1 /*
2 * Copyright (c) 2012, 2022, 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 import sun.reflect.misc.ReflectUtil;
38
39 import java.io.File;
40 import java.io.FileOutputStream;
41 import java.io.IOException;
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.stream.Stream;
49
50 import static java.lang.invoke.LambdaForm.BasicType;
51 import static java.lang.invoke.LambdaForm.BasicType.*;
52 import static java.lang.invoke.LambdaForm.*;
53 import static java.lang.invoke.MethodHandleNatives.Constants.*;
54 import static java.lang.invoke.MethodHandleStatics.*;
55 import static java.lang.invoke.MethodHandles.Lookup.*;
56
57 /**
58 * Code generation backend for LambdaForm.
59 * <p>
60 * @author John Rose, JSR 292 EG
61 */
62 class InvokerBytecodeGenerator {
63 /** Define class names for convenience. */
64 private static final String MH = "java/lang/invoke/MethodHandle";
65 private static final String MHI = "java/lang/invoke/MethodHandleImpl";
66 private static final String LF = "java/lang/invoke/LambdaForm";
67 private static final String LFN = "java/lang/invoke/LambdaForm$Name";
68 private static final String CLS = "java/lang/Class";
69 private static final String OBJ = "java/lang/Object";
70 private static final String OBJARY = "[Ljava/lang/Object;";
71
72 private static final String LOOP_CLAUSES = MHI + "$LoopClauses";
73 private static final String MHARY2 = "[[L" + MH + ";";
74 private static final String MH_SIG = "L" + MH + ";";
75
76
77 private static final String LF_SIG = "L" + LF + ";";
78 private static final String LFN_SIG = "L" + LFN + ";";
79 private static final String LL_SIG = "(L" + OBJ + ";)L" + OBJ + ";";
80 private static final String LLV_SIG = "(L" + OBJ + ";L" + OBJ + ";)V";
81 private static final String CLASS_PREFIX = LF + "$";
82 private static final String SOURCE_PREFIX = "LambdaForm$";
83
84 /** Name of its super class*/
85 static final String INVOKER_SUPER_NAME = OBJ;
86
87 /** Name of new class */
88 private final String name;
89 private final String className;
90
91 private final LambdaForm lambdaForm;
92 private final String invokerName;
93 private final MethodType invokerType;
94
95 /** Info about local variables in compiled lambda form */
96 private int[] localsMap; // index
97 private Class<?>[] localClasses; // type
98
99 /** ASM bytecode generation. */
100 private ClassWriter cw;
101 private MethodVisitor mv;
102 private final List<ClassData> classData = new ArrayList<>();
103
104 /** Single element internal class name lookup cache. */
105 private Class<?> lastClass;
106 private String lastInternalName;
107
108 private static final MemberName.Factory MEMBERNAME_FACTORY = MemberName.getFactory();
109 private static final Class<?> HOST_CLASS = LambdaForm.class;
110 private static final MethodHandles.Lookup LOOKUP = lookup();
111
112 private static MethodHandles.Lookup lookup() {
113 try {
114 return MethodHandles.privateLookupIn(HOST_CLASS, IMPL_LOOKUP);
115 } catch (IllegalAccessException e) {
116 throw newInternalError(e);
117 }
118 }
119
120 /** Main constructor; other constructors delegate to this one. */
121 private InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize,
122 String name, String invokerName, MethodType invokerType) {
123 int p = invokerName.indexOf('.');
124 if (p > -1) {
125 name = invokerName.substring(0, p);
126 invokerName = invokerName.substring(p + 1);
127 }
128 if (DUMP_CLASS_FILES) {
129 name = makeDumpableClassName(name);
130 }
131 this.name = name;
132 this.className = CLASS_PREFIX + name;
133 this.lambdaForm = lambdaForm;
134 this.invokerName = invokerName;
135 this.invokerType = invokerType;
136 this.localsMap = new int[localsMapSize+1]; // last entry of localsMap is count of allocated local slots
137 this.localClasses = new Class<?>[localsMapSize+1];
138 }
139
140 /** For generating LambdaForm interpreter entry points. */
141 private InvokerBytecodeGenerator(String name, String invokerName, MethodType invokerType) {
142 this(null, invokerType.parameterCount(),
143 name, invokerName, invokerType);
144 MethodType mt = invokerType.erase();
145 // Create an array to map name indexes to locals indexes.
146 localsMap[0] = 0; // localsMap has at least one element
147 for (int i = 1, index = 0; i < localsMap.length; i++) {
148 Wrapper w = Wrapper.forBasicType(mt.parameterType(i - 1));
149 index += w.stackSlots();
150 localsMap[i] = index;
151 }
152 }
153
154 /** For generating customized code for a single LambdaForm. */
155 private InvokerBytecodeGenerator(String name, LambdaForm form, MethodType invokerType) {
156 this(name, form.lambdaName(), form, invokerType);
157 }
158
159 /** For generating customized code for a single LambdaForm. */
160 InvokerBytecodeGenerator(String name, String invokerName,
161 LambdaForm form, MethodType invokerType) {
162 this(form, form.names.length,
163 name, invokerName, invokerType);
164 // Create an array to map name indexes to locals indexes.
165 Name[] names = form.names;
166 for (int i = 0, index = 0; i < localsMap.length; i++) {
167 localsMap[i] = index;
168 if (i < names.length) {
169 BasicType type = names[i].type();
170 index += type.basicTypeSlots();
171 }
172 }
173 }
174
175 /** instance counters for dumped classes */
176 private static final HashMap<String,Integer> DUMP_CLASS_FILES_COUNTERS;
177 /** debugging flag for saving generated class files */
178 private static final File DUMP_CLASS_FILES_DIR;
179
180 static {
181 if (DUMP_CLASS_FILES) {
182 DUMP_CLASS_FILES_COUNTERS = new HashMap<>();
183 try {
184 File dumpDir = new File("DUMP_CLASS_FILES");
185 if (!dumpDir.exists()) {
186 dumpDir.mkdirs();
187 }
188 DUMP_CLASS_FILES_DIR = dumpDir;
189 System.out.println("Dumping class files to "+DUMP_CLASS_FILES_DIR+"/...");
190 } catch (Exception e) {
191 throw newInternalError(e);
192 }
193 } else {
194 DUMP_CLASS_FILES_COUNTERS = null;
195 DUMP_CLASS_FILES_DIR = null;
196 }
197 }
198
199 private void maybeDump(final byte[] classFile) {
200 if (DUMP_CLASS_FILES) {
201 maybeDump(className, classFile);
202 }
203 }
204
205 // Also used from BoundMethodHandle
206 @SuppressWarnings("removal")
207 static void maybeDump(final String className, final byte[] classFile) {
208 if (DUMP_CLASS_FILES) {
209 java.security.AccessController.doPrivileged(
210 new java.security.PrivilegedAction<>() {
211 public Void run() {
212 try {
213 String dumpName = className.replace('.','/');
214 File dumpFile = new File(DUMP_CLASS_FILES_DIR, dumpName+".class");
215 System.out.println("dump: " + dumpFile);
216 dumpFile.getParentFile().mkdirs();
217 FileOutputStream file = new FileOutputStream(dumpFile);
218 file.write(classFile);
219 file.close();
220 return null;
221 } catch (IOException ex) {
222 throw newInternalError(ex);
223 }
224 }
225 });
226 }
227 }
228
229 private static String makeDumpableClassName(String className) {
230 Integer ctr;
231 synchronized (DUMP_CLASS_FILES_COUNTERS) {
232 ctr = DUMP_CLASS_FILES_COUNTERS.get(className);
233 if (ctr == null) ctr = 0;
234 DUMP_CLASS_FILES_COUNTERS.put(className, ctr+1);
235 }
236 String sfx = ctr.toString();
237 while (sfx.length() < 3)
238 sfx = "0" + sfx;
239 className += sfx;
240 return className;
241 }
242
243 static class ClassData {
244 final String name;
245 final String desc;
246 final Object value;
247
248 ClassData(String name, String desc, Object value) {
249 this.name = name;
250 this.desc = desc;
251 this.value = value;
252 }
253
254 public String name() { return name; }
255 public String toString() {
256 return name + ",value="+value;
257 }
258 }
259
260 String classData(Object arg) {
261 String desc;
262 if (arg instanceof Class) {
263 desc = "Ljava/lang/Class;";
264 } else if (arg instanceof MethodHandle) {
265 desc = MH_SIG;
266 } else if (arg instanceof LambdaForm) {
267 desc = LF_SIG;
268 } else {
269 desc = "Ljava/lang/Object;";
270 }
271
272 // unique static variable name
273 String name;
274 if (DUMP_CLASS_FILES) {
275 Class<?> c = arg.getClass();
276 while (c.isArray()) {
277 c = c.getComponentType();
278 }
279 name = "_DATA_" + c.getSimpleName() + "_" + classData.size();
280 } else {
281 name = "_D_" + classData.size();
282 }
283 ClassData cd = new ClassData(name, desc, arg);
284 classData.add(cd);
285 return name;
286 }
287
288 private static String debugString(Object arg) {
289 if (arg instanceof MethodHandle mh) {
290 MemberName member = mh.internalMemberName();
291 if (member != null)
292 return member.toString();
293 return mh.debugString();
294 }
295 return arg.toString();
296 }
297
298 /**
299 * Extract the MemberName of a newly-defined method.
300 */
301 private MemberName loadMethod(byte[] classFile) {
302 Class<?> invokerClass = LOOKUP.makeHiddenClassDefiner(className, classFile, Set.of())
303 .defineClass(true, classDataValues());
304 return resolveInvokerMember(invokerClass, invokerName, invokerType);
305 }
306
307 private static MemberName resolveInvokerMember(Class<?> invokerClass, String name, MethodType type) {
308 MemberName member = new MemberName(invokerClass, name, type, REF_invokeStatic);
309 try {
310 member = MEMBERNAME_FACTORY.resolveOrFail(REF_invokeStatic, member,
311 HOST_CLASS, LM_TRUSTED,
312 ReflectiveOperationException.class);
313 } catch (ReflectiveOperationException e) {
314 throw newInternalError(e);
315 }
316 return member;
317 }
318
319 /**
320 * Set up class file generation.
