\input texinfo @c -*-texinfo-*-
-@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 Copyright (C) 1988-1996, 1998-2012 Free Software Foundation, Inc.
@c
@c %**start of header
@c makeinfo ignores cmds prev to setfilename, so its arg cannot make use
* GDB/MI:: @value{GDBN}'s Machine Interface.
* Annotations:: @value{GDBN}'s annotation interface.
* JIT Interface:: Using the JIT debugging interface.
+* In-Process Agent:: In-Process Agent
* GDB Bugs:: Reporting bugs in @value{GDBN}
-x setbreakpoints -ex 'run' a.out
@end smallexample
+@item -init-command @var{file}
+@itemx -ix @var{file}
+@cindex @code{--init-command}
+@cindex @code{-ix}
+Execute commands from file @var{file} before loading gdbinit files or the
+inferior.
+@xref{Startup}.
+
+@item -init-eval-command @var{command}
+@itemx -iex @var{command}
+@cindex @code{--init-eval-command}
+@cindex @code{-iex}
+Execute a single @value{GDBN} command before loading gdbinit files or the
+inferior.
+@xref{Startup}.
+
@item -directory @var{directory}
@itemx -d @var{directory}
@cindex @code{--directory}
batch mode or quiet mode.
@table @code
+@anchor{-nx}
@item -nx
@itemx -n
@cindex @code{--nx}
Activate the @dfn{Text User Interface} when starting. The Text User
Interface manages several text windows on the terminal, showing
source, assembly, registers and @value{GDBN} command outputs
-(@pxref{TUI, ,@value{GDBN} Text User Interface}). Alternatively, the
-Text User Interface can be enabled by invoking the program
-@samp{@value{GDBTUI}}. Do not use this option if you run @value{GDBN} from
-Emacs (@pxref{Emacs, ,Using @value{GDBN} under @sc{gnu} Emacs}).
+(@pxref{TUI, ,@value{GDBN} Text User Interface}). Do not use this
+option if you run @value{GDBN} from Emacs (@pxref{Emacs, ,
+Using @value{GDBN} under @sc{gnu} Emacs}).
@c @item -xdb
@c @cindex @code{--xdb}
This option causes @value{GDBN} to print its version number and
no-warranty blurb, and exit.
+@item -use-deprecated-index-sections
+@cindex @code{--use-deprecated-index-sections}
+This option causes @value{GDBN} to read and use deprecated
+@samp{.gdb_index} sections from symbol files. This can speed up
+startup, but may result in some functionality being lost.
+@xref{Index Section Format}.
+
@end table
@node Startup
Sets up the command interpreter as specified by the command line
(@pxref{Mode Options, interpreter}).
+@anchor{Option -init-eval-command}
+@item
+Executes commands and command files specified by the @samp{-iex} and
+@samp{-ix} options in their specified order. Usually you should use the
+@samp{-ex} and @samp{-x} options instead, but this way you can apply
+settings before @value{GDBN} init files get executed and before inferior
+gets loaded.
+
@item
@cindex init file
Reads the system-wide @dfn{init file} (if @option{--with-system-gdbinit} was
,System-wide configuration and settings}) and executes all the commands in
that file.
+@anchor{Home Directory Init File}
@item
Reads the init file (if any) in your home directory@footnote{On
DOS/Windows systems, the home directory is the one pointed to by the
@item
Processes command line options and operands.
+@anchor{Init File in the Current Directory during Startup}
@item
Reads and executes the commands from init file (if any) in the current
-working directory. This is only done if the current directory is
+working directory as long as @samp{set auto-load local-gdbinit} is set to
+@samp{on} (@pxref{Init File in the Current Directory}).
+This is only done if the current directory is
different from your home directory. Thus, you can have more than one
init file, one generic in your home directory, and another, specific
to the program you are debugging, in the directory where you invoke
you must do something like the following:
@smallexample
-$ gdb -ex "set auto-load-scripts off" -ex "file myprogram"
+$ gdb -iex "set auto-load python-scripts off" 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
+Option @samp{-ex} does not work because the auto-loading is then turned
+off too late.
@item
-Reads command files specified by the @samp{-x} option. @xref{Command
-Files}, for more details about @value{GDBN} command files.
+Executes commands and command files specified by the @samp{-ex} and
+@samp{-x} options in their specified order. @xref{Command Files}, for
+more details about @value{GDBN} command files.
@item
Reads the command history recorded in the @dfn{history file}.
@table @code
@kindex shell
+@kindex !
@cindex shell escape
-@item shell @var{command string}
-Invoke a standard shell to execute @var{command string}.
+@item shell @var{command-string}
+@itemx !@var{command-string}
+Invoke a standard shell to execute @var{command-string}.
+Note that no space is needed between @code{!} and @var{command-string}.
If it exists, the environment variable @code{SHELL} determines which
shell to run. Otherwise @value{GDBN} uses the default shell
(@file{/bin/sh} on Unix systems, @file{COMMAND.COM} on MS-DOS, etc.).
@var{args}. It prints out all matches found. For example:
@smallexample
-apropos reload
+apropos alias
@end smallexample
@noindent
@smallexample
@c @group
-set symbol-reloading -- Set dynamic symbol table reloading
- multiple times in one run
-show symbol-reloading -- Show dynamic symbol table reloading
- multiple times in one run
+alias -- Define a new command that is an alias of an existing command
+aliases -- Aliases of other commands
+d -- Delete some breakpoints or auto-display expressions
+del -- Delete some breakpoints or auto-display expressions
+delete -- Delete some breakpoints or auto-display expressions
@c @end group
@end smallexample
@xref{Set Watchpoints,,Setting Watchpoints}, for information about
watchpoints in programs with multiple threads.
+@anchor{set libthread-db-search-path}
@table @code
@kindex set libthread-db-search-path
@cindex search path for @code{libthread_db}
On @sc{gnu}/Linux and Solaris systems, @value{GDBN} uses a ``helper''
@code{libthread_db} library to obtain information about threads in the
inferior process. @value{GDBN} will use @samp{libthread-db-search-path}
-to find @code{libthread_db}.
+to find @code{libthread_db}. @value{GDBN} also consults first if inferior
+specific thread debugging library loading is enabled
+by @samp{set auto-load libthread-db} (@pxref{libthread_db.so.1 file}).
A special entry @samp{$sdir} for @samp{libthread-db-search-path}
refers to the default system directories that are
-normally searched for loading shared libraries.
+normally searched for loading shared libraries. The @samp{$sdir} entry
+is the only kind not needing to be enabled by @samp{set auto-load libthread-db}
+(@pxref{libthread_db.so.1 file}).
A special entry @samp{$pdir} for @samp{libthread-db-search-path}
refers to the directory from which @code{libpthread}
* Conditions:: Break conditions
* Break Commands:: Breakpoint command lists
* Save Breakpoints:: How to save breakpoints in a file
+* Static Probe Points:: Listing static probe points
* Error in Breakpoints:: ``Cannot insert breakpoints''
* Breakpoint-related Warnings:: ``Breakpoint address adjusted...''
@end menu
@end table
@noindent
-If a breakpoint is conditional, @code{info break} shows the condition on
-the line following the affected breakpoint; breakpoint commands, if any,
-are listed after that. A pending breakpoint is allowed to have a condition
-specified for it. The condition is not parsed for validity until a shared
-library is loaded that allows the pending breakpoint to resolve to a
-valid location.
+If a breakpoint is conditional, there are two evaluation modes: ``host'' and
+``target''. If mode is ``host'', breakpoint condition evaluation is done by
+@value{GDBN} on the host's side. If it is ``target'', then the condition
+is evaluated by the target. The @code{info break} command shows
+the condition on the line following the affected breakpoint, together with
+its condition evaluation mode in between parentheses.
+
+Breakpoint commands, if any, are listed after that. A pending breakpoint is
+allowed to have a condition specified for it. The condition is not parsed for
+validity until a shared library is loaded that allows the pending
+breakpoint to resolve to a valid location.
@noindent
@code{info break} with a breakpoint
hits, look at the breakpoint info to see how many times the breakpoint
was hit, and then run again, ignoring one less than that number. This
will get you quickly to the last hit of that breakpoint.
+
+@noindent
+For a breakpoints with an enable count (xref) greater than 1,
+@code{info break} also displays that count.
+
@end table
@value{GDBN} allows you to set any number of breakpoints at the same place in
in your program. Examples of this situation are:
@itemize @bullet
+@item
+Multiple functions in the program may have the same name.
+
@item
For a C@t{++} constructor, the @value{NGCC} compiler generates several
instances of the function body, used in different cases.
@end itemize
In all those cases, @value{GDBN} will insert a breakpoint at all
-the relevant locations@footnote{
-As of this writing, multiple-location breakpoints work only if there's
-line number information for all the locations. This means that they
-will generally not work in system libraries, unless you have debug
-info with line numbers for them.}.
+the relevant locations.
A breakpoint with multiple locations is displayed in the breakpoint
table using several rows---one header row, followed by one row for
@code{breakpoint always-inserted} mode is off.
@end table
+@value{GDBN} handles conditional breakpoints by evaluating these conditions
+when a breakpoint breaks. If the condition is true, then the process being
+debugged stops, otherwise the process is resumed.
+
+If the target supports evaluating conditions on its end, @value{GDBN} may
+download the breakpoint, together with its conditions, to it.
+
+This feature can be controlled via the following commands:
+
+@kindex set breakpoint condition-evaluation
+@kindex show breakpoint condition-evaluation
+@table @code
+@item set breakpoint condition-evaluation host
+This option commands @value{GDBN} to evaluate the breakpoint
+conditions on the host's side. Unconditional breakpoints are sent to
+the target which in turn receives the triggers and reports them back to GDB
+for condition evaluation. This is the standard evaluation mode.
+
+@item set breakpoint condition-evaluation target
+This option commands @value{GDBN} to download breakpoint conditions
+to the target at the moment of their insertion. The target
+is responsible for evaluating the conditional expression and reporting
+breakpoint stop events back to @value{GDBN} whenever the condition
+is true. Due to limitations of target-side evaluation, some conditions
+cannot be evaluated there, e.g., conditions that depend on local data
+that is only known to the host. Examples include
+conditional expressions involving convenience variables, complex types
+that cannot be handled by the agent expression parser and expressions
+that are too long to be sent over to the target, specially when the
+target is a remote system. In these cases, the conditions will be
+evaluated by @value{GDBN}.
+
+@item set breakpoint condition-evaluation auto
+This is the default mode. If the target supports evaluating breakpoint
+conditions on its end, @value{GDBN} will download breakpoint conditions to
+the target (limitations mentioned previously apply). If the target does
+not support breakpoint condition evaluation, then @value{GDBN} will fallback
+to evaluating all these conditions on the host's side.
+@end table
+
+
@cindex negative breakpoint numbers
@cindex internal @value{GDBN} breakpoints
@value{GDBN} itself sometimes sets breakpoints in your program for
A call to @code{vfork}. This is currently only available for HP-UX
and @sc{gnu}/Linux.
+@item load @r{[}regexp@r{]}
+@itemx unload @r{[}regexp@r{]}
+The loading or unloading of a shared library. If @var{regexp} is
+given, then the catchpoint will stop only if the regular expression
+matches one of the affected libraries.
+
@end table
@item tcatch @var{event}
Disabling and enabling a breakpoint that has multiple locations
affects all of its locations.
-A breakpoint, watchpoint, or catchpoint can have any of four different
-states of enablement:
+A breakpoint, watchpoint, or catchpoint can have any of several
+different states of enablement:
@itemize @bullet
@item
Enabled once. The breakpoint stops your program, but then becomes
disabled.
@item
+Enabled for a count. The breakpoint stops your program for the next
+N times, then becomes disabled.
+@item
Enabled for deletion. The breakpoint stops your program, but
immediately after it does so it is deleted permanently. A breakpoint
set with the @code{tbreak} command starts out in this state.
Enable the specified breakpoints temporarily. @value{GDBN} disables any
of these breakpoints immediately after stopping your program.
+@item enable @r{[}breakpoints@r{]} count @var{count} @var{range}@dots{}
+Enable the specified breakpoints temporarily. @value{GDBN} records
+@var{count} with each of the specified breakpoints, and decrements a
+breakpoint's count when it is hit. When any count reaches 0,
+@value{GDBN} disables that breakpoint. If a breakpoint has an ignore
+count (@pxref{Conditions, ,Break Conditions}), that will be
+decremented to 0 before @var{count} is affected.
+
@item enable @r{[}breakpoints@r{]} delete @var{range}@dots{}
Enable the specified breakpoints to work once, then die. @value{GDBN}
deletes any of these breakpoints as soon as your program stops there.
purpose of performing side effects when a breakpoint is reached
(@pxref{Break Commands, ,Breakpoint Command Lists}).
