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

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 115                 return new StaticAccessor(mtype, lform, member, true, base, offset);
 116             } else {
 117                 long offset = MethodHandleNatives.objectFieldOffset(member);
 118                 assert(offset == (int)offset);
 119                 return new Accessor(mtype, lform, member, true, (int)offset);
 120             }
 121         }
 122     }
 123     static DirectMethodHandle make(Class<?> refc, MemberName member) {
 124         byte refKind = member.getReferenceKind();
 125         if (refKind == REF_invokeSpecial)
 126             refKind =  REF_invokeVirtual;
 127         return make(refKind, refc, member, null /* no callerClass context */);
 128     }
 129     static DirectMethodHandle make(MemberName member) {
 130         if (member.isConstructor())
 131             return makeAllocator(member.getDeclaringClass(), member);
 132         return make(member.getDeclaringClass(), member);
 133     }
 134     static DirectMethodHandle makeAllocator(Class<?> instanceClass, MemberName ctor) {
 135         assert(ctor.isConstructor() && ctor.getName().equals("<init>"));
 136         ctor = ctor.asConstructor();
 137         assert(ctor.isConstructor() && ctor.getReferenceKind() == REF_newInvokeSpecial) : ctor;
 138         MethodType mtype = ctor.getMethodType().changeReturnType(instanceClass);
 139         LambdaForm lform = preparedLambdaForm(ctor);
 140         MemberName init = ctor.asSpecial();
 141         assert(init.getMethodType().returnType() == void.class);
 142         return new Constructor(mtype, lform, ctor, true, init, instanceClass);
 143     }
 144 
 145     @Override
 146     BoundMethodHandle rebind() {
 147         return BoundMethodHandle.makeReinvoker(this);
 148     }
 149 
 150     @Override
 151     MethodHandle copyWith(MethodType mt, LambdaForm lf) {
 152         assert(this.getClass() == DirectMethodHandle.class);  // must override in subclasses
 153         return new DirectMethodHandle(mt, lf, member, crackable);
 154     }
 155 
 156     @Override
 157     MethodHandle viewAsType(MethodType newType, boolean strict) {

 587     }
 588 
 589     @ForceInline
 590     /*non-public*/
 591     static Object staticBase(Object accessorObj) {
 592         return ((StaticAccessor)accessorObj).staticBase;
 593     }
 594 
 595     @ForceInline
 596     /*non-public*/
 597     static long staticOffset(Object accessorObj) {
 598         return ((StaticAccessor)accessorObj).staticOffset;
 599     }
 600 
 601     @ForceInline
 602     /*non-public*/
 603     static Object checkCast(Object mh, Object obj) {
 604         return ((DirectMethodHandle) mh).checkCast(obj);
 605     }
 606 















 607     Object checkCast(Object obj) {
 608         return member.getMethodType().returnType().cast(obj);
 609     }
 610 
 611     // Caching machinery for field accessors:
 612     static final byte
 613             AF_GETFIELD        = 0,
 614             AF_PUTFIELD        = 1,
 615             AF_GETSTATIC       = 2,
 616             AF_PUTSTATIC       = 3,
 617             AF_GETSTATIC_INIT  = 4,
 618             AF_PUTSTATIC_INIT  = 5,
 619             AF_LIMIT           = 6;
 620     // Enumerate the different field kinds using Wrapper,
 621     // with an extra case added for checked references.
 622     static final int
 623             FT_LAST_WRAPPER    = Wrapper.COUNT-1,
 624             FT_UNCHECKED_REF   = Wrapper.OBJECT.ordinal(),
 625             FT_CHECKED_REF     = FT_LAST_WRAPPER+1,
 626             FT_LIMIT           = FT_LAST_WRAPPER+2;
 627     private static int afIndex(byte formOp, boolean isVolatile, int ftypeKind) {

 628         return ((formOp * FT_LIMIT * 2)
 629                 + (isVolatile ? FT_LIMIT : 0)


 630                 + ftypeKind);
 631     }
 632     @Stable
 633     private static final LambdaForm[] ACCESSOR_FORMS
 634             = new LambdaForm[afIndex(AF_LIMIT, false, 0)];
 635     static int ftypeKind(Class<?> ftype) {
 636         if (ftype.isPrimitive()) {
 637             return Wrapper.forPrimitiveType(ftype).ordinal();
 638         } else if (ftype.isInterface() || ftype.isAssignableFrom(Object.class)) {
 639             // retyping can be done without a cast
 640             return FT_UNCHECKED_REF;
 641         } else {
 642             return FT_CHECKED_REF;
 643         }
 644     }
 645 
 646     /**
 647      * Create a LF which can access the given field.
 648      * Cache and share this structure among all fields with
 649      * the same basicType and refKind.
 650      */
 651     private static LambdaForm preparedFieldLambdaForm(MemberName m) {
 652         Class<?> ftype = m.getFieldType();
 653         boolean isVolatile = m.isVolatile();
 654         byte formOp = switch (m.getReferenceKind()) {
 655             case REF_getField  -> AF_GETFIELD;
 656             case REF_putField  -> AF_PUTFIELD;
 657             case REF_getStatic -> AF_GETSTATIC;
 658             case REF_putStatic -> AF_PUTSTATIC;
 659             default -> throw new InternalError(m.toString());
 660         };
 661         if (shouldBeInitialized(m)) {
 662             // precompute the barrier-free version:
 663             preparedFieldLambdaForm(formOp, isVolatile, ftype);
 664             assert((AF_GETSTATIC_INIT - AF_GETSTATIC) ==
 665                    (AF_PUTSTATIC_INIT - AF_PUTSTATIC));
 666             formOp += (AF_GETSTATIC_INIT - AF_GETSTATIC);
 667         }
 668         LambdaForm lform = preparedFieldLambdaForm(formOp, isVolatile, ftype);
 669         maybeCompile(lform, m);
 670         assert(lform.methodType().dropParameterTypes(0, 1)
 671                 .equals(m.getInvocationType().basicType()))
 672                 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
 673         return lform;
 674     }
 675     private static LambdaForm preparedFieldLambdaForm(byte formOp, boolean isVolatile, Class<?> ftype) {


