--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/dyn/AdapterMethodHandle.java Fri Mar 18 00:03:24 2011 -0700
@@ -0,0 +1,943 @@
+/*
+ * Copyright (c) 2008, 2011, 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 java.dyn;
+
+import sun.dyn.util.VerifyType;
+import sun.dyn.util.Wrapper;
+import java.util.Arrays;
+import static java.dyn.MethodHandleNatives.Constants.*;
+import static java.dyn.MethodHandleStatics.*;
+
+/**
+ * This method handle performs simple conversion or checking of a single argument.
+ * @author jrose
+ */
+class AdapterMethodHandle extends BoundMethodHandle {
+
+ //MethodHandle vmtarget; // next AMH or BMH in chain or final DMH
+ //Object argument; // parameter to the conversion if needed
+ //int vmargslot; // which argument slot is affected
+ private final int conversion; // the type of conversion: RETYPE_ONLY, etc.
+
+ // Constructors in this class *must* be package scoped or private.
+ private AdapterMethodHandle(MethodHandle target, MethodType newType,
+ long conv, Object convArg) {
+ super(newType, convArg, newType.parameterSlotDepth(1+convArgPos(conv)));
+ this.conversion = convCode(conv);
+ // JVM might update VM-specific bits of conversion (ignore)
+ MethodHandleNatives.init(this, target, convArgPos(conv));
+ }
+ private AdapterMethodHandle(MethodHandle target, MethodType newType,
+ long conv) {
+ this(target, newType, conv, null);
+ }
+
+ // TO DO: When adapting another MH with a null conversion, clone
+ // the target and change its type, instead of adding another layer.
+
+ /** Can a JVM-level adapter directly implement the proposed
+ * argument conversions, as if by MethodHandles.convertArguments?
+ */
+ static boolean canPairwiseConvert(MethodType newType, MethodType oldType) {
+ // same number of args, of course
+ int len = newType.parameterCount();
+ if (len != oldType.parameterCount())
+ return false;
+
+ // Check return type. (Not much can be done with it.)
+ Class<?> exp = newType.returnType();
+ Class<?> ret = oldType.returnType();
+ if (!VerifyType.isNullConversion(ret, exp))
+ return false;
+
+ // Check args pairwise.
+ for (int i = 0; i < len; i++) {
+ Class<?> src = newType.parameterType(i); // source type
+ Class<?> dst = oldType.parameterType(i); // destination type
+ if (!canConvertArgument(src, dst))
+ return false;
+ }
+
+ return true;
+ }
+
+ /** Can a JVM-level adapter directly implement the proposed
+ * argument conversion, as if by MethodHandles.convertArguments?
+ */
+ static boolean canConvertArgument(Class<?> src, Class<?> dst) {
+ // ? Retool this logic to use RETYPE_ONLY, CHECK_CAST, etc., as opcodes,
+ // so we don't need to repeat so much decision making.
+ if (VerifyType.isNullConversion(src, dst)) {
+ return true;
+ } else if (src.isPrimitive()) {
+ if (dst.isPrimitive())
+ return canPrimCast(src, dst);
+ else
+ return canBoxArgument(src, dst);
+ } else {
+ if (dst.isPrimitive())
+ return canUnboxArgument(src, dst);
+ else
+ return true; // any two refs can be interconverted
+ }
+ }
+
+ /**
+ * Create a JVM-level adapter method handle to conform the given method
+ * handle to the similar newType, using only pairwise argument conversions.
+ * For each argument, convert incoming argument to the exact type needed.
+ * Only null conversions are allowed on the return value (until
+ * the JVM supports ricochet adapters).
+ * The argument conversions allowed are casting, unboxing,
+ * integral widening or narrowing, and floating point widening or narrowing.
+ * @param newType required call type
+ * @param target original method handle
+ * @return an adapter to the original handle with the desired new type,
+ * or the original target if the types are already identical
+ * or null if the adaptation cannot be made
+ */
+ static MethodHandle makePairwiseConvert(MethodType newType, MethodHandle target) {
+ MethodType oldType = target.type();
+ if (newType == oldType) return target;
+
+ if (!canPairwiseConvert(newType, oldType))
+ return null;
+ // (after this point, it is an assertion error to fail to convert)
+
+ // Find last non-trivial conversion (if any).
+ int lastConv = newType.parameterCount()-1;
+ while (lastConv >= 0) {
+ Class<?> src = newType.parameterType(lastConv); // source type
+ Class<?> dst = oldType.parameterType(lastConv); // destination type
+ if (VerifyType.isNullConversion(src, dst)) {
+ --lastConv;
+ } else {
+ break;
+ }
+ }
+ // Now build a chain of one or more adapters.
+ MethodHandle adapter = target;
+ MethodType midType = oldType.changeReturnType(newType.returnType());
+ for (int i = 0; i <= lastConv; i++) {
+ Class<?> src = newType.parameterType(i); // source type
+ Class<?> dst = midType.parameterType(i); // destination type
+ if (VerifyType.isNullConversion(src, dst)) {
+ // do nothing: difference is trivial
+ continue;
+ }
+ // Work the current type backward toward the desired caller type:
+ if (i != lastConv) {
+ midType = midType.changeParameterType(i, src);
+ } else {
+ // When doing the last (or only) real conversion,
+ // force all remaining null conversions to happen also.
