1 /*
2 * Copyright (c) 2012, 2020, 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.FieldVisitor;
30 import jdk.internal.org.objectweb.asm.Label;
31 import jdk.internal.org.objectweb.asm.MethodVisitor;
32 import jdk.internal.org.objectweb.asm.Opcodes;
33 import jdk.internal.org.objectweb.asm.Type;
34 import sun.invoke.util.VerifyAccess;
35 import sun.invoke.util.VerifyType;
36 import sun.invoke.util.Wrapper;
37 import sun.reflect.misc.ReflectUtil;
38
39 import java.io.File;
40 import java.io.FileOutputStream;
41 import java.io.IOException;
42 import java.lang.reflect.Modifier;
43 import java.util.ArrayList;
44 import java.util.Arrays;
45 import java.util.HashMap;
46 import java.util.List;
47 import java.util.stream.Stream;
48
49 import static java.lang.invoke.LambdaForm.BasicType;
50 import static java.lang.invoke.LambdaForm.BasicType.*;
51 import static java.lang.invoke.LambdaForm.*;
52 import static java.lang.invoke.MethodHandleNatives.Constants.*;
53 import static java.lang.invoke.MethodHandleStatics.*;
54 import static java.lang.invoke.MethodHandles.Lookup.*;
55
56 /**
57 * Code generation backend for LambdaForm.
58 * <p>
59 * @author John Rose, JSR 292 EG
60 */
61 class InvokerBytecodeGenerator {
62 /** Define class names for convenience. */
63 private static final String MH = "java/lang/invoke/MethodHandle";
64 private static final String MHI = "java/lang/invoke/MethodHandleImpl";
65 private static final String LF = "java/lang/invoke/LambdaForm";
66 private static final String LFN = "java/lang/invoke/LambdaForm$Name";
67 private static final String CLS = "java/lang/Class";
68 private static final String OBJ = "java/lang/Object";
69 private static final String OBJARY = "[Ljava/lang/Object;";
70
71 private static final String LOOP_CLAUSES = MHI + "$LoopClauses";
72 private static final String MHARY2 = "[[L" + MH + ";";
73 private static final String MH_SIG = "L" + MH + ";";
74
75
76 private static final String LF_SIG = "L" + LF + ";";
77 private static final String LFN_SIG = "L" + LFN + ";";
78 private static final String LL_SIG = "(L" + OBJ + ";)L" + OBJ + ";";
79 private static final String LLV_SIG = "(L" + OBJ + ";L" + OBJ + ";)V";
80 private static final String CLASS_PREFIX = LF + "$";
81 private static final String SOURCE_PREFIX = "LambdaForm$";
82
83 /** Name of its super class*/
84 static final String INVOKER_SUPER_NAME = OBJ;
85
86 /** Name of new class */
87 private final String className;
88
89 private final LambdaForm lambdaForm;
90 private final String invokerName;
91 private final MethodType invokerType;
92
93 /** Info about local variables in compiled lambda form */
94 private int[] localsMap; // index
95 private Class<?>[] localClasses; // type
96
97 /** ASM bytecode generation. */
98 private ClassWriter cw;
99 private MethodVisitor mv;
100 private final List<ClassData> classData = new ArrayList<>();
101
102 /** Single element internal class name lookup cache. */
103 private Class<?> lastClass;
104 private String lastInternalName;
105
106 private static final MemberName.Factory MEMBERNAME_FACTORY = MemberName.getFactory();
107 private static final Class<?> HOST_CLASS = LambdaForm.class;
108 private static final MethodHandles.Lookup LOOKUP = lookup();
109
110 private static MethodHandles.Lookup lookup() {
111 try {
112 return MethodHandles.privateLookupIn(HOST_CLASS, IMPL_LOOKUP);
113 } catch (IllegalAccessException e) {
114 throw newInternalError(e);
115 }
116 }
117
118 /** Main constructor; other constructors delegate to this one. */
119 private InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize,
120 String className, String invokerName, MethodType invokerType) {
121 int p = invokerName.indexOf('.');
122 if (p > -1) {
123 className = invokerName.substring(0, p);
124 invokerName = invokerName.substring(p + 1);
125 }
126 if (DUMP_CLASS_FILES) {
127 className = makeDumpableClassName(className);
128 }
129 this.className = className;
130 this.lambdaForm = lambdaForm;
131 this.invokerName = invokerName;
132 this.invokerType = invokerType;
133 this.localsMap = new int[localsMapSize+1]; // last entry of localsMap is count of allocated local slots
134 this.localClasses = new Class<?>[localsMapSize+1];
135 }
136
137 /** For generating LambdaForm interpreter entry points. */
138 private InvokerBytecodeGenerator(String className, String invokerName, MethodType invokerType) {
139 this(null, invokerType.parameterCount(),
140 className, invokerName, invokerType);
141 MethodType mt = invokerType.erase();
142 // Create an array to map name indexes to locals indexes.
143 localsMap[0] = 0; // localsMap has at least one element
144 for (int i = 1, index = 0; i < localsMap.length; i++) {
145 Wrapper w = Wrapper.forBasicType(mt.parameterType(i - 1));
146 index += w.stackSlots();
147 localsMap[i] = index;
148 }
149 }
150
151 /** For generating customized code for a single LambdaForm. */
152 private InvokerBytecodeGenerator(String className, LambdaForm form, MethodType invokerType) {
153 this(className, form.lambdaName(), form, invokerType);
154 }
155
156 /** For generating customized code for a single LambdaForm. */
157 InvokerBytecodeGenerator(String className, String invokerName,
158 LambdaForm form, MethodType invokerType) {
159 this(form, form.names.length,
160 className, invokerName, invokerType);
161 // Create an array to map name indexes to locals indexes.
162 Name[] names = form.names;
163 for (int i = 0, index = 0; i < localsMap.length; i++) {
164 localsMap[i] = index;
165 if (i < names.length) {
166 BasicType type = names[i].type();
167 index += type.basicTypeSlots();
168 }
169 }
170 }
171
172 /** instance counters for dumped classes */
173 private static final HashMap<String,Integer> DUMP_CLASS_FILES_COUNTERS;
174 /** debugging flag for saving generated class files */
175 private static final File DUMP_CLASS_FILES_DIR;
176
177 static {
178 if (DUMP_CLASS_FILES) {
179 DUMP_CLASS_FILES_COUNTERS = new HashMap<>();
180 try {
181 File dumpDir = new File("DUMP_CLASS_FILES");
182 if (!dumpDir.exists()) {
183 dumpDir.mkdirs();
184 }
185 DUMP_CLASS_FILES_DIR = dumpDir;
186 System.out.println("Dumping class files to "+DUMP_CLASS_FILES_DIR+"/...");
187 } catch (Exception e) {
188 throw newInternalError(e);
189 }
190 } else {
191 DUMP_CLASS_FILES_COUNTERS = null;
192 DUMP_CLASS_FILES_DIR = null;
193 }
194 }
195
196 private void maybeDump(final byte[] classFile) {
197 if (DUMP_CLASS_FILES) {
198 maybeDump(CLASS_PREFIX + className, classFile);
199 }
200 }
201
202 // Also used from BoundMethodHandle
203 static void maybeDump(final String className, final byte[] classFile) {
204 if (DUMP_CLASS_FILES) {
205 java.security.AccessController.doPrivileged(
206 new java.security.PrivilegedAction<>() {
207 public Void run() {
208 try {
209 String dumpName = className.replace('.','/');
210 File dumpFile = new File(DUMP_CLASS_FILES_DIR, dumpName+".class");
211 System.out.println("dump: " + dumpFile);
212 dumpFile.getParentFile().mkdirs();
213 FileOutputStream file = new FileOutputStream(dumpFile);
214 file.write(classFile);
215 file.close();
216 return null;
217 } catch (IOException ex) {
218 throw newInternalError(ex);
219 }
220 }
221 });
222 }
223 }
224
225 private static String makeDumpableClassName(String className) {
226 Integer ctr;
227 synchronized (DUMP_CLASS_FILES_COUNTERS) {
228 ctr = DUMP_CLASS_FILES_COUNTERS.get(className);
229 if (ctr == null) ctr = 0;
230 DUMP_CLASS_FILES_COUNTERS.put(className, ctr+1);
231 }
232 String sfx = ctr.toString();
233 while (sfx.length() < 3)
234 sfx = "0"+sfx;
235 className += sfx;
236 return className;
237 }
238
239 static class ClassData {
240 final String name;
241 final String desc;
242 final Object value;
243
244 ClassData(String name, String desc, Object value) {
245 this.name = name;
246 this.desc = desc;
247 this.value = value;
248 }
249
250 public String name() { return name; }
251 public String toString() {
252 return name + ",value="+value;
253 }
254 }
255
256 String classData(Object arg) {
257 String desc;
258 if (arg instanceof Class) {
259 desc = "Ljava/lang/Class;";
260 } else if (arg instanceof MethodHandle) {
261 desc = MH_SIG;
262 } else if (arg instanceof LambdaForm) {
263 desc = LF_SIG;
264 } else {
265 desc = "Ljava/lang/Object;";
266 }
267
268 Class<?> c = arg.getClass();
269 while (c.isArray()) {
270 c = c.getComponentType();
271 }
272 // unique static variable name
273 String name = "_DATA_" + c.getSimpleName() + "_" + classData.size();
274 ClassData cd = new ClassData(name, desc, arg);
275 classData.add(cd);
276 return cd.name();
277 }
278
279 List<Object> classDataValues() {
280 Object[] data = new Object[classData.size()];
281 for (int i = 0; i < classData.size(); i++) {
282 data[i] = classData.get(i).value;
283 }
284 return List.of(data);
285 }
286
287 private static String debugString(Object arg) {
288 if (arg instanceof MethodHandle) {
289 MethodHandle mh = (MethodHandle) arg;
290 MemberName member = mh.internalMemberName();
291 if (member != null)
292 return member.toString();
293 return mh.debugString();
294 }
295 return arg.toString();
296 }
297
298 /**
299 * Extract the number of constant pool entries from a given class file.
300 *
301 * @param classFile the bytes of the class file in question.
