\input texinfo @c -*-texinfo-*-
-@c Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998,
-@c 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
-@c Free Software Foundation, Inc.
+@c Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
+@c 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
+@c 2010, 2011 Free Software Foundation, Inc.
@c
@c %**start of header
@c makeinfo ignores cmds prev to setfilename, so its arg cannot make use
Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
-under the terms of the GNU Free Documentation License, Version 1.1 or
+under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with the
Invariant Sections being ``Free Software'' and ``Free Software Needs
Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,''
* GDB Bugs:: Reporting bugs in @value{GDBN}
+@ifset SYSTEM_READLINE
+* Command Line Editing: (rluserman). Command Line Editing
+* Using History Interactively: (history). Using History Interactively
+@end ifset
+@ifclear SYSTEM_READLINE
* Command Line Editing:: Command Line Editing
* Using History Interactively:: Using History Interactively
+@end ifclear
* Formatting Documentation:: How to format and print @value{GDBN} documentation
* Installing GDB:: Installing GDB
* Maintenance Commands:: Maintenance Commands
For more information, see @ref{Supported Languages,,Supported Languages}.
For more information, see @ref{C,,C and C++}.
+Support for D is partial. For information on D, see
+@ref{D,,D}.
+
@cindex Modula-2
Support for Modula-2 is partial. For information on Modula-2, see
@ref{Modula-2,,Modula-2}.
+Support for OpenCL C is partial. For information on OpenCL C, see
+@ref{OpenCL C,,OpenCL C}.
+
@cindex Pascal
Debugging Pascal programs which use sets, subranges, file variables, or
nested functions does not currently work. @value{GDBN} does not support
command files specified with @samp{-x} (and all commands from
initialization files, if not inhibited with @samp{-n}). Exit with
nonzero status if an error occurs in executing the @value{GDBN} commands
-in the command files. Batch mode also disables pagination;
-@pxref{Screen Size} and acts as if @kbd{set confirm off} were in
-effect (@pxref{Messages/Warnings}).
+in the command files. Batch mode also disables pagination, sets unlimited
+terminal width and height @pxref{Screen Size}, and acts as if @kbd{set confirm
+off} were in effect (@pxref{Messages/Warnings}).
Batch mode may be useful for running @value{GDBN} as a filter, for
example to download and run a program on another computer; in order to
Run @value{GDBN} using @var{directory} as its working directory,
instead of the current directory.
+@item -data-directory @var{directory}
+@cindex @code{--data-directory}
+Run @value{GDBN} using @var{directory} as its data directory.
+The data directory is where @value{GDBN} searches for its
+auxiliary files. @xref{Data Files}.
+
@item -fullname
@itemx -f
@cindex @code{--fullname}
to the program you are debugging, in the directory where you invoke
@value{GDBN}.
+@item
+If the command line specified a program to debug, or a process to
+attach to, or a core file, @value{GDBN} loads any auto-loaded
+scripts provided for the program or for its loaded shared libraries.
+@xref{Auto-loading}.
+
+If you wish to disable the auto-loading during startup,
+you must do something like the following:
+
+@smallexample
+$ gdb -ex "set auto-load-scripts off" -ex "file myprogram"
+@end smallexample
+
+The following does not work because the auto-loading is turned off too late:
+
+@smallexample
+$ gdb -ex "set auto-load-scripts off" myprogram
+@end smallexample
+
@item
Reads command files specified by the @samp{-x} option. @xref{Command
Files}, for more details about @value{GDBN} command files.
@kindex detach inferior @var{infno}
@item detach inferior @var{infno}
Detach from the inferior identified by @value{GDBN} inferior number
-@var{infno}, and remove it from the inferior list.
+@var{infno}. Note that the inferior's entry still stays on the list
+of inferiors shown by @code{info inferiors}, but its Description will
+show @samp{<null>}.
@kindex kill inferior @var{infno}
@item kill inferior @var{infno}
Kill the inferior identified by @value{GDBN} inferior number
-@var{infno}, and remove it from the inferior list.
+@var{infno}. Note that the inferior's entry still stays on the list
+of inferiors shown by @code{info inferiors}, but its Description will
+show @samp{<null>}.
@end table
After the successful completion of a command such as @code{detach},
@smallexample
(@value{GDBP}) info threads
- 3 process 35 thread 27 0x34e5 in sigpause ()
- 2 process 35 thread 23 0x34e5 in sigpause ()
-* 1 process 35 thread 13 main (argc=1, argv=0x7ffffff8)
+ Id Target Id Frame
+ 3 process 35 thread 27 0x34e5 in sigpause ()
+ 2 process 35 thread 23 0x34e5 in sigpause ()
+* 1 process 35 thread 13 main (argc=1, argv=0x7ffffff8)
at threadtest.c:68
@end smallexample
-On HP-UX systems:
-
-@cindex debugging multithreaded programs (on HP-UX)
-@cindex thread identifier (GDB), on HP-UX
-For debugging purposes, @value{GDBN} associates its own thread
-number---a small integer assigned in thread-creation order---with each
-thread in your program.
-
-@cindex @code{New} @var{systag} message, on HP-UX
-@cindex thread identifier (system), on HP-UX
-@c FIXME-implementors!! It would be more helpful if the [New...] message
-@c included GDB's numeric thread handle, so you could just go to that
-@c thread without first checking `info threads'.
-Whenever @value{GDBN} detects a new thread in your program, it displays
-both @value{GDBN}'s thread number and the target system's identification for the thread with a message in the
-form @samp{[New @var{systag}]}. @var{systag} is a thread identifier
-whose form varies depending on the particular system. For example, on
-HP-UX, you see
-
-@smallexample
-[New thread 2 (system thread 26594)]
-@end smallexample
-
-@noindent
-when @value{GDBN} notices a new thread.
-
-@table @code
-@kindex info threads (HP-UX)
-@item info threads
-Display a summary of all threads currently in your
-program. @value{GDBN} displays for each thread (in this order):
-
-@enumerate
-@item the thread number assigned by @value{GDBN}
-
-@item the target system's thread identifier (@var{systag})
-
-@item the current stack frame summary for that thread
-@end enumerate
-
-@noindent
-An asterisk @samp{*} to the left of the @value{GDBN} thread number
-indicates the current thread.
-
-For example,
-@end table
-@c end table here to get a little more width for example
-
-@smallexample
-(@value{GDBP}) info threads
- * 3 system thread 26607 worker (wptr=0x7b09c318 "@@") \@*
- at quicksort.c:137
- 2 system thread 26606 0x7b0030d8 in __ksleep () \@*
- from /usr/lib/libc.2
- 1 system thread 27905 0x7b003498 in _brk () \@*
- from /usr/lib/libc.2
-@end smallexample
-
On Solaris, you can display more information about user threads with a
Solaris-specific command:
you selected, and its current stack frame summary:
@smallexample
-@c FIXME!! This example made up; find a @value{GDBN} w/threads and get real one
(@value{GDBP}) thread 2
-[Switching to process 35 thread 23]
-0x34e5 in sigpause ()
+[Switching to thread 2 (Thread 0xb7fdab70 (LWP 12747))]
+#0 some_function (ignore=0x0) at example.c:8
+8 printf ("hello\n");
@end smallexample
@noindent
@samp{Switching to} depends on your system's conventions for identifying
threads.
+@vindex $_thread@r{, convenience variable}
+The debugger convenience variable @samp{$_thread} contains the number
+of the current thread. You may find this useful in writing breakpoint
+conditional expressions, command scripts, and so forth. See
+@xref{Convenience Vars,, Convenience Variables}, for general
+information on convenience variables.
+
@kindex thread apply
@cindex apply command to several threads
-@item thread apply [@var{threadno}] [@var{all}] @var{command}
+@item thread apply [@var{threadno} | all] @var{command}
The @code{thread apply} command allows you to apply the named
@var{command} to one or more threads. Specify the numbers of the
threads that you want affected with the command argument
@kindex show libthread-db-search-path
@item show libthread-db-search-path
Display current libthread_db search path.
+
+@kindex set debug libthread-db
+@kindex show debug libthread-db
+@cindex debugging @code{libthread_db}
+@item set debug libthread-db
+@itemx show debug libthread-db
+Turns on or off display of @code{libthread_db}-related events.
+Use @code{1} to enable, @code{0} to disable.
@end table
@node Forks
* Disabling:: Disabling breakpoints
* Conditions:: Break conditions
* Break Commands:: Breakpoint command lists
+* Save Breakpoints:: How to save breakpoints in a file
* Error in Breakpoints:: ``Cannot insert breakpoints''
* Breakpoint-related Warnings:: ``Breakpoint address adjusted...''
@end menu
@kindex rbreak
@cindex regular expression
-@cindex breakpoints in functions matching a regexp
+@cindex breakpoints at functions matching a regexp
@cindex set breakpoints in many functions
@item rbreak @var{regex}
Set breakpoints on all functions matching the regular expression
(@value{GDBP}) rbreak .
@end smallexample
+@item rbreak @var{file}:@var{regex}
+If @code{rbreak} is called with a filename qualification, it limits
+the search for functions matching the given regular expression to the
+specified @var{file}. This can be used, for example, to set breakpoints on
+every function in a given file:
+
+@smallexample
+(@value{GDBP}) rbreak file.c:.
+@end smallexample
+
+The colon separating the filename qualifier from the regex may
+optionally be surrounded by spaces.
+
@kindex info breakpoints
@cindex @code{$_} and @code{info breakpoints}
@item info breakpoints @r{[}@var{n}@r{]}
@table @code
@kindex watch
-@item watch @var{expr} @r{[}thread @var{threadnum}@r{]}
+@item watch @r{[}-l@r{|}-location@r{]} @var{expr} @r{[}thread @var{threadnum}@r{]}
Set a watchpoint for an expression. @value{GDBN} will break when the
expression @var{expr} is written into by the program and its value
changes. The simplest (and the most popular) use of this command is
that watchpoints restricted to a single thread in this way only work
with Hardware Watchpoints.
+Ordinarily a watchpoint respects the scope of variables in @var{expr}
+(see below). The @code{-location} argument tells @value{GDBN} to
+instead watch the memory referred to by @var{expr}. In this case,
+@value{GDBN} will evaluate @var{expr}, take the address of the result,
+and watch the memory at that address. The type of the result is used
+to determine the size of the watched memory. If the expression's
+result does not have an address, then @value{GDBN} will print an
+error.
+
@kindex rwatch
-@item rwatch @var{expr} @r{[}thread @var{threadnum}@r{]}
+@item rwatch @r{[}-l@r{|}-location@r{]} @var{expr} @r{[}thread @var{threadnum}@r{]}
Set a watchpoint that will break when the value of @var{expr} is read
by the program.
@kindex awatch
-@item awatch @var{expr} @r{[}thread @var{threadnum}@r{]}
+@item awatch @r{[}-l@r{|}-location@r{]} @var{expr} @r{[}thread @var{threadnum}@r{]}
Set a watchpoint that will break when @var{expr} is either read from
or written into by the program.
@code{info break} (@pxref{Set Breaks}).
@end table
+If you watch for a change in a numerically entered address you need to
+dereference it, as the address itself is just a constant number which will
+never change. @value{GDBN} refuses to create a watchpoint that watches
+a never-changing value:
+
+@smallexample
+(@value{GDBP}) watch 0x600850
+Cannot watch constant value 0x600850.
+(@value{GDBP}) watch *(int *) 0x600850
+Watchpoint 1: *(int *) 6293584
+@end smallexample
+
@value{GDBN} sets a @dfn{hardware watchpoint} if possible. Hardware
watchpoints execute very quickly, and the debugger reports a change in
value at the exact instruction where the change occurs. If @value{GDBN}
end
@end smallexample
+@node Save Breakpoints
+@subsection How to save breakpoints to a file
+
+To save breakpoint definitions to a file use the @w{@code{save
+breakpoints}} command.
+
+@table @code
+@kindex save breakpoints
+@cindex save breakpoints to a file for future sessions
+@item save breakpoints [@var{filename}]
+This command saves all current breakpoint definitions together with
+their commands and ignore counts, into a file @file{@var{filename}}
+suitable for use in a later debugging session. This includes all
+types of breakpoints (breakpoints, watchpoints, catchpoints,
+tracepoints). To read the saved breakpoint definitions, use the
+@code{source} command (@pxref{Command Files}). Note that watchpoints
+with expressions involving local variables may fail to be recreated
+because it may not be possible to access the context where the
+watchpoint is valid anymore. Because the saved breakpoint definitions
+are simply a sequence of @value{GDBN} commands that recreate the
+breakpoints, you can edit the file in your favorite editing program,
+and remove the breakpoint definitions you're not interested in, or
+that can no longer be recreated.
+@end table
+
@c @ifclear BARETARGET
@node Error in Breakpoints
@subsection ``Cannot insert breakpoints''
* Background Execution:: Running your program asynchronously
* Thread-Specific Breakpoints:: Controlling breakpoints
* Interrupted System Calls:: GDB may interfere with system calls
+* Observer Mode:: GDB does not alter program behavior
@end menu
@node All-Stop Mode
When such an event happens, a system call in another thread may return
prematurely, even though your program does not appear to stop.
+@node Observer Mode
+@subsection Observer Mode
+
+If you want to build on non-stop mode and observe program behavior
+without any chance of disruption by @value{GDBN}, you can set
+variables to disable all of the debugger's attempts to modify state,
+whether by writing memory, inserting breakpoints, etc. These operate
+at a low level, intercepting operations from all commands.
+
+When all of these are set to @code{off}, then @value{GDBN} is said to
+be @dfn{observer mode}. As a convenience, the variable
+@code{observer} can be set to disable these, plus enable non-stop
+mode.
+
+Note that @value{GDBN} will not prevent you from making nonsensical
+combinations of these settings. For instance, if you have enabled
+@code{may-insert-breakpoints} but disabled @code{may-write-memory},
+then breakpoints that work by writing trap instructions into the code
+stream will still not be able to be placed.
+
+@table @code
+
+@kindex observer
+@item set observer on
+@itemx set observer off
+When set to @code{on}, this disables all the permission variables
+below (except for @code{insert-fast-tracepoints}), plus enables
+non-stop debugging. Setting this to @code{off} switches back to
+normal debugging, though remaining in non-stop mode.
+
+@item show observer
+Show whether observer mode is on or off.
+
+@kindex may-write-registers
+@item set may-write-registers on
+@itemx set may-write-registers off
+This controls whether @value{GDBN} will attempt to alter the values of
+registers, such as with assignment expressions in @code{print}, or the
+@code{jump} command. It defaults to @code{on}.
+
+@item show may-write-registers
+Show the current permission to write registers.
+
+@kindex may-write-memory
+@item set may-write-memory on
+@itemx set may-write-memory off
+This controls whether @value{GDBN} will attempt to alter the contents
+of memory, such as with assignment expressions in @code{print}. It
+defaults to @code{on}.
+
+@item show may-write-memory
+Show the current permission to write memory.
+
+@kindex may-insert-breakpoints
+@item set may-insert-breakpoints on
+@itemx set may-insert-breakpoints off
+This controls whether @value{GDBN} will attempt to insert breakpoints.
+This affects all breakpoints, including internal breakpoints defined
+by @value{GDBN}. It defaults to @code{on}.
+
+@item show may-insert-breakpoints
+Show the current permission to insert breakpoints.
+
+@kindex may-insert-tracepoints
+@item set may-insert-tracepoints on
+@itemx set may-insert-tracepoints off
+This controls whether @value{GDBN} will attempt to insert (regular)
+tracepoints at the beginning of a tracing experiment. It affects only
+non-fast tracepoints, fast tracepoints being under the control of
+@code{may-insert-fast-tracepoints}. It defaults to @code{on}.
+
+@item show may-insert-tracepoints
+Show the current permission to insert tracepoints.
+
+@kindex may-insert-fast-tracepoints
+@item set may-insert-fast-tracepoints on
+@itemx set may-insert-fast-tracepoints off
+This controls whether @value{GDBN} will attempt to insert fast
+tracepoints at the beginning of a tracing experiment. It affects only
+fast tracepoints, regular (non-fast) tracepoints being under the
+control of @code{may-insert-tracepoints}. It defaults to @code{on}.
+
+@item show may-insert-fast-tracepoints
+Show the current permission to insert fast tracepoints.
+
+@kindex may-interrupt
+@item set may-interrupt on
+@itemx set may-interrupt off
+This controls whether @value{GDBN} will attempt to interrupt or stop
+program execution. When this variable is @code{off}, the
+@code{interrupt} command will have no effect, nor will
+@kbd{Ctrl-c}. It defaults to @code{on}.
+
+@item show may-interrupt
+Show the current permission to interrupt or stop the program.
+
+@end table
@node Reverse Execution
@chapter Running programs backward
When the inferior process exits, or @value{GDBN} detaches from it,
process record and replay target will automatically stop itself.
+@kindex record save
+@item record save @var{filename}
+Save the execution log to a file @file{@var{filename}}.
+Default filename is @file{gdb_record.@var{process_id}}, where
+@var{process_id} is the process ID of the inferior.
+
+@kindex record restore
+@item record restore @var{filename}
+Restore the execution log from a file @file{@var{filename}}.
