1 /*
   2  * Copyright (c) 2008, 2013, 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 java.lang.invoke;
  27 
  28 import static jdk.internal.org.objectweb.asm.Opcodes.*;
  29 import static java.lang.invoke.LambdaForm.basicTypes;
  30 import static java.lang.invoke.MethodHandleNatives.Constants.REF_invokeStatic;
  31 import static java.lang.invoke.MethodHandleStatics.*;
  32 
  33 import java.lang.invoke.LambdaForm.Name;
  34 import java.lang.invoke.LambdaForm.NamedFunction;
  35 import java.lang.invoke.MethodHandles.Lookup;
  36 import java.lang.reflect.Field;
  37 import java.util.Arrays;
  38 import java.util.HashMap;
  39 
  40 import sun.invoke.util.ValueConversions;
  41 import sun.invoke.util.Wrapper;
  42 
  43 import jdk.internal.org.objectweb.asm.ClassWriter;
  44 import jdk.internal.org.objectweb.asm.MethodVisitor;
  45 import jdk.internal.org.objectweb.asm.Type;
  46 
  47 /**
  48  * The flavor of method handle which emulates an invoke instruction
  49  * on a predetermined argument.  The JVM dispatches to the correct method
  50  * when the handle is created, not when it is invoked.
  51  *
  52  * All bound arguments are encapsulated in dedicated species.
  53  */
  54 /* non-public */ abstract class BoundMethodHandle extends MethodHandle {
  55 
  56     /* non-public */ BoundMethodHandle(MethodType type, LambdaForm form) {
  57         super(type, form);
  58     }
  59 
  60     //
  61     // BMH API and internals
  62     //
  63 
  64     static MethodHandle bindSingle(MethodType type, LambdaForm form, char xtype, Object x) {
  65         // for some type signatures, there exist pre-defined concrete BMH classes
  66         try {
  67             switch (xtype) {
  68             case 'L':
  69                 if (true)  return bindSingle(type, form, x);  // Use known fast path.
  70                 return (BoundMethodHandle) SpeciesData.EMPTY.extendWithType('L').constructor[0].invokeBasic(type, form, x);
  71             case 'I':
  72                 return (BoundMethodHandle) SpeciesData.EMPTY.extendWithType('I').constructor[0].invokeBasic(type, form, ValueConversions.widenSubword(x));
  73             case 'J':
  74                 return (BoundMethodHandle) SpeciesData.EMPTY.extendWithType('J').constructor[0].invokeBasic(type, form, (long) x);
  75             case 'F':
  76                 return (BoundMethodHandle) SpeciesData.EMPTY.extendWithType('F').constructor[0].invokeBasic(type, form, (float) x);
  77             case 'D':
  78                 return (BoundMethodHandle) SpeciesData.EMPTY.extendWithType('D').constructor[0].invokeBasic(type, form, (double) x);
  79             default : throw new InternalError("unexpected xtype: " + xtype);
  80             }
  81         } catch (Throwable t) {
  82             throw newInternalError(t);
  83         }
  84     }
  85 
  86     static MethodHandle bindSingle(MethodType type, LambdaForm form, Object x) {
  87             return new Species_L(type, form, x);
  88     }
  89 
  90     MethodHandle cloneExtend(MethodType type, LambdaForm form, char xtype, Object x) {
  91         try {
  92             switch (xtype) {
  93             case 'L': return cloneExtendL(type, form, x);
  94             case 'I': return cloneExtendI(type, form, ValueConversions.widenSubword(x));
  95             case 'J': return cloneExtendJ(type, form, (long) x);
  96             case 'F': return cloneExtendF(type, form, (float) x);
  97             case 'D': return cloneExtendD(type, form, (double) x);
  98             }
  99         } catch (Throwable t) {
 100             throw newInternalError(t);
 101         }
 102         throw new InternalError("unexpected type: " + xtype);
 103     }
 104 
 105     @Override
 106     MethodHandle bindArgument(int pos, char basicType, Object value) {
 107         MethodType type = type().dropParameterTypes(pos, pos+1);
 108         LambdaForm form = internalForm().bind(1+pos, speciesData());
 109         return cloneExtend(type, form, basicType, value);
 110     }
 111 
 112     @Override
 113     MethodHandle dropArguments(MethodType srcType, int pos, int drops) {
 114         LambdaForm form = internalForm().addArguments(pos, srcType.parameterList().subList(pos, pos+drops));
 115         try {
 116              return clone(srcType, form);
 117          } catch (Throwable t) {
 118              throw newInternalError(t);
 119          }
 120     }
 121 
 122     @Override
 123     MethodHandle permuteArguments(MethodType newType, int[] reorder) {
 124         try {
 125              return clone(newType, form.permuteArguments(1, reorder, basicTypes(newType.parameterList())));
 126          } catch (Throwable t) {
 127              throw newInternalError(t);
 128          }
 129     }
 130 
 131     static final String EXTENSION_TYPES = "LIJFD";
 132     static final byte INDEX_L = 0, INDEX_I = 1, INDEX_J = 2, INDEX_F = 3, INDEX_D = 4;
 133     static byte extensionIndex(char type) {
 134         int i = EXTENSION_TYPES.indexOf(type);
 135         if (i < 0)  throw new InternalError();
 136         return (byte) i;
 137     }
 138 
 139     /**
 140      * Return the {@link SpeciesData} instance representing this BMH species. All subclasses must provide a
 141      * static field containing this value, and they must accordingly implement this method.
