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src/java.base/share/classes/java/lang/invoke/BoundMethodHandle.java

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  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.*;
  30 import static java.lang.invoke.LambdaForm.BasicType.*;
  31 import static java.lang.invoke.MethodHandleStatics.*;
  32 
  33 import java.lang.invoke.LambdaForm.NamedFunction;
  34 import java.lang.invoke.MethodHandles.Lookup;
  35 import java.lang.reflect.Field;
  36 import java.util.Arrays;
  37 import java.util.HashMap;


  38 

  39 import sun.invoke.util.ValueConversions;
  40 import sun.invoke.util.Wrapper;
  41 
  42 import jdk.internal.org.objectweb.asm.ClassWriter;
  43 import jdk.internal.org.objectweb.asm.MethodVisitor;
  44 import jdk.internal.org.objectweb.asm.Type;
  45 
  46 /**
  47  * The flavor of method handle which emulates an invoke instruction
  48  * on a predetermined argument.  The JVM dispatches to the correct method
  49  * when the handle is created, not when it is invoked.
  50  *
  51  * All bound arguments are encapsulated in dedicated species.
  52  */
  53 /*non-public*/ abstract class BoundMethodHandle extends MethodHandle {
  54 
  55     /*non-public*/ BoundMethodHandle(MethodType type, LambdaForm form) {
  56         super(type, form);
  57         assert(speciesData() == speciesData(form));
  58     }
  59 
  60     //
  61     // BMH API and internals
  62     //
  63 
  64     static BoundMethodHandle bindSingle(MethodType type, LambdaForm form, BasicType xtype, Object x) {


 200 
 201     //
 202     // concrete BMH classes required to close bootstrap loops
 203     //
 204 
 205     private  // make it private to force users to access the enclosing class first
 206     static final class Species_L extends BoundMethodHandle {
 207         final Object argL0;
 208         private Species_L(MethodType mt, LambdaForm lf, Object argL0) {
 209             super(mt, lf);
 210             this.argL0 = argL0;
 211         }
 212         @Override
 213         /*non-public*/ SpeciesData speciesData() {
 214             return SPECIES_DATA;
 215         }
 216         @Override
 217         /*non-public*/ int fieldCount() {
 218             return 1;
 219         }
 220         /*non-public*/ static final SpeciesData SPECIES_DATA = SpeciesData.getForClass("L", Species_L.class);
 221         /*non-public*/ static BoundMethodHandle make(MethodType mt, LambdaForm lf, Object argL0) {
 222             return new Species_L(mt, lf, argL0);
 223         }
 224         @Override
 225         /*non-public*/ final BoundMethodHandle copyWith(MethodType mt, LambdaForm lf) {
 226             return new Species_L(mt, lf, argL0);
 227         }
 228         @Override
 229         /*non-public*/ final BoundMethodHandle copyWithExtendL(MethodType mt, LambdaForm lf, Object narg) {
 230             try {
 231                 return (BoundMethodHandle) SPECIES_DATA.extendWith(L_TYPE).constructor().invokeBasic(mt, lf, argL0, narg);
 232             } catch (Throwable ex) {
 233                 throw uncaughtException(ex);
 234             }
 235         }
 236         @Override
 237         /*non-public*/ final BoundMethodHandle copyWithExtendI(MethodType mt, LambdaForm lf, int narg) {
 238             try {
 239                 return (BoundMethodHandle) SPECIES_DATA.extendWith(I_TYPE).constructor().invokeBasic(mt, lf, argL0, narg);
 240             } catch (Throwable ex) {


 318          */
 319         NamedFunction getterFunction(int i) {
 320             NamedFunction nf = nominalGetters[i];
 321             assert(nf.memberDeclaringClassOrNull() == fieldHolder());
 322             assert(nf.returnType() == fieldType(i));
 323             return nf;
 324         }
 325 
 326         NamedFunction[] getterFunctions() {
 327             return nominalGetters;
 328         }
 329 
 330         MethodHandle[] getterHandles() { return getters; }
 331 
 332         MethodHandle constructor() {
 333             return constructor[0];
 334         }
 335 
 336         static final SpeciesData EMPTY = new SpeciesData("", BoundMethodHandle.class);
 337 
 338         private SpeciesData(String types, Class<? extends BoundMethodHandle> clazz) {
 339             this.typeChars = types;
 340             this.typeCodes = basicTypes(types);
 341             this.clazz = clazz;
 342             if (!INIT_DONE) {
 343                 this.constructor = new MethodHandle[1];  // only one ctor
 344                 this.getters = new MethodHandle[types.length()];
 345                 this.nominalGetters = new NamedFunction[types.length()];
 346             } else {
 347                 this.constructor = Factory.makeCtors(clazz, types, null);
 348                 this.getters = Factory.makeGetters(clazz, types, null);
 349                 this.nominalGetters = Factory.makeNominalGetters(types, null, this.getters);
 350             }
 351             this.extensions = new SpeciesData[ARG_TYPE_LIMIT];
 352         }
 353 
 354         private void initForBootstrap() {
 355             assert(!INIT_DONE);
 356             if (constructor() == null) {
 357                 String types = typeChars;