321 */
322 private ClassWriter classFilePrologue() {
323 final int NOT_ACC_PUBLIC = 0; // not ACC_PUBLIC
324 ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
325 setClassWriter(cw);
326 cw.visit(CLASSFILE_VERSION, NOT_ACC_PUBLIC + Opcodes.ACC_FINAL + Opcodes.ACC_SUPER,
327 className, null, INVOKER_SUPER_NAME, null);
328 cw.visitSource(SOURCE_PREFIX + name, null);
329 return cw;
330 }
331
332 private void methodPrologue() {
333 String invokerDesc = invokerType.toMethodDescriptorString();
334 mv = cw.visitMethod(Opcodes.ACC_STATIC, invokerName, invokerDesc, null, null);
335 }
336
337 /**
338 * Tear down class file generation.
339 */
340 private void methodEpilogue() {
341 mv.visitMaxs(0, 0);
342 mv.visitEnd();
343 }
344
345 /**
346 * Returns the class data object that will be passed to `Lookup.defineHiddenClassWithClassData`.
347 * The classData is loaded in the <clinit> method of the generated class.
348 * If the class data contains only one single object, this method returns that single object.
349 * If the class data contains more than one objects, this method returns a List.
350 *
351 * This method returns null if no class data.
352 */
353 private Object classDataValues() {
354 final List<ClassData> cd = classData;
355 return switch (cd.size()) {
356 case 0 -> null; // special case (classData is not used by <clinit>)
357 case 1 -> cd.get(0).value; // special case (single object)
358 case 2 -> List.of(cd.get(0).value, cd.get(1).value);
359 case 3 -> List.of(cd.get(0).value, cd.get(1).value, cd.get(2).value);
360 case 4 -> List.of(cd.get(0).value, cd.get(1).value, cd.get(2).value, cd.get(3).value);
361 default -> {
362 Object[] data = new Object[classData.size()];
363 for (int i = 0; i < classData.size(); i++) {
364 data[i] = classData.get(i).value;
365 }
366 yield List.of(data);
367 }
368 };
369 }
370
371 /*
372 * <clinit> to initialize the static final fields with the live class data
373 * LambdaForms can't use condy due to bootstrapping issue.
374 */
375 static void clinit(ClassWriter cw, String className, List<ClassData> classData) {
376 if (classData.isEmpty())
377 return;
378
379 for (ClassData p : classData) {
380 // add the static field
381 FieldVisitor fv = cw.visitField(Opcodes.ACC_STATIC|Opcodes.ACC_FINAL, p.name, p.desc, null, null);
382 fv.visitEnd();
383 }
384
385 MethodVisitor mv = cw.visitMethod(Opcodes.ACC_STATIC, "<clinit>", "()V", null, null);
386 mv.visitCode();
387 mv.visitLdcInsn(Type.getType("L" + className + ";"));
388 mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/invoke/MethodHandles",
389 "classData", "(Ljava/lang/Class;)Ljava/lang/Object;", false);
390 if (classData.size() == 1) {
391 ClassData p = classData.get(0);
392 mv.visitTypeInsn(Opcodes.CHECKCAST, p.desc.substring(1, p.desc.length()-1));
393 mv.visitFieldInsn(Opcodes.PUTSTATIC, className, p.name, p.desc);
394 } else {
395 mv.visitTypeInsn(Opcodes.CHECKCAST, "java/util/List");
396 mv.visitVarInsn(Opcodes.ASTORE, 0);
397 int index = 0;
398 for (ClassData p : classData) {
399 // initialize the static field
400 mv.visitVarInsn(Opcodes.ALOAD, 0);
401 emitIconstInsn(mv, index++);
402 mv.visitMethodInsn(Opcodes.INVOKEINTERFACE, "java/util/List",
403 "get", "(I)Ljava/lang/Object;", true);
404 mv.visitTypeInsn(Opcodes.CHECKCAST, p.desc.substring(1, p.desc.length()-1));
405 mv.visitFieldInsn(Opcodes.PUTSTATIC, className, p.name, p.desc);
406 }
407 }
408 mv.visitInsn(Opcodes.RETURN);
409 mv.visitMaxs(2, 1);
410 mv.visitEnd();
411 }
412
413 /*
414 * Low-level emit helpers.
415 */
416 private void emitConst(Object con) {
417 if (con == null) {
418 mv.visitInsn(Opcodes.ACONST_NULL);
419 return;
420 }
421 if (con instanceof Integer) {
422 emitIconstInsn((int) con);
423 return;
424 }
425 if (con instanceof Byte) {
426 emitIconstInsn((byte)con);
427 return;
428 }
429 if (con instanceof Short) {
430 emitIconstInsn((short)con);
431 return;
432 }
433 if (con instanceof Character) {
434 emitIconstInsn((char)con);
435 return;
436 }
437 if (con instanceof Long) {
438 long x = (long) con;
439 short sx = (short)x;
440 if (x == sx) {
441 if (sx >= 0 && sx <= 1) {
442 mv.visitInsn(Opcodes.LCONST_0 + (int) sx);
443 } else {
444 emitIconstInsn((int) x);
445 mv.visitInsn(Opcodes.I2L);
446 }
447 return;
448 }
449 }
450 if (con instanceof Float) {
451 float x = (float) con;
452 short sx = (short)x;
453 if (x == sx) {
454 if (sx >= 0 && sx <= 2) {
455 mv.visitInsn(Opcodes.FCONST_0 + (int) sx);
456 } else {
457 emitIconstInsn((int) x);
458 mv.visitInsn(Opcodes.I2F);
459 }
460 return;
461 }
462 }
463 if (con instanceof Double) {
464 double x = (double) con;
465 short sx = (short)x;
466 if (x == sx) {
467 if (sx >= 0 && sx <= 1) {
468 mv.visitInsn(Opcodes.DCONST_0 + (int) sx);
469 } else {
470 emitIconstInsn((int) x);
471 mv.visitInsn(Opcodes.I2D);
472 }
473 return;
474 }
475 }
476 if (con instanceof Boolean) {
477 emitIconstInsn((boolean) con ? 1 : 0);
478 return;
479 }
480 // fall through:
481 mv.visitLdcInsn(con);
482 }
483
484 private void emitIconstInsn(final int cst) {
485 emitIconstInsn(mv, cst);
486 }
487
488 private static void emitIconstInsn(MethodVisitor mv, int cst) {
489 if (cst >= -1 && cst <= 5) {
490 mv.visitInsn(Opcodes.ICONST_0 + cst);
491 } else if (cst >= Byte.MIN_VALUE && cst <= Byte.MAX_VALUE) {
492 mv.visitIntInsn(Opcodes.BIPUSH, cst);
493 } else if (cst >= Short.MIN_VALUE && cst <= Short.MAX_VALUE) {
494 mv.visitIntInsn(Opcodes.SIPUSH, cst);
495 } else {
496 mv.visitLdcInsn(cst);
497 }
498 }
499
500 /*
501 * NOTE: These load/store methods use the localsMap to find the correct index!
502 */
503 private void emitLoadInsn(BasicType type, int index) {
504 int opcode = loadInsnOpcode(type);
505 mv.visitVarInsn(opcode, localsMap[index]);
506 }
507
508 private int loadInsnOpcode(BasicType type) throws InternalError {
509 return switch (type) {
510 case I_TYPE -> Opcodes.ILOAD;
511 case J_TYPE -> Opcodes.LLOAD;
512 case F_TYPE -> Opcodes.FLOAD;
513 case D_TYPE -> Opcodes.DLOAD;
514 case L_TYPE -> Opcodes.ALOAD;
515 default -> throw new InternalError("unknown type: " + type);
516 };
517 }
518 private void emitAloadInsn(int index) {
519 emitLoadInsn(L_TYPE, index);
520 }
521
522 private void emitStoreInsn(BasicType type, int index) {
523 int opcode = storeInsnOpcode(type);
524 mv.visitVarInsn(opcode, localsMap[index]);
525 }
526
527 private int storeInsnOpcode(BasicType type) throws InternalError {
528 return switch (type) {
529 case I_TYPE -> Opcodes.ISTORE;
530 case J_TYPE -> Opcodes.LSTORE;
531 case F_TYPE -> Opcodes.FSTORE;
532 case D_TYPE -> Opcodes.DSTORE;
533 case L_TYPE -> Opcodes.ASTORE;
534 default -> throw new InternalError("unknown type: " + type);
535 };
536 }
537 private void emitAstoreInsn(int index) {
538 emitStoreInsn(L_TYPE, index);
539 }
540
541 private byte arrayTypeCode(Wrapper elementType) {
542 return (byte) switch (elementType) {
543 case BOOLEAN -> Opcodes.T_BOOLEAN;
544 case BYTE -> Opcodes.T_BYTE;
545 case CHAR -> Opcodes.T_CHAR;
546 case SHORT -> Opcodes.T_SHORT;
547 case INT -> Opcodes.T_INT;
548 case LONG -> Opcodes.T_LONG;
549 case FLOAT -> Opcodes.T_FLOAT;
550 case DOUBLE -> Opcodes.T_DOUBLE;
551 case OBJECT -> 0; // in place of Opcodes.T_OBJECT
552 default -> throw new InternalError();
553 };
554 }
555
556 private int arrayInsnOpcode(byte tcode, int aaop) throws InternalError {
557 assert(aaop == Opcodes.AASTORE || aaop == Opcodes.AALOAD);
558 int xas = switch (tcode) {
559 case Opcodes.T_BOOLEAN -> Opcodes.BASTORE;
560 case Opcodes.T_BYTE -> Opcodes.BASTORE;
561 case Opcodes.T_CHAR -> Opcodes.CASTORE;
562 case Opcodes.T_SHORT -> Opcodes.SASTORE;
563 case Opcodes.T_INT -> Opcodes.IASTORE;
564 case Opcodes.T_LONG -> Opcodes.LASTORE;
565 case Opcodes.T_FLOAT -> Opcodes.FASTORE;
566 case Opcodes.T_DOUBLE -> Opcodes.DASTORE;
567 case 0 -> Opcodes.AASTORE;
568 default -> throw new InternalError();
569 };
570 return xas - Opcodes.AASTORE + aaop;
571 }
572
573 /**
574 * Emit a boxing call.
