1 /*
2 * Copyright (c) 2012, 2013, 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$Name";
55 private static final String CLS = "java/lang/Class";
56 private static final String OBJ = "java/lang/Object";
57 private static final String OBJARY = "[Ljava/lang/Object;";
58
59 private static final String LF_SIG = "L" + LF + ";";
60 private static final String LFN_SIG = "L" + LFN + ";";
61 private static final String LL_SIG = "(L" + OBJ + ";)L" + OBJ + ";";
62 private static final String CLL_SIG = "(L" + CLS + ";L" + OBJ + ";)L" + OBJ + ";";
63
64 /** Name of its super class*/
65 private static final String superName = OBJ;
66
67 /** Name of new class */
68 private final String className;
69
70 /** Name of the source file (for stack trace printing). */
71 private final String sourceFile;
72
73 private final LambdaForm lambdaForm;
74 private final String invokerName;
75 private final MethodType invokerType;
76
77 /** Info about local variables in compiled lambda form */
78 private final int[] localsMap; // index
79 private final BasicType[] localTypes; // basic type
80 private final Class<?>[] localClasses; // type
81
82 /** ASM bytecode generation. */
83 private ClassWriter cw;
84 private MethodVisitor mv;
85
86 private static final MemberName.Factory MEMBERNAME_FACTORY = MemberName.getFactory();
87 private static final Class<?> HOST_CLASS = LambdaForm.class;
88
89 /** Main constructor; other constructors delegate to this one. */
90 private InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize,
91 String className, String invokerName, MethodType invokerType) {
92 if (invokerName.contains(".")) {
93 int p = invokerName.indexOf('.');
94 className = invokerName.substring(0, p);
95 invokerName = invokerName.substring(p+1);
96 }
97 if (DUMP_CLASS_FILES) {
98 className = makeDumpableClassName(className);
99 }
100 this.className = LF + "$" + className;
101 this.sourceFile = "LambdaForm$" + className;
102 this.lambdaForm = lambdaForm;
103 this.invokerName = invokerName;
104 this.invokerType = invokerType;
105 this.localsMap = new int[localsMapSize+1];
106 // last entry of localsMap is count of allocated local slots
107 this.localTypes = new BasicType[localsMapSize+1];
108 this.localClasses = new Class<?>[localsMapSize+1];
109 }
110
111 /** For generating LambdaForm interpreter entry points. */
112 private InvokerBytecodeGenerator(String className, String invokerName, MethodType invokerType) {
113 this(null, invokerType.parameterCount(),
114 className, invokerName, invokerType);
115 // Create an array to map name indexes to locals indexes.
116 localTypes[localTypes.length - 1] = V_TYPE;
117 for (int i = 0; i < localsMap.length; i++) {
118 localsMap[i] = invokerType.parameterSlotCount() - invokerType.parameterSlotDepth(i);
119 if (i < invokerType.parameterCount())
120 localTypes[i] = basicType(invokerType.parameterType(i));
121 }
122 }
123
124 /** For generating customized code for a single LambdaForm. */
125 private InvokerBytecodeGenerator(String className, LambdaForm form, MethodType invokerType) {
126 this(form, form.names.length,
127 className, form.debugName, invokerType);
128 // Create an array to map name indexes to locals indexes.
129 Name[] names = form.names;
130 for (int i = 0, index = 0; i < localsMap.length; i++) {
131 localsMap[i] = index;
132 if (i < names.length) {
133 BasicType type = names[i].type();
134 index += type.basicTypeSlots();
135 localTypes[i] = type;
136 }
137 }
138 }
139
140
141 /** instance counters for dumped classes */
142 private final static HashMap<String,Integer> DUMP_CLASS_FILES_COUNTERS;
143 /** debugging flag for saving generated class files */
144 private final static File DUMP_CLASS_FILES_DIR;
145
146 static {
147 if (DUMP_CLASS_FILES) {
148 DUMP_CLASS_FILES_COUNTERS = new HashMap<>();
149 try {
150 File dumpDir = new File("DUMP_CLASS_FILES");
151 if (!dumpDir.exists()) {
152 dumpDir.mkdirs();
153 }
154 DUMP_CLASS_FILES_DIR = dumpDir;
155 System.out.println("Dumping class files to "+DUMP_CLASS_FILES_DIR+"/...");
156 } catch (Exception e) {
157 throw newInternalError(e);
158 }
159 } else {
160 DUMP_CLASS_FILES_COUNTERS = null;
161 DUMP_CLASS_FILES_DIR = null;
162 }
163 }
164
165 static void maybeDump(final String className, final byte[] classFile) {
166 if (DUMP_CLASS_FILES) {
167 java.security.AccessController.doPrivileged(
168 new java.security.PrivilegedAction<Void>() {
169 public Void run() {
170 try {
171 String dumpName = className;
172 //dumpName = dumpName.replace('/', '-');
173 File dumpFile = new File(DUMP_CLASS_FILES_DIR, dumpName+".class");
174 System.out.println("dump: " + dumpFile);
175 dumpFile.getParentFile().mkdirs();
176 FileOutputStream file = new FileOutputStream(dumpFile);
177 file.write(classFile);
178 file.close();
179 return null;
180 } catch (IOException ex) {
181 throw newInternalError(ex);
182 }
183 }
184 });
185 }
186
187 }
188
189 private static String makeDumpableClassName(String className) {
190 Integer ctr;
191 synchronized (DUMP_CLASS_FILES_COUNTERS) {
192 ctr = DUMP_CLASS_FILES_COUNTERS.get(className);
193 if (ctr == null) ctr = 0;
194 DUMP_CLASS_FILES_COUNTERS.put(className, ctr+1);
195 }
196 String sfx = ctr.toString();
197 while (sfx.length() < 3)
198 sfx = "0"+sfx;
199 className += sfx;
200 return className;
201 }
202
203 class CpPatch {
204 final int index;
205 final String placeholder;
206 final Object value;
207 CpPatch(int index, String placeholder, Object value) {
208 this.index = index;
209 this.placeholder = placeholder;
210 this.value = value;
211 }
212 public String toString() {
213 return "CpPatch/index="+index+",placeholder="+placeholder+",value="+value;
214 }
215 }
216
217 Map<Object, CpPatch> cpPatches = new HashMap<>();
218
219 int cph = 0; // for counting constant placeholders
220
221 String constantPlaceholder(Object arg) {
222 String cpPlaceholder = "CONSTANT_PLACEHOLDER_" + cph++;
223 if (DUMP_CLASS_FILES) cpPlaceholder += " <<" + debugString(arg) + ">>"; // debugging aid
224 if (cpPatches.containsKey(cpPlaceholder)) {
225 throw new InternalError("observed CP placeholder twice: " + cpPlaceholder);
226 }
227 // insert placeholder in CP and remember the patch
228 int index = cw.newConst((Object) cpPlaceholder); // TODO check if already in the constant pool
229 cpPatches.put(cpPlaceholder, new CpPatch(index, cpPlaceholder, arg));
230 return cpPlaceholder;
231 }
232
233 Object[] cpPatches(byte[] classFile) {
234 int size = getConstantPoolSize(classFile);
235 Object[] res = new Object[size];
236 for (CpPatch p : cpPatches.values()) {
237 if (p.index >= size)
238 throw new InternalError("in cpool["+size+"]: "+p+"\n"+Arrays.toString(Arrays.copyOf(classFile, 20)));
239 res[p.index] = p.value;
240 }
241 return res;
242 }
243
244 private static String debugString(Object arg) {
245 if (arg instanceof MethodHandle) {
246 MethodHandle mh = (MethodHandle) arg;
247 MemberName member = mh.internalMemberName();
248 if (member != null)
249 return member.toString();
250 return mh.debugString();
251 }
252 return arg.toString();
253 }
254
255 /**
256 * Extract the number of constant pool entries from a given class file.
