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src/java.base/share/classes/java/lang/runtime/SwitchBootstraps.java

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726               .with(StackMapTableAttribute.of(stackMapFrames));
727             DirectCodeBuilder.withMaxs(cb, 3, locals.size()); // enum labels use 3 stack, others use 2
728         };
729     }
730 
731     private static boolean isNotValidPair(Class<?> selectorType, Object caseLabel) {
732         return (selectorType == boolean.class && caseLabel != boolean.class && caseLabel != Boolean.class) ||
733                (selectorType != boolean.class && selectorType.isPrimitive() && (caseLabel == boolean.class || caseLabel == Boolean.class));
734     }
735 
736     /*
737      * Construct the method handle that represents the method int typeSwitch(Object, int, BiPredicate, List)
738      */
739     private static MethodHandle generateTypeSwitch(MethodHandles.Lookup caller, Class<?> selectorType, Object[] labelConstants) {
740         boolean addExtraInfo = needsExtraInfo(selectorType, labelConstants);
741         List<EnumDesc<?>> enumDescs = addExtraInfo ? new ArrayList<>() : null;
742         List<Class<?>> extraClassLabels = addExtraInfo ? new ArrayList<>() : null;
743 
744         byte[] classBytes = ClassFile.of(ClassFile.StackMapsOption.DROP_STACK_MAPS).build(ConstantUtils.binaryNameToDesc(typeSwitchClassName(caller.lookupClass())),
745                 clb -> {
746                     clb.withFlags(AccessFlag.FINAL, AccessFlag.SUPER, AccessFlag.SYNTHETIC)
747                        .withMethodBody("typeSwitch",
748                                        addExtraInfo ? MTD_TYPE_SWITCH_EXTRA : MTD_TYPE_SWITCH,
749                                        ClassFile.ACC_FINAL | ClassFile.ACC_PUBLIC | ClassFile.ACC_STATIC,
750                                        generateTypeSwitchSkeleton(selectorType, labelConstants, enumDescs, extraClassLabels));
751         });
752 
753         try {
754             // this class is linked at the indy callsite; so define a hidden nestmate
755             MethodHandles.Lookup lookup;
756             lookup = caller.defineHiddenClass(classBytes, true, NESTMATE, STRONG);
757             MethodHandle typeSwitch = lookup.findStatic(lookup.lookupClass(),
758                                                         "typeSwitch",
759                                                         addExtraInfo ? MT_TYPE_SWITCH_EXTRA : MT_TYPE_SWITCH);
760             if (addExtraInfo) {
761                 typeSwitch = MethodHandles.insertArguments(typeSwitch, 2, new ResolvedEnumLabels(caller, enumDescs.toArray(new EnumDesc<?>[0])),
762                         List.copyOf(extraClassLabels));
763             }
764             return typeSwitch;
765         } catch (Throwable t) {
766             throw new IllegalArgumentException(t);

726               .with(StackMapTableAttribute.of(stackMapFrames));
727             DirectCodeBuilder.withMaxs(cb, 3, locals.size()); // enum labels use 3 stack, others use 2
728         };
729     }
730 
731     private static boolean isNotValidPair(Class<?> selectorType, Object caseLabel) {
732         return (selectorType == boolean.class && caseLabel != boolean.class && caseLabel != Boolean.class) ||
733                (selectorType != boolean.class && selectorType.isPrimitive() && (caseLabel == boolean.class || caseLabel == Boolean.class));
734     }
735 
736     /*
737      * Construct the method handle that represents the method int typeSwitch(Object, int, BiPredicate, List)
738      */
739     private static MethodHandle generateTypeSwitch(MethodHandles.Lookup caller, Class<?> selectorType, Object[] labelConstants) {
740         boolean addExtraInfo = needsExtraInfo(selectorType, labelConstants);
741         List<EnumDesc<?>> enumDescs = addExtraInfo ? new ArrayList<>() : null;
742         List<Class<?>> extraClassLabels = addExtraInfo ? new ArrayList<>() : null;
743 
744         byte[] classBytes = ClassFile.of(ClassFile.StackMapsOption.DROP_STACK_MAPS).build(ConstantUtils.binaryNameToDesc(typeSwitchClassName(caller.lookupClass())),
745                 clb -> {
746                     clb.withFlags(AccessFlag.FINAL, (PreviewFeatures.isEnabled())  ? AccessFlag.IDENTITY : AccessFlag.SUPER, AccessFlag.SYNTHETIC)
747                        .withMethodBody("typeSwitch",
748                                        addExtraInfo ? MTD_TYPE_SWITCH_EXTRA : MTD_TYPE_SWITCH,
749                                        ClassFile.ACC_FINAL | ClassFile.ACC_PUBLIC | ClassFile.ACC_STATIC,
750                                        generateTypeSwitchSkeleton(selectorType, labelConstants, enumDescs, extraClassLabels));
751         });
752 
753         try {
754             // this class is linked at the indy callsite; so define a hidden nestmate
755             MethodHandles.Lookup lookup;
756             lookup = caller.defineHiddenClass(classBytes, true, NESTMATE, STRONG);
757             MethodHandle typeSwitch = lookup.findStatic(lookup.lookupClass(),
758                                                         "typeSwitch",
759                                                         addExtraInfo ? MT_TYPE_SWITCH_EXTRA : MT_TYPE_SWITCH);
760             if (addExtraInfo) {
761                 typeSwitch = MethodHandles.insertArguments(typeSwitch, 2, new ResolvedEnumLabels(caller, enumDescs.toArray(new EnumDesc<?>[0])),
762                         List.copyOf(extraClassLabels));
763             }
764             return typeSwitch;
765         } catch (Throwable t) {
766             throw new IllegalArgumentException(t);
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