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third-party-mirror/openjdk/jdk25u/HEAD/./src/java.base/share/classes/java/lang/invoke/MethodHandleImpl.java
blob: a759ec6162e1e56508b566880f23af8de7683914 [file]
/*
* Copyright (c) 2008, 2025, 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 jdk.internal.access.JavaLangInvokeAccess;
import jdk.internal.access.SharedSecrets;
import jdk.internal.constant.ClassOrInterfaceDescImpl;
import jdk.internal.constant.ConstantUtils;
import jdk.internal.constant.MethodTypeDescImpl;
import jdk.internal.foreign.abi.NativeEntryPoint;
import jdk.internal.reflect.CallerSensitive;
import jdk.internal.reflect.Reflection;
import jdk.internal.vm.annotation.ForceInline;
import jdk.internal.vm.annotation.Hidden;
import jdk.internal.vm.annotation.Stable;
import sun.invoke.empty.Empty;
import sun.invoke.util.ValueConversions;
import sun.invoke.util.VerifyType;
import sun.invoke.util.Wrapper;
import java.lang.classfile.ClassFile;
import java.lang.constant.ClassDesc;
import java.lang.foreign.MemoryLayout;
import java.lang.invoke.MethodHandles.Lookup;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.nio.ByteOrder;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Function;
import java.util.stream.Stream;
import static java.lang.classfile.ClassFile.*;
import static java.lang.constant.ConstantDescs.*;
import static java.lang.invoke.LambdaForm.*;
import static java.lang.invoke.MethodHandleNatives.Constants.MN_CALLER_SENSITIVE;
import static java.lang.invoke.MethodHandleNatives.Constants.MN_HIDDEN_MEMBER;
import static java.lang.invoke.MethodHandleNatives.Constants.NESTMATE_CLASS;
import static java.lang.invoke.MethodHandleStatics.*;
import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
/**
* Trusted implementation code for MethodHandle.
* @author jrose
*/
/*non-public*/
abstract class MethodHandleImpl {
/// Factory methods to create method handles:
static MethodHandle makeArrayElementAccessor(Class<?> arrayClass, ArrayAccess access) {
if (arrayClass == Object[].class) {
return ArrayAccess.objectAccessor(access);
}
if (!arrayClass.isArray())
throw newIllegalArgumentException("not an array: "+arrayClass);
MethodHandle[] cache = ArrayAccessor.TYPED_ACCESSORS.get(arrayClass);
int cacheIndex = ArrayAccess.cacheIndex(access);
MethodHandle mh = cache[cacheIndex];
if (mh != null) return mh;
mh = ArrayAccessor.getAccessor(arrayClass, access);
MethodType correctType = ArrayAccessor.correctType(arrayClass, access);
if (mh.type() != correctType) {
assert(mh.type().parameterType(0) == Object[].class);
/* if access == SET */ assert(access != ArrayAccess.SET || mh.type().parameterType(2) == Object.class);
/* if access == GET */ assert(access != ArrayAccess.GET ||
(mh.type().returnType() == Object.class &&
correctType.parameterType(0).getComponentType() == correctType.returnType()));
// safe to view non-strictly, because element type follows from array type
mh = mh.viewAsType(correctType, false);
}
mh = makeIntrinsic(mh, ArrayAccess.intrinsic(access));
// Atomically update accessor cache.
synchronized(cache) {
if (cache[cacheIndex] == null) {
cache[cacheIndex] = mh;
} else {
// Throw away newly constructed accessor and use cached version.
mh = cache[cacheIndex];
}
}
return mh;
}
enum ArrayAccess {
GET, SET, LENGTH;
// As ArrayAccess and ArrayAccessor have a circular dependency, the ArrayAccess properties cannot be stored in
// final fields.
static String opName(ArrayAccess a) {
return switch (a) {
case GET -> "getElement";
case SET -> "setElement";
case LENGTH -> "length";
default -> throw unmatchedArrayAccess(a);
};
}
static MethodHandle objectAccessor(ArrayAccess a) {
return switch (a) {
case GET -> ArrayAccessor.OBJECT_ARRAY_GETTER;
case SET -> ArrayAccessor.OBJECT_ARRAY_SETTER;
case LENGTH -> ArrayAccessor.OBJECT_ARRAY_LENGTH;
default -> throw unmatchedArrayAccess(a);
};
}
static int cacheIndex(ArrayAccess a) {
return switch (a) {
case GET -> ArrayAccessor.GETTER_INDEX;
case SET -> ArrayAccessor.SETTER_INDEX;
case LENGTH -> ArrayAccessor.LENGTH_INDEX;
default -> throw unmatchedArrayAccess(a);
};
}
static Intrinsic intrinsic(ArrayAccess a) {
return switch (a) {
case GET -> Intrinsic.ARRAY_LOAD;
case SET -> Intrinsic.ARRAY_STORE;
case LENGTH -> Intrinsic.ARRAY_LENGTH;
default -> throw unmatchedArrayAccess(a);
};
}
}
static InternalError unmatchedArrayAccess(ArrayAccess a) {
return newInternalError("should not reach here (unmatched ArrayAccess: " + a + ")");
}
static final class ArrayAccessor {
/// Support for array element and length access
static final int GETTER_INDEX = 0, SETTER_INDEX = 1, LENGTH_INDEX = 2, INDEX_LIMIT = 3;
static final ClassValue<MethodHandle[]> TYPED_ACCESSORS
= new ClassValue<MethodHandle[]>() {
@Override
protected MethodHandle[] computeValue(Class<?> type) {
return new MethodHandle[INDEX_LIMIT];
}
};
static final MethodHandle OBJECT_ARRAY_GETTER, OBJECT_ARRAY_SETTER, OBJECT_ARRAY_LENGTH;
static {
MethodHandle[] cache = TYPED_ACCESSORS.get(Object[].class);
cache[GETTER_INDEX] = OBJECT_ARRAY_GETTER = makeIntrinsic(getAccessor(Object[].class, ArrayAccess.GET), Intrinsic.ARRAY_LOAD);
cache[SETTER_INDEX] = OBJECT_ARRAY_SETTER = makeIntrinsic(getAccessor(Object[].class, ArrayAccess.SET), Intrinsic.ARRAY_STORE);
cache[LENGTH_INDEX] = OBJECT_ARRAY_LENGTH = makeIntrinsic(getAccessor(Object[].class, ArrayAccess.LENGTH), Intrinsic.ARRAY_LENGTH);
assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_GETTER.internalMemberName()));
assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_SETTER.internalMemberName()));
assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_LENGTH.internalMemberName()));
}
static int getElementI(int[] a, int i) { return a[i]; }
static long getElementJ(long[] a, int i) { return a[i]; }
static float getElementF(float[] a, int i) { return a[i]; }
static double getElementD(double[] a, int i) { return a[i]; }
static boolean getElementZ(boolean[] a, int i) { return a[i]; }
static byte getElementB(byte[] a, int i) { return a[i]; }
static short getElementS(short[] a, int i) { return a[i]; }
static char getElementC(char[] a, int i) { return a[i]; }
static Object getElementL(Object[] a, int i) { return a[i]; }
static void setElementI(int[] a, int i, int x) { a[i] = x; }
static void setElementJ(long[] a, int i, long x) { a[i] = x; }
static void setElementF(float[] a, int i, float x) { a[i] = x; }
static void setElementD(double[] a, int i, double x) { a[i] = x; }
static void setElementZ(boolean[] a, int i, boolean x) { a[i] = x; }
static void setElementB(byte[] a, int i, byte x) { a[i] = x; }
static void setElementS(short[] a, int i, short x) { a[i] = x; }
static void setElementC(char[] a, int i, char x) { a[i] = x; }
static void setElementL(Object[] a, int i, Object x) { a[i] = x; }
static int lengthI(int[] a) { return a.length; }
static int lengthJ(long[] a) { return a.length; }
static int lengthF(float[] a) { return a.length; }
static int lengthD(double[] a) { return a.length; }
static int lengthZ(boolean[] a) { return a.length; }
static int lengthB(byte[] a) { return a.length; }
static int lengthS(short[] a) { return a.length; }
static int lengthC(char[] a) { return a.length; }
static int lengthL(Object[] a) { return a.length; }
static String name(Class<?> arrayClass, ArrayAccess access) {
Class<?> elemClass = arrayClass.getComponentType();
if (elemClass == null) throw newIllegalArgumentException("not an array", arrayClass);
return ArrayAccess.opName(access) + Wrapper.basicTypeChar(elemClass);
}
static MethodType type(Class<?> arrayClass, ArrayAccess access) {
Class<?> elemClass = arrayClass.getComponentType();
Class<?> arrayArgClass = arrayClass;
if (!elemClass.isPrimitive()) {
arrayArgClass = Object[].class;
elemClass = Object.class;
}
return switch (access) {
case GET -> MethodType.methodType(elemClass, arrayArgClass, int.class);
case SET -> MethodType.methodType(void.class, arrayArgClass, int.class, elemClass);
case LENGTH -> MethodType.methodType(int.class, arrayArgClass);
default -> throw unmatchedArrayAccess(access);
};
}
static MethodType correctType(Class<?> arrayClass, ArrayAccess access) {
Class<?> elemClass = arrayClass.getComponentType();
return switch (access) {
case GET -> MethodType.methodType(elemClass, arrayClass, int.class);
case SET -> MethodType.methodType(void.class, arrayClass, int.class, elemClass);
case LENGTH -> MethodType.methodType(int.class, arrayClass);
default -> throw unmatchedArrayAccess(access);
};
}
static MethodHandle getAccessor(Class<?> arrayClass, ArrayAccess access) {
String name = name(arrayClass, access);
MethodType type = type(arrayClass, access);
try {
return IMPL_LOOKUP.findStatic(ArrayAccessor.class, name, type);
} catch (ReflectiveOperationException ex) {
throw uncaughtException(ex);
}
}
}
/**
* 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.
* The argument conversions allowed are casting, boxing and unboxing,
* integral widening or narrowing, and floating point widening or narrowing.
