jdk-sandbox: comparison src/java.base/share/classes/java/lang/invoke/ClassSpecializer.java

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-:e0041b182e31
+:a2008587c13f
+/*
+* Copyright (c) 2017, 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.invoke;
+import jdk.internal.loader.BootLoader;
+import jdk.internal.org.objectweb.asm.ClassWriter;
+import jdk.internal.org.objectweb.asm.FieldVisitor;
+import jdk.internal.org.objectweb.asm.MethodVisitor;
+import jdk.internal.vm.annotation.Stable;
+import sun.invoke.util.BytecodeName;
+import java.lang.reflect.*;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.security.ProtectionDomain;
+import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.function.Function;
+import static java.lang.invoke.LambdaForm.*;
+import static java.lang.invoke.MethodHandleNatives.Constants.REF_getStatic;
+import static java.lang.invoke.MethodHandleNatives.Constants.REF_putStatic;
+import static java.lang.invoke.MethodHandleStatics.*;
+import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
+import static jdk.internal.org.objectweb.asm.Opcodes.*;
+/**
+* Class specialization code.
+* @param <T> top class under which species classes are created.
+* @param <K> key which identifies individual specializations.
+* @param <S> species data type.
+*/
+/*non-public*/
+abstract class ClassSpecializer<T,K,S extends ClassSpecializer<T,K,S>.SpeciesData> {
+private final Class<T> topClass;
+private final Class<K> keyType;
+private final Class<S> metaType;
+private final MemberName sdAccessor;
+private final String sdFieldName;
+private final List<MemberName> transformMethods;
+private final MethodType baseConstructorType;
+private final S topSpecies;
+private final ConcurrentMap<K, S> cache = new ConcurrentHashMap<>();
+private final Factory factory;
+private @Stable boolean topClassIsSuper;
+/** Return the top type mirror, for type {@code T} */
+public final Class<T> topClass() { return topClass; }
+/** Return the key type mirror, for type {@code K} */
+public final Class<K> keyType() { return keyType; }
+/** Return the species metadata type mirror, for type {@code S} */
+public final Class<S> metaType() { return metaType; }
+/** Report the leading arguments (if any) required by every species factory.
+* Every species factory adds its own field types as additional arguments,
+* but these arguments always come first, in every factory method.
+*/
+protected MethodType baseConstructorType() { return baseConstructorType; }
+/** Return the trivial species for the null sequence of arguments. */
+protected final S topSpecies() { return topSpecies; }
+/** Return the list of transform methods originally given at creation of this specializer. */
+protected final List<MemberName> transformMethods() { return transformMethods; }
+/** Return the factory object used to build and load concrete species code. */
+protected final Factory factory() { return factory; }
+/**
+* Constructor for this class specializer.
+* @param topClass type mirror for T
+* @param keyType type mirror for K
+* @param metaType type mirror for S
+* @param baseConstructorType principal constructor type
+* @param sdAccessor the method used to get the speciesData
+* @param sdFieldName the name of the species data field, inject the speciesData object
+* @param transformMethods optional list of transformMethods
+*/
+protected ClassSpecializer(Class<T> topClass,
+Class<K> keyType,
+Class<S> metaType,
+MethodType baseConstructorType,
+MemberName sdAccessor,
+String sdFieldName,
+List<MemberName> transformMethods) {
+this.topClass = topClass;
+this.keyType = keyType;
+this.metaType = metaType;
+this.sdAccessor = sdAccessor;
+// FIXME: use List.copyOf once 8177290 is in
+this.transformMethods = List.of(transformMethods.toArray(new MemberName[transformMethods.size()]));
+this.sdFieldName = sdFieldName;
+this.baseConstructorType = baseConstructorType.changeReturnType(void.class);
+this.factory = makeFactory();
+K tsk = topSpeciesKey();
+S topSpecies = null;
+if (tsk != null && topSpecies == null) {
+// if there is a key, build the top species if needed:
+topSpecies = findSpecies(tsk);
+}
+this.topSpecies = topSpecies;
+}
+// Utilities for subclass constructors:
+protected static <T> Constructor<T> reflectConstructor(Class<T> defc, Class<?>... ptypes) {
+try {
+return defc.getDeclaredConstructor(ptypes);
+} catch (NoSuchMethodException ex) {
+throw newIAE(defc.getName()+"("+MethodType.methodType(void.class, ptypes)+")", ex);
+}
+}
+protected static Field reflectField(Class<?> defc, String name) {
+try {
+return defc.getDeclaredField(name);
+} catch (NoSuchFieldException ex) {
+throw newIAE(defc.getName()+"."+name, ex);
+}
+}
+private static RuntimeException newIAE(String message, Throwable cause) {
+return new IllegalArgumentException(message, cause);
+}
+public final S findSpecies(K key) {
+S speciesData = cache.computeIfAbsent(key, new Function<>() {
+@Override
+public S apply(K key1) {
+return factory.loadSpecies(newSpeciesData(key1));
+}
+});
+// Note:  Species instantiation may throw VirtualMachineError because of
+// code cache overflow.  If this happens the species bytecode may be
+// loaded but not linked to its species metadata (with MH's etc).
