1 /*
2 * Copyright (c) 2008, 2024, 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.Wrapper;
34
35 import java.util.Arrays;
36 import java.util.Objects;
37 import java.util.function.Function;
38
39 import static java.lang.invoke.LambdaForm.*;
40 import static java.lang.invoke.LambdaForm.Kind.*;
41 import static java.lang.invoke.MethodHandleNatives.Constants.*;
42 import static java.lang.invoke.MethodHandleStatics.UNSAFE;
43 import static java.lang.invoke.MethodHandleStatics.newInternalError;
44 import static java.lang.invoke.MethodTypeForm.*;
45
46 /**
47 * The flavor of method handle which implements a constant reference
48 * to a class member.
49 * @author jrose
50 */
51 sealed class DirectMethodHandle extends MethodHandle {
52 final MemberName member;
53 final boolean crackable;
54
55 // Constructors and factory methods in this class *must* be package scoped or private.
56 private DirectMethodHandle(MethodType mtype, LambdaForm form, MemberName member, boolean crackable) {
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, LM_TRUSTED);
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 this.crackable = crackable;
74 }
75
76 // Factory methods:
77 static DirectMethodHandle make(byte refKind, Class<?> refc, MemberName member, Class<?> callerClass) {
78 MethodType mtype = member.getMethodOrFieldType();
79 if (!member.isStatic()) {
80 if (!member.getDeclaringClass().isAssignableFrom(refc) || member.isConstructor())
81 throw new InternalError(member.toString());
82 mtype = mtype.insertParameterTypes(0, refc);
83 }
84 if (!member.isField()) {
85 // refKind reflects the original type of lookup via findSpecial or
86 // findVirtual etc.
87 return switch (refKind) {
88 case REF_invokeSpecial -> {
89 member = member.asSpecial();
90 // if caller is an interface we need to adapt to get the
91 // receiver check inserted
92 if (callerClass == null) {
93 throw new InternalError("callerClass must not be null for REF_invokeSpecial");
94 }
95 LambdaForm lform = preparedLambdaForm(member, callerClass.isInterface());
96 yield new Special(mtype, lform, member, true, callerClass);
97 }
98 case REF_invokeInterface -> {
99 // for interfaces we always need the receiver typecheck,
100 // so we always pass 'true' to ensure we adapt if needed
101 // to include the REF_invokeSpecial case
102 LambdaForm lform = preparedLambdaForm(member, true);
103 yield new Interface(mtype, lform, member, true, refc);
104 }
105 default -> {
106 LambdaForm lform = preparedLambdaForm(member);
107 yield new DirectMethodHandle(mtype, lform, member, true);
108 }
109 };
110 } else {
111 LambdaForm lform = preparedFieldLambdaForm(member);
112 if (member.isStatic()) {
113 long offset = MethodHandleNatives.staticFieldOffset(member);
114 Object base = MethodHandleNatives.staticFieldBase(member);
115 return new StaticAccessor(mtype, lform, member, true, base, offset);
116 } else {
117 long offset = MethodHandleNatives.objectFieldOffset(member);
118 assert(offset == (int)offset);
119 return new Accessor(mtype, lform, member, true, (int)offset);
120 }
121 }
122 }
123 static DirectMethodHandle make(Class<?> refc, MemberName member) {
124 byte refKind = member.getReferenceKind();
125 if (refKind == REF_invokeSpecial)
126 refKind = REF_invokeVirtual;
127 return make(refKind, refc, member, null /* no callerClass context */);
128 }
129 static DirectMethodHandle make(MemberName member) {
130 if (member.isConstructor())
131 return makeAllocator(member.getDeclaringClass(), member);
132 return make(member.getDeclaringClass(), member);
133 }
134 static DirectMethodHandle makeAllocator(Class<?> instanceClass, MemberName ctor) {
135 assert(ctor.isConstructor() && ctor.getName().equals("<init>"));
136 ctor = ctor.asConstructor();
137 assert(ctor.isConstructor() && ctor.getReferenceKind() == REF_newInvokeSpecial) : ctor;
138 MethodType mtype = ctor.getMethodType().changeReturnType(instanceClass);
139 LambdaForm lform = preparedLambdaForm(ctor);
140 MemberName init = ctor.asSpecial();
141 assert(init.getMethodType().returnType() == void.class);
142 return new Constructor(mtype, lform, ctor, true, init, instanceClass);
143 }
144
145 @Override
146 BoundMethodHandle rebind() {
147 return BoundMethodHandle.makeReinvoker(this);
148 }
149
150 @Override
151 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
152 assert(this.getClass() == DirectMethodHandle.class); // must override in subclasses
153 return new DirectMethodHandle(mt, lf, member, crackable);
154 }
155
156 @Override
157 MethodHandle viewAsType(MethodType newType, boolean strict) {
158 // No actual conversions, just a new view of the same method.
