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