+// That will cause a throw out of CHM.computeIfAbsent,
+// which will shut down the caller thread.
+//
+// In a latter attempt to get the same species, the already-loaded
+// class will be present in the system dictionary, causing an
+// error when the species generator tries to reload it.
+// We try to detect this case and link the pre-existing code.
+//
+// Although it would be better to start fresh by loading a new
+// copy, we have to salvage the previously loaded but broken code.
+// (As an alternative, we might spin a new class with a new name,
+// or use the anonymous class mechanism.)
+//
+// In the end, as long as everybody goes through the same CHM,
+// CHM.computeIfAbsent will ensure only one SpeciesData will be set
+// successfully on a concrete class if ever.
+// The concrete class is published via SpeciesData instance
+// returned here only after the class and species data are linked together.
+assert(speciesData != null);
+return speciesData;
+}
+/**
+* Meta-data wrapper for concrete subtypes of the top class.
+* Each concrete subtype corresponds to a given sequence of basic field types (LIJFD).
+* The fields are immutable; their values are fully specified at object construction.
+* Each species supplies an array of getter functions which may be used in lambda forms.
+* A concrete value is always constructed from the full tuple of its field values,
+* accompanied by the required constructor parameters.
+* There *may* also be transforms which cloning a species instance and
+* either replace a constructor parameter or add one or more new field values.
+* The shortest possible species has zero fields.
+* Subtypes are not interrelated among themselves by subtyping, even though
+* it would appear that a shorter species could serve as a supertype of a
+* longer one which extends it.
+*/
+public abstract class SpeciesData {
+// Bootstrapping requires circular relations Class -> SpeciesData -> Class
+// Therefore, we need non-final links in the chain.  Use @Stable fields.
+private final K key;
+private final List<Class<?>> fieldTypes;
+@Stable private Class<? extends T> speciesCode;
+@Stable private List<MethodHandle> factories;
+@Stable private List<MethodHandle> getters;
+@Stable private List<LambdaForm.NamedFunction> nominalGetters;
+@Stable private final MethodHandle[] transformHelpers = new MethodHandle[transformMethods.size()];
+protected SpeciesData(K key) {
+this.key = keyType.cast(Objects.requireNonNull(key));
+List<Class<?>> types = deriveFieldTypes(key);
+// TODO: List.copyOf
+int arity = types.size();
+this.fieldTypes = List.of(types.toArray(new Class<?>[arity]));
+}
+public final K key() {
+return key;
+}
+protected final List<Class<?>> fieldTypes() {
+return fieldTypes;
+}
+protected final int fieldCount() {
+return fieldTypes.size();
+}
+protected ClassSpecializer<T,K,S> outer() {
+return ClassSpecializer.this;
+}
+protected final boolean isResolved() {
+return speciesCode != null && factories != null && !factories.isEmpty();
+}
+@Override public String toString() {
+return metaType.getSimpleName() + "[" + key.toString() + " => " + (isResolved() ? speciesCode.getSimpleName() : "UNRESOLVED") + "]";
+}
+@Override
+public int hashCode() {
+return key.hashCode();
+}
+@Override
+public boolean equals(Object obj) {
+if (!(obj instanceof ClassSpecializer.SpeciesData)) {
+return false;
+}
+@SuppressWarnings("rawtypes")
+ClassSpecializer.SpeciesData that = (ClassSpecializer.SpeciesData) obj;
+return this.outer() == that.outer() && this.key.equals(that.key);
+}
+/** Throws NPE if this species is not yet resolved. */
+protected final Class<? extends T> speciesCode() {
+return Objects.requireNonNull(speciesCode);
+}
+/**
+* Return a {@link MethodHandle} which can get the indexed field of this species.
+* The return type is the type of the species field it accesses.
+* The argument type is the {@code fieldHolder} class of this species.
+*/
+protected MethodHandle getter(int i) {
+return getters.get(i);
+}
+/**
+* Return a {@link LambdaForm.Name} containing a {@link LambdaForm.NamedFunction} that
+* represents a MH bound to a generic invoker, which in turn forwards to the corresponding
+* getter.
+*/
+protected LambdaForm.NamedFunction getterFunction(int i) {
+LambdaForm.NamedFunction nf = nominalGetters.get(i);
+assert(nf.memberDeclaringClassOrNull() == speciesCode());
+assert(nf.returnType() == BasicType.basicType(fieldTypes.get(i)));
+return nf;
+}
+protected List<LambdaForm.NamedFunction> getterFunctions() {
+return nominalGetters;
+}
+protected List<MethodHandle> getters() {
+return getters;
+}
+protected MethodHandle factory() {
+return factories.get(0);
+}
+protected MethodHandle transformHelper(int whichtm) {
+MethodHandle mh = transformHelpers[whichtm];
+if (mh != null)  return mh;
+mh = deriveTransformHelper(transformMethods().get(whichtm), whichtm);
+// Do a little type checking before we start using the MH.
