blob: b28182417541e8c14cc0041741061682b70af466 [file] [log] [blame]
What has changed in GDB?
(Organized release by release)
*** Changes in GDB 7.5
* GDB now supports x32 ABI. Visit <>
for more x32 ABI info.
* GDB now supports access to MIPS DSP registers on Linux targets.
* GDB now supports debugging microMIPS binaries.
* The "info os" command on GNU/Linux can now display information on
several new classes of objects managed by the operating system:
"info os procgroups" lists process groups
"info os files" lists file descriptors
"info os sockets" lists internet-domain sockets
"info os shm" lists shared-memory regions
"info os semaphores" lists semaphores
"info os msg" lists message queues
"info os modules" lists loaded kernel modules
* GDB now has support for SDT (Static Defined Tracing) probes. Currently,
the only implemented backend is for SystemTap probes (<sys/sdt.h>). You
can set a breakpoint using the new "-probe, "-pstap" or "-probe-stap"
options and inspect the probe arguments using the new $_probe_arg family
of convenience variables. You can obtain more information about SystemTap
in <>.
* GDB now supports reversible debugging on ARM, it allows you to
debug basic ARM and THUMB instructions, and provides
record/replay support.
* The option "symbol-reloading" has been deleted as it is no longer used.
* Python scripting
** GDB commands implemented in Python can now be put in command class
** The "maint set python print-stack on|off" is now deleted.
** A new class, gdb.printing.FlagEnumerationPrinter, can be used to
apply "flag enum"-style pretty-printing to any enum.
** gdb.lookup_symbol can now work when there is no current frame.
** gdb.Symbol now has a 'line' attribute, holding the line number in
the source at which the symbol was defined.
** gdb.Symbol now has the new attribute 'needs_frame' and the new
method 'value'. The former indicates whether the symbol needs a
frame in order to compute its value, and the latter computes the
symbol's value.
** A new method 'referenced_value' on gdb.Value objects which can
dereference pointer as well as C++ reference values.
** New methods 'global_block' and 'static_block' on gdb.Symtab objects
which return the global and static blocks (as gdb.Block objects),
of the underlying symbol table, respectively.
** New function gdb.find_pc_line which returns the gdb.Symtab_and_line
object associated with a PC value.
** gdb.Symtab_and_line has new attribute 'last' which holds the end
of the address range occupied by code for the current source line.
* Go language support.
GDB now supports debugging programs written in the Go programming
* GDBserver now supports stdio connections.
E.g. (gdb) target remote | ssh myhost gdbserver - hello
* The binary "gdbtui" can no longer be built or installed.
Use "gdb -tui" instead.
* GDB will now print "flag" enums specially. A flag enum is one where
all the enumerator values have no bits in common when pairwise
"and"ed. When printing a value whose type is a flag enum, GDB will
show all the constants, e.g., for enum E { ONE = 1, TWO = 2}:
(gdb) print (enum E) 3
$1 = (ONE | TWO)
* The filename part of a linespec will now match trailing components
of a source file name. For example, "break gcc/expr.c:1000" will
now set a breakpoint in build/gcc/expr.c, but not
* The "info proc" and "generate-core-file" commands will now also
work on remote targets connected to GDBserver on Linux.
* The command "info catch" has been removed. It has been disabled
since December 2007.
* The "catch exception" and "catch assert" commands now accept
a condition at the end of the command, much like the "break"
command does. For instance:
(gdb) catch exception Constraint_Error if Barrier = True
Previously, it was possible to add a condition to such catchpoints,
but it had to be done as a second step, after the catchpoint had been
created, using the "condition" command.
* The "info static-tracepoint-marker" command will now also work on
native Linux targets with in-process agent.
* GDB can now set breakpoints on inlined functions.
* The .gdb_index section has been updated to include symbols for
inlined functions. GDB will ignore older .gdb_index sections by
default, which could cause symbol files to be loaded more slowly
until their .gdb_index sections can be recreated. The new command
"set use-deprecated-index-sections on" will cause GDB to use any older
.gdb_index sections it finds. This will restore performance, but the
ability to set breakpoints on inlined functions will be lost in symbol
files with older .gdb_index sections.
The .gdb_index section has also been updated to record more information
about each symbol. This speeds up the "info variables", "info functions"
and "info types" commands when used with programs having the .gdb_index
section, as well as speeding up debugging with shared libraries using
the .gdb_index section.
* Ada support for GDB/MI Variable Objects has been added.
* GDB can now support 'breakpoint always-inserted mode' in 'record'
* MI changes
** New command -info-os is the MI equivalent of "info os".
** Output logs ("set logging" and related) now include MI output.
* New commands
** "set use-deprecated-index-sections on|off"
"show use-deprecated-index-sections on|off"
Controls the use of deprecated .gdb_index sections.
** "catch load" and "catch unload" can be used to stop when a shared
library is loaded or unloaded, respectively.
** "enable count" can be used to auto-disable a breakpoint after
several hits.
** "info vtbl" can be used to show the virtual method tables for
C++ and Java objects.
** "explore" and its sub commands "explore value" and "explore type"
can be used to reccursively explore values and types of
expressions. These commands are available only if GDB is
configured with '--with-python'.
** "info auto-load" shows status of all kinds of auto-loaded files,
"info auto-load gdb-scripts" shows status of auto-loading GDB canned
sequences of commands files, "info auto-load python-scripts"
shows status of auto-loading Python script files,
"info auto-load local-gdbinit" shows status of loading init file
(.gdbinit) from current directory and "info auto-load libthread-db" shows
status of inferior specific thread debugging shared library loading.
** "info auto-load-scripts", "set auto-load-scripts on|off"
and "show auto-load-scripts" commands have been deprecated, use their
"info auto-load python-scripts", "set auto-load python-scripts on|off"
and "show auto-load python-scripts" counterparts instead.
** "dprintf location,format,args..." creates a dynamic printf, which
is basically a breakpoint that does a printf and immediately
resumes your program's execution, so it is like a printf that you
can insert dynamically at runtime instead of at compiletime.
** "set print symbol"
"show print symbol"
Controls whether GDB attempts to display the symbol, if any,
corresponding to addresses it prints. This defaults to "on", but
you can set it to "off" to restore GDB's previous behavior.
* Deprecated commands
** For the Renesas Super-H architecture, the "regs" command has been
deprecated, and "info all-registers" should be used instead.
* New targets
Renesas RL78 rl78-*-elf
HP OpenVMS ia64 ia64-hp-openvms*
* GDBserver supports evaluation of breakpoint conditions. When
support is advertised by GDBserver, GDB may be told to send the
breakpoint conditions in bytecode form to GDBserver. GDBserver
will only report the breakpoint trigger to GDB when its condition
evaluates to true.
* New options
set mips compression
show mips compression
Select the compressed ISA encoding used in functions that have no symbol
information available. The encoding can be set to either of:
and is updated automatically from ELF file flags if available.
set breakpoint condition-evaluation
show breakpoint condition-evaluation
Control whether breakpoint conditions are evaluated by GDB ("host") or by
GDBserver ("target"). Default option "auto" chooses the most efficient
available mode.
This option can improve debugger efficiency depending on the speed of the
set auto-load off
Disable auto-loading globally.
show auto-load
Show auto-loading setting of all kinds of auto-loaded files.
set auto-load gdb-scripts on|off
show auto-load gdb-scripts
Control auto-loading of GDB canned sequences of commands files.
set auto-load python-scripts on|off
show auto-load python-scripts
Control auto-loading of Python script files.
set auto-load local-gdbinit on|off
show auto-load local-gdbinit
Control loading of init file (.gdbinit) from current directory.
set auto-load libthread-db on|off
show auto-load libthread-db
Control auto-loading of inferior specific thread debugging shared library.
set auto-load scripts-directory <dir1>[:<dir2>...]
show auto-load scripts-directory
Set a list of directories from which to load auto-loaded scripts.
Automatically loaded Python scripts and GDB scripts are located in one
of the directories listed by this option.
The delimiter (':' above) may differ according to the host platform.
set auto-load safe-path <dir1>[:<dir2>...]
show auto-load safe-path
Set a list of directories from which it is safe to auto-load files.
The delimiter (':' above) may differ according to the host platform.
set debug auto-load on|off
show debug auto-load
Control display of debugging info for auto-loading the files above.
set dprintf-style gdb|call|agent
show dprintf-style
Control the way in which a dynamic printf is performed; "gdb"
requests a GDB printf command, while "call" causes dprintf to call a
function in the inferior. "agent" requests that the target agent
(such as GDBserver) do the printing.
set dprintf-function <expr>
show dprintf-function
set dprintf-channel <expr>
show dprintf-channel
Set the function and optional first argument to the call when using
the "call" style of dynamic printf.
set disconnected-dprintf on|off
show disconnected-dprintf
Control whether agent-style dynamic printfs continue to be in effect
after GDB disconnects.
* New configure options
Configure default value for the 'set auto-load scripts-directory'
setting above. It defaults to '$debugdir:$datadir/auto-load',
$debugdir representing global debugging info directories (available
via 'show debug-file-directory') and $datadir representing GDB's data
directory (available via 'show data-directory').
Configure default value for the 'set auto-load safe-path' setting
above. It defaults to the --with-auto-load-dir setting.
Set 'set auto-load safe-path' to '/', effectively disabling this
security feature.
* New remote packets
z0/z1 conditional breakpoints extension
The z0/z1 breakpoint insertion packets have been extended to carry
a list of conditional expressions over to the remote stub depending on the
condition evaluation mode. The use of this extension can be controlled
via the "set remote conditional-breakpoints-packet" command.
Specify the signals which the remote stub may pass to the debugged
program without GDB involvement.
* New command line options
--init-command=FILE, -ix Like --command, -x but execute it
before loading inferior.
--init-eval-command=COMMAND, -iex Like --eval-command=COMMAND, -ex but
execute it before loading inferior.
*** Changes in GDB 7.4
* GDB now handles ambiguous linespecs more consistently; the existing
FILE:LINE support has been expanded to other types of linespecs. A
breakpoint will now be set on all matching locations in all
inferiors, and locations will be added or removed according to
inferior changes.
* GDB now allows you to skip uninteresting functions and files when
stepping with the "skip function" and "skip file" commands.
* GDB has two new commands: "set remote hardware-watchpoint-length-limit"
and "show remote hardware-watchpoint-length-limit". These allows to
set or show the maximum length limit (in bytes) of a remote
target hardware watchpoint.
This allows e.g. to use "unlimited" hardware watchpoints with the
gdbserver integrated in Valgrind version >= 3.7.0. Such Valgrind
watchpoints are slower than real hardware watchpoints but are
significantly faster than gdb software watchpoints.
* Python scripting
** The register_pretty_printer function in module gdb.printing now takes
an optional `replace' argument. If True, the new printer replaces any
existing one.
** The "maint set python print-stack on|off" command has been
deprecated and will be deleted in GDB 7.5.
A new command: "set python print-stack none|full|message" has
replaced it. Additionally, the default for "print-stack" is
now "message", which just prints the error message without
the stack trace.
** A prompt substitution hook (prompt_hook) is now available to the
Python API.
** A new Python module, gdb.prompt has been added to the GDB Python
modules library. This module provides functionality for
escape sequences in prompts (used by set/show
extended-prompt). These escape sequences are replaced by their
corresponding value.
** Python commands and convenience-functions located in
'data-directory'/python/gdb/command and
'data-directory'/python/gdb/function are now automatically loaded
on GDB start-up.
** Blocks now provide four new attributes. global_block and
static_block will return the global and static blocks
respectively. is_static and is_global are boolean attributes
that indicate if the block is one of those two types.
** Symbols now provide the "type" attribute, the type of the symbol.
** The "gdb.breakpoint" function has been deprecated in favor of
** A new class "gdb.FinishBreakpoint" is provided to catch the return
of a function. This class is based on the "finish" command
available in the CLI.
** Type objects for struct and union types now allow access to
the fields using standard Python dictionary (mapping) methods.
For example, "some_type['myfield']" now works, as does
** A new event "gdb.new_objfile" has been added, triggered by loading a
new object file.
** A new function, "deep_items" has been added to the gdb.types
module in the GDB Python modules library. This function returns
an iterator over the fields of a struct or union type. Unlike
the standard Python "iteritems" method, it will recursively traverse
any anonymous fields.
* MI changes
** "*stopped" events can report several new "reason"s, such as
** Breakpoint changes are now notified using new async records, like
** New command -ada-task-info.
* libthread-db-search-path now supports two special values: $sdir and $pdir.
$sdir specifies the default system locations of shared libraries.
$pdir specifies the directory where the libpthread used by the application
GDB no longer looks in $sdir and $pdir after it has searched the directories
mentioned in libthread-db-search-path. If you want to search those
directories, they must be specified in libthread-db-search-path.
The default value of libthread-db-search-path on GNU/Linux and Solaris
systems is now "$sdir:$pdir".
$pdir is not supported by gdbserver, it is currently ignored.
$sdir is supported by gdbserver.
* New configure option --with-iconv-bin.
When using the internationalization support like the one in the GNU C
library, GDB will invoke the "iconv" program to get a list of supported
character sets. If this program lives in a non-standard location, one can
use this option to specify where to find it.
* When natively debugging programs on PowerPC BookE processors running
a Linux kernel version 2.6.34 or later, GDB supports masked hardware
watchpoints, which specify a mask in addition to an address to watch.
The mask specifies that some bits of an address (the bits which are
reset in the mask) should be ignored when matching the address accessed
by the inferior against the watchpoint address. See the "PowerPC Embedded"
section in the user manual for more details.
* The new option --once causes GDBserver to stop listening for connections once
the first connection is made. The listening port used by GDBserver will
become available after that.
* New commands "info macros" and "alias" have been added.
* New function parameters suffix @entry specifies value of function parameter
at the time the function got called. Entry values are available only since
gcc version 4.7.
* New commands
"!" is now an alias of the "shell" command.
Note that no space is needed between "!" and SHELL COMMAND.