+ assert(VerifyType.isNullConversion(newType, midType.changeParameterType(i, src)));
+ midType = newType;
+ }
+
+ // Tricky case analysis follows.
+ // It parallels canConvertArgument() above.
+ if (src.isPrimitive()) {
+ if (dst.isPrimitive()) {
+ adapter = makePrimCast(midType, adapter, i, dst);
+ } else {
+ adapter = makeBoxArgument(midType, adapter, i, dst);
+ }
+ } else {
+ if (dst.isPrimitive()) {
+ // Caller has boxed a primitive. Unbox it for the target.
+ // The box type must correspond exactly to the primitive type.
+ // This is simpler than the powerful set of widening
+ // conversions supported by reflect.Method.invoke.
+ // Those conversions require a big nest of if/then/else logic,
+ // which we prefer to make a user responsibility.
+ adapter = makeUnboxArgument(midType, adapter, i, dst);
+ } else {
+ // Simple reference conversion.
+ // Note: Do not check for a class hierarchy relation
+ // between src and dst. In all cases a 'null' argument
+ // will pass the cast conversion.
+ adapter = makeCheckCast(midType, adapter, i, dst);
+ }
+ }
+ assert(adapter != null);
+ assert(adapter.type() == midType);
+ }
+ if (adapter.type() != newType) {
+ // Only trivial conversions remain.
+ adapter = makeRetypeOnly(newType, adapter);
+ assert(adapter != null);
+ // Actually, that's because there were no non-trivial ones:
+ assert(lastConv == -1);
+ }
+ assert(adapter.type() == newType);
+ return adapter;
+ }
+
+ /**
+ * Create a JVM-level adapter method handle to permute the arguments
+ * of the given method.
+ * @param newType required call type
+ * @param target original method handle
+ * @param argumentMap for each target argument, position of its source in newType
+ * @return an adapter to the original handle with the desired new type,
+ * or the original target if the types are already identical
+ * and the permutation is null
+ * @throws IllegalArgumentException if the adaptation cannot be made
+ * directly by a JVM-level adapter, without help from Java code
+ */
+ static MethodHandle makePermutation(MethodType newType, MethodHandle target,
+ int[] argumentMap) {
+ MethodType oldType = target.type();
+ boolean nullPermutation = true;
+ for (int i = 0; i < argumentMap.length; i++) {
+ int pos = argumentMap[i];
+ if (pos != i)
+ nullPermutation = false;
+ if (pos < 0 || pos >= newType.parameterCount()) {
+ argumentMap = new int[0]; break;
+ }
+ }
+ if (argumentMap.length != oldType.parameterCount())
+ throw newIllegalArgumentException("bad permutation: "+Arrays.toString(argumentMap));
+ if (nullPermutation) {
+ MethodHandle res = makePairwiseConvert(newType, target);
+ // well, that was easy
+ if (res == null)
+ throw newIllegalArgumentException("cannot convert pairwise: "+newType);
+ return res;
+ }
+
+ // Check return type. (Not much can be done with it.)
+ Class<?> exp = newType.returnType();
+ Class<?> ret = oldType.returnType();
+ if (!VerifyType.isNullConversion(ret, exp))
+ throw newIllegalArgumentException("bad return conversion for "+newType);
+
+ // See if the argument types match up.
+ for (int i = 0; i < argumentMap.length; i++) {
+ int j = argumentMap[i];
+ Class<?> src = newType.parameterType(j);
+ Class<?> dst = oldType.parameterType(i);
+ if (!VerifyType.isNullConversion(src, dst))
+ throw newIllegalArgumentException("bad argument #"+j+" conversion for "+newType);
+ }
+
+ // Now figure out a nice mix of SWAP, ROT, DUP, and DROP adapters.
+ // A workable greedy algorithm is as follows:
+ // Drop unused outgoing arguments (right to left: shallowest first).
+ // Duplicate doubly-used outgoing arguments (left to right: deepest first).
+ // Then the remaining problem is a true argument permutation.
+ // Marshal the outgoing arguments as required from left to right.
+ // That is, find the deepest outgoing stack position that does not yet
+ // have the correct argument value, and correct at least that position
+ // by swapping or rotating in the misplaced value (from a shallower place).
+ // If the misplaced value is followed by one or more consecutive values
+ // (also misplaced) issue a rotation which brings as many as possible
+ // into position. Otherwise make progress with either a swap or a
+ // rotation. Prefer the swap as cheaper, but do not use it if it
+ // breaks a slot pair. Prefer the rotation over the swap if it would
+ // preserve more consecutive values shallower than the target position.
+ // When more than one rotation will work (because the required value
+ // is already adjacent to the target position), then use a rotation
+ // which moves the old value in the target position adjacent to
+ // one of its consecutive values. Also, prefer shorter rotation
+ // spans, since they use fewer memory cycles for shuffling.
+
+ throw new UnsupportedOperationException("NYI");
+ }
+
+ private static byte basicType(Class<?> type) {
+ if (type == null) return T_VOID;
+ switch (Wrapper.forBasicType(type)) {
+ case BOOLEAN: return T_BOOLEAN;
+ case CHAR: return T_CHAR;
+ case FLOAT: return T_FLOAT;
+ case DOUBLE: return T_DOUBLE;
+ case BYTE: return T_BYTE;
+ case SHORT: return T_SHORT;
+ case INT: return T_INT;
+ case LONG: return T_LONG;
+ case OBJECT: return T_OBJECT;
+ case VOID: return T_VOID;
+ }
+ return 99; // T_ILLEGAL or some such
+ }
+
+ /** Number of stack slots for the given type.