 142      */
 143     protected abstract SpeciesData speciesData();
 144 
 145     @Override
 146     final Object internalProperties() {
 147         return "/BMH="+internalValues();
 148     }
 149 
 150     @Override
 151     final Object internalValues() {
 152         Object[] boundValues = new Object[speciesData().fieldCount()];
 153         for (int i = 0; i < boundValues.length; ++i) {
 154             boundValues[i] = arg(i);
 155         }
 156         return Arrays.asList(boundValues);
 157     }
 158 
 159     public final Object arg(int i) {
 160         try {
 161             switch (speciesData().fieldType(i)) {
 162             case 'L': return argL(i);
 163             case 'I': return argI(i);
 164             case 'F': return argF(i);
 165             case 'D': return argD(i);
 166             case 'J': return argJ(i);
 167             }
 168         } catch (Throwable ex) {
 169             throw newInternalError(ex);
 170         }
 171         throw new InternalError("unexpected type: " + speciesData().types+"."+i);
 172     }
 173     public final Object argL(int i) throws Throwable { return          speciesData().getters[i].invokeBasic(this); }
 174     public final int    argI(int i) throws Throwable { return (int)    speciesData().getters[i].invokeBasic(this); }
 175     public final float  argF(int i) throws Throwable { return (float)  speciesData().getters[i].invokeBasic(this); }
 176     public final double argD(int i) throws Throwable { return (double) speciesData().getters[i].invokeBasic(this); }
 177     public final long   argJ(int i) throws Throwable { return (long)   speciesData().getters[i].invokeBasic(this); }
 178 
 179     //
 180     // cloning API
 181     //
 182 
 183     public abstract BoundMethodHandle clone(MethodType mt, LambdaForm lf) throws Throwable;
 184     public abstract BoundMethodHandle cloneExtendL(MethodType mt, LambdaForm lf, Object narg) throws Throwable;
 185     public abstract BoundMethodHandle cloneExtendI(MethodType mt, LambdaForm lf, int    narg) throws Throwable;
 186     public abstract BoundMethodHandle cloneExtendJ(MethodType mt, LambdaForm lf, long   narg) throws Throwable;
 187     public abstract BoundMethodHandle cloneExtendF(MethodType mt, LambdaForm lf, float  narg) throws Throwable;
 188     public abstract BoundMethodHandle cloneExtendD(MethodType mt, LambdaForm lf, double narg) throws Throwable;
 189 
 190     // The following is a grossly irregular hack:
 191     @Override MethodHandle reinvokerTarget() {
 192         try {
 193             return (MethodHandle) argL(0);
 194         } catch (Throwable ex) {
 195             throw newInternalError(ex);
 196         }
 197     }
 198 
 199     //
 200     // concrete BMH classes required to close bootstrap loops
 201     //
 202 
 203     private  // make it private to force users to access the enclosing class first
 204     static final class Species_L extends BoundMethodHandle {
 205         final Object argL0;
 206         public Species_L(MethodType mt, LambdaForm lf, Object argL0) {
 207             super(mt, lf);
 208             this.argL0 = argL0;
 209         }
 210         // The following is a grossly irregular hack:
 211         @Override MethodHandle reinvokerTarget() { return (MethodHandle) argL0; }
 212         @Override
 213         public SpeciesData speciesData() {
 214             return SPECIES_DATA;
 215         }
 216         public static final SpeciesData SPECIES_DATA = SpeciesData.getForClass("L", Species_L.class);
 217         @Override
 218         public final BoundMethodHandle clone(MethodType mt, LambdaForm lf) throws Throwable {
 219             return new Species_L(mt, lf, argL0);
 220         }
 221         @Override
 222         public final BoundMethodHandle cloneExtendL(MethodType mt, LambdaForm lf, Object narg) throws Throwable {
 223             return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_L).constructor[0].invokeBasic(mt, lf, argL0, narg);
 224         }
 225         @Override
 226         public final BoundMethodHandle cloneExtendI(MethodType mt, LambdaForm lf, int narg) throws Throwable {
 227             return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_I).constructor[0].invokeBasic(mt, lf, argL0, narg);
 228         }
 229         @Override
 230         public final BoundMethodHandle cloneExtendJ(MethodType mt, LambdaForm lf, long narg) throws Throwable {
 231             return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_J).constructor[0].invokeBasic(mt, lf, argL0, narg);
 232         }
 233         @Override
 234         public final BoundMethodHandle cloneExtendF(MethodType mt, LambdaForm lf, float narg) throws Throwable {
 235             return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_F).constructor[0].invokeBasic(mt, lf, argL0, narg);
 236         }
 237         @Override
 238         public final BoundMethodHandle cloneExtendD(MethodType mt, LambdaForm lf, double narg) throws Throwable {
 239             return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_D).constructor[0].invokeBasic(mt, lf, argL0, narg);
 240         }
 241     }
 242 
 243 /*
 244     static final class Species_LL extends BoundMethodHandle {
 245         final Object argL0;
 246         final Object argL1;
 247         public Species_LL(MethodType mt, LambdaForm lf, Object argL0, Object argL1) {
 248             super(mt, lf);
 249             this.argL0 = argL0;
 250             this.argL1 = argL1;
 251         }
 252         @Override