+Breakpoint conditions can also be evaluated on the target's side if
+the target supports it. Instead of evaluating the conditions locally,
+@value{GDBN} encodes the expression into an agent expression
+(@pxref{Agent Expressions}) suitable for execution on the target,
+independently of @value{GDBN}. Global variables become raw memory
+locations, locals become stack accesses, and so forth.
+
+In this case, @value{GDBN} will only be notified of a breakpoint trigger
+when its condition evaluates to true. This mechanism may provide faster
+response times depending on the performance characteristics of the target
+since it does not need to keep @value{GDBN} informed about
+every breakpoint trigger, even those with false conditions.
+
Break conditions can be specified when a breakpoint is set, by using
@samp{if} in the arguments to the @code{break} command. @xref{Set
Breaks, ,Setting Breakpoints}. They can also be changed at any time
that can no longer be recreated.
@end table
+@node Static Probe Points
+@subsection Static Probe Points
+
+@cindex static probe point, SystemTap
+@value{GDBN} supports @dfn{SDT} probes in the code. @acronym{SDT} stands
+for Statically Defined Tracing, and the probes are designed to have a tiny
+runtime code and data footprint, and no dynamic relocations. They are
+usable from assembly, C and C@t{++} languages. See
+@uref{http://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation}
+for a good reference on how the @acronym{SDT} probes are implemented.
+
+Currently, @code{SystemTap} (@uref{http://sourceware.org/systemtap/})
+@acronym{SDT} probes are supported on ELF-compatible systems. See
+@uref{http://sourceware.org/systemtap/wiki/AddingUserSpaceProbingToApps}
+for more information on how to add @code{SystemTap} @acronym{SDT} probes
+in your applications.
+
+@cindex semaphores on static probe points
+Some probes have an associated semaphore variable; for instance, this
+happens automatically if you defined your probe using a DTrace-style
+@file{.d} file. If your probe has a semaphore, @value{GDBN} will
+automatically enable it when you specify a breakpoint using the
+@samp{-probe-stap} notation. But, if you put a breakpoint at a probe's
+location by some other method (e.g., @code{break file:line}), then
+@value{GDBN} will not automatically set the semaphore.
+
+You can examine the available static static probes using @code{info
+probes}, with optional arguments:
+
+@table @code
+@kindex info probes
+@item info probes stap @r{[}@var{provider} @r{[}@var{name} @r{[}@var{objfile}@r{]}@r{]}@r{]}
+If given, @var{provider} is a regular expression used to match against provider
+names when selecting which probes to list. If omitted, probes by all
+probes from all providers are listed.
+
+If given, @var{name} is a regular expression to match against probe names
+when selecting which probes to list. If omitted, probe names are not
+considered when deciding whether to display them.
+
+If given, @var{objfile} is a regular expression used to select which
+object files (executable or shared libraries) to examine. If not
+given, all object files are considered.
+
+@item info probes all
+List the available static probes, from all types.
+@end table
+
+@vindex $_probe_arg@r{, convenience variable}
+A probe may specify up to twelve arguments. These are available at the
+point at which the probe is defined---that is, when the current PC is
+at the probe's location. The arguments are available using the
+convenience variables (@pxref{Convenience Vars})
+@code{$_probe_arg0}@dots{}@code{$_probe_arg11}. Each probe argument is
+an integer of the appropriate size; types are not preserved. The
+convenience variable @code{$_probe_argc} holds the number of arguments
+at the current probe point.
+
+These variables are always available, but attempts to access them at
+any location other than a probe point will cause @value{GDBN} to give
+an error message.
+
+
@c @ifclear BARETARGET
@node Error in Breakpoints
@subsection ``Cannot insert breakpoints''
line. These are all variables (declared either static or automatic)
accessible at the point of execution of the selected frame.
-@kindex info catch
-@cindex catch exceptions, list active handlers
-@cindex exception handlers, how to list
-@item info catch
-Print a list of all the exception handlers that are active in the
-current stack frame at the current point of execution. To see other
-exception handlers, visit the associated frame (using the @code{up},
-@code{down}, or @code{frame} commands); then type @code{info catch}.
-@xref{Set Catchpoints, , Setting Catchpoints}.
-
@end table
@item @var{filename}:@var{linenum}
Specifies the line @var{linenum} in the source file @var{filename}.
+If @var{filename} is a relative file name, then it will match any
+source file name with the same trailing components. For example, if
+@var{filename} is @samp{gcc/expr.c}, then it will match source file
+name of @file{/build/trunk/gcc/expr.c}, but not
+@file{/build/trunk/libcpp/expr.c} or @file{/build/trunk/gcc/x-expr.c}.
@item @var{function}
Specifies the line that begins the body of the function @var{function}.
functions with identical names in different source files.
@end table
+@cindex breakpoint at static probe point
+@item -pstap|-probe-stap @r{[}@var{objfile}:@r{[}@var{provider}:@r{]}@r{]}@var{name}
+The @sc{gnu}/Linux tool @code{SystemTap} provides a way for
+applications to embed static probes. @xref{Static Probe Points}, for more
+information on finding and using static probes. This form of linespec
+specifies the location of such a static probe.
+
+If @var{objfile} is given, only probes coming from that shared library
+or executable matching @var{objfile} as a regular expression are considered.
+If @var{provider} is given, then only probes from that provider are considered.
+If several probes match the spec, @value{GDBN} will insert a breakpoint at
+each one of those probes.
+
@end table
command rather than @code{print}. @xref{Symbols, ,Examining the Symbol
Table}.
+@cindex exploring hierarchical data structures
+@kindex explore
+Another way of examining values of expressions and type information is
+through the Python extension command @code{explore} (available only if
+the @value{GDBN} build is configured with @code{--with-python}). It
+offers an interactive way to start at the highest level (or, the most
+abstract level) of the data type of an expression (or, the data type
+itself) and explore all the way down to leaf scalar values/fields
+embedded in the higher level data types.
+
+@table @code
+@item explore @var{arg}
+@var{arg} is either an expression (in the source language), or a type
+visible in the current context of the program being debugged.
+@end table
+
+The working of the @code{explore} command can be illustrated with an
+example. If a data type @code{struct ComplexStruct} is defined in your
+C program as
+
+@smallexample
+struct SimpleStruct
+@{
+ int i;
+ double d;
+@};
+
+struct ComplexStruct
+@{
+ struct SimpleStruct *ss_p;
+ int arr[10];
+@};
+@end smallexample
+
+@noindent
+followed by variable declarations as
+
+@smallexample
+struct SimpleStruct ss = @{ 10, 1.11 @};
+struct ComplexStruct cs = @{ &ss, @{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 @} @};
+@end smallexample
+
+@noindent
+then, the value of the variable @code{cs} can be explored using the
+@code{explore} command as follows.
+
+@smallexample
+(gdb) explore cs
+The value of `cs' is a struct/class of type `struct ComplexStruct' with
+the following fields:
+
+ ss_p = <Enter 0 to explore this field of type `struct SimpleStruct *'>
+ arr = <Enter 1 to explore this field of type `int [10]'>
+
+Enter the field number of choice:
+@end smallexample
+
+@noindent
+Since the fields of @code{cs} are not scalar values, you are being
+prompted to chose the field you want to explore. Let's say you choose
+the field @code{ss_p} by entering @code{0}. Then, since this field is a
+pointer, you will be asked if it is pointing to a single value. From
+the declaration of @code{cs} above, it is indeed pointing to a single
+value, hence you enter @code{y}. If you enter @code{n}, then you will
+be asked if it were pointing to an array of values, in which case this
+field will be explored as if it were an array.
+
+@smallexample
+`cs.ss_p' is a pointer to a value of type `struct SimpleStruct'
+Continue exploring it as a pointer to a single value [y/n]: y
+The value of `*(cs.ss_p)' is a struct/class of type `struct
+SimpleStruct' with the following fields:
+
+ i = 10 .. (Value of type `int')
+ d = 1.1100000000000001 .. (Value of type `double')
+
+Press enter to return to parent value:
+@end smallexample
+
+@noindent
+If the field @code{arr} of @code{cs} was chosen for exploration by
+entering @code{1} earlier, then since it is as array, you will be
+prompted to enter the index of the element in the array that you want
+to explore.
+
+@smallexample
+`cs.arr' is an array of `int'.
+Enter the index of the element you want to explore in `cs.arr': 5
+
+`(cs.arr)[5]' is a scalar value of type `int'.
+
+(cs.arr)[5] = 4
+
+Press enter to return to parent value:
+@end smallexample
+
+In general, at any stage of exploration, you can go deeper towards the
+leaf values by responding to the prompts appropriately, or hit the
+return key to return to the enclosing data structure (the @i{higher}
+level data structure).
+
+Similar to exploring values, you can use the @code{explore} command to
+explore types. Instead of specifying a value (which is typically a
+variable name or an expression valid in the current context of the
+program being debugged), you specify a type name. If you consider the
+same example as above, your can explore the type
+@code{struct ComplexStruct} by passing the argument
+@code{struct ComplexStruct} to the @code{explore} command.
+
+@smallexample
+(gdb) explore struct ComplexStruct
+@end smallexample
+
+@noindent
+By responding to the prompts appropriately in the subsequent interactive
+session, you can explore the type @code{struct ComplexStruct} in a
+manner similar to how the value @code{cs} was explored in the above
+example.
+
+The @code{explore} command also has two sub-commands,
+@code{explore value} and @code{explore type}. The former sub-command is
+a way to explicitly specify that value exploration of the argument is
+being invoked, while the latter is a way to explicitly specify that type
+exploration of the argument is being invoked.
+
+@table @code
+@item explore value @var{expr}
+@cindex explore value
+This sub-command of @code{explore} explores the value of the
+expression @var{expr} (if @var{expr} is an expression valid in the
+current context of the program being debugged). The behavior of this
+command is identical to that of the behavior of the @code{explore}
+command being passed the argument @var{expr}.
+
+@item explore type @var{arg}
+@cindex explore type
+This sub-command of @code{explore} explores the type of @var{arg} (if
+@var{arg} is a type visible in the current context of program being
+debugged), or the type of the value/expression @var{arg} (if @var{arg}
+is an expression valid in the current context of the program being
+debugged). If @var{arg} is a type, then the behavior of this command is
+identical to that of the @code{explore} command being passed the
+argument @var{arg}. If @var{arg} is an expression, then the behavior of
+this command will be identical to that of the @code{explore} command
+being passed the type of @var{arg} as the argument.
+@end table
+
@menu
* Expressions:: Expressions
* Ambiguous Expressions:: Ambiguous Expressions
in this file. But it is possible to have more than one such variable or
function with the same name (in different source files). If that
happens, referring to that name has unpredictable effects. If you wish,
-you can specify a static variable in a particular function or file,
+you can specify a static variable in a particular function or file by
using the colon-colon (@code{::}) notation:
@cindex colon-colon, context for variables/functions
(@value{GDBP}) p 'f2.c'::x
@end smallexample
+The @code{::} notation is normally used for referring to
+static variables, since you typically disambiguate uses of local variables
+in functions by selecting the appropriate frame and using the
+simple name of the variable. However, you may also use this notation
+to refer to local variables in frames enclosing the selected frame:
+
+@smallexample
+void
+foo (int a)
+@{
+ if (a < 10)
+ bar (a);
+ else
+ process (a); /* Stop here */
+@}
+
+int
+bar (int a)
+@{
+ foo (a + 5);
+@}
+@end smallexample
+
+@noindent
+For example, if there is a breakpoint at the commented line,
+here is what you might see
+when the program stops after executing the call @code{bar(0)}:
+
+@smallexample
+(@value{GDBP}) p a
+$1 = 10
+(@value{GDBP}) p bar::a
+$2 = 5
+(@value{GDBP}) up 2
+#2 0x080483d0 in foo (a=5) at foobar.c:12
+(@value{GDBP}) p a
+$3 = 5
+(@value{GDBP}) p bar::a
+$4 = 0
+@end smallexample
+
@cindex C@t{++} scope resolution
-This use of @samp{::} is very rarely in conflict with the very similar
+These uses of @samp{::} are very rarely in conflict with the very similar
use of the same notation in C@t{++}. @value{GDBN} also supports use of the C@t{++}
scope resolution operator in @value{GDBN} expressions.
@c FIXME: Um, so what happens in one of those rare cases where it's in
the virtual function table. Note that the virtual function table is
required---this feature can only work for objects that have run-time
type identification; a single virtual method in the object's declared
-type is sufficient.
