1 /*
2 * Copyright (c) 2012, 2021, 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 List<Object> classDataValues() {
289 final List<ClassData> cd = classData;
290 return switch(cd.size()) {
291 case 0 -> List.of();
292 case 1 -> List.of(cd.get(0).value);
293 case 2 -> List.of(cd.get(0).value, cd.get(1).value);
294 case 3 -> List.of(cd.get(0).value, cd.get(1).value, cd.get(2).value);
295 case 4 -> List.of(cd.get(0).value, cd.get(1).value, cd.get(2).value, cd.get(3).value);
296 default -> {
297 Object[] data = new Object[classData.size()];
298 for (int i = 0; i < classData.size(); i++) {
299 data[i] = classData.get(i).value;
300 }
301 yield List.of(data);
302 }
303 };
304 }
305
306 private static String debugString(Object arg) {
307 if (arg instanceof MethodHandle mh) {
308 MemberName member = mh.internalMemberName();
309 if (member != null)
310 return member.toString();
311 return mh.debugString();
312 }
313 return arg.toString();
314 }
315
316 /**
317 * Extract the MemberName of a newly-defined method.
318 */
319 private MemberName loadMethod(byte[] classFile) {
320 Class<?> invokerClass = LOOKUP.makeHiddenClassDefiner(className, classFile, Set.of())
321 .defineClass(true, classDataValues());
322 return resolveInvokerMember(invokerClass, invokerName, invokerType);
323 }
324
325 private static MemberName resolveInvokerMember(Class<?> invokerClass, String name, MethodType type) {
326 MemberName member = new MemberName(invokerClass, name, type, REF_invokeStatic);
327 try {
328 member = MEMBERNAME_FACTORY.resolveOrFail(REF_invokeStatic, member,
329 HOST_CLASS, LM_TRUSTED,
330 ReflectiveOperationException.class);
331 } catch (ReflectiveOperationException e) {
332 throw newInternalError(e);
333 }
334 return member;
335 }
336
337 /**
338 * Set up class file generation.
339 */
340 private ClassWriter classFilePrologue() {
341 final int NOT_ACC_PUBLIC = 0; // not ACC_PUBLIC
342 ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
343 setClassWriter(cw);
344 cw.visit(CLASSFILE_VERSION, NOT_ACC_PUBLIC + Opcodes.ACC_FINAL + Opcodes.ACC_SUPER,
345 className, null, INVOKER_SUPER_NAME, null);
346 cw.visitSource(SOURCE_PREFIX + name, null);
347 return cw;
348 }
349
350 private void methodPrologue() {
351 String invokerDesc = invokerType.toMethodDescriptorString();
352 mv = cw.visitMethod(Opcodes.ACC_STATIC, invokerName, invokerDesc, null, null);
353 }
354
355 /**
356 * Tear down class file generation.
357 */
358 private void methodEpilogue() {
359 mv.visitMaxs(0, 0);
360 mv.visitEnd();
361 }
362
363 /*
364 * <clinit> to initialize the static final fields with the live class data
365 * LambdaForms can't use condy due to bootstrapping issue.
366 */
367 static void clinit(ClassWriter cw, String className, List<ClassData> classData) {
368 if (classData.isEmpty())
369 return;
370
371 for (ClassData p : classData) {
372 // add the static field
373 FieldVisitor fv = cw.visitField(Opcodes.ACC_STATIC|Opcodes.ACC_FINAL, p.name, p.desc, null, null);
374 fv.visitEnd();
375 }
376
377 MethodVisitor mv = cw.visitMethod(Opcodes.ACC_STATIC, "<clinit>", "()V", null, null);
378 mv.visitCode();
379 mv.visitLdcInsn(Type.getType("L" + className + ";"));
380 mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/invoke/MethodHandles",
381 "classData", "(Ljava/lang/Class;)Ljava/lang/Object;", false);
382 // we should optimize one single element case that does not need to create a List
383 mv.visitTypeInsn(Opcodes.CHECKCAST, "java/util/List");
384 mv.visitVarInsn(Opcodes.ASTORE, 0);
385 int index = 0;
386 for (ClassData p : classData) {
387 // initialize the static field
388 mv.visitVarInsn(Opcodes.ALOAD, 0);
389 emitIconstInsn(mv, index++);
390 mv.visitMethodInsn(Opcodes.INVOKEINTERFACE, "java/util/List",
391 "get", "(I)Ljava/lang/Object;", true);
392 mv.visitTypeInsn(Opcodes.CHECKCAST, p.desc.substring(1, p.desc.length()-1));
393 mv.visitFieldInsn(Opcodes.PUTSTATIC, className, p.name, p.desc);
394 }
395 mv.visitInsn(Opcodes.RETURN);
396 mv.visitMaxs(2, 1);
397 mv.visitEnd();
398 }
399
400 /*
401 * Low-level emit helpers.
402 */
403 private void emitConst(Object con) {
404 if (con == null) {
405 mv.visitInsn(Opcodes.ACONST_NULL);
406 return;
407 }
408 if (con instanceof Integer) {
409 emitIconstInsn((int) con);
410 return;
411 }
412 if (con instanceof Byte) {
413 emitIconstInsn((byte)con);
414 return;
415 }
416 if (con instanceof Short) {
417 emitIconstInsn((short)con);
418 return;
419 }
420 if (con instanceof Character) {
421 emitIconstInsn((char)con);
422 return;
423 }
424 if (con instanceof Long) {
425 long x = (long) con;
426 short sx = (short)x;
427 if (x == sx) {
428 if (sx >= 0 && sx <= 1) {
429 mv.visitInsn(Opcodes.LCONST_0 + (int) sx);
430 } else {
431 emitIconstInsn((int) x);
432 mv.visitInsn(Opcodes.I2L);
433 }
434 return;
435 }
436 }
437 if (con instanceof Float) {
438 float x = (float) con;
439 short sx = (short)x;
440 if (x == sx) {
441 if (sx >= 0 && sx <= 2) {
442 mv.visitInsn(Opcodes.FCONST_0 + (int) sx);
443 } else {
444 emitIconstInsn((int) x);
445 mv.visitInsn(Opcodes.I2F);
446 }
447 return;
448 }
449 }
450 if (con instanceof Double) {
451 double x = (double) con;
452 short sx = (short)x;
453 if (x == sx) {
454 if (sx >= 0 && sx <= 1) {
455 mv.visitInsn(Opcodes.DCONST_0 + (int) sx);
456 } else {
457 emitIconstInsn((int) x);
458 mv.visitInsn(Opcodes.I2D);
459 }
460 return;
461 }
462 }
463 if (con instanceof Boolean) {
464 emitIconstInsn((boolean) con ? 1 : 0);
465 return;
466 }
467 // fall through:
468 mv.visitLdcInsn(con);
469 }
470
471 private void emitIconstInsn(final int cst) {
472 emitIconstInsn(mv, cst);
473 }
474
475 private static void emitIconstInsn(MethodVisitor mv, int cst) {
476 if (cst >= -1 && cst <= 5) {
477 mv.visitInsn(Opcodes.ICONST_0 + cst);
478 } else if (cst >= Byte.MIN_VALUE && cst <= Byte.MAX_VALUE) {
479 mv.visitIntInsn(Opcodes.BIPUSH, cst);
480 } else if (cst >= Short.MIN_VALUE && cst <= Short.MAX_VALUE) {
481 mv.visitIntInsn(Opcodes.SIPUSH, cst);
482 } else {
483 mv.visitLdcInsn(cst);
484 }
485 }
486
487 /*
488 * NOTE: These load/store methods use the localsMap to find the correct index!
