1 /*
2 * Copyright (c) 2012, 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.invoke;
27
28 import sun.invoke.util.VerifyAccess;
29 import sun.invoke.util.VerifyType;
30 import sun.invoke.util.Wrapper;
31
32 import java.lang.classfile.*;
33 import java.lang.classfile.attribute.RuntimeVisibleAnnotationsAttribute;
34 import java.lang.classfile.attribute.SourceFileAttribute;
35 import java.lang.classfile.constantpool.ClassEntry;
36 import java.lang.classfile.constantpool.ConstantPoolBuilder;
37 import java.lang.classfile.constantpool.FieldRefEntry;
38 import java.lang.classfile.instruction.SwitchCase;
39 import java.lang.constant.ClassDesc;
40 import java.lang.constant.ConstantDesc;
41 import java.lang.constant.MethodTypeDesc;
42 import java.lang.invoke.LambdaForm.BasicType;
43 import java.lang.invoke.LambdaForm.Name;
44 import java.lang.invoke.LambdaForm.NamedFunction;
45 import java.lang.reflect.Modifier;
46 import java.util.ArrayList;
47 import java.util.Arrays;
48 import java.util.HashMap;
49 import java.util.List;
50 import java.util.function.Consumer;
51 import java.util.stream.Stream;
52 import jdk.internal.constant.MethodTypeDescImpl;
53 import jdk.internal.constant.ReferenceClassDescImpl;
54
55 import static java.lang.classfile.ClassFile.*;
56 import static java.lang.constant.ConstantDescs.*;
57 import static java.lang.invoke.LambdaForm.*;
58 import static java.lang.invoke.LambdaForm.BasicType.*;
59 import static java.lang.invoke.MethodHandleNatives.Constants.*;
60 import static java.lang.invoke.MethodHandleStatics.*;
61 import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
62 import static jdk.internal.constant.ConstantUtils.concat;
63 import static jdk.internal.constant.ConstantUtils.validateInternalClassName;
64
65 /**
66 * Code generation backend for LambdaForm.
67 * <p>
68 * @author John Rose, JSR 292 EG
69 */
70 class InvokerBytecodeGenerator {
71 /** Define class names for convenience. */
72 private static final ClassDesc CD_CasesHolder = ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/MethodHandleImpl$CasesHolder;");
73 private static final ClassDesc CD_DirectMethodHandle = ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/DirectMethodHandle;");
74 private static final ClassDesc CD_MemberName = ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/MemberName;");
75 private static final ClassDesc CD_MethodHandleImpl = ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/MethodHandleImpl;");
76 private static final ClassDesc CD_LambdaForm = ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/LambdaForm;");
77 private static final ClassDesc CD_LambdaForm_Name = ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/LambdaForm$Name;");
78 private static final ClassDesc CD_LoopClauses = ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/MethodHandleImpl$LoopClauses;");
79 private static final ClassDesc CD_Object_array = ReferenceClassDescImpl.ofValidated("[Ljava/lang/Object;");
80 private static final ClassDesc CD_MethodHandle_array = ReferenceClassDescImpl.ofValidated("[Ljava/lang/invoke/MethodHandle;");
81 private static final ClassDesc CD_MethodHandle_array2 = ReferenceClassDescImpl.ofValidated("[[Ljava/lang/invoke/MethodHandle;");
82
83 private static final MethodTypeDesc MTD_boolean_Object = MethodTypeDescImpl.ofValidated(CD_boolean, CD_Object);
84 private static final MethodTypeDesc MTD_Object_int = MethodTypeDescImpl.ofValidated(CD_Object, CD_int);
85 private static final MethodTypeDesc MTD_Object_Class = MethodTypeDescImpl.ofValidated(CD_Object, CD_Class);
86 private static final MethodTypeDesc MTD_Object_Object = MethodTypeDescImpl.ofValidated(CD_Object, CD_Object);
87
88 private static final String CLASS_PREFIX = "java/lang/invoke/LambdaForm$";
89 private static final String SOURCE_PREFIX = "LambdaForm$";
90
91 /** Name of its super class*/
92 static final ClassDesc INVOKER_SUPER_DESC = CD_Object;
93
94 /** Name of new class */
95 private final String name;
96 private final String className;
97 private final ConstantPoolBuilder pool = ConstantPoolBuilder.of();
98 private final ClassEntry classEntry;
99
100 private final LambdaForm lambdaForm;
101 private final String invokerName;
102 private final MethodType invokerType;
103
104 /** Info about local variables in compiled lambda form */
105 private int[] localsMap; // index
106 private Class<?>[] localClasses; // type
107
108 private final List<ClassData> classData = new ArrayList<>();
109
110 private static final MemberName.Factory MEMBERNAME_FACTORY = MemberName.getFactory();
111 private static final Class<?> HOST_CLASS = LambdaForm.class;
112 private static final MethodHandles.Lookup LOOKUP = lookup();
113
114 private static MethodHandles.Lookup lookup() {
115 try {
116 return MethodHandles.privateLookupIn(HOST_CLASS, IMPL_LOOKUP);
117 } catch (IllegalAccessException e) {
118 throw newInternalError(e);
119 }
120 }
121
122 /** Main constructor; other constructors delegate to this one. */
123 private InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize,
124 String name, String invokerName, MethodType invokerType) {
125 int p = invokerName.indexOf('.');
126 if (p > -1) {
127 name = invokerName.substring(0, p);
128 invokerName = invokerName.substring(p + 1);
129 }
130 if (dumper().isEnabled()) {
131 name = makeDumpableClassName(name);
132 }
133 this.name = name;
134 this.className = CLASS_PREFIX.concat(name);
135 validateInternalClassName(name);
136 this.classEntry = pool.classEntry(ReferenceClassDescImpl.ofValidated(concat("L", className, ";")));
137 this.lambdaForm = lambdaForm;
138 this.invokerName = invokerName;
139 this.invokerType = invokerType;
140 this.localsMap = new int[localsMapSize+1]; // last entry of localsMap is count of allocated local slots
141 this.localClasses = new Class<?>[localsMapSize+1];
142 }
143
144 /** For generating LambdaForm interpreter entry points. */
145 private InvokerBytecodeGenerator(String name, String invokerName, MethodType invokerType) {
146 this(null, invokerType.parameterCount(),
147 name, invokerName, invokerType);
148 MethodType mt = invokerType.erase();
149 // Create an array to map name indexes to locals indexes.
150 localsMap[0] = 0; // localsMap has at least one element
151 for (int i = 1, index = 0; i < localsMap.length; i++) {
152 Class<?> cl = mt.parameterType(i - 1);
153 index += (cl == long.class || cl == double.class) ? 2 : 1;
154 localsMap[i] = index;
155 }
156 }
157
158 /** For generating customized code for a single LambdaForm. */
159 private InvokerBytecodeGenerator(String name, LambdaForm form, MethodType invokerType) {
160 this(name, form.lambdaName(), form, invokerType);
161 }
162
163 /** For generating customized code for a single LambdaForm. */
164 InvokerBytecodeGenerator(String name, String invokerName,
165 LambdaForm form, MethodType invokerType) {
166 this(form, form.names.length,
167 name, invokerName, invokerType);
168 // Create an array to map name indexes to locals indexes.
169 Name[] names = form.names;
170 for (int i = 0, index = 0; i < localsMap.length; i++) {
171 localsMap[i] = index;
172 if (i < names.length) {
173 BasicType type = names[i].type();
174 index += type.basicTypeSlots();
175 }
176 }
177 }
178
179 /** instance counters for dumped classes */
180 private static final HashMap<String,Integer> DUMP_CLASS_FILES_COUNTERS =
181 dumper().isEnabled() ? new HashMap<>(): null;
182
183 private static String makeDumpableClassName(String className) {
184 Integer ctr;
185 synchronized (DUMP_CLASS_FILES_COUNTERS) {
186 ctr = DUMP_CLASS_FILES_COUNTERS.get(className);
187 if (ctr == null) ctr = 0;
188 DUMP_CLASS_FILES_COUNTERS.put(className, ctr+1);
189 }
190
191 var buf = new StringBuilder(className.length() + 3).append(className);
192 int ctrVal = ctr;
193 if (ctrVal < 10) {
194 buf.repeat('0', 2);
195 } else if (ctrVal < 100) {
196 buf.append('0');
197 }
198 buf.append(ctrVal);
199 return buf.toString();
200 }
201
202 record ClassData(FieldRefEntry field, Object value) {}
203
204 FieldRefEntry classData(ClassFileBuilder<?, ?> cfb, Object arg, ClassDesc desc) {
205 // unique static variable name
206 String name;
207 List<ClassData> classData = this.classData;
208 if (dumper().isEnabled()) {
209 Class<?> c = arg.getClass();
210 while (c.isArray()) {
211 c = c.getComponentType();
212 }
213 name = "_DATA_" + c.getSimpleName() + "_" + classData.size();
214 } else {
215 name = "_D_" + classData.size();
216 }
217 var field = pool.fieldRefEntry(classEntry, pool.nameAndTypeEntry(name, desc));
218 classData.add(new ClassData(field, arg));
219 return field;
220 }
221
222 /**
223 * Extract the MemberName of a newly-defined method.