575 *
576 * @param wrapper primitive type class to box.
577 */
578 private void emitBoxing(Wrapper wrapper) {
579 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
580 String name = "valueOf";
581 String desc = "(" + wrapper.basicTypeChar() + ")L" + owner + ";";
582 mv.visitMethodInsn(Opcodes.INVOKESTATIC, owner, name, desc, false);
583 }
584
585 /**
586 * Emit an unboxing call (plus preceding checkcast).
587 *
588 * @param wrapper wrapper type class to unbox.
589 */
590 private void emitUnboxing(Wrapper wrapper) {
591 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
592 String name = wrapper.primitiveSimpleName() + "Value";
593 String desc = "()" + wrapper.basicTypeChar();
594 emitReferenceCast(wrapper.wrapperType(), null);
595 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, owner, name, desc, false);
596 }
597
598 /**
599 * Emit an implicit conversion for an argument which must be of the given pclass.
600 * This is usually a no-op, except when pclass is a subword type or a reference other than Object or an interface.
601 *
602 * @param ptype type of value present on stack
603 * @param pclass type of value required on stack
604 * @param arg compile-time representation of value on stack (Node, constant) or null if none
605 */
606 private void emitImplicitConversion(BasicType ptype, Class<?> pclass, Object arg) {
607 assert(basicType(pclass) == ptype); // boxing/unboxing handled by caller
608 if (pclass == ptype.basicTypeClass() && ptype != L_TYPE)
609 return; // nothing to do
610 switch (ptype) {
611 case L_TYPE:
612 if (VerifyType.isNullConversion(Object.class, pclass, false)) {
613 if (PROFILE_LEVEL > 0)
614 emitReferenceCast(Object.class, arg);
615 return;
616 }
617 emitReferenceCast(pclass, arg);
618 return;
619 case I_TYPE:
620 if (!VerifyType.isNullConversion(int.class, pclass, false))
621 emitPrimCast(ptype.basicTypeWrapper(), Wrapper.forPrimitiveType(pclass));
622 return;
623 }
624 throw newInternalError("bad implicit conversion: tc="+ptype+": "+pclass);
625 }
626
627 /** Update localClasses type map. Return true if the information is already present. */
628 private boolean assertStaticType(Class<?> cls, Name n) {
629 int local = n.index();
630 Class<?> aclass = localClasses[local];
631 if (aclass != null && (aclass == cls || cls.isAssignableFrom(aclass))) {
632 return true; // type info is already present
633 } else if (aclass == null || aclass.isAssignableFrom(cls)) {
634 localClasses[local] = cls; // type info can be improved
635 }
636 return false;
637 }
638
639 private void emitReferenceCast(Class<?> cls, Object arg) {
640 Name writeBack = null; // local to write back result
641 if (arg instanceof Name n) {
642 if (lambdaForm.useCount(n) > 1) {
643 // This guy gets used more than once.
644 writeBack = n;
645 if (assertStaticType(cls, n)) {
646 return; // this cast was already performed
647 }
648 }
649 }
650 if (isStaticallyNameable(cls)) {
651 String sig = getInternalName(cls);
652 mv.visitTypeInsn(Opcodes.CHECKCAST, sig);
653 } else {
654 mv.visitFieldInsn(Opcodes.GETSTATIC, className, classData(cls), "Ljava/lang/Class;");
655 mv.visitInsn(Opcodes.SWAP);
656 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, CLS, "cast", LL_SIG, false);
657 if (Object[].class.isAssignableFrom(cls))
658 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJARY);
659 else if (PROFILE_LEVEL > 0)
660 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJ);
661 }
662 if (writeBack != null) {
663 mv.visitInsn(Opcodes.DUP);
664 emitAstoreInsn(writeBack.index());
665 }
666 }
667
668 /**
669 * Emits an actual return instruction conforming to the given return type.
670 */
671 private void emitReturnInsn(BasicType type) {
672 int opcode = switch (type) {
673 case I_TYPE -> Opcodes.IRETURN;
674 case J_TYPE -> Opcodes.LRETURN;
675 case F_TYPE -> Opcodes.FRETURN;
676 case D_TYPE -> Opcodes.DRETURN;
677 case L_TYPE -> Opcodes.ARETURN;
678 case V_TYPE -> Opcodes.RETURN;
679 default -> throw new InternalError("unknown return type: " + type);
680 };
681 mv.visitInsn(opcode);
682 }
683
684 private String getInternalName(Class<?> c) {
685 if (c == Object.class) return OBJ;
686 else if (c == Object[].class) return OBJARY;
687 else if (c == Class.class) return CLS;
688 else if (c == MethodHandle.class) return MH;
689 assert(VerifyAccess.isTypeVisible(c, Object.class)) : c.getName();
690
691 if (c == lastClass) {
692 return lastInternalName;
693 }
694 lastClass = c;
695 return lastInternalName = c.getName().replace('.', '/');
696 }
697
698 private static MemberName resolveFrom(String name, MethodType type, Class<?> holder) {
699 assert(!UNSAFE.shouldBeInitialized(holder)) : holder + "not initialized";
700 MemberName member = new MemberName(holder, name, type, REF_invokeStatic);
701 MemberName resolvedMember = MemberName.getFactory().resolveOrNull(REF_invokeStatic, member, holder, LM_TRUSTED);
702 traceLambdaForm(name, type, holder, resolvedMember);
703 return resolvedMember;
704 }
705
706 private static MemberName lookupPregenerated(LambdaForm form, MethodType invokerType) {
707 if (form.customized != null) {
708 // No pre-generated version for customized LF
709 return null;
710 }
711 String name = form.kind.methodName;
712 switch (form.kind) {
713 case BOUND_REINVOKER: {
714 name = name + "_" + BoundMethodHandle.speciesDataFor(form).key();
715 return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class);
716 }
717 case DELEGATE: return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class);
718 case ZERO: // fall-through
719 case IDENTITY: {
720 name = name + "_" + form.returnType().basicTypeChar();
721 return resolveFrom(name, invokerType, LambdaForm.Holder.class);
722 }
723 case EXACT_INVOKER: // fall-through
724 case EXACT_LINKER: // fall-through
725 case LINK_TO_CALL_SITE: // fall-through
726 case LINK_TO_TARGET_METHOD: // fall-through
727 case GENERIC_INVOKER: // fall-through
728 case GENERIC_LINKER: return resolveFrom(name, invokerType, Invokers.Holder.class);
729 case GET_REFERENCE: // fall-through
730 case GET_BOOLEAN: // fall-through
731 case GET_BYTE: // fall-through
732 case GET_CHAR: // fall-through
733 case GET_SHORT: // fall-through
734 case GET_INT: // fall-through
735 case GET_LONG: // fall-through
736 case GET_FLOAT: // fall-through
737 case GET_DOUBLE: // fall-through
738 case PUT_REFERENCE: // fall-through
739 case PUT_BOOLEAN: // fall-through
740 case PUT_BYTE: // fall-through
741 case PUT_CHAR: // fall-through
742 case PUT_SHORT: // fall-through
743 case PUT_INT: // fall-through
744 case PUT_LONG: // fall-through
745 case PUT_FLOAT: // fall-through
746 case PUT_DOUBLE: // fall-through
747 case DIRECT_NEW_INVOKE_SPECIAL: // fall-through
748 case DIRECT_INVOKE_INTERFACE: // fall-through
749 case DIRECT_INVOKE_SPECIAL: // fall-through
750 case DIRECT_INVOKE_SPECIAL_IFC: // fall-through
751 case DIRECT_INVOKE_STATIC: // fall-through
752 case DIRECT_INVOKE_STATIC_INIT: // fall-through
753 case DIRECT_INVOKE_VIRTUAL: return resolveFrom(name, invokerType, DirectMethodHandle.Holder.class);
754 }
755 return null;
756 }
757
758 /**
759 * Generate customized bytecode for a given LambdaForm.
760 */
761 static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) {
762 MemberName pregenerated = lookupPregenerated(form, invokerType);
763 if (pregenerated != null) return pregenerated; // pre-generated bytecode
764
765 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("MH", form, invokerType);
766 return g.loadMethod(g.generateCustomizedCodeBytes());
767 }
768
769 /** Generates code to check that actual receiver and LambdaForm matches */
770 private boolean checkActualReceiver() {
771 // Expects MethodHandle on the stack and actual receiver MethodHandle in slot #0
772 mv.visitInsn(Opcodes.DUP);
773 mv.visitVarInsn(Opcodes.ALOAD, localsMap[0]);
774 mv.visitMethodInsn(Opcodes.INVOKESTATIC, MHI, "assertSame", LLV_SIG, false);
775 return true;
776 }
777
778 static String className(String cn) {
779 assert checkClassName(cn): "Class not found: " + cn;
780 return cn;
781 }
782
783 static boolean checkClassName(String cn) {
784 Type tp = Type.getType(cn);
785 // additional sanity so only valid "L;" descriptors work
786 if (tp.getSort() != Type.OBJECT) {
787 return false;
788 }
789 try {
790 Class<?> c = Class.forName(tp.getClassName(), false, null);
791 return true;
792 } catch (ClassNotFoundException e) {
793 return false;
794 }
795 }
796
797 static final String DONTINLINE_SIG = className("Ljdk/internal/vm/annotation/DontInline;");
798 static final String FORCEINLINE_SIG = className("Ljdk/internal/vm/annotation/ForceInline;");
799 static final String HIDDEN_SIG = className("Ljdk/internal/vm/annotation/Hidden;");
800 static final String INJECTEDPROFILE_SIG = className("Ljava/lang/invoke/InjectedProfile;");
801 static final String LF_COMPILED_SIG = className("Ljava/lang/invoke/LambdaForm$Compiled;");
802
803 /**
804 * Generate an invoker method for the passed {@link LambdaForm}.