 358                 Factory.makeCtors(clazz, types, this.constructor);
 359                 Factory.makeGetters(clazz, types, this.getters);
 360                 Factory.makeNominalGetters(types, this.nominalGetters, this.getters);
 361             }
 362         }
 363 
 364         private SpeciesData(String typeChars) {
 365             // Placeholder only.
 366             this.typeChars = typeChars;
 367             this.typeCodes = basicTypes(typeChars);
 368             this.clazz = null;
 369             this.constructor = null;
 370             this.getters = null;
 371             this.nominalGetters = null;
 372             this.extensions = null;
 373         }
 374         private boolean isPlaceholder() { return clazz == null; }
 375 
 376         private static final HashMap<String, SpeciesData> CACHE = new HashMap<>();
 377         static { CACHE.put("", EMPTY); }  // make bootstrap predictable
 378         private static final boolean INIT_DONE;  // set after <clinit> finishes...
 379 
 380         SpeciesData extendWith(byte type) {
 381             return extendWith(BasicType.basicType(type));
 382         }
 383 
 384         SpeciesData extendWith(BasicType type) {
 385             int ord = type.ordinal();
 386             SpeciesData d = extensions[ord];
 387             if (d != null)  return d;
 388             extensions[ord] = d = get(typeChars+type.basicTypeChar());
 389             return d;
 390         }
 391 
 392         private static SpeciesData get(String types) {
 393             // Acquire cache lock for query.
 394             SpeciesData d = lookupCache(types);
 395             if (!d.isPlaceholder())
 396                 return d;
 397             synchronized (d) {
 398                 // Use synch. on the placeholder to prevent multiple instantiation of one species.
 399                 // Creating this class forces a recursive call to getForClass.
 400                 if (lookupCache(types).isPlaceholder())
 401                     Factory.generateConcreteBMHClass(types);
 402             }
 403             // Reacquire cache lock.
 404             d = lookupCache(types);
 405             // Class loading must have upgraded the cache.
 406             assert(d != null && !d.isPlaceholder());
 407             return d;
 408         }
 409         static SpeciesData getForClass(String types, Class<? extends BoundMethodHandle> clazz) {
 410             // clazz is a new class which is initializing its SPECIES_DATA field
 411             return updateCache(types, new SpeciesData(types, clazz));
 412         }
 413         private static synchronized SpeciesData lookupCache(String types) {
 414             SpeciesData d = CACHE.get(types);
 415             if (d != null)  return d;
 416             d = new SpeciesData(types);
 417             assert(d.isPlaceholder());
 418             CACHE.put(types, d);
 419             return d;
 420         }
 421         private static synchronized SpeciesData updateCache(String types, SpeciesData d) {
 422             SpeciesData d2;
 423             assert((d2 = CACHE.get(types)) == null || d2.isPlaceholder());
 424             assert(!d.isPlaceholder());
 425             CACHE.put(types, d);
 426             return d;
 427         }
 428 
 429         static {
 430             // pre-fill the BMH speciesdata cache with BMH's inner classes
 431             final Class<BoundMethodHandle> rootCls = BoundMethodHandle.class;




 432             try {
 433                 for (Class<?> c : rootCls.getDeclaredClasses()) {
 434                     if (rootCls.isAssignableFrom(c)) {
 435                         final Class<? extends BoundMethodHandle> cbmh = c.asSubclass(BoundMethodHandle.class);
 436                         SpeciesData d = Factory.speciesDataFromConcreteBMHClass(cbmh);
 437                         assert(d != null) : cbmh.getName();
 438                         assert(d.clazz == cbmh);
 439                         assert(d == lookupCache(d.typeChars));
 440                     }
 441                 }
 442             } catch (Throwable e) {
 443                 throw newInternalError(e);
 444             }
 445 
 446             for (SpeciesData d : CACHE.values()) {
 447                 d.initForBootstrap();
 448             }







 449             // Note:  Do not simplify this, because INIT_DONE must not be
 450             // a compile-time constant during bootstrapping.
 451             INIT_DONE = Boolean.TRUE;
 452         }
 453     }
 454 
 455     static SpeciesData getSpeciesData(String types) {
 456         return SpeciesData.get(types);
 457     }
 458 
 459     /**
 460      * Generation of concrete BMH classes.
 461      *
 462      * A concrete BMH species is fit for binding a number of values adhering to a
 463      * given type pattern. Reference types are erased.
 464      *
 465      * BMH species are cached by type pattern.
 466      *
 467      * A BMH species has a number of fields with the concrete (possibly erased) types of
 468      * bound values. Setters are provided as an API in BMH. Getters are exposed as MHs,
 469      * which can be included as names in lambda forms.
 470      */
 471     static class Factory {
 472 
 473         static final String JLO_SIG  = "Ljava/lang/Object;";
 474         static final String JLS_SIG  = "Ljava/lang/String;";
 475         static final String JLC_SIG  = "Ljava/lang/Class;";
 476         static final String MH       = "java/lang/invoke/MethodHandle";
 477         static final String MH_SIG   = "L"+MH+";";
 478         static final String BMH      = "java/lang/invoke/BoundMethodHandle";
 479         static final String BMH_SIG  = "L"+BMH+";";
 480         static final String SPECIES_DATA     = "java/lang/invoke/BoundMethodHandle$SpeciesData";
 481         static final String SPECIES_DATA_SIG = "L"+SPECIES_DATA+";";

 482 
 483         static final String SPECIES_PREFIX_NAME = "Species_";
 484         static final String SPECIES_PREFIX_PATH = BMH + "$" + SPECIES_PREFIX_NAME;
 485 
 486         static final String BMHSPECIES_DATA_EWI_SIG = "(B)" + SPECIES_DATA_SIG;
 487         static final String BMHSPECIES_DATA_GFC_SIG = "(" + JLS_SIG + JLC_SIG + ")" + SPECIES_DATA_SIG;
 488         static final String MYSPECIES_DATA_SIG = "()" + SPECIES_DATA_SIG;
 489         static final String VOID_SIG   = "()V";
 490         static final String INT_SIG    = "()I";
 491 
 492         static final String SIG_INCIPIT = "(Ljava/lang/invoke/MethodType;Ljava/lang/invoke/LambdaForm;";
 493 
 494         static final String[] E_THROWABLE = new String[] { "java/lang/Throwable" };
 495 




















