1 /*
2 * Copyright (c) 2017, 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang.runtime;
27
28 import java.lang.Enum.EnumDesc;
29 import java.lang.classfile.CodeBuilder;
30 import java.lang.constant.ClassDesc;
31 import java.lang.constant.ConstantDesc;
32 import java.lang.constant.MethodTypeDesc;
33 import java.lang.invoke.CallSite;
34 import java.lang.invoke.ConstantCallSite;
35 import java.lang.invoke.MethodHandle;
36 import java.lang.invoke.MethodHandles;
37 import java.lang.invoke.MethodType;
38 import java.lang.reflect.AccessFlag;
39 import java.util.ArrayList;
40 import java.util.List;
41 import java.util.Objects;
42 import java.util.Optional;
43 import java.util.function.BiPredicate;
44 import java.util.function.Consumer;
45
46 import jdk.internal.access.SharedSecrets;
47 import java.lang.classfile.ClassFile;
48 import java.lang.classfile.Label;
49 import java.lang.classfile.instruction.SwitchCase;
50
51 import jdk.internal.constant.MethodTypeDescImpl;
52 import jdk.internal.constant.ReferenceClassDescImpl;
53 import jdk.internal.constant.ConstantUtils;
54 import jdk.internal.misc.PreviewFeatures;
55 import jdk.internal.vm.annotation.Stable;
56
57 import static java.lang.constant.ConstantDescs.*;
58 import static java.lang.invoke.MethodHandles.Lookup.ClassOption.NESTMATE;
59 import static java.lang.invoke.MethodHandles.Lookup.ClassOption.STRONG;
60 import java.util.Arrays;
61 import java.util.HashMap;
62 import java.util.Map;
63 import static java.util.Objects.requireNonNull;
64 import static jdk.internal.constant.ConstantUtils.classDesc;
65 import static jdk.internal.constant.ConstantUtils.referenceClassDesc;
66
67 import sun.invoke.util.Wrapper;
68
69 /**
70 * Bootstrap methods for linking {@code invokedynamic} call sites that implement
71 * the selection functionality of the {@code switch} statement. The bootstraps
72 * take additional static arguments corresponding to the {@code case} labels
73 * of the {@code switch}, implicitly numbered sequentially from {@code [0..N)}.
74 *
75 * @since 21
76 */
77 public class SwitchBootstraps {
78
79 private SwitchBootstraps() {}
80
81 private static final Object SENTINEL = new Object();
82 private static final MethodHandles.Lookup LOOKUP = MethodHandles.lookup();
83 private static final boolean previewEnabled = PreviewFeatures.isEnabled();
84
85 private static final ClassDesc CD_BiPredicate = ReferenceClassDescImpl.ofValidated("Ljava/util/function/BiPredicate;");
86 private static final ClassDesc CD_Objects = ReferenceClassDescImpl.ofValidated("Ljava/util/Objects;");
87
88 private static final MethodTypeDesc CHECK_INDEX_DESCRIPTOR =
89 MethodTypeDescImpl.ofValidated(CD_int, CD_int, CD_int);
90 private static final MethodTypeDesc MTD_TYPE_SWITCH = MethodTypeDescImpl.ofValidated(CD_int,
91 CD_Object,
92 CD_int);
93 private static final MethodTypeDesc MTD_TYPE_SWITCH_EXTRA = MethodTypeDescImpl.ofValidated(CD_int,
94 CD_Object,
95 CD_int,
96 CD_BiPredicate,
97 CD_List);
98 private static final MethodType MT_TYPE_SWITCH_EXTRA = MethodType.methodType(int.class,
99 Object.class,
100 int.class,
101 BiPredicate.class,
102 List.class);
103 private static final MethodType MT_TYPE_SWITCH = MethodType.methodType(int.class,
104 Object.class,
105 int.class);
106
107 private static class StaticHolders {
108 private static final MethodHandle MAPPED_ENUM_SWITCH;
109
110 static {
111 try {
112 MAPPED_ENUM_SWITCH = LOOKUP.findStatic(SwitchBootstraps.class, "mappedEnumSwitch",
113 MethodType.methodType(int.class, Enum.class, int.class, MethodHandles.Lookup.class,
114 Class.class, EnumDesc[].class, MappedEnumCache.class));
115 }
116 catch (ReflectiveOperationException e) {
117 throw new ExceptionInInitializerError(e);
118 }
119 }
120 }
121
122 /**
123 * Bootstrap method for linking an {@code invokedynamic} call site that
124 * implements a {@code switch} on a target of a reference type. The static
125 * arguments are an array of case labels which must be non-null and of type
126 * {@code String} or {@code Integer} or {@code Class} or {@code EnumDesc}.
