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.stream.Stream;
48
49 import static java.lang.invoke.LambdaForm.BasicType;
50 import static java.lang.invoke.LambdaForm.BasicType.*;
51 import static java.lang.invoke.LambdaForm.*;
52 import static java.lang.invoke.MethodHandleNatives.Constants.*;
53 import static java.lang.invoke.MethodHandleStatics.*;
54 import static java.lang.invoke.MethodHandles.Lookup.*;
55
56 /**
57 * Code generation backend for LambdaForm.
58 * <p>
59 * @author John Rose, JSR 292 EG
60 */
61 class InvokerBytecodeGenerator {
62 /** Define class names for convenience. */
63 private static final String MH = "java/lang/invoke/MethodHandle";
64 private static final String MHI = "java/lang/invoke/MethodHandleImpl";
65 private static final String LF = "java/lang/invoke/LambdaForm";
66 private static final String LFN = "java/lang/invoke/LambdaForm$Name";
67 private static final String CLS = "java/lang/Class";
68 private static final String OBJ = "java/lang/Object";
69 private static final String OBJARY = "[Ljava/lang/Object;";
70
71 private static final String LOOP_CLAUSES = MHI + "$LoopClauses";
72 private static final String MHARY2 = "[[L" + MH + ";";
73 private static final String MH_SIG = "L" + MH + ";";
74
75
76 private static final String LF_SIG = "L" + LF + ";";
77 private static final String LFN_SIG = "L" + LFN + ";";
78 private static final String LL_SIG = "(L" + OBJ + ";)L" + OBJ + ";";
79 private static final String LLV_SIG = "(L" + OBJ + ";L" + OBJ + ";)V";
80 private static final String CLASS_PREFIX = LF + "$";
81 private static final String SOURCE_PREFIX = "LambdaForm$";
82
83 /** Name of its super class*/
84 static final String INVOKER_SUPER_NAME = OBJ;
85
86 /** Name of new class */
87 private final String name;
88 private final String className;
89
90 private final LambdaForm lambdaForm;
91 private final String invokerName;
92 private final MethodType invokerType;
93
94 /** Info about local variables in compiled lambda form */
95 private int[] localsMap; // index
96 private Class<?>[] localClasses; // type
97
98 /** ASM bytecode generation. */
99 private ClassWriter cw;
100 private MethodVisitor mv;
101 private final List<ClassData> classData = new ArrayList<>();
102
103 /** Single element internal class name lookup cache. */
104 private Class<?> lastClass;
105 private String lastInternalName;
106
107 private static final MemberName.Factory MEMBERNAME_FACTORY = MemberName.getFactory();
108 private static final Class<?> HOST_CLASS = LambdaForm.class;
109 private static final MethodHandles.Lookup LOOKUP = lookup();
110
111 private static MethodHandles.Lookup lookup() {
112 try {
113 return MethodHandles.privateLookupIn(HOST_CLASS, IMPL_LOOKUP);
114 } catch (IllegalAccessException e) {
115 throw newInternalError(e);
116 }
117 }
118
119 /** Main constructor; other constructors delegate to this one. */
120 private InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize,
121 String name, String invokerName, MethodType invokerType) {
122 int p = invokerName.indexOf('.');
123 if (p > -1) {
124 name = invokerName.substring(0, p);
125 invokerName = invokerName.substring(p + 1);
126 }
127 if (DUMP_CLASS_FILES) {
128 name = makeDumpableClassName(name);
129 }
130 this.name = name;
131 this.className = CLASS_PREFIX + name;
132 this.lambdaForm = lambdaForm;
133 this.invokerName = invokerName;
134 this.invokerType = invokerType;
135 this.localsMap = new int[localsMapSize+1]; // last entry of localsMap is count of allocated local slots
136 this.localClasses = new Class<?>[localsMapSize+1];
137 }
138
139 /** For generating LambdaForm interpreter entry points. */
140 private InvokerBytecodeGenerator(String name, String invokerName, MethodType invokerType) {
141 this(null, invokerType.parameterCount(),
142 name, invokerName, invokerType);
143 MethodType mt = invokerType.erase();
144 // Create an array to map name indexes to locals indexes.
145 localsMap[0] = 0; // localsMap has at least one element
146 for (int i = 1, index = 0; i < localsMap.length; i++) {
147 Wrapper w = Wrapper.forBasicType(mt.parameterType(i - 1));
148 index += w.stackSlots();
149 localsMap[i] = index;
150 }
151 }
152
153 /** For generating customized code for a single LambdaForm. */
154 private InvokerBytecodeGenerator(String name, LambdaForm form, MethodType invokerType) {
155 this(name, form.lambdaName(), form, invokerType);
156 }
157
158 /** For generating customized code for a single LambdaForm. */
159 InvokerBytecodeGenerator(String name, String invokerName,
160 LambdaForm form, MethodType invokerType) {
161 this(form, form.names.length,
162 name, invokerName, invokerType);
163 // Create an array to map name indexes to locals indexes.
164 Name[] names = form.names;
165 for (int i = 0, index = 0; i < localsMap.length; i++) {
166 localsMap[i] = index;
167 if (i < names.length) {
168 BasicType type = names[i].type();
169 index += type.basicTypeSlots();
170 }
171 }
172 }
173
174 /** instance counters for dumped classes */
175 private static final HashMap<String,Integer> DUMP_CLASS_FILES_COUNTERS;
176 /** debugging flag for saving generated class files */
177 private static final File DUMP_CLASS_FILES_DIR;
178
179 static {
180 if (DUMP_CLASS_FILES) {
181 DUMP_CLASS_FILES_COUNTERS = new HashMap<>();
182 try {
183 File dumpDir = new File("DUMP_CLASS_FILES");
184 if (!dumpDir.exists()) {
185 dumpDir.mkdirs();
186 }
187 DUMP_CLASS_FILES_DIR = dumpDir;
188 System.out.println("Dumping class files to "+DUMP_CLASS_FILES_DIR+"/...");
189 } catch (Exception e) {
190 throw newInternalError(e);
191 }
192 } else {
193 DUMP_CLASS_FILES_COUNTERS = null;
194 DUMP_CLASS_FILES_DIR = null;
195 }
196 }
197
198 private void maybeDump(final byte[] classFile) {
199 if (DUMP_CLASS_FILES) {
200 maybeDump(className, classFile);
201 }
202 }
203
204 // Also used from BoundMethodHandle
205 @SuppressWarnings("removal")
206 static void maybeDump(final String className, final byte[] classFile) {
207 if (DUMP_CLASS_FILES) {
208 java.security.AccessController.doPrivileged(
209 new java.security.PrivilegedAction<>() {
210 public Void run() {
211 try {
212 String dumpName = className.replace('.','/');
213 File dumpFile = new File(DUMP_CLASS_FILES_DIR, dumpName+".class");
214 System.out.println("dump: " + dumpFile);
215 dumpFile.getParentFile().mkdirs();
216 FileOutputStream file = new FileOutputStream(dumpFile);
217 file.write(classFile);
218 file.close();
219 return null;
220 } catch (IOException ex) {
221 throw newInternalError(ex);
222 }
223 }
224 });
225 }
226 }
227
228 private static String makeDumpableClassName(String className) {
229 Integer ctr;
230 synchronized (DUMP_CLASS_FILES_COUNTERS) {
231 ctr = DUMP_CLASS_FILES_COUNTERS.get(className);
232 if (ctr == null) ctr = 0;
233 DUMP_CLASS_FILES_COUNTERS.put(className, ctr+1);
234 }
235 String sfx = ctr.toString();
236 while (sfx.length() < 3)
237 sfx = "0" + sfx;
238 className += sfx;
239 return className;
240 }
241
242 static class ClassData {
243 final String name;
244 final String desc;
245 final Object value;
246
247 ClassData(String name, String desc, Object value) {
248 this.name = name;
249 this.desc = desc;
250 this.value = value;
251 }
252
253 public String name() { return name; }
254 public String toString() {
255 return name + ",value="+value;
256 }
257 }
258
259 String classData(Object arg) {
260 String desc;
261 if (arg instanceof Class) {
262 desc = "Ljava/lang/Class;";
263 } else if (arg instanceof MethodHandle) {
264 desc = MH_SIG;
265 } else if (arg instanceof LambdaForm) {
266 desc = LF_SIG;
267 } else {
268 desc = "Ljava/lang/Object;";
269 }
270
271 // unique static variable name
272 String name;
273 if (DUMP_CLASS_FILES) {
274 Class<?> c = arg.getClass();
275 while (c.isArray()) {
276 c = c.getComponentType();
277 }
278 name = "_DATA_" + c.getSimpleName() + "_" + classData.size();
279 } else {
280 name = "_D_" + classData.size();
281 }
282 ClassData cd = new ClassData(name, desc, arg);
283 classData.add(cd);
284 return name;
285 }
286
287 List<Object> classDataValues() {
288 final List<ClassData> cd = classData;
289 return switch(cd.size()) {
290 case 0 -> List.of();
291 case 1 -> List.of(cd.get(0).value);
292 case 2 -> List.of(cd.get(0).value, cd.get(1).value);
293 case 3 -> List.of(cd.get(0).value, cd.get(1).value, cd.get(2).value);
294 case 4 -> List.of(cd.get(0).value, cd.get(1).value, cd.get(2).value, cd.get(3).value);
295 default -> {
296 Object[] data = new Object[classData.size()];
297 for (int i = 0; i < classData.size(); i++) {
298 data[i] = classData.get(i).value;
299 }
300 yield List.of(data);
301 }
302 };
303 }
304
305 private static String debugString(Object arg) {
306 if (arg instanceof MethodHandle mh) {
307 MemberName member = mh.internalMemberName();
308 if (member != null)
309 return member.toString();
310 return mh.debugString();
311 }
312 return arg.toString();
313 }
314
315 /**
316 * Extract the MemberName of a newly-defined method.
