 ****
defined; that is where you should use the @code{FP_REGNUM} value, if
your frames are nonstandard.)
! Given a GDB frame, define @code{FRAME_CHAIN} to determine the address of
! the calling function's frame. This will be used to create a new GDB
frame struct, and then @code{INIT_EXTRA_FRAME_INFO} and
@code{INIT_FRAME_PC} will be called for the new frame.
--- 229,236 ----
defined; that is where you should use the @code{FP_REGNUM} value, if
your frames are nonstandard.)
! 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.
*************** Hardware breakpoints are sometimes avail
*** 247,271 ****
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
emulator is in use; many emulators include circuitry that watches the
address lines coming out from the processor, and force it to stop if the
address matches a breakpoint's address. A third possibility is that the
target already has the ability to do breakpoints somehow; for instance,
a ROM monitor may do its own software breakpoints. So although these
! are not literally ``hardware breakpoints'', from GDB's point of view
! they work the same; GDB need not do nothing more than set the breakpoint
and wait for something to happen.
Since they depend on hardware resources, hardware breakpoints may be
! limited in number; when the user asks for more, GDB will start trying to
set software breakpoints.
! Software breakpoints require GDB to do somewhat more work. The basic
! theory is that GDB will replace a program instruction with 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
instruction, single-step, re-insert the trap, and continue on.
Since it literally overwrites the program being tested, the program area
--- 247,271 ----
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 @value{GDBN}. Another possibility is when an
emulator is in use; many emulators include circuitry that watches the
address lines coming out from the processor, and force it to stop if the
address matches a breakpoint's address. A third possibility is that the
target already has the ability to do breakpoints somehow; for instance,
a ROM monitor may do its own software breakpoints. So although these
! are not literally ``hardware breakpoints'', from @value{GDBN}'s point of view
! they work the same; @value{GDBN} need not do nothing more than set the breakpoint
and wait for something to happen.
Since they depend on hardware resources, hardware breakpoints may be
! limited in number; when the user asks for more, @value{GDBN} will start trying to
set software breakpoints.
! 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
*************** much of the interesting breakpoint actio
*** 300,306 ****
@section Longjmp Support
! GDB has support for figuring out that the target is doing a
@code{longjmp} and for stopping at the target of the jump, if we are
stepping. This is done with a few specialized internal breakpoints,
which are visible in the @code{maint info breakpoint} command.
--- 300,306 ----
@section Longjmp Support
! @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.
*************** is target specific, you will need to def
*** 316,327 ****
@chapter User Interface
! GDB 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
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.
--- 316,327 ----
@chapter User 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 @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.
*************** entire string the user should type at th
*** 354,372 ****
@section libgdb
@code{libgdb} was an abortive project of years ago. The theory was to
! provide an API to GDB's functionality.
@node Symbol Handling
@chapter Symbol Handling
! Symbols are a key part of GDB's operation. Symbols include variables,
functions, and types.
@section Symbol Reading
! GDB reads symbols from ``symbol files''. The usual symbol file is the
! file containing the program which GDB is debugging. GDB can be directed
to use a different file for symbols (with the @code{symbol-file}
command), and it can also read more symbols via the ``add-file'' and
``load'' commands, or while reading symbols from shared libraries.
--- 354,372 ----
@section libgdb
@code{libgdb} was an abortive project of years ago. The theory was to
! provide an API to @value{GDBN}'s functionality.
@node Symbol Handling
@chapter Symbol Handling
! Symbols are a key part of @value{GDBN}'s operation. Symbols include variables,
functions, and types.
@section Symbol Reading
! @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.
*************** BFD library. BFD identifies the type of
*** 376,382 ****
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
@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,
--- 376,382 ----
header. @code{find_sym_fns} then uses this identification to locate a
set of symbol-reading functions.
! 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,
*************** There is no result from @code{@var{xyz}_
*** 410,416 ****
Called from @code{symbol_file_add} when discarding existing symbols.
This function need only handle the symbol-reading module's internal
! state; the symbol table data structures visible to the rest of GDB will
be discarded by @code{symbol_file_add}. It has no arguments and no
result. It may be called after @code{@var{xyz}_symfile_init}, if a new
symbol table is being read, or may be called alone if all symbols are
--- 410,416 ----
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 @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
*************** or dynamically loaded file) is being rea
*** 432,438 ****
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.
@table @code
@item @var{xyz}_psymtab_to_symtab (struct partial_symtab *pst)
--- 432,438 ----
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 @value{GDBN} symbol-handling code.
@table @code
@item @var{xyz}_psymtab_to_symtab (struct partial_symtab *pst)
*************** zero if there were no symbols in that pa
*** 447,453 ****
@section Partial Symbol Tables
! GDB has three types of symbol tables.
@itemize @bullet
--- 447,453 ----
@section Partial Symbol Tables
! @value{GDBN} has three types of symbol tables.
@itemize @bullet
*************** A psymtab is constructed by doing a very
*** 469,475 ****
file's debugging information. Small amounts of information are
extracted -- enough to identify which parts of the symbol table will
need to be re-read and fully digested later, when the user needs the
! information. The speed of this pass causes GDB to start up very
quickly. Later, as the detailed rereading occurs, it occurs in small
pieces, at various times, and the delay therefrom is mostly invisible to
the user.
--- 469,475 ----
file's debugging information. Small amounts of information are
extracted -- enough to identify which parts of the symbol table will
need to be re-read and fully digested later, when the user needs the
! information. The speed of this pass causes @value{GDBN} to start up very
quickly. Later, as the detailed rereading occurs, it occurs in small
pieces, at various times, and the delay therefrom is mostly invisible to
the user.
*************** them anyway. Psymtabs don't have the id
*** 515,521 ****
either, so types need not appear, unless they will be referenced by
name.
! It is a bug for GDB to behave one way when only a psymtab has been read,
and another way if the corresponding symtab has been read in. Such bugs
are typically caused by a psymtab that does not contain all the visible
symbols, or which has the wrong instruction address ranges.
--- 515,521 ----
either, so types need not appear, unless they will be referenced by
name.
! 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.
*************** unless you want to do a lot more work.
*** 532,545 ****
Fundamental Types (e.g., FT_VOID, FT_BOOLEAN).
! These are the fundamental types that GDB uses internally. Fundamental
types from the various debugging formats (stabs, ELF, etc) are mapped
into one of these. They are basically a union of all fundamental types
! that gdb knows about for all the languages that GDB knows about.
