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 jdk.internal.org.objectweb.asm.ClassWriter;
29 import jdk.internal.org.objectweb.asm.FieldVisitor;
30 import jdk.internal.org.objectweb.asm.Label;
31 import jdk.internal.org.objectweb.asm.MethodVisitor;
32 import jdk.internal.org.objectweb.asm.Opcodes;
33 import jdk.internal.org.objectweb.asm.Type;
34 import sun.invoke.util.VerifyAccess;
35 import sun.invoke.util.VerifyType;
36 import sun.invoke.util.Wrapper;
37
38 import java.lang.reflect.Modifier;
39 import java.util.ArrayList;
40 import java.util.Arrays;
41 import java.util.HashMap;
42 import java.util.List;
43 import java.util.Set;
44 import java.util.stream.Stream;
45
46 import static java.lang.invoke.LambdaForm.BasicType;
47 import static java.lang.invoke.LambdaForm.BasicType.*;
48 import static java.lang.invoke.LambdaForm.*;
49 import static java.lang.invoke.MethodHandleNatives.Constants.*;
50 import static java.lang.invoke.MethodHandleStatics.*;
51 import static java.lang.invoke.MethodHandles.Lookup.*;
52
53 /**
54 * Code generation backend for LambdaForm.
55 * <p>
56 * @author John Rose, JSR 292 EG
57 */
58 class InvokerBytecodeGenerator {
59 /** Define class names for convenience. */
60 private static final String MH = "java/lang/invoke/MethodHandle";
61 private static final String MHI = "java/lang/invoke/MethodHandleImpl";
62 private static final String LF = "java/lang/invoke/LambdaForm";
63 private static final String LFN = "java/lang/invoke/LambdaForm$Name";
64 private static final String CLS = "java/lang/Class";
65 private static final String OBJ = "java/lang/Object";
66 private static final String OBJARY = "[Ljava/lang/Object;";
67
68 private static final String LOOP_CLAUSES = MHI + "$LoopClauses";
69 private static final String MHARY2 = "[[L" + MH + ";";
70 private static final String MH_SIG = "L" + MH + ";";
71
72
73 private static final String LF_SIG = "L" + LF + ";";
74 private static final String LFN_SIG = "L" + LFN + ";";
75 private static final String LL_SIG = "(L" + OBJ + ";)L" + OBJ + ";";
76 private static final String LLV_SIG = "(L" + OBJ + ";L" + OBJ + ";)V";
77 private static final String CLASS_PREFIX = LF + "$";
78 private static final String SOURCE_PREFIX = "LambdaForm$";
79
80 /** Name of its super class*/
81 static final String INVOKER_SUPER_NAME = OBJ;
82
83 /** Name of new class */
84 private final String name;
85 private final String className;
86
87 private final LambdaForm lambdaForm;
88 private final String invokerName;
89 private final MethodType invokerType;
90
91 /** Info about local variables in compiled lambda form */
92 private int[] localsMap; // index
93 private Class<?>[] localClasses; // type
94
95 /** ASM bytecode generation. */
96 private ClassWriter cw;
97 private MethodVisitor mv;
98 private final List<ClassData> classData = new ArrayList<>();
99
100 /** Single element internal class name lookup cache. */
101 private Class<?> lastClass;
102 private String lastInternalName;
103
104 private static final MemberName.Factory MEMBERNAME_FACTORY = MemberName.getFactory();
105 private static final Class<?> HOST_CLASS = LambdaForm.class;
106 private static final MethodHandles.Lookup LOOKUP = lookup();
107
108 private static MethodHandles.Lookup lookup() {
109 try {
110 return MethodHandles.privateLookupIn(HOST_CLASS, IMPL_LOOKUP);
111 } catch (IllegalAccessException e) {
112 throw newInternalError(e);
113 }
114 }
115
116 /** Main constructor; other constructors delegate to this one. */
117 private InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize,
118 String name, String invokerName, MethodType invokerType) {
119 int p = invokerName.indexOf('.');
120 if (p > -1) {
121 name = invokerName.substring(0, p);
122 invokerName = invokerName.substring(p + 1);
123 }
124 if (dumper().isEnabled()) {
125 name = makeDumpableClassName(name);
126 }
127 this.name = name;
128 this.className = CLASS_PREFIX + name;
129 this.lambdaForm = lambdaForm;
130 this.invokerName = invokerName;
131 this.invokerType = invokerType;
132 this.localsMap = new int[localsMapSize+1]; // last entry of localsMap is count of allocated local slots
133 this.localClasses = new Class<?>[localsMapSize+1];
134 }
135
136 /** For generating LambdaForm interpreter entry points. */
137 private InvokerBytecodeGenerator(String name, String invokerName, MethodType invokerType) {
138 this(null, invokerType.parameterCount(),
139 name, invokerName, invokerType);
140 MethodType mt = invokerType.erase();
141 // Create an array to map name indexes to locals indexes.
142 localsMap[0] = 0; // localsMap has at least one element
143 for (int i = 1, index = 0; i < localsMap.length; i++) {
144 Wrapper w = Wrapper.forBasicType(mt.parameterType(i - 1));
145 index += w.stackSlots();
146 localsMap[i] = index;
147 }
148 }
149
150 /** For generating customized code for a single LambdaForm. */
151 private InvokerBytecodeGenerator(String name, LambdaForm form, MethodType invokerType) {
152 this(name, form.lambdaName(), form, invokerType);
153 }
154
155 /** For generating customized code for a single LambdaForm. */
156 InvokerBytecodeGenerator(String name, String invokerName,
157 LambdaForm form, MethodType invokerType) {
158 this(form, form.names.length,
159 name, invokerName, invokerType);
160 // Create an array to map name indexes to locals indexes.
161 Name[] names = form.names;
162 for (int i = 0, index = 0; i < localsMap.length; i++) {
163 localsMap[i] = index;
164 if (i < names.length) {
165 BasicType type = names[i].type();
166 index += type.basicTypeSlots();
167 }
168 }
169 }
170
171 /** instance counters for dumped classes */
172 private static final HashMap<String,Integer> DUMP_CLASS_FILES_COUNTERS =
173 dumper().isEnabled() ? new HashMap<>(): null;
174
175 private static String makeDumpableClassName(String className) {
176 Integer ctr;
177 synchronized (DUMP_CLASS_FILES_COUNTERS) {
178 ctr = DUMP_CLASS_FILES_COUNTERS.get(className);
179 if (ctr == null) ctr = 0;
180 DUMP_CLASS_FILES_COUNTERS.put(className, ctr+1);
181 }
182 String sfx = ctr.toString();
183 while (sfx.length() < 3)
184 sfx = "0" + sfx;
185 className += sfx;
186 return className;
187 }
188
189 static class ClassData {
190 final String name;
191 final String desc;
192 final Object value;
193
194 ClassData(String name, String desc, Object value) {
195 this.name = name;
196 this.desc = desc;
197 this.value = value;
198 }
199
200 public String name() { return name; }
201 public String toString() {
202 return name + ",value="+value;
203 }
204 }
205
206 String classData(Object arg) {
207 String desc;
208 if (arg instanceof Class) {
209 desc = "Ljava/lang/Class;";
210 } else if (arg instanceof MethodHandle) {
211 desc = MH_SIG;
212 } else if (arg instanceof LambdaForm) {
213 desc = LF_SIG;
214 } else {
215 desc = "Ljava/lang/Object;";
216 }
217
218 // unique static variable name
219 String name;
220 if (dumper().isEnabled()) {
221 Class<?> c = arg.getClass();
222 while (c.isArray()) {
223 c = c.getComponentType();
224 }
225 name = "_DATA_" + c.getSimpleName() + "_" + classData.size();
226 } else {
227 name = "_D_" + classData.size();
228 }
229 ClassData cd = new ClassData(name, desc, arg);
230 classData.add(cd);
231 return name;
232 }
233
234 private static String debugString(Object arg) {
235 if (arg instanceof MethodHandle mh) {
236 MemberName member = mh.internalMemberName();
237 if (member != null)
238 return member.toString();
239 return mh.debugString();
240 }
241 return arg.toString();
242 }
243
244 /**
245 * Extract the MemberName of a newly-defined method.
246 */
247 private MemberName loadMethod(byte[] classFile) {
248 Class<?> invokerClass = LOOKUP.makeHiddenClassDefiner(className, classFile, Set.of(), dumper())
249 .defineClass(true, classDataValues());
250 return resolveInvokerMember(invokerClass, invokerName, invokerType);
251 }
252
253 private static MemberName resolveInvokerMember(Class<?> invokerClass, String name, MethodType type) {
254 MemberName member = new MemberName(invokerClass, name, type, REF_invokeStatic);
255 try {
256 member = MEMBERNAME_FACTORY.resolveOrFail(REF_invokeStatic, member,
257 HOST_CLASS, LM_TRUSTED,
258 ReflectiveOperationException.class);
259 } catch (ReflectiveOperationException e) {
260 throw newInternalError(e);
261 }
262 return member;
263 }
264
265 /**
266 * Set up class file generation.
267 */
268 private ClassWriter classFilePrologue() {
269 final int NOT_ACC_PUBLIC = 0; // not ACC_PUBLIC
270 ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
271 setClassWriter(cw);
272 cw.visit(CLASSFILE_VERSION, NOT_ACC_PUBLIC + Opcodes.ACC_FINAL + Opcodes.ACC_SUPER,
273 className, null, INVOKER_SUPER_NAME, null);
274 cw.visitSource(SOURCE_PREFIX + name, null);
275 return cw;
276 }
277
278 private void methodPrologue() {
279 String invokerDesc = invokerType.toMethodDescriptorString();
280 mv = cw.visitMethod(Opcodes.ACC_STATIC, invokerName, invokerDesc, null, null);
281 }
282
283 /**
284 * Tear down class file generation.