127 * <p>
128 * The type of the returned {@code CallSite}'s method handle will have
129 * a return type of {@code int}. It has two parameters: the first argument
130 * will be an {@code Object} instance ({@code target}) and the second
131 * will be {@code int} ({@code restart}).
132 * <p>
133 * If the {@code target} is {@code null}, then the method of the call site
134 * returns {@literal -1}.
135 * <p>
136 * If the {@code target} is not {@code null}, then the method of the call site
137 * returns the index of the first element in the {@code labels} array starting from
138 * the {@code restart} index matching one of the following conditions:
139 * <ul>
140 * <li>the element is of type {@code Class} that is assignable
141 * from the target's class; or</li>
142 * <li>the element is of type {@code String} or {@code Integer} and
143 * equals to the target.</li>
144 * <li>the element is of type {@code EnumDesc}, that describes a constant that is
145 * equals to the target.</li>
146 * </ul>
147 * <p>
148 * If no element in the {@code labels} array matches the target, then
149 * the method of the call site return the length of the {@code labels} array.
150 * <p>
151 * The value of the {@code restart} index must be between {@code 0} (inclusive) and
152 * the length of the {@code labels} array (inclusive),
153 * both or an {@link IndexOutOfBoundsException} is thrown.
154 *
155 * @param lookup Represents a lookup context with the accessibility
156 * privileges of the caller. When used with {@code invokedynamic},
157 * this is stacked automatically by the VM.
158 * @param invocationName unused
159 * @param invocationType The invocation type of the {@code CallSite} with two parameters,
160 * a reference type, an {@code int}, and {@code int} as a return type.
161 * @param labels case labels - {@code String} and {@code Integer} constants
162 * and {@code Class} and {@code EnumDesc} instances, in any combination
163 * @return a {@code CallSite} returning the first matching element as described above
164 *
165 * @throws NullPointerException if any argument is {@code null}
166 * @throws IllegalArgumentException if any element in the labels array is null
167 * @throws IllegalArgumentException if the invocation type is not a method type of first parameter of a reference type,
168 * second parameter of type {@code int} and with {@code int} as its return type,
169 * @throws IllegalArgumentException if {@code labels} contains an element that is not of type {@code String},
170 * {@code Integer}, {@code Long}, {@code Float}, {@code Double}, {@code Boolean},
171 * {@code Class} or {@code EnumDesc}.
172 * @throws IllegalArgumentException if {@code labels} contains an element that is not of type {@code Boolean}
173 * when {@code target} is a {@code Boolean.class}.
174 * @jvms 4.4.6 The CONSTANT_NameAndType_info Structure
175 * @jvms 4.4.10 The CONSTANT_Dynamic_info and CONSTANT_InvokeDynamic_info Structures
176 */
177 public static CallSite typeSwitch(MethodHandles.Lookup lookup,
178 String invocationName,
179 MethodType invocationType,
180 Object... labels) {
181 Class<?> selectorType = invocationType.parameterType(0);
182 if (invocationType.parameterCount() != 2
183 || (!invocationType.returnType().equals(int.class))
184 || !invocationType.parameterType(1).equals(int.class))
185 throw new IllegalArgumentException("Illegal invocation type " + invocationType);
186
187 for (Object l : labels) { // implicit null-check
188 verifyLabel(l, selectorType);
189 }
190
191 MethodHandle target = generateTypeSwitch(lookup, selectorType, labels);
192 target = target.asType(invocationType);
193 return new ConstantCallSite(target);
194 }
195
196 private static void verifyLabel(Object label, Class<?> selectorType) {
197 if (label == null) {
198 throw new IllegalArgumentException("null label found");
199 }
200 Class<?> labelClass = label.getClass();
201
202 if (labelClass != Class.class &&
203 labelClass != String.class &&
204 labelClass != Integer.class &&
205
206 ((labelClass != Float.class &&
207 labelClass != Long.class &&
208 labelClass != Double.class &&
209 labelClass != Boolean.class) ||
210 ((selectorType.equals(boolean.class) || selectorType.equals(Boolean.class)) && labelClass != Boolean.class && labelClass != Class.class) ||
211 !previewEnabled) &&
212
213 labelClass != EnumDesc.class) {
214 throw new IllegalArgumentException("label with illegal type found: " + label.getClass());
215 }
216 }
217
218 /**
219 * Bootstrap method for linking an {@code invokedynamic} call site that
220 * implements a {@code switch} on a target of an enum type. The static
221 * arguments are used to encode the case labels associated to the switch
222 * construct, where each label can be encoded in two ways:
223 * <ul>
224 * <li>as a {@code String} value, which represents the name of
225 * the enum constant associated with the label</li>
226 * <li>as a {@code Class} value, which represents the enum type
227 * associated with a type test pattern</li>
228 * </ul>
229 * <p>
230 * The returned {@code CallSite}'s method handle will have
231 * a return type of {@code int} and accepts two parameters: the first argument
232 * will be an {@code Enum} instance ({@code target}) and the second
233 * will be {@code int} ({@code restart}).
