1 /*
2 * Copyright (c) 2008, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang.invoke;
27
28 import sun.misc.Unsafe;
29 import java.lang.reflect.Method;
30 import java.util.Arrays;
31 import sun.invoke.util.VerifyAccess;
32 import static java.lang.invoke.MethodHandleNatives.Constants.*;
33 import static java.lang.invoke.LambdaForm.*;
34 import static java.lang.invoke.LambdaForm.BasicType.*;
35 import static java.lang.invoke.MethodTypeForm.*;
36 import static java.lang.invoke.MethodHandleStatics.*;
37 import java.lang.ref.WeakReference;
38 import java.lang.reflect.Field;
39 import sun.invoke.util.ValueConversions;
40 import sun.invoke.util.VerifyType;
41 import sun.invoke.util.Wrapper;
42
43 /**
44 * The flavor of method handle which implements a constant reference
45 * to a class member.
46 * @author jrose
47 */
48 class DirectMethodHandle extends MethodHandle {
49 final MemberName member;
50
51 // Constructors and factory methods in this class *must* be package scoped or private.
52 private DirectMethodHandle(MethodType mtype, LambdaForm form, MemberName member) {
53 super(mtype, form);
54 if (!member.isResolved()) throw new InternalError();
55
56 if (member.getDeclaringClass().isInterface() &&
57 member.isMethod() && !member.isAbstract()) {
58 // Check for corner case: invokeinterface of Object method
59 MemberName m = new MemberName(Object.class, member.getName(), member.getMethodType(), member.getReferenceKind());
60 m = MemberName.getFactory().resolveOrNull(m.getReferenceKind(), m, null);
61 if (m != null && m.isPublic()) {
62 member = m;
63 }
64 }
65
66 this.member = member;
67 }
68
69 // Factory methods:
70 static DirectMethodHandle make(byte refKind, Class<?> receiver, MemberName member) {
71 MethodType mtype = member.getMethodOrFieldType();
72 if (!member.isStatic()) {
73 if (!member.getDeclaringClass().isAssignableFrom(receiver) || member.isConstructor())
74 throw new InternalError(member.toString());
75 mtype = mtype.insertParameterTypes(0, receiver);
76 }
77 if (!member.isField()) {
78 if (refKind == REF_invokeSpecial) {
79 member = member.asSpecial();
80 LambdaForm lform = preparedLambdaForm(member);
81 return new Special(mtype, lform, member);
82 } else {
83 LambdaForm lform = preparedLambdaForm(member);
84 return new DirectMethodHandle(mtype, lform, member);
85 }
86 } else {
87 LambdaForm lform = preparedFieldLambdaForm(member);
88 if (member.isStatic()) {
89 long offset = MethodHandleNatives.staticFieldOffset(member);
90 Object base = MethodHandleNatives.staticFieldBase(member);
91 return new StaticAccessor(mtype, lform, member, base, offset);
92 } else {
93 long offset = MethodHandleNatives.objectFieldOffset(member);
94 assert(offset == (int)offset);
95 return new Accessor(mtype, lform, member, (int)offset);
96 }
97 }
98 }
99 static DirectMethodHandle make(Class<?> receiver, MemberName member) {
100 byte refKind = member.getReferenceKind();
101 if (refKind == REF_invokeSpecial)
102 refKind = REF_invokeVirtual;
103 return make(refKind, receiver, member);
104 }
105 static DirectMethodHandle make(MemberName member) {
106 if (member.isConstructor())
107 return makeAllocator(member);
108 return make(member.getDeclaringClass(), member);
109 }
110 static DirectMethodHandle make(Method method) {
111 return make(method.getDeclaringClass(), new MemberName(method));
112 }
113 static DirectMethodHandle make(Field field) {
114 return make(field.getDeclaringClass(), new MemberName(field));
115 }
116 private static DirectMethodHandle makeAllocator(MemberName ctor) {
117 assert(ctor.isConstructor() && ctor.getName().equals("<init>"));
118 Class<?> instanceClass = ctor.getDeclaringClass();
119 ctor = ctor.asConstructor();
120 assert(ctor.isConstructor() && ctor.getReferenceKind() == REF_newInvokeSpecial) : ctor;
121 MethodType mtype = ctor.getMethodType().changeReturnType(instanceClass);
122 LambdaForm lform = preparedLambdaForm(ctor);
123 MemberName init = ctor.asSpecial();
124 assert(init.getMethodType().returnType() == void.class);
125 return new Constructor(mtype, lform, ctor, init, instanceClass);
126 }
127
128 @Override
129 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
130 return new DirectMethodHandle(mt, lf, member);
131 }
132
133 @Override
134 String internalProperties() {
135 return "/DMH="+member.toString();
136 }
137
138 //// Implementation methods.