285 */
286 private void methodEpilogue() {
287 mv.visitMaxs(0, 0);
288 mv.visitEnd();
289 }
290
291 /**
292 * Returns the class data object that will be passed to `Lookup.defineHiddenClassWithClassData`.
293 * The classData is loaded in the <clinit> method of the generated class.
294 * If the class data contains only one single object, this method returns that single object.
295 * If the class data contains more than one objects, this method returns a List.
296 *
297 * This method returns null if no class data.
298 */
299 private Object classDataValues() {
300 final List<ClassData> cd = classData;
301 return switch (cd.size()) {
302 case 0 -> null; // special case (classData is not used by <clinit>)
303 case 1 -> cd.get(0).value; // special case (single object)
304 case 2 -> List.of(cd.get(0).value, cd.get(1).value);
305 case 3 -> List.of(cd.get(0).value, cd.get(1).value, cd.get(2).value);
306 case 4 -> List.of(cd.get(0).value, cd.get(1).value, cd.get(2).value, cd.get(3).value);
307 default -> {
308 Object[] data = new Object[classData.size()];
309 for (int i = 0; i < classData.size(); i++) {
310 data[i] = classData.get(i).value;
311 }
312 yield List.of(data);
313 }
314 };
315 }
316
317 /*
318 * <clinit> to initialize the static final fields with the live class data
319 * LambdaForms can't use condy due to bootstrapping issue.
320 */
321 static void clinit(ClassWriter cw, String className, List<ClassData> classData) {
322 if (classData.isEmpty())
323 return;
324
325 for (ClassData p : classData) {
326 // add the static field
327 FieldVisitor fv = cw.visitField(Opcodes.ACC_STATIC|Opcodes.ACC_FINAL, p.name, p.desc, null, null);
328 fv.visitEnd();
329 }
330
331 MethodVisitor mv = cw.visitMethod(Opcodes.ACC_STATIC, "<clinit>", "()V", null, null);
332 mv.visitCode();
333 mv.visitLdcInsn(Type.getType("L" + className + ";"));
334 mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/invoke/MethodHandles",
335 "classData", "(Ljava/lang/Class;)Ljava/lang/Object;", false);
336 if (classData.size() == 1) {
337 ClassData p = classData.get(0);
338 mv.visitTypeInsn(Opcodes.CHECKCAST, p.desc.substring(1, p.desc.length()-1));
339 mv.visitFieldInsn(Opcodes.PUTSTATIC, className, p.name, p.desc);
340 } else {
341 mv.visitTypeInsn(Opcodes.CHECKCAST, "java/util/List");
342 mv.visitVarInsn(Opcodes.ASTORE, 0);
343 int index = 0;
344 for (ClassData p : classData) {
345 // initialize the static field
346 mv.visitVarInsn(Opcodes.ALOAD, 0);
347 emitIconstInsn(mv, index++);
348 mv.visitMethodInsn(Opcodes.INVOKEINTERFACE, "java/util/List",
349 "get", "(I)Ljava/lang/Object;", true);
350 mv.visitTypeInsn(Opcodes.CHECKCAST, p.desc.substring(1, p.desc.length()-1));
351 mv.visitFieldInsn(Opcodes.PUTSTATIC, className, p.name, p.desc);
352 }
353 }
354 mv.visitInsn(Opcodes.RETURN);
355 mv.visitMaxs(2, 1);
356 mv.visitEnd();
357 }
358
359 /*
360 * Low-level emit helpers.
361 */
362 private void emitConst(Object con) {
363 if (con == null) {
364 mv.visitInsn(Opcodes.ACONST_NULL);
365 return;
366 }
367 if (con instanceof Integer) {
368 emitIconstInsn((int) con);
369 return;
370 }
371 if (con instanceof Byte) {
372 emitIconstInsn((byte)con);
373 return;
374 }
375 if (con instanceof Short) {
376 emitIconstInsn((short)con);
377 return;
378 }
379 if (con instanceof Character) {
380 emitIconstInsn((char)con);
381 return;
382 }
383 if (con instanceof Long) {
384 long x = (long) con;
385 short sx = (short)x;
386 if (x == sx) {
387 if (sx >= 0 && sx <= 1) {
388 mv.visitInsn(Opcodes.LCONST_0 + (int) sx);
389 } else {
390 emitIconstInsn((int) x);
391 mv.visitInsn(Opcodes.I2L);
392 }
393 return;
394 }
395 }
396 if (con instanceof Float) {
397 float x = (float) con;
398 short sx = (short)x;
399 if (x == sx) {
400 if (sx >= 0 && sx <= 2) {
401 mv.visitInsn(Opcodes.FCONST_0 + (int) sx);
402 } else {
403 emitIconstInsn((int) x);
404 mv.visitInsn(Opcodes.I2F);
405 }
406 return;
407 }
408 }
409 if (con instanceof Double) {
410 double x = (double) con;
411 short sx = (short)x;
412 if (x == sx) {
413 if (sx >= 0 && sx <= 1) {
414 mv.visitInsn(Opcodes.DCONST_0 + (int) sx);
415 } else {
416 emitIconstInsn((int) x);
417 mv.visitInsn(Opcodes.I2D);
418 }
419 return;
420 }
421 }
422 if (con instanceof Boolean) {
423 emitIconstInsn((boolean) con ? 1 : 0);
424 return;
425 }
426 // fall through:
427 mv.visitLdcInsn(con);
428 }
429
430 private void emitIconstInsn(final int cst) {
431 emitIconstInsn(mv, cst);
432 }
433
434 private static void emitIconstInsn(MethodVisitor mv, int cst) {
435 if (cst >= -1 && cst <= 5) {
436 mv.visitInsn(Opcodes.ICONST_0 + cst);
437 } else if (cst >= Byte.MIN_VALUE && cst <= Byte.MAX_VALUE) {
438 mv.visitIntInsn(Opcodes.BIPUSH, cst);
439 } else if (cst >= Short.MIN_VALUE && cst <= Short.MAX_VALUE) {
440 mv.visitIntInsn(Opcodes.SIPUSH, cst);
441 } else {
442 mv.visitLdcInsn(cst);
443 }
444 }
445
446 /*
447 * NOTE: These load/store methods use the localsMap to find the correct index!
448 */
449 private void emitLoadInsn(BasicType type, int index) {
450 int opcode = loadInsnOpcode(type);
451 mv.visitVarInsn(opcode, localsMap[index]);
452 }
453
454 private int loadInsnOpcode(BasicType type) throws InternalError {
455 return switch (type) {
456 case I_TYPE -> Opcodes.ILOAD;
457 case J_TYPE -> Opcodes.LLOAD;
458 case F_TYPE -> Opcodes.FLOAD;
459 case D_TYPE -> Opcodes.DLOAD;
460 case L_TYPE -> Opcodes.ALOAD;
461 default -> throw new InternalError("unknown type: " + type);
462 };
463 }
464 private void emitAloadInsn(int index) {
465 emitLoadInsn(L_TYPE, index);
466 }
467
468 private void emitStoreInsn(BasicType type, int index) {
469 int opcode = storeInsnOpcode(type);
470 mv.visitVarInsn(opcode, localsMap[index]);
471 }
472
473 private int storeInsnOpcode(BasicType type) throws InternalError {
474 return switch (type) {
475 case I_TYPE -> Opcodes.ISTORE;
476 case J_TYPE -> Opcodes.LSTORE;
477 case F_TYPE -> Opcodes.FSTORE;
478 case D_TYPE -> Opcodes.DSTORE;
479 case L_TYPE -> Opcodes.ASTORE;
480 default -> throw new InternalError("unknown type: " + type);
481 };
482 }
483 private void emitAstoreInsn(int index) {
484 emitStoreInsn(L_TYPE, index);
485 }
486
487 private byte arrayTypeCode(Wrapper elementType) {
488 return (byte) switch (elementType) {
489 case BOOLEAN -> Opcodes.T_BOOLEAN;
490 case BYTE -> Opcodes.T_BYTE;
491 case CHAR -> Opcodes.T_CHAR;
492 case SHORT -> Opcodes.T_SHORT;
493 case INT -> Opcodes.T_INT;
494 case LONG -> Opcodes.T_LONG;
495 case FLOAT -> Opcodes.T_FLOAT;
496 case DOUBLE -> Opcodes.T_DOUBLE;
497 case OBJECT -> 0; // in place of Opcodes.T_OBJECT
498 default -> throw new InternalError();
499 };
500 }
501
502 private int arrayInsnOpcode(byte tcode, int aaop) throws InternalError {
503 assert(aaop == Opcodes.AASTORE || aaop == Opcodes.AALOAD);
504 int xas = switch (tcode) {
505 case Opcodes.T_BOOLEAN -> Opcodes.BASTORE;
506 case Opcodes.T_BYTE -> Opcodes.BASTORE;
507 case Opcodes.T_CHAR -> Opcodes.CASTORE;
508 case Opcodes.T_SHORT -> Opcodes.SASTORE;
509 case Opcodes.T_INT -> Opcodes.IASTORE;
510 case Opcodes.T_LONG -> Opcodes.LASTORE;
511 case Opcodes.T_FLOAT -> Opcodes.FASTORE;
512 case Opcodes.T_DOUBLE -> Opcodes.DASTORE;
513 case 0 -> Opcodes.AASTORE;
514 default -> throw new InternalError();
515 };
516 return xas - Opcodes.AASTORE + aaop;
517 }
518
519 /**
520 * Emit a boxing call.
521 *
522 * @param wrapper primitive type class to box.
523 */
524 private void emitBoxing(Wrapper wrapper) {
525 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
526 String name = "valueOf";
527 String desc = "(" + wrapper.basicTypeChar() + ")L" + owner + ";";
528 mv.visitMethodInsn(Opcodes.INVOKESTATIC, owner, name, desc, false);
529 }
530
531 /**
532 * Emit an unboxing call (plus preceding checkcast).