Type Codes (e.g., TYPE_CODE_PTR, TYPE_CODE_ARRAY).
! Each time GDB builds an internal type, it marks it with one of these
types. The type may be a fundamental type, such as TYPE_CODE_INT, or a
derived type, such as TYPE_CODE_PTR which is a pointer to another type.
Typically, several FT_* types map to one TYPE_CODE_* type, and are
--- 532,545 ----
Fundamental Types (e.g., FT_VOID, FT_BOOLEAN).
! 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 @value{GDBN} knows about.
Type Codes (e.g., TYPE_CODE_PTR, TYPE_CODE_ARRAY).
! 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
*************** type is signed or unsigned, and how many
*** 549,555 ****
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
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
--- 549,555 ----
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 @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
*************** been run (or the core file has been read
*** 614,620 ****
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
COFF reader.
@subsection ELF
--- 614,620 ----
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, @value{GDBN} needs only the basic
COFF reader.
@subsection ELF
*************** The SOM reader is in @file{hpread.c}.
*** 634,640 ****
@subsection Other File Formats
! Other file formats that have been supported by GDB include Netware
Loadable Modules (@file{nlmread.c}.
@section Debugging File Formats
--- 634,640 ----
@subsection Other File Formats
! Other file formats that have been supported by @value{GDBN} include Netware
Loadable Modules (@file{nlmread.c}.
@section Debugging File Formats
*************** The DWARF 2 reader is in @file{dwarf2rea
*** 687,693 ****
Like COFF, the SOM definition includes debugging information.
! @section Adding a New Symbol Reader to GDB
If you are using an existing object file format (a.out, COFF, ELF, etc),
there is probably little to be done.
--- 687,693 ----
Like COFF, the SOM definition includes debugging information.
! @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.
*************** If you need to add a new object file for
*** 696,704 ****
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
from BFD and a few other BFD internal routines to locate the debugging
! information. As much as possible, GDB should not depend on the BFD
internal data structures.
For some targets (e.g., COFF), there is a special transfer vector used
--- 696,704 ----
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 @value{GDBN} will have to call swapping routines
from BFD and a few other BFD internal routines to locate the debugging
! information. As much as possible, @value{GDBN} should not depend on the BFD
internal data structures.
For some targets (e.g., COFF), there is a special transfer vector used
*************** to call swapping routines, since the ext
*** 706,729 ****
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.
@node Language Support
@chapter Language Support
! GDB's language support is mainly driven by the symbol reader, although
it is possible for the user to set the source language manually.
! GDB chooses the source language by looking at the extension of the file
recorded in the debug info; @code{.c} means C, @code{.f} means Fortran,
etc. It may also use a special-purpose language identifier if the debug
format supports it, such as DWARF.
! @section Adding a Source Language to GDB
! To add other languages to GDB's expression parser, follow the following
steps:
@table @emph
--- 706,729 ----
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 @value{GDBN}.
@node Language Support
@chapter Language Support
! @value{GDBN}'s language support is mainly driven by the symbol reader, although
it is possible for the user to set the source language manually.
! @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 @value{GDBN}
! To add other languages to @value{GDBN}'s expression parser, follow the following
steps:
@table @emph
*************** various parsers from defining the same g
*** 760,766 ****
At the bottom of your parser, define a @code{struct language_defn} and
initialize it with the right values for your language. Define an
@code{initialize_@var{lang}} routine and have it call
! @samp{add_language(@var{lang}_language_defn)} to tell the rest of GDB
that your language exists. You'll need some other supporting variables
and functions, which will be used via pointers from your
@code{@var{lang}_language_defn}. See the declaration of @code{struct
--- 760,766 ----
At the bottom of your parser, define a @code{struct language_defn} and
initialize it with the right values for your language. Define an
@code{initialize_@var{lang}} routine and have it call
! @samp{add_language(@var{lang}_language_defn)} to tell the rest of @value{GDBN}
that your language exists. You'll need some other supporting variables
and functions, which will be used via pointers from your
@code{@var{lang}_language_defn}. See the declaration of @code{struct
*************** string.
*** 793,799 ****
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.
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.
--- 793,799 ----
Update the function @code{_initialize_language} to include your
language. This function picks the default language upon startup, so is
! dependent upon which languages that @value{GDBN} is built for.
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.
*************** Add a call to @code{@var{lang}_parse()}
*** 814,831 ****
@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
@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
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.
! See the file @file{configure.in} for how GDB is configured for different
languages.
@item Edit @file{Makefile.in}
--- 814,831 ----
@item Use macros to trim code
! The user has the option of building @value{GDBN} for some or all of the
! languages. If the user decides to build @value{GDBN} for the language
@var{lang}, then every file dependent on @file{language.h} will have the
macro @code{_LANG_@var{lang}} defined in it. Use @code{#ifdef}s to
leave out large routines that the user won't need if he or she is not
using your language.
! Note that you do not need to do this in your YACC parser, since if @value{GDBN}
is not build for @var{lang}, then @file{@var{lang}-exp.tab.o} (the
! compiled form of your parser) is not linked into @value{GDBN} at all.
! See the file @file{configure.in} for how @value{GDBN} is configured for different
languages.
@item Edit @file{Makefile.in}
*************** definition machinery anymore.
*** 847,858 ****
@section Adding a New Host
! Most of GDB's host configuration support happens via autoconf. It
! should be rare to need new host-specific definitions. GDB still uses
the host-specific definitions and files listed below, but these mostly
exist for historical reasons, and should eventually disappear.
! Several files control GDB's configuration for host systems:
@table @file
--- 847,858 ----
@section Adding a New Host
! 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 @value{GDBN}'s configuration for host systems:
@table @file
*************** This contains generic TCP support using
*** 909,915 ****
@section Host Conditionals
! When GDB is configured and compiled, various macros are defined or left
undefined, to control compilation based on the attributes of the host
system. These macros and their meanings (or if the meaning is not
documented here, then one of the source files where they are used is
--- 909,915 ----
@section Host Conditionals
! When @value{GDBN} is configured and compiled, various macros are defined or left
undefined, to control compilation based on the attributes of the host
system. These macros and their meanings (or if the meaning is not
documented here, then one of the source files where they are used is
*************** indicated) are:
*** 917,924 ****
@table @code
! @item GDBINIT_FILENAME
! The default name of GDB's initialization file (normally @file{.gdbinit}).
