1 /*
   2  * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package jdk.experimental.value;
  27 
  28 import java.lang.invoke.MethodHandle;
  29 import java.lang.invoke.MethodHandles;
  30 import java.lang.invoke.MethodHandles.Lookup;
  31 import java.lang.invoke.MethodType;
  32 import java.lang.reflect.Field;
  33 import java.lang.reflect.Method;
  34 import java.lang.reflect.Modifier;
  35 import java.util.Arrays;
  36 import java.util.List;
  37 import java.util.Map;
  38 import java.util.Objects;
  39 import java.util.Optional;
  40 import java.util.concurrent.ConcurrentHashMap;
  41 import java.util.stream.Stream;
  42 
  43 import jdk.experimental.value.ValueType.ValueHandleKind.ValueHandleKey;
  44 import jdk.experimental.bytecode.MacroCodeBuilder.CondKind;
  45 import jdk.experimental.bytecode.TypeTag;
  46 import jdk.internal.misc.Unsafe;
  47 import sun.invoke.util.BytecodeDescriptor;
  48 import sun.invoke.util.Wrapper;
  49 import valhalla.shady.MinimalValueTypes_1_0;
  50 
  51 // Rough place holder just now...
  52 public class ValueType<T> {
  53 
  54     static final Unsafe UNSAFE = Unsafe.getUnsafe();
  55 
  56     enum ValueHandleKind {
  57         BOX,
  58         UNBOX,
  59         DEFAULT,
  60         EQ,
  61         HASH,
  62         WITHER() {
  63             @Override
  64             ValueHandleKey key(Object fieldName) {
  65                return new ValueHandleKey(this, fieldName);
  66             }
  67         },
  68         NEWARRAY,
  69         VALOAD,
  70         VASTORE,
  71         MULTINEWARRAY() {
  72             @Override
  73             ValueHandleKey key(Object dims) {
  74                return new ValueHandleKey(this, dims);
  75             }
  76         },
  77         IDENTITY,
  78         GETTER() {
  79             @Override
  80             ValueHandleKey key(Object fieldName) {
  81                return new ValueHandleKey(this, fieldName);
  82             }
  83         };
  84 
  85         ValueHandleKey key() {
  86             return new ValueHandleKey(this, null);
  87         }
  88 
  89         ValueHandleKey key(Object optArg) {
  90             throw new IllegalStateException();
  91         }
  92 
  93         static class ValueHandleKey {
  94             ValueHandleKind kind;
  95             Optional<Object> optArg;
  96 
  97             ValueHandleKey(ValueHandleKind kind, Object optArg) {
  98                 this.kind = kind;
  99                 this.optArg = Optional.ofNullable(optArg);
 100             }
 101 
 102             @Override
 103             public boolean equals(Object obj) {
 104                 if (obj instanceof ValueHandleKey) {
 105                     ValueHandleKey that = (ValueHandleKey)obj;
 106                     return Objects.equals(kind, that.kind) &&
 107                             Objects.equals(optArg, that.optArg);
 108                 } else {
 109                     return false;
 110                 }
 111             }
 112 
 113             @Override
 114             public int hashCode() {
 115                 return Objects.hashCode(kind) * 31 + Objects.hashCode(optArg);
 116             }
 117         }
 118     }
 119 
 120     private static final Lookup IMPL_LOOKUP;
 121 
 122     static {
 123         try {
 124             Field f = Lookup.class.getDeclaredField("IMPL_LOOKUP");
 125             f.setAccessible(true);
 126             IMPL_LOOKUP = (Lookup)f.get(null);
 127         } catch (ReflectiveOperationException ex) {
 128             throw new AssertionError(ex);
 129         }
 130     }
 131 
 132     private static final ConcurrentHashMap<Class<?>, ValueType<?>> BOX_TO_VT = new ConcurrentHashMap<>();
 133 
 134     public static boolean classHasValueType(Class<?> x) {
 135         return MinimalValueTypes_1_0.classHasValueType(x);
 136     }
 137 
 138     @SuppressWarnings("unchecked")
 139     public static <T> ValueType<T> forClass(Class<T> x) {
 140         ValueType<T> vt = (ValueType<T>) BOX_TO_VT.get(x);
 141         if (vt != null) {
 142             return vt;
 143         }
 144 
 145         try {
 146             Class<T> valueClass = (Class<T>) MinimalValueTypes_1_0.getValueTypeClass(x);
