1 /*
2 * Copyright (c) 2012, 2023, 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.instruction.SwitchCase;
36 import java.lang.constant.ClassDesc;
37 import java.lang.constant.ConstantDesc;
38 import java.lang.constant.MethodTypeDesc;
39 import java.lang.invoke.LambdaForm.BasicType;
40 import java.lang.invoke.LambdaForm.Name;
41 import java.lang.invoke.LambdaForm.NamedFunction;
42 import java.lang.reflect.Modifier;
43 import java.util.ArrayList;
44 import java.util.Arrays;
45 import java.util.HashMap;
46 import java.util.List;
47 import java.util.Set;
48 import java.util.function.Consumer;
49 import java.util.stream.Stream;
50 import jdk.internal.constant.MethodTypeDescImpl;
51 import jdk.internal.constant.ReferenceClassDescImpl;
52
53 import static java.lang.classfile.ClassFile.*;
54 import static java.lang.constant.ConstantDescs.*;
55 import static java.lang.invoke.LambdaForm.*;
56 import static java.lang.invoke.LambdaForm.BasicType.*;
57 import static java.lang.invoke.MethodHandleNatives.Constants.*;
58 import static java.lang.invoke.MethodHandleStatics.*;
59 import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
60
61 /**
62 * Code generation backend for LambdaForm.
63 * <p>
64 * @author John Rose, JSR 292 EG
65 */
66 class InvokerBytecodeGenerator {
67 /** Define class names for convenience. */
68 private static final ClassDesc CD_CasesHolder = ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/MethodHandleImpl$CasesHolder;");
69 private static final ClassDesc CD_DirectMethodHandle = ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/DirectMethodHandle;");
70 private static final ClassDesc CD_MethodHandleImpl = ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/MethodHandleImpl;");
71 private static final ClassDesc CD_LambdaForm = ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/LambdaForm;");
72 private static final ClassDesc CD_LambdaForm_Name = ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/LambdaForm$Name;");
73 private static final ClassDesc CD_LoopClauses = ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/MethodHandleImpl$LoopClauses;");
74 private static final ClassDesc CD_Object_array = ReferenceClassDescImpl.ofValidated("[Ljava/lang/Object;");
75 private static final ClassDesc CD_MethodHandle_array = ReferenceClassDescImpl.ofValidated("[Ljava/lang/invoke/MethodHandle;");
76 private static final ClassDesc CD_MethodHandle_array2 = ReferenceClassDescImpl.ofValidated("[[Ljava/lang/invoke/MethodHandle;");
77
78 private static final MethodTypeDesc MTD_boolean_Object = MethodTypeDescImpl.ofValidated(CD_boolean, CD_Object);
79 private static final MethodTypeDesc MTD_Object_int = MethodTypeDescImpl.ofValidated(CD_Object, CD_int);
80 private static final MethodTypeDesc MTD_Object_Class = MethodTypeDescImpl.ofValidated(CD_Object, CD_Class);
81 private static final MethodTypeDesc MTD_Object_Object = MethodTypeDescImpl.ofValidated(CD_Object, CD_Object);
82
83 private static final String CLASS_PREFIX = "java/lang/invoke/LambdaForm$";
84 private static final String SOURCE_PREFIX = "LambdaForm$";
85
86 // Static builders to avoid lambdas
87 private static final Consumer<FieldBuilder> STATIC_FINAL_FIELD = new Consumer<FieldBuilder>() {
88 @Override
89 public void accept(FieldBuilder fb) {
90 fb.withFlags(ACC_STATIC | ACC_FINAL);
91 }
92 };
93
94 record MethodBody(Consumer<CodeBuilder> code) implements Consumer<MethodBuilder> {
95 @Override
96 public void accept(MethodBuilder mb) {
97 mb.withCode(code);
98 }
99 };
100
101 /** Name of its super class*/
102 static final ClassDesc INVOKER_SUPER_DESC = CD_Object;
103
104 /** Name of new class */
105 private final String name;
106 private final String className;
107 private final ClassDesc classDesc;
108
109 private final LambdaForm lambdaForm;
110 private final String invokerName;
111 private final MethodType invokerType;
112
113 /** Info about local variables in compiled lambda form */
114 private int[] localsMap; // index
115 private Class<?>[] localClasses; // type
116
117 private final List<ClassData> classData = new ArrayList<>();
118
119 private static final MemberName.Factory MEMBERNAME_FACTORY = MemberName.getFactory();
120 private static final Class<?> HOST_CLASS = LambdaForm.class;
121 private static final MethodHandles.Lookup LOOKUP = lookup();
122
123 private static MethodHandles.Lookup lookup() {
124 try {
125 return MethodHandles.privateLookupIn(HOST_CLASS, IMPL_LOOKUP);
126 } catch (IllegalAccessException e) {
127 throw newInternalError(e);
128 }
129 }
130
131 /** Main constructor; other constructors delegate to this one. */
132 private InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize,
133 String name, String invokerName, MethodType invokerType) {
134 int p = invokerName.indexOf('.');
135 if (p > -1) {
136 name = invokerName.substring(0, p);
137 invokerName = invokerName.substring(p + 1);
138 }
139 if (dumper().isEnabled()) {
140 name = makeDumpableClassName(name);
141 }
142 this.name = name;
143 this.className = CLASS_PREFIX + name;
144 this.classDesc = ClassDesc.ofInternalName(className);
145 this.lambdaForm = lambdaForm;
146 this.invokerName = invokerName;
147 this.invokerType = invokerType;
148 this.localsMap = new int[localsMapSize+1]; // last entry of localsMap is count of allocated local slots
149 this.localClasses = new Class<?>[localsMapSize+1];
150 }
151
152 /** For generating LambdaForm interpreter entry points. */
153 private InvokerBytecodeGenerator(String name, String invokerName, MethodType invokerType) {
154 this(null, invokerType.parameterCount(),
155 name, invokerName, invokerType);
156 MethodType mt = invokerType.erase();
157 // Create an array to map name indexes to locals indexes.
158 localsMap[0] = 0; // localsMap has at least one element
159 for (int i = 1, index = 0; i < localsMap.length; i++) {
160 Wrapper w = Wrapper.forBasicType(mt.parameterType(i - 1));
161 index += w.stackSlots();
162 localsMap[i] = index;
163 }
164 }
165
166 /** For generating customized code for a single LambdaForm. */
167 private InvokerBytecodeGenerator(String name, LambdaForm form, MethodType invokerType) {
168 this(name, form.lambdaName(), form, invokerType);
169 }
170
171 /** For generating customized code for a single LambdaForm. */
172 InvokerBytecodeGenerator(String name, String invokerName,
173 LambdaForm form, MethodType invokerType) {
174 this(form, form.names.length,
175 name, invokerName, invokerType);
176 // Create an array to map name indexes to locals indexes.
177 Name[] names = form.names;
178 for (int i = 0, index = 0; i < localsMap.length; i++) {
179 localsMap[i] = index;
180 if (i < names.length) {
181 BasicType type = names[i].type();
182 index += type.basicTypeSlots();
183 }
184 }
185 }
186
187 /** instance counters for dumped classes */
188 private static final HashMap<String,Integer> DUMP_CLASS_FILES_COUNTERS =
189 dumper().isEnabled() ? new HashMap<>(): null;
190
191 private static String makeDumpableClassName(String className) {
192 Integer ctr;
193 synchronized (DUMP_CLASS_FILES_COUNTERS) {
194 ctr = DUMP_CLASS_FILES_COUNTERS.get(className);
195 if (ctr == null) ctr = 0;
196 DUMP_CLASS_FILES_COUNTERS.put(className, ctr+1);
197 }
198 String sfx = ctr.toString();
199 while (sfx.length() < 3)
200 sfx = "0" + sfx;
201 className += sfx;
202 return className;
203 }
204
205 static class ClassData {
206 final String name;
207 final ClassDesc desc;
208 final Object value;
209
210 ClassData(String name, ClassDesc desc, Object value) {
211 this.name = name;
212 this.desc = desc;
213 this.value = value;
214 }
215
216 public String name() { return name; }
217 public String toString() {
218 return name + ",value="+value;
219 }
220 }
221
222 String classData(Object arg) {
223 ClassDesc desc;
224 if (arg instanceof Class) {
225 desc = CD_Class;
226 } else if (arg instanceof MethodHandle) {
227 desc = CD_MethodHandle;
228 } else if (arg instanceof LambdaForm) {
229 desc = CD_LambdaForm;
230 } else {
231 desc = CD_Object;
232 }
233
234 // unique static variable name
235 String name;
236 if (dumper().isEnabled()) {
237 Class<?> c = arg.getClass();
238 while (c.isArray()) {
239 c = c.getComponentType();
240 }
241 name = "_DATA_" + c.getSimpleName() + "_" + classData.size();
242 } else {
243 name = "_D_" + classData.size();
244 }
245 ClassData cd = new ClassData(name, desc, arg);
246 classData.add(cd);
247 return name;
248 }
249
250 /**
251 * Extract the MemberName of a newly-defined method.