 676         int ftypeKind = ftypeKind(ftype);
 677         int afIndex = afIndex(formOp, isVolatile, ftypeKind);
 678         LambdaForm lform = ACCESSOR_FORMS[afIndex];
 679         if (lform != null)  return lform;
 680         lform = makePreparedFieldLambdaForm(formOp, isVolatile, ftypeKind);
 681         ACCESSOR_FORMS[afIndex] = lform;  // don't bother with a CAS
 682         return lform;
 683     }
 684 
 685     private static final Wrapper[] ALL_WRAPPERS = Wrapper.values();
 686 
 687     private static Kind getFieldKind(boolean isGetter, boolean isVolatile, Wrapper wrapper) {
 688         if (isGetter) {
 689             if (isVolatile) {
 690                 switch (wrapper) {
 691                     case BOOLEAN: return GET_BOOLEAN_VOLATILE;
 692                     case BYTE:    return GET_BYTE_VOLATILE;
 693                     case SHORT:   return GET_SHORT_VOLATILE;
 694                     case CHAR:    return GET_CHAR_VOLATILE;
 695                     case INT:     return GET_INT_VOLATILE;
 696                     case LONG:    return GET_LONG_VOLATILE;
 697                     case FLOAT:   return GET_FLOAT_VOLATILE;
 698                     case DOUBLE:  return GET_DOUBLE_VOLATILE;
 699                     case OBJECT:  return GET_REFERENCE_VOLATILE;
 700                 }
 701             } else {
 702                 switch (wrapper) {
 703                     case BOOLEAN: return GET_BOOLEAN;
 704                     case BYTE:    return GET_BYTE;
 705                     case SHORT:   return GET_SHORT;
 706                     case CHAR:    return GET_CHAR;
 707                     case INT:     return GET_INT;
 708                     case LONG:    return GET_LONG;
 709                     case FLOAT:   return GET_FLOAT;
 710                     case DOUBLE:  return GET_DOUBLE;
 711                     case OBJECT:  return GET_REFERENCE;
 712                 }
 713             }
 714         } else {
 715             if (isVolatile) {
 716                 switch (wrapper) {
 717                     case BOOLEAN: return PUT_BOOLEAN_VOLATILE;
 718                     case BYTE:    return PUT_BYTE_VOLATILE;
 719                     case SHORT:   return PUT_SHORT_VOLATILE;
 720                     case CHAR:    return PUT_CHAR_VOLATILE;
 721                     case INT:     return PUT_INT_VOLATILE;
 722                     case LONG:    return PUT_LONG_VOLATILE;
 723                     case FLOAT:   return PUT_FLOAT_VOLATILE;
 724                     case DOUBLE:  return PUT_DOUBLE_VOLATILE;
 725                     case OBJECT:  return PUT_REFERENCE_VOLATILE;
 726                 }
 727             } else {
 728                 switch (wrapper) {
 729                     case BOOLEAN: return PUT_BOOLEAN;
 730                     case BYTE:    return PUT_BYTE;
 731                     case SHORT:   return PUT_SHORT;
 732                     case CHAR:    return PUT_CHAR;
 733                     case INT:     return PUT_INT;
 734                     case LONG:    return PUT_LONG;
 735                     case FLOAT:   return PUT_FLOAT;
 736                     case DOUBLE:  return PUT_DOUBLE;
 737                     case OBJECT:  return PUT_REFERENCE;
 738                 }
 739             }
 740         }
 741         throw new AssertionError("Invalid arguments");
 742     }
 743 
 744     static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, int ftypeKind) {






 745         boolean isGetter  = (formOp & 1) == (AF_GETFIELD & 1);
 746         boolean isStatic  = (formOp >= AF_GETSTATIC);
 747         boolean needsInit = (formOp >= AF_GETSTATIC_INIT);
 748         boolean needsCast = (ftypeKind == FT_CHECKED_REF);
 749         Wrapper fw = (needsCast ? Wrapper.OBJECT : ALL_WRAPPERS[ftypeKind]);
 750         Class<?> ft = fw.primitiveType();
 751         assert(ftypeKind(needsCast ? String.class : ft) == ftypeKind);
 752 
 753         // getObject, putIntVolatile, etc.
 754         Kind kind = getFieldKind(isGetter, isVolatile, fw);
 755 
 756         MethodType linkerType;
 757         if (isGetter)
 758             linkerType = MethodType.methodType(ft, Object.class, long.class);
 759         else
 760             linkerType = MethodType.methodType(void.class, Object.class, long.class, ft);





