Commit 0df6175c authored by Chong Yidong's avatar Chong Yidong

* doc/emacs/building.texi: Re-apply 2009-12-29T07:15:34Z!nickrob@snap.net.nz, which was

accidentally overwritten in the last change.
parent ac4a9529
......@@ -857,12 +857,11 @@ multiple programs within one Emacs session.
* Source Buffers:: Use the mouse in the fringe/margin to
control your program.
* Breakpoints Buffer:: A breakpoint control panel.
* Threads Buffer:: Displays your threads.
* Stack Buffer:: Select a frame from the call stack.
* Other GDB-UI Buffers:: Input/output, locals, registers,
assembler, threads and memory buffers.
* Watch Expressions:: Monitor variable values in the speedbar.
* Multithreaded Debugging:: Debugging programs with several threads.
* Reverse Debugging:: Execute and reverse debug your program.
@end menu
@node GDB-UI Layout
......@@ -887,7 +886,7 @@ displays the following frame layout:
|--------------------------------+--------------------------------+
| Primary Source buffer | I/O buffer for debugged pgm |
|--------------------------------+--------------------------------+
| Stack buffer | Breakpoints/Thread buffer |
| Stack buffer | Breakpoints/Threads buffer |
+--------------------------------+--------------------------------+
@end group
@end smallexample
......@@ -1015,92 +1014,10 @@ Visit the source line for the current breakpoint
Visit the source line for the breakpoint you click on.
@end table
@vindex gdb-show-threads-by-default
When @code{gdb-many-windows} is non-@code{nil}, the breakpoints buffer
shares its window with the threads buffer. To switch from one to the
other click with @kbd{Mouse-1} on the relevant button in the header
line, or press @kbd{TAB} inside that buffer. If
@code{gdb-show-threads-by-default} is non-@code{nil}, the threads
buffer, rather than the breakpoints buffer, is shown at start up.
@node Threads Buffer
@subsubsection Threads Buffer
@findex gdb-select-thread
The threads buffer displays a summary of all threads currently in your
program (@pxref{Threads, Threads, Debugging programs with multiple
threads, gdb, The GNU debugger}). Move point to any thread in the list
and press @key{RET} to select it (@code{gdb-select-thread}) and
display the associated source in the primary source buffer.
Alternatively, click @kbd{Mouse-2} on a thread to select it. Contents
of all GDB buffers are updated whenever you select a thread.
You can customize variables under @code{gdb-buffers} group to select
fields included in threads buffer.
@table @code
@item gdb-thread-buffer-verbose-names
@vindex gdb-thread-buffer-verbose-names
Show long thread names like @samp{Thread 0x4e2ab70 (LWP 1983)} in
threads buffer.
@item gdb-thread-buffer-arguments
@vindex gdb-thread-buffer-arguments
Show arguments of thread top frames in threads buffer.
@item gdb-thread-buffer-locations
@vindex gdb-thread-buffer-locations
Show file information or library names in threads buffer.
@item gdb-thread-buffer-addresses
@vindex gdb-thread-buffer-addresses
Show addresses for thread frames in threads buffer.
@end table
It’s possible to observe information for several threads
simultaneously (in addition to buffers which show information for
currently selected thread) using the following keys from the threads
buffer.
@table @kbd
@item d
@kindex d @r{(GDB threads buffer)}
@findex gdb-display-disassembly-for-thread
Display disassembly buffer for the thread at current line.
(@code{gdb-display-disassembly-for-thread})
@item f
@kindex f @r{(GDB threads buffer)}
@findex gdb-display-stack-for-thread
Display stack buffer for the thread at current line.
(@code{gdb-display-stack-for-thread}).
@item l
@kindex l @r{(GDB threads buffer)}
@findex gdb-display-locals-for-thread
Display locals buffer for the thread at current line.
(@code{gdb-display-locals-for-thread}).