@item MEM_FNS_DECLARED
Your host config file defines this if it includes declarations of
--- 917,924 ----
@table @code
! @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
*************** Define this to 1 if the target is using
*** 1065,1071 ****
call code. See @code{blockframe.c} for more information.
@item USE_MMALLOC
! GDB will use the @code{mmalloc} library for memory allocation for symbol
reading if this symbol is defined. Be careful defining it since there
are systems on which @code{mmalloc} does not work for some reason. One
example is the DECstation, where its RPC library can't cope with our
--- 1065,1071 ----
call code. See @code{blockframe.c} for more information.
@item USE_MMALLOC
! @value{GDBN} will use the @code{mmalloc} library for memory allocation for symbol
reading if this symbol is defined. Be careful defining it since there
are systems on which @code{mmalloc} does not work for some reason. One
example is the DECstation, where its RPC library can't cope with our
*************** Define these to appropriate value for th
*** 1105,1111 ****
defined.
@item STOP_SIGNAL
! This is the signal for stopping GDB. Defaults to SIGTSTP. (Only
redefined for the Convex.)
@item USE_O_NOCTTY
--- 1105,1111 ----
defined.
@item STOP_SIGNAL
! This is the signal for stopping @value{GDBN}. Defaults to SIGTSTP. (Only
redefined for the Convex.)
@item USE_O_NOCTTY
*************** Define this to override the defaults of
*** 1133,1157 ****
@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.
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
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
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.
@section Using Different Register and Memory Data Representations
@cindex raw representation
--- 1133,1157 ----
@chapter Target Architecture Definition
! @value{GDBN}'s target architecture defines what sort of machine-language programs
! @value{GDBN} can work with, and how it works with them.
At present, the target architecture definition consists of a number of C
macros.
@section Registers and Memory
! @value{GDBN}'s model of the target machine is rather simple. @value{GDBN} assumes the
machine includes a bank of registers and a block of memory. Each
register may have a different size.
! @value{GDBN} does not have a magical way to match up with the compiler's idea of
which registers are which; however, it is critical that they do match up
accurately. The only way to make this work is to get accurate
information about the order that the compiler uses, and to reflect that
in the @code{REGISTER_NAME} and related macros.
! @value{GDBN} can handle big-endian, little-endian, and bi-endian architectures.
@section Using Different Register and Memory Data Representations
@cindex raw representation
*************** GDB can handle big-endian, little-endian
*** 1162,1170 ****
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 GDB'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 GDB @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.
--- 1162,1170 ----
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.
*************** type is the raw representation, and the
*** 1182,1189 ****
arrangement is the virtual representation.
@item
! Some 64-bit MIPS targets present 32-bit registers to GDB as 64-bit
! registers, with garbage in their upper bits. GDB 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.
--- 1182,1189 ----
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.
*************** virtual representation.
*** 1191,1199 ****
@end itemize
In general, the raw representation is determined by the architecture, or
! GDB's interface to the architecture, while the virtual representation
! can be chosen for GDB's convenience. GDB's register file,
! @code{registers}, holds the register contents in raw format, and the GDB
remote protocol transmits register values in raw format.
Your architecture may define the following macros to request raw /
--- 1191,1199 ----
@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 /
*************** and virtual formats.
*** 1206,1212 ****
@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 GDB
remote protocol packet.
@end deftypefn
--- 1206,1212 ----
@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
*************** register's value.
*** 1219,1225 ****
@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, GDB
always uses the virtual form.
@end deftypefn
--- 1219,1225 ----
@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
*************** machine.
*** 1262,1268 ****
@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
i960 Nindy target, and should not be used in any other configuration.
@item ADDR_BITS_REMOVE (addr)
--- 1262,1268 ----
@item ADDITIONAL_OPTION_HANDLER
@item ADDITIONAL_OPTION_HELP
These are a set of macros that allow the addition of additional command
! line options to @value{GDBN}. They are currently used only for the unsupported
i960 Nindy target, and should not be used in any other configuration.
@item ADDR_BITS_REMOVE (addr)
*************** Define this to expand into any code that
*** 1283,1289 ****
main loop starts. Although this is not, strictly speaking, a target
conditional, that is how it is currently being used. Note that if a
configuration were to define it one way for a host and a different way
! for the target, GDB will probably not compile, let alone run correctly.
This is currently used only for the unsupported i960 Nindy target, and
should not be used in any other configuration.
--- 1283,1289 ----
main loop starts. Although this is not, strictly speaking, a target
conditional, that is how it is currently being used. Note that if a
configuration were to define it one way for a host and a different way
! for the target, @value{GDBN} will probably not compile, let alone run correctly.
This is currently used only for the unsupported i960 Nindy target, and
should not be used in any other configuration.
*************** still reports the parameter as its origi
*** 1293,1299 ****
promoted type.
@item BELIEVE_PCC_PROMOTION_TYPE
! Define this if GDB should believe the type of a short argument when
compiled by pcc, but look within a full int space to get its value.
Only defined for Sun-3 at present.
--- 1293,1299 ----
promoted type.
@item BELIEVE_PCC_PROMOTION_TYPE
! 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.
*************** from an inferior process. This is only
*** 1400,1406 ****
@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
will assume that all registers may be written.
@item DO_DEFERRED_STORES
--- 1400,1406 ----
@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, @value{GDBN}
will assume that all registers may be written.
@item DO_DEFERRED_STORES
*************** The default behavior is to promote only
*** 1428,1434 ****
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 GDB 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.
--- 1428,1434 ----
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.
*************** be 2 on the VAX.
*** 1559,1579 ****
@item GCC_COMPILED_FLAG_SYMBOL
@item GCC2_COMPILED_FLAG_SYMBOL
! If defined, these are the names of the symbols that GDB will look for to
detect that GCC compiled the file. The default symbols are
@code{gcc_compiled.} and @code{gcc2_compiled.}, respectively. (Currently
only defined for the Delta 68.)
! @item GDB_MULTI_ARCH
If defined and non-zero, enables suport for multiple architectures
! within GDB.
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 GDB_TARGET_IS_HPPA
This determines whether horrible kludge code in dbxread.c and
partial-stab.h is used to mangle multiple-symbol-table files from
HPPA's. This should all be ripped out, and a scheme like elfread.c
--- 1559,1579 ----
@item GCC_COMPILED_FLAG_SYMBOL
@item GCC2_COMPILED_FLAG_SYMBOL
! If defined, these are the names of the symbols that @value{GDBN} will look for to
detect that GCC compiled the file. The default symbols are
@code{gcc_compiled.} and @code{gcc2_compiled.}, respectively. (Currently
only defined for the Delta 68.)
