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The Qbicc builder for the java.base JDK module
/*
* Copyright (c) 2017, 2021, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.lang.runtime;
import java.lang.invoke.ConstantCallSite;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import java.lang.invoke.TypeDescriptor;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Objects;
/**
* Bootstrap methods for state-driven implementations of core methods,
* including {@link Object#equals(Object)}, {@link Object#hashCode()}, and
* {@link Object#toString()}. These methods may be used, for example, by
* Java compiler implementations to implement the bodies of {@link Object}
* methods for record classes.
*
* @since 16
*/
public class ObjectMethods {
private ObjectMethods() { }
private static final MethodType DESCRIPTOR_MT = MethodType.methodType(MethodType.class);
private static final MethodType NAMES_MT = MethodType.methodType(List.class);
private static final MethodHandle FALSE = MethodHandles.constant(boolean.class, false);
private static final MethodHandle TRUE = MethodHandles.constant(boolean.class, true);
private static final MethodHandle ZERO = MethodHandles.constant(int.class, 0);
private static final MethodHandle CLASS_IS_INSTANCE;
private static final MethodHandle OBJECT_EQUALS;
private static final MethodHandle OBJECTS_EQUALS;
private static final MethodHandle OBJECTS_HASHCODE;
private static final MethodHandle OBJECTS_TOSTRING;
private static final MethodHandle OBJECT_EQ;
private static final MethodHandle OBJECT_HASHCODE;
private static final MethodHandle OBJECT_TO_STRING;
private static final MethodHandle STRING_FORMAT;
private static final MethodHandle HASH_COMBINER;
private static final HashMap, MethodHandle> primitiveEquals = new HashMap<>();
private static final HashMap, MethodHandle> primitiveHashers = new HashMap<>();
private static final HashMap, MethodHandle> primitiveToString = new HashMap<>();
static {
try {
Class OBJECT_METHODS_CLASS = ObjectMethods.class;
MethodHandles.Lookup publicLookup = MethodHandles.publicLookup();
MethodHandles.Lookup lookup = MethodHandles.lookup();
@SuppressWarnings("removal")
ClassLoader loader = AccessController.doPrivileged(new PrivilegedAction() {
@Override public ClassLoader run() { return ClassLoader.getPlatformClassLoader(); }
});
CLASS_IS_INSTANCE = publicLookup.findVirtual(Class.class, "isInstance",
MethodType.methodType(boolean.class, Object.class));
OBJECT_EQUALS = publicLookup.findVirtual(Object.class, "equals",
MethodType.methodType(boolean.class, Object.class));
OBJECT_HASHCODE = publicLookup.findVirtual(Object.class, "hashCode",
MethodType.fromMethodDescriptorString("()I", loader));
OBJECT_TO_STRING = publicLookup.findVirtual(Object.class, "toString",
MethodType.methodType(String.class));
STRING_FORMAT = publicLookup.findStatic(String.class, "format",
MethodType.methodType(String.class, String.class, Object[].class));
OBJECTS_EQUALS = publicLookup.findStatic(Objects.class, "equals",
MethodType.methodType(boolean.class, Object.class, Object.class));
OBJECTS_HASHCODE = publicLookup.findStatic(Objects.class, "hashCode",
MethodType.methodType(int.class, Object.class));
OBJECTS_TOSTRING = publicLookup.findStatic(Objects.class, "toString",
MethodType.methodType(String.class, Object.class));
OBJECT_EQ = lookup.findStatic(OBJECT_METHODS_CLASS, "eq",
MethodType.methodType(boolean.class, Object.class, Object.class));
HASH_COMBINER = lookup.findStatic(OBJECT_METHODS_CLASS, "hashCombiner",
MethodType.fromMethodDescriptorString("(II)I", loader));
primitiveEquals.put(byte.class, lookup.findStatic(OBJECT_METHODS_CLASS, "eq",
MethodType.fromMethodDescriptorString("(BB)Z", loader)));
primitiveEquals.put(short.class, lookup.findStatic(OBJECT_METHODS_CLASS, "eq",
MethodType.fromMethodDescriptorString("(SS)Z", loader)));
primitiveEquals.put(char.class, lookup.findStatic(OBJECT_METHODS_CLASS, "eq",
MethodType.fromMethodDescriptorString("(CC)Z", loader)));
primitiveEquals.put(int.class, lookup.findStatic(OBJECT_METHODS_CLASS, "eq",
MethodType.fromMethodDescriptorString("(II)Z", loader)));
primitiveEquals.put(long.class, lookup.findStatic(OBJECT_METHODS_CLASS, "eq",
MethodType.fromMethodDescriptorString("(JJ)Z", loader)));