+File must have been created with @code{record save}.
+
@kindex set record insn-number-max
@item set record insn-number-max @var{limit}
Set the limit of instructions to be recorded. Default value is 200000.
@item show record stop-at-limit
Show the current setting of @code{stop-at-limit}.
+@kindex set record memory-query
+@item set record memory-query
+Control the behavior when @value{GDBN} is unable to record memory
+changes caused by an instruction. If ON, @value{GDBN} will query
+whether to stop the inferior in that case.
+
+If this option is OFF (the default), @value{GDBN} will automatically
+ignore the effect of such instructions on memory. Later, when
+@value{GDBN} replays this execution log, it will mark the log of this
+instruction as not accessible, and it will not affect the replay
+results.
+
+@kindex show record memory-query
+@item show record memory-query
+Show the current setting of @code{memory-query}.
+
@kindex info record
@item info record
Show various statistics about the state of process record and its
function name to avoid ambiguity when there are identically named
functions in different source files.
+@item @var{label}
+Specifies the line at which the label named @var{label} appears.
+@value{GDBN} searches for the label in the function corresponding to
+the currently selected stack frame. If there is no current selected
+stack frame (for instance, if the inferior is not running), then
+@value{GDBN} will not search for a label.
+
@item *@var{address}
Specifies the program address @var{address}. For line-oriented
commands, such as @code{list} and @code{edit}, this specifies a source
@c RET-repeat for @code{directory} is explicitly disabled, but since
@c repeating it would be a no-op we do not say that. (thanks to RMS)
+@item set directories @var{path-list}
+@kindex set directories
+Set the source path to @var{path-list}.
+@samp{$cdir:$cwd} are added if missing.
+
@item show directories
@kindex show directories
Print the source path: show which directories it contains.
command is a program counter value; @value{GDBN} dumps the function
surrounding this value. When two arguments are given, they should
be separated by a comma, possibly surrounded by whitespace. The
-arguments specify a range of addresses (first inclusive, second exclusive)
-to dump. In that case, the name of the function is also printed (since
-there could be several functions in the given range).
+arguments specify a range of addresses to dump, in one of two forms:
+
+@table @code
+@item @var{start},@var{end}
+the addresses from @var{start} (inclusive) to @var{end} (exclusive)
+@item @var{start},+@var{length}
+the addresses from @var{start} (inclusive) to
+@code{@var{start}+@var{length}} (exclusive).
+@end table
+
+@noindent
+When 2 arguments are specified, the name of the function is also
+printed (since there could be several functions in the given range).
The argument(s) can be any expression yielding a numeric value, such as
@samp{0x32c4}, @samp{&main+10} or @samp{$pc - 8}.
End of assembler dump.
@end smallexample
+Here is another example showing raw instructions in hex for AMD x86-64,
+
+@smallexample
+(gdb) disas /r 0x400281,+10
+Dump of assembler code from 0x400281 to 0x40028b:
+ 0x0000000000400281: 38 36 cmp %dh,(%rsi)
+ 0x0000000000400283: 2d 36 34 2e 73 sub $0x732e3436,%eax
+ 0x0000000000400288: 6f outsl %ds:(%rsi),(%dx)
+ 0x0000000000400289: 2e 32 00 xor %cs:(%rax),%al
+End of assembler dump.
+@end smallexample
+
Some architectures have more than one commonly-used set of instruction
mnemonics or other syntax.
* Memory:: Examining memory
* Auto Display:: Automatic display
* Print Settings:: Print settings
+* Pretty Printing:: Python pretty printing
* Value History:: Value history
* Convenience Vars:: Convenience variables
* Registers:: Registers
@end table
Each time you specify a unit size with @code{x}, that size becomes the
-default unit the next time you use @code{x}. (For the @samp{s} and
-@samp{i} formats, the unit size is ignored and is normally not written.)
+default unit the next time you use @code{x}. For the @samp{i} format,
+the unit size is ignored and is normally not written. For the @samp{s} format,
+the unit size defaults to @samp{b}, unless it is explicitly given.
+Use @kbd{x /hs} to display 16-bit char strings and @kbd{x /ws} to display
+32-bit strings. The next use of @kbd{x /s} will again display 8-bit strings.
+Note that the results depend on the programming language of the
+current compilation unit. If the language is C, the @samp{s}
+modifier will use the UTF-16 encoding while @samp{w} will use
+UTF-32. The encoding is set by the programming language and cannot
+be altered.
@item @var{addr}, starting display address
@var{addr} is the address where you want @value{GDBN} to begin displaying
Show whether C@t{++} virtual function tables are pretty printed, or not.
@end table
+@node Pretty Printing
+@section Pretty Printing
+
+@value{GDBN} provides a mechanism to allow pretty-printing of values using
+Python code. It greatly simplifies the display of complex objects. This
+mechanism works for both MI and the CLI.
+
+@menu
+* Pretty-Printer Introduction:: Introduction to pretty-printers
+* Pretty-Printer Example:: An example pretty-printer
+* Pretty-Printer Commands:: Pretty-printer commands
+@end menu
+
+@node Pretty-Printer Introduction
+@subsection Pretty-Printer Introduction
+
+When @value{GDBN} prints a value, it first sees if there is a pretty-printer
+registered for the value. If there is then @value{GDBN} invokes the
+pretty-printer to print the value. Otherwise the value is printed normally.
+
+Pretty-printers are normally named. This makes them easy to manage.
+The @samp{info pretty-printer} command will list all the installed
+pretty-printers with their names.
+If a pretty-printer can handle multiple data types, then its
+@dfn{subprinters} are the printers for the individual data types.
+Each such subprinter has its own name.
+The format of the name is @var{printer-name};@var{subprinter-name}.
+
+Pretty-printers are installed by @dfn{registering} them with @value{GDBN}.
+Typically they are automatically loaded and registered when the corresponding
+debug information is loaded, thus making them available without having to
+do anything special.
+
+There are three places where a pretty-printer can be registered.
+
+@itemize @bullet
+@item
+Pretty-printers registered globally are available when debugging
+all inferiors.
+
+@item
+Pretty-printers registered with a program space are available only
+when debugging that program.
+@xref{Progspaces In Python}, for more details on program spaces in Python.
+
+@item
+Pretty-printers registered with an objfile are loaded and unloaded
+with the corresponding objfile (e.g., shared library).
+@xref{Objfiles In Python}, for more details on objfiles in Python.
+@end itemize
+
+@xref{Selecting Pretty-Printers}, for further information on how
+pretty-printers are selected,
+
+@xref{Writing a Pretty-Printer}, for implementing pretty printers
+for new types.
+
+@node Pretty-Printer Example
+@subsection Pretty-Printer Example
+
+Here is how a C@t{++} @code{std::string} looks without a pretty-printer:
+
+@smallexample
+(@value{GDBP}) print s
+$1 = @{
+ static npos = 4294967295,
+ _M_dataplus = @{
+ <std::allocator<char>> = @{
+ <__gnu_cxx::new_allocator<char>> = @{
+ <No data fields>@}, <No data fields>
+ @},
+ members of std::basic_string<char, std::char_traits<char>,
+ std::allocator<char> >::_Alloc_hider:
+ _M_p = 0x804a014 "abcd"
+ @}
+@}
+@end smallexample
+
+With a pretty-printer for @code{std::string} only the contents are printed:
+
+@smallexample
+(@value{GDBP}) print s
+$2 = "abcd"
+@end smallexample
+
+@node Pretty-Printer Commands
+@subsection Pretty-Printer Commands
+@cindex pretty-printer commands
+
+@table @code
+@kindex info pretty-printer
+@item info pretty-printer [@var{object-regexp} [@var{name-regexp}]]
+Print the list of installed pretty-printers.
+This includes disabled pretty-printers, which are marked as such.
+
+@var{object-regexp} is a regular expression matching the objects
+whose pretty-printers to list.
+Objects can be @code{global}, the program space's file
+(@pxref{Progspaces In Python}),
+and the object files within that program space (@pxref{Objfiles In Python}).
+@xref{Selecting Pretty-Printers}, for details on how @value{GDBN}
+looks up a printer from these three objects.
+
+@var{name-regexp} is a regular expression matching the name of the printers
+to list.
+
+@kindex disable pretty-printer
+@item disable pretty-printer [@var{object-regexp} [@var{name-regexp}]]
+Disable pretty-printers matching @var{object-regexp} and @var{name-regexp}.
+A disabled pretty-printer is not forgotten, it may be enabled again later.
+
+@kindex enable pretty-printer
+@item enable pretty-printer [@var{object-regexp} [@var{name-regexp}]]
+Enable pretty-printers matching @var{object-regexp} and @var{name-regexp}.
+@end table
+
+Example:
+
+Suppose we have three pretty-printers installed: one from library1.so
+named @code{foo} that prints objects of type @code{foo}, and
+another from library2.so named @code{bar} that prints two types of objects,
+@code{bar1} and @code{bar2}.
+
+@smallexample
+(gdb) info pretty-printer
+library1.so:
+ foo
+library2.so:
+ bar
+ bar1
+ bar2
+(gdb) info pretty-printer library2
+library2.so:
+ bar
+ bar1
+ bar2
+(gdb) disable pretty-printer library1
+1 printer disabled
+2 of 3 printers enabled
+(gdb) info pretty-printer
+library1.so:
+ foo [disabled]
+library2.so:
+ bar
+ bar1
+ bar2
+(gdb) disable pretty-printer library2 bar:bar1
+1 printer disabled
+1 of 3 printers enabled
+(gdb) info pretty-printer library2
+library1.so:
+ foo [disabled]
+library2.so:
+ bar
+ bar1 [disabled]
+ bar2
+(gdb) disable pretty-printer library2 bar
+1 printer disabled
+0 of 3 printers enabled
+(gdb) info pretty-printer library2
+library1.so:
+ foo [disabled]
+library2.so:
+ bar [disabled]
+ bar1 [disabled]
+ bar2
+@end smallexample
+
+Note that for @code{bar} the entire printer can be disabled,
+as can each individual subprinter.
+
@node Value History
@section Value History
The variable @code{$_exitcode} is automatically set to the exit code when
the program being debugged terminates.
+@item $_sdata
+@vindex $_sdata@r{, inspect, convenience variable}
+The variable @code{$_sdata} contains extra collected static tracepoint
+data. @xref{Tracepoint Actions,,Tracepoint Action Lists}. Note that
+@code{$_sdata} could be empty, if not inspecting a trace buffer, or
+if extra static tracepoint data has not been collected.
+
@item $_siginfo
@vindex $_siginfo@r{, convenience variable}
The variable @code{$_siginfo} contains extra signal information
(@pxref{extra signal information}). Note that @code{$_siginfo}
could be empty, if the application has not yet received any signals.
For example, it will be empty before you execute the @code{run} command.
+
+@item $_tlb
+@vindex $_tlb@r{, convenience variable}
+The variable @code{$_tlb} is automatically set when debugging
+applications running on MS-Windows in native mode or connected to
+gdbserver that supports the @code{qGetTIBAddr} request.
+@xref{General Query Packets}.
+This variable contains the address of the thread information block.
+
@end table
On HP-UX systems, if you refer to a function or variable name that
@samp{qXfer:osdata:read} packet, see @ref{qXfer osdata read}.
@table @code
+@kindex info os
+@item info os
+List the types of OS information available for the target. If the
+target does not return a list of possible types, this command will
+report an error.
+
@kindex info os processes
@item info os processes
Display the list of processes on the target. For each process,
case, @value{GDBN} uses @samp{UTF-8}.
@value{GDBN} can only use certain character sets as its host character
-set. If you type @kbd{@w{set target-charset @key{TAB}@key{TAB}}},
+set. If you type @kbd{@w{set host-charset @key{TAB}@key{TAB}}},
@value{GDBN} will list the host character sets it supports.
@item set charset @var{charset}
a different way (such as with a jump instead of a trap), that is
faster but possibly restricted in where they may be installed.
+@cindex static tracepoints
+@cindex markers, static tracepoints
+@cindex probing markers, static tracepoints
+Regular and fast tracepoints are dynamic tracing facilities, meaning
+that they can be used to insert tracepoints at (almost) any location
+in the target. Some targets may also support controlling @dfn{static
+tracepoints} from @value{GDBN}. With static tracing, a set of
+instrumentation points, also known as @dfn{markers}, are embedded in
+the target program, and can be activated or deactivated by name or
+address. These are usually placed at locations which facilitate
+investigating what the target is actually doing. @value{GDBN}'s
+support for static tracing includes being able to list instrumentation
+points, and attach them with @value{GDBN} defined high level
+tracepoints that expose the whole range of convenience of
+@value{GDBN}'s tracepoints support. Namelly, support for collecting
+registers values and values of global or local (to the instrumentation
+point) variables; tracepoint conditions and trace state variables.
+The act of installing a @value{GDBN} static tracepoint on an
+instrumentation point, or marker, is referred to as @dfn{probing} a
+static tracepoint marker.
+
+@code{gdbserver} supports tracepoints on some target systems.
+@xref{Server,,Tracepoints support in @code{gdbserver}}.
+
This section describes commands to set tracepoints and associated
conditions and actions.
* Trace State Variables::
* Tracepoint Actions::
* Listing Tracepoints::
+* Listing Static Tracepoint Markers::
* Starting and Stopping Trace Experiments::
* Tracepoint Restrictions::
@end menu
@item ftrace @var{location} [ if @var{cond} ]
@cindex set fast tracepoint
+@cindex fast tracepoints, setting
@kindex ftrace
The @code{ftrace} command sets a fast tracepoint. For targets that
support them, fast tracepoints will use a more efficient but possibly
@value{GDBN} handles arguments to @code{ftrace} exactly as for
@code{trace}.
+@item strace @var{location} [ if @var{cond} ]
+@cindex set static tracepoint
+@cindex static tracepoints, setting
+@cindex probe static tracepoint marker
+@kindex strace
+The @code{strace} command sets a static tracepoint. For targets that
+support it, setting a static tracepoint probes a static
+instrumentation point, or marker, found at @var{location}. It may not
+be possible to set a static tracepoint at the desired location, in
+which case the command will exit with an explanatory message.
+
+@value{GDBN} handles arguments to @code{strace} exactly as for
+@code{trace}, with the addition that the user can also specify
+@code{-m @var{marker}} as @var{location}. This probes the marker
+identified by the @var{marker} string identifier. This identifier
+depends on the static tracepoint backend library your program is
+using. You can find all the marker identifiers in the @samp{ID} field
+of the @code{info static-tracepoint-markers} command output.
+@xref{Listing Static Tracepoint Markers,,Listing Static Tracepoint
+Markers}. For example, in the following small program using the UST
+tracing engine:
+
+@smallexample
+main ()
+@{
+ trace_mark(ust, bar33, "str %s", "FOOBAZ");
+@}
+@end smallexample
+
+@noindent
+the marker id is composed of joining the first two arguments to the
+@code{trace_mark} call with a slash, which translates to:
+
+@smallexample
+(@value{GDBP}) info static-tracepoint-markers
+Cnt Enb ID Address What
+1 n ust/bar33 0x0000000000400ddc in main at stexample.c:22
+ Data: "str %s"
+[etc...]
+@end smallexample
+
+@noindent
+so you may probe the marker above with:
+
+@smallexample
+(@value{GDBP}) strace -m ust/bar33
+@end smallexample
+
+Static tracepoints accept an extra collect action --- @code{collect
+$_sdata}. This collects arbitrary user data passed in the probe point
+call to the tracing library. In the UST example above, you'll see
+that the third argument to @code{trace_mark} is a printf-like format
+string. The user data is then the result of running that formating
+string against the following arguments. Note that @code{info
+static-tracepoint-markers} command output lists that format string in
+the @samp{Data:} field.
+
+You can inspect this data when analyzing the trace buffer, by printing
+the $_sdata variable like any other variable available to
+@value{GDBN}. @xref{Tracepoint Actions,,Tracepoint Action Lists}.
+
@vindex $tpnum
@cindex last tracepoint number
@cindex recent tracepoint number
far, the only defined actions are @code{collect}, @code{teval}, and
@code{while-stepping}.
+@code{actions} is actually equivalent to @code{commands} (@pxref{Break
+Commands, ,Breakpoint Command Lists}), except that only the defined
+actions are allowed; any other @value{GDBN} command is rejected.
+
@cindex remove actions from a tracepoint
To remove all actions from a tracepoint, type @samp{actions @var{num}}
and follow it immediately with @samp{end}.
> collect bar,baz
> collect $regs
> while-stepping 12
- > collect $fp, $sp
+ > collect $pc, arr[i]
> end
end
@end smallexample
@table @code
@item $regs
-collect all registers
+Collect all registers.
@item $args
-collect all function arguments
+Collect all function arguments.
@item $locals
-collect all local variables.
+Collect all local variables.
+
+@item $_sdata
+@vindex $_sdata@r{, collect}
+Collect static tracepoint marker specific data. Only available for
+static tracepoints. @xref{Tracepoint Actions,,Tracepoint Action
+Lists}. On the UST static tracepoints library backend, an
+instrumentation point resembles a @code{printf} function call. The
+tracing library is able to collect user specified data formatted to a
+character string using the format provided by the programmer that
+instrumented the program. Other backends have similar mechanisms.
