1 /*
2 * Copyright (c) 2008, 2019, 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.isObjectConstructor())
80 throw new InternalError(member.toString());
81 mtype = mtype.insertParameterTypes(0, refc.asPrimaryType());
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.isIndirect() ? new IndirectStaticAccessor(mtype, lform, member, base, offset)
115 : new InlineStaticAccessor(mtype, lform, member, base, offset);
116 } else {
117 long offset = MethodHandleNatives.objectFieldOffset(member);
118 assert(offset == (int)offset);
119 return member.isIndirect() ? new IndirectAccessor(mtype, lform, member, (int)offset)
120 : new InlineAccessor(mtype, lform, member, (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.isObjectConstructor() && member.getReturnType() == void.class)
132 return makeAllocator(member);
133 return make(member.getDeclaringClass(), member);
134 }
135 private static DirectMethodHandle makeAllocator(MemberName ctor) {
136 assert(ctor.isObjectConstructor() && !ctor.getDeclaringClass().isInlineClass()) : ctor;
137
138 Class<?> instanceClass = ctor.getDeclaringClass();
139 ctor = ctor.asObjectConstructor();
140 assert(ctor.getReferenceKind() == REF_newInvokeSpecial) : ctor;
141 MethodType mtype = ctor.getMethodType().changeReturnType(instanceClass);
142 LambdaForm lform = preparedLambdaForm(ctor);
143 MemberName init = ctor.asSpecial();
144 assert(init.getMethodType().returnType() == void.class);
145 return new Constructor(mtype, lform, ctor, init, instanceClass);
146 }
147
148 @Override
149 BoundMethodHandle rebind() {
150 return BoundMethodHandle.makeReinvoker(this);
151 }
152
153 @Override
154 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
155 assert(this.getClass() == DirectMethodHandle.class); // must override in subclasses
156 return new DirectMethodHandle(mt, lf, member);
157 }
158
159 @Override
160 String internalProperties() {
161 return "\n& DMH.MN="+internalMemberName();
162 }
163
164 //// Implementation methods.
165 @Override
166 @ForceInline
167 MemberName internalMemberName() {
168 return member;
169 }
170
171 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
172
173 /**
174 * Create a LF which can invoke the given method.
175 * Cache and share this structure among all methods with
176 * the same basicType and refKind.
177 */
178 private static LambdaForm preparedLambdaForm(MemberName m, boolean adaptToSpecialIfc) {
179 assert(m.isInvocable()) : m; // call preparedFieldLambdaForm instead
180 MethodType mtype = m.getInvocationType().basicType();
181 assert(!m.isMethodHandleInvoke()) : m;
182 int which;
183 // MemberName.getReferenceKind represents the JVM optimized form of the call
184 // as distinct from the "kind" passed to DMH.make which represents the original
185 // bytecode-equivalent request. Specifically private/final methods that use a direct
186 // call have getReferenceKind adapted to REF_invokeSpecial, even though the actual
187 // invocation mode may be invokevirtual or invokeinterface.
188 switch (m.getReferenceKind()) {
189 case REF_invokeVirtual: which = LF_INVVIRTUAL; break;
190 case REF_invokeStatic: which = LF_INVSTATIC; break;
191 case REF_invokeSpecial: which = LF_INVSPECIAL; break;
192 case REF_invokeInterface: which = LF_INVINTERFACE; break;
193 case REF_newInvokeSpecial: which = LF_NEWINVSPECIAL; break;
194 default: throw new InternalError(m.toString());
195 }
196 if (which == LF_INVSTATIC && shouldBeInitialized(m)) {
197 // precompute the barrier-free version:
198 preparedLambdaForm(mtype, which);
199 which = LF_INVSTATIC_INIT;
200 }
201 if (which == LF_INVSPECIAL && adaptToSpecialIfc) {
202 which = LF_INVSPECIAL_IFC;
203 }
204 LambdaForm lform = preparedLambdaForm(mtype, which);
205 maybeCompile(lform, m);
206 assert(lform.methodType().dropParameterTypes(0, 1)
207 .equals(m.getInvocationType().basicType()))
208 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
209 return lform;
210 }
211
212 private static LambdaForm preparedLambdaForm(MemberName m) {
213 return preparedLambdaForm(m, false);
214 }
215
216 private static LambdaForm preparedLambdaForm(MethodType mtype, int which) {
217 LambdaForm lform = mtype.form().cachedLambdaForm(which);
218 if (lform != null) return lform;
219 lform = makePreparedLambdaForm(mtype, which);
220 return mtype.form().setCachedLambdaForm(which, lform);
221 }
222
223 static LambdaForm makePreparedLambdaForm(MethodType mtype, int which) {
