1 /* 2 * Copyright (c) 2012, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.lang.invoke; 27 28 import jdk.internal.org.objectweb.asm.ClassWriter; 29 import jdk.internal.org.objectweb.asm.Label; 30 import jdk.internal.org.objectweb.asm.MethodVisitor; 31 import jdk.internal.org.objectweb.asm.Opcodes; 32 import jdk.internal.org.objectweb.asm.Type; 33 import sun.invoke.util.VerifyAccess; 34 import sun.invoke.util.VerifyType; 35 import sun.invoke.util.Wrapper; 36 import sun.reflect.misc.ReflectUtil; 37 38 import java.io.File; 39 import java.io.FileOutputStream; 40 import java.io.IOException; 41 import java.lang.reflect.Modifier; 42 import java.util.ArrayList; 43 import java.util.Arrays; 44 import java.util.HashMap; 45 import java.util.stream.Stream; 46 47 import static java.lang.invoke.LambdaForm.BasicType; 48 import static java.lang.invoke.LambdaForm.BasicType.*; 49 import static java.lang.invoke.LambdaForm.*; 50 import static java.lang.invoke.MethodHandleNatives.Constants.*; 51 import static java.lang.invoke.MethodHandleStatics.*; 52 53 /** 54 * Code generation backend for LambdaForm. 55 * <p> 56 * @author John Rose, JSR 292 EG 57 */ 58 class InvokerBytecodeGenerator { 59 /** Define class names for convenience. */ 60 private static final String MH = "java/lang/invoke/MethodHandle"; 61 private static final String MHI = "java/lang/invoke/MethodHandleImpl"; 62 private static final String LF = "java/lang/invoke/LambdaForm"; 63 private static final String LFN = "java/lang/invoke/LambdaForm$Name"; 64 private static final String CLS = "java/lang/Class"; 65 private static final String OBJ = "java/lang/Object"; 66 private static final String OBJARY = "[Ljava/lang/Object;"; 67 68 private static final String LOOP_CLAUSES = MHI + "$LoopClauses"; 69 private static final String MHARY2 = "[[L" + MH + ";"; 70 71 private static final String LF_SIG = "L" + LF + ";"; 72 private static final String LFN_SIG = "L" + LFN + ";"; 73 private static final String LL_SIG = "(L" + OBJ + ";)L" + OBJ + ";"; 74 private static final String LLV_SIG = "(L" + OBJ + ";L" + OBJ + ";)V"; 75 private static final String CLASS_PREFIX = LF + "$"; 76 private static final String SOURCE_PREFIX = "LambdaForm$"; 77 78 /** Name of its super class*/ 79 static final String INVOKER_SUPER_NAME = OBJ; 80 81 /** Name of new class */ 82 private final String className; 83 84 private final LambdaForm lambdaForm; 85 private final String invokerName; 86 private final MethodType invokerType; 87 88 /** Info about local variables in compiled lambda form */ 89 private int[] localsMap; // index 90 private Class<?>[] localClasses; // type 91 92 /** ASM bytecode generation. */ 93 private ClassWriter cw; 94 private MethodVisitor mv; 95 96 /** Single element internal class name lookup cache. */ 97 private Class<?> lastClass; 98 private String lastInternalName; 99 100 private static final MemberName.Factory MEMBERNAME_FACTORY = MemberName.getFactory(); 101 private static final Class<?> HOST_CLASS = LambdaForm.class; 102 103 /** Main constructor; other constructors delegate to this one. */ InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize, String className, String invokerName, MethodType invokerType)104 private InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize, 105 String className, String invokerName, MethodType invokerType) { 106 int p = invokerName.indexOf('.'); 107 if (p > -1) { 108 className = invokerName.substring(0, p); 109 invokerName = invokerName.substring(p + 1); 110 } 111 if (DUMP_CLASS_FILES) { 112 className = makeDumpableClassName(className); 113 } 114 this.className = className; 115 this.lambdaForm = lambdaForm; 116 this.invokerName = invokerName; 117 this.invokerType = invokerType; 118 this.localsMap = new int[localsMapSize+1]; // last entry of localsMap is count of allocated local slots 119 this.localClasses = new Class<?>[localsMapSize+1]; 120 } 121 122 /** For generating LambdaForm interpreter entry points. */ InvokerBytecodeGenerator(String className, String invokerName, MethodType invokerType)123 private InvokerBytecodeGenerator(String className, String invokerName, MethodType invokerType) { 124 this(null, invokerType.parameterCount(), 125 className, invokerName, invokerType); 126 // Create an array to map name indexes to locals indexes. 127 for (int i = 0; i < localsMap.length; i++) { 128 localsMap[i] = invokerType.parameterSlotCount() - invokerType.parameterSlotDepth(i); 129 } 130 } 131 132 /** For generating customized code for a single LambdaForm. */ InvokerBytecodeGenerator(String className, LambdaForm form, MethodType invokerType)133 private InvokerBytecodeGenerator(String className, LambdaForm form, MethodType invokerType) { 134 this(className, form.lambdaName(), form, invokerType); 135 } 136 137 /** For generating customized code for a single LambdaForm. */ InvokerBytecodeGenerator(String className, String invokerName, LambdaForm form, MethodType invokerType)138 InvokerBytecodeGenerator(String className, String invokerName, 139 LambdaForm form, MethodType invokerType) { 140 this(form, form.names.length, 141 className, invokerName, invokerType); 142 // Create an array to map name indexes to locals indexes. 143 Name[] names = form.names; 144 for (int i = 0, index = 0; i < localsMap.length; i++) { 145 localsMap[i] = index; 146 if (i < names.length) { 147 BasicType type = names[i].type(); 148 index += type.basicTypeSlots(); 149 } 150 } 151 } 152 153 /** instance counters for dumped classes */ 154 private static final HashMap<String,Integer> DUMP_CLASS_FILES_COUNTERS; 155 /** debugging flag for saving generated class files */ 156 private static final File DUMP_CLASS_FILES_DIR; 157 158 static { 159 if (DUMP_CLASS_FILES) { 160 DUMP_CLASS_FILES_COUNTERS = new HashMap<>(); 161 try { 162 File dumpDir = new File("DUMP_CLASS_FILES"); 163 if (!dumpDir.exists()) { dumpDir.mkdirs()164 dumpDir.mkdirs(); 165 } 166 DUMP_CLASS_FILES_DIR = dumpDir; 167 System.out.println("Dumping class files to "+DUMP_CLASS_FILES_DIR+"/..."); 168 } catch (Exception e) { 169 throw newInternalError(e); 170 } 171 } else { 172 DUMP_CLASS_FILES_COUNTERS = null; 173 DUMP_CLASS_FILES_DIR = null; 174 } 175 } 176 maybeDump(final byte[] classFile)177 private void maybeDump(final byte[] classFile) { 178 if (DUMP_CLASS_FILES) { 179 maybeDump(CLASS_PREFIX + className, classFile); 180 } 181 } 182 183 // Also used from BoundMethodHandle maybeDump(final String className, final byte[] classFile)184 static void maybeDump(final String className, final byte[] classFile) { 185 if (DUMP_CLASS_FILES) { 186 java.security.AccessController.doPrivileged( 187 new java.security.PrivilegedAction<>() { 188 public Void run() { 189 try { 190 String dumpName = className.replace('.','/'); 191 File dumpFile = new File(DUMP_CLASS_FILES_DIR, dumpName+".class"); 192 System.out.println("dump: " + dumpFile); 193 dumpFile.getParentFile().mkdirs(); 194 FileOutputStream file = new FileOutputStream(dumpFile); 195 file.write(classFile); 196 file.close(); 197 return null; 198 } catch (IOException ex) { 199 throw newInternalError(ex); 200 } 201 } 202 }); 203 } 204 } 205 makeDumpableClassName(String className)206 private static String makeDumpableClassName(String className) { 207 Integer ctr; 208 synchronized (DUMP_CLASS_FILES_COUNTERS) { 209 ctr = DUMP_CLASS_FILES_COUNTERS.get(className); 210 if (ctr == null) ctr = 0; 211 DUMP_CLASS_FILES_COUNTERS.put(className, ctr+1); 212 } 213 String sfx = ctr.toString(); 214 while (sfx.length() < 3) 215 sfx = "0"+sfx; 216 className += sfx; 217 return className; 218 } 219 220 class CpPatch { 221 final int index; 222 final Object value; CpPatch(int index, Object value)223 CpPatch(int index, Object value) { 224 this.index = index; 225 this.value = value; 226 } toString()227 public String toString() { 228 return "CpPatch/index="+index+",value="+value; 229 } 230 } 231 232 private final ArrayList<CpPatch> cpPatches = new ArrayList<>(); 233 234 private int cph = 0; // for counting constant placeholders 235 constantPlaceholder(Object arg)236 String constantPlaceholder(Object arg) { 237 String cpPlaceholder = "CONSTANT_PLACEHOLDER_" + cph++; 238 if (DUMP_CLASS_FILES) cpPlaceholder += " <<" + debugString(arg) + ">>"; 239 // TODO check if arg is already in the constant pool 240 // insert placeholder in CP and remember the patch 241 int index = cw.newConst((Object) cpPlaceholder); 242 cpPatches.add(new CpPatch(index, arg)); 243 return cpPlaceholder; 244 } 245 cpPatches(byte[] classFile)246 Object[] cpPatches(byte[] classFile) { 247 int size = getConstantPoolSize(classFile); 248 Object[] res = new Object[size]; 249 for (CpPatch p : cpPatches) { 250 if (p.index >= size) 251 throw new InternalError("in cpool["+size+"]: "+p+"\n"+Arrays.toString(Arrays.copyOf(classFile, 20))); 252 res[p.index] = p.value; 253 } 254 return res; 255 } 256 debugString(Object arg)257 private static String debugString(Object arg) { 258 if (arg instanceof MethodHandle) { 259 MethodHandle mh = (MethodHandle) arg; 260 MemberName member = mh.internalMemberName(); 261 if (member != null) 262 return member.toString(); 263 return mh.debugString(); 264 } 265 return arg.toString(); 266 } 267 268 /** 269 * Extract the number of constant pool entries from a given class file. 270 * 271 * @param classFile the bytes of the class file in question. 