 496         /**
 497          * Generate a concrete subclass of BMH for a given combination of bound types.
 498          *
 499          * A concrete BMH species adheres to the following schema:
 500          *
 501          * <pre>
 502          * class Species_[[types]] extends BoundMethodHandle {
 503          *     [[fields]]
 504          *     final SpeciesData speciesData() { return SpeciesData.get("[[types]]"); }
 505          * }
 506          * </pre>
 507          *
 508          * The {@code [[types]]} signature is precisely the string that is passed to this
 509          * method.
 510          *
 511          * The {@code [[fields]]} section consists of one field definition per character in
 512          * the type signature, adhering to the naming schema described in the definition of
 513          * {@link #makeFieldName}.
 514          *
 515          * For example, a concrete BMH species for two reference and one integral bound values
 516          * would have the following shape:
 517          *
 518          * <pre>
 519          * class BoundMethodHandle { ... private static
 520          * final class Species_LLI extends BoundMethodHandle {
 521          *     final Object argL0;
 522          *     final Object argL1;
 523          *     final int argI2;
 524          *     private Species_LLI(MethodType mt, LambdaForm lf, Object argL0, Object argL1, int argI2) {
 525          *         super(mt, lf);
 526          *         this.argL0 = argL0;
 527          *         this.argL1 = argL1;
 528          *         this.argI2 = argI2;
 529          *     }
 530          *     final SpeciesData speciesData() { return SPECIES_DATA; }
 531          *     final int fieldCount() { return 3; }
 532          *     static final SpeciesData SPECIES_DATA = SpeciesData.getForClass("LLI", Species_LLI.class);
 533          *     static BoundMethodHandle make(MethodType mt, LambdaForm lf, Object argL0, Object argL1, int argI2) {
 534          *         return new Species_LLI(mt, lf, argL0, argL1, argI2);
 535          *     }
 536          *     final BoundMethodHandle copyWith(MethodType mt, LambdaForm lf) {
 537          *         return new Species_LLI(mt, lf, argL0, argL1, argI2);
 538          *     }
 539          *     final BoundMethodHandle copyWithExtendL(MethodType mt, LambdaForm lf, Object narg) {
 540          *         return SPECIES_DATA.extendWith(L_TYPE).constructor().invokeBasic(mt, lf, argL0, argL1, argI2, narg);
 541          *     }
 542          *     final BoundMethodHandle copyWithExtendI(MethodType mt, LambdaForm lf, int narg) {
 543          *         return SPECIES_DATA.extendWith(I_TYPE).constructor().invokeBasic(mt, lf, argL0, argL1, argI2, narg);
 544          *     }
 545          *     final BoundMethodHandle copyWithExtendJ(MethodType mt, LambdaForm lf, long narg) {
 546          *         return SPECIES_DATA.extendWith(J_TYPE).constructor().invokeBasic(mt, lf, argL0, argL1, argI2, narg);
 547          *     }
 548          *     final BoundMethodHandle copyWithExtendF(MethodType mt, LambdaForm lf, float narg) {
 549          *         return SPECIES_DATA.extendWith(F_TYPE).constructor().invokeBasic(mt, lf, argL0, argL1, argI2, narg);
 550          *     }
 551          *     public final BoundMethodHandle copyWithExtendD(MethodType mt, LambdaForm lf, double narg) {
 552          *         return SPECIES_DATA.extendWith(D_TYPE).constructor().invokeBasic(mt, lf, argL0, argL1, argI2, narg);
 553          *     }
 554          * }
 555          * </pre>
 556          *
 557          * @param types the type signature, wherein reference types are erased to 'L'
 558          * @return the generated concrete BMH class
 559          */
 560         static Class<? extends BoundMethodHandle> generateConcreteBMHClass(String types) {
 561             final ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
 562 
 563             String shortTypes = LambdaForm.shortenSignature(types);
 564             final String className  = SPECIES_PREFIX_PATH + shortTypes;
 565             final String sourceFile = SPECIES_PREFIX_NAME + shortTypes;
 566             final int NOT_ACC_PUBLIC = 0;  // not ACC_PUBLIC
 567             cw.visit(V1_6, NOT_ACC_PUBLIC + ACC_FINAL + ACC_SUPER, className, null, BMH, null);
 568             cw.visitSource(sourceFile, null);
 569 
 570             // emit static types and SPECIES_DATA fields
 571             cw.visitField(NOT_ACC_PUBLIC + ACC_STATIC, "SPECIES_DATA", SPECIES_DATA_SIG, null, null).visitEnd();


 572 
 573             // emit bound argument fields
 574             for (int i = 0; i < types.length(); ++i) {
 575                 final char t = types.charAt(i);
 576                 final String fieldName = makeFieldName(types, i);
 577                 final String fieldDesc = t == 'L' ? JLO_SIG : String.valueOf(t);
 578                 cw.visitField(ACC_FINAL, fieldName, fieldDesc, null, null).visitEnd();
 579             }
 580 
 581             MethodVisitor mv;
 582 
 583             // emit constructor
 584             mv = cw.visitMethod(ACC_PRIVATE, "<init>", makeSignature(types, true), null, null);
 585             mv.visitCode();
 586             mv.visitVarInsn(ALOAD, 0); // this
 587             mv.visitVarInsn(ALOAD, 1); // type
 588             mv.visitVarInsn(ALOAD, 2); // form
 589 
 590             mv.visitMethodInsn(INVOKESPECIAL, BMH, "<init>", makeSignature("", true), false);
 591 