! @item @value{GDBN}_MULTI_ARCH
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
*************** repenting at leisure.
*** 1607,1613 ****
@item SYMBOLS_CAN_START_WITH_DOLLAR
Some systems have routines whose names start with @samp{$}. Giving this
! macro a non-zero value tells GDB's expression parser to check for such
routines when parsing tokens that begin with @samp{$}.
On HP-UX, certain system routines (millicode) have names beginning with
--- 1607,1613 ----
@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
*************** stepping will suffice.
*** 1665,1675 ****
@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
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
text section. (Seems dubious.)
@item NO_HIF_SUPPORT
--- 1665,1675 ----
@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 @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 @value{GDBN} should determine the start and end addresses of the
text section. (Seems dubious.)
@item NO_HIF_SUPPORT
*************** call. Return the updated stack pointer v
*** 1802,1808 ****
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
register state.
@item REGISTER_NAME(i)
--- 1802,1808 ----
Used in @samp{call_function_by_hand} to create an artificial stack frame.
@item REGISTER_BYTES
! The total amount of space needed to store @value{GDBN}'s copy of the machine's
register state.
@item REGISTER_NAME(i)
*************** This is the value of the @var{SP} after
*** 1823,1836 ****
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
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. GDB 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
--- 1823,1836 ----
for parameters/results have been allocated on the stack.
@item SDB_REG_TO_REGNUM
! Define this to convert sdb register numbers into @value{GDBN} regnums. If not
defined, no conversion will be done.
@item SHIFT_INST_REGS
(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
*************** This should only need to be defined if @
*** 1862,1868 ****
@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
done.
@item STACK_ALIGN (addr)
--- 1862,1868 ----
@item STAB_REG_TO_REGNUM
Define this to convert stab register numbers (as gotten from `r'
! declarations) into @value{GDBN} regnums. If not defined, no conversion will be
done.
@item STACK_ALIGN (addr)
*************** processor's stack.
*** 1872,1878 ****
@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
normally. Currently only defined for the Mips.
@item STORE_RETURN_VALUE (type, valbuf)
--- 1872,1878 ----
@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, @value{GDBN} will single-step over that instruction before resuming
normally. Currently only defined for the Mips.
@item STORE_RETURN_VALUE (type, valbuf)
*************** Number of bits in a short integer; defau
*** 1942,1948 ****
@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
and write register functions with the relevant @code{_REGNUM} argument.
These macros are useful when a target keeps one of these registers in a
--- 1942,1948 ----
@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. @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
*************** other compilers.
*** 1967,1973 ****
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
presence of either the @code{GCC_COMPILED_SYMBOL} or the
@code{GCC2_COMPILED_SYMBOL}. By default, this is 0.
--- 1967,1973 ----
For dbx-style debugging information, if the compiler puts variable
declarations inside LBRAC/RBRAC blocks, this should be defined to be
nonzero. @var{desc} is the value of @code{n_desc} from the
! @code{N_RBRAC} symbol, and @var{gcc_p} is true if @value{GDBN} has noticed the
presence of either the @code{GCC_COMPILED_SYMBOL} or the
@code{GCC2_COMPILED_SYMBOL}. By default, this is 0.
*************** Defaults to @code{1}.
*** 1991,1997 ****
@section Adding a New Target
! The following files define a target to GDB:
@table @file
--- 1991,1997 ----
@section Adding a New Target
! The following files define a target to @value{GDBN}:
@table @file
*************** tm-@var{ttt}.h}.
*** 2004,2010 ****
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 GDB.
@item gdb/config/@var{arch}/tm-@var{ttt}.h
(@file{tm.h} is a link to this file, created by configure). Contains
--- 2004,2010 ----
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
*************** that just @code{#include}s @file{tm-@var
*** 2043,2052 ****
@chapter Target Vector Definition
! The target vector defines the interface between GDB's abstract handling
of target systems, and the nitty-gritty code that actually exercises
! control over a process or a serial port. GDB includes some 30-40
! different target vectors; however, each configuration of GDB includes
only a few of them.
@section File Targets
--- 2043,2052 ----
@chapter Target Vector Definition
! The target vector defines the interface between @value{GDBN}'s abstract handling
of target systems, and the nitty-gritty code that actually exercises
! control over a process or a serial port. @value{GDBN} includes some 30-40
! different target vectors; however, each configuration of @value{GDBN} includes
only a few of them.
@section File Targets
*************** Both executables and core files have tar
*** 2055,2066 ****
@section Standard Protocol and Remote Stubs
! GDB's file @file{remote.c} talks a serial protocol to code that runs in
! the target system. GDB provides several sample ``stubs'' that can be
integrated into target programs or operating systems for this purpose;
they are named @file{*-stub.c}.
! The GDB user's manual describes how to put such a stub into your target
code. What follows is a discussion of integrating the SPARC stub into a
complicated operating system (rather than a simple program), by Stu
Grossman, the author of this stub.
--- 2055,2066 ----
@section Standard Protocol and Remote Stubs
! @value{GDBN}'s file @file{remote.c} talks a serial protocol to code that runs in
! the target system. @value{GDBN} provides several sample ``stubs'' that can be
integrated into target programs or operating systems for this purpose;
they are named @file{*-stub.c}.
! The @value{GDBN} user's manual describes how to put such a stub into your target
code. What follows is a discussion of integrating the SPARC stub into a
complicated operating system (rather than a simple program), by Stu
Grossman, the author of this stub.
*************** do breakpoints. Everything else is unne
*** 2095,2101 ****
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.
@section ROM Monitor Interface
--- 2095,2101 ----
of the debugger/stub.
From reading the stub, it's probably not obvious how breakpoints work.
! They are simply done by deposit/examine operations from @value{GDBN}.
