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