@item r
@kindex r @r{(GDB threads buffer)}
@findex gdb-display-registers-for-thread
Display registers buffer for the thread at current line.
(@code{gdb-display-registers-for-thread}).
@end table
Pressing their upper-case counterparts, @kbd{D}, @kbd{F} ,@kbd{L} and
@kbd{R} displays the corresponding buffer in a new frame.
When you create a buffer showing information about some specific
thread, it becomes bound to that thread and keeps showing actual
information while you debug your program. Every GDB buffer contains a
number of thread it shows information for in its mode name. Thread
number is also included in the buffer name of bound buffers to prevent
buffer names clashing.
Further commands are available in the threads buffer which depend on the
mode of GDB that is used for controlling execution of your program.
(@pxref{Multithreaded Debugging, Stopping and Starting Multi-threaded Programs}).
line.
@node Stack Buffer
@subsubsection Stack Buffer
......@@ -1137,7 +1054,7 @@ as are the commands to send signals to the debugged program.
@item Locals Buffer
The locals buffer displays the values of local variables of the
current frame for simple data types (@pxref{Frame Info, Frame Info,
Information on a frame, gdb, The GNU debugger}). Press @key{RET} or
Information on a frame, gdb, The GNU debugger}). Press @key{RET} or
click @kbd{Mouse-2} on the value if you want to edit it.
Arrays and structures display their type only. With GDB 6.4 or later,
......@@ -1156,12 +1073,27 @@ With GDB 6.4 or later, recently changed register values display with
press @key{SPC} to toggle the display of floating point registers
(@code{toggle-gdb-all-registers}).
@item Disassembly Buffer
The disassembly buffer displays the current frame as machine code. An
@item Assembler Buffer
The assembler buffer displays the current frame as machine code. An
arrow points to the current instruction, and you can set and remove
breakpoints as in a source buffer. Breakpoint icons also appear in
the fringe or margin.
@item Threads Buffer
@findex gdb-threads-select
The threads buffer displays a summary of all threads currently in your
program (@pxref{Threads, Threads, Debugging programs with multiple
threads, gdb, The GNU debugger}). Move point to any thread in the
list and press @key{RET} to select it (@code{gdb-threads-select}) and
display the associated source in the primary source buffer.
Alternatively, click @kbd{Mouse-2} on a thread to select it. If the
locals buffer is visible, its contents update to display the variables
that are local in the new thread.
When there is more than one main thread and the threads buffer is
present, Emacs displays the selected thread number in the mode line of
many of the GDB-UI Buffers.
@item Memory Buffer
The memory buffer lets you examine sections of program memory
(@pxref{Memory, Memory, Examining memory, gdb, The GNU debugger}).
......@@ -1174,9 +1106,8 @@ size for these data items.
When @code{gdb-many-windows} is non-@code{nil}, the threads buffer
shares its window with the breakpoints buffer, and the locals buffer
with the registers buffer. To switch from one to the other click with
@kbd{Mouse-1} on the relevant button in the header line or press
@kbd{TAB} inside the buffer.
with the registers buffer. To switch from one to the other click with
@kbd{Mouse-1} on the relevant button in the header line.
@node Watch Expressions
@subsubsection Watch Expressions
......@@ -1244,96 +1175,26 @@ expressions updates, set @code{gdb-speedbar-auto-raise} to
non-@code{nil}. This can be useful if you are debugging with a full
screen Emacs frame.
@node Multithreaded Debugging
@subsubsection Stopping and Starting Multi-threaded Programs
@cindex Multithreaded debugging in GDB
@subsubheading All-stop Debugging
In all-stop mode, whenever your program stops, @emph{all} threads of
execution stop. Likewise, whenever you restart the program, all
threads start executing. @xref{All-Stop Mode, , All-Stop Mode, gdb,
The GNU debugger}. You can enable this behaviour in Emacs by setting
@code{gdb-non-stop-setting} to @code{nil} before starting a debugging
session.
