JDK8/Java8源码在线阅读
/*
* Copyright (c) 2014, 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 java.lang.invoke;
import java.lang.ref.SoftReference;
import java.util.Arrays;
import static java.lang.invoke.LambdaForm.*;
import static java.lang.invoke.LambdaForm.BasicType.*;
import static java.lang.invoke.MethodHandleImpl.Intrinsic;
import java.util.Collections;
import java.util.concurrent.ConcurrentHashMap;
import sun.invoke.util.Wrapper;
/** Transforms on LFs.
* A lambda-form editor can derive new LFs from its base LF.
* The editor can cache derived LFs, which simplifies the reuse of their underlying bytecodes.
* To support this caching, a LF has an optional pointer to its editor.
*/
class LambdaFormEditor {
final LambdaForm lambdaForm;
private LambdaFormEditor(LambdaForm lambdaForm) {
this.lambdaForm = lambdaForm;
}
// Factory method.
static LambdaFormEditor lambdaFormEditor(LambdaForm lambdaForm) {
// TO DO: Consider placing intern logic here, to cut down on duplication.
// lambdaForm = findPreexistingEquivalent(lambdaForm)
return new LambdaFormEditor(lambdaForm);
}
/** A description of a cached transform, possibly associated with the result of the transform.
* The logical content is a sequence of byte values, starting with a Kind.ordinal value.
* The sequence is unterminated, ending with an indefinite number of zero bytes.
* Sequences that are simple (short enough and with small enough values) pack into a 64-bit long.
*/
private static final class Transform extends SoftReference<LambdaForm> {
final long packedBytes;
final byte[] fullBytes;
private enum Kind {
NO_KIND, // necessary because ordinal must be greater than zero
BIND_ARG, ADD_ARG, DUP_ARG,
SPREAD_ARGS,
FILTER_ARG, FILTER_RETURN, FILTER_RETURN_TO_ZERO,
COLLECT_ARGS, COLLECT_ARGS_TO_VOID, COLLECT_ARGS_TO_ARRAY,
FOLD_ARGS, FOLD_ARGS_TO_VOID,
PERMUTE_ARGS
//maybe add more for guard with test, catch exception, pointwise type conversions
}
private static final boolean STRESS_TEST = false; // turn on to disable most packing
private static final int
PACKED_BYTE_SIZE = (STRESS_TEST ? 2 : 4),
PACKED_BYTE_MASK = (1 << PACKED_BYTE_SIZE) - 1,
PACKED_BYTE_MAX_LENGTH = (STRESS_TEST ? 3 : 64 / PACKED_BYTE_SIZE);
private static long packedBytes(byte[] bytes) {
if (bytes.length > PACKED_BYTE_MAX_LENGTH) return 0;
long pb = 0;
int bitset = 0;
for (int i = 0; i < bytes.length; i++) {
int b = bytes[i] & 0xFF;
bitset |= b;
pb |= (long)b << (i * PACKED_BYTE_SIZE);
}
if (!inRange(bitset))
return 0;
return pb;
}
private static long packedBytes(int b0, int b1) {
assert(inRange(b0 | b1));
return ( (b0 << 0*PACKED_BYTE_SIZE)
| (b1 << 1*PACKED_BYTE_SIZE));
}
private static long packedBytes(int b0, int b1, int b2) {
assert(inRange(b0 | b1 | b2));
return ( (b0 << 0*PACKED_BYTE_SIZE)
| (b1 << 1*PACKED_BYTE_SIZE)
| (b2 << 2*PACKED_BYTE_SIZE));
}
private static long packedBytes(int b0, int b1, int b2, int b3) {
assert(inRange(b0 | b1 | b2 | b3));
return ( (b0 << 0*PACKED_BYTE_SIZE)
| (b1 << 1*PACKED_BYTE_SIZE)
| (b2 << 2*PACKED_BYTE_SIZE)
| (b3 << 3*PACKED_BYTE_SIZE));
}
private static boolean inRange(int bitset) {
assert((bitset & 0xFF) == bitset); // incoming values must fit in *unsigned* byte
return ((bitset & ~PACKED_BYTE_MASK) == 0);
}
private static byte[] fullBytes(int... byteValues) {
byte[] bytes = new byte[byteValues.length];
int i = 0;
for (int bv : byteValues) {
bytes[i++] = bval(bv);
}
assert(packedBytes(bytes) == 0);