489 */
490 private void emitLoadInsn(BasicType type, int index) {
491 int opcode = loadInsnOpcode(type);
492 mv.visitVarInsn(opcode, localsMap[index]);
493 }
494
495 private int loadInsnOpcode(BasicType type) throws InternalError {
496 return switch (type) {
497 case I_TYPE -> Opcodes.ILOAD;
498 case J_TYPE -> Opcodes.LLOAD;
499 case F_TYPE -> Opcodes.FLOAD;
500 case D_TYPE -> Opcodes.DLOAD;
501 case L_TYPE -> Opcodes.ALOAD;
502 default -> throw new InternalError("unknown type: " + type);
503 };
504 }
505 private void emitAloadInsn(int index) {
506 emitLoadInsn(L_TYPE, index);
507 }
508
509 private void emitStoreInsn(BasicType type, int index) {
510 int opcode = storeInsnOpcode(type);
511 mv.visitVarInsn(opcode, localsMap[index]);
512 }
513
514 private int storeInsnOpcode(BasicType type) throws InternalError {
515 return switch (type) {
516 case I_TYPE -> Opcodes.ISTORE;
517 case J_TYPE -> Opcodes.LSTORE;
518 case F_TYPE -> Opcodes.FSTORE;
519 case D_TYPE -> Opcodes.DSTORE;
520 case L_TYPE -> Opcodes.ASTORE;
521 default -> throw new InternalError("unknown type: " + type);
522 };
523 }
524 private void emitAstoreInsn(int index) {
525 emitStoreInsn(L_TYPE, index);
526 }
527
528 private byte arrayTypeCode(Wrapper elementType) {
529 return (byte) switch (elementType) {
530 case BOOLEAN -> Opcodes.T_BOOLEAN;
531 case BYTE -> Opcodes.T_BYTE;
532 case CHAR -> Opcodes.T_CHAR;
533 case SHORT -> Opcodes.T_SHORT;
534 case INT -> Opcodes.T_INT;
535 case LONG -> Opcodes.T_LONG;
536 case FLOAT -> Opcodes.T_FLOAT;
537 case DOUBLE -> Opcodes.T_DOUBLE;
538 case OBJECT -> 0; // in place of Opcodes.T_OBJECT
539 default -> throw new InternalError();
540 };
541 }
542
543 private int arrayInsnOpcode(byte tcode, int aaop) throws InternalError {
544 assert(aaop == Opcodes.AASTORE || aaop == Opcodes.AALOAD);
545 int xas = switch (tcode) {
546 case Opcodes.T_BOOLEAN -> Opcodes.BASTORE;
547 case Opcodes.T_BYTE -> Opcodes.BASTORE;
548 case Opcodes.T_CHAR -> Opcodes.CASTORE;
549 case Opcodes.T_SHORT -> Opcodes.SASTORE;
550 case Opcodes.T_INT -> Opcodes.IASTORE;
551 case Opcodes.T_LONG -> Opcodes.LASTORE;
552 case Opcodes.T_FLOAT -> Opcodes.FASTORE;
553 case Opcodes.T_DOUBLE -> Opcodes.DASTORE;
554 case 0 -> Opcodes.AASTORE;
555 default -> throw new InternalError();
556 };
557 return xas - Opcodes.AASTORE + aaop;
558 }
559
560 /**
561 * Emit a boxing call.
562 *
563 * @param wrapper primitive type class to box.
564 */
565 private void emitBoxing(Wrapper wrapper) {
566 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
567 String name = "valueOf";
568 String desc = "(" + wrapper.basicTypeChar() + ")L" + owner + ";";
569 mv.visitMethodInsn(Opcodes.INVOKESTATIC, owner, name, desc, false);
570 }
571
572 /**
573 * Emit an unboxing call (plus preceding checkcast).
574 *
575 * @param wrapper wrapper type class to unbox.
576 */
577 private void emitUnboxing(Wrapper wrapper) {
578 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
579 String name = wrapper.primitiveSimpleName() + "Value";
580 String desc = "()" + wrapper.basicTypeChar();
581 emitReferenceCast(wrapper.wrapperType(), null);
582 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, owner, name, desc, false);
583 }
584
585 /**
586 * Emit an implicit conversion for an argument which must be of the given pclass.
587 * This is usually a no-op, except when pclass is a subword type or a reference other than Object or an interface.
588 *
589 * @param ptype type of value present on stack
590 * @param pclass type of value required on stack
591 * @param arg compile-time representation of value on stack (Node, constant) or null if none
592 */
593 private void emitImplicitConversion(BasicType ptype, Class<?> pclass, Object arg) {
594 assert(basicType(pclass) == ptype); // boxing/unboxing handled by caller
595 if (pclass == ptype.basicTypeClass() && ptype != L_TYPE)
596 return; // nothing to do
597 switch (ptype) {
598 case L_TYPE:
599 if (VerifyType.isNullConversion(Object.class, pclass, false)) {
600 if (PROFILE_LEVEL > 0)
601 emitReferenceCast(Object.class, arg);
602 return;
603 }
604 emitReferenceCast(pclass, arg);
605 return;
606 case I_TYPE:
607 if (!VerifyType.isNullConversion(int.class, pclass, false))
608 emitPrimCast(ptype.basicTypeWrapper(), Wrapper.forPrimitiveType(pclass));
609 return;
610 }
611 throw newInternalError("bad implicit conversion: tc="+ptype+": "+pclass);
612 }
613
614 /** Update localClasses type map. Return true if the information is already present. */
615 private boolean assertStaticType(Class<?> cls, Name n) {
616 int local = n.index();
617 Class<?> aclass = localClasses[local];
618 if (aclass != null && (aclass == cls || cls.isAssignableFrom(aclass))) {
619 return true; // type info is already present
620 } else if (aclass == null || aclass.isAssignableFrom(cls)) {
621 localClasses[local] = cls; // type info can be improved
622 }
623 return false;
624 }
625
626 private void emitReferenceCast(Class<?> cls, Object arg) {
627 Name writeBack = null; // local to write back result
628 if (arg instanceof Name n) {
629 if (lambdaForm.useCount(n) > 1) {
630 // This guy gets used more than once.
631 writeBack = n;
632 if (assertStaticType(cls, n)) {
633 return; // this cast was already performed
634 }
635 }
636 }
637 if (isStaticallyNameable(cls)) {
638 String sig = getInternalName(cls);
639 mv.visitTypeInsn(Opcodes.CHECKCAST, sig);
640 } else {
641 mv.visitFieldInsn(Opcodes.GETSTATIC, className, classData(cls), "Ljava/lang/Class;");
642 mv.visitInsn(Opcodes.SWAP);
643 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, CLS, "cast", LL_SIG, false);
644 if (Object[].class.isAssignableFrom(cls))
645 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJARY);
646 else if (PROFILE_LEVEL > 0)
647 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJ);
648 }
649 if (writeBack != null) {
650 mv.visitInsn(Opcodes.DUP);
651 emitAstoreInsn(writeBack.index());
652 }
653 }
654
655 /**
656 * Emits an actual return instruction conforming to the given return type.
657 */
658 private void emitReturnInsn(BasicType type) {
659 int opcode = switch (type) {
660 case I_TYPE -> Opcodes.IRETURN;
661 case J_TYPE -> Opcodes.LRETURN;
662 case F_TYPE -> Opcodes.FRETURN;
663 case D_TYPE -> Opcodes.DRETURN;
664 case L_TYPE -> Opcodes.ARETURN;
665 case V_TYPE -> Opcodes.RETURN;
666 default -> throw new InternalError("unknown return type: " + type);
667 };
668 mv.visitInsn(opcode);
669 }
670
671 private String getInternalName(Class<?> c) {
672 if (c == Object.class) return OBJ;
673 else if (c == Object[].class) return OBJARY;
674 else if (c == Class.class) return CLS;
675 else if (c == MethodHandle.class) return MH;
676 assert(VerifyAccess.isTypeVisible(c, Object.class)) : c.getName();
677
678 if (c == lastClass) {
679 return lastInternalName;
680 }
681 lastClass = c;
682 return lastInternalName = c.getName().replace('.', '/');
683 }
684
685 private static MemberName resolveFrom(String name, MethodType type, Class<?> holder) {
686 assert(!UNSAFE.shouldBeInitialized(holder)) : holder + "not initialized";
687 MemberName member = new MemberName(holder, name, type, REF_invokeStatic);
688 MemberName resolvedMember = MemberName.getFactory().resolveOrNull(REF_invokeStatic, member, holder, LM_TRUSTED);
689 traceLambdaForm(name, type, holder, resolvedMember);
690 return resolvedMember;
691 }
692
693 private static MemberName lookupPregenerated(LambdaForm form, MethodType invokerType) {
694 if (form.customized != null) {
695 // No pre-generated version for customized LF
696 return null;
697 }
698 String name = form.kind.methodName;
699 switch (form.kind) {
700 case BOUND_REINVOKER: {
701 name = name + "_" + BoundMethodHandle.speciesDataFor(form).key();
702 return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class);
703 }
704 case DELEGATE: return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class);
705 case ZERO: // fall-through
706 case IDENTITY: {
707 name = name + "_" + form.returnType().basicTypeChar();
708 return resolveFrom(name, invokerType, LambdaForm.Holder.class);
709 }
710 case EXACT_INVOKER: // fall-through
711 case EXACT_LINKER: // fall-through
712 case LINK_TO_CALL_SITE: // fall-through
713 case LINK_TO_TARGET_METHOD: // fall-through
714 case GENERIC_INVOKER: // fall-through
715 case GENERIC_LINKER: return resolveFrom(name, invokerType, Invokers.Holder.class);
716 case GET_REFERENCE: // fall-through
717 case GET_BOOLEAN: // fall-through
718 case GET_BYTE: // fall-through
719 case GET_CHAR: // fall-through
720 case GET_SHORT: // fall-through
721 case GET_INT: // fall-through
722 case GET_LONG: // fall-through
723 case GET_FLOAT: // fall-through
724 case GET_DOUBLE: // fall-through
725 case PUT_REFERENCE: // fall-through
726 case PUT_BOOLEAN: // fall-through
727 case PUT_BYTE: // fall-through
728 case PUT_CHAR: // fall-through
729 case PUT_SHORT: // fall-through
730 case PUT_INT: // fall-through
731 case PUT_LONG: // fall-through
732 case PUT_FLOAT: // fall-through
733 case PUT_DOUBLE: // fall-through
734 case DIRECT_NEW_INVOKE_SPECIAL: // fall-through
735 case DIRECT_INVOKE_INTERFACE: // fall-through
736 case DIRECT_INVOKE_SPECIAL: // fall-through
737 case DIRECT_INVOKE_SPECIAL_IFC: // fall-through
738 case DIRECT_INVOKE_STATIC: // fall-through
739 case DIRECT_INVOKE_STATIC_INIT: // fall-through
740 case DIRECT_INVOKE_VIRTUAL: return resolveFrom(name, invokerType, DirectMethodHandle.Holder.class);
741 }
742 return null;
743 }
744
745 /**
746 * Generate customized bytecode for a given LambdaForm.