302 * @return the number of entries in the constant pool.
303 */
304 private static int getConstantPoolSize(byte[] classFile) {
305 // The first few bytes:
306 // u4 magic;
307 // u2 minor_version;
308 // u2 major_version;
309 // u2 constant_pool_count;
310 return ((classFile[8] & 0xFF) << 8) | (classFile[9] & 0xFF);
311 }
312
313 /**
314 * Extract the MemberName of a newly-defined method.
315 */
316 private MemberName loadMethod(byte[] classFile) {
317 Class<?> invokerClass = LOOKUP.makeHiddenClassDefiner(className(), classFile)
318 .defineClass(true, classDataValues());
319 return resolveInvokerMember(invokerClass, invokerName, invokerType);
320 }
321
322 private static MemberName resolveInvokerMember(Class<?> invokerClass, String name, MethodType type) {
323 MemberName member = new MemberName(invokerClass, name, type, REF_invokeStatic);
324 try {
325 member = MEMBERNAME_FACTORY.resolveOrFail(REF_invokeStatic, member, HOST_CLASS, ReflectiveOperationException.class);
326 } catch (ReflectiveOperationException e) {
327 throw newInternalError(e);
328 }
329 return member;
330 }
331
332 /**
333 * Set up class file generation.
334 */
335 private ClassWriter classFilePrologue() {
336 final int NOT_ACC_PUBLIC = 0; // not ACC_PUBLIC
337 ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
338 setClassWriter(cw);
339 cw.visit(Opcodes.V1_8, NOT_ACC_PUBLIC + Opcodes.ACC_FINAL + Opcodes.ACC_SUPER,
340 CLASS_PREFIX + className, null, INVOKER_SUPER_NAME, null);
341 cw.visitSource(SOURCE_PREFIX + className, null);
342 return cw;
343 }
344
345 private void methodPrologue() {
346 String invokerDesc = invokerType.toMethodDescriptorString();
347 mv = cw.visitMethod(Opcodes.ACC_STATIC, invokerName, invokerDesc, null, null);
348 }
349
350 /**
351 * Tear down class file generation.
352 */
353 private void methodEpilogue() {
354 mv.visitMaxs(0, 0);
355 mv.visitEnd();
356 }
357
358 private String className() {
359 return CLASS_PREFIX + className;
360 }
361
362 private void clinit() {
363 clinit(cw, className(), classData);
364 }
365
366 /*
367 * <clinit> to initialize the static final fields with the live class data
368 * LambdaForms can't use condy due to bootstrapping issue.
369 */
370 static void clinit(ClassWriter cw, String className, List<ClassData> classData) {
371 if (classData.isEmpty())
372 return;
373
374 for (ClassData p : classData) {
375 // add the static field
376 FieldVisitor fv = cw.visitField(Opcodes.ACC_STATIC|Opcodes.ACC_FINAL, p.name, p.desc, null, null);
377 fv.visitEnd();
378 }
379
380 MethodVisitor mv = cw.visitMethod(Opcodes.ACC_STATIC, "<clinit>", "()V", null, null);
381 mv.visitCode();
382 mv.visitLdcInsn(Type.getType("L" + className + ";"));
383 mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/invoke/MethodHandleNatives",
384 "classData", "(Ljava/lang/Class;)Ljava/lang/Object;", false);
385 // we should optimize one single element case that does not need to create a List
386 mv.visitTypeInsn(Opcodes.CHECKCAST, "java/util/List");
387 mv.visitVarInsn(Opcodes.ASTORE, 0);
388 int index = 0;
389 for (ClassData p : classData) {
390 // initialize the static field
391 mv.visitVarInsn(Opcodes.ALOAD, 0);
392 emitIconstInsn(mv, index++);
393 mv.visitMethodInsn(Opcodes.INVOKEINTERFACE, "java/util/List",
394 "get", "(I)Ljava/lang/Object;", true);
395 mv.visitTypeInsn(Opcodes.CHECKCAST, p.desc.substring(1, p.desc.length()-1));
396 mv.visitFieldInsn(Opcodes.PUTSTATIC, className, p.name, p.desc);
397 }
398 mv.visitInsn(Opcodes.RETURN);
399 mv.visitMaxs(2, 1);
400 mv.visitEnd();
401 }
402
403 /*
404 * Low-level emit helpers.
405 */
406 private void emitConst(Object con) {
407 if (con == null) {
408 mv.visitInsn(Opcodes.ACONST_NULL);
409 return;
410 }
411 if (con instanceof Integer) {
412 emitIconstInsn((int) con);
413 return;
414 }
415 if (con instanceof Byte) {
416 emitIconstInsn((byte)con);
417 return;
418 }
419 if (con instanceof Short) {
420 emitIconstInsn((short)con);
421 return;
422 }
423 if (con instanceof Character) {
424 emitIconstInsn((char)con);
425 return;
426 }
427 if (con instanceof Long) {
428 long x = (long) con;
429 short sx = (short)x;
430 if (x == sx) {
431 if (sx >= 0 && sx <= 1) {
432 mv.visitInsn(Opcodes.LCONST_0 + (int) sx);
433 } else {
434 emitIconstInsn((int) x);
435 mv.visitInsn(Opcodes.I2L);
436 }
437 return;
438 }
439 }
440 if (con instanceof Float) {
441 float x = (float) con;
442 short sx = (short)x;
443 if (x == sx) {
444 if (sx >= 0 && sx <= 2) {
445 mv.visitInsn(Opcodes.FCONST_0 + (int) sx);
446 } else {
447 emitIconstInsn((int) x);
448 mv.visitInsn(Opcodes.I2F);
449 }
450 return;
451 }
452 }
453 if (con instanceof Double) {
454 double x = (double) con;
455 short sx = (short)x;
456 if (x == sx) {
457 if (sx >= 0 && sx <= 1) {
458 mv.visitInsn(Opcodes.DCONST_0 + (int) sx);
459 } else {
460 emitIconstInsn((int) x);
461 mv.visitInsn(Opcodes.I2D);
462 }
463 return;
464 }
465 }
466 if (con instanceof Boolean) {
467 emitIconstInsn((boolean) con ? 1 : 0);
468 return;
469 }
470 // fall through:
471 mv.visitLdcInsn(con);
472 }
473
474 private void emitIconstInsn(final int cst) {
475 emitIconstInsn(mv, cst);
476 }
477
478 private static void emitIconstInsn(MethodVisitor mv, int cst) {
479 if (cst >= -1 && cst <= 5) {
480 mv.visitInsn(Opcodes.ICONST_0 + cst);
481 } else if (cst >= Byte.MIN_VALUE && cst <= Byte.MAX_VALUE) {
482 mv.visitIntInsn(Opcodes.BIPUSH, cst);
483 } else if (cst >= Short.MIN_VALUE && cst <= Short.MAX_VALUE) {
484 mv.visitIntInsn(Opcodes.SIPUSH, cst);
485 } else {
486 mv.visitLdcInsn(cst);
487 }
488 }
489
490 /*
491 * NOTE: These load/store methods use the localsMap to find the correct index!
492 */
493 private void emitLoadInsn(BasicType type, int index) {
494 int opcode = loadInsnOpcode(type);
495 mv.visitVarInsn(opcode, localsMap[index]);
496 }
497
498 private int loadInsnOpcode(BasicType type) throws InternalError {
499 switch (type) {
500 case I_TYPE: return Opcodes.ILOAD;
501 case J_TYPE: return Opcodes.LLOAD;
502 case F_TYPE: return Opcodes.FLOAD;
503 case D_TYPE: return Opcodes.DLOAD;
504 case L_TYPE: return Opcodes.ALOAD;
505 default:
506 throw new InternalError("unknown type: " + type);
507 }
508 }
509 private void emitAloadInsn(int index) {
510 emitLoadInsn(L_TYPE, index);
511 }
512
513 private void emitStoreInsn(BasicType type, int index) {
514 int opcode = storeInsnOpcode(type);
515 mv.visitVarInsn(opcode, localsMap[index]);
516 }
517
518 private int storeInsnOpcode(BasicType type) throws InternalError {
519 switch (type) {
520 case I_TYPE: return Opcodes.ISTORE;
521 case J_TYPE: return Opcodes.LSTORE;
522 case F_TYPE: return Opcodes.FSTORE;
523 case D_TYPE: return Opcodes.DSTORE;
524 case L_TYPE: return Opcodes.ASTORE;
525 default:
526 throw new InternalError("unknown type: " + type);
527 }
528 }
529 private void emitAstoreInsn(int index) {
530 emitStoreInsn(L_TYPE, index);
531 }
532
533 private byte arrayTypeCode(Wrapper elementType) {
534 switch (elementType) {
535 case BOOLEAN: return Opcodes.T_BOOLEAN;
536 case BYTE: return Opcodes.T_BYTE;
537 case CHAR: return Opcodes.T_CHAR;
538 case SHORT: return Opcodes.T_SHORT;
539 case INT: return Opcodes.T_INT;
540 case LONG: return Opcodes.T_LONG;
541 case FLOAT: return Opcodes.T_FLOAT;
542 case DOUBLE: return Opcodes.T_DOUBLE;
543 case OBJECT: return 0; // in place of Opcodes.T_OBJECT
544 default: throw new InternalError();
545 }
546 }
547
548 private int arrayInsnOpcode(byte tcode, int aaop) throws InternalError {
549 assert(aaop == Opcodes.AASTORE || aaop == Opcodes.AALOAD);
550 int xas;
551 switch (tcode) {
552 case Opcodes.T_BOOLEAN: xas = Opcodes.BASTORE; break;
553 case Opcodes.T_BYTE: xas = Opcodes.BASTORE; break;
554 case Opcodes.T_CHAR: xas = Opcodes.CASTORE; break;
555 case Opcodes.T_SHORT: xas = Opcodes.SASTORE; break;
556 case Opcodes.T_INT: xas = Opcodes.IASTORE; break;
557 case Opcodes.T_LONG: xas = Opcodes.LASTORE; break;
558 case Opcodes.T_FLOAT: xas = Opcodes.FASTORE; break;
559 case Opcodes.T_DOUBLE: xas = Opcodes.DASTORE; break;
560 case 0: xas = Opcodes.AASTORE; break;
561 default: throw new InternalError();
562 }
563 return xas - Opcodes.AASTORE + aaop;
564 }
565
566 /**
567 * Emit a boxing call.
