Re: OpenACC: initialization with unsupported acc_device_t (was: [PR testsuite/65205, libgomp/65993] Fix dg-shouldfail usage in OpenACC libgomp tests)

[Julian Brown <julian at codesourcery dot com>]

On Tue, 5 May 2015 16:09:18 +0200
Thomas Schwinge <thomas@codesourcery.com> wrote:

> Hi!
> 
> On Tue, 5 May 2015 08:43:48 -0400, John David Anglin
> <dave.anglin@bell.net> wrote:
> > On 2015-05-05 5:43 AM, Thomas Schwinge wrote:
> > >> FAIL: libgomp.oacc-c/../libgomp.oacc-c-c++-common/lib-62.c
> > >> >-DACC_DEVICE_TYPE_hos
> > >> >t=1 -DACC_MEM_SHARED=1 output pattern test, is , should match
> > >> >invalid size
> > > With this one I'll need your help: please cite from libgomp.log
> > > (or, from a manual run) the actual output message that you're
> > > getting.
> > There's no output message:
> > # ./lib-62.exe
> > Segmentation fault (core dumped)

> As this is a PA-RISC HP-UX system, I feel certain that you don't
> actually have nvptx offloading available (so, the nvptx libgomp
> plugin is not being built).  However, this test case, contains an
> unconditional acc_init call for acc_device_nvidia, and I would then
> guess that this situation is not (not anymore?) correctly handled
> (abort with Âoffloading to [...] not possibleÂ, or similar; see
> libgomp.oacc-c-c++-common/lib-4.c) in libgomp -- Julian, could this be
> due to your recent libgomp OpenACC initialization changes?  (When
> working on this in a build that does have nvptx offloading
> configured, I think you should be able to simulate the situation by
> "hiding" (temporarily deleting, or similar) the nvptx libgomp
> plugin?)

The attached patch contains (what I hope should be) a fix for this,
tested by running the libgomp testsuite (with nvptx offloading), and by
deleting the nvptx plugin, with the patch applied, and ensuring that
lib-62.c no longer segfaults in that case.

The patch also tidies up a few other error paths around resolve_device,
and de-duplicates some error message reporting code.

> Then, I don't know why libgomp.oacc-c-c++-common/lib-62.c contains
> this explicit acc_init call with acc_device_nvidia -- generally, the
> test cases should not contain such unconditional statements.  So,
> let's then please remove this.  See
> libgomp/testsuite/libgomp.oacc-c-c++-common/lib-66.c for a very
> similar test case, which does this differently.

I've not touched this test though -- but I have tweaked
libgomp.oacc-c-c++-common/lib-4.c that should now expect a slightly
different error output.

OK for trunk?

Thanks,

Julian

ChangeLog

    libgomp/
    * oacc-init.c (resolve_device): Add FAIL_IS_ERROR argument. Update
    function comment. Only call gomp_fatal if new argument is true.
    (acc_dev_num_out_of_range): New function.
    (acc_init_1, acc_shutdown_1): Update call to resolve_device. Call
    acc_dev_num_out_of_range as appropriate.
    (acc_get_num_devices, acc_set_device_type, acc_get_device_type)
    (acc_get_device_num, acc_set_device_num): Update calls to resolve_device.
    * testsuite/libgomp.oacc-c-c++-common/lib-4.c: Update expected test
    output.

commit 221b5dea47cdb7611456ca3cf28d180d3ff1156a
Author: Julian Brown <julian@codesourcery.com>
Date:   Thu May 7 08:39:16 2015 -0700

    Clean up initialisation when no devices of a particular type are available.

diff --git a/libgomp/oacc-init.c b/libgomp/oacc-init.c
index f2c60ec..cd50521 100644
--- a/libgomp/oacc-init.c
+++ b/libgomp/oacc-init.c
@@ -109,10 +109,12 @@ name_of_acc_device_t (enum acc_device_t type)
     }
 }
 