@section ROM Monitor Interface
*************** They are simply done by deposit/examine
*** 2110,2116 ****
@chapter Native Debugging
! Several files control GDB's configuration for native support:
@table @file
--- 2110,2116 ----
@chapter Native Debugging
! Several files control @value{GDBN}'s configuration for native support:
@table @file
*************** just provide @code{fetch_core_registers}
*** 2179,2185 ****
@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
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
--- 2179,2185 ----
@item core-aout.c::register_addr()
If your @code{nm-@var{xyz}.h} file defines the macro
@code{REGISTER_U_ADDR(addr, blockend, regno)}, it should be defined to
! set @code{addr} to the offset within the @samp{user} struct of @value{GDBN}
register number @code{regno}. @code{blockend} is the offset within the
``upage'' of @code{u.u_ar0}. If @code{REGISTER_U_ADDR} is defined,
@file{core-aout.c} will define the @code{register_addr()} function and
*************** implementations simply locate the regist
*** 2194,2200 ****
@end table
! When making GDB run native on a new operating system, to make it
possible to debug core files, you will need to either write specific
code for parsing your OS's core files, or customize
@file{bfd/trad-core.c}. First, use whatever @code{#include} files your
--- 2194,2200 ----
@end table
! 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
*************** section information basically delimits a
*** 2211,2223 ****
standard way, which the section-reading routines in BFD know how to seek
around in.
! Then back in GDB, you need a matching routine called
@code{fetch_core_registers()}. If you can use the generic one, it's in
@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.
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
--- 2211,2223 ----
standard way, which the section-reading routines in BFD know how to seek
around in.
! Then back in @value{GDBN}, you need a matching routine called
@code{fetch_core_registers()}. If you can use the generic one, it's in
@file{core-aout.c}; if not, it's in your @file{@var{xyz}-nat.c} file.
It will be passed a char pointer to the entire ``registers'' segment,
its length, and a zero; or a char pointer to the entire ``regs2''
segment, its length, and a 2. The routine should suck out the supplied
! register values and install them into @value{GDBN}'s ``registers'' array.
If your system uses @file{/proc} to control processes, and uses ELF
format core files, then you may be able to use the same routines for
*************** reading the registers out of processes a
*** 2233,2239 ****
@section Native Conditionals
! When GDB is configured and compiled, various macros are defined or left
undefined, to control compilation when the host and target systems are
the same. These macros should be defined (or left undefined) in
@file{nm-@var{system}.h}.
--- 2233,2239 ----
@section Native Conditionals
! When @value{GDBN} is configured and compiled, various macros are defined or left
undefined, to control compilation when the host and target systems are
the same. These macros should be defined (or left undefined) in
@file{nm-@var{system}.h}.
*************** the same. These macros should be define
*** 2241,2247 ****
@table @code
@item ATTACH_DETACH
! If defined, then GDB will include support for the @code{attach} and
@code{detach} commands.
@item CHILD_PREPARE_TO_STORE
--- 2241,2247 ----
@table @code
@item ATTACH_DETACH
! If defined, then @value{GDBN} will include support for the @code{attach} and
@code{detach} commands.
@item CHILD_PREPARE_TO_STORE
*************** pointer. It examines the current state
*** 2280,2297 ****
@item KERNEL_U_ADDR
Define this to the address of the @code{u} structure (the ``user
! struct'', also known as the ``u-page'') in kernel virtual memory. GDB
needs to know this so that it can subtract this address from absolute
addresses in the upage, that are obtained via ptrace or from core files.
On systems that don't need this value, set it to zero.
@item KERNEL_U_ADDR_BSD
! Define this to cause GDB to determine the address of @code{u} at
runtime, by using Berkeley-style @code{nlist} on the kernel's image in
the root directory.
@item KERNEL_U_ADDR_HPUX
! Define this to cause GDB to determine the address of @code{u} at
runtime, by using HP-style @code{nlist} on the kernel's image in the
root directory.
--- 2280,2297 ----
@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. @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 @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 @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.
*************** threads.
*** 2307,2313 ****
In a multi-threaded task we may select another thread and then continue
or step. But if the old thread was stopped at a breakpoint, it will
immediately cause another breakpoint stop without any execution (i.e. it
! will report a breakpoint hit incorrectly). So GDB must step over it
first.
If defined, @code{PREPARE_TO_PROCEED} should check the current thread
--- 2307,2313 ----
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
*************** Defaults to @code{"/bin/sh"}.
*** 2340,2353 ****
@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.
@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
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.
--- 2340,2353 ----
@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 @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, @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.
*************** Define this to indicate that SVR4-style
*** 2357,2363 ****
@item USE_PROC_FS
This determines whether small routines in @file{*-tdep.c}, which
! translate register values between GDB's internal representation and the
/proc representation, are compiled.
@item U_REGS_OFFSET
--- 2357,2363 ----
@item USE_PROC_FS
This determines whether small routines in @file{*-tdep.c}, which
! translate register values between @value{GDBN}'s internal representation and the
/proc representation, are compiled.
@item U_REGS_OFFSET
*************** Define this to debug ptrace calls.
*** 2387,2393 ****
@section BFD
! BFD provides support for GDB in several ways:
@table @emph
--- 2387,2393 ----
@section BFD
! BFD provides support for @value{GDBN} in several ways:
@table @emph
*************** several variants thereof, as well as sev
*** 2398,2404 ****
@item access to sections of files
BFD parses the file headers to determine the names, virtual addresses,
sizes, and file locations of all the various named sections in files
! (such as the text section or the data section). GDB simply calls BFD to
read or write section X at byte offset Y for length Z.
@item specialized core file support
--- 2398,2404 ----
@item access to sections of files
BFD parses the file headers to determine the names, virtual addresses,
sizes, and file locations of all the various named sections in files
! (such as the text section or the data section). @value{GDBN} simply calls BFD to
read or write section X at byte offset Y for length Z.
@item specialized core file support
*************** file matches (i.e. could be a core dump
*** 2408,2424 ****
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
handles the reading of symbols, since BFD does not ``understand'' debug
! symbols, but GDB uses BFD's cached information to find the symbols,
string table, etc.
@end table
@section opcodes
! The opcodes library provides GDB's disassembler. (It's a separate
library because it's also used in binutils, for @file{objdump}).
@section readline
--- 2408,2424 ----
file.
@item locating the symbol information
! @value{GDBN} uses an internal interface of BFD to determine where to find the
! symbol information in an executable file or symbol-file. @value{GDBN} itself
handles the reading of symbols, since BFD does not ``understand'' debug
! symbols, but @value{GDBN} uses BFD's cached information to find the symbols,
string table, etc.
@end table
@section opcodes
! 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
*************** Regex conditionals.
*** 2458,2464 ****
@chapter Coding
This chapter covers topics that are lower-level than the major
! algorithms of GDB.