 761         MemberName linker = new MemberName(Unsafe.class, kind.methodName, linkerType, REF_invokeVirtual);
 762         try {
 763             linker = IMPL_NAMES.resolveOrFail(REF_invokeVirtual, linker, null, LM_TRUSTED,
 764                                               NoSuchMethodException.class);
 765         } catch (ReflectiveOperationException ex) {
 766             throw newInternalError(ex);
 767         }
 768 
 769         // What is the external type of the lambda form?
 770         MethodType mtype;
 771         if (isGetter)
 772             mtype = MethodType.methodType(ft);
 773         else
 774             mtype = MethodType.methodType(void.class, ft);
 775         mtype = mtype.basicType();  // erase short to int, etc.
 776         if (!isStatic)
 777             mtype = mtype.insertParameterTypes(0, Object.class);
 778         final int DMH_THIS  = 0;
 779         final int ARG_BASE  = 1;
 780         final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
 781         // if this is for non-static access, the base pointer is stored at this index:
 782         final int OBJ_BASE  = isStatic ? -1 : ARG_BASE;
 783         // if this is for write access, the value to be written is stored at this index:
 784         final int SET_VALUE  = isGetter ? -1 : ARG_LIMIT - 1;
 785         int nameCursor = ARG_LIMIT;
 786         final int F_HOLDER  = (isStatic ? nameCursor++ : -1);  // static base if any
 787         final int F_OFFSET  = nameCursor++;  // Either static offset or field offset.
 788         final int OBJ_CHECK = (OBJ_BASE >= 0 ? nameCursor++ : -1);
 789         final int U_HOLDER  = nameCursor++;  // UNSAFE holder
 790         final int INIT_BAR  = (needsInit ? nameCursor++ : -1);


 791         final int PRE_CAST  = (needsCast && !isGetter ? nameCursor++ : -1);
 792         final int LINKER_CALL = nameCursor++;


 793         final int POST_CAST = (needsCast && isGetter ? nameCursor++ : -1);
 794         final int RESULT    = nameCursor-1;  // either the call or the cast
 795         Name[] names = invokeArguments(nameCursor - ARG_LIMIT, mtype);
 796         if (needsInit)
 797             names[INIT_BAR] = new Name(getFunction(NF_ensureInitialized), names[DMH_THIS]);
 798         if (needsCast && !isGetter)
 799             names[PRE_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[SET_VALUE]);




 800         Object[] outArgs = new Object[1 + linkerType.parameterCount()];
 801         assert(outArgs.length == (isGetter ? 3 : 4));
 802         outArgs[0] = names[U_HOLDER] = new Name(getFunction(NF_UNSAFE));
 803         if (isStatic) {
 804             outArgs[1] = names[F_HOLDER]  = new Name(getFunction(NF_staticBase), names[DMH_THIS]);
 805             outArgs[2] = names[F_OFFSET]  = new Name(getFunction(NF_staticOffset), names[DMH_THIS]);
 806         } else {
 807             outArgs[1] = names[OBJ_CHECK] = new Name(getFunction(NF_checkBase), names[OBJ_BASE]);
 808             outArgs[2] = names[F_OFFSET]  = new Name(getFunction(NF_fieldOffset), names[DMH_THIS]);
 809         }





 810         if (!isGetter) {
 811             outArgs[3] = (needsCast ? names[PRE_CAST] : names[SET_VALUE]);
 812         }
 813         for (Object a : outArgs)  assert(a != null);
 814         names[LINKER_CALL] = new Name(linker, outArgs);
 815         if (needsCast && isGetter)
 816             names[POST_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[LINKER_CALL]);









 817         for (Name n : names)  assert(n != null);
 818 
 819         LambdaForm form;
 820         if (needsCast || needsInit) {
 821             // can't use the pre-generated form when casting and/or initializing
 822             form = LambdaForm.create(ARG_LIMIT, names, RESULT);
 823         } else {
 824             form = LambdaForm.create(ARG_LIMIT, names, RESULT, kind);
 825         }
 826 
 827         if (LambdaForm.debugNames()) {
 828             // add some detail to the lambdaForm debugname,
 829             // significant only for debugging
 830             StringBuilder nameBuilder = new StringBuilder(kind.methodName);
 831             if (isStatic) {
 832                 nameBuilder.append("Static");
 833             } else {
 834                 nameBuilder.append("Field");
 835             }
 836             if (needsCast) {

 842             LambdaForm.associateWithDebugName(form, nameBuilder.toString());
 843         }
 844         return form;
 845     }
 846 
 847     /**
 848      * Pre-initialized NamedFunctions for bootstrapping purposes.
 849      */
 850     static final byte NF_internalMemberName = 0,
 851             NF_internalMemberNameEnsureInit = 1,
 852             NF_ensureInitialized = 2,
 853             NF_fieldOffset = 3,
 854             NF_checkBase = 4,
 855             NF_staticBase = 5,
 856             NF_staticOffset = 6,
 857             NF_checkCast = 7,
 858             NF_allocateInstance = 8,
 859             NF_constructorMethod = 9,
 860             NF_UNSAFE = 10,
 861             NF_checkReceiver = 11,
 862             NF_LIMIT = 12;




 863 
 864     private static final @Stable NamedFunction[] NFS = new NamedFunction[NF_LIMIT];
 865 
 866     private static NamedFunction getFunction(byte func) {
 867         NamedFunction nf = NFS[func];
 868         if (nf != null) {
 869             return nf;
 870         }
 871         // Each nf must be statically invocable or we get tied up in our bootstraps.
 872         nf = NFS[func] = createFunction(func);
 873         assert(InvokerBytecodeGenerator.isStaticallyInvocable(nf));
 874         return nf;
 875     }
 876 