257 *
258 * @param classFile the bytes of the class file in question.
259 * @return the number of entries in the constant pool.
260 */
261 private static int getConstantPoolSize(byte[] classFile) {
262 // The first few bytes:
263 // u4 magic;
264 // u2 minor_version;
265 // u2 major_version;
266 // u2 constant_pool_count;
267 return ((classFile[8] & 0xFF) << 8) | (classFile[9] & 0xFF);
268 }
269
270 /**
271 * Extract the MemberName of a newly-defined method.
272 */
273 private MemberName loadMethod(byte[] classFile) {
274 Class<?> invokerClass = loadAndInitializeInvokerClass(classFile, cpPatches(classFile));
275 return resolveInvokerMember(invokerClass, invokerName, invokerType);
276 }
277
278 /**
279 * Define a given class as anonymous class in the runtime system.
280 */
281 private static Class<?> loadAndInitializeInvokerClass(byte[] classBytes, Object[] patches) {
282 Class<?> invokerClass = UNSAFE.defineAnonymousClass(HOST_CLASS, classBytes, patches);
283 UNSAFE.ensureClassInitialized(invokerClass); // Make sure the class is initialized; VM might complain.
284 return invokerClass;
285 }
286
287 private static MemberName resolveInvokerMember(Class<?> invokerClass, String name, MethodType type) {
288 MemberName member = new MemberName(invokerClass, name, type, REF_invokeStatic);
289 //System.out.println("resolveInvokerMember => "+member);
290 //for (Method m : invokerClass.getDeclaredMethods()) System.out.println(" "+m);
291 try {
292 member = MEMBERNAME_FACTORY.resolveOrFail(REF_invokeStatic, member, HOST_CLASS, ReflectiveOperationException.class);
293 } catch (ReflectiveOperationException e) {
294 throw newInternalError(e);
295 }
296 //System.out.println("resolveInvokerMember => "+member);
297 return member;
298 }
299
300 /**
301 * Set up class file generation.
302 */
303 private void classFilePrologue() {
304 final int NOT_ACC_PUBLIC = 0; // not ACC_PUBLIC
305 cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
306 cw.visit(Opcodes.V1_8, NOT_ACC_PUBLIC + Opcodes.ACC_FINAL + Opcodes.ACC_SUPER, className, null, superName, null);
307 cw.visitSource(sourceFile, null);
308
309 String invokerDesc = invokerType.toMethodDescriptorString();
310 mv = cw.visitMethod(Opcodes.ACC_STATIC, invokerName, invokerDesc, null, null);
311 }
312
313 /**
314 * Tear down class file generation.
315 */
316 private void classFileEpilogue() {
317 mv.visitMaxs(0, 0);
318 mv.visitEnd();
319 }
320
321 /*
322 * Low-level emit helpers.
323 */
324 private void emitConst(Object con) {
325 if (con == null) {
326 mv.visitInsn(Opcodes.ACONST_NULL);
327 return;
328 }
329 if (con instanceof Integer) {
330 emitIconstInsn((int) con);
331 return;
332 }
333 if (con instanceof Long) {
334 long x = (long) con;
335 if (x == (short) x) {
336 emitIconstInsn((int) x);
337 mv.visitInsn(Opcodes.I2L);
338 return;
339 }
340 }
341 if (con instanceof Float) {
342 float x = (float) con;
343 if (x == (short) x) {
344 emitIconstInsn((int) x);
345 mv.visitInsn(Opcodes.I2F);
346 return;
347 }
348 }
349 if (con instanceof Double) {
350 double x = (double) con;
351 if (x == (short) x) {
352 emitIconstInsn((int) x);
353 mv.visitInsn(Opcodes.I2D);
354 return;
355 }
356 }
357 if (con instanceof Boolean) {
358 emitIconstInsn((boolean) con ? 1 : 0);
359 return;
360 }
361 // fall through:
362 mv.visitLdcInsn(con);
363 }
364
365 private void emitIconstInsn(int i) {
366 int opcode;
367 switch (i) {
368 case 0: opcode = Opcodes.ICONST_0; break;
369 case 1: opcode = Opcodes.ICONST_1; break;
370 case 2: opcode = Opcodes.ICONST_2; break;
371 case 3: opcode = Opcodes.ICONST_3; break;
372 case 4: opcode = Opcodes.ICONST_4; break;
373 case 5: opcode = Opcodes.ICONST_5; break;
374 default:
375 if (i == (byte) i) {
376 mv.visitIntInsn(Opcodes.BIPUSH, i & 0xFF);
377 } else if (i == (short) i) {
378 mv.visitIntInsn(Opcodes.SIPUSH, (char) i);
379 } else {
380 mv.visitLdcInsn(i);
381 }
382 return;
383 }
384 mv.visitInsn(opcode);
385 }
386
387 /*
388 * NOTE: These load/store methods use the localsMap to find the correct index!