234 * <p>
235 * If the {@code target} is {@code null}, then the method of the call site
236 * returns {@literal -1}.
237 * <p>
238 * If the {@code target} is not {@code null}, then the method of the call site
239 * returns the index of the first element in the {@code labels} array starting from
240 * the {@code restart} index matching one of the following conditions:
241 * <ul>
242 * <li>the element is of type {@code Class} that is assignable
243 * from the target's class; or</li>
244 * <li>the element is of type {@code String} and equals to the target
245 * enum constant's {@link Enum#name()}.</li>
246 * </ul>
247 * <p>
248 * If no element in the {@code labels} array matches the target, then
249 * the method of the call site return the length of the {@code labels} array.
250 * <p>
251 * The value of the {@code restart} index must be between {@code 0} (inclusive) and
252 * the length of the {@code labels} array (inclusive),
253 * both or an {@link IndexOutOfBoundsException} is thrown.
254 *
255 * @param lookup Represents a lookup context with the accessibility
256 * privileges of the caller. When used with {@code invokedynamic},
257 * this is stacked automatically by the VM.
258 * @param invocationName unused
259 * @param invocationType The invocation type of the {@code CallSite} with two parameters,
260 * an enum type, an {@code int}, and {@code int} as a return type.
261 * @param labels case labels - {@code String} constants and {@code Class} instances,
262 * in any combination
263 * @return a {@code CallSite} returning the first matching element as described above
264 *
265 * @throws NullPointerException if any argument is {@code null}
266 * @throws IllegalArgumentException if any element in the labels array is null, if the
267 * invocation type is not a method type whose first parameter type is an enum type,
268 * second parameter of type {@code int} and whose return type is {@code int},
269 * or if {@code labels} contains an element that is not of type {@code String} or
270 * {@code Class} of the target enum type.
271 * @jvms 4.4.6 The CONSTANT_NameAndType_info Structure
272 * @jvms 4.4.10 The CONSTANT_Dynamic_info and CONSTANT_InvokeDynamic_info Structures
273 */
274 public static CallSite enumSwitch(MethodHandles.Lookup lookup,
275 String invocationName,
276 MethodType invocationType,
277 Object... labels) {
278 if (invocationType.parameterCount() != 2
279 || (!invocationType.returnType().equals(int.class))
280 || invocationType.parameterType(0).isPrimitive()
281 || !invocationType.parameterType(0).isEnum()
282 || !invocationType.parameterType(1).equals(int.class))
283 throw new IllegalArgumentException("Illegal invocation type " + invocationType);
284
285 labels = labels.clone(); // implicit null check
286
287 Class<?> enumClass = invocationType.parameterType(0);
288 boolean constantsOnly = true;
289 int len = labels.length;
290
291 for (int i = 0; i < len; i++) {
292 Object convertedLabel =
293 convertEnumConstants(lookup, enumClass, labels[i]);
294 labels[i] = convertedLabel;
295 if (constantsOnly)
296 constantsOnly = convertedLabel instanceof EnumDesc;
297 }
298
299 MethodHandle target;
300
301 if (labels.length > 0 && constantsOnly) {
302 //If all labels are enum constants, construct an optimized handle for repeat index 0:
303 //if (selector == null) return -1
304 //else if (idx == 0) return mappingArray[selector.ordinal()]; //mapping array created lazily
305 //else return "typeSwitch(labels)"
306 EnumDesc<?>[] enumDescLabels =
307 Arrays.copyOf(labels, labels.length, EnumDesc[].class);
308 target = MethodHandles.insertArguments(StaticHolders.MAPPED_ENUM_SWITCH, 2, lookup, enumClass, enumDescLabels, new MappedEnumCache());
309 } else {
310 target = generateTypeSwitch(lookup, invocationType.parameterType(0), labels);
311 }
312 target = target.asType(invocationType);
313
