1 /* 2 * Copyright (c) 2012, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.lang.invoke; 27 28 import jdk.internal.org.objectweb.asm.ClassWriter; 29 import jdk.internal.org.objectweb.asm.Label; 30 import jdk.internal.org.objectweb.asm.MethodVisitor; 31 import jdk.internal.org.objectweb.asm.Opcodes; 32 import jdk.internal.org.objectweb.asm.Type; 33 import sun.invoke.util.VerifyAccess; 34 import sun.invoke.util.VerifyType; 35 import sun.invoke.util.Wrapper; 36 import sun.reflect.misc.ReflectUtil; 37 38 import java.io.File; 39 import java.io.FileOutputStream; 40 import java.io.IOException; 41 import java.lang.reflect.Modifier; 42 import java.util.Arrays; 43 import java.util.ArrayList; 44 import java.util.HashMap; 45 import java.util.stream.Stream; 46 47 import static java.lang.invoke.LambdaForm.*; 48 import static java.lang.invoke.LambdaForm.BasicType.*; 49 import static java.lang.invoke.LambdaForm.Kind.*; 50 import static java.lang.invoke.MethodHandleNatives.Constants.*; 51 import static java.lang.invoke.MethodHandleStatics.*; 52 53 /** 54 * Code generation backend for LambdaForm. 55 * <p> 56 * @author John Rose, JSR 292 EG 57 */ 58 class InvokerBytecodeGenerator { 59 /** Define class names for convenience. */ 60 private static final String MH = "java/lang/invoke/MethodHandle"; 61 private static final String MHI = "java/lang/invoke/MethodHandleImpl"; 62 private static final String LF = "java/lang/invoke/LambdaForm"; 63 private static final String LFN = "java/lang/invoke/LambdaForm$Name"; 64 private static final String CLS = "java/lang/Class"; 65 private static final String OBJ = "java/lang/Object"; 66 private static final String OBJARY = "[Ljava/lang/Object;"; 67 68 private static final String LF_SIG = "L" + LF + ";"; 69 private static final String LFN_SIG = "L" + LFN + ";"; 70 private static final String LL_SIG = "(L" + OBJ + ";)L" + OBJ + ";"; 71 private static final String LLV_SIG = "(L" + OBJ + ";L" + OBJ + ";)V"; 72 private static final String CLASS_PREFIX = LF + "$"; 73 74 /** Name of its super class*/ 75 static final String INVOKER_SUPER_NAME = OBJ; 76 77 /** Name of new class */ 78 private final String className; 79 80 /** Name of the source file (for stack trace printing). */ 81 private final String sourceFile; 82 83 private final LambdaForm lambdaForm; 84 private final String invokerName; 85 private final MethodType invokerType; 86 87 /** Info about local variables in compiled lambda form */ 88 private int[] localsMap; // index 89 private Class<?>[] localClasses; // type 90 91 /** ASM bytecode generation. */ 92 private ClassWriter cw; 93 private MethodVisitor mv; 94 95 private static final MemberName.Factory MEMBERNAME_FACTORY = MemberName.getFactory(); 96 private static final Class<?> HOST_CLASS = LambdaForm.class; 97 98 /** Main constructor; other constructors delegate to this one. */ 99 private InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize, 100 String className, String invokerName, MethodType invokerType) { 101 int p = invokerName.indexOf('.'); 102 if (p > -1) { 103 className = invokerName.substring(0, p); 104 invokerName = invokerName.substring(p + 1); 105 } 106 if (DUMP_CLASS_FILES) { 107 className = makeDumpableClassName(className); 108 } 109 this.className = CLASS_PREFIX + className; 110 this.sourceFile = "LambdaForm$" + className; 111 this.lambdaForm = lambdaForm; 112 this.invokerName = invokerName; 113 this.invokerType = invokerType; 114 this.localsMap = new int[localsMapSize+1]; // last entry of localsMap is count of allocated local slots 115 this.localClasses = new Class<?>[localsMapSize+1]; 116 } 117 118 /** For generating LambdaForm interpreter entry points. */ 119 private InvokerBytecodeGenerator(String className, String invokerName, MethodType invokerType) { 120 this(null, invokerType.parameterCount(), 121 className, invokerName, invokerType); 122 // Create an array to map name indexes to locals indexes. 123 for (int i = 0; i < localsMap.length; i++) { 124 localsMap[i] = invokerType.parameterSlotCount() - invokerType.parameterSlotDepth(i); 125 } 126 } 127 128 /** For generating customized code for a single LambdaForm. */ 129 private InvokerBytecodeGenerator(String className, LambdaForm form, MethodType invokerType) { 130 this(className, form.debugName, form, invokerType); 131 } 132 133 /** For generating customized code for a single LambdaForm. */ 134 InvokerBytecodeGenerator(String className, String invokerName, 135 LambdaForm form, MethodType invokerType) { 136 this(form, form.names.length, 137 className, invokerName, invokerType); 138 // Create an array to map name indexes to locals indexes. 139 Name[] names = form.names; 140 for (int i = 0, index = 0; i < localsMap.length; i++) { 141 localsMap[i] = index; 142 if (i < names.length) { 143 BasicType type = names[i].type(); 144 index += type.basicTypeSlots(); 145 } 146 } 147 } 148 149 /** instance counters for dumped classes */ 150 private static final HashMap<String,Integer> DUMP_CLASS_FILES_COUNTERS; 151 /** debugging flag for saving generated class files */ 152 private static final File DUMP_CLASS_FILES_DIR; 153 154 static { 155 if (DUMP_CLASS_FILES) { 156 DUMP_CLASS_FILES_COUNTERS = new HashMap<>(); 157 try { 158 File dumpDir = new File("DUMP_CLASS_FILES"); 159 if (!dumpDir.exists()) { 160 dumpDir.mkdirs(); 161 } 162 DUMP_CLASS_FILES_DIR = dumpDir; 163 System.out.println("Dumping class files to "+DUMP_CLASS_FILES_DIR+"/..."); 164 } catch (Exception e) { 165 throw newInternalError(e); 166 } 167 } else { 168 DUMP_CLASS_FILES_COUNTERS = null; 169 DUMP_CLASS_FILES_DIR = null; 170 } 171 } 172 173 static void maybeDump(final String className, final byte[] classFile) { 174 if (DUMP_CLASS_FILES) { 175 java.security.AccessController.doPrivileged( 176 new java.security.PrivilegedAction<>() { 177 public Void run() { 178 try { 179 String dumpName = className; 180 //dumpName = dumpName.replace('/', '-'); 181 File dumpFile = new File(DUMP_CLASS_FILES_DIR, dumpName+".class"); 182 System.out.println("dump: " + dumpFile); 183 dumpFile.getParentFile().mkdirs(); 184 FileOutputStream file = new FileOutputStream(dumpFile); 185 file.write(classFile); 186 file.close(); 187 return null; 188 } catch (IOException ex) { 189 throw newInternalError(ex); 190 } 191 } 192 }); 193 } 194 } 195 196 private static String makeDumpableClassName(String className) { 197 Integer ctr; 198 synchronized (DUMP_CLASS_FILES_COUNTERS) { 199 ctr = DUMP_CLASS_FILES_COUNTERS.get(className); 200 if (ctr == null) ctr = 0; 201 DUMP_CLASS_FILES_COUNTERS.put(className, ctr+1); 202 } 203 String sfx = ctr.toString(); 204 while (sfx.length() < 3) 205 sfx = "0"+sfx; 206 className += sfx; 207 return className; 208 } 209 210 class CpPatch { 211 final int index; 212 final Object value; 213 CpPatch(int index, Object value) { 214 this.index = index; 215 this.value = value; 216 } 217 public String toString() { 218 return "CpPatch/index="+index+",value="+value; 219 } 220 } 221 222 private final ArrayList<CpPatch> cpPatches = new ArrayList<>(); 223 224 private int cph = 0; // for counting constant placeholders 225 226 String constantPlaceholder(Object arg) { 227 String cpPlaceholder = "CONSTANT_PLACEHOLDER_" + cph++; 228 if (DUMP_CLASS_FILES) cpPlaceholder += " <<" + debugString(arg) + ">>"; 229 // TODO check if arg is already in the constant pool 230 // insert placeholder in CP and remember the patch 231 int index = cw.newConst((Object) cpPlaceholder); 232 cpPatches.add(new CpPatch(index, arg)); 233 return cpPlaceholder; 234 } 235 236 Object[] cpPatches(byte[] classFile) { 237 int size = getConstantPoolSize(classFile); 238 Object[] res = new Object[size]; 239 for (CpPatch p : cpPatches) { 240 if (p.index >= size) 241 throw new InternalError("in cpool["+size+"]: "+p+"\n"+Arrays.toString(Arrays.copyOf(classFile, 20))); 242 res[p.index] = p.value; 243 } 244 return res; 245 } 246 247 private static String debugString(Object arg) { 248 if (arg instanceof MethodHandle) { 249 MethodHandle mh = (MethodHandle) arg; 250 MemberName member = mh.internalMemberName(); 251 if (member != null) 252 return member.toString(); 253 return mh.debugString(); 254 } 255 return arg.toString(); 256 } 257 258 /** 259 * Extract the number of constant pool entries from a given class file. 260 * 261 * @param classFile the bytes of the class file in question. 