224 boolean needsInit = (which == LF_INVSTATIC_INIT);
225 boolean doesAlloc = (which == LF_NEWINVSPECIAL);
226 boolean needsReceiverCheck = (which == LF_INVINTERFACE ||
227 which == LF_INVSPECIAL_IFC);
228
229 String linkerName;
230 LambdaForm.Kind kind;
231 switch (which) {
232 case LF_INVVIRTUAL: linkerName = "linkToVirtual"; kind = DIRECT_INVOKE_VIRTUAL; break;
233 case LF_INVSTATIC: linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC; break;
234 case LF_INVSTATIC_INIT:linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC_INIT; break;
235 case LF_INVSPECIAL_IFC:linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL_IFC; break;
236 case LF_INVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL; break;
237 case LF_INVINTERFACE: linkerName = "linkToInterface"; kind = DIRECT_INVOKE_INTERFACE; break;
238 case LF_NEWINVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_NEW_INVOKE_SPECIAL; break;
239 default: throw new InternalError("which="+which);
240 }
241
242 MethodType mtypeWithArg = mtype.appendParameterTypes(MemberName.class);
243 if (doesAlloc)
244 mtypeWithArg = mtypeWithArg
245 .insertParameterTypes(0, Object.class) // insert newly allocated obj
246 .changeReturnType(void.class); // <init> returns void
247 MemberName linker = new MemberName(MethodHandle.class, linkerName, mtypeWithArg, REF_invokeStatic);
248 try {
249 linker = IMPL_NAMES.resolveOrFail(REF_invokeStatic, linker, null, NoSuchMethodException.class);
250 } catch (ReflectiveOperationException ex) {
251 throw newInternalError(ex);
252 }
253 final int DMH_THIS = 0;
254 final int ARG_BASE = 1;
255 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
256 int nameCursor = ARG_LIMIT;
257 final int NEW_OBJ = (doesAlloc ? nameCursor++ : -1);
258 final int GET_MEMBER = nameCursor++;
259 final int CHECK_RECEIVER = (needsReceiverCheck ? nameCursor++ : -1);
260 final int LINKER_CALL = nameCursor++;
261 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
262 assert(names.length == nameCursor);
263 if (doesAlloc) {
264 // names = { argx,y,z,... new C, init method }
265 names[NEW_OBJ] = new Name(getFunction(NF_allocateInstance), names[DMH_THIS]);
266 names[GET_MEMBER] = new Name(getFunction(NF_constructorMethod), names[DMH_THIS]);
267 } else if (needsInit) {
268 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberNameEnsureInit), names[DMH_THIS]);
269 } else {
270 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberName), names[DMH_THIS]);
271 }
272 assert(findDirectMethodHandle(names[GET_MEMBER]) == names[DMH_THIS]);
273 Object[] outArgs = Arrays.copyOfRange(names, ARG_BASE, GET_MEMBER+1, Object[].class);
274 if (needsReceiverCheck) {
275 names[CHECK_RECEIVER] = new Name(getFunction(NF_checkReceiver), names[DMH_THIS], names[ARG_BASE]);
276 outArgs[0] = names[CHECK_RECEIVER];
277 }
278 assert(outArgs[outArgs.length-1] == names[GET_MEMBER]); // look, shifted args!
279 int result = LAST_RESULT;
280 if (doesAlloc) {
281 assert(outArgs[outArgs.length-2] == names[NEW_OBJ]); // got to move this one
282 System.arraycopy(outArgs, 0, outArgs, 1, outArgs.length-2);
283 outArgs[0] = names[NEW_OBJ];
284 result = NEW_OBJ;
285 }
286 names[LINKER_CALL] = new Name(linker, outArgs);
287 LambdaForm lform = new LambdaForm(ARG_LIMIT, names, result, kind);
288
289 // This is a tricky bit of code. Don't send it through the LF interpreter.
290 lform.compileToBytecode();
291 return lform;
292 }
293
294 /* assert */ static Object findDirectMethodHandle(Name name) {
295 if (name.function.equals(getFunction(NF_internalMemberName)) ||
296 name.function.equals(getFunction(NF_internalMemberNameEnsureInit)) ||
297 name.function.equals(getFunction(NF_constructorMethod))) {
298 assert(name.arguments.length == 1);
299 return name.arguments[0];
300 }
301 return null;
302 }
303
304 private static void maybeCompile(LambdaForm lform, MemberName m) {
305 if (lform.vmentry == null && VerifyAccess.isSamePackage(m.getDeclaringClass(), MethodHandle.class))
306 // Help along bootstrapping...
307 lform.compileToBytecode();
308 }
309
310 /** Static wrapper for DirectMethodHandle.internalMemberName. */
311 @ForceInline
312 /*non-public*/ static Object internalMemberName(Object mh) {
313 return ((DirectMethodHandle)mh).member;
314 }
315
316 /** Static wrapper for DirectMethodHandle.internalMemberName.
317 * This one also forces initialization.