314 return new ConstantCallSite(target);
315 }
316
317 private static <E extends Enum<E>> Object convertEnumConstants(MethodHandles.Lookup lookup, Class<?> enumClassTemplate, Object label) {
318 if (label == null) {
319 throw new IllegalArgumentException("null label found");
320 }
321 Class<?> labelClass = label.getClass();
322 if (labelClass == Class.class) {
323 if (label != enumClassTemplate) {
324 throw new IllegalArgumentException("the Class label: " + label +
325 ", expected the provided enum class: " + enumClassTemplate);
326 }
327 return label;
328 } else if (labelClass == String.class) {
329 return EnumDesc.of(referenceClassDesc(enumClassTemplate), (String) label);
330 } else {
331 throw new IllegalArgumentException("label with illegal type found: " + labelClass +
332 ", expected label of type either String or Class");
333 }
334 }
335
336 private static <T extends Enum<T>> int mappedEnumSwitch(T value, int restartIndex, MethodHandles.Lookup lookup, Class<T> enumClass, EnumDesc<?>[] labels, MappedEnumCache enumCache) throws Throwable {
337 if (value == null) {
338 return -1;
339 }
340
341 if (restartIndex != 0) {
342 MethodHandle generatedSwitch = enumCache.generatedSwitch;
343 if (generatedSwitch == null) {
344 synchronized (enumCache) {
345 generatedSwitch = enumCache.generatedSwitch;
346
347 if (generatedSwitch == null) {
348 generatedSwitch =
349 generateTypeSwitch(lookup, enumClass, labels)
350 .asType(MethodType.methodType(int.class,
351 Enum.class,
352 int.class));
353 enumCache.generatedSwitch = generatedSwitch;
354 }
355 }
356 }
357
358 return (int) generatedSwitch.invokeExact(value, restartIndex);
359 }
360
361 int[] constantsMap = enumCache.constantsMap;
362
363 if (constantsMap == null) {
364 synchronized (enumCache) {
365 constantsMap = enumCache.constantsMap;
366
367 if (constantsMap == null) {
368 T[] constants = SharedSecrets.getJavaLangAccess()
369 .getEnumConstantsShared(enumClass);
370 constantsMap = new int[constants.length];
371 int ordinal = 0;
372
373 for (T constant : constants) {
374 constantsMap[ordinal] = labels.length;
375
376 for (int i = 0; i < labels.length; i++) {
377 if (Objects.equals(labels[i].constantName(),
378 constant.name())) {
379 constantsMap[ordinal] = i;
380 break;
381 }
382 }
383
384 ordinal++;
385 }
386
387 enumCache.constantsMap = constantsMap;
388 }
389 }
390 }
391
392 return constantsMap[value.ordinal()];
393 }
394
395 private static final class ResolvedEnumLabels implements BiPredicate<Integer, Object> {
396
397 private final MethodHandles.Lookup lookup;
398 private final EnumDesc<?>[] enumDescs;
399 @Stable
400 private final Object[] resolvedEnum;
401
402 public ResolvedEnumLabels(MethodHandles.Lookup lookup, EnumDesc<?>[] enumDescs) {
403 this.lookup = lookup;
404 this.enumDescs = enumDescs;
405 this.resolvedEnum = new Object[enumDescs.length];
406 }
407
408 @Override
409 public boolean test(Integer labelIndex, Object value) {
410 Object result = resolvedEnum[labelIndex];
411
412 if (result == null) {
413 try {
414 if (!(value instanceof Enum<?> enumValue)) {
415 return false;
416 }
417
418 EnumDesc<?> label = enumDescs[labelIndex];
419 Class<?> clazz = label.constantType().resolveConstantDesc(lookup);
420
421 if (enumValue.getDeclaringClass() != clazz) {
422 return false;
423 }
424
425 result = label.resolveConstantDesc(lookup);
426 } catch (IllegalArgumentException | ReflectiveOperationException ex) {
427 result = SENTINEL;
428 }
429
430 resolvedEnum[labelIndex] = result;
431 }
432
433 return result == value;
434 }
435 }
436
437 private static final class MappedEnumCache {
438 @Stable
439 public int[] constantsMap;
440 @Stable
441 public MethodHandle generatedSwitch;
442 }
443
444 /**
445 * Check if the labelConstants can be converted statically to bytecode, or
446 * whether we'll need to compute and pass in extra information at the call site.
