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
55 // Constructors and factory methods in this class *must* be package scoped or private.
56 private DirectMethodHandle(MethodType mtype, LambdaForm form, MemberName member) {
57 super(mtype, form);
58 if (!member.isResolved()) throw new InternalError();
59
60 if (member.getDeclaringClass().isInterface() &&
61 member.getReferenceKind() == REF_invokeInterface &&
62 member.isMethod() && !member.isAbstract()) {
63 // Check for corner case: invokeinterface of Object method
64 MemberName m = new MemberName(Object.class, member.getName(), member.getMethodType(), member.getReferenceKind());
65 m = MemberName.getFactory().resolveOrNull(m.getReferenceKind(), m, null);
66 if (m != null && m.isPublic()) {
67 assert(member.getReferenceKind() == m.getReferenceKind()); // else this.form is wrong
68 member = m;
69 }
70 }
71
72 this.member = member;
73 }
74
75 // Factory methods:
76 static DirectMethodHandle make(byte refKind, Class<?> refc, MemberName member, Class<?> callerClass) {
77 MethodType mtype = member.getMethodOrFieldType();
78 if (!member.isStatic()) {
79 if (!member.getDeclaringClass().isAssignableFrom(refc) || member.isConstructor())
80 throw new InternalError(member.toString());
81 mtype = mtype.insertParameterTypes(0, refc.isValue() ? refc.asValueType() : refc);
82 }
83 if (!member.isField()) {
84 // refKind reflects the original type of lookup via findSpecial or
85 // findVirtual etc.
86 switch (refKind) {
87 case REF_invokeSpecial: {
88 member = member.asSpecial();
89 // if caller is an interface we need to adapt to get the
90 // receiver check inserted
91 if (callerClass == null) {
92 throw new InternalError("callerClass must not be null for REF_invokeSpecial");
93 }
94 LambdaForm lform = preparedLambdaForm(member, callerClass.isInterface());
95 return new Special(mtype, lform, member, callerClass);
96 }
97 case REF_invokeInterface: {
98 // for interfaces we always need the receiver typecheck,
99 // so we always pass 'true' to ensure we adapt if needed
100 // to include the REF_invokeSpecial case
101 LambdaForm lform = preparedLambdaForm(member, true);
102 return new Interface(mtype, lform, member, refc);
103 }
104 default: {
105 LambdaForm lform = preparedLambdaForm(member);
106 return new DirectMethodHandle(mtype, lform, member);
107 }
108 }
109 } else {
110 LambdaForm lform = preparedFieldLambdaForm(member);
111 if (member.isStatic()) {
112 long offset = MethodHandleNatives.staticFieldOffset(member);
113 Object base = MethodHandleNatives.staticFieldBase(member);
114 return member.canBeNull() ? new StaticAccessor(mtype, lform, member, base, offset)
115 : new StaticValueAccessor(mtype, lform, member, base, offset);
116 } else {
117 long offset = MethodHandleNatives.objectFieldOffset(member);
118 assert(offset == (int)offset);
119 return member.canBeNull() ? new Accessor(mtype, lform, member, (int)offset)
120 : new ValueAccessor(mtype, lform, member, (int)offset);
121
122 }
123 }
124 }
125 static DirectMethodHandle make(Class<?> refc, MemberName member) {
126 byte refKind = member.getReferenceKind();
127 if (refKind == REF_invokeSpecial)
128 refKind = REF_invokeVirtual;
129 return make(refKind, refc, member, null /* no callerClass context */);
130 }
131 static DirectMethodHandle make(MemberName member) {
132 if (member.isConstructor())
133 return makeAllocator(member);
134 return make(member.getDeclaringClass(), member);
135 }
136 private static DirectMethodHandle makeAllocator(MemberName ctor) {
137 assert(ctor.isConstructor() && ctor.getName().equals("<init>"));
138 Class<?> instanceClass = ctor.getDeclaringClass();
139 if (instanceClass.isValue())
140 instanceClass = instanceClass.asValueType(); // convert to Q-Type
141 ctor = ctor.asConstructor();
142 assert(ctor.isConstructor() && ctor.getReferenceKind() == REF_newInvokeSpecial) : ctor;
143 MethodType mtype = ctor.getMethodType().changeReturnType(instanceClass);
144 LambdaForm lform = preparedLambdaForm(ctor);
145 MemberName init = ctor.asSpecial();
146 assert(init.getMethodType().returnType() == void.class);
147 return new Constructor(mtype, lform, ctor, init, instanceClass);
148 }
149
150 @Override
151 BoundMethodHandle rebind() {
152 return BoundMethodHandle.makeReinvoker(this);
153 }
154
155 @Override
156 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
157 assert(this.getClass() == DirectMethodHandle.class); // must override in subclasses
158 return new DirectMethodHandle(mt, lf, member);
159 }
160
161 @Override
162 String internalProperties() {
163 return "\n& DMH.MN="+internalMemberName();
164 }
165
166 //// Implementation methods.
167 @Override
168 @ForceInline
169 MemberName internalMemberName() {
170 return member;
171 }
172
173 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
174
175 /**
176 * Create a LF which can invoke the given method.
