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Only call {set,clear}_semaphore probe function if they are not NULL

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This patch is a response to what I commented on:

  <https://sourceware.org/ml/gdb-patches/2014-10/msg00046.html>

When reviewing Jose's USDT probe support patches.  Basically, in his
patch he had to create dummy functions for the set_semaphore and the
clear_semaphore methods of probe_ops (gdb/probe.h), because those
functions were called inconditionally from inside gdb/breakpoint.c and
gdb/tracepoint.c.  However, the semaphore concept may not apply to all
types of probes, and this is the case here: USDT probes do not have
semaphores (although SDT probes do).

Anyway, this is a simple (almost obvious) patch to guard the call to
{set,clear}_semaphore.  It does not introduce any regression on a
Fedora 20 x86_64.

I will apply it in a few days in case there is no comment.

gdb/ChangeLog:
2014-10-14  Sergio Durigan Junior  <sergiodj@redhat.com>

	* breakpoint.c (bkpt_probe_insert_location): Call set_semaphore
	only if it is not NULL.
	(bkpt_probe_remove_location): Likewise, for clear_semaphore.
	* probe.h (struct probe_ops) <set_semaphore>: Update comment.
	(struct probe_ops) <clear_semaphore>: Likewise.
	* tracepoint.c (start_tracing): Call set_semaphore only if it is
	not NULL.
	(stop_tracing): Likewise, for clear_semaphore.
This commit is contained in:
Sergio Durigan Junior 2014-10-14 14:45:13 -04:00
parent f7088df3b1
commit 0ea5cda861
4 changed files with 25 additions and 10 deletions
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11
gdb/ChangeLog
View file

@ -1,3 +1,14 @@
2014-10-14 Sergio Durigan Junior <sergiodj@redhat.com>
* breakpoint.c (bkpt_probe_insert_location): Call set_semaphore
only if it is not NULL.
(bkpt_probe_remove_location): Likewise, for clear_semaphore.
* probe.h (struct probe_ops) <set_semaphore>: Update comment.
(struct probe_ops) <clear_semaphore>: Likewise.
* tracepoint.c (start_tracing): Call set_semaphore only if it is
not NULL.
(stop_tracing): Likewise, for clear_semaphore.
2014-10-14 Sergio Durigan Junior <sergiodj@redhat.com>
* stap-probe.c (stap_parse_argument): Initialize expout explicitly

14
gdb/breakpoint.c
View file

@ -13696,9 +13696,10 @@ bkpt_probe_insert_location (struct bp_location *bl)
{
/* The insertion was successful, now let's set the probe's semaphore
if needed. */
bl->probe.probe->pops->set_semaphore (bl->probe.probe,
bl->probe.objfile,
bl->gdbarch);
if (bl->probe.probe->pops->set_semaphore != NULL)
bl->probe.probe->pops->set_semaphore (bl->probe.probe,
bl->probe.objfile,
bl->gdbarch);
}
return v;
@ -13708,9 +13709,10 @@ static int
bkpt_probe_remove_location (struct bp_location *bl)
{
/* Let's clear the semaphore before removing the location. */
bl->probe.probe->pops->clear_semaphore (bl->probe.probe,
bl->probe.objfile,
bl->gdbarch);
if (bl->probe.probe->pops->clear_semaphore != NULL)
bl->probe.probe->pops->clear_semaphore (bl->probe.probe,
bl->probe.objfile,
bl->gdbarch);
return bkpt_remove_location (bl);
}

4
gdb/probe.h
View file

@ -96,14 +96,14 @@ struct probe_ops
/* Set the semaphore associated with the PROBE. This function only makes
sense if the probe has a concept of semaphore associated to a
probe. */
probe, otherwise it can be set to NULL. */
void (*set_semaphore) (struct probe *probe, struct objfile *objfile,
struct gdbarch *gdbarch);
/* Clear the semaphore associated with the PROBE. This function only
makes sense if the probe has a concept of semaphore associated to
a probe. */
a probe, otherwise it can be set to NULL. */
void (*clear_semaphore) (struct probe *probe, struct objfile *objfile,
struct gdbarch *gdbarch);

6
gdb/tracepoint.c
View file

@ -1858,7 +1858,8 @@ start_tracing (char *notes)
t->number_on_target = b->number;
for (loc = b->loc; loc; loc = loc->next)
if (loc->probe.probe != NULL)
if (loc->probe.probe != NULL
&& loc->probe.probe->pops->set_semaphore != NULL)
loc->probe.probe->pops->set_semaphore (loc->probe.probe,
loc->probe.objfile,
loc->gdbarch);
@ -1957,7 +1958,8 @@ stop_tracing (char *note)
but we don't really care if this semaphore goes out of sync.
That's why we are decrementing it here, but not taking care
in other places. */
if (loc->probe.probe != NULL)
if (loc->probe.probe != NULL
&& loc->probe.probe->pops->clear_semaphore != NULL)
loc->probe.probe->pops->clear_semaphore (loc->probe.probe,
loc->probe.objfile,
loc->gdbarch);