* @param srcType required call type
* @param target original method handle
* @param strict if true, only asType conversions are allowed; if false, explicitCastArguments conversions allowed
* @param monobox if true, unboxing conversions are assumed to be exactly typed (Integer to int only, not long or double)
* @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(MethodHandle target, MethodType srcType,
boolean strict, boolean monobox) {
MethodType dstType = target.type();
if (srcType == dstType)
return target;
return makePairwiseConvertByEditor(target, srcType, strict, monobox);
}
private static int countNonNull(Object[] array) {
int count = 0;
if (array != null) {
for (Object x : array) {
if (x != null) ++count;
}
}
return count;
}
static MethodHandle makePairwiseConvertByEditor(MethodHandle target, MethodType srcType,
boolean strict, boolean monobox) {
// In method types arguments start at index 0, while the LF
// editor have the MH receiver at position 0 - adjust appropriately.
final int MH_RECEIVER_OFFSET = 1;
Object[] convSpecs = computeValueConversions(srcType, target.type(), strict, monobox);
int convCount = countNonNull(convSpecs);
if (convCount == 0)
return target.viewAsType(srcType, strict);
MethodType basicSrcType = srcType.basicType();
MethodType midType = target.type().basicType();
BoundMethodHandle mh = target.rebind();
// Match each unique conversion to the positions at which it is to be applied
HashMap<Object, int[]> convSpecMap = HashMap.newHashMap(convCount);
for (int i = 0; i < convSpecs.length - MH_RECEIVER_OFFSET; i++) {
Object convSpec = convSpecs[i];
if (convSpec == null) continue;
int[] positions = convSpecMap.get(convSpec);
if (positions == null) {
positions = new int[] { i + MH_RECEIVER_OFFSET };
} else {
positions = Arrays.copyOf(positions, positions.length + 1);
positions[positions.length - 1] = i + MH_RECEIVER_OFFSET;
}
convSpecMap.put(convSpec, positions);
}
for (var entry : convSpecMap.entrySet()) {
Object convSpec = entry.getKey();
MethodHandle fn;
if (convSpec instanceof Class) {
fn = getConstantHandle(MH_cast).bindTo(convSpec);
} else {
fn = (MethodHandle) convSpec;
}
int[] positions = entry.getValue();
Class<?> newType = basicSrcType.parameterType(positions[0] - MH_RECEIVER_OFFSET);
BasicType newBasicType = BasicType.basicType(newType);
convCount -= positions.length;
if (convCount == 0) {
midType = srcType;
} else {
Class<?>[] ptypes = midType.ptypes().clone();
for (int pos : positions) {
ptypes[pos - 1] = newType;
}
midType = MethodType.methodType(midType.rtype(), ptypes, true);
}
LambdaForm form2;
if (positions.length > 1) {
form2 = mh.editor().filterRepeatedArgumentForm(newBasicType, positions);
} else {
form2 = mh.editor().filterArgumentForm(positions[0], newBasicType);
}
mh = mh.copyWithExtendL(midType, form2, fn);
}
Object convSpec = convSpecs[convSpecs.length - 1];
if (convSpec != null) {
MethodHandle fn;
if (convSpec instanceof Class) {
if (convSpec == void.class)
fn = null;
else
fn = getConstantHandle(MH_cast).bindTo(convSpec);
} else {
fn = (MethodHandle) convSpec;
}
Class<?> newType = basicSrcType.returnType();
assert(--convCount == 0);
midType = srcType;
if (fn != null) {
mh = mh.rebind(); // rebind if too complex
LambdaForm form2 = mh.editor().filterReturnForm(BasicType.basicType(newType), false);
mh = mh.copyWithExtendL(midType, form2, fn);
} else {
LambdaForm form2 = mh.editor().filterReturnForm(BasicType.basicType(newType), true);
mh = mh.copyWith(midType, form2);
}
}
assert(convCount == 0);
assert(mh.type().equals(srcType));
return mh;
}
static Object[] computeValueConversions(MethodType srcType, MethodType dstType,
boolean strict, boolean monobox) {
final int INARG_COUNT = srcType.parameterCount();
Object[] convSpecs = null;
for (int i = 0; i <= INARG_COUNT; i++) {
boolean isRet = (i == INARG_COUNT);
Class<?> src = isRet ? dstType.returnType() : srcType.parameterType(i);
Class<?> dst = isRet ? srcType.returnType() : dstType.parameterType(i);
if (!VerifyType.isNullConversion(src, dst, /*keepInterfaces=*/ strict)) {
if (convSpecs == null) {
convSpecs = new Object[INARG_COUNT + 1];
}
convSpecs[i] = valueConversion(src, dst, strict, monobox);
}
}
return convSpecs;
}
static MethodHandle makePairwiseConvert(MethodHandle target, MethodType srcType,
boolean strict) {
return makePairwiseConvert(target, srcType, strict, /*monobox=*/ false);
}
/**
* Find a conversion function from the given source to the given destination.
* This conversion function will be used as a LF NamedFunction.
* Return a Class object if a simple cast is needed.
* Return void.class if void is involved.
*/
static Object valueConversion(Class<?> src, Class<?> dst, boolean strict, boolean monobox) {
assert(!VerifyType.isNullConversion(src, dst, /*keepInterfaces=*/ strict)); // caller responsibility
if (dst == void.class)
return dst;
MethodHandle fn;
if (src.isPrimitive()) {
if (src == void.class) {
return void.class; // caller must recognize this specially
} else if (dst.isPrimitive()) {
// Examples: int->byte, byte->int, boolean->int (!strict)
fn = ValueConversions.convertPrimitive(src, dst);
} else {
// Examples: int->Integer, boolean->Object, float->Number
Wrapper wsrc = Wrapper.forPrimitiveType(src);
fn = ValueConversions.boxExact(wsrc);
assert(fn.type().parameterType(0) == wsrc.primitiveType());
assert(fn.type().returnType() == wsrc.wrapperType());
if (!VerifyType.isNullConversion(wsrc.wrapperType(), dst, strict)) {
// Corner case, such as int->Long, which will probably fail.
MethodType mt = MethodType.methodType(dst, src);
if (strict)
fn = fn.asType(mt);
else
fn = MethodHandleImpl.makePairwiseConvert(fn, mt, /*strict=*/ false);
}
}
} else if (dst.isPrimitive()) {
Wrapper wdst = Wrapper.forPrimitiveType(dst);
if (monobox || src == wdst.wrapperType()) {
// Use a strongly-typed unboxer, if possible.
fn = ValueConversions.unboxExact(wdst, strict);
} else {
// Examples: Object->int, Number->int, Comparable->int, Byte->int
// must include additional conversions
// src must be examined at runtime, to detect Byte, Character, etc.
fn = (strict
? ValueConversions.unboxWiden(wdst)
: ValueConversions.unboxCast(wdst));
}
} 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.
return dst;
}
assert(fn.type().parameterCount() <= 1) : "pc"+Arrays.asList(src.getSimpleName(), dst.getSimpleName(), fn);
return fn;
}
static MethodHandle makeVarargsCollector(MethodHandle target, Class<?> arrayType) {
MethodType type = target.type();
int last = type.parameterCount() - 1;
if (type.parameterType(last) != arrayType)
target = target.asType(type.changeParameterType(last, arrayType));
target = target.asFixedArity(); // make sure this attribute is turned off
return new AsVarargsCollector(target, arrayType);
}
static final class AsVarargsCollector extends DelegatingMethodHandle {
private final MethodHandle target;
private final Class<?> arrayType;
private MethodHandle asCollectorCache;
AsVarargsCollector(MethodHandle target, Class<?> arrayType) {
this(target.type(), target, arrayType);
}
AsVarargsCollector(MethodType type, MethodHandle target, Class<?> arrayType) {
super(type, target);
this.target = target;
this.arrayType = arrayType;
}
@Override
public boolean isVarargsCollector() {
return true;
}
@Override
protected MethodHandle getTarget() {
return target;
}
@Override
public MethodHandle asFixedArity() {
return target;
}
@Override
MethodHandle setVarargs(MemberName member) {
if (member.isVarargs()) return this;
return asFixedArity();
}
@Override
public MethodHandle withVarargs(boolean makeVarargs) {
if (makeVarargs) return this;
return asFixedArity();
}
@Override
public MethodHandle asTypeUncached(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 asFixedArity().asType(newType);
}
// check cache
MethodHandle acc = asCollectorCache;
if (acc != null && acc.type().parameterCount() == newArity)
return acc.asType(newType);
// build and cache a collector
int arrayLength = newArity - collectArg;
MethodHandle collector;
try {
collector = asFixedArity().asCollector(arrayType, arrayLength);
assert(collector.type().parameterCount() == newArity) : "newArity="+newArity+" but collector="+collector;
} catch (IllegalArgumentException ex) {
throw new WrongMethodTypeException("cannot build collector", ex);
}
asCollectorCache = collector;
return collector.asType(newType);
}
@Override
boolean viewAsTypeChecks(MethodType newType, boolean strict) {
super.viewAsTypeChecks(newType, true);
if (strict) return true;
// extra assertion for non-strict checks:
assert (type().lastParameterType().getComponentType()
.isAssignableFrom(
newType.lastParameterType().getComponentType()))
: Arrays.asList(this, newType);
return true;
}
@Override
public Object invokeWithArguments(Object... arguments) throws Throwable {
MethodType type = this.type();
int argc;
final int MAX_SAFE = 127; // 127 longs require 254 slots, which is safe to spread
if (arguments == null
|| (argc = arguments.length) <= MAX_SAFE
|| argc < type.parameterCount()) {
return super.invokeWithArguments(arguments);
}
// a jumbo invocation requires more explicit reboxing of the trailing arguments
int uncollected = type.parameterCount() - 1;
Class<?> elemType = arrayType.getComponentType();
int collected = argc - uncollected;
Object collArgs = (elemType == Object.class)
? new Object[collected] : Array.newInstance(elemType, collected);
if (!elemType.isPrimitive()) {
// simple cast: just do some casting
try {
System.arraycopy(arguments, uncollected, collArgs, 0, collected);
} catch (ArrayStoreException ex) {
return super.invokeWithArguments(arguments);
}
} else {
// corner case of flat array requires reflection (or specialized copy loop)
MethodHandle arraySetter = MethodHandles.arrayElementSetter(arrayType);
try {
for (int i = 0; i < collected; i++) {
arraySetter.invoke(collArgs, i, arguments[uncollected + i]);
}
} catch (WrongMethodTypeException|ClassCastException ex) {
return super.invokeWithArguments(arguments);
}
}
// chop the jumbo list down to size and call in non-varargs mode
Object[] newArgs = new Object[uncollected + 1];
System.arraycopy(arguments, 0, newArgs, 0, uncollected);
newArgs[uncollected] = collArgs;
return asFixedArity().invokeWithArguments(newArgs);
}
}
static void checkSpreadArgument(Object av, int n) {
if (av == null && n == 0) {
return;
} else if (av == null) {
throw new NullPointerException("null array reference");
} else if (av instanceof Object[] array) {
int len = array.length;
if (len == n) return;
} else {
int len = java.lang.reflect.Array.getLength(av);
if (len == n) return;
}
// fall through to error:
throw newIllegalArgumentException("array is not of length "+n);
}
@Hidden
static MethodHandle selectAlternative(boolean testResult, MethodHandle target, MethodHandle fallback) {
if (testResult) {
return target;
} else {
return fallback;
}
}
// Intrinsified by C2. Counters are used during parsing to calculate branch frequencies.
@Hidden
@jdk.internal.vm.annotation.IntrinsicCandidate
static boolean profileBoolean(boolean result, int[] counters) {
// Profile is int[2] where [0] and [1] correspond to false and true occurrences respectively.
int idx = result ? 1 : 0;
try {
counters[idx] = Math.addExact(counters[idx], 1);
} catch (ArithmeticException e) {
// Avoid continuous overflow by halving the problematic count.
counters[idx] = counters[idx] / 2;
}
return result;
}
// Intrinsified by C2. Returns true if obj is a compile-time constant.
@Hidden
@jdk.internal.vm.annotation.IntrinsicCandidate
static boolean isCompileConstant(Object obj) {
return false;
}
static MethodHandle makeGuardWithTest(MethodHandle test,
MethodHandle target,
MethodHandle fallback) {
MethodType type = target.type();
assert(test.type().equals(type.changeReturnType(boolean.class)) && fallback.type().equals(type));
MethodType basicType = type.basicType();
LambdaForm form = makeGuardWithTestForm(basicType);
BoundMethodHandle mh;
try {
if (PROFILE_GWT) {
int[] counts = new int[2];
mh = (BoundMethodHandle)
BoundMethodHandle.speciesData_LLLL().factory().invokeBasic(type, form,
(Object) test, (Object) profile(target), (Object) profile(fallback), counts);
} else {
mh = (BoundMethodHandle)
BoundMethodHandle.speciesData_LLL().factory().invokeBasic(type, form,
(Object) test, (Object) profile(target), (Object) profile(fallback));
}
} catch (Throwable ex) {
throw uncaughtException(ex);
}
assert(mh.type() == type);
return mh;
}
static MethodHandle profile(MethodHandle target) {
if (DONT_INLINE_THRESHOLD >= 0) {
return makeBlockInliningWrapper(target);
} else {
return target;
}
}
/**
* Block inlining during JIT-compilation of a target method handle if it hasn't been invoked enough times.
