opal/class: enable use of opal classes after opal_class_finalize

This commit enables the use of opal classes after a call to
opal_class_finalize. This is needed to support re-initializing opal
after calling opal_finalize_util (). This is needed to support the
following without leaking:

MPI_T_init_thread ();
MPI_T_finalize ();

MPI_Init ();
MPI_Finalize ();

Before this commit the above code would crash in MPI_Init because the
constructor array for some class was freed by opal_class_finalize ().

The fix is to turn the cls_initialized member of opal_class_t into an
init epoch identifier and compare it against opal_class_init_epoch
instead of 1. On each call to opal_class_finalize the
opal_class_init_epoch counter is incremented forcing re-initialization
of classes after finalize.

Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>

opal/class/opal_object.c

@@ -1,3 +1,4 @@
+/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
 /*
  * Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
  *                         University Research and Technology
@@ -9,6 +10,8 @@
  *                         University of Stuttgart.  All rights reserved.
  * Copyright (c) 2004-2005 The Regents of the University of California.
  *                         All rights reserved.
+ * Copyright (c) 2015      Los Alamos National Security, LLC. All rights
+ *                         reserved.
  * $COPYRIGHT$
  * 
  * Additional copyrights may follow
@@ -47,6 +50,8 @@ opal_class_t opal_object_t_class = {
     sizeof(opal_object_t) /* size of the opal object */
 };
 
+int opal_class_init_epoch = 1;
+
 /*
  * Local variables
  */
@@ -81,7 +86,7 @@ void opal_class_initialize(opal_class_t *cls)
     /* Check to see if any other thread got in here and initialized
        this class before we got a chance to */
 
-    if (1 == cls->cls_initialized) {
+    if (opal_class_init_epoch == cls->cls_initialized) {
         return;
     }
     opal_atomic_lock(&class_lock);
@@ -90,7 +95,7 @@ void opal_class_initialize(opal_class_t *cls)
        roughly the same time, it may have gotten the lock and
        initialized.  So check again. */
 
-    if (1 == cls->cls_initialized) {
+    if (opal_class_init_epoch == cls->cls_initialized) {
         opal_atomic_unlock(&class_lock);
         return;
     }
@@ -151,7 +156,7 @@ void opal_class_initialize(opal_class_t *cls)
     }
     *cls_destruct_array = NULL;  /* end marker for the destructors */
 
-    cls->cls_initialized = 1;
+    cls->cls_initialized = opal_class_init_epoch;
     save_class(cls);
 
     /* All done */
@@ -167,6 +172,12 @@ int opal_class_finalize(void)
 {
     int i;
 
+    if (INT_MAX == opal_class_init_epoch) {
+        opal_class_init_epoch = 1;
+    } else {
+        opal_class_init_epoch++;
+    }
+
     if (NULL != classes) {
         for (i = 0; i < num_classes; ++i) {
             if (NULL != classes[i]) { 

opal/class/opal_object.h

@@ -1,3 +1,4 @@
+/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
 /*
  * Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
  *                         University Research and Technology
@@ -10,6 +11,8 @@
  * Copyright (c) 2004-2005 The Regents of the University of California.
  *                         All rights reserved.
  * Copyright (c) 2007-2014 Cisco Systems, Inc.  All rights reserved.
+ * Copyright (c) 2015      Los Alamos National Security, LLC. All rights
+ *                         reserved.
  * $COPYRIGHT$
  * 
  * Additional copyrights may follow
@@ -161,6 +164,8 @@ struct opal_class_t {
     size_t cls_sizeof;              /**< size of an object instance */
 };
 
+extern int opal_class_init_epoch;
+
 /**
  * For static initializations of OBJects.
  *
@@ -344,8 +349,8 @@ do {                                                            \
 
 #define OBJ_CONSTRUCT_INTERNAL(object, type)                        \
 do {                                                                \
-    OBJ_SET_MAGIC_ID((object), OPAL_OBJ_MAGIC_ID);              \
-    if (0 == (type)->cls_initialized) {                             \
+    OBJ_SET_MAGIC_ID((object), OPAL_OBJ_MAGIC_ID);                  \
+    if (opal_class_init_epoch != (type)->cls_initialized) {         \
         opal_class_initialize((type));                              \
     }                                                               \
     ((opal_object_t *) (object))->obj_class = (type);               \
@@ -469,7 +474,7 @@ static inline opal_object_t *opal_obj_new(opal_class_t * cls)
 #else
     object = (opal_object_t *) malloc(cls->cls_sizeof);
 #endif
-    if (0 == cls->cls_initialized) {
+    if (opal_class_init_epoch != cls->cls_initialized) {
         opal_class_initialize(cls);
     }
     if (NULL != object) {