 253         public SpeciesData speciesData() {
 254             return SPECIES_DATA;
 255         }
 256         public static final SpeciesData SPECIES_DATA = SpeciesData.getForClass("LL", Species_LL.class);
 257         @Override
 258         public final BoundMethodHandle clone(MethodType mt, LambdaForm lf) throws Throwable {
 259             return new Species_LL(mt, lf, argL0, argL1);
 260         }
 261         @Override
 262         public final BoundMethodHandle cloneExtendL(MethodType mt, LambdaForm lf, Object narg) throws Throwable {
 263             return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_L).constructor[0].invokeBasic(mt, lf, argL0, argL1, narg);
 264         }
 265         @Override
 266         public final BoundMethodHandle cloneExtendI(MethodType mt, LambdaForm lf, int narg) throws Throwable {
 267             return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_I).constructor[0].invokeBasic(mt, lf, argL0, argL1, narg);
 268         }
 269         @Override
 270         public final BoundMethodHandle cloneExtendJ(MethodType mt, LambdaForm lf, long narg) throws Throwable {
 271             return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_J).constructor[0].invokeBasic(mt, lf, argL0, argL1, narg);
 272         }
 273         @Override
 274         public final BoundMethodHandle cloneExtendF(MethodType mt, LambdaForm lf, float narg) throws Throwable {
 275             return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_F).constructor[0].invokeBasic(mt, lf, argL0, argL1, narg);
 276         }
 277         @Override
 278         public final BoundMethodHandle cloneExtendD(MethodType mt, LambdaForm lf, double narg) throws Throwable {
 279             return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_D).constructor[0].invokeBasic(mt, lf, argL0, argL1, narg);
 280         }
 281     }
 282 
 283     static final class Species_JL extends BoundMethodHandle {
 284         final long argJ0;
 285         final Object argL1;
 286         public Species_JL(MethodType mt, LambdaForm lf, long argJ0, Object argL1) {
 287             super(mt, lf);
 288             this.argJ0 = argJ0;
 289             this.argL1 = argL1;
 290         }
 291         @Override
 292         public SpeciesData speciesData() {
 293             return SPECIES_DATA;
 294         }
 295         public static final SpeciesData SPECIES_DATA = SpeciesData.getForClass("JL", Species_JL.class);
 296         @Override public final long   argJ0() { return argJ0; }
 297         @Override public final Object argL1() { return argL1; }
 298         @Override
 299         public final BoundMethodHandle clone(MethodType mt, LambdaForm lf) throws Throwable {
 300             return new Species_JL(mt, lf, argJ0, argL1);
 301         }
 302         @Override
 303         public final BoundMethodHandle cloneExtendL(MethodType mt, LambdaForm lf, Object narg) throws Throwable {
 304             return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_L).constructor[0].invokeBasic(mt, lf, argJ0, argL1, narg);
 305         }
 306         @Override
 307         public final BoundMethodHandle cloneExtendI(MethodType mt, LambdaForm lf, int narg) throws Throwable {
 308             return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_I).constructor[0].invokeBasic(mt, lf, argJ0, argL1, narg);
 309         }
 310         @Override
 311         public final BoundMethodHandle cloneExtendJ(MethodType mt, LambdaForm lf, long narg) throws Throwable {
 312             return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_J).constructor[0].invokeBasic(mt, lf, argJ0, argL1, narg);
 313         }
 314         @Override
 315         public final BoundMethodHandle cloneExtendF(MethodType mt, LambdaForm lf, float narg) throws Throwable {
 316             return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_F).constructor[0].invokeBasic(mt, lf, argJ0, argL1, narg);
 317         }
 318         @Override
 319         public final BoundMethodHandle cloneExtendD(MethodType mt, LambdaForm lf, double narg) throws Throwable {
 320             return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_D).constructor[0].invokeBasic(mt, lf, argJ0, argL1, narg);
 321         }
 322     }
 323 */
 324 
 325     //
 326     // BMH species meta-data
 327     //
 328 
 329     /**
 330      * Meta-data wrapper for concrete BMH classes.
 331      */
 332     static class SpeciesData {
 333         final String                             types;
 334         final Class<? extends BoundMethodHandle> clazz;
 335         // Bootstrapping requires circular relations MH -> BMH -> SpeciesData -> MH
 336         // Therefore, we need a non-final link in the chain.  Use array elements.
 337         final MethodHandle[]                     constructor;
 338         final MethodHandle[]                     getters;
 339         final SpeciesData[]                      extensions;
 340 
 341         public int fieldCount() {
 342             return types.length();
 343         }
 344         public char fieldType(int i) {
 345             return types.charAt(i);
 346         }
 347 
 348         public String toString() {
 349             return "SpeciesData["+(isPlaceholder() ? "<placeholder>" : clazz.getSimpleName())+":"+types+"]";
 350         }
 351 
 352         /**
 353          * Return a {@link LambdaForm.Name} containing a {@link LambdaForm.NamedFunction} that
 354          * represents a MH bound to a generic invoker, which in turn forwards to the corresponding
 355          * getter.