568 *
569 * @param wrapper primitive type class to box.
570 */
571 private void emitBoxing(Wrapper wrapper) {
572 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
573 String name = "valueOf";
574 String desc = "(" + wrapper.basicTypeChar() + ")L" + owner + ";";
575 mv.visitMethodInsn(Opcodes.INVOKESTATIC, owner, name, desc, false);
576 }
577
578 /**
579 * Emit an unboxing call (plus preceding checkcast).
580 *
581 * @param wrapper wrapper type class to unbox.
582 */
583 private void emitUnboxing(Wrapper wrapper) {
584 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
585 String name = wrapper.primitiveSimpleName() + "Value";
586 String desc = "()" + wrapper.basicTypeChar();
587 emitReferenceCast(wrapper.wrapperType(), null);
588 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, owner, name, desc, false);
589 }
590
591 /**
592 * Emit an implicit conversion for an argument which must be of the given pclass.
593 * This is usually a no-op, except when pclass is a subword type or a reference other than Object or an interface.
594 *
595 * @param ptype type of value present on stack
596 * @param pclass type of value required on stack
597 * @param arg compile-time representation of value on stack (Node, constant) or null if none
598 */
599 private void emitImplicitConversion(BasicType ptype, Class<?> pclass, Object arg) {
600 assert(basicType(pclass) == ptype); // boxing/unboxing handled by caller
601 if (pclass == ptype.basicTypeClass() && ptype != L_TYPE)
602 return; // nothing to do
603 switch (ptype) {
604 case L_TYPE:
605 if (VerifyType.isNullConversion(Object.class, pclass, false)) {
606 if (PROFILE_LEVEL > 0)
607 emitReferenceCast(Object.class, arg);
608 return;
609 }
610 emitReferenceCast(pclass, arg);
611 return;
612 case I_TYPE:
613 if (!VerifyType.isNullConversion(int.class, pclass, false))
614 emitPrimCast(ptype.basicTypeWrapper(), Wrapper.forPrimitiveType(pclass));
615 return;
616 }
617 throw newInternalError("bad implicit conversion: tc="+ptype+": "+pclass);
618 }
619
620 /** Update localClasses type map. Return true if the information is already present. */
621 private boolean assertStaticType(Class<?> cls, Name n) {
622 int local = n.index();
623 Class<?> aclass = localClasses[local];
624 if (aclass != null && (aclass == cls || cls.isAssignableFrom(aclass))) {
625 return true; // type info is already present
626 } else if (aclass == null || aclass.isAssignableFrom(cls)) {
627 localClasses[local] = cls; // type info can be improved
628 }
629 return false;
630 }
631
632 private void emitReferenceCast(Class<?> cls, Object arg) {
633 Name writeBack = null; // local to write back result
634 if (arg instanceof Name) {
635 Name n = (Name) arg;
636 if (lambdaForm.useCount(n) > 1) {
637 // This guy gets used more than once.
638 writeBack = n;
639 if (assertStaticType(cls, n)) {
640 return; // this cast was already performed
641 }
642 }
643 }
644 if (isStaticallyNameable(cls)) {
645 String sig = getInternalName(cls);
646 mv.visitTypeInsn(Opcodes.CHECKCAST, sig);
647 } else {
648 mv.visitFieldInsn(Opcodes.GETSTATIC, className(), classData(cls), "Ljava/lang/Class;");
649 mv.visitInsn(Opcodes.SWAP);
650 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, CLS, "cast", LL_SIG, false);
651 if (Object[].class.isAssignableFrom(cls))
652 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJARY);
653 else if (PROFILE_LEVEL > 0)
654 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJ);
655 }
656 if (writeBack != null) {
657 mv.visitInsn(Opcodes.DUP);
658 emitAstoreInsn(writeBack.index());
659 }
660 }
661
662 /**
663 * Emits an actual return instruction conforming to the given return type.
664 */
665 private void emitReturnInsn(BasicType type) {
666 int opcode;
667 switch (type) {
668 case I_TYPE: opcode = Opcodes.IRETURN; break;
669 case J_TYPE: opcode = Opcodes.LRETURN; break;
670 case F_TYPE: opcode = Opcodes.FRETURN; break;
671 case D_TYPE: opcode = Opcodes.DRETURN; break;
672 case L_TYPE: opcode = Opcodes.ARETURN; break;
673 case V_TYPE: opcode = Opcodes.RETURN; break;
674 default:
675 throw new InternalError("unknown return type: " + type);
676 }
677 mv.visitInsn(opcode);
678 }
679
680 private String getInternalName(Class<?> c) {
681 if (c == Object.class) return OBJ;
682 else if (c == Object[].class) return OBJARY;
683 else if (c == Class.class) return CLS;
684 else if (c == MethodHandle.class) return MH;
685 assert(VerifyAccess.isTypeVisible(c, Object.class)) : c.getName();
686
687 if (c == lastClass) {
688 return lastInternalName;
689 }
690 lastClass = c;
691 return lastInternalName = c.getName().replace('.', '/');
692 }
693
694 private static MemberName resolveFrom(String name, MethodType type, Class<?> holder) {
695 MemberName member = new MemberName(holder, name, type, REF_invokeStatic);
696 MemberName resolvedMember = MemberName.getFactory().resolveOrNull(REF_invokeStatic, member, holder);
697 if (TRACE_RESOLVE || CDS_TRACE_RESOLVE) {
698 String outLine = "[LF_RESOLVE] " + holder.getName() + " " + name + " " +
699 shortenSignature(basicTypeSignature(type)) + (resolvedMember != null ? " (success)" : " (fail)");
700 if (TRACE_RESOLVE) {
701 System.out.println(outLine);
702 }
703 if (CDS_TRACE_RESOLVE) {
704 InvokerBytecodeGeneratorHelper.cdsTraceResolve(outLine);
705 }
706 }
707 return resolvedMember;
708 }
709
710 private static MemberName lookupPregenerated(LambdaForm form, MethodType invokerType) {
711 if (form.customized != null) {
712 // No pre-generated version for customized LF
713 return null;
714 }
715 String name = form.kind.methodName;
716 switch (form.kind) {
717 case BOUND_REINVOKER: {
718 name = name + "_" + BoundMethodHandle.speciesDataFor(form).key();
719 return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class);
720 }
721 case DELEGATE: return resolveFrom(name, invokerType, DelegatingMethodHandle.Holder.class);
722 case ZERO: // fall-through
723 case IDENTITY: {
724 name = name + "_" + form.returnType().basicTypeChar();
725 return resolveFrom(name, invokerType, LambdaForm.Holder.class);
726 }
727 case EXACT_INVOKER: // fall-through
728 case EXACT_LINKER: // fall-through
729 case LINK_TO_CALL_SITE: // fall-through
730 case LINK_TO_TARGET_METHOD: // fall-through
731 case GENERIC_INVOKER: // fall-through
732 case GENERIC_LINKER: return resolveFrom(name, invokerType.basicType(), Invokers.Holder.class);
733 case GET_REFERENCE: // fall-through
734 case GET_BOOLEAN: // fall-through
735 case GET_BYTE: // fall-through
736 case GET_CHAR: // fall-through
737 case GET_SHORT: // fall-through
738 case GET_INT: // fall-through
739 case GET_LONG: // fall-through
740 case GET_FLOAT: // fall-through
741 case GET_DOUBLE: // fall-through
742 case PUT_REFERENCE: // fall-through
743 case PUT_BOOLEAN: // fall-through
744 case PUT_BYTE: // fall-through
745 case PUT_CHAR: // fall-through
746 case PUT_SHORT: // fall-through
747 case PUT_INT: // fall-through
748 case PUT_LONG: // fall-through
749 case PUT_FLOAT: // fall-through
750 case PUT_DOUBLE: // fall-through
751 case DIRECT_NEW_INVOKE_SPECIAL: // fall-through
752 case DIRECT_INVOKE_INTERFACE: // fall-through
753 case DIRECT_INVOKE_SPECIAL: // fall-through
754 case DIRECT_INVOKE_SPECIAL_IFC: // fall-through
755 case DIRECT_INVOKE_STATIC: // fall-through
756 case DIRECT_INVOKE_STATIC_INIT: // fall-through
757 case DIRECT_INVOKE_VIRTUAL: return resolveFrom(name, invokerType, DirectMethodHandle.Holder.class);
758 }
759 return null;
760 }
761
762 /**
763 * Generate customized bytecode for a given LambdaForm.
764 */
765 static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) {
766 MemberName pregenerated = lookupPregenerated(form, invokerType);
767 if (pregenerated != null) return pregenerated; // pre-generated bytecode
768
769 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("MH", form, invokerType);
770 return g.loadMethod(g.generateCustomizedCodeBytes());
771 }
772
773 /** Generates code to check that actual receiver and LambdaForm matches */
774 private boolean checkActualReceiver() {
775 // Expects MethodHandle on the stack and actual receiver MethodHandle in slot #0
776 mv.visitInsn(Opcodes.DUP);
777 mv.visitVarInsn(Opcodes.ALOAD, localsMap[0]);
778 mv.visitMethodInsn(Opcodes.INVOKESTATIC, MHI, "assertSame", LLV_SIG, false);
779 return true;
780 }
781
782 static String className(String cn) {
783 assert checkClassName(cn): "Class not found: " + cn;
784 return cn;
785 }
786
787 static boolean checkClassName(String cn) {
788 Type tp = Type.getType(cn);
789 // additional sanity so only valid "L;" descriptors work
790 if (tp.getSort() != Type.OBJECT) {
791 return false;
792 }
793 try {
794 Class<?> c = Class.forName(tp.getClassName(), false, null);
795 return true;
796 } catch (ClassNotFoundException e) {
797 return false;
798 }
799 }
800
801 static final String DONTINLINE_SIG = className("Ljdk/internal/vm/annotation/DontInline;");
802 static final String FORCEINLINE_SIG = className("Ljdk/internal/vm/annotation/ForceInline;");
803 static final String HIDDEN_SIG = className("Ljdk/internal/vm/annotation/Hidden;");
804 static final String INJECTEDPROFILE_SIG = className("Ljava/lang/invoke/InjectedProfile;");
805 static final String LF_COMPILED_SIG = className("Ljava/lang/invoke/LambdaForm$Compiled;");
806
807 /**
808 * Generate an invoker method for the passed {@link LambdaForm}.
