wt: don't support a key as a union { ulonglong, void* }. Although convenient,

it forces the user to bzero a key before setting it as a pointer, otherwise
it'll have random content on architectures where
sizeof(void*) < sizeof(ulonglong).

Declaring a key as ulonglong only (not a union) makes this user mistake
impossible.

include/waiting_threads.h:
  WT_RESOURCE_ID::value is an ulonglong, not a union
mysys/waiting_threads.c:
  WT_RESOURCE_ID::value is an ulonglong, not a union
storage/maria/ma_write.c:
  WT_RESOURCE_ID::value is an ulonglong, not a union
storage/maria/trnman.c:
  WT_RESOURCE_ID::value is an ulonglong, not a union
unittest/mysys/waiting_threads-t.c:
  WT_RESOURCE_ID::value is an ulonglong, not a union

include/waiting_threads.h

@@ -32,10 +32,7 @@ typedef struct st_wt_resource_type {
 
 struct st_wt_resource_id {
   WT_RESOURCE_TYPE *type;
-  union {
-    void     *ptr;
-    ulonglong num;
-  } value;
+  ulonglong value;
 };
 
 #define WT_WAIT_STATS  24

mysys/waiting_threads.c

@@ -30,8 +30,7 @@
       A resource is represented by a WT_RESOURCE structure. 
 
     a resource identifier - a pair of {resource type, value}. A value is
-      either a ulonglong number or a pointer (it's a union).
-      WT_RESOURCE_ID structure.
+      an ulonglong number. Represented by a WT_RESOURCE_ID structure.
 
     a resource type - a pointer to a statically defined instance of
     WT_RESOURCE_TYPE structure. This structure contains a pointer to
@@ -169,20 +168,20 @@ static my_atomic_rwlock_t cycle_stats_lock, wait_stats_lock, success_stats_lock;
 #define rc_rdlock(X)                                                    \
   do {                                                                  \
     WT_RESOURCE *R=(X);                                                 \
-    DBUG_PRINT("wt", ("LOCK resid=%lld for READ", R->id.value.num));    \
-    rw_rdlock(&R->lock);                                    \
+    DBUG_PRINT("wt", ("LOCK resid=%lld for READ", R->id.value));        \
+    rw_rdlock(&R->lock);                                                \
   } while (0)
 #define rc_wrlock(X)                                                    \
   do {                                                                  \
     WT_RESOURCE *R=(X);                                                 \
-    DBUG_PRINT("wt", ("LOCK resid=%lld for WRITE", R->id.value.num));   \
-    rw_wrlock(&R->lock);                                    \
+    DBUG_PRINT("wt", ("LOCK resid=%lld for WRITE", R->id.value));       \
+    rw_wrlock(&R->lock);                                                \
   } while (0)
 #define rc_unlock(X)                                                    \
   do {                                                                  \
     WT_RESOURCE *R=(X);                                                 \
-    DBUG_PRINT("wt", ("UNLOCK resid=%lld", R->id.value.num));           \
-    rw_unlock(&R->lock);                                    \
+    DBUG_PRINT("wt", ("UNLOCK resid=%lld", R->id.value));               \
+    rw_unlock(&R->lock);                                                \
   } while (0)
 
 /*
@@ -688,7 +687,7 @@ int wt_thd_will_wait_for(WT_THD *thd, WT_THD *blocker, WT_RESOURCE_ID *resid)
   LF_REQUIRE_PINS(3);
 
   DBUG_PRINT("wt", ("enter: thd=%s, blocker=%s, resid=%llu",
-                    thd->name, blocker->name, resid->value.num));
+                    thd->name, blocker->name, resid->value));
 
   if (fix_thd_pins(thd))
     DBUG_RETURN(WT_DEADLOCK);

storage/maria/ma_write.c

@@ -217,7 +217,7 @@ int maria_write(MARIA_HA *info, uchar *record)
             int res;
 
             rc.type= &ma_rc_dup_unique;
-            rc.value.ptr= blocker; /* TODO savepoint id when we'll have them */
+            rc.value= (intptr)blocker; /* TODO savepoint id when we'll have them */
             res= wt_thd_will_wait_for(info->trn->wt, blocker->wt, & rc);
             if (res != WT_OK)
             {

storage/maria/trnman.c

@@ -87,7 +87,7 @@ static void wt_thd_release_self(TRN *trn)
   {
     WT_RESOURCE_ID rc;
     rc.type= &ma_rc_dup_unique;
-    rc.value.ptr= trn;
+    rc.value= (intptr)trn;
     wt_thd_release(trn->wt, & rc);
     trn->wt= 0;
   }

unittest/mysys/waiting_threads-t.c

@@ -62,9 +62,8 @@ pthread_handler_t test_wt(void *arg)
   {
     WT_RESOURCE_ID resid;
     int blockers[THREADS/10], j, k;
-    bzero(&resid, sizeof(resid));
 
-    resid.value.num= id;
+    resid.value= id;
     resid.type= &restype;
 
     res= 0;
@@ -187,8 +186,7 @@ void do_tests()
     WT_RESOURCE_ID resid[3];
     for (i=0; i < 3; i++)
     {
-      bzero(&resid[i], sizeof(resid[i]));
-      resid[i].value.num= i+1;
+      resid[i].value= i+1;
       resid[i].type= &restype;
     }