* Corresponding LambdaForm has @DontInline when compiled into bytecode.
*/
static MethodHandle makeBlockInliningWrapper(MethodHandle target) {
LambdaForm lform;
if (DONT_INLINE_THRESHOLD > 0) {
lform = Makers.PRODUCE_BLOCK_INLINING_FORM.apply(target);
} else {
lform = Makers.PRODUCE_REINVOKER_FORM.apply(target);
}
return new CountingWrapper(target, lform,
Makers.PRODUCE_BLOCK_INLINING_FORM, Makers.PRODUCE_REINVOKER_FORM,
DONT_INLINE_THRESHOLD);
}
private static final class Makers {
/** Constructs reinvoker lambda form which block inlining during JIT-compilation for a particular method handle */
static final Function<MethodHandle, LambdaForm> PRODUCE_BLOCK_INLINING_FORM = new Function<MethodHandle, LambdaForm>() {
@Override
public LambdaForm apply(MethodHandle target) {
return DelegatingMethodHandle.makeReinvokerForm(target,
MethodTypeForm.LF_DELEGATE_BLOCK_INLINING, CountingWrapper.class, false,
DelegatingMethodHandle.NF_getTarget, CountingWrapper.NF_maybeStopCounting);
}
};
/** Constructs simple reinvoker lambda form for a particular method handle */
static final Function<MethodHandle, LambdaForm> PRODUCE_REINVOKER_FORM = new Function<MethodHandle, LambdaForm>() {
@Override
public LambdaForm apply(MethodHandle target) {
return DelegatingMethodHandle.makeReinvokerForm(target,
MethodTypeForm.LF_DELEGATE, DelegatingMethodHandle.class, DelegatingMethodHandle.NF_getTarget);
}
};
/** Maker of type-polymorphic varargs */
static final ClassValue<MethodHandle[]> TYPED_COLLECTORS = new ClassValue<MethodHandle[]>() {
@Override
protected MethodHandle[] computeValue(Class<?> type) {
return new MethodHandle[MAX_JVM_ARITY + 1];
}
};
}
/**
* Counting method handle. It has 2 states: counting and non-counting.
* It is in counting state for the first n invocations and then transitions to non-counting state.
* Behavior in counting and non-counting states is determined by lambda forms produced by
* countingFormProducer & nonCountingFormProducer respectively.
*/
static final class CountingWrapper extends DelegatingMethodHandle {
private final MethodHandle target;
private int count;
private Function<MethodHandle, LambdaForm> countingFormProducer;
private Function<MethodHandle, LambdaForm> nonCountingFormProducer;
private volatile boolean isCounting;
private CountingWrapper(MethodHandle target, LambdaForm lform,
Function<MethodHandle, LambdaForm> countingFromProducer,
Function<MethodHandle, LambdaForm> nonCountingFormProducer,
int count) {
super(target.type(), lform);
this.target = target;
this.count = count;
this.countingFormProducer = countingFromProducer;
this.nonCountingFormProducer = nonCountingFormProducer;
this.isCounting = (count > 0);
}
@Hidden
@Override
protected MethodHandle getTarget() {
return target;
}
@Override
public MethodHandle asTypeUncached(MethodType newType) {
MethodHandle newTarget = target.asType(newType);
MethodHandle wrapper;
if (isCounting) {
LambdaForm lform;
lform = countingFormProducer.apply(newTarget);
wrapper = new CountingWrapper(newTarget, lform, countingFormProducer, nonCountingFormProducer, DONT_INLINE_THRESHOLD);
} else {
wrapper = newTarget; // no need for a counting wrapper anymore
}
return wrapper;
}
boolean countDown() {
int c = count;
target.maybeCustomize(); // customize if counting happens for too long
if (c <= 1) {
// Try to limit number of updates. MethodHandle.updateForm() doesn't guarantee LF update visibility.
if (isCounting) {
isCounting = false;
return true;
} else {
return false;
}
} else {
count = c - 1;
return false;
}
}
@Hidden
static void maybeStopCounting(Object o1) {
final CountingWrapper wrapper = (CountingWrapper) o1;
if (wrapper.countDown()) {
// Reached invocation threshold. Replace counting behavior with a non-counting one.
wrapper.updateForm(new Function<>() {
public LambdaForm apply(LambdaForm oldForm) {
LambdaForm lform = wrapper.nonCountingFormProducer.apply(wrapper.target);
lform.compileToBytecode(); // speed up warmup by avoiding LF interpretation again after transition
return lform;
}});
}
}
static final NamedFunction NF_maybeStopCounting;
static {
Class<?> THIS_CLASS = CountingWrapper.class;
try {
NF_maybeStopCounting = new NamedFunction(THIS_CLASS.getDeclaredMethod("maybeStopCounting", Object.class));
} catch (ReflectiveOperationException ex) {
throw newInternalError(ex);
}
}
}
static LambdaForm makeGuardWithTestForm(MethodType basicType) {
LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWT);
if (lform != null) return lform;
final int THIS_MH = 0; // the BMH_LLL
final int ARG_BASE = 1; // start of incoming arguments
final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
int nameCursor = ARG_LIMIT;
final int GET_TEST = nameCursor++;
final int GET_TARGET = nameCursor++;
final int GET_FALLBACK = nameCursor++;
final int GET_COUNTERS = PROFILE_GWT ? nameCursor++ : -1;
final int CALL_TEST = nameCursor++;
final int PROFILE = (GET_COUNTERS != -1) ? nameCursor++ : -1;
final int TEST = nameCursor-1; // previous statement: either PROFILE or CALL_TEST
final int SELECT_ALT = nameCursor++;
final int CALL_TARGET = nameCursor++;
assert(CALL_TARGET == SELECT_ALT+1); // must be true to trigger IBG.emitSelectAlternative
Name[] names = invokeArguments(nameCursor - ARG_LIMIT, basicType);
BoundMethodHandle.SpeciesData data =
(GET_COUNTERS != -1) ? BoundMethodHandle.speciesData_LLLL()
: BoundMethodHandle.speciesData_LLL();
names[THIS_MH] = names[THIS_MH].withConstraint(data);
names[GET_TEST] = new Name(data.getterFunction(0), names[THIS_MH]);
names[GET_TARGET] = new Name(data.getterFunction(1), names[THIS_MH]);
names[GET_FALLBACK] = new Name(data.getterFunction(2), names[THIS_MH]);
if (GET_COUNTERS != -1) {
names[GET_COUNTERS] = new Name(data.getterFunction(3), names[THIS_MH]);
}
Object[] invokeArgs = Arrays.copyOfRange(names, 0, ARG_LIMIT, Object[].class);
// call test
MethodType testType = basicType.changeReturnType(boolean.class).basicType();
invokeArgs[0] = names[GET_TEST];
names[CALL_TEST] = new Name(testType, invokeArgs);
// profile branch
if (PROFILE != -1) {
names[PROFILE] = new Name(getFunction(NF_profileBoolean), names[CALL_TEST], names[GET_COUNTERS]);
}
// call selectAlternative
names[SELECT_ALT] = new Name(new NamedFunction(
makeIntrinsic(getConstantHandle(MH_selectAlternative), Intrinsic.SELECT_ALTERNATIVE)),
names[TEST], names[GET_TARGET], names[GET_FALLBACK]);
// call target or fallback
invokeArgs[0] = names[SELECT_ALT];
names[CALL_TARGET] = new Name(basicType, invokeArgs);
lform = LambdaForm.create(basicType.parameterCount() + 1, names, /*forceInline=*/true, Kind.GUARD);
return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWT, lform);
}
/**
* The LambdaForm shape for catchException combinator is the following:
* <blockquote><pre>{@code
* guardWithCatch=Lambda(a0:L,a1:L,a2:L)=>{
* t3:L=BoundMethodHandle$Species_LLLLL.argL0(a0:L);
* t4:L=BoundMethodHandle$Species_LLLLL.argL1(a0:L);
* t5:L=BoundMethodHandle$Species_LLLLL.argL2(a0:L);
* t6:L=BoundMethodHandle$Species_LLLLL.argL3(a0:L);
* t7:L=BoundMethodHandle$Species_LLLLL.argL4(a0:L);
* t8:L=MethodHandle.invokeBasic(t6:L,a1:L,a2:L);
* t9:L=MethodHandleImpl.guardWithCatch(t3:L,t4:L,t5:L,t8:L);
* t10:I=MethodHandle.invokeBasic(t7:L,t9:L);t10:I}
* }</pre></blockquote>
*
* argL0 and argL2 are target and catcher method handles. argL1 is exception class.
* argL3 and argL4 are auxiliary method handles: argL3 boxes arguments and wraps them into Object[]
* (ValueConversions.array()) and argL4 unboxes result if necessary (ValueConversions.unbox()).
*
* Having t8 and t10 passed outside and not hardcoded into a lambda form allows to share lambda forms
* among catchException combinators with the same basic type.
*/
private static LambdaForm makeGuardWithCatchForm(MethodType basicType) {
LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWC);
if (lform != null) {
return lform;
}
final int THIS_MH = 0; // the BMH_LLLLL
final int ARG_BASE = 1; // start of incoming arguments
final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
int nameCursor = ARG_LIMIT;
final int GET_TARGET = nameCursor++;
final int GET_CLASS = nameCursor++;
final int GET_CATCHER = nameCursor++;
final int GET_COLLECT_ARGS = nameCursor++;
final int GET_UNBOX_RESULT = nameCursor++;
final int BOXED_ARGS = nameCursor++;
final int TRY_CATCH = nameCursor++;
final int UNBOX_RESULT = nameCursor++;
Name[] names = invokeArguments(nameCursor - ARG_LIMIT, basicType);
BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
names[THIS_MH] = names[THIS_MH].withConstraint(data);
names[GET_TARGET] = new Name(data.getterFunction(0), names[THIS_MH]);
names[GET_CLASS] = new Name(data.getterFunction(1), names[THIS_MH]);
names[GET_CATCHER] = new Name(data.getterFunction(2), names[THIS_MH]);
names[GET_COLLECT_ARGS] = new Name(data.getterFunction(3), names[THIS_MH]);
names[GET_UNBOX_RESULT] = new Name(data.getterFunction(4), names[THIS_MH]);
// FIXME: rework argument boxing/result unboxing logic for LF interpretation
// t_{i}:L=MethodHandle.invokeBasic(collectArgs:L,a1:L,...);
MethodType collectArgsType = basicType.changeReturnType(Object.class);
MethodHandle invokeBasic = MethodHandles.basicInvoker(collectArgsType);
Object[] args = new Object[invokeBasic.type().parameterCount()];
args[0] = names[GET_COLLECT_ARGS];
System.arraycopy(names, ARG_BASE, args, 1, ARG_LIMIT-ARG_BASE);
names[BOXED_ARGS] = new Name(new NamedFunction(makeIntrinsic(invokeBasic, Intrinsic.GUARD_WITH_CATCH)), args);
// t_{i+1}:L=MethodHandleImpl.guardWithCatch(target:L,exType:L,catcher:L,t_{i}:L);
Object[] gwcArgs = new Object[] {names[GET_TARGET], names[GET_CLASS], names[GET_CATCHER], names[BOXED_ARGS]};
names[TRY_CATCH] = new Name(getFunction(NF_guardWithCatch), gwcArgs);
// t_{i+2}:I=MethodHandle.invokeBasic(unbox:L,t_{i+1}:L);
MethodHandle invokeBasicUnbox = MethodHandles.basicInvoker(MethodType.methodType(basicType.rtype(), Object.class));
Object[] unboxArgs = new Object[] {names[GET_UNBOX_RESULT], names[TRY_CATCH]};
names[UNBOX_RESULT] = new Name(invokeBasicUnbox, unboxArgs);
lform = LambdaForm.create(basicType.parameterCount() + 1, names, Kind.GUARD_WITH_CATCH);
return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWC, lform);
}
static MethodHandle makeGuardWithCatch(MethodHandle target,
Class<? extends Throwable> exType,
MethodHandle catcher) {
MethodType type = target.type();
LambdaForm form = makeGuardWithCatchForm(type.basicType());
// Prepare auxiliary method handles used during LambdaForm interpretation.