139 @Override
140 MethodHandle viewAsType(MethodType newType) {
141 return new DirectMethodHandle(newType, form, member);
142 }
143 @Override
144 @ForceInline
145 MemberName internalMemberName() {
146 return member;
147 }
148
149 @Override
150 MethodHandle bindArgument(int pos, BasicType basicType, Object value) {
151 // If the member needs dispatching, do so.
152 if (pos == 0 && basicType == L_TYPE) {
153 DirectMethodHandle concrete = maybeRebind(value);
154 if (concrete != null)
155 return concrete.bindReceiver(value);
156 }
157 return super.bindArgument(pos, basicType, value);
158 }
159
160 @Override
161 MethodHandle bindReceiver(Object receiver) {
162 // If the member needs dispatching, do so.
163 DirectMethodHandle concrete = maybeRebind(receiver);
164 if (concrete != null)
165 return concrete.bindReceiver(receiver);
166 return super.bindReceiver(receiver);
167 }
168
169 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
170
171 private DirectMethodHandle maybeRebind(Object receiver) {
172 if (receiver != null) {
173 switch (member.getReferenceKind()) {
174 case REF_invokeInterface:
175 case REF_invokeVirtual:
176 // Pre-dispatch the member.
177 Class<?> concreteClass = receiver.getClass();
178 MemberName concrete = new MemberName(concreteClass, member.getName(), member.getMethodType(), REF_invokeSpecial);
179 concrete = IMPL_NAMES.resolveOrNull(REF_invokeSpecial, concrete, concreteClass);
180 if (concrete != null)
181 return new DirectMethodHandle(type(), preparedLambdaForm(concrete), concrete);
182 break;
183 }
184 }
185 return null;
186 }
187
188 /**
189 * Create a LF which can invoke the given method.
190 * Cache and share this structure among all methods with
191 * the same basicType and refKind.
192 */
193 private static LambdaForm preparedLambdaForm(MemberName m) {
194 assert(m.isInvocable()) : m; // call preparedFieldLambdaForm instead
195 MethodType mtype = m.getInvocationType().basicType();
196 assert(!m.isMethodHandleInvoke() || "invokeBasic".equals(m.getName())) : m;
197 int which;
198 switch (m.getReferenceKind()) {
199 case REF_invokeVirtual: which = LF_INVVIRTUAL; break;
200 case REF_invokeStatic: which = LF_INVSTATIC; break;
201 case REF_invokeSpecial: which = LF_INVSPECIAL; break;
202 case REF_invokeInterface: which = LF_INVINTERFACE; break;
203 case REF_newInvokeSpecial: which = LF_NEWINVSPECIAL; break;
204 default: throw new InternalError(m.toString());
205 }
206 if (which == LF_INVSTATIC && shouldBeInitialized(m)) {
207 // precompute the barrier-free version:
208 preparedLambdaForm(mtype, which);
209 which = LF_INVSTATIC_INIT;
210 }
211 LambdaForm lform = preparedLambdaForm(mtype, which);
212 maybeCompile(lform, m);
213 assert(lform.methodType().dropParameterTypes(0, 1)
214 .equals(m.getInvocationType().basicType()))
215 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
216 return lform;
217 }
218
219 private static LambdaForm preparedLambdaForm(MethodType mtype, int which) {
220 LambdaForm lform = mtype.form().cachedLambdaForm(which);
221 if (lform != null) return lform;
222 lform = makePreparedLambdaForm(mtype, which);