+type is sufficient. Note that this setting is also taken into account when
+working with variable objects via MI (@pxref{GDB/MI}).
@item set print object off
Display only the declared type of objects, without reference to the
The variable @code{$_exitcode} is automatically set to the exit code when
the program being debugged terminates.
+@item $_probe_argc
+@itemx $_probe_arg0@dots{}$_probe_arg11
+Arguments to a static probe. @xref{Static Probe Points}.
+
@item $_sdata
@vindex $_sdata@r{, inspect, convenience variable}
The variable @code{$_sdata} contains extra collected static tracepoint
function calls are the same as normal calls:
@itemize @bullet
-@item
-You cannot set breakpoints on inlined functions. @value{GDBN}
-either reports that there is no symbol with that name, or else sets the
-breakpoint only on non-inlined copies of the function. This limitation
-will be removed in a future version of @value{GDBN}; until then,
-set a breakpoint by line number on the first line of the inlined
-function instead.
-
@item
Setting breakpoints at the call site of an inlined function may not
work, because the call site does not contain any code. @value{GDBN}
@cindex macro definition, showing
@cindex definition of a macro, showing
@cindex macros, from debug info
-@item info macro @var{macro}
-Show the current definition of the named @var{macro}, and describe the
-source location or compiler command-line where that definition was established.
+@item info macro [-a|-all] [--] @var{macro}
+Show the current definition or all definitions of the named @var{macro},
+and describe the source location or compiler command-line where that
+definition was established. The optional double dash is to signify the end of
+argument processing and the beginning of @var{macro} for non C-like macros where
+the macro may begin with a hyphen.
@kindex info macros
@item info macros @var{linespec}
by @var{linespec}, and describe the source location or compiler
command-line where those definitions were established.
-@kindex info definitions
-@item info definitions @var{macro}
-Show all definitions of the named @var{macro} that are defined in the current
-compilation unit, and describe the source location or compiler command-line
-where those definitions were established.
-
@kindex macro define
@cindex user-defined macros
@cindex defining macros interactively
@code{trace} command defines a tracepoint, which is a point in the
target program where the debugger will briefly stop, collect some
data, and then allow the program to continue. Setting a tracepoint or
-changing its actions doesn't take effect until the next @code{tstart}
+changing its actions takes effect immediately if the remote stub
+supports the @samp{InstallInTrace} feature (@pxref{install tracepoint
+in tracing}).
+If remote stub doesn't support the @samp{InstallInTrace} feature, all
+these changes don't take effect until the next @code{tstart}
command, and once a trace experiment is running, further changes will
-not have any effect until the next trace experiment starts.
+not have any effect until the next trace experiment starts. In addition,
+@value{GDBN} supports @dfn{pending tracepoints}---tracepoints whose
+address is not yet resolved. (This is similar to pending breakpoints.)
+Pending tracepoints are not downloaded to the target and not installed
+until they are resolved. The resolution of pending tracepoints requires
+@value{GDBN} support---when debugging with the remote target, and
+@value{GDBN} disconnects from the remote stub (@pxref{disconnected
+tracing}), pending tracepoints can not be resolved (and downloaded to
+the remote stub) while @value{GDBN} is disconnected.
Here are some examples of using the @code{trace} command:
@value{GDBN} handles arguments to @code{ftrace} exactly as for
@code{trace}.
+On 32-bit x86-architecture systems, fast tracepoints normally need to
+be placed at an instruction that is 5 bytes or longer, but can be
+placed at 4-byte instructions if the low 64K of memory of the target
+program is available to install trampolines. Some Unix-type systems,
+such as @sc{gnu}/Linux, exclude low addresses from the program's
+address space; but for instance with the Linux kernel it is possible
+to let @value{GDBN} use this area by doing a @command{sysctl} command
+to set the @code{mmap_min_addr} kernel parameter, as in
+
+@example
+sudo sysctl -w vm.mmap_min_addr=32768
+@end example
+
+@noindent
+which sets the low address to 32K, which leaves plenty of room for
+trampolines. The minimum address should be set to a page boundary.
+
@item strace @var{location} [ if @var{cond} ]
@cindex set static tracepoint
@cindex static tracepoints, setting
Collect the return address. This is helpful if you want to see more
of a backtrace.
+@item $_probe_argc
+Collects the number of arguments from the static probe at which the
+tracepoint is located.
+@xref{Static Probe Points}.
+
+@item $_probe_arg@var{n}
+@var{n} is an integer between 0 and 11. Collects the @var{n}th argument
+from the static probe at which the tracepoint is located.
+@xref{Static Probe Points}.
+
@item $_sdata
@vindex $_sdata@r{, collect}
Collect static tracepoint marker specific data. Only available for
@subsection Starting and Stopping Trace Experiments
@table @code
-@kindex tstart
+@kindex tstart [ @var{notes} ]
@cindex start a new trace experiment
@cindex collected data discarded
@item tstart
-This command takes no arguments. It starts the trace experiment, and
-begins collecting data. This has the side effect of discarding all
-the data collected in the trace buffer during the previous trace
-experiment.
-
-@kindex tstop
+This command starts the trace experiment, and begins collecting data.
+It has the side effect of discarding all the data collected in the
+trace buffer during the previous trace experiment. If any arguments
+are supplied, they are taken as a note and stored with the trace
+experiment's state. The notes may be arbitrary text, and are
+especially useful with disconnected tracing in a multi-user context;
+the notes can explain what the trace is doing, supply user contact
+information, and so forth.
+
+@kindex tstop [ @var{notes} ]
@cindex stop a running trace experiment
@item tstop
-This command takes no arguments. It ends the trace experiment, and
-stops collecting data.
+This command stops the trace experiment. If any arguments are
+supplied, they are recorded with the experiment as a note. This is
+useful if you are stopping a trace started by someone else, for
+instance if the trace is interfering with the system's behavior and
+needs to be stopped quickly.
@strong{Note}: a trace experiment and data collection may stop
automatically if any tracepoint's passcount is reached
@end table
+@table @code
+@item set trace-user @var{text}
+@kindex set trace-user
+
+@item show trace-user
+@kindex show trace-user
+
+@item set trace-notes @var{text}
+@kindex set trace-notes
+Set the trace run's notes.
+
+@item show trace-notes
+@kindex show trace-notes
+Show the trace run's notes.
+
+@item set trace-stop-notes @var{text}
+@kindex set trace-stop-notes
+Set the trace run's stop notes. The handling of the note is as for
+@code{tstop} arguments; the set command is convenient way to fix a
+stop note that is mistaken or incomplete.
+
+@item show trace-stop-notes
+@kindex show trace-stop-notes
+Show the trace run's stop notes.
+
+@end table
+
@node Tracepoint Restrictions
@subsection Tracepoint Restrictions
@node Supported Languages
@section Supported Languages
-@value{GDBN} supports C, C@t{++}, D, Objective-C, Fortran, Java, OpenCL C, Pascal,
-assembly, Modula-2, and Ada.
+@value{GDBN} supports C, C@t{++}, D, Go, 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
language you use: the @value{GDBN} @code{@@} and @code{::} operators,
@menu
* C:: C and C@t{++}
* D:: D
+* Go:: Go
* Objective-C:: Objective-C
* OpenCL C:: OpenCL C
* Fortran:: Fortran
@var{typename}.
@xref{Symbols, ,Examining the Symbol Table}.
+@item info vtbl @var{expression}.
+The @code{info vtbl} command can be used to display the virtual
+method tables of the object computed by @var{expression}. This shows
+one entry per virtual table; there may be multiple virtual tables when
+multiple inheritance is in use.
+
@cindex C@t{++} symbol display
@item set print demangle
@itemx show print demangle
GDC, LDC or DMD compilers. Currently @value{GDBN} supports only one D
specific feature --- dynamic arrays.
+@node Go
+@subsection Go
+
+@cindex Go (programming language)
+@value{GDBN} can be used to debug programs written in Go and compiled with
+@file{gccgo} or @file{6g} compilers.
+
+Here is a summary of the Go-specific features and restrictions:
+
+@table @code
+@cindex current Go package
+@item The current Go package
+The name of the current package does not need to be specified when
+specifying global variables and functions.
+
+For example, given the program:
+
+@example
+package main
+var myglob = "Shall we?"
+func main () @{
+ // ...
+@}
+@end example
+
+When stopped inside @code{main} either of these work:
+
+@example
+(gdb) p myglob
+(gdb) p main.myglob
+@end example
+
+@cindex builtin Go types
+@item Builtin Go types
+The @code{string} type is recognized by @value{GDBN} and is printed
+as a string.
+
+@cindex builtin Go functions
+@item Builtin Go functions
+The @value{GDBN} expression parser recognizes the @code{unsafe.Sizeof}
+function and handles it internally.
+
+@cindex restrictions on Go expressions
+@item Restrictions on Go expressions
+All Go operators are supported except @code{&^}.
+The Go @code{_} ``blank identifier'' is not supported.
+Automatic dereferencing of pointers is not supported.
+@end table
+
@node Objective-C
@subsection Objective-C
which match the regular-expression @var{regexp}.
@end ignore
-@cindex reloading symbols
-Some systems allow individual object files that make up your program to
-be replaced without stopping and restarting your program. For example,
-in VxWorks you can simply recompile a defective object file and keep on
-running. If you are running on one of these systems, you can allow
-@value{GDBN} to reload the symbols for automatically relinked modules:
-
-@table @code
-@kindex set symbol-reloading
-@item set symbol-reloading on
-Replace symbol definitions for the corresponding source file when an
-object file with a particular name is seen again.
-
-@item set symbol-reloading off
-Do not replace symbol definitions when encountering object files of the
-same name more than once. This is the default state; if you are not
-running on a system that permits automatic relinking of modules, you
-should leave @code{symbol-reloading} off, since otherwise @value{GDBN}
-may discard symbols when linking large programs, that may contain
-several modules (from different directories or libraries) with the same
-name.
-
-@kindex show symbol-reloading
-@item show symbol-reloading
-Show the current @code{on} or @code{off} setting.
-@end table
-
@cindex opaque data types
@kindex set opaque-type-resolution
@item set opaque-type-resolution on
@end table
Sometimes you may wish that @value{GDBN} stops and gives you control
-when any of shared library events happen. Use the @code{set
-stop-on-solib-events} command for this:
+when any of shared library events happen. The best way to do this is
+to use @code{catch load} and @code{catch unload} (@pxref{Set
+Catchpoints}).
+
+@value{GDBN} also supports the the @code{set stop-on-solib-events}
+command for this. This command exists for historical reasons. It is
+less useful than setting a catchpoint, because it does not allow for
+conditions or commands as a catchpoint does.
@table @code
@item set stop-on-solib-events
@end table
@end table
+@cindex file name canonicalization
+@cindex base name differences
+When processing file names provided by the user, @value{GDBN}
+frequently needs to compare them to the file names recorded in the
+program's debug info. Normally, @value{GDBN} compares just the
+@dfn{base names} of the files as strings, which is reasonably fast
+even for very large programs. (The base name of a file is the last
+portion of its name, after stripping all the leading directories.)
+This shortcut in comparison is based upon the assumption that files
+cannot have more than one base name. This is usually true, but
+references to files that use symlinks or similar filesystem
+facilities violate that assumption. If your program records files
+using such facilities, or if you provide file names to @value{GDBN}
+using symlinks etc., you can set @code{basenames-may-differ} to
+@code{true} to instruct @value{GDBN} to completely canonicalize each
+pair of file names it needs to compare. This will make file-name
+comparisons accurate, but at a price of a significant slowdown.
+
+@table @code
+@item set basenames-may-differ
+@kindex set basenames-may-differ
+Set whether a source file may have multiple base names.
+
+@item show basenames-may-differ
+@kindex show basenames-may-differ
+Show whether a source file may have multiple base names.
+@end table
@node Separate Debug Files
@section Debugging Information in Separate Files
target> gdbserver @var{comm} @var{program} [ @var{args} @dots{} ]
@end smallexample
-@var{comm} is either a device name (to use a serial line) or a TCP
-hostname and portnumber. For example, to debug Emacs with the argument
+@var{comm} is either a device name (to use a serial line), or a TCP
+hostname and portnumber, or @code{-} or @code{stdio} to use
+stdin/stdout of @code{gdbserver}.
+For example, to debug Emacs with the argument
@samp{foo.txt} and communicate with @value{GDBN} over the serial port
@file{/dev/com1}:
and exits.} You must use the same port number with the host @value{GDBN}
@code{target remote} command.
+The @code{stdio} connection is useful when starting @code{gdbserver}
+with ssh:
+
+@smallexample
+(gdb) target remote | ssh -T hostname gdbserver - hello
+@end smallexample
+
+The @samp{-T} option to ssh is provided because we don't need a remote pty,
+and we don't want escape-character handling. Ssh does this by default when
+a command is provided, the flag is provided to make it explicit.
