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 java.io.*;
29 import java.util.*;
30 import java.lang.reflect.Modifier;
31
32 import jdk.internal.org.objectweb.asm.*;
33
34 import static java.lang.invoke.LambdaForm.*;
35 import static java.lang.invoke.LambdaForm.BasicType.*;
36 import static java.lang.invoke.MethodHandleStatics.*;
37 import static java.lang.invoke.MethodHandleNatives.Constants.*;
38
39 import sun.invoke.util.VerifyAccess;
40 import sun.invoke.util.VerifyType;
41 import sun.invoke.util.Wrapper;
42 import sun.reflect.misc.ReflectUtil;
43
44 /**
45 * Code generation backend for LambdaForm.
46 * <p>
47 * @author John Rose, JSR 292 EG
48 */
49 class InvokerBytecodeGenerator {
50 /** Define class names for convenience. */
51 private static final String MH = "java/lang/invoke/MethodHandle";
52 private static final String MHI = "java/lang/invoke/MethodHandleImpl";
53 private static final String LF = "java/lang/invoke/LambdaForm";
54 private static final String LFN = "java/lang/invoke/LambdaForm$Name";
55 private static final String CLS = "java/lang/Class";
56 private static final String OBJ = "java/lang/Object";
57 private static final String OBJARY = "[Ljava/lang/Object;";
58
59 private static final String LF_SIG = "L" + LF + ";";
60 private static final String LFN_SIG = "L" + LFN + ";";
61 private static final String LL_SIG = "(L" + OBJ + ";)L" + OBJ + ";";
62 private static final String LLV_SIG = "(L" + OBJ + ";L" + OBJ + ";)V";
63
64 /** Name of its super class*/
65 private static final String superName = OBJ;
66
67 /** Name of new class */
68 private final String className;
69
70 /** Name of the source file (for stack trace printing). */
71 private final String sourceFile;
72
73 private final LambdaForm lambdaForm;
74 private final String invokerName;
75 private final MethodType invokerType;
76
77 /** Info about local variables in compiled lambda form */
78 private final int[] localsMap; // index
79 private final Class<?>[] localClasses; // type
80
81 /** ASM bytecode generation. */
82 private ClassWriter cw;
83 private MethodVisitor mv;
84
85 private static final MemberName.Factory MEMBERNAME_FACTORY = MemberName.getFactory();
86 private static final Class<?> HOST_CLASS = LambdaForm.class;
87
88 /** Main constructor; other constructors delegate to this one. */
89 private InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize,
90 String className, String invokerName, MethodType invokerType) {
91 if (invokerName.contains(".")) {
92 int p = invokerName.indexOf('.');
93 className = invokerName.substring(0, p);
94 invokerName = invokerName.substring(p+1);
95 }
96 if (DUMP_CLASS_FILES) {
97 className = makeDumpableClassName(className);
98 }
99 this.className = LF + "$" + className;
100 this.sourceFile = "LambdaForm$" + className;
101 this.lambdaForm = lambdaForm;
102 this.invokerName = invokerName;
103 this.invokerType = invokerType;
104 this.localsMap = new int[localsMapSize+1];
105 // last entry of localsMap is count of allocated local slots
106 this.localClasses = new Class<?>[localsMapSize+1];
107 }
108
109 /** For generating LambdaForm interpreter entry points. */
110 private InvokerBytecodeGenerator(String className, String invokerName, MethodType invokerType) {
111 this(null, invokerType.parameterCount(),
112 className, invokerName, invokerType);
113 // Create an array to map name indexes to locals indexes.
114 for (int i = 0; i < localsMap.length; i++) {
115 localsMap[i] = invokerType.parameterSlotCount() - invokerType.parameterSlotDepth(i);
116 }
117 }
118
119 /** For generating customized code for a single LambdaForm. */
120 private InvokerBytecodeGenerator(String className, LambdaForm form, MethodType invokerType) {
121 this(form, form.names.length,
122 className, form.debugName, invokerType);
123 // Create an array to map name indexes to locals indexes.
124 Name[] names = form.names;
125 for (int i = 0, index = 0; i < localsMap.length; i++) {
126 localsMap[i] = index;
127 if (i < names.length) {
128 BasicType type = names[i].type();
129 index += type.basicTypeSlots();
130 }
131 }
132 }
133
134
135 /** instance counters for dumped classes */
136 private static final HashMap<String,Integer> DUMP_CLASS_FILES_COUNTERS;
137 /** debugging flag for saving generated class files */
138 private static final File DUMP_CLASS_FILES_DIR;
139
140 static {
141 if (DUMP_CLASS_FILES) {
142 DUMP_CLASS_FILES_COUNTERS = new HashMap<>();
143 try {
144 File dumpDir = new File("DUMP_CLASS_FILES");
145 if (!dumpDir.exists()) {
146 dumpDir.mkdirs();
147 }
148 DUMP_CLASS_FILES_DIR = dumpDir;
149 System.out.println("Dumping class files to "+DUMP_CLASS_FILES_DIR+"/...");
150 } catch (Exception e) {
151 throw newInternalError(e);
152 }
153 } else {
154 DUMP_CLASS_FILES_COUNTERS = null;
155 DUMP_CLASS_FILES_DIR = null;
156 }
157 }
158
159 static void maybeDump(final String className, final byte[] classFile) {
160 if (DUMP_CLASS_FILES) {
161 java.security.AccessController.doPrivileged(
162 new java.security.PrivilegedAction<>() {
163 public Void run() {
164 try {
165 String dumpName = className;
166 //dumpName = dumpName.replace('/', '-');
167 File dumpFile = new File(DUMP_CLASS_FILES_DIR, dumpName+".class");
168 System.out.println("dump: " + dumpFile);
169 dumpFile.getParentFile().mkdirs();
170 FileOutputStream file = new FileOutputStream(dumpFile);
171 file.write(classFile);
172 file.close();
173 return null;
174 } catch (IOException ex) {
175 throw newInternalError(ex);
176 }
177 }
178 });
179 }
180
181 }
182
183 private static String makeDumpableClassName(String className) {
184 Integer ctr;
185 synchronized (DUMP_CLASS_FILES_COUNTERS) {
186 ctr = DUMP_CLASS_FILES_COUNTERS.get(className);
187 if (ctr == null) ctr = 0;
188 DUMP_CLASS_FILES_COUNTERS.put(className, ctr+1);
189 }
190 String sfx = ctr.toString();
191 while (sfx.length() < 3)
192 sfx = "0"+sfx;
193 className += sfx;
194 return className;
195 }
196
197 class CpPatch {
198 final int index;
199 final String placeholder;
200 final Object value;
201 CpPatch(int index, String placeholder, Object value) {
202 this.index = index;
203 this.placeholder = placeholder;
204 this.value = value;
205 }
206 public String toString() {
207 return "CpPatch/index="+index+",placeholder="+placeholder+",value="+value;
208 }
209 }
210
211 Map<Object, CpPatch> cpPatches = new HashMap<>();
212
213 int cph = 0; // for counting constant placeholders
214
215 String constantPlaceholder(Object arg) {
216 String cpPlaceholder = "CONSTANT_PLACEHOLDER_" + cph++;
217 if (DUMP_CLASS_FILES) cpPlaceholder += " <<" + debugString(arg) + ">>"; // debugging aid
218 if (cpPatches.containsKey(cpPlaceholder)) {
219 throw new InternalError("observed CP placeholder twice: " + cpPlaceholder);
220 }
221 // insert placeholder in CP and remember the patch
222 int index = cw.newConst((Object) cpPlaceholder); // TODO check if already in the constant pool
223 cpPatches.put(cpPlaceholder, new CpPatch(index, cpPlaceholder, arg));
224 return cpPlaceholder;
225 }
226
227 Object[] cpPatches(byte[] classFile) {
228 int size = getConstantPoolSize(classFile);
229 Object[] res = new Object[size];
230 for (CpPatch p : cpPatches.values()) {
231 if (p.index >= size)
232 throw new InternalError("in cpool["+size+"]: "+p+"\n"+Arrays.toString(Arrays.copyOf(classFile, 20)));
233 res[p.index] = p.value;
234 }
235 return res;
236 }
237
238 private static String debugString(Object arg) {
239 if (arg instanceof MethodHandle) {
240 MethodHandle mh = (MethodHandle) arg;
241 MemberName member = mh.internalMemberName();
242 if (member != null)
243 return member.toString();
244 return mh.debugString();
245 }
246 return arg.toString();
247 }
248
249 /**
250 * Extract the number of constant pool entries from a given class file.