177 * Cache and share this structure among all methods with
178 * the same basicType and refKind.
179 */
180 private static LambdaForm preparedLambdaForm(MemberName m, boolean adaptToSpecialIfc) {
181 assert(m.isInvocable()) : m; // call preparedFieldLambdaForm instead
182 MethodType mtype = m.getInvocationType().basicType();
183 assert(!m.isMethodHandleInvoke()) : m;
184 int which;
185 // MemberName.getReferenceKind represents the JVM optimized form of the call
186 // as distinct from the "kind" passed to DMH.make which represents the original
187 // bytecode-equivalent request. Specifically private/final methods that use a direct
188 // call have getReferenceKind adapted to REF_invokeSpecial, even though the actual
189 // invocation mode may be invokevirtual or invokeinterface.
190 switch (m.getReferenceKind()) {
191 case REF_invokeVirtual: which = LF_INVVIRTUAL; break;
192 case REF_invokeStatic: which = LF_INVSTATIC; break;
193 case REF_invokeSpecial: which = LF_INVSPECIAL; break;
194 case REF_invokeInterface: which = LF_INVINTERFACE; break;
195 case REF_newInvokeSpecial: which = LF_NEWINVSPECIAL; break;
196 default: throw new InternalError(m.toString());
197 }
198 if (which == LF_INVSTATIC && shouldBeInitialized(m)) {
199 // precompute the barrier-free version:
200 preparedLambdaForm(mtype, which);
201 which = LF_INVSTATIC_INIT;
202 }
203 if (which == LF_INVSPECIAL && adaptToSpecialIfc) {
204 which = LF_INVSPECIAL_IFC;
205 }
206 LambdaForm lform = preparedLambdaForm(mtype, which);
207 maybeCompile(lform, m);
208 assert(lform.methodType().dropParameterTypes(0, 1)
209 .equals(m.getInvocationType().basicType()))
210 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
211 return lform;
212 }
213
214 private static LambdaForm preparedLambdaForm(MemberName m) {
215 return preparedLambdaForm(m, false);
216 }
217
218 private static LambdaForm preparedLambdaForm(MethodType mtype, int which) {
219 LambdaForm lform = mtype.form().cachedLambdaForm(which);
220 if (lform != null) return lform;
221 lform = makePreparedLambdaForm(mtype, which);
222 return mtype.form().setCachedLambdaForm(which, lform);
223 }
224
225 static LambdaForm makePreparedLambdaForm(MethodType mtype, int which) {
226 boolean needsInit = (which == LF_INVSTATIC_INIT);
227 boolean doesAlloc = (which == LF_NEWINVSPECIAL);
228 boolean needsReceiverCheck = (which == LF_INVINTERFACE ||
229 which == LF_INVSPECIAL_IFC);
230
231 String linkerName;
232 LambdaForm.Kind kind;
233 switch (which) {
234 case LF_INVVIRTUAL: linkerName = "linkToVirtual"; kind = DIRECT_INVOKE_VIRTUAL; break;
235 case LF_INVSTATIC: linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC; break;
236 case LF_INVSTATIC_INIT:linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC_INIT; break;
237 case LF_INVSPECIAL_IFC:linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL_IFC; break;
238 case LF_INVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL; break;
239 case LF_INVINTERFACE: linkerName = "linkToInterface"; kind = DIRECT_INVOKE_INTERFACE; break;
240 case LF_NEWINVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_NEW_INVOKE_SPECIAL; break;
241 default: throw new InternalError("which="+which);
242 }
243
244 MethodType mtypeWithArg = mtype.appendParameterTypes(MemberName.class);
245 if (doesAlloc)
246 mtypeWithArg = mtypeWithArg
247 .insertParameterTypes(0, Object.class) // insert newly allocated obj
248 .changeReturnType(void.class); // <init> returns void
249 MemberName linker = new MemberName(MethodHandle.class, linkerName, mtypeWithArg, REF_invokeStatic);
250 try {
251 linker = IMPL_NAMES.resolveOrFail(REF_invokeStatic, linker, null, NoSuchMethodException.class);
252 } catch (ReflectiveOperationException ex) {
253 throw newInternalError(ex);
254 }
255 final int DMH_THIS = 0;
256 final int ARG_BASE = 1;
257 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
258 int nameCursor = ARG_LIMIT;
259 final int NEW_OBJ = (doesAlloc ? nameCursor++ : -1);
260 final int GET_MEMBER = nameCursor++;
261 final int CHECK_RECEIVER = (needsReceiverCheck ? nameCursor++ : -1);
262 final int LINKER_CALL = nameCursor++;
263 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
264 assert(names.length == nameCursor);
265 if (doesAlloc) {
266 // names = { argx,y,z,... new C, init method }
267 names[NEW_OBJ] = new Name(getFunction(NF_allocateInstance), names[DMH_THIS]);
268 names[GET_MEMBER] = new Name(getFunction(NF_constructorMethod), names[DMH_THIS]);
269 } else if (needsInit) {
270 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberNameEnsureInit), names[DMH_THIS]);
271 } else {
272 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberName), names[DMH_THIS]);
273 }
274 assert(findDirectMethodHandle(names[GET_MEMBER]) == names[DMH_THIS]);
275 Object[] outArgs = Arrays.copyOfRange(names, ARG_BASE, GET_MEMBER+1, Object[].class);
276 if (needsReceiverCheck) {
277 names[CHECK_RECEIVER] = new Name(getFunction(NF_checkReceiver), names[DMH_THIS], names[ARG_BASE]);
278 outArgs[0] = names[CHECK_RECEIVER];
279 }
280 assert(outArgs[outArgs.length-1] == names[GET_MEMBER]); // look, shifted args!
