1 /*
2 * Copyright (c) 2012, 2016, 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.Label;
30 import jdk.internal.org.objectweb.asm.MethodVisitor;
31 import jdk.internal.org.objectweb.asm.Opcodes;
32 import jdk.internal.org.objectweb.asm.Type;
33 import sun.invoke.util.VerifyAccess;
34 import sun.invoke.util.VerifyType;
35 import sun.invoke.util.Wrapper;
36 import sun.reflect.misc.ReflectUtil;
37
38 import java.io.File;
39 import java.io.FileOutputStream;
40 import java.io.IOException;
41 import java.lang.reflect.Modifier;
42 import java.util.ArrayList;
43 import java.util.Arrays;
44 import java.util.HashMap;
45 import java.util.stream.Stream;
46
47 import static java.lang.invoke.LambdaForm.BasicType;
48 import static java.lang.invoke.LambdaForm.BasicType.*;
49 import static java.lang.invoke.LambdaForm.*;
50 import static java.lang.invoke.MethodHandleNatives.Constants.*;
51 import static java.lang.invoke.MethodHandleStatics.*;
52
53 /**
54 * Code generation backend for LambdaForm.
55 * <p>
56 * @author John Rose, JSR 292 EG
57 */
58 class InvokerBytecodeGenerator {
59 /** Define class names for convenience. */
60 private static final String MH = "java/lang/invoke/MethodHandle";
61 private static final String MHI = "java/lang/invoke/MethodHandleImpl";
62 private static final String LF = "java/lang/invoke/LambdaForm";
63 private static final String LFN = "java/lang/invoke/LambdaForm$Name";
64 private static final String CLS = "java/lang/Class";
65 private static final String OBJ = "java/lang/Object";
66 private static final String OBJARY = "[Ljava/lang/Object;";
67
68 private static final String LOOP_CLAUSES = MHI + "$LoopClauses";
69 private static final String MHARY2 = "[[L" + MH + ";";
70
71 private static final String LF_SIG = "L" + LF + ";";
72 private static final String LFN_SIG = "L" + LFN + ";";
73 private static final String LL_SIG = "(L" + OBJ + ";)L" + OBJ + ";";
74 private static final String LLV_SIG = "(L" + OBJ + ";L" + OBJ + ";)V";
75 private static final String CLASS_PREFIX = LF + "$";
76 private static final String SOURCE_PREFIX = "LambdaForm$";
77
78 /** Name of its super class*/
79 static final String INVOKER_SUPER_NAME = OBJ;
80
81 /** Name of new class */
82 private final String className;
83
84 private final LambdaForm lambdaForm;
85 private final String invokerName;
86 private final MethodType invokerType;
87
88 /** Info about local variables in compiled lambda form */
89 private int[] localsMap; // index
90 private Class<?>[] localClasses; // type
91
92 /** ASM bytecode generation. */
93 private ClassWriter cw;
94 private MethodVisitor mv;
95
96 private static final MemberName.Factory MEMBERNAME_FACTORY = MemberName.getFactory();
97 private static final Class<?> HOST_CLASS = LambdaForm.class;
98
99 /** Main constructor; other constructors delegate to this one. */
100 private InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize,
101 String className, String invokerName, MethodType invokerType) {
102 int p = invokerName.indexOf('.');
103 if (p > -1) {
104 className = invokerName.substring(0, p);
105 invokerName = invokerName.substring(p + 1);
106 }
107 if (DUMP_CLASS_FILES) {
108 className = makeDumpableClassName(className);
109 }
110 this.className = className;
111 this.lambdaForm = lambdaForm;
112 this.invokerName = invokerName;
113 this.invokerType = invokerType;
114 this.localsMap = new int[localsMapSize+1]; // last entry of localsMap is count of allocated local slots
115 this.localClasses = new Class<?>[localsMapSize+1];
116 }
117
118 /** For generating LambdaForm interpreter entry points. */
119 private InvokerBytecodeGenerator(String className, String invokerName, MethodType invokerType) {
120 this(null, invokerType.parameterCount(),
121 className, invokerName, invokerType);
122 // Create an array to map name indexes to locals indexes.
123 for (int i = 0; i < localsMap.length; i++) {
124 localsMap[i] = invokerType.parameterSlotCount() - invokerType.parameterSlotDepth(i);
125 }
126 }
127
128 /** For generating customized code for a single LambdaForm. */
129 private InvokerBytecodeGenerator(String className, LambdaForm form, MethodType invokerType) {
130 this(className, form.lambdaName(), form, invokerType);
131 }
132
133 /** For generating customized code for a single LambdaForm. */
134 InvokerBytecodeGenerator(String className, String invokerName,
135 LambdaForm form, MethodType invokerType) {
136 this(form, form.names.length,
137 className, invokerName, invokerType);
138 // Create an array to map name indexes to locals indexes.
139 Name[] names = form.names;
140 for (int i = 0, index = 0; i < localsMap.length; i++) {
141 localsMap[i] = index;
142 if (i < names.length) {
143 BasicType type = names[i].type();
144 index += type.basicTypeSlots();
145 }
146 }
147 }
148
149 /** instance counters for dumped classes */
150 private static final HashMap<String,Integer> DUMP_CLASS_FILES_COUNTERS;
151 /** debugging flag for saving generated class files */
152 private static final File DUMP_CLASS_FILES_DIR;
153
154 static {
155 if (DUMP_CLASS_FILES) {
156 DUMP_CLASS_FILES_COUNTERS = new HashMap<>();
157 try {
158 File dumpDir = new File("DUMP_CLASS_FILES");
159 if (!dumpDir.exists()) {
160 dumpDir.mkdirs();
161 }
162 DUMP_CLASS_FILES_DIR = dumpDir;
163 System.out.println("Dumping class files to "+DUMP_CLASS_FILES_DIR+"/...");
164 } catch (Exception e) {
165 throw newInternalError(e);
166 }
167 } else {
168 DUMP_CLASS_FILES_COUNTERS = null;
169 DUMP_CLASS_FILES_DIR = null;
170 }
171 }
172
173 private void maybeDump(final byte[] classFile) {
174 if (DUMP_CLASS_FILES) {
175 maybeDump(CLASS_PREFIX + className, classFile);
176 }
177 }
178
179 // Also used from BoundMethodHandle
180 static void maybeDump(final String className, final byte[] classFile) {
181 if (DUMP_CLASS_FILES) {
182 java.security.AccessController.doPrivileged(
183 new java.security.PrivilegedAction<>() {
184 public Void run() {
185 try {
186 String dumpName = className.replace('.','/');
187 File dumpFile = new File(DUMP_CLASS_FILES_DIR, dumpName+".class");
188 System.out.println("dump: " + dumpFile);
189 dumpFile.getParentFile().mkdirs();
190 FileOutputStream file = new FileOutputStream(dumpFile);
191 file.write(classFile);
192 file.close();
193 return null;
194 } catch (IOException ex) {
195 throw newInternalError(ex);
196 }
197 }
198 });
199 }
200 }
201
202 private static String makeDumpableClassName(String className) {
203 Integer ctr;
204 synchronized (DUMP_CLASS_FILES_COUNTERS) {
205 ctr = DUMP_CLASS_FILES_COUNTERS.get(className);
206 if (ctr == null) ctr = 0;
207 DUMP_CLASS_FILES_COUNTERS.put(className, ctr+1);
208 }
209 String sfx = ctr.toString();
210 while (sfx.length() < 3)
211 sfx = "0"+sfx;
212 className += sfx;
213 return className;
214 }
215
216 class CpPatch {
217 final int index;
218 final Object value;
219 CpPatch(int index, Object value) {
220 this.index = index;
221 this.value = value;
222 }
223 public String toString() {
224 return "CpPatch/index="+index+",value="+value;
225 }
226 }
227
228 private final ArrayList<CpPatch> cpPatches = new ArrayList<>();
229
230 private int cph = 0; // for counting constant placeholders
231
232 String constantPlaceholder(Object arg) {
233 String cpPlaceholder = "CONSTANT_PLACEHOLDER_" + cph++;
234 if (DUMP_CLASS_FILES) cpPlaceholder += " <<" + debugString(arg) + ">>";
235 // TODO check if arg is already in the constant pool
236 // insert placeholder in CP and remember the patch
237 int index = cw.newConst((Object) cpPlaceholder);
238 cpPatches.add(new CpPatch(index, arg));
239 return cpPlaceholder;
240 }
241
242 Object[] cpPatches(byte[] classFile) {
243 int size = getConstantPoolSize(classFile);
244 Object[] res = new Object[size];
245 for (CpPatch p : cpPatches) {
246 if (p.index >= size)
247 throw new InternalError("in cpool["+size+"]: "+p+"\n"+Arrays.toString(Arrays.copyOf(classFile, 20)));
248 res[p.index] = p.value;
249 }
250 return res;
251 }
252
253 private static String debugString(Object arg) {
254 if (arg instanceof MethodHandle) {
255 MethodHandle mh = (MethodHandle) arg;
256 MemberName member = mh.internalMemberName();
257 if (member != null)
258 return member.toString();
259 return mh.debugString();
260 }
261 return arg.toString();
262 }
263
264 /**
265 * Extract the number of constant pool entries from a given class file.
266 *
267 * @param classFile the bytes of the class file in question.
268 * @return the number of entries in the constant pool.