317 */
318 private MemberName loadMethod(byte[] classFile) {
319 Class<?> invokerClass = LOOKUP.makeHiddenClassDefiner(className, classFile)
320 .defineClass(true, classDataValues());
321 return resolveInvokerMember(invokerClass, invokerName, invokerType);
322 }
323
324 private static MemberName resolveInvokerMember(Class<?> invokerClass, String name, MethodType type) {
325 MemberName member = new MemberName(invokerClass, name, type, REF_invokeStatic);
326 try {
327 member = MEMBERNAME_FACTORY.resolveOrFail(REF_invokeStatic, member,
328 HOST_CLASS, LM_TRUSTED,
329 ReflectiveOperationException.class);
330 } catch (ReflectiveOperationException e) {
331 throw newInternalError(e);
332 }
333 return member;
334 }
335
336 /**
337 * Set up class file generation.
338 */
339 private ClassWriter classFilePrologue() {
340 final int NOT_ACC_PUBLIC = 0; // not ACC_PUBLIC
341 ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
342 setClassWriter(cw);
343 cw.visit(CLASSFILE_VERSION, NOT_ACC_PUBLIC + Opcodes.ACC_FINAL + Opcodes.ACC_SUPER,
344 className, null, INVOKER_SUPER_NAME, null);
345 cw.visitSource(SOURCE_PREFIX + name, null);
346 return cw;
347 }
348
349 private void methodPrologue() {
350 String invokerDesc = invokerType.toMethodDescriptorString();
351 mv = cw.visitMethod(Opcodes.ACC_STATIC, invokerName, invokerDesc, null, null);
352 }
353
354 /**
355 * Tear down class file generation.
356 */
357 private void methodEpilogue() {
358 mv.visitMaxs(0, 0);
359 mv.visitEnd();
360 }
361
362 /*
363 * <clinit> to initialize the static final fields with the live class data
364 * LambdaForms can't use condy due to bootstrapping issue.
365 */
366 static void clinit(ClassWriter cw, String className, List<ClassData> classData) {
367 if (classData.isEmpty())
368 return;
369
370 for (ClassData p : classData) {
371 // add the static field
372 FieldVisitor fv = cw.visitField(Opcodes.ACC_STATIC|Opcodes.ACC_FINAL, p.name, p.desc, null, null);
373 fv.visitEnd();
374 }
375
376 MethodVisitor mv = cw.visitMethod(Opcodes.ACC_STATIC, "<clinit>", "()V", null, null);
377 mv.visitCode();
378 mv.visitLdcInsn(Type.getType("L" + className + ";"));
379 mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/invoke/MethodHandleNatives",
380 "classData", "(Ljava/lang/Class;)Ljava/lang/Object;", false);
381 // we should optimize one single element case that does not need to create a List
382 mv.visitTypeInsn(Opcodes.CHECKCAST, "java/util/List");
383 mv.visitVarInsn(Opcodes.ASTORE, 0);
384 int index = 0;
385 for (ClassData p : classData) {
386 // initialize the static field
387 mv.visitVarInsn(Opcodes.ALOAD, 0);
388 emitIconstInsn(mv, index++);
389 mv.visitMethodInsn(Opcodes.INVOKEINTERFACE, "java/util/List",
390 "get", "(I)Ljava/lang/Object;", true);
391 mv.visitTypeInsn(Opcodes.CHECKCAST, p.desc.substring(1, p.desc.length()-1));
392 mv.visitFieldInsn(Opcodes.PUTSTATIC, className, p.name, p.desc);
393 }
394 mv.visitInsn(Opcodes.RETURN);
395 mv.visitMaxs(2, 1);
396 mv.visitEnd();
397 }
398
399 /*
400 * Low-level emit helpers.
401 */
402 private void emitConst(Object con) {
403 if (con == null) {
404 mv.visitInsn(Opcodes.ACONST_NULL);
405 return;
406 }
407 if (con instanceof Integer) {
408 emitIconstInsn((int) con);
409 return;
410 }
411 if (con instanceof Byte) {
412 emitIconstInsn((byte)con);
413 return;
414 }
415 if (con instanceof Short) {
416 emitIconstInsn((short)con);
417 return;
418 }
419 if (con instanceof Character) {
420 emitIconstInsn((char)con);
421 return;
422 }
423 if (con instanceof Long) {
424 long x = (long) con;
425 short sx = (short)x;
426 if (x == sx) {
427 if (sx >= 0 && sx <= 1) {
428 mv.visitInsn(Opcodes.LCONST_0 + (int) sx);
429 } else {
430 emitIconstInsn((int) x);
431 mv.visitInsn(Opcodes.I2L);
432 }
433 return;
434 }
435 }
436 if (con instanceof Float) {
437 float x = (float) con;
438 short sx = (short)x;
439 if (x == sx) {
440 if (sx >= 0 && sx <= 2) {
441 mv.visitInsn(Opcodes.FCONST_0 + (int) sx);
442 } else {
443 emitIconstInsn((int) x);
444 mv.visitInsn(Opcodes.I2F);
445 }
446 return;
447 }
448 }
449 if (con instanceof Double) {
450 double x = (double) con;
451 short sx = (short)x;
452 if (x == sx) {
453 if (sx >= 0 && sx <= 1) {
454 mv.visitInsn(Opcodes.DCONST_0 + (int) sx);
455 } else {
456 emitIconstInsn((int) x);
457 mv.visitInsn(Opcodes.I2D);
458 }
459 return;
460 }
461 }
462 if (con instanceof Boolean) {
463 emitIconstInsn((boolean) con ? 1 : 0);
464 return;
465 }
466 // fall through:
467 mv.visitLdcInsn(con);
468 }
469
470 private void emitIconstInsn(final int cst) {
471 emitIconstInsn(mv, cst);
472 }
473
474 private static void emitIconstInsn(MethodVisitor mv, int cst) {
475 if (cst >= -1 && cst <= 5) {
476 mv.visitInsn(Opcodes.ICONST_0 + cst);
477 } else if (cst >= Byte.MIN_VALUE && cst <= Byte.MAX_VALUE) {
478 mv.visitIntInsn(Opcodes.BIPUSH, cst);
479 } else if (cst >= Short.MIN_VALUE && cst <= Short.MAX_VALUE) {
480 mv.visitIntInsn(Opcodes.SIPUSH, cst);
481 } else {
482 mv.visitLdcInsn(cst);
483 }
484 }
485
486 /*
487 * NOTE: These load/store methods use the localsMap to find the correct index!
488 */
489 private void emitLoadInsn(BasicType type, int index) {
490 int opcode = loadInsnOpcode(type);
491 mv.visitVarInsn(opcode, localsMap[index]);
492 }
493
494 private int loadInsnOpcode(BasicType type) throws InternalError {
495 return switch (type) {
496 case I_TYPE -> Opcodes.ILOAD;
497 case J_TYPE -> Opcodes.LLOAD;
498 case F_TYPE -> Opcodes.FLOAD;
499 case D_TYPE -> Opcodes.DLOAD;
500 case L_TYPE -> Opcodes.ALOAD;
501 default -> throw new InternalError("unknown type: " + type);
502 };
503 }
504 private void emitAloadInsn(int index) {
505 emitLoadInsn(L_TYPE, index);
506 }
507
508 private void emitStoreInsn(BasicType type, int index) {
509 int opcode = storeInsnOpcode(type);
510 mv.visitVarInsn(opcode, localsMap[index]);
511 }
512
513 private int storeInsnOpcode(BasicType type) throws InternalError {
514 return switch (type) {
515 case I_TYPE -> Opcodes.ISTORE;
516 case J_TYPE -> Opcodes.LSTORE;
517 case F_TYPE -> Opcodes.FSTORE;
518 case D_TYPE -> Opcodes.DSTORE;
519 case L_TYPE -> Opcodes.ASTORE;
520 default -> throw new InternalError("unknown type: " + type);
521 };
522 }
523 private void emitAstoreInsn(int index) {
524 emitStoreInsn(L_TYPE, index);
525 }
526
527 private byte arrayTypeCode(Wrapper elementType) {
528 return (byte) switch (elementType) {
529 case BOOLEAN -> Opcodes.T_BOOLEAN;
530 case BYTE -> Opcodes.T_BYTE;
531 case CHAR -> Opcodes.T_CHAR;
532 case SHORT -> Opcodes.T_SHORT;
533 case INT -> Opcodes.T_INT;
534 case LONG -> Opcodes.T_LONG;
535 case FLOAT -> Opcodes.T_FLOAT;
536 case DOUBLE -> Opcodes.T_DOUBLE;
537 case OBJECT -> 0; // in place of Opcodes.T_OBJECT
538 default -> throw new InternalError();
539 };
540 }
541
542 private int arrayInsnOpcode(byte tcode, int aaop) throws InternalError {
543 assert(aaop == Opcodes.AASTORE || aaop == Opcodes.AALOAD);
544 int xas = switch (tcode) {
545 case Opcodes.T_BOOLEAN -> Opcodes.BASTORE;
546 case Opcodes.T_BYTE -> Opcodes.BASTORE;
547 case Opcodes.T_CHAR -> Opcodes.CASTORE;
548 case Opcodes.T_SHORT -> Opcodes.SASTORE;
549 case Opcodes.T_INT -> Opcodes.IASTORE;
550 case Opcodes.T_LONG -> Opcodes.LASTORE;
551 case Opcodes.T_FLOAT -> Opcodes.FASTORE;
552 case Opcodes.T_DOUBLE -> Opcodes.DASTORE;
553 case 0 -> Opcodes.AASTORE;
554 default -> throw new InternalError();
555 };
556 return xas - Opcodes.AASTORE + aaop;
557 }
558
559 /**
560 * Emit a boxing call.
561 *
562 * @param wrapper primitive type class to box.