251 *
252 * @param classFile the bytes of the class file in question.
253 * @return the number of entries in the constant pool.
254 */
255 private static int getConstantPoolSize(byte[] classFile) {
256 // The first few bytes:
257 // u4 magic;
258 // u2 minor_version;
259 // u2 major_version;
260 // u2 constant_pool_count;
261 return ((classFile[8] & 0xFF) << 8) | (classFile[9] & 0xFF);
262 }
263
264 /**
265 * Extract the MemberName of a newly-defined method.
266 */
267 private MemberName loadMethod(byte[] classFile) {
268 Class<?> invokerClass = loadAndInitializeInvokerClass(classFile, cpPatches(classFile));
269 return resolveInvokerMember(invokerClass, invokerName, invokerType);
270 }
271
272 /**
273 * Define a given class as anonymous class in the runtime system.
274 */
275 private static Class<?> loadAndInitializeInvokerClass(byte[] classBytes, Object[] patches) {
276 Class<?> invokerClass = UNSAFE.defineAnonymousClass(HOST_CLASS, classBytes, patches);
277 UNSAFE.ensureClassInitialized(invokerClass); // Make sure the class is initialized; VM might complain.
278 return invokerClass;
279 }
280
281 private static MemberName resolveInvokerMember(Class<?> invokerClass, String name, MethodType type) {
282 MemberName member = new MemberName(invokerClass, name, type, REF_invokeStatic);
283 //System.out.println("resolveInvokerMember => "+member);
284 //for (Method m : invokerClass.getDeclaredMethods()) System.out.println(" "+m);
285 try {
286 member = MEMBERNAME_FACTORY.resolveOrFail(REF_invokeStatic, member, HOST_CLASS, ReflectiveOperationException.class);
287 } catch (ReflectiveOperationException e) {
288 throw newInternalError(e);
289 }
290 //System.out.println("resolveInvokerMember => "+member);
291 return member;
292 }
293
294 /**
295 * Set up class file generation.
296 */
297 private void classFilePrologue() {
298 final int NOT_ACC_PUBLIC = 0; // not ACC_PUBLIC
299 cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
300 cw.visit(Opcodes.V1_8, NOT_ACC_PUBLIC + Opcodes.ACC_FINAL + Opcodes.ACC_SUPER, className, null, superName, null);
301 cw.visitSource(sourceFile, null);
302
303 String invokerDesc = invokerType.toMethodDescriptorString();
304 mv = cw.visitMethod(Opcodes.ACC_STATIC, invokerName, invokerDesc, null, null);
305 }
306
307 /**
308 * Tear down class file generation.
309 */
310 private void classFileEpilogue() {
311 mv.visitMaxs(0, 0);
312 mv.visitEnd();
313 }
314
315 /*
316 * Low-level emit helpers.
317 */
318 private void emitConst(Object con) {
319 if (con == null) {
320 mv.visitInsn(Opcodes.ACONST_NULL);
321 return;
322 }
323 if (con instanceof Integer) {
324 emitIconstInsn((int) con);
325 return;
326 }
327 if (con instanceof Byte) {
328 emitIconstInsn((byte)con);
329 return;
330 }
331 if (con instanceof Short) {
332 emitIconstInsn((short)con);
333 return;
334 }
335 if (con instanceof Character) {
336 emitIconstInsn((char)con);
337 return;
338 }
339 if (con instanceof Long) {
340 long x = (long) con;
341 short sx = (short)x;
342 if (x == sx) {
343 if (sx >= 0 && sx <= 1) {
344 mv.visitInsn(Opcodes.LCONST_0 + (int) sx);
345 } else {
346 emitIconstInsn((int) x);
347 mv.visitInsn(Opcodes.I2L);
348 }
349 return;
350 }
351 }
352 if (con instanceof Float) {
353 float x = (float) con;
354 short sx = (short)x;
355 if (x == sx) {
356 if (sx >= 0 && sx <= 2) {
357 mv.visitInsn(Opcodes.FCONST_0 + (int) sx);
358 } else {
359 emitIconstInsn((int) x);
360 mv.visitInsn(Opcodes.I2F);
361 }
362 return;
363 }
364 }
365 if (con instanceof Double) {
366 double x = (double) con;
367 short sx = (short)x;
368 if (x == sx) {
369 if (sx >= 0 && sx <= 1) {
370 mv.visitInsn(Opcodes.DCONST_0 + (int) sx);
371 } else {
372 emitIconstInsn((int) x);
373 mv.visitInsn(Opcodes.I2D);
374 }
375 return;
376 }
377 }
378 if (con instanceof Boolean) {
379 emitIconstInsn((boolean) con ? 1 : 0);
380 return;
381 }
382 // fall through:
383 mv.visitLdcInsn(con);
384 }
385
386 private void emitIconstInsn(final int cst) {
387 if (cst >= -1 && cst <= 5) {
388 mv.visitInsn(Opcodes.ICONST_0 + cst);
389 } else if (cst >= Byte.MIN_VALUE && cst <= Byte.MAX_VALUE) {
390 mv.visitIntInsn(Opcodes.BIPUSH, cst);
391 } else if (cst >= Short.MIN_VALUE && cst <= Short.MAX_VALUE) {
392 mv.visitIntInsn(Opcodes.SIPUSH, cst);
393 } else {
394 mv.visitLdcInsn(cst);
395 }
396 }
397
398 /*
399 * NOTE: These load/store methods use the localsMap to find the correct index!