 877     private static final MethodType OBJ_OBJ_TYPE = MethodType.methodType(Object.class, Object.class);
 878 
 879     private static final MethodType LONG_OBJ_TYPE = MethodType.methodType(long.class, Object.class);
 880 
 881     private static NamedFunction createFunction(byte func) {
 882         try {
 883             switch (func) {
 884                 case NF_internalMemberName:
 885                     return getNamedFunction("internalMemberName", OBJ_OBJ_TYPE);
 886                 case NF_internalMemberNameEnsureInit:
 887                     return getNamedFunction("internalMemberNameEnsureInit", OBJ_OBJ_TYPE);
 888                 case NF_ensureInitialized:
 889                     return getNamedFunction("ensureInitialized", MethodType.methodType(void.class, Object.class));
 890                 case NF_fieldOffset:
 891                     return getNamedFunction("fieldOffset", LONG_OBJ_TYPE);
 892                 case NF_checkBase:
 893                     return getNamedFunction("checkBase", OBJ_OBJ_TYPE);
 894                 case NF_staticBase:
 895                     return getNamedFunction("staticBase", OBJ_OBJ_TYPE);
 896                 case NF_staticOffset:
 897                     return getNamedFunction("staticOffset", LONG_OBJ_TYPE);
 898                 case NF_checkCast:
 899                     return getNamedFunction("checkCast", MethodType.methodType(Object.class, Object.class, Object.class));
 900                 case NF_allocateInstance:
 901                     return getNamedFunction("allocateInstance", OBJ_OBJ_TYPE);
 902                 case NF_constructorMethod:
 903                     return getNamedFunction("constructorMethod", OBJ_OBJ_TYPE);
 904                 case NF_UNSAFE:
 905                     MemberName member = new MemberName(MethodHandleStatics.class, "UNSAFE", Unsafe.class, REF_getStatic);
 906                     return new NamedFunction(
 907                             MemberName.getFactory().resolveOrFail(REF_getStatic, member,
 908                                                                   DirectMethodHandle.class, LM_TRUSTED,
 909                                                                   NoSuchFieldException.class));
 910                 case NF_checkReceiver:
 911                     member = new MemberName(DirectMethodHandle.class, "checkReceiver", OBJ_OBJ_TYPE, REF_invokeVirtual);
 912                     return new NamedFunction(
 913                             MemberName.getFactory().resolveOrFail(REF_invokeVirtual, member,
 914                                                                   DirectMethodHandle.class, LM_TRUSTED,
 915                                                                   NoSuchMethodException.class));








 916                 default:
 917                     throw newInternalError("Unknown function: " + func);
 918             }
 919         } catch (ReflectiveOperationException ex) {
 920             throw newInternalError(ex);
 921         }
 922     }
 923 
 924     private static NamedFunction getNamedFunction(String name, MethodType type)
 925         throws ReflectiveOperationException
 926     {
 927         MemberName member = new MemberName(DirectMethodHandle.class, name, type, REF_invokeStatic);
 928         return new NamedFunction(
 929                 MemberName.getFactory().resolveOrFail(REF_invokeStatic, member,
 930                                                       DirectMethodHandle.class, LM_TRUSTED,
 931                                                       NoSuchMethodException.class));
 932     }
 933 
 934     static {
 935         // The Holder class will contain pre-generated DirectMethodHandles resolved

 115                 return new StaticAccessor(mtype, lform, member, true, base, offset);
 116             } else {
 117                 long offset = MethodHandleNatives.objectFieldOffset(member);
 118                 assert(offset == (int)offset);
 119                 return new Accessor(mtype, lform, member, true, (int)offset);
 120             }
 121         }
 122     }
 123     static DirectMethodHandle make(Class<?> refc, MemberName member) {
 124         byte refKind = member.getReferenceKind();
 125         if (refKind == REF_invokeSpecial)
 126             refKind =  REF_invokeVirtual;
 127         return make(refKind, refc, member, null /* no callerClass context */);
 128     }
 129     static DirectMethodHandle make(MemberName member) {
 130         if (member.isConstructor())
 131             return makeAllocator(member.getDeclaringClass(), member);
 132         return make(member.getDeclaringClass(), member);
 133     }
 134     static DirectMethodHandle makeAllocator(Class<?> instanceClass, MemberName ctor) {
 135         assert(ctor.isConstructor()) : ctor;
 136         ctor = ctor.asConstructor();
 137         assert(ctor.getReferenceKind() == REF_newInvokeSpecial) : ctor;
 138         MethodType mtype = ctor.getMethodType().changeReturnType(instanceClass);
 139         LambdaForm lform = preparedLambdaForm(ctor);
 140         MemberName init = ctor.asSpecial();
 141         assert(init.getMethodType().returnType() == void.class);
 142         return new Constructor(mtype, lform, ctor, true, init, instanceClass);
 143     }
 144 
 145     @Override
 146     BoundMethodHandle rebind() {
 147         return BoundMethodHandle.makeReinvoker(this);
 148     }
 149 
 150     @Override
 151     MethodHandle copyWith(MethodType mt, LambdaForm lf) {
 152         assert(this.getClass() == DirectMethodHandle.class);  // must override in subclasses
 153         return new DirectMethodHandle(mt, lf, member, crackable);
 154     }
 155 
 156     @Override
 157     MethodHandle viewAsType(MethodType newType, boolean strict) {