272 * @return the number of entries in the constant pool. 273 */ getConstantPoolSize(byte[] classFile)274 private static int getConstantPoolSize(byte[] classFile) { 275 // The first few bytes: 276 // u4 magic; 277 // u2 minor_version; 278 // u2 major_version; 279 // u2 constant_pool_count; 280 return ((classFile[8] & 0xFF) << 8) | (classFile[9] & 0xFF); 281 } 282 283 /** 284 * Extract the MemberName of a newly-defined method. 285 */ loadMethod(byte[] classFile)286 private MemberName loadMethod(byte[] classFile) { 287 Class<?> invokerClass = loadAndInitializeInvokerClass(classFile, cpPatches(classFile)); 288 return resolveInvokerMember(invokerClass, invokerName, invokerType); 289 } 290 291 /** 292 * Define a given class as anonymous class in the runtime system. 293 */ loadAndInitializeInvokerClass(byte[] classBytes, Object[] patches)294 private static Class<?> loadAndInitializeInvokerClass(byte[] classBytes, Object[] patches) { 295 Class<?> invokerClass = UNSAFE.defineAnonymousClass(HOST_CLASS, classBytes, patches); 296 UNSAFE.ensureClassInitialized(invokerClass); // Make sure the class is initialized; VM might complain. 297 return invokerClass; 298 } 299 resolveInvokerMember(Class<?> invokerClass, String name, MethodType type)300 private static MemberName resolveInvokerMember(Class<?> invokerClass, String name, MethodType type) { 301 MemberName member = new MemberName(invokerClass, name, type, REF_invokeStatic); 302 try { 303 member = MEMBERNAME_FACTORY.resolveOrFail(REF_invokeStatic, member, HOST_CLASS, ReflectiveOperationException.class); 304 } catch (ReflectiveOperationException e) { 305 throw newInternalError(e); 306 } 307 return member; 308 } 309 310 /** 311 * Set up class file generation. 312 */ classFilePrologue()313 private ClassWriter classFilePrologue() { 314 final int NOT_ACC_PUBLIC = 0; // not ACC_PUBLIC 315 cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES); 316 cw.visit(Opcodes.V1_8, NOT_ACC_PUBLIC + Opcodes.ACC_FINAL + Opcodes.ACC_SUPER, 317 CLASS_PREFIX + className, null, INVOKER_SUPER_NAME, null); 318 cw.visitSource(SOURCE_PREFIX + className, null); 319 return cw; 320 } 321 methodPrologue()322 private void methodPrologue() { 323 String invokerDesc = invokerType.toMethodDescriptorString(); 324 mv = cw.visitMethod(Opcodes.ACC_STATIC, invokerName, invokerDesc, null, null); 325 } 326 327 /** 328 * Tear down class file generation. 329 */ methodEpilogue()330 private void methodEpilogue() { 331 mv.visitMaxs(0, 0); 332 mv.visitEnd(); 333 } 334 335 /* 336 * Low-level emit helpers. 337 */ emitConst(Object con)338 private void emitConst(Object con) { 339 if (con == null) { 340 mv.visitInsn(Opcodes.ACONST_NULL); 341 return; 342 } 343 if (con instanceof Integer) { 344 emitIconstInsn((int) con); 345 return; 346 } 347 if (con instanceof Byte) { 348 emitIconstInsn((byte)con); 349 return; 350 } 351 if (con instanceof Short) { 352 emitIconstInsn((short)con); 353 return; 354 } 355 if (con instanceof Character) { 356 emitIconstInsn((char)con); 357 return; 358 } 359 if (con instanceof Long) { 360 long x = (long) con; 361 short sx = (short)x; 362 if (x == sx) { 363 if (sx >= 0 && sx <= 1) { 364 mv.visitInsn(Opcodes.LCONST_0 + (int) sx); 365 } else { 366 emitIconstInsn((int) x); 367 mv.visitInsn(Opcodes.I2L); 368 } 369 return; 370 } 371 } 372 if (con instanceof Float) { 373 float x = (float) con; 374 short sx = (short)x; 375 if (x == sx) { 376 if (sx >= 0 && sx <= 2) { 377 mv.visitInsn(Opcodes.FCONST_0 + (int) sx); 378 } else { 379 emitIconstInsn((int) x); 380 mv.visitInsn(Opcodes.I2F); 381 } 382 return; 383 } 384 } 385 if (con instanceof Double) { 386 double x = (double) con; 387 short sx = (short)x; 388 if (x == sx) { 389 if (sx >= 0 && sx <= 1) { 390 mv.visitInsn(Opcodes.DCONST_0 + (int) sx); 391 } else { 392 emitIconstInsn((int) x); 393 mv.visitInsn(Opcodes.I2D); 394 } 395 return; 396 } 397 } 398 if (con instanceof Boolean) { 399 emitIconstInsn((boolean) con ? 1 : 0); 400 return; 401 } 402 // fall through: 403 mv.visitLdcInsn(con); 404 } 405 emitIconstInsn(final int cst)406 private void emitIconstInsn(final int cst) { 407 if (cst >= -1 && cst <= 5) { 408 mv.visitInsn(Opcodes.ICONST_0 + cst); 409 } else if (cst >= Byte.MIN_VALUE && cst <= Byte.MAX_VALUE) { 410 mv.visitIntInsn(Opcodes.BIPUSH, cst); 411 } else if (cst >= Short.MIN_VALUE && cst <= Short.MAX_VALUE) { 412 mv.visitIntInsn(Opcodes.SIPUSH, cst); 413 } else { 414 mv.visitLdcInsn(cst); 415 } 416 } 417 418 /* 419 * NOTE: These load/store methods use the localsMap to find the correct index! 420 */ emitLoadInsn(BasicType type, int index)421 private void emitLoadInsn(BasicType type, int index) { 422 int opcode = loadInsnOpcode(type); 423 mv.visitVarInsn(opcode, localsMap[index]); 424 } 425 loadInsnOpcode(BasicType type)426 private int loadInsnOpcode(BasicType type) throws InternalError { 427 switch (type) { 428 case I_TYPE: return Opcodes.ILOAD; 429 case J_TYPE: return Opcodes.LLOAD; 430 case F_TYPE: return Opcodes.FLOAD; 431 case D_TYPE: return Opcodes.DLOAD; 432 case L_TYPE: return Opcodes.ALOAD; 433 default: 434 throw new InternalError("unknown type: " + type); 435 } 436 } emitAloadInsn(int index)437 private void emitAloadInsn(int index) { 438 emitLoadInsn(L_TYPE, index); 439 } 440 emitStoreInsn(BasicType type, int index)441 private void emitStoreInsn(BasicType type, int index) { 442 int opcode = storeInsnOpcode(type); 443 mv.visitVarInsn(opcode, localsMap[index]); 444 } 445 storeInsnOpcode(BasicType type)446 private int storeInsnOpcode(BasicType type) throws InternalError { 447 switch (type) { 448 case I_TYPE: return Opcodes.ISTORE; 449 case J_TYPE: return Opcodes.LSTORE; 450 case F_TYPE: return Opcodes.FSTORE; 451 case D_TYPE: return Opcodes.DSTORE; 452 case L_TYPE: return Opcodes.ASTORE; 453 default: 454 throw new InternalError("unknown type: " + type); 455 } 456 } emitAstoreInsn(int index)457 private void emitAstoreInsn(int index) { 458 emitStoreInsn(L_TYPE, index); 459 } 460 arrayTypeCode(Wrapper elementType)461 private byte arrayTypeCode(Wrapper elementType) { 462 switch (elementType) { 463 case BOOLEAN: return Opcodes.T_BOOLEAN; 464 case BYTE: return Opcodes.T_BYTE; 465 case CHAR: return Opcodes.T_CHAR; 466 case SHORT: return Opcodes.T_SHORT; 467 case INT: return Opcodes.T_INT; 468 case LONG: return Opcodes.T_LONG; 469 case FLOAT: return Opcodes.T_FLOAT; 470 case DOUBLE: return Opcodes.T_DOUBLE; 471 case OBJECT: return 0; // in place of Opcodes.T_OBJECT 472 default: throw new InternalError(); 473 } 474 } 475 arrayInsnOpcode(byte tcode, int aaop)476 private int arrayInsnOpcode(byte tcode, int aaop) throws InternalError { 477 assert(aaop == Opcodes.AASTORE || aaop == Opcodes.AALOAD); 478 int xas; 479 switch (tcode) { 480 case Opcodes.T_BOOLEAN: xas = Opcodes.BASTORE; break; 481 case Opcodes.T_BYTE: xas = Opcodes.BASTORE; break; 482 case Opcodes.T_CHAR: xas = Opcodes.CASTORE; break; 483 case Opcodes.T_SHORT: xas = Opcodes.SASTORE; break; 484 case Opcodes.T_INT: xas = Opcodes.IASTORE; break; 485 case Opcodes.T_LONG: xas = Opcodes.LASTORE; break; 486 case Opcodes.T_FLOAT: xas = Opcodes.FASTORE; break; 487 case Opcodes.T_DOUBLE: xas = Opcodes.DASTORE; break; 488 case 0: xas = Opcodes.AASTORE; break; 489 default: throw new InternalError(); 490 } 491 return xas - Opcodes.AASTORE + aaop; 492 } 493 494 /** 495 * Emit a boxing call. 496 * 497 * @param wrapper primitive type class to box. 498 */ emitBoxing(Wrapper wrapper)499 private void emitBoxing(Wrapper wrapper) { 500 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName(); 501 String name = "valueOf"; 502 String desc = "(" + wrapper.basicTypeChar() + ")L" + owner + ";"; 503 mv.visitMethodInsn(Opcodes.INVOKESTATIC, owner, name, desc, false); 504 } 505 506 /** 507 * Emit an unboxing call (plus preceding checkcast). 508 * 509 * @param wrapper wrapper type class to unbox. 