262 * @return the number of entries in the constant pool. 263 */ 264 private static int getConstantPoolSize(byte[] classFile) { 265 // The first few bytes: 266 // u4 magic; 267 // u2 minor_version; 268 // u2 major_version; 269 // u2 constant_pool_count; 270 return ((classFile[8] & 0xFF) << 8) | (classFile[9] & 0xFF); 271 } 272 273 /** 274 * Extract the MemberName of a newly-defined method. 275 */ 276 private MemberName loadMethod(byte[] classFile) { 277 Class<?> invokerClass = loadAndInitializeInvokerClass(classFile, cpPatches(classFile)); 278 return resolveInvokerMember(invokerClass, invokerName, invokerType); 279 } 280 281 /** 282 * Define a given class as anonymous class in the runtime system. 283 */ 284 private static Class<?> loadAndInitializeInvokerClass(byte[] classBytes, Object[] patches) { 285 Class<?> invokerClass = UNSAFE.defineAnonymousClass(HOST_CLASS, classBytes, patches); 286 UNSAFE.ensureClassInitialized(invokerClass); // Make sure the class is initialized; VM might complain. 287 return invokerClass; 288 } 289 290 private static MemberName resolveInvokerMember(Class<?> invokerClass, String name, MethodType type) { 291 MemberName member = new MemberName(invokerClass, name, type, REF_invokeStatic); 292 try { 293 member = MEMBERNAME_FACTORY.resolveOrFail(REF_invokeStatic, member, HOST_CLASS, ReflectiveOperationException.class); 294 } catch (ReflectiveOperationException e) { 295 throw newInternalError(e); 296 } 297 return member; 298 } 299 300 /** 301 * Set up class file generation. 302 */ 303 private ClassWriter 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, INVOKER_SUPER_NAME, null); 307 cw.visitSource(sourceFile, null); 308 return cw; 309 } 310 311 private void methodPrologue() { 312 String invokerDesc = invokerType.toMethodDescriptorString(); 313 mv = cw.visitMethod(Opcodes.ACC_STATIC, invokerName, invokerDesc, null, null); 314 } 315 316 /** 317 * Tear down class file generation. 318 */ 319 private void methodEpilogue() { 320 mv.visitMaxs(0, 0); 321 mv.visitEnd(); 322 } 323 324 /* 325 * Low-level emit helpers. 326 */ 327 private void emitConst(Object con) { 328 if (con == null) { 329 mv.visitInsn(Opcodes.ACONST_NULL); 330 return; 331 } 332 if (con instanceof Integer) { 333 emitIconstInsn((int) con); 334 return; 335 } 336 if (con instanceof Byte) { 337 emitIconstInsn((byte)con); 338 return; 339 } 340 if (con instanceof Short) { 341 emitIconstInsn((short)con); 342 return; 343 } 344 if (con instanceof Character) { 345 emitIconstInsn((char)con); 346 return; 347 } 348 if (con instanceof Long) { 349 long x = (long) con; 350 short sx = (short)x; 351 if (x == sx) { 352 if (sx >= 0 && sx <= 1) { 353 mv.visitInsn(Opcodes.LCONST_0 + (int) sx); 354 } else { 355 emitIconstInsn((int) x); 356 mv.visitInsn(Opcodes.I2L); 357 } 358 return; 359 } 360 } 361 if (con instanceof Float) { 362 float x = (float) con; 363 short sx = (short)x; 364 if (x == sx) { 365 if (sx >= 0 && sx <= 2) { 366 mv.visitInsn(Opcodes.FCONST_0 + (int) sx); 367 } else { 368 emitIconstInsn((int) x); 369 mv.visitInsn(Opcodes.I2F); 370 } 371 return; 372 } 373 } 374 if (con instanceof Double) { 375 double x = (double) con; 376 short sx = (short)x; 377 if (x == sx) { 378 if (sx >= 0 && sx <= 1) { 379 mv.visitInsn(Opcodes.DCONST_0 + (int) sx); 380 } else { 381 emitIconstInsn((int) x); 382 mv.visitInsn(Opcodes.I2D); 383 } 384 return; 385 } 386 } 387 if (con instanceof Boolean) { 388 emitIconstInsn((boolean) con ? 1 : 0); 389 return; 390 } 391 // fall through: 392 mv.visitLdcInsn(con); 393 } 394 395 private void emitIconstInsn(final int cst) { 396 if (cst >= -1 && cst <= 5) { 397 mv.visitInsn(Opcodes.ICONST_0 + cst); 398 } else if (cst >= Byte.MIN_VALUE && cst <= Byte.MAX_VALUE) { 399 mv.visitIntInsn(Opcodes.BIPUSH, cst); 400 } else if (cst >= Short.MIN_VALUE && cst <= Short.MAX_VALUE) { 401 mv.visitIntInsn(Opcodes.SIPUSH, cst); 402 } else { 403 mv.visitLdcInsn(cst); 404 } 405 } 406 407 /* 408 * NOTE: These load/store methods use the localsMap to find the correct index! 409 */ 410 private void emitLoadInsn(BasicType type, int index) { 411 int opcode = loadInsnOpcode(type); 412 mv.visitVarInsn(opcode, localsMap[index]); 413 } 414 415 private int loadInsnOpcode(BasicType type) throws InternalError { 416 switch (type) { 417 case I_TYPE: return Opcodes.ILOAD; 418 case J_TYPE: return Opcodes.LLOAD; 419 case F_TYPE: return Opcodes.FLOAD; 420 case D_TYPE: return Opcodes.DLOAD; 421 case L_TYPE: return Opcodes.ALOAD; 422 default: 423 throw new InternalError("unknown type: " + type); 424 } 425 } 426 private void emitAloadInsn(int index) { 427 emitLoadInsn(L_TYPE, index); 428 } 429 430 private void emitStoreInsn(BasicType type, int index) { 431 int opcode = storeInsnOpcode(type); 432 mv.visitVarInsn(opcode, localsMap[index]); 433 } 434 435 private int storeInsnOpcode(BasicType type) throws InternalError { 436 switch (type) { 437 case I_TYPE: return Opcodes.ISTORE; 438 case J_TYPE: return Opcodes.LSTORE; 439 case F_TYPE: return Opcodes.FSTORE; 440 case D_TYPE: return Opcodes.DSTORE; 441 case L_TYPE: return Opcodes.ASTORE; 442 default: 443 throw new InternalError("unknown type: " + type); 444 } 445 } 446 private void emitAstoreInsn(int index) { 447 emitStoreInsn(L_TYPE, index); 448 } 449 450 private byte arrayTypeCode(Wrapper elementType) { 451 switch (elementType) { 452 case BOOLEAN: return Opcodes.T_BOOLEAN; 453 case BYTE: return Opcodes.T_BYTE; 454 case CHAR: return Opcodes.T_CHAR; 455 case SHORT: return Opcodes.T_SHORT; 456 case INT: return Opcodes.T_INT; 457 case LONG: return Opcodes.T_LONG; 458 case FLOAT: return Opcodes.T_FLOAT; 459 case DOUBLE: return Opcodes.T_DOUBLE; 460 case OBJECT: return 0; // in place of Opcodes.T_OBJECT 461 default: throw new InternalError(); 462 } 463 } 464 465 private int arrayInsnOpcode(byte tcode, int aaop) throws InternalError { 466 assert(aaop == Opcodes.AASTORE || aaop == Opcodes.AALOAD); 467 int xas; 468 switch (tcode) { 469 case Opcodes.T_BOOLEAN: xas = Opcodes.BASTORE; break; 470 case Opcodes.T_BYTE: xas = Opcodes.BASTORE; break; 471 case Opcodes.T_CHAR: xas = Opcodes.CASTORE; break; 472 case Opcodes.T_SHORT: xas = Opcodes.SASTORE; break; 473 case Opcodes.T_INT: xas = Opcodes.IASTORE; break; 474 case Opcodes.T_LONG: xas = Opcodes.LASTORE; break; 475 case Opcodes.T_FLOAT: xas = Opcodes.FASTORE; break; 476 case Opcodes.T_DOUBLE: xas = Opcodes.DASTORE; break; 477 case 0: xas = Opcodes.AASTORE; break; 478 default: throw new InternalError(); 479 } 480 return xas - Opcodes.AASTORE + aaop; 481 } 482 483 /** 484 * Emit a boxing call. 485 * 486 * @param wrapper primitive type class to box. 487 */ 488 private void emitBoxing(Wrapper wrapper) { 489 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName(); 490 String name = "valueOf"; 491 String desc = "(" + wrapper.basicTypeChar() + ")L" + owner + ";"; 492 mv.visitMethodInsn(Opcodes.INVOKESTATIC, owner, name, desc, false); 493 } 494 495 /** 496 * Emit an unboxing call (plus preceding checkcast). 497 * 498 * @param wrapper wrapper type class to unbox. 