@section Cleanups
--- 2458,2464 ----
@chapter Coding
This chapter covers topics that are lower-level than the major
! algorithms of @value{GDBN}.
@section Cleanups
*************** finish by printing a newline, to flush t
*** 2538,2556 ****
to unfiltered (``@code{printf}'') output. Symbol reading routines that
print warnings are a good example.
! @section GDB Coding Standards
! GDB follows the GNU coding standards, as described in
@file{etc/standards.texi}. This file is also available for anonymous
! FTP from GNU archive sites. GDB takes a strict interpretation of the
standard; in general, when the GNU standard recommends a practice but
! does not require it, GDB requires it.
! GDB follows an additional set of coding standards specific to GDB,
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}.
--- 2538,2556 ----
to unfiltered (``@code{printf}'') output. Symbol reading routines that
print warnings are a good example.
! @section @value{GDBN} Coding Standards
! @value{GDBN} follows the GNU coding standards, as described in
@file{etc/standards.texi}. This file is also available for anonymous
! FTP from GNU archive sites. @value{GDBN} takes a strict interpretation of the
standard; in general, when the GNU standard recommends a practice but
! does not require it, @value{GDBN} requires it.
! @value{GDBN} follows an additional set of coding standards specific to @value{GDBN},
as described in the following sections.
You can configure with @samp{--enable-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{-Wall -Wpointer-arith
-Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations}.
*************** Block comments must appear in the follow
*** 2587,2593 ****
gets a signal, we may decide to start it up again instead of
returning. That is why there is a loop in this function. When
this function actually returns it means the inferior should be left
! stopped and GDB should read more commands. */
@end example
(Note that this format is encouraged by Emacs; tabbing for a multi-line
--- 2587,2593 ----
gets a signal, we may decide to start it up again instead of
returning. That is why there is a loop in this function. When
this function actually returns it means the inferior should be left
! stopped and @value{GDBN} should read more commands. */
@end example
(Note that this format is encouraged by Emacs; tabbing for a multi-line
*************** host's floating point numbers, the align
*** 2608,2615 ****
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
interface (whether serial line or system call).
However, use functions with moderation. A thousand one-line functions
--- 2608,2615 ----
of evaluation of expressions.
Use functions freely. There are only a handful of compute-bound areas
! in @value{GDBN} that might be affected by the overhead of a function call, mainly
! in symbol reading. Most of @value{GDBN}'s performance is limited by the target
interface (whether serial line or system call).
However, use functions with moderation. A thousand one-line functions
*************** are just as hard to understand as a sing
*** 2618,2624 ****
@subsection Function Prototypes
Prototypes must be used to @emph{declare} functions, and may be used to
! @emph{define} them. Prototypes for GDB functions must include both the
argument type and name, with the name matching that used in the actual
function definition.
--- 2618,2624 ----
@subsection Function Prototypes
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.
*************** source file.
*** 2633,2645 ****
@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
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
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
--- 2633,2645 ----
@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 @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 @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
*************** where the macro is used or in an appropr
*** 2698,2704 ****
Whether to include a @dfn{small} hook, a hook around the exact pieces of
code which are system-dependent, or whether to replace a whole function
with a hook depends on the case. A good example of this dilemma can be
! found in @code{get_saved_register}. All machines that GDB 2.8 ran on
just needed the @code{FRAME_FIND_SAVED_REGS} hook to find the saved
registers. Then the SPARC and Pyramid came along, and
@code{HAVE_REGISTER_WINDOWS} and @code{REGISTER_IN_WINDOW_P} were
--- 2698,2704 ----
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 @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
*************** with @code{GET_SAVED_REGISTER}, since th
*** 2710,2717 ****
duplicated code. Other times, duplicating a few lines of code here or
there is much cleaner than introducing a large number of small hooks.
! Another way to generalize GDB along a particular interface is with an
! attribute struct. For example, GDB has been generalized to handle
multiple kinds of remote interfaces -- not by #ifdef's everywhere, but
by defining the "target_ops" structure and having a current target (as
well as a stack of targets below it, for memory references). Whenever
--- 2710,2717 ----
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 @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
*************** current target_ops structure. In this w
*** 2722,2732 ****
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.
! Please avoid duplicating code. For example, in GDB 3.x all the code
! interfacing between @code{ptrace} and the rest of GDB was duplicated in
! @file{*-dep.c}, and so changing something was very painful. In GDB 4.x,
these have all been consolidated into @file{infptrace.c}.
@file{infptrace.c} can deal with variations between systems the same way
any system-independent file would (hooks, #if defined, etc.), and
--- 2722,2732 ----
is added, only one module needs to be touched -- the one that actually
implements the new remote interface. Other examples of
attribute-structs are BFD access to multiple kinds of object file
! formats, or @value{GDBN}'s access to multiple source languages.
! Please avoid duplicating code. For example, in @value{GDBN} 3.x all the code
! interfacing between @code{ptrace} and the rest of @value{GDBN} was duplicated in
! @file{*-dep.c}, and so changing something was very painful. In @value{GDBN} 4.x,
these have all been consolidated into @file{infptrace.c}.
@file{infptrace.c} can deal with variations between systems the same way
any system-independent file would (hooks, #if defined, etc.), and
*************** all.
*** 2735,2745 ****
Don't put debugging printfs in the code.
! @node Porting GDB
! @chapter Porting GDB
! Most of the work in making GDB compile on a new machine is in specifying
the configuration of the machine. This is done in a dizzying variety of
header files and configuration scripts, which we hope to make more
sensible soon. Let's say your new host is called an @var{xyz} (e.g.
--- 2735,2745 ----
Don't put debugging printfs in the code.
! @node Porting @value{GDBN}
! @chapter Porting @value{GDBN}
! 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.
*************** and no error messages.
*** 2769,2785 ****
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
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
target-dependent @file{.h} and @file{.c} files used for your
configuration.
! @section Configuring GDB for Release
From the top level directory (containing @file{gdb}, @file{bfd},
@file{libiberty}, and so on):
--- 2769,2785 ----
You need to port BFD, if that hasn't been done already. Porting BFD is
beyond the scope of this manual.
! 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 @value{GDBN}'s host-, native-, and
target-dependent @file{.h} and @file{.c} files used for your
configuration.