510 */ emitUnboxing(Wrapper wrapper)511 private void emitUnboxing(Wrapper wrapper) { 512 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName(); 513 String name = wrapper.primitiveSimpleName() + "Value"; 514 String desc = "()" + wrapper.basicTypeChar(); 515 emitReferenceCast(wrapper.wrapperType(), null); 516 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, owner, name, desc, false); 517 } 518 519 /** 520 * Emit an implicit conversion for an argument which must be of the given pclass. 521 * This is usually a no-op, except when pclass is a subword type or a reference other than Object or an interface. 522 * 523 * @param ptype type of value present on stack 524 * @param pclass type of value required on stack 525 * @param arg compile-time representation of value on stack (Node, constant) or null if none 526 */ emitImplicitConversion(BasicType ptype, Class<?> pclass, Object arg)527 private void emitImplicitConversion(BasicType ptype, Class<?> pclass, Object arg) { 528 assert(basicType(pclass) == ptype); // boxing/unboxing handled by caller 529 if (pclass == ptype.basicTypeClass() && ptype != L_TYPE) 530 return; // nothing to do 531 switch (ptype) { 532 case L_TYPE: 533 if (VerifyType.isNullConversion(Object.class, pclass, false)) { 534 if (PROFILE_LEVEL > 0) 535 emitReferenceCast(Object.class, arg); 536 return; 537 } 538 emitReferenceCast(pclass, arg); 539 return; 540 case I_TYPE: 541 if (!VerifyType.isNullConversion(int.class, pclass, false)) 542 emitPrimCast(ptype.basicTypeWrapper(), Wrapper.forPrimitiveType(pclass)); 543 return; 544 } 545 throw newInternalError("bad implicit conversion: tc="+ptype+": "+pclass); 546 } 547 548 /** Update localClasses type map. Return true if the information is already present. */ assertStaticType(Class<?> cls, Name n)549 private boolean assertStaticType(Class<?> cls, Name n) { 550 int local = n.index(); 551 Class<?> aclass = localClasses[local]; 552 if (aclass != null && (aclass == cls || cls.isAssignableFrom(aclass))) { 553 return true; // type info is already present 554 } else if (aclass == null || aclass.isAssignableFrom(cls)) { 555 localClasses[local] = cls; // type info can be improved 556 } 557 return false; 558 } 559 emitReferenceCast(Class<?> cls, Object arg)560 private void emitReferenceCast(Class<?> cls, Object arg) { 561 Name writeBack = null; // local to write back result 562 if (arg instanceof Name) { 563 Name n = (Name) arg; 564 if (lambdaForm.useCount(n) > 1) { 565 // This guy gets used more than once. 566 writeBack = n; 567 if (assertStaticType(cls, n)) { 568 return; // this cast was already performed 569 } 570 } 571 } 572 if (isStaticallyNameable(cls)) { 573 String sig = getInternalName(cls); 574 mv.visitTypeInsn(Opcodes.CHECKCAST, sig); 575 } else { 576 mv.visitLdcInsn(constantPlaceholder(cls)); 577 mv.visitTypeInsn(Opcodes.CHECKCAST, CLS); 578 mv.visitInsn(Opcodes.SWAP); 579 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, CLS, "cast", LL_SIG, false); 580 if (Object[].class.isAssignableFrom(cls)) 581 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJARY); 582 else if (PROFILE_LEVEL > 0) 583 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJ); 584 } 585 if (writeBack != null) { 586 mv.visitInsn(Opcodes.DUP); 587 emitAstoreInsn(writeBack.index()); 588 } 589 } 590 591 /** 592 * Emits an actual return instruction conforming to the given return type. 593 */ emitReturnInsn(BasicType type)594 private void emitReturnInsn(BasicType type) { 595 int opcode; 596 switch (type) { 597 case I_TYPE: opcode = Opcodes.IRETURN; break; 598 case J_TYPE: opcode = Opcodes.LRETURN; break; 599 case F_TYPE: opcode = Opcodes.FRETURN; break; 600 case D_TYPE: opcode = Opcodes.DRETURN; break; 601 case L_TYPE: opcode = Opcodes.ARETURN; break; 602 case V_TYPE: opcode = Opcodes.RETURN; break; 603 default: 604 throw new InternalError("unknown return type: " + type); 605 } 606 mv.visitInsn(opcode); 607 } 608 getInternalName(Class<?> c)609 private String getInternalName(Class<?> c) { 610 if (c == Object.class) return OBJ; 611 else if (c == Object[].class) return OBJARY; 612 else if (c == Class.class) return CLS; 613 else if (c == MethodHandle.class) return MH; 614 assert(VerifyAccess.isTypeVisible(c, Object.class)) : c.getName(); 615 616 if (c == lastClass) { 617 return lastInternalName; 618 } 619 lastClass = c; 620 return lastInternalName = c.getName().replace('.', '/'); 621 } 622 resolveFrom(String name, MethodType type, Class<?> holder)623 private static MemberName resolveFrom(String name, MethodType type, Class<?> holder) { 624 MemberName member = new MemberName(holder, name, type, REF_invokeStatic); 625 MemberName resolvedMember = MemberName.getFactory().resolveOrNull(REF_invokeStatic, member, holder); 626 if (TRACE_RESOLVE) { 627 System.out.println("[LF_RESOLVE] " + holder.getName() + " " + name + " " + 628 shortenSignature(basicTypeSignature(type)) + (resolvedMember != null ? " (success)" : " (fail)") ); 629 } 630 return resolvedMember; 631 } 632 lookupPregenerated(LambdaForm form, MethodType invokerType)633 private static MemberName lookupPregenerated(LambdaForm form, MethodType invokerType) { 634 if (form.customized != null) { 635 // No pre-generated version for customized LF 636 return null; 637 } 638 String name = form.kind.methodName; 639 switch (form.kind) { 640 case BOUND_REINVOKER: { 641 name = name + "_" + BoundMethodHandle.speciesDataFor(form).key(); 642 return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class); 643 } 644 case DELEGATE: return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class); 645 case ZERO: // fall-through 646 case IDENTITY: { 647 name = name + "_" + form.returnType().basicTypeChar(); 648 return resolveFrom(name, invokerType, LambdaForm.Holder.class); 649 } 650 case EXACT_INVOKER: // fall-through 651 case EXACT_LINKER: // fall-through 652 case LINK_TO_CALL_SITE: // fall-through 653 case LINK_TO_TARGET_METHOD: // fall-through 654 case GENERIC_INVOKER: // fall-through 655 case GENERIC_LINKER: return resolveFrom(name, invokerType.basicType(), Invokers.Holder.class); 656 case GET_OBJECT: // fall-through 657 case GET_BOOLEAN: // fall-through 658 case GET_BYTE: // fall-through 659 case GET_CHAR: // fall-through 660 case GET_SHORT: // fall-through 661 case GET_INT: // fall-through 662 case GET_LONG: // fall-through 663 case GET_FLOAT: // fall-through 664 case GET_DOUBLE: // fall-through 665 case PUT_OBJECT: // fall-through 666 case PUT_BOOLEAN: // fall-through 667 case PUT_BYTE: // fall-through 668 case PUT_CHAR: // fall-through 669 case PUT_SHORT: // fall-through 670 case PUT_INT: // fall-through 671 case PUT_LONG: // fall-through 672 case PUT_FLOAT: // fall-through 673 case PUT_DOUBLE: // fall-through 674 case DIRECT_NEW_INVOKE_SPECIAL: // fall-through 675 case DIRECT_INVOKE_INTERFACE: // fall-through 676 case DIRECT_INVOKE_SPECIAL: // fall-through 677 case DIRECT_INVOKE_SPECIAL_IFC: // fall-through 678 case DIRECT_INVOKE_STATIC: // fall-through 679 case DIRECT_INVOKE_STATIC_INIT: // fall-through 680 case DIRECT_INVOKE_VIRTUAL: return resolveFrom(name, invokerType, DirectMethodHandle.Holder.class); 681 } 682 return null; 683 } 684 685 /** 686 * Generate customized bytecode for a given LambdaForm. 687 */ generateCustomizedCode(LambdaForm form, MethodType invokerType)688 static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) { 689 MemberName pregenerated = lookupPregenerated(form, invokerType); 690 if (pregenerated != null) return pregenerated; // pre-generated bytecode 691 692 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("MH", form, invokerType); 693 return g.loadMethod(g.generateCustomizedCodeBytes()); 694 } 695 696 /** Generates code to check that actual receiver and LambdaForm matches */ checkActualReceiver()697 private boolean checkActualReceiver() { 698 // Expects MethodHandle on the stack and actual receiver MethodHandle in slot #0 699 mv.visitInsn(Opcodes.DUP); 700 mv.visitVarInsn(Opcodes.ALOAD, localsMap[0]); 701 mv.visitMethodInsn(Opcodes.INVOKESTATIC, MHI, "assertSame", LLV_SIG, false); 702 return true; 703 } 704 className(String cn)705 static String className(String cn) { 706 assert checkClassName(cn): "Class not found: " + cn; 707 return cn; 708 } 709 checkClassName(String cn)710 static boolean checkClassName(String cn) { 711 Type tp = Type.getType(cn); 712 // additional sanity so only valid "L;" descriptors work 713 if (tp.getSort() != Type.OBJECT) { 714 return false; 715 } 716 try { 717 Class<?> c = Class.forName(tp.getClassName(), false, null); 718 return true; 719 } catch (ClassNotFoundException e) { 720 return false; 721 } 722 } 723 724 static final String LF_HIDDEN_SIG = className("Ljava/lang/invoke/LambdaForm$Hidden;"); 725 static final String LF_COMPILED_SIG = className("Ljava/lang/invoke/LambdaForm$Compiled;"); 726 static final String FORCEINLINE_SIG = className("Ljdk/internal/vm/annotation/ForceInline;"); 727 static final String DONTINLINE_SIG = className("Ljdk/internal/vm/annotation/DontInline;"); 728 static final String INJECTEDPROFILE_SIG = className("Ljava/lang/invoke/InjectedProfile;"); 729 730 /** 731 * Generate an invoker method for the passed {@link LambdaForm}. 