809 */
810 private byte[] generateCustomizedCodeBytes() {
811 classFilePrologue();
812 addMethod();
813 clinit();
814 bogusMethod(lambdaForm);
815
816 final byte[] classFile = toByteArray();
817 maybeDump(classFile);
818 return classFile;
819 }
820
821 void setClassWriter(ClassWriter cw) {
822 this.cw = cw;
823 }
824
825 void addMethod() {
826 methodPrologue();
827
828 // Suppress this method in backtraces displayed to the user.
829 mv.visitAnnotation(HIDDEN_SIG, true);
830
831 // Mark this method as a compiled LambdaForm
832 mv.visitAnnotation(LF_COMPILED_SIG, true);
833
834 if (lambdaForm.forceInline) {
835 // Force inlining of this invoker method.
836 mv.visitAnnotation(FORCEINLINE_SIG, true);
837 } else {
838 mv.visitAnnotation(DONTINLINE_SIG, true);
839 }
840
841 classData(lambdaForm); // keep LambdaForm instance & its compiled form lifetime tightly coupled.
842
843 if (lambdaForm.customized != null) {
844 // Since LambdaForm is customized for a particular MethodHandle, it's safe to substitute
845 // receiver MethodHandle (at slot #0) with an embedded constant and use it instead.
846 // It enables more efficient code generation in some situations, since embedded constants
847 // are compile-time constants for JIT compiler.
848 mv.visitFieldInsn(Opcodes.GETSTATIC, className(), classData(lambdaForm.customized), MH_SIG);
849 mv.visitTypeInsn(Opcodes.CHECKCAST, MH);
850 assert(checkActualReceiver()); // expects MethodHandle on top of the stack
851 mv.visitVarInsn(Opcodes.ASTORE, localsMap[0]);
852 }
853
854 // iterate over the form's names, generating bytecode instructions for each
855 // start iterating at the first name following the arguments
856 Name onStack = null;
857 for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) {
858 Name name = lambdaForm.names[i];
859
860 emitStoreResult(onStack);
861 onStack = name; // unless otherwise modified below
862 MethodHandleImpl.Intrinsic intr = name.function.intrinsicName();
863 switch (intr) {
864 case SELECT_ALTERNATIVE:
865 assert lambdaForm.isSelectAlternative(i);
866 if (PROFILE_GWT) {
867 assert(name.arguments[0] instanceof Name &&
868 ((Name)name.arguments[0]).refersTo(MethodHandleImpl.class, "profileBoolean"));
869 mv.visitAnnotation(INJECTEDPROFILE_SIG, true);
870 }
871 onStack = emitSelectAlternative(name, lambdaForm.names[i+1]);
872 i++; // skip MH.invokeBasic of the selectAlternative result
873 continue;
874 case GUARD_WITH_CATCH:
875 assert lambdaForm.isGuardWithCatch(i);
876 onStack = emitGuardWithCatch(i);
877 i += 2; // jump to the end of GWC idiom
878 continue;
879 case TRY_FINALLY:
880 assert lambdaForm.isTryFinally(i);
881 onStack = emitTryFinally(i);
882 i += 2; // jump to the end of the TF idiom
883 continue;
884 case LOOP:
885 assert lambdaForm.isLoop(i);
886 onStack = emitLoop(i);
887 i += 2; // jump to the end of the LOOP idiom
888 continue;
889 case NEW_ARRAY:
890 Class<?> rtype = name.function.methodType().returnType();
891 if (isStaticallyNameable(rtype)) {
892 emitNewArray(name);
893 continue;
894 }
895 break;
896 case ARRAY_LOAD:
897 emitArrayLoad(name);
898 continue;
899 case ARRAY_STORE:
900 emitArrayStore(name);
901 continue;
902 case ARRAY_LENGTH:
903 emitArrayLength(name);
904 continue;
905 case IDENTITY:
906 assert(name.arguments.length == 1);
907 emitPushArguments(name, 0);
908 continue;
909 case ZERO:
910 assert(name.arguments.length == 0);
911 emitConst(name.type.basicTypeWrapper().zero());
912 continue;
913 case NONE:
914 // no intrinsic associated
915 break;
916 default:
917 throw newInternalError("Unknown intrinsic: "+intr);
918 }
919
920 MemberName member = name.function.member();
921 if (isStaticallyInvocable(member)) {
922 emitStaticInvoke(member, name);
923 } else {
924 emitInvoke(name);
925 }
926 }
927
928 // return statement
929 emitReturn(onStack);
930
931 methodEpilogue();
932 }
933
934 /*
935 * @throws BytecodeGenerationException if something goes wrong when
936 * generating the byte code
937 */
938 private byte[] toByteArray() {
939 try {
940 return cw.toByteArray();
941 } catch (RuntimeException e) {
942 throw new BytecodeGenerationException(e);
943 }
944 }
945
946 @SuppressWarnings("serial")
947 static final class BytecodeGenerationException extends RuntimeException {
948 BytecodeGenerationException(Exception cause) {
949 super(cause);
950 }
951 }
952
953 void emitArrayLoad(Name name) { emitArrayOp(name, Opcodes.AALOAD); }
954 void emitArrayStore(Name name) { emitArrayOp(name, Opcodes.AASTORE); }
955 void emitArrayLength(Name name) { emitArrayOp(name, Opcodes.ARRAYLENGTH); }
956
957 void emitArrayOp(Name name, int arrayOpcode) {
958 assert arrayOpcode == Opcodes.AALOAD || arrayOpcode == Opcodes.AASTORE || arrayOpcode == Opcodes.ARRAYLENGTH;
959 Class<?> elementType = name.function.methodType().parameterType(0).getComponentType();
960 assert elementType != null;
961 emitPushArguments(name, 0);
962 if (arrayOpcode != Opcodes.ARRAYLENGTH && elementType.isPrimitive()) {
963 Wrapper w = Wrapper.forPrimitiveType(elementType);
964 arrayOpcode = arrayInsnOpcode(arrayTypeCode(w), arrayOpcode);
965 }
966 mv.visitInsn(arrayOpcode);
967 }
968
969 /**
970 * Emit an invoke for the given name.
971 */
972 void emitInvoke(Name name) {
973 assert(!name.isLinkerMethodInvoke()); // should use the static path for these
974 if (true) {
975 // push receiver
976 MethodHandle target = name.function.resolvedHandle();
977 assert(target != null) : name.exprString();
978 mv.visitFieldInsn(Opcodes.GETSTATIC, className(), classData(target), MH_SIG);
979 emitReferenceCast(MethodHandle.class, target);
980 } else {
981 // load receiver
982 emitAloadInsn(0);
983 emitReferenceCast(MethodHandle.class, null);
984 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", LF_SIG);
985 mv.visitFieldInsn(Opcodes.GETFIELD, LF, "names", LFN_SIG);
986 // TODO more to come
987 }
988
989 // push arguments
990 emitPushArguments(name, 0);
991
992 // invocation
993 MethodType type = name.function.methodType();
994 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
995 }
996
997 private static Class<?>[] STATICALLY_INVOCABLE_PACKAGES = {
998 // Sample classes from each package we are willing to bind to statically:
999 java.lang.Object.class,
1000 java.util.Arrays.class,
1001 jdk.internal.misc.Unsafe.class
1002 //MethodHandle.class already covered
1003 };
1004
1005 static boolean isStaticallyInvocable(NamedFunction ... functions) {
1006 for (NamedFunction nf : functions) {
1007 if (!isStaticallyInvocable(nf.member())) {
1008 return false;
1009 }
1010 }
1011 return true;
1012 }
1013
1014 static boolean isStaticallyInvocable(Name name) {
1015 return isStaticallyInvocable(name.function.member());
1016 }
1017
1018 static boolean isStaticallyInvocable(MemberName member) {
1019 if (member == null) return false;
1020 if (member.isConstructor()) return false;
1021 Class<?> cls = member.getDeclaringClass();
1022 // Fast-path non-private members declared by MethodHandles, which is a common
1023 // case
1024 if (MethodHandle.class.isAssignableFrom(cls) && !member.isPrivate()) {
1025 assert(isStaticallyInvocableType(member.getMethodOrFieldType()));
1026 return true;
1027 }
1028 if (cls.isArray() || cls.isPrimitive())
1029 return false; // FIXME
1030 if (cls.isAnonymousClass() || cls.isLocalClass())
1031 return false; // inner class of some sort
1032 if (cls.getClassLoader() != MethodHandle.class.getClassLoader())
1033 return false; // not on BCP
1034 if (cls.isHidden())
1035 return false;
1036 if (ReflectUtil.isVMAnonymousClass(cls)) // FIXME: Unsafe::defineAnonymousClass to be removed
1037 return false;
1038 if (!isStaticallyInvocableType(member.getMethodOrFieldType()))
1039 return false;
1040 if (!member.isPrivate() && VerifyAccess.isSamePackage(MethodHandle.class, cls))
1041 return true; // in java.lang.invoke package
1042 if (member.isPublic() && isStaticallyNameable(cls))
1043 return true;
1044 return false;
1045 }
1046
1047 private static boolean isStaticallyInvocableType(MethodType mtype) {
1048 if (!isStaticallyNameable(mtype.returnType()))
1049 return false;
1050 for (Class<?> ptype : mtype.parameterArray())
1051 if (!isStaticallyNameable(ptype))
1052 return false;
1053 return true;
1054 }
1055
1056 static boolean isStaticallyNameable(Class<?> cls) {
1057 if (cls == Object.class)
1058 return true;
1059 if (MethodHandle.class.isAssignableFrom(cls)) {
1060 assert(!cls.isHidden());
1061 return true;
1062 }
1063 while (cls.isArray())
1064 cls = cls.getComponentType();
1065 if (cls.isPrimitive())
1066 return true; // int[].class, for example
1067 if (cls.isHidden())
1068 return false;
1069 if (ReflectUtil.isVMAnonymousClass(cls)) // FIXME: Unsafe::defineAnonymousClass to be removed
1070 return false;
1071 // could use VerifyAccess.isClassAccessible but the following is a safe approximation
1072 if (cls.getClassLoader() != Object.class.getClassLoader())
1073 return false;
1074 if (VerifyAccess.isSamePackage(MethodHandle.class, cls))
1075 return true;
1076 if (!Modifier.isPublic(cls.getModifiers()))
1077 return false;
1078 for (Class<?> pkgcls : STATICALLY_INVOCABLE_PACKAGES) {
1079 if (VerifyAccess.isSamePackage(pkgcls, cls))
1080 return true;
1081 }
1082 return false;
1083 }
1084
1085 void emitStaticInvoke(Name name) {
1086 emitStaticInvoke(name.function.member(), name);
1087 }
1088
1089 /**
1090 * Emit an invoke for the given name, using the MemberName directly.