281 int result = LAST_RESULT;
282 if (doesAlloc) {
283 assert(outArgs[outArgs.length-2] == names[NEW_OBJ]); // got to move this one
284 System.arraycopy(outArgs, 0, outArgs, 1, outArgs.length-2);
285 outArgs[0] = names[NEW_OBJ];
286 result = NEW_OBJ;
287 }
288 names[LINKER_CALL] = new Name(linker, outArgs);
289 LambdaForm lform = new LambdaForm(ARG_LIMIT, names, result, kind);
290
291 // This is a tricky bit of code. Don't send it through the LF interpreter.
292 lform.compileToBytecode();
293 return lform;
294 }
295
296 /* assert */ static Object findDirectMethodHandle(Name name) {
297 if (name.function.equals(getFunction(NF_internalMemberName)) ||
298 name.function.equals(getFunction(NF_internalMemberNameEnsureInit)) ||
299 name.function.equals(getFunction(NF_constructorMethod))) {
300 assert(name.arguments.length == 1);
301 return name.arguments[0];
302 }
303 return null;
304 }
305
306 private static void maybeCompile(LambdaForm lform, MemberName m) {
307 if (lform.vmentry == null && VerifyAccess.isSamePackage(m.getDeclaringClass(), MethodHandle.class))
308 // Help along bootstrapping...
309 lform.compileToBytecode();
310 }
311
312 /** Static wrapper for DirectMethodHandle.internalMemberName. */
313 @ForceInline
314 /*non-public*/ static Object internalMemberName(Object mh) {
315 return ((DirectMethodHandle)mh).member;
316 }
317
318 /** Static wrapper for DirectMethodHandle.internalMemberName.
319 * This one also forces initialization.
320 */
321 /*non-public*/ static Object internalMemberNameEnsureInit(Object mh) {
322 DirectMethodHandle dmh = (DirectMethodHandle)mh;
323 dmh.ensureInitialized();
324 return dmh.member;
325 }
326
327 /*non-public*/ static
328 boolean shouldBeInitialized(MemberName member) {
329 switch (member.getReferenceKind()) {
330 case REF_invokeStatic:
331 case REF_getStatic:
332 case REF_putStatic:
333 case REF_newInvokeSpecial:
334 break;
335 default:
336 // No need to initialize the class on this kind of member.
337 return false;
338 }
339 Class<?> cls = member.getDeclaringClass();
340 if (cls == ValueConversions.class ||
341 cls == MethodHandleImpl.class ||
342 cls == Invokers.class) {
343 // These guys have lots of <clinit> DMH creation but we know
344 // the MHs will not be used until the system is booted.
345 return false;
346 }
347 if (VerifyAccess.isSamePackage(MethodHandle.class, cls) ||
348 VerifyAccess.isSamePackage(ValueConversions.class, cls)) {
349 // It is a system class. It is probably in the process of
350 // being initialized, but we will help it along just to be safe.
351 if (UNSAFE.shouldBeInitialized(cls)) {
352 UNSAFE.ensureClassInitialized(cls);
353 }
354 return false;
355 }
356 return UNSAFE.shouldBeInitialized(cls);
357 }
358
359 private static class EnsureInitialized extends ClassValue<WeakReference<Thread>> {
360 @Override
361 protected WeakReference<Thread> computeValue(Class<?> type) {
362 UNSAFE.ensureClassInitialized(type);
363 if (UNSAFE.shouldBeInitialized(type))
364 // If the previous call didn't block, this can happen.
365 // We are executing inside <clinit>.
366 return new WeakReference<>(Thread.currentThread());
367 return null;
368 }
369 static final EnsureInitialized INSTANCE = new EnsureInitialized();
370 }
371
372 private void ensureInitialized() {
373 if (checkInitialized(member)) {
374 // The coast is clear. Delete the <clinit> barrier.
375 if (member.isField())
376 updateForm(preparedFieldLambdaForm(member));
377 else
378 updateForm(preparedLambdaForm(member));
379 }
380 }
381 private static boolean checkInitialized(MemberName member) {
382 Class<?> defc = member.getDeclaringClass();
383 WeakReference<Thread> ref = EnsureInitialized.INSTANCE.get(defc);
384 if (ref == null) {
385 return true; // the final state
386 }
387 Thread clinitThread = ref.get();
388 // Somebody may still be running defc.<clinit>.
389 if (clinitThread == Thread.currentThread()) {
390 // If anybody is running defc.<clinit>, it is this thread.