224 */
225 private MemberName loadMethod(byte[] classFile) {
226 Class<?> invokerClass = LOOKUP.makeHiddenClassDefiner(className, classFile, dumper())
227 .defineClass(true, classDataValues());
228 return resolveInvokerMember(invokerClass, invokerName, invokerType);
229 }
230
231 private static MemberName resolveInvokerMember(Class<?> invokerClass, String name, MethodType type) {
232 MemberName member = new MemberName(invokerClass, name, type, REF_invokeStatic);
233 try {
234 member = MEMBERNAME_FACTORY.resolveOrFail(REF_invokeStatic, member,
235 HOST_CLASS, LM_TRUSTED,
236 ReflectiveOperationException.class);
237 } catch (ReflectiveOperationException e) {
238 throw newInternalError(e);
239 }
240 return member;
241 }
242
243 /**
244 * Set up class file generation.
245 */
246 private byte[] classFileSetup(Consumer<? super ClassBuilder> config) {
247 try {
248 return ClassFile.of().build(classEntry, pool, new Consumer<>() {
249 @Override
250 public void accept(ClassBuilder clb) {
251 clb.withFlags(ACC_ABSTRACT | ACC_SUPER)
252 .withSuperclass(INVOKER_SUPER_DESC)
253 .with(SourceFileAttribute.of(clb.constantPool().utf8Entry(SOURCE_PREFIX + name)));
254 config.accept(clb);
255 }
256 });
257 } catch (RuntimeException e) {
258 throw new BytecodeGenerationException(e);
259 }
260 }
261
262 private void methodSetup(ClassBuilder clb, Consumer<? super MethodBuilder> config) {
263 var invokerDesc = methodDesc(invokerType);
264 clb.withMethod(invokerName, invokerDesc, ACC_STATIC, config);
265 }
266
267 /**
268 * Returns the class data object that will be passed to `Lookup.defineHiddenClassWithClassData`.
269 * The classData is loaded in the <clinit> method of the generated class.
270 * If the class data contains only one single object, this method returns that single object.
271 * If the class data contains more than one objects, this method returns a List.
272 *
273 * This method returns null if no class data.
274 */
275 private Object classDataValues() {
276 final List<ClassData> cd = classData;
277 int size = cd.size();
278 return switch (size) {
279 case 0 -> null; // special case (classData is not used by <clinit>)
280 case 1 -> cd.get(0).value; // special case (single object)
281 case 2 -> List.of(cd.get(0).value, cd.get(1).value);
282 case 3 -> List.of(cd.get(0).value, cd.get(1).value, cd.get(2).value);
283 case 4 -> List.of(cd.get(0).value, cd.get(1).value, cd.get(2).value, cd.get(3).value);
284 default -> {
285 Object[] data = new Object[size];
286 for (int i = 0; i < size; i++) {
287 data[i] = classData.get(i).value;
288 }
289 yield List.of(data);
290 }
291 };
292 }
293
294 /*
295 * <clinit> to initialize the static final fields with the live class data
296 * LambdaForms can't use condy due to bootstrapping issue.
297 */
298 static void clinit(ClassBuilder clb, ClassEntry classEntry, List<ClassData> classData) {
299 if (classData.isEmpty())
300 return;
301
302 clb.withMethodBody(CLASS_INIT_NAME, MTD_void, ACC_STATIC, new Consumer<>() {
303 @Override
304 public void accept(CodeBuilder cob) {
305 cob.ldc(classEntry)
306 .invokestatic(CD_MethodHandles, "classData", MTD_Object_Class);
307 int size = classData.size();
308 if (size == 1) {
309 var field = classData.getFirst().field;
310 // add the static field
311 clb.withField(field.name(), field.type(), ACC_STATIC | ACC_FINAL);
312
313 var ft = field.typeSymbol();
314 if (ft != CD_Object)
315 cob.checkcast(ft);
316 cob.putstatic(field);
317 } else {
318 cob.checkcast(CD_List)
319 .astore(0);
320 int index = 0;
321 var listGet = cob.constantPool().interfaceMethodRefEntry(CD_List, "get", MTD_Object_int);
322 for (int i = 0; i < size; i++) {
323 var field = classData.get(i).field;
324 // add the static field
325 clb.withField(field.name(), field.type(), ACC_STATIC | ACC_FINAL);
326 // initialize the static field
327 cob.aload(0)
328 .loadConstant(index++)
329 .invokeinterface(listGet);
330 var ft = field.typeSymbol();
331 if (ft != CD_Object)
332 cob.checkcast(ft);
333 cob.putstatic(field);
334 }
335 }
336 cob.return_();
337 }
338 });
339 }
340
341 private void emitLoadInsn(CodeBuilder cob, TypeKind type, int index) {
342 cob.loadLocal(type, localsMap[index]);
343 }
344
345 private void emitStoreInsn(CodeBuilder cob, TypeKind type, int index) {
346 cob.storeLocal(type, localsMap[index]);
347 }
348
349 /**
350 * Emit a boxing call.
351 */
352 private void emitBoxing(CodeBuilder cob, TypeKind tk) {
353 TypeConvertingMethodAdapter.box(cob, tk);
354 }
355
356 /**
357 * Emit an unboxing call (plus preceding checkcast).
358 */
359 private void emitUnboxing(CodeBuilder cob, TypeKind target) {
360 switch (target) {
361 case BOOLEAN -> emitReferenceCast(cob, Boolean.class, null);
362 case CHAR -> emitReferenceCast(cob, Character.class, null);
363 case BYTE, DOUBLE, FLOAT, INT, LONG, SHORT ->
364 emitReferenceCast(cob, Number.class, null);
365 default -> {}
366 }
367 TypeConvertingMethodAdapter.unbox(cob, target);
368 }
369
370 /**
371 * Emit an implicit conversion for an argument which must be of the given pclass.
372 * This is usually a no-op, except when pclass is a subword type or a reference other than Object or an interface.
373 *
374 * @param ptype type of value present on stack
375 * @param pclass type of value required on stack
376 * @param arg compile-time representation of value on stack (Node, constant) or null if none
377 */
378 private void emitImplicitConversion(CodeBuilder cob, BasicType ptype, Class<?> pclass, Object arg) {
379 assert(basicType(pclass) == ptype); // boxing/unboxing handled by caller
380 if (pclass == ptype.basicTypeClass() && ptype != L_TYPE)
381 return; // nothing to do
382 switch (ptype) {
383 case L_TYPE:
384 if (VerifyType.isNullConversion(Object.class, pclass, false)) {
385 if (PROFILE_LEVEL > 0)
386 emitReferenceCast(cob, Object.class, arg);
387 return;
388 }
389 emitReferenceCast(cob, pclass, arg);
390 return;
391 case I_TYPE:
392 if (!VerifyType.isNullConversion(int.class, pclass, false))
393 emitPrimCast(cob, ptype.basicTypeKind(), TypeKind.from(pclass));
394 return;
395 }
396 throw newInternalError("bad implicit conversion: tc="+ptype+": "+pclass);
397 }
398
399 /** Update localClasses type map. Return true if the information is already present. */
400 private boolean assertStaticType(Class<?> cls, Name n) {
401 int local = n.index();
402 Class<?> aclass = localClasses[local];
403 if (aclass != null && (aclass == cls || cls.isAssignableFrom(aclass))) {
404 return true; // type info is already present
405 } else if (aclass == null || aclass.isAssignableFrom(cls)) {
406 localClasses[local] = cls; // type info can be improved
407 }
408 return false;
409 }
410
411 private void emitReferenceCast(CodeBuilder cob, Class<?> cls, Object arg) {
412 Name writeBack = null; // local to write back result
413 if (arg instanceof Name n) {
414 if (lambdaForm.useCount(n) > 1) {
415 // This guy gets used more than once.
