1 /*
2 * Copyright (c) 2008, 2018, 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.misc.Unsafe;
29 import jdk.internal.vm.annotation.ForceInline;
30 import jdk.internal.vm.annotation.Stable;
31 import sun.invoke.util.ValueConversions;
32 import sun.invoke.util.VerifyAccess;
33 import sun.invoke.util.VerifyType;
34 import sun.invoke.util.Wrapper;
35
36 import java.lang.ref.WeakReference;
37 import java.util.Arrays;
38 import java.util.Objects;
39
40 import static java.lang.invoke.LambdaForm.*;
41 import static java.lang.invoke.LambdaForm.Kind.*;
42 import static java.lang.invoke.MethodHandleNatives.Constants.*;
43 import static java.lang.invoke.MethodHandleStatics.UNSAFE;
44 import static java.lang.invoke.MethodHandleStatics.newInternalError;
45 import static java.lang.invoke.MethodTypeForm.*;
46
47 /**
48 * The flavor of method handle which implements a constant reference
49 * to a class member.
50 * @author jrose
51 */
52 class DirectMethodHandle extends MethodHandle {
53 final MemberName member;
54 final boolean crackable;
55
56 // Constructors and factory methods in this class *must* be package scoped or private.
57 private DirectMethodHandle(MethodType mtype, LambdaForm form, MemberName member, boolean crackable) {
58 super(mtype, form);
59 if (!member.isResolved()) throw new InternalError();
60
61 if (member.getDeclaringClass().isInterface() &&
62 member.getReferenceKind() == REF_invokeInterface &&
63 member.isMethod() && !member.isAbstract()) {
64 // Check for corner case: invokeinterface of Object method
65 MemberName m = new MemberName(Object.class, member.getName(), member.getMethodType(), member.getReferenceKind());
66 m = MemberName.getFactory().resolveOrNull(m.getReferenceKind(), m, null);
67 if (m != null && m.isPublic()) {
68 assert(member.getReferenceKind() == m.getReferenceKind()); // else this.form is wrong
69 member = m;
70 }
71 }
72
73 this.member = member;
74 this.crackable = crackable;
75 }
76
77 // Factory methods:
78 static DirectMethodHandle make(byte refKind, Class<?> refc, MemberName member, Class<?> callerClass) {
79 MethodType mtype = member.getMethodOrFieldType();
80 if (!member.isStatic()) {
81 if (!member.getDeclaringClass().isAssignableFrom(refc) || member.isConstructor())
82 throw new InternalError(member.toString());
83 mtype = mtype.insertParameterTypes(0, refc);
84 }
85 if (!member.isField()) {
86 // refKind reflects the original type of lookup via findSpecial or
87 // findVirtual etc.
88 switch (refKind) {
89 case REF_invokeSpecial: {
90 member = member.asSpecial();
91 // if caller is an interface we need to adapt to get the
92 // receiver check inserted
93 if (callerClass == null) {
94 throw new InternalError("callerClass must not be null for REF_invokeSpecial");
95 }
96 LambdaForm lform = preparedLambdaForm(member, callerClass.isInterface());
97 return new Special(mtype, lform, member, true, callerClass);
98 }
99 case REF_invokeInterface: {
100 // for interfaces we always need the receiver typecheck,
101 // so we always pass 'true' to ensure we adapt if needed
102 // to include the REF_invokeSpecial case
103 LambdaForm lform = preparedLambdaForm(member, true);
104 return new Interface(mtype, lform, member, true, refc);
105 }
106 default: {
107 LambdaForm lform = preparedLambdaForm(member);
108 return new DirectMethodHandle(mtype, lform, member, true);
109 }
110 }
111 } else {
112 LambdaForm lform = preparedFieldLambdaForm(member);
113 if (member.isStatic()) {
114 long offset = MethodHandleNatives.staticFieldOffset(member);
115 Object base = MethodHandleNatives.staticFieldBase(member);
116 return new StaticAccessor(mtype, lform, member, true, base, offset);
117 } else {
118 long offset = MethodHandleNatives.objectFieldOffset(member);
119 assert(offset == (int)offset);
120 return new Accessor(mtype, lform, member, true, (int)offset);
121 }
122 }
123 }
124 static DirectMethodHandle make(Class<?> refc, MemberName member) {
125 byte refKind = member.getReferenceKind();
126 if (refKind == REF_invokeSpecial)
127 refKind = REF_invokeVirtual;
128 return make(refKind, refc, member, null /* no callerClass context */);
129 }
130 static DirectMethodHandle make(MemberName member) {
131 if (member.isConstructor())
132 return makeAllocator(member);
133 return make(member.getDeclaringClass(), member);
134 }
135 private static DirectMethodHandle makeAllocator(MemberName ctor) {
136 assert(ctor.isConstructor() && ctor.getName().equals("<init>"));
137 Class<?> instanceClass = ctor.getDeclaringClass();
138 ctor = ctor.asConstructor();
139 assert(ctor.isConstructor() && ctor.getReferenceKind() == REF_newInvokeSpecial) : ctor;
140 MethodType mtype = ctor.getMethodType().changeReturnType(instanceClass);
141 LambdaForm lform = preparedLambdaForm(ctor);
142 MemberName init = ctor.asSpecial();
143 assert(init.getMethodType().returnType() == void.class);
144 return new Constructor(mtype, lform, ctor, true, init, instanceClass);
145 }
146
147 @Override
148 BoundMethodHandle rebind() {
149 return BoundMethodHandle.makeReinvoker(this);
150 }
151
152 @Override
153 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
154 assert(this.getClass() == DirectMethodHandle.class); // must override in subclasses
155 return new DirectMethodHandle(mt, lf, member, crackable);
156 }
157 /*non-public*/
158 @Override
159 MethodHandle viewAsType(MethodType newType, boolean strict) {
160 // No actual conversions, just a new view of the same method.
