1 /*
2 * Copyright (c) 2008, 2025, 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.CDS;
29 import jdk.internal.misc.Unsafe;
30 import jdk.internal.vm.annotation.ForceInline;
31 import jdk.internal.vm.annotation.Stable;
32 import sun.invoke.util.ValueConversions;
33 import sun.invoke.util.VerifyAccess;
34 import sun.invoke.util.Wrapper;
35
36 import java.util.Arrays;
37 import java.util.Objects;
38 import java.util.function.Function;
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 sealed 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, LM_TRUSTED);
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 return 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 yield 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 yield new Interface(mtype, lform, member, true, refc);
105 }
106 default -> {
107 LambdaForm lform = preparedLambdaForm(member);
108 yield 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.getDeclaringClass(), member);
133 return make(member.getDeclaringClass(), member);
134 }
135 static DirectMethodHandle makeAllocator(Class<?> instanceClass, MemberName ctor) {
136 assert(ctor.isConstructor()) : ctor;
137 ctor = ctor.asConstructor();
138 assert(ctor.getReferenceKind() == REF_newInvokeSpecial) : ctor;
139 MethodType mtype = ctor.getMethodType().changeReturnType(instanceClass);
140 LambdaForm lform = preparedLambdaForm(ctor);
141 MemberName init = ctor.asSpecial();
142 assert(init.getMethodType().returnType() == void.class);
143 return new Constructor(mtype, lform, ctor, true, init, instanceClass);
144 }
145
146 @Override
147 BoundMethodHandle rebind() {
148 return BoundMethodHandle.makeReinvoker(this);
149 }
150
151 @Override
152 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
153 assert(this.getClass() == DirectMethodHandle.class); // must override in subclasses
154 return new DirectMethodHandle(mt, lf, member, crackable);
155 }
156
157 @Override
158 MethodHandle viewAsType(MethodType newType, boolean strict) {
159 // No actual conversions, just a new view of the same method.
160 // However, we must not expose a DMH that is crackable into a
161 // MethodHandleInfo, so we return a cloned, uncrackable DMH
162 assert(viewAsTypeChecks(newType, strict));
163 assert(this.getClass() == DirectMethodHandle.class); // must override in subclasses
164 return new DirectMethodHandle(newType, form, member, false);
165 }
166
167 @Override
168 boolean isCrackable() {
169 return crackable;
170 }
171
172 @Override
173 String internalProperties(int indentLevel) {
174 return "\n" + debugPrefix(indentLevel) + "& DMH.MN=" + internalMemberName();
175 }
176
177 //// Implementation methods.
178 @Override
179 @ForceInline
180 MemberName internalMemberName() {
181 return member;
182 }
183
184 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
185
186 /**
187 * Create a LF which can invoke the given method.
188 * Cache and share this structure among all methods with
189 * the same basicType and refKind.
190 */
191 private static LambdaForm preparedLambdaForm(MemberName m, boolean adaptToSpecialIfc) {
192 assert(m.isInvocable()) : m; // call preparedFieldLambdaForm instead
193 MethodType mtype = m.getInvocationType().basicType();
194 assert(!m.isMethodHandleInvoke()) : m;
195 // MemberName.getReferenceKind represents the JVM optimized form of the call
196 // as distinct from the "kind" passed to DMH.make which represents the original
197 // bytecode-equivalent request. Specifically private/final methods that use a direct
198 // call have getReferenceKind adapted to REF_invokeSpecial, even though the actual
199 // invocation mode may be invokevirtual or invokeinterface.