159 // However, we must not expose a DMH that is crackable into a
160 // MethodHandleInfo, so we return a cloned, uncrackable DMH
161 assert(viewAsTypeChecks(newType, strict));
162 assert(this.getClass() == DirectMethodHandle.class); // must override in subclasses
163 return new DirectMethodHandle(newType, form, member, false);
164 }
165
166 @Override
167 boolean isCrackable() {
168 return crackable;
169 }
170
171 @Override
172 String internalProperties(int indentLevel) {
173 return "\n" + debugPrefix(indentLevel) + "& DMH.MN=" + internalMemberName();
174 }
175
176 //// Implementation methods.
177 @Override
178 @ForceInline
179 MemberName internalMemberName() {
180 return member;
181 }
182
183 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
184
185 /**
186 * Create a LF which can invoke the given method.
187 * Cache and share this structure among all methods with
188 * the same basicType and refKind.
189 */
190 private static LambdaForm preparedLambdaForm(MemberName m, boolean adaptToSpecialIfc) {
191 assert(m.isInvocable()) : m; // call preparedFieldLambdaForm instead
192 MethodType mtype = m.getInvocationType().basicType();
193 assert(!m.isMethodHandleInvoke()) : m;
194 // MemberName.getReferenceKind represents the JVM optimized form of the call
195 // as distinct from the "kind" passed to DMH.make which represents the original
196 // bytecode-equivalent request. Specifically private/final methods that use a direct
197 // call have getReferenceKind adapted to REF_invokeSpecial, even though the actual
198 // invocation mode may be invokevirtual or invokeinterface.
199 int which = switch (m.getReferenceKind()) {
200 case REF_invokeVirtual -> LF_INVVIRTUAL;
201 case REF_invokeStatic -> LF_INVSTATIC;
202 case REF_invokeSpecial -> LF_INVSPECIAL;
203 case REF_invokeInterface -> LF_INVINTERFACE;
204 case REF_newInvokeSpecial -> LF_NEWINVSPECIAL;
205 default -> throw new InternalError(m.toString());
206 };
207 if (which == LF_INVSTATIC && shouldBeInitialized(m)) {
208 // precompute the barrier-free version:
209 preparedLambdaForm(mtype, which);
210 which = LF_INVSTATIC_INIT;
211 }
212 if (which == LF_INVSPECIAL && adaptToSpecialIfc) {
213 which = LF_INVSPECIAL_IFC;
214 }
215 LambdaForm lform = preparedLambdaForm(mtype, which);
216 maybeCompile(lform, m);
217 assert(lform.methodType().dropParameterTypes(0, 1)
218 .equals(m.getInvocationType().basicType()))
219 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
220 return lform;
221 }
222
223 private static LambdaForm preparedLambdaForm(MemberName m) {
224 return preparedLambdaForm(m, false);
225 }
226
227 private static LambdaForm preparedLambdaForm(MethodType mtype, int which) {
228 LambdaForm lform = mtype.form().cachedLambdaForm(which);
229 if (lform != null) return lform;
230 lform = makePreparedLambdaForm(mtype, which);
231 return mtype.form().setCachedLambdaForm(which, lform);
232 }
233
234 static LambdaForm makePreparedLambdaForm(MethodType mtype, int which) {
235 boolean needsInit = (which == LF_INVSTATIC_INIT);
236 boolean doesAlloc = (which == LF_NEWINVSPECIAL);
237 boolean needsReceiverCheck = (which == LF_INVINTERFACE ||
238 which == LF_INVSPECIAL_IFC);
239
240 String linkerName;
241 LambdaForm.Kind kind;
242 switch (which) {
243 case LF_INVVIRTUAL: linkerName = "linkToVirtual"; kind = DIRECT_INVOKE_VIRTUAL; break;
244 case LF_INVSTATIC: linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC; break;
245 case LF_INVSTATIC_INIT:linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC_INIT; break;
246 case LF_INVSPECIAL_IFC:linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL_IFC; break;
247 case LF_INVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL; break;
248 case LF_INVINTERFACE: linkerName = "linkToInterface"; kind = DIRECT_INVOKE_INTERFACE; break;
249 case LF_NEWINVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_NEW_INVOKE_SPECIAL; break;
250 default: throw new InternalError("which="+which);
251 }
252
253 MethodType mtypeWithArg;
254 if (doesAlloc) {
255 var ptypes = mtype.ptypes();
256 var newPtypes = new Class<?>[ptypes.length + 2];
257 newPtypes[0] = Object.class; // insert newly allocated obj
258 System.arraycopy(ptypes, 0, newPtypes, 1, ptypes.length);
259 newPtypes[newPtypes.length - 1] = MemberName.class;
260 mtypeWithArg = MethodType.methodType(void.class, newPtypes, true);