533 *
534 * @param wrapper wrapper type class to unbox.
535 */
536 private void emitUnboxing(Wrapper wrapper) {
537 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
538 String name = wrapper.primitiveSimpleName() + "Value";
539 String desc = "()" + wrapper.basicTypeChar();
540 emitReferenceCast(wrapper.wrapperType(), null);
541 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, owner, name, desc, false);
542 }
543
544 /**
545 * Emit an implicit conversion for an argument which must be of the given pclass.
546 * This is usually a no-op, except when pclass is a subword type or a reference other than Object or an interface.
547 *
548 * @param ptype type of value present on stack
549 * @param pclass type of value required on stack
550 * @param arg compile-time representation of value on stack (Node, constant) or null if none
551 */
552 private void emitImplicitConversion(BasicType ptype, Class<?> pclass, Object arg) {
553 assert(basicType(pclass) == ptype); // boxing/unboxing handled by caller
554 if (pclass == ptype.basicTypeClass() && ptype != L_TYPE)
555 return; // nothing to do
556 switch (ptype) {
557 case L_TYPE:
558 if (VerifyType.isNullConversion(Object.class, pclass, false)) {
559 if (PROFILE_LEVEL > 0)
560 emitReferenceCast(Object.class, arg);
561 return;
562 }
563 emitReferenceCast(pclass, arg);
564 return;
565 case I_TYPE:
566 if (!VerifyType.isNullConversion(int.class, pclass, false))
567 emitPrimCast(ptype.basicTypeWrapper(), Wrapper.forPrimitiveType(pclass));
568 return;
569 }
570 throw newInternalError("bad implicit conversion: tc="+ptype+": "+pclass);
571 }
572
573 /** Update localClasses type map. Return true if the information is already present. */
574 private boolean assertStaticType(Class<?> cls, Name n) {
575 int local = n.index();
576 Class<?> aclass = localClasses[local];
577 if (aclass != null && (aclass == cls || cls.isAssignableFrom(aclass))) {
578 return true; // type info is already present
579 } else if (aclass == null || aclass.isAssignableFrom(cls)) {
580 localClasses[local] = cls; // type info can be improved
581 }
582 return false;
583 }
584
585 private void emitReferenceCast(Class<?> cls, Object arg) {
586 Name writeBack = null; // local to write back result
587 if (arg instanceof Name n) {
588 if (lambdaForm.useCount(n) > 1) {
589 // This guy gets used more than once.
590 writeBack = n;
591 if (assertStaticType(cls, n)) {
592 return; // this cast was already performed
593 }
594 }
595 }
596 if (isStaticallyNameable(cls)) {
597 String sig = getInternalName(cls);
598 mv.visitTypeInsn(Opcodes.CHECKCAST, sig);
599 } else {
600 mv.visitFieldInsn(Opcodes.GETSTATIC, className, classData(cls), "Ljava/lang/Class;");
601 mv.visitInsn(Opcodes.SWAP);
602 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, CLS, "cast", LL_SIG, false);
603 if (Object[].class.isAssignableFrom(cls))
604 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJARY);
605 else if (PROFILE_LEVEL > 0)
606 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJ);
607 }
608 if (writeBack != null) {
609 mv.visitInsn(Opcodes.DUP);
610 emitAstoreInsn(writeBack.index());
611 }
612 }
613
614 /**
615 * Emits an actual return instruction conforming to the given return type.
616 */
617 private void emitReturnInsn(BasicType type) {
618 int opcode = switch (type) {
619 case I_TYPE -> Opcodes.IRETURN;
620 case J_TYPE -> Opcodes.LRETURN;
621 case F_TYPE -> Opcodes.FRETURN;
622 case D_TYPE -> Opcodes.DRETURN;
623 case L_TYPE -> Opcodes.ARETURN;
624 case V_TYPE -> Opcodes.RETURN;
625 default -> throw new InternalError("unknown return type: " + type);
626 };
627 mv.visitInsn(opcode);
628 }
629
630 private String getInternalName(Class<?> c) {
631 if (c == Object.class) return OBJ;
632 else if (c == Object[].class) return OBJARY;
633 else if (c == Class.class) return CLS;
634 else if (c == MethodHandle.class) return MH;
635 assert(VerifyAccess.isTypeVisible(c, Object.class)) : c.getName();
636
637 if (c == lastClass) {
638 return lastInternalName;
639 }
640 lastClass = c;
641 return lastInternalName = c.getName().replace('.', '/');
642 }
643
644 private static MemberName resolveFrom(String name, MethodType type, Class<?> holder) {
645 assert(!UNSAFE.shouldBeInitialized(holder)) : holder + "not initialized";
646 MemberName member = new MemberName(holder, name, type, REF_invokeStatic);
647 MemberName resolvedMember = MemberName.getFactory().resolveOrNull(REF_invokeStatic, member, holder, LM_TRUSTED);
648 traceLambdaForm(name, type, holder, resolvedMember);
649 return resolvedMember;
650 }
651
652 private static MemberName lookupPregenerated(LambdaForm form, MethodType invokerType) {
653 if (form.customized != null) {
654 // No pre-generated version for customized LF
655 return null;
656 }
657 String name = form.kind.methodName;
658 switch (form.kind) {
659 case BOUND_REINVOKER: {
660 name = name + "_" + BoundMethodHandle.speciesDataFor(form).key();
661 return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class);
662 }
663 case DELEGATE: return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class);
664 case ZERO: // fall-through
665 case IDENTITY: {
666 name = name + "_" + form.returnType().basicTypeChar();
667 return resolveFrom(name, invokerType, LambdaForm.Holder.class);
668 }
669 case EXACT_INVOKER: // fall-through
670 case EXACT_LINKER: // fall-through
671 case LINK_TO_CALL_SITE: // fall-through
672 case LINK_TO_TARGET_METHOD: // fall-through
673 case GENERIC_INVOKER: // fall-through
674 case GENERIC_LINKER: return resolveFrom(name, invokerType, Invokers.Holder.class);
675 case GET_REFERENCE: // fall-through
676 case GET_BOOLEAN: // fall-through
677 case GET_BYTE: // fall-through
678 case GET_CHAR: // fall-through
679 case GET_SHORT: // fall-through
680 case GET_INT: // fall-through
681 case GET_LONG: // fall-through
682 case GET_FLOAT: // fall-through
683 case GET_DOUBLE: // fall-through
684 case PUT_REFERENCE: // fall-through
685 case PUT_BOOLEAN: // fall-through
686 case PUT_BYTE: // fall-through
687 case PUT_CHAR: // fall-through
688 case PUT_SHORT: // fall-through
689 case PUT_INT: // fall-through
690 case PUT_LONG: // fall-through
691 case PUT_FLOAT: // fall-through
692 case PUT_DOUBLE: // fall-through
693 case DIRECT_NEW_INVOKE_SPECIAL: // fall-through
694 case DIRECT_INVOKE_INTERFACE: // fall-through
695 case DIRECT_INVOKE_SPECIAL: // fall-through
696 case DIRECT_INVOKE_SPECIAL_IFC: // fall-through
697 case DIRECT_INVOKE_STATIC: // fall-through
698 case DIRECT_INVOKE_STATIC_INIT: // fall-through
699 case DIRECT_INVOKE_VIRTUAL: return resolveFrom(name, invokerType, DirectMethodHandle.Holder.class);
700 }
701 return null;
702 }
703
704 /**
705 * Generate customized bytecode for a given LambdaForm.
706 */
707 static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) {
708 MemberName pregenerated = lookupPregenerated(form, invokerType);
709 if (pregenerated != null) return pregenerated; // pre-generated bytecode
710
711 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("MH", form, invokerType);
712 return g.loadMethod(g.generateCustomizedCodeBytes());
713 }
714
715 /** Generates code to check that actual receiver and LambdaForm matches */
716 private boolean checkActualReceiver() {
717 // Expects MethodHandle on the stack and actual receiver MethodHandle in slot #0
718 mv.visitInsn(Opcodes.DUP);
719 mv.visitVarInsn(Opcodes.ALOAD, localsMap[0]);
720 mv.visitMethodInsn(Opcodes.INVOKESTATIC, MHI, "assertSame", LLV_SIG, false);
721 return true;
722 }
723
724 static String className(String cn) {
725 assert checkClassName(cn): "Class not found: " + cn;
726 return cn;
727 }
728
729 static boolean checkClassName(String cn) {
730 Type tp = Type.getType(cn);
731 // additional sanity so only valid "L;" descriptors work
732 if (tp.getSort() != Type.OBJECT) {
733 return false;
734 }
735 try {
736 Class<?> c = Class.forName(tp.getClassName(), false, null);
737 return true;
738 } catch (ClassNotFoundException e) {
739 return false;
740 }
741 }
742
743 static final String DONTINLINE_SIG = className("Ljdk/internal/vm/annotation/DontInline;");
744 static final String FORCEINLINE_SIG = className("Ljdk/internal/vm/annotation/ForceInline;");
745 static final String HIDDEN_SIG = className("Ljdk/internal/vm/annotation/Hidden;");
746 static final String INJECTEDPROFILE_SIG = className("Ljava/lang/invoke/InjectedProfile;");
747 static final String LF_COMPILED_SIG = className("Ljava/lang/invoke/LambdaForm$Compiled;");
748
749 /**
750 * Generate an invoker method for the passed {@link LambdaForm}.
751 */
752 private byte[] generateCustomizedCodeBytes() {
753 classFilePrologue();
754 addMethod();
755 clinit(cw, className, classData);
756 bogusMethod(lambdaForm);
757
758 return toByteArray();
759 }
760
761 void setClassWriter(ClassWriter cw) {
762 this.cw = cw;
763 }
764
765 void addMethod() {
766 methodPrologue();
767
768 // Suppress this method in backtraces displayed to the user.