200 int which = switch (m.getReferenceKind()) {
201 case REF_invokeVirtual -> LF_INVVIRTUAL;
202 case REF_invokeStatic -> LF_INVSTATIC;
203 case REF_invokeSpecial -> LF_INVSPECIAL;
204 case REF_invokeInterface -> LF_INVINTERFACE;
205 case REF_newInvokeSpecial -> LF_NEWINVSPECIAL;
206 default -> throw new InternalError(m.toString());
207 };
208 if (which == LF_INVSTATIC && shouldBeInitialized(m)) {
209 // precompute the barrier-free version:
210 preparedLambdaForm(mtype, which);
211 which = LF_INVSTATIC_INIT;
212 }
213 if (which == LF_INVSPECIAL && adaptToSpecialIfc) {
214 which = LF_INVSPECIAL_IFC;
215 }
216 LambdaForm lform = preparedLambdaForm(mtype, which);
217 maybeCompile(lform, m);
218 assert(lform.methodType().dropParameterTypes(0, 1)
219 .equals(m.getInvocationType().basicType()))
220 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
221 return lform;
222 }
223
224 private static LambdaForm preparedLambdaForm(MemberName m) {
225 return preparedLambdaForm(m, false);
226 }
227
228 private static LambdaForm preparedLambdaForm(MethodType mtype, int which) {
229 LambdaForm lform = mtype.form().cachedLambdaForm(which);
230 if (lform != null) return lform;
231 lform = makePreparedLambdaForm(mtype, which);
232 return mtype.form().setCachedLambdaForm(which, lform);
233 }
234
235 static LambdaForm makePreparedLambdaForm(MethodType mtype, int which) {
236 boolean needsInit = (which == LF_INVSTATIC_INIT);
237 boolean doesAlloc = (which == LF_NEWINVSPECIAL);
238 boolean needsReceiverCheck = (which == LF_INVINTERFACE ||
239 which == LF_INVSPECIAL_IFC);
240
241 String linkerName;
242 LambdaForm.Kind kind;
243 switch (which) {
244 case LF_INVVIRTUAL: linkerName = "linkToVirtual"; kind = DIRECT_INVOKE_VIRTUAL; break;
245 case LF_INVSTATIC: linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC; break;
246 case LF_INVSTATIC_INIT:linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC_INIT; break;
247 case LF_INVSPECIAL_IFC:linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL_IFC; break;
248 case LF_INVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL; break;
249 case LF_INVINTERFACE: linkerName = "linkToInterface"; kind = DIRECT_INVOKE_INTERFACE; break;
250 case LF_NEWINVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_NEW_INVOKE_SPECIAL; break;
251 default: throw new InternalError("which="+which);
252 }
253
254 MethodType mtypeWithArg;
255 if (doesAlloc) {
256 var ptypes = mtype.ptypes();
257 var newPtypes = new Class<?>[ptypes.length + 2];
258 newPtypes[0] = Object.class; // insert newly allocated obj
259 System.arraycopy(ptypes, 0, newPtypes, 1, ptypes.length);
260 newPtypes[newPtypes.length - 1] = MemberName.class;
261 mtypeWithArg = MethodType.methodType(void.class, newPtypes, true);
262 } else {
263 mtypeWithArg = mtype.appendParameterTypes(MemberName.class);
264 }
265 MemberName linker = new MemberName(MethodHandle.class, linkerName, mtypeWithArg, REF_invokeStatic);
266 try {
267 linker = IMPL_NAMES.resolveOrFail(REF_invokeStatic, linker, null, LM_TRUSTED,
268 NoSuchMethodException.class);
269 } catch (ReflectiveOperationException ex) {
270 throw newInternalError(ex);
271 }
272 final int DMH_THIS = 0;
273 final int ARG_BASE = 1;
274 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
275 int nameCursor = ARG_LIMIT;
276 final int NEW_OBJ = (doesAlloc ? nameCursor++ : -1);
277 final int GET_MEMBER = nameCursor++;
278 final int CHECK_RECEIVER = (needsReceiverCheck ? nameCursor++ : -1);
279 final int LINKER_CALL = nameCursor++;
280 Name[] names = invokeArguments(nameCursor - ARG_LIMIT, mtype);
281 assert(names.length == nameCursor);
282 if (doesAlloc) {
283 // names = { argx,y,z,... new C, init method }
284 names[NEW_OBJ] = new Name(getFunction(NF_allocateInstance), names[DMH_THIS]);
285 names[GET_MEMBER] = new Name(getFunction(NF_constructorMethod), names[DMH_THIS]);
286 } else if (needsInit) {
287 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberNameEnsureInit), names[DMH_THIS]);
288 } else {
289 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberName), names[DMH_THIS]);
290 }
291 assert(findDirectMethodHandle(names[GET_MEMBER]) == names[DMH_THIS]);
292 Object[] outArgs = Arrays.copyOfRange(names, ARG_BASE, GET_MEMBER+1, Object[].class);
293 if (needsReceiverCheck) {
294 names[CHECK_RECEIVER] = new Name(getFunction(NF_checkReceiver), names[DMH_THIS], names[ARG_BASE]);
295 outArgs[0] = names[CHECK_RECEIVER];
296 }
297 assert(outArgs[outArgs.length-1] == names[GET_MEMBER]); // look, shifted args!
298 int result = LAST_RESULT;
299 if (doesAlloc) {
300 assert(outArgs[outArgs.length-2] == names[NEW_OBJ]); // got to move this one
301 System.arraycopy(outArgs, 0, outArgs, 1, outArgs.length-2);
302 outArgs[0] = names[NEW_OBJ];
303 result = NEW_OBJ;
304 }
305 names[LINKER_CALL] = new Name(linker, outArgs);
306 LambdaForm lform = LambdaForm.create(ARG_LIMIT, names, result, kind);
307
308 // This is a tricky bit of code. Don't send it through the LF interpreter.
309 lform.compileToBytecode();
310 return lform;
311 }
312
313 /* assert */ static Object findDirectMethodHandle(Name name) {
314 if (name.function.equals(getFunction(NF_internalMemberName)) ||
315 name.function.equals(getFunction(NF_internalMemberNameEnsureInit)) ||
316 name.function.equals(getFunction(NF_constructorMethod))) {
317 assert(name.arguments.length == 1);
318 return name.arguments[0];
319 }
320 return null;
321 }
322
323 private static void maybeCompile(LambdaForm lform, MemberName m) {
324 if (lform.vmentry == null && VerifyAccess.isSamePackage(m.getDeclaringClass(), MethodHandle.class))
325 // Help along bootstrapping...