223 return mtype.form().setCachedLambdaForm(which, lform);
224 }
225
226 private static LambdaForm makePreparedLambdaForm(MethodType mtype, int which) {
227 boolean needsInit = (which == LF_INVSTATIC_INIT);
228 boolean doesAlloc = (which == LF_NEWINVSPECIAL);
229 String linkerName, lambdaName;
230 switch (which) {
231 case LF_INVVIRTUAL: linkerName = "linkToVirtual"; lambdaName = "DMH.invokeVirtual"; break;
232 case LF_INVSTATIC: linkerName = "linkToStatic"; lambdaName = "DMH.invokeStatic"; break;
233 case LF_INVSTATIC_INIT:linkerName = "linkToStatic"; lambdaName = "DMH.invokeStaticInit"; break;
234 case LF_INVSPECIAL: linkerName = "linkToSpecial"; lambdaName = "DMH.invokeSpecial"; break;
235 case LF_INVINTERFACE: linkerName = "linkToInterface"; lambdaName = "DMH.invokeInterface"; break;
236 case LF_NEWINVSPECIAL: linkerName = "linkToSpecial"; lambdaName = "DMH.newInvokeSpecial"; break;
237 default: throw new InternalError("which="+which);
238 }
239 MethodType mtypeWithArg = mtype.appendParameterTypes(MemberName.class);
240 if (doesAlloc)
241 mtypeWithArg = mtypeWithArg
242 .insertParameterTypes(0, Object.class) // insert newly allocated obj
243 .changeReturnType(void.class); // <init> returns void
244 MemberName linker = new MemberName(MethodHandle.class, linkerName, mtypeWithArg, REF_invokeStatic);
245 try {
246 linker = IMPL_NAMES.resolveOrFail(REF_invokeStatic, linker, null, NoSuchMethodException.class);
247 } catch (ReflectiveOperationException ex) {
248 throw newInternalError(ex);
249 }
250 final int DMH_THIS = 0;
251 final int ARG_BASE = 1;
252 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
253 int nameCursor = ARG_LIMIT;
254 final int NEW_OBJ = (doesAlloc ? nameCursor++ : -1);
255 final int GET_MEMBER = nameCursor++;
256 final int LINKER_CALL = nameCursor++;
257 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
258 assert(names.length == nameCursor);
259 if (doesAlloc) {
260 // names = { argx,y,z,... new C, init method }
261 names[NEW_OBJ] = new Name(Lazy.NF_allocateInstance, names[DMH_THIS]);
262 names[GET_MEMBER] = new Name(Lazy.NF_constructorMethod, names[DMH_THIS]);
263 } else if (needsInit) {
264 names[GET_MEMBER] = new Name(Lazy.NF_internalMemberNameEnsureInit, names[DMH_THIS]);
265 } else {
266 names[GET_MEMBER] = new Name(Lazy.NF_internalMemberName, names[DMH_THIS]);
267 }
268 assert(findDirectMethodHandle(names[GET_MEMBER]) == names[DMH_THIS]);
269 Object[] outArgs = Arrays.copyOfRange(names, ARG_BASE, GET_MEMBER+1, Object[].class);
270 assert(outArgs[outArgs.length-1] == names[GET_MEMBER]); // look, shifted args!
271 int result = LAST_RESULT;
272 if (doesAlloc) {
273 assert(outArgs[outArgs.length-2] == names[NEW_OBJ]); // got to move this one
274 System.arraycopy(outArgs, 0, outArgs, 1, outArgs.length-2);
275 outArgs[0] = names[NEW_OBJ];
276 result = NEW_OBJ;
277 }
278 names[LINKER_CALL] = new Name(linker, outArgs);
279 lambdaName += "_" + shortenSignature(basicTypeSignature(mtype));
280 LambdaForm lform = new LambdaForm(lambdaName, ARG_LIMIT, names, result);
281 // This is a tricky bit of code. Don't send it through the LF interpreter.