769 mv.visitAnnotation(HIDDEN_SIG, true);
770
771 // Mark this method as a compiled LambdaForm
772 mv.visitAnnotation(LF_COMPILED_SIG, true);
773
774 if (lambdaForm.forceInline) {
775 // Force inlining of this invoker method.
776 mv.visitAnnotation(FORCEINLINE_SIG, true);
777 } else {
778 mv.visitAnnotation(DONTINLINE_SIG, true);
779 }
780
781 classData(lambdaForm); // keep LambdaForm instance & its compiled form lifetime tightly coupled.
782
783 if (lambdaForm.customized != null) {
784 // Since LambdaForm is customized for a particular MethodHandle, it's safe to substitute
785 // receiver MethodHandle (at slot #0) with an embedded constant and use it instead.
786 // It enables more efficient code generation in some situations, since embedded constants
787 // are compile-time constants for JIT compiler.
788 mv.visitFieldInsn(Opcodes.GETSTATIC, className, classData(lambdaForm.customized), MH_SIG);
789 mv.visitTypeInsn(Opcodes.CHECKCAST, MH);
790 assert(checkActualReceiver()); // expects MethodHandle on top of the stack
791 mv.visitVarInsn(Opcodes.ASTORE, localsMap[0]);
792 }
793
794 // iterate over the form's names, generating bytecode instructions for each
795 // start iterating at the first name following the arguments
796 Name onStack = null;
797 for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) {
798 Name name = lambdaForm.names[i];
799
800 emitStoreResult(onStack);
801 onStack = name; // unless otherwise modified below
802 MethodHandleImpl.Intrinsic intr = name.function.intrinsicName();
803 switch (intr) {
804 case SELECT_ALTERNATIVE:
805 assert lambdaForm.isSelectAlternative(i);
806 if (PROFILE_GWT) {
807 assert(name.arguments[0] instanceof Name n &&
808 n.refersTo(MethodHandleImpl.class, "profileBoolean"));
809 mv.visitAnnotation(INJECTEDPROFILE_SIG, true);
810 }
811 onStack = emitSelectAlternative(name, lambdaForm.names[i+1]);
812 i++; // skip MH.invokeBasic of the selectAlternative result
813 continue;
814 case GUARD_WITH_CATCH:
815 assert lambdaForm.isGuardWithCatch(i);
816 onStack = emitGuardWithCatch(i);
817 i += 2; // jump to the end of GWC idiom
818 continue;
819 case TRY_FINALLY:
820 assert lambdaForm.isTryFinally(i);
821 onStack = emitTryFinally(i);
822 i += 2; // jump to the end of the TF idiom
823 continue;
824 case TABLE_SWITCH:
825 assert lambdaForm.isTableSwitch(i);
826 int numCases = (Integer) name.function.intrinsicData();
827 onStack = emitTableSwitch(i, numCases);
828 i += 2; // jump to the end of the TS idiom
829 continue;
830 case LOOP:
831 assert lambdaForm.isLoop(i);
832 onStack = emitLoop(i);
833 i += 2; // jump to the end of the LOOP idiom
834 continue;
835 case ARRAY_LOAD:
836 emitArrayLoad(name);
837 continue;
838 case ARRAY_STORE:
839 emitArrayStore(name);
840 continue;
841 case ARRAY_LENGTH:
842 emitArrayLength(name);
843 continue;
844 case IDENTITY:
845 assert(name.arguments.length == 1);
846 emitPushArguments(name, 0);
847 continue;
848 case ZERO:
849 assert(name.arguments.length == 0);
850 emitConst(name.type.basicTypeWrapper().zero());
851 continue;
852 case NONE:
853 // no intrinsic associated
854 break;
855 default:
856 throw newInternalError("Unknown intrinsic: "+intr);
857 }
858
859 MemberName member = name.function.member();
860 if (isStaticallyInvocable(member)) {
861 emitStaticInvoke(member, name);
862 } else {
863 emitInvoke(name);
864 }
865 }
866
867 // return statement
868 emitReturn(onStack);
869
870 methodEpilogue();
871 }
872
873 /*
874 * @throws BytecodeGenerationException if something goes wrong when
875 * generating the byte code
876 */
877 private byte[] toByteArray() {
878 try {
879 return cw.toByteArray();
880 } catch (RuntimeException e) {
881 throw new BytecodeGenerationException(e);
882 }
883 }
884
885 /**
886 * The BytecodeGenerationException.
887 */
888 @SuppressWarnings("serial")
889 static final class BytecodeGenerationException extends RuntimeException {
890 BytecodeGenerationException(Exception cause) {
891 super(cause);
892 }
893 }
894
895 void emitArrayLoad(Name name) { emitArrayOp(name, Opcodes.AALOAD); }
896 void emitArrayStore(Name name) { emitArrayOp(name, Opcodes.AASTORE); }
897 void emitArrayLength(Name name) { emitArrayOp(name, Opcodes.ARRAYLENGTH); }
898
899 void emitArrayOp(Name name, int arrayOpcode) {
900 assert arrayOpcode == Opcodes.AALOAD || arrayOpcode == Opcodes.AASTORE || arrayOpcode == Opcodes.ARRAYLENGTH;
901 Class<?> elementType = name.function.methodType().parameterType(0).getComponentType();
902 assert elementType != null;
903 emitPushArguments(name, 0);
904 if (arrayOpcode != Opcodes.ARRAYLENGTH && elementType.isPrimitive()) {
905 Wrapper w = Wrapper.forPrimitiveType(elementType);
906 arrayOpcode = arrayInsnOpcode(arrayTypeCode(w), arrayOpcode);
907 }
908 mv.visitInsn(arrayOpcode);
909 }
910
911 /**
912 * Emit an invoke for the given name.
913 */
914 void emitInvoke(Name name) {
915 assert(!name.isLinkerMethodInvoke()); // should use the static path for these
916 if (true) {
917 // push receiver
918 MethodHandle target = name.function.resolvedHandle();
919 assert(target != null) : name.exprString();
920 mv.visitFieldInsn(Opcodes.GETSTATIC, className, classData(target), MH_SIG);
921 emitReferenceCast(MethodHandle.class, target);
922 } else {
923 // load receiver
924 emitAloadInsn(0);
925 emitReferenceCast(MethodHandle.class, null);
926 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", LF_SIG);
927 mv.visitFieldInsn(Opcodes.GETFIELD, LF, "names", LFN_SIG);
928 // TODO more to come
929 }
930
931 // push arguments
932 emitPushArguments(name, 0);
933
934 // invocation
935 MethodType type = name.function.methodType();
936 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
937 }
938
939 private static final Class<?>[] STATICALLY_INVOCABLE_PACKAGES = {
940 // Sample classes from each package we are willing to bind to statically:
941 java.lang.Object.class,
942 java.util.Arrays.class,
943 jdk.internal.misc.Unsafe.class
944 //MethodHandle.class already covered
945 };
946
947 static boolean isStaticallyInvocable(NamedFunction ... functions) {
948 for (NamedFunction nf : functions) {
949 if (!isStaticallyInvocable(nf.member())) {
950 return false;
951 }
952 }
953 return true;
954 }
955
956 static boolean isStaticallyInvocable(Name name) {
957 return isStaticallyInvocable(name.function.member());
958 }
959
960 static boolean isStaticallyInvocable(MemberName member) {
961 if (member == null) return false;
962 if (member.isConstructor()) return false;
963 Class<?> cls = member.getDeclaringClass();
964 // Fast-path non-private members declared by MethodHandles, which is a common
965 // case
966 if (MethodHandle.class.isAssignableFrom(cls) && !member.isPrivate()) {
967 assert(isStaticallyInvocableType(member.getMethodOrFieldType()));
968 return true;
969 }
970 if (cls.isArray() || cls.isPrimitive())
971 return false; // FIXME
972 if (cls.isAnonymousClass() || cls.isLocalClass())
973 return false; // inner class of some sort
974 if (cls.getClassLoader() != MethodHandle.class.getClassLoader())
975 return false; // not on BCP
976 if (cls.isHidden())
977 return false;
978 if (!isStaticallyInvocableType(member.getMethodOrFieldType()))
979 return false;
980 if (!member.isPrivate() && VerifyAccess.isSamePackage(MethodHandle.class, cls))
981 return true; // in java.lang.invoke package
982 if (member.isPublic() && isStaticallyNameable(cls))
983 return true;
984 return false;
985 }
986
987 private static boolean isStaticallyInvocableType(MethodType mtype) {
988 if (!isStaticallyNameable(mtype.returnType()))
989 return false;
990 for (Class<?> ptype : mtype.ptypes())
991 if (!isStaticallyNameable(ptype))
992 return false;
993 return true;
994 }
995
996 static boolean isStaticallyNameable(Class<?> cls) {
997 if (cls == Object.class)
998 return true;
999 if (MethodHandle.class.isAssignableFrom(cls)) {
1000 assert(!cls.isHidden());
1001 return true;
1002 }
1003 while (cls.isArray())
1004 cls = cls.getComponentType();
1005 if (cls.isPrimitive())
1006 return true; // int[].class, for example
1007 if (cls.isHidden())
1008 return false;
1009 // could use VerifyAccess.isClassAccessible but the following is a safe approximation
1010 if (cls.getClassLoader() != Object.class.getClassLoader())
1011 return false;
1012 if (VerifyAccess.isSamePackage(MethodHandle.class, cls))
1013 return true;
1014 if (!Modifier.isPublic(cls.getModifiers()))
1015 return false;
1016 for (Class<?> pkgcls : STATICALLY_INVOCABLE_PACKAGES) {
1017 if (VerifyAccess.isSamePackage(pkgcls, cls))
1018 return true;
1019 }
1020 return false;
1021 }
1022
1023 void emitStaticInvoke(Name name) {
1024 emitStaticInvoke(name.function.member(), name);
1025 }
1026
1027 /**
1028 * Emit an invoke for the given name, using the MemberName directly.