747 */
748 static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) {
749 MemberName pregenerated = lookupPregenerated(form, invokerType);
750 if (pregenerated != null) return pregenerated; // pre-generated bytecode
751
752 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("MH", form, invokerType);
753 return g.loadMethod(g.generateCustomizedCodeBytes());
754 }
755
756 /** Generates code to check that actual receiver and LambdaForm matches */
757 private boolean checkActualReceiver() {
758 // Expects MethodHandle on the stack and actual receiver MethodHandle in slot #0
759 mv.visitInsn(Opcodes.DUP);
760 mv.visitVarInsn(Opcodes.ALOAD, localsMap[0]);
761 mv.visitMethodInsn(Opcodes.INVOKESTATIC, MHI, "assertSame", LLV_SIG, false);
762 return true;
763 }
764
765 static String className(String cn) {
766 assert checkClassName(cn): "Class not found: " + cn;
767 return cn;
768 }
769
770 static boolean checkClassName(String cn) {
771 Type tp = Type.getType(cn);
772 // additional sanity so only valid "L;" descriptors work
773 if (tp.getSort() != Type.OBJECT) {
774 return false;
775 }
776 try {
777 Class<?> c = Class.forName(tp.getClassName(), false, null);
778 return true;
779 } catch (ClassNotFoundException e) {
780 return false;
781 }
782 }
783
784 static final String DONTINLINE_SIG = className("Ljdk/internal/vm/annotation/DontInline;");
785 static final String FORCEINLINE_SIG = className("Ljdk/internal/vm/annotation/ForceInline;");
786 static final String HIDDEN_SIG = className("Ljdk/internal/vm/annotation/Hidden;");
787 static final String INJECTEDPROFILE_SIG = className("Ljava/lang/invoke/InjectedProfile;");
788 static final String LF_COMPILED_SIG = className("Ljava/lang/invoke/LambdaForm$Compiled;");
789
790 /**
791 * Generate an invoker method for the passed {@link LambdaForm}.
792 */
793 private byte[] generateCustomizedCodeBytes() {
794 classFilePrologue();
795 addMethod();
796 clinit(cw, className, classData);
797 bogusMethod(lambdaForm);
798
799 final byte[] classFile = toByteArray();
800 maybeDump(classFile);
801 return classFile;
802 }
803
804 void setClassWriter(ClassWriter cw) {
805 this.cw = cw;
806 }
807
808 void addMethod() {
809 methodPrologue();
810
811 // Suppress this method in backtraces displayed to the user.
812 mv.visitAnnotation(HIDDEN_SIG, true);
813
814 // Mark this method as a compiled LambdaForm
815 mv.visitAnnotation(LF_COMPILED_SIG, true);
816
817 if (lambdaForm.forceInline) {
818 // Force inlining of this invoker method.
819 mv.visitAnnotation(FORCEINLINE_SIG, true);
820 } else {
821 mv.visitAnnotation(DONTINLINE_SIG, true);
822 }
823
824 classData(lambdaForm); // keep LambdaForm instance & its compiled form lifetime tightly coupled.
825
826 if (lambdaForm.customized != null) {
827 // Since LambdaForm is customized for a particular MethodHandle, it's safe to substitute
828 // receiver MethodHandle (at slot #0) with an embedded constant and use it instead.
829 // It enables more efficient code generation in some situations, since embedded constants
830 // are compile-time constants for JIT compiler.
831 mv.visitFieldInsn(Opcodes.GETSTATIC, className, classData(lambdaForm.customized), MH_SIG);
832 mv.visitTypeInsn(Opcodes.CHECKCAST, MH);
833 assert(checkActualReceiver()); // expects MethodHandle on top of the stack
834 mv.visitVarInsn(Opcodes.ASTORE, localsMap[0]);
835 }
836
837 // iterate over the form's names, generating bytecode instructions for each
838 // start iterating at the first name following the arguments
839 Name onStack = null;
840 for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) {
841 Name name = lambdaForm.names[i];
842
843 emitStoreResult(onStack);
844 onStack = name; // unless otherwise modified below
845 MethodHandleImpl.Intrinsic intr = name.function.intrinsicName();
846 switch (intr) {
847 case SELECT_ALTERNATIVE:
848 assert lambdaForm.isSelectAlternative(i);
849 if (PROFILE_GWT) {
850 assert(name.arguments[0] instanceof Name &&
851 ((Name)name.arguments[0]).refersTo(MethodHandleImpl.class, "profileBoolean"));
852 mv.visitAnnotation(INJECTEDPROFILE_SIG, true);
853 }
854 onStack = emitSelectAlternative(name, lambdaForm.names[i+1]);
855 i++; // skip MH.invokeBasic of the selectAlternative result
856 continue;
857 case GUARD_WITH_CATCH:
858 assert lambdaForm.isGuardWithCatch(i);
859 onStack = emitGuardWithCatch(i);
860 i += 2; // jump to the end of GWC idiom
861 continue;
862 case TRY_FINALLY:
863 assert lambdaForm.isTryFinally(i);
864 onStack = emitTryFinally(i);
865 i += 2; // jump to the end of the TF idiom
866 continue;
867 case TABLE_SWITCH:
868 assert lambdaForm.isTableSwitch(i);
869 int numCases = (Integer) name.function.intrinsicData();
870 onStack = emitTableSwitch(i, numCases);
871 i += 2; // jump to the end of the TS idiom
872 continue;
873 case LOOP:
874 assert lambdaForm.isLoop(i);
875 onStack = emitLoop(i);
876 i += 2; // jump to the end of the LOOP idiom
877 continue;
878 case ARRAY_LOAD:
879 emitArrayLoad(name);
880 continue;
881 case ARRAY_STORE:
882 emitArrayStore(name);
883 continue;
884 case ARRAY_LENGTH:
885 emitArrayLength(name);
886 continue;
887 case IDENTITY:
888 assert(name.arguments.length == 1);
889 emitPushArguments(name, 0);
890 continue;
891 case ZERO:
892 assert(name.arguments.length == 0);
893 emitConst(name.type.basicTypeWrapper().zero());
894 continue;
895 case NONE:
896 // no intrinsic associated
897 break;
898 default:
899 throw newInternalError("Unknown intrinsic: "+intr);
900 }
901
902 MemberName member = name.function.member();
903 if (isStaticallyInvocable(member)) {
904 emitStaticInvoke(member, name);
905 } else {
906 emitInvoke(name);
907 }
908 }
909
910 // return statement
911 emitReturn(onStack);
912
913 methodEpilogue();
914 }
915
916 /*
917 * @throws BytecodeGenerationException if something goes wrong when
918 * generating the byte code
919 */
920 private byte[] toByteArray() {
921 try {
922 return cw.toByteArray();
923 } catch (RuntimeException e) {
924 throw new BytecodeGenerationException(e);
925 }
926 }
927
928 /**
929 * The BytecodeGenerationException.
930 */
931 @SuppressWarnings("serial")
932 static final class BytecodeGenerationException extends RuntimeException {
933 BytecodeGenerationException(Exception cause) {
934 super(cause);
935 }
936 }
937
938 void emitArrayLoad(Name name) { emitArrayOp(name, Opcodes.AALOAD); }
939 void emitArrayStore(Name name) { emitArrayOp(name, Opcodes.AASTORE); }
940 void emitArrayLength(Name name) { emitArrayOp(name, Opcodes.ARRAYLENGTH); }
941
942 void emitArrayOp(Name name, int arrayOpcode) {
943 assert arrayOpcode == Opcodes.AALOAD || arrayOpcode == Opcodes.AASTORE || arrayOpcode == Opcodes.ARRAYLENGTH;
944 Class<?> elementType = name.function.methodType().parameterType(0).getComponentType();
945 assert elementType != null;
946 emitPushArguments(name, 0);
947 if (arrayOpcode != Opcodes.ARRAYLENGTH && elementType.isPrimitive()) {
948 Wrapper w = Wrapper.forPrimitiveType(elementType);
949 arrayOpcode = arrayInsnOpcode(arrayTypeCode(w), arrayOpcode);
950 }
951 mv.visitInsn(arrayOpcode);
952 }
953
954 /**
955 * Emit an invoke for the given name.