282 lform.compileToBytecode();
283 return lform;
284 }
285
286 static Object findDirectMethodHandle(Name name) {
287 if (name.function == Lazy.NF_internalMemberName ||
288 name.function == Lazy.NF_internalMemberNameEnsureInit ||
289 name.function == Lazy.NF_constructorMethod) {
290 assert(name.arguments.length == 1);
291 return name.arguments[0];
292 }
293 return null;
294 }
295
296 private static void maybeCompile(LambdaForm lform, MemberName m) {
297 if (VerifyAccess.isSamePackage(m.getDeclaringClass(), MethodHandle.class))
298 // Help along bootstrapping...
299 lform.compileToBytecode();
300 }
301
302 /** Static wrapper for DirectMethodHandle.internalMemberName. */
303 @ForceInline
304 /*non-public*/ static Object internalMemberName(Object mh) {
305 return ((DirectMethodHandle)mh).member;
306 }
307
308 /** Static wrapper for DirectMethodHandle.internalMemberName.
309 * This one also forces initialization.
310 */
311 /*non-public*/ static Object internalMemberNameEnsureInit(Object mh) {
312 DirectMethodHandle dmh = (DirectMethodHandle)mh;
313 dmh.ensureInitialized();
314 return dmh.member;
315 }
316
317 /*non-public*/ static
318 boolean shouldBeInitialized(MemberName member) {
319 switch (member.getReferenceKind()) {
320 case REF_invokeStatic:
321 case REF_getStatic:
322 case REF_putStatic:
323 case REF_newInvokeSpecial:
324 break;
325 default:
326 // No need to initialize the class on this kind of member.
327 return false;
328 }
329 Class<?> cls = member.getDeclaringClass();
330 if (cls == ValueConversions.class ||
331 cls == MethodHandleImpl.class ||
332 cls == Invokers.class) {
333 // These guys have lots of <clinit> DMH creation but we know
334 // the MHs will not be used until the system is booted.
335 return false;
336 }
337 if (VerifyAccess.isSamePackage(MethodHandle.class, cls) ||
338 VerifyAccess.isSamePackage(ValueConversions.class, cls)) {
339 // It is a system class. It is probably in the process of
340 // being initialized, but we will help it along just to be safe.
341 if (UNSAFE.shouldBeInitialized(cls)) {
342 UNSAFE.ensureClassInitialized(cls);
343 }
344 return false;
345 }
346 return UNSAFE.shouldBeInitialized(cls);
347 }
348
349 private static class EnsureInitialized extends ClassValue<WeakReference<Thread>> {
350 @Override
351 protected WeakReference<Thread> computeValue(Class<?> type) {
352 UNSAFE.ensureClassInitialized(type);
353 if (UNSAFE.shouldBeInitialized(type))
354 // If the previous call didn't block, this can happen.
355 // We are executing inside <clinit>.
356 return new WeakReference<>(Thread.currentThread());
357 return null;
358 }
359 static final EnsureInitialized INSTANCE = new EnsureInitialized();
360 }
361
362 private void ensureInitialized() {
363 if (checkInitialized(member)) {
364 // The coast is clear. Delete the <clinit> barrier.
365 if (member.isField())
366 updateForm(preparedFieldLambdaForm(member));
367 else
368 updateForm(preparedLambdaForm(member));
369 }
370 }
371 private static boolean checkInitialized(MemberName member) {
372 Class<?> defc = member.getDeclaringClass();
373 WeakReference<Thread> ref = EnsureInitialized.INSTANCE.get(defc);
374 if (ref == null) {
375 return true; // the final state
376 }
377 Thread clinitThread = ref.get();
378 // Somebody may still be running defc.<clinit>.
379 if (clinitThread == Thread.currentThread()) {
380 // If anybody is running defc.<clinit>, it is this thread.