499 */ 500 private void emitUnboxing(Wrapper wrapper) { 501 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName(); 502 String name = wrapper.primitiveSimpleName() + "Value"; 503 String desc = "()" + wrapper.basicTypeChar(); 504 emitReferenceCast(wrapper.wrapperType(), null); 505 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, owner, name, desc, false); 506 } 507 508 /** 509 * Emit an implicit conversion for an argument which must be of the given pclass. 510 * This is usually a no-op, except when pclass is a subword type or a reference other than Object or an interface. 511 * 512 * @param ptype type of value present on stack 513 * @param pclass type of value required on stack 514 * @param arg compile-time representation of value on stack (Node, constant) or null if none 515 */ 516 private void emitImplicitConversion(BasicType ptype, Class<?> pclass, Object arg) { 517 assert(basicType(pclass) == ptype); // boxing/unboxing handled by caller 518 if (pclass == ptype.basicTypeClass() && ptype != L_TYPE) 519 return; // nothing to do 520 switch (ptype) { 521 case L_TYPE: 522 if (VerifyType.isNullConversion(Object.class, pclass, false)) { 523 if (PROFILE_LEVEL > 0) 524 emitReferenceCast(Object.class, arg); 525 return; 526 } 527 emitReferenceCast(pclass, arg); 528 return; 529 case I_TYPE: 530 if (!VerifyType.isNullConversion(int.class, pclass, false)) 531 emitPrimCast(ptype.basicTypeWrapper(), Wrapper.forPrimitiveType(pclass)); 532 return; 533 } 534 throw newInternalError("bad implicit conversion: tc="+ptype+": "+pclass); 535 } 536 537 /** Update localClasses type map. Return true if the information is already present. */ 538 private boolean assertStaticType(Class<?> cls, Name n) { 539 int local = n.index(); 540 Class<?> aclass = localClasses[local]; 541 if (aclass != null && (aclass == cls || cls.isAssignableFrom(aclass))) { 542 return true; // type info is already present 543 } else if (aclass == null || aclass.isAssignableFrom(cls)) { 544 localClasses[local] = cls; // type info can be improved 545 } 546 return false; 547 } 548 549 private void emitReferenceCast(Class<?> cls, Object arg) { 550 Name writeBack = null; // local to write back result 551 if (arg instanceof Name) { 552 Name n = (Name) arg; 553 if (lambdaForm.useCount(n) > 1) { 554 // This guy gets used more than once. 555 writeBack = n; 556 if (assertStaticType(cls, n)) { 557 return; // this cast was already performed 558 } 559 } 560 } 561 if (isStaticallyNameable(cls)) { 562 String sig = getInternalName(cls); 563 mv.visitTypeInsn(Opcodes.CHECKCAST, sig); 564 } else { 565 mv.visitLdcInsn(constantPlaceholder(cls)); 566 mv.visitTypeInsn(Opcodes.CHECKCAST, CLS); 567 mv.visitInsn(Opcodes.SWAP); 568 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, CLS, "cast", LL_SIG, false); 569 if (Object[].class.isAssignableFrom(cls)) 570 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJARY); 571 else if (PROFILE_LEVEL > 0) 572 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJ); 573 } 574 if (writeBack != null) { 575 mv.visitInsn(Opcodes.DUP); 576 emitAstoreInsn(writeBack.index()); 577 } 578 } 579 580 /** 581 * Emits an actual return instruction conforming to the given return type. 582 */ 583 private void emitReturnInsn(BasicType type) { 584 int opcode; 585 switch (type) { 586 case I_TYPE: opcode = Opcodes.IRETURN; break; 587 case J_TYPE: opcode = Opcodes.LRETURN; break; 588 case F_TYPE: opcode = Opcodes.FRETURN; break; 589 case D_TYPE: opcode = Opcodes.DRETURN; break; 590 case L_TYPE: opcode = Opcodes.ARETURN; break; 591 case V_TYPE: opcode = Opcodes.RETURN; break; 592 default: 593 throw new InternalError("unknown return type: " + type); 594 } 595 mv.visitInsn(opcode); 596 } 597 598 private static String getInternalName(Class<?> c) { 599 if (c == Object.class) return OBJ; 600 else if (c == Object[].class) return OBJARY; 601 else if (c == Class.class) return CLS; 602 else if (c == MethodHandle.class) return MH; 603 assert(VerifyAccess.isTypeVisible(c, Object.class)) : c.getName(); 604 return c.getName().replace('.', '/'); 605 } 606 607 private static MemberName resolveFrom(String name, MethodType type, Class<?> holder) { 608 MemberName member = new MemberName(holder, name, type, REF_invokeStatic); 609 MemberName resolvedMember = MemberName.getFactory().resolveOrNull(REF_invokeStatic, member, holder); 610 611 return resolvedMember; 612 } 613 614 private static MemberName lookupPregenerated(LambdaForm form) { 615 if (form.customized != null) return null; // No pre-generated version for customized LF 616 MethodType invokerType = form.methodType(); 617 String name = form.kind.methodName; 618 switch (form.kind) { 619 case BOUND_REINVOKER: { 620 name = name + "_" + BoundMethodHandle.speciesData(form).fieldSignature(); 621 return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class); 622 } 623 case DELEGATE: return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class); 624 case DIRECT_INVOKE_INTERFACE: // fall-through 625 case DIRECT_INVOKE_SPECIAL: // fall-through 626 case DIRECT_INVOKE_STATIC: // fall-through 627 case DIRECT_INVOKE_STATIC_INIT: // fall-through 628 case DIRECT_INVOKE_VIRTUAL: return resolveFrom(name, invokerType, DirectMethodHandle.Holder.class); 629 } 630 return null; 631 } 632 633 /** 634 * Generate customized bytecode for a given LambdaForm. 635 */ 636 static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) { 637 MemberName pregenerated = lookupPregenerated(form); 638 if (pregenerated != null) return pregenerated; // pre-generated bytecode 639 640 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("MH", form, invokerType); 641 return g.loadMethod(g.generateCustomizedCodeBytes()); 642 } 643 644 /** Generates code to check that actual receiver and LambdaForm matches */ 645 private boolean checkActualReceiver() { 646 // Expects MethodHandle on the stack and actual receiver MethodHandle in slot #0 647 mv.visitInsn(Opcodes.DUP); 648 mv.visitVarInsn(Opcodes.ALOAD, localsMap[0]); 649 mv.visitMethodInsn(Opcodes.INVOKESTATIC, MHI, "assertSame", LLV_SIG, false); 650 return true; 651 } 652 653 static String className(String cn) { 654 assert checkClassName(cn): "Class not found: " + cn; 655 return cn; 656 } 657 658 static boolean checkClassName(String cn) { 659 Type tp = Type.getType(cn); 660 // additional sanity so only valid "L;" descriptors work 661 if (tp.getSort() != Type.OBJECT) { 662 return false; 663 } 664 try { 665 Class<?> c = Class.forName(tp.getClassName(), false, null); 666 return true; 667 } catch (ClassNotFoundException e) { 668 return false; 669 } 670 } 671 672 static final String LF_HIDDEN_SIG = className("Ljava/lang/invoke/LambdaForm$Hidden;"); 673 static final String LF_COMPILED_SIG = className("Ljava/lang/invoke/LambdaForm$Compiled;"); 674 static final String FORCEINLINE_SIG = className("Ljdk/internal/vm/annotation/ForceInline;"); 675 static final String DONTINLINE_SIG = className("Ljdk/internal/vm/annotation/DontInline;"); 676 static final String INJECTEDPROFILE_SIG = className("Ljava/lang/invoke/InjectedProfile;"); 677 678 /** 679 * Generate an invoker method for the passed {@link LambdaForm}. 680 */ 681 private byte[] generateCustomizedCodeBytes() { 682 classFilePrologue(); 683 addMethod(); 684 bogusMethod(lambdaForm); 685 686 final byte[] classFile = toByteArray(); 687 maybeDump(className, classFile); 688 return classFile; 689 } 690 691 void setClassWriter(ClassWriter cw) { 692 this.cw = cw; 693 } 694 695 void addMethod() { 696 methodPrologue(); 697 698 // Suppress this method in backtraces displayed to the user. 699 mv.visitAnnotation(LF_HIDDEN_SIG, true); 700 701 // Mark this method as a compiled LambdaForm 702 mv.visitAnnotation(LF_COMPILED_SIG, true); 703 704 if (lambdaForm.forceInline) { 705 // Force inlining of this invoker method. 