956 */
957 void emitInvoke(Name name) {
958 assert(!name.isLinkerMethodInvoke()); // should use the static path for these
959 if (true) {
960 // push receiver
961 MethodHandle target = name.function.resolvedHandle();
962 assert(target != null) : name.exprString();
963 mv.visitFieldInsn(Opcodes.GETSTATIC, className, classData(target), MH_SIG);
964 emitReferenceCast(MethodHandle.class, target);
965 } else {
966 // load receiver
967 emitAloadInsn(0);
968 emitReferenceCast(MethodHandle.class, null);
969 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", LF_SIG);
970 mv.visitFieldInsn(Opcodes.GETFIELD, LF, "names", LFN_SIG);
971 // TODO more to come
972 }
973
974 // push arguments
975 emitPushArguments(name, 0);
976
977 // invocation
978 MethodType type = name.function.methodType();
979 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
980 }
981
982 private static final Class<?>[] STATICALLY_INVOCABLE_PACKAGES = {
983 // Sample classes from each package we are willing to bind to statically:
984 java.lang.Object.class,
985 java.util.Arrays.class,
986 jdk.internal.misc.Unsafe.class
987 //MethodHandle.class already covered
988 };
989
990 static boolean isStaticallyInvocable(NamedFunction ... functions) {
991 for (NamedFunction nf : functions) {
992 if (!isStaticallyInvocable(nf.member())) {
993 return false;
994 }
995 }
996 return true;
997 }
998
999 static boolean isStaticallyInvocable(Name name) {
1000 return isStaticallyInvocable(name.function.member());
1001 }
1002
1003 static boolean isStaticallyInvocable(MemberName member) {
1004 if (member == null) return false;
1005 if (member.isObjectConstructorOrStaticInitMethod()) return false;
1006
1007 Class<?> cls = member.getDeclaringClass();
1008 // Fast-path non-private members declared by MethodHandles, which is a common
1009 // case
1010 if (MethodHandle.class.isAssignableFrom(cls) && !member.isPrivate()) {
1011 assert(isStaticallyInvocableType(member.getMethodOrFieldType()));
1012 return true;
1013 }
1014 if (cls.isArray() || cls.isPrimitive())
1015 return false; // FIXME
1016 if (cls.isAnonymousClass() || cls.isLocalClass())
1017 return false; // inner class of some sort
1018 if (cls.getClassLoader() != MethodHandle.class.getClassLoader())
1019 return false; // not on BCP
1020 if (cls.isHidden())
1021 return false;
1022 if (!isStaticallyInvocableType(member.getMethodOrFieldType()))
1023 return false;
1024 if (!member.isPrivate() && VerifyAccess.isSamePackage(MethodHandle.class, cls))
1025 return true; // in java.lang.invoke package
1026 if (member.isPublic() && isStaticallyNameable(cls))
1027 return true;
1028 return false;
1029 }
1030
1031 private static boolean isStaticallyInvocableType(MethodType mtype) {
1032 if (!isStaticallyNameable(mtype.returnType()))
1033 return false;
1034 for (Class<?> ptype : mtype.parameterArray())
1035 if (!isStaticallyNameable(ptype))
1036 return false;
1037 return true;
1038 }
1039
1040 static boolean isStaticallyNameable(Class<?> cls) {
1041 if (cls == Object.class)
1042 return true;
1043 if (MethodHandle.class.isAssignableFrom(cls)) {
1044 assert(!cls.isHidden());
1045 return true;
1046 }
1047 while (cls.isArray())
1048 cls = cls.getComponentType();
1049 if (cls.isPrimitive())
1050 return true; // int[].class, for example
1051 if (cls.isHidden())
1052 return false;
1053 // could use VerifyAccess.isClassAccessible but the following is a safe approximation
1054 if (cls.getClassLoader() != Object.class.getClassLoader())
1055 return false;
1056 if (VerifyAccess.isSamePackage(MethodHandle.class, cls))
1057 return true;
1058 if (!Modifier.isPublic(cls.getModifiers()))
1059 return false;
1060 for (Class<?> pkgcls : STATICALLY_INVOCABLE_PACKAGES) {
1061 if (VerifyAccess.isSamePackage(pkgcls, cls))
1062 return true;
1063 }
1064 return false;
1065 }
1066
1067 void emitStaticInvoke(Name name) {
1068 emitStaticInvoke(name.function.member(), name);
1069 }
1070
1071 /**
1072 * Emit an invoke for the given name, using the MemberName directly.
1073 */
1074 void emitStaticInvoke(MemberName member, Name name) {
1075 assert(member.equals(name.function.member()));
1076 Class<?> defc = member.getDeclaringClass();
1077 String cname = getInternalName(defc);
1078 String mname = member.getName();
1079 String mtype;
1080 byte refKind = member.getReferenceKind();
1081 if (refKind == REF_invokeSpecial) {
1082 // in order to pass the verifier, we need to convert this to invokevirtual in all cases
1083 assert(member.canBeStaticallyBound()) : member;
1084 refKind = REF_invokeVirtual;
1085 }
1086
1087 assert(!(member.getDeclaringClass().isInterface() && refKind == REF_invokeVirtual));
1088
1089 // push arguments
1090 emitPushArguments(name, 0);
1091
1092 // invocation
1093 if (member.isMethod()) {
1094 mtype = member.getMethodType().toMethodDescriptorString();
1095 mv.visitMethodInsn(refKindOpcode(refKind), cname, mname, mtype,
1096 member.getDeclaringClass().isInterface());
1097 } else {
1098 mtype = MethodType.toFieldDescriptorString(member.getFieldType());
1099 mv.visitFieldInsn(refKindOpcode(refKind), cname, mname, mtype);
1100 }
1101 // Issue a type assertion for the result, so we can avoid casts later.
1102 if (name.type == L_TYPE) {
1103 Class<?> rtype = member.getInvocationType().returnType();
1104 assert(!rtype.isPrimitive());
1105 if (rtype != Object.class && !rtype.isInterface()) {
1106 assertStaticType(rtype, name);
1107 }
1108 }
1109 }
1110
1111 int refKindOpcode(byte refKind) {
1112 switch (refKind) {
1113 case REF_invokeVirtual: return Opcodes.INVOKEVIRTUAL;
1114 case REF_invokeStatic: return Opcodes.INVOKESTATIC;
1115 case REF_invokeSpecial: return Opcodes.INVOKESPECIAL;
1116 case REF_invokeInterface: return Opcodes.INVOKEINTERFACE;
1117 case REF_getField: return Opcodes.GETFIELD;
1118 case REF_putField: return Opcodes.PUTFIELD;
1119 case REF_getStatic: return Opcodes.GETSTATIC;
1120 case REF_putStatic: return Opcodes.PUTSTATIC;
1121 }
1122 throw new InternalError("refKind="+refKind);
1123 }
1124
1125 /**
1126 * Emit bytecode for the selectAlternative idiom.
1127 *
1128 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithTest):
1129 * <blockquote><pre>{@code
1130 * Lambda(a0:L,a1:I)=>{
1131 * t2:I=foo.test(a1:I);
1132 * t3:L=MethodHandleImpl.selectAlternative(t2:I,(MethodHandle(int)int),(MethodHandle(int)int));
1133 * t4:I=MethodHandle.invokeBasic(t3:L,a1:I);t4:I}
1134 * }</pre></blockquote>
1135 */
1136 private Name emitSelectAlternative(Name selectAlternativeName, Name invokeBasicName) {
1137 assert isStaticallyInvocable(invokeBasicName);
1138
1139 Name receiver = (Name) invokeBasicName.arguments[0];
1140
1141 Label L_fallback = new Label();
1142 Label L_done = new Label();
1143
1144 // load test result
1145 emitPushArgument(selectAlternativeName, 0);
1146
1147 // if_icmpne L_fallback
1148 mv.visitJumpInsn(Opcodes.IFEQ, L_fallback);
1149
1150 // invoke selectAlternativeName.arguments[1]
1151 Class<?>[] preForkClasses = localClasses.clone();
1152 emitPushArgument(selectAlternativeName, 1); // get 2nd argument of selectAlternative
1153 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
1154 emitStaticInvoke(invokeBasicName);
1155
1156 // goto L_done
1157 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1158
1159 // L_fallback:
1160 mv.visitLabel(L_fallback);
1161
1162 // invoke selectAlternativeName.arguments[2]
1163 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
1164 emitPushArgument(selectAlternativeName, 2); // get 3rd argument of selectAlternative
1165 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
1166 emitStaticInvoke(invokeBasicName);
1167
1168 // L_done:
1169 mv.visitLabel(L_done);
1170 // for now do not bother to merge typestate; just reset to the dominator state
1171 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
1172
1173 return invokeBasicName; // return what's on stack
1174 }
1175
1176 /**
1177 * Emit bytecode for the guardWithCatch idiom.