+You could elide it if you want to.
+
+Programs started with stdio-connected gdbserver have @file{/dev/null} for
+@code{stdin}, and @code{stdout},@code{stderr} are sent back to gdb for
+display through a pipe connected to gdbserver.
+Both @code{stdout} and @code{stderr} use the same pipe.
+
@subsubsection Attaching to a Running Program
@cindex attach to a program, @code{gdbserver}
@cindex @option{--attach}, @code{gdbserver} option
@tab @code{QPassSignals}
@tab @code{handle @var{signal}}
+@item @code{program-signals}
+@tab @code{QProgramSignals}
+@tab @code{handle @var{signal}}
+
@item @code{hostio-close-packet}
@tab @code{vFile:close}
@tab @code{remote get}, @code{remote put}
@tab @code{vFile:unlink}
@tab @code{remote delete}
+@item @code{hostio-readlink-packet}
+@tab @code{vFile:readlink}
+@tab Host I/O
+
@item @code{noack-packet}
@tab @code{QStartNoAckMode}
@tab Packet acknowledgment
@tab @code{qXfer:traceframe-info:read}
@tab Traceframe info
+@item @code{install-in-trace}
+@tab @code{InstallInTrace}
+@tab Install tracepoint in tracing
+
@item @code{disable-randomization}
@tab @code{QDisableRandomization}
@tab @code{set disable-randomization}
+
+@item @code{conditional-breakpoints-packet}
+@tab @code{Z0 and Z1}
+@tab @code{Support for target-side breakpoint condition evaluation}
@end multitable
@node Remote Stub
@findex set_debug_traps
@cindex remote serial stub, initialization
This routine arranges for @code{handle_exception} to run when your
-program stops. You must call this subroutine explicitly near the
-beginning of your program.
+program stops. You must call this subroutine explicitly in your
+program's startup code.
@item handle_exception
@findex handle_exception
@end display
@item
-Insert these lines near the top of your program:
+Insert these lines in your program's startup code, before the main
+procedure is called:
@smallexample
set_debug_traps();
breakpoint();
@end smallexample
+On some machines, when a breakpoint trap is raised, the hardware
+automatically makes the PC point to the instruction after the
+breakpoint. If your machine doesn't do that, you may need to adjust
+@code{handle_exception} to arrange for it to return to the instruction
+after the breakpoint on this first invocation, so that your program
+doesn't keep hitting the initial breakpoint instead of making
+progress.
+
@item
For the 680x0 stub only, you need to provide a variable called
@code{exceptionHook}. Normally you just use:
@cindex MIPS boards
@value{GDBN} can use the MIPS remote debugging protocol to talk to a
MIPS board attached to a serial line. This is available when
-you configure @value{GDBN} with @samp{--target=mips-idt-ecoff}.
+you configure @value{GDBN} with @samp{--target=mips-elf}.
@need 1000
Use these @value{GDBN} commands to specify the connection to your target board:
retransmit-timeout @var{seconds}} command. The default is 3 seconds.
You can inspect both values with @code{show timeout} and @code{show
retransmit-timeout}. (These commands are @emph{only} available when
-@value{GDBN} is configured for @samp{--target=mips-idt-ecoff}.)
+@value{GDBN} is configured for @samp{--target=mips-elf}.)
The timeout set by @code{set timeout} does not apply when @value{GDBN}
is waiting for your program to stop. In that case, @value{GDBN} waits
@menu
* i386::
-* A29K::
* Alpha::
* MIPS::
* HPPA:: HP PA architecture
from functions.
@end table
-@node A29K
-@subsection A29K
-
-@table @code
-
-@kindex set rstack_high_address
-@cindex AMD 29K register stack
-@cindex register stack, AMD29K
-@item set rstack_high_address @var{address}
-On AMD 29000 family processors, registers are saved in a separate
-@dfn{register stack}. There is no way for @value{GDBN} to determine the
-extent of this stack. Normally, @value{GDBN} just assumes that the
-stack is ``large enough''. This may result in @value{GDBN} referencing
-memory locations that do not exist. If necessary, you can get around
-this problem by specifying the ending address of the register stack with
-the @code{set rstack_high_address} command. The argument should be an
-address, which you probably want to precede with @samp{0x} to specify in
-hexadecimal.
-
-@kindex show rstack_high_address
-@item show rstack_high_address
-Display the current limit of the register stack, on AMD 29000 family
-processors.
-
-@end table
-
@node Alpha
@subsection Alpha
* Screen Size:: Screen size
* Numbers:: Numbers
* ABI:: Configuring the current ABI
+* Auto-loading:: Automatically loading associated files
* Messages/Warnings:: Optional warnings and messages
* Debugging Output:: Optional messages about internal happenings
* Other Misc Settings:: Other Miscellaneous Settings
Set the current C@t{++} ABI to @var{abi}, or return to automatic detection.
@end table
+@node Auto-loading
+@section Automatically loading associated files
+@cindex auto-loading
+
+@value{GDBN} sometimes reads files with commands and settings automatically,
+without being explicitly told so by the user. We call this feature
+@dfn{auto-loading}. While auto-loading is useful for automatically adapting
+@value{GDBN} to the needs of your project, it can sometimes produce unexpected
+results or introduce security risks (e.g., if the file comes from untrusted
+sources).
+
+For these reasons, @value{GDBN} includes commands and options to let you
+control when to auto-load files and which files should be auto-loaded.
+
+@table @code
+@anchor{set auto-load off}
+@kindex set auto-load off
+@item set auto-load off
+Globally disable loading of all auto-loaded files.
+You may want to use this command with the @samp{-iex} option
+(@pxref{Option -init-eval-command}) such as:
+@smallexample
+$ @kbd{gdb -iex "set auto-load off" untrusted-executable corefile}
+@end smallexample
+
+Be aware that system init file (@pxref{System-wide configuration})
+and init files from your home directory (@pxref{Home Directory Init File})
+still get read (as they come from generally trusted directories).
+To prevent @value{GDBN} from auto-loading even those init files, use the
+@option{-nx} option (@pxref{Mode Options}), in addition to
+@code{set auto-load no}.
+
+@anchor{show auto-load}
+@kindex show auto-load
+@item show auto-load
+Show whether auto-loading of each specific @samp{auto-load} file(s) is enabled
+or disabled.
+
+@smallexample
+(gdb) show auto-load
+gdb-scripts: Auto-loading of canned sequences of commands scripts is on.
+libthread-db: Auto-loading of inferior specific libthread_db is on.
+local-gdbinit: Auto-loading of .gdbinit script from current directory is on.
+python-scripts: Auto-loading of Python scripts is on.
+safe-path: List of directories from which it is safe to auto-load files
+ is /usr/local.
+@end smallexample
+
+@anchor{info auto-load}
+@kindex info auto-load
+@item info auto-load
+Print whether each specific @samp{auto-load} file(s) have been auto-loaded or
+not.
+
+@smallexample
+(gdb) info auto-load
+gdb-scripts:
+Loaded Script
+Yes /home/user/gdb/gdb-gdb.gdb
+libthread-db: No auto-loaded libthread-db.
+local-gdbinit: Local .gdbinit file "/home/user/gdb/.gdbinit" has been loaded.
+python-scripts:
+Loaded Script
+Yes /home/user/gdb/gdb-gdb.py
+@end smallexample
+@end table
+
+These are various kinds of files @value{GDBN} can automatically load:
+
+@itemize @bullet
+@item
+@xref{objfile-gdb.py file}, controlled by @ref{set auto-load python-scripts}.
+@item
+@xref{objfile-gdb.gdb file}, controlled by @ref{set auto-load gdb-scripts}.
+@item
+@xref{dotdebug_gdb_scripts section},
+controlled by @ref{set auto-load python-scripts}.
+@item
+@xref{Init File in the Current Directory},
+controlled by @ref{set auto-load local-gdbinit}.
+@item
+@xref{libthread_db.so.1 file}, controlled by @ref{set auto-load libthread-db}.
+@end itemize
+
+These are @value{GDBN} control commands for the auto-loading:
+
+@multitable @columnfractions .5 .5
+@item @xref{set auto-load off}.
+@tab Disable auto-loading globally.
+@item @xref{show auto-load}.
+@tab Show setting of all kinds of files.
+@item @xref{info auto-load}.
+@tab Show state of all kinds of files.
+@item @xref{set auto-load gdb-scripts}.
+@tab Control for @value{GDBN} command scripts.
+@item @xref{show auto-load gdb-scripts}.
+@tab Show setting of @value{GDBN} command scripts.
+@item @xref{info auto-load gdb-scripts}.
+@tab Show state of @value{GDBN} command scripts.
+@item @xref{set auto-load python-scripts}.
+@tab Control for @value{GDBN} Python scripts.
+@item @xref{show auto-load python-scripts}.
+@tab Show setting of @value{GDBN} Python scripts.
+@item @xref{info auto-load python-scripts}.
+@tab Show state of @value{GDBN} Python scripts.
+@item @xref{set auto-load local-gdbinit}.
+@tab Control for init file in the current directory.
+@item @xref{show auto-load local-gdbinit}.
+@tab Show setting of init file in the current directory.
+@item @xref{info auto-load local-gdbinit}.
+@tab Show state of init file in the current directory.
+@item @xref{set auto-load libthread-db}.
+@tab Control for thread debugging library.
+@item @xref{show auto-load libthread-db}.
+@tab Show setting of thread debugging library.
+@item @xref{info auto-load libthread-db}.
+@tab Show state of thread debugging library.
+@item @xref{set auto-load safe-path}.
+@tab Control directories trusted for automatic loading.
+@item @xref{show auto-load safe-path}.
+@tab Show directories trusted for automatic loading.
+@item @xref{add-auto-load-safe-path}.
+@tab Add directory trusted for automatic loading.
+@end multitable
+
+@menu
+* Init File in the Current Directory:: @samp{set/show/info auto-load local-gdbinit}
+* libthread_db.so.1 file:: @samp{set/show/info auto-load libthread-db}
+* objfile-gdb.gdb file:: @samp{set/show/info auto-load gdb-script}
+* Auto-loading safe path:: @samp{set/show/info auto-load safe-path}
+* Auto-loading verbose mode:: @samp{set/show debug auto-load}
+@xref{Python Auto-loading}.
+@end menu
+
+@node Init File in the Current Directory
+@subsection Automatically loading init file in the current directory
+@cindex auto-loading init file in the current directory
+
+By default, @value{GDBN} reads and executes the canned sequences of commands
+from init file (if any) in the current working directory,
+see @ref{Init File in the Current Directory during Startup}.
+
+@table @code
+@anchor{set auto-load local-gdbinit}
+@kindex set auto-load local-gdbinit
+@item set auto-load local-gdbinit [on|off]
+Enable or disable the auto-loading of canned sequences of commands
+(@pxref{Sequences}) found in init file in the current directory.
+
+@anchor{show auto-load local-gdbinit}
+@kindex show auto-load local-gdbinit
+@item show auto-load local-gdbinit
+Show whether auto-loading of canned sequences of commands from init file in the
+current directory is enabled or disabled.
+
+@anchor{info auto-load local-gdbinit}
+@kindex info auto-load local-gdbinit
+@item info auto-load local-gdbinit
+Print whether canned sequences of commands from init file in the
+current directory have been auto-loaded.
+@end table
+
+@node libthread_db.so.1 file
+@subsection Automatically loading thread debugging library
+@cindex auto-loading libthread_db.so.1
+
+This feature is currently present only on @sc{gnu}/Linux native hosts.
+
+@value{GDBN} reads in some cases thread debugging library from places specific
+to the inferior (@pxref{set libthread-db-search-path}).
+
+The special @samp{libthread-db-search-path} entry @samp{$sdir} is processed
+without checking this @samp{set auto-load libthread-db} switch as system
+libraries have to be trusted in general. In all other cases of
+@samp{libthread-db-search-path} entries @value{GDBN} checks first if @samp{set
+auto-load libthread-db} is enabled before trying to open such thread debugging
+library.
+
+@table @code
+@anchor{set auto-load libthread-db}
+@kindex set auto-load libthread-db
+@item set auto-load libthread-db [on|off]
+Enable or disable the auto-loading of inferior specific thread debugging library.
+
+@anchor{show auto-load libthread-db}
+@kindex show auto-load libthread-db
+@item show auto-load libthread-db
+Show whether auto-loading of inferior specific thread debugging library is
+enabled or disabled.