400 */
401 private void emitLoadInsn(BasicType type, int index) {
402 int opcode = loadInsnOpcode(type);
403 mv.visitVarInsn(opcode, localsMap[index]);
404 }
405
406 private int loadInsnOpcode(BasicType type) throws InternalError {
407 switch (type) {
408 case I_TYPE: return Opcodes.ILOAD;
409 case J_TYPE: return Opcodes.LLOAD;
410 case F_TYPE: return Opcodes.FLOAD;
411 case D_TYPE: return Opcodes.DLOAD;
412 case L_TYPE: return Opcodes.ALOAD;
413 default:
414 throw new InternalError("unknown type: " + type);
415 }
416 }
417 private void emitAloadInsn(int index) {
418 emitLoadInsn(L_TYPE, index);
419 }
420
421 private void emitStoreInsn(BasicType type, int index) {
422 int opcode = storeInsnOpcode(type);
423 mv.visitVarInsn(opcode, localsMap[index]);
424 }
425
426 private int storeInsnOpcode(BasicType type) throws InternalError {
427 switch (type) {
428 case I_TYPE: return Opcodes.ISTORE;
429 case J_TYPE: return Opcodes.LSTORE;
430 case F_TYPE: return Opcodes.FSTORE;
431 case D_TYPE: return Opcodes.DSTORE;
432 case L_TYPE: return Opcodes.ASTORE;
433 default:
434 throw new InternalError("unknown type: " + type);
435 }
436 }
437 private void emitAstoreInsn(int index) {
438 emitStoreInsn(L_TYPE, index);
439 }
440
441 private byte arrayTypeCode(Wrapper elementType) {
442 switch (elementType) {
443 case BOOLEAN: return Opcodes.T_BOOLEAN;
444 case BYTE: return Opcodes.T_BYTE;
445 case CHAR: return Opcodes.T_CHAR;
446 case SHORT: return Opcodes.T_SHORT;
447 case INT: return Opcodes.T_INT;
448 case LONG: return Opcodes.T_LONG;
449 case FLOAT: return Opcodes.T_FLOAT;
450 case DOUBLE: return Opcodes.T_DOUBLE;
451 case OBJECT: return 0; // in place of Opcodes.T_OBJECT
452 default: throw new InternalError();
453 }
454 }
455
456 private int arrayInsnOpcode(byte tcode, int aaop) throws InternalError {
457 assert(aaop == Opcodes.AASTORE || aaop == Opcodes.AALOAD);
458 int xas;
459 switch (tcode) {
460 case Opcodes.T_BOOLEAN: xas = Opcodes.BASTORE; break;
461 case Opcodes.T_BYTE: xas = Opcodes.BASTORE; break;
462 case Opcodes.T_CHAR: xas = Opcodes.CASTORE; break;
463 case Opcodes.T_SHORT: xas = Opcodes.SASTORE; break;
464 case Opcodes.T_INT: xas = Opcodes.IASTORE; break;
465 case Opcodes.T_LONG: xas = Opcodes.LASTORE; break;
466 case Opcodes.T_FLOAT: xas = Opcodes.FASTORE; break;
467 case Opcodes.T_DOUBLE: xas = Opcodes.DASTORE; break;
468 case 0: xas = Opcodes.AASTORE; break;
469 default: throw new InternalError();
470 }
471 return xas - Opcodes.AASTORE + aaop;
472 }
473
474 /**
475 * Emit a boxing call.
476 *
477 * @param wrapper primitive type class to box.
478 */
479 private void emitBoxing(Wrapper wrapper) {
480 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
481 String name = "valueOf";
482 String desc = "(" + wrapper.basicTypeChar() + ")L" + owner + ";";
483 mv.visitMethodInsn(Opcodes.INVOKESTATIC, owner, name, desc, false);
484 }
485
486 /**
487 * Emit an unboxing call (plus preceding checkcast).
488 *
489 * @param wrapper wrapper type class to unbox.
490 */
491 private void emitUnboxing(Wrapper wrapper) {
492 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
493 String name = wrapper.primitiveSimpleName() + "Value";
494 String desc = "()" + wrapper.basicTypeChar();
495 emitReferenceCast(wrapper.wrapperType(), null);
496 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, owner, name, desc, false);
497 }
498
499 /**
500 * Emit an implicit conversion for an argument which must be of the given pclass.
501 * This is usually a no-op, except when pclass is a subword type or a reference other than Object or an interface.
502 *
503 * @param ptype type of value present on stack
504 * @param pclass type of value required on stack
505 * @param arg compile-time representation of value on stack (Node, constant) or null if none
506 */
507 private void emitImplicitConversion(BasicType ptype, Class<?> pclass, Object arg) {
508 assert(basicType(pclass) == ptype); // boxing/unboxing handled by caller
509 if (pclass == ptype.basicTypeClass() && ptype != L_TYPE)
510 return; // nothing to do
511 switch (ptype) {
512 case L_TYPE:
513 if (VerifyType.isNullConversion(Object.class, pclass, false)) {
514 if (PROFILE_LEVEL > 0)
515 emitReferenceCast(Object.class, arg);
516 return;
517 }
518 emitReferenceCast(pclass, arg);
519 return;
520 case I_TYPE:
521 if (!VerifyType.isNullConversion(int.class, pclass, false))
522 emitPrimCast(ptype.basicTypeWrapper(), Wrapper.forPrimitiveType(pclass));
523 return;
524 }
525 throw newInternalError("bad implicit conversion: tc="+ptype+": "+pclass);
526 }
527
528 /** Update localClasses type map. Return true if the information is already present. */
529 private boolean assertStaticType(Class<?> cls, Name n) {
530 int local = n.index();
531 Class<?> aclass = localClasses[local];
532 if (aclass != null && (aclass == cls || cls.isAssignableFrom(aclass))) {
533 return true; // type info is already present
534 } else if (aclass == null || aclass.isAssignableFrom(cls)) {
535 localClasses[local] = cls; // type info can be improved
536 }
537 return false;
538 }
539
540 private void emitReferenceCast(Class<?> cls, Object arg) {
541 Name writeBack = null; // local to write back result
542 if (arg instanceof Name) {
543 Name n = (Name) arg;
544 if (assertStaticType(cls, n))
545 return; // this cast was already performed
546 if (lambdaForm.useCount(n) > 1) {
547 // This guy gets used more than once.
548 writeBack = n;
549 }
550 }
551 if (isStaticallyNameable(cls)) {
552 String sig = getInternalName(cls);
553 mv.visitTypeInsn(Opcodes.CHECKCAST, sig);
554 } else {
555 mv.visitLdcInsn(constantPlaceholder(cls));
556 mv.visitTypeInsn(Opcodes.CHECKCAST, CLS);
557 mv.visitInsn(Opcodes.SWAP);
558 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, CLS, "cast", LL_SIG, false);
559 if (Object[].class.isAssignableFrom(cls))
560 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJARY);
561 else if (PROFILE_LEVEL > 0)
562 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJ);
563 }
564 if (writeBack != null) {
565 mv.visitInsn(Opcodes.DUP);
566 emitAstoreInsn(writeBack.index());
567 }
568 }
569
570 /**
571 * Emits an actual return instruction conforming to the given return type.
572 */
573 private void emitReturnInsn(BasicType type) {
574 int opcode;
575 switch (type) {
576 case I_TYPE: opcode = Opcodes.IRETURN; break;
577 case J_TYPE: opcode = Opcodes.LRETURN; break;
578 case F_TYPE: opcode = Opcodes.FRETURN; break;
579 case D_TYPE: opcode = Opcodes.DRETURN; break;
580 case L_TYPE: opcode = Opcodes.ARETURN; break;
581 case V_TYPE: opcode = Opcodes.RETURN; break;
582 default:
583 throw new InternalError("unknown return type: " + type);
584 }
585 mv.visitInsn(opcode);
586 }
587
588 private static String getInternalName(Class<?> c) {
589 if (c == Object.class) return OBJ;
590 else if (c == Object[].class) return OBJARY;
591 else if (c == Class.class) return CLS;
592 else if (c == MethodHandle.class) return MH;
593 assert(VerifyAccess.isTypeVisible(c, Object.class)) : c.getName();
594 return c.getName().replace('.', '/');
595 }
596
597 /**
598 * Generate customized bytecode for a given LambdaForm.