primitiveEquals.put(float.class, lookup.findStatic(OBJECT_METHODS_CLASS, "eq",
MethodType.fromMethodDescriptorString("(FF)Z", loader)));
primitiveEquals.put(double.class, lookup.findStatic(OBJECT_METHODS_CLASS, "eq",
MethodType.fromMethodDescriptorString("(DD)Z", loader)));
primitiveEquals.put(boolean.class, lookup.findStatic(OBJECT_METHODS_CLASS, "eq",
MethodType.fromMethodDescriptorString("(ZZ)Z", loader)));
primitiveHashers.put(byte.class, lookup.findStatic(Byte.class, "hashCode",
MethodType.fromMethodDescriptorString("(B)I", loader)));
primitiveHashers.put(short.class, lookup.findStatic(Short.class, "hashCode",
MethodType.fromMethodDescriptorString("(S)I", loader)));
primitiveHashers.put(char.class, lookup.findStatic(Character.class, "hashCode",
MethodType.fromMethodDescriptorString("(C)I", loader)));
primitiveHashers.put(int.class, lookup.findStatic(Integer.class, "hashCode",
MethodType.fromMethodDescriptorString("(I)I", loader)));
primitiveHashers.put(long.class, lookup.findStatic(Long.class, "hashCode",
MethodType.fromMethodDescriptorString("(J)I", loader)));
primitiveHashers.put(float.class, lookup.findStatic(Float.class, "hashCode",
MethodType.fromMethodDescriptorString("(F)I", loader)));
primitiveHashers.put(double.class, lookup.findStatic(Double.class, "hashCode",
MethodType.fromMethodDescriptorString("(D)I", loader)));
primitiveHashers.put(boolean.class, lookup.findStatic(Boolean.class, "hashCode",
MethodType.fromMethodDescriptorString("(Z)I", loader)));
primitiveToString.put(byte.class, lookup.findStatic(Byte.class, "toString",
MethodType.methodType(String.class, byte.class)));
primitiveToString.put(short.class, lookup.findStatic(Short.class, "toString",
MethodType.methodType(String.class, short.class)));
primitiveToString.put(char.class, lookup.findStatic(Character.class, "toString",
MethodType.methodType(String.class, char.class)));
primitiveToString.put(int.class, lookup.findStatic(Integer.class, "toString",
MethodType.methodType(String.class, int.class)));
primitiveToString.put(long.class, lookup.findStatic(Long.class, "toString",
MethodType.methodType(String.class, long.class)));
primitiveToString.put(float.class, lookup.findStatic(Float.class, "toString",
MethodType.methodType(String.class, float.class)));
primitiveToString.put(double.class, lookup.findStatic(Double.class, "toString",
MethodType.methodType(String.class, double.class)));
primitiveToString.put(boolean.class, lookup.findStatic(Boolean.class, "toString",
MethodType.methodType(String.class, boolean.class)));
}
catch (ReflectiveOperationException e) {
throw new RuntimeException(e);
}
}
private static int hashCombiner(int x, int y) {
return x*31 + y;
}
private static boolean eq(Object a, Object b) { return a == b; }
private static boolean eq(byte a, byte b) { return a == b; }
private static boolean eq(short a, short b) { return a == b; }
private static boolean eq(char a, char b) { return a == b; }
private static boolean eq(int a, int b) { return a == b; }
private static boolean eq(long a, long b) { return a == b; }
private static boolean eq(float a, float b) { return Float.compare(a, b) == 0; }
private static boolean eq(double a, double b) { return Double.compare(a, b) == 0; }
private static boolean eq(boolean a, boolean b) { return a == b; }
/** Get the method handle for combining two values of a given type */
private static MethodHandle equalator(Class clazz) {
return (clazz.isPrimitive()
? primitiveEquals.get(clazz)
: OBJECTS_EQUALS.asType(MethodType.methodType(boolean.class, clazz, clazz)));
}
/** Get the hasher for a value of a given type */
private static MethodHandle hasher(Class clazz) {
return (clazz.isPrimitive()
? primitiveHashers.get(clazz)
: OBJECTS_HASHCODE.asType(MethodType.methodType(int.class, clazz)));
}
/** Get the stringifier for a value of a given type */
private static MethodHandle stringifier(Class clazz) {
return (clazz.isPrimitive()
? primitiveToString.get(clazz)
: OBJECTS_TOSTRING.asType(MethodType.methodType(String.class, clazz)));
}
/**
* Generates a method handle for the {@code equals} method for a given data class
* @param receiverClass the data class
* @param getters the list of getters
* @return the method handle
*/
private static MethodHandle makeEquals(Class receiverClass,
List getters) {