732 */ generateCustomizedCodeBytes()733 private byte[] generateCustomizedCodeBytes() { 734 classFilePrologue(); 735 addMethod(); 736 bogusMethod(lambdaForm); 737 738 final byte[] classFile = toByteArray(); 739 maybeDump(classFile); 740 return classFile; 741 } 742 setClassWriter(ClassWriter cw)743 void setClassWriter(ClassWriter cw) { 744 this.cw = cw; 745 } 746 addMethod()747 void addMethod() { 748 methodPrologue(); 749 750 // Suppress this method in backtraces displayed to the user. 751 mv.visitAnnotation(LF_HIDDEN_SIG, true); 752 753 // Mark this method as a compiled LambdaForm 754 mv.visitAnnotation(LF_COMPILED_SIG, true); 755 756 if (lambdaForm.forceInline) { 757 // Force inlining of this invoker method. 758 mv.visitAnnotation(FORCEINLINE_SIG, true); 759 } else { 760 mv.visitAnnotation(DONTINLINE_SIG, true); 761 } 762 763 constantPlaceholder(lambdaForm); // keep LambdaForm instance & its compiled form lifetime tightly coupled. 764 765 if (lambdaForm.customized != null) { 766 // Since LambdaForm is customized for a particular MethodHandle, it's safe to substitute 767 // receiver MethodHandle (at slot #0) with an embedded constant and use it instead. 768 // It enables more efficient code generation in some situations, since embedded constants 769 // are compile-time constants for JIT compiler. 770 mv.visitLdcInsn(constantPlaceholder(lambdaForm.customized)); 771 mv.visitTypeInsn(Opcodes.CHECKCAST, MH); 772 assert(checkActualReceiver()); // expects MethodHandle on top of the stack 773 mv.visitVarInsn(Opcodes.ASTORE, localsMap[0]); 774 } 775 776 // iterate over the form's names, generating bytecode instructions for each 777 // start iterating at the first name following the arguments 778 Name onStack = null; 779 for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) { 780 Name name = lambdaForm.names[i]; 781 782 emitStoreResult(onStack); 783 onStack = name; // unless otherwise modified below 784 MethodHandleImpl.Intrinsic intr = name.function.intrinsicName(); 785 switch (intr) { 786 case SELECT_ALTERNATIVE: 787 assert lambdaForm.isSelectAlternative(i); 788 if (PROFILE_GWT) { 789 assert(name.arguments[0] instanceof Name && 790 ((Name)name.arguments[0]).refersTo(MethodHandleImpl.class, "profileBoolean")); 791 mv.visitAnnotation(INJECTEDPROFILE_SIG, true); 792 } 793 onStack = emitSelectAlternative(name, lambdaForm.names[i+1]); 794 i++; // skip MH.invokeBasic of the selectAlternative result 795 continue; 796 case GUARD_WITH_CATCH: 797 assert lambdaForm.isGuardWithCatch(i); 798 onStack = emitGuardWithCatch(i); 799 i += 2; // jump to the end of GWC idiom 800 continue; 801 case TRY_FINALLY: 802 assert lambdaForm.isTryFinally(i); 803 onStack = emitTryFinally(i); 804 i += 2; // jump to the end of the TF idiom 805 continue; 806 case LOOP: 807 assert lambdaForm.isLoop(i); 808 onStack = emitLoop(i); 809 i += 2; // jump to the end of the LOOP idiom 810 continue; 811 case NEW_ARRAY: 812 Class<?> rtype = name.function.methodType().returnType(); 813 if (isStaticallyNameable(rtype)) { 814 emitNewArray(name); 815 continue; 816 } 817 break; 818 case ARRAY_LOAD: 819 emitArrayLoad(name); 820 continue; 821 case ARRAY_STORE: 822 emitArrayStore(name); 823 continue; 824 case ARRAY_LENGTH: 825 emitArrayLength(name); 826 continue; 827 case IDENTITY: 828 assert(name.arguments.length == 1); 829 emitPushArguments(name, 0); 830 continue; 831 case ZERO: 832 assert(name.arguments.length == 0); 833 emitConst(name.type.basicTypeWrapper().zero()); 834 continue; 835 case NONE: 836 // no intrinsic associated 837 break; 838 default: 839 throw newInternalError("Unknown intrinsic: "+intr); 840 } 841 842 MemberName member = name.function.member(); 843 if (isStaticallyInvocable(member)) { 844 emitStaticInvoke(member, name); 845 } else { 846 emitInvoke(name); 847 } 848 } 849 850 // return statement 851 emitReturn(onStack); 852 853 methodEpilogue(); 854 } 855 856 /* 857 * @throws BytecodeGenerationException if something goes wrong when 858 * generating the byte code 859 */ toByteArray()860 private byte[] toByteArray() { 861 try { 862 return cw.toByteArray(); 863 } catch (RuntimeException e) { 864 throw new BytecodeGenerationException(e); 865 } 866 } 867 868 @SuppressWarnings("serial") 869 static final class BytecodeGenerationException extends RuntimeException { BytecodeGenerationException(Exception cause)870 BytecodeGenerationException(Exception cause) { 871 super(cause); 872 } 873 } 874 emitArrayLoad(Name name)875 void emitArrayLoad(Name name) { emitArrayOp(name, Opcodes.AALOAD); } emitArrayStore(Name name)876 void emitArrayStore(Name name) { emitArrayOp(name, Opcodes.AASTORE); } emitArrayLength(Name name)877 void emitArrayLength(Name name) { emitArrayOp(name, Opcodes.ARRAYLENGTH); } 878 emitArrayOp(Name name, int arrayOpcode)879 void emitArrayOp(Name name, int arrayOpcode) { 880 assert arrayOpcode == Opcodes.AALOAD || arrayOpcode == Opcodes.AASTORE || arrayOpcode == Opcodes.ARRAYLENGTH; 881 Class<?> elementType = name.function.methodType().parameterType(0).getComponentType(); 882 assert elementType != null; 883 emitPushArguments(name, 0); 884 if (arrayOpcode != Opcodes.ARRAYLENGTH && elementType.isPrimitive()) { 885 Wrapper w = Wrapper.forPrimitiveType(elementType); 886 arrayOpcode = arrayInsnOpcode(arrayTypeCode(w), arrayOpcode); 887 } 888 mv.visitInsn(arrayOpcode); 889 } 890 891 /** 892 * Emit an invoke for the given name. 893 */ emitInvoke(Name name)894 void emitInvoke(Name name) { 895 assert(!name.isLinkerMethodInvoke()); // should use the static path for these 896 if (true) { 897 // push receiver 898 MethodHandle target = name.function.resolvedHandle(); 899 assert(target != null) : name.exprString(); 900 mv.visitLdcInsn(constantPlaceholder(target)); 901 emitReferenceCast(MethodHandle.class, target); 902 } else { 903 // load receiver 904 emitAloadInsn(0); 905 emitReferenceCast(MethodHandle.class, null); 906 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", LF_SIG); 907 mv.visitFieldInsn(Opcodes.GETFIELD, LF, "names", LFN_SIG); 908 // TODO more to come 909 } 910 911 // push arguments 912 emitPushArguments(name, 0); 913 914 // invocation 915 MethodType type = name.function.methodType(); 916 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false); 917 } 918 919 private static Class<?>[] STATICALLY_INVOCABLE_PACKAGES = { 920 // Sample classes from each package we are willing to bind to statically: 921 java.lang.Object.class, 922 java.util.Arrays.class, 923 jdk.internal.misc.Unsafe.class 924 //MethodHandle.class already covered 925 }; 926 isStaticallyInvocable(NamedFunction .... functions)927 static boolean isStaticallyInvocable(NamedFunction ... functions) { 928 for (NamedFunction nf : functions) { 929 if (!isStaticallyInvocable(nf.member())) { 930 return false; 931 } 932 } 933 return true; 934 } 935 isStaticallyInvocable(Name name)936 static boolean isStaticallyInvocable(Name name) { 937 return isStaticallyInvocable(name.function.member()); 938 } 939 isStaticallyInvocable(MemberName member)940 static boolean isStaticallyInvocable(MemberName member) { 941 if (member == null) return false; 942 if (member.isConstructor()) return false; 943 Class<?> cls = member.getDeclaringClass(); 944 // Fast-path non-private members declared by MethodHandles, which is a common 945 // case 946 if (MethodHandle.class.isAssignableFrom(cls) && !member.isPrivate()) { 947 assert(isStaticallyInvocableType(member.getMethodOrFieldType())); 948 return true; 949 } 950 if (cls.isArray() || cls.isPrimitive()) 951 return false; // FIXME 952 if (cls.isAnonymousClass() || cls.isLocalClass()) 953 return false; // inner class of some sort 954 if (cls.getClassLoader() != MethodHandle.class.getClassLoader()) 955 return false; // not on BCP 956 if (ReflectUtil.isVMAnonymousClass(cls)) // FIXME: switch to supported API once it is added 957 return false; 958 if (!isStaticallyInvocableType(member.getMethodOrFieldType())) 959 return false; 960 if (!member.isPrivate() && VerifyAccess.isSamePackage(MethodHandle.class, cls)) 961 return true; // in java.lang.invoke package 962 if (member.isPublic() && isStaticallyNameable(cls)) 963 return true; 964 return false; 965 } 966 isStaticallyInvocableType(MethodType mtype)967 private static boolean isStaticallyInvocableType(MethodType mtype) { 968 if (!isStaticallyNameable(mtype.returnType())) 969 return false; 970 for (Class<?> ptype : mtype.parameterArray()) 971 if (!isStaticallyNameable(ptype)) 972 return false; 973 return true; 974 } 975 isStaticallyNameable(Class<?