599 */
600 static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) {
601 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("MH", form, invokerType);
602 return g.loadMethod(g.generateCustomizedCodeBytes());
603 }
604
605 /** Generates code to check that actual receiver and LambdaForm matches */
606 private boolean checkActualReceiver() {
607 // Expects MethodHandle on the stack and actual receiver MethodHandle in slot #0
608 mv.visitInsn(Opcodes.DUP);
609 mv.visitVarInsn(Opcodes.ALOAD, localsMap[0]);
610 mv.visitMethodInsn(Opcodes.INVOKESTATIC, MHI, "assertSame", LLV_SIG, false);
611 return true;
612 }
613
614 static String className(String cn) {
615 assert checkClassName(cn): "Class not found: " + cn;
616 return cn;
617 }
618
619 static boolean checkClassName(String cn) {
620 Type tp = Type.getType(cn);
621 // additional sanity so only valid "L;" descriptors work
622 if (tp.getSort() != Type.OBJECT) {
623 return false;
624 }
625 try {
626 Class<?> c = Class.forName(tp.getClassName(), false, null);
627 return true;
628 } catch (ClassNotFoundException e) {
629 return false;
630 }
631 }
632
633 static final String LF_HIDDEN_SIG = className("Ljava/lang/invoke/LambdaForm$Hidden;");
634 static final String LF_COMPILED_SIG = className("Ljava/lang/invoke/LambdaForm$Compiled;");
635 static final String FORCEINLINE_SIG = className("Ljdk/internal/vm/annotation/ForceInline;");
636 static final String DONTINLINE_SIG = className("Ljdk/internal/vm/annotation/DontInline;");
637 static final String INJECTEDPROFILE_SIG = className("Ljava/lang/invoke/InjectedProfile;");
638
639 /**
640 * Generate an invoker method for the passed {@link LambdaForm}.
641 */
642 private byte[] generateCustomizedCodeBytes() {
643 classFilePrologue();
644
645 // Suppress this method in backtraces displayed to the user.
646 mv.visitAnnotation(LF_HIDDEN_SIG, true);
647
648 // Mark this method as a compiled LambdaForm
649 mv.visitAnnotation(LF_COMPILED_SIG, true);
650
651 if (lambdaForm.forceInline) {
652 // Force inlining of this invoker method.
653 mv.visitAnnotation(FORCEINLINE_SIG, true);
654 } else {
655 mv.visitAnnotation(DONTINLINE_SIG, true);
656 }
657
658 constantPlaceholder(lambdaForm); // keep LambdaForm instance & its compiled form lifetime tightly coupled.
659
660 if (lambdaForm.customized != null) {
661 // Since LambdaForm is customized for a particular MethodHandle, it's safe to substitute
662 // receiver MethodHandle (at slot #0) with an embedded constant and use it instead.
663 // It enables more efficient code generation in some situations, since embedded constants
664 // are compile-time constants for JIT compiler.
665 mv.visitLdcInsn(constantPlaceholder(lambdaForm.customized));
666 mv.visitTypeInsn(Opcodes.CHECKCAST, MH);
667 assert(checkActualReceiver()); // expects MethodHandle on top of the stack
668 mv.visitVarInsn(Opcodes.ASTORE, localsMap[0]);
669 }
670
671 // iterate over the form's names, generating bytecode instructions for each
672 // start iterating at the first name following the arguments
673 Name onStack = null;
674 for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) {
675 Name name = lambdaForm.names[i];
676
677 emitStoreResult(onStack);
678 onStack = name; // unless otherwise modified below
679 MethodHandleImpl.Intrinsic intr = name.function.intrinsicName();
680 switch (intr) {
681 case SELECT_ALTERNATIVE:
682 assert isSelectAlternative(i);
683 if (PROFILE_GWT) {
684 assert(name.arguments[0] instanceof Name &&
685 nameRefersTo((Name)name.arguments[0], MethodHandleImpl.class, "profileBoolean"));
686 mv.visitAnnotation(INJECTEDPROFILE_SIG, true);
687 }
688 onStack = emitSelectAlternative(name, lambdaForm.names[i+1]);
689 i++; // skip MH.invokeBasic of the selectAlternative result
690 continue;
691 case GUARD_WITH_CATCH:
692 assert isGuardWithCatch(i);
693 onStack = emitGuardWithCatch(i);
694 i = i+2; // Jump to the end of GWC idiom
695 continue;
696 case NEW_ARRAY:
697 Class<?> rtype = name.function.methodType().returnType();
698 if (isStaticallyNameable(rtype)) {
699 emitNewArray(name);
700 continue;
701 }
702 break;
703 case ARRAY_LOAD:
704 emitArrayLoad(name);
705 continue;
706 case ARRAY_STORE:
707 emitArrayStore(name);
708 continue;
709 case ARRAY_LENGTH:
710 emitArrayLength(name);
711 continue;
712 case IDENTITY:
713 assert(name.arguments.length == 1);
714 emitPushArguments(name);
715 continue;
716 case ZERO:
717 assert(name.arguments.length == 0);
718 emitConst(name.type.basicTypeWrapper().zero());
719 continue;
720 case NONE:
721 // no intrinsic associated
722 break;
723 default:
724 throw newInternalError("Unknown intrinsic: "+intr);
725 }
726
727 MemberName member = name.function.member();
728 if (isStaticallyInvocable(member)) {
729 emitStaticInvoke(member, name);
730 } else {
731 emitInvoke(name);
732 }
733 }
734
735 // return statement
736 emitReturn(onStack);
737
738 classFileEpilogue();
739 bogusMethod(lambdaForm);
740
741 final byte[] classFile = cw.toByteArray();
742 maybeDump(className, classFile);
743 return classFile;
744 }
745
746 void emitArrayLoad(Name name) { emitArrayOp(name, Opcodes.AALOAD); }
747 void emitArrayStore(Name name) { emitArrayOp(name, Opcodes.AASTORE); }
748 void emitArrayLength(Name name) { emitArrayOp(name, Opcodes.ARRAYLENGTH); }
749
750 void emitArrayOp(Name name, int arrayOpcode) {
751 assert arrayOpcode == Opcodes.AALOAD || arrayOpcode == Opcodes.AASTORE || arrayOpcode == Opcodes.ARRAYLENGTH;
752 Class<?> elementType = name.function.methodType().parameterType(0).getComponentType();
753 assert elementType != null;
754 emitPushArguments(name);
755 if (arrayOpcode != Opcodes.ARRAYLENGTH && elementType.isPrimitive()) {
756 Wrapper w = Wrapper.forPrimitiveType(elementType);
757 arrayOpcode = arrayInsnOpcode(arrayTypeCode(w), arrayOpcode);
758 }
759 mv.visitInsn(arrayOpcode);
760 }
761
762 /**
763 * Emit an invoke for the given name.