391 if (UNSAFE.shouldBeInitialized(defc))
392 // Yes, we are running it; keep the barrier for now.
393 return false;
394 } else {
395 // We are in a random thread. Block.
396 UNSAFE.ensureClassInitialized(defc);
397 }
398 assert(!UNSAFE.shouldBeInitialized(defc));
399 // put it into the final state
400 EnsureInitialized.INSTANCE.remove(defc);
401 return true;
402 }
403
404 /*non-public*/ static void ensureInitialized(Object mh) {
405 ((DirectMethodHandle)mh).ensureInitialized();
406 }
407
408 /** This subclass represents invokespecial instructions. */
409 static class Special extends DirectMethodHandle {
410 private final Class<?> caller;
411 private Special(MethodType mtype, LambdaForm form, MemberName member, Class<?> caller) {
412 super(mtype, form, member);
413 this.caller = caller;
414 }
415 @Override
416 boolean isInvokeSpecial() {
417 return true;
418 }
419 @Override
420 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
421 return new Special(mt, lf, member, caller);
422 }
423 Object checkReceiver(Object recv) {
424 if (!caller.isInstance(recv)) {
425 String msg = String.format("Receiver class %s is not a subclass of caller class %s",
426 recv.getClass().getName(), caller.getName());
427 throw new IncompatibleClassChangeError(msg);
428 }
429 return recv;
430 }
431 }
432
433 /** This subclass represents invokeinterface instructions. */
434 static class Interface extends DirectMethodHandle {
435 private final Class<?> refc;
436 private Interface(MethodType mtype, LambdaForm form, MemberName member, Class<?> refc) {
437 super(mtype, form, member);
438 assert refc.isInterface() : refc;
439 this.refc = refc;
440 }
441 @Override
442 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
443 return new Interface(mt, lf, member, refc);
444 }
445 @Override
446 Object checkReceiver(Object recv) {
447 if (!refc.isInstance(recv)) {
448 String msg = String.format("Receiver class %s does not implement the requested interface %s",
449 recv.getClass().getName(), refc.getName());
450 throw new IncompatibleClassChangeError(msg);
451 }
452 return recv;
453 }
454 }
455
456 /** Used for interface receiver type checks, by Interface and Special modes. */
457 Object checkReceiver(Object recv) {
458 throw new InternalError("Should only be invoked on a subclass");
459 }
460
461
462 /** This subclass handles constructor references. */
463 static class Constructor extends DirectMethodHandle {
464 final MemberName initMethod;
465 final Class<?> instanceClass;
466
467 private Constructor(MethodType mtype, LambdaForm form, MemberName constructor,
468 MemberName initMethod, Class<?> instanceClass) {
469 super(mtype, form, constructor);
470 this.initMethod = initMethod;
471 this.instanceClass = instanceClass;
472 assert(initMethod.isResolved());
473 }
474 @Override
475 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
476 return new Constructor(mt, lf, member, initMethod, instanceClass);
477 }
478 }
479
480 /*non-public*/ static Object constructorMethod(Object mh) {
481 Constructor dmh = (Constructor)mh;
482 return dmh.initMethod;
483 }
484
485 /*non-public*/ static Object allocateInstance(Object mh) throws InstantiationException {
486 Constructor dmh = (Constructor)mh;
487 return UNSAFE.allocateInstance(dmh.instanceClass);
488 }
489
490 /** This subclass handles non-static field references. */
491 static class Accessor extends DirectMethodHandle {
492 final Class<?> fieldType;
493 final int fieldOffset;
494 private Accessor(MethodType mtype, LambdaForm form, MemberName member,
495 int fieldOffset) {
496 super(mtype, form, member);
497 this.fieldType = member.getFieldType();
498 this.fieldOffset = fieldOffset;
499 }
500
501 @Override Object checkCast(Object obj) {
502 return fieldType.cast(obj);
503 }
504 @Override
505 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
506 return new Accessor(mt, lf, member, fieldOffset);
507 }
508 }
509
510 static class ValueAccessor extends Accessor {
511 private ValueAccessor(MethodType mtype, LambdaForm form, MemberName member,
512 int fieldOffset) {
513 super(mtype, form, member, fieldOffset);
514 }
515
516 @Override Object checkCast(Object obj) {
517 return fieldType.cast(Objects.requireNonNull(obj));
518 }
519 @Override
520 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
521 return new ValueAccessor(mt, lf, member, fieldOffset);
522 }
523 }
524
525 @ForceInline
526 /*non-public*/ static long fieldOffset(Object accessorObj) {
527 // Note: We return a long because that is what Unsafe.getObject likes.
528 // We store a plain int because it is more compact.
529 return ((Accessor)accessorObj).fieldOffset;
530 }
531
532 @ForceInline
533 /*non-public*/ static Object checkBase(Object obj) {
534 // Note that the object's class has already been verified,
535 // since the parameter type of the Accessor method handle
536 // is either member.getDeclaringClass or a subclass.
537 // This was verified in DirectMethodHandle.make.
538 // Therefore, the only remaining check is for null.
