8258471: "search codecache" clhsdb command does not work

Reviewed-by: cjplummer, sspitsyn

src/hotspot/share/runtime/vmStructs.cpp

@@ -1401,6 +1401,7 @@ typedef HashtableEntry<InstanceKlass*, mtClass>  KlassHashtableEntry;
   declare_type(BufferBlob,               RuntimeBlob)                     \
   declare_type(AdapterBlob,              BufferBlob)                      \
   declare_type(MethodHandlesAdapterBlob, BufferBlob)                      \
+  declare_type(VtableBlob,               BufferBlob)                      \
   declare_type(CompiledMethod,           CodeBlob)                        \
   declare_type(nmethod,                  CompiledMethod)                  \
   declare_type(RuntimeStub,              RuntimeBlob)                     \

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/code/CodeCache.java

@@ -64,6 +64,7 @@ public class CodeCache {
     virtualConstructor.addMapping("RuntimeStub", RuntimeStub.class);
     virtualConstructor.addMapping("AdapterBlob", AdapterBlob.class);
     virtualConstructor.addMapping("MethodHandlesAdapterBlob", MethodHandlesAdapterBlob.class);
+    virtualConstructor.addMapping("VtableBlob", VtableBlob.class);
     virtualConstructor.addMapping("SafepointBlob", SafepointBlob.class);
     virtualConstructor.addMapping("DeoptimizationBlob", DeoptimizationBlob.class);
     if (VM.getVM().isServerCompiler()) {
@@ -167,7 +168,7 @@ public class CodeCache {
     }
     catch (Exception e) {
       String message = "Unable to deduce type of CodeBlob from address " + codeBlobAddr +
-                       " (expected type nmethod, RuntimeStub, ";
+                       " (expected type nmethod, RuntimeStub, VtableBlob, ";
       if (VM.getVM().isClientCompiler()) {
         message = message + " or ";
       }

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/code/VtableBlob.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, NTT DATA.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+package sun.jvm.hotspot.code;
+
+import sun.jvm.hotspot.debugger.Address;
+
+public class VtableBlob extends BufferBlob {
+
+    public VtableBlob(Address addr) {
+        super(addr);
+    }
+
+    public boolean isVtableBlob() {
+        return true;
+    }
+
+    public String getName() {
+        return "VtableBlob: " + super.getName();
+    }
+
+}