326 lform.compileToBytecode();
327 }
328
329 /** Static wrapper for DirectMethodHandle.internalMemberName. */
330 @ForceInline
331 /*non-public*/
332 static Object internalMemberName(Object mh) {
333 return ((DirectMethodHandle)mh).member;
334 }
335
336 /** Static wrapper for DirectMethodHandle.internalMemberName.
337 * This one also forces initialization.
338 */
339 /*non-public*/
340 static Object internalMemberNameEnsureInit(Object mh) {
341 DirectMethodHandle dmh = (DirectMethodHandle)mh;
342 dmh.ensureInitialized();
343 return dmh.member;
344 }
345
346 /*non-public*/
347 static boolean shouldBeInitialized(MemberName member) {
348 switch (member.getReferenceKind()) {
349 case REF_invokeStatic:
350 case REF_getStatic:
351 case REF_putStatic:
352 case REF_newInvokeSpecial:
353 break;
354 default:
355 // No need to initialize the class on this kind of member.
356 return false;
357 }
358 Class<?> cls = member.getDeclaringClass();
359 if (cls == ValueConversions.class ||
360 cls == MethodHandleImpl.class ||
361 cls == Invokers.class) {
362 // These guys have lots of <clinit> DMH creation but we know
363 // the MHs will not be used until the system is booted.
364 return false;
365 }
366 if (VerifyAccess.isSamePackage(MethodHandle.class, cls) ||
367 VerifyAccess.isSamePackage(ValueConversions.class, cls)) {
368 // It is a system class. It is probably in the process of
369 // being initialized, but we will help it along just to be safe.
370 UNSAFE.ensureClassInitialized(cls);
371 return CDS.needsClassInitBarrier(cls);
372 }
373 return UNSAFE.shouldBeInitialized(cls) || CDS.needsClassInitBarrier(cls);
374 }
375
376 private void ensureInitialized() {
377 if (checkInitialized(member)) {
378 // The coast is clear. Delete the <clinit> barrier.
379 updateForm(new Function<>() {
380 public LambdaForm apply(LambdaForm oldForm) {
381 return (member.isField() ? preparedFieldLambdaForm(member)
382 : preparedLambdaForm(member));
383 }
384 });
385 }
386 }
387 private static boolean checkInitialized(MemberName member) {
388 Class<?> defc = member.getDeclaringClass();
389 UNSAFE.ensureClassInitialized(defc);
390 // Once we get here either defc was fully initialized by another thread, or
391 // defc was already being initialized by the current thread. In the latter case
392 // the barrier must remain. We can detect this simply by checking if initialization
393 // is still needed.
394 return !UNSAFE.shouldBeInitialized(defc);
395 }
396
397 /*non-public*/
398 static void ensureInitialized(Object mh) {
399 ((DirectMethodHandle)mh).ensureInitialized();
400 }
401
402 /** This subclass represents invokespecial instructions. */
403 static final class Special extends DirectMethodHandle {
404 private final Class<?> caller;
405 private Special(MethodType mtype, LambdaForm form, MemberName member, boolean crackable, Class<?> caller) {
406 super(mtype, form, member, crackable);
407 this.caller = caller;
408 }
409 @Override
410 boolean isInvokeSpecial() {
411 return true;
412 }
413 @Override
414 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
415 return new Special(mt, lf, member, crackable, caller);
416 }
417 @Override
418 MethodHandle viewAsType(MethodType newType, boolean strict) {
419 assert(viewAsTypeChecks(newType, strict));
420 return new Special(newType, form, member, false, caller);
421 }
422 Object checkReceiver(Object recv) {
423 if (!caller.isInstance(recv)) {
424 if (recv != null) {
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 } else {
429 String msg = String.format("Cannot invoke %s with null receiver", member);
430 throw new NullPointerException(msg);
431 }
432 }
433 return recv;
434 }
435 }
436
437 /** This subclass represents invokeinterface instructions. */
438 static final class Interface extends DirectMethodHandle {
439 private final Class<?> refc;
440 private Interface(MethodType mtype, LambdaForm form, MemberName member, boolean crackable, Class<?> refc) {
441 super(mtype, form, member, crackable);
442 assert(refc.isInterface()) : refc;
443 this.refc = refc;
444 }
445 @Override
446 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
447 return new Interface(mt, lf, member, crackable, refc);
448 }
449 @Override
450 MethodHandle viewAsType(MethodType newType, boolean strict) {
451 assert(viewAsTypeChecks(newType, strict));
