What has changed in GDB?
(Organized release by release)
-*** Changes since GDB 7.11
+*** Changes since GDB 8.0
+
+* New "--readnever" command line option instructs GDB to not read each
+ symbol file's symbolic debug information. This makes startup faster
+ but at the expense of not being able to perform symbolic debugging.
+ This option is intended for use cases where symbolic debugging will
+ not be used, e.g., when you only need to dump the debuggee's core.
+
+* GDB now uses the GNU MPFR library, if available, to emulate target
+ floating-point arithmetic during expression evaluation when the target
+ uses different floating-point formats than the host. At least version
+ 3.1 of GNU MPFR is required.
+
+* GDB now supports access to the guarded-storage-control registers and the
+ software-based guarded-storage broadcast control registers on IBM z14.
+
+* On Unix systems, GDB now supports transmitting environment variables
+ that are to be set or unset to GDBserver. These variables will
+ affect the environment to be passed to the remote inferior.
+
+ To inform GDB of environment variables that are to be transmitted to
+ GDBserver, use the "set environment" command. Only user set
+ environment variables are sent to GDBserver.
+
+ To inform GDB of environment variables that are to be unset before
+ the remote inferior is started by the GDBserver, use the "unset
+ environment" command.
+
+* Completion improvements
+
+ ** GDB can now complete function parameters in linespecs and
+ explicit locations without quoting. When setting breakpoints,
+ quoting around functions names to help with TAB-completion is
+ generally no longer necessary. For example, this now completes
+ correctly:
+
+ (gdb) b function(in[TAB]
+ (gdb) b function(int)
+
+ Related, GDB is no longer confused with completing functions in
+ C++ anonymous namespaces:
+
+ (gdb) b (anon[TAB]
+ (gdb) b (anonymous namespace)::[TAB][TAB]
+ (anonymous namespace)::a_function()
+ (anonymous namespace)::b_function()
+
+ ** GDB now has much improved linespec and explicit locations TAB
+ completion support, that better understands what you're
+ completing and offers better suggestions. For example, GDB no
+ longer offers data symbols as possible completions when you're
+ setting a breakpoint.
+
+ ** GDB now TAB-completes label symbol names.
+
+ ** The "complete" command now mimics TAB completion accurately.
+
+* Breakpoints on C++ functions are now set on all scopes by default
+
+ By default, breakpoints on functions/methods are now interpreted as
+ specifying all functions with the given name ignoring missing
+ leading scopes (namespaces and classes).
+
+ For example, assuming a C++ program with symbols named:
+
+ A::B::func()
+ B::func()
+
+ both commands "break func()" and "break B::func()" set a breakpoint
+ on both symbols.
+
+ You can use the new flag "-qualified" to override this. This makes
+ GDB interpret the specified function name as a complete
+ fully-qualified name instead. For example, using the same C++
+ program, the "break -q B::func" command sets a breakpoint on
+ "B::func", only.
+
+* Breakpoints on functions marked with C++ ABI tags
+
+ GDB can now set breakpoints on functions marked with C++ ABI tags
+ (e.g., [abi:cxx11]). See here for a description of ABI tags:
+ https://developers.redhat.com/blog/2015/02/05/gcc5-and-the-c11-abi/
+
+ Functions with a C++11 abi tag are demangled/displayed like this:
+
+ function[abi:cxx11](int)
+ ^^^^^^^^^^^
+
+ You can now set a breakpoint on such functions simply as if they had
+ no tag, like:
+
+ (gdb) b function(int)
+
+ Or if you need to disambiguate between tags, like:
+
+ (gdb) b function[abi:other_tag](int)
+
+ Tab completion was adjusted accordingly as well.
+
+* Python Scripting
+
+ ** New events gdb.new_inferior, gdb.inferior_deleted, and
+ gdb.new_thread are emitted. See the manual for further
+ description of these.
+
+ ** A new command, "rbreak" has been added to the Python API. This
+ command allows the setting of a large number of breakpoints via a
+ regex pattern in Python. See the manual for further details.
+
+* New features in the GDB remote stub, GDBserver
+
+ ** GDBserver is now able to start inferior processes with a
+ specified initial working directory.
+
+ The user can set the desired working directory to be used from
+ GDB using the new "set cwd" command.
+
+ ** New "--selftest" command line option runs some GDBserver self
+ tests. These self tests are disabled in releases.
+
+ ** On Unix systems, GDBserver now does globbing expansion and variable
+ substitution in inferior command line arguments.
+
+ This is done by starting inferiors using a shell, like GDB does.