161 // However, we must not expose a DMH that is crackable into a
162 // MethodHandleInfo, so we return a cloned, uncrackable DMH
163 assert viewAsTypeChecks(newType, strict);
164 assert(this.getClass() == DirectMethodHandle.class); // must override in subclasses
165 return new DirectMethodHandle(newType, form, member, false);
166 }
167 /*non-public*/
168 @Override
169 boolean isCrackable() {
170 return crackable;
171 }
172
173
174 @Override
175 String internalProperties() {
176 return "\n& DMH.MN="+internalMemberName();
177 }
178
179 //// Implementation methods.
180 @Override
181 @ForceInline
182 MemberName internalMemberName() {
183 return member;
184 }
185
186 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
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, boolean adaptToSpecialIfc) {
194 assert(m.isInvocable()) : m; // call preparedFieldLambdaForm instead
195 MethodType mtype = m.getInvocationType().basicType();
196 assert(!m.isMethodHandleInvoke()) : m;
197 int which;
198 // MemberName.getReferenceKind represents the JVM optimized form of the call
199 // as distinct from the "kind" passed to DMH.make which represents the original
200 // bytecode-equivalent request. Specifically private/final methods that use a direct
201 // call have getReferenceKind adapted to REF_invokeSpecial, even though the actual
202 // invocation mode may be invokevirtual or invokeinterface.
203 switch (m.getReferenceKind()) {
204 case REF_invokeVirtual: which = LF_INVVIRTUAL; break;
205 case REF_invokeStatic: which = LF_INVSTATIC; break;
206 case REF_invokeSpecial: which = LF_INVSPECIAL; break;
207 case REF_invokeInterface: which = LF_INVINTERFACE; break;
208 case REF_newInvokeSpecial: which = LF_NEWINVSPECIAL; break;
209 default: throw new InternalError(m.toString());
210 }
211 if (which == LF_INVSTATIC && shouldBeInitialized(m)) {
212 // precompute the barrier-free version:
213 preparedLambdaForm(mtype, which);
214 which = LF_INVSTATIC_INIT;
215 }
216 if (which == LF_INVSPECIAL && adaptToSpecialIfc) {
217 which = LF_INVSPECIAL_IFC;
218 }
219 LambdaForm lform = preparedLambdaForm(mtype, which);
220 maybeCompile(lform, m);
221 assert(lform.methodType().dropParameterTypes(0, 1)
222 .equals(m.getInvocationType().basicType()))
223 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
224 return lform;
225 }
226
227 private static LambdaForm preparedLambdaForm(MemberName m) {
228 return preparedLambdaForm(m, false);
229 }
230
231 private static LambdaForm preparedLambdaForm(MethodType mtype, int which) {
232 LambdaForm lform = mtype.form().cachedLambdaForm(which);
233 if (lform != null) return lform;
234 lform = makePreparedLambdaForm(mtype, which);
235 return mtype.form().setCachedLambdaForm(which, lform);
236 }
237
238 static LambdaForm makePreparedLambdaForm(MethodType mtype, int which) {
239 boolean needsInit = (which == LF_INVSTATIC_INIT);
240 boolean doesAlloc = (which == LF_NEWINVSPECIAL);
241 boolean needsReceiverCheck = (which == LF_INVINTERFACE ||
242 which == LF_INVSPECIAL_IFC);
243
244 String linkerName;
245 LambdaForm.Kind kind;
246 switch (which) {
247 case LF_INVVIRTUAL: linkerName = "linkToVirtual"; kind = DIRECT_INVOKE_VIRTUAL; break;
248 case LF_INVSTATIC: linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC; break;
249 case LF_INVSTATIC_INIT:linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC_INIT; break;
250 case LF_INVSPECIAL_IFC:linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL_IFC; break;
251 case LF_INVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL; break;
252 case LF_INVINTERFACE: linkerName = "linkToInterface"; kind = DIRECT_INVOKE_INTERFACE; break;
253 case LF_NEWINVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_NEW_INVOKE_SPECIAL; break;
254 default: throw new InternalError("which="+which);
255 }
256
257 MethodType mtypeWithArg = mtype.appendParameterTypes(MemberName.class);
258 if (doesAlloc)
259 mtypeWithArg = mtypeWithArg
260 .insertParameterTypes(0, Object.class) // insert newly allocated obj
261 .changeReturnType(void.class); // <init> returns void
262 MemberName linker = new MemberName(MethodHandle.class, linkerName, mtypeWithArg, REF_invokeStatic);