805 */
806 private byte[] generateCustomizedCodeBytes() {
807 classFilePrologue();
808 addMethod();
809 clinit(cw, className, classData);
810 bogusMethod(lambdaForm);
811
812 final byte[] classFile = toByteArray();
813 maybeDump(classFile);
814 return classFile;
815 }
816
817 void setClassWriter(ClassWriter cw) {
818 this.cw = cw;
819 }
820
821 void addMethod() {
822 methodPrologue();
823
824 // Suppress this method in backtraces displayed to the user.
825 mv.visitAnnotation(HIDDEN_SIG, true);
826
827 // Mark this method as a compiled LambdaForm
828 mv.visitAnnotation(LF_COMPILED_SIG, true);
829
830 if (lambdaForm.forceInline) {
831 // Force inlining of this invoker method.
832 mv.visitAnnotation(FORCEINLINE_SIG, true);
833 } else {
834 mv.visitAnnotation(DONTINLINE_SIG, true);
835 }
836
837 classData(lambdaForm); // keep LambdaForm instance & its compiled form lifetime tightly coupled.
838
839 if (lambdaForm.customized != null) {
840 // Since LambdaForm is customized for a particular MethodHandle, it's safe to substitute
841 // receiver MethodHandle (at slot #0) with an embedded constant and use it instead.
842 // It enables more efficient code generation in some situations, since embedded constants
843 // are compile-time constants for JIT compiler.
844 mv.visitFieldInsn(Opcodes.GETSTATIC, className, classData(lambdaForm.customized), MH_SIG);
845 mv.visitTypeInsn(Opcodes.CHECKCAST, MH);
846 assert(checkActualReceiver()); // expects MethodHandle on top of the stack
847 mv.visitVarInsn(Opcodes.ASTORE, localsMap[0]);
848 }
849
850 // iterate over the form's names, generating bytecode instructions for each
851 // start iterating at the first name following the arguments
852 Name onStack = null;
853 for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) {
854 Name name = lambdaForm.names[i];
855
856 emitStoreResult(onStack);
857 onStack = name; // unless otherwise modified below
858 MethodHandleImpl.Intrinsic intr = name.function.intrinsicName();
859 switch (intr) {
860 case SELECT_ALTERNATIVE:
861 assert lambdaForm.isSelectAlternative(i);
862 if (PROFILE_GWT) {
863 assert(name.arguments[0] instanceof Name &&
864 ((Name)name.arguments[0]).refersTo(MethodHandleImpl.class, "profileBoolean"));
865 mv.visitAnnotation(INJECTEDPROFILE_SIG, true);
866 }
867 onStack = emitSelectAlternative(name, lambdaForm.names[i+1]);
868 i++; // skip MH.invokeBasic of the selectAlternative result
869 continue;
870 case GUARD_WITH_CATCH:
871 assert lambdaForm.isGuardWithCatch(i);
872 onStack = emitGuardWithCatch(i);
873 i += 2; // jump to the end of GWC idiom
874 continue;
875 case TRY_FINALLY:
876 assert lambdaForm.isTryFinally(i);
877 onStack = emitTryFinally(i);
878 i += 2; // jump to the end of the TF idiom
879 continue;
880 case TABLE_SWITCH:
881 assert lambdaForm.isTableSwitch(i);
882 int numCases = (Integer) name.function.intrinsicData();
883 onStack = emitTableSwitch(i, numCases);
884 i += 2; // jump to the end of the TS idiom
885 continue;
886 case LOOP:
887 assert lambdaForm.isLoop(i);
888 onStack = emitLoop(i);
889 i += 2; // jump to the end of the LOOP idiom
890 continue;
891 case ARRAY_LOAD:
892 emitArrayLoad(name);
893 continue;
894 case ARRAY_STORE:
895 emitArrayStore(name);
896 continue;
897 case ARRAY_LENGTH:
898 emitArrayLength(name);
899 continue;
900 case IDENTITY:
901 assert(name.arguments.length == 1);
902 emitPushArguments(name, 0);
903 continue;
904 case ZERO:
905 assert(name.arguments.length == 0);
906 emitConst(name.type.basicTypeWrapper().zero());
907 continue;
908 case NONE:
909 // no intrinsic associated
910 break;
911 default:
912 throw newInternalError("Unknown intrinsic: "+intr);
913 }
914
915 MemberName member = name.function.member();
916 if (isStaticallyInvocable(member)) {
917 emitStaticInvoke(member, name);
918 } else {
919 emitInvoke(name);
920 }
921 }
922
923 // return statement
924 emitReturn(onStack);
925
926 methodEpilogue();
927 }
928
929 /*
930 * @throws BytecodeGenerationException if something goes wrong when
931 * generating the byte code
932 */
933 private byte[] toByteArray() {
934 try {
935 return cw.toByteArray();
936 } catch (RuntimeException e) {
937 throw new BytecodeGenerationException(e);
938 }
939 }
940
941 /**
942 * The BytecodeGenerationException.
943 */
944 @SuppressWarnings("serial")
945 static final class BytecodeGenerationException extends RuntimeException {
946 BytecodeGenerationException(Exception cause) {
947 super(cause);
948 }
949 }
950
951 void emitArrayLoad(Name name) { emitArrayOp(name, Opcodes.AALOAD); }
952 void emitArrayStore(Name name) { emitArrayOp(name, Opcodes.AASTORE); }
953 void emitArrayLength(Name name) { emitArrayOp(name, Opcodes.ARRAYLENGTH); }
954
955 void emitArrayOp(Name name, int arrayOpcode) {
956 assert arrayOpcode == Opcodes.AALOAD || arrayOpcode == Opcodes.AASTORE || arrayOpcode == Opcodes.ARRAYLENGTH;
957 Class<?> elementType = name.function.methodType().parameterType(0).getComponentType();
958 assert elementType != null;
959 emitPushArguments(name, 0);
960 if (arrayOpcode != Opcodes.ARRAYLENGTH && elementType.isPrimitive()) {
961 Wrapper w = Wrapper.forPrimitiveType(elementType);
962 arrayOpcode = arrayInsnOpcode(arrayTypeCode(w), arrayOpcode);
963 }
964 mv.visitInsn(arrayOpcode);
965 }
966
967 /**
968 * Emit an invoke for the given name.
969 */
970 void emitInvoke(Name name) {
971 assert(!name.isLinkerMethodInvoke()); // should use the static path for these
972 if (true) {
973 // push receiver
974 MethodHandle target = name.function.resolvedHandle();
975 assert(target != null) : name.exprString();
976 mv.visitFieldInsn(Opcodes.GETSTATIC, className, classData(target), MH_SIG);
977 emitReferenceCast(MethodHandle.class, target);
978 } else {
979 // load receiver
980 emitAloadInsn(0);
981 emitReferenceCast(MethodHandle.class, null);
982 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", LF_SIG);
983 mv.visitFieldInsn(Opcodes.GETFIELD, LF, "names", LFN_SIG);
984 // TODO more to come
985 }
986
987 // push arguments
988 emitPushArguments(name, 0);
989
990 // invocation
991 MethodType type = name.function.methodType();
992 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
993 }
994
995 private static final Class<?>[] STATICALLY_INVOCABLE_PACKAGES = {
996 // Sample classes from each package we are willing to bind to statically:
997 java.lang.Object.class,
998 java.util.Arrays.class,
999 jdk.internal.misc.Unsafe.class
1000 //MethodHandle.class already covered
1001 };
1002
1003 static boolean isStaticallyInvocable(NamedFunction ... functions) {
1004 for (NamedFunction nf : functions) {
1005 if (!isStaticallyInvocable(nf.member())) {
1006 return false;
1007 }
1008 }
1009 return true;
1010 }
1011
1012 static boolean isStaticallyInvocable(Name name) {
1013 return isStaticallyInvocable(name.function.member());
1014 }
1015
1016 static boolean isStaticallyInvocable(MemberName member) {
1017 if (member == null) return false;
1018 if (member.isConstructor()) return false;
1019 Class<?> cls = member.getDeclaringClass();
1020 // Fast-path non-private members declared by MethodHandles, which is a common
1021 // case
1022 if (MethodHandle.class.isAssignableFrom(cls) && !member.isPrivate()) {
1023 assert(isStaticallyInvocableType(member.getMethodOrFieldType()));
1024 return true;
1025 }
1026 if (cls.isArray() || cls.isPrimitive())
1027 return false; // FIXME
1028 if (cls.isAnonymousClass() || cls.isLocalClass())
1029 return false; // inner class of some sort
1030 if (cls.getClassLoader() != MethodHandle.class.getClassLoader())
1031 return false; // not on BCP
1032 if (cls.isHidden())
1033 return false;
1034 if (!isStaticallyInvocableType(member.getMethodOrFieldType()))
1035 return false;
1036 if (!member.isPrivate() && VerifyAccess.isSamePackage(MethodHandle.class, cls))
1037 return true; // in java.lang.invoke package
1038 if (member.isPublic() && isStaticallyNameable(cls))
1039 return true;
1040 return false;
1041 }
1042
1043 private static boolean isStaticallyInvocableType(MethodType mtype) {
1044 if (!isStaticallyNameable(mtype.returnType()))
1045 return false;
1046 for (Class<?> ptype : mtype.ptypes())
1047 if (!isStaticallyNameable(ptype))
1048 return false;
1049 return true;
1050 }
1051
1052 static boolean isStaticallyNameable(Class<?> cls) {
1053 if (cls == Object.class)
1054 return true;
1055 if (MethodHandle.class.isAssignableFrom(cls)) {
1056 assert(!cls.isHidden());
1057 return true;
1058 }
1059 while (cls.isArray())
1060 cls = cls.getComponentType();
1061 if (cls.isPrimitive())
1062 return true; // int[].class, for example
1063 if (cls.isHidden())
1064 return false;
1065 // could use VerifyAccess.isClassAccessible but the following is a safe approximation
1066 if (cls.getClassLoader() != Object.class.getClassLoader())
1067 return false;
1068 if (VerifyAccess.isSamePackage(MethodHandle.class, cls))
1069 return true;
1070 if (!Modifier.isPublic(cls.getModifiers()))
1071 return false;
1072 for (Class<?> pkgcls : STATICALLY_INVOCABLE_PACKAGES) {
1073 if (VerifyAccess.isSamePackage(pkgcls, cls))
1074 return true;
1075 }
1076 return false;
1077 }
1078
1079 void emitStaticInvoke(Name name) {
1080 emitStaticInvoke(name.function.member(), name);
1081 }
1082
1083 /**
1084 * Emit an invoke for the given name, using the MemberName directly.