-/* ACC_DEVICE_LOCK should be held before calling this function.  */
+/* ACC_DEVICE_LOCK must be held before calling this function.  If FAIL_IS_ERROR
+   is true, this function raises an error if there are no devices of type D,
+   otherwise it returns NULL in that case.  */
 
 static struct gomp_device_descr *
-resolve_device (acc_device_t d)
+resolve_device (acc_device_t d, bool fail_is_error)
 {
   acc_device_t d_arg = d;
 
@@ -130,7 +132,13 @@ resolve_device (acc_device_t d)
 		  && dispatchers[d]->get_num_devices_func () > 0)
 		goto found;
 
-	    gomp_fatal ("device type %s not supported", goacc_device_type);
+	    if (fail_is_error)
+	      {
+		gomp_mutex_unlock (&acc_device_lock);
+		gomp_fatal ("device type %s not supported", goacc_device_type);
+	      }
+	    else
+	      return NULL;
 	  }
 
 	/* No default device specified, so start scanning for any non-host
@@ -149,7 +157,13 @@ resolve_device (acc_device_t d)
 	  d = acc_device_host;
 	  goto found;
 	}
-      gomp_fatal ("no device found");
+      if (fail_is_error)
+        {
+	  gomp_mutex_unlock (&acc_device_lock);
+	  gomp_fatal ("no device found");
+	}
+      else
+        return NULL;
       break;
 
     case acc_device_host:
@@ -157,7 +171,12 @@ resolve_device (acc_device_t d)
 
     default:
       if (d > _ACC_device_hwm)
-	gomp_fatal ("device %u out of range", (unsigned)d);
+	{
+	  if (fail_is_error)
+	    goto unsupported_device;
+	  else
+	    return NULL;
+	}
       break;
     }
  found:
@@ -166,12 +185,30 @@ resolve_device (acc_device_t d)
 	  && d != acc_device_default
 	  && d != acc_device_not_host);
 
+  if (dispatchers[d] == NULL && fail_is_error)
+    {
+    unsupported_device:
+      gomp_mutex_unlock (&acc_device_lock);
+      gomp_fatal ("device type %s not supported", name_of_acc_device_t (d));
+    }
+
   return dispatchers[d];
 }
 
+/* Emit a suitable error if no device of a particular type is available, or
+   the given device number is out-of-range.  */
+static void
+acc_dev_num_out_of_range (acc_device_t d, int ord, int ndevs)
+{
+  if (ndevs == 0)
+    gomp_fatal ("no devices of type %s available", name_of_acc_device_t (d));
+  else
+    gomp_fatal ("device %u out of range", ord);
+}
+
 /* This is called when plugins have been initialized, and serves to call
    (indirectly) the target's device_init hook.  Calling multiple times without
-   an intervening acc_shutdown_1 call is an error.  ACC_DEVICE_LOCK should be
+   an intervening acc_shutdown_1 call is an error.  ACC_DEVICE_LOCK must be
    held before calling this function.  */
 
 static struct gomp_device_descr *
@@ -180,12 +217,12 @@ acc_init_1 (acc_device_t d)
   struct gomp_device_descr *base_dev, *acc_dev;
   int ndevs;
 
-  base_dev = resolve_device (d);
+  base_dev = resolve_device (d, true);
 
   ndevs = base_dev->get_num_devices_func ();
 
-  if (!base_dev || ndevs <= 0 || goacc_device_num >= ndevs)
-    gomp_fatal ("device %s not supported", name_of_acc_device_t (d));
+  if (ndevs <= 0 || goacc_device_num >= ndevs)
+    acc_dev_num_out_of_range (d, goacc_device_num, ndevs);
 
   acc_dev = &base_dev[goacc_device_num];
 
@@ -202,7 +239,7 @@ acc_init_1 (acc_device_t d)
   return base_dev;
 }
 
-/* ACC_DEVICE_LOCK should be held before calling this function.  */
+/* ACC_DEVICE_LOCK must be held before calling this function.  */
 
 static void
 acc_shutdown_1 (acc_device_t d)
@@ -213,10 +250,7 @@ acc_shutdown_1 (acc_device_t d)
   bool devices_active = false;
 