+// (It will be called with invokeBasic, so this is our only chance.)
+final MethodType mt = transformHelperType(whichtm);
+mh = mh.asType(mt);
+return transformHelpers[whichtm] = mh;
+}
+private final MethodType transformHelperType(int whichtm) {
+MemberName tm = transformMethods().get(whichtm);
+ArrayList<Class<?>> args = new ArrayList<>();
+ArrayList<Class<?>> fields = new ArrayList<>();
+Collections.addAll(args, tm.getParameterTypes());
+fields.addAll(fieldTypes());
+List<Class<?>> helperArgs = deriveTransformHelperArguments(tm, whichtm, args, fields);
+return MethodType.methodType(tm.getReturnType(), helperArgs);
+}
+// Hooks for subclasses:
+/**
+* Given a key, derive the list of field types, which all instances of this
+* species must store.
+*/
+protected abstract List<Class<?>> deriveFieldTypes(K key);
+/**
+* Given the index of a method in the transforms list, supply a factory
+* method that takes the arguments of the transform, plus the local fields,
+* and produce a value of the required type.
+* You can override this to return null or throw if there are no transforms.
+* This method exists so that the transforms can be "grown" lazily.
+* This is necessary if the transform *adds* a field to an instance,
+* which sometimtes requires the creation, on the fly, of an extended species.
+* This method is only called once for any particular parameter.
+* The species caches the result in a private array.
+*
+* @param transform the transform being implemented
+* @param whichtm the index of that transform in the original list of transforms
+* @return the method handle which creates a new result from a mix of transform
+* arguments and field values
+*/
+protected abstract MethodHandle deriveTransformHelper(MemberName transform, int whichtm);
+/**
+* During code generation, this method is called once per transform to determine
+* what is the mix of arguments to hand to the transform-helper.  The bytecode
+* which marshals these arguments is open-coded in the species-specific transform.
+* The two lists are of opaque objects, which you shouldn't do anything with besides
+* reordering them into the output list.  (They are both mutable, to make editing
+* easier.)  The imputed types of the args correspond to the transform's parameter
+* list, while the imputed types of the fields correspond to the species field types.
+* After code generation, this method may be called occasionally by error-checking code.
+*
+* @param transform the transform being implemented
+* @param whichtm the index of that transform in the original list of transforms
+* @param args a list of opaque objects representing the incoming transform arguments
+* @param fields a list of opaque objects representing the field values of the receiver
+* @param <X> the common element type of the various lists
+* @return a new list
+*/
+protected abstract <X> List<X> deriveTransformHelperArguments(MemberName transform, int whichtm,
+List<X> args, List<X> fields);
+/** Given a key, generate the name of the class which implements the species for that key.
+* This algorithm must be stable.
+*
+* @return class name, which by default is {@code outer().topClass().getName() + "$Species_" + deriveTypeString(key)}
+*/
+protected String deriveClassName() {
+return outer().topClass().getName() + "$Species_" + deriveTypeString();
+}
+/**
+* Default implementation collects basic type characters,
+* plus possibly type names, if some types don't correspond
+* to basic types.
+*
+* @return a string suitable for use in a class name
+*/
+protected String deriveTypeString() {
+List<Class<?>> types = fieldTypes();
+StringBuilder buf = new StringBuilder();
+StringBuilder end = new StringBuilder();
+for (Class<?> type : types) {
+BasicType basicType = BasicType.basicType(type);
+if (basicType.basicTypeClass() == type) {
+buf.append(basicType.basicTypeChar());
+} else {
+buf.append('V');
+end.append(classSig(type));
+}
+}
+String typeString;
+if (end.length() > 0) {
+typeString = BytecodeName.toBytecodeName(buf.append("_").append(end).toString());
+} else {
+typeString = buf.toString();
+}
+return LambdaForm.shortenSignature(typeString);
+}
+/**
+* Report what immediate super-class to use for the concrete class of this species.
+* Normally this is {@code topClass}, but if that is an interface, the factory must override.
+* The super-class must provide a constructor which takes the {@code baseConstructorType} arguments, if any.
+* This hook also allows the code generator to use more than one canned supertype for species.
+*
+* @return the super-class of the class to be generated
+*/
+protected Class<? extends T> deriveSuperClass() {
+final Class<T> topc = topClass();
+if (!topClassIsSuper) {
+try {
+final Constructor<T> con = reflectConstructor(topc, baseConstructorType().parameterArray());
+if (!topc.isInterface() && !Modifier.isPrivate(con.getModifiers())) {
+topClassIsSuper = true;
+}
+} catch (Exception|InternalError ex) {
+// fall through...