539 // Since this check is *not* guaranteed by Unsafe.getInt
540 // and its siblings, we need to make an explicit one here.
541 return Objects.requireNonNull(obj);
542 }
543
544 /** This subclass handles static field references. */
545 static class StaticAccessor extends DirectMethodHandle {
546 final Class<?> fieldType;
547 final Object staticBase;
548 final long staticOffset;
549
550 private StaticAccessor(MethodType mtype, LambdaForm form, MemberName member,
551 Object staticBase, long staticOffset) {
552 super(mtype, form, member);
553 this.fieldType = member.getFieldType();
554 this.staticBase = staticBase;
555 this.staticOffset = staticOffset;
556 }
557
558 @Override Object checkCast(Object obj) {
559 return fieldType.cast(obj);
560 }
561 @Override
562 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
563 return new StaticAccessor(mt, lf, member, staticBase, staticOffset);
564 }
565 }
566
567 static class StaticValueAccessor extends StaticAccessor {
568 private StaticValueAccessor(MethodType mtype, LambdaForm form, MemberName member,
569 Object staticBase, long staticOffset) {
570 super(mtype, form, member, staticBase, staticOffset);
571 }
572
573 @Override Object checkCast(Object obj) {
574 return fieldType.cast(Objects.requireNonNull(obj));
575 }
576 @Override
577 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
578 return new StaticValueAccessor(mt, lf, member, staticBase, staticOffset);
579 }
580 }
581
582
583 @ForceInline
584 /*non-public*/ static Object nullCheck(Object obj) {
585 return Objects.requireNonNull(obj);
586 }
587
588 @ForceInline
589 /*non-public*/ static Object staticBase(Object accessorObj) {
590 return ((StaticAccessor)accessorObj).staticBase;
591 }
592
593 @ForceInline
594 /*non-public*/ static long staticOffset(Object accessorObj) {
595 return ((StaticAccessor)accessorObj).staticOffset;
596 }
597
598 @ForceInline
599 /*non-public*/ static Object checkCast(Object mh, Object obj) {
600 return ((DirectMethodHandle) mh).checkCast(obj);
601 }
602
603 @ForceInline
604 /*non-public*/ static Class<?> fieldValueType(Object accessorObj) {
605 return ((Accessor) accessorObj).fieldType;
606 }
607
608 @ForceInline
609 /*non-public*/ static Class<?> staticFieldValueType(Object accessorObj) {
610 return ((StaticAccessor) accessorObj).fieldType;
611 }
612
613 Object checkCast(Object obj) {
614 return member.getReturnType().cast(obj);
615 }
616
617 // Caching machinery for field accessors:
618 static final byte
619 AF_GETFIELD = 0,
620 AF_PUTFIELD = 1,
621 AF_GETSTATIC = 2,
622 AF_PUTSTATIC = 3,
623 AF_GETSTATIC_INIT = 4,
624 AF_PUTSTATIC_INIT = 5,
625 AF_LIMIT = 6;
626 // Enumerate the different field kinds using Wrapper,
627 // with an extra case added for checked references and value field access
628 static final int
629 FT_LAST_WRAPPER = Wrapper.COUNT-1,
630 FT_UNCHECKED_REF = Wrapper.OBJECT.ordinal(),
631 FT_CHECKED_REF = FT_LAST_WRAPPER+1,
632 FT_CHECKED_VALUE = FT_LAST_WRAPPER+2, // flattened and non-flattened
633 FT_LIMIT = FT_LAST_WRAPPER+4;
634 private static int afIndex(byte formOp, boolean isVolatile, boolean isFlatValue, int ftypeKind) {
635 return ((formOp * FT_LIMIT * 2)
636 + (isVolatile ? FT_LIMIT : 0)
637 + (isFlatValue ? 1 : 0)
638 + ftypeKind);
639 }
640 @Stable
641 private static final LambdaForm[] ACCESSOR_FORMS
642 = new LambdaForm[afIndex(AF_LIMIT, false, false, 0)];
643 static int ftypeKind(Class<?> ftype, boolean canBeNull) {
644 if (ftype.isPrimitive())
645 return Wrapper.forPrimitiveType(ftype).ordinal();
646 else if (VerifyType.isNullReferenceConversion(Object.class, ftype)) {
647 return FT_UNCHECKED_REF;
648 } else
649 // null check for value type in addition to check cast
650 return canBeNull ? FT_CHECKED_REF : FT_CHECKED_VALUE;
651 }
652
653 /**
654 * Create a LF which can access the given field.
655 * Cache and share this structure among all fields with
656 * the same basicType and refKind.
