changeset 3239:19c125efeda3

6939224: MethodHandle.invokeGeneric needs to perform the correct set of conversions Summary: JDK changes which run atop the corresponding JVM hook Reviewed-by: never, twisti
author jrose
date Sat, 30 Oct 2010 21:02:30 -0700
parents 4ed243e9e9d9
children 45f5055dd53f
files src/share/classes/java/dyn/MethodHandle.java src/share/classes/java/dyn/MethodHandles.java src/share/classes/sun/dyn/AdapterMethodHandle.java src/share/classes/sun/dyn/BoundMethodHandle.java src/share/classes/sun/dyn/InvokeGeneric.java src/share/classes/sun/dyn/Invokers.java src/share/classes/sun/dyn/MethodHandleImpl.java src/share/classes/sun/dyn/MethodHandleNatives.java src/share/classes/sun/dyn/MethodTypeImpl.java src/share/classes/sun/dyn/util/ValueConversions.java test/java/dyn/InvokeGenericTest.java test/java/dyn/MethodHandlesTest.java
diffstat 12 files changed, 847 insertions(+), 12 deletions(-) [+]
line wrap: on
line diff
--- a/src/share/classes/java/dyn/MethodHandle.java	Tue Sep 14 01:42:03 2010 -0700
+++ b/src/share/classes/java/dyn/MethodHandle.java	Sat Oct 30 21:02:30 2010 -0700
@@ -329,6 +329,7 @@
     public final Object invokeVarargs(Object... arguments) throws Throwable {
         int argc = arguments == null ? 0 : arguments.length;
         MethodType type = type();
+        if (type.parameterCount() != argc)  throw badParameterCount(type, argc);
         if (argc <= 10) {
             MethodHandle invoker = MethodHandles.invokers(type).genericInvoker();
             switch (argc) {
@@ -377,6 +378,10 @@
         return invokeVarargs(arguments.toArray());
     }
 
+    private static WrongMethodTypeException badParameterCount(MethodType type, int argc) {
+        return new WrongMethodTypeException(type+" does not take "+argc+" parameters");
+    }
+
     /*  --- this is intentionally NOT a javadoc yet ---
      * <em>PROVISIONAL API, WORK IN PROGRESS:</em>
      * Produce an adapter method handle which adapts the type of the
@@ -446,7 +451,7 @@
      * @throws IllegalArgumentException if the conversion cannot be made
      * @see MethodHandles#convertArguments
      */
-    public final MethodHandle asType(MethodType newType) {
+    public MethodHandle asType(MethodType newType) {
         return MethodHandles.convertArguments(this, newType);
     }
 
--- a/src/share/classes/java/dyn/MethodHandles.java	Tue Sep 14 01:42:03 2010 -0700
+++ b/src/share/classes/java/dyn/MethodHandles.java	Sat Oct 30 21:02:30 2010 -0700
@@ -1068,10 +1068,14 @@
         MethodType oldType = target.type();
         if (oldType.equals(newType))
             return target;
-        MethodHandle res = MethodHandleImpl.convertArguments(IMPL_TOKEN, target,
-                                                 newType, oldType, null);
+        MethodHandle res = null;
+        try {
+            res = MethodHandleImpl.convertArguments(IMPL_TOKEN, target,
+                                                    newType, oldType, null);
+        } catch (IllegalArgumentException ex) {
+        }
         if (res == null)
-            throw newIllegalArgumentException("cannot convert to "+newType+": "+target);
+            throw new WrongMethodTypeException("cannot convert to "+newType+": "+target);
         return res;
     }
 
@@ -1392,6 +1396,20 @@
         return adapter;
     }
 
+    /** Apply the given filter function to the return value of the given target.
+     */
+    /*public*/ static
+    MethodHandle filterReturnValue(MethodHandle target, MethodHandle filter) {
+        MethodType targetType = target.type();
+        MethodType filterType = filter.type();
+        if (filterType.parameterCount() != 1
+            || filterType.parameterType(0) != targetType.returnType())
+            throw newIllegalArgumentException("target and filter types do not match");
+        // FIXME: Too many nodes here.
+        MethodHandle returner = dropArguments(filter, 0, targetType.parameterList());
+        return foldArguments(returner, exactInvoker(target.type()).bindTo(target));
+    }
+
     /**
      * <em>PROVISIONAL API, WORK IN PROGRESS:</em>
      * Adapt a target method handle {@code target} by pre-processing
@@ -1434,7 +1452,7 @@
      * @return method handle which incorporates the specified argument folding logic
      * @throws IllegalArgumentException if the first argument type of
      *          {@code target} is not the same as {@code combiner}'s return type,
-     *          or if the next {@code foldArgs} argument types of {@code target}
+     *          or if the following argument types of {@code target}
      *          are not identical with the argument types of {@code combiner}
      */
     public static
@@ -1443,12 +1461,39 @@
         MethodType combinerType = combiner.type();
         int foldArgs = combinerType.parameterCount();
         boolean ok = (targetType.parameterCount() >= 1 + foldArgs);
+        if (ok && !combinerType.parameterList().equals(targetType.parameterList().subList(1, foldArgs+1)))
+            ok = false;
+        if (ok && !combinerType.returnType().equals(targetType.parameterType(0)))
+            ok = false;
         if (!ok)
             throw misMatchedTypes("target and combiner types", targetType, combinerType);
         MethodType newType = targetType.dropParameterTypes(0, 1);
         return MethodHandleImpl.foldArguments(IMPL_TOKEN, target, newType, combiner);
     }
 