1085 */
1086 void emitStaticInvoke(MemberName member, Name name) {
1087 assert(member.equals(name.function.member()));
1088 Class<?> defc = member.getDeclaringClass();
1089 String cname = getInternalName(defc);
1090 String mname = member.getName();
1091 String mtype;
1092 byte refKind = member.getReferenceKind();
1093 if (refKind == REF_invokeSpecial) {
1094 // in order to pass the verifier, we need to convert this to invokevirtual in all cases
1095 assert(member.canBeStaticallyBound()) : member;
1096 refKind = REF_invokeVirtual;
1097 }
1098
1099 assert(!(member.getDeclaringClass().isInterface() && refKind == REF_invokeVirtual));
1100
1101 // push arguments
1102 emitPushArguments(name, 0);
1103
1104 // invocation
1105 if (member.isMethod()) {
1106 mtype = member.getMethodType().toMethodDescriptorString();
1107 mv.visitMethodInsn(refKindOpcode(refKind), cname, mname, mtype,
1108 member.getDeclaringClass().isInterface());
1109 } else {
1110 mtype = MethodType.toFieldDescriptorString(member.getFieldType());
1111 mv.visitFieldInsn(refKindOpcode(refKind), cname, mname, mtype);
1112 }
1113 // Issue a type assertion for the result, so we can avoid casts later.
1114 if (name.type == L_TYPE) {
1115 Class<?> rtype = member.getInvocationType().returnType();
1116 assert(!rtype.isPrimitive());
1117 if (rtype != Object.class && !rtype.isInterface()) {
1118 assertStaticType(rtype, name);
1119 }
1120 }
1121 }
1122
1123 int refKindOpcode(byte refKind) {
1124 switch (refKind) {
1125 case REF_invokeVirtual: return Opcodes.INVOKEVIRTUAL;
1126 case REF_invokeStatic: return Opcodes.INVOKESTATIC;
1127 case REF_invokeSpecial: return Opcodes.INVOKESPECIAL;
1128 case REF_invokeInterface: return Opcodes.INVOKEINTERFACE;
1129 case REF_getField: return Opcodes.GETFIELD;
1130 case REF_putField: return Opcodes.PUTFIELD;
1131 case REF_getStatic: return Opcodes.GETSTATIC;
1132 case REF_putStatic: return Opcodes.PUTSTATIC;
1133 }
1134 throw new InternalError("refKind="+refKind);
1135 }
1136
1137 /**
1138 * Emit bytecode for the selectAlternative idiom.
1139 *
1140 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithTest):
1141 * <blockquote><pre>{@code
1142 * Lambda(a0:L,a1:I)=>{
1143 * t2:I=foo.test(a1:I);
1144 * t3:L=MethodHandleImpl.selectAlternative(t2:I,(MethodHandle(int)int),(MethodHandle(int)int));
1145 * t4:I=MethodHandle.invokeBasic(t3:L,a1:I);t4:I}
1146 * }</pre></blockquote>
1147 */
1148 private Name emitSelectAlternative(Name selectAlternativeName, Name invokeBasicName) {
1149 assert isStaticallyInvocable(invokeBasicName);
1150
1151 Name receiver = (Name) invokeBasicName.arguments[0];
1152
1153 Label L_fallback = new Label();
1154 Label L_done = new Label();
1155
1156 // load test result
1157 emitPushArgument(selectAlternativeName, 0);
1158
1159 // if_icmpne L_fallback
1160 mv.visitJumpInsn(Opcodes.IFEQ, L_fallback);
1161
1162 // invoke selectAlternativeName.arguments[1]
1163 Class<?>[] preForkClasses = localClasses.clone();
1164 emitPushArgument(selectAlternativeName, 1); // get 2nd argument of selectAlternative
1165 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
1166 emitStaticInvoke(invokeBasicName);
1167
1168 // goto L_done
1169 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1170
1171 // L_fallback:
1172 mv.visitLabel(L_fallback);
1173
1174 // invoke selectAlternativeName.arguments[2]
1175 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
1176 emitPushArgument(selectAlternativeName, 2); // get 3rd argument of selectAlternative
1177 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
1178 emitStaticInvoke(invokeBasicName);
1179
1180 // L_done:
1181 mv.visitLabel(L_done);
1182 // for now do not bother to merge typestate; just reset to the dominator state
1183 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
1184
1185 return invokeBasicName; // return what's on stack
1186 }
1187
1188 /**
1189 * Emit bytecode for the guardWithCatch idiom.
1190 *
1191 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithCatch):
1192 * <blockquote><pre>{@code
1193 * guardWithCatch=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{
1194 * t8:L=MethodHandle.invokeBasic(a4:L,a6:L,a7:L);
1195 * t9:L=MethodHandleImpl.guardWithCatch(a1:L,a2:L,a3:L,t8:L);
1196 * t10:I=MethodHandle.invokeBasic(a5:L,t9:L);t10:I}
1197 * }</pre></blockquote>
1198 *
1199 * It is compiled into bytecode equivalent of the following code:
1200 * <blockquote><pre>{@code
1201 * try {
1202 * return a1.invokeBasic(a6, a7);
1203 * } catch (Throwable e) {
1204 * if (!a2.isInstance(e)) throw e;
1205 * return a3.invokeBasic(ex, a6, a7);
1206 * }}</pre></blockquote>
1207 */
1208 private Name emitGuardWithCatch(int pos) {
1209 Name args = lambdaForm.names[pos];
1210 Name invoker = lambdaForm.names[pos+1];
1211 Name result = lambdaForm.names[pos+2];
1212
1213 Label L_startBlock = new Label();
1214 Label L_endBlock = new Label();
1215 Label L_handler = new Label();
1216 Label L_done = new Label();
1217
1218 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1219 MethodType type = args.function.resolvedHandle().type()
1220 .dropParameterTypes(0,1)
1221 .changeReturnType(returnType);
1222
1223 mv.visitTryCatchBlock(L_startBlock, L_endBlock, L_handler, "java/lang/Throwable");
1224
1225 // Normal case
1226 mv.visitLabel(L_startBlock);
1227 // load target
1228 emitPushArgument(invoker, 0);
1229 emitPushArguments(args, 1); // skip 1st argument: method handle
1230 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
1231 mv.visitLabel(L_endBlock);
1232 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1233
1234 // Exceptional case
1235 mv.visitLabel(L_handler);
1236
1237 // Check exception's type
1238 mv.visitInsn(Opcodes.DUP);
1239 // load exception class
1240 emitPushArgument(invoker, 1);
1241 mv.visitInsn(Opcodes.SWAP);
1242 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Class", "isInstance", "(Ljava/lang/Object;)Z", false);
1243 Label L_rethrow = new Label();
1244 mv.visitJumpInsn(Opcodes.IFEQ, L_rethrow);
1245
1246 // Invoke catcher
1247 // load catcher
1248 emitPushArgument(invoker, 2);
1249 mv.visitInsn(Opcodes.SWAP);
1250 emitPushArguments(args, 1); // skip 1st argument: method handle
1251 MethodType catcherType = type.insertParameterTypes(0, Throwable.class);
1252 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", catcherType.basicType().toMethodDescriptorString(), false);
1253 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1254
1255 mv.visitLabel(L_rethrow);
1256 mv.visitInsn(Opcodes.ATHROW);
1257
1258 mv.visitLabel(L_done);
1259
1260 return result;
1261 }
1262
1263 /**
1264 * Emit bytecode for the tryFinally idiom.
1265 * <p>
1266 * The pattern looks like (Cf. MethodHandleImpl.makeTryFinally):
1267 * <blockquote><pre>{@code
1268 * // a0: BMH
1269 * // a1: target, a2: cleanup
1270 * // a3: box, a4: unbox
1271 * // a5 (and following): arguments
1272 * tryFinally=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L)=>{
1273 * t6:L=MethodHandle.invokeBasic(a3:L,a5:L); // box the arguments into an Object[]
1274 * t7:L=MethodHandleImpl.tryFinally(a1:L,a2:L,t6:L); // call the tryFinally executor
1275 * t8:L=MethodHandle.invokeBasic(a4:L,t7:L);t8:L} // unbox the result; return the result
1276 * }</pre></blockquote>
1277 * <p>
1278 * It is compiled into bytecode equivalent to the following code:
1279 * <blockquote><pre>{@code
1280 * Throwable t;
1281 * Object r;
1282 * try {
1283 * r = a1.invokeBasic(a5);
1284 * } catch (Throwable thrown) {
1285 * t = thrown;
1286 * throw t;
1287 * } finally {
1288 * r = a2.invokeBasic(t, r, a5);
1289 * }
1290 * return r;
1291 * }</pre></blockquote>
1292 * <p>
1293 * Specifically, the bytecode will have the following form (the stack effects are given for the beginnings of
1294 * blocks, and for the situations after executing the given instruction - the code will have a slightly different
1295 * shape if the return type is {@code void}):
1296 * <blockquote><pre>{@code
1297 * TRY: (--)
1298 * load target (-- target)
1299 * load args (-- args... target)
1300 * INVOKEVIRTUAL MethodHandle.invokeBasic (depends)
1301 * FINALLY_NORMAL: (-- r_2nd* r)
1302 * store returned value (--)
1303 * load cleanup (-- cleanup)
1304 * ACONST_NULL (-- t cleanup)
1305 * load returned value (-- r_2nd* r t cleanup)
1306 * load args (-- args... r_2nd* r t cleanup)
1307 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r_2nd* r)
1308 * GOTO DONE
1309 * CATCH: (-- t)
1310 * DUP (-- t t)
1311 * FINALLY_EXCEPTIONAL: (-- t t)
1312 * load cleanup (-- cleanup t t)
1313 * SWAP (-- t cleanup t)
1314 * load default for r (-- r_2nd* r t cleanup t)
1315 * load args (-- args... r_2nd* r t cleanup t)
1316 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r_2nd* r t)
1317 * POP/POP2* (-- t)
1318 * ATHROW
1319 * DONE: (-- r)
1320 * }</pre></blockquote>
1321 * * = depends on whether the return type takes up 2 stack slots.