+Here's an example of a UST marker call:
+
+@smallexample
+ const char master_name[] = "$your_name";
+ trace_mark(channel1, marker1, "hello %s", master_name)
+@end smallexample
+
+In this case, collecting @code{$_sdata} collects the string
+@samp{hello $yourname}. When analyzing the trace buffer, you can
+inspect @samp{$_sdata} like any other variable available to
+@value{GDBN}.
@end table
You can give several consecutive @code{collect} commands, each one
with a single argument, or one @code{collect} command with several
-arguments separated by commas: the effect is the same.
+arguments separated by commas; the effect is the same.
The command @code{info scope} (@pxref{Symbols, info scope}) is
particularly useful for figuring out what data to collect.
@itemize @bullet
@item
its passcount as given by the @code{passcount @var{n}} command
-@item
-its step count as given by the @code{while-stepping @var{n}} command
-@item
-its action list as given by the @code{actions} command. The actions
-are prefixed with an @samp{A} so as to distinguish them from commands.
@end itemize
@smallexample
(@value{GDBP}) @b{info trace}
Num Type Disp Enb Address What
1 tracepoint keep y 0x0804ab57 in foo() at main.cxx:7
+ while-stepping 20
+ collect globfoo, $regs
+ end
+ collect globfoo2
+ end
pass count 1200
- step count 20
- A while-stepping 20
- A collect globfoo, $regs
- A end
- A collect globfoo2
- A end
(@value{GDBP})
@end smallexample
This command can be abbreviated @code{info tp}.
@end table
+@node Listing Static Tracepoint Markers
+@subsection Listing Static Tracepoint Markers
+
+@table @code
+@kindex info static-tracepoint-markers
+@cindex information about static tracepoint markers
+@item info static-tracepoint-markers
+Display information about all static tracepoint markers defined in the
+program.
+
+For each marker, the following columns are printed:
+
+@table @emph
+@item Count
+An incrementing counter, output to help readability. This is not a
+stable identifier.
+@item ID
+The marker ID, as reported by the target.
+@item Enabled or Disabled
+Probed markers are tagged with @samp{y}. @samp{n} identifies marks
+that are not enabled.
+@item Address
+Where the marker is in your program, as a memory address.
+@item What
+Where the marker is in the source for your program, as a file and line
+number. If the debug information included in the program does not
+allow @value{GDBN} to locate the source of the marker, this column
+will be left blank.
+@end table
+
+@noindent
+In addition, the following information may be printed for each marker:
+
+@table @emph
+@item Data
+User data passed to the tracing library by the marker call. In the
+UST backend, this is the format string passed as argument to the
+marker call.
+@item Static tracepoints probing the marker
+The list of static tracepoints attached to the marker.
+@end table
+
+@smallexample
+(@value{GDBP}) info static-tracepoint-markers
+Cnt ID Enb Address What
+1 ust/bar2 y 0x0000000000400e1a in main at stexample.c:25
+ Data: number1 %d number2 %d
+ Probed by static tracepoints: #2
+2 ust/bar33 n 0x0000000000400c87 in main at stexample.c:24
+ Data: str %s
+(@value{GDBP})
+@end smallexample
+@end table
+
@node Starting and Stopping Trace Experiments
@subsection Starting and Stopping Trace Experiments
@menu
* tfind:: How to select a trace snapshot
* tdump:: How to display all data for a snapshot
-* save-tracepoints:: How to save tracepoints for a future run
+* save tracepoints:: How to save tracepoints for a future run
@end menu
@node tfind
same data that is collected at the tracepoint hit.
@c This is getting pretty arcane, example would be good.
-@node save-tracepoints
-@subsection @code{save-tracepoints @var{filename}}
+@node save tracepoints
+@subsection @code{save tracepoints @var{filename}}
+@kindex save tracepoints
@kindex save-tracepoints
@cindex save tracepoints for future sessions
their actions and passcounts, into a file @file{@var{filename}}
suitable for use in a later debugging session. To read the saved
tracepoint definitions, use the @code{source} command (@pxref{Command
-Files}).
+Files}). The @w{@code{save-tracepoints}} command is a deprecated
+alias for @w{@code{save tracepoints}}
@node Tracepoint Variables
@section Convenience Variables for Tracepoints
@itemx .c++
C@t{++} source file
+@item .d
+D source file
+
@item .m
Objective-C source file
@node Supported Languages
@section Supported Languages
-@value{GDBN} supports C, C@t{++}, Objective-C, Fortran, Java, Pascal,
+@value{GDBN} supports C, C@t{++}, D, Objective-C, Fortran, Java, OpenCL C, Pascal,
assembly, Modula-2, and Ada.
@c This is false ...
Some @value{GDBN} features may be used in expressions regardless of the
@menu
* C:: C and C@t{++}
+* D:: D
* Objective-C:: Objective-C
+* OpenCL C:: OpenCL C
* Fortran:: Fortran
* Pascal:: Pascal
* Modula-2:: Modula-2
to inspect @code{_Decimal128} values stored in floating point registers.
See @ref{PowerPC,,PowerPC} for more details.
+@node D
+@subsection D
+
+@cindex D
+@value{GDBN} can be used to debug programs written in D and compiled with
+GDC, LDC or DMD compilers. Currently @value{GDBN} supports only one D
+specific feature --- dynamic arrays.
+
@node Objective-C
@subsection Objective-C
with certain Objective-C libraries that have a particular hook
function, @code{_NSPrintForDebugger}, defined.
+@node OpenCL C
+@subsection OpenCL C
+
+@cindex OpenCL C
+This section provides information about @value{GDBN}s OpenCL C support.
+
+@menu
+* OpenCL C Datatypes::
+* OpenCL C Expressions::
+* OpenCL C Operators::
+@end menu
+
+@node OpenCL C Datatypes
+@subsubsection OpenCL C Datatypes
+
+@cindex OpenCL C Datatypes
+@value{GDBN} supports the builtin scalar and vector datatypes specified
+by OpenCL 1.1. In addition the half- and double-precision floating point
+data types of the @code{cl_khr_fp16} and @code{cl_khr_fp64} OpenCL
+extensions are also known to @value{GDBN}.
+
+@node OpenCL C Expressions
+@subsubsection OpenCL C Expressions
+
+@cindex OpenCL C Expressions
+@value{GDBN} supports accesses to vector components including the access as
+lvalue where possible. Since OpenCL C is based on C99 most C expressions
+supported by @value{GDBN} can be used as well.
+
+@node OpenCL C Operators
+@subsubsection OpenCL C Operators
+
+@cindex OpenCL C Operators
+@value{GDBN} supports the operators specified by OpenCL 1.1 for scalar and
+vector data types.
+
@node Fortran
@subsection Fortran
@cindex Fortran-specific support in @value{GDBN}
* Stopping Before Main Program:: Debugging the program during elaboration.
* Ada Tasks:: Listing and setting breakpoints in tasks.
* Ada Tasks and Core Files:: Tasking Support when Debugging Core Files
+* Ravenscar Profile:: Tasking Support when using the Ravenscar
+ Profile
* Ada Glitches:: Known peculiarities of Ada mode.
@end menu
Under these circumstances, you should make a backup copy of the core
file before inspecting it with @value{GDBN}.
+@node Ravenscar Profile
+@subsubsection Tasking Support when using the Ravenscar Profile
+@cindex Ravenscar Profile
+
+The @dfn{Ravenscar Profile} is a subset of the Ada tasking features,
+specifically designed for systems with safety-critical real-time
+requirements.
+
+@table @code
+@kindex set ravenscar task-switching on
+@cindex task switching with program using Ravenscar Profile
+@item set ravenscar task-switching on
+Allows task switching when debugging a program that uses the Ravenscar
+Profile. This is the default.
+
+@kindex set ravenscar task-switching off
+@item set ravenscar task-switching off
+Turn off task switching when debugging a program that uses the Ravenscar
+Profile. This is mostly intended to disable the code that adds support
+for the Ravenscar Profile, in case a bug in either @value{GDBN} or in
+the Ravenscar runtime is preventing @value{GDBN} from working properly.
+To be effective, this command should be run before the program is started.
+
+@kindex show ravenscar task-switching
+@item show ravenscar task-switching
+Show whether it is possible to switch from task to task in a program
+using the Ravenscar Profile.
+
+@end table
+
@node Ada Glitches
@subsubsection Known Peculiarities of Ada Mode
@cindex Ada, problems
and the GNU Ada compiler.
@itemize @bullet
-@item
-Currently, the debugger
-has insufficient information to determine whether certain pointers represent
-pointers to objects or the objects themselves.
-Thus, the user may have to tack an extra @code{.all} after an expression
-to get it printed properly.
-
@item
Static constants that the compiler chooses not to materialize as objects in
storage are invisible to the debugger.
@menu
* Files:: Commands to specify files
* Separate Debug Files:: Debugging information in separate files
+* Index Files:: Index files speed up GDB
* Symbol Errors:: Errors reading symbol files
* Data Files:: GDB data files
@end menu
that happens to be named @file{remote:}, you need to use some equivalent
variant of the name like @file{./remote:}.}
+For targets with an MS-DOS based filesystem, such as MS-Windows and
+SymbianOS, @value{GDBN} tries prefixing a few variants of the target
+absolute file name with @var{path}. But first, on Unix hosts,
+@value{GDBN} converts all backslash directory separators into forward
+slashes, because the backslash is not a directory separator on Unix:
+
+@smallexample
+ c:\foo\bar.dll @result{} c:/foo/bar.dll
+@end smallexample
+
+Then, @value{GDBN} attempts prefixing the target file name with
+@var{path}, and looks for the resulting file name in the host file
+system:
+
+@smallexample
+ c:/foo/bar.dll @result{} /path/to/sysroot/c:/foo/bar.dll
+@end smallexample
+
+If that does not find the shared library, @value{GDBN} tries removing
+the @samp{:} character from the drive spec, both for convenience, and,
+for the case of the host file system not supporting file names with
+colons:
+
+@smallexample
+ c:/foo/bar.dll @result{} /path/to/sysroot/c/foo/bar.dll
+@end smallexample
+
+This makes it possible to have a system root that mirrors a target
+with more than one drive. E.g., you may want to setup your local
+copies of the target system shared libraries like so (note @samp{c} vs
+@samp{z}):
+
+@smallexample
+ @file{/path/to/sysroot/c/sys/bin/foo.dll}
+ @file{/path/to/sysroot/c/sys/bin/bar.dll}
+ @file{/path/to/sysroot/z/sys/bin/bar.dll}
+@end smallexample
+
+@noindent
+and point the system root at @file{/path/to/sysroot}, so that
+@value{GDBN} can find the correct copies of both
+@file{c:\sys\bin\foo.dll}, and @file{z:\sys\bin\bar.dll}.
+
+If that still does not find the shared library, @value{GDBN} tries
+removing the whole drive spec from the target file name:
+
+@smallexample
+ c:/foo/bar.dll @result{} /path/to/sysroot/foo/bar.dll
+@end smallexample
+
+This last lookup makes it possible to not care about the drive name,
+if you don't want or need to.
+
The @code{set solib-absolute-prefix} command is an alias for @code{set
sysroot}.
@kindex show solib-search-path
@item show solib-search-path
Display the current shared library search path.
+
+@cindex DOS file-name semantics of file names.
+@kindex set target-file-system-kind (unix|dos-based|auto)
+@kindex show target-file-system-kind
+@item set target-file-system-kind @var{kind}
+Set assumed file system kind for target reported file names.
+
+Shared library file names as reported by the target system may not
+make sense as is on the system @value{GDBN} is running on. For
+example, when remote debugging a target that has MS-DOS based file
+system semantics, from a Unix host, the target may be reporting to
+@value{GDBN} a list of loaded shared libraries with file names such as
+@file{c:\Windows\kernel32.dll}. On Unix hosts, there's no concept of
+drive letters, so the @samp{c:\} prefix is not normally understood as
+indicating an absolute file name, and neither is the backslash
+normally considered a directory separator character. In that case,
+the native file system would interpret this whole absolute file name
+as a relative file name with no directory components. This would make
+it impossible to point @value{GDBN} at a copy of the remote target's
+shared libraries on the host using @code{set sysroot}, and impractical
+with @code{set solib-search-path}. Setting
+@code{target-file-system-kind} to @code{dos-based} tells @value{GDBN}
+to interpret such file names similarly to how the target would, and to
+map them to file names valid on @value{GDBN}'s native file system
+semantics. The value of @var{kind} can be @code{"auto"}, in addition
+to one of the supported file system kinds. In that case, @value{GDBN}
+tries to determine the appropriate file system variant based on the
+current target's operating system (@pxref{ABI, ,Configuring the
+Current ABI}). The supported file system settings are:
+
+@table @code
+@item unix
+Instruct @value{GDBN} to assume the target file system is of Unix
+kind. Only file names starting the forward slash (@samp{/}) character
+are considered absolute, and the directory separator character is also
+the forward slash.
+
+@item dos-based
+Instruct @value{GDBN} to assume the target file system is DOS based.
+File names starting with either a forward slash, or a drive letter
+followed by a colon (e.g., @samp{c:}), are considered absolute, and
+both the slash (@samp{/}) and the backslash (@samp{\\}) characters are
+considered directory separators.
+
+@item auto
+Instruct @value{GDBN} to use the file system kind associated with the
+target operating system (@pxref{ABI, ,Configuring the Current ABI}).
+This is the default.
+@end table
@end table
This computation does not apply to the ``build ID'' method.
+@node Index Files
+@section Index Files Speed Up @value{GDBN}
+@cindex index files
+@cindex @samp{.gdb_index} section
+
+When @value{GDBN} finds a symbol file, it scans the symbols in the
+file in order to construct an internal symbol table. This lets most
+@value{GDBN} operations work quickly---at the cost of a delay early
+on. For large programs, this delay can be quite lengthy, so
+@value{GDBN} provides a way to build an index, which speeds up
+startup.
+
+The index is stored as a section in the symbol file. @value{GDBN} can
+write the index to a file, then you can put it into the symbol file
+using @command{objcopy}.
+
+To create an index file, use the @code{save gdb-index} command:
+
+@table @code
+@item save gdb-index @var{directory}
+@kindex save gdb-index
+Create an index file for each symbol file currently known by
+@value{GDBN}. Each file is named after its corresponding symbol file,
+with @samp{.gdb-index} appended, and is written into the given
+@var{directory}.
+@end table
+
+Once you have created an index file you can merge it into your symbol
+file, here named @file{symfile}, using @command{objcopy}:
+
+@smallexample
+$ objcopy --add-section .gdb_index=symfile.gdb-index \
+ --set-section-flags .gdb_index=readonly symfile symfile
+@end smallexample
+
+There are currently some limitation on indices. They only work when
+for DWARF debugging information, not stabs. And, they do not
+currently work for programs using Ada.
+
@node Symbol Errors
@section Errors Reading Symbol Files
automatically if the installed @value{GDBN} is moved to a new
location.
+The data directory may also be specified with the
+@code{--data-directory} command line option.
+@xref{Mode Options}.
+
@node Targets
@chapter Specifying a Debugging Target
@cindex active targets
@cindex multiple targets
-There are three classes of targets: processes, core files, and
-executable files. @value{GDBN} can work concurrently on up to three
-active targets, one in each class. This allows you to (for example)
-start a process and inspect its activity without abandoning your work on
-a core file.
-
-For example, if you execute @samp{gdb a.out}, then the executable file
-@code{a.out} is the only active target. If you designate a core file as
-well---presumably from a prior run that crashed and coredumped---then
-@value{GDBN} has two active targets and uses them in tandem, looking
-first in the corefile target, then in the executable file, to satisfy
-requests for memory addresses. (Typically, these two classes of target
-are complementary, since core files contain only a program's
-read-write memory---variables and so on---plus machine status, while
-executable files contain only the program text and initialized data.)
-
-When you type @code{run}, your executable file becomes an active process
-target as well. When a process target is active, all @value{GDBN}
-commands requesting memory addresses refer to that target; addresses in
-an active core file or executable file target are obscured while the
-process target is active.
-
-Use the @code{core-file} and @code{exec-file} commands to select a new
-core file or executable target (@pxref{Files, ,Commands to Specify
-Files}). To specify as a target a process that is already running, use
-the @code{attach} command (@pxref{Attach, ,Debugging an Already-running
-Process}).
+There are multiple classes of targets such as: processes, executable files or
+recording sessions. Core files belong to the process class, making core file
+and process mutually exclusive. Otherwise, @value{GDBN} can work concurrently
+on multiple active targets, one in each class. This allows you to (for
+example) start a process and inspect its activity, while still having access to
+the executable file after the process finishes. Or if you start process
+recording (@pxref{Reverse Execution}) and @code{reverse-step} there, you are
+presented a virtual layer of the recording target, while the process target
+remains stopped at the chronologically last point of the process execution.
+
+Use the @code{core-file} and @code{exec-file} commands to select a new core
+file or executable target (@pxref{Files, ,Commands to Specify Files}). To
+specify as a target a process that is already running, use the @code{attach}
+command (@pxref{Attach, ,Debugging an Already-running Process}).