389 */
390 private void emitLoadInsn(BasicType type, int index) {
391 int opcode = loadInsnOpcode(type);
392 mv.visitVarInsn(opcode, localsMap[index]);
393 }
394
395 private int loadInsnOpcode(BasicType type) throws InternalError {
396 switch (type) {
397 case I_TYPE: return Opcodes.ILOAD;
398 case J_TYPE: return Opcodes.LLOAD;
399 case F_TYPE: return Opcodes.FLOAD;
400 case D_TYPE: return Opcodes.DLOAD;
401 case L_TYPE: return Opcodes.ALOAD;
402 default:
403 throw new InternalError("unknown type: " + type);
404 }
405 }
406 private void emitAloadInsn(int index) {
407 emitLoadInsn(L_TYPE, index);
408 }
409
410 private void emitStoreInsn(BasicType type, int index) {
411 int opcode = storeInsnOpcode(type);
412 mv.visitVarInsn(opcode, localsMap[index]);
413 }
414
415 private int storeInsnOpcode(BasicType type) throws InternalError {
416 switch (type) {
417 case I_TYPE: return Opcodes.ISTORE;
418 case J_TYPE: return Opcodes.LSTORE;
419 case F_TYPE: return Opcodes.FSTORE;
420 case D_TYPE: return Opcodes.DSTORE;
421 case L_TYPE: return Opcodes.ASTORE;
422 default:
423 throw new InternalError("unknown type: " + type);
424 }
425 }
426 private void emitAstoreInsn(int index) {
427 emitStoreInsn(L_TYPE, index);
428 }
429
430 private byte arrayTypeCode(Wrapper elementType) {
431 switch (elementType) {
432 case BOOLEAN: return Opcodes.T_BOOLEAN;
433 case BYTE: return Opcodes.T_BYTE;
434 case CHAR: return Opcodes.T_CHAR;
435 case SHORT: return Opcodes.T_SHORT;
436 case INT: return Opcodes.T_INT;
437 case LONG: return Opcodes.T_LONG;
438 case FLOAT: return Opcodes.T_FLOAT;
439 case DOUBLE: return Opcodes.T_DOUBLE;
440 case OBJECT: return 0; // in place of Opcodes.T_OBJECT
441 default: throw new InternalError();
442 }
443 }
444
445 private int arrayInsnOpcode(byte tcode, int aaop) throws InternalError {
446 assert(aaop == Opcodes.AASTORE || aaop == Opcodes.AALOAD);
447 int xas;
448 switch (tcode) {
449 case Opcodes.T_BOOLEAN: xas = Opcodes.BASTORE; break;
450 case Opcodes.T_BYTE: xas = Opcodes.BASTORE; break;
451 case Opcodes.T_CHAR: xas = Opcodes.CASTORE; break;
452 case Opcodes.T_SHORT: xas = Opcodes.SASTORE; break;
453 case Opcodes.T_INT: xas = Opcodes.IASTORE; break;
454 case Opcodes.T_LONG: xas = Opcodes.LASTORE; break;
455 case Opcodes.T_FLOAT: xas = Opcodes.FASTORE; break;
456 case Opcodes.T_DOUBLE: xas = Opcodes.DASTORE; break;
457 case 0: xas = Opcodes.AASTORE; break;
458 default: throw new InternalError();
459 }
460 return xas - Opcodes.AASTORE + aaop;
461 }
462
463
464 private void freeFrameLocal(int oldFrameLocal) {
465 int i = indexForFrameLocal(oldFrameLocal);
466 if (i < 0) return;
467 BasicType type = localTypes[i];
468 int newFrameLocal = makeLocalTemp(type);
469 mv.visitVarInsn(loadInsnOpcode(type), oldFrameLocal);
470 mv.visitVarInsn(storeInsnOpcode(type), newFrameLocal);
471 assert(localsMap[i] == oldFrameLocal);
472 localsMap[i] = newFrameLocal;
473 assert(indexForFrameLocal(oldFrameLocal) < 0);
474 }
475 private int indexForFrameLocal(int frameLocal) {
476 for (int i = 0; i < localsMap.length; i++) {
477 if (localsMap[i] == frameLocal && localTypes[i] != V_TYPE)
478 return i;
479 }
480 return -1;
481 }
482 private int makeLocalTemp(BasicType type) {
483 int frameLocal = localsMap[localsMap.length - 1];
484 localsMap[localsMap.length - 1] = frameLocal + type.basicTypeSlots();
485 return frameLocal;
486 }
487
488 /**
489 * Emit a boxing call.
490 *
491 * @param wrapper primitive type class to box.
492 */
493 private void emitBoxing(Wrapper wrapper) {
494 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
495 String name = "valueOf";
496 String desc = "(" + wrapper.basicTypeChar() + ")L" + owner + ";";
497 mv.visitMethodInsn(Opcodes.INVOKESTATIC, owner, name, desc, false);
498 }
499
500 /**
501 * Emit an unboxing call (plus preceding checkcast).
502 *
503 * @param wrapper wrapper type class to unbox.
504 */
505 private void emitUnboxing(Wrapper wrapper) {
506 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
507 String name = wrapper.primitiveSimpleName() + "Value";
508 String desc = "()" + wrapper.basicTypeChar();
509 emitReferenceCast(wrapper.wrapperType(), null);
510 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, owner, name, desc, false);
511 }
512
513 /**
514 * Emit an implicit conversion for an argument which must be of the given pclass.
515 * This is usually a no-op, except when pclass is a subword type or a reference other than Object or an interface.
516 *
517 * @param ptype type of value present on stack
518 * @param pclass type of value required on stack
519 * @param arg compile-time representation of value on stack (Node, constant) or null if none
520 */
521 private void emitImplicitConversion(BasicType ptype, Class<?> pclass, Object arg) {
522 assert(basicType(pclass) == ptype); // boxing/unboxing handled by caller
523 if (pclass == ptype.basicTypeClass() && ptype != L_TYPE)
524 return; // nothing to do
525 switch (ptype) {
526 case L_TYPE:
527 if (VerifyType.isNullConversion(Object.class, pclass, false)) {
528 if (PROFILE_LEVEL > 0)
529 emitReferenceCast(Object.class, arg);
530 return;
531 }
532 emitReferenceCast(pclass, arg);
533 return;
534 case I_TYPE:
535 if (!VerifyType.isNullConversion(int.class, pclass, false))
536 emitPrimCast(ptype.basicTypeWrapper(), Wrapper.forPrimitiveType(pclass));
537 return;
538 }
539 throw newInternalError("bad implicit conversion: tc="+ptype+": "+pclass);
540 }
541
542 /** Update localClasses type map. Return true if the information is already present. */
543 private boolean assertStaticType(Class<?> cls, Name n) {
544 int local = n.index();
545 Class<?> aclass = localClasses[local];
546 if (aclass != null && (aclass == cls || cls.isAssignableFrom(aclass))) {
547 return true; // type info is already present
548 } else if (aclass == null || aclass.isAssignableFrom(cls)) {
549 localClasses[local] = cls; // type info can be improved
550 }
551 return false;
552 }
553
554 private void emitReferenceCast(Class<?> cls, Object arg) {
555 Name writeBack = null; // local to write back result
556 if (arg instanceof Name) {
557 Name n = (Name) arg;
558 if (assertStaticType(cls, n))
559 return; // this cast was already performed
560 if (lambdaForm.useCount(n) > 1) {
561 // This guy gets used more than once.
562 writeBack = n;
563 }
564 }
565 if (isStaticallyNameable(cls)) {
566 String sig = getInternalName(cls);
567 mv.visitTypeInsn(Opcodes.CHECKCAST, sig);
568 } else {
569 mv.visitLdcInsn(constantPlaceholder(cls));
570 mv.visitTypeInsn(Opcodes.CHECKCAST, CLS);
571 mv.visitInsn(Opcodes.SWAP);
572 mv.visitMethodInsn(Opcodes.INVOKESTATIC, MHI, "castReference", CLL_SIG, false);
573 if (Object[].class.isAssignableFrom(cls))
574 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJARY);
575 else if (PROFILE_LEVEL > 0)
576 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJ);
577 }
578 if (writeBack != null) {
579 mv.visitInsn(Opcodes.DUP);
580 emitAstoreInsn(writeBack.index());
581 }
582 }
583
584 /**
585 * Emits an actual return instruction conforming to the given return type.