263 try {
264 linker = IMPL_NAMES.resolveOrFail(REF_invokeStatic, linker, null, NoSuchMethodException.class);
265 } catch (ReflectiveOperationException ex) {
266 throw newInternalError(ex);
267 }
268 final int DMH_THIS = 0;
269 final int ARG_BASE = 1;
270 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
271 int nameCursor = ARG_LIMIT;
272 final int NEW_OBJ = (doesAlloc ? nameCursor++ : -1);
273 final int GET_MEMBER = nameCursor++;
274 final int CHECK_RECEIVER = (needsReceiverCheck ? nameCursor++ : -1);
275 final int LINKER_CALL = nameCursor++;
276 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
277 assert(names.length == nameCursor);
278 if (doesAlloc) {
279 // names = { argx,y,z,... new C, init method }
280 names[NEW_OBJ] = new Name(getFunction(NF_allocateInstance), names[DMH_THIS]);
281 names[GET_MEMBER] = new Name(getFunction(NF_constructorMethod), names[DMH_THIS]);
282 } else if (needsInit) {
283 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberNameEnsureInit), names[DMH_THIS]);
284 } else {
285 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberName), names[DMH_THIS]);
286 }
287 assert(findDirectMethodHandle(names[GET_MEMBER]) == names[DMH_THIS]);
288 Object[] outArgs = Arrays.copyOfRange(names, ARG_BASE, GET_MEMBER+1, Object[].class);
289 if (needsReceiverCheck) {
290 names[CHECK_RECEIVER] = new Name(getFunction(NF_checkReceiver), names[DMH_THIS], names[ARG_BASE]);
291 outArgs[0] = names[CHECK_RECEIVER];
292 }
293 assert(outArgs[outArgs.length-1] == names[GET_MEMBER]); // look, shifted args!
294 int result = LAST_RESULT;
295 if (doesAlloc) {
296 assert(outArgs[outArgs.length-2] == names[NEW_OBJ]); // got to move this one
297 System.arraycopy(outArgs, 0, outArgs, 1, outArgs.length-2);
298 outArgs[0] = names[NEW_OBJ];
299 result = NEW_OBJ;
300 }
301 names[LINKER_CALL] = new Name(linker, outArgs);
302 LambdaForm lform = new LambdaForm(ARG_LIMIT, names, result, kind);
303
304 // This is a tricky bit of code. Don't send it through the LF interpreter.
305 lform.compileToBytecode();
306 return lform;
307 }
308
309 /* assert */ static Object findDirectMethodHandle(Name name) {
310 if (name.function.equals(getFunction(NF_internalMemberName)) ||
311 name.function.equals(getFunction(NF_internalMemberNameEnsureInit)) ||
312 name.function.equals(getFunction(NF_constructorMethod))) {
313 assert(name.arguments.length == 1);
314 return name.arguments[0];
315 }
316 return null;
317 }
318
319 private static void maybeCompile(LambdaForm lform, MemberName m) {
320 if (lform.vmentry == null && VerifyAccess.isSamePackage(m.getDeclaringClass(), MethodHandle.class))
321 // Help along bootstrapping...
322 lform.compileToBytecode();
323 }
324
325 /** Static wrapper for DirectMethodHandle.internalMemberName. */
326 @ForceInline
327 /*non-public*/
328 static Object internalMemberName(Object mh) {
329 return ((DirectMethodHandle)mh).member;
330 }
331
332 /** Static wrapper for DirectMethodHandle.internalMemberName.
333 * This one also forces initialization.
334 */
335 /*non-public*/
336 static Object internalMemberNameEnsureInit(Object mh) {
337 DirectMethodHandle dmh = (DirectMethodHandle)mh;
338 dmh.ensureInitialized();
339 return dmh.member;
340 }
341
342 /*non-public*/
343 static boolean shouldBeInitialized(MemberName member) {
344 switch (member.getReferenceKind()) {
345 case REF_invokeStatic:
346 case REF_getStatic:
347 case REF_putStatic:
348 case REF_newInvokeSpecial:
349 break;
350 default:
351 // No need to initialize the class on this kind of member.
352 return false;
353 }
354 Class<?> cls = member.getDeclaringClass();
355 if (cls == ValueConversions.class ||
356 cls == MethodHandleImpl.class ||
357 cls == Invokers.class) {
358 // These guys have lots of <clinit> DMH creation but we know
359 // the MHs will not be used until the system is booted.
360 return false;
361 }
362 if (VerifyAccess.isSamePackage(MethodHandle.class, cls) ||
363 VerifyAccess.isSamePackage(ValueConversions.class, cls)) {
364 // It is a system class. It is probably in the process of
365 // being initialized, but we will help it along just to be safe.