 147             vt = new ValueType<T>(x, valueClass);
 148             ValueType<T> old = (ValueType<T>) BOX_TO_VT.putIfAbsent(x, vt);
 149             if (old != null) {
 150                 vt = old;
 151             }
 152             return vt;
 153         }
 154         catch (ClassNotFoundException cne) {
 155             throw new IllegalArgumentException("Class " + x + " not bound to ValueType", cne);
 156         }
 157     }
 158 
 159     private Lookup boxLookup;
 160     private Lookup valueLookup;
 161     private Map<ValueHandleKind.ValueHandleKey, MethodHandle> handleMap = new ConcurrentHashMap<>();
 162 
 163     private ValueType(Class<T> boxClass, Class<T> valueClass) {
 164         this.boxLookup = IMPL_LOOKUP.in(boxClass);
 165         this.valueLookup = IMPL_LOOKUP.in(valueClass);
 166     }
 167 
 168     @SuppressWarnings("unchecked")
 169     public Class<T> boxClass() {
 170         return (Class<T>)boxLookup.lookupClass();
 171     }
 172 
 173     public Class<?> sourceClass() {
 174         return boxClass();
 175     }
 176 
 177     public Class<?> valueClass() {
 178         return valueLookup.lookupClass();
 179     }
 180 
 181     public Class<?> arrayValueClass() {
 182         return arrayValueClass(1);
 183     }
 184 
 185     public Class<?> arrayValueClass(int dims) {
 186         try {
 187             String dimsStr = "[[[[[[[[[[[[[[[[";
 188             if (dims < 1 || dims > 16) {
 189                 throw new IllegalArgumentException("cannot create array class for dimension > 16");
 190             }
 191             return Class.forName(dimsStr.substring(0, dims) + "Q" + valueClass().getName() + ";", false, boxLookup.lookupClass().getClassLoader());
 192         } catch (ClassNotFoundException ex) {
 193             throw new IllegalStateException(ex);
 194         }
 195     }
 196 
 197     public String toString() {
 198         return "ValueType boxClass=" + boxClass() + " valueClass=" + valueClass();
 199     }
 200 
 201     String mhName(String opName) {
 202         return sourceClass().getName() + "_" + opName;
 203     }
 204 
 205     public MethodHandle defaultValueConstant() {
 206         ValueHandleKey key = ValueHandleKind.DEFAULT.key();
 207         MethodHandle result = handleMap.get(key);
 208         if (result == null) {
 209             result = MethodHandleBuilder.loadCode(boxLookup, mhName("default"), MethodType.methodType(valueClass()),
 210                     C -> {
 211                         C.vdefault(valueClass()).vreturn();
 212                     });
 213             handleMap.put(key, result);
 214         }
 215         return result;
 216     }
 217 
 218     public MethodHandle substitutabilityTest() {
 219         ValueHandleKey key = ValueHandleKind.EQ.key();
 220         MethodHandle result = handleMap.get(key);
 221         if (result == null) {
 222             result = MethodHandleBuilder.loadCode(valueLookup, mhName("subTest"), MethodType.methodType(boolean.class, valueClass(), valueClass()),
 223                     C -> {
 224                         for (Field f : valueFields()) {
 225                             String fDesc = BytecodeDescriptor.unparse(f.getType());
 226                             C.vload(0).vgetfield(valueClass(), f.getName(), fDesc);
 227                             C.vload(1).vgetfield(valueClass(), f.getName(), fDesc);
 228                             if (f.getType().isPrimitive()) {
 229                                 C.ifcmp(fDesc, CondKind.NE, "fail");
 230                             } else {
 231                                 C.invokestatic(Objects.class, "equals", "(Ljava/lang/Object;Ljava/lang/Object;)Z", false);
 232                                 C.const_(0).ifcmp(TypeTag.I, CondKind.EQ, "fail");
 233                             }
 234                         }
 235                         C.const_(1);
 236                         C.ireturn();
 237                         C.label("fail");
 238                         C.const_(0);
 239                         C.ireturn();
 240                     });
 241             handleMap.put(key, result);