@node Target Commands
@section Commands for Managing Targets
@end table
+@subsection Tracepoints support in @code{gdbserver}
+@cindex tracepoints support in @code{gdbserver}
+
+On some targets, @code{gdbserver} supports tracepoints, fast
+tracepoints and static tracepoints.
+
+For fast or static tracepoints to work, a special library called the
+@dfn{in-process agent} (IPA), must be loaded in the inferior process.
+This library is built and distributed as an integral part of
+@code{gdbserver}. In addition, support for static tracepoints
+requires building the in-process agent library with static tracepoints
+support. At present, the UST (LTTng Userspace Tracer,
+@url{http://lttng.org/ust}) tracing engine is supported. This support
+is automatically available if UST development headers are found in the
+standard include path when @code{gdbserver} is built, or if
+@code{gdbserver} was explicitly configured using @option{--with-ust}
+to point at such headers. You can explicitly disable the support
+using @option{--with-ust=no}.
+
+There are several ways to load the in-process agent in your program:
+
+@table @code
+@item Specifying it as dependency at link time
+
+You can link your program dynamically with the in-process agent
+library. On most systems, this is accomplished by adding
+@code{-linproctrace} to the link command.
+
+@item Using the system's preloading mechanisms
+
+You can force loading the in-process agent at startup time by using
+your system's support for preloading shared libraries. Many Unixes
+support the concept of preloading user defined libraries. In most
+cases, you do that by specifying @code{LD_PRELOAD=libinproctrace.so}
+in the environment. See also the description of @code{gdbserver}'s
+@option{--wrapper} command line option.
+
+@item Using @value{GDBN} to force loading the agent at run time
+
+On some systems, you can force the inferior to load a shared library,
+by calling a dynamic loader function in the inferior that takes care
+of dynamically looking up and loading a shared library. On most Unix
+systems, the function is @code{dlopen}. You'll use the @code{call}
+command for that. For example:
+
+@smallexample
+(@value{GDBP}) call dlopen ("libinproctrace.so", ...)
+@end smallexample
+
+Note that on most Unix systems, for the @code{dlopen} function to be
+available, the program needs to be linked with @code{-ldl}.
+@end table
+
+On systems that have a userspace dynamic loader, like most Unix
+systems, when you connect to @code{gdbserver} using @code{target
+remote}, you'll find that the program is stopped at the dynamic
+loader's entry point, and no shared library has been loaded in the
+program's address space yet, including the in-process agent. In that
+case, before being able to use any of the fast or static tracepoints
+features, you need to let the loader run and load the shared
+libraries. The simplest way to do that is to run the program to the
+main procedure. E.g., if debugging a C or C@t{++} program, start
+@code{gdbserver} like so:
+
+@smallexample
+$ gdbserver :9999 myprogram
+@end smallexample
+
+Start GDB and connect to @code{gdbserver} like so, and run to main:
+
+@smallexample
+$ gdb myprogram
+(@value{GDBP}) target remote myhost:9999
+0x00007f215893ba60 in ?? () from /lib64/ld-linux-x86-64.so.2
+(@value{GDBP}) b main
+(@value{GDBP}) continue
+@end smallexample
+
+The in-process tracing agent library should now be loaded into the
+process; you can confirm it with the @code{info sharedlibrary}
+command, which will list @file{libinproctrace.so} as loaded in the
+process. You are now ready to install fast tracepoints, list static
+tracepoint markers, probe static tracepoints markers, and start
+tracing.
+
@node Remote Configuration
@section Remote Configuration
@tab @code{qXfer:memory-map:read}
@tab @code{info mem}
+@item @code{read-sdata-object}
+@tab @code{qXfer:sdata:read}
+@tab @code{print $_sdata}
+
@item @code{read-spu-object}
@tab @code{qXfer:spu:read}
@tab @code{info spu}
@tab @code{qGetTLSAddr}
@tab Displaying @code{__thread} variables
+@item @code{get-thread-information-block-address}
+@tab @code{qGetTIBAddr}
+@tab Display MS-Windows Thread Information Block.
+
@item @code{search-memory}
@tab @code{qSearch:memory}
@tab @code{find}
Without argument, this command displays information
about the six segment registers.
+@item info w32 thread-information-block
+This command displays thread specific information stored in the
+Thread Information Block (readable on the X86 CPU family using @code{$fs}
+selector for 32-bit programs and @code{$gs} for 64-bit programs).
+
@kindex info dll
@item info dll
This is a Cygwin-specific alias of @code{info shared}.
@node PowerPC Embedded
@subsection PowerPC Embedded
+@cindex DVC register
+@value{GDBN} supports using the DVC (Data Value Compare) register to
+implement in hardware simple hardware watchpoint conditions of the form:
+
+@smallexample
+(@value{GDBP}) watch @var{ADDRESS|VARIABLE} \
+ if @var{ADDRESS|VARIABLE} == @var{CONSTANT EXPRESSION}
+@end smallexample
+
+The DVC register will be automatically used when @value{GDBN} detects
+such pattern in a condition expression, and the created watchpoint uses one
+debug register (either the @code{exact-watchpoints} option is on and the
+variable is scalar, or the variable has a length of one byte). This feature
+is available in native @value{GDBN} running on a Linux kernel version 2.6.34
+or newer.
+
+When running on PowerPC embedded processors, @value{GDBN} automatically uses
+ranged hardware watchpoints, unless the @code{exact-watchpoints} option is on,
+in which case watchpoints using only one debug register are created when
+watching variables of scalar types.
+
+You can create an artificial array to watch an arbitrary memory
+region using one of the following commands (@pxref{Expressions}):
+
+@smallexample
+(@value{GDBP}) watch *((char *) @var{address})@@@var{length}
+(@value{GDBP}) watch @{char[@var{length}]@} @var{address}
+@end smallexample
+
@value{GDBN} provides the following PowerPC-specific commands:
@table @code
registers. By default, @value{GDBN} selects the calling convention
based on the selected architecture and the provided executable file.
+@item set powerpc exact-watchpoints
+@itemx show powerpc exact-watchpoints
+Allow @value{GDBN} to use only one debug register when watching a variable
+of scalar type, thus assuming that the variable is accessed through the
+address of its first byte.
+
@kindex target dink32
@item target dink32 @var{dev}
DINK32 ROM monitor.
Show whether command line editing is enabled.
@end table
-@xref{Command Line Editing}, for more details about the Readline
+@ifset SYSTEM_READLINE
+@xref{Command Line Editing, , , rluserman, GNU Readline Library},
+@end ifset
+@ifclear SYSTEM_READLINE
+@xref{Command Line Editing},
+@end ifclear
+for more details about the Readline
interface. Users unfamiliar with @sc{gnu} Emacs or @code{vi} are
encouraged to read that chapter.
history facility.
@value{GDBN} uses the @sc{gnu} History library, a part of the Readline
-package, to provide the history facility. @xref{Using History
-Interactively}, for the detailed description of the History library.
+package, to provide the history facility.
+@ifset SYSTEM_READLINE
+@xref{Using History Interactively, , , history, GNU History Library},
+@end ifset
+@ifclear SYSTEM_READLINE
+@xref{Using History Interactively},
+@end ifclear
+for the detailed description of the History library.
To issue a command to @value{GDBN} without affecting certain aspects of
the state which is seen by users, prefix it with @samp{server }
@end table
History expansion assigns special meaning to the character @kbd{!}.
-@xref{Event Designators}, for more details.
+@ifset SYSTEM_READLINE
+@xref{Event Designators, , , history, GNU History Library},
+@end ifset
+@ifclear SYSTEM_READLINE
+@xref{Event Designators},
+@end ifclear
+for more details.
@cindex history expansion, turn on/off
Since @kbd{!} is also the logical not operator in C, history expansion
for implementing operations such as single-stepping the inferior.
@item show debug infrun
Displays the current state of @value{GDBN} inferior debugging.
+@item set debug jit
+@cindex just-in-time compilation, debugging messages
+Turns on or off debugging messages from JIT debug support.
+@item show debug jit
+Displays the current state of @value{GDBN} JIT debugging.
@item set debug lin-lwp
@cindex @sc{gnu}/Linux LWP debug messages
@cindex Linux lightweight processes
@table @code
@kindex source
@cindex execute commands from a file
-@item source [@code{-v}] @var{filename}
+@item source [-s] [-v] @var{filename}
Execute the command file @var{filename}.
@end table
printed as they are executed. An error in any command terminates
execution of the command file and control is returned to the console.
-@value{GDBN} searches for @var{filename} in the current directory and then
-on the search path (specified with the @samp{directory} command).
+@value{GDBN} first searches for @var{filename} in the current directory.
+If the file is not found there, and @var{filename} does not specify a
+directory, then @value{GDBN} also looks for the file on the source search path
+(specified with the @samp{directory} command);
+except that @file{$cdir} is not searched because the compilation directory
+is not relevant to scripts.
+
+If @code{-s} is specified, then @value{GDBN} searches for @var{filename}
+on the search path even if @var{filename} specifies a directory.
+The search is done by appending @var{filename} to each element of the
+search path. So, for example, if @var{filename} is @file{mylib/myscript}
+and the search path contains @file{/home/user} then @value{GDBN} will
+look for the script @file{/home/user/mylib/myscript}.
+The search is also done if @var{filename} is an absolute path.
+For example, if @var{filename} is @file{/tmp/myscript} and
+the search path contains @file{/home/user} then @value{GDBN} will
+look for the script @file{/home/user/tmp/myscript}.
+For DOS-like systems, if @var{filename} contains a drive specification,
+it is stripped before concatenation. For example, if @var{filename} is
+@file{d:myscript} and the search path contains @file{c:/tmp} then @value{GDBN}
+will look for the script @file{c:/tmp/myscript}.
If @code{-v}, for verbose mode, is given then @value{GDBN} displays
each command as it is executed. The option must be given before
printf "D32: %Hf - D64: %Df - D128: %DDf\n",1.2345df,1.2E10dd,1.2E1dl
@end smallexample
+@kindex eval
+@item eval @var{template}, @var{expressions}@dots{}
+Convert the values of one or more @var{expressions} under the control of
+the string @var{template} to a command line, and call it.
+
@end table
@node Python
Python programming language}. This feature is available only if
@value{GDBN} was configured using @option{--with-python}.
+@cindex python directory
+Python scripts used by @value{GDBN} should be installed in
+@file{@var{data-directory}/python}, where @var{data-directory} is
+the data directory as determined at @value{GDBN} startup (@pxref{Data Files}).
+This directory, known as the @dfn{python directory},
+is automatically added to the Python Search Path in order to allow
+the Python interpreter to locate all scripts installed at this location.
+
@menu
* Python Commands:: Accessing Python from @value{GDBN}.
* Python API:: Accessing @value{GDBN} from Python.
+* Auto-loading:: Automatically loading Python code.
+* Python modules:: Python modules provided by @value{GDBN}.
@end menu
@node Python Commands
@menu
* Basic Python:: Basic Python Functions.
-* Exception Handling::
-* Auto-loading:: Automatically loading Python code.
-* Values From Inferior::
-* Types In Python:: Python representation of types.
-* Pretty Printing:: Pretty-printing values.
+* Exception Handling:: How Python exceptions are translated.
+* Values From Inferior:: Python representation of values.
+* Types In Python:: Python representation of types.
+* Pretty Printing API:: Pretty-printing values.
* Selecting Pretty-Printers:: How GDB chooses a pretty-printer.
+* Writing a Pretty-Printer:: Writing a Pretty-Printer.
+* Inferiors In Python:: Python representation of inferiors (processes)
+* Threads In Python:: Accessing inferior threads from Python.
* Commands In Python:: Implementing new commands in Python.
+* Parameters In Python:: Adding new @value{GDBN} parameters.
* Functions In Python:: Writing new convenience functions.
+* Progspaces In Python:: Program spaces.
* Objfiles In Python:: Object files.
* Frames In Python:: Accessing inferior stack frames from Python.
* Blocks In Python:: Accessing frame blocks from Python.
* Symbols In Python:: Python representation of symbols.
* Symbol Tables In Python:: Python representation of symbol tables.
* Lazy Strings In Python:: Python representation of lazy strings.
+* Breakpoints In Python:: Manipulating breakpoints using Python.
@end menu
@node Basic Python
@value{GDBN} automatically @code{import}s the @code{gdb} module for
use in all scripts evaluated by the @code{python} command.
+@findex gdb.PYTHONDIR
+@defvar PYTHONDIR
+A string containing the python directory (@pxref{Python}).
+@end defvar
+
@findex gdb.execute
-@defun execute command [from_tty]
+@defun execute command [from_tty] [to_string]
Evaluate @var{command}, a string, as a @value{GDBN} CLI command.
If a GDB exception happens while @var{command} runs, it is
translated as described in @ref{Exception Handling,,Exception Handling}.
-If no exceptions occur, this function returns @code{None}.
@var{from_tty} specifies whether @value{GDBN} ought to consider this
command as having originated from the user invoking it interactively.
It must be a boolean value. If omitted, it defaults to @code{False}.
+
+By default, any output produced by @var{command} is sent to
+@value{GDBN}'s standard output. If the @var{to_string} parameter is
+@code{True}, then output will be collected by @code{gdb.execute} and
+returned as a string. The default is @code{False}, in which case the
+return value is @code{None}. If @var{to_string} is @code{True}, the
+@value{GDBN} virtual terminal will be temporarily set to unlimited width
+and height, and its pagination will be disabled; @pxref{Screen Size}.
+@end defun
+
+@findex gdb.breakpoints
+@defun breakpoints
+Return a sequence holding all of @value{GDBN}'s breakpoints.
+@xref{Breakpoints In Python}, for more information.
@end defun
@findex gdb.parameter
@samp{print object} is a valid parameter name.
If the named parameter does not exist, this function throws a
-@code{RuntimeError}. Otherwise, the parameter's value is converted to
-a Python value of the appropriate type, and returned.
+@code{gdb.error} (@pxref{Exception Handling}). Otherwise, the
+parameter's value is converted to a Python value of the appropriate
+type, and returned.
@end defun
@findex gdb.history
and count backward from the last element (i.e., the most recent element) to
find the value to return. If @var{number} is zero, then @value{GDBN} will
return the most recent element. If the element specified by @var{number}
-doesn't exist in the value history, a @code{RuntimeError} exception will be
+doesn't exist in the value history, a @code{gdb.error} exception will be
raised.
If no exception is raised, the return value is always an instance of
convenience variable (@pxref{Convenience Vars}) as a @code{gdb.Value}.
@end defun
+@findex gdb.post_event
+@defun post_event event
+Put @var{event}, a callable object taking no arguments, into
+@value{GDBN}'s internal event queue. This callable will be invoked at
+some later point, during @value{GDBN}'s event processing. Events
+posted using @code{post_event} will be run in the order in which they
+were posted; however, there is no way to know when they will be
+processed relative to other events inside @value{GDBN}.
+
+@value{GDBN} is not thread-safe. If your Python program uses multiple
+threads, you must be careful to only call @value{GDBN}-specific
+functions in the main @value{GDBN} thread. @code{post_event} ensures
+this. For example:
+
+@smallexample
+(@value{GDBP}) python
+>import threading
+>
+>class Writer():
+> def __init__(self, message):
+> self.message = message;
+> def __call__(self):
+> gdb.write(self.message)
+>
+>class MyThread1 (threading.Thread):
+> def run (self):
+> gdb.post_event(Writer("Hello "))
+>
+>class MyThread2 (threading.Thread):
+> def run (self):
+> gdb.post_event(Writer("World\n"))
+>
+>MyThread1().start()
+>MyThread2().start()
+>end
+(@value{GDBP}) Hello World
+@end smallexample
+@end defun
+
@findex gdb.write
@defun write string
Print a string to @value{GDBN}'s paginated standard output stream.
never returned.
@end defun
+@findex gdb.solib_name
+@defun solib_name address
+Return the name of the shared library holding the given @var{address}
+as a string, or @code{None}.
+@end defun
+
+@findex gdb.decode_line
+@defun decode_line @r{[}expression@r{]}
+Return locations of the line specified by @var{expression}, or of the
+current line if no argument was given. This function returns a Python
+tuple containing two elements. The first element contains a string
+holding any unparsed section of @var{expression} (or @code{None} if
+the expression has been fully parsed). The second element contains
+either @code{None} or another tuple that contains all the locations
+that match the expression represented as @code{gdb.Symtab_and_line}
+objects (@pxref{Symbol Tables In Python}). If @var{expression} is
+provided, it is decoded the way that @value{GDBN}'s inbuilt
+@code{break} or @code{edit} commands do (@pxref{Specify Location}).
+@end defun
+
@node Exception Handling
@subsubsection Exception Handling
@cindex python exceptions
NameError: name 'foo' is not defined
@end smallexample
-@value{GDBN} errors that happen in @value{GDBN} commands invoked by Python
-code are converted to Python @code{RuntimeError} exceptions. User
-interrupt (via @kbd{C-c} or by typing @kbd{q} at a pagination
-prompt) is translated to a Python @code{KeyboardInterrupt}
-exception. If you catch these exceptions in your Python code, your
-exception handler will see @code{RuntimeError} or
-@code{KeyboardInterrupt} as the exception type, the @value{GDBN} error
-message as its value, and the Python call stack backtrace at the
-Python statement closest to where the @value{GDBN} error occured as the
-traceback.