1091 */
1092 void emitStaticInvoke(MemberName member, Name name) {
1093 assert(member.equals(name.function.member()));
1094 Class<?> defc = member.getDeclaringClass();
1095 String cname = getInternalName(defc);
1096 String mname = member.getName();
1097 String mtype;
1098 byte refKind = member.getReferenceKind();
1099 if (refKind == REF_invokeSpecial) {
1100 // in order to pass the verifier, we need to convert this to invokevirtual in all cases
1101 assert(member.canBeStaticallyBound()) : member;
1102 refKind = REF_invokeVirtual;
1103 }
1104
1105 assert(!(member.getDeclaringClass().isInterface() && refKind == REF_invokeVirtual));
1106
1107 // push arguments
1108 emitPushArguments(name, 0);
1109
1110 // invocation
1111 if (member.isMethod()) {
1112 mtype = member.getMethodType().toMethodDescriptorString();
1113 mv.visitMethodInsn(refKindOpcode(refKind), cname, mname, mtype,
1114 member.getDeclaringClass().isInterface());
1115 } else {
1116 mtype = MethodType.toFieldDescriptorString(member.getFieldType());
1117 mv.visitFieldInsn(refKindOpcode(refKind), cname, mname, mtype);
1118 }
1119 // Issue a type assertion for the result, so we can avoid casts later.
1120 if (name.type == L_TYPE) {
1121 Class<?> rtype = member.getInvocationType().returnType();
1122 assert(!rtype.isPrimitive());
1123 if (rtype != Object.class && !rtype.isInterface()) {
1124 assertStaticType(rtype, name);
1125 }
1126 }
1127 }
1128
1129 void emitNewArray(Name name) throws InternalError {
1130 Class<?> rtype = name.function.methodType().returnType();
1131 if (name.arguments.length == 0) {
1132 // The array will be a constant.
1133 Object emptyArray;
1134 try {
1135 emptyArray = name.function.resolvedHandle().invoke();
1136 } catch (Throwable ex) {
1137 throw uncaughtException(ex);
1138 }
1139 assert(java.lang.reflect.Array.getLength(emptyArray) == 0);
1140 assert(emptyArray.getClass() == rtype); // exact typing
1141 mv.visitFieldInsn(Opcodes.GETSTATIC, className(), classData(emptyArray), "Ljava/lang/Object;");
1142 emitReferenceCast(rtype, emptyArray);
1143 return;
1144 }
1145 Class<?> arrayElementType = rtype.getComponentType();
1146 assert(arrayElementType != null);
1147 emitIconstInsn(name.arguments.length);
1148 int xas = Opcodes.AASTORE;
1149 if (!arrayElementType.isPrimitive()) {
1150 mv.visitTypeInsn(Opcodes.ANEWARRAY, getInternalName(arrayElementType));
1151 } else {
1152 byte tc = arrayTypeCode(Wrapper.forPrimitiveType(arrayElementType));
1153 xas = arrayInsnOpcode(tc, xas);
1154 mv.visitIntInsn(Opcodes.NEWARRAY, tc);
1155 }
1156 // store arguments
1157 for (int i = 0; i < name.arguments.length; i++) {
1158 mv.visitInsn(Opcodes.DUP);
1159 emitIconstInsn(i);
1160 emitPushArgument(name, i);
1161 mv.visitInsn(xas);
1162 }
1163 // the array is left on the stack
1164 assertStaticType(rtype, name);
1165 }
1166 int refKindOpcode(byte refKind) {
1167 switch (refKind) {
1168 case REF_invokeVirtual: return Opcodes.INVOKEVIRTUAL;
1169 case REF_invokeStatic: return Opcodes.INVOKESTATIC;
1170 case REF_invokeSpecial: return Opcodes.INVOKESPECIAL;
1171 case REF_invokeInterface: return Opcodes.INVOKEINTERFACE;
1172 case REF_getField: return Opcodes.GETFIELD;
1173 case REF_putField: return Opcodes.PUTFIELD;
1174 case REF_getStatic: return Opcodes.GETSTATIC;
1175 case REF_putStatic: return Opcodes.PUTSTATIC;
1176 }
1177 throw new InternalError("refKind="+refKind);
1178 }
1179
1180 /**
1181 * Emit bytecode for the selectAlternative idiom.
1182 *
1183 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithTest):
1184 * <blockquote><pre>{@code
1185 * Lambda(a0:L,a1:I)=>{
1186 * t2:I=foo.test(a1:I);
1187 * t3:L=MethodHandleImpl.selectAlternative(t2:I,(MethodHandle(int)int),(MethodHandle(int)int));
1188 * t4:I=MethodHandle.invokeBasic(t3:L,a1:I);t4:I}
1189 * }</pre></blockquote>
1190 */
1191 private Name emitSelectAlternative(Name selectAlternativeName, Name invokeBasicName) {
1192 assert isStaticallyInvocable(invokeBasicName);
1193
1194 Name receiver = (Name) invokeBasicName.arguments[0];
1195
1196 Label L_fallback = new Label();
1197 Label L_done = new Label();
1198
1199 // load test result
1200 emitPushArgument(selectAlternativeName, 0);
1201
1202 // if_icmpne L_fallback
1203 mv.visitJumpInsn(Opcodes.IFEQ, L_fallback);
1204
1205 // invoke selectAlternativeName.arguments[1]
1206 Class<?>[] preForkClasses = localClasses.clone();
1207 emitPushArgument(selectAlternativeName, 1); // get 2nd argument of selectAlternative
1208 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
1209 emitStaticInvoke(invokeBasicName);
1210
1211 // goto L_done
1212 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1213
1214 // L_fallback:
1215 mv.visitLabel(L_fallback);
1216
1217 // invoke selectAlternativeName.arguments[2]
1218 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
1219 emitPushArgument(selectAlternativeName, 2); // get 3rd argument of selectAlternative
1220 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
1221 emitStaticInvoke(invokeBasicName);
1222
1223 // L_done:
1224 mv.visitLabel(L_done);
1225 // for now do not bother to merge typestate; just reset to the dominator state
1226 System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
1227
1228 return invokeBasicName; // return what's on stack
1229 }
1230
1231 /**
1232 * Emit bytecode for the guardWithCatch idiom.
1233 *
1234 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithCatch):
1235 * <blockquote><pre>{@code
1236 * guardWithCatch=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{
1237 * t8:L=MethodHandle.invokeBasic(a4:L,a6:L,a7:L);
1238 * t9:L=MethodHandleImpl.guardWithCatch(a1:L,a2:L,a3:L,t8:L);
1239 * t10:I=MethodHandle.invokeBasic(a5:L,t9:L);t10:I}
1240 * }</pre></blockquote>
1241 *
1242 * It is compiled into bytecode equivalent of the following code:
1243 * <blockquote><pre>{@code
1244 * try {
1245 * return a1.invokeBasic(a6, a7);
1246 * } catch (Throwable e) {
1247 * if (!a2.isInstance(e)) throw e;
1248 * return a3.invokeBasic(ex, a6, a7);
1249 * }}</pre></blockquote>
1250 */
1251 private Name emitGuardWithCatch(int pos) {
1252 Name args = lambdaForm.names[pos];
1253 Name invoker = lambdaForm.names[pos+1];
1254 Name result = lambdaForm.names[pos+2];
1255
1256 Label L_startBlock = new Label();
1257 Label L_endBlock = new Label();
1258 Label L_handler = new Label();
1259 Label L_done = new Label();
1260
1261 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1262 MethodType type = args.function.resolvedHandle().type()
1263 .dropParameterTypes(0,1)
1264 .changeReturnType(returnType);
1265
1266 mv.visitTryCatchBlock(L_startBlock, L_endBlock, L_handler, "java/lang/Throwable");
1267
1268 // Normal case
1269 mv.visitLabel(L_startBlock);
1270 // load target
1271 emitPushArgument(invoker, 0);
1272 emitPushArguments(args, 1); // skip 1st argument: method handle
1273 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
1274 mv.visitLabel(L_endBlock);
1275 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1276
1277 // Exceptional case
1278 mv.visitLabel(L_handler);
1279
1280 // Check exception's type
1281 mv.visitInsn(Opcodes.DUP);
1282 // load exception class
1283 emitPushArgument(invoker, 1);
1284 mv.visitInsn(Opcodes.SWAP);
1285 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Class", "isInstance", "(Ljava/lang/Object;)Z", false);
1286 Label L_rethrow = new Label();
1287 mv.visitJumpInsn(Opcodes.IFEQ, L_rethrow);
1288
1289 // Invoke catcher
1290 // load catcher
1291 emitPushArgument(invoker, 2);
1292 mv.visitInsn(Opcodes.SWAP);
1293 emitPushArguments(args, 1); // skip 1st argument: method handle
1294 MethodType catcherType = type.insertParameterTypes(0, Throwable.class);
1295 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", catcherType.basicType().toMethodDescriptorString(), false);
1296 mv.visitJumpInsn(Opcodes.GOTO, L_done);
1297
1298 mv.visitLabel(L_rethrow);
1299 mv.visitInsn(Opcodes.ATHROW);
1300
1301 mv.visitLabel(L_done);
1302
1303 return result;
1304 }
1305
1306 /**
1307 * Emit bytecode for the tryFinally idiom.