return bytes;
}
private byte byteAt(int i) {
long pb = packedBytes;
if (pb == 0) {
if (i >= fullBytes.length) return 0;
return fullBytes[i];
}
assert(fullBytes == null);
if (i > PACKED_BYTE_MAX_LENGTH) return 0;
int pos = (i * PACKED_BYTE_SIZE);
return (byte)((pb >>> pos) & PACKED_BYTE_MASK);
}
Kind kind() { return Kind.values()[byteAt(0)]; }
private Transform(long packedBytes, byte[] fullBytes, LambdaForm result) {
super(result);
this.packedBytes = packedBytes;
this.fullBytes = fullBytes;
}
private Transform(long packedBytes) {
this(packedBytes, null, null);
assert(packedBytes != 0);
}
private Transform(byte[] fullBytes) {
this(0, fullBytes, null);
}
private static byte bval(int b) {
assert((b & 0xFF) == b); // incoming value must fit in *unsigned* byte
return (byte)b;
}
private static byte bval(Kind k) {
return bval(k.ordinal());
}
static Transform of(Kind k, int b1) {
byte b0 = bval(k);
if (inRange(b0 | b1))
return new Transform(packedBytes(b0, b1));
else
return new Transform(fullBytes(b0, b1));
}
static Transform of(Kind k, int b1, int b2) {
byte b0 = (byte) k.ordinal();
if (inRange(b0 | b1 | b2))
return new Transform(packedBytes(b0, b1, b2));
else
return new Transform(fullBytes(b0, b1, b2));
}
static Transform of(Kind k, int b1, int b2, int b3) {
byte b0 = (byte) k.ordinal();
if (inRange(b0 | b1 | b2 | b3))
return new Transform(packedBytes(b0, b1, b2, b3));
else
return new Transform(fullBytes(b0, b1, b2, b3));
}
private static final byte[] NO_BYTES = {};
static Transform of(Kind k, int... b123) {
return ofBothArrays(k, b123, NO_BYTES);
}
static Transform of(Kind k, int b1, byte[] b234) {
return ofBothArrays(k, new int[]{ b1 }, b234);
}
static Transform of(Kind k, int b1, int b2, byte[] b345) {
return ofBothArrays(k, new int[]{ b1, b2 }, b345);
}
private static Transform ofBothArrays(Kind k, int[] b123, byte[] b456) {
byte[] fullBytes = new byte[1 + b123.length + b456.length];
int i = 0;
fullBytes[i++] = bval(k);
for (int bv : b123) {
fullBytes[i++] = bval(bv);
}
for (byte bv : b456) {
fullBytes[i++] = bv;
}
long packedBytes = packedBytes(fullBytes);
if (packedBytes != 0)
return new Transform(packedBytes);
else
return new Transform(fullBytes);
}
Transform withResult(LambdaForm result) {
return new Transform(this.packedBytes, this.fullBytes, result);
}
@Override
public boolean equals(Object obj) {
return obj instanceof Transform && equals((Transform)obj);
}
public boolean equals(Transform that) {
return this.packedBytes == that.packedBytes && Arrays.equals(this.fullBytes, that.fullBytes);
}
@Override
public int hashCode() {
if (packedBytes != 0) {
assert(fullBytes == null);
return Long.hashCode(packedBytes);
}
return Arrays.hashCode(fullBytes);
}
@Override
public String toString() {
StringBuilder buf = new StringBuilder();
long bits = packedBytes;
if (bits != 0) {
buf.append("(");
while (bits != 0) {
buf.append(bits & PACKED_BYTE_MASK);
bits >>>= PACKED_BYTE_SIZE;
if (bits != 0) buf.append(",");
}
buf.append(")");
}
if (fullBytes != null) {
buf.append("unpacked");
buf.append(Arrays.toString(fullBytes));
}
LambdaForm result = get();
if (result != null) {
buf.append(" result=");
buf.append(result);
}
return buf.toString();
}
}
/** Find a previously cached transform equivalent to the given one, and return its result. */
private LambdaForm getInCache(Transform key) {
assert(key.get() == null);
// The transformCache is one of null, Transform, Transform[], or ConcurrentHashMap.