706 mv.visitAnnotation(FORCEINLINE_SIG, true); 707 } else { 708 mv.visitAnnotation(DONTINLINE_SIG, true); 709 } 710 711 constantPlaceholder(lambdaForm); // keep LambdaForm instance & its compiled form lifetime tightly coupled. 712 713 if (lambdaForm.customized != null) { 714 // Since LambdaForm is customized for a particular MethodHandle, it's safe to substitute 715 // receiver MethodHandle (at slot #0) with an embedded constant and use it instead. 716 // It enables more efficient code generation in some situations, since embedded constants 717 // are compile-time constants for JIT compiler. 718 mv.visitLdcInsn(constantPlaceholder(lambdaForm.customized)); 719 mv.visitTypeInsn(Opcodes.CHECKCAST, MH); 720 assert(checkActualReceiver()); // expects MethodHandle on top of the stack 721 mv.visitVarInsn(Opcodes.ASTORE, localsMap[0]); 722 } 723 724 // iterate over the form's names, generating bytecode instructions for each 725 // start iterating at the first name following the arguments 726 Name onStack = null; 727 for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) { 728 Name name = lambdaForm.names[i]; 729 730 emitStoreResult(onStack); 731 onStack = name; // unless otherwise modified below 732 MethodHandleImpl.Intrinsic intr = name.function.intrinsicName(); 733 switch (intr) { 734 case SELECT_ALTERNATIVE: 735 assert lambdaForm.isSelectAlternative(i); 736 if (PROFILE_GWT) { 737 assert(name.arguments[0] instanceof Name && 738 ((Name)name.arguments[0]).refersTo(MethodHandleImpl.class, "profileBoolean")); 739 mv.visitAnnotation(INJECTEDPROFILE_SIG, true); 740 } 741 onStack = emitSelectAlternative(name, lambdaForm.names[i+1]); 742 i++; // skip MH.invokeBasic of the selectAlternative result 743 continue; 744 case GUARD_WITH_CATCH: 745 assert lambdaForm.isGuardWithCatch(i); 746 onStack = emitGuardWithCatch(i); 747 i += 2; // jump to the end of GWC idiom 748 continue; 749 case TRY_FINALLY: 750 assert lambdaForm.isTryFinally(i); 751 onStack = emitTryFinally(i); 752 i += 2; // jump to the end of the TF idiom 753 continue; 754 case LOOP: 755 assert lambdaForm.isLoop(i); 756 onStack = emitLoop(i); 757 i += 2; // jump to the end of the LOOP idiom 758 continue; 759 case NEW_ARRAY: 760 Class<?> rtype = name.function.methodType().returnType(); 761 if (isStaticallyNameable(rtype)) { 762 emitNewArray(name); 763 continue; 764 } 765 break; 766 case ARRAY_LOAD: 767 emitArrayLoad(name); 768 continue; 769 case ARRAY_STORE: 770 emitArrayStore(name); 771 continue; 772 case ARRAY_LENGTH: 773 emitArrayLength(name); 774 continue; 775 case IDENTITY: 776 assert(name.arguments.length == 1); 777 emitPushArguments(name, 0); 778 continue; 779 case ZERO: 780 assert(name.arguments.length == 0); 781 emitConst(name.type.basicTypeWrapper().zero()); 782 continue; 783 case NONE: 784 // no intrinsic associated 785 break; 786 default: 787 throw newInternalError("Unknown intrinsic: "+intr); 788 } 789 790 MemberName member = name.function.member(); 791 if (isStaticallyInvocable(member)) { 792 emitStaticInvoke(member, name); 793 } else { 794 emitInvoke(name); 795 } 796 } 797 798 // return statement 799 emitReturn(onStack); 800 801 methodEpilogue(); 802 } 803 804 /* 805 * @throws BytecodeGenerationException if something goes wrong when 806 * generating the byte code 807 */ 808 private byte[] toByteArray() { 809 try { 810 return cw.toByteArray(); 811 } catch (RuntimeException e) { 812 throw new BytecodeGenerationException(e); 813 } 814 } 815 816 @SuppressWarnings("serial") 817 static final class BytecodeGenerationException extends RuntimeException { 818 BytecodeGenerationException(Exception cause) { 819 super(cause); 820 } 821 } 822 823 void emitArrayLoad(Name name) { emitArrayOp(name, Opcodes.AALOAD); } 824 void emitArrayStore(Name name) { emitArrayOp(name, Opcodes.AASTORE); } 825 void emitArrayLength(Name name) { emitArrayOp(name, Opcodes.ARRAYLENGTH); } 826 827 void emitArrayOp(Name name, int arrayOpcode) { 828 assert arrayOpcode == Opcodes.AALOAD || arrayOpcode == Opcodes.AASTORE || arrayOpcode == Opcodes.ARRAYLENGTH; 829 Class<?> elementType = name.function.methodType().parameterType(0).getComponentType(); 830 assert elementType != null; 831 emitPushArguments(name, 0); 832 if (arrayOpcode != Opcodes.ARRAYLENGTH && elementType.isPrimitive()) { 833 Wrapper w = Wrapper.forPrimitiveType(elementType); 834 arrayOpcode = arrayInsnOpcode(arrayTypeCode(w), arrayOpcode); 835 } 836 mv.visitInsn(arrayOpcode); 837 } 838 839 /** 840 * Emit an invoke for the given name. 841 */ 842 void emitInvoke(Name name) { 843 assert(!name.isLinkerMethodInvoke()); // should use the static path for these 844 if (true) { 845 // push receiver 846 MethodHandle target = name.function.resolvedHandle(); 847 assert(target != null) : name.exprString(); 848 mv.visitLdcInsn(constantPlaceholder(target)); 849 emitReferenceCast(MethodHandle.class, target); 850 } else { 851 // load receiver 852 emitAloadInsn(0); 853 emitReferenceCast(MethodHandle.class, null); 854 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", LF_SIG); 855 mv.visitFieldInsn(Opcodes.GETFIELD, LF, "names", LFN_SIG); 856 // TODO more to come 857 } 858 859 // push arguments 860 emitPushArguments(name, 0); 861 862 // invocation 863 MethodType type = name.function.methodType(); 864 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false); 865 } 866 867 private static Class<?>[] STATICALLY_INVOCABLE_PACKAGES = { 868 // Sample classes from each package we are willing to bind to statically: 869 java.lang.Object.class, 870 java.util.Arrays.class, 871 jdk.internal.misc.Unsafe.class 872 //MethodHandle.class already covered 873 }; 874 875 static boolean isStaticallyInvocable(NamedFunction[] functions) { 876 for (NamedFunction nf : functions) { 877 if (!isStaticallyInvocable(nf.member())) { 878 return false; 879 } 880 } 881 return true; 882 } 883 884 static boolean isStaticallyInvocable(Name name) { 885 return isStaticallyInvocable(name.function.member()); 886 } 887 888 static boolean isStaticallyInvocable(MemberName member) { 889 if (member == null) return false; 890 if (member.isConstructor()) return false; 891 Class<?> cls = member.getDeclaringClass(); 892 if (cls.isArray() || cls.isPrimitive()) 893 return false; // FIXME 894 if (cls.isAnonymousClass() || cls.isLocalClass()) 895 return false; // inner class of some sort 896 if (cls.getClassLoader() != MethodHandle.class.getClassLoader()) 897 return false; // not on BCP 898 if (ReflectUtil.isVMAnonymousClass(cls)) // FIXME: switch to supported API once it is added 899 return false; 900 MethodType mtype = member.getMethodOrFieldType(); 901 if (!isStaticallyNameable(mtype.returnType())) 902 return false; 903 for (Class<?> ptype : mtype.parameterArray()) 904 if (!isStaticallyNameable(ptype)) 905 return false; 906 if (!member.isPrivate() && VerifyAccess.isSamePackage(MethodHandle.class, cls)) 907 return true; // in java.lang.invoke package 908 if (member.isPublic() && isStaticallyNameable(cls)) 909 return true; 910 return false; 911 } 912 913 static boolean isStaticallyNameable(Class<?> cls) { 914 if (cls == Object.class) 915 return true; 916 while (cls.isArray()) 917 cls = cls.getComponentType(); 918 if (cls.isPrimitive()) 919 return true; // int[].class, for example 920 if (ReflectUtil.isVMAnonymousClass(cls)) // FIXME: switch to supported API once it is added 921 return false; 922 // could use VerifyAccess.isClassAccessible but the following is a safe approximation 923 if (cls.getClassLoader() != Object.class.getClassLoader()) 924 return false; 925 if (VerifyAccess.isSamePackage(MethodHandle.class, cls)) 926 return true; 927 if (!Modifier.isPublic(cls.getModifiers())) 928 return false; 929 for (Class<?