What has changed in GDB?
(Organized release by release)
-*** Changes since GDB 7.10
+*** Changes since GDB 7.12
+
+* GDB now supports access to the PKU register on GNU/Linux. The register is
+ added by the Memory Protection Keys for Userspace feature which will be
+ available in future Intel CPUs.
+
+* GDB now supports C++11 rvalue references.
+
+* Python Scripting
+
+ ** New functions to start, stop and access a running btrace recording.
+ ** Rvalue references are now supported in gdb.Type.
+
+* GDB now supports recording and replaying rdrand and rdseed Intel 64
+ instructions.
+
+* Building GDB and GDBserver now requires a C++11 compiler.
+
+ For example, GCC 4.8 or later.
+
+ It is no longer possible to build GDB or GDBserver with a C
+ compiler. The --disable-build-with-cxx configure option has been
+ removed.
+
+* Building GDB and GDBserver now requires GNU make >= 3.81.
+
+ It is no longer supported to build GDB or GDBserver with another
+ implementation of the make program or an earlier version of GNU make.
+
+* Native debugging on MS-Windows supports command-line redirection
+
+ Command-line arguments used for starting programs on MS-Windows can
+ now include redirection symbols supported by native Windows shells,
+ such as '<', '>', '>>', '2>&1', etc. This affects GDB commands such
+ as "run", "start", and "set args", as well as the corresponding MI
+ features.
+
+* Support for thread names on MS-Windows.
+
+ GDB now catches and handles the special exception that programs
+ running on MS-Windows use to assign names to threads in the
+ debugger.
+
+* Support for Java programs compiled with gcj has been removed.
+
+* User commands now accept an unlimited number of arguments.
+ Previously, only up to 10 was accepted.
+
+* The "eval" command now expands user-defined command arguments.
+
+ This makes it easier to process a variable number of arguments:
+
+ define mycommand
+ set $i = 0
+ while $i < $argc
+ eval "print $arg%d", $i
+ set $i = $i + 1
+ end
+ end
+
+* Target descriptions can now describe registers for sparc32 and sparc64.
+
+* GDB now supports DWARF version 5 (debug information format).
+ Its .debug_names index is not yet supported.
+
+* New native configurations
+
+FreeBSD/mips mips*-*-freebsd
+
+
+* New targets
+
+Synopsys ARC arc*-*-elf32
+FreeBSD/mips mips*-*-freebsd
+
+* New commands
+
+flash-erase
+ Erases all the flash memory regions reported by the target.
+
+* New MI commands
+
+-target-flash-erase
+ Erases all the flash memory regions reported by the target. This is
+ equivalent to the CLI command flash-erase.
+
+-file-list-shared-libraries
+ List the shared libraries in the program. This is
+ equivalent to the CLI command "info shared".
+
+* New commands
+
+set disassembler-options
+show disassembler-options
+ Controls the passing of target specific information to the disassembler.
+ If it is necessary to specify more than one disassembler option then
+ multiple options can be placed together into a comma separated list.
+ The default value is the empty string. Currently, the only supported
+ targets are ARM, PowerPC and S/390.
+
+maint print arc arc-instruction address
+ Print internal disassembler information about instruction at a given address.
+
+* Removed targets and native configurations
+
+Alpha running FreeBSD alpha*-*-freebsd*
+Alpha running GNU/kFreeBSD alpha*-*-kfreebsd*-gnu
+
+*** Changes in GDB 7.12
+
+* GDB and GDBserver now build with a C++ compiler by default.
+
+ The --enable-build-with-cxx configure option is now enabled by
+ default. One must now explicitly configure with
+ --disable-build-with-cxx in order to build with a C compiler. This
+ option will be removed in a future release.
+
+* GDBserver now supports recording btrace without maintaining an active
+ GDB connection.