1178 *
1179 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithCatch):
1180 * <blockquote><pre>{@code
1181 * guardWithCatch=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{
1182 * t8:L=MethodHandle.invokeBasic(a4:L,a6:L,a7:L);
1183 * t9:L=MethodHandleImpl.guardWithCatch(a1:L,a2:L,a3:L,t8:L);
1184 * t10:I=MethodHandle.invokeBasic(a5:L,t9:L);t10:I}
1185 * }</pre></blockquote>
1186 *
1187 * It is compiled into bytecode equivalent of the following code:
1188 * <blockquote><pre>{@code
1189 * try {
1190 * return a1.invokeBasic(a6, a7);
1191 * } catch (Throwable e) {
1192 * if (!a2.isInstance(e)) throw e;
1193 * return a3.invokeBasic(ex, a6, a7);
1194 * }}</pre></blockquote>
1195 */
1196 private Name emitGuardWithCatch(int pos) {
1197 Name args = lambdaForm.names[pos];
1198 Name invoker = lambdaForm.names[pos+1];
1199 Name result = lambdaForm.names[pos+2];
1200
1201 Label L_startBlock = new Label();
1202 Label L_endBlock = new Label();
1203 Label L_handler = new Label();
1204 Label L_done = new Label();
1205
1206 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1207 MethodType type = args.function.resolvedHandle().type()
1208 .dropParameterTypes(0,1)
1209 .changeReturnType(returnType);
1210
1211 mv.visitTryCatchBlock(L_startBlock, L_endBlock, L_handler, "java/lang/Throwable");
1212
1213 // Normal case
1214 mv.visitLabel(L_startBlock);
1215 // load target
1216 emitPushArgument(invoker, 0);
1217 emitPushArguments(args, 1); // skip 1st argument: method handle
1218 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
1219 mv.visitLabel(L_endBlock);
1220 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1221
1222 // Exceptional case
1223 mv.visitLabel(L_handler);
1224
1225 // Check exception's type
1226 mv.visitInsn(Opcodes.DUP);
1227 // load exception class
1228 emitPushArgument(invoker, 1);
1229 mv.visitInsn(Opcodes.SWAP);
1230 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Class", "isInstance", "(Ljava/lang/Object;)Z", false);
1231 Label L_rethrow = new Label();
1232 mv.visitJumpInsn(Opcodes.IFEQ, L_rethrow);
1233
1234 // Invoke catcher
1235 // load catcher
1236 emitPushArgument(invoker, 2);
1237 mv.visitInsn(Opcodes.SWAP);
1238 emitPushArguments(args, 1); // skip 1st argument: method handle
1239 MethodType catcherType = type.insertParameterTypes(0, Throwable.class);
1240 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", catcherType.basicType().toMethodDescriptorString(), false);
1241 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1242
1243 mv.visitLabel(L_rethrow);
1244 mv.visitInsn(Opcodes.ATHROW);
1245
1246 mv.visitLabel(L_done);
1247
1248 return result;
1249 }
1250
1251 /**
1252 * Emit bytecode for the tryFinally idiom.
1253 * <p>
1254 * The pattern looks like (Cf. MethodHandleImpl.makeTryFinally):
1255 * <blockquote><pre>{@code
1256 * // a0: BMH
1257 * // a1: target, a2: cleanup
1258 * // a3: box, a4: unbox
1259 * // a5 (and following): arguments
1260 * tryFinally=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L)=>{
1261 * t6:L=MethodHandle.invokeBasic(a3:L,a5:L); // box the arguments into an Object[]
1262 * t7:L=MethodHandleImpl.tryFinally(a1:L,a2:L,t6:L); // call the tryFinally executor
1263 * t8:L=MethodHandle.invokeBasic(a4:L,t7:L);t8:L} // unbox the result; return the result
1264 * }</pre></blockquote>
1265 * <p>
1266 * It is compiled into bytecode equivalent to the following code:
1267 * <blockquote><pre>{@code
1268 * Throwable t;
1269 * Object r;
1270 * try {
1271 * r = a1.invokeBasic(a5);
1272 * } catch (Throwable thrown) {
1273 * t = thrown;
1274 * throw t;
1275 * } finally {
1276 * r = a2.invokeBasic(t, r, a5);
1277 * }
1278 * return r;
1279 * }</pre></blockquote>
1280 * <p>
1281 * Specifically, the bytecode will have the following form (the stack effects are given for the beginnings of
1282 * blocks, and for the situations after executing the given instruction - the code will have a slightly different
1283 * shape if the return type is {@code void}):
1284 * <blockquote><pre>{@code
1285 * TRY: (--)
1286 * load target (-- target)
1287 * load args (-- args... target)
1288 * INVOKEVIRTUAL MethodHandle.invokeBasic (depends)
1289 * FINALLY_NORMAL: (-- r_2nd* r)
1290 * store returned value (--)
1291 * load cleanup (-- cleanup)
1292 * ACONST_NULL (-- t cleanup)
1293 * load returned value (-- r_2nd* r t cleanup)
1294 * load args (-- args... r_2nd* r t cleanup)
1295 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r_2nd* r)
1296 * GOTO DONE
1297 * CATCH: (-- t)
1298 * DUP (-- t t)
1299 * FINALLY_EXCEPTIONAL: (-- t t)
1300 * load cleanup (-- cleanup t t)
1301 * SWAP (-- t cleanup t)
1302 * load default for r (-- r_2nd* r t cleanup t)
1303 * load args (-- args... r_2nd* r t cleanup t)
1304 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r_2nd* r t)
1305 * POP/POP2* (-- t)
1306 * ATHROW
1307 * DONE: (-- r)
1308 * }</pre></blockquote>
1309 * * = depends on whether the return type takes up 2 stack slots.
1310 */
1311 private Name emitTryFinally(int pos) {
1312 Name args = lambdaForm.names[pos];
1313 Name invoker = lambdaForm.names[pos+1];
1314 Name result = lambdaForm.names[pos+2];
1315
1316 Label lFrom = new Label();
1317 Label lTo = new Label();
1318 Label lCatch = new Label();
1319 Label lDone = new Label();
1320
1321 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1322 BasicType basicReturnType = BasicType.basicType(returnType);
1323 boolean isNonVoid = returnType != void.class;
1324
1325 MethodType type = args.function.resolvedHandle().type()
1326 .dropParameterTypes(0,1)
1327 .changeReturnType(returnType);
1328 MethodType cleanupType = type.insertParameterTypes(0, Throwable.class);
1329 if (isNonVoid) {
1330 cleanupType = cleanupType.insertParameterTypes(1, returnType);
1331 }
1332 String cleanupDesc = cleanupType.basicType().toMethodDescriptorString();
1333
1334 // exception handler table
1335 mv.visitTryCatchBlock(lFrom, lTo, lCatch, "java/lang/Throwable");
1336
1337 // TRY:
1338 mv.visitLabel(lFrom);
1339 emitPushArgument(invoker, 0); // load target