+
+@anchor{info auto-load libthread-db}
+@kindex info auto-load libthread-db
+@item info auto-load libthread-db
+Print the list of all loaded inferior specific thread debugging libraries and
+for each such library print list of inferior @var{pid}s using it.
+@end table
+
+@node objfile-gdb.gdb file
+@subsection The @file{@var{objfile}-gdb.gdb} file
+@cindex auto-loading @file{@var{objfile}-gdb.gdb}
+
+@value{GDBN} tries to load an @file{@var{objfile}-gdb.gdb} file containing
+canned sequences of commands (@pxref{Sequences}), as long as @samp{set
+auto-load gdb-scripts} is set to @samp{on}.
+
+For more background refer to the similar Python scripts auto-loading
+description (@pxref{objfile-gdb.py file}).
+
+@table @code
+@anchor{set auto-load gdb-scripts}
+@kindex set auto-load gdb-scripts
+@item set auto-load gdb-scripts [on|off]
+Enable or disable the auto-loading of canned sequences of commands scripts.
+
+@anchor{show auto-load gdb-scripts}
+@kindex show auto-load gdb-scripts
+@item show auto-load gdb-scripts
+Show whether auto-loading of canned sequences of commands scripts is enabled or
+disabled.
+
+@anchor{info auto-load gdb-scripts}
+@kindex info auto-load gdb-scripts
+@cindex print list of auto-loaded canned sequences of commands scripts
+@item info auto-load gdb-scripts [@var{regexp}]
+Print the list of all canned sequences of commands scripts that @value{GDBN}
+auto-loaded.
+@end table
+
+If @var{regexp} is supplied only canned sequences of commands scripts with
+matching names are printed.
+
+@node Auto-loading safe path
+@subsection Security restriction for auto-loading
+@cindex auto-loading safe-path
+
+As the files of inferior can come from untrusted source (such as submitted by
+an application user) @value{GDBN} does not always load any files automatically.
+@value{GDBN} provides the @samp{set auto-load safe-path} setting to list
+directories trusted for loading files not explicitly requested by user.
+
+If the path is not set properly you will see a warning and the file will not
+get loaded:
+
+@smallexample
+$ ./gdb -q ./gdb
+Reading symbols from /home/user/gdb/gdb...done.
+warning: File "/home/user/gdb/gdb-gdb.gdb" auto-loading has been
+ declined by your `auto-load safe-path' set to "/usr/local".
+warning: File "/home/user/gdb/gdb-gdb.py" auto-loading has been
+ declined by your `auto-load safe-path' set to "/usr/local".
+@end smallexample
+
+The list of trusted directories is controlled by the following commands:
+
+@table @code
+@anchor{set auto-load safe-path}
+@kindex set auto-load safe-path
+@item set auto-load safe-path @r{[}@var{directories}@r{]}
+Set the list of directories (and their subdirectories) trusted for automatic
+loading and execution of scripts. You can also enter a specific trusted file.
+If you omit @var{directories}, @samp{auto-load safe-path} will be reset to
+its default value as specified during @value{GDBN} compilation.
+
+The list of directories uses directory separator (@samp{:} on GNU and Unix
+systems, @samp{;} on MS-Windows and MS-DOS) to separate directories, similarly
+to the @env{PATH} environment variable.
+
+@anchor{show auto-load safe-path}
+@kindex show auto-load safe-path
+@item show auto-load safe-path
+Show the list of directories trusted for automatic loading and execution of
+scripts.
+
+@anchor{add-auto-load-safe-path}
+@kindex add-auto-load-safe-path
+@item add-auto-load-safe-path
+Add an entry (or list of entries) the list of directories trusted for automatic
+loading and execution of scripts. Multiple entries may be delimited by the
+host platform directory separator in use.
+@end table
+
+Setting this variable to @file{/} disables this security protection.
+This variable is supposed to be set to the system directories writable by the
+system superuser only. Users can add their source directories in init files in
+their home directories (@pxref{Home Directory Init File}). See also deprecated
+init file in the current directory
+(@pxref{Init File in the Current Directory during Startup}).
+
+To force @value{GDBN} to load the files it declined to load in the previous
+example, you could use one of the following ways:
+
+@table @asis
+@item @file{~/.gdbinit}: @samp{add-auto-load-safe-path ~/src/gdb}
+Specify this trusted directory (or a file) as additional component of the list.
+You have to specify also any existing directories displayed by
+by @samp{show auto-load safe-path} (such as @samp{/usr:/bin} in this example).
+
+@item @kbd{gdb -iex "set auto-load safe-path /usr:/bin:~/src/gdb" @dots{}}
+Specify this directory as in the previous case but just for a single
+@value{GDBN} session.
+
+@item @kbd{gdb -iex "set auto-load safe-path /" @dots{}}
+Disable auto-loading safety for a single @value{GDBN} session.
+This assumes all the files you debug during this @value{GDBN} session will come
+from trusted sources.
+
+@item @kbd{./configure --without-auto-load-safe-path}
+During compilation of @value{GDBN} you may disable any auto-loading safety.
+This assumes all the files you will ever debug with this @value{GDBN} come from
+trusted sources.
+@end table
+
+On the other hand you can also explicitly forbid automatic files loading which
+also suppresses any such warning messages:
+
+@table @asis
+@item @kbd{gdb -iex "set auto-load no" @dots{}}
+You can use @value{GDBN} command-line option for a single @value{GDBN} session.
+
+@item @file{~/.gdbinit}: @samp{set auto-load no}
+Disable auto-loading globally for the user
+(@pxref{Home Directory Init File}). While it is improbable, you could also
+use system init file instead (@pxref{System-wide configuration}).
+@end table
+
+This setting applies to the file names as entered by user. If no entry matches
+@value{GDBN} tries as a last resort to also resolve all the file names into
+their canonical form (typically resolving symbolic links) and compare the
+entries again. @value{GDBN} already canonicalizes most of the filenames on its
+own before starting the comparison so a canonical form of directories is
+recommended to be entered.
+
+@node Auto-loading verbose mode
+@subsection Displaying files tried for auto-load
+@cindex auto-loading verbose mode
+
+For better visibility of all the file locations where you can place scripts to
+be auto-loaded with inferior --- or to protect yourself against accidental
+execution of untrusted scripts --- @value{GDBN} provides a feature for printing
+all the files attempted to be loaded. Both existing and non-existing files may
+be printed.
+
+For example the list of directories from which it is safe to auto-load files
+(@pxref{Auto-loading safe path}) applies also to canonicalized filenames which
+may not be too obvious while setting it up.
+
+@smallexample
+(gdb) set debug auto-load on
+(gdb) file ~/src/t/true
+auto-load: Loading canned sequences of commands script "/tmp/true-gdb.gdb"
+ for objfile "/tmp/true".
+auto-load: Updating directories of "/usr:/opt".
+auto-load: Using directory "/usr".
+auto-load: Using directory "/opt".
+warning: File "/tmp/true-gdb.gdb" auto-loading has been declined
+ by your `auto-load safe-path' set to "/usr:/opt".
+@end smallexample
+
+@table @code
+@anchor{set debug auto-load}
+@kindex set debug auto-load
+@item set debug auto-load [on|off]
+Set whether to print the filenames attempted to be auto-loaded.
+
+@anchor{show debug auto-load}
+@kindex show debug auto-load
+@item show debug auto-load
+Show whether printing of the filenames attempted to be auto-loaded is turned
+on or off.
+@end table
+
@node Messages/Warnings
@section Optional Warnings and Messages
@kindex help user-defined
@item help user-defined
-List all user-defined commands, with the first line of the documentation
-(if any) for each.
+List all user-defined commands and all python commands defined in class
+COMAND_USER. The first line of the documentation or docstring is
+included (if any).
@kindex show user
@item show user
Display the @value{GDBN} commands used to define @var{commandname} (but
not its documentation). If no @var{commandname} is given, display the
definitions for all user-defined commands.
+This does not work for user-defined python commands.
@cindex infinite recursion in user-defined commands
@kindex show max-user-call-depth
The value of @code{max-user-call-depth} controls how many recursion
levels are allowed in user-defined commands before @value{GDBN} suspects an
infinite recursion and aborts the command.
+This does not apply to user-defined python commands.
@end table
In addition to the above commands, user-defined commands frequently
@menu
* Python Commands:: Accessing Python from @value{GDBN}.
* Python API:: Accessing @value{GDBN} from Python.
-* Auto-loading:: Automatically loading Python code.
+* Python Auto-loading:: Automatically loading Python code.
* Python modules:: Python modules provided by @value{GDBN}.
@end menu
23
@end smallexample
-@kindex maint set python print-stack
-@item maint set python print-stack
-This command is now deprecated. Instead use @code{set python
-print-stack}
-
@kindex set python print-stack
@item set python print-stack
-By default, @value{GDBN} will not print a stack trace when an error
-occurs in a Python script. This can be controlled using @code{set
-python print-stack}: if @code{on}, then Python stack printing is
-enabled; if @code{off}, the default, then Python stack printing is
-disabled.
+By default, @value{GDBN} will print only the message component of a
+Python exception when an error occurs in a Python script. This can be
+controlled using @code{set python print-stack}: if @code{full}, then
+full Python stack printing is enabled; if @code{none}, then Python stack
+and message printing is disabled; if @code{message}, the default, only
+the message component of the error is printed.
@end table
It is also possible to execute a Python script from the @value{GDBN}
* 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.
+* Finish Breakpoints in Python:: Setting Breakpoints on function return
+ using Python.
@end menu
@node Basic Python
>class HelloWorld (gdb.Command):
> """Greet the whole world."""
> def __init__ (self):
-> super (HelloWorld, self).__init__ ("hello-world", gdb.COMMAND_OBSCURE)
+> super (HelloWorld, self).__init__ ("hello-world", gdb.COMMAND_USER)
> def invoke (self, args, from_tty):
> argv = gdb.string_to_argv (args)
> if len (argv) != 0:
The result @code{bar} will be a @code{gdb.Value} object holding the
value pointed to by @code{foo}.
+
+A similar function @code{Value.referenced_value} exists which also
+returns @code{gdb.Value} objects corresonding to the values pointed to
+by pointer values (and additionally, values referenced by reference
+values). However, the behavior of @code{Value.dereference}
+differs from @code{Value.referenced_value} by the fact that the
+behavior of @code{Value.dereference} is identical to applying the C
+unary operator @code{*} on a given value. For example, consider a
+reference to a pointer @code{ptrref}, declared in your C@t{++} program
+as
+
+@smallexample
+typedef int *intptr;
+...
+int val = 10;
+intptr ptr = &val;
+intptr &ptrref = ptr;
+@end smallexample
+
+Though @code{ptrref} is a reference value, one can apply the method
+@code{Value.dereference} to the @code{gdb.Value} object corresponding
+to it and obtain a @code{gdb.Value} which is identical to that
+corresponding to @code{val}. However, if you apply the method
+@code{Value.referenced_value}, the result would be a @code{gdb.Value}
+object identical to that corresponding to @code{ptr}.
+
+@smallexample
+py_ptrref = gdb.parse_and_eval ("ptrref")
+py_val = py_ptrref.dereference ()
+py_ptr = py_ptrref.referenced_value ()
+@end smallexample
+
+The @code{gdb.Value} object @code{py_val} is identical to that
+corresponding to @code{val}, and @code{py_ptr} is identical to that
+corresponding to @code{ptr}. In general, @code{Value.dereference} can
+be applied whenever the C unary operator @code{*} can be applied
+to the corresponding C value. For those cases where applying both
+@code{Value.dereference} and @code{Value.referenced_value} is allowed,
+the results obtained need not be identical (as we have seen in the above
+example). The results are however identical when applied on
+@code{gdb.Value} objects corresponding to pointers (@code{gdb.Value}
+objects with type code @code{TYPE_CODE_PTR}) in a C/C@t{++} program.
+@end defun
+
+@defun Value.referenced_value ()
+For pointer or reference data types, this method returns a new
+@code{gdb.Value} object corresponding to the value referenced by the
+pointer/reference value. For pointer data types,
+@code{Value.dereference} and @code{Value.referenced_value} produce
+identical results. The difference between these methods is that
+@code{Value.dereference} cannot get the values referenced by reference
+values. For example, consider a reference to an @code{int}, declared
+in your C@t{++} program as
+
+@smallexample
+int val = 10;
+int &ref = val;
+@end smallexample
+
+@noindent
+then applying @code{Value.dereference} to the @code{gdb.Value} object
+corresponding to @code{ref} will result in an error, while applying
+@code{Value.referenced_value} will result in a @code{gdb.Value} object
+identical to that corresponding to @code{val}.