252 */
253 private MemberName loadMethod(byte[] classFile) {
254 Class<?> invokerClass = LOOKUP.makeHiddenClassDefiner(className, classFile, Set.of(), dumper())
255 .defineClass(true, classDataValues());
256 return resolveInvokerMember(invokerClass, invokerName, invokerType);
257 }
258
259 private static MemberName resolveInvokerMember(Class<?> invokerClass, String name, MethodType type) {
260 MemberName member = new MemberName(invokerClass, name, type, REF_invokeStatic);
261 try {
262 member = MEMBERNAME_FACTORY.resolveOrFail(REF_invokeStatic, member,
263 HOST_CLASS, LM_TRUSTED,
264 ReflectiveOperationException.class);
265 } catch (ReflectiveOperationException e) {
266 throw newInternalError(e);
267 }
268 return member;
269 }
270
271 /**
272 * Set up class file generation.
273 */
274 private byte[] classFileSetup(Consumer<? super ClassBuilder> config) {
275 try {
276 return ClassFile.of().build(classDesc, new Consumer<>() {
277 @Override
278 public void accept(ClassBuilder clb) {
279 clb.withFlags(ACC_FINAL | ACC_SUPER)
280 .withSuperclass(INVOKER_SUPER_DESC)
281 .with(SourceFileAttribute.of(clb.constantPool().utf8Entry(SOURCE_PREFIX + name)));
282 config.accept(clb);
283 }
284 });
285 } catch (RuntimeException e) {
286 throw new BytecodeGenerationException(e);
287 }
288 }
289
290 private void methodSetup(ClassBuilder clb, Consumer<? super MethodBuilder> config) {
291 var invokerDesc = methodDesc(invokerType);
292 clb.withMethod(invokerName, invokerDesc, ACC_STATIC, config);
293 }
294
295 /**
296 * Returns the class data object that will be passed to `Lookup.defineHiddenClassWithClassData`.
297 * The classData is loaded in the <clinit> method of the generated class.
298 * If the class data contains only one single object, this method returns that single object.
299 * If the class data contains more than one objects, this method returns a List.
300 *
301 * This method returns null if no class data.
302 */
303 private Object classDataValues() {
304 final List<ClassData> cd = classData;
305 return switch (cd.size()) {
306 case 0 -> null; // special case (classData is not used by <clinit>)
307 case 1 -> cd.get(0).value; // special case (single object)
308 case 2 -> List.of(cd.get(0).value, cd.get(1).value);
309 case 3 -> List.of(cd.get(0).value, cd.get(1).value, cd.get(2).value);
310 case 4 -> List.of(cd.get(0).value, cd.get(1).value, cd.get(2).value, cd.get(3).value);
311 default -> {
312 Object[] data = new Object[classData.size()];
313 for (int i = 0; i < classData.size(); i++) {
314 data[i] = classData.get(i).value;
315 }
316 yield List.of(data);
317 }
318 };
319 }
320
321 /*
322 * <clinit> to initialize the static final fields with the live class data
323 * LambdaForms can't use condy due to bootstrapping issue.
324 */
325 static void clinit(ClassBuilder clb, ClassDesc classDesc, List<ClassData> classData) {
326 if (classData.isEmpty())
327 return;
328
329 for (ClassData p : classData) {
330 // add the static field
331 clb.withField(p.name, p.desc, STATIC_FINAL_FIELD);
332 }
333
334 clb.withMethod(CLASS_INIT_NAME, MTD_void, ACC_STATIC, new MethodBody(new Consumer<CodeBuilder>() {
335 @Override
336 public void accept(CodeBuilder cob) {
337 cob.loadConstant(classDesc)
338 .invokestatic(CD_MethodHandles, "classData", MTD_Object_Class);
339 if (classData.size() == 1) {
340 ClassData p = classData.get(0);
341 cob.checkcast(p.desc)
342 .putstatic(classDesc, p.name, p.desc);
343 } else {
344 cob.checkcast(CD_List)
345 .astore(0);
346 int index = 0;
347 var listGet = cob.constantPool().interfaceMethodRefEntry(CD_List, "get", MTD_Object_int);
348 for (ClassData p : classData) {
349 // initialize the static field
350 cob.aload(0)
351 .loadConstant(index++)
352 .invokeinterface(listGet)
353 .checkcast(p.desc)
354 .putstatic(classDesc, p.name, p.desc);
355 }
356 }
357 cob.return_();
358 }
359 }));
360 }
361
362 private void emitLoadInsn(CodeBuilder cob, TypeKind type, int index) {
363 cob.loadLocal(type, localsMap[index]);
364 }
365
366 private void emitStoreInsn(CodeBuilder cob, TypeKind type, int index) {
367 cob.storeLocal(type, localsMap[index]);
368 }
369
370 /**
371 * Emit a boxing call.
372 *
373 * @param wrapper primitive type class to box.
374 */
375 private void emitBoxing(CodeBuilder cob, TypeKind tk) {
376 TypeConvertingMethodAdapter.box(cob, tk);
377 }
378
379 /**
380 * Emit an unboxing call (plus preceding checkcast).
381 *
382 * @param wrapper wrapper type class to unbox.
383 */
384 private void emitUnboxing(CodeBuilder cob, TypeKind target) {
385 switch (target) {
386 case BooleanType -> emitReferenceCast(cob, Boolean.class, null);
387 case CharType -> emitReferenceCast(cob, Character.class, null);
388 case ByteType, DoubleType, FloatType, IntType, LongType, ShortType ->
389 emitReferenceCast(cob, Number.class, null);
390 default -> {}
391 }
392 TypeConvertingMethodAdapter.unbox(cob, target);
393 }
394
395 /**
396 * Emit an implicit conversion for an argument which must be of the given pclass.
397 * This is usually a no-op, except when pclass is a subword type or a reference other than Object or an interface.
398 *
399 * @param ptype type of value present on stack
400 * @param pclass type of value required on stack
401 * @param arg compile-time representation of value on stack (Node, constant) or null if none
402 */
403 private void emitImplicitConversion(CodeBuilder cob, BasicType ptype, Class<?> pclass, Object arg) {
404 assert(basicType(pclass) == ptype); // boxing/unboxing handled by caller
405 if (pclass == ptype.basicTypeClass() && ptype != L_TYPE)
406 return; // nothing to do
407 switch (ptype) {
408 case L_TYPE:
409 if (VerifyType.isNullConversion(Object.class, pclass, false)) {
410 if (PROFILE_LEVEL > 0)
411 emitReferenceCast(cob, Object.class, arg);
412 return;
413 }
414 emitReferenceCast(cob, pclass, arg);
415 return;
416 case I_TYPE:
417 if (!VerifyType.isNullConversion(int.class, pclass, false))
418 emitPrimCast(cob, ptype.basicTypeKind(), TypeKind.from(pclass));
419 return;
420 }
421 throw newInternalError("bad implicit conversion: tc="+ptype+": "+pclass);
422 }
423
424 /** Update localClasses type map. Return true if the information is already present. */
425 private boolean assertStaticType(Class<?> cls, Name n) {
426 int local = n.index();
427 Class<?> aclass = localClasses[local];
428 if (aclass != null && (aclass == cls || cls.isAssignableFrom(aclass))) {
429 return true; // type info is already present
430 } else if (aclass == null || aclass.isAssignableFrom(cls)) {
431 localClasses[local] = cls; // type info can be improved
432 }
433 return false;
434 }
435
436 private void emitReferenceCast(CodeBuilder cob, Class<?> cls, Object arg) {
437 Name writeBack = null; // local to write back result
438 if (arg instanceof Name n) {
439 if (lambdaForm.useCount(n) > 1) {
440 // This guy gets used more than once.
