/*
* Copyright (c) 2008, 2009, 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
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*/
package sun.dyn;
import sun.dyn.util.VerifyType;
import sun.dyn.util.Wrapper;
import java.dyn.*;
import java.util.Arrays;
import static sun.dyn.MethodHandleNatives.Constants.*;
import static sun.dyn.MemberName.newIllegalArgumentException;
/**
* This method handle performs simple conversion or checking of a single argument.
* @author jrose
*/
public 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);
if (MethodHandleNatives.JVM_SUPPORT) {
// 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);
}
private static final Access IMPL_TOKEN = Access.getToken();
// 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?
*/
public 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?
*/
public 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 token access check
* @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
*/
public static MethodHandle makePairwiseConvert(Access token,
MethodType newType, MethodHandle target) {
Access.check(token);
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(token, midType, adapter, i, dst);
} else {
adapter = makeBoxArgument(token, 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(token, 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(token, midType, adapter, i, dst);
}
}
assert(adapter != null);
assert(adapter.type() == midType);
}
if (adapter.type() != newType) {
// Only trivial conversions remain.
adapter = makeRetypeOnly(IMPL_TOKEN, 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 token access check
* @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
*/
public static MethodHandle makePermutation(Access token,
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(token, 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? */
public 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.
*/
public 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.
*/
public static MethodHandle makeRetypeOnly(Access token,
MethodType newType, MethodHandle target) {
return makeRetype(token, newType, target, false);
}
public static MethodHandle makeRetypeRaw(Access token,
MethodType newType, MethodHandle target) {
return makeRetype(token, newType, target, true);
}
static MethodHandle makeRetype(Access token,
MethodType newType, MethodHandle target, boolean raw) {
Access.check(token);
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));
}
/** Can a checkcast adapter validly convert the target to newType?
* The JVM supports all kind of reference casts, even silly ones.
*/
public 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? */
public 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.
*/
public static MethodHandle makeCheckCast(Access token,
MethodType newType, MethodHandle target,
int arg, Class<?> castType) {
Access.check(token);
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.
*/
public 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? */
public 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.
*/
public static MethodHandle makePrimCast(Access token,
MethodType newType, MethodHandle target,
int arg, Class<?> convType) {
Access.check(token);
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.
*/
public 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? */
public 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.
*/
public static MethodHandle makeUnboxArgument(Access token,
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(token, newType, adapter, arg, boxType);
}
/** Can an primitive boxing adapter validly convert src to dst? */
public 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.
*/
public static MethodHandle makeBoxArgument(Access token,
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? */
public 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.
*/
public static MethodHandle makeDropArguments(Access token,
MethodType newType, MethodHandle target,
int dropArgPos, int dropArgCount) {
Access.check(token);
if (dropArgCount == 0)
return makeRetypeOnly(IMPL_TOKEN, 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? */
public 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.
*/
public static MethodHandle makeDupArguments(Access token,
MethodType newType, MethodHandle target,
int dupArgPos, int dupArgCount) {
Access.check(token);
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? */
public 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.
*/
public static MethodHandle makeSwapArguments(Access token,
MethodType newType, MethodHandle target,
int swapArg1, int swapArg2) {
Access.check(token);
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? */
public 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.
*/
public static MethodHandle makeRotateArguments(Access token,
MethodType newType, MethodHandle target,
int firstArg, int argCount, int rotateBy) {
Access.check(token);
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? */
public 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. */
public static MethodHandle makeSpreadArguments(Access token,
MethodType newType, MethodHandle target,
Class<?> spreadArgType, int spreadArgPos, int spreadArgCount) {
Access.check(token);
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 nonAdapter((MethodHandle)vmtarget).toString();
}
private static MethodHandle nonAdapter(MethodHandle mh) {
while (mh instanceof AdapterMethodHandle) {
mh = (MethodHandle) mh.vmtarget;
}
return mh;
}
}