 677                 mv.visitFieldInsn(GETSTATIC, className, "SPECIES_DATA", SPECIES_DATA_SIG);
 678                 int iconstInsn = ICONST_0 + ord;
 679                 assert(iconstInsn <= ICONST_5);
 680                 mv.visitInsn(iconstInsn);
 681                 mv.visitMethodInsn(INVOKEVIRTUAL, SPECIES_DATA, "extendWith", BMHSPECIES_DATA_EWI_SIG, false);
 682                 mv.visitMethodInsn(INVOKEVIRTUAL, SPECIES_DATA, "constructor", "()" + MH_SIG, false);
 683                 // load mt, lf
 684                 mv.visitVarInsn(ALOAD, 1);
 685                 mv.visitVarInsn(ALOAD, 2);
 686                 // put fields on the stack
 687                 emitPushFields(types, className, mv);
 688                 // put narg on stack
 689                 mv.visitVarInsn(typeLoadOp(btChar), 3);
 690                 // finally, invoke the constructor and return
 691                 mv.visitMethodInsn(INVOKEVIRTUAL, MH, "invokeBasic", makeSignature(types + btChar, false), false);
 692                 mv.visitInsn(ARETURN);
 693                 mv.visitMaxs(0, 0);
 694                 mv.visitEnd();
 695             }
 696 
 697             // emit class initializer
 698             mv = cw.visitMethod(NOT_ACC_PUBLIC | ACC_STATIC, "<clinit>", VOID_SIG, null, null);
 699             mv.visitCode();
 700             mv.visitLdcInsn(types);
 701             mv.visitLdcInsn(Type.getObjectType(className));
 702             mv.visitMethodInsn(INVOKESTATIC, SPECIES_DATA, "getForClass", BMHSPECIES_DATA_GFC_SIG, false);
 703             mv.visitFieldInsn(PUTSTATIC, className, "SPECIES_DATA", SPECIES_DATA_SIG);
 704             mv.visitInsn(RETURN);
 705             mv.visitMaxs(0, 0);
 706             mv.visitEnd();
 707 
 708             cw.visitEnd();
 709 
 710             // load class
 711             final byte[] classFile = cw.toByteArray();
 712             InvokerBytecodeGenerator.maybeDump(className, classFile);
 713             Class<? extends BoundMethodHandle> bmhClass =
 714                 //UNSAFE.defineAnonymousClass(BoundMethodHandle.class, classFile, null).asSubclass(BoundMethodHandle.class);
 715                 UNSAFE.defineClass(className, classFile, 0, classFile.length,
 716                                    BoundMethodHandle.class.getClassLoader(), null)
 717                     .asSubclass(BoundMethodHandle.class);
 718             UNSAFE.ensureClassInitialized(bmhClass);
 719 
 720             return bmhClass;
 721         }
 722 
 723         private static int typeLoadOp(char t) {
 724             switch (t) {
 725             case 'L': return ALOAD;
 726             case 'I': return ILOAD;
 727             case 'J': return LLOAD;
 728             case 'F': return FLOAD;
 729             case 'D': return DLOAD;
 730             default : throw newInternalError("unrecognized type " + t);
 731             }
 732         }
 733 
 734         private static void emitPushFields(String types, String className, MethodVisitor mv) {
 735             for (int i = 0; i < types.length(); ++i) {
 736                 char tc = types.charAt(i);
 737                 mv.visitVarInsn(ALOAD, 0);
 738                 mv.visitFieldInsn(GETFIELD, className, makeFieldName(types, i), typeSig(tc));


 768 
 769         static MethodHandle[] makeCtors(Class<? extends BoundMethodHandle> cbmh, String types, MethodHandle mhs[]) {
 770             if (mhs == null)  mhs = new MethodHandle[1];
 771             if (types.equals(""))  return mhs;  // hack for empty BMH species
 772             mhs[0] = makeCbmhCtor(cbmh, types);
 773             return mhs;
 774         }
 775 
 776         static NamedFunction[] makeNominalGetters(String types, NamedFunction[] nfs, MethodHandle[] getters) {
 777             if (nfs == null)  nfs = new NamedFunction[types.length()];
 778             for (int i = 0; i < nfs.length; ++i) {
 779                 nfs[i] = new NamedFunction(getters[i]);
 780             }
 781             return nfs;
 782         }
 783 
 784         //
 785         // Auxiliary methods.
 786         //
 787 
 788         static SpeciesData speciesDataFromConcreteBMHClass(Class<? extends BoundMethodHandle> cbmh) {
 789             try {
 790                 Field F_SPECIES_DATA = cbmh.getDeclaredField("SPECIES_DATA");
 791                 return (SpeciesData) F_SPECIES_DATA.get(null);










 792             } catch (ReflectiveOperationException ex) {
 793                 throw newInternalError(ex);
 794             }
 795         }
 796 
 797         /**
 798          * Field names in concrete BMHs adhere to this pattern:
 799          * arg + type + index
 800          * where type is a single character (L, I, J, F, D).
 801          */
 802         private static String makeFieldName(String types, int index) {
 803             assert index >= 0 && index < types.length();
 804             return "arg" + types.charAt(index) + index;
 805         }
 806 
 807         private static String makeSignature(String types, boolean ctor) {
 808             StringBuilder buf = new StringBuilder(SIG_INCIPIT);
 809             for (char c : types.toCharArray()) {
 810                 buf.append(typeSig(c));
 811             }