Object c = lambdaForm.transformCache;
Transform k = null;
if (c instanceof ConcurrentHashMap) {
@SuppressWarnings("unchecked")
ConcurrentHashMap<Transform,Transform> m = (ConcurrentHashMap<Transform,Transform>) c;
k = m.get(key);
} else if (c == null) {
return null;
} else if (c instanceof Transform) {
// one-element cache avoids overhead of an array
Transform t = (Transform)c;
if (t.equals(key)) k = t;
} else {
Transform[] ta = (Transform[])c;
for (int i = 0; i < ta.length; i++) {
Transform t = ta[i];
if (t == null) break;
if (t.equals(key)) { k = t; break; }
}
}
assert(k == null || key.equals(k));
return (k != null) ? k.get() : null;
}
/** Arbitrary but reasonable limits on Transform[] size for cache. */
private static final int MIN_CACHE_ARRAY_SIZE = 4, MAX_CACHE_ARRAY_SIZE = 16;
/** Cache a transform with its result, and return that result.
* But if an equivalent transform has already been cached, return its result instead.
*/
private LambdaForm putInCache(Transform key, LambdaForm form) {
key = key.withResult(form);
for (int pass = 0; ; pass++) {
Object c = lambdaForm.transformCache;
if (c instanceof ConcurrentHashMap) {
@SuppressWarnings("unchecked")
ConcurrentHashMap<Transform,Transform> m = (ConcurrentHashMap<Transform,Transform>) c;
Transform k = m.putIfAbsent(key, key);
if (k == null) return form;
LambdaForm result = k.get();
if (result != null) {
return result;
} else {
if (m.replace(key, k, key)) {
return form;
} else {
continue;
}
}
}
assert(pass == 0);
synchronized (lambdaForm) {
c = lambdaForm.transformCache;
if (c instanceof ConcurrentHashMap)
continue;
if (c == null) {
lambdaForm.transformCache = key;
return form;
}
Transform[] ta;
if (c instanceof Transform) {
Transform k = (Transform)c;
if (k.equals(key)) {
LambdaForm result = k.get();
if (result == null) {
lambdaForm.transformCache = key;
return form;
} else {
return result;
}
} else if (k.get() == null) { // overwrite stale entry
lambdaForm.transformCache = key;
return form;
}
// expand one-element cache to small array
ta = new Transform[MIN_CACHE_ARRAY_SIZE];
ta[0] = k;
lambdaForm.transformCache = ta;
} else {
// it is already expanded
ta = (Transform[])c;
}
int len = ta.length;
int stale = -1;
int i;
for (i = 0; i < len; i++) {
Transform k = ta[i];
if (k == null) {
break;
}
if (k.equals(key)) {
LambdaForm result = k.get();
if (result == null) {
ta[i] = key;
return form;
} else {
return result;
}
} else if (stale < 0 && k.get() == null) {
stale = i; // remember 1st stale entry index
}
}
if (i < len || stale >= 0) {
// just fall through to cache update
} else if (len < MAX_CACHE_ARRAY_SIZE) {
len = Math.min(len * 2, MAX_CACHE_ARRAY_SIZE);
ta = Arrays.copyOf(ta, len);
lambdaForm.transformCache = ta;
} else {
ConcurrentHashMap<Transform, Transform> m = new ConcurrentHashMap<>(MAX_CACHE_ARRAY_SIZE * 2);
for (Transform k : ta) {
m.put(k, k);
}
lambdaForm.transformCache = m;
// The second iteration will update for this query, concurrently.