452 return new Interface(newType, form, member, false, refc);
453 }
454 @Override
455 Object checkReceiver(Object recv) {
456 if (!refc.isInstance(recv)) {
457 if (recv != null) {
458 String msg = String.format("Receiver class %s does not implement the requested interface %s",
459 recv.getClass().getName(), refc.getName());
460 throw new IncompatibleClassChangeError(msg);
461 } else {
462 String msg = String.format("Cannot invoke %s with null receiver", member);
463 throw new NullPointerException(msg);
464 }
465 }
466 return recv;
467 }
468 }
469
470 /** Used for interface receiver type checks, by Interface and Special modes. */
471 Object checkReceiver(Object recv) {
472 throw new InternalError("Should only be invoked on a subclass");
473 }
474
475 /** This subclass handles constructor references. */
476 static final class Constructor extends DirectMethodHandle {
477 final MemberName initMethod;
478 final Class<?> instanceClass;
479
480 private Constructor(MethodType mtype, LambdaForm form, MemberName constructor,
481 boolean crackable, MemberName initMethod, Class<?> instanceClass) {
482 super(mtype, form, constructor, crackable);
483 this.initMethod = initMethod;
484 this.instanceClass = instanceClass;
485 assert(initMethod.isResolved());
486 }
487 @Override
488 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
489 return new Constructor(mt, lf, member, crackable, initMethod, instanceClass);
490 }
491 @Override
492 MethodHandle viewAsType(MethodType newType, boolean strict) {
493 assert(viewAsTypeChecks(newType, strict));
494 return new Constructor(newType, form, member, false, initMethod, instanceClass);
495 }
496 }
497
498 /*non-public*/
499 static Object constructorMethod(Object mh) {
500 Constructor dmh = (Constructor)mh;
501 return dmh.initMethod;
502 }
503
504 /*non-public*/
505 static Object allocateInstance(Object mh) throws InstantiationException {
506 Constructor dmh = (Constructor)mh;
507 return UNSAFE.allocateInstance(dmh.instanceClass);
508 }
509
510 /** This subclass handles non-static field references. */
511 static final class Accessor extends DirectMethodHandle {
512 final Class<?> fieldType;
513 final int fieldOffset;
514 final int layout;
515 private Accessor(MethodType mtype, LambdaForm form, MemberName member,
516 boolean crackable, int fieldOffset) {
517 super(mtype, form, member, crackable);
518 this.fieldType = member.getFieldType();
519 this.fieldOffset = fieldOffset;
520 this.layout = member.getLayout();
521 }
522
523 @Override Object checkCast(Object obj) {
524 return fieldType.cast(obj);
525 }
526 @Override
527 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
528 return new Accessor(mt, lf, member, crackable, fieldOffset);
529 }
530 @Override
531 MethodHandle viewAsType(MethodType newType, boolean strict) {
532 assert(viewAsTypeChecks(newType, strict));
533 return new Accessor(newType, form, member, false, fieldOffset);
534 }
535 }
536
537 @ForceInline
538 /*non-public*/
539 static long fieldOffset(Object accessorObj) {
540 // Note: We return a long because that is what Unsafe.getObject likes.
541 // We store a plain int because it is more compact.
542 return ((Accessor)accessorObj).fieldOffset;
543 }
544
545 @ForceInline
546 /*non-public*/
547 static Object checkBase(Object obj) {
548 // Note that the object's class has already been verified,
549 // since the parameter type of the Accessor method handle
550 // is either member.getDeclaringClass or a subclass.
551 // This was verified in DirectMethodHandle.make.
552 // Therefore, the only remaining check is for null.
553 // Since this check is *not* guaranteed by Unsafe.getInt
554 // and its siblings, we need to make an explicit one here.
555 return Objects.requireNonNull(obj);
556 }
557
558 /** This subclass handles static field references. */
559 static final class StaticAccessor extends DirectMethodHandle {
560 private final Class<?> fieldType;
561 private final Object staticBase;
562 private final long staticOffset;
563
564 private StaticAccessor(MethodType mtype, LambdaForm form, MemberName member,
565 boolean crackable, Object staticBase, long staticOffset) {
566 super(mtype, form, member, crackable);
567 this.fieldType = member.getFieldType();
568 this.staticBase = staticBase;
569 this.staticOffset = staticOffset;
570 }
