8009763: Add WB test for String.intern()

Summary: Add convenience method in StringTable, add WhiteBox method and simple sanity test
Reviewed-by: mgerdin, zgu
Contributed-by: leonid.mesnik@oracle.com

src/share/vm/classfile/symbolTable.cpp

@@ -677,9 +677,14 @@ oop StringTable::lookup(Symbol* symbol) {
   ResourceMark rm;
   int length;
   jchar* chars = symbol->as_unicode(length);
-  unsigned int hashValue = hash_string(chars, length);
-  int index = the_table()->hash_to_index(hashValue);
-  return the_table()->lookup(index, chars, length, hashValue);
+  return lookup(chars, length);
+}
+
+
+oop StringTable::lookup(jchar* name, int len) {
+  unsigned int hash = hash_string(name, len);
+  int index = the_table()->hash_to_index(hash);
+  return the_table()->lookup(index, name, len, hash);
 }
 
 

src/share/vm/classfile/symbolTable.hpp

@@ -287,6 +287,7 @@ public:
 
   // Probing
   static oop lookup(Symbol* symbol);
+  static oop lookup(jchar* chars, int length);
 
   // Interning
   static oop intern(Symbol* symbol, TRAPS);

src/share/vm/prims/whitebox.cpp

@@ -254,6 +254,24 @@ WB_ENTRY(jint, WB_GetCompileQueuesSize(JNIEnv* env, jobject o))
          CompileBroker::queue_size(CompLevel_full_profile) /* C1 */;
 WB_END
 
+WB_ENTRY(jboolean, WB_IsInStringTable(JNIEnv* env, jobject o, jstring javaString))
+  ResourceMark rm(THREAD);
+  int len;
+  jchar* name = java_lang_String::as_unicode_string(JNIHandles::resolve(javaString), len);
+  oop found_string = StringTable::the_table()->lookup(name, len);
+  if (found_string == NULL) {
+        return false;
+  }
+  return true;
+WB_END
+
+
+WB_ENTRY(void, WB_FullGC(JNIEnv* env, jobject o))
+  Universe::heap()->collector_policy()->set_should_clear_all_soft_refs(true);
+  Universe::heap()->collect(GCCause::_last_ditch_collection);
+WB_END
+
+
 //Some convenience methods to deal with objects from java
 int WhiteBox::offset_for_field(const char* field_name, oop object,
     Symbol* signature_symbol) {
@@ -343,6 +361,8 @@ static JNINativeMethod methods[] = {
       CC"(Ljava/lang/reflect/Method;)I",              (void*)&WB_GetMethodCompilationLevel},
   {CC"getCompileQueuesSize",
       CC"()I",                                        (void*)&WB_GetCompileQueuesSize},
+  {CC"isInStringTable",   CC"(Ljava/lang/String;)Z",  (void*)&WB_IsInStringTable  },
+  {CC"fullGC",   CC"()V",                             (void*)&WB_FullGC },
 };
 
 #undef CC

test/runtime/interned/SanityTest.java

+/*
+ * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+ * 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.
+ */
+
+/*
+ * @test SanityTest
+ * @summary Sanity check of String.intern() & GC
+ * @library /testlibrary /testlibrary/whitebox
+ * @build SanityTest
+ * @run main ClassFileInstaller sun.hotspot.WhiteBox
+ * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI SanityTest
+ */
+
+import java.util.*;
+import sun.hotspot.WhiteBox;
+
+
+public class SanityTest {
+    public static Object tmp;
+    public static void main(String... args) {
+
+        WhiteBox wb = WhiteBox.getWhiteBox();
+        StringBuilder sb = new StringBuilder();
+        sb.append("1234x"); sb.append("x56789");
+        String str = sb.toString();
+
+        if (wb.isInStringTable(str)) {
+            throw new RuntimeException("String " + str + " is already interned");
+        }
+        str.intern();
+        if (!wb.isInStringTable(str)) {
+            throw new RuntimeException("String " + str + " is not interned");
+        }
+        str = sb.toString();
+        wb.fullGC();
+        if (wb.isInStringTable(str)) {
+            throw new RuntimeException("String " + str + " is in StringTable even after GC");
+        }
+    }
+}

test/testlibrary/whitebox/sun/hotspot/WhiteBox.java

@@ -94,4 +94,10 @@ public class WhiteBox {
   public native int     getMethodCompilationLevel(Method method);
   public native boolean setDontInlineMethod(Method method, boolean value);
   public native int     getCompileQueuesSize();
+
+  //Intered strings
+  public native boolean isInStringTable(String str);
+
+  // force Full GC
+  public native void fullGC();
 }