continue;
}
int idx = (stale >= 0) ? stale : i;
ta[idx] = key;
return form;
}
}
}
private LambdaFormBuffer buffer() {
return new LambdaFormBuffer(lambdaForm);
}
/// Editing methods for method handles. These need to have fast paths.
private BoundMethodHandle.SpeciesData oldSpeciesData() {
return BoundMethodHandle.speciesData(lambdaForm);
}
private BoundMethodHandle.SpeciesData newSpeciesData(BasicType type) {
return oldSpeciesData().extendWith(type);
}
BoundMethodHandle bindArgumentL(BoundMethodHandle mh, int pos, Object value) {
assert(mh.speciesData() == oldSpeciesData());
BasicType bt = L_TYPE;
MethodType type2 = bindArgumentType(mh, pos, bt);
LambdaForm form2 = bindArgumentForm(1+pos);
return mh.copyWithExtendL(type2, form2, value);
}
BoundMethodHandle bindArgumentI(BoundMethodHandle mh, int pos, int value) {
assert(mh.speciesData() == oldSpeciesData());
BasicType bt = I_TYPE;
MethodType type2 = bindArgumentType(mh, pos, bt);
LambdaForm form2 = bindArgumentForm(1+pos);
return mh.copyWithExtendI(type2, form2, value);
}
BoundMethodHandle bindArgumentJ(BoundMethodHandle mh, int pos, long value) {
assert(mh.speciesData() == oldSpeciesData());
BasicType bt = J_TYPE;
MethodType type2 = bindArgumentType(mh, pos, bt);
LambdaForm form2 = bindArgumentForm(1+pos);
return mh.copyWithExtendJ(type2, form2, value);
}
BoundMethodHandle bindArgumentF(BoundMethodHandle mh, int pos, float value) {
assert(mh.speciesData() == oldSpeciesData());
BasicType bt = F_TYPE;
MethodType type2 = bindArgumentType(mh, pos, bt);
LambdaForm form2 = bindArgumentForm(1+pos);
return mh.copyWithExtendF(type2, form2, value);
}
BoundMethodHandle bindArgumentD(BoundMethodHandle mh, int pos, double value) {
assert(mh.speciesData() == oldSpeciesData());
BasicType bt = D_TYPE;
MethodType type2 = bindArgumentType(mh, pos, bt);
LambdaForm form2 = bindArgumentForm(1+pos);
return mh.copyWithExtendD(type2, form2, value);
}
private MethodType bindArgumentType(BoundMethodHandle mh, int pos, BasicType bt) {
assert(mh.form == lambdaForm);
assert(mh.form.names[1+pos].type == bt);
assert(BasicType.basicType(mh.type().parameterType(pos)) == bt);
return mh.type().dropParameterTypes(pos, pos+1);
}
/// Editing methods for lambda forms.
// Each editing method can (potentially) cache the edited LF so that it can be reused later.
LambdaForm bindArgumentForm(int pos) {
Transform key = Transform.of(Transform.Kind.BIND_ARG, pos);
LambdaForm form = getInCache(key);
if (form != null) {
assert(form.parameterConstraint(0) == newSpeciesData(lambdaForm.parameterType(pos)));
return form;
}
LambdaFormBuffer buf = buffer();
buf.startEdit();
BoundMethodHandle.SpeciesData oldData = oldSpeciesData();
BoundMethodHandle.SpeciesData newData = newSpeciesData(lambdaForm.parameterType(pos));
Name oldBaseAddress = lambdaForm.parameter(0); // BMH holding the values
Name newBaseAddress;
NamedFunction getter = newData.getterFunction(oldData.fieldCount());
if (pos != 0) {
// The newly created LF will run with a different BMH.
