What has changed in GDB?
(Organized release by release)
-*** Changes since GDB 6.6
+*** Changes since GDB 6.8
+
+* 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.
+
+* 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".
+
+* GDB now supports the token-splicing (##) and stringification (#)
+operators when expanding macros. It also supports variable-arity
+macros.
+
+* New remote packets
+
+qSearch:memory:
+ Search memory for a sequence of bytes.
+
+QStartNoAckMode
+ 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.
+
+* 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.
+
+* The "disassemble" command now supports an optional /m modifier to print mixed
+source+assembly.
+
+* 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.
+
+* 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.
+
+* 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.
+
+* Python scripting
+
+ GDB now has support for scripting using Python. Whether this is
+ available is determined at configure time.
+
+* New commands
+
+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.
+
+set print symbol-loading
+show print symbol-loading
+ Control printing of symbol loading messages.
+
+set debug timestamp
+show debug timestamp
+ Display timestamps with GDB debugging output.
+
+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 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.
+
+macro define
+macro list
+macro undef
+ These allow macros to be defined, undefined, and listed
+ interactively.
+
+* New targets
+
+x86 DICOS i[34567]86-*-dicos*
+
+*** 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
+include:
+ - 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
+process.
+
+* 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
+
+-target-file-put
+-target-file-get
+-target-file-delete
+ Transfer files to and from a remote target, and delete remote files.
+
+* New remote packets
+
+vFile:open:
+vFile:close:
+vFile:pread:
+vFile:pwrite:
+vFile:unlink:
+ Open, close, read, write, and delete files on the remote system.
+
+vAttach
+ Attach to an existing process on the remote system, in extended-remote
+ mode.
+
+vRun
+ 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. (http://scan.coverity.com).
+
+* 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.
target's overall architecture. GDB can read a description from
a local file or over the remote serial protocol.
-* Arrays of explicitly SIGNED or UNSIGNED CHARs are now printed as arrays
- of numbers.
+* 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).
+only ARM, M68K, and MIPS).
* GDB and the GDB remote stub, gdbserver, now support the XScale
iWMMXt coprocessor.
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
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
+ architecture.
+
* New native configurations
OpenBSD/sh sh*-*openbsd*
Read an XML target description from the target, which describes its
features.
+qXfer:spu:read:
+qXfer:spu:write:
+ Read or write contents of an spufs file on the target system. These
+ packets are available only on the Cell/B.E. SPU architecture.
+
+qXfer:libraries:read:
+ 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.
+alpha*-*-osf1*
+alpha*-*-osf2*
d10v-*-*
hppa*-*-hiux*
i[34567]86-ncr-*
Various m68k-only ROM monitors.
+target hms
+target e7000
+target sh3
+target sh3e
+
+ Various Renesas ROM monitors and debugging interfaces for SH and
+ H8/300.
+
+target ocd
+
+ Support for a Macraigor serial interface to on-chip debugging.
+ GDB does not directly support the newer parallel or USB
+ interfaces.
+
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