586 */
587 private void emitReturnInsn(BasicType type) {
588 int opcode;
589 switch (type) {
590 case I_TYPE: opcode = Opcodes.IRETURN; break;
591 case J_TYPE: opcode = Opcodes.LRETURN; break;
592 case F_TYPE: opcode = Opcodes.FRETURN; break;
593 case D_TYPE: opcode = Opcodes.DRETURN; break;
594 case L_TYPE: opcode = Opcodes.ARETURN; break;
595 case V_TYPE: opcode = Opcodes.RETURN; break;
596 default:
597 throw new InternalError("unknown return type: " + type);
598 }
599 mv.visitInsn(opcode);
600 }
601
602 private static String getInternalName(Class<?> c) {
603 if (c == Object.class) return OBJ;
604 else if (c == Object[].class) return OBJARY;
605 else if (c == Class.class) return CLS;
606 else if (c == MethodHandle.class) return MH;
607 assert(VerifyAccess.isTypeVisible(c, Object.class)) : c.getName();
608 return c.getName().replace('.', '/');
609 }
610
611 /**
612 * Generate customized bytecode for a given LambdaForm.
613 */
614 static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) {
615 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("MH", form, invokerType);
616 return g.loadMethod(g.generateCustomizedCodeBytes());
617 }
618
619 /** Determines whether a LambdaForm being compiled contains an intrinsic of some particular type. */
620 private boolean containsIntrinsic(MethodHandleImpl.Intrinsic intr) {
621 for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) {
622 Name name = lambdaForm.names[i];
623 if (name.function.intrinsicName() == intr) {
624 return true;
625 }
626 }
627 return false;
628 }
629
630 /**
631 * Generate an invoker method for the passed {@link LambdaForm}.
632 */
633 private byte[] generateCustomizedCodeBytes() {
634 classFilePrologue();
635
636 // Suppress this method in backtraces displayed to the user.
637 mv.visitAnnotation("Ljava/lang/invoke/LambdaForm$Hidden;", true);
638
639 // Mark this method as a compiled LambdaForm
640 mv.visitAnnotation("Ljava/lang/invoke/LambdaForm$Compiled;", true);
641
642 if (PROFILE_GWT && containsIntrinsic(MethodHandleImpl.Intrinsic.SELECT_ALTERNATIVE)) {
643 // For now, mark only GWT LambdaForms as @Shared.
644 // TODO: consider marking other non-customized LambdaForms as @Shared
645 mv.visitAnnotation("Ljava/lang/invoke/LambdaForm$Shared;", true);
646 }
647
648 if (lambdaForm.forceInline) {
649 // Force inlining of this invoker method.
650 mv.visitAnnotation("Ljava/lang/invoke/ForceInline;", true);
651 } else {
652 mv.visitAnnotation("Ljava/lang/invoke/DontInline;", true);
653 }
654
655 // iterate over the form's names, generating bytecode instructions for each
656 // start iterating at the first name following the arguments
657 Name onStack = null;
658 for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) {
659 Name name = lambdaForm.names[i];
660
661 emitStoreResult(onStack);
662 onStack = name; // unless otherwise modified below
663 MethodHandleImpl.Intrinsic intr = name.function.intrinsicName();
664 switch (intr) {
665 case SELECT_ALTERNATIVE:
666 assert isSelectAlternative(i);
667 onStack = emitSelectAlternative(name, lambdaForm.names[i+1]);
668 i++; // skip MH.invokeBasic of the selectAlternative result
669 continue;
670 case GUARD_WITH_CATCH:
671 assert isGuardWithCatch(i);
672 onStack = emitGuardWithCatch(i);
673 i = i+2; // Jump to the end of GWC idiom
674 continue;
675 case NEW_ARRAY:
676 Class<?> rtype = name.function.methodType().returnType();
677 if (isStaticallyNameable(rtype)) {
678 emitNewArray(name);
679 continue;
680 }
681 break;
682 case ARRAY_LOAD:
683 emitArrayLoad(name);
684 continue;
685 case ARRAY_STORE:
686 emitArrayStore(name);
687 continue;
688 case IDENTITY:
689 assert(name.arguments.length == 1);
690 emitPushArguments(name);
691 continue;
692 case ZERO:
693 assert(name.arguments.length == 0);
694 emitConst(name.type.basicTypeWrapper().zero());
695 continue;
696 case NONE:
697 // no intrinsic associated
698 break;
699 default:
700 throw newInternalError("Unknown intrinsic: "+intr);
701 }
702
703 MemberName member = name.function.member();
704 if (isStaticallyInvocable(member)) {
705 emitStaticInvoke(member, name);
706 } else {
707 emitInvoke(name);
708 }
709 }
710
711 // return statement
712 emitReturn(onStack);
713
714 classFileEpilogue();
715 bogusMethod(lambdaForm);
716
717 final byte[] classFile = cw.toByteArray();
718 maybeDump(className, classFile);
719 return classFile;
720 }
721
722 void emitArrayLoad(Name name) { emitArrayOp(name, Opcodes.AALOAD); }
723 void emitArrayStore(Name name) { emitArrayOp(name, Opcodes.AASTORE); }
724
725 void emitArrayOp(Name name, int arrayOpcode) {
726 assert arrayOpcode == Opcodes.AALOAD || arrayOpcode == Opcodes.AASTORE;
727 Class<?> elementType = name.function.methodType().parameterType(0).getComponentType();
728 assert elementType != null;
729 emitPushArguments(name);
730 if (elementType.isPrimitive()) {
731 Wrapper w = Wrapper.forPrimitiveType(elementType);
732 arrayOpcode = arrayInsnOpcode(arrayTypeCode(w), arrayOpcode);
733 }
734 mv.visitInsn(arrayOpcode);
735 }
736
737 /**
738 * Emit an invoke for the given name.