+@value{GDBN} errors that happen in @value{GDBN} commands invoked by
+Python code are converted to Python exceptions. The type of the
+Python exception depends on the error.
-@node Auto-loading
-@subsubsection Auto-loading
-@cindex auto-loading, Python
+@ftable @code
+@item gdb.error
+This is the base class for most exceptions generated by @value{GDBN}.
+It is derived from @code{RuntimeError}, for compatibility with earlier
+versions of @value{GDBN}.
-When a new object file is read (for example, due to the @code{file}
-command, or because the inferior has loaded a shared library),
-@value{GDBN} will look for a file named @file{@var{objfile}-gdb.py},
-where @var{objfile} is the object file's real name, formed by ensuring
-that the file name is absolute, following all symlinks, and resolving
-@code{.} and @code{..} components. If this file exists and is
-readable, @value{GDBN} will evaluate it as a Python script.
-
-If this file does not exist, and if the parameter
-@code{debug-file-directory} is set (@pxref{Separate Debug Files}),
-then @value{GDBN} will use for its each separated directory component
-@code{component} the file named @file{@code{component}/@var{real-name}}, where
-@var{real-name} is the object file's real name, as described above.
-
-Finally, if this file does not exist, then @value{GDBN} will look for
-a file named @file{@var{data-directory}/python/auto-load/@var{real-name}}, where
-@var{data-directory} is @value{GDBN}'s data directory (available via
-@code{show data-directory}, @pxref{Data Files}), and @var{real-name}
-is the object file's real name, as described above.
-
-When reading an auto-loaded file, @value{GDBN} sets the ``current
-objfile''. This is available via the @code{gdb.current_objfile}
-function (@pxref{Objfiles In Python}). This can be useful for
-registering objfile-specific pretty-printers.
+If an error occurring in @value{GDBN} does not fit into some more
+specific category, then the generated exception will have this type.
-The auto-loading feature is useful for supplying application-specific
-debugging commands and scripts. You can enable or disable this
-feature, and view its current state.
+@item gdb.MemoryError
+This is a subclass of @code{gdb.error} which is thrown when an
+operation tried to access invalid memory in the inferior.
-@table @code
-@kindex maint set python auto-load
-@item maint set python auto-load [yes|no]
-Enable or disable the Python auto-loading feature.
+@item KeyboardInterrupt
+User interrupt (via @kbd{C-c} or by typing @kbd{q} at a pagination
+prompt) is translated to a Python @code{KeyboardInterrupt} exception.
+@end ftable
-@kindex maint show python auto-load
-@item maint show python auto-load
-Show whether Python auto-loading is enabled or disabled.
-@end table
+In all cases, your exception handler will see the @value{GDBN} error
+message as its value and the Python call stack backtrace at the Python
+statement closest to where the @value{GDBN} error occured as the
+traceback.
-@value{GDBN} does not track which files it has already auto-loaded.
-So, your @samp{-gdb.py} file should take care to ensure that it may be
-evaluated multiple times without error.
+@findex gdb.GdbError
+When implementing @value{GDBN} commands in Python via @code{gdb.Command},
+it is useful to be able to throw an exception that doesn't cause a
+traceback to be printed. For example, the user may have invoked the
+command incorrectly. Use the @code{gdb.GdbError} exception
+to handle this case. Example:
+
+@smallexample
+(gdb) python
+>class HelloWorld (gdb.Command):
+> """Greet the whole world."""
+> def __init__ (self):
+> super (HelloWorld, self).__init__ ("hello-world", gdb.COMMAND_OBSCURE)
+> def invoke (self, args, from_tty):
+> argv = gdb.string_to_argv (args)
+> if len (argv) != 0:
+> raise gdb.GdbError ("hello-world takes no arguments")
+> print "Hello, World!"
+>HelloWorld ()
+>end
+(gdb) hello-world 42
+hello-world takes no arguments
+@end smallexample
@node Values From Inferior
@subsubsection Values From Inferior
Again, @code{bar} will also be a @code{gdb.Value} object.
+A @code{gdb.Value} that represents a function can be executed via
+inferior function call. Any arguments provided to the call must match
+the function's prototype, and must be provided in the order specified
+by that prototype.
+
+For example, @code{some_val} is a @code{gdb.Value} instance
+representing a function that takes two integers as arguments. To
+execute this function, call it like so:
+
+@smallexample
+result = some_val (10,20)
+@end smallexample
+
+Any values returned from a function call will be stored as a
+@code{gdb.Value}.
+
The following attributes are provided:
@table @code
@defivar Value type
The type of this @code{gdb.Value}. The value of this attribute is a
-@code{gdb.Type} object.
+@code{gdb.Type} object (@pxref{Types In Python}).
+@end defivar
+
+@defivar Value dynamic_type
+The dynamic type of this @code{gdb.Value}. This uses C@t{++} run-time
+type information (@acronym{RTTI}) to determine the dynamic type of the
+value. If this value is of class type, it will return the class in
+which the value is embedded, if any. If this value is of pointer or
+reference to a class type, it will compute the dynamic type of the
+referenced object, and return a pointer or reference to that type,
+respectively. In all other cases, it will return the value's static
+type.
+
+Note that this feature will only work when debugging a C@t{++} program
+that includes @acronym{RTTI} for the object in question. Otherwise,
+it will just return the static type of the value as in @kbd{ptype foo}
+(@pxref{Symbols, ptype}).
@end defivar
@end table
The following methods are provided:
@table @code
+@defmethod Value __init__ @var{val}
+Many Python values can be converted directly to a @code{gdb.Value} via
+this object initializer. Specifically:
+
+@table @asis
+@item Python boolean
+A Python boolean is converted to the boolean type from the current
+language.
+
+@item Python integer
+A Python integer is converted to the C @code{long} type for the
+current architecture.
+
+@item Python long
+A Python long is converted to the C @code{long long} type for the
+current architecture.
+
+@item Python float
+A Python float is converted to the C @code{double} type for the
+current architecture.
+
+@item Python string
+A Python string is converted to a target string, using the current
+target encoding.
+
+@item @code{gdb.Value}
+If @code{val} is a @code{gdb.Value}, then a copy of the value is made.
+
+@item @code{gdb.LazyString}
+If @code{val} is a @code{gdb.LazyString} (@pxref{Lazy Strings In
+Python}), then the lazy string's @code{value} method is called, and
+its result is used.
+@end table
+@end defmethod
+
@defmethod Value cast type
Return a new instance of @code{gdb.Value} that is the result of
casting this instance to the type described by @var{type}, which must
value pointed to by @code{foo}.
@end defmethod
+@defmethod Value dynamic_cast type
+Like @code{Value.cast}, but works as if the C@t{++} @code{dynamic_cast}
+operator were used. Consult a C@t{++} reference for details.
+@end defmethod
+
+@defmethod Value reinterpret_cast type
+Like @code{Value.cast}, but works as if the C@t{++} @code{reinterpret_cast}
+operator were used. Consult a C@t{++} reference for details.
+@end defmethod
+
@defmethod Value string @r{[}encoding@r{]} @r{[}errors@r{]} @r{[}length@r{]}
If this @code{gdb.Value} represents a string, then this method
converts the contents to a Python string. Otherwise, this method will
@end table
@end defmethod
+@defmethod Type array @var{n1} @r{[}@var{n2}@r{]}
+Return a new @code{gdb.Type} object which represents an array of this
+type. If one argument is given, it is the inclusive upper bound of
+the array; in this case the lower bound is zero. If two arguments are
+given, the first argument is the lower bound of the array, and the
+second argument is the upper bound of the array. An array's length
+must not be negative, but the bounds can be.
+@end defmethod
+
@defmethod Type const
Return a new @code{gdb.Type} object which represents a
@code{const}-qualified variant of this type.
Return a Python @code{Tuple} object that contains two elements: the
low bound of the argument type and the high bound of that type. If
the type does not have a range, @value{GDBN} will raise a
-@code{RuntimeError} exception.
+@code{gdb.error} exception (@pxref{Exception Handling}).
@end defmethod
@defmethod Type reference
convenience functions.
@end table
-@node Pretty Printing
-@subsubsection Pretty Printing
+Further support for types is provided in the @code{gdb.types}
+Python module (@pxref{gdb.types}).
-@value{GDBN} provides a mechanism to allow pretty-printing of values
-using Python code. The pretty-printer API allows application-specific
-code to greatly simplify the display of complex objects. This
-mechanism works for both MI and the CLI.
-
-For example, here is how a C@t{++} @code{std::string} looks without a
-pretty-printer:
-
-@smallexample
-(@value{GDBP}) print s
-$1 = @{
- static npos = 4294967295,
- _M_dataplus = @{
- <std::allocator<char>> = @{
- <__gnu_cxx::new_allocator<char>> = @{<No data fields>@}, <No data fields>@},
- members of std::basic_string<char, std::char_traits<char>, std::allocator<char> >::_Alloc_hider:
- _M_p = 0x804a014 "abcd"
- @}
-@}
-@end smallexample
-
-After a pretty-printer for @code{std::string} has been installed, only
-the contents are printed:
+@node Pretty Printing API
+@subsubsection Pretty Printing API
-@smallexample
-(@value{GDBP}) print s
-$2 = "abcd"
-@end smallexample
+An example output is provided (@pxref{Pretty Printing}).
A pretty-printer is just an object that holds a value and implements a
specific interface, defined here.
pretty-printer. Python scalars (integers, floats, and booleans) and
strings are convertible to @code{gdb.Value}; other types are not.
+Finally, if this method returns @code{None} then no further operations
+are peformed in this method and nothing is printed.
+
If the result is not one of these types, an exception is raised.
@end defop
+@value{GDBN} provides a function which can be used to look up the
+default pretty-printer for a @code{gdb.Value}:
+
+@findex gdb.default_visualizer
+@defun default_visualizer value
+This function takes a @code{gdb.Value} object as an argument. If a
+pretty-printer for this value exists, then it is returned. If no such
+printer exists, then this returns @code{None}.
+@end defun
+
@node Selecting Pretty-Printers
@subsubsection Selecting Pretty-Printers
The Python list @code{gdb.pretty_printers} contains an array of
-functions that have been registered via addition as a pretty-printer.
+functions or callable objects that have been registered via addition
+as a pretty-printer. Printers in this list are called @code{global}
+printers, they're available when debugging all inferiors.
+Each @code{gdb.Progspace} contains a @code{pretty_printers} attribute.
Each @code{gdb.Objfile} also contains a @code{pretty_printers}
attribute.
-A function on one of these lists is passed a single @code{gdb.Value}
+Each function on these lists is passed a single @code{gdb.Value}
argument and should return a pretty-printer object conforming to the
-interface definition above (@pxref{Pretty Printing}). If a function
+interface definition above (@pxref{Pretty Printing API}). If a function
cannot create a pretty-printer for the value, it should return
@code{None}.
@value{GDBN} first checks the @code{pretty_printers} attribute of each
-@code{gdb.Objfile} and iteratively calls each function in the list for
-that @code{gdb.Objfile} until it receives a pretty-printer object.
+@code{gdb.Objfile} in the current program space and iteratively calls
+each enabled lookup routine in the list for that @code{gdb.Objfile}
+until it receives a pretty-printer object.
+If no pretty-printer is found in the objfile lists, @value{GDBN} then
+searches the pretty-printer list of the current program space,
+calling each enabled function until an object is returned.
After these lists have been exhausted, it tries the global
-@code{gdb.pretty-printers} list, again calling each function until an
+@code{gdb.pretty_printers} list, again calling each enabled function until an
object is returned.
The order in which the objfiles are searched is not specified. For a
and iterated over sequentially until the end of the list, or a printer
object is returned.
+For various reasons a pretty-printer may not work.
+For example, the underlying data structure may have changed and
+the pretty-printer is out of date.
+
+The consequences of a broken pretty-printer are severe enough that
+@value{GDBN} provides support for enabling and disabling individual
+printers. For example, if @code{print frame-arguments} is on,
+a backtrace can become highly illegible if any argument is printed
+with a broken printer.
+
+Pretty-printers are enabled and disabled by attaching an @code{enabled}
+attribute to the registered function or callable object. If this attribute
+is present and its value is @code{False}, the printer is disabled, otherwise
+the printer is enabled.
+
+@node Writing a Pretty-Printer
+@subsubsection Writing a Pretty-Printer
+@cindex writing a pretty-printer
+
+A pretty-printer consists of two parts: a lookup function to detect
+if the type is supported, and the printer itself.
+
Here is an example showing how a @code{std::string} printer might be
-written:
+written. @xref{Pretty Printing API}, for details on the API this class
+must provide.
@smallexample
-class StdStringPrinter:
+class StdStringPrinter(object):
"Print a std::string"
- def __init__ (self, val):
+ def __init__(self, val):
self.val = val
- def to_string (self):
+ def to_string(self):
return self.val['_M_dataplus']['_M_p']
- def display_hint (self):
+ def display_hint(self):
return 'string'
@end smallexample
example above might be written.
@smallexample
-def str_lookup_function (val):
-
+def str_lookup_function(val):
lookup_tag = val.type.tag
- regex = re.compile ("^std::basic_string<char,.*>$")
if lookup_tag == None:
return None
- if regex.match (lookup_tag):
- return StdStringPrinter (val)
-
+ regex = re.compile("^std::basic_string<char,.*>$")
+ if regex.match(lookup_tag):
+ return StdStringPrinter(val)
return None
@end smallexample
printers for the specific version of the library used by each
inferior.
-To continue the @code{std::string} example (@pxref{Pretty Printing}),
+To continue the @code{std::string} example (@pxref{Pretty Printing API}),
this code might appear in @code{gdb.libstdcxx.v6}:
@smallexample
-def register_printers (objfile):
- objfile.pretty_printers.add (str_lookup_function)
+def register_printers(objfile):
+ objfile.pretty_printers.add(str_lookup_function)
@end smallexample
@noindent
@smallexample
import gdb.libstdcxx.v6
-gdb.libstdcxx.v6.register_printers (gdb.current_objfile ())
+gdb.libstdcxx.v6.register_printers(gdb.current_objfile())
@end smallexample
+The previous example illustrates a basic pretty-printer.
+There are a few things that can be improved on.
+The printer doesn't have a name, making it hard to identify in a
+list of installed printers. The lookup function has a name, but
+lookup functions can have arbitrary, even identical, names.
+
+Second, the printer only handles one type, whereas a library typically has
+several types. One could install a lookup function for each desired type
+in the library, but one could also have a single lookup function recognize
+several types. The latter is the conventional way this is handled.
+If a pretty-printer can handle multiple data types, then its
+@dfn{subprinters} are the printers for the individual data types.
+
+The @code{gdb.printing} module provides a formal way of solving these
+problems (@pxref{gdb.printing}).
+Here is another example that handles multiple types.
+
+These are the types we are going to pretty-print:
+
+@smallexample
+struct foo @{ int a, b; @};
+struct bar @{ struct foo x, y; @};
+@end smallexample
+
+Here are the printers:
+
+@smallexample
+class fooPrinter:
+ """Print a foo object."""
+
+ def __init__(self, val):
+ self.val = val
+
+ def to_string(self):
+ return ("a=<" + str(self.val["a"]) +
+ "> b=<" + str(self.val["b"]) + ">")
+
+class barPrinter:
+ """Print a bar object."""
+
+ def __init__(self, val):
+ self.val = val
+
+ def to_string(self):
+ return ("x=<" + str(self.val["x"]) +
+ "> y=<" + str(self.val["y"]) + ">")
+@end smallexample
+
+This example doesn't need a lookup function, that is handled by the
+@code{gdb.printing} module. Instead a function is provided to build up
+the object that handles the lookup.
+
+@smallexample
+import gdb.printing
+
+def build_pretty_printer():
+ pp = gdb.printing.RegexpCollectionPrettyPrinter(
+ "my_library")
+ pp.add_printer('foo', '^foo$', fooPrinter)
+ pp.add_printer('bar', '^bar$', barPrinter)
+ return pp
+@end smallexample
+
+And here is the autoload support:
+
+@smallexample
+import gdb.printing
+import my_library
+gdb.printing.register_pretty_printer(
+ gdb.current_objfile(),
+ my_library.build_pretty_printer())
+@end smallexample
+
+Finally, when this printer is loaded into @value{GDBN}, here is the
+corresponding output of @samp{info pretty-printer}:
+
+@smallexample
+(gdb) info pretty-printer
+my_library.so:
+ my_library
+ foo
+ bar
+@end smallexample
+
+@node Inferiors In Python
+@subsubsection Inferiors In Python
+@cindex inferiors in python
+
+@findex gdb.Inferior
+Programs which are being run under @value{GDBN} are called inferiors
+(@pxref{Inferiors and Programs}). Python scripts can access
+information about and manipulate inferiors controlled by @value{GDBN}
+via objects of the @code{gdb.Inferior} class.