261 } else {
262 mtypeWithArg = mtype.appendParameterTypes(MemberName.class);
263 }
264 MemberName linker = new MemberName(MethodHandle.class, linkerName, mtypeWithArg, REF_invokeStatic);
265 try {
266 linker = IMPL_NAMES.resolveOrFail(REF_invokeStatic, linker, null, LM_TRUSTED,
267 NoSuchMethodException.class);
268 } catch (ReflectiveOperationException ex) {
269 throw newInternalError(ex);
270 }
271 final int DMH_THIS = 0;
272 final int ARG_BASE = 1;
273 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
274 int nameCursor = ARG_LIMIT;
275 final int NEW_OBJ = (doesAlloc ? nameCursor++ : -1);
276 final int GET_MEMBER = nameCursor++;
277 final int CHECK_RECEIVER = (needsReceiverCheck ? nameCursor++ : -1);
278 final int LINKER_CALL = nameCursor++;
279 Name[] names = invokeArguments(nameCursor - ARG_LIMIT, mtype);
280 assert(names.length == nameCursor);
281 if (doesAlloc) {
282 // names = { argx,y,z,... new C, init method }
283 names[NEW_OBJ] = new Name(getFunction(NF_allocateInstance), names[DMH_THIS]);
284 names[GET_MEMBER] = new Name(getFunction(NF_constructorMethod), names[DMH_THIS]);
285 } else if (needsInit) {
286 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberNameEnsureInit), names[DMH_THIS]);
287 } else {
288 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberName), names[DMH_THIS]);
289 }
290 assert(findDirectMethodHandle(names[GET_MEMBER]) == names[DMH_THIS]);
291 Object[] outArgs = Arrays.copyOfRange(names, ARG_BASE, GET_MEMBER+1, Object[].class);
292 if (needsReceiverCheck) {
293 names[CHECK_RECEIVER] = new Name(getFunction(NF_checkReceiver), names[DMH_THIS], names[ARG_BASE]);
294 outArgs[0] = names[CHECK_RECEIVER];
295 }
296 assert(outArgs[outArgs.length-1] == names[GET_MEMBER]); // look, shifted args!
297 int result = LAST_RESULT;
298 if (doesAlloc) {
299 assert(outArgs[outArgs.length-2] == names[NEW_OBJ]); // got to move this one
300 System.arraycopy(outArgs, 0, outArgs, 1, outArgs.length-2);
301 outArgs[0] = names[NEW_OBJ];
302 result = NEW_OBJ;
303 }
304 names[LINKER_CALL] = new Name(linker, outArgs);
305 LambdaForm lform = LambdaForm.create(ARG_LIMIT, names, result, kind);
306
307 // This is a tricky bit of code. Don't send it through the LF interpreter.
308 lform.compileToBytecode();
309 return lform;
310 }
311
312 /* assert */ static Object findDirectMethodHandle(Name name) {
313 if (name.function.equals(getFunction(NF_internalMemberName)) ||
314 name.function.equals(getFunction(NF_internalMemberNameEnsureInit)) ||
315 name.function.equals(getFunction(NF_constructorMethod))) {
316 assert(name.arguments.length == 1);
317 return name.arguments[0];
318 }
319 return null;
320 }
321
322 private static void maybeCompile(LambdaForm lform, MemberName m) {
323 if (lform.vmentry == null && VerifyAccess.isSamePackage(m.getDeclaringClass(), MethodHandle.class))
324 // Help along bootstrapping...
325 lform.compileToBytecode();
326 }
327
328 /** Static wrapper for DirectMethodHandle.internalMemberName. */
329 @ForceInline
330 /*non-public*/
331 static Object internalMemberName(Object mh) {
332 return ((DirectMethodHandle)mh).member;
333 }
334
335 /** Static wrapper for DirectMethodHandle.internalMemberName.
336 * This one also forces initialization.
337 */
338 /*non-public*/
339 static Object internalMemberNameEnsureInit(Object mh) {
340 DirectMethodHandle dmh = (DirectMethodHandle)mh;
341 dmh.ensureInitialized();
342 return dmh.member;
343 }
344
345 /*non-public*/
346 static boolean shouldBeInitialized(MemberName member) {
347 switch (member.getReferenceKind()) {
348 case REF_invokeStatic:
349 case REF_getStatic:
350 case REF_putStatic:
351 case REF_newInvokeSpecial:
352 break;
353 default:
354 // No need to initialize the class on this kind of member.
355 return false;
356 }
357 Class<?> cls = member.getDeclaringClass();
358 if (cls == ValueConversions.class ||
359 cls == MethodHandleImpl.class ||
360 cls == Invokers.class) {
361 // These guys have lots of <clinit> DMH creation but we know
362 // the MHs will not be used until the system is booted.
363 return false;
364 }
365 if (VerifyAccess.isSamePackage(MethodHandle.class, cls) ||
366 VerifyAccess.isSamePackage(ValueConversions.class, cls)) {
367 // It is a system class. It is probably in the process of
368 // being initialized, but we will help it along just to be safe.