1029 */
1030 void emitStaticInvoke(MemberName member, Name name) {
1031 assert(member.equals(name.function.member()));
1032 Class<?> defc = member.getDeclaringClass();
1033 String cname = getInternalName(defc);
1034 String mname = member.getName();
1035 String mtype;
1036 byte refKind = member.getReferenceKind();
1037 if (refKind == REF_invokeSpecial) {
1038 // in order to pass the verifier, we need to convert this to invokevirtual in all cases
1039 assert(member.canBeStaticallyBound()) : member;
1040 refKind = REF_invokeVirtual;
1041 }
1042
1043 assert(!(member.getDeclaringClass().isInterface() && refKind == REF_invokeVirtual));
1044
1045 // push arguments
1046 emitPushArguments(name, 0);
1047
1048 // invocation
1049 if (member.isMethod()) {
1050 mtype = member.getMethodType().toMethodDescriptorString();
1051 mv.visitMethodInsn(refKindOpcode(refKind), cname, mname, mtype,
1052 member.getDeclaringClass().isInterface());
1053 } else {
1054 mtype = MethodType.toFieldDescriptorString(member.getFieldType());
1055 mv.visitFieldInsn(refKindOpcode(refKind), cname, mname, mtype);
1056 }
1057 // Issue a type assertion for the result, so we can avoid casts later.
1058 if (name.type == L_TYPE) {
1059 Class<?> rtype = member.getInvocationType().returnType();
1060 assert(!rtype.isPrimitive());
1061 if (rtype != Object.class && !rtype.isInterface()) {
1062 assertStaticType(rtype, name);
1063 }
1064 }
1065 }
1066
1067 int refKindOpcode(byte refKind) {
1068 switch (refKind) {
1069 case REF_invokeVirtual: return Opcodes.INVOKEVIRTUAL;
1070 case REF_invokeStatic: return Opcodes.INVOKESTATIC;
1071 case REF_invokeSpecial: return Opcodes.INVOKESPECIAL;
1072 case REF_invokeInterface: return Opcodes.INVOKEINTERFACE;
1073 case REF_getField: return Opcodes.GETFIELD;
1074 case REF_putField: return Opcodes.PUTFIELD;
1075 case REF_getStatic: return Opcodes.GETSTATIC;
1076 case REF_putStatic: return Opcodes.PUTSTATIC;
1077 }
1078 throw new InternalError("refKind="+refKind);
1079 }
1080
1081 /**
1082 * Emit bytecode for the selectAlternative idiom.
1083 *
1084 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithTest):
1085 * <blockquote><pre>{@code
1086 * Lambda(a0:L,a1:I)=>{
1087 * t2:I=foo.test(a1:I);
1088 * t3:L=MethodHandleImpl.selectAlternative(t2:I,(MethodHandle(int)int),(MethodHandle(int)int));
1089 * t4:I=MethodHandle.invokeBasic(t3:L,a1:I);t4:I}
1090 * }</pre></blockquote>
1091 */
1092 private Name emitSelectAlternative(Name selectAlternativeName, Name invokeBasicName) {
1093 assert isStaticallyInvocable(invokeBasicName);
1094
1095 Name receiver = (Name) invokeBasicName.arguments[0];
1096
1097 Label L_fallback = new Label();
1098 Label L_done = new Label();
1099
1100 // load test result
1101 emitPushArgument(selectAlternativeName, 0);
1102
1103 // if_icmpne L_fallback
1104 mv.visitJumpInsn(Opcodes.IFEQ, L_fallback);
1105
1106 // invoke selectAlternativeName.arguments[1]
1107 Class<?>[] preForkClasses = localClasses.clone();
1108 emitPushArgument(selectAlternativeName, 1); // get 2nd argument of selectAlternative
1109 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
1110 emitStaticInvoke(invokeBasicName);
1111
1112 // goto L_done
1113 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1114
1115 // L_fallback:
1116 mv.visitLabel(L_fallback);
1117
1118 // invoke selectAlternativeName.arguments[2]
1119 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
1120 emitPushArgument(selectAlternativeName, 2); // get 3rd argument of selectAlternative
1121 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
1122 emitStaticInvoke(invokeBasicName);
1123
1124 // L_done:
1125 mv.visitLabel(L_done);
1126 // for now do not bother to merge typestate; just reset to the dominator state
1127 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
1128
1129 return invokeBasicName; // return what's on stack
1130 }
1131
1132 /**
1133 * Emit bytecode for the guardWithCatch idiom.
1134 *
1135 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithCatch):
1136 * <blockquote><pre>{@code
1137 * guardWithCatch=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{
1138 * t8:L=MethodHandle.invokeBasic(a4:L,a6:L,a7:L);
1139 * t9:L=MethodHandleImpl.guardWithCatch(a1:L,a2:L,a3:L,t8:L);
1140 * t10:I=MethodHandle.invokeBasic(a5:L,t9:L);t10:I}
1141 * }</pre></blockquote>
1142 *
1143 * It is compiled into bytecode equivalent of the following code:
1144 * <blockquote><pre>{@code
1145 * try {
1146 * return a1.invokeBasic(a6, a7);
1147 * } catch (Throwable e) {
1148 * if (!a2.isInstance(e)) throw e;
1149 * return a3.invokeBasic(ex, a6, a7);
1150 * }}</pre></blockquote>
1151 */
1152 private Name emitGuardWithCatch(int pos) {
1153 Name args = lambdaForm.names[pos];
1154 Name invoker = lambdaForm.names[pos+1];
1155 Name result = lambdaForm.names[pos+2];
1156
1157 Label L_startBlock = new Label();
1158 Label L_endBlock = new Label();
1159 Label L_handler = new Label();
1160 Label L_done = new Label();
1161
1162 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1163 MethodType type = args.function.resolvedHandle().type()
1164 .dropParameterTypes(0,1)
1165 .changeReturnType(returnType);
1166
1167 mv.visitTryCatchBlock(L_startBlock, L_endBlock, L_handler, "java/lang/Throwable");
1168
1169 // Normal case
1170 mv.visitLabel(L_startBlock);
1171 // load target
1172 emitPushArgument(invoker, 0);
1173 emitPushArguments(args, 1); // skip 1st argument: method handle
1174 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
1175 mv.visitLabel(L_endBlock);
1176 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1177
1178 // Exceptional case
1179 mv.visitLabel(L_handler);
1180
1181 // Check exception's type
1182 mv.visitInsn(Opcodes.DUP);
1183 // load exception class
1184 emitPushArgument(invoker, 1);
1185 mv.visitInsn(Opcodes.SWAP);
1186 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Class", "isInstance", "(Ljava/lang/Object;)Z", false);
1187 Label L_rethrow = new Label();
1188 mv.visitJumpInsn(Opcodes.IFEQ, L_rethrow);
1189
1190 // Invoke catcher
1191 // load catcher
1192 emitPushArgument(invoker, 2);
1193 mv.visitInsn(Opcodes.SWAP);
1194 emitPushArguments(args, 1); // skip 1st argument: method handle
1195 MethodType catcherType = type.insertParameterTypes(0, Throwable.class);
1196 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", catcherType.basicType().toMethodDescriptorString(), false);
1197 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1198
1199 mv.visitLabel(L_rethrow);
1200 mv.visitInsn(Opcodes.ATHROW);
1201
1202 mv.visitLabel(L_done);
1203
1204 return result;
1205 }
1206
1207 /**
1208 * Emit bytecode for the tryFinally idiom.
1209 * <p>
1210 * The pattern looks like (Cf. MethodHandleImpl.makeTryFinally):
1211 * <blockquote><pre>{@code
1212 * // a0: BMH
1213 * // a1: target, a2: cleanup
1214 * // a3: box, a4: unbox
1215 * // a5 (and following): arguments
1216 * tryFinally=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L)=>{
1217 * t6:L=MethodHandle.invokeBasic(a3:L,a5:L); // box the arguments into an Object[]
1218 * t7:L=MethodHandleImpl.tryFinally(a1:L,a2:L,t6:L); // call the tryFinally executor
1219 * t8:L=MethodHandle.invokeBasic(a4:L,t7:L);t8:L} // unbox the result; return the result
1220 * }</pre></blockquote>
1221 * <p>
1222 * It is compiled into bytecode equivalent to the following code:
1223 * <blockquote><pre>{@code
1224 * Throwable t;
1225 * Object r;
1226 * try {
1227 * r = a1.invokeBasic(a5);
1228 * } catch (Throwable thrown) {
1229 * t = thrown;
1230 * throw t;
1231 * } finally {
1232 * r = a2.invokeBasic(t, r, a5);
1233 * }
1234 * return r;
1235 * }</pre></blockquote>
1236 * <p>
1237 * Specifically, the bytecode will have the following form (the stack effects are given for the beginnings of
1238 * blocks, and for the situations after executing the given instruction - the code will have a slightly different
1239 * shape if the return type is {@code void}):
1240 * <blockquote><pre>{@code
1241 * TRY: (--)
1242 * load target (-- target)
1243 * load args (-- args... target)
1244 * INVOKEVIRTUAL MethodHandle.invokeBasic (depends)
1245 * FINALLY_NORMAL: (-- r_2nd* r)
1246 * store returned value (--)
1247 * load cleanup (-- cleanup)
1248 * ACONST_NULL (-- t cleanup)
1249 * load returned value (-- r_2nd* r t cleanup)
1250 * load args (-- args... r_2nd* r t cleanup)
1251 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r_2nd* r)
1252 * GOTO DONE
1253 * CATCH: (-- t)
1254 * DUP (-- t t)
1255 * FINALLY_EXCEPTIONAL: (-- t t)
1256 * load cleanup (-- cleanup t t)
1257 * SWAP (-- t cleanup t)
1258 * load default for r (-- r_2nd* r t cleanup t)
1259 * load args (-- args... r_2nd* r t cleanup t)
1260 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r_2nd* r t)
1261 * POP/POP2* (-- t)
1262 * ATHROW
1263 * DONE: (-- r)
1264 * }</pre></blockquote>
1265 * * = depends on whether the return type takes up 2 stack slots.