 242         }
 243         return result;
 244     }
 245 
 246     public MethodHandle substitutabilityHashCode() {
 247         ValueHandleKey key = ValueHandleKind.HASH.key();
 248         MethodHandle result = handleMap.get(key);
 249         if (result == null) {
 250             result = MethodHandleBuilder.loadCode(valueLookup, mhName("subHash"), MethodType.methodType(int.class, valueClass()),
 251                     C -> {
 252                         C.withLocal("res", "I");
 253                         C.const_(1).store("res");
 254                         for (Field f : valueFields()) {
 255                             String desc = BytecodeDescriptor.unparse(f.getType());
 256                             C.vload(0).vgetfield(valueClass(), f.getName(), desc);
 257                             if (f.getType().isPrimitive()) {
 258                                 C.invokestatic(Wrapper.asWrapperType(f.getType()), "hashCode", "(" + desc + ")I", false);
 259                             } else {
 260                                 C.invokestatic(Objects.class, "hashCode", "(Ljava/lang/Object;)I", false);
 261                             }
 262                             C.load("res").const_(31).imul();
 263                             C.iadd().store("res");
 264                         }
 265                         C.load("res").ireturn();
 266                     });
 267             handleMap.put(key, result);
 268         }
 269         return result;
 270     }
 271 
 272     public MethodHandle findWither(Lookup lookup, String name, Class<?> type) throws NoSuchFieldException, IllegalAccessException {
 273         ValueHandleKey key = ValueHandleKind.WITHER.key(List.of(name, type));
 274         MethodHandle result = handleMap.get(key);
 275         if (result == null) {
 276             String fieldType = BytecodeDescriptor.unparse(type);
 277 
 278             result = MethodHandleBuilder.loadCode(valueLookup, mhName("wither$" + name), MethodType.methodType(valueClass(), valueClass(), type),
 279                     C -> C.vload(0).load(1).vwithfield(valueClass(), name, fieldType).vreturn());
 280             handleMap.put(key, result);
 281         }
 282 
 283         // Allow access if the lookup class is the VCC or DVT and the lookup
 284         // has private access
 285         Class<?> lc = lookup.lookupClass();
 286         if (lookup.hasPrivateAccess() && (valueClass() == lc || boxClass() == lc)) {
 287             return result;
 288         }
 289         throw new IllegalAccessException(String.format("Class %s does not have vwithfield access to field %s.%s",
 290                                                        lc.getName(), boxClass().getName(), name));
 291     }
 292 
 293     public MethodHandle unbox() {
 294         ValueHandleKey key = ValueHandleKind.UNBOX.key();
 295         MethodHandle result = handleMap.get(key);
 296         if (result == null) {
 297             result = MethodHandleBuilder.loadCode(boxLookup, mhName("unbox"), MethodType.methodType(valueClass(), boxClass()),
 298                     C -> {
 299                         C.load(0).vunbox(valueClass()).vreturn();
 300                     });
 301             handleMap.put(key, result);
 302         }
 303         return result;
 304     }
 305 
 306     public MethodHandle box() {
 307         ValueHandleKey key = ValueHandleKind.BOX.key();
 308         MethodHandle result = handleMap.get(key);
 309         if (result == null) {
 310             result = MethodHandleBuilder.loadCode(boxLookup, mhName("box"), MethodType.methodType(boxClass(), valueClass()),
 311                     C -> {
 312                         C.vload(0).vbox(boxClass()).areturn();
 313                     });
 314             handleMap.put(key, result);
 315         }
 316         return result;
 317     }
 318 
 319     public MethodHandle newArray() {
 320         Class<?> arrayValueClass = arrayValueClass();
 321         ValueHandleKey key = ValueHandleKind.NEWARRAY.key();
 322         MethodHandle result = handleMap.get(key);
 323         if (result == null) {