366 if (UNSAFE.shouldBeInitialized(cls)) {
367 UNSAFE.ensureClassInitialized(cls);
368 }
369 return false;
370 }
371 return UNSAFE.shouldBeInitialized(cls);
372 }
373
374 private static class EnsureInitialized extends ClassValue<WeakReference<Thread>> {
375 @Override
376 protected WeakReference<Thread> computeValue(Class<?> type) {
377 UNSAFE.ensureClassInitialized(type);
378 if (UNSAFE.shouldBeInitialized(type))
379 // If the previous call didn't block, this can happen.
380 // We are executing inside <clinit>.
381 return new WeakReference<>(Thread.currentThread());
382 return null;
383 }
384 static final EnsureInitialized INSTANCE = new EnsureInitialized();
385 }
386
387 private void ensureInitialized() {
388 if (checkInitialized(member)) {
389 // The coast is clear. Delete the <clinit> barrier.
390 if (member.isField())
391 updateForm(preparedFieldLambdaForm(member));
392 else
393 updateForm(preparedLambdaForm(member));
394 }
395 }
396 private static boolean checkInitialized(MemberName member) {
397 Class<?> defc = member.getDeclaringClass();
398 WeakReference<Thread> ref = EnsureInitialized.INSTANCE.get(defc);
399 if (ref == null) {
400 return true; // the final state
401 }
402 Thread clinitThread = ref.get();
403 // Somebody may still be running defc.<clinit>.
404 if (clinitThread == Thread.currentThread()) {
405 // If anybody is running defc.<clinit>, it is this thread.
406 if (UNSAFE.shouldBeInitialized(defc))
407 // Yes, we are running it; keep the barrier for now.
408 return false;
409 } else {
410 // We are in a random thread. Block.
411 UNSAFE.ensureClassInitialized(defc);
412 }
413 assert(!UNSAFE.shouldBeInitialized(defc));
414 // put it into the final state
415 EnsureInitialized.INSTANCE.remove(defc);
416 return true;
417 }
418
419 /*non-public*/
420 static void ensureInitialized(Object mh) {
421 ((DirectMethodHandle)mh).ensureInitialized();
422 }
423
424 /** This subclass represents invokespecial instructions. */
425 static class Special extends DirectMethodHandle {
426 private final Class<?> caller;
427 private Special(MethodType mtype, LambdaForm form, MemberName member, boolean crackable, Class<?> caller) {
428 super(mtype, form, member, crackable);
429 this.caller = caller;
430 }
431 @Override
432 boolean isInvokeSpecial() {
433 return true;
434 }
435 @Override
436 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
437 return new Special(mt, lf, member, crackable, caller);
438 }
439 @Override
440 MethodHandle viewAsType(MethodType newType, boolean strict) {
441 assert viewAsTypeChecks(newType, strict);
442 return new Special(newType, form, member, false, caller);
443 }
444 Object checkReceiver(Object recv) {
445 if (!caller.isInstance(recv)) {
446 String msg = String.format("Receiver class %s is not a subclass of caller class %s",
447 recv.getClass().getName(), caller.getName());
448 throw new IncompatibleClassChangeError(msg);
449 }
450 return recv;
451 }
452 }
453
454 /** This subclass represents invokeinterface instructions. */
455 static class Interface extends DirectMethodHandle {
456 private final Class<?> refc;
457 private Interface(MethodType mtype, LambdaForm form, MemberName member, boolean crackable, Class<?> refc) {
458 super(mtype, form, member, crackable);
459 assert refc.isInterface() : refc;
460 this.refc = refc;
461 }
462 @Override
463 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
464 return new Interface(mt, lf, member, crackable, refc);
465 }
466 @Override
467 MethodHandle viewAsType(MethodType newType, boolean strict) {
468 assert viewAsTypeChecks(newType, strict);
469 return new Interface(newType, form, member, false, refc);
470 }
471 @Override
472 Object checkReceiver(Object recv) {
473 if (!refc.isInstance(recv)) {
474 String msg = String.format("Receiver class %s does not implement the requested interface %s",
475 recv.getClass().getName(), refc.getName());
476 throw new IncompatibleClassChangeError(msg);
477 }
478 return recv;
479 }
480 }
481
482 /** Used for interface receiver type checks, by Interface and Special modes. */
483 Object checkReceiver(Object recv) {
484 throw new InternalError("Should only be invoked on a subclass");
485 }
486
487
488 /** This subclass handles constructor references. */
489 static class Constructor extends DirectMethodHandle {
490 final MemberName initMethod;
491 final Class<?> instanceClass;
492
493 private Constructor(MethodType mtype, LambdaForm form, MemberName constructor,
494 boolean crackable, MemberName initMethod, Class<?> instanceClass) {
495 super(mtype, form, constructor, crackable);