657 */
658 private static LambdaForm preparedFieldLambdaForm(MemberName m) {
659 Class<?> ftype = m.getFieldType();
660 boolean isVolatile = m.isVolatile();
661 boolean isFlatValue = m.isFlatValue();
662 boolean canBeNull = m.canBeNull();
663 byte formOp;
664 switch (m.getReferenceKind()) {
665 case REF_getField: formOp = AF_GETFIELD; break;
666 case REF_putField: formOp = AF_PUTFIELD; break;
667 case REF_getStatic: formOp = AF_GETSTATIC; break;
668 case REF_putStatic: formOp = AF_PUTSTATIC; break;
669 default: throw new InternalError(m.toString());
670 }
671 if (shouldBeInitialized(m)) {
672 // precompute the barrier-free version:
673 preparedFieldLambdaForm(formOp, isVolatile, isFlatValue , canBeNull, ftype);
674 assert((AF_GETSTATIC_INIT - AF_GETSTATIC) ==
675 (AF_PUTSTATIC_INIT - AF_PUTSTATIC));
676 formOp += (AF_GETSTATIC_INIT - AF_GETSTATIC);
677 }
678 LambdaForm lform = preparedFieldLambdaForm(formOp, isVolatile, isFlatValue , canBeNull, ftype);
679 maybeCompile(lform, m);
680 assert(lform.methodType().dropParameterTypes(0, 1)
681 .equals(m.getInvocationType().basicType()))
682 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
683 return lform;
684 }
685
686 private static LambdaForm preparedFieldLambdaForm(byte formOp, boolean isVolatile, boolean isFlatValue, boolean canBeNull, Class<?> ftype) {
687 int ftypeKind = ftypeKind(ftype, canBeNull);
688 int afIndex = afIndex(formOp, isVolatile, isFlatValue, ftypeKind);
689 LambdaForm lform = ACCESSOR_FORMS[afIndex];
690 if (lform != null) return lform;
691 lform = makePreparedFieldLambdaForm(formOp, isVolatile, isFlatValue, ftypeKind);
692 ACCESSOR_FORMS[afIndex] = lform; // don't bother with a CAS
693 return lform;
694 }
695
696 private static final Wrapper[] ALL_WRAPPERS = Wrapper.values();
697
698 private static Kind getFieldKind(boolean isGetter, boolean isVolatile, boolean isFlatValue, Wrapper wrapper) {
699 if (isGetter) {
700 if (isVolatile) {
701 switch (wrapper) {
702 case BOOLEAN: return GET_BOOLEAN_VOLATILE;
703 case BYTE: return GET_BYTE_VOLATILE;
704 case SHORT: return GET_SHORT_VOLATILE;
705 case CHAR: return GET_CHAR_VOLATILE;
706 case INT: return GET_INT_VOLATILE;
707 case LONG: return GET_LONG_VOLATILE;
708 case FLOAT: return GET_FLOAT_VOLATILE;
709 case DOUBLE: return GET_DOUBLE_VOLATILE;
710 case OBJECT: return isFlatValue ? GET_VALUE_VOLATILE : GET_REFERENCE_VOLATILE;
711 }
712 } else {
713 switch (wrapper) {
714 case BOOLEAN: return GET_BOOLEAN;
715 case BYTE: return GET_BYTE;
716 case SHORT: return GET_SHORT;
717 case CHAR: return GET_CHAR;
718 case INT: return GET_INT;
719 case LONG: return GET_LONG;
720 case FLOAT: return GET_FLOAT;
721 case DOUBLE: return GET_DOUBLE;
722 case OBJECT: return isFlatValue ? GET_VALUE : GET_REFERENCE;
723 }
724 }
725 } else {
726 if (isVolatile) {
727 switch (wrapper) {
728 case BOOLEAN: return PUT_BOOLEAN_VOLATILE;
729 case BYTE: return PUT_BYTE_VOLATILE;
730 case SHORT: return PUT_SHORT_VOLATILE;
731 case CHAR: return PUT_CHAR_VOLATILE;
732 case INT: return PUT_INT_VOLATILE;
733 case LONG: return PUT_LONG_VOLATILE;
734 case FLOAT: return PUT_FLOAT_VOLATILE;
735 case DOUBLE: return PUT_DOUBLE_VOLATILE;
736 case OBJECT: return isFlatValue ? PUT_VALUE_VOLATILE : PUT_REFERENCE_VOLATILE;
737 }
738 } else {
739 switch (wrapper) {
740 case BOOLEAN: return PUT_BOOLEAN;
741 case BYTE: return PUT_BYTE;
742 case SHORT: return PUT_SHORT;
743 case CHAR: return PUT_CHAR;
744 case INT: return PUT_INT;
745 case LONG: return PUT_LONG;
746 case FLOAT: return PUT_FLOAT;
747 case DOUBLE: return PUT_DOUBLE;
748 case OBJECT: return isFlatValue ? PUT_VALUE : PUT_REFERENCE;
749 }
750 }
751 }
752 throw new AssertionError("Invalid arguments");
753 }
754
755 static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, boolean isFlatValue, int ftypeKind) {
756 boolean isGetter = (formOp & 1) == (AF_GETFIELD & 1);
757 boolean isStatic = (formOp >= AF_GETSTATIC);
758 boolean needsInit = (formOp >= AF_GETSTATIC_INIT);
759 boolean needsCast = (ftypeKind == FT_CHECKED_REF || ftypeKind == FT_CHECKED_VALUE);
760 Wrapper fw = (needsCast ? Wrapper.OBJECT : ALL_WRAPPERS[ftypeKind]);
761 Class<?> ft = fw.primitiveType();
762 assert(needsCast ? true : ftypeKind(ft, ftypeKind != FT_CHECKED_VALUE) == ftypeKind);
763
764 // getObject, putIntVolatile, etc.