+}
+if (!topClassIsSuper) {
+throw newInternalError("must override if the top class cannot serve as a super class");
+}
+}
+return topc;
+}
+}
+protected abstract S newSpeciesData(K key);
+protected K topSpeciesKey() {
+return null;  // null means don't report a top species
+}
+/**
+* Code generation support for instances.
+* Subclasses can modify the behavior.
+*/
+public class Factory {
+/**
+* Get a concrete subclass of the top class for a given combination of bound types.
+*
+* @param speciesData the species requiring the class, not yet linked
+* @return a linked version of the same species
+*/
+S loadSpecies(S speciesData) {
+String className = speciesData.deriveClassName();
+assert(className.indexOf('/') < 0) : className;
+Class<?> salvage = null;
+try {
+salvage = BootLoader.loadClassOrNull(className);
+if (TRACE_RESOLVE && salvage != null) {
+// Used by jlink species pregeneration plugin, see
+// jdk.tools.jlink.internal.plugins.GenerateJLIClassesPlugin
+System.out.println("[SPECIES_RESOLVE] " + className + " (salvaged)");
+}
+} catch (Error ex) {
+if (TRACE_RESOLVE) {
+System.out.println("[SPECIES_FRESOLVE] " + className + " (Error) " + ex.getMessage());
+}
+}
+final Class<? extends T> speciesCode;
+if (salvage != null) {
+speciesCode = salvage.asSubclass(topClass());
+factory.linkSpeciesDataToCode(speciesData, speciesCode);
+factory.linkCodeToSpeciesData(speciesCode, speciesData, true);
+} else {
+// Not pregenerated, generate the class
+try {
+speciesCode = generateConcreteSpeciesCode(className, speciesData);
+if (TRACE_RESOLVE) {
+// Used by jlink species pregeneration plugin, see
+// jdk.tools.jlink.internal.plugins.GenerateJLIClassesPlugin
+System.out.println("[SPECIES_RESOLVE] " + className + " (generated)");
+}
+// This operation causes a lot of churn:
+linkSpeciesDataToCode(speciesData, speciesCode);
+// This operation commits the relation, but causes little churn:
+linkCodeToSpeciesData(speciesCode, speciesData, false);
+} catch (Error ex) {
+if (TRACE_RESOLVE) {
+System.out.println("[SPECIES_RESOLVE] " + className + " (Error #2)" );
+}
+// We can get here if there is a race condition loading a class.
+// Or maybe we are out of resources.  Back out of the CHM.get and retry.
+throw ex;
+}
+}
+if (!speciesData.isResolved()) {
+throw newInternalError("bad species class linkage for " + className + ": " + speciesData);
+}
+assert(speciesData == factory.loadSpeciesDataFromCode(speciesCode));
+return speciesData;
+}
+/**
+* Generate a concrete subclass of the top class for a given combination of bound types.
+*
+* A concrete species subclass roughly matches the following schema:
+*
+* <pre>
+* class Species_[[types]] extends [[T]] {
+*     final [[S]] speciesData() { return ... }
+*     static [[T]] make([[fields]]) { return ... }
+*     [[fields]]
+*     final [[T]] transform([[args]]) { return ... }
+* }
+* </pre>
+*
+* The {@code [[types]]} signature is precisely the key for the species.
+*
+* The {@code [[fields]]} section consists of one field definition per character in
+* the type signature, adhering to the naming schema described in the definition of
+* {@link #chooseFieldName}.
+*
+* For example, a concrete species for two references and one integral bound value
+* has a shape like the following:
+*
+* <pre>
+* class TopClass { ... private static
+* final class Species_LLI extends TopClass {
+*     final Object argL0;
+*     final Object argL1;
+*     final int argI2;
+*     private Species_LLI(CT ctarg, ..., Object argL0, Object argL1, int argI2) {
+*         super(ctarg, ...);
+*         this.argL0 = argL0;
+*         this.argL1 = argL1;
+*         this.argI2 = argI2;
+*     }
+*     final SpeciesData speciesData() { return BMH_SPECIES; }
+*     &#64;Stable static SpeciesData BMH_SPECIES; // injected afterwards
+*     static TopClass make(CT ctarg, ..., Object argL0, Object argL1, int argI2) {
+*         return new Species_LLI(ctarg, ..., argL0, argL1, argI2);
+*     }
+*     final TopClass copyWith(CT ctarg, ...) {
+*         return new Species_LLI(ctarg, ..., argL0, argL1, argI2);
+*     }