+ * Two for T_DOUBLE and T_FLOAT, one for the rest.
+ */
+ private static int type2size(int type) {
+ assert(type >= T_BOOLEAN && type <= T_OBJECT);
+ return (type == T_LONG || type == T_DOUBLE) ? 2 : 1;
+ }
+ private static int type2size(Class<?> type) {
+ return type2size(basicType(type));
+ }
+
+ /** The given stackMove is the number of slots pushed.
+ * It might be negative. Scale it (multiply) by the
+ * VM's notion of how an address changes with a push,
+ * to get the raw SP change for stackMove.
+ * Then shift and mask it into the correct field.
+ */
+ private static long insertStackMove(int stackMove) {
+ // following variable must be long to avoid sign extension after '<<'
+ long spChange = stackMove * MethodHandleNatives.JVM_STACK_MOVE_UNIT;
+ return (spChange & CONV_STACK_MOVE_MASK) << CONV_STACK_MOVE_SHIFT;
+ }
+
+ /** Construct an adapter conversion descriptor for a single-argument conversion. */
+ private static long makeConv(int convOp, int argnum, int src, int dest) {
+ assert(src == (src & 0xF));
+ assert(dest == (dest & 0xF));
+ assert(convOp >= OP_CHECK_CAST && convOp <= OP_PRIM_TO_REF);
+ int stackMove = type2size(dest) - type2size(src);
+ return ((long) argnum << 32 |
+ (long) convOp << CONV_OP_SHIFT |
+ (int) src << CONV_SRC_TYPE_SHIFT |
+ (int) dest << CONV_DEST_TYPE_SHIFT |
+ insertStackMove(stackMove)
+ );
+ }
+ private static long makeConv(int convOp, int argnum, int stackMove) {
+ assert(convOp >= OP_DUP_ARGS && convOp <= OP_SPREAD_ARGS);
+ byte src = 0, dest = 0;
+ if (convOp >= OP_COLLECT_ARGS && convOp <= OP_SPREAD_ARGS)
+ src = dest = T_OBJECT;
+ return ((long) argnum << 32 |
+ (long) convOp << CONV_OP_SHIFT |
+ (int) src << CONV_SRC_TYPE_SHIFT |
+ (int) dest << CONV_DEST_TYPE_SHIFT |
+ insertStackMove(stackMove)
+ );
+ }
+ private static long makeSwapConv(int convOp, int srcArg, byte type, int destSlot) {
+ assert(convOp >= OP_SWAP_ARGS && convOp <= OP_ROT_ARGS);
+ return ((long) srcArg << 32 |
+ (long) convOp << CONV_OP_SHIFT |
+ (int) type << CONV_SRC_TYPE_SHIFT |
+ (int) type << CONV_DEST_TYPE_SHIFT |
+ (int) destSlot << CONV_VMINFO_SHIFT
+ );
+ }
+ private static long makeConv(int convOp) {
+ assert(convOp == OP_RETYPE_ONLY || convOp == OP_RETYPE_RAW);
+ return ((long)-1 << 32) | (convOp << CONV_OP_SHIFT); // stackMove, src, dst all zero
+ }
+ private static int convCode(long conv) {
+ return (int)conv;
+ }
+ private static int convArgPos(long conv) {
+ return (int)(conv >>> 32);
+ }
+ private static boolean convOpSupported(int convOp) {
+ assert(convOp >= 0 && convOp <= CONV_OP_LIMIT);
+ return ((1<<convOp) & MethodHandleNatives.CONV_OP_IMPLEMENTED_MASK) != 0;
+ }
+
+ /** One of OP_RETYPE_ONLY, etc. */
+ int conversionOp() { return (conversion & CONV_OP_MASK) >> CONV_OP_SHIFT; }
+
+ /* Return one plus the position of the first non-trivial difference
+ * between the given types. This is not a symmetric operation;
+ * we are considering adapting the targetType to adapterType.
+ * Trivial differences are those which could be ignored by the JVM
+ * without subverting the verifier. Otherwise, adaptable differences
+ * are ones for which we could create an adapter to make the type change.
+ * Return zero if there are no differences (other than trivial ones).
+ * Return 1+N if N is the only adaptable argument difference.
+ * Return the -2-N where N is the first of several adaptable
+ * argument differences.
+ * Return -1 if there there are differences which are not adaptable.
+ */
+ private static int diffTypes(MethodType adapterType,
+ MethodType targetType,
+ boolean raw) {
+ int diff;
+ diff = diffReturnTypes(adapterType, targetType, raw);
+ if (diff != 0) return diff;
+ int nargs = adapterType.parameterCount();
+ if (nargs != targetType.parameterCount())
+ return -1;
+ diff = diffParamTypes(adapterType, 0, targetType, 0, nargs, raw);
+ //System.out.println("diff "+adapterType);
+ //System.out.println(" "+diff+" "+targetType);
+ return diff;
+ }
+ private static int diffReturnTypes(MethodType adapterType,
+ MethodType targetType,
+ boolean raw) {
+ Class<?> src = targetType.returnType();
+ Class<?> dst = adapterType.returnType();
+ if ((!raw
+ ? VerifyType.canPassUnchecked(src, dst)
+ : VerifyType.canPassRaw(src, dst)
+ ) > 0)
+ return 0; // no significant difference
+ if (raw && !src.isPrimitive() && !dst.isPrimitive())
+ return 0; // can force a reference return (very carefully!)