447 */
448 private static boolean needsExtraInfo(Class<?> selectorType, Object[] labelConstants) {
449 for (int idx = labelConstants.length - 1; idx >= 0; idx--) {
450 Object currentLabel = labelConstants[idx];
451 if (currentLabel instanceof Class<?> classLabel) {
452 // No extra info needed for exact matches or primitives
453 if (unconditionalExactnessCheck(selectorType, classLabel) || classLabel.isPrimitive()) {
454 continue;
455 }
456 // Hidden classes - or arrays thereof - can't be nominally
457 // represented. Passed in as arguments.
458 while (classLabel.isArray()) {
459 classLabel = classLabel.getComponentType();
460 }
461 if (classLabel.isHidden()) {
462 return true;
463 }
464 } else if (currentLabel instanceof EnumDesc<?>) {
465 // EnumDescs labels needs late binding
466 return true;
467 }
468 }
469 return false;
470 }
471 /*
472 * Construct test chains for labels inside switch, to handle switch repeats:
473 * switch (idx) {
474 * case 0 -> if (selector matches label[0]) return 0;
475 * case 1 -> if (selector matches label[1]) return 1;
476 * ...
477 * }
478 */
479 private static Consumer<CodeBuilder> generateTypeSwitchSkeleton(Class<?> selectorType, Object[] labelConstants, List<EnumDesc<?>> enumDescs, List<Class<?>> extraClassLabels) {
480 int SELECTOR_OBJ = 0;
481 int RESTART_IDX = 1;
482 int ENUM_CACHE = 2;
483 int EXTRA_CLASS_LABELS = 3;
484
485 return cb -> {
486 // Objects.checkIndex(RESTART_IDX, labelConstants + 1)
487 cb.iload(RESTART_IDX)
488 .loadConstant(labelConstants.length + 1)
489 .invokestatic(CD_Objects, "checkIndex", CHECK_INDEX_DESCRIPTOR)
490 .pop()
491 .aload(SELECTOR_OBJ);
492 Label nonNullLabel = cb.newLabel();
493 cb.ifnonnull(nonNullLabel)
494 .iconst_m1()
495 .ireturn()
496 .labelBinding(nonNullLabel);
497 if (labelConstants.length == 0) {
498 cb.loadConstant(0)
499 .ireturn();
500 return;
501 }
502 cb.iload(RESTART_IDX);
503 Label dflt = cb.newLabel();
504 Label[] caseTargets = new Label[labelConstants.length];
505 Label[] caseNext = new Label[labelConstants.length];
506 Object[] caseLabels = new Object[labelConstants.length];
507 SwitchCase[] switchCases = new SwitchCase[labelConstants.length];
508 Object lastLabel = null;
509 for (int idx = labelConstants.length - 1; idx >= 0; idx--) {
510 Object currentLabel = labelConstants[idx];
511 Label target = cb.newLabel();
512 Label next;
513 if (lastLabel == null) {
514 next = dflt;
515 } else if (lastLabel.equals(currentLabel)) {
516 next = caseNext[idx + 1];
517 } else {
518 next = caseTargets[idx + 1];
519 }
520 lastLabel = currentLabel;
521 caseTargets[idx] = target;
522 caseNext[idx] = next;
523 caseLabels[idx] = currentLabel;
524 switchCases[idx] = SwitchCase.of(idx, target);
525 }
526 cb.tableswitch(0, labelConstants.length - 1, dflt, Arrays.asList(switchCases));
527 for (int idx = 0; idx < labelConstants.length; idx++) {
528 Label next = caseNext[idx];
529 Object caseLabel = caseLabels[idx];
530 cb.labelBinding(caseTargets[idx]);
531 if (caseLabel instanceof Class<?> classLabel) {
532 if (unconditionalExactnessCheck(selectorType, classLabel)) {
533 //nothing - unconditionally use this case
534 } else if (classLabel.isPrimitive()) {
535 if (!selectorType.isPrimitive() && !Wrapper.isWrapperNumericOrBooleanType(selectorType)) {
536 // Object o = ...
537 // o instanceof Wrapped(float)
538 cb.aload(SELECTOR_OBJ)
539 .instanceOf(Wrapper.forBasicType(classLabel).wrapperClassDescriptor())
540 .ifeq(next);
541 } else if (!unconditionalExactnessCheck(Wrapper.asPrimitiveType(selectorType), classLabel)) {
542 // Integer i = ... or int i = ...