 356          */
 357         Name getterName(Name mhName, int i) {
 358             MethodHandle mh = getters[i];
 359             assert(mh != null) : this+"."+i;
 360             return new Name(mh, mhName);
 361         }
 362 
 363         NamedFunction getterFunction(int i) {
 364             return new NamedFunction(getters[i]);
 365         }
 366 
 367         static final SpeciesData EMPTY = new SpeciesData("", BoundMethodHandle.class);
 368 
 369         private SpeciesData(String types, Class<? extends BoundMethodHandle> clazz) {
 370             this.types = types;
 371             this.clazz = clazz;
 372             if (!INIT_DONE) {
 373                 this.constructor = new MethodHandle[1];
 374                 this.getters = new MethodHandle[types.length()];
 375             } else {
 376                 this.constructor = Factory.makeCtors(clazz, types, null);
 377                 this.getters = Factory.makeGetters(clazz, types, null);
 378             }
 379             this.extensions = new SpeciesData[EXTENSION_TYPES.length()];
 380         }
 381 
 382         private void initForBootstrap() {
 383             assert(!INIT_DONE);
 384             if (constructor[0] == null) {
 385                 Factory.makeCtors(clazz, types, this.constructor);
 386                 Factory.makeGetters(clazz, types, this.getters);
 387             }
 388         }
 389 
 390         private SpeciesData(String types) {
 391             // Placeholder only.
 392             this.types = types;
 393             this.clazz = null;
 394             this.constructor = null;
 395             this.getters = null;
 396             this.extensions = null;
 397         }
 398         private boolean isPlaceholder() { return clazz == null; }
 399 
 400         private static final HashMap<String, SpeciesData> CACHE = new HashMap<>();
 401         static { CACHE.put("", EMPTY); }  // make bootstrap predictable
 402         private static final boolean INIT_DONE;  // set after <clinit> finishes...
 403 
 404         SpeciesData extendWithType(char type) {
 405             int i = extensionIndex(type);
 406             SpeciesData d = extensions[i];
 407             if (d != null)  return d;
 408             extensions[i] = d = get(types+type);
 409             return d;
 410         }
 411 
 412         SpeciesData extendWithIndex(byte index) {
 413             SpeciesData d = extensions[index];
 414             if (d != null)  return d;
 415             extensions[index] = d = get(types+EXTENSION_TYPES.charAt(index));
 416             return d;
 417         }
 418 
 419         private static SpeciesData get(String types) {
 420             // Acquire cache lock for query.
 421             SpeciesData d = lookupCache(types);
 422             if (!d.isPlaceholder())
 423                 return d;
 424             synchronized (d) {
 425                 // Use synch. on the placeholder to prevent multiple instantiation of one species.
 426                 // Creating this class forces a recursive call to getForClass.
 427                 if (lookupCache(types).isPlaceholder())
 428                     Factory.generateConcreteBMHClass(types);
 429             }
 430             // Reacquire cache lock.
 431             d = lookupCache(types);
 432             // Class loading must have upgraded the cache.
 433             assert(d != null && !d.isPlaceholder());
 434             return d;
 435         }
 436         static SpeciesData getForClass(String types, Class<? extends BoundMethodHandle> clazz) {
 437             // clazz is a new class which is initializing its SPECIES_DATA field
 438             return updateCache(types, new SpeciesData(types, clazz));
 439         }
 440         private static synchronized SpeciesData lookupCache(String types) {
 441             SpeciesData d = CACHE.get(types);
 442             if (d != null)  return d;
 443             d = new SpeciesData(types);
 444             assert(d.isPlaceholder());
 445             CACHE.put(types, d);
 446             return d;
 447         }
 448         private static synchronized SpeciesData updateCache(String types, SpeciesData d) {
 449             SpeciesData d2;
 450             assert((d2 = CACHE.get(types)) == null || d2.isPlaceholder());
 451             assert(!d.isPlaceholder());
 452             CACHE.put(types, d);
 453             return d;
 454         }
 455 
 456         static {
 457             // pre-fill the BMH speciesdata cache with BMH's inner classes
 458             final Class<BoundMethodHandle> rootCls = BoundMethodHandle.class;
 459             SpeciesData d0 = BoundMethodHandle.SPECIES_DATA;  // trigger class init
 460             assert(d0 == null || d0 == lookupCache("")) : d0;
 461             try {
 462                 for (Class<?> c : rootCls.getDeclaredClasses()) {
 463                     if (rootCls.isAssignableFrom(c)) {
 464                         final Class<? extends BoundMethodHandle> cbmh = c.asSubclass(BoundMethodHandle.class);
 465                         SpeciesData d = Factory.speciesDataFromConcreteBMHClass(cbmh);
 466                         assert(d != null) : cbmh.getName();
 467                         assert(d.clazz == cbmh);
 468                         assert(d == lookupCache(d.types));
 469                     }
 470                 }
 471             } catch (Throwable e) {
 472                 throw newInternalError(e);
 473             }
 474 
 475             for (SpeciesData d : CACHE.values()) {
 476                 d.initForBootstrap();
 477             }
 478             // Note:  Do not simplify this, because INIT_DONE must not be
 479             // a compile-time constant during bootstrapping.
 480             INIT_DONE = Boolean.TRUE;
 481         }
 482     }
 483 
 484     static SpeciesData getSpeciesData(String types) {
 485         return SpeciesData.get(types);
 486     }
 487 
 488     /**
 489      * Generation of concrete BMH classes.