+*     // two transforms, for the sake of illustration:
+*     final TopClass copyWithExtendL(CT ctarg, ..., Object narg) {
+*         return BMH_SPECIES.transform(L_TYPE).invokeBasic(ctarg, ..., argL0, argL1, argI2, narg);
+*     }
+*     final TopClass copyWithExtendI(CT ctarg, ..., int narg) {
+*         return BMH_SPECIES.transform(I_TYPE).invokeBasic(ctarg, ..., argL0, argL1, argI2, narg);
+*     }
+* }
+* </pre>
+*
+* @param className of the species
+* @param speciesData what species we are generating
+* @return the generated concrete TopClass class
+*/
+Class<? extends T> generateConcreteSpeciesCode(String className, ClassSpecializer<T,K,S>.SpeciesData speciesData) {
+byte[] classFile = generateConcreteSpeciesCodeFile(className, speciesData);
+// load class
+InvokerBytecodeGenerator.maybeDump(classBCName(className), classFile);
+Class<?> speciesCode;
+ClassLoader cl = topClass().getClassLoader();
+ProtectionDomain pd = null;
+if (cl != null) {
+pd = AccessController.doPrivileged(
+new PrivilegedAction<>() {
+@Override
+public ProtectionDomain run() {
+return topClass().getProtectionDomain();
+}
+});
+}
+try {
+speciesCode = UNSAFE.defineClass(className, classFile, 0, classFile.length, cl, pd);
+} catch (Exception ex) {
+throw newInternalError(ex);
+}
+return speciesCode.asSubclass(topClass());
+}
+// These are named like constants because there is only one per specialization scheme:
+private final String SPECIES_DATA = classBCName(metaType);
+private final String SPECIES_DATA_SIG = classSig(SPECIES_DATA);
+private final String SPECIES_DATA_NAME = sdAccessor.getName();
+private final int SPECIES_DATA_MODS = sdAccessor.getModifiers();
+private final List<String> TRANSFORM_NAMES;  // derived from transformMethods
+private final List<MethodType> TRANSFORM_TYPES;
+private final List<Integer> TRANSFORM_MODS;
+{
+// Tear apart transformMethods to get the names, types, and modifiers.
+List<String> tns = new ArrayList<>();
+List<MethodType> tts = new ArrayList<>();
+List<Integer> tms = new ArrayList<>();
+for (int i = 0; i < transformMethods.size(); i++) {
+MemberName tm = transformMethods.get(i);
+tns.add(tm.getName());
+final MethodType tt = tm.getMethodType();
+tts.add(tt);
+tms.add(tm.getModifiers());
+}
+TRANSFORM_NAMES = List.of(tns.toArray(new String[0]));
+TRANSFORM_TYPES = List.of(tts.toArray(new MethodType[0]));
+TRANSFORM_MODS = List.of(tms.toArray(new Integer[0]));
+}
+private static final int ACC_PPP = ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED;
+/*non-public*/ byte[] generateConcreteSpeciesCodeFile(String className0, ClassSpecializer<T,K,S>.SpeciesData speciesData) {
+final String className = classBCName(className0);
+final String superClassName = classBCName(speciesData.deriveSuperClass());
+final ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
+final int NOT_ACC_PUBLIC = 0;  // not ACC_PUBLIC
+cw.visit(V1_6, NOT_ACC_PUBLIC + ACC_FINAL + ACC_SUPER, className, null, superClassName, null);
+final String sourceFile = className.substring(className.lastIndexOf('.')+1);
+cw.visitSource(sourceFile, null);
+// emit static types and BMH_SPECIES fields
+FieldVisitor fw = cw.visitField(NOT_ACC_PUBLIC + ACC_STATIC, sdFieldName, SPECIES_DATA_SIG, null, null);
+fw.visitAnnotation(STABLE_SIG, true);
+fw.visitEnd();
+// handy holder for dealing with groups of typed values (ctor arguments and fields)
+class Var {
+final int index;
+final String name;
+final Class<?> type;
+final String desc;
+final BasicType basicType;
+final int slotIndex;
+Var(int index, int slotIndex) {
+this.index = index;
+this.slotIndex = slotIndex;
+name = null; type = null; desc = null;
+basicType = BasicType.V_TYPE;
+}
+Var(String name, Class<?> type, Var prev) {
+int slotIndex = prev.nextSlotIndex();
+int index = prev.nextIndex();
+if (name == null)  name = "x";
+if (name.endsWith("#"))
+name = name.substring(0, name.length()-1) + index;
+assert(!type.equals(void.class));
+String desc = classSig(type);
+BasicType basicType = BasicType.basicType(type);
+this.index = index;
+this.name = name;
+this.type = type;
+this.desc = desc;
+this.basicType = basicType;