> cls)976 static boolean isStaticallyNameable(Class<?> cls) { 977 if (cls == Object.class) 978 return true; 979 if (MethodHandle.class.isAssignableFrom(cls)) { 980 assert(!ReflectUtil.isVMAnonymousClass(cls)); 981 return true; 982 } 983 while (cls.isArray()) 984 cls = cls.getComponentType(); 985 if (cls.isPrimitive()) 986 return true; // int[].class, for example 987 if (ReflectUtil.isVMAnonymousClass(cls)) // FIXME: switch to supported API once it is added 988 return false; 989 // could use VerifyAccess.isClassAccessible but the following is a safe approximation 990 if (cls.getClassLoader() != Object.class.getClassLoader()) 991 return false; 992 if (VerifyAccess.isSamePackage(MethodHandle.class, cls)) 993 return true; 994 if (!Modifier.isPublic(cls.getModifiers())) 995 return false; 996 for (Class<?> pkgcls : STATICALLY_INVOCABLE_PACKAGES) { 997 if (VerifyAccess.isSamePackage(pkgcls, cls)) 998 return true; 999 } 1000 return false; 1001 } 1002 emitStaticInvoke(Name name)1003 void emitStaticInvoke(Name name) { 1004 emitStaticInvoke(name.function.member(), name); 1005 } 1006 1007 /** 1008 * Emit an invoke for the given name, using the MemberName directly. 1009 */ emitStaticInvoke(MemberName member, Name name)1010 void emitStaticInvoke(MemberName member, Name name) { 1011 assert(member.equals(name.function.member())); 1012 Class<?> defc = member.getDeclaringClass(); 1013 String cname = getInternalName(defc); 1014 String mname = member.getName(); 1015 String mtype; 1016 byte refKind = member.getReferenceKind(); 1017 if (refKind == REF_invokeSpecial) { 1018 // in order to pass the verifier, we need to convert this to invokevirtual in all cases 1019 assert(member.canBeStaticallyBound()) : member; 1020 refKind = REF_invokeVirtual; 1021 } 1022 1023 assert(!(member.getDeclaringClass().isInterface() && refKind == REF_invokeVirtual)); 1024 1025 // push arguments 1026 emitPushArguments(name, 0); 1027 1028 // invocation 1029 if (member.isMethod()) { 1030 mtype = member.getMethodType().toMethodDescriptorString(); 1031 mv.visitMethodInsn(refKindOpcode(refKind), cname, mname, mtype, 1032 member.getDeclaringClass().isInterface()); 1033 } else { 1034 mtype = MethodType.toFieldDescriptorString(member.getFieldType()); 1035 mv.visitFieldInsn(refKindOpcode(refKind), cname, mname, mtype); 1036 } 1037 // Issue a type assertion for the result, so we can avoid casts later. 1038 if (name.type == L_TYPE) { 1039 Class<?> rtype = member.getInvocationType().returnType(); 1040 assert(!rtype.isPrimitive()); 1041 if (rtype != Object.class && !rtype.isInterface()) { 1042 assertStaticType(rtype, name); 1043 } 1044 } 1045 } 1046 emitNewArray(Name name)1047 void emitNewArray(Name name) throws InternalError { 1048 Class<?> rtype = name.function.methodType().returnType(); 1049 if (name.arguments.length == 0) { 1050 // The array will be a constant. 1051 Object emptyArray; 1052 try { 1053 emptyArray = name.function.resolvedHandle().invoke(); 1054 } catch (Throwable ex) { 1055 throw uncaughtException(ex); 1056 } 1057 assert(java.lang.reflect.Array.getLength(emptyArray) == 0); 1058 assert(emptyArray.getClass() == rtype); // exact typing 1059 mv.visitLdcInsn(constantPlaceholder(emptyArray)); 1060 emitReferenceCast(rtype, emptyArray); 1061 return; 1062 } 1063 Class<?> arrayElementType = rtype.getComponentType(); 1064 assert(arrayElementType != null); 1065 emitIconstInsn(name.arguments.length); 1066 int xas = Opcodes.AASTORE; 1067 if (!arrayElementType.isPrimitive()) { 1068 mv.visitTypeInsn(Opcodes.ANEWARRAY, getInternalName(arrayElementType)); 1069 } else { 1070 byte tc = arrayTypeCode(Wrapper.forPrimitiveType(arrayElementType)); 1071 xas = arrayInsnOpcode(tc, xas); 1072 mv.visitIntInsn(Opcodes.NEWARRAY, tc); 1073 } 1074 // store arguments 1075 for (int i = 0; i < name.arguments.length; i++) { 1076 mv.visitInsn(Opcodes.DUP); 1077 emitIconstInsn(i); 1078 emitPushArgument(name, i); 1079 mv.visitInsn(xas); 1080 } 1081 // the array is left on the stack 1082 assertStaticType(rtype, name); 1083 } refKindOpcode(byte refKind)1084 int refKindOpcode(byte refKind) { 1085 switch (refKind) { 1086 case REF_invokeVirtual: return Opcodes.INVOKEVIRTUAL; 1087 case REF_invokeStatic: return Opcodes.INVOKESTATIC; 1088 case REF_invokeSpecial: return Opcodes.INVOKESPECIAL; 1089 case REF_invokeInterface: return Opcodes.INVOKEINTERFACE; 1090 case REF_getField: return Opcodes.GETFIELD; 1091 case REF_putField: return Opcodes.PUTFIELD; 1092 case REF_getStatic: return Opcodes.GETSTATIC; 1093 case REF_putStatic: return Opcodes.PUTSTATIC; 1094 } 1095 throw new InternalError("refKind="+refKind); 1096 } 1097 1098 /** 1099 * Emit bytecode for the selectAlternative idiom. 1100 * 1101 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithTest): 1102 * <blockquote><pre>{@code 1103 * Lambda(a0:L,a1:I)=>{ 1104 * t2:I=foo.test(a1:I); 1105 * t3:L=MethodHandleImpl.selectAlternative(t2:I,(MethodHandle(int)int),(MethodHandle(int)int)); 1106 * t4:I=MethodHandle.invokeBasic(t3:L,a1:I);t4:I} 1107 * }</pre></blockquote> 1108 */ emitSelectAlternative(Name selectAlternativeName, Name invokeBasicName)1109 private Name emitSelectAlternative(Name selectAlternativeName, Name invokeBasicName) { 1110 assert isStaticallyInvocable(invokeBasicName); 1111 1112 Name receiver = (Name) invokeBasicName.arguments[0]; 1113 1114 Label L_fallback = new Label(); 1115 Label L_done = new Label(); 1116 1117 // load test result 1118 emitPushArgument(selectAlternativeName, 0); 1119 1120 // if_icmpne L_fallback 1121 mv.visitJumpInsn(Opcodes.IFEQ, L_fallback); 1122 1123 // invoke selectAlternativeName.arguments[1] 1124 Class<?>[] preForkClasses = localClasses.clone(); 1125 emitPushArgument(selectAlternativeName, 1); // get 2nd argument of selectAlternative 1126 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot 1127 emitStaticInvoke(invokeBasicName); 1128 1129 // goto L_done 1130 mv.visitJumpInsn(Opcodes.GOTO, L_done); 1131 1132 // L_fallback: 1133 mv.visitLabel(L_fallback); 1134 1135 // invoke selectAlternativeName.arguments[2] 1136 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length); 1137 emitPushArgument(selectAlternativeName, 2); // get 3rd argument of selectAlternative 1138 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot 1139 emitStaticInvoke(invokeBasicName); 1140 1141 // L_done: 1142 mv.visitLabel(L_done); 1143 // for now do not bother to merge typestate; just reset to the dominator state 1144 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length); 1145 1146 return invokeBasicName; // return what's on stack 1147 } 1148 1149 /** 1150 * Emit bytecode for the guardWithCatch idiom. 1151 * 1152 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithCatch): 1153 * <blockquote><pre>{@code 1154 * guardWithCatch=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{ 1155 * t8:L=MethodHandle.invokeBasic(a4:L,a6:L,a7:L); 1156 * t9:L=MethodHandleImpl.guardWithCatch(a1:L,a2:L,a3:L,t8:L); 1157 * t10:I=MethodHandle.invokeBasic(a5:L,t9:L);t10:I} 1158 * }</pre></blockquote> 1159 * 1160 * It is compiled into bytecode equivalent of the following code: 1161 * <blockquote><pre>{@code 1162 * try { 1163 * return a1.invokeBasic(a6, a7); 1164 * } catch (Throwable e) { 1165 * if (!a2.isInstance(e)) throw e; 1166 * return a3.invokeBasic(ex, a6, a7); 1167 * }}</pre></blockquote> 1168 */ emitGuardWithCatch(int pos)1169 private Name emitGuardWithCatch(int pos) { 1170 Name args = lambdaForm.names[pos]; 1171 Name invoker = lambdaForm.names[pos+1]; 1172 Name result = lambdaForm.names[pos+2]; 1173 1174 Label L_startBlock = new Label(); 1175 Label L_endBlock = new Label(); 1176 Label L_handler = new Label(); 1177 Label L_done = new Label(); 1178 1179 Class<?> returnType = result.function.resolvedHandle().type().returnType(); 1180 MethodType type = args.function.resolvedHandle().type() 1181 .dropParameterTypes(0,1) 1182 .changeReturnType(returnType); 1183 1184 mv.visitTryCatchBlock(L_startBlock, L_endBlock, L_handler, "java/lang/Throwable"); 1185 1186 // Normal case 1187 mv.visitLabel(L_startBlock); 1188 // load target 1189 emitPushArgument(invoker, 0); 1190 emitPushArguments(args, 1); // skip 1st argument: method handle 1191 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false); 1192 mv.visitLabel(L_endBlock); 1193 mv.visitJumpInsn(Opcodes.GOTO, L_done); 1194 1195 // Exceptional case 1196 mv.visitLabel(L_handler); 1197 1198 // Check exception's type 1199 mv.visitInsn(Opcodes.DUP); 1200 // load exception class 1201 emitPushArgument(invoker, 1); 1202 mv.visitInsn(Opcodes.SWAP); 1203 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Class", "isInstance", "(Ljava/lang/Object;)Z", false); 1204 Label L_rethrow = new Label(); 1205 mv.visitJumpInsn(Opcodes.IFEQ, L_rethrow); 1206 1207 // Invoke catcher 1208 // load catcher 1209 emitPushArgument(invoker, 2); 1210 mv.visitInsn(Opcodes.SWAP); 1211 emitPushArguments(args, 1); // skip 1st argument: method handle 1212 MethodType catcherType = type.insertParameterTypes(0, Throwable.class); 1213 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", catcherType.basicType().toMethodDescriptorString(), false); 1214 mv.visitJumpInsn(Opcodes.GOTO, L_done); 1215 1216 mv.visitLabel(L_rethrow); 1217 mv.visitInsn(Opcodes.ATHROW); 1218 1219 mv.visitLabel(L_done); 1220 1221 return result; 1222 } 1223 1224 /** 1225 * Emit bytecode for the tryFinally idiom. 