381 if (UNSAFE.shouldBeInitialized(defc))
382 // Yes, we are running it; keep the barrier for now.
383 return false;
384 } else {
385 // We are in a random thread. Block.
386 UNSAFE.ensureClassInitialized(defc);
387 }
388 assert(!UNSAFE.shouldBeInitialized(defc));
389 // put it into the final state
390 EnsureInitialized.INSTANCE.remove(defc);
391 return true;
392 }
393
394 /*non-public*/ static void ensureInitialized(Object mh) {
395 ((DirectMethodHandle)mh).ensureInitialized();
396 }
397
398 /** This subclass represents invokespecial instructions. */
399 static class Special extends DirectMethodHandle {
400 private Special(MethodType mtype, LambdaForm form, MemberName member) {
401 super(mtype, form, member);
402 }
403 @Override
404 boolean isInvokeSpecial() {
405 return true;
406 }
407 @Override
408 MethodHandle viewAsType(MethodType newType) {
409 return new Special(newType, form, member);
410 }
411 }
412
413 /** This subclass handles constructor references. */
414 static class Constructor extends DirectMethodHandle {
415 final MemberName initMethod;
416 final Class<?> instanceClass;
417
418 private Constructor(MethodType mtype, LambdaForm form, MemberName constructor,
419 MemberName initMethod, Class<?> instanceClass) {
420 super(mtype, form, constructor);
421 this.initMethod = initMethod;
422 this.instanceClass = instanceClass;
423 assert(initMethod.isResolved());
424 }
425 @Override
426 MethodHandle viewAsType(MethodType newType) {
427 return new Constructor(newType, form, member, initMethod, instanceClass);
428 }
429 }
430
431 /*non-public*/ static Object constructorMethod(Object mh) {
432 Constructor dmh = (Constructor)mh;
433 return dmh.initMethod;
434 }
435
436 /*non-public*/ static Object allocateInstance(Object mh) throws InstantiationException {
437 Constructor dmh = (Constructor)mh;
438 return UNSAFE.allocateInstance(dmh.instanceClass);
439 }
440
441 /** This subclass handles non-static field references. */
442 static class Accessor extends DirectMethodHandle {
443 final Class<?> fieldType;
444 final int fieldOffset;
445 private Accessor(MethodType mtype, LambdaForm form, MemberName member,
446 int fieldOffset) {
447 super(mtype, form, member);
448 this.fieldType = member.getFieldType();
449 this.fieldOffset = fieldOffset;
450 }
451
452 @Override Object checkCast(Object obj) {
453 return fieldType.cast(obj);
454 }
455 @Override
456 MethodHandle viewAsType(MethodType newType) {
457 return new Accessor(newType, form, member, fieldOffset);
458 }
459 }
460
461 @ForceInline
462 /*non-public*/ static long fieldOffset(Object accessorObj) {
463 // Note: We return a long because that is what Unsafe.getObject likes.
464 // We store a plain int because it is more compact.
465 return ((Accessor)accessorObj).fieldOffset;
466 }
467
468 @ForceInline
469 /*non-public*/ static Object checkBase(Object obj) {
470 // Note that the object's class has already been verified,
471 // since the parameter type of the Accessor method handle
472 // is either member.getDeclaringClass or a subclass.
473 // This was verified in DirectMethodHandle.make.
474 // Therefore, the only remaining check is for null.
475 // Since this check is *not* guaranteed by Unsafe.getInt
476 // and its siblings, we need to make an explicit one here.