> pkgcls : STATICALLY_INVOCABLE_PACKAGES) { 930 if (VerifyAccess.isSamePackage(pkgcls, cls)) 931 return true; 932 } 933 return false; 934 } 935 936 void emitStaticInvoke(Name name) { 937 emitStaticInvoke(name.function.member(), name); 938 } 939 940 /** 941 * Emit an invoke for the given name, using the MemberName directly. 942 */ 943 void emitStaticInvoke(MemberName member, Name name) { 944 assert(member.equals(name.function.member())); 945 Class<?> defc = member.getDeclaringClass(); 946 String cname = getInternalName(defc); 947 String mname = member.getName(); 948 String mtype; 949 byte refKind = member.getReferenceKind(); 950 if (refKind == REF_invokeSpecial) { 951 // in order to pass the verifier, we need to convert this to invokevirtual in all cases 952 assert(member.canBeStaticallyBound()) : member; 953 refKind = REF_invokeVirtual; 954 } 955 956 assert(!(member.getDeclaringClass().isInterface() && refKind == REF_invokeVirtual)); 957 958 // push arguments 959 emitPushArguments(name, 0); 960 961 // invocation 962 if (member.isMethod()) { 963 mtype = member.getMethodType().toMethodDescriptorString(); 964 mv.visitMethodInsn(refKindOpcode(refKind), cname, mname, mtype, 965 member.getDeclaringClass().isInterface()); 966 } else { 967 mtype = MethodType.toFieldDescriptorString(member.getFieldType()); 968 mv.visitFieldInsn(refKindOpcode(refKind), cname, mname, mtype); 969 } 970 // Issue a type assertion for the result, so we can avoid casts later. 971 if (name.type == L_TYPE) { 972 Class<?> rtype = member.getInvocationType().returnType(); 973 assert(!rtype.isPrimitive()); 974 if (rtype != Object.class && !rtype.isInterface()) { 975 assertStaticType(rtype, name); 976 } 977 } 978 } 979 980 void emitNewArray(Name name) throws InternalError { 981 Class<?> rtype = name.function.methodType().returnType(); 982 if (name.arguments.length == 0) { 983 // The array will be a constant. 984 Object emptyArray; 985 try { 986 emptyArray = name.function.resolvedHandle().invoke(); 987 } catch (Throwable ex) { 988 throw newInternalError(ex); 989 } 990 assert(java.lang.reflect.Array.getLength(emptyArray) == 0); 991 assert(emptyArray.getClass() == rtype); // exact typing 992 mv.visitLdcInsn(constantPlaceholder(emptyArray)); 993 emitReferenceCast(rtype, emptyArray); 994 return; 995 } 996 Class<?> arrayElementType = rtype.getComponentType(); 997 assert(arrayElementType != null); 998 emitIconstInsn(name.arguments.length); 999 int xas = Opcodes.AASTORE; 1000 if (!arrayElementType.isPrimitive()) { 1001 mv.visitTypeInsn(Opcodes.ANEWARRAY, getInternalName(arrayElementType)); 1002 } else { 1003 byte tc = arrayTypeCode(Wrapper.forPrimitiveType(arrayElementType)); 1004 xas = arrayInsnOpcode(tc, xas); 1005 mv.visitIntInsn(Opcodes.NEWARRAY, tc); 1006 } 1007 // store arguments 1008 for (int i = 0; i < name.arguments.length; i++) { 1009 mv.visitInsn(Opcodes.DUP); 1010 emitIconstInsn(i); 1011 emitPushArgument(name, i); 1012 mv.visitInsn(xas); 1013 } 1014 // the array is left on the stack 1015 assertStaticType(rtype, name); 1016 } 1017 int refKindOpcode(byte refKind) { 1018 switch (refKind) { 1019 case REF_invokeVirtual: return Opcodes.INVOKEVIRTUAL; 1020 case REF_invokeStatic: return Opcodes.INVOKESTATIC; 1021 case REF_invokeSpecial: return Opcodes.INVOKESPECIAL; 1022 case REF_invokeInterface: return Opcodes.INVOKEINTERFACE; 1023 case REF_getField: return Opcodes.GETFIELD; 1024 case REF_putField: return Opcodes.PUTFIELD; 1025 case REF_getStatic: return Opcodes.GETSTATIC; 1026 case REF_putStatic: return Opcodes.PUTSTATIC; 1027 } 1028 throw new InternalError("refKind="+refKind); 1029 } 1030 1031 /** 1032 * Emit bytecode for the selectAlternative idiom. 1033 * 1034 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithTest): 1035 * <blockquote><pre>{@code 1036 * Lambda(a0:L,a1:I)=>{ 1037 * t2:I=foo.test(a1:I); 1038 * t3:L=MethodHandleImpl.selectAlternative(t2:I,(MethodHandle(int)int),(MethodHandle(int)int)); 1039 * t4:I=MethodHandle.invokeBasic(t3:L,a1:I);t4:I} 1040 * }</pre></blockquote> 1041 */ 1042 private Name emitSelectAlternative(Name selectAlternativeName, Name invokeBasicName) { 1043 assert isStaticallyInvocable(invokeBasicName); 1044 1045 Name receiver = (Name) invokeBasicName.arguments[0]; 1046 1047 Label L_fallback = new Label(); 1048 Label L_done = new Label(); 1049 1050 // load test result 1051 emitPushArgument(selectAlternativeName, 0); 1052 1053 // if_icmpne L_fallback 1054 mv.visitJumpInsn(Opcodes.IFEQ, L_fallback); 1055 1056 // invoke selectAlternativeName.arguments[1] 1057 Class<?>[] preForkClasses = localClasses.clone(); 1058 emitPushArgument(selectAlternativeName, 1); // get 2nd argument of selectAlternative 1059 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot 1060 emitStaticInvoke(invokeBasicName); 1061 1062 // goto L_done 1063 mv.visitJumpInsn(Opcodes.GOTO, L_done); 1064 1065 // L_fallback: 1066 mv.visitLabel(L_fallback); 1067 1068 // invoke selectAlternativeName.arguments[2] 1069 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length); 1070 emitPushArgument(selectAlternativeName, 2); // get 3rd argument of selectAlternative 1071 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot 1072 emitStaticInvoke(invokeBasicName); 1073 1074 // L_done: 1075 mv.visitLabel(L_done); 1076 // for now do not bother to merge typestate; just reset to the dominator state 1077 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length); 1078 1079 return invokeBasicName; // return what's on stack 1080 } 1081 1082 /** 1083 * Emit bytecode for the guardWithCatch idiom. 1084 * 1085 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithCatch): 1086 * <blockquote><pre>{@code 1087 * guardWithCatch=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{ 1088 * t8:L=MethodHandle.invokeBasic(a4:L,a6:L,a7:L); 1089 * t9:L=MethodHandleImpl.guardWithCatch(a1:L,a2:L,a3:L,t8:L); 1090 * t10:I=MethodHandle.invokeBasic(a5:L,t9:L);t10:I} 1091 * }</pre></blockquote> 1092 * 1093 * It is compiled into bytecode equivalent of the following code: 1094 * <blockquote><pre>{@code 1095 * try { 1096 * return a1.invokeBasic(a6, a7); 1097 * } catch (Throwable e) { 1098 * if (!a2.isInstance(e)) throw e; 1099 * return a3.invokeBasic(ex, a6, a7); 1100 * }} 1101 */ 1102 private Name emitGuardWithCatch(int pos) { 1103 Name args = lambdaForm.names[pos]; 1104 Name invoker = lambdaForm.names[pos+1]; 1105 Name result = lambdaForm.names[pos+2]; 1106 1107 Label L_startBlock = new Label(); 1108 Label L_endBlock = new Label(); 1109 Label L_handler = new Label(); 1110 Label L_done = new Label(); 1111 1112 Class<?> returnType = result.function.resolvedHandle().type().returnType(); 1113 MethodType type = args.function.resolvedHandle().type() 1114 .dropParameterTypes(0,1) 1115 .changeReturnType(returnType); 1116 1117 mv.visitTryCatchBlock(L_startBlock, L_endBlock, L_handler, "java/lang/Throwable"); 1118 1119 // Normal case 1120 mv.visitLabel(L_startBlock); 1121 // load target 1122 emitPushArgument(invoker, 0); 1123 emitPushArguments(args, 1); // skip 1st argument: method handle 1124 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false); 1125 mv.visitLabel(L_endBlock); 1126 mv.visitJumpInsn(Opcodes.GOTO, L_done); 1127 1128 // Exceptional case 1129 mv.visitLabel(L_handler); 1130 1131 // Check exception's type 1132 mv.visitInsn(Opcodes.DUP); 1133 // load exception class 1134 emitPushArgument(invoker, 1); 1135 mv.visitInsn(Opcodes.SWAP); 1136 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Class", "isInstance", "(Ljava/lang/Object;)Z", false); 1137 Label L_rethrow = new Label(); 1138 mv.visitJumpInsn(Opcodes.IFEQ, L_rethrow); 1139 1140 // Invoke catcher 1141 // load catcher 1142 emitPushArgument(invoker, 2); 1143 mv.visitInsn(Opcodes.SWAP); 1144 emitPushArguments(args, 1); // skip 1st argument: method handle 1145 MethodType catcherType = type.insertParameterTypes(0, Throwable.class); 1146 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", catcherType.basicType().toMethodDescriptorString(), false); 1147 mv.visitJumpInsn(Opcodes.GOTO, L_done); 1148 1149 mv.visitLabel(L_rethrow); 1150 mv.visitInsn(Opcodes.ATHROW); 1151 1152 mv.visitLabel(L_done); 1153 1154 return result; 1155 } 1156 1157 /** 1158 * Emit bytecode for the tryFinally idiom. 