What has changed in GDB?
(Organized release by release)
-*** Changes since GDB 7.9
+*** 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.
+
+*** 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*
targets has been added. GDB now supports recording of A64 instruction set
including advance SIMD instructions.
+* Support for Sun's version of the "stabs" debug file format has been removed.
+
* GDB now honors the content of the file /proc/PID/coredump_filter
(PID is the process ID) on GNU/Linux systems. This file can be used
to specify the types of memory mappings that will be included in a
* The HISTSIZE environment variable is no longer read when determining
the size of GDB's command history. GDB now instead reads the dedicated
- GDBHISTSIZE environment variable.
+ GDBHISTSIZE environment variable. Setting GDBHISTSIZE to "-1" or to "" now
+ disables truncation of command history. Non-numeric values of GDBHISTSIZE
+ are ignored.
* Guile Scripting
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 Processor Trace format.
+
+maint info btrace
+ Print information about branch tracing internals.
+
+maint btrace packet-history
+ Print the raw branch tracing data.
+
+maint btrace clear-packet-history
+ Discard the stored raw branch tracing data.
+
+maint btrace clear
+ Discard all branch tracing data. It will be fetched and processed
+ anew by the next "record" command.
* New options
to avoid generating large completion lists, the computation of
which can cause the debugger to become temporarily unresponsive.
+set history remove-duplicates
+show history remove-duplicates
+ Control the removal of duplicate history entries.
+
maint set symbol-cache-size
maint show symbol-cache-size
Control the size of the symbol cache.
show debug linux-namespaces
Control display of debugging info regarding Linux namespaces.
+set|show record btrace pt buffer-size
+ Set and show the size of the ring buffer used for branch tracing in
+ Intel Processor Trace format.
+ The obtained size may differ from the requested size. Use "info
+ record" to see the obtained buffer size.
+
+maint set|show btrace pt skip-pad
+ Set and show whether PAD packets are skipped when computing the
+ packet history.
+
* The command 'thread apply all' can now support new option '-ascending'
to call its specified command for all threads in ascending order.
Qbtrace-conf:bts:size
Set the requested ring buffer size for branch tracing in BTS format.
+Qbtrace:pt
+ 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 Processor
+ Trace format.
+
swbreak stop reason
Indicates a memory breakpoint instruction was executed, irrespective
of whether it was GDB that planted the breakpoint or the breakpoint
HP/PA running HP-UX hppa*-*-hpux*
Itanium running HP-UX ia64-*-hpux*
+* New configure options
+
+--with-intel-pt
+ This configure option allows the user to build GDB with support for
+ Intel Processor Trace (default: auto). This requires libipt.
+
+--with-libipt-prefix=PATH
+ Specify the path to the version of libipt that GDB should use.
+ $PATH/include should contain the intel-pt.h header and
+ $PATH/lib should contain the libipt.so library.
+
*** Changes in GDB 7.9.1
* Python Scripting
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