MethodType rr = MethodType.methodType(boolean.class, receiverClass, receiverClass);
MethodType ro = MethodType.methodType(boolean.class, receiverClass, Object.class);
MethodHandle instanceFalse = MethodHandles.dropArguments(FALSE, 0, receiverClass, Object.class); // (RO)Z
MethodHandle instanceTrue = MethodHandles.dropArguments(TRUE, 0, receiverClass, Object.class); // (RO)Z
MethodHandle isSameObject = OBJECT_EQ.asType(ro); // (RO)Z
MethodHandle isInstance = MethodHandles.dropArguments(CLASS_IS_INSTANCE.bindTo(receiverClass), 0, receiverClass); // (RO)Z
MethodHandle accumulator = MethodHandles.dropArguments(TRUE, 0, receiverClass, receiverClass); // (RR)Z
for (MethodHandle getter : getters) {
MethodHandle equalator = equalator(getter.type().returnType()); // (TT)Z
MethodHandle thisFieldEqual = MethodHandles.filterArguments(equalator, 0, getter, getter); // (RR)Z
accumulator = MethodHandles.guardWithTest(thisFieldEqual, accumulator, instanceFalse.asType(rr));
}
return MethodHandles.guardWithTest(isSameObject,
instanceTrue,
MethodHandles.guardWithTest(isInstance, accumulator.asType(ro), instanceFalse));
}
/**
* Generates a method handle for the {@code hashCode} method for a given data class
* @param receiverClass the data class
* @param getters the list of getters
* @return the method handle
*/
private static MethodHandle makeHashCode(Class receiverClass,
List getters) {
MethodHandle accumulator = MethodHandles.dropArguments(ZERO, 0, receiverClass); // (R)I
// @@@ Use loop combinator instead?
for (MethodHandle getter : getters) {
MethodHandle hasher = hasher(getter.type().returnType()); // (T)I
MethodHandle hashThisField = MethodHandles.filterArguments(hasher, 0, getter); // (R)I
MethodHandle combineHashes = MethodHandles.filterArguments(HASH_COMBINER, 0, accumulator, hashThisField); // (RR)I
accumulator = MethodHandles.permuteArguments(combineHashes, accumulator.type(), 0, 0); // adapt (R)I to (RR)I
}
return accumulator;
}
/**
* Generates a method handle for the {@code toString} method for a given data class
* @param receiverClass the data class
* @param getters the list of getters
* @param names the names
* @return the method handle
*/
private static MethodHandle makeToString(Class receiverClass,
List getters,
List names) {
// This is a pretty lousy algorithm; we spread the receiver over N places,
// apply the N getters, apply N toString operations, and concat the result with String.format
// Better to use String.format directly, or delegate to StringConcatFactory
// Also probably want some quoting around String components
assert getters.size() == names.size();
int[] invArgs = new int[getters.size()];
Arrays.fill(invArgs, 0);
MethodHandle[] filters = new MethodHandle[getters.size()];
StringBuilder sb = new StringBuilder();
sb.append(receiverClass.getSimpleName()).append("[");
for (int i=0; i recordClass,
String names,
MethodHandle... getters) throws Throwable {
MethodType methodType;
if (type instanceof MethodType)
methodType = (MethodType) type;
else {
methodType = null;
if (!MethodHandle.class.equals(type))
throw new IllegalArgumentException(type.toString());
}
List getterList = List.of(getters);
MethodHandle handle = switch (methodName) {
case "equals" -> {
if (methodType != null && !methodType.equals(MethodType.methodType(boolean.class, recordClass, Object.class)))
throw new IllegalArgumentException("Bad method type: " + methodType);
yield makeEquals(recordClass, getterList);
}
case "hashCode" -> {
if (methodType != null && !methodType.equals(MethodType.methodType(int.class, recordClass)))
throw new IllegalArgumentException("Bad method type: " + methodType);
yield makeHashCode(recordClass, getterList);
}
case "toString" -> {
if (methodType != null && !methodType.equals(MethodType.methodType(String.class, recordClass)))
throw new IllegalArgumentException("Bad method type: " + methodType);
List nameList = "".equals(names) ? List.of() : List.of(names.split(";"));
if (nameList.size() != getterList.size())
throw new IllegalArgumentException("Name list and accessor list do not match");
yield makeToString(recordClass, getterList, nameList);
}
default -> throw new IllegalArgumentException(methodName);
};
return methodType != null ? new ConstantCallSite(handle) : handle;
}
}
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