+    // /**
+    //  * <em>PROVISIONAL API, WORK IN PROGRESS:</em>
+    //  * Adapt a target method handle {@code target} by pre-processing
+    //  * some of its arguments to derive a new target method handle.
+    //  * Call the new target on the original arguments.
+    //  * @param combined method handle to call initially on the incoming arguments
+    //  * @return method handle which incorporates the specified dispatching logic
+    //  * @throws IllegalArgumentException if the first argument type of
+    //  *          {@code combiner}'s return type is not {@link MethodHandle},
+    //  *          or if the next argument types of {@code target}
+    //  *          are not identical with the argument types of {@code combiner}
+    //  */
+    // public static
+    // MethodHandle dispatchArguments(MethodType targetType, MethodHandle dispatcher) {
+    //     MethodType dispatcherType = dispatcher.type();
+    //     int foldArgs = dispatcherType.parameterCount();
+    //     boolean ok = (targetType.parameterCount() >= foldArgs);
+    //     if (!ok)
+    //         throw misMatchedTypes("target and dispatcher types", targetType, dispatcherType);
+    //     MethodHandle target = exactInvoker(targetType);
+    //     return MethodHandleImpl.foldArguments(IMPL_TOKEN, target, targetType, dispatcher);
+    // }
+
     /**
      * <em>PROVISIONAL API, WORK IN PROGRESS:</em>
      * Make a method handle which adapts a target method handle,
@@ -1691,4 +1736,9 @@
         }
         return null;
     }
+
+    /*non-public*/
+    static MethodHandle withTypeHandler(MethodHandle target, MethodHandle typeHandler) {
+        return MethodHandleImpl.withTypeHandler(IMPL_TOKEN, target, typeHandler);
+    }
 }
--- a/src/share/classes/sun/dyn/AdapterMethodHandle.java	Tue Sep 14 01:42:03 2010 -0700
+++ b/src/share/classes/sun/dyn/AdapterMethodHandle.java	Sat Oct 30 21:02:30 2010 -0700
@@ -478,6 +478,39 @@
         return new AdapterMethodHandle(target, newType, makeConv(raw ? OP_RETYPE_RAW : OP_RETYPE_ONLY));
     }
 
+    static MethodHandle makeTypeHandler(Access token,
+                MethodHandle target, MethodHandle typeHandler) {
+        Access.check(token);
+        return new WithTypeHandler(target, typeHandler);
+    }
+
+    static class WithTypeHandler extends AdapterMethodHandle {
+        final MethodHandle target, typeHandler;
+        WithTypeHandler(MethodHandle target, MethodHandle typeHandler) {
+            super(target, target.type(), OP_RETYPE_ONLY);
+            this.target = target;
+            this.typeHandler = typeHandler.asType(TYPE_HANDLER_TYPE);
+        }
+
+        public MethodHandle asType(MethodType newType) {
+            if (this.type() == newType)
+                return this;
+            try {
+                MethodHandle retyped = (MethodHandle) typeHandler.<MethodHandle>invokeExact(target, newType);
+                // Contract:  Must return the desired type, or throw WMT
+                if (retyped.type() != newType)
+                    throw new WrongMethodTypeException(retyped.toString());
+                return retyped;
+            } catch (Throwable ex) {
+                if (ex instanceof Error)  throw (Error)ex;
+                if (ex instanceof RuntimeException)  throw (RuntimeException)ex;
+                throw new RuntimeException(ex);
+            }
+        }
+        private static final MethodType TYPE_HANDLER_TYPE
+            = MethodType.methodType(MethodHandle.class, MethodHandle.class, MethodType.class);
+    }
+
     /** Can a checkcast adapter validly convert the target to newType?
      *  The JVM supports all kind of reference casts, even silly ones.
      */
--- a/src/share/classes/sun/dyn/BoundMethodHandle.java	Tue Sep 14 01:42:03 2010 -0700
+++ b/src/share/classes/sun/dyn/BoundMethodHandle.java	Sat Oct 30 21:02:30 2010 -0700
@@ -103,7 +103,7 @@
         super(Access.TOKEN, type);
         this.argument = argument;
         this.vmargslot = vmargslot;
-        assert(this.getClass() == AdapterMethodHandle.class);
+        assert(this instanceof AdapterMethodHandle);
     }
 