416 writeBack = n;
417 if (assertStaticType(cls, n)) {
418 return; // this cast was already performed
419 }
420 }
421 }
422 if (isStaticallyNameable(cls)) {
423 ClassDesc sig = classDesc(cls);
424 cob.checkcast(sig);
425 } else {
426 cob.getstatic(classData(cob, cls, CD_Class))
427 .swap()
428 .invokevirtual(CD_Class, "cast", MTD_Object_Object);
429 if (Object[].class.isAssignableFrom(cls))
430 cob.checkcast(CD_Object_array);
431 else if (PROFILE_LEVEL > 0)
432 cob.checkcast(CD_Object);
433 }
434 if (writeBack != null) {
435 cob.dup();
436 emitStoreInsn(cob, TypeKind.REFERENCE, writeBack.index());
437 }
438 }
439
440 private static MemberName resolveFrom(String name, MethodType type, Class<?> holder) {
441 assert(!UNSAFE.shouldBeInitialized(holder)) : holder + "not initialized";
442 MemberName member = new MemberName(holder, name, type, REF_invokeStatic);
443 MemberName resolvedMember = MemberName.getFactory().resolveOrNull(REF_invokeStatic, member, holder, LM_TRUSTED);
444 traceLambdaForm(name, type, holder, resolvedMember);
445 return resolvedMember;
446 }
447
448 private static MemberName lookupPregenerated(LambdaForm form, MethodType invokerType) {
449 if (form.customized != null) {
450 // No pre-generated version for customized LF
451 return null;
452 }
453 String name = form.kind.methodName;
454 switch (form.kind) {
455 case BOUND_REINVOKER: {
456 name = name + "_" + BoundMethodHandle.speciesDataFor(form).key();
457 return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class);
458 }
459 case DELEGATE: return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class);
460 case ZERO: // fall-through
461 case IDENTITY: {
462 name = name + "_" + form.returnType().basicTypeChar();
463 return resolveFrom(name, invokerType, LambdaForm.Holder.class);
464 }
465 case EXACT_INVOKER: // fall-through
466 case EXACT_LINKER: // fall-through
467 case LINK_TO_CALL_SITE: // fall-through
468 case LINK_TO_TARGET_METHOD: // fall-through
469 case GENERIC_INVOKER: // fall-through
470 case GENERIC_LINKER: return resolveFrom(name, invokerType, Invokers.Holder.class);
471 case GET_REFERENCE: // fall-through
472 case GET_BOOLEAN: // fall-through
473 case GET_BYTE: // fall-through
474 case GET_CHAR: // fall-through
475 case GET_SHORT: // fall-through
476 case GET_INT: // fall-through
477 case GET_LONG: // fall-through
478 case GET_FLOAT: // fall-through
479 case GET_DOUBLE: // fall-through
480 case PUT_REFERENCE: // fall-through
481 case PUT_BOOLEAN: // fall-through
482 case PUT_BYTE: // fall-through
483 case PUT_CHAR: // fall-through
484 case PUT_SHORT: // fall-through
485 case PUT_INT: // fall-through
486 case PUT_LONG: // fall-through
487 case PUT_FLOAT: // fall-through
488 case PUT_DOUBLE: // fall-through
489 case DIRECT_NEW_INVOKE_SPECIAL: // fall-through
490 case DIRECT_INVOKE_INTERFACE: // fall-through
491 case DIRECT_INVOKE_SPECIAL: // fall-through
492 case DIRECT_INVOKE_SPECIAL_IFC: // fall-through
493 case DIRECT_INVOKE_STATIC: // fall-through
494 case DIRECT_INVOKE_STATIC_INIT: // fall-through
495 case DIRECT_INVOKE_VIRTUAL: return resolveFrom(name, invokerType, DirectMethodHandle.Holder.class);
496 }
497 return null;
498 }
499
500 /**
501 * Generate customized bytecode for a given LambdaForm.
502 */
503 static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) {
504 MemberName pregenerated = lookupPregenerated(form, invokerType);
505 if (pregenerated != null) return pregenerated; // pre-generated bytecode
506
507 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("MH", form, invokerType);
508 return g.loadMethod(g.generateCustomizedCodeBytes());
509 }
510
511 /** Generates code to check that actual receiver and LambdaForm matches */
512 private boolean checkActualReceiver(CodeBuilder cob) {
513 // Expects MethodHandle on the stack and actual receiver MethodHandle in slot #0
514 cob.dup()
515 .aload(0)
516 .invokestatic(CD_MethodHandleImpl, "assertSame", MethodTypeDescImpl.ofValidated(CD_void, CD_Object, CD_Object));
517 return true;
518 }
519
520 static final Annotation DONTINLINE = Annotation.of(ReferenceClassDescImpl.ofValidated("Ljdk/internal/vm/annotation/DontInline;"));
521 static final Annotation FORCEINLINE = Annotation.of(ReferenceClassDescImpl.ofValidated("Ljdk/internal/vm/annotation/ForceInline;"));
522 static final Annotation HIDDEN = Annotation.of(ReferenceClassDescImpl.ofValidated("Ljdk/internal/vm/annotation/Hidden;"));
523 static final Annotation INJECTEDPROFILE = Annotation.of(ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/InjectedProfile;"));
524 static final Annotation LF_COMPILED = Annotation.of(ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/LambdaForm$Compiled;"));
525
526 // Suppress method in backtraces displayed to the user, mark this method as
527 // a compiled LambdaForm, then either force or prohibit inlining.
528 public static final RuntimeVisibleAnnotationsAttribute LF_DONTINLINE_ANNOTATIONS = RuntimeVisibleAnnotationsAttribute.of(HIDDEN, LF_COMPILED, DONTINLINE);
529 public static final RuntimeVisibleAnnotationsAttribute LF_FORCEINLINE_ANNOTATIONS = RuntimeVisibleAnnotationsAttribute.of(HIDDEN, LF_COMPILED, FORCEINLINE);
530
531 /**
532 * Generate an invoker method for the passed {@link LambdaForm}.
533 */
534 private byte[] generateCustomizedCodeBytes() {
535 final byte[] classFile = classFileSetup(new Consumer<>() {
536 @Override
537 public void accept(ClassBuilder clb) {
538 addMethod(clb, true);
539 clinit(clb, classEntry, classData);
540 bogusMethod(clb, lambdaForm);
541 }
542 });
543 return classFile;
544 }
545
546 void addMethod(ClassBuilder clb, boolean alive) {
547 methodSetup(clb, new Consumer<>() {
548 @Override
549 public void accept(MethodBuilder mb) {
550
551 if (lambdaForm.forceInline) {
552 mb.accept(LF_FORCEINLINE_ANNOTATIONS);
553 } else {
554 mb.accept(LF_DONTINLINE_ANNOTATIONS);
555 }
556
557 if (alive) {
558 classData(mb, lambdaForm, CD_LambdaForm); // keep LambdaForm instance & its compiled form lifetime tightly coupled.
559 }
560
561 mb.withCode(new Consumer<>() {
562 @Override
563 public void accept(CodeBuilder cob) {
564 if (lambdaForm.customized != null) {
565 // Since LambdaForm is customized for a particular MethodHandle, it's safe to substitute
566 // receiver MethodHandle (at slot #0) with an embedded constant and use it instead.
567 // It enables more efficient code generation in some situations, since embedded constants
568 // are compile-time constants for JIT compiler.
569 cob.getstatic(classData(cob, lambdaForm.customized, CD_MethodHandle));
570 assert(checkActualReceiver(cob)); // expects MethodHandle on top of the stack
571 cob.astore(0);
572 }
573
574 // iterate over the form's names, generating bytecode instructions for each
575 // start iterating at the first name following the arguments
576 Name onStack = null;
577 for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) {
578 Name name = lambdaForm.names[i];
579
580 emitStoreResult(cob, onStack);
581 onStack = name; // unless otherwise modified below
582 MethodHandleImpl.Intrinsic intr = name.function.intrinsicName();
583 switch (intr) {
584 case SELECT_ALTERNATIVE:
585 assert lambdaForm.isSelectAlternative(i);
586 if (PROFILE_GWT) {
587 assert(name.arguments[0] instanceof Name n &&
588 n.refersTo(MethodHandleImpl.class, "profileBoolean"));
589 mb.with(RuntimeVisibleAnnotationsAttribute.of(List.of(INJECTEDPROFILE)));
590 }
591 onStack = emitSelectAlternative(cob, name, lambdaForm.names[i+1]);
592 i++; // skip MH.invokeBasic of the selectAlternative result
593 continue;
594 case GUARD_WITH_CATCH:
595 assert lambdaForm.isGuardWithCatch(i);
596 onStack = emitGuardWithCatch(cob, i);
597 i += 2; // jump to the end of GWC idiom
598 continue;
599 case TRY_FINALLY:
600 assert lambdaForm.isTryFinally(i);
601 onStack = emitTryFinally(cob, i);
602 i += 2; // jump to the end of the TF idiom
603 continue;
604 case TABLE_SWITCH:
605 assert lambdaForm.isTableSwitch(i);
606 int numCases = (Integer) name.function.intrinsicData();
607 onStack = emitTableSwitch(cob, i, numCases);
608 i += 2; // jump to the end of the TS idiom
609 continue;
610 case LOOP:
611 assert lambdaForm.isLoop(i);
612 onStack = emitLoop(cob, i);
613 i += 2; // jump to the end of the LOOP idiom
614 continue;
615 case ARRAY_LOAD:
616 emitArrayLoad(cob, name);
617 continue;
618 case ARRAY_STORE:
619 emitArrayStore(cob, name);
620 continue;
621 case ARRAY_LENGTH:
622 emitArrayLength(cob, name);
623 continue;
624 case IDENTITY:
625 assert(name.arguments.length == 1);
626 emitPushArguments(cob, name, 0);
627 continue;
628 case ZERO:
629 assert(name.arguments.length == 0);
630 cob.loadConstant((ConstantDesc)name.type.basicTypeWrapper().zero());
631 continue;
632 case NONE:
633 // no intrinsic associated
634 break;
635 default:
636 throw newInternalError("Unknown intrinsic: "+intr);
637 }
638
639 MemberName member = name.function.member();
640 if (isStaticallyInvocable(member)) {
641 emitStaticInvoke(cob, member, name);
642 } else {
643 emitInvoke(cob, name);
644 }
645 }
646
647 // return statement
648 emitReturn(cob, onStack);
649 }
650 });
651 }
652 });
653 }
654
655 /**
656 * The BytecodeGenerationException.