+
+@smallexample
+py_ref = gdb.parse_and_eval ("ref")
+er_ref = py_ref.dereference () # Results in error
+py_val = py_ref.referenced_value () # Returns the referenced value
+@end smallexample
+
+The @code{gdb.Value} object @code{py_val} is identical to that
+corresponding to @code{val}.
@end defun
@defun Value.dynamic_cast (type)
your pretty-printers at the same time, because they will have
different names.
-You should write auto-loaded code (@pxref{Auto-loading}) such that it
+You should write auto-loaded code (@pxref{Python Auto-loading}) such that it
can be evaluated multiple times without changing its meaning. An
ideal auto-load file will consist solely of @code{import}s of your
printer modules, followed by a call to a register pretty-printers with
@smallexample
def register_printers(objfile):
- objfile.pretty_printers.add(str_lookup_function)
+ objfile.pretty_printers.append(str_lookup_function)
@end smallexample
@noindent
@kbd{help tracepoints} at the @value{GDBN} prompt to see a list of
commands in this category.
+@findex COMMAND_USER
+@findex gdb.COMMAND_USER
+@item gdb.COMMAND_USER
+The command is a general purpose command for the user, and typically
+does not fit in one of the other categories.
+Type @kbd{help user-defined} at the @value{GDBN} prompt to see
+a list of commands in this category, as well as the list of gdb macros
+(@pxref{Sequences}).
+
@findex COMMAND_OBSCURE
@findex gdb.COMMAND_OBSCURE
@item gdb.COMMAND_OBSCURE
"""Greet the whole world."""
def __init__ (self):
- super (HelloWorld, self).__init__ ("hello-world", gdb.COMMAND_OBSCURE)
+ super (HelloWorld, self).__init__ ("hello-world", gdb.COMMAND_USER)
def invoke (self, arg, from_tty):
print "Hello, World!"
@findex gdb.current_objfile
@defun gdb.current_objfile ()
-When auto-loading a Python script (@pxref{Auto-loading}), @value{GDBN}
+When auto-loading a Python script (@pxref{Python Auto-loading}), @value{GDBN}
sets the ``current objfile'' to the corresponding objfile. This
function returns the current objfile. If there is no current objfile,
this function returns @code{None}.
detailed technical information on @value{GDBN}'s book-keeping of the
stack.
+A @code{gdb.Block} is iterable. The iterator returns the symbols
+(@pxref{Symbols In Python}) local to the block. Python programs
+should not assume that a specific block object will always contain a
+given symbol, since changes in @value{GDBN} features and
+infrastructure may cause symbols move across blocks in a symbol
+table.
+
The following block-related functions are available in the @code{gdb}
module:
@code{False} if not. A block object can become invalid if the block it
refers to doesn't exist anymore in the inferior. All other
@code{gdb.Block} methods will throw an exception if it is invalid at
-the time the method is called. This method is also made available to
-the Python iterator object that @code{gdb.Block} provides in an iteration
-context and via the Python @code{iter} built-in function.
+the time the method is called. The block's validity is also checked
+during iteration over symbols of the block.
@end defun
@end table
Python}. This attribute is not writable.
@end defvar
+@defvar Symbol.line
+The line number in the source code at which the symbol was defined.
+This is an integer.
+@end defvar
+
@defvar Symbol.name
The name of the symbol as a string. This attribute is not writable.
@end defvar
@code{gdb} module and described later in this chapter.
@end defvar
+@defvar Symbol.needs_frame
+This is @code{True} if evaluating this symbol's value requires a frame
+(@pxref{Frames In Python}) and @code{False} otherwise. Typically,
+local variables will require a frame, but other symbols will not.
+@end defvar
+
@defvar Symbol.is_argument
@code{True} if the symbol is an argument of a function.
@end defvar
All other @code{gdb.Symbol} methods will throw an exception if it is
invalid at the time the method is called.
@end defun
+
+@defun Symbol.value (@r{[}frame@r{]})
+Compute the value of the symbol, as a @code{gdb.Value}. For
+functions, this computes the address of the function, cast to the
+appropriate type. If the symbol requires a frame in order to compute
+its value, then @var{frame} must be given. If @var{frame} is not
+given, or if @var{frame} is invalid, then this method will throw an
+exception.
+@end defun
@end table
The available domain categories in @code{gdb.Symbol} are represented
@defun Symtab.fullname ()
Return the symbol table's source absolute file name.
@end defun
+
+@defun Symtab.global_block ()
+Return the global block of the underlying symbol table.
+@xref{Blocks In Python}.
+@end defun
+
+@defun Symtab.static_block ()
+Return the static block of the underlying symbol table.
+@xref{Blocks In Python}.
+@end defun
@end table
@node Breakpoints In Python
attribute is @code{None}. This attribute is not writable.
@end defvar
+@node Finish Breakpoints in Python
+@subsubsection Finish Breakpoints
+
+@cindex python finish breakpoints
+@tindex gdb.FinishBreakpoint
+
+A finish breakpoint is a temporary breakpoint set at the return address of
+a frame, based on the @code{finish} command. @code{gdb.FinishBreakpoint}
+extends @code{gdb.Breakpoint}. The underlying breakpoint will be disabled
+and deleted when the execution will run out of the breakpoint scope (i.e.@:
+@code{Breakpoint.stop} or @code{FinishBreakpoint.out_of_scope} triggered).
+Finish breakpoints are thread specific and must be create with the right
+thread selected.
+
+@defun FinishBreakpoint.__init__ (@r{[}frame@r{]} @r{[}, internal@r{]})
+Create a finish breakpoint at the return address of the @code{gdb.Frame}
+object @var{frame}. If @var{frame} is not provided, this defaults to the
+newest frame. The optional @var{internal} argument allows the breakpoint to
+become invisible to the user. @xref{Breakpoints In Python}, for further
+details about this argument.
+@end defun
+
+@defun FinishBreakpoint.out_of_scope (self)
+In some circumstances (e.g.@: @code{longjmp}, C@t{++} exceptions, @value{GDBN}
+@code{return} command, @dots{}), a function may not properly terminate, and
+thus never hit the finish breakpoint. When @value{GDBN} notices such a
+situation, the @code{out_of_scope} callback will be triggered.
+
+You may want to sub-class @code{gdb.FinishBreakpoint} and override this
+method:
+
+@smallexample
+class MyFinishBreakpoint (gdb.FinishBreakpoint)
+ def stop (self):
+ print "normal finish"
+ return True
+
+ def out_of_scope ():
+ print "abnormal finish"
+@end smallexample
+@end defun
+
+@defvar FinishBreakpoint.return_value
+When @value{GDBN} is stopped at a finish breakpoint and the frame
+used to build the @code{gdb.FinishBreakpoint} object had debug symbols, this
+attribute will contain a @code{gdb.Value} object corresponding to the return
+value of the function. The value will be @code{None} if the function return
+type is @code{void} or if the return value was not computable. This attribute
+is not writable.
+@end defvar
+
@node Lazy Strings In Python
@subsubsection Python representation of lazy strings.
writable.
@end defvar
-@node Auto-loading
-@subsection Auto-loading
-@cindex auto-loading, Python
+@node Python Auto-loading
+@subsection Python Auto-loading
+@cindex Python auto-loading
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
+@file{@var{objfile}-gdb.py} (@pxref{objfile-gdb.py file})
+and @code{.debug_gdb_scripts} section
+(@pxref{dotdebug_gdb_scripts section}).
The auto-loading feature is useful for supplying application-specific
debugging commands and scripts.
and the list of auto-loaded scripts can be printed.
@table @code
-@kindex set auto-load-scripts
-@item set auto-load-scripts [yes|no]
+@anchor{set auto-load python-scripts}
+@kindex set auto-load python-scripts
+@item set auto-load python-scripts [on|off]
Enable or disable the auto-loading of Python scripts.
-@kindex show auto-load-scripts
-@item show auto-load-scripts
+@anchor{show auto-load python-scripts}
+@kindex show auto-load python-scripts
+@item show auto-load python-scripts
Show whether auto-loading of Python scripts is enabled or disabled.
-@kindex info auto-load-scripts
-@cindex print list of auto-loaded scripts
-@item info auto-load-scripts [@var{regexp}]
-Print the list of all scripts that @value{GDBN} auto-loaded.
+@anchor{info auto-load python-scripts}
+@kindex info auto-load python-scripts
+@cindex print list of auto-loaded Python scripts
+@item info auto-load python-scripts [@var{regexp}]
+Print the list of all Python scripts that @value{GDBN} auto-loaded.
-Also printed is the list of scripts that were mentioned in
+Also printed is the list of Python scripts that were mentioned in
the @code{.debug_gdb_scripts} section and were not found
-(@pxref{.debug_gdb_scripts section}).
+(@pxref{dotdebug_gdb_scripts section}).
This is useful because their names are not printed when @value{GDBN}
tries to load them and fails. There may be many of them, and printing
an error message for each one is problematic.
-If @var{regexp} is supplied only scripts with matching names are printed.
+If @var{regexp} is supplied only Python scripts with matching names are printed.
Example:
@smallexample
-(gdb) info auto-load-scripts
-Loaded Script
-Yes py-section-script.py
- full name: /tmp/py-section-script.py
-Missing my-foo-pretty-printers.py
+(gdb) info auto-load python-scripts
+Loaded Script
+Yes py-section-script.py
+ full name: /tmp/py-section-script.py
+No my-foo-pretty-printers.py
@end smallexample
@end table
function (@pxref{Objfiles In Python}). This can be useful for
registering objfile-specific pretty-printers.
+@menu
+* objfile-gdb.py file:: The @file{@var{objfile}-gdb.py} file
+* dotdebug_gdb_scripts section:: The @code{.debug_gdb_scripts} section
+* Which flavor to choose?::
+@end menu
+
@node objfile-gdb.py file
@subsubsection The @file{@var{objfile}-gdb.py} file
@cindex @file{@var{objfile}-gdb.py}
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
+a file named @file{@var{data-directory}/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.
So your @file{-gdb.py} file should be careful to avoid errors if it
is evaluated more than once.
-@node .debug_gdb_scripts section
+@node dotdebug_gdb_scripts section
@subsubsection The @code{.debug_gdb_scripts} section
@cindex @code{.debug_gdb_scripts} section
regular expressions.
@xref{Writing a Pretty-Printer}, for an example.
+@item FlagEnumerationPrinter (@var{name})
+A pretty-printer which handles printing of @code{enum} values. Unlike
+@value{GDBN}'s built-in @code{enum} printing, this printer attempts to
+work properly when there is some overlap between the enumeration
+constants. @var{name} is the name of the printer and also the name of
+the @code{enum} type to look up.
+
@item register_pretty_printer (@var{obj}, @var{printer}, @var{replace}=False)
Register @var{printer} with the pretty-printer list of @var{obj}.
If @var{replace} is @code{True} then any existing copy of the printer
on platforms where a suitable version of the @code{curses} library
is available.
-@pindex @value{GDBTUI}
The TUI mode is enabled by default when you invoke @value{GDBN} as
-either @samp{@value{GDBTUI}} or @samp{@value{GDBP} -tui}.
+@samp{@value{GDBP} -tui}.
You can also switch in and out of TUI mode while @value{GDBN} runs by
using various TUI commands and key bindings, such as @kbd{C-x C-a}.
@xref{TUI Keys, ,TUI Key Bindings}.
The inferior exited normally.
@item signal-received
A signal was received by the inferior.
+@item solib-event
+The inferior has stopped due to a library being loaded or unloaded.
+This can happen when @code{stop-on-solib-events} (@pxref{Files}) is
+set or when a @code{catch load} or @code{catch unload} catchpoint is
+in use (@pxref{Set Catchpoints}).
+@item fork
+The inferior has forked. This is reported when @code{catch fork}
+(@pxref{Set Catchpoints}) has been used.
+@item vfork
+The inferior has vforked. This is reported in when @code{catch vfork}
+(@pxref{Set Catchpoints}) has been used.
+@item syscall-entry
+The inferior entered a system call. This is reported when @code{catch
+syscall} (@pxref{Set Catchpoints}) has been used.
+@item syscall-entry
+The inferior returned from a system call. This is reported when
+@code{catch syscall} (@pxref{Set Catchpoints}) has been used.
+@item exec
+The inferior called @code{exec}. This is reported when @code{catch exec}
+(@pxref{Set Catchpoints}) has been used.
@end table
The @var{id} field identifies the thread that directly caused the stop
@item type
The varobj's type. This is a string representation of the type, as
-would be printed by the @value{GDBN} CLI.
+would be printed by the @value{GDBN} CLI. If @samp{print object}
+(@pxref{Print Settings, set print object}) is set to @code{on}, the
+@emph{actual} (derived) type of the object is shown rather than the
+@emph{declared} one.