369 UNSAFE.ensureClassInitialized(cls);
370 return false;
371 }
372 return UNSAFE.shouldBeInitialized(cls);
373 }
374
375 private void ensureInitialized() {
376 if (checkInitialized(member)) {
377 // The coast is clear. Delete the <clinit> barrier.
378 updateForm(new Function<>() {
379 public LambdaForm apply(LambdaForm oldForm) {
380 return (member.isField() ? preparedFieldLambdaForm(member)
381 : preparedLambdaForm(member));
382 }
383 });
384 }
385 }
386 private static boolean checkInitialized(MemberName member) {
387 Class<?> defc = member.getDeclaringClass();
388 UNSAFE.ensureClassInitialized(defc);
389 // Once we get here either defc was fully initialized by another thread, or
390 // defc was already being initialized by the current thread. In the latter case
391 // the barrier must remain. We can detect this simply by checking if initialization
392 // is still needed.
393 return !UNSAFE.shouldBeInitialized(defc);
394 }
395
396 /*non-public*/
397 static void ensureInitialized(Object mh) {
398 ((DirectMethodHandle)mh).ensureInitialized();
399 }
400
401 /** This subclass represents invokespecial instructions. */
402 static final class Special extends DirectMethodHandle {
403 private final Class<?> caller;
404 private Special(MethodType mtype, LambdaForm form, MemberName member, boolean crackable, Class<?> caller) {
405 super(mtype, form, member, crackable);
406 this.caller = caller;
407 }
408 @Override
409 boolean isInvokeSpecial() {
410 return true;
411 }
412 @Override
413 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
414 return new Special(mt, lf, member, crackable, caller);
415 }
416 @Override
417 MethodHandle viewAsType(MethodType newType, boolean strict) {
418 assert(viewAsTypeChecks(newType, strict));
419 return new Special(newType, form, member, false, caller);
420 }
421 Object checkReceiver(Object recv) {
422 if (!caller.isInstance(recv)) {
423 if (recv != null) {
424 String msg = String.format("Receiver class %s is not a subclass of caller class %s",
425 recv.getClass().getName(), caller.getName());
426 throw new IncompatibleClassChangeError(msg);
427 } else {
428 String msg = String.format("Cannot invoke %s with null receiver", member);
429 throw new NullPointerException(msg);
430 }
431 }
432 return recv;
433 }
434 }
435
436 /** This subclass represents invokeinterface instructions. */
437 static final class Interface extends DirectMethodHandle {
438 private final Class<?> refc;
439 private Interface(MethodType mtype, LambdaForm form, MemberName member, boolean crackable, Class<?> refc) {
440 super(mtype, form, member, crackable);
441 assert(refc.isInterface()) : refc;
442 this.refc = refc;
443 }
444 @Override
445 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
446 return new Interface(mt, lf, member, crackable, refc);
447 }
448 @Override
449 MethodHandle viewAsType(MethodType newType, boolean strict) {
450 assert(viewAsTypeChecks(newType, strict));
451 return new Interface(newType, form, member, false, refc);
452 }
453 @Override
454 Object checkReceiver(Object recv) {
455 if (!refc.isInstance(recv)) {
456 if (recv != null) {
457 String msg = String.format("Receiver class %s does not implement the requested interface %s",
458 recv.getClass().getName(), refc.getName());
459 throw new IncompatibleClassChangeError(msg);
460 } else {
461 String msg = String.format("Cannot invoke %s with null receiver", member);
462 throw new NullPointerException(msg);
463 }
464 }
465 return recv;
466 }
467 }
468
469 /** Used for interface receiver type checks, by Interface and Special modes. */
470 Object checkReceiver(Object recv) {
471 throw new InternalError("Should only be invoked on a subclass");
472 }
473
474 /** This subclass handles constructor references. */
475 static final class Constructor extends DirectMethodHandle {
476 final MemberName initMethod;
477 final Class<?> instanceClass;
478
479 private Constructor(MethodType mtype, LambdaForm form, MemberName constructor,
480 boolean crackable, MemberName initMethod, Class<?> instanceClass) {
481 super(mtype, form, constructor, crackable);
482 this.initMethod = initMethod;
483 this.instanceClass = instanceClass;
484 assert(initMethod.isResolved());
485 }
486 @Override
487 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
488 return new Constructor(mt, lf, member, crackable, initMethod, instanceClass);
489 }
490 @Override
491 MethodHandle viewAsType(MethodType newType, boolean strict) {
492 assert(viewAsTypeChecks(newType, strict));
493 return new Constructor(newType, form, member, false, initMethod, instanceClass);
494 }
495 }
496
497 /*non-public*/
498 static Object constructorMethod(Object mh) {
499 Constructor dmh = (Constructor)mh;
500 return dmh.initMethod;
501 }
502
503 /*non-public*/
504 static Object allocateInstance(Object mh) throws InstantiationException {
505 Constructor dmh = (Constructor)mh;
506 return UNSAFE.allocateInstance(dmh.instanceClass);
507 }
508
509 /** This subclass handles non-static field references. */
510 static final class Accessor extends DirectMethodHandle {
511 final Class<?> fieldType;
512 final int fieldOffset;
513 private Accessor(MethodType mtype, LambdaForm form, MemberName member,
514 boolean crackable, int fieldOffset) {
515 super(mtype, form, member, crackable);
516 this.fieldType = member.getFieldType();
517 this.fieldOffset = fieldOffset;
518 }
519
520 @Override Object checkCast(Object obj) {
521 return fieldType.cast(obj);
522 }
523 @Override
524 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
525 return new Accessor(mt, lf, member, crackable, fieldOffset);
526 }
527 @Override
528 MethodHandle viewAsType(MethodType newType, boolean strict) {
529 assert(viewAsTypeChecks(newType, strict));
530 return new Accessor(newType, form, member, false, fieldOffset);
531 }
532 }
533
534 @ForceInline
535 /*non-public*/
536 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*/
544 static Object checkBase(Object obj) {
545 // Note that the object's class has already been verified,
546 // since the parameter type of the Accessor method handle
547 // is either member.getDeclaringClass or a subclass.