+
+* GDB now supports a negative repeat count in the 'x' command to examine
+ memory backward from the given address. For example:
+
+ (gdb) bt
+ #0 Func1 (n=42, p=0x40061c "hogehoge") at main.cpp:4
+ #1 0x400580 in main (argc=1, argv=0x7fffffffe5c8) at main.cpp:8
+ (gdb) x/-5i 0x0000000000400580
+ 0x40056a <main(int, char**)+8>: mov %edi,-0x4(%rbp)
+ 0x40056d <main(int, char**)+11>: mov %rsi,-0x10(%rbp)
+ 0x400571 <main(int, char**)+15>: mov $0x40061c,%esi
+ 0x400576 <main(int, char**)+20>: mov $0x2a,%edi
+ 0x40057b <main(int, char**)+25>:
+ callq 0x400536 <Func1(int, char const*)>
+
+* Fortran: Support structures with fields of dynamic types and
+ arrays of dynamic types.
+
+* The symbol dumping maintenance commands have new syntax.
+maint print symbols [-pc address] [--] [filename]
+maint print symbols [-objfile objfile] [-source source] [--] [filename]
+maint print psymbols [-objfile objfile] [-pc address] [--] [filename]
+maint print psymbols [-objfile objfile] [-source source] [--] [filename]
+maint print msymbols [-objfile objfile] [--] [filename]
+
+* GDB now supports multibit bitfields and enums in target register
+ descriptions.
+
+* New Python-based convenience function $_as_string(val), which returns
+ the textual representation of a value. This function is especially
+ useful to obtain the text label of an enum value.
+
+* Intel MPX bound violation handling.
+
+ Segmentation faults caused by a Intel MPX boundary violation
+ now display the kind of violation (upper or lower), the memory
+ address accessed and the memory bounds, along with the usual
+ signal received and code location.
+
+ For example:
+
+ Program received signal SIGSEGV, Segmentation fault
+ Upper bound violation while accessing address 0x7fffffffc3b3
+ Bounds: [lower = 0x7fffffffc390, upper = 0x7fffffffc3a3]
+ 0x0000000000400d7c in upper () at i386-mpx-sigsegv.c:68
+
+* Rust language support.
+ GDB now supports debugging programs written in the Rust programming
+ language. See https://www.rust-lang.org/ for more information about
+ Rust.
+
+* Support for running interpreters on specified input/output devices
+
+ GDB now supports a new mechanism that allows frontends to provide
+ fully featured GDB console views, as a better alternative to
+ building such views on top of the "-interpreter-exec console"
+ command. See the new "new-ui" command below. With that command,
+ frontends can now start GDB in the traditional command-line mode
+ running in an embedded terminal emulator widget, and create a
+ separate MI interpreter running on a specified i/o device. In this
+ way, GDB handles line editing, history, tab completion, etc. in the
+ console all by itself, and the GUI uses the separate MI interpreter
+ for its own control and synchronization, invisible to the command
+ line.
+
+* The "catch syscall" command catches groups of related syscalls.
+
+ The "catch syscall" command now supports catching a group of related
+ syscalls using the 'group:' or 'g:' prefix.
+
+* New commands
+
+skip -file file
+skip -gfile file-glob-pattern
+skip -function function
+skip -rfunction regular-expression
+ A generalized form of the skip command, with new support for
+ glob-style file names and regular expressions for function names.
+ Additionally, a file spec and a function spec may now be combined.
+
+maint info line-table REGEXP
+ Display the contents of GDB's internal line table data struture.
+
+maint selftest
+ Run any GDB unit tests that were compiled in.
+
+new-ui INTERP TTY
+ Start a new user interface instance running INTERP as interpreter,
+ using the TTY file for input/output.
+
+* Python Scripting
+
+ ** gdb.Breakpoint objects have a new attribute "pending", which
+ indicates whether the breakpoint is pending.
+ ** Three new breakpoint-related events have been added:
+ gdb.breakpoint_created, gdb.breakpoint_modified, and
+ gdb.breakpoint_deleted.
+
+signal-event EVENTID
+ Signal ("set") the given MS-Windows event object. This is used in
+ conjunction with the Windows JIT debugging (AeDebug) support, where
+ the OS suspends a crashing process until a debugger can attach to
+ it. Resuming the crashing process, in order to debug it, is done by
+ signalling an event.