477 obj.getClass(); // maybe throw NPE
478 return obj;
479 }
480
481 /** This subclass handles static field references. */
482 static class StaticAccessor extends DirectMethodHandle {
483 final private Class<?> fieldType;
484 final private Object staticBase;
485 final private long staticOffset;
486
487 private StaticAccessor(MethodType mtype, LambdaForm form, MemberName member,
488 Object staticBase, long staticOffset) {
489 super(mtype, form, member);
490 this.fieldType = member.getFieldType();
491 this.staticBase = staticBase;
492 this.staticOffset = staticOffset;
493 }
494
495 @Override Object checkCast(Object obj) {
496 return fieldType.cast(obj);
497 }
498 @Override
499 MethodHandle viewAsType(MethodType newType) {
500 return new StaticAccessor(newType, form, member, staticBase, staticOffset);
501 }
502 }
503
504 @ForceInline
505 /*non-public*/ static Object nullCheck(Object obj) {
506 obj.getClass();
507 return obj;
508 }
509
510 @ForceInline
511 /*non-public*/ static Object staticBase(Object accessorObj) {
512 return ((StaticAccessor)accessorObj).staticBase;
513 }
514
515 @ForceInline
516 /*non-public*/ static long staticOffset(Object accessorObj) {
517 return ((StaticAccessor)accessorObj).staticOffset;
518 }
519
520 @ForceInline
521 /*non-public*/ static Object checkCast(Object mh, Object obj) {
522 return ((DirectMethodHandle) mh).checkCast(obj);
523 }
524
525 Object checkCast(Object obj) {
526 return member.getReturnType().cast(obj);
527 }
528
529 // Caching machinery for field accessors:
530 private static byte
531 AF_GETFIELD = 0,
532 AF_PUTFIELD = 1,
533 AF_GETSTATIC = 2,
534 AF_PUTSTATIC = 3,
535 AF_GETSTATIC_INIT = 4,
536 AF_PUTSTATIC_INIT = 5,
537 AF_LIMIT = 6;
538 // Enumerate the different field kinds using Wrapper,
539 // with an extra case added for checked references.
540 private static int
541 FT_LAST_WRAPPER = Wrapper.values().length-1,
542 FT_UNCHECKED_REF = Wrapper.OBJECT.ordinal(),
543 FT_CHECKED_REF = FT_LAST_WRAPPER+1,
544 FT_LIMIT = FT_LAST_WRAPPER+2;
545 private static int afIndex(byte formOp, boolean isVolatile, int ftypeKind) {
546 return ((formOp * FT_LIMIT * 2)
547 + (isVolatile ? FT_LIMIT : 0)
548 + ftypeKind);
549 }
550 private static final LambdaForm[] ACCESSOR_FORMS
551 = new LambdaForm[afIndex(AF_LIMIT, false, 0)];
552 private static int ftypeKind(Class<?> ftype) {
553 if (ftype.isPrimitive())
554 return Wrapper.forPrimitiveType(ftype).ordinal();
555 else if (VerifyType.isNullReferenceConversion(Object.class, ftype))
556 return FT_UNCHECKED_REF;
557 else
558 return FT_CHECKED_REF;
559 }
560
561 /**
562 * Create a LF which can access the given field.
563 * Cache and share this structure among all fields with
564 * the same basicType and refKind.
565 */
566 private static LambdaForm preparedFieldLambdaForm(MemberName m) {
567 Class<?> ftype = m.getFieldType();
568 boolean isVolatile = m.isVolatile();
569 byte formOp;
570 switch (m.getReferenceKind()) {
571 case REF_getField: formOp = AF_GETFIELD; break;
572 case REF_putField: formOp = AF_PUTFIELD; break;
573 case REF_getStatic: formOp = AF_GETSTATIC; break;
574 case REF_putStatic: formOp = AF_PUTSTATIC; break;
575 default: throw new InternalError(m.toString());