269 */
270 private static int getConstantPoolSize(byte[] classFile) {
271 // The first few bytes:
272 // u4 magic;
273 // u2 minor_version;
274 // u2 major_version;
275 // u2 constant_pool_count;
276 return ((classFile[8] & 0xFF) << 8) | (classFile[9] & 0xFF);
277 }
278
279 /**
280 * Extract the MemberName of a newly-defined method.
281 */
282 private MemberName loadMethod(byte[] classFile) {
283 Class<?> invokerClass = loadAndInitializeInvokerClass(classFile, cpPatches(classFile));
284 return resolveInvokerMember(invokerClass, invokerName, invokerType);
285 }
286
287 /**
288 * Define a given class as anonymous class in the runtime system.
289 */
290 private static Class<?> loadAndInitializeInvokerClass(byte[] classBytes, Object[] patches) {
291 Class<?> invokerClass = UNSAFE.defineAnonymousClass(HOST_CLASS, classBytes, patches);
292 UNSAFE.ensureClassInitialized(invokerClass); // Make sure the class is initialized; VM might complain.
293 return invokerClass;
294 }
295
296 private static MemberName resolveInvokerMember(Class<?> invokerClass, String name, MethodType type) {
297 MemberName member = new MemberName(invokerClass, name, type, REF_invokeStatic);
298 try {
299 member = MEMBERNAME_FACTORY.resolveOrFail(REF_invokeStatic, member, HOST_CLASS, ReflectiveOperationException.class);
300 } catch (ReflectiveOperationException e) {
301 throw newInternalError(e);
302 }
303 return member;
304 }
305
306 /**
307 * Set up class file generation.
308 */
309 private ClassWriter classFilePrologue() {
310 final int NOT_ACC_PUBLIC = 0; // not ACC_PUBLIC
311 cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
312 cw.visit(Opcodes.V1_8, NOT_ACC_PUBLIC + Opcodes.ACC_FINAL + Opcodes.ACC_SUPER,
313 CLASS_PREFIX + className, null, INVOKER_SUPER_NAME, null);
314 cw.visitSource(SOURCE_PREFIX + className, null);
315 return cw;
316 }
317
318 private void methodPrologue() {
319 String invokerDesc = invokerType.toMethodDescriptorString();
320 mv = cw.visitMethod(Opcodes.ACC_STATIC, invokerName, invokerDesc, null, null);
321 }
322
323 /**
324 * Tear down class file generation.
325 */
326 private void methodEpilogue() {
327 mv.visitMaxs(0, 0);
328 mv.visitEnd();
329 }
330
331 /*
332 * Low-level emit helpers.
333 */
334 private void emitConst(Object con) {
335 if (con == null) {
336 mv.visitInsn(Opcodes.ACONST_NULL);
337 return;
338 }
339 if (con instanceof Integer) {
340 emitIconstInsn((int) con);
341 return;
342 }
343 if (con instanceof Byte) {
344 emitIconstInsn((byte)con);
345 return;
346 }
347 if (con instanceof Short) {
348 emitIconstInsn((short)con);
349 return;
350 }
351 if (con instanceof Character) {
352 emitIconstInsn((char)con);
353 return;
354 }
355 if (con instanceof Long) {
356 long x = (long) con;
357 short sx = (short)x;
358 if (x == sx) {
359 if (sx >= 0 && sx <= 1) {
360 mv.visitInsn(Opcodes.LCONST_0 + (int) sx);
361 } else {
362 emitIconstInsn((int) x);
363 mv.visitInsn(Opcodes.I2L);
364 }
365 return;
366 }
367 }
368 if (con instanceof Float) {
369 float x = (float) con;
370 short sx = (short)x;
371 if (x == sx) {
372 if (sx >= 0 && sx <= 2) {
373 mv.visitInsn(Opcodes.FCONST_0 + (int) sx);
374 } else {
375 emitIconstInsn((int) x);
376 mv.visitInsn(Opcodes.I2F);
377 }
378 return;
379 }
380 }
381 if (con instanceof Double) {
382 double x = (double) con;
383 short sx = (short)x;
384 if (x == sx) {
385 if (sx >= 0 && sx <= 1) {
386 mv.visitInsn(Opcodes.DCONST_0 + (int) sx);
387 } else {
388 emitIconstInsn((int) x);
389 mv.visitInsn(Opcodes.I2D);
390 }
391 return;
392 }
393 }
394 if (con instanceof Boolean) {
395 emitIconstInsn((boolean) con ? 1 : 0);
396 return;
397 }
398 // fall through:
399 mv.visitLdcInsn(con);
400 }
401
402 private void emitIconstInsn(final int cst) {
403 if (cst >= -1 && cst <= 5) {
404 mv.visitInsn(Opcodes.ICONST_0 + cst);
405 } else if (cst >= Byte.MIN_VALUE && cst <= Byte.MAX_VALUE) {
406 mv.visitIntInsn(Opcodes.BIPUSH, cst);
407 } else if (cst >= Short.MIN_VALUE && cst <= Short.MAX_VALUE) {
408 mv.visitIntInsn(Opcodes.SIPUSH, cst);
409 } else {
410 mv.visitLdcInsn(cst);
411 }
412 }
413
414 /*
415 * NOTE: These load/store methods use the localsMap to find the correct index!
416 */
417 private void emitLoadInsn(BasicType type, int index) {
418 int opcode = loadInsnOpcode(type);
419 mv.visitVarInsn(opcode, localsMap[index]);
420 }
421
422 private int loadInsnOpcode(BasicType type) throws InternalError {
423 switch (type) {
424 case I_TYPE: return Opcodes.ILOAD;
425 case J_TYPE: return Opcodes.LLOAD;
426 case F_TYPE: return Opcodes.FLOAD;
427 case D_TYPE: return Opcodes.DLOAD;
428 case L_TYPE: return Opcodes.ALOAD;
429 default:
430 throw new InternalError("unknown type: " + type);
431 }
432 }
433 private void emitAloadInsn(int index) {
434 emitLoadInsn(L_TYPE, index);
435 }
436
437 private void emitStoreInsn(BasicType type, int index) {
438 int opcode = storeInsnOpcode(type);
439 mv.visitVarInsn(opcode, localsMap[index]);
440 }
441
442 private int storeInsnOpcode(BasicType type) throws InternalError {
443 switch (type) {
444 case I_TYPE: return Opcodes.ISTORE;
445 case J_TYPE: return Opcodes.LSTORE;
446 case F_TYPE: return Opcodes.FSTORE;
447 case D_TYPE: return Opcodes.DSTORE;
448 case L_TYPE: return Opcodes.ASTORE;
449 default:
450 throw new InternalError("unknown type: " + type);
451 }
452 }
453 private void emitAstoreInsn(int index) {
454 emitStoreInsn(L_TYPE, index);
455 }
456
457 private byte arrayTypeCode(Wrapper elementType) {
458 switch (elementType) {
459 case BOOLEAN: return Opcodes.T_BOOLEAN;
460 case BYTE: return Opcodes.T_BYTE;
461 case CHAR: return Opcodes.T_CHAR;
462 case SHORT: return Opcodes.T_SHORT;
463 case INT: return Opcodes.T_INT;
464 case LONG: return Opcodes.T_LONG;
465 case FLOAT: return Opcodes.T_FLOAT;
466 case DOUBLE: return Opcodes.T_DOUBLE;
467 case OBJECT: return 0; // in place of Opcodes.T_OBJECT
468 default: throw new InternalError();
469 }
470 }
471
472 private int arrayInsnOpcode(byte tcode, int aaop) throws InternalError {
473 assert(aaop == Opcodes.AASTORE || aaop == Opcodes.AALOAD);
474 int xas;
475 switch (tcode) {
476 case Opcodes.T_BOOLEAN: xas = Opcodes.BASTORE; break;
477 case Opcodes.T_BYTE: xas = Opcodes.BASTORE; break;
478 case Opcodes.T_CHAR: xas = Opcodes.CASTORE; break;
479 case Opcodes.T_SHORT: xas = Opcodes.SASTORE; break;
480 case Opcodes.T_INT: xas = Opcodes.IASTORE; break;
481 case Opcodes.T_LONG: xas = Opcodes.LASTORE; break;
482 case Opcodes.T_FLOAT: xas = Opcodes.FASTORE; break;
483 case Opcodes.T_DOUBLE: xas = Opcodes.DASTORE; break;
484 case 0: xas = Opcodes.AASTORE; break;
485 default: throw new InternalError();
486 }
487 return xas - Opcodes.AASTORE + aaop;
488 }
489
490 /**
491 * Emit a boxing call.
492 *
493 * @param wrapper primitive type class to box.
494 */
495 private void emitBoxing(Wrapper wrapper) {
496 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
497 String name = "valueOf";
498 String desc = "(" + wrapper.basicTypeChar() + ")L" + owner + ";";
499 mv.visitMethodInsn(Opcodes.INVOKESTATIC, owner, name, desc, false);
500 }
501
502 /**
503 * Emit an unboxing call (plus preceding checkcast).
504 *
505 * @param wrapper wrapper type class to unbox.
506 */
507 private void emitUnboxing(Wrapper wrapper) {
508 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
509 String name = wrapper.primitiveSimpleName() + "Value";
510 String desc = "()" + wrapper.basicTypeChar();
511 emitReferenceCast(wrapper.wrapperType(), null);
512 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, owner, name, desc, false);
513 }
514
515 /**
516 * Emit an implicit conversion for an argument which must be of the given pclass.