1340 emitPushArguments(args, 1); // load args (skip 0: method handle)
1341 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
1342 mv.visitLabel(lTo);
1343
1344 // FINALLY_NORMAL:
1345 int index = extendLocalsMap(new Class<?>[]{ returnType });
1346 if (isNonVoid) {
1347 emitStoreInsn(basicReturnType, index);
1348 }
1349 emitPushArgument(invoker, 1); // load cleanup
1350 mv.visitInsn(Opcodes.ACONST_NULL);
1351 if (isNonVoid) {
1352 emitLoadInsn(basicReturnType, index);
1353 }
1354 emitPushArguments(args, 1); // load args (skip 0: method handle)
1355 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", cleanupDesc, false);
1356 mv.visitJumpInsn(Opcodes.GOTO, lDone);
1357
1358 // CATCH:
1359 mv.visitLabel(lCatch);
1360 mv.visitInsn(Opcodes.DUP);
1361
1362 // FINALLY_EXCEPTIONAL:
1363 emitPushArgument(invoker, 1); // load cleanup
1364 mv.visitInsn(Opcodes.SWAP);
1365 if (isNonVoid) {
1366 emitZero(BasicType.basicType(returnType)); // load default for result
1367 }
1368 emitPushArguments(args, 1); // load args (skip 0: method handle)
1369 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", cleanupDesc, false);
1370 if (isNonVoid) {
1371 emitPopInsn(basicReturnType);
1372 }
1373 mv.visitInsn(Opcodes.ATHROW);
1374
1375 // DONE:
1376 mv.visitLabel(lDone);
1377
1378 return result;
1379 }
1380
1381 private void emitPopInsn(BasicType type) {
1382 mv.visitInsn(popInsnOpcode(type));
1383 }
1384
1385 private static int popInsnOpcode(BasicType type) {
1386 return switch (type) {
1387 case I_TYPE, F_TYPE, L_TYPE -> Opcodes.POP;
1388 case J_TYPE, D_TYPE -> Opcodes.POP2;
1389 default -> throw new InternalError("unknown type: " + type);
1390 };
1391 }
1392
1393 private Name emitTableSwitch(int pos, int numCases) {
1394 Name args = lambdaForm.names[pos];
1395 Name invoker = lambdaForm.names[pos + 1];
1396 Name result = lambdaForm.names[pos + 2];
1397
1398 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1399 MethodType caseType = args.function.resolvedHandle().type()
1400 .dropParameterTypes(0, 1) // drop collector
1401 .changeReturnType(returnType);
1402 String caseDescriptor = caseType.basicType().toMethodDescriptorString();
1403
1404 emitPushArgument(invoker, 2); // push cases
1405 mv.visitFieldInsn(Opcodes.GETFIELD, "java/lang/invoke/MethodHandleImpl$CasesHolder", "cases",
1406 "[Ljava/lang/invoke/MethodHandle;");
1407 int casesLocal = extendLocalsMap(new Class<?>[] { MethodHandle[].class });
1408 emitStoreInsn(L_TYPE, casesLocal);
1409
1410 Label endLabel = new Label();
1411 Label defaultLabel = new Label();
1412 Label[] caseLabels = new Label[numCases];
1413 for (int i = 0; i < caseLabels.length; i++) {
1414 caseLabels[i] = new Label();
1415 }
1416
1417 emitPushArgument(invoker, 0); // push switch input
1418 mv.visitTableSwitchInsn(0, numCases - 1, defaultLabel, caseLabels);
1419
1420 mv.visitLabel(defaultLabel);
1421 emitPushArgument(invoker, 1); // push default handle
1422 emitPushArguments(args, 1); // again, skip collector
1423 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", caseDescriptor, false);
1424 mv.visitJumpInsn(Opcodes.GOTO, endLabel);
1425
1426 for (int i = 0; i < numCases; i++) {
1427 mv.visitLabel(caseLabels[i]);
1428 // Load the particular case:
1429 emitLoadInsn(L_TYPE, casesLocal);
1430 emitIconstInsn(i);
1431 mv.visitInsn(Opcodes.AALOAD);
1432
1433 // invoke it:
1434 emitPushArguments(args, 1); // again, skip collector
1435 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", caseDescriptor, false);
1436
1437 mv.visitJumpInsn(Opcodes.GOTO, endLabel);
1438 }
1439
1440 mv.visitLabel(endLabel);
1441
1442 return result;
1443 }
1444
1445 /**
1446 * Emit bytecode for the loop idiom.
1447 * <p>
1448 * The pattern looks like (Cf. MethodHandleImpl.loop):
1449 * <blockquote><pre>{@code
1450 * // a0: BMH
1451 * // a1: LoopClauses (containing an array of arrays: inits, steps, preds, finis)
1452 * // a2: box, a3: unbox
1453 * // a4 (and following): arguments
1454 * loop=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L)=>{
1455 * t5:L=MethodHandle.invokeBasic(a2:L,a4:L); // box the arguments into an Object[]
1456 * t6:L=MethodHandleImpl.loop(bt:L,a1:L,t5:L); // call the loop executor (with supplied types in bt)
1457 * t7:L=MethodHandle.invokeBasic(a3:L,t6:L);t7:L} // unbox the result; return the result
1458 * }</pre></blockquote>
1459 * <p>
1460 * It is compiled into bytecode equivalent to the code seen in {@link MethodHandleImpl#loop(BasicType[],
1461 * MethodHandleImpl.LoopClauses, Object...)}, with the difference that no arrays
1462 * will be used for local state storage. Instead, the local state will be mapped to actual stack slots.
1463 * <p>
1464 * Bytecode generation applies an unrolling scheme to enable better bytecode generation regarding local state type
1465 * handling. The generated bytecode will have the following form ({@code void} types are ignored for convenience).
1466 * Assume there are {@code C} clauses in the loop.
1467 * <blockquote><pre>{@code
1468 * PREINIT: ALOAD_1
1469 * CHECKCAST LoopClauses
1470 * GETFIELD LoopClauses.clauses
1471 * ASTORE clauseDataIndex // place the clauses 2-dimensional array on the stack
1472 * INIT: (INIT_SEQ for clause 1)
1473 * ...
1474 * (INIT_SEQ for clause C)
1475 * LOOP: (LOOP_SEQ for clause 1)
1476 * ...
1477 * (LOOP_SEQ for clause C)
1478 * GOTO LOOP
1479 * DONE: ...
1480 * }</pre></blockquote>
1481 * <p>
1482 * The {@code INIT_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has
1483 * the following shape. Assume slot {@code vx} is used to hold the state for clause {@code x}.
1484 * <blockquote><pre>{@code
1485 * INIT_SEQ_x: ALOAD clauseDataIndex
1486 * ICONST_0
1487 * AALOAD // load the inits array
1488 * ICONST x
1489 * AALOAD // load the init handle for clause x
1490 * load args
1491 * INVOKEVIRTUAL MethodHandle.invokeBasic
1492 * store vx
1493 * }</pre></blockquote>
1494 * <p>
1495 * The {@code LOOP_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has
1496 * the following shape. Again, assume slot {@code vx} is used to hold the state for clause {@code x}.
