erts: Extend erl_driver interface with lock names

Lock and thread names are already a feature in the driver interface.
This extension will let developers read these names. Eases debugging.

erts/emulator/beam/erl_driver.h

@@ -546,6 +546,11 @@ EXTERN int erl_drv_equal_tids(ErlDrvTid tid1, ErlDrvTid tid2);
 EXTERN void erl_drv_thread_exit(void *resp);
 EXTERN int erl_drv_thread_join(ErlDrvTid, void **respp);
 
+EXTERN char* erl_drv_mutex_name(ErlDrvMutex *mtx);
+EXTERN char* erl_drv_cond_name(ErlDrvCond *cnd);
+EXTERN char* erl_drv_rwlock_name(ErlDrvRWLock *rwlck);
+EXTERN char* erl_drv_thread_name(ErlDrvTid tid);
+
 /*
  * Misc.
  */
@@ -681,6 +686,3 @@ EXTERN int erl_drv_getenv(char *key, char *value, size_t *value_size);
 
 /* also in global.h, but driver's can't include global.h */
 void dtrace_drvport_str(ErlDrvPort port, char *port_buf);
-
-
-

erts/emulator/beam/erl_drv_thread.c

@@ -188,6 +188,17 @@ erl_drv_mutex_destroy(ErlDrvMutex *dmtx)
 #endif
 }
 
+
+char *
+erl_drv_mutex_name(ErlDrvMutex *dmtx)
+{
+#ifdef USE_THREADS
+    return dmtx ? dmtx->name : NULL;
+#else
+    return NULL;
+#endif
+}
+
 int
 erl_drv_mutex_trylock(ErlDrvMutex *dmtx)
 {
@@ -258,6 +269,15 @@ erl_drv_cond_destroy(ErlDrvCond *dcnd)
 #endif
 }
 
+char *
+erl_drv_cond_name(ErlDrvCond *dcnd)
+{
+#ifdef USE_THREADS
+    return dcnd ? dcnd->name : NULL;
+#else
+    return NULL;
+#endif
+}
 
 void
 erl_drv_cond_signal(ErlDrvCond *dcnd)
@@ -331,6 +351,16 @@ erl_drv_rwlock_destroy(ErlDrvRWLock *drwlck)
 #endif
 }
 
+char *
+erl_drv_rwlock_name(ErlDrvRWLock *drwlck)
+{
+#ifdef USE_THREADS
+    return drwlck ? drwlck->name : NULL;
+#else
+    return NULL;
+#endif
+}
+
 int
 erl_drv_rwlock_tryrlock(ErlDrvRWLock *drwlck)
 {
@@ -617,6 +647,18 @@ erl_drv_thread_create(char *name,
 #endif
 }
 
+char *
+erl_drv_thread_name(ErlDrvTid tid)
+{
+#ifdef USE_THREADS
+    struct ErlDrvTid_ *dtid = (struct ErlDrvTid_ *) tid;
+    return dtid ? dtid->name : NULL;
+#else
+    return NULL;
+#endif
+}
+
+
 ErlDrvTid
 erl_drv_thread_self(void)
 {