// Switch over any pre-existing BMH field references to the new BMH class.
buf.replaceFunctions(oldData.getterFunctions(), newData.getterFunctions(), oldBaseAddress);
newBaseAddress = oldBaseAddress.withConstraint(newData);
buf.renameParameter(0, newBaseAddress);
buf.replaceParameterByNewExpression(pos, new Name(getter, newBaseAddress));
} else {
// cannot bind the MH arg itself, unless oldData is empty
assert(oldData == BoundMethodHandle.SpeciesData.EMPTY);
newBaseAddress = new Name(L_TYPE).withConstraint(newData);
buf.replaceParameterByNewExpression(0, new Name(getter, newBaseAddress));
buf.insertParameter(0, newBaseAddress);
}
form = buf.endEdit();
return putInCache(key, form);
}
LambdaForm addArgumentForm(int pos, BasicType type) {
Transform key = Transform.of(Transform.Kind.ADD_ARG, pos, type.ordinal());
LambdaForm form = getInCache(key);
if (form != null) {
assert(form.arity == lambdaForm.arity+1);
assert(form.parameterType(pos) == type);
return form;
}
LambdaFormBuffer buf = buffer();
buf.startEdit();
buf.insertParameter(pos, new Name(type));
form = buf.endEdit();
return putInCache(key, form);
}
LambdaForm dupArgumentForm(int srcPos, int dstPos) {
Transform key = Transform.of(Transform.Kind.DUP_ARG, srcPos, dstPos);
LambdaForm form = getInCache(key);
if (form != null) {
assert(form.arity == lambdaForm.arity-1);
return form;
}
LambdaFormBuffer buf = buffer();
buf.startEdit();
assert(lambdaForm.parameter(srcPos).constraint == null);
assert(lambdaForm.parameter(dstPos).constraint == null);
buf.replaceParameterByCopy(dstPos, srcPos);
form = buf.endEdit();
return putInCache(key, form);
}
LambdaForm spreadArgumentsForm(int pos, Class<?> arrayType, int arrayLength) {
Class<?> elementType = arrayType.getComponentType();
Class<?> erasedArrayType = arrayType;
if (!elementType.isPrimitive())
erasedArrayType = Object[].class;
BasicType bt = basicType(elementType);
int elementTypeKey = bt.ordinal();
if (bt.basicTypeClass() != elementType) {
if (elementType.isPrimitive()) {
elementTypeKey = TYPE_LIMIT + Wrapper.forPrimitiveType(elementType).ordinal();
}
}
Transform key = Transform.of(Transform.Kind.SPREAD_ARGS, pos, elementTypeKey, arrayLength);
LambdaForm form = getInCache(key);
if (form != null) {
assert(form.arity == lambdaForm.arity - arrayLength + 1);
return form;
}
LambdaFormBuffer buf = buffer();
buf.startEdit();
assert(pos <= MethodType.MAX_JVM_ARITY);
assert(pos + arrayLength <= lambdaForm.arity);
assert(pos > 0); // cannot spread the MH arg itself
Name spreadParam = new Name(L_TYPE);
Name checkSpread = new Name(MethodHandleImpl.Lazy.NF_checkSpreadArgument, spreadParam, arrayLength);
// insert the new expressions
int exprPos = lambdaForm.arity();
buf.insertExpression(exprPos++, checkSpread);
// adjust the arguments
MethodHandle aload = MethodHandles.arrayElementGetter(erasedArrayType);
for (int i = 0; i < arrayLength; i++) {
Name loadArgument = new Name(aload, spreadParam, i);
buf.insertExpression(exprPos + i, loadArgument);
buf.replaceParameterByCopy(pos + i, exprPos + i);
}
buf.insertParameter(pos, spreadParam);
form = buf.endEdit();
return putInCache(key, form);
}
LambdaForm collectArgumentsForm(int pos, MethodType collectorType) {
int collectorArity = collectorType.parameterCount();
boolean dropResult = (collectorType.returnType() == void.class);
if (collectorArity == 1 && !dropResult) {
return filterArgumentForm(pos, basicType(collectorType.parameterType(0)));
}
BasicType[] newTypes = BasicType.basicTypes(collectorType.parameterList());
Transform.Kind kind = (dropResult
? Transform.Kind.COLLECT_ARGS_TO_VOID