543 // o instanceof float
544 Label notNumber = cb.newLabel();
545 cb.aload(SELECTOR_OBJ)
546 .instanceOf(CD_Number);
547 if (selectorType == long.class || selectorType == float.class || selectorType == double.class ||
548 selectorType == Long.class || selectorType == Float.class || selectorType == Double.class) {
549 cb.ifeq(next);
550 } else {
551 cb.ifeq(notNumber);
552 }
553 cb.aload(SELECTOR_OBJ)
554 .checkcast(CD_Number);
555 if (selectorType == long.class || selectorType == Long.class) {
556 cb.invokevirtual(CD_Number,
557 "longValue",
558 MethodTypeDesc.of(CD_long));
559 } else if (selectorType == float.class || selectorType == Float.class) {
560 cb.invokevirtual(CD_Number,
561 "floatValue",
562 MethodTypeDesc.of(CD_float));
563 } else if (selectorType == double.class || selectorType == Double.class) {
564 cb.invokevirtual(CD_Number,
565 "doubleValue",
566 MethodTypeDesc.of(CD_double));
567 } else {
568 Label compare = cb.newLabel();
569 cb.invokevirtual(CD_Number,
570 "intValue",
571 MethodTypeDesc.of(CD_int))
572 .goto_(compare)
573 .labelBinding(notNumber)
574 .aload(SELECTOR_OBJ)
575 .instanceOf(CD_Character)
576 .ifeq(next)
577 .aload(SELECTOR_OBJ)
578 .checkcast(CD_Character)
579 .invokevirtual(CD_Character,
580 "charValue",
581 MethodTypeDesc.of(CD_char))
582 .labelBinding(compare);
583 }
584
585 TypePairs typePair = TypePairs.of(Wrapper.asPrimitiveType(selectorType), classLabel);
586 String methodName = TypePairs.typePairToName.get(typePair);
587 cb.invokestatic(referenceClassDesc(ExactConversionsSupport.class),
588 methodName,
589 MethodTypeDesc.of(CD_boolean, classDesc(typePair.from)))
590 .ifeq(next);
591 }
592 } else {
593 Optional<ClassDesc> classLabelConstableOpt = classLabel.describeConstable();
594 if (classLabelConstableOpt.isPresent()) {
595 cb.aload(SELECTOR_OBJ)
596 .instanceOf(classLabelConstableOpt.orElseThrow())
597 .ifeq(next);
598 } else {
599 cb.aload(EXTRA_CLASS_LABELS)
600 .loadConstant(extraClassLabels.size())
601 .invokeinterface(CD_List,
602 "get",
603 MethodTypeDesc.of(CD_Object,
604 CD_int))
605 .checkcast(CD_Class)
606 .aload(SELECTOR_OBJ)
607 .invokevirtual(CD_Class,
608 "isInstance",
609 MethodTypeDesc.of(CD_boolean,
610 CD_Object))
611 .ifeq(next);
612 extraClassLabels.add(classLabel);
613 }
614 }
615 } else if (caseLabel instanceof EnumDesc<?> enumLabel) {
616 int enumIdx = enumDescs.size();
617 enumDescs.add(enumLabel);
618 cb.aload(ENUM_CACHE)
619 .loadConstant(enumIdx)
620 .invokestatic(CD_Integer,
621 "valueOf",
622 MethodTypeDesc.of(CD_Integer,
623 CD_int))
624 .aload(SELECTOR_OBJ)
625 .invokeinterface(CD_BiPredicate,
626 "test",
627 MethodTypeDesc.of(CD_boolean,
628 CD_Object,
629 CD_Object))
630 .ifeq(next);
631 } else if (caseLabel instanceof String stringLabel) {
632 cb.ldc(stringLabel)
633 .aload(SELECTOR_OBJ)
634 .invokevirtual(CD_Object,
635 "equals",
636 MethodTypeDesc.of(CD_boolean,
637 CD_Object))
638 .ifeq(next);
639 } else if (caseLabel instanceof Integer integerLabel) {
640 Label compare = cb.newLabel();
641 Label notNumber = cb.newLabel();
642 cb.aload(SELECTOR_OBJ)
643 .instanceOf(CD_Number)
644 .ifeq(notNumber)
645 .aload(SELECTOR_OBJ)
646 .checkcast(CD_Number)
647 .invokevirtual(CD_Number,
648 "intValue",
649 MethodTypeDesc.of(CD_int))
650 .goto_(compare)
651 .labelBinding(notNumber)
652 .aload(SELECTOR_OBJ)
653 .instanceOf(CD_Character)
654 .ifeq(next)
655 .aload(SELECTOR_OBJ)
656 .checkcast(CD_Character)
657 .invokevirtual(CD_Character,
658 "charValue",
659 MethodTypeDesc.of(CD_char))
660 .labelBinding(compare)
661
662 .loadConstant(integerLabel)