441 writeBack = n;
442 if (assertStaticType(cls, n)) {
443 return; // this cast was already performed
444 }
445 }
446 }
447 if (isStaticallyNameable(cls)) {
448 ClassDesc sig = classDesc(cls);
449 cob.checkcast(sig);
450 } else {
451 cob.getstatic(classDesc, classData(cls), CD_Class)
452 .swap()
453 .invokevirtual(CD_Class, "cast", MTD_Object_Object);
454 if (Object[].class.isAssignableFrom(cls))
455 cob.checkcast(CD_Object_array);
456 else if (PROFILE_LEVEL > 0)
457 cob.checkcast(CD_Object);
458 }
459 if (writeBack != null) {
460 cob.dup();
461 emitStoreInsn(cob, TypeKind.ReferenceType, writeBack.index());
462 }
463 }
464
465 private static MemberName resolveFrom(String name, MethodType type, Class<?> holder) {
466 assert(!UNSAFE.shouldBeInitialized(holder)) : holder + "not initialized";
467 MemberName member = new MemberName(holder, name, type, REF_invokeStatic);
468 MemberName resolvedMember = MemberName.getFactory().resolveOrNull(REF_invokeStatic, member, holder, LM_TRUSTED);
469 traceLambdaForm(name, type, holder, resolvedMember);
470 return resolvedMember;
471 }
472
473 private static MemberName lookupPregenerated(LambdaForm form, MethodType invokerType) {
474 if (form.customized != null) {
475 // No pre-generated version for customized LF
476 return null;
477 }
478 String name = form.kind.methodName;
479 switch (form.kind) {
480 case BOUND_REINVOKER: {
481 name = name + "_" + BoundMethodHandle.speciesDataFor(form).key();
482 return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class);
483 }
484 case DELEGATE: return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class);
485 case ZERO: // fall-through
486 case IDENTITY: {
487 name = name + "_" + form.returnType().basicTypeChar();
488 return resolveFrom(name, invokerType, LambdaForm.Holder.class);
489 }
490 case EXACT_INVOKER: // fall-through
491 case EXACT_LINKER: // fall-through
492 case LINK_TO_CALL_SITE: // fall-through
493 case LINK_TO_TARGET_METHOD: // fall-through
494 case GENERIC_INVOKER: // fall-through
495 case GENERIC_LINKER: return resolveFrom(name, invokerType, Invokers.Holder.class);
496 case GET_REFERENCE: // fall-through
497 case GET_BOOLEAN: // fall-through
498 case GET_BYTE: // fall-through
499 case GET_CHAR: // fall-through
500 case GET_SHORT: // fall-through
501 case GET_INT: // fall-through
502 case GET_LONG: // fall-through
503 case GET_FLOAT: // fall-through
504 case GET_DOUBLE: // fall-through
505 case PUT_REFERENCE: // fall-through
506 case PUT_BOOLEAN: // fall-through
507 case PUT_BYTE: // fall-through
508 case PUT_CHAR: // fall-through
509 case PUT_SHORT: // fall-through
510 case PUT_INT: // fall-through
511 case PUT_LONG: // fall-through
512 case PUT_FLOAT: // fall-through
513 case PUT_DOUBLE: // fall-through
514 case DIRECT_NEW_INVOKE_SPECIAL: // fall-through
515 case DIRECT_INVOKE_INTERFACE: // fall-through
516 case DIRECT_INVOKE_SPECIAL: // fall-through
517 case DIRECT_INVOKE_SPECIAL_IFC: // fall-through
518 case DIRECT_INVOKE_STATIC: // fall-through
519 case DIRECT_INVOKE_STATIC_INIT: // fall-through
520 case DIRECT_INVOKE_VIRTUAL: return resolveFrom(name, invokerType, DirectMethodHandle.Holder.class);
521 }
522 return null;
523 }
524
525 /**
526 * Generate customized bytecode for a given LambdaForm.
527 */
528 static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) {
529 MemberName pregenerated = lookupPregenerated(form, invokerType);
530 if (pregenerated != null) return pregenerated; // pre-generated bytecode
531
532 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("MH", form, invokerType);
533 return g.loadMethod(g.generateCustomizedCodeBytes());
534 }
535
536 /** Generates code to check that actual receiver and LambdaForm matches */
537 private boolean checkActualReceiver(CodeBuilder cob) {
538 // Expects MethodHandle on the stack and actual receiver MethodHandle in slot #0
539 cob.dup()
540 .aload(0)
541 .invokestatic(CD_MethodHandleImpl, "assertSame", MethodTypeDescImpl.ofValidated(CD_void, CD_Object, CD_Object));
542 return true;
543 }
544
545 static final Annotation DONTINLINE = Annotation.of(ReferenceClassDescImpl.ofValidated("Ljdk/internal/vm/annotation/DontInline;"));
546 static final Annotation FORCEINLINE = Annotation.of(ReferenceClassDescImpl.ofValidated("Ljdk/internal/vm/annotation/ForceInline;"));
547 static final Annotation HIDDEN = Annotation.of(ReferenceClassDescImpl.ofValidated("Ljdk/internal/vm/annotation/Hidden;"));
548 static final Annotation INJECTEDPROFILE = Annotation.of(ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/InjectedProfile;"));
549 static final Annotation LF_COMPILED = Annotation.of(ReferenceClassDescImpl.ofValidated("Ljava/lang/invoke/LambdaForm$Compiled;"));
550
551 /**
552 * Generate an invoker method for the passed {@link LambdaForm}.
553 */
554 private byte[] generateCustomizedCodeBytes() {
555 final byte[] classFile = classFileSetup(new Consumer<ClassBuilder>() {
556 @Override
557 public void accept(ClassBuilder clb) {
558 addMethod(clb);
559 clinit(clb, classDesc, classData);
560 bogusMethod(clb, lambdaForm);
561 }
562 });
563 return classFile;
564 }
565
566 void addMethod(ClassBuilder clb) {
567 methodSetup(clb, new Consumer<MethodBuilder>() {
568 @Override
569 public void accept(MethodBuilder mb) {
570
571 List<Annotation> annotations = new ArrayList<>(3);
572
573 // Suppress this method in backtraces displayed to the user.
574 annotations.add(HIDDEN);
575
576 // Mark this method as a compiled LambdaForm
577 annotations.add(LF_COMPILED);
578
579 if (lambdaForm.forceInline) {
580 // Force inlining of this invoker method.
581 annotations.add(FORCEINLINE);
582 } else {
583 annotations.add(DONTINLINE);
584 }
585 mb.accept(RuntimeVisibleAnnotationsAttribute.of(annotations));
586
587 classData(lambdaForm); // keep LambdaForm instance & its compiled form lifetime tightly coupled.
588
589 mb.withCode(new Consumer<CodeBuilder>() {
590 @Override
591 public void accept(CodeBuilder cob) {
592 if (lambdaForm.customized != null) {
593 // Since LambdaForm is customized for a particular MethodHandle, it's safe to substitute
594 // receiver MethodHandle (at slot #0) with an embedded constant and use it instead.
595 // It enables more efficient code generation in some situations, since embedded constants
596 // are compile-time constants for JIT compiler.
597 cob.getstatic(classDesc, classData(lambdaForm.customized), CD_MethodHandle)
598 .checkcast(CD_MethodHandle);
599 assert(checkActualReceiver(cob)); // expects MethodHandle on top of the stack
600 cob.astore(0);
601 }
602
603 // iterate over the form's names, generating bytecode instructions for each
604 // start iterating at the first name following the arguments
605 Name onStack = null;
606 for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) {
607 Name name = lambdaForm.names[i];
608
609 emitStoreResult(cob, onStack);
610 onStack = name; // unless otherwise modified below
611 MethodHandleImpl.Intrinsic intr = name.function.intrinsicName();
612 switch (intr) {
613 case SELECT_ALTERNATIVE:
614 assert lambdaForm.isSelectAlternative(i);
615 if (PROFILE_GWT) {
616 assert(name.arguments[0] instanceof Name n &&
617 n.refersTo(MethodHandleImpl.class, "profileBoolean"));
618 mb.with(RuntimeVisibleAnnotationsAttribute.of(List.of(INJECTEDPROFILE)));
619 }
620 onStack = emitSelectAlternative(cob, name, lambdaForm.names[i+1]);
621 i++; // skip MH.invokeBasic of the selectAlternative result
622 continue;
623 case GUARD_WITH_CATCH:
624 assert lambdaForm.isGuardWithCatch(i);
625 onStack = emitGuardWithCatch(cob, i);
626 i += 2; // jump to the end of GWC idiom
627 continue;
628 case TRY_FINALLY:
629 assert lambdaForm.isTryFinally(i);
630 onStack = emitTryFinally(cob, i);
631 i += 2; // jump to the end of the TF idiom
632 continue;
633 case TABLE_SWITCH:
634 assert lambdaForm.isTableSwitch(i);
635 int numCases = (Integer) name.function.intrinsicData();
636 onStack = emitTableSwitch(cob, i, numCases);
637 i += 2; // jump to the end of the TS idiom
638 continue;
639 case LOOP:
640 assert lambdaForm.isLoop(i);
641 onStack = emitLoop(cob, i);
642 i += 2; // jump to the end of the LOOP idiom
643 continue;
644 case ARRAY_LOAD:
645 emitArrayLoad(cob, name);
646 continue;
647 case ARRAY_STORE:
648 emitArrayStore(cob, name);
649 continue;
650 case ARRAY_LENGTH:
651 emitArrayLength(cob, name);
652 continue;
653 case IDENTITY:
654 assert(name.arguments.length == 1);
655 emitPushArguments(cob, name, 0);
656 continue;
657 case ZERO:
658 assert(name.arguments.length == 0);
659 cob.loadConstant((ConstantDesc)name.type.basicTypeWrapper().zero());
660 continue;
661 case NONE:
662 // no intrinsic associated
663 break;
664 default:
665 throw newInternalError("Unknown intrinsic: "+intr);
666 }
667
668 MemberName member = name.function.member();
669 if (isStaticallyInvocable(member)) {
670 emitStaticInvoke(cob, member, name);
671 } else {
672 emitInvoke(cob, name);
673 }
674 }
675
676 // return statement
677 emitReturn(cob, onStack);
678 }
679 });
680 }
681 });
682 }
683
684 /**
685 * The BytecodeGenerationException.