+
+* Support for tracepoints and fast tracepoints on s390-linux and s390x-linux
+ was added in GDBserver, including JIT compiling fast tracepoint's
+ conditional expression bytecode into native code.
+
+* Support for various remote target protocols and ROM monitors has
+ been removed:
+
+ target m32rsdi Remote M32R debugging over SDI
+ target mips MIPS remote debugging protocol
+ target pmon PMON ROM monitor
+ target ddb NEC's DDB variant of PMON for Vr4300
+ target rockhopper NEC RockHopper variant of PMON
+ target lsi LSI variant of PMO
+
+* Support for tracepoints and fast tracepoints on powerpc-linux,
+ powerpc64-linux, and powerpc64le-linux was added in GDBserver,
+ including JIT compiling fast tracepoint's conditional expression
+ bytecode into native code.
+
+* MI async record =record-started now includes the method and format used for
+ recording. For example:
+
+ =record-started,thread-group="i1",method="btrace",format="bts"
+
+* MI async record =thread-selected now includes the frame field. For example:
+
+ =thread-selected,id="3",frame={level="0",addr="0x00000000004007c0"}
+
+* New targets
+
+Andes NDS32 nds32*-*-elf
+
+*** Changes in GDB 7.11
+
+* GDB now supports debugging kernel-based threads on FreeBSD.
+
+* Per-inferior thread numbers
+
+ Thread numbers are now per inferior instead of global. If you're
+ debugging multiple inferiors, GDB displays thread IDs using a
+ qualified INF_NUM.THR_NUM form. For example:
+
+ (gdb) info threads
+ Id Target Id Frame
+ 1.1 Thread 0x7ffff7fc2740 (LWP 8155) (running)
+ 1.2 Thread 0x7ffff7fc1700 (LWP 8168) (running)
+ * 2.1 Thread 0x7ffff7fc2740 (LWP 8157) (running)
+ 2.2 Thread 0x7ffff7fc1700 (LWP 8190) (running)
+
+ As consequence, thread numbers as visible in the $_thread
+ convenience variable and in Python's InferiorThread.num attribute
+ are no longer unique between inferiors.
+
+ GDB now maintains a second thread ID per thread, referred to as the
+ global thread ID, which is the new equivalent of thread numbers in
+ previous releases. See also $_gthread below.
+
+ For backwards compatibility, MI's thread IDs always refer to global
+ IDs.
+
+* Commands that accept thread IDs now accept the qualified
+ INF_NUM.THR_NUM form as well. For example:
+
+ (gdb) thread 2.1
+ [Switching to thread 2.1 (Thread 0x7ffff7fc2740 (LWP 8157))] (running)
+ (gdb)
+
+* In commands that accept a list of thread IDs, you can now refer to
+ all threads of an inferior using a star wildcard. GDB accepts
+ "INF_NUM.*", to refer to all threads of inferior INF_NUM, and "*" to
+ refer to all threads of the current inferior. For example, "info
+ threads 2.*".
+
+* You can use "info threads -gid" to display the global thread ID of
+ all threads.
+
+* The new convenience variable $_gthread holds the global number of
+ the current thread.
+
+* The new convenience variable $_inferior holds the number of the
+ current inferior.
+
+* GDB now displays the ID and name of the thread that hit a breakpoint
+ or received a signal, if your program is multi-threaded. For
+ example:
+
+ Thread 3 "bar" hit Breakpoint 1 at 0x40087a: file program.c, line 20.
+ Thread 1 "main" received signal SIGINT, Interrupt.
+
+* Record btrace now supports non-stop mode.
* Support for tracepoints on aarch64-linux was added in GDBserver.
+* The 'record instruction-history' command now indicates speculative execution
+ when using the Intel Processor Trace recording format.
+
+* GDB now allows users to specify explicit locations, bypassing
+ the linespec parser. This feature is also available to GDB/MI
+ clients.
+
+* Multi-architecture debugging is supported on AArch64 GNU/Linux.
+ GDB now is able to debug both AArch64 applications and ARM applications
+ at the same time.