318 */
319 /*non-public*/ static Object internalMemberNameEnsureInit(Object mh) {
320 DirectMethodHandle dmh = (DirectMethodHandle)mh;
321 dmh.ensureInitialized();
322 return dmh.member;
323 }
324
325 /*non-public*/ static
326 boolean shouldBeInitialized(MemberName member) {
327 switch (member.getReferenceKind()) {
328 case REF_invokeStatic:
329 case REF_getStatic:
330 case REF_putStatic:
331 case REF_newInvokeSpecial:
332 break;
333 default:
334 // No need to initialize the class on this kind of member.
335 return false;
336 }
337 Class<?> cls = member.getDeclaringClass();
338 if (cls == ValueConversions.class ||
339 cls == MethodHandleImpl.class ||
340 cls == Invokers.class) {
341 // These guys have lots of <clinit> DMH creation but we know
342 // the MHs will not be used until the system is booted.
343 return false;
344 }
345 if (VerifyAccess.isSamePackage(MethodHandle.class, cls) ||
346 VerifyAccess.isSamePackage(ValueConversions.class, cls)) {
347 // It is a system class. It is probably in the process of
348 // being initialized, but we will help it along just to be safe.
349 if (UNSAFE.shouldBeInitialized(cls)) {
350 UNSAFE.ensureClassInitialized(cls);
351 }
352 return false;
353 }
354 return UNSAFE.shouldBeInitialized(cls);
355 }
356
357 private static class EnsureInitialized extends ClassValue<WeakReference<Thread>> {
358 @Override
359 protected WeakReference<Thread> computeValue(Class<?> type) {
360 UNSAFE.ensureClassInitialized(type);
361 if (UNSAFE.shouldBeInitialized(type))
362 // If the previous call didn't block, this can happen.
363 // We are executing inside <clinit>.
364 return new WeakReference<>(Thread.currentThread());
365 return null;
366 }
367 static final EnsureInitialized INSTANCE = new EnsureInitialized();
368 }
369
370 private void ensureInitialized() {
371 if (checkInitialized(member)) {
372 // The coast is clear. Delete the <clinit> barrier.
373 if (member.isField())
374 updateForm(preparedFieldLambdaForm(member));
375 else
376 updateForm(preparedLambdaForm(member));
377 }
378 }
379 private static boolean checkInitialized(MemberName member) {
380 Class<?> defc = member.getDeclaringClass();
381 WeakReference<Thread> ref = EnsureInitialized.INSTANCE.get(defc);
382 if (ref == null) {
383 return true; // the final state
384 }
385 Thread clinitThread = ref.get();
386 // Somebody may still be running defc.<clinit>.
387 if (clinitThread == Thread.currentThread()) {
388 // If anybody is running defc.<clinit>, it is this thread.
389 if (UNSAFE.shouldBeInitialized(defc))
390 // Yes, we are running it; keep the barrier for now.
391 return false;
392 } else {
393 // We are in a random thread. Block.
394 UNSAFE.ensureClassInitialized(defc);
395 }
396 assert(!UNSAFE.shouldBeInitialized(defc));
397 // put it into the final state
398 EnsureInitialized.INSTANCE.remove(defc);
399 return true;
400 }
401
402 /*non-public*/ static void ensureInitialized(Object mh) {
403 ((DirectMethodHandle)mh).ensureInitialized();
404 }
405
406 /** This subclass represents invokespecial instructions. */
407 static class Special extends DirectMethodHandle {
408 private final Class<?> caller;
409 private Special(MethodType mtype, LambdaForm form, MemberName member, Class<?> caller) {
410 super(mtype, form, member);
411 this.caller = caller;
412 }
413 @Override
414 boolean isInvokeSpecial() {
415 return true;
416 }
417 @Override
418 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
419 return new Special(mt, lf, member, caller);
420 }
421 Object checkReceiver(Object recv) {
422 if (!caller.isInstance(recv)) {
423 String msg = String.format("Receiver class %s is not a subclass of caller class %s",
424 recv.getClass().getName(), caller.getName());
425 throw new IncompatibleClassChangeError(msg);
426 }
427 return recv;
428 }
429 }
430
431 /** This subclass represents invokeinterface instructions. */
432 static class Interface extends DirectMethodHandle {
433 private final Class<?> refc;
434 private Interface(MethodType mtype, LambdaForm form, MemberName member, Class<?> refc) {
435 super(mtype, form, member);
436 assert refc.isInterface() : refc;
437 this.refc = refc;
438 }
439 @Override
440 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