 587     }
 588 
 589     @ForceInline
 590     /*non-public*/
 591     static Object staticBase(Object accessorObj) {
 592         return ((StaticAccessor)accessorObj).staticBase;
 593     }
 594 
 595     @ForceInline
 596     /*non-public*/
 597     static long staticOffset(Object accessorObj) {
 598         return ((StaticAccessor)accessorObj).staticOffset;
 599     }
 600 
 601     @ForceInline
 602     /*non-public*/
 603     static Object checkCast(Object mh, Object obj) {
 604         return ((DirectMethodHandle) mh).checkCast(obj);
 605     }
 606 
 607     @ForceInline
 608     /*non-public*/ static Class<?> fieldType(Object accessorObj) {
 609         return ((Accessor) accessorObj).fieldType;
 610     }
 611 
 612     @ForceInline
 613     /*non-public*/ static Class<?> staticFieldType(Object accessorObj) {
 614         return ((StaticAccessor) accessorObj).fieldType;
 615     }
 616 
 617     @ForceInline
 618     /*non-public*/ static Object zeroInstanceIfNull(Class<?> fieldType, Object obj) {
 619         return obj != null ? obj : UNSAFE.uninitializedDefaultValue(fieldType);
 620     }
 621 
 622     Object checkCast(Object obj) {
 623         return member.getMethodType().returnType().cast(obj);
 624     }
 625 
 626     // Caching machinery for field accessors:
 627     static final byte
 628             AF_GETFIELD        = 0,
 629             AF_PUTFIELD        = 1,
 630             AF_GETSTATIC       = 2,
 631             AF_PUTSTATIC       = 3,
 632             AF_GETSTATIC_INIT  = 4,
 633             AF_PUTSTATIC_INIT  = 5,
 634             AF_LIMIT           = 6;
 635     // Enumerate the different field kinds using Wrapper,
 636     // with an extra case added for checked references and value field access
 637     static final int
 638             FT_LAST_WRAPPER     = Wrapper.COUNT-1,
 639             FT_UNCHECKED_REF    = Wrapper.OBJECT.ordinal(),
 640             FT_CHECKED_REF      = FT_LAST_WRAPPER+1,
 641             FT_CHECKED_VALUE    = FT_LAST_WRAPPER+2,  // flat vs non-flat x null value vs null-restricted value
 642             FT_LIMIT            = FT_LAST_WRAPPER+6;
 643     private static int afIndex(byte formOp, boolean isVolatile, boolean isFlat, boolean isNullRestricted, int ftypeKind) {
 644         return ((formOp * FT_LIMIT * 2)
 645                 + (isVolatile ? FT_LIMIT : 0)
 646                 + (isFlat ? 1 : 0)
 647                 + (isNullRestricted ? 1 : 0)
 648                 + ftypeKind);
 649     }
 650     @Stable
 651     private static final LambdaForm[] ACCESSOR_FORMS
 652             = new LambdaForm[afIndex(AF_LIMIT, false, false, false, 0)];
 653     static int ftypeKind(Class<?> ftype) {
 654         if (ftype.isPrimitive()) {
 655             return Wrapper.forPrimitiveType(ftype).ordinal();
 656         } else if (ftype.isInterface() || ftype.isAssignableFrom(Object.class)) {
 657             // retyping can be done without a cast
 658             return FT_UNCHECKED_REF;
 659         } else {
 660             return ftype.isValue() ? FT_CHECKED_VALUE : FT_CHECKED_REF;
 661         }
 662     }
 663 
 664     /**
 665      * Create a LF which can access the given field.
 666      * Cache and share this structure among all fields with
 667      * the same basicType and refKind.
 668      */
 669     private static LambdaForm preparedFieldLambdaForm(MemberName m) {
 670         Class<?> ftype = m.getFieldType();