// Box arguments and wrap them into Object[]: ValueConversions.array().
MethodType varargsType = type.changeReturnType(Object[].class);
MethodHandle collectArgs = varargsArray(type.parameterCount()).asType(varargsType);
MethodHandle unboxResult = unboxResultHandle(type.returnType());
BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
BoundMethodHandle mh;
try {
mh = (BoundMethodHandle) data.factory().invokeBasic(type, form, (Object) target, (Object) exType,
(Object) catcher, (Object) collectArgs, (Object) unboxResult);
} catch (Throwable ex) {
throw uncaughtException(ex);
}
assert(mh.type() == type);
return mh;
}
/**
* Intrinsified during LambdaForm compilation
* (see {@link InvokerBytecodeGenerator#emitGuardWithCatch emitGuardWithCatch}).
*/
@Hidden
static Object guardWithCatch(MethodHandle target, Class<? extends Throwable> exType, MethodHandle catcher,
Object... av) throws Throwable {
// Use asFixedArity() to avoid unnecessary boxing of last argument for VarargsCollector case.
try {
return target.asFixedArity().invokeWithArguments(av);
} catch (Throwable t) {
if (!exType.isInstance(t)) throw t;
return catcher.asFixedArity().invokeWithArguments(prepend(av, t));
}
}
/** Prepend elements to an array. */
@Hidden
private static Object[] prepend(Object[] array, Object... elems) {
int nArray = array.length;
int nElems = elems.length;
Object[] newArray = new Object[nArray + nElems];
System.arraycopy(elems, 0, newArray, 0, nElems);
System.arraycopy(array, 0, newArray, nElems, nArray);
return newArray;
}
static MethodHandle throwException(MethodType type) {
assert(Throwable.class.isAssignableFrom(type.parameterType(0)));
int arity = type.parameterCount();
if (arity > 1) {
MethodHandle mh = throwException(type.dropParameterTypes(1, arity));
mh = MethodHandles.dropArgumentsTrusted(mh, 1, Arrays.copyOfRange(type.ptypes(), 1, arity));
return mh;
}
return makePairwiseConvert(getFunction(NF_throwException).resolvedHandle(), type, false, true);
}
static <T extends Throwable> Empty throwException(T t) throws T { throw t; }
static MethodHandle[] FAKE_METHOD_HANDLE_INVOKE = new MethodHandle[2];
static MethodHandle fakeMethodHandleInvoke(MemberName method) {
assert(method.isMethodHandleInvoke());
int idx = switch (method.getName()) {
case "invoke" -> 0;
case "invokeExact" -> 1;
default -> throw new InternalError(method.getName());
};
MethodHandle mh = FAKE_METHOD_HANDLE_INVOKE[idx];
if (mh != null) return mh;
MethodType type = MethodType.methodType(Object.class, UnsupportedOperationException.class,
MethodHandle.class, Object[].class);
mh = throwException(type);
mh = mh.bindTo(new UnsupportedOperationException("cannot reflectively invoke MethodHandle"));
if (!method.getInvocationType().equals(mh.type()))
throw new InternalError(method.toString());
mh = mh.withInternalMemberName(method, false);
mh = mh.withVarargs(true);
assert(method.isVarargs());
FAKE_METHOD_HANDLE_INVOKE[idx] = mh;
return mh;
}
static MethodHandle fakeVarHandleInvoke(MemberName method) {
// TODO caching, is it necessary?
MethodType type = MethodType.methodType(method.getMethodType().returnType(),
UnsupportedOperationException.class,
VarHandle.class, Object[].class);
MethodHandle mh = throwException(type);
mh = mh.bindTo(new UnsupportedOperationException("cannot reflectively invoke VarHandle"));
if (!method.getInvocationType().equals(mh.type()))
throw new InternalError(method.toString());
mh = mh.withInternalMemberName(method, false);
mh = mh.asVarargsCollector(Object[].class);
assert(method.isVarargs());
return mh;
}
/**
* Create an alias for the method handle which, when called,
* appears to be called from the same class loader and protection domain
* as hostClass.
* This is an expensive no-op unless the method which is called
* is sensitive to its caller. A small number of system methods
* are in this category, including Class.forName and Method.invoke.
*/
static MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
return BindCaller.bindCaller(mh, hostClass);
}
// Put the whole mess into its own nested class.
// That way we can lazily load the code and set up the constants.
private static class BindCaller {
private static final ClassDesc CD_Object_array = ConstantUtils.CD_Object_array;
private static final MethodType INVOKER_MT = MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
private static final MethodType REFLECT_INVOKER_MT = MethodType.methodType(Object.class, MethodHandle.class, Object.class, Object[].class);
static MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
// Code in the boot layer should now be careful while creating method handles or
// functional interface instances created from method references to @CallerSensitive methods,
// it needs to be ensured the handles or interface instances are kept safe and are not passed
// from the boot layer to untrusted code.
if (hostClass == null
|| (hostClass.isArray() ||
hostClass.isPrimitive() ||
hostClass.getName().startsWith("java.lang.invoke."))) {
throw new InternalError(); // does not happen, and should not anyway
}
MemberName member = mh.internalMemberName();
if (member != null) {
// Look up the CSM adapter method with the same method name
// but with an additional caller class parameter. If present,
// bind the adapter's method handle with the lookup class as
// the caller class argument
MemberName csmAdapter = IMPL_LOOKUP.resolveOrNull(member.getReferenceKind(),
new MemberName(member.getDeclaringClass(),
member.getName(),
member.getMethodType().appendParameterTypes(Class.class),
member.getReferenceKind()));
if (csmAdapter != null) {
assert !csmAdapter.isCallerSensitive();
MethodHandle dmh = DirectMethodHandle.make(csmAdapter);
dmh = MethodHandles.insertArguments(dmh, dmh.type().parameterCount() - 1, hostClass);
dmh = new WrappedMember(dmh, mh.type(), member, mh.isInvokeSpecial(), hostClass);
return dmh;
}
}
// If no adapter method for CSM with an additional Class parameter
// is present, then inject an invoker class that is the caller
// invoking the method handle of the CSM
try {
return bindCallerWithInjectedInvoker(mh, hostClass);
} catch (ReflectiveOperationException ex) {
throw uncaughtException(ex);
}
}
private static MethodHandle bindCallerWithInjectedInvoker(MethodHandle mh, Class<?> hostClass)
throws ReflectiveOperationException
{
// For simplicity, convert mh to a varargs-like method.
MethodHandle vamh = prepareForInvoker(mh);
// Cache the result of makeInjectedInvoker once per argument class.
MethodHandle bccInvoker = CV_makeInjectedInvoker.get(hostClass).invoker();
return restoreToType(bccInvoker.bindTo(vamh), mh, hostClass);
}
private static Class<?> makeInjectedInvoker(Class<?> targetClass) {
/*
* The invoker class defined to the same class loader as the lookup class
* but in an unnamed package so that the class bytes can be cached and
* reused for any @CSM.
*
* @CSM must be public and exported if called by any module.
*/
String name = targetClass.getName() + "$$InjectedInvoker";
if (targetClass.isHidden()) {
// use the original class name
name = name.replace('/', '_');
}
name = name.replace('.', '/');
Class<?> invokerClass = new Lookup(targetClass)
.makeHiddenClassDefiner(name, INJECTED_INVOKER_TEMPLATE, dumper(), NESTMATE_CLASS)
.defineClass(true, targetClass);
assert checkInjectedInvoker(targetClass, invokerClass);
return invokerClass;
}
private static ClassValue<InjectedInvokerHolder> CV_makeInjectedInvoker = new ClassValue<>() {
@Override
protected InjectedInvokerHolder computeValue(Class<?> hostClass) {
return new InjectedInvokerHolder(makeInjectedInvoker(hostClass));
}
};
/*
* Returns a method handle of an invoker class injected for reflection
* implementation use with the following signature:
* reflect_invoke_V(MethodHandle mh, Object target, Object[] args)
*
* Method::invoke on a caller-sensitive method will call
* MethodAccessorImpl::invoke(Object, Object[]) through reflect_invoke_V
* target.csm(args)
* NativeMethodAccessorImpl::invoke(target, args)
* MethodAccessImpl::invoke(target, args)
* InjectedInvoker::reflect_invoke_V(vamh, target, args);
* method::invoke(target, args)
* p.Foo::m
*
* An injected invoker class is a hidden class which has the same
* defining class loader, runtime package, and protection domain
* as the given caller class.
*/
static MethodHandle reflectiveInvoker(Class<?> caller) {
return BindCaller.CV_makeInjectedInvoker.get(caller).reflectInvoker();
}
private static final class InjectedInvokerHolder {
private final Class<?> invokerClass;
// lazily resolved and cached DMH(s) of invoke_V methods
private MethodHandle invoker;
private MethodHandle reflectInvoker;
private InjectedInvokerHolder(Class<?> invokerClass) {
this.invokerClass = invokerClass;
}
private MethodHandle invoker() {
var mh = invoker;
if (mh == null) {
try {
invoker = mh = IMPL_LOOKUP.findStatic(invokerClass, "invoke_V", INVOKER_MT);
} catch (Error | RuntimeException ex) {
throw ex;
} catch (Throwable ex) {
throw new InternalError(ex);
}
}
return mh;
}
private MethodHandle reflectInvoker() {
var mh = reflectInvoker;
if (mh == null) {
try {
reflectInvoker = mh = IMPL_LOOKUP.findStatic(invokerClass, "reflect_invoke_V", REFLECT_INVOKER_MT);
} catch (Error | RuntimeException ex) {
throw ex;
} catch (Throwable ex) {
throw new InternalError(ex);
}
}
return mh;
}
}
// Adapt mh so that it can be called directly from an injected invoker:
private static MethodHandle prepareForInvoker(MethodHandle mh) {
mh = mh.asFixedArity();
MethodType mt = mh.type();
int arity = mt.parameterCount();
MethodHandle vamh = mh.asType(mt.generic());
vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
vamh = vamh.asSpreader(Object[].class, arity);
vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
return vamh;
}
// Undo the adapter effect of prepareForInvoker:
private static MethodHandle restoreToType(MethodHandle vamh,
MethodHandle original,
Class<?> hostClass) {
MethodType type = original.type();
MethodHandle mh = vamh.asCollector(Object[].class, type.parameterCount());
MemberName member = original.internalMemberName();
mh = mh.asType(type);
mh = new WrappedMember(mh, type, member, original.isInvokeSpecial(), hostClass);
return mh;
}
private static boolean checkInjectedInvoker(Class<?> hostClass, Class<?> invokerClass) {
assert (hostClass.getClassLoader() == invokerClass.getClassLoader()) : hostClass.getName()+" (CL)";
assert (hostClass.getProtectionDomain() == invokerClass.getProtectionDomain()) : hostClass.getName()+" (PD)";
try {
// Test the invoker to ensure that it really injects into the right place.