 490      *
 491      * A concrete BMH species is fit for binding a number of values adhering to a
 492      * given type pattern. Reference types are erased.
 493      *
 494      * BMH species are cached by type pattern.
 495      *
 496      * A BMH species has a number of fields with the concrete (possibly erased) types of
 497      * bound values. Setters are provided as an API in BMH. Getters are exposed as MHs,
 498      * which can be included as names in lambda forms.
 499      */
 500     static class Factory {
 501 
 502         static final String JLO_SIG  = "Ljava/lang/Object;";
 503         static final String JLS_SIG  = "Ljava/lang/String;";
 504         static final String JLC_SIG  = "Ljava/lang/Class;";
 505         static final String MH       = "java/lang/invoke/MethodHandle";
 506         static final String MH_SIG   = "L"+MH+";";
 507         static final String BMH      = "java/lang/invoke/BoundMethodHandle";
 508         static final String BMH_SIG  = "L"+BMH+";";
 509         static final String SPECIES_DATA     = "java/lang/invoke/BoundMethodHandle$SpeciesData";
 510         static final String SPECIES_DATA_SIG = "L"+SPECIES_DATA+";";
 511 
 512         static final String SPECIES_PREFIX_NAME = "Species_";
 513         static final String SPECIES_PREFIX_PATH = BMH + "$" + SPECIES_PREFIX_NAME;
 514 
 515         static final String BMHSPECIES_DATA_EWI_SIG = "(B)" + SPECIES_DATA_SIG;
 516         static final String BMHSPECIES_DATA_GFC_SIG = "(" + JLS_SIG + JLC_SIG + ")" + SPECIES_DATA_SIG;
 517         static final String MYSPECIES_DATA_SIG = "()" + SPECIES_DATA_SIG;
 518         static final String VOID_SIG   = "()V";
 519 
 520         static final String SIG_INCIPIT = "(Ljava/lang/invoke/MethodType;Ljava/lang/invoke/LambdaForm;";
 521 
 522         static final Class<?>[] TYPES = new Class<?>[] { Object.class, int.class, long.class, float.class, double.class };
 523 
 524         static final String[] E_THROWABLE = new String[] { "java/lang/Throwable" };
 525 
 526         /**
 527          * Generate a concrete subclass of BMH for a given combination of bound types.
 528          *
 529          * A concrete BMH species adheres to the following schema:
 530          *
 531          * <pre>
 532          * class Species_[[types]] extends BoundMethodHandle {
 533          *     [[fields]]
 534          *     final SpeciesData speciesData() { return SpeciesData.get("[[types]]"); }
 535          * }
 536          * </pre>
 537          *
 538          * The {@code [[types]]} signature is precisely the string that is passed to this
 539          * method.
 540          *
 541          * The {@code [[fields]]} section consists of one field definition per character in
 542          * the type signature, adhering to the naming schema described in the definition of
 543          * {@link #makeFieldName}.
 544          *
 545          * For example, a concrete BMH species for two reference and one integral bound values
 546          * would have the following shape:
 547          *
 548          * <pre>
 549          * class BoundMethodHandle { ... private static
 550          * final class Species_LLI extends BoundMethodHandle {
 551          *     final Object argL0;
 552          *     final Object argL1;
 553          *     final int argI2;
 554          *     public Species_LLI(MethodType mt, LambdaForm lf, Object argL0, Object argL1, int argI2) {
 555          *         super(mt, lf);
 556          *         this.argL0 = argL0;
 557          *         this.argL1 = argL1;
 558          *         this.argI2 = argI2;
 559          *     }
 560          *     public final SpeciesData speciesData() { return SPECIES_DATA; }
 561          *     public static final SpeciesData SPECIES_DATA = SpeciesData.getForClass("LLI", Species_LLI.class);
 562          *     public final BoundMethodHandle clone(MethodType mt, LambdaForm lf) {
 563          *         return SPECIES_DATA.constructor[0].invokeBasic(mt, lf, argL0, argL1, argI2);
 564          *     }
 565          *     public final BoundMethodHandle cloneExtendL(MethodType mt, LambdaForm lf, Object narg) {
 566          *         return SPECIES_DATA.extendWithIndex(INDEX_L).constructor[0].invokeBasic(mt, lf, argL0, argL1, argI2, narg);
 567          *     }
 568          *     public final BoundMethodHandle cloneExtendI(MethodType mt, LambdaForm lf, int narg) {
 569          *         return SPECIES_DATA.extendWithIndex(INDEX_I).constructor[0].invokeBasic(mt, lf, argL0, argL1, argI2, narg);