739 */
740 void emitInvoke(Name name) {
741 assert(!isLinkerMethodInvoke(name)); // should use the static path for these
742 if (true) {
743 // push receiver
744 MethodHandle target = name.function.resolvedHandle;
745 assert(target != null) : name.exprString();
746 mv.visitLdcInsn(constantPlaceholder(target));
747 emitReferenceCast(MethodHandle.class, target);
748 } else {
749 // load receiver
750 emitAloadInsn(0);
751 emitReferenceCast(MethodHandle.class, null);
752 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", LF_SIG);
753 mv.visitFieldInsn(Opcodes.GETFIELD, LF, "names", LFN_SIG);
754 // TODO more to come
755 }
756
757 // push arguments
758 emitPushArguments(name);
759
760 // invocation
761 MethodType type = name.function.methodType();
762 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
763 }
764
765 static private Class<?>[] STATICALLY_INVOCABLE_PACKAGES = {
766 // Sample classes from each package we are willing to bind to statically:
767 java.lang.Object.class,
768 java.util.Arrays.class,
769 sun.misc.Unsafe.class
770 //MethodHandle.class already covered
771 };
772
773 static boolean isStaticallyInvocable(Name name) {
774 return isStaticallyInvocable(name.function.member());
775 }
776
777 static boolean isStaticallyInvocable(MemberName member) {
778 if (member == null) return false;
779 if (member.isConstructor()) return false;
780 Class<?> cls = member.getDeclaringClass();
781 if (cls.isArray() || cls.isPrimitive())
782 return false; // FIXME
783 if (cls.isAnonymousClass() || cls.isLocalClass())
784 return false; // inner class of some sort
785 if (cls.getClassLoader() != MethodHandle.class.getClassLoader())
786 return false; // not on BCP
787 if (ReflectUtil.isVMAnonymousClass(cls)) // FIXME: switch to supported API once it is added
788 return false;
789 MethodType mtype = member.getMethodOrFieldType();
790 if (!isStaticallyNameable(mtype.returnType()))
791 return false;
792 for (Class<?> ptype : mtype.parameterArray())
793 if (!isStaticallyNameable(ptype))
794 return false;
795 if (!member.isPrivate() && VerifyAccess.isSamePackage(MethodHandle.class, cls))
796 return true; // in java.lang.invoke package
797 if (member.isPublic() && isStaticallyNameable(cls))
798 return true;
799 return false;
800 }
801
802 static boolean isStaticallyNameable(Class<?> cls) {
803 if (cls == Object.class)
804 return true;
805 while (cls.isArray())
806 cls = cls.getComponentType();
807 if (cls.isPrimitive())
808 return true; // int[].class, for example
809 if (ReflectUtil.isVMAnonymousClass(cls)) // FIXME: switch to supported API once it is added
810 return false;
811 // could use VerifyAccess.isClassAccessible but the following is a safe approximation
812 if (cls.getClassLoader() != Object.class.getClassLoader())
813 return false;
814 if (VerifyAccess.isSamePackage(MethodHandle.class, cls))
815 return true;
816 if (!Modifier.isPublic(cls.getModifiers()))
817 return false;
818 for (Class<?> pkgcls : STATICALLY_INVOCABLE_PACKAGES) {
819 if (VerifyAccess.isSamePackage(pkgcls, cls))
820 return true;
821 }
822 return false;
823 }
824
825 void emitStaticInvoke(Name name) {
826 emitStaticInvoke(name.function.member(), name);
827 }
828
829 /**
830 * Emit an invoke for the given name, using the MemberName directly.
831 */
832 void emitStaticInvoke(MemberName member, Name name) {
833 assert(member.equals(name.function.member()));
834 Class<?> defc = member.getDeclaringClass();
835 String cname = getInternalName(defc);
836 String mname = member.getName();
837 String mtype;
838 byte refKind = member.getReferenceKind();
839 if (refKind == REF_invokeSpecial) {
840 // in order to pass the verifier, we need to convert this to invokevirtual in all cases
841 assert(member.canBeStaticallyBound()) : member;
842 refKind = REF_invokeVirtual;
843 }
844
845 if (member.getDeclaringClass().isInterface() && refKind == REF_invokeVirtual) {
846 // Methods from Object declared in an interface can be resolved by JVM to invokevirtual kind.
847 // Need to convert it back to invokeinterface to pass verification and make the invocation works as expected.
848 refKind = REF_invokeInterface;
849 }
850
851 // push arguments
852 emitPushArguments(name);
853
854 // invocation
855 if (member.isMethod()) {
856 mtype = member.getMethodType().toMethodDescriptorString();
857 mv.visitMethodInsn(refKindOpcode(refKind), cname, mname, mtype,
858 member.getDeclaringClass().isInterface());
859 } else {
860 mtype = MethodType.toFieldDescriptorString(member.getFieldType());
861 mv.visitFieldInsn(refKindOpcode(refKind), cname, mname, mtype);
862 }
863 // Issue a type assertion for the result, so we can avoid casts later.
864 if (name.type == L_TYPE) {
865 Class<?> rtype = member.getInvocationType().returnType();
866 assert(!rtype.isPrimitive());
867 if (rtype != Object.class && !rtype.isInterface()) {
868 assertStaticType(rtype, name);
869 }
870 }
871 }
872
873 void emitNewArray(Name name) throws InternalError {
874 Class<?> rtype = name.function.methodType().returnType();
875 if (name.arguments.length == 0) {
876 // The array will be a constant.
877 Object emptyArray;
878 try {
879 emptyArray = name.function.resolvedHandle.invoke();
880 } catch (Throwable ex) {
881 throw newInternalError(ex);
882 }
883 assert(java.lang.reflect.Array.getLength(emptyArray) == 0);
884 assert(emptyArray.getClass() == rtype); // exact typing
885 mv.visitLdcInsn(constantPlaceholder(emptyArray));
886 emitReferenceCast(rtype, emptyArray);
887 return;
888 }
889 Class<?> arrayElementType = rtype.getComponentType();
890 assert(arrayElementType != null);
891 emitIconstInsn(name.arguments.length);
892 int xas = Opcodes.AASTORE;
893 if (!arrayElementType.isPrimitive()) {
894 mv.visitTypeInsn(Opcodes.ANEWARRAY, getInternalName(arrayElementType));
895 } else {
896 byte tc = arrayTypeCode(Wrapper.forPrimitiveType(arrayElementType));
897 xas = arrayInsnOpcode(tc, xas);
898 mv.visitIntInsn(Opcodes.NEWARRAY, tc);
899 }
900 // store arguments
901 for (int i = 0; i < name.arguments.length; i++) {
902 mv.visitInsn(Opcodes.DUP);
903 emitIconstInsn(i);
904 emitPushArgument(name, i);
905 mv.visitInsn(xas);
906 }
907 // the array is left on the stack
908 assertStaticType(rtype, name);
909 }
910 int refKindOpcode(byte refKind) {
911 switch (refKind) {
912 case REF_invokeVirtual: return Opcodes.INVOKEVIRTUAL;
913 case REF_invokeStatic: return Opcodes.INVOKESTATIC;
914 case REF_invokeSpecial: return Opcodes.INVOKESPECIAL;
915 case REF_invokeInterface: return Opcodes.INVOKEINTERFACE;
916 case REF_getField: return Opcodes.GETFIELD;
917 case REF_putField: return Opcodes.PUTFIELD;
918 case REF_getStatic: return Opcodes.GETSTATIC;
919 case REF_putStatic: return Opcodes.PUTSTATIC;
920 }
921 throw new InternalError("refKind="+refKind);
922 }
923
924 /**
925 * Check if MemberName is a call to a method named {@code name} in class {@code declaredClass}.
926 */
927 private boolean memberRefersTo(MemberName member, Class<?> declaringClass, String name) {
928 return member != null &&
929 member.getDeclaringClass() == declaringClass &&
930 member.getName().equals(name);
931 }
932 private boolean nameRefersTo(Name name, Class<?> declaringClass, String methodName) {
933 return name.function != null &&
934 memberRefersTo(name.function.member(), declaringClass, methodName);
935 }
936
937 /**
938 * Check if MemberName is a call to MethodHandle.invokeBasic.