1322 */
1323 private Name emitTryFinally(int pos) {
1324 Name args = lambdaForm.names[pos];
1325 Name invoker = lambdaForm.names[pos+1];
1326 Name result = lambdaForm.names[pos+2];
1327
1328 Label lFrom = new Label();
1329 Label lTo = new Label();
1330 Label lCatch = new Label();
1331 Label lDone = new Label();
1332
1333 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1334 BasicType basicReturnType = BasicType.basicType(returnType);
1335 boolean isNonVoid = returnType != void.class;
1336
1337 MethodType type = args.function.resolvedHandle().type()
1338 .dropParameterTypes(0,1)
1339 .changeReturnType(returnType);
1340 MethodType cleanupType = type.insertParameterTypes(0, Throwable.class);
1341 if (isNonVoid) {
1342 cleanupType = cleanupType.insertParameterTypes(1, returnType);
1343 }
1344 String cleanupDesc = cleanupType.basicType().toMethodDescriptorString();
1345
1346 // exception handler table
1347 mv.visitTryCatchBlock(lFrom, lTo, lCatch, "java/lang/Throwable");
1348
1349 // TRY:
1350 mv.visitLabel(lFrom);
1351 emitPushArgument(invoker, 0); // load target
1352 emitPushArguments(args, 1); // load args (skip 0: method handle)
1353 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
1354 mv.visitLabel(lTo);
1355
1356 // FINALLY_NORMAL:
1357 int index = extendLocalsMap(new Class<?>[]{ returnType });
1358 if (isNonVoid) {
1359 emitStoreInsn(basicReturnType, index);
1360 }
1361 emitPushArgument(invoker, 1); // load cleanup
1362 mv.visitInsn(Opcodes.ACONST_NULL);
1363 if (isNonVoid) {
1364 emitLoadInsn(basicReturnType, index);
1365 }
1366 emitPushArguments(args, 1); // load args (skip 0: method handle)
1367 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", cleanupDesc, false);
1368 mv.visitJumpInsn(Opcodes.GOTO, lDone);
1369
1370 // CATCH:
1371 mv.visitLabel(lCatch);
1372 mv.visitInsn(Opcodes.DUP);
1373
1374 // FINALLY_EXCEPTIONAL:
1375 emitPushArgument(invoker, 1); // load cleanup
1376 mv.visitInsn(Opcodes.SWAP);
1377 if (isNonVoid) {
1378 emitZero(BasicType.basicType(returnType)); // load default for result
1379 }
1380 emitPushArguments(args, 1); // load args (skip 0: method handle)
1381 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", cleanupDesc, false);
1382 if (isNonVoid) {
1383 emitPopInsn(basicReturnType);
1384 }
1385 mv.visitInsn(Opcodes.ATHROW);
1386
1387 // DONE:
1388 mv.visitLabel(lDone);
1389
1390 return result;
1391 }
1392
1393 private void emitPopInsn(BasicType type) {
1394 mv.visitInsn(popInsnOpcode(type));
1395 }
1396
1397 private static int popInsnOpcode(BasicType type) {
1398 return switch (type) {
1399 case I_TYPE, F_TYPE, L_TYPE -> Opcodes.POP;
1400 case J_TYPE, D_TYPE -> Opcodes.POP2;
1401 default -> throw new InternalError("unknown type: " + type);
1402 };
1403 }
1404
1405 private Name emitTableSwitch(int pos, int numCases) {
1406 Name args = lambdaForm.names[pos];
1407 Name invoker = lambdaForm.names[pos + 1];
1408 Name result = lambdaForm.names[pos + 2];
1409
1410 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1411 MethodType caseType = args.function.resolvedHandle().type()
1412 .dropParameterTypes(0, 1) // drop collector
1413 .changeReturnType(returnType);
1414 String caseDescriptor = caseType.basicType().toMethodDescriptorString();
1415
1416 emitPushArgument(invoker, 2); // push cases
1417 mv.visitFieldInsn(Opcodes.GETFIELD, "java/lang/invoke/MethodHandleImpl$CasesHolder", "cases",
1418 "[Ljava/lang/invoke/MethodHandle;");
1419 int casesLocal = extendLocalsMap(new Class<?>[] { MethodHandle[].class });
1420 emitStoreInsn(L_TYPE, casesLocal);
1421
1422 Label endLabel = new Label();
1423 Label defaultLabel = new Label();
1424 Label[] caseLabels = new Label[numCases];
1425 for (int i = 0; i < caseLabels.length; i++) {
1426 caseLabels[i] = new Label();
1427 }
1428
1429 emitPushArgument(invoker, 0); // push switch input
1430 mv.visitTableSwitchInsn(0, numCases - 1, defaultLabel, caseLabels);
1431
1432 mv.visitLabel(defaultLabel);
1433 emitPushArgument(invoker, 1); // push default handle
1434 emitPushArguments(args, 1); // again, skip collector
1435 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", caseDescriptor, false);
1436 mv.visitJumpInsn(Opcodes.GOTO, endLabel);
1437
1438 for (int i = 0; i < numCases; i++) {
1439 mv.visitLabel(caseLabels[i]);
1440 // Load the particular case:
1441 emitLoadInsn(L_TYPE, casesLocal);
1442 emitIconstInsn(i);
1443 mv.visitInsn(Opcodes.AALOAD);
1444
1445 // invoke it:
1446 emitPushArguments(args, 1); // again, skip collector
1447 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", caseDescriptor, false);
1448
1449 mv.visitJumpInsn(Opcodes.GOTO, endLabel);
1450 }
1451
1452 mv.visitLabel(endLabel);
1453
1454 return result;
1455 }
1456
1457 /**
1458 * Emit bytecode for the loop idiom.
1459 * <p>
1460 * The pattern looks like (Cf. MethodHandleImpl.loop):
1461 * <blockquote><pre>{@code
1462 * // a0: BMH
1463 * // a1: LoopClauses (containing an array of arrays: inits, steps, preds, finis)
1464 * // a2: box, a3: unbox
1465 * // a4 (and following): arguments
1466 * loop=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L)=>{
1467 * t5:L=MethodHandle.invokeBasic(a2:L,a4:L); // box the arguments into an Object[]
1468 * t6:L=MethodHandleImpl.loop(bt:L,a1:L,t5:L); // call the loop executor (with supplied types in bt)
1469 * t7:L=MethodHandle.invokeBasic(a3:L,t6:L);t7:L} // unbox the result; return the result
1470 * }</pre></blockquote>
1471 * <p>
1472 * It is compiled into bytecode equivalent to the code seen in {@link MethodHandleImpl#loop(BasicType[],
1473 * MethodHandleImpl.LoopClauses, Object...)}, with the difference that no arrays
1474 * will be used for local state storage. Instead, the local state will be mapped to actual stack slots.
1475 * <p>
1476 * Bytecode generation applies an unrolling scheme to enable better bytecode generation regarding local state type
1477 * handling. The generated bytecode will have the following form ({@code void} types are ignored for convenience).
1478 * Assume there are {@code C} clauses in the loop.
1479 * <blockquote><pre>{@code
1480 * PREINIT: ALOAD_1
1481 * CHECKCAST LoopClauses
1482 * GETFIELD LoopClauses.clauses
1483 * ASTORE clauseDataIndex // place the clauses 2-dimensional array on the stack
1484 * INIT: (INIT_SEQ for clause 1)
1485 * ...
1486 * (INIT_SEQ for clause C)
1487 * LOOP: (LOOP_SEQ for clause 1)
1488 * ...
1489 * (LOOP_SEQ for clause C)
1490 * GOTO LOOP
1491 * DONE: ...
1492 * }</pre></blockquote>
1493 * <p>
1494 * The {@code INIT_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has
1495 * the following shape. Assume slot {@code vx} is used to hold the state for clause {@code x}.
1496 * <blockquote><pre>{@code
1497 * INIT_SEQ_x: ALOAD clauseDataIndex
1498 * ICONST_0
1499 * AALOAD // load the inits array
1500 * ICONST x
1501 * AALOAD // load the init handle for clause x
1502 * load args
1503 * INVOKEVIRTUAL MethodHandle.invokeBasic
1504 * store vx
1505 * }</pre></blockquote>
1506 * <p>
1507 * The {@code LOOP_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has
1508 * the following shape. Again, assume slot {@code vx} is used to hold the state for clause {@code x}.