+
+The following inferior-related functions are available in the @code{gdb}
+module:
+
+@defun inferiors
+Return a tuple containing all inferior objects.
+@end defun
+
+A @code{gdb.Inferior} object has the following attributes:
+
+@table @code
+@defivar Inferior num
+ID of inferior, as assigned by GDB.
+@end defivar
+
+@defivar Inferior pid
+Process ID of the inferior, as assigned by the underlying operating
+system.
+@end defivar
+
+@defivar Inferior was_attached
+Boolean signaling whether the inferior was created using `attach', or
+started by @value{GDBN} itself.
+@end defivar
+@end table
+
+A @code{gdb.Inferior} object has the following methods:
+
+@table @code
+@defmethod Inferior threads
+This method returns a tuple holding all the threads which are valid
+when it is called. If there are no valid threads, the method will
+return an empty tuple.
+@end defmethod
+
+@findex gdb.read_memory
+@defmethod Inferior read_memory address length
+Read @var{length} bytes of memory from the inferior, starting at
+@var{address}. Returns a buffer object, which behaves much like an array
+or a string. It can be modified and given to the @code{gdb.write_memory}
+function.
+@end defmethod
+
+@findex gdb.write_memory
+@defmethod Inferior write_memory address buffer @r{[}length@r{]}
+Write the contents of @var{buffer} to the inferior, starting at
+@var{address}. The @var{buffer} parameter must be a Python object
+which supports the buffer protocol, i.e., a string, an array or the
+object returned from @code{gdb.read_memory}. If given, @var{length}
+determines the number of bytes from @var{buffer} to be written.
+@end defmethod
+
+@findex gdb.search_memory
+@defmethod Inferior search_memory address length pattern
+Search a region of the inferior memory starting at @var{address} with
+the given @var{length} using the search pattern supplied in
+@var{pattern}. The @var{pattern} parameter must be a Python object
+which supports the buffer protocol, i.e., a string, an array or the
+object returned from @code{gdb.read_memory}. Returns a Python @code{Long}
+containing the address where the pattern was found, or @code{None} if
+the pattern could not be found.
+@end defmethod
+@end table
+
+@node Threads In Python
+@subsubsection Threads In Python
+@cindex threads in python
+
+@findex gdb.InferiorThread
+Python scripts can access information about, and manipulate inferior threads
+controlled by @value{GDBN}, via objects of the @code{gdb.InferiorThread} class.
+
+The following thread-related functions are available in the @code{gdb}
+module:
+
+@findex gdb.selected_thread
+@defun selected_thread
+This function returns the thread object for the selected thread. If there
+is no selected thread, this will return @code{None}.
+@end defun
+
+A @code{gdb.InferiorThread} object has the following attributes:
+
+@table @code
+@defivar InferiorThread num
+ID of the thread, as assigned by GDB.
+@end defivar
+
+@defivar InferiorThread ptid
+ID of the thread, as assigned by the operating system. This attribute is a
+tuple containing three integers. The first is the Process ID (PID); the second
+is the Lightweight Process ID (LWPID), and the third is the Thread ID (TID).
+Either the LWPID or TID may be 0, which indicates that the operating system
+does not use that identifier.
+@end defivar
+@end table
+
+A @code{gdb.InferiorThread} object has the following methods:
+
+@table @code
+@defmethod InferiorThread switch
+This changes @value{GDBN}'s currently selected thread to the one represented
+by this object.
+@end defmethod
+
+@defmethod InferiorThread is_stopped
+Return a Boolean indicating whether the thread is stopped.
+@end defmethod
+
+@defmethod InferiorThread is_running
+Return a Boolean indicating whether the thread is running.
+@end defmethod
+
+@defmethod InferiorThread is_exited
+Return a Boolean indicating whether the thread is exited.
+@end defmethod
+@end table
+
@node Commands In Python
@subsubsection Commands In Python
If this method throws an exception, it is turned into a @value{GDBN}
@code{error} call. Otherwise, the return value is ignored.
+
+@findex gdb.string_to_argv
+To break @var{argument} up into an argv-like string use
+@code{gdb.string_to_argv}. This function behaves identically to
+@value{GDBN}'s internal argument lexer @code{buildargv}.
+It is recommended to use this for consistency.
+Arguments are separated by spaces and may be quoted.
+Example:
+
+@smallexample
+print gdb.string_to_argv ("1 2\ \\\"3 '4 \"5' \"6 '7\"")
+['1', '2 "3', '4 "5', "6 '7"]
+@end smallexample
+
@end defmethod
@cindex completion of Python commands
Python code is read into @value{GDBN}, you may need to import the
@code{gdb} module explicitly.
+@node Parameters In Python
+@subsubsection Parameters In Python
+
+@cindex parameters in python
+@cindex python parameters
+@tindex gdb.Parameter
+@tindex Parameter
+You can implement new @value{GDBN} parameters using Python. A new
+parameter is implemented as an instance of the @code{gdb.Parameter}
+class.
+
+Parameters are exposed to the user via the @code{set} and
+@code{show} commands. @xref{Help}.
+
+There are many parameters that already exist and can be set in
+@value{GDBN}. Two examples are: @code{set follow fork} and
+@code{set charset}. Setting these parameters influences certain
+behavior in @value{GDBN}. Similarly, you can define parameters that
+can be used to influence behavior in custom Python scripts and commands.
+
+@defmethod Parameter __init__ name @var{command-class} @var{parameter-class} @r{[}@var{enum-sequence}@r{]}
+The object initializer for @code{Parameter} registers the new
+parameter with @value{GDBN}. This initializer is normally invoked
+from the subclass' own @code{__init__} method.
+
+@var{name} is the name of the new parameter. If @var{name} consists
+of multiple words, then the initial words are looked for as prefix
+parameters. An example of this can be illustrated with the
+@code{set print} set of parameters. If @var{name} is
+@code{print foo}, then @code{print} will be searched as the prefix
+parameter. In this case the parameter can subsequently be accessed in
+@value{GDBN} as @code{set print foo}.
+
+If @var{name} consists of multiple words, and no prefix parameter group
+can be found, an exception is raised.
+
+@var{command-class} should be one of the @samp{COMMAND_} constants
+(@pxref{Commands In Python}). This argument tells @value{GDBN} how to
+categorize the new parameter in the help system.
+
+@var{parameter-class} should be one of the @samp{PARAM_} constants
+defined below. This argument tells @value{GDBN} the type of the new
+parameter; this information is used for input validation and
+completion.
+
+If @var{parameter-class} is @code{PARAM_ENUM}, then
+@var{enum-sequence} must be a sequence of strings. These strings
+represent the possible values for the parameter.
+
+If @var{parameter-class} is not @code{PARAM_ENUM}, then the presence
+of a fourth argument will cause an exception to be thrown.
+
+The help text for the new parameter is taken from the Python
+documentation string for the parameter's class, if there is one. If
+there is no documentation string, a default value is used.
+@end defmethod
+
+@defivar Parameter set_doc
+If this attribute exists, and is a string, then its value is used as
+the help text for this parameter's @code{set} command. The value is
+examined when @code{Parameter.__init__} is invoked; subsequent changes
+have no effect.
+@end defivar
+
+@defivar Parameter show_doc
+If this attribute exists, and is a string, then its value is used as
+the help text for this parameter's @code{show} command. The value is
+examined when @code{Parameter.__init__} is invoked; subsequent changes
+have no effect.
+@end defivar
+
+@defivar Parameter value
+The @code{value} attribute holds the underlying value of the
+parameter. It can be read and assigned to just as any other
+attribute. @value{GDBN} does validation when assignments are made.
+@end defivar
+
+
+When a new parameter is defined, its type must be specified. The
+available types are represented by constants defined in the @code{gdb}
+module:
+
+@table @code
+@findex PARAM_BOOLEAN
+@findex gdb.PARAM_BOOLEAN
+@item PARAM_BOOLEAN
+The value is a plain boolean. The Python boolean values, @code{True}
+and @code{False} are the only valid values.
+
+@findex PARAM_AUTO_BOOLEAN
+@findex gdb.PARAM_AUTO_BOOLEAN
+@item PARAM_AUTO_BOOLEAN
+The value has three possible states: true, false, and @samp{auto}. In
+Python, true and false are represented using boolean constants, and
+@samp{auto} is represented using @code{None}.
+
+@findex PARAM_UINTEGER
+@findex gdb.PARAM_UINTEGER
+@item PARAM_UINTEGER
+The value is an unsigned integer. The value of 0 should be
+interpreted to mean ``unlimited''.
+
+@findex PARAM_INTEGER
+@findex gdb.PARAM_INTEGER
+@item PARAM_INTEGER
+The value is a signed integer. The value of 0 should be interpreted
+to mean ``unlimited''.
+
+@findex PARAM_STRING
+@findex gdb.PARAM_STRING
+@item PARAM_STRING
+The value is a string. When the user modifies the string, any escape
+sequences, such as @samp{\t}, @samp{\f}, and octal escapes, are
+translated into corresponding characters and encoded into the current
+host charset.
+
+@findex PARAM_STRING_NOESCAPE
+@findex gdb.PARAM_STRING_NOESCAPE
+@item PARAM_STRING_NOESCAPE
+The value is a string. When the user modifies the string, escapes are
+passed through untranslated.
+
+@findex PARAM_OPTIONAL_FILENAME
+@findex gdb.PARAM_OPTIONAL_FILENAME
+@item PARAM_OPTIONAL_FILENAME
+The value is a either a filename (a string), or @code{None}.
+
+@findex PARAM_FILENAME
+@findex gdb.PARAM_FILENAME
+@item PARAM_FILENAME
+The value is a filename. This is just like
+@code{PARAM_STRING_NOESCAPE}, but uses file names for completion.
+
+@findex PARAM_ZINTEGER
+@findex gdb.PARAM_ZINTEGER
+@item PARAM_ZINTEGER
+The value is an integer. This is like @code{PARAM_INTEGER}, except 0
+is interpreted as itself.
+
+@findex PARAM_ENUM
+@findex gdb.PARAM_ENUM
+@item PARAM_ENUM
+The value is a string, which must be one of a collection string
+constants provided when the parameter is created.
+@end table
+
@node Functions In Python
@subsubsection Writing new convenience functions
Python code is read into @value{GDBN}, you may need to import the
@code{gdb} module explicitly.
+@node Progspaces In Python
+@subsubsection Program Spaces In Python
+
+@cindex progspaces in python
+@tindex gdb.Progspace
+@tindex Progspace
+A program space, or @dfn{progspace}, represents a symbolic view
+of an address space.
+It consists of all of the objfiles of the program.
+@xref{Objfiles In Python}.
+@xref{Inferiors and Programs, program spaces}, for more details
+about program spaces.
+
+The following progspace-related functions are available in the
+@code{gdb} module:
+
+@findex gdb.current_progspace
+@defun current_progspace
+This function returns the program space of the currently selected inferior.
+@xref{Inferiors and Programs}.
+@end defun
+
+@findex gdb.progspaces
+@defun progspaces
+Return a sequence of all the progspaces currently known to @value{GDBN}.
+@end defun
+
+Each progspace is represented by an instance of the @code{gdb.Progspace}
+class.
+
+@defivar Progspace filename
+The file name of the progspace as a string.
+@end defivar
+
+@defivar Progspace pretty_printers
+The @code{pretty_printers} attribute is a list of functions. It is
+used to look up pretty-printers. A @code{Value} is passed to each
+function in order; if the function returns @code{None}, then the
+search continues. Otherwise, the return value should be an object
+which is used to format the value. @xref{Pretty Printing API}, for more
+information.
+@end defivar
+
@node Objfiles In Python
@subsubsection Objfiles In Python
used to look up pretty-printers. A @code{Value} is passed to each
function in order; if the function returns @code{None}, then the
search continues. Otherwise, the return value should be an object
-which is used to format the value. @xref{Pretty Printing}, for more
+which is used to format the value. @xref{Pretty Printing API}, for more
information.
@end defivar
stack (@pxref{Frames,,Stack frames}). The @code{gdb.Frame} class
represents a frame in the stack. A @code{gdb.Frame} object is only valid
while its corresponding frame exists in the inferior's stack. If you try
-to use an invalid frame object, @value{GDBN} will throw a @code{RuntimeError}
-exception.
+to use an invalid frame object, @value{GDBN} will throw a @code{gdb.error}
+exception (@pxref{Exception Handling}).
Two @code{gdb.Frame} objects can be compared for equality with the @code{==}
operator, like:
Return the selected frame object. (@pxref{Selection,,Selecting a Frame}).
@end defun
+@findex gdb.newest_frame
+@defun newest_frame
+Return the newest frame object for the selected thread.
+@end defun
+
@defun frame_stop_reason_string reason
Return a string explaining the reason why @value{GDBN} stopped unwinding
frames, as expressed by the given @var{reason} code (an integer, see the
@end defmethod
@defmethod Frame type
-Returns the type of the frame. The value can be one of
-@code{gdb.NORMAL_FRAME}, @code{gdb.DUMMY_FRAME}, @code{gdb.SIGTRAMP_FRAME}
-or @code{gdb.SENTINEL_FRAME}.
+Returns the type of the frame. The value can be one of:
+@table @code
+@item gdb.NORMAL_FRAME
+An ordinary stack frame.
+
+@item gdb.DUMMY_FRAME
+A fake stack frame that was created by @value{GDBN} when performing an
+inferior function call.
+
+@item gdb.INLINE_FRAME
+A frame representing an inlined function. The function was inlined
+into a @code{gdb.NORMAL_FRAME} that is older than this one.
+
+@item gdb.SIGTRAMP_FRAME
+A signal trampoline frame. This is the frame created by the OS when
+it calls into a signal handler.
+
+@item gdb.ARCH_FRAME
+A fake stack frame representing a cross-architecture call.
+
+@item gdb.SENTINEL_FRAME
+This is like @code{gdb.NORMAL_FRAME}, but it is only used for the
+newest frame.
+@end table
@end defmethod
@defmethod Frame unwind_stop_reason
@end defmethod
@end table
+@node Breakpoints In Python
+@subsubsection Manipulating breakpoints using Python
+
+@cindex breakpoints in python
+@tindex gdb.Breakpoint
+
+Python code can manipulate breakpoints via the @code{gdb.Breakpoint}
+class.
+
+@defmethod Breakpoint __init__ spec @r{[}type@r{]} @r{[}wp_class@r{]} @r{[}internal@r{]}
+Create a new breakpoint. @var{spec} is a string naming the
+location of the breakpoint, or an expression that defines a
+watchpoint. The contents can be any location recognized by the
+@code{break} command, or in the case of a watchpoint, by the @code{watch}
+command. The optional @var{type} denotes the breakpoint to create
+from the types defined later in this chapter. This argument can be
+either: @code{BP_BREAKPOINT} or @code{BP_WATCHPOINT}. @var{type}
+defaults to @code{BP_BREAKPOINT}. The optional @var{internal} argument
+allows the breakpoint to become invisible to the user. The breakpoint
+will neither be reported when created, nor will it be listed in the
+output from @code{info breakpoints} (but will be listed with the
+@code{maint info breakpoints} command). The optional @var{wp_class}
+argument defines the class of watchpoint to create, if @var{type} is
+@code{BP_WATCHPOINT}. If a watchpoint class is not provided, it is
+assumed to be a @var{WP_WRITE} class.
+@end defmethod
+
+The available watchpoint types represented by constants are defined in the
+@code{gdb} module:
+
+@table @code
+@findex WP_READ
+@findex gdb.WP_READ
+@item WP_READ
+Read only watchpoint.
+
+@findex WP_WRITE
+@findex gdb.WP_WRITE
+@item WP_WRITE
+Write only watchpoint.
+
+@findex WP_ACCESS
+@findex gdb.WP_ACCESS
+@item WP_ACCESS
+Read/Write watchpoint.
+@end table
+
+@defmethod Breakpoint is_valid
+Return @code{True} if this @code{Breakpoint} object is valid,
+@code{False} otherwise. A @code{Breakpoint} object can become invalid
+if the user deletes the breakpoint. In this case, the object still
+exists, but the underlying breakpoint does not. In the cases of
+watchpoint scope, the watchpoint remains valid even if execution of the
+inferior leaves the scope of that watchpoint.
+@end defmethod
+
+@defmethod Breakpoint delete
+Permanently deletes the @value{GDBN} breakpoint. This also
+invalidates the Python @code{Breakpoint} object. Any further access
+to this object's attributes or methods will raise an error.
+@end defmethod
+
+@defivar Breakpoint enabled
+This attribute is @code{True} if the breakpoint is enabled, and
+@code{False} otherwise. This attribute is writable.
+@end defivar
+
+@defivar Breakpoint silent
+This attribute is @code{True} if the breakpoint is silent, and
+@code{False} otherwise. This attribute is writable.
+
+Note that a breakpoint can also be silent if it has commands and the
+first command is @code{silent}. This is not reported by the
+@code{silent} attribute.
+@end defivar
+
+@defivar Breakpoint thread
+If the breakpoint is thread-specific, this attribute holds the thread
+id. If the breakpoint is not thread-specific, this attribute is
+@code{None}. This attribute is writable.