@item thread-id
If a variable object is bound to a specific thread, then this is the
0.
@item type
-The type of the child.
+The type of the child. If @samp{print object}
+(@pxref{Print Settings, set print object}) is set to @code{on}, the
+@emph{actual} (derived) type of the object is shown rather than the
+@emph{declared} one.
@item value
If values were requested, this is the value.
changed, then this will be the string @samp{true}; otherwise it will
be @samp{false}.
+When a varobj's type changes, its children are also likely to have
+become incorrect. Therefore, the varobj's children are automatically
+deleted when this attribute is @samp{true}. Also, the varobj's update
+range, when set using the @code{-var-set-update-range} command, is
+unset.
+
@item new_type
If the varobj's type changed, then this field will be present and will
hold the new type.
* Declarations:: Relevant C struct declarations
* Registering Code:: Steps to register code
* Unregistering Code:: Steps to unregister code
+* Custom Debug Info:: Emit debug information in a custom format
@end menu
@node Declarations
If the JIT frees or recompiles code without unregistering it, then @value{GDBN}
and the JIT will leak the memory used for the associated symbol files.
+@node Custom Debug Info
+@section Custom Debug Info
+@cindex custom JIT debug info
+@cindex JIT debug info reader
+
+Generating debug information in platform-native file formats (like ELF
+or COFF) may be an overkill for JIT compilers; especially if all the
+debug info is used for is displaying a meaningful backtrace. The
+issue can be resolved by having the JIT writers decide on a debug info
+format and also provide a reader that parses the debug info generated
+by the JIT compiler. This section gives a brief overview on writing
+such a parser. More specific details can be found in the source file
+@file{gdb/jit-reader.in}, which is also installed as a header at
+@file{@var{includedir}/gdb/jit-reader.h} for easy inclusion.
+
+The reader is implemented as a shared object (so this functionality is
+not available on platforms which don't allow loading shared objects at
+runtime). Two @value{GDBN} commands, @code{jit-reader-load} and
+@code{jit-reader-unload} are provided, to be used to load and unload
+the readers from a preconfigured directory. Once loaded, the shared
+object is used the parse the debug information emitted by the JIT
+compiler.
+
+@menu
+* Using JIT Debug Info Readers:: How to use supplied readers correctly
+* Writing JIT Debug Info Readers:: Creating a debug-info reader
+@end menu
+
+@node Using JIT Debug Info Readers
+@subsection Using JIT Debug Info Readers
+@kindex jit-reader-load
+@kindex jit-reader-unload
+
+Readers can be loaded and unloaded using the @code{jit-reader-load}
+and @code{jit-reader-unload} commands.
+
+@table @code
+@item jit-reader-load @var{reader-name}
+Load the JIT reader named @var{reader-name}. On a UNIX system, this
+will usually load @file{@var{libdir}/gdb/@var{reader-name}}, where
+@var{libdir} is the system library directory, usually
+@file{/usr/local/lib}. Only one reader can be active at a time;
+trying to load a second reader when one is already loaded will result
+in @value{GDBN} reporting an error. A new JIT reader can be loaded by
+first unloading the current one using @code{jit-reader-load} and then
+invoking @code{jit-reader-load}.
+
+@item jit-reader-unload
+Unload the currently loaded JIT reader.
+
+@end table
+
+@node Writing JIT Debug Info Readers
+@subsection Writing JIT Debug Info Readers
+@cindex writing JIT debug info readers
+
+As mentioned, a reader is essentially a shared object conforming to a
+certain ABI. This ABI is described in @file{jit-reader.h}.
+
+@file{jit-reader.h} defines the structures, macros and functions
+required to write a reader. It is installed (along with
+@value{GDBN}), in @file{@var{includedir}/gdb} where @var{includedir} is
+the system include directory.
+
+Readers need to be released under a GPL compatible license. A reader
+can be declared as released under such a license by placing the macro
+@code{GDB_DECLARE_GPL_COMPATIBLE_READER} in a source file.
+
+The entry point for readers is the symbol @code{gdb_init_reader},
+which is expected to be a function with the prototype
+
+@findex gdb_init_reader
+@smallexample
+extern struct gdb_reader_funcs *gdb_init_reader (void);
+@end smallexample
+
+@cindex @code{struct gdb_reader_funcs}
+
+@code{struct gdb_reader_funcs} contains a set of pointers to callback
+functions. These functions are executed to read the debug info
+generated by the JIT compiler (@code{read}), to unwind stack frames
+(@code{unwind}) and to create canonical frame IDs
+(@code{get_Frame_id}). It also has a callback that is called when the
+reader is being unloaded (@code{destroy}). The struct looks like this
+
+@smallexample
+struct gdb_reader_funcs
+@{
+ /* Must be set to GDB_READER_INTERFACE_VERSION. */
+ int reader_version;
+
+ /* For use by the reader. */
+ void *priv_data;
+
+ gdb_read_debug_info *read;
+ gdb_unwind_frame *unwind;
+ gdb_get_frame_id *get_frame_id;
+ gdb_destroy_reader *destroy;
+@};
+@end smallexample
+
+@cindex @code{struct gdb_symbol_callbacks}
+@cindex @code{struct gdb_unwind_callbacks}
+
+The callbacks are provided with another set of callbacks by
+@value{GDBN} to do their job. For @code{read}, these callbacks are
+passed in a @code{struct gdb_symbol_callbacks} and for @code{unwind}
+and @code{get_frame_id}, in a @code{struct gdb_unwind_callbacks}.
+@code{struct gdb_symbol_callbacks} has callbacks to create new object
+files and new symbol tables inside those object files. @code{struct
+gdb_unwind_callbacks} has callbacks to read registers off the current
+frame and to write out the values of the registers in the previous
+frame. Both have a callback (@code{target_read}) to read bytes off the
+target's address space.
+
+@node In-Process Agent
+@chapter In-Process Agent
+@cindex debugging agent
+The traditional debugging model is conceptually low-speed, but works fine,
+because most bugs can be reproduced in debugging-mode execution. However,
+as multi-core or many-core processors are becoming mainstream, and
+multi-threaded programs become more and more popular, there should be more
+and more bugs that only manifest themselves at normal-mode execution, for
+example, thread races, because debugger's interference with the program's
+timing may conceal the bugs. On the other hand, in some applications,
+it is not feasible for the debugger to interrupt the program's execution
+long enough for the developer to learn anything helpful about its behavior.
+If the program's correctness depends on its real-time behavior, delays
+introduced by a debugger might cause the program to fail, even when the
+code itself is correct. It is useful to be able to observe the program's
+behavior without interrupting it.
+
+Therefore, traditional debugging model is too intrusive to reproduce
+some bugs. In order to reduce the interference with the program, we can
+reduce the number of operations performed by debugger. The
+@dfn{In-Process Agent}, a shared library, is running within the same
+process with inferior, and is able to perform some debugging operations
+itself. As a result, debugger is only involved when necessary, and
+performance of debugging can be improved accordingly. Note that
+interference with program can be reduced but can't be removed completely,
+because the in-process agent will still stop or slow down the program.
+
+The in-process agent can interpret and execute Agent Expressions
+(@pxref{Agent Expressions}) during performing debugging operations. The
+agent expressions can be used for different purposes, such as collecting
+data in tracepoints, and condition evaluation in breakpoints.
+
+@anchor{Control Agent}
+You can control whether the in-process agent is used as an aid for
+debugging with the following commands:
+
+@table @code
+@kindex set agent on
+@item set agent on
+Causes the in-process agent to perform some operations on behalf of the
+debugger. Just which operations requested by the user will be done
+by the in-process agent depends on the its capabilities. For example,
+if you request to evaluate breakpoint conditions in the in-process agent,
+and the in-process agent has such capability as well, then breakpoint
+conditions will be evaluated in the in-process agent.
+
+@kindex set agent off
+@item set agent off
+Disables execution of debugging operations by the in-process agent. All
+of the operations will be performed by @value{GDBN}.
+
+@kindex show agent
+@item show agent
+Display the current setting of execution of debugging operations by
+the in-process agent.
+@end table
+
@node GDB Bugs
@chapter Reporting Bugs in @value{GDBN}
@cindex bugs in @value{GDBN}
@item
Target descriptions (@pxref{Target Descriptions})
@item
-Remote shared library lists (@pxref{Library List Format})
+Remote shared library lists (@xref{Library List Format},
+or alternatively @pxref{Library List Format for SVR4 Targets})
@item
MS-Windows shared libraries (@pxref{Shared Libraries})
@item
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}.
+@xref{dotdebug_gdb_scripts section}.
@kindex maint print statistics
@cindex bcache statistics
* Examples::
* File-I/O Remote Protocol Extension::
* Library List Format::
+* Library List Format for SVR4 Targets::
* Memory Map Format::
* Thread List Format::
* Traceframe Info Format::
signal @samp{0}, regardless of whether the target uses some other signal
as an implementation detail.
+The stub must support @samp{vCont} if it reports support for
+multiprocess extensions (@pxref{multiprocess extensions}). Note that in
+this case @samp{vCont} actions can be specified to apply to all threads
+in a process by using the @samp{p@var{pid}.-1} form of the
+@var{thread-id}.
+
Reply:
@xref{Stop Reply Packets}, for the reply specifications.
stub is allowed to delay erase operation until the @samp{vFlashDone}
packet is received.
-The stub must support @samp{vCont} if it reports support for
-multiprocess extensions (@pxref{multiprocess extensions}). Note that in
-this case @samp{vCont} actions can be specified to apply to all threads
-in a process by using the @samp{p@var{pid}.-1} form of the
-@var{thread-id}.
-
Reply:
@table @samp
@item OK
be implemented in an idempotent way.}
@item z0,@var{addr},@var{kind}
-@itemx Z0,@var{addr},@var{kind}
+@itemx Z0,@var{addr},@var{kind}@r{[};@var{cond_list}@dots{}@r{]}
@cindex @samp{z0} packet
@cindex @samp{Z0} packet
Insert (@samp{Z0}) or remove (@samp{z0}) a memory breakpoint at address
the breakpoint in bytes that should be inserted. E.g., the @sc{arm}
and @sc{mips} can insert either a 2 or 4 byte breakpoint. Some
architectures have additional meanings for @var{kind};
+@var{cond_list} is an optional list of conditional expressions in bytecode
+form that should be evaluated on the target's side. These are the
+conditions that should be taken into consideration when deciding if
+the breakpoint trigger should be reported back to @var{GDBN}.
+
+The @var{cond_list} parameter is comprised of a series of expressions,
+concatenated without separators. Each expression has the following form:
+
+@table @samp
+
+@item X @var{len},@var{expr}
+@var{len} is the length of the bytecode expression and @var{expr} is the
+actual conditional expression in bytecode form.
+
+@end table
+
see @ref{Architecture-Specific Protocol Details}.
@emph{Implementation note: It is possible for a target to copy or move
@end table
@item z1,@var{addr},@var{kind}
-@itemx Z1,@var{addr},@var{kind}
+@itemx Z1,@var{addr},@var{kind}@r{[};@var{cond_list}@dots{}@r{]}
@cindex @samp{z1} packet
@cindex @samp{Z1} packet
Insert (@samp{Z1}) or remove (@samp{z1}) a hardware breakpoint at
A hardware breakpoint is implemented using a mechanism that is not
dependant on being able to modify the target's memory. @var{kind}
-has the same meaning as in @samp{Z0} packets.
+and @var{cond_list} have the same meaning as in @samp{Z0} packets.
@emph{Implementation note: A hardware breakpoint is not affected by code
movement.}
@table @samp
+@item QAgent:1
+@item QAgent:0
+Turn on or off the agent as a helper to perform some debugging operations
+delegated from @value{GDBN} (@pxref{Control Agent}).
+
@item QAllow:@var{op}:@var{val}@dots{}
@cindex @samp{QAllow} packet
Specify which operations @value{GDBN} expects to request of the
This packet is not probed by default; the remote stub must request it,
by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}).
+@item QProgramSignals: @var{signal} @r{[};@var{signal}@r{]}@dots{}
+@cindex signals the inferior may see, remote request
+@cindex @samp{QProgramSignals} packet
+@anchor{QProgramSignals}
+Each listed @var{signal} may be delivered to the inferior process.
+Others should be silently discarded.
+
+In some cases, the remote stub may need to decide whether to deliver a
+signal to the program or not without @value{GDBN} involvement. One
+example of that is while detaching --- the program's threads may have
+stopped for signals that haven't yet had a chance of being reported to
+@value{GDBN}, and so the remote stub can use the signal list specified
+by this packet to know whether to deliver or ignore those pending
+signals.