563 */
564 private void emitBoxing(Wrapper wrapper) {
565 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
566 String name = "valueOf";
567 String desc = "(" + wrapper.basicTypeChar() + ")L" + owner + ";";
568 mv.visitMethodInsn(Opcodes.INVOKESTATIC, owner, name, desc, false);
569 }
570
571 /**
572 * Emit an unboxing call (plus preceding checkcast).
573 *
574 * @param wrapper wrapper type class to unbox.
575 */
576 private void emitUnboxing(Wrapper wrapper) {
577 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
578 String name = wrapper.primitiveSimpleName() + "Value";
579 String desc = "()" + wrapper.basicTypeChar();
580 emitReferenceCast(wrapper.wrapperType(), null);
581 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, owner, name, desc, false);
582 }
583
584 /**
585 * Emit an implicit conversion for an argument which must be of the given pclass.
586 * This is usually a no-op, except when pclass is a subword type or a reference other than Object or an interface.
587 *
588 * @param ptype type of value present on stack
589 * @param pclass type of value required on stack
590 * @param arg compile-time representation of value on stack (Node, constant) or null if none
591 */
592 private void emitImplicitConversion(BasicType ptype, Class<?> pclass, Object arg) {
593 assert(basicType(pclass) == ptype); // boxing/unboxing handled by caller
594 if (pclass == ptype.basicTypeClass() && ptype != L_TYPE)
595 return; // nothing to do
596 switch (ptype) {
597 case L_TYPE:
598 if (VerifyType.isNullConversion(Object.class, pclass, false)) {
599 if (PROFILE_LEVEL > 0)
600 emitReferenceCast(Object.class, arg);
601 return;
602 }
603 emitReferenceCast(pclass, arg);
604 return;
605 case I_TYPE:
606 if (!VerifyType.isNullConversion(int.class, pclass, false))
607 emitPrimCast(ptype.basicTypeWrapper(), Wrapper.forPrimitiveType(pclass));
608 return;
609 }
610 throw newInternalError("bad implicit conversion: tc="+ptype+": "+pclass);
611 }
612
613 /** Update localClasses type map. Return true if the information is already present. */
614 private boolean assertStaticType(Class<?> cls, Name n) {
615 int local = n.index();
616 Class<?> aclass = localClasses[local];
617 if (aclass != null && (aclass == cls || cls.isAssignableFrom(aclass))) {
618 return true; // type info is already present
619 } else if (aclass == null || aclass.isAssignableFrom(cls)) {
620 localClasses[local] = cls; // type info can be improved
621 }
622 return false;
623 }
624
625 private void emitReferenceCast(Class<?> cls, Object arg) {
626 Name writeBack = null; // local to write back result
627 if (arg instanceof Name n) {
628 if (lambdaForm.useCount(n) > 1) {
629 // This guy gets used more than once.
630 writeBack = n;
631 if (assertStaticType(cls, n)) {
632 return; // this cast was already performed
633 }
634 }
635 }
636 if (isStaticallyNameable(cls)) {
637 String sig = getInternalName(cls);
638 mv.visitTypeInsn(Opcodes.CHECKCAST, sig);
639 } else {
640 mv.visitFieldInsn(Opcodes.GETSTATIC, className, classData(cls), "Ljava/lang/Class;");
641 mv.visitInsn(Opcodes.SWAP);
642 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, CLS, "cast", LL_SIG, false);
643 if (Object[].class.isAssignableFrom(cls))
644 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJARY);
645 else if (PROFILE_LEVEL > 0)
646 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJ);
647 }
648 if (writeBack != null) {
649 mv.visitInsn(Opcodes.DUP);
650 emitAstoreInsn(writeBack.index());
651 }
652 }
653
654 /**
655 * Emits an actual return instruction conforming to the given return type.
656 */
657 private void emitReturnInsn(BasicType type) {
658 int opcode = switch (type) {
659 case I_TYPE -> Opcodes.IRETURN;
660 case J_TYPE -> Opcodes.LRETURN;
661 case F_TYPE -> Opcodes.FRETURN;
662 case D_TYPE -> Opcodes.DRETURN;
663 case L_TYPE -> Opcodes.ARETURN;
664 case V_TYPE -> Opcodes.RETURN;
665 default -> throw new InternalError("unknown return type: " + type);
666 };
667 mv.visitInsn(opcode);
668 }
669
670 private String getInternalName(Class<?> c) {
671 if (c == Object.class) return OBJ;
672 else if (c == Object[].class) return OBJARY;
673 else if (c == Class.class) return CLS;
674 else if (c == MethodHandle.class) return MH;
675 assert(VerifyAccess.isTypeVisible(c, Object.class)) : c.getName();
676
677 if (c == lastClass) {
678 return lastInternalName;
679 }
680 lastClass = c;
681 return lastInternalName = c.getName().replace('.', '/');
682 }
683
684 private static MemberName resolveFrom(String name, MethodType type, Class<?> holder) {
685 MemberName member = new MemberName(holder, name, type, REF_invokeStatic);
686 MemberName resolvedMember = MemberName.getFactory().resolveOrNull(REF_invokeStatic, member, holder, LM_TRUSTED);
687 traceLambdaForm(name, type, holder, resolvedMember);
688 return resolvedMember;
689 }
690
691 private static MemberName lookupPregenerated(LambdaForm form, MethodType invokerType) {
692 if (form.customized != null) {
693 // No pre-generated version for customized LF
694 return null;
695 }
696 String name = form.kind.methodName;
697 switch (form.kind) {
698 case BOUND_REINVOKER: {
699 name = name + "_" + BoundMethodHandle.speciesDataFor(form).key();
700 return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class);
701 }
702 case DELEGATE: return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class);
703 case ZERO: // fall-through
704 case IDENTITY: {
705 name = name + "_" + form.returnType().basicTypeChar();
706 return resolveFrom(name, invokerType, LambdaForm.Holder.class);
707 }
708 case EXACT_INVOKER: // fall-through
709 case EXACT_LINKER: // fall-through
710 case LINK_TO_CALL_SITE: // fall-through
711 case LINK_TO_TARGET_METHOD: // fall-through
712 case GENERIC_INVOKER: // fall-through
713 case GENERIC_LINKER: return resolveFrom(name, invokerType, Invokers.Holder.class);
714 case GET_REFERENCE: // fall-through
715 case GET_BOOLEAN: // fall-through
716 case GET_BYTE: // fall-through
717 case GET_CHAR: // fall-through
718 case GET_SHORT: // fall-through
719 case GET_INT: // fall-through
720 case GET_LONG: // fall-through
721 case GET_FLOAT: // fall-through
722 case GET_DOUBLE: // fall-through
723 case PUT_REFERENCE: // fall-through
724 case PUT_BOOLEAN: // fall-through
725 case PUT_BYTE: // fall-through
726 case PUT_CHAR: // fall-through
727 case PUT_SHORT: // fall-through
728 case PUT_INT: // fall-through
729 case PUT_LONG: // fall-through
730 case PUT_FLOAT: // fall-through
731 case PUT_DOUBLE: // fall-through
732 case DIRECT_NEW_INVOKE_SPECIAL: // fall-through
733 case DIRECT_INVOKE_INTERFACE: // fall-through
734 case DIRECT_INVOKE_SPECIAL: // fall-through
735 case DIRECT_INVOKE_SPECIAL_IFC: // fall-through
736 case DIRECT_INVOKE_STATIC: // fall-through
737 case DIRECT_INVOKE_STATIC_INIT: // fall-through
738 case DIRECT_INVOKE_VIRTUAL: return resolveFrom(name, invokerType, DirectMethodHandle.Holder.class);
739 }
740 return null;
741 }
742
743 /**
744 * Generate customized bytecode for a given LambdaForm.
745 */
746 static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) {
747 MemberName pregenerated = lookupPregenerated(form, invokerType);
748 if (pregenerated != null) return pregenerated; // pre-generated bytecode
749
750 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("MH", form, invokerType);
751 return g.loadMethod(g.generateCustomizedCodeBytes());
752 }
753
754 /** Generates code to check that actual receiver and LambdaForm matches */
755 private boolean checkActualReceiver() {
756 // Expects MethodHandle on the stack and actual receiver MethodHandle in slot #0
757 mv.visitInsn(Opcodes.DUP);
758 mv.visitVarInsn(Opcodes.ALOAD, localsMap[0]);
759 mv.visitMethodInsn(Opcodes.INVOKESTATIC, MHI, "assertSame", LLV_SIG, false);
760 return true;
761 }
762
763 static String className(String cn) {
764 assert checkClassName(cn): "Class not found: " + cn;
765 return cn;
766 }
767
768 static boolean checkClassName(String cn) {
769 Type tp = Type.getType(cn);
770 // additional sanity so only valid "L;" descriptors work
771 if (tp.getSort() != Type.OBJECT) {
772 return false;
773 }
774 try {
775 Class<?> c = Class.forName(tp.getClassName(), false, null);
776 return true;
777 } catch (ClassNotFoundException e) {
778 return false;
779 }
780 }
781
782 static final String DONTINLINE_SIG = className("Ljdk/internal/vm/annotation/DontInline;");
783 static final String FORCEINLINE_SIG = className("Ljdk/internal/vm/annotation/ForceInline;");
784 static final String HIDDEN_SIG = className("Ljdk/internal/vm/annotation/Hidden;");
785 static final String INJECTEDPROFILE_SIG = className("Ljava/lang/invoke/InjectedProfile;");
786 static final String LF_COMPILED_SIG = className("Ljava/lang/invoke/LambdaForm$Compiled;");
787
788 /**
789 * Generate an invoker method for the passed {@link LambdaForm}.
790 */
791 private byte[] generateCustomizedCodeBytes() {
792 classFilePrologue();
793 addMethod();
794 clinit(cw, className, classData);
795 bogusMethod(lambdaForm);
796
797 final byte[] classFile = toByteArray();
798 maybeDump(classFile);
799 return classFile;
800 }
801
802 void setClassWriter(ClassWriter cw) {
803 this.cw = cw;
804 }
805
806 void addMethod() {
807 methodPrologue();
808
809 // Suppress this method in backtraces displayed to the user.