1159 * <p> 1160 * The pattern looks like (Cf. MethodHandleImpl.makeTryFinally): 1161 * <blockquote><pre>{@code 1162 * // a0: BMH 1163 * // a1: target, a2: cleanup 1164 * // a3: box, a4: unbox 1165 * // a5 (and following): arguments 1166 * tryFinally=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L)=>{ 1167 * t6:L=MethodHandle.invokeBasic(a3:L,a5:L); // box the arguments into an Object[] 1168 * t7:L=MethodHandleImpl.tryFinally(a1:L,a2:L,t6:L); // call the tryFinally executor 1169 * t8:L=MethodHandle.invokeBasic(a4:L,t7:L);t8:L} // unbox the result; return the result 1170 * }</pre></blockquote> 1171 * <p> 1172 * It is compiled into bytecode equivalent to the following code: 1173 * <blockquote><pre>{@code 1174 * Throwable t; 1175 * Object r; 1176 * try { 1177 * r = a1.invokeBasic(a5); 1178 * } catch (Throwable thrown) { 1179 * t = thrown; 1180 * throw t; 1181 * } finally { 1182 * r = a2.invokeBasic(t, r, a5); 1183 * } 1184 * return r; 1185 * }</pre></blockquote> 1186 * <p> 1187 * Specifically, the bytecode will have the following form (the stack effects are given for the beginnings of 1188 * blocks, and for the situations after executing the given instruction - the code will have a slightly different 1189 * shape if the return type is {@code void}): 1190 * <blockquote><pre>{@code 1191 * TRY: (--) 1192 * load target (-- target) 1193 * load args (-- args... target) 1194 * INVOKEVIRTUAL MethodHandle.invokeBasic (depends) 1195 * FINALLY_NORMAL: (-- r) 1196 * load cleanup (-- cleanup r) 1197 * SWAP (-- r cleanup) 1198 * ACONST_NULL (-- t r cleanup) 1199 * SWAP (-- r t cleanup) 1200 * load args (-- args... r t cleanup) 1201 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r) 1202 * GOTO DONE 1203 * CATCH: (-- t) 1204 * DUP (-- t t) 1205 * FINALLY_EXCEPTIONAL: (-- t t) 1206 * load cleanup (-- cleanup t t) 1207 * SWAP (-- t cleanup t) 1208 * load default for r (-- r t cleanup t) 1209 * load args (-- args... r t cleanup t) 1210 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r t) 1211 * POP (-- t) 1212 * ATHROW 1213 * DONE: (-- r) 1214 * }</pre></blockquote> 1215 */ 1216 private Name emitTryFinally(int pos) { 1217 Name args = lambdaForm.names[pos]; 1218 Name invoker = lambdaForm.names[pos+1]; 1219 Name result = lambdaForm.names[pos+2]; 1220 1221 Label lFrom = new Label(); 1222 Label lTo = new Label(); 1223 Label lCatch = new Label(); 1224 Label lDone = new Label(); 1225 1226 Class<?> returnType = result.function.resolvedHandle().type().returnType(); 1227 boolean isNonVoid = returnType != void.class; 1228 MethodType type = args.function.resolvedHandle().type() 1229 .dropParameterTypes(0,1) 1230 .changeReturnType(returnType); 1231 MethodType cleanupType = type.insertParameterTypes(0, Throwable.class); 1232 if (isNonVoid) { 1233 cleanupType = cleanupType.insertParameterTypes(1, returnType); 1234 } 1235 String cleanupDesc = cleanupType.basicType().toMethodDescriptorString(); 1236 1237 // exception handler table 1238 mv.visitTryCatchBlock(lFrom, lTo, lCatch, "java/lang/Throwable"); 1239 1240 // TRY: 1241 mv.visitLabel(lFrom); 1242 emitPushArgument(invoker, 0); // load target 1243 emitPushArguments(args, 1); // load args (skip 0: method handle) 1244 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false); 1245 mv.visitLabel(lTo); 1246 1247 // FINALLY_NORMAL: 1248 emitPushArgument(invoker, 1); // load cleanup 1249 if (isNonVoid) { 1250 mv.visitInsn(Opcodes.SWAP); 1251 } 1252 mv.visitInsn(Opcodes.ACONST_NULL); 1253 if (isNonVoid) { 1254 mv.visitInsn(Opcodes.SWAP); 1255 } 1256 emitPushArguments(args, 1); // load args (skip 0: method handle) 1257 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", cleanupDesc, false); 1258 mv.visitJumpInsn(Opcodes.GOTO, lDone); 1259 1260 // CATCH: 1261 mv.visitLabel(lCatch); 1262 mv.visitInsn(Opcodes.DUP); 1263 1264 // FINALLY_EXCEPTIONAL: 1265 emitPushArgument(invoker, 1); // load cleanup 1266 mv.visitInsn(Opcodes.SWAP); 1267 if (isNonVoid) { 1268 emitZero(BasicType.basicType(returnType)); // load default for result 1269 } 1270 emitPushArguments(args, 1); // load args (skip 0: method handle) 1271 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", cleanupDesc, false); 1272 if (isNonVoid) { 1273 mv.visitInsn(Opcodes.POP); 1274 } 1275 mv.visitInsn(Opcodes.ATHROW); 1276 1277 // DONE: 1278 mv.visitLabel(lDone); 1279 1280 return result; 1281 } 1282 1283 /** 1284 * Emit bytecode for the loop idiom. 1285 * <p> 1286 * The pattern looks like (Cf. MethodHandleImpl.loop): 1287 * <blockquote><pre>{@code 1288 * // a0: BMH 1289 * // a1: inits, a2: steps, a3: preds, a4: finis 1290 * // a5: box, a6: unbox 1291 * // a7 (and following): arguments 1292 * loop=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{ 1293 * t8:L=MethodHandle.invokeBasic(a5:L,a7:L); // box the arguments into an Object[] 1294 * t9:L=MethodHandleImpl.loop(bt:L,a1:L,a2:L,a3:L,a4:L,t8:L); // call the loop executor (with supplied types in bt) 1295 * t10:L=MethodHandle.invokeBasic(a6:L,t9:L);t10:L} // unbox the result; return the result 1296 * }</pre></blockquote> 1297 * <p> 1298 * It is compiled into bytecode equivalent to the code seen in {@link MethodHandleImpl#loop(BasicType[], 1299 * MethodHandle[], MethodHandle[], MethodHandle[], MethodHandle[], Object...)}, with the difference that no arrays 1300 * will be used for local state storage. Instead, the local state will be mapped to actual stack slots. 1301 * <p> 1302 * Bytecode generation applies an unrolling scheme to enable better bytecode generation regarding local state type 1303 * handling. The generated bytecode will have the following form ({@code void} types are ignored for convenience). 1304 * Assume there are {@code C} clauses in the loop. 1305 * <blockquote><pre>{@code 1306 * INIT: (INIT_SEQ for clause 1) 1307 * ... 1308 * (INIT_SEQ for clause C) 1309 * LOOP: (LOOP_SEQ for clause 1) 1310 * ... 1311 * (LOOP_SEQ for clause C) 1312 * GOTO LOOP 1313 * DONE: ... 1314 * }</pre></blockquote> 1315 * <p> 1316 * The {@code INIT_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has 1317 * the following shape. Assume slot {@code vx} is used to hold the state for clause {@code x}. 1318 * <blockquote><pre>{@code 1319 * INIT_SEQ_x: ALOAD inits 1320 * CHECKCAST MethodHandle[] 1321 * ICONST x 1322 * AALOAD // load the init handle for clause x 1323 * load args 1324 * INVOKEVIRTUAL MethodHandle.invokeBasic 1325 * store vx 1326 * }</pre></blockquote> 1327 * <p> 1328 * The {@code LOOP_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has 1329 * the following shape. Again, assume slot {@code vx} is used to hold the state for clause {@code x}. 1330 * <blockquote><pre>{@code 1331 * LOOP_SEQ_x: ALOAD steps 1332 * CHECKCAST MethodHandle[] 1333 * ICONST x 1334 * AALOAD // load the step handle for clause x 1335 * load locals 1336 * load args 1337 * INVOKEVIRTUAL MethodHandle.invokeBasic 1338 * store vx 1339 * ALOAD preds 1340 * CHECKCAST MethodHandle[] 1341 * ICONST x 1342 * AALOAD // load the pred handle for clause x 1343 * load locals 1344 * load args 1345 * INVOKEVIRTUAL MethodHandle.invokeBasic 1346 * IFNE LOOP_SEQ_x+1 // predicate returned false -> jump to next clause 1347 * ALOAD finis 1348 * CHECKCAST MethodHandle[] 1349 * ICONST x 1350 * AALOAD // load the fini handle for clause x 1351 * load locals 1352 * load args 1353 * INVOKEVIRTUAL MethodHandle.invokeBasic 1354 * GOTO DONE // jump beyond end of clauses to return from loop 1355 * }</pre></blockquote> 1356 */ 1357 private Name emitLoop(int pos) { 1358 Name args = lambdaForm.names[pos]; 1359 Name invoker = lambdaForm.names[pos+1]; 1360 Name result = lambdaForm.names[pos+2]; 1361 1362 // extract clause and loop-local state types 1363 // find the type info in the loop invocation 1364 BasicType[] loopClauseTypes = (BasicType[]) invoker.arguments[0]; 1365 Class<?