939 */
940 private boolean isInvokeBasic(Name name) {
941 if (name.function == null)
942 return false;
943 if (name.arguments.length < 1)
944 return false; // must have MH argument
945 MemberName member = name.function.member();
946 return memberRefersTo(member, MethodHandle.class, "invokeBasic") &&
947 !member.isPublic() && !member.isStatic();
948 }
949
950 /**
951 * Check if MemberName is a call to MethodHandle.linkToStatic, etc.
952 */
953 private boolean isLinkerMethodInvoke(Name name) {
954 if (name.function == null)
955 return false;
956 if (name.arguments.length < 1)
957 return false; // must have MH argument
958 MemberName member = name.function.member();
959 return member != null &&
960 member.getDeclaringClass() == MethodHandle.class &&
961 !member.isPublic() && member.isStatic() &&
962 member.getName().startsWith("linkTo");
963 }
964
965 /**
966 * Check if i-th name is a call to MethodHandleImpl.selectAlternative.
967 */
968 private boolean isSelectAlternative(int pos) {
969 // selectAlternative idiom:
970 // t_{n}:L=MethodHandleImpl.selectAlternative(...)
971 // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
972 if (pos+1 >= lambdaForm.names.length) return false;
973 Name name0 = lambdaForm.names[pos];
974 Name name1 = lambdaForm.names[pos+1];
975 return nameRefersTo(name0, MethodHandleImpl.class, "selectAlternative") &&
976 isInvokeBasic(name1) &&
977 name1.lastUseIndex(name0) == 0 && // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
978 lambdaForm.lastUseIndex(name0) == pos+1; // t_{n} is local: used only in t_{n+1}
979 }
980
981 /**
982 * Check if i-th name is a start of GuardWithCatch idiom.
983 */
984 private boolean isGuardWithCatch(int pos) {
985 // GuardWithCatch idiom:
986 // t_{n}:L=MethodHandle.invokeBasic(...)
987 // t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
988 // t_{n+2}:?=MethodHandle.invokeBasic(t_{n+1})
989 if (pos+2 >= lambdaForm.names.length) return false;
990 Name name0 = lambdaForm.names[pos];
991 Name name1 = lambdaForm.names[pos+1];
992 Name name2 = lambdaForm.names[pos+2];
993 return nameRefersTo(name1, MethodHandleImpl.class, "guardWithCatch") &&
994 isInvokeBasic(name0) &&
995 isInvokeBasic(name2) &&
996 name1.lastUseIndex(name0) == 3 && // t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
997 lambdaForm.lastUseIndex(name0) == pos+1 && // t_{n} is local: used only in t_{n+1}
998 name2.lastUseIndex(name1) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(t_{n+1})
999 lambdaForm.lastUseIndex(name1) == pos+2; // t_{n+1} is local: used only in t_{n+2}
1000 }
1001
1002 /**
1003 * Emit bytecode for the selectAlternative idiom.
1004 *
1005 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithTest):
1006 * <blockquote><pre>{@code
1007 * Lambda(a0:L,a1:I)=>{
1008 * t2:I=foo.test(a1:I);
1009 * t3:L=MethodHandleImpl.selectAlternative(t2:I,(MethodHandle(int)int),(MethodHandle(int)int));
1010 * t4:I=MethodHandle.invokeBasic(t3:L,a1:I);t4:I}
1011 * }</pre></blockquote>
1012 */
1013 private Name emitSelectAlternative(Name selectAlternativeName, Name invokeBasicName) {
1014 assert isStaticallyInvocable(invokeBasicName);
1015
1016 Name receiver = (Name) invokeBasicName.arguments[0];
1017
1018 Label L_fallback = new Label();
1019 Label L_done = new Label();
1020
1021 // load test result
1022 emitPushArgument(selectAlternativeName, 0);
1023
1024 if (PROFILE_GWT) {
1025 emitPushArgument(selectAlternativeName, 3);
1026 mv.visitMethodInsn(Opcodes.INVOKESTATIC, MHI, "profileBranch", "(Z[I)Z", false);
1027 }
1028
1029 // if_icmpne L_fallback
1030 mv.visitJumpInsn(Opcodes.IFEQ, L_fallback);
1031
1032 // invoke selectAlternativeName.arguments[1]
1033 Class<?>[] preForkClasses = localClasses.clone();
1034 emitPushArgument(selectAlternativeName, 1); // get 2nd argument of selectAlternative
1035 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
1036 emitStaticInvoke(invokeBasicName);
1037
1038 // goto L_done
1039 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1040
1041 // L_fallback:
1042 mv.visitLabel(L_fallback);
1043
1044 // invoke selectAlternativeName.arguments[2]
1045 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
1046 emitPushArgument(selectAlternativeName, 2); // get 3rd argument of selectAlternative
1047 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
1048 emitStaticInvoke(invokeBasicName);
1049
1050 // L_done:
1051 mv.visitLabel(L_done);
1052 // for now do not bother to merge typestate; just reset to the dominator state
1053 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
1054
1055 return invokeBasicName; // return what's on stack
1056 }
1057
1058 /**
1059 * Emit bytecode for the guardWithCatch idiom.