+this.slotIndex = slotIndex;
+}
+Var lastOf(List<Var> vars) {
+int n = vars.size();
+return (n == 0 ? this : vars.get(n-1));
+}
+<X> List<Var> fromTypes(List<X> types) {
+Var prev = this;
+ArrayList<Var> result = new ArrayList<>(types.size());
+int i = 0;
+for (X x : types) {
+String vn = name;
+Class<?> vt;
+if (x instanceof Class) {
+vt = (Class<?>) x;
+// make the names friendlier if debugging
+assert((vn = vn + "_" + (i++)) != null);
+} else {
+@SuppressWarnings("unchecked")
+Var v = (Var) x;
+vn = v.name;
+vt = v.type;
+}
+prev = new Var(vn, vt, prev);
+result.add(prev);
+}
+return result;
+}
+int slotSize() { return basicType.basicTypeSlots(); }
+int nextIndex() { return index + (slotSize() == 0 ? 0 : 1); }
+int nextSlotIndex() { return slotIndex >= 0 ? slotIndex + slotSize() : slotIndex; }
+boolean isInHeap() { return slotIndex < 0; }
+void emitVarInstruction(int asmop, MethodVisitor mv) {
+if (asmop == ALOAD)
+asmop = typeLoadOp(basicType.basicTypeChar());
+else
+throw new AssertionError("bad op="+asmop+" for desc="+desc);
+mv.visitVarInsn(asmop, slotIndex);
+}
+public void emitFieldInsn(int asmop, MethodVisitor mv) {
+mv.visitFieldInsn(asmop, className, name, desc);
+}
+}
+final Var NO_THIS = new Var(0, 0),
+AFTER_THIS = new Var(0, 1),
+IN_HEAP = new Var(0, -1);
+// figure out the field types
+final List<Class<?>> fieldTypes = speciesData.fieldTypes();
+final List<Var> fields = new ArrayList<>(fieldTypes.size());
+{
+Var nextF = IN_HEAP;
+for (Class<?> ft : fieldTypes) {
+String fn = chooseFieldName(ft, nextF.nextIndex());
+nextF = new Var(fn, ft, nextF);
+fields.add(nextF);
+}
+}
+// emit bound argument fields
+for (Var field : fields) {
+cw.visitField(ACC_FINAL, field.name, field.desc, null, null).visitEnd();
+}
+MethodVisitor mv;
+// emit implementation of speciesData()
+mv = cw.visitMethod((SPECIES_DATA_MODS & ACC_PPP) + ACC_FINAL,
+SPECIES_DATA_NAME, "()" + SPECIES_DATA_SIG, null, null);
+mv.visitCode();
+mv.visitFieldInsn(GETSTATIC, className, sdFieldName, SPECIES_DATA_SIG);
+mv.visitInsn(ARETURN);
+mv.visitMaxs(0, 0);
+mv.visitEnd();
+// figure out the constructor arguments
+MethodType superCtorType = ClassSpecializer.this.baseConstructorType();
+MethodType thisCtorType = superCtorType.appendParameterTypes(fieldTypes);
+// emit constructor
+{
+mv = cw.visitMethod(ACC_PRIVATE,
+"<init>", methodSig(thisCtorType), null, null);
+mv.visitCode();
+mv.visitVarInsn(ALOAD, 0); // this
+final List<Var> ctorArgs = AFTER_THIS.fromTypes(superCtorType.parameterList());
+for (Var ca : ctorArgs) {
+ca.emitVarInstruction(ALOAD, mv);
+}
+// super(ca...)
+mv.visitMethodInsn(INVOKESPECIAL, superClassName,
+"<init>", methodSig(superCtorType), false);
+// store down fields
+Var lastFV = AFTER_THIS.lastOf(ctorArgs);
+for (Var f : fields) {
+// this.argL1 = argL1
+mv.visitVarInsn(ALOAD, 0);  // this
+lastFV = new Var(f.name, f.type, lastFV);
+lastFV.emitVarInstruction(ALOAD, mv);
+f.emitFieldInsn(PUTFIELD, mv);
+}
+mv.visitInsn(RETURN);
+mv.visitMaxs(0, 0);
+mv.visitEnd();
+}
+// emit make()  ...factory method wrapping constructor
+{
+MethodType ftryType = thisCtorType.changeReturnType(topClass());
+mv = cw.visitMethod(NOT_ACC_PUBLIC + ACC_STATIC,
+"make", methodSig(ftryType), null, null);
+mv.visitCode();
+// make instance
+mv.visitTypeInsn(NEW, className);
+mv.visitInsn(DUP);
+// load factory method arguments:  ctarg... and arg...
+for (Var v : NO_THIS.fromTypes(ftryType.parameterList())) {
+v.emitVarInstruction(ALOAD, mv);
+}
+// finally, invoke the constructor and return
+mv.visitMethodInsn(INVOKESPECIAL, className,
+"<init>", methodSig(thisCtorType), false);
+mv.visitInsn(ARETURN);
+mv.visitMaxs(0, 0);
+mv.visitEnd();
+}
+// For each transform, emit the customized override of the transform method.
+// This method mixes together some incoming arguments (from the transform's
+// static type signature) with the field types themselves, and passes
+// the resulting mish-mosh of values to a method handle produced by
+// the species itself.  (Typically this method handle is the factory
+// method of this species or a related one.)