+
+* Support for fast tracepoints on aarch64-linux was added in GDBserver,
+ including JIT compiling fast tracepoint's conditional expression bytecode
+ into native code.
+
+* GDB now supports displaced stepping on AArch64 GNU/Linux.
+
+* "info threads", "info inferiors", "info display", "info checkpoints"
+ and "maint info program-spaces" now list the corresponding items in
+ ascending ID order, for consistency with all other "info" commands.
+
+* In Ada, the overloads selection menu has been enhanced to display the
+ parameter types and the return types for the matching overloaded subprograms.
+
+* New commands
+
+maint set target-non-stop (on|off|auto)
+maint show target-non-stop
+ Control whether GDB targets always operate in non-stop mode even if
+ "set non-stop" is "off". The default is "auto", meaning non-stop
+ mode is enabled if supported by the target.
+
+maint set bfd-sharing
+maint show bfd-sharing
+ Control the reuse of bfd objects.
+
+set debug bfd-cache
+show debug bfd-cache
+ Control display of debugging info regarding bfd caching.
+
+set debug fbsd-lwp
+show debug fbsd-lwp
+ Control display of debugging info regarding FreeBSD threads.
+
+set remote multiprocess-extensions-packet
+show remote multiprocess-extensions-packet
+ Set/show the use of the remote protocol multiprocess extensions.
+
+set remote thread-events
+show remote thread-events
+ Set/show the use of thread create/exit events.
+
+set ada print-signatures on|off
+show ada print-signatures"
+ Control whether parameter types and return types are displayed in overloads
+ selection menus. It is activaled (@code{on}) by default.
+
+set max-value-size
+show max-value-size
+ Controls the maximum size of memory, in bytes, that GDB will
+ allocate for value contents. Prevents incorrect programs from
+ causing GDB to allocate overly large buffers. Default is 64k.
+
+* The "disassemble" command accepts a new modifier: /s.
+ It prints mixed source+disassembly like /m with two differences:
+ - disassembled instructions are now printed in program order, and
+ - and source for all relevant files is now printed.
+ The "/m" option is now considered deprecated: its "source-centric"
+ output hasn't proved useful in practice.
+
+* The "record instruction-history" command accepts a new modifier: /s.
+ It behaves exactly like /m and prints mixed source+disassembly.
+
+* The "set scheduler-locking" command supports a new mode "replay".
+ It behaves like "off" in record mode and like "on" in replay mode.
+
+* Support for various ROM monitors has been removed:
+
+ target dbug dBUG ROM monitor for Motorola ColdFire
+ target picobug Motorola picobug monitor
+ target dink32 DINK32 ROM monitor for PowerPC
+ target m32r Renesas M32R/D ROM monitor
+ target mon2000 mon2000 ROM monitor
+ target ppcbug PPCBUG ROM monitor for PowerPC
+
+* Support for reading/writing memory and extracting values on architectures
+ whose memory is addressable in units of any integral multiple of 8 bits.
+
+* New remote packets
+
+exec stop reason
+ Indicates that an exec system call was executed.
+
+exec-events feature in qSupported
+ The qSupported packet allows GDB to request support for exec
+ events using the new 'gdbfeature' exec-event, and the qSupported
+ response can contain the corresponding 'stubfeature'. Set and
+ show commands can be used to display whether these features are enabled.
+
+vCtrlC
+ Equivalent to interrupting with the ^C character, but works in
+ non-stop mode.
+
+thread created stop reason (T05 create:...)
+ Indicates that the thread was just created and is stopped at entry.
+
+thread exit stop reply (w exitcode;tid)
+ Indicates that the thread has terminated.
+
+QThreadEvents
+ Enables/disables thread create and exit event reporting. For
+ example, this is used in non-stop mode when GDB stops a set of
+ threads and synchronously waits for the their corresponding stop
+ replies. Without exit events, if one of the threads exits, GDB
+ would hang forever not knowing that it should no longer expect a
+ stop for that same thread.
+
+N stop reply
+ Indicates that there are no resumed threads left in the target (all
+ threads are stopped). The remote stub reports support for this stop
+ reply to GDB's qSupported query.
