From 0ea5cda8612bd2233f7a2f9d1eba0b62c2e6c015 Mon Sep 17 00:00:00 2001 From: Sergio Durigan Junior Date: Tue, 14 Oct 2014 14:45:13 -0400 Subject: [PATCH] Only call {set,clear}_semaphore probe function if they are not NULL This patch is a response to what I commented on: 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 * 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) : Update comment. (struct probe_ops) : Likewise. * tracepoint.c (start_tracing): Call set_semaphore only if it is not NULL. (stop_tracing): Likewise, for clear_semaphore. --- gdb/ChangeLog | 11 +++++++++++ gdb/breakpoint.c | 14 ++++++++------ gdb/probe.h | 4 ++-- gdb/tracepoint.c | 6 ++++-- 4 files changed, 25 insertions(+), 10 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index ec050286bd4..57ddd7bf0d4 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,14 @@ +2014-10-14 Sergio Durigan Junior + + * 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) : Update comment. + (struct probe_ops) : 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 * stap-probe.c (stap_parse_argument): Initialize expout explicitly diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c index a144a7e96a9..dc2e297e47c 100644 --- a/gdb/breakpoint.c +++ b/gdb/breakpoint.c @@ -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); } diff --git a/gdb/probe.h b/gdb/probe.h index b4ff0a6b93b..a1281518ae7 100644 --- a/gdb/probe.h +++ b/gdb/probe.h @@ -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); diff --git a/gdb/tracepoint.c b/gdb/tracepoint.c index 51af2af2720..fc20063f62b 100644 --- a/gdb/tracepoint.c +++ b/gdb/tracepoint.c @@ -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); -- 2.30.2