: Transform.Kind.COLLECT_ARGS);
if (dropResult && collectorArity == 0) pos = 1; // pure side effect
Transform key = Transform.of(kind, pos, collectorArity, BasicType.basicTypesOrd(newTypes));
LambdaForm form = getInCache(key);
if (form != null) {
assert(form.arity == lambdaForm.arity - (dropResult ? 0 : 1) + collectorArity);
return form;
}
form = makeArgumentCombinationForm(pos, collectorType, false, dropResult);
return putInCache(key, form);
}
LambdaForm collectArgumentArrayForm(int pos, MethodHandle arrayCollector) {
MethodType collectorType = arrayCollector.type();
int collectorArity = collectorType.parameterCount();
assert(arrayCollector.intrinsicName() == Intrinsic.NEW_ARRAY);
Class<?> arrayType = collectorType.returnType();
Class<?> elementType = arrayType.getComponentType();
BasicType argType = basicType(elementType);
int argTypeKey = argType.ordinal();
if (argType.basicTypeClass() != elementType) {
// return null if it requires more metadata (like String[].class)
if (!elementType.isPrimitive())
return null;
argTypeKey = TYPE_LIMIT + Wrapper.forPrimitiveType(elementType).ordinal();
}
assert(collectorType.parameterList().equals(Collections.nCopies(collectorArity, elementType)));
Transform.Kind kind = Transform.Kind.COLLECT_ARGS_TO_ARRAY;
Transform key = Transform.of(kind, pos, collectorArity, argTypeKey);
LambdaForm form = getInCache(key);
if (form != null) {
assert(form.arity == lambdaForm.arity - 1 + collectorArity);
return form;
}
LambdaFormBuffer buf = buffer();
buf.startEdit();
assert(pos + 1 <= lambdaForm.arity);
assert(pos > 0); // cannot filter the MH arg itself
Name[] newParams = new Name[collectorArity];
for (int i = 0; i < collectorArity; i++) {
newParams[i] = new Name(pos + i, argType);
}
Name callCombiner = new Name(arrayCollector, (Object[]) /*...*/ newParams);
// insert the new expression
int exprPos = lambdaForm.arity();
buf.insertExpression(exprPos, callCombiner);
// insert new arguments
int argPos = pos + 1; // skip result parameter
for (Name newParam : newParams) {
buf.insertParameter(argPos++, newParam);
}
assert(buf.lastIndexOf(callCombiner) == exprPos+newParams.length);
buf.replaceParameterByCopy(pos, exprPos+newParams.length);
form = buf.endEdit();
return putInCache(key, form);
}
LambdaForm filterArgumentForm(int pos, BasicType newType) {
Transform key = Transform.of(Transform.Kind.FILTER_ARG, pos, newType.ordinal());
LambdaForm form = getInCache(key);
if (form != null) {
assert(form.arity == lambdaForm.arity);
assert(form.parameterType(pos) == newType);
return form;
}
BasicType oldType = lambdaForm.parameterType(pos);
MethodType filterType = MethodType.methodType(oldType.basicTypeClass(),
newType.basicTypeClass());
form = makeArgumentCombinationForm(pos, filterType, false, false);
return putInCache(key, form);
}
private LambdaForm makeArgumentCombinationForm(int pos,
MethodType combinerType,
boolean keepArguments, boolean dropResult) {
LambdaFormBuffer buf = buffer();
buf.startEdit();
int combinerArity = combinerType.parameterCount();
int resultArity = (dropResult ? 0 : 1);
assert(pos <= MethodType.MAX_JVM_ARITY);
assert(pos + resultArity + (keepArguments ? combinerArity : 0) <= lambdaForm.arity);
assert(pos > 0); // cannot filter the MH arg itself
assert(combinerType == combinerType.basicType());
assert(combinerType.returnType() != void.class || dropResult);
BoundMethodHandle.SpeciesData oldData = oldSpeciesData();
BoundMethodHandle.SpeciesData newData = newSpeciesData(L_TYPE);
// The newly created LF will run with a different BMH.
// Switch over any pre-existing BMH field references to the new BMH class.