* Changed commands
The watch command now supports the mask argument which allows creation
of masked watchpoints, if the current architecture supports this feature.
info auto-load-scripts [REGEXP]
This command was formerly named "maintenance print section-scripts".
It is now generally useful and is no longer a maintenance-only command.
info macro [-all] [--] MACRO
The info macro command has new options `-all' and `--'. The first for
printing all definitions of a macro. The second for explicitly specifying
the end of arguments and the beginning of the macro name in case the macro
name starts with a hyphen.
collect[/s] EXPRESSIONS
The tracepoint collect command now takes an optional modifier "/s"
that directs it to dereference pointer-to-character types and
collect the bytes of memory up to a zero byte. The behavior is
similar to what you see when you use the regular print command on a
string. An optional integer following the "/s" sets a bound on the
number of bytes that will be collected.
tstart [NOTES]
The trace start command now interprets any supplied arguments as a
note to be recorded with the trace run, with an effect similar to
setting the variable trace-notes.
tstop [NOTES]
The trace stop command now interprets any arguments as a note to be
mentioned along with the tstatus report that the trace was stopped
with a command. The effect is similar to setting the variable
* Tracepoints can now be enabled and disabled at any time after a trace
experiment has been started using the standard "enable" and "disable"
commands. It is now possible to start a trace experiment with no enabled
tracepoints; GDB will display a warning, but will allow the experiment to
begin, assuming that tracepoints will be enabled as needed while the trace
is running.
* Fast tracepoints on 32-bit x86-architectures can now be placed at
locations with 4-byte instructions, when they were previously
limited to locations with instructions of 5 bytes or longer.
* New options
set debug dwarf2-read
show debug dwarf2-read
Turns on or off display of debugging messages related to reading
DWARF debug info. The default is off.
set debug symtab-create
show debug symtab-create
Turns on or off display of debugging messages related to symbol table
creation. The default is off.
set extended-prompt
show extended-prompt
Set the GDB prompt, and allow escape sequences to be inserted to
display miscellaneous information (see 'help set extended-prompt'
for the list of sequences). This prompt (and any information
accessed through the escape sequences) is updated every time the
prompt is displayed.
set print entry-values (both|compact|default|if-needed|no|only|preferred)
show print entry-values
Set printing of frame argument values at function entry. In some cases
GDB can determine the value of function argument which was passed by the
function caller, even if the value was modified inside the called function.
set debug entry-values
show debug entry-values
Control display of debugging info for determining frame argument values at
function entry and virtual tail call frames.
set basenames-may-differ
show basenames-may-differ
Set whether a source file may have multiple base names.
(A "base name" is the name of a file with the directory part removed.
Example: The base name of "/home/user/hello.c" is "hello.c".)
If set, GDB will canonicalize file names (e.g., expand symlinks)
before comparing them. Canonicalization is an expensive operation,
but it allows the same file be known by more than one base name.
If not set (the default), all source files are assumed to have just
one base name, and gdb will do file name comparisons more efficiently.
set trace-user
show trace-user
set trace-notes
show trace-notes
Set a user name and notes for the current and any future trace runs.
This is useful for long-running and/or disconnected traces, to
inform others (or yourself) as to who is running the trace, supply
contact information, or otherwise explain what is going on.
set trace-stop-notes
show trace-stop-notes
Set a note attached to the trace run, that is displayed when the
trace has been stopped by a tstop command. This is useful for
instance as an explanation, if you are stopping a trace run that was
started by someone else.
* New remote packets
Dynamically enable a tracepoint in a started trace experiment.
Dynamically disable a tracepoint in a started trace experiment.
Set the user and notes of the trace run.
Query the current status of a tracepoint.
Query the minimum length of instruction at which a fast tracepoint may
be placed.
* Dcache size (number of lines) and line-size are now runtime-configurable
via "set dcache line" and "set dcache line-size" commands.
* New targets
Texas Instruments TMS320C6x tic6x-*-*
* New Simulators
Renesas RL78 rl78-*-elf
*** Changes in GDB 7.3.1
* The build failure for NetBSD and OpenBSD targets have now been fixed.
*** Changes in GDB 7.3
* GDB has a new command: "thread find [REGEXP]".
It finds the thread id whose name, target id, or thread extra info
matches the given regular expression.
* The "catch syscall" command now works on mips*-linux* targets.
* The -data-disassemble MI command now supports modes 2 and 3 for
dumping the instruction opcodes.
* New command line options
-data-directory DIR Specify DIR as the "data-directory".
This is mostly for testing purposes.
* The "maint set python auto-load on|off" command has been renamed to
"set auto-load-scripts on|off".
* GDB has a new command: "set directories".
It is like the "dir" command except that it replaces the
source path list instead of augmenting it.
* GDB now understands thread names.
On GNU/Linux, "info threads" will display the thread name as set by
prctl or pthread_setname_np.
There is also a new command, "thread name", which can be used to
assign a name internally for GDB to display.
* OpenCL C
Initial support for the OpenCL C language (
has been integrated into GDB.
* Python scripting
** The function gdb.Write now accepts an optional keyword 'stream'.
This keyword, when provided, will direct the output to either
stdout, stderr, or GDB's logging output.
** Parameters can now be be sub-classed in Python, and in particular
you may implement the get_set_doc and get_show_doc functions.
This improves how Parameter set/show documentation is processed
and allows for more dynamic content.
** Symbols, Symbol Table, Symbol Table and Line, Object Files,
Inferior, Inferior Thread, Blocks, and Block Iterator APIs now
have an is_valid method.
** Breakpoints can now be sub-classed in Python, and in particular
you may implement a 'stop' function that is executed each time
the inferior reaches that breakpoint.
** New function gdb.lookup_global_symbol looks up a global symbol.
** GDB values in Python are now callable if the value represents a
function. For example, if 'some_value' represents a function that
takes two integer parameters and returns a value, you can call
that function like so:
result = some_value (10,20)
** Module gdb.types has been added.
It contains a collection of utilities for working with gdb.Types objects:
get_basic_type, has_field, make_enum_dict.
** Module gdb.printing has been added.
It contains utilities for writing and registering pretty-printers.
New classes: PrettyPrinter, SubPrettyPrinter,
New function: register_pretty_printer.
** New commands "info pretty-printers", "enable pretty-printer" and
"disable pretty-printer" have been added.
** gdb.parameter("directories") is now available.
** New function gdb.newest_frame returns the newest frame in the
selected thread.
** The gdb.InferiorThread class has a new "name" attribute. This
holds the thread's name.
** Python Support for Inferior events.
Python scripts can add observers to be notified of events
occurring in the process being debugged.
The following events are currently supported:
- Continue event.
- Inferior exited event.
- Signal received, and Breakpoint hit events.
* C++ Improvements:
** GDB now puts template parameters in scope when debugging in an
instantiation. For example, if you have:
template<int X> int func (void) { return X; }
then if you step into func<5>, "print X" will show "5". This
feature requires proper debuginfo support from the compiler; it
was added to GCC 4.5.
** The motion commands "next", "finish", "until", and "advance" now
work better when exceptions are thrown. In particular, GDB will
no longer lose control of the inferior; instead, the GDB will
stop the inferior at the point at which the exception is caught.
This functionality requires a change in the exception handling
code that was introduced in GCC 4.5.
* GDB now follows GCC's rules on accessing volatile objects when
reading or writing target state during expression evaluation.
One notable difference to prior behavior is that "print x = 0"
no longer generates a read of x; the value of the assignment is
now always taken directly from the value being assigned.
* GDB now has some support for using labels in the program's source in
linespecs. For instance, you can use "advance label" to continue
execution to a label.
* GDB now has support for reading and writing a new .gdb_index
section. This section holds a fast index of DWARF debugging
information and can be used to greatly speed up GDB startup and
operation. See the documentation for `save gdb-index' for details.
* The "watch" command now accepts an optional "-location" argument.
When used, this causes GDB to watch the memory referred to by the
expression. Such a watchpoint is never deleted due to it going out
of scope.
* GDB now supports thread debugging of core dumps on GNU/Linux.
GDB now activates thread debugging using the libthread_db library
when debugging GNU/Linux core dumps, similarly to when debugging
live processes. As a result, when debugging a core dump file, GDB
is now able to display pthread_t ids of threads. For example, "info
threads" shows the same output as when debugging the process when it
was live. In earlier releases, you'd see something like this:
(gdb) info threads
* 1 LWP 6780 main () at main.c:10
While now you see this:
(gdb) info threads
* 1 Thread 0x7f0f5712a700 (LWP 6780) main () at main.c:10
It is also now possible to inspect TLS variables when debugging core
When debugging a core dump generated on a machine other than the one
used to run GDB, you may need to point GDB at the correct
libthread_db library with the "set libthread-db-search-path"
command. See the user manual for more details on this command.
* When natively debugging programs on PowerPC BookE processors running
a Linux kernel version 2.6.34 or later, GDB supports ranged breakpoints,
which stop execution of the inferior whenever it executes an instruction
at any address within the specified range. See the "PowerPC Embedded"
section in the user manual for more details.
* New features in the GDB remote stub, GDBserver
** GDBserver is now supported on PowerPC LynxOS (versions 4.x and 5.x),
and i686 LynxOS (version 5.x).
** GDBserver is now supported on Blackfin Linux.
* New native configurations
ia64 HP-UX ia64-*-hpux*
* New targets:
Analog Devices, Inc. Blackfin Processor bfin-*
* Ada task switching is now supported on sparc-elf targets when
debugging a program using the Ravenscar Profile. For more information,
see the "Tasking Support when using the Ravenscar Profile" section
in the GDB user manual.
* Guile support was removed.
* New features in the GNU simulator
** The --map-info flag lists all known core mappings.
** CFI flashes may be simulated via the "cfi" device.
*** Changes in GDB 7.2
* Shared library support for remote targets by default
When GDB is configured for a generic, non-OS specific target, like
for example, --target=arm-eabi or one of the many *-*-elf targets,
GDB now queries remote stubs for loaded shared libraries using the
`qXfer:libraries:read' packet. Previously, shared library support
was always disabled for such configurations.
* C++ Improvements:
** Argument Dependent Lookup (ADL)
In C++ ADL lookup directs function search to the namespaces of its
arguments even if the namespace has not been imported.
For example:
namespace A
class B { };
void foo (B) { }
A::B b
Here the compiler will search for `foo' in the namespace of 'b'
and find A::foo. GDB now supports this. This construct is commonly
used in the Standard Template Library for operators.
** Improved User Defined Operator Support
In addition to member operators, GDB now supports lookup of operators
defined in a namespace and imported with a `using' directive, operators
defined in the global scope, operators imported implicitly from an
anonymous namespace, and the ADL operators mentioned in the previous
GDB now also supports proper overload resolution for all the previously
mentioned flavors of operators.
** static const class members
Printing of static const class members that are initialized in the
class definition has been fixed.
* Windows Thread Information Block access.
On Windows targets, GDB now supports displaying the Windows Thread
Information Block (TIB) structure. This structure is visible either
by using the new command `info w32 thread-information-block' or, by
dereferencing the new convenience variable named `$_tlb', a
thread-specific pointer to the TIB. This feature is also supported
when remote debugging using GDBserver.
* Static tracepoints
Static tracepoints are calls in the user program into a tracing
library. One such library is a port of the LTTng kernel tracer to
userspace --- UST (LTTng Userspace Tracer,
When debugging with GDBserver, GDB now supports combining the GDB
tracepoint machinery with such libraries. For example: the user can
use GDB to probe a static tracepoint marker (a call from the user
program into the tracing library) with the new "strace" command (see
"New commands" below). This creates a "static tracepoint" in the
breakpoint list, that can be manipulated with the same feature set
as fast and regular tracepoints. E.g., collect registers, local and
global variables, collect trace state variables, and define
tracepoint conditions. In addition, the user can collect extra
static tracepoint marker specific data, by collecting the new
$_sdata internal variable. When analyzing the trace buffer, you can
inspect $_sdata like any other variable available to GDB. For more
information, see the "Tracepoints" chapter in GDB user manual. New
remote packets have been defined to support static tracepoints, see
the "New remote packets" section below.
* Better reconstruction of tracepoints after disconnected tracing
GDB will attempt to download the original source form of tracepoint
definitions when starting a trace run, and then will upload these
upon reconnection to the target, resulting in a more accurate
reconstruction of the tracepoints that are in use on the target.
* Observer mode
You can now exercise direct control over the ways that GDB can
affect your program. For instance, you can disallow the setting of
breakpoints, so that the program can run continuously (assuming
non-stop mode). In addition, the "observer" variable is available
to switch all of the different controls; in observer mode, GDB
cannot affect the target's behavior at all, which is useful for
tasks like diagnosing live systems in the field.
* The new convenience variable $_thread holds the number of the
current thread.
* New remote packets
Return the address of the Windows Thread Information Block of a given thread.
In response to several of the tracepoint packets, the target may now
also respond with a number of intermediate `qRelocInsn' request
packets before the final result packet, to have GDB handle
relocating an instruction to execute at a different address. This
is particularly useful for stubs that support fast tracepoints. GDB
reports support for this feature in the qSupported packet.
List static tracepoint markers in the target program.
List static tracepoint markers at a given address in the target
Read the static trace data collected (by a `collect $_sdata'
tracepoint action). The remote stub reports support for this packet
to gdb's qSupported query.
Send the current settings of GDB's permission flags.
Send part of the source (textual) form of a tracepoint definition,
which includes location, conditional, and action list.
* The source command now accepts a -s option to force searching for the
script in the source search path even if the script name specifies
a directory.
* New features in the GDB remote stub, GDBserver
- GDBserver now support tracepoints (including fast tracepoints, and
static tracepoints). The feature is currently supported by the
i386-linux and amd64-linux builds. See the "Tracepoints support
in gdbserver" section in the manual for more information.
GDBserver JIT compiles the tracepoint's conditional agent
expression bytecode into native code whenever possible for low
overhead dynamic tracepoints conditionals. For such tracepoints,
an expression that examines program state is evaluated when the
tracepoint is reached, in order to determine whether to capture
trace data. If the condition is simple and false, processing the
tracepoint finishes very quickly and no data is gathered.