     /** Initialize the current object as a Java method handle, binding it
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/classes/sun/dyn/InvokeGeneric.java	Sat Oct 30 21:02:30 2010 -0700
@@ -0,0 +1,160 @@
+/*
+ * Copyright (c) 2009, 2010, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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.dyn;
+
+import java.dyn.*;
+import java.lang.reflect.*;
+import sun.dyn.util.*;
+
+/**
+ * Adapters which manage MethodHanndle.invokeGeneric calls.
+ * The JVM calls one of these when the exact type match fails.
+ * @author jrose
+ */
+class InvokeGeneric {
+    // erased type for the call, which originates from an invokeGeneric site
+    private final MethodType erasedCallerType;
+    // an invoker of type (MT, MH; A...) -> R
+    private final MethodHandle initialInvoker;
+
+    /** Compute and cache information for this adapter, so that it can
+     *  call out to targets of the erasure-family of the given erased type.
+     */
+    private InvokeGeneric(MethodType erasedCallerType) throws NoAccessException {
+        this.erasedCallerType = erasedCallerType;
+        this.initialInvoker = makeInitialInvoker();
+        assert initialInvoker.type().equals(erasedCallerType
+                                            .insertParameterTypes(0, MethodType.class, MethodHandle.class))
+            : initialInvoker.type();
+    }
+
+    private static MethodHandles.Lookup lookup() {
+        return MethodHandleImpl.IMPL_LOOKUP;
+    }
+
+    /** Return the adapter information for this type's erasure. */
+    static MethodHandle genericInvokerOf(MethodType type) {
+        MethodTypeImpl form = MethodTypeImpl.of(type);
+        MethodHandle genericInvoker = form.genericInvoker;
+        if (genericInvoker == null) {
+            try {
+                InvokeGeneric gen = new InvokeGeneric(form.erasedType());
+                form.genericInvoker = genericInvoker = gen.initialInvoker;
+            } catch (NoAccessException ex) {
+                throw new RuntimeException(ex);
+            }
+        }
+        return genericInvoker;
+    }
+
+    private MethodHandle makeInitialInvoker() throws NoAccessException {
+        // postDispatch = #(MH'; MT, MH; A...){MH'(MT, MH; A)}
+        MethodHandle postDispatch = makePostDispatchInvoker();
+        MethodHandle invoker;
+        if (returnConversionPossible()) {
+            invoker = MethodHandles.foldArguments(postDispatch,
+                                                  dispatcher("dispatchWithConversion"));
+        } else {
+            invoker = MethodHandles.foldArguments(postDispatch, dispatcher("dispatch"));
+        }
+        return invoker;
+    }
+
+    private static final Class<?>[] EXTRA_ARGS = { MethodType.class, MethodHandle.class };
+    private MethodHandle makePostDispatchInvoker() {
+        // Take (MH'; MT, MH; A...) and run MH'(MT, MH; A...).
+        MethodType invokerType = erasedCallerType.insertParameterTypes(0, EXTRA_ARGS);
+        return MethodHandles.exactInvoker(invokerType);
+    }
+    private MethodHandle dropDispatchArguments(MethodHandle targetInvoker) {
+        assert(targetInvoker.type().parameterType(0) == MethodHandle.class);
+        return MethodHandles.dropArguments(targetInvoker, 1, EXTRA_ARGS);
+    }
+
+    private MethodHandle dispatcher(String dispatchName) throws NoAccessException {
+        return lookup().bind(this, dispatchName,
+                             MethodType.methodType(MethodHandle.class,
+                                                   MethodType.class, MethodHandle.class));
+    }
+
+    static final boolean USE_AS_TYPE_PATH = true;
+
+    /** Return a method handle to invoke on the callerType, target, and remaining arguments.
+     *  The method handle must finish the call.
+     *  This is the first look at the caller type and target.
+     */
+    private MethodHandle dispatch(MethodType callerType, MethodHandle target) {
+        MethodType targetType = target.type();
+        if (USE_AS_TYPE_PATH || target instanceof AdapterMethodHandle.WithTypeHandler) {
+            MethodHandle newTarget = target.asType(callerType);
+            targetType = callerType;
+            Invokers invokers = MethodTypeImpl.invokers(Access.TOKEN, targetType);
+            MethodHandle invoker = invokers.erasedInvokerWithDrops;
+            if (invoker == null) {
+                invokers.erasedInvokerWithDrops = invoker =
+                    dropDispatchArguments(invokers.erasedInvoker());
+            }
+            return invoker.bindTo(newTarget);
+        }
+        throw new RuntimeException("NYI");
+    }
+
+    private MethodHandle dispatchWithConversion(MethodType callerType, MethodHandle target) {
+        MethodHandle finisher = dispatch(callerType, target);
+        if (returnConversionNeeded(callerType, target))
+            finisher = addReturnConversion(finisher, callerType.returnType());  //FIXME: slow
+        return finisher;
+    }
+
+    private boolean returnConversionPossible() {
+        Class<?> needType = erasedCallerType.returnType();
+        return !needType.isPrimitive();
+    }
+    private boolean returnConversionNeeded(MethodType callerType, MethodHandle target) {
+        Class<?> needType = callerType.returnType();
+        if (needType == erasedCallerType.returnType())
+            return false;  // no conversions possible, since must be primitive or Object
+        Class<?> haveType = target.type().returnType();
+        if (VerifyType.isNullConversion(haveType, needType))
+            return false;
+        return true;
+    }
+    private MethodHandle addReturnConversion(MethodHandle target, Class<?> type) {
+        if (true) throw new RuntimeException("NYI");
+        // FIXME: This is slow because it creates a closure node on every call that requires a return cast.
+        MethodType targetType = target.type();
+        MethodHandle caster = ValueConversions.identity(type);
+        caster = caster.asType(MethodType.methodType(type, targetType.returnType()));
+        // Drop irrelevant arguments, because we only care about the return value:
+        caster = MethodHandles.dropArguments(caster, 1, targetType.parameterList());
+        MethodHandle result = MethodHandles.foldArguments(caster, target);
+        return result.asType(target.type());
+    }
+
+    public String toString() {
+        return "InvokeGeneric"+erasedCallerType;
+    }
+}
--- a/src/share/classes/sun/dyn/Invokers.java	Tue Sep 14 01:42:03 2010 -0700
+++ b/src/share/classes/sun/dyn/Invokers.java	Sat Oct 30 21:02:30 2010 -0700
@@ -38,6 +38,10 @@
     // exact invoker for the outgoing call
     private /*lazy*/ MethodHandle exactInvoker;
 
+    // erased (partially untyped but with primitives) invoker for the outgoing call
+    private /*lazy*/ MethodHandle erasedInvoker;
+    /*lazy*/ MethodHandle erasedInvokerWithDrops;  // for InvokeGeneric
+
     // generic (untyped) invoker for the outgoing call
     private /*lazy*/ MethodHandle genericInvoker;
 