441 return new Interface(mt, lf, member, refc);
442 }
443 @Override
444 Object checkReceiver(Object recv) {
445 if (!refc.isInstance(recv)) {
446 String msg = String.format("Receiver class %s does not implement the requested interface %s",
447 recv.getClass().getName(), refc.getName());
448 throw new IncompatibleClassChangeError(msg);
449 }
450 return recv;
451 }
452 }
453
454 /** Used for interface receiver type checks, by Interface and Special modes. */
455 Object checkReceiver(Object recv) {
456 throw new InternalError("Should only be invoked on a subclass");
457 }
458
459
460 /** This subclass handles constructor references. */
461 static class Constructor extends DirectMethodHandle {
462 final MemberName initMethod;
463 final Class<?> instanceClass;
464
465 private Constructor(MethodType mtype, LambdaForm form, MemberName constructor,
466 MemberName initMethod, Class<?> instanceClass) {
467 super(mtype, form, constructor);
468 this.initMethod = initMethod;
469 this.instanceClass = instanceClass;
470 assert(initMethod.isResolved());
471 }
472 @Override
473 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
474 return new Constructor(mt, lf, member, initMethod, instanceClass);
475 }
476 }
477
478 /*non-public*/ static Object constructorMethod(Object mh) {
479 Constructor dmh = (Constructor)mh;
480 return dmh.initMethod;
481 }
482
483 /*non-public*/ static Object allocateInstance(Object mh) throws InstantiationException {
484 Constructor dmh = (Constructor)mh;
485 return UNSAFE.allocateInstance(dmh.instanceClass);
486 }
487
488 /** This subclass handles non-static field references. */
489 static abstract class Accessor extends DirectMethodHandle {
490 final Class<?> fieldType;
491 final int fieldOffset;
492
493 protected Accessor(MethodType mtype, LambdaForm form, MemberName member,
494 int fieldOffset) {
495 super(mtype, form, member);
496 this.fieldType = member.getFieldType();
497 this.fieldOffset = fieldOffset;
498 }
499 abstract Object checkCast(Object obj);
500 abstract MethodHandle copyWith(MethodType mt, LambdaForm lf);
501 }
502
503 /** This subclass handles non-static field references of indirect type */
504 static class IndirectAccessor extends Accessor {
505 private IndirectAccessor(MethodType mtype, LambdaForm form, MemberName member,
506 int fieldOffset) {
507 super(mtype, form, member, fieldOffset);
508 }
509
510 @Override Object checkCast(Object obj) {
511 return fieldType.cast(obj);
512 }
513 @Override
514 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
515 return new IndirectAccessor(mt, lf, member, fieldOffset);
516 }
517 }
518
519 /** This subclass handles non-static field references of inline type */
520 static class InlineAccessor extends Accessor {
521 private InlineAccessor(MethodType mtype, LambdaForm form, MemberName member,
522 int fieldOffset) {
523 super(mtype, form, member, fieldOffset);
524 }
525
526 @Override Object checkCast(Object obj) {
527 return fieldType.cast(Objects.requireNonNull(obj));
528 }
529 @Override
530 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
531 return new InlineAccessor(mt, lf, member, fieldOffset);
532 }
533 }
534
535 @ForceInline
536 /*non-public*/ static long fieldOffset(Object accessorObj) {
537 // Note: We return a long because that is what Unsafe.getObject likes.
538 // We store a plain int because it is more compact.
539 return ((Accessor)accessorObj).fieldOffset;
540 }
541
542 @ForceInline
543 /*non-public*/ static Object checkBase(Object obj) {
544 // Note that the object's class has already been verified,
545 // since the parameter type of the Accessor method handle
546 // is either member.getDeclaringClass or a subclass.
547 // This was verified in DirectMethodHandle.make.
548 // Therefore, the only remaining check is for null.
549 // Since this check is *not* guaranteed by Unsafe.getInt
550 // and its siblings, we need to make an explicit one here.
551 return Objects.requireNonNull(obj);
552 }
553
554 static abstract class StaticAccessor extends DirectMethodHandle {
555 final Class<?> fieldType;
556 final Object staticBase;
557 final long staticOffset;
558
559 protected StaticAccessor(MethodType mtype, LambdaForm form, MemberName member,