571
572 @Override Object checkCast(Object obj) {
573 return fieldType.cast(obj);
574 }
575 @Override
576 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
577 return new StaticAccessor(mt, lf, member, crackable, staticBase, staticOffset);
578 }
579 @Override
580 MethodHandle viewAsType(MethodType newType, boolean strict) {
581 assert(viewAsTypeChecks(newType, strict));
582 return new StaticAccessor(newType, form, member, false, staticBase, staticOffset);
583 }
584 }
585
586 @ForceInline
587 /*non-public*/
588 static Object nullCheck(Object obj) {
589 return Objects.requireNonNull(obj);
590 }
591
592 @ForceInline
593 /*non-public*/
594 static Object staticBase(Object accessorObj) {
595 return ((StaticAccessor)accessorObj).staticBase;
596 }
597
598 @ForceInline
599 /*non-public*/
600 static long staticOffset(Object accessorObj) {
601 return ((StaticAccessor)accessorObj).staticOffset;
602 }
603
604 @ForceInline
605 /*non-public*/
606 static Object checkCast(Object mh, Object obj) {
607 return ((DirectMethodHandle) mh).checkCast(obj);
608 }
609
610 @ForceInline
611 /*non-public*/ static Class<?> fieldType(Object accessorObj) {
612 return ((Accessor) accessorObj).fieldType;
613 }
614
615 @ForceInline
616 static int fieldLayout(Object accessorObj) {
617 return ((Accessor) accessorObj).layout;
618 }
619
620 @ForceInline
621 /*non-public*/ static Class<?> staticFieldType(Object accessorObj) {
622 return ((StaticAccessor) accessorObj).fieldType;
623 }
624
625 Object checkCast(Object obj) {
626 return member.getMethodType().returnType().cast(obj);
627 }
628
629 // Caching machinery for field accessors:
630 static final byte
631 AF_GETFIELD = 0,
632 AF_PUTFIELD = 1,
633 AF_GETSTATIC = 2,
634 AF_PUTSTATIC = 3,
635 AF_GETSTATIC_INIT = 4,
636 AF_PUTSTATIC_INIT = 5,
637 AF_LIMIT = 6;
638 // Enumerate the different field kinds using Wrapper,
639 // with an extra case added for checked references and value field access
640 static final int
641 FT_LAST_WRAPPER = Wrapper.COUNT-1,
642 FT_UNCHECKED_REF = Wrapper.OBJECT.ordinal(),
643 FT_CHECKED_REF = FT_LAST_WRAPPER+1,
644 FT_CHECKED_VALUE = FT_LAST_WRAPPER+2, // flat vs non-flat x null value vs null-restricted value
645 FT_LIMIT = FT_LAST_WRAPPER+6;
646 private static int afIndex(byte formOp, boolean isVolatile, boolean isFlat, boolean isNullRestricted, int ftypeKind) {
647 return ((formOp * FT_LIMIT * 2)
648 + (isVolatile ? FT_LIMIT : 0)
649 + (isFlat ? 1 : 0)
650 + (isNullRestricted ? 1 : 0)
651 + ftypeKind);
652 }
653 @Stable
654 private static final LambdaForm[] ACCESSOR_FORMS
655 = new LambdaForm[afIndex(AF_LIMIT, false, false, false, 0)];
656 static int ftypeKind(Class<?> ftype) {
657 if (ftype.isPrimitive()) {
658 return Wrapper.forPrimitiveType(ftype).ordinal();
659 } else if (ftype.isInterface() || ftype.isAssignableFrom(Object.class)) {
660 // retyping can be done without a cast
661 return FT_UNCHECKED_REF;
662 } else {
663 return ftype.isValue() ? FT_CHECKED_VALUE : FT_CHECKED_REF;
664 }
665 }
666
667 /**
668 * Create a LF which can access the given field.
669 * Cache and share this structure among all fields with
670 * the same basicType and refKind.
671 */
672 private static LambdaForm preparedFieldLambdaForm(MemberName m) {
673 Class<?> ftype = m.getFieldType();
674 byte formOp = switch (m.getReferenceKind()) {
675 case REF_getField -> AF_GETFIELD;
676 case REF_putField -> AF_PUTFIELD;
677 case REF_getStatic -> AF_GETSTATIC;
678 case REF_putStatic -> AF_PUTSTATIC;
679 default -> throw new InternalError(m.toString());
680 };
681 if (shouldBeInitialized(m)) {
682 // precompute the barrier-free version:
683 preparedFieldLambdaForm(formOp, m.isVolatile(), m.isFlat(), m.isNullRestricted(), ftype);
684 assert((AF_GETSTATIC_INIT - AF_GETSTATIC) ==
685 (AF_PUTSTATIC_INIT - AF_PUTSTATIC));
686 formOp += (AF_GETSTATIC_INIT - AF_GETSTATIC);
687 }
688 LambdaForm lform = preparedFieldLambdaForm(formOp, m.isVolatile(), m.isFlat(), m.isNullRestricted(), ftype);
689 maybeCompile(lform, m);
690 assert(lform.methodType().dropParameterTypes(0, 1)
691 .equals(m.getInvocationType().basicType()))
692 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
693 return lform;
694 }
695
696 private static LambdaForm preparedFieldLambdaForm(byte formOp, boolean isVolatile,