  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.*;
  30 import static java.lang.invoke.LambdaForm.BasicType.*;
  31 import static java.lang.invoke.MethodHandleStatics.*;
  32 
  33 import java.lang.invoke.LambdaForm.NamedFunction;
  34 import java.lang.invoke.MethodHandles.Lookup;
  35 import java.lang.reflect.Field;
  36 import java.util.Arrays;
  37 import java.util.function.Function;
  38 import java.util.concurrent.ConcurrentMap;
  39 import java.util.concurrent.ConcurrentHashMap;
  40 
  41 import jdk.internal.org.objectweb.asm.FieldVisitor;
  42 import sun.invoke.util.ValueConversions;
  43 import sun.invoke.util.Wrapper;
  44 
  45 import jdk.internal.org.objectweb.asm.ClassWriter;
  46 import jdk.internal.org.objectweb.asm.MethodVisitor;

  47 
  48 /**
  49  * The flavor of method handle which emulates an invoke instruction
  50  * on a predetermined argument.  The JVM dispatches to the correct method
  51  * when the handle is created, not when it is invoked.
  52  *
  53  * All bound arguments are encapsulated in dedicated species.
  54  */
  55 /*non-public*/ abstract class BoundMethodHandle extends MethodHandle {
  56 
  57     /*non-public*/ BoundMethodHandle(MethodType type, LambdaForm form) {
  58         super(type, form);
  59         assert(speciesData() == speciesData(form));
  60     }
  61 
  62     //
  63     // BMH API and internals
  64     //
  65 
  66     static BoundMethodHandle bindSingle(MethodType type, LambdaForm form, BasicType xtype, Object x) {


 202 
 203     //
 204     // concrete BMH classes required to close bootstrap loops
 205     //
 206 
 207     private  // make it private to force users to access the enclosing class first
 208     static final class Species_L extends BoundMethodHandle {
 209         final Object argL0;
 210         private Species_L(MethodType mt, LambdaForm lf, Object argL0) {
 211             super(mt, lf);
 212             this.argL0 = argL0;
 213         }
 214         @Override
 215         /*non-public*/ SpeciesData speciesData() {
 216             return SPECIES_DATA;
 217         }
 218         @Override
 219         /*non-public*/ int fieldCount() {
 220             return 1;
 221         }
 222         /*non-public*/ static final SpeciesData SPECIES_DATA = new SpeciesData("L", Species_L.class);
 223         /*non-public*/ static BoundMethodHandle make(MethodType mt, LambdaForm lf, Object argL0) {
 224             return new Species_L(mt, lf, argL0);
 225         }
 226         @Override
 227         /*non-public*/ final BoundMethodHandle copyWith(MethodType mt, LambdaForm lf) {
 228             return new Species_L(mt, lf, argL0);
 229         }
 230         @Override
 231         /*non-public*/ final BoundMethodHandle copyWithExtendL(MethodType mt, LambdaForm lf, Object narg) {
 232             try {
 233                 return (BoundMethodHandle) SPECIES_DATA.extendWith(L_TYPE).constructor().invokeBasic(mt, lf, argL0, narg);
 234             } catch (Throwable ex) {
 235                 throw uncaughtException(ex);
 236             }
 237         }
 238         @Override
 239         /*non-public*/ final BoundMethodHandle copyWithExtendI(MethodType mt, LambdaForm lf, int narg) {
 240             try {
 241                 return (BoundMethodHandle) SPECIES_DATA.extendWith(I_TYPE).constructor().invokeBasic(mt, lf, argL0, narg);
 242             } catch (Throwable ex) {


 320          */
 321         NamedFunction getterFunction(int i) {
 322             NamedFunction nf = nominalGetters[i];
 323             assert(nf.memberDeclaringClassOrNull() == fieldHolder());
 324             assert(nf.returnType() == fieldType(i));
 325             return nf;
 326         }
 327 
 328         NamedFunction[] getterFunctions() {
 329             return nominalGetters;
 330         }
 331 
 332         MethodHandle[] getterHandles() { return getters; }
 333 
 334         MethodHandle constructor() {
 335             return constructor[0];
 336         }
 337 
 338         static final SpeciesData EMPTY = new SpeciesData("", BoundMethodHandle.class);
 339 
 340         SpeciesData(String types, Class<? extends BoundMethodHandle> clazz) {
 341             this.typeChars = types;
 342             this.typeCodes = basicTypes(types);
 343             this.clazz = clazz;
 344             if (!INIT_DONE) {
 345                 this.constructor = new MethodHandle[1];  // only one ctor
 346                 this.getters = new MethodHandle[types.length()];
 347                 this.nominalGetters = new NamedFunction[types.length()];
 348             } else {
 349                 this.constructor = Factory.makeCtors(clazz, types, null);
 350                 this.getters = Factory.makeGetters(clazz, types, null);
 351                 this.nominalGetters = Factory.makeNominalGetters(types, null, this.getters);
 352             }
 353             this.extensions = new SpeciesData[ARG_TYPE_LIMIT];
 354         }
 355 
 356         private void initForBootstrap() {
 357             assert(!INIT_DONE);
 358             if (constructor() == null) {
 359                 String types = typeChars;
 360                 CACHE.put(types, this);
 361                 Factory.makeCtors(clazz, types, this.constructor);
 362                 Factory.makeGetters(clazz, types, this.getters);
 363                 Factory.makeNominalGetters(types, this.nominalGetters, this.getters);
 364             }
 365         }
 366 
 367         private static final ConcurrentMap<String, SpeciesData> CACHE = new ConcurrentHashMap<>();