657 */
658 @SuppressWarnings("serial")
659 static final class BytecodeGenerationException extends RuntimeException {
660 BytecodeGenerationException(Exception cause) {
661 super(cause);
662 }
663 }
664
665 void emitArrayLoad(CodeBuilder cob, Name name) {
666 Class<?> elementType = name.function.methodType().parameterType(0).getComponentType();
667 assert elementType != null;
668 emitPushArguments(cob, name, 0);
669 if (elementType.isPrimitive()) {
670 cob.arrayLoad(TypeKind.from(elementType));
671 } else {
672 cob.aaload();
673 }
674 }
675
676 void emitArrayStore(CodeBuilder cob, Name name) {
677 Class<?> elementType = name.function.methodType().parameterType(0).getComponentType();
678 assert elementType != null;
679 emitPushArguments(cob, name, 0);
680 if (elementType.isPrimitive()) {
681 cob.arrayStore(TypeKind.from(elementType));
682 } else {
683 cob.aastore();
684 }
685 }
686
687 void emitArrayLength(CodeBuilder cob, Name name) {
688 assert name.function.methodType().parameterType(0).isArray();
689 emitPushArguments(cob, name, 0);
690 cob.arraylength();
691 }
692
693 /**
694 * Emit an invoke for the given name.
695 */
696 void emitInvoke(CodeBuilder cob, Name name) {
697 assert(!name.isLinkerMethodInvoke()); // should use the static path for these
698 if (true) {
699 // push receiver
700 MethodHandle target = name.function.resolvedHandle();
701 assert(target != null) : name.exprString();
702 cob.getstatic(classData(cob, target, CD_MethodHandle));
703 emitReferenceCast(cob, MethodHandle.class, target);
704 } else {
705 // load receiver
706 cob.aload(0);
707 emitReferenceCast(cob, MethodHandle.class, null);
708 cob.getfield(CD_MethodHandle, "form", CD_LambdaForm)
709 .getfield(CD_LambdaForm, "names", CD_LambdaForm_Name);
710 // TODO more to come
711 }
712
713 // push arguments
714 emitPushArguments(cob, name, 0);
715
716 // invocation
717 MethodType type = name.function.methodType();
718 cob.invokevirtual(CD_MethodHandle, "invokeBasic", methodDesc(type.basicType()));
719 }
720
721 private static final Class<?>[] STATICALLY_INVOCABLE_PACKAGES = {
722 // Sample classes from each package we are willing to bind to statically:
723 java.lang.Object.class,
724 java.util.Arrays.class,
725 jdk.internal.misc.Unsafe.class
726 //MethodHandle.class already covered
727 };
728
729 static boolean isStaticallyInvocable(NamedFunction ... functions) {
730 for (NamedFunction nf : functions) {
731 if (!isStaticallyInvocable(nf.member())) {
732 return false;
733 }
734 }
735 return true;
736 }
737
738 static boolean isStaticallyInvocable(Name name) {
739 return isStaticallyInvocable(name.function.member());
740 }
741
742 static boolean isStaticallyInvocable(MemberName member) {
743 if (member == null) return false;
744 if (member.isConstructor()) return false;
745 Class<?> cls = member.getDeclaringClass();
746 // Fast-path non-private members declared by MethodHandles, which is a common
747 // case
748 if (MethodHandle.class.isAssignableFrom(cls) && !member.isPrivate()) {
749 assert(isStaticallyInvocableType(member.getMethodOrFieldType()));
750 return true;
751 }
752 if (cls.isArray() || cls.isPrimitive())
753 return false; // FIXME
754 if (cls.isAnonymousClass() || cls.isLocalClass())
755 return false; // inner class of some sort
756 if (cls.getClassLoader() != MethodHandle.class.getClassLoader())
757 return false; // not on BCP
758 if (cls.isHidden())
759 return false;
760 if (!isStaticallyInvocableType(member.getMethodOrFieldType()))
761 return false;
762 if (!member.isPrivate() && VerifyAccess.isSamePackage(MethodHandle.class, cls))
763 return true; // in java.lang.invoke package
764 if (member.isPublic() && isStaticallyNameable(cls))
765 return true;
766 return false;
767 }
768
769 private static boolean isStaticallyInvocableType(MethodType mtype) {
770 if (!isStaticallyNameable(mtype.returnType()))
771 return false;
772 for (Class<?> ptype : mtype.ptypes())
773 if (!isStaticallyNameable(ptype))
774 return false;
775 return true;
776 }
777
778 static boolean isStaticallyNameable(Class<?> cls) {
779 if (cls == Object.class)
780 return true;
781 if (MethodHandle.class.isAssignableFrom(cls)) {
782 assert(!cls.isHidden());
783 return true;
784 }
785 while (cls.isArray())
786 cls = cls.getComponentType();
787 if (cls.isPrimitive())
788 return true; // int[].class, for example
789 if (cls.isHidden())
790 return false;
791 // could use VerifyAccess.isClassAccessible but the following is a safe approximation
792 if (cls.getClassLoader() != Object.class.getClassLoader())
793 return false;
794 if (VerifyAccess.isSamePackage(MethodHandle.class, cls))
795 return true;
796 if (!Modifier.isPublic(cls.getModifiers()))
797 return false;
798 for (Class<?> pkgcls : STATICALLY_INVOCABLE_PACKAGES) {
799 if (VerifyAccess.isSamePackage(pkgcls, cls))
800 return true;
801 }
802 return false;
803 }
804
805 void emitStaticInvoke(CodeBuilder cob, Name name) {
806 emitStaticInvoke(cob, name.function.member(), name);
807 }
808
809 /**
810 * Emit an invoke for the given name, using the MemberName directly.
811 */
812 void emitStaticInvoke(CodeBuilder cob, MemberName member, Name name) {
813 assert(member.equals(name.function.member()));
814 Class<?> defc = member.getDeclaringClass();
815 ClassDesc cdesc = classDesc(defc);
816 String mname = member.getName();
817 byte refKind = member.getReferenceKind();
818 if (refKind == REF_invokeSpecial) {
819 // in order to pass the verifier, we need to convert this to invokevirtual in all cases
820 assert(member.canBeStaticallyBound()) : member;
821 refKind = REF_invokeVirtual;
822 }
823
824 assert(!(member.getDeclaringClass().isInterface() && refKind == REF_invokeVirtual));
825
826 // push arguments
827 emitPushArguments(cob, name, 0);
828
829 // invocation
830 if (member.isMethod()) {
831 var methodTypeDesc = methodDesc(member.getMethodType());
832 cob.invoke(refKindOpcode(refKind), cdesc, mname, methodTypeDesc,
833 member.getDeclaringClass().isInterface());
834 } else {
835 var fieldTypeDesc = classDesc(member.getFieldType());
836 cob.fieldAccess(refKindOpcode(refKind), cdesc, mname, fieldTypeDesc);
837 }
838 // Issue a type assertion for the result, so we can avoid casts later.
839 if (name.type == L_TYPE) {
840 Class<?> rtype = member.getInvocationType().returnType();
841 assert(!rtype.isPrimitive());
842 if (rtype != Object.class && !rtype.isInterface()) {
843 assertStaticType(rtype, name);
844 }
845 }
846 }
847
848 Opcode refKindOpcode(byte refKind) {
849 switch (refKind) {
850 case REF_invokeVirtual: return Opcode.INVOKEVIRTUAL;
851 case REF_invokeStatic: return Opcode.INVOKESTATIC;
852 case REF_invokeSpecial: return Opcode.INVOKESPECIAL;
853 case REF_invokeInterface: return Opcode.INVOKEINTERFACE;
854 case REF_getField: return Opcode.GETFIELD;
855 case REF_putField: return Opcode.PUTFIELD;
856 case REF_getStatic: return Opcode.GETSTATIC;
857 case REF_putStatic: return Opcode.PUTSTATIC;
858 }
859 throw new InternalError("refKind="+refKind);
860 }
861
862 /**
863 * Emit bytecode for the selectAlternative idiom.