@subsubheading Non-stop Debugging
@cindex Non-stop debugging in GDB
For some multi-threaded targets, GDB supports a further mode of
operation in which you can examine stopped program threads in the
debugger while other threads continue to execute freely.
@xref{Non-Stop Mode, , Non-Stop Mode, gdb, The GNU debugger}.
This is referred to as @dfn{non-stop} mode.
Versions of GDB prior to 7.0 do not support non-stop mode and it does
not work on all targets. In such cases, Emacs uses all-stop mode
regardless of the value of @code{gdb-non-stop-setting}.
@vindex gdb-non-stop-setting
If the variable @code{gdb-non-stop-setting} is non-@code{nil} (the
default value), Emacs tries to start GDB in non-stop mode. Note that
GDB debugging session needs to be restarted for change of this setting
to take effect.
@vindex gdb-switch-when-another-stopped
When a thread stops in non-stop mode, Emacs automatically switches to
that thread. It may be undesirable to allow switching of current
thread when some other stopped thread is already selected. Set
@code{gdb-switch-when-another-stopped} to @code{nil} to prevent this.
@vindex gdb-switch-reasons
Emacs can decide whether or not to switch to the stopped thread
depending on the reason which caused the stop. Customize
@code{gdb-switch-reasons} to select stop reasons which make Emacs
switch thread.
@vindex gdb-stopped-hooks
The variable @code{gdb-stopped-hooks} allows you to execute your
functions whenever some thread stops.
In non-stop mode, you can switch between different modes for GUD
execution control commands.
@vindex gdb-gud-control-all-threads
@table @dfn
@item Non-stop/A
When @code{gdb-gud-control-all-threads} is @code{t} (the default
value), interruption and continuation commands apply to all threads,
so you can halt or continue all your threads with one command using
@code{gud-stop-subjob} and @code{gud-cont}, respectively. The
@samp{Go} button is shown on the toolbar when at least one thread is
stopped, whereas @samp{Stop} button is shown when at least one thread
is running.
@item Non-stop/T
When @code{gdb-gud-control-all-threads} is @code{nil}, only the
current thread is stopped/continued. @samp{Go} and @samp{Stop}
buttons on the GUD toolbar are shown depending on the state of current
thread.
@end table
You can change the current value of @code{gdb-gud-control-all-threads}
from the tool bar or from @samp{GUD->GDB-MI} menu.
Stepping commands always apply to the current thread.
@subsubheading Fine Thread Control
In non-stop mode, you can interrupt/continue your threads without
selecting them. Hitting @kbd{i} in threads buffer interrupts thread
under point, @kbd{c} continues it, @kbd{s} steps through. More such
commands may be added in the future.
Combined with creating bound buffers for any thread, this allows you
to change and track state of many threads in the same time.
Note that when you interrupt a thread, it stops with @samp{signal
received} reason. If that reason is included in your
@code{gdb-switch-reasons} (it is by default), Emacs will switch to
that thread.
@node Reverse Debugging
@subsubsection Reverse Debugging
The GDB tool bar shares many buttons with the other GUD debuggers
for tasks like stepping and printing expressions. It also has a
further set of buttons that allow reverse debugging (@pxref{Process
Record and Replay, , ,gdb, The GNU debugger}). This is useful when it
takes a long time to reproduce the conditions where your program fails
or for transient problems, like race conditions in multi-threaded
programs, where a failure might otherwise be hard to reproduce.
To use reverse debugging, set a breakpoint slightly before the
location of interest and run your program to that point. Enable
process recording by clicking on the record button. At this point, a
new set of buttons appear. These buttons allow program execution in
the reverse direction. Run your program over the code where the
problem occurs, and then use the new set of buttons to retrace your
steps, examine values, and analyze the problem. When analysis is
complete, turn off process recording by clicking on the record button
again.
@node Executing Lisp
@section Executing Lisp Expressions
......
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