1060 *
1061 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithCatch):
1062 * <blockquote><pre>{@code
1063 * guardWithCatch=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{
1064 * t8:L=MethodHandle.invokeBasic(a4:L,a6:L,a7:L);
1065 * t9:L=MethodHandleImpl.guardWithCatch(a1:L,a2:L,a3:L,t8:L);
1066 * t10:I=MethodHandle.invokeBasic(a5:L,t9:L);t10:I}
1067 * }</pre></blockquote>
1068 *
1069 * It is compiled into bytecode equivalent of the following code:
1070 * <blockquote><pre>{@code
1071 * try {
1072 * return a1.invokeBasic(a6, a7);
1073 * } catch (Throwable e) {
1074 * if (!a2.isInstance(e)) throw e;
1075 * return a3.invokeBasic(ex, a6, a7);
1076 * }}
1077 */
1078 private Name emitGuardWithCatch(int pos) {
1079 Name args = lambdaForm.names[pos];
1080 Name invoker = lambdaForm.names[pos+1];
1081 Name result = lambdaForm.names[pos+2];
1082
1083 Label L_startBlock = new Label();
1084 Label L_endBlock = new Label();
1085 Label L_handler = new Label();
1086 Label L_done = new Label();
1087
1088 Class<?> returnType = result.function.resolvedHandle.type().returnType();
1089 MethodType type = args.function.resolvedHandle.type()
1090 .dropParameterTypes(0,1)
1091 .changeReturnType(returnType);
1092
1093 mv.visitTryCatchBlock(L_startBlock, L_endBlock, L_handler, "java/lang/Throwable");
1094
1095 // Normal case
1096 mv.visitLabel(L_startBlock);
1097 // load target
1098 emitPushArgument(invoker, 0);
1099 emitPushArguments(args, 1); // skip 1st argument: method handle
1100 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
1101 mv.visitLabel(L_endBlock);
1102 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1103
1104 // Exceptional case
1105 mv.visitLabel(L_handler);
1106
1107 // Check exception's type
1108 mv.visitInsn(Opcodes.DUP);
1109 // load exception class
1110 emitPushArgument(invoker, 1);
1111 mv.visitInsn(Opcodes.SWAP);
1112 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Class", "isInstance", "(Ljava/lang/Object;)Z", false);
1113 Label L_rethrow = new Label();
1114 mv.visitJumpInsn(Opcodes.IFEQ, L_rethrow);
1115
1116 // Invoke catcher
1117 // load catcher
1118 emitPushArgument(invoker, 2);
1119 mv.visitInsn(Opcodes.SWAP);
1120 emitPushArguments(args, 1); // skip 1st argument: method handle
1121 MethodType catcherType = type.insertParameterTypes(0, Throwable.class);
1122 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", catcherType.basicType().toMethodDescriptorString(), false);
1123 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1124
1125 mv.visitLabel(L_rethrow);
1126 mv.visitInsn(Opcodes.ATHROW);
1127
1128 mv.visitLabel(L_done);
1129
1130 return result;
1131 }
1132
1133 private void emitPushArguments(Name args) {
1134 emitPushArguments(args, 0);
1135 }
1136
1137 private void emitPushArguments(Name args, int start) {
1138 for (int i = start; i < args.arguments.length; i++) {
1139 emitPushArgument(args, i);
1140 }
1141 }
1142
1143 private void emitPushArgument(Name name, int paramIndex) {
1144 Object arg = name.arguments[paramIndex];
1145 Class<?> ptype = name.function.methodType().parameterType(paramIndex);
1146 emitPushArgument(ptype, arg);
1147 }
1148
1149 private void emitPushArgument(Class<?> ptype, Object arg) {
1150 BasicType bptype = basicType(ptype);
1151 if (arg instanceof Name) {
1152 Name n = (Name) arg;
1153 emitLoadInsn(n.type, n.index());
1154 emitImplicitConversion(n.type, ptype, n);
1155 } else if ((arg == null || arg instanceof String) && bptype == L_TYPE) {
1156 emitConst(arg);
1157 } else {
1158 if (Wrapper.isWrapperType(arg.getClass()) && bptype != L_TYPE) {
1159 emitConst(arg);
1160 } else {
1161 mv.visitLdcInsn(constantPlaceholder(arg));
1162 emitImplicitConversion(L_TYPE, ptype, arg);
1163 }
1164 }
1165 }
1166
1167 /**
1168 * Store the name to its local, if necessary.
1169 */
1170 private void emitStoreResult(Name name) {
1171 if (name != null && name.type != V_TYPE) {
1172 // non-void: actually assign
1173 emitStoreInsn(name.type, name.index());
1174 }
1175 }
1176
1177 /**
1178 * Emits a return statement from a LF invoker. If required, the result type is cast to the correct return type.
1179 */
1180 private void emitReturn(Name onStack) {
1181 // return statement
1182 Class<?> rclass = invokerType.returnType();
1183 BasicType rtype = lambdaForm.returnType();
1184 assert(rtype == basicType(rclass)); // must agree
1185 if (rtype == V_TYPE) {
1186 // void
1187 mv.visitInsn(Opcodes.RETURN);
1188 // it doesn't matter what rclass is; the JVM will discard any value
1189 } else {
1190 LambdaForm.Name rn = lambdaForm.names[lambdaForm.result];
1191
1192 // put return value on the stack if it is not already there
1193 if (rn != onStack) {
1194 emitLoadInsn(rtype, lambdaForm.result);
1195 }
1196
1197 emitImplicitConversion(rtype, rclass, rn);
1198
1199 // generate actual return statement
1200 emitReturnInsn(rtype);
1201 }
1202 }
1203
1204 /**
1205 * Emit a type conversion bytecode casting from "from" to "to".
1206 */
1207 private void emitPrimCast(Wrapper from, Wrapper to) {
1208 // Here's how.
1209 // - indicates forbidden
1210 // <-> indicates implicit
1211 // to ----> boolean byte short char int long float double
1212 // from boolean <-> - - - - - - -
1213 // byte - <-> i2s i2c <-> i2l i2f i2d
1214 // short - i2b <-> i2c <-> i2l i2f i2d
1215 // char - i2b i2s <-> <-> i2l i2f i2d
1216 // int - i2b i2s i2c <-> i2l i2f i2d
1217 // long - l2i,i2b l2i,i2s l2i,i2c l2i <-> l2f l2d
1218 // float - f2i,i2b f2i,i2s f2i,i2c f2i f2l <-> f2d
1219 // double - d2i,i2b d2i,i2s d2i,i2c d2i d2l d2f <->
1220 if (from == to) {
1221 // no cast required, should be dead code anyway
1222 return;
1223 }
1224 if (from.isSubwordOrInt()) {
1225 // cast from {byte,short,char,int} to anything
1226 emitI2X(to);
1227 } else {
1228 // cast from {long,float,double} to anything
1229 if (to.isSubwordOrInt()) {
1230 // cast to {byte,short,char,int}
1231 emitX2I(from);
1232 if (to.bitWidth() < 32) {
1233 // targets other than int require another conversion
1234 emitI2X(to);
1235 }
1236 } else {
1237 // cast to {long,float,double} - this is verbose
1238 boolean error = false;
1239 switch (from) {
1240 case LONG:
1241 switch (to) {
1242 case FLOAT: mv.visitInsn(Opcodes.L2F); break;
1243 case DOUBLE: mv.visitInsn(Opcodes.L2D); break;
1244 default: error = true; break;
1245 }
1246 break;
1247 case FLOAT:
1248 switch (to) {
1249 case LONG : mv.visitInsn(Opcodes.F2L); break;
1250 case DOUBLE: mv.visitInsn(Opcodes.F2D); break;
1251 default: error = true; break;
1252 }
1253 break;
1254 case DOUBLE:
1255 switch (to) {
1256 case LONG : mv.visitInsn(Opcodes.D2L); break;
1257 case FLOAT: mv.visitInsn(Opcodes.D2F); break;
1258 default: error = true; break;
1259 }
1260 break;
1261 default:
1262 error = true;
1263 break;
1264 }
1265 if (error) {
1266 throw new IllegalStateException("unhandled prim cast: " + from + "2" + to);
1267 }
1268 }
1269 }
1270 }
1271
1272 private void emitI2X(Wrapper type) {
1273 switch (type) {
1274 case BYTE: mv.visitInsn(Opcodes.I2B); break;
1275 case SHORT: mv.visitInsn(Opcodes.I2S); break;
1276 case CHAR: mv.visitInsn(Opcodes.I2C); break;
1277 case INT: /* naught */ break;
1278 case LONG: mv.visitInsn(Opcodes.I2L); break;
1279 case FLOAT: mv.visitInsn(Opcodes.I2F); break;
1280 case DOUBLE: mv.visitInsn(Opcodes.I2D); break;
1281 case BOOLEAN:
1282 // For compatibility with ValueConversions and explicitCastArguments:
1283 mv.visitInsn(Opcodes.ICONST_1);
1284 mv.visitInsn(Opcodes.IAND);
1285 break;
1286 default: throw new InternalError("unknown type: " + type);
1287 }
1288 }
1289
1290 private void emitX2I(Wrapper type) {
1291 switch (type) {
1292 case LONG: mv.visitInsn(Opcodes.L2I); break;
1293 case FLOAT: mv.visitInsn(Opcodes.F2I); break;
1294 case DOUBLE: mv.visitInsn(Opcodes.D2I); break;
1295 default: throw new InternalError("unknown type: " + type);
1296 }
1297 }
1298
1299 /**
1300 * Generate bytecode for a LambdaForm.vmentry which calls interpretWithArguments.