765 Kind kind = getFieldKind(isGetter, isVolatile, isFlatValue, fw);
766
767 MethodType linkerType;
768 if (isFlatValue) {
769 linkerType = isGetter ? MethodType.methodType(ft, Object.class, long.class, Class.class)
770 : MethodType.methodType(void.class, Object.class, long.class, Class.class, ft);
771 } else {
772 linkerType = isGetter ? MethodType.methodType(ft, Object.class, long.class)
773 : MethodType.methodType(void.class, Object.class, long.class, ft);
774 }
775 MemberName linker = new MemberName(Unsafe.class, kind.methodName, linkerType, REF_invokeVirtual);
776 try {
777 linker = IMPL_NAMES.resolveOrFail(REF_invokeVirtual, linker, null, NoSuchMethodException.class);
778 } catch (ReflectiveOperationException ex) {
779 throw newInternalError(ex);
780 }
781
782 // What is the external type of the lambda form?
783 MethodType mtype;
784 if (isGetter)
785 mtype = MethodType.methodType(ft);
786 else
787 mtype = MethodType.methodType(void.class, ft);
788 mtype = mtype.basicType(); // erase short to int, etc.
789 if (!isStatic)
790 mtype = mtype.insertParameterTypes(0, Object.class);
791 final int DMH_THIS = 0;
792 final int ARG_BASE = 1;
793 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
794 // if this is for non-static access, the base pointer is stored at this index:
795 final int OBJ_BASE = isStatic ? -1 : ARG_BASE;
796 // if this is for write access, the value to be written is stored at this index:
797 final int SET_VALUE = isGetter ? -1 : ARG_LIMIT - 1;
798 int nameCursor = ARG_LIMIT;
799 final int F_HOLDER = (isStatic ? nameCursor++ : -1); // static base if any
800 final int F_OFFSET = nameCursor++; // Either static offset or field offset.
801 final int OBJ_CHECK = (OBJ_BASE >= 0 ? nameCursor++ : -1);
802 final int U_HOLDER = nameCursor++; // UNSAFE holder
803 final int INIT_BAR = (needsInit ? nameCursor++ : -1);
804 final int VALUE_TYPE = (isFlatValue ? nameCursor++ : -1);
805 final int PRE_CAST = (needsCast && !isGetter ? nameCursor++ : -1);
806 final int LINKER_CALL = nameCursor++;
807 final int POST_CAST = (needsCast && isGetter ? nameCursor++ : -1);
808 final int RESULT = nameCursor-1; // either the call or the cast
809 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
810 if (needsInit)
811 names[INIT_BAR] = new Name(getFunction(NF_ensureInitialized), names[DMH_THIS]);
812 if (needsCast && !isGetter)
813 names[PRE_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[SET_VALUE]);
814 Object[] outArgs = new Object[1 + linkerType.parameterCount()];
815 assert (outArgs.length == (isFlatValue ? (isGetter ? 4 : 5) : (isGetter ? 3 : 4)));
816 outArgs[0] = names[U_HOLDER] = new Name(getFunction(NF_UNSAFE));
817 if (isStatic) {
818 outArgs[1] = names[F_HOLDER] = new Name(getFunction(NF_staticBase), names[DMH_THIS]);
819 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_staticOffset), names[DMH_THIS]);
820 } else {
821 outArgs[1] = names[OBJ_CHECK] = new Name(getFunction(NF_checkBase), names[OBJ_BASE]);
822 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_fieldOffset), names[DMH_THIS]);
823 }
824 int x = 3;
825 if (isFlatValue) {
826 outArgs[x++] = names[VALUE_TYPE] = isStatic ? new Name(getFunction(NF_staticFieldValueType), names[DMH_THIS])
827 : new Name(getFunction(NF_fieldValueType), names[DMH_THIS]);
828 }
829 if (!isGetter) {
830 outArgs[x] = (needsCast ? names[PRE_CAST] : names[SET_VALUE]);
831 }
832 for (Object a : outArgs) assert(a != null);
833 names[LINKER_CALL] = new Name(linker, outArgs);
834 if (needsCast && isGetter)
835 names[POST_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[LINKER_CALL]);
836 for (Name n : names) assert(n != null);
837
838 LambdaForm form;
839 if (needsCast || needsInit) {
840 // can't use the pre-generated form when casting and/or initializing
841 form = new LambdaForm(ARG_LIMIT, names, RESULT);
842 } else {
843 form = new LambdaForm(ARG_LIMIT, names, RESULT, kind);
844 }
845
846 if (LambdaForm.debugNames()) {
847 // add some detail to the lambdaForm debugname,
848 // significant only for debugging
849 StringBuilder nameBuilder = new StringBuilder(kind.methodName);
850 if (isStatic) {
851 nameBuilder.append("Static");
852 } else {
853 nameBuilder.append("Field");
854 }
855 if (needsCast) {
856 nameBuilder.append("Cast");
857 }
858 if (needsInit) {
859 nameBuilder.append("Init");
860 }
861 LambdaForm.associateWithDebugName(form, nameBuilder.toString());
862 }
863 return form;
864 }
865
866 /**
867 * Pre-initialized NamedFunctions for bootstrapping purposes.
