8255858: Add debug agent support for storing thread names

Reviewed-by: sspitsyn, amenkov

Author: plummercj

src/jdk.jdwp.agent/share/native/libjdwp/threadControl.c

@@ -84,6 +84,9 @@ typedef struct ThreadNode {
     struct ThreadNode *prev;
     jlong frameGeneration;
     struct ThreadList *list;  /* Tells us what list this thread is in */
+#ifdef DEBUG_THREADNAME
+    char name[256];
+#endif
 } ThreadNode;
 
 static jint suspendAllCount;
@@ -349,6 +352,22 @@ insertThread(JNIEnv *env, ThreadList *list, jthread thread)
         node->eventBag = eventBag;
         addNode(list, node);
 
+#ifdef DEBUG_THREADNAME
+        {
+            /* Set the thread name */
+            jvmtiThreadInfo info;
+            jvmtiError error;
+
+            memset(&info, 0, sizeof(info));
+            error = JVMTI_FUNC_PTR(gdata->jvmti,GetThreadInfo)
+                    (gdata->jvmti, node->thread, &info);
+            if (info.name != NULL) {
+                strncpy(node->name, info.name, sizeof(node->name) - 1);
+                jvmtiDeallocate(info.name);
+            }
+        }
+#endif
+
         /* Set thread local storage for quick thread -> node access.
          *   Some threads may not be in a state that allows setting of TLS,
          *   which is ok, see findThread, it deals with threads without TLS set.