496 this.initMethod = initMethod;
497 this.instanceClass = instanceClass;
498 assert(initMethod.isResolved());
499 }
500 @Override
501 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
502 return new Constructor(mt, lf, member, crackable, initMethod, instanceClass);
503 }
504 @Override
505 MethodHandle viewAsType(MethodType newType, boolean strict) {
506 assert viewAsTypeChecks(newType, strict);
507 return new Constructor(newType, form, member, false, initMethod, instanceClass);
508 }
509 }
510
511 /*non-public*/
512 static Object constructorMethod(Object mh) {
513 Constructor dmh = (Constructor)mh;
514 return dmh.initMethod;
515 }
516
517 /*non-public*/
518 static Object allocateInstance(Object mh) throws InstantiationException {
519 Constructor dmh = (Constructor)mh;
520 return UNSAFE.allocateInstance(dmh.instanceClass);
521 }
522
523 /** This subclass handles non-static field references. */
524 static class Accessor extends DirectMethodHandle {
525 final Class<?> fieldType;
526 final int fieldOffset;
527 private Accessor(MethodType mtype, LambdaForm form, MemberName member,
528 boolean crackable, int fieldOffset) {
529 super(mtype, form, member, crackable);
530 this.fieldType = member.getFieldType();
531 this.fieldOffset = fieldOffset;
532 }
533
534 @Override Object checkCast(Object obj) {
535 return fieldType.cast(obj);
536 }
537 @Override
538 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
539 return new Accessor(mt, lf, member, crackable, fieldOffset);
540 }
541 @Override
542 MethodHandle viewAsType(MethodType newType, boolean strict) {
543 assert viewAsTypeChecks(newType, strict);
544 return new Accessor(newType, form, member, false, fieldOffset);
545 }
546 }
547
548 @ForceInline
549 /*non-public*/
550 static long fieldOffset(Object accessorObj) {
551 // Note: We return a long because that is what Unsafe.getObject likes.
552 // We store a plain int because it is more compact.
553 return ((Accessor)accessorObj).fieldOffset;
554 }
555
556 @ForceInline
557 /*non-public*/
558 static Object checkBase(Object obj) {
559 // Note that the object's class has already been verified,
560 // since the parameter type of the Accessor method handle
561 // is either member.getDeclaringClass or a subclass.
562 // This was verified in DirectMethodHandle.make.
563 // Therefore, the only remaining check is for null.
564 // Since this check is *not* guaranteed by Unsafe.getInt
565 // and its siblings, we need to make an explicit one here.
566 return Objects.requireNonNull(obj);
567 }
568
569 /** This subclass handles static field references. */
570 static class StaticAccessor extends DirectMethodHandle {
571 private final Class<?> fieldType;
572 private final Object staticBase;
573 private final long staticOffset;
574
575 private StaticAccessor(MethodType mtype, LambdaForm form, MemberName member,
576 boolean crackable, Object staticBase, long staticOffset) {
577 super(mtype, form, member, crackable);
578 this.fieldType = member.getFieldType();
579 this.staticBase = staticBase;
580 this.staticOffset = staticOffset;
581 }
582
583 @Override Object checkCast(Object obj) {
584 return fieldType.cast(obj);
585 }
586 @Override
587 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
588 return new StaticAccessor(mt, lf, member, crackable, staticBase, staticOffset);
589 }
590 @Override
591 MethodHandle viewAsType(MethodType newType, boolean strict) {
592 assert viewAsTypeChecks(newType, strict);
593 return new StaticAccessor(newType, form, member, false, staticBase, staticOffset);
594 }
595 }
596
597 @ForceInline
598 /*non-public*/
599 static Object nullCheck(Object obj) {
600 return Objects.requireNonNull(obj);
601 }
602
603 @ForceInline
604 /*non-public*/
605 static Object staticBase(Object accessorObj) {
606 return ((StaticAccessor)accessorObj).staticBase;
607 }
608
609 @ForceInline
610 /*non-public*/
611 static long staticOffset(Object accessorObj) {
612 return ((StaticAccessor)accessorObj).staticOffset;
613 }
614
615 @ForceInline
616 /*non-public*/
617 static Object checkCast(Object mh, Object obj) {
618 return ((DirectMethodHandle) mh).checkCast(obj);
619 }
620
621 Object checkCast(Object obj) {
622 return member.getReturnType().cast(obj);
623 }
624
625 // Caching machinery for field accessors:
626 static final byte
627 AF_GETFIELD = 0,
628 AF_PUTFIELD = 1,
629 AF_GETSTATIC = 2,
630 AF_PUTSTATIC = 3,
631 AF_GETSTATIC_INIT = 4,
632 AF_PUTSTATIC_INIT = 5,
633 AF_LIMIT = 6;
634 // Enumerate the different field kinds using Wrapper,
635 // with an extra case added for checked references.