864 *
865 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithTest):
866 * <blockquote><pre>{@code
867 * Lambda(a0:L,a1:I)=>{
868 * t2:I=foo.test(a1:I);
869 * t3:L=MethodHandleImpl.selectAlternative(t2:I,(MethodHandle(int)int),(MethodHandle(int)int));
870 * t4:I=MethodHandle.invokeBasic(t3:L,a1:I);t4:I}
871 * }</pre></blockquote>
872 */
873 private Name emitSelectAlternative(CodeBuilder cob, Name selectAlternativeName, Name invokeBasicName) {
874 assert isStaticallyInvocable(invokeBasicName);
875
876 Name receiver = (Name) invokeBasicName.arguments[0];
877
878 Label L_fallback = cob.newLabel();
879 Label L_done = cob.newLabel();
880
881 // load test result
882 emitPushArgument(cob, selectAlternativeName, 0);
883
884 // if_icmpne L_fallback
885 cob.ifeq(L_fallback);
886
887 // invoke selectAlternativeName.arguments[1]
888 Class<?>[] preForkClasses = localClasses.clone();
889 emitPushArgument(cob, selectAlternativeName, 1); // get 2nd argument of selectAlternative
890 emitStoreInsn(cob, TypeKind.REFERENCE, receiver.index()); // store the MH in the receiver slot
891 emitStaticInvoke(cob, invokeBasicName);
892
893 // goto L_done
894 cob.goto_w(L_done)
895 // L_fallback:
896 .labelBinding(L_fallback);
897
898 // invoke selectAlternativeName.arguments[2]
899 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
900 emitPushArgument(cob, selectAlternativeName, 2); // get 3rd argument of selectAlternative
901 emitStoreInsn(cob, TypeKind.REFERENCE, receiver.index()); // store the MH in the receiver slot
902 emitStaticInvoke(cob, invokeBasicName);
903
904 // L_done:
905 cob.labelBinding(L_done);
906 // for now do not bother to merge typestate; just reset to the dominator state
907 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
908
909 return invokeBasicName; // return what's on stack
910 }
911
912 /**
913 * Emit bytecode for the guardWithCatch idiom.
914 *
915 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithCatch):
916 * <blockquote><pre>{@code
917 * guardWithCatch=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{
918 * t8:L=MethodHandle.invokeBasic(a4:L,a6:L,a7:L);
919 * t9:L=MethodHandleImpl.guardWithCatch(a1:L,a2:L,a3:L,t8:L);
920 * t10:I=MethodHandle.invokeBasic(a5:L,t9:L);t10:I}
921 * }</pre></blockquote>
922 *
923 * It is compiled into bytecode equivalent of the following code:
924 * <blockquote><pre>{@code
925 * try {
926 * return a1.invokeBasic(a6, a7);
927 * } catch (Throwable e) {
928 * if (!a2.isInstance(e)) throw e;
929 * return a3.invokeBasic(ex, a6, a7);
930 * }}</pre></blockquote>
931 */
932 private Name emitGuardWithCatch(CodeBuilder cob, int pos) {
933 Name args = lambdaForm.names[pos];
934 Name invoker = lambdaForm.names[pos+1];
935 Name result = lambdaForm.names[pos+2];
936
937 Label L_startBlock = cob.newLabel();
938 Label L_endBlock = cob.newLabel();
939 Label L_handler = cob.newLabel();
940 Label L_done = cob.newLabel();
941
942 Class<?> returnType = result.function.resolvedHandle().type().returnType();
943 MethodType type = args.function.resolvedHandle().type()
944 .dropParameterTypes(0,1)
945 .changeReturnType(returnType);
946
947 cob.exceptionCatch(L_startBlock, L_endBlock, L_handler, CD_Throwable)
948 // Normal case
949 .labelBinding(L_startBlock);
950 // load target
951 emitPushArgument(cob, invoker, 0);
952 emitPushArguments(cob, args, 1); // skip 1st argument: method handle
953 cob.invokevirtual(CD_MethodHandle, "invokeBasic", methodDesc(type.basicType()))
954 .labelBinding(L_endBlock)
955 .goto_w(L_done)
956 // Exceptional case
957 .labelBinding(L_handler)
958 // Check exception's type
959 .dup();
960 // load exception class
961 emitPushArgument(cob, invoker, 1);
962 cob.swap()
963 .invokevirtual(CD_Class, "isInstance", MTD_boolean_Object);
964 Label L_rethrow = cob.newLabel();
965 cob.ifeq(L_rethrow);
966
967 // Invoke catcher
968 // load catcher
969 emitPushArgument(cob, invoker, 2);
970 cob.swap();
971 emitPushArguments(cob, args, 1); // skip 1st argument: method handle
972 MethodType catcherType = type.insertParameterTypes(0, Throwable.class);
973 cob.invokevirtual(CD_MethodHandle, "invokeBasic", methodDesc(catcherType.basicType()))
974 .goto_w(L_done)
975 .labelBinding(L_rethrow)
976 .athrow()
977 .labelBinding(L_done);
978
979 return result;
980 }
981
982 /**
983 * Emit bytecode for the tryFinally idiom.
984 * <p>
985 * The pattern looks like (Cf. MethodHandleImpl.makeTryFinally):
986 * <blockquote><pre>{@code
987 * // a0: BMH
988 * // a1: target, a2: cleanup
989 * // a3: box, a4: unbox
990 * // a5 (and following): arguments
991 * tryFinally=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L)=>{
992 * t6:L=MethodHandle.invokeBasic(a3:L,a5:L); // box the arguments into an Object[]
993 * t7:L=MethodHandleImpl.tryFinally(a1:L,a2:L,t6:L); // call the tryFinally executor
994 * t8:L=MethodHandle.invokeBasic(a4:L,t7:L);t8:L} // unbox the result; return the result
995 * }</pre></blockquote>
996 * <p>
997 * It is compiled into bytecode equivalent to the following code:
998 * <blockquote><pre>{@code
999 * Throwable t;
1000 * Object r;
1001 * try {
1002 * r = a1.invokeBasic(a5);
1003 * } catch (Throwable thrown) {
1004 * t = thrown;
1005 * throw t;
1006 * } finally {
1007 * r = a2.invokeBasic(t, r, a5);
1008 * }
1009 * return r;
1010 * }</pre></blockquote>
1011 * <p>
1012 * Specifically, the bytecode will have the following form (the stack effects are given for the beginnings of
1013 * blocks, and for the situations after executing the given instruction - the code will have a slightly different
1014 * shape if the return type is {@code void}):
1015 * <blockquote><pre>{@code
1016 * TRY: (--)
1017 * load target (-- target)
1018 * load args (-- args... target)
1019 * INVOKEVIRTUAL MethodHandle.invokeBasic (depends)
1020 * FINALLY_NORMAL: (-- r_2nd* r)
1021 * store returned value (--)
1022 * load cleanup (-- cleanup)
1023 * ACONST_NULL (-- t cleanup)
1024 * load returned value (-- r_2nd* r t cleanup)
1025 * load args (-- args... r_2nd* r t cleanup)
1026 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r_2nd* r)
1027 * GOTO DONE
1028 * CATCH: (-- t)
1029 * DUP (-- t t)
1030 * FINALLY_EXCEPTIONAL: (-- t t)
1031 * load cleanup (-- cleanup t t)
1032 * SWAP (-- t cleanup t)
1033 * load default for r (-- r_2nd* r t cleanup t)
1034 * load args (-- args... r_2nd* r t cleanup t)
1035 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r_2nd* r t)
1036 * POP/POP2* (-- t)
1037 * ATHROW
1038 * DONE: (-- r)
1039 * }</pre></blockquote>
1040 * * = depends on whether the return type takes up 2 stack slots.
