8074980: add WhiteBox API to get a flag value for a method

Reviewed-by: kvn, fzhinkin

hotspot/src/share/vm/prims/whitebox.cpp

@@ -1133,6 +1133,75 @@ WB_ENTRY(void, WB_ForceSafepoint(JNIEnv* env, jobject wb))
   VMThread::execute(&force_safepoint_op);
 WB_END
 
+template <typename T>
+static bool GetMethodOption(JavaThread* thread, JNIEnv* env, jobject method, jstring name, T* value) {
+  assert(value != NULL, "sanity");
+  if (method == NULL || name == NULL) {
+    return false;
+  }
+  jmethodID jmid = reflected_method_to_jmid(thread, env, method);
+  CHECK_JNI_EXCEPTION_(env, false);
+  methodHandle mh(thread, Method::checked_resolve_jmethod_id(jmid));
+  // can't be in VM when we call JNI
+  ThreadToNativeFromVM ttnfv(thread);
+  const char* flag_name = env->GetStringUTFChars(name, NULL);
+  bool result =  CompilerOracle::has_option_value(mh, flag_name, *value);
+  env->ReleaseStringUTFChars(name, flag_name);
+  return result;
+}
+
+WB_ENTRY(jobject, WB_GetMethodBooleaneOption(JNIEnv* env, jobject wb, jobject method, jstring name))
+  bool result;
+  if (GetMethodOption<bool> (thread, env, method, name, &result)) {
+    // can't be in VM when we call JNI
+    ThreadToNativeFromVM ttnfv(thread);
+    return booleanBox(thread, env, result);
+  }
+  return NULL;
+WB_END
+
+WB_ENTRY(jobject, WB_GetMethodIntxOption(JNIEnv* env, jobject wb, jobject method, jstring name))
+  intx result;
+  if (GetMethodOption <intx> (thread, env, method, name, &result)) {
+    // can't be in VM when we call JNI
+    ThreadToNativeFromVM ttnfv(thread);
+    return longBox(thread, env, result);
+  }
+  return NULL;
+WB_END
+
+WB_ENTRY(jobject, WB_GetMethodUintxOption(JNIEnv* env, jobject wb, jobject method, jstring name))
+  uintx result;
+  if (GetMethodOption <uintx> (thread, env, method, name, &result)) {
+    // can't be in VM when we call JNI
+    ThreadToNativeFromVM ttnfv(thread);
+    return longBox(thread, env, result);
+  }
+  return NULL;
+WB_END
+
+WB_ENTRY(jobject, WB_GetMethodDoubleOption(JNIEnv* env, jobject wb, jobject method, jstring name))
+  double result;
+  if (GetMethodOption <double> (thread, env, method, name, &result)) {
+    // can't be in VM when we call JNI
+    ThreadToNativeFromVM ttnfv(thread);
+    return doubleBox(thread, env, result);
+  }
+  return NULL;
+WB_END
+
+WB_ENTRY(jobject, WB_GetMethodStringOption(JNIEnv* env, jobject wb, jobject method, jstring name))
+  ccstr ccstrResult;
+  if (GetMethodOption <ccstr> (thread, env, method, name, &ccstrResult)) {
+    // can't be in VM when we call JNI
+    ThreadToNativeFromVM ttnfv(thread);
+    jstring result = env->NewStringUTF(ccstrResult);
+    CHECK_JNI_EXCEPTION_(env, NULL);
+    return result;
+  }
+  return NULL;
+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) {
@@ -1333,6 +1402,21 @@ static JNINativeMethod methods[] = {
   {CC"assertMatchingSafepointCalls", CC"(ZZ)V",       (void*)&WB_AssertMatchingSafepointCalls },
   {CC"isMonitorInflated",  CC"(Ljava/lang/Object;)Z", (void*)&WB_IsMonitorInflated  },
   {CC"forceSafepoint",     CC"()V",                   (void*)&WB_ForceSafepoint     },
+  {CC"getMethodBooleanOption",
+      CC"(Ljava/lang/reflect/Executable;Ljava/lang/String;)Ljava/lang/Boolean;",
+                                                      (void*)&WB_GetMethodBooleaneOption},
+  {CC"getMethodIntxOption",
+      CC"(Ljava/lang/reflect/Executable;Ljava/lang/String;)Ljava/lang/Long;",
+                                                      (void*)&WB_GetMethodIntxOption},
+  {CC"getMethodUintxOption",
+      CC"(Ljava/lang/reflect/Executable;Ljava/lang/String;)Ljava/lang/Long;",
+                                                      (void*)&WB_GetMethodUintxOption},
+  {CC"getMethodDoubleOption",
+      CC"(Ljava/lang/reflect/Executable;Ljava/lang/String;)Ljava/lang/Double;",
+                                                      (void*)&WB_GetMethodDoubleOption},
+  {CC"getMethodStringOption",
+      CC"(Ljava/lang/reflect/Executable;Ljava/lang/String;)Ljava/lang/String;",
+                                                      (void*)&WB_GetMethodStringOption},
 };
 