 570          *     }
 571          *     public final BoundMethodHandle cloneExtendJ(MethodType mt, LambdaForm lf, long narg) {
 572          *         return SPECIES_DATA.extendWithIndex(INDEX_J).constructor[0].invokeBasic(mt, lf, argL0, argL1, argI2, narg);
 573          *     }
 574          *     public final BoundMethodHandle cloneExtendF(MethodType mt, LambdaForm lf, float narg) {
 575          *         return SPECIES_DATA.extendWithIndex(INDEX_F).constructor[0].invokeBasic(mt, lf, argL0, argL1, argI2, narg);
 576          *     }
 577          *     public final BoundMethodHandle cloneExtendD(MethodType mt, LambdaForm lf, double narg) {
 578          *         return SPECIES_DATA.extendWithIndex(INDEX_D).constructor[0].invokeBasic(mt, lf, argL0, argL1, argI2, narg);
 579          *     }
 580          * }
 581          * </pre>
 582          *
 583          * @param types the type signature, wherein reference types are erased to 'L'
 584          * @return the generated concrete BMH class
 585          */
 586         static Class<? extends BoundMethodHandle> generateConcreteBMHClass(String types) {
 587             final ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
 588 
 589             final String className  = SPECIES_PREFIX_PATH + types;
 590             final String sourceFile = SPECIES_PREFIX_NAME + types;
 591             cw.visit(V1_6, ACC_PUBLIC + ACC_FINAL + ACC_SUPER, className, null, BMH, null);
 592             cw.visitSource(sourceFile, null);
 593 
 594             // emit static types and SPECIES_DATA fields
 595             cw.visitField(ACC_PUBLIC + ACC_STATIC, "SPECIES_DATA", SPECIES_DATA_SIG, null, null).visitEnd();
 596 
 597             // emit bound argument fields
 598             for (int i = 0; i < types.length(); ++i) {
 599                 final char t = types.charAt(i);
 600                 final String fieldName = makeFieldName(types, i);
 601                 final String fieldDesc = t == 'L' ? JLO_SIG : String.valueOf(t);
 602                 cw.visitField(ACC_FINAL, fieldName, fieldDesc, null, null).visitEnd();
 603             }
 604 
 605             MethodVisitor mv;
 606 
 607             // emit constructor
 608             mv = cw.visitMethod(ACC_PUBLIC, "<init>", makeSignature(types, true), null, null);
 609             mv.visitCode();
 610             mv.visitVarInsn(ALOAD, 0);
 611             mv.visitVarInsn(ALOAD, 1);
 612             mv.visitVarInsn(ALOAD, 2);
 613 
 614             mv.visitMethodInsn(INVOKESPECIAL, BMH, "<init>", makeSignature("", true));
 615 
 616             for (int i = 0, j = 0; i < types.length(); ++i, ++j) {
 617                 // i counts the arguments, j counts corresponding argument slots
 618                 char t = types.charAt(i);
 619                 mv.visitVarInsn(ALOAD, 0);
 620                 mv.visitVarInsn(typeLoadOp(t), j + 3); // parameters start at 3
 621                 mv.visitFieldInsn(PUTFIELD, className, makeFieldName(types, i), typeSig(t));
 622                 if (t == 'J' || t == 'D') {
 623                     ++j; // adjust argument register access
 624                 }
 625             }
 626 
 627             mv.visitInsn(RETURN);
 628             mv.visitMaxs(0, 0);
 629             mv.visitEnd();
 630 
 631             // emit implementation of reinvokerTarget()
 632             mv = cw.visitMethod(ACC_PUBLIC + ACC_FINAL, "reinvokerTarget", "()" + MH_SIG, null, null);
 633             mv.visitCode();
 634             mv.visitVarInsn(ALOAD, 0);
 635             mv.visitFieldInsn(GETFIELD, className, "argL0", JLO_SIG);
 636             mv.visitTypeInsn(CHECKCAST, MH);
 637             mv.visitInsn(ARETURN);
 638             mv.visitMaxs(0, 0);
 639             mv.visitEnd();
 640 
 641             // emit implementation of speciesData()
 642             mv = cw.visitMethod(ACC_PUBLIC + ACC_FINAL, "speciesData", MYSPECIES_DATA_SIG, null, null);
 643             mv.visitCode();
 644             mv.visitFieldInsn(GETSTATIC, className, "SPECIES_DATA", SPECIES_DATA_SIG);
 645             mv.visitInsn(ARETURN);
 646             mv.visitMaxs(0, 0);
 647             mv.visitEnd();
 648 
 649             // emit clone()
 650             mv = cw.visitMethod(ACC_PUBLIC + ACC_FINAL, "clone", makeSignature("", false), null, E_THROWABLE);
 651             mv.visitCode();
 652             // return speciesData().constructor[0].invokeBasic(mt, lf, argL0, ...)