1041 */
1042 private Name emitTryFinally(CodeBuilder cob, int pos) {
1043 Name args = lambdaForm.names[pos];
1044 Name invoker = lambdaForm.names[pos+1];
1045 Name result = lambdaForm.names[pos+2];
1046
1047 Label lFrom = cob.newLabel();
1048 Label lTo = cob.newLabel();
1049 Label lCatch = cob.newLabel();
1050 Label lDone = cob.newLabel();
1051
1052 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1053 BasicType basicReturnType = BasicType.basicType(returnType);
1054 boolean isNonVoid = returnType != void.class;
1055
1056 MethodType type = args.function.resolvedHandle().type()
1057 .dropParameterTypes(0,1)
1058 .changeReturnType(returnType);
1059 MethodType cleanupType = type.insertParameterTypes(0, Throwable.class);
1060 if (isNonVoid) {
1061 cleanupType = cleanupType.insertParameterTypes(1, returnType);
1062 }
1063 MethodTypeDesc cleanupDesc = methodDesc(cleanupType.basicType());
1064
1065 // exception handler table
1066 cob.exceptionCatch(lFrom, lTo, lCatch, CD_Throwable);
1067
1068 // TRY:
1069 cob.labelBinding(lFrom);
1070 emitPushArgument(cob, invoker, 0); // load target
1071 emitPushArguments(cob, args, 1); // load args (skip 0: method handle)
1072 cob.invokevirtual(CD_MethodHandle, "invokeBasic", methodDesc(type.basicType()))
1073 .labelBinding(lTo);
1074
1075 // FINALLY_NORMAL:
1076 int index = extendLocalsMap(new Class<?>[]{ returnType });
1077 if (isNonVoid) {
1078 emitStoreInsn(cob, basicReturnType.basicTypeKind(), index);
1079 }
1080 emitPushArgument(cob, invoker, 1); // load cleanup
1081 cob.aconst_null();
1082 if (isNonVoid) {
1083 emitLoadInsn(cob, basicReturnType.basicTypeKind(), index);
1084 }
1085 emitPushArguments(cob, args, 1); // load args (skip 0: method handle)
1086 cob.invokevirtual(CD_MethodHandle, "invokeBasic", cleanupDesc)
1087 .goto_w(lDone)
1088 // CATCH:
1089 .labelBinding(lCatch)
1090 .dup();
1091
1092 // FINALLY_EXCEPTIONAL:
1093 emitPushArgument(cob, invoker, 1); // load cleanup
1094 cob.swap();
1095 if (isNonVoid) {
1096 emitZero(cob, BasicType.basicType(returnType)); // load default for result
1097 }
1098 emitPushArguments(cob, args, 1); // load args (skip 0: method handle)
1099 cob.invokevirtual(CD_MethodHandle, "invokeBasic", cleanupDesc);
1100 if (isNonVoid) {
1101 emitPopInsn(cob, basicReturnType);
1102 }
1103 cob.athrow()
1104 // DONE:
1105 .labelBinding(lDone);
1106
1107 return result;
1108 }
1109
1110 private void emitPopInsn(CodeBuilder cob, BasicType type) {
1111 switch (type) {
1112 case I_TYPE, F_TYPE, L_TYPE -> cob.pop();
1113 case J_TYPE, D_TYPE -> cob.pop2();
1114 default -> throw new InternalError("unknown type: " + type);
1115 }
1116 }
1117
1118 private Name emitTableSwitch(CodeBuilder cob, int pos, int numCases) {
1119 Name args = lambdaForm.names[pos];
1120 Name invoker = lambdaForm.names[pos + 1];
1121 Name result = lambdaForm.names[pos + 2];
1122
1123 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1124 MethodType caseType = args.function.resolvedHandle().type()
1125 .dropParameterTypes(0, 1) // drop collector
1126 .changeReturnType(returnType);
1127 MethodTypeDesc caseDescriptor = methodDesc(caseType.basicType());
1128
1129 emitPushArgument(cob, invoker, 2); // push cases
1130 cob.getfield(CD_CasesHolder, "cases", CD_MethodHandle_array);
1131 int casesLocal = extendLocalsMap(new Class<?>[] { MethodHandle[].class });
1132 emitStoreInsn(cob, TypeKind.REFERENCE, casesLocal);
1133
1134 Label endLabel = cob.newLabel();
1135 Label defaultLabel = cob.newLabel();
1136 List<SwitchCase> cases = new ArrayList<>(numCases);
1137 for (int i = 0; i < numCases; i++) {
1138 cases.add(SwitchCase.of(i, cob.newLabel()));
1139 }
1140
1141 emitPushArgument(cob, invoker, 0); // push switch input
1142 cob.tableswitch(0, numCases - 1, defaultLabel, cases)
1143 .labelBinding(defaultLabel);
1144 emitPushArgument(cob, invoker, 1); // push default handle
1145 emitPushArguments(cob, args, 1); // again, skip collector
1146 cob.invokevirtual(CD_MethodHandle, "invokeBasic", caseDescriptor)
1147 .goto_(endLabel);
1148
1149 for (int i = 0; i < numCases; i++) {
1150 cob.labelBinding(cases.get(i).target());
1151 // Load the particular case:
1152 emitLoadInsn(cob, TypeKind.REFERENCE, casesLocal);
1153 cob.loadConstant(i)
1154 .aaload();
1155
1156 // invoke it:
1157 emitPushArguments(cob, args, 1); // again, skip collector
1158 cob.invokevirtual(CD_MethodHandle, "invokeBasic", caseDescriptor)
1159 .goto_(endLabel);
1160 }
1161
1162 cob.labelBinding(endLabel);
1163
1164 return result;
1165 }
1166
1167 /**
1168 * Emit bytecode for the loop idiom.
1169 * <p>
1170 * The pattern looks like (Cf. MethodHandleImpl.loop):
1171 * <blockquote><pre>{@code
1172 * // a0: BMH
1173 * // a1: LoopClauses (containing an array of arrays: inits, steps, preds, finis)
1174 * // a2: box, a3: unbox
1175 * // a4 (and following): arguments
1176 * loop=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L)=>{
1177 * t5:L=MethodHandle.invokeBasic(a2:L,a4:L); // box the arguments into an Object[]
1178 * t6:L=MethodHandleImpl.loop(bt:L,a1:L,t5:L); // call the loop executor (with supplied types in bt)
1179 * t7:L=MethodHandle.invokeBasic(a3:L,t6:L);t7:L} // unbox the result; return the result
1180 * }</pre></blockquote>
1181 * <p>
1182 * It is compiled into bytecode equivalent to the code seen in {@link MethodHandleImpl#loop(BasicType[],
1183 * MethodHandleImpl.LoopClauses, Object...)}, with the difference that no arrays
1184 * will be used for local state storage. Instead, the local state will be mapped to actual stack slots.
1185 * <p>
1186 * Bytecode generation applies an unrolling scheme to enable better bytecode generation regarding local state type
1187 * handling. The generated bytecode will have the following form ({@code void} types are ignored for convenience).
1188 * Assume there are {@code C} clauses in the loop.
1189 * <blockquote><pre>{@code
1190 * PREINIT: ALOAD_1
1191 * CHECKCAST LoopClauses
1192 * GETFIELD LoopClauses.clauses
1193 * ASTORE clauseDataIndex // place the clauses 2-dimensional array on the stack
1194 * INIT: (INIT_SEQ for clause 1)
1195 * ...
1196 * (INIT_SEQ for clause C)
1197 * LOOP: (LOOP_SEQ for clause 1)
1198 * ...
1199 * (LOOP_SEQ for clause C)
1200 * GOTO LOOP
1201 * DONE: ...
1202 * }</pre></blockquote>
1203 * <p>
1204 * The {@code INIT_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has
1205 * the following shape. Assume slot {@code vx} is used to hold the state for clause {@code x}.
1206 * <blockquote><pre>{@code
1207 * INIT_SEQ_x: ALOAD clauseDataIndex
1208 * ICONST_0
1209 * AALOAD // load the inits array
1210 * ICONST x
1211 * AALOAD // load the init handle for clause x
1212 * load args
1213 * INVOKEVIRTUAL MethodHandle.invokeBasic
1214 * store vx
1215 * }</pre></blockquote>
1216 * <p>
1217 * The {@code LOOP_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has
1218 * the following shape. Again, assume slot {@code vx} is used to hold the state for clause {@code x}.