+@end defivar
+
+@defivar Breakpoint task
+If the breakpoint is Ada task-specific, this attribute holds the Ada task
+id. If the breakpoint is not task-specific (or the underlying
+language is not Ada), this attribute is @code{None}. This attribute
+is writable.
+@end defivar
+
+@defivar Breakpoint ignore_count
+This attribute holds the ignore count for the breakpoint, an integer.
+This attribute is writable.
+@end defivar
+
+@defivar Breakpoint number
+This attribute holds the breakpoint's number --- the identifier used by
+the user to manipulate the breakpoint. This attribute is not writable.
+@end defivar
+
+@defivar Breakpoint type
+This attribute holds the breakpoint's type --- the identifier used to
+determine the actual breakpoint type or use-case. This attribute is not
+writable.
+@end defivar
+
+@defivar Breakpoint visible
+This attribute tells whether the breakpoint is visible to the user
+when set, or when the @samp{info breakpoints} command is run. This
+attribute is not writable.
+@end defivar
+
+The available types are represented by constants defined in the @code{gdb}
+module:
+
+@table @code
+@findex BP_BREAKPOINT
+@findex gdb.BP_BREAKPOINT
+@item BP_BREAKPOINT
+Normal code breakpoint.
+
+@findex BP_WATCHPOINT
+@findex gdb.BP_WATCHPOINT
+@item BP_WATCHPOINT
+Watchpoint breakpoint.
+
+@findex BP_HARDWARE_WATCHPOINT
+@findex gdb.BP_HARDWARE_WATCHPOINT
+@item BP_HARDWARE_WATCHPOINT
+Hardware assisted watchpoint.
+
+@findex BP_READ_WATCHPOINT
+@findex gdb.BP_READ_WATCHPOINT
+@item BP_READ_WATCHPOINT
+Hardware assisted read watchpoint.
+
+@findex BP_ACCESS_WATCHPOINT
+@findex gdb.BP_ACCESS_WATCHPOINT
+@item BP_ACCESS_WATCHPOINT
+Hardware assisted access watchpoint.
+@end table
+
+@defivar Breakpoint hit_count
+This attribute holds the hit count for the breakpoint, an integer.
+This attribute is writable, but currently it can only be set to zero.
+@end defivar
+
+@defivar Breakpoint location
+This attribute holds the location of the breakpoint, as specified by
+the user. It is a string. If the breakpoint does not have a location
+(that is, it is a watchpoint) the attribute's value is @code{None}. This
+attribute is not writable.
+@end defivar
+
+@defivar Breakpoint expression
+This attribute holds a breakpoint expression, as specified by
+the user. It is a string. If the breakpoint does not have an
+expression (the breakpoint is not a watchpoint) the attribute's value
+is @code{None}. This attribute is not writable.
+@end defivar
+
+@defivar Breakpoint condition
+This attribute holds the condition of the breakpoint, as specified by
+the user. It is a string. If there is no condition, this attribute's
+value is @code{None}. This attribute is writable.
+@end defivar
+
+@defivar Breakpoint commands
+This attribute holds the commands attached to the breakpoint. If
+there are commands, this attribute's value is a string holding all the
+commands, separated by newlines. If there are no commands, this
+attribute is @code{None}. This attribute is not writable.
+@end defivar
+
@node Lazy Strings In Python
@subsubsection Python representation of lazy strings.
writable.
@end defivar
+@node Auto-loading
+@subsection Auto-loading
+@cindex auto-loading, Python
+
+When a new object file is read (for example, due to the @code{file}
+command, or because the inferior has loaded a shared library),
+@value{GDBN} will look for Python support scripts in several ways:
+@file{@var{objfile}-gdb.py} and @code{.debug_gdb_scripts} section.
+
+@menu
+* objfile-gdb.py file:: The @file{@var{objfile}-gdb.py} file
+* .debug_gdb_scripts section:: The @code{.debug_gdb_scripts} section
+* Which flavor to choose?::
+@end menu
+
+The auto-loading feature is useful for supplying application-specific
+debugging commands and scripts.
+
+Auto-loading can be enabled or disabled.
+
+@table @code
+@kindex set auto-load-scripts
+@item set auto-load-scripts [yes|no]
+Enable or disable the auto-loading of Python scripts.
+
+@kindex show auto-load-scripts
+@item show auto-load-scripts
+Show whether auto-loading of Python scripts is enabled or disabled.
+@end table
+
+When reading an auto-loaded file, @value{GDBN} sets the
+@dfn{current objfile}. This is available via the @code{gdb.current_objfile}
+function (@pxref{Objfiles In Python}). This can be useful for
+registering objfile-specific pretty-printers.
+
+@node objfile-gdb.py file
+@subsubsection The @file{@var{objfile}-gdb.py} file
+@cindex @file{@var{objfile}-gdb.py}
+
+When a new object file is read, @value{GDBN} looks for
+a file named @file{@var{objfile}-gdb.py},
+where @var{objfile} is the object file's real name, formed by ensuring
+that the file name is absolute, following all symlinks, and resolving
+@code{.} and @code{..} components. If this file exists and is
+readable, @value{GDBN} will evaluate it as a Python script.
+
+If this file does not exist, and if the parameter
+@code{debug-file-directory} is set (@pxref{Separate Debug Files}),
+then @value{GDBN} will look for @var{real-name} in all of the
+directories mentioned in the value of @code{debug-file-directory}.
+
+Finally, if this file does not exist, then @value{GDBN} will look for
+a file named @file{@var{data-directory}/python/auto-load/@var{real-name}}, where
+@var{data-directory} is @value{GDBN}'s data directory (available via
+@code{show data-directory}, @pxref{Data Files}), and @var{real-name}
+is the object file's real name, as described above.
+
+@value{GDBN} does not track which files it has already auto-loaded this way.
+@value{GDBN} will load the associated script every time the corresponding
+@var{objfile} is opened.
+So your @file{-gdb.py} file should be careful to avoid errors if it
+is evaluated more than once.
+
+@node .debug_gdb_scripts section
+@subsubsection The @code{.debug_gdb_scripts} section
+@cindex @code{.debug_gdb_scripts} section
+
+For systems using file formats like ELF and COFF,
+when @value{GDBN} loads a new object file
+it will look for a special section named @samp{.debug_gdb_scripts}.
+If this section exists, its contents is a list of names of scripts to load.
+
+@value{GDBN} will look for each specified script file first in the
+current directory and then along the source search path
+(@pxref{Source Path, ,Specifying Source Directories}),
+except that @file{$cdir} is not searched, since the compilation
+directory is not relevant to scripts.
+
+Entries can be placed in section @code{.debug_gdb_scripts} with,
+for example, this GCC macro:
+
+@example
+/* Note: The "MS" section flags are to remove duplicates. */
+#define DEFINE_GDB_SCRIPT(script_name) \
+ asm("\
+.pushsection \".debug_gdb_scripts\", \"MS\",@@progbits,1\n\
+.byte 1\n\
+.asciz \"" script_name "\"\n\
+.popsection \n\
+");
+@end example
+
+@noindent
+Then one can reference the macro in a header or source file like this:
+
+@example
+DEFINE_GDB_SCRIPT ("my-app-scripts.py")
+@end example
+
+The script name may include directories if desired.
+
+If the macro is put in a header, any application or library
+using this header will get a reference to the specified script.
+
+@node Which flavor to choose?
+@subsubsection Which flavor to choose?
+
+Given the multiple ways of auto-loading Python scripts, it might not always
+be clear which one to choose. This section provides some guidance.
+
+Benefits of the @file{-gdb.py} way:
+
+@itemize @bullet
+@item
+Can be used with file formats that don't support multiple sections.
+
+@item
+Ease of finding scripts for public libraries.
+
+Scripts specified in the @code{.debug_gdb_scripts} section are searched for
+in the source search path.
+For publicly installed libraries, e.g., @file{libstdc++}, there typically
+isn't a source directory in which to find the script.
+
+@item
+Doesn't require source code additions.
+@end itemize
+
+Benefits of the @code{.debug_gdb_scripts} way:
+
+@itemize @bullet
+@item
+Works with static linking.
+
+Scripts for libraries done the @file{-gdb.py} way require an objfile to
+trigger their loading. When an application is statically linked the only
+objfile available is the executable, and it is cumbersome to attach all the
+scripts from all the input libraries to the executable's @file{-gdb.py} script.
+
+@item
+Works with classes that are entirely inlined.
+
+Some classes can be entirely inlined, and thus there may not be an associated
+shared library to attach a @file{-gdb.py} script to.
+
+@item
+Scripts needn't be copied out of the source tree.
+
+In some circumstances, apps can be built out of large collections of internal
+libraries, and the build infrastructure necessary to install the
+@file{-gdb.py} scripts in a place where @value{GDBN} can find them is
+cumbersome. It may be easier to specify the scripts in the
+@code{.debug_gdb_scripts} section as relative paths, and add a path to the
+top of the source tree to the source search path.
+@end itemize
+
+@node Python modules
+@subsection Python modules
+@cindex python modules
+
+@value{GDBN} comes with a module to assist writing Python code.
+
+@menu
+* gdb.printing:: Building and registering pretty-printers.
+* gdb.types:: Utilities for working with types.
+@end menu
+
+@node gdb.printing
+@subsubsection gdb.printing
+@cindex gdb.printing
+
+This module provides a collection of utilities for working with
+pretty-printers.
+
+@table @code
+@item PrettyPrinter (@var{name}, @var{subprinters}=None)
+This class specifies the API that makes @samp{info pretty-printer},
+@samp{enable pretty-printer} and @samp{disable pretty-printer} work.
+Pretty-printers should generally inherit from this class.
+
+@item SubPrettyPrinter (@var{name})
+For printers that handle multiple types, this class specifies the
+corresponding API for the subprinters.
+
+@item RegexpCollectionPrettyPrinter (@var{name})
+Utility class for handling multiple printers, all recognized via
+regular expressions.
+@xref{Writing a Pretty-Printer}, for an example.
+
+@item register_pretty_printer (@var{obj}, @var{printer})
+Register @var{printer} with the pretty-printer list of @var{obj}.
+@end table
+
+@node gdb.types
+@subsubsection gdb.types
+@cindex gdb.types
+
+This module provides a collection of utilities for working with
+@code{gdb.Types} objects.
+
+@table @code
+@item get_basic_type (@var{type})
+Return @var{type} with const and volatile qualifiers stripped,
+and with typedefs and C@t{++} references converted to the underlying type.
+
+C@t{++} example:
+
+@smallexample
+typedef const int const_int;
+const_int foo (3);
+const_int& foo_ref (foo);
+int main () @{ return 0; @}
+@end smallexample
+
+Then in gdb:
+
+@smallexample
+(gdb) start
+(gdb) python import gdb.types
+(gdb) python foo_ref = gdb.parse_and_eval("foo_ref")
+(gdb) python print gdb.types.get_basic_type(foo_ref.type)
+int
+@end smallexample
+
+@item has_field (@var{type}, @var{field})
+Return @code{True} if @var{type}, assumed to be a type with fields
+(e.g., a structure or union), has field @var{field}.
+
+@item make_enum_dict (@var{enum_type})
+Return a Python @code{dictionary} type produced from @var{enum_type}.
+@end table
+
@node Interpreters
@chapter Command Interpreters
@cindex command interpreters
@cindex TUI key bindings
The TUI installs several key bindings in the readline keymaps
-(@pxref{Command Line Editing}). The following key bindings
-are installed for both TUI mode and the @value{GDBN} standard mode.
+@ifset SYSTEM_READLINE
+(@pxref{Command Line Editing, , , rluserman, GNU Readline Library}).
+@end ifset
+@ifclear SYSTEM_READLINE
+(@pxref{Command Line Editing}).
+@end ifclear
+The following key bindings are installed for both TUI mode and the
+@value{GDBN} standard mode.
@table @kbd
@kindex C-x C-a
Function name.
@item @var{file}
File name of the source file where the function lives.
+@item @var{fullname}
+The full file name of the source file where the function lives.
@item @var{line}
Line number corresponding to the @code{$pc}.
+@item @var{from}
+The shared library where this function is defined. This is only given
+if the frame's function is not known.
@end table
If invoked without arguments, this command prints a backtrace for the
@item displayhint
A dynamic varobj can supply a display hint to the front end. The
value comes directly from the Python pretty-printer object's
-@code{display_hint} method. @xref{Pretty Printing}.
+@code{display_hint} method. @xref{Pretty Printing API}.
@end table
Typical output will look like this:
Return a list of the children of the specified variable object and
create variable objects for them, if they do not already exist. With
-a single argument or if @var{print-values} has a value for of 0 or
+a single argument or if @var{print-values} has a value of 0 or
@code{--no-values}, print only the names of the variables; if
@var{print-values} is 1 or @code{--all-values}, also print their
values; and if it is 2 or @code{--simple-values} print the name and
@item displayhint
A dynamic varobj can supply a display hint to the front end. The
value comes directly from the Python pretty-printer object's
-@code{display_hint} method. @xref{Pretty Printing}.
+@code{display_hint} method. @xref{Pretty Printing API}.
@item has_more
This is an integer attribute which is nonzero if there are children
the varobj @var{name} as an argument (this is done so that the same
Python pretty-printing code can be used for both the CLI and MI).
When called, this object must return an object which conforms to the
-pretty-printing interface (@pxref{Pretty Printing}).
+pretty-printing interface (@pxref{Pretty Printing API}).
The pre-defined function @code{gdb.default_visualizer} may be used to
select a visualizer by following the built-in process
@var{start-addr} and @var{end-addr}, only the lines up to @var{end-addr}
are displayed.
@item @var{mode}
-is either 0 (meaning only disassembly) or 1 (meaning mixed source and
-disassembly).
+is either 0 (meaning only disassembly), 1 (meaning mixed source and
+disassembly), 2 (meaning disassembly with raw opcodes), or 3 (meaning
+mixed source and disassembly with raw opcodes).
@end table
@subsubheading Result
@subheading The @code{-data-read-memory} Command
@findex -data-read-memory
+This command is deprecated, use @code{-data-read-memory-bytes} instead.
+
@subsubheading Synopsis
@smallexample
(gdb)
@end smallexample
+@subheading The @code{-data-read-memory-bytes} Command
+@findex -data-read-memory-bytes
+
+@subsubheading Synopsis
+
+@smallexample
+ -data-read-memory-bytes [ -o @var{byte-offset} ]
+ @var{address} @var{count}
+@end smallexample
+
+@noindent
+where:
+
+@table @samp
+@item @var{address}
+An expression specifying the address of the first memory word to be
+read. Complex expressions containing embedded white space should be
+quoted using the C convention.
+
+@item @var{count}
+The number of bytes to read. This should be an integer literal.
+
+@item @var{byte-offset}
+The offsets in bytes relative to @var{address} at which to start
+reading. This should be an integer literal. This option is provided
+so that a frontend is not required to first evaluate address and then
+perform address arithmetics itself.
+
+@end table
+
+This command attempts to read all accessible memory regions in the
+specified range. First, all regions marked as unreadable in the memory
+map (if one is defined) will be skipped. @xref{Memory Region
+Attributes}. Second, @value{GDBN} will attempt to read the remaining
+regions. For each one, if reading full region results in an errors,
+@value{GDBN} will try to read a subset of the region.
+
+In general, every single byte in the region may be readable or not,
+and the only way to read every readable byte is to try a read at
+every address, which is not practical. Therefore, @value{GDBN} will
+attempt to read all accessible bytes at either beginning or the end
+of the region, using a binary division scheme. This heuristic works
+well for reading accross a memory map boundary. Note that if a region
+has a readable range that is neither at the beginning or the end,
+@value{GDBN} will not read it.
+
+The result record (@pxref{GDB/MI Result Records}) that is output of
+the command includes a field named @samp{memory} whose content is a
+list of tuples. Each tuple represent a successfully read memory block
+and has the following fields:
+
+@table @code
+@item begin
+The start address of the memory block, as hexadecimal literal.
+
+@item end
+The end address of the memory block, as hexadecimal literal.
+
+@item offset
+The offset of the memory block, as hexadecimal literal, relative to
+the start address passed to @code{-data-read-memory-bytes}.
+
+@item contents
+The contents of the memory block, in hex.
+
+@end table
+
+
+
+@subsubheading @value{GDBN} Command
+
+The corresponding @value{GDBN} command is @samp{x}.
+
+@subsubheading Example
+
+@smallexample
+(gdb)
+-data-read-memory-bytes &a 10
+^done,memory=[@{begin="0xbffff154",offset="0x00000000",
+ end="0xbffff15e",
+ contents="01000000020000000300"@}]
+(gdb)
+@end smallexample
+
+
+@subheading The @code{-data-write-memory-bytes} Command
+@findex -data-write-memory-bytes
+
+@subsubheading Synopsis
+
+@smallexample
+ -data-write-memory-bytes @var{address} @var{contents}
+@end smallexample
+
+@noindent
+where:
+
+@table @samp
+@item @var{address}
+An expression specifying the address of the first memory word to be
+read. Complex expressions containing embedded white space should be
+quoted using the C convention.
+
+@item @var{contents}
+The hex-encoded bytes to write.