 #undef CC

hotspot/test/compiler/oracle/GetMethodOptionTest.java

@@ -0,0 +1,104 @@
+/*
+ * Copyright (c) 2015, 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.
+ */
+
+import java.lang.reflect.Executable;
+import java.util.function.BiFunction;
+
+import com.oracle.java.testlibrary.Asserts;
+import sun.hotspot.WhiteBox;
+
+/*
+ * @test
+ * @bug 8074980
+ * @library /testlibrary /../../test/lib
+ * @build sun.hotspot.WhiteBox com.oracle.java.testlibrary.Asserts GetMethodOptionTest
+ * @run main ClassFileInstaller sun.hotspot.WhiteBox
+ *                              sun.hotspot.WhiteBox$WhiteBoxPermission
+ * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
+ *                   -XX:CompileCommand=option,GetMethodOptionTest::test,ccstrlist,MyListOption,_foo,_bar
+ *                   -XX:CompileCommand=option,GetMethodOptionTest::test,ccstr,MyStrOption,_foo
+ *                   -XX:CompileCommand=option,GetMethodOptionTest::test,bool,MyBoolOption,false
+ *                   -XX:CompileCommand=option,GetMethodOptionTest::test,intx,MyIntxOption,-1
+ *                   -XX:CompileCommand=option,GetMethodOptionTest::test,uintx,MyUintxOption,1
+ *                   -XX:CompileCommand=option,GetMethodOptionTest::test,MyFlag
+ *                   -XX:CompileCommand=option,GetMethodOptionTest::test,double,MyDoubleOption1,1.123
+ *                   -XX:CompileCommand=option,GetMethodOptionTest.test,double,MyDoubleOption2,1.123
+ *                   -XX:CompileCommand=option,GetMethodOptionTest::test,bool,MyBoolOptionX,false,intx,MyIntxOptionX,-1,uintx,MyUintxOptionX,1,MyFlagX,double,MyDoubleOptionX,1.123
+ *                   GetMethodOptionTest
+ */
+
+public class GetMethodOptionTest {
+    private static final  WhiteBox WB = WhiteBox.getWhiteBox();
+    public static void main(String[] args) {
+        Executable test = getMethod("test");
+        Executable test2 = getMethod("test2");
+        BiFunction<Executable, String, Object> getter = WB::getMethodOption;
+        for (TestCase testCase : TestCase.values()) {
+            Object expected = testCase.value;
+            String name = testCase.name();
+            Asserts.assertEQ(expected, getter.apply(test, name),
+                    testCase + ": universal getter returns wrong value");
+            Asserts.assertEQ(expected, testCase.getter.apply(test, name),
+                    testCase + ": specific getter returns wrong value");
+            Asserts.assertEQ(null, getter.apply(test2, name),
+                    testCase + ": universal getter returns value for unused method");
+            Asserts.assertEQ(null, testCase.getter.apply(test2, name),
+                    testCase + ": type specific getter returns value for unused method");
+        }
+    }
+    private static void test() { }
+    private static void test2() { }
+
+    private static enum TestCase {
+        MyListOption("_foo _bar", WB::getMethodStringOption),
+        MyStrOption("_foo", WB::getMethodStringOption),
+        MyBoolOption(false, WB::getMethodBooleanOption),
+        MyIntxOption(-1L, WB::getMethodIntxOption),
+        MyUintxOption(1L, WB::getMethodUintxOption),
+        MyFlag(true, WB::getMethodBooleanOption),
+        MyDoubleOption1(1.123d, WB::getMethodDoubleOption),
+        MyDoubleOption2(1.123d, WB::getMethodDoubleOption),
+        MyBoolOptionX(false, WB::getMethodBooleanOption),
+        MyIntxOptionX(-1L, WB::getMethodIntxOption),
+        MyUintxOptionX(1L, WB::getMethodUintxOption),
+        MyFlagX(true, WB::getMethodBooleanOption),
+        MyDoubleOptionX(1.123d, WB::getMethodDoubleOption);
+
+        public final Object value;
+        public final BiFunction<Executable, String, Object> getter;
+        private TestCase(Object value, BiFunction<Executable, String, Object> getter) {
+            this.value = value;
+            this.getter = getter;
+        }
+    }
+
+    private static Executable getMethod(String name) {
+        Executable result;
+        try {
+            result = GetMethodOptionTest.class.getDeclaredMethod(name);
+        } catch (NoSuchMethodException | SecurityException e) {
+            throw new Error("TESTBUG : can't get method " + name, e);
+        }
+        return result;
+    }
+}