517 * This is usually a no-op, except when pclass is a subword type or a reference other than Object or an interface.
518 *
519 * @param ptype type of value present on stack
520 * @param pclass type of value required on stack
521 * @param arg compile-time representation of value on stack (Node, constant) or null if none
522 */
523 private void emitImplicitConversion(BasicType ptype, Class<?> pclass, Object arg) {
524 assert(basicType(pclass) == ptype); // boxing/unboxing handled by caller
525 if (pclass == ptype.basicTypeClass() && ptype != L_TYPE)
526 return; // nothing to do
527 switch (ptype) {
528 case L_TYPE:
529 if (VerifyType.isNullConversion(Object.class, pclass, false)) {
530 if (PROFILE_LEVEL > 0)
531 emitReferenceCast(Object.class, arg);
532 return;
533 }
534 emitReferenceCast(pclass, arg);
535 return;
536 case I_TYPE:
537 if (!VerifyType.isNullConversion(int.class, pclass, false))
538 emitPrimCast(ptype.basicTypeWrapper(), Wrapper.forPrimitiveType(pclass));
539 return;
540 }
541 throw newInternalError("bad implicit conversion: tc="+ptype+": "+pclass);
542 }
543
544 /** Update localClasses type map. Return true if the information is already present. */
545 private boolean assertStaticType(Class<?> cls, Name n) {
546 int local = n.index();
547 Class<?> aclass = localClasses[local];
548 if (aclass != null && (aclass == cls || cls.isAssignableFrom(aclass))) {
549 return true; // type info is already present
550 } else if (aclass == null || aclass.isAssignableFrom(cls)) {
551 localClasses[local] = cls; // type info can be improved
552 }
553 return false;
554 }
555
556 private void emitReferenceCast(Class<?> cls, Object arg) {
557 Name writeBack = null; // local to write back result
558 if (arg instanceof Name) {
559 Name n = (Name) arg;
560 if (lambdaForm.useCount(n) > 1) {
561 // This guy gets used more than once.
562 writeBack = n;
563 if (assertStaticType(cls, n)) {
564 return; // this cast was already performed
565 }
566 }
567 }
568 if (isStaticallyNameable(cls)) {
569 String sig = getInternalName(cls);
570 mv.visitTypeInsn(Opcodes.CHECKCAST, sig);
571 } else {
572 mv.visitLdcInsn(constantPlaceholder(cls));
573 mv.visitTypeInsn(Opcodes.CHECKCAST, CLS);
574 mv.visitInsn(Opcodes.SWAP);
575 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, CLS, "cast", LL_SIG, false);
576 if (Object[].class.isAssignableFrom(cls))
577 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJARY);
578 else if (PROFILE_LEVEL > 0)
579 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJ);
580 }
581 if (writeBack != null) {
582 mv.visitInsn(Opcodes.DUP);
583 emitAstoreInsn(writeBack.index());
584 }
585 }
586
587 /**
588 * Emits an actual return instruction conforming to the given return type.
589 */
590 private void emitReturnInsn(BasicType type) {
591 int opcode;
592 switch (type) {
593 case I_TYPE: opcode = Opcodes.IRETURN; break;
594 case J_TYPE: opcode = Opcodes.LRETURN; break;
595 case F_TYPE: opcode = Opcodes.FRETURN; break;
596 case D_TYPE: opcode = Opcodes.DRETURN; break;
597 case L_TYPE: opcode = Opcodes.ARETURN; break;
598 case V_TYPE: opcode = Opcodes.RETURN; break;
599 default:
600 throw new InternalError("unknown return type: " + type);
601 }
602 mv.visitInsn(opcode);
603 }
604
605 private static String getInternalName(Class<?> c) {
606 if (c == Object.class) return OBJ;
607 else if (c == Object[].class) return OBJARY;
608 else if (c == Class.class) return CLS;
609 else if (c == MethodHandle.class) return MH;
610 assert(VerifyAccess.isTypeVisible(c, Object.class)) : c.getName();
611 return c.getName().replace('.', '/');
612 }
613
614 private static MemberName resolveFrom(String name, MethodType type, Class<?> holder) {
615 MemberName member = new MemberName(holder, name, type, REF_invokeStatic);
616 MemberName resolvedMember = MemberName.getFactory().resolveOrNull(REF_invokeStatic, member, holder);
617 if (TRACE_RESOLVE) {
618 System.out.println("[LF_RESOLVE] " + holder.getName() + " " + name + " " +
619 shortenSignature(basicTypeSignature(type)) + (resolvedMember != null ? " (success)" : " (fail)") );
620 }
621 return resolvedMember;
622 }
623
624 private static MemberName lookupPregenerated(LambdaForm form, MethodType invokerType) {
625 if (form.customized != null) {
626 // No pre-generated version for customized LF
627 return null;
628 }
629 String name = form.kind.methodName;
630 switch (form.kind) {
631 case BOUND_REINVOKER: {
632 name = name + "_" + BoundMethodHandle.speciesDataFor(form).key();
633 return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class);
634 }
635 case DELEGATE: return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class);
636 case ZERO: // fall-through
637 case IDENTITY: {
638 name = name + "_" + form.returnType().basicTypeChar();
639 return resolveFrom(name, invokerType, LambdaForm.Holder.class);
640 }
641 case EXACT_INVOKER: // fall-through
642 case EXACT_LINKER: // fall-through
643 case GENERIC_INVOKER: // fall-through
644 case GENERIC_LINKER: return resolveFrom(name, invokerType.basicType(), Invokers.Holder.class);
645 case GET_OBJECT: // fall-through
646 case GET_BOOLEAN: // fall-through
647 case GET_BYTE: // fall-through
648 case GET_CHAR: // fall-through
649 case GET_SHORT: // fall-through
650 case GET_INT: // fall-through
651 case GET_LONG: // fall-through
652 case GET_FLOAT: // fall-through
653 case GET_DOUBLE: // fall-through
654 case PUT_OBJECT: // fall-through
655 case PUT_BOOLEAN: // fall-through
656 case PUT_BYTE: // fall-through
657 case PUT_CHAR: // fall-through
658 case PUT_SHORT: // fall-through
659 case PUT_INT: // fall-through
660 case PUT_LONG: // fall-through
661 case PUT_FLOAT: // fall-through
662 case PUT_DOUBLE: // fall-through
663 case DIRECT_INVOKE_INTERFACE: // fall-through
664 case DIRECT_INVOKE_SPECIAL: // fall-through
665 case DIRECT_INVOKE_STATIC: // fall-through
666 case DIRECT_INVOKE_STATIC_INIT: // fall-through
667 case DIRECT_INVOKE_VIRTUAL: return resolveFrom(name, invokerType, DirectMethodHandle.Holder.class);
668 }
669 return null;
670 }
671
672 /**
673 * Generate customized bytecode for a given LambdaForm.
674 */
675 static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) {
676 MemberName pregenerated = lookupPregenerated(form, invokerType);
677 if (pregenerated != null) return pregenerated; // pre-generated bytecode
678
679 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("MH", form, invokerType);
680 return g.loadMethod(g.generateCustomizedCodeBytes());
681 }
682
683 /** Generates code to check that actual receiver and LambdaForm matches */
684 private boolean checkActualReceiver() {
685 // Expects MethodHandle on the stack and actual receiver MethodHandle in slot #0
686 mv.visitInsn(Opcodes.DUP);
687 mv.visitVarInsn(Opcodes.ALOAD, localsMap[0]);
688 mv.visitMethodInsn(Opcodes.INVOKESTATIC, MHI, "assertSame", LLV_SIG, false);
689 return true;
690 }
691
692 static String className(String cn) {
693 assert checkClassName(cn): "Class not found: " + cn;
694 return cn;
695 }
696
697 static boolean checkClassName(String cn) {
698 Type tp = Type.getType(cn);
699 // additional sanity so only valid "L;" descriptors work
700 if (tp.getSort() != Type.OBJECT) {
701 return false;
702 }
703 try {
704 Class<?> c = Class.forName(tp.getClassName(), false, null);
705 return true;
706 } catch (ClassNotFoundException e) {
707 return false;
708 }
709 }
710
711 static final String LF_HIDDEN_SIG = className("Ljava/lang/invoke/LambdaForm$Hidden;");
712 static final String LF_COMPILED_SIG = className("Ljava/lang/invoke/LambdaForm$Compiled;");
713 static final String FORCEINLINE_SIG = className("Ljdk/internal/vm/annotation/ForceInline;");
714 static final String DONTINLINE_SIG = className("Ljdk/internal/vm/annotation/DontInline;");
715 static final String INJECTEDPROFILE_SIG = className("Ljava/lang/invoke/InjectedProfile;");
716
717 /**
718 * Generate an invoker method for the passed {@link LambdaForm}.
719 */
720 private byte[] generateCustomizedCodeBytes() {
721 classFilePrologue();
722 addMethod();
723 bogusMethod(lambdaForm);
724
725 final byte[] classFile = toByteArray();
726 maybeDump(classFile);
727 return classFile;
728 }
729
730 void setClassWriter(ClassWriter cw) {
731 this.cw = cw;
732 }
733
734 void addMethod() {
735 methodPrologue();
736
737 // Suppress this method in backtraces displayed to the user.
738 mv.visitAnnotation(LF_HIDDEN_SIG, true);
739
740 // Mark this method as a compiled LambdaForm
741 mv.visitAnnotation(LF_COMPILED_SIG, true);
742
743 if (lambdaForm.forceInline) {
744 // Force inlining of this invoker method.