1226 * <p> 1227 * The pattern looks like (Cf. MethodHandleImpl.makeTryFinally): 1228 * <blockquote><pre>{@code 1229 * // a0: BMH 1230 * // a1: target, a2: cleanup 1231 * // a3: box, a4: unbox 1232 * // a5 (and following): arguments 1233 * tryFinally=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L)=>{ 1234 * t6:L=MethodHandle.invokeBasic(a3:L,a5:L); // box the arguments into an Object[] 1235 * t7:L=MethodHandleImpl.tryFinally(a1:L,a2:L,t6:L); // call the tryFinally executor 1236 * t8:L=MethodHandle.invokeBasic(a4:L,t7:L);t8:L} // unbox the result; return the result 1237 * }</pre></blockquote> 1238 * <p> 1239 * It is compiled into bytecode equivalent to the following code: 1240 * <blockquote><pre>{@code 1241 * Throwable t; 1242 * Object r; 1243 * try { 1244 * r = a1.invokeBasic(a5); 1245 * } catch (Throwable thrown) { 1246 * t = thrown; 1247 * throw t; 1248 * } finally { 1249 * r = a2.invokeBasic(t, r, a5); 1250 * } 1251 * return r; 1252 * }</pre></blockquote> 1253 * <p> 1254 * Specifically, the bytecode will have the following form (the stack effects are given for the beginnings of 1255 * blocks, and for the situations after executing the given instruction - the code will have a slightly different 1256 * shape if the return type is {@code void}): 1257 * <blockquote><pre>{@code 1258 * TRY: (--) 1259 * load target (-- target) 1260 * load args (-- args... target) 1261 * INVOKEVIRTUAL MethodHandle.invokeBasic (depends) 1262 * FINALLY_NORMAL: (-- r_2nd* r) 1263 * store returned value (--) 1264 * load cleanup (-- cleanup) 1265 * ACONST_NULL (-- t cleanup) 1266 * load returned value (-- r_2nd* r t cleanup) 1267 * load args (-- args... r_2nd* r t cleanup) 1268 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r_2nd* r) 1269 * GOTO DONE 1270 * CATCH: (-- t) 1271 * DUP (-- t t) 1272 * FINALLY_EXCEPTIONAL: (-- t t) 1273 * load cleanup (-- cleanup t t) 1274 * SWAP (-- t cleanup t) 1275 * load default for r (-- r_2nd* r t cleanup t) 1276 * load args (-- args... r_2nd* r t cleanup t) 1277 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r_2nd* r t) 1278 * POP/POP2* (-- t) 1279 * ATHROW 1280 * DONE: (-- r) 1281 * }</pre></blockquote> 1282 * * = depends on whether the return type takes up 2 stack slots. 1283 */ emitTryFinally(int pos)1284 private Name emitTryFinally(int pos) { 1285 Name args = lambdaForm.names[pos]; 1286 Name invoker = lambdaForm.names[pos+1]; 1287 Name result = lambdaForm.names[pos+2]; 1288 1289 Label lFrom = new Label(); 1290 Label lTo = new Label(); 1291 Label lCatch = new Label(); 1292 Label lDone = new Label(); 1293 1294 Class<?> returnType = result.function.resolvedHandle().type().returnType(); 1295 BasicType basicReturnType = BasicType.basicType(returnType); 1296 boolean isNonVoid = returnType != void.class; 1297 1298 MethodType type = args.function.resolvedHandle().type() 1299 .dropParameterTypes(0,1) 1300 .changeReturnType(returnType); 1301 MethodType cleanupType = type.insertParameterTypes(0, Throwable.class); 1302 if (isNonVoid) { 1303 cleanupType = cleanupType.insertParameterTypes(1, returnType); 1304 } 1305 String cleanupDesc = cleanupType.basicType().toMethodDescriptorString(); 1306 1307 // exception handler table 1308 mv.visitTryCatchBlock(lFrom, lTo, lCatch, "java/lang/Throwable"); 1309 1310 // TRY: 1311 mv.visitLabel(lFrom); 1312 emitPushArgument(invoker, 0); // load target 1313 emitPushArguments(args, 1); // load args (skip 0: method handle) 1314 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false); 1315 mv.visitLabel(lTo); 1316 1317 // FINALLY_NORMAL: 1318 int index = extendLocalsMap(new Class<?>[]{ returnType }); 1319 if (isNonVoid) { 1320 emitStoreInsn(basicReturnType, index); 1321 } 1322 emitPushArgument(invoker, 1); // load cleanup 1323 mv.visitInsn(Opcodes.ACONST_NULL); 1324 if (isNonVoid) { 1325 emitLoadInsn(basicReturnType, index); 1326 } 1327 emitPushArguments(args, 1); // load args (skip 0: method handle) 1328 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", cleanupDesc, false); 1329 mv.visitJumpInsn(Opcodes.GOTO, lDone); 1330 1331 // CATCH: 1332 mv.visitLabel(lCatch); 1333 mv.visitInsn(Opcodes.DUP); 1334 1335 // FINALLY_EXCEPTIONAL: 1336 emitPushArgument(invoker, 1); // load cleanup 1337 mv.visitInsn(Opcodes.SWAP); 1338 if (isNonVoid) { 1339 emitZero(BasicType.basicType(returnType)); // load default for result 1340 } 1341 emitPushArguments(args, 1); // load args (skip 0: method handle) 1342 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", cleanupDesc, false); 1343 if (isNonVoid) { 1344 emitPopInsn(basicReturnType); 1345 } 1346 mv.visitInsn(Opcodes.ATHROW); 1347 1348 // DONE: 1349 mv.visitLabel(lDone); 1350 1351 return result; 1352 } 1353 emitPopInsn(BasicType type)1354 private void emitPopInsn(BasicType type) { 1355 mv.visitInsn(popInsnOpcode(type)); 1356 } 1357 popInsnOpcode(BasicType type)1358 private static int popInsnOpcode(BasicType type) { 1359 switch (type) { 1360 case I_TYPE: 1361 case F_TYPE: 1362 case L_TYPE: 1363 return Opcodes.POP; 1364 case J_TYPE: 1365 case D_TYPE: 1366 return Opcodes.POP2; 1367 default: 1368 throw new InternalError("unknown type: " + type); 1369 } 1370 } 1371 1372 /** 1373 * Emit bytecode for the loop idiom. 1374 * <p> 1375 * The pattern looks like (Cf. MethodHandleImpl.loop): 1376 * <blockquote><pre>{@code 1377 * // a0: BMH 1378 * // a1: LoopClauses (containing an array of arrays: inits, steps, preds, finis) 1379 * // a2: box, a3: unbox 1380 * // a4 (and following): arguments 1381 * loop=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L)=>{ 1382 * t5:L=MethodHandle.invokeBasic(a2:L,a4:L); // box the arguments into an Object[] 1383 * t6:L=MethodHandleImpl.loop(bt:L,a1:L,t5:L); // call the loop executor (with supplied types in bt) 1384 * t7:L=MethodHandle.invokeBasic(a3:L,t6:L);t7:L} // unbox the result; return the result 1385 * }</pre></blockquote> 1386 * <p> 1387 * It is compiled into bytecode equivalent to the code seen in {@link MethodHandleImpl#loop(BasicType[], 1388 * MethodHandleImpl.LoopClauses, Object...)}, with the difference that no arrays 1389 * will be used for local state storage. Instead, the local state will be mapped to actual stack slots. 1390 * <p> 1391 * Bytecode generation applies an unrolling scheme to enable better bytecode generation regarding local state type 1392 * handling. The generated bytecode will have the following form ({@code void} types are ignored for convenience). 1393 * Assume there are {@code C} clauses in the loop. 1394 * <blockquote><pre>{@code 1395 * PREINIT: ALOAD_1 1396 * CHECKCAST LoopClauses 1397 * GETFIELD LoopClauses.clauses 1398 * ASTORE clauseDataIndex // place the clauses 2-dimensional array on the stack 1399 * INIT: (INIT_SEQ for clause 1) 1400 * ... 1401 * (INIT_SEQ for clause C) 1402 * LOOP: (LOOP_SEQ for clause 1) 1403 * ... 1404 * (LOOP_SEQ for clause C) 1405 * GOTO LOOP 1406 * DONE: ... 1407 * }</pre></blockquote> 1408 * <p> 1409 * The {@code INIT_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has 1410 * the following shape. Assume slot {@code vx} is used to hold the state for clause {@code x}. 1411 * <blockquote><pre>{@code 1412 * INIT_SEQ_x: ALOAD clauseDataIndex 1413 * ICONST_0 1414 * AALOAD // load the inits array 1415 * ICONST x 1416 * AALOAD // load the init handle for clause x 1417 * load args 1418 * INVOKEVIRTUAL MethodHandle.invokeBasic 1419 * store vx 1420 * }</pre></blockquote> 1421 * <p> 1422 * The {@code LOOP_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has 1423 * the following shape. Again, assume slot {@code vx} is used to hold the state for clause {@code x}. 