548 // This was verified in DirectMethodHandle.make.
549 // Therefore, the only remaining check is for null.
550 // Since this check is *not* guaranteed by Unsafe.getInt
551 // and its siblings, we need to make an explicit one here.
552 return Objects.requireNonNull(obj);
553 }
554
555 /** This subclass handles static field references. */
556 static final class StaticAccessor extends DirectMethodHandle {
557 private final Class<?> fieldType;
558 private final Object staticBase;
559 private final long staticOffset;
560
561 private StaticAccessor(MethodType mtype, LambdaForm form, MemberName member,
562 boolean crackable, Object staticBase, long staticOffset) {
563 super(mtype, form, member, crackable);
564 this.fieldType = member.getFieldType();
565 this.staticBase = staticBase;
566 this.staticOffset = staticOffset;
567 }
568
569 @Override Object checkCast(Object obj) {
570 return fieldType.cast(obj);
571 }
572 @Override
573 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
574 return new StaticAccessor(mt, lf, member, crackable, staticBase, staticOffset);
575 }
576 @Override
577 MethodHandle viewAsType(MethodType newType, boolean strict) {
578 assert(viewAsTypeChecks(newType, strict));
579 return new StaticAccessor(newType, form, member, false, staticBase, staticOffset);
580 }
581 }
582
583 @ForceInline
584 /*non-public*/
585 static Object nullCheck(Object obj) {
586 return Objects.requireNonNull(obj);
587 }
588
589 @ForceInline
590 /*non-public*/
591 static Object staticBase(Object accessorObj) {
592 return ((StaticAccessor)accessorObj).staticBase;
593 }
594
595 @ForceInline
596 /*non-public*/
597 static long staticOffset(Object accessorObj) {
598 return ((StaticAccessor)accessorObj).staticOffset;
599 }
600
601 @ForceInline
602 /*non-public*/
603 static Object checkCast(Object mh, Object obj) {
604 return ((DirectMethodHandle) mh).checkCast(obj);
605 }
606
607 Object checkCast(Object obj) {
608 return member.getMethodType().returnType().cast(obj);
609 }
610
611 // Caching machinery for field accessors:
612 static final byte
613 AF_GETFIELD = 0,
614 AF_PUTFIELD = 1,
615 AF_GETSTATIC = 2,
616 AF_PUTSTATIC = 3,
617 AF_GETSTATIC_INIT = 4,
618 AF_PUTSTATIC_INIT = 5,
619 AF_LIMIT = 6;
620 // Enumerate the different field kinds using Wrapper,
621 // with an extra case added for checked references.
622 static final int
623 FT_LAST_WRAPPER = Wrapper.COUNT-1,
624 FT_UNCHECKED_REF = Wrapper.OBJECT.ordinal(),
625 FT_CHECKED_REF = FT_LAST_WRAPPER+1,
626 FT_LIMIT = FT_LAST_WRAPPER+2;
627 private static int afIndex(byte formOp, boolean isVolatile, int ftypeKind) {
628 return ((formOp * FT_LIMIT * 2)
629 + (isVolatile ? FT_LIMIT : 0)
630 + ftypeKind);
631 }
632 @Stable
633 private static final LambdaForm[] ACCESSOR_FORMS
634 = new LambdaForm[afIndex(AF_LIMIT, false, 0)];
635 static int ftypeKind(Class<?> ftype) {
636 if (ftype.isPrimitive()) {
637 return Wrapper.forPrimitiveType(ftype).ordinal();
638 } else if (ftype.isInterface() || ftype.isAssignableFrom(Object.class)) {
639 // retyping can be done without a cast
640 return FT_UNCHECKED_REF;
641 } else {
642 return FT_CHECKED_REF;
643 }
644 }
645
646 /**
647 * Create a LF which can access the given field.