745 mv.visitAnnotation(FORCEINLINE_SIG, true);
746 } else {
747 mv.visitAnnotation(DONTINLINE_SIG, true);
748 }
749
750 constantPlaceholder(lambdaForm); // keep LambdaForm instance & its compiled form lifetime tightly coupled.
751
752 if (lambdaForm.customized != null) {
753 // Since LambdaForm is customized for a particular MethodHandle, it's safe to substitute
754 // receiver MethodHandle (at slot #0) with an embedded constant and use it instead.
755 // It enables more efficient code generation in some situations, since embedded constants
756 // are compile-time constants for JIT compiler.
757 mv.visitLdcInsn(constantPlaceholder(lambdaForm.customized));
758 mv.visitTypeInsn(Opcodes.CHECKCAST, MH);
759 assert(checkActualReceiver()); // expects MethodHandle on top of the stack
760 mv.visitVarInsn(Opcodes.ASTORE, localsMap[0]);
761 }
762
763 // iterate over the form's names, generating bytecode instructions for each
764 // start iterating at the first name following the arguments
765 Name onStack = null;
766 for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) {
767 Name name = lambdaForm.names[i];
768
769 emitStoreResult(onStack);
770 onStack = name; // unless otherwise modified below
771 MethodHandleImpl.Intrinsic intr = name.function.intrinsicName();
772 switch (intr) {
773 case SELECT_ALTERNATIVE:
774 assert lambdaForm.isSelectAlternative(i);
775 if (PROFILE_GWT) {
776 assert(name.arguments[0] instanceof Name &&
777 ((Name)name.arguments[0]).refersTo(MethodHandleImpl.class, "profileBoolean"));
778 mv.visitAnnotation(INJECTEDPROFILE_SIG, true);
779 }
780 onStack = emitSelectAlternative(name, lambdaForm.names[i+1]);
781 i++; // skip MH.invokeBasic of the selectAlternative result
782 continue;
783 case GUARD_WITH_CATCH:
784 assert lambdaForm.isGuardWithCatch(i);
785 onStack = emitGuardWithCatch(i);
786 i += 2; // jump to the end of GWC idiom
787 continue;
788 case TRY_FINALLY:
789 assert lambdaForm.isTryFinally(i);
790 onStack = emitTryFinally(i);
791 i += 2; // jump to the end of the TF idiom
792 continue;
793 case LOOP:
794 assert lambdaForm.isLoop(i);
795 onStack = emitLoop(i);
796 i += 2; // jump to the end of the LOOP idiom
797 continue;
798 case NEW_ARRAY:
799 Class<?> rtype = name.function.methodType().returnType();
800 if (isStaticallyNameable(rtype)) {
801 emitNewArray(name);
802 continue;
803 }
804 break;
805 case ARRAY_LOAD:
806 emitArrayLoad(name);
807 continue;
808 case ARRAY_STORE:
809 emitArrayStore(name);
810 continue;
811 case ARRAY_LENGTH:
812 emitArrayLength(name);
813 continue;
814 case IDENTITY:
815 assert(name.arguments.length == 1);
816 emitPushArguments(name, 0);
817 continue;
818 case ZERO:
819 assert(name.arguments.length == 0);
820 emitConst(name.type.basicTypeWrapper().zero());
821 continue;
822 case NONE:
823 // no intrinsic associated
824 break;
825 default:
826 throw newInternalError("Unknown intrinsic: "+intr);
827 }
828
829 MemberName member = name.function.member();
830 if (isStaticallyInvocable(member)) {
831 emitStaticInvoke(member, name);
832 } else {
833 emitInvoke(name);
834 }
835 }
836
837 // return statement
838 emitReturn(onStack);
839
840 methodEpilogue();
841 }
842
843 /*
844 * @throws BytecodeGenerationException if something goes wrong when
845 * generating the byte code
846 */
847 private byte[] toByteArray() {
848 try {
849 return cw.toByteArray();
850 } catch (RuntimeException e) {
851 throw new BytecodeGenerationException(e);
852 }
853 }
854
855 @SuppressWarnings("serial")
856 static final class BytecodeGenerationException extends RuntimeException {
857 BytecodeGenerationException(Exception cause) {
858 super(cause);
859 }
860 }
861
862 void emitArrayLoad(Name name) { emitArrayOp(name, Opcodes.AALOAD); }
863 void emitArrayStore(Name name) { emitArrayOp(name, Opcodes.AASTORE); }
864 void emitArrayLength(Name name) { emitArrayOp(name, Opcodes.ARRAYLENGTH); }
865
866 void emitArrayOp(Name name, int arrayOpcode) {
867 assert arrayOpcode == Opcodes.AALOAD || arrayOpcode == Opcodes.AASTORE || arrayOpcode == Opcodes.ARRAYLENGTH;
868 Class<?> elementType = name.function.methodType().parameterType(0).getComponentType();
869 assert elementType != null;
870 emitPushArguments(name, 0);
871 if (arrayOpcode != Opcodes.ARRAYLENGTH && elementType.isPrimitive()) {
872 Wrapper w = Wrapper.forPrimitiveType(elementType);
873 arrayOpcode = arrayInsnOpcode(arrayTypeCode(w), arrayOpcode);
874 }
875 mv.visitInsn(arrayOpcode);
876 }
877
878 /**
879 * Emit an invoke for the given name.
880 */
881 void emitInvoke(Name name) {
882 assert(!name.isLinkerMethodInvoke()); // should use the static path for these
883 if (true) {
884 // push receiver
885 MethodHandle target = name.function.resolvedHandle();
886 assert(target != null) : name.exprString();
887 mv.visitLdcInsn(constantPlaceholder(target));
888 emitReferenceCast(MethodHandle.class, target);
889 } else {
890 // load receiver
891 emitAloadInsn(0);
892 emitReferenceCast(MethodHandle.class, null);
893 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", LF_SIG);
894 mv.visitFieldInsn(Opcodes.GETFIELD, LF, "names", LFN_SIG);
895 // TODO more to come
896 }
897
898 // push arguments
899 emitPushArguments(name, 0);
900
901 // invocation
902 MethodType type = name.function.methodType();
903 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
904 }
905
906 private static Class<?>[] STATICALLY_INVOCABLE_PACKAGES = {
907 // Sample classes from each package we are willing to bind to statically:
908 java.lang.Object.class,
909 java.util.Arrays.class,
910 jdk.internal.misc.Unsafe.class
911 //MethodHandle.class already covered
912 };
913
914 static boolean isStaticallyInvocable(NamedFunction ... functions) {
915 for (NamedFunction nf : functions) {
916 if (!isStaticallyInvocable(nf.member())) {
917 return false;
918 }
919 }
920 return true;
921 }
922
923 static boolean isStaticallyInvocable(Name name) {
924 return isStaticallyInvocable(name.function.member());
925 }
926
927 static boolean isStaticallyInvocable(MemberName member) {
928 if (member == null) return false;
929 if (member.isConstructor()) return false;
930 Class<?> cls = member.getDeclaringClass();
931 if (cls.isArray() || cls.isPrimitive())
932 return false; // FIXME
933 if (cls.isAnonymousClass() || cls.isLocalClass())
934 return false; // inner class of some sort
935 if (cls.getClassLoader() != MethodHandle.class.getClassLoader())
936 return false; // not on BCP
937 if (ReflectUtil.isVMAnonymousClass(cls)) // FIXME: switch to supported API once it is added
938 return false;
939 MethodType mtype = member.getMethodOrFieldType();
940 if (!isStaticallyNameable(mtype.returnType()))
941 return false;
942 for (Class<?> ptype : mtype.parameterArray())
943 if (!isStaticallyNameable(ptype))
944 return false;
945 if (!member.isPrivate() && VerifyAccess.isSamePackage(MethodHandle.class, cls))
946 return true; // in java.lang.invoke package
947 if (member.isPublic() && isStaticallyNameable(cls))
948 return true;
949 return false;
950 }
951
952 static boolean isStaticallyNameable(Class<?> cls) {
953 if (cls == Object.class)
954 return true;
955 while (cls.isArray())
956 cls = cls.getComponentType();
957 if (cls.isPrimitive())
958 return true; // int[].class, for example
959 if (ReflectUtil.isVMAnonymousClass(cls)) // FIXME: switch to supported API once it is added
960 return false;
961 // could use VerifyAccess.isClassAccessible but the following is a safe approximation
962 if (cls.getClassLoader() != Object.class.getClassLoader())
963 return false;
964 if (VerifyAccess.isSamePackage(MethodHandle.class, cls))
965 return true;
966 if (!Modifier.isPublic(cls.getModifiers()))
967 return false;
968 for (Class<?> pkgcls : STATICALLY_INVOCABLE_PACKAGES) {
969 if (VerifyAccess.isSamePackage(pkgcls, cls))
970 return true;
971 }
972 return false;
973 }
974
975 void emitStaticInvoke(Name name) {
976 emitStaticInvoke(name.function.member(), name);
977 }
978
979 /**
980 * Emit an invoke for the given name, using the MemberName directly.