+ //if (false) return 1; // never adaptable!
+ return -1; // some significant difference
+ }
+ private static int diffParamTypes(MethodType adapterType, int astart,
+ MethodType targetType, int tstart,
+ int nargs, boolean raw) {
+ assert(nargs >= 0);
+ int res = 0;
+ for (int i = 0; i < nargs; i++) {
+ Class<?> src = adapterType.parameterType(astart+i);
+ Class<?> dest = targetType.parameterType(tstart+i);
+ if ((!raw
+ ? VerifyType.canPassUnchecked(src, dest)
+ : VerifyType.canPassRaw(src, dest)
+ ) <= 0) {
+ // found a difference; is it the only one so far?
+ if (res != 0)
+ return -1-res; // return -2-i for prev. i
+ res = 1+i;
+ }
+ }
+ return res;
+ }
+
+ /** Can a retyping adapter (alone) validly convert the target to newType? */
+ static boolean canRetypeOnly(MethodType newType, MethodType targetType) {
+ return canRetype(newType, targetType, false);
+ }
+ /** Can a retyping adapter (alone) convert the target to newType?
+ * It is allowed to widen subword types and void to int, to make bitwise
+ * conversions between float/int and double/long, and to perform unchecked
+ * reference conversions on return. This last feature requires that the
+ * caller be trusted, and perform explicit cast conversions on return values.
+ */
+ static boolean canRetypeRaw(MethodType newType, MethodType targetType) {
+ return canRetype(newType, targetType, true);
+ }
+ static boolean canRetype(MethodType newType, MethodType targetType, boolean raw) {
+ if (!convOpSupported(raw ? OP_RETYPE_RAW : OP_RETYPE_ONLY)) return false;
+ int diff = diffTypes(newType, targetType, raw);
+ // %%% This assert is too strong. Factor diff into VerifyType and reconcile.
+ assert(raw || (diff == 0) == VerifyType.isNullConversion(newType, targetType));
+ return diff == 0;
+ }
+
+ /** Factory method: Performs no conversions; simply retypes the adapter.
+ * Allows unchecked argument conversions pairwise, if they are safe.
+ * Returns null if not possible.
+ */
+ static MethodHandle makeRetypeOnly(MethodType newType, MethodHandle target) {
+ return makeRetype(newType, target, false);
+ }
+ static MethodHandle makeRetypeRaw(MethodType newType, MethodHandle target) {
+ return makeRetype(newType, target, true);
+ }
+ static MethodHandle makeRetype(MethodType newType, MethodHandle target, boolean raw) {
+ MethodType oldType = target.type();
+ if (oldType == newType) return target;
+ if (!canRetype(newType, oldType, raw))
+ return null;
+ // TO DO: clone the target guy, whatever he is, with new type.
+ return new AdapterMethodHandle(target, newType, makeConv(raw ? OP_RETYPE_RAW : OP_RETYPE_ONLY));
+ }
+
+ static MethodHandle makeVarargsCollector(MethodHandle target, Class<?> arrayType) {
+ return new AsVarargsCollector(target, arrayType);
+ }
+
+ static class AsVarargsCollector extends AdapterMethodHandle {
+ final MethodHandle target;
+ final Class<?> arrayType;
+ MethodHandle cache;
+
+ AsVarargsCollector(MethodHandle target, Class<?> arrayType) {
+ super(target, target.type(), makeConv(OP_RETYPE_ONLY));
+ this.target = target;
+ this.arrayType = arrayType;
+ this.cache = target.asCollector(arrayType, 0);
+ }
+
+ @Override
+ public boolean isVarargsCollector() {
+ return true;
+ }
+
+ @Override
+ public MethodHandle asType(MethodType newType) {
+ MethodType type = this.type();
+ int collectArg = type.parameterCount() - 1;
+ int newArity = newType.parameterCount();
+ if (newArity == collectArg+1 &&
+ type.parameterType(collectArg).isAssignableFrom(newType.parameterType(collectArg))) {
+ // if arity and trailing parameter are compatible, do normal thing
+ return super.asType(newType);
+ }
+ // check cache
+ if (cache.type().parameterCount() == newArity)
+ return cache.asType(newType);
+ // build and cache a collector
+ int arrayLength = newArity - collectArg;
+ MethodHandle collector;
+ try {
+ collector = target.asCollector(arrayType, arrayLength);
+ } catch (IllegalArgumentException ex) {
+ throw new WrongMethodTypeException("cannot build collector");
+ }
+ cache = collector;
+ return collector.asType(newType);
+ }
+
+ @Override
+ public MethodHandle asVarargsCollector(Class<?> arrayType) {
+ MethodType type = this.type();
+ if (type.parameterType(type.parameterCount()-1) == arrayType)
+ return this;
+ return super.asVarargsCollector(arrayType);
+ }
+ }
+
+ /** Can a checkcast adapter validly convert the target to newType?
+ * The JVM supports all kind of reference casts, even silly ones.