1308 * <p>
1309 * The pattern looks like (Cf. MethodHandleImpl.makeTryFinally):
1310 * <blockquote><pre>{@code
1311 * // a0: BMH
1312 * // a1: target, a2: cleanup
1313 * // a3: box, a4: unbox
1314 * // a5 (and following): arguments
1315 * tryFinally=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L)=>{
1316 * t6:L=MethodHandle.invokeBasic(a3:L,a5:L); // box the arguments into an Object[]
1317 * t7:L=MethodHandleImpl.tryFinally(a1:L,a2:L,t6:L); // call the tryFinally executor
1318 * t8:L=MethodHandle.invokeBasic(a4:L,t7:L);t8:L} // unbox the result; return the result
1319 * }</pre></blockquote>
1320 * <p>
1321 * It is compiled into bytecode equivalent to the following code:
1322 * <blockquote><pre>{@code
1323 * Throwable t;
1324 * Object r;
1325 * try {
1326 * r = a1.invokeBasic(a5);
1327 * } catch (Throwable thrown) {
1328 * t = thrown;
1329 * throw t;
1330 * } finally {
1331 * r = a2.invokeBasic(t, r, a5);
1332 * }
1333 * return r;
1334 * }</pre></blockquote>
1335 * <p>
1336 * Specifically, the bytecode will have the following form (the stack effects are given for the beginnings of
1337 * blocks, and for the situations after executing the given instruction - the code will have a slightly different
1338 * shape if the return type is {@code void}):
1339 * <blockquote><pre>{@code
1340 * TRY: (--)
1341 * load target (-- target)
1342 * load args (-- args... target)
1343 * INVOKEVIRTUAL MethodHandle.invokeBasic (depends)
1344 * FINALLY_NORMAL: (-- r_2nd* r)
1345 * store returned value (--)
1346 * load cleanup (-- cleanup)
1347 * ACONST_NULL (-- t cleanup)
1348 * load returned value (-- r_2nd* r t cleanup)
1349 * load args (-- args... r_2nd* r t cleanup)
1350 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r_2nd* r)
1351 * GOTO DONE
1352 * CATCH: (-- t)
1353 * DUP (-- t t)
1354 * FINALLY_EXCEPTIONAL: (-- t t)
1355 * load cleanup (-- cleanup t t)
1356 * SWAP (-- t cleanup t)
1357 * load default for r (-- r_2nd* r t cleanup t)
1358 * load args (-- args... r_2nd* r t cleanup t)
1359 * INVOKEVIRTUAL MethodHandle.invokeBasic (-- r_2nd* r t)
1360 * POP/POP2* (-- t)
1361 * ATHROW
1362 * DONE: (-- r)
1363 * }</pre></blockquote>
1364 * * = depends on whether the return type takes up 2 stack slots.
1365 */
1366 private Name emitTryFinally(int pos) {
1367 Name args = lambdaForm.names[pos];
1368 Name invoker = lambdaForm.names[pos+1];
1369 Name result = lambdaForm.names[pos+2];
1370
1371 Label lFrom = new Label();
1372 Label lTo = new Label();
1373 Label lCatch = new Label();
1374 Label lDone = new Label();
1375
1376 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1377 BasicType basicReturnType = BasicType.basicType(returnType);
1378 boolean isNonVoid = returnType != void.class;
1379
1380 MethodType type = args.function.resolvedHandle().type()
1381 .dropParameterTypes(0,1)
1382 .changeReturnType(returnType);
1383 MethodType cleanupType = type.insertParameterTypes(0, Throwable.class);
1384 if (isNonVoid) {
1385 cleanupType = cleanupType.insertParameterTypes(1, returnType);
1386 }
1387 String cleanupDesc = cleanupType.basicType().toMethodDescriptorString();
1388
1389 // exception handler table
1390 mv.visitTryCatchBlock(lFrom, lTo, lCatch, "java/lang/Throwable");
1391
1392 // TRY:
1393 mv.visitLabel(lFrom);
1394 emitPushArgument(invoker, 0); // load target
1395 emitPushArguments(args, 1); // load args (skip 0: method handle)
1396 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
1397 mv.visitLabel(lTo);
1398
1399 // FINALLY_NORMAL:
1400 int index = extendLocalsMap(new Class<?>[]{ returnType });
1401 if (isNonVoid) {
1402 emitStoreInsn(basicReturnType, index);
1403 }
1404 emitPushArgument(invoker, 1); // load cleanup
1405 mv.visitInsn(Opcodes.ACONST_NULL);
1406 if (isNonVoid) {
1407 emitLoadInsn(basicReturnType, index);
1408 }
1409 emitPushArguments(args, 1); // load args (skip 0: method handle)
1410 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", cleanupDesc, false);
1411 mv.visitJumpInsn(Opcodes.GOTO, lDone);
1412
1413 // CATCH:
1414 mv.visitLabel(lCatch);
1415 mv.visitInsn(Opcodes.DUP);
1416
1417 // FINALLY_EXCEPTIONAL:
1418 emitPushArgument(invoker, 1); // load cleanup
1419 mv.visitInsn(Opcodes.SWAP);
1420 if (isNonVoid) {
1421 emitZero(BasicType.basicType(returnType)); // load default for result
1422 }
1423 emitPushArguments(args, 1); // load args (skip 0: method handle)
1424 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", cleanupDesc, false);
1425 if (isNonVoid) {
1426 emitPopInsn(basicReturnType);
1427 }
1428 mv.visitInsn(Opcodes.ATHROW);
1429
1430 // DONE:
1431 mv.visitLabel(lDone);
1432
1433 return result;
1434 }
1435
1436 private void emitPopInsn(BasicType type) {
1437 mv.visitInsn(popInsnOpcode(type));
1438 }
1439
1440 private static int popInsnOpcode(BasicType type) {
1441 switch (type) {
1442 case I_TYPE:
1443 case F_TYPE:
1444 case L_TYPE:
1445 return Opcodes.POP;
1446 case J_TYPE:
1447 case D_TYPE:
1448 return Opcodes.POP2;
1449 default:
1450 throw new InternalError("unknown type: " + type);
1451 }
1452 }
1453
1454 /**
1455 * Emit bytecode for the loop idiom.
1456 * <p>
1457 * The pattern looks like (Cf. MethodHandleImpl.loop):
1458 * <blockquote><pre>{@code
1459 * // a0: BMH
1460 * // a1: LoopClauses (containing an array of arrays: inits, steps, preds, finis)
1461 * // a2: box, a3: unbox
1462 * // a4 (and following): arguments
1463 * loop=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L)=>{
1464 * t5:L=MethodHandle.invokeBasic(a2:L,a4:L); // box the arguments into an Object[]
1465 * t6:L=MethodHandleImpl.loop(bt:L,a1:L,t5:L); // call the loop executor (with supplied types in bt)
1466 * t7:L=MethodHandle.invokeBasic(a3:L,t6:L);t7:L} // unbox the result; return the result
1467 * }</pre></blockquote>
1468 * <p>
1469 * It is compiled into bytecode equivalent to the code seen in {@link MethodHandleImpl#loop(BasicType[],
1470 * MethodHandleImpl.LoopClauses, Object...)}, with the difference that no arrays
1471 * will be used for local state storage. Instead, the local state will be mapped to actual stack slots.
1472 * <p>
1473 * Bytecode generation applies an unrolling scheme to enable better bytecode generation regarding local state type
1474 * handling. The generated bytecode will have the following form ({@code void} types are ignored for convenience).
1475 * Assume there are {@code C} clauses in the loop.
1476 * <blockquote><pre>{@code
1477 * PREINIT: ALOAD_1
1478 * CHECKCAST LoopClauses
1479 * GETFIELD LoopClauses.clauses
1480 * ASTORE clauseDataIndex // place the clauses 2-dimensional array on the stack
1481 * INIT: (INIT_SEQ for clause 1)
1482 * ...
1483 * (INIT_SEQ for clause C)
1484 * LOOP: (LOOP_SEQ for clause 1)
1485 * ...
1486 * (LOOP_SEQ for clause C)
1487 * GOTO LOOP
1488 * DONE: ...
1489 * }</pre></blockquote>
1490 * <p>
1491 * The {@code INIT_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has
1492 * the following shape. Assume slot {@code vx} is used to hold the state for clause {@code x}.
1493 * <blockquote><pre>{@code
1494 * INIT_SEQ_x: ALOAD clauseDataIndex
1495 * ICONST_0
1496 * AALOAD // load the inits array
1497 * ICONST x
1498 * AALOAD // load the init handle for clause x
1499 * load args
1500 * INVOKEVIRTUAL MethodHandle.invokeBasic
1501 * store vx
1502 * }</pre></blockquote>
1503 * <p>
1504 * The {@code LOOP_SEQ_x} sequence for clause {@code x} (with {@code x} ranging from {@code 0} to {@code C-1}) has
1505 * the following shape. Again, assume slot {@code vx} is used to hold the state for clause {@code x}.