981 */
982 void emitStaticInvoke(MemberName member, Name name) {
983 assert(member.equals(name.function.member()));
984 Class<?> defc = member.getDeclaringClass();
985 String cname = getInternalName(defc);
986 String mname = member.getName();
987 String mtype;
988 byte refKind = member.getReferenceKind();
989 if (refKind == REF_invokeSpecial) {
990 // in order to pass the verifier, we need to convert this to invokevirtual in all cases
991 assert(member.canBeStaticallyBound()) : member;
992 refKind = REF_invokeVirtual;
993 }
994
995 assert(!(member.getDeclaringClass().isInterface() && refKind == REF_invokeVirtual));
996
997 // push arguments
998 emitPushArguments(name, 0);
999
1000 // invocation
1001 if (member.isMethod()) {
1002 mtype = member.getMethodType().toMethodDescriptorString();
1003 mv.visitMethodInsn(refKindOpcode(refKind), cname, mname, mtype,
1004 member.getDeclaringClass().isInterface());
1005 } else {
1006 mtype = MethodType.toFieldDescriptorString(member.getFieldType());
1007 mv.visitFieldInsn(refKindOpcode(refKind), cname, mname, mtype);
1008 }
1009 // Issue a type assertion for the result, so we can avoid casts later.
1010 if (name.type == L_TYPE) {
1011 Class<?> rtype = member.getInvocationType().returnType();
1012 assert(!rtype.isPrimitive());
1013 if (rtype != Object.class && !rtype.isInterface()) {
1014 assertStaticType(rtype, name);
1015 }
1016 }
1017 }
1018
1019 void emitNewArray(Name name) throws InternalError {
1020 Class<?> rtype = name.function.methodType().returnType();
1021 if (name.arguments.length == 0) {
1022 // The array will be a constant.
1023 Object emptyArray;
1024 try {
1025 emptyArray = name.function.resolvedHandle().invoke();
1026 } catch (Throwable ex) {
1027 throw uncaughtException(ex);
1028 }
1029 assert(java.lang.reflect.Array.getLength(emptyArray) == 0);
1030 assert(emptyArray.getClass() == rtype); // exact typing
1031 mv.visitLdcInsn(constantPlaceholder(emptyArray));
1032 emitReferenceCast(rtype, emptyArray);
1033 return;
1034 }
1035 Class<?> arrayElementType = rtype.getComponentType();
1036 assert(arrayElementType != null);
1037 emitIconstInsn(name.arguments.length);
1038 int xas = Opcodes.AASTORE;
1039 if (!arrayElementType.isPrimitive()) {
1040 mv.visitTypeInsn(Opcodes.ANEWARRAY, getInternalName(arrayElementType));
1041 } else {
1042 byte tc = arrayTypeCode(Wrapper.forPrimitiveType(arrayElementType));
1043 xas = arrayInsnOpcode(tc, xas);
1044 mv.visitIntInsn(Opcodes.NEWARRAY, tc);
1045 }
1046 // store arguments
1047 for (int i = 0; i < name.arguments.length; i++) {
1048 mv.visitInsn(Opcodes.DUP);
1049 emitIconstInsn(i);
1050 emitPushArgument(name, i);
1051 mv.visitInsn(xas);
1052 }
1053 // the array is left on the stack
1054 assertStaticType(rtype, name);
1055 }
1056 int refKindOpcode(byte refKind) {
1057 switch (refKind) {
1058 case REF_invokeVirtual: return Opcodes.INVOKEVIRTUAL;
1059 case REF_invokeStatic: return Opcodes.INVOKESTATIC;
1060 case REF_invokeSpecial: return Opcodes.INVOKESPECIAL;
1061 case REF_invokeInterface: return Opcodes.INVOKEINTERFACE;
1062 case REF_getField: return Opcodes.GETFIELD;
1063 case REF_putField: return Opcodes.PUTFIELD;
1064 case REF_getStatic: return Opcodes.GETSTATIC;
1065 case REF_putStatic: return Opcodes.PUTSTATIC;
1066 }
1067 throw new InternalError("refKind="+refKind);
1068 }
1069
1070 /**
1071 * Emit bytecode for the selectAlternative idiom.
1072 *
1073 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithTest):
1074 * <blockquote><pre>{@code
1075 * Lambda(a0:L,a1:I)=>{
1076 * t2:I=foo.test(a1:I);
1077 * t3:L=MethodHandleImpl.selectAlternative(t2:I,(MethodHandle(int)int),(MethodHandle(int)int));
1078 * t4:I=MethodHandle.invokeBasic(t3:L,a1:I);t4:I}
1079 * }</pre></blockquote>
1080 */
1081 private Name emitSelectAlternative(Name selectAlternativeName, Name invokeBasicName) {
1082 assert isStaticallyInvocable(invokeBasicName);
1083
1084 Name receiver = (Name) invokeBasicName.arguments[0];
1085
1086 Label L_fallback = new Label();
1087 Label L_done = new Label();
1088
1089 // load test result
1090 emitPushArgument(selectAlternativeName, 0);
1091
1092 // if_icmpne L_fallback
1093 mv.visitJumpInsn(Opcodes.IFEQ, L_fallback);
1094
1095 // invoke selectAlternativeName.arguments[1]
1096 Class<?>[] preForkClasses = localClasses.clone();
1097 emitPushArgument(selectAlternativeName, 1); // get 2nd argument of selectAlternative
1098 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
1099 emitStaticInvoke(invokeBasicName);
1100
1101 // goto L_done
1102 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1103
1104 // L_fallback:
1105 mv.visitLabel(L_fallback);
1106
1107 // invoke selectAlternativeName.arguments[2]
1108 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
1109 emitPushArgument(selectAlternativeName, 2); // get 3rd argument of selectAlternative
1110 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
1111 emitStaticInvoke(invokeBasicName);
1112
1113 // L_done:
1114 mv.visitLabel(L_done);
1115 // for now do not bother to merge typestate; just reset to the dominator state
1116 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
1117
1118 return invokeBasicName; // return what's on stack
1119 }
1120
1121 /**
1122 * Emit bytecode for the guardWithCatch idiom.
1123 *
1124 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithCatch):
1125 * <blockquote><pre>{@code
1126 * guardWithCatch=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{
1127 * t8:L=MethodHandle.invokeBasic(a4:L,a6:L,a7:L);
1128 * t9:L=MethodHandleImpl.guardWithCatch(a1:L,a2:L,a3:L,t8:L);
1129 * t10:I=MethodHandle.invokeBasic(a5:L,t9:L);t10:I}
1130 * }</pre></blockquote>
1131 *
1132 * It is compiled into bytecode equivalent of the following code:
1133 * <blockquote><pre>{@code
1134 * try {
1135 * return a1.invokeBasic(a6, a7);
1136 * } catch (Throwable e) {
1137 * if (!a2.isInstance(e)) throw e;
1138 * return a3.invokeBasic(ex, a6, a7);
1139 * }}
1140 */
1141 private Name emitGuardWithCatch(int pos) {
1142 Name args = lambdaForm.names[pos];
1143 Name invoker = lambdaForm.names[pos+1];
1144 Name result = lambdaForm.names[pos+2];
1145
1146 Label L_startBlock = new Label();
1147 Label L_endBlock = new Label();
1148 Label L_handler = new Label();
1149 Label L_done = new Label();
1150
1151 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1152 MethodType type = args.function.resolvedHandle().type()
1153 .dropParameterTypes(0,1)
1154 .changeReturnType(returnType);
1155
1156 mv.visitTryCatchBlock(L_startBlock, L_endBlock, L_handler, "java/lang/Throwable");
1157
1158 // Normal case
1159 mv.visitLabel(L_startBlock);
1160 // load target
1161 emitPushArgument(invoker, 0);
1162 emitPushArguments(args, 1); // skip 1st argument: method handle
1163 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
1164 mv.visitLabel(L_endBlock);
1165 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1166
1167 // Exceptional case
1168 mv.visitLabel(L_handler);
1169
1170 // Check exception's type
1171 mv.visitInsn(Opcodes.DUP);
1172 // load exception class
1173 emitPushArgument(invoker, 1);
1174 mv.visitInsn(Opcodes.SWAP);
1175 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Class", "isInstance", "(Ljava/lang/Object;)Z", false);
1176 Label L_rethrow = new Label();
1177 mv.visitJumpInsn(Opcodes.IFEQ, L_rethrow);
1178
1179 // Invoke catcher
1180 // load catcher
1181 emitPushArgument(invoker, 2);
1182 mv.visitInsn(Opcodes.SWAP);
1183 emitPushArguments(args, 1); // skip 1st argument: method handle
1184 MethodType catcherType = type.insertParameterTypes(0, Throwable.class);
1185 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", catcherType.basicType().toMethodDescriptorString(), false);
1186 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1187
1188 mv.visitLabel(L_rethrow);
1189 mv.visitInsn(Opcodes.ATHROW);
1190
1191 mv.visitLabel(L_done);
1192
1193 return result;
1194 }
1195
1196 /**
1197 * Emit bytecode for the tryFinally idiom.