560 Object staticBase, long staticOffset) {
561 super(mtype, form, member);
562 this.fieldType = member.getFieldType();
563 this.staticBase = staticBase;
564 this.staticOffset = staticOffset;
565 }
566 abstract Object checkCast(Object obj);
567 abstract MethodHandle copyWith(MethodType mt, LambdaForm lf);
568 }
569
570 /** This subclass handles static field references of indirect type. */
571 static class IndirectStaticAccessor extends StaticAccessor {
572 private IndirectStaticAccessor(MethodType mtype, LambdaForm form, MemberName member,
573 Object staticBase, long staticOffset) {
574 super(mtype, form, member, staticBase, staticOffset);
575 }
576
577 // indirect type is always nullable
578 @Override Object checkCast(Object obj) {
579 return fieldType.cast(obj);
580 }
581 @Override
582 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
583 return new IndirectStaticAccessor(mt, lf, member, staticBase, staticOffset);
584 }
585 }
586
587 /** This subclass handles static field references of inline type . */
588 static class InlineStaticAccessor extends StaticAccessor {
589 private InlineStaticAccessor(MethodType mtype, LambdaForm form, MemberName member,
590 Object staticBase, long staticOffset) {
591 super(mtype, form, member, staticBase, staticOffset);
592 }
593
594 // zero-default inline type is not-nullable
595 @Override Object checkCast(Object obj) {
596 assert !fieldType.isNullableType() : "null-default inline type not yet supported";
597 return fieldType.cast(Objects.requireNonNull(obj));
598 }
599 @Override
600 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
601 return new InlineStaticAccessor(mt, lf, member, staticBase, staticOffset);
602 }
603 }
604
605 @ForceInline
606 /*non-public*/ static Object nullCheck(Object obj) {
607 return Objects.requireNonNull(obj);
608 }
609
610 @ForceInline
611 /*non-public*/ static Object staticBase(Object accessorObj) {
612 return ((StaticAccessor)accessorObj).staticBase;
613 }
614
615 @ForceInline
616 /*non-public*/ static long staticOffset(Object accessorObj) {
617 return ((StaticAccessor)accessorObj).staticOffset;
618 }
619
620 @ForceInline
621 /*non-public*/ static Object checkCast(Object mh, Object obj) {
622 return ((DirectMethodHandle) mh).checkCast(obj);
623 }
624
625 @ForceInline
626 /*non-public*/ static Class<?> fieldType(Object accessorObj) {
627 return ((Accessor) accessorObj).fieldType;
628 }
629
630 @ForceInline
631 /*non-public*/ static Class<?> staticFieldType(Object accessorObj) {
632 return ((StaticAccessor) accessorObj).fieldType;
633 }
634
635 Object checkCast(Object obj) {
636 return member.getReturnType().cast(obj);
637 }
638
639 // Caching machinery for field accessors:
640 static final byte
641 AF_GETFIELD = 0,
642 AF_PUTFIELD = 1,
643 AF_GETSTATIC = 2,
644 AF_PUTSTATIC = 3,
645 AF_GETSTATIC_INIT = 4,
646 AF_PUTSTATIC_INIT = 5,
647 AF_LIMIT = 6;
648 // Enumerate the different field kinds using Wrapper,
649 // with an extra case added for checked references and value field access
650 static final int
651 FT_LAST_WRAPPER = Wrapper.COUNT-1,
652 FT_UNCHECKED_REF = Wrapper.OBJECT.ordinal(),
653 FT_CHECKED_REF = FT_LAST_WRAPPER+1,
654 FT_CHECKED_VALUE = FT_LAST_WRAPPER+2, // flattened and non-flattened
655 FT_LIMIT = FT_LAST_WRAPPER+4;
656 private static int afIndex(byte formOp, boolean isVolatile, boolean isFlatValue, int ftypeKind) {
657 return ((formOp * FT_LIMIT * 2)
658 + (isVolatile ? FT_LIMIT : 0)
659 + (isFlatValue ? 1 : 0)
660 + ftypeKind);
661 }
662 @Stable
663 private static final LambdaForm[] ACCESSOR_FORMS
664 = new LambdaForm[afIndex(AF_LIMIT, false, false, 0)];
665 static int ftypeKind(Class<?> ftype, boolean isValue) {
666 if (ftype.isPrimitive())
667 return Wrapper.forPrimitiveType(ftype).ordinal();
668 else if (VerifyType.isNullReferenceConversion(Object.class, ftype)) {
669 return FT_UNCHECKED_REF;
670 } else
671 // null check for value type in addition to check cast
672 return isValue ? FT_CHECKED_VALUE : FT_CHECKED_REF;
673 }
674
675 /**
676 * Create a LF which can access the given field.
677 * Cache and share this structure among all fields with
678 * the same basicType and refKind.