686 */
687 @SuppressWarnings("serial")
688 static final class BytecodeGenerationException extends RuntimeException {
689 BytecodeGenerationException(Exception cause) {
690 super(cause);
691 }
692 }
693
694 void emitArrayLoad(CodeBuilder cob, Name name) {
695 Class<?> elementType = name.function.methodType().parameterType(0).getComponentType();
696 assert elementType != null;
697 emitPushArguments(cob, name, 0);
698 if (elementType.isPrimitive()) {
699 cob.arrayLoad(TypeKind.from(elementType));
700 } else {
701 cob.aaload();
702 }
703 }
704
705 void emitArrayStore(CodeBuilder cob, Name name) {
706 Class<?> elementType = name.function.methodType().parameterType(0).getComponentType();
707 assert elementType != null;
708 emitPushArguments(cob, name, 0);
709 if (elementType.isPrimitive()) {
710 cob.arrayStore(TypeKind.from(elementType));
711 } else {
712 cob.aastore();
713 }
714 }
715
716 void emitArrayLength(CodeBuilder cob, Name name) {
717 assert name.function.methodType().parameterType(0).isArray();
718 emitPushArguments(cob, name, 0);
719 cob.arraylength();
720 }
721
722 /**
723 * Emit an invoke for the given name.
724 */
725 void emitInvoke(CodeBuilder cob, Name name) {
726 assert(!name.isLinkerMethodInvoke()); // should use the static path for these
727 if (true) {
728 // push receiver
729 MethodHandle target = name.function.resolvedHandle();
730 assert(target != null) : name.exprString();
731 cob.getstatic(classDesc, classData(target), CD_MethodHandle);
732 emitReferenceCast(cob, MethodHandle.class, target);
733 } else {
734 // load receiver
735 cob.aload(0);
736 emitReferenceCast(cob, MethodHandle.class, null);
737 cob.getfield(CD_MethodHandle, "form", CD_LambdaForm)
738 .getfield(CD_LambdaForm, "names", CD_LambdaForm_Name);
739 // TODO more to come
740 }
741
742 // push arguments
743 emitPushArguments(cob, name, 0);
744
745 // invocation
746 MethodType type = name.function.methodType();
747 cob.invokevirtual(CD_MethodHandle, "invokeBasic", methodDesc(type.basicType()));
748 }
749
750 private static final Class<?>[] STATICALLY_INVOCABLE_PACKAGES = {
751 // Sample classes from each package we are willing to bind to statically:
752 java.lang.Object.class,
753 java.util.Arrays.class,
754 jdk.internal.misc.Unsafe.class
755 //MethodHandle.class already covered
756 };
757
758 static boolean isStaticallyInvocable(NamedFunction ... functions) {
759 for (NamedFunction nf : functions) {
760 if (!isStaticallyInvocable(nf.member())) {
761 return false;
762 }
763 }
764 return true;
765 }
766
767 static boolean isStaticallyInvocable(Name name) {
768 return isStaticallyInvocable(name.function.member());
769 }
770
771 static boolean isStaticallyInvocable(MemberName member) {
772 if (member == null) return false;
773 if (member.isConstructor()) return false;
774 Class<?> cls = member.getDeclaringClass();
775 // Fast-path non-private members declared by MethodHandles, which is a common
776 // case
777 if (MethodHandle.class.isAssignableFrom(cls) && !member.isPrivate()) {
778 assert(isStaticallyInvocableType(member.getMethodOrFieldType()));
779 return true;
780 }
781 if (cls.isArray() || cls.isPrimitive())
782 return false; // FIXME
783 if (cls.isAnonymousClass() || cls.isLocalClass())
784 return false; // inner class of some sort
785 if (cls.getClassLoader() != MethodHandle.class.getClassLoader())
786 return false; // not on BCP
787 if (cls.isHidden())
788 return false;
789 if (!isStaticallyInvocableType(member.getMethodOrFieldType()))
790 return false;
791 if (!member.isPrivate() && VerifyAccess.isSamePackage(MethodHandle.class, cls))
792 return true; // in java.lang.invoke package
793 if (member.isPublic() && isStaticallyNameable(cls))
794 return true;
795 return false;
796 }
797
798 private static boolean isStaticallyInvocableType(MethodType mtype) {
799 if (!isStaticallyNameable(mtype.returnType()))
800 return false;
801 for (Class<?> ptype : mtype.ptypes())
802 if (!isStaticallyNameable(ptype))
803 return false;
804 return true;
805 }
806
807 static boolean isStaticallyNameable(Class<?> cls) {
808 if (cls == Object.class)
809 return true;
810 if (MethodHandle.class.isAssignableFrom(cls)) {
811 assert(!cls.isHidden());
812 return true;
813 }
814 while (cls.isArray())
815 cls = cls.getComponentType();
816 if (cls.isPrimitive())
817 return true; // int[].class, for example
818 if (cls.isHidden())
819 return false;
820 // could use VerifyAccess.isClassAccessible but the following is a safe approximation
821 if (cls.getClassLoader() != Object.class.getClassLoader())
822 return false;
823 if (VerifyAccess.isSamePackage(MethodHandle.class, cls))
824 return true;
825 if (!Modifier.isPublic(cls.getModifiers()))
826 return false;
827 for (Class<?> pkgcls : STATICALLY_INVOCABLE_PACKAGES) {
828 if (VerifyAccess.isSamePackage(pkgcls, cls))
829 return true;
830 }
831 return false;
832 }
833
834 void emitStaticInvoke(CodeBuilder cob, Name name) {
835 emitStaticInvoke(cob, name.function.member(), name);
836 }
837
838 /**
839 * Emit an invoke for the given name, using the MemberName directly.
840 */
841 void emitStaticInvoke(CodeBuilder cob, MemberName member, Name name) {
842 assert(member.equals(name.function.member()));
843 Class<?> defc = member.getDeclaringClass();
844 ClassDesc cdesc = classDesc(defc);
845 String mname = member.getName();
846 byte refKind = member.getReferenceKind();
847 if (refKind == REF_invokeSpecial) {
848 // in order to pass the verifier, we need to convert this to invokevirtual in all cases
849 assert(member.canBeStaticallyBound()) : member;
850 refKind = REF_invokeVirtual;
851 }
852
853 assert(!(member.getDeclaringClass().isInterface() && refKind == REF_invokeVirtual));
854
855 // push arguments
856 emitPushArguments(cob, name, 0);
857
858 // invocation
859 if (member.isMethod()) {
860 var methodTypeDesc = methodDesc(member.getMethodType());
861 cob.invoke(refKindOpcode(refKind), cdesc, mname, methodTypeDesc,
862 member.getDeclaringClass().isInterface());
863 } else {
864 var fieldTypeDesc = classDesc(member.getFieldType());
865 cob.fieldAccess(refKindOpcode(refKind), cdesc, mname, fieldTypeDesc);
866 }
867 // Issue a type assertion for the result, so we can avoid casts later.
868 if (name.type == L_TYPE) {
869 Class<?> rtype = member.getInvocationType().returnType();
870 assert(!rtype.isPrimitive());
871 if (rtype != Object.class && !rtype.isInterface()) {
872 assertStaticType(rtype, name);
873 }
874 }
875 }
876
877 Opcode refKindOpcode(byte refKind) {
878 switch (refKind) {
879 case REF_invokeVirtual: return Opcode.INVOKEVIRTUAL;
880 case REF_invokeStatic: return Opcode.INVOKESTATIC;
881 case REF_invokeSpecial: return Opcode.INVOKESPECIAL;
882 case REF_invokeInterface: return Opcode.INVOKEINTERFACE;
883 case REF_getField: return Opcode.GETFIELD;
884 case REF_putField: return Opcode.PUTFIELD;
885 case REF_getStatic: return Opcode.GETSTATIC;
886 case REF_putStatic: return Opcode.PUTSTATIC;
887 }
888 throw new InternalError("refKind="+refKind);
889 }
890
891 /**
892 * Emit bytecode for the selectAlternative idiom.