697 boolean isFlat, boolean isNullRestricted, Class<?> ftype) {
698 int ftypeKind = ftypeKind(ftype);
699 int afIndex = afIndex(formOp, isVolatile, isFlat, isNullRestricted, ftypeKind);
700 LambdaForm lform = ACCESSOR_FORMS[afIndex];
701 if (lform != null) return lform;
702 lform = makePreparedFieldLambdaForm(formOp, isVolatile,isFlat, isNullRestricted, ftypeKind);
703 ACCESSOR_FORMS[afIndex] = lform; // don't bother with a CAS
704 return lform;
705 }
706
707 private static final Wrapper[] ALL_WRAPPERS = Wrapper.values();
708
709 private static Kind getFieldKind(boolean isGetter, boolean isVolatile, boolean isFlat, Wrapper wrapper) {
710 if (isGetter) {
711 if (isVolatile) {
712 switch (wrapper) {
713 case BOOLEAN: return GET_BOOLEAN_VOLATILE;
714 case BYTE: return GET_BYTE_VOLATILE;
715 case SHORT: return GET_SHORT_VOLATILE;
716 case CHAR: return GET_CHAR_VOLATILE;
717 case INT: return GET_INT_VOLATILE;
718 case LONG: return GET_LONG_VOLATILE;
719 case FLOAT: return GET_FLOAT_VOLATILE;
720 case DOUBLE: return GET_DOUBLE_VOLATILE;
721 case OBJECT: return isFlat ? GET_FLAT_VALUE_VOLATILE : GET_REFERENCE_VOLATILE;
722 }
723 } else {
724 switch (wrapper) {
725 case BOOLEAN: return GET_BOOLEAN;
726 case BYTE: return GET_BYTE;
727 case SHORT: return GET_SHORT;
728 case CHAR: return GET_CHAR;
729 case INT: return GET_INT;
730 case LONG: return GET_LONG;
731 case FLOAT: return GET_FLOAT;
732 case DOUBLE: return GET_DOUBLE;
733 case OBJECT: return isFlat ? GET_FLAT_VALUE : GET_REFERENCE;
734 }
735 }
736 } else {
737 if (isVolatile) {
738 switch (wrapper) {
739 case BOOLEAN: return PUT_BOOLEAN_VOLATILE;
740 case BYTE: return PUT_BYTE_VOLATILE;
741 case SHORT: return PUT_SHORT_VOLATILE;
742 case CHAR: return PUT_CHAR_VOLATILE;
743 case INT: return PUT_INT_VOLATILE;
744 case LONG: return PUT_LONG_VOLATILE;
745 case FLOAT: return PUT_FLOAT_VOLATILE;
746 case DOUBLE: return PUT_DOUBLE_VOLATILE;
747 case OBJECT: return isFlat ? PUT_FLAT_VALUE_VOLATILE : PUT_REFERENCE_VOLATILE;
748 }
749 } else {
750 switch (wrapper) {
751 case BOOLEAN: return PUT_BOOLEAN;
752 case BYTE: return PUT_BYTE;
753 case SHORT: return PUT_SHORT;
754 case CHAR: return PUT_CHAR;
755 case INT: return PUT_INT;
756 case LONG: return PUT_LONG;
757 case FLOAT: return PUT_FLOAT;
758 case DOUBLE: return PUT_DOUBLE;
759 case OBJECT: return isFlat ? PUT_FLAT_VALUE : PUT_REFERENCE;
760 }
761 }
762 }
763 throw new AssertionError("Invalid arguments");
764 }
765
766 /** invoked by GenerateJLIClassesHelper */
767 static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, int ftype) {
768 return makePreparedFieldLambdaForm(formOp, isVolatile, false, false, ftype);
769 }
770
771 private static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile,
772 boolean isFlat, boolean isNullRestricted, int ftypeKind) {
773 boolean isGetter = (formOp & 1) == (AF_GETFIELD & 1);
774 boolean isStatic = (formOp >= AF_GETSTATIC);
775 boolean needsInit = (formOp >= AF_GETSTATIC_INIT);
776 boolean needsCast = (ftypeKind == FT_CHECKED_REF || ftypeKind == FT_CHECKED_VALUE);
777 Wrapper fw = (needsCast ? Wrapper.OBJECT : ALL_WRAPPERS[ftypeKind]);
778 Class<?> ft = fw.primitiveType();
779 assert(needsCast ? true : ftypeKind(ft) == ftypeKind);
780
781 // getObject, putIntVolatile, etc.
782 Kind kind = getFieldKind(isGetter, isVolatile, isFlat, fw);
783
784 MethodType linkerType;
785 if (isGetter) {
786 linkerType = isFlat
787 ? MethodType.methodType(ft, Object.class, long.class, int.class, Class.class)
788 : MethodType.methodType(ft, Object.class, long.class);
789 } else {
790 linkerType = isFlat
791 ? MethodType.methodType(void.class, Object.class, long.class, int.class, Class.class, ft)
792 : MethodType.methodType(void.class, Object.class, long.class, ft);
793 }
794 MemberName linker = new MemberName(Unsafe.class, kind.methodName, linkerType, REF_invokeVirtual);
795 try {
796 linker = IMPL_NAMES.resolveOrFail(REF_invokeVirtual, linker, null, LM_TRUSTED,
797 NoSuchMethodException.class);
798 } catch (ReflectiveOperationException ex) {
799 throw newInternalError(ex);
800 }
801
802 // What is the external type of the lambda form?
803 MethodType mtype;
804 if (isGetter)
805 mtype = MethodType.methodType(ft);
806 else
807 mtype = MethodType.methodType(void.class, ft);
808 mtype = mtype.basicType(); // erase short to int, etc.