679 */
680 private static LambdaForm preparedFieldLambdaForm(MemberName m) {
681 Class<?> ftype = m.getFieldType();
682 byte formOp;
683 switch (m.getReferenceKind()) {
684 case REF_getField: formOp = AF_GETFIELD; break;
685 case REF_putField: formOp = AF_PUTFIELD; break;
686 case REF_getStatic: formOp = AF_GETSTATIC; break;
687 case REF_putStatic: formOp = AF_PUTSTATIC; break;
688 default: throw new InternalError(m.toString());
689 }
690 if (shouldBeInitialized(m)) {
691 // precompute the barrier-free version:
692 preparedFieldLambdaForm(formOp, m.isVolatile(), m.isInlineable(), m.isFlattened(), ftype);
693 assert((AF_GETSTATIC_INIT - AF_GETSTATIC) ==
694 (AF_PUTSTATIC_INIT - AF_PUTSTATIC));
695 formOp += (AF_GETSTATIC_INIT - AF_GETSTATIC);
696 }
697 LambdaForm lform = preparedFieldLambdaForm(formOp, m.isVolatile(), m.isInlineable(), m.isFlattened(), ftype);
698 maybeCompile(lform, m);
699 assert(lform.methodType().dropParameterTypes(0, 1)
700 .equals(m.getInvocationType().basicType()))
701 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
702 return lform;
703 }
704
705 private static LambdaForm preparedFieldLambdaForm(byte formOp, boolean isVolatile, boolean isValue, boolean isFlatValue, Class<?> ftype) {
706 int ftypeKind = ftypeKind(ftype, isValue);
707 int afIndex = afIndex(formOp, isVolatile, isFlatValue, ftypeKind);
708 LambdaForm lform = ACCESSOR_FORMS[afIndex];
709 if (lform != null) return lform;
710 lform = makePreparedFieldLambdaForm(formOp, isVolatile, isValue, isFlatValue, ftypeKind);
711 ACCESSOR_FORMS[afIndex] = lform; // don't bother with a CAS
712 return lform;
713 }
714
715 private static final Wrapper[] ALL_WRAPPERS = Wrapper.values();
716
717 private static Kind getFieldKind(boolean isGetter, boolean isVolatile, boolean isFlatValue, Wrapper wrapper) {
718 if (isGetter) {
719 if (isVolatile) {
720 switch (wrapper) {
721 case BOOLEAN: return GET_BOOLEAN_VOLATILE;
722 case BYTE: return GET_BYTE_VOLATILE;
723 case SHORT: return GET_SHORT_VOLATILE;
724 case CHAR: return GET_CHAR_VOLATILE;
725 case INT: return GET_INT_VOLATILE;
726 case LONG: return GET_LONG_VOLATILE;
727 case FLOAT: return GET_FLOAT_VOLATILE;
728 case DOUBLE: return GET_DOUBLE_VOLATILE;
729 case OBJECT: return isFlatValue ? GET_VALUE_VOLATILE : GET_REFERENCE_VOLATILE;
730 }
731 } else {
732 switch (wrapper) {
733 case BOOLEAN: return GET_BOOLEAN;
734 case BYTE: return GET_BYTE;
735 case SHORT: return GET_SHORT;
736 case CHAR: return GET_CHAR;
737 case INT: return GET_INT;
738 case LONG: return GET_LONG;
739 case FLOAT: return GET_FLOAT;
740 case DOUBLE: return GET_DOUBLE;
741 case OBJECT: return isFlatValue ? GET_VALUE : GET_REFERENCE;
742 }
743 }
744 } else {
745 if (isVolatile) {
746 switch (wrapper) {
747 case BOOLEAN: return PUT_BOOLEAN_VOLATILE;
748 case BYTE: return PUT_BYTE_VOLATILE;
749 case SHORT: return PUT_SHORT_VOLATILE;
750 case CHAR: return PUT_CHAR_VOLATILE;
751 case INT: return PUT_INT_VOLATILE;
752 case LONG: return PUT_LONG_VOLATILE;
753 case FLOAT: return PUT_FLOAT_VOLATILE;
754 case DOUBLE: return PUT_DOUBLE_VOLATILE;
755 case OBJECT: return isFlatValue ? PUT_VALUE_VOLATILE : PUT_REFERENCE_VOLATILE;
756 }
757 } else {
758 switch (wrapper) {
759 case BOOLEAN: return PUT_BOOLEAN;
760 case BYTE: return PUT_BYTE;
761 case SHORT: return PUT_SHORT;
762 case CHAR: return PUT_CHAR;
763 case INT: return PUT_INT;
764 case LONG: return PUT_LONG;
765 case FLOAT: return PUT_FLOAT;
766 case DOUBLE: return PUT_DOUBLE;
767 case OBJECT: return isFlatValue ? PUT_VALUE : PUT_REFERENCE;
768 }
769 }
770 }
771 throw new AssertionError("Invalid arguments");
772 }
773
774 /** invoked by GenerateJLIClassesHelper */
775 static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, int ftype) {
776 return makePreparedFieldLambdaForm(formOp, isVolatile, false, false, ftype);
777 }
778
779 private static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, boolean isValue, boolean isFlatValue, int ftypeKind) {
780 boolean isGetter = (formOp & 1) == (AF_GETFIELD & 1);
781 boolean isStatic = (formOp >= AF_GETSTATIC);
782 boolean needsInit = (formOp >= AF_GETSTATIC_INIT);
783 boolean needsCast = (ftypeKind == FT_CHECKED_REF || ftypeKind == FT_CHECKED_VALUE);
784 Wrapper fw = (needsCast ? Wrapper.OBJECT : ALL_WRAPPERS[ftypeKind]);
785 Class<?> ft = fw.primitiveType();
786 assert(needsCast ? true : ftypeKind(ft, isValue) == ftypeKind);
787
788 // getObject, putIntVolatile, etc.