@@ -80,6 +84,19 @@
         return invoker;
     }
 
+    public MethodHandle erasedInvoker() {
+        MethodHandle invoker1 = exactInvoker();
+        MethodHandle invoker = erasedInvoker;
+        if (invoker != null)  return invoker;
+        MethodType erasedType = targetType.erase();
+        if (erasedType == targetType.generic())
+            invoker = genericInvoker();
+        else
+            invoker = MethodHandles.convertArguments(invoker1, invokerType(erasedType));
+        erasedInvoker = invoker;
+        return invoker;
+    }
+
     public MethodHandle varargsInvoker(int objectArgCount) {
         MethodHandle vaInvoker = varargsInvokers[objectArgCount];
         if (vaInvoker != null)  return vaInvoker;
--- a/src/share/classes/sun/dyn/MethodHandleImpl.java	Tue Sep 14 01:42:03 2010 -0700
+++ b/src/share/classes/sun/dyn/MethodHandleImpl.java	Sat Oct 30 21:02:30 2010 -0700
@@ -560,7 +560,9 @@
     MethodHandle bindReceiver(Access token,
                               MethodHandle target, Object receiver) {
         Access.check(token);
-        if (target instanceof AdapterMethodHandle) {
+        if (target instanceof AdapterMethodHandle &&
+            ((AdapterMethodHandle)target).conversionOp() == MethodHandleNatives.Constants.OP_RETYPE_ONLY
+            ) {
             Object info = MethodHandleNatives.getTargetInfo(target);
             if (info instanceof DirectMethodHandle) {
                 DirectMethodHandle dmh = (DirectMethodHandle) info;
@@ -1257,4 +1259,9 @@
         Access.check(token);
         return MethodHandleNatives.getBootstrap(callerClass);
     }
+
+    public static MethodHandle withTypeHandler(Access token, MethodHandle target, MethodHandle typeHandler) {
+        Access.check(token);
+        return AdapterMethodHandle.makeTypeHandler(token, target, typeHandler);
+    }
 }
--- a/src/share/classes/sun/dyn/MethodHandleNatives.java	Tue Sep 14 01:42:03 2010 -0700
+++ b/src/share/classes/sun/dyn/MethodHandleNatives.java	Sat Oct 30 21:02:30 2010 -0700
@@ -317,6 +317,20 @@
     }
 
     /**
+     * The JVM wants to use a MethodType with invokeGeneric.  Give the runtime fair warning.
+     */
+    static void notifyGenericMethodType(MethodType type) {
+        try {
+            // Trigger adapter creation.
+            InvokeGeneric.genericInvokerOf(type);
+        } catch (Exception ex) {
+            Error err = new InternalError("Exception while resolving invokeGeneric");
+            err.initCause(ex);
+            throw err;
+        }
+    }
+
+    /**
      * The JVM is resolving a CONSTANT_MethodHandle CP entry.  And it wants our help.
      * It will make an up-call to this method.  (Do not change the name or signature.)
      */
--- a/src/share/classes/sun/dyn/MethodTypeImpl.java	Tue Sep 14 01:42:03 2010 -0700
+++ b/src/share/classes/sun/dyn/MethodTypeImpl.java	Sat Oct 30 21:02:30 2010 -0700
@@ -48,6 +48,7 @@
     final long primCounts;              // packed prim & double counts
     final int vmslots;                  // total number of parameter slots
     final MethodType erasedType;        // the canonical erasure
+
     /*lazy*/ MethodType primsAsBoxes;   // replace prims by wrappers
     /*lazy*/ MethodType primArgsAsBoxes; // wrap args only; make raw return
     /*lazy*/ MethodType primsAsInts;    // replace prims by int/long
@@ -59,6 +60,7 @@
     /*lazy*/ FromGeneric fromGeneric;   // convert cs. w/o prims to with
     /*lazy*/ SpreadGeneric[] spreadGeneric; // expand one argument to many
     /*lazy*/ FilterGeneric filterGeneric; // convert argument(s) on the fly
+    /*lazy*/ MethodHandle genericInvoker; // hook for invokeGeneric
 
     public MethodType erasedType() {
         return erasedType;
--- a/src/share/classes/sun/dyn/util/ValueConversions.java	Tue Sep 14 01:42:03 2010 -0700
+++ b/src/share/classes/sun/dyn/util/ValueConversions.java	Sat Oct 30 21:02:30 2010 -0700
@@ -377,7 +377,7 @@
             REBOX_CONVERSIONS = newWrapperCaches(2);
 
     /**
-     * Becase we normalize primitive types to reduce the number of signatures,
+     * Because we normalize primitive types to reduce the number of signatures,
      * primitives are sometimes manipulated under an "erased" type,
      * either int (for types other than long/double) or long (for all types).
      * When the erased primitive value is then boxed into an Integer or Long,
@@ -475,10 +475,10 @@
     }
 
     private static final EnumMap<Wrapper, MethodHandle>[]
-            ZERO_CONSTANT_FUNCTIONS = newWrapperCaches(1);
+            CONSTANT_FUNCTIONS = newWrapperCaches(2);
 
     public static MethodHandle zeroConstantFunction(Wrapper wrap) {
-        EnumMap<Wrapper, MethodHandle> cache = ZERO_CONSTANT_FUNCTIONS[0];
+        EnumMap<Wrapper, MethodHandle> cache = CONSTANT_FUNCTIONS[0];
         MethodHandle mh = cache.get(wrap);
         if (mh != null) {
             return mh;
@@ -544,6 +544,24 @@
     }
 
     /**
+     * Identity function on ints.
+     * @param x an arbitrary int value
+     * @return the same value x
+     */
+    static int identity(int x) {
+        return x;
+    }
+
+    /**
+     * Identity function on longs.
+     * @param x an arbitrary long value
+     * @return the same value x
+     */
+    static long identity(long x) {
+        return x;
+    }
+
+    /**
      * Identity function, with reference cast.
      * @param t an arbitrary reference type
      * @param x an arbitrary reference value
@@ -553,7 +571,7 @@
         return t.cast(x);
     }
 