648 * Cache and share this structure among all fields with
649 * the same basicType and refKind.
650 */
651 private static LambdaForm preparedFieldLambdaForm(MemberName m) {
652 Class<?> ftype = m.getFieldType();
653 boolean isVolatile = m.isVolatile();
654 byte formOp = switch (m.getReferenceKind()) {
655 case REF_getField -> AF_GETFIELD;
656 case REF_putField -> AF_PUTFIELD;
657 case REF_getStatic -> AF_GETSTATIC;
658 case REF_putStatic -> AF_PUTSTATIC;
659 default -> throw new InternalError(m.toString());
660 };
661 if (shouldBeInitialized(m)) {
662 // precompute the barrier-free version:
663 preparedFieldLambdaForm(formOp, isVolatile, ftype);
664 assert((AF_GETSTATIC_INIT - AF_GETSTATIC) ==
665 (AF_PUTSTATIC_INIT - AF_PUTSTATIC));
666 formOp += (AF_GETSTATIC_INIT - AF_GETSTATIC);
667 }
668 LambdaForm lform = preparedFieldLambdaForm(formOp, isVolatile, ftype);
669 maybeCompile(lform, m);
670 assert(lform.methodType().dropParameterTypes(0, 1)
671 .equals(m.getInvocationType().basicType()))
672 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
673 return lform;
674 }
675 private static LambdaForm preparedFieldLambdaForm(byte formOp, boolean isVolatile, Class<?> ftype) {
676 int ftypeKind = ftypeKind(ftype);
677 int afIndex = afIndex(formOp, isVolatile, ftypeKind);
678 LambdaForm lform = ACCESSOR_FORMS[afIndex];
679 if (lform != null) return lform;
680 lform = makePreparedFieldLambdaForm(formOp, isVolatile, ftypeKind);
681 ACCESSOR_FORMS[afIndex] = lform; // don't bother with a CAS
682 return lform;
683 }
684
685 private static final Wrapper[] ALL_WRAPPERS = Wrapper.values();
686
687 private static Kind getFieldKind(boolean isGetter, boolean isVolatile, Wrapper wrapper) {
688 if (isGetter) {
689 if (isVolatile) {
690 switch (wrapper) {
691 case BOOLEAN: return GET_BOOLEAN_VOLATILE;
692 case BYTE: return GET_BYTE_VOLATILE;
693 case SHORT: return GET_SHORT_VOLATILE;
694 case CHAR: return GET_CHAR_VOLATILE;
695 case INT: return GET_INT_VOLATILE;
696 case LONG: return GET_LONG_VOLATILE;
697 case FLOAT: return GET_FLOAT_VOLATILE;
698 case DOUBLE: return GET_DOUBLE_VOLATILE;
699 case OBJECT: return GET_REFERENCE_VOLATILE;
700 }
701 } else {
702 switch (wrapper) {
703 case BOOLEAN: return GET_BOOLEAN;
704 case BYTE: return GET_BYTE;
705 case SHORT: return GET_SHORT;
706 case CHAR: return GET_CHAR;
707 case INT: return GET_INT;
708 case LONG: return GET_LONG;
709 case FLOAT: return GET_FLOAT;
710 case DOUBLE: return GET_DOUBLE;
711 case OBJECT: return GET_REFERENCE;
712 }
713 }
714 } else {
715 if (isVolatile) {
716 switch (wrapper) {
717 case BOOLEAN: return PUT_BOOLEAN_VOLATILE;
718 case BYTE: return PUT_BYTE_VOLATILE;
719 case SHORT: return PUT_SHORT_VOLATILE;
720 case CHAR: return PUT_CHAR_VOLATILE;
721 case INT: return PUT_INT_VOLATILE;
722 case LONG: return PUT_LONG_VOLATILE;
723 case FLOAT: return PUT_FLOAT_VOLATILE;
724 case DOUBLE: return PUT_DOUBLE_VOLATILE;
725 case OBJECT: return PUT_REFERENCE_VOLATILE;
726 }
727 } else {
728 switch (wrapper) {
729 case BOOLEAN: return PUT_BOOLEAN;
730 case BYTE: return PUT_BYTE;
731 case SHORT: return PUT_SHORT;
732 case CHAR: return PUT_CHAR;
733 case INT: return PUT_INT;
734 case LONG: return PUT_LONG;
735 case FLOAT: return PUT_FLOAT;
736 case DOUBLE: return PUT_DOUBLE;
737 case OBJECT: return PUT_REFERENCE;
738 }
739 }
740 }
741 throw new AssertionError("Invalid arguments");
742 }
743
744 static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, int ftypeKind) {
745 boolean isGetter = (formOp & 1) == (AF_GETFIELD & 1);
746 boolean isStatic = (formOp >= AF_GETSTATIC);
747 boolean needsInit = (formOp >= AF_GETSTATIC_INIT);
748 boolean needsCast = (ftypeKind == FT_CHECKED_REF);
749 Wrapper fw = (needsCast ? Wrapper.OBJECT : ALL_WRAPPERS[ftypeKind]);
750 Class<?> ft = fw.primitiveType();
751 assert(ftypeKind(needsCast ? String.class : ft) == ftypeKind);
752
753 // getObject, putIntVolatile, etc.