1266 */
1267 private Name emitTryFinally(int pos) {
1268 Name args = lambdaForm.names[pos];
1269 Name invoker = lambdaForm.names[pos+1];
1270 Name result = lambdaForm.names[pos+2];
1271
1272 Label lFrom = new Label();
1273 Label lTo = new Label();
1274 Label lCatch = new Label();
1275 Label lDone = new Label();
1276
1277 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1278 BasicType basicReturnType = BasicType.basicType(returnType);
1279 boolean isNonVoid = returnType != void.class;
1280
1281 MethodType type = args.function.resolvedHandle().type()
1282 .dropParameterTypes(0,1)
1283 .changeReturnType(returnType);
1284 MethodType cleanupType = type.insertParameterTypes(0, Throwable.class);
1285 if (isNonVoid) {
1286 cleanupType = cleanupType.insertParameterTypes(1, returnType);
1287 }
1288 String cleanupDesc = cleanupType.basicType().toMethodDescriptorString();
1289
1290 // exception handler table
1291 mv.visitTryCatchBlock(lFrom, lTo, lCatch, "java/lang/Throwable");
1292
1293 // TRY:
1294 mv.visitLabel(lFrom);
1295 emitPushArgument(invoker, 0); // load target
1296 emitPushArguments(args, 1); // load args (skip 0: method handle)
1297 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
1298 mv.visitLabel(lTo);
1299
1300 // FINALLY_NORMAL:
1301 int index = extendLocalsMap(new Class<?>[]{ returnType });
1302 if (isNonVoid) {
1303 emitStoreInsn(basicReturnType, index);
1304 }
1305 emitPushArgument(invoker, 1); // load cleanup
1306 mv.visitInsn(Opcodes.ACONST_NULL);
1307 if (isNonVoid) {
1308 emitLoadInsn(basicReturnType, index);
1309 }
1310 emitPushArguments(args, 1); // load args (skip 0: method handle)
1311 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", cleanupDesc, false);
1312 mv.visitJumpInsn(Opcodes.GOTO, lDone);
1313
1314 // CATCH:
1315 mv.visitLabel(lCatch);
1316 mv.visitInsn(Opcodes.DUP);
1317
1318 // FINALLY_EXCEPTIONAL:
1319 emitPushArgument(invoker, 1); // load cleanup
1320 mv.visitInsn(Opcodes.SWAP);
1321 if (isNonVoid) {
1322 emitZero(BasicType.basicType(returnType)); // load default for result
1323 }
1324 emitPushArguments(args, 1); // load args (skip 0: method handle)
1325 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", cleanupDesc, false);
1326 if (isNonVoid) {
1327 emitPopInsn(basicReturnType);
1328 }
1329 mv.visitInsn(Opcodes.ATHROW);
1330
1331 // DONE:
1332 mv.visitLabel(lDone);
1333
1334 return result;
1335 }
1336
1337 private void emitPopInsn(BasicType type) {
1338 mv.visitInsn(popInsnOpcode(type));
1339 }
1340
1341 private static int popInsnOpcode(BasicType type) {
1342 return switch (type) {
1343 case I_TYPE, F_TYPE, L_TYPE -> Opcodes.POP;
1344 case J_TYPE, D_TYPE -> Opcodes.POP2;
1345 default -> throw new InternalError("unknown type: " + type);
1346 };
1347 }
1348
1349 private Name emitTableSwitch(int pos, int numCases) {
1350 Name args = lambdaForm.names[pos];
1351 Name invoker = lambdaForm.names[pos + 1];
1352 Name result = lambdaForm.names[pos + 2];
1353
1354 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1355 MethodType caseType = args.function.resolvedHandle().type()
1356 .dropParameterTypes(0, 1) // drop collector
1357 .changeReturnType(returnType);
1358 String caseDescriptor = caseType.basicType().toMethodDescriptorString();
1359
1360 emitPushArgument(invoker, 2); // push cases
1361 mv.visitFieldInsn(Opcodes.GETFIELD, "java/lang/invoke/MethodHandleImpl$CasesHolder", "cases",
1362 "[Ljava/lang/invoke/MethodHandle;");
1363 int casesLocal = extendLocalsMap(new Class<?>[] { MethodHandle[].class });
1364 emitStoreInsn(L_TYPE, casesLocal);
1365
1366 Label endLabel = new Label();
1367 Label defaultLabel = new Label();
1368 Label[] caseLabels = new Label[numCases];
1369 for (int i = 0; i < caseLabels.length; i++) {
1370 caseLabels[i] = new Label();
1371 }
1372
1373 emitPushArgument(invoker, 0); // push switch input
1374 mv.visitTableSwitchInsn(0, numCases - 1, defaultLabel, caseLabels);
1375
1376 mv.visitLabel(defaultLabel);
1377 emitPushArgument(invoker, 1); // push default handle
1378 emitPushArguments(args, 1); // again, skip collector
1379 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", caseDescriptor, false);
1380 mv.visitJumpInsn(Opcodes.GOTO, endLabel);
1381
1382 for (int i = 0; i < numCases; i++) {
1383 mv.visitLabel(caseLabels[i]);
1384 // Load the particular case:
1385 emitLoadInsn(L_TYPE, casesLocal);
1386 emitIconstInsn(i);
1387 mv.visitInsn(Opcodes.AALOAD);
1388
1389 // invoke it:
1390 emitPushArguments(args, 1); // again, skip collector
1391 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", caseDescriptor, false);
1392
1393 mv.visitJumpInsn(Opcodes.GOTO, endLabel);
1394 }
1395
1396 mv.visitLabel(endLabel);
1397
1398 return result;
1399 }
1400
1401 /**
1402 * Emit bytecode for the loop idiom.
1403 * <p>
1404 * The pattern looks like (Cf. MethodHandleImpl.loop):
1405 * <blockquote><pre>{@code
1406 * // a0: BMH
1407 * // a1: LoopClauses (containing an array of arrays: inits, steps, preds, finis)
1408 * // a2: box, a3: unbox
1409 * // a4 (and following): arguments
1410 * loop=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L)=>{
1411 * t5:L=MethodHandle.invokeBasic(a2:L,a4:L); // box the arguments into an Object[]
1412 * t6:L=MethodHandleImpl.loop(bt:L,a1:L,t5:L); // call the loop executor (with supplied types in bt)
1413 * t7:L=MethodHandle.invokeBasic(a3:L,t6:L);t7:L} // unbox the result; return the result
1414 * }</pre></blockquote>
1415 * <p>
1416 * It is compiled into bytecode equivalent to the code seen in {@link MethodHandleImpl#loop(BasicType[],
1417 * MethodHandleImpl.LoopClauses, Object...)}, with the difference that no arrays
1418 * will be used for local state storage. Instead, the local state will be mapped to actual stack slots.
1419 * <p>
1420 * Bytecode generation applies an unrolling scheme to enable better bytecode generation regarding local state type
1421 * handling. The generated bytecode will have the following form ({@code void} types are ignored for convenience).
1422 * Assume there are {@code C} clauses in the loop.
1423 * <blockquote><pre>{@code
1424 * PREINIT: ALOAD_1
1425 * CHECKCAST LoopClauses
1426 * GETFIELD LoopClauses.clauses
1427 * ASTORE clauseDataIndex // place the clauses 2-dimensional array on the stack
1428 * INIT: (INIT_SEQ for clause 1)
1429 * ...
1430 * (INIT_SEQ for clause C)
1431 * LOOP: (LOOP_SEQ for clause 1)
1432 * ...
1433 * (LOOP_SEQ for clause C)
1434 * GOTO LOOP
1435 * DONE: ...
1436 * }</pre></blockquote>
1437 * <p>
1438 * The {@code INIT_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has
1439 * the following shape. Assume slot {@code vx} is used to hold the state for clause {@code x}.
1440 * <blockquote><pre>{@code
1441 * INIT_SEQ_x: ALOAD clauseDataIndex
1442 * ICONST_0
1443 * AALOAD // load the inits array
1444 * ICONST x
1445 * AALOAD // load the init handle for clause x
1446 * load args
1447 * INVOKEVIRTUAL MethodHandle.invokeBasic
1448 * store vx
1449 * }</pre></blockquote>
1450 * <p>
1451 * The {@code LOOP_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has
1452 * the following shape. Again, assume slot {@code vx} is used to hold the state for clause {@code x}.