1497 * <blockquote><pre>{@code
1498 * LOOP_SEQ_x: ALOAD clauseDataIndex
1499 * ICONST_1
1500 * AALOAD // load the steps array
1501 * ICONST x
1502 * AALOAD // load the step handle for clause x
1503 * load locals
1504 * load args
1505 * INVOKEVIRTUAL MethodHandle.invokeBasic
1506 * store vx
1507 * ALOAD clauseDataIndex
1508 * ICONST_2
1509 * AALOAD // load the preds array
1510 * ICONST x
1511 * AALOAD // load the pred handle for clause x
1512 * load locals
1513 * load args
1514 * INVOKEVIRTUAL MethodHandle.invokeBasic
1515 * IFNE LOOP_SEQ_x+1 // predicate returned false -> jump to next clause
1516 * ALOAD clauseDataIndex
1517 * ICONST_3
1518 * AALOAD // load the finis array
1519 * ICONST x
1520 * AALOAD // load the fini handle for clause x
1521 * load locals
1522 * load args
1523 * INVOKEVIRTUAL MethodHandle.invokeBasic
1524 * GOTO DONE // jump beyond end of clauses to return from loop
1525 * }</pre></blockquote>
1526 */
1527 private Name emitLoop(int pos) {
1528 Name args = lambdaForm.names[pos];
1529 Name invoker = lambdaForm.names[pos+1];
1530 Name result = lambdaForm.names[pos+2];
1531
1532 // extract clause and loop-local state types
1533 // find the type info in the loop invocation
1534 BasicType[] loopClauseTypes = (BasicType[]) invoker.arguments[0];
1535 Class<?>[] loopLocalStateTypes = Stream.of(loopClauseTypes).
1536 filter(bt -> bt != BasicType.V_TYPE).map(BasicType::basicTypeClass).toArray(Class<?>[]::new);
1537 Class<?>[] localTypes = new Class<?>[loopLocalStateTypes.length + 1];
1538 localTypes[0] = MethodHandleImpl.LoopClauses.class;
1539 System.arraycopy(loopLocalStateTypes, 0, localTypes, 1, loopLocalStateTypes.length);
1540
1541 final int clauseDataIndex = extendLocalsMap(localTypes);
1542 final int firstLoopStateIndex = clauseDataIndex + 1;
1543
1544 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1545 MethodType loopType = args.function.resolvedHandle().type()
1546 .dropParameterTypes(0,1)
1547 .changeReturnType(returnType);
1548 MethodType loopHandleType = loopType.insertParameterTypes(0, loopLocalStateTypes);
1549 MethodType predType = loopHandleType.changeReturnType(boolean.class);
1550 MethodType finiType = loopHandleType;
1551
1552 final int nClauses = loopClauseTypes.length;
1553
1554 // indices to invoker arguments to load method handle arrays
1555 final int inits = 1;
1556 final int steps = 2;
1557 final int preds = 3;
1558 final int finis = 4;
1559
1560 Label lLoop = new Label();
1561 Label lDone = new Label();
1562 Label lNext;
1563
1564 // PREINIT:
1565 emitPushArgument(MethodHandleImpl.LoopClauses.class, invoker.arguments[1]);
1566 mv.visitFieldInsn(Opcodes.GETFIELD, LOOP_CLAUSES, "clauses", MHARY2);
1567 emitAstoreInsn(clauseDataIndex);
1568
1569 // INIT:
1570 for (int c = 0, state = 0; c < nClauses; ++c) {
1571 MethodType cInitType = loopType.changeReturnType(loopClauseTypes[c].basicTypeClass());
1572 emitLoopHandleInvoke(invoker, inits, c, args, false, cInitType, loopLocalStateTypes, clauseDataIndex,
1573 firstLoopStateIndex);
1574 if (cInitType.returnType() != void.class) {
1575 emitStoreInsn(BasicType.basicType(cInitType.returnType()), firstLoopStateIndex + state);
1576 ++state;
1577 }
1578 }
1579
1580 // LOOP:
1581 mv.visitLabel(lLoop);
1582
1583 for (int c = 0, state = 0; c < nClauses; ++c) {
1584 lNext = new Label();
1585
1586 MethodType stepType = loopHandleType.changeReturnType(loopClauseTypes[c].basicTypeClass());
1587 boolean isVoid = stepType.returnType() == void.class;
1588
1589 // invoke loop step
1590 emitLoopHandleInvoke(invoker, steps, c, args, true, stepType, loopLocalStateTypes, clauseDataIndex,
1591 firstLoopStateIndex);
1592 if (!isVoid) {
1593 emitStoreInsn(BasicType.basicType(stepType.returnType()), firstLoopStateIndex + state);
1594 ++state;
1595 }
1596
1597 // invoke loop predicate
1598 emitLoopHandleInvoke(invoker, preds, c, args, true, predType, loopLocalStateTypes, clauseDataIndex,
1599 firstLoopStateIndex);
1600 mv.visitJumpInsn(Opcodes.IFNE, lNext);
1601
1602 // invoke fini
1603 emitLoopHandleInvoke(invoker, finis, c, args, true, finiType, loopLocalStateTypes, clauseDataIndex,
1604 firstLoopStateIndex);
1605 mv.visitJumpInsn(Opcodes.GOTO, lDone);
1606
1607 // this is the beginning of the next loop clause
1608 mv.visitLabel(lNext);
1609 }
1610
1611 mv.visitJumpInsn(Opcodes.GOTO, lLoop);
1612
1613 // DONE:
1614 mv.visitLabel(lDone);
1615
1616 return result;
1617 }
1618
1619 private int extendLocalsMap(Class<?>[] types) {
1620 int firstSlot = localsMap.length - 1;
1621 localsMap = Arrays.copyOf(localsMap, localsMap.length + types.length);
1622 localClasses = Arrays.copyOf(localClasses, localClasses.length + types.length);
1623 System.arraycopy(types, 0, localClasses, firstSlot, types.length);
1624 int index = localsMap[firstSlot - 1] + 1;
1625 int lastSlots = 0;
1626 for (int i = 0; i < types.length; ++i) {
1627 localsMap[firstSlot + i] = index;
1628 lastSlots = BasicType.basicType(localClasses[firstSlot + i]).basicTypeSlots();
1629 index += lastSlots;
1630 }
1631 localsMap[localsMap.length - 1] = index - lastSlots;
1632 return firstSlot;
1633 }
1634
1635 private void emitLoopHandleInvoke(Name holder, int handles, int clause, Name args, boolean pushLocalState,
1636 MethodType type, Class<?>[] loopLocalStateTypes, int clauseDataSlot,
1637 int firstLoopStateSlot) {
1638 // load handle for clause
1639 emitPushClauseArray(clauseDataSlot, handles);
1640 emitIconstInsn(clause);
1641 mv.visitInsn(Opcodes.AALOAD);
1642 // load loop state (preceding the other arguments)
1643 if (pushLocalState) {
1644 for (int s = 0; s < loopLocalStateTypes.length; ++s) {
1645 emitLoadInsn(BasicType.basicType(loopLocalStateTypes[s]), firstLoopStateSlot + s);
1646 }
1647 }
1648 // load loop args (skip 0: method handle)
1649 emitPushArguments(args, 1);
1650 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.toMethodDescriptorString(), false);
1651 }
1652
1653 private void emitPushClauseArray(int clauseDataSlot, int which) {
1654 emitAloadInsn(clauseDataSlot);
1655 emitIconstInsn(which - 1);
1656 mv.visitInsn(Opcodes.AALOAD);
1657 }
1658
1659 private void emitZero(BasicType type) {
1660 mv.visitInsn(switch (type) {
1661 case I_TYPE -> Opcodes.ICONST_0;
1662 case J_TYPE -> Opcodes.LCONST_0;
1663 case F_TYPE -> Opcodes.FCONST_0;
1664 case D_TYPE -> Opcodes.DCONST_0;
1665 case L_TYPE -> Opcodes.ACONST_NULL;
1666 default -> throw new InternalError("unknown type: " + type);
1667 });
1668 }
1669
1670 private void emitPushArguments(Name args, int start) {
1671 MethodType type = args.function.methodType();
1672 for (int i = start; i < args.arguments.length; i++) {
1673 emitPushArgument(type.parameterType(i), args.arguments[i]);
1674 }
1675 }
1676
1677 private void emitPushArgument(Name name, int paramIndex) {
1678 Object arg = name.arguments[paramIndex];
1679 Class<?> ptype = name.function.methodType().parameterType(paramIndex);
1680 emitPushArgument(ptype, arg);
1681 }
1682
1683 private void emitPushArgument(Class<?> ptype, Object arg) {
1684 BasicType bptype = basicType(ptype);
1685 if (arg instanceof Name n) {
1686 emitLoadInsn(n.type, n.index());
1687 emitImplicitConversion(n.type, ptype, n);
1688 } else if (arg == null && bptype == L_TYPE) {
1689 mv.visitInsn(Opcodes.ACONST_NULL);
1690 } else if (arg instanceof String && bptype == L_TYPE) {
1691 mv.visitLdcInsn(arg);
1692 } else {
1693 if (Wrapper.isWrapperType(arg.getClass()) && bptype != L_TYPE) {
1694 emitConst(arg);
1695 } else {
1696 mv.visitFieldInsn(Opcodes.GETSTATIC, className, classData(arg), "Ljava/lang/Object;");
1697 emitImplicitConversion(L_TYPE, ptype, arg);
1698 }
1699 }
1700 }
1701
1702 /**
1703 * Store the name to its local, if necessary.
1704 */
1705 private void emitStoreResult(Name name) {
1706 if (name != null && name.type != V_TYPE) {
1707 // non-void: actually assign
1708 emitStoreInsn(name.type, name.index());
1709 }
1710 }
1711
1712 /**
1713 * Emits a return statement from a LF invoker. If required, the result type is cast to the correct return type.
1714 */
1715 private void emitReturn(Name onStack) {
1716 // return statement
1717 Class<?> rclass = invokerType.returnType();
1718 BasicType rtype = lambdaForm.returnType();
1719 assert(rtype == basicType(rclass)); // must agree
1720 if (rtype == V_TYPE) {
1721 // void
1722 mv.visitInsn(Opcodes.RETURN);
1723 // it doesn't matter what rclass is; the JVM will discard any value
1724 } else {
1725 LambdaForm.Name rn = lambdaForm.names[lambdaForm.result];
1726
1727 // put return value on the stack if it is not already there
1728 if (rn != onStack) {
1729 emitLoadInsn(rtype, lambdaForm.result);
1730 }
1731
1732 emitImplicitConversion(rtype, rclass, rn);
1733
1734 // generate actual return statement
1735 emitReturnInsn(rtype);
1736 }
1737 }
1738
1739 /**
1740 * Emit a type conversion bytecode casting from "from" to "to".
1741 */
1742 private void emitPrimCast(Wrapper from, Wrapper to) {
1743 // Here's how.