MethodHandle invoker = IMPL_LOOKUP.findStatic(invokerClass, "invoke_V", INVOKER_MT);
MethodHandle vamh = prepareForInvoker(MH_checkCallerClass);
return (boolean)invoker.invoke(vamh, new Object[]{ invokerClass });
} catch (Error|RuntimeException ex) {
throw ex;
} catch (Throwable ex) {
throw new InternalError(ex);
}
}
private static final MethodHandle MH_checkCallerClass;
static {
final Class<?> THIS_CLASS = BindCaller.class;
assert(checkCallerClass(THIS_CLASS));
try {
MH_checkCallerClass = IMPL_LOOKUP
.findStatic(THIS_CLASS, "checkCallerClass",
MethodType.methodType(boolean.class, Class.class));
assert((boolean) MH_checkCallerClass.invokeExact(THIS_CLASS));
} catch (Throwable ex) {
throw new InternalError(ex);
}
}
@CallerSensitive
@ForceInline // to ensure Reflection.getCallerClass optimization
private static boolean checkCallerClass(Class<?> expected) {
// This method is called via MH_checkCallerClass and so it's correct to ask for the immediate caller here.
Class<?> actual = Reflection.getCallerClass();
if (actual != expected)
throw new InternalError("found " + actual.getName() + ", expected " + expected.getName());
return true;
}
private static final byte[] INJECTED_INVOKER_TEMPLATE = generateInvokerTemplate();
/** Produces byte code for a class that is used as an injected invoker. */
private static byte[] generateInvokerTemplate() {
// private static class InjectedInvoker {
// /* this is used to wrap DMH(s) of caller-sensitive methods */
// @Hidden
// static Object invoke_V(MethodHandle vamh, Object[] args) throws Throwable {
// return vamh.invokeExact(args);
// }
// /* this is used in caller-sensitive reflective method accessor */
// @Hidden
// static Object reflect_invoke_V(MethodHandle vamh, Object target, Object[] args) throws Throwable {
// return vamh.invokeExact(target, args);
// }
// }
// }
return ClassFile.of().build(ClassOrInterfaceDescImpl.ofValidated("LInjectedInvoker;"), clb -> clb
.withFlags(ACC_PRIVATE | ACC_SUPER)
.withMethodBody(
"invoke_V",
MethodTypeDescImpl.ofValidated(CD_Object, CD_MethodHandle, CD_Object_array),
ACC_STATIC,
cob -> cob.aload(0)
.aload(1)
.invokevirtual(CD_MethodHandle, "invokeExact", MethodTypeDescImpl.ofValidated(CD_Object, CD_Object_array))
.areturn())
.withMethodBody(
"reflect_invoke_V",
MethodTypeDescImpl.ofValidated(CD_Object, CD_MethodHandle, CD_Object, CD_Object_array),
ACC_STATIC,
cob -> cob.aload(0)
.aload(1)
.aload(2)
.invokevirtual(CD_MethodHandle, "invokeExact", MethodTypeDescImpl.ofValidated(CD_Object, CD_Object, CD_Object_array))
.areturn()));
}
}
/** This subclass allows a wrapped method handle to be re-associated with an arbitrary member name. */
static final class WrappedMember extends DelegatingMethodHandle {
private final MethodHandle target;
private final MemberName member;
private final Class<?> callerClass;
private final boolean isInvokeSpecial;
private WrappedMember(MethodHandle target, MethodType type,
MemberName member, boolean isInvokeSpecial,
Class<?> callerClass) {
super(type, target);
this.target = target;
this.member = member;
this.callerClass = callerClass;
this.isInvokeSpecial = isInvokeSpecial;
}
@Override
MemberName internalMemberName() {
return member;
}
@Override
Class<?> internalCallerClass() {
return callerClass;
}
@Override
boolean isInvokeSpecial() {
return isInvokeSpecial;
}
@Override
protected MethodHandle getTarget() {
return target;
}
@Override
public MethodHandle asTypeUncached(MethodType newType) {
// This MH is an alias for target, except for the MemberName
// Drop the MemberName if there is any conversion.
return target.asType(newType);
}
}
static MethodHandle makeWrappedMember(MethodHandle target, MemberName member, boolean isInvokeSpecial) {
if (member.equals(target.internalMemberName()) && isInvokeSpecial == target.isInvokeSpecial())
return target;
return new WrappedMember(target, target.type(), member, isInvokeSpecial, null);
}
/** Intrinsic IDs */
/*non-public*/
enum Intrinsic {
SELECT_ALTERNATIVE,
GUARD_WITH_CATCH,
TRY_FINALLY,
TABLE_SWITCH,
LOOP,
ARRAY_LOAD,
ARRAY_STORE,
ARRAY_LENGTH,
IDENTITY,
NONE // no intrinsic associated
}
/** Mark arbitrary method handle as intrinsic.
* InvokerBytecodeGenerator uses this info to produce more efficient bytecode shape. */
static final class IntrinsicMethodHandle extends DelegatingMethodHandle {
private final MethodHandle target;
private final Intrinsic intrinsicName;
private final Object intrinsicData;
IntrinsicMethodHandle(MethodHandle target, Intrinsic intrinsicName) {
this(target, intrinsicName, null);
}
IntrinsicMethodHandle(MethodHandle target, Intrinsic intrinsicName, Object intrinsicData) {
super(target.type(), target);
this.target = target;
this.intrinsicName = intrinsicName;
this.intrinsicData = intrinsicData;
}
@Override
protected MethodHandle getTarget() {
return target;
}
@Override
Intrinsic intrinsicName() {
return intrinsicName;
}
@Override
Object intrinsicData() {
return intrinsicData;
}
@Override
public MethodHandle asTypeUncached(MethodType newType) {
// This MH is an alias for target, except for the intrinsic name
// Drop the name if there is any conversion.
return target.asType(newType);
}
@Override
String internalProperties() {
return super.internalProperties() +
"\n& Intrinsic="+intrinsicName;
}
@Override
public MethodHandle asCollector(Class<?> arrayType, int arrayLength) {
if (intrinsicName == Intrinsic.IDENTITY) {
MethodType resultType = type().asCollectorType(arrayType, type().parameterCount() - 1, arrayLength);
MethodHandle newArray = MethodHandleImpl.varargsArray(arrayType, arrayLength);
return newArray.asType(resultType);
}
return super.asCollector(arrayType, arrayLength);
}
}
static MethodHandle makeIntrinsic(MethodHandle target, Intrinsic intrinsicName) {
return makeIntrinsic(target, intrinsicName, null);
}
static MethodHandle makeIntrinsic(MethodHandle target, Intrinsic intrinsicName, Object intrinsicData) {
if (intrinsicName == target.intrinsicName())
return target;
return new IntrinsicMethodHandle(target, intrinsicName, intrinsicData);
}
static MethodHandle makeIntrinsic(MethodType type, LambdaForm form, Intrinsic intrinsicName) {
return new IntrinsicMethodHandle(SimpleMethodHandle.make(type, form), intrinsicName);
}
private static final @Stable MethodHandle[] ARRAYS = new MethodHandle[MAX_ARITY + 1];
/** Return a method handle that takes the indicated number of Object
* arguments and returns an Object array of them, as if for varargs.
*/
static MethodHandle varargsArray(int nargs) {
MethodHandle mh = ARRAYS[nargs];
if (mh != null) {
return mh;
}
mh = makeCollector(Object[].class, nargs);
assert(assertCorrectArity(mh, nargs));
return ARRAYS[nargs] = mh;
}
/** Return a method handle that takes the indicated number of
* typed arguments and returns an array of them.
* The type argument is the array type.