809 if (!isStatic)
810 mtype = mtype.insertParameterTypes(0, Object.class);
811 final int DMH_THIS = 0;
812 final int ARG_BASE = 1;
813 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
814 // if this is for non-static access, the base pointer is stored at this index:
815 final int OBJ_BASE = isStatic ? -1 : ARG_BASE;
816 // if this is for write access, the value to be written is stored at this index:
817 final int SET_VALUE = isGetter ? -1 : ARG_LIMIT - 1;
818 int nameCursor = ARG_LIMIT;
819 final int F_HOLDER = (isStatic ? nameCursor++ : -1); // static base if any
820 final int F_OFFSET = nameCursor++; // Either static offset or field offset.
821 final int OBJ_CHECK = (OBJ_BASE >= 0 ? nameCursor++ : -1);
822 final int U_HOLDER = nameCursor++; // UNSAFE holder
823 final int INIT_BAR = (needsInit ? nameCursor++ : -1);
824 final int LAYOUT = (isFlat ? nameCursor++ : -1); // field must be instance
825 final int VALUE_TYPE = (isFlat ? nameCursor++ : -1);
826 final int NULL_CHECK = (isNullRestricted && !isGetter ? nameCursor++ : -1);
827 final int PRE_CAST = (needsCast && !isGetter ? nameCursor++ : -1);
828 final int LINKER_CALL = nameCursor++;
829 final int POST_CAST = (needsCast && isGetter ? nameCursor++ : -1);
830 final int RESULT = nameCursor-1; // either the call, or the cast
831 Name[] names = invokeArguments(nameCursor - ARG_LIMIT, mtype);
832 if (needsInit)
833 names[INIT_BAR] = new Name(getFunction(NF_ensureInitialized), names[DMH_THIS]);
834 if (!isGetter) {
835 if (isNullRestricted)
836 names[NULL_CHECK] = new Name(getFunction(NF_nullCheck), names[SET_VALUE]);
837 if (needsCast)
838 names[PRE_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[SET_VALUE]);
839 }
840 Object[] outArgs = new Object[1 + linkerType.parameterCount()];
841 assert (outArgs.length == (isGetter ? 3 : 4) + (isFlat ? 2 : 0));
842 outArgs[0] = names[U_HOLDER] = new Name(getFunction(NF_UNSAFE));
843 if (isStatic) {
844 outArgs[1] = names[F_HOLDER] = new Name(getFunction(NF_staticBase), names[DMH_THIS]);
845 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_staticOffset), names[DMH_THIS]);
846 } else {
847 outArgs[1] = names[OBJ_CHECK] = new Name(getFunction(NF_checkBase), names[OBJ_BASE]);
848 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_fieldOffset), names[DMH_THIS]);
849 }
850 int x = 3;
851 if (isFlat) {
852 assert !isStatic : "static field is flat form requested";
853 outArgs[x++] = names[LAYOUT] = new Name(getFunction(NF_fieldLayout), names[DMH_THIS]);
854 outArgs[x++] = names[VALUE_TYPE] = isStatic ? new Name(getFunction(NF_staticFieldType), names[DMH_THIS])
855 : new Name(getFunction(NF_fieldType), names[DMH_THIS]);
856 }
857 if (!isGetter) {
858 outArgs[x] = (needsCast ? names[PRE_CAST] : names[SET_VALUE]);
859 }
860 for (Object a : outArgs) assert(a != null);
861 names[LINKER_CALL] = new Name(linker, outArgs);
862 if (needsCast && isGetter)
863 names[POST_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[LINKER_CALL]);
864 for (Name n : names) assert(n != null);
865
866 LambdaForm form;
867 if (needsCast || needsInit) {
868 // can't use the pre-generated form when casting and/or initializing
869 form = LambdaForm.create(ARG_LIMIT, names, RESULT);
870 } else {
871 form = LambdaForm.create(ARG_LIMIT, names, RESULT, kind);
872 }
873
874 if (LambdaForm.debugNames()) {
875 // add some detail to the lambdaForm debugname,
876 // significant only for debugging
877 StringBuilder nameBuilder = new StringBuilder(kind.methodName);
878 if (isStatic) {
879 nameBuilder.append("Static");
880 } else {
881 nameBuilder.append("Field");
882 }
883 if (needsCast) {
884 nameBuilder.append("Cast");
885 }
886 if (needsInit) {
887 nameBuilder.append("Init");
888 }
889 LambdaForm.associateWithDebugName(form, nameBuilder.toString());
890 }
891 return form;
892 }
893
894 /**
895 * Pre-initialized NamedFunctions for bootstrapping purposes.