663 .if_icmpne(next);
664 } else if ((caseLabel instanceof Long ||
665 caseLabel instanceof Float ||
666 caseLabel instanceof Double ||
667 caseLabel instanceof Boolean)) {
668 if (caseLabel instanceof Boolean c) {
669 cb.loadConstant(c ? 1 : 0);
670 } else {
671 cb.loadConstant((ConstantDesc) caseLabel);
672 }
673 var caseLabelWrapper = Wrapper.forWrapperType(caseLabel.getClass());
674 cb.invokestatic(caseLabelWrapper.wrapperClassDescriptor(),
675 "valueOf",
676 MethodTypeDesc.of(caseLabelWrapper.wrapperClassDescriptor(),
677 caseLabelWrapper.basicClassDescriptor()))
678 .aload(SELECTOR_OBJ)
679 .invokevirtual(CD_Object,
680 "equals",
681 MethodTypeDesc.of(CD_boolean,
682 CD_Object))
683 .ifeq(next);
684 } else {
685 throw new InternalError("Unsupported label type: " +
686 caseLabel.getClass());
687 }
688 cb.loadConstant(idx)
689 .ireturn();
690 }
691 cb.labelBinding(dflt)
692 .loadConstant(labelConstants.length)
693 .ireturn();
694 };
695 }
696
697 /*
698 * Construct the method handle that represents the method int typeSwitch(Object, int, BiPredicate, List)
699 */
700 private static MethodHandle generateTypeSwitch(MethodHandles.Lookup caller, Class<?> selectorType, Object[] labelConstants) {
701 boolean addExtraInfo = needsExtraInfo(selectorType, labelConstants);
702 List<EnumDesc<?>> enumDescs = addExtraInfo ? new ArrayList<>() : null;
703 List<Class<?>> extraClassLabels = addExtraInfo ? new ArrayList<>() : null;
704
705 byte[] classBytes = ClassFile.of().build(ConstantUtils.binaryNameToDesc(typeSwitchClassName(caller.lookupClass())),
706 clb -> {
707 clb.withFlags(AccessFlag.FINAL, (PreviewFeatures.isEnabled()) ? AccessFlag.IDENTITY : AccessFlag.SUPER, AccessFlag.SYNTHETIC)
708 .withMethodBody("typeSwitch",
709 addExtraInfo ? MTD_TYPE_SWITCH_EXTRA : MTD_TYPE_SWITCH,
710 ClassFile.ACC_FINAL | ClassFile.ACC_PUBLIC | ClassFile.ACC_STATIC,
711 generateTypeSwitchSkeleton(selectorType, labelConstants, enumDescs, extraClassLabels));
712 });
713
714 try {
715 // this class is linked at the indy callsite; so define a hidden nestmate
716 MethodHandles.Lookup lookup;
717 lookup = caller.defineHiddenClass(classBytes, true, NESTMATE, STRONG);
718 MethodHandle typeSwitch = lookup.findStatic(lookup.lookupClass(),
719 "typeSwitch",
720 addExtraInfo ? MT_TYPE_SWITCH_EXTRA : MT_TYPE_SWITCH);
721 if (addExtraInfo) {
722 typeSwitch = MethodHandles.insertArguments(typeSwitch, 2, new ResolvedEnumLabels(caller, enumDescs.toArray(new EnumDesc<?>[0])),
723 List.copyOf(extraClassLabels));
724 }
725 return typeSwitch;
726 } catch (Throwable t) {
727 throw new IllegalArgumentException(t);
728 }
729 }
730
731 //based on src/java.base/share/classes/java/lang/invoke/InnerClassLambdaMetafactory.java:
732 private static String typeSwitchClassName(Class<?> targetClass) {
733 String name = targetClass.getName();
734 if (targetClass.isHidden()) {
735 // use the original class name
736 name = name.replace('/', '_');
737 }
738 return name + "$$TypeSwitch";
739 }
740
741 // this method should be in sync with com.sun.tools.javac.code.Types.checkUnconditionallyExactPrimitives
742 private static boolean unconditionalExactnessCheck(Class<?> selectorType, Class<?> targetType) {
743 Wrapper selectorWrapper = Wrapper.forBasicType(selectorType);
744 Wrapper targetWrapper = Wrapper.forBasicType(targetType);
745 if (selectorType.isPrimitive() && targetType.equals(selectorWrapper.wrapperType())) {
746 return true;
747 }
748 else if (selectorType.equals(targetType) ||
749 ((selectorType.equals(byte.class) && !targetType.equals(char.class)) ||