*/
static MethodHandle varargsArray(Class<?> arrayType, int nargs) {
Class<?> elemType = arrayType.getComponentType();
if (elemType == null) throw new IllegalArgumentException("not an array: "+arrayType);
if (nargs >= MAX_JVM_ARITY/2 - 1) {
int slots = nargs;
final int MAX_ARRAY_SLOTS = MAX_JVM_ARITY - 1; // 1 for receiver MH
if (slots <= MAX_ARRAY_SLOTS && elemType.isPrimitive())
slots *= Wrapper.forPrimitiveType(elemType).stackSlots();
if (slots > MAX_ARRAY_SLOTS)
throw new IllegalArgumentException("too many arguments: "+arrayType.getSimpleName()+", length "+nargs);
}
if (elemType == Object.class)
return varargsArray(nargs);
// other cases: primitive arrays, subtypes of Object[]
MethodHandle cache[] = Makers.TYPED_COLLECTORS.get(elemType);
MethodHandle mh = nargs < cache.length ? cache[nargs] : null;
if (mh != null) return mh;
mh = makeCollector(arrayType, nargs);
assert(assertCorrectArity(mh, nargs));
if (nargs < cache.length)
cache[nargs] = mh;
return mh;
}
private static boolean assertCorrectArity(MethodHandle mh, int arity) {
assert(mh.type().parameterCount() == arity) : "arity != "+arity+": "+mh;
return true;
}
static final int MAX_JVM_ARITY = 255; // limit imposed by the JVM
/*non-public*/
static void assertSame(Object mh1, Object mh2) {
if (mh1 != mh2) {
String msg = String.format("mh1 != mh2: mh1 = %s (form: %s); mh2 = %s (form: %s)",
mh1, ((MethodHandle)mh1).form,
mh2, ((MethodHandle)mh2).form);
throw newInternalError(msg);
}
}
// Local constant functions:
/* non-public */
static final byte NF_checkSpreadArgument = 0,
NF_guardWithCatch = 1,
NF_throwException = 2,
NF_tryFinally = 3,
NF_loop = 4,
NF_profileBoolean = 5,
NF_tableSwitch = 6,
NF_LIMIT = 7;
private static final @Stable NamedFunction[] NFS = new NamedFunction[NF_LIMIT];
static NamedFunction getFunction(byte func) {
NamedFunction nf = NFS[func];
if (nf != null) {
return nf;
}
return NFS[func] = createFunction(func);
}
private static NamedFunction createFunction(byte func) {
try {
return switch (func) {
case NF_checkSpreadArgument -> new NamedFunction(MethodHandleImpl.class
.getDeclaredMethod("checkSpreadArgument", Object.class, int.class));
case NF_guardWithCatch -> new NamedFunction(MethodHandleImpl.class
.getDeclaredMethod("guardWithCatch", MethodHandle.class, Class.class,
MethodHandle.class, Object[].class));
case NF_tryFinally -> new NamedFunction(MethodHandleImpl.class
.getDeclaredMethod("tryFinally", MethodHandle.class, MethodHandle.class, Object[].class));
case NF_loop -> new NamedFunction(MethodHandleImpl.class
.getDeclaredMethod("loop", BasicType[].class, LoopClauses.class, Object[].class));
case NF_throwException -> new NamedFunction(MethodHandleImpl.class
.getDeclaredMethod("throwException", Throwable.class));
case NF_profileBoolean -> new NamedFunction(MethodHandleImpl.class
.getDeclaredMethod("profileBoolean", boolean.class, int[].class));
case NF_tableSwitch -> new NamedFunction(MethodHandleImpl.class
.getDeclaredMethod("tableSwitch", int.class, MethodHandle.class, CasesHolder.class, Object[].class));
default -> throw new InternalError("Undefined function: " + func);
};
} catch (ReflectiveOperationException ex) {
throw newInternalError(ex);
}
}
static {
runtimeSetup();
}
// Also called from JVM when loading an AOT cache
private static void runtimeSetup() {
SharedSecrets.setJavaLangInvokeAccess(new JavaLangInvokeAccess() {
@Override
public Class<?> getDeclaringClass(Object rmname) {
ResolvedMethodName method = (ResolvedMethodName)rmname;
return method.declaringClass();
}
@Override
public MethodType getMethodType(String descriptor, ClassLoader loader) {
return MethodType.fromDescriptor(descriptor, loader);
}
public boolean isCallerSensitive(int flags) {
return (flags & MN_CALLER_SENSITIVE) == MN_CALLER_SENSITIVE;
}
public boolean isHiddenMember(int flags) {
return (flags & MN_HIDDEN_MEMBER) == MN_HIDDEN_MEMBER;
}
@Override
public Map<String, byte[]> generateHolderClasses(Stream<String> traces) {
return GenerateJLIClassesHelper.generateHolderClasses(traces);
}
@Override
public VarHandle memorySegmentViewHandle(Class<?> carrier, MemoryLayout enclosing, long alignmentMask, ByteOrder order, boolean constantOffset, long offset) {
return VarHandles.memorySegmentViewHandle(carrier, enclosing, alignmentMask, constantOffset, offset, order);
}
@Override
public MethodHandle nativeMethodHandle(NativeEntryPoint nep) {
return NativeMethodHandle.make(nep);
}
@Override
public VarHandle filterValue(VarHandle target, MethodHandle filterToTarget, MethodHandle filterFromTarget) {
return VarHandles.filterValue(target, filterToTarget, filterFromTarget);
}
@Override
public VarHandle filterCoordinates(VarHandle target, int pos, MethodHandle... filters) {
return VarHandles.filterCoordinates(target, pos, filters);
}
@Override
public VarHandle dropCoordinates(VarHandle target, int pos, Class<?>... valueTypes) {
return VarHandles.dropCoordinates(target, pos, valueTypes);
}
@Override
public VarHandle permuteCoordinates(VarHandle target, List<Class<?>> newCoordinates, int... reorder) {
return VarHandles.permuteCoordinates(target, newCoordinates, reorder);
}
@Override
public VarHandle collectCoordinates(VarHandle target, int pos, MethodHandle filter) {
return VarHandles.collectCoordinates(target, pos, filter);
}
@Override
public VarHandle insertCoordinates(VarHandle target, int pos, Object... values) {
return VarHandles.insertCoordinates(target, pos, values);
}
@Override
public MethodHandle unreflectConstructor(Constructor<?> ctor) throws IllegalAccessException {
return IMPL_LOOKUP.unreflectConstructor(ctor);
}
@Override
public MethodHandle unreflectField(Field field, boolean isSetter) throws IllegalAccessException {
return isSetter ? IMPL_LOOKUP.unreflectSetter(field) : IMPL_LOOKUP.unreflectGetter(field);
}
@Override
public MethodHandle findVirtual(Class<?> defc, String name, MethodType type) throws IllegalAccessException {
try {
return IMPL_LOOKUP.findVirtual(defc, name, type);
} catch (NoSuchMethodException e) {
return null;
}
}
@Override
public MethodHandle findStatic(Class<?> defc, String name, MethodType type) throws IllegalAccessException {
try {
return IMPL_LOOKUP.findStatic(defc, name, type);
} catch (NoSuchMethodException e) {
return null;
}
}
@Override
public MethodHandle reflectiveInvoker(Class<?> caller) {
Objects.requireNonNull(caller);
return BindCaller.reflectiveInvoker(caller);
}
@Override
public Class<?>[] exceptionTypes(MethodHandle handle) {
return VarHandles.exceptionTypes(handle);
}
@Override
public MethodHandle serializableConstructor(Class<?> decl, Constructor<?> ctorToCall) throws IllegalAccessException {
return IMPL_LOOKUP.serializableConstructor(decl, ctorToCall);
}
});
}
/** Result unboxing: ValueConversions.unbox() OR ValueConversions.identity() OR ValueConversions.ignore(). */
private static MethodHandle unboxResultHandle(Class<?> returnType) {
if (returnType.isPrimitive()) {
if (returnType == void.class) {
return ValueConversions.ignore();
} else {
Wrapper w = Wrapper.forPrimitiveType(returnType);
return ValueConversions.unboxExact(w);
}
} else {
return MethodHandles.identity(Object.class);
}
}
/**
* Assembles a loop method handle from the given handles and type information.
*
* @param tloop the return type of the loop.
* @param targs types of the arguments to be passed to the loop.
* @param init sanitized array of initializers for loop-local variables.
* @param step sanitized array of loop bodies.
* @param pred sanitized array of predicates.
* @param fini sanitized array of loop finalizers.
*
* @return a handle that, when invoked, will execute the loop.
*/
static MethodHandle makeLoop(Class<?> tloop, List<Class<?>> targs, List<MethodHandle> init, List<MethodHandle> step,
List<MethodHandle> pred, List<MethodHandle> fini) {
MethodType type = MethodType.methodType(tloop, targs);
BasicType[] initClauseTypes =
init.stream().map(h -> h.type().returnType()).map(BasicType::basicType).toArray(BasicType[]::new);
LambdaForm form = makeLoopForm(type.basicType(), initClauseTypes);
// Prepare auxiliary method handles used during LambdaForm interpretation.
// Box arguments and wrap them into Object[]: ValueConversions.array().
MethodType varargsType = type.changeReturnType(Object[].class);
MethodHandle collectArgs = varargsArray(type.parameterCount()).asType(varargsType);
MethodHandle unboxResult = unboxResultHandle(tloop);
LoopClauses clauseData =
new LoopClauses(new MethodHandle[][]{toArray(init), toArray(step), toArray(pred), toArray(fini)});
BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLL();
BoundMethodHandle mh;
try {
mh = (BoundMethodHandle) data.factory().invokeBasic(type, form, (Object) clauseData,
(Object) collectArgs, (Object) unboxResult);
} catch (Throwable ex) {
throw uncaughtException(ex);
}
assert(mh.type() == type);
return mh;
}
private static MethodHandle[] toArray(List<MethodHandle> l) {
return l.toArray(new MethodHandle[0]);
}
/**
* Loops introduce some complexity as they can have additional local state. Hence, LambdaForms for loops are
* generated from a template. The LambdaForm template shape for the loop combinator is as follows (assuming one
* reference parameter passed in {@code a1}, and a reference return type, with the return value represented by
* {@code t12}):
* <blockquote><pre>{@code
* loop=Lambda(a0:L,a1:L)=>{
* t2:L=BoundMethodHandle$Species_L3.argL0(a0:L); // LoopClauses holding init, step, pred, fini handles
* t3:L=BoundMethodHandle$Species_L3.argL1(a0:L); // helper handle to box the arguments into an Object[]
* t4:L=BoundMethodHandle$Species_L3.argL2(a0:L); // helper handle to unbox the result
* t5:L=MethodHandle.invokeBasic(t3:L,a1:L); // box the arguments into an Object[]
* t6:L=MethodHandleImpl.loop(null,t2:L,t3:L); // call the loop executor
* t7:L=MethodHandle.invokeBasic(t4:L,t6:L);t7:L} // unbox the result; return the result
* }</pre></blockquote>
* <p>
* {@code argL0} is a LoopClauses instance holding, in a 2-dimensional array, the init, step, pred, and fini method
* handles. {@code argL1} and {@code argL2} are auxiliary method handles: {@code argL1} boxes arguments and wraps
* them into {@code Object[]} ({@code ValueConversions.array()}), and {@code argL2} unboxes the result if necessary
* ({@code ValueConversions.unbox()}).
* <p>
* Having {@code t3} and {@code t4} passed in via a BMH and not hardcoded in the lambda form allows to share lambda
* forms among loop combinators with the same basic type.
* <p>
* The above template is instantiated by using the {@link LambdaFormEditor} to replace the {@code null} argument to
* the {@code loop} invocation with the {@code BasicType} array describing the loop clause types. This argument is
* ignored in the loop invoker, but will be extracted and used in {@linkplain InvokerBytecodeGenerator#emitLoop(int)
* bytecode generation}.
*/
private static LambdaForm makeLoopForm(MethodType basicType, BasicType[] localVarTypes) {
final int THIS_MH = 0; // the BMH_LLL
final int ARG_BASE = 1; // start of incoming arguments
final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
int nameCursor = ARG_LIMIT;
final int GET_CLAUSE_DATA = nameCursor++;
final int GET_COLLECT_ARGS = nameCursor++;
final int GET_UNBOX_RESULT = nameCursor++;
final int BOXED_ARGS = nameCursor++;
final int LOOP = nameCursor++;
final int UNBOX_RESULT = nameCursor++;
LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_LOOP);
if (lform == null) {
Name[] names = invokeArguments(nameCursor - ARG_LIMIT, basicType);
BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLL();
names[THIS_MH] = names[THIS_MH].withConstraint(data);
names[GET_CLAUSE_DATA] = new Name(data.getterFunction(0), names[THIS_MH]);
names[GET_COLLECT_ARGS] = new Name(data.getterFunction(1), names[THIS_MH]);
names[GET_UNBOX_RESULT] = new Name(data.getterFunction(2), names[THIS_MH]);
// t_{i}:L=MethodHandle.invokeBasic(collectArgs:L,a1:L,...);
MethodType collectArgsType = basicType.changeReturnType(Object.class);
MethodHandle invokeBasic = MethodHandles.basicInvoker(collectArgsType);
Object[] args = new Object[invokeBasic.type().parameterCount()];
args[0] = names[GET_COLLECT_ARGS];
System.arraycopy(names, ARG_BASE, args, 1, ARG_LIMIT - ARG_BASE);
names[BOXED_ARGS] = new Name(new NamedFunction(makeIntrinsic(invokeBasic, Intrinsic.LOOP)), args);
// t_{i+1}:L=MethodHandleImpl.loop(localTypes:L,clauses:L,t_{i}:L);
Object[] lArgs =
new Object[]{null, // placeholder for BasicType[] localTypes - will be added by LambdaFormEditor
names[GET_CLAUSE_DATA], names[BOXED_ARGS]};
names[LOOP] = new Name(getFunction(NF_loop), lArgs);
// t_{i+2}:I=MethodHandle.invokeBasic(unbox:L,t_{i+1}:L);
MethodHandle invokeBasicUnbox = MethodHandles.basicInvoker(MethodType.methodType(basicType.rtype(), Object.class));
Object[] unboxArgs = new Object[]{names[GET_UNBOX_RESULT], names[LOOP]};
names[UNBOX_RESULT] = new Name(invokeBasicUnbox, unboxArgs);
lform = basicType.form().setCachedLambdaForm(MethodTypeForm.LF_LOOP,
LambdaForm.create(basicType.parameterCount() + 1, names, Kind.LOOP));
}
// BOXED_ARGS is the index into the names array where the loop idiom starts
return lform.editor().noteLoopLocalTypesForm(BOXED_ARGS, localVarTypes);
}
static class LoopClauses {
@Stable final MethodHandle[][] clauses;
LoopClauses(MethodHandle[][] clauses) {
assert clauses.length == 4;
this.clauses = clauses;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder("LoopClauses -- ");
for (int i = 0; i < 4; ++i) {
if (i > 0) {
sb.append(" ");
}
sb.append('<').append(i).append(">: ");
MethodHandle[] hs = clauses[i];
for (int j = 0; j < hs.length; ++j) {
if (j > 0) {
sb.append(" ");
}
sb.append('*').append(j).append(": ").append(hs[j]).append('\n');
}
}
sb.append(" --\n");
return sb.toString();
}
}
/**
* Intrinsified during LambdaForm compilation
* (see {@link InvokerBytecodeGenerator#emitLoop(int)}).