1424 * <blockquote><pre>{@code 1425 * LOOP_SEQ_x: ALOAD clauseDataIndex 1426 * ICONST_1 1427 * AALOAD // load the steps array 1428 * ICONST x 1429 * AALOAD // load the step handle for clause x 1430 * load locals 1431 * load args 1432 * INVOKEVIRTUAL MethodHandle.invokeBasic 1433 * store vx 1434 * ALOAD clauseDataIndex 1435 * ICONST_2 1436 * AALOAD // load the preds array 1437 * ICONST x 1438 * AALOAD // load the pred handle for clause x 1439 * load locals 1440 * load args 1441 * INVOKEVIRTUAL MethodHandle.invokeBasic 1442 * IFNE LOOP_SEQ_x+1 // predicate returned false -> jump to next clause 1443 * ALOAD clauseDataIndex 1444 * ICONST_3 1445 * AALOAD // load the finis array 1446 * ICONST x 1447 * AALOAD // load the fini handle for clause x 1448 * load locals 1449 * load args 1450 * INVOKEVIRTUAL MethodHandle.invokeBasic 1451 * GOTO DONE // jump beyond end of clauses to return from loop 1452 * }</pre></blockquote> 1453 */ emitLoop(int pos)1454 private Name emitLoop(int pos) { 1455 Name args = lambdaForm.names[pos]; 1456 Name invoker = lambdaForm.names[pos+1]; 1457 Name result = lambdaForm.names[pos+2]; 1458 1459 // extract clause and loop-local state types 1460 // find the type info in the loop invocation 1461 BasicType[] loopClauseTypes = (BasicType[]) invoker.arguments[0]; 1462 Class<?>[] loopLocalStateTypes = Stream.of(loopClauseTypes). 1463 filter(bt -> bt != BasicType.V_TYPE).map(BasicType::basicTypeClass).toArray(Class<?>[]::new); 1464 Class<?>[] localTypes = new Class<?>[loopLocalStateTypes.length + 1]; 1465 localTypes[0] = MethodHandleImpl.LoopClauses.class; 1466 System.arraycopy(loopLocalStateTypes, 0, localTypes, 1, loopLocalStateTypes.length); 1467 1468 final int clauseDataIndex = extendLocalsMap(localTypes); 1469 final int firstLoopStateIndex = clauseDataIndex + 1; 1470 1471 Class<?> returnType = result.function.resolvedHandle().type().returnType(); 1472 MethodType loopType = args.function.resolvedHandle().type() 1473 .dropParameterTypes(0,1) 1474 .changeReturnType(returnType); 1475 MethodType loopHandleType = loopType.insertParameterTypes(0, loopLocalStateTypes); 1476 MethodType predType = loopHandleType.changeReturnType(boolean.class); 1477 MethodType finiType = loopHandleType; 1478 1479 final int nClauses = loopClauseTypes.length; 1480 1481 // indices to invoker arguments to load method handle arrays 1482 final int inits = 1; 1483 final int steps = 2; 1484 final int preds = 3; 1485 final int finis = 4; 1486 1487 Label lLoop = new Label(); 1488 Label lDone = new Label(); 1489 Label lNext; 1490 1491 // PREINIT: 1492 emitPushArgument(MethodHandleImpl.LoopClauses.class, invoker.arguments[1]); 1493 mv.visitFieldInsn(Opcodes.GETFIELD, LOOP_CLAUSES, "clauses", MHARY2); 1494 emitAstoreInsn(clauseDataIndex); 1495 1496 // INIT: 1497 for (int c = 0, state = 0; c < nClauses; ++c) { 1498 MethodType cInitType = loopType.changeReturnType(loopClauseTypes[c].basicTypeClass()); 1499 emitLoopHandleInvoke(invoker, inits, c, args, false, cInitType, loopLocalStateTypes, clauseDataIndex, 1500 firstLoopStateIndex); 1501 if (cInitType.returnType() != void.class) { 1502 emitStoreInsn(BasicType.basicType(cInitType.returnType()), firstLoopStateIndex + state); 1503 ++state; 1504 } 1505 } 1506 1507 // LOOP: 1508 mv.visitLabel(lLoop); 1509 1510 for (int c = 0, state = 0; c < nClauses; ++c) { 1511 lNext = new Label(); 1512 1513 MethodType stepType = loopHandleType.changeReturnType(loopClauseTypes[c].basicTypeClass()); 1514 boolean isVoid = stepType.returnType() == void.class; 1515 1516 // invoke loop step 1517 emitLoopHandleInvoke(invoker, steps, c, args, true, stepType, loopLocalStateTypes, clauseDataIndex, 1518 firstLoopStateIndex); 1519 if (!isVoid) { 1520 emitStoreInsn(BasicType.basicType(stepType.returnType()), firstLoopStateIndex + state); 1521 ++state; 1522 } 1523 1524 // invoke loop predicate 1525 emitLoopHandleInvoke(invoker, preds, c, args, true, predType, loopLocalStateTypes, clauseDataIndex, 1526 firstLoopStateIndex); 1527 mv.visitJumpInsn(Opcodes.IFNE, lNext); 1528 1529 // invoke fini 1530 emitLoopHandleInvoke(invoker, finis, c, args, true, finiType, loopLocalStateTypes, clauseDataIndex, 1531 firstLoopStateIndex); 1532 mv.visitJumpInsn(Opcodes.GOTO, lDone); 1533 1534 // this is the beginning of the next loop clause 1535 mv.visitLabel(lNext); 1536 } 1537 1538 mv.visitJumpInsn(Opcodes.GOTO, lLoop); 1539 1540 // DONE: 1541 mv.visitLabel(lDone); 1542 1543 return result; 1544 } 1545 extendLocalsMap(Class<?>[] types)1546 private int extendLocalsMap(Class<?>[] types) { 1547 int firstSlot = localsMap.length - 1; 1548 localsMap = Arrays.copyOf(localsMap, localsMap.length + types.length); 1549 localClasses = Arrays.copyOf(localClasses, localClasses.length + types.length); 1550 System.arraycopy(types, 0, localClasses, firstSlot, types.length); 1551 int index = localsMap[firstSlot - 1] + 1; 1552 int lastSlots = 0; 1553 for (int i = 0; i < types.length; ++i) { 1554 localsMap[firstSlot + i] = index; 1555 lastSlots = BasicType.basicType(localClasses[firstSlot + i]).basicTypeSlots(); 1556 index += lastSlots; 1557 } 1558 localsMap[localsMap.length - 1] = index - lastSlots; 1559 return firstSlot; 1560 } 1561 emitLoopHandleInvoke(Name holder, int handles, int clause, Name args, boolean pushLocalState, MethodType type, Class<?>[] loopLocalStateTypes, int clauseDataSlot, int firstLoopStateSlot)1562 private void emitLoopHandleInvoke(Name holder, int handles, int clause, Name args, boolean pushLocalState, 1563 MethodType type, Class<?>[] loopLocalStateTypes, int clauseDataSlot, 1564 int firstLoopStateSlot) { 1565 // load handle for clause 1566 emitPushClauseArray(clauseDataSlot, handles); 1567 emitIconstInsn(clause); 1568 mv.visitInsn(Opcodes.AALOAD); 1569 // load loop state (preceding the other arguments) 1570 if (pushLocalState) { 1571 for (int s = 0; s < loopLocalStateTypes.length; ++s) { 1572 emitLoadInsn(BasicType.basicType(loopLocalStateTypes[s]), firstLoopStateSlot + s); 1573 } 1574 } 1575 // load loop args (skip 0: method handle) 1576 emitPushArguments(args, 1); 1577 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.toMethodDescriptorString(), false); 1578 } 1579 emitPushClauseArray(int clauseDataSlot, int which)1580 private void emitPushClauseArray(int clauseDataSlot, int which) { 1581 emitAloadInsn(clauseDataSlot); 1582 emitIconstInsn(which - 1); 1583 mv.visitInsn(Opcodes.AALOAD); 1584 } 1585 emitZero(BasicType type)1586 private void emitZero(BasicType type) { 1587 switch (type) { 1588 case I_TYPE: mv.visitInsn(Opcodes.ICONST_0); break; 1589 case J_TYPE: mv.visitInsn(Opcodes.LCONST_0); break; 1590 case F_TYPE: mv.visitInsn(Opcodes.FCONST_0); break; 1591 case D_TYPE: mv.visitInsn(Opcodes.DCONST_0); break; 1592 case L_TYPE: mv.visitInsn(Opcodes.ACONST_NULL); break; 1593 default: throw new InternalError("unknown type: " + type); 1594 } 1595 } 1596 emitPushArguments(Name args, int start)1597 private void emitPushArguments(Name args, int start) { 1598 MethodType type = args.function.methodType(); 1599 for (int i = start; i < args.arguments.length; i++) { 1600 emitPushArgument(type.parameterType(i), args.arguments[i]); 1601 } 1602 } 1603 emitPushArgument(Name name, int paramIndex)1604 private void emitPushArgument(Name name, int paramIndex) { 1605 Object arg = name.arguments[paramIndex]; 1606 Class<?> ptype = name.function.methodType().parameterType(paramIndex); 1607 emitPushArgument(ptype, arg); 1608 } 1609 emitPushArgument(Class<?> ptype, Object arg)1610 private void emitPushArgument(Class<?> ptype, Object arg) { 1611 BasicType bptype = basicType(ptype); 1612 if (arg instanceof Name) { 1613 Name n = (Name) arg; 1614 emitLoadInsn(n.type, n.index()); 1615 emitImplicitConversion(n.type, ptype, n); 1616 } else if ((arg == null || arg instanceof String) && bptype == L_TYPE) { 1617 emitConst(arg); 1618 } else { 1619 if (Wrapper.isWrapperType(arg.getClass()) && bptype != L_TYPE) { 1620 emitConst(arg); 1621 } else { 1622 mv.visitLdcInsn(constantPlaceholder(arg)); 1623 emitImplicitConversion(L_TYPE, ptype, arg); 1624 } 1625 } 1626 } 1627 1628 /** 1629 * Store the name to its local, if necessary. 1630 */ emitStoreResult(Name name)1631 private void emitStoreResult(Name name) { 1632 if (name != null && name.type != V_TYPE) { 1633 // non-void: actually assign 1634 emitStoreInsn(name.type, name.index()); 1635 } 1636 } 1637 1638 /** 1639 * Emits a return statement from a LF invoker. If required, the result type is cast to the correct return type. 1640 */ emitReturn(Name onStack)1641 private void emitReturn(Name onStack) { 1642 // return statement 1643 Class<?> rclass = invokerType.returnType(); 1644 BasicType rtype = lambdaForm.returnType(); 1645 assert(rtype == basicType(rclass)); // must agree 1646 if (rtype == V_TYPE) { 1647 // void 1648 mv.visitInsn(Opcodes.RETURN); 1649 // it doesn't matter what rclass is; the JVM will discard any value 1650 } else { 1651 LambdaForm.Name rn = lambdaForm.names[lambdaForm.result]; 1652 1653 // put return value on the stack if it is not already there 1654 if (rn != onStack) { 1655 emitLoadInsn(rtype, lambdaForm.result); 1656 } 1657 1658 emitImplicitConversion(rtype, rclass, rn); 1659 1660 // generate actual return statement 1661 emitReturnInsn(rtype); 1662 } 1663 } 1664 1665 /** 1666 * Emit a type conversion bytecode casting from "from" to "to". 