GDBserver interfaces with the UST (LTTng Userspace Tracer) library
for static tracepoints support.
- GDBserver now supports x86_64 Windows 64-bit debugging.
* GDB now sends xmlRegisters= in qSupported packet to indicate that
it understands register description.
* The --batch flag now disables pagination and queries.
* X86 general purpose registers
GDB now supports reading/writing byte, word and double-word x86
general purpose registers directly. This means you can use, say,
$ah or $ax to refer, respectively, to the byte register AH and
16-bit word register AX that are actually portions of the 32-bit
register EAX or 64-bit register RAX.
* The `commands' command now accepts a range of breakpoints to modify.
A plain `commands' following a command that creates multiple
breakpoints affects all the breakpoints set by that command. This
applies to breakpoints set by `rbreak', and also applies when a
single `break' command creates multiple breakpoints (e.g.,
breakpoints on overloaded c++ functions).
* The `rbreak' command now accepts a filename specification as part of
its argument, limiting the functions selected by the regex to those
in the specified file.
* Support for remote debugging Windows and SymbianOS shared libraries
from Unix hosts has been improved. Non Windows GDB builds now can
understand target reported file names that follow MS-DOS based file
system semantics, such as file names that include drive letters and
use the backslash character as directory separator. This makes it
possible to transparently use the "set sysroot" and "set
solib-search-path" on Unix hosts to point as host copies of the
target's shared libraries. See the new command "set
target-file-system-kind" described below, and the "Commands to
specify files" section in the user manual for more information.
* New commands
eval template, expressions...
Convert the values of one or more expressions under the control
of the string template to a command line, and call it.
set target-file-system-kind unix|dos-based|auto
show target-file-system-kind
Set or show the assumed file system kind for target reported file
save breakpoints <filename>
Save all current breakpoint definitions to a file suitable for use
in a later debugging session. To read the saved breakpoint
definitions, use the `source' command.
`save tracepoints' is a new alias for `save-tracepoints'. The latter
is now deprecated.
info static-tracepoint-markers
Display information about static tracepoint markers in the target.
strace FN | FILE:LINE | *ADDR | -m MARKER_ID
Define a static tracepoint by probing a marker at the given
function, line, address, or marker ID.
set observer on|off
show observer
Enable and disable observer mode.
set may-write-registers on|off
set may-write-memory on|off
set may-insert-breakpoints on|off
set may-insert-tracepoints on|off
set may-insert-fast-tracepoints on|off
set may-interrupt on|off
Set individual permissions for GDB effects on the target. Note that
some of these settings can have undesirable or surprising
consequences, particularly when changed in the middle of a session.
For instance, disabling the writing of memory can prevent
breakpoints from being inserted, cause single-stepping to fail, or
even crash your program, if you disable after breakpoints have been
inserted. However, GDB should not crash.
set record memory-query on|off
show record memory-query
Control whether to stop the inferior if memory changes caused
by an instruction cannot be recorded.
* Changed commands
The disassemble command now supports "start,+length" form of two arguments.
* Python scripting
** GDB now provides a new directory location, called the python directory,
where Python scripts written for GDB can be installed. The location
of that directory is <data-directory>/python, where <data-directory>
is the GDB data directory. For more details, see section `Scripting
GDB using Python' in the manual.
** The GDB Python API now has access to breakpoints, symbols, symbol
tables, program spaces, inferiors, threads and frame's code blocks.
Additionally, GDB Parameters can now be created from the API, and
manipulated via set/show in the CLI.
** New functions gdb.target_charset, gdb.target_wide_charset,
gdb.progspaces, gdb.current_progspace, and gdb.string_to_argv.
** New exception gdb.GdbError.
** Pretty-printers are now also looked up in the current program space.
** Pretty-printers can now be individually enabled and disabled.
** GDB now looks for names of Python scripts to auto-load in a
special section named `.debug_gdb_scripts', in addition to looking
for a script when OBJFILE is read by the debugger.
* Tracepoint actions were unified with breakpoint commands. In particular,
there are no longer differences in "info break" output for breakpoints and
tracepoints and the "commands" command can be used for both tracepoints and
regular breakpoints.
* New targets
ARM Symbian arm*-*-symbianelf*
* D language support.
GDB now supports debugging programs written in the D programming
* GDB now supports the extended ptrace interface for PowerPC which is
available since Linux kernel version 2.6.34. This automatically enables
any hardware breakpoints and additional hardware watchpoints available in
the processor. The old ptrace interface exposes just one hardware
watchpoint and no hardware breakpoints.
* GDB is now able to use the Data Value Compare (DVC) register available on
embedded PowerPC processors to implement in hardware simple watchpoint
conditions of the form:
This works in native GDB running on Linux kernels with the extended ptrace
interface mentioned above.
*** Changes in GDB 7.1
* C++ Improvements
** Namespace Support
GDB now supports importing of namespaces in C++. This enables the
user to inspect variables from imported namespaces. Support for
namepace aliasing has also been added. So, if a namespace is
aliased in the current scope (e.g. namepace C=A; ) the user can
print variables using the alias (e.g. (gdb) print C::x).
** Bug Fixes
All known bugs relating to the printing of virtual base class were
fixed. It is now possible to call overloaded static methods using a
qualified name.
** Cast Operators
The C++ cast operators static_cast<>, dynamic_cast<>, const_cast<>,
and reinterpret_cast<> are now handled by the C++ expression parser.
* New targets
Xilinx MicroBlaze microblaze-*-*
Renesas RX rx-*-elf
* New Simulators
Xilinx MicroBlaze microblaze
Renesas RX rx
* Multi-program debugging.
GDB now has support for multi-program (a.k.a. multi-executable or
multi-exec) debugging. This allows for debugging multiple inferiors
simultaneously each running a different program under the same GDB
session. See "Debugging Multiple Inferiors and Programs" in the
manual for more information. This implied some user visible changes
in the multi-inferior support. For example, "info inferiors" now
lists inferiors that are not running yet or that have exited
already. See also "New commands" and "New options" below.
* New tracing features
GDB's tracepoint facility now includes several new features:
** Trace state variables
GDB tracepoints now include support for trace state variables, which
are variables managed by the target agent during a tracing
experiment. They are useful for tracepoints that trigger each
other, so for instance one tracepoint can count hits in a variable,
and then a second tracepoint has a condition that is true when the
count reaches a particular value. Trace state variables share the
$-syntax of GDB convenience variables, and can appear in both
tracepoint actions and condition expressions. Use the "tvariable"
command to create, and "info tvariables" to view; see "Trace State
Variables" in the manual for more detail.
** Fast tracepoints
GDB now includes an option for defining fast tracepoints, which
targets may implement more efficiently, such as by installing a jump
into the target agent rather than a trap instruction. The resulting
speedup can be by two orders of magnitude or more, although the
tradeoff is that some program locations on some target architectures
might not allow fast tracepoint installation, for instance if the
instruction to be replaced is shorter than the jump. To request a
fast tracepoint, use the "ftrace" command, with syntax identical to
the regular trace command.
** Disconnected tracing
It is now possible to detach GDB from the target while it is running
a trace experiment, then reconnect later to see how the experiment
is going. In addition, a new variable disconnected-tracing lets you
tell the target agent whether to continue running a trace if the
connection is lost unexpectedly.
** Trace files
GDB now has the ability to save the trace buffer into a file, and
then use that file as a target, similarly to you can do with
corefiles. You can select trace frames, print data that was
collected in them, and use tstatus to display the state of the
tracing run at the moment that it was saved. To create a trace
file, use "tsave <filename>", and to use it, do "target tfile
** Circular trace buffer
You can ask the target agent to handle the trace buffer as a
circular buffer, discarding the oldest trace frames to make room for
newer ones, by setting circular-trace-buffer to on. This feature may
not be available for all target agents.
* Changed commands
The disassemble command, when invoked with two arguments, now requires
the arguments to be comma-separated.
info variables
The info variables command now displays variable definitions. Files
which only declare a variable are not shown.
The source command is now capable of sourcing Python scripts.
This feature is dependent on the debugger being build with Python
Related to this enhancement is also the introduction of a new command
"set script-extension" (see below).
* New commands (for set/show, see "New options" below)
record save [<FILENAME>]
Save a file (in core file format) containing the process record
execution log for replay debugging at a later time.
record restore <FILENAME>
Restore the process record execution log that was saved at an
earlier time, for replay debugging.
add-inferior [-copies <N>] [-exec <FILENAME>]
Add a new inferior.
clone-inferior [-copies <N>] [ID]
Make a new inferior ready to execute the same program another
inferior has loaded.
remove-inferior ID
Remove an inferior.
maint info program-spaces
List the program spaces loaded into GDB.
set remote interrupt-sequence [Ctrl-C | BREAK | BREAK-g]
show remote interrupt-sequence
Allow the user to select one of ^C, a BREAK signal or BREAK-g
as the sequence to the remote target in order to interrupt the execution.
Ctrl-C is a default. Some system prefers BREAK which is high level of
serial line for some certain time. Linux kernel prefers BREAK-g, a.k.a
Magic SysRq g. It is BREAK signal and character 'g'.
set remote interrupt-on-connect [on | off]
show remote interrupt-on-connect
When interrupt-on-connect is ON, gdb sends interrupt-sequence to
remote target when gdb connects to it. This is needed when you debug
Linux kernel.
set remotebreak [on | off]
show remotebreak
Deprecated. Use "set/show remote interrupt-sequence" instead.
tvariable $NAME [ = EXP ]
Create or modify a trace state variable.
info tvariables
List trace state variables and their values.
delete tvariable $NAME ...
Delete one or more trace state variables.
teval EXPR, ...
Evaluate the given expressions without collecting anything into the
trace buffer. (Valid in tracepoint actions only.)
ftrace FN / FILE:LINE / *ADDR
Define a fast tracepoint at the given function, line, or address.
* New expression syntax
GDB now parses the 0b prefix of binary numbers the same way as GCC does.
GDB now parses 0b101010 identically with 42.
* New options
set follow-exec-mode new|same
show follow-exec-mode
Control whether GDB reuses the same inferior across an exec call or
creates a new one. This is useful to be able to restart the old
executable after the inferior having done an exec call.
set default-collect EXPR, ...
show default-collect
Define a list of expressions to be collected at each tracepoint.
This is a useful way to ensure essential items are not overlooked,
such as registers or a critical global variable.
set disconnected-tracing
show disconnected-tracing
If set to 1, the target is instructed to continue tracing if it
loses its connection to GDB. If 0, the target is to stop tracing
upon disconnection.
set circular-trace-buffer
show circular-trace-buffer
If set to on, the target is instructed to use a circular trace buffer
and discard the oldest trace frames instead of stopping the trace due
to a full trace buffer. If set to off, the trace stops when the buffer
fills up. Some targets may not support this.
set script-extension off|soft|strict
show script-extension
If set to "off", the debugger does not perform any script language
recognition, and all sourced files are assumed to be GDB scripts.
If set to "soft" (the default), files are sourced according to
filename extension, falling back to GDB scripts if the first
evaluation failed.
If set to "strict", files are sourced according to filename extension.
set ada trust-PAD-over-XVS on|off
show ada trust-PAD-over-XVS
If off, activate a workaround against a bug in the debugging information
generated by the compiler for PAD types (see gcc/ in
the GCC sources for more information about the GNAT encoding and
PAD types in particular). It is always safe to set this option to
off, but this introduces a slight performance penalty. The default
is on.
* Python API Improvements
** GDB provides the new class gdb.LazyString. This is useful in
some pretty-printing cases. The new method gdb.Value.lazy_string
provides a simple way to create objects of this type.
** The fields returned by gdb.Type.fields now have an
`is_base_class' attribute.
** The new method gdb.Type.range returns the range of an array type.
** The new method gdb.parse_and_eval can be used to parse and
evaluate an expression.
* New remote packets
Define a trace state variable.
Get the current value of a trace state variable.
Set desired tracing behavior upon disconnection.
Set the trace buffer to be linear or circular.
qTfP, qTsP
Get data about the tracepoints currently in use.
* Bug fixes
Process record now works correctly with hardware watchpoints.
Multiple bug fixes have been made to the mips-irix port, making it
much more reliable. In particular:
- Debugging threaded applications is now possible again. Previously,
GDB would hang while starting the program, or while waiting for
the program to stop at a breakpoint.
- Attaching to a running process no longer hangs.
- An error occurring while loading a core file has been fixed.
- Changing the value of the PC register now works again. This fixes
problems observed when using the "jump" command, or when calling
a function from GDB, or even when assigning a new value to $pc.
- With the "finish" and "return" commands, the return value for functions
returning a small array is now correctly printed.
- It is now possible to break on shared library code which gets executed
during a shared library init phase (code executed while executing
their .init section). Previously, the breakpoint would have no effect.
- GDB is now able to backtrace through the signal handler for
non-threaded programs.
PIE (Position Independent Executable) programs debugging is now supported.
This includes debugging execution of PIC (Position Independent Code) shared
libraries although for that, it should be possible to run such libraries as an
executable program.
*** Changes in GDB 7.0
* GDB now has an interface for JIT compilation. Applications that
dynamically generate code can create symbol files in memory and register
them with GDB. For users, the feature should work transparently, and
for JIT developers, the interface is documented in the GDB manual in the
"JIT Compilation Interface" chapter.
* Tracepoints may now be conditional. The syntax is as for
breakpoints; either an "if" clause appended to the "trace" command,
or the "condition" command is available. GDB sends the condition to
the target for evaluation using the same bytecode format as is used
for tracepoint actions.
* The disassemble command now supports: an optional /r modifier, print the
raw instructions in hex as well as in symbolic form, and an optional /m
modifier to print mixed source+assembly.
* Process record and replay
In a architecture environment that supports ``process record and
replay'', ``process record and replay'' target can record a log of
the process execution, and replay it with both forward and reverse
execute commands.
* Reverse debugging: GDB now has new commands reverse-continue, reverse-
step, reverse-next, reverse-finish, reverse-stepi, reverse-nexti, and
set execution-direction {forward|reverse}, for targets that support
reverse execution.