764 */
765 void emitInvoke(Name name) {
766 assert(!isLinkerMethodInvoke(name)); // should use the static path for these
767 if (true) {
768 // push receiver
769 MethodHandle target = name.function.resolvedHandle();
770 assert(target != null) : name.exprString();
771 mv.visitLdcInsn(constantPlaceholder(target));
772 emitReferenceCast(MethodHandle.class, target);
773 } else {
774 // load receiver
775 emitAloadInsn(0);
776 emitReferenceCast(MethodHandle.class, null);
777 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", LF_SIG);
778 mv.visitFieldInsn(Opcodes.GETFIELD, LF, "names", LFN_SIG);
779 // TODO more to come
780 }
781
782 // push arguments
783 emitPushArguments(name);
784
785 // invocation
786 MethodType type = name.function.methodType();
787 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
788 }
789
790 private static Class<?>[] STATICALLY_INVOCABLE_PACKAGES = {
791 // Sample classes from each package we are willing to bind to statically:
792 java.lang.Object.class,
793 java.util.Arrays.class,
794 jdk.internal.misc.Unsafe.class
795 //MethodHandle.class already covered
796 };
797
798 static boolean isStaticallyInvocable(NamedFunction[] functions) {
799 for (NamedFunction nf : functions) {
800 if (!isStaticallyInvocable(nf.member())) {
801 return false;
802 }
803 }
804 return true;
805 }
806
807 static boolean isStaticallyInvocable(Name name) {
808 return isStaticallyInvocable(name.function.member());
809 }
810
811 static boolean isStaticallyInvocable(MemberName member) {
812 if (member == null) return false;
813 if (member.isConstructor()) return false;
814 Class<?> cls = member.getDeclaringClass();
815 if (cls.isArray() || cls.isPrimitive())
816 return false; // FIXME
817 if (cls.isAnonymousClass() || cls.isLocalClass())
818 return false; // inner class of some sort
819 if (cls.getClassLoader() != MethodHandle.class.getClassLoader())
820 return false; // not on BCP
821 if (ReflectUtil.isVMAnonymousClass(cls)) // FIXME: switch to supported API once it is added
822 return false;
823 MethodType mtype = member.getMethodOrFieldType();
824 if (!isStaticallyNameable(mtype.returnType()))
825 return false;
826 for (Class<?> ptype : mtype.parameterArray())
827 if (!isStaticallyNameable(ptype))
828 return false;
829 if (!member.isPrivate() && VerifyAccess.isSamePackage(MethodHandle.class, cls))
830 return true; // in java.lang.invoke package
831 if (member.isPublic() && isStaticallyNameable(cls))
832 return true;
833 return false;
834 }
835
836 static boolean isStaticallyNameable(Class<?> cls) {
837 if (cls == Object.class)
838 return true;
839 while (cls.isArray())
840 cls = cls.getComponentType();
841 if (cls.isPrimitive())
842 return true; // int[].class, for example
843 if (ReflectUtil.isVMAnonymousClass(cls)) // FIXME: switch to supported API once it is added
844 return false;
845 // could use VerifyAccess.isClassAccessible but the following is a safe approximation
846 if (cls.getClassLoader() != Object.class.getClassLoader())
847 return false;
848 if (VerifyAccess.isSamePackage(MethodHandle.class, cls))
849 return true;
850 if (!Modifier.isPublic(cls.getModifiers()))
851 return false;
852 for (Class<?> pkgcls : STATICALLY_INVOCABLE_PACKAGES) {
853 if (VerifyAccess.isSamePackage(pkgcls, cls))
854 return true;
855 }
856 return false;
857 }
858
859 void emitStaticInvoke(Name name) {
860 emitStaticInvoke(name.function.member(), name);
861 }
862
863 /**
864 * Emit an invoke for the given name, using the MemberName directly.
865 */
866 void emitStaticInvoke(MemberName member, Name name) {
867 assert(member.equals(name.function.member()));
868 Class<?> defc = member.getDeclaringClass();
869 String cname = getInternalName(defc);
870 String mname = member.getName();
871 String mtype;
872 byte refKind = member.getReferenceKind();
873 if (refKind == REF_invokeSpecial) {
874 // in order to pass the verifier, we need to convert this to invokevirtual in all cases
875 assert(member.canBeStaticallyBound()) : member;
876 refKind = REF_invokeVirtual;
877 }
878
879 assert(!(member.getDeclaringClass().isInterface() && refKind == REF_invokeVirtual));
880
881 // push arguments
882 emitPushArguments(name);
883
884 // invocation
885 if (member.isMethod()) {
886 mtype = member.getMethodType().toMethodDescriptorString();
887 mv.visitMethodInsn(refKindOpcode(refKind), cname, mname, mtype,
888 member.getDeclaringClass().isInterface());
889 } else {
890 mtype = MethodType.toFieldDescriptorString(member.getFieldType());
891 mv.visitFieldInsn(refKindOpcode(refKind), cname, mname, mtype);
892 }
893 // Issue a type assertion for the result, so we can avoid casts later.
894 if (name.type == L_TYPE) {
895 Class<?> rtype = member.getInvocationType().returnType();
896 assert(!rtype.isPrimitive());
897 if (rtype != Object.class && !rtype.isInterface()) {
898 assertStaticType(rtype, name);
899 }
900 }
901 }
902
903 void emitNewArray(Name name) throws InternalError {
904 Class<?> rtype = name.function.methodType().returnType();
905 if (name.arguments.length == 0) {
906 // The array will be a constant.
907 Object emptyArray;
908 try {
909 emptyArray = name.function.resolvedHandle().invoke();
910 } catch (Throwable ex) {
911 throw newInternalError(ex);
912 }
913 assert(java.lang.reflect.Array.getLength(emptyArray) == 0);
914 assert(emptyArray.getClass() == rtype); // exact typing
915 mv.visitLdcInsn(constantPlaceholder(emptyArray));
916 emitReferenceCast(rtype, emptyArray);
917 return;
918 }
919 Class<?> arrayElementType = rtype.getComponentType();
920 assert(arrayElementType != null);
921 emitIconstInsn(name.arguments.length);
922 int xas = Opcodes.AASTORE;
923 if (!arrayElementType.isPrimitive()) {
924 mv.visitTypeInsn(Opcodes.ANEWARRAY, getInternalName(arrayElementType));
925 } else {
926 byte tc = arrayTypeCode(Wrapper.forPrimitiveType(arrayElementType));
927 xas = arrayInsnOpcode(tc, xas);
928 mv.visitIntInsn(Opcodes.NEWARRAY, tc);
929 }
930 // store arguments
931 for (int i = 0; i < name.arguments.length; i++) {
932 mv.visitInsn(Opcodes.DUP);
933 emitIconstInsn(i);
934 emitPushArgument(name, i);
935 mv.visitInsn(xas);
936 }
937 // the array is left on the stack
938 assertStaticType(rtype, name);
939 }
940 int refKindOpcode(byte refKind) {
941 switch (refKind) {
942 case REF_invokeVirtual: return Opcodes.INVOKEVIRTUAL;
943 case REF_invokeStatic: return Opcodes.INVOKESTATIC;
944 case REF_invokeSpecial: return Opcodes.INVOKESPECIAL;
945 case REF_invokeInterface: return Opcodes.INVOKEINTERFACE;
946 case REF_getField: return Opcodes.GETFIELD;
947 case REF_putField: return Opcodes.PUTFIELD;
948 case REF_getStatic: return Opcodes.GETSTATIC;
949 case REF_putStatic: return Opcodes.PUTSTATIC;
950 }
951 throw new InternalError("refKind="+refKind);
952 }
953
954 /**
955 * Check if MemberName is a call to a method named {@code name} in class {@code declaredClass}.
