What has changed in GDB?
(Organized release by release)
-*** Changes since GDB 8.0
+*** Changes since GDB 8.2
-* On Unix systems, GDBserver now does globbing expansion and variable
- substitution in inferior command line arguments.
+*** Changes in GDB 8.2
- 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.
+* The 'set disassembler-options' command now supports specifying options
+ for the MIPS target.
+
+* The 'symbol-file' command now accepts an '-o' option to add a relative
+ offset to all sections.
+
+* Similarly, the 'add-symbol-file' command also accepts an '-o' option to add
+ a relative offset to all sections, but it allows to override the load
+ address of individual sections using '-s'.
+
+* The 'add-symbol-file' command no longer requires the second argument
+ (address of the text section).
+
+* The endianness used with the 'set endian auto' mode in the absence of
+ an executable selected for debugging is now the last endianness chosen
+ either by one of the 'set endian big' and 'set endian little' commands
+ or by inferring from the last executable used, rather than the startup
+ default.
+
+* The pager now allows a "c" response, meaning to disable the pager
+ for the rest of the current command.
+
+* The commands 'info variables/functions/types' now show the source line
+ numbers of symbol definitions when available.
+
+* 'info proc' now works on running processes on FreeBSD systems and core
+ files created on FreeBSD systems.
+
+* C expressions can now use _Alignof, and C++ expressions can now use
+ alignof.
+
+* New commands
+
+set debug fbsd-nat
+show debug fbsd-nat
+ Control display of debugging info regarding the FreeBSD native target.
+
+set|show varsize-limit
+ This new setting allows the user to control the maximum size of Ada
+ objects being printed when those objects have a variable type,
+ instead of that maximum size being hardcoded to 65536 bytes.
+
+set|show record btrace cpu
+ Controls the processor to be used for enabling errata workarounds for
+ branch trace decode.
+
+maint check libthread-db
+ Run integrity checks on the current inferior's thread debugging
+ library
+
+maint set check-libthread-db (on|off)
+maint show check-libthread-db
+ Control whether to run integrity checks on inferior specific thread
+ debugging libraries as they are loaded. The default is not to
+ perform such checks.
+
+* Python API
+
+ ** Type alignment is now exposed via the "align" attribute of a gdb.Type.
+
+ ** The commands attached to a breakpoint can be set by assigning to
+ the breakpoint's "commands" field.
+
+ ** gdb.execute can now execute multi-line gdb commands.
+
+ ** The new functions gdb.convenience_variable and
+ gdb.set_convenience_variable can be used to get and set the value
+ of convenience variables.
+
+ ** A gdb.Parameter will no longer print the "set" help text on an
+ ordinary "set"; instead by default a "set" will be silent unless
+ the get_set_string method returns a non-empty string.
+
+* New targets
+
+RiscV ELF riscv*-*-elf
+
+* Removed targets and native configurations
+
+m88k running OpenBSD m88*-*-openbsd*
+SH-5/SH64 ELF sh64-*-elf*, SH-5/SH64 support in sh*
+SH-5/SH64 running GNU/Linux SH-5/SH64 support in sh*-*-linux*
+SH-5/SH64 running OpenBSD SH-5/SH64 support in sh*-*-openbsd*
+
+* Aarch64/Linux hardware watchpoints improvements
+
+ Hardware watchpoints on unaligned addresses are now properly
+ supported when running Linux kernel 4.10 or higher: read and access
+ watchpoints are no longer spuriously missed, and all watchpoints
+ lengths between 1 and 8 bytes are supported. On older kernels,
+ watchpoints set on unaligned addresses are no longer missed, with
+ the tradeoff that there is a possibility of false hits being
+ reported.
+
+* New configure options
+
+--enable-codesign=CERT
+ This can be used to invoke "codesign -s CERT" after building gdb.
+ This option is useful on macOS, where code signing is required for
+ gdb to work properly.
+
+*** Changes in GDB 8.1
+
+* GDB now supports dynamically creating arbitrary register groups specified
+ in XML target descriptions. This allows for finer grain grouping of
+ registers on systems with a large amount of registers.
+
+* The 'ptype' command now accepts a '/o' flag, which prints the
+ offsets and sizes of fields in a struct, like the pahole(1) tool.
+
+* 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.
+
+* New command line options (gcore)
+
+-a
+ Dump all memory mappings.
+
+* 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. A parameter has been added to the Python
+ gdb.Breakpoint constructor to achieve the same result when creating
+ a breakpoint from Python.
+
+* 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 function, "gdb.rbreak" has been added to the Python API.
+ This function allows the setting of a large number of breakpoints
+ via a regex pattern in Python. See the manual for further details.
+
+ ** Python breakpoints can now accept explicit locations. See the
+ manual for a further description of this feature.
+
+
+* 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.
+
+* Trait objects can now be inspected When debugging Rust code. This
+ requires compiler support which will appear in Rust 1.24.
* 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.
+set dump-excluded-mappings
+show dump-excluded-mappings
+ Control whether mappings marked with the VM_DONTDUMP flag should be
+ dumped when generating a core file.
+
+maint info selftests
+ List the registered selftests.
+
+starti
+ Start the debugged program stopping at the first instruction.
+
+set|show debug or1k
+ Control display of debugging messages related to OpenRISC targets.
+
+set|show print type nested-type-limit
+ Set and show the limit of nesting level for nested types that the
+ type printer will show.
+
* 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*
+OpenRISC ELF or1k*-*-elf
+
+* 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
List the shared libraries in the program. This is
equivalent to the CLI command "info shared".
+-catch-handlers
+ Catchpoints stopping the program when Ada exceptions are
+ handled. This is equivalent to the CLI command "catch handlers".
+
*** Changes in GDB 7.12
* GDB and GDBserver now build with a C++ compiler by default.
* 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
+catch handlers
+ Allows to break when an Ada exception is handled.
-QStartupWithShell
- Indicates whether the inferior must be started with a shell or not.
+* New remote packets
exec stop reason
Indicates that an exec system call was executed.