1219 * <blockquote><pre>{@code
1220 * LOOP_SEQ_x: ALOAD clauseDataIndex
1221 * ICONST_1
1222 * AALOAD // load the steps array
1223 * ICONST x
1224 * AALOAD // load the step handle for clause x
1225 * load locals
1226 * load args
1227 * INVOKEVIRTUAL MethodHandle.invokeBasic
1228 * store vx
1229 * ALOAD clauseDataIndex
1230 * ICONST_2
1231 * AALOAD // load the preds array
1232 * ICONST x
1233 * AALOAD // load the pred handle for clause x
1234 * load locals
1235 * load args
1236 * INVOKEVIRTUAL MethodHandle.invokeBasic
1237 * IFNE LOOP_SEQ_x+1 // predicate returned false -> jump to next clause
1238 * ALOAD clauseDataIndex
1239 * ICONST_3
1240 * AALOAD // load the finis array
1241 * ICONST x
1242 * AALOAD // load the fini handle for clause x
1243 * load locals
1244 * load args
1245 * INVOKEVIRTUAL MethodHandle.invokeBasic
1246 * GOTO DONE // jump beyond end of clauses to return from loop
1247 * }</pre></blockquote>
1248 */
1249 private Name emitLoop(CodeBuilder cob, int pos) {
1250 Name args = lambdaForm.names[pos];
1251 Name invoker = lambdaForm.names[pos+1];
1252 Name result = lambdaForm.names[pos+2];
1253
1254 // extract clause and loop-local state types
1255 // find the type info in the loop invocation
1256 BasicType[] loopClauseTypes = (BasicType[]) invoker.arguments[0];
1257 Class<?>[] loopLocalStateTypes = Stream.of(loopClauseTypes)
1258 .filter(bt -> bt != BasicType.V_TYPE)
1259 .map(BasicType::basicTypeClass).toArray(Class<?>[]::new);
1260 Class<?>[] localTypes = new Class<?>[loopLocalStateTypes.length + 1];
1261 localTypes[0] = MethodHandleImpl.LoopClauses.class;
1262 System.arraycopy(loopLocalStateTypes, 0, localTypes, 1, loopLocalStateTypes.length);
1263
1264 final int clauseDataIndex = extendLocalsMap(localTypes);
1265 final int firstLoopStateIndex = clauseDataIndex + 1;
1266
1267 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1268 MethodType loopType = args.function.resolvedHandle().type()
1269 .dropParameterTypes(0,1)
1270 .changeReturnType(returnType);
1271 MethodType loopHandleType = loopType.insertParameterTypes(0, loopLocalStateTypes);
1272 MethodType predType = loopHandleType.changeReturnType(boolean.class);
1273 MethodType finiType = loopHandleType;
1274
1275 final int nClauses = loopClauseTypes.length;
1276
1277 // indices to invoker arguments to load method handle arrays
1278 final int inits = 1;
1279 final int steps = 2;
1280 final int preds = 3;
1281 final int finis = 4;
1282
1283 Label lLoop = cob.newLabel();
1284 Label lDone = cob.newLabel();
1285 Label lNext;
1286
1287 // PREINIT:
1288 emitPushArgument(cob, MethodHandleImpl.LoopClauses.class, invoker.arguments[1]);
1289 cob.getfield(CD_LoopClauses, "clauses", CD_MethodHandle_array2);
1290 emitStoreInsn(cob, TypeKind.REFERENCE, clauseDataIndex);
1291
1292 // INIT:
1293 for (int c = 0, state = 0; c < nClauses; ++c) {
1294 MethodType cInitType = loopType.changeReturnType(loopClauseTypes[c].basicTypeClass());
1295 emitLoopHandleInvoke(cob, invoker, inits, c, args, false, cInitType, loopLocalStateTypes, clauseDataIndex,
1296 firstLoopStateIndex);
1297 if (cInitType.returnType() != void.class) {
1298 emitStoreInsn(cob, BasicType.basicType(cInitType.returnType()).basicTypeKind(), firstLoopStateIndex + state);
1299 ++state;
1300 }
1301 }
1302
1303 // LOOP:
1304 cob.labelBinding(lLoop);
1305
1306 for (int c = 0, state = 0; c < nClauses; ++c) {
1307 lNext = cob.newLabel();
1308
1309 MethodType stepType = loopHandleType.changeReturnType(loopClauseTypes[c].basicTypeClass());
1310 boolean isVoid = stepType.returnType() == void.class;
1311
1312 // invoke loop step
1313 emitLoopHandleInvoke(cob, invoker, steps, c, args, true, stepType, loopLocalStateTypes, clauseDataIndex,
1314 firstLoopStateIndex);
1315 if (!isVoid) {
1316 emitStoreInsn(cob, BasicType.basicType(stepType.returnType()).basicTypeKind(), firstLoopStateIndex + state);
1317 ++state;
1318 }
1319
1320 // invoke loop predicate
1321 emitLoopHandleInvoke(cob, invoker, preds, c, args, true, predType, loopLocalStateTypes, clauseDataIndex,
1322 firstLoopStateIndex);
1323 cob.ifne(lNext);
1324
1325 // invoke fini
1326 emitLoopHandleInvoke(cob, invoker, finis, c, args, true, finiType, loopLocalStateTypes, clauseDataIndex,
1327 firstLoopStateIndex);
1328 cob.goto_w(lDone)
1329 // this is the beginning of the next loop clause
1330 .labelBinding(lNext);
1331 }
1332
1333 cob.goto_w(lLoop)
1334 // DONE:
1335 .labelBinding(lDone);
1336
1337 return result;
1338 }
1339
1340 private int extendLocalsMap(Class<?>[] types) {
1341 int firstSlot = localsMap.length - 1;
1342 localsMap = Arrays.copyOf(localsMap, localsMap.length + types.length);
1343 localClasses = Arrays.copyOf(localClasses, localClasses.length + types.length);
1344 System.arraycopy(types, 0, localClasses, firstSlot, types.length);
1345 int index = localsMap[firstSlot - 1] + 1;
1346 int lastSlots = 0;
1347 for (int i = 0; i < types.length; ++i) {
1348 localsMap[firstSlot + i] = index;
1349 lastSlots = BasicType.basicType(localClasses[firstSlot + i]).basicTypeSlots();
1350 index += lastSlots;
1351 }
1352 localsMap[localsMap.length - 1] = index - lastSlots;
1353 return firstSlot;
1354 }
1355
1356 private void emitLoopHandleInvoke(CodeBuilder cob, Name holder, int handles, int clause, Name args, boolean pushLocalState,
1357 MethodType type, Class<?>[] loopLocalStateTypes, int clauseDataSlot,
1358 int firstLoopStateSlot) {
1359 // load handle for clause
1360 emitPushClauseArray(cob, clauseDataSlot, handles);
1361 cob.loadConstant(clause)
1362 .aaload();
1363 // load loop state (preceding the other arguments)
1364 if (pushLocalState) {
1365 for (int s = 0; s < loopLocalStateTypes.length; ++s) {
1366 emitLoadInsn(cob, BasicType.basicType(loopLocalStateTypes[s]).basicTypeKind(), firstLoopStateSlot + s);
1367 }
1368 }
1369 // load loop args (skip 0: method handle)
1370 emitPushArguments(cob, args, 1);
1371 cob.invokevirtual(CD_MethodHandle, "invokeBasic", methodDesc(type));
1372 }
1373
1374 private void emitPushClauseArray(CodeBuilder cob, int clauseDataSlot, int which) {
1375 emitLoadInsn(cob, TypeKind.REFERENCE, clauseDataSlot);
1376 cob.loadConstant(which - 1)
1377 .aaload();
1378 }
1379
1380 private void emitZero(CodeBuilder cob, BasicType type) {
1381 switch (type) {
1382 case I_TYPE -> cob.iconst_0();
1383 case J_TYPE -> cob.lconst_0();
1384 case F_TYPE -> cob.fconst_0();
1385 case D_TYPE -> cob.dconst_0();
1386 case L_TYPE -> cob.aconst_null();
1387 default -> throw new InternalError("unknown type: " + type);
1388 };
1389 }
1390
1391 private void emitPushArguments(CodeBuilder cob, Name args, int start) {
1392 MethodType type = args.function.methodType();
1393 for (int i = start; i < args.arguments.length; i++) {
1394 emitPushArgument(cob, type.parameterType(i), args.arguments[i]);
1395 }
1396 }
1397
1398 private void emitPushArgument(CodeBuilder cob, Name name, int paramIndex) {
1399 Object arg = name.arguments[paramIndex];
1400 Class<?> ptype = name.function.methodType().parameterType(paramIndex);
1401 emitPushArgument(cob, ptype, arg);
1402 }
1403
1404 private void emitPushArgument(CodeBuilder cob, Class<?> ptype, Object arg) {
1405 BasicType bptype = basicType(ptype);
1406 if (arg instanceof Name n) {
1407 emitLoadInsn(cob, n.type.basicTypeKind(), n.index());
1408 emitImplicitConversion(cob, n.type, ptype, n);
1409 } else if ((arg == null || arg instanceof String) && bptype == L_TYPE) {
1410 cob.loadConstant((ConstantDesc)arg);
1411 } else {
1412 if (Wrapper.isWrapperType(arg.getClass()) && bptype != L_TYPE) {
1413 cob.loadConstant((ConstantDesc)arg);
1414 } else {
1415 cob.getstatic(classData(cob, arg, CD_Object));
1416 emitImplicitConversion(cob, L_TYPE, ptype, arg);
1417 }
1418 }
1419 }
1420
1421 /**
1422 * Store the name to its local, if necessary.
1423 */
1424 private void emitStoreResult(CodeBuilder cob, Name name) {
1425 if (name != null && name.type != V_TYPE) {
1426 // non-void: actually assign
1427 emitStoreInsn(cob, name.type.basicTypeKind(), name.index());
1428 }
1429 }
1430
1431 /**
1432 * Emits a return statement from a LF invoker. If required, the result type is cast to the correct return type.
1433 */
1434 private void emitReturn(CodeBuilder cob, Name onStack) {
1435 // return statement
1436 Class<?> rclass = invokerType.returnType();
1437 BasicType rtype = lambdaForm.returnType();
1438 assert(rtype == basicType(rclass)); // must agree
1439 if (rtype == V_TYPE) {
1440 // void
1441 cob.return_();
1442 // it doesn't matter what rclass is; the JVM will discard any value
1443 } else {
1444 LambdaForm.Name rn = lambdaForm.names[lambdaForm.result];
1445
1446 // put return value on the stack if it is not already there
1447 if (rn != onStack) {
1448 emitLoadInsn(cob, rtype.basicTypeKind(), lambdaForm.result);
1449 }
1450
1451 emitImplicitConversion(cob, rtype, rclass, rn);
1452
1453 // generate actual return statement
1454 cob.return_(rtype.basicTypeKind());
1455 }
1456 }
1457
1458 /**
1459 * Emit a type conversion bytecode casting from "from" to "to".