+
+@end table
+
+@subsubheading @value{GDBN} Command
+
+There's no corresponding @value{GDBN} command.
+
+@subsubheading Example
+
+@smallexample
+(gdb)
+-data-write-memory-bytes &a "aabbccdd"
+^done
+(gdb)
+@end smallexample
+
+
@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@node GDB/MI Tracepoint Commands
@section @sc{gdb/mi} Tracepoint Commands
-trace-status
@end smallexample
-Obtains the status of a tracing experiement. The result may include
+Obtains the status of a tracing experiment. The result may include
the following fields:
@table @samp
@samp{passcount}.
@item frames
-This field is an integer number of currently collected frames. This
-field is optional.
+@itemx frames-created
+The @samp{frames} field is a count of the total number of trace frames
+in the trace buffer, while @samp{frames-created} is the total created
+during the run, including ones that were discarded, such as when a
+circular trace buffer filled up. Both fields are optional.
@item buffer-size
@itemx buffer-free
These fields tell the current size of the tracing buffer and the
-remaining space. These field is optional.
+remaining space. These fields are optional.
+
+@item circular
+The value of the circular trace buffer flag. @code{1} means that the
+trace buffer is circular and old trace frames will be discarded if
+necessary to make room, @code{0} means that the trace buffer is linear
+and may fill up.
+
+@item disconnected
+The value of the disconnected tracing flag. @code{1} means that
+tracing will continue after @value{GDBN} disconnects, @code{0} means
+that the trace run will stop.
@end table
@samp{display_hint} field in the output of @code{-var-list-children}
@item thread-info
Indicates presence of the @code{-thread-info} command.
+@item data-read-memory-bytes
+Indicates presense of the @code{-data-read-memory-bytes} and the
+@code{-data-write-memory-bytes} commands.
@end table
execution, which means that @value{GDBN} will accept further commands
while the target is running.
+@item reverse
+Indicates that the target is capable of reverse execution.
+@xref{Reverse Execution}, for more information.
+
@end table
@subheading The @code{-list-thread-groups} Command
@c inc-hist.texinfo
@c Use -I with makeinfo to point to the appropriate directory,
@c environment var TEXINPUTS with TeX.
+@ifclear SYSTEM_READLINE
@include rluser.texi
@include inc-hist.texinfo
+@end ifclear
@node Formatting Documentation
The command @code{maint print raw-registers} includes the contents of
the raw register cache; the command @code{maint print cooked-registers}
-includes the (cooked) value of all registers; and the command
-@code{maint print register-groups} includes the groups that each
+includes the (cooked) value of all registers, including registers which
+aren't available on the target nor visible to user; and the
+command @code{maint print register-groups} includes the groups that each
register is a member of. @xref{Registers,, Registers, gdbint,
@value{GDBN} Internals}.
command prints its name, address in memory, and all of its psymtabs
and symtabs.
+@kindex maint print section-scripts
+@cindex info for known .debug_gdb_scripts-loaded scripts
+@item maint print section-scripts [@var{regexp}]
+Print a dump of scripts specified in the @code{.debug_gdb_section} section.
+If @var{regexp} is specified, only print scripts loaded by object files
+matching @var{regexp}.
+For each script, this command prints its name as specified in the objfile,
+and the full path if known.
+@xref{.debug_gdb_scripts section}.
+
@kindex maint print statistics
@cindex bcache statistics
@item maint print statistics
a recursive definition of the data type as stored in @value{GDBN}'s
data structures, including its flags and contained types.
+@kindex maint set dwarf2 always-disassemble
+@kindex maint show dwarf2 always-disassemble
+@item maint set dwarf2 always-disassemble
+@item maint show dwarf2 always-disassemble
+Control the behavior of @code{info address} when using DWARF debugging
+information.
+
+The default is @code{off}, which means that @value{GDBN} should try to
+describe a variable's location in an easily readable format. When
+@code{on}, @value{GDBN} will instead display the DWARF location
+expression in an assembly-like format. Note that some locations are
+too complex for @value{GDBN} to describe simply; in this case you will
+always see the disassembly form.
+
+Here is an example of the resulting disassembly:
+
+@smallexample
+(gdb) info addr argc
+Symbol "argc" is a complex DWARF expression:
+ 1: DW_OP_fbreg 0
+@end smallexample
+
+For more information on these expressions, see
+@uref{http://www.dwarfstd.org/, the DWARF standard}.
+
@kindex maint set dwarf2 max-cache-age
@kindex maint show dwarf2 max-cache-age
@item maint set dwarf2 max-cache-age
removes a hardware breakpoint or watchpoint, and when the inferior
triggers a hardware-assisted breakpoint or watchpoint.
+@kindex maint set show-all-tib
+@kindex maint show show-all-tib
+@item maint set show-all-tib
+@itemx maint show show-all-tib
+Control whether to show all non zero areas within a 1k block starting
+at thread local base, when using the @samp{info w32 thread-information-block}
+command.
+
@kindex maint space
@cindex memory used by commands
@item maint space
determined by the @value{GDBN} internal gdbarch functions
@code{DEPRECATED_REGISTER_RAW_SIZE} and @code{gdbarch_register_name}. The
specification of several standard @samp{g} packets is specified below.
+
+When reading registers from a trace frame (@pxref{Analyze Collected
+Data,,Using the Collected Data}), the stub may also return a string of
+literal @samp{x}'s in place of the register data digits, to indicate
+that the corresponding register has not been collected, thus its value
+is unavailable. For example, for an architecture with 4 registers of
+4 bytes each, the following reply indicates to @value{GDBN} that
+registers 0 and 2 have not been collected, while registers 1 and 3
+have been collected, and both have zero value:
+
+@smallexample
+-> @code{g}
+<- @code{xxxxxxxx00000000xxxxxxxx00000000}
+@end smallexample
+
@item E @var{NN}
for an error.
@end table
@table @samp
+@item QAllow:@var{op}:@var{val}@dots{}
+@cindex @samp{QAllow} packet
+Specify which operations @value{GDBN} expects to request of the
+target, as a semicolon-separated list of operation name and value
+pairs. Possible values for @var{op} include @samp{WriteReg},
+@samp{WriteMem}, @samp{InsertBreak}, @samp{InsertTrace},
+@samp{InsertFastTrace}, and @samp{Stop}. @var{val} is either 0,
+indicating that @value{GDBN} will not request the operation, or 1,
+indicating that it may. (The target can then use this to set up its
+own internals optimally, for instance if the debugger never expects to
+insert breakpoints, it may not need to install its own trap handler.)
+
@item qC
@cindex current thread, remote request
@cindex @samp{qC} packet
more thread IDs, separated by commas.
@value{GDBN} will respond to each reply with a request for more thread
ids (using the @samp{qs} form of the query), until the target responds
-with @samp{l} (lower-case el, for @dfn{last}).
+with @samp{l} (lower-case ell, for @dfn{last}).
Refer to @ref{thread-id syntax}, for the format of the @var{thread-id}
fields.
An empty reply indicates that @samp{qGetTLSAddr} is not supported by the stub.
@end table
+@item qGetTIBAddr:@var{thread-id}
+@cindex get thread information block address
+@cindex @samp{qGetTIBAddr} packet
+Fetch address of the Windows OS specific Thread Information Block.
+
+@var{thread-id} is the thread ID associated with the thread.
+
+Reply:
+@table @samp
+@item @var{XX}@dots{}
+Hex encoded (big endian) bytes representing the linear address of the
+thread information block.
+
+@item E @var{nn}
+An error occured. This means that either the thread was not found, or the
+address could not be retrieved.
+
+@item
+An empty reply indicates that @samp{qGetTIBAddr} is not supported by the stub.
+@end table
+
@item qL @var{startflag} @var{threadcount} @var{nextthread}
Obtain thread information from RTOS. Where: @var{startflag} (one hex
digit) is one to indicate the first query and zero to indicate a
description. If the stub sees @samp{xmlRegisters=} with target
specific strings separated by a comma, it will report register
description.
+
+@item qRelocInsn
+This feature indicates whether @value{GDBN} supports the
+@samp{qRelocInsn} packet (@pxref{Tracepoint Packets,,Relocate
+instruction reply packet}).
@end table
Stubs should ignore any unknown values for
@tab @samp{-}
@tab Yes
+@item @samp{qXfer:sdata:read}
+@tab No
+@tab @samp{-}
+@tab Yes
+
@item @samp{qXfer:spu:read}
@tab No
@tab @samp{-}
@tab @samp{-}
@tab No
+@item @samp{QAllow}
+@tab No
+@tab @samp{-}
+@tab No
+
@end multitable
These are the currently defined stub features, in more detail:
The remote stub understands the @samp{qXfer:memory-map:read} packet
(@pxref{qXfer memory map read}).
+@item qXfer:sdata:read
+The remote stub understands the @samp{qXfer:sdata:read} packet
+(@pxref{qXfer sdata read}).
+
@item qXfer:spu:read
The remote stub understands the @samp{qXfer:spu:read} packet
(@pxref{qXfer spu read}).
The remote stub understands the @samp{QTDPsrc} packet that supplies
the source form of tracepoint definitions.
+@item QAllow
+The remote stub understands the @samp{QAllow} packet.
+
+@item StaticTracepoint
+@cindex static tracepoints, in remote protocol
+The remote stub supports static tracepoints.
+
@end table
@item qSymbol::
@itemx QTro
@itemx qTStatus
@itemx qTV
+@itemx qTfSTM
+@itemx qTsSTM
+@itemx qTSTMat
@xref{Tracepoint Packets}.
@item qXfer:@var{object}:read:@var{annex}:@var{offset},@var{length}
This packet is not probed by default; the remote stub must request it,
by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}).
+@item qXfer:sdata:read::@var{offset},@var{length}
+@anchor{qXfer sdata read}
+
+Read contents of the extra collected static tracepoint marker
+information. The annex part of the generic @samp{qXfer} packet must
+be empty (@pxref{qXfer read}). @xref{Tracepoint Actions,,Tracepoint
+Action Lists}.
+
+This packet is not probed by default; the remote stub must request it,
+by supplying an appropriate @samp{qSupported} response
+(@pxref{qSupported}).
+
@item qXfer:siginfo:read::@var{offset},@var{length}
@anchor{qXfer siginfo read}
Read contents of the extra signal information on the target
@table @samp
@item OK
The packet was understood and carried out.
+@item qRelocInsn
+@xref{Tracepoint Packets,,Relocate instruction reply packet}.
@item
The packet was not recognized.
@end table
@table @samp
@item OK
The packet was understood and carried out.
+@item qRelocInsn
+@xref{Tracepoint Packets,,Relocate instruction reply packet}.
@item
The packet was not recognized.
@end table
frame @emph{outside} the given range of addresses (exclusive).
@item QTStart
-Begin the tracepoint experiment. Begin collecting data from tracepoint
-hits in the trace frame buffer.
+Begin the tracepoint experiment. Begin collecting data from
+tracepoint hits in the trace frame buffer. This packet supports the
+@samp{qRelocInsn} reply (@pxref{Tracepoint Packets,,Relocate
+instruction reply packet}).
@item QTStop
End the tracepoint experiment. Stop collecting trace frames.
@end table
-Additional optional fields supply statistical information. Although
-not required, they are extremely useful for users monitoring the
-progress of a trace run. If a trace has stopped, and these numbers
-are reported, they must reflect the state of the just-stopped trace.
+Additional optional fields supply statistical and other information.
+Although not required, they are extremely useful for users monitoring
+the progress of a trace run. If a trace has stopped, and these
+numbers are reported, they must reflect the state of the just-stopped
+trace.
@table @samp
@item tfree:@var{n}
The number of bytes still unused in the buffer.
+@item circular:@var{n}
+The value of the circular trace buffer flag. @code{1} means that the
+trace buffer is circular and old trace frames will be discarded if
+necessary to make room, @code{0} means that the trace buffer is linear
+and may fill up.
+
+@item disconn:@var{n}
+The value of the disconnected tracing flag. @code{1} means that
+tracing will continue after @value{GDBN} disconnects, @code{0} means
+that the trace run will stop.
+
@end table
@item qTV:@var{var}
these packets follow the syntax of the @code{QTDV} packets that define
trace state variables.
+@item qTfSTM
+@itemx qTsSTM
+These packets request data about static tracepoint markers that exist
+in the target program. @value{GDBN} sends @code{qTfSTM} to get the
+first piece of data, and multiple @code{qTsSTM} to get additional
+pieces. Replies to these packets take the following form:
+
+Reply:
+@table @samp
+@item m @var{address}:@var{id}:@var{extra}
+A single marker
+@item m @var{address}:@var{id}:@var{extra},@var{address}:@var{id}:@var{extra}@dots{}
+a comma-separated list of markers
+@item l
+(lower case letter @samp{L}) denotes end of list.
+@item E @var{nn}
+An error occurred. @var{nn} are hex digits.
+@item
+An empty reply indicates that the request is not supported by the
+stub.
+@end table
+
+@var{address} is encoded in hex.
+@var{id} and @var{extra} are strings encoded in hex.
+
+In response to each query, the target will reply with a list of one or
+more markers, separated by commas. @value{GDBN} will respond to each
+reply with a request for more markers (using the @samp{qs} form of the
+query), until the target responds with @samp{l} (lower-case ell, for
+@dfn{last}).
+
+@item qTSTMat:@var{address}
+This packets requests data about static tracepoint markers in the
+target program at @var{address}. Replies to this packet follow the
+syntax of the @samp{qTfSTM} and @code{qTsSTM} packets that list static
+tracepoint markers.
+
@item QTSave:@var{filename}
This packet directs the target to save trace data to the file name
@var{filename} in the target's filesystem. @var{filename} is encoded
@end table
+@subsection Relocate instruction reply packet
+When installing fast tracepoints in memory, the target may need to
+relocate the instruction currently at the tracepoint address to a
+different address in memory. For most instructions, a simple copy is
+enough, but, for example, call instructions that implicitly push the
+return address on the stack, and relative branches or other
+PC-relative instructions require offset adjustment, so that the effect
+of executing the instruction at a different address is the same as if
+it had executed in the original location.
+
+In response to several of the tracepoint packets, the target may also
+respond with a number of intermediate @samp{qRelocInsn} request
+packets before the final result packet, to have @value{GDBN} handle
+this relocation operation. If a packet supports this mechanism, its
+documentation will explicitly say so. See for example the above
+descriptions for the @samp{QTStart} and @samp{QTDP} packets. The
+format of the request is:
+
+@table @samp
+@item qRelocInsn:@var{from};@var{to}
+
+This requests @value{GDBN} to copy instruction at address @var{from}
+to address @var{to}, possibly adjusted so that executing the
+instruction at @var{to} has the same effect as executing it at
+@var{from}. @value{GDBN} writes the adjusted instruction to target
+memory starting at @var{to}.
+@end table
+
+Replies:
+@table @samp
+@item qRelocInsn:@var{adjusted_size}
+Informs the stub the relocation is complete. @var{adjusted_size} is
+the length in bytes of resulting relocated instruction sequence.
+@item E @var{NN}
+A badly formed request was detected, or an error was encountered while
+relocating the instruction.
+@end table
+
@node Host I/O Packets
@section Host I/O Packets
@cindex Host I/O, remote protocol
@subsection ARM Features
@cindex target descriptions, ARM features
-The @samp{org.gnu.gdb.arm.core} feature is required for ARM targets.
+The @samp{org.gnu.gdb.arm.core} feature is required for non-M-profile
+ARM targets.
It should contain registers @samp{r0} through @samp{r13}, @samp{sp},
@samp{lr}, @samp{pc}, and @samp{cpsr}.
+For M-profile targets (e.g. Cortex-M3), the @samp{org.gnu.gdb.arm.core}
+feature is replaced by @samp{org.gnu.gdb.arm.m-profile}. It should contain
+registers @samp{r0} through @samp{r13}, @samp{sp}, @samp{lr}, @samp{pc},
+and @samp{xpsr}.
+
The @samp{org.gnu.gdb.arm.fpa} feature is optional. If present, it
should contain registers @samp{f0} through @samp{f7} and @samp{fps}.
The register sets may be different, depending on the target.
-The @samp{org.gnu.gdb.i386.sse} feature is required. It should
+The @samp{org.gnu.gdb.i386.sse} feature is optional. It should
describe registers:
@itemize @minus
@samp{mxcsr}
@end itemize
-The @samp{org.gnu.gdb.i386.avx} feature is optional. It should
+The @samp{org.gnu.gdb.i386.avx} feature is optional and requires the
+@samp{org.gnu.gdb.i386.sse} feature. It should
describe the upper 128 bits of @sc{ymm} registers:
@itemize @minus
@samp{ymm0h} through @samp{ymm7h} for i386
@item
@samp{ymm0h} through @samp{ymm15h} for amd64
-@item
@end itemize
The @samp{org.gnu.gdb.i386.linux} feature is optional. It should
@include gpl.texi
-@raisesections
+@node GNU Free Documentation License
+@appendix GNU Free Documentation License
@include fdl.texi
-@lowersections
@node Index
@unnumbered Index
projects / deliverable / binutils-gdb.git / blobdiff