! @section Configuring @value{GDBN} for Release
From the top level directory (containing @file{gdb}, @file{bfd},
@file{libiberty}, and so on):
*************** or so included files.
*** 2822,2841 ****
@chapter Testsuite
! The testsuite is an important component of the GDB package. While it is
always worthwhile to encourage user testing, in practice this is rarely
sufficient; users typically use only a small subset of the available
commands, and it has proven all too common for a change to cause a
significant regression that went unnoticed for some time.
! The GDB testsuite uses the DejaGNU testing framework. DejaGNU is built
using tcl and expect. The tests themselves are calls to various tcl
procs; the framework runs all the procs and summarizes the passes and
fails.
@section Using the Testsuite
! To run the testsuite, simply go to the GDB 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,
--- 2822,2841 ----
@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,
*************** finished, you'll get a summary that look
*** 2853,2869 ****
@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 GDB or in the testsuite. Expected failures
are still failures, but ones which have been decided are too hard to
deal with at the time; for instance, a test case might work everywhere
except on AIX, and there is no prospect of the AIX case being fixed in
the near future. Expected failures should not be added lightly, since
! you may be masking serious bugs in GDB. Unexpected successes are expected
fails that are passing for some reason, while unresolved and untested
cases often indicate some minor catastrophe, such as the compiler being
unable to deal with a test program.
! When making any significant change to GDB, you should run the testsuite
before and after the change, to confirm that there are no regressions.
Note that truly complete testing would require that you run the
testsuite with all supported configurations and a variety of compilers;
--- 2853,2869 ----
@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;
*************** one big-endian (Sparc) and one little-en
*** 2873,2880 ****
with a builtin simulator (powerpc-eabi, mips-elf), or a 64-bit host
(Alpha).
! If you add new functionality to GDB, please consider adding tests for it
! as well; this way future GDB hackers can detect and fix their changes
that break the functionality you added. Similarly, if you fix a bug
that was not previously reported as a test failure, please add a test
case for it. Some cases are extremely difficult to test, such as code
--- 2873,2880 ----
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
*************** compilers, and it's OK not to try to wri
*** 2886,2894 ****
The testsuite is entirely contained in @file{gdb/testsuite}. While the
testsuite includes some makefiles and configury, these are very minimal,
and used for little besides cleaning up, since the tests themselves
! handle the compilation of the programs that GDB will run. The file
@file{testsuite/lib/gdb.exp} contains common utility procs useful for
! all GDB 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}.
--- 2886,2894 ----
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}.
*************** intelligibility.
*** 2909,2915 ****
@item gdb.base
This is the base testsuite. The tests in it should apply to all
! configurations of GDB (but generic native-only tests may live here).
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).
--- 2909,2915 ----
@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).
*************** HP-UX.
*** 2930,2940 ****
Tests specific to a particular compiler. As of this writing (June
1999), there aren't currently any groups of tests in this category that
couldn't just as sensibly be made platform-specific, but one could
! imagine a gdb.gcc, for tests of GDB's handling of GCC extensions.
@item gdb.@var{subsystem}
! Tests that exercise a specific GDB subsystem in more depth. For
instance, @file{gdb.disasm} exercises various disassemblers, while
@file{gdb.stabs} tests pathways through the stabs symbol reader.
--- 2930,2940 ----
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.
*************** instance, @file{gdb.disasm} exercises va
*** 2942,2948 ****
@section Writing Tests
! In many areas, the GDB 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
--- 2942,2948 ----
@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
*************** instance, @file{gdb.base/exprs.exp} defi
*** 2952,2963 ****
calls @code{gdb_test} multiple times.
Only use @code{send_gdb} and @code{gdb_expect} when absolutely
! necessary, such as when GDB has several valid responses to a command.
The source language programs do @emph{not} need to be in a consistent
! style. Since GDB is used to debug programs written in many different
styles, it's worth having a mix of styles in the testsuite; for
! instance, some GDB bugs involving the display of source lines would
never manifest themselves if the programs used GNU coding style
uniformly.
--- 2952,2963 ----
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.
*************** Check the @file{README} file, it often h
*** 2969,2993 ****
appear anywhere else in the directory.
@menu
! * Getting Started:: Getting started working on GDB
! * Debugging GDB:: Debugging GDB with itself
@end menu
@node Getting Started,,, Hints
@section Getting Started
! GDB is a large and complicated program, and if you first starting to
work on it, it can be hard to know where to start. Fortunately, if you
know how to go about it, there are ways to figure out what is going on.
! This manual, the GDB Internals manual, has information which applies
! generally to many parts of GDB.
Information about particular functions or data structures are located in
comments with those functions or data structures. If you run across a
function or a global variable which does not have a comment correctly
! explaining what is does, this can be thought of as a bug in GDB; feel
free to submit a bug report, with a suggested comment if you can figure
out what the comment should say. If you find a comment which is
actually wrong, be especially sure to report that.
--- 2969,2993 ----
appear anywhere else in the directory.
@menu
! * Getting Started:: Getting started working on @value{GDBN}
! * Debugging @value{GDBN}:: Debugging @value{GDBN} with itself
@end menu
@node Getting Started,,, Hints
@section Getting Started
! @value{GDBN} is a large and complicated program, and if you first starting to
work on it, it can be hard to know where to start. Fortunately, if you
know how to go about it, there are ways to figure out what is going on.
! This manual, the @value{GDBN} Internals manual, has information which applies
! generally to many parts of @value{GDBN}.
Information about particular functions or data structures are located in
comments with those functions or data structures. If you run across a
function or a global variable which does not have a comment correctly
! explaining what is does, this can be thought of as a bug in @value{GDBN}; feel
free to submit a bug report, with a suggested comment if you can figure
out what the comment should say. If you find a comment which is
actually wrong, be especially sure to report that.
*************** also documents all the available macros.
*** 3002,3021 ****
@c Conditionals}, @pxref{Native Conditionals}, and @pxref{Obsolete
@c Conditionals})
! Start with the header files. Once you have some idea of how GDB's internal
symbol tables are stored (see @file{symtab.h}, @file{gdbtypes.h}), you
will find it much easier to understand the code which uses and creates
those symbol tables.
You may wish to process the information you are getting somehow, to
enhance your understanding of it. Summarize it, translate it to another
! language, add some (perhaps trivial or non-useful) feature to GDB, use
the code to predict what a test case would do and write the test case
and verify your prediction, etc. If you are reading code and your eyes
are starting to glaze over, this is a sign you need to use a more active
approach.