-    private static final MethodHandle IDENTITY, CAST_REFERENCE, ALWAYS_NULL, ALWAYS_ZERO, ZERO_OBJECT, IGNORE, EMPTY;
+    private static final MethodHandle IDENTITY, IDENTITY_I, IDENTITY_J, CAST_REFERENCE, ALWAYS_NULL, ALWAYS_ZERO, ZERO_OBJECT, IGNORE, EMPTY;
     static {
         try {
             MethodType idType = MethodType.genericMethodType(1);
@@ -562,6 +580,8 @@
             MethodType ignoreType = idType.changeReturnType(void.class);
             MethodType zeroObjectType = MethodType.genericMethodType(0);
             IDENTITY = IMPL_LOOKUP.findStatic(ValueConversions.class, "identity", idType);
+            IDENTITY_I = IMPL_LOOKUP.findStatic(ValueConversions.class, "identity", MethodType.methodType(int.class, int.class));
+            IDENTITY_J = IMPL_LOOKUP.findStatic(ValueConversions.class, "identity", MethodType.methodType(long.class, long.class));
             //CAST_REFERENCE = IMPL_LOOKUP.findVirtual(Class.class, "cast", idType);
             CAST_REFERENCE = IMPL_LOOKUP.findStatic(ValueConversions.class, "castReference", castType);
             ALWAYS_NULL = IMPL_LOOKUP.findStatic(ValueConversions.class, "alwaysNull", idType);
@@ -613,6 +633,49 @@
         return IDENTITY;
     }
 