1198 * <p>
1199 * The pattern looks like (Cf. MethodHandleImpl.makeTryFinally):
1200 * <blockquote><pre>{@code
1201 * // a0: BMH
1202 * // a1: target, a2: cleanup
1203 * // a3: box, a4: unbox
1204 * // a5 (and following): arguments
1205 * tryFinally=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L)=>{
1206 * t6:L=MethodHandle.invokeBasic(a3:L,a5:L); // box the arguments into an Object[]
1207 * t7:L=MethodHandleImpl.tryFinally(a1:L,a2:L,t6:L); // call the tryFinally executor
1208 * t8:L=MethodHandle.invokeBasic(a4:L,t7:L);t8:L} // unbox the result; return the result
1209 * }</pre></blockquote>
1210 * <p>
1211 * It is compiled into bytecode equivalent to the following code:
1212 * <blockquote><pre>{@code
1213 * Throwable t;
1214 * Object r;
1215 * try {
1216 * r = a1.invokeBasic(a5);
1217 * } catch (Throwable thrown) {
1218 * t = thrown;
1219 * throw t;
1220 * } finally {
1221 * r = a2.invokeBasic(t, r, a5);
1222 * }
1223 * return r;
1224 * }</pre></blockquote>
1225 * <p>
1226 * Specifically, the bytecode will have the following form (the stack effects are given for the beginnings of
1227 * blocks, and for the situations after executing the given instruction - the code will have a slightly different
1228 * shape if the return type is {@code void}):
1229 * <blockquote><pre>{@code
1230 * TRY: (--)
1231 * load target (-- target)
1232 * load args (-- args... target)
1233 * INVOKEVIRTUAL MethodHandle.invokeBasic (depends)
1234 * FINALLY_NORMAL: (-- r)
1235 * load cleanup (-- cleanup r)
1236 * SWAP (-- r cleanup)
1237 * ACONST_NULL (-- t r cleanup)
1238 * SWAP (-- r t cleanup)
1239 * load args (-- args... r t cleanup)
1240 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r)
1241 * GOTO DONE
1242 * CATCH: (-- t)
1243 * DUP (-- t t)
1244 * FINALLY_EXCEPTIONAL: (-- t t)
1245 * load cleanup (-- cleanup t t)
1246 * SWAP (-- t cleanup t)
1247 * load default for r (-- r t cleanup t)
1248 * load args (-- args... r t cleanup t)
1249 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r t)
1250 * POP (-- t)
1251 * ATHROW
1252 * DONE: (-- r)
1253 * }</pre></blockquote>
1254 */
1255 private Name emitTryFinally(int pos) {
1256 Name args = lambdaForm.names[pos];
1257 Name invoker = lambdaForm.names[pos+1];
1258 Name result = lambdaForm.names[pos+2];
1259
1260 Label lFrom = new Label();
1261 Label lTo = new Label();
1262 Label lCatch = new Label();
1263 Label lDone = new Label();
1264
1265 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1266 boolean isNonVoid = returnType != void.class;
1267 MethodType type = args.function.resolvedHandle().type()
1268 .dropParameterTypes(0,1)
1269 .changeReturnType(returnType);
1270 MethodType cleanupType = type.insertParameterTypes(0, Throwable.class);
1271 if (isNonVoid) {
1272 cleanupType = cleanupType.insertParameterTypes(1, returnType);
1273 }
1274 String cleanupDesc = cleanupType.basicType().toMethodDescriptorString();
1275
1276 // exception handler table
1277 mv.visitTryCatchBlock(lFrom, lTo, lCatch, "java/lang/Throwable");
1278
1279 // TRY:
1280 mv.visitLabel(lFrom);
1281 emitPushArgument(invoker, 0); // load target
1282 emitPushArguments(args, 1); // load args (skip 0: method handle)
1283 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
1284 mv.visitLabel(lTo);
1285
1286 // FINALLY_NORMAL:
1287 emitPushArgument(invoker, 1); // load cleanup
1288 if (isNonVoid) {
1289 mv.visitInsn(Opcodes.SWAP);
1290 }
1291 mv.visitInsn(Opcodes.ACONST_NULL);
1292 if (isNonVoid) {
1293 mv.visitInsn(Opcodes.SWAP);
1294 }
1295 emitPushArguments(args, 1); // load args (skip 0: method handle)
1296 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", cleanupDesc, false);
1297 mv.visitJumpInsn(Opcodes.GOTO, lDone);
1298
1299 // CATCH:
1300 mv.visitLabel(lCatch);
1301 mv.visitInsn(Opcodes.DUP);
1302
1303 // FINALLY_EXCEPTIONAL:
1304 emitPushArgument(invoker, 1); // load cleanup
1305 mv.visitInsn(Opcodes.SWAP);
1306 if (isNonVoid) {
1307 emitZero(BasicType.basicType(returnType)); // load default for result
1308 }
1309 emitPushArguments(args, 1); // load args (skip 0: method handle)
1310 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", cleanupDesc, false);
1311 if (isNonVoid) {
1312 mv.visitInsn(Opcodes.POP);
1313 }
1314 mv.visitInsn(Opcodes.ATHROW);
1315
1316 // DONE:
1317 mv.visitLabel(lDone);
1318
1319 return result;
1320 }
1321
1322 /**
1323 * Emit bytecode for the loop idiom.
1324 * <p>
1325 * The pattern looks like (Cf. MethodHandleImpl.loop):
1326 * <blockquote><pre>{@code
1327 * // a0: BMH
1328 * // a1: LoopClauses (containing an array of arrays: inits, steps, preds, finis)
1329 * // a2: box, a3: unbox
1330 * // a4 (and following): arguments
1331 * loop=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L)=>{
1332 * t5:L=MethodHandle.invokeBasic(a2:L,a4:L); // box the arguments into an Object[]
1333 * t6:L=MethodHandleImpl.loop(bt:L,a1:L,t5:L); // call the loop executor (with supplied types in bt)
1334 * t7:L=MethodHandle.invokeBasic(a3:L,t6:L);t7:L} // unbox the result; return the result
1335 * }</pre></blockquote>
1336 * <p>
1337 * It is compiled into bytecode equivalent to the code seen in {@link MethodHandleImpl#loop(BasicType[],
1338 * MethodHandleImpl.LoopClauses, Object...)}, with the difference that no arrays
1339 * will be used for local state storage. Instead, the local state will be mapped to actual stack slots.
1340 * <p>
1341 * Bytecode generation applies an unrolling scheme to enable better bytecode generation regarding local state type
1342 * handling. The generated bytecode will have the following form ({@code void} types are ignored for convenience).
1343 * Assume there are {@code C} clauses in the loop.
1344 * <blockquote><pre>{@code
1345 * PREINIT: ALOAD_1
1346 * CHECKCAST LoopClauses
1347 * GETFIELD LoopClauses.clauses
1348 * ASTORE clauseDataIndex // place the clauses 2-dimensional array on the stack
1349 * INIT: (INIT_SEQ for clause 1)
1350 * ...
1351 * (INIT_SEQ for clause C)
1352 * LOOP: (LOOP_SEQ for clause 1)
1353 * ...
1354 * (LOOP_SEQ for clause C)
1355 * GOTO LOOP
1356 * DONE: ...
1357 * }</pre></blockquote>
1358 * <p>
1359 * The {@code INIT_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has
1360 * the following shape. Assume slot {@code vx} is used to hold the state for clause {@code x}.
1361 * <blockquote><pre>{@code
1362 * INIT_SEQ_x: ALOAD clauseDataIndex
1363 * ICONST_0
1364 * AALOAD // load the inits array
1365 * ICONST x
1366 * AALOAD // load the init handle for clause x
1367 * load args
1368 * INVOKEVIRTUAL MethodHandle.invokeBasic
1369 * store vx
1370 * }</pre></blockquote>
1371 * <p>
1372 * The {@code LOOP_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has
1373 * the following shape. Again, assume slot {@code vx} is used to hold the state for clause {@code x}.