+
+This does not influence whether to deliver a signal as requested by a
+resumption packet (@pxref{vCont packet}).
+
+Signals are numbered identically to continue packets and stop replies
+(@pxref{Stop Reply Packets}). Each @var{signal} list item should be
+strictly greater than the previous item. Multiple
+@samp{QProgramSignals} packets do not combine; any earlier
+@samp{QProgramSignals} list is completely replaced by the new list.
+
+Reply:
+@table @samp
+@item OK
+The request succeeded.
+
+@item E @var{nn}
+An error occurred. @var{nn} are hex digits.
+
+@item
+An empty reply indicates that @samp{QProgramSignals} is not supported
+by the stub.
+@end table
+
+Use of this packet is controlled by the @code{set remote program-signals}
+command (@pxref{Remote Configuration, set remote program-signals}).
+This packet is not probed by default; the remote stub must request it,
+by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}).
+
@item qRcmd,@var{command}
@cindex execute remote command, remote request
@cindex @samp{qRcmd} packet
@tab @samp{-}
@tab Yes
+@item @samp{qXfer:uib:read}
+@tab No
+@tab @samp{-}
+@tab Yes
+
@item @samp{qXfer:fdpic:read}
@tab No
@tab @samp{-}
@tab @samp{-}
@tab No
+@item @samp{ConditionalBreakpoints}
+@tab No
+@tab @samp{-}
+@tab No
+
@item @samp{ConditionalTracepoints}
@tab No
@tab @samp{-}
@tab @samp{-}
@tab No
+@item @samp{QAgent}
+@tab No
+@tab @samp{-}
+@tab No
+
@item @samp{QAllow}
@tab No
@tab @samp{-}
The remote stub understands the @samp{qXfer:libraries:read} packet
(@pxref{qXfer library list read}).
+@item qXfer:libraries-svr4:read
+The remote stub understands the @samp{qXfer:libraries-svr4:read} packet
+(@pxref{qXfer svr4 library list read}).
+
@item qXfer:memory-map:read
The remote stub understands the @samp{qXfer:memory-map:read} packet
(@pxref{qXfer memory map read}).
The remote stub understands the @samp{qXfer:traceframe-info:read}
packet (@pxref{qXfer traceframe info read}).
+@item qXfer:uib:read
+The remote stub understands the @samp{qXfer:uib:read}
+packet (@pxref{qXfer unwind info block}).
+
@item qXfer:fdpic:read
The remote stub understands the @samp{qXfer:fdpic:read}
packet (@pxref{qXfer fdpic loadmap read}).
The remote stub understands the @samp{qXfer:osdata:read} packet
((@pxref{qXfer osdata read}).
+@item ConditionalBreakpoints
+The target accepts and implements evaluation of conditional expressions
+defined for breakpoints. The target will only report breakpoint triggers
+when such conditions are true (@pxref{Conditions, ,Break Conditions}).
+
@item ConditionalTracepoints
The remote stub accepts and implements conditional expressions defined
for tracepoints (@pxref{Tracepoint Conditions}).
The remote stub understands the @samp{QTDPsrc} packet that supplies
the source form of tracepoint definitions.
+@item QAgent
+The remote stub understands the @samp{QAgent} packet.
+
@item QAllow
The remote stub understands the @samp{QAllow} packet.
@cindex static tracepoints, in remote protocol
The remote stub supports static tracepoints.
+@item InstallInTrace
+@anchor{install tracepoint in tracing}
+The remote stub supports installing tracepoint in tracing.
+
@item EnableDisableTracepoints
The remote stub supports the @samp{QTEnable} (@pxref{QTEnable}) and
@samp{QTDisable} (@pxref{QTDisable}) packets that allow tracepoints
@itemx qTfP
@itemx qTfV
@itemx QTFrame
+@itemx qTMinFTPILen
+
@xref{Tracepoint Packets}.
@item qThreadExtraInfo,@var{thread-id}
conventions above. Please don't use this packet as a model for new
packets.)
+@item QTNotes
+@item qTP
@item QTSave
@item qTsP
@item qTsV
This packet is not probed by default; the remote stub must request it,
by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}).
+@item qXfer:libraries-svr4:read:@var{annex}:@var{offset},@var{length}
+@anchor{qXfer svr4 library list read}
+Access the target's list of loaded libraries when the target is an SVR4
+platform. @xref{Library List Format for SVR4 Targets}. The annex part
+of the generic @samp{qXfer} packet must be empty (@pxref{qXfer read}).
+
+This packet is optional for better performance on SVR4 targets.
+@value{GDBN} uses memory read packets to read the SVR4 library list otherwise.
+
+This packet is not probed by default; the remote stub must request it,
+by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}).
+
@item qXfer:memory-map:read::@var{offset},@var{length}
@anchor{qXfer memory map read}
Access the target's @dfn{memory-map}. @xref{Memory Map Format}. The
This packet is not probed by default; the remote stub must request it,
by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}).
+@item qXfer:uib:read:@var{pc}:@var{offset},@var{length}
+@anchor{qXfer unwind info block}
+
+Return the unwind information block for @var{pc}. This packet is used
+on OpenVMS/ia64 to ask the kernel unwind information.
+
+This packet is not probed by default.
+
@item qXfer:fdpic:read:@var{annex}:@var{offset},@var{length}
@anchor{qXfer fdpic loadmap read}
Read contents of @code{loadmap}s on the target system. The
Like @samp{QTFrame:range:@var{start}:@var{end}}, but select the first
frame @emph{outside} the given range of addresses (exclusive).
+@item qTMinFTPILen
+This packet requests the minimum length of instruction at which a fast
+tracepoint (@pxref{Set Tracepoints}) may be placed. For instance, on
+the 32-bit x86 architecture, it is possible to use a 4-byte jump, but
+it depends on the target system being able to create trampolines in
+the first 64K of memory, which might or might not be possible for that
+system. So the reply to this packet will be 4 if it is able to
+arrange for that.
+
+Replies:
+
+@table @samp
+@item 0
+The minimum instruction length is currently unknown.
+@item @var{length}
+The minimum instruction length is @var{length}, where @var{length} is greater
+or equal to 1. @var{length} is a hexadecimal number. A reply of 1 means
+that a fast tracepoint may be placed on any instruction regardless of size.
+@item E
+An error has occurred.
+@item
+An empty reply indicates that the request is not supported by the stub.
+@end table
+
@item QTStart
Begin the tracepoint experiment. Begin collecting data from
tracepoint hits in the trace frame buffer. This packet supports the
@item tnotrun:0
No trace has been run yet.
-@item tstop:0
-The trace was stopped by a user-originated stop command.
+@item tstop[:@var{text}]:0
+The trace was stopped by a user-originated stop command. The optional
+@var{text} field is a user-supplied string supplied as part of the
+stop command (for instance, an explanation of why the trace was
+stopped manually). It is hex-encoded.
@item tfull:0
The trace stopped because the trace buffer filled up.
@end table
+@item qTP:@var{tp}:@var{addr}
+@cindex tracepoint status, remote request
+@cindex @samp{qTP} packet
+Ask the stub for the current state of tracepoint number @var{tp} at
+address @var{addr}.
+
+Replies:
+@table @samp
+@item V@var{hits}:@var{usage}
+The tracepoint has been hit @var{hits} times so far during the trace
+run, and accounts for @var{usage} in the trace buffer. Note that
+@code{while-stepping} steps are not counted as separate hits, but the
+steps' space consumption is added into the usage number.
+
+@end table
+
@item qTV:@var{var}
@cindex trace state variable value, remote request
@cindex @samp{qTV} packet
This packet directs the target to use a circular trace buffer if
@var{value} is 1, or a linear buffer if the value is 0.
+@item QTNotes:@r{[}@var{type}:@var{text}@r{]}@r{[};@var{type}:@var{text}@r{]}@dots{}
+This packet adds optional textual notes to the trace run. Allowable
+types include @code{user}, @code{notes}, and @code{tstop}, the
+@var{text} fields are arbitrary strings, hex-encoded.
+
@end table
@subsection Relocate instruction reply packet
Delete the file at @var{pathname} on the target. Return 0,
or -1 if an error occurs. @var{pathname} is a string.
+@item vFile:readlink: @var{filename}
+Read value of symbolic link @var{filename} on the target. Return
+the number of bytes read, or -1 if an error occurs.
+
+The data read should be returned as a binary attachment on success.
+If zero bytes were read, the response should include an empty binary
+attachment (i.e.@: a trailing semicolon). The return value is the
+number of target bytes read; the binary attachment may be longer if
+some characters were escaped.
+
@end table
@node Interrupts
single library element, and you must supply at least one segment or
section for each library.
+@node Library List Format for SVR4 Targets
+@section Library List Format for SVR4 Targets
+@cindex library list format, remote protocol
+
+On SVR4 platforms @value{GDBN} can use the symbol table of a dynamic loader
+(e.g.@: @file{ld.so}) and normal memory operations to maintain a list of
+shared libraries. Still a special library list provided by this packet is
+more efficient for the @value{GDBN} remote protocol.
+
+The @samp{qXfer:libraries-svr4:read} packet returns an XML document which lists
+loaded libraries and their SVR4 linker parameters. For each library on SVR4
+target, the following parameters are reported:
+
+@itemize @minus
+@item
+@code{name}, the absolute file name from the @code{l_name} field of
+@code{struct link_map}.
+@item
+@code{lm} with address of @code{struct link_map} used for TLS
+(Thread Local Storage) access.
+@item
+@code{l_addr}, the displacement as read from the field @code{l_addr} of
+@code{struct link_map}. For prelinked libraries this is not an absolute
+memory address. It is a displacement of absolute memory address against
+address the file was prelinked to during the library load.
+@item
+@code{l_ld}, which is memory address of the @code{PT_DYNAMIC} segment
+@end itemize
+
+Additionally the single @code{main-lm} attribute specifies address of
+@code{struct link_map} used for the main executable. This parameter is used
+for TLS access and its presence is optional.
+
+@value{GDBN} must be linked with the Expat library to support XML
+SVR4 library lists. @xref{Expat}.
+
+A simple memory map, with two loaded libraries (which do not use prelink),
+looks like this:
+
+@smallexample
+<library-list-svr4 version="1.0" main-lm="0xe4f8f8">
+ <library name="/lib/ld-linux.so.2" lm="0xe4f51c" l_addr="0xe2d000"
+ l_ld="0xe4eefc"/>
+ <library name="/lib/libc.so.6" lm="0xe4fbe8" l_addr="0x154000"
+ l_ld="0x152350"/>
+</library-list-svr>
+@end smallexample
+
+The format of an SVR4 library list is described by this DTD:
+
+@smallexample
+<!-- library-list-svr4: Root element with versioning -->
+<!ELEMENT library-list-svr4 (library)*>
+<!ATTLIST library-list-svr4 version CDATA #FIXED "1.0">
+<!ATTLIST library-list-svr4 main-lm CDATA #IMPLIED>
+<!ELEMENT library EMPTY>
+<!ATTLIST library name CDATA #REQUIRED>
+<!ATTLIST library lm CDATA #REQUIRED>
+<!ATTLIST library l_addr CDATA #REQUIRED>
+<!ATTLIST library l_ld CDATA #REQUIRED>
+@end smallexample
+
@node Memory Map Format
@section Memory Map Format
@cindex memory map format
contain registers @samp{f0} through @samp{f31}, @samp{fcsr}, and
@samp{fir}. They may be 32-bit or 64-bit depending on the target.
+The @samp{org.gnu.gdb.mips.dsp} feature is optional. It should
+contain registers @samp{hi1} through @samp{hi3}, @samp{lo1} through
+@samp{lo3}, and @samp{dspctl}. The @samp{dspctl} register should
+be 32-bit and the rest may be 32-bit or 64-bit depending on the target.
+
The @samp{org.gnu.gdb.mips.linux} feature is optional. It should
contain a single register, @samp{restart}, which is used by the
Linux kernel to control restartable syscalls.
@enumerate
@item
-The version number, currently 5. Versions 1, 2 and 3 are obsolete.
-Version 4 differs by its hashing function.
+The version number, currently 6. Versions 1, 2 and 3 are obsolete.
+Version 4 uses a different hashing function from versions 5 and 6.
+Version 6 includes symbols for inlined functions, whereas versions
+4 and 5 do not. @value{GDBN} will only read version 4 and 5 indices
+if the @code{--use-deprecated-index-sections} option is used.
@item
The offset, from the start of the file, of the CU list.
@item Version 4
The formula is @code{r = r * 67 + c - 113}.
-@item Version 5
+@item Versions 5 and 6
The formula is @code{r = r * 67 + tolower (c) - 113}.
@end table
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