 324             result = MethodHandleBuilder.loadCode(boxLookup, mhName("newArray"), MethodType.methodType(arrayValueClass, int.class),
 325                     C -> {
 326                         C.load(0).anewarray(valueClass()).areturn();
 327                     });
 328             handleMap.put(key, result);
 329         }
 330         return result;
 331     }
 332 
 333     public MethodHandle arrayGetter() {
 334         Class<?> arrayValueClass = arrayValueClass();
 335         ValueHandleKey key = ValueHandleKind.VALOAD.key();
 336         MethodHandle result = handleMap.get(key);
 337         if (result == null) {
 338             result = MethodHandleBuilder.loadCode(boxLookup, mhName("arrayGet"), MethodType.methodType(valueClass(), arrayValueClass, int.class),
 339                     C -> {
 340                         C.load(0).load(1).vaload().vreturn();
 341                     });
 342             handleMap.put(key, result);
 343         }
 344         return result;
 345     }
 346 
 347     public MethodHandle arraySetter() {
 348         Class<?> arrayValueClass = arrayValueClass();
 349         ValueHandleKey key = ValueHandleKind.VASTORE.key();
 350         MethodHandle result = handleMap.get(key);
 351         if (result == null) {
 352             result = MethodHandleBuilder.loadCode(boxLookup, mhName("arraySet"), MethodType.methodType(void.class, arrayValueClass, int.class, valueClass()),
 353                     C -> {
 354                         C.load(0).load(1).load(2).vastore().return_();
 355                     });
 356             handleMap.put(key, result);
 357         }
 358         return result;
 359     }
 360 
 361     public MethodHandle newMultiArray(int dims) {
 362         Class<?> arrayValueClass = arrayValueClass(dims);
 363         ValueHandleKey key = ValueHandleKind.MULTINEWARRAY.key(dims);
 364         MethodHandle result = handleMap.get(key);
 365         Class<?>[] params = new Class<?>[dims];
 366         Arrays.fill(params, int.class);
 367         if (result == null) {
 368             result = MethodHandleBuilder.loadCode(boxLookup, mhName("newMultiArray"), MethodType.methodType(arrayValueClass, params),
 369                     C -> {
 370                         for (int i = 0 ; i < dims ; i++) {
 371                             C.load(i);
 372                         }
 373                         C.multianewarray(arrayValueClass, (byte)dims).areturn();
 374                     });
 375             handleMap.put(key, result);
 376         }
 377         return result;
 378     }
 379 
 380     public MethodHandle identity() {
 381         ValueHandleKey key = ValueHandleKind.IDENTITY.key();
 382         MethodHandle result = handleMap.get(key);
 383         if (result == null) {
 384             result = MethodHandleBuilder.loadCode(boxLookup, mhName("identity"), MethodType.methodType(valueClass(), valueClass()),
 385                     C -> C.vload(0).vreturn());
 386             handleMap.put(key, result);
 387         }
 388         return result;
 389     }
 390 
 391     public MethodHandle findGetter(Lookup lookup, String name, Class<?> type) throws NoSuchFieldException, IllegalAccessException {
 392         ValueHandleKey key = ValueHandleKind.GETTER.key(List.of(name, type));
 393         MethodHandle result = handleMap.get(key);
 394         if (result == null) {
 395             String fieldType = BytecodeDescriptor.unparse(type);
 396             result = MethodHandleBuilder.loadCode(boxLookup, mhName("getter$" + name), MethodType.methodType(type, valueClass()),
 397                     C -> C.vload(0).vgetfield(valueClass(), name, fieldType).return_(fieldType));
 398             handleMap.put(key, result);
 399         }
 400         //force access-check
 401         lookup.findGetter(boxClass(), name, type);
 402         return result;
 403     }
 404 
 405     private Field[] valueFields() {
 406         int valFieldMask = Modifier.FINAL;
 407         return Stream.of(sourceClass().getDeclaredFields())
 408                 .filter(f -> (f.getModifiers() & (valFieldMask | Modifier.STATIC)) == valFieldMask)
 409                 .toArray(Field[]::new);
 410     }
 411 
 412 }