636 static final int
637 FT_LAST_WRAPPER = Wrapper.COUNT-1,
638 FT_UNCHECKED_REF = Wrapper.OBJECT.ordinal(),
639 FT_CHECKED_REF = FT_LAST_WRAPPER+1,
640 FT_LIMIT = FT_LAST_WRAPPER+2;
641 private static int afIndex(byte formOp, boolean isVolatile, int ftypeKind) {
642 return ((formOp * FT_LIMIT * 2)
643 + (isVolatile ? FT_LIMIT : 0)
644 + ftypeKind);
645 }
646 @Stable
647 private static final LambdaForm[] ACCESSOR_FORMS
648 = new LambdaForm[afIndex(AF_LIMIT, false, 0)];
649 static int ftypeKind(Class<?> ftype) {
650 if (ftype.isPrimitive())
651 return Wrapper.forPrimitiveType(ftype).ordinal();
652 else if (VerifyType.isNullReferenceConversion(Object.class, ftype))
653 return FT_UNCHECKED_REF;
654 else
655 return FT_CHECKED_REF;
656 }
657
658 /**
659 * Create a LF which can access the given field.
660 * Cache and share this structure among all fields with
661 * the same basicType and refKind.
662 */
663 private static LambdaForm preparedFieldLambdaForm(MemberName m) {
664 Class<?> ftype = m.getFieldType();
665 boolean isVolatile = m.isVolatile();
666 byte formOp;
667 switch (m.getReferenceKind()) {
668 case REF_getField: formOp = AF_GETFIELD; break;
669 case REF_putField: formOp = AF_PUTFIELD; break;
670 case REF_getStatic: formOp = AF_GETSTATIC; break;
671 case REF_putStatic: formOp = AF_PUTSTATIC; break;
672 default: throw new InternalError(m.toString());
673 }
674 if (shouldBeInitialized(m)) {
675 // precompute the barrier-free version:
676 preparedFieldLambdaForm(formOp, isVolatile, ftype);
677 assert((AF_GETSTATIC_INIT - AF_GETSTATIC) ==
678 (AF_PUTSTATIC_INIT - AF_PUTSTATIC));
679 formOp += (AF_GETSTATIC_INIT - AF_GETSTATIC);
680 }
681 LambdaForm lform = preparedFieldLambdaForm(formOp, isVolatile, ftype);
682 maybeCompile(lform, m);
683 assert(lform.methodType().dropParameterTypes(0, 1)
684 .equals(m.getInvocationType().basicType()))
685 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
686 return lform;
687 }
688 private static LambdaForm preparedFieldLambdaForm(byte formOp, boolean isVolatile, Class<?> ftype) {
689 int ftypeKind = ftypeKind(ftype);
690 int afIndex = afIndex(formOp, isVolatile, ftypeKind);
691 LambdaForm lform = ACCESSOR_FORMS[afIndex];
692 if (lform != null) return lform;
693 lform = makePreparedFieldLambdaForm(formOp, isVolatile, ftypeKind);
694 ACCESSOR_FORMS[afIndex] = lform; // don't bother with a CAS
695 return lform;
696 }
697
698 private static final Wrapper[] ALL_WRAPPERS = Wrapper.values();
699
700 private static Kind getFieldKind(boolean isGetter, boolean isVolatile, Wrapper wrapper) {
701 if (isGetter) {
702 if (isVolatile) {
703 switch (wrapper) {
704 case BOOLEAN: return GET_BOOLEAN_VOLATILE;
705 case BYTE: return GET_BYTE_VOLATILE;
706 case SHORT: return GET_SHORT_VOLATILE;
707 case CHAR: return GET_CHAR_VOLATILE;
708 case INT: return GET_INT_VOLATILE;
709 case LONG: return GET_LONG_VOLATILE;
710 case FLOAT: return GET_FLOAT_VOLATILE;
711 case DOUBLE: return GET_DOUBLE_VOLATILE;
712 case OBJECT: return GET_REFERENCE_VOLATILE;
713 }
714 } else {
715 switch (wrapper) {
716 case BOOLEAN: return GET_BOOLEAN;
717 case BYTE: return GET_BYTE;
718 case SHORT: return GET_SHORT;
719 case CHAR: return GET_CHAR;
720 case INT: return GET_INT;
721 case LONG: return GET_LONG;
722 case FLOAT: return GET_FLOAT;
723 case DOUBLE: return GET_DOUBLE;
724 case OBJECT: return GET_REFERENCE;
725 }
726 }
727 } else {
728 if (isVolatile) {
729 switch (wrapper) {
730 case BOOLEAN: return PUT_BOOLEAN_VOLATILE;
731 case BYTE: return PUT_BYTE_VOLATILE;
732 case SHORT: return PUT_SHORT_VOLATILE;
733 case CHAR: return PUT_CHAR_VOLATILE;
734 case INT: return PUT_INT_VOLATILE;
735 case LONG: return PUT_LONG_VOLATILE;
736 case FLOAT: return PUT_FLOAT_VOLATILE;
737 case DOUBLE: return PUT_DOUBLE_VOLATILE;
738 case OBJECT: return PUT_REFERENCE_VOLATILE;
739 }
740 } else {
741 switch (wrapper) {
742 case BOOLEAN: return PUT_BOOLEAN;
743 case BYTE: return PUT_BYTE;
744 case SHORT: return PUT_SHORT;
745 case CHAR: return PUT_CHAR;
746 case INT: return PUT_INT;
747 case LONG: return PUT_LONG;
748 case FLOAT: return PUT_FLOAT;
749 case DOUBLE: return PUT_DOUBLE;
750 case OBJECT: return PUT_REFERENCE;
751 }
752 }
753 }
754 throw new AssertionError("Invalid arguments");
755 }
756
757 static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, int ftypeKind) {
758 boolean isGetter = (formOp & 1) == (AF_GETFIELD & 1);
759 boolean isStatic = (formOp >= AF_GETSTATIC);
760 boolean needsInit = (formOp >= AF_GETSTATIC_INIT);
761 boolean needsCast = (ftypeKind == FT_CHECKED_REF);
762 Wrapper fw = (needsCast ? Wrapper.OBJECT : ALL_WRAPPERS[ftypeKind]);
763 Class<?> ft = fw.primitiveType();
764 assert(ftypeKind(needsCast ? String.class : ft) == ftypeKind);
765
766 // getObject, putIntVolatile, etc.
