[PATCH v3 14/44] gdb, infrun, ze: handle stopping unavailable threads

[Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>]

From: Markus Metzger <markus.t.metzger@intel.com>

On GPUs, threads may not always respond to interrupt requests.  In order
to still be able to support all-stop model on those targets, we allow this
case and model such threads as unavailable.

They do exist but we cannot interact with them.  In particular, they do
not have registers, including PC.

Use regcache_read_pc_protected () instead of regcache_read_pc () to
suppress an error when trying to access an unavailable thread's registers.
The thread's waitstatus will be TARGET_WAITKIND_UNAVAILABLE so there is
nothing extra to do here.
---
 gdb/infrun.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/gdb/infrun.c b/gdb/infrun.c
index 65392bc3b6f063fe65320d55b990b64a68a638a4..dc55e17b98a13dac14171a795574344ec2a3c545 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -5624,7 +5624,7 @@ handle_one (const wait_one_event &event)
 	    }
 
 	  regcache = get_thread_regcache (t);
-	  t->set_stop_pc (regcache_read_pc (regcache));
+	  t->set_stop_pc (regcache_read_pc_protected (regcache));
 
 	  infrun_debug_printf ("saved stop_pc=%s for %s "
 			       "(currently_stepping=%d)",
@@ -6251,7 +6251,8 @@ handle_inferior_event (struct execution_control_state *ecs)
 
 	    handle_solib_event ();
 
-	    ecs->event_thread->set_stop_pc (regcache_read_pc (regcache));
+	    ecs->event_thread->set_stop_pc
+	      (regcache_read_pc_protected (regcache));
 	    address_space *aspace = ecs->event_thread->inf->aspace.get ();
 	    ecs->event_thread->control.stop_bpstat
 	      = bpstat_stop_status_nowatch (aspace,

-- 
2.34.1

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