* GDB now supports hardware watchpoints on MIPS/Linux systems. This
feature is available with a native GDB running on kernel version
2.6.28 or later.
* GDB now has support for multi-byte and wide character sets on the
target. Strings whose character type is wchar_t, char16_t, or
char32_t are now correctly printed. GDB supports wide- and unicode-
literals in C, that is, L'x', L"string", u'x', u"string", U'x', and
U"string" syntax. And, GDB allows the "%ls" and "%lc" formats in
`printf'. This feature requires iconv to work properly; if your
system does not have a working iconv, GDB can use GNU libiconv. See
the installation instructions for more information.
* GDB now supports automatic retrieval of shared library files from
remote targets. To use this feature, specify a system root that begins
with the `remote:' prefix, either via the `set sysroot' command or via
the `--with-sysroot' configure-time option.
* "info sharedlibrary" now takes an optional regex of libraries to show,
and it now reports if a shared library has no debugging information.
* Commands `set debug-file-directory', `set solib-search-path' and `set args'
now complete on file names.
* When completing in expressions, gdb will attempt to limit
completions to allowable structure or union fields, where appropriate.
For instance, consider:
# struct example { int f1; double f2; };
# struct example variable;
(gdb) p variable.
If the user types TAB at the end of this command line, the available
completions will be "f1" and "f2".
* Inlined functions are now supported. They show up in backtraces, and
the "step", "next", and "finish" commands handle them automatically.
* GDB now supports the token-splicing (##) and stringification (#)
operators when expanding macros. It also supports variable-arity
* GDB now supports inspecting extra signal information, exported by
the new $_siginfo convenience variable. The feature is currently
implemented on linux ARM, i386 and amd64.
* GDB can now display the VFP floating point registers and NEON vector
registers on ARM targets. Both ARM GNU/Linux native GDB and gdbserver
can provide these registers (requires Linux 2.6.30 or later). Remote
and simulator targets may also provide them.
* New remote packets
Search memory for a sequence of bytes.
Turn off `+'/`-' protocol acknowledgments to permit more efficient
operation over reliable transport links. Use of this packet is
controlled by the `set remote noack-packet' command.
Kill the process with the specified process ID. Use this in preference
to `k' when multiprocess protocol extensions are supported.
Obtains additional operating system information
Read or write additional signal information.
* Removed remote protocol undocumented extension
An undocumented extension to the remote protocol's `S' stop reply
packet that permited the stub to pass a process id was removed.
Remote servers should use the `T' stop reply packet instead.
* GDB now supports multiple function calling conventions according to the
DWARF-2 DW_AT_calling_convention function attribute.
* The SH target utilizes the aforementioned change to distinguish between gcc
and Renesas calling convention. It also adds the new CLI commands
`set/show sh calling-convention'.
* GDB can now read compressed debug sections, as produced by GNU gold
with the --compress-debug-sections=zlib flag.
* 64-bit core files are now supported on AIX.
* Thread switching is now supported on Tru64.
* Watchpoints can now be set on unreadable memory locations, e.g. addresses
which will be allocated using malloc later in program execution.
* The qXfer:libraries:read remote procotol packet now allows passing a
list of section offsets.
* On GNU/Linux, GDB can now attach to stopped processes. Several race
conditions handling signals delivered during attach or thread creation
have also been fixed.
* GDB now supports the use of DWARF boolean types for Ada's type Boolean.
From the user's standpoint, all unqualified instances of True and False
are treated as the standard definitions, regardless of context.
* GDB now parses C++ symbol and type names more flexibly. For
example, given:
template<typename T> class C { };
C<char const *> c;
GDB will now correctly handle all of:
ptype C<char const *>
ptype C<char const*>
ptype C<const char *>
ptype C<const char*>
* New features in the GDB remote stub, gdbserver
- The "--wrapper" command-line argument tells gdbserver to use a
wrapper program to launch programs for debugging.
- On PowerPC and S/390 targets, it is now possible to use a single
gdbserver executable to debug both 32-bit and 64-bit programs.
(This requires gdbserver itself to be built as a 64-bit executable.)
- gdbserver uses the new noack protocol mode for TCP connections to
reduce communications latency, if also supported and enabled in GDB.
- Support for the sparc64-linux-gnu target is now included in
- The amd64-linux build of gdbserver now supports debugging both
32-bit and 64-bit programs.
- The i386-linux, amd64-linux, and i386-win32 builds of gdbserver
now support hardware watchpoints, and will use them automatically
as appropriate.
* Python scripting
GDB now has support for scripting using Python. Whether this is
available is determined at configure time.
New GDB commands can now be written in Python.
* Ada tasking support
Ada tasks can now be inspected in GDB. The following commands have
been introduced:
info tasks
Print the list of Ada tasks.
info task N
Print detailed information about task number N.
Print the task number of the current task.
task N
Switch the context of debugging to task number N.
* Support for user-defined prefixed commands. The "define" command can
add new commands to existing prefixes, e.g. "target".
* Multi-inferior, multi-process debugging.
GDB now has generalized support for multi-inferior debugging. See
"Debugging Multiple Inferiors" in the manual for more information.
Although availability still depends on target support, the command
set is more uniform now. The GNU/Linux specific multi-forks support
has been migrated to this new framework. This implied some user
visible changes; see "New commands" and also "Removed commands"
* Target descriptions can now describe the target OS ABI. See the
"Target Description Format" section in the user manual for more
* Target descriptions can now describe "compatible" architectures
to indicate that the target can execute applications for a different
architecture in addition to those for the main target architecture.
See the "Target Description Format" section in the user manual for
more information.
* Multi-architecture debugging.
GDB now includes general supports for debugging applications on
hybrid systems that use more than one single processor architecture
at the same time. Each such hybrid architecture still requires
specific support to be added. The only hybrid architecture supported
in this version of GDB is the Cell Broadband Engine.
* GDB now supports integrated debugging of Cell/B.E. applications that
use both the PPU and SPU architectures. To enable support for hybrid
Cell/B.E. debugging, you need to configure GDB to support both the
powerpc-linux or powerpc64-linux and the spu-elf targets, using the
--enable-targets configure option.
* Non-stop mode debugging.
For some targets, GDB now supports an optional mode of operation in
which you can examine stopped threads while other threads continue
to execute freely. This is referred to as non-stop mode, with the
old mode referred to as all-stop mode. See the "Non-Stop Mode"
section in the user manual for more information.
To be able to support remote non-stop debugging, a remote stub needs
to implement the non-stop mode remote protocol extensions, as
described in the "Remote Non-Stop" section of the user manual. The
GDB remote stub, gdbserver, has been adjusted to support these
extensions on linux targets.
* New commands (for set/show, see "New options" below)
catch syscall [NAME(S) | NUMBER(S)]
Catch system calls. Arguments, which should be names of system
calls or their numbers, mean catch only those syscalls. Without
arguments, every syscall will be caught. When the inferior issues
any of the specified syscalls, GDB will stop and announce the system
call, both when it is called and when its call returns. This
feature is currently available with a native GDB running on the
Linux Kernel, under the following architectures: x86, x86_64,
PowerPC and PowerPC64.
find [/size-char] [/max-count] start-address, end-address|+search-space-size,
val1 [, val2, ...]
Search memory for a sequence of bytes.
maint set python print-stack
maint show python print-stack
Show a stack trace when an error is encountered in a Python script.
python [CODE]
Invoke CODE by passing it to the Python interpreter.
macro define
macro list
macro undef
These allow macros to be defined, undefined, and listed
info os processes
Show operating system information about processes.
info inferiors
List the inferiors currently under GDB's control.
inferior NUM
Switch focus to inferior number NUM.
detach inferior NUM
Detach from inferior number NUM.
kill inferior NUM
Kill inferior number NUM.
* New options
set spu stop-on-load
show spu stop-on-load
Control whether to stop for new SPE threads during Cell/B.E. debugging.
set spu auto-flush-cache
show spu auto-flush-cache
Control whether to automatically flush the software-managed cache
during Cell/B.E. debugging.
set sh calling-convention
show sh calling-convention
Control the calling convention used when calling SH target functions.
set debug timestamp
show debug timestamp
Control display of timestamps with GDB debugging output.
set disassemble-next-line
show disassemble-next-line
Control display of disassembled source lines or instructions when
the debuggee stops.
set remote noack-packet
show remote noack-packet
Set/show the use of remote protocol QStartNoAckMode packet. See above
under "New remote packets."
set remote query-attached-packet
show remote query-attached-packet
Control use of remote protocol `qAttached' (query-attached) packet.
set remote read-siginfo-object
show remote read-siginfo-object
Control use of remote protocol `qXfer:siginfo:read' (read-siginfo-object)
set remote write-siginfo-object
show remote write-siginfo-object
Control use of remote protocol `qXfer:siginfo:write' (write-siginfo-object)
set remote reverse-continue
show remote reverse-continue
Control use of remote protocol 'bc' (reverse-continue) packet.
set remote reverse-step
show remote reverse-step
Control use of remote protocol 'bs' (reverse-step) packet.
set displaced-stepping
show displaced-stepping
Control displaced stepping mode. Displaced stepping is a way to
single-step over breakpoints without removing them from the debuggee.
Also known as "out-of-line single-stepping".
set debug displaced
show debug displaced
Control display of debugging info for displaced stepping.
maint set internal-error
maint show internal-error
Control what GDB does when an internal error is detected.
maint set internal-warning
maint show internal-warning
Control what GDB does when an internal warning is detected.
set exec-wrapper
show exec-wrapper
unset exec-wrapper
Use a wrapper program to launch programs for debugging.
set multiple-symbols (all|ask|cancel)
show multiple-symbols
The value of this variable can be changed to adjust the debugger behavior
when an expression or a breakpoint location contains an ambiguous symbol
name (an overloaded function name, for instance).
set breakpoint always-inserted
show breakpoint always-inserted
Keep breakpoints always inserted in the target, as opposed to inserting
them when resuming the target, and removing them when the target stops.
This option can improve debugger performance on slow remote targets.
set arm fallback-mode (arm|thumb|auto)
show arm fallback-mode
set arm force-mode (arm|thumb|auto)
show arm force-mode
These commands control how ARM GDB determines whether instructions
are ARM or Thumb. The default for both settings is auto, which uses
the current CPSR value for instructions without symbols; previous
versions of GDB behaved as if "set arm fallback-mode arm".
set disable-randomization
show disable-randomization
Standalone programs run with the virtual address space randomization enabled
by default on some platforms. This option keeps the addresses stable across
multiple debugging sessions.
set non-stop
show non-stop
Control whether other threads are stopped or not when some thread hits
a breakpoint.
set target-async
show target-async
Requests that asynchronous execution is enabled in the target, if available.
In this case, it's possible to resume target in the background, and interact
with GDB while the target is running. "show target-async" displays the
current state of asynchronous execution of the target.
set target-wide-charset
show target-wide-charset
The target-wide-charset is the name of the character set that GDB
uses when printing characters whose type is wchar_t.
set tcp auto-retry (on|off)
show tcp auto-retry
set tcp connect-timeout
show tcp connect-timeout
These commands allow GDB to retry failed TCP connections to a remote stub
with a specified timeout period; this is useful if the stub is launched
in parallel with GDB but may not be ready to accept connections immediately.
set libthread-db-search-path
show libthread-db-search-path
Control list of directories which GDB will search for appropriate
set schedule-multiple (on|off)
show schedule-multiple
Allow GDB to resume all threads of all processes or only threads of
the current process.
set stack-cache
show stack-cache
Use more aggressive caching for accesses to the stack. This improves
performance of remote debugging (particularly backtraces) without
affecting correctness.
set interactive-mode (on|off|auto)
show interactive-mode
Control whether GDB runs in interactive mode (on) or not (off).
When in interactive mode, GDB waits for the user to answer all
queries. Otherwise, GDB does not wait and assumes the default
answer. When set to auto (the default), GDB determines which
mode to use based on the stdin settings.
* Removed commands
info forks
For program forks, this is replaced by the new more generic `info
inferiors' command. To list checkpoints, you can still use the
`info checkpoints' command, which was an alias for the `info forks'
fork NUM
Replaced by the new `inferior' command. To switch between
checkpoints, you can still use the `restart' command, which was an
alias for the `fork' command.
process PID
This is removed, since some targets don't have a notion of
processes. To switch between processes, you can still use the
`inferior' command using GDB's own inferior number.
delete fork NUM
For program forks, this is replaced by the new more generic `kill
inferior' command. To delete a checkpoint, you can still use the
`delete checkpoint' command, which was an alias for the `delete
fork' command.
detach fork NUM
For program forks, this is replaced by the new more generic `detach
inferior' command. To detach a checkpoint, you can still use the
`detach checkpoint' command, which was an alias for the `detach
fork' command.
* New native configurations
x86/x86_64 Darwin i[34567]86-*-darwin*
x86_64 MinGW x86_64-*-mingw*
* New targets
Lattice Mico32 lm32-*
x86 DICOS i[34567]86-*-dicos*
x86_64 DICOS x86_64-*-dicos*
S+core 3 score-*-*
* The GDB remote stub, gdbserver, now supports x86 Windows CE
(mingw32ce) debugging.
* Removed commands
catch load
catch unload
These commands were actually not implemented on any target.
*** Changes in GDB 6.8
* New native configurations
NetBSD/hppa hppa*-*netbsd*
Xtensa GNU/Linux xtensa*-*-linux*
* New targets
NetBSD/hppa hppa*-*-netbsd*
Xtensa GNU/Lunux xtensa*-*-linux*
* Change in command line behavior -- corefiles vs. process ids.
When the '-p NUMBER' or '--pid NUMBER' options are used, and
attaching to process NUMBER fails, GDB no longer attempts to open a
core file named NUMBER. Attaching to a program using the -c option
is no longer supported. Instead, use the '-p' or '--pid' options.
* GDB can now be built as a native debugger for debugging Windows x86
(mingw32) Portable Executable (PE) programs.
* Pending breakpoints no longer change their number when their address
is resolved.