956 */
957 private boolean memberRefersTo(MemberName member, Class<?> declaringClass, String name) {
958 return member != null &&
959 member.getDeclaringClass() == declaringClass &&
960 member.getName().equals(name);
961 }
962 private boolean nameRefersTo(Name name, Class<?> declaringClass, String methodName) {
963 return name.function != null &&
964 memberRefersTo(name.function.member(), declaringClass, methodName);
965 }
966
967 /**
968 * Check if MemberName is a call to MethodHandle.invokeBasic.
969 */
970 private boolean isInvokeBasic(Name name) {
971 if (name.function == null)
972 return false;
973 if (name.arguments.length < 1)
974 return false; // must have MH argument
975 MemberName member = name.function.member();
976 return memberRefersTo(member, MethodHandle.class, "invokeBasic") &&
977 !member.isPublic() && !member.isStatic();
978 }
979
980 /**
981 * Check if MemberName is a call to MethodHandle.linkToStatic, etc.
982 */
983 private boolean isLinkerMethodInvoke(Name name) {
984 if (name.function == null)
985 return false;
986 if (name.arguments.length < 1)
987 return false; // must have MH argument
988 MemberName member = name.function.member();
989 return member != null &&
990 member.getDeclaringClass() == MethodHandle.class &&
991 !member.isPublic() && member.isStatic() &&
992 member.getName().startsWith("linkTo");
993 }
994
995 /**
996 * Check if i-th name is a call to MethodHandleImpl.selectAlternative.
997 */
998 private boolean isSelectAlternative(int pos) {
999 // selectAlternative idiom:
1000 // t_{n}:L=MethodHandleImpl.selectAlternative(...)
1001 // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
1002 if (pos+1 >= lambdaForm.names.length) return false;
1003 Name name0 = lambdaForm.names[pos];
1004 Name name1 = lambdaForm.names[pos+1];
1005 return nameRefersTo(name0, MethodHandleImpl.class, "selectAlternative") &&
1006 isInvokeBasic(name1) &&
1007 name1.lastUseIndex(name0) == 0 && // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
1008 lambdaForm.lastUseIndex(name0) == pos+1; // t_{n} is local: used only in t_{n+1}
1009 }
1010
1011 /**
1012 * Check if i-th name is a start of GuardWithCatch idiom.
1013 */
1014 private boolean isGuardWithCatch(int pos) {
1015 // GuardWithCatch idiom:
1016 // t_{n}:L=MethodHandle.invokeBasic(...)
1017 // t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
1018 // t_{n+2}:?=MethodHandle.invokeBasic(t_{n+1})
1019 if (pos+2 >= lambdaForm.names.length) return false;
1020 Name name0 = lambdaForm.names[pos];
1021 Name name1 = lambdaForm.names[pos+1];
1022 Name name2 = lambdaForm.names[pos+2];
1023 return nameRefersTo(name1, MethodHandleImpl.class, "guardWithCatch") &&
1024 isInvokeBasic(name0) &&
1025 isInvokeBasic(name2) &&
1026 name1.lastUseIndex(name0) == 3 && // t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
1027 lambdaForm.lastUseIndex(name0) == pos+1 && // t_{n} is local: used only in t_{n+1}
1028 name2.lastUseIndex(name1) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(t_{n+1})
1029 lambdaForm.lastUseIndex(name1) == pos+2; // t_{n+1} is local: used only in t_{n+2}
1030 }
1031
1032 /**
1033 * Emit bytecode for the selectAlternative idiom.
1034 *
1035 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithTest):
1036 * <blockquote><pre>{@code
1037 * Lambda(a0:L,a1:I)=>{
1038 * t2:I=foo.test(a1:I);
1039 * t3:L=MethodHandleImpl.selectAlternative(t2:I,(MethodHandle(int)int),(MethodHandle(int)int));
1040 * t4:I=MethodHandle.invokeBasic(t3:L,a1:I);t4:I}
1041 * }</pre></blockquote>
1042 */
1043 private Name emitSelectAlternative(Name selectAlternativeName, Name invokeBasicName) {
1044 assert isStaticallyInvocable(invokeBasicName);
1045
1046 Name receiver = (Name) invokeBasicName.arguments[0];
1047
1048 Label L_fallback = new Label();
1049 Label L_done = new Label();
1050
1051 // load test result
1052 emitPushArgument(selectAlternativeName, 0);
1053
1054 // if_icmpne L_fallback
1055 mv.visitJumpInsn(Opcodes.IFEQ, L_fallback);
1056
1057 // invoke selectAlternativeName.arguments[1]
1058 Class<?>[] preForkClasses = localClasses.clone();
1059 emitPushArgument(selectAlternativeName, 1); // get 2nd argument of selectAlternative
1060 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
1061 emitStaticInvoke(invokeBasicName);
1062
1063 // goto L_done
1064 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1065
1066 // L_fallback:
1067 mv.visitLabel(L_fallback);
1068
1069 // invoke selectAlternativeName.arguments[2]
1070 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
1071 emitPushArgument(selectAlternativeName, 2); // get 3rd argument of selectAlternative
1072 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
1073 emitStaticInvoke(invokeBasicName);
1074
1075 // L_done:
1076 mv.visitLabel(L_done);
1077 // for now do not bother to merge typestate; just reset to the dominator state
1078 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
1079
1080 return invokeBasicName; // return what's on stack
1081 }
1082
1083 /**
1084 * Emit bytecode for the guardWithCatch idiom.