767 Kind kind = getFieldKind(isGetter, isVolatile, fw);
768
769 MethodType linkerType;
770 if (isGetter)
771 linkerType = MethodType.methodType(ft, Object.class, long.class);
772 else
773 linkerType = MethodType.methodType(void.class, Object.class, long.class, ft);
774 MemberName linker = new MemberName(Unsafe.class, kind.methodName, linkerType, REF_invokeVirtual);
775 try {
776 linker = IMPL_NAMES.resolveOrFail(REF_invokeVirtual, linker, null, NoSuchMethodException.class);
777 } catch (ReflectiveOperationException ex) {
778 throw newInternalError(ex);
779 }
780
781 // What is the external type of the lambda form?
782 MethodType mtype;
783 if (isGetter)
784 mtype = MethodType.methodType(ft);
785 else
786 mtype = MethodType.methodType(void.class, ft);
787 mtype = mtype.basicType(); // erase short to int, etc.
788 if (!isStatic)
789 mtype = mtype.insertParameterTypes(0, Object.class);
790 final int DMH_THIS = 0;
791 final int ARG_BASE = 1;
792 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
793 // if this is for non-static access, the base pointer is stored at this index:
794 final int OBJ_BASE = isStatic ? -1 : ARG_BASE;
795 // if this is for write access, the value to be written is stored at this index:
796 final int SET_VALUE = isGetter ? -1 : ARG_LIMIT - 1;
797 int nameCursor = ARG_LIMIT;
798 final int F_HOLDER = (isStatic ? nameCursor++ : -1); // static base if any
799 final int F_OFFSET = nameCursor++; // Either static offset or field offset.
800 final int OBJ_CHECK = (OBJ_BASE >= 0 ? nameCursor++ : -1);
801 final int U_HOLDER = nameCursor++; // UNSAFE holder
802 final int INIT_BAR = (needsInit ? nameCursor++ : -1);
803 final int PRE_CAST = (needsCast && !isGetter ? nameCursor++ : -1);
804 final int LINKER_CALL = nameCursor++;
805 final int POST_CAST = (needsCast && isGetter ? nameCursor++ : -1);
806 final int RESULT = nameCursor-1; // either the call or the cast
807 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
808 if (needsInit)
809 names[INIT_BAR] = new Name(getFunction(NF_ensureInitialized), names[DMH_THIS]);
810 if (needsCast && !isGetter)
811 names[PRE_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[SET_VALUE]);
812 Object[] outArgs = new Object[1 + linkerType.parameterCount()];
813 assert(outArgs.length == (isGetter ? 3 : 4));
814 outArgs[0] = names[U_HOLDER] = new Name(getFunction(NF_UNSAFE));
815 if (isStatic) {
816 outArgs[1] = names[F_HOLDER] = new Name(getFunction(NF_staticBase), names[DMH_THIS]);
817 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_staticOffset), names[DMH_THIS]);
818 } else {
819 outArgs[1] = names[OBJ_CHECK] = new Name(getFunction(NF_checkBase), names[OBJ_BASE]);
820 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_fieldOffset), names[DMH_THIS]);
821 }
822 if (!isGetter) {
823 outArgs[3] = (needsCast ? names[PRE_CAST] : names[SET_VALUE]);
824 }
825 for (Object a : outArgs) assert(a != null);
826 names[LINKER_CALL] = new Name(linker, outArgs);
827 if (needsCast && isGetter)
828 names[POST_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[LINKER_CALL]);
829 for (Name n : names) assert(n != null);
830
831 LambdaForm form;
832 if (needsCast || needsInit) {
833 // can't use the pre-generated form when casting and/or initializing
834 form = new LambdaForm(ARG_LIMIT, names, RESULT);
835 } else {
836 form = new LambdaForm(ARG_LIMIT, names, RESULT, kind);
837 }
838
839 if (LambdaForm.debugNames()) {
840 // add some detail to the lambdaForm debugname,
841 // significant only for debugging
842 StringBuilder nameBuilder = new StringBuilder(kind.methodName);
843 if (isStatic) {
844 nameBuilder.append("Static");
845 } else {
846 nameBuilder.append("Field");
847 }
848 if (needsCast) {
849 nameBuilder.append("Cast");
850 }
851 if (needsInit) {
852 nameBuilder.append("Init");
853 }
854 LambdaForm.associateWithDebugName(form, nameBuilder.toString());
855 }
856 return form;
857 }
858
859 /**
860 * Pre-initialized NamedFunctions for bootstrapping purposes.