893 *
894 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithTest):
895 * <blockquote><pre>{@code
896 * Lambda(a0:L,a1:I)=>{
897 * t2:I=foo.test(a1:I);
898 * t3:L=MethodHandleImpl.selectAlternative(t2:I,(MethodHandle(int)int),(MethodHandle(int)int));
899 * t4:I=MethodHandle.invokeBasic(t3:L,a1:I);t4:I}
900 * }</pre></blockquote>
901 */
902 private Name emitSelectAlternative(CodeBuilder cob, Name selectAlternativeName, Name invokeBasicName) {
903 assert isStaticallyInvocable(invokeBasicName);
904
905 Name receiver = (Name) invokeBasicName.arguments[0];
906
907 Label L_fallback = cob.newLabel();
908 Label L_done = cob.newLabel();
909
910 // load test result
911 emitPushArgument(cob, selectAlternativeName, 0);
912
913 // if_icmpne L_fallback
914 cob.ifeq(L_fallback);
915
916 // invoke selectAlternativeName.arguments[1]
917 Class<?>[] preForkClasses = localClasses.clone();
918 emitPushArgument(cob, selectAlternativeName, 1); // get 2nd argument of selectAlternative
919 emitStoreInsn(cob, TypeKind.ReferenceType, receiver.index()); // store the MH in the receiver slot
920 emitStaticInvoke(cob, invokeBasicName);
921
922 // goto L_done
923 cob.goto_w(L_done);
924
925 // L_fallback:
926 cob.labelBinding(L_fallback);
927
928 // invoke selectAlternativeName.arguments[2]
929 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
930 emitPushArgument(cob, selectAlternativeName, 2); // get 3rd argument of selectAlternative
931 emitStoreInsn(cob, TypeKind.ReferenceType, receiver.index()); // store the MH in the receiver slot
932 emitStaticInvoke(cob, invokeBasicName);
933
934 // L_done:
935 cob.labelBinding(L_done);
936 // for now do not bother to merge typestate; just reset to the dominator state
937 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
938
939 return invokeBasicName; // return what's on stack
940 }
941
942 /**
943 * Emit bytecode for the guardWithCatch idiom.
944 *
945 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithCatch):
946 * <blockquote><pre>{@code
947 * guardWithCatch=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{
948 * t8:L=MethodHandle.invokeBasic(a4:L,a6:L,a7:L);
949 * t9:L=MethodHandleImpl.guardWithCatch(a1:L,a2:L,a3:L,t8:L);
950 * t10:I=MethodHandle.invokeBasic(a5:L,t9:L);t10:I}
951 * }</pre></blockquote>
952 *
953 * It is compiled into bytecode equivalent of the following code:
954 * <blockquote><pre>{@code
955 * try {
956 * return a1.invokeBasic(a6, a7);
957 * } catch (Throwable e) {
958 * if (!a2.isInstance(e)) throw e;
959 * return a3.invokeBasic(ex, a6, a7);
960 * }}</pre></blockquote>
961 */
962 private Name emitGuardWithCatch(CodeBuilder cob, int pos) {
963 Name args = lambdaForm.names[pos];
964 Name invoker = lambdaForm.names[pos+1];
965 Name result = lambdaForm.names[pos+2];
966
967 Label L_startBlock = cob.newLabel();
968 Label L_endBlock = cob.newLabel();
969 Label L_handler = cob.newLabel();
970 Label L_done = cob.newLabel();
971
972 Class<?> returnType = result.function.resolvedHandle().type().returnType();
973 MethodType type = args.function.resolvedHandle().type()
974 .dropParameterTypes(0,1)
975 .changeReturnType(returnType);
976
977 cob.exceptionCatch(L_startBlock, L_endBlock, L_handler, CD_Throwable);
978
979 // Normal case
980 cob.labelBinding(L_startBlock);
981 // load target
982 emitPushArgument(cob, invoker, 0);
983 emitPushArguments(cob, args, 1); // skip 1st argument: method handle
984 cob.invokevirtual(CD_MethodHandle, "invokeBasic", methodDesc(type.basicType()));
985 cob.labelBinding(L_endBlock);
986 cob.goto_w(L_done);
987
988 // Exceptional case
989 cob.labelBinding(L_handler);
990
991 // Check exception's type
992 cob.dup();
993 // load exception class
994 emitPushArgument(cob, invoker, 1);
995 cob.swap();
996 cob.invokevirtual(CD_Class, "isInstance", MTD_boolean_Object);
997 Label L_rethrow = cob.newLabel();
998 cob.ifeq(L_rethrow);
999
1000 // Invoke catcher
1001 // load catcher
1002 emitPushArgument(cob, invoker, 2);
1003 cob.swap();
1004 emitPushArguments(cob, args, 1); // skip 1st argument: method handle
1005 MethodType catcherType = type.insertParameterTypes(0, Throwable.class);
1006 cob.invokevirtual(CD_MethodHandle, "invokeBasic", methodDesc(catcherType.basicType()));
1007 cob.goto_w(L_done);
1008
1009 cob.labelBinding(L_rethrow);
1010 cob.athrow();
1011
1012 cob.labelBinding(L_done);
1013
1014 return result;
1015 }
1016
1017 /**
1018 * Emit bytecode for the tryFinally idiom.
1019 * <p>
1020 * The pattern looks like (Cf. MethodHandleImpl.makeTryFinally):
1021 * <blockquote><pre>{@code
1022 * // a0: BMH
1023 * // a1: target, a2: cleanup
1024 * // a3: box, a4: unbox
1025 * // a5 (and following): arguments
1026 * tryFinally=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L)=>{
1027 * t6:L=MethodHandle.invokeBasic(a3:L,a5:L); // box the arguments into an Object[]
1028 * t7:L=MethodHandleImpl.tryFinally(a1:L,a2:L,t6:L); // call the tryFinally executor
1029 * t8:L=MethodHandle.invokeBasic(a4:L,t7:L);t8:L} // unbox the result; return the result
1030 * }</pre></blockquote>
1031 * <p>
1032 * It is compiled into bytecode equivalent to the following code:
1033 * <blockquote><pre>{@code
1034 * Throwable t;
1035 * Object r;
1036 * try {
1037 * r = a1.invokeBasic(a5);
1038 * } catch (Throwable thrown) {
1039 * t = thrown;
1040 * throw t;
1041 * } finally {
1042 * r = a2.invokeBasic(t, r, a5);
1043 * }
1044 * return r;
1045 * }</pre></blockquote>
1046 * <p>
1047 * Specifically, the bytecode will have the following form (the stack effects are given for the beginnings of
1048 * blocks, and for the situations after executing the given instruction - the code will have a slightly different
1049 * shape if the return type is {@code void}):
1050 * <blockquote><pre>{@code
1051 * TRY: (--)
1052 * load target (-- target)
1053 * load args (-- args... target)
1054 * INVOKEVIRTUAL MethodHandle.invokeBasic (depends)
1055 * FINALLY_NORMAL: (-- r_2nd* r)
1056 * store returned value (--)
1057 * load cleanup (-- cleanup)
1058 * ACONST_NULL (-- t cleanup)
1059 * load returned value (-- r_2nd* r t cleanup)
1060 * load args (-- args... r_2nd* r t cleanup)
1061 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r_2nd* r)
1062 * GOTO DONE
1063 * CATCH: (-- t)
1064 * DUP (-- t t)
1065 * FINALLY_EXCEPTIONAL: (-- t t)
1066 * load cleanup (-- cleanup t t)
1067 * SWAP (-- t cleanup t)
1068 * load default for r (-- r_2nd* r t cleanup t)
1069 * load args (-- args... r_2nd* r t cleanup t)
1070 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r_2nd* r t)
1071 * POP/POP2* (-- t)
1072 * ATHROW
1073 * DONE: (-- r)
1074 * }</pre></blockquote>
1075 * * = depends on whether the return type takes up 2 stack slots.