1460 */
1461 private void emitPrimCast(CodeBuilder cob, TypeKind from, TypeKind to) {
1462 // Here's how.
1463 // - indicates forbidden
1464 // <-> indicates implicit
1465 // to ----> boolean byte short char int long float double
1466 // from boolean <-> - - - - - - -
1467 // byte - <-> i2s i2c <-> i2l i2f i2d
1468 // short - i2b <-> i2c <-> i2l i2f i2d
1469 // char - i2b i2s <-> <-> i2l i2f i2d
1470 // int - i2b i2s i2c <-> i2l i2f i2d
1471 // long - l2i,i2b l2i,i2s l2i,i2c l2i <-> l2f l2d
1472 // float - f2i,i2b f2i,i2s f2i,i2c f2i f2l <-> f2d
1473 // double - d2i,i2b d2i,i2s d2i,i2c d2i d2l d2f <->
1474 if (from != to && from != TypeKind.BOOLEAN) try {
1475 cob.conversion(from, to);
1476 } catch (IllegalArgumentException e) {
1477 throw new IllegalStateException("unhandled prim cast: " + from + "2" + to);
1478 }
1479 }
1480
1481 /**
1482 * Generate bytecode for a LambdaForm.vmentry which calls interpretWithArguments.
1483 */
1484 static MemberName generateLambdaFormInterpreterEntryPoint(MethodType mt) {
1485 assert(isValidSignature(basicTypeSignature(mt)));
1486 String name = "interpret_"+basicTypeChar(mt.returnType());
1487 MethodType type = mt; // includes leading argument
1488 type = type.changeParameterType(0, MethodHandle.class);
1489 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("LFI", name, type);
1490 return g.loadMethod(g.generateLambdaFormInterpreterEntryPointBytes());
1491 }
1492
1493 private byte[] generateLambdaFormInterpreterEntryPointBytes() {
1494 final byte[] classFile = classFileSetup(new Consumer<>() {
1495 @Override
1496 public void accept(ClassBuilder clb) {
1497 methodSetup(clb, new Consumer<>() {
1498 @Override
1499 public void accept(MethodBuilder mb) {
1500
1501 mb.with(RuntimeVisibleAnnotationsAttribute.of(List.of(
1502 HIDDEN, // Suppress this method in backtraces displayed to the user.
1503 DONTINLINE // Don't inline the interpreter entry.
1504 )));
1505
1506 mb.withCode(new Consumer<>() {
1507 @Override
1508 public void accept(CodeBuilder cob) {
1509 // create parameter array
1510 cob.loadConstant(invokerType.parameterCount())
1511 .anewarray(CD_Object);
1512
1513 // fill parameter array
1514 for (int i = 0; i < invokerType.parameterCount(); i++) {
1515 Class<?> ptype = invokerType.parameterType(i);
1516 cob.dup()
1517 .loadConstant(i);
1518 emitLoadInsn(cob, basicType(ptype).basicTypeKind(), i);
1519 // box if primitive type
1520 if (ptype.isPrimitive()) {
1521 emitBoxing(cob, TypeKind.from(ptype));
1522 }
1523 cob.aastore();
1524 }
1525 // invoke
1526 cob.aload(0)
1527 .getfield(CD_MethodHandle, "form", CD_LambdaForm)
1528 .swap() // swap form and array; avoid local variable
1529 .invokevirtual(CD_LambdaForm, "interpretWithArguments", MethodTypeDescImpl.ofValidated(CD_Object, CD_Object_array));
1530
1531 // maybe unbox
1532 Class<?> rtype = invokerType.returnType();
1533 TypeKind rtypeK = TypeKind.from(rtype);
1534 if (rtype.isPrimitive() && rtype != void.class) {
1535 emitUnboxing(cob, rtypeK);
1536 }
1537
1538 // return statement
1539 cob.return_(rtypeK);
1540 }
1541 });
1542 }
1543 });
1544 clinit(clb, classEntry, classData);
1545 bogusMethod(clb, invokerType);
1546 }
1547 });
1548 return classFile;
1549 }
1550
1551 /**
1552 * Generate bytecode for a NamedFunction invoker.
1553 */
1554 static MemberName generateNamedFunctionInvoker(MethodTypeForm typeForm) {
1555 MethodType invokerType = NamedFunction.INVOKER_METHOD_TYPE;
1556 String invokerName = "invoke_" + shortenSignature(basicTypeSignature(typeForm.erasedType()));
1557 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("NFI", invokerName, invokerType);
1558 return g.loadMethod(g.generateNamedFunctionInvokerImpl(typeForm));
1559 }
1560
1561 private byte[] generateNamedFunctionInvokerImpl(MethodTypeForm typeForm) {
1562 MethodType dstType = typeForm.erasedType();
1563 final byte[] classFile = classFileSetup(new Consumer<>() {
1564 @Override
1565 public void accept(ClassBuilder clb) {
1566 methodSetup(clb, new Consumer<>() {
1567 @Override
1568 public void accept(MethodBuilder mb) {
1569
1570 mb.with(RuntimeVisibleAnnotationsAttribute.of(List.of(
1571 HIDDEN, // Suppress this method in backtraces displayed to the user.
1572 FORCEINLINE // Force inlining of this invoker method.
1573 )));
1574
1575 mb.withCode(new Consumer<>() {
1576 @Override
1577 public void accept(CodeBuilder cob) {
1578 // Load receiver
1579 cob.aload(0);
1580
1581 // Load arguments from array
1582 for (int i = 0; i < dstType.parameterCount(); i++) {
1583 cob.aload(1)
1584 .loadConstant(i)
1585 .aaload();
1586
1587 // Maybe unbox
1588 Class<?> dptype = dstType.parameterType(i);
1589 if (dptype.isPrimitive()) {
1590 TypeKind dstTK = TypeKind.from(dptype);
1591 TypeKind srcTK = dstTK.asLoadable();
1592 emitUnboxing(cob, srcTK);
1593 emitPrimCast(cob, srcTK, dstTK);
1594 }
1595 }
1596
1597 // Invoke
1598 MethodTypeDesc targetDesc = methodDesc(dstType.basicType());
1599 cob.invokevirtual(CD_MethodHandle, "invokeBasic", targetDesc);
1600
1601 // Box primitive types
1602 Class<?> rtype = dstType.returnType();
1603 if (rtype != void.class && rtype.isPrimitive()) {
1604 TypeKind srcTK = TypeKind.from(rtype);
1605 TypeKind dstTK = srcTK.asLoadable();
1606 // boolean casts not allowed
1607 emitPrimCast(cob, srcTK, dstTK);
1608 emitBoxing(cob, dstTK);
1609 }
1610
1611 // If the return type is void we return a null reference.
1612 if (rtype == void.class) {
1613 cob.aconst_null();
1614 }
1615 cob.areturn(); // NOTE: NamedFunction invokers always return a reference value.
1616 }
1617 });
1618 }
1619 });
1620 clinit(clb, classEntry, classData);
1621 bogusMethod(clb, dstType);
1622 }
1623 });
1624 return classFile;
1625 }
1626
1627 /**
1628 * Emit a bogus method that just loads some string constants. This is to get the constants into the constant pool
1629 * for debugging purposes.
1630 */
1631 private void bogusMethod(ClassBuilder clb, Object os) {
1632 if (dumper().isEnabled()) {
1633 clb.withMethodBody("dummy", MTD_void, ACC_STATIC, new Consumer<>() {
1634 @Override
1635 public void accept(CodeBuilder cob) {
1636 cob.ldc(os.toString())
1637 .pop()
1638 .return_();
1639 }
1640 });
1641 }
1642 }
1643
1644 static ClassDesc classDesc(Class<?> cls) {
1645 // assert(VerifyAccess.isTypeVisible(cls, Object.class)) : cls.getName();
1646 return cls == MethodHandle.class ? CD_MethodHandle
1647 : cls == DirectMethodHandle.class ? CD_DirectMethodHandle
1648 : cls == Object.class ? CD_Object
1649 : cls == MemberName.class ? CD_MemberName
1650 : cls == MethodType.class ? CD_MethodType
1651 : cls.isPrimitive() ? Wrapper.forPrimitiveType(cls).basicClassDescriptor()
1652 : ReferenceClassDescImpl.ofValidated(cls.descriptorString());
1653 }
1654
1655 static MethodTypeDesc methodDesc(MethodType mt) {
1656 var params = new ClassDesc[mt.parameterCount()];
1657 for (int i = 0; i < params.length; i++) {
1658 params[i] = classDesc(mt.parameterType(i));
1659 }
1660 return MethodTypeDescImpl.ofValidated(classDesc(mt.returnType()), params);
1661 }
1662 }