576 }
577 if (shouldBeInitialized(m)) {
578 // precompute the barrier-free version:
579 preparedFieldLambdaForm(formOp, isVolatile, ftype);
580 assert((AF_GETSTATIC_INIT - AF_GETSTATIC) ==
581 (AF_PUTSTATIC_INIT - AF_PUTSTATIC));
582 formOp += (AF_GETSTATIC_INIT - AF_GETSTATIC);
583 }
584 LambdaForm lform = preparedFieldLambdaForm(formOp, isVolatile, ftype);
585 maybeCompile(lform, m);
586 assert(lform.methodType().dropParameterTypes(0, 1)
587 .equals(m.getInvocationType().basicType()))
588 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
589 return lform;
590 }
591 private static LambdaForm preparedFieldLambdaForm(byte formOp, boolean isVolatile, Class<?> ftype) {
592 int afIndex = afIndex(formOp, isVolatile, ftypeKind(ftype));
593 LambdaForm lform = ACCESSOR_FORMS[afIndex];
594 if (lform != null) return lform;
595 lform = makePreparedFieldLambdaForm(formOp, isVolatile, ftypeKind(ftype));
596 ACCESSOR_FORMS[afIndex] = lform; // don't bother with a CAS
597 return lform;
598 }
599
600 private static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, int ftypeKind) {
601 boolean isGetter = (formOp & 1) == (AF_GETFIELD & 1);
602 boolean isStatic = (formOp >= AF_GETSTATIC);
603 boolean needsInit = (formOp >= AF_GETSTATIC_INIT);
604 boolean needsCast = (ftypeKind == FT_CHECKED_REF);
605 Wrapper fw = (needsCast ? Wrapper.OBJECT : Wrapper.values()[ftypeKind]);
606 Class<?> ft = fw.primitiveType();
607 assert(ftypeKind(needsCast ? String.class : ft) == ftypeKind);
608 String tname = fw.primitiveSimpleName();
609 String ctname = Character.toUpperCase(tname.charAt(0)) + tname.substring(1);
610 if (isVolatile) ctname += "Volatile";
611 String getOrPut = (isGetter ? "get" : "put");
612 String linkerName = (getOrPut + ctname); // getObject, putIntVolatile, etc.
613 MethodType linkerType;
614 if (isGetter)
615 linkerType = MethodType.methodType(ft, Object.class, long.class);
616 else
617 linkerType = MethodType.methodType(void.class, Object.class, long.class, ft);
618 MemberName linker = new MemberName(Unsafe.class, linkerName, linkerType, REF_invokeVirtual);
619 try {
620 linker = IMPL_NAMES.resolveOrFail(REF_invokeVirtual, linker, null, NoSuchMethodException.class);
621 } catch (ReflectiveOperationException ex) {
622 throw newInternalError(ex);
623 }
624
625 // What is the external type of the lambda form?
626 MethodType mtype;
627 if (isGetter)
628 mtype = MethodType.methodType(ft);
629 else
630 mtype = MethodType.methodType(void.class, ft);
631 mtype = mtype.basicType(); // erase short to int, etc.
632 if (!isStatic)
633 mtype = mtype.insertParameterTypes(0, Object.class);
634 final int DMH_THIS = 0;
635 final int ARG_BASE = 1;
636 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
637 // if this is for non-static access, the base pointer is stored at this index:
638 final int OBJ_BASE = isStatic ? -1 : ARG_BASE;
639 // if this is for write access, the value to be written is stored at this index:
640 final int SET_VALUE = isGetter ? -1 : ARG_LIMIT - 1;
641 int nameCursor = ARG_LIMIT;
642 final int F_HOLDER = (isStatic ? nameCursor++ : -1); // static base if any
643 final int F_OFFSET = nameCursor++; // Either static offset or field offset.