   /* Get the base device for this device type.  */
-  base_dev = resolve_device (d);
-
-  if (!base_dev)
-    gomp_fatal ("device %s not supported", name_of_acc_device_t (d));
+  base_dev = resolve_device (d, true);
 
   gomp_mutex_lock (&goacc_thread_lock);
 
@@ -364,7 +398,8 @@ goacc_attach_host_thread_to_device (int ord)
   
   num_devices = base_dev->get_num_devices_func ();
   if (num_devices <= 0 || ord >= num_devices)
-    gomp_fatal ("device %u out of range", ord);
+    acc_dev_num_out_of_range (acc_device_type (base_dev->type), ord,
+			      num_devices);
   
   if (!thr)
     thr = goacc_new_thread ();
@@ -424,7 +459,7 @@ acc_get_num_devices (acc_device_t d)
   gomp_init_targets_once ();
 
   gomp_mutex_lock (&acc_device_lock);
-  acc_dev = resolve_device (d);
+  acc_dev = resolve_device (d, false);
   gomp_mutex_unlock (&acc_device_lock);
 
   if (!acc_dev)
@@ -454,7 +489,7 @@ acc_set_device_type (acc_device_t d)
   if (!cached_base_dev)
     gomp_init_targets_once ();
 
-  cached_base_dev = base_dev = resolve_device (d);
+  cached_base_dev = base_dev = resolve_device (d, true);
   acc_dev = &base_dev[goacc_device_num];
 
   gomp_mutex_lock (&acc_dev->lock);
@@ -492,7 +527,7 @@ acc_get_device_type (void)
       gomp_init_targets_once ();
 
       gomp_mutex_lock (&acc_device_lock);
-      dev = resolve_device (acc_device_default);
+      dev = resolve_device (acc_device_default, true);
       gomp_mutex_unlock (&acc_device_lock);
       res = acc_device_type (dev->type);
     }
@@ -512,16 +547,14 @@ acc_get_device_num (acc_device_t d)
   struct goacc_thread *thr = goacc_thread ();
 
   if (d >= _ACC_device_hwm)
-    gomp_fatal ("device %u out of range", (unsigned)d);
+    gomp_fatal ("unknown device type %u", (unsigned) d);
 
   if (!cached_base_dev)
     gomp_init_targets_once ();
 
   gomp_mutex_lock (&acc_device_lock);
-  dev = resolve_device (d);
+  dev = resolve_device (d, true);
   gomp_mutex_unlock (&acc_device_lock);
-  if (!dev)
-    gomp_fatal ("device %s not supported", name_of_acc_device_t (d));
 
   if (thr && thr->base_dev == dev && thr->dev)
     return thr->dev->target_id;
@@ -552,12 +585,12 @@ acc_set_device_num (int ord, acc_device_t d)
     {
       gomp_mutex_lock (&acc_device_lock);
 
-      cached_base_dev = base_dev = resolve_device (d);
+      cached_base_dev = base_dev = resolve_device (d, true);
 
       num_devices = base_dev->get_num_devices_func ();
 
-      if (ord >= num_devices)
-        gomp_fatal ("device %u out of range", ord);
+      if (num_devices <= 0 || ord >= num_devices)
+        acc_dev_num_out_of_range (d, ord, num_devices);
 
       acc_dev = &base_dev[ord];
 
diff --git a/libgomp/testsuite/libgomp.oacc-c-c++-common/lib-4.c b/libgomp/testsuite/libgomp.oacc-c-c++-common/lib-4.c
index 35f9440..3bb9ea5 100644
--- a/libgomp/testsuite/libgomp.oacc-c-c++-common/lib-4.c
+++ b/libgomp/testsuite/libgomp.oacc-c-c++-common/lib-4.c
@@ -10,5 +10,5 @@ main (int argc, char **argv)
   return 0;
 }
 
-/* { dg-output "device \[0-9\]+ out of range" } */
+/* { dg-output "unknown device type \[0-9\]+" } */
 /* { dg-shouldfail "" } */