1509 * <blockquote><pre>{@code
1510 * LOOP_SEQ_x: ALOAD clauseDataIndex
1511 * ICONST_1
1512 * AALOAD // load the steps array
1513 * ICONST x
1514 * AALOAD // load the step handle for clause x
1515 * load locals
1516 * load args
1517 * INVOKEVIRTUAL MethodHandle.invokeBasic
1518 * store vx
1519 * ALOAD clauseDataIndex
1520 * ICONST_2
1521 * AALOAD // load the preds array
1522 * ICONST x
1523 * AALOAD // load the pred handle for clause x
1524 * load locals
1525 * load args
1526 * INVOKEVIRTUAL MethodHandle.invokeBasic
1527 * IFNE LOOP_SEQ_x+1 // predicate returned false -> jump to next clause
1528 * ALOAD clauseDataIndex
1529 * ICONST_3
1530 * AALOAD // load the finis array
1531 * ICONST x
1532 * AALOAD // load the fini handle for clause x
1533 * load locals
1534 * load args
1535 * INVOKEVIRTUAL MethodHandle.invokeBasic
1536 * GOTO DONE // jump beyond end of clauses to return from loop
1537 * }</pre></blockquote>
1538 */
1539 private Name emitLoop(int pos) {
1540 Name args = lambdaForm.names[pos];
1541 Name invoker = lambdaForm.names[pos+1];
1542 Name result = lambdaForm.names[pos+2];
1543
1544 // extract clause and loop-local state types
1545 // find the type info in the loop invocation
1546 BasicType[] loopClauseTypes = (BasicType[]) invoker.arguments[0];
1547 Class<?>[] loopLocalStateTypes = Stream.of(loopClauseTypes).
1548 filter(bt -> bt != BasicType.V_TYPE).map(BasicType::basicTypeClass).toArray(Class<?>[]::new);
1549 Class<?>[] localTypes = new Class<?>[loopLocalStateTypes.length + 1];
1550 localTypes[0] = MethodHandleImpl.LoopClauses.class;
1551 System.arraycopy(loopLocalStateTypes, 0, localTypes, 1, loopLocalStateTypes.length);
1552
1553 final int clauseDataIndex = extendLocalsMap(localTypes);
1554 final int firstLoopStateIndex = clauseDataIndex + 1;
1555
1556 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1557 MethodType loopType = args.function.resolvedHandle().type()
1558 .dropParameterTypes(0,1)
1559 .changeReturnType(returnType);
1560 MethodType loopHandleType = loopType.insertParameterTypes(0, loopLocalStateTypes);
1561 MethodType predType = loopHandleType.changeReturnType(boolean.class);
1562 MethodType finiType = loopHandleType;
1563
1564 final int nClauses = loopClauseTypes.length;
1565
1566 // indices to invoker arguments to load method handle arrays
1567 final int inits = 1;
1568 final int steps = 2;
1569 final int preds = 3;
1570 final int finis = 4;
1571
1572 Label lLoop = new Label();
1573 Label lDone = new Label();
1574 Label lNext;
1575
1576 // PREINIT:
1577 emitPushArgument(MethodHandleImpl.LoopClauses.class, invoker.arguments[1]);
1578 mv.visitFieldInsn(Opcodes.GETFIELD, LOOP_CLAUSES, "clauses", MHARY2);
1579 emitAstoreInsn(clauseDataIndex);
1580
1581 // INIT:
1582 for (int c = 0, state = 0; c < nClauses; ++c) {
1583 MethodType cInitType = loopType.changeReturnType(loopClauseTypes[c].basicTypeClass());
1584 emitLoopHandleInvoke(invoker, inits, c, args, false, cInitType, loopLocalStateTypes, clauseDataIndex,
1585 firstLoopStateIndex);
1586 if (cInitType.returnType() != void.class) {
1587 emitStoreInsn(BasicType.basicType(cInitType.returnType()), firstLoopStateIndex + state);
1588 ++state;
1589 }
1590 }
1591
1592 // LOOP:
1593 mv.visitLabel(lLoop);
1594
1595 for (int c = 0, state = 0; c < nClauses; ++c) {
1596 lNext = new Label();
1597
1598 MethodType stepType = loopHandleType.changeReturnType(loopClauseTypes[c].basicTypeClass());
1599 boolean isVoid = stepType.returnType() == void.class;
1600
1601 // invoke loop step
1602 emitLoopHandleInvoke(invoker, steps, c, args, true, stepType, loopLocalStateTypes, clauseDataIndex,
1603 firstLoopStateIndex);
1604 if (!isVoid) {
1605 emitStoreInsn(BasicType.basicType(stepType.returnType()), firstLoopStateIndex + state);
1606 ++state;
1607 }
1608
1609 // invoke loop predicate
1610 emitLoopHandleInvoke(invoker, preds, c, args, true, predType, loopLocalStateTypes, clauseDataIndex,
1611 firstLoopStateIndex);
1612 mv.visitJumpInsn(Opcodes.IFNE, lNext);
1613
1614 // invoke fini
1615 emitLoopHandleInvoke(invoker, finis, c, args, true, finiType, loopLocalStateTypes, clauseDataIndex,
1616 firstLoopStateIndex);
1617 mv.visitJumpInsn(Opcodes.GOTO, lDone);
1618
1619 // this is the beginning of the next loop clause
1620 mv.visitLabel(lNext);
1621 }
1622
1623 mv.visitJumpInsn(Opcodes.GOTO, lLoop);
1624
1625 // DONE:
1626 mv.visitLabel(lDone);
1627
1628 return result;
1629 }
1630
1631 private int extendLocalsMap(Class<?>[] types) {
1632 int firstSlot = localsMap.length - 1;
1633 localsMap = Arrays.copyOf(localsMap, localsMap.length + types.length);
1634 localClasses = Arrays.copyOf(localClasses, localClasses.length + types.length);
1635 System.arraycopy(types, 0, localClasses, firstSlot, types.length);
1636 int index = localsMap[firstSlot - 1] + 1;
1637 int lastSlots = 0;
1638 for (int i = 0; i < types.length; ++i) {
1639 localsMap[firstSlot + i] = index;
1640 lastSlots = BasicType.basicType(localClasses[firstSlot + i]).basicTypeSlots();
1641 index += lastSlots;
1642 }
1643 localsMap[localsMap.length - 1] = index - lastSlots;
1644 return firstSlot;
1645 }
1646
1647 private void emitLoopHandleInvoke(Name holder, int handles, int clause, Name args, boolean pushLocalState,
1648 MethodType type, Class<?>[] loopLocalStateTypes, int clauseDataSlot,
1649 int firstLoopStateSlot) {
1650 // load handle for clause
1651 emitPushClauseArray(clauseDataSlot, handles);
1652 emitIconstInsn(clause);
1653 mv.visitInsn(Opcodes.AALOAD);
1654 // load loop state (preceding the other arguments)
1655 if (pushLocalState) {
1656 for (int s = 0; s < loopLocalStateTypes.length; ++s) {
1657 emitLoadInsn(BasicType.basicType(loopLocalStateTypes[s]), firstLoopStateSlot + s);
1658 }
1659 }
1660 // load loop args (skip 0: method handle)
1661 emitPushArguments(args, 1);
1662 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.toMethodDescriptorString(), false);
1663 }
1664
1665 private void emitPushClauseArray(int clauseDataSlot, int which) {
1666 emitAloadInsn(clauseDataSlot);
1667 emitIconstInsn(which - 1);
1668 mv.visitInsn(Opcodes.AALOAD);
1669 }
1670
1671 private void emitZero(BasicType type) {
1672 mv.visitInsn(switch (type) {
1673 case I_TYPE -> Opcodes.ICONST_0;
1674 case J_TYPE -> Opcodes.LCONST_0;
1675 case F_TYPE -> Opcodes.FCONST_0;
1676 case D_TYPE -> Opcodes.DCONST_0;
1677 case L_TYPE -> Opcodes.ACONST_NULL;
1678 default -> throw new InternalError("unknown type: " + type);
1679 });
1680 }
1681
1682 private void emitPushArguments(Name args, int start) {
1683 MethodType type = args.function.methodType();
1684 for (int i = start; i < args.arguments.length; i++) {
1685 emitPushArgument(type.parameterType(i), args.arguments[i]);
1686 }
1687 }
1688
1689 private void emitPushArgument(Name name, int paramIndex) {
1690 Object arg = name.arguments[paramIndex];
1691 Class<?> ptype = name.function.methodType().parameterType(paramIndex);
1692 emitPushArgument(ptype, arg);
1693 }
1694
1695 private void emitPushArgument(Class<?> ptype, Object arg) {
1696 BasicType bptype = basicType(ptype);
1697 if (arg instanceof Name n) {
1698 emitLoadInsn(n.type, n.index());
1699 emitImplicitConversion(n.type, ptype, n);
1700 } else if (arg == null && bptype == L_TYPE) {
1701 mv.visitInsn(Opcodes.ACONST_NULL);
1702 } else if (arg instanceof String && bptype == L_TYPE) {
1703 mv.visitLdcInsn(arg);
1704 } else {
1705 if (Wrapper.isWrapperType(arg.getClass()) && bptype != L_TYPE) {
1706 emitConst(arg);
1707 } else {
1708 mv.visitFieldInsn(Opcodes.GETSTATIC, className, classData(arg), "Ljava/lang/Object;");
1709 emitImplicitConversion(L_TYPE, ptype, arg);
1710 }
1711 }
1712 }
1713
1714 /**
1715 * Store the name to its local, if necessary.
1716 */
1717 private void emitStoreResult(Name name) {
1718 if (name != null && name.type != V_TYPE) {
1719 // non-void: actually assign
1720 emitStoreInsn(name.type, name.index());
1721 }
1722 }
1723
1724 /**
1725 * Emits a return statement from a LF invoker. If required, the result type is cast to the correct return type.
1726 */
1727 private void emitReturn(Name onStack) {
1728 // return statement
1729 Class<?> rclass = invokerType.returnType();
1730 BasicType rtype = lambdaForm.returnType();
1731 assert(rtype == basicType(rclass)); // must agree
1732 if (rtype == V_TYPE) {
1733 // void
1734 mv.visitInsn(Opcodes.RETURN);
1735 // it doesn't matter what rclass is; the JVM will discard any value
1736 } else {
1737 LambdaForm.Name rn = lambdaForm.names[lambdaForm.result];
1738
1739 // put return value on the stack if it is not already there
1740 if (rn != onStack) {
1741 emitLoadInsn(rtype, lambdaForm.result);
1742 }
1743
1744 emitImplicitConversion(rtype, rclass, rn);
1745
1746 // generate actual return statement
1747 emitReturnInsn(rtype);
1748 }
1749 }
1750
1751 /**
1752 * Emit a type conversion bytecode casting from "from" to "to".