 653             // obtain constructor
 654             mv.visitVarInsn(ALOAD, 0);
 655             mv.visitFieldInsn(GETSTATIC, className, "SPECIES_DATA", SPECIES_DATA_SIG);
 656             mv.visitFieldInsn(GETFIELD, SPECIES_DATA, "constructor", "[" + MH_SIG);
 657             mv.visitInsn(ICONST_0);
 658             mv.visitInsn(AALOAD);
 659             // load mt, lf
 660             mv.visitVarInsn(ALOAD, 1);
 661             mv.visitVarInsn(ALOAD, 2);
 662             // put fields on the stack
 663             emitPushFields(types, className, mv);
 664             // finally, invoke the constructor and return
 665             mv.visitMethodInsn(INVOKEVIRTUAL, MH, "invokeBasic", makeSignature(types, false));
 666             mv.visitInsn(ARETURN);
 667             mv.visitMaxs(0, 0);
 668             mv.visitEnd();
 669 
 670             // for each type, emit cloneExtendT()
 671             for (Class<?> c : TYPES) {
 672                 char t = Wrapper.basicTypeChar(c);
 673                 mv = cw.visitMethod(ACC_PUBLIC + ACC_FINAL, "cloneExtend" + t, makeSignature(String.valueOf(t), false), null, E_THROWABLE);
 674                 mv.visitCode();
 675                 // return SPECIES_DATA.extendWithIndex(extensionIndex(t)).constructor[0].invokeBasic(mt, lf, argL0, ..., narg)
 676                 // obtain constructor
 677                 mv.visitFieldInsn(GETSTATIC, className, "SPECIES_DATA", SPECIES_DATA_SIG);
 678                 int iconstInsn = ICONST_0 + extensionIndex(t);
 679                 assert(iconstInsn <= ICONST_5);
 680                 mv.visitInsn(iconstInsn);
 681                 mv.visitMethodInsn(INVOKEVIRTUAL, SPECIES_DATA, "extendWithIndex", BMHSPECIES_DATA_EWI_SIG);
 682                 mv.visitFieldInsn(GETFIELD, SPECIES_DATA, "constructor", "[" + MH_SIG);
 683                 mv.visitInsn(ICONST_0);
 684                 mv.visitInsn(AALOAD);
 685                 // load mt, lf
 686                 mv.visitVarInsn(ALOAD, 1);
 687                 mv.visitVarInsn(ALOAD, 2);
 688                 // put fields on the stack
 689                 emitPushFields(types, className, mv);
 690                 // put narg on stack
 691                 mv.visitVarInsn(typeLoadOp(t), 3);
 692                 // finally, invoke the constructor and return
 693                 mv.visitMethodInsn(INVOKEVIRTUAL, MH, "invokeBasic", makeSignature(types + t, false));
 694                 mv.visitInsn(ARETURN);
 695                 mv.visitMaxs(0, 0);
 696                 mv.visitEnd();
 697             }
 698 
 699             // emit class initializer
 700             mv = cw.visitMethod(ACC_PUBLIC | ACC_STATIC, "<clinit>", VOID_SIG, null, null);
 701             mv.visitCode();
 702             mv.visitLdcInsn(types);
 703             mv.visitLdcInsn(Type.getObjectType(className));
 704             mv.visitMethodInsn(INVOKESTATIC, SPECIES_DATA, "getForClass", BMHSPECIES_DATA_GFC_SIG);
 705             mv.visitFieldInsn(PUTSTATIC, className, "SPECIES_DATA", SPECIES_DATA_SIG);
 706             mv.visitInsn(RETURN);
 707             mv.visitMaxs(0, 0);
 708             mv.visitEnd();
 709 
 710             cw.visitEnd();
 711 
 712             // load class
 713             final byte[] classFile = cw.toByteArray();
 714             InvokerBytecodeGenerator.maybeDump(className, classFile);
 715             Class<? extends BoundMethodHandle> bmhClass =
 716                 //UNSAFE.defineAnonymousClass(BoundMethodHandle.class, classFile, null).asSubclass(BoundMethodHandle.class);
 717                 UNSAFE.defineClass(className, classFile, 0, classFile.length,
 718                                    BoundMethodHandle.class.getClassLoader(), null)
 719                     .asSubclass(BoundMethodHandle.class);
 720             UNSAFE.ensureClassInitialized(bmhClass);
 721 
 722             return bmhClass;
 723         }
 724 
 725         private static int typeLoadOp(char t) {
 726             switch (t) {
 727             case 'L': return ALOAD;
 728             case 'I': return ILOAD;
 729             case 'J': return LLOAD;
 730             case 'F': return FLOAD;
 731             case 'D': return DLOAD;
 732             default : throw new InternalError("unrecognized type " + t);
 733             }
 734         }
 735 
 736         private static void emitPushFields(String types, String className, MethodVisitor mv) {
 737             for (int i = 0; i < types.length(); ++i) {
 738                 char tc = types.charAt(i);
 739                 mv.visitVarInsn(ALOAD, 0);
 740                 mv.visitFieldInsn(GETFIELD, className, makeFieldName(types, i), typeSig(tc));
 741             }
 742         }
 743 
 744         static String typeSig(char t) {
 745             return t == 'L' ? JLO_SIG : String.valueOf(t);
 746         }
 747 
 748         //
 749         // Getter MH generation.
 750         //
 751 
 752         private static MethodHandle makeGetter(Class<?> cbmhClass, String types, int index) {
 753             String fieldName = makeFieldName(types, index);
 754             Class<?> fieldType = Wrapper.forBasicType(types.charAt(index)).primitiveType();
 755             try {
 756                 return LOOKUP.findGetter(cbmhClass, fieldName, fieldType);
 757             } catch (NoSuchFieldException | IllegalAccessException e) {
 758                 throw newInternalError(e);
 759             }
 760         }
 761 
 762         static MethodHandle[] makeGetters(Class<?> cbmhClass, String types, MethodHandle[] mhs) {
 763             if (mhs == null)  mhs = new MethodHandle[types.length()];
 764             for (int i = 0; i < mhs.length; ++i) {
 765                 mhs[i] = makeGetter(cbmhClass, types, i);
 766                 assert(mhs[i].internalMemberName().getDeclaringClass() == cbmhClass);
 767             }
 768             return mhs;
 769         }
 770 
 771         static MethodHandle[] makeCtors(Class<? extends BoundMethodHandle> cbmh, String types, MethodHandle mhs[]) {
 772             if (mhs == null)  mhs = new MethodHandle[1];
 773             mhs[0] = makeCbmhCtor(cbmh, types);
 774             return mhs;
 775         }
 776 
 777         //
 778         // Auxiliary methods.