1076 */
1077 private Name emitTryFinally(CodeBuilder cob, int pos) {
1078 Name args = lambdaForm.names[pos];
1079 Name invoker = lambdaForm.names[pos+1];
1080 Name result = lambdaForm.names[pos+2];
1081
1082 Label lFrom = cob.newLabel();
1083 Label lTo = cob.newLabel();
1084 Label lCatch = cob.newLabel();
1085 Label lDone = cob.newLabel();
1086
1087 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1088 BasicType basicReturnType = BasicType.basicType(returnType);
1089 boolean isNonVoid = returnType != void.class;
1090
1091 MethodType type = args.function.resolvedHandle().type()
1092 .dropParameterTypes(0,1)
1093 .changeReturnType(returnType);
1094 MethodType cleanupType = type.insertParameterTypes(0, Throwable.class);
1095 if (isNonVoid) {
1096 cleanupType = cleanupType.insertParameterTypes(1, returnType);
1097 }
1098 MethodTypeDesc cleanupDesc = methodDesc(cleanupType.basicType());
1099
1100 // exception handler table
1101 cob.exceptionCatch(lFrom, lTo, lCatch, CD_Throwable);
1102
1103 // TRY:
1104 cob.labelBinding(lFrom);
1105 emitPushArgument(cob, invoker, 0); // load target
1106 emitPushArguments(cob, args, 1); // load args (skip 0: method handle)
1107 cob.invokevirtual(CD_MethodHandle, "invokeBasic", methodDesc(type.basicType()));
1108 cob.labelBinding(lTo);
1109
1110 // FINALLY_NORMAL:
1111 int index = extendLocalsMap(new Class<?>[]{ returnType });
1112 if (isNonVoid) {
1113 emitStoreInsn(cob, basicReturnType.basicTypeKind(), index);
1114 }
1115 emitPushArgument(cob, invoker, 1); // load cleanup
1116 cob.loadConstant(null);
1117 if (isNonVoid) {
1118 emitLoadInsn(cob, basicReturnType.basicTypeKind(), index);
1119 }
1120 emitPushArguments(cob, args, 1); // load args (skip 0: method handle)
1121 cob.invokevirtual(CD_MethodHandle, "invokeBasic", cleanupDesc);
1122 cob.goto_w(lDone);
1123
1124 // CATCH:
1125 cob.labelBinding(lCatch);
1126 cob.dup();
1127
1128 // FINALLY_EXCEPTIONAL:
1129 emitPushArgument(cob, invoker, 1); // load cleanup
1130 cob.swap();
1131 if (isNonVoid) {
1132 emitZero(cob, BasicType.basicType(returnType)); // load default for result
1133 }
1134 emitPushArguments(cob, args, 1); // load args (skip 0: method handle)
1135 cob.invokevirtual(CD_MethodHandle, "invokeBasic", cleanupDesc);
1136 if (isNonVoid) {
1137 emitPopInsn(cob, basicReturnType);
1138 }
1139 cob.athrow();
1140
1141 // DONE:
1142 cob.labelBinding(lDone);
1143
1144 return result;
1145 }
1146
1147 private void emitPopInsn(CodeBuilder cob, BasicType type) {
1148 switch (type) {
1149 case I_TYPE, F_TYPE, L_TYPE -> cob.pop();
1150 case J_TYPE, D_TYPE -> cob.pop2();
1151 default -> throw new InternalError("unknown type: " + type);
1152 }
1153 }
1154
1155 private Name emitTableSwitch(CodeBuilder cob, int pos, int numCases) {
1156 Name args = lambdaForm.names[pos];
1157 Name invoker = lambdaForm.names[pos + 1];
1158 Name result = lambdaForm.names[pos + 2];
1159
1160 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1161 MethodType caseType = args.function.resolvedHandle().type()
1162 .dropParameterTypes(0, 1) // drop collector
1163 .changeReturnType(returnType);
1164 MethodTypeDesc caseDescriptor = methodDesc(caseType.basicType());
1165
1166 emitPushArgument(cob, invoker, 2); // push cases
1167 cob.getfield(CD_CasesHolder, "cases", CD_MethodHandle_array);
1168 int casesLocal = extendLocalsMap(new Class<?>[] { MethodHandle[].class });
1169 emitStoreInsn(cob, TypeKind.ReferenceType, casesLocal);
1170
1171 Label endLabel = cob.newLabel();
1172 Label defaultLabel = cob.newLabel();
1173 List<SwitchCase> cases = new ArrayList<>(numCases);
1174 for (int i = 0; i < numCases; i++) {
1175 cases.add(SwitchCase.of(i, cob.newLabel()));
1176 }
1177
1178 emitPushArgument(cob, invoker, 0); // push switch input
1179 cob.tableswitch(0, numCases - 1, defaultLabel, cases);
1180
1181 cob.labelBinding(defaultLabel);
1182 emitPushArgument(cob, invoker, 1); // push default handle
1183 emitPushArguments(cob, args, 1); // again, skip collector
1184 cob.invokevirtual(CD_MethodHandle, "invokeBasic", caseDescriptor);
1185 cob.goto_(endLabel);
1186
1187 for (int i = 0; i < numCases; i++) {
1188 cob.labelBinding(cases.get(i).target());
1189 // Load the particular case:
1190 emitLoadInsn(cob, TypeKind.ReferenceType, casesLocal);
1191 cob.loadConstant(i);
1192 cob.aaload();
1193
1194 // invoke it:
1195 emitPushArguments(cob, args, 1); // again, skip collector
1196 cob.invokevirtual(CD_MethodHandle, "invokeBasic", caseDescriptor);
1197
1198 cob.goto_(endLabel);
1199 }
1200
1201 cob.labelBinding(endLabel);
1202
1203 return result;
1204 }
1205
1206 /**
1207 * Emit bytecode for the loop idiom.
1208 * <p>
1209 * The pattern looks like (Cf. MethodHandleImpl.loop):
1210 * <blockquote><pre>{@code
1211 * // a0: BMH
1212 * // a1: LoopClauses (containing an array of arrays: inits, steps, preds, finis)
1213 * // a2: box, a3: unbox
1214 * // a4 (and following): arguments
1215 * loop=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L)=>{
1216 * t5:L=MethodHandle.invokeBasic(a2:L,a4:L); // box the arguments into an Object[]
1217 * t6:L=MethodHandleImpl.loop(bt:L,a1:L,t5:L); // call the loop executor (with supplied types in bt)
1218 * t7:L=MethodHandle.invokeBasic(a3:L,t6:L);t7:L} // unbox the result; return the result
1219 * }</pre></blockquote>
1220 * <p>
1221 * It is compiled into bytecode equivalent to the code seen in {@link MethodHandleImpl#loop(BasicType[],
1222 * MethodHandleImpl.LoopClauses, Object...)}, with the difference that no arrays
1223 * will be used for local state storage. Instead, the local state will be mapped to actual stack slots.
1224 * <p>
1225 * Bytecode generation applies an unrolling scheme to enable better bytecode generation regarding local state type
1226 * handling. The generated bytecode will have the following form ({@code void} types are ignored for convenience).
1227 * Assume there are {@code C} clauses in the loop.
1228 * <blockquote><pre>{@code
1229 * PREINIT: ALOAD_1
1230 * CHECKCAST LoopClauses
1231 * GETFIELD LoopClauses.clauses
1232 * ASTORE clauseDataIndex // place the clauses 2-dimensional array on the stack
1233 * INIT: (INIT_SEQ for clause 1)
1234 * ...
1235 * (INIT_SEQ for clause C)
1236 * LOOP: (LOOP_SEQ for clause 1)
1237 * ...
1238 * (LOOP_SEQ for clause C)
1239 * GOTO LOOP
1240 * DONE: ...
1241 * }</pre></blockquote>
1242 * <p>
1243 * The {@code INIT_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has
1244 * the following shape. Assume slot {@code vx} is used to hold the state for clause {@code x}.
1245 * <blockquote><pre>{@code
1246 * INIT_SEQ_x: ALOAD clauseDataIndex
1247 * ICONST_0
1248 * AALOAD // load the inits array
1249 * ICONST x
1250 * AALOAD // load the init handle for clause x
1251 * load args
1252 * INVOKEVIRTUAL MethodHandle.invokeBasic
1253 * store vx
1254 * }</pre></blockquote>
1255 * <p>
1256 * The {@code LOOP_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has
1257 * the following shape. Again, assume slot {@code vx} is used to hold the state for clause {@code x}.