 671         byte formOp = switch (m.getReferenceKind()) {
 672             case REF_getField  -> AF_GETFIELD;
 673             case REF_putField  -> AF_PUTFIELD;
 674             case REF_getStatic -> AF_GETSTATIC;
 675             case REF_putStatic -> AF_PUTSTATIC;
 676             default -> throw new InternalError(m.toString());
 677         };
 678         if (shouldBeInitialized(m)) {
 679             // precompute the barrier-free version:
 680             preparedFieldLambdaForm(formOp, m.isVolatile(), m.isFlat(), m.isNullRestricted(), ftype);
 681             assert((AF_GETSTATIC_INIT - AF_GETSTATIC) ==
 682                    (AF_PUTSTATIC_INIT - AF_PUTSTATIC));
 683             formOp += (AF_GETSTATIC_INIT - AF_GETSTATIC);
 684         }
 685         LambdaForm lform = preparedFieldLambdaForm(formOp, m.isVolatile(), m.isFlat(), m.isNullRestricted(), ftype);
 686         maybeCompile(lform, m);
 687         assert(lform.methodType().dropParameterTypes(0, 1)
 688                 .equals(m.getInvocationType().basicType()))
 689                 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
 690         return lform;
 691     }
 692 
 693     private static LambdaForm preparedFieldLambdaForm(byte formOp, boolean isVolatile,
 694                                                       boolean isFlat, boolean isNullRestricted, Class<?> ftype) {
 695         int ftypeKind = ftypeKind(ftype);
 696         int afIndex = afIndex(formOp, isVolatile, isFlat, isNullRestricted, ftypeKind);
 697         LambdaForm lform = ACCESSOR_FORMS[afIndex];
 698         if (lform != null)  return lform;
 699         lform = makePreparedFieldLambdaForm(formOp, isVolatile,isFlat, isNullRestricted, ftypeKind);
 700         ACCESSOR_FORMS[afIndex] = lform;  // don't bother with a CAS
 701         return lform;
 702     }
 703 
 704     private static final Wrapper[] ALL_WRAPPERS = Wrapper.values();
 705 
 706     private static Kind getFieldKind(boolean isGetter, boolean isVolatile, boolean isFlat, Wrapper wrapper) {
 707         if (isGetter) {
 708             if (isVolatile) {
 709                 switch (wrapper) {
 710                     case BOOLEAN: return GET_BOOLEAN_VOLATILE;
 711                     case BYTE:    return GET_BYTE_VOLATILE;
 712                     case SHORT:   return GET_SHORT_VOLATILE;
 713                     case CHAR:    return GET_CHAR_VOLATILE;
 714                     case INT:     return GET_INT_VOLATILE;
 715                     case LONG:    return GET_LONG_VOLATILE;
 716                     case FLOAT:   return GET_FLOAT_VOLATILE;
 717                     case DOUBLE:  return GET_DOUBLE_VOLATILE;
 718                     case OBJECT:  return isFlat ? GET_VALUE_VOLATILE : GET_REFERENCE_VOLATILE;
 719                 }
 720             } else {
 721                 switch (wrapper) {
 722                     case BOOLEAN: return GET_BOOLEAN;
 723                     case BYTE:    return GET_BYTE;
 724                     case SHORT:   return GET_SHORT;
 725                     case CHAR:    return GET_CHAR;
 726                     case INT:     return GET_INT;
 727                     case LONG:    return GET_LONG;
 728                     case FLOAT:   return GET_FLOAT;
 729                     case DOUBLE:  return GET_DOUBLE;
 730                     case OBJECT:  return isFlat ? GET_VALUE : GET_REFERENCE;
 731                 }
 732             }
 733         } else {
 734             if (isVolatile) {
 735                 switch (wrapper) {
 736                     case BOOLEAN: return PUT_BOOLEAN_VOLATILE;
 737                     case BYTE:    return PUT_BYTE_VOLATILE;
 738                     case SHORT:   return PUT_SHORT_VOLATILE;
 739                     case CHAR:    return PUT_CHAR_VOLATILE;
 740                     case INT:     return PUT_INT_VOLATILE;
 741                     case LONG:    return PUT_LONG_VOLATILE;
 742                     case FLOAT:   return PUT_FLOAT_VOLATILE;
 743                     case DOUBLE:  return PUT_DOUBLE_VOLATILE;
 744                     case OBJECT:  return isFlat ? PUT_VALUE_VOLATILE : PUT_REFERENCE_VOLATILE;
 745                 }
 746             } else {
 747                 switch (wrapper) {
 748                     case BOOLEAN: return PUT_BOOLEAN;
 749                     case BYTE:    return PUT_BYTE;
 750                     case SHORT:   return PUT_SHORT;
 751                     case CHAR:    return PUT_CHAR;
 752                     case INT:     return PUT_INT;
 753                     case LONG:    return PUT_LONG;
 754                     case FLOAT:   return PUT_FLOAT;
 755                     case DOUBLE:  return PUT_DOUBLE;
 756                     case OBJECT:  return isFlat ? PUT_VALUE : PUT_REFERENCE;
 757                 }
 758             }
 759         }
 760         throw new AssertionError("Invalid arguments");
 761     }
 762 
 763     /** invoked by GenerateJLIClassesHelper */
 764     static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, int ftype) {
 765         return makePreparedFieldLambdaForm(formOp, isVolatile, false, false, ftype);
 766     }
 767 
 768     private static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile,
 769                                                           boolean isFlat, boolean isNullRestricted, int ftypeKind) {
 770         boolean isGetter  = (formOp & 1) == (AF_GETFIELD & 1);
 771         boolean isStatic  = (formOp >= AF_GETSTATIC);
 772         boolean needsInit = (formOp >= AF_GETSTATIC_INIT);
 773         boolean needsCast = (ftypeKind == FT_CHECKED_REF || ftypeKind == FT_CHECKED_VALUE);
 774         Wrapper fw = (needsCast ? Wrapper.OBJECT : ALL_WRAPPERS[ftypeKind]);
 775         Class<?> ft = fw.primitiveType();
 776         assert(needsCast ? true : ftypeKind(ft) == ftypeKind);
 777 
 778         // getObject, putIntVolatile, etc.
 779         Kind kind = getFieldKind(isGetter, isVolatile, isFlat, fw);
 780 
 781         MethodType linkerType;
 782         if (isGetter) {
 783             linkerType = isFlat