861 */
862 static final byte NF_internalMemberName = 0,
863 NF_internalMemberNameEnsureInit = 1,
864 NF_ensureInitialized = 2,
865 NF_fieldOffset = 3,
866 NF_checkBase = 4,
867 NF_staticBase = 5,
868 NF_staticOffset = 6,
869 NF_checkCast = 7,
870 NF_allocateInstance = 8,
871 NF_constructorMethod = 9,
872 NF_UNSAFE = 10,
873 NF_checkReceiver = 11,
874 NF_LIMIT = 12;
875
876 private static final @Stable NamedFunction[] NFS = new NamedFunction[NF_LIMIT];
877
878 private static NamedFunction getFunction(byte func) {
879 NamedFunction nf = NFS[func];
880 if (nf != null) {
881 return nf;
882 }
883 // Each nf must be statically invocable or we get tied up in our bootstraps.
884 nf = NFS[func] = createFunction(func);
885 assert(InvokerBytecodeGenerator.isStaticallyInvocable(nf));
886 return nf;
887 }
888
889 private static final MethodType OBJ_OBJ_TYPE = MethodType.methodType(Object.class, Object.class);
890
891 private static final MethodType LONG_OBJ_TYPE = MethodType.methodType(long.class, Object.class);
892
893 private static NamedFunction createFunction(byte func) {
894 try {
895 switch (func) {
896 case NF_internalMemberName:
897 return getNamedFunction("internalMemberName", OBJ_OBJ_TYPE);
898 case NF_internalMemberNameEnsureInit:
899 return getNamedFunction("internalMemberNameEnsureInit", OBJ_OBJ_TYPE);
900 case NF_ensureInitialized:
901 return getNamedFunction("ensureInitialized", MethodType.methodType(void.class, Object.class));
902 case NF_fieldOffset:
903 return getNamedFunction("fieldOffset", LONG_OBJ_TYPE);
904 case NF_checkBase:
905 return getNamedFunction("checkBase", OBJ_OBJ_TYPE);
906 case NF_staticBase:
907 return getNamedFunction("staticBase", OBJ_OBJ_TYPE);
908 case NF_staticOffset:
909 return getNamedFunction("staticOffset", LONG_OBJ_TYPE);
910 case NF_checkCast:
911 return getNamedFunction("checkCast", MethodType.methodType(Object.class, Object.class, Object.class));
912 case NF_allocateInstance:
913 return getNamedFunction("allocateInstance", OBJ_OBJ_TYPE);
914 case NF_constructorMethod:
915 return getNamedFunction("constructorMethod", OBJ_OBJ_TYPE);
916 case NF_UNSAFE:
917 MemberName member = new MemberName(MethodHandleStatics.class, "UNSAFE", Unsafe.class, REF_getField);
918 return new NamedFunction(
919 MemberName.getFactory()
920 .resolveOrFail(REF_getField, member, DirectMethodHandle.class, NoSuchMethodException.class));
921 case NF_checkReceiver:
922 member = new MemberName(DirectMethodHandle.class, "checkReceiver", OBJ_OBJ_TYPE, REF_invokeVirtual);
923 return new NamedFunction(
924 MemberName.getFactory()
925 .resolveOrFail(REF_invokeVirtual, member, DirectMethodHandle.class, NoSuchMethodException.class));
926 default:
927 throw newInternalError("Unknown function: " + func);
928 }
929 } catch (ReflectiveOperationException ex) {
930 throw newInternalError(ex);
931 }
932 }
933
934 private static NamedFunction getNamedFunction(String name, MethodType type)
935 throws ReflectiveOperationException
936 {
937 MemberName member = new MemberName(DirectMethodHandle.class, name, type, REF_invokeStatic);
938 return new NamedFunction(
939 MemberName.getFactory()
940 .resolveOrFail(REF_invokeStatic, member, DirectMethodHandle.class, NoSuchMethodException.class));
941 }
942
943 static {
944 // The Holder class will contain pre-generated DirectMethodHandles resolved
945 // speculatively using MemberName.getFactory().resolveOrNull. However, that
946 // doesn't initialize the class, which subtly breaks inlining etc. By forcing
947 // initialization of the Holder class we avoid these issues.
948 UNSAFE.ensureClassInitialized(Holder.class);
949 }
950
951 /* Placeholder class for DirectMethodHandles generated ahead of time */
952 final class Holder {}
953 }