+    public static MethodHandle identity(Class<?> type) {
+        if (type == Object.class)
+            return IDENTITY;
+        else if (!type.isPrimitive())
+            return retype(MethodType.methodType(type, type), IDENTITY);
+        else
+            return identity(Wrapper.forPrimitiveType(type));
+    }
+
+    static MethodHandle identity(Wrapper wrap) {
+        EnumMap<Wrapper, MethodHandle> cache = CONSTANT_FUNCTIONS[1];
+        MethodHandle mh = cache.get(wrap);
+        if (mh != null) {
+            return mh;
+        }
+        // slow path
+        MethodType type = MethodType.methodType(wrap.primitiveType(), wrap.primitiveType());
+        try {
+            mh = IMPL_LOOKUP.findStatic(ValueConversions.class, "identity", type);
+        } catch (NoAccessException ex) {
+            mh = null;
+        }
+        if (mh == null && wrap == Wrapper.VOID) {
+            mh = EMPTY;  // #(){} : #()void
+        }
+        if (mh != null) {
+            cache.put(wrap, mh);
+            return mh;
+        }
+
+        // use a raw conversion
+        if (wrap.isSingleWord() && wrap != Wrapper.INT) {
+            mh = retype(type, identity(Wrapper.INT));
+        } else if (wrap.isDoubleWord() && wrap != Wrapper.LONG) {
+            mh = retype(type, identity(Wrapper.LONG));
+        }
+        if (mh != null) {
+            cache.put(wrap, mh);
+            return mh;
+        }
+        throw new IllegalArgumentException("cannot find identity for " + wrap);
+    }
+
     private static MethodHandle retype(MethodType type, MethodHandle mh) {
         return AdapterMethodHandle.makeRetypeOnly(IMPL_TOKEN, type, mh);
     }
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/java/dyn/InvokeGenericTest.java	Sat Oct 30 21:02:30 2010 -0700
@@ -0,0 +1,484 @@
+/*
+ * Copyright (c) 2009, 2010, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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
+ * @summary unit tests for java.dyn.MethodHandle.invokeGeneric
+ * @compile -target 7 InvokeGenericTest.java
+ * @run junit/othervm -XX:+UnlockExperimentalVMOptions -XX:+EnableMethodHandles test.java.dyn.InvokeGenericTest
+ */
+
+package test.java.dyn;
+
+import java.dyn.*;
+import static java.dyn.MethodHandles.*;
+import static java.dyn.MethodType.*;
+import java.lang.reflect.*;
+import java.util.*;
+import org.junit.*;
+import static org.junit.Assert.*;
+import static org.junit.Assume.*;
+
+
+/**
+ *
+ * @author jrose
+ */
+public class InvokeGenericTest {
+    // How much output?
+    static int verbosity = 0;
+    static {
+        String vstr = System.getProperty("test.java.dyn.InvokeGenericTest.verbosity");
+        if (vstr != null)  verbosity = Integer.parseInt(vstr);
+    }
+
+    @Test
+    public void testFirst() throws Throwable {
+        verbosity += 9; try {
+            // left blank for debugging
+        } finally { printCounts(); verbosity -= 9; }
+    }
+
+    public InvokeGenericTest() {
+    }
+
+    @Before
+    public void checkImplementedPlatform() {
+        boolean platformOK = false;
+        Properties properties = System.getProperties();
+        String vers = properties.getProperty("java.vm.version");
+        String name = properties.getProperty("java.vm.name");
+        String arch = properties.getProperty("os.arch");
+        if ((arch.equals("amd64") || arch.equals("i386") || arch.equals("x86") ||
+             arch.equals("sparc") || arch.equals("sparcv9")) &&
+            (name.contains("Client") || name.contains("Server"))
+            ) {
+            platformOK = true;
+        } else {
+            System.err.println("Skipping tests for unsupported platform: "+Arrays.asList(vers, name, arch));
+        }
+        assumeTrue(platformOK);
+    }
+
+    String testName;
+    static int allPosTests, allNegTests;
+    int posTests, negTests;
+    @After
+    public void printCounts() {
+        if (verbosity >= 2 && (posTests | negTests) != 0) {
+            System.out.println();
+            if (posTests != 0)  System.out.println("=== "+testName+": "+posTests+" positive test cases run");
+            if (negTests != 0)  System.out.println("=== "+testName+": "+negTests+" negative test cases run");
+            allPosTests += posTests;
+            allNegTests += negTests;
+            posTests = negTests = 0;
+        }
+    }
+    void countTest(boolean positive) {
+        if (positive) ++posTests;
+        else          ++negTests;
+    }
+    void countTest() { countTest(true); }
+    void startTest(String name) {
+        if (testName != null)  printCounts();
+        if (verbosity >= 1)
+            System.out.println(name);
+        posTests = negTests = 0;
+        testName = name;
+    }
+
+    @BeforeClass
+    public static void setUpClass() throws Exception {
+        calledLog.clear();
+        calledLog.add(null);
+        nextArgVal = INITIAL_ARG_VAL;
+    }
+
+    @AfterClass
+    public static void tearDownClass() throws Exception {
+        int posTests = allPosTests, negTests = allNegTests;
+        if (verbosity >= 2 && (posTests | negTests) != 0) {
+            System.out.println();
+            if (posTests != 0)  System.out.println("=== "+posTests+" total positive test cases");
+            if (negTests != 0)  System.out.println("=== "+negTests+" total negative test cases");
+        }
+    }
+
+    static List<Object> calledLog = new ArrayList<Object>();
+    static Object logEntry(String name, Object... args) {
+        return Arrays.asList(name, Arrays.asList(args));
+    }
+    static Object called(String name, Object... args) {
+        Object entry = logEntry(name, args);
+        calledLog.add(entry);
+        return entry;
+    }
+    static void assertCalled(String name, Object... args) {
+        Object expected = logEntry(name, args);
+        Object actual   = calledLog.get(calledLog.size() - 1);
+        if (expected.equals(actual) && verbosity < 9)  return;
+        System.out.println("assertCalled "+name+":");
+        System.out.println("expected:   "+expected);
+        System.out.println("actual:     "+actual);
+        System.out.println("ex. types:  "+getClasses(expected));
+        System.out.println("act. types: "+getClasses(actual));
+        assertEquals("previous method call", expected, actual);
+    }
+    static void printCalled(MethodHandle target, String name, Object... args) {
+        if (verbosity >= 3)
+            System.out.println("calling MH="+target+" to "+name+Arrays.toString(args));
+    }
+
+    static Object castToWrapper(Object value, Class<?> dst) {
+        Object wrap = null;
+        if (value instanceof Number)
+            wrap = castToWrapperOrNull(((Number)value).longValue(), dst);
+        if (value instanceof Character)
+            wrap = castToWrapperOrNull((char)(Character)value, dst);
+        if (wrap != null)  return wrap;
+        return dst.cast(value);
+    }
+
+    static Object castToWrapperOrNull(long value, Class<?> dst) {