 784                             ? MethodType.methodType(ft, Object.class, long.class, Class.class)
 785                             : MethodType.methodType(ft, Object.class, long.class);
 786         } else {
 787             linkerType = isFlat
 788                             ? MethodType.methodType(void.class, Object.class, long.class, Class.class, ft)
 789                             : MethodType.methodType(void.class, Object.class, long.class, ft);
 790         }
 791         MemberName linker = new MemberName(Unsafe.class, kind.methodName, linkerType, REF_invokeVirtual);
 792         try {
 793             linker = IMPL_NAMES.resolveOrFail(REF_invokeVirtual, linker, null, LM_TRUSTED,
 794                                               NoSuchMethodException.class);
 795         } catch (ReflectiveOperationException ex) {
 796             throw newInternalError(ex);
 797         }
 798 
 799         // What is the external type of the lambda form?
 800         MethodType mtype;
 801         if (isGetter)
 802             mtype = MethodType.methodType(ft);
 803         else
 804             mtype = MethodType.methodType(void.class, ft);
 805         mtype = mtype.basicType();  // erase short to int, etc.
 806         if (!isStatic)
 807             mtype = mtype.insertParameterTypes(0, Object.class);
 808         final int DMH_THIS  = 0;
 809         final int ARG_BASE  = 1;
 810         final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
 811         // if this is for non-static access, the base pointer is stored at this index:
 812         final int OBJ_BASE  = isStatic ? -1 : ARG_BASE;
 813         // if this is for write access, the value to be written is stored at this index:
 814         final int SET_VALUE  = isGetter ? -1 : ARG_LIMIT - 1;
 815         int nameCursor = ARG_LIMIT;
 816         final int F_HOLDER  = (isStatic ? nameCursor++ : -1);  // static base if any
 817         final int F_OFFSET  = nameCursor++;  // Either static offset or field offset.
 818         final int OBJ_CHECK = (OBJ_BASE >= 0 ? nameCursor++ : -1);
 819         final int U_HOLDER  = nameCursor++;  // UNSAFE holder
 820         final int INIT_BAR  = (needsInit ? nameCursor++ : -1);
 821         final int VALUE_TYPE = (isFlat ? nameCursor++ : -1);
 822         final int NULL_CHECK  = (isNullRestricted && !isGetter ? nameCursor++ : -1);
 823         final int PRE_CAST  = (needsCast && !isGetter ? nameCursor++ : -1);
 824         final int LINKER_CALL = nameCursor++;
 825         final int FIELD_TYPE = (isNullRestricted && isGetter ? nameCursor++ : -1);
 826         final int ZERO_INSTANCE = (isNullRestricted && isGetter ? nameCursor++ : -1);
 827         final int POST_CAST = (needsCast && isGetter ? nameCursor++ : -1);
 828         final int RESULT    = nameCursor-1;  // either the call, zero instance, or the cast
 829         Name[] names = invokeArguments(nameCursor - ARG_LIMIT, mtype);
 830         if (needsInit)
 831             names[INIT_BAR] = new Name(getFunction(NF_ensureInitialized), names[DMH_THIS]);
 832         if (!isGetter) {
 833             if (isNullRestricted)
 834                 names[NULL_CHECK] = new Name(getFunction(NF_nullCheck), names[SET_VALUE]);
 835             if (needsCast)
 836                 names[PRE_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[SET_VALUE]);
 837         }
 838         Object[] outArgs = new Object[1 + linkerType.parameterCount()];
 839         assert (outArgs.length == (isGetter ? 3 : 4) + (isFlat ? 1 : 0));
 840         outArgs[0] = names[U_HOLDER] = new Name(getFunction(NF_UNSAFE));
 841         if (isStatic) {
 842             outArgs[1] = names[F_HOLDER]  = new Name(getFunction(NF_staticBase), names[DMH_THIS]);
 843             outArgs[2] = names[F_OFFSET]  = new Name(getFunction(NF_staticOffset), names[DMH_THIS]);
 844         } else {
 845             outArgs[1] = names[OBJ_CHECK] = new Name(getFunction(NF_checkBase), names[OBJ_BASE]);
 846             outArgs[2] = names[F_OFFSET]  = new Name(getFunction(NF_fieldOffset), names[DMH_THIS]);
 847         }
 848         int x = 3;
 849         if (isFlat) {
 850             outArgs[x++] = names[VALUE_TYPE] = isStatic ? new Name(getFunction(NF_staticFieldType), names[DMH_THIS])
 851                                                         : new Name(getFunction(NF_fieldType), names[DMH_THIS]);
 852         }
 853         if (!isGetter) {
 854             outArgs[x] = (needsCast ? names[PRE_CAST] : names[SET_VALUE]);
 855         }
 856         for (Object a : outArgs)  assert(a != null);
 857         names[LINKER_CALL] = new Name(linker, outArgs);
 858         if (isGetter) {
 859             int argIndex = LINKER_CALL;
 860             if (isNullRestricted) {
 861                 names[FIELD_TYPE] = isStatic ? new Name(getFunction(NF_staticFieldType), names[DMH_THIS])
 862                                              : new Name(getFunction(NF_fieldType), names[DMH_THIS]);
 863                 names[ZERO_INSTANCE] = new Name(getFunction(NF_zeroInstance), names[FIELD_TYPE], names[LINKER_CALL]);
 864                 argIndex = ZERO_INSTANCE;
 865             }
 866             if (needsCast)
 867                 names[POST_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[argIndex]);
 868         }
 869         for (Name n : names)  assert(n != null);
 870 
 871         LambdaForm form;
 872         if (needsCast || needsInit) {
 873             // can't use the pre-generated form when casting and/or initializing
 874             form = LambdaForm.create(ARG_LIMIT, names, RESULT);
 875         } else {
 876             form = LambdaForm.create(ARG_LIMIT, names, RESULT, kind);
 877         }
 878 
 879         if (LambdaForm.debugNames()) {
 880             // add some detail to the lambdaForm debugname,
 881             // significant only for debugging
 882             StringBuilder nameBuilder = new StringBuilder(kind.methodName);
 883             if (isStatic) {
 884                 nameBuilder.append("Static");
 885             } else {
 886                 nameBuilder.append("Field");
 887             }
 888             if (needsCast) {