 368         private static final boolean INIT_DONE;  // set after <clinit> finishes...
 369 
 370         SpeciesData extendWith(byte type) {
 371             return extendWith(BasicType.basicType(type));
 372         }
 373 
 374         SpeciesData extendWith(BasicType type) {
 375             int ord = type.ordinal();
 376             SpeciesData d = extensions[ord];
 377             if (d != null)  return d;
 378             extensions[ord] = d = get(typeChars+type.basicTypeChar());
 379             return d;
 380         }
 381 
 382         private static SpeciesData get(String types) {
 383             return CACHE.computeIfAbsent(types, new Function<String, SpeciesData>() {
 384                 @Override
 385                 public SpeciesData apply(String types) {
 386                     Class<? extends BoundMethodHandle> bmhcl = Factory.getConcreteBMHClass(types);
 387                     // SpeciesData instantiation may throw VirtualMachineError because of
 388                     // code cache overflow...
 389                     SpeciesData speciesData = new SpeciesData(types, bmhcl);
 390                     // CHM.computeIfAbsent ensures only one SpeciesData will be set
 391                     // successfully on the concrete BMH class if ever
 392                     Factory.setSpeciesDataToConcreteBMHClass(bmhcl, speciesData);
 393                     // the concrete BMH class is published via SpeciesData instance
 394                     // returned here only after it's SPECIES_DATA field is set
 395                     return speciesData;














 396                 }
 397             });





 398         }
 399 
 400         /**
 401          * This is to be called when assertions are enabled. It checks whether SpeciesData for all of the statically
 402          * defined species subclasses of BoundMethodHandle has been added to the SpeciesData cache. See below in the
 403          * static initializer for
 404          */
 405         static boolean speciesDataCachePopulated() {
 406             Class<BoundMethodHandle> rootCls = BoundMethodHandle.class;
 407             try {
 408                 for (Class<?> c : rootCls.getDeclaredClasses()) {
 409                     if (rootCls.isAssignableFrom(c)) {
 410                         final Class<? extends BoundMethodHandle> cbmh = c.asSubclass(BoundMethodHandle.class);
 411                         SpeciesData d = Factory.getSpeciesDataFromConcreteBMHClass(cbmh);
 412                         assert(d != null) : cbmh.getName();
 413                         assert(d.clazz == cbmh);
 414                         assert(CACHE.get(d.typeChars) == d);
 415                     }
 416                 }
 417             } catch (Throwable e) {
 418                 throw newInternalError(e);
 419             }
 420             return true;


