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
@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},
@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
@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.
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
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.
Python code. It greatly simplifies 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:
+@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
$2 = "abcd"
@end smallexample
-For implementing pretty printers for new types you should read the Python API
-details (@pxref{Pretty Printing API}).
+@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
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}
@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
@code{trace}.
@item strace @var{location} [ if @var{cond} ]
-@cindex static tracepoint, setting
+@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
* 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
@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
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
@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
@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 whenever @value{GDBN} detects
+such pattern in a condition expression. This feature is available in native
+@value{GDBN} running on a Linux kernel version 2.6.34 or newer.
+
@value{GDBN} provides the following PowerPC-specific commands:
@table @code
@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},
+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.
* 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
* Types In Python:: Python representation of types.
* Pretty Printing API:: Pretty-printing values.
* Selecting Pretty-Printers:: How GDB chooses a pretty-printer.
-* Disabling Pretty-Printers:: Disabling broken printers.
+* 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.
@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}.
+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
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
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.
convenience functions.
@end table
+Further support for types is provided in the @code{gdb.types}
+Python module (@pxref{gdb.types}).
+
@node Pretty Printing API
@subsubsection Pretty Printing API
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 or callable objects that have been registered via addition
-as a pretty-printer.
+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 API}). If a function
cannot create a pretty-printer for the value, it should return
@value{GDBN} first checks the @code{pretty_printers} attribute of each
@code{gdb.Objfile} in the current program space and iteratively calls
-each enabled function (@pxref{Disabling Pretty-Printers})
-in the list for that @code{gdb.Objfile} until it receives
-a pretty-printer object.
+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.
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
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
-@node Disabling Pretty-Printers
-@subsubsection Disabling Pretty-Printers
-@cindex disabling pretty-printers
+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.
-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.
+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 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.
+The @code{gdb.printing} module provides a formal way of solving these
+problems (@pxref{gdb.printing}).
+Here is another example that handles multiple types.
-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.
+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
for example, this GCC macro:
@example
-/* Note: The "MS" section flags are to remote duplicates. */
+/* Note: The "MS" section flags are to remove duplicates. */
#define DEFINE_GDB_SCRIPT(script_name) \
asm("\
.pushsection \".debug_gdb_scripts\", \"MS\",@@progbits,1\n\
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
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
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
@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
@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
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.
@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}.
@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
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