*/
@Hidden
static Object loop(BasicType[] localTypes, LoopClauses clauseData, Object... av) throws Throwable {
final MethodHandle[] init = clauseData.clauses[0];
final MethodHandle[] step = clauseData.clauses[1];
final MethodHandle[] pred = clauseData.clauses[2];
final MethodHandle[] fini = clauseData.clauses[3];
int varSize = (int) Stream.of(init).filter(h -> h.type().returnType() != void.class).count();
int nArgs = init[0].type().parameterCount();
Object[] varsAndArgs = new Object[varSize + nArgs];
for (int i = 0, v = 0; i < init.length; ++i) {
MethodHandle ih = init[i];
if (ih.type().returnType() == void.class) {
ih.invokeWithArguments(av);
} else {
varsAndArgs[v++] = ih.invokeWithArguments(av);
}
}
System.arraycopy(av, 0, varsAndArgs, varSize, nArgs);
final int nSteps = step.length;
for (; ; ) {
for (int i = 0, v = 0; i < nSteps; ++i) {
MethodHandle p = pred[i];
MethodHandle s = step[i];
MethodHandle f = fini[i];
if (s.type().returnType() == void.class) {
s.invokeWithArguments(varsAndArgs);
} else {
varsAndArgs[v++] = s.invokeWithArguments(varsAndArgs);
}
if (!(boolean) p.invokeWithArguments(varsAndArgs)) {
return f.invokeWithArguments(varsAndArgs);
}
}
}
}
/**
* This method is bound as the predicate in {@linkplain MethodHandles#countedLoop(MethodHandle, MethodHandle,
* MethodHandle) counting loops}.
*
* @param limit the upper bound of the parameter, statically bound at loop creation time.
* @param counter the counter parameter, passed in during loop execution.
*
* @return whether the counter has reached the limit.
*/
static boolean countedLoopPredicate(int limit, int counter) {
return counter < limit;
}
/**
* This method is bound as the step function in {@linkplain MethodHandles#countedLoop(MethodHandle, MethodHandle,
* MethodHandle) counting loops} to increment the counter.
*
* @param limit the upper bound of the loop counter (ignored).
* @param counter the loop counter.
*
* @return the loop counter incremented by 1.
*/
static int countedLoopStep(int limit, int counter) {
return counter + 1;
}
/**
* This is bound to initialize the loop-local iterator in {@linkplain MethodHandles#iteratedLoop iterating loops}.
*
* @param it the {@link Iterable} over which the loop iterates.
*
* @return an {@link Iterator} over the argument's elements.
*/
static Iterator<?> initIterator(Iterable<?> it) {
return it.iterator();
}
/**
* This method is bound as the predicate in {@linkplain MethodHandles#iteratedLoop iterating loops}.
*
* @param it the iterator to be checked.
*
* @return {@code true} iff there are more elements to iterate over.
*/
static boolean iteratePredicate(Iterator<?> it) {
return it.hasNext();
}
/**
* This method is bound as the step for retrieving the current value from the iterator in {@linkplain
* MethodHandles#iteratedLoop iterating loops}.
*
* @param it the iterator.
*
* @return the next element from the iterator.
*/
static Object iterateNext(Iterator<?> it) {
return it.next();
}
/**
* Makes a {@code try-finally} handle that conforms to the type constraints.
*
* @param target the target to execute in a {@code try-finally} block.
* @param cleanup the cleanup to execute in the {@code finally} block.
* @param rtype the result type of the entire construct.
* @param argTypes the types of the arguments.
*
* @return a handle on the constructed {@code try-finally} block.
*/
static MethodHandle makeTryFinally(MethodHandle target, MethodHandle cleanup, Class<?> rtype, Class<?>[] argTypes) {
MethodType type = MethodType.methodType(rtype, argTypes);
LambdaForm form = makeTryFinallyForm(type.basicType());
// Prepare auxiliary method handles used during LambdaForm interpretation.
// Box arguments and wrap them into Object[]: ValueConversions.array().
MethodType varargsType = type.changeReturnType(Object[].class);
MethodHandle collectArgs = varargsArray(type.parameterCount()).asType(varargsType);
MethodHandle unboxResult = unboxResultHandle(rtype);
BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLL();
BoundMethodHandle mh;
try {
mh = (BoundMethodHandle) data.factory().invokeBasic(type, form, (Object) target, (Object) cleanup,
(Object) collectArgs, (Object) unboxResult);
} catch (Throwable ex) {
throw uncaughtException(ex);
}
assert(mh.type() == type);
return mh;
}
/**
* The LambdaForm shape for the tryFinally combinator is as follows (assuming one reference parameter passed in
* {@code a1}, and a reference return type, with the return value represented by {@code t8}):
* <blockquote><pre>{@code
* tryFinally=Lambda(a0:L,a1:L)=>{
* t2:L=BoundMethodHandle$Species_LLLL.argL0(a0:L); // target method handle
* t3:L=BoundMethodHandle$Species_LLLL.argL1(a0:L); // cleanup method handle
* t4:L=BoundMethodHandle$Species_LLLL.argL2(a0:L); // helper handle to box the arguments into an Object[]
* t5:L=BoundMethodHandle$Species_LLLL.argL3(a0:L); // helper handle to unbox the result
* t6:L=MethodHandle.invokeBasic(t4:L,a1:L); // box the arguments into an Object[]
* t7:L=MethodHandleImpl.tryFinally(t2:L,t3:L,t6:L); // call the tryFinally executor
* t8:L=MethodHandle.invokeBasic(t5:L,t7:L);t8:L} // unbox the result; return the result
* }</pre></blockquote>
* <p>
* {@code argL0} and {@code argL1} are the target and cleanup method handles.
* {@code argL2} and {@code argL3} are auxiliary method handles: {@code argL2} boxes arguments and wraps them into
* {@code Object[]} ({@code ValueConversions.array()}), and {@code argL3} unboxes the result if necessary
* ({@code ValueConversions.unbox()}).
* <p>
* Having {@code t4} and {@code t5} passed in via a BMH and not hardcoded in the lambda form allows to share lambda
* forms among tryFinally combinators with the same basic type.
*/
private static LambdaForm makeTryFinallyForm(MethodType basicType) {
LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_TF);
if (lform != null) {
return lform;
}
final int THIS_MH = 0; // the BMH_LLLL
final int ARG_BASE = 1; // start of incoming arguments
final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
int nameCursor = ARG_LIMIT;
final int GET_TARGET = nameCursor++;
final int GET_CLEANUP = nameCursor++;
final int GET_COLLECT_ARGS = nameCursor++;
final int GET_UNBOX_RESULT = nameCursor++;
final int BOXED_ARGS = nameCursor++;
final int TRY_FINALLY = nameCursor++;
final int UNBOX_RESULT = nameCursor++;
Name[] names = invokeArguments(nameCursor - ARG_LIMIT, basicType);
BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLL();
names[THIS_MH] = names[THIS_MH].withConstraint(data);
names[GET_TARGET] = new Name(data.getterFunction(0), names[THIS_MH]);
names[GET_CLEANUP] = new Name(data.getterFunction(1), names[THIS_MH]);
names[GET_COLLECT_ARGS] = new Name(data.getterFunction(2), names[THIS_MH]);
names[GET_UNBOX_RESULT] = new Name(data.getterFunction(3), names[THIS_MH]);
// t_{i}:L=MethodHandle.invokeBasic(collectArgs:L,a1:L,...);
MethodType collectArgsType = basicType.changeReturnType(Object.class);
MethodHandle invokeBasic = MethodHandles.basicInvoker(collectArgsType);
Object[] args = new Object[invokeBasic.type().parameterCount()];
args[0] = names[GET_COLLECT_ARGS];
System.arraycopy(names, ARG_BASE, args, 1, ARG_LIMIT-ARG_BASE);
names[BOXED_ARGS] = new Name(new NamedFunction(makeIntrinsic(invokeBasic, Intrinsic.TRY_FINALLY)), args);
// t_{i+1}:L=MethodHandleImpl.tryFinally(target:L,exType:L,catcher:L,t_{i}:L);
Object[] tfArgs = new Object[] {names[GET_TARGET], names[GET_CLEANUP], names[BOXED_ARGS]};
names[TRY_FINALLY] = new Name(getFunction(NF_tryFinally), tfArgs);
// t_{i+2}:I=MethodHandle.invokeBasic(unbox:L,t_{i+1}:L);
MethodHandle invokeBasicUnbox = MethodHandles.basicInvoker(MethodType.methodType(basicType.rtype(), Object.class));
Object[] unboxArgs = new Object[] {names[GET_UNBOX_RESULT], names[TRY_FINALLY]};
names[UNBOX_RESULT] = new Name(invokeBasicUnbox, unboxArgs);
lform = LambdaForm.create(basicType.parameterCount() + 1, names, Kind.TRY_FINALLY);
return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_TF, lform);
}
/**
* Intrinsified during LambdaForm compilation
* (see {@link InvokerBytecodeGenerator#emitTryFinally emitTryFinally}).
*/
@Hidden
static Object tryFinally(MethodHandle target, MethodHandle cleanup, Object... av) throws Throwable {
Throwable t = null;
Object r = null;
try {
r = target.invokeWithArguments(av);
} catch (Throwable thrown) {
t = thrown;
throw t;
} finally {
Object[] args = target.type().returnType() == void.class ? prepend(av, t) : prepend(av, t, r);
r = cleanup.invokeWithArguments(args);
}
return r;
}
// see varargsArray method for chaching/package-private version of this
private static MethodHandle makeCollector(Class<?> arrayType, int parameterCount) {
MethodType type = MethodType.methodType(arrayType, Collections.nCopies(parameterCount, arrayType.componentType()));
MethodHandle newArray = MethodHandles.arrayConstructor(arrayType);
LambdaForm form = makeCollectorForm(type.basicType(), arrayType);
BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_L();
BoundMethodHandle mh;
try {
mh = (BoundMethodHandle) data.factory().invokeBasic(type, form, (Object) newArray);
} catch (Throwable ex) {
throw uncaughtException(ex);
}
assert(mh.type() == type);
return mh;
}
private static LambdaForm makeCollectorForm(MethodType basicType, Class<?> arrayType) {
int parameterCount = basicType.parameterCount();
// Only share the lambda form for empty arrays and reference types.
// Sharing based on the basic type alone doesn't work because
// we need a separate lambda form for byte/short/char/int which
// are all erased to int otherwise.