1374 * <blockquote><pre>{@code
1375 * LOOP_SEQ_x: ALOAD clauseDataIndex
1376 * ICONST_1
1377 * AALOAD // load the steps array
1378 * ICONST x
1379 * AALOAD // load the step handle for clause x
1380 * load locals
1381 * load args
1382 * INVOKEVIRTUAL MethodHandle.invokeBasic
1383 * store vx
1384 * ALOAD clauseDataIndex
1385 * ICONST_2
1386 * AALOAD // load the preds array
1387 * ICONST x
1388 * AALOAD // load the pred handle for clause x
1389 * load locals
1390 * load args
1391 * INVOKEVIRTUAL MethodHandle.invokeBasic
1392 * IFNE LOOP_SEQ_x+1 // predicate returned false -> jump to next clause
1393 * ALOAD clauseDataIndex
1394 * ICONST_3
1395 * AALOAD // load the finis array
1396 * ICONST x
1397 * AALOAD // load the fini handle for clause x
1398 * load locals
1399 * load args
1400 * INVOKEVIRTUAL MethodHandle.invokeBasic
1401 * GOTO DONE // jump beyond end of clauses to return from loop
1402 * }</pre></blockquote>
1403 */
1404 private Name emitLoop(int pos) {
1405 Name args = lambdaForm.names[pos];
1406 Name invoker = lambdaForm.names[pos+1];
1407 Name result = lambdaForm.names[pos+2];
1408
1409 // extract clause and loop-local state types
1410 // find the type info in the loop invocation
1411 BasicType[] loopClauseTypes = (BasicType[]) invoker.arguments[0];
1412 Class<?>[] loopLocalStateTypes = Stream.of(loopClauseTypes).
1413 filter(bt -> bt != BasicType.V_TYPE).map(BasicType::basicTypeClass).toArray(Class<?>[]::new);
1414 Class<?>[] localTypes = new Class<?>[loopLocalStateTypes.length + 1];
1415 localTypes[0] = MethodHandleImpl.LoopClauses.class;
1416 System.arraycopy(loopLocalStateTypes, 0, localTypes, 1, loopLocalStateTypes.length);
1417
1418 final int clauseDataIndex = extendLocalsMap(localTypes);
1419 final int firstLoopStateIndex = clauseDataIndex + 1;
1420
1421 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1422 MethodType loopType = args.function.resolvedHandle().type()
1423 .dropParameterTypes(0,1)
1424 .changeReturnType(returnType);
1425 MethodType loopHandleType = loopType.insertParameterTypes(0, loopLocalStateTypes);
1426 MethodType predType = loopHandleType.changeReturnType(boolean.class);
1427 MethodType finiType = loopHandleType;
1428
1429 final int nClauses = loopClauseTypes.length;
1430
1431 // indices to invoker arguments to load method handle arrays
1432 final int inits = 1;
1433 final int steps = 2;
1434 final int preds = 3;
1435 final int finis = 4;
1436
1437 Label lLoop = new Label();
1438 Label lDone = new Label();
1439 Label lNext;
1440
1441 // PREINIT:
1442 emitPushArgument(MethodHandleImpl.LoopClauses.class, invoker.arguments[1]);
1443 mv.visitFieldInsn(Opcodes.GETFIELD, LOOP_CLAUSES, "clauses", MHARY2);
1444 emitAstoreInsn(clauseDataIndex);
1445
1446 // INIT:
1447 for (int c = 0, state = 0; c < nClauses; ++c) {
1448 MethodType cInitType = loopType.changeReturnType(loopClauseTypes[c].basicTypeClass());
1449 emitLoopHandleInvoke(invoker, inits, c, args, false, cInitType, loopLocalStateTypes, clauseDataIndex,
1450 firstLoopStateIndex);
1451 if (cInitType.returnType() != void.class) {
1452 emitStoreInsn(BasicType.basicType(cInitType.returnType()), firstLoopStateIndex + state);
1453 ++state;
1454 }
1455 }
1456
1457 // LOOP:
1458 mv.visitLabel(lLoop);
1459
1460 for (int c = 0, state = 0; c < nClauses; ++c) {
1461 lNext = new Label();
1462
1463 MethodType stepType = loopHandleType.changeReturnType(loopClauseTypes[c].basicTypeClass());
1464 boolean isVoid = stepType.returnType() == void.class;
1465
1466 // invoke loop step
1467 emitLoopHandleInvoke(invoker, steps, c, args, true, stepType, loopLocalStateTypes, clauseDataIndex,
1468 firstLoopStateIndex);
1469 if (!isVoid) {
1470 emitStoreInsn(BasicType.basicType(stepType.returnType()), firstLoopStateIndex + state);
1471 ++state;
1472 }
1473
1474 // invoke loop predicate
1475 emitLoopHandleInvoke(invoker, preds, c, args, true, predType, loopLocalStateTypes, clauseDataIndex,
1476 firstLoopStateIndex);
1477 mv.visitJumpInsn(Opcodes.IFNE, lNext);
1478
1479 // invoke fini
1480 emitLoopHandleInvoke(invoker, finis, c, args, true, finiType, loopLocalStateTypes, clauseDataIndex,
1481 firstLoopStateIndex);
1482 mv.visitJumpInsn(Opcodes.GOTO, lDone);
1483
1484 // this is the beginning of the next loop clause
1485 mv.visitLabel(lNext);
1486 }
1487
1488 mv.visitJumpInsn(Opcodes.GOTO, lLoop);
1489
1490 // DONE:
1491 mv.visitLabel(lDone);
1492
1493 return result;
1494 }
1495
1496 private int extendLocalsMap(Class<?>[] types) {
1497 int firstSlot = localsMap.length - 1;
1498 localsMap = Arrays.copyOf(localsMap, localsMap.length + types.length);
1499 localClasses = Arrays.copyOf(localClasses, localClasses.length + types.length);
1500 System.arraycopy(types, 0, localClasses, firstSlot, types.length);
1501 int index = localsMap[firstSlot - 1] + 1;
1502 int lastSlots = 0;
1503 for (int i = 0; i < types.length; ++i) {
1504 localsMap[firstSlot + i] = index;
1505 lastSlots = BasicType.basicType(localClasses[firstSlot + i]).basicTypeSlots();
1506 index += lastSlots;
1507 }
1508 localsMap[localsMap.length - 1] = index - lastSlots;
1509 return firstSlot;
1510 }
1511
1512 private void emitLoopHandleInvoke(Name holder, int handles, int clause, Name args, boolean pushLocalState,
1513 MethodType type, Class<?>[] loopLocalStateTypes, int clauseDataSlot,
1514 int firstLoopStateSlot) {
1515 // load handle for clause
1516 emitPushClauseArray(clauseDataSlot, handles);
1517 emitIconstInsn(clause);
1518 mv.visitInsn(Opcodes.AALOAD);
1519 // load loop state (preceding the other arguments)
1520 if (pushLocalState) {
1521 for (int s = 0; s < loopLocalStateTypes.length; ++s) {
1522 emitLoadInsn(BasicType.basicType(loopLocalStateTypes[s]), firstLoopStateSlot + s);
1523 }
1524 }
1525 // load loop args (skip 0: method handle)
1526 emitPushArguments(args, 1);
1527 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.toMethodDescriptorString(), false);
1528 }
1529
1530 private void emitPushClauseArray(int clauseDataSlot, int which) {
1531 emitAloadInsn(clauseDataSlot);
1532 emitIconstInsn(which - 1);
1533 mv.visitInsn(Opcodes.AALOAD);
1534 }
1535
1536 private void emitZero(BasicType type) {
1537 switch (type) {
1538 case I_TYPE: mv.visitInsn(Opcodes.ICONST_0); break;
1539 case J_TYPE: mv.visitInsn(Opcodes.LCONST_0); break;
1540 case F_TYPE: mv.visitInsn(Opcodes.FCONST_0); break;
1541 case D_TYPE: mv.visitInsn(Opcodes.DCONST_0); break;
1542 case L_TYPE: mv.visitInsn(Opcodes.ACONST_NULL); break;
1543 default: throw new InternalError("unknown type: " + type);
1544 }
1545 }
1546
1547 private void emitPushArguments(Name args, int start) {
1548 MethodType type = args.function.methodType();
1549 for (int i = start; i < args.arguments.length; i++) {
1550 emitPushArgument(type.parameterType(i), args.arguments[i]);
1551 }
1552 }
1553
1554 private void emitPushArgument(Name name, int paramIndex) {
1555 Object arg = name.arguments[paramIndex];
1556 Class<?> ptype = name.function.methodType().parameterType(paramIndex);
1557 emitPushArgument(ptype, arg);
1558 }
1559
1560 private void emitPushArgument(Class<?> ptype, Object arg) {
1561 BasicType bptype = basicType(ptype);
1562 if (arg instanceof Name) {
1563 Name n = (Name) arg;
1564 emitLoadInsn(n.type, n.index());
1565 emitImplicitConversion(n.type, ptype, n);
1566 } else if ((arg == null || arg instanceof String) && bptype == L_TYPE) {
1567 emitConst(arg);
1568 } else {
1569 if (Wrapper.isWrapperType(arg.getClass()) && bptype != L_TYPE) {
1570 emitConst(arg);
1571 } else {
1572 mv.visitLdcInsn(constantPlaceholder(arg));
1573 emitImplicitConversion(L_TYPE, ptype, arg);
1574 }
1575 }
1576 }
1577
1578 /**
1579 * Store the name to its local, if necessary.
1580 */
1581 private void emitStoreResult(Name name) {
1582 if (name != null && name.type != V_TYPE) {
1583 // non-void: actually assign
1584 emitStoreInsn(name.type, name.index());
1585 }
1586 }
1587
1588 /**
1589 * Emits a return statement from a LF invoker. If required, the result type is cast to the correct return type.
1590 */
1591 private void emitReturn(Name onStack) {
1592 // return statement
1593 Class<?> rclass = invokerType.returnType();
1594 BasicType rtype = lambdaForm.returnType();
1595 assert(rtype == basicType(rclass)); // must agree
1596 if (rtype == V_TYPE) {
1597 // void
1598 mv.visitInsn(Opcodes.RETURN);
1599 // it doesn't matter what rclass is; the JVM will discard any value
1600 } else {
1601 LambdaForm.Name rn = lambdaForm.names[lambdaForm.result];
1602
1603 // put return value on the stack if it is not already there
1604 if (rn != onStack) {
1605 emitLoadInsn(rtype, lambdaForm.result);
1606 }
1607
1608 emitImplicitConversion(rtype, rclass, rn);
1609
1610 // generate actual return statement
1611 emitReturnInsn(rtype);
1612 }
1613 }
1614
1615 /**
1616 * Emit a type conversion bytecode casting from "from" to "to".
1617 */
1618 private void emitPrimCast(Wrapper from, Wrapper to) {
1619 // Here's how.