810 mv.visitAnnotation(HIDDEN_SIG, true);
811
812 // Mark this method as a compiled LambdaForm
813 mv.visitAnnotation(LF_COMPILED_SIG, true);
814
815 if (lambdaForm.forceInline) {
816 // Force inlining of this invoker method.
817 mv.visitAnnotation(FORCEINLINE_SIG, true);
818 } else {
819 mv.visitAnnotation(DONTINLINE_SIG, true);
820 }
821
822 classData(lambdaForm); // keep LambdaForm instance & its compiled form lifetime tightly coupled.
823
824 if (lambdaForm.customized != null) {
825 // Since LambdaForm is customized for a particular MethodHandle, it's safe to substitute
826 // receiver MethodHandle (at slot #0) with an embedded constant and use it instead.
827 // It enables more efficient code generation in some situations, since embedded constants
828 // are compile-time constants for JIT compiler.
829 mv.visitFieldInsn(Opcodes.GETSTATIC, className, classData(lambdaForm.customized), MH_SIG);
830 mv.visitTypeInsn(Opcodes.CHECKCAST, MH);
831 assert(checkActualReceiver()); // expects MethodHandle on top of the stack
832 mv.visitVarInsn(Opcodes.ASTORE, localsMap[0]);
833 }
834
835 // iterate over the form's names, generating bytecode instructions for each
836 // start iterating at the first name following the arguments
837 Name onStack = null;
838 for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) {
839 Name name = lambdaForm.names[i];
840
841 emitStoreResult(onStack);
842 onStack = name; // unless otherwise modified below
843 MethodHandleImpl.Intrinsic intr = name.function.intrinsicName();
844 switch (intr) {
845 case SELECT_ALTERNATIVE:
846 assert lambdaForm.isSelectAlternative(i);
847 if (PROFILE_GWT) {
848 assert(name.arguments[0] instanceof Name &&
849 ((Name)name.arguments[0]).refersTo(MethodHandleImpl.class, "profileBoolean"));
850 mv.visitAnnotation(INJECTEDPROFILE_SIG, true);
851 }
852 onStack = emitSelectAlternative(name, lambdaForm.names[i+1]);
853 i++; // skip MH.invokeBasic of the selectAlternative result
854 continue;
855 case GUARD_WITH_CATCH:
856 assert lambdaForm.isGuardWithCatch(i);
857 onStack = emitGuardWithCatch(i);
858 i += 2; // jump to the end of GWC idiom
859 continue;
860 case TRY_FINALLY:
861 assert lambdaForm.isTryFinally(i);
862 onStack = emitTryFinally(i);
863 i += 2; // jump to the end of the TF idiom
864 continue;
865 case TABLE_SWITCH:
866 assert lambdaForm.isTableSwitch(i);
867 int numCases = (Integer) name.function.intrinsicData();
868 onStack = emitTableSwitch(i, numCases);
869 i += 2; // jump to the end of the TS idiom
870 continue;
871 case LOOP:
872 assert lambdaForm.isLoop(i);
873 onStack = emitLoop(i);
874 i += 2; // jump to the end of the LOOP idiom
875 continue;
876 case ARRAY_LOAD:
877 emitArrayLoad(name);
878 continue;
879 case ARRAY_STORE:
880 emitArrayStore(name);
881 continue;
882 case ARRAY_LENGTH:
883 emitArrayLength(name);
884 continue;
885 case IDENTITY:
886 assert(name.arguments.length == 1);
887 emitPushArguments(name, 0);
888 continue;
889 case ZERO:
890 assert(name.arguments.length == 0);
891 emitConst(name.type.basicTypeWrapper().zero());
892 continue;
893 case NONE:
894 // no intrinsic associated
895 break;
896 default:
897 throw newInternalError("Unknown intrinsic: "+intr);
898 }
899
900 MemberName member = name.function.member();
901 if (isStaticallyInvocable(member)) {
902 emitStaticInvoke(member, name);
903 } else {
904 emitInvoke(name);
905 }
906 }
907
908 // return statement
909 emitReturn(onStack);
910
911 methodEpilogue();
912 }
913
914 /*
915 * @throws BytecodeGenerationException if something goes wrong when
916 * generating the byte code
917 */
918 private byte[] toByteArray() {
919 try {
920 return cw.toByteArray();
921 } catch (RuntimeException e) {
922 throw new BytecodeGenerationException(e);
923 }
924 }
925
926 /**
927 * The BytecodeGenerationException.
928 */
929 @SuppressWarnings("serial")
930 static final class BytecodeGenerationException extends RuntimeException {
931 BytecodeGenerationException(Exception cause) {
932 super(cause);
933 }
934 }
935
936 void emitArrayLoad(Name name) { emitArrayOp(name, Opcodes.AALOAD); }
937 void emitArrayStore(Name name) { emitArrayOp(name, Opcodes.AASTORE); }
938 void emitArrayLength(Name name) { emitArrayOp(name, Opcodes.ARRAYLENGTH); }
939
940 void emitArrayOp(Name name, int arrayOpcode) {
941 assert arrayOpcode == Opcodes.AALOAD || arrayOpcode == Opcodes.AASTORE || arrayOpcode == Opcodes.ARRAYLENGTH;
942 Class<?> elementType = name.function.methodType().parameterType(0).getComponentType();
943 assert elementType != null;
944 emitPushArguments(name, 0);
945 if (arrayOpcode != Opcodes.ARRAYLENGTH && elementType.isPrimitive()) {
946 Wrapper w = Wrapper.forPrimitiveType(elementType);
947 arrayOpcode = arrayInsnOpcode(arrayTypeCode(w), arrayOpcode);
948 }
949 mv.visitInsn(arrayOpcode);
950 }
951
952 /**
953 * Emit an invoke for the given name.
954 */
955 void emitInvoke(Name name) {
956 assert(!name.isLinkerMethodInvoke()); // should use the static path for these
957 if (true) {
958 // push receiver
959 MethodHandle target = name.function.resolvedHandle();
960 assert(target != null) : name.exprString();
961 mv.visitFieldInsn(Opcodes.GETSTATIC, className, classData(target), MH_SIG);
962 emitReferenceCast(MethodHandle.class, target);
963 } else {
964 // load receiver
965 emitAloadInsn(0);
966 emitReferenceCast(MethodHandle.class, null);
967 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", LF_SIG);
968 mv.visitFieldInsn(Opcodes.GETFIELD, LF, "names", LFN_SIG);
969 // TODO more to come
970 }
971
972 // push arguments
973 emitPushArguments(name, 0);
974
975 // invocation
976 MethodType type = name.function.methodType();
977 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
978 }
979
980 private static final Class<?>[] STATICALLY_INVOCABLE_PACKAGES = {
981 // Sample classes from each package we are willing to bind to statically:
982 java.lang.Object.class,
983 java.util.Arrays.class,
984 jdk.internal.misc.Unsafe.class
985 //MethodHandle.class already covered
986 };
987
988 static boolean isStaticallyInvocable(NamedFunction ... functions) {
989 for (NamedFunction nf : functions) {
990 if (!isStaticallyInvocable(nf.member())) {
991 return false;
992 }
993 }
994 return true;
995 }
996
997 static boolean isStaticallyInvocable(Name name) {
998 return isStaticallyInvocable(name.function.member());
999 }
1000
1001 static boolean isStaticallyInvocable(MemberName member) {
1002 if (member == null) return false;
1003 if (member.isObjectConstructorOrStaticInitMethod()) return false;
1004
1005 Class<?> cls = member.getDeclaringClass();
1006 // Fast-path non-private members declared by MethodHandles, which is a common
1007 // case
1008 if (MethodHandle.class.isAssignableFrom(cls) && !member.isPrivate()) {
1009 assert(isStaticallyInvocableType(member.getMethodOrFieldType()));
1010 return true;
1011 }
1012 if (cls.isArray() || cls.isPrimitive())
1013 return false; // FIXME
1014 if (cls.isAnonymousClass() || cls.isLocalClass())
1015 return false; // inner class of some sort
1016 if (cls.getClassLoader() != MethodHandle.class.getClassLoader())
1017 return false; // not on BCP
1018 if (cls.isHidden())
1019 return false;
1020 if (!isStaticallyInvocableType(member.getMethodOrFieldType()))
1021 return false;
1022 if (!member.isPrivate() && VerifyAccess.isSamePackage(MethodHandle.class, cls))
1023 return true; // in java.lang.invoke package
1024 if (member.isPublic() && isStaticallyNameable(cls))
1025 return true;
1026 return false;
1027 }
1028
1029 private static boolean isStaticallyInvocableType(MethodType mtype) {
1030 if (!isStaticallyNameable(mtype.returnType()))
1031 return false;
1032 for (Class<?> ptype : mtype.parameterArray())
1033 if (!isStaticallyNameable(ptype))
1034 return false;
1035 return true;
1036 }
1037
1038 static boolean isStaticallyNameable(Class<?> cls) {
1039 if (cls == Object.class)
1040 return true;
1041 if (MethodHandle.class.isAssignableFrom(cls)) {
1042 assert(!cls.isHidden());
1043 return true;
1044 }
1045 while (cls.isArray())
1046 cls = cls.getComponentType();
1047 if (cls.isPrimitive())
1048 return true; // int[].class, for example
1049 if (cls.isHidden())
1050 return false;
1051 // could use VerifyAccess.isClassAccessible but the following is a safe approximation
1052 if (cls.getClassLoader() != Object.class.getClassLoader())
1053 return false;
1054 if (VerifyAccess.isSamePackage(MethodHandle.class, cls))
1055 return true;
1056 if (!Modifier.isPublic(cls.getModifiers()))
1057 return false;
1058 for (Class<?> pkgcls : STATICALLY_INVOCABLE_PACKAGES) {
1059 if (VerifyAccess.isSamePackage(pkgcls, cls))
1060 return true;
1061 }
1062 return false;
1063 }
1064
1065 void emitStaticInvoke(Name name) {
1066 emitStaticInvoke(name.function.member(), name);
1067 }
1068
1069 /**
1070 * Emit an invoke for the given name, using the MemberName directly.