1506 * <blockquote><pre>{@code
1507 * LOOP_SEQ_x: ALOAD clauseDataIndex
1508 * ICONST_1
1509 * AALOAD // load the steps array
1510 * ICONST x
1511 * AALOAD // load the step handle for clause x
1512 * load locals
1513 * load args
1514 * INVOKEVIRTUAL MethodHandle.invokeBasic
1515 * store vx
1516 * ALOAD clauseDataIndex
1517 * ICONST_2
1518 * AALOAD // load the preds array
1519 * ICONST x
1520 * AALOAD // load the pred handle for clause x
1521 * load locals
1522 * load args
1523 * INVOKEVIRTUAL MethodHandle.invokeBasic
1524 * IFNE LOOP_SEQ_x+1 // predicate returned false -> jump to next clause
1525 * ALOAD clauseDataIndex
1526 * ICONST_3
1527 * AALOAD // load the finis array
1528 * ICONST x
1529 * AALOAD // load the fini handle for clause x
1530 * load locals
1531 * load args
1532 * INVOKEVIRTUAL MethodHandle.invokeBasic
1533 * GOTO DONE // jump beyond end of clauses to return from loop
1534 * }</pre></blockquote>
1535 */
1536 private Name emitLoop(int pos) {
1537 Name args = lambdaForm.names[pos];
1538 Name invoker = lambdaForm.names[pos+1];
1539 Name result = lambdaForm.names[pos+2];
1540
1541 // extract clause and loop-local state types
1542 // find the type info in the loop invocation
1543 BasicType[] loopClauseTypes = (BasicType[]) invoker.arguments[0];
1544 Class<?>[] loopLocalStateTypes = Stream.of(loopClauseTypes).
1545 filter(bt -> bt != BasicType.V_TYPE).map(BasicType::basicTypeClass).toArray(Class<?>[]::new);
1546 Class<?>[] localTypes = new Class<?>[loopLocalStateTypes.length + 1];
1547 localTypes[0] = MethodHandleImpl.LoopClauses.class;
1548 System.arraycopy(loopLocalStateTypes, 0, localTypes, 1, loopLocalStateTypes.length);
1549
1550 final int clauseDataIndex = extendLocalsMap(localTypes);
1551 final int firstLoopStateIndex = clauseDataIndex + 1;
1552
1553 Class<?> returnType = result.function.resolvedHandle().type().returnType();
1554 MethodType loopType = args.function.resolvedHandle().type()
1555 .dropParameterTypes(0,1)
1556 .changeReturnType(returnType);
1557 MethodType loopHandleType = loopType.insertParameterTypes(0, loopLocalStateTypes);
1558 MethodType predType = loopHandleType.changeReturnType(boolean.class);
1559 MethodType finiType = loopHandleType;
1560
1561 final int nClauses = loopClauseTypes.length;
1562
1563 // indices to invoker arguments to load method handle arrays
1564 final int inits = 1;
1565 final int steps = 2;
1566 final int preds = 3;
1567 final int finis = 4;
1568
1569 Label lLoop = new Label();
1570 Label lDone = new Label();
1571 Label lNext;
1572
1573 // PREINIT:
1574 emitPushArgument(MethodHandleImpl.LoopClauses.class, invoker.arguments[1]);
1575 mv.visitFieldInsn(Opcodes.GETFIELD, LOOP_CLAUSES, "clauses", MHARY2);
1576 emitAstoreInsn(clauseDataIndex);
1577
1578 // INIT:
1579 for (int c = 0, state = 0; c < nClauses; ++c) {
1580 MethodType cInitType = loopType.changeReturnType(loopClauseTypes[c].basicTypeClass());
1581 emitLoopHandleInvoke(invoker, inits, c, args, false, cInitType, loopLocalStateTypes, clauseDataIndex,
1582 firstLoopStateIndex);
1583 if (cInitType.returnType() != void.class) {
1584 emitStoreInsn(BasicType.basicType(cInitType.returnType()), firstLoopStateIndex + state);
1585 ++state;
1586 }
1587 }
1588
1589 // LOOP:
1590 mv.visitLabel(lLoop);
1591
1592 for (int c = 0, state = 0; c < nClauses; ++c) {
1593 lNext = new Label();
1594
1595 MethodType stepType = loopHandleType.changeReturnType(loopClauseTypes[c].basicTypeClass());
1596 boolean isVoid = stepType.returnType() == void.class;
1597
1598 // invoke loop step
1599 emitLoopHandleInvoke(invoker, steps, c, args, true, stepType, loopLocalStateTypes, clauseDataIndex,
1600 firstLoopStateIndex);
1601 if (!isVoid) {
1602 emitStoreInsn(BasicType.basicType(stepType.returnType()), firstLoopStateIndex + state);
1603 ++state;
1604 }
1605
1606 // invoke loop predicate
1607 emitLoopHandleInvoke(invoker, preds, c, args, true, predType, loopLocalStateTypes, clauseDataIndex,
1608 firstLoopStateIndex);
1609 mv.visitJumpInsn(Opcodes.IFNE, lNext);
1610
1611 // invoke fini
1612 emitLoopHandleInvoke(invoker, finis, c, args, true, finiType, loopLocalStateTypes, clauseDataIndex,
1613 firstLoopStateIndex);
1614 mv.visitJumpInsn(Opcodes.GOTO, lDone);
1615
1616 // this is the beginning of the next loop clause
1617 mv.visitLabel(lNext);
1618 }
1619
1620 mv.visitJumpInsn(Opcodes.GOTO, lLoop);
1621
1622 // DONE:
1623 mv.visitLabel(lDone);
1624
1625 return result;
1626 }
1627
1628 private int extendLocalsMap(Class<?>[] types) {
1629 int firstSlot = localsMap.length - 1;
1630 localsMap = Arrays.copyOf(localsMap, localsMap.length + types.length);
1631 localClasses = Arrays.copyOf(localClasses, localClasses.length + types.length);
1632 System.arraycopy(types, 0, localClasses, firstSlot, types.length);
1633 int index = localsMap[firstSlot - 1] + 1;
1634 int lastSlots = 0;
1635 for (int i = 0; i < types.length; ++i) {
1636 localsMap[firstSlot + i] = index;
1637 lastSlots = BasicType.basicType(localClasses[firstSlot + i]).basicTypeSlots();
1638 index += lastSlots;
1639 }
1640 localsMap[localsMap.length - 1] = index - lastSlots;
1641 return firstSlot;
1642 }
1643
1644 private void emitLoopHandleInvoke(Name holder, int handles, int clause, Name args, boolean pushLocalState,
1645 MethodType type, Class<?>[] loopLocalStateTypes, int clauseDataSlot,
1646 int firstLoopStateSlot) {
1647 // load handle for clause
1648 emitPushClauseArray(clauseDataSlot, handles);
1649 emitIconstInsn(clause);
1650 mv.visitInsn(Opcodes.AALOAD);
1651 // load loop state (preceding the other arguments)
1652 if (pushLocalState) {
1653 for (int s = 0; s < loopLocalStateTypes.length; ++s) {
1654 emitLoadInsn(BasicType.basicType(loopLocalStateTypes[s]), firstLoopStateSlot + s);
1655 }
1656 }
1657 // load loop args (skip 0: method handle)
1658 emitPushArguments(args, 1);
1659 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.toMethodDescriptorString(), false);
1660 }
1661
1662 private void emitPushClauseArray(int clauseDataSlot, int which) {
1663 emitAloadInsn(clauseDataSlot);
1664 emitIconstInsn(which - 1);
1665 mv.visitInsn(Opcodes.AALOAD);
1666 }
1667
1668 private void emitZero(BasicType type) {
1669 switch (type) {
1670 case I_TYPE: mv.visitInsn(Opcodes.ICONST_0); break;
1671 case J_TYPE: mv.visitInsn(Opcodes.LCONST_0); break;
1672 case F_TYPE: mv.visitInsn(Opcodes.FCONST_0); break;
1673 case D_TYPE: mv.visitInsn(Opcodes.DCONST_0); break;
1674 case L_TYPE: mv.visitInsn(Opcodes.ACONST_NULL); break;
1675 default: throw new InternalError("unknown type: " + type);
1676 }
1677 }
1678
1679 private void emitPushArguments(Name args, int start) {
1680 MethodType type = args.function.methodType();
1681 for (int i = start; i < args.arguments.length; i++) {
1682 emitPushArgument(type.parameterType(i), args.arguments[i]);
1683 }
1684 }
1685
1686 private void emitPushArgument(Name name, int paramIndex) {
1687 Object arg = name.arguments[paramIndex];
1688 Class<?> ptype = name.function.methodType().parameterType(paramIndex);
1689 emitPushArgument(ptype, arg);
1690 }
1691
1692 private void emitPushArgument(Class<?> ptype, Object arg) {
1693 BasicType bptype = basicType(ptype);
1694 if (arg instanceof Name) {
1695 Name n = (Name) arg;
1696 emitLoadInsn(n.type, n.index());
1697 emitImplicitConversion(n.type, ptype, n);
1698 } else if ((arg == null || arg instanceof String) && bptype == L_TYPE) {
1699 emitConst(arg);
1700 } else {
1701 if (Wrapper.isWrapperType(arg.getClass()) && bptype != L_TYPE) {
1702 emitConst(arg);
1703 } else {
1704 mv.visitFieldInsn(Opcodes.GETSTATIC, className(), classData(arg), "Ljava/lang/Object;");
1705 emitImplicitConversion(L_TYPE, ptype, arg);
1706 }
1707 }
1708 }
1709
1710 /**
1711 * Store the name to its local, if necessary.
1712 */
1713 private void emitStoreResult(Name name) {
1714 if (name != null && name.type != V_TYPE) {
1715 // non-void: actually assign
1716 emitStoreInsn(name.type, name.index());
1717 }
1718 }
1719
1720 /**
1721 * Emits a return statement from a LF invoker. If required, the result type is cast to the correct return type.
1722 */
1723 private void emitReturn(Name onStack) {
1724 // return statement
1725 Class<?> rclass = invokerType.returnType();
1726 BasicType rtype = lambdaForm.returnType();
1727 assert(rtype == basicType(rclass)); // must agree
1728 if (rtype == V_TYPE) {
1729 // void
1730 mv.visitInsn(Opcodes.RETURN);
1731 // it doesn't matter what rclass is; the JVM will discard any value
1732 } else {
1733 LambdaForm.Name rn = lambdaForm.names[lambdaForm.result];
1734
1735 // put return value on the stack if it is not already there
1736 if (rn != onStack) {
1737 emitLoadInsn(rtype, lambdaForm.result);
1738 }
1739
1740 emitImplicitConversion(rtype, rclass, rn);
1741
1742 // generate actual return statement
1743 emitReturnInsn(rtype);
1744 }
1745 }
1746
1747 /**
1748 * Emit a type conversion bytecode casting from "from" to "to".