+ */
+ static boolean canCheckCast(MethodType newType, MethodType targetType,
+ int arg, Class<?> castType) {
+ if (!convOpSupported(OP_CHECK_CAST)) return false;
+ Class<?> src = newType.parameterType(arg);
+ Class<?> dst = targetType.parameterType(arg);
+ if (!canCheckCast(src, castType)
+ || !VerifyType.isNullConversion(castType, dst))
+ return false;
+ int diff = diffTypes(newType, targetType, false);
+ return (diff == arg+1); // arg is sole non-trivial diff
+ }
+ /** Can an primitive conversion adapter validly convert src to dst? */
+ static boolean canCheckCast(Class<?> src, Class<?> dst) {
+ return (!src.isPrimitive() && !dst.isPrimitive());
+ }
+
+ /** Factory method: Forces a cast at the given argument.
+ * The castType is the target of the cast, and can be any type
+ * with a null conversion to the corresponding target parameter.
+ * Return null if this cannot be done.
+ */
+ static MethodHandle makeCheckCast(MethodType newType, MethodHandle target,
+ int arg, Class<?> castType) {
+ if (!canCheckCast(newType, target.type(), arg, castType))
+ return null;
+ long conv = makeConv(OP_CHECK_CAST, arg, T_OBJECT, T_OBJECT);
+ return new AdapterMethodHandle(target, newType, conv, castType);
+ }
+
+ /** Can an primitive conversion adapter validly convert the target to newType?
+ * The JVM currently supports all conversions except those between
+ * floating and integral types.
+ */
+ static boolean canPrimCast(MethodType newType, MethodType targetType,
+ int arg, Class<?> convType) {
+ if (!convOpSupported(OP_PRIM_TO_PRIM)) return false;
+ Class<?> src = newType.parameterType(arg);
+ Class<?> dst = targetType.parameterType(arg);
+ if (!canPrimCast(src, convType)
+ || !VerifyType.isNullConversion(convType, dst))
+ return false;
+ int diff = diffTypes(newType, targetType, false);
+ return (diff == arg+1); // arg is sole non-trivial diff
+ }
+ /** Can an primitive conversion adapter validly convert src to dst? */
+ static boolean canPrimCast(Class<?> src, Class<?> dst) {
+ if (src == dst || !src.isPrimitive() || !dst.isPrimitive()) {
+ return false;
+ } else if (Wrapper.forPrimitiveType(dst).isFloating()) {
+ // both must be floating types
+ return Wrapper.forPrimitiveType(src).isFloating();
+ } else {
+ // both are integral, and all combinations work fine
+ assert(Wrapper.forPrimitiveType(src).isIntegral() &&
+ Wrapper.forPrimitiveType(dst).isIntegral());
+ return true;
+ }
+ }
+
+ /** Factory method: Truncate the given argument with zero or sign extension,
+ * and/or convert between single and doubleword versions of integer or float.
+ * The convType is the target of the conversion, and can be any type
+ * with a null conversion to the corresponding target parameter.
+ * Return null if this cannot be done.
+ */
+ static MethodHandle makePrimCast(MethodType newType, MethodHandle target,
+ int arg, Class<?> convType) {
+ MethodType oldType = target.type();
+ if (!canPrimCast(newType, oldType, arg, convType))
+ return null;
+ Class<?> src = newType.parameterType(arg);
+ long conv = makeConv(OP_PRIM_TO_PRIM, arg, basicType(src), basicType(convType));
+ return new AdapterMethodHandle(target, newType, conv);
+ }
+
+ /** Can an unboxing conversion validly convert src to dst?
+ * The JVM currently supports all kinds of casting and unboxing.
+ * The convType is the unboxed type; it can be either a primitive or wrapper.
+ */
+ static boolean canUnboxArgument(MethodType newType, MethodType targetType,
+ int arg, Class<?> convType) {
+ if (!convOpSupported(OP_REF_TO_PRIM)) return false;
+ Class<?> src = newType.parameterType(arg);
+ Class<?> dst = targetType.parameterType(arg);
+ Class<?> boxType = Wrapper.asWrapperType(convType);
+ convType = Wrapper.asPrimitiveType(convType);
+ if (!canCheckCast(src, boxType)
+ || boxType == convType
+ || !VerifyType.isNullConversion(convType, dst))
+ return false;
+ int diff = diffTypes(newType, targetType, false);
+ return (diff == arg+1); // arg is sole non-trivial diff
+ }
+ /** Can an primitive unboxing adapter validly convert src to dst? */
+ static boolean canUnboxArgument(Class<?> src, Class<?> dst) {
+ return (!src.isPrimitive() && Wrapper.asPrimitiveType(dst).isPrimitive());
+ }
+
+ /** Factory method: Unbox the given argument.
+ * Return null if this cannot be done.
+ */
+ static MethodHandle makeUnboxArgument(MethodType newType, MethodHandle target,
+ int arg, Class<?> convType) {
+ MethodType oldType = target.type();
+ Class<?> src = newType.parameterType(arg);
+ Class<?> dst = oldType.parameterType(arg);
+ Class<?> boxType = Wrapper.asWrapperType(convType);
+ Class<?> primType = Wrapper.asPrimitiveType(convType);
+ if (!canUnboxArgument(newType, oldType, arg, convType))
+ return null;
+ MethodType castDone = newType;
+ if (!VerifyType.isNullConversion(src, boxType))
+ castDone = newType.changeParameterType(arg, boxType);
+ long conv = makeConv(OP_REF_TO_PRIM, arg, T_OBJECT, basicType(primType));
+ MethodHandle adapter = new AdapterMethodHandle(target, castDone, conv, boxType);
+ if (castDone == newType)
+ return adapter;
+ return makeCheckCast(newType, adapter, arg, boxType);
+ }
+
+ /** Can an primitive boxing adapter validly convert src to dst? */
+ static boolean canBoxArgument(Class<?> src, Class<?> dst) {
+ if (!convOpSupported(OP_PRIM_TO_REF)) return false;
+ throw new UnsupportedOperationException("NYI");
+ }
+
+ /** Factory method: Unbox the given argument.