1453 * <blockquote><pre>{@code
1454 * LOOP_SEQ_x: ALOAD clauseDataIndex
1455 * ICONST_1
1456 * AALOAD // load the steps array
1457 * ICONST x
1458 * AALOAD // load the step handle for clause x
1459 * load locals
1460 * load args
1461 * INVOKEVIRTUAL MethodHandle.invokeBasic
1462 * store vx
1463 * ALOAD clauseDataIndex
1464 * ICONST_2
1465 * AALOAD // load the preds array
1466 * ICONST x
1467 * AALOAD // load the pred handle for clause x
1468 * load locals
1469 * load args
1470 * INVOKEVIRTUAL MethodHandle.invokeBasic
1471 * IFNE LOOP_SEQ_x+1 // predicate returned false -> jump to next clause
1472 * ALOAD clauseDataIndex
1473 * ICONST_3
1474 * AALOAD // load the finis array
1475 * ICONST x
1476 * AALOAD // load the fini handle for clause x
1477 * load locals
1478 * load args
1479 * INVOKEVIRTUAL MethodHandle.invokeBasic
1480 * GOTO DONE // jump beyond end of clauses to return from loop
1481 * }</pre></blockquote>
1482 */
1483 private Name emitLoop(int pos) {
1484 Name args = lambdaForm.names[pos];
1485 Name invoker = lambdaForm.names[pos+1];
1486 Name result = lambdaForm.names[pos+2];
1487
1488 // extract clause and loop-local state types
1489 // find the type info in the loop invocation
1490 BasicType[] loopClauseTypes = (BasicType[]) invoker.arguments[0];
1491 Class<?>[] loopLocalStateTypes = Stream.of(loopClauseTypes).
1492 filter(bt -> bt != BasicType.V_TYPE).map(BasicType::basicTypeClass).toArray(Class<?>[]::new);
1493 Class<?>[] localTypes = new Class<?>[loopLocalStateTypes.length + 1];
1494 localTypes[0] = MethodHandleImpl.LoopClauses.class;
1495 System.arraycopy(loopLocalStateTypes, 0, localTypes, 1, loopLocalStateTypes.length);
1496
1497 final int clauseDataIndex = extendLocalsMap(localTypes);
1498 final int firstLoopStateIndex = clauseDataIndex + 1;
1499
1500 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1501 MethodType loopType = args.function.resolvedHandle().type()
1502 .dropParameterTypes(0,1)
1503 .changeReturnType(returnType);
1504 MethodType loopHandleType = loopType.insertParameterTypes(0, loopLocalStateTypes);
1505 MethodType predType = loopHandleType.changeReturnType(boolean.class);
1506 MethodType finiType = loopHandleType;
1507
1508 final int nClauses = loopClauseTypes.length;
1509
1510 // indices to invoker arguments to load method handle arrays
1511 final int inits = 1;
1512 final int steps = 2;
1513 final int preds = 3;
1514 final int finis = 4;
1515
1516 Label lLoop = new Label();
1517 Label lDone = new Label();
1518 Label lNext;
1519
1520 // PREINIT:
1521 emitPushArgument(MethodHandleImpl.LoopClauses.class, invoker.arguments[1]);
1522 mv.visitFieldInsn(Opcodes.GETFIELD, LOOP_CLAUSES, "clauses", MHARY2);
1523 emitAstoreInsn(clauseDataIndex);
1524
1525 // INIT:
1526 for (int c = 0, state = 0; c < nClauses; ++c) {
1527 MethodType cInitType = loopType.changeReturnType(loopClauseTypes[c].basicTypeClass());
1528 emitLoopHandleInvoke(invoker, inits, c, args, false, cInitType, loopLocalStateTypes, clauseDataIndex,
1529 firstLoopStateIndex);
1530 if (cInitType.returnType() != void.class) {
1531 emitStoreInsn(BasicType.basicType(cInitType.returnType()), firstLoopStateIndex + state);
1532 ++state;
1533 }
1534 }
1535
1536 // LOOP:
1537 mv.visitLabel(lLoop);
1538
1539 for (int c = 0, state = 0; c < nClauses; ++c) {
1540 lNext = new Label();
1541
1542 MethodType stepType = loopHandleType.changeReturnType(loopClauseTypes[c].basicTypeClass());
1543 boolean isVoid = stepType.returnType() == void.class;
1544
1545 // invoke loop step
1546 emitLoopHandleInvoke(invoker, steps, c, args, true, stepType, loopLocalStateTypes, clauseDataIndex,
1547 firstLoopStateIndex);
1548 if (!isVoid) {
1549 emitStoreInsn(BasicType.basicType(stepType.returnType()), firstLoopStateIndex + state);
1550 ++state;
1551 }
1552
1553 // invoke loop predicate
1554 emitLoopHandleInvoke(invoker, preds, c, args, true, predType, loopLocalStateTypes, clauseDataIndex,
1555 firstLoopStateIndex);
1556 mv.visitJumpInsn(Opcodes.IFNE, lNext);
1557
1558 // invoke fini
1559 emitLoopHandleInvoke(invoker, finis, c, args, true, finiType, loopLocalStateTypes, clauseDataIndex,
1560 firstLoopStateIndex);
1561 mv.visitJumpInsn(Opcodes.GOTO, lDone);
1562
1563 // this is the beginning of the next loop clause
1564 mv.visitLabel(lNext);
1565 }
1566
1567 mv.visitJumpInsn(Opcodes.GOTO, lLoop);
1568
1569 // DONE:
1570 mv.visitLabel(lDone);
1571
1572 return result;
1573 }
1574
1575 private int extendLocalsMap(Class<?>[] types) {
1576 int firstSlot = localsMap.length - 1;
1577 localsMap = Arrays.copyOf(localsMap, localsMap.length + types.length);
1578 localClasses = Arrays.copyOf(localClasses, localClasses.length + types.length);
1579 System.arraycopy(types, 0, localClasses, firstSlot, types.length);
1580 int index = localsMap[firstSlot - 1] + 1;
1581 int lastSlots = 0;
1582 for (int i = 0; i < types.length; ++i) {
1583 localsMap[firstSlot + i] = index;
1584 lastSlots = BasicType.basicType(localClasses[firstSlot + i]).basicTypeSlots();
1585 index += lastSlots;
1586 }
1587 localsMap[localsMap.length - 1] = index - lastSlots;
1588 return firstSlot;
1589 }
1590
1591 private void emitLoopHandleInvoke(Name holder, int handles, int clause, Name args, boolean pushLocalState,
1592 MethodType type, Class<?>[] loopLocalStateTypes, int clauseDataSlot,
1593 int firstLoopStateSlot) {
1594 // load handle for clause
1595 emitPushClauseArray(clauseDataSlot, handles);
1596 emitIconstInsn(clause);
1597 mv.visitInsn(Opcodes.AALOAD);
1598 // load loop state (preceding the other arguments)
1599 if (pushLocalState) {
1600 for (int s = 0; s < loopLocalStateTypes.length; ++s) {
1601 emitLoadInsn(BasicType.basicType(loopLocalStateTypes[s]), firstLoopStateSlot + s);
1602 }
1603 }
1604 // load loop args (skip 0: method handle)
1605 emitPushArguments(args, 1);
1606 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.toMethodDescriptorString(), false);
1607 }
1608
1609 private void emitPushClauseArray(int clauseDataSlot, int which) {
1610 emitAloadInsn(clauseDataSlot);
1611 emitIconstInsn(which - 1);
1612 mv.visitInsn(Opcodes.AALOAD);
1613 }
1614
1615 private void emitZero(BasicType type) {
1616 mv.visitInsn(switch (type) {
1617 case I_TYPE -> Opcodes.ICONST_0;
1618 case J_TYPE -> Opcodes.LCONST_0;
1619 case F_TYPE -> Opcodes.FCONST_0;
1620 case D_TYPE -> Opcodes.DCONST_0;
1621 case L_TYPE -> Opcodes.ACONST_NULL;
1622 default -> throw new InternalError("unknown type: " + type);
1623 });
1624 }
1625
1626 private void emitPushArguments(Name args, int start) {
1627 MethodType type = args.function.methodType();
1628 for (int i = start; i < args.arguments.length; i++) {
1629 emitPushArgument(type.parameterType(i), args.arguments[i]);
1630 }
1631 }
1632
1633 private void emitPushArgument(Name name, int paramIndex) {
1634 Object arg = name.arguments[paramIndex];
1635 Class<?> ptype = name.function.methodType().parameterType(paramIndex);
1636 emitPushArgument(ptype, arg);
1637 }
1638
1639 private void emitPushArgument(Class<?> ptype, Object arg) {
1640 BasicType bptype = basicType(ptype);
1641 if (arg instanceof Name n) {
1642 emitLoadInsn(n.type, n.index());
1643 emitImplicitConversion(n.type, ptype, n);
1644 } else if (arg == null && bptype == L_TYPE) {
1645 mv.visitInsn(Opcodes.ACONST_NULL);
1646 } else if (arg instanceof String && bptype == L_TYPE) {
1647 mv.visitLdcInsn(arg);
1648 } else {
1649 if (Wrapper.isWrapperType(arg.getClass()) && bptype != L_TYPE) {
1650 emitConst(arg);
1651 } else {
1652 mv.visitFieldInsn(Opcodes.GETSTATIC, className, classData(arg), "Ljava/lang/Object;");
1653 emitImplicitConversion(L_TYPE, ptype, arg);
1654 }
1655 }
1656 }
1657
1658 /**
1659 * Store the name to its local, if necessary.
1660 */
1661 private void emitStoreResult(Name name) {
1662 if (name != null && name.type != V_TYPE) {
1663 // non-void: actually assign
1664 emitStoreInsn(name.type, name.index());
1665 }
1666 }
1667
1668 /**
1669 * Emits a return statement from a LF invoker. If required, the result type is cast to the correct return type.
1670 */
1671 private void emitReturn(Name onStack) {
1672 // return statement
1673 Class<?> rclass = invokerType.returnType();
1674 BasicType rtype = lambdaForm.returnType();
1675 assert(rtype == basicType(rclass)); // must agree
1676 if (rtype == V_TYPE) {
1677 // void
1678 mv.visitInsn(Opcodes.RETURN);
1679 // it doesn't matter what rclass is; the JVM will discard any value
1680 } else {
1681 LambdaForm.Name rn = lambdaForm.names[lambdaForm.result];
1682
1683 // put return value on the stack if it is not already there
1684 if (rn != onStack) {
1685 emitLoadInsn(rtype, lambdaForm.result);
1686 }
1687
1688 emitImplicitConversion(rtype, rclass, rn);
1689
1690 // generate actual return statement
1691 emitReturnInsn(rtype);
1692 }
1693 }
1694
1695 /**
1696 * Emit a type conversion bytecode casting from "from" to "to".