Name oldBaseAddress = lambdaForm.parameter(0); // BMH holding the values
buf.replaceFunctions(oldData.getterFunctions(), newData.getterFunctions(), oldBaseAddress);
Name newBaseAddress = oldBaseAddress.withConstraint(newData);
buf.renameParameter(0, newBaseAddress);
Name getCombiner = new Name(newData.getterFunction(oldData.fieldCount()), newBaseAddress);
Object[] combinerArgs = new Object[1 + combinerArity];
combinerArgs[0] = getCombiner;
Name[] newParams;
if (keepArguments) {
newParams = new Name[0];
System.arraycopy(lambdaForm.names, pos + resultArity,
combinerArgs, 1, combinerArity);
} else {
newParams = new Name[combinerArity];
BasicType[] newTypes = basicTypes(combinerType.parameterList());
for (int i = 0; i < newTypes.length; i++) {
newParams[i] = new Name(pos + i, newTypes[i]);
}
System.arraycopy(newParams, 0,
combinerArgs, 1, combinerArity);
}
Name callCombiner = new Name(combinerType, combinerArgs);
// insert the two new expressions
int exprPos = lambdaForm.arity();
buf.insertExpression(exprPos+0, getCombiner);
buf.insertExpression(exprPos+1, callCombiner);
// insert new arguments, if needed
int argPos = pos + resultArity; // skip result parameter
for (Name newParam : newParams) {
buf.insertParameter(argPos++, newParam);
}
assert(buf.lastIndexOf(callCombiner) == exprPos+1+newParams.length);
if (!dropResult) {
buf.replaceParameterByCopy(pos, exprPos+1+newParams.length);
}
return buf.endEdit();
}
LambdaForm filterReturnForm(BasicType newType, boolean constantZero) {
Transform.Kind kind = (constantZero ? Transform.Kind.FILTER_RETURN_TO_ZERO : Transform.Kind.FILTER_RETURN);
Transform key = Transform.of(kind, newType.ordinal());
LambdaForm form = getInCache(key);
if (form != null) {
assert(form.arity == lambdaForm.arity);
assert(form.returnType() == newType);
return form;
}
LambdaFormBuffer buf = buffer();
buf.startEdit();
int insPos = lambdaForm.names.length;
Name callFilter;
if (constantZero) {
// Synthesize a constant zero value for the given type.
if (newType == V_TYPE)
callFilter = null;
else
callFilter = new Name(constantZero(newType));
} else {
BoundMethodHandle.SpeciesData oldData = oldSpeciesData();
BoundMethodHandle.SpeciesData newData = newSpeciesData(L_TYPE);
// The newly created LF will run with a different BMH.
// Switch over any pre-existing BMH field references to the new BMH class.
Name oldBaseAddress = lambdaForm.parameter(0); // BMH holding the values
buf.replaceFunctions(oldData.getterFunctions(), newData.getterFunctions(), oldBaseAddress);
Name newBaseAddress = oldBaseAddress.withConstraint(newData);
buf.renameParameter(0, newBaseAddress);
Name getFilter = new Name(newData.getterFunction(oldData.fieldCount()), newBaseAddress);
buf.insertExpression(insPos++, getFilter);
BasicType oldType = lambdaForm.returnType();
if (oldType == V_TYPE) {
MethodType filterType = MethodType.methodType(newType.basicTypeClass());
callFilter = new Name(filterType, getFilter);
} else {
MethodType filterType = MethodType.methodType(newType.basicTypeClass(), oldType.basicTypeClass());
callFilter = new Name(filterType, getFilter, lambdaForm.names[lambdaForm.result]);
}
}
if (callFilter != null)
buf.insertExpression(insPos++, callFilter);
buf.setResult(callFilter);
form = buf.endEdit();
return putInCache(key, form);
}
LambdaForm foldArgumentsForm(int foldPos, boolean dropResult, MethodType combinerType) {
int combinerArity = combinerType.parameterCount();
Transform.Kind kind = (dropResult ? Transform.Kind.FOLD_ARGS_TO_VOID : Transform.Kind.FOLD_ARGS);
Transform key = Transform.of(kind, foldPos, combinerArity);
LambdaForm form = getInCache(key);
if (form != null) {
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