* GDB now supports breakpoints with multiple locations,
including breakpoints on C++ constructors, inside C++ templates,
and in inlined functions.
* GDB's ability to debug optimized code has been improved. GDB more
accurately identifies function bodies and lexical blocks that occupy
more than one contiguous range of addresses.
* Target descriptions can now describe registers for PowerPC.
* The GDB remote stub, gdbserver, now supports the AltiVec and SPE
registers on PowerPC targets.
* The GDB remote stub, gdbserver, now supports thread debugging on GNU/Linux
targets even when the libthread_db library is not available.
* The GDB remote stub, gdbserver, now supports the new file transfer
commands (remote put, remote get, and remote delete).
* The GDB remote stub, gdbserver, now supports run and attach in
extended-remote mode.
* hppa*64*-*-hpux11* target broken
The debugger is unable to start a program and fails with the following
error: "Error trying to get information about dynamic linker".
The gdb-6.7 release is also affected.
* GDB now supports the --enable-targets= configure option to allow
building a single GDB executable that supports multiple remote
target architectures.
* GDB now supports debugging C and C++ programs which use the
Decimal Floating Point extension. In addition, the PowerPC target
now has a set of pseudo-registers to inspect decimal float values
stored in two consecutive float registers.
* The -break-insert MI command can optionally create pending
breakpoints now.
* Improved support for debugging Ada
Many improvements to the Ada language support have been made. These
- Better support for Ada2005 interface types
- Improved handling of arrays and slices in general
- Better support for Taft-amendment types
- The '{type} ADDRESS' expression is now allowed on the left hand-side
of an assignment
- Improved command completion in Ada
- Several bug fixes
* GDB on GNU/Linux and HP/UX can now debug through "exec" of a new
* New commands
set print frame-arguments (all|scalars|none)
show print frame-arguments
The value of this variable can be changed to control which argument
values should be printed by the debugger when displaying a frame.
remote put
remote get
remote delete
Transfer files to and from a remote target, and delete remote files.
* New MI commands
Transfer files to and from a remote target, and delete remote files.
* New remote packets
Open, close, read, write, and delete files on the remote system.
Attach to an existing process on the remote system, in extended-remote
Run a new process on the remote system, in extended-remote mode.
*** Changes in GDB 6.7
* Resolved 101 resource leaks, null pointer dereferences, etc. in gdb,
bfd, libiberty and opcodes, as revealed by static analysis donated by
Coverity, Inc. (
* When looking up multiply-defined global symbols, GDB will now prefer the
symbol definition in the current shared library if it was built using the
-Bsymbolic linker option.
* When the Text User Interface (TUI) is not configured, GDB will now
recognize the -tui command-line option and print a message that the TUI
is not supported.
* The GDB remote stub, gdbserver, now has lower overhead for high
frequency signals (e.g. SIGALRM) via the QPassSignals packet.
* GDB for MIPS targets now autodetects whether a remote target provides
32-bit or 64-bit register values.
* Support for C++ member pointers has been improved.
* GDB now understands XML target descriptions, which specify the
target's overall architecture. GDB can read a description from
a local file or over the remote serial protocol.
* Vectors of single-byte data use a new integer type which is not
automatically displayed as character or string data.
* The /s format now works with the print command. It displays
arrays of single-byte integers and pointers to single-byte integers
as strings.
* Target descriptions can now describe target-specific registers,
for architectures which have implemented the support (currently
only ARM, M68K, and MIPS).
* GDB and the GDB remote stub, gdbserver, now support the XScale
iWMMXt coprocessor.
* The GDB remote stub, gdbserver, has been updated to support
ARM Windows CE (mingw32ce) debugging, and GDB Windows CE support
has been rewritten to use the standard GDB remote protocol.
* GDB can now step into C++ functions which are called through thunks.
* GDB for the Cell/B.E. SPU now supports overlay debugging.
* The GDB remote protocol "qOffsets" packet can now honor ELF segment
layout. It also supports a TextSeg= and DataSeg= response when only
segment base addresses (rather than offsets) are available.
* The /i format now outputs any trailing branch delay slot instructions
immediately following the last instruction within the count specified.
* The GDB remote protocol "T" stop reply packet now supports a
"library" response. Combined with the new "qXfer:libraries:read"
packet, this response allows GDB to debug shared libraries on targets
where the operating system manages the list of loaded libraries (e.g.
Windows and SymbianOS).
* The GDB remote stub, gdbserver, now supports dynamic link libraries
(DLLs) on Windows and Windows CE targets.
* GDB now supports a faster verification that a .debug file matches its binary
according to its build-id signature, if the signature is present.
* New commands
set remoteflow
show remoteflow
Enable or disable hardware flow control (RTS/CTS) on the serial port
when debugging using remote targets.
set mem inaccessible-by-default
show mem inaccessible-by-default
If the target supplies a memory map, for instance via the remote
protocol's "qXfer:memory-map:read" packet, setting this variable
prevents GDB from accessing memory outside the memory map. This
is useful for targets with memory mapped registers or which react
badly to accesses of unmapped address space.
set breakpoint auto-hw
show breakpoint auto-hw
If the target supplies a memory map, for instance via the remote
protocol's "qXfer:memory-map:read" packet, setting this variable
lets GDB use hardware breakpoints automatically for memory regions
where it can not use software breakpoints. This covers both the
"break" command and internal breakpoints used for other commands
including "next" and "finish".
catch exception
catch exception unhandled
Stop the program execution when Ada exceptions are raised.
catch assert
Stop the program execution when an Ada assertion failed.
set sysroot
show sysroot
Set an alternate system root for target files. This is a more
general version of "set solib-absolute-prefix", which is now
an alias to "set sysroot".
info spu
Provide extended SPU facility status information. This set of
commands is available only when debugging the Cell/B.E. SPU
* New native configurations
OpenBSD/sh sh*-*openbsd*
set tdesc filename
unset tdesc filename
show tdesc filename
Use the specified local file as an XML target description, and do
not query the target for its built-in description.
* New targets
OpenBSD/sh sh*-*-openbsd*
MIPS64 GNU/Linux (gdbserver) mips64-linux-gnu
Toshiba Media Processor mep-elf
* New remote packets
Ignore the specified signals; pass them directly to the debugged program
without stopping other threads or reporting them to GDB.
Read an XML target description from the target, which describes its
Read or write contents of an spufs file on the target system. These
packets are available only on the Cell/B.E. SPU architecture.
Report the loaded shared libraries. Combined with new "T" packet
response, this packet allows GDB to debug shared libraries on
targets where the operating system manages the list of loaded
libraries (e.g. Windows and SymbianOS).
* Removed targets
Support for these obsolete configurations has been removed.
* Other removed features
target abug
target cpu32bug
target est
target rom68k
Various m68k-only ROM monitors.
target hms
target e7000
target sh3
target sh3e
Various Renesas ROM monitors and debugging interfaces for SH and
target ocd
Support for a Macraigor serial interface to on-chip debugging.
GDB does not directly support the newer parallel or USB
DWARF 1 support
A debug information format. The predecessor to DWARF 2 and
DWARF 3, which are still supported.
Support for the HP aCC compiler on HP-UX/PA-RISC
SOM-encapsulated symbolic debugging information, automatic
invocation of pxdb, and the aCC custom C++ ABI. This does not
affect HP-UX for Itanium or GCC for HP-UX/PA-RISC. Code compiled
with aCC can still be debugged on an assembly level.
MIPS ".pdr" sections
A MIPS-specific format used to describe stack frame layout
in debugging information.
Scheme support
GDB could work with an older version of Guile to debug
the interpreter and Scheme programs running in it.
set mips stack-arg-size
set mips saved-gpreg-size
Use "set mips abi" to control parameter passing for MIPS.
*** Changes in GDB 6.6
* New targets
Xtensa xtensa-elf
Cell Broadband Engine SPU spu-elf
* GDB can now be configured as a cross-debugger targeting native Windows
(mingw32) or Cygwin. It can communicate with a remote debugging stub
running on a Windows system over TCP/IP to debug Windows programs.
* The GDB remote stub, gdbserver, has been updated to support Windows and
Cygwin debugging. Both single-threaded and multi-threaded programs are
* The "set trust-readonly-sections" command works again. This command was
broken in GDB 6.3, 6.4, and 6.5.
* The "load" command now supports writing to flash memory, if the remote
stub provides the required support.
* Support for GNU/Linux Thread Local Storage (TLS, per-thread variables) no
longer requires symbolic debug information (e.g. DWARF-2).
* New commands
set substitute-path
unset substitute-path
show substitute-path
Manage a list of substitution rules that GDB uses to rewrite the name
of the directories where the sources are located. This can be useful
for instance when the sources were moved to a different location
between compilation and debugging.
set trace-commands
show trace-commands
Print each CLI command as it is executed. Each command is prefixed with
a number of `+' symbols representing the nesting depth.
The source command now has a `-v' option to enable the same feature.
* REMOVED features
The ARM Demon monitor support (RDP protocol, "target rdp").
Kernel Object Display, an embedded debugging feature which only worked with
an obsolete version of Cisco IOS.
The 'set download-write-size' and 'show download-write-size' commands.
* New remote packets
Tell a stub about GDB client features, and request remote target features.
The first feature implemented is PacketSize, which allows the target to
specify the size of packets it can handle - to minimize the number of
packets required and improve performance when connected to a remote
Fetch an OS auxilliary vector from the remote stub. This packet is a
more efficient replacement for qPart:auxv:read.
Fetch a memory map from the remote stub, including information about
RAM, ROM, and flash memory devices.
Erase and program a flash memory device.
* Removed remote packets
This packet has been replaced by qXfer:auxv:read. Only GDB 6.4 and 6.5
used it, and only gdbserver implemented it.
*** Changes in GDB 6.5
* New targets
Renesas M32C/M16C m32c-elf
Morpho Technologies ms1 ms1-elf
* New commands
init-if-undefined Initialize a convenience variable, but
only if it doesn't already have a value.
The following commands are presently only implemented for native GNU/Linux:
checkpoint Save a snapshot of the program state.
restart <n> Return the program state to a
previously saved state.
info checkpoints List currently saved checkpoints.
delete-checkpoint <n> Delete a previously saved checkpoint.
set|show detach-on-fork Tell gdb whether to detach from a newly
forked process, or to keep debugging it.
info forks List forks of the user program that
are available to be debugged.
fork <n> Switch to debugging one of several
forks of the user program that are
available to be debugged.
delete-fork <n> Delete a fork from the list of forks
that are available to be debugged (and
kill the forked process).
detach-fork <n> Delete a fork from the list of forks
that are available to be debugged (and
allow the process to continue).
* New architecture
Morpho Technologies ms2 ms1-elf
* Improved Windows host support
GDB now builds as a cross debugger hosted on i686-mingw32, including
native console support, and remote communications using either
network sockets or serial ports.
* Improved Modula-2 language support
GDB can now print most types in the Modula-2 syntax. This includes:
basic types, set types, record types, enumerated types, range types,
pointer types and ARRAY types. Procedure var parameters are correctly
printed and hexadecimal addresses and character constants are also
written in the Modula-2 syntax. Best results can be obtained by using
GNU Modula-2 together with the -gdwarf-2 command line option.
* REMOVED features
The ARM rdi-share module.
The Netware NLM debug server.
*** Changes in GDB 6.4
* New native configurations
OpenBSD/arm arm*-*-openbsd*
OpenBSD/mips64 mips64-*-openbsd*
* New targets
Morpho Technologies ms1 ms1-elf
* New command line options
--batch-silent As for --batch, but totally silent.
--return-child-result The debugger will exist with the same value
the child (debugged) program exited with.
--eval-command COMMAND, -ex COMMAND
Execute a single GDB CLI command. This may be
specified multiple times and in conjunction
with the --command (-x) option.
* Deprecated commands removed
The following commands, that were deprecated in 2000, have been
Command Replacement
set|show arm disassembly-flavor set|show arm disassembler
othernames set arm disassembler
set|show remotedebug set|show debug remote
set|show archdebug set|show debug arch
set|show eventdebug set|show debug event
regs info registers
* New BSD user-level threads support
It is now possible to debug programs using the user-level threads
library on OpenBSD and FreeBSD. Currently supported (target)
configurations are:
FreeBSD/amd64 x86_64-*-freebsd*
FreeBSD/i386 i386-*-freebsd*
OpenBSD/i386 i386-*-openbsd*
Note that the new kernel threads libraries introduced in FreeBSD 5.x
are not yet supported.
* New support for Matsushita MN10300 w/sim added
(Work in progress). mn10300-elf.
* REMOVED configurations and files
VxWorks and the XDR protocol *-*-vxworks
Motorola MCORE mcore-*-*
National Semiconductor NS32000 ns32k-*-*
* New "set print array-indexes" command
After turning this setting "on", GDB prints the index of each element
when displaying arrays. The default is "off" to preserve the previous
* VAX floating point support
GDB now supports the not-quite-ieee VAX F and D floating point formats.
* User-defined command support
In addition to using $arg0..$arg9 for argument passing, it is now possible
to use $argc to determine now many arguments have been passed. See the
section on user-defined commands in the user manual for more information.
*** Changes in GDB 6.3:
* New command line option
GDB now accepts -l followed by a number to set the timeout for remote
* GDB works with GCC -feliminate-dwarf2-dups
GDB now supports a more compact representation of DWARF-2 debug
information using DW_FORM_ref_addr references. These are produced
by GCC with the option -feliminate-dwarf2-dups and also by some
proprietary compilers. With GCC, you must use GCC 3.3.4 or later
to use -feliminate-dwarf2-dups.
* Internationalization
When supported by the host system, GDB will be built with
internationalization (libintl). The task of marking up the sources is
continued, we're looking forward to our first translation.
* Ada
Initial support for debugging programs compiled with the GNAT
implementation of the Ada programming language has been integrated
into GDB. In this release, support is limited to expression evaluation.
* New native configurations
GNU/Linux/m32r m32r-*-linux-gnu
* Remote 'p' packet
GDB's remote protocol now includes support for the 'p' packet. This
packet is used to fetch individual registers from a remote inferior.