754 Kind kind = getFieldKind(isGetter, isVolatile, fw);
755
756 MethodType linkerType;
757 if (isGetter)
758 linkerType = MethodType.methodType(ft, Object.class, long.class);
759 else
760 linkerType = MethodType.methodType(void.class, Object.class, long.class, ft);
761 MemberName linker = new MemberName(Unsafe.class, kind.methodName, linkerType, REF_invokeVirtual);
762 try {
763 linker = IMPL_NAMES.resolveOrFail(REF_invokeVirtual, linker, null, LM_TRUSTED,
764 NoSuchMethodException.class);
765 } catch (ReflectiveOperationException ex) {
766 throw newInternalError(ex);
767 }
768
769 // What is the external type of the lambda form?
770 MethodType mtype;
771 if (isGetter)
772 mtype = MethodType.methodType(ft);
773 else
774 mtype = MethodType.methodType(void.class, ft);
775 mtype = mtype.basicType(); // erase short to int, etc.
776 if (!isStatic)
777 mtype = mtype.insertParameterTypes(0, Object.class);
778 final int DMH_THIS = 0;
779 final int ARG_BASE = 1;
780 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
781 // if this is for non-static access, the base pointer is stored at this index:
782 final int OBJ_BASE = isStatic ? -1 : ARG_BASE;
783 // if this is for write access, the value to be written is stored at this index:
784 final int SET_VALUE = isGetter ? -1 : ARG_LIMIT - 1;
785 int nameCursor = ARG_LIMIT;
786 final int F_HOLDER = (isStatic ? nameCursor++ : -1); // static base if any
787 final int F_OFFSET = nameCursor++; // Either static offset or field offset.
788 final int OBJ_CHECK = (OBJ_BASE >= 0 ? nameCursor++ : -1);
789 final int U_HOLDER = nameCursor++; // UNSAFE holder
790 final int INIT_BAR = (needsInit ? nameCursor++ : -1);
791 final int PRE_CAST = (needsCast && !isGetter ? nameCursor++ : -1);
792 final int LINKER_CALL = nameCursor++;
793 final int POST_CAST = (needsCast && isGetter ? nameCursor++ : -1);
794 final int RESULT = nameCursor-1; // either the call or the cast
795 Name[] names = invokeArguments(nameCursor - ARG_LIMIT, mtype);
796 if (needsInit)
797 names[INIT_BAR] = new Name(getFunction(NF_ensureInitialized), names[DMH_THIS]);
798 if (needsCast && !isGetter)
799 names[PRE_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[SET_VALUE]);
800 Object[] outArgs = new Object[1 + linkerType.parameterCount()];
801 assert(outArgs.length == (isGetter ? 3 : 4));
802 outArgs[0] = names[U_HOLDER] = new Name(getFunction(NF_UNSAFE));
803 if (isStatic) {
804 outArgs[1] = names[F_HOLDER] = new Name(getFunction(NF_staticBase), names[DMH_THIS]);
805 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_staticOffset), names[DMH_THIS]);
806 } else {
807 outArgs[1] = names[OBJ_CHECK] = new Name(getFunction(NF_checkBase), names[OBJ_BASE]);
808 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_fieldOffset), names[DMH_THIS]);
809 }
810 if (!isGetter) {
811 outArgs[3] = (needsCast ? names[PRE_CAST] : names[SET_VALUE]);
812 }
813 for (Object a : outArgs) assert(a != null);
814 names[LINKER_CALL] = new Name(linker, outArgs);
815 if (needsCast && isGetter)
816 names[POST_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[LINKER_CALL]);
817 for (Name n : names) assert(n != null);
818
819 LambdaForm form;
820 if (needsCast || needsInit) {
821 // can't use the pre-generated form when casting and/or initializing
822 form = LambdaForm.create(ARG_LIMIT, names, RESULT);
823 } else {
824 form = LambdaForm.create(ARG_LIMIT, names, RESULT, kind);
825 }
826
827 if (LambdaForm.debugNames()) {
828 // add some detail to the lambdaForm debugname,
829 // significant only for debugging
830 StringBuilder nameBuilder = new StringBuilder(kind.methodName);
831 if (isStatic) {
832 nameBuilder.append("Static");
833 } else {
834 nameBuilder.append("Field");
835 }
836 if (needsCast) {
837 nameBuilder.append("Cast");
838 }
839 if (needsInit) {
840 nameBuilder.append("Init");
841 }
842 LambdaForm.associateWithDebugName(form, nameBuilder.toString());
843 }
844 return form;
845 }
846
847 /**
848 * Pre-initialized NamedFunctions for bootstrapping purposes.