1744 // - indicates forbidden
1745 // <-> indicates implicit
1746 // to ----> boolean byte short char int long float double
1747 // from boolean <-> - - - - - - -
1748 // byte - <-> i2s i2c <-> i2l i2f i2d
1749 // short - i2b <-> i2c <-> i2l i2f i2d
1750 // char - i2b i2s <-> <-> i2l i2f i2d
1751 // int - i2b i2s i2c <-> i2l i2f i2d
1752 // long - l2i,i2b l2i,i2s l2i,i2c l2i <-> l2f l2d
1753 // float - f2i,i2b f2i,i2s f2i,i2c f2i f2l <-> f2d
1754 // double - d2i,i2b d2i,i2s d2i,i2c d2i d2l d2f <->
1755 if (from == to) {
1756 // no cast required, should be dead code anyway
1757 return;
1758 }
1759 if (from.isSubwordOrInt()) {
1760 // cast from {byte,short,char,int} to anything
1761 emitI2X(to);
1762 } else {
1763 // cast from {long,float,double} to anything
1764 if (to.isSubwordOrInt()) {
1765 // cast to {byte,short,char,int}
1766 emitX2I(from);
1767 if (to.bitWidth() < 32) {
1768 // targets other than int require another conversion
1769 emitI2X(to);
1770 }
1771 } else {
1772 // cast to {long,float,double} - this is verbose
1773 boolean error = false;
1774 switch (from) {
1775 case LONG -> {
1776 switch (to) {
1777 case FLOAT -> mv.visitInsn(Opcodes.L2F);
1778 case DOUBLE -> mv.visitInsn(Opcodes.L2D);
1779 default -> error = true;
1780 }
1781 }
1782 case FLOAT -> {
1783 switch (to) {
1784 case LONG -> mv.visitInsn(Opcodes.F2L);
1785 case DOUBLE -> mv.visitInsn(Opcodes.F2D);
1786 default -> error = true;
1787 }
1788 }
1789 case DOUBLE -> {
1790 switch (to) {
1791 case LONG -> mv.visitInsn(Opcodes.D2L);
1792 case FLOAT -> mv.visitInsn(Opcodes.D2F);
1793 default -> error = true;
1794 }
1795 }
1796 default -> error = true;
1797 }
1798 if (error) {
1799 throw new IllegalStateException("unhandled prim cast: " + from + "2" + to);
1800 }
1801 }
1802 }
1803 }
1804
1805 private void emitI2X(Wrapper type) {
1806 switch (type) {
1807 case BYTE: mv.visitInsn(Opcodes.I2B); break;
1808 case SHORT: mv.visitInsn(Opcodes.I2S); break;
1809 case CHAR: mv.visitInsn(Opcodes.I2C); break;
1810 case INT: /* naught */ break;
1811 case LONG: mv.visitInsn(Opcodes.I2L); break;
1812 case FLOAT: mv.visitInsn(Opcodes.I2F); break;
1813 case DOUBLE: mv.visitInsn(Opcodes.I2D); break;
1814 case BOOLEAN:
1815 // For compatibility with ValueConversions and explicitCastArguments:
1816 mv.visitInsn(Opcodes.ICONST_1);
1817 mv.visitInsn(Opcodes.IAND);
1818 break;
1819 default: throw new InternalError("unknown type: " + type);
1820 }
1821 }
1822
1823 private void emitX2I(Wrapper type) {
1824 switch (type) {
1825 case LONG -> mv.visitInsn(Opcodes.L2I);
1826 case FLOAT -> mv.visitInsn(Opcodes.F2I);
1827 case DOUBLE -> mv.visitInsn(Opcodes.D2I);
1828 default -> throw new InternalError("unknown type: " + type);
1829 }
1830 }
1831
1832 /**
1833 * Generate bytecode for a LambdaForm.vmentry which calls interpretWithArguments.
1834 */
1835 static MemberName generateLambdaFormInterpreterEntryPoint(MethodType mt) {
1836 assert(isValidSignature(basicTypeSignature(mt)));
1837 String name = "interpret_"+basicTypeChar(mt.returnType());
1838 MethodType type = mt; // includes leading argument
1839 type = type.changeParameterType(0, MethodHandle.class);
1840 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("LFI", name, type);
1841 return g.loadMethod(g.generateLambdaFormInterpreterEntryPointBytes());
1842 }
1843
1844 private byte[] generateLambdaFormInterpreterEntryPointBytes() {
1845 classFilePrologue();
1846 methodPrologue();
1847
1848 // Suppress this method in backtraces displayed to the user.
1849 mv.visitAnnotation(HIDDEN_SIG, true);
1850
1851 // Don't inline the interpreter entry.
1852 mv.visitAnnotation(DONTINLINE_SIG, true);
1853
1854 // create parameter array
1855 emitIconstInsn(invokerType.parameterCount());
1856 mv.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object");
1857
1858 // fill parameter array
1859 for (int i = 0; i < invokerType.parameterCount(); i++) {
1860 Class<?> ptype = invokerType.parameterType(i);
1861 mv.visitInsn(Opcodes.DUP);
1862 emitIconstInsn(i);
1863 emitLoadInsn(basicType(ptype), i);
1864 // box if primitive type
1865 if (ptype.isPrimitive()) {
1866 emitBoxing(Wrapper.forPrimitiveType(ptype));
1867 }
1868 mv.visitInsn(Opcodes.AASTORE);
1869 }
1870 // invoke
1871 emitAloadInsn(0);
1872 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", "Ljava/lang/invoke/LambdaForm;");
1873 mv.visitInsn(Opcodes.SWAP); // swap form and array; avoid local variable
1874 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, LF, "interpretWithArguments", "([Ljava/lang/Object;)Ljava/lang/Object;", false);
1875
1876 // maybe unbox
1877 Class<?> rtype = invokerType.returnType();
1878 if (rtype.isPrimitive() && rtype != void.class) {
1879 emitUnboxing(Wrapper.forPrimitiveType(rtype));
1880 }
1881
1882 // return statement
1883 emitReturnInsn(basicType(rtype));
1884
1885 methodEpilogue();
1886 clinit(cw, className, classData);
1887 bogusMethod(invokerType);
1888
1889 final byte[] classFile = cw.toByteArray();
1890 maybeDump(classFile);
1891 return classFile;
1892 }
1893
1894 /**
1895 * Generate bytecode for a NamedFunction invoker.
1896 */
1897 static MemberName generateNamedFunctionInvoker(MethodTypeForm typeForm) {
1898 MethodType invokerType = NamedFunction.INVOKER_METHOD_TYPE;
1899 String invokerName = "invoke_" + shortenSignature(basicTypeSignature(typeForm.erasedType()));
1900 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("NFI", invokerName, invokerType);
1901 return g.loadMethod(g.generateNamedFunctionInvokerImpl(typeForm));
1902 }
1903
1904 private byte[] generateNamedFunctionInvokerImpl(MethodTypeForm typeForm) {
1905 MethodType dstType = typeForm.erasedType();
1906 classFilePrologue();
1907 methodPrologue();
1908
1909 // Suppress this method in backtraces displayed to the user.
1910 mv.visitAnnotation(HIDDEN_SIG, true);
1911
1912 // Force inlining of this invoker method.
1913 mv.visitAnnotation(FORCEINLINE_SIG, true);
1914
1915 // Load receiver
1916 emitAloadInsn(0);
1917
1918 // Load arguments from array
1919 for (int i = 0; i < dstType.parameterCount(); i++) {
1920 emitAloadInsn(1);
1921 emitIconstInsn(i);
1922 mv.visitInsn(Opcodes.AALOAD);
1923
1924 // Maybe unbox
1925 Class<?> dptype = dstType.parameterType(i);
1926 if (dptype.isPrimitive()) {
1927 Wrapper dstWrapper = Wrapper.forBasicType(dptype);
1928 Wrapper srcWrapper = dstWrapper.isSubwordOrInt() ? Wrapper.INT : dstWrapper; // narrow subword from int
1929 emitUnboxing(srcWrapper);
1930 emitPrimCast(srcWrapper, dstWrapper);
1931 }
1932 }
1933
1934 // Invoke
1935 String targetDesc = dstType.basicType().toMethodDescriptorString();
1936 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", targetDesc, false);
1937
1938 // Box primitive types
1939 Class<?> rtype = dstType.returnType();
1940 if (rtype != void.class && rtype.isPrimitive()) {
1941 Wrapper srcWrapper = Wrapper.forBasicType(rtype);
1942 Wrapper dstWrapper = srcWrapper.isSubwordOrInt() ? Wrapper.INT : srcWrapper; // widen subword to int
1943 // boolean casts not allowed
1944 emitPrimCast(srcWrapper, dstWrapper);
1945 emitBoxing(dstWrapper);
1946 }
1947
1948 // If the return type is void we return a null reference.
1949 if (rtype == void.class) {
1950 mv.visitInsn(Opcodes.ACONST_NULL);
1951 }
1952 emitReturnInsn(L_TYPE); // NOTE: NamedFunction invokers always return a reference value.
1953
1954 methodEpilogue();
1955 clinit(cw, className, classData);
1956 bogusMethod(dstType);
1957
1958 final byte[] classFile = cw.toByteArray();
1959 maybeDump(classFile);
1960 return classFile;
1961 }
1962
1963 /**
1964 * Emit a bogus method that just loads some string constants. This is to get the constants into the constant pool
1965 * for debugging purposes.
1966 */
1967 private void bogusMethod(Object os) {
1968 if (DUMP_CLASS_FILES) {
1969 mv = cw.visitMethod(Opcodes.ACC_STATIC, "dummy", "()V", null, null);
1970 mv.visitLdcInsn(os.toString());
1971 mv.visitInsn(Opcodes.POP);
1972 mv.visitInsn(Opcodes.RETURN);
1973 mv.visitMaxs(0, 0);
1974 mv.visitEnd();
1975 }
1976 }
1977 }