 421         }
 422 
 423         static {
 424             // Pre-fill the BMH species-data cache with EMPTY and all BMH's inner subclasses.
 425             EMPTY.initForBootstrap();
 426             Species_L.SPECIES_DATA.initForBootstrap();
 427             // check that all static SpeciesData instances have been initialized
 428             assert speciesDataCachePopulated();
 429             // Note:  Do not simplify this, because INIT_DONE must not be
 430             // a compile-time constant during bootstrapping.
 431             INIT_DONE = Boolean.TRUE;
 432         }
 433     }
 434 
 435     static SpeciesData getSpeciesData(String types) {
 436         return SpeciesData.get(types);
 437     }
 438 
 439     /**
 440      * Generation of concrete BMH classes.
 441      *
 442      * A concrete BMH species is fit for binding a number of values adhering to a
 443      * given type pattern. Reference types are erased.
 444      *
 445      * BMH species are cached by type pattern.
 446      *
 447      * A BMH species has a number of fields with the concrete (possibly erased) types of
 448      * bound values. Setters are provided as an API in BMH. Getters are exposed as MHs,
 449      * which can be included as names in lambda forms.
 450      */
 451     static class Factory {
 452 
 453         static final String JLO_SIG  = "Ljava/lang/Object;";
 454         static final String JLS_SIG  = "Ljava/lang/String;";
 455         static final String JLC_SIG  = "Ljava/lang/Class;";
 456         static final String MH       = "java/lang/invoke/MethodHandle";
 457         static final String MH_SIG   = "L"+MH+";";
 458         static final String BMH      = "java/lang/invoke/BoundMethodHandle";
 459         static final String BMH_SIG  = "L"+BMH+";";
 460         static final String SPECIES_DATA     = "java/lang/invoke/BoundMethodHandle$SpeciesData";
 461         static final String SPECIES_DATA_SIG = "L"+SPECIES_DATA+";";
 462         static final String STABLE_SIG       = "Ljava/lang/invoke/Stable;";
 463 
 464         static final String SPECIES_PREFIX_NAME = "Species_";
 465         static final String SPECIES_PREFIX_PATH = BMH + "$" + SPECIES_PREFIX_NAME;
 466 
 467         static final String BMHSPECIES_DATA_EWI_SIG = "(B)" + SPECIES_DATA_SIG;
 468         static final String BMHSPECIES_DATA_GFC_SIG = "(" + JLS_SIG + JLC_SIG + ")" + SPECIES_DATA_SIG;
 469         static final String MYSPECIES_DATA_SIG = "()" + SPECIES_DATA_SIG;
 470         static final String VOID_SIG   = "()V";
 471         static final String INT_SIG    = "()I";
 472 
 473         static final String SIG_INCIPIT = "(Ljava/lang/invoke/MethodType;Ljava/lang/invoke/LambdaForm;";
 474 
 475         static final String[] E_THROWABLE = new String[] { "java/lang/Throwable" };
 476 
 477         static final ConcurrentMap<String, Class<? extends BoundMethodHandle>> CLASS_CACHE = new ConcurrentHashMap<>();
 478 
 479         /**
 480          * Get a concrete subclass of BMH for a given combination of bound types.
 481          *
 482          * @param types the type signature, wherein reference types are erased to 'L'
 483          * @return the concrete BMH class
 484          */
 485         static Class<? extends BoundMethodHandle> getConcreteBMHClass(String types) {
 486             // CHM.computeIfAbsent ensures generateConcreteBMHClass is called
 487             // only once per key.
 488             return CLASS_CACHE.computeIfAbsent(
 489                 types, new Function<String, Class<? extends BoundMethodHandle>>() {
 490                     @Override
 491                     public Class<? extends BoundMethodHandle> apply(String types) {
 492                         return generateConcreteBMHClass(types);
 493                     }
 494                 });
 495         }
 496 
 497         /**
 498          * Generate a concrete subclass of BMH for a given combination of bound types.
 499          *
 500          * A concrete BMH species adheres to the following schema:
 501          *
 502          * <pre>
 503          * class Species_[[types]] extends BoundMethodHandle {
 504          *     [[fields]]
 505          *     final SpeciesData speciesData() { return SpeciesData.get("[[types]]"); }
 506          * }
 507          * </pre>
 508          *
 509          * The {@code [[types]]} signature is precisely the string that is passed to this
 510          * method.
 511          *
 512          * The {@code [[fields]]} section consists of one field definition per character in
 513          * the type signature, adhering to the naming schema described in the definition of
 514          * {@link #makeFieldName}.
 515          *
 516          * For example, a concrete BMH species for two reference and one integral bound values
 517          * would have the following shape:
 518          *
 519          * <pre>
 520          * class BoundMethodHandle { ... private static
 521          * final class Species_LLI extends BoundMethodHandle {
 522          *     final Object argL0;
 523          *     final Object argL1;
 524          *     final int argI2;
 525          *     private Species_LLI(MethodType mt, LambdaForm lf, Object argL0, Object argL1, int argI2) {
 526          *         super(mt, lf);
 527          *         this.argL0 = argL0;
 528          *         this.argL1 = argL1;
 529          *         this.argI2 = argI2;
 530          *     }
 531          *     final SpeciesData speciesData() { return SPECIES_DATA; }
 532          *     final int fieldCount() { return 3; }
 533          *     @Stable static SpeciesData SPECIES_DATA; // injected afterwards
 534          *     static BoundMethodHandle make(MethodType mt, LambdaForm lf, Object argL0, Object argL1, int argI2) {
 535          *         return new Species_LLI(mt, lf, argL0, argL1, argI2);
 536          *     }
 537          *     final BoundMethodHandle copyWith(MethodType mt, LambdaForm lf) {
 538          *         return new Species_LLI(mt, lf, argL0, argL1, argI2);
 539          *     }
 540          *     final BoundMethodHandle copyWithExtendL(MethodType mt, LambdaForm lf, Object narg) {
 541          *         return SPECIES_DATA.extendWith(L_TYPE).constructor().invokeBasic(mt, lf, argL0, argL1, argI2, narg);
 542          *     }
 543          *     final BoundMethodHandle copyWithExtendI(MethodType mt, LambdaForm lf, int narg) {
 544          *         return SPECIES_DATA.extendWith(I_TYPE).constructor().invokeBasic(mt, lf, argL0, argL1, argI2, narg);
 545          *     }
 546          *     final BoundMethodHandle copyWithExtendJ(MethodType mt, LambdaForm lf, long narg) {
 547          *         return SPECIES_DATA.extendWith(J_TYPE).constructor().invokeBasic(mt, lf, argL0, argL1, argI2, narg);
 548          *     }
 549          *     final BoundMethodHandle copyWithExtendF(MethodType mt, LambdaForm lf, float narg) {
 550          *         return SPECIES_DATA.extendWith(F_TYPE).constructor().invokeBasic(mt, lf, argL0, argL1, argI2, narg);
 551          *     }
 552          *     public final BoundMethodHandle copyWithExtendD(MethodType mt, LambdaForm lf, double narg) {
 553          *         return SPECIES_DATA.extendWith(D_TYPE).constructor().invokeBasic(mt, lf, argL0, argL1, argI2, narg);
 554          *     }
 555          * }
 556          * </pre>
 557          *
 558          * @param types the type signature, wherein reference types are erased to 'L'
 559          * @return the generated concrete BMH class
 560          */
 561         static Class<? extends BoundMethodHandle> generateConcreteBMHClass(String types) {
 562             final ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
 563 
 564             String shortTypes = LambdaForm.shortenSignature(types);
 565             final String className  = SPECIES_PREFIX_PATH + shortTypes;
 566             final String sourceFile = SPECIES_PREFIX_NAME + shortTypes;
 567             final int NOT_ACC_PUBLIC = 0;  // not ACC_PUBLIC
 568             cw.visit(V1_6, NOT_ACC_PUBLIC + ACC_FINAL + ACC_SUPER, className, null, BMH, null);
 569             cw.visitSource(sourceFile, null);
 570 
 571             // emit static types and SPECIES_DATA fields
 572             FieldVisitor fw = cw.visitField(NOT_ACC_PUBLIC + ACC_STATIC, "SPECIES_DATA", SPECIES_DATA_SIG, null, null);
 573             fw.visitAnnotation(STABLE_SIG, true);
 574             fw.visitEnd();
 575 
 576             // emit bound argument fields
 577             for (int i = 0; i < types.length(); ++i) {
 578                 final char t = types.charAt(i);
 579                 final String fieldName = makeFieldName(types, i);
 580                 final String fieldDesc = t == 'L' ? JLO_SIG : String.valueOf(t);
 581                 cw.visitField(ACC_FINAL, fieldName, fieldDesc, null, null).visitEnd();
 582             }
 583 
 584             MethodVisitor mv;
 585 
 586             // emit constructor
 587             mv = cw.visitMethod(ACC_PRIVATE, "<init>", makeSignature(types, true), null, null);
 588             mv.visitCode();
 589             mv.visitVarInsn(ALOAD, 0); // this
 590             mv.visitVarInsn(ALOAD, 1); // type
 591             mv.visitVarInsn(ALOAD, 2); // form
 592 
 593             mv.visitMethodInsn(INVOKESPECIAL, BMH, "<init>", makeSignature("", true), false);
 594 