1753 */
1754 private void emitPrimCast(Wrapper from, Wrapper to) {
1755 // Here's how.
1756 // - indicates forbidden
1757 // <-> indicates implicit
1758 // to ----> boolean byte short char int long float double
1759 // from boolean <-> - - - - - - -
1760 // byte - <-> i2s i2c <-> i2l i2f i2d
1761 // short - i2b <-> i2c <-> i2l i2f i2d
1762 // char - i2b i2s <-> <-> i2l i2f i2d
1763 // int - i2b i2s i2c <-> i2l i2f i2d
1764 // long - l2i,i2b l2i,i2s l2i,i2c l2i <-> l2f l2d
1765 // float - f2i,i2b f2i,i2s f2i,i2c f2i f2l <-> f2d
1766 // double - d2i,i2b d2i,i2s d2i,i2c d2i d2l d2f <->
1767 if (from == to) {
1768 // no cast required, should be dead code anyway
1769 return;
1770 }
1771 if (from.isSubwordOrInt()) {
1772 // cast from {byte,short,char,int} to anything
1773 emitI2X(to);
1774 } else {
1775 // cast from {long,float,double} to anything
1776 if (to.isSubwordOrInt()) {
1777 // cast to {byte,short,char,int}
1778 emitX2I(from);
1779 if (to.bitWidth() < 32) {
1780 // targets other than int require another conversion
1781 emitI2X(to);
1782 }
1783 } else {
1784 // cast to {long,float,double} - this is verbose
1785 boolean error = false;
1786 switch (from) {
1787 case LONG -> {
1788 switch (to) {
1789 case FLOAT -> mv.visitInsn(Opcodes.L2F);
1790 case DOUBLE -> mv.visitInsn(Opcodes.L2D);
1791 default -> error = true;
1792 }
1793 }
1794 case FLOAT -> {
1795 switch (to) {
1796 case LONG -> mv.visitInsn(Opcodes.F2L);
1797 case DOUBLE -> mv.visitInsn(Opcodes.F2D);
1798 default -> error = true;
1799 }
1800 }
1801 case DOUBLE -> {
1802 switch (to) {
1803 case LONG -> mv.visitInsn(Opcodes.D2L);
1804 case FLOAT -> mv.visitInsn(Opcodes.D2F);
1805 default -> error = true;
1806 }
1807 }
1808 default -> error = true;
1809 }
1810 if (error) {
1811 throw new IllegalStateException("unhandled prim cast: " + from + "2" + to);
1812 }
1813 }
1814 }
1815 }
1816
1817 private void emitI2X(Wrapper type) {
1818 switch (type) {
1819 case BYTE: mv.visitInsn(Opcodes.I2B); break;
1820 case SHORT: mv.visitInsn(Opcodes.I2S); break;
1821 case CHAR: mv.visitInsn(Opcodes.I2C); break;
1822 case INT: /* naught */ break;
1823 case LONG: mv.visitInsn(Opcodes.I2L); break;
1824 case FLOAT: mv.visitInsn(Opcodes.I2F); break;
1825 case DOUBLE: mv.visitInsn(Opcodes.I2D); break;
1826 case BOOLEAN:
1827 // For compatibility with ValueConversions and explicitCastArguments:
1828 mv.visitInsn(Opcodes.ICONST_1);
1829 mv.visitInsn(Opcodes.IAND);
1830 break;
1831 default: throw new InternalError("unknown type: " + type);
1832 }
1833 }
1834
1835 private void emitX2I(Wrapper type) {
1836 switch (type) {
1837 case LONG -> mv.visitInsn(Opcodes.L2I);
1838 case FLOAT -> mv.visitInsn(Opcodes.F2I);
1839 case DOUBLE -> mv.visitInsn(Opcodes.D2I);
1840 default -> throw new InternalError("unknown type: " + type);
1841 }
1842 }
1843
1844 /**
1845 * Generate bytecode for a LambdaForm.vmentry which calls interpretWithArguments.
1846 */
1847 static MemberName generateLambdaFormInterpreterEntryPoint(MethodType mt) {
1848 assert(isValidSignature(basicTypeSignature(mt)));
1849 String name = "interpret_"+basicTypeChar(mt.returnType());
1850 MethodType type = mt; // includes leading argument
1851 type = type.changeParameterType(0, MethodHandle.class);
1852 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("LFI", name, type);
1853 return g.loadMethod(g.generateLambdaFormInterpreterEntryPointBytes());
1854 }
1855
1856 private byte[] generateLambdaFormInterpreterEntryPointBytes() {
1857 classFilePrologue();
1858 methodPrologue();
1859
1860 // Suppress this method in backtraces displayed to the user.
1861 mv.visitAnnotation(HIDDEN_SIG, true);
1862
1863 // Don't inline the interpreter entry.
1864 mv.visitAnnotation(DONTINLINE_SIG, true);
1865
1866 // create parameter array
1867 emitIconstInsn(invokerType.parameterCount());
1868 mv.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object");
1869
1870 // fill parameter array
1871 for (int i = 0; i < invokerType.parameterCount(); i++) {
1872 Class<?> ptype = invokerType.parameterType(i);
1873 mv.visitInsn(Opcodes.DUP);
1874 emitIconstInsn(i);
1875 emitLoadInsn(basicType(ptype), i);
1876 // box if primitive type
1877 if (ptype.isPrimitive()) {
1878 emitBoxing(Wrapper.forPrimitiveType(ptype));
1879 }
1880 mv.visitInsn(Opcodes.AASTORE);
1881 }
1882 // invoke
1883 emitAloadInsn(0);
1884 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", "Ljava/lang/invoke/LambdaForm;");
1885 mv.visitInsn(Opcodes.SWAP); // swap form and array; avoid local variable
1886 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, LF, "interpretWithArguments", "([Ljava/lang/Object;)Ljava/lang/Object;", false);
1887
1888 // maybe unbox
1889 Class<?> rtype = invokerType.returnType();
1890 if (rtype.isPrimitive() && rtype != void.class) {
1891 emitUnboxing(Wrapper.forPrimitiveType(rtype));
1892 }
1893
1894 // return statement
1895 emitReturnInsn(basicType(rtype));
1896
1897 methodEpilogue();
1898 clinit(cw, className, classData);
1899 bogusMethod(invokerType);
1900
1901 final byte[] classFile = cw.toByteArray();
1902 maybeDump(classFile);
1903 return classFile;
1904 }
1905
1906 /**
1907 * Generate bytecode for a NamedFunction invoker.
1908 */
1909 static MemberName generateNamedFunctionInvoker(MethodTypeForm typeForm) {
1910 MethodType invokerType = NamedFunction.INVOKER_METHOD_TYPE;
1911 String invokerName = "invoke_" + shortenSignature(basicTypeSignature(typeForm.erasedType()));
1912 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("NFI", invokerName, invokerType);
1913 return g.loadMethod(g.generateNamedFunctionInvokerImpl(typeForm));
1914 }
1915
1916 private byte[] generateNamedFunctionInvokerImpl(MethodTypeForm typeForm) {
1917 MethodType dstType = typeForm.erasedType();
1918 classFilePrologue();
1919 methodPrologue();
1920
1921 // Suppress this method in backtraces displayed to the user.
1922 mv.visitAnnotation(HIDDEN_SIG, true);
1923
1924 // Force inlining of this invoker method.
1925 mv.visitAnnotation(FORCEINLINE_SIG, true);
1926
1927 // Load receiver
1928 emitAloadInsn(0);
1929
1930 // Load arguments from array
1931 for (int i = 0; i < dstType.parameterCount(); i++) {
1932 emitAloadInsn(1);
1933 emitIconstInsn(i);
1934 mv.visitInsn(Opcodes.AALOAD);
1935
1936 // Maybe unbox
1937 Class<?> dptype = dstType.parameterType(i);
1938 if (dptype.isPrimitive()) {
1939 Wrapper dstWrapper = Wrapper.forBasicType(dptype);
1940 Wrapper srcWrapper = dstWrapper.isSubwordOrInt() ? Wrapper.INT : dstWrapper; // narrow subword from int
1941 emitUnboxing(srcWrapper);
1942 emitPrimCast(srcWrapper, dstWrapper);
1943 }
1944 }
1945
1946 // Invoke
1947 String targetDesc = dstType.basicType().toMethodDescriptorString();
1948 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", targetDesc, false);
1949
1950 // Box primitive types
1951 Class<?> rtype = dstType.returnType();
1952 if (rtype != void.class && rtype.isPrimitive()) {
1953 Wrapper srcWrapper = Wrapper.forBasicType(rtype);
1954 Wrapper dstWrapper = srcWrapper.isSubwordOrInt() ? Wrapper.INT : srcWrapper; // widen subword to int
1955 // boolean casts not allowed
1956 emitPrimCast(srcWrapper, dstWrapper);
1957 emitBoxing(dstWrapper);
1958 }
1959
1960 // If the return type is void we return a null reference.
1961 if (rtype == void.class) {
1962 mv.visitInsn(Opcodes.ACONST_NULL);
1963 }
1964 emitReturnInsn(L_TYPE); // NOTE: NamedFunction invokers always return a reference value.
1965
1966 methodEpilogue();
1967 clinit(cw, className, classData);
1968 bogusMethod(dstType);
1969
1970 final byte[] classFile = cw.toByteArray();
1971 maybeDump(classFile);
1972 return classFile;
1973 }
1974
1975 /**
1976 * Emit a bogus method that just loads some string constants. This is to get the constants into the constant pool
1977 * for debugging purposes.
1978 */
1979 private void bogusMethod(Object os) {
1980 if (DUMP_CLASS_FILES) {
1981 mv = cw.visitMethod(Opcodes.ACC_STATIC, "dummy", "()V", null, null);
1982 mv.visitLdcInsn(os.toString());
1983 mv.visitInsn(Opcodes.POP);
1984 mv.visitInsn(Opcodes.RETURN);
1985 mv.visitMaxs(0, 0);
1986 mv.visitEnd();
1987 }
1988 }
1989 }