! Once you have a part of GDB to start with, you can find more
specifically the part you are looking for by stepping through each
function with the @code{next} command. Do not use @code{step} or you
will quickly get distracted; when the function you are stepping through
--- 3002,3021 ----
@c Conditionals}, @pxref{Native Conditionals}, and @pxref{Obsolete
@c Conditionals})
! Start with the header files. Once you have some idea of how @value{GDBN}'s internal
symbol tables are stored (see @file{symtab.h}, @file{gdbtypes.h}), you
will find it much easier to understand the code which uses and creates
those symbol tables.
You may wish to process the information you are getting somehow, to
enhance your understanding of it. Summarize it, translate it to another
! language, add some (perhaps trivial or non-useful) feature to @value{GDBN}, use
the code to predict what a test case would do and write the test case
and verify your prediction, etc. If you are reading code and your eyes
are starting to glaze over, this is a sign you need to use a more active
approach.
! Once you have a part of @value{GDBN} to start with, you can find more
specifically the part you are looking for by stepping through each
function with the @code{next} command. Do not use @code{step} or you
will quickly get distracted; when the function you are stepping through
*************** rather than worrying about all its detai
*** 3036,3042 ****
A good place to start when tracking down some particular area is with a
command which invokes that feature. Suppose you want to know how
! single-stepping works. As a GDB user, you know that the @code{step}
command invokes single-stepping. The command is invoked via command
tables (see @file{command.h}); by convention the function which actually
performs the command is formed by taking the name of the command and
--- 3036,3042 ----
A good place to start when tracking down some particular area is with a
command which invokes that feature. Suppose you want to know how
! single-stepping works. As a @value{GDBN} user, you know that the @code{step}
command invokes single-stepping. The command is invoked via command
tables (see @file{command.h}); by convention the function which actually
performs the command is formed by taking the name of the command and
*************** adding @samp{_command}, or in the case o
*** 3044,3073 ****
@samp{_info}. For example, the @code{step} command invokes the
@code{step_command} function and the @code{info display} command invokes
@code{display_info}. When this convention is not followed, you might
! have to use @code{grep} or @kbd{M-x tags-search} in emacs, or run GDB on
itself and set a breakpoint in @code{execute_command}.
If all of the above fail, it may be appropriate to ask for information
on @code{bug-gdb}. But @emph{never} post a generic question like ``I was
wondering if anyone could give me some tips about understanding
! GDB''---if we had some magic secret we would put it in this manual.
Suggestions for improving the manual are always welcome, of course.
! @node Debugging GDB,,,Hints
! @section Debugging GDB with itself
! If GDB is limping on your machine, this is the preferred way to get it
fully functional. Be warned that in some ancient Unix systems, like
Ultrix 4.2, 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
@file{.gdbinit} file that sets up some simple things to make debugging
gdb easier. The @code{info} command, when executed without a subcommand
! in a GDB being debugged by gdb, will pop you back up to the top level
gdb. See @file{.gdbinit} for details.
If you use emacs, you will probably want to do a @code{make TAGS} after
--- 3044,3073 ----
@samp{_info}. For example, the @code{step} command invokes the
@code{step_command} function and the @code{info display} command invokes
@code{display_info}. When this convention is not followed, you might
! have to use @code{grep} or @kbd{M-x tags-search} in emacs, or run @value{GDBN} on
itself and set a breakpoint in @code{execute_command}.
If all of the above fail, it may be appropriate to ask for information
on @code{bug-gdb}. But @emph{never} post a generic question like ``I was
wondering if anyone could give me some tips about understanding
! @value{GDBN}''---if we had some magic secret we would put it in this manual.
Suggestions for improving the manual are always welcome, of course.
! @node Debugging @value{GDBN},,,Hints
! @section Debugging @value{GDBN} with itself
! 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 @value{GDBN} in the @value{GDBN} source directory, it will read a
@file{.gdbinit} file that sets up some simple things to make debugging
gdb easier. The @code{info} command, when executed without a subcommand
! in a @value{GDBN} being debugged by gdb, will pop you back up to the top level
gdb. See @file{.gdbinit} for details.
If you use emacs, you will probably want to do a @code{make TAGS} after
*************** you configure your distribution; this wi
*** 3075,3092 ****
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
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.
Thanks also for checking in advance about the best way to transfer the
changes.
! The GDB maintainers will only install ``cleanly designed'' patches.
! This manual summarizes what we believe to be clean design for GDB.
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
--- 3075,3092 ----
routines for your local machine where they will be accessed first by
@kbd{M-.}
! Also, make sure that you've either compiled @value{GDBN} with your local cc, or
have run @code{fixincludes} if you are compiling with gcc.
@section Submitting Patches
Thanks for thinking of offering your changes back to the community of
! @value{GDBN} users. In general we like to get well designed enhancements.
Thanks also for checking in advance about the best way to transfer the
changes.
! The @value{GDBN} maintainers will only install ``cleanly designed'' patches.
! This manual summarizes what we believe to be clean design for @value{GDBN}.
If the maintainers don't have time to put the patch in when it arrives,
or if there is any question about a patch, it goes into a large queue
*************** of the changes to the Free Software Foun
*** 3098,3104 ****
standard documents for doing this by sending mail to @code{gnu@@gnu.org}
and asking for it. We recommend that people write in "All programs
owned by the Free Software Foundation" as "NAME OF PROGRAM", so that
! changes in many programs (not just GDB, but GAS, Emacs, GCC, etc) can be
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
--- 3098,3104 ----
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
*************** they arrive. The others go into a queue
*** 3138,3149 ****
permits, which, since the maintainers have many demands to meet, may not
be for quite some time.
! Please send patches directly to the GDB maintainers at
@code{gdb-patches@@sourceware.cygnus.com}.
@section Obsolete Conditionals
! Fragments of old code in GDB sometimes reference or set the following
configuration macros. They should not be used by new code, and old uses
should be removed as those parts of the debugger are otherwise touched.
--- 3138,3149 ----
permits, which, since the maintainers have many demands to meet, may not
be for quite some time.
! Please send patches directly to the @value{GDBN} maintainers at
@code{gdb-patches@@sourceware.cygnus.com}.
@section Obsolete Conditionals
! 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.
*************** should be removed as those parts of the
*** 3152,3161 ****
@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
files should be moved into BFD configuration files (if needed there),
! and deleted from all of GDB'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!
--- 3152,3161 ----
@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 @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 @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!