>[] loopLocalStateTypes = Stream.of(loopClauseTypes). 1366 filter(bt -> bt != BasicType.V_TYPE).map(BasicType::basicTypeClass).toArray(Class<?>[]::new); 1367 1368 final int firstLoopStateIndex = extendLocalsMap(loopLocalStateTypes); 1369 1370 Class<?> returnType = result.function.resolvedHandle().type().returnType(); 1371 MethodType loopType = args.function.resolvedHandle().type() 1372 .dropParameterTypes(0,1) 1373 .changeReturnType(returnType); 1374 MethodType loopHandleType = loopType.insertParameterTypes(0, loopLocalStateTypes); 1375 MethodType predType = loopHandleType.changeReturnType(boolean.class); 1376 MethodType finiType = loopHandleType; 1377 1378 final int nClauses = loopClauseTypes.length; 1379 1380 // indices to invoker arguments to load method handle arrays 1381 final int inits = 1; 1382 final int steps = 2; 1383 final int preds = 3; 1384 final int finis = 4; 1385 1386 Label lLoop = new Label(); 1387 Label lDone = new Label(); 1388 Label lNext; 1389 1390 // INIT: 1391 for (int c = 0, state = 0; c < nClauses; ++c) { 1392 MethodType cInitType = loopType.changeReturnType(loopClauseTypes[c].basicTypeClass()); 1393 emitLoopHandleInvoke(invoker, inits, c, args, false, cInitType, loopLocalStateTypes, firstLoopStateIndex); 1394 if (cInitType.returnType() != void.class) { 1395 emitStoreInsn(BasicType.basicType(cInitType.returnType()), firstLoopStateIndex + state); 1396 ++state; 1397 } 1398 } 1399 1400 // LOOP: 1401 mv.visitLabel(lLoop); 1402 1403 for (int c = 0, state = 0; c < nClauses; ++c) { 1404 lNext = new Label(); 1405 1406 MethodType stepType = loopHandleType.changeReturnType(loopClauseTypes[c].basicTypeClass()); 1407 boolean isVoid = stepType.returnType() == void.class; 1408 1409 // invoke loop step 1410 emitLoopHandleInvoke(invoker, steps, c, args, true, stepType, loopLocalStateTypes, firstLoopStateIndex); 1411 if (!isVoid) { 1412 emitStoreInsn(BasicType.basicType(stepType.returnType()), firstLoopStateIndex + state); 1413 ++state; 1414 } 1415 1416 // invoke loop predicate 1417 emitLoopHandleInvoke(invoker, preds, c, args, true, predType, loopLocalStateTypes, firstLoopStateIndex); 1418 mv.visitJumpInsn(Opcodes.IFNE, lNext); 1419 1420 // invoke fini 1421 emitLoopHandleInvoke(invoker, finis, c, args, true, finiType, loopLocalStateTypes, firstLoopStateIndex); 1422 mv.visitJumpInsn(Opcodes.GOTO, lDone); 1423 1424 // this is the beginning of the next loop clause 1425 mv.visitLabel(lNext); 1426 } 1427 1428 mv.visitJumpInsn(Opcodes.GOTO, lLoop); 1429 1430 // DONE: 1431 mv.visitLabel(lDone); 1432 1433 return result; 1434 } 1435 1436 private int extendLocalsMap(Class<?>[] types) { 1437 int firstSlot = localsMap.length - 1; 1438 localsMap = Arrays.copyOf(localsMap, localsMap.length + types.length); 1439 localClasses = Arrays.copyOf(localClasses, localClasses.length + types.length); 1440 System.arraycopy(types, 0, localClasses, firstSlot, types.length); 1441 int index = localsMap[firstSlot - 1] + 1; 1442 int lastSlots = 0; 1443 for (int i = 0; i < types.length; ++i) { 1444 localsMap[firstSlot + i] = index; 1445 lastSlots = BasicType.basicType(localClasses[firstSlot + i]).basicTypeSlots(); 1446 index += lastSlots; 1447 } 1448 localsMap[localsMap.length - 1] = index - lastSlots; 1449 return firstSlot; 1450 } 1451 1452 private void emitLoopHandleInvoke(Name holder, int handles, int clause, Name args, boolean pushLocalState, 1453 MethodType type, Class<?>[] loopLocalStateTypes, int firstLoopStateSlot) { 1454 // load handle for clause 1455 emitPushArgument(holder, handles); 1456 emitIconstInsn(clause); 1457 mv.visitInsn(Opcodes.AALOAD); 1458 // load loop state (preceding the other arguments) 1459 if (pushLocalState) { 1460 for (int s = 0; s < loopLocalStateTypes.length; ++s) { 1461 emitLoadInsn(BasicType.basicType(loopLocalStateTypes[s]), firstLoopStateSlot + s); 1462 } 1463 } 1464 // load loop args (skip 0: method handle) 1465 emitPushArguments(args, 1); 1466 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.toMethodDescriptorString(), false); 1467 } 1468 1469 private void emitZero(BasicType type) { 1470 switch (type) { 1471 case I_TYPE: mv.visitInsn(Opcodes.ICONST_0); break; 1472 case J_TYPE: mv.visitInsn(Opcodes.LCONST_0); break; 1473 case F_TYPE: mv.visitInsn(Opcodes.FCONST_0); break; 1474 case D_TYPE: mv.visitInsn(Opcodes.DCONST_0); break; 1475 case L_TYPE: mv.visitInsn(Opcodes.ACONST_NULL); break; 1476 default: throw new InternalError("unknown type: " + type); 1477 } 1478 } 1479 1480 private void emitPushArguments(Name args, int start) { 1481 MethodType type = args.function.methodType(); 1482 for (int i = start; i < args.arguments.length; i++) { 1483 emitPushArgument(type.parameterType(i), args.arguments[i]); 1484 } 1485 } 1486 1487 private void emitPushArgument(Name name, int paramIndex) { 1488 Object arg = name.arguments[paramIndex]; 1489 Class<?> ptype = name.function.methodType().parameterType(paramIndex); 1490 emitPushArgument(ptype, arg); 1491 } 1492 1493 private void emitPushArgument(Class<?> ptype, Object arg) { 1494 BasicType bptype = basicType(ptype); 1495 if (arg instanceof Name) { 1496 Name n = (Name) arg; 1497 emitLoadInsn(n.type, n.index()); 1498 emitImplicitConversion(n.type, ptype, n); 1499 } else if ((arg == null || arg instanceof String) && bptype == L_TYPE) { 1500 emitConst(arg); 1501 } else { 1502 if (Wrapper.isWrapperType(arg.getClass()) && bptype != L_TYPE) { 1503 emitConst(arg); 1504 } else { 1505 mv.visitLdcInsn(constantPlaceholder(arg)); 1506 emitImplicitConversion(L_TYPE, ptype, arg); 1507 } 1508 } 1509 } 1510 1511 /** 1512 * Store the name to its local, if necessary. 1513 */ 1514 private void emitStoreResult(Name name) { 1515 if (name != null && name.type != V_TYPE) { 1516 // non-void: actually assign 1517 emitStoreInsn(name.type, name.index()); 1518 } 1519 } 1520 1521 /** 1522 * Emits a return statement from a LF invoker. If required, the result type is cast to the correct return type. 1523 */ 1524 private void emitReturn(Name onStack) { 1525 // return statement 1526 Class<?> rclass = invokerType.returnType(); 1527 BasicType rtype = lambdaForm.returnType(); 1528 assert(rtype == basicType(rclass)); // must agree 1529 if (rtype == V_TYPE) { 1530 // void 1531 mv.visitInsn(Opcodes.RETURN); 1532 // it doesn't matter what rclass is; the JVM will discard any value 1533 } else { 1534 LambdaForm.Name rn = lambdaForm.names[lambdaForm.result]; 1535 1536 // put return value on the stack if it is not already there 1537 if (rn != onStack) { 1538 emitLoadInsn(rtype, lambdaForm.result); 1539 } 1540 1541 emitImplicitConversion(rtype, rclass, rn); 1542 1543 // generate actual return statement 1544 emitReturnInsn(rtype); 1545 } 1546 } 1547 1548 /** 1549 * Emit a type conversion bytecode casting from "from" to "to". 