+for (int whichtm = 0; whichtm < TRANSFORM_NAMES.size(); whichtm++) {
+final String     TNAME = TRANSFORM_NAMES.get(whichtm);
+final MethodType TTYPE = TRANSFORM_TYPES.get(whichtm);
+final int        TMODS = TRANSFORM_MODS.get(whichtm);
+mv = cw.visitMethod((TMODS & ACC_PPP) | ACC_FINAL,
+TNAME, TTYPE.toMethodDescriptorString(), null, E_THROWABLE);
+mv.visitCode();
+// return a call to the corresponding "transform helper", something like this:
+//   MY_SPECIES.transformHelper(whichtm).invokeBasic(ctarg, ..., argL0, ..., xarg)
+mv.visitFieldInsn(GETSTATIC, className,
+sdFieldName, SPECIES_DATA_SIG);
+emitIntConstant(whichtm, mv);
+mv.visitMethodInsn(INVOKEVIRTUAL, SPECIES_DATA,
+"transformHelper", "(I)" + MH_SIG, false);
+List<Var> targs = AFTER_THIS.fromTypes(TTYPE.parameterList());
+List<Var> tfields = new ArrayList<>(fields);
+// mix them up and load them for the transform helper:
+List<Var> helperArgs = speciesData.deriveTransformHelperArguments(transformMethods.get(whichtm), whichtm, targs, tfields);
+List<Class<?>> helperTypes = new ArrayList<>(helperArgs.size());
+for (Var ha : helperArgs) {
+helperTypes.add(ha.basicType.basicTypeClass());
+if (ha.isInHeap()) {
+assert(tfields.contains(ha));
+mv.visitVarInsn(ALOAD, 0);
+ha.emitFieldInsn(GETFIELD, mv);
+} else {
+assert(targs.contains(ha));
+ha.emitVarInstruction(ALOAD, mv);
+}
+}
+// jump into the helper (which is probably a factory method)
+final Class<?> rtype = TTYPE.returnType();
+final BasicType rbt = BasicType.basicType(rtype);
+MethodType invokeBasicType = MethodType.methodType(rbt.basicTypeClass(), helperTypes);
+mv.visitMethodInsn(INVOKEVIRTUAL, MH,
+"invokeBasic", methodSig(invokeBasicType), false);
+if (rbt == BasicType.L_TYPE) {
+mv.visitTypeInsn(CHECKCAST, classBCName(rtype));
+mv.visitInsn(ARETURN);
+} else {
+throw newInternalError("NYI: transform of type "+rtype);
+}
+mv.visitMaxs(0, 0);
+mv.visitEnd();
+}
+cw.visitEnd();
+return cw.toByteArray();
+}
+private int typeLoadOp(char t) {
+switch (t) {
+case 'L': return ALOAD;
+case 'I': return ILOAD;
+case 'J': return LLOAD;
+case 'F': return FLOAD;
+case 'D': return DLOAD;
+default : throw newInternalError("unrecognized type " + t);
+}
+}
+private void emitIntConstant(int con, MethodVisitor mv) {
+if (ICONST_M1 - ICONST_0 <= con && con <= ICONST_5 - ICONST_0)
+mv.visitInsn(ICONST_0 + con);
+else if (con == (byte) con)
+mv.visitIntInsn(BIPUSH, con);
+else if (con == (short) con)
+mv.visitIntInsn(SIPUSH, con);
+else {
+mv.visitLdcInsn(con);
+}
+}
+//
+// Getter MH generation.
+//
+private MethodHandle findGetter(Class<?> speciesCode, List<Class<?>> types, int index) {
+Class<?> fieldType = types.get(index);
+String fieldName = chooseFieldName(fieldType, index);
+try {
+return IMPL_LOOKUP.findGetter(speciesCode, fieldName, fieldType);
+} catch (NoSuchFieldException | IllegalAccessException e) {
+throw newInternalError(e);
+}
+}
+private List<MethodHandle> findGetters(Class<?> speciesCode, List<Class<?>> types) {
+MethodHandle[] mhs = new MethodHandle[types.size()];
+for (int i = 0; i < mhs.length; ++i) {
+mhs[i] = findGetter(speciesCode, types, i);
+assert(mhs[i].internalMemberName().getDeclaringClass() == speciesCode);
+}
+return List.of(mhs);
+}
+private List<MethodHandle> findFactories(Class<? extends T> speciesCode, List<Class<?>> types) {
+MethodHandle[] mhs = new MethodHandle[1];
+mhs[0] = findFactory(speciesCode, types);
+return List.of(mhs);
+}
+List<LambdaForm.NamedFunction> makeNominalGetters(List<Class<?>> types, List<MethodHandle> getters) {
+LambdaForm.NamedFunction[] nfs = new LambdaForm.NamedFunction[types.size()];
+for (int i = 0; i < nfs.length; ++i) {
+nfs[i] = new LambdaForm.NamedFunction(getters.get(i));
+}
+return List.of(nfs);
+}
+//
+// Auxiliary methods.