* END-OF-LIFE registers[] compatibility module
GDB's internal register infrastructure has been completely rewritten.
The new infrastructure making possible the implementation of key new
features including 32x64 (e.g., 64-bit amd64 GDB debugging a 32-bit
i386 application).
GDB 6.3 will be the last release to include the the registers[]
compatibility module that allowed out-of-date configurations to
continue to work. This change directly impacts the following
sds protocol
xdr protocol
powerpc bdm protocol
Unless there is activity to revive these configurations, they will be
made OBSOLETE in GDB 6.4, and REMOVED from GDB 6.5.
* OBSOLETE configurations and files
Configurations that have been declared obsolete in this release have
been commented out. Unless there is activity to revive these
configurations, the next release of GDB will have their sources
permanently REMOVED.
*** Changes in GDB 6.2.1:
* MIPS `break main; run' gave an heuristic-fence-post warning
When attempting to run even a simple program, a warning about
heuristic-fence-post being hit would be reported. This problem has
been fixed.
* MIPS IRIX 'long double' crashed GDB
When examining a long double variable, GDB would get a segmentation
fault. The crash has been fixed (but GDB 6.2 cannot correctly examine
IRIX long double values).
* VAX and "next"
A bug in the VAX stack code was causing problems with the "next"
command. This problem has been fixed.
*** Changes in GDB 6.2:
* Fix for ``many threads''
On GNU/Linux systems that use the NPTL threads library, a program
rapidly creating and deleting threads would confuse GDB leading to the
error message:
ptrace: No such process.
thread_db_get_info: cannot get thread info: generic error
This problem has been fixed.
* "-async" and "-noasync" options removed.
Support for the broken "-noasync" option has been removed (it caused
GDB to dump core).
* New ``start'' command.
This command runs the program until the begining of the main procedure.
* New BSD Kernel Data Access Library (libkvm) interface
Using ``target kvm'' it is now possible to debug kernel core dumps and
live kernel memory images on various FreeBSD, NetBSD and OpenBSD
platforms. Currently supported (native-only) configurations are:
FreeBSD/amd64 x86_64-*-freebsd*
FreeBSD/i386 i?86-*-freebsd*
NetBSD/i386 i?86-*-netbsd*
NetBSD/m68k m68*-*-netbsd*
NetBSD/sparc sparc-*-netbsd*
OpenBSD/amd64 x86_64-*-openbsd*
OpenBSD/i386 i?86-*-openbsd*
OpenBSD/m68k m68*-openbsd*
OpenBSD/sparc sparc-*-openbsd*
* Signal trampoline code overhauled
Many generic problems with GDB's signal handling code have been fixed.
These include: backtraces through non-contiguous stacks; recognition
of sa_sigaction signal trampolines; backtrace from a NULL pointer
call; backtrace through a signal trampoline; step into and out of
signal handlers; and single-stepping in the signal trampoline.
Please note that kernel bugs are a limiting factor here. These
features have been shown to work on an s390 GNU/Linux system that
include a 2.6.8-rc1 kernel. Ref PR breakpoints/1702.
* Cygwin support for DWARF 2 added.
* New native configurations
GNU/Linux/hppa hppa*-*-linux*
OpenBSD/hppa hppa*-*-openbsd*
OpenBSD/m68k m68*-*-openbsd*
OpenBSD/m88k m88*-*-openbsd*
OpenBSD/powerpc powerpc-*-openbsd*
NetBSD/vax vax-*-netbsd*
OpenBSD/vax vax-*-openbsd*
* END-OF-LIFE frame compatibility module
GDB's internal frame infrastructure has been completely rewritten.
The new infrastructure making it possible to support key new features
including DWARF 2 Call Frame Information. To aid in the task of
migrating old configurations to this new infrastructure, a
compatibility module, that allowed old configurations to continue to
work, was also included.
GDB 6.2 will be the last release to include this frame compatibility
module. This change directly impacts the following configurations:
Unless there is activity to revive these configurations, they will be
made OBSOLETE in GDB 6.3, and REMOVED from GDB 6.4.
* REMOVED configurations and files
Sun 3, running SunOS 3 m68*-*-sunos3*
Sun 3, running SunOS 4 m68*-*-sunos4*
Sun 2, running SunOS 3 m68000-*-sunos3*
Sun 2, running SunOS 4 m68000-*-sunos4*
Motorola 680x0 running LynxOS m68*-*-lynxos*
AT&T 3b1/Unix pc m68*-att-*
Bull DPX2 (68k, System V release 3) m68*-bull-sysv*
decstation mips-dec-* mips-little-*
riscos mips-*-riscos* mips-*-sysv*
sonymips mips-sony-*
sysv mips*-*-sysv4* (IRIX 5/6 not included)
*** Changes in GDB 6.1.1:
* TUI (Text-mode User Interface) built-in (also included in GDB 6.1)
The TUI (Text-mode User Interface) is now built as part of a default
GDB configuration. It is enabled by either selecting the TUI with the
command line option "-i=tui" or by running the separate "gdbtui"
program. For more information on the TUI, see the manual "Debugging
with GDB".
* Pending breakpoint support (also included in GDB 6.1)
Support has been added to allow you to specify breakpoints in shared
libraries that have not yet been loaded. If a breakpoint location
cannot be found, and the "breakpoint pending" option is set to auto,
GDB queries you if you wish to make the breakpoint pending on a future
shared-library load. If and when GDB resolves the breakpoint symbol,
the pending breakpoint is removed as one or more regular breakpoints
are created.
Pending breakpoints are very useful for GCJ Java debugging.
* Fixed ISO-C build problems
The files bfd/elf-bfd.h, gdb/dictionary.c and gdb/types.c contained
non ISO-C code that stopped them being built using a more strict ISO-C
compiler (e.g., IBM's C compiler).
* Fixed build problem on IRIX 5
Due to header problems with <sys/proc.h>, the file gdb/proc-api.c
wasn't able to compile compile on an IRIX 5 system.
* Added execute permission to gdb/gdbserver/configure
The shell script gdb/testsuite/gdb.stabs/configure lacked execute
permission. This bug would cause configure to fail on a number of
systems (Solaris, IRIX). Ref: server/519.
* Fixed build problem on hpux2.0w-hp-hpux11.00 using the HP ANSI C compiler
Older HPUX ANSI C compilers did not accept variable array sizes. somsolib.c
has been updated to use constant array sizes.
* Fixed a panic in the DWARF Call Frame Info code on Solaris 2.7
GCC 3.3.2, on Solaris 2.7, includes the DW_EH_PE_funcrel encoding in
its generated DWARF Call Frame Info. This encoding was causing GDB to
panic, that panic has been fixed. Ref: gdb/1628.
* Fixed a problem when examining parameters in shared library code.
When examining parameters in optimized shared library code generated
by a mainline GCC, GDB would incorrectly report ``Variable "..." is
not available''. GDB now correctly displays the variable's value.
*** Changes in GDB 6.1:
* Removed --with-mmalloc
Support for the mmalloc memory manager has been removed, as it
conflicted with the internal gdb byte cache.
* Changes in AMD64 configurations
The AMD64 target now includes the %cs and %ss registers. As a result
the AMD64 remote protocol has changed; this affects the floating-point
and SSE registers. If you rely on those registers for your debugging,
you should upgrade gdbserver on the remote side.
* Revised SPARC target
The SPARC target has been completely revised, incorporating the
FreeBSD/sparc64 support that was added for GDB 6.0. As a result
support for LynxOS and SunOS 4 has been dropped. Calling functions
from within GDB on operating systems with a non-executable stack
(Solaris, OpenBSD) now works.
* New C++ demangler
GDB has a new C++ demangler which does a better job on the mangled
names generated by current versions of g++. It also runs faster, so
with this and other changes gdb should now start faster on large C++
* DWARF 2 Location Expressions
GDB support for location expressions has been extended to support function
arguments and frame bases. Older versions of GDB could crash when they
encountered these.
* C++ nested types and namespaces
GDB's support for nested types and namespaces in C++ has been
improved, especially if you use the DWARF 2 debugging format. (This
is the default for recent versions of GCC on most platforms.)
Specifically, if you have a class "Inner" defined within a class or
namespace "Outer", then GDB realizes that the class's name is
"Outer::Inner", not simply "Inner". This should greatly reduce the
frequency of complaints about not finding RTTI symbols. In addition,
if you are stopped at inside of a function defined within a namespace,
GDB modifies its name lookup accordingly.
* New native configurations
NetBSD/amd64 x86_64-*-netbsd*
OpenBSD/amd64 x86_64-*-openbsd*
OpenBSD/alpha alpha*-*-openbsd*
OpenBSD/sparc sparc-*-openbsd*
OpenBSD/sparc64 sparc64-*-openbsd*
* New debugging protocols
M32R with SDI protocol m32r-*-elf*
* "set prompt-escape-char" command deleted.
The command "set prompt-escape-char" has been deleted. This command,
and its very obscure effet on GDB's prompt, was never documented,
tested, nor mentioned in the NEWS file.
* OBSOLETE configurations and files
Configurations that have been declared obsolete in this release have
been commented out. Unless there is activity to revive these
configurations, the next release of GDB will have their sources
permanently REMOVED.
Sun 3, running SunOS 3 m68*-*-sunos3*
Sun 3, running SunOS 4 m68*-*-sunos4*
Sun 2, running SunOS 3 m68000-*-sunos3*
Sun 2, running SunOS 4 m68000-*-sunos4*
Motorola 680x0 running LynxOS m68*-*-lynxos*
AT&T 3b1/Unix pc m68*-att-*
Bull DPX2 (68k, System V release 3) m68*-bull-sysv*
decstation mips-dec-* mips-little-*
riscos mips-*-riscos* mips-*-sysv*
sonymips mips-sony-*
sysv mips*-*-sysv4* (IRIX 5/6 not included)
* REMOVED configurations and files
SGI Irix-4.x mips-sgi-irix4 or iris4
SGI Iris (MIPS) running Irix V3: mips-sgi-irix or iris
Z8000 simulator z8k-zilog-none or z8ksim
Matsushita MN10200 w/simulator mn10200-*-*
H8/500 simulator h8500-hitachi-hms or h8500hms
HP/PA running BSD hppa*-*-bsd*
HP/PA running OSF/1 hppa*-*-osf*
HP/PA Pro target hppa*-*-pro*
PMAX (MIPS) running Mach 3.0 mips*-*-mach3*
386BSD i[3456]86-*-bsd*
Sequent family i[3456]86-sequent-sysv4*
SPARC running LynxOS sparc-*-lynxos*
SPARC running SunOS 4 sparc-*-sunos4*
Tsqware Sparclet sparclet-*-*
Fujitsu SPARClite sparclite-fujitsu-none or sparclite
*** Changes in GDB 6.0:
* Objective-C
Support for debugging the Objective-C programming language has been
integrated into GDB.
* New backtrace mechanism (includes DWARF 2 Call Frame Information).
DWARF 2's Call Frame Information makes available compiler generated
information that more exactly describes the program's run-time stack.
By using this information, GDB is able to provide more robust stack
The i386, amd64 (nee, x86-64), Alpha, m68hc11, ia64, and m32r targets
have been updated to use a new backtrace mechanism which includes
DWARF 2 CFI support.
* Hosted file I/O.
GDB's remote protocol has been extended to include support for hosted
file I/O (where the remote target uses GDB's file system). See GDB's
remote protocol documentation for details.
* All targets using the new architecture framework.
All of GDB's targets have been updated to use the new internal
architecture framework. The way is now open for future GDB releases
to include cross-architecture native debugging support (i386 on amd64,
ppc32 on ppc64).
* GNU/Linux's Thread Local Storage (TLS)
GDB now includes support for for the GNU/Linux implementation of
per-thread variables.
* GNU/Linux's Native POSIX Thread Library (NPTL)
GDB's thread code has been updated to work with either the new
GNU/Linux NPTL thread library or the older "LinuxThreads" library.
* Separate debug info.
GDB, in conjunction with BINUTILS, now supports a mechanism for
automatically loading debug information from a separate file. Instead
of shipping full debug and non-debug versions of system libraries,
system integrators can now instead ship just the stripped libraries
and optional debug files.
* DWARF 2 Location Expressions
DWARF 2 Location Expressions allow the compiler to more completely
describe the location of variables (even in optimized code) to the
GDB now includes preliminary support for location expressions (support
for DW_OP_piece is still missing).
* Java
A number of long standing bugs that caused GDB to die while starting a
Java application have been fixed. GDB's Java support is now
considered "useable".
* GNU/Linux support for fork, vfork, and exec.
The "catch fork", "catch exec", "catch vfork", and "set follow-fork-mode"
commands are now implemented for GNU/Linux. They require a 2.5.x or later
* GDB supports logging output to a file
There are two new commands, "set logging" and "show logging", which can be
used to capture GDB's output to a file.
* The meaning of "detach" has changed for gdbserver
The "detach" command will now resume the application, as documented. To
disconnect from gdbserver and leave it stopped, use the new "disconnect"
* d10v, m68hc11 `regs' command deprecated
The `info registers' command has been updated so that it displays the
registers using a format identical to the old `regs' command.
* Profiling support
A new command, "maint set profile on/off", has been added. This command can
be used to enable or disable profiling while running GDB, to profile a
session or a set of commands. In addition there is a new configure switch,
"--enable-profiling", which will cause GDB to be compiled with profiling
data, for more informative profiling results.
* Default MI syntax changed to "mi2".
The default MI (machine interface) syntax, enabled by the command line
option "-i=mi", has been changed to "mi2". The previous MI syntax,
"mi1", can be enabled by specifying the option "-i=mi1".
Support for the original "mi0" syntax (included in GDB 5.0) has been
Fix for gdb/192: removed extraneous space when displaying frame level.
Fix for gdb/672: update changelist is now output in mi list format.
Fix for gdb/702: a -var-assign that updates the value now shows up
in a subsequent -var-update.
* New native configurations.
FreeBSD/amd64 x86_64-*-freebsd*
* Multi-arched targets.