1697 */
1698 private void emitPrimCast(Wrapper from, Wrapper to) {
1699 // Here's how.
1700 // - indicates forbidden
1701 // <-> indicates implicit
1702 // to ----> boolean byte short char int long float double
1703 // from boolean <-> - - - - - - -
1704 // byte - <-> i2s i2c <-> i2l i2f i2d
1705 // short - i2b <-> i2c <-> i2l i2f i2d
1706 // char - i2b i2s <-> <-> i2l i2f i2d
1707 // int - i2b i2s i2c <-> i2l i2f i2d
1708 // long - l2i,i2b l2i,i2s l2i,i2c l2i <-> l2f l2d
1709 // float - f2i,i2b f2i,i2s f2i,i2c f2i f2l <-> f2d
1710 // double - d2i,i2b d2i,i2s d2i,i2c d2i d2l d2f <->
1711 if (from == to) {
1712 // no cast required, should be dead code anyway
1713 return;
1714 }
1715 if (from.isSubwordOrInt()) {
1716 // cast from {byte,short,char,int} to anything
1717 emitI2X(to);
1718 } else {
1719 // cast from {long,float,double} to anything
1720 if (to.isSubwordOrInt()) {
1721 // cast to {byte,short,char,int}
1722 emitX2I(from);
1723 if (to.bitWidth() < 32) {
1724 // targets other than int require another conversion
1725 emitI2X(to);
1726 }
1727 } else {
1728 // cast to {long,float,double} - this is verbose
1729 boolean error = false;
1730 switch (from) {
1731 case LONG -> {
1732 switch (to) {
1733 case FLOAT -> mv.visitInsn(Opcodes.L2F);
1734 case DOUBLE -> mv.visitInsn(Opcodes.L2D);
1735 default -> error = true;
1736 }
1737 }
1738 case FLOAT -> {
1739 switch (to) {
1740 case LONG -> mv.visitInsn(Opcodes.F2L);
1741 case DOUBLE -> mv.visitInsn(Opcodes.F2D);
1742 default -> error = true;
1743 }
1744 }
1745 case DOUBLE -> {
1746 switch (to) {
1747 case LONG -> mv.visitInsn(Opcodes.D2L);
1748 case FLOAT -> mv.visitInsn(Opcodes.D2F);
1749 default -> error = true;
1750 }
1751 }
1752 default -> error = true;
1753 }
1754 if (error) {
1755 throw new IllegalStateException("unhandled prim cast: " + from + "2" + to);
1756 }
1757 }
1758 }
1759 }
1760
1761 private void emitI2X(Wrapper type) {
1762 switch (type) {
1763 case BYTE: mv.visitInsn(Opcodes.I2B); break;
1764 case SHORT: mv.visitInsn(Opcodes.I2S); break;
1765 case CHAR: mv.visitInsn(Opcodes.I2C); break;
1766 case INT: /* naught */ break;
1767 case LONG: mv.visitInsn(Opcodes.I2L); break;
1768 case FLOAT: mv.visitInsn(Opcodes.I2F); break;
1769 case DOUBLE: mv.visitInsn(Opcodes.I2D); break;
1770 case BOOLEAN:
1771 // For compatibility with ValueConversions and explicitCastArguments:
1772 mv.visitInsn(Opcodes.ICONST_1);
1773 mv.visitInsn(Opcodes.IAND);
1774 break;
1775 default: throw new InternalError("unknown type: " + type);
1776 }
1777 }
1778
1779 private void emitX2I(Wrapper type) {
1780 switch (type) {
1781 case LONG -> mv.visitInsn(Opcodes.L2I);
1782 case FLOAT -> mv.visitInsn(Opcodes.F2I);
1783 case DOUBLE -> mv.visitInsn(Opcodes.D2I);
1784 default -> throw new InternalError("unknown type: " + type);
1785 }
1786 }
1787
1788 /**
1789 * Generate bytecode for a LambdaForm.vmentry which calls interpretWithArguments.
1790 */
1791 static MemberName generateLambdaFormInterpreterEntryPoint(MethodType mt) {
1792 assert(isValidSignature(basicTypeSignature(mt)));
1793 String name = "interpret_"+basicTypeChar(mt.returnType());
1794 MethodType type = mt; // includes leading argument
1795 type = type.changeParameterType(0, MethodHandle.class);
1796 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("LFI", name, type);
1797 return g.loadMethod(g.generateLambdaFormInterpreterEntryPointBytes());
1798 }
1799
1800 private byte[] generateLambdaFormInterpreterEntryPointBytes() {
1801 classFilePrologue();
1802 methodPrologue();
1803
1804 // Suppress this method in backtraces displayed to the user.
1805 mv.visitAnnotation(HIDDEN_SIG, true);
1806
1807 // Don't inline the interpreter entry.
1808 mv.visitAnnotation(DONTINLINE_SIG, true);
1809
1810 // create parameter array
1811 emitIconstInsn(invokerType.parameterCount());
1812 mv.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object");
1813
1814 // fill parameter array
1815 for (int i = 0; i < invokerType.parameterCount(); i++) {
1816 Class<?> ptype = invokerType.parameterType(i);
1817 mv.visitInsn(Opcodes.DUP);
1818 emitIconstInsn(i);
1819 emitLoadInsn(basicType(ptype), i);
1820 // box if primitive type
1821 if (ptype.isPrimitive()) {
1822 emitBoxing(Wrapper.forPrimitiveType(ptype));
1823 }
1824 mv.visitInsn(Opcodes.AASTORE);
1825 }
1826 // invoke
1827 emitAloadInsn(0);
1828 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", "Ljava/lang/invoke/LambdaForm;");
1829 mv.visitInsn(Opcodes.SWAP); // swap form and array; avoid local variable
1830 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, LF, "interpretWithArguments", "([Ljava/lang/Object;)Ljava/lang/Object;", false);
1831
1832 // maybe unbox
1833 Class<?> rtype = invokerType.returnType();
1834 if (rtype.isPrimitive() && rtype != void.class) {
1835 emitUnboxing(Wrapper.forPrimitiveType(rtype));
1836 }
1837
1838 // return statement
1839 emitReturnInsn(basicType(rtype));
1840
1841 methodEpilogue();
1842 clinit(cw, className, classData);
1843 bogusMethod(invokerType);
1844
1845 return cw.toByteArray();
1846 }
1847
1848 /**
1849 * Generate bytecode for a NamedFunction invoker.
1850 */
1851 static MemberName generateNamedFunctionInvoker(MethodTypeForm typeForm) {
1852 MethodType invokerType = NamedFunction.INVOKER_METHOD_TYPE;
1853 String invokerName = "invoke_" + shortenSignature(basicTypeSignature(typeForm.erasedType()));
1854 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("NFI", invokerName, invokerType);
1855 return g.loadMethod(g.generateNamedFunctionInvokerImpl(typeForm));
1856 }
1857
1858 private byte[] generateNamedFunctionInvokerImpl(MethodTypeForm typeForm) {
1859 MethodType dstType = typeForm.erasedType();
1860 classFilePrologue();
1861 methodPrologue();
1862
1863 // Suppress this method in backtraces displayed to the user.
1864 mv.visitAnnotation(HIDDEN_SIG, true);
1865
1866 // Force inlining of this invoker method.
1867 mv.visitAnnotation(FORCEINLINE_SIG, true);
1868
1869 // Load receiver
1870 emitAloadInsn(0);
1871
1872 // Load arguments from array
1873 for (int i = 0; i < dstType.parameterCount(); i++) {
1874 emitAloadInsn(1);
1875 emitIconstInsn(i);
1876 mv.visitInsn(Opcodes.AALOAD);
1877
1878 // Maybe unbox
1879 Class<?> dptype = dstType.parameterType(i);
1880 if (dptype.isPrimitive()) {
1881 Wrapper dstWrapper = Wrapper.forBasicType(dptype);
1882 Wrapper srcWrapper = dstWrapper.isSubwordOrInt() ? Wrapper.INT : dstWrapper; // narrow subword from int
1883 emitUnboxing(srcWrapper);
1884 emitPrimCast(srcWrapper, dstWrapper);
1885 }
1886 }
1887
1888 // Invoke
1889 String targetDesc = dstType.basicType().toMethodDescriptorString();
1890 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", targetDesc, false);
1891
1892 // Box primitive types
1893 Class<?> rtype = dstType.returnType();
1894 if (rtype != void.class && rtype.isPrimitive()) {
1895 Wrapper srcWrapper = Wrapper.forBasicType(rtype);
1896 Wrapper dstWrapper = srcWrapper.isSubwordOrInt() ? Wrapper.INT : srcWrapper; // widen subword to int
1897 // boolean casts not allowed
1898 emitPrimCast(srcWrapper, dstWrapper);
1899 emitBoxing(dstWrapper);
1900 }
1901
1902 // If the return type is void we return a null reference.
1903 if (rtype == void.class) {
1904 mv.visitInsn(Opcodes.ACONST_NULL);
1905 }
1906 emitReturnInsn(L_TYPE); // NOTE: NamedFunction invokers always return a reference value.
1907
1908 methodEpilogue();
1909 clinit(cw, className, classData);
1910 bogusMethod(dstType);
1911
1912 return cw.toByteArray();
1913 }
1914
1915 /**
1916 * Emit a bogus method that just loads some string constants. This is to get the constants into the constant pool
1917 * for debugging purposes.
1918 */
1919 private void bogusMethod(Object os) {
1920 if (dumper().isEnabled()) {
1921 mv = cw.visitMethod(Opcodes.ACC_STATIC, "dummy", "()V", null, null);
1922 mv.visitLdcInsn(os.toString());
1923 mv.visitInsn(Opcodes.POP);
1924 mv.visitInsn(Opcodes.RETURN);
1925 mv.visitMaxs(0, 0);
1926 mv.visitEnd();
1927 }
1928 }
1929 }