1301 */
1302 static MemberName generateLambdaFormInterpreterEntryPoint(String sig) {
1303 assert(isValidSignature(sig));
1304 String name = "interpret_"+signatureReturn(sig).basicTypeChar();
1305 MethodType type = signatureType(sig); // sig includes leading argument
1306 type = type.changeParameterType(0, MethodHandle.class);
1307 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("LFI", name, type);
1308 return g.loadMethod(g.generateLambdaFormInterpreterEntryPointBytes());
1309 }
1310
1311 private byte[] generateLambdaFormInterpreterEntryPointBytes() {
1312 classFilePrologue();
1313
1314 // Suppress this method in backtraces displayed to the user.
1315 mv.visitAnnotation("Ljava/lang/invoke/LambdaForm$Hidden;", true);
1316
1317 // Don't inline the interpreter entry.
1318 mv.visitAnnotation("Ljava/lang/invoke/DontInline;", true);
1319
1320 // create parameter array
1321 emitIconstInsn(invokerType.parameterCount());
1322 mv.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object");
1323
1324 // fill parameter array
1325 for (int i = 0; i < invokerType.parameterCount(); i++) {
1326 Class<?> ptype = invokerType.parameterType(i);
1327 mv.visitInsn(Opcodes.DUP);
1328 emitIconstInsn(i);
1329 emitLoadInsn(basicType(ptype), i);
1330 // box if primitive type
1331 if (ptype.isPrimitive()) {
1332 emitBoxing(Wrapper.forPrimitiveType(ptype));
1333 }
1334 mv.visitInsn(Opcodes.AASTORE);
1335 }
1336 // invoke
1337 emitAloadInsn(0);
1338 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", "Ljava/lang/invoke/LambdaForm;");
1339 mv.visitInsn(Opcodes.SWAP); // swap form and array; avoid local variable
1340 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, LF, "interpretWithArguments", "([Ljava/lang/Object;)Ljava/lang/Object;", false);
1341
1342 // maybe unbox
1343 Class<?> rtype = invokerType.returnType();
1344 if (rtype.isPrimitive() && rtype != void.class) {
1345 emitUnboxing(Wrapper.forPrimitiveType(rtype));
1346 }
1347
1348 // return statement
1349 emitReturnInsn(basicType(rtype));
1350
1351 classFileEpilogue();
1352 bogusMethod(invokerType);
1353
1354 final byte[] classFile = cw.toByteArray();
1355 maybeDump(className, classFile);
1356 return classFile;
1357 }
1358
1359 /**
1360 * Generate bytecode for a NamedFunction invoker.
1361 */
1362 static MemberName generateNamedFunctionInvoker(MethodTypeForm typeForm) {
1363 MethodType invokerType = NamedFunction.INVOKER_METHOD_TYPE;
1364 String invokerName = "invoke_" + shortenSignature(basicTypeSignature(typeForm.erasedType()));
1365 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("NFI", invokerName, invokerType);
1366 return g.loadMethod(g.generateNamedFunctionInvokerImpl(typeForm));
1367 }
1368
1369 private byte[] generateNamedFunctionInvokerImpl(MethodTypeForm typeForm) {
1370 MethodType dstType = typeForm.erasedType();
1371 classFilePrologue();
1372
1373 // Suppress this method in backtraces displayed to the user.
1374 mv.visitAnnotation("Ljava/lang/invoke/LambdaForm$Hidden;", true);
1375
1376 // Force inlining of this invoker method.
1377 mv.visitAnnotation("Ljava/lang/invoke/ForceInline;", true);
1378
1379 // Load receiver
1380 emitAloadInsn(0);
1381
1382 // Load arguments from array
1383 for (int i = 0; i < dstType.parameterCount(); i++) {
1384 emitAloadInsn(1);
1385 emitIconstInsn(i);
1386 mv.visitInsn(Opcodes.AALOAD);
1387
1388 // Maybe unbox
1389 Class<?> dptype = dstType.parameterType(i);
1390 if (dptype.isPrimitive()) {
1391 Class<?> sptype = dstType.basicType().wrap().parameterType(i);
1392 Wrapper dstWrapper = Wrapper.forBasicType(dptype);
1393 Wrapper srcWrapper = dstWrapper.isSubwordOrInt() ? Wrapper.INT : dstWrapper; // narrow subword from int
1394 emitUnboxing(srcWrapper);
1395 emitPrimCast(srcWrapper, dstWrapper);
1396 }
1397 }
1398
1399 // Invoke
1400 String targetDesc = dstType.basicType().toMethodDescriptorString();
1401 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", targetDesc, false);
1402
1403 // Box primitive types
1404 Class<?> rtype = dstType.returnType();
1405 if (rtype != void.class && rtype.isPrimitive()) {
1406 Wrapper srcWrapper = Wrapper.forBasicType(rtype);
1407 Wrapper dstWrapper = srcWrapper.isSubwordOrInt() ? Wrapper.INT : srcWrapper; // widen subword to int
1408 // boolean casts not allowed
1409 emitPrimCast(srcWrapper, dstWrapper);
1410 emitBoxing(dstWrapper);
1411 }
1412
1413 // If the return type is void we return a null reference.
1414 if (rtype == void.class) {
1415 mv.visitInsn(Opcodes.ACONST_NULL);
1416 }
1417 emitReturnInsn(L_TYPE); // NOTE: NamedFunction invokers always return a reference value.
1418
1419 classFileEpilogue();
1420 bogusMethod(dstType);
1421
1422 final byte[] classFile = cw.toByteArray();
1423 maybeDump(className, classFile);
1424 return classFile;
1425 }
1426
1427 /**
1428 * Emit a bogus method that just loads some string constants. This is to get the constants into the constant pool
1429 * for debugging purposes.
1430 */
1431 private void bogusMethod(Object... os) {
1432 if (DUMP_CLASS_FILES) {
1433 mv = cw.visitMethod(Opcodes.ACC_STATIC, "dummy", "()V", null, null);
1434 for (Object o : os) {
1435 mv.visitLdcInsn(o.toString());
1436 mv.visitInsn(Opcodes.POP);
1437 }
1438 mv.visitInsn(Opcodes.RETURN);
1439 mv.visitMaxs(0, 0);
1440 mv.visitEnd();
1441 }
1442 }
1443 }