HP/PA HPUX11 hppa*-*-hpux*
Renesas M32R/D w/simulator m32r-*-elf*
* OBSOLETE configurations and files
Configurations that have been declared obsolete in this release have
been commented out. Unless there is activity to revive these
configurations, the next release of GDB will have their sources
permanently REMOVED.
Z8000 simulator z8k-zilog-none or z8ksim
Matsushita MN10200 w/simulator mn10200-*-*
H8/500 simulator h8500-hitachi-hms or h8500hms
HP/PA running BSD hppa*-*-bsd*
HP/PA running OSF/1 hppa*-*-osf*
HP/PA Pro target hppa*-*-pro*
PMAX (MIPS) running Mach 3.0 mips*-*-mach3*
Sequent family i[3456]86-sequent-sysv4*
Tsqware Sparclet sparclet-*-*
Fujitsu SPARClite sparclite-fujitsu-none or sparclite
* REMOVED configurations and files
Motorola Delta 88000 running Sys V m88k-motorola-sysv or delta88
IBM AIX PS/2 i[3456]86-*-aix
i386 running Mach 3.0 i[3456]86-*-mach3*
i386 running Mach i[3456]86-*-mach*
i386 running OSF/1 i[3456]86-*osf1mk*
HP/Apollo 68k Family m68*-apollo*-sysv*,
m68*-hp-bsd*, m68*-hp-hpux*
Argonaut Risc Chip (ARC) arc-*-*
Mitsubishi D30V d30v-*-*
Fujitsu FR30 fr30-*-elf*
OS/9000 i[34]86-*-os9k
I960 with MON960 i960-*-coff
* MIPS $fp behavior changed
The convenience variable $fp, for the MIPS, now consistently returns
the address of the current frame's base. Previously, depending on the
context, $fp could refer to either $sp or the current frame's base
address. See ``8.10 Registers'' in the manual ``Debugging with GDB:
The GNU Source-Level Debugger''.
*** Changes in GDB 5.3:
* GNU/Linux shared library multi-threaded performance improved.
When debugging a multi-threaded application on GNU/Linux, GDB now uses
`/proc', in preference to `ptrace' for memory reads. This may result
in an improvement in the start-up time of multi-threaded, shared
library applications when run under GDB. One GDB user writes: ``loads
shared libs like mad''.
* ``gdbserver'' now supports multi-threaded applications on some targets
Support for debugging multi-threaded applications which use
the GNU/Linux LinuxThreads package has been added for
arm*-*-linux*-gnu*, i[3456]86-*-linux*-gnu*, mips*-*-linux*-gnu*,
powerpc*-*-linux*-gnu*, and sh*-*-linux*-gnu*.
* GDB now supports C/C++ preprocessor macros.
GDB now expands preprocessor macro invocations in C/C++ expressions,
and provides various commands for showing macro definitions and how
they expand.
The new command `macro expand EXPRESSION' expands any macro
invocations in expression, and shows the result.
The new command `show macro MACRO-NAME' shows the definition of the
macro named MACRO-NAME, and where it was defined.
Most compilers don't include information about macros in the debugging
information by default. In GCC 3.1, for example, you need to compile
your program with the options `-gdwarf-2 -g3'. If the macro
information is present in the executable, GDB will read it.
* Multi-arched targets.
DEC Alpha (partial) alpha*-*-*
DEC VAX (partial) vax-*-*
NEC V850 v850-*-*
National Semiconductor NS32000 (partial) ns32k-*-*
Motorola 68000 (partial) m68k-*-*
Motorola MCORE mcore-*-*
* New targets.
Fujitsu FRV architecture added by Red Hat frv*-*-*
* New native configurations
Alpha NetBSD alpha*-*-netbsd*
SH NetBSD sh*-*-netbsdelf*
MIPS NetBSD mips*-*-netbsd*
UltraSPARC NetBSD sparc64-*-netbsd*
* OBSOLETE configurations and files
Configurations that have been declared obsolete in this release have
been commented out. Unless there is activity to revive these
configurations, the next release of GDB will have their sources
permanently REMOVED.
Mitsubishi D30V d30v-*-*
OS/9000 i[34]86-*-os9k
IBM AIX PS/2 i[3456]86-*-aix
Fujitsu FR30 fr30-*-elf*
Motorola Delta 88000 running Sys V m88k-motorola-sysv or delta88
Argonaut Risc Chip (ARC) arc-*-*
i386 running Mach 3.0 i[3456]86-*-mach3*
i386 running Mach i[3456]86-*-mach*
i386 running OSF/1 i[3456]86-*osf1mk*
HP/Apollo 68k Family m68*-apollo*-sysv*,
m68*-hp-bsd*, m68*-hp-hpux*
I960 with MON960 i960-*-coff
* OBSOLETE languages
CHILL, a Pascal like language used by telecommunications companies.
* REMOVED configurations and files
AMD 29k family via UDI a29k-amd-udi, udi29k
A29K VxWorks a29k-*-vxworks
AMD 29000 embedded, using EBMON a29k-none-none
AMD 29000 embedded with COFF a29k-none-coff
AMD 29000 embedded with a.out a29k-none-aout
testsuite/gdb.hp/gdb.threads-hp/ directory
* New command "set max-user-call-depth <nnn>"
This command allows the user to limit the call depth of user-defined
commands. The default is 1024.
* Changes in FreeBSD/i386 native debugging.
Support for the "generate-core-file" has been added.
* New commands "dump", "append", and "restore".
These commands allow data to be copied from target memory
to a bfd-format or binary file (dump and append), and back
from a file into memory (restore).
* Improved "next/step" support on multi-processor Alpha Tru64.
The previous single-step mechanism could cause unpredictable problems,
including the random appearance of SIGSEGV or SIGTRAP signals. The use
of a software single-step mechanism prevents this.
*** Changes in GDB 5.2.1:
* New targets.
Atmel AVR avr*-*-*
* Bug fixes
gdb/182: gdb/323: gdb/237: On alpha, gdb was reporting:
mdebugread.c:2443: gdb-internal-error: sect_index_data not initialized
Fix, by Joel Brobecker imported from mainline.
gdb/439: gdb/291: On some ELF object files, gdb was reporting:
dwarf2read.c:1072: gdb-internal-error: sect_index_text not initialize
Fix, by Fred Fish, imported from mainline.
Dwarf2 .debug_frame & .eh_frame handler improved in many ways.
Surprisingly enough, it works now.
By Michal Ludvig, imported from mainline.
i386 hardware watchpoint support:
avoid misses on second run for some targets.
By Pierre Muller, imported from mainline.
*** Changes in GDB 5.2:
* New command "set trust-readonly-sections on[off]".
This command is a hint that tells gdb that read-only sections
really are read-only (ie. that their contents will not change).
In this mode, gdb will go to the object file rather than the
target to read memory from read-only sections (such as ".text").
This can be a significant performance improvement on some
(notably embedded) targets.
* New command "generate-core-file" (or "gcore").
This new gdb command allows the user to drop a core file of the child
process state at any time. So far it's been implemented only for
GNU/Linux and Solaris, but should be relatively easily ported to other
hosts. Argument is core file name (defaults to core.<pid>).
* New command line option
GDB now accepts --pid or -p followed by a process id.
* Change in command line behavior -- corefiles vs. process ids.
There is a subtle behavior in the way in which GDB handles
command line arguments. The first non-flag argument is always
a program to debug, but the second non-flag argument may either
be a corefile or a process id. Previously, GDB would attempt to
open the second argument as a corefile, and if that failed, would
issue a superfluous error message and then attempt to attach it as
a process. Now, if the second argument begins with a non-digit,
it will be treated as a corefile. If it begins with a digit,
GDB will attempt to attach it as a process, and if no such process
is found, will then attempt to open it as a corefile.
* Changes in ARM configurations.
Multi-arch support is enabled for all ARM configurations. The ARM/NetBSD
configuration is fully multi-arch.
* New native configurations
ARM NetBSD arm*-*-netbsd*
x86 OpenBSD i[3456]86-*-openbsd*
AMD x86-64 running GNU/Linux x86_64-*-linux-*
Sparc64 running FreeBSD sparc64-*-freebsd*
* New targets
Sanyo XStormy16 xstormy16-elf
* OBSOLETE configurations and files
Configurations that have been declared obsolete in this release have
been commented out. Unless there is activity to revive these
configurations, the next release of GDB will have their sources
permanently REMOVED.
AMD 29k family via UDI a29k-amd-udi, udi29k
A29K VxWorks a29k-*-vxworks
AMD 29000 embedded, using EBMON a29k-none-none
AMD 29000 embedded with COFF a29k-none-coff
AMD 29000 embedded with a.out a29k-none-aout
testsuite/gdb.hp/gdb.threads-hp/ directory
* REMOVED configurations and files
TI TMS320C80 tic80-*-*
WDC 65816 w65-*-*
PowerPC Solaris powerpcle-*-solaris*
PowerPC Windows NT powerpcle-*-cygwin32
PowerPC Netware powerpc-*-netware*
Harris/CXUX m88k m88*-harris-cxux*
Most ns32k hosts and targets ns32k-*-mach3* ns32k-umax-*
ns32k-utek-sysv* ns32k-utek-*
SunOS 4.0.Xi on i386 i[3456]86-*-sunos*
Ultracomputer (29K) running Sym1 a29k-nyu-sym1 a29k-*-kern*
Sony NEWS (68K) running NEWSOS 3.x m68*-sony-sysv news
ISI Optimum V (3.05) under 4.3bsd. m68*-isi-*
Apple Macintosh (MPW) host and target N/A host, powerpc-*-macos*
* Changes to command line processing
The new `--args' feature can be used to specify command-line arguments
for the inferior from gdb's command line.
* Changes to key bindings
There is a new `operate-and-get-next' function bound to `C-o'.
*** Changes in GDB 5.1.1
Fix compile problem on DJGPP.
Fix a problem with floating-point registers on the i386 being
Fix to stop GDB crashing on .debug_str debug info.
Numerous documentation fixes.
Numerous testsuite fixes.
*** Changes in GDB 5.1:
* New native configurations
Alpha FreeBSD alpha*-*-freebsd*
x86 FreeBSD 3.x and 4.x i[3456]86*-freebsd[34]*
MIPS GNU/Linux mips*-*-linux*
MIPS SGI Irix 6.x mips*-sgi-irix6*
ia64 AIX ia64-*-aix*
s390 and s390x GNU/Linux {s390,s390x}-*-linux*
* New targets
Motorola 68HC11 and 68HC12 m68hc11-elf
CRIS cris-axis
UltraSparc running GNU/Linux sparc64-*-linux*
* OBSOLETE configurations and files
x86 FreeBSD before 2.2 i[3456]86*-freebsd{1,2.[01]}*,
Harris/CXUX m88k m88*-harris-cxux*
Most ns32k hosts and targets ns32k-*-mach3* ns32k-umax-*
ns32k-utek-sysv* ns32k-utek-*
TI TMS320C80 tic80-*-*
WDC 65816 w65-*-*
Ultracomputer (29K) running Sym1 a29k-nyu-sym1 a29k-*-kern*
PowerPC Solaris powerpcle-*-solaris*
PowerPC Windows NT powerpcle-*-cygwin32
PowerPC Netware powerpc-*-netware*
SunOS 4.0.Xi on i386 i[3456]86-*-sunos*
Sony NEWS (68K) running NEWSOS 3.x m68*-sony-sysv news
ISI Optimum V (3.05) under 4.3bsd. m68*-isi-*
Apple Macintosh (MPW) host N/A
stuff.c (Program to stuff files into a specially prepared space in kdb)
kdb-start.c (Main loop for the standalone kernel debugger)
Configurations that have been declared obsolete in this release have
been commented out. Unless there is activity to revive these
configurations, the next release of GDB will have their sources
permanently REMOVED.
* REMOVED configurations and files
Altos 3068 m68*-altos-*
Convex c1-*-*, c2-*-*
Pyramid pyramid-*-*
ARM RISCix arm-*-* (as host)
Tahoe tahoe-*-*
ser-ocd.c *-*-*
* GDB has been converted to ISO C.
GDB's source code has been converted to ISO C. In particular, the
sources are fully protoized, and rely on standard headers being
* Other news:
* "info symbol" works on platforms which use COFF, ECOFF, XCOFF, and NLM.
* The MI enabled by default.
The new machine oriented interface (MI) introduced in GDB 5.0 has been
revised and enabled by default. Packages which use GDB as a debugging
engine behind a UI or another front end are encouraged to switch to
using the GDB/MI interface, instead of the old annotations interface
which is now deprecated.
* Support for debugging Pascal programs.
GDB now includes support for debugging Pascal programs. The following
main features are supported:
- Pascal-specific data types such as sets;
- automatic recognition of Pascal sources based on file-name
- Pascal-style display of data types, variables, and functions;
- a Pascal expression parser.
However, some important features are not yet supported.
- Pascal string operations are not supported at all;
- there are some problems with boolean types;
- Pascal type hexadecimal constants are not supported
because they conflict with the internal variables format;
- support for Pascal objects and classes is not full yet;
- unlike Pascal, GDB is case-sensitive for symbol names.
* Changes in completion.
Commands such as `shell', `run' and `set args', which pass arguments
to inferior programs, now complete on file names, similar to what
users expect at the shell prompt.
Commands which accept locations, such as `disassemble', `print',
`breakpoint', `until', etc. now complete on filenames as well as
program symbols. Thus, if you type "break foob TAB", and the source
files linked into the programs include `foobar.c', that file name will
be one of the candidates for completion. However, file names are not
considered for completion after you typed a colon that delimits a file
name from a name of a function in that file, as in "break foo.c:bar".
`set demangle-style' completes on available demangling styles.
* New platform-independent commands:
It is now possible to define a post-hook for a command as well as a
hook that runs before the command. For more details, see the
documentation of `hookpost' in the GDB manual.
* Changes in GNU/Linux native debugging.
Support for debugging multi-threaded programs has been completely
revised for all platforms except m68k and sparc. You can now debug as
many threads as your system allows you to have.