 894             LambdaForm.associateWithDebugName(form, nameBuilder.toString());
 895         }
 896         return form;
 897     }
 898 
 899     /**
 900      * Pre-initialized NamedFunctions for bootstrapping purposes.
 901      */
 902     static final byte NF_internalMemberName = 0,
 903             NF_internalMemberNameEnsureInit = 1,
 904             NF_ensureInitialized = 2,
 905             NF_fieldOffset = 3,
 906             NF_checkBase = 4,
 907             NF_staticBase = 5,
 908             NF_staticOffset = 6,
 909             NF_checkCast = 7,
 910             NF_allocateInstance = 8,
 911             NF_constructorMethod = 9,
 912             NF_UNSAFE = 10,
 913             NF_checkReceiver = 11,
 914             NF_fieldType = 12,
 915             NF_staticFieldType = 13,
 916             NF_zeroInstance = 14,
 917             NF_nullCheck = 15,
 918             NF_LIMIT = 16;
 919 
 920     private static final @Stable NamedFunction[] NFS = new NamedFunction[NF_LIMIT];
 921 
 922     private static NamedFunction getFunction(byte func) {
 923         NamedFunction nf = NFS[func];
 924         if (nf != null) {
 925             return nf;
 926         }
 927         // Each nf must be statically invocable or we get tied up in our bootstraps.
 928         nf = NFS[func] = createFunction(func);
 929         assert(InvokerBytecodeGenerator.isStaticallyInvocable(nf));
 930         return nf;
 931     }
 932 
 933     private static final MethodType CLS_OBJ_TYPE = MethodType.methodType(Class.class, Object.class);
 934 
 935     private static final MethodType OBJ_OBJ_TYPE = MethodType.methodType(Object.class, Object.class);
 936 
 937     private static final MethodType LONG_OBJ_TYPE = MethodType.methodType(long.class, Object.class);
 938 
 939     private static NamedFunction createFunction(byte func) {
 940         try {
 941             switch (func) {
 942                 case NF_internalMemberName:
 943                     return getNamedFunction("internalMemberName", OBJ_OBJ_TYPE);
 944                 case NF_internalMemberNameEnsureInit:
 945                     return getNamedFunction("internalMemberNameEnsureInit", OBJ_OBJ_TYPE);
 946                 case NF_ensureInitialized:
 947                     return getNamedFunction("ensureInitialized", MethodType.methodType(void.class, Object.class));
 948                 case NF_fieldOffset:
 949                     return getNamedFunction("fieldOffset", LONG_OBJ_TYPE);
 950                 case NF_checkBase:
 951                     return getNamedFunction("checkBase", OBJ_OBJ_TYPE);
 952                 case NF_staticBase:
 953                     return getNamedFunction("staticBase", OBJ_OBJ_TYPE);
 954                 case NF_staticOffset:
 955                     return getNamedFunction("staticOffset", LONG_OBJ_TYPE);
 956                 case NF_checkCast:
 957                     return getNamedFunction("checkCast", MethodType.methodType(Object.class, Object.class, Object.class));
 958                 case NF_allocateInstance:
 959                     return getNamedFunction("allocateInstance", OBJ_OBJ_TYPE);
 960                 case NF_constructorMethod:
 961                     return getNamedFunction("constructorMethod", OBJ_OBJ_TYPE);
 962                 case NF_UNSAFE:
 963                     MemberName member = new MemberName(MethodHandleStatics.class, "UNSAFE", Unsafe.class, REF_getStatic);
 964                     return new NamedFunction(
 965                             MemberName.getFactory().resolveOrFail(REF_getStatic, member,
 966                                                                   DirectMethodHandle.class, LM_TRUSTED,
 967                                                                   NoSuchFieldException.class));
 968                 case NF_checkReceiver:
 969                     member = new MemberName(DirectMethodHandle.class, "checkReceiver", OBJ_OBJ_TYPE, REF_invokeVirtual);
 970                     return new NamedFunction(
 971                             MemberName.getFactory().resolveOrFail(REF_invokeVirtual, member,
 972                                                                   DirectMethodHandle.class, LM_TRUSTED,
 973                                                                   NoSuchMethodException.class));
 974                 case NF_fieldType:
 975                     return getNamedFunction("fieldType", CLS_OBJ_TYPE);
 976                 case NF_staticFieldType:
 977                     return getNamedFunction("staticFieldType", CLS_OBJ_TYPE);
 978                 case NF_zeroInstance:
 979                     return getNamedFunction("zeroInstanceIfNull", MethodType.methodType(Object.class, Class.class, Object.class));
 980                 case NF_nullCheck:
 981                     return getNamedFunction("nullCheck", OBJ_OBJ_TYPE);
 982                 default:
 983                     throw newInternalError("Unknown function: " + func);
 984             }
 985         } catch (ReflectiveOperationException ex) {
 986             throw newInternalError(ex);
 987         }
 988     }
 989 
 990     private static NamedFunction getNamedFunction(String name, MethodType type)
 991         throws ReflectiveOperationException
 992     {
 993         MemberName member = new MemberName(DirectMethodHandle.class, name, type, REF_invokeStatic);
 994         return new NamedFunction(
 995                 MemberName.getFactory().resolveOrFail(REF_invokeStatic, member,
 996                                                       DirectMethodHandle.class, LM_TRUSTED,
 997                                                       NoSuchMethodException.class));
 998     }
 999 
1000     static {
1001         // The Holder class will contain pre-generated DirectMethodHandles resolved
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