1071 */
1072 void emitStaticInvoke(MemberName member, Name name) {
1073 assert(member.equals(name.function.member()));
1074 Class<?> defc = member.getDeclaringClass();
1075 String cname = getInternalName(defc);
1076 String mname = member.getName();
1077 String mtype;
1078 byte refKind = member.getReferenceKind();
1079 if (refKind == REF_invokeSpecial) {
1080 // in order to pass the verifier, we need to convert this to invokevirtual in all cases
1081 assert(member.canBeStaticallyBound()) : member;
1082 refKind = REF_invokeVirtual;
1083 }
1084
1085 assert(!(member.getDeclaringClass().isInterface() && refKind == REF_invokeVirtual));
1086
1087 // push arguments
1088 emitPushArguments(name, 0);
1089
1090 // invocation
1091 if (member.isMethod()) {
1092 mtype = member.getMethodType().toMethodDescriptorString();
1093 mv.visitMethodInsn(refKindOpcode(refKind), cname, mname, mtype,
1094 member.getDeclaringClass().isInterface());
1095 } else {
1096 mtype = MethodType.toFieldDescriptorString(member.getFieldType());
1097 mv.visitFieldInsn(refKindOpcode(refKind), cname, mname, mtype);
1098 }
1099 // Issue a type assertion for the result, so we can avoid casts later.
1100 if (name.type == L_TYPE) {
1101 Class<?> rtype = member.getInvocationType().returnType();
1102 assert(!rtype.isPrimitive());
1103 if (rtype != Object.class && !rtype.isInterface()) {
1104 assertStaticType(rtype, name);
1105 }
1106 }
1107 }
1108
1109 int refKindOpcode(byte refKind) {
1110 switch (refKind) {
1111 case REF_invokeVirtual: return Opcodes.INVOKEVIRTUAL;
1112 case REF_invokeStatic: return Opcodes.INVOKESTATIC;
1113 case REF_invokeSpecial: return Opcodes.INVOKESPECIAL;
1114 case REF_invokeInterface: return Opcodes.INVOKEINTERFACE;
1115 case REF_getField: return Opcodes.GETFIELD;
1116 case REF_putField: return Opcodes.PUTFIELD;
1117 case REF_getStatic: return Opcodes.GETSTATIC;
1118 case REF_putStatic: return Opcodes.PUTSTATIC;
1119 }
1120 throw new InternalError("refKind="+refKind);
1121 }
1122
1123 /**
1124 * Emit bytecode for the selectAlternative idiom.
1125 *
1126 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithTest):
1127 * <blockquote><pre>{@code
1128 * Lambda(a0:L,a1:I)=>{
1129 * t2:I=foo.test(a1:I);
1130 * t3:L=MethodHandleImpl.selectAlternative(t2:I,(MethodHandle(int)int),(MethodHandle(int)int));
1131 * t4:I=MethodHandle.invokeBasic(t3:L,a1:I);t4:I}
1132 * }</pre></blockquote>
1133 */
1134 private Name emitSelectAlternative(Name selectAlternativeName, Name invokeBasicName) {
1135 assert isStaticallyInvocable(invokeBasicName);
1136
1137 Name receiver = (Name) invokeBasicName.arguments[0];
1138
1139 Label L_fallback = new Label();
1140 Label L_done = new Label();
1141
1142 // load test result
1143 emitPushArgument(selectAlternativeName, 0);
1144
1145 // if_icmpne L_fallback
1146 mv.visitJumpInsn(Opcodes.IFEQ, L_fallback);
1147
1148 // invoke selectAlternativeName.arguments[1]
1149 Class<?>[] preForkClasses = localClasses.clone();
1150 emitPushArgument(selectAlternativeName, 1); // get 2nd argument of selectAlternative
1151 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
1152 emitStaticInvoke(invokeBasicName);
1153
1154 // goto L_done
1155 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1156
1157 // L_fallback:
1158 mv.visitLabel(L_fallback);
1159
1160 // invoke selectAlternativeName.arguments[2]
1161 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
1162 emitPushArgument(selectAlternativeName, 2); // get 3rd argument of selectAlternative
1163 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
1164 emitStaticInvoke(invokeBasicName);
1165
1166 // L_done:
1167 mv.visitLabel(L_done);
1168 // for now do not bother to merge typestate; just reset to the dominator state
1169 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
1170
1171 return invokeBasicName; // return what's on stack
1172 }
1173
1174 /**
1175 * Emit bytecode for the guardWithCatch idiom.
1176 *
1177 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithCatch):
1178 * <blockquote><pre>{@code
1179 * guardWithCatch=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{
1180 * t8:L=MethodHandle.invokeBasic(a4:L,a6:L,a7:L);
1181 * t9:L=MethodHandleImpl.guardWithCatch(a1:L,a2:L,a3:L,t8:L);
1182 * t10:I=MethodHandle.invokeBasic(a5:L,t9:L);t10:I}
1183 * }</pre></blockquote>
1184 *
1185 * It is compiled into bytecode equivalent of the following code:
1186 * <blockquote><pre>{@code
1187 * try {
1188 * return a1.invokeBasic(a6, a7);
1189 * } catch (Throwable e) {
1190 * if (!a2.isInstance(e)) throw e;
1191 * return a3.invokeBasic(ex, a6, a7);
1192 * }}</pre></blockquote>
1193 */
1194 private Name emitGuardWithCatch(int pos) {
1195 Name args = lambdaForm.names[pos];
1196 Name invoker = lambdaForm.names[pos+1];
1197 Name result = lambdaForm.names[pos+2];
1198
1199 Label L_startBlock = new Label();
1200 Label L_endBlock = new Label();
1201 Label L_handler = new Label();
1202 Label L_done = new Label();
1203
1204 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1205 MethodType type = args.function.resolvedHandle().type()
1206 .dropParameterTypes(0,1)
1207 .changeReturnType(returnType);
1208
1209 mv.visitTryCatchBlock(L_startBlock, L_endBlock, L_handler, "java/lang/Throwable");
1210
1211 // Normal case
1212 mv.visitLabel(L_startBlock);
1213 // load target
1214 emitPushArgument(invoker, 0);
1215 emitPushArguments(args, 1); // skip 1st argument: method handle
1216 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
1217 mv.visitLabel(L_endBlock);
1218 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1219
1220 // Exceptional case
1221 mv.visitLabel(L_handler);
1222
1223 // Check exception's type
1224 mv.visitInsn(Opcodes.DUP);
1225 // load exception class
1226 emitPushArgument(invoker, 1);
1227 mv.visitInsn(Opcodes.SWAP);
1228 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Class", "isInstance", "(Ljava/lang/Object;)Z", false);
1229 Label L_rethrow = new Label();
1230 mv.visitJumpInsn(Opcodes.IFEQ, L_rethrow);
1231
1232 // Invoke catcher
1233 // load catcher
1234 emitPushArgument(invoker, 2);
1235 mv.visitInsn(Opcodes.SWAP);
1236 emitPushArguments(args, 1); // skip 1st argument: method handle
1237 MethodType catcherType = type.insertParameterTypes(0, Throwable.class);
1238 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", catcherType.basicType().toMethodDescriptorString(), false);
1239 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1240
1241 mv.visitLabel(L_rethrow);
1242 mv.visitInsn(Opcodes.ATHROW);
1243
1244 mv.visitLabel(L_done);
1245
1246 return result;
1247 }
1248
1249 /**
1250 * Emit bytecode for the tryFinally idiom.
1251 * <p>
1252 * The pattern looks like (Cf. MethodHandleImpl.makeTryFinally):
1253 * <blockquote><pre>{@code
1254 * // a0: BMH
1255 * // a1: target, a2: cleanup
1256 * // a3: box, a4: unbox
1257 * // a5 (and following): arguments
1258 * tryFinally=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L)=>{
1259 * t6:L=MethodHandle.invokeBasic(a3:L,a5:L); // box the arguments into an Object[]
1260 * t7:L=MethodHandleImpl.tryFinally(a1:L,a2:L,t6:L); // call the tryFinally executor
1261 * t8:L=MethodHandle.invokeBasic(a4:L,t7:L);t8:L} // unbox the result; return the result
1262 * }</pre></blockquote>
1263 * <p>
1264 * It is compiled into bytecode equivalent to the following code:
1265 * <blockquote><pre>{@code
1266 * Throwable t;
1267 * Object r;
1268 * try {
1269 * r = a1.invokeBasic(a5);
1270 * } catch (Throwable thrown) {
1271 * t = thrown;
1272 * throw t;
1273 * } finally {
1274 * r = a2.invokeBasic(t, r, a5);
1275 * }
1276 * return r;
1277 * }</pre></blockquote>
1278 * <p>
1279 * Specifically, the bytecode will have the following form (the stack effects are given for the beginnings of
1280 * blocks, and for the situations after executing the given instruction - the code will have a slightly different
1281 * shape if the return type is {@code void}):
1282 * <blockquote><pre>{@code
1283 * TRY: (--)
1284 * load target (-- target)
1285 * load args (-- args... target)
1286 * INVOKEVIRTUAL MethodHandle.invokeBasic (depends)
1287 * FINALLY_NORMAL: (-- r_2nd* r)
1288 * store returned value (--)
1289 * load cleanup (-- cleanup)
1290 * ACONST_NULL (-- t cleanup)
1291 * load returned value (-- r_2nd* r t cleanup)
1292 * load args (-- args... r_2nd* r t cleanup)
1293 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r_2nd* r)
1294 * GOTO DONE
1295 * CATCH: (-- t)
1296 * DUP (-- t t)
1297 * FINALLY_EXCEPTIONAL: (-- t t)
1298 * load cleanup (-- cleanup t t)
1299 * SWAP (-- t cleanup t)
1300 * load default for r (-- r_2nd* r t cleanup t)
1301 * load args (-- args... r_2nd* r t cleanup t)
1302 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r_2nd* r t)
1303 * POP/POP2* (-- t)
1304 * ATHROW
1305 * DONE: (-- r)
1306 * }</pre></blockquote>
1307 * * = depends on whether the return type takes up 2 stack slots.