896 */
897 static final byte NF_internalMemberName = 0,
898 NF_internalMemberNameEnsureInit = 1,
899 NF_ensureInitialized = 2,
900 NF_fieldOffset = 3,
901 NF_checkBase = 4,
902 NF_staticBase = 5,
903 NF_staticOffset = 6,
904 NF_checkCast = 7,
905 NF_allocateInstance = 8,
906 NF_constructorMethod = 9,
907 NF_UNSAFE = 10,
908 NF_checkReceiver = 11,
909 NF_fieldType = 12,
910 NF_staticFieldType = 13,
911 NF_fieldLayout = 14,
912 NF_nullCheck = 15,
913 NF_LIMIT = 16;
914
915 private static final @Stable NamedFunction[] NFS = new NamedFunction[NF_LIMIT];
916
917 private static NamedFunction getFunction(byte func) {
918 NamedFunction nf = NFS[func];
919 if (nf != null) {
920 return nf;
921 }
922 // Each nf must be statically invocable or we get tied up in our bootstraps.
923 nf = NFS[func] = createFunction(func);
924 assert(InvokerBytecodeGenerator.isStaticallyInvocable(nf));
925 return nf;
926 }
927
928 private static final MethodType CLS_OBJ_TYPE = MethodType.methodType(Class.class, Object.class);
929 private static final MethodType INT_OBJ_TYPE = MethodType.methodType(int.class, Object.class);
930
931 private static final MethodType OBJ_OBJ_TYPE = MethodType.methodType(Object.class, Object.class);
932
933 private static final MethodType LONG_OBJ_TYPE = MethodType.methodType(long.class, Object.class);
934
935 private static NamedFunction createFunction(byte func) {
936 try {
937 switch (func) {
938 case NF_internalMemberName:
939 return getNamedFunction("internalMemberName", OBJ_OBJ_TYPE);
940 case NF_internalMemberNameEnsureInit:
941 return getNamedFunction("internalMemberNameEnsureInit", OBJ_OBJ_TYPE);
942 case NF_ensureInitialized:
943 return getNamedFunction("ensureInitialized", MethodType.methodType(void.class, Object.class));
944 case NF_fieldOffset:
945 return getNamedFunction("fieldOffset", LONG_OBJ_TYPE);
946 case NF_checkBase:
947 return getNamedFunction("checkBase", OBJ_OBJ_TYPE);
948 case NF_staticBase:
949 return getNamedFunction("staticBase", OBJ_OBJ_TYPE);
950 case NF_staticOffset:
951 return getNamedFunction("staticOffset", LONG_OBJ_TYPE);
952 case NF_checkCast:
953 return getNamedFunction("checkCast", MethodType.methodType(Object.class, Object.class, Object.class));
954 case NF_allocateInstance:
955 return getNamedFunction("allocateInstance", OBJ_OBJ_TYPE);
956 case NF_constructorMethod:
957 return getNamedFunction("constructorMethod", OBJ_OBJ_TYPE);
958 case NF_UNSAFE:
959 MemberName member = new MemberName(MethodHandleStatics.class, "UNSAFE", Unsafe.class, REF_getStatic);
960 return new NamedFunction(
961 MemberName.getFactory().resolveOrFail(REF_getStatic, member,
962 DirectMethodHandle.class, LM_TRUSTED,
963 NoSuchFieldException.class));
964 case NF_checkReceiver:
965 member = new MemberName(DirectMethodHandle.class, "checkReceiver", OBJ_OBJ_TYPE, REF_invokeVirtual);
966 return new NamedFunction(
967 MemberName.getFactory().resolveOrFail(REF_invokeVirtual, member,
968 DirectMethodHandle.class, LM_TRUSTED,
969 NoSuchMethodException.class));
970 case NF_fieldType:
971 return getNamedFunction("fieldType", CLS_OBJ_TYPE);
972 case NF_staticFieldType:
973 return getNamedFunction("staticFieldType", CLS_OBJ_TYPE);
974 case NF_nullCheck:
975 return getNamedFunction("nullCheck", OBJ_OBJ_TYPE);
976 case NF_fieldLayout:
977 return getNamedFunction("fieldLayout", INT_OBJ_TYPE);
978 default:
979 throw newInternalError("Unknown function: " + func);
980 }
981 } catch (ReflectiveOperationException ex) {
982 throw newInternalError(ex);
983 }
984 }
985
986 private static NamedFunction getNamedFunction(String name, MethodType type)
987 throws ReflectiveOperationException
988 {
989 MemberName member = new MemberName(DirectMethodHandle.class, name, type, REF_invokeStatic);
990 return new NamedFunction(
991 MemberName.getFactory().resolveOrFail(REF_invokeStatic, member,
992 DirectMethodHandle.class, LM_TRUSTED,
993 NoSuchMethodException.class));
994 }
995
996 static {
997 // The Holder class will contain pre-generated DirectMethodHandles resolved
998 // speculatively using MemberName.getFactory().resolveOrNull. However, that
999 // doesn't initialize the class, which subtly breaks inlining etc. By forcing
1000 // initialization of the Holder class we avoid these issues.
1001 UNSAFE.ensureClassInitialized(Holder.class);
1002 }
1003
1004 /* Placeholder class for DirectMethodHandles generated ahead of time */
1005 final class Holder {}
1006 }