868 */
869 static final byte NF_internalMemberName = 0,
870 NF_internalMemberNameEnsureInit = 1,
871 NF_ensureInitialized = 2,
872 NF_fieldOffset = 3,
873 NF_checkBase = 4,
874 NF_staticBase = 5,
875 NF_staticOffset = 6,
876 NF_checkCast = 7,
877 NF_allocateInstance = 8,
878 NF_constructorMethod = 9,
879 NF_UNSAFE = 10,
880 NF_checkReceiver = 11,
881 NF_fieldValueType = 12,
882 NF_staticFieldValueType = 13,
883 NF_LIMIT = 14;
884
885 private static final @Stable NamedFunction[] NFS = new NamedFunction[NF_LIMIT];
886
887 private static NamedFunction getFunction(byte func) {
888 NamedFunction nf = NFS[func];
889 if (nf != null) {
890 return nf;
891 }
892 // Each nf must be statically invocable or we get tied up in our bootstraps.
893 nf = NFS[func] = createFunction(func);
894 assert(InvokerBytecodeGenerator.isStaticallyInvocable(nf));
895 return nf;
896 }
897
898 private static final MethodType CLS_OBJ_TYPE = MethodType.methodType(Class.class, Object.class);
899
900 private static final MethodType OBJ_OBJ_TYPE = MethodType.methodType(Object.class, Object.class);
901
902 private static final MethodType LONG_OBJ_TYPE = MethodType.methodType(long.class, Object.class);
903
904 private static NamedFunction createFunction(byte func) {
905 try {
906 switch (func) {
907 case NF_internalMemberName:
908 return getNamedFunction("internalMemberName", OBJ_OBJ_TYPE);
909 case NF_internalMemberNameEnsureInit:
910 return getNamedFunction("internalMemberNameEnsureInit", OBJ_OBJ_TYPE);
911 case NF_ensureInitialized:
912 return getNamedFunction("ensureInitialized", MethodType.methodType(void.class, Object.class));
913 case NF_fieldOffset:
914 return getNamedFunction("fieldOffset", LONG_OBJ_TYPE);
915 case NF_checkBase:
916 return getNamedFunction("checkBase", OBJ_OBJ_TYPE);
917 case NF_staticBase:
918 return getNamedFunction("staticBase", OBJ_OBJ_TYPE);
919 case NF_staticOffset:
920 return getNamedFunction("staticOffset", LONG_OBJ_TYPE);
921 case NF_checkCast:
922 return getNamedFunction("checkCast", MethodType.methodType(Object.class, Object.class, Object.class));
923 case NF_allocateInstance:
924 return getNamedFunction("allocateInstance", OBJ_OBJ_TYPE);
925 case NF_constructorMethod:
926 return getNamedFunction("constructorMethod", OBJ_OBJ_TYPE);
927 case NF_UNSAFE:
928 MemberName member = new MemberName(MethodHandleStatics.class, "UNSAFE", Unsafe.class, REF_getField);
929 return new NamedFunction(
930 MemberName.getFactory()
931 .resolveOrFail(REF_getField, member, DirectMethodHandle.class, NoSuchMethodException.class));
932 case NF_checkReceiver:
933 member = new MemberName(DirectMethodHandle.class, "checkReceiver", OBJ_OBJ_TYPE, REF_invokeVirtual);
934 return new NamedFunction(
935 MemberName.getFactory()
936 .resolveOrFail(REF_invokeVirtual, member, DirectMethodHandle.class, NoSuchMethodException.class));
937 case NF_fieldValueType:
938 return getNamedFunction("fieldValueType", CLS_OBJ_TYPE);
939 case NF_staticFieldValueType:
940 return getNamedFunction("staticFieldValueType", CLS_OBJ_TYPE);
941 default:
942 throw newInternalError("Unknown function: " + func);
943 }
944 } catch (ReflectiveOperationException ex) {
945 throw newInternalError(ex);
946 }
947 }
948
949 private static NamedFunction getNamedFunction(String name, MethodType type)
950 throws ReflectiveOperationException
951 {
952 MemberName member = new MemberName(DirectMethodHandle.class, name, type, REF_invokeStatic);
953 return new NamedFunction(
954 MemberName.getFactory()
955 .resolveOrFail(REF_invokeStatic, member, DirectMethodHandle.class, NoSuchMethodException.class));
956 }
957
958 static {
959 // The Holder class will contain pre-generated DirectMethodHandles resolved
960 // speculatively using MemberName.getFactory().resolveOrNull. However, that
961 // doesn't initialize the class, which subtly breaks inlining etc. By forcing
962 // initialization of the Holder class we avoid these issues.
963 UNSAFE.ensureClassInitialized(Holder.class);
964 }
965
966 /* Placeholder class for DirectMethodHandles generated ahead of time */
967 final class Holder {}
968 }