1308 */
1309 private Name emitTryFinally(int pos) {
1310 Name args = lambdaForm.names[pos];
1311 Name invoker = lambdaForm.names[pos+1];
1312 Name result = lambdaForm.names[pos+2];
1313
1314 Label lFrom = new Label();
1315 Label lTo = new Label();
1316 Label lCatch = new Label();
1317 Label lDone = new Label();
1318
1319 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1320 BasicType basicReturnType = BasicType.basicType(returnType);
1321 boolean isNonVoid = returnType != void.class;
1322
1323 MethodType type = args.function.resolvedHandle().type()
1324 .dropParameterTypes(0,1)
1325 .changeReturnType(returnType);
1326 MethodType cleanupType = type.insertParameterTypes(0, Throwable.class);
1327 if (isNonVoid) {
1328 cleanupType = cleanupType.insertParameterTypes(1, returnType);
1329 }
1330 String cleanupDesc = cleanupType.basicType().toMethodDescriptorString();
1331
1332 // exception handler table
1333 mv.visitTryCatchBlock(lFrom, lTo, lCatch, "java/lang/Throwable");
1334
1335 // TRY:
1336 mv.visitLabel(lFrom);
1337 emitPushArgument(invoker, 0); // load target
1338 emitPushArguments(args, 1); // load args (skip 0: method handle)
1339 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
1340 mv.visitLabel(lTo);
1341
1342 // FINALLY_NORMAL:
1343 int index = extendLocalsMap(new Class<?>[]{ returnType });
1344 if (isNonVoid) {
1345 emitStoreInsn(basicReturnType, index);
1346 }
1347 emitPushArgument(invoker, 1); // load cleanup
1348 mv.visitInsn(Opcodes.ACONST_NULL);
1349 if (isNonVoid) {
1350 emitLoadInsn(basicReturnType, index);
1351 }
1352 emitPushArguments(args, 1); // load args (skip 0: method handle)
1353 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", cleanupDesc, false);
1354 mv.visitJumpInsn(Opcodes.GOTO, lDone);
1355
1356 // CATCH:
1357 mv.visitLabel(lCatch);
1358 mv.visitInsn(Opcodes.DUP);
1359
1360 // FINALLY_EXCEPTIONAL:
1361 emitPushArgument(invoker, 1); // load cleanup
1362 mv.visitInsn(Opcodes.SWAP);
1363 if (isNonVoid) {
1364 emitZero(BasicType.basicType(returnType)); // load default for result
1365 }
1366 emitPushArguments(args, 1); // load args (skip 0: method handle)
1367 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", cleanupDesc, false);
1368 if (isNonVoid) {
1369 emitPopInsn(basicReturnType);
1370 }
1371 mv.visitInsn(Opcodes.ATHROW);
1372
1373 // DONE:
1374 mv.visitLabel(lDone);
1375
1376 return result;
1377 }
1378
1379 private void emitPopInsn(BasicType type) {
1380 mv.visitInsn(popInsnOpcode(type));
1381 }
1382
1383 private static int popInsnOpcode(BasicType type) {
1384 return switch (type) {
1385 case I_TYPE, F_TYPE, L_TYPE -> Opcodes.POP;
1386 case J_TYPE, D_TYPE -> Opcodes.POP2;
1387 default -> throw new InternalError("unknown type: " + type);
1388 };
1389 }
1390
1391 private Name emitTableSwitch(int pos, int numCases) {
1392 Name args = lambdaForm.names[pos];
1393 Name invoker = lambdaForm.names[pos + 1];
1394 Name result = lambdaForm.names[pos + 2];
1395
1396 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1397 MethodType caseType = args.function.resolvedHandle().type()
1398 .dropParameterTypes(0, 1) // drop collector
1399 .changeReturnType(returnType);
1400 String caseDescriptor = caseType.basicType().toMethodDescriptorString();
1401
1402 emitPushArgument(invoker, 2); // push cases
1403 mv.visitFieldInsn(Opcodes.GETFIELD, "java/lang/invoke/MethodHandleImpl$CasesHolder", "cases",
1404 "[Ljava/lang/invoke/MethodHandle;");
1405 int casesLocal = extendLocalsMap(new Class<?>[] { MethodHandle[].class });
1406 emitStoreInsn(L_TYPE, casesLocal);
1407
1408 Label endLabel = new Label();
1409 Label defaultLabel = new Label();
1410 Label[] caseLabels = new Label[numCases];
1411 for (int i = 0; i < caseLabels.length; i++) {
1412 caseLabels[i] = new Label();
1413 }
1414
1415 emitPushArgument(invoker, 0); // push switch input
1416 mv.visitTableSwitchInsn(0, numCases - 1, defaultLabel, caseLabels);
1417
1418 mv.visitLabel(defaultLabel);
1419 emitPushArgument(invoker, 1); // push default handle
1420 emitPushArguments(args, 1); // again, skip collector
1421 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", caseDescriptor, false);
1422 mv.visitJumpInsn(Opcodes.GOTO, endLabel);
1423
1424 for (int i = 0; i < numCases; i++) {
1425 mv.visitLabel(caseLabels[i]);
1426 // Load the particular case:
1427 emitLoadInsn(L_TYPE, casesLocal);
1428 emitIconstInsn(i);
1429 mv.visitInsn(Opcodes.AALOAD);
1430
1431 // invoke it:
1432 emitPushArguments(args, 1); // again, skip collector
1433 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", caseDescriptor, false);
1434
1435 mv.visitJumpInsn(Opcodes.GOTO, endLabel);
1436 }
1437
1438 mv.visitLabel(endLabel);
1439
1440 return result;
1441 }
1442
1443 /**
1444 * Emit bytecode for the loop idiom.
1445 * <p>
1446 * The pattern looks like (Cf. MethodHandleImpl.loop):
1447 * <blockquote><pre>{@code
1448 * // a0: BMH
1449 * // a1: LoopClauses (containing an array of arrays: inits, steps, preds, finis)
1450 * // a2: box, a3: unbox
1451 * // a4 (and following): arguments
1452 * loop=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L)=>{
1453 * t5:L=MethodHandle.invokeBasic(a2:L,a4:L); // box the arguments into an Object[]
1454 * t6:L=MethodHandleImpl.loop(bt:L,a1:L,t5:L); // call the loop executor (with supplied types in bt)
1455 * t7:L=MethodHandle.invokeBasic(a3:L,t6:L);t7:L} // unbox the result; return the result
1456 * }</pre></blockquote>
1457 * <p>
1458 * It is compiled into bytecode equivalent to the code seen in {@link MethodHandleImpl#loop(BasicType[],
1459 * MethodHandleImpl.LoopClauses, Object...)}, with the difference that no arrays
1460 * will be used for local state storage. Instead, the local state will be mapped to actual stack slots.
1461 * <p>
1462 * Bytecode generation applies an unrolling scheme to enable better bytecode generation regarding local state type
1463 * handling. The generated bytecode will have the following form ({@code void} types are ignored for convenience).
1464 * Assume there are {@code C} clauses in the loop.
1465 * <blockquote><pre>{@code
1466 * PREINIT: ALOAD_1
1467 * CHECKCAST LoopClauses
1468 * GETFIELD LoopClauses.clauses
1469 * ASTORE clauseDataIndex // place the clauses 2-dimensional array on the stack
1470 * INIT: (INIT_SEQ for clause 1)
1471 * ...
1472 * (INIT_SEQ for clause C)
1473 * LOOP: (LOOP_SEQ for clause 1)
1474 * ...
1475 * (LOOP_SEQ for clause C)
1476 * GOTO LOOP
1477 * DONE: ...
1478 * }</pre></blockquote>
1479 * <p>
1480 * The {@code INIT_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has
1481 * the following shape. Assume slot {@code vx} is used to hold the state for clause {@code x}.
1482 * <blockquote><pre>{@code
1483 * INIT_SEQ_x: ALOAD clauseDataIndex
1484 * ICONST_0
1485 * AALOAD // load the inits array
1486 * ICONST x
1487 * AALOAD // load the init handle for clause x
1488 * load args
1489 * INVOKEVIRTUAL MethodHandle.invokeBasic
1490 * store vx
1491 * }</pre></blockquote>
1492 * <p>
1493 * The {@code LOOP_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has
1494 * the following shape. Again, assume slot {@code vx} is used to hold the state for clause {@code x}.