+        if (dst == int.class || dst == Integer.class)
+            return (int)(value);
+        if (dst == long.class || dst == Long.class)
+            return (long)(value);
+        if (dst == char.class || dst == Character.class)
+            return (char)(value);
+        if (dst == short.class || dst == Short.class)
+            return (short)(value);
+        if (dst == float.class || dst == Float.class)
+            return (float)(value);
+        if (dst == double.class || dst == Double.class)
+            return (double)(value);
+        if (dst == byte.class || dst == Byte.class)
+            return (byte)(value);
+        if (dst == boolean.class || dst == boolean.class)
+            return ((value % 29) & 1) == 0;
+        return null;
+    }
+
+    static final int ONE_MILLION = (1000*1000),  // first int value
+                     TEN_BILLION = (10*1000*1000*1000),  // scale factor to reach upper 32 bits
+                     INITIAL_ARG_VAL = ONE_MILLION << 1;  // <<1 makes space for sign bit;
+    static long nextArgVal;
+    static long nextArg(boolean moreBits) {
+        long val = nextArgVal++;
+        long sign = -(val & 1); // alternate signs
+        val >>= 1;
+        if (moreBits)
+            // Guarantee some bits in the high word.
+            // In any case keep the decimal representation simple-looking,
+            // with lots of zeroes, so as not to make the printed decimal
+            // strings unnecessarily noisy.
+            val += (val % ONE_MILLION) * TEN_BILLION;
+        return val ^ sign;
+    }
+    static int nextArg() {
+        // Produce a 32-bit result something like ONE_MILLION+(smallint).
+        // Example: 1_000_042.
+        return (int) nextArg(false);
+    }
+    static long nextArg(Class<?> kind) {
+        if (kind == long.class   || kind == Long.class ||
+            kind == double.class || kind == Double.class)
+            // produce a 64-bit result something like
+            // ((TEN_BILLION+1) * (ONE_MILLION+(smallint)))
+            // Example: 10_000_420_001_000_042.
+            return nextArg(true);
+        return (long) nextArg();
+    }
+
+    static Object randomArg(Class<?> param) {
+        Object wrap = castToWrapperOrNull(nextArg(param), param);
+        if (wrap != null) {
+            return wrap;
+        }
+//        import sun.dyn.util.Wrapper;
+//        Wrapper wrap = Wrapper.forBasicType(dst);
+//        if (wrap == Wrapper.OBJECT && Wrapper.isWrapperType(dst))
+//            wrap = Wrapper.forWrapperType(dst);
+//        if (wrap != Wrapper.OBJECT)
+//            return wrap.wrap(nextArg++);
+        if (param.isInterface()) {
+            for (Class<?> c : param.getClasses()) {
+                if (param.isAssignableFrom(c) && !c.isInterface())
+                    { param = c; break; }
+            }
+        }
+        if (param.isInterface() || param.isAssignableFrom(String.class))
+            return "#"+nextArg();
+        else
+            try {
+                return param.newInstance();
+            } catch (InstantiationException ex) {
+            } catch (IllegalAccessException ex) {
+            }
+        return null;  // random class not Object, String, Integer, etc.
+    }
+    static Object[] randomArgs(Class<?>... params) {
+        Object[] args = new Object[params.length];
+        for (int i = 0; i < args.length; i++)
+            args[i] = randomArg(params[i]);
+        return args;
+    }
+    static Object[] randomArgs(int nargs, Class<?> param) {
+        Object[] args = new Object[nargs];
+        for (int i = 0; i < args.length; i++)
+            args[i] = randomArg(param);
+        return args;
+    }
+
+    static final Object ANON_OBJ = new Object();
+    static Object zeroArg(Class<?> param) {
+        Object x = castToWrapperOrNull(0L, param);
+        if (x != null)  return x;
+        if (param.isInterface() || param.isAssignableFrom(String.class))  return "\"\"";
+        if (param == Object.class)  return ANON_OBJ;
+        if (param.getComponentType() != null)  return Array.newInstance(param.getComponentType(), 0);
+        return null;
+    }
+    static Object[] zeroArgs(Class<?>... params) {
+        Object[] args = new Object[params.length];
+        for (int i = 0; i < args.length; i++)
+            args[i] = zeroArg(params[i]);
+        return args;
+    }
+    static Object[] zeroArgs(List<Class<?>> params) {
+        return zeroArgs(params.toArray(new Class<?>[0]));
+    }
+
+    static <T, E extends T> T[] array(Class<T[]> atype, E... a) {
+        return Arrays.copyOf(a, a.length, atype);
+    }
+    static <T> T[] cat(T[] a, T... b) {
+        int alen = a.length, blen = b.length;
+        if (blen == 0)  return a;
+        T[] c = Arrays.copyOf(a, alen + blen);
+        System.arraycopy(b, 0, c, alen, blen);
+        return c;
+    }
+    static Integer[] boxAll(int... vx) {
+        Integer[] res = new Integer[vx.length];
+        for (int i = 0; i < res.length; i++) {
+            res[i] = vx[i];
+        }
+        return res;
+    }
+    static Object getClasses(Object x) {
+        if (x == null)  return x;
+        if (x instanceof String)  return x;  // keep the name
+        if (x instanceof List) {
+            // recursively report classes of the list elements
+            Object[] xa = ((List)x).toArray();
+            for (int i = 0; i < xa.length; i++)
+                xa[i] = getClasses(xa[i]);
+            return Arrays.asList(xa);
+        }
+        return x.getClass().getSimpleName();
+    }
+
+    static MethodHandle changeArgTypes(MethodHandle target, Class<?> argType) {
+        return changeArgTypes(target, 0, 999, argType);
+    }
+    static MethodHandle changeArgTypes(MethodHandle target,
+            int beg, int end, Class<?> argType) {
+        MethodType targetType = target.type();
+        end = Math.min(end, targetType.parameterCount());
+        ArrayList<Class<?>> argTypes = new ArrayList<Class<?>>(targetType.parameterList());
+        Collections.fill(argTypes.subList(beg, end), argType);
+        MethodType ttype2 = MethodType.methodType(targetType.returnType(), argTypes);
+        return MethodHandles.convertArguments(target, ttype2);
+    }
+
+    // This lookup is good for all members in and under InvokeGenericTest.
+    static final Lookup LOOKUP = MethodHandles.lookup();
+
+    Map<List<Class<?>>, MethodHandle> CALLABLES = new HashMap<List<Class<?>>, MethodHandle>();
+    MethodHandle callable(List<Class<?>> params) {
+        MethodHandle mh = CALLABLES.get(params);
+        if (mh == null) {
+            mh = collectArguments(collector_MH, methodType(Object.class, params));
+            CALLABLES.put(params, mh);
+        }
+        return mh;
+    }
+    MethodHandle callable(Class<?>... params) {
+        return callable(Arrays.asList(params));
+    }
+    private static Object collector(Object... args) {
+        return Arrays.asList(args);
+    }
+    private static final MethodHandle collector_MH;
+    static {
+        try {