750 (selectorType.equals(short.class) && (selectorWrapper.isStrictSubRangeOf(targetWrapper))) ||
751 (selectorType.equals(char.class) && (selectorWrapper.isStrictSubRangeOf(targetWrapper))) ||
752 (selectorType.equals(int.class) && (targetType.equals(double.class) || targetType.equals(long.class))) ||
753 (selectorType.equals(float.class) && (selectorWrapper.isStrictSubRangeOf(targetWrapper))))) return true;
754 return false;
755 }
756
757 // TypePairs should be in sync with the corresponding record in Lower
758 record TypePairs(Class<?> from, Class<?> to) {
759
760 private static final Map<TypePairs, String> typePairToName = initialize();
761
762 public static TypePairs of(Class<?> from, Class<?> to) {
763 if (from == byte.class || from == short.class || from == char.class) {
764 from = int.class;
765 }
766 return new TypePairs(from, to);
767 }
768
769 public int hashCode() {
770 return 31 * from.hashCode() + to.hashCode();
771 }
772
773 public boolean equals(Object other) {
774 if (other instanceof TypePairs otherPair) {
775 return otherPair.from == from && otherPair.to == to;
776 }
777 return false;
778 }
779
780 public static Map<TypePairs, String> initialize() {
781 Map<TypePairs, String> typePairToName = new HashMap<>();
782 typePairToName.put(new TypePairs(byte.class, char.class), "isIntToCharExact"); // redirected
783 typePairToName.put(new TypePairs(short.class, byte.class), "isIntToByteExact"); // redirected
784 typePairToName.put(new TypePairs(short.class, char.class), "isIntToCharExact"); // redirected
785 typePairToName.put(new TypePairs(char.class, byte.class), "isIntToByteExact"); // redirected
786 typePairToName.put(new TypePairs(char.class, short.class), "isIntToShortExact"); // redirected
787 typePairToName.put(new TypePairs(int.class, byte.class), "isIntToByteExact");
788 typePairToName.put(new TypePairs(int.class, short.class), "isIntToShortExact");
789 typePairToName.put(new TypePairs(int.class, char.class), "isIntToCharExact");
790 typePairToName.put(new TypePairs(int.class, float.class), "isIntToFloatExact");
791 typePairToName.put(new TypePairs(long.class, byte.class), "isLongToByteExact");
792 typePairToName.put(new TypePairs(long.class, short.class), "isLongToShortExact");
793 typePairToName.put(new TypePairs(long.class, char.class), "isLongToCharExact");
794 typePairToName.put(new TypePairs(long.class, int.class), "isLongToIntExact");
795 typePairToName.put(new TypePairs(long.class, float.class), "isLongToFloatExact");
796 typePairToName.put(new TypePairs(long.class, double.class), "isLongToDoubleExact");
797 typePairToName.put(new TypePairs(float.class, byte.class), "isFloatToByteExact");
798 typePairToName.put(new TypePairs(float.class, short.class), "isFloatToShortExact");
799 typePairToName.put(new TypePairs(float.class, char.class), "isFloatToCharExact");
800 typePairToName.put(new TypePairs(float.class, int.class), "isFloatToIntExact");
801 typePairToName.put(new TypePairs(float.class, long.class), "isFloatToLongExact");
802 typePairToName.put(new TypePairs(double.class, byte.class), "isDoubleToByteExact");
803 typePairToName.put(new TypePairs(double.class, short.class), "isDoubleToShortExact");
804 typePairToName.put(new TypePairs(double.class, char.class), "isDoubleToCharExact");
805 typePairToName.put(new TypePairs(double.class, int.class), "isDoubleToIntExact");
806 typePairToName.put(new TypePairs(double.class, long.class), "isDoubleToLongExact");
807 typePairToName.put(new TypePairs(double.class, float.class), "isDoubleToFloatExact");
808 return typePairToName;
809 }
810 }
811 }