1258 * <blockquote><pre>{@code
1259 * LOOP_SEQ_x: ALOAD clauseDataIndex
1260 * ICONST_1
1261 * AALOAD // load the steps array
1262 * ICONST x
1263 * AALOAD // load the step handle for clause x
1264 * load locals
1265 * load args
1266 * INVOKEVIRTUAL MethodHandle.invokeBasic
1267 * store vx
1268 * ALOAD clauseDataIndex
1269 * ICONST_2
1270 * AALOAD // load the preds array
1271 * ICONST x
1272 * AALOAD // load the pred handle for clause x
1273 * load locals
1274 * load args
1275 * INVOKEVIRTUAL MethodHandle.invokeBasic
1276 * IFNE LOOP_SEQ_x+1 // predicate returned false -> jump to next clause
1277 * ALOAD clauseDataIndex
1278 * ICONST_3
1279 * AALOAD // load the finis array
1280 * ICONST x
1281 * AALOAD // load the fini handle for clause x
1282 * load locals
1283 * load args
1284 * INVOKEVIRTUAL MethodHandle.invokeBasic
1285 * GOTO DONE // jump beyond end of clauses to return from loop
1286 * }</pre></blockquote>
1287 */
1288 private Name emitLoop(CodeBuilder cob, int pos) {
1289 Name args = lambdaForm.names[pos];
1290 Name invoker = lambdaForm.names[pos+1];
1291 Name result = lambdaForm.names[pos+2];
1292
1293 // extract clause and loop-local state types
1294 // find the type info in the loop invocation
1295 BasicType[] loopClauseTypes = (BasicType[]) invoker.arguments[0];
1296 Class<?>[] loopLocalStateTypes = Stream.of(loopClauseTypes)
1297 .filter(bt -> bt != BasicType.V_TYPE)
1298 .map(BasicType::basicTypeClass).toArray(Class<?>[]::new);
1299 Class<?>[] localTypes = new Class<?>[loopLocalStateTypes.length + 1];
1300 localTypes[0] = MethodHandleImpl.LoopClauses.class;
1301 System.arraycopy(loopLocalStateTypes, 0, localTypes, 1, loopLocalStateTypes.length);
1302
1303 final int clauseDataIndex = extendLocalsMap(localTypes);
1304 final int firstLoopStateIndex = clauseDataIndex + 1;
1305
1306 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1307 MethodType loopType = args.function.resolvedHandle().type()
1308 .dropParameterTypes(0,1)
1309 .changeReturnType(returnType);
1310 MethodType loopHandleType = loopType.insertParameterTypes(0, loopLocalStateTypes);
1311 MethodType predType = loopHandleType.changeReturnType(boolean.class);
1312 MethodType finiType = loopHandleType;
1313
1314 final int nClauses = loopClauseTypes.length;
1315
1316 // indices to invoker arguments to load method handle arrays
1317 final int inits = 1;
1318 final int steps = 2;
1319 final int preds = 3;
1320 final int finis = 4;
1321
1322 Label lLoop = cob.newLabel();
1323 Label lDone = cob.newLabel();
1324 Label lNext;
1325
1326 // PREINIT:
1327 emitPushArgument(cob, MethodHandleImpl.LoopClauses.class, invoker.arguments[1]);
1328 cob.getfield(CD_LoopClauses, "clauses", CD_MethodHandle_array2);
1329 emitStoreInsn(cob, TypeKind.ReferenceType, clauseDataIndex);
1330
1331 // INIT:
1332 for (int c = 0, state = 0; c < nClauses; ++c) {
1333 MethodType cInitType = loopType.changeReturnType(loopClauseTypes[c].basicTypeClass());
1334 emitLoopHandleInvoke(cob, invoker, inits, c, args, false, cInitType, loopLocalStateTypes, clauseDataIndex,
1335 firstLoopStateIndex);
1336 if (cInitType.returnType() != void.class) {
1337 emitStoreInsn(cob, BasicType.basicType(cInitType.returnType()).basicTypeKind(), firstLoopStateIndex + state);
1338 ++state;
1339 }
1340 }
1341
1342 // LOOP:
1343 cob.labelBinding(lLoop);
1344
1345 for (int c = 0, state = 0; c < nClauses; ++c) {
1346 lNext = cob.newLabel();
1347
1348 MethodType stepType = loopHandleType.changeReturnType(loopClauseTypes[c].basicTypeClass());
1349 boolean isVoid = stepType.returnType() == void.class;
1350
1351 // invoke loop step
1352 emitLoopHandleInvoke(cob, invoker, steps, c, args, true, stepType, loopLocalStateTypes, clauseDataIndex,
1353 firstLoopStateIndex);
1354 if (!isVoid) {
1355 emitStoreInsn(cob, BasicType.basicType(stepType.returnType()).basicTypeKind(), firstLoopStateIndex + state);
1356 ++state;
1357 }
1358
1359 // invoke loop predicate
1360 emitLoopHandleInvoke(cob, invoker, preds, c, args, true, predType, loopLocalStateTypes, clauseDataIndex,
1361 firstLoopStateIndex);
1362 cob.ifne(lNext);
1363
1364 // invoke fini
1365 emitLoopHandleInvoke(cob, invoker, finis, c, args, true, finiType, loopLocalStateTypes, clauseDataIndex,
1366 firstLoopStateIndex);
1367 cob.goto_w(lDone);
1368
1369 // this is the beginning of the next loop clause
1370 cob.labelBinding(lNext);
1371 }
1372
1373 cob.goto_w(lLoop);
1374
1375 // DONE:
1376 cob.labelBinding(lDone);
1377
1378 return result;
1379 }
1380
1381 private int extendLocalsMap(Class<?>[] types) {
1382 int firstSlot = localsMap.length - 1;
1383 localsMap = Arrays.copyOf(localsMap, localsMap.length + types.length);
1384 localClasses = Arrays.copyOf(localClasses, localClasses.length + types.length);
1385 System.arraycopy(types, 0, localClasses, firstSlot, types.length);
1386 int index = localsMap[firstSlot - 1] + 1;
1387 int lastSlots = 0;
1388 for (int i = 0; i < types.length; ++i) {
1389 localsMap[firstSlot + i] = index;
1390 lastSlots = BasicType.basicType(localClasses[firstSlot + i]).basicTypeSlots();
1391 index += lastSlots;
1392 }
1393 localsMap[localsMap.length - 1] = index - lastSlots;
1394 return firstSlot;
1395 }
1396
1397 private void emitLoopHandleInvoke(CodeBuilder cob, Name holder, int handles, int clause, Name args, boolean pushLocalState,
1398 MethodType type, Class<?>[] loopLocalStateTypes, int clauseDataSlot,
1399 int firstLoopStateSlot) {
1400 // load handle for clause
1401 emitPushClauseArray(cob, clauseDataSlot, handles);
1402 cob.loadConstant(clause);
1403 cob.aaload();
1404 // load loop state (preceding the other arguments)
1405 if (pushLocalState) {
1406 for (int s = 0; s < loopLocalStateTypes.length; ++s) {
1407 emitLoadInsn(cob, BasicType.basicType(loopLocalStateTypes[s]).basicTypeKind(), firstLoopStateSlot + s);
1408 }
1409 }
1410 // load loop args (skip 0: method handle)
1411 emitPushArguments(cob, args, 1);
1412 cob.invokevirtual(CD_MethodHandle, "invokeBasic", methodDesc(type));
1413 }
1414
1415 private void emitPushClauseArray(CodeBuilder cob, int clauseDataSlot, int which) {
1416 emitLoadInsn(cob, TypeKind.ReferenceType, clauseDataSlot);
1417 cob.loadConstant(which - 1);
1418 cob.aaload();
1419 }
1420
1421 private void emitZero(CodeBuilder cob, BasicType type) {
1422 switch (type) {
1423 case I_TYPE -> cob.iconst_0();
1424 case J_TYPE -> cob.lconst_0();
1425 case F_TYPE -> cob.fconst_0();
1426 case D_TYPE -> cob.dconst_0();
1427 case L_TYPE -> cob.aconst_null();
1428 default -> throw new InternalError("unknown type: " + type);
1429 };
1430 }
1431
1432 private void emitPushArguments(CodeBuilder cob, Name args, int start) {
1433 MethodType type = args.function.methodType();
1434 for (int i = start; i < args.arguments.length; i++) {
1435 emitPushArgument(cob, type.parameterType(i), args.arguments[i]);
1436 }
1437 }
1438
1439 private void emitPushArgument(CodeBuilder cob, Name name, int paramIndex) {
1440 Object arg = name.arguments[paramIndex];
1441 Class<?> ptype = name.function.methodType().parameterType(paramIndex);
1442 emitPushArgument(cob, ptype, arg);
1443 }
1444
1445 private void emitPushArgument(CodeBuilder cob, Class<?> ptype, Object arg) {
1446 BasicType bptype = basicType(ptype);
1447 if (arg instanceof Name n) {
1448 emitLoadInsn(cob, n.type.basicTypeKind(), n.index());
1449 emitImplicitConversion(cob, n.type, ptype, n);
1450 } else if ((arg == null || arg instanceof String) && bptype == L_TYPE) {
1451 cob.loadConstant((ConstantDesc)arg);
1452 } else {
1453 if (Wrapper.isWrapperType(arg.getClass()) && bptype != L_TYPE) {
1454 cob.loadConstant((ConstantDesc)arg);
1455 } else {
1456 cob.getstatic(classDesc, classData(arg), CD_Object);
1457 emitImplicitConversion(cob, L_TYPE, ptype, arg);
1458 }
1459 }
1460 }
1461
1462 /**
1463 * Store the name to its local, if necessary.
1464 */
1465 private void emitStoreResult(CodeBuilder cob, Name name) {
1466 if (name != null && name.type != V_TYPE) {
1467 // non-void: actually assign
1468 emitStoreInsn(cob, name.type.basicTypeKind(), name.index());
1469 }
1470 }
1471
1472 /**
1473 * Emits a return statement from a LF invoker. If required, the result type is cast to the correct return type.
1474 */
1475 private void emitReturn(CodeBuilder cob, Name onStack) {
1476 // return statement
1477 Class<?> rclass = invokerType.returnType();
1478 BasicType rtype = lambdaForm.returnType();
1479 assert(rtype == basicType(rclass)); // must agree
1480 if (rtype == V_TYPE) {
1481 // void
1482 cob.return_();
1483 // it doesn't matter what rclass is; the JVM will discard any value
1484 } else {
1485 LambdaForm.Name rn = lambdaForm.names[lambdaForm.result];
1486
1487 // put return value on the stack if it is not already there
1488 if (rn != onStack) {
1489 emitLoadInsn(cob, rtype.basicTypeKind(), lambdaForm.result);
1490 }
1491
1492 emitImplicitConversion(cob, rtype, rclass, rn);
1493
1494 // generate actual return statement
1495 cob.return_(rtype.basicTypeKind());
1496 }
1497 }
1498
1499 /**
1500 * Emit a type conversion bytecode casting from "from" to "to".