Attach/detach is supported for multi-threaded programs.
Support for SSE registers was added for x86. This doesn't work for
multi-threaded programs though.
* Changes in MIPS configurations.
Multi-arch support is enabled for all MIPS configurations.
GDB can now be built as native debugger on SGI Irix 6.x systems for
debugging n32 executables. (Debugging 64-bit executables is not yet
* Unified support for hardware watchpoints in all x86 configurations.
Most (if not all) native x86 configurations support hardware-assisted
breakpoints and watchpoints in a unified manner. This support
implements debug register sharing between watchpoints, which allows to
put a virtually infinite number of watchpoints on the same address,
and also supports watching regions up to 16 bytes with several debug
The new maintenance command `maintenance show-debug-regs' toggles
debugging print-outs in functions that insert, remove, and test
watchpoints and hardware breakpoints.
* Changes in the DJGPP native configuration.
New command ``info dos sysinfo'' displays assorted information about
the CPU, OS, memory, and DPMI server.
New commands ``info dos gdt'', ``info dos ldt'', and ``info dos idt''
display information about segment descriptors stored in GDT, LDT, and
New commands ``info dos pde'' and ``info dos pte'' display entries
from Page Directory and Page Tables (for now works with CWSDPMI only).
New command ``info dos address-pte'' displays the Page Table entry for
a given linear address.
GDB can now pass command lines longer than 126 characters to the
program being debugged (requires an update to the libdbg.a library
which is part of the DJGPP development kit).
DWARF2 debug info is now supported.
It is now possible to `step' and `next' through calls to `longjmp'.
* Changes in documentation.
All GDB documentation was converted to GFDL, the GNU Free
Documentation License.
Tracepoints-related commands are now fully documented in the GDB
TUI, the Text-mode User Interface, is now documented in the manual.
Tracepoints-related commands are now fully documented in the GDB
The "GDB Internals" manual now has an index. It also includes
documentation of `ui_out' functions, GDB coding standards, x86
hardware watchpoints, and memory region attributes.
* GDB's version number moved to ``''
The Makefile variable VERSION has been replaced by the file
``''. People creating GDB distributions should update the
contents of this file.
* gdba.el deleted
GUD support is now a standard part of the EMACS distribution.
*** Changes in GDB 5.0:
* Improved support for debugging FP programs on x86 targets
Unified and much-improved support for debugging floating-point
programs on all x86 targets. In particular, ``info float'' now
displays the FP registers in the same format on all x86 targets, with
greater level of detail.
* Improvements and bugfixes in hardware-assisted watchpoints
It is now possible to watch array elements, struct members, and
bitfields with hardware-assisted watchpoints. Data-read watchpoints
on x86 targets no longer erroneously trigger when the address is
* Improvements in the native DJGPP version of GDB
The distribution now includes all the scripts and auxiliary files
necessary to build the native DJGPP version on MS-DOS/MS-Windows
machines ``out of the box''.
The DJGPP version can now debug programs that use signals. It is
possible to catch signals that happened in the debuggee, deliver
signals to it, interrupt it with Ctrl-C, etc. (Previously, a signal
would kill the program being debugged.) Programs that hook hardware
interrupts (keyboard, timer, etc.) can also be debugged.
It is now possible to debug DJGPP programs that redirect their
standard handles or switch them to raw (as opposed to cooked) mode, or
even close them. The command ``run < foo > bar'' works as expected,
and ``info terminal'' reports useful information about the debuggee's
terminal, including raw/cooked mode, redirection, etc.
The DJGPP version now uses termios functions for console I/O, which
enables debugging graphics programs. Interrupting GDB with Ctrl-C
also works.
DOS-style file names with drive letters are now fully supported by
It is now possible to debug DJGPP programs that switch their working
directory. It is also possible to rerun the debuggee any number of
times without restarting GDB; thus, you can use the same setup,
breakpoints, etc. for many debugging sessions.
* New native configurations
ARM GNU/Linux arm*-*-linux*
PowerPC GNU/Linux powerpc-*-linux*
* New targets
Motorola MCore mcore-*-*
x86 VxWorks i[3456]86-*-vxworks*
PowerPC VxWorks powerpc-*-vxworks*
TI TMS320C80 tic80-*-*
* OBSOLETE configurations
Altos 3068 m68*-altos-*
Convex c1-*-*, c2-*-*
Pyramid pyramid-*-*
ARM RISCix arm-*-* (as host)
Tahoe tahoe-*-*
Configurations that have been declared obsolete will be commented out,
but the code will be left in place. If there is no activity to revive
these configurations before the next release of GDB, the sources will
be permanently REMOVED.
* Gould support removed
Support for the Gould PowerNode and NP1 has been removed.
* New features for SVR4
On SVR4 native platforms (such as Solaris), if you attach to a process
without first loading a symbol file, GDB will now attempt to locate and
load symbols from the running process's executable file.
* Many C++ enhancements
C++ support has been greatly improved. Overload resolution now works properly
in almost all cases. RTTI support is on the way.
* Remote targets can connect to a sub-program
A popen(3) style serial-device has been added. This device starts a
sub-process (such as a stand-alone simulator) and then communicates
with that. The sub-program to run is specified using the syntax
``|<program> <args>'' vis:
(gdb) set remotedebug 1
(gdb) target extended-remote |mn10300-elf-sim program-args
* MIPS 64 remote protocol
A long standing bug in the mips64 remote protocol where by GDB
expected certain 32 bit registers (ex SR) to be transfered as 32
instead of 64 bits has been fixed.
The command ``set remote-mips64-transfers-32bit-regs on'' has been
added to provide backward compatibility with older versions of GDB.
* ``set remotebinarydownload'' replaced by ``set remote X-packet''
The command ``set remotebinarydownload'' command has been replaced by
``set remote X-packet''. Other commands in ``set remote'' family
include ``set remote P-packet''.
* Breakpoint commands accept ranges.
The breakpoint commands ``enable'', ``disable'', and ``delete'' now
accept a range of breakpoints, e.g. ``5-7''. The tracepoint command
``tracepoint passcount'' also accepts a range of tracepoints.
* ``apropos'' command added.
The ``apropos'' command searches through command names and
documentation strings, printing out matches, making it much easier to
try to find a command that does what you are looking for.
* New MI interface
A new machine oriented interface (MI) has been added to GDB. This
interface is designed for debug environments running GDB as a separate
process. This is part of the long term libGDB project. See the
"GDB/MI" chapter of the GDB manual for further information. It can be
enabled by configuring with:
.../configure --enable-gdbmi
*** Changes in GDB-4.18:
* New native configurations
HP-UX 10.20 hppa*-*-hpux10.20
HP-UX 11.x hppa*-*-hpux11.0*
M68K GNU/Linux m68*-*-linux*
* New targets
Fujitsu FR30 fr30-*-elf*
Intel StrongARM strongarm-*-*
Mitsubishi D30V d30v-*-*
* OBSOLETE configurations
Gould PowerNode, NP1 np1-*-*, pn-*-*
Configurations that have been declared obsolete will be commented out,
but the code will be left in place. If there is no activity to revive
these configurations before the next release of GDB, the sources will
be permanently REMOVED.
As a compatibility experiment, GDB's source files buildsym.h and
buildsym.c have been converted to pure standard C, no longer
containing any K&R compatibility code. We believe that all systems in
use today either come with a standard C compiler, or have a GCC port
available. If this is not true, please report the affected
configuration to immediately. See the README file for
information about getting a standard C compiler if you don't have one
* Readline 2.2
GDB now uses readline 2.2.
* set extension-language
You can now control the mapping between filename extensions and source
languages by using the `set extension-language' command. For instance,
you can ask GDB to treat .c files as C++ by saying
set extension-language .c c++
The command `info extensions' lists all of the recognized extensions
and their associated languages.
* Setting processor type for PowerPC and RS/6000
When GDB is configured for a powerpc*-*-* or an rs6000*-*-* target,
you can use the `set processor' command to specify what variant of the
PowerPC family you are debugging. The command
set processor NAME
sets the PowerPC/RS6000 variant to NAME. GDB knows about the
following PowerPC and RS6000 variants:
ppc-uisa PowerPC UISA - a PPC processor as viewed by user-level code
rs6000 IBM RS6000 ("POWER") architecture, user-level view
403 IBM PowerPC 403
403GC IBM PowerPC 403GC
505 Motorola PowerPC 505
860 Motorola PowerPC 860 or 850
601 Motorola PowerPC 601
602 Motorola PowerPC 602
603 Motorola/IBM PowerPC 603 or 603e
604 Motorola PowerPC 604 or 604e
750 Motorola/IBM PowerPC 750 or 750
At the moment, this command just tells GDB what to name the
special-purpose processor registers. Since almost all the affected
registers are inaccessible to user-level programs, this command is
only useful for remote debugging in its present form.
* HP-UX support
Thanks to a major code donation from Hewlett-Packard, GDB now has much
more extensive support for HP-UX. Added features include shared
library support, kernel threads and hardware watchpoints for 11.00,
support for HP's ANSI C and C++ compilers, and a compatibility mode
for xdb and dbx commands.
* Catchpoints
HP's donation includes the new concept of catchpoints, which is a
generalization of the old catch command. On HP-UX, it is now possible
to catch exec, fork, and vfork, as well as library loading.
This means that the existing catch command has changed; its first
argument now specifies the type of catch to be set up. See the
output of "help catch" for a list of catchpoint types.
* Debugging across forks
On HP-UX, you can choose which process to debug when a fork() happens
in the inferior.
HP has donated a curses-based terminal user interface (TUI). To get
it, build with --enable-tui. Although this can be enabled for any
configuration, at present it only works for native HP debugging.
* GDB remote protocol additions
A new protocol packet 'X' that writes binary data is now available.
Default behavior is to try 'X', then drop back to 'M' if the stub
fails to respond. The settable variable `remotebinarydownload'
allows explicit control over the use of 'X'.
For 64-bit targets, the memory packets ('M' and 'm') can now contain a
full 64-bit address. The command
set remoteaddresssize 32
can be used to revert to the old behaviour. For existing remote stubs
the change should not be noticed, as the additional address information
will be discarded.
In order to assist in debugging stubs, you may use the maintenance
command `packet' to send any text string to the stub. For instance,
maint packet heythere
sends the packet "$heythere#<checksum>". Note that it is very easy to
disrupt a debugging session by sending the wrong packet at the wrong
The compare-sections command allows you to compare section data on the
target to what is in the executable file without uploading or
downloading, by comparing CRC checksums.
* Tracing can collect general expressions
You may now collect general expressions at tracepoints. This requires
further additions to the target-side stub; see tracepoint.c and
doc/agentexpr.texi for further details.
* mask-address variable for Mips
For Mips targets, you may control the zeroing of the upper 32 bits of
a 64-bit address by entering `set mask-address on'. This is mainly
of interest to users of embedded R4xxx and R5xxx processors.
* Higher serial baud rates
GDB's serial code now allows you to specify baud rates 57600, 115200,
230400, and 460800 baud. (Note that your host system may not be able
to achieve all of these rates.)
* i960 simulator
The i960 configuration now includes an initial implementation of a
builtin simulator, contributed by Jim Wilson.
*** Changes in GDB-4.17:
* New native configurations
Alpha GNU/Linux alpha*-*-linux*
Unixware 2.x i[3456]86-unixware2*
Irix 6.x mips*-sgi-irix6*
PowerPC GNU/Linux powerpc-*-linux*
PowerPC Solaris powerpcle-*-solaris*
Sparc GNU/Linux sparc-*-linux*
Motorola sysV68 R3V7.1 m68k-motorola-sysv
* New targets
Argonaut Risc Chip (ARC) arc-*-*
Hitachi H8/300S h8300*-*-*
Matsushita MN10200 w/simulator mn10200-*-*
Matsushita MN10300 w/simulator mn10300-*-*
MIPS NEC VR4100 mips64*vr4100*{,el}-*-elf*
MIPS NEC VR5000 mips64*vr5000*{,el}-*-elf*
MIPS Toshiba TX39 mips64*tx39*{,el}-*-elf*
Mitsubishi D10V w/simulator d10v-*-*
Mitsubishi M32R/D w/simulator m32r-*-elf*
Tsqware Sparclet sparclet-*-*
NEC V850 w/simulator v850-*-*
* New debugging protocols
ARM with RDI protocol arm*-*-*
M68K with dBUG monitor m68*-*-{aout,coff,elf}
DDB and LSI variants of PMON protocol mips*-*-*
PowerPC with DINK32 monitor powerpc{,le}-*-eabi
PowerPC with SDS protocol powerpc{,le}-*-eabi
Macraigor OCD (Wiggler) devices powerpc{,le}-*-eabi
All configurations can now understand and use the DWARF 2 debugging
format. The choice is automatic, if the symbol file contains DWARF 2
* Java frontend
GDB now includes basic Java language support. This support is
only useful with Java compilers that produce native machine code.
* solib-absolute-prefix and solib-search-path
For SunOS and SVR4 shared libraries, you may now set the prefix for
loading absolute shared library symbol files, and the search path for
locating non-absolute shared library symbol files.
* Live range splitting
GDB can now effectively debug code for which GCC has performed live
range splitting as part of its optimization. See gdb/doc/LRS for
more details on the expected format of the stabs information.
* Hurd support
GDB's support for the GNU Hurd, including thread debugging, has been
updated to work with current versions of the Hurd.
* ARM Thumb support
GDB's ARM target configuration now handles the ARM7T (Thumb) 16-bit
instruction set. ARM GDB automatically detects when Thumb
instructions are in use, and adjusts disassembly and backtracing
* MIPS16 support
GDB's MIPS target configurations now handle the MIP16 16-bit
instruction set.
* Overlay support
GDB now includes support for overlays; if an executable has been
linked such that multiple sections are based at the same address, GDB
will decide which section to use for symbolic info. You can choose to
control the decision manually, using overlay commands, or implement
additional target-side support and use "overlay load-target" to bring
in the overlay mapping. Do "help overlay" for more detail.
* info symbol
The command "info symbol <address>" displays information about<