+ * Return null if this cannot be done.
+ */
+ static MethodHandle makeBoxArgument(MethodType newType, MethodHandle target,
+ int arg, Class<?> convType) {
+ // this is difficult to do in the JVM because it must GC
+ return null;
+ }
+
+ /** Can an adapter simply drop arguments to convert the target to newType? */
+ static boolean canDropArguments(MethodType newType, MethodType targetType,
+ int dropArgPos, int dropArgCount) {
+ if (dropArgCount == 0)
+ return canRetypeOnly(newType, targetType);
+ if (!convOpSupported(OP_DROP_ARGS)) return false;
+ if (diffReturnTypes(newType, targetType, false) != 0)
+ return false;
+ int nptypes = newType.parameterCount();
+ // parameter types must be the same up to the drop point
+ if (dropArgPos != 0 && diffParamTypes(newType, 0, targetType, 0, dropArgPos, false) != 0)
+ return false;
+ int afterPos = dropArgPos + dropArgCount;
+ int afterCount = nptypes - afterPos;
+ if (dropArgPos < 0 || dropArgPos >= nptypes ||
+ dropArgCount < 1 || afterPos > nptypes ||
+ targetType.parameterCount() != nptypes - dropArgCount)
+ return false;
+ // parameter types after the drop point must also be the same
+ if (afterCount != 0 && diffParamTypes(newType, afterPos, targetType, dropArgPos, afterCount, false) != 0)
+ return false;
+ return true;
+ }
+
+ /** Factory method: Drop selected arguments.
+ * Allow unchecked retyping of remaining arguments, pairwise.
+ * Return null if this is not possible.
+ */
+ static MethodHandle makeDropArguments(MethodType newType, MethodHandle target,
+ int dropArgPos, int dropArgCount) {
+ if (dropArgCount == 0)
+ return makeRetypeOnly(newType, target);
+ if (!canDropArguments(newType, target.type(), dropArgPos, dropArgCount))
+ return null;
+ // in arglist: [0: ...keep1 | dpos: drop... | dpos+dcount: keep2... ]
+ // out arglist: [0: ...keep1 | dpos: keep2... ]
+ int keep2InPos = dropArgPos + dropArgCount;
+ int dropSlot = newType.parameterSlotDepth(keep2InPos);
+ int keep1InSlot = newType.parameterSlotDepth(dropArgPos);
+ int slotCount = keep1InSlot - dropSlot;
+ assert(slotCount >= dropArgCount);
+ assert(target.type().parameterSlotCount() + slotCount == newType.parameterSlotCount());
+ long conv = makeConv(OP_DROP_ARGS, dropArgPos + dropArgCount - 1, -slotCount);
+ return new AdapterMethodHandle(target, newType, conv);
+ }
+
+ /** Can an adapter duplicate an argument to convert the target to newType? */
+ static boolean canDupArguments(MethodType newType, MethodType targetType,
+ int dupArgPos, int dupArgCount) {
+ if (!convOpSupported(OP_DUP_ARGS)) return false;
+ if (diffReturnTypes(newType, targetType, false) != 0)
+ return false;
+ int nptypes = newType.parameterCount();
+ if (dupArgCount < 0 || dupArgPos + dupArgCount > nptypes)
+ return false;
+ if (targetType.parameterCount() != nptypes + dupArgCount)
+ return false;
+ // parameter types must be the same up to the duplicated arguments
+ if (diffParamTypes(newType, 0, targetType, 0, nptypes, false) != 0)
+ return false;
+ // duplicated types must be, well, duplicates
+ if (diffParamTypes(newType, dupArgPos, targetType, nptypes, dupArgCount, false) != 0)
+ return false;
+ return true;
+ }
+
+ /** Factory method: Duplicate the selected argument.
+ * Return null if this is not possible.
