On Tue, Oct 20, 2020 at 02:17:26PM +0200, Tobias Burnus wrote:
> On 10/20/20 2:11 PM, Tobias Burnus wrote:
> 
> > Unfortunately, the committed patch
> > (r11-4121-g1bfc07d150790fae93184a79a7cce897655cb37b)
> > causes build errors.
> > 
> > The error seems to be provoked by function cloning – as the code
> > itself looks fine:
> > ...
> >  struct gomp_device_descr *devices_s
> >     = malloc (num_devices * sizeof (struct gomp_device_descr));
> > ...
> >   for (i = 0; i < num_devices; i++)
> >     if (!(devices[i].capabilities & GOMP_OFFLOAD_CAP_OPENMP_400))
> >       devices_s[num_devices_after_openmp++] = devices[i];
> 
> gomp_target_init.part.0 ()
> {
> ...
> <bb 2>
>   devices_s_1 = malloc (0);
> ...
>   num_devices.16_67 = num_devices;
> ...
>   if (num_devices.16_67 > 0)
>     goto <bb 3>; [89.00%]
>   else
>     goto <bb 18>; [11.00%]
> 
> Which seems to have an ordering problem.

This patch fixes the warning that breaks the bootstrap, but haven't
tested it with offloading to see if it doesn't break offloading somehow.

2020-10-20  Jakub Jelinek  <ja...@redhat.com>

        * target.c (gomp_target_init): Inside of the function, use automatic
        variables corresponding to num_devices, num_devices_openmp and devices
        global variables and update the globals only at the end of the
        function.

--- libgomp/target.c.jj 2020-10-20 14:37:36.630967911 +0200
+++ libgomp/target.c    2020-10-20 14:52:36.556023803 +0200
@@ -3279,10 +3279,9 @@ gomp_target_init (void)
   const char *suffix = SONAME_SUFFIX (1);
   const char *cur, *next;
   char *plugin_name;
-  int i, new_num_devices;
-
-  num_devices = 0;
-  devices = NULL;
+  int i, new_num_devs;
+  int num_devs = 0, num_devs_openmp;
+  struct gomp_device_descr *devs = NULL;
 
   if (gomp_target_offload_var == GOMP_TARGET_OFFLOAD_DISABLED)
     return;
@@ -3303,7 +3302,7 @@ gomp_target_init (void)
        plugin_name = (char *) malloc (prefix_len + cur_len + suffix_len + 1);
        if (!plugin_name)
          {
-           num_devices = 0;
+           num_devs = 0;
            break;
          }
 
@@ -3313,16 +3312,16 @@ gomp_target_init (void)
 
        if (gomp_load_plugin_for_device (&current_device, plugin_name))
          {
-           new_num_devices = current_device.get_num_devices_func ();
-           if (new_num_devices >= 1)
+           new_num_devs = current_device.get_num_devices_func ();
+           if (new_num_devs >= 1)
              {
                /* Augment DEVICES and NUM_DEVICES.  */
 
-               devices = realloc (devices, (num_devices + new_num_devices)
-                                  * sizeof (struct gomp_device_descr));
-               if (!devices)
+               devs = realloc (devs, (num_devs + new_num_devs)
+                                     * sizeof (struct gomp_device_descr));
+               if (!devs)
                  {
-                   num_devices = 0;
+                   num_devs = 0;
                    free (plugin_name);
                    break;
                  }
@@ -3332,12 +3331,12 @@ gomp_target_init (void)
                current_device.type = current_device.get_type_func ();
                current_device.mem_map.root = NULL;
                current_device.state = GOMP_DEVICE_UNINITIALIZED;
-               for (i = 0; i < new_num_devices; i++)
+               for (i = 0; i < new_num_devs; i++)
                  {
                    current_device.target_id = i;
-                   devices[num_devices] = current_device;
-                   gomp_mutex_init (&devices[num_devices].lock);
-                   num_devices++;
+                   devs[num_devs] = current_device;
+                   gomp_mutex_init (&devs[num_devs].lock);
+                   num_devs++;
                  }
              }
          }
@@ -3349,34 +3348,37 @@ gomp_target_init (void)
 
   /* In DEVICES, sort the GOMP_OFFLOAD_CAP_OPENMP_400 ones first, and set
      NUM_DEVICES_OPENMP.  */
-  struct gomp_device_descr *devices_s
-    = malloc (num_devices * sizeof (struct gomp_device_descr));
-  if (!devices_s)
+  struct gomp_device_descr *devs_s
+    = malloc (num_devs * sizeof (struct gomp_device_descr));
+  if (!devs_s)
     {
-      num_devices = 0;
-      free (devices);
-      devices = NULL;
+      num_devs = 0;
+      free (devs);
+      devs = NULL;
     }
-  num_devices_openmp = 0;
-  for (i = 0; i < num_devices; i++)
-    if (devices[i].capabilities & GOMP_OFFLOAD_CAP_OPENMP_400)
-      devices_s[num_devices_openmp++] = devices[i];
-  int num_devices_after_openmp = num_devices_openmp;
-  for (i = 0; i < num_devices; i++)
-    if (!(devices[i].capabilities & GOMP_OFFLOAD_CAP_OPENMP_400))
-      devices_s[num_devices_after_openmp++] = devices[i];
-  free (devices);
-  devices = devices_s;
+  num_devs_openmp = 0;
+  for (i = 0; i < num_devs; i++)
+    if (devs[i].capabilities & GOMP_OFFLOAD_CAP_OPENMP_400)
+      devs_s[num_devs_openmp++] = devs[i];
+  int num_devs_after_openmp = num_devs_openmp;
+  for (i = 0; i < num_devs; i++)
+    if (!(devs[i].capabilities & GOMP_OFFLOAD_CAP_OPENMP_400))
+      devs_s[num_devs_after_openmp++] = devs[i];
+  free (devs);
+  devs = devs_s;
 
-  for (i = 0; i < num_devices; i++)
+  for (i = 0; i < num_devs; i++)
     {
       /* The 'devices' array can be moved (by the realloc call) until we have
         found all the plugins, so registering with the OpenACC runtime (which
         takes a copy of the pointer argument) must be delayed until now.  */
-      if (devices[i].capabilities & GOMP_OFFLOAD_CAP_OPENACC_200)
-       goacc_register (&devices[i]);
+      if (devs[i].capabilities & GOMP_OFFLOAD_CAP_OPENACC_200)
+       goacc_register (&devs[i]);
     }
 
+  num_devices = num_devs;
+  num_devices_openmp = num_devs_openmp;
+  devices = devs;
   if (atexit (gomp_target_fini) != 0)
     gomp_fatal ("atexit failed");
 }


        Jakub

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