789 Kind kind = getFieldKind(isGetter, isVolatile, isFlatValue, fw);
790
791 MethodType linkerType;
792 boolean hasValueTypeArg = isGetter ? isValue : isFlatValue;
793 if (isGetter) {
794 linkerType = isValue ? MethodType.methodType(ft, Object.class, long.class, Class.class)
795 : MethodType.methodType(ft, Object.class, long.class);
796 } else {
797 linkerType = isFlatValue ? MethodType.methodType(void.class, Object.class, long.class, Class.class, ft)
798 : MethodType.methodType(void.class, Object.class, long.class, ft);
799 }
800 MemberName linker = new MemberName(Unsafe.class, kind.methodName, linkerType, REF_invokeVirtual);
801 try {
802 linker = IMPL_NAMES.resolveOrFail(REF_invokeVirtual, linker, null, NoSuchMethodException.class);
803 } catch (ReflectiveOperationException ex) {
804 throw newInternalError(ex);
805 }
806
807 // What is the external type of the lambda form?
808 MethodType mtype;
809 if (isGetter)
810 mtype = MethodType.methodType(ft);
811 else
812 mtype = MethodType.methodType(void.class, ft);
813 mtype = mtype.basicType(); // erase short to int, etc.
814 if (!isStatic)
815 mtype = mtype.insertParameterTypes(0, Object.class);
816 final int DMH_THIS = 0;
817 final int ARG_BASE = 1;
818 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
819 // if this is for non-static access, the base pointer is stored at this index:
820 final int OBJ_BASE = isStatic ? -1 : ARG_BASE;
821 // if this is for write access, the value to be written is stored at this index:
822 final int SET_VALUE = isGetter ? -1 : ARG_LIMIT - 1;
823 int nameCursor = ARG_LIMIT;
824 final int F_HOLDER = (isStatic ? nameCursor++ : -1); // static base if any
825 final int F_OFFSET = nameCursor++; // Either static offset or field offset.
826 final int OBJ_CHECK = (OBJ_BASE >= 0 ? nameCursor++ : -1);
827 final int U_HOLDER = nameCursor++; // UNSAFE holder
828 final int INIT_BAR = (needsInit ? nameCursor++ : -1);
829 final int VALUE_TYPE = (hasValueTypeArg ? nameCursor++ : -1);
830 final int PRE_CAST = (needsCast && !isGetter ? nameCursor++ : -1);
831 final int LINKER_CALL = nameCursor++;
832 final int POST_CAST = (needsCast && isGetter ? nameCursor++ : -1);
833 final int RESULT = nameCursor-1; // either the call or the cast
834 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
835 if (needsInit)
836 names[INIT_BAR] = new Name(getFunction(NF_ensureInitialized), names[DMH_THIS]);
837 if (needsCast && !isGetter)
838 names[PRE_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[SET_VALUE]);
839 Object[] outArgs = new Object[1 + linkerType.parameterCount()];
840 assert (outArgs.length == (isGetter ? 3 : 4) + (hasValueTypeArg ? 1 : 0));
841 outArgs[0] = names[U_HOLDER] = new Name(getFunction(NF_UNSAFE));
842 if (isStatic) {
843 outArgs[1] = names[F_HOLDER] = new Name(getFunction(NF_staticBase), names[DMH_THIS]);
844 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_staticOffset), names[DMH_THIS]);
845 } else {
846 outArgs[1] = names[OBJ_CHECK] = new Name(getFunction(NF_checkBase), names[OBJ_BASE]);
847 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_fieldOffset), names[DMH_THIS]);
848 }
849 int x = 3;
850 if (hasValueTypeArg) {
851 outArgs[x++] = names[VALUE_TYPE] = isStatic ? new Name(getFunction(NF_staticFieldType), names[DMH_THIS])
852 : new Name(getFunction(NF_fieldType), names[DMH_THIS]);
853 }
854 if (!isGetter) {
855 outArgs[x] = (needsCast ? names[PRE_CAST] : names[SET_VALUE]);
856 }
857 for (Object a : outArgs) assert(a != null);
858 names[LINKER_CALL] = new Name(linker, outArgs);
859 if (needsCast && isGetter)
860 names[POST_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[LINKER_CALL]);
861 for (Name n : names) assert(n != null);
862
863 LambdaForm form;
864 if (needsCast || needsInit) {
865 // can't use the pre-generated form when casting and/or initializing
866 form = new LambdaForm(ARG_LIMIT, names, RESULT);
867 } else {
868 form = new LambdaForm(ARG_LIMIT, names, RESULT, kind);
869 }
870
871 if (LambdaForm.debugNames()) {
872 // add some detail to the lambdaForm debugname,
873 // significant only for debugging
874 StringBuilder nameBuilder = new StringBuilder(kind.methodName);
875 if (isStatic) {
876 nameBuilder.append("Static");
877 } else {
878 nameBuilder.append("Field");
879 }
880 if (needsCast) {
881 nameBuilder.append("Cast");
882 }
883 if (needsInit) {
884 nameBuilder.append("Init");
885 }
886 LambdaForm.associateWithDebugName(form, nameBuilder.toString());
887 }
888 return form;
889 }
890
891 /**
892 * Pre-initialized NamedFunctions for bootstrapping purposes.