+ */
+ static MethodHandle makeDupArguments(MethodType newType, MethodHandle target,
+ int dupArgPos, int dupArgCount) {
+ if (!canDupArguments(newType, target.type(), dupArgPos, dupArgCount))
+ return null;
+ if (dupArgCount == 0)
+ return target;
+ // in arglist: [0: ...keep1 | dpos: dup... | dpos+dcount: keep2... ]
+ // out arglist: [0: ...keep1 | dpos: dup... | dpos+dcount: keep2... | dup... ]
+ int keep2InPos = dupArgPos + dupArgCount;
+ int dupSlot = newType.parameterSlotDepth(keep2InPos);
+ int keep1InSlot = newType.parameterSlotDepth(dupArgPos);
+ int slotCount = keep1InSlot - dupSlot;
+ assert(target.type().parameterSlotCount() - slotCount == newType.parameterSlotCount());
+ long conv = makeConv(OP_DUP_ARGS, dupArgPos + dupArgCount - 1, slotCount);
+ return new AdapterMethodHandle(target, newType, conv);
+ }
+
+ /** Can an adapter swap two arguments to convert the target to newType? */
+ static boolean canSwapArguments(MethodType newType, MethodType targetType,
+ int swapArg1, int swapArg2) {
+ if (!convOpSupported(OP_SWAP_ARGS)) return false;
+ if (diffReturnTypes(newType, targetType, false) != 0)
+ return false;
+ if (swapArg1 >= swapArg2) return false; // caller resp
+ int nptypes = newType.parameterCount();
+ if (targetType.parameterCount() != nptypes)
+ return false;
+ if (swapArg1 < 0 || swapArg2 >= nptypes)
+ return false;
+ if (diffParamTypes(newType, 0, targetType, 0, swapArg1, false) != 0)
+ return false;
+ if (diffParamTypes(newType, swapArg1, targetType, swapArg2, 1, false) != 0)
+ return false;
+ if (diffParamTypes(newType, swapArg1+1, targetType, swapArg1+1, swapArg2-swapArg1-1, false) != 0)
+ return false;
+ if (diffParamTypes(newType, swapArg2, targetType, swapArg1, 1, false) != 0)
+ return false;
+ if (diffParamTypes(newType, swapArg2+1, targetType, swapArg2+1, nptypes-swapArg2-1, false) != 0)
+ return false;
+ return true;
+ }
+
+ /** Factory method: Swap the selected arguments.
+ * Return null if this is not possible.
+ */
+ static MethodHandle makeSwapArguments(MethodType newType, MethodHandle target,
+ int swapArg1, int swapArg2) {
+ if (swapArg1 == swapArg2)
+ return target;
+ if (swapArg1 > swapArg2) { int t = swapArg1; swapArg1 = swapArg2; swapArg2 = t; }
+ if (!canSwapArguments(newType, target.type(), swapArg1, swapArg2))
+ return null;
+ Class<?> swapType = newType.parameterType(swapArg1);
+ // in arglist: [0: ...keep1 | pos1: a1 | pos1+1: keep2... | pos2: a2 | pos2+1: keep3... ]
+ // out arglist: [0: ...keep1 | pos1: a2 | pos1+1: keep2... | pos2: a1 | pos2+1: keep3... ]
+ int swapSlot2 = newType.parameterSlotDepth(swapArg2 + 1);
+ long conv = makeSwapConv(OP_SWAP_ARGS, swapArg1, basicType(swapType), swapSlot2);
+ return new AdapterMethodHandle(target, newType, conv);
+ }
+
+ static int positiveRotation(int argCount, int rotateBy) {
+ assert(argCount > 0);
+ if (rotateBy >= 0) {
+ if (rotateBy < argCount)
+ return rotateBy;
+ return rotateBy % argCount;
+ } else if (rotateBy >= -argCount) {
+ return rotateBy + argCount;
+ } else {
+ return (-1-((-1-rotateBy) % argCount)) + argCount;
+ }
+ }
+
+ final static int MAX_ARG_ROTATION = 1;
+
+ /** Can an adapter rotate arguments to convert the target to newType? */
+ static boolean canRotateArguments(MethodType newType, MethodType targetType,
+ int firstArg, int argCount, int rotateBy) {
+ if (!convOpSupported(OP_ROT_ARGS)) return false;
+ if (argCount <= 2) return false; // must be a swap, not a rotate
+ rotateBy = positiveRotation(argCount, rotateBy);
+ if (rotateBy == 0) return false; // no rotation
+ if (rotateBy > MAX_ARG_ROTATION && rotateBy < argCount - MAX_ARG_ROTATION)
+ return false; // too many argument positions
+ // Rotate incoming args right N to the out args, N in 1..(argCouunt-1).
+ if (diffReturnTypes(newType, targetType, false) != 0)
+ return false;
+ int nptypes = newType.parameterCount();
+ if (targetType.parameterCount() != nptypes)
+ return false;
+ if (firstArg < 0 || firstArg >= nptypes) return false;
+ int argLimit = firstArg + argCount;
+ if (argLimit > nptypes) return false;
+ if (diffParamTypes(newType, 0, targetType, 0, firstArg, false) != 0)
+ return false;
+ int newChunk1 = argCount - rotateBy, newChunk2 = rotateBy;
+ // swap new chunk1 with target chunk2
+ if (diffParamTypes(newType, firstArg, targetType, argLimit-newChunk1, newChunk1, false) != 0)
+ return false;
+ // swap new chunk2 with target chunk1
+ if (diffParamTypes(newType, firstArg+newChunk1, targetType, firstArg, newChunk2, false) != 0)
+ return false;
+ return true;
+ }
+
+ /** Factory method: Rotate the selected argument range.
+ * Return null if this is not possible.
+ */
+ static MethodHandle makeRotateArguments(MethodType newType, MethodHandle target,
+ int firstArg, int argCount, int rotateBy) {
+ rotateBy = positiveRotation(argCount, rotateBy);
+ if (!canRotateArguments(newType, target.type(), firstArg, argCount, rotateBy))
+ return null;
+ // Decide whether it should be done as a right or left rotation,
+ // on the JVM stack. Return the number of stack slots to rotate by,
+ // positive if right, negative if left.