1495 * <blockquote><pre>{@code
1496 * LOOP_SEQ_x: ALOAD clauseDataIndex
1497 * ICONST_1
1498 * AALOAD // load the steps array
1499 * ICONST x
1500 * AALOAD // load the step handle for clause x
1501 * load locals
1502 * load args
1503 * INVOKEVIRTUAL MethodHandle.invokeBasic
1504 * store vx
1505 * ALOAD clauseDataIndex
1506 * ICONST_2
1507 * AALOAD // load the preds array
1508 * ICONST x
1509 * AALOAD // load the pred handle for clause x
1510 * load locals
1511 * load args
1512 * INVOKEVIRTUAL MethodHandle.invokeBasic
1513 * IFNE LOOP_SEQ_x+1 // predicate returned false -> jump to next clause
1514 * ALOAD clauseDataIndex
1515 * ICONST_3
1516 * AALOAD // load the finis array
1517 * ICONST x
1518 * AALOAD // load the fini handle for clause x
1519 * load locals
1520 * load args
1521 * INVOKEVIRTUAL MethodHandle.invokeBasic
1522 * GOTO DONE // jump beyond end of clauses to return from loop
1523 * }</pre></blockquote>
1524 */
1525 private Name emitLoop(int pos) {
1526 Name args = lambdaForm.names[pos];
1527 Name invoker = lambdaForm.names[pos+1];
1528 Name result = lambdaForm.names[pos+2];
1529
1530 // extract clause and loop-local state types
1531 // find the type info in the loop invocation
1532 BasicType[] loopClauseTypes = (BasicType[]) invoker.arguments[0];
1533 Class<?>[] loopLocalStateTypes = Stream.of(loopClauseTypes).
1534 filter(bt -> bt != BasicType.V_TYPE).map(BasicType::basicTypeClass).toArray(Class<?>[]::new);
1535 Class<?>[] localTypes = new Class<?>[loopLocalStateTypes.length + 1];
1536 localTypes[0] = MethodHandleImpl.LoopClauses.class;
1537 System.arraycopy(loopLocalStateTypes, 0, localTypes, 1, loopLocalStateTypes.length);
1538
1539 final int clauseDataIndex = extendLocalsMap(localTypes);
1540 final int firstLoopStateIndex = clauseDataIndex + 1;
1541
1542 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1543 MethodType loopType = args.function.resolvedHandle().type()
1544 .dropParameterTypes(0,1)
1545 .changeReturnType(returnType);
1546 MethodType loopHandleType = loopType.insertParameterTypes(0, loopLocalStateTypes);
1547 MethodType predType = loopHandleType.changeReturnType(boolean.class);
1548 MethodType finiType = loopHandleType;
1549
1550 final int nClauses = loopClauseTypes.length;
1551
1552 // indices to invoker arguments to load method handle arrays
1553 final int inits = 1;
1554 final int steps = 2;
1555 final int preds = 3;
1556 final int finis = 4;
1557
1558 Label lLoop = new Label();
1559 Label lDone = new Label();
1560 Label lNext;
1561
1562 // PREINIT:
1563 emitPushArgument(MethodHandleImpl.LoopClauses.class, invoker.arguments[1]);
1564 mv.visitFieldInsn(Opcodes.GETFIELD, LOOP_CLAUSES, "clauses", MHARY2);
1565 emitAstoreInsn(clauseDataIndex);
1566
1567 // INIT:
1568 for (int c = 0, state = 0; c < nClauses; ++c) {
1569 MethodType cInitType = loopType.changeReturnType(loopClauseTypes[c].basicTypeClass());
1570 emitLoopHandleInvoke(invoker, inits, c, args, false, cInitType, loopLocalStateTypes, clauseDataIndex,
1571 firstLoopStateIndex);
1572 if (cInitType.returnType() != void.class) {
1573 emitStoreInsn(BasicType.basicType(cInitType.returnType()), firstLoopStateIndex + state);
1574 ++state;
1575 }
1576 }
1577
1578 // LOOP:
1579 mv.visitLabel(lLoop);
1580
1581 for (int c = 0, state = 0; c < nClauses; ++c) {
1582 lNext = new Label();
1583
1584 MethodType stepType = loopHandleType.changeReturnType(loopClauseTypes[c].basicTypeClass());
1585 boolean isVoid = stepType.returnType() == void.class;
1586
1587 // invoke loop step
1588 emitLoopHandleInvoke(invoker, steps, c, args, true, stepType, loopLocalStateTypes, clauseDataIndex,
1589 firstLoopStateIndex);
1590 if (!isVoid) {
1591 emitStoreInsn(BasicType.basicType(stepType.returnType()), firstLoopStateIndex + state);
1592 ++state;
1593 }
1594
1595 // invoke loop predicate
1596 emitLoopHandleInvoke(invoker, preds, c, args, true, predType, loopLocalStateTypes, clauseDataIndex,
1597 firstLoopStateIndex);
1598 mv.visitJumpInsn(Opcodes.IFNE, lNext);
1599
1600 // invoke fini
1601 emitLoopHandleInvoke(invoker, finis, c, args, true, finiType, loopLocalStateTypes, clauseDataIndex,
1602 firstLoopStateIndex);
1603 mv.visitJumpInsn(Opcodes.GOTO, lDone);
1604
1605 // this is the beginning of the next loop clause
1606 mv.visitLabel(lNext);
1607 }
1608
1609 mv.visitJumpInsn(Opcodes.GOTO, lLoop);
1610
1611 // DONE:
1612 mv.visitLabel(lDone);
1613
1614 return result;
1615 }
1616
1617 private int extendLocalsMap(Class<?>[] types) {
1618 int firstSlot = localsMap.length - 1;
1619 localsMap = Arrays.copyOf(localsMap, localsMap.length + types.length);
1620 localClasses = Arrays.copyOf(localClasses, localClasses.length + types.length);
1621 System.arraycopy(types, 0, localClasses, firstSlot, types.length);
1622 int index = localsMap[firstSlot - 1] + 1;
1623 int lastSlots = 0;
1624 for (int i = 0; i < types.length; ++i) {
1625 localsMap[firstSlot + i] = index;
1626 lastSlots = BasicType.basicType(localClasses[firstSlot + i]).basicTypeSlots();
1627 index += lastSlots;
1628 }
1629 localsMap[localsMap.length - 1] = index - lastSlots;
1630 return firstSlot;
1631 }
1632
1633 private void emitLoopHandleInvoke(Name holder, int handles, int clause, Name args, boolean pushLocalState,
1634 MethodType type, Class<?>[] loopLocalStateTypes, int clauseDataSlot,
1635 int firstLoopStateSlot) {
1636 // load handle for clause
1637 emitPushClauseArray(clauseDataSlot, handles);
1638 emitIconstInsn(clause);
1639 mv.visitInsn(Opcodes.AALOAD);
1640 // load loop state (preceding the other arguments)
1641 if (pushLocalState) {
1642 for (int s = 0; s < loopLocalStateTypes.length; ++s) {
1643 emitLoadInsn(BasicType.basicType(loopLocalStateTypes[s]), firstLoopStateSlot + s);
1644 }
1645 }
1646 // load loop args (skip 0: method handle)
1647 emitPushArguments(args, 1);
1648 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.toMethodDescriptorString(), false);
1649 }
1650
1651 private void emitPushClauseArray(int clauseDataSlot, int which) {
1652 emitAloadInsn(clauseDataSlot);
1653 emitIconstInsn(which - 1);
1654 mv.visitInsn(Opcodes.AALOAD);
1655 }
1656
1657 private void emitZero(BasicType type) {
1658 mv.visitInsn(switch (type) {
1659 case I_TYPE -> Opcodes.ICONST_0;
1660 case J_TYPE -> Opcodes.LCONST_0;
1661 case F_TYPE -> Opcodes.FCONST_0;
1662 case D_TYPE -> Opcodes.DCONST_0;
1663 case L_TYPE -> Opcodes.ACONST_NULL;
1664 default -> throw new InternalError("unknown type: " + type);
1665 });
1666 }
1667
1668 private void emitPushArguments(Name args, int start) {
1669 MethodType type = args.function.methodType();
1670 for (int i = start; i < args.arguments.length; i++) {
1671 emitPushArgument(type.parameterType(i), args.arguments[i]);
1672 }
1673 }
1674
1675 private void emitPushArgument(Name name, int paramIndex) {
1676 Object arg = name.arguments[paramIndex];
1677 Class<?> ptype = name.function.methodType().parameterType(paramIndex);
1678 emitPushArgument(ptype, arg);
1679 }
1680
1681 private void emitPushArgument(Class<?> ptype, Object arg) {
1682 BasicType bptype = basicType(ptype);
1683 if (arg instanceof Name n) {
1684 emitLoadInsn(n.type, n.index());
1685 emitImplicitConversion(n.type, ptype, n);
1686 } else if (arg == null && bptype == L_TYPE) {
1687 mv.visitInsn(Opcodes.ACONST_NULL);
1688 } else if (arg instanceof String && bptype == L_TYPE) {
1689 mv.visitLdcInsn(arg);
1690 } else {
1691 if (Wrapper.isWrapperType(arg.getClass()) && bptype != L_TYPE) {
1692 emitConst(arg);
1693 } else {
1694 mv.visitFieldInsn(Opcodes.GETSTATIC, className, classData(arg), "Ljava/lang/Object;");
1695 emitImplicitConversion(L_TYPE, ptype, arg);
1696 }
1697 }
1698 }
1699
1700 /**
1701 * Store the name to its local, if necessary.
1702 */
1703 private void emitStoreResult(Name name) {
1704 if (name != null && name.type != V_TYPE) {
1705 // non-void: actually assign
1706 emitStoreInsn(name.type, name.index());
1707 }
1708 }
1709
1710 /**
1711 * Emits a return statement from a LF invoker. If required, the result type is cast to the correct return type.
1712 */
1713 private void emitReturn(Name onStack) {
1714 // return statement
1715 Class<?> rclass = invokerType.returnType();
1716 BasicType rtype = lambdaForm.returnType();
1717 assert(rtype == basicType(rclass)); // must agree
1718 if (rtype == V_TYPE) {
1719 // void
1720 mv.visitInsn(Opcodes.RETURN);
1721 // it doesn't matter what rclass is; the JVM will discard any value
1722 } else {
1723 LambdaForm.Name rn = lambdaForm.names[lambdaForm.result];
1724
1725 // put return value on the stack if it is not already there
1726 if (rn != onStack) {
1727 emitLoadInsn(rtype, lambdaForm.result);
1728 }
1729
1730 emitImplicitConversion(rtype, rclass, rn);
1731
1732 // generate actual return statement
1733 emitReturnInsn(rtype);
1734 }
1735 }
1736
1737 /**
1738 * Emit a type conversion bytecode casting from "from" to "to".
1739 */
1740 private void emitPrimCast(Wrapper from, Wrapper to) {
1741 // Here's how.