// Other caching for primitive types happens at the MethodHandle level (see varargsArray).
boolean isReferenceType = !arrayType.componentType().isPrimitive();
boolean isSharedLambdaForm = parameterCount == 0 || isReferenceType;
if (isSharedLambdaForm) {
LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_COLLECTOR);
if (lform != null) {
return lform;
}
}
// use erased accessor for reference types
MethodHandle storeFunc = isReferenceType
? ArrayAccessor.OBJECT_ARRAY_SETTER
: makeArrayElementAccessor(arrayType, ArrayAccess.SET);
final int THIS_MH = 0; // the BMH_L
final int ARG_BASE = 1; // start of incoming arguments
final int ARG_LIMIT = ARG_BASE + parameterCount;
int nameCursor = ARG_LIMIT;
final int GET_NEW_ARRAY = nameCursor++;
final int CALL_NEW_ARRAY = nameCursor++;
final int STORE_ELEMENT_BASE = nameCursor;
final int STORE_ELEMENT_LIMIT = STORE_ELEMENT_BASE + parameterCount;
nameCursor = STORE_ELEMENT_LIMIT;
Name[] names = invokeArguments(nameCursor - ARG_LIMIT, basicType);
BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_L();
names[THIS_MH] = names[THIS_MH].withConstraint(data);
names[GET_NEW_ARRAY] = new Name(data.getterFunction(0), names[THIS_MH]);
MethodHandle invokeBasic = MethodHandles.basicInvoker(MethodType.methodType(Object.class, int.class));
names[CALL_NEW_ARRAY] = new Name(new NamedFunction(invokeBasic), names[GET_NEW_ARRAY], parameterCount);
for (int storeIndex = 0,
storeNameCursor = STORE_ELEMENT_BASE,
argCursor = ARG_BASE;
storeNameCursor < STORE_ELEMENT_LIMIT;
storeIndex++, storeNameCursor++, argCursor++){
names[storeNameCursor] = new Name(new NamedFunction(makeIntrinsic(storeFunc, Intrinsic.ARRAY_STORE)),
names[CALL_NEW_ARRAY], storeIndex, names[argCursor]);
}
LambdaForm lform = LambdaForm.create(basicType.parameterCount() + 1, names, CALL_NEW_ARRAY, Kind.COLLECTOR);
if (isSharedLambdaForm) {
lform = basicType.form().setCachedLambdaForm(MethodTypeForm.LF_COLLECTOR, lform);
}
return lform;
}
// use a wrapper because we need this array to be @Stable
static class CasesHolder {
@Stable
final MethodHandle[] cases;
public CasesHolder(MethodHandle[] cases) {
this.cases = cases;
}
}
static MethodHandle makeTableSwitch(MethodType type, MethodHandle defaultCase, MethodHandle[] caseActions) {
MethodType varargsType = type.changeReturnType(Object[].class);
MethodHandle collectArgs = varargsArray(type.parameterCount()).asType(varargsType);
MethodHandle unboxResult = unboxResultHandle(type.returnType());
BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLL();
LambdaForm form = makeTableSwitchForm(type.basicType(), data, caseActions.length);
BoundMethodHandle mh;
CasesHolder caseHolder = new CasesHolder(caseActions);
try {
mh = (BoundMethodHandle) data.factory().invokeBasic(type, form, (Object) defaultCase, (Object) collectArgs,
(Object) unboxResult, (Object) caseHolder);
} catch (Throwable ex) {
throw uncaughtException(ex);
}
assert(mh.type() == type);
return mh;
}
private static class TableSwitchCacheKey {
private static final Map<TableSwitchCacheKey, LambdaForm> CACHE = new ConcurrentHashMap<>();
private final MethodType basicType;
private final int numberOfCases;
public TableSwitchCacheKey(MethodType basicType, int numberOfCases) {
this.basicType = basicType;
this.numberOfCases = numberOfCases;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
TableSwitchCacheKey that = (TableSwitchCacheKey) o;
return numberOfCases == that.numberOfCases && Objects.equals(basicType, that.basicType);
}
@Override
public int hashCode() {
return Objects.hash(basicType, numberOfCases);
}
}
private static LambdaForm makeTableSwitchForm(MethodType basicType, BoundMethodHandle.SpeciesData data,
int numCases) {
// We need to cache based on the basic type X number of cases,
// since the number of cases is used when generating bytecode.
// This also means that we can't use the cache in MethodTypeForm,
// which only uses the basic type as a key.
TableSwitchCacheKey key = new TableSwitchCacheKey(basicType, numCases);
LambdaForm lform = TableSwitchCacheKey.CACHE.get(key);
if (lform != null) {
return lform;
}
final int THIS_MH = 0;
final int ARG_BASE = 1; // start of incoming arguments
final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
final int ARG_SWITCH_ON = ARG_BASE;
assert ARG_SWITCH_ON < ARG_LIMIT;
int nameCursor = ARG_LIMIT;
final int GET_COLLECT_ARGS = nameCursor++;
final int GET_DEFAULT_CASE = nameCursor++;
final int GET_UNBOX_RESULT = nameCursor++;
final int GET_CASES = nameCursor++;
final int BOXED_ARGS = nameCursor++;
final int TABLE_SWITCH = nameCursor++;
final int UNBOXED_RESULT = nameCursor++;
int fieldCursor = 0;
final int FIELD_DEFAULT_CASE = fieldCursor++;
final int FIELD_COLLECT_ARGS = fieldCursor++;
final int FIELD_UNBOX_RESULT = fieldCursor++;
final int FIELD_CASES = fieldCursor++;
Name[] names = invokeArguments(nameCursor - ARG_LIMIT, basicType);
names[THIS_MH] = names[THIS_MH].withConstraint(data);
names[GET_DEFAULT_CASE] = new Name(data.getterFunction(FIELD_DEFAULT_CASE), names[THIS_MH]);
names[GET_COLLECT_ARGS] = new Name(data.getterFunction(FIELD_COLLECT_ARGS), names[THIS_MH]);
names[GET_UNBOX_RESULT] = new Name(data.getterFunction(FIELD_UNBOX_RESULT), names[THIS_MH]);
names[GET_CASES] = new Name(data.getterFunction(FIELD_CASES), names[THIS_MH]);
{
MethodType collectArgsType = basicType.changeReturnType(Object.class);
MethodHandle invokeBasic = MethodHandles.basicInvoker(collectArgsType);
Object[] args = new Object[invokeBasic.type().parameterCount()];
args[0] = names[GET_COLLECT_ARGS];
System.arraycopy(names, ARG_BASE, args, 1, ARG_LIMIT - ARG_BASE);
names[BOXED_ARGS] = new Name(new NamedFunction(makeIntrinsic(invokeBasic, Intrinsic.TABLE_SWITCH, numCases)), args);
}
{
Object[] tfArgs = new Object[]{
names[ARG_SWITCH_ON], names[GET_DEFAULT_CASE], names[GET_CASES], names[BOXED_ARGS]};
names[TABLE_SWITCH] = new Name(getFunction(NF_tableSwitch), tfArgs);
}
{
MethodHandle invokeBasic = MethodHandles.basicInvoker(MethodType.methodType(basicType.rtype(), Object.class));
Object[] unboxArgs = new Object[]{names[GET_UNBOX_RESULT], names[TABLE_SWITCH]};
names[UNBOXED_RESULT] = new Name(invokeBasic, unboxArgs);
}
lform = LambdaForm.create(basicType.parameterCount() + 1, names, Kind.TABLE_SWITCH);
LambdaForm prev = TableSwitchCacheKey.CACHE.putIfAbsent(key, lform);
return prev != null ? prev : lform;
}
@Hidden
static Object tableSwitch(int input, MethodHandle defaultCase, CasesHolder holder, Object[] args) throws Throwable {
MethodHandle[] caseActions = holder.cases;
MethodHandle selectedCase;
if (input < 0 || input >= caseActions.length) {
selectedCase = defaultCase;
} else {
selectedCase = caseActions[input];
}
return selectedCase.invokeWithArguments(args);
}
// type is validated, value is not
static MethodHandle makeConstantReturning(Class<?> type, Object value) {
var callType = MethodType.methodType(type);
var basicType = BasicType.basicType(type);
var form = constantForm(basicType);
if (type.isPrimitive()) {
assert type != void.class;
var wrapper = Wrapper.forPrimitiveType(type);
var v = wrapper.convert(value, type); // throws CCE
return switch (wrapper) {
case INT -> BoundMethodHandle.bindSingleI(callType, form, (int) v);
case LONG -> BoundMethodHandle.bindSingleJ(callType, form, (long) v);
case FLOAT -> BoundMethodHandle.bindSingleF(callType, form, (float) v);
case DOUBLE -> BoundMethodHandle.bindSingleD(callType, form, (double) v);
default -> BoundMethodHandle.bindSingleI(callType, form, ValueConversions.widenSubword(v));
};
}
var v = type.cast(value); // throws CCE
return BoundMethodHandle.bindSingleL(callType, form, v);
}
// Indexes into constant method handles:
static final int
MH_cast = 0,
MH_selectAlternative = 1,
MH_countedLoopPred = 2,
MH_countedLoopStep = 3,
MH_initIterator = 4,
MH_iteratePred = 5,
MH_iterateNext = 6,
MH_Array_newInstance = 7,
MH_VarHandles_handleCheckedExceptions = 8,
MH_LIMIT = 9;
static MethodHandle getConstantHandle(int idx) {
MethodHandle handle = HANDLES[idx];
if (handle != null) {
return handle;
}
return setCachedHandle(idx, makeConstantHandle(idx));
}
private static synchronized MethodHandle setCachedHandle(int idx, final MethodHandle method) {
// Simulate a CAS, to avoid racy duplication of results.
MethodHandle prev = HANDLES[idx];
if (prev != null) {
return prev;
}
HANDLES[idx] = method;
return method;
}
// Local constant method handles:
private static final @Stable MethodHandle[] HANDLES = new MethodHandle[MH_LIMIT];
private static MethodHandle makeConstantHandle(int idx) {
try {
switch (idx) {
case MH_cast:
return IMPL_LOOKUP.findVirtual(Class.class, "cast",
MethodType.methodType(Object.class, Object.class));
case MH_selectAlternative:
return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "selectAlternative",
MethodType.methodType(MethodHandle.class, boolean.class, MethodHandle.class, MethodHandle.class));
case MH_countedLoopPred:
return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "countedLoopPredicate",
MethodType.methodType(boolean.class, int.class, int.class));
case MH_countedLoopStep:
return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "countedLoopStep",
MethodType.methodType(int.class, int.class, int.class));
case MH_initIterator:
return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "initIterator",
MethodType.methodType(Iterator.class, Iterable.class));
case MH_iteratePred:
return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "iteratePredicate",
MethodType.methodType(boolean.class, Iterator.class));
case MH_iterateNext:
return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "iterateNext",
MethodType.methodType(Object.class, Iterator.class));
case MH_Array_newInstance:
return IMPL_LOOKUP.findStatic(Array.class, "newInstance",
MethodType.methodType(Object.class, Class.class, int.class));
case MH_VarHandles_handleCheckedExceptions:
return IMPL_LOOKUP.findStatic(VarHandles.class, "handleCheckedExceptions",
MethodType.methodType(void.class, Throwable.class));
}
} catch (ReflectiveOperationException ex) {
throw newInternalError(ex);
}
throw newInternalError("Unknown function index: " + idx);
}
}