1749 */
1750 private void emitPrimCast(Wrapper from, Wrapper to) {
1751 // Here's how.
1752 // - indicates forbidden
1753 // <-> indicates implicit
1754 // to ----> boolean byte short char int long float double
1755 // from boolean <-> - - - - - - -
1756 // byte - <-> i2s i2c <-> i2l i2f i2d
1757 // short - i2b <-> i2c <-> i2l i2f i2d
1758 // char - i2b i2s <-> <-> i2l i2f i2d
1759 // int - i2b i2s i2c <-> i2l i2f i2d
1760 // long - l2i,i2b l2i,i2s l2i,i2c l2i <-> l2f l2d
1761 // float - f2i,i2b f2i,i2s f2i,i2c f2i f2l <-> f2d
1762 // double - d2i,i2b d2i,i2s d2i,i2c d2i d2l d2f <->
1763 if (from == to) {
1764 // no cast required, should be dead code anyway
1765 return;
1766 }
1767 if (from.isSubwordOrInt()) {
1768 // cast from {byte,short,char,int} to anything
1769 emitI2X(to);
1770 } else {
1771 // cast from {long,float,double} to anything
1772 if (to.isSubwordOrInt()) {
1773 // cast to {byte,short,char,int}
1774 emitX2I(from);
1775 if (to.bitWidth() < 32) {
1776 // targets other than int require another conversion
1777 emitI2X(to);
1778 }
1779 } else {
1780 // cast to {long,float,double} - this is verbose
1781 boolean error = false;
1782 switch (from) {
1783 case LONG:
1784 switch (to) {
1785 case FLOAT: mv.visitInsn(Opcodes.L2F); break;
1786 case DOUBLE: mv.visitInsn(Opcodes.L2D); break;
1787 default: error = true; break;
1788 }
1789 break;
1790 case FLOAT:
1791 switch (to) {
1792 case LONG : mv.visitInsn(Opcodes.F2L); break;
1793 case DOUBLE: mv.visitInsn(Opcodes.F2D); break;
1794 default: error = true; break;
1795 }
1796 break;
1797 case DOUBLE:
1798 switch (to) {
1799 case LONG : mv.visitInsn(Opcodes.D2L); break;
1800 case FLOAT: mv.visitInsn(Opcodes.D2F); break;
1801 default: error = true; break;
1802 }
1803 break;
1804 default:
1805 error = true;
1806 break;
1807 }
1808 if (error) {
1809 throw new IllegalStateException("unhandled prim cast: " + from + "2" + to);
1810 }
1811 }
1812 }
1813 }
1814
1815 private void emitI2X(Wrapper type) {
1816 switch (type) {
1817 case BYTE: mv.visitInsn(Opcodes.I2B); break;
1818 case SHORT: mv.visitInsn(Opcodes.I2S); break;
1819 case CHAR: mv.visitInsn(Opcodes.I2C); break;
1820 case INT: /* naught */ break;
1821 case LONG: mv.visitInsn(Opcodes.I2L); break;
1822 case FLOAT: mv.visitInsn(Opcodes.I2F); break;
1823 case DOUBLE: mv.visitInsn(Opcodes.I2D); break;
1824 case BOOLEAN:
1825 // For compatibility with ValueConversions and explicitCastArguments:
1826 mv.visitInsn(Opcodes.ICONST_1);
1827 mv.visitInsn(Opcodes.IAND);
1828 break;
1829 default: throw new InternalError("unknown type: " + type);
1830 }
1831 }
1832
1833 private void emitX2I(Wrapper type) {
1834 switch (type) {
1835 case LONG: mv.visitInsn(Opcodes.L2I); break;
1836 case FLOAT: mv.visitInsn(Opcodes.F2I); break;
1837 case DOUBLE: mv.visitInsn(Opcodes.D2I); break;
1838 default: throw new InternalError("unknown type: " + type);
1839 }
1840 }
1841
1842 /**
1843 * Generate bytecode for a LambdaForm.vmentry which calls interpretWithArguments.
1844 */
1845 static MemberName generateLambdaFormInterpreterEntryPoint(MethodType mt) {
1846 assert(isValidSignature(basicTypeSignature(mt)));
1847 String name = "interpret_"+basicTypeChar(mt.returnType());
1848 MethodType type = mt; // includes leading argument
1849 type = type.changeParameterType(0, MethodHandle.class);
1850 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("LFI", name, type);
1851 return g.loadMethod(g.generateLambdaFormInterpreterEntryPointBytes());
1852 }
1853
1854 private byte[] generateLambdaFormInterpreterEntryPointBytes() {
1855 classFilePrologue();
1856 methodPrologue();
1857
1858 // Suppress this method in backtraces displayed to the user.
1859 mv.visitAnnotation(HIDDEN_SIG, true);
1860
1861 // Don't inline the interpreter entry.
1862 mv.visitAnnotation(DONTINLINE_SIG, true);
1863
1864 // create parameter array
1865 emitIconstInsn(invokerType.parameterCount());
1866 mv.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object");
1867
1868 // fill parameter array
1869 for (int i = 0; i < invokerType.parameterCount(); i++) {
1870 Class<?> ptype = invokerType.parameterType(i);
1871 mv.visitInsn(Opcodes.DUP);
1872 emitIconstInsn(i);
1873 emitLoadInsn(basicType(ptype), i);
1874 // box if primitive type
1875 if (ptype.isPrimitive()) {
1876 emitBoxing(Wrapper.forPrimitiveType(ptype));
1877 }
1878 mv.visitInsn(Opcodes.AASTORE);
1879 }
1880 // invoke
1881 emitAloadInsn(0);
1882 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", "Ljava/lang/invoke/LambdaForm;");
1883 mv.visitInsn(Opcodes.SWAP); // swap form and array; avoid local variable
1884 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, LF, "interpretWithArguments", "([Ljava/lang/Object;)Ljava/lang/Object;", false);
1885
1886 // maybe unbox
1887 Class<?> rtype = invokerType.returnType();
1888 if (rtype.isPrimitive() && rtype != void.class) {
1889 emitUnboxing(Wrapper.forPrimitiveType(rtype));
1890 }
1891
1892 // return statement
1893 emitReturnInsn(basicType(rtype));
1894
1895 methodEpilogue();
1896 clinit();
1897 bogusMethod(invokerType);
1898
1899 final byte[] classFile = cw.toByteArray();
1900 maybeDump(classFile);
1901 return classFile;
1902 }
1903
1904 /**
1905 * Generate bytecode for a NamedFunction invoker.
1906 */
1907 static MemberName generateNamedFunctionInvoker(MethodTypeForm typeForm) {
1908 MethodType invokerType = NamedFunction.INVOKER_METHOD_TYPE;
1909 String invokerName = "invoke_" + shortenSignature(basicTypeSignature(typeForm.erasedType()));
1910 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("NFI", invokerName, invokerType);
1911 return g.loadMethod(g.generateNamedFunctionInvokerImpl(typeForm));
1912 }
1913
1914 private byte[] generateNamedFunctionInvokerImpl(MethodTypeForm typeForm) {
1915 MethodType dstType = typeForm.erasedType();
1916 classFilePrologue();
1917 methodPrologue();
1918
1919 // Suppress this method in backtraces displayed to the user.
1920 mv.visitAnnotation(HIDDEN_SIG, true);
1921
1922 // Force inlining of this invoker method.
1923 mv.visitAnnotation(FORCEINLINE_SIG, true);
1924
1925 // Load receiver
1926 emitAloadInsn(0);
1927
1928 // Load arguments from array
1929 for (int i = 0; i < dstType.parameterCount(); i++) {
1930 emitAloadInsn(1);
1931 emitIconstInsn(i);
1932 mv.visitInsn(Opcodes.AALOAD);
1933
1934 // Maybe unbox
1935 Class<?> dptype = dstType.parameterType(i);
1936 if (dptype.isPrimitive()) {
1937 Wrapper dstWrapper = Wrapper.forBasicType(dptype);
1938 Wrapper srcWrapper = dstWrapper.isSubwordOrInt() ? Wrapper.INT : dstWrapper; // narrow subword from int
1939 emitUnboxing(srcWrapper);
1940 emitPrimCast(srcWrapper, dstWrapper);
1941 }
1942 }
1943
1944 // Invoke
1945 String targetDesc = dstType.basicType().toMethodDescriptorString();
1946 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", targetDesc, false);
1947
1948 // Box primitive types
1949 Class<?> rtype = dstType.returnType();
1950 if (rtype != void.class && rtype.isPrimitive()) {
1951 Wrapper srcWrapper = Wrapper.forBasicType(rtype);
1952 Wrapper dstWrapper = srcWrapper.isSubwordOrInt() ? Wrapper.INT : srcWrapper; // widen subword to int
1953 // boolean casts not allowed
1954 emitPrimCast(srcWrapper, dstWrapper);
1955 emitBoxing(dstWrapper);
1956 }
1957
1958 // If the return type is void we return a null reference.
1959 if (rtype == void.class) {
1960 mv.visitInsn(Opcodes.ACONST_NULL);
1961 }
1962 emitReturnInsn(L_TYPE); // NOTE: NamedFunction invokers always return a reference value.
1963
1964 methodEpilogue();
1965 clinit();
1966 bogusMethod(dstType);
1967
1968 final byte[] classFile = cw.toByteArray();
1969 maybeDump(classFile);
1970 return classFile;
1971 }
1972
1973 /**
1974 * Emit a bogus method that just loads some string constants. This is to get the constants into the constant pool
1975 * for debugging purposes.
1976 */
1977 private void bogusMethod(Object os) {
1978 if (DUMP_CLASS_FILES) {
1979 mv = cw.visitMethod(Opcodes.ACC_STATIC, "dummy", "()V", null, null);
1980 mv.visitLdcInsn(os.toString());
1981 mv.visitInsn(Opcodes.POP);
1982 mv.visitInsn(Opcodes.RETURN);
1983 mv.visitMaxs(0, 0);
1984 mv.visitEnd();
1985 }
1986 }
1987 }