+            collector_MH
+                = LOOKUP.findStatic(LOOKUP.lookupClass(),
+                                    "collector",
+                                    methodType(Object.class, Object[].class));
+        } catch (NoAccessException ex) {
+            throw new RuntimeException(ex);
+        }
+    }
+
+    @Test
+    public void testSimple() throws Throwable {
+        startTest("testSimple");
+        countTest();
+        String[] args = { "one", "two" };
+        MethodHandle mh = callable(Object.class, String.class);
+        Object res; List resl;
+        res = resl = (List) mh.<List>invokeGeneric((String)args[0], (Object)args[1]);
+        //System.out.println(res);
+        assertEquals(Arrays.asList(args), res);
+    }
+
+    @Test
+    public void testWrongArgumentCount() throws Throwable {
+        startTest("testWrongArgumentCount");
+        for (int i = 0; i <= 10; i++) {
+            testWrongArgumentCount(Collections.<Class<?>>nCopies(i, Integer.class));
+            if (i <= 4) {
+                testWrongArgumentCount(Collections.<Class<?>>nCopies(i, int.class));
+                testWrongArgumentCount(Collections.<Class<?>>nCopies(i, long.class));
+            }
+        }
+    }
+    public void testWrongArgumentCount(List<Class<?>> params) throws Throwable {
+        int max = params.size();
+        for (int i = 0; i < max; i++) {
+            List<Class<?>> params2 = params.subList(0, i);
+            for (int k = 0; k <= 2; k++) {
+                if (k == 1)  params  = methodType(Object.class,  params).generic().parameterList();
+                if (k == 2)  params2 = methodType(Object.class, params2).generic().parameterList();
+                testWrongArgumentCount(params, params2);
+                testWrongArgumentCount(params2, params);
+            }
+        }
+    }
+    public void testWrongArgumentCount(List<Class<?>> expect, List<Class<?>> observe) throws Throwable {
+        countTest(false);
+        if (expect.equals(observe))
+            assert(false);
+        MethodHandle target = callable(expect);
+        Object[] args = zeroArgs(observe);
+        Object junk;
+        try {
+            switch (args.length) {
+            case 0:
+                junk = target.invokeGeneric(); break;
+            case 1:
+                junk = target.invokeGeneric(args[0]); break;
+            case 2:
+                junk = target.invokeGeneric(args[0], args[1]); break;
+            case 3:
+                junk = target.invokeGeneric(args[0], args[1], args[2]); break;
+            case 4:
+                junk = target.invokeGeneric(args[0], args[1], args[2], args[3]); break;
+            default:
+                junk = MethodHandles.invokeVarargs(target, args); break;
+            }
+        } catch (WrongMethodTypeException ex) {
+            return;
+        } catch (Exception ex) {
+            throw new RuntimeException("wrong exception calling "+target+target.type()+" on "+Arrays.asList(args)+" : "+ex);
+        }
+        throw new RuntimeException("bad success calling "+target+target.type()+" on "+Arrays.asList(args));
+    }
+
+    /** Make a list of all combinations of the given types, with the given arities.
+     *  A void return type is possible iff the first type is void.class.
+     */
+    static List<MethodType> allMethodTypes(int minargc, int maxargc, Class<?>... types) {
+        ArrayList<MethodType> result = new ArrayList<MethodType>();
+        if (types.length > 0) {
+            ArrayList<MethodType> argcTypes = new ArrayList<MethodType>();
+            // build arity-zero types first
+            for (Class<?> rtype : types) {
+                argcTypes.add(MethodType.methodType(rtype));
+            }
+            if (types[0] == void.class)
+                // void is not an argument type
+                types = Arrays.copyOfRange(types, 1, types.length);
+            for (int argc = 0; argc <= maxargc; argc++) {
+                if (argc >= minargc)
+                    result.addAll(argcTypes);
+                if (argc >= maxargc)
+                    break;
+                ArrayList<MethodType> prevTypes = argcTypes;
+                argcTypes = new ArrayList<MethodType>();
+                for (MethodType prevType : prevTypes) {
+                    for (Class<?> ptype : types) {
+                        argcTypes.add(prevType.insertParameterTypes(argc, ptype));
+                    }
+                }
+            }
+        }
+        return Collections.unmodifiableList(result);
+    }
+    static List<MethodType> allMethodTypes(int argc, Class<?>... types) {
+        return allMethodTypes(argc, argc, types);
+    }
+
+    interface RandomInterface { }
+
+    MethodHandle toString_MH;
+
+    @Test
+    public void testReferenceConversions() throws Throwable {
+        startTest("testReferenceConversions");
+        toString_MH = LOOKUP.
+            findVirtual(Object.class, "toString", MethodType.methodType(String.class));
+        String[] args = { "one", "two" };
+        for (MethodType type : allMethodTypes(2, Object.class, String.class, RandomInterface.class)) {
+            testReferenceConversions(type, args);
+        }
+    }
+    public void testReferenceConversions(MethodType type, Object... args) throws Throwable {
+        countTest();
+        if (verbosity > 3)  System.out.println("target type: "+type);
+        MethodHandle mh = callable(type.parameterList());
+        MethodHandle tsdrop = MethodHandles.dropArguments(toString_MH, 1, type.parameterList());
+        mh = MethodHandles.foldArguments(tsdrop, mh);
+        mh = mh.asType(type);
+        Object res = mh.invokeGeneric((String)args[0], (Object)args[1]);
+        //System.out.println(res);
+        assertEquals(Arrays.asList(args).toString(), res);
+    }
+
+
+    @Test @Ignore("known failure pending 6939861")
+    public void testBoxConversions() throws Throwable {
+        startTest("testBoxConversions");
+        countTest();
+        Integer[] args = { 1, 2 };
+        MethodHandle mh = callable(Object.class, int.class);
+        Object res; List resl;
+        res = resl = (List) mh.<List>invokeGeneric((int)args[0], (Object)args[1]);
+        //System.out.println(res);
+        assertEquals(Arrays.asList(args), res);
+    }
+
+}
--- a/test/java/dyn/MethodHandlesTest.java	Tue Sep 14 01:42:03 2010 -0700
+++ b/test/java/dyn/MethodHandlesTest.java	Sat Oct 30 21:02:30 2010 -0700
@@ -1472,7 +1472,7 @@
         if (pos != 0)  return;  // can fold only at pos=0 for now
         countTest();
         MethodHandle target = ValueConversions.varargsList(1 + nargs);
-        MethodHandle combine = ValueConversions.varargsList(fold);
+        MethodHandle combine = ValueConversions.varargsList(fold).asType(MethodType.genericMethodType(fold));
         List<Object> argsToPass = Arrays.asList(randomArgs(nargs, Object.class));
         if (verbosity >= 3)
             System.out.println("fold "+target+" with "+combine);