1620 // - indicates forbidden
1621 // <-> indicates implicit
1622 // to ----> boolean byte short char int long float double
1623 // from boolean <-> - - - - - - -
1624 // byte - <-> i2s i2c <-> i2l i2f i2d
1625 // short - i2b <-> i2c <-> i2l i2f i2d
1626 // char - i2b i2s <-> <-> i2l i2f i2d
1627 // int - i2b i2s i2c <-> i2l i2f i2d
1628 // long - l2i,i2b l2i,i2s l2i,i2c l2i <-> l2f l2d
1629 // float - f2i,i2b f2i,i2s f2i,i2c f2i f2l <-> f2d
1630 // double - d2i,i2b d2i,i2s d2i,i2c d2i d2l d2f <->
1631 if (from == to) {
1632 // no cast required, should be dead code anyway
1633 return;
1634 }
1635 if (from.isSubwordOrInt()) {
1636 // cast from {byte,short,char,int} to anything
1637 emitI2X(to);
1638 } else {
1639 // cast from {long,float,double} to anything
1640 if (to.isSubwordOrInt()) {
1641 // cast to {byte,short,char,int}
1642 emitX2I(from);
1643 if (to.bitWidth() < 32) {
1644 // targets other than int require another conversion
1645 emitI2X(to);
1646 }
1647 } else {
1648 // cast to {long,float,double} - this is verbose
1649 boolean error = false;
1650 switch (from) {
1651 case LONG:
1652 switch (to) {
1653 case FLOAT: mv.visitInsn(Opcodes.L2F); break;
1654 case DOUBLE: mv.visitInsn(Opcodes.L2D); break;
1655 default: error = true; break;
1656 }
1657 break;
1658 case FLOAT:
1659 switch (to) {
1660 case LONG : mv.visitInsn(Opcodes.F2L); break;
1661 case DOUBLE: mv.visitInsn(Opcodes.F2D); break;
1662 default: error = true; break;
1663 }
1664 break;
1665 case DOUBLE:
1666 switch (to) {
1667 case LONG : mv.visitInsn(Opcodes.D2L); break;
1668 case FLOAT: mv.visitInsn(Opcodes.D2F); break;
1669 default: error = true; break;
1670 }
1671 break;
1672 default:
1673 error = true;
1674 break;
1675 }
1676 if (error) {
1677 throw new IllegalStateException("unhandled prim cast: " + from + "2" + to);
1678 }
1679 }
1680 }
1681 }
1682
1683 private void emitI2X(Wrapper type) {
1684 switch (type) {
1685 case BYTE: mv.visitInsn(Opcodes.I2B); break;
1686 case SHORT: mv.visitInsn(Opcodes.I2S); break;
1687 case CHAR: mv.visitInsn(Opcodes.I2C); break;
1688 case INT: /* naught */ break;
1689 case LONG: mv.visitInsn(Opcodes.I2L); break;
1690 case FLOAT: mv.visitInsn(Opcodes.I2F); break;
1691 case DOUBLE: mv.visitInsn(Opcodes.I2D); break;
1692 case BOOLEAN:
1693 // For compatibility with ValueConversions and explicitCastArguments:
1694 mv.visitInsn(Opcodes.ICONST_1);
1695 mv.visitInsn(Opcodes.IAND);
1696 break;
1697 default: throw new InternalError("unknown type: " + type);
1698 }
1699 }
1700
1701 private void emitX2I(Wrapper type) {
1702 switch (type) {
1703 case LONG: mv.visitInsn(Opcodes.L2I); break;
1704 case FLOAT: mv.visitInsn(Opcodes.F2I); break;
1705 case DOUBLE: mv.visitInsn(Opcodes.D2I); break;
1706 default: throw new InternalError("unknown type: " + type);
1707 }
1708 }
1709
1710 /**
1711 * Generate bytecode for a LambdaForm.vmentry which calls interpretWithArguments.
1712 */
1713 static MemberName generateLambdaFormInterpreterEntryPoint(MethodType mt) {
1714 assert(isValidSignature(basicTypeSignature(mt)));
1715 String name = "interpret_"+basicTypeChar(mt.returnType());
1716 MethodType type = mt; // includes leading argument
1717 type = type.changeParameterType(0, MethodHandle.class);
1718 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("LFI", name, type);
1719 return g.loadMethod(g.generateLambdaFormInterpreterEntryPointBytes());
1720 }
1721
1722 private byte[] generateLambdaFormInterpreterEntryPointBytes() {
1723 classFilePrologue();
1724 methodPrologue();
1725
1726 // Suppress this method in backtraces displayed to the user.
1727 mv.visitAnnotation(LF_HIDDEN_SIG, true);
1728
1729 // Don't inline the interpreter entry.
1730 mv.visitAnnotation(DONTINLINE_SIG, true);
1731
1732 // create parameter array
1733 emitIconstInsn(invokerType.parameterCount());
1734 mv.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object");
1735
1736 // fill parameter array
1737 for (int i = 0; i < invokerType.parameterCount(); i++) {
1738 Class<?> ptype = invokerType.parameterType(i);
1739 mv.visitInsn(Opcodes.DUP);
1740 emitIconstInsn(i);
1741 emitLoadInsn(basicType(ptype), i);
1742 // box if primitive type
1743 if (ptype.isPrimitive()) {
1744 emitBoxing(Wrapper.forPrimitiveType(ptype));
1745 }
1746 mv.visitInsn(Opcodes.AASTORE);
1747 }
1748 // invoke
1749 emitAloadInsn(0);
1750 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", "Ljava/lang/invoke/LambdaForm;");
1751 mv.visitInsn(Opcodes.SWAP); // swap form and array; avoid local variable
1752 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, LF, "interpretWithArguments", "([Ljava/lang/Object;)Ljava/lang/Object;", false);
1753
1754 // maybe unbox
1755 Class<?> rtype = invokerType.returnType();
1756 if (rtype.isPrimitive() && rtype != void.class) {
1757 emitUnboxing(Wrapper.forPrimitiveType(rtype));
1758 }
1759
1760 // return statement
1761 emitReturnInsn(basicType(rtype));
1762
1763 methodEpilogue();
1764 bogusMethod(invokerType);
1765
1766 final byte[] classFile = cw.toByteArray();
1767 maybeDump(classFile);
1768 return classFile;
1769 }
1770
1771 /**
1772 * Generate bytecode for a NamedFunction invoker.
1773 */
1774 static MemberName generateNamedFunctionInvoker(MethodTypeForm typeForm) {
1775 MethodType invokerType = NamedFunction.INVOKER_METHOD_TYPE;
1776 String invokerName = "invoke_" + shortenSignature(basicTypeSignature(typeForm.erasedType()));
1777 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("NFI", invokerName, invokerType);
1778 return g.loadMethod(g.generateNamedFunctionInvokerImpl(typeForm));
1779 }
1780
1781 private byte[] generateNamedFunctionInvokerImpl(MethodTypeForm typeForm) {
1782 MethodType dstType = typeForm.erasedType();
1783 classFilePrologue();
1784 methodPrologue();
1785
1786 // Suppress this method in backtraces displayed to the user.
1787 mv.visitAnnotation(LF_HIDDEN_SIG, true);
1788
1789 // Force inlining of this invoker method.
1790 mv.visitAnnotation(FORCEINLINE_SIG, true);
1791
1792 // Load receiver
1793 emitAloadInsn(0);
1794
1795 // Load arguments from array
1796 for (int i = 0; i < dstType.parameterCount(); i++) {
1797 emitAloadInsn(1);
1798 emitIconstInsn(i);
1799 mv.visitInsn(Opcodes.AALOAD);
1800
1801 // Maybe unbox
1802 Class<?> dptype = dstType.parameterType(i);
1803 if (dptype.isPrimitive()) {
1804 Wrapper dstWrapper = Wrapper.forBasicType(dptype);
1805 Wrapper srcWrapper = dstWrapper.isSubwordOrInt() ? Wrapper.INT : dstWrapper; // narrow subword from int
1806 emitUnboxing(srcWrapper);
1807 emitPrimCast(srcWrapper, dstWrapper);
1808 }
1809 }
1810
1811 // Invoke
1812 String targetDesc = dstType.basicType().toMethodDescriptorString();
1813 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", targetDesc, false);
1814
1815 // Box primitive types
1816 Class<?> rtype = dstType.returnType();
1817 if (rtype != void.class && rtype.isPrimitive()) {
1818 Wrapper srcWrapper = Wrapper.forBasicType(rtype);
1819 Wrapper dstWrapper = srcWrapper.isSubwordOrInt() ? Wrapper.INT : srcWrapper; // widen subword to int
1820 // boolean casts not allowed
1821 emitPrimCast(srcWrapper, dstWrapper);
1822 emitBoxing(dstWrapper);
1823 }
1824
1825 // If the return type is void we return a null reference.
1826 if (rtype == void.class) {
1827 mv.visitInsn(Opcodes.ACONST_NULL);
1828 }
1829 emitReturnInsn(L_TYPE); // NOTE: NamedFunction invokers always return a reference value.
1830
1831 methodEpilogue();
1832 bogusMethod(dstType);
1833
1834 final byte[] classFile = cw.toByteArray();
1835 maybeDump(classFile);
1836 return classFile;
1837 }
1838
1839 /**
1840 * Emit a bogus method that just loads some string constants. This is to get the constants into the constant pool
1841 * for debugging purposes.
1842 */
1843 private void bogusMethod(Object... os) {
1844 if (DUMP_CLASS_FILES) {
1845 mv = cw.visitMethod(Opcodes.ACC_STATIC, "dummy", "()V", null, null);
1846 for (Object o : os) {
1847 mv.visitLdcInsn(o.toString());
1848 mv.visitInsn(Opcodes.POP);
1849 }
1850 mv.visitInsn(Opcodes.RETURN);
1851 mv.visitMaxs(0, 0);
1852 mv.visitEnd();
1853 }
1854 }
1855 }