+ int limit = firstArg + argCount;
+ int depth0 = newType.parameterSlotDepth(firstArg);
+ int depth1 = newType.parameterSlotDepth(limit-rotateBy);
+ int depth2 = newType.parameterSlotDepth(limit);
+ int chunk1Slots = depth0 - depth1; assert(chunk1Slots > 0);
+ int chunk2Slots = depth1 - depth2; assert(chunk2Slots > 0);
+ // From here on out, it assumes a single-argument shift.
+ assert(MAX_ARG_ROTATION == 1);
+ int srcArg, dstArg;
+ byte basicType;
+ if (chunk2Slots <= chunk1Slots) {
+ // Rotate right/down N (rotateBy = +N, N small, c2 small):
+ // in arglist: [0: ...keep1 | arg1: c1... | limit-N: c2 | limit: keep2... ]
+ // out arglist: [0: ...keep1 | arg1: c2 | arg1+N: c1... | limit: keep2... ]
+ srcArg = limit-1;
+ dstArg = firstArg;
+ basicType = basicType(newType.parameterType(srcArg));
+ assert(chunk2Slots == type2size(basicType));
+ } else {
+ // Rotate left/up N (rotateBy = -N, N small, c1 small):
+ // in arglist: [0: ...keep1 | arg1: c1 | arg1+N: c2... | limit: keep2... ]
+ // out arglist: [0: ...keep1 | arg1: c2 ... | limit-N: c1 | limit: keep2... ]
+ srcArg = firstArg;
+ dstArg = limit-1;
+ basicType = basicType(newType.parameterType(srcArg));
+ assert(chunk1Slots == type2size(basicType));
+ }
+ int dstSlot = newType.parameterSlotDepth(dstArg + 1);
+ long conv = makeSwapConv(OP_ROT_ARGS, srcArg, basicType, dstSlot);
+ return new AdapterMethodHandle(target, newType, conv);
+ }
+
+ /** Can an adapter spread an argument to convert the target to newType? */
+ static boolean canSpreadArguments(MethodType newType, MethodType targetType,
+ Class<?> spreadArgType, int spreadArgPos, int spreadArgCount) {
+ if (!convOpSupported(OP_SPREAD_ARGS)) return false;
+ if (diffReturnTypes(newType, targetType, false) != 0)
+ return false;
+ int nptypes = newType.parameterCount();
+ // parameter types must be the same up to the spread point
+ if (spreadArgPos != 0 && diffParamTypes(newType, 0, targetType, 0, spreadArgPos, false) != 0)
+ return false;
+ int afterPos = spreadArgPos + spreadArgCount;
+ int afterCount = nptypes - (spreadArgPos + 1);
+ if (spreadArgPos < 0 || spreadArgPos >= nptypes ||
+ spreadArgCount < 0 ||
+ targetType.parameterCount() != afterPos + afterCount)
+ return false;
+ // parameter types after the spread point must also be the same
+ if (afterCount != 0 && diffParamTypes(newType, spreadArgPos+1, targetType, afterPos, afterCount, false) != 0)
+ return false;
+ // match the array element type to the spread arg types
+ Class<?> rawSpreadArgType = newType.parameterType(spreadArgPos);
+ if (rawSpreadArgType != spreadArgType && !canCheckCast(rawSpreadArgType, spreadArgType))
+ return false;
+ for (int i = 0; i < spreadArgCount; i++) {
+ Class<?> src = VerifyType.spreadArgElementType(spreadArgType, i);
+ Class<?> dst = targetType.parameterType(spreadArgPos + i);
+ if (src == null || !VerifyType.isNullConversion(src, dst))
+ return false;
+ }
+ return true;
+ }
+
+
+ /** Factory method: Spread selected argument. */
+ static MethodHandle makeSpreadArguments(MethodType newType, MethodHandle target,
+ Class<?> spreadArgType, int spreadArgPos, int spreadArgCount) {
+ MethodType targetType = target.type();
+ if (!canSpreadArguments(newType, targetType, spreadArgType, spreadArgPos, spreadArgCount))
+ return null;
+ // in arglist: [0: ...keep1 | spos: spreadArg | spos+1: keep2... ]
+ // out arglist: [0: ...keep1 | spos: spread... | spos+scount: keep2... ]
+ int keep2OutPos = spreadArgPos + spreadArgCount;
+ int spreadSlot = targetType.parameterSlotDepth(keep2OutPos);
+ int keep1OutSlot = targetType.parameterSlotDepth(spreadArgPos);
+ int slotCount = keep1OutSlot - spreadSlot;
+ assert(spreadSlot == newType.parameterSlotDepth(spreadArgPos+1));
+ assert(slotCount >= spreadArgCount);
+ long conv = makeConv(OP_SPREAD_ARGS, spreadArgPos, slotCount-1);
+ MethodHandle res = new AdapterMethodHandle(target, newType, conv, spreadArgType);
+ assert(res.type().parameterType(spreadArgPos) == spreadArgType);
+ return res;
+ }
+
+ // TO DO: makeCollectArguments, makeFlyby, makeRicochet
+
+ @Override
+ public String toString() {
+ return getNameString(nonAdapter((MethodHandle)vmtarget), this);
+ }
+
+ private static MethodHandle nonAdapter(MethodHandle mh) {
+ while (mh instanceof AdapterMethodHandle) {
+ mh = (MethodHandle) mh.vmtarget;
+ }
+ return mh;
+ }
+}