+//
+protected void linkSpeciesDataToCode(ClassSpecializer<T,K,S>.SpeciesData speciesData, Class<? extends T> speciesCode) {
+speciesData.speciesCode = speciesCode.asSubclass(topClass);
+final List<Class<?>> types = speciesData.fieldTypes;
+speciesData.factories = this.findFactories(speciesCode, types);
+speciesData.getters = this.findGetters(speciesCode, types);
+speciesData.nominalGetters = this.makeNominalGetters(types, speciesData.getters);
+}
+private Field reflectSDField(Class<? extends T> speciesCode) {
+final Field field = reflectField(speciesCode, sdFieldName);
+assert(field.getType() == metaType);
+assert(Modifier.isStatic(field.getModifiers()));
+return field;
+}
+private S readSpeciesDataFromCode(Class<? extends T> speciesCode) {
+try {
+MemberName sdField = IMPL_LOOKUP.resolveOrFail(REF_getStatic, speciesCode, sdFieldName, metaType);
+Object base = MethodHandleNatives.staticFieldBase(sdField);
+long offset = MethodHandleNatives.staticFieldOffset(sdField);
+UNSAFE.loadFence();
+return metaType.cast(UNSAFE.getObject(base, offset));
+} catch (Error err) {
+throw err;
+} catch (Exception ex) {
+throw newInternalError("Failed to load speciesData from speciesCode: " + speciesCode.getName(), ex);
+} catch (Throwable t) {
+throw uncaughtException(t);
+}
+}
+protected S loadSpeciesDataFromCode(Class<? extends T> speciesCode) {
+if (speciesCode == topClass()) {
+return topSpecies;
+}
+S result = readSpeciesDataFromCode(speciesCode);
+if (result.outer() != ClassSpecializer.this) {
+throw newInternalError("wrong class");
+}
+return result;
+}
+protected void linkCodeToSpeciesData(Class<? extends T> speciesCode, ClassSpecializer<T,K,S>.SpeciesData speciesData, boolean salvage) {
+try {
+assert(readSpeciesDataFromCode(speciesCode) == null ||
+(salvage && readSpeciesDataFromCode(speciesCode).equals(speciesData)));
+MemberName sdField = IMPL_LOOKUP.resolveOrFail(REF_putStatic, speciesCode, sdFieldName, metaType);
+Object base = MethodHandleNatives.staticFieldBase(sdField);
+long offset = MethodHandleNatives.staticFieldOffset(sdField);
+UNSAFE.storeFence();
+UNSAFE.putObject(base, offset, speciesData);
+UNSAFE.storeFence();
+} catch (Error err) {
+throw err;
+} catch (Exception ex) {
+throw newInternalError("Failed to link speciesData to speciesCode: " + speciesCode.getName(), ex);
+} catch (Throwable t) {
+throw uncaughtException(t);
+}
+}
+/**
+* Field names in concrete species classes adhere to this pattern:
+* type + index, where type is a single character (L, I, J, F, D).
+* The factory subclass can customize this.
+* The name is purely cosmetic, since it applies to a private field.
+*/
+protected String chooseFieldName(Class<?> type, int index) {
+BasicType bt = BasicType.basicType(type);
+return "" + bt.basicTypeChar() + index;
+}
+MethodHandle findFactory(Class<? extends T> speciesCode, List<Class<?>> types) {
+final MethodType type = baseConstructorType().changeReturnType(topClass()).appendParameterTypes(types);
+try {
+return IMPL_LOOKUP.findStatic(speciesCode, "make", type);
+} catch (NoSuchMethodException | IllegalAccessException | IllegalArgumentException | TypeNotPresentException e) {
+throw newInternalError(e);
+}
+}
+}
+/** Hook that virtualizes the Factory class, allowing subclasses to extend it. */
+protected Factory makeFactory() {
+return new Factory();
+}
+// Other misc helpers:
+private static final String MH = "java/lang/invoke/MethodHandle";
+private static final String MH_SIG = "L" + MH + ";";
+private static final String STABLE = "jdk/internal/vm/annotation/Stable";
+private static final String STABLE_SIG = "L" + STABLE + ";";
+private static final String[] E_THROWABLE = new String[] { "java/lang/Throwable" };
+static {
+assert(MH_SIG.equals(classSig(MethodHandle.class)));
+assert(MH.equals(classBCName(MethodHandle.class)));
+}
+static String methodSig(MethodType mt) {
+return mt.toMethodDescriptorString();
+}
+static String classSig(Class<?> cls) {
+if (cls.isPrimitive() || cls.isArray())
+return MethodType.methodType(cls).toMethodDescriptorString().substring(2);
+return classSig(classBCName(cls));
+}
+static String classSig(String bcName) {
+assert(bcName.indexOf('.') < 0);
+assert(!bcName.endsWith(";"));
+assert(!bcName.startsWith("["));
+return "L" + bcName + ";";
+}
+static String classBCName(Class<?> cls) {
+return classBCName(className(cls));
+}
+static String classBCName(String str) {
+assert(str.indexOf('/') < 0) : str;
+return str.replace('.', '/');
+}
+static String className(Class<?> cls) {
+assert(!cls.isArray() && !cls.isPrimitive());
+return cls.getName();
+}
+}

changeset 47753	a2008587c13f
child 49885	b2e74972c7d4