1085 *
1086 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithCatch):
1087 * <blockquote><pre>{@code
1088 * guardWithCatch=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{
1089 * t8:L=MethodHandle.invokeBasic(a4:L,a6:L,a7:L);
1090 * t9:L=MethodHandleImpl.guardWithCatch(a1:L,a2:L,a3:L,t8:L);
1091 * t10:I=MethodHandle.invokeBasic(a5:L,t9:L);t10:I}
1092 * }</pre></blockquote>
1093 *
1094 * It is compiled into bytecode equivalent of the following code:
1095 * <blockquote><pre>{@code
1096 * try {
1097 * return a1.invokeBasic(a6, a7);
1098 * } catch (Throwable e) {
1099 * if (!a2.isInstance(e)) throw e;
1100 * return a3.invokeBasic(ex, a6, a7);
1101 * }}
1102 */
1103 private Name emitGuardWithCatch(int pos) {
1104 Name args = lambdaForm.names[pos];
1105 Name invoker = lambdaForm.names[pos+1];
1106 Name result = lambdaForm.names[pos+2];
1107
1108 Label L_startBlock = new Label();
1109 Label L_endBlock = new Label();
1110 Label L_handler = new Label();
1111 Label L_done = new Label();
1112
1113 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1114 MethodType type = args.function.resolvedHandle().type()
1115 .dropParameterTypes(0,1)
1116 .changeReturnType(returnType);
1117
1118 mv.visitTryCatchBlock(L_startBlock, L_endBlock, L_handler, "java/lang/Throwable");
1119
1120 // Normal case
1121 mv.visitLabel(L_startBlock);
1122 // load target
1123 emitPushArgument(invoker, 0);
1124 emitPushArguments(args, 1); // skip 1st argument: method handle
1125 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
1126 mv.visitLabel(L_endBlock);
1127 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1128
1129 // Exceptional case
1130 mv.visitLabel(L_handler);
1131
1132 // Check exception's type
1133 mv.visitInsn(Opcodes.DUP);
1134 // load exception class
1135 emitPushArgument(invoker, 1);
1136 mv.visitInsn(Opcodes.SWAP);
1137 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Class", "isInstance", "(Ljava/lang/Object;)Z", false);
1138 Label L_rethrow = new Label();
1139 mv.visitJumpInsn(Opcodes.IFEQ, L_rethrow);
1140
1141 // Invoke catcher
1142 // load catcher
1143 emitPushArgument(invoker, 2);
1144 mv.visitInsn(Opcodes.SWAP);
1145 emitPushArguments(args, 1); // skip 1st argument: method handle
1146 MethodType catcherType = type.insertParameterTypes(0, Throwable.class);
1147 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", catcherType.basicType().toMethodDescriptorString(), false);
1148 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1149
1150 mv.visitLabel(L_rethrow);
1151 mv.visitInsn(Opcodes.ATHROW);
1152
1153 mv.visitLabel(L_done);
1154
1155 return result;
1156 }
1157
1158 private void emitPushArguments(Name args) {
1159 emitPushArguments(args, 0);
1160 }
1161
1162 private void emitPushArguments(Name args, int start) {
1163 for (int i = start; i < args.arguments.length; i++) {
1164 emitPushArgument(args, i);
1165 }
1166 }
1167
1168 private void emitPushArgument(Name name, int paramIndex) {
1169 Object arg = name.arguments[paramIndex];
1170 Class<?> ptype = name.function.methodType().parameterType(paramIndex);
1171 emitPushArgument(ptype, arg);
1172 }
1173
1174 private void emitPushArgument(Class<?> ptype, Object arg) {
1175 BasicType bptype = basicType(ptype);
1176 if (arg instanceof Name) {
1177 Name n = (Name) arg;
1178 emitLoadInsn(n.type, n.index());
1179 emitImplicitConversion(n.type, ptype, n);
1180 } else if ((arg == null || arg instanceof String) && bptype == L_TYPE) {
1181 emitConst(arg);
1182 } else {
1183 if (Wrapper.isWrapperType(arg.getClass()) && bptype != L_TYPE) {
1184 emitConst(arg);
1185 } else {
1186 mv.visitLdcInsn(constantPlaceholder(arg));
1187 emitImplicitConversion(L_TYPE, ptype, arg);
1188 }
1189 }
1190 }
1191
1192 /**
1193 * Store the name to its local, if necessary.
1194 */
1195 private void emitStoreResult(Name name) {
1196 if (name != null && name.type != V_TYPE) {
1197 // non-void: actually assign
1198 emitStoreInsn(name.type, name.index());
1199 }
1200 }
1201
1202 /**
1203 * Emits a return statement from a LF invoker. If required, the result type is cast to the correct return type.
1204 */
1205 private void emitReturn(Name onStack) {
1206 // return statement
1207 Class<?> rclass = invokerType.returnType();
1208 BasicType rtype = lambdaForm.returnType();
1209 assert(rtype == basicType(rclass)); // must agree
1210 if (rtype == V_TYPE) {
1211 // void
1212 mv.visitInsn(Opcodes.RETURN);
1213 // it doesn't matter what rclass is; the JVM will discard any value
1214 } else {
1215 LambdaForm.Name rn = lambdaForm.names[lambdaForm.result];
1216
1217 // put return value on the stack if it is not already there
1218 if (rn != onStack) {
1219 emitLoadInsn(rtype, lambdaForm.result);
1220 }
1221
1222 emitImplicitConversion(rtype, rclass, rn);
1223
1224 // generate actual return statement
1225 emitReturnInsn(rtype);
1226 }
1227 }
1228
1229 /**
1230 * Emit a type conversion bytecode casting from "from" to "to".
1231 */
1232 private void emitPrimCast(Wrapper from, Wrapper to) {
1233 // Here's how.
1234 // - indicates forbidden
1235 // <-> indicates implicit
1236 // to ----> boolean byte short char int long float double
1237 // from boolean <-> - - - - - - -
1238 // byte - <-> i2s i2c <-> i2l i2f i2d
1239 // short - i2b <-> i2c <-> i2l i2f i2d
1240 // char - i2b i2s <-> <-> i2l i2f i2d
1241 // int - i2b i2s i2c <-> i2l i2f i2d
1242 // long - l2i,i2b l2i,i2s l2i,i2c l2i <-> l2f l2d
1243 // float - f2i,i2b f2i,i2s f2i,i2c f2i f2l <-> f2d
1244 // double - d2i,i2b d2i,i2s d2i,i2c d2i d2l d2f <->
1245 if (from == to) {
1246 // no cast required, should be dead code anyway
1247 return;
1248 }
1249 if (from.isSubwordOrInt()) {
1250 // cast from {byte,short,char,int} to anything
1251 emitI2X(to);
1252 } else {
1253 // cast from {long,float,double} to anything
1254 if (to.isSubwordOrInt()) {
1255 // cast to {byte,short,char,int}
1256 emitX2I(from);
1257 if (to.bitWidth() < 32) {
1258 // targets other than int require another conversion
1259 emitI2X(to);
1260 }
1261 } else {
1262 // cast to {long,float,double} - this is verbose
1263 boolean error = false;
1264 switch (from) {
1265 case LONG:
1266 switch (to) {
1267 case FLOAT: mv.visitInsn(Opcodes.L2F); break;
1268 case DOUBLE: mv.visitInsn(Opcodes.L2D); break;
1269 default: error = true; break;
1270 }
1271 break;
1272 case FLOAT:
1273 switch (to) {
1274 case LONG : mv.visitInsn(Opcodes.F2L); break;
1275 case DOUBLE: mv.visitInsn(Opcodes.F2D); break;
1276 default: error = true; break;
1277 }
1278 break;
1279 case DOUBLE:
1280 switch (to) {
1281 case LONG : mv.visitInsn(Opcodes.D2L); break;
1282 case FLOAT: mv.visitInsn(Opcodes.D2F); break;
1283 default: error = true; break;
1284 }
1285 break;
1286 default:
1287 error = true;
1288 break;
1289 }
1290 if (error) {
1291 throw new IllegalStateException("unhandled prim cast: " + from + "2" + to);
1292 }
1293 }
1294 }
1295 }
1296
1297 private void emitI2X(Wrapper type) {
1298 switch (type) {
1299 case BYTE: mv.visitInsn(Opcodes.I2B); break;
1300 case SHORT: mv.visitInsn(Opcodes.I2S); break;
1301 case CHAR: mv.visitInsn(Opcodes.I2C); break;
1302 case INT: /* naught */ break;
1303 case LONG: mv.visitInsn(Opcodes.I2L); break;
1304 case FLOAT: mv.visitInsn(Opcodes.I2F); break;
1305 case DOUBLE: mv.visitInsn(Opcodes.I2D); break;
1306 case BOOLEAN:
1307 // For compatibility with ValueConversions and explicitCastArguments:
1308 mv.visitInsn(Opcodes.ICONST_1);
1309 mv.visitInsn(Opcodes.IAND);
1310 break;
1311 default: throw new InternalError("unknown type: " + type);
1312 }
1313 }
1314
1315 private void emitX2I(Wrapper type) {
1316 switch (type) {
1317 case LONG: mv.visitInsn(Opcodes.L2I); break;
1318 case FLOAT: mv.visitInsn(Opcodes.F2I); break;
1319 case DOUBLE: mv.visitInsn(Opcodes.D2I); break;
1320 default: throw new InternalError("unknown type: " + type);
1321 }
1322 }
1323
1324 /**
1325 * Generate bytecode for a LambdaForm.vmentry which calls interpretWithArguments.