 680                 mv.visitFieldInsn(GETSTATIC, className, "SPECIES_DATA", SPECIES_DATA_SIG);
 681                 int iconstInsn = ICONST_0 + ord;
 682                 assert(iconstInsn <= ICONST_5);
 683                 mv.visitInsn(iconstInsn);
 684                 mv.visitMethodInsn(INVOKEVIRTUAL, SPECIES_DATA, "extendWith", BMHSPECIES_DATA_EWI_SIG, false);
 685                 mv.visitMethodInsn(INVOKEVIRTUAL, SPECIES_DATA, "constructor", "()" + MH_SIG, false);
 686                 // load mt, lf
 687                 mv.visitVarInsn(ALOAD, 1);
 688                 mv.visitVarInsn(ALOAD, 2);
 689                 // put fields on the stack
 690                 emitPushFields(types, className, mv);
 691                 // put narg on stack
 692                 mv.visitVarInsn(typeLoadOp(btChar), 3);
 693                 // finally, invoke the constructor and return
 694                 mv.visitMethodInsn(INVOKEVIRTUAL, MH, "invokeBasic", makeSignature(types + btChar, false), false);
 695                 mv.visitInsn(ARETURN);
 696                 mv.visitMaxs(0, 0);
 697                 mv.visitEnd();
 698             }
 699 











 700             cw.visitEnd();
 701 
 702             // load class
 703             final byte[] classFile = cw.toByteArray();
 704             InvokerBytecodeGenerator.maybeDump(className, classFile);
 705             Class<? extends BoundMethodHandle> bmhClass =
 706                 //UNSAFE.defineAnonymousClass(BoundMethodHandle.class, classFile, null).asSubclass(BoundMethodHandle.class);
 707                 UNSAFE.defineClass(className, classFile, 0, classFile.length,
 708                                    BoundMethodHandle.class.getClassLoader(), null)
 709                     .asSubclass(BoundMethodHandle.class);

 710 
 711             return bmhClass;
 712         }
 713 
 714         private static int typeLoadOp(char t) {
 715             switch (t) {
 716             case 'L': return ALOAD;
 717             case 'I': return ILOAD;
 718             case 'J': return LLOAD;
 719             case 'F': return FLOAD;
 720             case 'D': return DLOAD;
 721             default : throw newInternalError("unrecognized type " + t);
 722             }
 723         }
 724 
 725         private static void emitPushFields(String types, String className, MethodVisitor mv) {
 726             for (int i = 0; i < types.length(); ++i) {
 727                 char tc = types.charAt(i);
 728                 mv.visitVarInsn(ALOAD, 0);
 729                 mv.visitFieldInsn(GETFIELD, className, makeFieldName(types, i), typeSig(tc));


 759 
 760         static MethodHandle[] makeCtors(Class<? extends BoundMethodHandle> cbmh, String types, MethodHandle mhs[]) {
 761             if (mhs == null)  mhs = new MethodHandle[1];
 762             if (types.equals(""))  return mhs;  // hack for empty BMH species
 763             mhs[0] = makeCbmhCtor(cbmh, types);
 764             return mhs;
 765         }
 766 
 767         static NamedFunction[] makeNominalGetters(String types, NamedFunction[] nfs, MethodHandle[] getters) {
 768             if (nfs == null)  nfs = new NamedFunction[types.length()];
 769             for (int i = 0; i < nfs.length; ++i) {
 770                 nfs[i] = new NamedFunction(getters[i]);
 771             }
 772             return nfs;
 773         }
 774 
 775         //
 776         // Auxiliary methods.
 777         //
 778 
 779         static SpeciesData getSpeciesDataFromConcreteBMHClass(Class<? extends BoundMethodHandle> cbmh) {
 780             try {
 781                 Field F_SPECIES_DATA = cbmh.getDeclaredField("SPECIES_DATA");
 782                 return (SpeciesData) F_SPECIES_DATA.get(null);
 783             } catch (ReflectiveOperationException ex) {
 784                 throw newInternalError(ex);
 785             }
 786         }
 787 
 788         static void setSpeciesDataToConcreteBMHClass(Class<? extends BoundMethodHandle> cbmh, SpeciesData speciesData) {
 789             try {
 790                 Field F_SPECIES_DATA = cbmh.getDeclaredField("SPECIES_DATA");
 791                 assert F_SPECIES_DATA.getDeclaredAnnotation(Stable.class) != null;
 792                 F_SPECIES_DATA.set(null, speciesData);
 793             } catch (ReflectiveOperationException ex) {
 794                 throw newInternalError(ex);
 795             }
 796         }
 797 
 798         /**
 799          * Field names in concrete BMHs adhere to this pattern:
 800          * arg + type + index
 801          * where type is a single character (L, I, J, F, D).
 802          */
 803         private static String makeFieldName(String types, int index) {
 804             assert index >= 0 && index < types.length();
 805             return "arg" + types.charAt(index) + index;
 806         }
 807 
 808         private static String makeSignature(String types, boolean ctor) {
 809             StringBuilder buf = new StringBuilder(SIG_INCIPIT);
 810             for (char c : types.toCharArray()) {
 811                 buf.append(typeSig(c));
 812             }


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