+ See "set startup-with-shell" in the user manual for how to disable
+ this from GDB when using "target extended-remote". When using
+ "target remote", you can disable the startup with shell by using the
+ new "--no-startup-with-shell" GDBserver command line option.
+
+ ** On Unix systems, GDBserver now supports receiving environment
+ variables that are to be set or unset from GDB. These variables
+ will affect the environment to be passed to the inferior.
+
+* When catching an Ada exception raised with a message, GDB now prints
+ the message in the catchpoint hit notification. In GDB/MI mode, that
+ information is provided as an extra field named "exception-message"
+ in the *stopped notification.
+
+* New remote packets
+
+QEnvironmentHexEncoded
+ Inform GDBserver of an environment variable that is to be passed to
+ the inferior when starting it.
+
+QEnvironmentUnset
+ Inform GDBserver of an environment variable that is to be unset
+ before starting the remote inferior.
+
+QEnvironmentReset
+ Inform GDBserver that the environment should be reset (i.e.,
+ user-set environment variables should be unset).
+
+QStartupWithShell
+ Indicates whether the inferior must be started with a shell or not.
+
+QSetWorkingDir
+ Tell GDBserver that the inferior to be started should use a specific
+ working directory.
+
+* The "maintenance print c-tdesc" command now takes an optional
+ argument which is the file name of XML target description.
+
+* The "maintenance selftest" command now takes an optional argument to
+ filter the tests to be run.
+
+* The "enable", and "disable" commands now accept a range of
+ breakpoint locations, e.g. "enable 1.3-5".
+
+* New commands
+
+set|show cwd
+ Set and show the current working directory for the inferior.
+
+set|show compile-gcc
+ Set and show compilation command used for compiling and injecting code
+ with the 'compile' commands.
+
+set debug separate-debug-file
+show debug separate-debug-file
+ Control the display of debug output about separate debug file search.
+
+maint info selftests
+ List the registered selftests.
+
+starti
+ Start the debugged program stopping at the first instruction.
+
+* TUI Single-Key mode now supports two new shortcut keys: `i' for stepi and
+ `o' for nexti.
+
+* Safer/improved support for debugging with no debug info
+
+ GDB no longer assumes functions with no debug information return
+ 'int'.
+
+ This means that GDB now refuses to call such functions unless you
+ tell it the function's type, by either casting the call to the
+ declared return type, or by casting the function to a function
+ pointer of the right type, and calling that:
+
+ (gdb) p getenv ("PATH")
+ 'getenv' has unknown return type; cast the call to its declared return type
+ (gdb) p (char *) getenv ("PATH")
+ $1 = 0x7fffffffe "/usr/local/bin:/"...
+ (gdb) p ((char * (*) (const char *)) getenv) ("PATH")
+ $2 = 0x7fffffffe "/usr/local/bin:/"...
+
+ Similarly, GDB no longer assumes that global variables with no debug
+ info have type 'int', and refuses to print the variable's value
+ unless you tell it the variable's type:
+
+ (gdb) p var
+ 'var' has unknown type; cast it to its declared type
+ (gdb) p (float) var
+ $3 = 3.14
+
+* New native configurations
+
+FreeBSD/aarch64 aarch64*-*-freebsd*
+FreeBSD/arm arm*-*-freebsd*
+
+* New targets
+
+FreeBSD/aarch64 aarch64*-*-freebsd*
+FreeBSD/arm arm*-*-freebsd*
+
+* Removed targets and native configurations
+
+Solaris 2.0-9 i?86-*-solaris2.[0-9], sparc*-*-solaris2.[0-9]
+
+*** Changes in GDB 8.0
+
+* 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
+
+* Removed targets and native configurations
+
+Alpha running FreeBSD alpha*-*-freebsd*
+Alpha running GNU/kFreeBSD alpha*-*-kfreebsd*-gnu
+
+* New commands
+
+flash-erase
+ Erases all the flash memory regions reported by the target.
+
+maint print arc arc-instruction address
+ Print internal disassembler information about instruction at a given address.
+
+* New options
+
+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.
+
+* 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".
+
+*** 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
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
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.
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:1 [;SYSNO]...
-QCatchSyscalls:0
- Enable ("QCatchSyscalls:1") or disable ("QCatchSyscalls:0")
- catching syscalls from the inferior process.
+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.
-QCatchSyscalls:1 in qSupported
- The qSupported packet may now include QCatchSyscalls:1 in the reply
- to indicate support for catching syscalls.
-
* Extended-remote exec events
** GDB now has support for exec events on extended-remote Linux targets.