1326 */
1327 static MemberName generateLambdaFormInterpreterEntryPoint(MethodType mt) {
1328 assert(isValidSignature(basicTypeSignature(mt)));
1329 String name = "interpret_"+basicTypeChar(mt.returnType());
1330 MethodType type = mt; // includes leading argument
1331 type = type.changeParameterType(0, MethodHandle.class);
1332 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("LFI", name, type);
1333 return g.loadMethod(g.generateLambdaFormInterpreterEntryPointBytes());
1334 }
1335
1336 private byte[] generateLambdaFormInterpreterEntryPointBytes() {
1337 classFilePrologue();
1338
1339 // Suppress this method in backtraces displayed to the user.
1340 mv.visitAnnotation(LF_HIDDEN_SIG, true);
1341
1342 // Don't inline the interpreter entry.
1343 mv.visitAnnotation(DONTINLINE_SIG, true);
1344
1345 // create parameter array
1346 emitIconstInsn(invokerType.parameterCount());
1347 mv.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object");
1348
1349 // fill parameter array
1350 for (int i = 0; i < invokerType.parameterCount(); i++) {
1351 Class<?> ptype = invokerType.parameterType(i);
1352 mv.visitInsn(Opcodes.DUP);
1353 emitIconstInsn(i);
1354 emitLoadInsn(basicType(ptype), i);
1355 // box if primitive type
1356 if (ptype.isPrimitive()) {
1357 emitBoxing(Wrapper.forPrimitiveType(ptype));
1358 }
1359 mv.visitInsn(Opcodes.AASTORE);
1360 }
1361 // invoke
1362 emitAloadInsn(0);
1363 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", "Ljava/lang/invoke/LambdaForm;");
1364 mv.visitInsn(Opcodes.SWAP); // swap form and array; avoid local variable
1365 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, LF, "interpretWithArguments", "([Ljava/lang/Object;)Ljava/lang/Object;", false);
1366
1367 // maybe unbox
1368 Class<?> rtype = invokerType.returnType();
1369 if (rtype.isPrimitive() && rtype != void.class) {
1370 emitUnboxing(Wrapper.forPrimitiveType(rtype));
1371 }
1372
1373 // return statement
1374 emitReturnInsn(basicType(rtype));
1375
1376 classFileEpilogue();
1377 bogusMethod(invokerType);
1378
1379 final byte[] classFile = cw.toByteArray();
1380 maybeDump(className, classFile);
1381 return classFile;
1382 }
1383
1384 /**
1385 * Generate bytecode for a NamedFunction invoker.
1386 */
1387 static MemberName generateNamedFunctionInvoker(MethodTypeForm typeForm) {
1388 MethodType invokerType = NamedFunction.INVOKER_METHOD_TYPE;
1389 String invokerName = "invoke_" + shortenSignature(basicTypeSignature(typeForm.erasedType()));
1390 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("NFI", invokerName, invokerType);
1391 return g.loadMethod(g.generateNamedFunctionInvokerImpl(typeForm));
1392 }
1393
1394 private byte[] generateNamedFunctionInvokerImpl(MethodTypeForm typeForm) {
1395 MethodType dstType = typeForm.erasedType();
1396 classFilePrologue();
1397
1398 // Suppress this method in backtraces displayed to the user.
1399 mv.visitAnnotation(LF_HIDDEN_SIG, true);
1400
1401 // Force inlining of this invoker method.
1402 mv.visitAnnotation(FORCEINLINE_SIG, true);
1403
1404 // Load receiver
1405 emitAloadInsn(0);
1406
1407 // Load arguments from array
1408 for (int i = 0; i < dstType.parameterCount(); i++) {
1409 emitAloadInsn(1);
1410 emitIconstInsn(i);
1411 mv.visitInsn(Opcodes.AALOAD);
1412
1413 // Maybe unbox
1414 Class<?> dptype = dstType.parameterType(i);
1415 if (dptype.isPrimitive()) {
1416 Class<?> sptype = dstType.basicType().wrap().parameterType(i);
1417 Wrapper dstWrapper = Wrapper.forBasicType(dptype);
1418 Wrapper srcWrapper = dstWrapper.isSubwordOrInt() ? Wrapper.INT : dstWrapper; // narrow subword from int
1419 emitUnboxing(srcWrapper);
1420 emitPrimCast(srcWrapper, dstWrapper);
1421 }
1422 }
1423
1424 // Invoke
1425 String targetDesc = dstType.basicType().toMethodDescriptorString();
1426 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", targetDesc, false);
1427
1428 // Box primitive types
1429 Class<?> rtype = dstType.returnType();
1430 if (rtype != void.class && rtype.isPrimitive()) {
1431 Wrapper srcWrapper = Wrapper.forBasicType(rtype);
1432 Wrapper dstWrapper = srcWrapper.isSubwordOrInt() ? Wrapper.INT : srcWrapper; // widen subword to int
1433 // boolean casts not allowed
1434 emitPrimCast(srcWrapper, dstWrapper);
1435 emitBoxing(dstWrapper);
1436 }
1437
1438 // If the return type is void we return a null reference.
1439 if (rtype == void.class) {
1440 mv.visitInsn(Opcodes.ACONST_NULL);
1441 }
1442 emitReturnInsn(L_TYPE); // NOTE: NamedFunction invokers always return a reference value.
1443
1444 classFileEpilogue();
1445 bogusMethod(dstType);
1446
1447 final byte[] classFile = cw.toByteArray();
1448 maybeDump(className, classFile);
1449 return classFile;
1450 }
1451
1452 /**
1453 * Emit a bogus method that just loads some string constants. This is to get the constants into the constant pool
1454 * for debugging purposes.
1455 */
1456 private void bogusMethod(Object... os) {
1457 if (DUMP_CLASS_FILES) {
1458 mv = cw.visitMethod(Opcodes.ACC_STATIC, "dummy", "()V", null, null);
1459 for (Object o : os) {
1460 mv.visitLdcInsn(o.toString());
1461 mv.visitInsn(Opcodes.POP);
1462 }
1463 mv.visitInsn(Opcodes.RETURN);
1464 mv.visitMaxs(0, 0);
1465 mv.visitEnd();
1466 }
1467 }
1468 }