+
+QCatchSyscalls
+ Enables/disables catching syscalls from the inferior process.
+ The remote stub reports support for this packet to GDB's qSupported query.
+
+syscall_entry stop reason
+ Indicates that a syscall was just called.
+
+syscall_return stop reason
+ Indicates that a syscall just returned.
+
+* Extended-remote exec events
+
+ ** GDB now has support for exec events on extended-remote Linux targets.
+ For such targets with Linux kernels 2.5.46 and later, this enables
+ follow-exec-mode and exec catchpoints.
+
+set remote exec-event-feature-packet
+show remote exec-event-feature-packet
+ Set/show the use of the remote exec event feature.
+
+ * Thread names in remote protocol
+
+ The reply to qXfer:threads:read may now include a name attribute for each
+ thread.
+
+* Target remote mode fork and exec events
+
+ ** GDB now has support for fork and exec events on target remote mode
+ Linux targets. For such targets with Linux kernels 2.5.46 and later,
+ this enables follow-fork-mode, detach-on-fork, follow-exec-mode, and
+ fork and exec catchpoints.
+
+* Remote syscall events
+
+ ** GDB now has support for catch syscall on remote Linux targets,
+ currently enabled on x86/x86_64 architectures.
+
+set remote catch-syscall-packet
+show remote catch-syscall-packet
+ Set/show the use of the remote catch syscall feature.
+
+* MI changes
+
+ ** The -var-set-format command now accepts the zero-hexadecimal
+ format. It outputs data in hexadecimal format with zero-padding on the
+ left.
+
+* Python Scripting
+
+ ** gdb.InferiorThread objects have a new attribute "global_num",
+ which refers to the thread's global thread ID. The existing
+ "num" attribute now refers to the thread's per-inferior number.
+ See "Per-inferior thread numbers" above.
+ ** gdb.InferiorThread objects have a new attribute "inferior", which
+ is the Inferior object the thread belongs to.
+
*** Changes in GDB 7.10
* Support for process record-replay and reverse debugging on aarch64*-linux*
show mpx bound
set mpx bound on i386 and amd64
- Support for bound table investigation on Intel(R) MPX enabled applications.
+ Support for bound table investigation on Intel MPX enabled applications.
record btrace pt
record pt
- Start branch trace recording using Intel(R) Processor Trace format.
+ Start branch trace recording using Intel Processor Trace format.
maint info btrace
Print information about branch tracing internals.
set|show record btrace pt buffer-size
Set and show the size of the ring buffer used for branch tracing in
- Intel(R) Processor Trace format.
+ Intel Processor Trace format.
The obtained size may differ from the requested size. Use "info
record" to see the obtained buffer size.
Set the requested ring buffer size for branch tracing in BTS format.
Qbtrace:pt
- Enable Intel(R) Procesor Trace-based branch tracing for the current
+ Enable Intel Procesor Trace-based branch tracing for the current
process. The remote stub reports support for this packet to GDB's
qSupported query.
Qbtrace-conf:pt:size
- Set the requested ring buffer size for branch tracing in Intel(R) Processor
+ Set the requested ring buffer size for branch tracing in Intel Processor
Trace format.
swbreak stop reason
--with-intel-pt
This configure option allows the user to build GDB with support for
- Intel(R) Processor Trace (default: auto). This requires libipt.
+ Intel Processor Trace (default: auto). This requires libipt.
--with-libipt-prefix=PATH
Specify the path to the version of libipt that GDB should use.
can be used to launch native programs even when "set
auto-connect-native-target" is set to off.
-* GDB now supports access to Intel(R) MPX registers on GNU/Linux.
+* GDB now supports access to Intel MPX registers on GNU/Linux.
-* Support for Intel(R) AVX-512 registers on GNU/Linux.
- Support displaying and modifying Intel(R) AVX-512 registers
+* Support for Intel AVX-512 registers on GNU/Linux.
+ Support displaying and modifying Intel AVX-512 registers
$zmm0 - $zmm31 and $k0 - $k7 on GNU/Linux.
* New remote packets