1742 // - indicates forbidden
1743 // <-> indicates implicit
1744 // to ----> boolean byte short char int long float double
1745 // from boolean <-> - - - - - - -
1746 // byte - <-> i2s i2c <-> i2l i2f i2d
1747 // short - i2b <-> i2c <-> i2l i2f i2d
1748 // char - i2b i2s <-> <-> i2l i2f i2d
1749 // int - i2b i2s i2c <-> i2l i2f i2d
1750 // long - l2i,i2b l2i,i2s l2i,i2c l2i <-> l2f l2d
1751 // float - f2i,i2b f2i,i2s f2i,i2c f2i f2l <-> f2d
1752 // double - d2i,i2b d2i,i2s d2i,i2c d2i d2l d2f <->
1753 if (from == to) {
1754 // no cast required, should be dead code anyway
1755 return;
1756 }
1757 if (from.isSubwordOrInt()) {
1758 // cast from {byte,short,char,int} to anything
1759 emitI2X(to);
1760 } else {
1761 // cast from {long,float,double} to anything
1762 if (to.isSubwordOrInt()) {
1763 // cast to {byte,short,char,int}
1764 emitX2I(from);
1765 if (to.bitWidth() < 32) {
1766 // targets other than int require another conversion
1767 emitI2X(to);
1768 }
1769 } else {
1770 // cast to {long,float,double} - this is verbose
1771 boolean error = false;
1772 switch (from) {
1773 case LONG -> {
1774 switch (to) {
1775 case FLOAT -> mv.visitInsn(Opcodes.L2F);
1776 case DOUBLE -> mv.visitInsn(Opcodes.L2D);
1777 default -> error = true;
1778 }
1779 }
1780 case FLOAT -> {
1781 switch (to) {
1782 case LONG -> mv.visitInsn(Opcodes.F2L);
1783 case DOUBLE -> mv.visitInsn(Opcodes.F2D);
1784 default -> error = true;
1785 }
1786 }
1787 case DOUBLE -> {
1788 switch (to) {
1789 case LONG -> mv.visitInsn(Opcodes.D2L);
1790 case FLOAT -> mv.visitInsn(Opcodes.D2F);
1791 default -> error = true;
1792 }
1793 }
1794 default -> error = true;
1795 }
1796 if (error) {
1797 throw new IllegalStateException("unhandled prim cast: " + from + "2" + to);
1798 }
1799 }
1800 }
1801 }
1802
1803 private void emitI2X(Wrapper type) {
1804 switch (type) {
1805 case BYTE: mv.visitInsn(Opcodes.I2B); break;
1806 case SHORT: mv.visitInsn(Opcodes.I2S); break;
1807 case CHAR: mv.visitInsn(Opcodes.I2C); break;
1808 case INT: /* naught */ break;
1809 case LONG: mv.visitInsn(Opcodes.I2L); break;
1810 case FLOAT: mv.visitInsn(Opcodes.I2F); break;
1811 case DOUBLE: mv.visitInsn(Opcodes.I2D); break;
1812 case BOOLEAN:
1813 // For compatibility with ValueConversions and explicitCastArguments:
1814 mv.visitInsn(Opcodes.ICONST_1);
1815 mv.visitInsn(Opcodes.IAND);
1816 break;
1817 default: throw new InternalError("unknown type: " + type);
1818 }
1819 }
1820
1821 private void emitX2I(Wrapper type) {
1822 switch (type) {
1823 case LONG -> mv.visitInsn(Opcodes.L2I);
1824 case FLOAT -> mv.visitInsn(Opcodes.F2I);
1825 case DOUBLE -> mv.visitInsn(Opcodes.D2I);
1826 default -> throw new InternalError("unknown type: " + type);
1827 }
1828 }
1829
1830 /**
1831 * Generate bytecode for a LambdaForm.vmentry which calls interpretWithArguments.
1832 */
1833 static MemberName generateLambdaFormInterpreterEntryPoint(MethodType mt) {
1834 assert(isValidSignature(basicTypeSignature(mt)));
1835 String name = "interpret_"+basicTypeChar(mt.returnType());
1836 MethodType type = mt; // includes leading argument
1837 type = type.changeParameterType(0, MethodHandle.class);
1838 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("LFI", name, type);
1839 return g.loadMethod(g.generateLambdaFormInterpreterEntryPointBytes());
1840 }
1841
1842 private byte[] generateLambdaFormInterpreterEntryPointBytes() {
1843 classFilePrologue();
1844 methodPrologue();
1845
1846 // Suppress this method in backtraces displayed to the user.
1847 mv.visitAnnotation(HIDDEN_SIG, true);
1848
1849 // Don't inline the interpreter entry.
1850 mv.visitAnnotation(DONTINLINE_SIG, true);
1851
1852 // create parameter array
1853 emitIconstInsn(invokerType.parameterCount());
1854 mv.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object");
1855
1856 // fill parameter array
1857 for (int i = 0; i < invokerType.parameterCount(); i++) {
1858 Class<?> ptype = invokerType.parameterType(i);
1859 mv.visitInsn(Opcodes.DUP);
1860 emitIconstInsn(i);
1861 emitLoadInsn(basicType(ptype), i);
1862 // box if primitive type
1863 if (ptype.isPrimitive()) {
1864 emitBoxing(Wrapper.forPrimitiveType(ptype));
1865 }
1866 mv.visitInsn(Opcodes.AASTORE);
1867 }
1868 // invoke
1869 emitAloadInsn(0);
1870 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", "Ljava/lang/invoke/LambdaForm;");
1871 mv.visitInsn(Opcodes.SWAP); // swap form and array; avoid local variable
1872 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, LF, "interpretWithArguments", "([Ljava/lang/Object;)Ljava/lang/Object;", false);
1873
1874 // maybe unbox
1875 Class<?> rtype = invokerType.returnType();
1876 if (rtype.isPrimitive() && rtype != void.class) {
1877 emitUnboxing(Wrapper.forPrimitiveType(rtype));
1878 }
1879
1880 // return statement
1881 emitReturnInsn(basicType(rtype));
1882
1883 methodEpilogue();
1884 clinit(cw, className, classData);
1885 bogusMethod(invokerType);
1886
1887 final byte[] classFile = cw.toByteArray();
1888 maybeDump(classFile);
1889 return classFile;
1890 }
1891
1892 /**
1893 * Generate bytecode for a NamedFunction invoker.
1894 */
1895 static MemberName generateNamedFunctionInvoker(MethodTypeForm typeForm) {
1896 MethodType invokerType = NamedFunction.INVOKER_METHOD_TYPE;
1897 String invokerName = "invoke_" + shortenSignature(basicTypeSignature(typeForm.erasedType()));
1898 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("NFI", invokerName, invokerType);
1899 return g.loadMethod(g.generateNamedFunctionInvokerImpl(typeForm));
1900 }
1901
1902 private byte[] generateNamedFunctionInvokerImpl(MethodTypeForm typeForm) {
1903 MethodType dstType = typeForm.erasedType();
1904 classFilePrologue();
1905 methodPrologue();
1906
1907 // Suppress this method in backtraces displayed to the user.
1908 mv.visitAnnotation(HIDDEN_SIG, true);
1909
1910 // Force inlining of this invoker method.
1911 mv.visitAnnotation(FORCEINLINE_SIG, true);
1912
1913 // Load receiver
1914 emitAloadInsn(0);
1915
1916 // Load arguments from array
1917 for (int i = 0; i < dstType.parameterCount(); i++) {
1918 emitAloadInsn(1);
1919 emitIconstInsn(i);
1920 mv.visitInsn(Opcodes.AALOAD);
1921
1922 // Maybe unbox
1923 Class<?> dptype = dstType.parameterType(i);
1924 if (dptype.isPrimitive()) {
1925 Wrapper dstWrapper = Wrapper.forBasicType(dptype);
1926 Wrapper srcWrapper = dstWrapper.isSubwordOrInt() ? Wrapper.INT : dstWrapper; // narrow subword from int
1927 emitUnboxing(srcWrapper);
1928 emitPrimCast(srcWrapper, dstWrapper);
1929 }
1930 }
1931
1932 // Invoke
1933 String targetDesc = dstType.basicType().toMethodDescriptorString();
1934 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", targetDesc, false);
1935
1936 // Box primitive types
1937 Class<?> rtype = dstType.returnType();
1938 if (rtype != void.class && rtype.isPrimitive()) {
1939 Wrapper srcWrapper = Wrapper.forBasicType(rtype);
1940 Wrapper dstWrapper = srcWrapper.isSubwordOrInt() ? Wrapper.INT : srcWrapper; // widen subword to int
1941 // boolean casts not allowed
1942 emitPrimCast(srcWrapper, dstWrapper);
1943 emitBoxing(dstWrapper);
1944 }
1945
1946 // If the return type is void we return a null reference.
1947 if (rtype == void.class) {
1948 mv.visitInsn(Opcodes.ACONST_NULL);
1949 }
1950 emitReturnInsn(L_TYPE); // NOTE: NamedFunction invokers always return a reference value.
1951
1952 methodEpilogue();
1953 clinit(cw, className, classData);
1954 bogusMethod(dstType);
1955
1956 final byte[] classFile = cw.toByteArray();
1957 maybeDump(classFile);
1958 return classFile;
1959 }
1960
1961 /**
1962 * Emit a bogus method that just loads some string constants. This is to get the constants into the constant pool
1963 * for debugging purposes.
1964 */
1965 private void bogusMethod(Object os) {
1966 if (DUMP_CLASS_FILES) {
1967 mv = cw.visitMethod(Opcodes.ACC_STATIC, "dummy", "()V", null, null);
1968 mv.visitLdcInsn(os.toString());
1969 mv.visitInsn(Opcodes.POP);
1970 mv.visitInsn(Opcodes.RETURN);
1971 mv.visitMaxs(0, 0);
1972 mv.visitEnd();
1973 }
1974 }
1975 }