893 */
894 static final byte NF_internalMemberName = 0,
895 NF_internalMemberNameEnsureInit = 1,
896 NF_ensureInitialized = 2,
897 NF_fieldOffset = 3,
898 NF_checkBase = 4,
899 NF_staticBase = 5,
900 NF_staticOffset = 6,
901 NF_checkCast = 7,
902 NF_allocateInstance = 8,
903 NF_constructorMethod = 9,
904 NF_UNSAFE = 10,
905 NF_checkReceiver = 11,
906 NF_fieldType = 12,
907 NF_staticFieldType = 13,
908 NF_LIMIT = 14;
909
910 private static final @Stable NamedFunction[] NFS = new NamedFunction[NF_LIMIT];
911
912 private static NamedFunction getFunction(byte func) {
913 NamedFunction nf = NFS[func];
914 if (nf != null) {
915 return nf;
916 }
917 // Each nf must be statically invocable or we get tied up in our bootstraps.
918 nf = NFS[func] = createFunction(func);
919 assert(InvokerBytecodeGenerator.isStaticallyInvocable(nf));
920 return nf;
921 }
922
923 private static final MethodType CLS_OBJ_TYPE = MethodType.methodType(Class.class, Object.class);
924
925 private static final MethodType OBJ_OBJ_TYPE = MethodType.methodType(Object.class, Object.class);
926
927 private static final MethodType LONG_OBJ_TYPE = MethodType.methodType(long.class, Object.class);
928
929 private static NamedFunction createFunction(byte func) {
930 try {
931 switch (func) {
932 case NF_internalMemberName:
933 return getNamedFunction("internalMemberName", OBJ_OBJ_TYPE);
934 case NF_internalMemberNameEnsureInit:
935 return getNamedFunction("internalMemberNameEnsureInit", OBJ_OBJ_TYPE);
936 case NF_ensureInitialized:
937 return getNamedFunction("ensureInitialized", MethodType.methodType(void.class, Object.class));
938 case NF_fieldOffset:
939 return getNamedFunction("fieldOffset", LONG_OBJ_TYPE);
940 case NF_checkBase:
941 return getNamedFunction("checkBase", OBJ_OBJ_TYPE);
942 case NF_staticBase:
943 return getNamedFunction("staticBase", OBJ_OBJ_TYPE);
944 case NF_staticOffset:
945 return getNamedFunction("staticOffset", LONG_OBJ_TYPE);
946 case NF_checkCast:
947 return getNamedFunction("checkCast", MethodType.methodType(Object.class, Object.class, Object.class));
948 case NF_allocateInstance:
949 return getNamedFunction("allocateInstance", OBJ_OBJ_TYPE);
950 case NF_constructorMethod:
951 return getNamedFunction("constructorMethod", OBJ_OBJ_TYPE);
952 case NF_UNSAFE:
953 MemberName member = new MemberName(MethodHandleStatics.class, "UNSAFE", Unsafe.class, REF_getField);
954 return new NamedFunction(
955 MemberName.getFactory()
956 .resolveOrFail(REF_getField, member, DirectMethodHandle.class, NoSuchMethodException.class));
957 case NF_checkReceiver:
958 member = new MemberName(DirectMethodHandle.class, "checkReceiver", OBJ_OBJ_TYPE, REF_invokeVirtual);
959 return new NamedFunction(
960 MemberName.getFactory()
961 .resolveOrFail(REF_invokeVirtual, member, DirectMethodHandle.class, NoSuchMethodException.class));
962 case NF_fieldType:
963 return getNamedFunction("fieldType", CLS_OBJ_TYPE);
964 case NF_staticFieldType:
965 return getNamedFunction("staticFieldType", CLS_OBJ_TYPE);
966 default:
967 throw newInternalError("Unknown function: " + func);
968 }
969 } catch (ReflectiveOperationException ex) {
970 throw newInternalError(ex);
971 }
972 }
973
974 private static NamedFunction getNamedFunction(String name, MethodType type)
975 throws ReflectiveOperationException
976 {
977 MemberName member = new MemberName(DirectMethodHandle.class, name, type, REF_invokeStatic);
978 return new NamedFunction(
979 MemberName.getFactory()
980 .resolveOrFail(REF_invokeStatic, member, DirectMethodHandle.class, NoSuchMethodException.class));
981 }
982
983 static {
984 // The Holder class will contain pre-generated DirectMethodHandles resolved
985 // speculatively using MemberName.getFactory().resolveOrNull. However, that
986 // doesn't initialize the class, which subtly breaks inlining etc. By forcing
987 // initialization of the Holder class we avoid these issues.
988 UNSAFE.ensureClassInitialized(Holder.class);
989 }
990
991 /* Placeholder class for DirectMethodHandles generated ahead of time */
992 final class Holder {}
993 }