1667 */ emitPrimCast(Wrapper from, Wrapper to)1668 private void emitPrimCast(Wrapper from, Wrapper to) { 1669 // Here's how. 1670 // - indicates forbidden 1671 // <-> indicates implicit 1672 // to ----> boolean byte short char int long float double 1673 // from boolean <-> - - - - - - - 1674 // byte - <-> i2s i2c <-> i2l i2f i2d 1675 // short - i2b <-> i2c <-> i2l i2f i2d 1676 // char - i2b i2s <-> <-> i2l i2f i2d 1677 // int - i2b i2s i2c <-> i2l i2f i2d 1678 // long - l2i,i2b l2i,i2s l2i,i2c l2i <-> l2f l2d 1679 // float - f2i,i2b f2i,i2s f2i,i2c f2i f2l <-> f2d 1680 // double - d2i,i2b d2i,i2s d2i,i2c d2i d2l d2f <-> 1681 if (from == to) { 1682 // no cast required, should be dead code anyway 1683 return; 1684 } 1685 if (from.isSubwordOrInt()) { 1686 // cast from {byte,short,char,int} to anything 1687 emitI2X(to); 1688 } else { 1689 // cast from {long,float,double} to anything 1690 if (to.isSubwordOrInt()) { 1691 // cast to {byte,short,char,int} 1692 emitX2I(from); 1693 if (to.bitWidth() < 32) { 1694 // targets other than int require another conversion 1695 emitI2X(to); 1696 } 1697 } else { 1698 // cast to {long,float,double} - this is verbose 1699 boolean error = false; 1700 switch (from) { 1701 case LONG: 1702 switch (to) { 1703 case FLOAT: mv.visitInsn(Opcodes.L2F); break; 1704 case DOUBLE: mv.visitInsn(Opcodes.L2D); break; 1705 default: error = true; break; 1706 } 1707 break; 1708 case FLOAT: 1709 switch (to) { 1710 case LONG : mv.visitInsn(Opcodes.F2L); break; 1711 case DOUBLE: mv.visitInsn(Opcodes.F2D); break; 1712 default: error = true; break; 1713 } 1714 break; 1715 case DOUBLE: 1716 switch (to) { 1717 case LONG : mv.visitInsn(Opcodes.D2L); break; 1718 case FLOAT: mv.visitInsn(Opcodes.D2F); break; 1719 default: error = true; break; 1720 } 1721 break; 1722 default: 1723 error = true; 1724 break; 1725 } 1726 if (error) { 1727 throw new IllegalStateException("unhandled prim cast: " + from + "2" + to); 1728 } 1729 } 1730 } 1731 } 1732 emitI2X(Wrapper type)1733 private void emitI2X(Wrapper type) { 1734 switch (type) { 1735 case BYTE: mv.visitInsn(Opcodes.I2B); break; 1736 case SHORT: mv.visitInsn(Opcodes.I2S); break; 1737 case CHAR: mv.visitInsn(Opcodes.I2C); break; 1738 case INT: /* naught */ break; 1739 case LONG: mv.visitInsn(Opcodes.I2L); break; 1740 case FLOAT: mv.visitInsn(Opcodes.I2F); break; 1741 case DOUBLE: mv.visitInsn(Opcodes.I2D); break; 1742 case BOOLEAN: 1743 // For compatibility with ValueConversions and explicitCastArguments: 1744 mv.visitInsn(Opcodes.ICONST_1); 1745 mv.visitInsn(Opcodes.IAND); 1746 break; 1747 default: throw new InternalError("unknown type: " + type); 1748 } 1749 } 1750 emitX2I(Wrapper type)1751 private void emitX2I(Wrapper type) { 1752 switch (type) { 1753 case LONG: mv.visitInsn(Opcodes.L2I); break; 1754 case FLOAT: mv.visitInsn(Opcodes.F2I); break; 1755 case DOUBLE: mv.visitInsn(Opcodes.D2I); break; 1756 default: throw new InternalError("unknown type: " + type); 1757 } 1758 } 1759 1760 /** 1761 * Generate bytecode for a LambdaForm.vmentry which calls interpretWithArguments. 1762 */ generateLambdaFormInterpreterEntryPoint(MethodType mt)1763 static MemberName generateLambdaFormInterpreterEntryPoint(MethodType mt) { 1764 assert(isValidSignature(basicTypeSignature(mt))); 1765 String name = "interpret_"+basicTypeChar(mt.returnType()); 1766 MethodType type = mt; // includes leading argument 1767 type = type.changeParameterType(0, MethodHandle.class); 1768 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("LFI", name, type); 1769 return g.loadMethod(g.generateLambdaFormInterpreterEntryPointBytes()); 1770 } 1771 generateLambdaFormInterpreterEntryPointBytes()1772 private byte[] generateLambdaFormInterpreterEntryPointBytes() { 1773 classFilePrologue(); 1774 methodPrologue(); 1775 1776 // Suppress this method in backtraces displayed to the user. 1777 mv.visitAnnotation(LF_HIDDEN_SIG, true); 1778 1779 // Don't inline the interpreter entry. 1780 mv.visitAnnotation(DONTINLINE_SIG, true); 1781 1782 // create parameter array 1783 emitIconstInsn(invokerType.parameterCount()); 1784 mv.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object"); 1785 1786 // fill parameter array 1787 for (int i = 0; i < invokerType.parameterCount(); i++) { 1788 Class<?> ptype = invokerType.parameterType(i); 1789 mv.visitInsn(Opcodes.DUP); 1790 emitIconstInsn(i); 1791 emitLoadInsn(basicType(ptype), i); 1792 // box if primitive type 1793 if (ptype.isPrimitive()) { 1794 emitBoxing(Wrapper.forPrimitiveType(ptype)); 1795 } 1796 mv.visitInsn(Opcodes.AASTORE); 1797 } 1798 // invoke 1799 emitAloadInsn(0); 1800 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", "Ljava/lang/invoke/LambdaForm;"); 1801 mv.visitInsn(Opcodes.SWAP); // swap form and array; avoid local variable 1802 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, LF, "interpretWithArguments", "([Ljava/lang/Object;)Ljava/lang/Object;", false); 1803 1804 // maybe unbox 1805 Class<?> rtype = invokerType.returnType(); 1806 if (rtype.isPrimitive() && rtype != void.class) { 1807 emitUnboxing(Wrapper.forPrimitiveType(rtype)); 1808 } 1809 1810 // return statement 1811 emitReturnInsn(basicType(rtype)); 1812 1813 methodEpilogue(); 1814 bogusMethod(invokerType); 1815 1816 final byte[] classFile = cw.toByteArray(); 1817 maybeDump(classFile); 1818 return classFile; 1819 } 1820 1821 /** 1822 * Generate bytecode for a NamedFunction invoker. 1823 */ generateNamedFunctionInvoker(MethodTypeForm typeForm)1824 static MemberName generateNamedFunctionInvoker(MethodTypeForm typeForm) { 1825 MethodType invokerType = NamedFunction.INVOKER_METHOD_TYPE; 1826 String invokerName = "invoke_" + shortenSignature(basicTypeSignature(typeForm.erasedType())); 1827 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("NFI", invokerName, invokerType); 1828 return g.loadMethod(g.generateNamedFunctionInvokerImpl(typeForm)); 1829 } 1830 generateNamedFunctionInvokerImpl(MethodTypeForm typeForm)1831 private byte[] generateNamedFunctionInvokerImpl(MethodTypeForm typeForm) { 1832 MethodType dstType = typeForm.erasedType(); 1833 classFilePrologue(); 1834 methodPrologue(); 1835 1836 // Suppress this method in backtraces displayed to the user. 1837 mv.visitAnnotation(LF_HIDDEN_SIG, true); 1838 1839 // Force inlining of this invoker method. 1840 mv.visitAnnotation(FORCEINLINE_SIG, true); 1841 1842 // Load receiver 1843 emitAloadInsn(0); 1844 1845 // Load arguments from array 1846 for (int i = 0; i < dstType.parameterCount(); i++) { 1847 emitAloadInsn(1); 1848 emitIconstInsn(i); 1849 mv.visitInsn(Opcodes.AALOAD); 1850 1851 // Maybe unbox 1852 Class<?> dptype = dstType.parameterType(i); 1853 if (dptype.isPrimitive()) { 1854 Wrapper dstWrapper = Wrapper.forBasicType(dptype); 1855 Wrapper srcWrapper = dstWrapper.isSubwordOrInt() ? Wrapper.INT : dstWrapper; // narrow subword from int 1856 emitUnboxing(srcWrapper); 1857 emitPrimCast(srcWrapper, dstWrapper); 1858 } 1859 } 1860 1861 // Invoke 1862 String targetDesc = dstType.basicType().toMethodDescriptorString(); 1863 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", targetDesc, false); 1864 1865 // Box primitive types 1866 Class<?> rtype = dstType.returnType(); 1867 if (rtype != void.class && rtype.isPrimitive()) { 1868 Wrapper srcWrapper = Wrapper.forBasicType(rtype); 1869 Wrapper dstWrapper = srcWrapper.isSubwordOrInt() ? Wrapper.INT : srcWrapper; // widen subword to int 1870 // boolean casts not allowed 1871 emitPrimCast(srcWrapper, dstWrapper); 1872 emitBoxing(dstWrapper); 1873 } 1874 1875 // If the return type is void we return a null reference. 1876 if (rtype == void.class) { 1877 mv.visitInsn(Opcodes.ACONST_NULL); 1878 } 1879 emitReturnInsn(L_TYPE); // NOTE: NamedFunction invokers always return a reference value. 1880 1881 methodEpilogue(); 1882 bogusMethod(dstType); 1883 1884 final byte[] classFile = cw.toByteArray(); 1885 maybeDump(classFile); 1886 return classFile; 1887 } 1888 1889 /** 1890 * Emit a bogus method that just loads some string constants. This is to get the constants into the constant pool 1891 * for debugging purposes. 1892 */ bogusMethod(Object os)1893 private void bogusMethod(Object os) { 1894 if (DUMP_CLASS_FILES) { 1895 mv = cw.visitMethod(Opcodes.ACC_STATIC, "dummy", "()V", null, null); 1896 mv.visitLdcInsn(os.toString()); 1897 mv.visitInsn(Opcodes.POP); 1898 mv.visitInsn(Opcodes.RETURN); 1899 mv.visitMaxs(0, 0); 1900 mv.visitEnd(); 1901 } 1902 } 1903 } 1904