849 */
850 static final byte NF_internalMemberName = 0,
851 NF_internalMemberNameEnsureInit = 1,
852 NF_ensureInitialized = 2,
853 NF_fieldOffset = 3,
854 NF_checkBase = 4,
855 NF_staticBase = 5,
856 NF_staticOffset = 6,
857 NF_checkCast = 7,
858 NF_allocateInstance = 8,
859 NF_constructorMethod = 9,
860 NF_UNSAFE = 10,
861 NF_checkReceiver = 11,
862 NF_LIMIT = 12;
863
864 private static final @Stable NamedFunction[] NFS = new NamedFunction[NF_LIMIT];
865
866 private static NamedFunction getFunction(byte func) {
867 NamedFunction nf = NFS[func];
868 if (nf != null) {
869 return nf;
870 }
871 // Each nf must be statically invocable or we get tied up in our bootstraps.
872 nf = NFS[func] = createFunction(func);
873 assert(InvokerBytecodeGenerator.isStaticallyInvocable(nf));
874 return nf;
875 }
876
877 static class AOTHolder {
878 private static final MethodType OBJ_OBJ_TYPE = MethodType.methodType(Object.class, Object.class);
879 private static final MethodType LONG_OBJ_TYPE = MethodType.methodType(long.class, Object.class);
880 }
881
882 private static NamedFunction createFunction(byte func) {
883 try {
884 switch (func) {
885 case NF_internalMemberName:
886 return getNamedFunction("internalMemberName", AOTHolder.OBJ_OBJ_TYPE);
887 case NF_internalMemberNameEnsureInit:
888 return getNamedFunction("internalMemberNameEnsureInit", AOTHolder.OBJ_OBJ_TYPE);
889 case NF_ensureInitialized:
890 return getNamedFunction("ensureInitialized", MethodType.methodType(void.class, Object.class));
891 case NF_fieldOffset:
892 return getNamedFunction("fieldOffset", AOTHolder.LONG_OBJ_TYPE);
893 case NF_checkBase:
894 return getNamedFunction("checkBase", AOTHolder.OBJ_OBJ_TYPE);
895 case NF_staticBase:
896 return getNamedFunction("staticBase", AOTHolder.OBJ_OBJ_TYPE);
897 case NF_staticOffset:
898 return getNamedFunction("staticOffset", AOTHolder.LONG_OBJ_TYPE);
899 case NF_checkCast:
900 return getNamedFunction("checkCast", MethodType.methodType(Object.class, Object.class, Object.class));
901 case NF_allocateInstance:
902 return getNamedFunction("allocateInstance", AOTHolder.OBJ_OBJ_TYPE);
903 case NF_constructorMethod:
904 return getNamedFunction("constructorMethod", AOTHolder.OBJ_OBJ_TYPE);
905 case NF_UNSAFE:
906 MemberName member = new MemberName(MethodHandleStatics.class, "UNSAFE", Unsafe.class, REF_getStatic);
907 return new NamedFunction(
908 MemberName.getFactory().resolveOrFail(REF_getStatic, member,
909 DirectMethodHandle.class, LM_TRUSTED,
910 NoSuchFieldException.class));
911 case NF_checkReceiver:
912 member = new MemberName(DirectMethodHandle.class, "checkReceiver", AOTHolder.OBJ_OBJ_TYPE, REF_invokeVirtual);
913 return new NamedFunction(
914 MemberName.getFactory().resolveOrFail(REF_invokeVirtual, member,
915 DirectMethodHandle.class, LM_TRUSTED,
916 NoSuchMethodException.class));
917 default:
918 throw newInternalError("Unknown function: " + func);
919 }
920 } catch (ReflectiveOperationException ex) {
921 throw newInternalError(ex);
922 }
923 }
924
925 private static NamedFunction getNamedFunction(String name, MethodType type)
926 throws ReflectiveOperationException
927 {
928 MemberName member = new MemberName(DirectMethodHandle.class, name, type, REF_invokeStatic);
929 return new NamedFunction(
930 MemberName.getFactory().resolveOrFail(REF_invokeStatic, member,
931 DirectMethodHandle.class, LM_TRUSTED,
932 NoSuchMethodException.class));
933 }
934
935 static {
936 // The Holder class will contain pre-generated DirectMethodHandles resolved
937 // speculatively using MemberName.getFactory().resolveOrNull. However, that
938 // doesn't initialize the class, which subtly breaks inlining etc. By forcing
939 // initialization of the Holder class we avoid these issues.
940 UNSAFE.ensureClassInitialized(Holder.class);
941 }
942
943 /* Placeholder class for DirectMethodHandles generated ahead of time */
944 final class Holder {}
945 }