1501 */
1502 private void emitPrimCast(CodeBuilder cob, TypeKind from, TypeKind to) {
1503 // Here's how.
1504 // - indicates forbidden
1505 // <-> indicates implicit
1506 // to ----> boolean byte short char int long float double
1507 // from boolean <-> - - - - - - -
1508 // byte - <-> i2s i2c <-> i2l i2f i2d
1509 // short - i2b <-> i2c <-> i2l i2f i2d
1510 // char - i2b i2s <-> <-> i2l i2f i2d
1511 // int - i2b i2s i2c <-> i2l i2f i2d
1512 // long - l2i,i2b l2i,i2s l2i,i2c l2i <-> l2f l2d
1513 // float - f2i,i2b f2i,i2s f2i,i2c f2i f2l <-> f2d
1514 // double - d2i,i2b d2i,i2s d2i,i2c d2i d2l d2f <->
1515 if (from != to && from != TypeKind.BooleanType) try {
1516 cob.conversion(from, to);
1517 } catch (IllegalArgumentException e) {
1518 throw new IllegalStateException("unhandled prim cast: " + from + "2" + to);
1519 }
1520 }
1521
1522 /**
1523 * Generate bytecode for a LambdaForm.vmentry which calls interpretWithArguments.
1524 */
1525 static MemberName generateLambdaFormInterpreterEntryPoint(MethodType mt) {
1526 assert(isValidSignature(basicTypeSignature(mt)));
1527 String name = "interpret_"+basicTypeChar(mt.returnType());
1528 MethodType type = mt; // includes leading argument
1529 type = type.changeParameterType(0, MethodHandle.class);
1530 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("LFI", name, type);
1531 return g.loadMethod(g.generateLambdaFormInterpreterEntryPointBytes());
1532 }
1533
1534 private byte[] generateLambdaFormInterpreterEntryPointBytes() {
1535 final byte[] classFile = classFileSetup(new Consumer<ClassBuilder>() {
1536 @Override
1537 public void accept(ClassBuilder clb) {
1538 methodSetup(clb, new Consumer<MethodBuilder>() {
1539 @Override
1540 public void accept(MethodBuilder mb) {
1541
1542 mb.with(RuntimeVisibleAnnotationsAttribute.of(List.of(
1543 HIDDEN, // Suppress this method in backtraces displayed to the user.
1544 DONTINLINE // Don't inline the interpreter entry.
1545 )));
1546
1547 mb.withCode(new Consumer<CodeBuilder>() {
1548 @Override
1549 public void accept(CodeBuilder cob) {
1550 // create parameter array
1551 cob.loadConstant(invokerType.parameterCount());
1552 cob.anewarray(CD_Object);
1553
1554 // fill parameter array
1555 for (int i = 0; i < invokerType.parameterCount(); i++) {
1556 Class<?> ptype = invokerType.parameterType(i);
1557 cob.dup();
1558 cob.loadConstant(i);
1559 emitLoadInsn(cob, basicType(ptype).basicTypeKind(), i);
1560 // box if primitive type
1561 if (ptype.isPrimitive()) {
1562 emitBoxing(cob, TypeKind.from(ptype));
1563 }
1564 cob.aastore();
1565 }
1566 // invoke
1567 cob.aload(0);
1568 cob.getfield(CD_MethodHandle, "form", CD_LambdaForm);
1569 cob.swap(); // swap form and array; avoid local variable
1570 cob.invokevirtual(CD_LambdaForm, "interpretWithArguments", MethodTypeDescImpl.ofValidated(CD_Object, CD_Object_array));
1571
1572 // maybe unbox
1573 Class<?> rtype = invokerType.returnType();
1574 TypeKind rtypeK = TypeKind.from(rtype);
1575 if (rtype.isPrimitive() && rtype != void.class) {
1576 emitUnboxing(cob, rtypeK);
1577 }
1578
1579 // return statement
1580 cob.return_(rtypeK);
1581 }
1582 });
1583 }
1584 });
1585 clinit(clb, classDesc, classData);
1586 bogusMethod(clb, invokerType);
1587 }
1588 });
1589 return classFile;
1590 }
1591
1592 /**
1593 * Generate bytecode for a NamedFunction invoker.
1594 */
1595 static MemberName generateNamedFunctionInvoker(MethodTypeForm typeForm) {
1596 MethodType invokerType = NamedFunction.INVOKER_METHOD_TYPE;
1597 String invokerName = "invoke_" + shortenSignature(basicTypeSignature(typeForm.erasedType()));
1598 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("NFI", invokerName, invokerType);
1599 return g.loadMethod(g.generateNamedFunctionInvokerImpl(typeForm));
1600 }
1601
1602 private byte[] generateNamedFunctionInvokerImpl(MethodTypeForm typeForm) {
1603 MethodType dstType = typeForm.erasedType();
1604 final byte[] classFile = classFileSetup(new Consumer<ClassBuilder>() {
1605 @Override
1606 public void accept(ClassBuilder clb) {
1607 methodSetup(clb, new Consumer<MethodBuilder>() {
1608 @Override
1609 public void accept(MethodBuilder mb) {
1610
1611 mb.with(RuntimeVisibleAnnotationsAttribute.of(List.of(
1612 HIDDEN, // Suppress this method in backtraces displayed to the user.
1613 FORCEINLINE // Force inlining of this invoker method.
1614 )));
1615
1616 mb.withCode(new Consumer<CodeBuilder>() {
1617 @Override
1618 public void accept(CodeBuilder cob) {
1619 // Load receiver
1620 cob.aload(0);
1621
1622 // Load arguments from array
1623 for (int i = 0; i < dstType.parameterCount(); i++) {
1624 cob.aload(1);
1625 cob.loadConstant(i);
1626 cob.aaload();
1627
1628 // Maybe unbox
1629 Class<?> dptype = dstType.parameterType(i);
1630 if (dptype.isPrimitive()) {
1631 TypeKind dstTK = TypeKind.from(dptype);
1632 TypeKind srcTK = dstTK.asLoadable();
1633 emitUnboxing(cob, srcTK);
1634 emitPrimCast(cob, srcTK, dstTK);
1635 }
1636 }
1637
1638 // Invoke
1639 MethodTypeDesc targetDesc = methodDesc(dstType.basicType());
1640 cob.invokevirtual(CD_MethodHandle, "invokeBasic", targetDesc);
1641
1642 // Box primitive types
1643 Class<?> rtype = dstType.returnType();
1644 if (rtype != void.class && rtype.isPrimitive()) {
1645 TypeKind srcTK = TypeKind.from(rtype);
1646 TypeKind dstTK = srcTK.asLoadable();
1647 // boolean casts not allowed
1648 emitPrimCast(cob, srcTK, dstTK);
1649 emitBoxing(cob, dstTK);
1650 }
1651
1652 // If the return type is void we return a null reference.
1653 if (rtype == void.class) {
1654 cob.aconst_null();
1655 }
1656 cob.areturn(); // NOTE: NamedFunction invokers always return a reference value.
1657 }
1658 });
1659 }
1660 });
1661 clinit(clb, classDesc, classData);
1662 bogusMethod(clb, dstType);
1663 }
1664 });
1665 return classFile;
1666 }
1667
1668 /**
1669 * Emit a bogus method that just loads some string constants. This is to get the constants into the constant pool
1670 * for debugging purposes.
1671 */
1672 private void bogusMethod(ClassBuilder clb, Object os) {
1673 if (dumper().isEnabled()) {
1674 clb.withMethod("dummy", MTD_void, ACC_STATIC, new MethodBody(new Consumer<CodeBuilder>() {
1675 @Override
1676 public void accept(CodeBuilder cob) {
1677 cob.loadConstant(os.toString());
1678 cob.pop();
1679 cob.return_();
1680 }
1681 }));
1682 }
1683 }
1684
1685 static ClassDesc classDesc(Class<?> cls) {
1686 assert(VerifyAccess.ensureTypeVisible(cls, Object.class)) : cls.getName();
1687 return cls.isPrimitive() ? Wrapper.forPrimitiveType(cls).basicClassDescriptor()
1688 : cls == MethodHandle.class ? CD_MethodHandle
1689 : cls == DirectMethodHandle.class ? CD_DirectMethodHandle
1690 : cls == Object.class ? CD_Object
1691 : ReferenceClassDescImpl.ofValidated(cls.descriptorString());
1692 }
1693
1694 static MethodTypeDesc methodDesc(MethodType mt) {
1695 var params = new ClassDesc[mt.parameterCount()];
1696 for (int i = 0; i < params.length; i++) {
1697 params[i] = classDesc(mt.parameterType(i));
1698 }
1699 return MethodTypeDescImpl.ofValidated(classDesc(mt.returnType()), params);
1700 }
1701 }