 779         //
 780 
 781         static SpeciesData speciesDataFromConcreteBMHClass(Class<? extends BoundMethodHandle> cbmh) {
 782             try {
 783                 Field F_SPECIES_DATA = cbmh.getDeclaredField("SPECIES_DATA");
 784                 return (SpeciesData) F_SPECIES_DATA.get(null);
 785             } catch (ReflectiveOperationException ex) {
 786                 throw newInternalError(ex);
 787             }
 788         }
 789 
 790         /**
 791          * Field names in concrete BMHs adhere to this pattern:
 792          * arg + type + index
 793          * where type is a single character (L, I, J, F, D).
 794          */
 795         private static String makeFieldName(String types, int index) {
 796             assert index >= 0 && index < types.length();
 797             return "arg" + types.charAt(index) + index;
 798         }
 799 
 800         private static String makeSignature(String types, boolean ctor) {
 801             StringBuilder buf = new StringBuilder(SIG_INCIPIT);
 802             for (char c : types.toCharArray()) {
 803                 buf.append(typeSig(c));
 804             }
 805             return buf.append(')').append(ctor ? "V" : BMH_SIG).toString();
 806         }
 807 
 808         static MethodHandle makeCbmhCtor(Class<? extends BoundMethodHandle> cbmh, String types) {
 809             try {
 810                 return linkConstructor(LOOKUP.findConstructor(cbmh, MethodType.fromMethodDescriptorString(makeSignature(types, true), null)));
 811             } catch (NoSuchMethodException | IllegalAccessException | IllegalArgumentException | TypeNotPresentException e) {
 812                 throw newInternalError(e);
 813             }
 814         }
 815 
 816         /**
 817          * Wrap a constructor call in a {@link LambdaForm}.
 818          *
 819          * If constructors ({@code <init>} methods) are called in LFs, problems might arise if the LFs
 820          * are turned into bytecode, because the call to the allocator is routed through an MH, and the
 821          * verifier cannot find a {@code NEW} instruction preceding the {@code INVOKESPECIAL} to
 822          * {@code <init>}. To avoid this, we add an indirection by invoking {@code <init>} through
 823          * {@link MethodHandle#linkToSpecial}.
 824          *
 825          * The last {@link LambdaForm.Name Name} in the argument's form is expected to be the {@code void}
 826          * result of the {@code <init>} invocation. This entry is replaced.
 827          */
 828         private static MethodHandle linkConstructor(MethodHandle cmh) {
 829             final LambdaForm lf = cmh.form;
 830             final int initNameIndex = lf.names.length - 1;
 831             final Name initName = lf.names[initNameIndex];
 832             final MemberName ctorMN = initName.function.member;
 833             final MethodType ctorMT = ctorMN.getInvocationType();
 834 
 835             // obtain function member (call target)
 836             // linker method type replaces initial parameter (BMH species) with BMH to avoid naming a species (anonymous class!)
 837             final MethodType linkerMT = ctorMT.changeParameterType(0, BoundMethodHandle.class).appendParameterTypes(MemberName.class);
 838             MemberName linkerMN = new MemberName(MethodHandle.class, "linkToSpecial", linkerMT, REF_invokeStatic);
 839             try {
 840                 linkerMN = MemberName.getFactory().resolveOrFail(REF_invokeStatic, linkerMN, null, NoSuchMethodException.class);
 841                 assert(linkerMN.isStatic());
 842             } catch (ReflectiveOperationException ex) {
 843                 throw newInternalError(ex);
 844             }
 845             // extend arguments array
 846             Object[] newArgs = Arrays.copyOf(initName.arguments, initName.arguments.length + 1);
 847             newArgs[newArgs.length - 1] = ctorMN;
 848             // replace function
 849             final NamedFunction nf = new NamedFunction(linkerMN);
 850             final Name linkedCtor = new Name(nf, newArgs);
 851             linkedCtor.initIndex(initNameIndex);
 852             lf.names[initNameIndex] = linkedCtor;
 853             return cmh;
 854         }
 855 
 856     }
 857 
 858     private static final Lookup LOOKUP = Lookup.IMPL_LOOKUP;
 859 
 860     /**
 861      * All subclasses must provide such a value describing their type signature.
 862      */
 863     static final SpeciesData SPECIES_DATA = SpeciesData.EMPTY;
 864 
 865     private static final SpeciesData[] SPECIES_DATA_CACHE = new SpeciesData[5];
 866     private static SpeciesData checkCache(int size, String types) {
 867         int idx = size - 1;
 868         SpeciesData data = SPECIES_DATA_CACHE[idx];
 869         if (data != null)  return data;
 870         SPECIES_DATA_CACHE[idx] = data = getSpeciesData(types);
 871         return data;
 872     }
 873     static SpeciesData speciesData_L()     { return checkCache(1, "L"); }
 874     static SpeciesData speciesData_LL()    { return checkCache(2, "LL"); }
 875     static SpeciesData speciesData_LLL()   { return checkCache(3, "LLL"); }
 876     static SpeciesData speciesData_LLLL()  { return checkCache(4, "LLLL"); }
 877     static SpeciesData speciesData_LLLLL() { return checkCache(5, "LLLLL"); }
 878 }