644 final int OBJ_CHECK = (OBJ_BASE >= 0 ? nameCursor++ : -1);
645 final int INIT_BAR = (needsInit ? nameCursor++ : -1);
646 final int PRE_CAST = (needsCast && !isGetter ? nameCursor++ : -1);
647 final int LINKER_CALL = nameCursor++;
648 final int POST_CAST = (needsCast && isGetter ? nameCursor++ : -1);
649 final int RESULT = nameCursor-1; // either the call or the cast
650 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
651 if (needsInit)
652 names[INIT_BAR] = new Name(Lazy.NF_ensureInitialized, names[DMH_THIS]);
653 if (needsCast && !isGetter)
654 names[PRE_CAST] = new Name(Lazy.NF_checkCast, names[DMH_THIS], names[SET_VALUE]);
655 Object[] outArgs = new Object[1 + linkerType.parameterCount()];
656 assert(outArgs.length == (isGetter ? 3 : 4));
657 outArgs[0] = UNSAFE;
658 if (isStatic) {
659 outArgs[1] = names[F_HOLDER] = new Name(Lazy.NF_staticBase, names[DMH_THIS]);
660 outArgs[2] = names[F_OFFSET] = new Name(Lazy.NF_staticOffset, names[DMH_THIS]);
661 } else {
662 outArgs[1] = names[OBJ_CHECK] = new Name(Lazy.NF_checkBase, names[OBJ_BASE]);
663 outArgs[2] = names[F_OFFSET] = new Name(Lazy.NF_fieldOffset, names[DMH_THIS]);
664 }
665 if (!isGetter) {
666 outArgs[3] = (needsCast ? names[PRE_CAST] : names[SET_VALUE]);
667 }
668 for (Object a : outArgs) assert(a != null);
669 names[LINKER_CALL] = new Name(linker, outArgs);
670 if (needsCast && isGetter)
671 names[POST_CAST] = new Name(Lazy.NF_checkCast, names[DMH_THIS], names[LINKER_CALL]);
672 for (Name n : names) assert(n != null);
673 String fieldOrStatic = (isStatic ? "Static" : "Field");
674 String lambdaName = (linkerName + fieldOrStatic); // significant only for debugging
675 if (needsCast) lambdaName += "Cast";
676 if (needsInit) lambdaName += "Init";
677 return new LambdaForm(lambdaName, ARG_LIMIT, names, RESULT);
678 }
679
680 /**
681 * Pre-initialized NamedFunctions for bootstrapping purposes.
682 * Factored in an inner class to delay initialization until first usage.
683 */
684 private static class Lazy {
685 static final NamedFunction
686 NF_internalMemberName,
687 NF_internalMemberNameEnsureInit,
688 NF_ensureInitialized,
689 NF_fieldOffset,
690 NF_checkBase,
691 NF_staticBase,
692 NF_staticOffset,
693 NF_checkCast,
694 NF_allocateInstance,
695 NF_constructorMethod;
696 static {
697 try {
698 NamedFunction nfs[] = {
699 NF_internalMemberName = new NamedFunction(DirectMethodHandle.class
700 .getDeclaredMethod("internalMemberName", Object.class)),
701 NF_internalMemberNameEnsureInit = new NamedFunction(DirectMethodHandle.class
702 .getDeclaredMethod("internalMemberNameEnsureInit", Object.class)),
703 NF_ensureInitialized = new NamedFunction(DirectMethodHandle.class
704 .getDeclaredMethod("ensureInitialized", Object.class)),
705 NF_fieldOffset = new NamedFunction(DirectMethodHandle.class
706 .getDeclaredMethod("fieldOffset", Object.class)),
707 NF_checkBase = new NamedFunction(DirectMethodHandle.class
708 .getDeclaredMethod("checkBase", Object.class)),
709 NF_staticBase = new NamedFunction(DirectMethodHandle.class
710 .getDeclaredMethod("staticBase", Object.class)),
711 NF_staticOffset = new NamedFunction(DirectMethodHandle.class
712 .getDeclaredMethod("staticOffset", Object.class)),
713 NF_checkCast = new NamedFunction(DirectMethodHandle.class
714 .getDeclaredMethod("checkCast", Object.class, Object.class)),
715 NF_allocateInstance = new NamedFunction(DirectMethodHandle.class
716 .getDeclaredMethod("allocateInstance", Object.class)),
717 NF_constructorMethod = new NamedFunction(DirectMethodHandle.class
718 .getDeclaredMethod("constructorMethod", Object.class))
719 };
720 for (NamedFunction nf : nfs) {
721 // Each nf must be statically invocable or we get tied up in our bootstraps.
722 assert(InvokerBytecodeGenerator.isStaticallyInvocable(nf.member)) : nf;
723 nf.resolve();
724 }
725 } catch (ReflectiveOperationException ex) {
726 throw newInternalError(ex);
727 }
728 }
729 }
730 }