1550 */ 1551 private void emitPrimCast(Wrapper from, Wrapper to) { 1552 // Here's how. 1553 // - indicates forbidden 1554 // <-> indicates implicit 1555 // to ----> boolean byte short char int long float double 1556 // from boolean <-> - - - - - - - 1557 // byte - <-> i2s i2c <-> i2l i2f i2d 1558 // short - i2b <-> i2c <-> i2l i2f i2d 1559 // char - i2b i2s <-> <-> i2l i2f i2d 1560 // int - i2b i2s i2c <-> i2l i2f i2d 1561 // long - l2i,i2b l2i,i2s l2i,i2c l2i <-> l2f l2d 1562 // float - f2i,i2b f2i,i2s f2i,i2c f2i f2l <-> f2d 1563 // double - d2i,i2b d2i,i2s d2i,i2c d2i d2l d2f <-> 1564 if (from == to) { 1565 // no cast required, should be dead code anyway 1566 return; 1567 } 1568 if (from.isSubwordOrInt()) { 1569 // cast from {byte,short,char,int} to anything 1570 emitI2X(to); 1571 } else { 1572 // cast from {long,float,double} to anything 1573 if (to.isSubwordOrInt()) { 1574 // cast to {byte,short,char,int} 1575 emitX2I(from); 1576 if (to.bitWidth() < 32) { 1577 // targets other than int require another conversion 1578 emitI2X(to); 1579 } 1580 } else { 1581 // cast to {long,float,double} - this is verbose 1582 boolean error = false; 1583 switch (from) { 1584 case LONG: 1585 switch (to) { 1586 case FLOAT: mv.visitInsn(Opcodes.L2F); break; 1587 case DOUBLE: mv.visitInsn(Opcodes.L2D); break; 1588 default: error = true; break; 1589 } 1590 break; 1591 case FLOAT: 1592 switch (to) { 1593 case LONG : mv.visitInsn(Opcodes.F2L); break; 1594 case DOUBLE: mv.visitInsn(Opcodes.F2D); break; 1595 default: error = true; break; 1596 } 1597 break; 1598 case DOUBLE: 1599 switch (to) { 1600 case LONG : mv.visitInsn(Opcodes.D2L); break; 1601 case FLOAT: mv.visitInsn(Opcodes.D2F); break; 1602 default: error = true; break; 1603 } 1604 break; 1605 default: 1606 error = true; 1607 break; 1608 } 1609 if (error) { 1610 throw new IllegalStateException("unhandled prim cast: " + from + "2" + to); 1611 } 1612 } 1613 } 1614 } 1615 1616 private void emitI2X(Wrapper type) { 1617 switch (type) { 1618 case BYTE: mv.visitInsn(Opcodes.I2B); break; 1619 case SHORT: mv.visitInsn(Opcodes.I2S); break; 1620 case CHAR: mv.visitInsn(Opcodes.I2C); break; 1621 case INT: /* naught */ break; 1622 case LONG: mv.visitInsn(Opcodes.I2L); break; 1623 case FLOAT: mv.visitInsn(Opcodes.I2F); break; 1624 case DOUBLE: mv.visitInsn(Opcodes.I2D); break; 1625 case BOOLEAN: 1626 // For compatibility with ValueConversions and explicitCastArguments: 1627 mv.visitInsn(Opcodes.ICONST_1); 1628 mv.visitInsn(Opcodes.IAND); 1629 break; 1630 default: throw new InternalError("unknown type: " + type); 1631 } 1632 } 1633 1634 private void emitX2I(Wrapper type) { 1635 switch (type) { 1636 case LONG: mv.visitInsn(Opcodes.L2I); break; 1637 case FLOAT: mv.visitInsn(Opcodes.F2I); break; 1638 case DOUBLE: mv.visitInsn(Opcodes.D2I); break; 1639 default: throw new InternalError("unknown type: " + type); 1640 } 1641 } 1642 1643 /** 1644 * Generate bytecode for a LambdaForm.vmentry which calls interpretWithArguments. 1645 */ 1646 static MemberName generateLambdaFormInterpreterEntryPoint(MethodType mt) { 1647 assert(isValidSignature(basicTypeSignature(mt))); 1648 String name = "interpret_"+basicTypeChar(mt.returnType()); 1649 MethodType type = mt; // includes leading argument 1650 type = type.changeParameterType(0, MethodHandle.class); 1651 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("LFI", name, type); 1652 return g.loadMethod(g.generateLambdaFormInterpreterEntryPointBytes()); 1653 } 1654 1655 private byte[] generateLambdaFormInterpreterEntryPointBytes() { 1656 classFilePrologue(); 1657 methodPrologue(); 1658 1659 // Suppress this method in backtraces displayed to the user. 1660 mv.visitAnnotation(LF_HIDDEN_SIG, true); 1661 1662 // Don't inline the interpreter entry. 1663 mv.visitAnnotation(DONTINLINE_SIG, true); 1664 1665 // create parameter array 1666 emitIconstInsn(invokerType.parameterCount()); 1667 mv.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object"); 1668 1669 // fill parameter array 1670 for (int i = 0; i < invokerType.parameterCount(); i++) { 1671 Class<?> ptype = invokerType.parameterType(i); 1672 mv.visitInsn(Opcodes.DUP); 1673 emitIconstInsn(i); 1674 emitLoadInsn(basicType(ptype), i); 1675 // box if primitive type 1676 if (ptype.isPrimitive()) { 1677 emitBoxing(Wrapper.forPrimitiveType(ptype)); 1678 } 1679 mv.visitInsn(Opcodes.AASTORE); 1680 } 1681 // invoke 1682 emitAloadInsn(0); 1683 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", "Ljava/lang/invoke/LambdaForm;"); 1684 mv.visitInsn(Opcodes.SWAP); // swap form and array; avoid local variable 1685 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, LF, "interpretWithArguments", "([Ljava/lang/Object;)Ljava/lang/Object;", false); 1686 1687 // maybe unbox 1688 Class<?> rtype = invokerType.returnType(); 1689 if (rtype.isPrimitive() && rtype != void.class) { 1690 emitUnboxing(Wrapper.forPrimitiveType(rtype)); 1691 } 1692 1693 // return statement 1694 emitReturnInsn(basicType(rtype)); 1695 1696 methodEpilogue(); 1697 bogusMethod(invokerType); 1698 1699 final byte[] classFile = cw.toByteArray(); 1700 maybeDump(className, classFile); 1701 return classFile; 1702 } 1703 1704 /** 1705 * Generate bytecode for a NamedFunction invoker. 1706 */ 1707 static MemberName generateNamedFunctionInvoker(MethodTypeForm typeForm) { 1708 MethodType invokerType = NamedFunction.INVOKER_METHOD_TYPE; 1709 String invokerName = "invoke_" + shortenSignature(basicTypeSignature(typeForm.erasedType())); 1710 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("NFI", invokerName, invokerType); 1711 return g.loadMethod(g.generateNamedFunctionInvokerImpl(typeForm)); 1712 } 1713 1714 private byte[] generateNamedFunctionInvokerImpl(MethodTypeForm typeForm) { 1715 MethodType dstType = typeForm.erasedType(); 1716 classFilePrologue(); 1717 methodPrologue(); 1718 1719 // Suppress this method in backtraces displayed to the user. 1720 mv.visitAnnotation(LF_HIDDEN_SIG, true); 1721 1722 // Force inlining of this invoker method. 1723 mv.visitAnnotation(FORCEINLINE_SIG, true); 1724 1725 // Load receiver 1726 emitAloadInsn(0); 1727 1728 // Load arguments from array 1729 for (int i = 0; i < dstType.parameterCount(); i++) { 1730 emitAloadInsn(1); 1731 emitIconstInsn(i); 1732 mv.visitInsn(Opcodes.AALOAD); 1733 1734 // Maybe unbox 1735 Class<?> dptype = dstType.parameterType(i); 1736 if (dptype.isPrimitive()) { 1737 Wrapper dstWrapper = Wrapper.forBasicType(dptype); 1738 Wrapper srcWrapper = dstWrapper.isSubwordOrInt() ? Wrapper.INT : dstWrapper; // narrow subword from int 1739 emitUnboxing(srcWrapper); 1740 emitPrimCast(srcWrapper, dstWrapper); 1741 } 1742 } 1743 1744 // Invoke 1745 String targetDesc = dstType.basicType().toMethodDescriptorString(); 1746 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", targetDesc, false); 1747 1748 // Box primitive types 1749 Class<?> rtype = dstType.returnType(); 1750 if (rtype != void.class && rtype.isPrimitive()) { 1751 Wrapper srcWrapper = Wrapper.forBasicType(rtype); 1752 Wrapper dstWrapper = srcWrapper.isSubwordOrInt() ? Wrapper.INT : srcWrapper; // widen subword to int 1753 // boolean casts not allowed 1754 emitPrimCast(srcWrapper, dstWrapper); 1755 emitBoxing(dstWrapper); 1756 } 1757 1758 // If the return type is void we return a null reference. 1759 if (rtype == void.class) { 1760 mv.visitInsn(Opcodes.ACONST_NULL); 1761 } 1762 emitReturnInsn(L_TYPE); // NOTE: NamedFunction invokers always return a reference value. 1763 1764 methodEpilogue(); 1765 bogusMethod(dstType); 1766 1767 final byte[] classFile = cw.toByteArray(); 1768 maybeDump(className, classFile); 1769 return classFile; 1770 } 1771 1772 /** 1773 * Emit a bogus method that just loads some string constants. This is to get the constants into the constant pool 1774 * for debugging purposes. 1775 */ 1776 private void bogusMethod(Object... os) { 1777 if (DUMP_CLASS_FILES) { 1778 mv = cw.visitMethod(Opcodes.ACC_STATIC, "dummy", "()V", null, null); 1779 for (Object o : os) { 1780 mv.visitLdcInsn(o.toString()); 1781 mv.visitInsn(Opcodes.POP); 1782 } 1783 mv.visitInsn(Opcodes.RETURN); 1784 mv.visitMaxs(0, 0); 1785 mv.visitEnd(); 1786 } 1787 } 1788 }