New commands `enable probe' and `disable probe'.

This patch adds the above-mentioned commands to the generic probe
abstraction implemented in probe.[ch].  The effects associated to
enabling or disabling a probe depend on the type of probe being
handled, and is triggered by invoking two back-end hooks in
`probe_ops'.

In case some particular probe type does not support the notion of
enabling and/or disabling, the corresponding fields on `probe_ops' can
be initialized to NULL.  This is the case of SystemTap probes.

gdb/ChangeLog:

2015-02-17  Jose E. Marchesi  <jose.marchesi@oracle.com>

	* stap-probe.c (stap_probe_ops): Add NULLs in the static
	stap_probe_ops for `enable_probe' and `disable_probe'.
	* probe.c (enable_probes_command): New function.
	(disable_probes_command): Likewise.
	(_initialize_probe): Define the cli commands `enable probe' and
	`disable probe'.
	(parse_probe_linespec): New function.
	(info_probes_for_ops): Use parse_probe_linespec.
	* probe.h (probe_ops): New hooks `enable_probe' and
	`disable_probe'.

gdb/doc/ChangeLog:

2015-02-17  Jose E. Marchesi  <jose.marchesi@oracle.com>

	* gdb.texinfo (Static Probe Points): Cover the `enable probe' and
	`disable probe' commands.

2 files changed, 34 insertions, 0 deletions

diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 62726ff..090442d 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,8 @@
+2015-02-17  Jose E. Marchesi  <jose.marchesi@oracle.com>
+
+	* gdb.texinfo (Static Probe Points): Cover the `enable probe' and
+	`disable probe' commands.
+
 2015-02-12  David Taylor  <dtaylor@emc.com>
 
 	* gdb.texinfo (Tracepoint Packets): Document the builtin and name
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index c4f03b2..b11c1bb 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -5011,6 +5011,35 @@ given, all object files are considered.
 List the available static probes, from all types.
 @end table
 
+@cindex enabling and disabling probes
+Some probe points can be enabled and/or disabled.  The effect of
+enabling or disabling a probe depends on the type of probe being
+handled.  @code{SystemTap} probes cannot be disabled.
+
+You can enable (or disable) one or more probes using the following
+commands, with optional arguments:
+
+@table @code
+@kindex enable probes
+@item enable probes @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 enable.  If omitted,
+all probes from all providers are enabled.
+
+If given, @var{name} is a regular expression to match against probe
+names when selecting which probes to enable.  If omitted, probe names
+are not considered when deciding whether to enable 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.
+
+@kindex disable probes
+@item disable probes @r{[}@var{provider} @r{[}@var{name} @r{[}@var{objfile}@r{]}@r{]}@r{]}
+See the @code{enable probes} command above for a description of the
+optional arguments accepted by this command.
+@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